US 3331020 A
Description (OCR text may contain errors)
July 11, 1967 R. FARENKOPF 3,331,020
MOISTURE DETECTING APPARATUS INCLUDING A BIAS CONTROL FOR SEPARATELY CONTROLLING THE BIAS APPLIED TO THE BASES OF AT LEAST ONE TRANSISTOR RELATIVE TO ANOTHER Filed Dec. 27, 1962 HTTOR Y1 Ey United States Patent MOISTURE DETECTING APPARATUS INCLUDING A BIAS CONTROL FOR SEPARATELY CONTROL- LING THE BIAS APPLIED TO THE BASES OF AT LEAST ONE TRANSISTOR RELATIVE TO AN- OTHER Rudi Farenkopf, Renningen, Wurttemberg, Germany, assignor to K. P. Mundinger G.m.b.H., Renningen, Warttemberg, Germany Filed Dec. 27, 1962, Ser. No. 247,623 9 Claims. (Cl. 324-65) The present invention relates to a moisture meter for measuring the moisture content of different materials or articles.
Similar moisture meters according to the prior art are generally provided with amplifiers which require electron tubes and are therefore not only of a considerable size and weight but are also very delicate and fragile and susceptible to trouble. They are easily damaged When handled too roughly and then fail to operate, especially when used for carrying out measurements outside of a building or in storage sheds, for example, when used for measuring the moisture content of lumber, grain, or the like.
It is the principal object of the present invention to provide a moisture meter which overcomes the abovementioned disadvantages. For attaining this object, the moisture meter according to the invention which is especially intended for determining the moisture content of solid materials by measuring the electrical resistance thereof by means of electrodes which are applied upon or n inserted into the material to be measured is provided with a transistor which is connected between the measuring electrodes and the indicating instrument and operates as an amplifier. In order to eleminate the effects of variations in voltage and temperature, the apparatus according to the invention employs two transistors which are connected symmetrically in opposition to each other or at least two transistors which are connected in series.
While an amplifying circuit employing electron tubes always requires a relatively high filament power and therefore batteries of a considerable size and weight which render such a portable apparatus very heavy, bulky, and hard to manipulate, this disadvantage is overcome according to the invention since the transistors employed therein require hardly any power. The voltage required for the operation of the transistors may be supplied by a small long-lasting battery and the measuring instrument may therefore be of a small size, light weight, easy to manipulate, relatively shock-proof, and not susceptible to trouble and breakdowns.
Detailed tests have also revealed that the logarithmic dependency of the resistance upon the moisture content of the particular material or article to be measured can be adapted without difficulty to the exponential characteristic of the transistors. The indicating instrument of the measuring apparatus according to the invention may therefore be provided with a practically linear indicating scale which may extend, for example, from about 40 kn to about 100 M9. Furthermore, this apparatus indicates the moisture content within a wide range independently of variations in voltage or temperature as well as quickly, reliably, and accurately. It may also be employed for many different purposes especially since its function and operation of determining the moisture content of a ma 3,33ifi2fi Patented July 11, 1967 terial or article is entirely independent of the type and nature of such a material or article. This is due to the fact that, because of the unique characteristics of transistors insofar as their amplifying effects may be varied by different circuit connections and different connections of their electrodes, it is possible to adapt the measuring circuit to many different requirements which may occur in actual practice. In order to comply with the particular requirements upon the measuring procedure and the sensitivity of the indicating instrument of the apparatus in measuring the moisture content of different articles or materials, it is possible to vary the individual elements of the apparatus by selecting the type and size most suitable for the particular measurement.
The features and advantages of the present invention will become more clearly apparent from the following detailed description thereof which is to be read with reference to the accompanying drawings, in which FIGURES 1 to 3 show three different circuit diagrams of a measuring apparatus employing a transistor amplifier according to the invention.
In the drawings, FIG. 1 and FIG. 2 each show a circuit in which two transistors are connected symmetrically in opposition to each other, while FIGURE 3 shows a circuit in which two transistors are connected in series. of course, these circuits are to be regarded merely as examples of the manner in which the invention may be applied inasmuch as many other suitable circuits including those with more than two transistors may be devised without departing from the scope of the invention.
In the circuit of the apparatus as illustrated in FIGURE 1, a source of current U which may consist, for example, of a dry-cell battery, is bridged by an adjustable potentiometer S. The resistance R to *be measured is connected at one side to the current source U and at the other side to the emitters of the two transistors T and T between which, if desired, coupling resistances K may be connected. The base of each transistor T and T is connected to the potentiometer S which bridges the current source U and is also connected through a variable balancing resistor W to the emitter circuit. The two collectors of the transistors T and T are likewise connected to each other and also to the indicating instrument A which, in turn, is connected in the usual manner to the current source U. If required, a variable compensating resistor W may also be inserted into the output circuit for attaining the most suitable scale adjustment.
The transistors which so far have been found to be the most suitable for the apparatus according to the invention are junction transistors of the npn-type since they may withstand a higher load and therefore permit a higher amplification and also have a very low input resistance as compared with transistors of the pup-type. By connecting the two transistors T and T in opposition to each other, it is also possible to compensate for variations in voltage and temperature to which transistors are usually very susceptible, so that the high indicating accuracy of the apparatus will always remain constant. By means of the resistor W it is possible to determine the most suitable working point of the transistors, while the potentiometer S permits the input potentials on the emitters to be properly adjusted with respect to the output potentials on the collectors.
FIGURE 2 illustrates a circuit similar to that according to FIGURE 1, in which in place of a potentiometer two small current sources U and U are provided which are connected in series. The resistance R to be measured is connected at one side to the current source U and at the other side to the bases of the two transistors T and T rather than to the emitters as in the circuit according to FIGURE 1.
The emitters of the two transistors T and T are connected in parallel to the point of connection between the two current sources U and U and, if desired, fixed or variable resistors W and W may be inserted into this circuit. The collectors of the two transistors T and T are preferably connected in parallel through balancing resistors R and R to the indicating instrument A which is also connected in the usual manner to the current source U A moisture meter with a circuit according to FIGURE 2 has the same advantages as one with a circuit according to FIGURE 1. Of course, the apparatus is designed so as to permit the different resistors to be easily adjusted or exchanged in accordance with the size required for the particular measurements to be carried out.
FIGURE 3 illustrates a further transistor circuit according to the invention, in which a source of alternating current is employed in place of a direct-current source and in which the two transistors T and T are connected in series and produce a multistage amplification. The alternating current may be produced in any suitable manner, for example, by a small generator or by an oscillator or a transistorized direct-current converter. One pole of the second current source U consisting of a small battery is connected in the usual manner to the alternating-current source U The resistance R to be measured is connected to this alternating-current source U and also through a condenser F to the base of the transistor T In front of the condenser F a connecting line branches off to the collector of the transistor T and into this connecting line a fixed or variable damping resistor R is inserted. The emitter of the transistor T is further connected to the emitter of the second transistor T and the emitter of both transistors are connected to the connecting point between the two current sources U and U The collector of the transistor T is further connected through a coupling condenser F and parallel thereto through a variable coupling resistor R to the base of the transistor T In parallel connection to the latter there are also a resistor R; and a transformer U, both of which are connected at one side to the current source U By means of the transformer U the measuring current is transmitted in the usual manner to the indicating instrument through a pair of rectifiers. This circuit arrangement also permits high resistances or the corresponding conductances as occur in moisture and insulation measurements to be measured and indicated very quickly, accurately, and reliably.
Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the appended claims.
Having thus fully disclosed my invention, what I claim 1. A measuring instrument for indicating the moisture content of solid materials by measuring the electric resistance thereof by means of measuring electrodes applied upon or inserted into the material, comprising a measuring circuit, an indicating instrument, a current source coupled to said measuring circuit and said indicating instrument, said measuring circuit including at least two transistors interconnected to operate as amplifiers and connected between said measuring electrodes and said indicating instrument, means for coupling said measuring electrodes across the base-emitter of at least one of said transistors, and variable impedance means operatively interconnected between said transistors for separately controlling the bias applied to the base of at least one transistor relative to the other for adjusting current flow through one of the transistors relative to current flow through the remaining transistor to compensate for variations in temperature and supply voltage whereby an accurate linear measurement of moisture content is obtained over a relatively large measuring range.
2. A measuring instrument as defined in claim 1, in which said two transistors are connected symmetrically in parallel circuit relationship in opposition to each other.
3. A measuring instrument as defined inclaim 1, in which said transistors are connected in series circuit relationship relative to each other in a cascade connection.
4. A measuring instrument as defined in claim 1, in which said transistors are of the npn-type.
5. A measuring instrument as defined in claim 1, further comprising means for connecting the resistance to be measured at one side to said current source and at the other side in parallel to the emitters of said two transistors, a balancing resistor, means for connecting the emitters of said transistors through said balancing resistor to the bases of said transistors, a variable potentiometer, means for connecting said transistors through said potentiometer to said current source, means for conmeeting the collectors of said transistors to each other, and means for connecting said collectors to said indicating instrument.
6. A measuring instrument as defined in claim 5, further comprising a line connecting the emitters of said two transistors to each other, at least one coupling resistor inserted into said connecting line, a compensating resistor, and means for connecting said compensating resistor between the collectors of said transistors andsaid indicating instrument.
7. A measuring instrument as defined in claim 1, further comprising means for connecting the resistance to be measured at one side to said current source and at the other side to the bases of said two transistors,
which are connected in parallel, a second current source, a line connecting one side of said second current source to one side of said first current source, means for connecting the emitters of said transistors to said currentsource connecting line, lines connecting the collectors of said transistors in parallel to said indicating instrument.
8. A measuring instrument as defined in claim 7, further comprising a line connecting the emitters of said two transistors to each other, compensating resistors connected into said emitter connecting line, and balancing resistors connected into said collector connecting line.
9. A measuring instrument as defined in claim 1, in which said current source comprises a first direct current source and a second alternating current source, each connected at one side to the other, and wherein the measuring instrument further comprises a first and a second condenser, a damping resistor, a coupling resistor, a further resistor, a transformer, a resetting resistance means for connecting the resistance to be measured at one side to said alternating current source and at the other side in parallel through said first condenser to the base of the first of said transistors and through said damping resistor to the collector of said first transistor, means for connecting the emitters of said two transistors to each other and also to both of said current sources, means for con meeting the base of the second transistor through said coupling resistor and said second condenser in parallel with said coupling resistor to the collector of said first transistor, means for connecting the collectors of the first and second transistors through said further resistor and through said transformer to said second current source, said transformer lying parallel to said resetting resistance, and rectifying means connecting said transformer to said indicating instrument.
(References on following page) References Cited UNITED STATES PATENTS Marco et a1. 32462 Sziklai et a1. 33013 Houck 33013 Mead 32465 Kemelhor et a1. 324-62 Giger 330-12 6 3,197,697 7/ 1965 McCauley 324-62 FOREIGN PATENTS 900,194 7/ 1962 Great Britain.
WALTER L. CARLSON, Primary Examiner.
W. H. BUCKLER, E. E. KUBASIEWICZ,


