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Using a Modified Harmonic Wavelet Transform to Characterize Mechanical Shock 用改进谐波小波变换表征机械冲击
Journal of the IEST Pub Date : 2011-10-24 DOI: 10.17764/JIET.54.2.J187251G263N25PV
D. Smallwood
{"title":"Using a Modified Harmonic Wavelet Transform to Characterize Mechanical Shock","authors":"D. Smallwood","doi":"10.17764/JIET.54.2.J187251G263N25PV","DOIUrl":"https://doi.org/10.17764/JIET.54.2.J187251G263N25PV","url":null,"abstract":"A modified harmonic wavelet transform is used to estimate a time varying spectral density. The resolution of the estimate has an approximate constant time-frequency product. The estimation error is directly related to this time-frequency product. Unwanted cross product terms are effectively minimized. Several examples are given: White random, two sine waves, chirps, impulses, sums of exponentially decaying sinusoids, and a pyroshock. It is also shown how realizations can be generated from the modified harmonic wavelet transform estimate of the time varying spectral density.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805585","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
A 6-DOF Vibration Specification Development Methodology 一种六自由度振动规范开发方法
Journal of the IEST Pub Date : 2011-10-24 DOI: 10.17764/JIET.54.2.J6TR2R787846931N
M. Hale
{"title":"A 6-DOF Vibration Specification Development Methodology","authors":"M. Hale","doi":"10.17764/JIET.54.2.J6TR2R787846931N","DOIUrl":"https://doi.org/10.17764/JIET.54.2.J6TR2R787846931N","url":null,"abstract":"Multiple degree of freedom (MDOF) excitation systems and MDOF vibration control systems continue to improve, and are now standard equipment in many dynamic test laboratories. This paper concentrates on the often overlooked process of determination of an input specification for such MDOF systems. A pair of generalized six-degree-of-freedom (6-DOF) vibration specification development (VSD) techniques are proposed, discussed, and illustrated through an example.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67806716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 5
Sampling Plan for Cleanroom Classification with Respect to Airborne Particles 洁净室分级的空气悬浮粒子取样方案
Journal of the IEST Pub Date : 2011-01-07 DOI: 10.17764/JIET.54.1.X034466930341406
N. Hartvig, G. Farquharson, R. Mielke, M. Varney, Mike Foster
{"title":"Sampling Plan for Cleanroom Classification with Respect to Airborne Particles","authors":"N. Hartvig, G. Farquharson, R. Mielke, M. Varney, Mike Foster","doi":"10.17764/JIET.54.1.X034466930341406","DOIUrl":"https://doi.org/10.17764/JIET.54.1.X034466930341406","url":null,"abstract":"The concentration of airborne particles is a critical parameter for cleanrooms, clean zones, and controlled areas. Particle concentration must be measured at representative locations for classification and monitored routinely or continuously at critical locations during operation. Both ISO 14644-1:19991 and the new Draft International Standard (DIS) edition provide nine classes of cleanliness and specify both the number of sample locations for classification and the acceptance criterion for the data.In the 1999 version of the Standard, the minimal number of sample locations is not based on statistical principles. The acceptance criterion is based on a statistical test, but only if the number of sample locations is less than 10. Thus, classification is based on statistical methods only for a small number of locations.The revised ISO/DIS 14644-12 replaces this method with a statistical principle for selection of the sample locations. The acceptance criterion in the revised version eliminates the need for ap...","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805480","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 4
Fatigue Margins Established by Unit and Spacecraft Protoqualification Tests 由单元和航天器原型验证试验确定的疲劳裕度
Journal of the IEST Pub Date : 2010-10-25 DOI: 10.17764/JIET.53.2.Y64W73R736V8M375
E. Pierre-Louis
