Calorimetric Device Research Articles

Calorimetric flow-injection determination of glutathione with enzyme-thermistor detector

Glutathione sulfhydryl oxidase and catalase are separately immobilized onto oxirane-acrylic beads (Eupergit-C). Both types of beads are double-layered into a small polymer column. The flow-injection analysis system for glutathione is assembled with the column and a calorimetric device for enzymatically generated heat. The calibration graph for glutathione is linear from 0.5 to 10 mM for 0.2 ml samples. The assay takes less than 6 min. The relative standard deviation for 5.0 mM glutathione is 1.2% ( n = 5).

Graphical Concepts for the Representation of Events in High Energy Physics

Different methods to graphically represent points and tracks of events, measured with the ALEPH-detector at LEP, are discussed. Special emphasis is put on projections, that are adapted to the cylindrical geometry of the detector, to the track geometry of charged particles moving in a homogeneous magnetic field and to the specific event topologies, encountered in Z0 physics. A new concept, the so-called “V-plot”, is introduced, which incorporates the full three dimensional information of spatial points in a single picture. It is ideally suited for the study of more complicated event topologies, such as e.g. decays of particles within jets, and of the correlation between information from tracking and calorimetric devices. In addition, we propose ways of combining histograms and projections in a single picture. We describe methods of employing colour schemes to facilitate recognition of correlations between hits, tracks and/or subdetectors in different representations.

The limited streamer tubes of the SLD

Abstract A large hadron calorimeter and muon tracking device using plastic streamer tubes has been constructed in the iron flux-return structure for the SLD detector at SLAC. Various studies of the operating characteristics of the streamer tubes of this system are presented. Emphasis is placed on the tracking capabilities of the device and on the optimization of the high voltage and readout electronics.

A calorimetric device for the investigation of transformations in solids in the temperature range 100 K–500 K

This paper introduces a calorimetric device that can be used to observe reactions in the temperature range 100 K–500 K. The principal part of the apparatus is an improved version of a commercial differential heat flux calorimeter. Cooling is effected by a low-temperature cryostat for liquid nitrogen into which the calorimeter is fitted. It can be heated up linearly with time at different rates using a controllable heater. These properties qualify it as a member of the class of D ifferential- T emperature- S canning- C alorimeters (DTSC). The calorimeter has hitherto been applied to the investigation of the annealing effects in high-purity aluminium after low-temperature deformation /1,2/. A description shall be given here of the device and its particular characteristics. To demonstrate the efficiency of the calorimetric device reaction curves are shown which were obtained for different metals after plastic deformation at low temperatures (deformation by torsion at 77 K).

On the calculation of the energy loss of muons in sampling calorimeters

A Monte Carlo (MC) technique has been used to investigate the energy loss of muons in sampling calorimetric devices. Two existing MC codes have been combined to calculate the muon transport with δ-electron-, bremsstrahlungs- and pair production (MUDEX) and the transport of these secondaries (EGS). The results show that with the help of such a detailed MC calculation, a precise calibration of sampling calorimeters is possible with muons.

Plastic fibers in high energy physics

Plastic scintillating fibers open up new possibilities in the design of detectors at future accelerators. We present the construction and testing of prototypes for calorimeter and tracking devices.

Hydrogenation enthalpimetry—I Microcomputer-assisted calibration and data-acquisition

A calorimetric device is described which permits enthalpimetric determination of unsaturated hydrocarbons through the enthalpy change for their catalytic hydrogenation. Samples with weights from < 1 to about 20 mg can be analysed with a mean error of about 2%. The method makes extensive use of digital electronics and is well suited to routine automated determination of unsaturation. The principal drawback is lack of specificity.

Is gradientless solid state calorimetry possible?

Abstract Proceeding from the condition Bi → O which, according to the general theory of heat conduction is a necessary condition for a uniform temperature distribution in a heated (cooled) body, the sufficient conditions for bringing about a gradientless solid state system (construction principles thereof) have been defined and a calorimetric device based thereupon has been elaborated; its conformity to the gradientless theory of differential thermal analysis has been established.

Determination of Oxalate with Immobilized Oxalate Oxidase in an Enzyme Thermistor

Abstract This paper describes a rapid enzymic procedure, based on calorimetry, for specific determination of oxalic acid. Oxalate is oxidized by immobilized oxalate oxidase to hydrogen peroxide and carbon dioxide. The heat generated by this reaction is measured in a calorimetric device, the enzyme thermistor. Oxalate concentrations as low as 0.02 mM can be determined. Also described is purification and immobilization of the enzyme, as well as the effect of some of its inhibitors. The urinary oxalate content of 16 persons was determined using the enzyme thermistor. For samples containing a very low concentration of oxalate (less than 0.2 mM) an extraction step with tributylphosphate can be introduced to purify and concentrate the oxalate. The oxalate content in different kinds of food was also determined.

A calibration system for calorimetric mass flow devices

Describes a simple gas flows calibration system which consists of the combination of a secondary standard mass flowmeter and a primary standard volume displacement method. The system has been built for the routine calibration of calorimetric mass flow devices as well as for changing their flow range. Reviews the literature on thermal mass flow instruments and discuss the operations of a commercial shunt type mass flow controller. In the appendix the authors derive the pertinent equations for the different calorimetric mass flow devices in detail. They review a few of the more common calibration methods used in industry and give the corresponding equation and flow corrections required.