The increasing penetration of distributed power generation into the power system leads to a continuous evolution of grid interconnection requirements. In particular, active power control will play an important role both during grid faults (low-voltage ride-through capability and, controlled current injection) and in normal conditions (reserve function and frequency regulation). The aim of this paper is to propose a flexible active power control based on a fast current controller and a reconfigurable reference current selector. Several strategies to select the current reference are studied and compared using experimental results that are obtained, during an unsymmetrical voltage fault. The results of the analysis allow selection of the best reference current in every condition. The proposed methods facilitate multiple choices for fault ride through by simply changing the reference selection criteria.
|Titolo:||Flexible active power control of distributed power generation systems during grid faults|
|Data di pubblicazione:||2007|
|Digital Object Identifier (DOI):||10.1109/TIE.2007.899914|
|Appare nelle tipologie:||1.1 Articolo in rivista|


Control your environment
Information about DUST
Article number: DUST V2
- Can monitor TSP (Total Suspended Particulate), PM 10, PM 2.5 or PM 1
- Constant wireless data transfer to Honeycomb via 4G/LTE or WiFi
- Suitable for rough environments
A certified monitoring device
The DUST air quality monitor is MCERTS-certified, meaning that it complies with the Quality and Performance Standards for Environmental Data Management Software established by the Environmental Agency of England & Wales. Since MCERTS is based on international standards itself, you can rest assured that the DUST air quality unit meets your regional quality requirements for monitoring devices.
✅ CE approved
✅ FCC international guidelines
✅ Low Voltage Directive
Suitable for multiple purposes
With the DUST monitor, you can monitor TSP (Total Suspended Particulate), PM 10, PM 2.5 or PM 1. The DUST unit comes with a PM 10 cyclone, but you can easily exchange it for cyclones suitable for smaller particle sizes. Our DUST unit helps you keep your on-site personnel safe by monitoring a major risk factor at construction sites and waste facilities.
Efficient solution for the management of dust measurements
Just like our SWARM vibration monitor, the DUST unit is connected to the Honeycomb platform. Through it, you can remotely configure, view and manage your dust and vibration monitoring projects, create custom views and export the collected data. In short, environmental monitoring just got a lot simpler and more efficient.
An air quality monitor designed for rough environments
The DUST monitor was designed for outdoor use and can be used even in the roughest environment. You can use the DUST air quality sensor for particulate matter monitoring and dust emission simulation in the following environments:
- Construction, excavation, demolition, mining and more;
- Recycling and waste facilities.


A new twist to 3-D imaging technology could enable people to use a self-driving car to spot their kid half a block away, answer their smartphone across a room with the wave of their hand, and many more.
The new system, developed by researchers at the University of California, Berkeley, can remotely sense objects across distances as long as 30 feet, 10 times farther than what could be done with comparable current low-power laser systems.
With further development, the technology could be used to make smaller, cheaper 3-D imaging systems that offer exceptional range for potential use in self-driving cars, smartphones and interactive video games like Microsoft's Kinect, all without the need for big, bulky boxes of electronics or optics.
The new system relies on LIDAR ("light radar"), a 3-D imaging technology that uses light to provide feedback about the world around it. LIDAR systems of this type emit laser light that hits an object, and then can tell how far away that object is by measuring changes in the light frequency that is reflected back.
It can be used to help self-driving cars avoid obstacles halfway down the street, or to help video games tell when you are jumping, pumping your fists or swinging a "racket" at an imaginary tennis ball across an imaginary court.
In their new system, the team used a type of LIDAR called frequency-modulated continuous-wave (FMCW) LIDAR, which they felt would ensure their imager had good resolution with lower power consumption, Behroozpour says.
This type of system emits "frequency-chirped" laser light (that is, whose frequency is either increasing or decreasing) on an object and then measures changes in the light frequency that is reflected back. (ANI)


Reliable separations of organic and inorganic anions
PRP-X100: Anion Exchange HPLC Column
High capacity ion exchange chromatography of organic and inorganic anions, organic acids, organic and inorganic arsenic species, halides, nucleotides.
Hamilton PRP-X100 and PRP-X110 are highly stable, inert materials. The PRP-X100 can be used with virtually any HPLC or ion chromatograph, including dedicated IC units. Technological advancements in modern polymer chemistry now deliver a more rugged column with exceptionally higher separation efficiencies than earlier predecessors. PRP-X100 and PRP-X110 columns are well suited for use in systems employing suppressed/non-suppressed conductivity, electrochemical, UV, and ICP-MS detection. Chromatographers currently using wet chemical or colorimetric methods will find ion chromatography greatly reduces sample pretreatment and improves the accuracy and precision of results.
In anion exchange chromatography, the stationary bed has an ionically positive (+) charged surface while the sample ions are of negative (-) charge. The stronger the negative charge on the sample, the stronger it will be attracted to the positive charge on the stationary phase.
Anion Exchange Capacity
Anion exchange capacity is a measurement of the number of negative charges (anions) that the exchange resin can bind to and is reported in singly charged ion equivalents per 1 gram of resin. Exchange capacity is dependent upon the pH of the mobile phase and in anion exchange chromatography; as mobile phase acidity decreases (pH increases), the exchange capacity decreases.
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Flaw detection and wall thickness measurement of damping materials
Testing of plates, blocks, cast and forged parts as well as plastics
Detection of delamination etc.
The ergonomic straight beam probes of the SONOSCAN Series for Nondestructive Testing (NDT) comply with the European Standard DIN EN 12668-2. Our ultrasonic transducers are used to check metals, plastics and ceramic materials for discontinuities, such as cracks, inclusions, blowholes and other material flaws.
|SONOSCAN PXS10||Ø 6 mm||10 MHz||Microdot|
|SONOSCAN PXS15||Ø 5 mm||15 MHz||Microdot|
|SONOSCAN PS2 EN||Ø 10 mm||2 MHz||LEMO 00|
|SONOSCAN PS4 EN||Ø 10 mm||4 MHz||LEMO 00|
|SONOSCAN PL1 EN||Ø 24 mm||1 MHz||LEMO 1S|
|SONOSCAN PL2 EN||Ø 24 mm||2 MHz||LEMO 1S|
|SONOSCAN PL4 EN||Ø 24 mm||4 MHz||LEMO 1S|
|SONOSCAN PS2i EN||Ø 10 m||2 MHz||LEMO 00|
|SONOSCAN PXS10i EN||Ø 8 mm||10 MHz||Microdot|
* SONO-ID tag for intelligent probe recognition and data memory via SONOWALL 70


The XL-WP4 is a universal, 66 W in-line AC-to-DC power supply XLR 4-pin DC connector with detachable IEC power cord. 100–240, 50/60 Hz.
The XL-WP4 converts AC wall power to DC power for your recording devices through an XLR4-F connector. Like with most power bricks, the IEC wall power cord detaches for easier storage.
The XL-WP4 is included with the Sound Devices 970, PIX 260i, and PIX 250i, and can be used to power any device with an XLR4M power input, like the Audio Limited A10-Rack.
[email protected] (212) 629-9430[email protected] (404) 855-2255


Click on image for PDF version of poster
Poster presented at the 42nd Lunar and Planetary Science Conference by A. Epps, M. Sandler
"The goal of the Lunar Orbiter Image Recovery Project (LOIRP) is to digitize and archive the magnetic tape records generated by the five Lunar Orbiter spacecraft in the mid-1960s. The readout scanners utilized onboard the Lunar Orbiter spacecraft employed a phosphor-covered anode bombarded by an electron beam to focus a spot of light on 70mm film developed onboard the spacecraft. This light was modulated by the density of the image and read by a photomultiplier tube. Each individual pass of this scanning procedure across the 70mm film produced a thin strip of a larger image, referred to as a "framelet". The product of the spacecraft's readout system was a video waveform that was modulated and transmitted to three DSIF stations and recorded onto 2-inch magnetic tape via Ampex FR-900 data recorders. This document discusses the process by which these video signals were converted into digital images."


