Search

Spray drying is an important industrial method for the preparation of B. thuringiensis powder from fermentation liquor. The effect of spray drying on the crystal proteins, however, has not been reported in the literature so far. The present study systematically investigated the effect of inlet air temperature, outlet air temperature, atomizing air pressure and additives (including organic and inorganic auxiliaries) on the thermal destruction of crystal proteins of B. thuringiensis. The results indicated that the content of crystal proteins of B. thuringiensis powder decreased with increased inlet air temperature, outlet air temperature and atomising air pressure. The pseudo-z values for inlet air temperature, outlet air temperature and atomizing air pressure were 826.4 ℃, 204.0 ℃ and 4.74 MPa, respectively. Among them, the outlet air temperature was a major parameter influencing the thermal destruction of crystal proteins, therefore, the decrease of the outlet air temperature was beneficial to increase the protein content in powder. Although the spray drying had an adverse effect on crystal proteins, the crystal protein content in spray-dried powder approached that in freeze-dried powder when the inlet air temperature of 165 ℃, outlet air temperature of 70 ℃ and atomizing air pressure of 0.15 MPa were employed. The addition of some organic and inorganic auxiliaries to fermentation liquor can protect the crystal proteins from heat damage. [ABSTRACT FROM AUTHOR]

Objective: The use of energy during minimally invasive surgery is associated with thermal damage that can affect the process of wound healing. Methods: This was a randomized clinical trial including 78 women who underwent total laparoscopic hysterectomy. Patients were randomized based on the device used for colpotomy, monopolar hook versus harmonic scalpel. The thickness of the cauterized margins in the cervicovaginal tissues of the hysterectomy specimens was measured by the pathologist. Results: The primary outcome was the amount of lateral thermal damage based on histologic assessment. Secondary endpoints included postoperative pain scores and postoperative complications. Baseline characteristics were comparable between the two groups. The amount of thermal injury in the monopolar group was significantly greater in only one region, the right lateral order of the cuff (3.85 ± 1.01 mm vs. 3.08 ± 0.95 mm (p = 0.001)). With regard to secondary outcome measures, there was no significant difference between the two groups. Conclusion: The use of the harmonic device was associated with significantly less tissue damage during colpotomy in the right lateral cuff region. This is especially important in overweight and obese women in whom the distance between the cervix and the ureter is shorter. Trial Registration https://en.irct.ir/trial/33902?revision=61236. IRCT20180130038567N2. [ABSTRACT FROM AUTHOR]

The modification of polydimethylphenylsilazane with an epoxy oligomer for use as a binder in the technology of producing ceramic matrix composites (CMCs) is considered. As a result of the modification, the yield of pyrolysis residue increased from 21 to 60 wt %. [ABSTRACT FROM AUTHOR]

A mathematical model of the process of thermal destruction of polymer binders is developed, taking into account the experimentally established dependencies of the decomposition depth on temperature and the amount of coke residue on the heating rate. A method for determining the kinetic parameters of the process by the method of inverse problems is developed. The kinetic parameters of the model for six binders are determined. [ABSTRACT FROM AUTHOR]

The influence of the oxygen content in the gas phase on the thermal destruction and combustion of peat and coals with various degrees of metamorphism were studied using a device for synchronous thermal analysis to optimize the conditions for obtaining pulverized coal fuel. It was found that the thermal destruction rate decreases at higher degrees of metamorphism (e.g., 2.69%/min for peat; 1.48%/min for brown coal; 0.55%/min for lean coal, and 0.30%/min for anthracite). The volatile component release temperature decreases (from 420°C for lean coal to 220°C for peat) and remains approximately the same in the presence of oxygen up to the composition of synthetic air. The structure of peat particles was studied on a scanning electron microscope. They have an elongated shape measuring from 50 to 400 μm in size. The predominant grain structure is cellular, or less often – fibrous and layered. The onset combustion temperature of peat-contained carbon is about 340°C. The processes are accompanied by the release of a significant amount of gases, such as CO2, H2O, H2, SO2, NO, and NO2. [ABSTRACT FROM AUTHOR]

Thermal stability of macrocyclic complexes with alkaline earth metal salts is of crucial importance for their applicability as the components of new electrolytes, ionic liquids and precursors in chemical vapor deposition processes. The complexes of 18-crown-6 and stereoisomeric dicyclohexano-18-crown-6 with alkaline earth metal halides were synthesized and studied by the combination of simultaneous DSC/TGA and FTIR-spectroscopy. The stability of these compounds depended on the size of the cation and anion as follows: Ba2+ < Sr2+ < Ca2+ and Cl− < Br− ≈ I−. The two-stage mechanism of destruction was found for the complexes with CaCl2, SrBr2, SrI2. This implies, most probably, the coexistence of two conformationally nonequivalent forms of the macrocycles with different thermal stability rather than the destruction of the macrocycle at high temperatures. The revealed trends, in our opinion, were caused by changes in the interaction energy between macrocycle and metal cation. [ABSTRACT FROM AUTHOR]

The editorial in "Frontiers in Thermal Engineering" discusses the challenges faced by researchers in studying heat transfer mechanisms, particularly in relation to computational modeling and thermal radiation. The text highlights the complexities of radiative transfer calculations in absorbing and scattering media, such as gases, liquids, and solids with microcracks or bubbles. It also addresses the importance of using accurate models for radiative transfer in solving heat transfer problems. The editorial emphasizes the need for simplified mathematical models, like the transport approximation or P1 approximation, in addressing various heat transfer issues, including those involving phase changes and thermal destruction in materials. [Extracted from the article]

