舰船拖带安全评估的故障树方法

提出了一种从故障树分析的角度进行舰船拖带安全评估的方法。采用专家评估和模糊集理论相结合的原理得到故障树中基本事件发生的模糊概率，然后进行故障树定性和定量分析。该方法能合理和有效地预测作业系统的安全性及其薄弱环节。以断缆事件分析为例，对该安全评估方法做了概要阐述。     

拖航安全性影响因素权值的确定方法

运用重要度排序指数法对拖航安全性影响因素的权重进行评价，对变权综合决策方法在舰船拖带中的应用进行了探讨．针对舰船拖带这一多目标决策问题建立了决策模型，对于影响拖带安全的主要指标的权重给出了相应的计算方法，并通过实例对拖带方案进行了评估，为舰船拖带的最优化评定提供了有效的解决途径．     

Wind tunnel tests on slow-running vertical-axis wind-rotors

This paper summarises the results of investigations on the Savonius-type, slow-running, vertical-axis wind-rotors as well as on rotor designs of different subclasses under comparable design and test conditions. It is seen that the performance of the conventional Savonius rotor could be considerably improved upon and the best results are achieved by using two-bladed rotors with a more sophisticated sectional profile than in the conventional design. Rotors with several blades, although capable of considerably higher performance than the Savonius rotor, do not appear to be as good as those with two blades and improved sectional geometry.     

A model for errors in tests on highly reliable measuring instruments

A refinement is proposed to the mathematical model for determining the errors of tests made with the latest highly reliable measuring instruments. __________ Translated from Izmeritel’naya Tekhnika, No. 10, pp. 15–17, October, 2007.     

机翼颤振模型的结构动力学设计

介绍了围绕某型飞机机翼颤振模型的结构动力学设计所开展的研究工作，内容包括设计目标与设计参数的确定、设计模型与设计变量的选取、设计方法与优化方法、主体结构与边界条件设计等。试验结果表明，设计出的颤振模型满足预定的振动特性要求。     

The influence of structural dimensions on crack arrest

An energy balance has been used for the prediction of toughness values required to ensure arrest in double tension crack arrest tests. The analysis required calculation of the total energy that depended on the force applied to the main plate and the effective length of the structure including the test frame. Theoretical calculations indicated that the energy release rate at crack arrest was governed by both the width and the length of the structure

     

A comparison of static and dynamic hazard perception tests

Hazard perception is a vital component to safe driving and hazard perception tests (HPTs) are being used with greater frequency for driver training, assessment and licensure. In this study, we compared a dynamic HPT (Scialfa et al., 2011), which presents short video scenes to observers and a static HPT (Scialfa et al., 2012), which uses still images. Both tests require the observer to indicate the presence of a traffic conflict that would lead to a collision between the “camera” vehicle and another road user or fixed object. Young adult drivers (n = 56) completed both forms of the HPT, along with a modified version of the Driver Behavior Questionnaire ( Reason et al., 1990) and a measure of simple reaction time. Self-reported collision and moving violation data were also collected. As in previous work, both static and dynamic HPTs had good reliability. The correlation between composite static and dynamic scores was approximately .40, but was reduced to approximately .25 when simple reaction time was controlled. Both HPTs predicted lapses and errors on the Driver Behavior Questionnaire, but neither predicted self-reported collisions or moving violations. Discussion focuses on the differences in visual cues available in dynamic and static scenes and how these differences could influence decisions about potential hazards.     

