arXiv:nucl-ex/0612020v1 18 Dec 2006
Absolute Polarization Measurements at RHIC in
the Coulomb Nuclear Interference Region
K.O. Eyser∗, I. Alekseev†, A. Bravar∗∗, G. Bunce‡,§, S. Dhawan¶, R. Gill‡,
W. Haeberli?, H. Huang‡, O. Jinnouchi††, Y. Makdisi‡, I. Nakagawa‡‡,§,
A. Nass§§, H. Okada‡‡,¶¶, E. Stephenson∗∗∗, D. Svirida†, T. Wise?, J. Wood‡
and A. Zelenski‡
∗University of California, Riverside, CA 92521, USA
†Institute for Theoretical and Experimental Physics (ITEP), 117259 Moscow, Russia
∗∗University of Geneva, 1205 Geneva, Switzerland
‡Brookhaven National Laboratory, Upton, NY 11973, USA
§RIKEN BNL Research Center, Upton, NY 11973, USA
¶Yale University, New Haven, CT 06520, USA
?University of Wisconsin, Madison, WI 53706, USA
††KEK, Tsukuba, Ibaraki 305-0801, Japan
‡‡RIKEN, Wako, Saitama 351-0198, Japan
§§University of Erlangen, 91058 Erlangen, Germany
¶¶Kyoto University, Kyoto 606-8502, Japan
∗∗∗Indiana University, Bloomington, IN 47408, USA
Abstract. The Relativistic Heavy Ion Collider at Brookhaven National Laboratory provides polar-
ized protonbeams forthe investigationof the nucleonspin structure.Forpolarimetry,carbon-proton
and proton-proton scattering is used in the Coulomb nuclear interference region at small momen-
tum transfer (−t). Fast polarization measurements of each beam are carried out with carbon fiber
targets at several times during an accelerator store. A polarized hydrogengas jet target is needed for
absolute normalization over multiple stores, while the target polarization is constantly monitored
in a Breit-Rabi polarimeter. In 2005, the jet polarimeter has been used with both RHIC beams. We
present results from the jet polarimeter including a detailed analysis of backgroundcontributions to
asymmetries and to the beam polarization.
Keywords: Elastic Scattering, Polarimeter, Polarized Protons
PACS: 24.70.+s, 29.25.Lj, 29.27.Hj
tivistic Heavy Ion Collider (RHIC). Measurements of beam polarizations utilize scatter-
ing processes. Fast measurements are based on proton-carbon scattering off carbon fiber
targets , for which the necessary normalization is provided from elastic proton-proton
scattering with a polarized hydrogen gas jet target. At high energies, the asymmetries
are driven by the electromagnetic spin-flip amplitude at small four-momentum trans-
fer (10−3< |−t| < 10−2). Asymmetries are small (few percent) and contain unknown
contributions from hadronic amplitudes in this so-called Coulomb nuclear interference
region. The existing data, therefore, not only serve as a necessary input to other RHIC
experiments, but on the other hand can also be used to further confine the helicity am-
~ 80 cm
to the interaction point. In routine operation only one RHIC beam hits the target, while the other beam is
Detector setup of the jet polarimeter at RHIC. The six detectors are centered with respect
plitudes φ1−φ5and the hadronic spin-flip contribution in particular .
SETUP AND ANALYSIS
The jet polarimeter is located at one of the collision points in the RHIC accelerator and
reflects the kinematics of elastic proton-proton scattering at small |−t|. It consists of
a polarized hydrogen atomic jet target with a Breit-Rabi polarimeter  and a set of
six separate detectors each of 16 silicon strips, see figure 1. The target polarization is
prepared in an inhomogeneous magnetic field in combination with a radio-frequency
transition unit and constantly monitored (not shown in the figure). The hydrogen molec-
ularcontenthas been determinedand is corrected for.Theeffectivepolarizationamounts
to Ptarget= (92.4±1.8)%.
The detectors are centered with respect to the interaction point of the proton beam
with the target. In this geometry, eight downstream strips on each detector can detect
elastically scattered recoil protons when one RHIC beam hits the target. In routine
operation, one of the two RHIC beams is displaced, so the respective eight non-signal
strips can be used to estimate the background fraction below the elastic signal peak.
The silicon detectors are read out with waveform digitizers (running at 420 MHz
and synchronized with the RHIC clock) that send the pre-processed ADC spectra to
the DAQ-PC. Two different α-sources (Am and Gd) are used for energy calibration
and estimation of the entrance window thickness of the detectors. Additional time of
flight offsets are individually adjusted for each strip using the pronounced proton signal.
Particle identification is based on time of flight and energy. Elastic scattering further
correlates the detector geometry, i.e. the scattering angle, and the small recoil energy of
theproton. A time-of-flightcut ofafew ns removesthemajorpart ofpromptbackground
events below 5 MeV.
In 2005, one of the two RHIC beams was centered on the jet target for several days to
are expected asymmetries from formal descriptions in terms of helicity amplitudes  in the Coulomb
nuclear interference region scaled with the polarization values.
Target and beam asymmetries as functions of recoil energy TR. The solid and dashed lines
accumulate enough statistics for a precise measurement of the beam polarization. Both
beams have been measured repeatedly over the course of a few weeks.
For the determination of the RHIC beam polarization, a set of four different vertical
polarization combinations of target and beam is used. The yields are then combined to
separate asymmetries resulting from the beam and target polarizations. While a certain
polarization direction would result in a specific left-right asymmetry in the detectors,
respective yields can be coupled with their opposite polarization directions in order
to remove detector acceptances and efficiencies and luminosity effects, . The beam
polarization Pbeamis then derived from the ratio of the measured asymmetries εbeamand
εtargetand the known target polarization Ptarget:
The analyzing power AN= ε/P is not flat in the considered t-region and, therefore,
the beam polarization was determined in separate steps of the recoil energy TRbefore
calculating the weighted mean. Also, the kinematic correlation of the detector strip
position and the recoil energy suppresses the background outside of the considered
energy range, where no elastic signal is seen.
The ratio of asymmetries is very robust with regards to background contributions
to the yields, as long as the background has no pronounced polarization dependence.
Background fractions can be as large as 7% in certain energy ranges, which affect the
beam polarization only in second order.
RESULTS Download full-text
Target and beam asymmetries have been measured as functions of energy of the recoil
proton. Figure 2 shows the typical peak of the asymmetries (and the analyzing power) at
TR≈1.5 MeV in the CNI region from a subset of the data. The asymmetry ratio between
1.0 and 4.0 MeV is used to determine the beam polarization. Lower and higher recoil
energies are discarded due to increased acceptance asymmetries and highly increased
background. Also, the asymmetries in figure 2 are compared to the expected shape of the
analyzing power ANfrom a formal description in terms of helicity amplitudes  that
has been scaled with the target and beam polarizations. The shown curves are neither
fitted to the analyzed data, nor do they include contributions from hadronic spin-flip
In 2005, beam polarizations of nearly 50% have been measured in RHIC with good
statistical accuracy. Systematic errors were estimated from the background yields from
empty target measurements and subdivision with respect to separate proton bunches in
to the polarization directions of bunches and calculating the resulting asymmetries.
Background contributions have been identified from molecular content in the jet tar-
get, from beam gas, and from the displaced beam that is threaded around the target. No
significantbeam or target polarizationdependence has been observedin thebackground,
which is uniformly distributed over the detector halves within the statistical uncertain-
ties. The effect on the determination of the beam polarization has been estimated by
purposefully widening the signal region on the detectors, this way increasing the back-
ground by factors of up to four and consecutivelylowering the beam and target asymme-
tries. The ratio of asymmetries, on the other hand, is largely unaffected by the growing
background and an upper limit of ∆P/P = 1.1% has been assigned to the beam related
background below the signal. The hydrogen molecular content of the target causes an
additional uncertainty that is already taken into account in the target polarization error.
Fastbeam polarizationmeasurementsat RHIC are carried outwithtwo carbon polarime-
ters . Absolute polarization normalization is done alternatingly with a polarized hy-
drogen jet target. Beam polarizationsofnearly 50% havebeen measured in thelatter half
of the 2005 run. Total uncertainties have reached the accuracy that experiments in the
RHIC spin programm have called for. The existing data, also, have been used to further
constrain the knowledge of hadronic spin-flip amplitudes at√s =13.7 and 6.9 GeV .
1. I. Nakagawa, these proceedings (2006).
2. H. Okada et al., Phys. Lett. B638, 450 (2006) and H. Okada, these proceedings (2006).
3. H.G. Gaul and E. Steffens, NIM A316, 297 (1992).
4. G.G. Ohlsen, P.W. Keaton, Nucl. Instrum. Meth. 109, 41 (1973).


- Automatic online device that integrates sample preparation, measurement and sampling without human intervention.
- The same analyzer can control up to 3 sampling points for carbon and sulfur analysis
- The same analyzer can control up to two sampling points
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- Can be used for SO3 analysis in hot raw meal, clinker and cement


