Thermal Volume Research Articles

Constructing Fe2O3 particles uniformly grown on graphene oxide as additives for ethylene vinyl acetate copolymer thermal stability, thermal conductivity and anti‐static performance enhancement

AbstractEthylene‐vinyl acetate copolymer (EVA) has been widely used for packaging materials for decades. However, EVA was highly restricted due to the poor thermal stability and anti‐static performance. For enhancing thermal stability and anti‐static performances, a large number of additives were added to EVA, which seriously prejudice the processability and mechanical properties of the polymer. To address this problem, N‐doped reduced graphene oxide@Fe2O3 (RGF) was constructed as a heat and electronic conduction actor in EVA matrix in this work. As as‐prepared RGF composites shown, Fe2O3 particles well dispersed on the surface of RGO sheets, forming a point‐plane three‐dimensional structure. Therefore, the thermal conductivity and volume resistivity of the EVA composites reached 0.58 W/mK and 1.7 × 1010 ohm∙cm at 1.0 wt.% of RGF addition, which shows 284% folds increasement and 7 orders of magnitude decrement than neat EVA. Moreover, the storage modulus and thermal stability of EVA composites at 180°C were also improved. In sum, all those enhancements were attributed to the Fe2O3 particles well dispersed on RGO sheets, and amino groups from RGF provided mass of hydrogen bonds with EVA chains which provide more sites and path for heat and electronic conduction. In this work, RGF composites and its synthesis strategy show potential promising in the highly effective thermal and electrical exchange materials.

Thermosolutal Convection of Natural and Anti-Natural Solutions Through an Angled Cavity Under Cross Gradients in Temperature and Concentration

In the current study, cross-temperature and concentration gradients are used to model the in a binary fluid contained in an angled square cavity. Using a method, the , , and conservation equations were numerically solved. The inclined cavity under equal solutal buoyancy and thermal forces was the subject of the study . Since the horizontal components of the thermal and singular volume forces were equal but opposed to one another, an equilibrium solution for this situation that corresponds to the rest state of the immobile fluid is feasible. However, this equilibrium solution becomes unstable above a specific critical value of the , leading to vertical density stratification inside the enclosure. The results are shown using the and as well as the and for the flow intensity. The existence of the commencement of convection is demonstrated in this work, and both natural and anti-natural flow solutions are obtained. Subcritical convection has also been seen for the natural solution when the is more or less than unity. For the start of supercritical and subcritical convection, the number's critical values are identified. As the climbed, so did the flow's intensity and the rates at which heat and mass were transferred. Reducing flow intensity and accelerating mass transfer are the results of raising the . Different flow patterns are shown for an aspect ratio of 4, and the existence interval of the oscillatory solutions is calculated.

Revealing the promising near-room-temperature thermoelectric performance in Ag2Se single crystals

With high carrier mobility and intrinsic low lattice thermal conductivity, Ag2Se compounds have attracted increasing attention for thermoelectric application near room temperature. Due to its phase transition at ∼406 K and resulting thermal volume expansion, the growth and thermoelectric properties of large-sized Ag2Se single crystals have seldom been reported so far. In this work, the vertical Bridgeman method was used for growing bulk Ag2Se single crystal, with an orientation preference along low-symmetric (201) plane. The Hall mobility as high as 2 000 cm2/(V·s) and weak electron-phonon coupling contributes to a high electronic quality BE of ∼7.0 in near-room-temperature β-Ag2Se single crystals, which is superior to the high-temperature phase α-Ag2Se. The observed low lattice thermal conductivity of 0.8 W/(m·K) at 300 K is due to the low group speeds and strong anharmonicity. A promising peak zT of 0.66 at 375 K and an average zT of 0.65 at 300–375 K were realized in β-Ag2Se crystals. The low Vickers hardness and good ductile properties were confirmed by experiment and theoretical analysis. This work not only synthesized large-sized and highly-orientated Ag2Se crystals, but also revealed its great potential of thermoelectric performance and mechanical properties for various applications near room temperature.

