Impact of the Inlet Flow Angle and Outlet Placement on the Indoor Air Quality

This study aims to optimize the influence of the inlet inclination angle on the Indoor Air Quality(IAQ),heat,and temperature distribution in mixed convection within a two-dimensional square cavityfilled with an air-CO_(2)mixture.The air-CO_(2)mixture enters the cavity through two inlet openings positioned at the top wall,which is set at the ambient temperature(TC).Three values of the Reynolds numbers,ranging from 1000 to 2000,are considered,while the Prandtl number is kept constant(Pr=0.71).The temperature distribution and streamlines are shown for Rayleigh number(Ra)equal to 104,three inlet inclination anglesϕ(0,π/6 andπ/4)and three CO_(2)concentrations values(1500,2500,3500 ppm)applied at both hot vertical walls(maintained at a constant temperature TH).Afinite volume method is used under the assumption of two-dimensional laminarflow to solve the NavierStokes and energy equations.The results indicate that inlet inclination angle has an impact on the indoor air quality(IAQ),which,in turn,affects the heat transfer distribution and thermal comfort within the cavity.

Primary gastroduodenal tuberculosis presenting as gastric outlet obstruction:A case report and review of literature

BACKGROUND Mycobacterium tuberculosis(TB)is the causative agent of TB,a chronic granulo-matous illness.This disease is prevalent in low-income countries,posing a significant global health challenge.Gastrointestinal TB is one of the three forms.The disease can mimic other intra-abdominal conditions,leading to delayed diagnosis owing to the absence of specific symptoms.While gastric outlet obs-truction(GOO)remains a frequent complication,its incidence has declined with the advent of proton pump inhibitors and Helicobacter pylori eradication therapy.Gastroduodenal TB can cause upper gastrointestinal hemorrhage,obstruction,and malignancy-like tumors.CASE SUMMARY A 23-year-old male presented with recurrent epigastric pain,distension,nausea,vomiting,and weight loss,prompting a referral to a gastroenterologist clinic.Endoscopic examination revealed distorted gastric mucosa and signs of chronic inflammation.However,treatment was interrupted,possibly owing to vomiting or comorbidities such as human immunodeficiency virus infection or diabetes.Subsequent surgical intervention revealed a dilated stomach and diffuse thickening of the duodenal wall.Resection revealed gastric wall effacement with TB.CONCLUSION Primary gastric TB is rare,frequently leading to GOO.Given its rarity,suspicions should be promptly raised when encountering relevant symptoms,often requiring surgical intervention for diagnosis and treatment.

Numerical simulation of inlet placement on sewage characteristics in the rounded square aquaculture tank with single inlet

To improve the self-cleaning ability of aquaculture tank and the efficiency of circulating water,physical and numerical experiments were conducted on the influence of inlet structure on sewage discharge in a rounded square aquaculture tank with a single inlet.Based on the physical model of the tank,analysis of how inlet structure adjustment affects sewage discharge efficiency and flow field characteristics was conducted to provide suitable flow field conditions for sinkable solid particle discharge.In addition,an internal flow field simulation was conducted using the RNG k-εturbulence model in hydraulic drive mode.Then a solid-fluid multiphase model was created to investigate how the inlet structure affects sewage collection in the rounded square aquaculture tank with single inlet and outlet.The finding revealed that the impact of inlet structure is considerably affecting sewage collection.The conditions of C/B=0.07-0.11(the ratio of horizontal distance between the center of the inlet pipe and the tank wall(C)to length of the tank(B))andα=25°(αis the angle between the direction of the jet and the tangential direction of the arc angle)resulted in optimal sewage collection,which is similar to the flow field experiment in the rounded square aquaculture tank with single inlet and outlet.An excellent correlation was revealed between sewage collection and fluid circulation stability in the aquaculture tank.The present study provided a reference for design and optimization of circulating aquaculture tanks in aquaculture industry.

