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All Journal Peronema Forestry Science Journal Jurnal Ilmiah Mahasiswa FEB Academy of Education Journal Jurnal Mekanova : Mekanikal, Inovasi dan Teknologi Cahaya bagaskara
Luthfi Hakim
Departemen Kehutanan, Fakultas Pertanian, Universitas Sumatera Utara, Medan 20155, Indonesia
Aerospace Engineering Agriculture, Biological Sciences & Forestry Automotive Engineering Control & Systems Engineering Education Electrical & Electronics Engineering Engineering Industrial & Manufacturing Engineering Mechanical Engineering Social Sciences Other

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Simulasi Numerik Aliran Melintasi Backward Facing Step Dengan Penambahan Rectangular Bump Syurkarni Ali; Luthfi Hakim
Jurnal Mekanova: Mekanikal, Inovasi dan Teknologi Vol 5, No 1 (2019): April
Publisher : universitas teuku umar

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1499.431 KB) | DOI: 10.35308/jmkn.v5i1.1622

Abstract

Rectangular bump merupakan salah satu jenis pengganggu atau turbulator dengan tujuan mengganggu aliran supaya aliran menjadi turbulen lebih awal sebelum daerah recirculaion  flow.  Penelitian  ini  dilakukan  untuk  mendapatkan  informasi  mengenaifenomena aliran yang melewati backward facing step setelah dilakukan penambahan rectangular bump didepan daerah recirculation. Rectangular bump ditempakan dengan jarak yang berbeda (s/d = 0,5 dan s/d = 2) dengan harapan bisa memprediksi Reattachmen lenght, menghitung  nilai Coefficient pressure (Cp)  dan  Skin  friction  coefficient  (Cf). Penelitian dilakukan secara numerik menggunakan perangkat lunak Computational Fluid Dinamics (CFD) komersial. Dengan memilih berbagai model turbulensi, yaitu modelStandard k-� (SKE), model Realisable k-� (RKE), model Standard k-???? (SKW) dan model Shear-Stress-Transport (SST) k-???? (SSTKW).
The Influence of Organizational Culture and Work Stress on Work Satisfaction of The Employee (Study of University of Brawijaya Malang) Luthfi Hakim; Dodi W. Irawanto
Jurnal Ilmiah Mahasiswa FEB Vol 2, No 2: Semester Genap 2013/2014
Publisher : Fakultas Ekonomi dan Bisnis Universitas Brawijaya

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Abstract

The objective of research is to analyze the influence of organizational culture and work stress on work satisfaction of the employee of University of Brawijaya Malang. The expected result is whether organizational culture and work stress influence work satisfaction. The supportive organizational culture and the appropriate management of work stress will give good impact on work satisfaction of the employee. Research design is causal (cause and effect) which aims at explaining the causal relationship between research variables through hypothesis testing. Data of research are obtained through interview with informants, questionnaire and observation. The sample includes 104 respondents. Method to collect data from respondents is questionnaire with Likert Scale. Data analysis involves classical assumption test and multiple linear regression analysis. The processing of data is facilitated by SPSS Version 21 to understand the influence of organizational culture and work stress on work satisfaction of the administration employee of University of Brawijaya Malang. Independent variables in this research are organizational culture (X1) and work stress (X2), while dependent variable is work satisfaction (Y). Result of research based on the analysis over the data and the hypothesis testing has indicated that organizational culture (X1) and work stress (X2) are simultaneously and partially influencing significantly on work satisfaction (Y). One independent variable with the dominant influence on dependent variable is work stress (X2). It means that work stress experienced by the employee of University of Brawijaya Malang shall be minimized through manners and methods available to increase work satisfaction felt by the employee of University of Brawijaya Malang.
Pengembangan Perekat Likuida dari Limbah Kulit Buah Kakao (Theobroma cacao L.) Marcelila Medynda; Tito Sucipto; Luthfi Hakim
Peronema Forestry Science Journal Vol 1, No 1 (2012): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (437.753 KB)

