Designing of multiple deferred state sampling plan for generalized inverted exponential distribution

In this article, we propose a sampling plan called a multiple deferred state sampling plan for sentencing a lot based on the information of current and successive lot samples. Based on this sampling plan, the median life of the product is assured based on a time-truncated life test where the lifetime of the product follows the generalized inverted exponential distribution. The quality of the product is measured by its median life. The optimal parameters of the proposed plan are obtained by using the approach of two points on the operating characteristic curve. Tables are also constructed for determining the optimal parameters with various shape parameters. The implementation of the proposed plan is illustrated with examples. The performance of the proposed plan is compared with the performance of existing sampling plans under the generalized inverted exponential distribution.     

Determination of optimal quick switching system with varying sample size for assuring mean life under Weibull distribution

Conventional sampling plans are applied to dispose an individual lot or isolated lot that requires a large sample size. Consequently, the inspection time and cost needed to make a decision under conventional plans are high. In order to reduce the sample size and to inspect the series of lots with minimum cost and time, special purpose plans are utilized. In this article, we propose one of the special purpose plans, namely, a quick switching sampling system that is also known as a two-plan sampling system. Through this sampling system, the Weibull-distributed mean life of the product is ensured based on time-truncated life tests. The proposed system is designed with the intention of minimizing the average sample number using two points on the operating characteristic curve approach. The optimal parameters of the proposed system are determined for different combinations of producer’s risk and consumer’s risk. Implementation of the proposed system is also explained and the performance of the proposed system is compared with other existing plans. In addition, the effects of misspecification of shape parameters on optimal parameters and the probability of acceptance are discussed.     

Designing of two mixed variable lot-size sampling plans using repetitive sampling and resampling based on the process capability index

In this article, we propose two types mixed variable lot-size sampling plans using the process capability index. The first one is the mixed variable lot-size repetitive sampling plan and the other is the mixed variable lot-size sampling plan for resubmitted lots. The design methodology of the proposed mixed sampling plans for symmetric and asymmetric fraction nonconforming cases is presented. Tables are constructed to determine the optimal parameters for practical applications. The industrial applications of the proposed mixed sampling plans are explained with illustrative examples. Comparison of the proposed sampling plans with other existing sampling plans is also made.     

Determination of multiple dependent state repetitive group sampling plan based on the process capability index

Abstract

In this article, we propose a sampling plan called a multiple dependent state repetitive group sampling plan for variable inspection based on the process capability index C_pk. The proposed sampling plan is applicable for the inspection of normally distributed quality characteristics when both mean and variance are assumed to be unknown. This new plan under variable inspection will be very useful particularly in compliance testing. Tables are also constructed for the determination of optimal parameters for easy selection and implementation of the plan. The optimal parameters can be determined by using the approach of two points on the operating characteristic curve. Symmetric and asymmetric cases based on the fraction nonconforming by the lower and the upper specification limits are also considered. Advantages of the proposed plan are also discussed. It is also shown that the proposed plan outperforms other existing sampling plans under variable inspection.     

如何提高尿素溶液分析的质量控制

针对提高尿素溶液分析的质量控制问题，从样品的采集、仪器的使用要求、操作技能的标准化等几方面作了细致的分析，认为在抓好上述环节同时，还要建立健全各项管理制度和数据资料的监督、审核规定，是确保分析数据准确的重要步骤之一。     

电镀产品质量的抽样检验- GB/T 12609新版标准的应用

结合GB／T1 2609新版标准的内容,介绍了电镀产品的抽样检验程序、检验的实施以及检验后的处置。对新标准中检验批和批量,缺陷和不合格品类型,批质量水平 的表示。接收质量限,检验水平等指标进行了解释。重点阐述了抽样方案的确定方法和抽样方式的选择。同时,深入讨论了关于孤立批和连续批的理解和应用。     

洗中煤产品生产采煤初探

通过分析晋阳选煤厂的生产实际,对洗中煤产品的生产采样问题进行探讨,达到控制洗中煤产品质量的目的.     

