Assessing Sprinkler Irrigation Performance Using Field Evaluations at the Medjerda Lower Valley of Tunisia

Irrigation uniformity and wind drift and evaporation losses (WDEL) are major concerns for the design and management of sprinkler irrigation systems under arid or semi-arid conditions. Field trials were carried out to assess irrigation uniformity and WDEL under various wind velocities, sprinkler spacings and operating pressure heads. Based on experimental data, a frequency analysis was performed to infer the occurrence probability of a given uniformity coefficient (UC). In addition, statistical regressions were used to model WDEL as a function of different climatic variables. Increasing the operating pressure head improved uniformity at low wind speeds. It was shown that UC has been severely impaired at wind speeds above 4 m/s. In the prevailing wind conditions, the frequency analysis showed that a sprinkler spacing of 12 m × 12 m provided the best uniformity. In the local conditions, it is recommended to stop irrigation when wind velocity exceeds 4 m/s. Moreover, it was shown that wind speed and relative humidity were the main significant variables influencing WDEL.

棒材DROF工艺粗轧阶段工艺参数对轧件头尾温差的影响

针对棒材免加热直接轧制技术在轧制生产中常有轧件温度头低尾高以及同批次产品头尾性能差异较大等问题,以某钢铁公司实际棒材直轧生产线为参考,以粗轧阶段轧制工艺参数为研究对象,利用ABAQUS有限元软件建立了粗轧阶段三维热力耦合模型,从优化粗轧阶段轧制速度、轧辊直径和延伸系数等相关工艺参数角度研究改进头尾温差的方法。研究结果表明,轧件头尾温差随轧制速度的减小而降低,随辊径的减小而降低,随延伸系数的增大而降低,通过优化以上粗轧阶段相关工艺参数可以使轧件头尾温差降低20℃以上,缩小同批次产品的性能波动。

基于VOF模型研究相邻叶片交错角对水车性能的影响

为了探究影响3叶片下击式水车性能的因素,利用流体体积(VOF)模型模拟明渠无压流动,基于SST k-ω湍流模型、PISO算法及滑移网格旋转模型对相邻叶片不同交错角度(0°、20°、40°、60°)的水车进行非定常模拟。计算结果表明:当相邻叶片交错角度为0°时,对应的水车高效区最为宽广且最优效率最高,叶轮前后区域压力基本呈对称分布;随着交错角度增加,前后压力分布差异逐渐变大。相同工况下,旋转一周水车转矩的平均值从小到大依次为60°、40°、20°、0°,但不稳定性也依次增大。此外,水车的效率随叶尖速比的增加呈现先增大后减小的趋势;转矩的波动幅度随叶尖速比的减小而降低。

In vivo testing of a bone graft containing chitosan, calcium sulfate and osteoblasts in a paste form in a critical size defect model in rats

Bone loss associated with musculoskeletal trauma or metabolic diseases often require bone grafting. The supply of allograft and auto-graft bones is limited. Hence, development of synthetic bone grafting materials is an active area of research. Chitosan, extracted from chitin present in crawfish shells, was tested as a de-livery vehicle for osteoblasts in a 2-3 mm size defect model in rats. Twenty-seven male Lewis rats, divided into three groups with sacrifice intervals of 3, 6 &9 months were used. In the experimental samples, a critical size defect was filled with chitosan bone graft paste and fixed with a plate, while in the operated control group, a critical size defect was repaired only by a plate (no paste was applied). An unoperated control group was also included. Bone growth was evaluated histologically by examining undecal-cified and decalcified stained sections. The fe-murs were also examined non-destructively by micro-computed tomography (礐T). Defects filled with chitosan bone graft paste demon-strated superior healing across all time periods compared to unfilled defects as examined by histology and micro-computed tomography. Crawfish chitosan has successfully been used as a cell delivery system for osteoblasts for use as a synthetic bone graft material.

