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PEMODELAN UPAH MINIMUM KABUPATEN/KOTA DI JAWA TENGAH BERDASARKAN FAKTOR-FAKTOR YANG MEMPENGARUHINYA MENGGUNAKAN REGRESI RIDGE Hildawati Hildawati; Agus Rusgiyono; Sudarno Sudarno
Jurnal Gaussian Vol 5, No 1 (2016): Jurnal Gaussian
Publisher : Department of Statistics, Faculty of Science and Mathematics, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (543.998 KB) | DOI: 10.14710/j.gauss.v5i1.11035

Abstract

The least squares method is a regression parameter estimation method for simple linear regression and multiple linear regression. This method produces no bias and variance estimator minimum if no multicollinearity. But if it happens, it will generate a large variance and covariance. One way to overcome this problem is by using ridge regression. Ridge regression is a modification of the least squares by adding a bias constant  on the main diagonal Z'Z. So that estimation parameter  with . This method produces bias and variance estimator minimum. Results of the modeling discussion of minimum wage in the city of Semarang, Surakarta, Tegal and Banyumas as well as the factors that influence it, such as inflation, Gross Domestic Regional Product (DGRP) and the Desent Living Needs contained multicollinearity problem. The minimum wage is significantly influenced Semarang Desent Living Needs, while Surakarta and Banyumas significantly affected GDRP and Desent Living Needs. Keywords: multicollinearity, ridge regression, bias constants , the minimum wage
PERAMALAN DINAMIS PRODUKSI PADI DI JAWA TENGAH MENGGUNAKAN METODE KOYCK DAN ALMON Firdha Rahmatika Pratami; Sudarno Sudarno; Dwi Ispriyanti
Jurnal Gaussian Vol 5, No 1 (2016): Jurnal Gaussian
Publisher : Department of Statistics, Faculty of Science and Mathematics, Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (558.564 KB) | DOI: 10.14710/j.gauss.v5i1.11032

Abstract

Paddy is one of the staple crops that have strategic value and has a great influence in economic, environmental, social and political. Almost of Indonesia's population consumes rice every day. Because of that, need models to determine or predict the amount of paddy production in Central Java for the future. Because the data used is the historical data, there will be a regression analysis that takes into account the time. If the regression model include not only the value of the independent variable X at this time, but also the value of the past (lagged), this model  called a distributed-lag model. The methods used in determining the equation of distributed-lag are Koyck and Almon method. Koyck method used to determine the estimated dynamic model of distributed-lag time difference (lag) is unknown. Almon method used to determine the estimated dynamic model of distributed-lag time difference (lag) is known. Selection of the best model is using Mean Absolut Percentage Error criteria. According the result of the analysis, using Almon model has better result than Koyck Model.Keyword: Paddy, Distributed-lag model, Koyck, Almon
DURABILITAS CAMPURAN HOT ROLLED SHEET-WEARING COURSE (HRS-WC) AKIBAT RENDAMAN MENERUS DAN BERKALA AIR ROB Nahyo Nahyo; Sudarno Sudarno; Bagus Hario Setiadji
Jurnal Teknik Sipil Unaya Vol 1, No 2 (2015): Juli 2015
Publisher : Center for Research and Community Service (LPPM) University of Abulyatama

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30601/jtsu.v1i2.14

Abstract

Tide phenomenon that often occurs in the coastal areas of Indonesia resulted in flooding, which is called the tidal flood. A tidal flood overflow phenomenon of sea water inland. Often some of the roads located in coastal areas are flooded by tidal flood and often causing some damages to the road. Therefore it is necessary to investigate the effect caused by tidal inundation or water bath for asphalt pavement.This research aims to know the durability performance of asphalt concrete mixtures with marinade modification Marshall. The study was conducted with two standard methods of soaking in tidal water and laboratory. Water Immersion method is made by soaking continuous (continuous) and periodic (intermittent). Soaking the specimen in water tidal variation within 6 hours; 12 hours; 24 hours; 48 hours; and 72 hours. While the periodic immersion done by soaking the specimen for 12 hours, then removed during the next 12 hours during 3-days. To view the durability performance of asphalt concrete mixtures used indicator Index of Retained Stability (IRS), Stability Deformation Index, namely First Durability Index (IDP), and the Second Durability Index (IDK).The results showed that continuous immersion damage effects mix quicker on asphalt mixtures than regular immersion. Tidal water used to soak the asphalt mixture Hot Rolled Sheet-Wearing Course (HRS-WC) either continuous or periodic method, has a greater influence than the use of laboratory water. It is shown by the value of the durability of asphalt mixture soaked-tidal water smaller than water-soaked asphalt mixture laboratory standards.
Solar-Powered Electrocoagulation System for Tofu Wastewater Treatment and its Characteristic Muryanto Muryanto; Ajeng Arum Sari; Sunu Pertiwi; Danar Aji Prasetyo; Sudarno Sudarno
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 18, No 2 (2021): July 2021
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (474.787 KB) | DOI: 10.14710/presipitasi.v18i2.338-348