Motors – AC, DC play a pivotal role in powering numerous devices and machinery we encounter daily. Motors are the driving force behind these technological marvels, from electric vehicles to industrial machinery.
AC stands for Alternating Current, while DC stands for Direct Current. These terms refer to the electrical current used to power the motor. AC motors run on alternating current, where the direction of the current periodically changes, while DC motors run on direct current, where the current flows consistently in one direction.
AC motors are used in industrial applications due to their efficiency, reliability, and ability to operate at varying speeds. They are categorized into two main types: synchronous and asynchronous motors. DC motors operate using direct current, making them particularly useful in applications requiring precise speed control and torque. These motors utilize a magnetic field generated by the direct current to produce rotational motion. DC motors can be further classified into brushed and brushless motors.
Synchronous AC motors are designed to rotate at a constant speed, synchronizing with the frequency of the alternating current power supply. These motors are ideal for applications that require precision, such as clocks, timers, and robotics. They are also commonly found in power plants, where they help generate electricity.
The synchronization of a synchronous AC motor is a critical aspect of its operation. The magnetic field created by the rotor must exactly align with the revolving magnetic field produced by the stator. This synchronization ensures that the rotor rotates at the desired speed, matching the frequency of the AC power supply. It allows for precise control over the motor’s speed and makes synchronous AC motors well-suited for applications that require constant rotational speed.
Asynchronous AC motors, or induction motors, are the workhorses of industrial applications. They operate slightly slower than synchronous motors and are highly versatile. Induction motors are widely used in various industries, including manufacturing, HVAC systems, and appliances like refrigerators and washing machines.
An important feature of asynchronous AC motors is that they can function without requiring the rotating magnetic field and the rotor to be synchronized. This is achieved through induction, where the rotor currents are induced by the rotating magnetic field of the stator. As a result, the rotor rotates at a slightly slower speed than the rotating magnetic field, creating what is known as slip. This slip allows the motor to generate torque and overcome the inertia of the connected load.
Brushed DC motors have been a cornerstone of electrical engineering, driving countless devices and machinery with their simplicity and cost-effectiveness. They find applications in small appliances, power tools, and automotive systems.
Brushed DC motors rely on the interaction between the magnetic field and an electric current to generate rotational motion. They consist of a rotor, a stator, brushes, and a commutator. When electrical current passes through the windings of the rotor, it generates a magnetic field. In conjunction with the brushes, the commutator ensures the continuous flow of current and the reversal of the magnetic field, allowing the rotor to rotate.
Brushless DC motors have gained significant popularity due to their efficiency and durability. Unlike brushed motors, they use electronic commutation to eliminate the need for brushes and commutators. This technology enhances motor performance, reduces maintenance requirements, and enables precise control. Brushless DC motors are found in electric vehicles, drones, and high-precision industrial machinery.
Brushless DC motors can provide greater power outputs while being smaller and lighter than brushed DC motors. Eliminating brushes reduces wear and tear, resulting in longer motor life and reduced maintenance requirements.
One of the considerations when using brushless DC motors is the requirement for electronic control systems. These motors require dedicated electronic controllers to energize the stator windings in the correct sequence precisely. The electronic control system adds complexity and cost to the overall motor system but provides enhanced control and performance benefits.
Tormeka is the premier distributor of AC and DC motors in Europe. Tormeka offers a comprehensive range of AC and DC motor solutions and electronic components in Europe. At Tormeka, we provide exceptional customer service and support with all available products.
FAQs About AC, DC Motors
A: AC motors operate on alternating current, while DC motors run on direct current. AC motors are known for their ability to vary speeds, while DC motors offer precise speed control and torque.
A: AC motors find applications in various industries, including power generation, manufacturing, and appliances like refrigerators and washing machines.
A: DC motors use direct current to generate a magnetic field, producing rotational motion. This mechanism enables precise speed control and torque.
A: Yes, brushless DC motors are more efficient and durable than brushed DC motors. They eliminate the need for brushes, reducing maintenance requirements and improving overall performance.
A: Brushless DC motors find extensive application in electric vehicles, drones, and high-precision industrial machinery where there is a need for accurate speed regulation and long-lasting performance.
A: AC motors can vary in speed and are generally more cost-effective for applications that don’t require precise speed control. They are also suitable for long-distance power transmission.
A: Synchronous AC motors achieve synchronization by the interplay between the rotating magnetic field by the stator and the permanent magnets installed on the rotor.
A: Asynchronous AC motors achieve rotation through induction. The magnetic field generated by the stator causes currents to be induced in the rotor, creating another magnetic field that rotates. The interaction between these magnetic fields generates rotational motion.
A: Brushless DC motors offer higher efficiency, greater power density, enhanced reliability, and smoother control than brushed DC motors. They also eliminate the need for brushes, reducing maintenance requirements and improving overall motor life.
Motors – AC, DC are the powerhouses behind modern technology, driving our world forward with remarkable capabilities. AC motors excel in industrial applications, offering efficiency and versatility, while DC motors provide precise speed control and torque, making them indispensable in numerous fields. Contact us if you want to power up your machinery with reliable AC and DC motors. At Tormeka, our professionals are committed to delivering top-notch products and exceptional customer assistance. Remember Tormeka for all kinds of electronic components needs.


Rs13100 wireless MCU is an ultra-low power dual-mode SOC device that supports Bluetooth 5 and 802.15.4 technology and can run ZigBee or thread protocol. It can provide necessary connection options and processing capabilities for audio, data transmission, positioning and control applications. It is an ideal solution for the markets of wearable devices, home automation, industrial automation, lighting and household appliances.
Rs13100 SOC device has arm cortex m4f with performance up to 180mhz, maximum 4MB special flash memory and 400KB ram, which can handle very demanding operation smoothly and efficiently. In order to create a highly secure system, rs13100 includes multiple layers of security, including physical non cloning function (PUF), encryption hardware accelerator, secure boot and secure zone.
The low-power Bluetooth 5 long-distance data rate of rs13100 device is 125kbps, the high data rate is 2Mbps, and has the advertising expansion function to ensure high connectivity. This SOC has advanced RF performance, low-power Bluetooth and 802.15.4, with output power up to 20dbm, providing long-distance wireless connection and higher throughput. With the integrated wireless stack and profile, customers can easily integrate and profile the rs13100.
The dimensions of rs13100 devices are only 3.51mm x 3.60mm (SOC) and 4.63mm x 7.90mm (module), with ultra-small overall dimensions. Customers can visit www.rutronik24.com com. Cn for other packaging options. The device has unique peripherals such as ULP subsystem, voice activity detection (VAD) and up to eight capacitive touch sensor inputs.


RELIABILITY OF RESEARCH INSTRUMENTS
Instrument reliability is a way of ensuring that any instrument used for measuring experimental variables gives the same results every time.
In the physical sciences, the term is self-explanatory, and it is a matter of making sure that every piece of hardware, from a mass spectrometer to a set of weighing scales, is properly calibrated.
Instruments in Research
As an example, a researcher will always test the instrument reliability of weighing scales with a set of calibration weights, ensuring that the results given are within an acceptable margin of error.
Some of the highly accurate balances can give false results if they are not placed upon a completely level surface, so this calibration process is the best way to avoid this.
In the non-physical sciences, the definition of an instrument is much broader, encompassing everything from a set of survey questions to an intelligence test. A survey to measure reading ability in children must produce reliable and consistent results if it is to be taken seriously.
Internal consistency is usually measured with Cronbach’s alpha, a statistic calculated from the pairwise correlations between items. Internal consistency ranges between negative infinity and one. Coefficient alpha will be negative whenever there is greater within-subject variability than between-subject variability.
A commonly accepted rule of thumb for describing internal consistency is
|Cronbach’s alpha||Internal consistency|
|α ≥ 0.9||Excellent|
|0.9 > α ≥ 0.8||Good|
|0.8 > α ≥ 0.7||Acceptable|
|0.7 > α ≥ 0.6||Questionable|
|0.6 > α ≥ 0.5||Poor|
|0.5 > α||Unacceptable|
INTERNAL CONSISTENCY RELIABILITY:
Internal consistency reliability defines the consistency of the results delivered in a test, ensuring that the various items measuring the different constructs deliver consistent scores.
For example:- an English test is divided into vocabulary, spelling, punctuation and grammar. The internal consistency reliability test provides a measure that each of these particular aptitudes is measured correctly and reliably.


Ducking is a popular technique used in EDM music to apply percussive processing to pads, leads, and bass lines using side-chains on compressors. This technique is also used as a method for getting bass and drum passages to subtly fit together in mixes. In order to successfully apply ducking to your track you must have the following:
- Compressor inserted on a pad or lead track with side-chain capabilities
- Percussive source to key the side-chain
First, grab a kick drum sample and align it to the desirable rhythm you need. Next, insert a compressor onto your synth lead or pad track. Afterwards insert a send on the sampled kick drum track and set the send to “Pre-fader”. In SONAR, deselecting the [Post] button enables pre-fader sends. Mute the kick drum sample and turn up the gain on the send.
Once you have the signal flow set, enable the Sidechain on the Compressor. Now, every time the kick drum sample plays the Side-Chain will trigger the compressor and “Duck” the signal. You can set the compressor using the Threshold, Attack, and Release settings to shape the kind of effect you want.
Try it yourself with the SONAR X2 Producer free 30-Day trial.


