bluuebunny/crossref_metadata_2025 huggingface dataset:
Protocol for Use with Standard Insert Libraries (370-420 bp) (NEB#E7120) v1
Authors: England Biolabs New
Published: November 2020

This protocol details how to construct DNA libraries from start to finish using NEBNext reagents. The corresponding NEB manual is here: https://www.neb.com/-/media/nebus/files/manuals/manuale7120.pdf and this protocol relates to section 1. Overview The Enzymatic Methyl-seq kit (EM-seq) for Illumina contains all the components needed to make libraries that are enzymatically modified to detect 5-methylcytosines (5mC) and 5-hydroxymethylcytosines (5hmC). Figure 1 is an overview of the EM-seq workflow. Firstly, a library is made by ligating EM-seq adaptor to sheared end repaired/dA-tailed genomic DNA. This is followed by two sets of enzymatic conversion steps to differentiate cytosines from 5mC and 5hmC. Finally, libraries are PCR amplified before sequencing. Figure 2 shows a comparison of the sodium bisulfite and EM-seq methods. Sodium bisulfite treatment of DNA results in the deamination of cytosines into uracils, however the modified forms of cytosine (5mC and 5hmC) are not deaminated. Therefore, the preference of bisulfite to chemically deaminate cytosines enables the methylation status of cytosines to be determined. When bisulfite treated DNA is PCR amplified, uracils are replaced by thymines and the 5mC/5hmC are replaced by cytosines. Once sequenced, unmethylated cytosines are represented by thymines and 5mC and 5hmC are represented by cytosines. By comparing sequences to non-converted genomes the appropriate methylation status can be assessed. Enzymatic Methyl-seq is a two step enzymatic conversion process to detect modified cytosines. The first step uses TET2 and an oxidation enhancer to protect modified cytosines from downstream deamination. TET2 enzymatically oxidizes 5mC and 5hmC through a cascade reaction into 5-carboxycytosine [5-methylcytosine (5mC) Þ5-hydroxymethylcytosine (5hmC) Þ 5-formylcytosine (5fC) Þ 5- carboxycytosine (5caC)]. This protects 5mC and 5hmC from deamination. 5hmC can also be protected from deamination by glucosylation to form 5ghmc using the oxidation enhancer. The second enzymatic step uses APOBEC to deaminate C but does not convert 5caC and 5ghmC. The resulting converted sequence can be analyzed like bisulfite-treated DNA. Typical aligners used to analyze data include but are not limited to Bismark and BWAMeth. The workflow described in the NEBNext Enzymatic Methyl-seq Kit is user-friendly and enables methylation detection from inputs ranging between 10 ng–200 ng. EM-seq converted DNA is more intact than bisulfite-converted DNA, resulting in libraries with longer sequencing reads, reduced GC bias and more even genome coverage. Each kit component must pass rigorous quality control standards, and for each new lot the entire set of reagents is functionally validated together by construction of indexed libraries and sequenced on an Illumina sequencing platform. For larger volume requirements, customized and bulk packaging is available by purchasing through the Custom Solutions department at NEB. Please contact Custom@neb.com for further information.
15-minute DNA extraction from beetle legs for PCR barcoding v1
Authors: Mayers Chase
Published: November 2020

This method allows for quick extraction of DNA from beetle specimens for routine PCR amplification of barcoding genes such as COI (cytochrome oxidase subunit 1) for beetle ID. It is likely to also be effective for other high-copy genes such as other mitochondrial genes or ribosomal genes. It may not yield enough DNA to amplify large fragments or low-copy genes, and is certainly not appropriate for next-generation sequencing. However, for quick ID of beetle vouchers (for example, for beetles from which fungal cultures were isolated in a mycological study) it's hard to beat a ~15 minute DNA extraction. This protocol is part of the Bark Beetle Mycobiome (BBM) Research Coordination Network. For more information on the BBM international network: Hulcr J, Barnes I, De Beer ZW, Duong TA, Gazis R, Johnson AJ, Jusino MA, Kasson MT, Li Y, Lynch S, Mayers C, Musvuugwa T, Roets F, Seltmann KC, Six D, Vanderpool D, & Villari C. 2020. Bark beetle mycobiome: collaboratively defined research priorities on a widespread insect-fungus symbiosis. Symbiosis 81: 101–113 https://doi.org/10.1007/s13199-020-00686-9.
Fungal Plate Photography v1
Authors: Bateman Craig
Published: November 2020

This protocol describes how to photograph fungal plates. This protocol is part of the Bark Beetle Mycobiome (BBM) Research Coordination Network. For more information on the BBM international network: Hulcr J, Barnes I, De Beer ZW, Duong TA, Gazis R, Johnson AJ, Jusino MA, Kasson MT, Li Y, Lynch S, Mayers C, Musvuugwa T, Roets F, Seltmann KC, Six D, Vanderpool D, & Villari C. 2020. Bark beetle mycobiome: collaboratively defined research priorities on a widespread insect-fungus symbiosis. Symbiosis 81: 101–113 https://doi.org/10.1007/s13199-020-00686-9.
Running Gels: Electrophoresis Gel Procedure v1
Authors: F Gomez Demian , J. Johnson Andrew , Li You
Published: November 2020