{"title":"Fatigue Margins Established by Unit and Spacecraft Protoqualification Tests","authors":"E. Pierre-Louis","doi":"10.17764/JIET.53.2.Y64W73R736V8M375","DOIUrl":"https://doi.org/10.17764/JIET.53.2.Y64W73R736V8M375","url":null,"abstract":"Protoqualification (PQ) testing, typically performed on the first assembled electronic units and spacecraft, establish random vibration and thermal cycling fatigue margins for subsequent builds that are only subjected to the acceptance test program (ATP). Considering the fatigue damage induced by both unit- and spacecraft-level testing, fatigue margins are calculated for equipment exposed to ATP-level testing. Probabilistic analyses are also performed to determine the relationship between the fatigue margin and the demonstrated reliability for the unit to survive the mission. Parameters such as the number of retests and the material dependent fatigue acceleration exponent are considered.Using MIL-STD-1540E,1 PQ random vibration test guidelines of three decibels (+3 dB) above the acceptance input level for 2-minute-per-axis duration, the assessment shows that the test establishes ample fatigue margin for units subjected to the less stringent ATP. The probabilistic analysis shows that the established reliab...","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Utilizing the Generalized Linear Mixed Model for Specification and Simulation of Transient Vibration Environments 利用广义线性混合模型对瞬态振动环境进行规范与仿真
Journal of the IEST Pub Date : 2010-10-25 DOI: 10.17764/JIET.53.2.Y7291022622225X3
Ronald Merritt
{"title":"Utilizing the Generalized Linear Mixed Model for Specification and Simulation of Transient Vibration Environments","authors":"Ronald Merritt","doi":"10.17764/JIET.53.2.Y7291022622225X3","DOIUrl":"https://doi.org/10.17764/JIET.53.2.Y7291022622225X3","url":null,"abstract":"Transient vibration environments are an important consideration in qualification of aircraft store components — particularly for aircraft with internal storage bays. Generally, these transient vibration environments provide high stimulus input to a store via aerodynamic forces for up to 15 seconds on numerous occasions during training. With the recent introduction of the technique of Time Waveform Replication (TWR) to laboratory testing (MIL-STD-810G Method 525), store components can be readily tested to replications of field-measured transient vibration environments. This paper demonstrates the use of the Generalized Linear Mixed Model (GLMM) on a collection of measured field responses for specification of transient vibration environments. The paper establishes a basis for moving from (1) transient vibration measured field response to (2) transient vibration stochastic specification of the measured field response to (3) laboratory simulation of transient vibration environments.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Isolation and Identification of Rubisco Extracted from Spinach Leaves 菠菜叶中Rubisco的分离与鉴定
Journal of the IEST Pub Date : 2010-10-25 DOI: 10.17764/JIET.53.2.Y3T50K754625822W
D. Weaver
{"title":"Isolation and Identification of Rubisco Extracted from Spinach Leaves","authors":"D. Weaver","doi":"10.17764/JIET.53.2.Y3T50K754625822W","DOIUrl":"https://doi.org/10.17764/JIET.53.2.Y3T50K754625822W","url":null,"abstract":"This paper evaluates a laboratory process for extracting, isolating, and identifying rubisco, an essential protein found in plant cells and an important catalyst during photosynthesis. Isolating rubisco from other proteins also found in plants requires a carefully planned series of laboratory procedures to separate the proteins on the basis of physical characteristics including solubility, electrical charge, and molecular size. In this study, ammonium sulfate precipitation was used to extract proteins from a sample of spinach leaves and to separate the proteins into two samples with different solubility characteristics. These samples were then subjected to ion exchange column chromatography using buffers with a range of salt concentrations to produce fractions with varying electrical charge characteristics. The resultant fractions were then analyzed via protein electrophoresis to determine the molecular weight of the isolated proteins, which were compared against the known molecular weight of rubisco. Fin...","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
The Clothes Truly Did Make This Man 衣服造就了这个人
Journal of the IEST Pub Date : 2010-10-25 DOI: 10.17764/JIET.53.2.Y8286660G3483QR3
H. Parsons
{"title":"The Clothes Truly Did Make This Man","authors":"H. Parsons","doi":"10.17764/JIET.53.2.Y8286660G3483QR3","DOIUrl":"https://doi.org/10.17764/JIET.53.2.Y8286660G3483QR3","url":null,"abstract":"","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67805382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Prognostics and Health Assessment Implementation for Electronic Products 电子产品的预测和健康评估实施
