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Thermal Methods of Analysis
... Thermogravimetric analysis showed that endothermic effects observed in the sample are associated with the release of hygroscopic and chemically bounded water, as well as the breakdown and dissociation of carbonates, and with the gradual breakup of minerals, including oxalates [51,52]. Exothermic effects are associated with the combustion of various plant residues typical of the bonitet of the studied area [53,54]. Whewellite (Figure 5a) was detected in the upper organic horizon of Skeletic Cryosol (Thixotropic) and in the form of a film on the surface of plant residues of Humic Fluvisols ( Figure 5c); therefore, there is a distinct exothermic effect in the range of 200-400 • C associated with the combustion of organic matter [54]. ...
... Exothermic effects are associated with the combustion of various plant residues typical of the bonitet of the studied area [53,54]. Whewellite (Figure 5a) was detected in the upper organic horizon of Skeletic Cryosol (Thixotropic) and in the form of a film on the surface of plant residues of Humic Fluvisols ( Figure 5c); therefore, there is a distinct exothermic effect in the range of 200-400 • C associated with the combustion of organic matter [54]. The additional endothermic effect in the samples taken on the Stagnic Cryosol Reductaquic (sample 984) (Figure 5b), Humic Fluvisols (Figure 5c), and siltstone (sample KM-6-21) (Figure 5d) in the area of 200-600 • C is probably related to the presence of other components (for example, iron hydroxides typical of soil and oxidized outcrops), not detected by XRD (Figure 3b-d), possibly due to their amorphous character [53]. ...
... The additional endothermic effect in the samples taken on the Stagnic Cryosol Reductaquic (sample 984) (Figure 5b), Humic Fluvisols (Figure 5c), and siltstone (sample KM-6-21) (Figure 5d) in the area of 200-600 • C is probably related to the presence of other components (for example, iron hydroxides typical of soil and oxidized outcrops), not detected by XRD (Figure 3b-d), possibly due to their amorphous character [53]. there is a distinct exothermic effect in the range of 200-400 °C associated with the combustion of organic matter [54]. The additional endothermic effect in the samples taken on the Stagnic Cryosol Reductaquic (sample 984) (Figure 5b), Humic Fluvisols (Figure 5c), and siltstone (sample KM-6-21) (Figure 5d) in the area of 200-600 °C is probably related to the presence of other components (for example, iron hydroxides typical of soil and oxidized outcrops), not detected by XRD (Figure 3b-d), possibly due to their amorphous character [53]. ...
The formation of oxalates in soils and rocks under conditions of cryoarid climate, permafrost and taiga vegetation was studied. Whewellite and weddellite were found in four areas associated with the mining industry: on the kimberlite deposit of the Daldyn territory, in the lower reaches of the Markha River of the Central Yakut Plain, and on the coastal outcrop of the Allah-Yun Sellah-Khotun ore cluster. Whewellite was found in the upper organic horizon of Skeletic Cryosol (Thixotropic) (sample 151) and as a film on the surface of plant remains of Humic Fluvisols (sample 1663). Weddellite was found as an extensive encrustation on the surface of the soil and vegetation cover of Stagnic Cryosols Reductaquic (sample 984) and on a siltstone outcrop (sample KM-6-21). Calcium oxalates were identified by X-ray phase analysis, photographs of the samples were taken on a polarizing microscope, and the crystal morphology was studied on a scanning electron microscope. To determine the chemical composition of soils and rocks, the classical wet-chemical method was used; the physical properties of the studied samples were studied using a pH meter, the photoelectric colorimetric method, and a synchrotron thermal analysis device. The source of calcium for the formation of salts is the parent layers of the studied soils, represented by carbonate and carbonate clastic rocks, which cause neutral and slightly alkaline environments. High humidity, which is provided by the seasonal thawing of the permafrost, has a key role in the formation of the studied oxalates in Yakutia with a sharply continental cryoarid climate. Based on the studies, it was found that the first two samples are the products of lichen activity, and the third and fourth are at the stage of initial soil formation by micromycetes. In addition, the formation of these oxalates, in our opinion, is the result of the protective function of vegetation, in the first two cases, with a sharp increase in the load on lichens under technogenic impact, and in the second and third cases, when favorable conditions arise for initial soil formation, but under conditions of toxic content of heavy metals and arsenic.
... On the other hand, it was the "Thermal Analysis Symposium" held at the Northern Polytechnic in London in 1965. The initial books published on both sides [35][36][37][38][39][40][41][42] became the basis for the growth of a newly emerging field that can be characterized at four different but gradually increasing levels: identity (fingerprints [43]), quality (such as characteristic temperatures [44]), quantity (peak areas) and kinetics (curve shapes). ...
... In its primary stages, thermal analysis researchers focused on the design and construction of devices, often prepared at home in laboratories from the parts available at that time [61], which was a frequent subject of early books [34][35][36][37][38][39][40][41][42]. The instrument application was focused on the area of fingerprints [43] and the identification of characteristic temperatures [31][32][33][34]44] for which it was necessary to undergo calibration of the instrument using the temperature behaviour of well-known standards [62,63]. ...
... Consequential from Fig. 1, the size of the area depends on whether we take the as-measured peak or its refined form after rectification. In the traditional kinetic approach of non-isothermal measurements, the first procedure is favoured conventional due to its historical roots [30][31][32][33][34][35][36][37][38][39][40][41][42] and the question arises as to how far the kinetic outputs would change after inertia implementation and whether this would invalidate previously published data. Yet another issue is the evaluation of overlapping peaks, which is used to identify interconnected and otherwise associated processes. ...
The review summarizes the current state, outlook and development of the field of thermal analysis, emphasizing the study of thermal effects as the basis of all other methodologies. Heat and its understanding intertwines throughout the entire civilization from the Greek philosophers through the middle ages to today’s advanced technological era. The foundations of the field of thermal analysis, where heat acts as its own agent, date back to the nineteenth century, and the calorimetric evaluation of heat fluxes became the basis. It views the processes of calibration and rectification specifies the iso- and noniso- degrees of transformation, explains the role of the equilibrium background, which is especially necessary in kinetics. It introduces a new concept of thermodynamics with regard to the constancy of first derivatives and discusses the role of standard temperature and its non-equilibrium variant—tempericity. It describes the constrained states of glasses and assesses the role of dimensions in material science. Finally yet importantly, it deals with the influence of thermoanalytical journals, their role in presenting unusual results, and discusses the role of the dissident science. It also describes the level and influence of adequate books and finally describes discussions and perspectives, i.e. where to look better interpretation for and what is the influence of current over-sophisticated devices.