quality MRM methods to obtain the best sensitivity and dynamic range for peptides from a panel of putative protein biomarkers for cardiovascular disease. For candidate proteins previously detected in proteomics experiments, MRMs were designed based on peptide MS/MS spectra. For the remaining candidates, MRMs were developed either by in silico design, based on gene or protein sequences, or by targeted, direct detection in plasma using the MIDAS workflow.
The MIDAS workflow provides a straight-forward link between the genomics/proteomics biomarker discovery experiments and high throughput, quantitative MS validation, because no previous experimental data on the individual proteins of interest is required to develop an assay. This quantitative LC-MRM method profiles 53 high and medium abundant proteins in human plasma (Figure 1). Proteins down to ~1 μg/mL concentration in plasma can be reliably detected in both digested and depleted/digested human plasma, producing a dynamic range of ~5 orders of magnitude in this single method (Figure 1, inset). Peptide MRM measurements in plasma digests thus provide a robust platform for quantitative protein biomarker early stage validation.
MIDAS Workflow for Method Development:
During an MRM experiment, the triple quadrupole capability of the mass spectrometer transmits the parent ion and subsequent fragment ion with high sensitivity and selectivity. The first mass analyzer is set to transmit only the mass of the peptide parent ion (Q1 at unit resolution) into the collision cell. Only one of the sequence ions of the peptide, generated by fragmentation in the collision cell, is passed through the second mass analyzer (Q3 at unit resolution) to the detector (Figure 2).
This MRM experiment can be used as a survey scan in a MIDAS workflow to selectively detect low level peptides in complex mixtures. The detection of the pePage: All 1 2 3 4 5 Related biology technology :1
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Infrared 850 nm LED
- Emission peak at 850 nm matched to silicon detectors and opto ICs
- Narrow irradiance pattern
- High temperature range of -40 to 125 °C
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Transmissometer and optical elements therefor
||Transmissometer and optical elements therefor
||February 3, 1987
||June 17, 1983
||Rose; Thomas H. (County of Wake, NC)
||Eastern Technical Associates, Inc. (Raleigh, NC)|
||Lusignan; Michael R.
|Attorney Or Agent:
||Bell, Seltzer, Park & Gibson
||356/243.2; 356/434; 356/438
|Field Of Search:
||356/433; 356/434; 356/437; 356/438; 356/439; 356/243
|U.S Patent Documents:
||3850529; 3994601; 3997271; 4017193; 4050814; 4126396; 4222641; 4247205; 4294524; 4333724; 4364639; 4422729; 4432649
|Foreign Patent Documents:
||A transmissometer includes electronic shutters for interrupting the transmitted and reference light beams at selected locations and at selected time intervals for establishing the various modes of operation of the transmissometer. The electronic shutters take the form of liquid crystal displays that are selectively energizable to either a clear or an opaque condition. The transmissometer also includes an electronic stepwise light attenuator located in the path of the light beams. The attenuator includes a body and multiple liquid crystal display segments uniformly distributed throughout the body, with the segments being independently energizable to provide stepwise opacity.
||What is claimed is:
1. An optical device comprising means for establishing a transmitted beam and a reference beam, means for subjecting the transmitted beam to a sample condition for attenuationthereby, detector means positioned for receiving each of said beams and generating a signal representative of a condition of the beams, and an electronic stepwise light attenuator located in the path of the reference beam, said attentutor having anoptical field and comprising multiple liquid crystal display elements, each element being substantially uniformly distributed throughout the optical field and being independently energizable to place it in either a clear or an opaque condition, saidelements being so positioned as to cooperate in their respective clear/opaque conditions to produce stepwise attenuation of the reference beam at predetermined and repeatable opacity steps, including multiple intermediate values between 0% and 100%opacity.
2. An optical device as set forth in claim l including a zero shutter located in the path of said reference beam.
3. An optical device as set forth in claim 1 wherein the liquid crystal display elements are formed as alternating strips.
4. An optical device as set forth in claim 1 wherein the liquid crystal display elements are formed as concentric circles.
5. An optical device as set forth in claim 1 wherein the liquid crystal display elements are formed as radiating strips.
6. An optical device as set forth in claim 1 wherein the liquid crystal display elements are formed as spirals.
7. A transmissometer for continuously monitoring the opacity of gases passing through a duct, e.g. flue gases passing through a smokestack, and being characterized by non-mechanical electronic light interruption and attenuation for measurementand calibration purposes, said transmissometer comprising:
a primary unit for delivering a collimated light beam across the duct and receiving a reflected beam from the opposite side of the duct, said primary unit being adapted for mounting on one side of the duct;
a retroreflecting unit adapted for mounting on the opposite side of the duct from said primary unit and including retroreflecting means for reflecting the light beam emanating from the primary unit back to the primary unit by reflectionsubstantially along the direction of incidence;
said primary unit including:
a light source;
optical means associated with said light source for establishing a collimated light beam;
a beam splitter located in the path of said light beam and inclined with respect to the light beam to split the beam of light into (i) a transmitted beam that traverses the duct to said retroreflecting means and is reflected back to the primaryunit and (ii) a reference beam;
a photodetector located in the path of both the reference beam and the reflected transmitted beam for generating a signal representative of the light incident thereon;
an electronic zero shutter comprising a liquid crystal display selectively energizable to produce either a clear or an opaque condition, said zero shutter being located in the path of the reference beam between said beam splitter and saidphotodetector;
a stepwise light attenuator located in the path of the light that constitutes the reference beam, said stepwise light attenuator comprising multiple electronic display elements each of which is selectively and independently energizable incooperation with the other elements to produce stepwise attenuation of the reference beam at predetermined and repeatable opacity steps;
an electronic system shutter comprising a liquid crystal display selectively energizable to provide either a clear or an opaque condition, said system shutter being located in the path of the transmitted light beam between said beam splitter andsaid retroreflector means;
an electronic chopper shutter comprising a liquid crystal display selectively energizable to provide either a clear or an opaque condition, said chopper shutter being located between the light source and the beam splitter;
controls means for selectively energizing the electronic shutters and stepwise light attenuator to establish various multiple modes of light interruption and attenuation for measurement and calibration purposes; and
means for processing the signals generated by the photodetector in the various modes.
8. A transmissometer as set forth in claim 7 wherein the electronic display elements are formed as alternating strips.
9. A transmissometer as set forth in claim 7 wherein said beam splitter comprises a partial mirror inclined at approximately 45.degree. to the collimated light beam emanating from said optical means to establish the transmitted beam in adirection substantially normal to such collimated light beam, and to establish the reference beam as a colinear continuation of the non-reflected portion of such collimated light beam.
10. A transmissometer as set forth in claim 9 wherein said primary unit includes branch means that is oriented substantially normal to the transmitted beam for receiving the reference beam after it passes through the beam splitter, said branchmeans including said zero shutter and a front surface mirror oriented normal to the reference beam for reflecting the reference beam back to the beam splitter partial mirror where a portion thereof is reflected to said photodetector along a pathsubstantially colinear with that of the transmitted beam.
11. A transmissometer as set forth in claim 7 including an electronic span shutter comprising a liquid crystal display selectively energizable to produce either a clear or an opaque condition, said span shutter being located directly ahead ofsaid photodetector.
12. A transmissometer of the type used for measuring the opacity of a sample and having a beam splitter establishing a transmitted beam and a reference beam, means for receiving the transmitted and reference beams and generating signalsrepresentative of the intensity of the light incident thereon, and beam shutters located at selected points in the optical paths of said beams for interrupting the beams to establish various transmissometer modes of operation, said shutters comprisingelectronic liquid crystal displays selectively energizable to produce either a clear or an opaque condition at each display at selected time intervals.
13. A transmissometer as set forth in claim 12 including an electronic stepwise light attenuator located at a selected location in the path of at least one of said beams, said attenuator comprising a body and multiple liquid crystal displaysegments distributed throughout the body, said segments defining segment sets that are independently energizable to place each segment set in either a clear or an opaque condition, thereby providing a light attenuator having stepwise opacity determinedby the conditions of said segment sets.
14. An optical device comprising means for establishing a light beam, means for subjecting the light beam, or some divided portion thereof, to a sample condition for attenuation thereby, detector means for generating a signal representative of acondition of the beam, or portion thereof, and at least one beam shutter for interrupting the light beam, or portion thereof, to establish multiple modes of operation for said optical device, for example, measurement and calibration modes, saidelectronic shutter comprising an electronic liquid crystal display selectively energizable to produce either a clear or an opaque condition at selected time intervals.
15. A method of calibrating a transmissometer of the type that establishes a reference beam incident upon a photodetector thereof, said method comprising the steps of:
directing the reference beam of the transmissometer so that prior to reaching the photodetector it is incident upon an electronic stepwise light attenuator having multiple electronic display elements, wherein each element is substantiallyuniformly distributed throughout the optical field of the attenuator and each element is independently energizable to place it in either a clear or an opaque condition;
selectively energizing certain ones of said display elements at predetermined intervals so as to produce stepwise attenuation of the reference beam at predetermined and repeatable opacity steps, including multiple intermediate values between 0%and 100% opacity; and
transmitting the signals generated by the photodetector to a location remote from the transmissometer and processing said signals to provide calibration for said transmissometer.
||BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to transmissometers for measuring the opacity of fluid samples. In particular embodiments the invention relates to a transmissometer incorporating electronic shutters and an electronic stepwise light attenuatorwhich are selectively actuated to place the transmissometer in the several light transmission modes necessary for opacity measurement, calibration and correction for drift.
2. Description of the Prior Art
Environmental considerations have given rise to regulatory requirements for the continuous monitoring of the opacity of smokestack effluents. The most reliable systems for providing this continuous monitoring are know as double-passtransmissometers. These devices include a light source on one side of the smokestack and an aligned retroreflector on the other side. A collimated light beam passes through the smokestack, is reflected by the retroreflector so that it passes throughthe smokestack again and then is picked up at selected time intervals by a photodetector whose output signals are representative of the opacity of the effluent through application of Beer's Law.
It is well known that transmissometers must be calibrated, preferably by calibration to a zero attenuation reference and upscale attenuation references. These conditions are achieved by directing a reference light beam from the source to thephotodetector without allowing the beam to enter the smokestack.
A further consideration is that the transmissometer must be provided with means for compensating for "drift" caused by variations in the intensity of the light source, changes in the sensitivity of the photodetector, temperature changes, etc.
In order to deal with the calibration and drift problems, devices of the prior art have incorporated mechanical means for diverting optical paths and attenuating light in the optical path. These mechanical aspects of prior devices have provenquite complicated, and provide an aspect of unreliability that is undesirable in transmissometers which are usually placed at remote locations.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a transmissometer that overcomes the disadvantages associated with transmissometers incorporating the above-mentioned mechanical components.
In one aspect, the invention may be defined as an optical device that establishes a transmitted beam and a reference beam and directs the transmitted beam into a sample where it is attenuated. The device also includes a detector for generating asignal representative of a condition of the beams when they are incident on the detector, and an electronic stepwise light attenuator located in the path of the light constituting the reference beam. The attentuator comprises a body and multiple liquidcrystal display segment sets distributed throughout the body, with the segment sets being independently energizable to place each segment set in either a clear or an opaque condition.
The display segment sets preferably comprise a grid of relatively long, thin segments that are substantially uniformly distributed throughout the body so as to provide uniform dispersion of the radiation incident thereon. Other geometricpatterns such as concentric circles, radiating lines and spirals may be used.
In another aspect the invention comprises a transmissometer for continuously monitoring the opacity of gases passing through a duct. The transmissometer includes a primary unit adapted for mounting on one side of the duct to deliver atransmitted light beam across the duct and to establish a reference beam, and a retroreflecting unit adapted for mounting on the opposite side of the duct to reflect the transmitted beam back to the primary unit. The transmissometer includes a pluralityof beam shutters located at selected points in the optical paths of the transmitted and reference beams for interrupting the beams to establish various transmissometer modes of operation necessary to measure the gas opacity, calibrate and account fordrift. The shutters comprise electronic liquid crystal displays selectively energizable by on-off pulses to produce either a clear or an opaque condition at each display at selected time intervals. The transmissometer may also include an electronicstepwise light attenuator, as defined above, located at a selected location in the path of the light beams.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be more fully understood from the following detailed description thereof taken in connection with the accompanying drawings, in which
