Oxygen-poor Environment Research Articles

Glucose-assisted preparation of vacancy-rich ZnO sheets for photocatalytic activity enhancement

Vacancy-rich ZnO sheets with (1 0 0) facet were synthesized by the glucose-assisted calcination method. By introducing glucose to control the atmosphere, oriented growth of ZnO with oxygen vacancy was realized. Experimental results showed that the glucose-assisted calcination provided oxygen-poor environment for the formation of oxygen vacancy and promoted the transformation of ZnO from rods to sheets. ZnO sheets exhibited a high photocatalytic activity and regeneration ability. After 60 min of irradiation, methyl orange was completely decolorized and the degradation rate was still at 96 % after four-cycle experiments. The synergistic effect of oxygen vacancy and non-polar (1 0 0) facet improved the photocatalytic property of ZnO.

Thermodynamic characteristics and mechanism of low-rank coal oxidation in oxygen-poor environment

Aiming at the restricted oxygen environment of coal mine, this paper focus on the whole process from physical adsorption to chemical reaction between coal and oxygen, and quantum chemical calculations investigate the potentiating or inhibiting effects of different active groups on the amount of oxygen adsorbed and thermally released from the main coal structure, and experimentally investigate the effect of oxygen concentration (OC) on the transformation relationship between active functional groups and active sites. The results showed the coal side-chain structure has an effect on the heat release characteristics of the aromatic ring in the process of oxygen adsorption, and the heat of adsorption of the aromatic ring with alkyl and aldehyde side-chains reaches 422.706 kJ/mol. The relationship between carbon oxide release and temperature at different OC all conformed to the exponential function model, and the apparent activation energy was positively correlated with the OC. The increase of OC narrows the gap between the production and consumption rates of active sites, which is helpful for the further understanding of the coal spontaneous combustion (CSC).

Study on the oxidized gas production characteristics and spontaneous combustion tendency of pre-oxidized water-soaked coal in lean-oxygen environments.

The oxidation characteristics and spontaneous combustion (SC) tendency of raw long-flame coal (RC), water-soaked 200-day coal (S200), pre-oxidized water-soaked coal at 200°C (O200S200), and pre-oxidized soaked coal at 300°C (O300S200) in an oxygen-poor environment were investigated using a programmed warming system. The results show that pre-oxidation water-soaked treatment (PWT) promotes the coal-oxygen complex reaction and increases the rate of coal oxygen consumption (OCR) and the rate of carbon and oxygen compound production. The rate of CO and CO2 production of the water-soaked (WS) coal increased by 0.329mol·(cm3·s)-1 and 0.922mol·(cm3·s)-1, respectively, compared with that of the original coal sample. PWT reduces the activation energy of coal in the low-temperature oxidation stage (the maximum difference can be up to 110.99kJ/mol) and enhances the oxidizing and heat-releasing capacity. There was a synergistic effect between the pre-oxidation (PO) and WS treatment, and the lowest comprehensive determination index of the SC propensity of coal in O200S200 samples was 831.92 which was 4.72 lower than that of RC samples, presenting a more SC tendency. Low oxygen concentration has an inhibitory effect on the oxidation characteristic parameters of coal, and the apparent activation energy of the low-temperature oxidation stage of pre-oxidized water-soaked coal (PWC) increased to 206.418kJ/mol at 3% oxygen concentration. The lower the oxygen concentration of the anoxic environment, the lower the risk of SC of the coal samples. The results of the study can provide theoretical guidance for the identification and prevention of SC disasters in coal seams with shallow burial and close spacing.

