特种铸造工艺方法

特种铸造相比于砂型铸造所生产的铸件,在性能、尺寸、精度上面都有所提高,本文将选取具有特色的几种特种铸造方式进行介绍,并对其铸造方法的优缺点以及适用范围等特点进行介绍。     

连续铸造工艺生产铜套的优势分析

相对于离心铸造工艺,连续铸造工艺生产铜套具有诸多优点,可降低生产成本,提高企业竞争力。     

消失模铸钢生产中常见铸造缺陷及影响因素分析

对消失模铸钢生产中常见的铸造缺陷进行了介绍，并对产生缺陷的主要影响因素进行了分析，为消失模铸造工艺更好地应用于铸钢生产中，防止铸造缺陷的出现提供参考。     

离心铸造球墨铸铁管铁水熔炼初探

生产离心铸造球墨铸铁管，需连续加速供应成分和温度均合格的高温优质铁水。本文论述了生产对铁水供应的要求及特点，分析了铁水熔炼的工艺和设备，提出了一些建设性的意见。     

高压清洗机泵体铸造工艺研究

本文介绍采用压力铸造替代挤压铸造生产高压清洗机泵体的工艺研究。实际生产结果表明，这种生产工艺不仅能保证产品质量，而且可以大幅度提高生产效率及经济效益。     

悬浮铸造技术及其应用

悬浮铸造作为一种新兴的金属凝固控制技术，在铸钢件，尤其是大型铸钢件及其它合金的大型铸件生产中获得应用，取得了令人满意的效果。本文介绍了悬浮铸造工艺的基本原理及其在国内的应用情况     

复杂薄壁铝合金零件精密铸造的工艺及生产论证

针对精密铸造复杂薄壁铝合金零件易产生的欠铸、冷隔缺陷、重点介绍改进制备型壳工艺和溶化浇注工艺的试验研究，并结合典型铸件的生产验证，提出较佳的适用于生产薄壁铝铸件的精铸工艺、以及采用该工艺获得的经济效益。     

上引法生产无氧铜杆质量缺陷形成原因浅析及预防措施

本文介绍了用上引法生产无氧铜杆的工艺特点，根据我厂生产实际，对产品质量缺陷形成的主要原因进行了分析，并提出相应的改进措施，确定了主要工艺技术参数。     

丝杠式半连续铸造机的结构改进与使用性能的提高

本文阐述了用于铜及其合金铸锭生产的丝杠式半连续铸造机存在的问题，分析了原因，提出了解决问题的方法。     

浅谈水平连铸TP2紫铜管坯的工艺制度

水平连铸TP2紫铜管是铸轧法生产优质空调管坯的第一步工艺,其产品质量的好坏对最终空调管坯起决定作用。严格地按照工艺制度进行生产是为获得质量优良、稳定的铸造管坯的前提条件,水平连铸TP2铜管工艺制度主要包括铸造温度,铸造速度、冷却强度三方面,本文将对水平连铸铜管坯铸造生产过程中的三项工艺制度进行探讨。     

Craftsman Questionnaire Sampling

Craftsman Questionnaire Sampling (CQS) was recently developed for performance measurement and productivity improvement at construction sites. CQS uses a questionnaire to collect data. It has the virtues of the Craftsman Questionnaire Survey, which provides information regarding the sources of delays, the amount of rework performed, as well as creating a participating atmosphere on site. Meanwhile, CQS imitates the sampling procedure from the Work Sampling method by randomly selecting craftsmen in the field and asking them to determine the activities involved in the immediate past. This procedure empowers the CQS to apply the theory of binominal distribution to estimate ratio delays and to maintain the advantages of relative simplicity and statistical reliability as the Work Sampling method does. CQS was tested at a large nuclear power plant site. The results indicated the feasibility and efficiency of CQS in helping construction management identify delays that could provide a base for productivity improvement.     