Navigating Market Choices: Understanding Carrot Market Outlet Selection among Smallholder Farmers in Kenya

This research delves into the hurdles and strategies aimed at augmenting the market involvement of smallholder carrot farmers in Nakuru County, Kenya. Employing a Multinomial Logit (MNL) model, it scrutinizes the factors influencing the selection of marketing outlets among carrot farmers. The findings unveil that a significant majority (81%) of surveyed farmers actively participate in diverse market outlets, encompassing the farm gate, cleaning point, local market, external market, and export market. Notably, pivotal buyers include aggregators, brokers, wholesalers, retailers, and consumers, with transactions predominantly occurring at the farm level. Additionally, the analysis discerns substantial influences of socio-economic characteristics, experiential factors, and geographical proximity on farmers’ choices of market outlets. Specifically, gender, age, land size, farming experience, and distance to markets emerge as critical determinants. Moreover, the study delves into the examination of market margins along the carrot value chain, shedding light on the potential profitability of carrot farming in the region. Remarkably, higher average gross margins are identified in export and external markets, signaling lucrative prospects for farmers targeting these segments. However, disparities in profit distribution between farmers and traders underscore the necessity for interventions to ensure equitable value distribution throughout the value chain. These findings underscore the imperative for tailored interventions to tackle challenges and foster inclusive agricultural development. Strategies such as farmer organizations, contracting, and vertical integration are advocated to enhance market access and profitability for smallholder carrot farmers. Thus, this study enriches our comprehension of the dynamics within carrot value chains and provides valuable insights for policymakers and development practitioners aiming to uplift rural livelihoods and bolster food security.

Aerodynamic/stealth design of S-duct inlet based on discrete adjoint method

It is a major challenge for the airframe-inlet design of modern combat aircrafts,as the flow and electromagnetic wave propagation in the inlet of stealth aircraft are very complex.In this study,an aerodynamic/stealth optimization design method for an S-duct inlet is proposed.The upwind scheme is introduced to the aerodynamic adjoint equation to resolve the shock wave and flow separation.The multilevel fast multipole algorithm(MLFMA)is utilized for the stealth adjoint equation.A dorsal S-duct inlet of flying wing layout is optimized to improve the aerodynamic and stealth characteristics.Both the aerodynamic and stealth characteristics of the inlet are effectively improved.Finally,the optimization results are analyzed,and it shows that the main contradiction between aerodynamic characteristics and stealth characteristics is the centerline and crosssectional area.The S-duct is smoothed,and the cross-sectional area is increased to improve the aerodynamic characteristics,while it is completely opposite for the stealth design.The radar cross section(RCS)is reduced by phase cancelation for low frequency conditions.The method is suitable for the aerodynamic/stealth design of the aircraft airframe-inlet system.

Revisiting tuberculosis as a cause of gastric outlet obstruction:Insights from a case report

Gastroduodenal tuberculosis(GD-TB)is exceptionally rare.The clinical manifestations of gastrointestinal TB are diverse and non-specific,which makes diagnosis difficult,leading to delayed diagnosis and high mortality.As a peer-reviewer of World Journal of Clinical Cases,I would like to share my opinion on the article published by this journal.The patient had no family history of TB or contact with people with TB.Primary GD-TB presenting as gastric outlet obstruction and normal findings of thoracic computed tomography increased the difficulty of diagnosis and treatment in this patient.The diagnosis and treatment scheme of this typical case have reference value for the clinical treatment of GD-TB.

Unveiling hidden outcomes in malignant gastric outlet obstruction research–insights from a"Pancreas 2000"review

Malignant gastric outlet obstruction(mGOO)is a major condition affecting patients with periampullary tumors,including pancreatic cancer.The current treatment options include surgical gastroenterostomy,endoscopic stenting and more recently EUS-guided gastroenterostomy.Most studies comparing the outcomes of the three procedures focus on technical success,clinical success and safety.Several“occult”outcomes relevant to the patient’s viewpoints and perspective may ultimately impact on cancer-related and overall survival,such as body mass composition,nutritional biomarkers,chemotherapy tolerance and patient-reported quality of life.The aim of this review is to provide an overview of potential key outcomes that should be explored in future comparative research around mGOO treatment options.