Structural evolutions under surface oxidation of AgPd Alloy: From Orientation, composition and strain effects to catalytic application

The surface oxidation of AgPd alloys can significantly impact their catalytic activity, however, the detailed understanding of such dynamic mechanism and the prediction of catalytic activity is still lacking. Herein, a comprehensive investigation combining ab initio molecular dynamics simulations with experimental observations is performed. The surface oxidation of AgPd alloys is highly dependent on oxygen concentration, where AgOx forms in oxygen-poor environment and PdOx forms in oxygen-rich environment, and shows highly reliance on the orientation, composition and strain state. The oxidation level of Ag, Pd and AgPd alloys follows the trend of (111) < (100) < (110) under 1.0 ML of O coverage. Both Pd single-atom and Ag matrix atoms in PdAg single-atom alloys are susceptible to oxidation under 0.5 ML of O coverage, with the increase of Pd atom number, only AgOx forms. Tensile strain promotes the oxidation of Ag(111) surface by facilitating the inward diffusion of O atoms, while compressive strain promotes the oxidation of Pd(111) and AgPd(111) surfaces by facilitating the outward migration of Ag/Pd atoms. The oxidized AgPd(111) surface with tensile strain under 0.5 ML of O coverage exhibits the optimum electrocatalytic activity toward formate oxidation reaction.

Sedimentary Environment and Organic Accumulation of the Ordovician–Silurian Black Shale in Weiyuan, Sichuan Basin, China

The sedimentary environment and organic matter enrichment relationship of the Upper Ordovician Wufeng Formation black shale, Guanyinqiao mudstone, and Lower Silurian Longmaxi Formation black shale in the Sichuan Basin of Weiyuan are analyzed using geochemical methods such as organic carbon, sulfur, major elements, and trace elements. The experimental results illustrate that the upper section of the Wufeng Formation and the lower section of the Longmaxi Formation are organic matter enrichment layers. The presence of P indicates a high productivity level in the Sichuan Basin from the Late Ordovician to the Early Silurian. In addition, indicators such as V/Cr, Ni/Co, and S/C suggest that the Wufeng Formation was deposited under anoxic reductive conditions, that the ice age Guanyinqiao segment was in an oxygen-rich to oxygen-poor environment, and that the Longmaxi Formation was in a sulfidic environment. Mo/TOC indicates that the Wufeng Formation shale was controlled by a restricted basin and that the Guanyinqiao segment and the Longmaxi Formation were in a medium-to-weak retention environment. The weak correlation of TOC with P/Al and Al indicates that the level of primary productivity and terrigenous detritus had a minor effect on the organic matter enrichment of the Wufeng and Longmaxi Formation black shale. Conversely, the positive correlation of TOC with V/Cr and Ni/Co illustrates that the anoxic reductive sedimentary environment is the main factor affecting the organic matter enrichment of the Wufeng and Longmaxi Formation black shale. Based on these studies, the development model of organic-rich shales of the Ordovician–Silurian in Weiyuan, Sichuan Basin is proposed. This paper may provide a reference for shale gas exploration in the Wufeng–Longmaxi Formation and a sedimentary response to the major geological events of Ordovician–Silurian.

Geochemical Characteristics of Elements and Main Controlling Factors of Organic Matter Enrichment in Shale from Wufeng Formation to Submember Long-11 in Southern Sichuan

A total of 70 shale samples from seven core holes, namely, N203, N208, N209, N210, N211, N215 and N217, in Changning area, south Sichuan, were analyzed for major and trace elements. Based on an analysis of longitudinal variation characteristics of major and trace elements, the REDOX conditions, paleoproductivity, relative sea level height and terrigenous detrital injection amount of gas-bearing shale in Wufeng Formation–Submember Long-11 in the Changning area were studied. And, the main controlling factors of organic matter enrichment in Wufeng Formation–Submember Long-11 were discussed. The results show the following: (1) Trace elements Mo, U, Ba and Ni are relatively enriched in the shale of Wufeng Formation–Submember Long-11 in the Changning area, while the Co element is deficient. The flat distribution pattern of rare earth in Wufeng Formation–Submember Long-11 shows that the shale deposits are weakly influenced by terrigenous materials. The amount of terrigenous injection in Wufeng Formation is higher than that in Submember Long-11, and the amount of terrigenous injection increased gradually from the lower part of Bed Long-111 to the lower part of Bed Long-114. (2) The REDOX environment discrimination indexes such as U/Th, Ni/Co, V/Sc and δU show that the water REDOX conditions of Wufeng Formation–Submember Long-11 in the Changning area have changed many times during the shale sedimentary period, and the overall REDOX conditions are dominated by an anaerobic environment. The REDOX indexes at the boundary between Long-111 and Wufeng Formation are relatively small and in the oxidizing environment range. The REDOX index from Bed Long-111 to Bed Long-114 decreases gradually, and the anaerobic environment of Bed Long-111 and Bed Long-112 gradually changes to the oxygen-poor environment of Bed Long-113; and, the REDOX index of Bed Long-114 is the lowest, which is generally oxygen rich. (3) Organic matter enrichment in Wufeng Formation Submember Long11 in the Changning area is mainly controlled by REDOX conditions. Low terrigenous injection and a relatively high sea level have positive effects on organic matter enrichment, but there is no obvious relationship between the paleoproductivity and organic matter enrichment.

