bluuebunny/crossref_metadata_2025 huggingface dataset:
Perancangan Tata Letak Mesin di Workshop Permesinan MIDC Dalam Rangka Meningkatkan Produktivitas
Authors: Abdullah Hafid , Nugroho Nurkamal Hadi , Taryaman Tatang
Published: September 2018

Masalah terletak pada rendahnya produktivitas dalam penanganan jasa pelayanan order di bengkel permesinan MIDC adalah karena masih digunakannya mesin berumur tua dan konvensional. Tujuan penelitian adalah meningkatkan produktivitas melalui usulan perancangan tata letak mesin yang tepat dan pemanfaatan mesin CNC sesuai aliran proses. Untuk contoh kasus pembuatan produk bushing, diperoleh peningkatan produktivitas menjadi 2 kali lipat. Hasil penelitian menyimpulkan bahwa: (1) produktivitas produk bushing naik dari 25 unit/hari menjadi 50 unit/hari, (2) jumlah operator yang mengerjakan turun dari 6 orang menjadi 3 orang, (3) penggunaan secara optimal mesin bubut CNC dapat menghilangkan 3 tahapan proses konvensional, (4) waktu pembuatan bushing lebih cepat dari 35 menit/unit menjadi 15 menit/unit. Bahasan ini diharapkan dapat membantu MIDC ataupun pihak pengelola industri logam mesin dalam penerapan metode perancangan tata letak mesin agar perusahaannya mampu bersaing di pasar global.
Pengembangan Sumber Daya Manusia (SDM) Berpola P3JJ untuk Peningkatan Kompetensi Teknologi Pengecoran
Authors: Haddy George Z. , Abdullah Hafid , Saefudin Asep
Published: September 2018

Masalah terletak belum diaplikasikannya pengembangan sumber daya manusia (SDM) berpola Profesi dengan 3 Jalur ber-Jenjang (P3JJ), yaitu: (1) Pengoperasi, (2) Pemanfaat dan (3) Pengelola di MIDC. Tujuan aplikasi adalah untuk peningkatan kompetensi teknologi pengecoran di MIDC dan ruyukan bagi pengembangan SDM di industri pengecoran dalam negeri. Cara peningkatan melalui implementasi pemetaan SDM pengecoran, yang meliputi: (a) pohon kebisaan, (b) acuan kebisaan, (c) materi pelatihan untuk peningkatan kebisaan. Hasil implementasi dapat dijadikan bahan pertimbangan dalam memberikan program pelatihan maupun mutasi, rotasi dan promosi untuk meningkatkan produktivitas kerja. Bahasan ini diharapkan menjadi sumbangan pemikiran yang berarti bagi pengembangan usaha industri pengecoran dalam negeri di masa mendatang.
ANALISIS KEGAGALAN TABUNG GAS LPG KAPASITAS 3 KG
Authors: Tarmizi -
Published: September 2018

Penelitian ini dilakukan untuk mengetahui penyebab dari kebocoran tabung gas LPG kapasitas 3 kg yang terjadi di daerah lasan (circumferensial welding). Untuk itu dilakukan pengkajian kualitas dan performance di daerah lasan pada badan tabung secara metalurgi, dengan melakukan pengujian komposisi kimia, pengujian mekanik yaitu: uji tarik, uji bending, uji kekerasan, dan metallografi. Sifat mekanik dari tabung pada dasamya dipengaruhi oleh komposisi kimia dan struktur mikro. Dari hasil uji komposisi kimia, badan tabung mempunyai nilai CE < 0,40%, sehingga mempunyai kemampuan untuk dilas. Tetapi nilai sensitivitas retaknya (Pem) mendekati nilai kritis (2,3%) sehingga nilai kekuatan tarik dan keuletannya pada sambungan las relatif turun yang menyebabkan adanya retakan dari hasil uji bending. Perbedaan perubahan nilai kekerasan rata-rata yang sangat besar yaitu dengan adanya kenaikan antara weld metal dengan fusion line sebesar 11,60% (25,11 HV) dan terjadi penurunan antara fusion line dengan HAZ sebesar 0,56% (1,21 HV). Perbedaan yang sangat besar inilah yang memicu terjadinya retak saat pengujian bending padaface bend, dimana lokasi retakan ada di fusion line. Kebocoran yang terjadi di daerah lasan (circumferensial welding) disebabkan oleh penipisan dinding tabung akibat proses joggling sehingga pada saat pengelasan arus yang digunakan akan terlalu besar yang akan menyebabkan terjadinya cacat burn through di daerah akar las, sehingga mengubah dimensi ketebalan dinding tabung yaitu dengan adanya cacat yang menyerupai takikan. Hal ini merupakan inisiasi terjadinya retak yang merambat menembus dinding tabung sehingga terjadi kebocoran.
PENGEMBANGAN PROSES PEMBULATAN GRAFIT (NODULARISASI) MELALUI IN-MOULD PADA BESI COR BERGRAFIT BULAT
Authors: Sjaifudin Achmad
Published: September 2018

