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Kleiber's definitions of what constitutes direct and indirect calorimetry are accepted as the beginning of a commentary on the advantages and disadvantages of direct and indirect calorimetry in which calorimetry is divided into a ...
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Kleiber's definitions of what constitutes direct and indirect calorimetry are accepted as the beginning of a commentary on the advantages and disadvantages of direct and indirect calorimetry in which calorimetry is divided into a number of categories based on the kind of calorimetric measurement. For non-reaction calorimetry such as entropy determinations and differential scanning calorimetry, the only means of measurement is by direct calorimetry. For reaction calorimetry, a preference of direct over indirect calorimetry depends on the accuracy needed and the ability of the experimenter to define the system. The data necessary to correct the observed heat loss in direct calorimetry are often all that are needed to make an indirect calculation of the true heat loss. In general, because they are convenient and inexpensive to use, indirect calorimetric methods are preferable to direct methods. However, when possible, one method can be used to verify the results of the other. [References: 70]
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The Particle Flow (PFlow) approach to calorimetry promises to deliver unprecedented jet energy resolution for experiments at future high energy colliders such as the proposed International Linear Collider (ILC). This paper describ...
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The Particle Flow (PFlow) approach to calorimetry promises to deliver unprecedented jet energy resolution for experiments at future high energy colliders such as the proposed International Linear Collider (ILC). This paper describes the PandoraPFA particle flow algorithm which is then used to perform the first systematic study of the potential of high granularity PFlow calorimetry. For simulated events in the ILD detector concept, a jet energy resolution of σ_E/E approx< 3.8% is achieved for 40-400 GeV jets. This result, which demonstrates that high granularity PFlow calorimetry can meet the challenging ILC jet energy resolution goals, does not depend strongly on the details of the Monte Carlo modelling of hadronic showers. The PandoraPFA algorithm is also used to investigate the general features of a collider detector optimised for high granularity PFlow calorimetry. Finally, a first study of the potential of high granularity PFlow calorimetry at a multi-TeV lepton collider, such as CLIC, is presented.
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Periodic heating has been applied more than a century ago to study thermophysical properties of materials. The measurement of heat capacity using a.c. calorimetry was first performed by Corbino in 1910. In connection with the tech...
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Periodic heating has been applied more than a century ago to study thermophysical properties of materials. The measurement of heat capacity using a.c. calorimetry was first performed by Corbino in 1910. In connection with the technological development and the progress in science and technology, new and sophisticated apparatus have been constructed in an a.c. calorimetric heat capacity measurements. In this measurement, the noise level of a.c. temperature can be reduced markedly as opposed to the other nonperiodic methods and, therefore, high precision determination can be attained. Furthermore, not only the amplitude but also the phase in a.c. temperature is a useful parameter in constructing much advanced apparatus. (C) 1997 Elsevier Science B.V. [References: 24]
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A calorimetric sensor for medical application has been developed to measure surface and localize heat dissipations of human body. The instrument evaluates the heat flux transmitted by conduction, through a thermopile, between the ...
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A calorimetric sensor for medical application has been developed to measure surface and localize heat dissipations of human body. The instrument evaluates the heat flux transmitted by conduction, through a thermopile, between the human body surface and a programmed thermostat at a set temperature. In this work, a model with twelve transfer functions describing the operation of the sensor is exposed. This model relates the inputs to outputs of the system. Sensitivities, poles and zeros of each of the transfer functions are obtained with two independent experimental measurements and a numerical optimization method based on the adjustment of the experimental output curves with the ones calculated by the model. The model simulates the operation of the sensor, determines its operating limits and assesses the flow of heat between human skin and the thermostat sensor. The proposed method is applicable to any non-differential calorimeter.
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Hadron calorimetry has been a rapidly developing field in the past few decades. Perhaps not too far in the future, a realistic calorimeter will be capable of measuring the energies of all the fundamental particles with ~ 1% precis...
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Hadron calorimetry has been a rapidly developing field in the past few decades. Perhaps not too far in the future, a realistic calorimeter will be capable of measuring the energies of all the fundamental particles with ~ 1% precision. Currently, calorimeters with unprecedented complexity attest to the knowledge and experience that have been accumulated in high energy physics. In this review, we touch on fundamental concepts and explain new developments that we expect to be important in the future. In addition to describing applications in accelerator-based high energy physics, we briefly mention the use of hadron calorimeters in other fields.
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If the scintillator response to a hadronic shower in a semi-infinite uniform calorimeter structure is S relative to the electronic response, then S/E = [f_(em) + (1-f_(em))(h/e)], where E is the incident hadron energy, f_(em) is t...