... The studies on TGA-951 thermobalances were carried out in the dynamic mode of heating in an air atmosphere at heating rates of 5, 10, and 20 °C/min. 18,19 Thermoanalytical curves were processed using special software: File Modification V 1.0, General V 1.0 and TGAKin V 1.0, installed on the Du Pont 9900 thermoanalyzer; The Universal Analysis 2000 program of TA Instruments, Version V 4.0C (Intertech Corporation, Tampa, Florida, United States). ...
... x 0.2853 (17) while for the treatment with composition 2: y = 71.247 x 0.1556 (18) The results of the stepwise regression analysis are presented in Table 3. The initial data and the power regression model for "Pine + composition 1" and "Pine + composition 2" are presented in Figure 6 (a, b). ...
"For cellulosic materials used in various branches of the economy, the issue of increasing thermal stability is still relevant today. Especially acute is the problem of fire resistance for wood materials used in building structures. In our work, we investigated the effect of mono- and diethanolamine borates on the thermal decomposition of wood in an air atmosphere. It has been previously found that mono- and diethanolaminoborates, when used as surface modifiers, provide 100% biostability to plant raw materials. In this regard, the purpose of the study was to identify the flame retardant effect of the described modifiers. In the course of the study, it was found that the developed compositions, the main components of which are boron-nitrogen compounds, effectively reduce the combustibility of wood materials, suppress smoldering, and reduce the burning rate of wood. Since it is the smoldering of wood after the liquidation of the fire that is the main cause of structural collapse, which prevents evacuation during the fire, the use of the developed compositions for fire protection of wooden structures is extremely appropriate. A regression model of the dependence of activation energy on conversion has been obtained and substantiated on the basis of correlation and regression analysis. The presented semi-logarithmic model can be further applied to predict the dependence of the activation energy value of the thermal decomposition process of modified wood on the degree of conversion."
... According to the results of the separation of fractions according to the size of the psammitic (sandy) part of the sample, it was revealed that larger fractions predominate in the samples. Sample size modulus values vary from 1,40 to 0,96, respectively [8,9]. ...
... X-ray phase analysis of clay ( Figure 2) showed that it consists of quartz and montmorillonite, which are manifested by diffraction reflections with blurred areas in small and medium corners, and there is also an admixture of hydromica [8][9][10]. An important factor in the use of drilling waste is their radiological safety. ...
The relevance of the chosen topic is due to the need to solve environmental problems that arise when drilling oil and gas wells. The study is aimed at the disposal, neutralization and reuse of drilling waste, which will create a reserve of competitive raw materials for the production of bricks. The possibility of recycling a man-made product obtained in the process of drilling oil wells at the facilities of the Morozovskoye deposit (Krasnodar Territory) in the production of ceramic products, namely building bricks, is considered. A physical and chemical study of the drilling waste of the considered deposit was carried out, with the aim of its subsequent use in the raw mix for the production of building bricks. A comparative characteristic of the raw material composition, phase and mineralogical composition, as well as the plasticity number of drilling waste and clay from the Gubskoye deposit (Krasnodar Territory) is presented. On the basis of the data obtained, appropriate conclusions were made about the possibility of using drilling waste as a raw material component.
... To examine lipid and lipid carriers' "thermal behavior," a thermal gravimetrical analysis (TGA) and differential scanning calorimetry (DSC) are used. Melting point, crystallinity, and endothermal and exothermal characteristics of the sample are the main data generated by thermal analysis [109]. This technique involves samples being analyzed in unusual atmospheres consisting of nitrogen, oxygen, and argon warmed at a controlled heating rate. ...
... This technique involves samples being analyzed in unusual atmospheres consisting of nitrogen, oxygen, and argon warmed at a controlled heating rate. The thermal analysis can be easily predicted for phase transition, crystallization, and lipid sample amorphication by the enthalpy or entropy of the carrier system/ sample, which involves change in free energy in phase transition during thermal analysis [109,110]. ...
Various nanotechnology platforms have received notable attention in the field of medical biology, including diagnostics and therapy. In addition, research and development of engineered multifunctional nanoparticles as drug carriers has stimulated exponential development of applications in medicine. Lipid nanocarriers have been a very promising tool for the delivery of various drugs/therapeutic agents associated with solubility‐, bioavailability‐, and stability‐related issues. Lipid nanocarriers including liposomes, solid lipid‐based systems, self‐emulsifying drug delivery system, nanoemulsions, nanostructured lipid carriers, cubosomes and hexosomes, etc. are being very promising lipidic carriers to deliver several drugs, therapeutics nucleic acids, antibodies, proteins/peptides, or ligand targeted agents. Lipids‐based nanocarriers have the benefit of having exciting physicochemical behaviors such as higher bioavailability, least toxicity, higher drug loading, greater drug solubility, improved targeting effect of drug, etc. compared to others nanocarriers. This chapter includes the challenges and hurdles in lipid nano‐formulations and their application in drug delivery in various diseases. The chapter provides a brief description of advantage, types of lipid nanocarriers, their preparation method, characteristic properties, and characterization/evaluation methods including instrumentations and application in the nanopharmaceutical field.
... The energy of activation (E A ) of the thermal oxidative destruction of the synthesized LMPE-g-MAH samples is calculated by using Coats-Redfern method. 44 It was revealed that the dependence of the E A of thermooxidative destruction on the initiator concentration has a non-monotonic character (Fig. 6). ...
In this study, functionalization of low-molecular-weight polyethylene by melt grafting of maleic anhydride was investigated. The results reveal that initiator concentration, reaction time and temperature have the greatest influence on the graft degree. Structure of maleic anhydride grafted low-molecular-weight po-lyethylene was proven by FTIR, DTA and XRD me-thods. The grafted low-molecular-weight polyethylene has a potential application as a compatibilizer for mate-rials based on polyethylene compounds.
... Thermal Analysis Thermal analysis of the samples was recorded on a STA TG-DTA/DSC "Start-1600" (Linseis) by heating ~5 mg of samples at 10 °C/min in air atmosphere from ambient temperature to 700 °C. The results obtained by the TA method were used to calculate the crystallinity index of the polymer in composites [42], which was calculated based on the analysis of the DSC curves: ...