Telah dilakukan penelitian mengenai pembuatan besi cor bergrafit bulat yang proses nodularisasinya dilakukan di dalam cetakan atau yang disebut in-mould process. Paduan FeSiMg dengan kandungan 4 % Mg, dipakai sebagai agen pembulatan grafit yang diletakan di dalam cetakan. Tungku peleburnya menggunakan tungku listrik induksi tanpa inti, 3000 Hz, dengan kapasitas 15 kg besi cairo Cetakannya adalah cetakan pasir basah dengan bentuk produk cornya berupa batang silinder dengan ukuran 0 25 mm x 200 rnm, sebanyak 2 buah dalam satu cetakan. Parameter percobaan adalah dimensi ruang nodularisasi, penambahan FeSiMg, dan ukuran partikel FeSiMg. Pada percobaan awal dengan desain saluran turun yang terpisah dari ruangan nodularisasi menghasilkan besi cor vermicular. Selanjutnya dengan perubahan desain yakni saluran turunnya langsung ke ruangan nodularisasi dan dimensi ruangan diperbesar, penambahan FeSiMg sebesar 2 dan 2,5% dengan ukuran partikel 14 mesh, serta penambahan inokulan 0,2 % menghasilkan besi cor bergrafit bulat dengan matriks ferritic-pearlitic, fasa ferritnya lebih dari 90 %. Hasil pengujian mekaniknya adalah sebagai berikut: kuat tarik 450 dan 460 MPa, kuat luluh 300 dan 290 Mpa, elongasi 14 dan 16 %, kekerasan 170 dan 172 HB berturut-turut untuk penambahan 2 dan 2,5 % FeSiMg.
KARAKTERISASI MINERAL TANAH JARANG IKUTAN TIMAH DAN POTENSI PENGEMBANGAN INDUSTRI BERBASIS UNSUR TANAH JARANG
Authors: Virdhian Shinta , Afrilinda Eva
Published: September 2018

Di Indonesia, mineral tanah jarang, monasit, xenotime dan zircon diasosiasikan dengan deposit alluvial timah, uranium dan emas. Mineral tanah jarang ditemukan sebagai mineral ikutan dari proses penambangan dan ekstraksi mineral timah. Pulau Bangka dan Belitung yang terletak di antara Semenanjung Malaysia dan Sumatera bagian timur diketahui sebagai deposit timah alluvial utama di Indonesia. Penelitian ini bertujuan melakukan karakterisasi dasar mineralogi dan komposisi kimia dari mineral tanah jarang yang berasosiasi dengan bijih timah. Mineral seperti monasit dan xenotim yang merupakan mineral ikutan mengandung sedikit kandungan unsur radioaktif seperti Th dan U. Hasil pengujian semi kuantitatif dari beberapa mineral (selected minerals) menggunakan EDX menunjukkan monasit memiliki rata-rata kandungan Ce 28,2%; La 12,9%; Nd 9,7%; Pr 5,2% dan Gd 3,9%. Sedangkan xenotim mengandung unsur utama Y 29,5%; Dy 7,7% dan Gd 2,6%. Potensi pemanfaatan dan pengembangan industri berbasis tanah jarang didiskusikan dalam tulisan ini.
PENELITIAN EFISIENSI ENERGI PADA MESIN HORIZONTAL BORING & MILLING
Authors: Harbintoro Sony
Published: September 2018

