Possible estimation of resilient modulus of fine-grained soils using a dynamic lightweight cone penetrometer

Resilient modulus is an important parameter to characterise the resilient behaviour of pavement materials. Resilient modulus can be determined in the laboratory from repeated load triaxial test and is defined as the ratio of deviator stress to recoverable strain. Inherently, it is a challenge to perform repeated load triaxial tests as a routine basic test due to its complicated, time-consuming and expensive procedure; hence, several empirical approaches to estimate the resilient modulus from other soil mechanical properties – California bearing ratio, unconfined compressive strength or physical properties – have been proposed. This study has investigated the application of a dynamic lightweight cone penetrometer for the estimation of the resilient modulus in the laboratory and field conditions for some Victorian fine-grained subgrade soils. The results show the possibility to estimate the resilient modulus of fine-grained soils using the dynamic lightweight penetration index at any moisture content (MC) from optimum MC to soaked conditions.     

Quality assurance in dynamic testing

An agency concerned with the quality assurance of dynamic testing has recently been established. The following paper describes the nature and structure of this agency which is known as the DTA (Dynamic Testing Agency). The aims and philosophy of the DTA are discussed and the importance of the use of reliable experimental data in structural assessment and for the verification of theoretical predictions is emphasised.     

Quality assurance technologies for vlsi manufacturing

Considering the fundamental aims of VLSI Manufacturing and objectives of the Quality Assurance and Quality Control programs, three technologies, namely Dimensional Metrology, Material Analysis, and Statistical Methods of Process Control, emerge as key to success. The bewildering array of methods, instrumentation alternatives, and process states and variables to be controlled, make Quality Assurance and control activities as complex as the VLSI manufacturing itself, and demand a long-term commitment by all management, engineering, and work force teams involved.     

呼吸机质量控制与校准

呼吸机是医疗机构必须配备和使用的高风险设备之一,呼吸机的质量控制与校准引起了医疗机构、患者、相关技术部门的重视。通过介绍呼吸机的工作原理、机器种类、工作模式、日常的保养和维护,提高广大医务工作者的理论水平和操作水平;对现有的国家标准、行业标准、校准规范的分析介绍,了解呼吸机检测的现状和特点,为开展呼吸机的检测校准提供必要的技术支持。将呼吸机纳入国家计量管理,推进呼吸机检测校准的规范化工作,建立不同呼吸机检测校准的国家量值溯源体系,规范完善医疗机构质量保障体系。     

Analysis of dynamic compressive stress induced by passing trains in permafrost subgrade along Qinghai-Tibet Railway

To investigate dynamic compressive stress characteristics and related influencing factors in the permafrost site along Qinghai-Tibet Railway (QTR), a numerical analysis was carried out using self-compiling train-rail-subgrade-site dynamic coupling program ZL-TNTLM and ZL-RNTLM, by which the effect of the vibrating load generated by passing trains on the natural permafrost table was analyzed quantitatively. The results indicate that: (1) the additional dynamic compressive stress depend directly on axle load, the vibration energy at subgrade top surface is relatively larger when vibration frequencies range from 0.5 to 10 Hz, and the dominant frequencies at the top of the natural permafrost table are confined to be less than 3 Hz; (2) the vibration-affected subgrade area is mainly limited to the oval zone of 6 m below sleepers, stress concentration phenomena occur in the vicinity of rail-supporting zone in ballast, the maximum dynamic compressive stress at the bedding superface presents a saddle-type distribution, and certain negative exponential function can be adopted to fit the attenuation relationship of the dynamic stress vs. depth; (3) the dynamic compressive stress of subgrade top surface is the largest in winter, then followed by spring and autumn, and the least in summer, while the corresponding trend is quite the opposite in the interior of subgrade; (4) the dynamic compressive stress surrounding the wide gap decreases with the rise of train speed, however vibration response tends to be stable at certain critical speed, and the critical speed decreases with depth below subgrade surface; (5) the additional dynamic stress at the natural permafrost table can be notably reduced by appropriately increasing the embankment height. The drawn conclusions can, believed by the authors, provide certain theoretical insight for the safety evaluation of QTR operation, vibratory subsidence prediction, as well as the construction of permafrost subgrade.     

Quality control results of the drift tubes for the ATLAS MDT-BIS chambers

ATLAS (A Toroidal LHC ApparatuS) is a general purpose experiment, which will start its operation at the Large Hadron Collider (LHC) at CERN in 2007. The ATLAS detector is designed to study the products of proton–proton collisions at c.m.s. energies of up to 14 TeV. Three Greek Universities have taken the responsibility to construct 112 BIS-MDT (Barrel Inner Small) chambers using 29 000 drift tubes of 170 cm length and 3 cm diameter that have been quality tested before assembly. This work describes the Quality Assurance and Quality Control (QA_QC) procedures for the drift tubes, followed at the High Energy Physics Laboratory of the National Technical University of Athens, while emphasis is given on the obtained results for the above mentioned number of tubes.     

