Thermometric Method Research Articles

Investigating steam penetration using thermometric methods in dental handpieces with narrow internal lumens during sterilizing processes with non-vacuum or vacuum processes

Dental handpieces are required to be sterilized between patient use. Vacuum steam sterilization processes with fractionated pre/post-vacuum phases or unique cycles for specified medical devices are required for hollow instruments with internal lumens to assure successful air removal. Entrapped air will compromise achievement of required sterilization conditions. Many countries and professional organizations still advocate non-vacuum sterilization processes for these devices. To investigate non-vacuum downward/gravity displacement, type-N steam sterilization of dental handpieces, using thermometric methods to measure time to achieve sterilization temperature at different handpiece locations. Measurements at different positions within air turbines were undertaken with thermocouples and data loggers. Two examples of widely used UK benchtop steam sterilizers were tested: a non-vacuum benchtop sterilizer (Little Sister 3; Eschmann, Lancing, UK) and a vacuum benchtop sterilizer (Lisa; W&H, Bürmoos, Austria). Each sterilizer cycle was completed with three handpieces and each cycle in triplicate. A total of 140 measurements inside dental handpiece lumens were recorded. The non-vacuum process failed (time range: 0-150s) to reliably achieve sterilization temperatures within the time limit specified by the international standard (15s equilibration time). The measurement point at the base of the handpiece failed in all test runs (N=9) to meet the standard. No failures were detected with the vacuum steam sterilization type B process with fractionated pre-vacuum and post-vacuum phases. Non-vacuum downward/gravity displacement, type-N steam sterilization processes are unreliable in achieving sterilization conditions inside dental handpieces, and the base of the handpiece is the site most likely to fail.

Calibration and comparison of thermal dissipation, heat ratio and heat field deformation sap flow probes for diffuse-porous trees

Sap flow probes are routinely used in forest and horticulture hydrology for estimating tree water use. This requires unbiased measurements when upscaling from tree to stand level, but accuracy and comparability of different thermometric methods have been questioned. Three sap flow measuring techniques were compared against gravimetric flow measurement in cut stem segments: ‘Granier-type’ thermal dissipation probes (TDP; three different sensor types), the heat field deformation method (HFD), and the heat ratio method (HRM). For the empirical methods (TDP and HFD), new calibration parameters were estimated using a nonlinear hierarchical modelling approach. 66 stem segments from five temperate, diffuse-porous tree species (9–16cm stem diameter, 100cm stem length) were exposed to a wide range of flux densities by applying subatmospheric pressure (−50 to −650hPa) analogous to natural flow conditions in the field.All TDP probes underestimated flux density by 23–45% when calculated with Granier's original calibration parameters, with the deviation increasing with flux rate. The accuracy was significantly improved by estimating new calibration parameters, especially for probes differing from Granier's original sensor design. Species-specific parameters further improved accuracy, although the species differences might partially be explained by variation in the observed ranges of sap flux. The HFD sensor overestimated gravimetric flow by ∼11%; empirical calibration did not improve its accuracy compared to the manufacturer's equation. At low to medium flow rates, the HRM system achieved higher accuracy than the other probes (0.8% underestimation), while performing poorly at high flux rates under our measurement settings (energy input of 25J). Both for TDP and HFD sensors, we observed a surprisingly large variability in calibration parameters between different stems of the same species.We conclude that (i) TDP and HFD sensors require species-specific calibration to measure sap flux with high accuracy, (ii) the original Granier equation cannot be used for TDP probes with deviating design, and (iii), at low to medium flow rates, the highest accuracy can be achieved with HRM sensors. Our results help to increase the accuracy of tree sap flow measurements with thermal dissipation probes, and to assess various levels of errors related to the different thermometric methods. This is important when synthesizing forest transpiration data on regional and global scales.

Evaluation of pawpaw leaves extract as anti-corrosion agent for aluminium in hydrochloric acid medium

Pawpaw leaves extract was examined as anti-corrosion agent for aluminium in hydrochloric acid medium. The extract and corrosion product were analyzed using Fourier transform infrared spectrophotometer (FTIR). Thermometric, gravimetric, potentiodynamic polarization and scanning electron microscopic methods were employed in the study. The inhibition efficiency was optimized using Response Surface Methodology (RSM) of Design Expert Software 9. Inhibitor concentration (0.2 g/l – 1.0 g/l), temperature (303 K – 333 K) and time (1hour - 5 hours) were the considered factors. It was revealed that stretched C-H and O-H functional groups were predominantly responsible for the corrosion inhibition process. The adsorption of the extract on the aluminium surface adhered to the mechanism of physical adsorption. A quadratic model adequately described the inhibition process. Optimum inhibition efficiency of 80.58% was obtained at inhibitor concentration of 0.961 g/l, temperature of 311.459 K and time of 3.932 hrs. The extract is a mixed-type inhibitor that can control both cathodic and anodic corrosion. http://dx.doi.org/10.4314/njt.v36i2.241