Implementation of K-Means Algorithm and Dynamic Routing Protocol in VANET

With the growth of Vehicular Ad-hoc Networks,many services delivery is gaining more attention from the intelligent transportation system.However,mobility characteristics of vehicular networks cause frequent disconnection of routes,especially during the delivery of data.In both developed and developing countries,a lot of time is consumed due to traffic congestion.This has significant negative consequences,including driver stress due to increased time demand,decreased productivity for various personalized and commercial vehicles,and increased emissions of hazardous gases especially air polluting gases are impacting public health in highly populated areas.Clustering is one of the most powerful strategies for achieving a consistent topological structure.Two algorithms are presented in this research work.First,a k-means clustering algorithm in which dynamic grouping by k-implies is performed that fits well with Vehicular network’s dynamic topology characteristics.The suggested clustering reduces overhead and traffic management.Second,for inter and intra-clustering routing,the dynamic routing protocol is proposed,which increases the overall Packet Delivery Ratio and decreases the End-to-End latency.Relative to the cluster-based approach,the proposed protocol achieves improved efficiency in terms of Throughput,Packet Delivery Ratio,and End-to-End delay parameters comparing the situations by taking different number of vehicular nodes in the network.

A Practical Speed Loss Prediction Model at Arbitrary Wave Heading for Ship Voyage Optimization

This paper proposes a semi-empirical model to predict a ship’s speed loss at arbitrary wave heading.In the model,the formulas that estimate a ship’s added resistance due to waves attacking from different heading angles have been further developed.A correction factor is proposed to consider the nonlinear effect due to large waves in power estimation.The formulas are developed and verified by model tests of 5 ships in regular waves with various heading angles.The full-scale measurements from three different types of ships,i.e.,a PCTC,a container ship,and a chemical tanker,are used to validate the proposed model for speed loss prediction in irregular waves.The effect of the improved model for speed loss prediction on a ship’s voyage optimization is also investigated.The results indicate that a ship’s voyage optimization solutions can be significantly affected by the prediction accuracy of speed loss caused by waves.

Boron delivery agents for neutron capture therapy of cancer

Boron neutron capture therapy(BNCT)is a binary radiotherapeutic modality based on the nuclear capture and fission reactions that occur when the stable isotope,boron-10,is irradiated with neutrons to produce high energy alpha particles.This review will focus on tumor-targeting boron delivery agents that are an essential component of this binary system.Two low molecular weight boron-containing drugs currently are being used clinically,boronopheny-lalanine(BPA)and sodium borocaptate(BSH).Although they are far from being ideal,their therapeutic efficacy has been demonstrated in patients with high grade gliomas,recurrent tumors of the head and neck region,and a much smaller number with cutaneous and extra-cutaneous melanomas.Because of their limitations,great effort has been expended over the past 40 years to develop new boron delivery agents that have more favorable biodistribution and uptake for clinical use.These include boron-containing porphyrins,amino acids,polyamines,nucleosides,peptides,monoclonal antibodies,liposomes,nanoparticles of various types,boron cluster compounds and co-polymers.Cur-rently,however,none of these have reached the stage where there is enough convincing data to warrant clinical biodistribution studies.Therefore,at present the best way to further improve the clinical efficacy of BNCT would be to optimize the dosing paradigms and delivery of BPA and BSH,either alone or in combination,with the hope that future research will identify new and better boron delivery agents for clinical use.

Advances in nanomaterials for the diagnosis and treatment of head and neck cancers:A review

Nanomaterials(NMs)have increasingly been used for the diagnosis and treatment of head and neck cancers(HNCs)over the past decade.HNCs can easily infiltrate surrounding tissues and form distant metastases,meaning that most patients with HNC are diagnosed at an advanced stage and often have a poor prognosis.Since NMs can be used to deliver various agents,including imaging agents,drugs,genes,vaccines,radiosensitisers,and photosensitisers,they play a crucial role in the development of novel technologies for the diagnosis and treatment of HNCs.Indeed,NMs have been reported to enhance delivery efficiency and improve the prognosis of patients with HNC by allowing targeted delivery,controlled release,responses to stimuli,and the delivery of multiple agents.In this review,we consider recent advances in NMs that could be used to improve the diagnosis,treatment,and prognosis of patients with HNC and the potential for future research.

