Temperature Rise Of Sample Research Articles

Design and Experimental Study of a Drilling Tool for Mars Rock Sampling

Martian rocks contain crucial information about the genesis of Mars and the historical evolution of Martian climate change. Consequently, extracting and examining Martian rocks are pivotal in advancing our comprehensive understanding of the red planet. However, the current core drill string is prone to wear and tear, and the samples are susceptible to thermal denaturation. To address these challenges, we introduce two novel types of drill bits, the conical straight junk slot and the conical spiral junk slot, both employing impregnated diamond as the primary material. Comparative experiments were meticulously conducted to evaluate the influence of different junk configurations on drilling parameters, including speed, abrasion resistance, drilling force loading, and sample temperature rise. The findings unequivocally demonstrate the superior performance of the spiral junk slot. Furthermore, simulations were performed to examine the drilling process on basalt using a fixed configuration drill bit, validating the occurrence of the sample temperature rise. The research presented in this paper offers valuable programmatic references and essential data support for future Martian rock coring drilling missions.

Effects of Conveyor Movement, Layer Rearrangement and Sample Mixing on Pest Mortality in Milled Rice Subjected to Radio Frequency Heating

Highlights Hot air-assisted RF heating accelerated temperature rise of samples. Thermal holding after RF heating improved heating uniformity and pest mortality. Layer rearrangement, conveyor movement, and mixing enhanced RF heating efficiency. Abstract. Application ofradio frequency (RF) treatment has been studied for disinfesting agricultural products, and RF heating non-uniformity has been demonstrated to directly influence pest mortality in treated products. The purpose of this study was to investigate the combined effects of holding time after conveyor movement, layer rearrangement, and sample mixing on the mortality of Rhyzopertha dominica (R. dominica) in milled rice treated with hot air-assisted RF heating. Results showed that hot-air assistance during the process of RF heating can lead to a rapid temperature rise and improve the temperature distribution. RF heating followed by holding samples in hot air for specific time periods effectively improved the heating uniformity of samples and raised the mortality of R. dominica in milled rice. Compared with the stationary conditions, conveyor movement, layer rearrangement, and sample mixing improved the hot air-assisted RF heating uniformity of the sample, raised pest mortality and reduced the thermal holding time after RF treatment required to achieve 100% pest mortality in milled rice. The findings of this study provide a valuable proof of concept for improving RF heating uniformity and optimizing parameters in RF disinfestation protocols for milled rice. Keywords: Heating uniformity, Milled rice, Mixing, Pest mortality, Radio frequency heating.

A 3D-printed oscillatory polymerase chain reaction system using a single heater

Nucleic acid amplification is a process that arises in all organisms. Polymerase chain reaction (PCR) is a standard laboratory nucleic acids amplification technology in vitro widely used in medical detection and biometric-related research. This device represents the first demonstration of 3D-printed oscillatory thermocycling within a portable PCR device. This study uses a single Peltier element to create the three temperature regions required for PCR. The overall control system uses an Arduino microcontroller with the advantages of easy development, abundant resources, and easy access to device software design. The sample-driving system integrated with the 3D printed object and the laser-cut acrylic component to achieve the linear reciprocating motion of the sample is conducive to the realisation of the portable design of the device. After system optimisation, the reaction tube moves from the denaturation zone to the aluminum block for cooling, and it moves to the groove of the denaturation zone from the annealing zone to accelerate the sample temperature rise. The time duration reduces from 180 s to 85 s to complete one thermal cycle. Combining the 5 mm instead of 3 mm thickness of the acrylic material and the configuration of the acrylic end exposed in the air creates a more significant temperature difference from 25 °C to 40 °C. Using this oscillatory PCR device, we successfully amplified a 219 bp PCR product of turmeric DNA after 30 thermal cycles within 50 min. The developed PCR device will cost less than $300 USD in our work. Compared with previous works, the cost of this research device is relatively low, and the total volume of the device is quite small. This work should be interesting to persons involved in diagnosing the infectious diseases of viruses and bacteria and identifying the fake healthy food in the low-cost bioreaction chambers in fields and remote areas.

