bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemical Integration and Contamination Control In Hard Disk Drive Manufacturing
Authors: Nebenzahl L. , Nagarajan R. , Wong J. , Volpe L. , Whitney G.
Published: April 2015

As we approach the turn of the century, the demand for storage is rapidly increasing, fueled by multimedia and its associated applications. Hard disk drive (HDD) manufacturers continue to respond by chasing the areal density curve to provide higher capacity and higher performance disk drives. The required technology changes are expected to aggravate performance and reliability problems, such as stiction, associated with organic contamination; thermal asperities, associated with particulate contamination; and corrosion, associated with ionic contamination. Anticipation and proactive resolution of chemical integration and contamination control problems are key to the successful development and manufacturing of advanced HDDs. In this paper, types and sources of contamination that can impact HDD performance are described; various contamination-related problems are reviewed; and a methodology by which successful chemical integration in the hard disk drive business can be accomplished is outlined.
Orbital Experience from an Integration and Test Perspective
Authors: Tosney William , Quintero Andrew
Published: April 2015

Space vehicle schedule and cost reduction strategies tend to focus on test optimization without a comprehensive analytical approach to the impact on mission success. This study provides valuable stochastic insights into orbital physics of failure while identifying potential relationships to ground integration and test processes by analyzing data across a large population of space vehicle programs. Failure data analysis uses reliability growth modeling techniques to provide greater insight into environmental test effectiveness. Results show correlations between orbital failures, environmental test, hardware retest, and hardware categories. Test strategies are discussed to mitigate risk of orbital failures for hardware subjected to varying degrees of retest and late integration.
Comprehensive Particle and Fiber Testing for Cleanroom Wipers
Authors: Battacharjee Himansu , Paley Steven
Published: April 2015

A microscopy-based measurement technique has been developed for accurately quantifying the total number of particles and fibers in all size ranges released from a cleanroom wiper during conditions of simulated use. The method uses both optical and scanning electron microscopy in conjunction with computerized image analysis for counting particles and fibers. The technique uses a single sample preparation for the extraction of both particles and fibers from the wiper. Seven cleanroom wiping products were examined using this measurement technique. The results are shown for the various size groupings of particles and fibers. A composite measure of contamination is presented. This work reveals that a cleanroon wiper may appear very clean in certain size categories and appear extremely dirty in others. The results of this study show that all size ranges of particles and fibers need to be examined when determining the total contamination risk posed by any cleanroom wiper.
Exposure of Inert Gas Purifiers to Air: Studies on Hydrocarbon Release in Resin-Based vs. Nickel-Based Purifiers
Authors: Alvarez Dan , Cook Joshua , Lee Jin , Tram Allan , Spiegelman Jeffrey
Published: April 2015

Gas purification is an integral part of many semiconductor manufacturing processes. Accidental air contamination into gas delivery systems can lead to adverse consequences. This paper addresses the use of inorganic nickel-based purifiers versus organomentallic resin-based purifiers in the event of air intrusion. Tests were performed under conditions that simulate a large purging error. Both purifier technologies undergo reaction exotherms. Hydrocarbon oil release, which results in catastrophic system contamination, occurs with organometallic resin purifiers. For nickel-based purifiers, system contamination is limited to air breakthrough.
Evaluation of Electrostatic Charges on Aerosol Particle Attractiveness to Silicon Wafers in Class-1 Cleanrooms
Authors: Harrison Michael
Published: April 2015

A series of tests were performed to define the required ion emitter balancing and cleaning frequencies. The voltage drift and discharge time drift were used to determine acceptable maintenance servicing schedules. The ion emitter operating limits were determined experimentally by measuring the maximum electrostatic charge that would build up on a wafer before it was at risk of attracting particles out of the airstream. A site survey was performed on cleanroom equipment and processes using a noncontact field meter to identify critical areas with greater than 1000 V of surface charge. Programs have been initiated which require "at risk" processes to perform specific testing to determine whether ionization emitters are needed.
Characteristics of Wipers and Swabs for Pharmaceutical Applications
Authors: Miscioscio Kathy , Cooper Douglas
Published: April 2015

The manufacture of pharmaceuticals requires clean processing. Wipers are used to remove contaminants, such as chemical films, microbiological entities, and nonbiological particles, by wiping the walls, tables, and equipment and to inhibit biological activity by applying disinfectants. Cleaning protocols can be validated using clean swabs for sampling and sensitive instrumentation for quantification. The characteristics of wipers and swabs suitable for these purposes are explored.
MIL-STD-810F, Test Method Standard for Environmental Engineering Considerations and Laboratory Tests
Authors: Caruso Hank
Published: April 2015

This paper highlights the significant changes introduced with the F-revision of MIL-STD-810, "Test Method Standard for Environmental Engineering Considerations and Laboratory Tests." The major emphasis on test tailoring presented in Part One of the document is described. Significant features of each test method in Part Two are briefly summarized. Detailed discussions of each test method are beyond the scope of this document.
Benchmarking Time and Cost of Semiconductor Fabrication Facilities
Authors: He Min , Chasey Allan , Patel Sachin
Published: April 2015

