Calorimetric Output Research Articles

Upgrade of ATLAS hadronic Tile Calorimeter for the High-Luminosity LHC

The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment, with steel as absorber and plastic scintillators as active medium. The High-Luminosity phase of LHC, delivering an instantaneous luminosity up to 7.5×1034 cm−2 s−1, is expected to begin in 2029. TileCal will require new electronics to meet the requirements of a 1 MHz trigger (calorimeter output rate), higher ambient radiation, and to ensure better performance under high pile-up conditions. Both the on- and off-detector TileCal electronics will be replaced during the shutdown of 2026–2028. The TileCal upgrade program has included extensive R&D and test beam studies. A Demonstrator module with reverse compatibility with the existing system was inserted in ATLAS in August 2019 for testing in actual detector conditions. The ongoing developments for on- and off-detector systems, together with expected performance characteristics and recent results of test-beam campaigns with the electronics prototypes will be discussed.

Fast simulation of a high granularity calorimeter by generative adversarial networks

We present the 3DGAN for the simulation of a future high granularity calorimeter output as three-dimensional images. We prove the efficacy of Generative Adversarial Networks (GANs) for generating scientific data while retaining a high level of accuracy for diverse metrics across a large range of input variables. We demonstrate a successful application of the transfer learning concept: we train the network to simulate showers for electrons from a reduced range of primary energies, we then train further for a five times larger range (the model could not train for the larger range directly). The same concept is extended to generate showers for other particles depositing most of their energies in electromagnetic interactions (photons and neutral pions). In addition, the generation of charged pion showers is also explored, a more accurate effort would require additional data from other detectors not included in the scope of the current work. Our further contribution is a demonstration of using GAN-generated data for a practical application. We train a third-party network using GAN-generated data and prove that the response is similar to a network trained with data from the Monte Carlo simulation. The showers generated by GAN present accuracy within 10% of Monte Carlo for a diverse range of physics features, with three orders of magnitude speedup. The speedup for both the training and inference can be further enhanced by distributed training.

Nursery greenhouses heated with geothermal energy – A case study from Rotorua New Zealand.

The InfraCore nursery in Rotorua is a unique case of greenhouse heated with geothermal energy. The nursery only runs at full capacity during the colder six months of the year, when the geothermal heating system is operational. However, a large expansion project to grow gourmet vegetables and greens would require heating year-round. The nursery and greenhouses infrastructure and its direct heat use technology are characterised in detail. Wellbore static and flowing conditions were determined using PTS and calorimeter output tests and wellbore simulation. The existing production well has enough capacity to provide thermal energy for both developments, providing that the well is kept clean of calcite scaling.

The Machine Learning landscape of top taggers

Based on the established task of identifying boosted, hadronically decaying top quarks, we compare a wide range of modern machine learning approaches. Unlike most established methods they rely on low-level input, for instance calorimeter output. While their network architectures are vastly different, their performance is comparatively similar. In general, we find that these new approaches are extremely powerful and great fun.

Combustion of sub-standard liquid hydrocarbons dispersed by a superheated steam jet

This paper by the example of spent automobile transmission oil investigates the combustion of sub-standard liquid hydrocarbons in a straight-flow burner, implementing a promising method of liquid fuel dispersion by a superheated steam jet. The aim of the work is to study the influence of regime parameters on the thermal and environmental characteristics of the combustion process. Gas composition of combustion and heat release products was measured. A flow calorimeter was used to measure heat release. The measurement of the amount of generated heat was based on determining the coolant temperature difference at the inlet and outlet as well as the flow rate of the coolant and fuel under stationary experimental conditions. TESTO 350 gas analyzer was used to control the composition of gaseous combustion products. Sampling of reaction products cooled to room temperature was carried out at the calorimeter output. Dependences of specific heat release on steam and fuel flow rates have been obtained. The regimes with low CO content in the combustion products have been found.

