Investigation of Properties of Coated Hollow Mini-Spheres

2019 ◽  
Vol 799 ◽  
pp. 26-30
Author(s):  
Viktors Mironovs ◽  
Alexey Tatarinov ◽  
Ervins Blumbergs ◽  
Irina Boiko
Keyword(s):  
Electrical Conductivity ◽  
Adsorption Capacity ◽  
Outer Surface ◽  
Outer Layer ◽  
Cellular Structures ◽  
Light Weight ◽  
Structured Materials ◽  
Low Weight ◽  
Lower Porosity ◽  
High Level

Metal hollow mini-spheres (MHMS) present a basis for the creation of new structured materials due to their low weight and energy adsorption capacity. Typically, MHMS are made of steel with a high level porosity in the sphere’s wall 80-110 microns thick. Modification of the outer surface by copper coating of 20-30 microns imposed by vacuum sputtering provides several times higher electrical conductivity, lower porosity of the outer layer and smoother surface, preserving light weight and flotation properties. This modification will provide better possibilities for spheres’ consolidation by means of sintering and electric brazing and creation of new cellular structures.

Influence of the Laminate Configurations of Transparent Armor on its Ballistic Protection

2014 ◽  
Vol 608 ◽  
pp. 253-258 ◽  
Author(s):  
Priawthida Jantharat ◽  
Ryan C. McCuiston ◽  
Chaiwut Gamonpilas ◽  
Sujarinee Kochawattana
Keyword(s):  
Experimental Results ◽  
Front Face ◽  
Light Weight ◽  
Ballistic Performance ◽  
User Requirement ◽  
Element Analysis ◽  
Minimum Requirement ◽  
National Institute Of Justice ◽  
Ballistic Protection ◽  
High Level

The ballistic performance of transparent armors has been continuously developed for an application on security purposes. Generally, ballistic performance of the laminated glass increases with its thickness and weight while the user requirement prefers high level of ballistic protection with thin and light weight body. In this study, fabrication of light weight glass-PVB transparent armors with the level-3 protection according to the National Institute of Justice (NIJ) standard was attempted. The ballistic performances of various configurations of glass-PVB laminates were determined against 7.62 mm ammunitions. Results from fragmentation analysis indicated the influence of glass-sheet-arrangement in the armor structures on the ballistic damages. The minimum requirement on the thickness of front-face layer was also discussed. To verify the experimental results, finite element analysis was performed on all laminated systems. It was found that the results from computational analysis were in reasonable agreement with the experimental results.

Electrical Conductivity Measurements of Al-Doped ZnO Semiconductor in High Temperature

2018 ◽  
Vol 772 ◽  
pp. 105-109
Author(s):  
Syamsul Hadi ◽  
Husein Jaya Andika ◽  
Agus Kurniawan ◽  
Suyitno
Keyword(s):  
Electrical Conductivity ◽  
Temperature Effects ◽  
Sintering Temperature ◽  
High Porosity ◽  
Conductivity Measurements ◽  
Grain Sizes ◽  
Lower Porosity ◽  
Doped Zno ◽  
Zno Semiconductor ◽  
Zno Doping

Electrical conductivity plays an important role in the performance of thermoelectric semiconductor material. This study discusses the electrical conductivity measurements of Zinc Oxide (ZnO) doping Aluminium (Al) pellet as a material of thermoelectric using four-point probe method at high temperatures. Al-doped ZnO (2 wt%) pellet was sintered at the temperature of 1100°C, 1200°C, 1300°C, 1400°C, and 1500°C with the heating rate of 8°C/minute. SEM and XRD tests show that the higher sintering temperature effects to larger grain sizes, better crystallinity, and lower porosity. There is no electrical conductivity in the sintering sample at 1100°C due to the small grain sizes and high porosity. In the sintering sample at 1500°C, the phase of ZnAl2O4erupted. The highest electrical conductivity of 5923.48S/m of Al-doped ZnO pellet was obtained at the sintering temperature of 1400°C with measurement temperature of 500°C.

