Materials Considerations for Improved Flash/Flame Protection

2009 ◽  
Author(s):  
Jeremy D. Paquin ◽  
Francisco J. Martinez ◽  
Joseph Hitt ◽  
A. O¨zer Arnas
Keyword(s):  
Radiant Energy ◽  
Burn Injuries ◽  
Background Information ◽  
New Materials ◽  
Current Configuration ◽  
Design Characteristics ◽  
Materials Used ◽  
Full Scale Tests ◽  
Alternative Choice ◽  
Fire Resistant Material

To investigate the capabilities of protective clothing materials to withstand the initial radiant energy effects and secondary flame impingement from a blast and devise suggestions for new materials, better configuration designs, and manufacturability of those designs must be considered. This paper discusses results that will directly benefit soldiers and others with risk to exposure of flash/flames due to explosions. Dismounted soldiers need a material that has improved flash/flame protective qualities to better protect them in combat situations that may result in burn injuries from fires that originate from a blast. This paper investigates why the burns occurred, how the materials used in the current configuration of clothing could be improved upon, and what new materials choices can be made in other configurations to better protect dismounted soldiers. The causes of failure have been evaluated, and by way of reverse and forward engineering, alternative choice of materials and improved designs has been considered. As a result, a prototype can/will be built based on the design characteristics, tested, and potentially fielded for use by soldiers. The paper provides sufficient background information on the anatomy of explosions, physiology of burn injuries, and blast type and burn relationships. Current testing methods for testing burn-protection materials are discussed including both bench scales and full scale tests and the pros and cons of each. The engineering requirements for current fire resistant clothing are broken down. Then, a description of the assumptions is listed, and the engineering design process is applied to the problem to determine which characteristics are most important in this type of fire-resistant material. This process includes a survey and several design tools to narrow the design criteria to the most important engineering characteristics required for a successful application of the design. Another aspect is introduced by including an analysis of the heat transfer characteristics of fire-resistant materials to help narrow the criteria and better understand the problem.

Possible Causes in Breaking of Dental Implants Research

2017 ◽  
Vol 907 ◽  
pp. 104-118
Author(s):  
Maria Stoicănescu ◽  
Eliza Buzamet ◽  
Dragos Vladimir Budei ◽  
Valentin Craciun ◽  
Roxana Budei ◽  
...  
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Scientific Literature ◽  
Surface Characteristics ◽  
Raw Material ◽  
New Materials ◽  
Materials Used ◽  
Type Of Failure ◽  
First Time ◽  
Consequent Increase

Dental implants are becoming increasingly used in current dental practice. This increased demand has motivated manufacturers to develop varieties of product through design, but also looking for new materials used to improve surface characteristics in order to obtain a better osseointegration. But the increase in the use of implants goes to a consequent increase in the number of failures. These failures are caused either by treatment complications (peri-implantitis), by fatigue breakage under mechanical over-stress, by defective raw material, or due to errors during the insertion procedures. Although they are rare, these complications are serious in dentistry. Before to market a dental implant to clinical practitioners, the product is validated among other determinations in number of biocompatibility research. Raw material issues, details about its structure and properties are less published by the scientific literature, but all this are subject of a carefully analysis of the producers. Breaking of dental implants during surgical procedures, during the prosthetic procedures or during use (chewing, bruxism, accidents, etc.), is the second most common cause of loss of an implant after consecutive peri-implantitis rejection. Although the frequency of this type of failure for a dental implant is much smaller than those caused by the peri-implantitis, a detailed study of broken implants can explain possible causes. The use of scanning electron microscopy (SEM) in the study of the cleave areas explain the production mechanism of cleavages, starting from micro-fissures in the alloy used for the production of dental implants. These micro-fissures in weak areas of the implant (anti-rotational corners of the polygons, etc.) could generate a serious risk of cleavage first time when a higher force is applied.

