Effect of surfactant frequently used in soil flushing on oxygen mass transfer in micro-nano-bubble aeration system

In-site soil flushing and aeration are the typical synergetic remediation technology for contaminated sites.The surfactant present in flushing solutions is bound to affect the aeration efficiency.The purpose of this study is to evaluate the effect of surfactant frequently used in soil flushing on the oxygen mass transfer in micro-nano-bubble(MNB)aeration system.Firstly,bio-surfactants and chemical surfactants were used to investigate their effects on Sauter mean diameter of bubble(dBS),gas holdup(ε),volumetric mass-transfer coefficient(kLa)and liquid-side mass-transfer coefficient(kL)in the MNB aeration system.Then,based upon the experimental results,the Sardeing's and Frossling's models were modified to describe the effect of surfactant on kL in the MNB aeration.The results showed that,for the twenty aqueous surfactant solutions,with the increase in surfactant concentration,the value of dBS,kLa and kL decreased,while the value ofεand gas-liquid interfacial area(a)increased.These phenomena were mainly attributed to the synergistic effects of immobile bubble surface and the suppression of coalescence in the surfactant solutions.In addition,with the presence of electric charge,MNBs in anionic surfactant solutions were smaller and higher in number than in non-ionic surfactant solutions.Furthermore,the accumulation of surfactant on the gas-liquid interface was more conspicuous for small MNB,so the reduction of kL in anionic surfactant solutions was larger than that in non-ionic surfactant solutions.Besides,the modified Frossling's model predicted the effect of surfactant on kL in MNB aeration system with reasonable accuracy.

Analysis and Prospect of Waste Heat Utilization from Blast Furnace Slag Flushing

Estimating the residual heat of blast furnace slag flushing in China,classifying and introducing the current proposed methods of slag flushing waste heat utilization,and listing existing cases.In order to better save energy and water in the slag flushing process of blast furnaces,an ideal comprehensive cascade utilization system scheme for annual recovery of waste heat is proposed.Based on the measured waste heat data of a steel plant,design calculations are carried out to further analyze the economic feasibility of the new scheme and provide reference for its promotion and application.

Stress-unloading and gas migration improvement mechanism in the soft and hard interbedded coal seam using directional hydraulic flushing technology

To enhance gas drainage in the soft and hard interbedded(SHI)coal seam,it’s necessary to unload the insitu stress and improve its gas migration performance.In this research,a directional hydraulic flushing(DHF)technology was carried out.The stress-unloading and gas migration improvement mechanism was analyzed through numerical simulation,and systematic engineering tests were conducted to verify the gas drainage effect.The results show that the improvement of gas migration performance in the SHI coal seam is caused by a combined effect of seepage-improving and diffusion-improving.After DHF,stress-unloading and plastic failure could be achieved both in the soft coal(SC)sublayer and in the hard coal(HC)sublayer.However,the gas diffusion capacity improves significantly in the SC sublayer,while the gas seepage capacity improves notably in the HC sublayer.Meanwhile,the stress-unloading and gas migration improvement effect improves with the flushing radius and the thickness of the SC sublayer.Besides,after adopting the DHF technology,the gas drainage effect improved markedly.The borehole number dropped by 49%,the gas drainage ratio increased from 26.0%to 48.2%,and the average coal roadway excavation speed increased from 2.4 to 5.6 m/d.