Composite materials filled with cellulose particles (microcrystalline cellulose and nanocellulose) have good prospects for use in various fields. Microcrystalline cellulose (MCC) and nanocellulose (NC) were isolated by chemical and physical methods and investigated. Composite materials based on polyethylene (PE) were ob-tained using MCC and NC as fillers (5–20 wt.%) and maleic anhydride grafted low molecular weight poly-ethylene (MA-g-LMPE) as a compatibilizer. The structure and morphology of the composites and fillers were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction, thermal analysis (TA), transmission electron microscopy (TEM), atomic force microscopy (AFM), and the strength properties were determined by tensile testing. An increase in the crystallinity index and mechanical strength of composites at low filler contents (up to 5 wt.%) was revealed. The size of the cellulose particles significantly affects the structure and properties of composites. Although the general picture of the effect of fillers on the crystalline structure and mechanical properties is similar, the addition of NC had a greater effect than МСС. The results of this study showed the possibility of using MCC and NC as reinforcement materials in composites, and they have biodegradable properties.
... For non-isothermal experiment, model fitting involves different models to α -temperature (α-T) curves and successfully determine Ea and A. There are numerous nonisothermal model fitting methods and the most popular one is the Coats and Redfern method [18]. This method has been most successfully used for studying the kinetics of dehydration and vaporization of different solid substances [19]. The kinetic parameters can be derived from modified Coats and Redfern Equation (1), ...
The kinetics and decomposition of a new spirooxindole compound, 2’-amino-6’-(1 H -indol-3-yl)-1-methyl-2-oxospiro[indoline-3,4’-pyran]-3’,5’-dicarbonitrile was studied by thermo gravimetric technique under non-isothermal conditions. The kinetic parameters were calculated using model-free (Friedman, Kissinger-Akahira-Sunose and Flynn-Wall-Ozawa methods) and model-fitting (Coats-Redfern) methods. The results of the Friedman isoconversional analysis of the thermo gravimetric data suggested that the investigated decomposition process follows a single-step.
... Applying the method of thermogravimetry allowed us to establish that the in uence of the growing season climate conditions on the proportions of the main polymeric components of early and latewood tracheid walls differs between B. tortuosa and Larix sibirica (Siberian larch) (Tyutkova et al. 2021). Ozawa-Flynn-Wall (OFW) and Broido kinetic models (Wendlandt, 1978; Baroni et al. 2016; El-Sayed et al. 2020) revealed a signi cant variability of the wood chemical composition in L. gmelinii and, with FTIR spectroscopy, crystallinity of cellulose of L. gmelinii early and latewood appeared to vary signi cantly in level (Tyutkova et al. 2017). ...
Woody vegetation growth conditions have marked effects on hemicellulose, cellulose and lignin formation. In this study, we analyzed the climatic responses of these major cell wall polymers in Betula tortuosa . We studied 35 annual rings (1980-2015) of B. tortuosa trees growing in the alpine forest-tundra of Kuznetsk Ala Tau using Fourier-transform infrared (FTIR) spectroscopy and pyrolysis gas chromatography mass spectrometry (Py-GC/MS). Our analysis of the correlation of the resulting spectra and Py-GC/MS values with mean air temperature and precipitation showed that the polymeric composition of B. tortuosa was mainly determined by June-August climate. The major factor limiting the development of the “unique” cell wall polymer composition of B. tortuosa found in alpine forest-tundra of Kuznetsk Ala Tau was a deficit of heat. At the end of the growing season, precipitation had largely a negative impact on polymer formation in B. tortuosa cell walls. We believe that combining FTIR spectroscopy and Py-GC/MS is an effective approach to quantifying the consequences of current climate trends for Siberian forest ecosystems.
... The thermodynamic parameters of the activated complexes are often calculated using the peak temperature Ts (maximum differential thermogravimetric peak) so that the value of ∆G*, H* and S* correlates with the highest rate of the process. Negative values of ∆S* indicate that the activated complexes have more ordered structures than the reactant [40]. The enthalpy activation, ΔH * , and Gibbs free energy, ΔG * , were calculated from; ΔH * = E * -RT and ΔG * = ΔH * -TΔS * , respectively. ...
The alloxan as a biomolecule ligand has been utilized to synthesize thermodynamically and kinetically stabilized four new tin(II), uranyl(II), vanadyl(II), and zirconyl(II) complexes. In the complexes, tin(II) ion present is in tetrahedral arrangement, zirconyl and vanadyl(II) ions present are in square pyramid feature but uranyl(II) ion present is in octahedral arrangement and all are coordinated by two bidentate alloxan ligand in complexes. The synthesized alloxan ligand coordinate with central metal(II) ion through oxygen in position C2=O and the nitrogen in position N1 developing a 4-membered chelate ring. Synthesized Sn(II), UO2(II), VO(II), and ZrO(II) complexes via bidentate ligand have been accurately described by various spectroscopic techniques like elemental analysis (C, H, N, metal), conductivity measurements, FT-IR, UV-Vis, 1H-NMR, and TGA. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS* and ΔG* were calculated using Coats and Redfern and Horowitz and Metzger equations. KEY WORDS: Alloxan, Metal ions, Spectroscopy, Ligand, Coordination, Thermogravimetry Bull. Chem. Soc. Ethiop. 2022, 36(2), 373-385. DOI: https://dx.doi.org/10.4314/bcse.v36i2.11
... For this analysis, Mass Spec and FTIR tools are usually used. In addition to a reaction, energy or reactant may cause immediate changes in the off-gas [9]. ...
Thermal analysis techniques are used by different authors for their research data
analysis process. Thermal analysis techniques are used to analyze the temperature
changes in samples. In this article six most widely techniques are discussed. Their
brief description, images, and principles are explained. The whole article is
effectively arranged to provide effective information regarding thermal analysis
techniques.
... There are two integration methods for solving gas-solid reaction kinetics: Coat-Redferm method and Metzger method [49][50][51]. This article uses the Coat-Redferm method for integral transformation: ...
A deep understanding of behavior about coke in the blast furnace for smelting Bayan Obo Mine is significantly important to guide its efficient smelting. The feed coke and tuyere coke were taken from 4# blast furnace in Baotou Steel as the research object. The differences in ash content, microscopic crystal structure, functional group, microscopic pore structure and alkali metal content were compared and analyzed. Then the behavior of coke in the blast furnace for smelting Bayan Obo Mine was obtained. The results show that the coke in the blast furnace undergoes a gasification reaction during the descending process, the chemical bonds are broken, the reactivity is improved, and the strength after the reaction is reduced. There are honeycomb-like pores on the surface of the tuyere coke, and the distribution of pore is uneven. In particular, the coke matrix eroded by slag and iron has rough pore walls, and the pores appear to merge. Alkali metals are enriched in the tuyere coke, the content of alkaline oxides is increased, the temperature of the violent reaction is decreased, and the activation energy of the reaction is decreased. The half-width of the (0 0 2) diffraction peak corresponding to the tuyere coke graphite carbon is sharply reduced, the flat peak disappears, and the peak shape is sharp. The grain size increases, the crystal structure tends to be ordered, and the degree of graphitization increases.
