Thermometric Method Research Articles

The Impact of Risk on Preference Values: Implications for Evaluations of Postmenopausal Osteoporosis Therapy

Objective The objective was to assess the impact of different levels of risk of disease on a woman's preferences for health states. Women were provided with health scenarios incorporating different levels of lifetime risks for breast cancer, hip fracture, and coronary heart disease (CHD). In this way, we were able to determine the incremental effect of changes in risks of each disease on preference values. Methods and Data Preference values and utility scores were obtained for six health scenarios by both the feeling thermometer (FT) and standard gamble (SG) methods. Scenarios presented the different lifetime risks of CHD, breast cancer, and hip fracture associated with and not associated with long-term use of hormone replacement therapy (HRT) and raloxifene. Risks of breast cancer were based on perceived risks and population risks. The sample population consisted of 40 healthy female volunteers aged between 45 and 65 years randomly selected from the Ottawa-Carleton district. Results Based on their perceived risk of breast cancer, the women had higher value scores for the raloxifene risk profile than for both HRT ( p = .002) and no therapy ( p = .003), with similar results for analyses based on population risks and from utility scores. Regression analysis showed that the risk of breast cancer ( p <.001) was the only disease risk that was statistically significantly associated with women's preferences. Conclusions Women had significant preferences over the different risk profiles, primarily due to the incremental effect on changes in values for the risk of breast cancer. Therefore, studies evaluating therapies for osteoporosis should consider patient preferences for living with different risk profiles.

Energy Transfer from Photoexcited Electronic States to the Thermal Modes

Abstract Energy transfer processes from a photoexcited ion and molecules to solvents were studied from the rate of the temperature rise of the solvent using several newly developed techniques: temperature grating, temperature lens, acoustic peak delay, and molecular heater–molecular thermometer methods. These energy transfer processes are closely related to the well-studied vibrational relaxation (cooling) process but the overall energy transfer process can be monitored by detecting the time course of the matrix heating. In aqueous solution, most of the energy of a photoexcited ion transfers to the thermal mode within 2–3 ps after the populational relaxation to a lower electronic state. In organic solvents, the process is described by roughly two kinetics: fast ( ≤ 1 ps) and slow (20–30 ps). This two-phase kinetics was explained by a simple thermalization model; the initial fast process represents the energy transfer to the doorway molecules in the first solvent shell molecules and the slower one represents the thermal diffusion process from the hot solvent molecules to the bulk solvent molecules. A new molecular heater-molecular thermometer integrated system is also described.

Inhibition Effect of Hydantoin Compounds on the Corrosion of Iron in Nitric and Sulfuric Acid Solutions

Summary. The inhibition of corrosion of iron in 2 M nitric acid and 2 M sulfuric acid solutions by substituted phenylhydantoin, thiohydantoin, and dithiohydantoin compounds was measured using thermometric, weight loss, and polarization methods. The three methods gave consistent results. The polarization curves indicated that the hydantoin compounds act as mixed-type inhibitors. The adsorption of the inhibitors were found to obey the Temkin adsorption isotherm. The higher inhibition efficiency of the additives in nitric with respect to sulfuric acid solution may be attributed to the reduced formation of soluble quaternary nitrogen salts in nitric acid medium, favouring adsorption of the parent additive on the metal surface. The obtained results indicate that the corrosion rate of iron in both acids increases with increasing temperature, both in absence and presence of the tested inhibitors. Kinetic-thermodynamic model functions and Temkin isotherm data are compared and discussed. The synergistic effect of halide anions on the inhibition efficiency of the hydantoin compounds was also investigated.

Hydrogeology and geochemistry in the Curuksu (Denizli) hydrothermal field, western Turkey

Curuksu is a low temperature hydrothermal system located within the upper sector of the B. Menderes Graben. The hydrologic structure of the Curuksu hydrothermal system is largely controlled by major graben faults where it is characterized by the presence of two thermal reservoirs. One is formed by Paleozoic quartzite, schist and marble units, and the second consists of Pliocene limestone-travertine units. The thermal conditions in the Curuksu region indicate that the regional tectonics and resulting local stress field control low temperatures activity. Temperatures of 30 springs emerging in the study area range between 15 and 55 °C. These springs are classified as cold fresh, warm mineral and thermal waters. Pamukkale, Karahayit and Honaz springs are steam condensate waters, whereas Curuksu springs are commonly steam-heated waters with respect to the major anion concentrations. The reservoir temperatures have been estimated from chemical compositions by utilizing simultaneously, geothermometers and mixing models. According to these thermometric methods, the most probable subsurface temperature is in the range of 62–90 °C. However, the mixing models suggest a temperature level of 80 °C for the parent water. The system has low total dissolved solid (TDS) of ∼1000–1500 mg/l, which indicate that these waters undergo conductive cooling within the reservoir.