Towards new generation of electrode-free conductive cement composites utilizing nano carbon black

Development of a scalable, low-cost conductive concrete with a long lifetime has the potential to evolve into a new solution for the next generation of floor heating systems. This work systematically investigates the performance of nano carbon black (NCB) cement composite as a viable candidate for floor heating. To this end, its conductivity and joule heating properties are adjusted by changing the weight percent of cheap and affordable NCB. The percolation transition zone is in the 10%-12.5% range for electrode-free specimens, where electrical resistivity sharply drops and the AC conductivity and joule heating significantly increase. Micro-model numerical simulation also confirms temperature rise in samples with NCB contents beyond the percolation threshold. Surprisingly, it is shown that the mechanical strength of the conductive composite developed in this work can remain at a satisfactory level.

Design of Saline Gel Coil for Inner Heating of Electrolyte Solution and Liquid Foods under Induced Electric Field.

As an emerging electrotechnology, induced electric field has attracted extensive attention in the development of innovative heat treatment equipment. In this study, a resistance heating unit based on induced electric field was built for inner heating of aqueous electrolyte solutions as well as liquid foods, such as vinegar. NaCl solutions and liquid foods with different conductivity were used to investigate the thermal effect and temperature rise of samples. Saline gel composed of 3% agar powder and 20% NaCl acted as a coil of conductor for inducing high-level output voltage. The utilization of the saline gel coil significantly improved the power conversion efficiency of the heating unit as well as the heating rate. The results revealed that duty cycle and applied frequency had immediate impact on the efficiency of inner heating. Additionally, the rate of temperature rise was proportional to the conductivity of the sample. The temperature of 200 mL NaCl solution (0.6%) increased from 25 °C to 100 °C in 3 min at 40% duty cycle and 60 kHz of applied frequency, and it was a circulating-flow process. The maximum temperature rise of black vinegar was 39.6 °C in 15 s at 60 kHz and 60% duty cycle, while that of white vinegar was 32.2 °C in 30 s under same conditions, whereas it was a continuous-flow process. This novel heating system has realized the inner heating of liquid samples.

Two-Step Dual-Wavelength Flash Raman Mapping Method for Measuring Thermophysical Properties of Supported Two-Dimensional Nanomaterials

To determine the thermophysical properties of supported two-dimensional nanomaterials, this paper developed a two-step dual-wavelength flash Raman mapping method. The thermal conductivity of the supported two-dimensional nanomaterial and the thermal contact conductance between the sample and the substrate can be determined by steady-state step. And then the thermal diffusivity of the sample can be characterized by the transient step. Two models are also proposed in this paper. When the substrate temperature rises obviously, a full model considered the substrate temperature distribution is used to decouple the thermal diffusivity, thermal conductivity, and the thermal contact conductance. When the maximum substrate temperature rise is less than 20% of the maximum sample temperature rise, the temperature distribution and variation of the substrate is assumed proportionate to the sample, and then a simplified model can be used to analyze the thermal diffusivity and the other parameters. For the thermal diffusivity, the system error caused by simplifying assumptions is less than 1%, when a dimensionless parameter related to the thermal contact conductance and the thermal conductivity less than 1 and the maximum temperature rise of the substrate less than 15% of that of the supported sample.

Microwave infrared ore sorting of screen rejected rocks based on their content of iron and copper sulfide in Sarcheshmeh copper complex, Iran, Kerman

ABSTRACT Feasibility study using microwave-IRT sorting technique for preconcentration of oversize screen rejected ores in primary mills of concentration units of Sarcheshmeh copper complex was investigated in this study. Three size fraction samples were exposed to microwave radiation followed by thermography imaging. Temperature rise of samples were compared with their element grades as provided by XRF analysis. Sortability performance index was computed for each size fraction and cumulative mass copper recovery was plotted for them. At first, the statistical method of cluster analysis (CA) was employed to study the thermographic data. The results of this analysis, in addition to the confirmation of previous findings on the relationship between temperature rise of the samples and their content of iron and copper sulfides showed that the ratio was proportional to the grade of iron and copper sulfide. Finally, it was shown that sorting this rejected stream using MW/IRT method is feasible and beneficial.

