Single flow treatment degradation of antibiotics in water using falling-film dielectric barrier discharge

The environmental contamination caused by antibiotics is increasingly conspicuous due to their widespread manufacture and misuse. Plasma has been employed in recent years for the remediation of antibiotic pollution in the environment. In this work, a falling-film dielectric barrier discharge was used to degrade the antibiotic tetracycline(TC) in water. The reactor combined the gas-liquid discharge and active gas bubbling to improve the TC degradation performance. The discharge characteristics, chemical species’ concentration, and degradation rates at different parameters were systematically studied. Under the optimized conditions(working gas was pure oxygen, liquid flow rate was 100 mL/min, gas flow rate was 1 L/min,voltage was 20 kV, single treatment), TC was removed beyond 70% in a single flow treatment with an energy efficiency of 145 mg/(kW·h). The reactor design facilitated gas and liquid flow in the plasma area to produce more ozone in bubbles after a single flow under pure oxygen conditions, affording fast TC degradation. Furthermore, long-term stationary experiment indicated that long-lived active species can sustain the degradation of TC. Compared with other plasma treatment systems, this work offers a fast and efficient degradation method, showing significant potential in practical industrial applications.

Study on water treatment effect of dispersion discharge plasma based on flowing water film electrode

To improve the utilization rate of plasma active species,in this study,a closed non-uniform air gap is formed by a flowing water film electrode and a sawtooth insulating dielectric layer to realize the diffuse glow discharge in the atmosphere.Firstly,the electric field distribution characteristics of non-uniform air gap in the sawtooth dielectric layer are studied,and the influence of aspect ratio on the characteristics of diffuse discharge plasma is discussed.Subsequently,the effects of wire mesh,the inclination angle of the dielectric plate,and liquid inlet velocity on the flow characteristics of the water film electrode are analyzed.The results show that the non-uniform electric field distribution formed in the sawtooth groove can effectively inhibit the filamentous discharge,and the 1 mm flowing water film is directly used as the electrode,and high-active plasma is formed directly on the lower surface of the water film.In addition,a plasma flowing water treatment device is built to treat the methyl orange solution and observe its decolorization effect.The experimental results show that after 50 min of treatment,the decolorization rate of the methyl orange solution reaches 96%,which provides a new idea for industrial applications of wastewater treatment.

Performance of a Horizontal Flow Constructed Reed Bed Filter for Municipal Wastewater Treatment: The Case Study of the Prototype Installed at Gaston Berger University, Saint-Louis, Senegal

In Saint-Louis, Senegal, a constructed wetland with horizontal flow reed beds (FHa and FHb) has demonstrated significant efficacy in treating municipal wastewater. Analyzing various treatment stages, the system showed only a slight temperature variation, from an influent average of 26.3°C to an effluent of 24.7°C. Electrical conductivity decreased from 1331 mS/cm to 974.5 mS/cm post-primary treatment, with suspended solids (SS) dramatically reduced from 718.9 mg/L to 5.7 mg/L in the final effluent. Biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) saw a notable decrease, from initial levels of 655.6 mg/L and 1240 mg/L to 2.3 mg/L and 71.3 mg/L, respectively. Nitrogenous compounds (N-TN) and phosphates () also decreased significantly, indicating the system’s nutrient removal capacity. Microbiological analysis revealed a reduction in fecal coliforms from 7.5 Ulog/100ml to 1.8 Ulog/100ml and a complete elimination of helminth eggs. The presence of Phragmites and Typha was instrumental in enhancing these reductions. The system’s compliance with the Senegalese standards for disposal into natural environments, WHO recommendations for unrestricted water reuse in irrigation, and the European legislation for water reuse was established. The effluent quality met the stringent criteria for various classes of agricultural reuse, illustrating the system’s potential for sustainable water management. This wetland model presents a robust solution for water-stressed regions, ensuring environmental protection while supporting agricultural needs. The study calls for ongoing research to further refine the system for optimal, reliable wastewater treatment and water resource sustainability.

Application of High-efficient Vertical Flow Constructed Wetland in Treatment of Domestic Sewage in Residential Community

With the increase of requirement for ecological function of environment,for quality of water environment,for sewage treatment cost and for comprehensive utilization of water resources,it was bound to introduce a new type of ecological technology for pollution treatment which was low in cost,convenient in management and stable in operation.High-efficient vertical flow constructed wetland developed by Shenzhen Academy of Environmental Science was characterized by good landscape effect and high efficiency of pollutants removal,and it had been widely applied in sewa-ge treatment and recycling and in lake water circulation purification.A lot of practical results showed that this technology could achieve high removal efficiency of SS,COD,BOD5,NH4-N and TP and the removal rate had arrived at more than 80% when hydraulic loading was 0.33-0.50 m/d.Effluent quality had met the water quality standard for recycling of urban sewage.