The semiconductor industry is a high capital investment industry with the cost of a single completely equipped semiconductor manufacturing facility reaching $2.0 billion. A delay in the operation of the facility can cause the manufacturer a loss of millions of dollars worth of opportunity cost and a share of the market. Thus, semiconductor facility owners want their facilities built quicker, at lower cost, and with higher quality standards. However, the exchangeable knowledge of the project cost and project delivery time associated with the construction of semiconductor facilities nationwide is still in the preliminary stage. One major hindrance to the exchangeable knowledge of the project cost and delivery time is the lack of standard definitions to serve as a base for an industry-wide comparison that will allow owners, designers, engineers, and constructors to make decisions at a very early stage of the projects. The purpose of this research is to overcome the segregation of the existing knowledge in semiconductor facilities construction and to generate benchmarks that can gauge the performance level.
How Clean Is It? The Use of Ion Chromatography to Monitor Contamination in Cleanroom Environments
Authors: Newton Beverly
Published: April 2015

Cleanrooms pose a special challenge for cleanliness testing. Contaminants in the form of particles, metals, ions, and organics must be completely removed to ensure defect-free processing. Ions such as chloride, sulfate, nitrate, and ammonia can degrade water surfaces, particularly in the presence of adsorbed water. A number of analytical methods are used to test for cleanliness and contamination control Ion chromatography is used to determine ionic contamination. The presentation will answer the following questions:

• What is ion chromatography?

• How is ion chromatography used to evaluate cleanliness?

• What are the recent improvements that have been made to the technology?

• What are some typical cleanliness testing applications?

• How will the use of ion chromatography help my company?
An Integrated Acoustic Analysis Capability
Authors: Lee Y. , Tolomeo Jason
Published: April 2015

To perform the analysis of multidisciplinary systems in the early design phase, an Integrated Modeling of Optical Systems (IMOS) was developed by NASA/JPL. The existing code has Stationary Statistical Energy Analysis (SEA) capability for acoustic analysis. An implementation of Transient SEA is performed to enhance the IMOS acoustic analysis capability. It is benched marked against industry standard vibroacoustic analysis tools VAPEPS and TRANSTAR. The comparisons are excellent. As an example, it is applied to a generic structure subjected to a realistic transient excitation. The enhanced capability can be applied to the study of microdynamics and other random vibration/shock issues related to the high precision space-borne optical systems.
Effective Collection of Ultrafine Particles with Soft X-Ray Irradiation Under Applied Electric Field and/or Corona Discharge
Authors: Namiki Norikazu , Yoshikawa Fumie , Komatsu Akihiro , Otani Yoshio , Kulkarni Pramod , Biswas Pratim , Kim Yong-Shik
Published: April 2015

Conventional electrostatic precipitators (ESPs) used for exhaust gas treatment equipment and air cleaners have generally been said to have a penetration window in a submicrometer particle size range. Further, recent works have shown that the collection efficiency of particles with a diameter less than about 50 nm decreases due to poor charging by the corona. In this paper, we describe an attempt to use in situ soft X-ray irradiation to enhance the ultrafine particles in the ESP. A laboratory-scale ESP was configured to irradiate particles with soft X-rays. The collection efficiency of the particles was then measured with and without irradiation to examine the enhancement. The results showed a noticeable improvement in the efficiency of ultrafine particles (dp <60 nm) with irradiation. In particular, X-ray irradiation combined with corona discharge was much more effective than irradiation without it. Further, a higher efficiency was obtained with a positive corona than with a negative one.
Online Monitoring of Nanoparticle Contamination in Reactive Gases
Authors: Schmid Otmar , Trueblood Max , Hagen Donald , Whitefield Philip
Published: April 2015

Numerous manufacturing processes require extremely low levels of nanoparticulate contamination to ensure product quality. While modern filters efficiently remove nanoparticles, online monitoring of the cleanliness of possibly reactive process gases is frequently necessary for quality control purposes. For most manufacturing processes, product quality depends on the concentration of particles above a specific threshold size. This paper will describe how to design an online nanoparticle monitoring system (NMS) for reactive (and inert) process gases from commercially available components, and will discuss how to adapt this system to varying process requirements, such as particle threshold size, and type and pressure of process gas. This paper will also describe a method to determine experimentally the performance of an NMS to ensure quality control.
Surface Deposition of Diethyl Phthalate on SiO2 and Si3N4 Wafers in Simulated Cleanroom Environment
Authors: Kang Yuhao , Den Walter , Bai Hsunling , Ko Fu-Hsiang
Published: April 2015

