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Jurnal Visi Eksakta

eksakta
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Published by Universitas HKBP Nommensen

ISSN : 27233707 EISSN : 27467678 DOI : 10.51622

Core Subject : Health, Science, Agriculture, Engineering,

Agriculture, Biological Sciences & Forestry Automotive Engineering Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Civil Engineering, Building, Construction & Architecture Control & Systems Engineering Electrical & Electronics Engineering Energy Engineering Immunology & microbiology Industrial & Manufacturing Engineering Mechanical Engineering Medicine & Pharmacology Neuroscience Public Health

Jurnal Visi Eksakta adalah jurnal dalam bidang IPA meliputi bidang: Kedokteran, Pertanian, Teknik dan bidang IPA lainnya yang diterbitkan 2 kali dalam setahun Juli dan Januari

Arjuna Subject : Teknik (semua kategori) - Teknik Sipil dan Struktur

Articles 40 Documents

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KAJIAN TERHADAP KARAKTERISTIK PERPINDAHAN PANAS PADA LOOP THERMOSYPHON SEBAGAI ALAT RECOVERY PANAS TEMPERATUR RENDAH Parulian Siagian; Saloom Hilton Siahaan; Lestina Siagian
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

The purpose of this study was to examine the effectiveness of the Loop Thermosyphon Heat Exchanger (LTHE) fluidized R134a refrigerant at variations in working fluid pressure of 0.8MPa and 1.2MPa. Thermosyphon is made of three parts, namely, evaporator, condenser and adiabatic part. Evaporators are made of 3/4 inch diameter copper pipe with a length of 3.5 cm. The condenser is made of 3/4 inch diameter copper pipe with a length of 15 cm. The adiabatic part of the steam line is made of copper pipes with a diameter of 3/4 inches and a length of 25 cm and a liquid line with a diameter of 3/8 inches with a length of 27 cm. Things that were investigated included the effect of air flow velocity (heated fluid) of 0.8 m/s, 1m/s, and 1.2m/s on the effectiveness of LTHE and the effect of an increase in evaporator temperature by 400C, 500C, and 600C on the effectiveness of LTHE. The study was conducted experimentally where the LTHE evaporator was heated with a heater. The results of this study show that the effectiveness of LTHE heat transfer work pressure of 1.2 MPa pressure is about 30-68% and higher than the effectiveness of LTHE heat transfer work pressure of 0.8 MPa pressure about 22-35%. Effectiveness decreases with increasing airflow velocity. The LTHE thermal resistance of 0.8 MPa pressure is around 0.3-0.450C/ W and is greater than the LTHE thermal resistance of 1.2 MPa pressure around 0.08-0.40C /W.

PENINGKATAN KUALITAS PEMBELAJARAN BIOLOGI DENGAN METODE KOOPERATIF DI PRODI PEND. FISIKA FKIP UHN MEDAN Surbakti, Mariana; Panjaitan, Poltak
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

The purpose of this study was to 1) determine student learning outcomes through the Inquiry learning model on metabolic material, 2) know the learning activities of students who were taught with Inquiry learning models in Biology courses, 3) know the psychomotor attitudes of students who were taught with models cooperative learning on metabolic material. This research is an experimental research This research was conducted on physics study students at T.P. 2018/2019. The learning model used is inquiry model in the experimental class and conventional model in the control class.The results showed that: The results of the average value in the control class were: pretest = 45,517 and posttest = 61,896 The results of the average value in the experimental class are: pretest = 48.333 and post test = 80.833 Obtained data X = 80.83; S = 12.32; L hitung = 0.0937; L table = 0.161;then: L calculate <L table, then posttest data Experiment class is normally distributedFrom the results of the statistical calculation above t arithmetic = and t table = 2.003 so as to obtain the value of -2.003 <<2.003 then H0 is accepted, meaning that the initial ability of students in the experimental class is the same as the initial ability of students in the control class.From the results of the statistical calculation above t arithmetic = and t table = 1.6715 to obtain a value of t> t table ie> 1.6715 then H0 is rejected and Ha is accepted meaning there is a significant influence on the use of cooperative learning models on student learning outcomes. The coefficient of linear regression direction ( b) = 0.85 which is positive. This means that the learning outcomes of experimental class student increase due to the influence of the cooperative learning model used in the teaching and learning process in the class.

KAJIAN OPTIMASI JARINGAN GSM DI GEDUNG UTAMA UNIVERSITAS HKBP NOMMENSEN MEDAN Libianko Sianturi; Sindak Hutahuruk
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Network optimization of the GSM - Global System for Mobile Communications aims to ensure the availability, integrity and reliability of such networks. In our study, we are measuring the quality of the signal to determine the condition of quality of signal especially at I and L buildings of Universitas HKBP Nommensen and the LOS (line of sight) conditions between the transceiver raiolink antenna. Based on analysis of the position of the transceiver radiolink antenna, data was obtained that the condition is eligible for Line of Sight (LOS). Based on the value of RxLevel, Rxqual and SQI measurements show that the third value of the parameters indicates better quality. But there are still some locations (rooms) on the 1st floor of building L and building I where the signal quality is slightly worse. To repair SQI in the room Level 1 building I and building L, it is recommended to evaluate and strengthen the power of the iBCMOS sistems that has been applied, especially the indoor antenna that serves on that floors.