Treatment of choice for malignant gastric outlet obstruction: More than clearing the road

In this editorial,we comment on the in-press article in the World Journal of Gas-trointestinal Endoscopy concerning the treatment of malignant gastric outlet obstruction(mGOO).The original theory of treatment involves bypassing the obstruction or reenabling the patency of the passage.Conventional surgical gastroenterostomy provides long-term relief of symptoms in selected patients,with substantial morbidity and a considerable rate of delayed gastric emptying.Endoscopic stenting was introduced as an alternative minimally invasive proce-dure with less procedural morbidity and rapid clinical improvement;however,it presented a high rate of long-term recurrence.Therefore,challenges remain in the treatment of mGOO patients to improve clinical outcomes.Endoscopic ultra-sound-guided gastroenterostomy has recently emerged as a promising method because of the combined effects of surgery and endoscopy,whereas stomach-partitioning gastrojejunostomy has been reported as a modified surgical proce-dure to reduce the rate of delayed gastric emptying.In decision-making regarding the treatment of choice,it should be taken into account that mGOO might be accompanied by a variety of pathological conditions,including cancer cachexia,anorexia,malabsorption,and etc.,all of which can also lead to the characteristic symptoms and poor nutritional status of mGOO.The treatment plan should consider comprehensive aspects of patients to achieve practical improve-ments in prognosis and the quality of life.

Endoscopic ultrasound-guided gastroenterostomy for gastric outlet obstruction in Mexico

BACKGROUND Endoscopic ultrasound-guided gastroenterostomy(EUS-GE)has recently emerged as an alternative treatment for gastric outlet obstruction(GOO)in selected patients.AIM To report the initial experience of EUS-GE in patients with GOO.METHODS This study was a retrospective,observational,multicenter study in which the data from 10 patients who underwent EUS-GE due to GOO between September 2021 and May 2023 were collected.We analyzed technical success,clinical success,adverse events,and survival.Technical success was defined as adequate positioning and deployment of the stent.Clinical success was defined as the patient’s ability to tolerate oral intake without vomiting 7 d after the procedure.Postprocedural adverse events were recorded.RESULTS Eleven procedures in 10 patients with GOO were included.The mean age of the patients was 67.5 years(range:56-77 years).Malignant GOO was present in 9 patients.Technical success was achieved in 9/11 procedures(82%).Among them,clinical success was achieved in 9 patients(100%).Adverse events occurred in 1 patient(9%).The median survival was 3 months(n=7;range:1-8 months).CONCLUSION EUS-GE is a feasible therapeutic option in the treatment of GOO.

NUMERICAL SIMULATIONS OF THE HYDRAULIC CHARACTERISTICS OF SIDE INLET/OUTLETS

The hydraulic characteristics at the side inlet/outlet of pumped storage plants is studied by numerical simulations,covering the flow distribution,head loss,vortex,and others.Based on the physical model test,the realizable k-εturbulence model is used in the 3-D simulation of the side inlet/outlet.A new scheme is suggested to obtain the uneven flow distribution over three branch orifices.The variation of the free surface with the reservoir water level under the pumped condition is simulated,with results consistent with the experimental results.

Flow patterns and boundary conditions for inlet and outlet conduits of large pump system with low head

The flow patterns in the inlet and outlet conduits have a decisive effect on the safe, stable, and highly efficient operation of the pump in a large pumping station with low head. The numerical simulation of three-dimensional （3D） turbulence flow in conduits is an important method to study the hydraulic performance and conduct an optimum hydraulic design for the conduits. With the analyses of the flow patterns in the inlet and outlet conduits, the boundary conditions of the numerical simulation for them can be determined. The main obtained conclusions are as follows： （i） Under normal operation conditions, there is essentially no pre-swirl flow at the impeller chamber inlet of an axial-flow pump system, based on which the boundary condition at the inlet conduit may be defined. （ii） The circulation at the guide vane outlet of an axial-flow pump system has a great effect on the hydraulic performance of the outlet conduit, and there is optimum circulation for the performance. Therefore, it is strongly suggested to design the guide vane according to the optimum circulation. （iii） The residual circulation at the guide vane outlet needs to be considered for the inlet boundary condition of the outlet conduit, and the value of the circulation may be measured in a specially designed test model.