This protocol describes how to run electrophoresis gels at the UF Forest Entomology Lab. This protocol is part of the Bark Beetle Mycobiome (BBM) Research Coordination Network. For more information on the BBM international network: Hulcr J, Barnes I, De Beer ZW, Duong TA, Gazis R, Johnson AJ, Jusino MA, Kasson MT, Li Y, Lynch S, Mayers C, Musvuugwa T, Roets F, Seltmann KC, Six D, Vanderpool D, & Villari C. 2020. Bark beetle mycobiome: collaboratively defined research priorities on a widespread insect-fungus symbiosis. Symbiosis 81: 101–113 https://doi.org/10.1007/s13199-020-00686-9.
Ultra-High Macro Photography of Bark Beetles v1
Authors: F Gomez Demian , J. Johnson Andrew
Published: November 2020

This protocol explains the process of taking high quality photos of bark and ambrosia beetles, creating the image stacks, and processing the images in image editing software (Gimp or Photoshop). This protocol is part of the Bark Beetle Mycobiome (BBM) Research Coordination Network. For more information on the BBM international network: Hulcr J, Barnes I, De Beer ZW, Duong TA, Gazis R, Johnson AJ, Jusino MA, Kasson MT, Li Y, Lynch S, Mayers C, Musvuugwa T, Roets F, Seltmann KC, Six D, Vanderpool D, & Villari C. 2020. Bark beetle mycobiome: collaboratively defined research priorities on a widespread insect-fungus symbiosis. Symbiosis 81: 101–113 https://doi.org/10.1007/s13199-020-00686-9.
Corona Detective User Protocol V2.0 v2
Authors: Aronoff Rachel , Aidelberg Guy
Published: November 2020

Corona Detective is based upon a molecular amplification strategy inspired by the ‘GMO Detective’ method, in order to detect the virus causing Covid-19. Done not only without complicated equipment, but with a simple +/- fluorescent readout, the Corona Detective is very specific. Furthermore, controls to ensure sensitive detection, without false positives or negatives, are intrinsic to this solution. The final product, strips/plates of tubes with dry reagents, specific for Corona and a control gene (extraction control), can be shipped anywhere, without cold-chain dependence. Critically, monitoring tests could be run by ordinary people, by following this protocol. (Even kids have successfully participated in GMO detective workshops, also soldering their own fluor detectors.) This user guide will allow you to test samples with this system, provided as freeze-dried reaction components in 0.2ml tubes made by this protocol (other formats possible e.g. 8-tube strips, 96-well plates, 1000 reactions, etc.). Human or clinical samples should only be run in settings with access to appropriate biosafety facilities, of course. Acknowledging the JOGL Open Covid 19 Initiative and all the #proj nucleic-acid-amplification team for support.
Research Care and Teaching Care Research in the Faculty of Nursing at Universidad de Antioquia. Testimonies and Legacies in 70 years of Institutional Life, 1950-2020
Authors: Posada Vera Elvigia María , Arias López Beatriz Elena
Published: November 2020

The development of care research and its teaching in the Faculty of Nursing at Universidad de Antioquia cannot be understood outside the context in which it emerges and from the trajectory of its leading players. This is how this article will present a synthesis of the future of research, with its principal milestones and events in institutional history, in dialogue with the trajectories of four teaching nurses, protagonists of key moments in said history and living testimony of 70 years of institutional life. This panorama seeks to constitute a referent for strategic reflection, which inspires new generations to meet the research challenges and teach care research.
Quality of life assessment in chronic wound patients using the Wound-QoL and FLQA-Wk instruments
Authors: Vogt Tatiele Naiara , Koller Francisco José , Dias Santos Pamella Naiana , Lenhani Bruna Eloise , Guimarães Paulo Ricardo Bittencourt , Kalinke Luciana Puchalski
Published: November 2020

Objective. To evaluate changes in the quality of life of patients with chronic wounds.

Methods. Quantitative research with a cross-sectional design performed with 100 patients with chronic wounds from a university hospital and a Basic Health Unit in southern Brazil. The mean values of the domains of the instruments Wound Quality of Life (Wound-QoL) and Freiburg Life Quality Assessment Wound were compared with sociodemographic variables of age, sex and education.

Results. The average age of the participants was 60.98 years old; 41% had diabetic ulcers and 83% treated the wounds for more than 24 months. The total quality of life value was below the mean with 37.50/100 with (Wound-QoL) and 44.20/100 with (FLQA-Wk). The variables of gender, and educational level were not correlated with either of the two instruments used to assess the quality of life. The age variable was significantly correlated with the satisfaction item of the FLQA-Wk.