The surface deposition kinetics of airborne diethyl phthalate (DEP), a representative compound for high-boiling-point organic contaminants in cleanroom environments, were investigated in this study. Between the two types of wafer surfaces evaluated, wafer surfaces with oxide (SiO2) and wafer surfaces with nitride (Si3N4), DEP exhibited a stronger propensity to absorb on the SiO2 wafers, presumably due to the greater dipole moment between DEP and SiO2 surfaces. Under well-controlled exposure conditions, the rate parameters of a theoretical surface kinetic model were determined by employing a heuristic algorithm for numerical optimization to match the experimental profile. Subsequently, a series of time-dependent surface DEP concentrations were simulated and validated with the experimental data under various ambient concentrations. Estimation of the allowable wafer exposure durations and the maximum ambient concentrations were exemplified based on the guideline recommended by the International Technology Roadmap for Semiconductors (ITRS).1
Antonomous Environmental Definition of C-130 Flap Well Skin Panel
Authors: Banaszak David , Brown Dansen , Laird David
Published: April 2015

Air Force C-130 aircraft require numerous aluminum doubler repairs on the wing flap skin aft of the right-hand outboard engine. These repairs are costly and require riveting. Rivets often provide new areas of stress concentration, which causes new cracks to develop elsewhere. Boeing and the Air Force Research Laboratory (AFRL) are measuring the thermal and strain environment behind the right-hand outboard engine of a North Carolina Air National Guard (NCANG) operational C-130 aircraft (TN 93-1456) for use in design of a damped repair patch to prevent the growth of cracks in skin under the wing flap panel. During June 2003. AFRL engineers and technicians acquired data using an autonomous damage dosimeter during five operational C-130 flights. The damage dosimeter measures structural strains and temperatures on in-service aircraft to diagnose structural conditions that are difficult to analyze, such as acoustics and high cycle fatigue (HCF). The first flight was from Charlotte, North Carolina to Warner Robins Air Force Base (AFB), Georgia and returned to Charlotte. The last four flights were assault flights where the C-130 simulated cargo drops. Pilots logged the altitude and indicated airspeed, engine speed, and flap positions for the first four flights. Flap position settings were compared with dosimeter temperature and root mean square (rms) strain measurements.

This paper presents typical third octave plots showing engine speed vibratory frequencies, rms time histories (TH), and correlation data for a flight. This paper also presents typical limited data in TH, probability density function (PDF), power spectral density (PSD), and rain flow formats.
A Design for Combining Biological and Semiconductor Cleanrooms for Nanotechnology Research
Authors: Weaver John
Published: April 2015

Nanotechnology brings together various functional areas for interdisciplinary research, making it necessary for them to reside in a single facility. The conjoining of biology, biomedical engineering, and bio-nano-micro-electro-mechanical systems (MEMS) with semiconductor and MEMS processing requires that these technologies coexist in ultraclean facilities, while the facility designs and operating practices are incompatible. This case study describes a design concept in a collaborative research environment that meets biocleanliness goals and International Organization for Standardization (ISO) Class 4 particle concentrations (as defined in ISO 14644-1, Cleanrooms and associated controlled environments—Part 1: Classification of air cleanliness).
Multicomponent Organic Compounds Adsorption/Desorption Model for Prediction of the Lifetime of a Charcoal Filter
Authors: Akiyama T. , Takahashi H. , Gomi H. , Takahashi A. , Takeda H.
Published: April 2015

In an attempt to predict the lifetime of a charcoal filter designed to remove gaseous organic compounds, a model was developed to simulate adsorption and desorption of multicomponent organic compounds in the filter. The model is composed of a mass balance equation and adsorption/desorption rate equations. When a charcoal filter is installed in a cleanroom airconditioning system, numerous types of organic compounds are competitively adsorbed onto adsorption sites (pores) of the activated carbon on the filter, which leads to displacement adsorption phenomenon. In order to consider this phenomenon in lifetime prediction, the adsorption/desorption rate equations are designed to express the concept that organic compounds of different types share or compete with each other for the limited number of adsorption sites. In this model, adsorption/desorption characteristics of each organic compound are represented by multiple parameters. A method was also proposed to estimate parameter values of organic compounds with unknown properties. In this method, the simulation model considers the total organic compound detected by means of gas chromatography (GC) analysis of cleanroom air sampled upstream of the charcoal filter. This newly developed simulation model was validated by comparing simulated and measured adsorption breakthrough curves for a multicomponent system. A charcoal filter with honeycomb-structure media was used in this validation. Simulated values were found to be in agreement with the measured values, which demonstrates that this simulation model is valid.
Experimental Modal Analysis: Efficient Geometry Model Creation Using Optical Techniques
Authors: Pauwels Steven , Debille Jan , Komrower Jeff , Lau Jenny
Published: April 2015

Experimental modal analysis (EMA) is widely used to characterize the dynamic properties of structures. Recently EMA is being used on more complex structures often involving hundreds of measurement points. Modal analysis results are frequently used in combination with numerical models, imposing higher standards on the quality of the modal parameter estimation and the accuracy of the geometry models. These requirements are often contradictory to the availability of test cells and prototypes.