3D printing is a diverse field, in particular for biological or bioengineering applications. As a result, research teams working in this area are often multidisciplinary. A (bio) 3D printer in this research environment should balance performance with ease of use in order to enable system adjustments and operation for all machine users from a wide range of disciplines. This work presents results in the development of an easy-to-use fabrication system capable of producing rectilinear bone scaffolds. Common motion control problems, which are barriers to ease of use, are addressed and implemented in a way that researchers outside of the controls field could easily understand. A dynamic model of a 3-stage position system for bone scaffold fabrication is presented. Further, control design for a feedforward plus feedback controller and a user-friendly ILC feedforward compensator is outlined. The ability of the (bio) 3D printer to print bone scaffolds and the effectiveness of the control architecture is demonstrated.


Nigeria N0.1 online Medical Equipment store
Mini Dry Bath Incubator fits conveniently on every bench with its very small footprint. The digital microprocessor ensures temperature accuracy of the metal block and quick heating saves your valuable time. This small but powerful unit is suitable for a range of applications: Restriction digests, denaturing DNA, NUB, melting agar, coagulation studies, in-situ hybridisation, and Hot Start thermocycler reactions. The unit is supplied with a transparent lid for temperature uniformity across all tubes.


How Communities & Businesses Are Using Air Quality Technology During Wildfires
Do you know how many wildfires happen in the US each year?
According to the EPA, there are an average of 70,000 wildfires—and that’s just one country. All over the world, many communities are experiencing longer and harsher fire seasons and the harsh impacts of reduced air quality for extended periods of time.
Thankfully, air quality monitoring is helping these communities better monitor their air pollution.
In today’s blog, we’re looking at how new, affordable, and highly precise air quality monitors have become available for anyone to use. Then, we’ll look at real-life examples where businesses have been using these air quality monitors for all kinds of projects.
The Rise of Low-Cost Air Quality Monitors
Air quality monitoring has been taking place since the early days of coal mining when they used canaries to detect air quality. When air quality monitoring became more prevalent in big cities, the monitors were bulky, expensive, and not always that accurate.
In the last several years, air quality monitors have become more affordable, therefore, more accessible. More community scientists are getting involved in air quality research with the help of PurpleAir air quality monitors or using our air quality data.
For example, our PurpleAir Zen is the latest air quality monitor designed to give you peace of mind—whether you’re using it for your home, office, or research project.
PurpleAir Zen Monitor
If you live in an area prone to wildfires, you want as much warning as you can get. The PurpleAir Zen is our latest air quality monitor measuring real-time PM2.5 concentrations. And it’s not just for individual use, each air quality monitor owned by a local business or community member helps contribute to the available data on our PurpleAir Map.
Some other features include:
- Built in full color LED ring so it’s easy to see your air quality across the room based on the color of the light, as well as a tap sensor to adjust the brightness.
- Versatile mounting hardware so it can be used indoors and out with the included desktop or wall (or pole) mount.
- Pressure, Temperature, Humidity & Gas Sensor which is also helpful for people who connect PurpleAir monitors to their home automation apps.
- Built-in SD card which allows you to log information for offline data capture.
- WiFi connectivity so that data is stored in the cloud and added to the PurpleAir Map in real time.
The PurpleAir Map is a web application that displays a network of community-owned, PurpleAir sensors which each upload data to the PurpleAir map in real time. With the PurpleAir Map, anyone can see their city’s air quality in real-time.
Community members can also easily download historical air quality data for research projects.
How Businesses Are Using PurpleAir During Wildfire Season
Today, there are plenty of new solutions to seeing your air quality, and PurpleAir is just one of them. Even National Geographic reported on how more residential monitors are being used to help fire-struck communities.
In 2020, a group of academic researchers in Los Angeles also wondered how the city of LA could better monitor particulate matter in local neighborhoods hourly. Historically, the challenge in getting this information was that government air quality monitors were too sparse and residential air quality monitors were too costly or inaccurate.
However, with the increased use and affordability of air quality monitors like PurpleAir, they found they could gain better up-to-date data when used in combination with local monitoring systems used by other agencies. Additionally, they concluded that the increased use of PurpleAir monitors was a giant step towards empowering community scientists.
This type of community involvement also has the potential to have a positive impact on emergency services during wildfires. For example, firefighters used PurpleAir monitors during wildfires to determine where to set up temporary monitoring for particulate matter. This gave them more insight into the air quality during wildfires in real-time, giving them better data to make informed safety decisions for local communities.
We hope more cities and communities are inspired to invest in air quality technology or using the PurpleAir Map to see their city’s air quality in real-time.
Connect With PurpleAir
At PurpleAir, there are tons of organizations around the world using our data—from Google to the EPA. We’re thrilled to see research projects like this, and we look forward to seeing plenty more in the future.
Are you a technology company or institution looking to work with PurpleAir?


Measurement of adhesive properties by nanoindentation
Adhesion properties are becoming very important in industrial and academic research domains such as in electronics or soft materials. The current status of development now allows for manufacturing of such adhesive layers or films that are used for attachment of electronic components to each other or for attachment of protective coating. These layers are usually very thin and their testing requires new techniques. Nanoindentation, used as a characterization tool for simultaneous measurement of local mechanical properties and adhesion at the microscale, is one of these new techniques. This application report presents several applications of nanoindentation for measurements of adhesive properties at the microscale and discusses the challenges associated with these measurements.
Adhesion properties of surfaces, should it be a desired property or not, can be an indicator of surface preparation (cleanliness, wettability, polymerization state, etc.). Surface adhesion is of particular interest when developing adhesive joints, sealing or depositing protective or decorative layers. Adhesion of a surface coating on a substrate is commonly measured by scratch tests, while adhesive properties of the top surface are often measured by “Tack” testing. Nanoindentation method is however a perfect candidate to measure adhesive properties of a surface at the same time as determining the mechanical properties of thin films. In this application report, nanoindentation as a tool for measurement of surface adhesion of soft and sticky films and materials will be presented. Recently we have seen a large interest in measurement of adhesive properties of many materials, including mainly packaging and various electronic components. One of the dominant applications in this field are optically clear adhesives (OCA). The OCAs have become very important in production of mobile phones since the introduction of smartphones with large touchscreens. To determine the adhesive properties together with the mechanical properties of this adhesive film, very few methods are currently available. Nanoindentation is considered as one of the candidates for the simultaneous measurement of adhesive properties and of mechanical properties. Both these properties can depend on temperature, ultraviolet radiation and time and it is therefore important to test the different types of the OCA films.
This application report presents the nanoindentation method for simultaneous measurements of adhesive forces and mechanical properties on various materials. A short introduction to the theory of adhesion is followed by showing typical adhesion measurements on soft materials and OCA films.
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The F37’s simple operational features provide an easy and smooth workflow. The necessary controls for routine examinations are intuitively laid out, with high priority on reducing the examiner's operation steps. Imaging features inherited from higher-class models provide a work environment for concentrated examinations.
SOFIA offers a fully automated scan procedure providing rapid whole breast image acquisition with one button operation. Patients can be scheduled every 10 minutes for a bilateral breast examination. This automated process does not require operator interaction during the scanning procedure, ensuring reproducibility and efficiency.