Design of an integrated quality assurance strategy in production systems

High-quality of products is a critical issue for manufacturers to maintain their competitiveness in global markets. For this reason, more attention has been paid by operations managers and academics to the design of quality assurance strategies, acceptance sampling plans and inspection allocation problems. In the last decades, international research has studied and introduced several models and approaches to investigate these issues. The purpose of this paper is to provide a new methodology for designing and selecting correct integrated quality assurance strategies, defining cost models for acceptance policies and inspection station configurations. Generally, high-quality of items is guaranteed by avoiding defects, mainly caused by non-conforming components, resulting from instantaneous and standard infant mortality. Thus, an optimal acceptance policy is defined in order to reduce the instantaneous infant mortality defects. A closed-form equation has been introduced to determine easily and quickly the optimal percentage of checked items. Furthermore, a more convenient inspection station configuration is determined in order to minimise the expected total cost, composed of testing, inspection and penalty cost elements. The innovative concept of defect rate as an inspection time variable dependent has been introduced. The impact of different economic and survival parameters on designing inspection policies is also investigated. Finally, a real-life case study demonstrates the applicability of this methodology in real production systems and several considerations are reported about the future research, that the authors will carry out.     

Quality assurance and quality control methodologies used within the Austrian UV monitoring network

The Austrian UVB monitoring network is operational since 1997. Nine detectors for measuring erythemally weighted solar UV irradiance are distributed over Austria in order to cover the main populated areas as well as different levels of altitude. The detectors are calibrated to indicate the UV-Index, the internationally agreed unit for erythemally weighted solar UV irradiance. Calibration is carried out in the laboratory for determination of spectral sensitivity of each detector, and under the sun for absolute comparison with a well-calibrated, double-monochromator spectroradiometer. For the conversion from detector-weighted units to erythemally weighted units a lookup table is used, which is calculated using a radiative transfer model and which reflects the dependence of the conversion on the solar zenith angle and total ozone content of the atmosphere. The uncertainty of the calibration is about +/-7%, dominated by the uncertainty of the calibration lamp for the spectroradiometer (+/-4%). The long-term stability of this type of detectors has been found to be not satisfactory. Therefore, routinely every year all detectors are completely recalibrated. Variations of the calibration factors up to +/-10% are found. Thus, during routine operation, several measures take place for quality control. The measured data are compared to results of model calculations with a radiative transfer model, where clear sky and an aerosol-free atmosphere are assumed. At each site, the UV data are also compared with data from a co-located pyranometer measuring total solar irradiance. These two radiation quantities are well correlated, especially on clear days and when the ozone content is taken into account. If suspicious measurements are found for one detector in the network, a well-calibrated travelling reference detector of the same type is set up side-by-side, allowing the identification of relative differences of approximately 3%. If necessary, a recalibration is carried out. As the main aim for the Austrian UV monitoring network is the information of the public about the actual levels of UVB irradiance, the measurement results are published on-line in the Internet (http://www.uibk.ac.at/projects/uv-index). For the previous day and backwards approximately 2 years, the distribution of maximal UVB levels over Austria is shown on a regional map. Additionally, near real-time data of most of the measurement stations are presented with a delay of usually less than half-an-hour. Together with these actually measured data there is also shown the diurnal variation of the maximal expected value of the UV-Index under ideal clear conditions.     

Computational simulations of the dynamic compaction of porous media

The goal of this study was to apply and compare different computational compaction models to the dynamic compaction of porous silicon dioxide (SiO₂) powder. Three initial specific volumes were investigated in this study, V₀₀=1.3, 4 and 10 cm³/g, where the solid material specific volume is V₀=0.4545 cm³/g. Two hydrodynamic codes, KO and CTH, were used to simulate the experimental results. Two compaction models, P– and P–λ were implemented within CTH in conjunction with the Mie–Grüneisen (MG) equation of state. The snowplow (SP) compaction model was implemented within KO. In addition, the MG equation of state based on the experimentally measured Hugoniot was implemented within CTH and was compared to the data as well. One-dimensional flyer plate experiments were conducted with impact velocities ranging from 0.25 to 1.0 km/s, which corresponded to a shock incident pressure range of 0.77–2.25 GPa. The computational simulations were compared to the temporal lateral stress signatures measured with manganin gauges, placed before and after the silica powder. It was found that the MG equation of state (EOS) most accurately reproduce all of the experimental data whereas none of the compaction models accurately reproduced all of the experimental data. However, of the compaction models investigated that the P– model tended to outperform the other considered.     

