Simultaneous Application Of Heat Research Articles

Microstructural engineering in lithium garnets by hot isostatic press to cordon lithium dendrite growth and negate interfacial resistance for all solid state battery applications

Hot isostatic press (HIP) post sintering technique was utilized on the garnet structured oxides, prepared by solid state reaction method, to enhance density, Li+ conductivity and barricade lithium dendrite growth. Simultaneous application of heat and isostatic pressure is an effective technique to enhance the grain boundary integrity and minimize the pores, which in turn, increase the relative density of the lithium garnet oxide pellets. The advantage of HIP is well echoed by the enhanced total (grain + grain boundary) Li+ conductivity and transparency of the Li6.16Al0.28Zr2La3O12 (Al-LLZ) pellet. The room temperature (25 °C) total lithium ion conductivity of Al-LLZ and 1 wt% of Li4SiO4 (LSO) added Al-LLZ, were found to be 0.13 mS/cm and 0.3 mS/cm, respectively. This is further enhanced to 0.31 mS/cm and 0.41 mS/cm, respectively, along with improved relative density of around 98% through the HIP treatment. The HIP treated transparent Al-LLZ pellet successfully barricades lithium dendrite growth even at higher current density of 250 μA/cm2 and also reduces the metallic lithium and Al-LLZ interfacial resistance by increasing the lithium wettability.

Microstructural evolution and hardness properties of coir-coconut husk powder reinforced polymer composites subjected to an acidic environment

In this study, coir-coconut husk powder reinforced polymer composite (CCHPRC) prepared by the simultaneous application of heat and pressure, was subjected to an acidic environment and its morphological and hardness properties were investigated. Four test conditions were selected to elucidate the short-term effect of the exposure of the composites to an acidic environment which was achieved by simulating an acidic condition of Sulfuric Acid (H2SO4) solution with a pH of 2.2 at room temperature (27°C). Exposure periods of 3, 6 and 9 days (3PA, 6PA, 9PA) were considered, while samples not exposed to the acid solution were used as control (NP). In order to measure the possible surface degradation and hardness variation of the CCHPRC due to immersion in the acid solution, scanning electron microscopy in addition to energy dispersive spectroscopy (SEM/EDS), and hardness tests were carried out. As a result, the gradual material degradation and poor adhesion between reinforcement and matrix was observed which was confirmed by SEM/EDS analysis. Prolonged acid immersion time seemed to promote an increase in terms of the composites’ hardness. It is possible to conclude that the hardness characteristics of the composite (NP- 12.98 HV; 3PA- 7.27 HV; 6PA- 14.40 HV; 9PA- 19.07 HV) increased after immersion on exposure for 6 and 9 days, in comparison with the control sample.

Individual and combined effects of drought and heat on antioxidant parameters and growth performance in Buffel grass (Cenchrus ciliaris L.) genotypes

Drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. In the last decade, many studies focused on the response of crops to a single stress, nevertheless studying the response of plants to a combination stress may be critical to our understanding of stress tolerance in plants and the development of tolerant genotypes. Buffel grass (Cenchrus ciliaris L.) is a warm-season grass known in arid and semiarid regions for its tolerance to heat and drought stress, productivity, and forage quality. However, in our previous works, several accessions have exhibited different responses to abiotic stresses. Therefore, the objective of this work was to evaluate the effects of combination of drought and heat stresses on biochemical parameters and plant growth and to compare the impacts of the stresses separately and when combined. We found that sensitive genotype exhibited higher lipid peroxidation content, lower total reducing power values and reduced catalase and superoxide dismutase activities than tolerant under drought or heat stress or combination stress. In this study, heat stress had a predominant effect on buffel grass genotypes over drought stress, which explained why simultaneous application of heat and drought revealed similar biochemical and growth responses to the heat stress. Antioxidant metabolism seems to be critical for tolerate abiotic stress. This study may provide useful information to perform a rapid and low-cost characterization in new buffel grass germplasm and to identify genotypes with better growth performance under drought and heat conditions.

Mechanical and in vitro degradation behavior of magnesium-bioactive glass composites prepared by SPS for biomedical applications.