Simultaneous transmission and absorption photometry of carbon-black absorption from drop-cast particle-laden filters.

Simultaneous transmissivity and absorptivity measurements were carried out in the visible at a laser wavelength of 532 nm on drop-cast, carbon-black-laden filters under ambient (laboratory) conditions. The focus of this investigation was to establish the feasibility of this approach to estimate the mass absorption coefficient of the isolated particles and compare results to earlier work with the same carbon-black source. Transmissivity measurements were carried out with a laser probe beam positioned normal to the particle-laden filter surface. Absorptivity measurements were carried out using a laser-heating approach to record in time the sample temperature rise to steady-state and decay back to the ambient temperature. The sample temperature was recorded using a fine-wire thermocouple that was integrated into the transmission arrangement by placing the thermocouple flush with the filter back surface. The advantage of this approach is that the sample absorptivity can be determined directly (using laser heating) instead of resolving the difference between reflectivity (filter surface scattering) and transmissivity. The current approach also provides the filter optical characteristics, as well as an estimate of filter effects on the absorption coefficient due to particle absorption enhancement or shadowing. The approach may also be incorporated into other filter-based techniques, like the particle/soot absorption photometer, with the simple addition of a thermocouple to the commercial instrument. For this investigation, measurements were carried out with several blank uncoated quartz filters. A range of solution concentrations was prepared with a well-characterized carbon black in deionized water (i.e., a water-soluble carbonaceous material referred to as a surrogate black carbon or 'carbon black'). The solution was then drop cast using a calibrated syringe onto blank filters to vary particle loading. After evaporation of the water, the measurements were repeated with the coated filters. The measurement repeatability (95% confidence level) was better than 0.3 K for temperature and 3 × 10-5 mW for laser power. From the measurements with both the blank and coated filters, the absorption coefficient was determined for the isolated particles. The results were then compared with an earlier investigation by You et al. and Zangmeister and Radney, who used the same carbon-black material. The measurements were also compared with Lorenz-Mie computations for a polydispersion of spherical particles dispersed throughout a volume representative of the actual particles. The mass absorption coefficient for the polydispersion of carbon-black particles was estimated to be about 7.7 ± 1.4m2 g-1, which was consistent with the results expected for these carbon black particles.

Dual-Wavelength Laser Flash Raman Spectroscopy Method for In-Situ Measurements of the Thermal Diffusivity: Principle and Experimental Verification

This paper presents an in-situ, non-contact, non-destructive “dual-wavelength laser flash Raman spectroscopy method” for measuring the thermal diffusivity. In this method, a heating pulse is used to heat the sample and another pulsed laser with a different wavelength and negligible heating effect is used as a probe to measure the sample temperature changes during the heating and cooling periods from the Raman peak shifts. The sample temperature rise and fall curves are measured by changing the delay between the heating pulse and the probing pulse with the thermal diffusivity then characterized by fitting the temperature curves. The time delay between the heating and probing pulses can be precisely controlled with a minimum step of 100 ps. Hence, the temperature variation can be scanned with an ultra-high temporal resolution of up to 100 ps, which significantly improves the measurement accuracy of transient thermal parameters. The measurement accuracy of this method has been verified using a bulk material model and experiments. The measured thermal diffusivity of a silicon sample has been obtained to be 8.8×10-5 m2/s with a 3% difference between the measured value and the average result for bulk silicon in the literature which verifies the reliability and accuracy of this method.