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If the scintillator response to a hadronic shower in a semi-infinite uniform calorimeter structure is S relative to the electronic response, then S/E = [f_(em) + (1-f_(em))(h/e)], where E is the incident hadron energy, f_(em) is the electronic shower fraction, and h/e is the hadron/electron response ratio. If there is also a simultaneous readout with a different h/e, say a Cherenkov signal C, then a linear combination of the two signals provides an estimator of that is proportional to the incident energy and whose distribution is nearly Gaussian-even though the S and C distributions are nonlinear in E, wide, and skewed. Since an estimator of f_(em) is also obtained, it is no longer a stochastic variable. Much of the remaining resolution variance is due to sampling fluctuations. These can be avoided in a homogeneous calorimeter. The energy resolution depends upon the contrast in h/e between the two channels, h/e is small in the Cherenkov channel. Mechanisms that increase h/e in sampling calorimeters with organic scintillator readout are not available in a homogeneous inorganic scintillator calorimeter. The h/e contrast is very likely too small to provide the needed energy resolution.
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The accuracy claimed for calorimetric measurements should be given at a certain confidence level. This paper describes how the standard uncertainty of isobaric enthalpy increment measurements from a new cryogenic flow calorimeter ...
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The accuracy claimed for calorimetric measurements should be given at a certain confidence level. This paper describes how the standard uncertainty of isobaric enthalpy increment measurements from a new cryogenic flow calorimeter is derived. The new calorimeter has several features that reduce the heat leakage better than previous designs. The temperature and pressure ranges covered by-the calorimeter are 133-335 K and 0.17-14 MPa. The enthalpy increment measurements have an average standard uncertainty of 0.10 kJ kg(-1) or 0.25% of the enthalpy increment. [References: 6]
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Biotic degradation techniques are gaining importance in decontaminating soils and waste water from organic pollutants. One class of organic pollutants of much interest are polyaromatic hydrocarbons (PAH), ubiquitous substances som...
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Biotic degradation techniques are gaining importance in decontaminating soils and waste water from organic pollutants. One class of organic pollutants of much interest are polyaromatic hydrocarbons (PAH), ubiquitous substances some of which show a high carcinogenic and mutagenic potential and acute toxicity. Although they usually possess a high thermodynamic stability they can be degraded by microorganisms. In our investigations of PAH degradation we used naphthalene as a model substance because of its high solubility. The degradation of naphthalene at 25 degrees C in liquid culture by Pseudomonas sp. strain KR3 was observed with a Thermometric microcalorimeter equipped with a flow cell. Bacterial cultures from a fermenter were pumped through this measuring cell via tubing. Parallel to the microcalorimetric investigations the amount of degraded naphthalene and the generation of metabolites were observed by HPLC analysis, and biomass production and oxygen consumption were measured. On degrading naphthalene, Pseudomonas sp. strain KR3 generated various metabolites at the same time. Only some of the metabolites had their maximum concentration synchronous to the maximum heat flow rate. Anabolic processes were delayed compared to the consumption of the substrate. A good correlation between calorimetric results and oxygen consumption was found. A relationship between a strong decrease in heat production after the main heat flow rate peak and inhibition of metabolic processes by lack of oxygen could be excluded. Decrease in the heat flow rate is assumed to be due to lowered gas exchange in the calorimeter tubes, i.e. the inhibited degassing of carbon dioxide. Calculation of an envelope for the heat flow rate is useful to improve experimental results. [References: 10]
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A new evaluation method for modulated temperature-DSC measurements based on linear response theory is presented. This yields a complex heat capacity with a real part (storage heat capacity) and an imaginary part (loss heat capacit...
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A new evaluation method for modulated temperature-DSC measurements based on linear response theory is presented. This yields a complex heat capacity with a real part (storage heat capacity) and an imaginary part (loss heat capacity). This approach makes irreversible (time dependent) thermal events amenable to quantitative and theoretically founded discussion. This is shown by theoretical analysis and demonstrated experimentally using the glass transition as an example. [References: 36]
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Under terrestrial conditions, the temperature behaviour of a sample in levitation may be different from that observed in microgravity. Here we present the temporal evolution of the polar and equatorial temperatures of a levitating...
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Under terrestrial conditions, the temperature behaviour of a sample in levitation may be different from that observed in microgravity. Here we present the temporal evolution of the polar and equatorial temperatures of a levitating charge of Ni, revealed numerically and experimentally for different AC current modulations. It is demonstrated that the motion of the sample during the AC current modulation should be taken into account.
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