Pressure Drop of Liquid–Solid Two-Phase Flow in the Vertical Tube Bundle of a Cold-Model Circulating Fluidized Bed Evaporator

A cold-model vertical multi-tube circulating fluidized bed evaporator was designed and built to conduct a visualization study on the pressure drop of a liquid–solid two-phase flow and the corresponding particle distribution.Water and polyformaldehyde particle(POM)were used as the liquid and solid phases,respectively.The effects of operating parameters such as the amount of added particles,circulating flow rate,and particle size were systematically investigated.The results showed that the addition of the particles increased the pressure drop in the vertical tube bundle.The maximum pressure drop ratios were 18.65%,21.15%,18.00%,and 21.15%within the experimental range of the amount of added particles for POM1,POM2,POM3,and POM4,respectively.The pressure drop ratio basically decreased with the increase in the circulating flow rate but fluctuated with the increase in the amount of added particles and particle size.The difference in pressure drop ratio decreased with the increase in the circulating flow rate.As the amount of added particles increased,the difference in pressure drop ratio fluctuated at low circulating flow rate but basically decreased at high circulating flow rate.The pressure drop in the vertical tube bundle accounted for about 70%of the overall pressure drop in the up-flow heating chamber and was the main component of the overall pressure within the experimental range.Three-dimensional phase diagrams were established to display the variation ranges of the pressure drop and pressure drop ratio in the vertical tube bundle corresponding to the operating parameters.The research results can provide some reference for the application of the fluidized bed heat transfer technology in the industry.

Cross influence of discharge and circulation on head loss of conduit of pump system with low head

The relationship between the head loss and the discharge and circulation of the conduit of a pump system with low head is an important problem with an obvious influence on the improvement of its hydraulic performance. The velocity circulation from the pump guide vane makes the relationship more complicated, which has to be understood comprehensively. The results indicate that, under the condition of zero circulation, the head loss of the inlet and outlet conduits is in proportion to the square of discharge. Under the condition that the Reynolds number is satisfied with the resistant square area, the conduit loss is in proportion to the square of discharge for the similar working points with different speeds in a certain rotational speed range, indicating that the pump system efficiency is constant. The outlet conduit loss of design discharge for a pump system with low head depends on the velocity circulation from the guide vane exit, and the relationship between the loss and the circulation is an open curve with an upward direction, meaning that there is an optimal circulation for the loss. Under the condition of various working points for a pump system with low head, the head loss of the outlet conduit is under the cross influence of both the discharge and the circulation. As a result, the relationship between the head loss and the discharge is almost linear, and the mechanism needs to be further studied.

Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats

AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion. METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15(IO-15), 20(IO-20) and 30(IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed. RESULTS: At 60 minutes after reperfusion following a total of 60 minutes of hepatic inflow occlusion, EC values in IO-10 (0.749 +/- 0.012) and IO-15 (0.699 +/- 0.002) groups were rapidly restored to that in SO group (0.748 +/- 0.016), TTC reduction activities remained in high levels (0.144 +/- 0.002 mg/mg protein, 0.139 +/- 0.003 mg/mg protein and 0.121 +/- 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 +/- 0.023 and 0.534 +/- 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 +/- 0.005 mg/mg protein and 0.061 +/- 0.003 mg/mg protein). No recovery in EC values (0.228 +/- 0.004) and a progressive decrease in TTC reduction activities (0.033 +/- 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD(3)) and POD(7) and of the serum alanine aminotransferase (ALT) on POD(3) in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group. CONCLUSION: Hepatic inflow occlusion during 60 minutes for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.

