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المؤلفون: N. E. Fedorova, M. V. Egorova, A. S. Rodionov, M. S. Grechina
المصدر: Ovoŝi Rossii, Vol 0, Iss 3, Pp 57-62 (2020)
مصطلحات موضوعية: 0106 biological sciences, microwave mineralization, chemistry.chemical_element, Growing season, atomic absorption analysis, Residual, 01 natural sciences, Mineralization (biology), law.invention, copper-containing pesticides, law, 010405 organic chemistry, fungi, food and beverages, Agriculture, Pesticide, Pulp and paper industry, Copper, 0104 chemical sciences, chemistry, plant products, Dry ice, Environmental science, shredding with dry ice, Atomic absorption spectroscopy, 010606 plant biology & botany
الوصف: Relevance and methods. Methodological approaches to assessing the residual amounts of copper-containing pesticides in plant products against the background of natural copper content are presented. The conditions for obtaining reliable results when conducting a hygienic assessment of the content of residual amounts of the active substance are determined. The developed scheme for determining the residual amounts of copper-containing pesticides includes the homogenization of the analyzed material by shredding with dry ice and microwave mineralization of samples with subsequent flameless atomic absorption determination of copper.Results. Data on the levels of natural copper content in samples of potatoes, onions, cucumbers, tomatoes and grapes of various varieties and growing areas are presented. The possibility of applying the developed approaches to study the dynamics of accumulation of active substances during the growing season is shown.
URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a8d8cc96b6af5f8a2c549a7c92662d0d
https://doi.org/10.18619/2072-9146-2020-3-57-62 -
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المؤلفون: Julius Pollaehne, Steven J. Lehotay, Manol Roussev
المصدر: Journal of Agricultural and Food Chemistry. 67:9203-9209
مصطلحات موضوعية: 0106 biological sciences, Nitrogen, Sample (material), Sample processing, Food Contamination, 01 natural sciences, Dry Ice, Process engineering, Pesticide residue, business.industry, 010401 analytical chemistry, Pesticide Residues, General Chemistry, Liquid nitrogen, Pesticide, Animal Feed, 0104 chemical sciences, Freeze Drying, Fruit, Food processing, Dry ice, Environmental science, Comminution, General Agricultural and Biological Sciences, business, 010606 plant biology & botany
الوصف: With the monitoring of hundreds of pesticides in food and feed, the comminution step is equally crucial as any other to achieve valid results. However, sample processing is often underestimated in its importance and practical difficulty to produce consistent test portions for analysis. The scientific literature is rife with descriptions of microextraction methods, but ironically, sample comminution is often ignored or dismissed as being prosaic, despite it being the foundation upon which the viability of such techniques relies. Cryogenic sample processing using dry ice (-78 °C) is generally accepted in practice, but studies have not shown it to yield representative test portions of
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المؤلفون: Pau Loke Show, Muhammad Mubashir, Mohamad Azmi Bustam, Sidra Saqib, Abul Hassan Ali Quddusi, Muhammad Babar, Sami Ullah, Ahmad Mukhtar
المصدر: Process Safety and Environmental Protection. 147:878-887
مصطلحات موضوعية: Packed bed, 021110 strategic, defence & security studies, Work (thermodynamics), Environmental Engineering, Materials science, business.industry, General Chemical Engineering, Nuclear engineering, 0211 other engineering and technologies, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Dynamic simulation, Switching time, CO2 content, Natural gas, Dry ice, Environmental Chemistry, Safety, Risk, Reliability and Quality, business, Saturation (chemistry), 0105 earth and related environmental sciences
الوصف: Desublimation-based Carbon dioxide (CO2) removal from the natural gas (NG) in a cryogenic packed bed becomes challenging due to the dry ice formation inside the packed bed. Therefore, the cryogenic packed bed has been used for NG purification only in batch processes. However, to fulfill the energy requirements, it is crucial to develop a continuous process for NG purification, which is difficult for a single cryogenic packed bed. In the current research, a novel cryogenic packed bed system is proposed for continuous capture of desublimation based CO2 capture from natural gas. The process feasibility of the switching concept was proved through dynamic simulation and experimental study on CO2 separation from multi-component NG. It was observed that increasing CO2 content decreases the switching and saturation time of the cryogenic packed bed. The total energy required per packed bed per cycle in the switching system is 133.35. The saturation time for pure CO2 feed, NG sample-1, and NG sample-2 were 300, 500, and 600 s, respectively. An excellent agreement was observed between the results obtained from the experimental results and that obtained through dynamic simulation. A switching time of 200 s was found for a CO2 recovery of more than 98 %. This research work offers scientific data and theoretical support for the industrial application of switched cryogenic packed bed setup in CO2 capture from natural gas in the future. Moreover, in the current research work, scale-up study, and automatic control system for the switched packed bed are recommended for the future.