A new tool for an old job: Using fixed cell scanning calorimetry to investigate dilute aqueous solutions

The development of fixed twin cell temperature scanning calorimeters has enabled the more efficient determination of heat capacities of dilute aqueous solutions with a precision comparable to that of the Picker flow heat capacity calorimeters developed nearly 40 years ago. Experiments require less than 0.5 cm 3 of solution, and results can be obtained routinely over the temperature range (278 to 395) K at pressures up to a few bars. Multiple scanning of samples by both increasing and decreasing temperature allows assessment of instrument drift, solute stability, and reproducibility of results. Chemical calibration is essential to take full advantage of the precision and sensitivity of the calorimeters. The calorimetric output is a direct measure of the difference in heat capacity per unit volume of a solution and of a reference liquid, usually water. Thus, densities of the solution and reference liquid are needed to transform the results into heat capacities per unit mass of solution. Examples of solutes that have been investigated include a variety of inorganic and organic compounds that dissolve to give simple ionic or neutral species, or that produce complexes or species that exist in equilibrium distributions that can change as the temperature is scanned. Appropriate selection of the results from experiments on combinations of solutes allows calculation of standard state (zero concentration) thermodynamic quantities for chemical processes and reactions over the ranges of temperature scanned at the solution compositions investigated. Results for a few specific systems are presented and discussed for some representative classes of solutes that have been investigated in our laboratory since 1998.

Recent Developments for the Analysis of Data Obtained from Isothermal Calorimetry

Isothermal calorimetry is rapidly becoming an indispensable tool for the quantitative determination of a variety of kinetic and thermodynamic parameters for a wide range of systems. In particular calorimetry is finding increased application to the investigation of stability and incompatibility of pharmaceutical materials. In order to draw meaningful conclusions and to predict behaviour in related systems it is necessary to have the means to calculate accurately parameters such as the rate constant and enthalpy. To this end several groups have been developing equations which describe calorimetric output in these terms. This paper will briefly outline some of these equations and discuss some of the limitations that currently exist in their application. A particular emphasis is placed on the recent developments relating to the application of these equations to flow calorimetric data. The main application of these equations is usually found in the pharmaceutical industry. Pharmaceutical formulations are usually extremely complex mixtures consisting of many different excipients as well as the active drug. Because of these large numbers of ingredients it is often observed that multiple chemical and physical process occur over the lifetime of the study. This complexity is then reflected in the calorimetric data rendering the application of the simple equations useless. Dealing with this complexity is a major issue amongst the calorimetric community and some of the recent advances in this field are also discussed.

Initial hydration of cementitious systems using a simple isothermal calorimeter and dynamic correction

A simple isothermal calorimeter ideal to study hydration of cementitious systems is described together with an ampoule design to allow addition of water and mixing with the ampoule inside the calorimeter. An overview of dynamic corrections is given, and the utilisation of the different dynamic corrections on the calorimeter output is discussed. Correction of data on b-hemihydrate hydration to form gypsum has shown good kinetic agreement with data from synchrotron X-ray diffraction.

Calorimetric Analysis of Vesicular Systems

A number of studies of micellar aggregation in aqueous solutions of ethylene oxide-propylene oxide block copolymers — using high sensitivity differential scanning calorimetry (HSDSC) — are reviewed. The review attempts to show how the calorimetric output can be analysed, using a model fitting procedure, to obtain estimates for various thermodynamic parameters, which characterise the micellization event, as observed by HSDSC. These important parameters include:

Thermogravimetry in the analysis of results of a calorimetric experiment

A method based on a refined measurement equation is proposed for enhancing the accuracy of measurements of the specific heat of solids. The equation uses calorimetric and gravimetric output signals along with analytical representation of the output and baseline signals.

Conduction Calorimeters Heat Transmission Systems with Uncertainties

A critical reading of early papers on heat flux or conduction calorimetry (1920-1965) reveals the original kinetic aims of the developed instrumentation and the progressive appearance of the intrinsic difficulties. An analysis of current publications demonstrates biased application/results relating to equivalent problems. Modelling of the systems by the RC analogy of heat transfer equations establishes the problems connected with the structure of the apparatus and also the experimental conditions to be fulfilled. Analysis of the equations highlights several possibilities that are used in part today. For instance, the reduction of noise and drift on the calorimeter output by a software approach and the conditions to be attained with crucibles for increased accuracy.

