1. The mathematical model for making decision to sell the rubber latex to reach the highest return in economics Researchers Raviwan Akarapatima Subongkoch Subhadhirasakun Montira Tangsangasaksri Advisor Mr. Sorachai Saelim Mrs. Suphannee Nawasitpaisan
4. Objective This project attempts to develop mathematical model in order to help make decisions among selling rubber latex, raw rubber sheet, and rubber scraps with maximum revenue.
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6. 1. Producing a rubber sheet Prepare formic acid’s concentration Find Dry Rubber Content (DRC) Find Total Solid Content (TSC) Produce a rubber sheet
7. Finding Dry Rubber Content (DRC) Spin the rubber latex in order to remove an ammonia Pipette rubber latex 20 mL, weight Drop Formic acid 90% w/v, wait until it hard Weight and find % DRC Wash out the acid and bake at 60 0 C for 6 hours
8. (Total Solid Content; TSC) Finding Total Solid Content (TSC) Spin the rubber latex in order to remove an ammonia Pipette rubber latex 20 mL, weight Weight and find % DRC Bake at 60 0 C for 6 hours
9. Producing a rubber sheet Mix rubber latex 6 mL and water 4 mL together in the vessel Pipette Formic acid 1.50% 0.78 mL into the vessel wait until it hard for 30 minutes
10. Wash hard rubber, weight, observe and note a result Bake the rubber at 60 ° C Do all experiments again, change formic acid’s concentration 1.50%, 1.75%, 2.00%, 2.25%, 2.50%, 2.75% and 3.00% respectively Producing a rubber sheet
11. 2. Making a questionnaires Part 1 Individual information such as sex, age, etc. Part 2 The level of contentment of selling raw rubber sheet, rubber latex and rubber scraps test Part 2.1 Evaluate from generality Part 2.2 Evaluate from some conditions
15. 3. Analyze data from the questionnaire Analyze frequencies from the questionnaire Create Regression equation
16. Creating Regression Equations Analyze data with Regressing from SPSS program Make and test Hypothesis Find the coefficients of each variable Create Regression Equations
20. Put the coefficients in front of x n Make an equations like = a+a 1 x 1 +a 2 x 2 +a 3 x 3 +…+a n x n Creating Regression Equations
21. 4. Analyze the level of contentment Analyze the mean of each item of the questionnaire Substitute x with mean in the equations Compare the level of contentment in chart form
26. Results 1. Let the producing time be constant.
27. 1. Let the producing time be constant. a is convenience. From the equation b is price. c is payment. d is quality of product. e is asset. f is amount of Para latex.
28. Results 2. Let the price of selling product be constant.
29. 2. Let the price of selling product be constant. a is convenience. From the equation b is time of production. c is payment. d is quality of product. e is asset. f is amount of Para latex.
30. Results 3. Let the convenience of product transportation be constant.
31. 3. Let the convenience of product transportation be constant. a is price. From the equation b is time of production. c is payment. d is quality of product. e is asset. f is amount of Para latex.
32. Results 4. Let the occupational factors are the same.
33. 4. Let the occupational factors are the same. a is convenience. From the equation b is price. c is time of production . e is quality of product. f is asset. g is amount of Para latex. d is payment.
34. Results 5. Let a number of garden are constant.
35. 5. Let a number of garden are constant. a is convenience. From the equation b is price. c is time of production . e is quality of product. f is asset. g is amount of Para latex. d is payment.
36. Results 6.1 Let Para latex in rainy season is constant.
37. 6.1 Let Para latex in rainy season is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.
38. Results 6.2 Let Para latex in winter is constant.
39. 6.2 Let Para latex in winter is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.
40. Results 6.3 Let Para latex in summer is constant.
41. 6.3 Let Para latex in summer is constant. a is price. From the equation b is convenience. c is investment. d is amount of Para latex. e is production. f is that It’s not an optional to sell other products.
51. Suggestion From the column charts of satisfaction, mostly of the gardeners of sample group are satisfy to sell “ rubber sheets ” .
52. Suggestion These sets of equation can be apply in many places that have been planted Para trees ,but the equations may be chanced because their satisfactions are different. (The way to make the equations are follow in above.)