Promotion of structural plasticity in area V2 of visual cortex prevents against object recognition memory deficits in aging and Alzheimer's disease rodents

Memory deficit,which is often associated with aging and many psychiatric,neurological,and neurodegenerative diseases,has been a challenging issue for treatment.Up till now,all potential drug candidates have failed to produce satisfa ctory effects.Therefore,in the search for a solution,we found that a treatment with the gene corresponding to the RGS14414protein in visual area V2,a brain area connected with brain circuits of the ventral stream and the medial temporal lobe,which is crucial for object recognition memory(ORM),can induce enhancement of ORM.In this study,we demonstrated that the same treatment with RGS14414in visual area V2,which is relatively unaffected in neurodegenerative diseases such as Alzheimer s disease,produced longlasting enhancement of ORM in young animals and prevent ORM deficits in rodent models of aging and Alzheimer’s disease.Furthermore,we found that the prevention of memory deficits was mediated through the upregulation of neuronal arbo rization and spine density,as well as an increase in brain-derived neurotrophic factor(BDNF).A knockdown of BDNF gene in RGS14414-treated aging rats and Alzheimer s disease model mice caused complete loss in the upregulation of neuronal structural plasticity and in the prevention of ORM deficits.These findings suggest that BDNF-mediated neuronal structural plasticity in area V2 is crucial in the prevention of memory deficits in RGS14414-treated rodent models of aging and Alzheimer’s disease.Therefore,our findings of RGS14414gene-mediated activation of neuronal circuits in visual area V2 have therapeutic relevance in the treatment of memory deficits.

Visual Loss after Cardiopulmonary Bypass (CABG) for Coronary Artery Disease: A Report of Case

We are reporting a 59-year-old male who presented with features of bilateral anterior ischaemic optic neuropathy after coronary artery bypass grafting. Postoperative vision loss after major nonocular surgery is a very rare but devastating complication since it has the potential to cause bilateral, severe and permanent loss of vision.

Graft loss among renal-transplant recipients with early reduction of immunosuppression for BK viremia

AIM To review the incidence of graft loss and acute rejection among renal transplant recipients with early reduction of immunosuppression for BK viremia.METHODS We performed a retrospective analysis of consecutive de-novo kidney-only transplants from January 2009 to December 2012 to evaluate the incidence of Polyomavirus associated nephropathy(PyV AN). Recipient plasma was screened for BKV DNA via quantitative polymerase chain reaction(PCR) at months 1,3,6,9 and 12 post-transplant and on worsening graft function.Immunosuppression was reduced at ≥ 3-log copies/mL. Those with viremia of ≥ 4-log copies/mL(presumptive PyV AN) underwent renal transplant biopsy. Presumptive Py VAN(PP) and definitive Py VAN(DP; biopsy-proven) were treated by immunosuppression reduction(IR) only. RESULTS Among 319 kidney transplant recipients,the median age was 53 years(range 19-83),65.8% were male,and 58.9% were white. Biopsy-proven acute rejection was found in 18.5% within 0-168 wk. Death-censored graft loss occurred in 5.3%(n = 17) and graft loss attributable to PyV AN was 0.6%(n = 2). Forty-seven patients were diagnosed with PP(14.7%) and 18(5.6%) with DP. Graft loss among participants with PyV AN(8.5%) and those without(4.8%) was not significantly different. Deceased donor kidney transplantation(OR = 2.3,95%CI = 1.1-4.6) and AR(OR = 2.3,95%CI = 1.2-4.7) were associated with Py VAN in the multivariate analysis. BK viremia between 3 and 4-log copies/mL occurred in 27 patients,all of whom underwent IR. Of these,16(59%) never developed PyV AN while 11(41%) developed PyV AN(4 DP,7 PP) within a range of 11-39 wk. CONCLUSION Instituting an early reduction of immunosuppression,in the absence of adjunctive antivirals,is effective at preventing PyV AN and may be associated with a lower incidence of graft-loss without a reciprocal increase in the incidence of acute rejection.