Vancomycin flushing syndrome in orthopaedic practice:A case report

BACKGROUND Vancomycin flushing syndrome(VFS),also known as red man syndrome,is an allergic reaction to vancomycin.It typically presents as a rash on the face,neck,and upper torso after intravenous administration of vancomycin.VFS is blamed on rapid intravenous infusion of vancomycin during management and rarely happens after local use.A review of the literature showed that in the last 23 years,4 such cases have been reported.Here,we add another case of VFS developed after slow local absorption of vancomycin in cement beads.CASE SUMMARY A 44-year-old male with a known case of hypertension,no history of allergies to medications,and a history of chronic osteomyelitis of the right tibia with discharging sinus over the anterolateral aspect of the leg.The pus culture grew Staphylococcus aureus,which was sensitive to clindamycin and vancomycin.The patient underwent irrigation and debridement with the placement of vancomycin cement beads made from 4 g of vancomycin powder and 40 g of polymethyl methacrylate.Three hours postoperatively,the patient developed a pruritic,erythematous,macular rash predominantly on his face,neck,chest,and lower extremities and to a lesser extent his upper extremities.A diagnosis of VFS was made and was successfully treated with cetirizine(10 mg,oral)and methylprednisolone sodium succinate(125 mg,intravenous).The patient continued to have itching with a facial rash for 12 h with gradual improvement.A decision was made to not remove the beads as the patient continued to improve.Gradually,the rash disappeared after 96 h with no further sequela.CONCLUSION VFS can occur not only after rapid intravenous injection of vancomycin but also with local release,as in our case.As orthopaedic surgeons routinely use vancomycin with polymethyl methacrylate in chronic osteomyelitis and revision arthroplasty,they should be aware of such a complication occurring.

Flush by Unit在哥伦比亚Capella油田的应用

Capella油田是哥伦比亚南部重要的稠油油田,目前处于开发生产阶段,为了油田的稳产增产,需频繁对油井进行干预。Flush by Unit具有操作简单、移动高效、作业时间缩短、安全事故少等优点,作为试点引入了Flush by Unit为该油田的浅井提供修井服务,以降低桶油成本。本文介绍了Flush by Unit的结构组成、使用范围、现场使用效果,与传统修井机相比,可以大幅降低作业时间和成本,为后续规模使用Flush by Unit进行常规修井提供了依据,也为油田的增产稳产带来了机遇。

Design and Fluid-Dynamic Analysis of a Flushing Nozzle for Drilling Applications

The actuator is a key component of the creaming tool in drilling applications.Its jet performances determine the effective reaming efficiency.In this work,a new selective reaming tool is proposed and the RNG k-εturbulence model is used to calculate its internal and externalflowfields.In particular,special attention is paid to the design of theflushing nozzle.The results show that the jet originating from theflushing nozzle has a significant influence on rock cutting and blade cooling effects.In turn,the jet performances depend on geometric structure of the creaming actuator.In this framework,a conical-cylindrical nozzle with a diameter of 7 mm is initially considered as a basis to implement a strategy to optimize the structural parameters of the reaming actuator,and improve the related side tracking reconstruction technology.

基于flushing time的春季水库优化调度可行性研究

针对三峡水库支流库湾春季水华问题,通过建立三维水动力模型,探讨了利用调峰调度和潮汐式调度促进干支流水体交换的可行性。研究表明,当4月水库实施调峰调度时,整个库湾水体的flushing time较常规调度有所缩短,尤其是库湾上游至中上游区域;当5月水库开始实施潮汐式调度时,水体体积较大的库湾下游区域的flushing time较常规调度方案有所缩短。可见,两种水库优化调度方案对增大干支流水体交换均具有可行性。当水库实施调峰调度和潮汐式调度联合调度时,整个库湾水体的平均flushing time较常规调度方案有不同程度的缩短,表明该联合调度方案更能促进干支流水体的交换。研究成果可为支流库湾水环境问题的防治提供借鉴。

Flush刀和SB刀在经口内镜下肌切开术治疗贲门失弛缓症中的临床应用

背景:经口内镜下肌切开术(POEM)目前已被广泛用于治疗贲门失弛缓症(AC)且效果显著。然而,POEM手术操作难度大,术后并发症发生率高。目的:探讨Flush刀和SB刀在POEM治疗AC中的有效性和安全性。方法:选取2013年4月—2017年4月武汉大学人民医院确诊为AC且接受POEM治疗的111例患者,将其分为Flush刀组、SB刀组和Dual刀组。比较三组手术相关指标、并发症和术后随访等方面的差异。结果:111例AC患者均顺利完成了POEM,三组平均手术时间、平均止血次数和平均更换设备的次数相比差异有统计学意义(P均<0.05),进一步两两比较显示,Flush刀组和SB刀组上述手术相关指标均明显低于Dual刀组(P均<0.05)。三组术后并发症发生率相比差异有统计学意义(P=0.005),进一步两两比较显示,SB刀组显著低于Dual刀组(P=0.011),而Flush刀组与Dual刀组无明显差异(P=0.056)。三组手术治疗成功率无明显差异(P>0.05)。结论:Flush刀和SB刀能有效缩短POEM治疗AC的手术时间,且其成功率与常规Dual刀相似。

