US 6239598 B1
A k-space trajectory measurement method is disclosed with applications in magnetic resonance spectroscopy. Phase shift values associated with magnetic resonance signals from multiple sample regions are compared to rapidly extract k-space trajectory measurements. The efficiency of the present invention for image gradients to be measured immediately before test imaging.
1. A method for trajectory measurement in magnetic resonance spectroscopy comprising the steps of:
acquiring signals from a plurality of excited regions, each region having a spin density function and an accumulated phase shift;
determining an excited region gradient amplitude;
locating a first excited region relative to a second excited region;
determining a k-space trajectory of the first excited region data at a predetermined time relative to the second excited region data;
determining a difference in the accumulated phase shift between the first excited region and the second excited region; and
extracting the k-space trajectory from the excited region data.
2. The method of claim 1 wherein the first and second regions are spatially adjacent.
3. The method of claim 1 further comprising determining k-space trajectory errors associated with a field inhomogeneity.
4. The method of claim 3 wherein determining k-space trajectory errors is accomplished by measuring a phase perturbation in the presence of a zero region gradient.
5. The method of claim 3 wherein determining k-space trajectory errors is accomplished by measuring field inhomogeneity differences between the excited regions.
6. The method of claim 1 wherein said plurality of regions are slices normal to an axis.
7. The method of claim 6 wherein the axis is x-axis and the first excited slice data at x=x0 satisfies
where ρ(x0,y,z) is a spin density function over the first excited slice at x0, Φ(t) is an accumulated phase shaft, and kx(t) is a k-space trajectory.
8. The method of claim 6 wherein the difference in the accumulated phase shift between the first and second excited slices ∠S2(t)−∠S1(t) as a function of time satisfies
where kx(t) is k-space trajectory, x1 is a position corresponding to the first excited slice and x2 is a position corresponding to the second excited slice.
9. The method of claim 1 wherein said plurality of regions are pencils normal to an axis and a second orthogonal axis.
10. A magnetic resonance image processed according to the method of claim 1.
11. The magnetic resonance image of claim 10 wherein the image is a spiral scanning image.
12. The magnetic resonance image of claim 10 wherein the image is an echoplanar image.
13. A method for trajectory measurement in magnetic resonance spectroscopy comprising the steps of:
acquiring signal from a plurality of adjacent excited slices normal to an axis, each slice having a spin density function and an accumulated phase shift wherein the excited slice normal to the x-axis at arbitrary position x=x0 satisfies
where ρ(x0,y,z) is a spin density function over the first excited slice at x0, Φ(t) is an accumulated phase shaft, and kx(t) is a k-space trajectory;
determining a slice gradient amplitude;
locating the x=x0 excited slice relative to a second excited slice;
determining a k-space trajectory of the x=x0 excited slice at a predetermined time relative to the second excited slice;
determining a difference in the accumulated phase shift between the x=x0 excited slice and the second excited slice ∠S2(t)−∠S1(t) as a function of time according to
where ρ(x0,y,z) is a spin density function over the x=x0 excited slice at x0, Φ(t) is an accumulated phase shaft, and kx(t) is a k-space trajectory; and
extracting the k-space trajectory from the excited slice data.
This patent application claims priority of provisional patent application 60/084,687, filed May 8, 1998, entitled “Process for Rapid Sample Trajectory Calibration for Magnetic Resonance Imaging.”
1. Field of the Invention
The present invention relates to a process for producing magnetic resonance images using actual sample trajectories to produce images without errors caused by sampling errors in the spatial frequency space (the k-space). The invention permits the measuring of magnetic resonance imaging sample trajectories in situ from the imaged subject or patient directly and efficiently. The process measures the k-space trajectory using phase values of acquired magnetic resonance signals.
2. Description of the Prior Art
The process of producing images based on readings from magnetic resonance equipment and a number of k-space calibration approaches have been described in both patents and printed literature (1-5). One prior method calibrates the test gradient waveforms using self-encoding gradients. This prior method measures k-space trajectory by analyzing the temporal locations of echo peaks produced by the combination of self-encoding gradients and a test gradient waveform.
Another prior approach measures the actual k-space trajectories by recording signals from a small phantom at a number of locations inside the imaging field (5-8). The time varying magnetic field at the probe location is recorded via phase differences of the acquired data and k-space trajectories are then obtained by solving a set of linear equations.
Still another prior art technique for measuring the actual sample trajectories involves measuring the driving currents of gradient amplifiers (9, 10). Other techniques currently being researched include an approach which establishes landmarks in the k-space by applying short radio frequency pulses at selected times during the k-space traversal (11). Actual k-space trajectories are then determined from the established landmarks.
There have also been many patents in the field of magnetic resonance imaging utilizing information derived from k-space. U.S. Pat. No. 5,621,321 entitled “Magnetic Resonance Scan Calibration Method for Ultra Fast Image Acquisition” describes a method in which data lines are one-dimensionally transformed into a frequency encoded direction. Other techniques have been used for producing images from magnetic resonance techniques such as the technique using gradient echoes and spin echoes or (Grase). This technique, however, selectively phase encodes and time shifts the echo responses and occurrence so as to smoothly distribute unwanted phase shift from field inhomogeneity and/or chemical phase shift effects over the phase encoded dimension in k-space. U.S. Pat. Nos. 5,680,045 and 5,270,654 utilized this Grase technique.
Each of the prior mentioned approaches has its shortcomings. The self-encoding approach takes a long time, and its accuracy is dependent on the accuracy of realized self-encoding gradient amplitude. Gradient performance non-linearity is not accounted for. The RF landmark method is also time consuming and because of the limits in the temporal resolution of the RF impulses and limits on the RF energy deposition, only a few k-space locations are marked during each acquisition. Large numbers of repetitions are necessary to measure an entire k-space trajectory. The small phantom method requires separate phantom experiments and the gradient current monitoring does not account for eddy currents.
Magnetic resonance images are reconstructed from discrete samples of the imaged object's distribution in the spatial frequency domain (the k-space). Actual sampling trajectory in the k-space often deviates from that specified by the ideal spatial encoding gradient waveforms due to imperfections in gradient amplifier performance, readout timing errors, and eddy currents induced by gradient pulses. The resulting misregistrations in k-space sample locations cause image artifacts and distortions in images reconstructed using ideal k-space sample locations. Echo planar imaging, fast spiral scan MRI, and other fast non-Cartesian scan MRI techniques that are widely used in many important imaging applications such as functional brain imaging, interventional imaging, etc., are especially susceptible to this type of image errors.
Modern magnetic resonance scanners use actively shielded gradients and electronic compensation measures to reduce and compensate for induced eddy currents. Despite these corrections, substantial k-space sample trajectory deviations still exist, especially for fast imaging applications that require fast gradient switching and/or ramping (e.g., echo planar imaging) or, use complicated non-Cartesian sampling patterns (e.g., spiral scanning magnetic resonance imaging). In the former case, gradient amplifiers may be driven into a nonlinear operating range causing gradient waveform distortions and thereby k-space sample trajectory deviations. In the latter case, the use of complicated non-Cartesian scan patterns makes eddy current compensation by common measures, mostly adjusted for proper compensation of trapezoidal waveforms, less effective. In most of these cases, due to higher than normal sampling rates, image errors caused by readout timing errors are amplified.
Effects of k-space sample location misregistration can be corrected by reconstructing images using the actual k-space trajectories by regridding interpolation and Fast Fourier Transforms (FFT) (12). Because of aforementioned shortcomings of prior art methods for the measurement of actual k-space trajectories, such measurements are only made for a limited number of scan orientations and field of views. Imaging in other orientations or with other field of views suffers from significant errors due to k-space trajectory deviations. Thus, there exists a need for a technique that can measure k-space trajectories in situ to allow imaging in arbitrary orientations that best fit the requirements of each particular study.
The present invention provides a novel technique for the measurement of k-space trajectory. This technique determines the actual k-space trajectory from phase values of acquired magnetic resonance signals collected for a plurality of excited slices. The correct k-space locus at each readout point is calculated from corresponding phase difference between acquired magnetic resonance signals of adjacent slices.
The measurements of k-space trajectories are made from the imaged subject/object directly and occurs in a few seconds or less using a few readout lines. The invention provides an accurate set of data for correcting image errors caused by non-ideal sample trajectories in magnetic resonance imaging (MRI) exams that employ scan techniques sensitive to sample trajectory deviations, illustratively including echo planar imaging and fast spiral scan techniques, thereby increasing the sensitivity and specificity of the MRI exams. The present invention also improves response of spatially and spectrally selective excitations in MRI.
The method of the present invention is suitable for trajectory measurement in magnetic resonance spectroscopy and includes acquiring signal from a plurality of excited regions, each region having a spin density function and a cumulative phase shift associated therewith. Thereafter, an excited region gradient amplitude is determined and a second excited region is scanned at a known separation from a first excited region. A k-space trajectory for the first excited region at a predetermined time relative to the second excited region is determined in addition to a difference in the accumulated phase shift between the regions. A k-space trajectory is then extracted therefrom. The present invention is useful in calculating magnetic resonance images.
FIG. 1 is a pulse protocol operative in the present invention to measure an interleaf of a test spiral gradient waveform.
FIG. 2 is a graph showing the kx trajectory of a spiral interleaf measured from the pulse protocol of FIG. 1 using a spherical gel phantom and using a human subject. In comparison, the same trajectory as measured by the “small phantom” method is also plotted in FIG. 2. The ideal trajectory of this interleaf is shown in FIG. 2 as the shaded curve.
FIG. 3 is a graph showing the maximum difference between the kx trajectories measured by the present invention using the gel phantom and using the human subject, displayed at an amplitude scale 25 times that of FIG. 2.
FIG. 4 is a graph showing the ky trajectory of the spiral interleaf measured from the pulse protocol of FIG. 1 using a spherical gel phantom and using a human subject. The same trajectory as measured by the “small phantom” method is also plotted in FIG. 4. The ideal trajectory of this interleaf is shown in FIG. 4 as the shaded curve.
FIG. 5 is a graph showing the maximum difference between the ky trajectories measured by the present invention using the gel phantom and using the human subject, displayed at an amplitude scale 25 times that of FIG. 4.
FIG. 6 shows images of a small phantom reconstructed using k-space trajectories (a) measured by the present invention, (b) measured by the “small phantom” method, and (c) the ideal trajectory.
FIG. 7 shows spiral images (64×64) of a spherical gel phantom reconstructed using k-space trajectories (a) measured according to the present invention, (b) measured by the “small phantom” method, and (c) the ideal trajectory.
FIG. 8 shows spiral images (64×64) of a human head reconstructed using k-space trajectories (a) measured according to the present invention, (b) measured by the “small phantom” method, and (c) the ideal trajectory.