The ratio of monomeric units is one of the main characteristics of lignin, which affects the possibilities and strategies for further processing. Pyrolytic and thermal desorption decomposition of lignins followed by mass detection of macromolecule fragments are the most common methods for determining the amount of lignin structural units. Two methods of thermal decomposition of lignin were studied: thermal desorption–GC/MS (TD–GC/MS) and pyrolysis–GC/MS (Py–GC/MS). It was noted that, when using different thermal decomposition modes, the composition of the products changes, which affects the accuracy of determining the amount of lignin structural fragments. This article investigated the influence of the sample weight, the thermal decomposition temperature, and the duration of the process in various modes on the quantitation of the lignin structural units. The optimal process conditions were established. It was shown that the DS–Py–GC/MS with cryofocusing, a sample weight of 0.2–0.4 mg, and heating from 50 to 400 °C at a rate of 120 °C/min are preferable. The HSQC NMR was used as a comparison method to obtain the content of the S/G/H units. The results showed the applicability of the proposed approaches to hardwood lignins close to native. [ABSTRACT FROM AUTHOR]

Pyrolytic gas chromatography and X-ray photoelectron spectroscopy were used to analyze the stability of bridging groups in polyether ether ketone (PEEK) at temperatures of 400–650 °C and bombardment with argon ions of various energies and intensities. Both thermal and ionic exposures lead to the destruction of bridging C=O groups and ether C—O—C bond between the aromatic rings of PEEK. [ABSTRACT FROM AUTHOR]

Novel nanomaterials were synthesized by thermal structuring of new soluble ferrocene-containing polychalcones. The products were studied by gel permeation chromatography, IR spectroscopy, transmission electron microscopy, scanning electron microscopy, and TGA. According to transmission electron microscopy data, the statistical average sizes of magnetic nanoparticles ranged from 4 to 45 nm. X-ray diffraction studies of the samples showed the overwhelming predominance of iron in the zero-valent state (Fe0) in the iron-containing nanoparticles. [ABSTRACT FROM AUTHOR]

Milled peat must be dried for the production of peat fuel briquettes. The current trend in the creation of drying technologies is the intensification of the dehydration process while obtaining a high-quality final product. An increase in the temperature of the drying agent, above 300 °C, significantly accelerates the reaching of the final moisture content of the peat. In the final stage, it is also accompanied by partial thermal decomposition of the solid phase. Its first stage, which is the decomposition of hemicellulose, contributes to a decrease in weight and an increase in the caloric content of the dry residue. The development of high-temperature drying modes consists of determining the temperature and velocity of the drying agent, wherein the duration of the material reaching the equilibrium moisture content will be minimal and the temperature of the material will not rise above the second-stage decomposition temperature of cellulose. This problem can be solved by the mathematical modeling of the dynamics of peat particles drying in the flow. The article presents a mathematical model of heat and mass transfer, phase transitions, and shrinkage during the dehydration of milled peat particles. The equations of the mathematical model were built based on the differential equation of mass transfer in open deformable systems, which, in the absence of deformations, turns into the known equation of state. A numerical method for implementing a mathematical model has been developed. The adequacy of the mathematical model is confirmed by comparing the results of numerical modeling with known experimental data. [ABSTRACT FROM AUTHOR]

A technological unit is described that allows the recovery of waste from small-scale wholesale industries that produce noise-absorbing materials. The unit, with a capacity of 50 kg/h for raw material, makes it possible to process incoming waste during oxidative pyrolysis process both in the liquid and solid states. It is shown that the unit provides conversion of gaseous products of the first processing stage into simple low-danger compounds at the final stage. [ABSTRACT FROM AUTHOR]

Using a variety of physicochemical characterization techniques, we have determined the composition and chemical formula of lanthanum and neodymium compounds with phthalic acid, synthesized for the first time. The compounds have been shown to have similar chemical formulas: La2(L)3·7H2O and Nd2(L)3·6H2O. We have examined the thermal destruction of the synthesized compounds. The proposed schematic structure of the La complex consists of zigzag 2D polymer layers, which are cross-linked by water molecules to form a 3D structure—a supramolecule. [ABSTRACT FROM AUTHOR]

The process of inorganic and organic components temperature transformation of metal waste into solid and gaseous products in a continuous hot briquetting muffle furnace has been studied. The composition of the hydrocarbon atmosphere formed in the muffle under conditions of limited access to the oxidizer has been determined. It is shown that the thermal destruction of the coolant oil phase proceeds according to a complex mechanism of consecutive reactions, including polycondensation, polymerization, and deep compaction with a constant decrease in the hydrogen content and ends with the formation of a coke‑like carbon residue on the surface of metal particles and an air suspension of finely dispersed carbon particles (smoke). When it is heated to hot briquetting temperatures of 750–850 °C, chemically active dispersions of ferrous metals are protected from oxidation first by a hydrocarbon gas with a density of 9.0–13.5 kg/m3, then by a pyrocarbon coating with a thickness of 0.1–0.3 mm up to the completion of the processes of pressing and cooling the briquette.