Baosteel's Slag Short Flow process for molten steelmaking slag treatment and its application

Baosteel＇ s Slag Short Flow（BSSF） is an innovative process for steelmaking slag treatment that was developed by Baosteel. The process principles, flow-chart, parameters and component systems of the BSSF for steelmaking slag treatment are presented. Characteristics of the finished BSSF slag are summarized by analyzing the slag＇ s physical and chemical performances. Several Utilization methods for the BSSF slag are given.

Nitrification Performance in Lab Scale Biological Treatment System： Effect of Flow Rates

Lab scale biological treatment system was constructed from acrylic and operated using synthetic wastewater to evaluate the nitrification performance using different media. The media used for were Ceramic Ring A （CRA）, Ceramic Ring B （CRB）, Japanese Filter Mat （JFM）, and Filter Wool （FW）. Laboratory studies were conducted, in order to evaluate the nitrification performance of different media types, at different synthetic wastewater flow rates, ranging from 0.03 to 0.045 m3/hr. The results from experiments suggest that at higher water flow rates, there was a decrease in nitrification for all media types. Based on the ammonia and nitrite removal rates, FW media gave the optimum nitrification, of up to 0.46 g/m2/day and 0.09 g/m2/day, respectively. Besides, in this study, the surface texture of the media is the main factor that affected the volumetric ammonia and nitrite conversion rates （VTR and VNR）. JFM gave the greatest VTR and VNR performance, compared with the other media

NUMERICAL INVESTIGATION OF AXIAL FLOW COMPRESSOR CASING TREATMENT

Using an inviscid model with inlet total pressure gradient and a J. D. Denton scheme, this paper for the first time numerically solves the 3D flow field of compressor casing treatment, and also explores some boundary singularities and numerical stability. Agreement is attained in qualitative explanations of some, casing treatment test results and its mechanism.

Significance of Primary Treatment Selection in the Efficiency of Wastewater Treatment in Constructed Wetlands (CWs)

This research explores strategies to enhance the efficiency of secondary treatment in Vertical Flow Constructed Wetlands (CW) in Montenegro. The focus is on selecting appropriate primary treatment methods alongside three distinct substrate types to improve wastewater treatment efficacy. The study examines the combination of two primary treatments with different substrate types in constructed wetlands (CW1, CW2, and CW3). The primary treatments include the existing wastewater treatment plant (WWTP) in Podgorica, involving coarse material removal through screens, inert material separation in aerated sand traps, and sediment and suspended matter removal in primary sedimentation tanks. The Extreme Separator (ExSep) was employed to evaluate its efficacy as a primary treatment method. The research demonstrates that the efficiency of CW can be significantly enhanced by selecting suitable primary treatment methods and substrates in Podgorica’s conditions. The most promising results were achieved by combining ExSep as a primary treatment with secondary treatment in CW-3. The removal efficiencies after CW3 for COD, BOD, and TSS exceeded 89%, 93%, and 91%, respectively. The outcomes underscore the significance of primary treatment in mitigating pollutant loads before discharge into the constructed wetlands, emphasizing potential areas for further optimization in wastewater treatment practices to enhance environmental sustainability and water quality management.

两机flow-shop类型模具热处理车间批调度算法

总结模具热处理车间生产调度的特点,在工件动态到达的情况下,研究了两阶段均为批处理机、各批次加工时间为定值的流水车间批调度问题。以最小化最大完成时间为目标建立混合整数规划数学模型,证明问题是NP难并给出最优目标函数值的下界,构建并证明一种求解大规模问题最优解的算法。算法首先求解分批数量上下界,然后构造数学模型并求解在给定分批数量下对应的最优解,最后通过对比各给定分批数量下得到的解并得到全局最优解。对于小规模问题,通过与传统分枝定界法得到的最优解相比较,说明所提算法能得到问题的最优解且计算时间更短;对于大规模问题,在不同生产状况下随机产生多组数据、对所提算法进行验证,结果显示该算法是有效的。

