Evaluation of kinetic parameters of coal ignition

A method is presented of evaluating the kinetic parameters for the ignition reaction of coal based on the Semenov's thermal ignition theory adopted to coal particle ignition. The evaluated apparent activation energy, E, for bituminous coal, anthracite and bituminous coal char are in the range 46–103 kJ mol^?1. A verification was made by comparing the measured induction periods for the coal particles with those calculated numerically. The oxidation rate is controlled by diffusion into pores.     

Adhesion of Triple-Negative Breast Cancer Cells under Fluorescent and Soft X-ray Contact Microscopy

Understanding cancer cell adhesion could help to diminish tumor progression and metastasis. Adhesion mechanisms are currently the main therapeutic target of TNBC-resistant cells. This work shows the distribution and size of adhesive complexes determined with a common fluorescence microscopy technique and soft X-ray contact microscopy (SXCM). The results presented here demonstrate the potential of applying SXCM for imaging cell protrusions with high resolution when the cells are still alive in a physiological buffer. The possibility to observe the internal components of cells at a pristine and hydrated state with nanometer resolution distinguishes SXCM from the other more commonly used techniques for cell imaging. Thus, SXCM can be a promising technique for investigating the adhesion and organization of the actin cytoskeleton in cancer cells.     

Reduction of convective heat transfer losses from flat surfaces

The study of reduction of convective heat transfer losses from flat surfaces by means of vertical perimenter wall has been presented. The optimum screening wall height has been theoretically calculated as: (H/D)_cr = 6.283/Ra^5/16. To determine the phenomenon of influence of plate screen on convective heat transfer, Nusselt-Rayleigh correlation has been given. The experimental data were in substantial agreement with the theoretical results.     

Serum Concentrations of TNF �� and Its Soluble Receptors in Patients with Adrenal Tumors Treated by Surgery

The peripheral blood levels of TNF α and its soluble receptors were studied in 39 patients with malignant and benign adrenal tumors treated by adrenalectomy. The concentrations of TNF α were significantly elevated in patients with malignant tumors of the adrenal cortex and in patients with Conn’s syndrome compared to control. In patients with non-functioning adenomas and pheochromocytomas, TNF α levels were similar to those detected in the control. In subjects with myelolipomas, the serum concentration of TNF α was lower compared to the control. After adrenalectomy, the levels of TNF α were decreased in patients with malignant tumors and in patients with Conn’s syndrome, nonfunctioniong adenomas and pheochromocytomas compared to the concentration before surgery. The serum concentrations of soluble receptors of TNF α did not differ among different patient groups and compared to the control. After adrenalectomy, the blood concentrations of TNF α R1 and TNF α R2 were decreased in patients with Conn’s syndrome. However, to confirm practicality of the evaluation of TNF α and its soluble receptors in differential diagnosis in patients with adrenal tumors, a larger study group is needed.     

Measurement of gas flow rate from helium standard leaks

Helium standard leaks are widely used to check and calibrate mass spectrometer leak detectors. Precisely known gas flows are required for measurement of quantities of standard leak rates. A fundamental task of the constructed and presented calibration apparatus is precise measurement of gas leak rate. Thus a primary standard for calibration helium standard leaks in the range from 10⁻¹⁰ to 10⁻⁵ Pa m³/s has been completed at the Laboratory of Vacuum Measurements in Tele & Radio Research Institute.     

Investigations on Romashkino asphaltic bitumen. 1. Use of ion-exchange and adsorption chromatography for the separation of maltenes

Use has been made of ion-exchange resins to remove acid and base fractions from maltenes originally separated from Romashkino asphaltic bitumen. The effect has been studied of the ion-exchange resin treatment on the group-type composition of maltenes using adsorption chromatography through alumina. Yields, elemental and densimetric analyses of sub-fractions obtained have been given. Data from the separation will aid in the characterization of the nonhydrocarbon materials generally described as resins.     