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المؤلفون: Andrea Fischer, Lea Hartl, Gabriele Schwaizer, Lucia Felbauer
المصدر: The Cryosphere, Vol 14, Pp 4063-4081 (2020)
مصطلحات موضوعية: lcsh:GE1-350, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, 0211 other engineering and technologies, Glacier, 02 engineering and technology, Albedo, Atmospheric sciences, 01 natural sciences, Debris, lcsh:Geology, Deglaciation, Dry ice, Environmental science, Satellite, Spatial variability, lcsh:Environmental sciences, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Ablation zone
الوصف: As Alpine glaciers become snow-free in summer, more dark, bare ice is exposed, decreasing local albedo and increasing surface melting. To include this feedback mechanism in models of future deglaciation, it is important to understand the processes governing broadband and spectral albedo at a local scale. However, few in situ reflectance data have been measured in the ablation zones of mountain glaciers. As a contribution to this knowledge gap, we present spectral reflectance data (hemispherical–conical–reflectance factor) from 325 to 1075 nm collected along several profile lines in the ablation zone of Jamtalferner, Austria. Measurements were timed to closely coincide with a Sentinel-2 and Landsat 8 overpass and are compared to the respective ground reflectance (bottom-of-atmosphere) products. The brightest spectra have a maximum reflectance of up to 0.7 and consist of clean, dry ice. In contrast, reflectance does not exceed 0.2 for dark spectra where liquid water and/or fine-grained debris are present. Spectra can roughly be grouped into dry ice, wet ice, and dirt or rocks, although gradations between these groups occur. Neither satellite captures the full range of in situ reflectance values. The difference between ground and satellite data is not uniform across satellite bands, between Landsat and Sentinel, and to some extent between ice surface types (underestimation of reflectance for bright surfaces, overestimation for dark surfaces). We highlight the need for further, systematic measurements of in situ spectral reflectance properties, their variability in time and space, and in-depth analysis of time-synchronous satellite data.
وصف الملف: application/pdf
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المؤلفون: Ch. Tampaxis, Th.A. Steriotis, Fotios K. Katsaros, Andreas A. Sapalidis, K.L. Stefanopoulos, Tristan G. A. Youngs, Daniel T. Bowron
المصدر: Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques. 14:S221-S224
مصطلحات موضوعية: Materials science, Triple point, Scattering, chemistry.chemical_element, 02 engineering and technology, Microporous material, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, chemistry.chemical_compound, chemistry, Chemical engineering, Phase (matter), Carbon dioxide, Dry ice, 0210 nano-technology, Mesoporous material, Carbon
الوصف: The phase behavior and the properties of carbon dioxide confined in an ordered mesoporous carbon (CMK-3) during freezing near the bulk triple point have been investigated by in situ total neutron scattering. The CO2 condensed in the mesopores of CMK-3 is found to be in a much densified state comparable with the bulk dry ice. So far, CO2 densification effects have been observed only in microporous carbon materials.
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المؤلفون: Fotios K. Katsaros, Theodore Steriotis, K.L. Stefanopoulos, Daniel T. Bowron, Tristan G. A. Youngs, Christos Tampaxis, Andreas Sapalidis
المصدر: Carbon. 167:296-306
مصطلحات موضوعية: Materials science, Scattering, Triple point, chemistry.chemical_element, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, chemistry, Chemical physics, Phase (matter), Dry ice, General Materials Science, Neutron, 0210 nano-technology, Supercooling, Mesoporous material, Carbon
الوصف: The molecular structure and phase behavior of carbon dioxide confined in an ordered mesoporous carbon (CMK-3) are investigated by total neutron scattering with in situ adsorption and cooling/heating cycles. The neutron signal from CO2 sorbed in the micropores of CMK-3 shows clearly liquid-like properties. Close to the bulk CO2 triple point (T3), the mesopore-confined CO2 is found in a liquid yet strongly densified state with a density similar to that of solid dry ice. Upon cooling the CO2 loaded carbon sample below T3, it was observed that depletion of the confined phase occurs and CO2 molecules escape from the pores to solidify externally. It was concluded that depletion occurs only in “secondary” pores having larger sizes (>50 A) than the well-defined uniform mesopores (47 A) of CMK-3. These pores exist due to imperfect ordering of the hexagonal network of the carbon rods. Surprisingly, this phenomenon does not happen in the main mesopores (47 A), implying thus that 50 A is a critical size for depletion below T3. This in turn suggests that in larger pores a pore triple point cannot be attained. The depletion process is reversible with a temperature hysteresis; when heating the sample CO2 molecules re-fill the pores.
