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Widya Teknik
Published by Universitas Katolik Widya Mandala Surabaya
ISSN : -     EISSN : -     DOI : -
Core Subject : Engineering,
Chemical Engineering, Chemistry & Bioengineering
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 6 Documents
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Search results for , issue "Vol. 22 No. 2 (2023): November" : 6 Documents clear
Pembangkit Listrik Tenaga Surya Off-Grid dengan Proteksi Baterai Wanimbo, Mina Merry; Gunadhi, Albert; Sitepu, Rasional; Angka, Peter R.; Agustine, Lanny; Alim, Natavijoy; Joewono, Andrew
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.4789

Abstract

Listrik sudah menjadi kebutuhan pokok bagi keperluan rumah tangga, namun banyak daerah di Indonesia yang masih belum terakses listrik PLN. Untuk menghasilkan listrik dapat dilakukan dengan berbagai cara, salah satunya memanfaatkan radiasi cahaya matahari. Sistem Pembangkit Listrik Tenaga Surya memiliki keunggulan dibandingkan dengan pembangkit listrik lainnya, yaitu tidak menimbulkan pencemaran lingkungan, sehingga Pembangkit Listrik Tenaga Surya menjadi solusi yang cocok untuk membuat energi listrik di sektor rumah tinggal. Salah satu sistem yang digunakan pada Pembangkit Listrik Tenaga Surya yang cukup popular adalah sistem off-grid, dimana sistem pembangkit listrik tersebut tidak terkoneksi dengan jaringan PLN, sehingga dibutuhkan baterai (aki) untuk menyimpan energi listrik yang dihasilkan oleh panel surya. Penggunaan aki memiliki aturan agar penggunaannya dapat berlangsung dalam waktu yang lama yaitu Dept of Discharge (DoD) nya tidak boleh tinggi, sehingga dibutuhkan modul tambahan agar melakukan proteksi otomatis. Modul tersebut adalah Low Voltage Disconnect (LVD).Panel Surya yang digunakan memiliki tipe polycrystalline sebanyak 2 x 100 wp. Aki yang digunakan memiliki tipe Valve Regulated Lead Acid (VRLA) dengan spesifikasi 12V 100 Ah, sebanyak 1 buah, dengan menggunakan proteksi LVD. Modul LVD yang digunakan adalah tipe XH-M609 untuk membatasi tegangan dari tegangan terendah aki yang ditentukan, daya dari aki akan dsalurkan ke power inverter dengan daya maksimum 1500 watt.Secara umum,  kinerja sistem PLTS yang dirancang berjalan dengan baik serta dapat digunakan untuk mengaktifkan beban yang direncanakan lampu LED 9watt sebanyak 6 buah selama 4 jam, sesuai dengan kebutuhan.
Detektor Kondisi Psikologis Tubuh Berdasar Suhu Tubuh, Heart Rate dan Galvanis Skin Rensponse yang Terukur pada Tangan Kanan Sinaga, Leon Cicero; Antonia, Diana Lestariningsih; Pranjoto, Hartono; Joewono, Andrew; Gunadhi, Albert; Agustine, Lanny
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.4882

Abstract

Penelitian ini mengembangkan perangkat untuk mendeteksi kondisi psikologis tubuh dalam 3 tingkatan yaitu rileks, tenang dan stres berdasarkan pengukuran suhu tubuh (derajat celcius), heart rate (bpm), dan konduktivitas kulit (GSR) hanya pada pada tangan kanan. Kondisi rileks ditandai dengan suhu tubuh antara 36-37 oC, heart rate antara 60-70 bpm, dan GSR  antara 0,4-1 µmho. Kondisi tenang ditandai dengan suhu tubuh antara 35-35,9 oC, heart rate antara 71-90 bpm, dan GSR  antara 1,1-1,4 µmho. Kondisi stres ditandai dengan suhu tubuh lebih rendah dari 33 oC, heart rate antara 100-140 bpm, dan GSR lebih dari 4,1 µmho. Pengujian perangkat dilakukan pada 4 orang subyek sehat. Kondisi rileks dan tenang disimulasikan dengan pengujian pada subjek sesaat setelah bangun tidur. Kondisi stres disimulasikan dengan pengujian  setelah subyek berolahraga ringan selama 15 menit. Hasil pengujian menunjukkan perangkat dapat mengukur suhu tubuh dan heart rate dengan akurasi 98,7% dan 93,7%. Ketepatan deteksi kondisi psikologis tubuh berdasarkan heart rate dan GSR sudah sesuai desain. Hasil pengujian juga menunjukkan bahwa simulasi olahraga pada orang sehat belum dapat memenuhi rentang parameter suhu tubuh untuk kondisi stres. 
Integration of Rough Cut Capacity Planning (RCCP) and Capacity Constraint Resources (CCR) to Minimize the Risk of Uncertainty in Fulfilling Production Material Supply Salsavira, Nardha Livia; Yuliawati, Evi; Rahmawati, Nur; Trihastuti, Dian
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.4959