This is the phenomena of absorption, and the extent of absorption is directly proportional to the amount of atoms present, in other words, the concentration aas schematic diagram description – 1 hollow cathode lamp 2. Overhead rates and absorption versus variable costing november 2, 2012 editor uploads accounting & markets 0 applying overhead to work in process in the second instalment of student notes (‘cost concepts, categories and flows’) i mentioned that manufacturing overhead costs are applied (or allocated) to products by using overhead rates. Cookbookdoc, 9/10/96 1:41 pm safety information the analytical methods section describes methodologies using a wide variety of potentially hazardous chemicals (acids, bases, organic. Analysis and optimization of double effect parallel flow type absorption chiller and suggested that the system operation is safe when the sdr is close to 05 wang et al  have presented analysis of gas-fired air-cooled parallel flow.
Absorption bing dainties the costs of all fabrication constituents ( direct stuff, direct labor, variable operating expense and fixed operating expense ) as inventoriable or merchandise costs in conformity with by and large accepted accounting rules ( gaap ) , ( barfield et al , 2001 ) 12 fringy costing variable costing is a [. The difference between marginal costing and absorption costing is a little complicated in marginal costing, product related costs will include only variable cost while in case of absorption costing, fixed cost is also included in product related cost apart from variable cost. Infrared spectroscopy and mass spectrometry introduction elemental analysis is destructive, whereas nmr is non-destructive - you can vibrations of bonds with dipole moments normally result in the absorption of ir radiation, and are said to be ir active ch12 ir and ms page6.
Compare it with the c=c in the previous case which are weaker and sharper the characteristic absorption of the alcohol, 2-propanol, is the broad band due to the hydrogen bonded -oh group carboxylic acids contain both c=o and oh groups. Microscale experiments in organic chemistry worksheet lab 2-1 infrared spectroscopy (ir) worksheet 1 record the number of your unknown 2 prepare a spectrum of your unknown and attach the spectrum to this report form. Emission absorption spectra description emission is the ability of a substance to give off light, when it interacts with heat absorption is the opposite of emission, where energy, light or radiation is absorbed by the electrons of a particular matter. In 1920, sir ronald a fisher invented a statistical way to compare data sets fisher called his method the analysis of variance, which was later dubbed an anova this method eventually evolved into six sigma data set comparisons the f ratio is the probability information produced by an anova it.
Review problem 1: contrasting variable and absorption costing dexter corporation produces and sells a single product, a wooden hand loom for weaving small items such as scarves. The quantitative analysis of glass by atomic absorption spectroscopy, forensic science (1976) 8:217–227 hurlbut, c s jr and klein, c manual of mineralogy (after james d dana) 19th ed. Comparison between single beam and double beam atomic absorption spectrometer systems spectroscopic analysis has seen growth in a number of application oriented domains such as uv – visible, infrared, raman, atomic absorption spectroscopy, etc.
The basic difference between absorption costing and marginal costing lies in how fixed overhead cost is treated in management decisions of valuation of inventory and pricing in absorption costing, fixed cost is included in both value of inventory and cost of the product when making the pricing decision whereas marginal costing avoids fixed. From sample handling and analysis to the communication of test results with tens of thousands of installations worldwide, perkinelmer systems are performing inorganic analyses every hour of every day. Absorption vs variable costing – in the field of accounting, direct costing and full costing are two different methods of applying production costs to products or services the difference between the two methods is in the treatment of fixed manufacturing overhead costs.
9: marginal and absorption costing 227 2 the principles of marginal costing the principles of marginal costing are as follows (a) period fixed costs are the same, for any volume of sales and production (provided that the level of activity is within the 'relevant range'. Let us know use these basic principles to account for and compare spectra produced by different types of astronomical objects stellar spectra the spectrum below is an intensity plot of a star. The corrected absorption value is called molar absorptivity, and is particularly useful when comparing the spectra of different compounds and determining the relative strength of light absorbing functions (chromophores.
Comparing caco-2 and mdck permeability for oral absorption estimations (version 16110) were used for regression analysis and significance testing the study compared the permeability of. Atomic absorption spectrometers use particular wavelengths of light to evaluate the concentration of gas-phase atoms in a liquid or solid sample after a solid sample is dissolved in a liquid or a liquid sample is diluted, the resulting sample is tested. Absorption costing is a method in which cost of units produced is calculated as the sum of both the variable manufacturing costs incurred and the fixed manufacturing costs allocated to those units it is also called full absorption costing or full costing.


Well stimulation is a highly technical and precise method where high pressure water and sand is used to crack a rock formation deep underground.
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With its DTS technology, LIOS WELL.DONE is ideally suited as a reliable solution to help operators increase productivity through real-time measurements. The system enables accurate diagnostics and help monitor completion integrity by identifying unstable flow without interrupting production. Management of wells require continuous real-time monitoring for optimal economic and operational performance and with the optical fiber cable in LIOS WELL.DONE no area will be unmonitored.
Our advanced visualization software delivers information directly at the operator’s desk providing option for full analysis of reservoir workflows. The technology in LIOS WELL.DONE has excellent spatial resolution providing a very accurate and precise picture of where potential actions need to be taken. It is possible to acquire data from multiple wells and thereby obtain an overall perspective for further optimization and potential cost-savings.


To run its leading scientific research program in superconducting RF and state-of-the-art cryomodule production activities, the Applied Physics and Superconducting Technology Directorate (APS-TD) maintains comprehensive SRF capabilities that include full life-cycle treatment of cavities and cryomodules, from design through to production. The world-class facilities and wide spectrum of expertise are described in the following sections:
- Vertical Testing of Cavities
- Horizontal Testing of Cavities
- Cavity Surface Processing
- Cavity Post-Processing
- Cavity String and Cryomodule Assembly
- RF Design and Test
- Cryomodule Engineering
- Optical Inspection and Eddy Current Scanning
- Material Studies
Vertical Testing of Cavities
Fermilab’s SRF Vertical Test Stand Facility encompasses three large liquid helium dewars, each of which can test multiple production-style cavities simultaneously. The RF control system is capable of high power operation over a wide frequency range, and the cryogenic system can cool liquid helium baths as low as 1.4 K. Advanced diagnostic equipment includes second sound quench detection system, temperature mapping system for single cell cavities, and externally controlled magnetic field environment.
Horizontal Testing of Cavities
After a cavity treatment has been qualified in vertical test, it may then be evaluated in the Horizontal Test Facility (HTF), to make sure that it works well with all auxiliary components to achieve the required performance. In preparation for hoizontal test, the cavity is equipped with additional components such as tuners which maintain the cavity at the desired operating frequency, high power couplers that are used to power the cavity, and other ancillary systems that are needed to ensure the cavity will perform well in the accelerator. Fermilab has established three test stands at the HTF designed to test different types of accelerating cavities.
Cavity Surface Processing
High quality polishing is essential to deliver maximum accelerating gradients and high quality factors in SRF cavities. Chemical processing of superconducting cavities is mainly used to remove contaminants from the Niobium surface. Fermilab capabilities include electropolishing (EP), buffered chemical polishing (BCP), and centrifugal barrel polishing (BCP) for a wide variety of cavity types. Surface processing facilities are located in the Cavity Processing Lab in IB4 and the joint cavity surface processing facility at Argonne National Laboratory.
Heat Treatment Facilities
Two high temperature vacuum furnaces and two low temperature ovens are used to perform heat treatments on SRF cavities. A major focus is to develop and optimize recipes and create new Niobium (Nb) compounds aimed at reducing RF losses in the cavities which can dramatically reduce operating costs. Other important applications of heat treatment are hydrogen degasification, annealing, and mild baking to remove high field Q-slope.
Class 100 Clean Rooms
SRF cavity cleanroom assembly capability is essential to good cavity performance. Fermilab clean rooms contain automated high-pressure rinsing tools used for cleaning the interior surface of cavities. They are also used to assemble cavities and pump them down to ultra high vacuum. Cleanroom facilites are located in IB4, Lab 2, and the joint cavity surface processing facility at Argonne National Laboratory.
Cavity String and Cryomodule Assembly
APS-TD has two independent cavity string assembly facilities, located in MP9 (the largest cleanroom at Fermilab, ~250 m2) and Lab 2. Each contain cleanroom areas with several levels of cleanliness:
- Class 1000 (ISO6) ante cleanroom area: Preparation of the dressed cavities for transportation into the assembly cleanroom.
- Class 100 (ISO5) sluice area: Parts and Fixtures final preparation to enter the Class 10 assembly area.
- Class 10 (ISO4) assembly cleanroom area: Where the cavity vacuum is vented to interconnect them with bellows.
Production floor areas for cryomodule assembly are located in ICB and Lab 2.
RF Design and Test
The central part of any particle accelerator is accelerating structure or RF cavity. Successful operation of cavities requires optimized design, precise production, and low power RF tuning. We have tools for providing superior design, precise measurements and tuning of accelerating cavities both for prototyping and production. The simulations codes HFSS, COMSOL, CST and ANSYS are installed in specialized TD servers to allow us to increase design efficiency, performing advanced analysis for optimized cavity design. Optimization includes reducing peak surface fields, multipactor mitigation, higher order modes extraction and damping, microphonics sensitivity, Lorentz force detuning minimization, structural and thermal stability analysis, and study of multipole effects of the beam.
Our sophisticated RF measurement equipment and tuning tools allow us to work with different type of RF cavities in wide frequency range. We are responsible of RF testing and quality control on all received cavities from vendors along the process of qualifying them for cryomodule operation. This includes monitoring key cavity performance parameters such as frequency spectrum, field flatness, eccentricity and physical length.
Cryomodules are the vacuum-insulated assemblies of superconducting RF cavities and associated hardware, including instrumentation and often also a superconducting magnet package. Thus, a cryomodule is the fundamental building block of a superconducting RF accelerator. These complex assemblies provide numerous challenges to engineers and designers. The cryomodules provide support, precise alignment, and thermal and magnetic shielding for the dressed cavities, as well as feed-throughs from the outside environment to low temperatures for the RF power and instrumentation. The cryomodule must provide the required insulating and beam vacuum and provide robust support with minimal cavity vibration and good cavity alignment reliably with thermal cycling. The design provides for cooling of the RF cavities to superconducting temperatures and protects the helium and vacuum spaces including the RF cavity from exceeding allowable pressures. Design of cryomodules calls upon a wide range of mechanical, thermal, and electrical engineering skills and experience.
Optical Inspection & Eddy Current Scanning
The optical inspection system consists of a camera and lighting system mounted to a rod that is inserted into the cavity. It is used for routine inspection of cavities during the processing cycle as well as computer-aided close inspection of particular regions of interest. Eddy current scanning is used to examine niobium sheets prior to cavity fabrication to check for impurities.
A wide range of materials studies tools are used, including scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and electron backscatter diffraction (EBSD) capabilities, physical property measurement system (PPMS), Instron tensile testing, Keyence laser confocal microscopy, and surface topological replicas. Chemical treatment of samples is also a critical capability.