Measurement of sap flow in roots of woody plants: a commentary.

Measurements of sap flow in roots have recently been used to study patterns of resource acquisition by woody plants; however, the various thermometric methods employed have yielded disparate findings. These findings may be harmonized by accounting for the phenomenon of reverse sap flow in roots. We suggest that only methods capable of measuring slow and reverse rates of flow and that do not require assumptions of zero flow during the night are applicable to studies with roots. The heat ratio method and the constant power heat balance method fit these criteria, whereas the constant temperature heat balance, compensation heat pulse and thermal dissipation methods do not.

Volume changes during melting and heating of silicon and germanium melts

The temperature dependence of the density of silicon and germanium in the neighborhood of the crystal-melt phase transition is investigated by an improved thermometric method. Changes in volume occurring during transition from the solid to the liquid state are estimated. It is shown that the density increases in the process of crystal-melt phase transition and, accordingly, the specific volume decreases in both silicon and germanium; an increase in pressure noticeably decreases the melting points of both investigated substances. A linear temperature dependence of density in the liquid phase is obtained. The strength characteristics of interatomic bonds are estimated such as the characteristic Debye temperatures and root-mean-square dynamic displacements of atoms from the equilibrium position in the short-range order structure of the melts of the investigated substances. It is shown that the melting process noticeably weakens the cohesive forces between particles and substantially changes the pattern of their oscillation spectrum.

Inhibitive effect of some Schiff bases on corrosion of aluminium in hydrochloric acid solutions

Mass loss and thermometric methods have been used to study the inhibition of aluminium corrosion in HCl solution by four Schiff bases: 2-anisalidine-pyridine; 2-anisalidine-pyrimidine; 2-salicylidine-pyridine; and 2-salicylidine-pyrimidine. Values of inhibition efficiency obtained from the two methods are in good agreement and are dependent upon the concentrations of inhibitor and acid.

Body Heat Balance of a Man with Deficient Sweat Rate Subjected to Physical Work in a Hot Environment

The dynamics of physiological stress and thermal balance were investigated in men subjected to endogenous and exogenous heat loads. The study was conducted using the thermometric method. Substantial differences in the dynamics of the tested parameters and their quantitative characteristics were observed in 1 out of 8 participants. In this article, the observed differences are rationalized in terms of the deficient sweat rate mechanism. It is pointed out that it is indispensable to address these cases in work safety regulations.

97/04534 Combustion behavior of low-rank coal water slurries: Yavuz, R. et al. Proc. Annu. Int. Pittsburgh Coal Conf., 1996, 13, (1), 500–505

Coal water slurries have been developed over the last 15 years as an alternative to fuel oil mainly in industry and power station boilers. Observing of droplet lifetime reveals details of the mechanism of the slurry combustion. In the present investigation, single droplet combustion of lignite water slurries using different Turkish lignites were experimentally studied by using single droplet combustion technique. The technique is based on thermometric method. Results of combustion behavior of low rank coal water slurries were compared with that of high rank coal water slurries which were found in the literature.

Thermometric measurements of the self-field losses in silver sheathed PbBi2223 multifilamentary tapes

Self-field ac losses in Ag sheathed PbBi-2223 tapes were measured using a thermometric method, which determines the losses by measuring the temperature profile of a vacuum insulated sample, with both ends at a fixed temperature. In practice, the samples were placed in a vacuum capsule immersed in LIN bath. By minimizing the bath superheat, thermal emf and heating at the current contacts, a loss induced temperature increase as low as 2 mK was measured using a Si diode thermometer. With a typical sample length of 600 mm, self-held losses between 7/spl times/10/sup -6/ W/m and 4/spl times/10/sup -3/ W/m were measured at different frequencies. The results are in good agreement with both the electric measurement and theoretical calculation. This provides the first independent confirmation that electric measurement with carefully placed voltage loops can give the true losses of the sample.