The pathologies of parathyroid glands are widespread among endocrine system diseases, excluding diabetes and thyroid pathology. There are only two methods that are used to treat hyperparathyroidisms, such as surgery and conservative therapy. However, transracial thermal destruction methods (ablation) have recently appeared in clinical practice. The methods have good precision and connect with physical phenomena, such as interaction laser, radiofrequency, microwave, and HIFU irradiation with bio substance. The review is dedicated to critically analyze the modern methods for local thermal destruction of the hyper-functioning parathyroid glands. The review includes data from randomized clinical trials from 2012 to 2021. The studies were from Google Scholar and Pubmed with a total number of 1,938 patients (laser ablation ― 216 patients, radiofrequency ablation ― 225, microwave ablation ― 1467, high-density ultrasound ablation ― 30 patients). Recommendations methods of thermal destruction application were obtained during the review. Furthermore, we have designed some algorithms for hyperparathyroidism treatment. Moreover, thermal destruction methods were observed. There are four modern methods of thermal destruction which have been analyzed like alternatives to surgery. Each of them has advantages and disadvantages, its profile of safety and effectiveness. After processing information from a proven database, the most popular among specialists is methods of microwave ablation. However, laser ablation is more effective than other ways.

The thermodestructive distillation of vacuum gasoil with the production of an ultradispersed catalytic system containing nickel was investigated. The results from the treatment of fuel oil with this catalytic system at a pilot plant are presented. It was established that in the presence of nickel 2-ethylhexanoate it is possible by thermodestructive distillation of vacuum gasoil up to 405°С to isolate 61.2 wt.% of distillate fractions. When 10 wt.% of the distillation residue formed during the distillation of vacuum gasoil was used in the treatment of fuel oil by thermal action 64.6 wt.% of distillate was obtained. [ABSTRACT FROM AUTHOR]

A technology for the production of greases from polymeric household waste has been proposed, including the stage of boiling the polymer in a solvent, which is used as a used motor oil SAE10W-40. In the production of greases using this technology, a significant amount of used polymer products is utilized, while the share of waste from low-pressure polyethylene and polypropylene (PP) is, respectively, 20-50% of the mass and 50-75% of the mass. This approach makes it possible to significantly expand the raw material base of the specified technological process and, due to the involvement of relatively cheap raw materials, significantly reduce the cost of finished products. The results of the study of the adhesive properties of the obtained lubricants allow us to give the following recommendations: for lubricants based on low-pressure polyethylene with a polymer: oil ratio of 1: 1, the rational rotation speed was no more than 2850 rpm, with a ratio of 1: 3 - about 3950 rpm and with a ratio of 1: 5 - up to 5300 rpm; rational rotation speed for lubricants based on PP at a polymer: oil ratio of 1: 1 does not exceed 3600 rpm, at a ratio of 2: 1-4900 rpm and at a ratio of 3: 1 - 6000 rpm. [ABSTRACT FROM AUTHOR]

Utilization of persistent organic pollutants (POP) is an urgent problem all over the world. POP cause great harm to human health and the environment. For more than 20 years, scientists offer different methods and approaches to dispose of POP, but still there is no safe and economically advantageous method of utilization these pollutants. This paper proposes an environmentally friendly two-step approach (chemical functionalization and thermal destruction) to disposal of POP. We have selected the commercial mixtures of polychlorinated biphenyls "Sovol," "Trichlorbiphenyl" and individual trichlorobiphenyl congeners (PCB 29), pentachlorobiphenyl (PCB 101) as the objects of our study. From these initial components, we synthesized mixtures of hydroxy derivative polychlorinated biphenyls. It has been established for the first time that the best pre-prepared mixtures for burning are hydroxy derivatives. We have found that the thermal destruction of all hydroxy derivatives to the simplest volatile substances (CO2, H2O, HCl, etc.) takes place without the evaporation process. In our studies, we analyzed the thermal destruction of the initial mixtures "Sovol," "Trichlorbiphenyl" and their respective hydroxy and methoxy (hydroxy) derivatives. We have shown that the thermal destruction of hydroxy derivatives of PCB is a more environmentally friendly process in comparison with the thermolysis of unsubstituted commercial mixtures and methoxy (hydroxy) derivatives. The obtained results might be useful for the development of an integrated approach of PCB destruction through two stages: The first is the chemical, and the second is the thermal. [ABSTRACT FROM AUTHOR]

Copyright of Eastern-European Journal of Enterprise Technologies is the property of PC TECHNOLOGY CENTER and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This work is the first attempt to study the physicochemical properties of ionogels - quasi-solid hybrid materials formed by ionic liquids (ILs) − 1-butyl-3-methylimidazolium (BMIm+) salts with dicyanamide- (DCA−), bis(trifluoromethylsulfonyl)imide- (TFSI−), and trifluoromethanesulfonate- (Otf−) anions - and halloysite, a powdered clay filler with nanotube particles (at the IL:Hal molar ratio of 2:1) in order to find possible new applications of ionic liquids and industrial minerals. The electron microscopy, TG, and DSC analysis, FTIR spectroscopy, X-ray diffraction analysis, conductometry and cyclic voltammetry methods are used to investigate the anion effect on the IL interaction with halloysite. It has, for the first time, been found that the distinguishing feature of halloysite interaction with an IL determining the structural changes in the clay mineral and electrochemical characteristics of the ionogels is partial dehydration of the clay and absorption of the released water by the ionic liquid. It is shown that the halloysite dehydration effect depends on the IL hydrophilicity determined by the anion type, corresponds to the series: BMImDCA > BMImOtf > BMImTFSI. The electrochemical and thermal behaviour of ILs confined within a halloysite matrix differs from that of bulk ILs and is controlled by the anion type. Temperature dependences of the structural resistance of the halloysite filler are radically different for the ILs with high and low hydrophilicity. The effects resulting from the formation of halloysite-based ionogels can be of interest to those who develop quasi-solid ionic conductors that can work within a wide temperature range.