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المؤلفون: Mhd Ikhwanuddin, Koh Ivan Chong Chu, Hairul Hafiz Mahsol, Ali Amatul-Samahah, Shahreza Md Sheriff, Che Ismail Che-Zulkifli, Mohamad N. Azra
المصدر: Egyptian Journal of Aquatic Research, Vol 46, Iss 3, Pp 245-250 (2020)
مصطلحات موضوعية: Artificial insemination, 010501 environmental sciences, Aquatic Science, Oceanography, 01 natural sciences, lcsh:Aquaculture. Fisheries. Angling, Cryopreservation, Total protein, Grouper, Bradford protein assay, lcsh:Environmental sciences, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Water Science and Technology, lcsh:SH1-691, lcsh:GE1-350, chemistry.chemical_classification, Chromatography, biology, Chemistry, 04 agricultural and veterinary sciences, Plasma, Epinephelus, Liquid nitrogen, biology.organism_classification, Amino acid, 040102 fisheries, Dry ice, Amino acids, 0401 agriculture, forestry, and fisheries
الوصف: The present study aims to investigate the effects of exposure of the seminal plasma and spermatozoa of the giant grouper Epinephelus lanceolatus to dry ice (−79 °C) during transport on their quality. In all, 15 amino acid compounds were determined. The quantification of total proteins were measured using the Bradford method, and amino acid concentration were measured using the HPLC method. The cryopreserved seminal plasma was transferred from a liquid nitrogen tank to a styrofoam box filled with dry ice. Total protein and amino acids were measured after 24, 48, and 72 h. For comparative purposes, total protein and fifteen compound of amino acid were also measured. Both parameters were also measured after the cryopreserved seminal plasma were immersed in liquid nitrogen after 24 and 48 h exposed to dry ice. The results showed that the exposure of seminal plasma to dry ice for 24, 48 and 72 h during transportation or immersion back into the liquid nitrogen after 24 and 48 h does not change the total protein levels either in seminal plasma or spermatozoa. However, the level of each amino acid compound in the seminal plasma had significantly decreased.
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المؤلفون: Faisal Md Basir, Mohammad Reza Safaei, Mohamad Nur Hidayat Mat, Mohd Shareduwan Mohd Kasihmuddin, Norzelawati Asmuin, Taufiq Khairi Ahmad Khairuddin, Marjan Godarzi
المصدر: Journal of Thermal Analysis and Calorimetry. 144:2159-2173
مصطلحات موضوعية: Materials science, Dry-ice blasting, Nozzle, 02 engineering and technology, Mechanics, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Sound power, 01 natural sciences, 010406 physical chemistry, 0104 chemical sciences, Momentum, symbols.namesake, Mach number, Turbulence kinetic energy, symbols, Particle velocity, Physical and Theoretical Chemistry, 0210 nano-technology, Intensity (heat transfer)
الوصف: One of the important parameters in developing dry ice blasting nozzle is the high-speed dry ice pellets. However, many studies focus primarily only on its performance without considering the noise emission that comes from an operating nozzle. In this method, the central composite optimization tool has been used. The two-way mass momentum and energy exchange are successfully modeled using the two-way mass momentum model. As an attempt to theoretically verify the model accuracy, a comparison is conducted on the density, pressure, temperature, as well as Mach number ratios corresponding to various ratios of nozzle area. In return, the smallest value of the convergent angle results in the highest velocity of 516.75 m s−1, as well as the highest level of the acoustic power level of 144.36 dB. Besides, one of the vital influencing factors on the emitted acoustic power level is the turbulence intensity, which can achieve a maximum of 1% intensity for an angle of 20° at the throat section. Besides, the same negative sensitivity of around − 0.99% is provided by the velocity and acoustic power level, which is highly responsive toward the convergent angle variation. Furthermore, the optimum nozzle convergent angle for the minimization of the acoustic power level and maximization of the velocity is 7.03°. The novelty of this research lies in the findings on the effective convergent angle of the dry ice blasting nozzle that accelerates the particle flow and minimizes the noise emission from the operating nozzle.