Inverse Identification and Design of Thermal Parameters of Woven Composites through a Particle Swarm Optimization Method

Designing thermal conductivity efficiently is one of the most important study fields for taking the advantages of woven composites. This paper presents an inverse method for the thermal conductivity design of woven composite materials. Based on the multi-scale structure characteristics of woven composites, a multi-scale model of inversing heat conduction coefficient of fibers is established, including a macroscale composite model, mesoscale fiber yarn model, microscale fiber and matrix model. In order to improve computational efficiency, the particle swarm optimization (PSO) algorithm and locally exact homogenization theory (LEHT) are utilized. LEHT is an efficient analytical method for heat conduction analysis. It does not require meshing and preprocessing but obtains analytical expressions of internal temperature and heat flow of materials by solving heat differential equations and combined with Fourier's formula, relevant thermal conductivity parameters can be obtained. The proposed method is based on the idea of optimum design ideology of material parameters from top to bottom. The optimized parameters of components need to be designed hierarchically, including: (1) combing theoretical model with the particle swarm optimization algorithm at the macroscale to inverse parameters of yarn; (2) combining LEHT with the particle swarm optimization algorithm at the mesoscale to inverse original fiber parameters. To identify the validation of the proposed method, the present results are compared with given definite value, which can be seen that they have a good agreement with errors less than 1%. The proposed optimization method could effectively design thermal conductivity parameters and volume fraction for all components of woven composites.

Numerical simulation on energy transfer enhancement of a Williamson ferrofluid subjected to thermal radiation and a magnetic field using hybrid ultrafine particles

In this numerical investigation, completely developed laminar convective heat transfer characteristics of a Williamson hybrid ferronanofluid over a cylindrical surface are reported. This new model in 2D is engaged to examine the effects of the magnetic field, thermal radiation factor, volume fraction of ultrafine particles, and Weissenberg number with the help of the Keller box method. The numerical calculations are implemented at a magnetic parameter range of 0.4 to 0.8, volume fraction range of 0.0 to 0.1, and a Weissenberg number range of 0.1 to 0.8. The numerical outcomes concluded that the velocity increases when the thermal radiation parameter and the volume fraction of a nanoparticle are increased, but inverse impacts are obtained for the magnetic parameter and the Weissenberg number. The rate of energy transport increases with increasing thermal radiation and volume fraction, while it declines with increasing the magnetic parameter and Weissenberg number. The drag force shows a positive relationship with the thermal radiation parameter and has an opposite relationship with the Weissenberg number and the magnetic parameter. Furthermore, even when the magnetic field, thermal radiation, volume fraction, and Weissenberg number are all present, the heat transfer rate of Williamson hybrid ferronanofluid is greater than that of mono Williamson ferronanofluid.

Nonlinear Electro-Thermo-Torsional Buckling Analysis of Stiffened Functionally Graded Graphene-Reinforced Composite Laminated Toroidal Shell Segments

A new design of functionally graded graphene-reinforced composite laminated (FG-GRCL) toroidal shell segments in the thermal environment with a piezoelectric layer attached to the surface of the shells is presented in this paper. The piezoelectric FG-GRCL toroidal shell segments are reinforced by a FG-GRCL stringer and/or ring stiffener system. The nonlinear electro-thermo-torsional buckling and postbuckling of the shells are analyzed considering the geometrical nonlinearities described by von Kármán in the framework of the classical Donnell thin shell theory. Airy’s stress function and Galerkin’s process are applied, in which the deflection solution of the shell is approximately presented. The effects of thermal load, volume fraction and distribution type of graphene, piezoelectric layer, geometric parameters of the toroidal shell segments, and stiffeners on the torsional buckling load and postbuckling curves are analyzed and investigated in the numerical investigations.