Abstract

This study aims to investigate the ability of solar-powered electrocoagulation for tofu wastewater, especially for reducing COD and TSS. This feasibility was compared with conventional electrocoagulation using electricity from the state electricity company. The study was conducted on a laboratory scale using a batch reactor electrocoagulation and aluminium electrode. The types of electrolytes used are sodium chloride and potassium chloride. The contact time is 0, 2, 4, 6, and 8 hours. The results showed that removal of COD and TSS in tofu wastewater increases with a longer electrolysis time. During two hours of electrolysis time, the removal of COD and TSS were 25 and 53.85%, respectively. This process yielded the highest COD and TSS removal of 75 and 76.9%, respectively, at 6 hours. Pseudo-second order kinetics about COD removal, both in conventional and solar panel systems, is concluded. By adding NaCl electrolytes, the conductivity of wastewater was increased, and then the removal of COD and TSS was also increased. At the end of the electrolysis time (5 hours), the pH of wastewater was neutral. The results of sludge characterization using FTIR showed the presence of hydroxyl groups, amide compound, and aromatic compound.  The process of using solar panels gives results slightly different from conventional electricity, but has advantages in terms of lower operating costs and environmental friendly.
Removal Efficiency of Chemical Oxygen Demand on Greywater using Multi Soil Layering (MSL) Technology Syafrudin Syafrudin; Mochtar Hadiwidodo; Irawan Wisnu Wardhana; Tika Ayu Kusuma Wardani; Indah Sekar Arumdani; Sudarno Sudarno; Nurandani Hardyanti
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 18, No 2 (2021): July 2021
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (305.248 KB) | DOI: 10.14710/presipitasi.v18i2.299-305

Abstract

Greywater is household waste sourced from kitchens and bathrooms, except for toilets. Around 58%-85% of greywater can be generated from the total volume of household wastewater per house. It is necessary to treat wastewater before it is discharged into water bodies to prevent the adverse effects of contaminants on the environment and human health while reducing the demand for clean water. However, due to environmentally friendly, socially sustainable, and economical treatment costs, considering that greywater is produced every day and continuously, Multi Soil Layering (MSL) technology can be an alternative to remove contaminants in water. Thus, this study aims to determine the migration of COD in greywater using MSL technology. Other parameters tested were pH and temperature by taking samples of wastewater in residential areas of Semarang City. In this study, there are two stages, namely the preliminary stage and the running stage. The MSL system will use three reactors with andosol soil, apus bamboo, and coconut shell activated charcoal as mixed soil blocks (SMB). Reactor A (activated charcoal and andosol soil), reactor B (bamboo apus and andosol soil), reactor C (andosol soil, bamboo apus, activated charcoal). The results of domestic wastewater treatment using the MSL method in each of the three reactors could remove COD by 75%, 74%, and 76%. Reactor C obtained the highest COD removal efficiency compared to other reactors.
Waste Collection and Transport Optimization of Pemalang District Service Area, Pemalang Regency Adranandini Noor Anisa; Mochtar Hadiwidodo; Sudarno Sudarno; Sri Sumiyati
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 19, No 3 (2022): November 2022
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/presipitasi.v19i3.687-700

Abstract

This study was prepared with the aim to plan the optimum transportation system in Pemalang sub-district based on traffic conditions in accordance with the desired target. The method used in this planning uses GIS-based applications, namely network analyst and google map. The operational cost of the vehicle in this planning is calculated by the PCI (Pacific Consultant International) method. Based on existing conditions, the operational costs of vehicles incurred reached Rp2,361,445,231.21 while in optimization conditions the operational costs incurred became more efficient at Rp2,913,093,684.31. The optimum time of transportation is done at 05.00 – 12.00 to avoid peak traffic hours at 13.00 – 17.00 with a vehicle travel speed of 47.42 km/h. Addition of freight after optimization so that it becomes 50 freight/day and the addition of containers to 9 containers. It was obtained for 2021 - 2025 as many as 17 containers as well as the addition of freight as many as 15 freight, and 6 fleets of armroll truck carriers.
The Moisture Content of Sawdust Fuel Pellets at Different Drying Periods Junaidi Junaidi; Yustina Metanoia Pusparizkita; Attaya Juliatiko; Ngakan Ade Rahmadiputra; Sudarno Sudarno
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 19, No 3 (2022): November 2022
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/presipitasi.v19i3.599-606

