bluuebunny/crossref_metadata_2025 huggingface dataset:
Alfred Selwyn - 19th Century Trans-Atlantic Connections Via Australia
Authors: Branagan D.
Published: April 2015

The contributions of A.R.C. Selwyn to geological science were considerable, and possibly unique in the 19th century, as they spanned three continents in a career lasting more than 50 years. In particular Selwyn is rightly regarded as establishing geology as a profession in Australia, both by his own high quality mapping, and by the training of a number of talented young men in his Geological Survey of Victoria (1852-1868).

In Canada he pursued the same high standards when appointed as Director of the Geological Survey at a time when the Dominion had just become greatly enlarged. A strong supporter of his staff, Selwyn engaged in a controversy with U.S. geologists about Precambrian and Lower Palaeozoic stratigraphy, maintaining that Canadian field evidence provided the key which negated the U.S. stand.

Selwyn maintained links with the colleagues of his early years in the British Geological Survey (1845-1852) during his long career, keeping in touch with new ideas in Europe and informing his friends about the results of Australian and Canadian geological research.
The Ideas of A.G. Werner and J. Hutton in America
Authors: Newcorab Sally
Published: April 2015

American geologists of the early 19th century became proficient in field and laboratory work. They read widely and were in contact with other American geologists as well as those in Europe. In the first 20 years of the century lectures in mineralogy and geology were begun, study collections formed, and laboratories and equipment became available. The ideas of James Hutton on igneous origin for rocks, and those of Abraham Gottlob Werner on rock deposition from water solution or suspension, were part of the reasoning of geologists working in America. Those geologists, as exemplified by T. Cooper, Wm. Maclure, S.L. Mitchill, A. Bruce, B. Silliman, and P. Cleaveland, added to the descriptive literature in geology, and evaluated theory from their experience.
F-16/BRU-55 Flight Vibration Data Collection Using Digital Recorders
Authors: Fling Scott , Binkley Kelly , Wrenne David
Published: April 2015

Recently a series of flight tests were conducted at Eglin AFB. Florida, using onboard, state-of-the-art digital data recorders to measure flight vibration data on the BRU-55 bomb rack. The instrumented bomb rack was flown on an F-16 aircraft under worst-case operational mission conditions. Tri-axial vibration data were recorded continuously during the flights. The raw data were then post-processed to generate power spectral density profiles for various flight maneuvers. These data were used to develop qualification test specification levels to replace the existing MIL-SID levels. This paper describes the use of the digital data recorders in collecting flight vibration data. Advantages and disadvantages of the digital recorders are discussed as compared to telemetry and tape recorders.
High-Intensity Acoustic Test Facility Using Hydraulics
Authors: Lieberman Paul
Published: April 2015

The hour-long duration acoustic fatigue tests at levels above 190 dB overall sound pressure level (OASPL) can be achieved with the required sound pressure level (SPL) spectrum using available test facilities with a hydraulic simulator, which operates at only 3 to 10 psi. Furthermore, the hydraulic control at the low frequencies is available, whereas there is a 50-Hz frequency cutoff for acoustic test facilities. Many structures have destructive low-frequency resonant modes which would be properly excited in the hydraulic facility and not in the acoustic facility.
Salvaging Pyrotechnic Data with Minor Overloads and Offsets
Authors: Smallwood David , Cap Jerome
Published: April 2015

Data are sometimes presented with serious flaws, such as saturation, over-range, zero shifts, and impulsive noise, including much of the available pyrotechnic data. Obviously, these data should not be used if possible. However, we are sometimes forced to use these data as the only data available. A method to salvage these data using wavelets is discussed. The results must be accepted with the understanding that the answers are credible, not necessarily correct. None of the methods will recover information lost due to saturation and over-range with the subsequent nonlinear behavior of the data acquisition system. The results are illustrated using analytical examples and flawed pyrotechnic data.
Force-Limiting Testing for the Small Explorer Satellite Program at NASA Goddard Space Flight Center
Authors: Kaufman Daniel
Published: April 2015

The Wide Field Infrared Explorer (WIRE) and Transition Region Coronal Explorer (TRACE) Space-craft underwent random vibration testing using force-limiting techniques as a means of controlling the vibration input motions. Interface force measurements were made for random vibration tests. Automatic force feedback notching was provided for the random vibration tests. This paper presents the methods employed to determine force spectrums. Test results are presented to show the effects of the force-limiting technique.
Preliminary Design Procedures for Equipment Exposed to Random Vibration Environments
Authors: Piersol Allan
Published: April 2015

A New NASA Handbook presents recommended procedures for the preliminary and final design of equipment items exposed to various dynamic loads, including random vibration excitations.1 For the final design when the geometric details of the equipment items have been largely determined, finite element method (FEM) and statistical energy analysis (SEA) procedures can be employed to predict the maximum stresses in equipment items due to random vibration excitations at their mounting points. In the preliminary design phase, however, more approximate prediction techniques are often needed, as summarized in the Handbook. The purpose of this paper is to detail the rationale behind these preliminary procedures. Included are simple techniques to predict a maximum instantaneous stress during a short duration vibration environment and fatigue damage during a long-duration vibration environment, based only upon estimates for the frequency and damping ratio of the first significant resonance of the equipment.
Measurement of Electrical Properties of Cleanroom Gloves
Authors: Newberg Carl
Published: April 2015