Milled peat must be dried for the production of peat fuel briquettes. The current trend in the creation of drying technologies is the intensification of the dehydration process while obtaining a high-quality final product. An increase in the temperature of the drying agent, above 300 °C, significantly accelerates the reaching of the final moisture content of the peat. In the final stage, it is also accompanied by partial thermal decomposition of the solid phase. Its first stage, which is the decomposition of hemicellulose, contributes to a decrease in weight and an increase in the caloric content of the dry residue. The development of high-temperature drying modes consists of determining the temperature and velocity of the drying agent, wherein the duration of the material reaching the equilibrium moisture content will be minimal and the temperature of the material will not rise above the second-stage decomposition temperature of cellulose. This problem can be solved by the mathematical modeling of the dynamics of peat particles drying in the flow. The article presents a mathematical model of heat and mass transfer, phase transitions, and shrinkage during the dehydration of milled peat particles. The equations of the mathematical model were built based on the differential equation of mass transfer in open deformable systems, which, in the absence of deformations, turns into the known equation of state. A numerical method for implementing a mathematical model has been developed. The adequacy of the mathematical model is confirmed by comparing the results of numerical modeling with known experimental data.

In the canning industry, thermal preservation processes typically are designed based on Clostridium botulinum thermal destruction kinetics. However, some bacteria can still survive, necessitating implementation of stricter time-temperature regimen for sterilization process. The aim of this study was to compare processing effectiveness at F0 (sterilization value) 8 ±1 min from the perspective of the vegetable-based product canning facility, while analyzing the inactivation, viability, and recovery of thermophilic bacteria. Four commercial products [tomato soup and rassolnik soup - acidified food (AF), and mushroom soup and pea porridge - low-acid food (LACF)] with different heat transfer characteristics (convection and conduction) were inoculated with 6.6 log spores/ml Geobacillus stearothermophilus LMKK 244 (reported as DSM 6790 10 and ATCC 10149 in other collections) and 4.8 log spores/ml Thermoanaerobacterium thermosaccharolyticum DSM 571 10 spore suspensions. Food samples contaminated with bacterial spores were processed in a steam-air retort at 118 °C for 75 min. G. stearothermophilus and T. thermosaccharolyticum growth was not detected in AF samples (pH = 4.4 and 4.5), but was observed in LACF samples (pH = 5.1 and 5.8). Practical evaluation showed that T. thermosaccharolyticum did not survive o thermal processing, which was verified using a presence/absence test after incubation at 55 C. G. stearothermophilus did not survive thermal processing, but recovered in pea porridge (pH = 5.8) during incubation. Our observations showed that food pH is a crucial factor determining microorganism survival during heat treatment and may be used by the vegetable-based product canning facilities to improve the food sterilization conditions. [ABSTRACT FROM AUTHOR]

The possibility of using heating of body tissue upon excitation of surface plasmons in two-layer spherical metal-graphene nanoparticles for thermal destruction of malignant neoplasms has been analyzed. Drude and Kubo models have been used to determine the frequency dependences of the dielectric function of the metal core and the conductivity of the graphene shell, respectively, and the distributions of temperatures in tumor tissue and surrounding healthy tissue have been determined by solutions of nonhomogeneous thermal conductivity equations. Values of thermophysical parameters of tumor tissue and healthy human tissue known from the literature have been used for numerical estimates and calculations. The evolution of the frequency dependences of the polarizability and absorption cross-sections of the indicated nanoparticles with the variation of the radius and material of the metal core and the thickness of the graphene shell has been studied. It has been shown that an increase in the radius of the metal core or thickness of the graphene shell results in an increase in the maximum values of the imaginary part of the polarizability and absorption cross-section, which is associated with increased interaction with the electromagnetic wave with increasing bulk metal content in the composite nanoparticle and with high concentration of free electrons in graphene layers. The possibility of spectral shifts of the polarizability maxima and the absorption cross-section with the variation of the core material of a two-layer nanoparticle, due to the essential difference in the values of the frequencies of bulk plasmons and the contribution of the ion core to the dielectric function, has been demonstrated. It has been established that the thermal conductivity is quasi-steady in the problem of heating of body tissue upon excitation of surface plasmon resonance in a composite nanoparticle. It has been proved that this method of cancer therapy is harmless to healthy tissue surrounding the tumor due to their extremely low heat. The results of numerical modeling demonstrate the need to use a conglomerate of metal-graphene nanoparticles in order to increase the effectiveness of therapy. [ABSTRACT FROM AUTHOR]

