Judul: Kajian Beban Pencemaran dan Kualitas Air Sungai Batang Arau di Kota Padang
Abstrak: Development activities in the area of the watershed of a Batang Arau were very intensively with the increase of population that high as the impact of high dynamic of development in the town of the field. Padang has the development of population growth rate 1,09 % according to data from the central bureau of statistics Padang City in 2010. It is in line with the course of economic Padang City. Economic activities of micro agriculture, industry (industry small to large industries) or mining was the backbone of the economy padang. However, with increasing population, development and the economy in padang thought to have an undesired effect negative into the environment are increasing the loads of pollution in the watershed of a Batang Arau in particular the Batang Arau River. The accumulation of the burden of contaminant on the upstream to downstream will make the level of pollution Batang Arau River more tainted. The purpose of this research is a) identify sources contaminant the waters of the Batang arau River at Padang City, b) evaluate developments water quality of the Batang Arau River from upstream to downstream during the period 2008-2012 and c) knowing pollution load any sources contaminant and a capacity of the burden of pollution Batang Arau River. The technique of adoption of the data used in this research is by means of observations, inventorying sources of pollution on the Batang Arau River and an interview with the methods purpossive of sampling. In addition, was also performed by collecting data secondary through the study of literature and examine documents. The condition of the quality of the water of the Batang Arau River analysis based on government regulation of the republic of Indonesia number 82 in 2001. The status of the quality of the water of the uses index the quality of water national sanitation foundation (IKA-NSF). Calculation the pollution loads from various sources contaminant carried out through the approach of rapid assessment of sources of water, polution, water and land while calculation capacity of the burden of pollution according to the decision of the state minister of environment No.110 in 2003. Contaminant sources in Batang Arau River at Padang city is waste from domestic/household, industry, agriculture and mining. Water quality of Batang Arau Rivers was decresing from upstream to downstream. The development of the water quality of Batang Arau River showed that on the upper and middle of the River, the river water quality meets quality raw rods or class II PP 82/2001, while in the downstream river water quality meets quality raw rods or class IV PP 82/2001. Based on the water quality index value, The Batang Or Padang city in 2008-2012 in moderate to good conditions that are in the range of 53-72 in the rainy season and 56-74 during the dry season. The burden of the most heavily contributed to pollution into the Batang Arau River is industrial waste (tons/month 152.905, 9 of BOD, 139.456, 3 ton/month of COD, 124.858 ton/month of TSS and 10.885.106 ton/month of TDS) followed by mining wastes (0 ton/month of BOD, 316.480 ton/month
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Judul: Relationship of Water Quality with Hydrological Parameters in the Downstream of Batang Arau River, West Sumatra for the 2013-2020 Period
Abstrak: Sungai Batang Arau merupakan sungai terpanjang kedua yang melintasi Kota Padang dengan berbagai aktivitas antropogenik yang dapat menurunkan kualitas airnya. Penelitian ini bertujuan menentukan kecenderungan kualitas air hasil pemantauan selama periode 2013-2020 dan menjelaskan korelasi kualitas air dengan parameter hidrologi Sungai Batang Arau, Kota Padang, Sumatera Barat. Data yang dianalisis merupakan data sekunder dari beberapa instansi di Kota Padang. Analisis data didasarkan atas plot grafik antara setiap parameter kualitas air dengan parameter hidrologi (debit dan kecepatan aliran), secara temporal. Juga dilakukan analisis tingkat kesamaan antar stasiun pengamatan dengan analisi kluster atau dendrogram. Hasil analisis menunjukkan adanya korelasi antara antara debit aliran dengan TSS dan BOD, dan antara kecepatan aliran dengan kandungan oksigen terlarut (DO). Debit dan kecepatan aliran sungai berfluktuasi sesuai musim. Kualitas air Sungai Batang Arau cenderung lebih baik pada musim hujan. Sejak tahun 2013, kualitas air sungai cenderung membaik., The Batang Arau River is the second longest river that crosses the city of Padang with various anthropogenic activities that can reduce its water quality. This study aims to determine trends in the quality of monitoring results during of 2013-2020 period and explain the correlation of water quality with hydrological parameters of the Batang Arau River, Padang City, West Sumatra. The data analyzed is secondary data from several agencies in the city of Padang. Data analysis is based on plot graphs between each water quality parameter and hydrological parameters (discharge and flow velocity). Cluster analysis or dendrogram is also used for determining the similarity among observation point. The results of the analysis show that there is a correlation between river discharge and TSS and between river discharge and BOD, and between flow velocity and DO. River discharge and flow velocity fluctuate according to season. The water quality of the Batang Arau River tends to be better in the rainy season. Since 2013, water quality has tended to improve.
Keyword: discharge, flow velocity, river, water quality

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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