FIG. 1 is a perspective view of an exploded transmissometer of the invention in operative position with respect to a smokestack for continuously monitoring the opacity of the smokestack effluents.
FIG. 2 is a schematic representation of a transmissometer of the invention with all of the electronic shutters and the electronic stepwise attenuator in the clear condition.
FIG. 3 is a view similar to FIG. 2 showing the transmissometer in the zero mode.
FIG. 4 is a view similar to FIGS. 2 and 3 showing the transmissometer in a calibration mode for an upscale check.
FIG. 5 is a view similar to FIGS. 2-4 showing the transmissometer in the span mode.
FIG. 6 is a view similar to FIGS. 2-5 showing the transmissomter in a measurement mode.
FIG. 7 is a plan view of a most preferred embodiment of the variable opacity stepwise attenuator of the invention.
FIG. 8 is a sectional view taken substantially along line 8--8 of FIG. 7.
FIG. 9 is a sectional view taken substantially along line 9--9 of FIG. 7.
FIGS. 10-12 are plan views of first, second and third alternative embodiments of the variable opacity stepwise attenuator of the invention.
FIG. 13 is a block diagram of the signal flow chart for the transmissometer illustrated in FIGS. 1-6.
DETAILED DESCRIPTION OF THE INVENTION
While the present invention will be described hereinafter with particular reference to the accompanying drawings, it is to be understood at the outset of the description which follows that it is contemplated that the present invention may bevaried in specific detail while still achieving the desirable characteristics and features of the present invention. Accordingly, the description is to be understood as a broad enabling teaching directed to persons skilled in the applicable arts, and isnot be be understood as restrictive.
Referring to the drawings, and particularly to FIG. 1, there is shown a double-pass transmissometer 10 constructed in accordance with the present invention. Transmissometer 10 includes a primary unit 12 adapted for mounting on one side of asmokestack 14 and a retroreflecting unit 18 adapted for mounting on the opposite side of the smokestack.
Referring to the schematic illustration of FIG. 2, the transmissometer will now be described initially without reference to the electronic shutters and stepwise attenuator so as to first set forth the paths of the light beams. Primary unit 12includes a light source 20 that emits light that is collimated into a light beam 22 by means of optical means 24 of any suitable type known in the art, for example, a condensing lens and aperture arrangement.
Light beam 22 next falls on a beam splitter in the form of a partially reflective mirror 32 that is inclined to beam 22. In the illustrated embodiment, mirror 32 is inclined at 45.degree. with respect to beam 22 and is half silvered so as toreflect approximately one half of beam 22 in a direction normal to beam 22 to establish a transmitted beam 36. The remaining half of beam 22 passes directly through mirror 32, remaining colinear with beam 22, and establishes a reference beam 40.
The transmitted beam 36 is projected across smokestack 14 through first and second windows 42, 44 and is incident upon a retroreflector 48, for example, a corner cubed mirror that reflects light incident thereon back along its direction ofincidence. The reflected transmitted beam travels back through smokestack 14 to the beam splitter where approximately one half of the beam passes through the splitter in the direction of a photodetector 50 and associated photopic filter 51 of a typewell known in the art.
The reference beam 40, after being split from beam 22, enters a branch 52 that is oriented substantially normal to the path of the transmitted beam. Branch 52 includes a front surface mirror 56 that is postioned substantially normal to thereflected beam for reflecting the reference beam back to the beam splitter where a portion thereof is reflected to photodetector 50 along a path substantially colinear with that of the transmitted beam.
The foregoing description of the beam paths is solely for the purpose of setting forth some of the elements of the transmissometer 10 and to establish the uninterrupted light paths that would occur in a situation where all of the electronicshutters and the stepwise attenuator are clear as represented in the schematic illustration of FIG. 2. However, in the various modes of operation discussed below, the electronic shutters and stepwise attenuator are actuated in various fashions toprovide opaque conditions at selected points in the light paths.
Transmissometer 10 includes four electronic shutters as follows: (a) a chopper shutter 60 located between the light source 20 and the beam splitter; (b) a system shutter 62 located in the path of the transmitted beam between the beam splitter andthe retroreflector; (c) a zero shutter 64 located in the path of the reference beam between the beam splitter and the photodetector; and (d) a span shutter 66 located in the paths of the reference beam and the reflected transmitted beam just prior totheir incidence upon the photodetector.
Each of the electronic shutters comprises a liquid crystal display that is selectively energized or non-energized to place the display in either a clear or an opaque condition. The shutters may take a form similar to that of Model No. 39992606displays manufactured by Hamlin Company of Lake Mills, Wis. which incorporate a pair of parallel polarized plates separated by a liquid crystal. In the non-energized state the crystal rotates the incident light 90.degree. to establish an opaquecondition for the display. In the energized state the light is not rotated by the crystal, thus establishing a clear condition.
Transmissometer 10 also includes an electronic stepwise light attenuator 70 located proximate to photodetector 50 in the path of both the reference beam and the reflected transmitted beam. As best shown in FIG. 7, attenuator 70 comprises aplanar body incorporating multiple liquid crystal display segment sets A,B,C that are distributed throughout the body. The segment sets are independently energizable to place each segment set in either a clear or an opaque condition, thereby providing alight attenuator having stepwise opacity determined by the conditions of the segment sets. In the illustrated embodiment, attenuator 70 is substantially rectangular and is divided into four substantially equal portions of surface area. The firstportion comprises the clear strip areas 74 residing between the respective liquid crystal display segments. The remaining three areas are formed by the three sets of alternating rows of display segments.
When all three segment sets A,B,C are in a clear condition, attenuator 70 is substantially clear, i.e., 0% opaque. By energizing the segment sets so that one is opaque, the attenuator becomes 25% opaque; two opaque segment sets render theattenuator 50% opaque; and three opaque segment sets render the attenuator 75% opaque.
The display segment sets A,B,C may be formed from parallel polarized plates 80, 82 (FIG. 8) separated by a liquid crystal 84 as explained above in connection with shutters 60, 62, 64, 66. The display segments are mounted on a clear plate 88 thatserves as the carrier plate for the displays and establishes the clear one-fourth area of attenuator 70 (FIGS. 7 and 9). In the illustrated embodiment, segments A,B,C are relatively long, thin segments uniformly distributed in alternating fashionthroughout the body of attenuator 70 so as to provide uniform dispersion of the light incident thereon.
FIGS. 10-12 illustrate three alternative embodiments of stepwise light attenuators constructed in accordance with the present invention.
FIG. 10 shows an attenuator 90 comprising a planar body incorporating liquid crystal display segments in the form concentric circles. The segments define three segment sets A',B',C' that are independently energizable.
FIG. 11 shows an attenuator 100 having multiple liquid crystal display segments in the form of radiating strips. The segments define segment sets A", B", C" that are independently energizable.
FIG. 12 illustrates yet another attenuator 110 incorporating spirals formed from liquid crystal displays. Each spiral defines segments and independently energizable segment sets A"', B"', C"', each of said sets being a complete spiral.
Each of the attenuators of FIGS. 10-12 is illustrated as having three independently energizable portions comprising one fourth of the surface area of the attenuator with remaining portions 94, 104, 114 comprising the remaining one-fourth surfacearea, such that stepwise attenuation of 0%, 25%, 50%, 75% opacity is achieved. It will be appreciated that the attenuators illustrated in FIGS. 7 and 10-12 have been shown as divided into one fourth areas; however, other equal divisions of the area orunequal divisions may be desirable and are within the spirit and scope of the invention.
While attenuator 70 has been illustrated as positioned immediately ahead of photodetector 50, it may be positioned anywhere in the path of the light that constitutes reference beam 40. For example, attenuator 70 may be placed in the branchcontaining light source 20 in a position adjacent chopper shutter 60 in which case it may serve to block light beam 22 (which is the basis for and therefore constitutes reference beam 40.) Attenuator 70 may also be placed in branch 52 that containsmirror 56 and zero shutter 64. It will be appreciated that when attenuator 70 is so placed in branch 52 the reference beam 40 will make a double pass through the attenuator.
The various operating modes of transmissometer 10 are illustrated in FIGS. 3-6. FIG. 3 schematically illustrates the zero mode wherein the transmitted light beam is blocked by means of the opaque condition of system shutter 62. In the zeromode, as well known to those skilled in the art, the reference beam is allowed to impinge unattenuated upon the photodetector to provide a reference for zeroing the system.
FIG. 4 illustrates a calibration mode for performing an upscale check on the system. In the calibration mode system shutter 62 blocks the transmitted beam. The calibration mode differs from the previously discussed zero mode in that stepwiseattenuator 70 is selectively actuated to one of the stepwise opacity conditions, for example 25%, 50% or 75% opaque, so as to permit an upscale check of the system.
FIG. 5 illustrates the span mode that presents a "dark current" to the detector. Each of the electronic shutters 60, 62, 64, 66 is placed in its opaque condition and the stepwise attenuator 70 is put at its maximum opacity of 75% opaque. Itwill be appreciated that the light to photodetector 50 will be essentially blocked by the opaque condition of shutters 60, 62 and 64; however, span shutter 66, an optional but preferred element, helps assure that the photodetector indeed sees a darkcurrent.
FIG. 6 illustrates the measurement mode wherein the reference beam is blocked by the opaque zero shutter 64 while allowing the transmitted beam to make a double pass through the smokestack and impinge upon photodetector 50. In the measurementmode, chopper shutter 60 is provided with an on-off pulse so that it alternates between clear and opaque, thus providing a comparison of the intensity of the reflected transmitted beam to the ambient light conditions at the photodetector.
The signal conditioning circuit 120 of transmissometer 10 will now be described with reference to FIG. 13. Circuit 120 includes a system controller in the form of a solid state timer 122 that controls the states of shutters 60, 62, 64, 66 andattenuator 70 to place the transmissometer in the various modes discussed above, thereby determining the incident light on photodetector 50. The output of photodetector 50, in the form of an analog chopped signal, is directed to an analog/digitalconverter 126 that converts the signal to a digital chopped signal. This signal is conditioned to an unchopped signal by means of a buffer 130 and is fed to a multiplexer 136. Zero, span, measurement and upscale signals are received by a centralprocessing unit 140 and a span standard 144, which together control the output of a data log 150.
The signals that are produced by photodetector 50 include: a simulated source zero signal (FIG. 3), upscale linearity check signals (FIG. 4), simulated source span signals (FIG. 5), measurement signals (FIG. 6) and ambient light interferencesignals (FIG. 6, with shutter 60 opaque and/or light 20 turned off). As noted above, these signals are generated at predetermined intervals controlled by system controller 122.
The purpose of the ambient light interference signal is to determine the light incident on photodetector 50 when no light is being received from the light source. The interference signal is, therefore, generated by light scattered into thetransmissometer from the stack, and may be sunlight or other ambient light in the system. The ambient light would make the apparent transmission higher than the actual transmission of light through the smokestack. Therefore, the "off" portion of thechopped signal is subtracted from the "on" or "light" portion of the signal to give true system transmittance.
The purpose of the simulated source zero and simulated source span signals are to establish an electronic zero intersect and slope to convert the photodetector output signal to a transmission of light measurement, as well known in the art.
The three upscale linearity check signals that are produced by operation of stepwise light attenuator 70 serve to verify that the transmissometer is operating correctly and is linear. These values must fall within established limits or a flagwill be placed on the data.
Conversion of data to opacity readings is performed according to the following formula, 100-% transmission=% opacity and is accomplished by a simple subtraction of the value of the transmissometer from 100 in digital systems, or by signalinversion in analog systems.
While the present invention has been described in connection with illustrated embodiments it will be appreciated that modifications may be made without departing from the true spirit and scope of the invention.
* * * * *
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Nanoscale spatially resolved infrared spectra from single microdroplets†
Droplet microfluidics has emerged as a powerful platform allowing a large number of individual reactions to be carried out in spatially distinct microcompartments. Due to their small size, however, the spectroscopic characterisation of species encapsulated in such systems remains challenging. In this paper, we demonstrate the acquisition of infrared spectra from single microdroplets containing aggregation-prone proteins. To this effect, droplets are generated in a microfluidic flow-focussing device and subsequently deposited in a square array onto a ZnSe prism using a micro stamp. After drying, the solutes present in the droplets are illuminated locally by an infrared laser through the prism, and their thermal expansion upon absorption of infrared radiation is measured with an atomic force microscopy tip, granting nanoscale resolution. Using this approach, we resolve structural differences in the amide bands of the spectra of monomeric and aggregated lysozyme from single microdroplets with picolitre volume.