Tailoring of physical properties of glassy selenium (g-Se) by using multi-walled carbon nanotubes (MWCNTs)

The present research reports the studies of the different physical properties of a novel kind of glass nanocomposite sample that belongs to the nano-structuring of glassy selenium (g-Se) by choosing multiwall carbon nanotubes (MWCNTs) as a dopant. The structural analysis of the sample is done by employing different techniques [e.g., Scanning electron microscopy (SEM), X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), and Raman spectroscopy]. The detailed analysis reveals that the MWCNTs are incorporated successfully in the glass matrix of Se. The occurrence of thermally activated glass transition/crystallization in the present glass nanocomposite sample has been investigated by thermal analysis of calorimetric measurements. The thermo-mechanical and electrical properties of this sample have been studied by micro-indentation test, and current–voltage measurements respectively. We have also compared different physical properties of current glass composites with that of g-Se for understanding the consequences of MWCNTs doping in the parent g-Se. The detailed analysis shows that the electrical conductivity, hardness, threshold voltage of resistive switching, and modulus of elasticity of the parent sample (i.e., g-Se) are increased drastically after the doping of MWCNTs, whereas there is a drastic reduction in the thermal stability and volume of the micro-voids.

Development of over 3000 cycles durable macro-encapsulated aluminum with cavity by a sacrificial layer method for high temperature latent heat storage

The high-temperature metallic phase change materials (PCMs) are attracting great attentions as alternatives to sensible heat storage materials in thermal energy storage (TES) systems. However, the high corrosivity, easy leakage and oxidation phenomena of metallic PCMs have limited their applications. This work reports a facile and novel sacrificial layer method with the purpose to create macro-encapsulating aluminum (Al) PCM by alumina (Al2O3) shell characterized by a ‘buffer’ inner cavity. The inner cavity could offer buffer space to accommodate the huge thermal volume expansion of Al core PCM during heating and melting, thereby preventing the breakage of the capsules and ensuring the long-term stability. A series of Al balls with diameters of 4–25 mm were firstly coated with paraffin sacrificial layer then by Al2O3 dough shell, which was finally conducted by the two-step heat treatment, in which a low-temperature stage aimed at removing the paraffin layer while the high-temperature stage aimed at the capsule sintering formation. The final macrocapsules with diameters of 6.5–31.5 mm were obtained, in which the capsules with Al core balls larger than 15 mm showed superior gravimetric and volumetric heat storage density because of their high core–shell ratio. For example, the 25 mm@0.75 mm@2.5 mm macrocapsules could present high heat storage density of 348 kJ/kg and 902 J/cm3 at the temperature range of 600–700 °C. The macrocapsules also showed a long-time thermal cycling stability, since that no damage or leakage was observed over 3000 times of melting and solidification under air atmosphere, indicating that they can be used over 8 years without any degradation of thermophysical properties. This demonstrates the potential application of the Al2O3 encapsulated Al macrocapsules with inner cavity in high-temperature TES systems.

Recycled waste glass usage for construction materials

Recycling glass waste obtained from different industries is an issue in today’s economy. One of the ways of recycling is to produce lightweight ceramic by applying glass waste, clay, and gasifier as raw materials. The present research has been devoted to the evaluation of the influences of different clays extracted from two Latvian quarries (Lielauce un Samini) on the properties of lightweight ceramics. The main criteria of applicated clay as raw materials for producing lightweight ceramic are the following: saturation of SiO2 should be a maximum of 70% and Al2O3 minimum of 12%. The aim of the present research was to elaborate a composition for producing glass ceramic from glass waste with minimum energy consumption with a gasifier. The most important properties of the final product are thermal conductivity, compression strength, volume density, size, granulometry, and pore distribution. Two parameters of them, compression strength and volume density have been tested and analysed in the present research framework. Burning time is one more important additional parameter, which has been considered evaluating the properties of the final product. The obtained volume density is in the range of 226.75 kg/m3 to 475.78 kg/m3 depending on the composition.