Total inactivation of lipoxygenase in whole soya bean by pulsed light and the effect of pulsed light on the chemical properties of soya milk produced from the treated soya beans

AbstractThe inactivation of lipoxygenase (LOX) in the whole soya bean prevents lipid oxidation that produces an off‐flavour of soya food. The inactivation of lipoxygenase in the whole soya bean by pulsed light (PL) was examined with three distances (5, 7 and 9 cm) from the PL strobe and for different durations. Soya bean was treated with PL with and without ice surrounding the soya bean sample tray for limiting the rise in sample temperature. Results show that without ice surrounding the sample tray, the lowest LOX residual activity was 4.7%, 0.4% and 0.0% for 80‐s duration at 5 cm distance from the PL strobe, 110 s at 7 cm from the strobe and 150 s at 9 cm from the strobe, respectively; the soya bean temperature after treatment was 109.6, 116.3 and 114.8 °C, respectively. The instantaneous temperatures of the soya bean core measured during PL operating were above 100 °C. The lipoxygenase band was disappeared after longest PL treatments of each distance compared with the LOX band control as assessed by electrophoresis. The pulsed light had no negative effect on peroxide value of produced soya milk. However, PL reduced significantly the total solid amount and changed the colour of the produced soya milk. The residual activity with sample cooling by ice during treatment was 79.0%, 98.8% and 95.7%, with sample temperatures of 81.7, 91.2 and 66.9 °C, respectively. This study indicates that PL illumination could fully inactivate LOX in whole soya beans, with the photo‐thermal effect of PL as the main factor responsible for the inactivation of LOX.

Improving effect of boron carbide on the combustion and thermal oxidation characteristics of amorphous boron

Boron carbide (B4C) is one of the main products from the primary combustion of boron (B)-based propellants and has a significant influence on the secondary combustion of B. To systematically evaluate its effects on the secondary combustion of B, mixtures of B4C and B in different mass ratios were prepared. To study the ignition temperatures and combustion flames of the samples, a xenon lamp ignition experimental system and a flame shape test system were designed, respectively. A thermogravimetry–differential scanning calorimetry–Fourier transform infrared spectroscopy combined thermal analysis system was used to study the thermal oxidation characteristics and analyze the gaseous products of the samples. The results indicate that B4C reduces the heat absorption at the beginning of the ignition, but subsequently prevents the rapid rise of sample temperature. During the stable combustion stage, the maximum flame length under optical density 10−4 (OD4) filter was 20.4 mm, and the maximum flame length under 580 nm + OD4 filters (represents the combustion of B element) was 16.7 mm. The samples contained a small amount of HBO2 and H3BO3, which led to slight mass loss during the low temperature section of the thermal oxidation process. During the high temperature section, the oxidation of B and B4C caused considerable mass gain. The gaseous products of the thermal oxidation process include CO2, CO, and H2O. In general, the B content of 60% was the most beneficial to decrease the oxidation temperature, increase the combustion intensity, and improve the heat-releasing ability of the samples.

A new strategy for utilization of NIR from solar energy—Promotion effect generated from photothermal effect of Fe3O4@SiO2 for photocatalytic oxidation of NO

Photothermal effect was for the first time utilized to capture the energy from infrared light and to promote the photocatalytic oxidation activity of NO by a simply mechanical mixing of traditional photocatalysts and core-shell structured Fe3O4@SiO2. Fe3O4@SiO2 absorbed the infrared light, transferred it into thermal energy based on photothermal effect, which then accelerated the NO photocatalytic activity of traditional photocatalysts. This promotion effect led by the addition of Fe3O4@SiO2 was confirmed by several classical photocatalysts such as TiO2, g-C3N4, BiOI and CeO2. To quantitatively characterize the photothermal effect, thermo images were taken with a thermo imager to obtain the average temperature rise of samples under the illumination of simulated solar light. Specially, P25/Fe3O4@SiO2 was studied in depth for illustration of the promotion mechanism. Experimental results showed that with the contribution of SiO2 shell, the photocorrosion of Fe3O4 didn’t occur during photocatalytic oxidation process and the photothermal effect of Fe3O4 was maintained. The quantity of Fe3O4@SiO2 was a vital factor for promotion of photocatalytic activity and the optimum mass ratio of P25 and Fe3O4@SiO2 was 3–1. After 120min of illumination, the temperature of optimum P25/Fe3O4@SiO2 rose to 57.4°C from 25°C and its NO conversion capability showed an enhancement of 38.9% with the comparison to pure P25. The experimental results confirmed that the rise of temperature was attributed to the photothermal effect and its contribution was the same as the directly heating of photocatalysts. Furthermore, the enhancement of NO conversion capability around 30–40% was observed for the Fe3O4@SiO2 mixed anatase TiO2, g-C3N4, ZnO, BiOI and CeO2. In sum, we developed a new strategy for utilization of NIR light of solar energy to facilitate the photocatalytic reactions.

