Papers by Keyword: Atmosphere

Abstract: Since its first appearance in 1995, metal-organic framework materials (MOFs) have become a research hotspot in the field of environmental treatment due to its advantages of large specific surface area, high porosity and adjustable pore size, especially in the treatment of dye wastewater and heavy metal wastewater. With the deepening of research, as a kind of crystalline material with porous structure, MOFs have a wide application prospect in the field of air purification materials due to their strong adsorption function. This paper summarizes the types and synthesis methods of MOFs, and reviews the application research progress of MOFs in gas separation, gas storage and particulate matter purification. At present, MOFs still have some problems, such as poor stability, low recycling efficiency, high cost and weak functionalization, etc. In the end of this paper, some research suggestions are put forward to solve these problems.

Abstract: It was determined that the current method of the Bakalsk mining department siderite ore preparation for blast-furnace smelting does not allow production of concentrate meeting the state-of-the-art metallurgy requirements. The most perspective method is reducing firing when a metallized product with higher iron content is obtained. It was demonstrated that implementation of this method requires the use of a three-zone shaft furnace having the oxidizing roasting zone, the reduction zone and the reduced product cooling zone. Experiments were carried out on the siderite ore reducing firing on laboratory units. The possibility in principle was demonstrated for production of the reduced product with iron content of 60 – 65% from the siderite ore. After the magnetic dressing the concentrate with iron content of 65 – 75% was obtained. It was determined that firing and reduction in hydrogen atmosphere result in the fired product reduction degree of 97 %. The possibility to produce a product suitable for blast-furnace conversion with the reduction degree of about 60% with the use of natural gas air conversion gas was demonstrated. The obtained results were used in the process development for the siderite ore reducing firing in a three-zone shaft furnace.

Abstract: A manufacturing process was developed using an electric through-type furnace for capillary tubes used for single-use injection syringes. The process flow diagram consisting of a number of sequential steps and tube heat treatment conditions in protective atmosphere of pure hydrogen providing also for the tube purging with inert gas were considered. The electric furnace installed capacity and heating element dimensions were found as a result of the thermotechnical calculations. Industry research was carried out with a view to optimize the annealing process of capillary tubes in the electric furnace. A choice of material for the muffle fabrication was justified. Temperature fields inside the muffles were evaluated. The optimal flow of protective gas and the maximum allowable flow of purging gas in the form of nitrogen and argon were determined. Mechanical properties were studied for tubes (stocks), welded at the medical goods fabrication plant in Tumen and fabricated at the Pervouralsky Novotrubny Plant. Test data were obtained for optimal rates of tube movement in the furnace, allowing production of capillary tubes, acceptable for medical needle fabrication after annealing. It was demonstrated that capillary tube heat treatment, ensuring the required condition of both outside and inside surfaces, as well as required mechanical properties, is possible with the use of nitrogen as protective (instead of hydrogen) and purging gases. At that probability of better tube surface condition significantly grows.

Abstract: By adopting dynamic induction furnace corrosion test, the corrosion mechanism of lightweight Al₂O₃-MgO castable with different environmental oxygen partial pressure was investigated through macro- and micro-analysis, XRD and thermodynamic simulation. The atmospheric condition was set to P(O₂) = 0.21 atm or P(Ar) = 1.0 atm. The attained results showed that a reduced slag corrosion but intensified slag penetration happened at low environmental oxygen partial pressure condition. With P(O₂) = 0.21atm, Mn and Fe in slag were present in the form of divalent and/or trivalent cations and were incorporated into spinel to form MnFe₂O₄ solutions and MgAl₂O₄ solutions during corrosion process. Since Fe, Mn ions are largely consumed, liquid with high viscosity formed and the continuing infiltration was suppressed. Under P(Ar) =1.0 atm, corrosion on castable aggregates was significantly weakened, and the reaction products under this condition are mainly MgAl₂O₄ and CA₆.

Abstract: The article presents the results of applying environmental mechanics in research of absorber for capturing emissions’ hydrocarbons vapors exhausting from the gas station into the atmosphere air. Often residential human habitants are located within the boundary of the sanitary protection zone (SPZ) of these gas filling stations. The analysis measurement’s and stratification’ modeling results these gas emissions’ in the atmosphere showed that benzene and xylene vapor’s concentration in the atmosphere exceeds the existing sanitary-hygienic norms for these ingredients often. There presented the research results of the proposed aspiration schemes was equipped absorbing device for the capture of gas vapor’ emissions at the gas station in this article. It was obtained the regressions of capture effectiveness for the proposed device by mathematical processing. The research results were implemented for design of pilot industrial set up that was installed and successful tested in one of the gas filling station in Russia. It was showed the reliability of the proposed device for practical commercial use.

