Convergence of a discrete Oort–Hulst–Safronov equation

A discrete version of the Oort–Hulst–Safronov (OHS) coagulation equation is studied. Besides the existence of a solution to the Cauchy problem, it is shown that solutions to a suitable sequence of those discrete equations converge towards a solution to the OHS equation. Copyright © 2005 John Wiley & Sons, Ltd.     

The effectiveness of bisulfite-activated permanganate technology to enhance the coagulation efficiency of Microcystis aeruginosa

The effects of bisulfite-activated permanganate technology(PM/BS) as a pre-oxidation process on enhancing Microcystis aeruginosa(M.aeruginosa) removal by post coagulation were investigated.The results demonstrated that pretreatment with PM/BS process effectively promoted the algae removal by coagulation with Al_2(SO_4)_3 as the coagulant and this phenomenon was more obvious with the increase of water hardness.Compared to the sole coagulation,PM/BS pre-oxidation combing with coagulation could neutralize the zeta potential of algal cells effectively,decrease the algal cell size,and lead to the formation of more compact flocs due to the in-situ generated Mn02.The effect of oxidant dosages on algal organic matter(AOM) was also studied and no obvious release of macromolecular substances was observed with the dosage of KMn04 increasing from 3.0 mg/L to 7.0 mg/L,suggesting the integrity of algal cells at a high KMn04 dosage.Moreover,PM/BS pre-oxidation could lead to the decrease of most analyzed disinfection by-products(DBPs) at a Al_2(SO_4)_3 dosage of 40.0 mg/L.The algae removal efficiency was also significantly enhanced by PM/BS pre-oxidation in the test using real algae-laden water.This study indicated that PM/BS process might be a potential assistant technology for algae removal by subsequent coagulation.     

Coagulation and fragmentation with discrete mass loss

A nonlinear integro-differential equation that models a coagulation and multiple fragmentation process in which discrete fragmentation mass loss can occur is examined using the theory of strongly continuous semigroups of operators. Under the assumptions that the coagulation kernel K is bounded and the fragmentation rate function a satisfies a linear growth condition, global existence and uniqueness of solutions that lose mass in accordance with the model are established. In the case when no coagulation is present and the fragmentation process is governed by power-law kernels, an explicit formula is given for the substochastic semigroup associated with the resulting mass-loss fragmentation equation.     

The influence of molecular mass of sulfated propylene glycol ester of low-molecular-weight alginate on anticoagulant activities

Sulfated propylene glycol ester of low-molecular-weight alginate (PSS) was fractionated by low-pressure gel permeation chromatography. Four fractions (PSS1-4) with different weight-averaged molecular mass (51.95, 25.62, 11.76 and 5.41 kD, respectively) were obtained and their structural characteristics were determined and compared by Fourier transform infrared and nuclear magnetic resonance spectroscopes. Their anticoagulant activities were also studied by evaluating their influence on the activated partial thromboplastin time, thrombin time, anti-thrombin and anti-FXa factor activities mediated by anti-thrombin III and heparin cofactor II. The results demonstrated that PSS1-4 had similar structural parameters, such as the degree and pattern of sulfation and backbone, but their molecular masses were different. The bioassay results suggested that the anticoagulation was molecular mass dependent. PSS1 and PSS2 strongly inhibited the activity of thrombin mediated by heparin cofactor II and anti-thrombin III, whereas PSS4 only showed a very weak anti-thrombin activity. PSS1-3 weakly inhibited the activity of coagulation factor Xa mediated only by anti-thrombin III while PSS4 lacked the anti-Xa activity.     

带有碰撞爆炸的离散的凝结方程密度守恒解的唯一性

在条件aij≤Amin{i，j}，i，J≥1(其中A是非负常数)成立的情况下，证明了带有碰撞爆炸的离散的凝结方程的密度守恒解是唯一的，所获得的结论改进了已有的结果．     

Analytic Fragmentation Semigroups and Classical Solutions to Coagulation–fragmentation Equations——a Survey

In the paper we present a survey of recent results obtained by the author that concern discrete fragmentation–coagulation models with growth. Models like that are particularly important in mathematical biology and ecology where they describe the aggregation of living organisms. The main results discussed in the paper are the existence of classical semigroup solutions to the fragmentation–coagulation equations.     