Electric field-assisted flash sintering of CaCu3Ti4O12: Microstructure characteristics and dielectric properties

The electric field-assisted flash sintering method recently introduced in the literature was here considered for producing high-quality CaCu3Ti4O12 electroceramics, from a powder originally synthesized by a Pechini-derived method and calcined at 800 °C for 2 h. The study included analyzing the dynamics of material shrinkage and densification. With increasing the electric field (E), three distinct regimes were observed: a conventional-like sintering behavior for E < 15 V/cm, followed by a region of accelerated (fast-dominated) sintering for 15 ≲ E < 30 V/cm, and then the flash-dominated regime, for E ≳ 30 V/cm, where sintering is not only accelerated but occurs suddenly. In consequence, sintering of the material under field input takes place at furnace temperatures sensibly lower, reaching a value as low as 750 °C for E = 60 V/cm versus 1050 °C in conventional processing. The probable physical mechanism behind each regime, including the role of the rise in sample temperature induced by the applied field (Joule heating), is also discussed. Finally, a correlation was found between the microstructure characteristics achieved during sintering and the dielectric response measured.

Softening process during reverse martensitic transformation in TiNi shape memory alloy

Strain variation in a Ti50Ni50 shape memory alloy subjected to 30 thermal cycles under a constant stress of 50 MPa through the temperature range of incomplete reverse martensitic transformation was studied. It is found that the rate of plastic strain accumulation depends on a fraction of the reverse transformation temperature range realized on heating of the Ti50Ni50 alloy during thermal cycling. The larger the fraction of the reverse transformation temperature range, the higher the rate of plastic strain accumulation was observed during thermal cycling. If the fraction of the reverse transformation temperature range is 0.75 or less, strain hardening results in a full arrest in the plastic strain accumulation at the stationary stage. Otherwise, the alloy accumulates the plastic strain with a constant rate at the stationary stage. It was shown that the strain hardening incompletely arrests the plastic strain accumulation at the last quarter of the reverse transformation temperature range due to the realization of a relaxation process on heating, which results in alloy softening. This is caused by an increase in dislocation mobility owing to a rise in sample temperature hence, this process is thermally activated. Completion of the softening process is controlled by the maximum temperature attained by heating during thermal cycling.

Effect of moisture on temperature rise of composite insulators operating in power system

The local heating phenomenon of composite insulator has drawn more and more attention gradually. From our analysis, the temperature rise of composite insulator is closely related to the moisture in atmospheric environment according to research results. Effect of moisture on the temperature rise of composite insulators is studied in this paper. The composite insulators, which have operated in power system for a long time and have been detected for local heating, and new insulator are taken as test samples. The temperature rise of operated composite insulators, which have been detected for local heating, increases with the rise of the relative humidity, while new insulator shows no temperature rise can be detected. The temperature rise of sample is not relevant to the core and the interface between core and housing material practically, but the high voltage end housing. The moisture content of the housing material is different at various relative humidity, and this leads to difference in dielectric loss, which is a significant source of local heating phenomenon. The difference of dielectric loss at different relative humidity leads to the temperature rise variation with the relative humidity.