Penelitian mengenai efisiensi energi pada mesin horizontal boring & milling telah dilaksanakan di workshop pemesinan Metal Industries Development Center Bandung. Efisiensi energi pada bidang manufaktur merupakan salah satu faktor penting dalam proses mendukung green industry. Penelitian ini menganalisa dampak dari retrofit sistem kendali terhadap penggunaan energi listrik pada mesin horizontal boring & milling. Metode penelitian efisiensi penggunaan daya listrik dilaksanakan sebelum dan sesudah retrofit pada sistem kendali. Pengukuran penggunaan daya listrik dilaksanakan pada saat mesin mengerjakan benda kerja dengan material yang sama. Data dari hasil pengukuran, dianalisis untuk mendapatkan besaran efisiensi energi listrik. Dari penelitian ini ditampilkan bahwa setelah dilakukan retrofit sistem kendali, dapat dicapai penurunan penggunaan energi listrik sebesar 21,5%.
PENYUSUNAN (FITTING) DATA TITIK (POINT CLOUD) DARI PROSES PEMINDAIAN (SCANNING) 3 DIMENSI PADA PRODUK CYLINDER HEAD COVER
Authors: Pujiyanto Pujiyanto , Virdhian Shinta
Published: September 2018

Mesin pemindai tiga dimensi merupakan suatu alat pemindai titik-titik pada permukaan suatu obyek benda kerja. Keluaran dari alat pemindai ini adalah data titik (point cloud) yang merupakan suatu set data titik titik dalam sistem koordinat. Data-data titik ini digunakan untuk membuat model CAD 3 dimensi. Pemodelan 3 dimensi ini dapat digunakan dalam proses manufaktur, metrologi/inspeksi, visualisasi, animasi dan lain-lain. Makalah ini bertujuan untuk menyusun data-data titik yang didapatkan dari proses pemindaian produk cylinder head cover sehingga data yang diperoleh dapat disusun mirip perwujudan produk contoh yang dipindai. Tahapan yang dilakukan adalah pemindaian 3 dimensi, perbaikan, penyusunan berkas data, analisa simpangan, dan penyatuan berkas. Dengan tahapan-tahapan itu hasil yang didapatkan diharapkan memiliki deviasi rata-rata yang optimum. Hasil analisis deviasi dari data titik-titik (point clouds) menunjukkan bahwa pemindaian berkas pada bagian permukaan luar memiliki batas deviasi rata-rata yang lebih kecil (-0.1983 ~ 0.1912) bila dibandingkan dengan pemindaian berkas pada permukaan bagian dalam dari cylinder head cover (-0.6769 ~ 0.6319).
PEMBUATAN PADUAN NdFeB UNTUK APLIKASI BAHAN BAKU MAGNET PERMANEN
Authors: Virdhian Shinta
Published: September 2018

Penggunaan magnet NdFeB menjadi semakin luas seiring dengan makin tingginya kesadaran tentang pemanasan global. Penelitian ini bertujuan untuk mengembangkan proses pembuatan paduan logam tanah jarang yang dapat digunakan sebagai bahan baku magnet permanen serta memperoleh serbuk paduan logam tanah jarang dengan sifat magnetik yang baik. Dalam penelitian ini dilakukan metode casting-powder metalurgi. Proses peleburan dengan menggunakan Argon Arc Melting Furnace dapat menghasilkan ingot yang cukup homogen, hanya saja faktor loss dari logam-logam yang dilebur harus diperhitungkan sehingga komposisi yang didapatkan sesuai dengan yang diinginkan.  Persentase fasa magnetik dari paduan yang dihasilkan sudah mendekati paduan komersial (> 80 %). Proses Annealing dapat meningkatkan jumlah fasa magnetik dalam paduan NdFeB.  Penambahan zircon dalam paduan NdFeB dapat meningkatkan kestabilan fasa Nd2Fe14B sehingga tidak diperlukan proses perlakuan panas untuk meningkatkan sifat magnetik. Sifat magnetik yang masih rendah harus ditingkatkan dengan memperbaiki kondisi operasi (vakum atau gas inert).
POTENSI BAJA KARBON RENDAH SEBAGAI ALTERNATIF BAHAN BAKU PEMBUATAN DODOS (ALAT PANEN BUAH KELAPA SAWIT )
Authors: Jaman Winda Sri
Published: September 2018

