Modification of the passive heamagglutination test for detection of <i>infectious bursal disease virus</i>

To modify the Passive Haemagglutination (PHA) test, a rapid test, used for qauntitative detection of viral antibodies, so that it can be used for determination of viral titres, dilutions of Infectious Bursal Disease Virus (IBDV) were used to sensitize the Red Blood Cells (RBCs) before reacting them with known IBD serum. Also, to improve sensitivity of the test, different RBC concentrations were used for the test. A standard IBDV gave positive PHA reaction upto its 1:2048 dilution. With different IBDV samples, positive PHA reactions occured upto dilutions, ranging from 1:16 to 1:4096. Different RBC concentrations gave different titres for same IBDV samples. With 0.6% and 0.2% RBC concentrations, mean PHA titres of IBDV samples increased from 454. 85 ± 315.32 to 2396.57 ± 489.55 (p < 0.05 ). It was concluded that PHA can be adopted for evaluation of viral titres. To improve sensitivity of the test, use of 0.2% RBC is recommended.

Technology and test results of space adaptability of passive hydrogen maser

Based on the operating principle and the electric property design of the passive hydrogen maser, the technology and test results of its space adaptability are carried out under the special launch conditions and space environment. The various perturbations affecting the output frequency of such a standard used for the navigation satellite system are specified, such as magnetic field change, vibration, thermal vacuum and radiation. Through the adaptability technology in the aspects above, the security and reliability of the space passive hydrogen maser sufficiently fulfill the requirements of space operation. At present, the space passive hydrogen maser is working normally on board, indicating that the space adaptability satisfies the design requirement.

Effect of Specific Verbal Instructions on the Identification of Pain Location during a Passive Straight Leg Raise Test

Musculoskeletal pain is common. Because pain is subjective, objectively describing it is crucial. However, pain assessment may cause distress in patients;therefore, physical therapists (PTs) should conduct these tests quickly and accurately. Simple and clear instructions are recommended for pain assessment. However, few studies have provided evidence to support this hypothesis. Correspondingly, this study aimed to confirm the effectiveness of specific verbal instructions for pain location during five consecutive Passive Straight Leg Raise (PSLR) tests. The 28 asymptomatic participants (age 27.4 ± 9.6 years) who provided informed consent received five consecutive PSLR tests: three without and two with specific verbal instructions to ascertain pain intensity, quality, and location. The participants drew pain locations on a body chart and described the pain intensity and quality after each test. All participants were interviewed regarding the differences they noted in the presence and absence of specific verbal instructions. Each pain location was classified into one of ten areas for statistical analysis. The proportion of participants who changed the pain location was compared between the tests using McNemar’s test, and the kappa coefficient was confirmed for consistency of pain location. There was a significant difference in the proportion of participants who changed their pain location between the second and third tests and from the third to the fourth test (McNemar’s test: p = 0.003). Kappa coefficients had low consistency (κ = 0.28) just after receiving the specific verbal instructions in the fourth test compared to the third test. Consistency improved in the fifth test (κ = 0.57);93% of the participants answered that the pain location had become clearer. This study revealed the effects of specific verbal instructions in identifying pain locations. This detailed information may help PTs provide appropriate treatment and contribute to reducing pain in clinical settings.

Effect of Verbal Instructions in Pain Assessment during a Passive Straight Leg Raise Test in People with Chronic Low Back Pain