Copyright of News of Kazakhstan Science / Novosti nauki Kazahstana is the property of NCSTE (JSC National Center for State Scientific and Technical Evaluations) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The thermal and physico-mechanical properties of polyethylene composites with additives of microcrystalline and nanofibrillar cellulose (MCC and NFC) are investigated. Based on the results of the performed thermogravimetric analysis, the main temperature characteristics of the thermal and thermooxidative destruction of the obtained compositions are determined. The composition of the pyrolysis products of composite materials is analyzed using the method of pyrolytic chromatography–mass spectrometry. The effect of MCC and NFC additives on the nature of the mass distribution of hydrocarbon pyrolysis products of composite materials is established. This study also carries out a comparative assessment of the effect of MCC and NFC as fillers on the deformation and strength characteristics of polyethylene composites. [ABSTRACT FROM AUTHOR]

The effect of paper thermal destruction on its luminescence spectra and luminescence excitation spectra in the spectral ranges of 400-550 nm and 250-450 nm, respectively, was studied. It is proposed to use the characteristic changes in the intensity and shape of the luminescence spectra as a criterion for the state of paper insulation of power transformers. On the basis of the analysis performed, it was concluded that when luminescence is excited at a wavelength of 360 nm, none of the main components of the paper can contribute to the recorded luminescence spectra. It is assumed that the resulting luminescence spectra are due to the emission of various impurities that enter the paper during its production.

The article presents a schematic diagram of obtaining the components of technological and boiler fuels from polymer raw materials represented by materials from low and high pressure polyethylene, polypropylene and polystyrene. This scheme is based on the process of non-catalytic thermal destruction of raw materials in a batch reactor and consists of a section for preparation of raw materials, a section for thermal destruction as well as the fractionation of the resulting products. The given scheme on an industrial scale, depending on the properties of the raw material, makes it possible to obtain 10-20% (mass) of the fraction - 200°C, 30-50% (mass) of the 200-360°C fraction and 20-30% (mass.) fractions (> 360°C). Among the by-products, 3.0-5.0% (mass) light hydrocarbon gases (0.5-1.0 mass %) and the coke residue are formed. According to their properties, the obtained liquid products can be used as components for the production of process and a boiler fuel or as additives to improve the low-temperature properties of commercial fuels. [ABSTRACT FROM AUTHOR]

Two methods were compared to select the optimum sample-preparation option for determining the heavy-metal contents in fatty oils. The first (GOST 26929–94) employed extraction of the metal ions from an oil sample by refluxing aqueous HCl solution. The second (European Pharmacopoeia, 8th Ed.) employed complex oxidative thermal destruction of an oil sample followed by processing in a mixture of conc. HNO3 and HCl with completion of the process by adding conc. H2SO4. The mineralization was carried out at high pressure in sealed Teflon containers with microwave heating. Extraction of metals from the weighed portions of fatty oils by HCl solution provided accurate and satisfactorily reproducible results. This method was shown not to require special apparatus and was expedient for determining metal impurities in fatty oils. Sample preparation using oxidative thermal destruction required the use of expensive equipment and was unsafe. [ABSTRACT FROM AUTHOR]

An overview of the ways of improving the operational properties of furnace and boiler fuels has been presented; their positive and negative features have been analyzed. It has been established that the most effective way to improve the operational properties of furnace and boiler fuels is their compounding with additives as well as various components since it is easy to implement under conditions of direct application of process fuel. It has been suggested that a very successful alternative to the additives and components used in industry can be fractions (components) obtained by thermal destruction in the temperature range of 300-380°C of secondary polymer raw materials, represented by polyethylene, polypropylene, and polystyrene. [ABSTRACT FROM AUTHOR]

The effect of additional heat treatment at elevated temperatures on the physicomechanical characteristics of unidirectional epoxy organoplastics has been studied. It has been shown that long exposure (24 h) at temperatures of 120 and 180°C leads to a significant decrease in crack resistance, as well as in the bending and shear characteristics of the composites under study. Infrared spectroscopy has revealed a tendency towards the formation of carbonyl groups after holding at 120°C. Possible reasons for the observed changes are discussed. [ABSTRACT FROM AUTHOR]

New magnetic nanomaterials with magnetization up to 32 Gs·cm3/g were synthesized from highly branched ferrocene-containing polymers by thermal structural transformations in a field of 2.5 kOe. The structure and properties of the prepared polymers were studied by IR spectroscopy, transmission electron microscopy (TEM) and thermogravimetric analyses. According to IR spectroscopy the content of 1,3,5-substituted benzene rings in the ferrocene-containing polymer increases at 500°C. X-ray diffraction study showed that iron in such a sample is present exclusively in the form of Fe3O4 magnetite. As the heating temperature increased to 600°C, the composition of the samples became more complex: along with magnetite they contain cementite Fe3C and wustite FeO.97O. The magnetization of the ferrocene-containing polymer depends on the synthesis and heat treatment temperature. For a sample synthesized at 140°C the formation of a magnetically ordered phase begins at 500°C, and at 800°C the magnetization reaches a maximum value of 32 Gs·cm3/g. The average size of magnetic particles according to TEM analysis was 8-26 nm. The principal possibility of controlling the size and composition of the nanoparticles, as well as their magnetization depending on the conditions of production and the temperature of polymer structuring is shown. The obtained results provide a good basis for the directed synthesis of magnetic ferrocene-containing polymers with preset characteristics.

