Environmental Assessment of the Set-net Operation in Rayong Province, Thailand

Environmental assessment of set-net operation in Mae Rumphueng Beach, Rayong Province was evaluated during 2013-2014. Field surveys around the set-net fishing ground were conducted in the beginning (October 2013), middle (January 2014), ending (April 2014) periods of the operation and six months after the operation ending (October 2014). The results of paired t-test showed that acid volatile sulfide (AVS) of the bottom sediments within set-net A, set-net B and the reference area from four periods were not significantly different (p>0.05). Additionally, average amount of AVS including set-net A, set-net B and the reference area in the beginning (0.0011±0.0018 mg/g dry), middle (0.0026±0.0029 mg/g dry) ending (0.0028±0.0028 mg/g dry) and after-ending (0.0053±0.0117) were much lower than the criteria value for critical farm (2.5 mg/g dry proposed by Yokoyama, 2003). The density of benthic macro-fauna during middle and ending periods in set-net area were significantly higher than those in other areas; whereas those during beginning and after-ending periods were not significantly different. These results indicated that set-net operation did not relevant to the polluted substance, AVS, but had an influence in the increasing of benthic macro-fauna density during the operation season, which was recovered to the initial condition after removal of gear construction

Rancang Bangun Horizontal Gas Cutting Machine untuk Pemotongan Pipa

In the fabrication construction course held at the Fabrication Lab, Mechanical Engineering, Yogyakarta State University, it is necessary to provide workpieces in the form of metal pipe with sizes Ø 4“ to Ø 10". In cutting activity, metal pipe can shift or rotate, so that it is very dangerous for operator who conduct the cutting activity, especially if the pipe cutting activity is conducted using a grinding machine. Due to the condition of a round grinding stone and a cylindrical iron pipe, the case will run the risk of making the grinding machine or iron pipe slip. The use of saw is also less effective and less efficient due to it requires a lot of effort and time [1]. Based on the problems, researchers created the Horizontal Gas Cutting Machine as a tool for cutting iron pipe. The research method in the manufacture of machine used Research and Development (R&D) method. The machine project is conducted in five steps, such as needs analysis step, design, implementation, testing and maintenance. Working drawings on the machine design using Autodesk Inventor application. Production process on the machine includes making frames, casing, pipe support, assembling and painting. The result achieved is the creation of a horizontal gas cutting machine for cutting metal pipes that is able to cut pipes quickly, produces even pipe pieces, has brander features and is easy to operat

Tekno Ekonomi Produksi Perekat Aqueous Polymer Isocyanate Berbasis Lateks Karet Alam (Techno-Economic of Natural Rubber Latex-Based Aqueous Polymer Isocyanate Adhesive)

Natural rubber latex (NRL)-based aqueous polymer isocyanate (API) adhesive can potentially be used for the production of wood panels or composites. Bonding properties of the adhesive could meet the standard of the wood panels produced. In order to complete its assessment as a commercial wood adhesive, it is important to conduct a techno-economic analysis of this adhesive. The design and analyses were based on 100 L production capacity. The techno-economic analysis as a basis value of the investment to be incurred in the API adhesive production considered the capability of design tools during the production process. Based on the analysis, to produce API adhesives by 34.8 tons per year it is required an investment of 509.5 million rupiahs. The production cost of API adhesives for Rp 50.000 kg-1 is Rp 35.798 with assuming a sales profit of 21.30%. The payback period is 1 year with shut down point (SDP) of 14%, and the break-even point (BEP) of 20.51%. The analysis at various production capacities (34.8, 50, 75, and 100 tons year-1) indicated that API adhesive production will be more profitable with greater production capacity because it can shorten the payback period and increase the return on investment