In order to make magnesium (Mg) a successful candidate for fracture fixation devices, it is imperative to control the corrosion rate and enhance its elastic modulus. In the present work, we have prepared bioactive glass (BG) reinforced magnesium composite using spark plasma sintering (SPS). Simultaneous application of heat and pressure during SPS decreased the softening point of BG (600°C), allowing it to coat the Mg particles partially. As a result, BG was found along the Mg particle boundaries, which was confirmed by elemental mapping. Addition of BG improved microhardness and elastic modulus of Mg-BG composites. Corrosion behavior was studied by hydrogen evolution and immersion corrosion in phosphate buffered saline (PBS). After 64 h of immersion, Mg-10 wt % BG composite showed highest corrosion resistance. Quantitative micro-computed tomography (micro-CT) results indicated porosity increase in Mg-BG composites during immersion. The maximum increase in porosity (1.66%) was noticed for pure Mg while the minimum for Mg-10 wt % BG composite. MG63 cell-material interactions, using extract method, showed good cytocompatibility for Mg-10 wt % BG composite. The concentration of Mg ion in cell culture media was measured using atomic absorption spectroscopy after 24 h immersion of Mg/BG composites. The results indicated that using BG as reinforcement and SPS as sintering method; we can prepare corrosion resistant and high modulus Mg-BG composites that can be used for fabricating bone fracture fixation plates. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 352-365, 2019.

Mechanical and dynamic mechanical analysis of jute and human hair‐reinforced polymer composites

Application of light‐weight materials in automotive and structural components such as door panel, Dashboard and internal engine cover play a crucial role in the improvement of vehicle performance. Weight reduction of automotive vehicle components results in less fuel consumption, leading to drastic reduction of CO2 emission. Carbon emission can be minimized through replacement of light‐weight natural fiber reinforced composite‐based components in place of metallic components in the vehicles. Simultaneous application of heat and dynamic loads on polymer composite materials affect crystallinity resulting in the degradation of material properties and its weight. Many researchers have shown interest in the use of bio composites for automotive parts with good mechanical and thermal properties for conventional automotive materials. The present work focuses on the fabrication of jute and human hair‐reinforced epoxy‐based polymer composites with five different fiber compositions. Mechanical properties such as tensile strength and impact energy were analyzed. Storage modulus, loss modulus and damping behavior under different frequencies constituting a function of increasing temperature was observed. The effect of fiber composition and frequency on dynamic behavior of new combination of natural composites was analyzed for determining the viscoelastic behavior of composites. Mechanical properties were found to increase with increase in human hair composition in the composites. The glass transition temperature (Tg) obtained from storage modulus, loss modulus and damping curve exhibits a temperature between 80 and 95°C for all composites. As a consequence, higher fiber content in matrix was observed to allow greater stress transfer at the interface resulting in high dynamic mechanical properties. The experimental results have shown that the natural fiber‐reinforced polymer composite is sustainable in withstanding dynamic loads. POLYM. COMPOS., 40:1132–1141, 2019. © 2018 Society of Plastics Engineers

Drought stress had a predominant effect over heat stress on three tomato cultivars subjected to combined stress

BackgroundAbiotic stresses due to environmental factors could adversely affect the growth and development of crops. Among the abiotic stresses, drought and heat stress are two critical threats to crop growth and sustainable agriculture worldwide. Considering global climate change, incidence of combined drought and heat stress is likely to increase. The aim of this study was to shed light on plant growth performance and leaf physiology of three tomatoes cultivars (‘Arvento’, ‘LA1994’ and ‘LA2093’) under control, drought, heat and combined stress.ResultsShoot fresh and dry weight, leaf area and relative water content of all cultivars significantly decreased under drought and combined stress as compared to control. The net photosynthesis and starch content were significantly lower under drought and combined stress than control in the three cultivars. Stomata and pore length of the three cultivars significantly decreased under drought and combined stress as compared to control. The tomato ‘Arvento’ was more affected by heat stress than ‘LA1994’ and ‘LA2093’ due to significant decreases in shoot dry weight, chlorophyll a and carotenoid content, starch content and NPQ (non-photochemical quenching) only in ‘Arvento’ under heat treatment. By comparison, the two heat-tolerant tomatoes were more affected by drought stress compared to ‘Arvento’ as shown by small stomatal and pore area, decreased sucrose content, ΦPSII (quantum yield of photosystem II), ETR (electron transport rate) and qL (fraction of open PSII centers) in ‘LA1994’ and ‘LA2093’. The three cultivars showed similar response when subjected to the combination of drought and heat stress as shown by most physiological parameters, even though only ‘LA1994’ and ‘LA2093’ showed decreased Fv/Fm (maximum potential quantum efficiency of photosystem II), ΦPSII, ETR and qL under combined stress.ConclusionsThe cultivars differing in heat sensitivity did not show difference in the combined stress sensitivity, indicating that selection for tomatoes with combined stress tolerance might not be correlated with the single stress tolerance. In this study, drought stress had a predominant effect on tomato over heat stress, which explained why simultaneous application of heat and drought revealed similar physiological responses to the drought stress. These results will uncover the difference and linkage between the physiological response of tomatoes to drought, heat and combined stress and be important for the selection and breeding of tolerant tomato cultivars under single and combine stress.