The most prevalent issue in physical therapy is pain. Due to the subjective nature of pain, assessment tools are essential in understanding it as objective data. However, assessment of pain may result in distress for the patient. A physical therapist (PT) should conduct these tests as quickly and accurately as possible. Straightforward instructions are vital in such cases. This study aimed to clarify the effect of verbal instructions for pain assessment during a passive straight leg raise (PSLR) test for participants with chronic low back pain (CLBP). This study included 22 participants who provided informed consent and received three consecutive PSLR tests with measurement of the hip flexion range of motion (HFROM) and were instructed to cease the test at submaximal pain before the first test. Following the second and third tests, participants were given specific verbal instructions to remember pain intensity, quality, and location. After each test, participants were to circle the pain location on the body chart and rate their pain intensity on a numeric rating scale (NRS) and pain quality. All participants were then interviewed about the differences between having and not having specific verbal instructions. The results of HFROM, NRS, and pain extent were not significantly different between the first and second tests or between the second and third tests using a paired t-test. Eleven changes in pain location were found in the second test compared to those in the first test. In the third test, only three participants circled a different area than in the second test. Ten participants showed similar changes with pain location in pain quality in the three PSLR tests. This study revealed the effect of specific verbal instructions prior to PSLR tests. Particularly, participants could notice exact pain location. Our findings may help PT to understand pain cause and reduce patients’ stress during pain assessment in clinical settings.

Helplessness-like escape deficits of NIH-HS rats predict passive behavior in the forced swimming test:Relevance for the concurrent validity of rat models of depression

The genetically heterogeneous NIH-HS rat stock has been characterized by its response to anxiety- and fear-inducing situations, thus leading to the conclusion that they are a rather anxious and passive coping type of rats. Taking advantage of these profiles, and knowing that they show very poor performance in the two-way active (shuttle box) escape/avoidance task, we have tested NIH-HS rats (n = 80) in the forced swimming test (FST) as well as we have studied escape response deficits (i.e. response failures) of the same animals in the two-way shuttle box task. They were also tested for anxiety in the elevated zero-maze. The goal of such a study was that of investigating whether there are associations or relationships among helplessness-like or passive coping responses between both models of depression, i.e. the FST and the helplessness-like escape deficits in the shuttle box task. The results for the first time show associations among responses from both depression models and that selecting rats for displaying extreme (active or passive) responses in one of the models predict in a coherent manner (according to the hypothesis) their behaviour in the other model. These findings are discussed in the context of the concurrent validity of both models of depression as well as concerning the possible relevance of NIH-HS rats as a tool for future studies on this field.

Experimental Study of Acoustic Noise Correlation Technique for Passive Monitoring of Rails

The work presented in this paper aims at investigating the ability of acoustic noise correlation technique for railway infrastructure health monitoring. The principle of this technique is based on impulse responses reconstruction by correlation of random noise propagated in the medium. Since wheel-rail interaction constitutes a source of such noise, correlation technique could be convenient for detection of rail defects using only passive sensors. Experiments have been carried out on a 2 m-long rail sample. Acoustic noise is generated in the sample at several positions. Direct comparison between an active emission-reception response and the estimated noise correlation function has confirmed the validity of the equivalence relation between them. The quality of the reconstruction is shown to be strongly related to the spatial distribution of the noise sources. High sensitivity of the noise-correlation functions to a local defect on the rail is also demonstrated. However, interpretation of the defect signature is more ambiguous than when using classical active responses. Application of a spatiotemporal Fourier transform on data recorded with variable sensor-defect distances has allowed overcoming this ambiguity.

Application of computational fluid dynamics in design of viscous dampers-CFD modeling and full-scale dynamic testing

Computational fluid dynamics(CFD)provides a powerful tool for investigating complicated fluid flows.This paper aims to study the applicability of CFD in the preliminary design of linear and nonlinear fluid viscous dampers.Two fluid viscous dampers were designed based on CFD models.The first device was a linear viscous damper with straight orifices.The second was a nonlinear viscous damper containing a one-way pressure-responsive valve inside its orifices.Both dampers were detailed based on CFD simulations,and their internal fluid flows were investigated.Full-scale specimens of both dampers were manufactured and tested under dynamic loads.According to the tests results,both dampers demonstrate stable cyclic behaviors,and as expected,the nonlinear damper generally tends to dissipate more energy compared to its linear counterpart.Good compatibility was achieved between the experimentally measured damper force-velocity curves and those estimated from CFD analyses.Using a thermography camera,a rise in temperature of the dampers was measured during the tests.It was found that output force of the manufactured devices was virtually independent of temperature even during long duration loadings.Accordingly,temperature dependence can be ignored in CFD models,because a reliable temperature compensator mechanism was used(or intended to be used)by the damper manufacturer.

