Experimental Temperature Research Articles

Preparation and study of B and P doped SiNTs

The unique properties of silicon nanotubes (SiNTs) are expected to provide them with a very wide range of application potential in nanoelectronic devices, lithium-ion batteries, sensors, field-effect transistors, magnetic nanodevices, hydrogen reservoirs, optoelectronic devices, field emission display devices, and quantum computers, and they are a new one-dimensional nanomaterial with a wide range of applications in the future. Although researchers have already prepared SiNTs in the laboratory, there are not many research reports on SiNTs, especially the preparation of B and P doped SiNTs and analysis based on spectroscopic techniques. Our research group used silicon sources (SiO2 and Si) that had not been previously reported or catalyzed by the rare earth element lanthanum (La). The optimal experimental conditions for the preparation of SiNTs, as well as the doping preparation and study of B and P, were explored by thermal evaporation. Finally, SEM, Raman spectroscopy, selected area electron diffraction, HRTEM, XRD, PL spectroscopy, and other characterization methods were performed on the experimental samples. The experimental results show that 1280 °C was the best experimental temperature for the preparation of SiNTs. Under experimental conditions of 1280 °C, doping of B favored the synthesis of silicon nanowires and SiNTs, and the number of products generated was from least to most: no added B2O3 < 0.1 g B2O3 < 0.2 g B2O3 < 0.3 g B2O3 < 0.4 g B2O3. Under the experimental conditions of 1280 °C, when the amount of doped B2O3 is large (2.2 g), a “needle” structure product is generated. Under experimental conditions of 1400 °C, when the ratio of doped P to the original material is 1:9, a new material that has not been previously reported is generated. Through relevant research and the findings of this paper, it is hoped that it can be helpful for the future research and application of SiNTs.

Possible Uses of Decommissioned Coke Batteries

Since the 80s of the 20th century, as a result of the reduction in demand for coke, economic crises and the availability of coking coal, the operations of coke plants in Europe have been ending. Furthermore, the pressure for using renewable energy sources continues to increase, including the production of fuels. In most cases, the current solution is to add biocomponents to fuels produced in the classical way from oil. There are considerations about reusing these coke batteries, this time for the production of liquid fuels. Therefore, this work is devoted to the processing of biomaterials mixed with brown coal by the pyrolytic process. Extracted rapeseed meal, sunflower seed husks and dry distillery grain with solubles (DDGS) were selected as biomaterials. They are waste material from various productions, but these materials also show good energy potential. The brown coal came from the ČSA quarry, which is characterized by a low content of sulfur and ash and also improves the properties of liquid pyrolysis products, because it reduces polarity of organic phase, which enables easier separation of the aqueous and liquid phases of the product. Pyrolysis experiments were carried out in two different pyrolysis devices - i) in a micropyrolysis unit (sample loading: in the order of mg, heating rate: 100 °C s-1, fast removal of pyrolysis products); ii) in the pilot unit (sample weight: approx. 10 kg, heating rate: 5.2 °C min-1 and slower removal of pyrolysis products, cuboid shape of the pyrolysis retort simulating a coke oven battery). On the basis of mass balances and characteristics of micropyrolysis products, the pyrolysis temperature for pilot experiments was set at 650 °C. Behind the pyrolysis retort of the pilot unit, a thermic-catalytic reactor (catalyst: sulfurized aluminosilicate based on Ni-W) was connected in order to improve the quality of volatile pyrolysis products. The highest yields of organic phases of liquid products came from co-pyrolysis of coal and DDGS and coal with rapeseed meal. However, the characteristics of organic phases determined as the most advantageous material for the pyrolytic processing the rapeseed meal (specifically a higher proportion of aliphatic and aromatic hydrocarbons, a lower proportion of hydrocarbons with heteroatoms and a higher proportion of light fractions). The most beneficial pyrolysis mixture contained 35 % of rapeseed meal and the temperature in the catalytic part of the thermic-catalytic reactor was 300 °C.