Heuristic algorithms for scheduling on uniform parallel machines with heads and tails

This paper considers the uniform parallel machine scheduling problem with unequal release dates and delivery times to minimize the maximum completion time.For this NP-hard problem,the largest sum of release date,processing time and delivery time first rule is designed to determine a certain machine for each job,and the largest difference between delivery time and release date first rule is designed to sequence the jobs scheduled on the same machine,and then a novel algorithm for the scheduling problem is built.To evaluate the performance of the proposed algorithm,a lower bound for the problem is proposed.The accuracy of the proposed algorithm is tested based on the data with problem size varying from 200 jobs to 600 jobs.The computational results indicate that the average relative error between the proposed algorithm and the lower bound is only 0.667%,therefore the solutions obtained by the proposed algorithm are very accurate.

Normal Range of Head-to-body Delivery Interval by Two-step Delivery

Background： The one-step method was routine practices in China, scientific evidence to support this intervention is scarce. The purpose of this study was to observe the natural process of head-to-body delivery interval by waiting for at least one contraction （two-step） after head delivered in normal birth. Methods： From March 1 to March 30 in 2015 at Haikou Maternal and Child Hospital in China, normal vaginal birth with normal baby condition were recorded by video. Videotapes were transferred to computer then replayed and observed. Results： Ninety-two cases were enrolled in this study. The average head-to-body delivery interval by two-step delivery was 71.04± 61.02 s, （mean ＋ 2 standard deviation - 193.07 s, 95% confidence interval [15.65-229.15] s）. Fifty-one patients （51/92, 55.43%） were 〈60 s, 41 patients （41/92, 44.57%） were over 60 s. Shoulders delivered at the first contraction were 96.74% （89/92）, 3.26% （3/92） had delivered by the second contraction. Shoulders emerged from perineum were 71.73% （66/92）, 15.21% （14/92） transversely, and 13.04% （12/92） emerged from under pubic arch. Babies cried before the shoulder were 31.52% （29/92）, cried after birth 52.17% （48/92）, and 16.30% （15/92） did not cry after birth. Baby activities included as making faces, sucking, and bubbled from mouth and noses, and the lighter blue color of skin with good perfusion. Conclusions： The average time of head-to-body delivery interval was longer than 60 s by two-step delivery. Majority shoulders were delivered at the first contraction. Majority shoulders emerged from perineum rather from under pubic arch. The routine one-step method of shoulder delivery where the downward force applied is not necessary and is not the right direction. Baby＇s breath, making faces, sucking, bubble from noses and mouth, and the light blue color of the faces, all those signs during shoulder delivery indicated a normal live birth.

考虑随机需求的高铁快递运输计划优化方法

为了充分利用高速铁路非高峰期的列车运输能力,提升高速铁路运营的经济效益,研究载客动车组客货共运模式下的高铁快递运输计划优化问题。首先,考虑高铁快递运输需求的时效性与随机性,以最大化高铁快递运营企业期望总利润为优化目标,同时满足列车运输能力、车站装卸效率、标准箱到发量守恒等约束,构建高速铁路快递运输计划优化的2阶段随机规划模型。在第1阶段,以最大化高铁快运期望总利润为目标,确定各列车的运输能力分配计划;在第2阶段,根据第1阶段获得的列车运输能力分配计划,确定随机需求场景下的高铁快递实际装运方案,使该场景下的运营收益达到最大。其次,基于蒙特卡洛模拟随机生成需求场景,采用反向消减算法(BRA)将2阶段随机规划模型转化为包含有限场景数的确定性整数线性规划模型,从而调用商业求解器GUROBI进行求解。最后,以宁杭高速铁路为背景进行算例分析,验证模型和算法的有效性。结果表明,相较于基于确定性需求得到的运输计划,利用随机规划方法得到的方案更能适应需求的随机性,从而达到更好的盈利效果,同时可以兼顾服务水平与企业收益,适用于实际运营中高铁快递运输计划的设计与优化。