In order to solve this challenge, innovative solutions using optical techniques have been developed that simplify and accelerate the creation of a geometrical model of a test object, while at the same time increase the accuracy of measured coordinates. Industrial applicability of these techniques is proven by a number of benchmarks on real-life structures.
Environmental Chamber Temperature Calibration: Which Method to Use?
Authors: Gibbons David
Published: April 2015

Calibration of environmental simulation temperature test chambers is anything but simple. This article addresses factors that complicate attempts to calibrate these machines, and discusses strengths and weaknesses of various calibration approaches.
Virtual Remaining Life Assessment of Electronic Hardware Subjected to Shock and Random Vibration Life Cycle Loads
Authors: Mathew Sony , Das Diganta , Osterman Michael , Pecht Michael , Ferebee Robin , Clayton Joseph
Published: April 2015

This study presents a physics-of-failure-based virtual remaining life assessment method for assessing the remaining life of an electronic circuit card. The approach is then demonstrated through a case study of a circuit card assembly in the Space Shuttle solid rocket booster. Using thermal and mechanical stress damage models, the accumulated damage in the circuit card due to the life cycle environment loads on the card was calculated. Based on the amount of damage accumulated, the remaining life of the circuit card was estimated.
The Disconnect Between Environmental Testing and Aging, Long-Lived Vehicles
Authors: Caruso Hank
Published: April 2015

Traditional laboratory test strategies and methodologies are structured to identify and correct product defects that occur relatively early in the life of a product. Issues associated with aging, long-lived vehicles, such as aircraft, involve degradation mechanisms that may not be thoroughly investigated in the test laboratory with current test approaches. Long-lived vehicles (platforms) do not experience end of life in the same way that an electronic sub-element might. Rather than being retired, an aging platform may undergo repeated cycles of renovation and upgrades. As a result, every platform element may be expected to perform far beyond the limits of its contractually defined lifetime. Extrapolations of Aging Effects (EAEs) could provide program personnel with forewarnings of potential aging platform issues. MIL-STD-810F and North Atlantic Treaty Organisation (NATO) Standardization Agreement (STANAG) Allied Environmental Conditions And Test Publication (AECTP) 600 offer tools to assist in developing EAEs. Significant changes in acquisition practices will be needed to take advantage of these opportunities.
Environmental Test Program for the Mars Exploration Rover Project
Authors: Fisher Terry , Van Velzer Paul
Published: April 2015

On June 10 and July 7, 2003, the National Aeronautics and Space Administration (NASA) launched two spacecraft from Cape Canaveral, Florida, for 6-month flights to the Red Planet, Mars. The two Mars Exploration Rover spacecraft landed safely on the planet on January 3 and 24, 2004. Prior to the successful launch, both of the spacecraft were involved in a comprehensive test campaign that included development, qualification, and protoflight test programs. Testing was performed to simulate the environments associated with launch, interplanetary cruise, landing on the planet, and Mars surface operations.

Unique test requirements included operating the spacecraft while the chamber pressure was controlled to simulate the descent to the planet from deep space, high-impact landing loads, and rover operations on the surface of the planet at 8 Torr and -130 °C (-202 °F). This paper will present an overview of the test program that included vibration, pyroshock, landing loads, acoustic noise, thermal-vacuum, and solar simulation testing at the Jet Propulsion Laboratory (JPL) Environmental Test Laboratory facilities in Pasadena, California.
Scanning Laser Vibrometer: Evaluation of an Alternative Modal Survey Tool
Authors: Brennan Sarah , Hejal Reem , Ryan Mike , Simonian Stepan , Stimson Chad , Velasco David
Published: April 2015

In preparation for the challenges presented by future spacecraft systems, we explore state-of-the-art testing technologies and compare the results to demonstrated, proven methods. A non-contact Polytec PSV-400 scanning laser vibrometer (SLV) is used to characterize the frequency response of a 2 meter reflector in a typical modal test configuration. Complementary measurements are made simultaneously using a conventional accelerometer-based system, and the results are compared to determine the effectiveness of the non-contact tool. The SLV has two distinct advantages that make it an attractive alternative for studying the structural dynamic response of lightweight, high-precision, aerospace structures—increased bandwidth (0.01 Hz-80kHz) and resolution at the nanometer scale. These features are available without modifying the structure, and they do not require labor-intensive preparation of the test article. Typical setup time is less than 1 hour. However, the one-dimensional (1D) SLV system is limited to measurement of the out-of-plane response of a surface one discrete point at a time, and it relies on software to render the global response. This differs fundamentally from a dedicated accelerometer system that may collect tri-axial information at hundreds of points simultaneously. Several different system configurations were tested, and the results, as well as lessons learned, will be presented.
New Reliability Prediction Methodology Incorporates Field and Test Experience
Authors: Nicholls David
Published: April 2015

A reliability prediction methodology is now available that addresses shortcomings in earlier models and provides for the incorporation of field and test data through Bayesian analysis techniques.
Overview of the HST Contamination Engineering Program at 15 Years: A Cleanliness Metric for Success with Optical Satellites
Authors: Hansen Patricia , Townsend Jacqueline , Hedgeland Randy
Published: April 2015