Crew Performance Measurement Via Activity Sampling

Three methods of measuring the performance of construction crews are described and compared. These are: (1) Work sampling; (2) group timing technique; and (3) five‐minute rating. By gathering data from a time‐lapse film, the three methods can be compared for the same operation. Work sampling is shown to provide important information about the characteristics of delays. Considerable time is lost because of waiting for materials and for instructions. The group timing technique provides production data that is very different from work sampling. It is suggested that this technique can be used to validate estimating data regarding cycle times. It is also shown how a crew balance index can be determined which will allow the manager to evaluate if the crew size is appropriate for the way the work is being performed. The five‐minute rating is shown to be a quick estimator of the delay time of a crew. It is shown that the reliability of the five‐minute rating is not as good as that of work sampling of group timing technique. Various parameters are calculated throughout, and it is suggested that over a period of time, these can be used to monitor crew performance.     

A Comparison of Sequential Sampling Models for Two-Choice Reaction Time.

The authors evaluated 4 sequential sampling models for 2-choice decisions--the Wiener diffusion, Ornstein-Uhlenbeck (OU) diffusion, accumulator, and Poisson counter models--by fitting them to the response time (RT) distributions and accuracy data from 3 experiments. Each of the models was augmented with assumptions of variability across trials in the rate of accumulation of evidence from stimuli, the values of response criteria, and the value of base RT across trials. Although there was substantial model mimicry, empirical conditions were identified under which the models make discriminably different predictions. The best accounts of the data were provided by the Wiener diffusion model, the OU model with small-to-moderate decay, and the accumulator model with long-tailed (exponential) distributions of criteria, although the last was unable to produce error RTs shorter than correct RTs. The relationship between these models and 3 recent, neurally inspired models was also examined. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

精煤中测定粘结指数试样的制样

利用现有条件，通过试验选择了烘样温度，用GB474规定的制样设备密封式粉碎机对测定粘结指数的试样进行制样，试样粒度完全能控制达到GB／T5447—1997的要求，以试样主样、副样结果进行对比，所得分析结果基本一致。     

A356.2铸造铝合金生产中Si偏析的影响

论述了铸造铝合金生产中不同时间和状态下采样对Si偏析的影响及Si偏析对产品的影响,并应用于指导生产实际。     

Work Sampling Can Predict Unit Rate Productivity

Various methods are employed to measure labor utilization during power plant construction, one of which is work sampling. Work sampling attempts to evaluate how the work force spends its time at work. This provides timely information to management in order to determine whether corrective action or detailed study is needed to achieve a higher degree of efficiency. However, the effectiveness of work sampling in demonstrating true labor performance has not been statistically verified using data collected at construction sites. This study collects 45 work sampling data points from 11 nuclear power projects and 4 fossil fuel power projects. the relationship between work sampling and productivity has been strongly supported by this statistical analysis. This study also verifies that work sampling is a good labor productivity indicator as well as a useful predictor in a productivity projection model.     

浸出过程自动取样技术研究

基于流体力学建模和工艺参数数据验证的方法,研究了浸出槽取样代表性问题,并设计了自动取样装置,成功开发了矿浆提升和过滤装置,为下一步离子浓度在线检测奠定基础。     

在线式厚卷板取样机的研制

根据目前高钢级板卷的生产状况,结合API取样标准要求,设计出一套在线式厚板取样机,能显著提高API要求取样速度,满足快速在线生产检验的要求.     

Sampling lesbian, gay, and bisexual populations.

Sampling has been the single most influential component of conducting research with lesbian, gay, and bisexual (LGB) populations. Poor sampling designs can result in biased results that will mislead other researchers, policymakers, and practitioners. Investigators wishing to study LGB populations must therefore devote significant energy and resources to choosing a sampling approach and executing the sampling plan. The authors describe probability and nonprobability sampling methods used in LGB populations and critically discuss the advantages and disadvantages of the sampling methods they review. The authors conclude that no single sampling methodology is correct or incorrect for use in LGB populations; rather, researchers must evaluate advantages and disadvantages of each sampling methodology in the context of the specific research question and the research design. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sampling problems in studies of writing style.

Most current popular methods of reading-material analysis use "cluster" sampling—sampling by sentences. In this study, such sampling is compared with simple random sampling of individual words. No differences were found in the proportions of the various parts of speech, but the clustered sample "significantly over-estimated the percentage of 'short' words, 'structural' words, and 'easy' words. It is suggested that the structure of the sentence… has imposed an orderliness that has biased the clustered sample." (PsycINFO Database Record (c) 2010 APA, all rights reserved)