This paper outlines the different methods used to characterize the electrical properties of cleanroom gloves used in electrostatic discharge-protected areas. A review of the currently used test methods and specifications will be covered, along with a discussion of the many problems and pitfalls associated with interpretation and application of those test methods and standards.
Planning Climatic Tests Using Physics-of-Failure Principles and Empirical Models
Authors: Sherf Z. , Hopstone P.
Published: April 2015

When one faces the need to plan a climatic test (temperature, temperature-humidity, rain, solar radiation etc.), several options are available. The most frequently implemented option is the use of standards. Often, the use of standards leads to testing programs that do not reflect the system's life cycle, or that prevent differentiating between systems with different life cycles. This is true even for standards that implement the tailoring philosophy. How can climatic tests be tailored to reflect true life time such as 10,000 hours or 100,000 hours? A methodology that makes use of physics-of-failure principles and empirical models provides a more realistic solution to this problem. Using empirical models to describe the environmental loads, and damage accumulation models under different loads, the effects of real life can be simulated and compared with the effects of the simulated testing conditions. The paper describes the use of this methodology. Empirical models are used to describe diurnal thermal and humidity cycles. An empirical model of temperature distribution is applied to determine the duration of exposure to varying temperature during a given life cycle. Several damage accumulation models under cyclic thermal loads are compared. One is a general power model with changing exponents for different materials. An additional model relates to the behavior of solder joints. The application of the models is compared for two different conditions, one for which the different daily temperature changes are considered, and one for which monthly average temperature changes are used to describe the daily conditions for a certain month. To evaluate temperature-humidity tests, models that describe corrosion damage under temperature-humidity and humidity penetration models are implemented to evaluate the effects of the testing conditions, relative to the real life. The advantages and problems in the implementation of the methodology are discussed in the summary of the paper.
The Effects of Ambient Differential Pressure on Minienvironments, Isolation Enclosures, and Laminar Flow Devices
Authors: Walters John
Published: April 2015

This paper will discuss various differential pressure situations, and the ramifications of negative differential pressure. Empirical data will be used to illustrate the anomalies that occur when less than optimal differential pressure conditions exist. The paper will also differentiate between "ballrooms" and "bay and chase" cleanrooms and the effects of isolation enclosures on tools in varied conditions. The purpose of this paper is to educate the reader on airflow optimization for increased facilities performance.
Codes and Standards Resource for Semiconductor Fabrication Facilities
Authors: Hailer Jason , Chasey Allan
Published: April 2015

The CREATE Codes and Standards Resource for semiconductor facility design, construction, and commissioning is an effort to compile all codes and standards relevant to the semiconductor industry. The CREATE Codes and Standards Resource is designed to easily guide the semiconductor EHS professional through the various codes, standards, and specifications that have a direct impact on the facilities, both in the operations and on the individuals. Links to other known resources, as well as topics that should be considered from an EHS standpoint, are available in a web-based portal for ease of access and for dissemination of the data.
Ozone Production by Corona Discharges
Authors: Noll Charles
Published: April 2015

Ozone entertainment has been measured for point-to-plane corona electrodes in an insulating flow channel. Electrodes with 16 mm point-to-plane spacing were set at AC and positive/negative DC voltages and exposed to gas flows from 0.3 m/s to 3.3 m/s in air. The ozone yield in grams per coulomb (g/C) of charge transferred in the discharge was found to be constant, yet with different values for the various modes of corona.
A Family of Transients Suitable for Reproduction on a Shaker Based on the cosm(x) Window
Authors: Smallwood David
Published: April 2015

A family of transients with the property that the initial and final acceleration, velocity, and displacement are all zero is derived. The transients are based on a relatively arbitrary function multiplied by window of the form cosm(x). Several special cases are discussed which result in odd acceleration and displacement functions. This is desirable for shaker reproduction because the required positive and negative peak accelerations and displacements will be balanced. Another special case is discussed which will permit the development of transients with the first five (0-4) temporal moments specified. The transients are defined with three or four parameters that will allow sums of components to be found which will match a variety of shock response spectra.
Clean Construction Protocol for the National Ignition Facility Beampath and Utilities
Authors: Sommer Stanley , Stowers Irving , Van Doren David
Published: April 2015

When the stadium-size National Ignition Facility (NIF) is fully operational at the Lawrence Livermore National Laboratory (LLNL), its 192 laser beams will deliver 1.8 megajoules (500 terawatts) of energy onto a target to create extremely high temperatures and pressures for inertial confinement fusion research as part of the Stockpile Stewardship Program. Due to the performance threshold and requirements of the NIF optical components, the optics and their surrounding beampath as well as the supporting utility systems must be fabricated, cleaned, assembled, and commissioned for precision cleanliness. This paper will provide an overview of the NIF cleanliness requirements, the Clean Construction Protocol (CCP) specifications for the beampath and clean utilities, and techniques for verifying the CCP specifications.