Microneedle-assisted transdermal delivery of perfluorotripropylamine-based oxygenated emulsion gel loaded with 5-aminolevulinic acid for enhanced photodynamic therapy of cutaneous squamous cell carcinoma

Topical photodynamic therapy (TPDT) is a clinical treatment for cutaneous squamous cell carcinoma (CSCC). However, the therapeutic efficacy of TPDT for CSCC is significantly weakened by hypoxia, which is caused by the oxygen-poor environment of the skin and CSCC and by the high oxygen consumption of TPDT itself. To overcome these problems, we developed a topically applied perfluorotripropylamine-based oxygenated emulsion gel loaded with the photosensitizer 5-ALA (5-ALA-PBOEG) by a simple ultrasound-assisted emulsion method. With the aid of the microneedle roller, 5-ALA-PBOEG dramatically increased the accumulation of 5-ALA in the epidermis and the dermis, as well as throughout the dermis; a total of 67.6% ± 9.97% of the applied dose penetrated into and through the dermis, which is 19.1±3.2-fold that of the 5-ALA-PBOEG without microneedle treatment group, and 16.9±0.3-fold that of the aminolevulinic acid hydrochloride topical powder treatment group (p<0.001). Meanwhile, PBOEG enhanced the singlet oxygen yield of 5-ALA-induced protoporphyrin IX. The results of in vivo antitumor activity in human epidermoid carcinoma (A431) bearing mice showed that by increasing the oxygen content in tumor tissues, the developed 5-ALA-PBOEG plus microneedle treatment and laser irradiation showed better tumor growth inhibition than the respective control formulations. In addition, the results of safety studies, including the multiple-dose skin irritation study, allergy tests, and skin H&E staining, demonstrated the safety of 5-ALA-PBOEG plus microneedle treatment. In conclusion, the 5-ALA-PBOEG plus microneedle treatment shows great potential in the fight against CSCC and other skin cancers.

Increasing Surface Functionalities of FeCl3-Modified Reed Waste Biochar for Enhanced Nitrate Adsorption Property

Ferric chloride (FeCl3) modified reed straw-based biochar was synthesized to remove nitrate from aqueous solutions and achieve waste recycling. The adsorption of nitrate onto Fe-RBC-600 adsorbents could be described by the pseudo-second-order kinetic model and fitted to Langmuir adsorption, and the maximum adsorption capacity predicted using the Langmuir model was 272.024 mg g−1. The adsorbent characterization indicated that a high temperature of 600 °C and an oxygen-poor environment could develop a hydrophobic surface and O-containing functional groups on the biochar, which provided more binding sites for Fe3+/Fe2+ attachment and increased the surface functionality of Fe-RBC-600 with iron oxide formation. The increasing surface functionality successfully enhanced the nitrate adsorption property. The mechanism of nitrate adsorption was mainly attributed to the physical adsorption onto the positive surface and sequential chemical reduction by Fe2+, and the electrostatic adsorption by protonated amine groups.