Conclusion. The quality of life of patients with chronic wounds was considered poor. The age variable was correlated with the satisfaction domain, showing that the older the age, the lower the satisfaction. The use of instruments to evaluate the quality of life of patients with chronic wounds may help an effective treatment plan.
Funcionalidad y convivencia del español y el vasco en el paisaje lingüístico de Bilbao
Authors: Fernández Juncal Carmen
Published: November 2020

El español y el vasco conviven desde siglos atrás con diferentes grados de permeabilidad y complementariedad, dependiendo del entorno físico y temporal en el que se desarrolla esa coexistencia. El presente estudio, de carácter mixto, cuantitativo y cualitativo, examina el actual paisaje lingüístico de Bilbao, para determinar las diferentes funciones que asumen las dos lenguas en un territorio donde un uso mayoritario del español alterna con una política muy activa de promoción del vasco. A partir de un corpus de imágenes con textos públicos, se llevó a cabo un proceso de clasificación de los signos lingüísticos de acuerdo con diversos parámetros. El análisis cuantitativo resalta la presencia minoritaria del vasco respecto del español, como reflejo del empleo de esas dos variedades en esa misma área. También se deduce un reparto de funciones entre ambas: mayor función informativa-denotativa para el español y mayor función simbólicaconnotativa para el vasco. Esta situación hace reconsiderar los papeles tradicionales entre lenguas mayoritarias y lenguas minoritarias.
Dealing with the Past: Definitions and Descriptions of the History of Translation
Authors: Ordóñez-López Pilar
Published: November 2020

This study examines how the history of translation has been presented to a wide readership in reference works such as translation studies encyclopedias and handbooks, providing valuable insights into the evolution of the perspectives from which the definition and description of this area has been approached over time. Our study of reference works published over a period of fifteen years shows that attempts have been made to construct an epistemic and methodological framework (a prerequisite for systematic historical enquiry), to define the object(s) of study, and to provide a comprehensive account of the concept of translation throughout history. However, the multifaceted nature of the history of translation makes it difficult to provide clear-cut definitions and descriptions, which makes this a rather diffuse area of knowledge. Furthermore, despite recurrent calls for a more inclusive approach, the account of the past of translation continues to be predominantly canonical and Westernized.
¿Quién tiene derecho a opinar sobre política lingüística en Perú? Un análisis crítico del discurso
Authors: Lovón-Cueva Marco Antonio , Quispe-Lacma Alexandra Paola
Published: November 2020

En el 2007, el proyecto de la “Ley que regula el uso, preservación, desarrollo, recuperación, fomento y difusión de las lenguas originarias del Perú” generó una serie de debates y confrontaciones verbales dentro y fuera del parlamento. Entre ellos destacó el encuentro verbal de las excongresistas Martha Hildebrandt, opositora al proyecto, y María Sumire, defensora de la aprobación. Hildebrandt, lingüista de profesión, y Sumire, abogada de profesión y reconocida como indigenista, formularon discursos de autodefensa y de exclusión. El objetivo de este artículo es analizar los discursos de estas congresistas, los cuales determinaron la decisión política sobre quién tenía el derecho de opinar sobre política lingüística en Perú. Los discursos son estudiados desde el análisis crítico del discurso, con un enfoque en las estrategias léxicas y discursivas empleadas por las congresistas en sus declaraciones, pues estas revelan sus formas de pensar. Los resultados sugieren que, en ambos casos, aunque en uno más que en otro, se reproducen relaciones jerárquicas de poder y prácticas sociales discriminatorias.
A Methodical Approach to Accelerated Screening of Card Assemblies, Static Burn-In Case
Authors: Pugacz-Muraszkiewicz Igor
Published: November 2020

The methodical approach presented for screening cards establishes values of critical parameters, such as apparent activation energy and maximum temperature hence shortest time for screening, and statistical life distributions of assemblies. We conducted one step-stress and two life tests at 120°C (248°F) and 135°C (275°F) using relatively small samples of 40 and 50 cards per test, which, nonetheless, gave us the desired information. The approximate screening parameters that resulted have been successfully used to tailor the stress screening of card assemblies. In our experiments, a trimodal, log-normal life distribution has been revealed, which seems to suggest that the traditional bathtub curve of a life distribution is not applicable to card assemblies.
Improved Materials Characterization for Spacecraft Applications
Authors: Cull Ray
Published: November 2020

The Air Force Materials Laboratory currently has two programs to improve the characterization of spacecraft-type materials for their contamination potential. The first program, Material Selection Criteria, is to develop a standardized out-gassing and condensation test providing kinetic data to support contamination models. The test will include quartz crystal microbalances, an effusion cell, and a mass spectrometer. The second program is to develop a chamber at Arnold Engineering and Development Center to determine the effects of contamination on sensitive spacecraft surfaces. The chamber should be capable of measuring change in solar absorbence on thermal control surfaces, change in transmittance of a Germanium window and change in efficiency of a solar cell, all as a function of contaminant mass level of the surface.
Packaging Films for Electronic and Space-Related Hardware
Authors: Shon Estrelita , Hamberg Otto
Published: November 2020

Flexible packaging films are used to bag and/or wrap precision cleaned electronic or space hardware to protect them from environmental degradation during shipping and storage. Selection of packaging films depends on a knowledge of product requirements and packaging film characteristics. The literature presently available on protective packaging films has been updated to include new materials and to amplify space-related applications. Presently available packaging film materials are compared for their various characteristics: electrostatic discharge (ESD) control, flame retardancy, water vapor transmission rate, particulate shedding, molecular contamination, and transparency. The tradeoff between product requirements and the characteristics of the packaging films available are discussed. Selection considerations are given for the application of specific materials of space hardware-related applications. Applications for intimate, environmental, and electrostatic protective packaging are discussed.
Clean Room Considerations for Avoiding Molecular Contamination
Authors: McClellan Martin
Published: November 2020