The present invention includes a novel k-space trajectory measurement method suitable for studies of homogeneous and inhomogeneous subjects. The present invention is notably faster than prior art methods requiring only a few readout lines to determine k-space trajectories. Post-acquisition data manipulation is largely obviated by the present invention because scan times for measuring each gradient channel require only a few seconds and k-space trajectories are measured directly at the readout points. Further, k-space trajectories are directly measured by scanning the test subject, allowing image gradients to be measured immediately before an actual imaging session. Immediately preceding measure of image gradients before an actual test imaging session allows for selection of arbitrary and uncalibrated scan orientation, field of view and similar operational parameters.
While the present invention is detailed herein in reference to slices normal to an arbitrary axis, it is appreciated that other shape and dimensionality signal sampling regions are readily devised.
In the process of the present invention, signals from an excited slice normal to the x axis at x=x0 are acquired. In order to acquire this signal, the spatially varying B0 field inhomogeneity and relaxation effects are neglected and an infinitely thin slice thickness is assumed. The formula for the slice is:
In the preceding formula ρ(x0,y,z,) is the spin density function over the excited slice at x0, φ(t) is the accumulated phase shift induced by temporal B0 field shifts and kx(t) is the k-space trajectory being measured. The kx trajectory is explicitly encoded in the phase of the acquired data.
In order to extract the kx(t) from the phase values of the acquired signal shown in Equation (1), two closely placed slices at x=x1 and x=x2 are acquired and kx(t) is then determined by the phase differences of acquired signals from the excited slices.
The slice located at x1 and x2 in Equation 2:
is determined by combination of the slice selective gradient amplitude and modulation frequency of the slice selective radio frequency excitation pulse. The errors and their determinations cause the calculated kx(t) to be scaled.
The precise radio frequency modulation is achieved with radio frequency electronics which are well known in the art. This allows the slice locations to be determined in an accurate and precise way. The deviations in slice profile have a limited effect on the calculated kx(t) since both ∠S1(t) and ∠S2(t) are affected similarly by slice profile deviations.
In the preferred embodiment, the imaged object is relatively uniform in the measured gradient direction over the small distance of the selected slice gap. The gradient field and the B0 shift are explicitly modeled in relation to the phase evolution of the acquired data in Equation 2. Spatially varying B0 field inhomogeneity is not addressed in the equation since the overall phase difference produced by it is insignificant in comparison to the normal phase difference equal to the product of the slice gap and the test gradient amplitude. In instances where severe field inhomogeneity exists in the imaged object, additional data may be needed to explicitly measure its contribution to the overall phase changes. In the preferred embodiment the data sampling is along a single axis (i.e. kx, ky or kz) and acquired signals are of high signal to noise ration to ensure the accuracy of the k-space trajectory determination.
Once the kx(t) has been determined, the accumulated phase shift induced by temporal B0 field shifts can be solved iteratively, with φx(0)=0,
ky(t) and φy(t) can be measured similarly with slices excited normal to the Y axis. The overall phase accumulation due to B0 shift is:
The accuracy of the measured k-space trajectories is determined by subjecting different test objects to the same magnetic gradients. A six-interleaved spiral cage trajectory is measured by the present invention using the pulse protocol of FIG. 1. Test subjects included a human head sized round flask containing an ion doped gel and a normal human subject, as described in Examples 2 and 3, respectively. The accuracy of the measured k-space trajectories according to the present invention is assessed by measuring the same spiral k-space trajectories according to the “small phantom” technique (6). The pulse sequence of FIG. 1 used herein acquires the single slice data successively. Data from adjacent slices are acquired successively within a TR period, with adjacent slice spacing selected by adjusting RF modulation frequency. The relative effect of spatially varying B0 field inhomogeneity on k-space trajectory measurement accuracy is assessed by repeating the pulse protocol without applying test gradient waveforms.
The k-space trajectories measured by the “small phantom” method (6), and by the present invention using a gel phantom and a human head are shown in FIG. 2. These kx trajectories are obtained through application of the pulse protocol of FIG. 1. The ideal trajectory is plotted as a shaded curve in FIG. 2. The measured trajectories overlap to the extent that they appear as a single curve in FIG. 2. The maximal difference among the kx trajectories measured by the “small phantom” method, by the present invention using the gel phantom and a human subject is shown in FIG. 3 with a graph amplitude magnified twenty-five times with respect to that of FIG. 2. Similar results for measurement of ky are shown in FIGS. 4 and 5, respectively. Phase variations associated with spatially varying B0 field inhomogeneity is inconsequential compared to that produced by test gradients.
Image reconstructions using measured and ideal spiral k-space trajectories are instructive in assessing sample location misregistrations. Images of a small phantom, reconstructed using k-space trajectories measured by the present invention, by the “small phantom” method and using the ideal trajectories are shown in FIG. 6. A comparison of the point spread like functions in FIGS. 6a and 6 b demonstrates that reconstructed images are improved after k-space sample location misregistrations have been taken into account. In contrast, FIG. 6c shows that a large amount of energy is spread over regions away from the reconstructing point. Further, the central peak's full width at half maximum in FIG. 6 is comparatively broad, indicating strong local smearing in the resulting reconstructed images.
Spiral images of a gel phantom reconstructed using k-space trajectories measured by the present invention from the phantom, measured by the “small phantom” method (6), and the ideal trajectories are shown in FIG. 7. Similarly, FIG. 8 shows human head images reconstructed using k-space trajectories measured by the present invention, measured by the “small phantom” method (6), and the ideal trajectories. The spiral images of the ideal trajectory shown in FIGS. 7c and 8 c show the effects of k-space sample location misregistration. The spiral image quality obtained from the present invention, as shown in FIGS. 7a and 8 a, is considerably improved as compared to that from the small phantom method as shown in FIGS. 7b and 8 b, respectively. The present invention shows considerable improvements in regard to edge definition, as compared to the small phantom method.
While spatially varying B0 field inhomogeneity in the excited slices is largely inconsequential when measuring a well shimmed subject, it is appreciated that a subject with large spatially varying field inhomogeneity and/or spatially varying eddy currents, separate measurement of phase perturbations in the presence of a zero or negligible applied test gradient is optionally conducted.
It is appreciated that in those applications where cross plane dephasing is of concern, the present invention is readily modified to use excited pencils, instead of slices, in order to measure kx and ky simultaneously. Conventional pulse protocols are capable of producing two-dimensional sampling pencils.
In general, the k-space trajectory measurement technique of the present invention enables practical k-space calibration for any imaging applications that are affected by misregistration of k-space sample locations caused by either eddy currents, gradient amplifier performance imperfections, or readout timing errors.
The following examples are set forth to illustrate various embodiments of the present invention. These examples are not intended to limit the scope of the present invention as set forth in the appended claims.
A six interleaf k trajectory is measured using a quadrature volume head RF coil. Each spiral interleaf contains 925 readout points. Readout duration is 11.25 milliseconds. Measurements are performed on a Philips/UAB 4.1-T whole body scanner equipped with a Magnex (Abingdon, England) self-shielded whole body gradient set. Maximum gradient strength is 2.5 gauss per centimeter and the maximum gradient slow rate is greater than 2,500 gauss per centimeter per second. Gradient pre-emphases are determined separately using an RF pulse applied at successive delays after a trapezoidal gradient pulse as shown in FIG. 1. The sequence is repeated four times successively in a single TR period to acquire data from four adjacent slices with a different slice being selected by changing the RF modulation frequency. Gradient pre-emphases time constants are adjusted recursively to minimize eddy current effects observed in the acquired free induction decay signals.
A 2 liter round flask is filled with 2% agar gel containing 4 millimolar copper sulfate and allowed to congeal. Scan time of relaxation (TR) is 500 milliseconds. Time of excitation (TE) is 10 milliseconds. Excitation angle is 60 degrees. Field of view (FOV) is 22 centimeters. Ten dummy scans are conducted as part of the scan parameters. The kx trajectory is measured at four slices in the x direction at locations of −6 millimeters, −3 millimeters, 0 millimeters and 3 millimeters with an excited slice thickness of 3 millimeters. The scan time for the entire experiment is 8 seconds.
The procedure of Example 2 is repeated, substituting the head of a human volunteer for that of the round flask.
64×64 spiral gradient-echo images are obtained from the gel phantom using k-space trajectory measurements as per Example 2. Acquired data is first phase corrected using the measured phase acquisition due to B0 shift. Images are reconstructed by regridded interpolation and fast Fourier transform (13). Images are obtained using the same 4.1 -T scanner of Example 2, using the quadrature volume RF coil. Image scan parameters are as follows: TE=10 milliseconds, TR=500 milliseconds, number of experiments (NEX)=1, FOV=22 centimeters, and slice thickness=5 millimeters.
64×64 spiral gradient-echo images are obtained from a human head subject using k-space trajectory measurements as per Example 3. Images are collected according to the parameters of Example 4 with the exception that TR=2,500 milliseconds and in the human study, inversion pulses are applied 700 milliseconds before the gradient echo imaging sequence to enhance the contrast between gray and white matter.
The present invention having been described in its preferred embodiments, it is appreciated that those skilled in the art are capable of recognizing numerous modifications and embodiments of the present invention without departing from the scope of this invention. Accordingly, the scope of the present invention is defined as set forth by the following claims. All references cited herein are intended to be incorporated to the same extent as if each reference was explicitly incorporated by reference.
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Scale‐up issues for commercial depth filters in bioprocessing
Significant increases in cell density and product titer have led to renewed interest in the application of depth filtration for initial clarification of cell culture fluid in antibody production. The performance of these depth filters will depend on the local pressure and velocity distribution within the filter capsule, but these are very difficult to probe experimentally, leading to challenges in both process design and scale-up. We have used a combination of carefully designed experimental studies and computational fluid dynamics (CFD) to examine these issues in both lab-scale (SupracapTM 50) and pilot-scale (StaxTM) depth filter modules, both employing dual-layer lenticular PDH4 media containing diatomaceous earth. The SupracapTM 50 showed a more rapid increase in transmembrane pressure and a more rapid DNA breakthrough during filtration of a Chinese Hamster Ovary cell culture fluid. These results were explained using CFD calculations which showed very different flow distributions within the modules. CFD predictions were further validated using measurements of the residence time distribution and dye binding in both the lab-scale and pilot-plant modules. These results provide important insights into the factors controlling the performance and scale-up of these commercially important depth filters as well as a framework that can be broadly applied to develop more effective depth filters and depth filtration processes.
|Work Title||Scale‐up issues for commercial depth filters in bioprocessing|
|License||CC BY-NC-ND 4.0 (Attribution-NonCommercial-NoDerivatives)|
|Publication Date||January 14, 2022|
|Publisher Identifier (DOI)||
|Deposited||July 21, 2022|
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We describe a system for wide view imaging, which uses multiple image sensors and mirrors. In this system, each image obtained by the multiple sensors has a non-overlapped area and is equivalent to the partial image of the wide view obtained by an imaginary sensor. Therefore depth estimation from the sensor to each object is not required for combination. In this paper, we describe the wide view imaging system using random access image sensors we have designed and a FPGA (field programmable gate array). We can control the system to show a panoramic image or partial image in real time. The new image sensor has 128×128 pixels, the main functions being random access and interpolation of pixel values on a quarter pitch. We show results obtained by the chip.