The Combustion of Forest Humus Blended with Low-Rank Coal: Effects of Oxygen Ratio and Blending Ratio

In this study, the combustion characteristics of pine needles, pine needle humus, and the co-combustion of these two types of biomass with coal were compared. In addition, the optimization of the combustion performance of coal/humus was assisted through the following studies: (i) the combustion performance of coal/pine needle humus was studied under four different oxygen concentrations (N2, 10%O2/90%N2, 20%O2/80%N2, and 40%O2/60%N2); (ii) the synergistic effect between the humus and coal during combustion was also investigated by adjusting the blending ratio and oxygen content; (iii) the mechanisms of the optimized combustion processes were expounded by kinetics and thermodynamics discussion. The results demonstrated that the combustion characteristics of the coal/humus blends were found to be higher than those of the coal/pine needle blends. The coupling interactions of the oxygen content and blending ratio contributed to the significant synergistic effect between the two fuels, and the synergistic effect showed a nonlinear variation with an increased oxygen concentration. The synergistic effect in a rich oxygen environment (O240%/N260%) is 5.1 times greater than that in the synthetic air (O220%/N280%) and 13.8 times greater than that in the oxygen-poor environment (O210%/N290%). Hence, the blending ratio could be adjusted to maintain the intensity of the synergistic effect in an oxygen-rich atmosphere.

Marine microbial corrosion inhibitation of an in situ formed oxide coating on Ti56Zr44 alloy

The microbiologically influenced corrosion causes serious harm to the titanium alloys used for marine engineering. It is of great significance to explore the methods to prevent the microbial corrosion of titanium alloy. In this work, an in situ formed ZrTiO4 coating was prepared on Ti56Zr44 (at. %) alloy by thermal oxidation treatment at 450 °C. The biofilm formation on Ti56Zr44 alloy with and without oxide coating was comparatively investigated by immersion experiments in 2216E culture medium containing Pseudomonas aeruginosa bacteria. The microbial corrosion behavior of Ti56Zr44 alloy was evaluated by electrochemical methods. The results show that Ti56Zr44 alloy displays pitting corrosion when immersing for 10 days. The maximum pitting depth is up to 3.7 μm after 30 days of immersion. The pitting corrosion is attributed to that oxygen poor environment under biofilm causes the transfer of bacteria extracellular electron to the passive film. TiO2 in passive film is reduced to Ti2O3, decreasing the stability of passive film. The synergistic action of the biofilm and chloride ions in medium solution leads to pitting corrosion. On the contrary, no pitting corrosion occurs on the coating surface in spite of the coverage with biofilm. The corrosion rate of the Ti56Zr44 alloy with oxide coating is decreased by nearly five times when immersing for 30 days. The improved chemical stability of the coated alloy result from that there are more covalent bonds and hydrogen bond receptors in lattice unit cell of ZrTiO4 than that of TiO2 or ZrO2. It is difficult for the stable chemical structure to accept extra electrons provided by bacteria and change its own valence. The good resistance of the oxide coating to microbiological corrosion increases the application potential of Ti56Zr44 alloy in marine engineering.

Water Shielding in the Terrestrial Planet-forming Zone: Implication for Inner Disk Organics

The chemical composition of the inner region of protoplanetary disks can trace the composition of planetary-building material. The exact elemental composition of the inner disk has not yet been measured and tensions between models and observations still exist. Recent advancements have shown UV shielding to be able to increase the emission of organics. Here, we expand on these models and investigate how UV shielding may impact chemical composition in the inner 5 au. In this work, we use the model from Bosman et al. and expand it with a larger chemical network. We focus on the chemical abundances in the upper disk atmosphere where the effects of water UV shielding are most prominent and molecular lines originate. We find rich carbon and nitrogen chemistry with enhanced abundances of C2H2, CH4, HCN, CH3CN, and NH3 by >3 orders of magnitude. This is caused by the self-shielding of H2O, which locks oxygen in water. This subsequently results in a suppression of oxygen-containing species like CO and CO2. The increase in C2H2 seen in the model with the inclusion of water UV shielding allows us to explain the observed C2H2 abundance without resorting to elevated C/O ratios as water UV shielding induced an effectively oxygen-poor environment in oxygen-rich gas. Thus, water UV shielding is important for reproducing the observed abundances of hydrocarbons and nitriles. From our model result, species like CH4, NH3, and NO are expected to be observable with the James Webb Space Telescope (JWST).