Abstract

Increased need for adhesive in the wood processing industry require alternative to meet the needs. Cocoa is one of natural resource that contains lignocelluloses and potential to be alternative adhesive through liquefaction process. This research aim to determine adhesive quality such as visible, degree of acidity (pH), viscosity, density, solid content, gelatin time, ash content , free formaldehyde, and crystalline degree, compare the adhesive quality of cocoa fruit outer skin (CFOS/ KBKL) and inner skin (CFIS/ KBKD), and compare them with SNI 06-4567-1998. Mixed cocoa fruit skin, H2SO4, technical crystal phenol, NaOH and formalin with 90ºC temperature for 2 hours. Result of research showed that cocoa fruit skin adhesive is phenolic group with CFOS was liquid adhesive characteristic, brown colored, waste free, degree of acidity was 10, viscosity was 0,8355 cps, density was 1,156, degree of solid content was 42,33%, gelatin time was 89 minutes 37 seconds, ash content was 9,2%, free formaldehyde was 0,8% and crystalline degree was 35,19% and CFIS characteristic was liquid, reddish brown colored, waste free, degree of acidity was 10, viscosity was 31,202 cps, density was 1,262, degree of solid content was 44,66%, gelatin time was 73 minutes 45 seconds, ash content was 13,8%, free formaldehyde was 0,48% and crystalline degree was 37,28%. CFIS better than CFOS because it has fit with the standards well and also almost standard approach although not according to standard. Cocoa fruit skin liquid adhesive quality were gotten fulfilled SNI 06-4567-1998 enough such as appearance, degree of acidity, degree of solid content and gelatin time. Free formaldehyde characteristic also fulfill of SNI 06-4565-1998 was ≤2% Key word: waste, cocoa fruit outer and inner skin, liquiefaction, wood liquid adhesive
ASETILASI KAYU KEMIRI (Aleurites moluccana), DURIAN (Durio zibethinus), DAN MANGGIS (Garcinia mangostana) Febrina Heryani Tarigan; Luthfi Hakim; Rudi Hartono
Peronema Forestry Science Journal Vol 1, No 1 (2012): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

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Abstract

The problem solve of unstable dimensions wood fruits and susceptible wood from termites attack was an attempt preservation of wood by acetylation. The research purposes were to knew the effect of wood variety and acetic acid concentration to retention value, to evaluated the Weight Percent Gain (WPG) and dimention stability, and to evaluated durability from attack termite based on laboratory dan grave yard test. Some kind of wood such as kemiri, durian, and manggis woods were treated by soaking during 2 weeks with acetic acid concentration of 10%, 15%, 20%, and 25%. The results showed that high retention on kemiri wood with concentration of 25% was 7.73 gr/cm3. Durian wood in concentration of 15% had WPG value (44.41%) was good dimention stability (67.8%). The increasing of acetic acid concentration caused the increasing of retention and wood resistance from termite attack in laboratory and grave yard test. Key words: acetic acid, wood acetylation, termites, WPG, ASE
Asetilasi Kayu Rambutan (Nephelium lappaceum L), Cempedak (Artocarpus integer Merr), dan Rambai (Baccaurea montleyana Muell. Arg) Jendro Zalukhu; Luthfi Hakim; Rudi Hartono
Peronema Forestry Science Journal Vol 1, No 1 (2012): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

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Abstract

The utilization of fruit woods increased according of increasing human needs. Several weakness of fruit woods were bad dimensional stability and susceptible wood from termite attack. Preservation can improve the dimensional stability and increase the wood from termite attack. One preservation method of was acetylation. The research purpose were to known the effect of rambutan, cempedak and rambai woods variety and acetic acid concentration to retention value, to evaluated the dimention stability and Weight Percent Gain and to evaluated durability from attack termite based on graveyard test and laboratory test. Some kind of wood such as rambutan, cempedak and rambai woods were treated by soaking during 2 weeks with acetic acid concentration of 10%, 15%, 20% and 25%. The results showed the effective retention on rambai wood with concentration of 20% was 3.81%. The high dimention stability ASE on rambutan wood with concentration of 15% was 73.37%, and the high WPG on rambai wood with concentration of 25% was 46.66%. The increasing of acetid acid concentration caused the increasing retention and wood resistance from termite attack in graveyard test and laboratory test. Key words: Wood, acetylation, ASE, WPG, termite
Sifat Fisis dan Keawetan Alami Kayu Pengkih Terhadap Serangan Rayap Tanah (Macrotermes Gilvus) Jon Herianta Ginting; yunus afifuddin; Luthfi Hakim
Peronema Forestry Science Journal Vol 1, No 1 (2012): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (408.342 KB)