The NIF cleanliness requirements define limits for molecular and particulate contamination. The goal of these limits is to prevent contamination of optical components. To prevent laser-induced damage and poor laser quality in the optical components, requirements for cleaning, assembly, installation, and commissioning in terms of particle and nonvolatile residue (NVR) levels are defined. The airborne cleanliness requirements in the interior of the beampath are Class 1 (ISO Class 3) particulate levels and a few parts-per-billion (ppb) airborne molecular contamination (AMC) (SEMI F21-95 MC-1,000).

To achieve the cleanliness requirements for the beampath interior, a graded CCP approach is used as the NIF beampath and utilities are being constructed by a partnership between LLNL and the construction contractor, Jacobs Facilities Inc. (JFI) in a stadium-size Class 100,000 (ISO Class 8) building. Installation of the beampath components utilizes localized mini-environments of Class 100 (ISO Class 5) or better, with budgets of cleanliness exposure or "class-hours" for each clean connection. Garment, equipment, and operational considerations are evaluated with process verification.

Verification of the beampath and utility cleanliness is performed with cleanliness exposure monitoring, evaluating particulates with "swipes" and the LLNL-developed Precision Cleanliness Verification System (PCVS), and measuring nonvolatile residues (NVRs) and AMCs with analytical chemistry techniques. Cleanliness verification results demonstrate that the CCP specifications are achieving the NIF cleanliness requirements for the beampath and clean utilities.
Laboratory Evaluation of Fan-Filter Units' Aerodynamic and Energy Performance
Authors: Xu Tengfang , Jeng Ming-Shan
Published: April 2015

Use of a consistent testing method is beneficial is characterizing aerodynamic and energy performance of fan-filter units (FFUs). Evaluation methods of laboratory-measured performance for ten relatively new, 1220 mm × 610 mm (or 4 ft × 2 ft) FFUs are presented. The paper includes results such as energy performance indices (EPI) based upon the sample FFUs tested. This paper concludes that there are variations in FFU performance, and that using a consistent testing and evaluation method can generate compatible and comparable FFU performance information. The paper also suggests that benefits and opportunities exist for integrating this method of testing FFU energy performance into future recommended practices.
A General Process for Defining Product Durability Requirements
Authors: Aldridge Dustin
Published: April 2015

An overview of the major steps involved in estimating product durability requirements using available data is presented with execution examples of the process as applied to vehicles.
Statistically Significant Efficiency Testing of HEPA Filters
Authors: Wang Wenli , Winters Philip
Published: April 2015

High Efficiency Particulate Air (HEPA) filter manufacturers must ensure the accuracy of efficiency testing for these filters and, at the same time, keep productivity at a reasonable level. This study describes tests conducted to determine the minimum time required to provide statistically significant efficiencies of HEPA filters using a test system currently in use of HEPA filter production.

The test results of over 300 HEPA filters were analyzed in this study. The approaches in IEST RP-CC-007.1: Testing ULPA Filters for statistical analysis of particle counts were followed. A Poisson distribution was used to describe the variations and to calculate the lower and upper limits of measured counts at 95% confidence level. This study shows that 90 seconds is sufficient for this test system to determine whether a HEPA filter has an efficiency of 99.990% or higher at 95% confidence. Longer tests will cause the mean measured efficiency to approach the filter's true efficiency and also narrow the confidence interval. However, challenging HEPA filters made of glass fiber media with oil aerosols for up to one hour does not significantly change the filter's true efficiency performance.

The preferred approach for a new test system is to use software that calculates the confidence limits of filter efficiency after each sampling cycle and determines whether to continue testing. For an existing system without this type of program (such as the one evaluated in this study), analysis is necessary to make sure the HEPA filters are challenged with enough aerosol particles.
Mars Exploration Rover (MER) Airbag Retraction Actuator (ARA) Pyroshock Test Results
Authors: Chang Kurng
Published: April 2015

This paper presents the shock test results achieved in the Mars Exploration Rover (MER) airbag retraction actuator (ARA)/brush motor pyroshock qualification. The results of MER flight system pyrofiring tests are compared with ARA shock test requirements. Alternate test methods were developed in an effort to qualify critical MER equipment for adequate performance under actual flight pyroshock conditions. Simulated pyroshock qualification tests were conducted using shakers, mechanical impacts, and explosive charges for excitation. Comparisons of excitation and responses of an ARA subjected to different shock tests are presented.
A Novel Approach to the Dynamic Balancing of Spun/De-spun Spacecraft
Authors: Montgomery John , Haynes Robert
Published: April 2015