Current State of Numerical Simulations and Testing for the Blast and Impact Protection of the Build Civil Engineering Infrastructure

The identification of the critical infrastructure has shown that the build civil engineering infrastructure is almost involved everywhere, even with the IT-infrastructure. Therefore, the passive safety of structures is demanded. Security associations have analysed that most assaults came along with explosion and impact scenarios, which amount in 80% of assaults. Consequently, these are the extraordinary loads the structures have to be planned and designed for. To carry out such an engineering job, the engineer has to be educated in multiple disciplines as physics, material science , continuum mechanics, numerical mechanics, testing, structural engineering and related specific fields as wave propagation etc. In this paper we will concentrate on the subjects of numerical simulation and testing.

侧部注浆对已建盾构隧道受荷变形影响试验研究

采用侧部注浆法整治盾构隧道横椭圆变形超限过程中,盾构隧道周围附加土压力及隧道变形特性暂不明晰。通过几何相似比为1∶10的缩尺寸模型试验开展了侧部注浆对已建盾构隧道的影响试验研究,试验结果分析表明:在注浆挤压作用下,将导致隧道周围的土压力在注浆点处局部增大,两边有一定程度的减小,产生了明显的水平被动土拱现象;在注浆附加荷载影响下,模型盾构隧道在注浆点附近发生了竖椭圆变形,而在离注浆点较远处则发生了横椭圆变形,且隧道发生了反弯现象;注浆过程中发生了“渗透→挤密→劈裂”扩散模式与“挤密→劈裂→渗透”扩散模式,并阐明了两种浆液扩散模式的扩散机制;隧道外壁附加荷载主要由浆液通过渗透扩散与劈裂扩散的浆液压力所形成,同时浆液挤压土体变形对隧道周围的浆液也将形成一定的挤压荷载。

示范快堆非能动棒驱动机构可靠性指标验证研究

示范快堆非能动棒驱动机构是非能动停堆机构的组成部分之一,用于在反应堆启动时提升非能动棒。非能动棒驱动机构的可靠性验证采用定数试验的方法。由于相关标准在适应性方面存在部分问题,基于相关概率统计理论,推导得出非能动棒驱动机构可靠性验证的统计试验方案,并且制定适宜的试验剖面。试验统计结果满足验证方案的接收准则,设备可靠性水平高于指标要求的置信度为70.3%。

无源多通道星载光纤滑环可靠性设计与试验

目前关于光纤滑环(FORJ)在空间应用领域的文献较少,设计了一种无源多通道星载FORJ,首先分析了该设备在空间环境中运行时可能面临的问题及挑战,然后基于成熟的技术方案进行了针对性的可靠性设计,最后对设计的星载FORJ进行了试验验证。试验结果表明,所提的无源多通道星载FORJ达到了空间应用要求。

攻防实战视角下医院进攻性网络安全防御体系的构建与应用

目的为解决医疗结构网络安全工作无法量化、被动防御体系、专业技术人员短缺的现状,探索构建医院进攻性网络安全防御体系。方法通过搭建态势感知平台,联合互联网暴露面管理、开放端口管理、渗透测试、网络区域隔离、终端威胁检测与响应、安全培训等技术措施,构建医院进攻性网络安全防御体系。结果通过构建医院进攻性网络安全防御体系,医院网络安全事件主动发现数量和自动拦截数量均显著高于实施前(P<0.05),且平台具备良好的处理性能和稳定性。结论医院进攻性网络安全防御体系可改善目前医疗行业网络安全被动防御的现状,显著增强医院的网络安全防护能力。