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Climatic chambers are used to test equipment under different temperatures and relative humidities (RH).
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- No more waiting for a full charge—can be operated during charging or used up to 12 hours between charges.
- Charging kit includes both universal AC power adaptor and USB charging cable so you can charge anywhere, anytime.
- Pinpoint very small gas leaks quickly and accurately before they cause damage and downtime.
- Compact, handheld unit is easy to operate and convenient to use anywhere you need to check for leaks.
Using metal columns to analyze glycerides in biodiesel offer significant performance advantages compared to fused silica columns, as shown in this evaluation.
High Temp. Stability Problem Solved with New Metal Columns - Analysis of Total Glycerides in Biodiesel Oils by ASTM D-6584 Using New MXT-Biodiesel TG Capillary Columns
The high temperatures required for biodiesel analysis by gas chromatography present a considerable challenge to analytical columns. Fused silica columns, even those rated for high-temperature tolerance, breakdown relatively quickly. Restek’s new MXT-Biodiesel columns are more stable up to 430°C and offer excellent chromatography for glycerides. These columns are available in two configurations: factory-coupled to a 0.53mm retention gap, or with a built-in, leak-proof Integra-Gap retention gap.
We challenged our Rtx-Biodiesel column with analysis for glycerin in biodiesel according to method ASTM D-6584-00. Excellent linearity was established for glycerin, triolein, monolein, and diolein, with r2 values exceeding the method criteria for all compounds. Mono-, di-, and triglycerides resolved well from other compounds in B100 biodiesel oil. Column performance was strong at high temperatures, with low bleed even at 380°C. An Alumaseal connector and guard column were used to extend column life.
This flyer includes data demonstrating the performance of recommended GC columns for the analysis of total glycerin, fatty acid methyl esters (FAMEs), and residual methanol in biodiesel. Features a comparison of metal and fused silica columns. (PDF - 0MB)