Influence of relative density on granular materials behavior: DEM simulations of triaxial tests

The rheological behavior of non-cohesive soils results from the arrangement and complex geometry of the grains. Numerical models based on discrete element modeling provides an opportunity to understand these phenomena while considering the discrete elements with a similar shape to that of the grains the soil is composed of. However, dealing with realistic shapes would lead to a prohibitive calculation cost. In a macroscopic modeling approach, simplification of the discrete elements’ shape can be done as long as the model can predict experimental results. Since the intrinsic non-convex geometry property of real grains seems to play a major role on the response of the granular medium, it is thus possible to keep this geometrical feature by using cluster of spherical discrete elements, which has the advantage to reduce dramatically the computation cost. Since the porosities found experimentally could not always be obtained with the numerical model—owing to the huge difference in shape, the notion of relative density, which requires a search for minimum and maximum porosities for the model, was chosen to compare the experimental and numerical results. Comparing the numerical simulations with the experimental triaxial tests conducted with relative densities and different confining pressures shows that the model is able to predict the experimental results.     

Validation of sobriety tests for the marine environment

The objective of this project was to develop sobriety tests that can be administered in the seated position to assist water patrol officers in detecting alcohol-related impairment in boaters. Four seated sobriety tests were administered to 330 boaters to determine the tests’ usefulness in classifying boaters as having blood alcohol concentrations (BACs) below the illegal limit (BAC < .08%) or above the illegal limit (BAC ≥ .08%). Data were obtained by a team of four marine officers and two civilian observers on Lake of the Ozarks in central Missouri. The overall correct percentages, sensitivity, and specificity of the tests were consistent with what is typically reported in literature on the roadside sobriety tests. The tests’ reliability was also consistent with what is typically reported in literature on the roadside sobriety tests. Thus, the four tests may assist marine officers with assessments of alcohol-related impairment in boaters.     

模型参考自适应恒张力控制系统研究

为解决不适张力对带材供送的影响,通过放卷辊的动力学分析,建立了张力数学模型,分析了影响张力的因素。针对放卷过程中半径变小,而常规PI控制难以实现参数在线调整,提出模型参考自适应张力控制方法,建立了参考模型,采用梯度法推导了自适应率。建立了控制系统模型,并进行了仿真。结果表明,利用该方法系统可以有效的跟随半径减小调节控制器参数,保证了系统的稳定性,缩短了调节时间,减小了超调量。     

The effectiveness of the United Nations' leakproofness tests

The regulations for the packaging of dangerous goods, which are applicable world-wide for the various modes of transport, include performance tests. It is impossible to conduct laboratory tests for every environmental condition, but the tests can produce a conservative estimate of the situation during transport. This paper analyses the so-called leakproofness test as one of the design-type tests for packagings covered by the United Nations' (UN) recommendations for dangerous goods.     

Nonparametric tests and the stationarity of signal amplitude and time measurements

Nonparametric tests have been applied to the stationarity of measurements for pulse edge length measurements, with the object of determining the time taken for a stroboscopic oscilloscope to transfer from the dynamic mode to the static one. Translated from Izmeritel'naya Tekhnika, No. 11, pp. 3–6, November, 2008.     

A critical review of ultra-accelerated tests for alkali-silica reactivity

A large number of ultra-accelerated test procedures, for determining the potential alkali reactivity of aggregates, have been developed, particularly in the past 15 years. An ultra-accelerated test method is defined as one which yields results within a few days or, at most, a few weeks. A number of ultra-accelerated test methods have been adopted as ‘standard tests’, but few have been adequately evaluated. The rapid globalization of the construction industry will require the harmonization of National Standard Test Methods. The major requirement of ultra-accelerated test methods is that they should correctly predict the potential reactivity of aggregates in greater than 95% of the cases. Due to the complexity and variability in the composition and grain size of aggregates, it is improbable that a single test method will be developed which would be appropriate for evaluating all types of aggregates. Another major requirement for ultra-accelerated test methods is that the interlaboratory coefficient of variation should be low, preferably less than 12%. At present, only the NBRI accelerated mortar bar method has been subject to adequate inter-laboratory evaluation. However, a more limited inter-laboratory investigation showed that the autoclave mortar bar test also shows considerable potential, as a satisfactory ultra-accelerated test method. Further refinement of the NBRI and autoclave methods is required to improve their performance with a wide variety of aggregates.     