flush_action重选参数设置对数据业务用户感知的影响分析与设置优化

日常网络优化过程中往往只着重对语音无线参数进行调整优化,但随着数据业务突飞猛进的发展,GPRS承载网中同样存在设备参数的调整和优化问题。大家都知道在语音业务中用户从原来的小区进入到新的小区要进行切换,而数据业务中不存在切换流程,只有对应的小区重选,小区重选参数设置不合理会直接影响数据业务传输速率甚至会导致传输过程失败,从而对用户感知度产生较大影响,因此,合理优化小区重选参数就显得尤为重要,本文主要要对flush-ll-ack消息参数action设置不同对网络时延造成的不同影响进行论述分析,从而通过该参数调整优化来进一步提升数据业务网络质量,提升用户感知度。

First flush of storm runoff pollution from an urban catchment in China

Storm runoff pollution process was investigated in an urban catchment with an area of 1.3 km^2 in Wuhan City of China. The results indicate that the pollutant concentration peaks preceded the flow peaks in all of 8 monitored storm events. The intervals between pollution peak and flow peak were shorter in the rain events with higher intensity in the initial period than those with lower intensity. The fractions of pollution load transported by the first 30% of runoff volume （FF30） were 52.2%-72.1% for total suspended solids （TSS）, 53.0%-65.3% for chemical oxygen demand （COD）, 40.4%-50.6% for total nitrogen （TN）, and 45.8%-63.2% for total phosphorus （TP）, respectively. Runoff pollution was positively related to non-raining days before the rainfall. Intercepting the first 30% of runoff volume can remove 62.4% of TSS load, 59.4% of COD load, 46.8% of TN load, and 54.1% of TP load, respectively, according to all the storm events. It is suggested that controlling the first flush is a critical measure in reduction of urban stormwater pollution.

A retrospective observational study on maintenance and complications of totally implantable venous access ports in 563 patients:Prolonged versus short flushing intervals

Objectives:To assess whether the extension of the flushing interval will increase risks of complications associated with totally implantable venous access port(TIVAP)in the off-treatment period.Methods:A retrospective single-center observational study was performed.Patients with a TIVAP in the off-treatment period that underwent regular flushing in our clinic were included.Data concerning patients and their TIVAPs were recorded.Patient baseline characteristics and TIVAP-related complications were analyzed.Continuous variables were analyzed by ANOVA or the Kruskal-Wallis H test.To compare the occurrence of TIVAP-related complications,the chi-square test was used;if needed,Fisher’s exact test was used.Results:Totally 607 patients were reviewed,and 563 patients were finally included.Thirteen complications were recorded,including 11 cases of catheter occlusion(1.95%),one case of port cannula rotation(0.18%),and one case of catheter tip malposition(0.18%).No device-related infection or venous thrombosis was recorded.Among these patients,the average flushing interval was 35.27±13.09 days.Patients were divided into three groups according to the flushing interval:every 28 days or less(Group 1,n=133);every 29-44 days(Group 2,n=350);and every 45 days or more(Group 3,n=80).No significant difference in catheter-related complications was found among the three groups(P>0.05).Conclusions:In the TIVAP off-treatment period,patients without any history of TIVAP-related complications during approximately one year can attempt to prolong the flushing interval to more than 4 weeks;we further suggest that 5-6 weeks may be an appropriate option for these patients.

Flush Pin检具的检测方法研究

介绍了Flush Pin检具的外形特点及特殊的检测要求,设计制造专用夹具及检测装置对其进行检测,并总结归纳了相关的检测方法以及方法的选择原则。

Improved Algorithms for Flush Airdata Sensing System

The Flush Airdata Sensing （FADS） system and its pressure model are presented briefly. The improved algorithm for calculating the impact pressure, static pressure and modifying coefficient are studied. First, the non-linear equations are simplified using Moore-Penrose inverse. Then the impact pressure and static pressure are computed with the improved iteration and BP neural network. Both the two improved algorithms meet the requirements of the flush airdata sensing system on precision, reliability and speed. BP neural network has great advantages on real-time requirements, for it needs only 5% time to reach the required precision comparing to the original algorithm.