Development of a New Diagnostic Method for LostCirculation in Directional Wells

Failure to manage and minimize lost circulation can greatly increase the cost of drilling and the risk of well abandonment.Many lost circulation remedial procedures are not working as planned because the locations of loss zones are incorrectly estimated.The lack of this critical piece of information prevents treatments from being applied directly to the points of losses and, thus,resulting in low efficiency and extended NPT （non-productive time）. This paper presents an integrated method for identifying thelocations of loss zones with continuous temperature measurement data enabled by drilling microchip technology. A transient thermalmodel in predicting the temperature profiles in the wellbore and formation during mud loss is developed as a forward calculationprocedure of the loss zone mapping method. For a deep well with moderate to severe loss, there are significant changes in the mudcirculating temperature profiles as mud loss persists. Certain characteristics ofwellbore thermal behavior are evaluated and identifiedas good indicators of loss zones. Case studies are conducted to demonstrate the practical applications of the method in both onshoreand offshore drilling applications. The results from these case studies are important in setting cement plugs, applying expandabletubular systems, and spotting LCM （lost circulation material） pills. Additional uses of this method include identifying highlypermeable zones for reservoir or formation evaluation purposes. This method can be used as a routine monitoring process performedregularly without any interference of the drilling operations at the time.

A New Mechanism of Hinokitiol as An Active for Hair Loss Prevention

Hair loss and gray hair are the ultimate manifestations of scalp and hair aging.Improving metabolic activities in cells is a fundamental for anti-aging while autophagy activity of cell is a key measure.Hinokitiol,one of the more than 30 quasi-drug actives approved in Japan in the field of hair tonic products has two known mechanisms for its effectivities,i.e.promoting cell activity and anti-microbial.Through this study,we identified a new mechanism of hinokitiol for hair loss prevention,i.e.promotion of autophagy and mitophagy activities of dermal papilla cells.

Atmospheric responses over Asia to sea ice loss in the Barents and Kara seas in mid late winter and early spring:a perspective revealed from CMIP5 data

This study investigated atmospheric responses in mid late winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the January March mean atmosphere on Barents and Kara sea ice area in November and December.Similar atmospheric circulation responses were obtained from reanalysis data and multimodel ensemble results from the Coupled Model Intercomparison Project Phase 5,i.e.,sea ice anomalies are the dominant factor driving the overlying atmosphere.The results showed that an Arctic Asia dipole structure,with opposite anomalies over the mid-latitudes of Asia and over the adjoining Arctic,appears to be the key atmospheric circulation anomaly influencing the East Asian climate in mid late winter and early spring.

Structural failure mechanism and strengthening method of fracture plugging zone for lost circulation control in deep naturally fractured reservoirs

Focused on the lost circulation control in deep naturally fractured reservoirs, the multiscale structure of fracture plugging zone is proposed based on the theory of granular matter mechanics, and the structural failure pattern of plugging zone is developed to reveal the plugging zone failure mechanisms in deep, high temperature, high pressure, and high in-situ stress environment. Based on the fracture plugging zone strength model, key performance parameters are determined for the optimal selection of loss control material(LCM). Laboratory fracture plugging experiments with new LCM are carried out to evaluate the effect of the key performance parameters of LCM on fracture plugging quality. LCM selection strategy for fractured reservoirs is developed. The results show that the force chain formed by LCMs determines the pressure stabilization of macro-scale fracture plugging zone. Friction failure and shear failure are the two major failure patterns of fracture plugging zone. The strength of force chain depends on the performance of micro-scale LCM, and the LCM key performance parameters include particle size distribution, fiber aspect ratio, friction coefficient, compressive strength, soluble ability and high temperature resistance. Results of lab experiments and field test show that lost circulation control quality can be effectively improved with the optimal material selection based on the extracted key performance parameters of LCMs.