The peculiarities of the thermal decomposition of the highly dispersed vanadium (IV) ammonium tetrabutanate salt, which is a precursor for the production of nanocrystalline vanadium oxides of different degrees of oxidation (V2O5, VO2), are studied. The purpose of experimental studies is to determine the influence of the parameters of thermal decomposition of ammonium tetravanadate on the processes of phase formation of nanocrystalline products of vanadium oxides (V2O5, VO2). Optical microscopy and powder X-ray diffraction investigates the dependence of phase-formation and the size of vanadium dioxide particles on the temperature of thermal degradation. Heat treatment of ammonium tetravanadate in an oxidizing atmosphere at a temperature of 400…500 °C leads to the formation of vanadium pentoxide (V2O5), the inert atmosphere contributes to the formation of vanadium dioxide (VO2) at 850…900 °C. The optimum temperature regimes of tetravanodate ammonium trim have been determined for the production of nanocrystalline vanadium dioxide with the phase transition present therein.

This work is the first attempt to study the physicochemical properties of ionogels - quasi-solid hybrid materials formed by ionic liquids (ILs) − 1-butyl-3-methylimidazolium (BMIm+) salts with dicyanamide- (DCA−), bis(trifluoromethylsulfonyl)imide- (TFSI−), and trifluoromethanesulfonate- (Otf−) anions - and halloysite, a powdered clay filler with nanotube particles (at the IL:Hal molar ratio of 2:1) in order to find possible new applications of ionic liquids and industrial minerals. The electron microscopy, TG, and DSC analysis, FTIR spectroscopy, X-ray diffraction analysis, conductometry and cyclic voltammetry methods are used to investigate the anion effect on the IL interaction with halloysite. It has, for the first time, been found that the distinguishing feature of halloysite interaction with an IL determining the structural changes in the clay mineral and electrochemical characteristics of the ionogels is partial dehydration of the clay and absorption of the released water by the ionic liquid. It is shown that the halloysite dehydration effect depends on the IL hydrophilicity determined by the anion type, corresponds to the series: BMImDCA > BMImOtf > BMImTFSI. The electrochemical and thermal behaviour of ILs confined within a halloysite matrix differs from that of bulk ILs and is controlled by the anion type. Temperature dependences of the structural resistance of the halloysite filler are radically different for the ILs with high and low hydrophilicity. The effects resulting from the formation of halloysite-based ionogels can be of interest to those who develop quasi-solid ionic conductors that can work within a wide temperature range. [ABSTRACT FROM AUTHOR]

Featured Application: The data presented in the article show the high efficiency of the superpulse thulium fiber laser for laser lithotripsy. We clarified the mechanism of action for the fragmentation of a stone phantom. Thulium fiber laser with a wavelength of 1.94 µm is widely used in urology for lithotripsy. This paper studies the mechanism of lithotripsy and evaluates its clinical efficiency using the superpulse thulium fiber laser with a wavelength of 1.94 µm and a peak power of 500 W. An experimental setup was developed to study the mechanism of lithotripsy. The superpulse thulium fiber laser (TFL) with a wavelength of 1.94 µm with a peak power of 500 W (FiberLase U2 from "IRE-POLUS" Ltd., Fryazino, Moscow Region, Russia) was used for the lithotripsy of stone phantoms (BegoStone). The processes were recorded with a high-speed camera. The acoustic signals registered during lithotripsy were studied with wideband and needle hydrophones. The main mechanism of lithotripsy performed by using superpulse TFL was thermal cavitation in the water-filled pore space and thermal destruction of the phantom. During the clinical application of the superpulse thulium fiber laser, the high efficiency of laser lithotripsy was established. The performed optical and acoustic studies showed that the mechanism of the destruction of stones was based on the synergic effect of the explosive boiling of water in the pore space of the stone, and its thermal destruction is associated with the heating of the stone to several hundred degrees with laser radiation. [ABSTRACT FROM AUTHOR]

It is established by the method of dynamic thermogravimetric analysis that bismuth dimethyldithiocarbamate (DMDTC), which protects a number of polymers from heat and light, accelerates the thermal destruction of polycarbonate (PC) based on bisphenol A and is, in this case, an initiator of the thermal destruction. The kinetics of the multistage process of the initiated thermal destruction of PC is modeled by the method of nonlinear regression analysis. The peculiarity of the proposed approach lies in estimating the parameters of the Arrhenius equation for each of the stages together for all temperature programs. It is shown that such an analysis allows us to avoid the limitations characteristic of the Kissinger (Kiss) and Kissinger–Akahira–Sunose (KAS) methods, which are traditionally used to determine the activation energies of thermal destruction of polymers. [ABSTRACT FROM AUTHOR]