基于Flush+Reload的DES算法Cache计时攻击

在数据加密标准(DES)算法上使用Flush+Reload方法的Cache计时攻击,存在难以确定S盒元素行偏移位的问题。为此,利用S盒在Cache中会发生不对齐分布的特征,提出一种偏移位确定方法。采用clflush指令刷新Cache地址行,以驱逐Cache中DES算法的S盒信息,确定S盒元素的位置信息。利用密码算法在查询S盒时泄露的Cache计时信息获取明文与密钥异或后的中间态值,并通过该值和已知明文的相关性恢复密钥。实验结果表明,该方法能够有效确定S盒元素的行偏移位,提高针对DES算法Cache计时攻击的效率。

Tidal Flushing Time of Marine Fish Culture Zones in Hong Kong

Accurate determination of flushing time is crucial for maintaining sustainable production in fish culture zones （FCZs）, as it represents the physical self-purification capability via tidal exchange with clean water in the outer sea. However, owing to the temporal and spatial complexity of the coastal flushing process, existing methods for determining flushing time may not be generally applicable. In this paper, a systematic method for determining the flushing time in FCZs is presented, in which bathymetry, runoff, tidal range and stratification are properly accounted for. We determine the flushing time via numerical tracer experiments, using robust 3D hydrodynamic and mass transport models. For FCZs located in sheltered and land-locked tidal inlets, the system boundary can be naturally defined at the connection with the open sea. For FCZs located in open＇waters, hydrodynamic tracking is first used to assess the extent of tidal excursion and thus delimit the initial boundary between clean water and polluted water. This general method is applied to all designated marine FCZs in Hong Kong for both the dry and wet seasons, including 20 sheltered FCZs （in semi-enclosed waters of Tolo Harbour, Mirs Bay, and Port Shelter） and 6 FCZs in open waters. Our results show that flushing time is the longest in inner Port Shelter （about 40 days in dry season）, and the shortest for the FCZs in open waters （less than one week in dry season）. In addition, the flushing time in dry season is commonly longer than that in wet season： 20%~40% for most well-sheltered FCZs; 2.6-4 times for the others. Our results indicate a positive correlation between the flushing time and distance to open boundary, supporting the view that the flushing time of a FCZ is closely related to its location. This study provides a solid basis for mariculture management such as the determination of carrying capacity of FCZs.

Sustainable Application of a Novel Water Cycle Using Seawater for Toilet Flushing

Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater could serve as a freshwater supply. However, since 20%-30% of the water supply is used for flushing waste from the city, seawater with simple treatment could also partly replace the use of freshwater. In this work, the freshwater saving potential and environmental impacts of the urban water system （water-wastewater closed loop） adopting seawater desalination, seawater for toilet flushing （SWTF）, or reclaimed water for toilet flushing （RWTF） are compared with those of a conventional freshwater system, through a life-cycle assessment and sensitivity analysis. The potential applications of these processes are also assessed. The results support the environmental sustainability of the SWTF approach, but its potential application depends on the coastal distance and effective population density of a city. Developed coastal cities with an effective population density exceeding 3000 persons.km-2 and located less than 30 km from the seashore （for the main pipe supplying seawater to the city） would benefit from applying SWTF, regardless of other impact parameters. By further applying the sulfate reduction, autotrophic denitrification, and nitrification integrated （SANI） process for wastewater treatment, the maximum distance from the seashore can be extended to 60 km. Considering that most modern urbanized cities fulfill these criteria, the next generation of water supply systems could consist of a freshwater supply coupled with a seawater supply for sustainable urban development.