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Patent application title: Powertrain Control Based On Bearing Speed
Michael Tekletsion Berhan (Sylvania, OH, US)
IPC8 Class: AF16H6104FI
Class name: Data processing: vehicles, navigation, and relative location vehicle control, guidance, operation, or indication transmission control
Publication date: 2016-05-26
Patent application number: 20160146339
A speed sensor is integrated with a bearing of a transmission. The speed
sensor may sense rotation of a bearing cage using a proximity sensor or
may sense passage of the rolling elements themselves using an
acceleration sensor. The speed of the shaft supported by the bearing is
calculated from the speed sensor reading. The shaft speed may be used to
control a slipping clutch during a shift event. When the transmission is
in a fixed gear ratio, inconsistent speed sensor reading may indicate a
1. A vehicle comprising: a housing; a shaft; a bearing having a plurality
of rolling elements separating the shaft from the housing and configured
to transmit radial forces from the shaft to the housing and to translate
circumferentially as the shaft rotates to facilitate low friction
rotation of the shaft with respect to the housing; a controller; and a
sensor mounted on the housing and configured to transmit to the
controller a signal that varies in response to translation of the rolling
2. The vehicle of claim 1 further comprising a cage retaining the rolling elements.
3. The vehicle of claim 2 wherein the sensor is a proximity sensor.
4. The vehicle of claim 3 wherein the cage is formed from a non-metallic material and defines a number of teeth on one edge, the teeth having a metallic coating.
5. The vehicle of claim 3 wherein the cage comprises: a non-metallic frame; and one or more metallic inserts defining a number of teeth fixed to an edge of the frame.
6. The vehicle of claim 3 wherein the proximity sensor is a Hall effect sensor.
7. The vehicle of claim 1 wherein the sensor is an acceleration sensor.
8. The vehicle of claim 1 wherein the sensor is a load sensor.
9. The vehicle of claim 1 wherein the sensor is an acoustic emissions sensor.
10. The vehicle of claim 1 wherein the rolling elements are ball bearings.
11. The vehicle of claim 1 wherein the rolling elements are roller bearings.
12. The vehicle of claim 1 wherein the rolling elements are tapered roller bearings.
13. A transmission comprising: a housing; a shaft; a bearing having a plurality of rolling elements separating the shaft from the housing and configured to transmit radial forces from the shaft to the housing and to translate circumferentially as the shaft rotates; a controller; and a sensor embedded in a bearing race and configured to transmit a signal to the controller in response to the rolling elements translating past the sensor.
14. The transmission of claim 13 further comprising a clutch.
15. The transmission of claim 14 wherein the controller is programmed to: process the signal from the sensor to estimate a speed of the shaft; and adjust a torque capacity of the clutch based on the estimated speed.
16. The transmission of claim 15 wherein the controller is further programmed to set a flag indicating a possible pre-load issue if the estimated shaft speed differs from an expected shaft speed while the transmission is in a fixed gear ratio.
17. The transmission of claim 13 wherein the sensor is an acceleration sensor.
18. The transmission of claim 13 wherein the sensor is a load sensor.
19. The transmission of claim 13 wherein the sensor is an acoustic emissions sensor.
20. A method of controlling a transmission comprising: receiving a signal indicating passage of rolling bearing elements past a fixed location on a transmission housing; processing the signal to estimate a speed of a shaft supported by the bearing elements; and adjusting a torque capacity of a clutch based on the estimated speed.
21. The method of claim 20 further comprising: setting a flag indicating a possible pre-load issue if the estimated speed differs from an expected speed while the transmission is in a fixed gear ratio.
 This disclosure relates to the field of vehicle controls. More particularly, the disclosure pertains to control of a transmission system based on speed measurements of bearing elements such as rollers, balls, or cages.
 Many vehicles are used over a wide range of vehicle speeds, including both forward and reverse movement. Some types of engines, however, are capable of operating efficiently only within a narrow range of speeds. Consequently, transmissions capable of efficiently transmitting power at a variety of speed ratios are frequently employed. When the vehicle is at low speed, the transmission is usually operated at a high speed ratio such that it multiplies the engine torque for improved acceleration. At high vehicle speed, operating the transmission at a low speed ratio permits an engine speed associated with quiet, fuel efficient cruising. Typically, a transmission has a housing mounted to the vehicle structure, an input shaft driven by an engine crankshaft, and an output shaft driving the vehicle wheels, often via a differential assembly which permits the left and right wheel to rotate at slightly different speeds as the vehicle turns.
 In many automatic transmissions, the power flow paths associated with various speed ratios are established by engaging a subset of the available clutches and brakes. Typically, the clutches and brakes are engaged by providing fluid at a controlled pressure to a clutch apply chamber. The fluid pressure forces a piston which in turn compressed a clutch pack of alternating friction plates and separator plates. A controller typically regulates the fluid pressure by adjusting the magnitude of an electric current to a solenoid which regulates a force on a valve to adjust the pressure. To switch from one ratio to another ratio, one clutch or brake is released and another clutch or brake is engaged. Some shifts require release of multiple clutches and engagement of multiple clutches.
 Making a smooth shift between ratios requires that release of the off-going clutch and engagement of the on-coming clutch be gradual and carefully coordinated. The relationship between the current supplied to the solenoid and the clutch torque capacity is subject to many noise factors. Therefore, accurate control of the clutches requires use of a feedback signal.
SUMMARY OF THE DISCLOSURE
 A vehicle includes a shaft supported within a housing by a bearing with rolling elements, a controller, and a sensor mounted to the housing and configured to transmit a signal to the controller in response to translation of the rolling elements. The rolling elements may be retained within a cage. The sensor may be a proximity sensor such as a Hall effect sensor that produces an electrical voltage that varies depending upon whether the sensor is adjacent to a tooth or a gap on the cage. Alternatively, the sensor may be an acceleration sensor that responds to passage of the rolling elements past a fixed point on the housing. The sensed speed may be used to control the torque capacity of a transmission clutch. When the transmission is not shifting, the sensor reading may indicate a pre-load issue with the bearing.
BRIEF DESCRIPTION OF THE DRAWINGS
 FIG. 1 is a schematic illustration of a vehicle powertrain.
 FIG. 2 is a cross section of a double row ball bearing with a proximity based cage speed sensor.
 FIG. 3 is a cross section of a tapered roller bearing with an acceleration based cage speed sensor.
 FIG. 4 is a cross section of transaxle potential applications of bearing speed sensors such as those illustrated in FIGS. 2 and 3.
 FIG. 5 is a flowchart of a method of controlling a transmission equipped with bearing speed sensors such as the transmission of FIG. 4.
 Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
 FIG. 1 schematically illustrates a front wheel drive vehicle powertrain. The heavy lines indicate the flow of mechanical power, whereas the dashed lines indicate the flow of information. An internal combustion engine 10 generates mechanical power by converting stored chemical energy in a fuel source. Transaxle 12 adapts the speed and torque of the mechanical power produced by the engine to suit the current needs of the vehicle. Mechanical power from transaxle 12 is routed to left and right wheels 14 and 16.
 Within the transaxle, power is transmitted by a torque converter 18, a gearbox 20, and a differential 22. Gearbox 20 provides the main variable ratio gearing. Torque converter 18 facilitates vehicle launch from zero speed by transmitting torque when the vehicle is not moving. Torque converter 18 includes an impeller driven by engine 10 and a turbine connected to an input of gearbox 20 by a turbine shaft 24. Torque converter 18 may also include a lock-up clutch to improve efficiency after vehicle launch. Differential 22 provides roughly equal torque to each wheel while accommodating slight differences in speed such as when the vehicle turns a corner. Power may be transferred from gearbox 20 to differential 22 via gearing 26 that multiplies torque by a fixed final drive ratio. In a rear wheel drive vehicle layout, the differential is typically a separate unit separated from the transmission by a driveshaft. The differential of a rear wheel drive vehicle also changes the axis of rotation by roughly 90 degrees and adjusts the speed and torque by a fixed final drive ratio.
 The transaxle 12 includes a controller 28 which sends electrical signals to a valve body 30. In response to these electrical signals, the valve body 30 controls pressures in fluid passages to clutch apply chambers within gearbox 20 to select and shift among gear ratios. Controller 28 relies on signals from sensors to help determine how much pressure to command. Among these sensors are an input speed sensor 32 configured to measure the speed of turbine shaft 24 and an output speed sensor 34 configured to measure the speed of a shaft in the final drive gearing 26. Additional speed sensors may indicate the speeds of shafts within gearbox 20.
 An upshift is performed in two stages: a torque transfer stage and an inertia phase. During the torque transfer phase, the torque capacity of the off-going clutch is gradually reduced and the torque capacity of the on-coming clutch is gradually increased. The speeds of the transmission elements, in proportion to the speed of the transmission input do not change substantially during the torque phase, although there may be some slip across the off-going clutch. If the on-coming clutch is engaged too slowly relative to the release of the off-going clutch, an engine flare occurs in which the speed ratio increases. If the on-coming clutch is engaged too rapidly, on the other hand, a tie-up condition occurs in which the output torque decreases excessively. To avoid either engine flare or tie-up, the controller may control the off-going clutch to maintain a slight slip speed using feedback control based on a measured transmission speed ratio. Measuring the transmission speed ratio requires measuring the speeds of at least two transmission elements, usually the output shaft and the turbine shaft.
 Once the off-going clutch is completely released, the torque transfer phase ends and the inertia phase begins. At the beginning of the inertia phase, the on-coming clutch is transmitting torque with a substantial slip speed. During the inertia phase, the slip speed gradually decreases as the transmission speed ratio approaches the upshifted gear ratio. The torque capacity of the on-coming clutch is controlled to approach the upshifted gear ratio at the desired rate. If the torque capacity of the on-coming clutch is too low, the shift takes too long. If the torque capacity is too high, there may be an excessive torque variation as the shift finishes. To avoid torque disturbances, it is especially important to control the speed ratio as it approaches the upshift speed ratio at which point the on-coming clutch transitions from slipping to fully engaged. Accurate measurement of the speed ratio is crucial in order to provide a proper feedback signal to the controller.
 Downshifts also have a torque transfer phase and an inertia phase although they occur in the opposite sequence. During the inertia phase of a downshift, the torque capacity of the off-going clutch is reduced and controlled such that the speed ratio increases at the desired rate. Once the speed ratio reaches the downshifted ratio, the on-coming clutch is gradually engaged and the off-going clutch released to change the power flow path.
 Although most shifts only have one off-going clutch and one on-coming clutch, some shifts involve multiple off-going clutches and multiple on-coming clutches. To determine the slip speed of each slipping clutch during such as shift, additional speed sensors are required.
 Typical automatic transmission shaft speed sensors use a stationary sensor, such as a Hall effect sensor, mounted to the transmission housing in close proximity to the shaft. A toothed wheel with particular magnetic properties may be fixed to the shaft. The sensor generates an electric voltage or an electric current that varies depending on whether a tooth of the wheel is currently adjacent to the sensor or a gap between teeth is currently adjacent to the sensor. This oscillating electrical signal is processed to determine the speed of the shaft. For example, the controller may measure the length of time between the passage of a tooth and the passage of the previous tooth or may count the number of teeth that pass within a specific time interval. A speed sensor is only able to accurately determine a speed if teeth pass the sensor frequently. Therefore, there is a minimum detectable speed. Increasing the number of teeth on the toothed wheel reduces the minimum detectable speed. However, an excessive number of teeth may reduce the ability to measure higher speeds. A simple speed sensor only detects the magnitude of the rotational speed, not the direction. However, addition of a second sensor offset from the first produces a second oscillating signal. The controller can determine the direction of rotation based on the phase difference between the signals.
 The gears, shafts, and clutches of an automatic transmission are often packed closely together to reduce the space required. Sometimes, it is difficult to find a location on a shaft to fix a toothed wheel such that the wheel is in close proximity to a sensor. Additionally, the toothed wheel may complicate the assembly sequence or make assembly impossible.
 Shafts within a transmission are typically supported by bearings or bushings. The bearings and bushings react radial forces while reducing friction. Some bearings or bushings support a shaft relative to the stationary housing while others may support a shaft relative to another shaft. A bushing reduces friction by providing a low friction coefficient between the surfaces that have relative motion. A bearing, on the other hand, provides a number of rolling elements that separate the shaft from the supporting component while rolling with respect to both the components. Several types of bearings are common in automotive transmissions. Ball bearings, roller bearings, and tapered roller bearings differ based on the shape of the rolling element. Ball bearings and tapered roller bearings react axial forces as well as radial forces. Bearings also differ based on how the rolling elements are retained. In a caged bearing, the rolling elements are spaced apart from one another by a cage. In a full complement bearing, the rolling elements are retained only by the inner and outer races.
 For a caged bearing, when the bearing has sufficient preload, the cage rotates at a speed which is a weighted average of the speed of the inner race and the outer race. The weighting factors are proportional to the relative diameters of the inner and outer races. Since these diameters are known, if the speed of the cage is measured and the speed of one of the races is known, then the speed of the other race can easily be calculated. When one of the races is fixed to the housing, the rotational speed of that race is always zero. The other race is fixed to the shaft. In some cases, it is possible to fix a toothed wheel to a bearing cage, or form the teeth integrally into the bearing cage, where it would have been difficult or impossible to fix a toothed wheel directly to the rotating element. A Hall effect sensor, or other proximity sensor can be utilized to determine the speed of the bearing cage from which the speed of the shaft can be inferred.
 FIG. 2 shows a double row ball bearing supporting a gear 40 with respect to a fixed housing 42. A bearing inner race 44 is fixed to the housing 42 while a bearing outer race 46 is fixed to the gear 40. Balls 48 and 50 roll within grooves in the inner and outer races. The balls are positioned circumferentially with respect to other balls by cage 52. The cage may be stamped, molded, or machined from metal or from a polymer resin. A number of teeth 54 are formed or cut into one edge of the cage. A proximity sensor 56, such as a Hall effect sensor, transmits an electrical signal to controller 28 such that either the voltage or the current varies depending on whether or not a tooth is adjacent to the sensor. If the cage material is a polymer resin or other non-magnetic material, it may be necessary to apply a metallic coating to the teeth. Alternatively, a non-metallic frame may be fixed to a metallic insert defining the teeth by molding or pressing the insert into the frame. Although the stationary housing is shown inside the rotating element in FIG. 2, in other configurations the inner element may rotate and the outer element may be stationary.
 Proximity sensors are not the only way of sensing speed based on a bearing. As a rolling element passes over a point on a race, the surface of the race deflects slightly. This slight deflection can be detected by placing an acceleration sensor, load (force) sensor, or acoustic emission sensor close to the race surface. The sensor output will show a pulse as each rolling element passes over. When the sensor is in a fixed race, the cage speed can be determined from the frequency of the pulses and the number of rolling elements in the cage. Specifically, the speed of the cage in revolutions per minute is equal to the frequency in cycles per second divided by the number of rolling elements multiplied by 60. The speed of the shaft can be calculated from the cage speed based on the relative diameters of the inner and outer races as described above. An acceleration sensor, load sensor, or acoustic emission sensor may also be used with full complement bearings.
 FIG. 3 shows a tapered roller bearing supporting a shaft 60 with respect to a fixed housing 42. A bearing inner race 62 is fixed to the shaft 60 while a bearing outer race 64 is fixed to the housing 42. Tapered rollers 66 separate and roll with respect to the inner and outer races. The rollers are positioned circumferentially with respect to one another by cage 68. An acceleration sensor 70, transmits an electrical signal to controller 28 with either a voltage spike or a current spike as each roller passes under the sensor. Although FIGS. 2 and 3 show a proximity sensor with a ball bearing and an acceleration sensor with a tapered roller bearing, either type of sensor may be used with either type of bearing.
 FIG. 4 shows a cross section of a front wheel drive transaxle illustrating several locations that a bearing speed sensor may be utilized. The fixed elements include the main housing 80, a converter housing 82, and a front support 84. The converter housing 82 is bolted to the main housing 80. The front support is bolted to the converter housing at 86. A turbine shaft 88 is driven by a torque converter (not shown). A gearbox (not shown) transmits power from turbine shaft 88 to output shaft 90 at various speed ratios. Output gear 92 is fixed to output shaft 90 and supported by front support 84 by means of double row ball bearing 94. Bearing 94 could be configured as a speed sensor using either a cage proximity sensor as illustrated in FIG. 2 or an inner race acceleration sensor. Intermediate shaft 96 is supported at one end by main housing 80 via tapered roller bearing 98 and at the opposite end by converter housing 82 via tapered roller bearing 100. Intermediate shaft 96 is driven by gear 102 meshing with output gear 92. Bearings 98 or 100 could be configured as a speed sensor using either a cage proximity sensor or an outer race acceleration sensor as illustrated in FIG. 3. Since the speed of intermediate shaft 96 is directly proportional to the speed of output shaft 90, output speed could be calculated from these speed sensors. Differential carrier 104 is supported main housing 80 via tapered roller bearing 106 and by converter housing 82 via tapered roller bearing 108. Carrier 104 is driven by gear 110 meshing with gear 112 which is fixed to intermediate shaft 96. Bearings 106 or 108 could be configured as a speed sensor using either a cage proximity sensor or an outer race acceleration sensor. Axle shaft 114 and 116 are driven by differential carrier 104.
 Some types of bearings, particularly tapered roller bearings, require a sufficient axial force, called a pre-load, for proper function. When the pre-load is inadequate, the rolling element may skid with respect to one of the races as opposed to rolling. When this happens, the speed of the cage and the passing frequency of the rolling elements, will not have the predicted relationship to shaft speed. When the transmission is operating in a fixed gear ratio, as opposed to being in the midst of a shift, the ratio of input speed to output speed is known. Therefore, if the measured speed ratio based on a turbine speed sensor and an output speed sensor is not equal to the known speed ratio, and one of the speed sensors is a bearing speed sensor, then improper pre-load on the corresponding bearing should be suspected.
 FIG. 5 is a flow chart for a method of controlling a transmission having bearing based speed sensors. At 120 and 122, the turbine speed and output speed are calculated based on readings from the speed sensors. At 124, these speeds are used to calculate the transmission speed ratio. At 126, the method branches based on whether or not the transmission is currently shifting. During a shift, a clutch is controlled in closed loop to achieve a desired speed ratio profile at 128. For example, the on-coming clutch would be controlled during the inertia phase of an upshift and the off-going clutch would be controlled during the inertia phase of a downshift. If the transmission is not currently shifting, the calculated ratio is compared to the expected transmission ratio for the current gear at 130. If the two are not equal, a flag is raised at 132 to trigger further diagnostic measures or failure management features. For example, the controller may conclude that the unexpected reading is attributable to an inadequate pre-load on the bearing.
 While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. As such, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and can be desirable for particular applications.


