Fabrication of Metallic Nanocomponents by Forging of Ni3Al-Nanoparticles.

2012 ◽  
Vol 1412 ◽  
Author(s):  
Landefeld Andreas ◽  
Rösler Joachim
Keyword(s):  
High Performance ◽  
High Strength ◽  
Complex Structures ◽  
Free Standing ◽  
Large Numbers ◽  
Upset Forging ◽  
Nanoscale Fabrication ◽  
The Individual ◽  
Near Future ◽  
Very High

ABSTRACTThe trend to manufacture components reduced in size at the micro- and nano-scale is obvious and is becoming more and more the state of art in designing actuators, sensors and chips. In recent years, nanoscale fabrication has developed considerably, but the fabrication of freestanding nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer to get specific geometries such as discs and more complex components such as gears and wheels in the near future. The almost cubic particles are essentially defect-free, therefore, provide very high strength (σ>2500MPa) in combination with excellent formability (|ϕ|>1,6). There are two approaches for forming these small particles. Upset forging is used to forge small discs (height<100nm) and to shape the nanoparticle in specific areas. Press forging into nano-dies is used to forge more complex structures. In this way free-standing, high-strength, metallic nanoobjects may be shaped into components with dimensions in the 100 nm range. By assembling such nano-components, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).

Roof Structural System Study with Use of UHPC

2017 ◽  
Vol 259 ◽  
pp. 70-74
Author(s):  
Milan Holý
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Construction Materials ◽  
High Strength ◽  
Structural System ◽  
Total Load ◽  
Dominant Component ◽  
Industrial Buildings ◽  
Normal Strength ◽  
Very High

This paper deals with the roof structural system using prestressed girders made of ultra-high performance concrete (UHPC). One of the aims of this study is to verify whether the option of the UHPC girders could be under certain boundary conditions competitive with the commonly used construction materials. Due to its high strength, UHPC enables the design of the structural elements with the high load bearing capacity and with smaller slenderness compared to normal strength concrete elements. The price of UHPC is currently still very high compared to the normal strength concretes or steel. Therefore, its use for the usual designed structures does not recently seem too economically attractive. The effect of material savings is nonnegligible in the case, that a self-weight of the structure forms dominant component of the total load. In addition to the high strength, UHPC has very high resistance to environmental influences. It is therefore likely, that UHPC could be advantageously applied e.g. for the roofing of industrial buildings of chemical plants with high aggressive environments, because there are high demands on the life cycle of the structure.

scholarly journals State of the Art: Mechanical Properties of Ultra-High Performance Concrete

2017 ◽  
Vol 3 (3) ◽  
pp. 190-198 ◽  
Author(s):  
Mohamadtaqi Baqersad ◽  
Ehsan Amir Sayyafi ◽  
Hamid Mortazavi Bak
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
State Of The Art ◽  
High Strength ◽  
Structural Members ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
The Past ◽  
Very High

During the past decades, there has been an extensive attention in using Ultra-High Performance Concrete (UHPC) in the buildings and infrastructures construction. Due to that, defining comprehensive mechanical properties of UHPC required to design structural members is worthwhile. The main difference of UHPC with the conventional concrete is the very high strength of UHPC, resulting designing elements with less weight and smaller sizes.  However, there have been no globally accepted UHPC properties to be implemented in the designing process. Therefore, in the current study, the UHPC mechanical properties such as compressive and tensile strength, modulus of elasticity and development length for designing purposes are provided based on the reviewed literature. According to that, the best-recommended properties of UHPC that can be used in designing of UHPC members are summarized. Finally, different topics for future works and researches on UHPC’s mechanical properties are suggested.

Current Reverse Logistic for End of Life Computer in Malaysia

2013 ◽  
Vol 315 ◽  
pp. 536-539 ◽  
Author(s):  
Siaw Hua Chong ◽  
Sulaiman B. Hasan ◽  
Sia Chee Kiong
Keyword(s):  
Life Cycle ◽  
End Of Life ◽  
Developing Country ◽  
High Performance ◽  
High Technology ◽  
Short Life ◽  
Reverse Logistic ◽  
Near Future ◽  
Very High

High technology and affordable computers are highly demanded currently. Computers are much faster and with very high performance. This however resulted in short life cycle and there is a need for a system to manage used computer that is collected. The volume of end of life computer that will be generated in a developing country has been forecasted to be between 400-700 million units by the year 2016-2018. This paper reviews current the reverse logistic for end of life computer in Malaysia and how it will evolve in the near future.

A Study on the Development of Slip Form System With Lightweight GFRP Panel

2013 ◽  
Author(s):  
Hyejin Yoon ◽  
Won Jong Chin ◽  
Hee Seok Kim ◽  
Young Jin Kim
Keyword(s):  
High Performance ◽  
High Strength ◽  
Suspension Bridges ◽  
Long Span Bridges ◽  
Long Span ◽  
Management Technology ◽  
Early Strength ◽  
Near Future ◽  
Form System ◽  
Design And Construction

Nowadays, many countries are competing in the erection of long-span bridges with main span longer than 2,000 m owing to the tremendous innovations realized in the domain of high performance and high strength materials as well as in the design and construction technologies. The near future will see a boom in the market of suspension bridges with main span longer than 3,000 m. Since three-dimensionally shaped high concrete pylons would be unavoidably required to construct these super long-span bridges, need is to develop advanced slip form systems for their erection. This paper presents the development of a slip form system applying lightweight GFRP panel. Improved slip form management technology is secured by introducing a slip-up technique using GPS-based verticality control and wireless early strength estimation. A mock-up test is conducted by designing and fabricating the slip form system based on the developed techniques.