Anomalous effects of ultradilute impurities on heat diffusion in liquids

We analyze the applicability of transient thermal lens (TL) z-scan technique as a sensitive tool to measure heat diffusivity of liquids. Suitable dyes at very low concentrations were added to the host liquid to enhance the TL effect through improved optical absorption. We investigate if these dye impurities, besides improving light absorption, have any effect on the thermal properties of the host liquid. We find that even a trace amount of impurity significantly alters the thermal properties of a solvent. Time-evolution of TL showed pronounced asymmetry about laser focus revealing anomalous behavior in thermal blooming of the laser beam. Heat transport was strongly dependent on the rise in sample temperature by light absorption. Important effects of nonlinear heat transport in time-resolved TL z-scan experiments were revealed.

Modeling the temperature rise in high-pressure torsion

Experiments and finite element modeling were used to estimate the temperature rise during high-pressure torsion. The results show the temperature rise is dependent upon the material strength, the rotation rate, the sample radius, the heat capacity and the volume of the anvils. A general relationship is derived which predicts the temperature rise in samples of different geometries processed using different anvil sizes. A simplified version of the equation is presented for general use.

Analysis of the electrothermal technique for thermal property characterization of thin fibers

The transient electrothermal technique has been developed to measure the thermal conductivity and thermal diffusivity of electrically conductive or non-conductive nano-to-microscale fibers. In this work, a full theoretical model is developed in detail including the effects of radiation heat loss and non-constant heating as a result of sample temperature rise during measurement, and is compared to the more commonly used reduced model, which neglects these effects. Non-dimensional parameters are derived representing radiation heat loss and non-constant heating to identify the true parameter dependences on these effects. A numerical model is used to perform parametric analyses on the experimental setup providing results that were fitted with the full and reduced models to find thermal conductivity and thermal diffusivity. Additionally, the numerical model was used to investigate nonlinear radiation heat losses and spatially non-uniform heating effects resulting from uneven coating of the conductive layer on electrically non-conductive samples. As a result, these influences are shown to require careful consideration in the application of this technique. A clear linear relationship was found between the non-dimensional parameters and measurement error, which provides a measure for the proper estimation of systematic error induced by these effects. Using the reduced model for data reduction results in measurement percentage error equal to ten times the radiation and non-constant heating dimensionless parameters under the assumption of linear radiation heat losses (small sample temperature rise compared to ambient temperature).

Study on Characteristics of Mn-Zn Ferrite Prepared by Microwave Sintering of Powder Compacts

The microwave absorption properties and the densification of powder compacts of Mn-Zn ferrite heated by Microwave with frequency of 2.45 GHz are studied,the microwave heating mechanism of Mn-Zn soft ferrite powder compacts is discussed,and the morphology of sintered samples are observed using scanning electron microscopy(SEM). The results show that:Microwave heating of Mn-Zn ferrite powder compacts in the initial(heating temperature lower than 500 ℃),sample temperature rise rate is faster,the average is 15 ℃ /min,the sample absorbing performance is better. When the sample temperature is higher than 500 ℃ the heating rate gradually decreased,temperature reached 800 ℃ the heating rate more slowly,then must increase the microwave power,the temperature of the sample will continue to rise. Sample temperature above 1 400 ℃,material will occur "runaway". The sintering temperature is the main factor of affecting the sintering density. The sintering density of powder compacts increased obviously with the increased of sintering temperature,the density increases from 1 250 ℃'s 4.20 g/cm3to 1 400 ℃'s 4.93 g/cm3. Using SEM to observe the morphology of sintered samples,the results show that the morphology of Mn-Zn ferrite powder compact microwave sintered at 1 400 ℃ is uniform,Mn-Zn ferrite in microwave field can sintered rapid densification.

Temperature rise during differential speed rolling

Abstract The present work investigated the temperature rise of an interstitial-free steel sample during differential speed rolling as functions of the height reduction and roll speed ratio. The temperature rise increased with increasing either height reduction or roll speed ratio, approaching a maximum value of 100 °C under height reduction of 40% and roll speed ratio of 1:4. In addition, the temperature rise of the sample during deformation was predicted by the concept of the energy-based state equation.