Enzymatic Polymerization of Phenolic Biomonomers Derived from Cashew Nut Shell Liquid

Enzymatic polymerization of alkyl phenols derived from a renewable resource, viz., cashew nut shell, has been carried out in a dioxane-water mixture. The reaction and reaction products have been characterized by a number of spectroscopic, microscopic, and thermometric methods. These monomers have also been copolymerized with various substituted phenols. The homopolymers are soluble in organic solvents while the copolymers are crosslinked, with negligible solubility. Enzymatic polymerization in a dioxane-water solvent mixture results in spherical particles in the case of homopolymerization while structures without distinctive morphologies are obtained in the case of copolymerization. The effects of dioxane-water composition and solution pH on the polymerization reaction have also been explored.

Propagation of a thermal instability in high-Tcsuperconductor

In the thermometric mapping method a large thermal gradient is created along a high-Tcsuperconducting sample. By keeping the lower end of the specimen near liquid nitrogen temperature and by varying the top temperature from above the onset temperature down to the critical temperature, normal and superconducting domains come into being, depending on the microstructure of the specimen and actual values of the local temperature. This operation results in a spatial and temporal change of superconducting and normal states. If a thermal pulse is also applied, it leads to a thermodynamically unstable state, characterized by an oscillation of d.c. and a.c. voltages detectable on samples. The speed of propagation of this effect can be determined on the basis of average transformation times of different experiments, providing values of 0.25–0.33 mm s−1for Y–Ba–Cu–O specimens.

Characteristics of the a.c. losses in Ag-sheathed PbBi2223 tapes

A mini review of our latest results on the a.c. losses in Ag-sheathed PbBi2223 tapes is presented with the focus on self-field losses in a variety of situations and external losses with and without a d.c. transport current. Comparative measurements with the thermometric and electric methods have demonstrated the validity of the electric method despite the problem of a distribution of the loss electric field. Using these two methods the effect of a longitudinal distribution of critical current along the tape has been shown. The influence of a transverse distribution of the local J c through the core of the tape is also examined. Studies of the magnetic field dependence of the self-field losses have shown that different regions of the core have a different J c( B) dependence, in contrast to the temperature dependence where all regions of the core show a similar dependence. Measurements at higher frequencies show the importance of flux diffusion where an increased dB dt gives an increased induced critical current. At sufficiently higher frequencies (> 200 Hz) the self-field of the core is shown to induce eddy current losses within the silver sheath of the tape. For the external a.c. field case in parallel fields the losses are well described by the infinite slab geometry. For the case of the perpendicular field the losses are considerably less than those expected from either the thin ellipse or rectangle geometry. Possible mechanisms for this discrepancy include granularity of the tape or partial uncoupling of the filaments. For the combined action of an a.c. external field and a d.c. transport current our results show that the total losses cannot be obtained using only using a pick-up loop to measure the flux changes within the tape. An additional loss sustained by the d.c. current source also needs to be measured via a pair of voltage taps.

Thermometric Sensing of Fluoride by Adsorption on Ceramic Hydroxyapatite Using Flow Injection Analysis

A thermometric method for detection of fluoride has been developed that relies on the specific interaction of fluoride with hydroxyapatite. The detection principle is the measurement of the enthalpy change upon adsorption of fluoride onto the ceramic hydroxyapatite by temperature monitoring using a thermistor-based flow injection calorimeter. The detection limit for fluoride was 5 µM (0.1 ppm) which is in the same range as that of a commercial ion-selective electrode. The method could be applied to fluoride in aqueous solution as well as in cosmetic preparations. The system yielded highly reproducible results over at least 6 months without the need for replacing or regenerating the ceramic hydroxyapatite column. The ease of operation of thermal sensing and the ability to couple the system to flow injection analysis provides a versatile, low-cost and fast detection method for fluoride.

Direct creation of vortex-glass state in high-T c superconductors by an actually dynamic method

A new, dynamic procedure is elaborated to create vortex-glass state in high-Tc superconductors, which consists of the application of the thermometric mapping method together with a thermal pulse. This results in the direct determination of main parameters of the given state, providing vortex-glass transition temperature of 88 K, correlation length of 2.1 mm, characteristic time of 15 s, moreover static and dynamic scaling exponents of 1.1 and 3.7, respectively.