Warm dynamic compaction of Al6061/SiC nanocomposite powders

Powder dynamic compaction is one of the new methods for the production of nanocomposites. In this paper, Al6061/SiCnp nanocomposite is compacted using warm dynamic compaction by simultaneous application of heat and dynamic compressive waves. A comparison between the results of this study and those reported in the literature confirms that the warm dynamic compaction methods are superior to cold dynamic and quasi-static compaction method in densification of nanocomposites especially for high volume fractions of nano particles reinforcement. Mechanical and microstructural characterization of the samples is carried out to investigate the effects of temperature and content level of reinforcement. The results indicate that the increase of nano reinforcement content in warm dynamic compaction leads to reduction of the relative density and increase of hardness and the compressive strength. Moreover, higher compaction temperatures result in enhanced density and lower hardness. It is shown that samples compacted using warm dynamic compaction exhibit lower spring back and ejection force and also the distribution of mechanical properties is significantly more homogeneous. Sensitivity analysis showed that temperature increase has the most effect on homogeneity improvement and reducing dimensional change. Microscopic analyses verified that higher compaction temperature leads to lower porosity and improved metal particle bonding. It seems that agglomeration of nanoparticles and destructive phenomena such as capping and delamination are the main reasons for loss of compressive strength at room temperature. These issues are resolved in warm dynamic compaction by increasing the compaction temperature which leads to better bonding between particles.

Effect of spark plasma sintering pressure on mechanical properties of WC–7.5wt% Nano Co

Abstract In this study, Spark Plasma Sintering (SPS), a relatively fast consolidation method assisted with simultaneous application of heat and pressure, was used to produce bulk carbides from mixed WC–7.5 wt% Nano Co powders. Different pressures ranging from 30 to 80 MPa were applied during sintering to explore its effect on the mechanical properties of resulting carbides. The maximum hardness was found for the samples pressed at 80 MPa, which is ∼1925 HV (18.88 GPa), higher than that of the commercially available cemented carbide tools. The marked changes in porosity, hardness, and crack propagation observed in the samples show that the sintering pressure have considerable impact on the mechanical properties of cemented carbides. In particular, the nature of crack initiation and propagation, which is indicative of the fracture toughness of materials, was studied and clarified.

Simultaneous Application of Heat and Electron Particles to Effectively Reduce the Viscosity of Heavy Deasphalted Petroleum Fluids

Application of ionizing incidents, as an innovative way of combining engineering physics and chemistry to efficiently deliver energy to the electronic structure of the molecules, has introduced great opportunities to the developing oil and gas industry. Although heavy petroleum resources have been considered as a potential alternative to fulfill the growing energy inquiries, the lack of cost-effective technologies for extraction, transportation, or refinery upgrading hinders the development of heavy oil reserves. Nevertheless, electron irradiation technology can economically overcome principal problems of heavy oil processing arising from the heavy oil’s unfavorable physical and chemical properties. This technology promises to increase the yields of valuable and environmentally satisfying products in thermal cracking. Electron particles were observed to reduce the viscosity of heavy deasphalted petroleum fluid and to provide a higher concentration of light hydrocarbons in the final product. This behavior is attributed to the intensified cracking in the presence of ionizing electrons. Molecular distribution of the hydrocarbons in liquid and gas products shows that although simultaneous application of heat and electron particles accelerates the cracking process, the reaction mechanism does not differ from that of thermal cracking. The results also demonstrate the substantial influence of reaction temperature and absorbed dose upon the radiolysis throughput. Moreover, aging analyses of the post-treatment samples proves the time-stable nature of the irradiation products.

Simultaneous application of heat, drought, and virus to Arabidopsis plants reveals significant shifts in signaling networks.