The influence of stereochemistry on the antioxidant properties of catechin epimers

The influence of stereochemistry on the radical scavenging activity of catechins was investigated by studying the effect of pH on the antioxidant properties of catechin epimers. The difference in the pH-dependent Trolox equivalent antioxidant capacity (TEAC) profiles was observed only in case of gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG), indicating the influence of steric structure on the TEAC antioxidant activity of these galloyl moiety-containing catechins. Based on comparison of the pH-dependent TEAC values to theoretically calculated parameters, including homolytic OH bond dissociation energy and ionization potential (IP) as well as theoretically predicted structures of the most stable monoanions of GCG and EGCG, it was concluded that due to steric hindrance in GCG molecule, the IP value of GCG monoanion increases reflecting lower radical scavenging capacity of GCG in comparison with EGCG. It results in the difference in the pH-dependent TEAC profiles of these two catechin epimers at pH above 3.5. This effect does not occur for other pairs of catechin epimers of this study.     

Protein profile and sensorial properties of rye breads

The protein profile of four types of traditional rye breads formed on rye flours with the extraction rate of 100, 95, 85 and 70% and baked at 260 °C for 40 min was investigated as a nutritional quality indicator. A fractionation process was applied to discriminate high-molecular- (HMW >3 kDa) and low-molecular weight compounds (LMW <3 kDa) present in extracts of rye bread and its crumb and crust. The content of soluble proteins, available lysine, carbohydrates and total phenolic compounds was analysed before and after ultrafiltration in both retentates (HMW >3 kDa) and filtrates (LMW <3 kDa). The dependence between sensory quality of rye breads and composition on soluble proteins, available lysine, carbohydrates and total phenolic compounds was provided. Baking caused a decrease in rye bread protein content. The content of available lysine was the lowest in crusts and it was dependent on the rye flour extraction rate taken for rye bread making. The SDS-PAGE analysis showed that the primary structure of the rye bread proteins was modified in the highest extent in the crust’s bread of all types. The analyses of both retentates and filtrates after ultrafiltration demonstrated that the most of carbohydrates and phenolic compounds were incorporated into the HMW fraction suggesting their conjugation with proteins due to the Maillard reaction. Compounds able to react with Folin Ciocalteu reagent were also detected in filtrates of crust’s extracts (MW ≤3 kDa) from all breads indicating their distribution between LMW and HMW fractions. About 22.5, 27, 11.2 and 46.8% of the phenol compounds forming crusts of breads based on the flours with extraction rates of 100, 95, 85 and 70% were recovered in the corresponding LMW fractions.The sensory analysis of the four types of rye breads indicated for a high correlation between overall quality of breads and their content of carbohydrates. The highest correlation was noted for a rye bread formed on flour with extraction rate of 95%. This finding suggested that the content of carbohydrates as a substrate for Maillard reaction has had an influence on palatability by consumers of rye bread formed on flour with the extraction rate of 95% which had also the highest overall quality.     

Dynamics of a rope modeled as a multi-body system with elastic joints

A discrete model of a rope with spiral springs in joints is considered, the aim being to include transverse elasticity of the rope. Elastic characteristic of the springs is derived on the basis of simple geometrical formulas and the classical curvature-bending moment relationship for beams. Lagrange’s equations of motion are presented and their complexity is discussed from the computational point of view. Numerical experiments are performed for a system with both scleronomic and rheonomic constraints. The influence of the elasticity on behaviour of the model is analyzed. Results validity is examined in terms of basic energy principles.     

Epoxy resin cured with diamine bearing azobenzene group

The epoxy resin: N,N-diglycidyl-4-glycidyloxyaniline (DGOA) is cured with the new diamine-chromophore: 2,4-diamino-4′-methylazobenzene (DMAB). The spectral characterization of infrared spectroscopy (FTIR), ¹H NMR spectroscopy and of elemental analysis (EA), confirm the chromophore structure. The curing kinetics of aminophenol epoxy resin/2,4-diamino-4′-methylazobenzene system is studied in isothermal experiments by means of differential scanning calorimetry (DSC). The structural changes occurring during the cure reaction are investigated by Fourier transform infrared spectroscopy (FTIR). Thermal stability characterized by the temperature of 5 and 10% weight loss and residue at 1000 °C of the cured product is studied by thermogravimetric analysis (TGA). Amorphous character of the cured material is determined using X-ray spectroscopy. The preliminary investigations of optical grating recording are carried out.