Thermometric titrations of amines with nitrosyl perchlorate in acetonitrile solvent

Thirteen aliphatic and four aromatic amines, namely diethylamine, triethylamine, n-propylamine, di- n-propylamine, tri- n-butylamine, isopropylamine, di-isopropylamine, n-butylamine, di- n-butylamine, tri- n-butylamine, isobutylamine, sec-butylamine, tert-butylamine, aniline, N,N-dimethylaniline, 2-nitroaniline and 4-nitroaniline were titrated thermometrically with nitrosyl perchlorate in acetonitrile solvent. All the aliphatic amines gave very well-shaped thermometric titration curves. The calculated recovery values of the amines were very good. In comparison, the aromatic amines, aniline and N,N-dimethylaniline gave rather well-shaped titration curves, but the recovery values were fairly low. 2-Nitro- and 4-nitro anilines gave no thermometric response at all. The heats of reaction of the amines with nitrosyl perchlorate are rather high. However, the average heat of reaction of the aromatic amines is approximately two-thirds that of the average heat of the aliphatic amines. To support this method all the amines were also titrated potentiometrically and very similar results to those obtained with the thermometric method are seen. The nitrosyl ion is a Lewis acid, strong enough to titrate quantitatively aliphatic amines in acetonitrile solvent, but not strong enough to titrate aromatic amines at the required level in the same solvent.

Geochemical approach to the Bou Hadjar hydrothermal system (NE Algeria)

The Bou Hadjar low-temperature hydrothermal system is located in northeast Algeria. The four main thermal springs that are the subject of the study emerge ith temperatures between 32 and 60°C from allochthonous formations. The reservoir temperature has been estimated from chemical compositions by utilizing simultaneously the silica, gas and sulfate-water oxygen isotope geothermometers, fluid-mineral equilibrium calculations, and a mixing model. According to these thermometric methods, the most probable subsurface temperature is in the range 75–106°C. The mixing model suggests a temperature of 125°C for the parent water.

Gas-based temperature measurements in the range of the ITS-90

The survey is intended to provide up-to-date information on the developments in thermometry involving the use of gaseous substances. The use of well specified thermodynamic states of condensed gases as fixed temperature points (2.2–220 K) is illustrated, and the sealed-cell method described as the most effective for their realization. Secondly, thermometric methods exploiting a pressure-temperature relationship are described. For the gaseous state, the developments in gas thermometry (1–300 K) are illustrated, not only for absolute thermometry, but also for interpolating thermometers (as required, e.g., by the ITS-90), and for simple and practical self-contained devices. Subsequently, in connection with condensed gases, developments in vapour-pressure thermometry are described.

Mechanical behavior of Al 2O 3 ceramics under cyclic tension-compression loading

During cyclic deformation, temperature measurements were carried out with thermocouples. On the basis of the thermoelastic effect, a thermometric method is described which allows the determination of the elastic part of the total deformation. Thus effective stress changes can be determined. The system is quite sensitive and makes it possible to characterize the behavior of a small volume unit during cyclic deformation. The temperature change ΔT is directly related to the stress change Δσ according to Thomson's formula. Notched Al 2O 3 specimens were tested under direct tension-compression loading. Cyclic tests with a stepwise load increase were carried out using a tensile tester and a servohydraulic test system. The test frequency was 0.5 and 5 Hz and the stress ratio was R = −1. Load differences and corresponding changes of temperature were measured. By means of the temperature measurements, the notch factor can be determined. It can be shown that the calculated stress concentration in the notched area is much higher than the measured value. This indicates that the stress reduction in Al 2O 3 is higher than in non-brittle materials. The predominant mechanism causing reduction of the stress concentration is microcracking. Fractographic studies with the scanning electron microscope show damage of Al 2O 3 under cyclic loading conditions.

Inhibitory Effect of some carbazides on corrosion of aluminium in hydrochloric acid and sodium hydroxide solutions

AbstractThe dissolution of aluminium in hydrochloric acid and sodium hydroxide solutions in the presence of semicarbazide, thiosemicarbazide and sym.diphenylcarbazide as corrosion inhibitors has been studied using thermometric, weight‐loss and polarization methods. The three methods gave consistent results. The higher inhibition efficiency of these compounds in acidic than in alkaline madia may be due to the less negative potential of aluminium in hydrochloric acid solution, favouring adsorption of the additive. The adsorption of these compounds were found to obey Frumkin adsorption isotherm.Cathodic polarization measurements showed that these compounds are cathodic inhibitors and their adsorption in the double layer does not change the mechanism of the hydrogen evolution reaction. The results are analysed in terms of both molecular and cationic adsorption.