... These changes in energy and mass can be measured by thermogravimetry (TG), derivative thermogravimetry (DTG), differential thermal analysis (DTA) and differential scanning calorimetry (DSC), which make it possible to obtain information such as changes in the crystalline structure, reaction kinetics, melting and boiling point, glass transition, and others [60]. Changes in mass as a function of temperature and/or time [61] and continuous registration of mass subjected to heating or cooling [62] are definitions attributed to thermogravimetry. ...
Gums, or polysaccharides, are complex carbohydrates, soluble in water, which can form gels and mucilages. They have high molar mass and can be formed by galactose, arabinose, rhamnose, xylose, galacturonic acid, among others. They have gelling characteristics, thickening, moisture retention, emulsification and stabilization. Polysaccharides are widely used in the formulation of food products, due to their wide versatility. Its diversity of applications is closely linked to its chemical structures. The characterization of structural molecules allows the knowledge of the properties of polysaccharides or glycoconjugates. In this sense, this chapter addresses knowledge about chemical, molecular, rheological, thermodynamic characteristics that are extremely important to identify the use and applications of polysaccharides in the context of elaboration and innovation in the food industry.
... As the heating rate is increased, the global processes (19) of decomposition shift to higher temperatures, and the various pyrolytic reactions tend to overlap, or coalesce, as discussed by Wendlandt (20) and Mackenzie and Mitchell (21). Resolution of the different events becomes more difficult as the heating rate is increased, but, even so, it has been possible to follow this shift for the exotherm (# 5), the inflection point (# 4), and the average of the three endotherms (# 1, 2, and 3) as shown in Figure 3. ...
The differential thermal analysis of reconstituted tobacco sheet heated at rates of 0.1°C/s to 500°C/s in an inert atmosphere is reported. As the heating rate is increased, the characteristic temperature of each global process observed is increased. Using a non-isothermal first-order kinetic equation, the activation energies and frequency factors are obtained for these bulk decomposition processes
... There are numerous non-isothermal model-fitting methods, and the most popular one is the Coats and Redfern method [20]. This method has been successfully used for studying the kinetics of dehydration and decomposition of different solid substances [21]. The kinetic parameters can be derived from the modified Coats and Redfern Equation (1), ...
... In the course of experimental studies, the TG and DTG curves of changes in the sample weights and the rates of weight changes depending on temperature were obtained for the lowland peat (Fig. 1a) and the high-moor peat (Fig. 1b). For both types of peat, the profiles of the TG and DTG curves were similar to each other; the temperature and amplitude of peaks corresponding to a thermal effect gradually increased with the rate of heating, which is consistent with published data [27,28]. The DTG curves exhibited two extremum points at temperatures of 340 and 430°C for lowland peat (Fig. 1a) or 310 and 450°C for high-moor peat (without considering the drying process) (Fig. 1b). ...
The thermal decomposition of two types of peat from the Vladimir oblast of Russia in an inert
atmosphere of argon was studied for the first time with the combined use of thermogravimetry, Fourier transform
IR spectroscopy, and kinetic analysis. The majority of gaseous products (CO2, CO, and CH4) were
released at the main stage of pyrolysis at a decomposition temperature of 150–540°C, which was accompanied
by the greatest weight loss. As a result of thermal decomposition, the predominant portion of the organic
matter of peat passed into a gas phase. The Ozava–Flynn–Wall integral isoconversion method and the Criado
method were used to calculate the kinetic parameters of the thermal decomposition of peat and to determine
the mechanism of decomposition, respectively. The activation energies of peat varied in a range of 54–
271 kJ/mol, and heat transfer occurred through three-dimensional diffusion.
... Therefore, we can include this instrument within the group of non-differential calorimeters [8]. Besides, this instrument is outside the standards of calorimetry [9,10] as the studied process is not within the calorimeter and consequently is not isolated from external disturbances. ...
A calorimetric sensor for medical application has been developed to measure surface and localize heat dissipations of human body. The instrument evaluates the heat flux transmitted by conduction, through a thermopile, between the human body surface and a programmed thermostat at a set temperature. In this work, a model with twelve transfer functions describing the operation of the sensor is exposed. This model relates the inputs to outputs of the system. Sensitivities, poles and zeros of each of the transfer functions are obtained with two independent experimental measurements and a numerical optimization method based on the adjustment of the experimental output curves with the ones calculated by the model. The model simulates the operation of the sensor, determines its operating limits and assesses the flow of heat between human skin and the thermostat sensor. The proposed method is applicable to any non-differential calorimeter.
... In 1891 In the beginning, DTA could not be classified as a calorimetric method since no heat was measured quantitatively (Wendlandt 1964 and thermal diffusivity (Höhne et al. 2013). Hence, the ones we need to obtain the conductivity. ...
The Ferritic-Pearlitic (FP) steels are widely used in automotive and generally in engineering industry. Even if steels with FP structure are among the most common materials, they are not at the very least the easiest materials to machine. Many study researches have been undertaken on the inclusion contribution in the machining processes, but further investigation is required. More precisely, the machining performance appears to be highly dependent on the microstructural parameters. That is why in this research project this kind of steels were analysed in terms of its microstructural features. Five steel grades have been manufactured in four different microstructure variants regarding ferrite and pearlite percentage, hardness, interlamellar space of pearlite, grain size of ferrite and the aspect of pearlite (band or globular). The main goal of this research work is to understand the influence of FP steels microstructure in the broaching process. To do so, several specific goals have been defined: (i) characterization of the FP steels obtaining their microstructure, mechanical features (including flow stress) and thermal characteristics, (ii) friction identification depending on the microstructural parameters, (iii) experimental results of forces, roughness and chip thickness depending on the FP steel microstructure and (iv) development of a Finite Element Model able to simulate the broaching process and predict the experimental outputs.
... 4H 2 O → [Cu(L)(H 2 O)] · 2H 2 O + 2H 2 O↑ [Cu(L)(H 2 O)] · 2H 2 O → C 7 H 6 N 3 OS↑ + CuO↓ (polluted with carbon atoms).3.9. Kinetic StudiesIn literature studies, there are number of kinetic thermodynamic equations[18][19][20][21][22][23][24][25][26] have been utilized to analyzing a TGA curves, both the Coat and Redfern[20] and approximation Horowitz and Metzger[23] are a commonly methods. The kinetic diagrams and the collected ...