Cancels and replaces the first edition (1982). Lays down the methods and test conditions for testing battery-supplied ignition systems for spark-ignited internal combustion engines. Gives two methods of obtaining the results necessary for calculating the system output energy.
Status : PublishedPublication date : 1995-04
Edition : 2Number of pages : 10
Technical Committee:Electrical and electronic components and general system aspects
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Proc. SPIE. 6024, ICO20: Optical Devices and Instruments
KEYWORDS: Signal to noise ratio, Diffraction, Optical transfer functions, Point spread functions, Visualization, Imaging systems, Image processing, Image resolution, Wavefronts, Wigner distribution functions
The aim of this work is to propose a positiveness constraint on the Wigner Distribution Function (WDF) of the detected image of two incoherent point sources: if WDF lacks of zeroes along the frequency coordinate the object can not be resolved by imaging and detected systems; otherwise, it can. This criterion can be applied without preference for a circular clear diffraction limited aperture and for complex apertures with small aberration values; furthermore, it holds if the intensity of each source is different or even when the sources are not points.
In this work we describe a lithographic technique for fabrication of Fresnel lenses. This technique is achieved using a photo mask and Norland Optical Adhesive No. 65. The main characteristics of this lens are his low cost and its flexibility due to the material. Some experimental results are shown.
The aim of this work is to find a resolution value for grating spectrometers when two spectral lines are analyzed. The phase space representation is used to find this value when the following proposal is employed: If the Wigner distribution function is positive along the space frequency axis (at the origin of the space axis) then the two spectral can not be resolved; otherwise, the spectrometer resolve them.
The first method for designing the amplitude hologram was proposed by Lohmann employed properties of irregular amplitude diffraction gratings, that is, every slit of the
diffraction grating is smashed into pieces where every piece has a position (P) and a wide (W),
the control of these parameters enable the detour and the change of a wave front to one that we
want. Though it has a few inconveniences, which are show in this work. One analysis of the
diffraction patterns with various geometric apertures differences to the Lohmann type is showed
too. These coding methods are apply to Fourier and Fresnel holograms type. We shown the
effect of the surround that each one causes in the diffraction pattern in order to determine the
conditions for the better visualization of the reconstructed image.
Crystallization plymerization can be generated in the glucose with fructose when ultraviolet light it is irradiated; the crystallization polymerization opens up possibilities to the material, as matrix to record holographic images, applied conventional microlithography techniques with ultraviolet ligth. The masks with the information is transferred as a modulation of polymerized regions, where were exposed to UV light and regions without plymerization not exposed to UV light. Shows phase modulation by refraction index. Because the polymerized areas presents less density, than the nonexposed areas, changes the emulsion density can be interpreted as changes of refraction index. A developed process is not required, because the material is developed itself; for a physical-chemical mechanism well-known as process cured reaction.
In this work we describe an experimental technique to measure the refraction index of the 3M PP2500 film which has good behavior as quarter wave retarder plate for λ=633 nm. This technique is achieved when two perpendicular linearly polarized beam from a Wollaston prism are incident on the thickness of the film. The beams were incident parallel to the fast axis to measure the ordinary refraction index and parallel to the slow axis to measure the extraordinary refraction index. Some experimental results are shown.
We present a new recorder material, with the possibility to apply to record computer phase holograms, kinoforms, etc. This material is an acrylate monomer with mercapato adhesive, and can be easily to apply for any substrate with out dark room and critical conditions. Due that the absorption spectra from the acrylate monomer adhesive it is localized at UV region (lambda) = 300. We record with lithographic techniques phase grating in this material was made, showing good diffraction efficiency. An important characteristic it is that not necessary the developed process. Our case, the developed processes correspond only the cured polymers process. These properties are attractive due that open the possibility to control the phase material with only to control the cured process. The phase modulation of this material is due by refraction index.
We propose a technique to produce conical beams. This effect is produced when a conventional beam laser through the radial amplitude computer hologram. The computer hologram can be designed to produce a first order ring of light distribution with a spot in the center of the screen, elliptical distribution or another conical distribution are designed and shown. With these computer holograms, we can modulate the spatial structure of the light source. With the radial amplitude hologram is possible to produce different conical distribution, only with incorporate a phase term in the hologram function.
Different techniques for making digital holograms in order to synthesize true 3D images have been reported. The generation of digital Fresnel holograms by means of the ray- tracing method is the most flexible way and relatively simple, that is the objects are considered to be composed of a large number of discrete points sources of light, and the complex amplitude of spherical waves from each point sources is super-imposed on the hologram plane, however there is carry out a great amount of calculate. We presented a technique in order to evaluate simultaneously eight points on the hologram plane, so we obtain a reduction in a factor of eight the computation time. The equation of Kirchhoff- Fresnel is first calculated applying symmetry conditions avoided the redundancy in the calculations and later added the reference wave; also the precision in the values of the complex amplitude is not loss. Other methods that have been reported coupled components doing the ray tracing methods quicker yet.
We show Ronchi grating made of cellophane; this device has the particularity of modulate the polarization state of an arbitrary polarizes source. The grating period can be designed to obtain two linear perpendicular polarization states, horizontal and vertical, or circular, right and left if the source has linear or circular polarization state respectively. With this grating, we can modulate or demodulate images for stereoscopic applications.
Since recent years some activity has developed and characterized the field of research on polymers dispersed liquid crystals (PDLC's). They are useful for a variety of electro-optical applications including windows, displays and other devices. We presented a color filter with PDLC optical activity. This PDLC device was doped with cholesteric liquid crystal. This substance rotates the plane of polarization of a beam of light traversing through them and they are said to be optically active. The mixtures make an uniform behavior pitch in each micro-droplet of the PDLC. The scattering do not destroyed the optical activity of the cholesteric liquid crystal. It is not necessary to observed colors by reflection; we can observe them by across linear polarizers. When the PDLC is on, the colors disappear and when the PDLC is off, colors return.
In this work we proposed an alternative criterion to the Rayleigh and Sparrow to resolve two incoherent point sources when the pupil function of the optical system is a slit. The analytical results and numerical simulation are based on the Wigner distribution function given a minor resolution value than the other two criterions.
In this work we show the behavior of digital hologram obtained with the Kirchhoff-Fresnel's integral when these hologram are written on a TV monitor and this monitor has a finite number of gray levels. The Kirchhoff-Fresnel integral is numerically evaluated and represented in the computer virtual space. When the integral obtained values are showed on the TV screen they are changed due to the number of gray levels. Therefore in the reconstruction step of the hologram obtained on the TV screen we expect some details deterioration in the obtained holographic image.
In this paper we propose a technique to make numerical Fresnel holograms for binary and gray level objects, using Kirchhoff-Fresnel diffraction scalar theory in the paraxial approximation. These holograms produce a real image which can be observed in the reconstruction process with a He-Ne laser.
In this work is presented a multiplexing technique to produce color plane holograms using a single wavelength. A color digital scene is separated in its three basic colors by software. Each monochromatic scene generated with a PC computer is sending to a liquid crystal, which is used as a gray levels discrete transparency, and with a plane reference beam, previously calculated, a hologram is registered in the holographic film plate for each basic color.