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المصدر: Environmental Science and Pollution Research International
مصطلحات موضوعية: Health, Toxicology and Mutagenesis, Organic and inorganic matter, 010501 environmental sciences, Waste Disposal, Fluid, 01 natural sciences, Phase Transition, law.invention, chemistry.chemical_compound, Ammonia, law, Dry Ice, Freezing, Transition Temperature, Environmental Chemistry, Sublimation, Chemical, Crystallization, Turbidity, Infrared radiation, 0105 earth and related environmental sciences, Biological Oxygen Demand Analysis, Sewage, Chemistry, Chemical oxygen demand, Phase transformation processes, General Medicine, Models, Theoretical, Pollution, Waste-activated sludge, Activated sludge, Chemical engineering, Carbon dioxide, Bench scale, Dry ice, Sublimation (phase transition), Research Article
الوصف: The freezing process consists of dissipating heat from the product until the final temperature is lower than the temperature of crystallisation of that product. Freezing can be used for numerous applications, including for disruption of waste-activated sludge (WAS). The aim of this study was to calculate the estimated amount of heat conveyed between the solidified carbon dioxide and the WAS, in the following ratios: 0.25:1; 0.5:1; 0.75:1 and 1:1. In heat of phase transformations, dry ice sublimation, water solidification, the amount of heat transferred by other substances and heat transferred from the sludge (dry sludge) were taken into account during the process of WAS freezing. Heat changes on the surface of WAS were registered using a thermovision camera. The effectiveness of WAS disintegration was confirmed by several biochemical parameters such as soluble chemical oxygen demand (increase over 14 times), degree of disintegration (48%), proteins (increase over 5 times), carbohydrates (increase almost 7 times), RNA (increase by 2.23 mg L−1), ammonia nitrogen (increase over 23 times), phosphates (increase almost 27 times) and turbidity (increased over 7 times). It was found that dry ice pretreatment of WAS can be an intriguing alternative for the conventional methods used. Electronic supplementary material The online version of this article (10.1007/s11356-019-05889-2) contains supplementary material, which is available to authorized users.
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المؤلفون: Paolo Mocellin, Chiara Vianello, Giuseppe Maschio
المصدر: Process Safety and Environmental Protection. 126:167-181
مصطلحات موضوعية: Work (thermodynamics), Environmental Engineering, Operability, CCS Safety, Vessel depressurization, CO2,Source Model, Dry-ice, General Chemical Engineering, CCS Safety, 0211 other engineering and technologies, Vessel depressurization, 02 engineering and technology, 010501 environmental sciences, Hazard (computer architecture), 01 natural sciences, Mass flow rate, Environmental Chemistry, Safety, Risk, Reliability and Quality, 0105 earth and related environmental sciences, Dry-ice, 021110 strategic, defence & security studies, Mechanics, Pipeline (software), Pipeline transport, Heat transfer, Environmental science, CO2, Source Model, Body orifice
الوصف: In the framework of emerging Global Warming strategies, CO2 sequestration pipelines require attentive hazard studies to ensure a safe operability, but current risk assessment procedures applied to CO2 pipeline failures lack reliable and comprehensive source models. This work suggests a resolutive and robust multiphase discharge model suited for matching all expected CO2 discharge mechanisms. The application to real scale CO2 pipelines shows an essential incidence of the pipeline geometry (length and internal diameter) as well as of the orifice size on the release features. Wider thermal dynamics and enlarged solid contents are expected in short pipelines subjected to large ruptures. The resulting expansion transformations are characterized by increasing degrees of reversibility. Results show that expected solid content may amount up to 45% on a mass basis under usual carbon sequestration operative conditions. The latter, being linked to the initial CO2 aggregation state, play a key role in determining the whole discharge dynamics especially because of the effects of phase change mechanisms. A peculiar mass flow rate discharge profile is observed depending on the occurrence of liquid-vapor and solid-vapor mixtures. Specific set of geometric and operative conditions allow for the applicability of the isothermal bulk hypothesis and negligible wall effect in heat transfer mechanisms. Main governing parameters are the ratio between the pipeline length and internal diameter L/D and that between the orifice and the internal pipeline diameter d/D. Essential in driving the QRA procedure is the occurrence of the solid phase in rapid depressurizations that is expected only for pipeline shorter than 1500 m subjected to d/D > 0.30. Independently on the operative temperature, only pipelines carried at pressures above 55 barg lead to CO2 solid-vapor mixtures. Under these conditions, the solid CO2 cannot be neglected thus requiring a QRA modelling procedure considering additional scenarios involving sublimative dynamics of a dry ice bank.
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