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"ABSTRAKThe sessile drop method was implemented to calculate the values of the surface tension coefficient of liquid metals. Appropriate software was developed to increase the data processing efficiency and the accuracy of the obtained results. This paper provides information on the structure and applications of the designed programs as well as the underlying mathematical models used during computations. Since the determination of the surface tension coefficient in this study is based on the recognition of drop outlines from a digital image, the problems of calibration and appropriate photography mode adjustments are mentioned in this paper. In addition,the methods of controlling there search equipment using Arduino shields are described. Finally, the research results are presented in the form of graphs which show the temperature dependence of the studied parameters of metallic samples and compared with the literature data. "

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ABSTRACTIn order to respond the global issues regarding climate change and global warming in this new era of globalization, governments and environmentalists set the targets to provide an alternative, sustainable and renewable energy to decrease the pollution emerging from non‐sustainable sources such as a fossil fuels or petrodiesel. The increase in the use of biodiesel fuels is expected to be a better solution to help address the environmental problems impacting on society.Biodiesels are an alternative, environmentally friendly energy resources generated from the transesterification process of animal fats, vegetable oils and other organic resources. The transesterification process of biodiesels can be carried on by using an alkaline as the catalyst to separates the triacylglycerol into an alkyl ester and a glycerol compound. Through this separation, a friendly chemical component similar with a fossil fuel can be produced. Nevertheless, further characteristics of biodiesels need to be observed in order to maximize the performance of biodiesels on the diesel engine.This report will focus on surface tension and density experimental investigations of four biodiesel fuels and nine fractionated methyl ester based on temperature dependency. The results are evidence of the relationship between surface tension and density. Also, the temperature change data characterizes the impact of fatty acid chain length upon density and surface tension."

"The measurement of specific surface area of porous materials has long been important in physical sciences and is currently growing in importance in applied and environmental science. Numerous systems have been developed for surface area measurement by gas adsorption. Commercial systems are available which can measure a wide range of absolute surface area with relative ease. However, their cost is often prohibitive. In this study, an inexpensive apparatus for surface area measurement has been set up to be used for measuring supercritical adsorption of CO2. The Ono-KondoLattice model was used to represent the adsorption isotherm and to determine the surface area. The results of surface area determination using CO2 adsorption combined with OK model have been compared to the numbers obtained from nitrogen BET method. For surface area determination of zeolites and activated carbons, the new methodgive reasonable agreement results (within 10% deviation) compared to the results obtained from nitrogen BET method. In addition, thenew method also gives more reasonable results for surface area determination of coals. As known, the nitrogen BET method gives almost zero of coals? surface area. This might due to the characteristic of the coals? structure that might be change (the pores are closed) during the cooling process in nitrogen BET method. Moreover, the new method can also be used to determine the surface area of porous materials using CO2 adsorption data at various temperatures without sacrificing their accuracy."

"Dalam rangka merespon berbagai isu global yang berkaitan dengan perubahan iklim dan pemanasan global di era globalisasi ini, pemerintah dan para pakar lingkungan menetapkan target untuk menggunakan energi alternatif, terbaharui, dan berkelanjutan untuk mengurangi polusi yang muncul dari sumber energi yang tidak ramah lingkungan seperti bahan bakar fosil atau petrodiesel. Biodiesel merupakan bahan bakar yang dapat diperbaharui serta lebih ramah lingkungan yang diharapkan dapat menjadi solusi yang baik untuk membantu mengatasi masalah lingkungan ini.Biodiesel merupakan sumber energi alternatif yang ramah lingkungan yang dihasilkan dari proses transesterifikasi lemak hewani, minyak nabati dan sumber organik lainnya. Proses transesterifikasi biodiesel dapat dilakukan dengan menggunakan alkali sebagai katalis untuk memisahkan triasilgliserol menjadi suatu ester alkil dan senyawa gliserol. Melalui pemisahan ini, komponen kimia yang mirip dengan bahan bakar fosil dapat diproduksi. Namun demikian, karakteristik biodiesel perlu diperhatikan lebih lanjut untuk memaksimalkan kinerja biodiesel pada mesin diesel.Skripsi ini berfokuskan kepada eksperimen dan penyelidikan terhadap tegangan permukaan dan massa jenis dari empat bahan bakar biodiesel alami dan sembilan metil ester fraksinasi berdasarkan ketergantungan temperatur. Hasil eksperimen ini memberikan bukti adanya hubungan antara tegangan permukaan dan massa jenis. Disamping itu, terlihat juga data perubahan suhu yang mencirikan dampak dari panjang – pendeknya rantai asam lemak pada kepadatan dan tegangan permukaan.

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In order to respond the global issues regarding climate change and global warming in this new era of globalization, governments and environmentalists set the targets to provide an alternative, sustainable and renewable energy to decrease the pollution emerging from non-sustainable sources such as a fossil fuels or petrodiesel. The increase in the use of biodiesel fuels is expected to be a better solution to help address the environmental problems impacting on society.

Biodiesels are an alternative, environmentally friendly energy resources generated from the transesterification process of animal fats, vegetable oils and other organic resources. The transesterification process of biodiesels can be carried on by using an alkaline as the catalyst to separates the triacylglycerol into an alkyl ester and a glycerol compound. Through this separation, a friendly chemical component similar with a fossil fuel can be produced. Nevertheless, further characteristics of biodiesels need to be observed in order to maximize the performance of biodiesels on the diesel engine.

