Challenges and opportunities for energy recovery from municipal solid waste in the Russian Federation

Energy recovery from municipal solid waste (MSW) is currently a key factor in waste management in Russia, as can be seen from the corresponding changes in the state regulatory framework. The paper presents a comparative assessment of different waste flow characteristics; it focuses on pre-treatment options and the method of subsequent thermal treatment. It reflects the basic method of untreated MSW incineration and other advanced technologies which have different levels of waste preparation. Step-by-step research has been carried out in a large Russian city in order to determine different technological approaches to recovering energy from MSW. The study included: 1) field studies of the composition and characterization of MSW; 2) laboratory studies of MSW thermal properties, i.e. moisture, ash content and calorific value; 3) several options for waste treatment schemes with equipment of different technical specifications; 4) analysis of material flow, energy flow and key substance flow according to these considered schemes. The research revealed that for all seasons a significant proportion of MSW (almost 40%) is represented by fines (below 50 mm). On average, the energy potential of MSW (the total content of waste paper, polymers, textiles, wood, multilayer packaging, leather, rubber, footwear) amounts to about 40%. It was found that MSW calorific value depends on fraction size, since screening (over 50 mm) is characterized by high moisture and low content of valuable components, compared to MSW greater than 50 mm in size. Pre-processing and treatment of MSW allows solid recovered fuel (SRF) to be obtained with a calorific value similar to brown coal. The energy balance of the process allows the conclusion that 33.8% of initial MSW energy potential is concentrated in residues from the sorting process, since it has a relatively low calorific value of 4.8 MJ/kg, but a high mass fraction of 47.9%. In the process of MSW treatment and solid fuel production, most of the chlorine and mercury (80% and 55% respectively) is removed by the rest of the sorting process. The data obtained in the study can be used in selecting the optimal option for energy recovery from MSW. © 2019 WIT PressACKNOWLEDGEMENT The work was supported by Act 211 Government of the Russian Federation, contract № 02.A 03.21.0006

The effects of liquid-phase oxidation of multiwall carbon nanotubes on their surface characteristics

The development of new sorbents based on nanostructured carbon materials recently became a perspective field of research. Main topic of current study is to investigate the effect of different regimes of multiwall carbon nanotubes (MWCNT) surface modification process on their structural characteristics. MWCNT samples were treated with nitric acid at high temperature. Structural properties were studied using low temperature nitrogen adsorption and acid-base back titration methods. The study showed that diluted nitric acid does not affect MWCNT structure. Concentrated nitric acid treatment leads to formation of 2.8 carboxylic groups per 1 nm{2} of the sample surface

The pH Level Influence on Hydroxyapatite Phase Composition Synthesized with Hydrothermal Method

This paper reports the pH level influence on hydroxyapatite phase composition synthesized with hydrothermal method in Ca(OH)2-H3PO4, Ca(NO3)2-(NH4)2HPO4-NH[4]OH, Ca(OH)[2]-NH[4]H[2]PO[4].The obtained samples were studied with X-Ray diffraction, Fourier Transform Infrared (FTIR) and Raman spectroscopy. The one phase Ca[5]H[2]O[13]P[3] high crystallinity hydroxyapatite was synthesized with hydrothermal method at pH equal to 11. The crystallinity degree was calculated from the X-Ray diffraction pattern and became 0.96. The increasing pH level from 7 to 11 provides obtaining one phase hydroxyapatite at pH level 11 instead the two phase Ca[9.04](PO[4])6(OH)[1.68], CaHPO[4] at pH level 9 and CaPO[3](OH), Ca(OH)[2] at pH level 7

The pH Level Influence on Hydroxyapatite Phase Composition Synthesized with Hydrothermal Method

This paper reports the pH level influence on hydroxyapatite phase composition synthesized with hydrothermal method in Ca(OH)2-H3PO4, Ca(NO3)2-(NH4)2HPO4-NH[4]OH, Ca(OH)[2]-NH[4]H[2]PO[4].The obtained samples were studied with X-Ray diffraction, Fourier Transform Infrared (FTIR) and Raman spectroscopy. The one phase Ca[5]H[2]O[13]P[3] high crystallinity hydroxyapatite was synthesized with hydrothermal method at pH equal to 11. The crystallinity degree was calculated from the X-Ray diffraction pattern and became 0.96. The increasing pH level from 7 to 11 provides obtaining one phase hydroxyapatite at pH level 11 instead the two phase Ca[9.04](PO[4])6(OH)[1.68], CaHPO[4] at pH level 9 and CaPO[3](OH), Ca(OH)[2] at pH level 7