Study and Analysis of the Drying Kinetics of Jalapeño Pepper in a Convective Dryer

The high moisture content in jalapeno peppers (Capsicum annuum L.) can cause the growth and reproduction of microorganisms, making processing and long-term storage difficult. The objective of the research is to evaluate the kinetics of jalapeño pepper drying in a convective dryer. for this reason, the drying of the jalapeño pepper was carried out in a dryer with hot air at temperatures of 40, 50 and 70°C; obtaining the drying kinetic curves, the drying time that was 18, 31 and 41 respectively; the effective diffusivity was 2.924E-10m2.s-1 for the temperature of 40°C, 7.521 E-9 m2.s-1 for 50°C and 1.307 E-9 m2.s-1 for 70°C; the degree of correlation (R2) between the moisture content and the drying time was 0.994 at 70°C with a root mean square error (RMSE) of 0.0429, R2 of 0.990 at 50°C with a RMSE of 0.0216 and R2 of 0.993 at 40°C with an RMSE of 0.0162, so it is concluded that the criteria for a good adjustment of the drying model between the experimental temperature, as well as between the humidity rate and the drying time are met.

Microwave heating of thin rubbers based on single-ridged waveguide

Microwave heating has been gradually applied to rubber vulcanization. However, it is difficult to process thin rubber using microwaves because of low electromagnetic power loss and rapid heat dissipation. Therefore, in this study, a single-ridged waveguide was designed to efficiently heat thin rubber. First, a single-ridged waveguide was designed and optimized to ensure good wave transmission and a strong electric field, and its energy efficiency was approximately 331.9 times greater than that of multi-mode cavity and 77.9 times greater than that of WR340. Then, a multiphysics model coupling the electromagnetic field and heat transfer in a solid was built to investigate the heating performance. The results of additional experiments showed that the experimental and simulated temperature distributions were consistent. Finally, the effects of the working state, offset of the short-circuited surface, the rubber's thickness and permittivity on the heating performance were investigated, and the vulcanization analyses were discussed.

Investigation of structural, topological, and electrical properties of scheelite strontium molybdate for electronic devices

This article describes the synthesis (solid-state reaction) and characterizations of a scheelite strontium molybdate. The consistency of lattice parameters by N-TREOR09 and the Le-Bail Rietveld refinement method supports the tetragonal crystal system. The spectrum of the pair distribution function (PDF) depicts the orientations of atoms within a tetragonal symmetry. The Williamson-Hall plot examines the average crystallite size (86 nm) and micro-lattice strain (0.00091). The scanning electron microscopic image, energy dispersive X-ray (EDX) spectra, and elemental mapping confirm the uniform and isotropic characteristics of the synthesized material, purity and compactness, and topographic roughness according to ISO25178 standards. The investigation of dielectric, impedance, and conductivity spectra confirms the presence of Maxwell-Wagner dielectric dispersion, relaxation, and influential transport phenomena across a broad spectrum of experimental frequencies (ranging from 1 kHz to 1 MHz) and temperatures (from 25 °C to 500 °C). The observed temperature-dependent resistance characteristics validate that the prepared material is well-suited for applications involving PTC thermistors, sensors, and other related devices. The scaling properties of the modulus data provide evidence for a non-Debye relaxation mechanism. The values of the varistor constant, β1, β2, and β3, which are 1.414, 2.362, and 9.654, respectively, indicate the existence of Ohmic conduction, trap-limited space charge limited conduction (SCLC), and trap-filled SCLC mechanisms suitable for electronic devices.

An empirical firebrand pile heat flux model

Firebrand exposure has been identified as a leading cause of structure losses during wildfires. However, only a limited number of studies have attempted to quantify the incident firebrand heat flux to a target substrate surface. In this study, a bench-scale wind tunnel retrofitted with an IR thermal imaging system was used to generate high-resolution temperature data for the back surface of a thin, non-combustible insulation board exposed to a glowing firebrand pile at 0.9–2.7 m s−1 air flow velocities and 0.06 and 0.16 g cm−2 firebrand coverage densities. An inverse heat flux modelling technique utilizing a solid-phase pyrolysis solver, ThermaKin, was employed to determine transient firebrand pile heat flux profiles underneath and directly in front of a glowing firebrand pile. The inverse modelling technique used both the experimental back surface temperature data and the insulation's thermophysical properties. Average incident firebrand pile heat flux values obtained for all testing conditions ranged between 28 and 80 kW m−2. For the first time, an empirical model capturing the firebrand pile incident heat flux dependence on time, air flow velocity and firebrand coverage density was developed.