Thermodynamic Model Fitting of the Calorimetric Output Obtained for Aqueous Solutions of Oxyethylene− Oxypropylene−Oxyethylene Triblock Copolymers

A high-sensitivity differential scanning calorimetry (HSDSC) study of aggregation transitions in dilute aqueous solutions of oxyethylene−oxypropylene−oxyethylene (EO−PO−EO) triblock copolymers (poloxamers) is reported. The data have been analyzed using a previously described thermodynamic model (Armstrong, J. K.; et al. J. Chem. Res. 1994, 364) based upon a mass action description of aggregation which has been further elaborated to include the effect of changes in the heat capacity of the initial and final states. As a consequence the model incorporates the underlying changes in the heat capacity of the system, thus obviating the need for baseline fitting and as such provides a useful mechanism for the analysis of the data. Model-fitting results are presented for aqueous solutions of various concentrations of the poloxamers P237 (EO62PO39EO62) and P333 (EO19PO56EO19). In addition model-derived results are presented for a number of other poloxamer solutions. The thermodynamic data obtained are further used...

Effect of Cosolvents and Cosolutes upon Aggregation Transitions in Aqueous Solutions of the Poloxamer F87 (Poloxamer P237): A High Sensitivity Differential Scanning Calorimetry Study

The effects of a number of different cosolvents and cosolutes upon the micellization of the oxyethylene/oxypropylene/oxyethylene block copolymer F87 (P237; 70% oxyethylene and 30% oxypropylene) have been investigated using high-sensitivity differential scanning calorimetry (HSDSC). The calorimetric output has been analyzed using a model fitting procedure to obtain estimates for various thermodynamic parameters which characterize the micellization event as observed by HSDSC. These important parameters include T1/2, the temperature at which the micellization process is half-completed, ΔHcal, the calorimetric enthalpy for the process which is measured by integration of the calorimetric output; ΔHvH, the van't Hoff enthalpy; and n the aggregation number. From this data it has been possible to measure critical micelle concentrations (cmcs). The experimental investigations reveal that methanol, ethanol, urea, and formamide prevent the onset of micellization, while butanol and hydrazine favor micelle formation. ...

Heat capacity measurement by calibration with dynamic correction of the calorimetric output signal of a thermopile heat conduction calorimeter

This paper deals with a new quasi-isothermal method for the measurement of heat capacities of good thermal conductors in an LKB 2277 heat flow microcalorimeter TAM (Thermal Activity Monitor), applying a calibration technique with dynamic correction for the calorimetric output signal. The specific heat capacities of materials with good thermal conductivities, e.g. metals, can be determined with an uncertainty of less than 4%. This new method provides a fast and simple procedure for the measurement of the specific heat capacity in less than 30 min. With a quasi-isothermal method, no heating or cooling of the calorimetric unit is needed. The temperature of the thermostat represents directly the test temperature.

Microcalorimetric study of the system adenosine-5′-triphosphate—sodium, potassium adenosine-5′-triphosphatase: Part 1. Determination of the catalytic activity of Na +, K + ATPase

The catalytic activity of adenosine-5′-triphosphatase (5′-ATPase), activated by Na + and K + ions in the presence of Mg 2+ ions, was determined by a direct method using batch microcalorimetry. The enzymatic hydrolysis of 5′-ATP in Tris—HCl buffer was used without any auxiliary reaction. The rate of heat change associated with the enzymatic reaction, which could be related to the enzymatic activity of the Na +, K + ATPase, gave rise to a linear correlation between the calorimetric output and the enzymatic activity. The method was successfully applied to real matrices, in particular to membranes of human erythrocytes, without particular pretreatment.