An Experiment on the Bond-Slip Behaviors of Pre-Tensioned Prestressed UHPC Members

2016 ◽  
Vol 878 ◽  
pp. 161-164
Author(s):  
Jee Sang Kim ◽  
Dong Hun Choi
Keyword(s):  
Prestressed Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Ultra High Performance Concrete ◽  
Conventional Concrete ◽  
Bond Slip ◽  
Optimum Utilization ◽  
Bond Strengths ◽  
Very High

An Ultra High Performance Concrete (UHPC) exhibits very high compressive and tensile strength and excellent durability comparing to those of the conventional concrete. The applications of UHPC to precast and/or prestressed concrete result the optimum utilization of high strength characteristics. This paper experimentally investigates the bond-slip behaviors between prestressing strands and UHPC in pretnesioned members. The diameters of strands, 12.7mm and 15.2mm, the cover depths and tensioning forces are chosen as variables, which are known to affect the bond behaviors. The bond-slip curves for various specimens are obtained and the equations for bond strengths of UHPC are derived based on experiments.

Study on Ceramsite

2011 ◽  
Vol 374-377 ◽  
pp. 1278-1282
Author(s):  
Pei Xi Ding ◽  
Li Ru Yin
Keyword(s):  
Technological Process ◽  
Thermal Insulation ◽  
High Performance ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Developed Countries ◽  
Large Numbers ◽  
Great Performance ◽  
The Developed Countries

Ceramiste, a lightweight aggregate(LWA), has large numbers advantages: high strength, thermal insulation, anti-seismic and so on. The earliest ceramiste development happened in America, and then widely used in the developed countries, all that most used for buildings and bridges. However the ceramsite research was soon after the foundation of the PRC, and quickly developed around the end of the 1970s. Now ceramsite with high strength and high performance has produced all over word. Personally investigating, with the situation of the detailed technological process of clay-ceramisite and pictures, and there are some most important notices among the production. With great performance, ceramiste is widely used in some catagories, such as insulation concrete, great fillers for filtration ponds and planting.

scholarly journals Porous Structure of Ultra-High-Performance Fibre-Reinforced Concretes

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1637
Author(s):  
Manuel Valcuende ◽  
Josep R. Lliso-Ferrando ◽  
Marta Roig-Flores ◽  
José M. Gandía-Romero
Keyword(s):  
Porous Structure ◽  
High Performance ◽  
Oxygen Permeability ◽  
High Strength ◽  
Fibre Volume ◽  
Curing Temperature ◽  
High Concentration ◽  
Curing Conditions ◽  
Very High ◽  
High Performance Fibre

The aim of this experimental work was to study the porous structure of Ultra-High-Performance Fibre-Reinforced Concretes (UH) made with different fibre volume contents (0%, 1%, 2%) under several curing conditions (laboratory environment, 20 °C, 60 °C, 90 °C), comparing the results with those recorded for ordinary, high strength and very high strength concretes. Scanning electron microscopy, mercury intrusion porosimetry, thermogravimetry, water absorption and oxygen permeability tests were carried out. The results showed a low portlandite content in UH (in the order of 75% lower than in concrete C50) and a low degree of hydration, but they rise with curing temperature. These concretes have a very fine porous structure, with a high concentration of pores on the nanoscale level, below 0.05 µm. Their porosity accessible to water is consequently around 7-fold lower than in conventional (C30), 6-fold lower than in high-strength (C50) and 4-fold lower than in very high-strength (C90) concretes. Their oxygen permeability is at least one order of magnitude lower than in C90, two orders of magnitude lower than in C50 and three orders of magnitude lower than in C30. The percentage of added steel fibre does not affect the UH porous structure.

Experimental Study on High-Performance Water-Reducing Agent in C80 Concrete

2012 ◽  
Vol 193-194 ◽  
pp. 435-439
Author(s):  
Mei Yan Hang ◽  
Ying Jing Lan ◽  
Bing Zhang ◽  
Shu Qiang Qu
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
High Strength ◽  
Reducing Agent ◽  
Mineral Admixture ◽  
Test Results ◽  
Large Numbers ◽  
The Cost

By using the High-performance water-reducing agent to do a series of technical demonstration test, and using the local raw materials, mixing with large numbers of mineral admixture, this paper makes up the cost lower C80 high strength and high performance concrete successfully. The test results show that the High-performance water-reducing agent can improve construction of concrete and physical and mechanical performance and durability after hardening

Decomposition of the metastable beta titanium alloy Ti-15-3

1983 ◽  
Vol 41 ◽  
pp. 264-265
Author(s):  
Y. L. Chen ◽  
S. Fujlshiro
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Alpha Phase ◽  
Thick Sheet ◽  
Omega Phase ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Matrix ◽  
Metastable Beta ◽  
Very High

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.

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