Reliability and development
Why choose us?
For nine years, Mplex Technology Sdn Bhd has been established in keeping business in the field of Industrial Engineering, We use the most recent innovations in technology. We supply high quality industrial products like liquid pumps, metering pumps, vacuum compressor pumps, as well as sensor instruments and valves. We specialize in Engineering works, process automation system design, as well as maintenance services.more


AVR - Aeberle Voltage Regulator
All measurement, control and regulation tasks of tap-changing transformers can be executed using the new REG-DA voltage regulator.
The REG-DA regulator features a world innovation as it is equipped with a high-capacity transformer monitoring function in accordance with CEI IEC 354 (VDE 0536). This function allows the operator to call up information about the hot-spot temperature and the lifetime consumption of the transformer at any time. If required, the regulator can even activate up to six cooling levels. The oil temperature can either be recorded directly (PT 100) or via a mA input.
Apart from its basic function, every REG-DA voltage regulator can be used as a measurement transducer, recorder, statistical unit, paragramer and transformer monitor all at the same time. All important network measurement quantities are displayed in measurement transducer mode. The trends in the voltage that is to be regulated over time and a second, selectable, measurement quantity are shown in recorder mode. The statistical unit for the tap-change position offers a clear presentation of all switching operations of the tap changer. The paragramer provides a complete busbar simulation.
Interconnection of multiple voltage regulators on a network enables the mutual exchange of data between regulators over long distances.Various communications methods can be used to transfer data.This allows monitoring of multiple transformers from a centralised control centre. Parallel connection of several transfomers can be very easily implemented this way. Application-specific tasks can be implemented via freely programmable inputs and outputs. The REG-DA regulator is able to communicate with a control centre via all common scada protocols.
|Characteristics of the REG-DA voltage regulator
• large backlit LCD (128 x 128) with all important information (tap-changer position,
• Measuring functions (U, I, P, Q, S, cos ϕ, ϕ, I sin ϕ, f )
• Recorder functions (2-channel chart recorder)
• Statistics functions (records total number of switching operations, switching
operations per tap)
• Event recorder (log book)
• Transformer monitoring functions incl. recording of the hot-spot temperature and
• 14 (26) freely programmable binary inputs• 9 (21) freely programmable binary
• Freely programmable analogue inputs or outputs (mA)
• Pt 100 direct input for RTD temp. probe (option)• Input for tap-potentiometer (200Ω...20kΩ total resistance, option)
• Control of three-winding transformers
• Control of phase-shifting transformers
• Limit value monitoring for all measurement quantities
• 4 freely programmable set-point values
• Programmable rated values of U and I
• Parametric software WinREG for setup, programming and display
as well as for PC-based archiving and evaluation of the recorder data
• Simulation software REGSimTM for the simulation of any parallel operation, network
and load situations
• Implementation of freely programmable control tasks through
• Peripheral bus RS 485 (COM3) for additional interface modules (ANA-D, BIN-D)
• ParaGramer function for the display and automation of any parallel connections
with up to ten transformers


Various parameters of recording spatially modulated coherent light have been studied, with particular emphasis on the parameters related to constructing holograms. These include the ratio of the reference beam’s intensity to that of the signal beam, the offset angle, the film’s transfer characteristic, and the recording wavelength. Experimental results were obtained by recording interference patterns on highresolution film using the 6328-Å line of the He–Ne laser. The bias level of the interference pattern was varied so as to vary the operating point on the curve representing the film’s amplitude transmittance vs exposure characteristics. The percent modulation and the spatial frequency were also varied at each of the operating points. Interference patterns were recorded, using the 4880-Å and 5145-Å lines from the argon laser. From these data, the optimum bias level and the ratio of the signal beam to the reference beam for recording interference patterns are determined. The modulation transfer function of the film can also be determined.
© 1967 Optical Society of AmericaFull Article | PDF Article
OSA Recommended Articles
John C. Urbach and Reinhard W. Meier
Appl. Opt. 8(11) 2269-2281 (1969)
Carlton E. Thomas
Appl. Opt. 11(8) 1756-1765 (1972)
J. Opt. Soc. Am. 56(4) 428-432 (1966)


- Full text PDF available (4)
Ice residual (IR) and total aerosol properties were measured in mixed-phase clouds (MPCs) at the high-alpine Jungfraujoch research station. Black carbon (BC) content and coating thickness of BC-containing particles were determined using single-particle soot photometers. The ice activated fraction (IAF), derived from a comparison of IR and total aerosol… (More)
Below the melting temperature Tm, crystals are the stable phase of typical elemental or molecular systems. However, cooling down a liquid below Tm, crystallization is anything but inevitable. The liquid can be supercooled, eventually forming a glass below the glass transition temperature Tg. Despite their long lifetimes and the presence of strong barriers… (More)
• Whatever the metrics, we are part of the " top-5 " in Brazil.
An innovative time-of-flight distributed telemeter is presented, developed for the installation on train monitoring portals. It is composed of a single transmitter-receiver unit, and of up to six scanning stations, connected to the main unit by fiber optics pairs. The systems operates at 400 kHz, with a measuring range of 0.5-15m, and an uncertainty of ±… (More)


This article presents new optical pixel sensors that are based on hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) for detecting secondary color optical signals to increase the number of colors of sensed light. Three types of series-connected structure with different photo TFTs enable the sensors to receive secondary color optical input signals that combine any two primary colors, such as magenta (blue and red), cyan (green and blue), and yellow (red and green). The secondary color optical sensors also prevent from being affected by light of a single color to integrate with primary color optical sensors for realizing a six-color sensing mechanism. Moreover, only one photo TFT is used to suppress the effect of ambient white light by compensating photocurrents without increasing the complexity of the proposed sensor structure. The measurements demonstrate that the difference in the output voltages is 15.6 V even under ambient white light with an intensity of 10000 lux, proving that the proposed sensor can yield significantly different sensing results with and without an optical input signal under intense ambient white light. Thus, the proposed sensors increase the number of sensed color light that can be integrated with a large TFT-LCD panel for multiuser interaction.
All Science Journal Classification (ASJC) codes


