Spectral properties and observables in ultracold Fermi gases

We calculate non-perturbative self-consistent fermionic and bosonic spectral functions of ultra-cold Fermi gases with the spectral functional approach. This approach allows for a direct real-time computation of non-perturbative correlation functions, and in the present work we use spectral Dyson-Schwinger equations. We focus on the normal phase of the spin-balanced Fermi gas and provide numerical results for the full fermionic and bosonic spectral functions. The spectral functions are then used for the determination of the equation of state, the Tan contact and ejection rf spectra at unitarity. These results are compared to experimental data, the self-consistent T-matrix approach and lattice results. Our approach offers a wide range of applications, including the ab initio calculation of transport and spectral properties of the superfluid phase in the BCS-BEC crossover

Правовые проблемы трансформации отходов в продукцию (на примере фосфогипса)

The subject. One of the problems of contemporary states is waste and the search for opportunities for transformation into products. In this aspect, phosphogypsum, which is a waste product of mineral fertilizers, is interesting. It is subject to recycling in a small amount now.he purpose of the article is to identify legal possibilities for regulating relations related to industrial waste in terms of their secondary use.The main results, scope of application. Phosphogypsum can be used for the construction of highways, dams; the production of fertilizers and salts; the production of construction products using non-recycled phosphogypsum; agriculture; in the production of gypsum binders and products made from them; in the cement industry; as a filler in various industries. With the technological possibility of recycling such waste as phosphogypsum, there is no legal possibility of their use. The absence of the necessary legal regulation of relations in the field of waste disposal, clear legally fixed criteria for classifying waste as secondary material resources and the possibility of their use, may entail certain negative consequences for economic entities.Conclusions. The process of waste transformation into products from a legal point of view should consist of the following stages: waste disposal (both with and without pretreatment); the process of waste transformation into products directly (with a license for waste of hazard classes I – IV, compliance with licensing requirements, conclusion of the state environmental expertise on processing and disposal technologies, equipment used in this process, etc.). The following stage is legally correct and documented recognition of waste that is secondary material resources. The last stage is exclusion of said waste that is secondary material resources from approved waste generation standards and limits on their placement, as well as reflection of their movement in the journal of waste generation and movement.Одной из проблем современных государств являются отходы производства, в связи с чем приобретет важность поиск возможностей по их переработке и превращению в продукцию. В этом аспекте интересен фосфогипс, являющийся отходом производства минеральных удобрений. На сегодняшний день он в незначительном объеме подлежит вторичной переработке. Целью статьи является выявление правовых возможностей для регулирования отношений, связанных с отходами производства в части их вторичного использования. В статье сделаны выводы о том, что процесс трансформации отходов в продукцию с юридической точки зрения должен состоять из следующих стадий: утилизация отходов (как с предварительной обработкой, так и без нее); непосредственно процесс превращения отходов в продукцию (с наличием лицензии для отходов I–IV классов опасности, соблюдением лицензионных требований, положительным заключением государственной экологической экспертизы на технологии обработки и утилизации, технику, применяемую в данном процессе, и т. п.); юридически корректное и документально оформленное признание отходов, являющихся вторичными материальными ресурсами; исключение указанных отходов, являющихся вторичными материальными ресурсами, из утверждаемых или утвержденных нормативов образования отходов и лимитов на их размещение, а также отражение их движения в журнале учета образования и движения отходов

Deposition of arsenic from nitric acid leaching solutions of gold—arsenic sulphide concentrates

At present, the processing of refractory gold–arsenic sulphide concentrates is becoming more relevant due to the depletion of rich crude ore reserves. In the process of the nitric acid leaching of arsenic sulphide minerals, solutions are formed containing 20–30 g/L of arsenic (III). Since market demand for arsenic compounds is limited, such solutions are traditionally converted into poorly soluble compounds. This paper describes the investigation of precipitating arsenic sulphide from nitric acid leaching solutions of refractory sulphide raw materials of nonferrous metals containing iron (III) ions using sodium hydrosulphide with a molar ratio of NaHS/As = 2.4–2.6, which is typical for pure model solutions without oxidants. The work studied the effect of temperature, the pH of the solution and the consumption of NaHS and seed crystal on this process. The highest degree of precipitation of arsenic (III) sulphide (95–99%) from nitric acid leaching solutions containing iron (III) ions without seed occurs with a pH from 1.8 to 2.0 and a NaHS/As molar ratio of 2.8. The introduction of seed crystal significantly improves the precipitation of arsenic (III) sulphide. An increase in seed crystal consumption from 0 to 34 g/L in solution promotes an increase in the degree of transition of arsenic to sediment from 36.2 to 98.1% at pH = 1. According to SEM/EDS and XRF sediment data, from the results of experiments on the effect of As2S3 seed crystal consumption, acidity and molar ratio of NaHS/As on the precipitation of arsenic (III) sulphide and the Fetotal/Fe2+ ratio in the final solution, it can be concluded that the addition of a seed accelerates the crystallisation of arsenic (III) sulphide by increasing the number of crystallisation centres; as a result, the deposition rate of As2S3 becomes higher. Since the oxidation rate of sulphide ions to elemental sulphur by iron (III) ions does not change significantly, the molar ratio of NaHS/As can be reduced to 2.25 to obtain a precipitate having a lower amount of elemental sulphur and a high arsenic content similar to that precipitated from pure model solutions. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work was financially supported by the Russian Science Foundation Project No. 20-79-00321. The SEM–EDS analyses were funded by State Assignment, Grant No. 0836-2020-0020