Оценка изменений структурно-энергетического состояния воды при охлаждении, нагревании и действии магнитного поля с использованием термометрии и электрофизических методов исследования

Оценка изменений структурно-энергетического состояния воды при охлаждении, нагревании и действии магнитного поля с использованием термометрии и электрофизических методов исследования

Thermophysical and chemical properties of bioliq slags

The challenges of future regarding the energy supply are linked to the limitation of fossil fuels, the avoidance of climatic relevant gases, and the worldwide increasing demand for energy. Therefore, the future energy supply is characterized by the increase of renewable energy: sun, water, wind and biomass. Entrained flow gasification of biomass is promising, since it is a highly efficient and flexible process. Low-grade fuels are chemically transformed at high temperatures (>1200°C) and pressures (up to 80bar) into synthetic fuels. The inorganics of the fuel are converted into a slag, which forms a layer in the reactor. The thermophysical and chemical properties of the slag are defining the conditions and limitations of the gasification process. In this study, the fundamental thermophysical properties of bioliq slags are determined, in order to describe the heat transfer and the flow of the slag across the reactor by CDF-modelling of the bioliq-gasifier within the HVIGasTech project. By using a high temperature viscometer the viscosity and flow behavior of the slag were determined. In addition, the density and surface tension were measured by the sessile drop method. Thermometric and calorimetric methods were used to provide a detailed view onto the slags heat capacity and phase transitions. Thermodynamic calculations using FactSage and an in-house developed thermodynamic database for available solution phases and compounds were performed to obtain information about the ash-slag transformation.

Genetically encoded ratiometric fluorescent thermometer with wide range and rapid response.

Temperature is a fundamental physical parameter that plays an important role in biological reactions and events. Although thermometers developed previously have been used to investigate several important phenomena, such as heterogeneous temperature distribution in a single living cell and heat generation in mitochondria, the development of a thermometer with a sensitivity over a wide temperature range and rapid response is still desired to quantify temperature change in not only homeotherms but also poikilotherms from the cellular level to in vivo. To overcome the weaknesses of the conventional thermometers, such as a limitation of applicable species and a low temporal resolution, owing to the narrow temperature range of sensitivity and the thermometry method, respectively, we developed a genetically encoded ratiometric fluorescent temperature indicator, gTEMP, by using two fluorescent proteins with different temperature sensitivities. Our thermometric method enabled a fast tracking of the temperature change with a time resolution of 50 ms. We used this method to observe the spatiotemporal temperature change between the cytoplasm and nucleus in cells, and quantified thermogenesis from the mitochondria matrix in a single living cell after stimulation with carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, which was an uncoupler of oxidative phosphorylation. Moreover, exploiting the wide temperature range of sensitivity from 5°C to 50°C of gTEMP, we monitored the temperature in a living medaka embryo for 15 hours and showed the feasibility of in vivo thermometry in various living species.

From thermometric to spectrophotometric kinetic-catalytic methods of analysis. A review

Kinetic-catalytic analytical methods have proved to be very easy and highly sensitive strategies for chemical analysis, that rely on simple instrumentation [1,2]. Molecular absorption spectrophotometry is commonly used as the detection technique. However, other detection systems, like electrochemical or thermometric ones, offer some interesting possibilities since they are not affected by the color or turbidity of the samples. In this review some initial experience with thermometric kinetic-catalytic methods is described, up to our current experience exploiting spectrophotometric flow techniques to automate this kind of reactions, including the use of integrated chips. Procedures for determination of inorganic and organic species in organic and inorganic matrices are presented.

