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OALib Journal期刊

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匹配条件: “ Sedimentation Coefficient” ,找到相关结果约3942条。
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Changes in Molecular Structure and Physicochemical Properties of Wheat Starch Affected by High Temperature and Shear
M. Majzoobi,A. Farahnaki
Journal of Science and Technology of Agriculture and Natural Resources , 2008,
Abstract: In this research the effects of two common cooking processes of foods, namely, autoclave and extrusion cooking on the molecular and physicochemical properties of wheat starch were investigated. The results showed that the solubility of the autoclaved samples increased with increasing the temperature while their relative viscosity decreased. These findings indicated that the molecular degradation of starch could occur during autoclave cooking. Moreover, constant sedimentation coefficient (s-value) of amylose and decreasing the s-value of amylopectin with increasing the temperature further confirmed degradation of amylopectin in particular. The results of the extruded samples showed that reduction in water content may increase the shear and pressure produced during extrusion cooking, which in turn could cause several changes in starch properties including degradation of starch granules, formation of amylose-lipid complex and degradation of amylopectin (as determined by reduction of the s-values). Also, reduction in water content could increase the puffiness of the final products and reduce the cold-water and final viscosities of the extruded samples. These observations may indicate the importance of the molecular studies of starch for better interpretation of physical changes of the final products.
The Probable Structure of “Form IV” (Alkali-Denatured Circular DNA)  [PDF]
Ken Biegeleisen
Open Access Library Journal (OALib Journal) , 2016, DOI: 10.4236/oalib.1103114
Abstract:
A detailed molecular model for alkali-denatured duplex circular DNA (“Form IV”) is proposed. The illustrative biological example used is the replicative form of fx174, a 5 kb duplex circular chromosome. The model explains all of Form IV’s known and peculiar features. In a sedimentation coefficient vs. pH titration, Form IV begins to appear at pH 12.3, at which point it can be persuasively argued that no further supertwists can be added to the already-highly-supertwisted chromosome. Therefore a new structure must appear. The sedimentation coefficient s then undergoes a massive, but initially reversible increase as the pH is raised further, culminating at pH 12.8 with a 250% increase. This degree of compactness can only be explained by a 4-stranded tetraplex structure, consisting of a pair of duplexes whose base pairs are mutually intercalated. Above pH 12.8, the structural changes become irreversible, suggesting a further conformational change. It is proposed that this involves an axial rotation of the component duplex strands, so that the bases now stack on the outside, and the phosphate groups lie in the core, where they bond ionically by means of salt bridges. When the irreversibly denatured compact structure is neutralized at moderate-to-high salt concentrations, a third novel structure appears, which has a sedimentation coefficient midway between the native 21 s and the denatured 50 s. It is proposed that this is a hybrid structure; part tetraplex, part duplex. To return to a fully-duplex form, it is necessary to both neutralize the solution, and also to greatly reduce the ionic strength, i.e., to the range 0.001-0.01 M. Since the DNA, under those conditions, cannot possibly have normal complementary base-pairing, the duplex structure must either be tautomerically base-paired, or else stabilized solely by base-stacking, with no base-pairing at all.
Effects of Interparticle Potential on the Sedimentation of Monodisperse Colloid System
粒子间势力对单分散稳定系统粒子沉降的影响

Wang Hao,Wen Jingsong,
王浩
,温景嵩

大气科学 , 1999,
Abstract: The effects of interparticle potential on the sedimentation of colloid system is still anunsolVed problem. An important difficult problem is how to formulate the interparticle potential in astable system. People can only depend on some models now. Here we investigate three previous modelsof interparticle potential and present a new and more reasonable method to deal with the interparticlepotential in monodisperse system. Moreover;; some numerical calculations are made and the results arecompared with experiments. The comparison shows that the new method is better than the previousones.
Incorporating sorption/desorption of organic pollutants into river water quality model
LOU Bao-feng,ZHU Li-zhong,YANG Kun,
LOU Bao-feng
,ZHU Li-zhong,YANG Kun