Considering global climate change, the incidence of combined drought and heat stress is likely to increase in the future and will considerably influence plant-pathogen interactions. Until now, little has been known about plants exposed to simultaneously occurring abiotic and biotic stresses. To shed some light on molecular plant responses to multiple stress factors, a versatile multifactorial test system, allowing simultaneous application of heat, drought, and virus stress, was developed in Arabidopsis (Arabidopsis thaliana). Comparative analysis of single, double, and triple stress responses by transcriptome and metabolome analysis revealed that gene expression under multifactorial stress is not predictable from single stress treatments. Hierarchical cluster and principal component analyses identified heat as the major stress factor, clearly separating heat-stressed from non-heat-stressed plants. We identified 11 genes differentially regulated in all stress combinations as well as 23 genes specifically regulated under triple stress. Furthermore, we showed that virus-treated plants displayed enhanced expression of defense genes, which was abolished in plants additionally subjected to heat and drought stress. Triple stress also reduced the expression of genes involved in the R-mediated disease response and increased the cytoplasmic protein response, which was not seen under single stress conditions. These observations suggested that abiotic stress factors significantly altered turnip mosaic virus-specific signaling networks, which led to a deactivation of defense responses and a higher susceptibility of plants. Collectively, our transcriptome and metabolome data provide a powerful resource to study plant responses during multifactorial stress and allow identifying metabolic processes and functional networks involved in tripartite interactions of plants with their environment.

Material Flow Analysis: An Effectiveness Assessment Tool for In Situ Thermal Remediation

In situ thermal desorption (ISTD) is a remediation technique that increases the effectiveness of soil vapor extraction through the simultaneous application of heat and vacuum. In this study, ISTD was applied to remove a chlorinated solvent source from unsaturated soil beneath an existing aboveground infrastructure. A material flow analysis (MFA) was applied for the first time to assess the effectiveness of ISTD in the vadose zone and to reveal the total emission of chlorinated solvents into the environment before and during remediation. The principle of matter conservation used in MFA enabled the quantification of chlorinated solvent flows in all matrices affected: soil, groundwater, and soil vapor. The MFA results revealed that the mass removed by ISTD was similar to the mean chlorinated solvent mass estimated to have been present in the soil before remediation, indicating high effectiveness in contaminant removal. The remediation target value in soil vapor was achieved after 9 mo of remediation, demonstrating the time efficiency of ISTD for this particular site. The MFA additionally provided an overview of the processes and contaminant transformations occurring in the soil, water, and air compartments during the course of remediation.

Modelización de la inactivación termosónica de Staphylococcus aureus, un enfoque multifactorialModeling Staphylococcus aureus thermosonic inactivaction, a multi-target approach

In recent years different emerging technologies have been evaluated such as ultrasound, which is usually combined with other preservation factors in order to increase microbial inactivation. Staphylococcus aureus inactivation was performed by simultaneous application of heat (40, 50, or 60 °C) and low frequency ultrasound (20 kHz) at selected wave amplitudes (60, 75, or 90 µm) in culture broth (a w 0.96, and pH 3.5) with different concentrations of vanillin (200, 350, or 500 mg/kg). Death curves were fitted with the Fermi model. A synergic effect was observed when temperature is near to 40 °C at different ultrasonic amplitude waves and vanillin concentrations. Several studied combinations of ultrasound, temperature, and vanillin concentration could be applied in the food industry. En los últimos años se han evaluado diversas tecnologías emergentes como el ultrasonido, el cual es combinado con otros factores de conservación para aumentar su eficacia para la inactivación microbiana. La inactivación de Staphylococcus aureus, se llevó a cabo aplicando simultáneamente temperatura (40, 50 o 60 °C), ultrasonido de baja frecuencia (20 kHz) con diferentes amplitudes de onda (60, 75 o 90 µm), y diferentes concentraciones de vainillina (200, 350 o 500 mg/kg) como antimicrobiano, en medios de cultivo con a w 0,96 y pH 3,5. Se modelaron las curvas de muerte con el modelo de Fermi. Se encontró un efecto sinérgico de los factores estudiados, especialmente a temperaturas cercanas a 40 °C con diferentes amplitudes de onda ultrasónicas y concentraciones de vainillina. Los resultados obtenidos demuestran que varias de las combinaciones estudiadas podrían tener aplicación en la industria de alimentos.