PERDARAHAN POSTPARTUM (PERDARAHAN PASKASALIN) Leo Simanjuntak
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Postpartum hemorrhage is the leading cause of maternal death worldwide with 5 – 10% of incidence. The etiology of postpartum hemorrhage are uterine atony, retensio placentae, genital tract laceration, retained placental tissue and coagulation disorders. It was estimated 2 hours period from the onset of postpartum hemorrhage toward the maternal death, meanwhile it was 12 hours in antepartum hemorrhage. It is therefor early diagnosis and prompt management is essential. The solid and skilled teamwork is needed in order to successfully manage postpartum hemorrhage and to avoid maternal death.

PENGEMASAN BUAH DAN SAYUR DENGAN ATMOSFIR TERMODIFIKASI Erika Pardede
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Being living organs, fresh harvested fruits and vegetables remain metabolically active and undergo ripening and senescence processes. They needs oxygen to stay alive, which is vital for energy production through respiration process. Modified Atmosphere Packaging (MAP) technology utilises in-packaging equilibrium atmosphere, in which the relatively low oxygen and high carbondioxide concentration is achieved naturally inside the package as respiration occurs, which later on leads to a lower respiration rate. Low oxygen concentration could also be achieved by replacing some oxygen with nitrogen and/or application of oxygen scavenger inside in package, thus the respiration rate is reduced and the aging process is retarded. The use of packaging films of correct intermediary permiability to meet a desirable equilibrium modified atmosphere become a key to the succes of MAP. A new technique, so called Perforation-Mediated Modified Atmosphere Packaging (PM-MAP), by having microperforation in the plastic films is applied to correct the exchange of air during storage. Therefore Modified Atmosphere Packaging (MAP) technology offers advantages which leads to extension of the shelf life of fresh produces. Fresh and fresh-cut food industry utilise this advantages to meet the growing demand of convinient and fresh quality fruits and vegetables, in order to maintain freshness quality attributes and to extend the shelf life.

BETON BERMUTU DAN RAMAH LINGKUNGAN DENGAN MEMANFAATKAN LIMBAH TONGKOL JAGUNG (Penelitian Laboratorium) Johan Oberlyn Simanjuntak; Tiurma Elita Saragi; Belinauli Teknika Lumban Gaol
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

The need for housing is more higher along with the times and this is also a factor to increasing for concrete needed for building development. The more concrete that is produced, the more cement is needed for construction.Concrete is a composite material (mixture) of several materials, the main ingredient which consists of a mixture of cement, fine aggregate, coarse aggregate, water and or without other additives with a certain ratio. Utilization of waste carried out in this study is to utilize corn cobs waste which is commonly found in the outskirts of the city of Medan. By utilizing this waste, it is hoped that it can reduce the accumulation of corn agricultural waste and also increase public insight about how to treat corn cobs waste into other forms. In this study, a concrete trial was carried out by adding corn cobs ash waste to concrete which aims to find out whether corn cobs ash can increase the compressive strength of concrete with variations in the percentage of the mixture of 0%, 3%, 6%, and 9% of the cement weight. The compressive strength value of normal concrete (25.45MPa), while with the substitution of corn cob ash 3% (21.96 MPa), 6% (18.56MPa), and 9% (16.45MPa). So it can be concluded that the resulting compressive strength exceeds the planned compressive strength and the optimum substitution value of corn cobs varian is at the 3% variant, namely 21.96 MPa.

MENENTUKAN PRODUKSI ENERGI (kWh) PADA PERENCANAAN PEMBANGKIT LISTRIK TENAGA MIKRO HIDRO (PLTMH) SUNGAI AEK SILANG di KABUPATEN HUMBANG HASUNDUTAN Partahi Lumban Gaol; Salomo Simanjuntak
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

This study concerned with designing a micro hydro power generation. The capacity of the plant is calculated on the basis of dependable flow, namely the amount of discharge that is equalled or exceeded during a certain period or with certain probability. Large designed flow have low probability of occurence. Small designed flow is more likely to occur but only produce little electrical power. Designed flow has big influence to production cost of each kWh of power generated. In this study, optimum designed flow is obtained through optimisation of parameter such as cost of producing 1 kWh power from several value of dependable flow. This study conclude that an optimum economic value can be reached by dependable flow of 8,165 m3/s with 45% probability. The cost of producing the power is Rp 557.54 per kWh. The plant generates approximately 64.530.792,94 kWh electrical power in one year.