Mn(II), Fe(III), Co(II) and Cu(II) Schiff base complexes with general formula ML ⁻² . n H 2 O (where M is a respected metal ions and L ⁻² is the Schiff base). The Schiff base (L = TSCPA) was formed by the condensation of thiosemicarbazide and phthalic anhydride in acetic acid. The microanalytical analysis confirmed the 1:1 (metal: ligand) molar ratio. Magnetic susceptibility and electronic absorption spectra were suggested that the Fe(III) and Co(II) complexes were octahedral structure but the Mn(II) and Cu(II) complexes were tetrahedral geometry. FTIR spectra reveal that the ligand exists, predominantly, as keto form in a solid state but as enol form in the alkaline medium. The coordination between TSCPA chelate and central metal ions take place through nitrogen –NH, sulphur C = S and oxygen –OH groups. Based on the molar conductance measurements the complexes may be formulated as [Mn(L)(H 2 O)] · 4H 2 O, [Fe(L)(Cl)(H 2 O) 2 ] · 2H 2 O, [Co(L)(H 2 O) 3 ] · 3H 2 O and [Cu(L)(H 2 O)] · 4H 2 O due to their non-electrolytic behavior. The Schiff base ligand and their metal complexes were screened in vitro against G(+Ve) and G(−Ve) bacteria. This study came after proactive step, which concerning with docking study against pathogen proteins corresponding to microorganisms for bacteria and fungi, which will be scanned in vitro study. Thermogravimetry (TGA) and differential thermogravimetry (DTG) were discussed.
... Stearic acid (ΔH ref = 198.9 J/g) was used as a standard reference substance (Wendlandt, 1974): ...
The aim of this study was to analyze the impact of pulsed electric field (PEF) pre-treatment of apple tissue on kinetics of freeze-drying preceded by vacuum freezing and physical properties of such processed material. PEF intensified freeze-drying kinetics and thus reduced processing time by 57% in comparison to untreated apples slices. Furthermore, the effective water diffusion coefficient increased by 44% as a result of PEF application. Water activity changes during storage of freeze-dried apple tissue were more evident in the case of untreated material albeit initial water activity was higher in the case of electroporated samples. As proved by thermal properties measurements these differences were linked to higher crystallinity of the PEF treated samples (35.5%) in comparison to the untreated material (11.0%). The freeze-dried fruits subjected to PEF pretreatment absorbed more water than the untreated samples while no changes were observed for hygroscopicity and loss of the soluble solids during rehydration.
Industrial relevance
Obtained results confirm that application of pulsed electric field before freeze-drying makes possible to obtain high quality freeze-dried product preceded by vacuum freezing performed inside freeze-dryer which could reduce freeze-drying time. Since the rehydration capacity of PEF treated material, expressed as ability to absorb water, is better than untreated samples the application of this method could be beneficial when designing instant products. Performed research indicates also that PEF treated freeze-dried apples exhibit better stability expressed by water activity which in turn is related to crystallinity. What more, higher crystallinity of PEF pre-treated freeze-dried samples not only complements the explanation of different physical properties in comparison with intact freeze-dried material but also suggest that sensorial properties may vary.
... The ignition temperature t ig is determined for two parallel measurements with subsequent calculation of the mean. To determine the kinetic parameters, the results of thermal analysis in nonisothermal conditions are employed [7,8]. We make the following assumptions. ...
... The temperature and amplitude of the peaks corresponding to the thermal effect gradually increase with the increasing heating rate, which is confirmed by the data [23,24]. In addition, with a low heating rate, the system provides a large instantaneous thermal energy, and the purge gas during the experiment requires additional time to reach equilibrium with the furnace temperature. ...
In the article a comprehensive study of thermotechnical and thermogravimetric properties of peat from Vladimir region of Russia for power generation was carried out. Analysis of thermotechnical data showed that the samples under study of valley peat and high-moor peat are low-grade fuel and unsuitable for combustion due to high moisture and the need for preliminary drying of peat raw materials. Analysis of thermogravimetric data showed that the thermal decomposition of samples under study in an inert medium proceeds in 2 stages: evaporation of moisture and volatile yield due to the active decomposition of organic substance. At the same time, the average residual mass for valley peat is about 44%, for high-moor peat 35%; therefore, as a result of decomposition, most of the organic matter turns into a gas or liquid phase. Taking into account the obtained results, the use of peat for power generation is possible by use of various types of thermochemical conversion of peat raw materials like a pyrolysis/gasification to produce liquid, solid, and gaseous products, as well as processes for the production of solid composite fuels (briquettes). These technologies will make it possible to process low-grade fuels into peat products and thereby to expand the use of peat raw materials in power engineering.
... The temperature range of 25e600 C was used. The DTA and TGA curves of the samples were obtained to verify the profile of thermal decomposition (Wendlandt, 1974). ...
Purpose
The purpose of this paper is to use Amazon River shrimp meal and cassava flour as the raw materials for the production of an extruded product. Both these raw materials are highly consumed foods in the northern region of Brazil, but are not processed industrially, only being used for local consumption and there is little in the literature concerning their use.
Design/methodology/approach
The study was carried out using a full 23 factorial central composite rotational experimental design with three independent variables, which were shrimp meal; feed moisture content and temperature, with four replicates at the central point and six axial points. The dependent variables were: expansion index (EI), bulk density (BD) and specific length (SL). The principal component analysis (PCA) was applied for the sensory analysis.
Findings
Almost all the parameters studied had a significant influence (p<0.10) on the responses analysed. The product was well accepted by 78.11 per cent of the volunteers. Increases in the shrimp meal and feed moisture contents strongly influenced the physical analyses (EI, BD and SL) of the extruded product. In the application of the PCA for the sensory analysis, the influence of the variables aroma, appearance and purchase intention corresponded to PC1, and that of the variables flavour, texture, global acceptance and colour to PC2.
Social implications
The development of a product based on animal protein which is more available than common snacks, as a way of reducing the negative environmental impact caused by the disposal of Macrobrachium amazonicum, which is considered as accompanying fauna to artisan fishery.
Originality/value
The originality of this paper lies in the quest for the development and/or application of technologies that allow for the use of raw materials from the Amazon as a way of aggregating value to the existing wealth of this region.
For the first time, a method has been developed for the synthesis of aromatic imides of citraconopimaric acid by the interaction of primary aromatic amines (aniline, p-toluidine) and citraconopimaric acid in p-xylene at reflux. New aliphatic imides have been synthesized by the reaction of citraconopimaric acid and primary aliphatic amines (octyl-, octadecylamine) in a melt at 125–150°C. For the first time, the synthesis of citraconopimaric acid imidoamides was developed by treating citraconopimaric acid N-octylimide with thionyl chloride and subsequent reaction of the resulting acid chloride with primary aromatic amines (aniline, p-bromoaniline). A method has been developed for the synthesis of aliphatic imides of the rosin-citraconic adduct (in the form of technical products) by its interaction with primary aliphatic amines (octyl- and octadecylamine) at 180–200°C for 8–12 hours.
