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All Journal E-Journal Widya Kesehatan dan Lingkungan Chimica et Natura Acta Scientia: Jurnal Hasil Penelitian JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS (JHSSB) Makara Journal of Technology West Science Agro
Yohan Yohan
The State Ministry of Research and Technology, Gedung II BPPT Lt. 8 – Jl. M.H. Thamrin 8 Jakarta 10340 Faculty of Fishery – University of Satya Negara Indonesia, Jl. Arteri Pondok Indah No. 11 Jakarta 12240
Religion Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Education Electrical & Electronics Engineering Engineering Environmental Science Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mechanical Engineering Public Health Social Sciences Other

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PENGOLAHAN AIR LIMBAH INDUSTRI : PREPARASI DAN KARAKTERISASI KOPOLIMER CANGKOK ASAM AKRILAT PADA FILM HDPE Yohan, Yohan; Nur, Rifaid M.; Hendrajaya, Lilik; Siraj, E. S.
E-Journal Widya Kesehatan dan Lingkungan 2005
Publisher : E-Journal Widya Kesehatan dan Lingkungan

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Abstract

Grafting pre-irradiation process of styrene monomer on high desity poluethylene (HDPE) film for hydrophilic membrane as membrane of cationic exchanger have been done. HDPE film is irradiated by y-ray then grafted by acrylic acid monomer in water. The preparation conditions at which the optimum grafting process are determined, such as rate and total dose of irradiation, monomer concentration, time and temperature of grafting. Characterization of some properties of the prepared grafted membranes were studied and accordingly the possibility of its practical use in fuel cell and in waste water treatment from toxic heavy metals, such as As, Cd, Co, Cu, Fe and Pb was investigated. Good relative condition to graft was using total dose of 45 kGy, dose rate was 7 kGy/hour, acrylic acid was 40% volume, grafting time was 90 minutes, and grafting temperature was 70oC gave percent of grafting HDPE-g-AA = 800-900% weight. The chelated metal ions were easily desorbed by treating the membrane with 0.1N HCl for 2 hours at room temperature. Finally, a mixture of there metals in the same feed solution was used to determine the selectivity of the membrane toward different metals. The results obtained for the prepared membranes showed a promise for their applicability in the removal of heavy metals from industrial wastewater.
DETEKSI URUTAN OLIGONUKLEOTIDA Mycobacterium tuberculosis SECARA VOLTAMMETRI MENGGUNAKAN SCREEN PRINTED CARBON ELECTRODE (SPCE) Hartati, Yeni Wahyuni; Yohan, Yohan; Nurmalasari, Ratna; Gaffar, Shabarni; Lubis, Rubianto A.
Chimica et Natura Acta Vol 4, No 2 (2016)
Publisher : Departemen Kimia

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (204.19 KB) | DOI: 10.24198/cna.v4.n2.10674

Abstract

Mycobacterium tuberculosis merupakan bakteri penyebab tuberkulosis (TB). Pengembangan analisis secara biosensor DNA sangat menarik perhatian karena penerapannya mudah. Dalam penelitian ini telah dilakukan penentuan urutan pendek oligonukleotida M. tuberculosis gen RV0508 dari strain H37RV secara voltammetri pulsa differensial menggunakan screen printed carbon electrode (SPCE). Pendeteksian berdasarkan teknik hibridisasi urutan oligonukleotida probe yang diadsorpsi pada permukaan SPCE, dengan pasangan komplementernya dari DNA target, tanpa indikator hibridisasi, yaitu dengan mensubstitusi basa guanin probe dengan basa inosin. Respon hibridisasi berupa signal guanin DNA target di daerah potensial sekitar +0,9 V. Telah diperoleh korelasi linear antara arus puncak dengan konsentrasi DNA target pada rentang 5,0-20,0 µg/mL dengan batas deteksi 8,2 µg/mL.
Synthesis of Fuel Cell Membrane: Copolymerization of Styrene on ETFE Film by Grafted pre-Irradiation Yohan, Yohan; Nur, Rifai M.; Hendrajaya, Lilik; Siradj, E. S.
Makara Journal of Technology Vol. 9, No. 2
Publisher : UI Scholars Hub

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Abstract

Synthesis of Fuel Cell Membrane: Copolymerization of Styrene on ETFE Film by Grafted pre-Irradiation. Preirradiation Grafting styrene monomer on ETFE film has been prepared. Research has been performed by γ-ray radiation at various total dose from 2.5 – 12.5 kGy and various dose rate from 1.3 – 1.9 kGy/hour. Irradiated copolymer is then grafted by styrene monomer in various solvent: ethanol, 2-propanol, and toluene, various concentration from 20 – 70% volume, various temperature from 50 – 90oC, and various grafting time from 2 – 12 hours. The results showed that percent of grafting is increase with increase of total dose and decrease of rate dose. The optimum experiment conditions are obtained at total dose 10 kGy, dose rate 1,9 kGy/hour, 2-propanol solvent, 40% volume styrene, 4 hours grafting time, and 70oC grafting temperature.
Sulfonation of cPTFE Film grafted Styrene for Proton Exchange Membrane Fuel Cell Yohan, Yohan
Makara Journal of Technology Vol. 11, No. 1
Publisher : UI Scholars Hub