Combinatorial ratiometric strategy for continuously highly sensitive thermometry in transparent germanate glass-ceramic containing upconversion nanocrystals

Ratiometric luminescence thermometry is a promising method for non-contact and non-invasive thermometry. Maintaining consistently high temperature sensitivity over a wide temperature range is still a challenge for many ratiometric luminescence thermometers. Here, we have developed a novel transparent germanate glass-ceramic containing NaY3F10:Yb3+/Tm3+/Er3+ nanocrystals. The crystalline content of which remained highly stable during a tunable heat treatment process. Compared with glass, the upconversion luminescence of the glass-ceramic, which originated from the thermally and non-thermally coupled energy levels of Tm3+ and Er3+, was significantly enhanced. Using the temperature-dependent fluorescence intensity ratios of selected upconversion emissions, a ratiometric thermometry scheme with high temperature sensitivity was constructed. The relative sensitivity maintained at a high level (1.30–2.61 %K−1) over the experimental temperature range (323–573 K). The best resolution and repeatability were ±0.13 K and 99.6%, respectively. This transparent glass-ceramic is an excellent candidate for ratiometric thermometry, which is expected to be applied to fibre-optic thermometers.

Characterization of Asphaltene Deposition Behavior in Diluted Heavy Oil under High-Pressure Conditions

Some oil wells in the Tahe oilfield have been reported to produce extremely heavy oil due to asphaltene deposition. To enhance the flow of crude oil through the wellbore, engineers adopted the use of light oil from nearby wells to dissolve the heavy crude in the wells’ sections to maximize recovery from the Tahe oilfield. However, this mixing has led to the problem of accelerated asphaltene deposition, which often blocks the wellbore in the process. In this research, the factors that influence the stability of diluted heavy oil, temperature, and mixing ratio on asphaltene deposition characteristics under high pressure are studied using a high-temperature and high-pressure crude oil flow property experimental device based on the differential pressure method. The results under high pressure show that the initial deposition pressure of asphaltene decreases as the experimental temperature increases. With an increase in the mixing light oil ratio, the initial deposition pressure of diluted heavy oil increases, and the deposition trend of asphaltene strengthens. The asphaltene accumulation and deposition will be aggravated by filling quartz sand and pipe diameter changes. The research here is helpful to understand the deposition characteristics of asphaltene during the production of diluted heavy oil. It offers significant guidance in the prevention and control of asphaltene precipitation in heavy oil wells.

High-temperature and interfacial oxidation of MAX phase-reinforced composite coatings deposited by laser cladding on Zr alloy substrates

MAX phase-reinforced composite coatings were successfully prepared by laser cladding in-situ reaction using TiAl–TiC–Al powder preset on R60702 zirconium alloy surface. The behavior of composite coatings under high-temperature oxidation and interfacial oxidation was investigated. Differential thermogravimetry (DTG) oxidation weight gain curves demonstrated that high-temperature oxidation resistance of composite coating was better than that of Zr alloy. Oxide phase of composite coating mainly contained TiO2 and small amount of Al2O3. Oxidation characteristics of carbides (TiC and Ti2AlC) and TiAl intermetallic compounds revealed that oxidation rates of carbides were higher than those of TiAl intermetallic compounds. In addition, reasons for their different diffusion or oxidation rates were also discussed from the perspective of stability of original microstructure before and after oxidation. At the highest experimental temperature (1100 °C), oxide film thickness of composite coating (20 μm) was smaller than that of Zr alloy (550 μm). Interfacial oxidation behavior indicated that there was bimetallic galvanic corrosion effect between composite coating and Zr alloy, which is related to high electronic energy level of Zr from the perspective of quantum mechanics.

Method for Obtaining Isothermal Diagrams of the Liquid - Vapor Equilibrium for the System as Dimethyl Zinc - Dimethyl Telluride

According to the obtained experimental temperature dependences of the saturated vapor pressure on dimethylzinc – dimethyltelluride solutions with dimethylzinc content of 50.0 and 70.32 mol. %, isothermal sections (280, 290, 300, 310, and 320 K) were made. For the dimethylzinc – dimethyltelluride system based on a limited set of experimental data for the “liquid-vapor” equilibrium, the vapor composition was calculated according to the Duhem – Margules equation, as well as the partial pressures and the distribution coefficient.