NEW MATERIALS USED AS OPTICAL WINDOW IN THIN FILM SOLAR CELLS

2002 ◽  
Vol 09 (05n06) ◽  
pp. 1675-1680 ◽  
Author(s):  
G. GORDILLO
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Thin Film Solar Cells ◽  
Morphological Properties ◽  
New Materials ◽  
Optical Window ◽  
Force Microscopy ◽  
Atomic Force ◽  
Window Systems ◽  
Materials Used

The purpose of this work is to investigate new materials which present good properties to be used as optical window and buffer layer in thin film solar cells based on CdTe and CuInSe 2. As potential candidates for optical windows, two different bilayer systems were studied: ZnO/In x Se y and ZnO/ZnSe. They are planned to be used later in the fabrication of solar cells with structures CuInSe 2/ In x Se y/ ZnO and ZnO/ZnSe/CdTe. The methods used to prepare the different window materials, as well as the technological stages of the solar cell fabrication, will be described. Additionally, the optical and morphological properties of the window systems will be studied through transmittance and atomic force microscopy (AFM) measurements. Preliminary results obtained with Cu(In,Ga)Se 2 solar cells, fabricated using ZnO/In x Se y as optical window, will be reported. They will be compared with those obtained using ZnO/CdS as optical window, which is regularly used in this type of cells.

Active Outer Ring Cooling of High-Loaded and High-Speed Ball Bearings

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Michael Flouros ◽  
Markus Hirschmann ◽  
Francois Cottier ◽  
Peter Gloeckner ◽  
Klaus Dullenkopf
Keyword(s):  
Heat Generation ◽  
High Speed ◽  
High Rate ◽  
Outer Ring ◽  
Excessive Pressure ◽  
Pressure Losses ◽  
Aero Engine ◽  
Design Characteristics ◽  
Materials Used ◽  
Critical Limits

Bearings for aero engine applications are subjected to a high thermal impact because of the elevated speeds and loads. The high rate of heat generation in the bearing cannot be sustained by the materials used and, in the absence of lubrication, will fail within seconds. For this reason, aero engine bearings have to be lubricated and cooled by a continuous oil stream. The heat that is generated in the bearings through friction is transferred into the oil. Oil itself has limited capabilities and can only remove heat as long as its temperature does not reach critical limits. When the critical limits have been reached or even exceeded, the oil will suffer chemical decomposition (coking) with loss of its properties and subsequently cause a detrimental impact on the rotating machinery. Oil is normally transferred into the bearings through holes in the inner ring, thus taking advantage of the centrifugal forces due to the rotation. On its way through the bearing, the oil continuously removes heat from the inner ring, the rolling elements, and the bearing cage until it reaches the outer ring. Since the oil has already been heated up, its capability to remove heat from the outer ring is considerably reduced. The idea to provide the bearing with an “unlimited” quantity of oil to ensure proper cooling cannot be considered, since an increase in the oil quantity leads to higher parasitic losses (churning) in the bearing chamber and increased requirements on the engine's lubrication system in terms of storage, scavenging, cooling, weight, etc., not mentioning the power needed to accomplish all these. In this sense, the authors have developed a method that would enable active cooling of the outer ring. Similar to fins, which are used for cooling electronic devices, a spiral groove engraved in the outer ring material would function as a fin body with oil instead of air as the cooling medium. The number of “threads” and the size of the groove design characteristics were optimized in a way that enhanced heat transfer is achieved without excessive pressure losses. An experimental setup was created for this reason, and a 167.5-mm pitch circle diameter (PCD) ball bearing was investigated. The bearing was tested with and without the outer ring cooling. A reduction of 50% of the lubricant flow through the inner ring associated with a 30% decrease in heat generation was achieved.

scholarly journals Optimization of thermal efficiency of a parabolic trough solar collector (PTSC) based on new materials application for the absorber tube selective coating and glass cover

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Hamzeh Jamali
Keyword(s):  
Thermal Efficiency ◽  
Material Selection ◽  
New Materials ◽  
Selective Coating ◽  
Glass Cover ◽  
Optical And Mechanical Properties ◽  
Materials Used ◽  
Heat Transfers ◽  
Parabolic Trough Solar Collector

This article aims to demonstrate a solution in order for an optimization of PTSCs thermal efficiency. The solution focuses on the radiative heat transfers occurring within the absorber tube of a PTSC unit of a solar power plant situated in Shiraz, Iran as the paper case study. Since the existing heat transfers procedure all comes down to the optical properties of the materials used in the absorber tube of a PTSC unit, an ideal material selection can directly influence the heat transfers and consequently improve the thermal efficiency of a PTSC unit to a great extent. This paper comes up with new materials selection in which graphene nanostructure and BOROFLOAT 33 are respectively used as absorber tube coating and absorber tube glass cover for their exceptional optical and mechanical properties. Meanwhile, a numerical and analytical comparison is made between the thermal efficiencies of a PTSC unit in different states.

scholarly journals Eksistensi Perhimpunan Pemilik dan Penghuni Satuan Rumah Susun (PPPSRS) dalam Kewenangan Pengelolaan Rumah Susun Sewa