ABSTRAK         Dodos merupakan salah satu jenis alat panen tandan buah segar (TBS) kelapa sawit. Permasalahan yang ada sekarang adalah keterbatasan bahan baku pembuatan alat panen TBS kelapa sawit jenis dodos . Dodos di pasaran Indonesia selama ini masih banyak yang dimpor dari luar negeri. Penelitian pembuatan dodos dan bahan baku alternatif untuk pembuatan dodos sangat diperlukan untuk mendukung kebutuhan dalam negeri dan memajukan Indsutri Kecil Menengah (IKM) untuk membuat produk logam yang berkualitas. Metoda pembuatan dodos di Indonesia masih tradisional, dimana parameter proses tidak dapat terkontrol sehingga produk yang dihasikan memiliki kualitas yang berbeda-beda. Akibatnya, sifat mekanis dari produk lokal memiliki kekerasan yang lebih tinggi tetapi keuletanya rendah, mudah patah dan masa pakainyarendah. Untuk mengatasinya diperlukan penelitian mengenai parameter proses, supaya dihasilkan produk dengan sifat mekanis yang optimal. Penelitian ini memilih metoda karburisasi padat untuk perbaikan proses dan kualitas kekerasan produk. Parameter metoda karburisasi padat yang divariasikan adalah temperatur, waktu penahanan,  dan komposisi bahan. Kondisi optimum didapat pada kondisi temperatur 9500C, waktu penahanan 30 menit, komposisi arang 50% dan barium karbonat 50 % yang menghasilkan kekerasan 55,49±3,74  HRC.  Kondisi minimum pada kondisi temperatur 9000C, waktu penahanan 15 menit, komposisi arang batok70% dan barium karbonat 50 % didapatkan kekerasan 42,63 HRC ±5,29. Kata kunci : Dodos, Karburisasi Padat,Pengerasan Permukaan
STUDI AWAL PEMBUATAN FEEDSTOCK METAL INJECTION MOULDING MENGGUNAKAN TORQUE RHEOMETER
Authors: Afrilinda, ST., MT. Eva , VIRDHIAN SHINTA , DOLOKSARIBU MARTIN
Published: September 2018

AbstrakMeningkatnya kebutuhan masyarakat  akan alat transportasi, telekomunikasi, peralatan kesehatan, dll akan berdampak pada kemampuan industri dalam melakukan produksi secara efektif dan efisien. Metal Injection Moulding (MIM) merupakan solusi teknologi lanjut yang dapat digunakan untuk menghasilkan produk/komponen berukuran kecil, presisi dengan bentuk yang komplek dan dapat diproduksi secara massal. Persiapan Feedstock (bahan baku) berperan sangat penting dalam proses MIM, karena kualitas feedstock akan mempengaruhi kualitas produk akhir.  Feedstock adalah campuran (mixed) antara powder dan binder yang homogen dengan rasio perbandingan tertentu dan memiliki perilaku pseudo-plastik. Pada proses MIM Laju geser yang digunakan selama proses injeksi berkisar antara 100-10000 s-1 dengan viskositas maksimum sebesar 1000 Pa.s. Penelitian ini dilakukan untuk mengetahui karakterisitik rheologi feedstock melalui nilai laju geser dan viskositasnya. Hasil penelitian menunjukkan bahwa feedstock Fe2%Ni dengan binder 79%(PW) + 20%(HDPE) + 1%(SA[S1] ) dan feedstock Fe2%Ni dengan binder 79%(PW) + 20%(EVA) + 1%(SA[S2] ) memenuhi syarat rheologi sebagai feedstock Metal Injection Molding..Kata Kunci : Feedstock, binder, mixing [S1]komposisinya [S2]komposisinya
Alat Uji Ketahanan Pengunci Dan Ketahanan Tekanan Lock Up Untuk Regulator Tekanan Tinggi Tipe Pengunci Tekan
Authors: Siswanto Hendri , - Hafid
Published: September 2018