Avoiding false runaway prediction by properly describing axial conductive heat transfer in a low dt/dp industrial-scale packed bed reactor

The impact of axial conductive heat transfer on the simulation and prediction of hot spots and, more particularly, runaway, within an industrial-scale wall-cooled packed-bed reactor with low tube-to-particle diameter ratio (dt/dp ∼ 3) has been assessed in this work. To this purpose, the effective axial conductivity (keff,z) was first determined from adiabatic experiments in a bench-scale packed bed in the absence of reaction. Next, non-adiabatic and non-isothermal bench-scale and industrial-scale packed bed experimental data were used in the assessment of the impact of axial heat conduction on the prediction of the temperature profile. The so-called Pseudo-local Internal Heat Transfer Approach (PL-IHTA) was used for the adequate description of the radial temperature gradients. Finally, an industrial-scale wall-cooled packed bed reactor for the highly exothermic catalytic oxidative dehydrogenation of ethane was modeled to assess the impact of the axial thermal conductivity on temperature profile simulations. When disregarding axial heat conduction or adopting literature-based values for keff,z, determined from either experiments at low dt/dp ratios (<8) and Rep ≤ 1000 or high dt/dp ratios (>8) and Rep ≤ 700 at a wide panel of operating configurations, runaway is simulated at conditions where it has not been observed experimentally or a negligible hot-spot prediction is obtained. When considering the keff,z determined for the specific reactor configuration in this work, hot spots are predicted at Rep of 700 and 1400, but no runaway. The discrepancies between experimental findings and temperature profiles simulated using literature-based values for keff,z indicate the need for a specific determination of keff,z in packed bed reactors with low dt/dp ratio to more accurately predict hot spots, resulting in more reliable reactor design and operation.

Data processing for simultaneous inversion of emissivity and temperature using improved CABCSMA and target-to-best DE algorithms in multispectral radiation thermometry (MRT).

In this paper, what we believe to be, a new combined algorithm of artificial bee colony and slime mould algorithm (CABCSMA) and a differential evolution (DE) algorithm using target-to-best variation strategy are proposed to process the data based on Planck's radiation law and the mathematical model of reference temperature. The material model with 6 different emissivity trends is simulated. Simulation results show that the average relative error of CABCSMA algorithm is less than 0.68%, and the average calculation time is 0.44s. The average relative error of DE algorithm is less than 0.43%, and the average calculation time is only 0.06s. The two algorithms were applied to the temperature test of silicon carbide sample, tungsten material and rocket engine nozzle. The experimental results show that the relative error of silicon carbide experimental temperature is less than 0.41% and 0.28%, and the relative error of tungsten material experimental temperature is less than 0.31% and 0.3%. The relative errors of rocket engine nozzle temperature experiments are within 0.68% and 0.52%, respectively. The results show that these two algorithms are expected to be applied in practical measurement scenarios.

Solubility determination and thermodynamic model analysis of nefopam hydrochloride in eight plain solvents and three binary solvents from 273.15 K to 323.15 K

Nefopam hydrochloride (NPH) is a non-narcotic analgesic with antipyretic, analgesic, and muscle relaxant effects. Solubility is an important molecular property that can inform the crystallization and purification of drugs. In the present study, NPH solubility was measured in eight plain solvents and three binary solvents at 273.15 K-323.15 K. Results showed that in the plain solvents, NPH had the greatest solubility in methanol and the least in acetone. The solubility in the solvent system of methanol + acetone and ethanol + acetone becomes greater with the increase of the molar fraction of the positive solvent, while it becomes greatest in the system of water + acetone when the molar fraction of the positive solvent is 0.8 and at molar fractions>0.8 the solubility begins to decrease, which may be owing to the existence of the phenomenon of co-solubility. NPH solubility in plain solvents and binary solvents is positively correlated with temperature. By XRD and TG-DSC, the crystal structure of NPH in solvent did not change and the weight loss and melting temperatures were 500.49 K and 518.34 K respectively, which were much higher than the experimental temperatures. Selection of Hansen solubility parameter to predict the solubility effect of NPH in different solvents. The analysis was carried out using five thermodynamic models, ranging from Modified Apelblat model, Buchowski-Ksiazaczak λh model, CNIBS/R-K model, Jouyban-Acree model and SUN model, to fit the solubility data, out of which Modified Apelblat model and CNIBS/R-K model had more accurate prediction results.