产钳保留原位方法娩出胎头且会阴不侧切母婴结局分析

目的:探讨在低位产钳助产中,采用产钳保留原位方法娩出胎头且会阴不侧切对产妇和新生儿结局的影响。方法:选择2021年1月至2023年4月在南京医科大学附属妇产医院经阴道分娩行低位产钳术且会阴不侧切产妇63例进行回顾性分析,依据取出产钳时间不同分为产钳保留原位方法娩出胎头组(观察组,37例)和提早取出产钳方法娩出胎头组(对照组,26例),比较两组产妇和新生儿结局差异。结果:两组产妇均无肩难产和会阴Ⅳ度裂伤。两组的会阴裂伤程度、阴道裂伤、阴道血肿、子宫颈裂伤、产后出血分娩并发症比较,差异均无统计学意义(P>0.05)。两组产妇全部活产,产钳助产至胎儿娩出时间比较差异无统计学意义(P>0.05)。两组新生儿均无重度窒息、颅内出血和死亡,新生儿钳痕、颜面部擦伤和轻度窒息占比差异均无统计学意义(P>0.05)。结论:产钳保留原位较提早取出产钳方法娩出胎头应用于会阴不侧切,不增加会阴损伤,不增加相关母婴并发症,是一项实用且安全的临床技术。

手转胎头联合夸张膀胱截石位在头位难产中的作用研究

目的探讨手转胎头联合夸张膀胱截石位在头位难产中的作用。方法选取2022年1月至2023年2月于萍乡市人民医院收治的90例头位难产(cephalic dystocia,CD)产妇作为研究对象,按照随机数字表法分为对照组、实验A组与实验B组,各30例。对照组行常规处理措施,实验A组行手转胎头术,实验B组行手转胎头术联合夸张膀胱截石位。比较3组产后出血量、新生儿Apgar评分、分娩结局(阴道助产、自然分娩、剖宫产)及新生儿并发症发生情况。结果实验B组产后出血量少于实验A组、对照组,新生儿Apgar评分高于实验A组、对照组,且产后出血量少于对照组,新生儿Apgar评分高于对照组,差异有统计学意义(P<0.05)。3组阴道助产率、剖宫产率比较差异无统计学意义;实验B组自然分娩率高于对照组,差异有统计学意义(P<0.05)。3组新生儿窒息发生率比较差异无统计学意义;3组宫内窘迫发生率比较差异有统计学意义(P<0.05);实验B组宫内窘迫发生率发生率低于对照组,差异有统计学意义(P<0.05)。结论手转胎头术联合夸张膀胱截石位助产CD产妇,能有效减少产后出血量,提高新生儿Apgar评分及产妇自然分娩率,减少宫内窘迫的发生,值得临床推广应用。

头位分娩评分法在4000例孕妇分娩过程中的应用

目的 探讨头位分娩评分法在孕妇分娩过程中的应用价值。方法 选取2020年1月—2022年12月于郑州市妇幼保健院进行建档住院的4 000例待产分娩孕妇作为研究对象,所有孕妇在宫口已开时都给予头位分娩评分,观察与记录所有孕妇的分娩方式与头位分娩评分法状况,记录新生儿出生1 min与出生5 min的Apgar评分,记录所有孕妇的产后并发症发生情况。结果 在4 000例孕妇中,Apgar评分≤8分者156例、9~10分者894例、≥11分者2 950例。不同头位分娩评分法孕妇的年龄、孕周、孕次、产次对比差异无统计学意义(P>0.05)。≤8分者的剖宫产率为100.0%,9~10分者、≥11分者分别为35.3%、5.7%,对比差异有统计学意义(P<0.05)。≤8分者、9~10分者、≥11分者的新生儿出生1 min与出生5 min的Apgar评分对比差异无统计学意义(P>0.05)。≤8分者、9~10分者、≥11分者的产后发热、产后出血、产后血肿、产后尿潴留等并发症发生率为分别为13.5%、2.0%、0.2%,对比差异有统计学意义(P<0.05)。结论 头位分娩评分法在产科中处理头位分娩时具有指导价值,值得推广应用。

抽水蓄能电站单机容量与机组转速选择

通过分析国内外已建抽水蓄能电站机组主要技术参数,研究抽蓄电站定转速混流式水泵水轮机水头与单机容量、参数水平的关系,提出了不同水头段抽水蓄能电站单机容量和比速系数选择原则,推荐了合适的机组额定转速范围,可提高抽水蓄能电站水泵水轮机选型设计的工作效率和成果质量。