Abstract

Managing the production capability of a company is undoubtedly the main concentration in the manufacturing industry. Industries must consider the materials and resources supplied for making a master production schedule. The lack of material supply from a supplier results in the inefficiency of the production process. The supply disruption of raw materials results in problems for the rest of the stages in the production process. As a result, companies experience difficulties in meeting the predetermined target. This research used an integration of RCCP and CCR to solve the problem. Optimization of CCR implies the TOC (theory of constraint) principle by reducing the percentage of overload until reaching a balanced (optimal) condition. This research aims to balance and optimize the ongoing production process. It took place in a manufacturing company that produces building materials serving the market in Indonesia. The results show that during the observation period, the current production system has experienced system overload for about 70% of the production period. The results of the RCCP analysis provide recommendations for improving the master production schedule to increase the effectiveness of the production system.
Antibacterial Activity and Polyphenols Content of Methanolic Extract of Sapindus Rarak Murni, Asmara; Rohman, Aufur; Angkawijaya, Artik Elisa; Santoso, Shella Permatasari
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.5409

Abstract

The study focused on the methanolic extract of lerak fruit (Sapindus rarak DC.). The effect of varying extraction time and temperature on the polyphenols content of lerak extract was evaluated, that is by determining the total phenolic content (TPC), total flavonoid content (TFC), and total saponin content (TSC). The increasing extraction temperature from 30°C to 70°C was found to give increase in TPC from 172 mg GAE/100 mg to 246 mg GAE/100 mg, further increase of extraction temperature to 90°C results in the decrease of TPC. Similar effect was also observed in TFC, where TFC was found to increase as the extraction temperature was increased to 70°C, with TFC of 79 mg QE/100 mg. TSC of lerak fruit extract at 70°C was found to be 17.6 mg/100 g. Antibacterial activity assay on the lerak fruit extract shows the potential inhibitory activity of the extract on the growth of Escherichia coli and Staphylococcus aureus, wherein 95% inhibition efficiency can be achieved after the incubation of the bacteria in media containing 15 wt.% of the extract. The more prominent inhibitory effect of the extract was shown against Escherichia coli than Staphylococcus aureus. Collectively, the results of this study has demonstrated the potential of lerak fruit extract as natural antibacterial agent with foaming ability, which can be used as detergent additive.
Adsorption of Methylene Blue Dye Using Guaran/TiO2 Hydrogel Lee, Tommy; Samsuar, Marcelina; Yuiana, Maria; Santoso, Shella Permatasari
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.5415

Abstract

Natural polysaccharide, namely guar gum (guaran), was utilized as the raw material for preparing hydrogel adsorbent, TiO2 was added into the hydrogel to enhance the adsorption capacity. In this work, methylene blue dye was chosen as the adsorbate model to evaluate the adsorption efficiency of the prepared guaran/TiO2 hydrogel. Several physicochemical characterizations were performed to elucidate the characteristic of the hydrogel, including scanning electron microscopy and Fourier transform infrared spectroscopy. The effect of temperature and pH on the adsorption efficiency of the guaran/TiO2 hydrogel toward methylene blue was evaluated. The result of the study reveals that the use of guaran/TiO2 hydrogel allow 69% removal of methylene blue from solution, and the maximum adsorption capacity was found to be 224 mg/g at system pH of 10 and temperature of 303K. The adsorption process was found to fit with the Langmuir model, indicating homogenous surface energy of the adsorption sites. The evaluation on the thermodynamic parameters of the adsorption indicates the spontaneous and exothermic behavior of the adsorption. This study demonstrated the potential of the guaran for preparing an environmentally friendly hydrogel, which can be a good choice of adsorbent for wastewater treatment.
Preparation of Clay Minerals – Natural Surfactant Composites to Remove Organic Dyes and Heavy Metals Laysandra, Livy; Kurniawan, Darwin; Soetaredjo, Felycia Edi; Ismadji, Suryadi
Widya Teknik Vol. 22 No. 2 (2023): November
Publisher : Fakultas Teknik, Universitas Katolik Widya Mandala Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33508/wt.v22i2.5417

Abstract

The rapid development of industry is considered to be the main cause of various environmental problems, which are mainly caused by the discharge of wastewater which contains many hazardous compounds. Dyes and heavy metals are type of hazardous substances that are often found in industrial wastewater and cause ecosystem damage. Dyes and heavy metals are more difficult to remove due to their inability to be broken down, so they can build up and reach dangerous levels. Adsorption is a straighforward and efficient method for dealing with hazardous substance contamination in water. Clay minerals, known for their efficient adsorption properties, were chosen for this procedure. Clay minerals are porous materials so they are suitable for use as adsorbents. The intercalation technique is a robust strategy to further increase the adsorption capacity of clay minerals, which is done by treating clay minerals with surfactants. Clay minerals modified with natural surfactants are considered as a potential choice for removal procedures. The use of this natural surfactant was chosen because of its excellent adsorption capacity and environmentally friendly properties. Polar lipids, natural surfactants, are commonly present in the lipid layers of plants and animals. This review focuses on the synthesis of modified clay minerals using different natural surfactants such as soybeans, saponins, lipopeptides, and rhamnolipids, as well as the use of alternative clay mineral/natural surfactant composites. This review describe various types of natural surfactants that can be used to modify clay minerals and their application in the adsorption process.

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