Numerical Investigation of the Aerodynamic Performance Affected by Spiral Inlet and Outlet in a Positive Displacement Blower

The flow in the positive displacement blower is very complex.The existing two-dimensional numerical simulation cannot provide the detailed flow information,especially flow characteristics along the axial direction,which is unfavorable to improve the performance of positive displacement blower.To investigate the effects of spiral inlet and outlet on the aerodynamic performance of positive displacement blower,three-dimensional unsteady flow characteristics in a three-lobe positive displacement blower with and without the spiral inlet and outlet are simulated by solving Navier-Stokes equations coupled with RNG k-ε turbulent model.In the numerical simulation,the dynamic mesh technique and overset mesh updating method are used.The computational results are compared with the experimental measurements on the variation of flow rate with the outlet pressure to verify the validity of the numerical method presented.The results show that the mass flow rate with the change of pressure is slightly affected by the application of spiral inlet and outlet,but the internal flow state is largely affected.In the exhaust region,the fluctuations of pressure,velocity and temperature as well as the average values of velocity are significantly reduced.This illustrates that the spiral outlet can effectively suppress the fluctuations of pressure,thus reducing reflux shock and energy dissipation.In the intake area,the average value of pressure,velocity and temperature are slightly declined,but the fluctuations of them are significantly reduced,indicating that the spiral inlet plays the role in making the flow more stable.The numerical results obtained reveal the three-dimensional flow characteristics of the positive displacement blower with spiral inlet and outlet,and provide useful reference to improve performance and empirical correction in the noise-reduction design of the positive displacement blowers.

Transoral outlet reduction:Outcomes of endoscopic Roux-en-Y gastric bypass revision in 284 patients at a community practice

BACKGROUND Transoral outlet reduction(TORe)is a minimally invasive endoscopic revision of Roux-en-Y gastric bypass(RYGB)for weight recurrence;however,little has been published on its clinical implementation in the community setting.AIM To characterize the safety and efficacy of TORe in the community setting for adults with weight recurrence after RYGB.METHODS This is a retrospective cohort study of argon plasma coagulation and purse-string suturing for gastric outlet reduction in consecutive adults with weight recurrence after RYGB at a single community center from September 2020 to September 2022.Patients were provided longitudinal nutritional support via virtual visits.The primary outcome was total body weight loss(TBWL)at twelve months from TORe.Secondary outcomes included TBWL at three months and six months;excess weight loss(EWL)at three,six,and twelve months;twelve-month TBWL by obesity class;predictors of twelve-month TBWL;rates of post-TORe stenosis;and serious adverse events(SAE).Outcomes were reported with descriptive statistics.RESULTS Two hundred eighty-four adults(91.9%female,age 51.3 years,body mass index 39.3 kg/m^(2))underwent TORe an average of 13.3 years after RYGB.Median pre-and post-TORe outlet diameter was 35 mm and 8 mm,respectively.TBWL was 11.7%±4.6%at three months,14.3%±6.3%at six months,and 17.3%±7.9%at twelve months.EWL was 38.4%±28.2%at three months,46.5%±35.4%at six months,and 53.5%±39.2%at twelve months.The number of follow-up visits attended was the strongest predictor of TBWL at twelve months(R^(2)=0.0139,P=0.0005).Outlet stenosis occurred in 11 patients(3.9%)and was successfully managed with endoscopic dilation.There was one instance of post-procedural nausea requiring overnight observation(SAE rate 0.4%).CONCLUSION When performed by an experienced endoscopist and combined with longitudinal nutritional support,purse-string TORe is safe and effective in the community setting for adults with weight recurrence after RYGB.

竖井式进出水口水力特性研究进展

竖井式进出水口是抽水蓄能电站水道系统两端控制水流的常用进出水口型式之一。竖井式进出水口双向过流,水流在短距离内经历两次90°流向转变(水平-竖直-水平),流向变化剧烈,水力条件复杂,深入研究竖井式进出水口水力特性,进而优化其体型结构,对抽水蓄能电站设计及施工具有重要意义。首先,介绍竖井式进出水口应用背景及体型特点,分析竖井式进出水口水力特性存在的问题;其次,对竖井式进出水口孔口流量分配、拦污栅断面流速分布、漩涡和水头损失等方面研究进展进行总结;最后,归纳了竖井式进出水口水力特性研究方法,探讨了今后研究应聚焦的主要方向。

