Numerical Study of Scan Speed Selection and Kerf Depth Prediction in Silicon Laser Machining

In recent times, lasers have gained popularity in machining applications. This trend has been due to the various unique properties that lasers posses. These properties include the ease of manipulation, and the ability to focus the beam to a small spot. Laser machining offers a better alternative to traditional machining since it does cause tool wear, and no mechanical cutting force is required. In this research, effects of the Nd:YAG laser scan speed on kerf depth is investigated. A numerical model was developed using finite element analysis method to investigate the effects using COMSOLR. ImageJR software was used for image analysis and generation of kerf depth predictions. The results of this study show that increasing the laser scan speed led to a decrease in the kerf depth. Various scan speeds can also be optimally selected for different laser application. Cutting quality is improved if scan speeds of the laser are chosen properly. Keywords: Scan speed, kerf depth, laser

Ground Water Pollution and Emerging Environmental Challenges of Industrial Effluent Irrigation: A Case Study of Mettupalayam Taluk, Tamilnadu

Industrial disposal of effluents on land and the subsequent pollution of groundwater and soil of surrounding farmlands – is a relatively new area of research. The environmental and socioeconomic aspects of industrial effluent irrigation have not been studied as extensively as domestic sewage based irrigation practices, at least for a developing country like India. The disposal of effluents on land has become a regular practice for some industries. Industries located in Mettupalayam Taluk, Tamil Nadu, dispose their effluents on land, and the farmers of the adjacent farmlands have complained that their shallow open wells get polluted and also the salt content of the soil has started building up slowly. This study attempts to capture the environmental and socioeconomic impacts of industrial effluent irrigation in different industrial locations at Mettupalayam Taluk, Tamil Nadu, through primary surveys and secondary information. This study found that the continuous disposal of industrial effluents on land, which has limited capacity to assimilate the pollution load, has led to groundwater pollution. The quality of groundwater in shallow open wells surrounding the industrial locations has deteriorated, and the application of polluted groundwater for irrigation has resulted in increased salt content of soils. In some locations drinking water wells (deep bore wells) also have a high concentration of salts. Since the farmers had already shifted their cropping pattern to salt-tolerant crops (like jasmine, curry leaf, tobacco, etc.) and substituted their irrigation source from shallow open wells to deep bore wells and/or river water, the impact of pollution on livelihoods was minimized. Since the local administration is supplying drinking water to households, the impact in the domestic sector has been minimized. It has also been noticed that in some locations industries are supplying drinking water to the affected households. However, if the pollution continues unabated it could pose serious problems in the future

Balancing health and livelihoods: Adjusting wastewater irrigation guidelines for resource-poor countries

Waste waters, Irrigation water, Urbanization, Water pollution, Public health, Farmers, West Africa