Abstrak            Perkembangan desain regulator tekanan tinggi untuk tabung baja LPG, menuntut perkembangan alat di bidang pengujian produknya. Ketepatan penentuan alat uji beserta komponen pendukungnya, sangat diperlukan agar hasil pengujian sebuah produk lebih akurat, dan presisi. Penggunaan elektropneumatik sebagai sistem penggeraknya, autocounter, dan autostop jika pengujian selesai, memberikan nilai tambah tersendiri agar pengujian sebuah produk regulator dapat lebih optimal. Hasil dari uji coba alat menunjukan hasil yang cukup bagus, alat dapat berjalan sesuai dengan kebutuhan standar regulator tekanan tinggi. Waktu total tercepat untuk pengujian ketahanan lock up dengan jumlah siklus 50.000 kali sebesar 58,88 jam. Sedangkan waktu total tercepat untuk pengujian ketahanan pengunci dengan jumlah siklus 5.000 kali sebesar 19,02 jam. Kata Kunci : Alat Uji, Lock Up, Regulator LPG, Ketahanan Pengunci
ANALISIS PERBANDINGAN PARAMETER LONG-RANGE ORDER SEBAGAI ACUAN KONTROL KUALITAS HASIL ANNEALING PASCA ECAP PADA Al-5052
Authors: Purawiardi R. Ibrahim
Published: September 2018

Telah dilakukan analisis perbandingan parameter long-range order dalam satu sudut pandang pada logam paduan Al-5052 yang diberikan perlakuan ECAP dan annealing pasca ECAP. Sudut pandang yang dipakai adalah sudut pandang tegak lurus bidang (220). Dalam analisis, bidang fundamental adalah bidang (111), sementara bidang superlattice diasumsikan bidang (220). Terdapat 4 sampel uji Al-5052 yang digunakan. Keempat sampel diberikan perlakuan ECAP rute Bc sebanyak 4 pass. Kemudian, 3 dari 4 sampel diberikan perlakuan annealing pasca ECAP dengan variasi temperatur annealing 100 oC, 200 oC, dan 300 oC, sementara satu sampel tersisa sebagai kontrol pembanding. Karakterisasi dilakukan dengan analisis x-ray diffraction. Hasil analisis menunjukkan nilai parameter order sampel tanpa annealing, sampel dengan temperatur annealing 100 oC, sampel dengan temperatur annealing 200 oC, dan sampel dengan temperatur annealing 300 oC secara berturut-turut adalah 0.54526, 0.693152, 0.92553, dan 1.183165. Dengan demikian, terjadi perubahan kondisi dari kondisi lebih disordered menjadi lebih ordered akibat perlakuan annealing pasca ECAP. Sementara itu, kondisi fully ordered diprediksi terjadi saat penerapan temperatur annealing 226.065704 oC. Dari studi ini dapat disimpulkan bahwa metode perbandingan parameter order ini dapat digunakan sebagai acuan kontrol kualitas logam paduan Al-5052 setelah proses annealing pasca ECAP. Namun, analisis ini tidak direkomendasikan untuk menentukan nilai mutlak parameter order, namun hanya direkomendasikan untuk dibandingkan antar sampel satu sama lain.
RANCANG BANGUN TIMBANGAN LOAD CELL TIPE S
Authors: Rumbara Robby Debriand
Published: September 2018

Timbangan dirancang dengan men-scale down dari timbangan kapasitas yang lebih besar. Tipe Load Cell ditentukan dan beban serta sensitivitas dihitung. Load Cell tipe S dimodelkan dengan perangkat lunak. Load Cell tipe S dimanufaktur dengan mesin CNC dan dibuat rangkaian elektronik. Pengukuran dilakukan pada dua titik: tanpa penguat dan dengan penguat. Pengukuran menghasilakan grafik dengan persamaan y = 0.0003x + 0.0031 (tanpa penguat) dan y = 0.061x + 0.191 (dengan penguat). Berat minimal yang dapat diukur oleh timbangan sekitar 1000~30.000 kg.
PENGARUH MODEL PEMBELAJARAN INKUIRI TERHADAP KARAKTER KREATIF SISWA KELAS 5 PADA MATA PELAJARAN IPA DI SDIT AL-MADINAH CIBINONG
Authors: Maryati Maryati , Triwoelandari Retno , Hakiem Hilman
Published: September 2018