Factors contributing to the change in thermoneutral maximal oxygen consumption after iso-intensity heat acclimation programmes

ABSTRACT The factors explaining variance in thermoneutral maximal oxygen uptake (O2max) adaptation to heat acclimation (HA) were evaluated, with consideration of HA programme parameters, biophysical variables and thermo-physiological responses. Seventy-one participants consented to perform iso-intensity training (range: 45%−55% O2max) in the heat (range: 30°C-38°C; 20%−60% relative humidity) on consecutive days (range: 5-days-14-days) for between 50-min and-90 min. The participants were evaluated for their thermoneutral O2max change pre-to-post HA. Participants’ whole-body sweat rate, heart rate, core temperature, perceived exertion and thermal sensation and plasma volume were measured, and changes in these responses across the programme determined. Partial least squares regression was used to explain variance in the change in O2max across the programme using 24 variables. Sixty-three percent of the participants increased O2max more than the test error, with a mean ± SD improvement of 2.6 ± 7.9%. A two-component model minimised the root mean squared error and explained the greatest variance (R2; 65%) in O2max change. Eight variables positively contributed (P < 0.05) to the model: exercise intensity (%O2max), ambient temperature, HA training days, total exposure time, baseline body mass, thermal sensation, whole-body mass losses and the number of days between the final day of HA and the post-testing day. Within the ranges evaluated, iso-intensity HA improved O2max 63% of the time, with intensity – and volume-based parameters, alongside sufficient delays in post-testing being important considerations for O2max maximisation. Monitoring of thermal sensation and body mass losses during the programme offers an accessible way to gauge the degree of potential adaptation.

CO2 Capture Improvement in Polyetherimide Membranes: Effect of Ionic Liquid on the Molecular Mobility

The research described here was aimed at the development of polymeric membranes based on polyetherimide (PEI) containing the ionic liquid (IL) 1-butyl-2,3-dimethylimidazolium hexafluorophosphate ([BMMIM]PF6). The preparation of the PEI-based membranes was carried out via casting of solutions with the incorporation of the IL. The prepared membranes were characterized by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for thermal and free volume properties. CO2 sorption and permeation properties were measured to evaluate the CO2 capture performance of the membranes. The fractional free volume (FFV) of the membranes was around 15%. The incorporation of IL increased the CO2 sorption capacity, promoting an increase of 330% in the solubility coefficient (KD) and resulted in a decrease of 96% in CO2 permeability when compared to the control membrane. The presence of IL in the PEI matrix significantly altered the structural and transport characteristics of the analyzed membranes, being efficient for CO2 capture, as they showed a high CO2 solubility and a decrease in CO2 permeation.

Role of strain rate in phase stability and deformation mechanism of non-equiatomic Fe38-xMn30Co15Cr15Ni2Gdx high-entropy alloy

Excellent combination of strength and ductility makes metastable high entropy alloys (HEAs) stand out from multi-principal elements alloys. In this study, micro-alloying Gd element is effectively solid solutionized in metastable single FCC phase FeMnCoCrNi HEA system, to bring the FCC phase stability decreased that causes a pronounced FCC → HCP phase transformation during compression. In order to decouple the temperature effect from the influence of dynamic strain rate on phase transformation, a wide strain rate range is adopted from 10 −3 –10 −1 s −1 to 1000–5000 s −1 . The results show that the increased strain rate and adiabatic temperature rise both can restrain the phase transformation. Under low strain rates (10 −3 –10 −1 s −1 ), phase transformation is activated in all tested samples and gradually suppressed with the increase of strain rates, because the rate-induced shear bands inhibit the growth of the HCP phase. The reduction of strain hardening during phase transformation is related to the increase of local thermal activation volume due to disentangling of dislocations. Under dynamic strain rates (1000–5000 s −1 ), the phase transformation is completely substituted by deformation twinning due to the significant adiabatic temperature rise. The present work provides insights into the influence of strain rate on phase stability and deformation mechanism in a wide strain rate range. • Solid solution of Gd decreases the FCC phase stability bringing pronounced FCC → HCP phase transformation during quasi-state compression. • Phase transformation related dislocation dissociation enlarges the thermally activated volume causing the decrease in strain hardening rate. • Under low strain rates (10 −3 –10 −1 s −1 ), the increased strain rates activate shear bands earlier that hinder the growth of the HCP phase, it is a rate-related effect on phase transformation. • Under high strain rates (1000–5000 s −1 ), adiabatic temperature rise enhances the phase stability which is a thermo-related effect, co-works with the rate-related effect, making the phase transformation completely suppressed.