Over the past two decades, the Hubble Space Telescope (HST) contamination control program has evolved from a ground-based integration program to a space-based science-sustaining program. On-orbit, the primary contamination requirement for the telescope was maintaining a low contamination flux in the optical path of the instrument. In addition, to maintain the scientific capability of the telescope, the contamination requirements and specific contamination controls from the second- and third-generation scientific instruments and orbital replacement units were captured within the HST contamination control program. Contamination controls involving the Orbiter, astronauts, and mission were developed for on-orbit operations and four servicing missions. Long-term on-orbit scientific data has shown that these contamination controls successfully protected the HST from contamination.
Aircraft Passenger Cabin ECS-Generated Ventilation Velocity and Mass Transport CFD Simulation: Mass Transport Validation Exercise
Authors: Baker A. , Ericson S. , Orzechowski J. , Wong K. , Garner R.
Published: April 2015

A collaborative research project established between the University of Tennessee (UT) computational fluid dynamics (CFD) lab and the Federal Aviation Administration (FAA) Civil Aerospace Medical Institute (CAMI) sought to validate CFD prediction of the environmental control system (ECS)-generated ventilation velocity vector field with induced mass transport. The results of the velocity field validation exercise were published previously. An FAA Cooperative Research and Development Agreement (CRADA) project generated an experimental database of time-dependent inserted mass distributions in the CAMI Aircraft Environmental Research Facility (AERF). The companion CFD mass transport simulations were conducted at the UT CFD Lab using both commercial and proprietary computer codes. This paper reports the qualified results of the mass transport validation exercise.
Higher Yield and Quality through Particle Identification
Authors: Valet O. , Lankers M.
Published: April 2015

The sources of particulate contamination are often not easy to identify. To control manufacturing processes, the measurement of particle concentration and size is necessary and has been routinely performed for many years. Technology has been developed to increase the information available for the immediate evaluation of particles. The method analyzes airborne particles or particles isolated from liquids automatically according to their number, size, and chemical composition.1,2 The analysis of thousands of particles enables users to locate the major sources of contamination in various manufacturing processes.

The analytical tool provides rapid determination of particulate contamination, thus allowing for a quick, efficient response. Over time, the ability to compare analytical result data sets assists in detecting trends and implementing the appropriate quality management. Routine use of the technology contributes to ongoing supervision and optimization of production processes.

This study reports on the use of the technology to analyze foreign particles associated with oral, inhalable, and nasal drug products (OINDP), parenterals, and coronary stents. Applications for troubleshooting and identifying latent contamination sources are discussed through several examples.
Vibration Durability of Sn3.0Ag0.5Cu (SAC305) Solder Interconnects: Harmonic and Random Excitation
Authors: Zhou Y. , Plaza G. , Dasgupta A. , Osterman M.
Published: April 2015

In this study, the durability of lead (Pb)-free tin(Sn3.0)silver(Ag0.5)copper(Cu) (SAC305) printed wiring assemblies (PWAs) is investigated under constant amplitude, narrow-band (harmonic) excitation and under step-stress broad-band (random) excitation, and compared to the durability of Pb-based Sn37Pb PWAs. The results show that Sn37Pb assemblies last longer than SAC305 assemblies at similar excitation levels, for both harmonic and random excitations used in this study. The test specimens are identical for all tests, consisting of a PWA with plastic ball grid array components, quad flat pack components, leadless ceramic chip carriers, and leadless chip resistors. The test matrix includes test boards with different kinds of finishes and different aging conditions. Both the harmonic and random vibration tests are conducted on single-axis electrodynamic shakers. The harmonic vibration excitation is applied to a single specimen at a time, while the random vibration excitation is applied simultaneously to 20 test specimens using a specially designed test fixture. The flexural response of each test specimen mounted in the fixture is first thoroughly characterized before conducting the durability experiment. The flexural strain histories, measured on the PWAs, are used to compare the performance of the assemblies at different excitation conditions and also as inputs in other studies for stress analysis to quantify the damage in the solder joints.1 The durability tests are then conducted and time-to-failure is documented for the entire test matrix. The random durability tests are conducted at three temperatures: 125 °Centigrade (C), 25 °C (room temperature), and -40 °C. The harmonic tests are conducted only at room temperature. Destructive failure analysis (cross-sectioning, polishing, and microscopy) is conducted to confirm the failure modes. The test results presented here are analyzed in related publications1 to extract the high-cycle fatigue properties of the SAC305 and Sn37Pb solder materials.
Validation of Measured Dynamic Data Using Rigid Body Response
Authors: Smallwood David
Published: April 2015