Fabrication experiences and performance tests of the coal-fired flow facility superconducting dipole magnet

The Argonne National Laboratory has designed, constructed and tested a large aperture superconducting MHD magnet for use in the coal-fired flow facility at Tullahoma, Tennessee. The magnet generates a peak on-axis field of 6 T in a MHD warm bore of 80 cm diameter at inlet, 100 cm diameter at outlet, and 300 cm effective length. The stored energy of the magnet is 210 MJ, the cold mass (4.2 K) is 131 metric tons and the ampere-turns, 13.7 × 10⁶. The final design of the magnet will be briefly introduced. Described in detail are the experiences of coil winding and coil assembly, the assembly of force-containment superstructure, assembly of magnet cryostat and results of magnet performance tests.     

A set of pathological tests to validate new finite elements

The finite element method entails several approximations. Hence it is essential to subject all new finite elements to an adequate set of pathological tests in order to assess their performance. Many such tests have been proposed by researchers from time to time. We present an adequate set of tests, which every new finite element should pass. A thorough account of the patch test is also included in view of its significance in the validation of new elements.     

Some notes about nonparametric tests for the equality of two populations

A new nonparametric test for the equality of two populations is proposed. The test is a generalization of the Girone-Cifarelli test (see Girone 1964, and Cifarelli 1974, 1975) which has been shown to be occasionally more powerful than other nonparametric tests, such as the Kolmogorov-Smirnov test. The test is based on a measure of dissimilarity between the sequences of ranks corresponding to the samples drawn from the two populations. The test can be adapted to verify the hypothesis of equality against one-sided and two-sided alternatives. Exact and asymptotic critical values of the test are provided. The asymptotic distribution of the test-statistic underH _o shows an interesting link with Brownian motion in [0,1].     

Responses of side impact dummies in sled tests

Sled tests were conducted at a velocity of 6.7 m/s using side impact dummies (SID, BioSID, ES-2, and WorldSIDp) and the resulting biomechanical responses were compared with responses from post mortem human subjects (PMHS). Initial impact conditions were with and without pelvic offset in combination with and without padding on the impacting wall. Impact forces, thoracic trauma index, chest compression, and viscous criteria were evaluated. The probability of injury was estimated and rates of deformation were computed for each body region. Dummy responses were not always similar in terms of trend and injury criteria when compared with PMHS tests under the same initial conditions. Response variations will be of value in improving the biofidelity characteristics of dummies for crashworthiness evaluations.     

Bird's substitute tests results and evaluation of available numerical methods

Recent bird impact tests were conducted using gelatine as a bird substitute. A recipe for the gelatine is suggested in order to use as a reference in further bird test certification procedures. Results from the tests are also given so that they can be used to validate numerical models and promote the use of numerical tools in aircraft design and certification process.     

瓦楞纸箱生产线选择优化模型

介绍了瓦楞纸箱的生产工艺过程,对影响产品成本各因素进行了分析。同时对瓦楞纸箱生产线选择进行了分析,并给出了一种瓦楞纸箱生产线选择优化的数学模型。使企业减少了资源损耗,降低生产成本,提高了企业在市场的竞争力。     

A Viscoelastic Fictitious Crack Model for the Fracture of Sea Ice

The fracture of sea ice is modeled using a viscoelastic fictitious crack(cohesive zone) model. The sea ice is modeled as a linear viscoelastic material. The fictitious crack model is implemented via the weight function method. The associated stress-separation curve can be rate dependent. The impact of assuming viscoelastic behavior in the bulk as opposed to elastic behavior is studied. Results from the model are compared to the available exact results for various test cases. The model is applied to a large scale in situ sea ice fracture test. Various implications of such applications are pointed out. This viscoelastic fictitious crack model is found to be a promising tool in investigations pertaining to the fracture of sea ice. This revised version was published online in July 2006 with corrections to the Cover Date.