Desert cotton and areca nut husk fibre reinforced hybridized bio-benzoxazine/epoxy bio-composites: Thermal, electrical and acoustic insulation applications

Due to increasing environmental concerns, significant attention has been gained for seeking out alternative sources for deforestation and to reduce as much as possible for the utilization of petroleum-based chemicals. In the present work hybrid bio-composites have been developed using epoxy resins (DGEBA-isophoronediamine and DGEBA-phenalkamine) and hybridized blend of bio-based cardanol-diaminodiphenylmethane (C-ddm) benzoxazine and DGEBA-isophoronediamine (bio-benzoxazine: epoxy resin 50:50 wt%)reinforced with desert cotton (DC) and areca nut husk fibres (ANF) separately under appropriate experimental conditions, in order to utilize them for high performance thermal, electrical and acoustic insulation panel applications. Mechanical behaviour, thermal conductivity, thermal resistance, electrical surface resistivity, electrical volume resistivity, sound absorption coefficient and sound transmission loss were studied as per standard methods. Results obtained from different studies infer that hybrid blended cardanol benzoxazine composite panels reinforced with desert cotton sandwich areca nut husk fibre (DC-sw-ANHF) possess appreciable thermal resistivity and electrical volume resistivity and the corresponding values are 0.22141 M2 k/w, and 1.888 × 1010 Ω, respectively. Data obtained from acoustic studies, indicate that all the fibre reinforced composites possess more than 0.7 value of sound absorption coefficient at 6400 Hz. The composite panel specimens developed using both desert cotton, and areca nut husk fibre reinforced with hybridized blend of bio-benzoxazine/epoxy resin can be used as insulation materials in the field of building construction.

A sustainable biochar-based shape stable composite phase change material for thermal management of a lithium-ion battery system and hybrid neural network modeling for heat flow prediction

Electric vehicles are gaining global popularity lately, and along with it, efficient battery thermal management systems (BTMS) are also gaining traction amongst the research community. Phase change material (PCM) based BTMS can be an attractive solution due to its high energy density and isothermal energy exchange. However, pure PCM has some drawbacks like low thermal conductivity, volume expansion, and leakage during phase change. A shape stable composite PCM (SSCPCM) resolves these drawbacks but is an expensive solution due to the high cost of conventional supporting materials. Biochar (BC) based SSCPCM developed in this study can be a cheap and sustainable solution for BTMS. The characterization studies are carried out for combination of pure PCM (Myristyl Alcohol) and biochar at various loadings of 6 %, 12 %, 18 %, and 24 % by weight, using Fourier transform infrared analysis (FT-IR), X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), particle size analysis (PSA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The shape stability studies reveal that the PCM with minimum of 24 % biochar (PCM-BC24) is shape stable. The thermal conductivities and effusivities of pure and shape-stable composite PCMs are also studied. Enhancement in thermal conductivity of PCM-BC24 is studied with the addition of multi-walled carbon nanotubes (MWCNT) in 0.5 % and 1 % concentrations. FT-IR and XRD results reveal that the interaction of biochar and MWCNT with pure PCM is purely physical and chemically stable. The degree of supercooling is reduced by 19.26 %, 23.49 %, and 25.17 % for PCM-BC24 with 1 % MWCNT compared to pure PCM at a heating rate of 5.0, 7.5, and 10 °C/min, respectively. Thermal conductivity and effusivity of PCM-BC24 with 1 % MWCNT are 458.72 % and 146.25 % higher than the pure PCM, respectively. The TGA results reveal that PCMs thermal stability is not adversely affected by the addition of BC & MWCNT. Furthermore, an ANFIS model is developed to predict the heat flow (mW/mg) values of PCM samples and found that the generalized bell-shaped input and linear output membership function is best suitable with a coefficient of determination (R2) of 0.971.