Adsorption kinetics,mechanistic, isotherm and thermodynamics study of petroleum produced water coagulation using novel Egeria radiate shell extract (ERSE)

BackgroundThe mechanistic and adsorptive component of petroleum produced water (PPW) coagulation has been studied, using novel Egeria radiata shell extract (ERSE).MethodsPhysiochemical and instrumental characterization of the precursor (Egeria Radiata Shell, ERS) and bio-coagulant were studied. Effects of process parameters on treatment efficiency and rate-determining step for the particles decontamination were investigated. The coag-flocculation data obtained were analyzed in the light of adsorption kinetics, mechanistic modeling, isotherm and thermodynamics studies.Significant findingsEvidenced results from the characterization showed that extracted coagulant (ERSE) possessed significant properties required to drive surface phenomenon process. Surface morphology and thermo-gram profile revealed significant porosity and thermal stability, respectively for ERSE. The highest adsorption capacity of 2068.132 ?mg/g was obtained at 5 ?g/L, 30 ?min, pH 4 and 45 ?°C. The adsorption regime was spontaneous, physically predominated and best described by the pseudo second order kinetic and Langmuir isotherm models. The thermodynamic analysis confirmed the process to be endothermic and entropy driven. High grade ERSE successfully demonstrated adequate treatment of the PPW at 90.9% efficiency, while maintaining significant influence of adsorption on the coagulation process. Moreover, the total cost of treating 1 ?L of PPW (involving material cost and electricity) was determined to be 3.8 $. Also, the costs of ERSE optimal dosage of 5 ?g/L preparation and energy are 0.3 and 3.5 $, respectively. Summarily, ERSE can be applied in effective decontamination of PWW.     

An evaluation of mass,number concentration,chemical composition and types of particles in a cafeteria before and after the passage of an antismoking law

This study assessed air quality indicators before and after enactment of the Spanish anti-smoking law. Mass and number concentrations and the chemical composition of particles were evaluated. Microscopy analyses were also conducted. Real time concentrations of PM₁₀, PM_2.5, PM₁ and ultrafine particles were measured under ventilated and non-ventilated conditions and PM₁₀ samples were collected for detailed inorganic and organic chemical characterization. Before enactment of the law in 2010, tobacco smoke produced significant indoor ambient particulate matter pollution, with elevated particulate matter mass concentrations (PM₁₀ and PM₁ concentrations of 122–220 and 48–85 μg/m³, respectively) and ultrafine particle numbers (75,000 and 48,000 cm^–3 under ventilated and non-ventilated conditions, respectively). Typical tobacco smoke tracers including iso- and anteiso-alkanes and elements including La and Ce from the ignition of lighters were abundant. Additionally, several toxic substances derived from tobacco smoke, including Cd (3.1 ng/m³) and benzo[a]pyrene (1.0 ng/m³) were present at concentrations approximately 10 times greater than those measured after enactment of the anti-smoking law. The anti-smoking law significantly reduced exposure to potentially toxic compounds by approximately 90%. This law is expected to have a positive health impact, particularly for people who spend considerable time in affected environments, such as employees.     

On a mathematical model for laser-induced thermotherapy

We study a mathematical model for laser-induced thermotherapy, a minimally invasive cancer treatment. The model consists of a diffusion approximation of the radiation transport equation coupled to a bio-heat equation and a model to describe the evolution of the coagulated zone. Special emphasis is laid on a refined model of the applicator device, accounting for the effect of coolant flow inside. Comparisons between experiment and simulations show that the model is able to predict the experimentally achieved temperatures reasonably well.     

柠檬酸钠对谷氨酰胺转移酶山羊乳凝胶特性影响的光谱学分析

运用多重光散射光谱、多散斑扩散波光谱和动态光散射光谱分析了柠檬酸钠(TSC)对谷氨酰胺转移酶(TG酶)山羊乳凝胶特性的影响。将浓度分别为0,20,40,60和80 mmol·L-1 的TSC加入到脱脂羊乳中,经过TG酶处理后进行酸化凝乳。凝乳形成过程中,动态光散射光谱显示,随着TSC浓度的增加,酪蛋白胶束的直径从(142.0±11.2) nm下降到(24.4±2.1) nm;在凝胶形成的前5 h内,在不同TSC浓度条件下,样品的背散射光强度分别从41.9%±0.3%,35.8%±0.4%,25.3%±0.5%,10.6%±0.3%和5.3%±0.4%,增加到55.8%±0.6%,49.5%±0.5%,41.9%±0.4%,37.8%±0.4%和30.8%±0.3%,表明TSC的浓度越高,凝胶体系中颗粒的尺寸越小,形成的凝胶构筑单元越小;同时,多散斑扩散波光谱的均方位移曲线显示,凝胶的突变时间分别为31,74,98,151和226 min,表明TSC的浓度越高,山羊乳凝胶形成时间越长;凝胶的持水力与硬度值分析发现,TSC将羊乳酪蛋白胶束分解成更小的颗粒,在TG酶作用下形成更多的共价键连接位点,形成的凝胶具有更高的硬度和持水能力。