Research of Prospective Materials for Military Protective Structures

2015 ◽  
Vol 796 ◽  
pp. 35-42 ◽  
Author(s):  
Stanislav Rolc ◽  
Jan Křesťan ◽  
Daniel Kopkáně ◽  
Jiří Štoller ◽  
Pavel Manas

Different types of composite materials with potential application in ballistic protection of static objects are discussed and compared in present study. The studied solutions include: 1) the concretes with or without reinforcement, 2) the metallic boxes with internal gap filled with different materials and 3) the ceramics-metallic composite armours. Besides the ballistic resistance, the areal weight and the price are taken into account. The weight of solutions is important in case of static objects mainly from logistic point of view. The proposals of ballistic compositions presented in the study can facilitate the choice of solutions according to specific requests.

2021 ◽  
Vol 13 (1) ◽  
pp. 131-140
Author(s):  
George PELIN

This paper presents an experimental study of the influence of nano metric silicon carbide in the composition of phenolic composites on the coefficient of friction. The paper is divided into three distinct parts investigating from a tribological point of view three different types of composite materials based on phenolic resin with three concentrations of nSiC (0.5; 1 and 2% by mass). In the first part, a comparative study of the behavior of phenolic resin was performed, representing the basis for the development of composite materials. In the second part, a study was performed on laminated materials reinforced with two-dimensional fabrics (glass fiber and carbon fiber, respectively). The last part studied two types of ablative phenolic materials based on micronic cork, on one hand, and on carbon felt on the other hand.


1988 ◽  
Author(s):  
James C. Birdsall ◽  
William J. Davies ◽  
Richard Dixon ◽  
Matthew J. Ivary ◽  
Gary A. Wigell

2019 ◽  
Author(s):  
Heba Abdel Wahed Sayed

A collection of 30 clay oil lamps from Gunther Grimm's excavations in 1973 in the Western necropolis of Alexandria has been classified by Safaa Samir Abu Al Yazid from Tanta University and found to represent 12 different types ranging in time from the Hellenistic to the late Roman periods in Egypt's ancient history. The present paper looks at this collection from the point of view of the symbolic significance of the decorative motifs used in their decoration. These motifs— figural, floral and geometric—had obvious symbolic meaning to their users and signified more than a simple belief in certain deities. They also reflected Roman Egyptian culture.


2010 ◽  
Vol 44 (21) ◽  
pp. 2487-2507 ◽  
Author(s):  
G. Vargas ◽  
F. Mujika

The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports have been taken into account. Some considerations regarding stress and displacement fields are presented. The in-plane shear characterization has been performed on a carbon fiber reinforced unidirectional laminate with several fiber orientation angles: 10°, 20°, 30°, and 45°. Test conditions for both off-axis experimental methods, in order to ensure their applicability, are presented. Off-axis flexure test is considered more suitable than off-axis tensile test for the determination of in-plane shear strength.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3788
Author(s):  
Francesco Asdrubali ◽  
Marta Roncone ◽  
Gianluca Grazieschi

The construction sector is one of the most energy-intensive in the industrialized countries. In order to limit climate change emissions throughout the entire life cycle of a building, in addition to reducing energy consumption in the operational phase, attention should also be paid to the embodied energy and CO2 emissions of the building itself. The purpose of this work is to review data on embodied energy and GWP derived from EPDs of different types of windows, to identify the LCA phases, the most impacting materials and processes from an environmental point of view and to perform a critical analysis of the outcomes. The results show a strong dependence on the typology of the frame, with wooden windows having competitive performances: lower average primary energy non-renewable (1123 MJ/FU), higher average primary energy renewable (respectively 817 MJ/FU) and lower global warming potential (54 kgCO2eq/FU). More transparency and standardization in the information conveyed by the program operators is, however, desirable for a better comparability of windows performances. In particular, the inclusion of the operational impact in the EPD is sporadic, but strongly important, since it can be the most impactful phase.