Optical strain gauge extremely stable in thin plate
Taking measurements using an optical fibre (fibre optic sensing) offers unprecedented possibilities when compared to conventional electronic measuring. This is mainly due to the wave characteristic of light: think of aspects such as resolution and multiplexing, with a good example being the ‘optical strain gauge’. TNO Science and Industry has developed the principle for a high-frequency multi-channel measuring system based on Fibre Bragg Grating. This system can measure any quantity that can be translated into thermal or mechanical strain on the fibre. Technobis has now developed it into a product that is ready for the market, the Fibre Bragg Grating Interrogator. The greatest challenge, however, was to make the system extremely stable.


RADAN® is GSSI’s state-of-the-art post-processing software. With its modular design, this program allows users to select the processing functions that best suit their professional needs. RADAN is Windows™ based, providing a familiar and easy-to-use environment for all levels of experience.
The 3D module provides enhanced 3D viewing options ins a single dialog box. Users can stretch, shrink or zoom in on files as desired for customised presentations results. the 3D module also allows the entire data cube to be ” sliced and diced” along various x, y and z planes. This allows the user to easily interpret complex areas and to make sense of the data. With this module’s simple, intuitive click-and-drag interface, viewing multiple slices and rotating the data for better view has never been easier.
The 3D module also shows multiple interactive views of 2D and 3D data simultaneously and to create shapes (pipes, drums, lines etc) in the GPR data, which can then be exported for integration with CAD drawings. This way, the data can be presented to the Client in familiar, easy to understand format. These 3D options provide users with unparalleled data interpretation and presentation capabilities.
BridgeScan Module: Map Bridge Deck Deterioration
The BridgeScan Module for RADAN 7 allows users to;
Identify rebar, calculate concrete cover over rebar on new deck structures, and perform deterioration mapping. This module incorporates GSSI’s patented data analysis method designed for post-processing and analysis that is streamlined specifically for bridge deck data. The BridgeScan Module is ideal fro large bridge deck structures with typical two-layer orthogonal grid reinforcement patterns.
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The RoadScan Module for RADAN 7 is designed for use with horn (air-launched) antennas. This module uses a signal calibration technique that measures significant layer interpretation amplitudes from the pavement data and calculates the propagation velocity of he GPR signal through the pavement layer. This allows pavement thickness, base thickness and other pavement structure properties to be calculated without the need for ground-truth (core) data.
This Software module includes automatic and interactive layer interpretation, automatic and interactive pavement thickness and provides output of signal and position information to an ASCII database for roadway condition and assessment.


Milling, boring, drilling and tapping All of these processes can be done in one setup, increasing productivity and processing quality. Centralized control by numerical control system, 5-axis linkage, AC servo drive system, rack and pinion drive system and roller linear guide.
|Distance of Spindle to worktable||Max||mm||780|
|Rotary Table (C)||nX360°|
|Spindle Rotation Speeds||r/min||10-4000|
|In Feeding Speeds||Longitude (X)||mm/min||10-8000|
|Rotatry Table (C)||r/min||0-5|
|Fast In Feeding||Longitude (X)||mm/min||12000|
|Rotary Table (C)||r/min||0-8|
|Spindle Servo Power||Kw||30|
|In Feeding Servo Power||Longitude (X)||Nm||35|
|Rotary Table (C)||Nm||35|
|Max Worktable Load Weight||T||6|
1. Keep the components cleaned
Minimize the opening of the numerical control cabinet and the door of the power cabinet. During processing, a large amount of oil mist, dust or even metal powder will be generated to prevent it from falling on the circuit board or electronic device in the numerical control system, resulting in a decrease in insulation resistance between components, or even Damage to components and boards.
2. The ventilation system is smooth
The fan is indispensable for any processing equipment that integrates oil, electricity and gas. The ventilation of the core processing part is inseparable from the participation of the fan. Regularly check that each cooling fan on the CNC cabinet is working properly and that the duct filter is clogged. If too much dust accumulates on the filter net and is not cleaned up in time, the temperature inside the CNC cabinet will be too high, which is very large damage to the machining center.