In response to challenges encountered in the dynamic balancing of the Windsat instrument, a novel approach to dynamic balancing of dual-spin spacecraft was developed. The Windsat instrument is a 675-lb microwave radiometer consisting of a small, 200-lb stationary module topped by a large rotating truss structure approximately nine feet in height. A 72-in.-diameter reflector atop the truss, designed to direct microwave energy into the Windsat radiometer, was a significant source of aerodynamic lift and drag during spin balance testing. The approach developed in this study allows the spacecraft integrator to balance the vehicle while spinning under its own power and about its own spin axis. This balancing system is also capable of operating in a vacuum environment, thus eliminating aerodynamic forces that result in test-induced errors. The balancing system consists of a two degree of freedom (DOF) suspension system similar to that found in conventional balancing machines. Unbalance forces and moments are reacted through two piezo-electric force transducers, the outputs of which are recorded using a vibration lab data acquisition system. To prove viability, a prototype of this system has been developed and integrated into existing Naval Research Laboratory (NRL) spacecraft vibration test facilities. Using existing instrumentation and data acquisition systems, extensive experimentation with this system prototype has demonstrated this concept to be viable, yielding results that agree closely with analytical predictions.
Using Expanded QFD Matrix Analysis to Establish and Link Test Instrumentation to Customer Satisfaction Attributes
Authors: Plotkin Charles , Moon Kee
Published: April 2015

When reliability testing is performed, the focus is often on engineering metrics such as changes in part dimension or material properties that are of interest to the design engineer. This focus can result in missing failure or degradation conditions that affect customer satisfaction with the product. There is a need for a structured approach to plan the test, engineering metrics, and measurement system (instrumentation) on product or system attributes that contribute to customer satisfaction. This paper shows how a simple needs-metrics matrix (a common element used in Quality Function Deployment or QFD) can be expanded to serve as a structured tool to establish laboratory test instrumentation for objective measurements in a reliability test. This paper also shows how the matrix can be further expanded to include results of interim subjective evaluations. This expanded matrix can then be used to readily relate the results of reliability testing as well as subjective testing to potential impact on customer satisfaction.
Practical Application of ISO Cleanroom Standards
Authors: Dixon Anne
Published: April 2015

The original work of ISO Technical Committee (TC) 209 Cleanrooms and associated controlled environments is nearly complete. When the TC sat down in 1993 to begin developing a set of international standards, members could not have predicted all of the benefits these standards provide.
IEST Focuses on Facilities in Nanotechnology Initiative
Authors: Ensor David
Published: April 2015

As interest grows in the design, construction, and operation of nanofacilities for R&D and manufacturing, IEST addresses the question: What does it take to do nanotech work?
Use of Ultrasonic Cavitation in Surface Cleaning: A Mathematical Model to Relate Cleaning Efficiency and Surface Erosion Rate
Authors: Nagarajan Ramamurthy
Published: April 2015

Ultrasonic cleaning, employing frequencies in the range of 40-200 kHz, is widely used in many industries requiring precision cleanliness in the micrometer to submicron particle size range—e.g., semiconductor wafer fabrication, hard disk drive manufacturing, and integrated circuit assembly. One overriding concern with the use of ultrasonic cleaning for delicate components and assemblies has been the specter of cavitation erosion—surface material loss and other functional degradation due to the impact of shock waves generated by collapsing bubbles and bubble clusters in an oscillating acoustic field. The simultaneous processes of surface cleaning and surface erosion in the presence of a high-frequency ultrasonic field (⩾ 58 kHz) are described here mathematically, and the equations are coupled to allow conceptual optimization of parametric settings to maximize cleaning efficiency while minimizing the level of erosion damage. This theoretical analysis is presented for various ultrasonic field conditions (frequency, intensity, etc.), fluid medium properties (viscosity, density), and surface conditions (hardness, smoothness, etc.). The contribution of acoustic streaming to surface cleaning is incorporated in the model, and is shown to have minimal influence on the optimum cluster collapse pressure, but to have a significant effect on the net cleaning efficiency for the surface.
Control of an Over-Actuated Single-Degree-of-Freedom Excitation System
Authors: Hale Michael , Fitz-Coy Norman
Published: April 2015

This paper provides results of a laboratory experiment designed to illustrate the theoretical control considerations for an over-actuated excitation system. The experiment is based on control of a beam pinned at one end providing a single rotational degree of freedom and excited by two electrodynamic actuators. Control is achieved through implementation of two different control reference techniques: (1) reference based on linear acceleration autospectral densities (ASD) and cross-spectral densities (CSD) using linear accelerometer feedback and (2) reference based on an angular acceleration ASD using estimates of angular acceleration as feedback. Correlations to the theoretical based predictions were conducted based on common measurements of both linear acceleration and estimates of angular acceleration acquired during each trial.
Fatigue Margins Established by Unit and Spacecraft Protoqualification Tests
Authors: Pierre-Louis Enold
Published: April 2015

Protoqualification (PQ) testing, typically performed on the first assembled electronic units and spacecraft, establish random vibration and thermal cycling fatigue margins for subsequent builds that are only subjected to the acceptance test program (ATP). Considering the fatigue damage induced by both unit- and spacecraft-level testing, fatigue margins are calculated for equipment exposed to ATP-level testing. Probabilistic analyses are also performed to determine the relationship between the fatigue margin and the demonstrated reliability for the unit to survive the mission. Parameters such as the number of retests and the material dependent fatigue acceleration exponent are considered.