The studies reported here have made it possible to determine the optimal ways of fire protection, in which the samples of modified complexite have reduced flammability. The sample with the ions of molybdenum (VI), treated with phosphoric acid, had the highest magnitude of oxygen index among five modified samples of the fiber. This is the most fire-protected sample, which contains three types of flame retardants: nitrogen (amidoxime groups of complexite, phosphorus (treatment with phosphoric acid) and molybdenum (VI). The obtained data indicate the chemical interaction of flame retardant with complexite. The morphology of fibers and the process of their destruction are influenced by the introduction of flame retardants. Scanning electronic microphotographs show the existence of a morphological change of the surface at modification of the complexite samples with flame retardant. The introduction of flame retardant into complexite affects the process of thermal destruction of the samples in the air and argon media. At the same time, the introduction of molybdenum (VI) significantly reduces the thermal stability of fibers. It is likely that processes of thermal destruction can be catalyzed by metals both in the air medium and in the argon medium. The magnitudes of order of reaction of thermal decomposition at the transition from a fiber sample treated only with acids to the samples of complexite containing molybdenum (VI) decreases up to 0.38. At the same time the values of activation energies E, kcal/mol, and the enthalpy of the process of thermal destruction of complexite ΔΗ, kcal/mole also decrease. The mechanical properties of fibers at the introduction of flame retardants into the fiber composition change insignificantly. Depending on the composition of flame retardants, rupture load decreases by 6–11 %, lengthening of the samples decreases by 6–16 %. Thus, there are some grounds to suggest that it is possible to create fibrous materials based on cellulose with predetermined properties of reduced flammability. [ABSTRACT FROM AUTHOR]

The plantations of energy crops (willow, poplar, miscanthus, etc.) ensure the production not only of efficient biofuels, but also improve the ecological state of the environment due to the intensive absorption of carbon dioxide from the atmosphere. Miscanthus is an effective raw material for the production of solid biofuels. The article presents the results of thermal analysis of biofuel from miscanthus and research on the influence of the fractional composition of raw materials, temperature and pressure of granulation on the thermal destruction of granular fuel. Samples of granules obtained by cold pressing, mechanical activation and thermal activation of raw materials are used in the work. Temperature intervals of dehydration, thermal decomposition of organic and mineral substances, average rates of thermal decomposition of organic compounds, humidity and ash content of biofuel samples were determined by thermogravimetry and differential thermal analysis. Stages of dehydration, thermal decomposition of organic compounds, accompanied by the removal of gaseous products, and decomposition of mineral substances are characteristic of all samples of granular fuel from miscanthus. The highest rate of release of gaseous substances was observed in granules from mechanically activated and thermally activated raw materials, the lowest – in granules from polydisperse fraction after cold pressing. It was found that mechanical activation and thermal activation of raw materials have an effect on the process of thermal destruction. The intensity of decomposition of organic matter increases. It was found that the mechanical activation of raw materials is the most significant factor influencing the kinetics of thermal destruction. In the granules, mainly with thermal activation of the material in the granulation process, microexplosions were observed in the high-temperature decomposition period during thermal destruction. [ABSTRACT FROM AUTHOR]

The results of non-catalytic thermal destructive processing of solid domestic waste at atmospheric pressure and temperature of 360°C, which are represented by products of low pressure polyethylene, are presented. The products obtained during degradation can be divided into fuel products (gas, liquid hydrocarbon fraction, coke residue) and fraction (with the beginning of boiling in the temperature range 200-320°C), which can be used in the production of greases. After the heat treatment and cooling of these fractions, a product with properties similar to NYCO 65 VASELINE (Technical petrolatum (GREASE)) can be obtained. For the production of plastic lubricants with other properties and a large temperature interval of application, a scheme has been proposed, it provides for the addition of fillers and additives of different functional purpose to the lubricant obtained. [ABSTRACT FROM AUTHOR]

The results of investigations of thermal reclamation of spent moulding sands originating from an aluminum alloy foundry plant are presented in this paper. Spent sands were crushed by using two methods. Mechanical fragmentation of spent sand chunks was realized in the vibratory reclaimer REGMAS. The crushing process in the mechanical device was performed either with or without additional crushing-grinding elements. The reclaimed material obtained in this way was subjected to thermal reclamations at two different temperatures. It was found that a significant binder gathering on grain surfaces favors its spontaneous burning, even in the case when a temperature lower than required for the efficient thermal reclamation of furan binders is applied in the thermal reclaimer. The burning process, initiated by gas burners in the reclaimer chamber, generates favorable conditions for self-burning (at a determined amount of organic binders on grain surfaces). This process is spontaneously sustained and decreases the demand for gas. However, due to the significant amount of binder, this process is longer than in the case of reclaiming moulding sand prepared with fresh components.

Complex compounds NiCl2·2HMTA·10H2O (1), CoCl2·2HMTA·10H2O (2), CoCl2·HMTA·4.5H2O (3) were prepared by the reaction of nickel(II) and cobalt(II) chlorides with urotropine (HMTA). Compounds 1 and 2 are isostructural, their structure corresponds to the earlier studied crystal structure [Ni(H2O)6]Cl2·4H2O·2HMTA. Thermal destruction of the complex compounds 1-3 was studied by TGA and high-temperature IR-spectroscopy. The TGA curve for compound 1 shows stepwise mass loss caused by two-stage loss of all water molecules (up to 170°C) and one urotropine molecule (up to 270°C) followed by decomposition of NiCl2·HMTA. The X-ray diffraction pattern of the resulting solid shows no reflections typical for the metal and its simplest nitrogen-, carbon- and chlorine-containing compounds. Thermal decomposition of сompounds 2 and 3 proceed similarly, but water is removed in one stage. IR spectra, which were recorded at high temperature (up to 220-230°C) show gradual decrease of intensity of the bands assigned to vibrations of water molecules. The bands of the methylene groups of urotropine do not change on heating. However, the bands of the C-N vibrations shift from ~1050 and ~1008 cm-1 in the spectra of urotropine and [M(H2O)6](HMTA)2Cl2·4H2O to 1015-1019 and 984-995 cm-1, respectively, indicating coordination of urotropine molecules instead of the removed water molecules. The long-wave IR spectra for NiCl2·6H2O and compound 1 at ambient temperature show bands of Ni-O stretching vibrations and O-Ni-O bending vibrations. After heating 1 at 115° C, bands of Ni-N and Ni-Cl appear, which indicates the coordination of urotropine molecules and chloride ions after the removal of outer-sphere and inner-sphere water molecules.

