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Maple sap is a sterile liquid extracted from maple trees in early spring. However, it is rapidly contaminated during handling and processing. Typically, raw sap undergoes a reverse osmosis process for concentration; meanwhile, this operation also concentrates the microorganisms present in the sap. The enrichment of microorganisms affects the quality of the sap and its derived products remarkably. Consumption of concentrated maple sap as a novel natural soft drink has increased considerably in recent years, mainly in North America but also worldwide. Adequate processing is required in order to eliminate the microorganisms and stabilize the quality of the concentrated maple sap for further consumption. Thermal processing is a safe preservation technique; however, severe thermal processing may affect negatively the quality of the product for consumer acceptance. Therefore, it is important to evaluate the right thermal processing parameters such as D‐ and Z‐values for a given product. Spores of Clostridium sporogenes PA 3679 strain were used as a surrogate to evaluate the thermal destruction kinetic parameters of spores in concentrated maple sap (10°Brix–30°Brix) over a range of temperatures (90°C–105°C). Obtained D‐values varied from 6.57 to 0.35 min depending on the sap concentration and temperature with an average Z‐value of 7.84 ± 0.42°C. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses indicate that the spore cortex and core break down first during conventional thermal treatment as a result of heat transfer from the external media to the spore interior. The results of this study can be used by maple sap industries to design and perform a safe thermal process for pasteurization and/or sterilization of concentrated sap. It could also serve as a benchmark in the development of advanced green technologies such as ohmic heating. [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 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]

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]

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.

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]

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.

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]

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]

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.

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]

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]

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.

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]

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 results of investigations of spent moulding sands taken from the mould at various distances from the surface of the produced casting, are presented in the paper. The casting mould was made with an application of the cooling system of the metal core in order to increase the cooling rate of the ladle casting. As temperature measurements in the mould indicated the heat flow from the metal did not create conditions for the complete burning of a moulding sand. The analysis was performed to find out changes of spent moulding sands caused by degradation and destruction processes of organic binders. Conditions occurring in the casting mould were discussed on the bases of testing: ignition losses, dusts contents, pH reactions and the surface morphology of the moulding sand samples. Factors limiting the effective mould degassing were pointed out. Operations, possible for realization, which can limit the reasons of a periodical occurrence of increased amounts of casting defects due to changing gas evolution rates being the result of the technological process, were also indicated.

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.

The obtained results of heating of sand moulds with binders by means of a thermal radiation of liquid metal are presented in this study. Standard samples for measuring Rg made of the tested moulding sands were suspended at the lower part of the cover which was covering the crucible with liquid metal (cast iron), placed in the induction furnace. The authors own methodology was applied in investigations. The progressing of the samples surface layers heating process was determined as the heating time function. Samples of a few kinds of moulding sands with chemical binders were tested. Samples without protective coatings as well as samples with such coatings were tested. The influence of the thermal radiation on bending resistance of samples after their cooling was estimated. The influence of several parameters such as: time of heating, distance from the metal surface, metal temperature, application of coatings, were tested. A very fast loss of strength of moulding sands with organic binders was found, especially in cases when the distance between metal and sample surfaces was small and equaled to 10÷15 mm. Then, already after app. 15 seconds of the radiation (at Tmet=1400°C), the resistance decreases by nearly 70%. Generally, moulding sands with organic binders are losing their strength very fast, while moulding sands with water glass at first increase their strength and later slightly lose. The deposition of protective coatings increases the strength of the mould surface layers, however does not allow to retain this strength after the metal thermal radiation.

The paper presents possibility of using biodegradable materials as parts of moulding sands’ binders based on commonly used in foundry practice resins. The authors focus on thermal destruction of binding materials and thermal deformation of moulding sands with tested materials. All the research is conducted for the biodegradable material and two typical resins separately. The point of the article is to show if tested materials are compatible from thermal destruction and thermal deformation points of view. It was proved that tested materials characterized with similar thermal destruction but thermal deformation of moulding sands with those binders was different.

The results of the thermal destruction of solid domestic waste (which are polyethylene items) were presented for batch-type laboratory equipment. According to the modern requirements of EU for the amount of sulphur in fuel and boiler fuels, polyethylene items are a valuable source for production of these fuels. During atmospheric heating of the raw material in reactor the intensive destruction of polyethylene can be observed in the range of temperature 560-580 K. It has been defined the composition of products of polyethylene thermal destruction: 95 % (mass.) of liquid hydrocarbons, 4,5 % (mass.) of light hydrocarbon gases and 0,5 % (mass.) of coke. Fractionation of liquid hydrocarbons allows to separate 15 % (mass) of fraction 340-488 K, 14 % of fraction 406-518 K, 43 % of fraction 438-546 K and 27 % of residue (>623°C fractions). Liquid products can be applied for production of boiler and furnace fuels independently and in a mixture with the petroleum processing products in different ratio. [ABSTRACT FROM AUTHOR]