Using Thermomechanical Conditioning Cycles to Improve Fracture Toughness of Low Carbon Steel

The improvement of material toughness has significant industrial applications. In this article, the thermomechanical conditioning (TMC) cycle (which involves simultaneous application of heat to a moderate temperature combined with a tensile load, followed by unloading and cooling to room temperature) was used to improve the fracture toughness of the material. Apparent fracture toughness (Ka) is denoted to represent the fracture toughness of cracked components after the application of TMC cycles. The TMC cycles result in a significant increase in the apparent fracture toughness (Ka) of AS 1548 grade 7-460R steel as compared to the fracture toughness (KIC) of the original material. It is found that the improvement in the apparent fracture toughness of the material was due to the increase in plastic strain and the plastic zone size ahead of the crack tip that occurred after applying TMC. In this study, both the apparent and original fracture toughness (Ka and KIC) are evaluated using the cylindrical notched tensile (CNT) technique, which is considerably cost effective over the standard compact tension specimens (ASTM E399).

Thermoultrasonication Eliminates Salmonellae from Intact Eggshells without Changing the Functional Properties of their Components

ABSTRACTWe have previously reported that the simultaneous application of heat and ultrasound (thermoultrasonication) to intact eggs allows a reduction in the number of Salmonella enterica serovar Enteritidis present on the shell to a safe hygienic level in less severe conditions (temperature and time) than those usually recommended for common pasteurization. In the present work, the effect of thermoultrasonication on selected functional properties of egg compounds (shelf‐life, emulsifying and foaming capacities, emulsion and foam stabilities, texture properties of egg white gel, breakage resistance of shell, and sensory properties of cooked egg) has been studied under the conditions previously defined (54 °C for 5 min) for the developed treatment. No significant differences were obtained in any of properties assayed between thermoultrasonicated and untreated (fresh) eggs. We concluded that it is possible to pasteurize the surface of intact eggs by applying a thermoultrasonic treatment yielding a product with a safe level of S. Enteritidis and cause negligible damage to the thermolabile egg components.

Role of heat treatment in childhood cancers: Distinct resistance profiles of solid tumor cell lines towards combined thermochemotherapy

Since information on the efficacy of hyperthermia in combination with chemotherapy on pediatric tumors is limited, we performed a systematic analysis on the synergistic effects of a combined application of heat and chemotherapy on 20 tumor cell lines derived from patients with neuroblastomas, Ewing tumors, germ cell tumors (GCT), and osteosarcomas. Cisplatin (cDDP), a cross-linking agent, and etoposide (VP-16), a topoisomerase II inhibitor, were examined either alone or in combination with heat (42 degrees C, 43 degrees C) by using the XTT-assay 1. Our data demonstrate that heat stress at 43 degrees C for 1 hr, but not at 42 degrees C, leads to a notable cytotoxic effect on the different tumor cells. The comparison of mean survival fractions reveals values between 62% for neuroblastoma cells and 76% for Ewing tumor cells. Analyzing the sensitivity to chemotherapy alone, our results show that cDDP (5 microg/ml) reduces cell growth to 47% in Ewing tumor cells, to 61% in neuroblastoma cells, to 75% in GCT cells, and to 76% in osteosarcoma cells. Treatment with VP-16 (10 microg/ml) decreases cell survival to mean values between 58% (neuroblastomas) and 77% (osteosarcomas). Simultaneous application of heat and chemotherapy enhances synergistically cDDP cytotoxicity in all tumor types tested, whereas the efficacy of VP-16 is only slightly influenced by additional application of hyperthermia. The cytotoxicity of cDDP (5 microg/ml) can be increased by a factor of between 1.5 and 2.5 at 42 degrees C and from 2.6 to 14.0 at 43 degrees C. Furthermore, the results show that the sensitivity to heat (43 degrees C) as well as the sensitivity to chemotherapy and combined thermochemotherapy varies considerably between cell lines of the same tumor group. Simultaneous application of hyperthermia synergistically enhances the cytotoxicity of the alkylating agent cDDP, but not of the topoisomerase II inhibitor VP-16, in a defined spectrum of cell lines from different pediatric tumor entities.