As multiple axis vibration testing has become more widespread, it has become increasingly important to ensure the instrumentation is accurately portrayed in the instrumentation table. However, errors do occur. The method used in this paper to help uncover these errors is based on the condition that at low frequencies (below any resonant frequencies of the object being studied) the response is essentially rigid body. The spectral density matrix (SDM) at a low frequency, of many more than six response measurements, is decomposed using singular value decomposition (SVD). Under the assumption of rigid body response, it is assumed that the first six singular vectors are linear combinations of the six rigid body modes. The best linear fit is then calculated for this fit. The measurements are then removed one at a time, and the reduction in the fit error is calculated. It is assumed that if the removal of a measurement reduces the error significantly, that measurement is likely in error.
Validation of Pyroshock Data
Authors: Bateman Vesta , Merritt Ronald
Published: April 2015

This paper presents a comprehensive description of pyroshock, the interpretation of pyroshock data, and the validation of pyroshock data. Recent events in the pyroshock testing community show that corrupted pyroshock data are still being acquired at government agencies and private companies. A large part of this paper is devoted to acquisition and analysis of pyroshock data because proper time-history data acquisition and, consequently, test specification development are common industry problems. To avoid corrupted pyroshock data and thus corrupted pyroshock specifications, recommended practices for instrumentation and data acquisition systems as well as data analyses are provided. Causes of corrupted pyroshock data are explored and recommendations for avoiding corrupted pyroshock data are presented.
Financial and Operational Survey of 12 Major University Nanofabrication Facilities: A Benchmarking Study
Authors: Grimard Dennis , Jones Lisa
Published: April 2015

Efficiently running a major nanofabrication research user facility within the framework of a university is a daunting task. Operational costs, staffing, training, safety, and the diversity of the research, faculty, and users are but a few of the challenges facing the management team. This article reports on a subset of metrics used to characterize such user facilities, based on an extensive survey of 12 major university laboratories. Data relating to such factors as laboratory staffing, operating costs, subsidies, cost recovery, tuition, comparative tool rates, hours of use, and populations are summarized and reported on in the context of determining a reasonable measure of an efficient laboratory operation.
Case Study: Design and Construction of the Draper Laboratory Microfabrication Center
Authors: Morrison Richard , Racz Livia , Carter David
Published: April 2015

For 25 years, Draper Laboratory has been active in the areas of microelectromechanical systems (MEMS) and multichip modules (MCM), using two separate laboratories. When these laboratories were constructed, cleanroom technology was in its mid-life cycle. To meet evolving R&D needs, the cleanroom facilities recently underwent a major renovation as described in this article.
Discrepancies Caused by Common Industry Standard Practices Part 1: Environment Specification
Authors: Niehues John
Published: April 2015

Industry standard practices lead to discrepancies in the severity of flight and test environments. Steps in common processes defined in guidance documents are based upon assumptions and simplifications not always evident. Not acknowledging these assumptions leads to non-flight like environments in test and analysis. Documents such as MIL-STD-1540, NASA-HDBK-7005, and MIL-STD-810 all provided valuable guidance but should not be applied without consideration of underlying assumptions and simplifications. Hypothetical examples, based on real experiences, will be reviewed to illustrate the importance of understanding, modifying, or eliminating the assumptions and simplifications. The examples provided are primarily random vibration environments but the messages also apply to other dynamic environments including shock and acoustics. This paper is separated into two parts. The first addresses environment specification. The second addresses qualification and acceptance test requirements.
Avulsion of posterior primary teeth and space maintaining appliance: case report
Authors: de Carvalho Rocha Maria José , Cardoso Mariane , de Oliveira Joeci
Published: April 2015

A four-year-old child was presented to the Pediatric Dentistry Clinic of the Federal University, 21 days after an incident in which canine first and second primary molar teeth were avulsed, due to a trauma to the face. This was confirmed on radiological examination. The clinical examinations showed that tissues were normal. A removable space-maintaining dental-mucosa supported appliance was made in acrylic resin to replace the three missing teeth. After a period of eight months, the tissues were preserved, the device is helping the child to eat, to speak, and preserving the appearance of the patient. Radiograph examinations have shown that the first molar tooth and canine, first pre molar and second pre molar teeth are erupting normally. Trauma in primary dentition can cause psychological,morphological and functional problems. In the presented case the treatment was planned to recuperate the function and to avoid problems from the premature loss of primary teeth.
Hereditary gingival fibromatosis: report of three cases
Authors: Bozzo Lourenco , Naval Machado Maria Angela , de Almeida Oslei Paes , Lopes Marcio Ajudarte , Coletta Ricardo
Published: April 2015

Three cases of generalized and severe HGF in young patients of the same family without other features are reported. The purpose of this article is to present documented cases and discuss the identification, treatment, and control of the disease. The histopathological characteristics of HGF are emphasized.
Leiomyomatous hamartoma of the incisive papilla
Authors: Corrêa Luciana , Lotufo Mônica , Trierveiler Martins Marília , Sugaya Norberto , Orsini Machado de Sousa Suzana Cantanhede
Published: April 2015

