This study is meant to help develops better facilities for Tungsten Carbide powder production process. The 10 kg-capacity machine used was able to produce 85 -95.49 percent purity Tungsten carbide powder. When measured most of the particle sizes and distribution between 0.03-350.00 !lm. which are considered large sized. More than that those tungsten carbide particles are contaminated by other kinds of metal especially Cobalt binder. We have tried to improve the Tungsten Carbide manufacturing processes by combining more steps including ball milling drying and screening. After 24-hours ball milling process the result showed that we were able to produce smaller Tungsten Carbide paliicles sizing from 0.025 to 30.00 ~lm. The obtained particles are also rounder and with 99.50 percent purity. They are also easier to grade. The Tungsten Carbide manufacturing technology yet needs a further development to eventually produce the desired hard material.

The objectives of this research were to find the distribution of food demand for laying hens and to find the optimum amount of that food production which had minimum cost. The data consisted of customer purchase orders for the food of laying hens price of food for laying hens cost per unit for the food inventory cost related to food of laying hens in which the food was out of stock such as fine overtime urgent purchase for material. They were collected in 2008-2009 form a factory in Nakhonratchasima province. The collected data were analized in order to explore the distribution of the monthly food demand for the laying hens and to see the rate of inventory per unit. The results were used in the stochastic linear programming model for aggregate planning in which the optimum production minimum cost could be obtained. Programming algorithm in MATLAB and tools in Linprog software were used to get the solution. The distribution of the food demand for laying hens and the random numbers were used in the model. The study found that the distribution of food demand for laying hens every month has normal distribution (January to December). The monthly average amount of production from January to December were 10936.94 12913.74 11898.12 13096 15443.26 14916.33 10322.64 10818.21 11393.11 11700.72 9706.05 and 11702.05 respectively. The minimum total cost average for 12months was Baht 62422386.98.

This research is to study the recycle process of hard materials high hardness type and cemented carbide produced by press forming and sintering process included cemented carbide mixed with tungsten carbide cobalt silicon titanium and others. The research aims to recovery tungsten to use it again. It starts in cleaning and ball milling materials for resizing from length 12-25 mm. width 10-15 mm and thickness 2.5-8.0 mm. then disintegrated with the electric-chemical process filtering metal powder cleaning and drying. The result of dissolved materials with electricchemical process in 85% condensed HCl 6-24 volts and 3-10 amperes. The solution heats up 180 degree Celsius is found that material will be 550 11m of W03 the same as usage of Phosphoric Solution. The result of the study in dissolved materials by using the conductor of electricity is found that usage of cobalt is the best to disintegrate tungsten carbide better than tungsten carbide and stainless steel 10-15%. The result of this research is found that the best practice of tungsten carbide recovery is dissolved materials with electric-chemical process in not over 7N condensed HCl 6.00 volts and 3.00 amperes. The metal powder will be almost 100% pure tungsten carbide and particle sized distribution is 34-360 11m. After ball milling for 24 hours particle sized distribution is less than 60 11m compared with the imported metal powder. It is concluded that the recycle of cemented carbide into tungsten carbide powder qualified for sintering work and produced to the durable hard materials. It ensures that this research is useful for the related industry and the approach for production of tungsten carbide which was instead of the imported metal powder.

The objectives of this research are to propose the mode estimation method of Inverse Gaussian data and to compare three mode estimation methods. Those methods are simple method adjusted mode method with term (n+1)/n and adjusted mode method with term (n+2)/n. The performance of each method can be measured by the absolute bias (|Bias|) and the mean square errors (MSE). This study was performed by using different sample sizes (n) of 5 10 20 30 and 50 whereas the parameter  is fixed to be 1 and parameters  are fixed to be 1 3 5 10 15 and 20. This research used the Monte Carlo Simulation technique. The experiment was repeated 50000 times for each condition. The results showed that the adjusted mode method with term (n+2)/n gave the lowest value of |Bias| and MSE in most of the criterions of sample sizes and parameter values.