Control of contamination for optical products, especially those operating in the ultraviolet spectrum, is examined from three perspectives: materials involved, personnel controls, and environmental conditions. These control functions assume even greater significance when large clean room facilities are required for complex aerospace assemblies, and many clean room products or industry standard practices are not necessarily applicable. Every material introduced into a clean room environment is a potential contaminant, and must be reviewed as part of the operational screening process. Plastics commonly used in the design of clean room products can sometimes outgas and thus degrade optical performance. Facilities rework modifications, local or remote, can introduce contaminants into the air handling system which could produce deleterious effects on critical hardware. Lessons learned and the solutions that have been developed at Perkin-Elmer are discussed in several key areas: modular clean room procurement, verification of HEPA filters, clean room maintenance, design and operational certification and materials controls.
Filter Media Design for High Purity Air Applications
Authors: Schaefer James , Barris Marty , Liu Benjamin
Published: November 2020

The design of high performance filter media for HEPA and ULPA applications is examined comparing theoretical predictions with experimental data. The analysis employs a hybrid filtration model. Pressure drop and particle collection efficiency in the region of minimum efficiency where particle diffusion is decreasing and particle interception is increasing as the particle size increases are examined as functions of particle diameter, velocity, and media geometry including fiber diameter, solidity, and thickness.

Several grades of filter media are characterized and tested for particle sizes in the region of the point of minimum efficiency at typical media rating and application velocities. Filter media performance comparisons are made that show how the point of minimum efficiency can be altered by velocity and media geometry changes. This information is used for a discussion of HEPA and ULPA media performance rating criteria with respect to test and application conditions.

Based upon the results of this study, filter media design, analysis, evaluation and application tools are presented for optimizing high performance filter media for HEPA applications, with suggested future trends based upon projected needs for improving the performance of HEPA media.
Calculating the Obscuration Ratio Due to Particle Surface Contamination
Authors: Barengoltz Jack
Published: November 2020

The obscuration ratio of a surface contaminated by particles is a useful characterization of the degree of cleanliness of the surface. The many effects proportional to the square of particle size are also proportional to the obscuration ratio. However, the calculation of the fraction of the total surface area covered by particles for the typical distributions encountered cannot be performed by elementary methods. A useful method for the calculation of the obscuration ratio for particle distributions assumed to follow a generalized MIL-STD-1246A form is presented. In addition, the validity of an estimation method for measured, discrete distributions is established by the derivation of upper and lower bounds on the desired quantity.
Managing Project Technical, Cost and Schedule Risks
Authors: Feiler Alfred , Geminder Robert
Published: November 2020

An innovative technique for managing project risks in the aerospace and defense industry, that has been used on over 100 projects, is developed in this paper.

The technique is, in effect, a "second generation PERT" that accounts for, and deals with, the many uncertainties that impact project schedule, resource and cost performance. Included are factors such as: specification uncertainties; design, material and process uncertainties; escalation of cost factors; availability of qualified contractors and specialized equipment; contractor productivity; timeliness of material, equipment, and information deliveries; transportation and logistics support; environmental factors; rejects, rework and other delays due to quality of materials and products; and, mechanical breakdown and malfunctions during system/component testing and commissioning.
Shear StressTM Cleaning for Surface Departiculation
Authors: Musselman Robert , Yarbrough Tom
Published: November 2020

A cleaning technique widely used by the nuclear utility industry for removal of radioactive surface contamination has proven effective at removing non-hazardous contaminant particles as small as 0.1 micrometer (μm). The process employs a controlled high-velocity liquid spray inside a vapor containment enclosure to remove particles from a surface. The viscous drag force generated by the cleaning fluid applies a shear stress greater than the adhesion force that holds small particles to a substrate. Fluid mechanics and field tests indicate general cleaning parameters.
Deterministic Failure Prediction
Authors: Burkhard Alan
Published: November 2020

This paper presents an approach to equipment reliability prediction based on the concept that failures of electronic equipment are ultimately due to chemical, mechanical and/or metallurgical processes. These processes follow physical laws which can be modeled and the amount of life available for exposure to a given stress condition can be calculated. Using this approach, a failure-free operational period can be calculated during which, for all practical purposes, the probability of failure is essentially zero. Such an approach is used to design structural systems such as airframes, bridges, etc. But to implement such an approach will require a change in mindset and philosophy in terms of how avionics reliability and failures are considered. This paper presents concepts and ideas of how this can be and is beginning to be implemented.
Evaluation of the Infrared Test Method for the Olympus Thermal Balance Tests
Authors: Donato Marc , Green Jerry , St-Pierre Dany , Reeves Murray
Published: November 2020