Transcript of "Micro-nanosystems for electrical metrology and precision instrumentation"
Micro-nanosystems for electrical metrology and precision instrumentation A. Bounouh1, F. Blard1,2, H. Camon2, D. Bélières1, F. Ziadé1 1 LNE – 29 avenue Roger Hennequin, 78197 Trappes, France, email@example.com 2 LAAS/CNRS – Université de Toulouse - av du colonel Roche, 31077 Toulouse cedex 4, FranceAbstract: This paper present results of work undertaken for sinusoidal current of amplitude IRMS and frequency ω, theexploring MEMS capabilities to fabricate AC voltage AC voltage presents, according to the current IRMS, areferences for electrical metrology and high precision maximum:instrumentation through the mechanical-electrical coupling max VAC = V pi = 8kd 2 / 27C 0 (1)in MEMS devices. Several first devices have been designedand fabricated using a Silicon On Insulator (SOI) Surface where C0 is the capacitance at x = 0 and k the springMicromachining process. The measured MEMS AC voltage constant (Fig.2).reference values have been found to be from 5 V to 100 V ina good agreement with the calculated values performed with 1.0Coventor and Comsol finite elements software. These tests 0.8structures have been used to develop the read-out electronicsto drive the MEMS and to design new devices with 0.6 VRMS/Vpiimproved characteristics. 0.4Keywords: MEMS, AC voltage, Pull-in effect, SOI. 0.2 1. INTRODUCTION 0.0 0.0 0.2 0.4 0.6 0.8 1.0 1.2 I RMS /I max From MEMS devices made up of membranes, beams or seesaw structures, several applications in electrical Fig. 2. MEMS Voltage versus IRMS biasing current metrology are possible as AC and DC voltage references, RF-DC converters, current reference, low frequency This point can be used as a stable AC voltage reference voltage divider and RF and microwaves power sensors [1- since its relative variation in this point depends only on the 3]. Such devices are made of micro-machined electrodes square of that of the current: of which one at least is movable thanks to the application ∆VRMS/Vpi~ -3/2 (∆I/Imax)2 (2) of an electrostatic force between the two electrodes, inversely proportional to the square of the gap. For In order to have the required stability for primary and voltage references, one uses the pull-in effect of a electro- secondary metrology fields and precision instrumentation mechanical microsystem having a movable electrode (some parts in 107 per year), special designs and (Fig.1) architectures featuring low sensitivity with respect to strain and geometrical dispersion have to be investigated, as well kx Movable as technological processes featuring low residual stress and Electrode high repeatability. x 2. DESIGN AND FABRICATION OF TEST DEVICES Fixed d-x electrode The first set of MEMS structures were based on a silicon Fig. 1. MEMS with variable capacitor disk plate featuring different configuration of the suspending springs to ensure a controlled piston modeThe stable displacement x of the movable electrode is motion. The structures have been designed using alimited to the third of the gap named d. In the characteristic Coventor and Comsol softwares. Fig.3 shows the layoutsvoltage-displacement, the pull-in voltage Vpi corresponds to of the movable part of the structures that have beenthe maximum voltage applied to the capacitive MEMS designed and used for the tests. The first device (1) is abeyond which the two electrodes are put in contact. 500 µm-radius disk plate with three curved 1300 µm-longHowever, if the previous structure is now biased with an AC springs of 10 µm width. Device (2) is very similar to (1)VIII Semetro. João Pessoa, PB, Brazil, June 17 – 19, 2009
design and has the same dimensions, only the curved part coefficient of the MEMS based AC voltage. First C-V of the springs in (2) are attached together forming a ring curves have been carried out on the MEMS of structure (1) of 10 µm width, which slightly increases the stiffness of by using a RLC-meter. An external DC bias voltage was the structure and then Vpi. The aim of this design is to applied to the MEMS and the capacitance was measured improve the vertical guidance of the movable plate. The with an AC voltage of 0.1 V at a frequency of 100 kHz. same disk plate as previously (r =500 µm) is used for As shown in Fig.5, the MEMS exhibits a pull-in effect at Vpi forming the last design (3) having four straight springs = 1.9 V. However, another mechanical state corresponding (360 µm × 10 µm). to Vpi=4.5 V can also be observed. This last point is to be compared to the calculated value of 5.26 V. (1) (2) (3) 70 100 kHz Hold on 60 Capacitance (pF) 50 Fig. 3. MEMS test structures. 40 Vpi- Vpi+The MEMS have been fabricated with TRONIC’s process 30available as a process foundry through the Multi ProjectWafer. It consists of a Silicon On Insulator (SOI) surface 20 -2.5 -2 -1.5 -1 -0.5 0 0.5 1 1.5 2 2.5micromachining process. The SOI top layer is a 60 µm thick Bias Voltage (V)monocrystalline silicon layer used for the mechanicallyactive layer, exhibiting excellent mechanical characteristics Fig. 5. C-V characteristic of the MEMS of structure (1) at 100 kHz signal frequency(it can tolerate up to 1010 cycles without any crack or fatigue). The silicon dioxide layer acting as insulator and spacerdefines the gap of 2 µm height and the silicon substrate To drive the MEMS to the pull-in voltage for defining thefeatures 450 µm thick acting as the fixed electrode. Silicon ac voltage reference, we have developed the read-outwafers resistivity is in the range of 0.02 Ω.cm obtained by a electronics of Fig.6. As the MEMS have to be biased withhigh boron p-type doping of 2.1018 cm-3. an AC current, it is used in the feedback loop of the A1To ensure the stability of the MEMS, a vacuum hermetic amplifier consisting in a voltage-to-current converter. Thesilicon wafer level packaging protects the die. The final amplifier A1 should have a great product gain-bandwidthstructure is composed by the assembly of the SOI wafer to work up to some hundreds kHz. However, this kind ofwhere the MEMS is realized and a silicon wafer acting as a components has not small voltage offset and polarisationcap for protecting the MEMS. The non-sealed areas are current, this is why we use a low frequency precisiondefined by partial etch of a silicon dioxide initially realized amplifier A2 to fix the DC out-put voltage at zero. Figureand the metallization define the sealing areas for assembly. 6 shows the frequency response of both amplifiers A1 andAfter assembly, via holes are realized to allow electrical A2, which make this electronics usable in the range 10contact to pads. kHz –1 MHz.The previous layouts have been used for elaborating theMEMS structures. Fig.4 shows photos of the three MEM=15pF 0fabricated MEMS. Let us note that on the same die there are Rp=22MΩ -10 C 1=15pF3 MEMS hermetically packaged and 3 other MEMS in a no A1 -20hermetic packaging. This configuration makes it possible to R5=10MΩ R2=10kΩ -30 -40assess the packaging effect on the stability of the AC A2 C2=150nF -50voltage references. C3=150nF R3=10kΩ -60 10 100 1kHz 10 100 1 MHz 10 (1) (2) (3) Fig. 6. Voltage-to-current read-out electronics Measurements of the MEMS out-put RMS voltage in function of the current IRMS flowing in the MEMS (U-I curve) have been carried out at frequencies ranging from 10 kHz to 200 kHz. Fig.7 displays the characteristics Fig. 4. MPW MEMS structures fabrication MEMS out-put voltage of structure (1) versus the current . IRMS at 100 kHz. All curves show the same maximum of the out-put voltage corresponding exactly to the pull-in voltage Vpi = 1.9 V observed in the C-V curves. 3. MEASUREMENT RESULTSThe multi-physics characterization platform has been set upin order to verify the model parameters and to perform theappropriate characterization to determine the stabilityVIII Semetro. João Pessoa, PB, Brazil, June 17 – 19, 2009
i) definition of deposit type, etching and thickness of the 1.970 layers; ii) drawing of the masks; iii) Mesh of the different 100 kHz Vpi 1.960 regions. The calculations have been performed with the electromechanical formulation of Coventor software. For MEMS Out-put Voltage (V) 1.950 each structure, the displacement x of the movable electrode 1.940 is calculated by varying the DC voltage applied between the movable electrode and the silicon substrate. Fig.9 shows for 1.930 the 10 V structure the simulations and the calculated 1.920 displacement according to the DC voltage, which gives a simulated pull-in voltage at x=0.66 µm corresponding to 1/3 1.910 of the gap of 2 µm defined by the thickness of the SOI 1.900 silicon dioxide. 29.0 30.0 31.0 32.0 33.0 34.0 Current I RMS (µA) 12 V pi = 10 V Fig. 7. U-I curve of MEMS (1) at 100 kHz 10 DC applied voltage (V) 8 4. DESIGN AND FABRICATION OF ENHANCED 6 DEVICES 4 New MEMS structures have been designed with the aim to get samples showing lower pull-in voltages for the best performance of the read-out electronics. Indeed, as the 2 MEMS capacitor is used in the feedback loop of the A1 amplifier consisting in a voltage-to-current converter, this 0 amplifier should have a great product gain-bandwidth to 0 0.2 0.4 0.6 0.8 Displacement (µm) work up to some hundreds kHz. In this case, the most powerful amplifiers have voltage supply about ±15 V at most. Two structures were targeted to have pull-in Fig. 9. Coventor modelling of 10 V structure and pull-in voltage voltages of 5 V and 10 V. The layout of the design is calculation. depicted in Fig.8 and it is the same for both MEMS. It is based on a silicon disk plate with straight suspending The calculated parameters of the two structures are springs. The 5 V device is a 1105 µm-radius disk plate summarized in table 1 where the capacitance C0 at x=0, the with three 1072 µm-long springs of 10 µm width. 10 V spring constant k, the resonance frequency and the pull-in device has the same diameter of the movable plate with voltage are given. 884 µm length of the springs. Both structures are guarded by a 65 µm width silicon ring to avoid the effect of any Table 1. Calculated characteristics of the new structures leakage currents. The improvement carried out in these new structures concern the effective capacitance of the movable part, which becomes much higher than the Structures C0 (pF) k (N/m) f0 (kHz) Vpi (V) parasitic capacitance. Indeed, the value of the movable capacitance is now of 22 pF. 5V 22.8 1437 10 5.5 10 V 22.8 437 18 10 The MEMS have been fabricated with TRONIC’s process with the Silicon On Insulator (SOI) surface micromachining process previously used for the test structures. Each fabricated die contains the two types of MEMS (5 V and 10 V) and a vacuum hermetic silicon wafer level packaging has been used to protect the die. However, we have also fabricated structures where the packaging is not hermetic to compare both systems and to evaluate the effect of the environmental conditions. Fig.10 shows a photo of the two fabricated MEMS, which are on the same die there. For each MEMS, we have contact pads corresponding to the movable electrode, the guard, the silicon cap protecting the die and the silicon substrate. Let us note that for the hermetic die, the pads are larger and Fig. 8. Layout of the enhanced MEMS contribute more in the effective capacitance of the MEMS.The design of the structures is carried out following 3 steps:VIII Semetro. João Pessoa, PB, Brazil, June 17 – 19, 2009
300 250 Capacitance (pF) 200 150 100 50 0 -5 -3 -1 1 3 5 Fig. 10. Photo of the 5V and 10V MEMS structures Bias voltage (V)Deep Level Transient Spectroscopy (DLTS) measurements Fig. 12. C-V curve of the 5V MEMS (HK11) at 100 kHz signal frequencyhave been carried out on these MEMS to analyze thedynamic behaviour of the movable plate by measuring the The U-I curves corresponding to the MEMS out-put RMScapacitance change in time. voltage in function of the current IRMS flowing in the MEMS have been carried out at a frequency of 100 kHz. Fig.13 42.5 displays this characteristic for the 5V MEMS of the HK11 42.0 die. The maximum of the out-put voltage corresponds at 41.5 approximately 4.1 V, which is exactly the value of the pull- Capacitance (pF) 41.0 in voltage Vpi observed in the C-V curves. 40.5 0V 40.0 39.5 4.11 39.0 V pi 38.5 4.09 MEMS out-put voltage (V) 38.0 3 V step 4.07 37.5 0 5 10 15 20 4.05 Time (ms) 4.03 Fig. 11. 5V MEMS capacitance versus time showing the response of the structure to a voltage step of 3 V. 4.01 3.99Fig.13 represents the response of the 5V MEMS of the die 3.97named HP11 to a DC voltage step of 3 V during 10 ms. Themembrane oscillations represented by the oscillations of the 3.95MEMS capacitance are clearly observed over a time period 25 27 29 31 33 I RMS (µA)lower than 5 ms beyond which the movable electrodebecomes stable. Moreover, the membrane behaves in thesame way when establishing and stopping the voltage step. Fig. 13. U-I curve of the 5 V MEMS (HK11) at 100 kHzThis indicates that the system is not very damped since theMEMS in HP11 die are hermetically sealed in a vacuum. 4. CONCLUSIONThe resonance frequency of the MEMS determined from theDLTS measurements is of 2.8 kHz to be compared to theexpected value of 10 kHz for this structure. The stability of the AC reference voltage corresponding to the maximum of these curves is under test by using aTwo other hermetic samples named HK6, HK11and one no specific read-out electronics based on the amplitudehermetic named NH15 have been used for the first C-V and modulation of the main biasing ac signal. The results will beU-I measurements. Fig.12 presents a C-V curve for the presented at the time of the conference as well as theHK11 sample where the 5 V MEMS has been tested. assessment of the whole MEMS fabrication. The results ofIt exhibits a pull-in voltage around 4 V, which is lower than this assessment will be used to validate the models, tothe calculated value of 5.5 V. The same value is obtained for understand the dispersions and to propose consolidatedall the other dies (hermetic and no hermetic). For the 10 V architectures more robust with respect to the dispersion inMEMS, the pull-in effect occurs at 7 V, which is once again the MEMS fabrication.lower than the expected value of 10 V. The slight differencebetween the measured and calculated values indicates thatthere is a more important buckling of the movablemembrane than expected.VIII Semetro. João Pessoa, PB, Brazil, June 17 – 19, 2009
REFERENCES  B.P. van Drieënhuizen, “Integrated Electrostatic RMS to Converter”, Thesis, 1996.  M. Suhonen et al, “AC and DC Voltage Standards Based on Silicon Micromechanics, CPEM98, pp. 23-24, 1998.  EMMA project report, Information Societies Technology, IST200028261EMMA, 2005.  H. Camon, C. Ganibal, “Advantages of alternative actuating signal for MEMS actuators”, Sensors & Actuators A136 N°1, pp.299-303, 2007.R. Abraham, J. E. Marsden, T. Ratiu, Manifolds, Tensor Analysis, and Applications. 2 ed. New York, Springer-Verlag, 1988.VIII Semetro. João Pessoa, PB, Brazil, June 17 – 19, 2009