被动式储能助力下肢外骨骼系统设计与仿真分析

为了达到缓解人体行走时的关节压力、减轻关节负担和辅助人体行走的目的,基于人体行走原理提出了髋膝耦合被动式储能助力外骨骼设计方案。髋膝耦合机构用于实现膝关节的离散化助力,是以髋关节运动控制膝关节助力的离合控制方法。该文运用仿真和实验验证的方法验证了该外骨骼的有效性。运用Adams对人-机模型进行联合仿真,验证外骨骼对人体助力的理论效果。在实际穿戴实验中,通过对比是否穿戴外骨骼人体运动时的能耗来验证外骨骼的真实有效性。对比仿真与穿戴实验数据证明该外骨骼能够降低12%~13%的人体运动能耗。

深厚软土深基坑被动区土体加固机制

周边环境复杂地区的软土深基坑对变形控制的要求极高,目前基坑支护主要遵循“强桩强撑”的设计思路,针对坑底以下存在深厚软土地层的情况,对基坑内侧被动区软土进行加固,能改善土体物理力学性能,有效约束基坑开挖变形。建立4种深厚软土地层基坑开挖模型,通过将离心模型试验的实际监测结果与Plaxis3D岩土有限元软件建立的等比例三维数值模型模拟结果相互验证,研究支护桩端在软土中的深基坑变形破坏模式和被动区加固效果。结果表明:在被动区软土未加固的情况下,支护桩端在软土中的基坑发生整体失稳破坏,支护桩进入硬土后的嵌固作用对基坑变形控制非常有利,在被动区设置裙边矩形加固,基坑变形显著减小;随着加固体深度、宽度的增加,基坑各项变形值均呈减小趋势,到一定值后变化不明显,加固深度、加固宽度的有效范围分别为0.4H~0.6H、0.6H~1.0H;加固体尺寸变化对地表沉降的影响最大,其次为支护桩水平位移、基底隆起。

基于离心模型试验的软土基坑被动区加固

深厚软土地区深基坑内侧被动区土体抗力明显不足,开挖容易诱发较大的围护结构变形和基坑整体失稳,被动区软土加固能有效改善软土力学性能,约束基坑围护结构变形。为探究软土深基坑被动区加固的作用效果,结合离心模型试验和数值模拟技术,对被动区软土加固基坑的变形与受力特性进行了分析。结果表明:深基坑被动区软土加固能够抑制基坑围护结构出现较大的变形,且提升了被动区土体的抗力;随着被动区加固体加固宽度或加固深度的增加,基坑支护桩水平位移、主动区地表沉降值、被动区基底隆起值均呈减小的趋势;被动区加固宽度和加固深度存在合理的区间范围,当加固深度为0.5~0.6倍开挖深度、加固宽度为0.6倍开挖深度时,基坑变形控制程度较好,加固体加固深度变化对基坑变形响应更敏感,因此在软土地区深基坑被动区加固时,应优先考虑加固体加固深度对基坑变形控制的影响。

锌铝镁板表面硫脲改性水性丙烯酸树脂-有机硅烷复合钝化膜的耐蚀性能研究

为探究硫脲改性水性丙烯酸树脂-有机硅烷复合钝化膜对锌铝镁镀层耐蚀性能的影响,以水性丙烯酸树脂-有机硅烷作为主要成膜物质,添加不同含量的硫脲复配出无铬钝化液,对锌铝镁镀层进行复合钝化。采用Nano ZS90型纳米粒度仪测试硫脲的粒径大小,采用Nicolet 6700型傅立叶红外光谱仪(FTIR)测试硫脲的结构,通过全浸试验、电化学测试和中性盐雾试验,分析复合钝化膜的耐蚀性能,并探究了硫脲含量对复合钝化膜腐蚀速率的影响。结果表明:硫脲对锌铝镁镀层的耐蚀性起到了缓蚀作用,但是硫脲含量过多,会使钝化膜的缓蚀性下降,对比了3种不同硫脲添加量,当钝化液中硫脲的质量分数为0.5%时,锌铝镁镀层的耐蚀性最优。硫脲与水性丙烯树脂-有机硅烷发生了交联作用,腐蚀后与金属形成配合物,形成了致密的网状结构,提高了膜层的致密性,从而降低了膜层的腐蚀速率。