Assessing the accuracy of globe thermometer method in predicting outdoor mean radiant temperature under Malaysia tropical microclimate

Assessing outdoor human thermal comfort and urban climate quality require experimental investigation of microclimatic conditions and their variations in open urban spaces. For this, it is essential to provide quantitative information on air temperature, humidity, wind velocity and mean radiant temperature. These parameters can be quantified directly except mean radiant temperature (Tmrt). The most accurate method to quantify Tmrt is integral radiation measurements (3-D shortwave and long-wave) which require using expensive radiometer instruments. To overcome this limitation the well-known globe thermometer method was suggested to calculate Tmrt. The aim of this study was to assess the possibility of using indoor globe thermometer method in predicting outdoor mean radiant temperature under Malaysia tropical microclimate. Globe thermometer method using small and large sizes of black-painted copper globes (50mm, 150mm) were used to estimate Tmrt and compare it with the reference Tmrt estimated by integral radiation method. The results revealed that the globe thermometer method considerably overestimated Tmrt during the middle of the day and slightly underestimated it in the morning and late evening. The difference between the two methods was obvious when the amount of incoming solar radiation was high. The results also showed that the effect of globe size on the estimated Tmrt is mostly small. Though, the estimated Tmrt by the small globe showed a relatively large amount of scattering caused by rapid changes in radiation and wind speed.

Alternating and Rotational Losses Up to Magnetic Saturation in Non-Oriented Steel Sheets

A three-phase magnetizer has been developed, by which non-oriented Fe-Si steel sheets can be characterized under alternating and rotational flux up to a polarization value $J_{p}\approx 0.98~J_{s}$ , where $J_{s}$ is the saturation magnetization. The loss measurements, performed in the frequency range 2 Hz–1 kHz, require the combination of field-metric and thermometric methods, besides fine control of the induction wave-shape/loci under the required demanding exciting conditions. By exploiting the loss separation concept, it is observed that under rotational flux, both the hysteresis and excess loss components monotonically decrease with $J_{p}$ , to disappear at saturation. The measured losses then become equal to the calculated classical losses. This could actually be predicted, because of the expected disappearance of the domain walls under saturating rotational field, but it has never been previously verified by the experiments.

Modeling the Corrosion Inhibition of Mild Steel in HCl Medium with the Inhibitor of Pawpaw Leaves Extract

Modeling the corrosion inhibition of mild steel in HCl medium with inhibitor of pawpaw leaves extract is presented. The extract was analyzed using gas chromatography - mass spectrometry . Thermometric and gravimetric methods were employed in the corrosion inhibition study. The inhibition efficiency w as modeled and optimized using response surface methodology (RSM) . It was observed that the free energy of adsorption ( ∆ G ads ) was negative and less than the threshold value of - 40 kJ/mol . T he adsorption of the extract was spontaneous , and occurred according to the mechanism of physical adsorption . A quadratic model was generated, with optimum i nhibition efficiency of 80.29 % obtained. The extract was highly efficient in the corrosion control process . It is effective for surface treatment of mild steel in the acid medium. Therefore, i t is recommended that pawpaw leaves extract should be employed as corrosion inhibitor in oil well acidizing and surface treatment of mild steel .

Pyrometric temperature measurements with a miniature cavity used as a blackbody in the calorimetric method for determining absorbed laser energy

As a result of improvements introduced in the design parameters of detectors, the miniaturization of measuring gauge and software upgrades, today’s single band pyrometers are robust devices with innovative solutions developed to enhance their performance. Despite technological advances, entering the correct value of emissivity coefficient of an object in the pyrometric measuring system is still an unsolved problem. One of the possible solutions may be using a blackbody to a greater extent. This study attempts to use a miniature cavity as a blackbody in pyrometric temperature measurements of a metal part, conducted according to the so-called calorimetric (thermometric) method of determining the laser energy transferred to the part. The method helps measure the temperature of a laser-processed material that acts as a calorimeter. Temperatures are normally measured using thermocouples bonded to the laser-treated element, but this technique is not free from limitations. Some of them can be eliminated through pyrometric measurements. The experimental investigations involved simultaneous temperature measurements with the use of a thermocouple fixed to the processed element and a pyrometer for measuring the temperature of the miniature blackbody cavity produced in the material. Comparative study results support the use of a blackbody for calorimetric non-contact temperature measurements of laser energy absorbed in the welded part in laser beam welding.

Comparison between five risk assessment methods of patient handling

Several methods currently exist to assess risks resulting from manual handling of patients, based on various perspectives and analyzing different working conditions in the health-care sector. For that reason, a comparison of the main tools properties is discussed in the current study, establishing their strengths and weaknesses in order to provide guidance for the selection of a potential ideal method to use. The comparison is done based on ten items selected from MAPO, DINO, PTAI, Care Thermometer and Dortmund Approach methods, by qualifying each one with different scores, according to a predetermined criterion. For this purpose, a previous fieldwork was performed in various hospital wards and operating rooms of a public health service hospital, comparing the results of partial and total scores. It was observed that, although the five methods compared are similar in nature, the methodology of each them is different and, therefore, the results obtained are unequal. On one hand, it was found that MAPO, PTAI and Care Thermometer methods provide a more balanced approach on the different variables that, in a preventive level, influence the patient handling. On the other hand, it was evidenced that DINO and Dortmund Approach methods focus almost exclusively on the technical work of the caregiver and on the detailed postural analysis that determines the lumbar load, respectively. As a conclusion, we believe that it is necessary to advance with the improvement of these tools, and in this sense we propose the basic lines of a method that integrates those factors that were top rated.