Dallas, Tex. Texas Instruments Inc. (TI) said it has introduced the industry's smallest remote junction temperature sensors with a built-in local temperature sensor. Housed in a 8-lead SOT23 package, the single remote channel TMP421 and dual remote channel TMP422 deliver remote sensor accuracy of ±1°C (maximum) and a local temperature sensor range of ±1.5°C (maximum).
The TMP421 and TMP422 sensors operate on a standard I2C/SMBus compatible, two-wire interface over a temperature range of -40°C to 125°C, with a remote temperature range of up to 150°C. For maximum power savings, the device circuitry (other than the serial interface) can be shut down, reducing current consumption to typically less than 3 uA.
The sensors also feature multiple addresses. The remote temperature sensor diode-connected transistors are typically low-cost NPN- or PNP-type transistors or diodes that are an integral part of microprocessors, microcontrollers and FPGAs. The TMP421 and TMP422 also include series resistance cancellation, programmable non-ideality factor and diode fault detection.
Both sensors are RoHS compliant and can be used in many applications including LCD/DLP/LCOS projectors, servers, central office telecom equipment and laptop computers. They are also suitable for industrial controllers, processor/FPGA temperature monitoring and storage area networks.
Pricing: The TMP421 is priced at $1.25 each and the TMP422 is priced at $1.65 each, both in quantities of 1,000 (suggested resale pricing).
Availability: The TMP421 and TMP422 are available now from TI and its authorized distributors.
Product information: TMP421, TMP422 and analog design support and selection guide
Texas Instruments , 1-800-477-8924, www.ti.com


Discovery stage studies that address issues of absorption, distribution, metabolism and excretion (ADME) are vital for lead optimization resulting in new drug candidates. Often pharmacokinetics (PK) is assessed in these experiments without regard for the metabolism of the compound or the potential for metabolites to circulate in vivo. This work presents a strategy for drug level determination and detection of metabolites using dried blood spots for sample collection. Initially, metabolites are detected from microsomal incubations and characterized using tandem mass spectrometry. Data dependent enhanced MS and enhanced product ion (EMS-EPI) scanning with dynamic background subtraction was used on a hybrid quadruple linear ion trap mass spectrometer. On-the-fly background subtraction greatly improved the detection of metabolites. These data were used to build a multiple reaction monitoring (MRM) method for the parent and metabolites. MRM-EPI scanning was used to analyze the extracted dried blood spots from the PK study. Circulating metabolites were detected using MRM and their identities confirmed on the basis of fragment ion spectra collected simultaneously. The use of dried blood spots provides a means for re-analysis of PK samples for metabolite identification without the need for complex sample storage and preparation. Both parent compound and metabolite information can be collected in these studies, resulting in a savings of time and resources.
Copyright (c) 2005 John Wiley & Sons, Ltd.