This report will focus on surface tension and density experimental investigations of four biodiesel fuels and nine fractionated methyl ester based on temperature dependency. The results are evidence of the relationship between surface tension and density. Also, the temperature change data characterizes the impact of fatty acid chain length upon density and surface tension."

"Plastic limit is an important property of fine-grained soils. The standard thread-rolling method for determining the plastic limit has long been criticized for requiring considerable judgments from the operator. This study was conducted to seek for a new method on the determination of the plastic limit in a way to overcome the inconsistence result produce by using the standard thread-rolling method. Four different methods were tested. The first method was the modified fall cone method, a method commonly used to obtain a liquid limit. The second method was the rolling device method which is previously proposed by Bobrowski and Griekspoor (1992). The third method was proposed by Wood and Wroth (1978) using a heavier cone. The fourth method was the one proposed by Tao-Wei Feng (2004) which made use of a small soil container. Eight soil samples representing plasticity index (PI) ranging from 15 to 42% were tested. The results indicated that the correlation factor between the standard methods and the suggested methods were in the range 0.72 and 0.99. Regarding to the regression analysis result, the first method is more comparable to the standard thread method"

"Metode Spektrofotometri Sederhana dan Aman untuk Penentuan Iodida. Penentuan iodida menggunakan metode spektrofotometri sederhana dengan bahan kimia tidak berbahaya telah berhasil dikembangkan berdasarkan pembentukan kompleks biru iodium-amilum. Iodida terlebih dahulu dioksidasi menjadi iodium yang dengan penambahan amilum menghasilkan kompleks biru iodium-amilum yang dapat dideteksi menggunakan spektrofotometer pada panjang gelombang 615 nm. Parameter kimia, seperti jenis, waktu reaksi, dan konsentrasi oksidator, serta pH larutan dioptimasi untuk meningkatkan sensitifitas dan efektifitas waktu analisis. Hasil optimasi metode menunjukkan bahwa hasil optimum diperoleh pada mol rasio oksidator iodat terhadap iodida 1:3, waktu reaksi 5 menit, dan pH larutan 1. Pada kondisi optimum tersebut, metode ini memberikan linieritas pengukuran iodida dari 5-40 mg/L dengan koefisien korelasi (R2) 0,9889. Metode ini menawarkan cara yang sederhana, aman, akurat, dan relatif cepat untuk penentuan iodida yang prospektif untuk monitoring sampel iodida.

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In order to practice green chemistry, a simple and safe spectrophotometric method for iodide determination has been successfully developed based on the formation of a blue starch-iodine complex. Iodide was oxidized to form iodine prior to the addition of a starch solution, and the blue starch-iodine complex was directly detected spectrophoto-metrically at a wavelength of 615 nm. The chemical parameters, such as type, reaction time, as well as concentration of oxidizing agents and solution pH were optimized with respect to sensitivity and analysis time. The method showed optimum results under iodate oxidant with a mol ratio of IO3-:I- =1:3, reaction time of 5 minutes, and solution pH of 5. Under these optimum conditions, the method showed linierity measurements from 5-40 mg/L iodide with a correlation (R2) of 0.9889. This technique offers a simple, safe, accurate, and relatively fast method for iodide determination, which is prospective for monitoring iodide samples."

"In order to practice green chemistry, a simple and safe spectrophotometric method for iodide determination has been successfully developed based on the formation of a blue starch-iodine complex. Iodide was oxidized to form iodine prior to the addition of a starch solution, and the blue starch-iodine complex was directly detected spectrophoto-metrically at a wavelength of 615 nm. The chemical parameters, such as type, reaction time, as well as concentration of oxidizing agents and solution pH were optimized with respect to sensitivity and analysis time. The method showed optimum results under iodate oxidant with a mol ratio of IO3 -:I- =1:3, reaction time of 5 minutes, and solution pH of 5. Under these optimum conditions, the method showed linierity measurements from 5-40 mg/L iodide with a correlation (R2) of 0.9889. This technique offers a simple, safe, accurate, and relatively fast method for iodide determination, which is prospective for monitoring iodide samples.

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Metode Spektrofotometri Sederhana dan Aman untuk Penentuan Iodida. Penentuan iodida menggunakan metode spektrofotometri sederhana dengan bahan kimia tidak berbahaya telah berhasil dikembangkan berdasarkan pembentukan kompleks biru iodium-amilum. Iodida terlebih dahulu dioksidasi menjadi iodium yang dengan penambahan amilum menghasilkan kompleks biru iodium-amilum yang dapat dideteksi menggunakan spektrofotometer pada panjang gelombang 615 nm. Parameter kimia, seperti jenis, waktu reaksi, dan konsentrasi oksidator, serta pH larutan dioptimasi untuk meningkatkan sensitifitas dan efektifitas waktu analisis. Hasil optimasi metode menunjukkan bahwa hasil optimum diperoleh pada mol rasio oksidator iodat terhadap iodida 1:3, waktu reaksi 5 menit, dan pH larutan 1. Pada kondisi optimum tersebut, metode ini memberikan linieritas pengukuran iodida dari 5-40 mg/L dengan koefisien korelasi (R2) 0,9889. Metode ini menawarkan cara yang sederhana, aman, akurat, dan relatif cepat untuk penentuan iodida yang prospektif untuk monitoring sampel iodida."