煤炭采制样过程中误差来源与分析

煤质分析中80%误差来源于采样,而16%来源于制样,因此采取有代表性煤样,并将其制成无偏差的分析煤样,是煤质分析中取得可靠数据的重要环节。通过对煤炭采制样过程中部分误差来源进行分析,并通过数据进行比较,提出相应的解决方案,以减少煤质分析过程中的误差和纠纷。     

新型全柱状采样器研究与推广应用

由于煤炭是大宗产品,动力用煤煤量较大,供销频繁。电煤紧张时,煤炭供需双方质量纠纷不断,现行机械化采样器是按照标准煤炭产品设计的,在贵州省使用时存在很大的局限性,极不适应煤炭市场复杂的质量状况。企业使用中存在着很多问题,分层装车、不同品质的煤混装等造成购煤企业不能评价煤炭的真实质量,热值虚高,经济损失较大。根据现行机械化采样器存在的问题,提出了采用全柱状、全深度、全断面、全方位采取子样,子样量大且全部破碎缩分,解决了物料不均匀情况下的采制样难题,检验结果取得较好的准确性。     

Nitrate in upper groundwater on farms under tillage as affected by fertilizer use,soil type and groundwater table

Indicators are needed to check whether policies on protection of groundwater are effective and if regulations are complied with. We evaluated various indicators at different scales, both in space and in time, and at different degrees of complexity. Groundwater was sampled on 34 arable farms for 3 years. Nitrate concentration in upper groundwater was low on clay soil. On sandy soil, peat layers reduced the nitrate concentration with about 80 mg/l on average. Sandy soils with high groundwater tables had nitrate concentrations that were less than half of those at sandy soils with low groundwater tables. The relationship between different fertilization variables and nitrate in groundwater was investigated for sandy soils without peat layers. N surplus poorly correlated with nitrate concentrations in groundwater when individual sampling points were studied, but clearly increased when data were averaged at the farm level. Soil mineral nitrogen correlated best with nitrate concentrations in groundwater. The relationships show that especially on well drained soil drastic measures will be inevitable to reach good water quality.     

锅炉燃烧的智能仪表控制

针对工业使用燃油锅炉的燃烧系统进行研究，利用ＫＭＭ仪表，采用前馈控制系统，以提高锅炉燃烧效率。并绘出组态图和各类数据表，方便编程。     

Development of a PM 10/PM 2.5 Cascade Impactor and In-Stack Measurements

Combustion and industrial processes are an important source of particles. Due to the new PM 10 and PM 2.5 standards for ambient air quality, a sampling system for PM 10/PM 2.5 in-stack measurements was designed and calibrated. In this new system, the exhaust gas is isokinetically sucked into a two stage impactor through the inlet of a plane filter device and the aerosol is fractionated in the particle size classes >10 w m, 10-2.5 w m, and <2.5 w m. Due to a relatively high volume flow (ca. 3.2 m 3 /h, depending on exhaust gas conditions), sampling times are kept short, e.g., 30 min for dust concentrations of 10 mg/m 3 . The impactor was calibrated in the laboratory and then operated at various industrial plants. Parallel measurements with identical devices showed average standard deviations of 3.1% (PM 10) and 3.4% (PM 2.5). Measurements of the cascade impactor together with the plane filter device gave plausible results and average PMx/TSP ratios of 0.49 (PM 2.5/TSP) and 0.78 (PM 10/TSP), showing a large variability for different processes. Elemental analysis using total-reflection X-ray fluorescence spectrometry, together with the size-fractionated sampling, proved to give characteristic patterns of the emitted aerosols, which can be used for a subsequent fingerprint modelling for source apportionment of ambient air pollution.     

基于数据库规则的农村生活污水水质监测智能管理系统的设计

根据对农村生活污水水质监测现状问题的分析,提出适用于全国的以行政区划代码为基本结构的农污站点编码规则和有助于实验室样品管理和溯源的农污采样编号规则;在此数据库规则基础上,对农村生活污水水质监测智能管理系统进行设计,依托农污站点数据库和农污水质监测数据库,构建基础信息模块、工程信息模块、工艺信息模块、现场采样模块和水质信息模块功能结构,实现各场景应用和综合展示,为全面摸清农村生活污水治理现状提供信息化和智能化手段。     

ESTIMATION OF THE MULTIVARIATE AUTOREGRESSIVE MOVING AVERAGE HAVING PARAMETER RESTRICTIONS AND AN APPLICATION TO ROTATIONAL SAMPLING

Abstract. The vector autoregressive moving average model with nonlinear parametric restrictions is considered. A simple and easy-to-compute Newton-Raphson estimator is proposed that approximates the restricted maximum likelihood estimator which takes full advantage of the information contained in the restrictions. In the case when there are no parametric restrictions, our Newton-Raphson estimator is equivalent to the estimator proposed by Reinsel et al. (Maximum likelihood estimators in the multivariate autoregressive moving-average model from a generalized least squares view point. J. Time Ser. Anal. 13 (1992), 133–45). The Newton-Raphson estimation procedure also extends to the vector ARMAX model. Application of our Newton-Raphson estimation method in rotational sampling problems is discussed. Simulation results are presented for two different restricted models to illustrate the estimation procedure and compare its performance with that of two alternative procedures that ignore the parametric restrictions.     

