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The Runoff Changes and Influential Factors Analysis of Wulanmulun River
Get PDFIn the past 60 years, climate change and increasingly extensive human activities have greatly altered the runoff in Wulanmulun River basin. Based on the climate and hydrological data in Wangdaohengta station during 1959 - 2015, runoff variation characteristics and the influencing factors were studied. Mann - Kendall trend analysis, statistic analysis, R / S analysis, and double mass curve were used comprehensively in the study. The results indicated that the multi - year change of runoff had a decreased tendency in all, and this trend was the most evident since the end of the twentieth century. The runoff affected by rainfall and human activities appeared three change periods in which the turning years were 1980 and 1995 respectively. The effect of precipitation on runoff decreased, and the influence rate reduced from 18.77% in 1980 - 1995 to 8.48% in 1995 - 2015. The influence of human activities on runoff gradually increased, the influence rate increased from 81.23% in 1980 - 1995 to 91.52% in 1995 - 2015. The Hurst index was 0.3533 for the Wangdaohengta station which indicates that the runoff of Wulanmulun River will have a raise trend in the future
Research on mechanical performances and deformation mechanism of steel irregular joint
Get PDF According to an analysis of the mechanical behaviour of irregular joints between steel box columns and beams such as ductility, ultimate bearing capacity, degradation of strength and stiffness, energy dissipation, the deformation mechanism of the steel irregular joint panel zone is established based on the plastic hinge theory. Experimental study results indicate that irregular joints between steel box columns and beams exhibit good seismic performance and energy dissipation capacity. Ductility is consistent with the requirements of plastic ultimate deformation; bearing capacity degradation of all specimens is not significant when the displacement of the layer exceeds the ultimate displacement. Strength and stiffness degradation of all specimens are not notable when the interstory displacement exceeds ultimate displacement. The experimental results indicate that shear buckling failure in the small core area of the panel zone is the main failure mode
Mixed Convection of Hybrid Nanofluids in an Annulus
Get PDF In this study, mixed convection in an annulus formed by two horizontal isothermal cylinder surfaces and filled with hybrid nanofluids was examined with Galerkin weighted residual finite element method. The outer cylinder is rotating and inner cylinder is stationary. Influence of Rayleigh number, angular rotational speed of the outer cylinder, eccentricity of the inner cylinder, solid volume fractions of different nanoparticles (alumina, copper, hybrid particles between 0 and 0.02) on the fluid flow and heat transfer characteristics were analyzed. It was observed that average heat transfer enhances with Rayleigh number, solid volume fractions of nanoparticles and eccentricity ratio and reduces as the angular rotational speed of the outer cylinder increases. Adding nanoparticles was found to be advantageous for lower values of Rayleigh number and higher values of angular rotational speed. At the highest volume fraction of Cu nanoparticles, average Nusselt number increases by 31.75 % when the inner cylinder center moves in +y direction. Nanofluid with hybrid nanoparticles gives heat transfer rates which are higher than that of with alumina and lower than that of with copper nanoparticles for the same volume fraction
Applied Research of Cleaner Production Evaluation System in Wig Industry
Get PDFAn assessment indicator system of cleaner production in wig industry was built in this article, which intended to meet the shortage of corresponding standards of cleaner production evaluation in the national wig industry. An assessment route of cleaner production index system of the wig industry was established. Based on analysis of the production process and pollution node of the wig industry, the cleaner production index system of wig industry was established for the first time, which contained 6 first-level indicators and 22 second-level indicators. The evaluation indicator baselines were set out in accordance with the cleaner production standards and index systems in other areas when the actual data of each index of the wig enterprises was analyzed statistically. Then, the importance of every index was confirmed by analytic hierarchy process (AHP) and an AHP-Fuzzy comprehensive evaluation model was introduced by utilizing the fuzzy mathematics method. What is more, in order to test and verify the accuracy of the evaluation system, this evaluation system was applied to estimate the cleaner production level of a wig enterprise in Henan province. It was found that the advanced level of this wig company should be 0.1352, as against the membership of the general level was 0.0391, which could be compared to the basic level of 0.0298. The result is consistent with the actual situation of the enterprise, which proves that the system is feasible and can be used to tap the cleaner production potential of wig enterprises and promote the sustainable development of the wig enterprises
Antioxidants and Antioxidant Capacity in Leafy, Stem, and Fruit Vegetables Including 50 Species
