Theory and practice of unit creation for technogenic material compacting

No Abstrac

Separation of the Groups of Humic Substances upon Recurrent Treatment with Solvents

The recurrent (up to 20 times) reprecipitation of an alkaline extract from the Al horizon of dark gray forest soil by acids at pH 1.5 does not provide a complete separation of the acid-soluble fraction from the acid-insoluble residue of humic substances. A satisfactory separation of the residue into hymatomelanic and humic acids can be achieved by several treatments with dioxane, provided that the residue is subjected to reprecipitation before every extraction procedure

Effect of the Soil Dehydration Temperature on the Vapor-Phase Sorption of p-xylene

The effect of two methods for the preparation of soil samples for sorption experiments-hard (dehydration at 105°C) and mild (drying over P2O5 at 20°C in vacuum) drying-on the values of the vaporphase sorption of p-xylene was studied depending on the content of organic matter in the soil. It was shown with dark gray forest and chernozemic soils as examples that the hard drying of soil samples taken from the upper layer of the humus profile with a high content (>4%) of organic carbon decreased their sorption capacity in the range of 0-5% by 7-81%. Therefore, the method is unsuitable for these soils. It was also found that the mild method of soil preparation had obvious analytical advantages. © 2010 Pleiades Publishing, Ltd

Effect of organic matter on the sorption activity of heavy loamy soils for volatile organic compounds under low moisture conditions

© 2014, Pleiades Publishing, Ltd. The diverse effect of the organic matter content on the sorption of vapors of aromatic and aliphatic hydrocarbons in soils under low moisture (<10.5%) has been revealed in sorption experiments using profile samples from two virgin heavy loamy dark gray forest soils characterized by relatively stable contents of finely dispersed mineral components. The decrease of the hydrocarbon sorption with increasing the content of organic matter under dry conditions (in the moisture range from 0 to 5–6%) indicates its lower sorption activity than that of the clay components and the blocking of the sorption sites on soil minerals by organic matter. At moisture contents above 5–6%, the effect of the soil composition on the sorption activity changes radically: it increases with increasing the content of organic matter. This is due to the inversion of the ratio between the activities of the soil components because of the hydrophilization of the surface of the mineral soil component. As a result, the sorption of water on the minerals reduces the mineral sorption activity to hydrocarbons to a lower level than the activity of organic matter. The maximum manifestation of the revealed blocking effect has been observed for the low-humus soils and this effect decreased with the accumulation of soil organic matter

Methodological aspects of fractionation of humus substances

The separation of humus as a nonadditive entity comprising an indefinite multitude of high-molecular substances differing in molecular weight and chemical heterogeneity into homogeneous fractions is discussed, with the developed procedure of fractional dissolution as an example. The problem of humus fractionation is theoretically solvable, but kinetic limitations make it unfeasible under laboratory conditions because of long duration. Epistemological aspects of the problem are discussed. Copyright © 2004 by MAIK "Nauka/Interperiodica" (Russia)

Ni-Al mixed oxides as catalysts in the reactions of conversion of the higher alkanes

© SGEM2018. In this study, investigation of the composition, structure and catalytic activity of the catalyst support based on Ni-Al mixed oxides was carried out. The possibility of controlling structural and acid-base properties of the layered double hydroxides (LDH) by varying the ratio of M2+/M3+ metal cations determines its use as catalyst support. Besides varying of anions in the interlayer space allows to regulate catalytic system activity in the reaction medium. The Ni-Al LDH support was prepared by coprecipitation method followed by conversion to Ni-Al mixed oxide in the reaction medium. According to the X-ray diffraction analysis, it was shown that the Ni-Al-based mixed oxide obtained with a specific surface area of 158 m2/g contains nickel oxide with a reduced lattice parameter related with the replacement of part of Ni2+ cations with Al3+, phase of mixed oxides of variable composition and amorphous phase. The replacement of Ni2+ by Al3+ in nickel positions is 16%. The crystallite size of the obtained oxide phases is 4 nm. The catalytic activity of Ni-Al mixed oxide was determined in the reactions of the conversion of higher alkanes of the C11-C22 composition, taken in equal proportions, at a temperature of 500°C and a feed to catalyst ratio of 30. According to the chromatographic analysis, alkanes and isoalkanes of composition C7-C14 were formed as catalytic products. Unsaturated compounds in the reaction products were revealed by IR spectroscopy method; the iodine value was 0.172

Application of low pressure capacitively coupled rf hydrogen plasma for low temperature reduction of iron clusters in structure of fe-pillared materials

© Published under licence by IOP Publishing Ltd.The unique properties of pillared materials determine their use in catalysis, purification and separation. The paper studies the reduction of composite catalysts, Fe-pillared materials. The authors compare their reduction in low temperature capacitively coupled RF hydrogen discharge of low pressure to their conventional direct hydrogen reduction in a tubular muffle furnace. X-ray diffraction analysis was used to characterize the iron-bearing phases. The results show that the reduction of iron hydro/oxide clusters associated with an aluminosilicate matrix to metallic iron is very challenging due to the degree of the pore space availability for hydrogen

