Self-purification process is an important process in the effort of recovering the river condition itself. This process usually takes place naturally. However, several inhibitions might disturb the process. It was indicated by the slow deoxygenation rate and unhealthy river condition. This research aims to identify the influence parameters responsible for the slow of self-purification in the Cikapundung River, which is located in the urban area of Bandung City, Indonesia. The river water samples were taken and analyzed in the laboratory to obtain the water quality. The deoxygenation rate was also calculated based on the Slope Method after data was acquired from 10 days daily observation. Research showed that the value of urban river deoxygenation rate is relatively low. The low value of the rate of deoxygenation led to the difficulty in rivers to purify themselves. Pollutants inhibiting the process include phenol, detergent, and heavy metals, which are contaminating the river over the maximum standard. Biologically, the decomposer consists in the river is few. It leads to a slow organic degradation rate. The condition is representing the low capacity of self-purification of the Cikapundung River which is caused mainly by chemical and biological parameters.

<span id="docs-internal-guid-9f43cecc-7fff-332e-09a3-ed0af9ff66fe"><span>River water quality modeling needs appropriate and suitable coefficients especially in application for specific river like urban river. </span><span>Aim:</span><span> This study aims to determine the value of the coefficient with a short term duration and a variable test time span.  Several ways and methods of determining the rate of deoxygenation are developed according to the characteristics of the river and the environment. Modification method was applied in this research in which the test time span was unequal. The river chosen in this study is the Citepus River, Bandung, Indonesia representing an urban river in a tropical country. </span><span>Methodology and Results:</span><span> Sampling was carried out in the dry season. The laboratory analysis method used in determining the rate of deoxygenation uses the Slope Method of data from the short term incubation, which is ten days. The results showed that the Thomas Slope method's deoxygenation rate (K1) was 0.095 per day in the upstream segment, 0.917 per day in the middle segment, and 0.180 per day in the downstream segment. While the Ultimate BOD (La) value is 46.95 mg/l in the upstream segment, 38.70 mg/l in the middle segment, and 37.60 mg/l in the downstream segment. </span><span>Conclusion, significance, and impact of study:</span><span> The results of this study show that the value of the deoxygenation rate is similar to the theoretical surface water conditions. However, in the upstream segment, there is still a low deoxygenation rate value due to non-optimal activity of microorganisms. This findings will be very useful both in water quality modeling and river management.</span></span>

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Penelitian ini bertujuan untuk mengetahui penggunaan media pembelajaran MIVI dalam meningkatkan hasil belajar siswa pada topik sistem gerak manusia. Metode penelitian yang digunakan adalah Metode Experiment dengan menggunakan rancangan penelitian Pre-Experimental Design dengan desain penelitian One-Group Pretest-Posttest Design. Subjek dari penelitian ini ditentukan dengan teknik purpossive sampling yaitu siswa kelas XI MIA-7 di SMA Negeri 20 Bandung pada semester ganjil tahun ajaran 2017-2018. Hasil penelitian pada aspek kognitif didapatkan skor rata-rata Pretest sebesar 42,70 dan skor rata-rata Posttest sebesar 82,46 serta dari hasil uji N-Gain didapatkan skor sebesar 0,69 dengan kategori sedang. Kemudian, hasil penelitian pada aspek afektif mendapatkan skor rata-rata sebesar 85 dengan kategori baik dan aspek psikomotor mendapatkan skor rata-rata sebesar 86 dengan kategori sangat baik. Sedangkan, hasil angket dari keseluruhan siswa didapatkan respon positif sebesar 79% dengan kategori hampir seluruhnya. Dari data hasil penelitian tersebut dapat disimpulkan bahwa penggunaan media pembelajaran MIVI dapat meningkatkan hasil belajar siswa pada topik sistem gerak manusia. Kata kunci: Hasil belajar Media interaktif visual Media pembelajaran MIVI Sistem gerak manusia ABSTRACT Key word: Students learning outcomes Interactive visual media Instructional media MIVI Human mechanical system The use of MIVI (Media Interaktif Visual) learning media to increase the students' learning outcomes in the human mechanical system topic. The aim of this research is to explore the use of MIVI learning media in the increasing of students' learning outcomes in the human mechanical system topic. This research uses Pre-Experiment Design method with using research design of One-Group Pretest-Posttest Design. The subjects in this research are determined by purposive sampling technic; they are students of XI MIA-7 SMA Negeri 20 Bandung in the 2017-2018 school year. The result of this research shows that in the cognitive aspect get the average point Pretest is 42,70 and Posttest is 82,46 and then the test result of N-Gain is 42,70 as medium category. Thus, the result of this research in affective aspect gets 85 point in average as well category and psychomotor gets 86 in average as very well category. Whereas, from all the students' questionnaire get positive result that is 79% with all categories. From all those data of this research conclude that the use of MIVI learning media can increase the students' learning outcomes in the human mechanical system topic.

Citarum River is a river that passes in the Purwakarta City at its middle segment. The riverbank is overflowing with people's houses with its wastewater outlet leading directly to the river. Various efforts can be implemented in order to improve the environmental conditions of the Citarum River. One of the activities that can be conducted is the prediction of water quality through the modeling of river quality. This domestic waste polluted river model generally uses BOD and DO equations which require the coefficient of deoxygenation rate in its calculations. This study aims to determine the value of the coefficient of deoxygenation rate using the method of laboratory experiment and using the empirical formula. The coefficient will gives more accurate result of urban river quality modeling. Samplings were carried out at two locations that are considered to represent river condition. The laboratory analysis method used in the calculation of deoxygenation rate is using Winkler Method and Slope Method, while Empirical Formula is used in calculating deoxygenation rate using Hydroscience Equation. The results of the analysis and calculations show that the value of the deoxygenation rate range (K1) in the middle segment of Citarum River ranges from 0.10 to 0.17 per day and the BOD Ultimate (La) concentration ranges from 18.46 to 24.43 mg/L. As for the value of deoxygenation rate range (K1) on Citarum River using empirical formula ranged from 0.270 to 0.278 per day. The difference in value can be attributed to the actual deoxygenation rate in the Citarum River is hampered by the factors that disrupt the process of decomposition of organic matter and its capability on self purification process.