综掘工作面风流调控下风速及瓦斯粉尘浓度融合预测模型研究

针对综掘工作面传统的通风总量控制管理模式不能根据实际需求进行风流调控,造成瓦斯及粉尘聚集和污染隐患等问题,对风流调控下的风速及瓦斯粉尘浓度多源数据融合神经网络预测模型进行了研究。采用欧拉-拉格朗日法建立了风流调控下的瓦斯及粉尘气固耦合模型并进行了测试验证,模拟分析瓦斯和粉尘颗粒在综掘巷道的分布情况,获取大量不同风流调控方案下的风速及瓦斯粉尘浓度样本数据。采用多层感知器神经网络技术建立预测模型结构,选取对瓦斯及粉尘浓度具有较大影响的风流调控等参数作为输入层,根据风速及瓦斯粉尘的隐患位置确定输出层,对样本数据进行预处理,通过引入差分进化算法搜索最佳隐藏层节点数和学习率,利用TensorFlow框架搭建多源数据融合神经网络预测模型。以陕北某矿综掘工作面为研究对象,对不同风流调控方案进行预测和井下实测验证。结果表明:该模型相对误差最大值为9.7%,具有较高的准确性;选取出风口距端头最短距离5 m和最远距离10 m这2种工况下的最佳调控方案,与调控前相比,风速符合规范要求,端头死角区瓦斯体积分数分别降低34%和35%,回风侧人行处平均粉尘质量浓度分别降低40%和41%,司机处粉尘质量浓度分别降低38%和36%,研究可为风流调控提供参考。

徒手旋转胎头术在头位难产产妇第二产程分娩中的协助应用观察

目的:分析徒手旋转胎头术在头位难产产妇第二产程分娩中的协助应用效果。方法:回顾性分析2020年1月至2023年12月于本院分娩的56例头位难产产妇资料,依据第二产程是否使用徒手旋转胎头术分为两组,各28例。对照组采取传统第二产程分娩助产护理,观察组采取第二产程徒手旋转胎头术,统计产程总时间、新生儿神经行为评分、分娩结局并进行对比。结果:观察组的第二分娩产程明显短于对照组,观察组产程总时间明显短于对照组(P<0.05),第一和第三产程两组无明显统计差异(P>0.05);观察组新生儿神经行为各项评分均高于对照组(P<0.05);观察组阴道裂伤、新生儿窒息及产后出血率均低于对照组(P<0.05)。结论:第二产程徒手旋转胎头术的运用能够改善头位难产产妇分娩结局、促进新生儿神经行为发育、缩短产程总时间,具有一定的推广使用价值。

高水头电站水轮机泥沙磨损评估及抗磨蚀综合措施

对于高水头电站,泥沙磨损的影响在水轮机的设计和参数选择中是一个不可忽视的问题。以科哈拉水电站为例,根据电站的泥沙特性,对水轮机的泥沙磨损进行试验和评估。从水轮机参数选择、水力设计、结构及工艺、材料及表面防护、调度运行等方面提出了针对性的抗泥沙磨蚀综合措施。研究内容可为其他高水头电站水轮机抗磨蚀方案的设计提供参考。

基于S形速度曲线的键合头运动控制系统研究与分析

根据用户工艺需求,针对全自动芯片键合设备的运动控制模块以及键合头子模块开展需求分析,结合典型试验,设计出基于S形速度曲线的键合头运动控制系统,根据S形速度曲线重新规划了键合头的运动轨迹,使其对芯片键合周期缩短的同时也保证了键合精度。

闸墙长廊道侧支孔船闸阀门运行方式优化试验研究

船闸阀门开启时间对闸室通航效率、输水廊道压力和闸室停泊条件等产生影响,针对阀门运行方式优化问题,采用物理模型试验对船闸进水口水位、阀门段输水廊道压力特性、闸室和下引航道内船舶系缆力等水力特性进行分析,结果表明:闸室和下引航道内前横、后横和纵向3个方向的船舶系缆力均随阀门开启时间增大而减小,且纵向船舶系缆力大于横向船舶系缆力。随着阀门开启时间增加,充水时阀门段输水廊道压力先减小后增大,泄水时则逐渐增大。综合考虑当阀门开启时间为6 min时船闸整体运行效果较好,该成果可为实际船闸运行提供技术支撑。