Modified stomach-partitioning gastrojejunostomy for initially unresectable advanced gastric cancer with outlet obstruction: A case report

BACKGROUND Chemotherapy followed by gastrojejunostomy remains the main treatment for unresectable gastric cancer(GC)in the middle-or lower-third regions with gastric outlet obstruction(GOO).Radical surgery is performed as part of a multimodal treatment strategy for selected patients who respond well to chemotherapy.This study describes a case of successful radical resection with completely laparoscopic subtotal gastrectomy after a modified stomach-partitioning gastrojejunostomy(SPGJ)for obstruction relief,in a patient with GOO.CASE SUMMARY During the initial esophagogastroduodenoscopy,an advanced growth was detected in the lower part of the stomach,which caused an obstruction in the pyloric ring.Following this,a computed tomography(CT)scan revealed the presence of lymph node metastases and tumor invasion in the duodenum,but no evidence of distant metastasis was found.Consequently,we performed a modified SPGJ,a complete laparoscopic SPGJ combined with No.4sb lymph node dissection,for obstruction relief.Seven courses of adjuvant capecitabine plus oxaliplatin combined with Toripalimab(programmed death ligand-1 inhibitor)were administered thereafter.A preoperative CT showed partial response;therefore,completely laparoscopic radical subtotal gastrectomy with D2 lymphadenectomy was performed after conversion therapy,and pathological complete remission was achieved.CONCLUSION Laparoscopic SPGJ combined with No.4sb lymph node dissection was an effective surgical technique for initially unresectable GC with GOO.

侧式进/出水口各孔道流量分配差异及影响因素

对于抽水蓄能电站侧式进/出水口各孔道流量分配,现有设计规范规定进/出水口相邻中边孔道的流量不均匀程度不宜超过10%,但实际工程设计难以达到此要求.本文以某抽水蓄能电站侧式进/出水口为例,通过优化进/出水口各体型参数,利用数值模拟方法研究各孔道流量等水力参数,重点分析分流墩布置对各孔道流量分配的影响及其规律,试图使进流工况和出流工况相邻中边孔道的流量不均匀程度均最小.研究表明,改变扩散段分流墩布置能有效改善流量不均匀程度.对于3墩4孔侧式进/出水口,相邻中边孔道的流量不均匀程度在出流工况下随中边孔宽度比增大而增大,在进流工况下随中边孔宽度比增大而减小;当中边孔宽度比增大且中墩后移距离减小时,出流工况和进流工况下的流量不均匀程度均减小.对于2墩3孔侧式进/出水口,相邻中边孔道的流量不均匀程度不论在出流工况下还是在进流工况下,均随中边孔宽度比增大呈先减小后增大的规律.优化后的3墩4孔侧式进/出水口的中边孔宽度比取0.228∶0.272,中墩后移距离取0.36D(D为隧洞直径),其相邻中边孔道的流量不均匀程度均较优,在出流工况下为18.47%~19.43%,在进流工况下为19.82%~19.83%;优化后的2墩3孔侧式进/出水口的中边孔宽度比取0.310∶0.345,其相邻中边孔道的流量不均匀程度均较优,在出流工况下为19.47%~19.63%,在进流工况下为18.66%~18.67%.相邻中边孔道的流量不均匀程度较难满足不宜超过10%的设计规范要求.研究成果将有助于《抽水蓄能电站设计规范》中关于进/出水口水力指标要求的完善.

Outcomes of Transcatheter Closure in Outlet-Type Ventricular Septal Defect after 1 Year