Using MIL-STD-1540E,1 PQ random vibration test guidelines of three decibels (+3 dB) above the acceptance input level for 2-minute-per-axis duration, the assessment shows that the test establishes ample fatigue margin for units subjected to the less stringent ATP. The probabilistic analysis shows that the established reliability to survive the launch environment without a fatigue induced failure is adequate. It is further shown that the desired high-cycle fatigue life factor of greater than four is maintained even after one unit retest is performed. However, since this conclusion is general in nature, it is important that for future spacecraft, assessments be performed for both PQ and ATP hardware, taking into account each specific design and application to verify that adequate fatigue margin exists to survive launch.

Because mission thermal cyclic environments vary greatly with regard to the number of cycles and the extent of the thermal range for each cycle, MIL-STD-1540E PQ guidelines for unit-level testing were designed to verify the design and workmanship and not intended to demonstrate fatigue margin for specific missions. Rather, MIL-STD-1540E specifies that thermal cyclic fatigue margin for the combination of pre-launch and orbital environments should be demonstrated with life testing. Accordingly, the analysis shows that PQ testing only demonstrates the desired low-cycle fatigue life factor of 2 for subsequent units which are subjected to a single ATP. The fatigue life factor falls below 2 when retests and/or mission thermal cyclic environments are considered. Because acceptable fatigue margin is not established with the standard PQ thermal cycle test procedure, it is essential that other means be taken to ensure that adequate fatigue margin exists. This paper provides guidelines for using analyses and offline life testing to assess the fatigue life of critical units and their internal components for pre-launch and orbital thermal cyclic environments.
Utilizing the Generalized Linear Mixed Model for Specification and Simulation of Transient Vibration Environments
Authors: Merritt Ronald
Published: April 2015

Transient vibration environments are an important consideration in qualification of aircraft store components — particularly for aircraft with internal storage bays. Generally, these transient vibration environments provide high stimulus input to a store via aerodynamic forces for up to 15 seconds on numerous occasions during training. With the recent introduction of the technique of Time Waveform Replication (TWR) to laboratory testing (MIL-STD-810G Method 525), store components can be readily tested to replications of field-measured transient vibration environments. This paper demonstrates the use of the Generalized Linear Mixed Model (GLMM) on a collection of measured field responses for specification of transient vibration environments. The paper establishes a basis for moving from (1) transient vibration measured field response to (2) transient vibration stochastic specification of the measured field response to (3) laboratory simulation of transient vibration environments.
Sampling Plan for Cleanroom Classification with Respect to Airborne Particles
Authors: Hartvig Niels , Farquharson Gordon , Mielke Robert , Varney Mark , Foster Mike
Published: April 2015

The concentration of airborne particles is a critical parameter for cleanrooms, clean zones, and controlled areas. Particle concentration must be measured at representative locations for classification and monitored routinely or continuously at critical locations during operation. Both ISO 14644-1:19991 and the new Draft International Standard (DIS) edition provide nine classes of cleanliness and specify both the number of sample locations for classification and the acceptance criterion for the data.

In the 1999 version of the Standard, the minimal number of sample locations is not based on statistical principles. The acceptance criterion is based on a statistical test, but only if the number of sample locations is less than 10. Thus, classification is based on statistical methods only for a small number of locations.

The revised ISO/DIS 14644-12 replaces this method with a statistical principle for selection of the sample locations. The acceptance criterion in the revised version eliminates the need for applying a statistical test to the data, and thereby simplifies the classification process.

The purpose of this paper is to present and discuss the new sampling plan for cleanroom classification and compare it with the previous approach in ISO 14644-1:1999. Section 2 of this paper presents and discusses the previous method, section 3 describes the new method in the ISO/DIS 14644-1 revision, and section 4 provides a discussion and conclusion. All of the authors are members of ISO Technical Committee (TC) 209, Working Group 1, the group of experts who developed the new ISO/DIS 14644-1. This paper was written on behalf of the entire Working Group.
A 6-DOF Vibration Specification Development Methodology
Authors: Hale Michael
Published: April 2015

Multiple degree of freedom (MDOF) excitation systems and MDOF vibration control systems continue to improve, and are now standard equipment in many dynamic test laboratories. This paper concentrates on the often overlooked process of determination of an input specification for such MDOF systems. A pair of generalized six-degree-of-freedom (6-DOF) vibration specification development (VSD) techniques are proposed, discussed, and illustrated through an example.
Highly Accelerated Life Test (HALT) Program at Space Systems Loral
Authors: Kosinski Brian , Cronin Dennis
Published: April 2015