Synchronization Trigger Control System for Flow Visualization 870450
The use of cinematography or holographic interferometry for dynamic flow visualization in an internal combustion engine requires a control device that globally synchronizes camera and light source timing at a predefined shaft encoder angle. The device is capable of 0.35° resolution for rotational speeds of up to 73 240 rpm. This was achieved by implementing the shaft encoder signal addressed look up table (LUT) and appropriate latches. The developed digital signal processing technique achieves 25 nsec of high speed triggering angle detection by using direct parallel bit comparison of the shaft encoder digital code with a simulated angle reference code, instead of using angle value comparison which involves more complicated computation steps. In order to establish synchronization to an AC reference signal whose magnitude is variant with the rotating speed, a dynamic peak follow-up synchronization technique has been devised. This method scrutinizes the reference signal and provides the right timing within 40 nsec. Two application examples are described.


The aim of this study is to present a novel inverse heat transfer method, which incorporates an automatic-filter scheme with the conjugate gradient method, for identifying shapes and temperature of heating elements embedded in a rectangular package. In this report, shapes of the heating elements are visualized by using node-matrix images. A group of unknown heating elements with different shapes, positions, and temperatures are nondestructively identified simply based on the data of the upper surface temperature of the rectangular package. Effects of temperature measurement uncertainty, grid size, and number of measurement points on the top surface on the identification accuracy are evaluated. Results show that the geometric and thermal conditions of the heating elements embedded can be predicted precisely by using the present approach. The approach is found to be stable and insensitive to the temperature measurement uncertainty, and without overwhelming mathematical manipulation, the form of objective function becomes flexible.


This kit includes an aneroid sphygmomanometer matched with the Sprague-Rappaport stethoscope. With its unique five-in-one design, the Sprague-Rappaport stethoscope enables use with adult, pediatric and infant patients. This kit also features a latex free nylon cuff, index and range markings, artery indicator mark, owner ID label, gauge holder, standard inflation bulb and air release valve. This kit also includes a 6"x 9" color-matched nylon case to carry your items. Cuff range: 10"-16". The Prestige A2 kit offers a lifetime calibration warranty. Approximate length is 30".


From Wikipedia, the free encyclopedia - View original article
|This article may require cleanup to meet Wikipedia's quality standards. (June 2009)|
An automotive night vision system is a system to increase a vehicle driver's perception and seeing distance in darkness or poor weather beyond the reach of the vehicle's headlights. They are currently offered as optional equipment on certain premium vehicles.
Active systems use an infrared light source built into the car to illuminate the road ahead with light that is invisible to humans. There are two kinds of active systems: gated and non-gated. The gated system uses a pulsed light source and a synchronized camera that enable long ranges (250m) and high performance in rain and snow.
In late-2005, Mercedes-Benz introduced their Night View Assist system on the redesigned S-class. It was the first system to use the instrument cluster's LCD as a display. In 2009, Mercedes added a pedestrian detection function calling the revised system Night View Assist Plus and offered it on the redesigned E-class and refreshed S-class, however, the E-class uses the navigation screen's display. For model year 2014, S-class with Night Vision Assist Plus will also have animal detection. To give further warning, the Night View Assist PLUS system is coupled to the car’s spotlight function which is able to focus a beam of light onto the pedestrian or animal while flashing them repeatedly. Night Vision Assist is no longer available for the new E-class.
In 2002, Toyota introduced the first production automotive active night vision system or Night View on the Lexus LX 470 and Landcruiser Cygnus. This system uses the headlight projectors emitting near infrared light aimed like the car's highbeam headlights and a CCD camera then captures that reflected radiation, this signal is then processed by computer which produces a black-and-white image which is projected on the lower section of the windshield. In 2008 Toyota added a feature to the Crown Hybrid which highlights pedestrians and presents them in a box on an LCD display in front of the driver, this was the first pedestrian detection feature for an active system.
The Night Vision Assistant was introduced in 2010 on the Audi A8. It uses a thermal imaging camera behind the four rings at the front of the car which can "see" 300 meters (984 ft) ahead. The display in the instrument cluster highlights humans with yellow markings. More importantly, the computer can determine if the person on the road moves in a way that could lead to a collision with the car. In that case the pedestrian is being marked in red color and the driver of the car receives an audible warning.
In fall 2005, BMW introduced BMW Night Vision on the 7-series. This system processes far infrared radiation, which minimizes non-essential information placing a greater emphasis on pedestrians and animals, allows for a range of 300 meters or nearly 1,000 feet, and avoids "dazzle" from headlights, road lights and similar intense light sources. In the fall of 2008, on the redesigned 7-series, BMW added a pedestrian detection system which flashes a caution symbol on the navigation/information screen and head-up-display when it detects pedestrians.
For model year 2013, BMW Night Vision added animal detection with Dynamic Light Spot feature for the 7-series. As soon as the remote infrared detects pedestrians or larger animals on course for collision in the dark, the system directs two separately controlled Dynamic Light Spots at them without creating an unpleasant glare. In the event of an acute risk, an acoustic warning signal is also sounded and the brakes are set to maximum standby. For the model year 2014, BMW 5-series will also have these new features.
In 2000, General Motors introduced Night Vision on the Cadillac Deville which became the first vehicle sold with such a system, however it was discontinued in 2004. This system was developed with Raytheon and worked by using an infrared sensing camera mounted behind the vehicle's grille. Infrared radiation is picked up by the sensor, processed by computer and then displayed on the windshield using a head-up display. Information is displayed as a black and white image with warmer objects in white, while cooler objects appear black. Because this system outputs a standard NTSC composite video signal and the used parts are somewhat easy and inexpensive to find, it has become a popular choice for fitting thermal night vision to other vehicles.
In the fall of 2004, Honda introduced the redesigned Legend with an optional Intelligent Night Vision system. This system detected far infrared radiation and was also the first system to offer pedestrian detection. The pedestrian detection feature alerted the driver with an audio warning and visually enclosed the pedestrian in a box on the display which was presented via head-up display.