Geochemical characteristics and geologic significance of rare earth elements in oil shale of the Yan’an Formation in the Tanshan area, in the Liupanshan Basin, China

In the Tanshan area, in the Liupanshui Basin, abundant oil shale resources are associated with coals. We analyzed the cores, geochemistry of rare earth elements (REE), and trace element of oil shale with inductively coupled plasma mass spectrometry technology to define the paleo-sedimentary environment, material source, and geologic significance of oil shale in this area. The results of the summed compositions of REE, and the total REE contents (ΣREE), in the Yan’an Formation oil shale are slightly higher than the global average of the composition of the upper continental crustal and are lower than those of North American shales. The REE distribution pattern is characterized by right-inclined enrichment of light REEs (LREE) and relative loss of heavy REEs (HREE), which reflects the characteristics of crustal source deposition. There is a moderate degree of differentiation among LREE, whereas the differences among HREE are not obvious. The [Formula: see text] values indicate a weak negative anomaly, and the [Formula: see text] values indicate no anomaly, which are generally consistent with the distribution of REE in the upper crust. The characteristics of REE and trace elements indicate that the oil shale formed in an oxygen-poor reducing environment and that the paleoclimatic conditions were relatively warm and humid. The degree of differentiation of REE indicates that the sedimentation rate in the study area was low, which reflected the characteristics of relatively deep sedimentary water bodies and distant source areas. The results also proved that the source rock mainly consisted of calcareous mudstone, and a small amount of granite was also mixed in.

Quantitative identification and distribution of quartz genetic types based on QemScan: A case study of Silurian Longmaxi Formation in Weiyuan area, Sichuan Basin

As a key factor restricting the fracturing effect of shale reservoir, the origin and content of quartz components have always been the focus of academic and industrial circles. Due to the great influence of diagenesis process, the accuracy of trace element determination to identify the origin of quartz is not good, which can not meet the increasingly accurate research requirements. In this paper, mineral quantitative analysis technology (QemScan) is used to identify quartz components by two-dimensional quantitative scanning, and the content data of quartz components with different grain sizes are extracted. The results show that the size of quartz particles is obviously controlled by the difference of sedimentary water and sedimentary environment, that is, quartz particles less than 30 μm are mainly concentrated in Long112 and Long114 layers, which is the normal oxygen environment under the background of medium retention in deep water environment; quartz particles larger than 20 μm are mainly concentrated in Long111 and Long113 layers, which is the poor oxygen environment under the background of strong retention in deep water environment. In shallow water environment, the stronger hydrodynamic conditions make the strata rich in terrigenous clastic quartz particles with larger grain size, and oxygen poor environment is conducive to the enrichment of authigenic quartz with smaller grain size.

Interfacial exchange coupling-modulated magnetism in the insulating heterostructure of CoOx/yttrium iron garnet

The combination of yttrium iron garnet (Y3Fe2(FeO4)3, YIG) and ferromagnetic materials or antiferromagnetic materials has attracted much attention because of its potential in applications such as spin pumping. In this study, a high-temperature and oxygen-poor environment was used to deposit a CoOx top layer on YIG for the observation of magnetic modulation. The temperature- and saturation-field-dependent bias shift of the YIG hysteresis loop was observed. The complex modulation of the magnetic behavior originated from the magnetic coupling of the antiferromagnetic CoO and an additional interfacial coupling of the ferromagnetic CoOx. Depth-profiling X-ray photoemission spectroscopy revealed the nonuniform stoichiometric distribution in the 20-nm CoOx layer, which confirmed the origin of the various magnetic coupling effects on the bottom YIG layer. The comparative ferromagnetic resonance measurements also demonstrated the considerable magnetic coupling effect on the dynamic magnetism of the YIG.