Effect of drip irrigation method, nitrogen source, and flushing schedule on emitter clogging

Field experiments were carried out at the National Research Center farm, Nubaria area, Behura Governorate, Egypt, to study the effect of nitrogen source, flushing schedule and irrigation method on emitter clogging. Peanut Giza 5 variety (Arachishy pogaea L.) was planted in sandy soil during two successive growing seasons (2010-2011) in the 1st week of May and harvested after 130 days. Treatments used are: 1) two irrigation methods: surface drip irrigation and sub-surface drip irrigation (SDI;SSDI), 2) nitrogen source (NS):NH4NO3, (NH4)2SO4 and Ca(NO3)2 (NS1, NS2 and NS3) and 3) flushing number (FL) 0, 1 and 4 (FL1, FL2;FL3). The experiments design was split-split plot and three replicates were used. Data obtained were subjected to statistical analysis. The main effects of treatments used on clogging per cent could be written the following ascending orders: SDI 3 2 1, NS1 2 3. Concerning the 1st interaction the following ascending orders denote their effects on clogging percent: SDI × FL3 2 1, SDI × NS1 2 3, SSDI × FL3 2 1, SSDI × NS1 2 3, FL1 × NS1 1 × NS2 1 × NS3, FL2 × NS1 2 × NS2 2 × NS3 and FL3 × NS1 3 × NS2 3 × NS3. The differences between any two treatments and/or any two interactions in clogging percent were significant at the 5% level. The effect of the 2nd interaction on clogging percent was significant at the 5% level. The maximum value of clogging (20.18%) and the lowest one (3.9%) were archived in the interactions: SSDI × FL1 × NS3 and SDI × FL3 × NS1, respectively.

Characterization of suspended solids and particle-bound heavy metals in a first flush of highway runoff

To investigate the dynamic characteristics of total suspended solids (TSS) and their particle-bound heavy metals in a first flush, the runoff sampling together with its flow rate measuring was conducted for three rainfall events at outfalls of highway in Shanghai from June to September 2007. Field samples were analyzed to determine the concentrations of TSS and particle-bound heavy metals, such as Zn, Pb, and Cu. Results show that the wash off behavior of TSS under varying runoff rate condition can be explained by different antecedent dry weather period (ADWP). Contribution of fine fraction (<45 μm) to TSS was generally higher than that of coarse fraction (>45 μm). When the runoff flow increased obviously, a significant contribution of the coarse fraction was observed for a certain rainfall events with long antecedent dry weather condition. The changes of total metals concentration and particle-bound metal concentrations were strongly dependent on the TSS variation. TSS was generally well correlated with most particulate-bound heavy metals. Of the heavy metals, the concentration of Zn was found considerably high and that of Pb was significantly low at North Zhongshan 2 Road, in Shanghai, China, but they are still within the range reported in the literature. Fluctuation of heavy metal contents in the coarse fraction during a first flush period was more significant compared with that in the fine fraction. The results will assist in the development of effective control strategies to minimize heavy metals and solids in highway runoff.

Study on the Effects of FCu-IUD and FICu-IUD on Matrix metalloproteinases in Human Uterine Flushing and Endometrium

The activity of matrix metalloproteinases (MMPs) in the uterine flushing and endometrial tissue of normal adult women wearing FCu IUD (fixed Cu IUD) or FICu IUD (indomethacin releasing FCu IUD) was observed by using zymography on SDS PAGE containing gelatin. The results showed that the activity and kinds of MMPs in FCu IUD group were increased significantly as compared with themselves before being inserted FCu IUD. However, compared with the FCu IUD group, the activity of some kinds of MMPs in the FICu IUD group was decreased significantly. These data suggest that IUD can enhance the activity of MMPs in human endometrium, intermediated by prostaglandins, and MMPs may have relation to IUD induced menorrhagia and indomethacin reduces IUD induced menorrhagia by partly inhibiting MMPs synthesis.

Enhancing diamond drilling performance by the addition of non-ionic polymer to the flushing media

Drilling is a most important and crucial operation in the excavation industries.With the objective of looking into the enhancement of diamond drilling performance detailed laboratory investigations were carried out on phosphate rock.The effect of Poly（Ethylene Oxide）（PEO） added to the drilling water was studied by varying machine parameters and PEO concentration.The responses were rate of penetration and torque at the bit rock interface.Slake durability tests were also performed to understand the slaking behavior of phosphate rock in PEO solutions.