运用系统工程满足测量设备的质量保证要求

文章运用系统工程的方法,将建立“满足石钢公司测量设备的质量保证要求”作为系统目标,将影响测量设备的质量保证要求的各种因素作为一个系统进行分析,找出主要原因并制订有效措施加以实施,解决企业计量管理工作不畅、不规范等问题,恢复了计量工作在企业质量管理中应有的地位及作用。     

不确定电液位置伺服系统的动态面跟踪控制

针对一类含有动态不确定性的双作用液压缸电液伺服系统跟踪控制问题,采用动态面控制方法设计了一个鲁棒自适应跟踪控制器.由于在逆推设计过程中加入了低通滤波器使得该方法不用对模型非线性进行多次微分,因而设计方法简化.所设计的自适应鲁棒控制器不仅能保证闭环系统的半全局渐近稳定,使得输出渐近跟踪期望轨迹;而且,跟踪误差可以通过控制器的设计参数加以调整.数字仿真结果表明,控制系统对给定位置的跟踪具有良好的动态特性,对系统的不确定性,具有较强的鲁棒性.     

Experimental investigation of the dynamic behavior of frozen clay from the Beiluhe subgrade along the QTR

The dynamic behavior of frozen clay obtained from the Beiluhe permafrost subgrade along the Qinghai-Tibet Railway (QTR) was investigated through cryo-dynamic triaxial experiments. The effects of several key factors, including temperature, moisture content, frequency and confining pressure on the dynamic behavior, were analyzed. It was found that a hyperbolic model could describe the dynamic behavior of the frozen clay well. The maximum dynamic shear modulus of the frozen soil decreases as the temperature rises and as the confining pressure decreases; the reference shear strain magnitude decreases as the temperature and confining pressure increase and as the moisture content decreases; the maximum damping ratio increases as the temperature, frequency and confining pressure increase and as the moisture content decreases. There exists a critical moisture content (around 18%) that maximizes the dynamic shear modulus; at the critical frequency (about 6 Hz), the dynamic shear modulus is at its maximum, and the reference shear strain magnitude and the damping ratio attenuation exponent are at their respective minima. Moreover, functions were proposed to quantitatively describe the relationship between frozen clay dynamic parameters and various influencing factors.     

信息系统的测试与质量控制

根据信息系统质量控制的目标任务,结合实际案例,对其代码级漏洞测试、功能测试、性能测试、问题定位、回归测试和文档评审的测试方法进行描述。使人们了解信息系统的测试方法,并且对信息系统的质量控制有所重视。     

The mass production and quality control of RPCs for the Daya Bay experiment

Resistive plate chambers will be used in the Daya Bay reactor neutrino experiment to help veto backgrounds created by cosmic-ray muons. The mass production of RPCs began in 2008 and by the end of 2009, 1600 RPCs (3500 m²) had been produced and tested. This paper describes the production and quality control procedures, and quality assurance using cosmic-ray testing.     

Quality assurance and quality control programme in the Personal Dosimetry Department of the Greek Atomic Energy Commission

A quality assurance (QA) and quality control (QC) programme was applied to the personal monitoring department (TLD based) of the Greek Atomic Energy Commission (GAEC). This programme was designed according to the recommendations of international bodies such as the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC), the International Atomic Energy Agency (IAEA) and the European Commission (CEC). This paper deals with the presentation of the QA/QC programme which includes administrative data and information, technical checking of the equipment, acceptance tests of new equipment and dosemeters, issuing and processing of the dosemeters, dose evaluation, record keeping and reporting, traceability and reproducibility, handling of complaints, internal reviews and external audits.     

显影液QA,QC的科学方法

本文为自动洗片机用高温快速显影液的科学管理与质量保证提供了简便、科学的检测方法,力医(?)影像质量的提高提供了可靠的保证。具有科学性、实用性、普及性。     

虚拟企业生产过程质量保证模型

虚拟企业（VE）是由多家独立公司组建起来的临时性网络,临时性特点使得它不必涉及其成员企业的内部质量管理,而只需提供必要的信息和其它的资源服务,以协调各成员企业的活动从而保证最终的产品质量。基于这样的认识,提出了一个虚拟企业生产过程质量保证模型及其运作流,用以探讨如何解决生产过程中VE产品质量保证的问题;还详细论述了该模型的各个要素。     

基于小批量多品种生产环境的统计过程质量控制研究

分析了先进制造技术环境下实施统计过程质量控制所存在的问题,给出了一种基于正态过程的改进的标准化控制图,适用于小批量多品种生产环境下对过程均值、过程方差的有效控制。     

Investigation and characterization of a control scheme for multivariate quality control

A new scheme for multivariate statistical quality control is investigated and characterized. The control scheme consists of three steps and it will identify any out-of-control samples, select the subset of variables that are out of control, and diagnose the out-of-control variables. A new control variable selection algorithm, the backward selection algorithm, and a new control variable diagnosis method, the hyperplane methods, are proposed. It is shown by simulation that the control scheme is useful in cases where the process variables are correlated and where they are uncorrelated.