Stress evolution mechanisms under different SSPT-related effects during laser welding

In this study, a thermal-metallurgical-mechanical (TMM) model was developed for finite element (FE) analysis in laser welding of ultra-high-strength steel (UHSS). The solid-state phase transformation (SSPT) model of austenization was improved by introducing a heating rate-dependent coefficient. Seven cases considering different SSPT-related effects (Case 1–5) and different austenization models (Case 5–7) were considered for the simulation of welding stress to study the stress evolution mechanism during welding. The effects include changes in the yield strength, coefficient of thermal expansion, volume strain, and plastic strain, all of which are induced by the SSPT. By comparing the predicted and measured partial austenitized zone (PAZ), it was found the proposed model had good accuracy for the ultra-high heating rates during laser welding. The predicted transverse/longitudinal welding stresses were also in good agreement with the measurements. The results show that each effect can dramatically change the evolution process and the final magnitude and sign of stress. For example, the SSPT-induced plastic strain always results in a plastic strain having the same sign as the stress, and, in return, gives rise to a decrease in the magnitude of stress. In addition, the SSPT-related effects are weakened when the austenization model underestimates the austenite fraction, leading to a larger error in the predicted stress.

Calcium hydroxide and porous silicon-impregnated silicon carbide-based composites for thermochemical energy storage

Thermal energy storage has a prospect for large-scale storage of renewable energy. Thermochemical energy storage using reversible gas–solid reactions can store thermal energy for unlimited periods with high energy density. Calcium hydroxide (Ca(OH)2), which is abundant and environmentally friendly, is one of the most promising materials for thermochemical energy storage systems. However, pure Ca(OH)2 powder has poor power density and bulk stability owing to its low thermal conductivity, volume change, and agglomeration over dehydration–rehydration cycles. Practical composites that can simultaneously overcome these problems have not been reported yet. This study combines Ca(OH)2 with ceramic foam and honeycomb structures of silicon-impregnated silicon carbide (Si–SiC) and demonstrates the improved power density and bulk stability of the resulting composites. The Si–SiC foam composite, loaded in a laboratory-scale fixed-bed reactor, exhibits a thermal discharging power density of 0.71 MW mbed−3, which is 1.6 times that of the pure Ca(OH)2 powder. In addition, the foam composite reduces the volume change by 80% and does not form centimeter-scale agglomerates even after 15 cycles, unlike the pure powder. The results suggest that embedding solid storage materials into thermally conductive open-cell foams can simultaneously enhance power density and bulk stability.

Electric Vehicle Air Conditioning System and Its Optimization for Extended Range—A Review

Environmental protection initiatives are speeding up the replacement of the present IC engine-based transportation system with an electric motor-driven system. In electric vehicles (EV), energy stored in batteries is used for the traction of the vehicle and the operation of the auxiliaries. The range of the electric vehicle was identified to be one of the major challenges faced by the EV segment. The optimization of the consumption of stored energy is the best solution for range improvement in an EV. Auxiliaries in the vehicle include basic accessories such as a lighting system and equipment for improved comfort such as air conditioners. Air conditioning equipment is the major power-consuming auxiliary in an EV apart from the traction motor. This review article discusses the significance and influence of different components of the air conditioning system, and methods followed by researchers to optimize the performance and reduce the energy consumption of the air conditioning system to extend the range of vehicles. The effects of thermal load and volume of space to be conditioned were also considered in this study. This review concludes by stating the different possibilities for the reduction in power consumption and emphasizes zonal air conditioning of occupant space as a solution for reducing energy consumption or increasing the range of EVs. Compared to full-space air conditioning, zonal AC can reduce power consumption by up to 51%.

Simulation of thermal drains using a new constitutive model for thermal volume change of normally consolidated clays

This paper focuses on the thermo-hydro-mechanical behavior of clay surrounding a thermal drain. A new constitutive model for prediction of thermal volume change of clays is presented that incorporates an improvement to existing models by capturing the effect of initial effective stress on the thermal volume change of normally consolidated clay observed in element-scale tests. A numerical framework with the proposed constitutive model was used to simulate the coupled effects of heat transfer, fluid flow and volume change in clay surrounding a thermal drain. The simulated results were validated using experimental data from a large-scale laboratory experiment on a thermal drain under different thermal and surcharge loads. The results indicate that the required surcharge can be reduced when using a thermal drain in lieu of a conventional vertical drain and a significant increase in the rate of consolidation is observed when using a thermal drain. The proposed constitutive model allows better prediction of thermal volume changes of normally consolidated clays as a function of depth which is important to understand the efficient application of in-situ heating for ground improvement.