Influence of postcoid syndrome on the quality of training of students of the medical-preventive faculty

The article presents the influence of postcovid syndrome on the quality of education of students of the medical-prophylactic faculty.В статье представлено влияние постковидного синдрома на качество обучения студентов лечебно-профилактического факультета

Analysis of bow-tie antenna properties for brain microwave radiometry

В работе приведены результаты исследования одной из конструкций вибраторных антенн-аппликаторов, применяемых для контактных неинвазивных измерений собственного электромагнитного излучения головного мозга. Исследования проведены с помощью численного моделирования (гибридным методом конечных элементов и методом моментов), реализованного в программном пакете FEKO Suite 7.0. В этой среде была построена модель тканей головы человека и выполнена оптимизация антенны. В качестве критериев оптимизации выбраны: минимальный коэффициент отражения и максимальная напряженность электрического поля на глубине 50 мм. Рассчитаны частотные зависимости коэффициента отражения и мощности, сосредоточенной в различных тканях. Определено распределение плотности мощности в структуре. По полученным результатам сделан вывод, что антенна, оптимизированная по максимальной напряженности поля, обеспечивает прием большей доли мощности с внутренних слоев мозга.In this work, the results of a study on bow-tie antenna for contact noninvasive measurements of self-radiation of a human brain are presented. The investigation was carried out using numerical modeling (hybrid finite elements method and method of moments) by employing FEKO Suite 7.0. In this software the design of human head model was analyzed and the antenna optimization was conducted. The optimization goals are to minimize the reflection coefficient and maximize the electric field at a depth of 50 mm. The frequency dependencies of reflection coefficient and power collected from different tissues were calculated. The power density distribution was defined in the structure. It was found that the antenna, which was optimized in order to maximize electric field strength, provides better reception of energy from deep brain layers

The investigation of the pervasion of an electromagnetic wave through human skin with sucface discontinuity in the form of pore

В данной работе рассмотрены особенности прохождения электромагнитной волны с частотой 2,4 ГГц через кожу человека с неоднородностями в виде пор. Оценена величина напряженности электрического поля под неоднородностью для различных материалов заполнения поры кожи. Определено распределение напряженности электрического поля в сечении модели при прохождении электромагнитной энергии через пору. По полученным результатам сделан вывод, что участки кожи, содержащие неоднородности в виде пор, лучше пропускают электромагнитное излучение на частоте 2,4 ГГц чем участки кожи без неоднородностей.In this paper, the features of the pervasion of electromagnetic waves on a 2.4 GHz frequency in the model of human skin with discontinuity in the form of pore is considered. The electric field distribution under the pore for different materials filling the pore was found. The distribution of the electric field in the cross section of the model with electromagnetic energy passing through the pore was obtained. By the results obtained it was concluded that skin with pores better transmits electromagnetic radiation at a frequency of 2.4 GHz than the skin without any discontinuities

Effect of the plasma-forming gas consumption on processes of plasma spray coating and metal powder production

The influence of the plasma-forming gas consumption on the plasma flow velocity and its turbulence intensity is analyzed. Full-scale experiment conducted to confirm the results of the mathematical experiment. Comparative analysis of the results of practical and theoretical experiments showed satisfactory convergence. As a result of the study, developers and consumers of equipment are offered recommendations for improving the technology. © Published under licence by IOP Publishing Ltd

Microwave treatment and pH influence on hydroxyapatite morphology and structure

This paper reports the influence of microwave treatment duration and pH conditions of initial precursors on the morphological and crystalline dispersity of the hydroxyapatite (HAp) synthesized by hydrothermal method.The obtained HAp samples were studied by scanning electron microscopy, X-Ray diffraction method and low nitrogen adsorption method. We have obtained nanostructured crystalline hydroxyapatite with 95% crystallinity, porous structure and average particles size in interval 17...46 nm consolidated in aggregates with size distribution of 0.5...25 [mu]m. The pH growth from 8 to 13 results in double increase of HAp specific area(from 69 up to 133 m{2}/g), meanwhile microwave irradiation brings to particles aggregation: HAp treated during 0... 10...30 min have specific surface are 112...67...41 m{2}/g, respectively. As a result at pH=13 and without microwave irradiation treatment we synthesized HAp with maximum surface compared to the surface of natural HAp that makes obtained HApto be promising material in biotechnological applications