On Call ® Extra Blood Glucose Test Strips
Specifications & Features
PRINCIPLE AND INTENDED USEThe On Call® Extra Test Strips are thin strips. The strips have a chemical reagent system.They work with the On Call® Extra Blood Glucose Meter. Together, they measure the glucose concentration in whole blood. Blood is applied to the end tip of the test strip. Then the blood is automatically absorbed into the reaction cell. This is where the reaction takes place. A transient electrical current is formed during the reaction. The blood glucose concentration is calculated based on the electrical current detected by the meter. The result is shown on themeter display. The meters are calibrated to show plasma equivalent results.On Call® Extra Test Strips are used by people with diabetes at home. They are also used by healthcare professionals. They are used to measure the amount of glucose in fresh capillary whole blood. Capillary whole blood can be from the finger, forearm, and palm. The system is also used to monitor how well the diabetes control programs work.
COMPOSITIONEach test strip has reactive and non-reactive chemicals. These chemicals are: Glucose Oxidase < 25 IU, Mediator < 300 μg, Buffer, and Non-reactive Ingredient.Each test strip vial has a drying agent.
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The objective of this study was to develop a method to assess the accuracy of an electromagnetic technology image-free navigation system for total knee arthroplasty in a leg with normal or abnormal mechanical alignment. An acrylic phantom leg was constructed to simulate tibia and femur deformation. Determination of actual leg alignment was achieved using a digital caliper unit. In the setting of normal alignment, the mean error of the system characterised as the difference between the measured computer navigation and digital caliper angles ranged between 0.8° (frontal plane) and 1.5° (lateral plane). In the setting of abnormal alignment, the mean error ranged between 0.4° (frontal plane) and 1.6° (lateral plane). Deformity had no demonstrable effect on accuracy. The study demonstrates satisfactory in vitro system accuracy in both normal and abnormal leg mechanical alignment settings.
Le but de cette étude était d'évaluer les techniques de navigation sans image par technologie électro-magnétique au cours des prothèses totales du genou. Un fantôme acrylique de membre inférieur a été construit de façon à simuler la déformation du tibia et du fémur. La différence moyenne entre la mesure par computer et la mesure instrumentale est de 0,8° dans le plan frontal et de 1,5° dans le plan latéral. Dans les cas de mauvais alignements la moyenne a été de 0,4° dans le plan frontal et de 1,6° sur le profil. Cette étude in-vitro montre que ce système est fiable aussi bien pour un membre inférieur normalement axé que désaxé.
Recent advances in computer technology and navigation systems (CAS) in total knee arthroplasty (TKA) appear useful in addressing the problems associated with intra-operative implant positioning [9, 12]. There are now many published studies on various authors’ experience with navigated TKA, most of which demonstrate a reduction in risk of implant malposition and more precise leg alignment when compared to conventional jig-based alignment guides [2, 4, 5, 7, 10, 17, 19]. However, an important distinction needs to be drawn between precision and accuracy evaluation. Whilst precision refers to agreement between repeated measurements, accuracy refers to agreement between measurements and a known true standard . Clinical trials are precision studies.
CAS technology falls broadly into two categories: image-based systems such as CT or fluoroscopy, and image-free systems. The essence of image-free systems is that they require the intra-operative registration of certain key anatomical points to determine the mechanical alignment of the tibia, femur, and the lower limb and therefore provide information about where to make the required bony cuts for implant placement. The first generation of image-free navigation systems is based on infrared technology. Recently, an innovative electromagnetic-based navigation system was developed for TKA. A multi-centre clinical trial is currently being performed to validate this new navigation tool.
The objectives of our study were: (1) to design and develop a method to assess the accuracy of the new electromagnetic image-free TKA navigation system (AxiEM, MedTronic and Zimmer, Warsaw, IN, USA), and (2) to assess its accuracy in a leg with normal and abnormal mechanical axis.
An artificial leg phantom was constructed to simulate hip and knee joints that included: (1) an articulating hip joint with femoral neck angle of 135° that allowed circumduction, a crucial movement in the CAS measurement of the femoral axis, and (2) the ability to deform femur and tibia to simulate a bone with an abnormal mechanical axis (Fig. 1). Both the femur and tibia were fabricated in two segments of acrylic with removable fixed-angle boxes located between each segment to allow 10° and 20° of deformation in valgus, varus, flexion, extension, and 10° torsion angles. An acrylic synthetic leg model (Sawbones-Pacific Laboratories, USA) was used. This model allowed for anatomical landmarks registration, AxiEM trackers placement, and CAS navigation protocol as required for the AxiEM electromagnetic system (Fig. 2). Soft tissue approximations at the knee were simulated with lateral and medial cords that were fixed to the sides of the tibial component and pulled through jam cleats on the femoral component. It is recognised that this is a poor approximation of these soft tissue constraints, but insofar as the study is concerned with bony alignment, this limitation is minimised.
A precision coordinate measurement device (FARO-Arm S06-02, FARO Technologies Inc., USA) was used for collecting coordinate data on the phantom. This multi-axis articulated digital caliper has a single point accuracy of ±0.09 mm and angular displacement accuracy of ±0.004°. Prior to each set of measurements, the device was calibrated. Precision and reproducibility of measurements was achieved by recording the positions of three coplanar holes drilled in each of the hinged segments. FARO Arm coordinate data were stored in text files and then processed using a computer program written in MATLAB (Mathworks, USA), that read the text files, established a local coordinate system for each segment, as well as a “joint” coordinate system to which each local one was related, and then calculated angles using the trigonometric relationships between the joint and local coordinate systems. This technique was verified using repeated measurement (ten repetitions) with variable coordinates, giving accuracy to within 0.06°. Simulated procedures were then performed with both a normal and an abnormal leg mechanical axis. At specific points in the procedure, information was compared between the FaroARM digital measurements and the AxiEM CAS system. Repeated serial measurements were undertaken.
The measurement protocol had four main parts. The phantom was set either neutral or with deformity. This was done by using the neutral, 10°, and 20° fixed-angle acrylic boxes and then positioning the femur-and tibia-segments either neutral or in deformity. The real deformation of femur and tibia was measured with the FARO arm which was used to confirm the angular positions of the tibial and femoral segments. This resulted in 12 points measured, i.e. three points per segment with four segments in total. During the measurement procedure the phantom was supported with iron-free clamps, which were placed to keep deflection to a minimum. The AxiEM CAS procedure was followed with standardised steps of the Zimmer minimally invasive (MIS) TKR application protocol. Small iron-free pins concave heads were inserted in the anatomical landmarks of the acrylic model. The concave pin heads allowed accurate anatomical landmarks and checkpoints registration with the AxiEM pointer. The final steps involved mounting the cutting guide to the tibia and adjusting it according to the CAS system. The cutting guide offset (coronal/frontal or sagittal/lateral tilt) was indicated by the CAS system using the AxiEM paddle (Fig. 3). The CAS figures for coronal/frontal and for sagittal/lateral alignment using the femur antero-posterior axis reference were recorded. The deformation of the various phantom segments and position of the cutting guide was then verified with the FARO arm. Analysing the data included calculating the real deformation, i.e. the angles between the two femur-segments and the two tibia-segments, and calculating the cutting guide angles, as they were measured with the FARO arm.
Each measurement was performed three times. A total of 51 measurements were performed to determine coronal/frontal and sagittal/lateral alignment with 0°, ±5°, and ±10° deformity, and 12 measurements to determine accuracy with ±10° internal and external rotation of femur and tibia segments (one at a time).
Measurement data with confidence intervals for mean error are listed in Table 1. The mean error characterises the absolute difference between the angle calculated by the CAS system and the FARO arm. In the setting of normal alignment, the mean error of the system ranged between 0.8° (frontal plane) and 1.5° (lateral plane). For the set of deformities in the frontal plane the mean error was 0.4°. The 95% confidence interval ranged between 0.1° and 0.7°. For the set of deformities in the lateral plane the mean error was 1.6°. The 95% confidence interval ranged between 1.3° and 1.9°. Deformity had no demonstrable effect on accuracy.
To date, this is the first study to assess in vitro accuracy of an image-free TKA navigation system based on electromagnetic technology. The study demonstrates a satisfactory level of accuracy of the AxiEM system in both normal and abnormal mechanical leg alignment settings.
There are now numerous published precision studies in the literature which report on the clinical outcomes of procedures performed using a navigation system [2, 15, 18, 20], including a recent study evaluating initial experience with EM technology . The majority of cadaver and clinical studies have validated the precision of these systems in specimens or patients with normal or near normal preoperative lower limb mechanical alignment, in terms of postoperative component alignment [6, 16]. This reduction in risk for component mal-alignment is well demonstrated by a recent meta-analysis of the published literature in navigated TKA, demonstrating a normal or Gaussian distribution to the summated results with reduced standard deviation from the mean when postoperative alignment is measured [15, 17]. Whilst this demonstrates the high degree of precision achievable with navigation systems, it does not identify the factor responsible for outlying results. In the biomechanically complex surgical procedure of TKA, with numerous controlling variables, it is important to attempt to independently establish the accuracy of each factor. This paper addresses the inherent accuracy of the AxiEM system. Once the accuracy of the system has been established, one additional factor which can be investigated is the effect of abnormal alignment of the limb on the accuracy of the system. The use of a phantom device to assess the accuracy of coordinate measuring systems and allow assessment of navigation systems has been described in total hip arthroplasty . In a previous paper, we described an innovative method to determine accuracy of an infra-red technology CAS navigation for TKA using a purpose-built mechanical phantom knee in conjunction with a precision coordinate measuring system . We found that the accuracy of an infra-red CAS navigation system was within 1° in setting of both normal and abnormal leg mechanical alignment. In this study, CAS based on electromagnetic technology showed similar accuracy levels.
This study has some limitations. This is an in vitro study of the system, purely in isolation, with none of the challenges posed by an operating theatre, including potential electromagnetic interference . Even by isolating the knee joint the situation is artificial. The clamping of the ball and socket hip joint removes the issue of pelvic translation, which is an important factor in the clinical setting . Nevertheless, these factors allow us to make well qualified conclusions about the inherent accuracy of the system. In terms of the materials chosen for measurement, soft tissue approximations at the knee joint model were simulated with lateral and medial cords that were fixed to the sides of the tibial component and pulled through jam cleats on the femoral component. It is recognised that this is a poor approximation of the soft tissue constraints, but insofar as the study is concerned with bony alignment, this limitation is minimised. Human error during the process of reference point registration in image-free navigation can cause a marked decrease in accuracy. In order to minimise this factor, reproducibility of reference point registration with the pointer array was achieved with the use of metal inlays for the anatomical landmarks . We tested deformation of one segment (femur or tibia) at a time to make the study model as simple as possible. We assumed that testing combined deformities would show reduction of accuracy, as well as making isolation of the responsible factor impossible. Finally, outliers in this study were probably caused by pivot algorithm errors. Unfortunately, we had no access to algorithm software of the AxiEM CAS system to verify this assumption.
In conclusion, this study shows accurate image-free CAS navigation for anatomical leg alignment in TKA using the AxiEM system. The error of the system characterised as the difference between the AxiEM and measured FARO arm angles was within 1.5°. Accuracy of electromagnetic-based CAS measured with our method appears similar to accuracy of infrared-based CAS technology for TKA. In clinical settings, we expect lower accuracy with larger variations, caused by factors such as registration errors and pivoting algorithm miscalculations.
The authors thank Dr. Cameron Walker for assistance during statistical analysis and Lawrence Anderson for the preparation of the technical drawings.