Optimization and Developmental Validation of 38-plex InDel Panel for Ancestry Inference.

The previously established 38-plex InDel system was optimized and its performance was validated according to the Scientific Working Group on DNA Analysis Method (SWGDAM) application guidelines. The ancestry inference accuracy of individuals from East Asian, European, African and mixed populations was verified. DNA standard sample 9947A was used as the template to establish the optimal amplification conditions by adjusting primer balance, Mg2+ final concentration and optimizing PCR thermal cycle parameters and amplification volume. The allelic dropout, nonspecific amplification and whether the origin of the inferred samples matched the known information were compared to evaluate the performance of this system. The optimal dosage of this system was 0.125-2 ng DNA template. The results of InDel typing were accurate, the amplification equilibrium was good, and the species specificity was good. This system showed certain tolerance to DNA samples including the inhibitor such as hemoglobin (≤80 μmol/L), indigo (≤40 mmol/L), calcium ion (≤1.0 mmol/L), and humic acid (≤90 ng/μL). The system enabled the direct amplification of DNA from saliva and blood on filter paper, and the results of ethnic inference were accurate. The system successfully detected the mixed DNA sample from two individuals. The test results of the system for common biological materials in practical cases were accurate. The results of the 38-plex InDel system are accurate and reliable, and the performance of the system meets the requirement of the SWGDAM guidelines. This system can accurately differentiate the ancestry origins of individuals from African, European, East Asian, and Eurasian populations and can be implemented in forensic practice.

An in silico derived dosage and administration guide for effective thermochemical ablation of biological tissues with simultaneous injection of acid and base

Background and objectives: Thermochemical ablation (TCA) is a thermal ablation technique involving the injection of acid and base, either sequentially or simultaneously, into the target tissue. TCA remains at the conceptual stage with existing studies unable to provide recommendations on the optimum injection rate, and reagent concentration and volume. Limitations in current experimental methodology have prevented proper elucidation of the thermochemical processes inside the tissue during TCA. Nevertheless, the computational TCA framework developed recently by Mak et al. [Mak et al., Computers in Biology and Medicine, 2022, 145:105494] has opened new avenues in the development of TCA. Specifically, a recommended safe dosage is imperative in driving TCA research beyond the conceptual stage.Methods: The aforesaid computational TCA framework for sequential injection was applied and adapted to simulate TCA with simultaneous injection of acid and base at equimolar and equivolume. The developed framework, which describes the flow of acid and base, their neutralisation, the rise in tissue temperature and the formation of thermal damage, was solved numerically using the finite element method. The framework will be used to investigate the effects of injection rate, reagent concentration, volume and type (weak/strong acid-base combination) on temperature rise and thermal coagulation formation.Results: A higher injection rate resulted in higher temperature rise and larger thermal coagulation. Reagent concentration of 7500 mol/m3 was found to be optimum in producing considerable thermal coagulation without the risk of tissue overheating. Thermal coagulation volume was found to be consistently larger than the total volume of acid and base injected into the tissue, which is beneficial as it reduces the risk of chemical burn injury. Three multivariate second-order polynomials that express the targeted coagulation volume as functions of injection rate and reagent volume, for the weak-weak, weak-strong and strong-strong acid-base combinations were also derived based on the simulated data.Conclusions: A guideline for a safe and effective implementation of TCA with simultaneous injection of acid and base was recommended based on the numerical results of the computational model developed. The guideline correlates the coagulation volume with the reagent volume and injection rate, and may be used by clinicians in determining the safe dosage of reagents and optimum injection rate to achieve a desired thermal coagulation volume during TCA.