Textile as Artificial Nature - From Synthetic Sea Grass to Fibrous Implants

2016 ◽  
Vol 100 ◽  
pp. 181-186
Author(s):  
Nils Krister Persson
Keyword(s):  
Technological Development ◽  
Light Weight ◽  
Textile Processing ◽  
Land Capability ◽  
Low Weight ◽  
Low Degree ◽  
Sea Grass ◽  
The World ◽  
Artificial Nature ◽  
Processing Techniques

We develop the hypothesis that textile and nature have much in common and that in a time of biomimetics textile is a unique class of material that provides a bridge between artefacts, by definition synthetic, and biofacts - material entities found in and produced by nature, i.e. non-synthetic. Furthermore we formulate the (seemingly) contradictorily concept of Artificial Nature. Biomimetics sometimes emphasize the inspirational aspects so that science and technology get input from biology for new technological development for new artefacts. Artificial Nature instead emphasizes the other way around; adding sound, ecology based, technology to nature and in nature for enhancing ecosystem functions.Some characteristics of natural biofact materials and structures include pliability, softness, porosity, light weight, recyclability, and periodicity. Textiles are soft, foldable, of low weight, inherent porous, anisotropic as well as periodic, easily compatible with biodegradability and recyclability. Thus there are many similarities. These are discussed together with a number of cases where textiles are mimicking biofacts. We first look at synthetic see grass (Zostera marina) for remediation of one of the most important biotopes in the world where we show that textile processing techniques are able to make production efficient. Then we look at artificial leaves, i.e. photon collecting flexible patches and indicate the textile realization of such. One of the most valuable ecosystem services is the provision of clean water and maintaining a low degree of pollution in water is of outmost importance. Textile based water purification systems has been constructed and merged with fungus (Zygomycetes) we show the potential for enhancing wet land capability.

Deformation and failure mechanisms of nanoscale cellular structures of metallic glasses

RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 100899-100907 ◽  
Author(s):  
J. C. Zhang ◽  
C. Chen ◽  
Q. X. Pei ◽  
Q. Wan ◽  
W. X. Zhang ◽  
...  
Keyword(s):  
Energy Absorption ◽  
Metallic Glasses ◽  
Failure Mechanisms ◽  
Cellular Structures ◽  
Light Weight ◽  
Deformation And Failure ◽  
Functional Applications ◽  
Absorption Performance

Cellular metallic glasses (MGs) can be good candidates for structural and functional applications due to their light weight, enhanced ductility and excellent energy absorption performance.

State of the scientific and technical knowledge about limiting temperatures in the Repository Site Selection process of Germany with simultaneous consideration to Europe and other European repository concepts

2020 ◽  
Author(s):  
Ute Maurer-Rurack ◽  
Axel Liebscher ◽  
Fabien Magri
Keyword(s):  
Outer Surface ◽  
Site Selection ◽  
Selection Process ◽  
Temperature Limit ◽  
Crystalline Rock ◽  
Technical Knowledge ◽  
Federal Republic Of Germany ◽  
Regulatory Frameworks ◽  
High Level ◽  
Limiting Temperatures

<p>The Federal Republic of Germany has decided to dispose its high-level radioactive waste in deep geological formations. Three types of host rock are considered: rock salt, clay rock and crystalline rock. The Site Selection Act (StandAG<sup>1</sup>), which came into effect on the 16<sup>th</sup> of May 2017, defines the successive steps of the repository siting process, which has to ensure the best possible safety conditions for a period of one million years. Based on precaution considerations, the StandAG (§27 (4) StandAG) sets a preliminary temperature limit of 100°C at the outer surface of a repository container for the preliminary safety assessment.</p><p>This contribution provides an overview about the state of the scientific and technical knowledge on the limiting temperatures in the repository site selection process of Germany. It also illustrates the different treatments of the definition of temperature limits within other European siting processes. The findings highlight that, in Europe, the proposed criteria which consider temperature at the outer surface of a repository container get more and more into focus of research and discussion especially for the three different types of host rocks.</p><p>After presenting the national regulatory frameworks, this contribution summarizes how the European countries address the different temperature related issues for their site selection, their repository concepts and how in turn these all can influence the German safety case strategy for the German site selection. Not at least, links to site selection criteria in other countries (e.g. USA, Japan, Russia) are provided.</p><p><strong>Reference</strong></p><p><sup>1</sup>  StandAG: Standortauswahlgesetz vom 5. Mai 2017 (BGBl. I S. 1074), das zuletzt durch Artikel 2 Absatz 16 des Gesetzes vom 20. Juli 2017 (BGBl. I S. 2808) geändert worden ist.</p>

Which Processes could define Temperature Limits on the Outer Surface of a Container in a Disposal Facility ?