Highly Accelerated Life Testing (HALT) is used in the commercial electronics industry to improve product robustness prior to starting production. The basic theory is that testing well beyond expected, intended-use environments may uncover design flaws that could become field failures after a product is in production. By fixing issues prior to starting production, costly recalls can be avoided. HALT has proven to be effective, as evidenced by its wide incorporation in the commercial electronics industry. Could HALT also be worth the time and expense of performing on commercial satellite hardware, which is designed to rigorous standards and tested over military-grade environmental test specifications? This paper summarizes Space Systems/Loral's (SS/L) initial experience with HALT, experience over time, and refinement of the traditional HALT process with emphasis on finding the operating limit margins before purposely searching for any failure limits. The methodology used by SS/L has proven to be effective when introducing new technologies and complex designs for use on commercial satellites.
Evaluating Aerosol Transmission Efficiency in a Sampling System
Authors: Liu De-Ling
Published: April 2015

This work examines the physical factors that contribute to sampling errors in an aerosol sampling system consisting of a sampling probe and a sampling line. Aerosol particles are more massive than gas molecules and therefore tend to deviate from air streamlines in response to sudden directional change, which potentially leads to sampling errors during sample transfer processes. Based on well-established studies involving particle transport and deposition, an analysis was performed to determine the sampling line transmission efficiency for 0.5- and 5-μm particles as these particle sizes are used in defining air cleanliness level in ISO 14644-1[1] and FED-STD-209E.[2]* Our analytical results indicate that significant particle losses for 5-μm particles can occur if bends exist in the sampling lines. In addition, particle losses typically can be reduced by lowering the air velocity in the sampling line, and this can be achieved by using a sampling line with a larger inner diameter (I.D.). The example calculations also showed that 0.5-μm particles, with their insignificant inertia, have nearly 100% transmission efficiency regardless of the sampling line bends.
Evaluation of Vibration References with Equivalent Kurtosis and Dissimilar Amplitude Probability Densities
Authors: Hale Michael , Barber William
Published: April 2015

The generation of Gaussian noise with a specific auto spectral density (ASD) is a well-documented process employed in drive signal generation in vibration control applications. In recent years, vibration control system vendors have introduced the ability to modify the probability density function (PDF) characteristics associated with the reference ASD, yielding a non-Gaussian drive. The specific parameter defining this process is kurtosis. This paper will discuss concerns with this practice in terms of synthesizing a time history with dissimilar PDF characteristics to that of the measured data upon which the original ASD and kurtosis characteristics were based. An example is discussed from both statistical and fatigue perspectives.
Ferric sulfate as pulpotomy agent in primary teeth: twenty month clinical follow-up
Authors: Ibricevic Hamijeta , Al-Jame Qumasha
Published: April 2015

Seventy primary molar teeth, carious exposed, symptom free, without any sign of root resorption in children aged from 3 to 6 years (main age 4.3yr) were treated with conventional pulpotomy procedures. Ferric sulfate 15.5% solution (applied for 15 second for 35 teeth) and formocresol solution (five minute procedure of Buckley's formula for next 35 teeth) have been used as pulpotomy agents. In both groups, pulp stumps were covered with zinc-oxide eugenol paste. Permanent restorations were stainless steel crowns. Clinical check up was every three-months and radiographic follow-up time was six and twenty months after treatment. Our results within this period revealed 100% clinical success rate in both groups. Radiographic success rate was in both groups 97.2%, while in 2.8% cases has shown internal root resorption. On the basis of these results, we can recommend ferric sulfate as a pulpotomy agent in primary teeth in substitution for formocresol at the moment.
Short term human primary pulpal response after direct pulp capping with fourth-generation dentin adhesives
Authors: Cehreli Zafer , Turgut Melek , Olmez Seval , Dagdeviren Attila , Atilla Pergin
Published: April 2015

The purpose of this study was to evaluate the effects of the total-etch and direct pulp capping techniques on the short-term response of mechanically exposed human primary tooth pulps using three commercially available adhesive resin systems. Class V cavities were prepared on the buccal surface of intact mandibular primary molars and exposed with a carbide bur on the cavity floor. The entire cavity except the exposure site received 36% phosphoric acid gel conditioning. Exposed pulps were capped with one of the three adhesive resins, followed by restoration of the cavities with the respective restorative materials. The teeth were extracted after 60 days and prepared according to normal histological techniques. Serial sections were stained with H/B for histological evaluations. The histopathological evaluation showed that a few of the samples in the Scotchbond Multi Purpose (SMP) and Prime & Bond 2.1 (PB) groups exhibited "attempted bridge formation", while no bridge formation was evident in the other samples. Syntac Single Component (Syntac) exhibited the most severe histological response, while the mildest reactions were observed in the SMIP group. Based on the conditions of the present study, direct pulp capping with dentin bonding agents following the total-etch technique in primary teeth can not be recommended.
Pulpal evaluation of two adhesive systems in rat teeth
Authors: Cortés Olga , García Carlos , Bernabé Antonio
Published: April 2015