ANALISA KEBUTUHAN AIR BERSIH PADA DI KOTA BINJAI SUMATERA UTARA Salomo Simanjuntak; Eben Oktavianus Zai; Parto Oktavianus Sihombing
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Human life is very dependent on the fact of good quality air which is called clean water. Clean water is one type of water-based resource that is of good quality and is commonly used by humans for consumption or in carrying out their daily activities including sanitation. The most important thing is clean water is a basic human need that affects human health. Binjai City is a city with a dense population of 283,362 people in 2020, including a small city with a usage of 100 liters / person / day. This requires an analysis of the need for clean water that can be used effectively, efficiently and sustainably. This analysis will require data: the total population obtained from the Central Bureau of Statistics and the existing clean water capacity will be obtained from PDAM Tirtasari as well as literature studies or direct links to related parties regarding the existence of clean water in the city of Binjai. The need for clean water is divided into domestic water needs and non-domestic water needs in which there are social, commercial, industrial, and government agency needs. This need will be projected until 2025 so that Binjai city needs to build a new water treatment plant.

THE EFFECT OF COMPARISON BETWEEN SOYBEAN EXTRACT AND JICAMA EXTRACT AND DURATION OF FERMENTATION ON SOYGHURT QUALITY Benika Naibaho; Handaniel Hutagalung; Samse Pandiangan
Jurnal Visi Eksakta Vol. 1 No. 1 (2020): Jurnal Visi Eksakta : Edisi Juli
Publisher : LPPM Universitas HKBP Nommensen

Soyghurt is a fermented soy milk product using Streptococcus thermophilus and Lactobacillus bulgaricus bacteria. Efforts to enrich drinks high in antioxidants are carried out by combining food ingredients that can function as antioxidants such as soybeans and jicama. The combination of these two food ingredients and the assistance of the fermentation process by S. thermophilus and L. bulgaricans was expected to increase antioxidant activity in soyghurt production.This study used a completely randomized design (CRD) with 2 factors, namely: the first factor was the ratio of soybean juice and yam juice (S) which consisted of 4 treatment levels, namely: S0 = 100: 0, S1 = 75: 25, S2 = 50: 50, S3 = 25: 75, S4 0: 100. Meanwhile for the second factor was the duration of fermentation (F) which consisted of 3 levels of treatment, namely: F0 = 6 hours, F1 = 8 hours, F2 = 10 hours. The parameters observed were total solids, total acid, organoleptic value, antioxidant activity, and total lactic acid bacteria in jicama soyghurt on the best samples.The results showed that both treatment factors had a very significant effect (P <0.01) on total solids, total acid, and organoleptic tests of soyghurt. The study showed that the comparison of soybean juice and jicama juice and fermentation duration resulted a high protein content value of 9.18% and was in accordance with the SNI yoghurt protein content, namely minimum of 3.5%. Antioxidant activity of yam bean soyghurt obtained an IC 50 value of 18.110 mg / L and it was a very strong antioxidant. Total lactic acid bacteria on yam soyghurt was 108 CFU / ml and it was high.Based on this research results, it was suggested that soyghurt processing may use a combination with other types of fruits and use natural food coloring to give different flavors and increase the nutritional values of soyghurt.

PENGARUH PEMBERIAN KULIT BUAH KOPI YANG DIFERMENTASI DENGAN RAGI TEMPE TERHADAP BOBOT POTONG, BOBOT DAN PERSENTASE KARKAS, LAJU DAN pH DIGESTA AYAM BROILER Magdalena Siregar; Ikhlas Bohalima
Jurnal Visi Eksakta Vol. 2 No. 1 (2021): Jurnal Visi Eksakta : Edisi Januari
Publisher : LPPM Universitas HKBP Nommensen

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This study aims to determine the effect of giving coffee skin flour fermented with tempeh yeast in rations on cutting weight, carcass weight, carcass percentage, digesta rate and digesta pH of small intestine of broiler chickens aged 21 and 35 hari. The research method used was a completely randomized design (CRD) with 5 treatments (P0 = control ; P1= 5% ; P2= 10% ; P3=15% and P4= 20%) and each treatment had 4 replications. The results showed that the fermented coffee skin flour had a significant effect (P<0.05) on the cutting weight and carcass percentage, had a very significant effect (P <0.01) on carcass weight, but had no significant effect (P>0.05) on digesta rate and digesta pH of small intestine. The best level giving of coffee skin flour fermented is the level of 15%.

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Widia Sianturi

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widia.sianturi06@gmail.com

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+6285211304551

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visieksakta@uhn.ac.id

Editorial Address
Jalan Sutomo No 4 A Medan

Location
Kota medan,

Sumatera utara

INDONESIA

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Home Page

OAI Link

Editorial Team

Contact

Reviewer

Google Scholar

Contact Name Widia Sianturi

Contact Email widia.sianturi06@gmail.com

Phone +6285211304551

Journal Mail Official visieksakta@uhn.ac.id

Editorial Address Jalan Sutomo No 4 A Medan

Location Kota medan, Sumatera utara INDONESIA

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Contact Name
Widia Sianturi

Contact Email
widia.sianturi06@gmail.com

Phone
+6285211304551

Journal Mail Official
visieksakta@uhn.ac.id

Editorial Address
Jalan Sutomo No 4 A Medan

Location
Kota medan,

Sumatera utara

INDONESIA