Abstract: In the influence of the atmosphere,the soil of the subgrade would frequently in continuous humidification and dehumidifying situation, and it will result in large variation of the engineering properties of the subgrade. So, it is important to study the water migration in subgrade under the influence of the climate. In this paper, based on moisture and heat coupling thermal, non isothermal equation of unsaturated soil are introduced, the subgrade evaporation model are established. The theoretical analysis and numerical calculation of the subgrade moisture changes and its influence factors under the effect of the atmosphere are studied. The study results show that: solar intensity are the most important factors to the subgade moisture, the solar radiation makes the temperature of the pavement rising, the evaporation of the pavement would be speed up. In the wet and dry cycle process, as the rainfall intensity is small, it has little effect to the subgrade moisture, in the same rainfall duration conditions, although the evaporation duration is the same, the subgrade moisture still changes with the rainfall intensity, the larger the rainfall, the more changes of the subgrade moisture. Little intensity and long duration rainfall pattern affect the subgrade moisture more intensity than that of large intensity and short duration rainfall pattern.

Abstract: This paper analyses effects of boiling treatment of aluminum alloys (Al–(5-10)% Cu and Al–(5-10)% Si) in oxidizing atmosphere on their microstructure, hydrogen content and coefficient of linear thermal expansion (CLE). Boiling treatment was conducted in water solutions of KMnO₄ and KOH. Following an increase of boiling time from 15 to 75 hours hydrogen content in alloys first increases and then decreases which correlates with the dynamics of alloys’ microstructure and their coefficient of linear expansion. This study shows that atmosphere with high oxygen content induces acceleration of diffusion processes in aluminum alloys. If boiling time does not exceed 30 hours, hydrogen content in solid solution and etchability of grain boundaries of α-solid solution decrease and intermediate phases get partially dissolved. In our empirical study we demonstrated that boiling treatment of aluminum alloys in oxidizing atmosphere in the range of test temperatures 50-450°С leads to a reduction of the coefficient of linear expansion. The decrease of the coefficient of linear expansion is especially strong in the temperature range of 250-350°С. In particular, after boiling treatment of alloys Al–(5-10)% Cu in oxidizing athmosphere in the temperature range of 50–250°С their coefficient of linear expansion goes down by 10-12%. For alloys Al–(5-10)% Si boiling has a stronger effect on the coefficient of linear expansion – in the temperature range 250-350°С the CLE of these alloys decreases by 24-28%.

Abstract: Thermogravimetric analysis (TGA), coupled with Fourier transform infrared analysis (TG-FTIR) of sewage sludge was carried out to investigate the influence of moisture and oxygen on gas evolution during pyrolysis of sewage sludge. Wet sewage sludge with moisture of 86.47(wt. %) was collected from Shanghai, China. Wet sewage sludge and air dried sewage sludge were used in TG-FTIR analysis, while combustion (air flow) and pyrolysis (nitrogen flow) were separately introduced to achieve comparison. In condition of dry sewage sludge pyrolysis, there were two peaks representing release of separately moisture and volatile. Weight lost 85% in the temperature range of 25-600 °C while the main volatile matters were released before 600 °C. When air flow was introduced, a third peak of char combustion occurred. Wet sewage sludge made no much difference, except for the relatively outstanding peak of moisture release. Temperature regions for each stage were the same for wet and dry sewage sludge from TG curve. However, from the FTIR analysis, ammonia has two peaks between 50 and 450 °C in pyrolysis while ammonia has only one peak between 50 and 300°C.

Abstract: The main influence factors on thermal analysis of medium-density fiberboard (MDF) was analyzed by thermo-gravimetry (TG) and derivative thermo-gravimetry (DTG) , which are heating rate, atmosphere and sample . Results showed that heating rate affected the thermo-decomposition obviously, while the effect on the residual charcoal was small, The results can provide reference to extinguishment and fire investigation.

Abstract: The study used the bibiometric analysis to assess papers on emission inventory from 2001-2012, based on the SCIE and SSCI databases. The paper analyzed publication outputs, subject categories, major journals, authors’ outputs, geographic distribution of publications, international collaboration and author keywords. Our research identified a total of 5995 emission inventory-related publications during the period. Most of the papers related to emission inventory were published in journals linkd to the atmosphere. Streets, DG from Argonne National Laboratory contributed most in the research of emission inventory whose total papers, total citations, the average number of citations and H-index were all in the leading position. The USA, with the most independent and internationally collaborative papers, cooperated with China most. Global emission inventory research focused on life cycle assessment, greenhouse gases, models, remote sensing and so on, which may serve as a foundation for further research in emission inventory field.