环境科学学报(英文版) , 2004,
Abstract: Preliminary research was conducted about how to incorporate sorption/desorption of organic pollutants with suspended solids and sediments into single-chemical and one-dimensional water quality model of Jinghang Canal. Sedimentation-resuspension coefficient k 3 was deduced; characteristics of organic pollutants, concentrations and components of suspended solids/sediments and hydrological and hydraulic conditions were integrated into k 3 and further into river water quality model; impact of sorption/desorption of organic pollutants with suspended solids and sediments on prediction function of the model was discussed. Results demonstrated that this impact is pronounced for organic pollutants with relatively large K oc and K ow, especially when they are also conservative and f oc of river suspended solids/sediments is high, and that incorporation of sorption/ desorption of organic pollutants into river water quality model can improve its prediction accuracy.
Analysis of Structures for Water Treatment from Suspended Contaminants
Prof. dr. habil. Viktor Georgijevch Ponomarev
Environmental Research, Engineering and Management , 2012, DOI: 10.5755/j01.erem.61.3.1199
Abstract: This article deals with the problem of the analysis of structures for sewage treatment from suspended contaminants, there are listed the results confirming the dependence of the process of their separation on a majority of natural indicators with a correlation in between; there is proposed an index characterizing the stability of suspensions to the separation process and there is also considered the effect of the hydraulic and hydrodynamic regimes of streams in structures on this process; there is given an example of designing a construction that includes these factors; in this article there was put forward a hypothesis of possible development of the unified model of analysis of structures applied for separation of suspended contaminants. DOI: http://dx.doi.org/10.5755/j01.erem.61.3.1199
ESTIMATION OF SEDIMENTATION OF GONDUR TANK WITH THE HELP OF G.I.S. TECHNIQUE
WAGH SUNIL GHANASHYAM,WAGH RAJESH VASANTRAO,BHAMARE S.M
Golden Research Thoughts , 2012, DOI: 10.9780/22315063
Abstract: India is continental land fulfill its water requirement from the monsoon rainfall which is uncertain with its intensity and time.In satisfying the need of agriculture, drinking water, industrial supply of water, dams are playing very important role. These tanks are suffering from the problem of sediment deposition which leads to decline the storage capacity of water with successive proceeding year.The Gondur tank is situated at Gondur village in Dhule taluka near Dhule city. This paper attempts to estimate the sedimentation with GIS techniques. It is estimated that sedimentation since from 1965 to 2010 is near about 378.35 metric tons and ground level rises near about 2.35 mt.
Sedimentation rate in dengue: an explanation based on proposed hypothesis on weight and erythrocyte sedimentation
Viroj Wiwanitkit
Iranian Journal of Medical Hypotheses & Ideas , 2010,
Abstract: "nDengue is an important mosquito borne viral infection. Focusing on the hematological finding in dengue, the erythrocyte sedimentation rate is varied. The exact explanation for this observation is unclear. Here, the author uses the previously already proposed hypothesis on weight and erythrocyte sedimentation for giving explanation of the observed sedimentation in dengue. This new explanation can fit with the already published observation in medical literature and indicates that erythrocyte sedimentation rate might be a useful predictor and classifier for kinds of dengue based on its severity.
Orogenesis: Cause of Sedimentary Formations  [PDF]
Guy Guy Berthault
Open Journal of Geology (OJG) , 2013, DOI: 10.4236/ojg.2013.32B005
Abstract:

Experiments on stratification discussed here have revealed the mechanical nature of lamination as well as the role of turbulent current as agent of stratification. They challenge Steno’s principle that superposed strata are successive sedimentary layers. They show that relative chronology should not be referred to as “stages” but as “sequences” of series. The rock formation studied by Lalomov shows that the duration of sedimentation could be considerably shorter than indicated by the Geological Time Scale. The latter scale corresponds to large marine transgressions and regressions that can result from the shift of polar axis following such major orogeneses as the Caledonian, Hercynian and Alpine.

Separation of Fe3O4 Nanoparticles from Water by Sedimentation in a Gradient Magnetic Field  [PDF]
I. Medvedeva, Iu. Bakhteeva, S. Zhakov, A. Revvo, M. Uimin, A. Yermakov, I. Byzov, A. Mysik, N. Shchegoleva
Journal of Water Resource and Protection (JWARP) , 2015, DOI: 10.4236/jwarp.2015.72009
Abstract: Sedimentation dynamics of magnetite (γ-Fe3O4) nanopowders (10 - 20 nm) in water in the presence of a gradient magnetic field was studied by optical and Nuclear Magnetic Resonance (NMR) relaxometry methods. The magnetic field B ≤ 0.3 T, dB/dz ≤ 0.13 T/cm was produced by the system of permanent strip magnets. The initial sedimentation rate of the nanoparticles in water and under magnetic fields is higher for less concentrated suspensions (c0 = 0.1 g/l) than for more concentrated ones (c0 = 1 g/l). This might be connected with the formation of gel structures due to strong magnetic attraction between ferromagnetic nanoparticles. In the gravitation field, the suspensions of the particles (10 - 20 nm) remain stable for over 20 hours. The sedimentation process can be greatly accelerated by the action of a vertical gradient magnetic field, reducing the sedimentation time down to several minutes. In a gradient magnetic field enhanced by a steel grid, sedimentation of the nanopowder (c0 = 0.1 g/l) for 180 minutes resulted in reduction of the iron concentration in water down to 0.4 mg/l. In flowing water regime, the residual iron concentration in water 0.3 mg/l is reached after 80 minutes.
Tidal Flat Sedimentation and Event

科学通报(英文版) , 1994,
Abstract:
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