Together with Belarusian state technological university, the relationship between the structure of imides of rosin-citraconic adducts as modifiers of unfilled and filled industrial rubber compounds was studied, and the obtained additives were found to improve the technological properties of compositions while maintaining, and in some cases improving physical and mechanical parameters (increasing the resistance of compositions to thermal aging, bond strength of the cord with rubber, etc.).
The production of ceramic products is one of the most material-intensive industries. The relevance of research is based on the need to develop new modern technologies and methods for the production of facing ceramic bricks, expanding the range of produced building ceramics, by introducing man-made waste into the composition of the ceramic charge. This is due to the annual increase in the volume of various non-recyclable industrial wastes, which can serve as cheap raw materials and modifiers that improve the properties of ceramics in some cases, and the depletion of natural clay raw materials used in the ceramics industry, which is an acute economic problem, as it affects the quality and cost. manufactured products. The study is aimed at the recycling and reuse of man-made waste, which will create a reserve of competitive raw materials for the production of facing bricks. The methods of utilization and processing of production wastes were studied, the advantages and disadvantages of each were identified, and the most optimal method was chosen, which was introduced into the technology of manufacturing ceramic facing bricks.
With the continuous development of battery technology, there are new research investments in materials of various parts. In the field of electrolytes, ionic liquids (IL) are considered to be excellent electrolytes and have been widely studied in distinct energy fields. However, it is necessary to pay attention to the safety characteristics of ionic liquids at high temperature due to the application of energy. Still, there is little research on the reaction and kinetics of ionic liquids. To ensure the safety of ionic liquids, such as high temperature, the common ionic liquid 1-hexyl-3-methylimidazolium nitrate ([Hmim] NO3) was selected for analysis. The exothermic mode is obtained from the data of differential scanning calorimetry. The basic reaction parameters of [Hmim] NO3 were determined with thermodynamic equation simulation. For ionic liquids in the actual situation, consider adding a heat balance model to estimate its temperature change pattern and determine the hazard temperature and related safety parameters. Temperature changes were assessed by constructing 25.0 g and 50.0 g packages to simulate material reactions and heat transfer in the external environment. The results showed that [Hmim] NO3 had shorter TMRad and TCL (< 1 day) when the temperature was above 200 °C.
Superactive carbon (SAC), having a high surface area of over 2500 m²/g, could be a superior choice for many applications. However, the manufacture of SAC in bulk quantities is challenging. To demonstrate the possibility of SAC manufacturing in large amounts, a techno‐economic assessment was performed. For that purpose, a new method utilizing a mixture of waste lignin, KOH and KCl was employed. The chemicals were recovered after use. The technical assessment was performed based on laboratory‐scale experimental findings, a simplified process diagram, and mass and heat balance calculations. The economic evaluation was assessed through the estimation of capital costs (CAPEX), operational costs (OPEX) and the minimum selling price (MSP). Moreover, to demonstrate the potential costs saving for the water treatment process, the performance of SAC for the removal of natural organic matter was compared with that of commercial active carbon. SAC was obtained at a minimized KOH amount (1 g/g) and chemicals were successfully recovered with a rate of 5–10% losses. The CAPEX, OPEX and MSP were found to be 4–21 million EUR, 1–9 million EUR/year and 4.4–2.9 kEUR/t for a 0.5–5.0 t/year production capacity, respectively, at a profitability requirement of 20% and a less than 5 year payback period. In addition, SAC demonstrated considerably higher adsorptive capacity for natural organic matter (600–900 mg total organic carbon/g) compared with commercial active carbon (40–50 mg total organic carbon/g), which could lead to substantial process savings. SAC manufacture through this method has been validated and the benefit for the potential application is sufficiently clear to promote the successful commercialization of SAC using lignin wastes. © 2022 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.
This Newsletter originates from the request to explain how to work with pure DTA data, when only the difference between sample and reference temperatures is available as a differential response. Sometimes, this is enough to get a rough preliminary idea about the transformations in the sample. For more detailed information, especially when the goal of the study is to obtain the kinetics of a chemical reaction, data on the amount and dynamics of energy release are mandatory. Therefore, the researcher eventually comes to the necessity of calibration.
Although this topic is well known, it seemed not unreasonable to give brief recommendations on DTA calibration. Thus, the 20th, anniversary issue of the CISP Newsletter appeared.
Current aspects of the developing of modern self-shielding flux-cored wires composition for arc welding of low-alloyed steels are considered. Advantages and disadvantages of flux-cored wires of carbonate-fluorite, oxide and oxide-fluoride types of are shown in comparison. The effectiveness of gas shielding of molten metal at welding with self-shielding flux-cored wires of carbonate-fluorite type is analyzed considering the thermal properties of their cores. It is shown that to improve reliability of gas shielding at welding using the wires of this type it is important not only to ensure generation of sufficiently large volume of shielding gases at thermal destruction of the wire core, but also to control this process, providing gas evolution at all stages of heating and melting of the wire. The results of complex thermal analysis of the wire core mixtures containing, for example, lithium carbonate show substantially large heat losses for heating and melting of the wire core, which are accompanied by the development of energy-intensive processes of thermal destruction of core components. It is shown that the limitation of lithium carbonate content in the wire at the level of not more than 2 wt. % allows not only to preserve welding arc burning stability at the acceptable level but also to provide effective gas shielding of molten metal and easy separation of slag crust. The control of thermochemical reactions in the core is achieved by selection of its proper composition to ensure favorable melting of flux-cored wire and electrode metal transfer to the welding pool. Results of metallographic examinations of distribution and composition of non-metallic inclusions in metal of the welds made with wires of the oxide and oxide-fluoride types are presented. Main properties of the developed self-shielding flux-cored wires and recommendations on welding are given in conjunction with prospective fields of their application.