With stainless steel construction, the Cooper Atkins 26 HP-01-1 is durable enough for any and all cabinets. It’s two inch diameter dial provides a colored holding zone, with a temperature range from 100 to 175 degrees Fahrenheit. It has been made to hang or stand in any unit. Because it is NSF certified, it meets the most stringent of industry standards. With its one year limited warranty, Cooper Atkins seeks to provide customers with a high-quality product. Bakers can be assured that their well-proofed dough will give their own customers something to chew on.
Cooper-Atkins is a manufacturer and provider of quality restaurant timers, digital thermometers, refrigerator / freezer thermometers, meat thermometers, thermocouples and hygrometers. As an innovative global partners, they deliver measuring systems to help customers ensure safe food and healthy indoor environments.


Standardized targeted metabolomics using the biocrates MxP® Quant 500 kit on Agilent 6495B and 6495C triple quadrupole LC/MS systems
Metabolomics provides crucial insights into physiological mechanisms in health and disease, integrating a combined read-out of genetics, environment, and lifestyle. Mass spectrometry is the technology of choice, allowing the quantification of metabolites with high selectivity and sensitivity. The range of mass spectrometry platforms is growing steadily, and so is our kit application portfolio. For the first time, the MxP® Quant 500 kit for broad, quantitative metabolic profiling is now available for Agilent triple quadrupole (TQ) instruments.
Over the last year, the MxP® Quant 500 kit became the leading metabolomics tool for broad metabolic profiling with a focus on host-microbiome-diet interaction. This ready-to-use kit provides a simple automated workflow for the quality-controlled analysis of 630 small molecules and lipids from 26 compound classes. With more than 230 predefined metabolite sums and ratios of metabolic pathways, it facilitates advanced biological data interpretation and increased statistical power. The MxP® Quant 500 kit is the most comprehensive metabolomics kit on the market – and now it’s also accessible to Agilent users.
Optimizing for excellence
The Agilent 6495B and 6495C TQ LC/MS systems are widely used instrument bases. To adapt the MxP® Quant 500 kit to these platforms, we’ve optimized all instrumental parameters, from sample preparation setup to mass spectrometric features. A comprehensive set of defined human plasma samples was used to validate the Agilent 6495B and 6495C TQ mass spectrometers, coupled to an Agilent 1290 Infinity II UHPLC. All 13 small molecule classes were analyzed by UHPLC-ESI-MS/MS, while hexoses and all 12 lipid classes were analyzed by FIA-MS/MS.
The results were impressive:
– All detected analytes had excellent intra- and inter-batch accuracy (85-115% for LC analytes, 80-120% for FIA analytes) and precision (CV <15% for LC analytes, CV <20% for FIA analytes).
– Highly comparable results were generated using the NIST standard reference material (SRM) 1950 across multiple 6495B and 6495C TQ LC/MS systems. This also allows for pooling of data between laboratories.
– In a typical human plasma sample, 540 metabolites and lipids were found to be routinely detected (>LOD) from a small sample volume of only 10 µl. We also saw impressive results testing other sample matrices, including human feces and mouse liver homogenate.
This means that Agilent platform users can rely on the MxP® Quant 500 kit for benefits such as:
– A ready-to-use solution including all consumables and instrument-specific acquisition methods
– An automated, software-guided workflow from sample registration to data interpretation
– Fast turnaround times to guarantee high throughput analyses
– Reliable standardized quantification of the full range of metabolites and lipids.
The MxP® Quant 500 kit combined with the Agilent 6495B or 6495C TQ LC/MS system provides high-quality results with excellent reproducibility. This robust solution provides a powerful tool for broad, quantitative metabolic profiling.
All details and results of the adaptation on the 6495C TQ LC/MS system can be found in the application note 35044.
To find out more about the MxP® Quant 500 kit, please visit the product page.