Detwinning YBa2Cu3O7−δ thin films

Single crystals of YBa2Cu3O7-δ (YBCO) have been detwinned under the simultaneous application of heat and uniaxial stress. This approach, however, has proved futile in thin films as they become heavily twinned due to strain from the underlying substrate as well as the orthorhombic unit cell. This lack of control over twinning has made it difficult to determine the role that twins play in determining the transport properties of films. Here, we present a technique for detwinning YBCO thin films. The detwinning in YBCO thin film is achieved by suspending a portion of the YBCO film above the underlying substrate. The suspended material is no longer influenced by the confining effects of the substrate and this allows it to detwin under the application of a uniaxial stress brought about by an anneal. With this technique, we are able to produce high-quality detwinned regions that will help aid the understanding of transport mechanisms in YBCO.

Rheological properties of yoghurt made with milk submitted to manothermosonication.

Manothermosonication (MTS) treatments, the simultaneous application of heat and ultrasound under moderate pressure, of milk during 12 s at 20 kHz ultrasound amplitude, 2 kg pressure, and 40 degrees C allowed elaboration of yoghurts with rheological properties superior to those of control yoghurts elaborated with untreated milk. Measurements performed on intact samples (compression tests, relaxation tests, and texture profile analysis) and on slowly stirred samples (flow curves, apparent viscosity, yield stress, and viscoelastic properties) showed that MTS yoghurts had stronger structures, which resulted in higher values of almost all of the many relevant rheological parameters. Homogenization of fat globules brought about by MTS treatments is not responsible for the superior properties of MTS yoghurts, because the control yoghurt was also elaborated with homogenized milk. These results show that MTS could be a useful tool to improve the texture of yoghurts.

The effects of manothermosonication on tomato pectic enzymes and tomato paste rheological properties

The effect of manothermosonication (MTS), the simultaneous application of heat and high energy ultrasound waves under moderate pressure, on tomato juice rheology and on tomato pectinmethylesterase (PME) and polygalacturonase (PG) activity in tomato juice was examined. Tomato juice was subjected to MTS treatments (20 kHz, 2 kg pressure, 117 μm amplitude and 70 °C), or to control thermal treatments (TT), for 1 min. Flow curves, yield stress and apparent viscosity were measured on both kind of samples. Apparent viscosity of MTS samples were 1.6-fold higher than that of TT samples. Yield stress values were also 2.2-fold higher in MTS than in TT samples. Flow curve values were fitted to the power law equation; MTS samples showed about 1.9-fold higher consistency values and lower flow indexes, n=0.190 vs. n=0.126, than TT samples. MTS samples retained about 20% more serum than TT samples after centrifugation. TT inactivated about 38% of the initial PME activity whereas PME activity was undetectable in MTS-treated tomato juice. TT left PG unaffected whereas MTS treatments inactivated 62% of total PG activity. These results suggest, that MTS could be an useful technology to obtain high viscosity and consistency tomato juice.

Inactivation of proteases and lipases by ultrasound

The inactivation of phospholipase A 2, α-chymotrypsin, trypsin and porcine pancreatic lipase by heat and manothermosonication (MTS), and the simultaneous application of heat and ultrasound under moderate pressure, has been studied in different treatment media. MTS sensitivity varied strongly for the different enzymes. Whereas phospholipase A 2 was almost insensitive to MTS treatments, α-chymotrypsin and porcine lipase MTS inactivation was much faster than heat inactivation. Trypsin heat inactivation was very different at low than at high temperatures. At low temperatures, it did not follow first order kinetics, contrary to what happened at high temperatures. MTS accelerated trypsin inactivation only at low temperatures. MTS changed also the inactivation order of trypsin (at low temperatures), α-chymotrypsin and porcine lipase; whereas heat inactivation of these enzymes did not follow first order kinetics, MTS inactivation fitted this well.

Influence of Irradiation on the Risk of Transmission of HIV in Bone Grafts Obtained from Appropriately Screened Donors and Followed by Radiation Sterilization.

We studied the effects of radiation (electrons of 6.2 MeV) at different temperatures with respect to the inactivation of the human immunodeficiency virus to determine the radiosensitivity of the virus. Using a mathematical model describing the dependence on radiation dose of the proportion of sterile items in a population of bone allografts contaminated by HIV, and subjected to irradiation, we have commented on and explained the calculation of the sterility assurance level in bone transplantation according to different doses of irradiation at different temperatures. Simultaneous application of heat and radiation increases inactivation of HIV. Given the relative imprecision of viral sensitivity curves and the impossibility of knowing the number of viral particles in a patient at a given moment of the disease, irradiation does not authorize bone transplantation without screening. However, irradiation can be considered as a serious adjuvent to decrease the risk of contamination after screening.