Drug excepient interaction , molocular level , using sofosticated tecniques
DSC, FTIR, X-ray diffraction
Here, we synthesized new thiazole complexes from Cu (II), Fe (III), and Pd (II) ions. Such complexes were characterized to present their chemical formulae, firstly. The octahedral geometry was suggested for the investigated complexes except Pd (II) complex (ARPTPd), which has a square‐planer arrangement. ARPTPd was planned to be used as a catalyst for synthesis of dihydrotetrazolo[1,5‐a]pyrimidine derivatives at mild conditions. The catalytic activity of ARPTPd complex in four‐components reaction approach was deliberately monitored till it reaches the most favorable conditions. The advantages of suggested catalyst were basically summarized by using green solvent (H2O), lower reaction time, and high products yields. Also, the superiority of ARPTPd complex and ultrasonic irradiation towards synthesis of dihydrotetrazolo[1,5‐a]pyrimidine derivatives was revealed compared with other Lewis acids, basic, and ionic liquid catalysts. Furthermore, the mildness of conversion and compatibility with different functional groups makes it attractive. In addition, in consecration, computational aspects were often taken according to their effect on the declaration or discrimination of variable functional characteristics. Crystal packing systems of complexes were configured to extract important surface properties. DFT study was also applied to explain the causes behind the superiorly of ARPTPd complex. Also, the optimization process for intermediates was executed to support the suggested mechanism. Finally, this simple, economical, and green catalytic procedure may be applied to the industry in future. Summary of catalytic reaction stepwise to produce Dihydrotetrazolo[1,5‐a]pyrimidine.
In the field of thermoanalytical kinetics, which is widely used, basic questions arise regarding a possible description of the effect of heat transfer and subsequent thermal inertia. Current practice still uses a simplified interpretation of directly measured data for an inert sample at a constant temperature rise to describe the studied reaction, which leads to a simplified reaction conversion ratio, which is further used for various mathematical processing. The analysis of the introduced rectangular heat pulses and their indication by DTA clearly shows that the effect of thermal inertia is fundamental and not negligible. This is, after all, known from calorimetry, where the integral constant of inertia has historically been used to calibrate the descending temperature, but it cannot generally be applied to the whole temperature process due to its nonlinearity. In the case of parallel processing, for example by gradually increasing the heating rate, the effect of thermal inertia can be partially compensated for each other which have yet to be confirmed. However, for the kinetic analysis of a single peak, it is necessary to adapt to the effect of the thermal delay due to thermal inertia, which, similarly to the measured enthalpy, is tied to the sample size. Of course, it will be up to the researcher to find a solution that also includes the effect of heat transfer and dissipation, which should become the main principle of thermoanalytical methods of the future, as shown by current examples combining thermal processes with their specific kinetics.
Biodiesel is an alternative to fossil fuels for diesel engines, yet actual biofuel properties need to be tuned to comply with fuel standards. In particular, fuel stability is required for efficiency and commercial use. Fuel stability varies with the nature and proportion of chemical functional groups of biodiesel. Optimum oxidation stability is required because degradation by oxidation gives products that compromise fuel properties and impair fuel quality and engine performance. For instance, oxidation induces the formation of short-chain corrosive acids and deposits. Here, we review techniques to improve the oxidation stability of biodiesel. For instance, stability is improved by additives such as antioxidants. Factors influencing oxidation stability include composition of fatty acids, acid content, peroxide content, iodine content, viscosity, insoluble impurities, external conditions, and storage material. Antioxidants reduce lipid peroxidation at the beginning of the chain reaction and increase the onset temperatures.
Series of Co (II), Cu (II), Zn (II) and Sn (II) complexes derived from thiosemicarbazide ligand (HTSC), was synthesized by environmentally favorable method (electrochemical). All isolated complexes, were deliberately characterized by available analytical and spectral tools. The proposed molar ratio was 1:2 (M:L) as the only isolated one, beside the significant contribution for solvent molecules. The octahedral configuration was proposed for all complexes. Conformational analysis was implemented using advanced program to determine the best structural forms for complexes. Moreover, essential parameters were calculated to export important features for studied complexes. Meanwhile, Hirshfeld crystal surface properties, were interested to illustrate strength of packing interaction forces. Furthermore, distinction of site types inside the molecule and their H‐donor or H‐acceptor ability. Antimicrobial study was conducted against different microorganisms, to assert on the importance of new complexes in therapeutic field. Furthermore and to strengthen the study, the inhibition simulation was performed with respect to all complexes against selected pathogen proteins. Essential interaction data, were exported for each docking process, to classify inhibition efficiency. Co (II) and Cu (II) complexes were the complexes that played well in therapeutic simulation treatments against Bacillus subtilis (1bn8) and Candida albicans kinase (4c0t) proteins. Some characteristics for Co(II) and Cu(II) complexes
This study focuses on the physico‐chemical characterization of an alginate extracted from seaweed (Padina pavonica) collected on the Tunisian coast. Since alginates display a broad variety of applications, especially in the food and pharmaceutical fields, their quality requires a high certain standard of purity and an accurate knowledge of their composition and structure. With this aim, once extracted the Na‐alginate was purified and then characterized for comparison with a commercially available alginate. Thermal analyses (TGA and DSC) were performed to evaluate the water content, i.e. the moisture loss and the thermal stability of this polysaccharide. Spectroscopic investigations demonstrated similarities but also significant differences between the two samples. NMR spectroscopy enabled determination of the mannuronic/guluronic (M/G) ratio, which happened to be lower for the alginate extracted from P. pavonica algae. SEC, performed in water as eluent, was implemented for determination of the average molecular weight of these water‐soluble polymers and revealed 6‐fold higher molecular weights (Mn and Mw) than the commercial reference. © 2020 Society of Chemical Industry
New triazole‐derivatives were synthesized and characterized (spectral, analytical and conformational). After that, the new derivatives were coordinated with VO (II) atom to prepare new series of complexes. Distorted octahedral and square‐pyramidal geometries, were the geometries suggested based on UV‐ Vis and ESR spectra. A neutral poly‐dentate mode of bonding was proposed by 1:1 (M:L), for all complexes. TGA study supports the molecular formula of VO (II) complexes as well as, mass spectral‐analysis that executed for examples. The isotropic, anisotropic, molecular orbital and Hamiltonian parameters were estimated upon ESR spectra, for selected complexes. XRD patterns were executed for three complexes, two among appeared with particulate‐sizes in nanometer‐range. Conformational study was executed for all synthesizes applying RTD‐B3LYP‐FC method. Essential physical parameters were estimated and discussed. MOE‐docking that considered a bright part, was performed over all compounds towards 3s7s and 5jm5, as functional tumor proteins. The docking interaction parameters, introduced strongly some synthesizes to be anti‐tumor agents. Electrostatic potential contour from total electron density
Influence of certain experimental factors and methods of data processing on the correctness of the resultant kinetics is considered on the basis of dynamic model of differential scanning calorimeter, DSC. Firstly, essential effect of sample temperature deviation from linearity or from constant outer temperature due to heat accumulation in the sample on reaction proceeding is discussed. Disregard of this effect may and will be one of the reasons of obtaining the inadequate kinetics. The method for calculation of sample temperature deviation (reconstructing sample temperature) is proposed. Secondly, influence of a DSC curve distortion due to thermal inertia of the cell on the results of kinetic analysis is considered. The method for correction of this distortion (data deconvolution) is presented which can be safely used for processing of data of kinetic experiments. Special attention is paid to the importance of data deconvolution when the kinetic experiment is carried out under isoperibolic conditions. Finally, the combined effect of temperature deviation and inertia-induced distortions is considered. It should be emphasized that the matters considered are especially important when energetic materials are tested due to big heat release and rate of heat generation. At first, all the matters are discussed on the basis of simulated data. This allows elimination of various uncertainties of real experiment and influence of unknown kinetic model and gives vivid illustration of the subject. Then, the effects are demonstrated on the basis of real experimental data. Both the model-free and model-based kinetics evaluation methods were used. The simple method is proposed which allows vivid cross-verification of both these types of kinetics.
