第１章 ＧＥＭ調査の概要（分析の枠組み；調査方法；起業活動の定義；起業活動率；起業活動と経済成長；起業の計画と失敗） 第２章 起業家と事業特性（起業家の背景；起業家の能力；事業特性；起業家教育） 第３章 起業の環境（社会的資源；起業家に対する評価；経済危機の影響；起業活動の投資環境） 第４章 専門家調査（資金調達；政府の方針；支援プログラム；教育システム；技術移転；コマーシャル・サービス；起業文化；事業機会；経営能力；起業家に対する評価；女性への支援；急成長への注目；イノベーションへの関心；調査結果） 第５章 政策への提

起業と経済成長 : global entrepreneurship monitor調査報告

This work investigated the influence of graphite on the wear behavior of Al 7075/Al 2 O 3 /5 wt.% graphite hybrid composite. The investigation reveals the effectiveness of incorporation of graphite in the composite for gaining wear reduction. The Al 7075 (aluminium alloy 7075) reinforced with Al 2 O 3 –graphite were investigated. The composites were fabricated using liquid metallurgy route. Ceramic particles along with solid lubricating materials were incorporated into aluminium alloy matrix to accomplish reduction in both wear resistance and coefficient of friction. The Al 7075/Al 2 O 3 /graphite hybrid composite was prepared with 5 wt.% graphite particles addition and 2, 4, 6 and 8 wt.% of Al 2 O 3 . The hardness, tensile strength, flexural strength and compression strength of the Al 7075–Al 2 O 3 –graphite hybrid composites are found to be increased by increased weight percentage of ceramic phase. The wear properties of the hybrid composites containing graphite exhibited the superior wear-resistance properties.

Study on mechanical and wear properties of Al 7075/Al2O3/graphite hybrid composites

In this study, the effect of arc mode in cold metal transfer (CMT) process on the porosity characteristic of additively manufactured Al-6.3%Cu alloy has been systematically investigated. The variants include conventional CMT, CMT pulse (CMT-P), CMT advanced (CMT-ADV) and CMT pulse advanced (CMT-PADV) and experiments were performed on both single layer deposits and multilayer deposits. The mechanism of porosity generation using the CMT arc mode variants is discussed. It was found that deposit porosity is significantly influenced by the arc mode type of CMT process. Conventional CMT is not suitable for the additive manufacturing process because it produces a large amount of gas pores, even in single layer deposit. CMT-PADV proved to be the most suitable process for depositing aluminium alloy due to its excellent performance in controlling porosity. With correct parameter, setting the gas pores can be eliminated. It was found that the key factors that enable the CMT-PADV process to control the porosity efficiently are the low heat input, a fine equiaxed grain structure and effective oxide cleaning of the wire.

Effect of arc mode in cold metal transfer process on porosity of additively manufactured Al-6.3%Cu alloy

Many different polymers and polymer composites are used for engineering applications in which friction and wear are critical issues. This article briefs (a) the importance of polymer tribology in general, (b) the special design principles of polymer composites for low friction and wear under sliding against smooth metallic counterparts, and (c) synergistic effects of nano-particles and traditional fillers and fibers for an optimal tribological performance. Based on these fundamental aspects, the article reviews traditional applications of polymeric tribo-components in mechanical and automotive engineering, including slide elements in textile machines, filament wound bushings for harsh environments, cages of high-precision ball bearings in dental turbines, and hybrid bushings in Diesel fuel injection pumps. A following chapter on special developments of tribo-components outlines (a) ways to achieve electrical conductivity of polymer bearings, (b) the enhancement of self-lubrication and self-healing potential by the incorporation of micro-capsules into the polymer matrix, (c) modern additive manufacturing methods for friction and wear loaded polymer parts, (d) the application and properties of high temperature polymer coatings, and (e) the composition and use of polymer composites under friction at cryogenic temperature conditions.