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Abstract

Sulfonation of cPTFE Film grafted Styrene for Proton Exchange Membrane Fuel Cell. Sulfonation of γ-ray iradiated and styrene-grafted crosslinked polytetrafluoroethylene film (cPTFE-g-S film) have been done. The aim of the research is to make hydropyl membrane as proton exchange membrane fuel cell. Sulfonation was prepared with chlorosulfonic acid in chloroethane under various conditions. The impact of the percent of grafting, the concentration of chlorosulfonic acid, the reaction time,and the reaction temperature on the properties of sulfonated film is examinated. The results show that sulfonation of surface-grafted films is incomplete at room temperature. The increasing of concentration of chlorosulfonic acid and reaction temperature accelerates the reaction but they also add favor side reactions. These will lead to decreasing of the ion-exchange capacity, water uptake, and proton conductivity but increasing the resistance to oxidation in a perhidrol solution. The cPTFE-g-SS membrane which is resulted has stability in a H2O2 30% solution for 20 hours.
The Effect of Nutrient Composition on the Growth of Kale Plants in Hydroponic Systems Soelistianto, Farida Arinie; Yohan, Yohan; Suparwata, Dewa Oka; Marjan, M; Amaludin, Moh. Baitullah
West Science Agro Vol. 3 No. 02 (2025): West Science Agro
Publisher : Westscience Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58812/wsa.v3i02.1924

Abstract

This study reviews the impact of nutritional composition on the growth of kale (Brassica oleracea var. acephala) in hydroponic systems, synthesizing findings from 15 Scopus-indexed studies. The analysis highlights the critical roles of macronutrients (nitrogen, phosphorus, potassium) and micronutrients (iron, magnesium, zinc) in optimizing plant growth, yield, and quality. Additionally, it examines the importance of nutrient solution management, including pH, electrical conductivity, and nutrient concentration, for efficient nutrient uptake. Innovative practices such as organic additives and advanced monitoring systems are also discussed for their potential to enhance productivity and sustainability. The review identifies gaps in existing research, particularly in standardizing nutrient formulations and assessing the long-term impact on nutritional quality. These findings provide actionable insights for researchers and practitioners aiming to advance hydroponic kale cultivation.
The Elasticity of Investment and the Number of Productive-Age Population on Economic Growth in Parigi Moutong Regency Wulan, Sri; Nurnaningsih, Nurnaningsih; Yohan, Yohan; Suirlan, Rita; Sading, Yunus
JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS Vol. 4 No. 4 (2025): AUGUST
Publisher : Transpublika Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55047/jhssb.v4i4.1846

Abstract

This research seeks to examine how investment elasticity and the size of the working-age population impact the economic development in Parigi Moutong Regency. The study utilises a quantitative methodology, specifically employing multiple linear regression analysis. The data analysed consist of secondary time series data from 2010 to 2023 sourced from the Central Statistics Agency and other pertinent organisations. The findings of the investigation reveal that investment elasticity positively and significantly influences economic growth, whereas the number of productive-age individuals does not have a notable individual impact. Nonetheless, both factors collectively have a substantial impact on economic growth, as evidenced by a 90.8 percent coefficient of determination. These results shed light that enhancing investments plays a pivotal role in advancing regional economic growth, while strategies for empowering the workforce should be tailored more effectively. This study recommends that local governments integrate investment enhancement policies with human resource quality improvement to achieve inclusive and sustainable economic development.
Analysis of the Determinants of Extreme Poverty in North Morowali Regency Monduu, Elisabet; Suparman, Suparman; Sading, Yunus; Rahman, Failur; Yohan, Yohan
JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS Vol. 4 No. 4 (2025): AUGUST
Publisher : Transpublika Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55047/jhssb.v4i4.1855