The study of the influence of carbon content from 10 to 17 at. % on undercooling ability and crystallization processes of melts of the Fe-Cr-C system at 15 at.% Cr was conducted. The studies were carried out by methods of differential thermal analysis and metallography. DTA of alloys performed in the heating regime at a rate of 20 °C/min to the selected melt temperature and subsequent cooling at a rate of 100 °C/min after 20 min exposure at a given temperature. Based on the heating thermograms, a phase diagram of the Fe-Cr-C system in the studied concentration range was constructed. The phase diagram obtained in the high temperatures area corresponds to a eutectic type diagram. The eutectic between γ-Fe(Cr) and (Fe,Cr)23C6 carbide is observed at 14 at.% C and a temperature of 1230 °C. A study of the crystallization of Fe85-xCr15Cx (x=10-17) melts under cooling from 1600 °C at a cooling rate of 100 °C/min showed that in the equilibrium eutectic area near 14 at.% C there is a minimum on the concentration dependence of undercooling ability. In addition, the crystallization ofFe85-xCr15Cx (x=10-17) melts proceeds according to the nonequilibrium mechanism and starts with the formation of iron-based solid solution, γ-Fe (Cr), in the first stage. It has been established that the main influence on the solidification processes is exerted by a change in the interaction between chromium and carbon atoms in the melt. An increase in the chemical interaction between Cr and C atoms leads to an increase in the crystallization ability of γ-Fe; therefore, at a eutectic concentration in the region of maximum viscosity, the minimum undercooling ability values under the conditions of which primary γ-Fe crystals formed are observed. Thus, the results obtained about the conditions and sequence of phase formation in Fe85-xCr15Cx (x=10-17) melts shown that the observed nonequilibrium crystallization is primarily determined by a change in the chemical interaction in the liquid state, namely, an increase in the interaction between Cr and C atoms at the eutectic concentration.
Aluminum micropowders are the precursors in many industries, such as powder metallurgy, self;propagating high;tem;perature synthesis of new materials, hydrogen energy, pyrotechnics and rocket fuels. Improvement of characteristics of aluminum pow;ders contributes to their quality. The known methods of aluminum powders activation by addition of rare;earth elements, vanadiumcompounds, silicon, boron and other elements into the aluminum mixtures composition lead to contamination of aluminum with impu;rities. b?;radiation exposure of micropowders with the energy less than 8 MeV does not lead to induced radioactivity and activates alu;minum micropowders at the same time.
Актуальность. Микропорошки алюминия являются сырьем для многих отраслей промышленности: порошковой металлургии, самораспространяющегося высокотемпературного синтеза новых материалов, водородной энергетики, пиротехники и ракетных топлив. Улучшение характеристик порошков алюминия способствует повышению их качества. Известные способы активирования порошков алюминия путем введения в состав алюминия добавок редкоземельных элементов, соединений ванадия, кремния, бора и других элементов приводит к загрязнению алюминия примесями. Облучение микропорошков β-частицами с энергией менее 8 МэВ не приводит к наведенной радиоактивности и в то же время активирует микропорошки алюминия. Цель: получение и объяснение экспериментальных данных по изменению параметров активности микропорошков алюминия после их облучения в зависимости от дозы β-облучения. Объекты: микропорошки алюминия АСД-6, АСД-6М, АСД-8, АСД-10, полученные распылением расплава алюминия. Методы: дифференциальный термический анализ, рентгенофазовый анализ, методика облучения микропорошков алюминия β-излучением, методика расчета параметров активности порошков алюминия. Результаты. Получены количественные показатели реакционной способности микропорошков алюминия АСД-6, АСД-6M, АСД-8 и АСД-10 до и после облучения β-излучением ускорителя ЭЛУ-4 с энергией 4 МэВ, т. е. энергией существенно ниже порога фотоядерных реакций, приводящих к наведенной активности. Дозы облучения образцов порошков составляли 1, 2, 4 Мрад. После β-облучения температура начала окисления снизилась максимально на 205 °С; максимальная скорость окисления возросла на 0,19 мг/мин (106 %); степень окисленности микропорошка АСД-6М повысилась на 18,9 %, а микропорошка АСД-10 минимально понизилась на 12,3 %; удельный тепловой эффект окисления после всех доз β-облучения увеличился максимально для АСД-10 на 188,6 кДж/моль. Запасание энергии микропорошками после β-облучения связано с формированием двойного электрического слоя в частицах алюминия.
New thiazole derivatives were synthesized and fully characterized, then coordinated with PtCl4 salt. Also, the newly synthesized Pt(IV) complexes were investigated analytically (elemental and thermogravimetric analyses), spectrally (infrared, UV–visible, mass, 1H NMR, 13C NMR, X‐ray diffraction) as well as theoretically (kinetics, modeling and docking). The data extracted led to the establishment of the best chemical and structural forms. Octahedral geometry was the only formula proposed for all complexes, which is favorable for d6 systems. The molecular ion peaks from mass spectral analysis coincide with all analytical data, confirming the molecular formula proposed. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) allowed discrimination of features between crystalline particles and other amorphous morphology. By applying Gaussian09 as well as HyperChem 8.2 programs, the best structural forms were obtained, as well as computed significant parameters. Computed parameters such as softness, hardness, surface area and reactivity led us towards application in two opposing pathways: tumor inhibition and oxidation activation. The catalytic oxidation for CO was conducted over PtO2, which was yielded from calcination of the most reactive complex. The success of catalytic role for synthesized PtO2 was due to its particulate size and surface morphology, which were estimated from XRD patterns and SEM images, respectively. The antitumor activity was tested versus HCT‐116 and HepG‐2 cell lines. Mild toxicity was recorded for two of the derivatives and their corresponding complexes. This degree of toxicity is more favorable in most cases, due to exclusion of serious side effects, which is coherently attached with known antitumor drugs. The synthesis process for thiazole derivatives 5a–e.
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