Aquathermolysis of heavy oil using nano oxides of metals

© 2017 Elsevier B.V.The effect of suspended nanoparticles of magnetite and hematite on thermal decomposition of heavy oil at a temperature of 360 °C in a vapor medium at different system pressures is revealed. The preferential destruction reactions of macromolecular components of oil, which lead to the reduction of oil viscosity, are established. The effect of zinc and aluminum oxides as additives initiating cracking of hydrocarbon bonds is studied. The changes in structure of the component of the converted products, as compared to the original crude oil, are obtained. Conducting the process in the presence of additives at a pressure of 11 MPa led to the reduction of the aromaticity of the final products, increase in the yield of hydrocarbon oils and the formation of gaseous products. It is observed that the amount of asphalt-resinous substances is reduced as the result of their conversion in the presence of additives. Rheological curves of conversion products are obtained, based on them the peculiarities of viscosity-temperature characteristics change can be shown

Антимикробная фотодинамическая терапия в голосовой реабилитации пациентов после ларингэктомии

The article is devoted to the problem of voice rehabilitation of patients after laryngectomy. Modern possibilities of repairing laryngeal vocal function, methods for extending the lifetime of voice prostheses are considered. The author’s method of prevention of infection of vocal prostheses using the antimicrobial photodynamic therapy (PDT) with chlorin-type photosensitizer Radagel is presented. Performing antimicrobial PDT of vocal prostheses increased the average operating time to 11.9 months compared to the control group (6.8 months), where a monthly dose of 150 mg of fluconazole was used for prevention. The method developed by the authors makes it possible to significantly extend the lifetime of vocal prostheses, is devoid of adverse events, is well tolerated by patients.Статья посвящена проблеме голосовой реабилитации пациентов после ларингэктомии. Рассмотрены современные возможности восстановления голосовой функции после ларингэктомии, способы увеличения срока эксплуатации голосовых протезов, представлен авторский метод профилактики инфекции голосовых протезов с помощью антимикробной фотодинамической терапии (ФДТ) с фотосенсибилизатором хлоринового ряда. Проведение антимикробной ФДТ голосовых протезов позволило увеличить средний срок эксплуатации до 11,9 мес по сравнению с контрольной группой (6,8 мес), где для профилактики использовали ежемесячный прием 150 мг флуконазола. Антимикробная ФДТ позволяет существенно продлить срок эксплуатации голосовых протезов, не имеет побочных явлений, хорошо переносится больными

A new approach to use of oral mucosa in reconstructive urethral surgery: micrografts

Introduction. Treatment of patients with complex urethral strictures is an actual problem of reconstructive urology. After multi-staged urethral surgery with multiple revisions the new reconstruction is limited by paucity of plastic material (for grafts and flaps). In-thing, new materials for urethral reconstruction (various auto, allo and xenografts) are still being developed in reconstructive urethral surgery.Purpose of the study. To study the possibility of using oral mucosa micrografts to form the urethral plate in the multi-stage surgery for patients with extended urethral strictures.Materials and methods. In the experimental study, male Wistar rats (22 individuals) weighing 300 – 400 g underwent a full-thickness skin wound after intramuscular sedation. We used the wound chamber (12 mm diameter) to exclude the wound contraction. The oral mucosa graft was harvested (6 mm in diameter). After pre-fabrication, the graft was minced to fragments &lt; 1 mm2. Micrografts with fibrin-thrombin glue were applied to the wound. By day 45, the epithelial plate was excised for histological examination. In the clinical study, 4 patients with recurrent penile urethral strictures were treated with staged urethroplasty with urethral plate formation using oral mucosa micrografts. The average length of the stricture was 7.5 ± 1.2 cm (with extremely narrow and obliteration sites). The urethral plate was formed as the first stage. The preparation of the graft bed and oral mucosa grafts harvesting was carried out according to the standard procedure. Micrografts preparation and implantation was carried out as in experimental part of this study. After 6 months, neourethra tubularization was performed. The patients were evaluated every 3 months after the final stage of urethroplasty (uroflowmetry, ultrasound, X-ray, PROM-USS). The median follow-up was 9 months (3 – 18 months).Results. On day 15, in the experimental study, in 16 of 22 (72.7%) rats, the wound chambers had focal growth of the oral mucosa epithelium. On day 45, the wounds healed completely healed with oral mucosa. The final area of the plate was 78 ± 12 mm2. In the clinical study, 6 months after the first stage, all patients (n = 4) had a urethral plate covered with an oral mucosa epithelium without scar formation and sufficient for neurethra tubularization. All patients underwent urethral tubularization. After catheter removal, all men urinated. After 9 months (median follow-up, n = 3), the Qmax was 22.7 ± 4.2 ml/s, the post-void residual urine was 34.8 ± 2.2 ml, the total PROM-USS score was 7.4 ± 1.2, urethral lumen is preserved. All patients showed high satisfaction with the treatment.Conclusion. The oral mucosa micrografts showed good take in heterotopic transplantation (72.7%) with the formation of an epithelial layer on the wound surface. The final mucosal plate area 3 times exceeded the initial micrografts area. This initial clinical experience of using oral mucosa micrografts shows the new possibility of this technology in reconstructive urethral surgery, especially in patients with complex urethral strictures