Integrated Prevention and Control System for Soil Erosion in Typical Black Soil Region of Northeast China

The black soil region of Northeast China is one of the most important food production bases and commodity grain bases in China. However, the continual loss and degradation of precious black soil resources has led to direct threats to national food security and regional sustainable development. Therefore, it is necessary to summarize integrated prevention and control experience of small watersheds in black soil region of Northeast China. Tongshuang small watershed, a typical watershed in rolling hills of typical black soil areas in Northeast China, is selected as the study area. Based on nearly 50 years' experience in prevention and control of soil and water loss, the structures and overall benefits of an integrated prevention and control system for soil and water loss are investigated. Then, the 'three defense lines' tri-dimensional protection system with reasonable allocation of different types of soil and water control measures from the hill top to gully is systematically analyzed. The first line on the top hill can weaken and block uphill runoff and sediment, hold water resources and improve soil property. The second line on the hill can truncate slope length, slow down the runoff velocity and reduce erosion energy. The third line in the gully is mainly composed of waterfall engineering, which can inhibit soil erosion and restore land resources. The 'three defense lines' system is feasible for soil and water loss control of small watersheds in the typical black soil region of Northeast China. Through the application of the in Tongshuang small watershed, There are effective improvements in ecological conditions in Tongshuang small watershed after the application of 'three defense lines' soil and water control system. Moreover, the integrated treatment paradigm for soil and water loss in typical black soil region is compared with that in loess region. The results of this study could offer references and experiences for other small watersheds in typical black soil region of Northeast China.

A Review of Medium Voltage Single-Core Cable Armouring, Induced Currents and Losses

Insulated underground cables have the potential to reduce power outages, maintenance costs, and transmission losses compared to overhead lines. On the other hand, they are exposed to several risks and physical damages, since they are buried in the ground. Though the cables are armoured in order to provide mechanical protection and achieve tensile strength, and also to provide effective conductance of earth fault currents. The main purpose of this paper is to introduce insulated underground cables, armouring process, and to analyze the induced currents in metallic parts such as sheath and armour that causeohmic losses which are categorized mainly in two groups as circulating current and eddy current. This paper presents a review on analytical techniques used to analyze the effect of magnetic fields, andcalculate the losses in the armour of the cables, besides providing the strategies and solutions used for armour loss reduction.

华南地区城市建筑物防热节能控制指标的选取

根据建筑物热工气候分区及设计特点,对夏热冬暖地区建筑物防热和节能从不同环节进行了详细的分析研究,主要包括建筑物设计本身的体形构造和确定,门窗的材料及窗玻璃材料的选择、建筑物窗墙比例、不同的内外遮阳形式,建筑物墙体材料、墙体外表面处理,屋顶材料和屋顶不同型式的节能效应以及下垫面及绿化植被、水体景观等方面。这些措施是实现建筑防热节能的关键环节,综合这些措施可达到夏热冬暖地区建筑防热节能的热工要求。

Semaglutide’s Trail of Success in Weight Loss Management and HbA1c Reduction: A Systematic Review

Introduction: Obesity is a preventable health condition, yet it remains a complex relapsing global health conundrum, triggering an array of comorbidities, including diabetes, dyslipidemia, hypertension, and mental health decline. This review intends to highlight the success of semaglutide for its therapeutic intervention for weight loss management in diabetics and non-diabetics and HbA1c reduction in type 2 diabetics. Methods: We searched and systematically reviewed the literature from within the past ten years on semaglutide utilization for weight loss and HbA1c reduction. Databases investigated included PMC, JAMA, Nature Medicine, and The Lancet, resulting in four original research articles that were systematically reviewed. Web consultations with WHO, CDC, and Healthy People 2030 were conducted to ascertain epidemiological obesity and diabetes data. AAFP and USPSTF references were included for obesity management and preventive care guidelines. Results: Based on results from systematically reviewing four original research studies, semaglutide can effectively reduce elevated weight and HbA1c, using the once-weekly subcutaneous injection formulation. A composite average percent weight loss of 8.27% (16 - 20 pounds) and an average HbA1c percent reduction rate of 1.07% (3 - 4 points) were attained. There were no major adverse events reported from any of the four original research studies related to the drug. Discussion: With evidence from several studies after its FDA approval, semaglutide delivers a promise for weight loss management and HbA1c reduction for appropriate patient populations. Clinician and patient education on its proper use should be continuously revisited.

