ENGINEERING DESIGN HANDBOOK. MILITARY PYROTECHNICS SERIES. PART THREE. PROPERTIES OF MATERIALS USED IN PYROTECHNIC COMPOSITIONS

1963 ◽  
Author(s):  
ARMY MATERIEL COMMAND ALEXANDRIA VA
Keyword(s):  
Engineering Design ◽  
Pyrotechnic Compositions ◽  
Properties Of Materials ◽  
Materials Used

scholarly journals The Mechanical and Material Designs of Composite Ju|’hoansi Arrowheads

2020 ◽  
Vol 4 (3) ◽  
pp. 139
Author(s):  
Courtney Archer ◽  
Iain Campbell ◽  
Fraser Cheyne ◽  
Amos Lim Jun Meng ◽  
Csongor Senanszky ◽  
...  
Keyword(s):  
Physical Properties ◽  
Engineering Design ◽  
Mechanical And Physical Properties ◽  
Properties Of Materials ◽  
Design Skills ◽  
Composite Engineering ◽  
Materials Used ◽  
Composite Designs

In this paper, we elucidate the composite engineering design skills of the Kalahari Ju|’hoansi (San) people, developed over at least tens of thousands of years. In particular, we show that the mechanical and physical properties of materials used by the Ju|’hoansi in the design of arrowheads are intimately linked to their unique geometrical and composite designs. The Ju|’hoansi arrowheads have evolved to become complex engineered units with distinct function-specific purpose. We demonstrate herein that the geometrical designs of the arrowheads are optimised with respect to the material used. We furthermore verify the veracity of the Ju|’hoansi claim that their composite link-shafts are designed to break off leaving the arrowhead in the animal and the remaining parts of the arrow intact, reusable and easily retrievable.

scholarly journals Properties of Materials Used in Roller Compacted Concrete Mixtures

2020 ◽  
pp. 61-72
Author(s):  
Ali Mardani ◽  
Sultan Husein Bayqra ◽  
Süleyman Özen ◽  
Zia Ahmad Faqiri ◽  
Kambiz Ramyar
Keyword(s):  
Roller Compacted Concrete ◽  
Concrete Mixtures ◽  
Properties Of Materials ◽  
Materials Used

scholarly journals Analysis of methods for measuring the dielectric properties of materials in the microwave range of wavelengths.

2021 ◽  
Author(s):  
D.G. Fomin ◽  
◽  
N.V. Dudarev ◽  
S.N. Darovskikh ◽  
◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Communication Systems ◽  
Electronic Devices ◽  
Microwave Range ◽  
Advantages And Disadvantages ◽  
Microwave Electronic ◽  
Functional Features ◽  
Properties Of Materials ◽  
Materials Used ◽  
Resonant Method

One of the modern trends in the development of communication systems, information and telecommunication systems, air traffic control systems, etc. is the transition and development of higher-frequency wavelength ranges. In this regard more and more stringent requirements (in terms of spectrum, out-of-band and spurious radio emission, and in the shape of the output signal) are imposed on radio engineering devices that transmit and receive microwave radio signals. As a result, the requirements for the design and functional features of microwave electronic devices are increasing. One of these requirements is to assess the degree of compliance with the required values of dielectric properties of materials used in the design of microwave electronic devices. This requirement is justified by the fact that the electrical parameters of such microwave devices as: strip filters, power dividers, printed antennas and others, directly depend on the dielectric properties of the materials used in their substrate designs. In this regard, three main methods have now emerged for assessing the dielectric properties of materials: the resonant method, the non-resonant method, and the free space method. Aim. The aim of this article is to carry out a comparative analysis of the known methods for measuring the dielectric properties of materials in the microwave range of wavelengths and devices for their implementation. Materials and methods. The authors of the article reviewed the scientific literature of domestic and foreign publications. Results. For each of the methods for measuring the dielectric properties of materials, their main idea, practical implementation, a mathematical model for processing experimental data and areas of application are given. The advantages and disadvantages for each of the methods for measuring the dielectric properties of materials are given too. Conclusion. The applicability of each of the considered methods depends on such factors as: the shape of the investigated dielectric material, its state of aggregation, the possibility of measuring amplitude or complex transmission and reflection coefficients, the presence of an anechoic chamber, etc.

Materials for Safety and Security

2020 ◽  
pp. 288-320
Author(s):  
Jozef Martinka ◽  
Janka Dibdiakova
Keyword(s):  
Hydrogen Cyanide ◽  
Ignition Temperature ◽  
Fire Risk ◽  
Combustion Products ◽  
Security Engineering ◽  
Insulating Materials ◽  
Properties Of Materials ◽  
Materials Used ◽  
Carbon Monoxide Yield ◽  
The Impact

This chapter deals with materials used in safety and security engineering. The most commonly used materials in this field include shielding materials, materials for protective suits, electrically insulating materials and materials for fire protection. The first part of the chapter describes the properties of materials used in the above applications. The second part of the chapter focuses on characteristics of materials that accurately describe their fire risk. The fire risk of a material is quantified by its resistance to ignition (determined generally by critical heat flux and ignition temperature) and by the impact of the fire on the environment. The impact of fire is usually determined by the heat release rate, toxicity of combustion products (primarily determined by carbon monoxide yield and for materials that contain nitrogen, also through the hydrogen cyanide yield) and the decrease of visibility in the area (depending on the geometry of the area and the smoke production rate).

scholarly journals Esterases affect the physical properties of materials used to seal the endodontic space

2019 ◽  
Vol 35 (8) ◽  
pp. 1065-1072
Author(s):  
M.Q. Marashdeh ◽  
S. Friedman ◽  
C. Lévesque ◽  
Y. Finer
Keyword(s):  
Physical Properties ◽  
Properties Of Materials ◽  
Materials Used
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