The two types of weighing scales in the market are analogue and digital weighing scales. Analog is a traditional model of weighing scale while digital is the modern version of weighing scale. Both analogue and digital weighing scales have their own sets of advantages and disadvantages. The best option for you depends upon your individual requirements which can only be determined after knowing about the working and pros and cons of both kinds of weighing scales.
Analogue scales use a spring mechanism. Springs are present under the surface of the machine which contract whenever weight is put on the surface. The contracting springs rotate a spinning wheel which has weight markings on it. A pointer rests over any particular weight marking when the wheel stops spinning.
The digital scale uses digital sensors to measure weight. The load cells present in a digital scale has strain gauges which activate the sensors whenever they are strained due to the application of weight. A converter digitises the weight signal, which is displayed in the form of electronic digits on the LCD screen.
Points of Comparison
Accuracy: Digital scales use smart digital sensors which makes them more accurate as compared to analogue scales which use springs. In case of an analogue scale, you need to take some effort to see the exact weight reading on which the pointer rests. But a digital scale displays the exact weight in figures on the screen. However, even on a digital scale, there can be a percentage of error which is more in the case of cheaper models.
Ease of Use: Analog scales do not need to be turned on. You need to stand on the scale whenever you need to check your weight. There is also a need for a battery on an analogue scale. Digital scales run on batteries. There may be times when you need to check on your weight urgently, but the battery dies down, and you don’t have a spare battery. Digital scales need to be turned on and off. However, there are models which switch on and off automatically.
Durability: Analog scales use spring mechanism which tends to wear out with time. This leads to errors in readings. Moisture can also adversely affect the spring mechanism. Digital scales, on the other hand, use digital sensors which do not get damaged easily. Warranties of 1 year and more are provided on digital scales.
Calibration: Analog scales need calibration. All you need to do is twist the dial to calibrate the analogue scale. Digital scales requiring manual calibration need some efforts because the precise method as per the instructions manual must be followed. However, digital scales equipped with the auto-calibration feature are also available in the market.
Extra features: Analog scales do not have extra features other than the main task of measuring weight. Digital scales, on the other hand, can display extra information such as BMR, fat%, water%, etc. Many models can also store the data and even connect to mobile apps.
Price: Analog scales are priced more than digital scales. Digital scales with more features are even more expensive.
For more about weighing machines, follow us on https://www.weighingmachineguide.in here you will get information on latest weighing machine models and buying tips.


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[JAC262] IPM Motor Thermal Demagnetization Analysis with Incomplete Magnetization of Dy Diffusion Magnets
In this example, a motor using Dy diffused magnets the thermal demagnetization resistance of the Dy diffused magnets with a coercive force distribution when there is incomplete ma…
[JAC225] Induced Voltage Analysis on Memory Motors Using Variable Magnets
In this example, the change in motor characteristics are checked as the memory motor variable magnet magnetization is changed using the three-phase coil current. One example of mo…
[JAC030] Magnetization Field Evaluation of an SPM motor
In this example, carry out SPM motor's magnetization to obtain the magnetization field and magnet's surface magnetic flux density.
[JAC129] Analysis of a PM Stepper Motor Accounting for Magnetization
In this analysis, a magnetization device model is created and a magnet is magnetized. The magnetization distribution and surface magnetic flux density of the magnetized magnet, an…
[JAC126] Magnetization Analysis Accounting for Eddy Currents
This Application Note presents how to obtain the magnetization field distribution accounting for eddy currents in the magnetic material to be magnetized, the eddy current density …
[JAC055] Integrated Magnetization Analysis of an IPM Motor
This Application Note explains how to determine the changes that occur in a magnetizing field if the making current is changed during magnetization, as well as how to obtain the i…
[JAC079] Analysis of an Effect of Magnetic Field Orientation on Magnetization
This Application Note explains how to obtain a magnet’s surface magnetic flux density distribution while accounting for the orientation and magnetization processes.
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Analysis of simultaneous generation of argon and krypton laser lines in ion lasers filled with argon-krypton mixture
Wojciech Kamiński , Jerzy Kęsik , Piotr Warda
AbstractArgon ion lasers can generate several strong laser lines in short wavelength region of visible spectrum (green and blue light). Krypton ones offer the generation of laser lines in long wavelength region (red and yellow light). Both gases have complementary generation ranges thus ion lasers filled with mixture of argon and krypton are attractive laser sources for many applications. In most of these applications the only one laser line selected with dispersion element within the resonator are used at one time. After removing the dispersion element the simultaneous generation of many wavelengths is possible. Unfortunately in this working mode of ion lasers the negative effect of competition between laser lines appears. The effect has the most significant influence on the generation of yellow Kr II 568 nm line which is very needed for some applications due to small number of other available strong laser sources for this light range. Generation conditions of this line is strongly hampered when ion laser simultaneously generates other laser lines thus in this laser working mode this laser line completely disappears. We have observed the exact reason of this effect and we have described the way to improve laser generation conditions of Kr II 568 nm line which makes possible to obtain the laser generation of this line simultaneously with other laser lines. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
|Corporate author||Institute of Microelectronics and Optoelectronisc (IMiO)|
|Publication size in sheets||0.5|
|Book||Woliński Wiesław, Jankiewicz Zdzisław, Romaniuk Ryszard (eds.): Proceedings of SPIE Laser Technology 2012: Progress in Lasers, vol. 8702, 2013, P.O. Box 10, Bellingham, Washington 98227-0010 USA, SPIE, ISBN 9780819494931, 176 p., DOI:10.1117/12.2021407|
|Score|| = 10.0, 01-01-2020, BookChapterMatConfByConferenceseries|
= 15.0, 01-01-2020, BookChapterMatConfByConferenceseries
|Publication indicators||= 0|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.


Fujifilm Corp developed a magnetic tape whose storage capacity is 5 Tbytes per cartridge and data transmission speed is 240 Mbytes per second.
It has started shipping the "Tape Cartridge for StorageTek T10000C," which uses the new magnetic tape, to Oracle Corp. Its storage capacity is more than five times higher than that of the "StorageTek T10000B," which is the predecessor of the T10000C, and three times higher than those of the "LTO Ultrium 5" tapes. Fujifilm claims that the T10000C uses a magnetic tape with the world's highest capacity.
The magnetic tape is targeted at enterprise systems using mainframes. And Oracle started selling it Feb 1, 2011.
This time, Fujifilm increased storage capacity by employing a barium ferrite (BaFe) magnetic material as a recording material for the tape. In general, the storage capacity of a magnetic tape is increased by microparticulating a magnetic material to enhance recording density. However, it is difficult to increase the storage capacity of a "metal magnetic material," which is currently the mainstream material (It is difficult to maintain the coercive force of a metal magnetic material when it is microparticulated).
On the other hand, a BaFe magnetic material can maintain a higher coercive force, better frequency characteristics and low noise characteristics even when it is microparticulated, compared with a metal magnetic material, Fujifilm said. The capacity of 5 Tbytes was realized by applying the BaFe magnetic material thinly and lubricously, it said.
In addition to the high storage capacity, Fujifilm claims that the T10000C has a storage stability of 30 years or more. This can be realized because the BaFe magnetic material is an oxide and chemically stable. Therefore, the tape is hardly affected by the environment where it is used, and its magnetic properties do not change much over time.
Moreover, Fujifilm enhanced the durability of the cartridge of the tape, enabling to load/unload the drive 25,000 times or more.


Dwyer Instruments offers many styles of Pitot tubes, which are a commonly used sensor for monitoring air velocity and flow rate in heating, ventilation, and air conditioning.
Pitot tubes are based on Bernoulli’s equation, which states an increase in the speed of a fluid occurs simultaneously with an increase in dynamic pressure and a decrease in static pressure. Pitot Tubes sense the dynamic pressure of the fluid flow at a particular point and were invented by French Engineer Henri Pitot in the early 18th century.
Wall mount humidity sensors for building automation system (BAS) applications are produced and sold by several different companies and have a reputation of poor accuracy despite specifications from suppliers. There is a rational reason why these instruments appear to read outside of their stated accuracy, which in turn causes users to be frustrated with the results.