Neuropeptide Substance P Enhances Skin Wound Healing In Vitro and In Vivo under Hypoxia.

Pressure ulcers (PUs) or sores are a secondary complication of diabetic neuropathy and traumatic spinal cord injury (SCI). PUs tend to occur in soft tissues located around bony prominences and may heal slowly or not at all. A common mechanism underlying impaired healing of PUs may be dysfunction of the local neurovascular system including deficiency of essential neuropeptides, such as substance P (SP). Previous studies indicate that disturbance in cutaneous sensory innervation leads to a defect in all stages of wound healing, as is the case after SCI. It is hypothesized that nerve fibers enhance wound healing by promoting initial inflammation via the releasing of neuropeptides such as SP. Therefore, we investigated whether exogenous SP improves skin wound healing using in vitro and in vivo models. For in vitro studies, the effects of SP on keratinocyte proliferation and wound closure after a scratch injury were studied under normoxia (pO2 ~21%) or hypoxia (pO2 ~1%) and in presence of normal serum (10% v/v) or low serum (1% v/v) concentrations. Hypoxia and low serum both significantly slowed cell proliferation and wound closure. Under combined low serum and hypoxia, used to mimic the nutrient- and oxygen-poor environment of chronic wounds, SP (10−7 M) significantly enhanced cell proliferation and wound closure rate. For in vivo studies, two full-thickness excisional wounds were created with a 5 mm biopsy punch on the dorsum on either side of the midline of 15-week-old C57BL/6J male and female mice. Immediately, wounds were treated topically with one dose of 0.5 μg SP or PBS vehicle. The data suggest a beneficial role in wound closure and reepithelization, and thus enhanced wound healing, in male and female mice. Taken together, exogenously applied neuropeptide SP enhanced wound healing via cell proliferation and migration in vitro and in vivo. Thus, exogenous SP may be a useful strategy to explore further for treating PUs in SCI and diabetic patients.

Palaeoenvironmental reconstruction and evidence of marine influence in Permian coal-bearing sequence from Lalmatia Coal mine (Rajmahal Basin), Jharkhand, India: A multi-proxy approach

Lalmatia coal-bearing sequences belong to the Barakar Formation (Permian) of Lower Gondwana. The well-developed coal-bearing sequences (approx. 52 m) exposed along the mine section have been studied to understand the depositional environment. Along with this, a cuticle study was performed to understand the palaeoclimate with the help of the stomatal index. The distribution of n–alkanes (n–C15 to n–C31) suggests major higher plant and algal dominant source input, although variations are seen in the relative input. Steranes identified include C29 regular sterane and 4-Methylsteranes. The Pr/Ph ratio varied from 0.43 to 4.26. Warm temperate to subtropical palaeoclimate with fresh to brackish water bodies, and reducing oxygen-poor environment were inferred from the Rb/Sr, Sr/Cu, Th/U, Sr/Ba, V/(V+Ni). Mean δ13C value measured is −23.0‰ ± 0.60‰ for coal and −22.6‰ for shale. These values are well correlated with typical δ13C values of the Permian coal and shale. The stomatal index of Glossopteris leaves (280 million years) was taken into account, and it showed a value of 10.7 that assumes a higher level of atmospheric CO2 during the Barakar Formation (Artinskian age). The result also shows that Permian taxon Glossopteris can be used for CO2–proxy during Permian age. The geochemical evidence suggests that towards the middle part (middle coal seam) of the studied section, the depositional milieu was under a marine-influenced marginal condition. The geochemical studies and carbon isotopic ratios unequivocally suggest that fluctuating climatic conditions existed during the deposition of the Lalmatia coal-bearing sequence.

