In the present study, effect of ZrC vol.% on mechanical properties of AA6061 metal matrix composites (MMCs) produced via stir casting technique was investigated. The vol.% of ZrC particles was varied as 5,10 and 15. The composites were characterized for its microstructure and mechanical properties and their relationships were obtained. The scanning electron microscope (SEM) images revealed uniform distribution and good bonding between the AA6061 alloy and the ZrC particles. The mechanical properties of the AA6061 alloy was found to significantly improve with the addition of ZrC particles from 5 to 15 vol.%, the hardness increased from 32 to 68 HV, yield strength increased from 50 to 86 MPa and the ultimate tensile strength increased from 118 to 165 MPa. However, the % of elongation of the composite samples decreased with 15 vol.% addition of ZrC particles. Sliding wear behaviour of the composites was investigated using a pin-on-disc wear tester at a load of 9.8 N and addition of ZrC particles was significantly found to reduce the wear rate of AA6061 alloy.
There is growing interest in the role and contribution of e-government to the levels of corruption, economic prosperity and environmental degradation of nation states. In this paper, we use publicly available archival data to explore the relationships among them. Results substantiate a significant relationship between (1) e-government maturity and corruption; and (2) e-government maturity, economic prosperity and environmental degradation through the mediating effects of corruption. The findings suggest that while e-government maturity did not contribute to economic prosperity and environmental degradation, its value could be realized indirectly via its impacts on corruption. Our findings contribute to the theoretical discourse on e-government impact by identifying the role of e-government in a country and provide indications to practice on enhancing its economic prosperity and lowering its environmental degradation by managing the levels of e-government maturity and corruption. 相似文献
Diverse novel nanomaterials are being developed for a wide range of applications nowadays. Atomic force microscopy (AFM) assumes specific importance for the measurement of size and other related properties for such nanomaterials. The different aspects related to AFM modes of operation, nanopositioning, sensing systems as well as calibration for reliable characterization in order to meet the nanometrology requirements are discussed. The future targets in this context, set by nanometrology institutes, are also highlighted. 相似文献
We synthesized potential inhibitors of farnesyl diphosphate synthase (FPPS), undecaprenyl diphosphate synthase (UPPS), or undecaprenyl diphosphate phosphatase (UPPP), and tested them in bacterial cell growth and enzyme inhibition assays. The most active compounds were found to be bisphosphonates with electron‐withdrawing aryl‐alkyl side chains which inhibited the growth of Gram‐negative bacteria (Acinetobacter baumannii, Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa) at ~1–4 μg mL?1 levels. They were found to be potent inhibitors of FPPS; cell growth was partially “rescued” by the addition of farnesol or overexpression of FPPS, and there was synergistic activity with known isoprenoid biosynthesis pathway inhibitors. Lipophilic hydroxyalkyl phosphonic acids inhibited UPPS and UPPP at micromolar levels; they were active (~2–6 μg mL?1) against Gram‐positive but not Gram‐negative organisms, and again exhibited synergistic activity with cell wall biosynthesis inhibitors, but only indifferent effects with other inhibitors. The results are of interest because they describe novel inhibitors of FPPS, UPPS, and UPPP with cell growth inhibitory activities as low as ~1–2 μg mL?1. 相似文献
Significant variations were observed in the concentration of pigments (10·0–17·0%, moisture-free basis) and flavour components during different post-harvest processing conditions of saffron (stigmas ex Crocus sativus L). The crocin pigments concentration was highest (15–17%) in the saffron samples dried between 35°C and 50°C either in a solar dryer or in an oven dryer and this also resulted in considerable reduction of normal drying time. Under these conditions the main flavouring component, safranal, was at its peak value of 60% in the oil in almost all the samples except the vacuum oven dried samples which interestingly contained 4-β-hydroxysafranal in major amounts. Studies indicated that 4-β-hydroxysafranal may be an intermediate in the formation of safranal. It was observed that prolonged storage affected the pigments and flavour concentration to a great extent, but proper packaging and storage with 5% moisture in the saffron reduced the deterioration, thereby increasing the shelflife of the product. 相似文献