Preparation and properties of magnesium oxysulfate cement and its application as lost circulation materials

Loss of drilling fluids in large porous and fractured zones inevitably up-regulates the overall cost of drilling.As a type of acid-soluble cement,magnesium oxysulfate(MOS)cement is arousing huge attention for the less hygroscopic nature and less damaging to steel casings compared with magnesium oxychloride(MOC)cement.The present study developed MOS cement as a fast setting,high strength and acid-soluble lost circulation material to reduce the problem of losses.As suggested in this study,a higher strength of MOS cement at 70℃could be achieved by elevating M_(g)O/MgSO_(4)·7 H_(2)O molar ratio or downregulating H_(2)O/MgSO_(4)·7 H_(2)O molar ratio.Boric acid and borax could act as effective retarders.Plugging slurry based on MOS cement could effectively block the simulated porous loss zones exhibiting a diameter from 1.24 mm to 1.55 mm,as well as the fractured loss zones with a width from 2 mm to 5 mm and bearing a pressure difference up to 8 MPa.Permeability recovery test demonstrated that it facilitated future oil and gas production.The successful field application in the Junggar Basin,Xinjiang,China verified the significant plugging effect of MOS cement for severe loss problems.

钻井循环压耗计算修正系数方法及应用

通过对实际钻井循环系统分析,认为在钻井循环过程中把全循环过程看成紊流是有理论依据的、可行的和符合实际的。并结合工程实际,对常见的紊流压耗计算公式作分析,找出应用目前的压耗计算公式计算出现误差较大的原因。为了使压耗计算模式准确、实用、能适用于各种井况,把流体力学研究中的实验方法思想引入钻井循环压耗计算的数学模式,提出了压耗计算的动态数学模式。在模式中引入可实时测取的四个修正系数,以便对压耗计算模式作实时修正,同时给出了修正系数的现场获取方法,使压耗计算模式可应用于各种井况。此方法在东湾1井应用表明,具有较高的准确度。

财产保险防灾减损决策支持系统的开发

本文介绍了财产保险防灾减损决策支持系统的架构,从静态模型、动态模型和3S技术在系统中的应用这三方面对整个系统进行了功能描述,对系统的技术特点做了分析,并将原型系统在深圳市示范应用。在承灾体细化到保单、灾情多模式研究、3S技术在防灾减损中的应用以及灾情预测和损失评估模型方法的构建等方面,系统做了深入的发掘,取得了良好的应用效果。

医学3.0与健康管理2.0将促进健康中国战略的早日实现

以学术争鸣和观点述评的方式系统介绍医学3.0与健康管理2.0的观点和内容,通过对近年来因慢病导致死亡的数量远远超过战争所带来的死亡人数的分析和思考,指出慢病防控几乎是人类输得最惨的一场战争。通过对慢病防控这场战争进行反思和总结,结合国内外医学领域(含中医和西医)相关研究,指出以往对慢病起源及其发生发展过程出现的认识不足和失误以及相应的防控策略出现的方向性、战略性错误是导致慢病失控的关键因素,为此,需要重新全面认识慢病起源,并将慢病起源指向生活方式和饮食习惯的失衡所导致的肠道菌群紊乱这个关键点,其中的核心观点即"菌心说"学说认为,肠道菌群而并非大脑摄食中枢是驱动人体产生饥饿感,从而进行摄食的关键原因。为此,基于"饥饿源于菌群"与"慢病源于(肠道菌群向人体传递饥饿感而胁迫人体被动)摄食"所形成的"慢病源于菌群"的新观点,为将中医(医学1.0)和西医(医学2.0)升级到医学3.0阶段提供了科学依据,并顺应性地提出了健康管理2.0的新思路。由于近年来基于该新思路的技术方案已在肥胖、"三高"、荨麻疹、痛经等多种慢病(症状)的改善中陆续得到验证,因此进一步指出可将人体通过"一分为三"的辩证思维方式,理解为与人的三大功能(生物学功能、心理学功能、社会学功能)相对应的"两膜三区"新结构,即血脑屏障(BBB-1)和血菌屏障(BBB-2)这两个生物膜系统以及人体(肉体)、菌群(菌心)和人脑(认知)三个区域,其中肉体以人类基因组操作系统(OS/1)为代码运行,发挥为菌心和人脑提供能量(血糖)的作用,作为支撑菌心和人脑的支撑平台而存在,菌心以人体共生微生物尤其是肠道菌群基因组操作系统(OS/2)为代码运行,赋予人体饥饿感、人体对不同种类食物和数量的客观偏好性以及欲望、情商等依赖于物质的心理相关事件功能活动的物质基础,而人脑则以人类(区别于动物)所特有的语言、文字、符号及其逻辑等以操作系统(OS/3)为代码运行,赋予人类通过思维活动完成对客观世界以及主观世界的认识,从而形成人类的思想、精神、意志、信仰等高级表型和外在表现。由此可见,医学3.0不仅为慢病起源提供了新的认识论和慢病防控的方法论参考,而且对于如何认识人本身,进而认识到自然界的有序性以及人必须按照自然界的有序性而规范自己的言行,从而为确保身心健康提供了参考思路,期待在通过讨论和辩论进行深入论证和实践检验的基础上,促进这些新观点为人、医学以及社会的定义提供新的认识,加速促进健康中国战略的早日实现。