A case of unusual hamartoma in a six-year-old otherwise healthy Brazilian girl is reported, with emphasis on histological and immunohistochemical features. A mass observed in the incisive papilla was detected whose appearance was similar to congenital epulis or fibroma. Histological findings showed interlacing fascicles of large spindle cells resembling smooth muscle cells. Immunohistochemical staining for desmin and for smooth-muscle actin was positive. The histological diagnosis was leiomyomatous hamartoma, based on clinical and microscopic observations.
Morphological characteristics of the deciduous teeth
Authors: Tsai Hung-Huey
Published: April 2015

The morphology of the deciduous teeth was investigated. The mean mesiodistal crown dimensions of the deciduous canine, first and second molars and the mean buccolingual crown dimensions of the deciduous second molars in both dental arches of boys were significantly larger than that of girls. The upper deciduous first molar of girls was slender buccolingually and the lower deciduous second molar of boys was slender mesiodistally.
Clinical evaluation of bonding techniques in crown fractures
Authors: Garcia-Ballesta Carlos , Perez-Lajarin Leonor , Cortes-Lillo Olga , Chiva-Garcia Fernando
Published: April 2015

The technique of bonding fragments when dental fractures occur is a routine procedure. The objective of this investigation is to demonstrate the retention of the fragments bonded using a compound material according to the Simonsen technique. The most noteworthy conclusion is that this type of restoration lasts less than two years when in the mouth. For this reason other therapeutic options with better future expectations should be introduced.
Ameloblastic fibroma: a case report in a 6 year old
Authors: Garcia-Pola Vallejo M. , Gonsalez Garcia M. , Villalain Alvarez L. , Fresno Forcedello M. , Lopez-Arranz J.
Published: April 2015

A six-year-old boy was seen by his dentist for a tumor mass in the left mandibular region. The panograph revealed a multilocular radiotransparent lesion extending from the canine to the left mandibular ascending ramus with well defined borders. After biopsy, the lesion was enucleated via curettage of the bone bed. The lesion was diagnosed as ameloblastic fibroma. After six months, radiographs showed that the surgical defect had filled with new bone.
Localization of first permanent molars in lateral cephalometric and panoramic radiographs from early mixed dentition to early permanent dentition
Authors: Tsai Hung-Huey
Published: April 2015

Changes in position and mesiodistal angulations of maxillary and mandibular first permanent molars from early mixed dentition to early permanent dentition were measured on panoramic radiographs and compared with the values measured on lateral cephalometric radiographs. It was found that the maxillary and mandibular first permanent molars were uprighted gradually, drifted mesially and vertically, and that the changes in mesiodistal angulations were clearly on the panoramic radiographs in comparison with the cephalometric radiographs.
Restoration of a fractured primary incisor
Authors: Romero Martin , Saez Manuel , Cabrerizo Carmen
Published: April 2015

Esthetic restoration on primary teeth has been a special challenge to pediatric dentists. Composite restorations are the most often used treatment for decay and fractures of primary teeth, however, there are other possible alternatives.We present a case in which we have used an acrylic crown to treat a fractured primary incisor in a 1.8 years old child.
Comparison of the behavior of children undergoing restorative dental treatment at the first visit versus the second visit in a private pediatric dental practice
Authors: Brill Warren
Published: April 2015

The purpose of this study was to determine if there was a difference in the behavior of child patients undergoing restorative dental treatment at the first office visit versus those whose first restorative treatment visit was after an initial non-threatening dental visit in a private pediatric dental practice. For patients up to and including age 9, patient behavior was recorded during the restorative session using the Sarnat scale, which rate behavior in 5 levels, from completely cooperative to completely uncooperative. Variables such as age, method of payment, referral source and sex were also recorded. The results showed that there was no statistically significant difference in the behavior of children, who had the first restorative dental experience at the initial office visit versus those children who had the first restorative procedure after a non-invasive introductory visit in all instances. There were no differences according to age, sex, socio-economic status or source of referral. It is concluded that a child may not exhibit more negative behavior as a restorative dental patient when the first visit is for restorative therapy than if the restorative treatment is delivered at a later date after a non-threatening introduction to the dental environment. Thus, a pediatric dentist need not hesitate to treat a child at the first visit for fear that it may engender more negative behavior than if the restorative dental treatment was postponed until another time.
Oral health status in Greek children and teenagers, with disabilities
Authors: Mitsea A. , Karidis A. , Donta-Bakoyianni C. , Spyropoulos N.
Published: April 2015

Nowadays there is a sharp increase of population with disabilities. The aim of this investigation was a) to survey the dental health status, estimate the treatment requirements of children and adolescents with cerebral palsy, mental retardation and visual disorders and b) to compare the oral health status of these groups of individuals. The investigation entailed the clinical examination of 170 individuals, between 6 and 15 years old, who were attending four special schools in Athens, Greece. In conclusion, our investigation documented the following: The treatment needs regarding both dentitions are extremely high in all groups of individuals. The oral hygiene status is in general, moderate to low-grade, especially in the individuals with mental retardation. The highest rate of malocclusion is observed in the group of individuals with cerebral palsy.
A comparative evaluation of oral midazolam with other sedatives as premedication in pediatric dentistry
Authors: Singh Neerja , Pandey R. , Saksena A. , Jaiswal J.
Published: April 2015