Formocresol is the agent most frequently used with pulpotomies in primary teeth, but its use is currently under discussion in regard to its possible toxic effects. Some current works suggest the use of dentinal adhesives in cavities with minimal dentinal thickness and even in small pulpal exposures. Our objective was to evaluate pulpal response to the application of two dentinal adhesives Syntac® and Prime & Bond NT® in pulpal exposures in rat teeth. Sprague Dawley rats were used, male, 150 to 200gm in weight. The maxillary first molar, left and right, was employed in each case, a total of twelve teeth. Duration of the study was 45 days. Sections were evaluated using a light microscope in order to determine pulpal response to the two adhesives. In both groups the persistence of chronic inflammation was associated with the absence of dentinal bridges in the affected specimens. Areas of necrosis and absence of regularity of the odontoblastic layer could also be seen.
A rare non-syndrome case of concomitant multiple supernumerary teeth and partial anodontia
Authors: Sharma Amita
Published: April 2015

Concomitant hypo-hyperdontia is an uncommon condition of coexistence of partial anodontia and supernumerary teeth. Its etiology is still unknown. Very few cases have been reported in the literature of this condition. Presented here is a rare and first such case of simultaneous presence of multiple supernumerary teeth and a missing tooth (canine) without any associated systemic conditions or syndromes involving both jaws.
Clinical features of incontinentia pigmenti with emphasis on dermatoglyphic findings
Authors: Tanboga Ilknur , Kargul Betul , Ergeneli Semra , Aydin M.Yalcin , Atasu Metin
Published: April 2015

Incontinentia pigmenti is a syndrome characterized by both systemic and oral manifestations. Presented here are the dental, clinical, radiological, genetic and dermatoglyphic findings of a 6 year old female case and her family members. The following features were apparent: oligodontia in maxillary and mandibular arches in both dentition, peg-shaped incisors and brown lessions on the body surface. No other problems were observed. The case had remarkable dermatoglyphic findings such as hypothenar loops associated with distally displaced axial triradii on both palms, reduced total finger and summed palmar a-b ridge-counts, decreasing plantar pattern intensity on the left sole. The other family members had similar dermatoglyphic characteristics. The paternal grand father, the father and the brother had eye defects.
Dentoalveolar response after protraction mask and expansion in males and females in the mixed dentition
Authors: Saadia Marc , Torres Edgar
Published: April 2015

The purpose of this study was to determine the dentoalveolar response of class III patients in the mixed and late mixed dentition phases fitted with a protraction mask and expansion. The before and after cephalometric records of 74 patients divided by sex were analyzed at ages 6 to 9 and 9 to 12 years to assess the dentoalveolar changes. Data was correlated by means of paired t tests and Scheffe's multiple contrasts. No significant changes were seen in all dentoalveolar relationships between the ages of 6 to 9 years and 9 to 12 years and between males and females. Maxillary teeth tended to be proclined, while mandibular teeth to become retroclined.
The relationhip between occlusal factors and bruxism in permanent and mixed dentition in Turkish children
Authors: Sari Saziye , Sonmez Hayriye
Published: April 2015

The aim of this study was to investigate the relationship between occlusal factors (overjet, overbite, Angle's Classification of molars and cuspids, the relationship of the primary molars, openbite, lateral openbite, scissorbite and crossbite) and bruxism in permanent and mixed dentition in Turkish children. For this reason 182 children with mixed dentition and 212 children with permanenth dentition were included in this study. Occlusal conditions were examined clinically and bruxism was assesed by using interview and questionnaires. Z Test was used to compare the results. It was found that in both dentition some occlusal factors related with bruxism (overjet > 6 mm, overbite > 5 mm, negative overjet, openbite in permanent dentition; overjet > 6 mm, overbite > 5 mm, scissorbite, anterior-posterior multiple teeth crossbite, Angle Class I occlusion in mixed dentition.
Eruption disturbances of mandibular permanent incisors
Authors: Watanabe Celso Tadao , Watanabe Jun-Ichi , Taguchi Yo , Noda Tadashi
Published: April 2015

In this study, we analyzed 7 eruption disturbance cases of mandibular permanent incisors (5 males and 2 females), aged 5y9m to 10y4m. The etiology was divided into 3 categories: traumatic injuries (3 cases), odontomas (2 cases), supernumerary teeth (2 cases). The procedures such as removal of cause (4 cases), surgical exposure (5 cases) and traction (1 case) were done.
Autistic children: experience and severity of dental caries between 1980 and 1995 in Kagoshima City, Japan
Authors: Morinushi Takanobu , Ueda Yasuhiro , Tanaka Chihoko
Published: April 2015

The present study indicates that experience and severity of dental caries in 1995 showed a clear decrease from observations in 1980 in Kaogsima City, Japan. This decline may be attributed to several factors such as the qualitative and quantitative improvements in treatment of caries, more regular visits to dental clinics, improved daily oral hygiene, and changes in dietary pattern.
Evaluation of visual, explorer, and a laser device for detection of early occlusal caries
Authors: El-Housseiny Azza , Jamjoum Hana
Published: April 2015