We’re still covering basic prerequisites to building a robot, such as safety and where to buy parts. In this chapter, you’re going to learn about a vital piece of measurement equipment that every robot builder has by their side, the digital multimeter. Multimeter features are broken into groups: must-have, nice-to-have, and optional. The chapter concludes with an analysis of three multimeters.
A multimeter is a required tool for robot building. You will need a multimeter to perform the experiments and build the projects in the chapters that follow. (See Figure 4-1 for an example of a multimeter).
With a multimeter, ...


Quality Academy is an international accredited service company based in Alexandria/Egypt with core business devoted to quality and safety consulting, training, supplier audits, supply chain management, industrial manufacturing compliance (inspection) and automation, includes ISO Standards Certification
based in Alexandria, EGYPT.
Cirrus Research plc is a world leading manufacturer and supplier of sound level meters, noise meters, noise dosimeters, environmental noise monitoring systems and acoustic transducers. Our products are used across and wide and diverse range of applications including Occupational Noise, Industrial Hygiene, Environmental Noise Measurement, Vehicle Noise Testing and Airport ...
Distributor in EGYPT.
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Innovo FR201 non-contact digital Infrared Forehead Thermometer
The Innovo INV-FR201 non-contact digital infrared forehead thermometer has been specifically designed to measure body temperature from the forehead. It can also be use to provide an estimation of room temperature and surface temperature of an object, such as a milk bottle. The thermometer is safe, accure and simple to use.
Quick and convenient
Elegant one-button operation
Fever alert and memory recall
Portable and convenient


Desiccant-based Air Handling Units (AHU) canguarantee significant technical andenergy/environmental advantages with respectto conventional systems, especially when theregeneration of the desiccant material isobtained by means of a renewable energysource, such as solar energy.An emerging technology exploiting solar energyis represented by PVT (PhotoVoltaic/Thermal)collectors, which simultaneously provideelectricity and heat.In PVT collectors electrical efficiency may beimproved, with respect to conventional PV cells,when the outlet temperature of the cooling fluidis sufficiently low. Therefore PVT systems areoften used for low-temperature heat demand.However, PVT collectors may also show highvalues of both thermal and electrical efficiency.This occurs in case of Concentrating PVT(CPVT) collectors equipped with triple junctionPV cell, capable to achieve ultra-high electricalefficiencies (> 20 %) even when the fluid outlettemperature is around 100 °C. An interestingapplication of such CPVT collectors is thedesiccant cooling, as the regenerationtemperature of silica-gel desiccant wheelsranges between 40 °C and 70 °C.A test facility has been located in Benevento(Southern Italy), in which a silica-gel desiccantwheel is inserted in a hybrid AHU, in which thedehumidified process air is cooled by an electricchiller. The AHU has been simulated by meansof TRNSYS software.In this paper, the desiccant-based AHU hasbeen coupled with a novel CPVT, consisting of aparabolic trough concentrator and a lineartriangular receiver. For this component a modelin TRNSYS has been developed too. Electricenergy produced by the CPVT collector is usedto power the auxiliaries of the AHU and thechiller, while thermal energy is used to heat theregeneration air flow. Energy and environmentalperformance of the overall system areevaluated, in terms of primary energy savingand emission reduction with respect to areference case.
|Titolo:||SIMULATION OF ENERGY AND ENVIRONMENTAL PERFORMANCE OF A DESICCANT-BASED AHU INTERACTING WITH A CPVT COLLECTOR|
TARIELLO, Francesco (Corresponding)
|Data di pubblicazione:||2013|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|


- Halogen amperometric total residual oxidants sensor is accepted by IMO’s GESAMP subcommittee as equivalent to the traditional DPD test
The acceptance by IMO’s Joint Group of Experts on the Scientific Aspects of Marine Environment Protection (GESAMP) that Halogen’s amperometric total residual oxidants sensor is equivalent to the traditional test N, N-diethyl-p-phenylenediamine (DPD) reagent test for residual reagent in treated ballast water discharge, is a big step forward for the US manufacturer, says an article published in Riviera.
Without repeating final approval test
The acceptance opens the way for ballast water management system manufacturers to switch from DPD instruments to the reagentless halogen amperometric sensor without repeating the final approval testing.
The US Coast Guard (USCG) took a similar position in 2021. In 2022, USCG issued the first TRO substitution of Halogen’s amperometric sensor for a DPD instrument used in type-approval testing.
Online monitoring of TRO
According to Halogen Systems president Michael Silveri, “This makes the change from a DPD instrument to Halogen’s amperometric sensor straightforward.
While a case by case is required by the approval authority, repeating the initial type-approval testing is not required. With our new side stream system, a DPD Instrument can easily be retrofitted to use a Halogen amperometric sensor.”
According to IMO GESAMP STW report, “… the Group’s conclusion that it would recognise amperometric TRO sensors as practical alternatives to DPD colorimetric sensors for use in the online monitoring of TRO in future BWMS applications…”
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Starrett Outside Micrometer Set, 0-12"
The Starrett S436 Outside Micrometer Set includes 12 micrometers, 11 standards, adjusting wrench, in case. The most popular precision micrometers used by skilled workmen worldwide. Anvils sized at 6.35mm (.250") diameter for ease of use on larger work. This model features 0-12" measuring range. Combination ratchet and speeder for uniform pressure and quicker adjustment. Recommended for mechanics, automotive service and machine shops, toolrooms, inspection departments and wherever gaging involves a wide range of measurements. SET, 0-12”, .001” Grad, Carbide Faces, Ratchet Stop, Lock Nut involves a wide range of measurements.
- The most popular precision micrometers used by skilled workmen worldwide
- Accurate, rugged, and easy to use
- All sets come with attractive, protective case, which keep micrometers and standards together, readily accessible
- Hard and stable one-piece friction thimble permits one-hand operation of micrometer and uniform contact pressure
- Balanced frame and thimble design ensure easy handling
- Gracefully designed tapered frame for use in narrow slots and tight places
- Micro-lapped measuring faces
- Starrett No-glare satin chrome finish on thimble and sleeve minimizes annoying surface glare under bright lights and resists rust
- Anvils sized at .250" (6.35mm) diameter.
|Micrometer Type||Outside Micrometer Set|
|Set Range||0 - 12"|
|Micrometer Sizes||1,2,3,4,5,6,7,8,9,10,11,12 in|
|Lock Nut Type||Knurled Ring Type|
|Standards Included||1,2,3,4,5,6,7,8,9,10,11 in|
|Case Type||Wood Case|


The Comparison Microscope
A Mainstay of Forensics
The comparison microscope is the mainstay of forensic science allowing two objects or samples to be compared side by side.
While the primary use of this type of instrument is criminology as in ballistics, other scientific fields including paleontology and archaeology utilize these special compound microscopes.
What is a Comparison Microscope?
microscope from Leica-
Comparison scopes are two compound light microscopes that sit side by side and allow the user to view both specimens through a center eyepiece that displays both images.
Compound microscopes are microscopes that use multiple lenses to magnify an image for study.
The images from the comparison instrument can also be transferred to a computer monitor, television screen or sent via the Internet to a remote computer.
The ability to view two samples simultaneously allows them to be meticulously compared to see if they are identical or different.
The primary use of these types of dual microscopes is in forensics, a discipline that uses science and technology to help solve crimes by providing factual evidence and linking crime scene evidence to a suspect or location.
Tools create specific marks, bullets have signature marks, hair can be human or animal and using two compound microscopes to study a known sample against a collected piece of evidence can confirm an objects origin.
Having multiple eyepieces, image magnifications ranging from 6x to 400x depending on the microscope model and image viewing options including left or right views only, side by side views of both samples and superimposed viewing places one image on top of the other for comparison.
A number of forensic microscope companies use components from the primary microscope providers, including Leica, Zeiss and Olympus. Leeds Forensic Systems offers a number of systems that use Olympus and Zeiss optical components.
- Leica - "motorized comparison macroscope is used for a wide range of forensic investigations including ballistics, toolmark, and document comparison. Intelligent Automation combines with outstanding ergonomic design.The five apochromatically-corrected macro objectives feature a high numerical aperture and built-in, adjustable iris diaphragms for top optical performance.Different imaging modes (split image, superimposed image and combined image) are set at the press of a button. This convenient platform provides increased reproducibility, accuracy, and efficiency."
- FX C is a motorized macroscope that provides detailed study of a small section of a larger object. Intelligent Automation software provides a wide range of computerized options including virtual microscopy.
- Leeds Forensic Systems - Provides a wide range of forensic microscopes many utilize Olympus BX microscopic components that provide ergonomic eyepieces, uniform illumination and a variety of observation tubes.
- Leeds Firearms and Toolmarks - Microscope systems provide built in aperture diaphragms, large viewing area and ergonomic design with single knob focus.
With image magnification of 5.5x to 55x as well as 6x to 102x and 16:1 zoom ratio and built-in aperture diaphragms, the Trace Evidence Comparison Microscope is a modular unit that allows it to be utilized by all forensic aspects of comparison microscopy.
Some units provide a 22mm view and are capable of many contrasting options including bright and dark fields, phase contrast, polarized light and fluorescence. Dual view components allow systems to be used as a training microscope or for multiple-person viewing.
- Ken-a-Vision - (see below) Provides a cordless teaching comparison instrument that can be used for macro and micro samples.
View options include independent and dual side viewing with illumination from the top or bottom.
A full charge allows this teaching forensic instrument to be in use without power for forty hours.
- Forensic Comparison Microscopes - Offers three comparison instruments specifically designed for use in the field of criminal investigation.
Their 10x by 144x magnification unit is portable and includes a USB digital camera system with ports for still photo or videotaping.
The 40x by 600x forensic unit offers multiple illumination options including light direction allowing this unit to be used for metallurgical and epi-illumination applications.
The 40x by 1000x compound unit includes both CCD video and USB still photo camera, unique screen options permit image reversal plus left and right side image views at 100%.
This unit has a clean thin-line screen division allowing better comparison of samples without compromising clarity.
- GX Microscopes: Units feature integrated micro and macro systems that includes two tilt-able stages, vernier controls and comes with multiple eyepieces and objective lenses.
Accessories for units may include digital camera systems, and holding brackets for all types of items including bullets and cartridges that can be mounted to the microscope.
Amazon.com offers comparison microscopes that are well priced and are solidly built by good manufacturers.
Using a comparison microscope provides factual evidence that can help solve crimes, pinpoint historic dates and confirm signatures.
Before this instrument was designed, people used their eyes for sample comparison studies, these types of compound light microscopes provide the tool to accurately confirm if two samples are identical.
Interesting read: Forensic Pathology.
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We present results of 32-month project using absolute gravity measurements to monitor groundwater in an arid to semi-arid region in northern New Mexico. Over 100 permanent gravity stations have been established in the groundwater basin. A-10 absolute gravity meters, manufactured by Micro-g LaCoste, Inc., have been used to monitor long-term gravity changes in the groundwater basin. Over fifty A-10 sites have been established; other gravity sites have been established by reference to the primary A-10 sites using Scintrex CG-3M and CG-5 relative gravimeters. Geodetic-quality GPS surveys were used to directly measure any possible elevation changes at the gravity sites. At good sites, away from regions where we expect changes due to groundwater removal, reproducibility of the A-10 measurements is ±4 μGal. Gravity stations were observed approximately every six months over the course of the project. Systematic changes in both gravity and station elevation have been observed at a number of sites. On the basis of our observations, we can delineate three areas which appear to have systematic changes in storage. We conclude that the use of high-precision absolute gravity measurements, in conjunction with precise observations of station elevation, can provide useful information for evaluating groundwater storage changes over time.