The present work reports on the performance of the infrared test techniques developed and used for the thermal balance testing of the Olympus spacecraft thermal model. Developments in the area of computer software, radiometers, and temperature measurement systems are presented. The power control and data acquisition systems are also detailed. A summary of the test results shows that temperature differences between test and predictions are in agreement within the values obtained in past programs for an uncorrelated mathematical model.
A Quantitative Method of Tailoring Input Spectra for Random Vibration Screens
Authors: Curtis Allen , McKain Richard
Published: November 2020

This paper presents a rational method by which an effective random vibration screen may be developed efficiently and quantitatively. In summary, a Flaw Precipitation Threshold (FPT) was derived from measurements of vibration response at known flaw locations. Responses were measured on a variety of modern electronic and electro-mechanical equipment, manufactured by five different manufacturers, during ongoing vibration screens. A vibration screen can be tailored for a piece of equipment by performing a global vibration response survey and adjusting the input spectra so that the response falls within the FPT.
A Polarization Diversity Two-Color Surface Analysis System
Authors: Knollenberg Robert
Published: November 2020

A surface analysis system is described that uses an unconventional illumination approach. The system uses two orthogonally polarized lasers that may have different frequencies (colors). The lasers used are both He-Ne devices, with either both operating at 633 nm (red), or one at 633 nm and one at 543 nm (green). The system is capable of sizing polystyrene latex (PSL) particles on bare silicon wafers as small as 0.1 μm and provides first-order differentiation between particles and defects. The scanning function is most similar to that used in optical disk drives. The optical system is modeled after a dark-field microscope and thus is capable of analyzing particles on transparent materials, as well as highly reflective materials such as silicon and dielectric mirrors. The instrument can also be configured to analyze polished memory disks, optical elements, and ring laser gyro mirrors.
Thermal Environment Simulator for Vacuum Testing of Large Spacecraft
Authors: Marshall T.
Published: November 2020

A thermal environment simulator (TES) with 56 independently controllable temperature zones has been developed for Martin Marietta's Space Simulation Laboratory. This simulator is designed to test shuttle payloads in a thermal vacuum chamber with liquid nitrogen cold walls. The thermal environment simulator is an alternative to a 4.9-m (16-tt) diameter vertical beam solar simulator and two-axis gimbal system. The simulator can accommodate larger test articles at a lower cost. It provides complex heat flux distributions by surrounding the test articles with a multifaceted temperature environment. Issues resolved during initial operation included vacuum and cryogenic compatibility, control capabilities, instrumentation, calibration, heat flux uniformity, and reliability.
Model Study for Optimization of Cleanroom Airflows
Authors: Yamamoto Toshiaki , Donovan Robert , Ensor David
Published: November 2020

A menu-driven numerical simulation was developed to model the airflow in a typical industrial process cleanroom. The effects of changing entry velocity, isolating curtain height, and return airflow are evaluated. Theoretical guidelines for minimizing the strength of recirculation zones and optimizing the airflows in the cleanroom are discussed. These simulations help identify cleanroom designs that minimize the transport of particle contamination.
Space Shuttle Solid Rocket Motor Testing for Return to Flight: Transient Pressure Test Article Test Program
Authors: Vibbart Charles
Published: November 2020

The Transient Pressure Test Article (TPTA) test program is being conducted at a new test facility located in the east test area at the National Aeronautics and Space Administration's (NASA's) Marshall Space Flight Center (MSFC) in Huntsville, Alabama. This facility, along with the special test equipment (STE) required for facility support, was constructed specifically to test and verify the sealing capability of the redesigned solid rocket motor's (RSRM) field, igniter, and nozzle joints.

The test article consists of full scale RSRM hardware loaded with inert propellant and assembled in a short stack configuration. The TPTA is pressurized by igniting a propellant cartridge capable of inducing a pressure rise rate that simulates the ignition transient that occurs during launch. Dynamic loads are applied during the pressure cycle to simulate external tank attach (ETA) strut loads present on the ETA ring. Sealing ability of the redesigned joints is evaluated under joint movement conditions produced by these combined loads since joint sealing ability depends on seal resilience velocity being greater than gap opening velocity. Also, maximum flight dynamic loads are applied to the test article which is either pressurized to 600 psia using gaseous nitrogen (GN2) or applied to the test article as the pressure decays inside the test article on the down cycle after the ignition transient cycle.

This paper will present the uniqueness of this new test facility with respect to its capabilities. It will also touch on both the topic of test effectiveness versus space vehicle flight performance and new aerospace test techniques, as well as presenting a comparison between the old SRM design and the RSRM.
Particle Capture Mechanisms in Gases and Liquids: An Analysis of Operative Mechanisms in Membrane/Fibrous Filters
Authors: Grant Donald , Liu Benjamin , Fisher Wayne , Bowling R.
Published: November 2020

Membrane filters are capable of reducing particles in fluids to very low levels through the action of several capture mechanisms. However, the effectiveness of these mechanisms at removing particles is influenced by the properties of the fluid undergoing filtration. This article reviews the theories of particle capture mechanisms and discusses their relative effectiveness in various fluid types.