Journal of the IEST Pub Date : 2010-04-12 DOI: 10.17764/JIET.53.1.18763271G23N61X0
Jie Gu, M. Pecht
{"title":"Prognostics and Health Assessment Implementation for Electronic Products","authors":"Jie Gu, M. Pecht","doi":"10.17764/JIET.53.1.18763271G23N61X0","DOIUrl":"https://doi.org/10.17764/JIET.53.1.18763271G23N61X0","url":null,"abstract":"Traditional handbook-based reliability prediction methods for electronic products are inaccurate and misleading. In this paper, we will present a prognostics and health management (PHM) approach that is more suitable for reliability (remaining life) assessment for electronic products, since it considers actual operational and environmental loading conditions for individual products. The process for implementing PHM in electronics is discussed. Several examples of implementation in industry and defense are also given.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67804662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Novel Guided Head Expander Design Uses Close Coupled Inertial Masses and Hydrostatic Bearings to Minimize Cross-Axis Motion 新型导向头部膨胀器设计采用紧密耦合惯性质量和静压轴承，以尽量减少跨轴运动
Journal of the IEST Pub Date : 2010-04-12 DOI: 10.17764/JIET.53.1.18M5H0U285845U84
Doug Lund, R. Crawford
{"title":"Novel Guided Head Expander Design Uses Close Coupled Inertial Masses and Hydrostatic Bearings to Minimize Cross-Axis Motion","authors":"Doug Lund, R. Crawford","doi":"10.17764/JIET.53.1.18M5H0U285845U84","DOIUrl":"https://doi.org/10.17764/JIET.53.1.18M5H0U285845U84","url":null,"abstract":"When vertical vibration testing of large test articles is required, it is common to install a head expander on the armature of a shaker. Larger test articles often have a center of gravity relatively far above the mounting surface. When combined with the armature and head expander, these test articles may exhibit multiple structural resonances within the desired test band that do not exist in the intended application. These test configuration-driven characteristics are likely to create unwanted cross-axis excitation during a vibration test.The difficulty in controlling unwanted cross-axis motion usually increases when testing large items. Excessive cross-axis motion can \"over-test\" the test item, creating the risk of damaging the test item, or can limit the input in the test axis, thus jeopardizing a successful test.Orbital Sciences commissioned the design of a guided head expander system that greatly reduces the cross-axis motion at the test article mounting surface of the head expander. The design submi...","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67804742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Facts and Fiction in Cleanroom Metrology 洁净室计量中的事实与虚构
Journal of the IEST Pub Date : 2010-04-12 DOI: 10.17764/JIET.53.1.1347KX8001212686
L. Gail, D. Stanischewski
{"title":"Facts and Fiction in Cleanroom Metrology","authors":"L. Gail, D. Stanischewski","doi":"10.17764/JIET.53.1.1347KX8001212686","DOIUrl":"https://doi.org/10.17764/JIET.53.1.1347KX8001212686","url":null,"abstract":"This article discusses a number of cleanroom qualification parameters in terms of their proper specification. A critical analysis reveals that the useful operating range of some parameters is not appropriately considered by some early standards and guidelines, which are still used by regulatory authorities (the US Food and Drug Administration (FDA) and the European Union (EU)) and industry professionals. In practice, the windows of safely controlled cleanroom operation prove to be considerably larger than anticipated by existing regulations, especially with regard to unidirectional airflow velocity, pressure difference, and other parameters. Many measuring techniques, such as installed HEPA filter integrity testing and recovery time testing, are also regulated more strictly than necessary. Modern cleanroom testing requires more carefully defined targets and more flexibility in using advanced test procedures.","PeriodicalId":35935,"journal":{"name":"Journal of the IEST","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67804697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
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