Reliable early diagnosis represents the keystone in modern dental care. This study aimed at disclosing a correlation between length of experience by the dentist and accuracy of caries diagnosis, by traditional clinical technique, that included visual and explorer examination, and evaluating the accuracy of the DIAGNOdent laser device. Histological sections confirmed clinical data obtained. Results showed that a reverse relationship between length of experience and accuracy of caries diagnosis i.e. younger dentist could achieve more accurate diagnosis. Laser diagnosis was superior to clinical diagnosis, whether by vision or explorer. It is concluded that DIAGNOdent laser is a promising instrument that can represent a valuable contribution to the dental practice.
Oral manifestations of congenital neutropenia or Kostmann syndrome
Authors: Defraia Efisio , Marinelli Andrea
Published: April 2015

Infantile congenital agranulocytosis or Kostmann syndrome is a rare hereditary kind of severe neutropenia. The typical symptoms, which appear since the first days of life, are abscesses located on various parts of the body: ear, cutis, lung and oral cavity. These abscesses are due to an almost total disimmunity typical of the neutropenia.

The aim of this article is to describe the most typical signs of this pathology in the oral cavity, reporting a case observed in our department in Florence, Italy. On the basis of the personally observed case and of the review of the literature, it is possible to consider, as a characteristic finding in Kostmann syndrome, a typical very serious periodontal pathology, which is similar to the prepubertal periodontitis in deciduous dentition. At the age of 19 years the patient showed a dramatic compromise of the masticatory function.

It is obvious that the lack of response of the host can obstruct the interaction between the host and the microbic flora, because the lack of neutrophils increases the susceptibility of the patient to every kind of infection, even to periodontitis. A periodontal prophylaxis, since the very first observations, followed by a rigorous maintenance with frequent and regular professional hygienic treatments could be effective in controlling the effects of periodontal disease and could reduce the tragic evolution. We need to recognise that it could be hard to monitor the oral situation correctly in these patients, as they have a continuously poor systemic condition. Finally in these cases the rehabilitative therapy is very problematical.
Salivary Streptococcus mutans and lactobacillus sp levels in cardiac children
Authors: Torres M.C. , Ramos M. , Coelho T. , Harari S.
Published: April 2015

This study assesses salivary conditions of 20 children with cardiac disease comparing with a control group of 15 healthy children. The results showed that there was no difference between the groups on salivary flow, buffer capacity and the level of Streptococcus mutans (Sm). The test group i.e., children with cardiac disease, showed a lower level of Lactobacillus sp. The association between the usage of antibiotics and the risk of developing caries, measuring the level of Streptococcus mutans and Lactobacillus sp., showed that children taking antibiotics frequently had a significant lower level of Lactobacillus sp (p<0.05) than healthy children. This association was not found on relation to the levels of Streptococcus mutans.
Conscious sedation in the 21st century
Authors: Eid Hani
Published: April 2015

Most (99%) patients treated at this university clinic do not need any form of sedation as rapport and behavioral management skills are more than sufficient and are safe. Those aged 1 to 5 years, who needed the use of oral sedation (Midazolam), showed 70% success. Those who needed nitrous oxide / oxygen ranged in age from 8 to 18 years and were later treated without any sort of conscious sedation after one or two sessions of nitrous oxide / oxygen sedation.
Combining functional appliances in the straightwire system
Authors: Mahony Derek
Published: April 2015

The Trainer for Braces (T4B) helps speed up fixed appliance therapy, by derotating teeth and pushing them into the line of the arch. It also aids treatment stability by reducing the influence of undesirable myo-functional habits and retraining the oral musculature. I issue a T4B to all my patients on the day of bracket placement. I have noticed a 30% reduction in treatment times for those patients who wear the T4B as directed.
Density and diameter of dentinal tubules of first and second primary human molars - comparative scanning electron microscopy study
Authors: Ruschel Henrique Castillhos , Chevitarese Orlando
Published: April 2015

The aim of the present survey was to evaluate tubule density and diameter of dentin of first and second primary human molars and compare the two dental categories. These evaluations were done solely at the middle third of the crowns of twenty extracted noncarious teeth separated in two groups (first molars and second molars). The tubule diameters observed were 0.794μm and 1.0μm for first and second molars, respectively (measurements done at 35-65% from the pulp-chamber walls). Regarding tubular density, the measurements indicated 17,997.594 tubules/mm2 and 25,211.317 tubules/mm2 for first and second molars, respectively. Comparisons between-groups indicated that tubule diameter and density of dentin were higher in second molars, being the difference highly significant (P<0.01).
Ewing's sarcoma of the mandible: a combined approach to treatment
Authors: Fielding Allen Fred , Lindemeyer Rochelle , Wood-Harris Julie , Hartman Michael
Published: April 2015

Ewing's Sarcoma (ES) is a malignant tumor, which arises primarily in children. Most commonly found in the long bones and pelvis, it rarely is found in the bones of the face. This is a report of ES of the mandible in a nine-year-old Caucasian female. Treatment for this malignancy included an incisional biopsy, chemotherapy and radiotherapy protocol to the involved area in accordance with St. Christopher's Hospital and the Children's Hospital of Philadelphia. The patient is currently diseasefree and has been for approximately five years.