Background:Ventricular septal defect(VSD)is the most common congenital heart disease.Transcatheter VSD closure is an effective treatment for patients with muscular and perimembranous VSD.However,there is a limit data for outlet VSD,especially impact to the aortic valve leaflet after transcatheter closure.This study aims to assess the outcomes of transcatheter closure of the outlet-type ventricular septal defect(OVSD)after 1 postoperative year.Methods:A retrospective study was performed including 50 patients who underwent transcatheter(n=25)and surgical(n=25)OVSD closure during the exact time frame at two medical centres.Results:The median age and body weight of patients in the transcatheter group were significantly higher than those of patients in the surgical group(7.0 vs.2.8 years;27.0 vs.11.4 kg;p<0.01).The defect size in the surgical group was significantly larger than that in the transcatheter group(5.0 vs.3.0 mm;p<0.01).All OVSD patients have successful transcatheter closure(100%)as effective as surgical closure.Less than small residual shunt was present 20%and 8%immediately after the procedure in the transcatheter and surgical groups(p=0.50),which decreased to 12%and 4%at the 1-year follow-up(p=0.61),respectively.No incidence of complete atrioventricular block and other complications was observed in both groups,and no significant differences were noted in the new onset or worsening of the aortic regurgitation in both groups(p=1.0).Conclusions:Transcatheter treatment could be effectively and safely achieved for OVSD closure at 1-year follow-up.

侧式进 出水口顶板扩张角对拦污栅断面流速分布影响规律研究

抽水蓄能电站侧式进出水口双向过流,其顶板扩张角的大小将直接影响拦污栅断面流速分布是否均匀,甚至出现反向流速。抽水蓄能电站设计规范将3°~5°作为侧式进出水口顶板扩张角的推荐范围,其依据是矩形渐扩管阻力系数最小的扩张角度,但侧式进出水口体型较之复杂很多,因此有必要进一步探讨。本文以某侧式进出水口体型为研究对象,采用数值模拟方法,研究了11种角度的顶板扩张角对出流工况和进流工况拦污栅断面流速分布的影响。结果表明:在出流工况下,随着顶板扩张角的增大,中孔拦污栅断面的主流位置由居中部逐渐向底部降低,断面流速分布由上下基本对称趋于底部大上部小的上下不对称,当顶板扩张角较大时中孔拦污栅断面上部出现反向流速;随着顶板扩张角的增大,边孔拦污栅断面流速分布由基本均匀逐渐变为底部大上部小的不均匀分布;随着顶板扩张角的增大,中、边孔孔口流速不均匀系数均逐渐增大,但中孔拦污栅断面流速分布受顶板扩张角影响更大。在进流工况下,随着顶板扩张角的增大,中、边孔拦污栅断面流速分布及孔口流速不均匀系数均无明显影响。研究成果可为优化侧式进出水口设计提供指导。

混合式抽水蓄能电站对下泄水温影响的数值模拟研究

【目的】混合式抽水蓄能电站运行特性与常规电站相比存在差异,本文旨在掌握抽水蓄能电站水温的变化规律,为水库管理调度提供参考。【方法】以紧水滩水库为研究对象,采用MIKE3水温模型模拟不同进/出水口高程以及不同抽水流量工况的下泄水温,据此探讨混合式抽水蓄能电站对下泄水温的影响。【结果】抽蓄水流会对下泄水温产生影响,相对于现状无抽水工况的下泄水温,抽蓄工况下的下泄水温基本表现为5—9月略有下降,其余月份略有升高,下泄水温的最大降幅不超过0.7℃,最大升幅不超过0.8℃。【结论】进/出水口高程对于下泄水温影响较大,且高程越低,下泄水温差异越大。然而抽水流量对于下泄水温差异影响并不显著,但整体上也呈现出随着抽水流量增加,水温差异增大的趋势。

侧式进/出水口水头损失系数多元线性回归分析

进/出水口水头损失是抽水蓄能电站输水系统水头损失的重要组成部分,准确计算水头损失是评估电站运行经济效益的重要需求。本文通过数值模拟方法研究了14个实际侧式进/出水口的水头损失系数;利用多元线性回归方法,建立了基于侧式进/出水口体型参数计算水头损失系数的回归方程,分析了侧式进/出水口体型参数对其水头损失系数的影响规律。结果表明:侧式进/出水口体型参数对水头损失系数的影响程度,对出流工况较显著,而对进流工况不显著;出流工况,侧式进/出水口体型参数对水头损失系数的相关性,扩散段长度、扩散段分流墩中墩缩进距离、水平扩散角、垂向扩散角、分流墩墩头中边孔宽度比和反坡段坡比为正相关,调整段长度和防涡梁段长度为负相关;利用回归方程得到的水头损失系数与数值模拟方法的结果吻合较好。本文建立的回归方程为计算侧式进/出水口水头损失系数提供了新方法。