Wajah Hukum ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 409
Author(s):  
Nuraini Zachman ◽  
Nur Fauzia
Keyword(s):  
Urban Areas ◽  
Voting Rights ◽  
Scientific Paper ◽  
Management Agency ◽  
Technical Management ◽  
Analysis Technique ◽  
Approach Method ◽  
Materials Used ◽  
Data Collection Technique ◽  
Alternative Choice

Flats are a response to the needs of housing for the community and become an alternative choice for providing ideal housing for developing countries. The purpose of research and writing of this scientific paper through the normative approach method is to analyze the Activities of Management of Flats by the Management Agency, the existence of the Association of Owners and Occupants of Apartment Units (PPPSRS), Voting Rights Related to the Authority of Management and Management of Rental Flats compared to Management of Flats Commercial. In this study using an empirical juridical approach because the researcher was carried out directly on the manager of the rental apartment. The scope of this research is the management of flats and its objects are flats in urban areas. The materials used are field materials and library materials. The data collection technique is document study and the analysis technique is qualitative analysis. The activity of managing the apartment is obliged to be the manager of a legal entity, namely the Association of Owners and Residents of Apartment Units which have been made a legal deed by the Regent or Mayor of the Level II Region and the determination of the voting rights of these members has not been fully realized. Management of simple rental apartments is required by Technical Management Unit (UPT), while Management of Commercial Flats is the Management Body of Commercial Flats, which is the Association of Owners and Occupants of Flat Units, developer as a temporary Management Agency.

scholarly journals Guidance and Practice in Planning Cycling Facilities in Europe—An Overview

2021 ◽  
Vol 13 (17) ◽  
pp. 9560
Author(s):  
Bettina Schröter ◽  
Sebastian Hantschel ◽  
Caroline Koszowski ◽  
Ralph Buehler ◽  
Paul Schepers ◽  
...  
Keyword(s):  
European Countries ◽  
Background Information ◽  
Success Factor ◽  
Buffer Zones ◽  
Systematic Overview ◽  
Street Level ◽  
User Groups ◽  
Design Characteristics ◽  
Mode Of Transport ◽  
Provide Background Information

The provision of convenient, safe and seamless facilities for cyclists is one core success factor in promoting cycling as a mode of transport. Cycling infrastructures and planning philosophies differ greatly between countries, but there is no systematic overview or comparison of similarities and dissimilarities. The aim of this study is to provide an in-depth international overview of guidance material for cycling facilities in European countries and to develop recommendations for advancing provisions for cyclists. International guidance materials for cycling facilities along street sections are collated, systemised and compared. For researchers, the findings provide background information to better understand cycling behaviour and safety. For planners, the findings support their efforts to support cycling and to improve guidance materials. The results show that, in general, countries that are just beginning to promote cycling tend to offer a greater variety of cycling infrastructures in their guidance materials than more mature cycling countries. Countries differ in whether they prefer to put cyclists on the street level or on the sidewalk and whether they mix cyclists with other user groups in the same space. There was even greater variability among countries in the criteria for selecting types of cycling facilities than in the design characteristics (width, buffer zones, etc.).

The Emissivity and Absorptivity of Parachute Fabrics

1959 ◽  
Vol 81 (3) ◽  
pp. 195-200 ◽  
Author(s):  
J. P. Hartnett ◽  
E. R. G. Eckert ◽  
R. Birkebak
Keyword(s):  
Heat Transfer ◽  
High Speed ◽  
Wave Length ◽  
Radiant Energy ◽  
Temperature History ◽  
Appreciable Amount ◽  
Sufficient Information ◽  
Radiation Properties ◽  
History Of ◽  
Materials Used

The use of parachutes for recovery of information and equipment from high-speed vehicles has directed attention to the heating problem which in some instances may be so severe as to cause destruction of the parachute. Consequently, the parachute engineer requires sufficient information on the heat-transfer characteristics of geometries resembling those of parachutes and on the heat-transfer properties of the materials used to allow a calculation of the temperature history of a descending parachute. In particular, the radiation properties of the parachute materials must be known since the parachute is receiving radiant energy from the sun and loses energy by radiation to the surroundings. The measurement of radiation properties for such parachute materials is more complicated than for solid surfaces since an appreciable amount of energy is transmitted by such fabrics. It is the purpose of this paper to describe the equipment which was used to measure the absorptivity for solar radiation and the long-wave-length emissivity for such parachute materials and to report these data for a number of important parachute materials.

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