Theory indicates that membrane filters remove essentially all particles from gas streams by interception and diffusion. In liquids, the operative particle capture mechanisms depend upon the physical chemistry of the particle-fluid-filter media system. Under favorable chemical conditions, the operative capture mechanisms are the same as in gases with essentially all particles removed. However, under unfavorable chemical conditions, only particle sieving occurs, and capture is greatly reduced. In addition, captured particles are less tightly held in liquids and shearing forces are larger, hence particle reentrainment is more likely.
Correlation Studies on Surface Particle Detection Methods
Authors: Peterson Ronald , White II James
Published: November 2020

The accurate determination of dust levels on optical surfaces is necessary to assess sensor system performance. A comparison study was made on several particle measurement methods including those based on direct imaging and light scattering. The effectiveness of removing the particles from the surface prior to determining particle size distributions was also assessed.

These studies revealed that some methods, especially those requiring particle removal before analysis, are subject to large systematic errors affecting particle size distributions. Thus, an understanding of the particle measurement methods employed is necessary before any surface cleanliness or obstruction value assignments are accepted as a true representation of an optical surface contamination condition.
Sub 0.1 Micron Particle Detection and Analysis Using High Sensitivity Nephelometry
Authors: Kreikebaum Gerhard
Published: November 2020

This article describes the principles of operation of a novel approach to liquid nephelometry. The use of a modulated laser diode light source in combination with the liquid cell design allows measurements with a sensitivity of 0.00001 NTU, one to two orders of magnitude more sensitive than previous designs.

Data presented indicate the instrument response to sub 0.1 micron PSL spheres as well as sensitivity to colloidal silica to 6.3 parts per billion (ppb).

Illustrative examples will be given for the application of two simultaneous liquid nephelometers for filter collection efficiency testing as a function of challenge particle size, filter loading, and flow rate.
Measurement of Particle Concentrations in Central Chemical Delivery Systems
Authors: Grant Donald
Published: November 2020

This article evaluates recently developed high sensitivity optical particle counters for measuring particle concentrations in high purity semiconductor process chemicals. The results indicate that use of these low sampling rate counters is appropriate for obtaining accurate measurements. The results also indicate that particles in these chemicals may come from two sources: small particles that pass through the filters used to purify the chemicals and larger particles that originate at or downstream of the filter.
Lessons Learned in Vibro-Thermal Acoustic Tests
Authors: Vasiliou Petros
Published: November 2020

An environmental test technique developed to test air-to-air missiles at the Pacific Missile Test Center at Point Mugu, California, has been implemented for the past 15 years. This technique recreates a captive flight environment in which the missile is simultaneously subjected to thermal, vibration, and functional testing. This article describes this technique, Flight Test Simulation, the facilities utilized, and lessons learned as they have been applied in recent tests.
Supply Plenum and Airflow Uniformity in Cleanrooms
Authors: Sadjadi Reza , Liu Benjamin
Published: November 2020

The uniformity of airflow distribution in a cleanroom has been studied as a function of supply plenum geometry. The flow uniformity is measured experimentally by means of a hot-wire anemometer mounted at the end of a mechanical arm attached to an X-Y table. In addition, a numerical simulation procedure has been developed to calculate the flow velocity below the ceiling filter by taking into account the influence of supply plenum geometry. In the specific system studied, the major cause of flow non-uniformity is the turning of the flow at the end of the supply plenum and the impingement of flow directly at the filter face. The numerical result shows that the flow non-uniformity can be decreased by increasing the size of the supply plenum or reducing the velocity of the airflow in the plenum.
The Evaluation of Alternatives to Ozone-Depleting Chlorofluorocarbons
Authors: Sellers Robin
Published: November 2020

As part of an international effort to reduce the depletion of stratospheric ozone, a test program has been developed and implemented to evaluate materials or processes as alternatives to chlorofluorocarbons (CFCs). This article discusses this development and the results of these industry-government efforts, which have expedited the transition to acceptable cleaning alternatives.
Computer-Aided Reliability Finite Element Methods
Authors: Followell David , Liguore Salvatore , Perez Rigo , Yates W. , Bocchi William
Published: November 2020

Finite element analyses (FEA) have emerged as a process for assessing stresses and strains in electronic equipment in order to compute the expected structural life. However, potential pitfalls may compromise accuracy. Guidelines have been established to improve the accuracy of these results. A method has been outlined that allows simplified linear FEAs to be used instead of the more complex elastic-plastic nonlinear FEA. Guidelines for mesh generation have been established to eliminate arithmetic errors caused when materials with large stiffness differences are adjacent to each other. The accuracy of FEAs when dealing with very small dimensions has been verified. Procedures for combining various loadings in order to predict life have been established for materials that exhibit stress relaxation and for those that do not. With these guidelines, FEAs can be an effective tool to predict the structural life of electronic equipment.
Assessing Wiping Materials for Their Potential to Contribute Particles to Clean Environments: Constructing the Stress-Strain Curves
Authors: Mattina Charles , Paley Steven
Published: November 2020

An experimental procedure for stressing wipers such that the magnitude of the stresses are known, reproducible, and applied over a reasonable range, and such that the number of particles generated thereby is easily determined, is described. The stresses are administered by dragging weights of known mass and cross-sectional area across the surface of wetted wipers at known velocities and simultaneously measuring the resultant frictional forces. From these physical measurements, the frictional energy absorbed by the wipers is calculated. Plotting the number of particles generated versus this energy results in an empirical construction of the stress-strain curves.