Distributed model predictive control based on adaptive sampling mechanism

In this work, an adaptive sampling control strategy for distributed predictive control is proposed. According to the proposed method, the sampling rate of each subsystem of the accused object is determined based on the periodic detection of its dynamic behavior and calculations made using a correlation function. Then, the optimal sampling interval within the period is obtained and sent to the corresponding sub-prediction controller, and the sampling interval of the controller is changed accordingly before the next sampling period begins.In the nextcontrolperiod, the adaptive sampling mechanism recalculates the sampling rate of each subsystem's measurable output variable according to both the abovementioned method and the change in the dynamic behavior of the entire system, and this process is repeated. Such an adaptive sampling interval selection based on an autocorrelation function that measures dynamic behavior can dynamically optimize the selection of sampling rate according to the real-time change in the dynamic behavior of the controlled object. It can also accurately capture dynamic changes, meaning that each sub-prediction controller can more accurately calculate the optimal control quantity at the next moment, significantly improving the performance of distributed model predictive control (DMPC). A comparison demonstrates that the proposed adaptive sampling DMPC algorithm has better tracking performance than the traditional DMPC algorithm.     

统计方法在钙镁磷肥原料采样分析中的应用

采用统计方法 ,针对原料磷矿个体差异 ,解决磷矿采样的代表性。根据原料质量的波动 ,对确定的采样分析频率 ,估算其平均值与实际值的差值 ,并为严格按照配方生产 ,计算折标消耗提供可靠的计算依据     

优选采样机是保证出口煤采样精确度的关键

阐述了对出口煤采样工作的重要性,介绍了适合于中国外贸出口用的一些进口采样机的基本特性。     

The definition and assessment of mixture quality in mixtures of particulate solids

This review paper examines the research and industrial requirements for a quantitative measure of the quality of mixtures of particulate solids and the criteria by which it may be assessed.The concept of a random or stochastic mixture is discussed and the numerous indices proposed to define mixture quality statistically are examined. The additional importance of mixture structure is emphasised, particularly in relation to continuous mixing. It is concluded that three basic criteria are required to rigorously define mixture quality that can be summarised as: between-sample variance or intensity of segregation, scale of segregation or small scale structure, and long range structure.The various methods used to experimentally measure mixture quality are described and the considerable difficulties encountered are discussed, particularly in relation to industrial application. It is proposed that, whilst the theoretical background is now well established, much more work is required on the technique of data acquisition.     

芒硝法生产硫酸钾水平衡问题讨论

芒硝法生产硫酸钾是利用两段转化、一次蒸发来完成硫酸钾及副产品工业盐的生产,整个系统封闭循环.在实际生产中,进入系统的水和流出系统的水达到平衡时整个系统才能稳定运行,但是二者受产品质量的制约很难达到平衡.对水不平衡问题进行了理论分析.详细论述了水不平衡对产品质量和整个系统的影响.找出了产生水不平衡的原因,并提出解决办法,即可通过调整一转化配料点提高钾芒硝质量、加开真空结晶器和强化蒸发提高残液质量、掌握工艺水和非工艺水的加入等一系列措施,解决系统的水不平衡问题.     

MAXIMUM LIKELIHOOD ESTIMATION FOR AUTOREGRESSIVE PROCESSES DISTURBED BY A MOVING AVERAGE

Abstract. Maximum likelihood estimation for stationary autoregressive processes when the signal is subject to a moving-average sampling error is discussed. A modified maximum likelihood estimator is proposed. An algorithm for computing derivatives of the modified likelihood is suggested. Maximum likelihood estimators of the parameter vector are shown to be strongly consistent and to have a multivariate normal limiting distribution. A Monte Carlo simulation shows that the modified maximum likelihood estimator performs better than other available estimators. US current labour force data are analysed as an example.