Panagrolaimus superbus tolerates hypoxia within Gallium metal cage: implications for the understanding of the phenomenon of anhydrobiosis.

Panagrolaimus superbus nematodes are able to tolerate desiccation by entering into a peculiar state of suspended animation known as anhydrobiosis. When desiccated, anhydrobiotic organisms are also able to tolerate other physical stresses, as high and low levels of temperature and pressure. Here, we decided to investigate the tolerance of desiccated P. superbus to an unprecedented double stress – hypoxia within 99.99% Gallium (Ga) metal cage. The authors observed that regardless of the external relative humidity, desiccated P. superbus tolerated 7 d confined within the metal cage, displaying no negative effects on its survival and population growth rates over 40 d. The results evidence that anhydrobiosis also renders nematodes tolerant to otherwise lethal concentrations of Ga, in an oxygen-poor environment; thus, expanding its polyextremotolerance profile.

Na site doping a pathway for enhanced thermoelectric performance in Na1−xCoO2; the case of Gd and Yb dopants

Doping is considered to be the main method for improving the thermoelectric performance of layered sodium cobaltate (Na1−xCoO2). However, in the vast majority of past reports, the equilibrium location of the dopant in the Na1−xCoO2’ complex layered lattice has not been confidently identified. Consequently, a universal strategy for choosing a suitable dopant for enhancing Na1−xCoO2’s figure of merit is yet to be established. Here, by examining the formation energy of Gd and Yb dopants in Na0.75CoO2 and Na0.50CoO2, we demonstrate that in an oxygen poor environment, Gd and Yb dopants reside in the Na layer while in an oxygen rich environment these dopants replace a Co in CoO2 layer. When at Na layer, Gd and Yb dopants reduce the carrier concentration via electron–hole recombination, simultaneously increasing the Seebeck coefficient (S) and reducing electric conductivity (σ). Na site doping, however, improves the thermoelectric power factor (PF), only in Na0.50CoO2. When replacing a Co, these dopants reduce S and PF. The results demonstrate how thermoelectric performance critically depends on the synthesis environment that must be fine-tuned for achieving any thermoelectric enhancement.

Airflow Organization in a Transformable Shelter

The environmental control system of a shelter can provide comfortable temperature, air velocity and fresh air supply for members indoor, protecting them from the extreme weathers or oxygen-poor environment in the field. A shelter with transformable walls will have a large available space including the core module and extended modules for diverse demands such as dining or sleeping. The airflows in such a limited space can be inevitably influenced by walls and furniture. In the study, a transformable shelter with top supply and bottom return air organization mode was taken as the research object. The air supply duct on the ceiling of the shelter was designed to uniform the supplying air quantity through each outlet by adding baffles in the duct. Baffles can also make the export winds nearly perpendicular to the duct wall. The indoor airflow velocity and temperature fields in the condition of people gathering for dinner were obtained by simulation, so as that in the condition of people scattering for sleeping. In the dining condition, the barriers to the uniform airflow and temperature are the crowd occupying the core module. In the sleeping condition, the dominating barriers are the walls between different modules. The airflows were uniformed between different modules by opening apertures across the partitions. In view of human comfort, a comprehensive evaluation of the air flow organization was given, which presents an essential reference for system design and optimization.

Análisis Tecno-Económico de Gasificación de Polietileno, caso en México

As a way to encourage the use of new technologies for the recycling of plastic, the research will obtain techno-economic data for the possible chemical recycling of plastics, the gasification of polyethylene. It was simulated in ASPEN PLUS parcel to technically and economically analyze the viability of the gasification process, taking into account the restrictions and considerations of said process. The main plastic waste that is disposed of in landfills are polyethylene terephthalate, polystyrene and low and high density polyethylene. Gasification is a thermochemical process in which a carbonaceous substrate (in this case plastic) is transformed into a combustible gas through a series of reactions that occur in the presence of a gasifying agent (usually air) in an oxygen-poor environment. The work demonstrates the viability of this type of processes used in plastics such as high and low density polyethylene.