Data and stress-strain curves are presented for a variety of wiping materials. The shapes of the curves are interpreted in terms of the physical characteristics of the wipers. The fact that the curves are independent of the rate with which energy is administered (i.e., the power) is discussed.

In an earlier presentation (1989 Annual Meeting of the Fine Particle Society, Boston, Massachusetts), a method for estimating the potential of wiping materials to contribute particles to clean environments was described. The research was predicated on the hypothesis that a wiper both releases particles already present on its surface and generates particles that do not yet exist but, in response to an applied mechanical stress, are created in some proportion to that stress. Also hypothesized was the existence of stress-strain curves for wiping materials, such that the number of particles released and generated per unit area of wiper is a function of the applied stress per unit area of wiper. The y-intercepts of these stress-strain curves, then, are interpretable as the number of particles released from a wiper under conditions of zero (or near-zero) mechanical stress. The authors gave a detailed description of a methodology for determining these y-intercepts and speculated on possible techniques for empirically determining the shape of the stress-strain curves.
A Three-Dimensional UltrasonicAnemometer to Measure the Performance of Clean Zone Air Delivery Systems
Authors: Hope David , Milholl Dan
Published: November 2020

The three-dimensional ultrasonic anemometer (3DUA) is an instrument that can measure airflow velocities in three axes simultaneously. From the data gathered, airflow direction and air tubulence intensity may be determined. Using a propietary software package, results are available immediately on-line, in either a tabular or graphic format. This instrument was initially chosen to evaluate the performance of a new cleanroom ceiling system that had integrated the lighting and sprinklers within the filter support grid. Additional work was later performed to evaluate the impact of a membrane ceiling on a turbulent air supply.
Multichannel Simultaneous Digital Tracking Filters for Swept-Sine Vibration Control
Authors: Pelletier Marcus , Underwood Marcos
Published: November 2020

The digital control of swept sine-wave tests and the associated theory needed for swept sine-wave synthesis and analysis will be discussed. This type of testing requires that the digital vibration control system drive the actuator subsystem with an analog signal. This signal is a low-distortion sine wave with a smoothly varying frequency and amplitude. The testing also requires that the controller be able to measure the response of this type of excitation by way of a control transducer mounted at some chosen point on the device under test. This paper will concentrate on the details of output signal generation to enhance its accuracy and suitability for complex heterodyne generation. The complex heterodyne is used in conjunction with 0-Hz intermediate frequency detectors to implement a digital tracking filter. Digital low-pass filters are used to implement 0-Hz intermediate frequency detectors. The tracking filter is used for time-variable spectral analysis6 (i.e., determining the instantaneous complex amplitude of a sweeping sine wave as encounted in swept sine testing).
Evaluation of a Nonvolatile Residue Monitor for Measurement of Residue after Evaporation of IPA and Acetone
Authors: Kinney P. , Pui D. , Liu B. , Kerrick T. , Blackford D.
Published: November 2020

The nonvolatile residue monitor (NRM) operated in the batch mode has been investigated for measuring residue after evaporation (RAE) of isopropyl alcohol (IPA) and acetone. IPA, acetone, and water were doped with known concentrations of known contaminants and then measured with the NRM to determine its calibration for these liquids. The calibrations were measured with different types of contaminants and with different drying temperatures. The NRM's calibration was identical for IPA, acetone, and water when calibrations were performed with water-soluble contaminants. Less ideal behavior was observed with water-insoluble contaminants. The NRM's performance in evaluating high purity semiconductor grade isopropyl alcohol and acetone was also investigated. RAE levels were measured in solvents purchased from four different suppliers to the semiconductor industry. The NRM was able to differentiate between the suppliers.
Partial Pressure Analysis in Space Testing
Authors: Tilford Charles
Published: November 2020

For vacuum-system or test-article analysis, it is often desirable to know the species and partial pressures of the vacuum gases. Residual gas or partial pressure analyzers (PPAs) are commonly used for this purpose. These are mass spectrometer-type instruments, most commonly employing quadrupole filters. These instruments can be extremely useful, but they should be used with care. Depending on the instrument design, calibration procedures, and conditions of use, measurements made with these instruments can be accurate to within a few percent, or in error by two or more orders of magnitude. Significant sources of error can include relative gas sensitivities that differ from handbook values by an order of magnitude, changes in sensitivity with pressure by as much as two orders of magnitude, changes in sensitivity with time after exposure to chemically active gases, and the dependence of the sensitivity for one gas on the pressures of other gases. However, for most instruments, these errors can be greatly reduced with proper operating procedures and conditions of use. In this paper, data are presented illustrating performance characteristics for different instruments and gases. Operating parameters are recommended to minimize some errors. Calibrations procedures are described that can detect and correct other errors.
Swept Sine Vibration Test Conservatism
Authors: Hine M.
Published: November 2020

