Transnational Governance as Contested Institution-Building: China, Merchants, and Contract Rules in the Cotton Trade

We are in an era of uncertainty over whose rules will govern global economic integration. With the growing market share of Chinese firms and the power of the Chinese state it is unclear if Western firms will continue to dominate transnational governance. Exploring these dynamics through a study of contract rules in the global cotton trade, this article conceptualizes commodity chain governance as a contested process of institution-building. To this end, the global commodity chain/global value chain (GCC/GVC) framework must be revised to better account for the broader institutional context of commodity chain governance, institutional variation across space, and strategic action in the construction of legitimate governance arrangements. I provide a more dynamic model of GCC governance that stresses how strategic action, existing institutions, and dominant discourses intersect as firms and states compete for institutional power within a commodity chain. This advances our understandings of how commodity chain governance emerges and changes over time

Reinforcements, production techniques and property analysis of AA7075 matrix composites − a critical review

Aluminium alloy based metal matrix composites are being extensively used in the aerospace, automobile, defense, marine and electronic industries owing to their excellent strength, high resistance to wear, corrosion and better thermal stability. Many investigators have explored different aluminium alloy series composites, like heat treatable AA2024, AA6061 and AA7075 since the properties of these matrix alloys can be easily tailor made to suite specific application due to easy processability and heat treatability. AA7075 alloy matrix is predominantly being used, as it exhibits high ultimate tensile strength, resistance to corrosion and fatigue in the group. In the current review work, attention is focused to present types of reinforcing materials used, benefits of reinforcement hybridization, methods employed for composite production and critical property analysis, with conclusions of experimentation and the suggested prospective applications of AA7075 composites. Due to good castability and moldability variety of processing techniques in solid, semisolid and liquid states are possible. As matrix alloy, low processing temperature, ability to accommodate reinforcements and adoptability to different reinforcing techniques, it is easy to obtain optimal properties as per the application. AA7075 with small addition of copper is paved the path in the field of electronic and military applications due to high thermal and electrical conductance. Even pure metal addition & magnesium with copper facilitate good weldability, plasticity and corrosion resistance. Due to the flexibility in accommodating carbide and oxide compound reinforcements in the matrix, this matrix composite widens versatility limit due to excellent hardness and wear resistance. CNT and graphite reinforcements to this aluminium series matrix are marked as ultra-high precision components in defense field

Spider web approach hardness validation of peak aged Al6061/SiC/h-BN composite and related mechanical characterization

Current work focusses on stir cast Al6061 based composites with SiC (3, 6, 9 wt.%) and h-BN (1, 2, 3 wt.%) as reinforcements and subjected to heat treatments followed by mechanical characterization. Quality level of composites is confirmed from reinforcement distribution and hardness uniformity in castings after homogenization. The castings were further subjected to peak aging and hardness data is refined for accuracy using Spider web approach. Due to lack in the reinforcement spreadout, especially higher volume quantity of h-BN, the peak hardness of Al6061/9 wt.% SiC/3 wt.% h-BN as estimated by Spider web approach is less than the recorded value. The Minitab result is in line with that of experimentally supported Spider web approach. Due to the result of nonuniform dispersivity, beyond the optimum quantity of reinforcement content, fracture surface resulted coarse mirror facets with lower tensile and wear properties. 2 wt.% h-BN quantity with 6 wt.% SiC in the composite is regarded as the optimum quantity of reinforcement, resulted excellent tensile strength with least ductility among the family and is at par with hardness variation trend. It is found that optimum quantity of solid lubricant h-BN in the composite resulted excellent wear resistance even at higher normal loads