Dyract flow流动复合体和光固化窝沟封闭剂3年效果评价

目的 :评价Dyractflow流动复合体用于窝沟封闭剂的临床应用价值及其效果。 方法 :对 3 60例 6～10岁患者的 72 0个上、下颌第一恒磨牙用Dyractflow流动复合体进行窝沟封闭术 ,并采用可见光固化窝沟封闭剂自身对照的研究方法评价效果。结果 :随诊 3年后发现Dyractflow流动复合体组在术 1、2、3年的涂膜保留率均比可见光固化组高 (P <0 .0 1)。但龋病患病率无显著性差异 (P >0 .0 5 )。结论 :Dyractflow流动复合体是一种可靠的窝沟封闭剂 。

预防性Dyractflow流动复合体充填窝沟龋的临床效果

目的:观察评价Dyract flow 流动复合体用于窝沟可疑龋、初龋预防性充填的临床疗效.方法:对145 例7～24 岁患者的(牙合)面窝沟龋在磨除龋损的牙体组织后,用 Dyract flow 流动复合体对龋损部位及未龋损的窝沟区域作预防性充填封闭术,对侧同名牙或邻牙也有窝沟龋者用银汞合金充填作对照.结果:随访4 年后发现该方法充填材料保留率较高,能有效阻止龋病的进一步发展.其龋病及继发龋发病率与对照组有显著性差异.但充填材料保留率的远期效果不如银汞合金,在3、4 年时有统计学差异.结论:预防性Dyract flow 流动复合体充填术可作为治疗窝沟龋的银汞合金的替代治疗方法之一,长期随诊进行补涂效果则更佳.

基于Massflow模型的冷渍沟泥石流工程治理效果评价

强震影响区、充沛的雨量、特殊的地质环境使得西昌市冕宁县区域地质灾害频发。现场调查冕宁县冷渍沟泥石流,获取了泥石流的降雨雨量及泥石流密度等模拟的相关数据,利用Massflow和ArcGis软件,再现了冷渍沟泥石流的运动特征,得到泥石流工程治理前、后的危险性评价图。对比工程治理前后模拟图得出:工程治理前,冷渍沟泥石流最大流速8.55 m/s,最大泥深7.5m,沟道高危险区占77%、中危险区占13%、低危险区占10%;工程治理后,拦挡坝位置泥深最大,沟道堆积物减少且沟道与安宁河交汇处的危险区范围变小,危险程度明显减弱。评价结果表明:冷渍沟泥石流拦挡坝能很好地对泥石流冲出物进行拦截,从而达到降低沟域危险程度的工程治理目标。

Performance of a subsurface-flow constructed wetland in Southern China

The operational performance of a full scale subsurface flow constructed wetland, which treated the mixed industrial and domestic wastewater with BOD 5/COD mean ratio of 0 33 at Shatian, Shenzhen City was studied. The constructed wetland system consists of screens, sump, pumping station, and primary settling basin, facultative pond, first stage wetland and secondary stage wetland. The designed treatment capacity is 5000 m 3/d, and the actual influent flow is in the range of <2000 to >10000 m 3/d. Under normal operational conditions, the final effluent quality well met the National Integrated Wastewater Discharge Standard(GB 8978\_1996), with the following parameters(mean values): COD 33 90 mg/L, BOD 5 7.65 mg/L, TSS 7.92 mg/L, TN 9.11 mg/L and TP 0 56 mg/L. Seven species of plants were selected to grow in the wetland: Reed, Sweetcane flower Silvergrass, Great Bulrush, Powdery Thalia and Canna of three colours. The growing season is a whole year round. The seasonal discrepancy could be observed and the plants growing in the wetland are vulnerable to lower temperature in winter. The recycling of the effluent in the first stage of the wetland system is an effective measure to improve the performance of the wetland system. The insufficient DO value in the wetland system not only had significant effect on pollutants removal in the wetland, but also was unfavourable to plant growth. The recycling of effluent to the inlet of wetland system and artificial pond to increase DO value of influent to the wetland is key to operate the subsurface constructed wetland steadily and effectively.

Flow-Optimization to Enhance Gas Quenching Efficiency for Helical Gears Specimen

Numerical simulations based on a conjugate heat transfer solver have been carried out to analyze various gas quenching configurations involving a helical gear streamed by an air flow at atmospheric pressure in a gas quenching chamber. In order to optimize the heat transfer coefficient distribution at key positions on the specimen, configurations involving layers of gears and flow ducts comprising single to multiple gears have been simulated and compared to standard batch configurations in gas quenching. Measurements have been performed covering the local heat transfer for single gears and batch of gears. The homogeneity of the heat transfer coefficient is improved when setting up a minimal distance between the gears (batch density) and when introducing flow ducts increasing the blocking grade around the gears. An offset between layers of the batch as well as flow channels around the gears plays a significant role in increasing the intensity and the homogeneity of the heat transfer in gas quenching process.