Machine learning for carbonate formation drilling: Mud loss prediction using seismic attributes and mud loss records

Due to the complexity and variability of carbonate formation leakage zones, lost circulation prediction and control is one of the major challenges of carbonate drilling. It raises well-control risks and production expenses. This research utilizes the H oilfield as an example, employs seismic features to analyze mud loss prediction, and produces a complete set of pre-drilling mud loss prediction solutions. Firstly, 16seismic attributes are calculated based on the post-stack seismic data, and the mud loss rate per unit footage is specified. The sample set is constructed by extracting each attribute from the seismic trace surrounding 15 typical wells, with a ratio of 8:2 between the training set and the test set. With the calibration results for mud loss rate per unit footage, the nonlinear mapping relationship between seismic attributes and mud loss rate per unit size is established using the mixed density network model.Then, the influence of the number of sub-Gausses and the uncertainty coefficient on the model's prediction is evaluated. Finally, the model is used in conjunction with downhole drilling conditions to assess the risk of mud loss in various layers and along the wellbore trajectory. The study demonstrates that the mean relative errors of the model for training data and test data are 6.9% and 7.5%, respectively, and that R2is 90% and 88%, respectively, for training data and test data. The accuracy and efficacy of mud loss prediction may be greatly enhanced by combining 16 seismic attributes with the mud loss rate per unit footage and applying machine learning methods. The mud loss prediction model based on the MDN model can not only predict the mud loss rate but also objectively evaluate the prediction based on the quality of the data and the model.

Structural formation and evolution mechanisms of fracture plugging zone

A coupled CFD-DEM method is used to simulate the formation process of fracture plugging zone.A photo-elastic system characterizing mesoscale force chain network developed by our own is used to model the pressure evolution in fracture plugging zone to reveal the evolution mechanism of the structure of fracture plugging zone.A theoretical basis is provided for improving the lost circulation control effect in fractured reservoirs and novel methods are proposed for selecting loss control materials and designing loss control formula.CFD-DEM simulation results show that bridging probability is the key factor determining the formation of fracture plugging zone and fracture plugging efficiency.Critical and absolute bridging concentrations are proposed as the key indexes for loss control formula design.With the increase of absolute bridging concentration,the governing factor of bridging is changed from material grain size to the combination of material grain size and friction force.Results of photo-elastic experiments show that mesoscale force chain network is the intrinsic factor affecting the evolution of pressure exerting on the fracture plugging zone and determines the macroscopic strength of fracture plugging zone.Performance parameters of loss control material affect the force chain network structure and the ratio of stronger force chain,and further impact the stability and strength of fracture plugging zone.Based on the study results,the loss control formula is optimized and new-type loss control material is designed.Laboratory experiments results show that the fracture plugging efficiency and strength is effectively improved.