Abstract

Availability of wood species from natural forest that commonly used for building contructions, meuble, craft and industrial materials nowadays is increasingly limited and not balanced with increasing the needs of wood. To fulfill the needs should be used the species of wood that easily obtained, such as the species that are less well known from natural forest or cultivated by people. The purpose of this research is to evaluate the physical propersties and natural durability of pengkih wood towards termite attack. These physical properties testing is based on the ASTM D 143-94 standard with three replications in each sample. These natural durability of wood testing based on the SNI 01-7207-2006 standard with four replications in each sample. Based on the results of this research pengkih wood is including class II of wood strength, that have value of density substance is 1.5 and including class I of grade durability with percentage of weight lose about 0.3-0.6%. The smallest value of attack intensity is in the  wooden base and the largest is in the end of the wood. .   Key words : Pengkih Wood, physical  properties, natural  durability, termites
Kualitas Papan Semen dari Partikel Serutan Pensil dengan Berbagai Rasio Semen dan Partikel Desi Natarina Sembiring; Luthfi Hakim; Tito Sucipto
Peronema Forestry Science Journal Vol 4, No 2 (2015): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

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Abstract

Cement-Bonded Particleboard made of pencil shaving industry waste has not developed in Indonesian. The main objective of this research was to evaluate the physical and mechanical properties of cement bonded from pencil shavings particles and determine the optimum cement-to-particle ratio. The treatment of cement/particle ratio were 90:10; 85:15; 80:20 and 75:25. Methods of this research were two steps curing. The first step was air curing using cold press for ±4 days and continued of second step was oven curing at 80̊ C for 24 hours. The result of the research showed that cement-bonded particleboard produced density value around 0,73-1,13 g/cm3, moisture content 8,37-12,16%, water absorption on immersion 2 hours and 24 hours around 23,78-43,48% and 27,33-51,90%, thickness swelling on immersion 2 hours and 24 hours around 0,79-1,82%  and 1,39-2,89%, modulus of elasticity around 114,21-880,17  kg/cm2, modulus of rupture around 7,32-18,52 kg/cm2 and internal bond around 0,88- 1,56 kg/cm2. The effect of cement/particle ratio on the research showed that 80:20 is very good compared from 90:10; 85:15 and 75:25.Key words: cement-bonded particleboard, pencil shavings particles, cement-to-particle ratio.
Kualitas Laminasi Bambu Betung (Dendrocalamus asper) pada Berbagai Perlakuan Ukuran Sortimen dan Buku Bambu Putri Rafika Wulandari; Luthfi Hakim; Tito Sucipto
Peronema Forestry Science Journal Vol 4, No 4 (2015): Peronema Forestry Science Journal
Publisher : Program studi Kehutanan USU

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Abstract

Laminated boards made from bamboo betung (Dendrocalamus asper) with the influence of different sizes and the presence of node sortimen. The purpose of this study was to evaluate the physical and mechanical properties of laminated bamboo betung, evaluating the effect of nodes and size sortimen the physical and mechanical properties of laminated bamboo board betung and determine the best size and the existence of the book sortimen bamboo as laminate raw material. Testing the water content, water absorption, delamination and bending strength is based JAS standard SE-7 2003 on Flooring surfaces while bonding strength testing is done based on ISO standard ISO 16981-2012.  The results show the quality of bamboo betung laminate board meets the standards JAS-7-2003 SE for testing moisture content, delamination, but for testing water absorption does not fulfilling. On the mechanical properties of bamboo betung laminated board meets the standards JAS-7-2003 SE for testing bending strength and meets ISO 16981-2012 standards for surface bonding strength testing. The best treatment for laminated boards are laminated boards without involving nodes with a size of 20 cm sortimen.Keyword : Dendrocalamus asper, node, sortimen size, laminated board
KOMPETENSI SOSIAL GURU IPA DI MADRASAH IBTIDAIYAH SWASTA ANNUR ISLAMIC FULLDAY SCHOOL TAHUN AJARAN 2020-2021 Ranisa Sagita; Nazar Ikhwan; Rohanis Luthfiyyah Rahma; Luthfi Hakim
Academy of Education Journal Vol 13 No 1 (2022): Academy of Education Journal
Publisher : Fakultas Keguruan dan Ilmu Pendidikan

