A field experiment was planned and executed in randomized block design at Umiam during kharif 2019 to determine the grain yield and economics of upland directseeded rice (Oryza sativa L.) in North-Eastern Hill region under varying phosphorus management practices. The soil of the experimental plot was sandy-clay loam in texture with pH 4.2, high in organic carbon (1.62%) and available K (354 kg/ha), medium in available N (256 kg/ha) and low in available P (6.3 kg/ha). The plot managed with organic nutrient sources i.e. 25% FYM + 25% vermicompost + 25% poultry manure + PSB produced significantly higher number of yield attributes subsequently resulting in higher grain yields. This was followed by 100% RDP fertilized plot and 75% RDP+ PSB + AMF. In terms of economics, 100% RDP plot proved to be the most cost-effective owing to the less cost of fertilizers as compared to organic nutrient sources.
Aluminium alloys are known for their very good strength to weight ratio. Aluminium alloy finds its applications depending upon the alloying agent/agents added. Among other alloying materials Copper, Silicon, Magnesium are some of the alloying agents which are largely used with Aluminium, as they improve the strength of the alloy without affecting the density when compared to pure Aluminium. Addition of Silicon to pure Aluminium improves the strength of the resulting alloy at room temperature. But at higher temperatures (above 150°C) strength of Aluminium-Silicon (Al-Si) alloy is very poor. It is a preferred alloying agent when it comes to casting as the Al-Si alloy shows good casting ability compared to other (alloy without having silicon). But in the present study Copper is used with Aluminium as the major alloying material and silicon is either absent or present only as impurity.Copper addition to the Aluminium improves the alloy strength at room as well as at high temperatures, but at the cost of quality of the cast component. To get good quality, defect-free castings and to improve yield 'casting simulation software' can be used which can predict the casting defects virtually. So in the present study effect of adding Copper in the absence of silicon is studied where casting simulation software helped to predict the solidification time and quality of final cast component. Prediction of solidification time for different compositions of alloy gives an idea about the hardness of the alloy. Simulation results from two types of sand castings (spiral shape, step) are compared for their solidification time. The variation in solidification time with variation of copper weight percentage which is 4, 8, 12% for this experiment is studied. It was found that for a fixed composition the solidification results from both types of sand casting (spiral shape and five-step component) are of similar nature. The shop floor casting of the five step component is done and Rockwall hardness for all three compositions tested. Prediction of solidification time and shrinkage defects results obtained through virtual casting process helps in improving
Aluminium-copper alloys are known for their very good strength at high temperature .Addition of copper improves the strength at high temperatures due to precipitation strengthening. Fluidity in casting is the major factor which affects the cast quality of the final components. Addition of Silicon with copper in Aluminium improves fluidity and finally quality of the cast components. But presence of Silicon adversely affects the strength at high temperature. In the present work cooling curve analysis of Al-Cu alloy (without Silicon) is done for different wt% of copper addition. The current study for Al-Cu alloy is based on sand casting method as it is one of the cost effective manufacturing method. Cooling curve obtained from the simulation results used to predict the fluidity, microstructure of the alloy when copper wt% is varied. Predicted microstructure and grain structure from the cooling curve goes well with the microstructure studied from shop floor casting .In the present work “Z-cast” casting simulation software is used for casting simulation. Among three different alloy composition studied aluminium with 8% copper gives the best results when compared on the basis of grain size .But fluidity analysis reveal poor fluidity for the alloy having 8 wt% of copper. The current analysis helps to study the optimum aluminium –copper alloy composition that can be used in high temperature applications.
Aluminium (Al) alloys are now-a-days used starting from aerospace, automotive body panel, to kitchen ware especially due to their high strength to weight ratio. Aluminium having copper as major alloying element exhibit good mechanical properties at room as well as at high temperature working conditions. But presence of silicon in these alloys adversely affect the strength at high temperature. The current paper analyses change in microstructure and it’s effect on mechanical properties of Aluminium-Copper(Al-Cu) alloy with varying wt% of copper. The Al-Cu alloy developed for study contain silicon as trace element only. Tests carried out to evaluate the impact of such variations on tensile and metallurgical behaviour at room temperature. Analysis of microstructure change with varying wt% of Copper is studied which goes well with the tensile data recorded. Effect of heat treatment (T6) on tensile properties was studied. The tensile results both as cast and heat treated suggest Al-Cu alloy containing 8wt% of Copper as the optimum composition.
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