Modern Methods of Thermal Analysis

PREFACE The position and importance of thermal analysis among methods of material research and structure elucidation is well shown by the review which appeared in Research and Development Journal.1 According to the review, about 42% of the laboratories surveyed are using, or expect to be using in the near future, thermogravimetric (TG), differential thermal analysis (DTA), or differential scanning calorimetric (DSC) devices. It is also characteristic that about 1 to 2% of the papers appearing yearly on analytical chemistry deal with the problems of thermal analysis.2,3 It is clearly shown by these data that thermal methods of analysis cannot compete with electroanalytical, spectroscopic, and chromatographic methods with respect to practical applications. Nevertheless, they play an important part in material research. If used and interpreted properly, methods of thermal analysis provide unique information in both theoretical and practical respects about the thermal behavior of samples.

Differential calorimeter for measurement of absorbed energy in laser-produced plasmas

Accurate estimates of the amount of optical energy absorbed by a target are an important diagnostic of laser-induced fusion experiments. Measurements of the total energy blown off of a target in the form of charged particles is one method of evaluating the percentage of optical absorption. We have developed a special calorimetric device that is suitable for the measurements of the total flux of both charged particles and x rays. These devices provide high sensitivity to ions and x rays while maintaining good discrimination against scattered light.

Closed evaporative cooling of rotating electrical machines

Elements of a theory for centrifugo-axial heat pipes are described along with a calorimetric device for their experimental investigation. Experimental data presented confirms the fundamental correctness of the initial theoretical hypotheses.

He3(He3,2p)He4Total Cross-Section Measurements Below the Coulomb Barrier

Measurements of total cross sections for $^{3}\mathrm{He}(^{3}\mathrm{He},2p)^{4}\mathrm{He}$ have been made for center-of-momentum energies between 80 keV and 1.1 MeV. A continuously recirculating differentially pumped gas target system was employed to minimize uncertainties in energy loss and straggling. A calorimetric device was used to integrate the beam current within the target gas. Proton angular distributions were measured at seven energies. The measured cross-section factor, $S(E)$, was fitted to a linear function of energy for ${E}_{\mathrm{c}.\mathrm{m}.}&lt;500$ keV: $S({E}_{\mathrm{c}.\mathrm{m}.})={S}_{0}+{{S}_{0}}^{\ensuremath{'}}{E}_{\mathrm{c}.\mathrm{m}.}$, where ${S}_{0}=({5.0}_{\ensuremath{-}0.4}^{+0.6})$ MeVb and ${{S}_{0}}^{\ensuremath{'}}=(\ensuremath{-}1.8\ifmmode\pm\else\textpm\fi{}0.5)$ b. The formula $S({E}_{\mathrm{c}.\mathrm{m}.})={S}_{0}+{{S}_{0}}^{\ensuremath{'}}{E}_{\mathrm{c}.\mathrm{m}.}+\frac{1}{2}{{S}_{0}}^{\ensuremath{'}\ensuremath{'}}{E}_{\mathrm{c}.\mathrm{m}.}^{2}$, with ${S}_{0}=5.2$ MeVb, ${{S}_{0}}^{\ensuremath{'}}=\ensuremath{-}2.8$ b, and ${{S}_{0}}^{\ensuremath{'}\ensuremath{'}}=2.4$ b Me${\mathrm{V}}^{\ensuremath{-}1}$ gives a good representation of $S(E)$ over the entire range of energies studied here.

The use of the flat plate method to investigate the thermophysical properties of highly efficient heat insulation at low temperatures

This paper describes the design and technical features of a calorimetric device for the investigation of the thermophysical properties of highly efficient insulation in the temperature range 4.2°–373° K.

Power and energy measuring techniques for solid state lasers

Methods of measuring the energy and power of a Q-switched neodymium glass laser in the range 10 −3−1 J and 10 4–10 8 W are described. Calorimetric devices using discs, cones and wire were constructed for energy measurements and are discussed with respect to construction, materials and calibration. Power measuring systems using vacuum and silicon photodiodes are also described. Of the five detectors investigated the wire calorimeter and silicon photodiode systems were developed and an experiment in which the two detectors were used simultaneously to measure the laser output showed good agreement between the results.

Physiology of the circulation in human limbs in health and disease

This is a fairly extensive monograph of a limited but important segment of hemodynamics—that is, the anatomic and physiologic basis for the response of the vessels in the various tissues of the limb in the direction of vasodilatation or vasoconstriction. The book reflects the timing and locale of the author's researches—namely, Great Britain, in the time when instruments such as the plethysmograph and various calorimetric devices furnished the essential part of the data. The experiments reflect the painstaking, simple approach with these apparatus, from which some rather refined deductions are drawn. Readers of the book will immediately think of the experiments reported by Lewis and by Pickering. While this book thus summarizes a large body of work done on the blood supply of the limbs, it fails to record work done upon the circulation as a whole and work done with more refined instrumentation, such as direct blood vessel flow

Isothermic irradiation of nonfissionable materials in the RFT reactor by means of calorimetric devices

The present article is concerned with the generation of heat due to the absorption of the energy of γ-radiation from the reactor spectrum in nonfissionable materials when they are irradiated in the reactor core. The calculated dependence of the γ-radiation energy mass absorption coefficient on the atomic number for the RFT spectrum was plotted [1], A steady-state method for determining the amount of heatq generated per unit mass of nonfissionable materials when they are irradiated in heat-producing assemblages, which has been developed in using RFT, is described here. The obtained values for aluminum, Steel 30, tin, and lead vary from 2.2 to 3,7 w/g for cylindrical specimens with diameters equal to 13.5 and 10 mm and a 10-Mw reactor power level. The dependence ofq on the distance to the reactor central line within the core zone has a cosinusoidal character. A method which is used for isothermic irradiation of specimens and containers at temperatures above the coolant temperature is described.

Isothermal irradiation of non-fissile materials in a reactor by means of calorimetric devices

Isothermal irradiation of non-fissile materials in a reactor by means of calorimetric devices