Thermodynamic Study of Corrosion Inhibition of Mild Steel in Corrosive Medium by Piper nigrum Extract

Background/Objectives: Introduction of green corrosion inhibitor can stop the use of expensive and harmful synthetic inhibitor. This study investigates the corrosion inhibition of mild steel in aggressive media by using Piper nigrum extract. Methods/Statistical Analysis: The potentiality of Piper nigrum to inhibit corrosion was studied based on concentration of inhibitors range of 0.2g/l-0.5g/l and temperature range of 40°C-60 °C by using gravimetric and thermometric methods. Results: Calculation from weight loss method revealed that Inhibition Efficiencies (IE%) increase with increasing inhibitor concentration which show a decrease in Corrosion Rate (CR). However, the rise in temperature decreases the IE% which means an increasing in the CR. Furthermore, thermodynamic parameters of adsorption process such as Activation Energy (Ea), Enthalpy (ΔH° ) and Entropy (ΔS° ) were calculated and these values showed a good interaction. A rise of Ea values with increasing inhibitor concentration proved a physical adsorption mechanism is taking place. The ΔH° calculated proved that this is an endothermic process. Conclusion/Application: Results from this study showed that Piper nigrum was an attractive alternative to prevent corrosion as it shows the great inhibition efficiency.

Kinetic Study on Sodium Sulfate Synthesis by Reactive Crystallization

In this work, the kinetics of the reaction between sodium chloride and sulfuric acid, in aqueous solution and in the presence of ethanol as antisolvent, was studied as a function of each reactant concentration and temperature. The thermometric method was implemented to fit the experimental data obtained in an adiabatic batch reactor. The initial reaction rate methodology was applied to determine the order of reaction as well as the specific reaction rate constants. The reaction rate corresponded to an elementary reaction. Good agreement between experimental and simulation temperature profiles was achieved (absolute average deviation (AAD) of ∼1.15%). The reactive crystallization process was found to be very selective to anhydrous Na2SO4, with yields higher than 95 wt %.

Effects of filler wire on residual stress in electron beam welded QCr0.8 copper alloy to 304 stainless steel joints

Abstract The electron beam welding (EBW) of 304 stainless steel to QCr0.8 copper alloy with or without copper filler wire was studied in detail. The temperature fields and magnitude and distribution of stress fields in the joints during the welding process were numerically simulated using finite element method. The temperature cycles and residual stresses were also experimentally measured by thermometric and hole-drilling methods, respectively. The accuracy of the modeling procedure was verified by the good agreement between the calculated results and experimental data. The temperature distribution in the joint was found to be asymmetric along the center of weld. In particular, the temperature in the copper alloy plate is much higher than that in the 304 SS plate owing to the great difference in thermal conductivity between the two materials. The peak three-dimensional residual stresses all appeared at the interface between the copper and steel in the two different joints. Furthermore, the weld was subjected to tensile stress. The longitudinal residual stress, generally the most harmful to the integrity of the structure among the stress components in EBW with filler wire (EBFW), was 53 MPa lower than that of autogenous EBW (AEBW), and the through-thickness residual stress was 12 MPa lower. The transverse residual stress of EBFW was 44 MPa higher than that of AEBW. However, analysis of the von Mises stress showed that the EBFW process effectively reduced the extent of the high residual stress region in the weld location and the magnitude of the residual stresses in the copper side compared with those of the AEBW joint.

Inhibitive and Synergistic Properties of Ethanolic Extract of Moringa oleifera Leaves on the Corrosion of Zinc in HCl Solution

The potentials of ethanolic extract of Moringa oleifera leaves as corrosion inhibitor was investigated by evaluating the corrosion behaviour of Zinc immersed in 0.5M, 1.0M, 1.5M and 2.0M HCl (corrodent) solutions each containing varied concentration of the extract (0.1 g/L, 0.3 g/L and 0.5 g/L) and halides (0.1M, 0.3M and 0.5M each of KCl and KI) for synergism using thermometric method. Maximum temperature attained, reaction time, synergism parameter and adsorption characterizations were utilized to evaluate the corrosion inhibition, synergism and adsorption properties of the extract. The results revealed that the corrosion of Zinc decreases with increase in concentration of ethanol extract and halides which are both inhibitors; also, it increases with increase in HCl (corrodent) concentration. The addition of KI and KCl to the extract, improve the values of inhibition efficiency of the extract in the order KI > KCl. In all cases, KI exhibits least effect on the corrosion of Zinc in comparison with KCl. Results obtained from adsorption studies indicated