Abstract The results of studies of the nonlinear optical properties of dye-doped nematic (NLCs) and cholesteric liquid crystals (CLCs) under powerful laser excitation are presented. The invariability of the structure of a planar-oriented NLC as a result of the conservation of the absorption dichroism of an impurity dye under the control over the lasing threshold is shown. A method to reduce the threshold for the stimulated Raman scattering (SRS) in the isotropic phase of NLC at frequencies that overlap with the amplification band of a dissolved dye is proposed. The peculiarities of the energy characteristics of CLC lasers are studied in detail. A variation of the lasing efficiency and the nonlinear dependence of the lasing energy on the pumping are explained within a model of lasing systems with distributed feedback. The dynamics of the optical destruction of a planar texture of a dye-doped CLC at critically high levels of laser irradiation is studied. Highlights • Oriented textures of a LCs lasers are stable under pumping pulse intensity in tens of MW/cm2 and duration up to 100 ns. • The efficiency of a CLC laser depends on a thermal phase grating that arises from the presence of ordered dye molecules. • Dye-doped LC makes gain that permits recognition the vibrations of most faint transitions in stimulated Raman scattering. [ABSTRACT FROM AUTHOR]

A design for a neutralizer of industrial wastewaters that complemented power-, heat-, and water-supply systems of oil and gas enterprises was proposed. A scheme of a neutralizer with thermal destruction of effluents and gaseous and liquid combustible wastes and container disposal of the resulting dry residue was presented. Technical solutions that made it possible to achieve the lowest specific fuel consumption among known designs and to increase the energy efficiency and environmental safety of oil and gas enterprises were described. [ABSTRACT FROM AUTHOR]

The effect of nanodiamond filler on the thermal decomposition of polytetrafluoroethylene composites under vacuum pyrolysis was studied by means of thermodesoption mass spectrometry. The results indicate that the presence of nanodiamonds affects both the temperature profiles and the chemical composition of decomposition products.

One main problem in moulding is the proper characterization of the local density of the mould, the best without its destroying, for assessment the quality of the mould and to compare results of compaction modeling with experimental results. Industrial computer tomography (ICT) is a technique that allows the non-destructive and contact-free visualization and characterization of the internal and external parts of physical objects including also sand moulds. It is possible to apply ICT technique for the specific research presented here. Moulding sand compaction plays an important role for the quality of the mould and as the consequence for the quality of manufactured casting. The required quality of the castings can be achieved by selecting optimum manufacturing process parameters. The determination of these parameters is often carried out by trial-and-error-method, which is expensive and time consuming. To improve the understanding of the influence of various parameters, mathematical modeling of the compaction processes using numerical solutions was performed. Theoretical results of the compaction simulations have then been compared with practical results of mould compaction obtained by ICT. Itwasfound that simulation results agree well with data from computer tomography and provide insight into the spatial distribution of the density of sand moulds under industrial condition.

With the destruction of numerous coal seams around the world, coalfield fire is becoming a matter of global concern. This paper probes into the crack features of rock strata in a coalfield fire-stricken area, to answer to call for energy conservation and environmental protection. Specifically, the temperature variation was investigated through simulation experiments based on the coal seam model and rock strata model, and the crack development was qualitatively researched on the surface of coal seam and the overlying strata. The main conclusions are as follows. Comparing the temperature of measuring points on the same horizontal plane, it is concluded that the temperature of the coal seam above the heat source increased with the distance from the heat source within a certain range. The temperature diffusion was rather slow in coal and rock and the fire source movement was very time-consuming. The surface temperature variation of the overlying strata was similar to that of the fire source, indicating that the fire source could be roughly located by the surface temperature variation of the overlying strata. Meanwhile, the thermal destruction resulted from high temperature boosted the crack development in both coal seam and rock strata, and collapse occurred when the coal burned out. During the coalfield fire, the crack development was bolstered by the high temperature produced in the interaction between the crack field and the temperature field: besides, the cracks created a passage for oxygen supply, which favours the coal combustion. All in all, the coalfield fire development was enhanced by the interaction between the crack field and the temperature field. [ABSTRACT FROM AUTHOR]

A mathematical model for the numerical study of thermal destruction of the "Chelyabinsk" meteorite when entering the Earths atmosphere is presented in the article. The study was conducted in the framework of an integrated approach, including the calculation of the meteorite trajectory associated with the physical processes connected with the meteorite motion. Together with the trajectory the flow field and radiation-convective heattransfer were determined as well as warming and destruction of the meteorite under the influence of the calculated heat load. An integrated approach allows to determine the trajectories of space objects more precisely, predict the area of their fall and destruction.

We have offered the method of creation of the composition material on the basis of the molecular mixture of polytetrafluorethylene and TiO 2 by absorption of the products of thermal decomposition of polytetrafluoroethylene and ammonium hexafluorotitanate on ammonia water. The molecular distribution of TiO 2 in the structure of composite is well-proven by X-ray diffraction analysis. We have studied the influence of the entered connection on the yield of a titanium-fluorpolymeric composite in the gas phase. [ABSTRACT FROM AUTHOR]

The influence of temperature on the spectroscopic properties of powders and aqueous solutions of riboflavin was studied using NMR, linear dichroism, IR and UV absorption spectroscopy, and luminescence. It was found that exposure of riboflavin powders over a wide temperature range (290-423 K) did not change significantly its properties and spectral characteristics. The absorbance and fluorescence of aqueous solutions of riboflavin decreased under the same conditions due to riboflavin thermal destruction. The fraction of destroyed molecules in aqueous solutions of riboflavin was in the range 4-28% and depended on the drug concentration and thermal conditions. [ABSTRACT FROM AUTHOR]