Periodic flow characteristics during RH vacuum circulation refining

The circulation period of RH vacuum refining was studied to promote the refining efficiency. The influences of the lift gas flow rate and submersion depth of snorkels on the circulation period, and the relationship between mixing time and circulation flow were dis- cussed. The effects of the lift gas flow rate and submersion depth on the degassing rate in one circulation period were studied by water modeling. The results show that the circulation period is shortened by increasing the lift gas flow rate. The circulation period is the shortest when the submersion depth of snorkels is 560 mm. The whole ladle can be mixed thoroughly after three times of circulation. Increasing the lift gas flow rate can enhance the degassing rate of RH circulation.

Influence of Clip Locations on Intraaneurysmal Flow Dynamics in Patient-specific Anterior Communicating Aneurysm Models with Different Aneurysmal Angle

To improve aneurysm treatment,this study examined the influence of clip locations on hemodynamic factors in patient-specific anterior communicating artery(ACoA)aneurysms with different aneurysmal angle.We proposed a simplified classification of ACoA aneurysms using aneurysmal angle,defined by the angle of pivot of the aneurysmal dome and the virtual two-dimensional plane created by both proximal A2 segments of anterior cerebral artery(ACA).ACoA aneurysms with three different aneurysmal angles,which are 15°,80°and 120°,were analyzed in our study.In this work,we obtained hemodynamics before and after clipping surgery with three clip locations based on clinical clipping strategies in three ACoA aneurysms with different aneurysm angles.Results showed that local high pressure occurs at impingement region of the ACoA aneurysm before clipping and new impingement region close to the clipping location after clipping treatment.For clipping the aneurysm with aneurysmal angle 15°and a wide neck,wall shear stress(WSS)distribution is more uniform when the clipping angle of two clips close to 180°comparing with other two angles.In addition,for clipping the aneurysm with aneurysmal angle 80°and 120°,local high pressure appears on new impingement region and high WSS distributes around the clipping location when the clip plane is normal to the direction of inflow of aneurysm from the dominance of A1 segment of ACA.Hence,we should avoid the impingement of inflow from the A1 segment and choose a favorable clipping location for the fastness of clip.The results of our study could preoperatively give a useful information to the decision of surgical plan.

Flocculation Efficiency in Taylor-Couette Flow

Velocity field data were acquired for Taylor-Couette flow in the annulus gap between a rotating inner cylinder and a fixed concentric outer cylinder by particle image velocimetry. The flocculation efficiencies were also obtained in the same Taylor-Couette flow under the conditions corresponding to the velocity field measurement. It was shown that the flocculation efficiencies reach the maximum values due to the closed vortices in WVF and their contraction and expansion with time, but out of WVF range, the comparatively low flocculation efficiencies were obtained due to the no-closed vortices connected with each other.

iRoot SP、GuttaFlow2、AH Plus根管封闭剂的临床应用比较

目的对两种常温流动根充封闭剂(硅酸钙基-iRoot SP、硅氧烷基-GuttaFlow2)结合单尖充填技术以及常用封闭剂(AH Plus)结合连续波热牙胶充填技术的短期临床效果进行评价。方法将279颗患牙(656个根管)随机分为3组,分别为iRoot SP组、GuttaFlow2组以及AH Plus组。记录每个根管的充填时间,拍数字化牙片评估每个根管的充填效果,并于术后1周及1月进行回访,记录患者的疼痛发生率。SPSS18.0对以上数据行统计学分析。结果3组的根管充填效果均无统计学差异(P>0.05);iRoot SP组与GuttaFlow2组的充填时间无显著差异(P>0.05),较AH Plus组明显缩短(P<0.05);iRoot SP组与GuttaFlow2组的术后疼痛无统计学差异(P>0.05),iRoot SP组与GuttaFlow2组均较AH Plus组疼痛发生率较低(P<0.05)。结论GuttaFlow2和iRoot SP配合单尖充填技术较常用热牙胶充填技术节省填充时间,且能获得良好的临床效果,术后疼痛发生率较低。

BEHAVIOR OF FLOW STRESS OF ALUMINUM SHEETS USED FOR PRESSURE CAN DURING COMPRESSION AT ELEVATED TEMPERATURE

The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynamic hot-simulation testing machine. The results show that the AI sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s^-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the AI pieces prepared by no or conventional melt-treatment, hot deformation activation energy of AI sheets prepared by high-efficient melt-treatment is the smallest （ Q= 168.0kJ/mol）, which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.