The inhibitive action of chitosan extracted from Archachatina marginata shells on the corrosion of plain carbon steel in acid media

Purpose– The purpose of this investigation was to study the inhibitive action and adsorption potential of chitosan extracted fromArchachatina marginatasnail shells on the corrosion of plain carbon (mild) steel in acid media.Design/methodology/approach– Weight loss and thermometric methods were used during this investigation. Characterization of the obtained chitosan was accomplished with Fourier transform infrared spectroscopy analysis. The effects of parameters influencing the inhibition process (concentration and temperature) were evaluated, and the sorption isotherms and thermodynamic parameters were derived.Findings– The results obtained showed that chitosan has good inhibition potential with an efficiency of 93.2 per cent. The inhibition efficiency decreased with an increase in temperature but increased with increasing concentration of chitosan. Test results best fitted the Langmuir Isotherm with a correlation coefficient (R2) of 0.999. The thermodynamic parameters studied reveal that the adsorption of chitosan on the surface of mild steel is spontaneous.Originality/value– The paper fulfills an identified need in finding solutions to the problems of metal corrosion using agricultural wastes.

Research of the quantitative content of liquefied gas by using model liquid systems

This paper presents the experimental research method for the choice of a liquid system model, which has a similar to liquefied petroleum gas structure, and also the determination of its temperature dependence. That makes it possible to verify the proposed thermometric method adequacy for quantitative content determining of the liquefied petroleum gas. This method allows to determine the quantitative content of not only the main mixture components (propane and butane) with different temperatures, but the content of impurities such as ethylene, propylene, butylene, amylene, heksylen, heptylen etc., which can improve the quantitative content accuracy of condensed petroleum gas components. Among the studied substances, such as toluene, isooctane, hexane, authors have found a compound that can be the optimal liquid system model and can be used as a reference based on which the density of liquefied petroleum gas and its quantitative value will be determined.

How significant is nocturnal sap flow?

Nocturnal sap flow (Qn) has been found to occur across many taxa, seasons and biomes. There is no general understanding as to how much Qn occurs and whether it is a significant contribution to total daily sap flow (Q). A synthesis of the literature and unpublished data was made to determine how significant is Qn, as a proportion of Q (%Qn), across seasons, biomes, phylogenetic groups and different thermometric sap flow methods. A total of 98 species were analysed to find that %Qn, on average, was 12.03% with the highest average dataset of 69.00%. There was significantly less %Qn in winter than in other temperate seasons, and significantly less %Qn in the wet season than in the dry season. The equatorial and tropical biomes had significantly higher %Qn than the warm temperate and nemoral biomes. The heat ratio method (HRM) and the thermal dissipation (TDP) method had significantly higher %Qn than the heat balance method. Additional analysis between HRM and TDP found HRM to have significantly higher %Qn in winter, wet season and various biomes. In all but one out of 246 cases Qn occurred, demonstrating that Qn is significant and needs to be carefully considered in sap flow and related studies.

Comparison of mean radiant temperature from field experiment and modelling: a case study in Freiburg, Germany

Mean radiant temperature (T mrt) based on two measurement methods and outputs from three models are compared in this study. They are the six direction radiation method, globe thermometer method, RayMan model, ENVI-met model and SOLWEIG model. The comparison shows that globe thermometer method may overestimate the T mrt since wind velocity is a key variable in the estimation based on this method. For better estimation, T mrt measured by the globe-thermometer method be corrected by the imported wind speed (stable, low and assuming wind speed) and validated by the six-direction radiation method. The comparison of models shows that the RayMan model’s evaluation of T mrt involving global radiation with fine time resolution was better than the corresponding evaluations under the other two models (ENVI-met and SOLWEIG) in this case. However, the RayMan model can only assess T mrt for a one-point one-time context, whereas the other two models can evaluate two-dimensional T mrt. For two-dimensional evaluations of T mrt, SOLWEIG have a better prediction of T mrt than ENVI-met, and ENVI-met can simulate several different variables, which are wind field, particle distribution, CO2 distribution and the other thermal parameters (T a, surface temperature and radiation fluxes), that SOLWEIG cannot.