Abstract

This study aims to empirically analyse the socio-economic determinants that influence the level of extreme poverty in North Morowali Regency. The main focus of this study lies on three independent variables, namely average length of schooling, life expectancy, and percentage of poor population. Using a quantitative approach, descriptive and verifiable methods were applied to secondary data from 2020–2023 obtained from the Central Statistics Agency (BPS) and related institutions. The analysis was conducted using multiple linear regression accompanied by classical assumption tests and significance testing. The results indicate that all three independent variables significantly influence extreme poverty, with a coefficient of determination (R²) of 0.794. Partially, average years of schooling and life expectancy have a positive and significant effect on reducing extreme poverty, while the percentage of the poor population has a negative and significant effect. These findings indicate that improving the quality of education and health is key to reducing extreme poverty, while high levels of general poverty exacerbate extreme poverty. The implication of this study is the importance of evidence-based regional policy formulation that focuses on comprehensive human development. The originality of this research lies in its approach, which integrates human development indicators into a model for measuring extreme poverty at the district level specifically.
Elasticity of Growth in the Processing Industry Towards the Contribution of Labour Absorption in the Processing Industry in the City of Palu Alfiana, Alfiana; Nurnaningsih, Nurnaningsih; Sading, Yunus; Paembonan, Laendatu; Yohan, Yohan
JOURNAL OF HUMANITIES, SOCIAL SCIENCES AND BUSINESS Vol. 4 No. 4 (2025): AUGUST
Publisher : Transpublika Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55047/jhssb.v4i4.1915

Abstract

The manufacturing sector is a strategic pillar of regional economic development due to its significant role in generating added value and creating employment opportunities. However, in Palu City, the growth of this sector has not consistently translated into proportional increases in employment absorption. This study aims to analyze the elasticity of manufacturing sector growth with respect to its contribution to employment absorption in Palu City over the period 2019–2023. A descriptive quantitative approach was employed, utilizing secondary data obtained from the Central Bureau of Statistics (BPS) of Palu City and relevant agencies. The data set comprises the manufacturing sector’s Gross Regional Domestic Product (GRDP), the number of workers in the manufacturing sector, and the total workforce in Palu City. The analysis involved calculating both output and employment growth rates, followed by the computation of labor absorption elasticity using the elasticity ratio formula. The results reveal that the relationship between manufacturing output growth and employment absorption in Palu City is volatile and not always proportional, as indicated by the elasticity measurements of manufacturing GRDP growth relative to employment growth in the sector. Certain years recorded negative elasticity values, reflecting inverse relationships driven by internal sectoral dynamics such as efficiency gains, technological adoption, and external shocks including the COVID-19 pandemic. The study concludes that although the manufacturing sector makes a substantial contribution to economic growth, its impact on job creation remains suboptimal. As such, integrated policies are needed to align industrial growth with sustainable employment and improve regional welfare.
The Impacts of Academic Services and Campus Atmosphere to Students’ Satisfaction and Retention Yohan, Yohan
Scientia: Jurnal Hasil Penelitian Vol. 3 No. 2 (2018): Scientia
Publisher : LP2M IAIN Syaikh Abdurrahman Siddik Bangka Belitung

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (436.259 KB) | DOI: 10.32923/sci.v3i2.1328

Abstract

Pelayanan akademik dan suasana kampus merupakan dua hal yang seringkali dapat menganggu kenyamanan dan kepuasan mahasiswa dalam proses penyelesaian kuliah. Melalui kajian yang dilakukan didapati bahwa dampak dari pelayanan kampus yang kurang prima dan suasana kampus yang kurang mendukung menyebabkan banyak mahasiswa yang merasa tidak nyaman berada di kampus dan tidak betah berlama-lama berada di dalam kelas. Disamping itu, terdapat beberapa dosen yang gagal memenuhi jumlah minimal kehadiran kelas. Sedangkan aktifitas konsultasi akademik yang dapat dimanfaatkan sebagai wadah dalam menyampaikan pesan-pesan akademik bagi keberhasilan mahasiswa belum sepenuhnya dimaksimalkan oleh sejumlah dosen dan juga mahasiswa yang bersangkutan. Akibatnya muncul ‘mis-komunikasi,’ sehingga banyak mahasiswa yang gagal meraih kepuasan dan kenyamanan akademik. Padahal kepuasan akademik dan kenyamanan dalam proses perkuliahan merupakan pendorong kesuksesan akademik mereka guna menghindari kegagalan penyelesaian kuliah. Oleh sebab itu diharapkan agar pihak yang berkompeten di kampus dapat meningkatkan pelayanan yang lebih prima dan mendorong para dosen, mahasiswa dan seluruh civitas akademikanya untuk terlibat secara aktif dalam membangun sekolah tinggi ini bagi kemajuan masa depan kampus agar dapat meminimalisir mahasiswa yang ‘drop out’ dengan menutup segala kekurangan yang ada.
Co-Authors Alfiana Alfiana Amaludin, Moh. Baitullah Dewa Oka Suparwata E. S. Siradj E. S. Siraj Failur Rahman Laendatu Paembonan Lilik Hendrajaya Lubis, Rubianto A. Marjan, M Monduu, Elisabet Nur, Rifai M. Nurmalasari, Ratna Nurnaningsih Nurnaningsih Rifaid M. Nur Rifaid Nur, Rifaid Rita Suirlan Shabarni Gaffar -, Shabarni Gaffar Soelistianto, Farida Arinie Sri Wulan, Sri Suparman Suparman Yeni Wahyuni Hartati Yunus Sading