Get PDFEpidemiological studies have confirmed that high intake of fruits and vegetables is associated with low incidence of many kinds of diseases, which are hypothesized to be owing to antioxidants in fruits and vegetables. In this study, three types (leafy, stem, fruit) vegetables including 50 species were systematically evaluated for their antioxidant capacity (AC) and antioxidants including total phenolic compound (TPC), total flavonoids (TF), and L-ascorbic acid (LAA). Results showed that vegetables types had no significant effects on antioxidants. Vegetables with vivid color like purple cabbage, purple dolichos lablab, purple cowpea, red pepper, yellow pepper, lotus root, and ginger ranked high in their antioxidants (TPC 32.76-117.63 mg gallic acid/g FW, TF 25.78-152.96 mg rutin/100g FW, LAA 69.11-165.44 mg/100g FW) and AC (FRAP 69.38-109.13 μmol Fe2+/100gFW, ABTS 2.19-3.75 μmol Trolox/gFW). Relatively, crown daisy, endive, celery stem, and cucumber had low antioxidants (TPC 2.66-6.29 mg gallic acid/g FW, TF 10.37-37.56 mg rutin/100g FW, LAA 14.64-39.44 mg/100g FW) and AC (FRAP 1.99-10.81 μmol Fe2+/100gFW, ABTS 0.39-0.68 μmol Trolox/gFW). TPC and LAA had strong positive correlations with AC regardless of vegetable types, while TF was positively related to AC only in leafy vegetables. The result would be valuable for both epidemiological research and dietary guidelines as these vegetables are affordable and widely available
Quality Change of Postharvest Okra at Different Storage Temperatures
Get PDFIn order to analyze the influence of temperature on the storability and postharvest quality properties of okra, the postharvest okra was stored at 4 or 25°C and the changes of weight loss rate, firmness, and the contents of soluble protein, chlorophyll and vitamin C were determined. For 5 days, the weight loss of okra was about 0.94% and 13.74% stored at 4 and 25°C, respectively. The firmness of the fruit at 25°C declined by 36.04% after 5 days storage and decreased by 17.59% at 4°C. Soluble protein of okra at stored 4 and 25°C was 0.97 mg/g and 0.67 mg/g after 5 days, respectively. The chlorophyll content at 4°C was 7.76 mg/100 g after 5 days, compared with that at 25°C, decreased from the initial 16.32 to 4.54 mg/100 g. The vitamin C of okra fell by 35.60 mg/100 g after 5 days of storage at 4°C, which is significantly higher than that stored at 25°C, declining 17.97 mg/100 g by 5 days. Therefore, cold storage at 4°C play an important role in the maintenance of okra edible quality
Preparation and Photocatalytic Activity of Fe3+ - doped TiO2 Modified
Get PDFPhotocatalytic materials of TiO2 / coarse silica gel microspheres were prepared by sol-gel impregnation method and doped with transition metal ions Fe3+ to form Fe3+ modified TiO2 / coarse silica gel microspheres. The surface of the Fe modified photocatalytic materials were analyzed by XRD and surface scanning. Degradation of reactive dyes using X-3B dye wastewater water samples for validation tests. The results show that the photocatalytic activity of the photocatalytic material reaches the best when the Fe doping amount is 0.5%, and the most photocatalyst amount is 10g / L. The degradation rate of COD under this dosage was 72.32%. At the same time, according to the characterization analysis, it was found that Fe did not react with the photocatalytic material of TiO2 / coarse silica microspheres in the reaction, Fe increased the defect structure of TiO2 surface and promoted the formation of anatase, A red shift occurred and the corresponding range of the spectrum expanded toward the visible region. The results show that the doping of Fe affects the formation of TiO2 crystals, but increases the photocatalytic efficiency of TiO2
Effect of Polymerization Time and Pressure on the Molecular Weight and Molecular Weight Distribution of Polyethylene
Get PDFMolecular weight and molecular weight distribution (MWD) of polyethylenes (PE) are important in determining their physical, mechanical, and rheological properties of end-products. In principle, molecular weight controls the mechanical properties of polymers, while MWD mainly affects the rheological properties. Therefore, it is necessary to control molecular weight and MWD to optimize the property and processibility of PE. The conventional Ziegler-Natta catalyst is still the main industrial catalyst for the production of PE. Hence, the control of MWD of PE produced using Ziegler-Natta catalyst has always been one of the most worthy research targets for industry and academy. The influence of the polymerization time and pressure on the molecular weight, MWD and relative MWD of PE in the ethylene polymerization with a MgCl2/SiO2/TiCl4/AlEt3 catalyst system in the slurry phase was studied by using gel permeation chromatography (GPC). It has been found that with the lapse of time increases the molecular weight and MWD of PE. However, the increase of the polymerization pressure increases the molecular weight and decreases the MWD of PE
The Parameters of Composite Binders of Technogenic Waste from Russian Far East
Get PDFThe paper considers the process optimization of structure of cement stone due to the use of industrial waste, which allows to increase the strength characteristics of the binders. Proposed composite binders, obtained by co-grinding of cement, hyper plasticizer, fly ash and limestone crushing screenings. The connection of the seal structure of the composite binder with increasing hydration activity of the fine fraction of the mineral filler. The increased strength characteristics developed binders provided due to their high specific surface area with mechanic and chemically activated surface layers of filler grains and cement
Effects of high activator content on fly ash-based geopolymers exposed to elevated temperatures
Get PDFThis article reports the influence of high alkaline activator content on the compressive strength and microstructure characteristics of a fly ash (FA) geopolymer system after exposure to elevated temperatures of 400 °C, 600 °C, and 800 °C. The sequential changes in the geopolymer gel structure after exposure to elevated temperatures and their effects on the residual strength were investigated through scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the high strength of the FA geopolymers reduced after exposure to 400 °C and 600 °C and failed in return any strength after exposure to 800 °C. The SEM results showed that the high activator content generated large quantities of unreacted crystals composed mainly from silicate underwent viscous sintering process at range of temperatures of 600 °C to 800 °C, and swelling resulting in system failure. XRD results showed that the geopolymers exposed to 800 °C exhibited significant decomposition in the aluminosilicate phase and amorphous hump compared to unexposed pattern