Teosinte populations exhibit weak local adaptation to their rhizosphere biota despite strong effects of biota source on teosinte fitness and traits.

While biotic interactions often impose selection, species and popula- tions vary in whether they are locally adapted to biotic interactions. Evo- lutionary theory predicts that environmental conditions drive this variable local adaptation by altering the fitness impacts of species interactions. To investigate the influence of an environmental gradient on adaptation be- tween a plant and its associated rhizosphere biota, we cross-combined teosinte (Zea mays ssp. mexicana) and rhizosphere biota collected across a gradient of decreasing temperature, precipitation, and nutrients in a greenhouse common garden experiment. We measured both fitness and phenotypes expected to be influenced by biota, including concentrations of nutrients in leaves. Independent, main effects of teosinte and biota source explained most variation in teosinte fitness and traits. For example, biota from warmer sites provided population-independent fitness benefits across teosinte hosts. Effects of biota that depended on teosinte genotype were often not specific to their local hosts, and most traits had similar relation- ships to fitness across biota treatments. However, we found weak patterns of local adaptation between teosinte and biota from colder sites, suggest- ing environmental gradients may alter the importance of local adaptation in teosinte-biota interactions, as evolutionary theory predicts.

Tribo-Informatics Approach to Investigate the Friction and Wear of Bushings in the Variable Stator Vane System

Abstract Determining the friction and wear behaviors of aero-engine key components under realistic conditions is important to improve their long-term reliability and service life. In this paper, the friction and wear behaviors of different bushing materials in the variable stator vane (VSV) system were investigated through the basic pin-on-disc test and actual shaft-bushing test. Different machine learning (ML) models were established based on the experimental information to predict the coefficient of friction (COF) and wear-rate. The results indicated that there is a significant temperature warning line for the wear amount of the polyimide material, while the high-temperature alloy material exhibited stable tribological performance under experimental load and temperature conditions. ML analysis indicated that the extreme gradient boosting (XGB) outperformed other ML algorithms in predicting the COF (R2 value = 0.956), while the kernel ridge regression (KRR) produced the best performance for predicting the wear-rate (R2 value = 0.997). The tribo-informatics research for bushings in the VSV system can accelerate the structural optimization and material selection and support the evaluation of new structures and materials.

Asymptotic and approximate solutions for piloted ignition of thermally thick solids under power-law heat flux

New asymptotic solutions are established in this work to describe the piloted ignition behaviors of thermally thick solids exposed to power-law thermal radiation accounting for convective, radiative and their combined heat loss effects. In all scenarios, the derived surface temperature and ignition time correlations share a similar form. The ignition time to the power of −0.5 linearly depends on the transient radiation. The asymptotic solutions are validated by comparison with numerical solutions and compared for accuracy with previous approximate correlations. Moreover, according to the surface temperature history, an asymptotic mass flux solution is attained. Accuracy of all solutions are verified by numerical and experimental results where vertical PMMA was heated by five power-law heat fluxes. The predicted surface temperatures fit the numerical and experimental curves well if the ignitor is located at the top sample holder. However, for center ignitor the developed model overestimates experimental surface temperatures at ignition time due to the neglected pyrolysis caused by increased thermal penetration effects. Effects of ignitor location are important for low heat fluxes. The asymptotic mass loss rates agree well with numerical and experiential results. Both critical temperature and critical mass loss rate are used to estimate ignition times, and good agreement is found except for the experimental cases of top ignitor.

Effects of microplastics exposure on soil inorganic nitrogen: A comprehensive synthesis

Microplastics, a growing environmental concern, impact soil inorganic nitrogen (N) transformation, specifically affecting water-extractable nitrate N (NO3−−N) and ammonium N (NH4+−N). However, inconsistencies among relevant findings necessitate a systematic analysis. Accordingly, the present meta-analysis addresses these discrepancies by evaluating the effects of microplastics on soil inorganic N and identifying key influencing factors. Our meta-analysis of 216 paired observations from 47 studies demonstrates microplastics exposure causes an overall significant reduction of 7.89% in soil NO3−−N concentration, but has no significant impact on NH4+−N concentration. Subgroup analysis further revealed effects of microplastics on soil inorganic N were modulated by microplastics characteristics, experimental conditions (exposure time, experimental temperature, plant effects), and soil properties (soil texture, initial soil pH, initial soil organic carbon, soil total N concentration). We found that microplastics exposure above 27 ℃ enhances soil NO3−−N concentration, a finding linked to specific soil properties and conditions, underscoring the impacts of global warming. Importantly, the microplastics polymer type was the most influential predictor of effects on soil NO3−−N concentration, while soil NH4+−N concentration was primarily affected by soil texture and microplastics type. These findings illuminate the complex effects of microplastics on soil inorganic N, informing soil management amid increasing microplastics pollution.