Polymer composites for tribological applications

The present investigation is aimed at to study the effect of welding processes such as GTAW, GMAW and FSW on mechanical properties of AA6061 aluminium alloy. The preferred welding processes of these alloys are frequently gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) due to their comparatively easier applicability and better economy. In this alloy, the weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often causes inferior weld mechanical properties and poor resistance to hot cracking. Friction stir welding (FSW) is a solid phase welding technique developed primarily for welding metals and alloys that heretofore had been difficult to weld using more traditional fusion techniques. Rolled plates of 6 mm thickness have been used as the base material for preparing single pass butt welded joints. The filler metal used for joining the plates is AA4043 (Al-5Si (wt%)) grade aluminium alloy. In the present work, tensile properties, micro hardness, microstructure and fracture surface morphology of the GMAW, GTAW and FSW joints have been evaluated, and the results are compared. From this investigation, it is found that FSW joints of AA6061 aluminium alloy showed superior mechanical properties compared with GTAW and GMAW joints, and this is mainly due to the formation of very fine, equiaxed microstructure in the weld zone.

Effect of welding processes on tensile properties of AA6061 aluminium alloy joints

TiO2-epoxy nanocomposites were fabricated by using an innovative ultrasonic dual mixing process (UDM) process consists of ultrasonic mixing with simultaneous impeller stirring. TiO2 nanoparticles were used as reinforcement in epoxy resin with weight percentages 5, 10 and 15 respectively. Mechanical properties of each group of composite material were identified using tensile and dynamic mechanical measurements. The effect of TiO2 nanoparticles addition on dynamical mechanical properties of epoxy matrix in the terms of storage modulus and tanδ value with respect to the temperature at a dynamic heating rate of 2 °C/min were studied. The dispersion condition of TiO2 content in epoxy matrix has been thoroughly investigated by using field emission scanning electron microscopy (FESEM) analysis. Tensile tests and thermal gravimetric analysis (TGA) were performed on each group of TiO2-epoxy composite to determine their tensile strength, toughness and thermal stability.

Improving mechanical and thermal properties of TiO2-epoxy nanocomposite

The influence of porosity and particles content on dry sliding wear of cast in situ Al(Ti)-Al2O3(TiO2) composite

To obtain cluster free homogeneous dispersion of carbon nanotubes in polymer matrix, variety of strategies were applied. In the present work, we report a systematic approach to obtain a superior level of dispersion of multi-walled carbon nanotubes (MWCNTs) in epoxy by applying simultaneously ultrasonic waves and shear force generated by axial flow impeller. The influence of dispersion of MWCNTs on anti-corrosion, mechanical and thermal properties of MWCNT/epoxy nanocomposite was investigated. Field Emission Scanning Electron Microscopy (FESEM) studies confirmed cluster free uniform dispersion of MWCNTs in epoxy matrix, which lead to enhanced tensile strength by 35%, toughness by 53% and storage modulus by 35% on loading of 0.75 wt% of MWCNTs in epoxy. It was found that when mild steel was coated with MWCNT/epoxy nanocomposite (0.75 wt%), the corrosion rate decreased upto 2.5 × 10 −3  MPY and protection efficiency increased upto 99.99%.

Thermo-mechanical and anti-corrosive properties of MWCNT/epoxy nanocomposite fabricated by innovative dispersion technique

An innovative ultrasonic dual mixing process (ultrasonic mixing along with impeller stirring) has been employed to disperse round Al 2 O 3 (

P.K. Ghosh

Papers

Improving mechanical and thermal properties of TiO2-epoxy nanocomposite

The influence of porosity and particles content on dry sliding wear of cast in situ Al(Ti)-Al2O3(TiO2) composite

Thermo-mechanical and anti-corrosive properties of MWCNT/epoxy nanocomposite fabricated by innovative dispersion technique

Innovative application of ultrasonic mixing to produce homogeneously mixed nanoparticulate-epoxy composite of improved physical properties

Facile fabrication of epoxy-TiO2 nanocomposites: A critical analysis of TiO2 impact on mechanical properties and toughening mechanisms