CHENGDU JING XIN MICROWAVE TECHNOLOGY CO., LTD
Model No.: JX-PD
Certification: RoHS, ISO
Support Network: GSM
Information content: Data
Brand: Jing Xin
Place of Origin: Chengdu, China
Supply Ability: 80000PCS/Year
Certificate: ISO 9001 / EN 9100
HS Code: 851770900
JINGXIN's 3 way cavity power divider 698-2700 MHz:,it can be customized according to customers`s needs.SM/FM/UHF/UMTS Passive Microwave Wireless 3 way cavity power divider/power splitter n-female connector.Power dividers (also power splitters and, when used in reverse, power combiners).Power dividers and splitters are used in a wide range of applications, such as: transmission line fault testing, power combining, source leveling, ratio measurements, power splitting, and critical signal processing applications that require minimal insertion loss and high port isolation.
Model NO.: JX-PD
We are manufacturer and OEM
1.Low Insertion Loss
3.Short Lead Time and Fast Delievery
OUR F: DC to 40GHz, up to 2000W power.
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Copyright © 2020 CHENGDU JING XIN MICROWAVE TECHNOLOGY CO., LTD All rights reserved.


Part Number: TA8220H
Function: 30W, BTL x 2CH AUDIO POWER AMPLIFIER
Package: HZIP17 Pin type
The thermal resistance of TA8220H package designed for low thermal resistance, has high efficiency of heat radiation.
The temperature rise of chip can be reduced, and the influence from the degradation of the features due to the temperature rise at the high output can also be reduced.
Block Diagram :
1. Low Thermal Resistance
2. High Power
3. Low Distortion Ratio
4. Low Noise
TA8220H Datasheet PDF Download
Other data sheets are available within the file: TA8220


Air change rates in a cross-ventilation model were measured from the decay curves of video image signals obtained by the step down method assuming perfect mixing of tracer mists inside the spaces. Wind tunnel test results led to the following conclusions. 1) Ray extinction due to lighting scattering did not affect the measurement accuracy of the air change rates in the two-dimensional model. 2) Tracer mists in a diameter between 0.25 μ m and 2.0 μ m produced the same measurement accuracy. 3) With oil mists as a tracer, laser powers of more than 0.5 watts were enough to visualize the flow patterns in the model. 4) The air change rates were proportional to the reference velocities. 5) The proposed method measured the air change rates with an error of less than 9 %. This was the same accurate measurement as the tracer gas procedure using a high-speed hydrocarbon analyzer
A new technique for measuring air change rates in a cross-ventilation model using the step down method of video image signals.
Sweden, Stockholm, KTH Building Services Engineering, 1998, proceedings of Roomvent 98: 6th International Conference on Air Distribution in Rooms, held June 14-17 1998 in Stockholm, Sweden, edited by Elisabeth Mundt and Tor-Goran Malmstrom, Volume 2


Triaxial accelerometers for high precision, high durability applications
06 October 2011
Kistler Type 8688A series instrument grade triaxial accelerometers are suitable for applications requiring high-precision, low-frequency measurements and high-durability packaging. The low mass, hermetically sealed (IP68) titanium cube measures just 12.5mm and combines Kistler’s PiezoBeam technology with an integrated PiezoTron charge converter to produce a triaxial accelerometer that has an exceptional sensitivity-to-size ratio.
Available in 5, 10 and 50g versions, the 8688A series accelerometers combine an 0.5 to 5,000Hz frequency range with excellent phase accuracy and shock survivability, a specification suited to a wide variety of applications ranging from aerospace ground vibration testing; flight test; structural dynamics and vibration assessments to automotive laboratory testing and vehicle ride assessments.
The ground isolated mounting clip can be used in three sensor orientations for mounting flexibility. The primary mounting surface has a 10-32 UNF threaded hole for use with a ground isolated screw-on adhesive or magnetic mounting base.
As an option, the accelerometers can be supplied with TEDS (Transducer Electronic Data Sheets) IEEE1451.4 capability.
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This Simple switching power supply for 15 Watt can be used to power any load up to 15 … 20 watts and has smaller dimensions than a similar, but with the step-down transformer, operating at a frequency of 50 Hz.
The power supply to terminal single-cycle pulsed RF transmitter. Transistor oscillator assembled, clocked at 20 … 40 kHz (depending on settings). Frequency adjustable capacitance C5. Elements VD5, VD6 and C6 form a chain running oscillator.
In the secondary circuit after the rectifier bridge is an ordinary linear regulator on the chip, which allows the output voltage is fixed, regardless of changes in the input network (187 … 242 V).
In the Simple switching power supply for 15 Watt scheme used capacitors C1 and C2 type K73-16 for 630 V, W – K50-29 440; C4 – K73-17V, 400; C5 – K10-17, C6 – K53-4A at 16; C7 and C8-type K53-18 to 20 V. The resistors can be arbitrary. Zener diode can be replaced by VD6 KS147A.
Pulse transformer T1 is performed on the ferrite core M2500NMS-2 or M2000NM9 Sh5h5 size (cross-section of the magnetic coils at the location of 5×5 mm with a gap in the center). Winding wire is made brand PEL-2. Winding 1.2 turns of wire contains 600 0.1 mm in diameter, 3-4 – 44 turns of 0.25 mm diameter, 5-6 – 10 turns in the same wire as the primary winding.
If necessary, the secondary windings may be several (in the diagram shows only one), and for the oscillator to observe the polarity phase windings 5-6 in accordance with the scheme.
Setting the converter is to obtain a steady excitation oscillator when the input voltage from 187 to 242 B. Elements requiring the selection, followed by an asterisk “*”. Resistor R2 can be par 150 … 300 ohms, and capacitor C5 – 6800 pF … 15000. To reduce the size converter for less withdrawn in the secondary circuit of power ratings electrolytic filter capacitors (NW, C7 and C8) can be reduced. Their value is related to load capacity ratio:
P : power to the load circuit, W;
Um -: the amplitude of the rectified voltage (acting for the incident on the input line voltage amplitude is 242 342);
Fc : frequency, to calculate the SP it takes 50 Hz;
ΔU : maximum ripple of rectified voltage range allowed by the applicable type of capacitor (taken from the handbook: the case for C50-29 he is 10 … 14% [L16], ie 34 V).
The design of the Simple switching power supply for 15 Watt device should include the installation of the transistor D1 and stabilizer on the radiators, as well as shielding the entire circuit to reduce the radiated noise.