Comparisons of pulsed ultrasound-assisted and hot-acid extraction methods for pectin extraction under dual acid mixtures from onion (Allium cepa L.) waste.

The aim of this study is to compare the physicochemical properties and yields of pectins extracted from onion waste under hot acid (HAE) and pulsed ultrasound-assisted extraction (PUAE) methods using different organic-inorganic acids, their mixtures, and pure water. The extraction temperature for experiments carried out under HAE was kept at 90°C for 90 min, whereas PUAE experiments were accomplished at RT in 15 min. In general, HAE gave better pectin yields compared with PUAE due to the significance of the increasing extraction temperature for the release of pectin from the plant matrix. While the maximum pectin yield from onion waste was 16.22% for HAE, the highest yield for PUAE was 9.83%. PUAE provides less time- and energy-consuming extraction of pectin within 15 min and thus seems to be more economic compared with the HAE. According to the physicochemical properties (equivalent weight (EW), degree of esterification (DE), methoxyl (MeO), and galacturonic acid (Gal-A) contents) of obtained pectins, extracted pectins were mostly high methoxy pectin. While the DE and MeO values of pectins extracted in organic acid conditions under HAE were higher, these values were found to be higher for pectins extracted in inorganic acids under PUAE. For acid mixtures, the DE and MeO values of pectins under HAE were mostly found to be lower than those under PUAE. Sequential PUAE and HAE methods for the extraction of pectin from onion waste were also found to be useful in terms of obtaining higher yields and better physicochemical properties. The highest pectin yield was 20.32% for the sequential PUAE and HAE methods. FT-IR analyses of the extracted pectins by both HAE and PUAE methods showed similar vibration bands compared with those of commercial citrus pectin.

Temperature-dependent modulation of odor-dependent behavior in three drosophilid fly species of differing thermal preference

Rapid and ongoing climate change increases global temperature, impacts feeding, and reproduction in insects. The olfaction plays an important underlying role in these behaviors in most insect species. Here, we investigated how changing temperatures affect odor detection and ensuing behavior in three drosophilid flies: Drosophila novamexicana, D. virilis and D. ezoana, species adapted to life in desert, global, and subarctic climates, respectively. Using a series of thermal preference assays, we confirmed that the three species indeed exhibit distinct temperature preferences. Next, using single sensillum recording technique, we classified olfactory sensory neurons (OSNs) present in basiconic sensilla on the antenna of the three species and thereby identified ligands for each OSN type. In a series of trap assays we proceeded to establish the behavioral valence of the best ligands and chose guaiacol, methyl salicylate and isopropyl benzoate as representatives of a repellent, attractant and neutral odor. Next, we assessed the behavioral valence of these three odors in all three species across a thermal range (10-35 °C), with flies reared at 18 °C and 25 °C. We found that both developmental and experimental temperatures affected the behavioral performance of the flies. Our study thus reveals temperature-dependent changes in odor-guided behavior in drosophilid flies.

The influence of coefficient of friction in thermal prediction of refill friction stir spot welding process of AA7075‐T6

AbstractNumerical modelling of refill friction stir spot welding helps in the deep investigation of physics involved in the joining process. The current study investigates four variants of contact models and their influence on thermal prediction in the process. The contact models with constant shear and coulomb friction coefficients and temperature‐dependent shear and coulomb friction coefficients were used in the numerical models to investigate the influence of friction coefficients in the prediction of thermal cycles in refill friction stir spot welding. The results from the numerical model are compared and validated with the experimental results from a previous study. The contact model with temperature‐dependent coulomb friction coefficient was concluded to be more reliable when compared to the other three contact models. The temperature for this contact model at the centre of the weld is 505 °C, which differs from the temperature recorded in the experiment by 2 %. The peak temperatures of numerical models with constant coulomb and shear friction coefficients differ from the experimental temperature at the weld centre by 5.17 % and 16.8 % respectively.