There is much interest in reducing hydrofluorocarbon (HFC) emissions due to their high global-warming potential. Many treatment technologies have been developed, including the plasma, catalytic, and thermal destruction of waste HFCs. From an economic perspective, existing facilities should be capable of ensuring their destruction, without the addition of more energy or after-treatment systems. Here, a high-temperature thermal destruction method for HFC-134a from end-of-life vehicles (ELVs) is presented at the pilot and full operating scales. The method involves reductive conditions in a laboratory-scale reactor and a gasification melting system. The destruction removal efficiency (DRE) increased as the reaction temperature and the normal stoichiometric ratio (NSR) increased in a laboratory-scale reactor. HFC-134a was completely destroyed at 950 °C, a residence time of 4 s, and NSR of 1.0–2.0. The optimum NSR was found to be 1.5 for this system. Based on FT-IR and GC-MS analysis, a removal efficiency of more than 99.99% was obtained in pilot and full-scale systems. HFC-134a was completely destroyed at the feed rates of 0.15, 0.375, 0.75, and 1.5 kg/h in a pilot-scale system. The atmospheric emissions, including dioxin, were shown to satisfy regulatory levels for the pilot and full-scale systems. This suggests that gasification-melting system can be useful tools for decomposition of HFCs and has the potential to be a practical process for the treatment of wastes from ELVs including not only the automobile shredder residue and but also refrigerants. • High temperature thermal destruction of HFC-134a from end-of-life vehicles (ELVs) is investigated. • The HFC-134a was completely destroyed in the pilot plant system using gasification melting. • The DRE value was more than 99.99% for the full-scale gasification melting plant. • The air pollution concentrations in flue gas, including dioxins, met the emission limits. [ABSTRACT FROM AUTHOR]

Background: We compared the differences in thermal damage at the surgical margin between monopolar cautery, bipolar cautery, and LigaSure™ in breast cancer lumpectomy specimens and assessed the effect of these techniques on the evaluation of the surgical margins. Methods: 30 patients scheduled for breast-conserving surgery for breast cancer were included in this study. During lumpectomy, each of the superior, inferior, lateral, and medial borders of the tumour was excised using one of the following: a scalpel, monopolar cautery, bipolar cautery, and LigaSure technology. The surgical margins of frozen and paraffin-embedded tissue sections of the lumpectomy specimen were evaluated. Thermal damage was defined as the maximum depth of thermal damage (in mm) from the surgical margin, and the level was categorized as none, low (≤1 mm), or high (>1 mm). Results: There was no statistically significant difference between monopolar cautery, bipolar cautery, and LigaSure in terms of thermal damage. There was no thermal damage at the surgical margin in tissues dissected by scalpel. Conclusion: Thermal damage due to the excision method may cause false-negative and false-positive results in the surgical margin evaluation of lumpectomy specimens. More research is needed on the effects of different energy modalities on surgical margin evaluation in breast-conserving surgery. [ABSTRACT FROM AUTHOR]

Thermal destruction of wheat grain processing wastes (WGPW) and the obtained products structure formation depending on the temperature of the carbonization process were studied. It is shown that the structural transformations of the wheat grain processing waste (bran) during the thermal treatment in the studied interval proceed through the stage of free radicals formation as a result of recombination. Hexagonal meshes of cyclically polymerized carbon are formed. The concentration of free radicals formed in this process, and X-ray phase composition of the graphitelike component of the obtained products are determined. [ABSTRACT FROM AUTHOR]

The influence of the composition of the mixtures of petroleum (fuel oil) and vegetable raw materials on the yield and composition of products formed upon the pyrolysis of the mixtures was investigated. Data on the pyrolytic transformations of the mixtures in a temperature range of 140–700°C are given. It was established experimentally that the yield of solid pyrolysis products decreases and the yield of gas and tar increases with the fuel oil content of the mixture. The yield of pyrolysis products also depends on the concentration of emulsified water in the mixtures. [ABSTRACT FROM AUTHOR]

The effect of boric acid (BA) on the thermal destruction of polyvinyl alcohol (PVA) was studied. The pyrolysis temperatures were chosen based on the thermogravimetric analysis data. The composition of the main products of pyrolysis was determined. The mechanisms of thermal destruction were proposed for PVA and its composite with BA. The observed phenomena associated with the effect of the filler on the composition of the products of PVA pyrolysis were explained. [ABSTRACT FROM AUTHOR]

Adhesion strength τ of joints of a fiber–epoxy matrix was studied upon multiple repetition of the curing process. It has been shown that recuring weakens the interface. After a 12-fold cure, the values of τ are reduced by 30%. The possible causes of the observed changes are considered. The fall of τ should be considered when designing products made of GFRP. [ABSTRACT FROM AUTHOR]