输电塔圆钢管的涡激振动气动控制研究

作为一种力学性能卓越的输电塔类型,钢管塔在工程中应用广泛。然而,当钢管塔材长细比较大且趋于水平布置时,钢管杆在风速较小时容易发生涡激振动。在长期运行过程中,这种持续反复的振动可能造成钢管塔构件的疲劳破坏,塔体结构一旦发生破坏,将直接威胁到电网的稳定运行。针对该问题开展研究,采用大尺寸真型钢管杆件,通过风洞试验分别研究了螺旋形扰流线和被动吹气套环2种涡激振动气动控制措施。分析不同螺旋线数量、螺距和不同孔厚、孔型对涡振控制效果的影响规律。研究结果表明:单螺旋线控制效果一般,三螺旋线最多可以削减97.7%的涡振,套环控制最多可以削减75.5%的涡振。文中使用足尺模型以满足雷诺数需求,实现更接近输电塔钢管真实环境的研究,为实际工程中钢管涡激振动抑制提供参考和借鉴。

加载速率对碳纤维布被动约束煤能量演化的影响

为探究加载速率对碳纤维(CFRP)布被动约束煤能量演化特征的影响规律,利用SAM-2000型电液伺服岩石力学试验系统,开展了不同加载速率下CFRP被动约束煤样单轴压缩试验。研究结果表明:CFRP被动约束煤样总能量随轴变形增加呈以“下凹状”渐增至某平稳斜率,单层工况下平稳斜率均小于双层的,且前者斜率增速大于后者的,但最大加载速率下其平稳斜率为断崖式骤增;峰值点总能量及其增长比均随CFRP层数的增加而增大,且CFRP层数对煤峰值点总能量及其增长比影响的显著性明显优于加载速率的,获得了不同速率下峰值点总能量增长比的函数演化规律,并建立了兼顾考虑加载速率与CFRP层数的响应曲面;当加载速率最小(大)时,峰值点耗散能率增长比均随CFRP层数增加而减小,且最大加载速率下其值约为加载速率最小时的6.03~8.87倍,在速度1.67×10^(-3)~1.67×10^(-2)mm/s内,峰值点耗散能率及其增长比均随层数增加而增大,获得了不同加载速率下峰值点耗散能率增长比的函数演化规律,并建立了兼顾考虑速率与CFRP层数的响应曲面;被动约束煤样弹性能耗比随轴变形增加呈现先快速陡降过渡为缓降至稳态拐点后又从缓增过渡为快速陡增的特点,呈“鱼钩”状,在峰值附近的弹性能耗比出现连续形似阶梯状突变,表明裂隙在快速发育。

3.5%NaCl环境中S32205双相不锈钢与N09925镍基合金的钝化膜特征及耐蚀性

采用莫特肖特基(Mott-Schottky)分析方法、电化学阻抗谱(EIS)和X射线光电子能谱(XPS)等,对比研究了S32205双相不锈钢和N09925镍基合金在3.5%NaCl溶液中的钝化膜特征和耐蚀性。结果表明:N09925镍基合金表面钝化膜的缺陷密度低于S32205双相不锈钢,两种材料表面的钝化膜中均存在Fe和Cr元素富集,主要成分为Cr和Fe的氧化物和氢氧化物;S32205双相不锈钢表面钝化膜中含有少量金属Ni,N09925镍基合金表面钝化膜中Ni含量较高,还含有Ni的氧化物和氢氧化物;N09925镍基合金的阻抗值更高,其膜层电阻和电荷传递电阻均高于S32205双相不锈钢,N09925镍基合金表面钝化膜的保护性高于S32205双相不锈钢。