In vitro dissolution testing of oral controlled release preparations in the presence of artificial foodstuffs. II. Probing drug/food interactions using microcalorimetry

The dissolution of tetracycline hydrochloride from a commercial sustained release product (Organon-Tetrabid) and from a dispersion of the drug in a semi-solid matrix was studied. Two techniques were used to follow dissolution, these were the USP paddle method (with UV analysis) and microcalorimetry. The influence of calcium on the dissolution rate was studied using the USP method, and was found to have no effect. Dissolution experiments were undertaken in the calorimeter using hydrochloric acid alone or with the addition of: (i) calcium; (ii) milk; (iii) Ensure; and (iv) Intralipid. It was possible to observe the known interaction between tetracycline and calcium, milk and Ensure during the dissolution process in the microcalorimeter. The calorimetric output during dissolution (a composite response for dissolution of the drug and base, and any measurable interaction that occurs) of the products in acid and the non-interacting Intralipid, being distinctly different to the output obtained during the dissolution in interacting fluids. This was equally true for both products. The kinetics describing the release from the semi-solid matrix show that an apparent zero-order process occurs for about 150 min followed by an apparent first-order process. The data obtained from the microcalorimeter showed considerable differences in the first-order release process, depending upon the nature of the dissolution fluid; those with the highest content of lipid giving different results to the more aqueous fluids. With careful selection of experiments microcalorimetry is a useful technique for the in vitro study of drug/food interactions and the influence of food on drug release profiles.

Aerobic Metabolism and Physiological Responses of Aquatic Oligochaetes to Environmental Anoxia: Heat Dissipation, Oxygen Consumption, Feeding, and Defecation

Anoxic heat dissipation of Lumbriculus variegatus, as measured by direct calorimetry, is reduced by up to 85% relative to aerobic rates. The decrease of anoxic heat dissipation and the diminution of activity peaks in the calorimetric output coincide with the disappearance of peristaltic movements under anoxia. A transfer from aerobic conditions with food to anoxia without food results in cessation of defecation when the gut is half emptied, whereas the gut is completely emptied under aerobic conditions within 6 and 8-10 h at 20 and 11 C, respectively. The aerobic retention time of the food is independent of worm length (10-50 mm). After aerobic feeding the gut content is higher than after anoxic feeding at 6 C. On return to aerobic conditions, heat dissipation increases immediately, whereas defecation is resumed only after a lag of 2 h. An anoxic component to the aerobic heat dissipation becomes apparent in relation to simultaneous respirometric measurements when feces accumulate in the calorimetric chamb...

A noise filter for calorimeter signals

This article describes a general method for filtering noise from thermograms which uses the previously determined autocorrelation function of the noise produced by the calorimeter apparatus together with an estimate of the second derivative of the signal being processed. The method is applied to a standard Calvet microcalorimeter, the autocorrelation function of whose noise is shown, and the variable number of points required by the filter in this case is plotted against a convenient function of the second derivative of the signal. Comparison of deconvolved calorimeter output signals with and without previous filtering shows the filter to function as desired.

Human gradient-layer calorimeter: development of an accurate and practical instrument for clinical studies.

A whole body gradient-layer calorimeter was designed for thermophysiologic studies in hospitalized patients. The instrument was assembled in a room adjoining a metabolic ward. The patient lies recumbent on a stretcher which is wheeled into the calorimeter on tracks. Once inside, the patient's head extends through one wall into a clear plastic canopy. The canopy is partially open on one side and is the entry point for fresh air into this open-circuit system. Heat flux transducers in the calorimeter walls, a thermopile in the exit air stream, and a platemeter in conjunction with wet and dry bulb thermometers allow measurement of total, wet, and dry heat losses from the subject. All calorimeter output signals are routed to a microcomputer system which processes the data and provides real-time output of results. A mannequin heat source is used to calibrate the gradient layer. Testing with a variety of wet/dry heat sources indicate total, wet, and dry heat measurements are accurate to within 2-3%. A typical study of resting energy expenditure requires 1 hr, and protocols of up to 6 hr are well tolerated. The calorimeter has proven to be reliable, accurate, and easy to operate. These qualities, combined with good patient tolerance, make it ideal for metabolic studies.

Thermogenese: Application des filtrages electronique et numerique inverses en calorimetre a conduction

The results of the application of the numerical and electronic inverse filtering to the same calorimetric output are presented. These two techniques, used to reduce the inertia of conduction calorimeters, give very similar results.