Pressure oxidation of arsenic (Iii) ions in the h3aso3-fe2+-cu2+-h2so4 system

The processing of low-grade polymetallic materials, such as copper–zinc, copper–lead– zinc, and poor arsenic-containing copper concentrates using hydrometallurgical methods is becom-ing increasingly important due to the depletion of rich and easily extracted mineral resources, as well as due to the need to reduce harmful emissions from metallurgy, especially given the high content of arsenic in ores. Ferric arsenates obtained through hydrothermal precipitation are the least soluble and most stable form of arsenic, which is essential for its disposal. This paper describes the investigation of the oxidation kinetics of As (III) ions to As (V) which is required for efficient puri-fication of the resulting solutions and precipitation of low-solubility ferric arsenates. The effect of temperature (160–200 °C), the initial concentration of Fe (II) (3.6–89.5 mmol/dm3), Cu (II) (6.3–62.9 of mmol/dm3) and the oxygen pressure (0.2–0.5 MPa) on the oxidation efficiency of As (III) to As (V) was studied. As (III) oxidation in H3AsO-Fe2+-Cu2+-H2SO4 and H3AsO-Fe2+-H2SO4 systems was controlled by a chemical reaction with the apparent activation energy (Ea (≈84.3–86.3 kJ/mol)). The increase in the concentration of Fe (II) ions and addition of an external catalyst (Cu (II) ions) both have a positive effect on the process. When Cu (II) ions are introduced into the solution, their catalytic effect is confirmed by a decrease in the partial orders, Fe (II) ions concentration from 0.43 to 0.20, and the oxygen pressure from 0.95 to 0.69. The revealed catalytic effect is associated with a positive effect of Cu (II) ions on the oxidation of Fe (II) to Fe (III) ions, which further participate in As (III) oxidation. The semi-empirical equations describing the reaction rate under the studied conditions are written. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work was financially supported by the Russian Science Foundation Project No. 20‐ 79‐00321

Computation of the ejector characteristics for the SOFC power unit: cold gases

The article describes two methods of the ejector characteristics computation: numerical and analytical. The characteristicsof the ejector for anode gas recirculation in the SOFC power unit were obtained by both methods. The results are instrumental for experimental characteristics determination with inlet flows at the ambient temperature.В работе представлено два метода расчёта характеристики эжектора: численный и аналитический. Характеристики эжектора для рециркуляции анодных газов в составе энергоустановки на твёрдооксидных топливных элементах были рассчитаны по обоим методикам. Полученные результаты позволяют грамотно спланировать эксперименты по снятию характеристики такого аппарата при комнатной температуре газов на входе

Punishing childhoods: contradictions in children’s rights and global governance

The article considers efforts to eradicate corporal punishment as an aspect of the global governance of childhood and raises problems relevant to global governance more broadly. The article analyses contradictions in children’s rights advocacy between its universal human rights norms and implicit relativist development model. Children’s rights research is influenced by social constructivist theories, which highlight the history of childhood and childhood norms. Earlier social constructivist studies identified the concept of childhood underpinning the Convention on the Rights of the Child (CRC) as a Western construction based on Western historical experiences, which excluded the experiences of childhood in developing countries. More recent social constructivist approaches emphasise how childhood norms are constructed and therefore can be reconstructed. The article outlines problems with attempts to globalise childhood norms without globalising material development. The article discusses the softening of discipline norms in Western societies historically. It indicates problems with children’s rights advocacy seeking to eradicate the corporal punishment of children globally without globalising the material conditions, which underpin the post-industrial ideal of childhood embodied in the CRC

Wastewater Disinfection Alternatives: Chlorine, Ozone, Peracetic Acid and UV Light

Disinfection tests were carried out at pilot scale to compare the disinfection efficiency of ozone, sodium hypochlorite (NaOCl), peracetic acid (PAA), and UV irradiation. Total coliforms, fecal coliforms, and Escherichia coli were monitored as reference microorganisms. Total heterotrophic bacteria (THB) were also enumerated by cytometry. At similar doses, NaOCl was more effective than PAA, and its action was less affected by contact time. The results obtained by ozonation were comparable for total coliforms, fecal coliforms, and E. coli. On the contrary, some differences among the three indicators were observed for NaOCl, PAA, and UV. Differences increased with increasing values of the disinfectant concentration times contact time (Ct) and were probably the result of different initial counts, as total coliforms include fecal coliforms, which include E. coli. The UV irradiation lead to complete E. coli removals, even at low doses (10 to 20 mJ/cm2). Total heterotrophic bacteria appeared to be too wide a group to be a good disinfection indicator; no correlation was found among THB inactivation, dose, and contact time