Hospital vs. Single-use
The traditional practice of negative pressure wound therapy is commonly found in the in-hospital use NPWT devices. Under these conditions, the devices are managed according to continuous or intermittent modes for various pressure levels. Patients need to stay in the hospital during treatment where they can rent or purchase traditional powered-NPWT devices.
Single-use NPWT Devices
NPWT has made tremendous advances with the introduction of single-use devices. With mobility inherent in design, patients can conduct NPWT at home. New upgraded versions without power supply and canisters offer many advantages, including:
New NPWT devices can create a negative pressure environment over wound sites through suction and manual compression without battery power. These devices are also less noisy and vibration levels experienced by patients are reduced.
With multi-layered dressings capable of absorbing exudate without additional canisters, new NPWT devices have the advantage of being lightweight.
Simplicity in operation and dressing change:
Set-up and operations are easy and intuitive for patients. Visual, audio and tactile alarms allow patients to monitor the negative pressure level over wounds and notify them of dressing changes. Moreover, the dressings have good absorption capability and can be directly used on wound beds without further trimming, decreasing the discomfort caused by dressing changes.
For patients who are mobile, new NPWT devices unleash the freedom of treatment at a time and location of their choosing. What’s more, patients can enjoy the convenience of taking light showers and participate in everyday activities for a better quality of life.
Hospital vs. Single-use NPWT Devices
Some have different modes to select from continuous to intermittent Range from -20 to -200mmHgSingle-use
Battery or non-powered
Depending on model, some are free of canisters
Dressing needs to be trimmed to fit the wound bedSingle-use
New dressing can be directly used on wound site


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laser has the advantages of being high in power and having many laser lines in the 9–11 µm infrared region. Thus, a CO2
laser photoacoustic spectrometer (PAS) can have a multi-component measurement capability for many gas compounds that have non-zero absorption coefficients at the laser lines, and therefore can be applied for measuring several volatile organic compounds (VOCs) in the human breath. We have developed a CO2
laser PAS system for detecting acetone in the human breath. Although acetone has small absorption coefficients at the CO2
laser lines, our PAS system was able to obtain strong photoacoustic (PA) signals at several CO2
laser lines, with the strongest one being at the 10P20 line. Since at the 10P20 line, ethylene and ammonia also have significant absorption coefficients, these two gases have to be included in a multi-component measurement with acetone. We obtained the lowest detection limit of our system for the ethylene, acetone, and ammonia are 6 ppbv, 11 ppbv, and 31 ppbv, respectively. We applied our PAS system to measure these three VOCs in the breath of three groups of subjects, i.e., patients with lung cancer disease, patients with other lung diseases, and healthy volunteers.
This is an open access article distributed under the Creative Commons Attribution License
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited


Tuesday, 11 January 2005
Characterization of AIRS temperature and water vapor measurement capability using correlative observations
The Atmospheric Infrared Sounder (AIRS) system on NASA’s Aqua spacecraft is an important new source of information about weather and climate processes. We use correlative observations to show that AIRS total water vapor estimates have no cloud-dependent biases. We also demonstrate that AIRS is meeting its fundamental measurement requirements of 20% absolute humidity uncertainty in 2 km layers, and 1 K temperature uncertainty in 1 km layers for infrared cloud fraction up to 70%. AIRS has provided over 300,000 globally distributed retrievals per day since September 2002, and has a five-year planned lifetime. Each retrieval includes profiles of temperature and water vapor, plus characteristics of clouds, the surface and minor gases. Higher information content retrievals –at infrared cloud fractions up to about 70%-- result from a combination of infrared and microwave measurements; lower information content retrievals are obtained from the microwave for higher cloud fractions. In this presentation we address several fundamental issues in the measurement of temperature and water vapor by AIRS: accuracy, precision, vertical resolution and biases as a function of cloud amount. We use two correlative data sources. First we compare AIRS total water vapor with that from the Advanced Microwave Sounding Radiometer for EOS (AMSR-E) instrument, also onboard the Aqua spacecraft. AMSR-E uses a mature methodology with a heritage including the operational Special Sensor Microwave Imager (SSM/I) instruments. AIRS and AMSR-E observations are collocated and simultaneous, providing a very large data set for comparison: about 200,000 over-ocean matches daily. We show small cloud-dependent biases between AIRS and AMSR-E total water vapor for several oceanic regions. Our second correlative data source is several hundred dedicated radiosondes launched during AIRS overpasses. Closely matched in space and time with AIRS retrievals, these sondes provide information about the vertical structure of temperature and water vapor. We present height-dependent AIRS-sonde differences at several locations around the globe, and show that AIRS is meeting its fundamental measurement requirements for temperature and water vapor profiles. We also show where AIRS exceeds it vertical resolution requirements. These results demonstrate that AIRS temperature and water vapor retrievals are suitable for the study of a wide variety of weather and climate phenomena.


DURING the past 25 years, Lawrence Livermore has become a world-renowned research center for designing, building, and utilizing high-peak-power and high-energy lasers. Starting with the 100-million-watt, two-beam Janus laser in 1974, we designed and built a series of laser systems, each providing five to ten times more irradiance (power per unit area) than its predecessor.|
Our series of increasingly more capable facilities now culminates in a revolutionary one-aperture laser, the Petawatt, with output power exceeding a quadrillion watts. Using the technique of chirped-pulse amplification, which enables us to produce very short (less than a trillionth of a second) energetic pulses on one arm of the ten-arm Nova laser, the Petawatt is able to exceed the total power of Nova by a factor of 10.
Even more impressive than its output power is the Petawatt's extraordinary brightness. Coupled with innovative focusing schemes, this brightness will enable the Petawatt to be focused to irradiances that produce an electric field exceeding by a factor of 100 the force that binds an electron to a proton in the hydrogen atom.
"Crossing the Petawatt Threshold," beginning on p. 4, describes the major technical and scientific advances that were required to make a petawatt laser a reality at Livermore. These advances in laser science and optical component fabrication have enabled revolutionary new concepts in laser science and machining as well as information display production technologies.
What's more, the enormous energy density of the Petawatt will push back the frontiers of knowledge about laser-matter interaction and expand our knowledge of matter under extreme conditions. For the first time in a laboratory setting, we will be exploring relativistic plasma physics and new sources of coherent and incoherent radiation at high photon energy.
Finally, the Petawatt will allow us to test a new pathway to laser fusion, called "fast ignition," that was developed at Lawrence Livermore early in this decade. As described in the article, the fast-ignition concept cleverly sidesteps the most difficult aspects of achieving fusion ignition with conventional inertial confinement fusion design.
The enormous opportunities created by the Petawatt will keep Lawrence Livermore in the forefront of high-power laser physics and high-energy-density physics for the foreseeable future.


When gas moves from a high-pressure area to a low-pressure area through a hole , it expands very rapidly and produces a turbulent flow, resulting in an audible "hissing" sound. The "hissing" sound is broadband acoustic sound, which ranges from the audible frequency range (20 Hz to 20 kHz) into the ultrasonic frequency range (16 kHz to 10 MHz).
The level of ultrasound produced by a gas leak is determined by three main factors (mainly 1 and 2):
- The pressure drop across the leak
- The physical size of the leak
- Gas specific properties such as: molecule weight and the specific heat ratio of the gas
For the turbulent flow to take place and produce ultrasound the pressure on one side of the leak has to be at least twice the pressure of the other side of the leak. Besides, if the hole is too big, the pressure drop across the hole will be too little, and no ultrasound will be produced.
The three factors above - mainly the pressure and the leak size - will decide whether enough ultrasound is generated to trigger an ultrasonic (acoustic) gas leak detector. The standard for these parameters is referred to as the leak rate - and this standard can be calculated by means of a mass flow formula.


Calibration Laboratory RAMS MALTA
This achievement places CALAB as the FIRST and ONLY Maltese Calibration Laboratory that offers Accredited calibration in Temperature,Humidity, Electrical and Pressure measurement. CALAB Accredited Calibration are for measurement ranges of 95°C to 550°C , 5% to 95% RH, 1 to 1000bar More detail can be found in the Scope of Accreditation issued by NAB MALTA, please click here
INTERNAL STANDARD CALIBRATION
of the internal standard in the sample or sample extract is compared to a similar . ratio derived for each calibration standard. Ref: SW846, 8000C, Section 11.4.3, Revision 3, March 2003
Calibration Standards For Sale
Sale price $4, Regular price $10, Sale About These Items For Sale QualiCal, LLC was an ISO 17025 accredited calibration facility, with many standards and equipment used for this process.
MicroCal™ Pressure Calibrator Setra Systems
The MicroCal automated pressure transducer calibrator is used as a stand alone calibration standard for differential and gauge pressure sensors found in critical environments. Setra partnered with NASA to develop the industry's quickest and most stable pressure control for low pressure range applications.
Reference Standards: Search Standards Restek
Our high quality air monitoring gas calibration standards are provided by Spectra/Linde and Airgas (formerly Scott/Air Liquide gas) — meeting lab requirements for two separate sources of calibration standards. Note: Actual cylinder pressure may vary due to loss from quality testing procedure.
Micrometer Calibration Standard Sets
Starrett 1 to 5 Inch Long, 5 Piece Micrometer Calibration Standard Set For Use with Outside Micrometer, Includes Case, 5 Inch Long Your Price: $ ea.
VALIDATE® ready to use kits are designed to assist in the documentation of linearity, calibration verification and verification of linear range required by many inspection agencies. VALIDATE® will also provide assistance when troubleshooting instrument systems, reagent problems and calibration anomalies. LGC Maine Standards is the brand
The Checking and Calibration of Torque Wrenches
1. The calibration must be carried out in controlled temperature and humidity conditions. Records must be kept of the temperature during the calibration. 2. The torque measuring instrument is called a calibration device in the standard. This device must have an uncertainty of measurement no greater than +/ 1% of reading.
The calibration services of the National Institute of Standards and Technology (NIST) are designed to help the makers and users of precision instruments achieve the highest possible levels of measurement quality and productivity.
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Testing & Calibration laboratories
Testing and calibration laboratory accreditation requires conformance to the international standard EN ISO/IEC 17025 which defines general requirements for the competence of testing and calibration laboratories. This standards establish both management and technical requirements.
STAREX calibration Micro Precision
STAREX Calibration Micro Precision provides calibration for all types of STAREX instruments, calibration test equipment sale and repair.
Electrical Calibration Equipment Fluke Calibration
Electrical calibration refers to the process of verifying the performance of, or adjusting, any instrument that measures or tests electrical parameters. This discipline is usually referred to as dc and low frequency electrical metrology. Principal parameters include voltage, current, resistance, inductance, capacitance, time and frequency.
International Standards Used In Calibration
International Standards Used In Calibration. ISO 9001 or ISO 17025: How to choose a calibration company As a calibration company we are sometimes asked which is better ISO 9001 or ISO 17025 certification. That really is the wrong question. Both of these International standards are excellent.
Load Cell calibration LCM Systems Ltd
Calibration . Calibration can be defined as a set of operations that compares the accuracy of a measuring instrument of any type (such as a load cell) against a recognised standard. The process of calibration may also include adjusting the measuring instrument to bring it in alignment with the standard.
Calibration Weights Scales and Scale Accessories
Hook Calibration Weights are suitable for testing light industrial weighing devices, and for routine calibration of scales or verification checks. They can be used with slotted weights.
Professional Calibration Services Team UsCalibration
Your calibration is done correctly, your equipment is handled properly and safely returned to you. Calibrations comply with many quality standards including ISO 9001, AS9100, NADCAP, ISO 13485, ISO/IEC 17025, ANSI/NCSL Z540, AMS2750, FDA, & Boeing.