The excessive overtest associated with the swept sine vibration test method was measured quantitatively using the index of conservatism and the associated overtest factor for a dynamic mass model of a typical spacecraft component. The response to a fixed amplitude sine sweep test was compared with the flight transient vibration environment for sweep rates of 2, 4, and 6 octaves/min and 300 Hz/min. A response-limited test was also conducted at 6 octaves/min. The conservatism was measured using several characterizations; namely: number of peaks exceeding, ranked peaks, shock response spectrum, shock intensity, three-dimensional shock response spectrum, and ranked peaks. Overtest factors exceeding an order of magnitude were measured for the test response with the number of peaks exceeding and the three-dimensional shock response spectrum.
Statistical Monitoring Techniques for Contamination Data
Authors: Montgomery Douglas , Keats J. , Fowler John , Runger George , Rajavelu Geetha
Published: November 2020

Monitoring of particle contamination by statistically based methods is used extensively in semiconductor manufacturing. Often Shewhart-type control charts are used for this purpose. These charts suffer from some potential disadvantages in this application environment. Specifically, they are slow to detect shifts or changes in the level of particle contamination and, in some situations, the underlying statistical assumptions of the charts are inappropriate for contamination data. We suggest the use of cumulative sum and exponentially weighted moving average control charts for monitoring particle contamination. The advantages of these charts for the types of particle contamination data typically encountered in semiconductor manufacturing are discussed and illustrated with examples.
Shaker Simulation of Random Vibration with a High Kurtosis Value
Authors: Steinwolf A.
Published: November 2020

This paper presents a vibration test technique for extending the tails of amplitude probability distribution beyond the Gaussian values as is characteristic for vibration of ground vehicles on a rough road or terrain. The method proposed uses the commonly accepted approach of applying pseudorandom excitation in the form of a Fourier expansion. The procedure described in this paper can be implemented by updating currently available digital vibration controllers. The solution for amplitude domain fitting is based on an analytical expression derived for the kurtosis parameter of the polyharmonic process in terms of amplitudes and phase angles for any number of harmonic components. The results of theoretical analysis are embodied in software subjected to verification in computer and experimental tests. Even with additional kurtosis control, the closeness of the generated and desired spectra is the same as for the Gaussian simulation of power spectral density. Hence, this new technique for amplitude domain matching is not accompanied by the deterioration of ordinary test capabilities in the frequency domain.
Clomiphene stair-step protocol for ovulation induction in women with polycystic ovarian syndrome
Authors: Al Ghazali Basima
Published: November 2020

The objective of this study is to evaluate the efficacy of the clomiphene stair-step protocol to induce ovulation in women with polycystic ovarian syndrome (PCOS) compared to traditional protocol. This single center randomized controlled trial was undertaken. A 140-patients who met all of the inclusion criteria were divided into two main groups and induction of ovulation for both protocols was performed. Follow up of follicular maturation is done by transvaginal ultrasound. The time to ovulation with the stair step protocol was 21-28 days as compared with the traditional protocol which was 42-70 days. The dose dependent ovulation rate was 43% at 100 mg with the stair step protocol compared with 25.3% with the traditional regimen and the ovulation rate at 150 mg was 21.6% with the stair step protocol compared with 14.7% with the traditional protocol while the clomiphene citrate resistance rate was higher with the traditional protocol 38.7% as compared to the stair step method which was 20% which are statistically significant. This randomized controlled trial suggests that clomiphene stair step protocol decreases the time to ovulation and may improve ovulation rates in clomiphene-resistant women.
Expression of orphan receptor GPR15/BOB up-regulated in systemic lupus erythematous/crosstalk with pro-inflammatory cytokines
Authors: Granter Johannes , B. Calvin Michael
Published: November 2020

Systemic lupus erythematosus (SLE) is a chronic inflammatory disease that has protean manifestations and follows a relapsing and remitting course. More than 90% of cases of SLE occur in women, frequently starting at childbearing age. The pattern of tissue injury in SLE is primarily related to the formation of the immune complexes deposits that can induce the inflammatory response by activation of adhesion molecules on endothelium, resulting in the recruitment of pro inflammatory leukocytes. The goal of this study was to investigate the expression of orphan receptor GPR15/BOB in the lesion/ peripheral blood of SLE patients and non-SLE patients. Messenger RNA expression was examined by reverse-transcription polymerase chain reaction (RT-PCR) and GPR15/BOB protein by immunofluorescence. Cytokines were analyzed from blood serum using enzyme linked immunoassay (ELISA) for IL-6 and INF-α. Further; GPR15/BOB expression on peripheral blood leukocytes was analysed by flow cytometry. GPR15/BOB (P=0.002) expression levels were significantly increased in lupus patients compared to age-matched controls. African American women with lupus had a 2-fold increase in GPR15/BOB expression level when compared to their healthy controls or European American lupus patients. Serum levels revealed significant increases in expression of IL-6, IFN-γ and TNF-α in lupus patients with expression of GPR15/BOB compared to non-expression of GPR15/BOB -lupus patients. This study shows expression of GPR15/BOB is up-regulation in SLE patients and provides an opportunity for targeting with antagonist as a novel therapy for SLE.