2020 ◽  
Author(s):  
Guido Bracke ◽  
Eva Hartwig-Thurat ◽  
Jürgen Larue ◽  
Artur Meleshyn ◽  
Torben Weyand ◽  
...  
Keyword(s):  
Outer Surface ◽  
Site Selection ◽  
Selection Process ◽  
Temperature Limit ◽  
Crystalline Rock ◽  
Safety Concept ◽  
Disposal Facility ◽  
High Level ◽  
A Site ◽  
Host Rocks

<p>When the recommencement of the search for and selection of a site for a disposal facility for HLRW in Germany was stipulated by the Site Selection Act (StandAG 2017) in 2017, a <strong>precautionary </strong>temperature limit of 100 °C on the outer surface of the containers with high-level radioactive waste in the disposal facility section was set. This <strong>precautionary </strong>temperature limit shall be applied in preliminary safety analyses provided that the “maximum physically possible temperatures” in the respective host rocks have not yet been determined due to pending research. Therefore, this issue is addressed and discussed in this paper, contributing to “pending research” by a review of the literature.</p><p>This presentation briefly discusses a few examples of thermohydraulical, mechanical, chemical and biological processes in a disposal facility, because temperature limits are derived based on safety impacts regarding THMCB-processes. The temperature-dependent processes have been extracted from databases for features, events and processes (FEP-databases). Furthermore, it is dicussed if the feasibility to retrieve and recover HLRW is hampered at high temperatures.</p><p>It is concluded that a design temperature concerning single components of a disposal facility for the preservation of their features can be derived when a safety concept is established. However, the interactions of all relevant processes in a disposal concept must be considered to determine a specific temperature limit for the outer surface of the containers. Therefore, applicable temperature limits may vary for particular safety and disposal concepts in the following host rocks: rock salt, clay stone and crystalline rock.</p><p>Technical solutions for retrieval and design options for recovery seem to be viable up to temperatures of 200 °C with different, sometimes severe, downsides according to expert judgement.</p><p>It is summarized that emperature limits regarding the outer surface of the containers can be derived specifically for each safety concept and design of the disposal facility in a host rock. General temperature limits without reference to specific safety concepts or the particular design of the disposal facility may narrow down the possibilities for optimisation of the disposal facility and could adversely affect the site selection process in finding the best suitable site.</p>

Bamboo-Shaped Carbon Nanotubes on Coal Fly Ash Cenospheres for Pb(II) Adsorption

2020 ◽  
Vol 20 (8) ◽  
pp. 5089-5095
Author(s):  
Xiaomin Zhang ◽  
Jin Li ◽  
Bo He ◽  
Heng Li ◽  
Chao Qi ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fly Ash ◽  
Adsorption Capacity ◽  
Active Sites ◽  
Coal Fly Ash ◽  
Chemical Vapor ◽  
Structural Defects ◽  
3D Network ◽  
Supporting Material ◽  
High Level

The structural defects of bamboo-shaped carbon nanotubes (B-CNTs) provide abundant active sites for ion adsorption during wastewater treatment. However, a suitable supporting material for the growth of B-CNTs growth is less reported. In this paper, the catalytic growth of B-CNTs on the cenospheres (CSs) of coal fly ash was studied. The results showed that all CSs were covered by a layer of B-CNTs during the chemical vapor deposition (CVD) process, regardless of the fluctuation of the iron distribution from 0.52 to 2.09 wt%. B-CNTs with a diameter of 30–40 nm shared a similar morphology of compartment structures, which were uniformly scattered on the surfaces of the CSs and formed a 3D network structure. A high level of structural defects was present on the B-CNTs, which was denoted by an ID/IG value of 1.77 via Raman spectrum analysis. Adsorption experiments of the as-prepared CSs@B-CNTs revealed an excellent adsorption capacity for lead ions of 37.32 mg/g (pH 7, initial concentration of 70 mg/L). By excluding the function of CSs, the adsorption capacity of the pure B-CNTs was estimated to be as high as 275.19 mg/g, which has not been previously reported.

The Lipid Layer: The Outer Surface of the Ocular Surface Tear Film

2001 ◽  
Vol 21 (4) ◽  
pp. 407-418 ◽  
Author(s):  
James P. McCulley ◽  
Ward E. Shine
Keyword(s):  
Water Vapor ◽  
Fatty Acid ◽  
Outer Surface ◽  
Outer Layer ◽  
Tear Film ◽  
Polar Phase ◽  
Lipid Layer ◽  
Water Vapor Transmission ◽  
Aqueous Layer ◽  
Alcohol Composition

The outer layer of the tear film—the lipid layer—has numerous functions. It is a composite monolayer composed of a polar phase with surfactant properties and a nonpolar phase. In order to achieve an effective lipid layer, the nonpolar phase, which retards water vapor transmission, is dependent on a properly structured polar phase. Additionally, this composite lipid layer must maintain its integrity during a blink. The phases of the lipid layer depend on both lipid type as well as fatty acid and alcohol composition for functionality. Surprisingly, the importance of the composition of the aqueous layer of the tear film in proper structuring of the lipid layer has not been recognized. Finally, lipid layer abnormalities and their relationship to ocular disease are beginning to be clarified.

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