The purpose of present study was to evaluate the safety and efficacy of orally administered midazolam in children as a sedative agent and to compare it with two other older agents, triclofos and promethazine. The study was conducted on ninety child patients requiring some short dental procedure. All the patients were with a good physical status (ASA-I). The ages ranged between 3 and 9 years. The patients were randomized into three study groups: Group 1, midazolam, Group II, triclofos and Group III, promethazine, on the basis of the drugs to be administered. After administration of drugs in each group, the effects were evaluated in terms of onset of action, sedative effect, ease of treatment completion, recovery time and postoperative amnesia. Midazolam was found to be the best drug among the three to produce conscious sedation in children.
Pulpal response to different pulp capping methods after pulp exposure by air abrasion
Authors: Cardenas-Duque Lina Maria , Yoshida Makoto , Goto George
Published: April 2015

Air abrasion is regaining popularity especially in the area of pediatric dentistry due to its ease of use and its advantages. Due to the lost of tactile information, while using this technique, there is an increased risk for pulpal exposure. On the other hand, Ca(OH)2 medicament has been proven to induce dentin bridge formation, but an adequate sealing seems to be even more important that the capping material used. The purpose of this study was two fold: to assess the pulpal response after pulpal exposure by air abrasion and to evaluate the healing potential after using Ca(OH)2 medicament or Liner Bond II™ as a capping agent. Two hundred sixteen teeth from mixed-bred dogs were used in this study. The teeth were divided into three groups,A) pulpal exposure by air-abrasion followed by sealing of the cavity with Liner Bond II™, B) pulpal exposure by air-abrasion and Ca(OH)2 pulp capping and C) pulpal exposure by high-speed followed by air-abrasion and Ca(OH)2 pulp capping as a control group. The animals were sacrificed after 7, 14, 30 and 60 days and a histopathological evaluation was undertaken. After applying Analysis of Variance to compare the groups, it was observed that at earlier observation periods, the inflammatory criteria near the exposure site were different among the groups. As time elapsed, the inflammation was resolved in the pulp tissue, however, the odontoblastic layer and the dentin bridge formation had a highly statistically significant difference (p<0.001) among the various groups at all observation periods. In addition, a positive correlation was observed between the organization of the odontoblastic layer and the dentin bridge formation mainly after 30 days. It could be concluded that dentin bridge formation could be achieved with the use of Ca(OH)2 or Liner Bond II™ as capping agent with an adequate sealing. However, the formation is delayed especially when Liner Bond II™ is used as capping agent.
Retention of composite resin restorations in class IV preparations
Authors: Eid Hani
Published: April 2015

Clinicians often utilized composite resin restorations in combination with different types of preparation to restore class IV fractures on anterior incisors. A new preparation technique called (stair-step chamfer technique) is investigated in this study to detect bond strength to tooth structure. Eighty-eight bovine teeth were divided into 4 groups. Group I had twenty-three samples with a 45° bevel that extended 2 millimeters beyond the fracture line. Group II had twenty-three samples with a circumferential chamfer, which extended 2mm beyond the fracture line and half the enamel thickness in depth. Group III had twenty-three samples with a facial stair-step chamfer, which followed the anatomical contour and extended 2 mm beyond the fracture line with a lingual plain chamfer. Group IV had eighteen samples as controls,which were untreated teeth. The first three groups were prepared and restored with hybrid composite resin in conjunction with a single step bonding agent and as surface penetrating sealer, then tested for shear-bond strength on the Instron machine. The results were that there was no significant difference found between the treated teeth when tested for shear-bond strength. However, according to the site of the fracture, the stair-step chamfer technique gave significantly better results. It can be concluded that, the stir-step chamfer technique provides the clinician better environment to place a composite resin restoration resulting in good shear-bond strength and better esthetics.
Preventive effects by intensive restorative treatment against caries in children
Authors: Morinushi Takanobu , Inoue Kouichiro , Toyoshima Shozaburo , Morinushi Mayumi , Araki Yosiko , Kondo Kiyoshi
Published: April 2015

The caries preventive effect of intensive treatment of existing caries was studied in children less than 7 years old living in a district without a dentist. The methods consisted of intensive restorative treatment provided by a pediatric dentist in three stages as follows: Stage I (n=70), two years before initiation of intensive treatment; Stage II (n=80), at initiation of long-term intensive treatment, and Stage III (n=92) three years after initiation of intensive dental treatments. The results were that experience and severity of dental caries and secondary caries rates were significantly lower in stage III than in stage I or II in six year olds. Between-meal consumption of snacks containing sugar and plaque prevalence both were less in stage III than in others. In conclusion, intensive treatment of caries in young children was associated with prevention both primary and secondary caries.