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (185.694 KB) | DOI: 10.47200/aoej.v13i1.990

Abstract

Social competence is the ability of teachers to communicate and interact effectively and efficiently with students, fellow teachers, parents/guardians of students and the surrounding community. A teacher must try to develop communication both in the school environment and in the community. This research uses naturalistic qualitative research, which aims to make jokes in a systematic, accurate and accurate way about the facts or encountered in the field. The result of this research is that science teachers have not fully implemented social competence indicators. The indicators that have not been fully implemented are building effective communication with parents of students, and science teachers have not communicated with their own professional community and other professions orally and in writing or in other forms
SISTEM AIR MINUM OTOMATIS PORTABLE BERBASIS SOLAR CELL Towijaya; Luthfi hakim; sukmo sudiono
Cahaya Bagaskara : Jurnal Ilmiah Teknik Elektronika Vol. 5 No. 2 (2020): Vol. 5. No. 2 - Agustus 2020
Publisher : Universitas Muhammadiyah Pekajangan Pekalongan

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Abstract

Pembuatan alat ini bertujuan untuk memberika solusi permasalahan air minum untuk memenuhi kebutuhan masyarakat yang sedang terdampak bencana alam. Karena pada saat bencana keberadaan air minum sangat terbatas dan berdasarkan pokok permasalahan tersebut penulis membuat alat pensuplai air minum otomatis portable berbasis solar cell. Alat ini berfungsi untuk mengoptimalkan pendistribusian air minum agar efisien system energi listrik yang digunakan pada alat ini menggunakan tegangan 12 volt dc dari aki sebagai penyimpanan daya . Pemanfaatan energi listrik tenaga matahari yang dirancang dengan menambahkan beberapa komponen pendukung seperti timer, solenoid valve, limith swith, relay dan pompa air dibuat menjadi sistem kran air otomatis. Sistem ini bekerja dengan dikontrol oleh timer, limit swith dan solenoid valve yang dapat mengatur jadwal buka keran air secara otomatis dan membatasi volume air yang mengalir pada kran. Metode yang dilakukan pada aplikasi ini dengan memanfaatkan system sollar cell atau tenaga matahari yang keberadaanya tidak terbatas, kemudian system ini dikendalikan oleh limit swith dan relay untuk mengatur pompa air agar dapat bekerja sesuai yang diharapkan Berdasarkan hasil penelitian diperoleh kesimpulan bahwa, solar cell 50 wp dapat mengisi aki 32 ah dengan waktu 9 jam 2 menit dan juga dengan aki tersebut dapat mengoperasikan beban secara terus menerus dengan daya 37 watt selama 8 jam 36 detik dan hasil perancangan ini didapat bahwa kran air akan terbuka pada saat diberik instruksi membuka secara otomatis, kemudian akan tertutup apabila waktu operasi timer telah habis ( 36 detik ) dan air telah mencapai batas volume yang telah ditentukan yaitu satu liter
Co-Authors Ali, Syurkarni Desi Natarina Sembiring Dodi W. Irawanto Febrina Heryani Tarigan Jendro Zalukhu Jon Herianta Ginting Marcelila Medynda Nazar Ikhwan Putri Rafika Wulandari Ranisa Sagita Rohanis Luthfiyyah Rahma Rudi Hartono sukmo sudiono Tito Sucipto Towijaya Yunus Afifuddin