Abstract

The development of pellet fuel from biomass has a great opportunity because Indonesia is an agricultural country. Utilizing this biomass can increase economic value, minimize waste generated, and reduce emissions released into the environment. In this study, the pellet fuel was made from sawdust obtained from the Semarang wood sawmill industry. The raw materials are mixed with adhesive, water and then formed using a pellet machine. The high water content in the pellets that have just come out of the pelletizing (27%) process requires drying treatment. The aim of this work was to find out the effect of drying time on the moisture content of the pellet fuel to meet existing standards. The variation of drying time used is 10, 15 and 20 minutes at 100° C. The results showed that the moisture content of the pellet was 22% (10 min), 19% (15 min) and 17% (20 min). The water content in the pellets will decrease 4% on average along with the drying time. However, the water content was still slightly higher than the specified standard (8-13%). Based on model predictions, the necessary drying time is 30-35 min. Ash content obtained from this study is 0.7%. The drying time can affect the density of the resulting pellet product.  Accordingly, further studies are needed to determine the drying optimum temperature.
Organic Solid Waste Management by Producing Eco-Enzymes from Fruit Skin in Permata Tembalang Budi Prasetyo Samadikun; Sudarno Sudarno; Yustina Metanoia Pusparizkita; Nurandani Hardyanti; Fathan Syahreza Pratama; Rahayu Puji Safitri
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 20, No 1 (2023): March 2023
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/presipitasi.v20i1.21-30

Abstract

The Ministry of Environment and Forestry in 2020 estimates that waste dumps in Indonesia will be 67.8 million tons. However, organic waste management in Indonesia is still relatively low. The accumulation of organic waste in the landfill, which usually causes unpleasant odors and potentially cause an explosion due to the production of methane gas from natural decomposition processes, can be avoided by prioritizing waste management from the source. An alternative way to handle organic waste is make eco-enzymes because it is efficient, economical, and environmentally friendly. This is the focus of the community service team. The community service method is carried out in three stages, including the preparation stage, the implementation stage, and the final stage. The preparation stage consists of doing a module for sorting organic waste and its utilization (making eco-enzymes). The next phase consists of socialization, education, and training on sorting organic waste and making the right eco-enzymes. The final stage consists of evaluation and making a final report. The expected result after education, socialization, or training has been carried out by the community service team, the community members, especially RT 04      RW 05 Permata Tembalang, know better and understand the sorting and utilization of organic waste. 
Nutrient Recovery from Agricultural Waste Water Using Electrocoagulation Process, A Case Study of Thekelan, Semarang, Indonesia Mochamad Arief Budihardjo; Sudarno Sudarno; Ika Bagus Priyambada; Amin Chegenizadeh; Purwono Purwono
Jurnal Presipitasi : Media Komunikasi dan Pengembangan Teknik Lingkungan Vol 20, No 1 (2023): March 2023
Publisher : Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14710/presipitasi.v20i1.44-52

Abstract

Eutrophication is a natural phenomenon in aquatic ecosystems that causes algae and other aquatic plants to overproduce. This process can benefit the ecology in tiny amounts, but too many nutrients can generate hazardous algal blooms and kill fish and other aquatic life. To prevent eutrophication and sustain aquatic ecosystems, agricultural waste water like microalgae production wastewater must be treated. The goal of the project is to get nitrogen and phosphorus out of the wastewater from growing microalgae, which is an agricultural waste water. One way to recover nutrients from wastewater is electrocoagulation. This procedure uses an electric current to create microscopic gas bubbles that collect and remove pollutants from wastewater. According to this study, electrocoagulation reduces phosphate and nitrate in microalgae culture wastewater. Phosphate concentration dropped by 90.20% in the 15th minute, while nitrate concentration dropped by 36.19% in the 30th minute. These reductions may be caused by struvite formation and nitrate conversion to nitrogen gas. This study demonstrates that electrocoagulation is a potential technology for recovering nutrients from agricultural waste water and reducing aquatic ecosystem eutrophication.