2019 ◽  
Vol 13 (2) ◽  
pp. 342-362
Author(s):  
Xiaodong Yuan ◽  
Xiaotao Li

Purpose The purpose of this paper is to explore how an organization can combine different types of open innovations and what are the key factors that may influence the combination of different open innovations. Design/methodology/approach The basic methodology of this paper is the longitudinal inductive analysis within the conceptual framework of the open innovation proposed by Dahlander and Gann (2010). In this case study of Xiaomi Tech Inc., the open innovation combination is investigated through examining 25 new products created between August 2010 and December 2016 in terms of four general types: acquiring, sourcing, selling and revealing open innovation. Findings In practice, the combination of different types of open innovations can be realized. A firm may combine different open innovations at three levels: a single product level, a related product cluster level and a company level. In addition, different open innovations can be combined in diverse modes. The purpose of combining different types of open innovations is to overcome the disadvantages of each type and to exploit the advantages of all different types. Many factors may affect a firm’s option of how to combine open innovations. At different development stages, a firm may make and implement corresponding strategic direction based on its innovation capacity and internal resource. For a given strategy, the firm needs to create profits and manage intellectual property in the implementation of open innovations. These factors are interacted each other, rather than isolated. Originality/value The findings of this paper are helpful for better understanding how and why an organization can combine different types of open innovations. From a managerial point of view, an organization may combine different types of open innovations to leverage advantages and avoid disadvantages of each certain type of open innovation. An appropriate combination of different open innovations can effectively improve new product development.


2016 ◽  
Vol 5 (3) ◽  
pp. 73 ◽  
Author(s):  
Haidar F. AL-Qrimli ◽  
Karam S. Khalid ◽  
Ahmed M. Abdelrhman ◽  
Roaad K. Mohammed A ◽  
Husam M. Hadi

The purpose of this work is to present a clear fundamental thought for designing and investigating straight bevel gear made of composite material. Composite materials have the advantage of being light, producing low noises, and extra loading capacities. Due to these properties, it is highly preferable over conventional materials. A comparison between different types of material used in a gear structure will be shown. The outcome shows that a new form of cheap material may be useful for designing a new type of lighter and stiffer gear, designed for robotic arm applications or any power transmission application.


Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4005 ◽  
Author(s):  
Angelats Lobo ◽  
Ginestra

The classic cell culture involves the use of support in two dimensions, such as a well plate or a Petri dish, that allows the culture of different types of cells. However, this technique does not mimic the natural microenvironment where the cells are exposed to. To solve that, three-dimensional bioprinting techniques were implemented, which involves the use of biopolymers and/or synthetic materials and cells. Because of a lack of information between data sources, the objective of this review paper is, to sum up, all the available information on the topic of bioprinting and to help researchers with the problematics with 3D bioprinters, such as the 3D-Bioplotter™. The 3D-Bioplotter™ has been used in the pre-clinical field since 2000 and could allow the printing of more than one material at the same time, and therefore to increase the complexity of the 3D structure manufactured. It is also very precise with maximum flexibility and a user-friendly and stable software that allows the optimization of the bioprinting process on the technological point of view. Different applications have resulted from the research on this field, mainly focused on regenerative medicine, but the lack of information and/or the possible misunderstandings between papers makes the reproducibility of the tests difficult. Nowadays, the 3D Bioprinting is evolving into another technology called 4D Bioprinting, which promises to be the next step in the bioprinting field and might promote great applications in the future.


2018 ◽  
Vol 877 ◽  
pp. 294-298 ◽  
Author(s):  
Kundan Patel ◽  
Jay Patel ◽  
Piyush Gohil ◽  
Vijaykumar Chaudhary

Composite materials play a vital role in many industrial applications. Researchers are working on fabrication of new composite materials worldwide to enhance the applicability of these materials. The present study aimed to investigate the effect of Nano clay loading as filler on the mechanical properties of the bamboo fiber yarn reinforced polyester composite. Five different types of composite specimen were prepared with Nano clay loadings of 0 to 4 % weight fraction using hand lay-up technique. It was observed that the composite sheet with 1 wt % nano clay content exhibited the optimized tensile and flexural strength. However the mechanical properties tend to decrease with addition of nano clay content from 2 to 4 wt %. In spite of that the values of mechanical properties with 2 and 3 wt % nano clay content is higher than 0 wt % nano clay content.


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