The aim of this research is to know the process of applying inquiry model to the crative character of 5th grade students in science subjects in SDIT Al-Madinah Cibinong, and to know the influence of inquiry learning model on the creative character of 5th grade students in science subjects in SDIT Al-Madinah Cibinong. The approach used in this study is quantitative research with the type of quasi-experimental research, in this study the selection of samples on experimental quasi type Non Equivalent Control Group Design is not done random sample selection but deliberately selected by the researchers with each sample experiment class 21 Students and control class of 21 students. The instruments used in this research are: test, observation, questionnaire and documentation. The process of applying inquiry learning model in science subjects through six stages: Presenting questions or problems, Making hypotheses, Designing experiments, Conducting experiments to obtain information, Collecting data and analyzing data, and Making conclusions. Based on the research that has been done, the average post-test of the experimental class is 77.61 and the average post-test of the control class is 64.28 so that it is obtained -t arithmetic> -t table (-11.004> -2.086), it can It is concluded that there is a significant influence of the use of inquiry learning model on student learning outcomes. Observational data resulted in average after applying experimental class learning 92,14, and average after applying of control class study 73,57 so that obtained-t arithmetic> -t table (-20,254> -2,086), hence can be concluded that there is A significant influence of the use of inquiry learning model to foster the creative character of the students. In addition the results of the experimental class questionnaire obtained an average of 32.38 and control classes 31.43 the number of scores in the range 30-36 that students in the experimental class and control classes have a high creative value in carrying out its duties. So it can be concluded that the influence of inquiry learning model to the creative character of students. So the application of inquiry learning model can influence the students' creative character in science subjects are said to be effective and there are significant changes or improvements. This inquiry learning model can be an alternative learning model that can be applied in the learning process.
PENGARUH MODEL COOPERATIVE LEARNING TIPE EXAMPLE NON-EXAMPLE TERHADAP HASIL BELAJAR SISWA PADA MATA PELAJARAN IPA
Authors: Aisah Siti , Asmahasanah Salati
Published: September 2018

This study aims to find out the learning outcomes of students applying Cooperative Learning model type Example Non Example and using only conventional learning in science subjects class V in MI Tarbiyatusshibyan Bogor, and know how the influence of the implementation of Cooperative Learning model type Example Non Example against science subjects in class V MI Tarbiyatusshibyan Bogor. This research is quantitative descriptive with experimental design "Qusi Experiment". The population in this study is all students of class V MI Tarbiyatusshibyan Bogor with the number of 40 students, this study sample is a class A student with the number of students 20 and B with the number of students 20. Data collected through tests, namely pre-test and post-test in the class control and experiment with multiple choice questions. The results obtained from this research that the implementation of cooperative learning model type examples nin examples significantly influence the results of learning ipa. That the value of test result t that is in the experimental class obtained value -t arithmetic> -t table (-8.393> -2.090), then Ha accepted and Ho rejected. while in the control class obtained t arithmetic> -t table (-7.054> -2.090), then Ha accepted and Ho rejected. So it can be concluded that the application of learning models examples non examples have an influence on student learning outcomes.
Evaluation of arsen in surface water and groundwater layers in the Cat Tien district of the Lam Dong province
Authors: Nguyen Trung Dinh , Nguyen Thuan Duc
Published: September 2018

Evaluation of arsenic pollution in surface water and groundwarter layers in the Cát Tiên district of the Lam Dong province has been carried out during the period of 2013–2015. Arsenic concentrations of 37 samples of surface water and dug well water ranged from 0 to 5 ppb. 9/29 water samples drilling wells of the Quaternary groundwater layer had arsenic concentrations higher than those of the standard QCVN01:2009/BYT. The arsenic concentration of samples collected from the Cat Tien commune (CT-TT 04) and the Gia Vien commune (CT-GV 03) was about 10 times higher than that of the standard QCVN 01:2009/BYT. Especially, the arsenic concentration of the drilling well from Tu Nghia communes (CT-TN 04) was about 45 times higher than the standard QCVN 01:2009/BYT. Drilling wells with arsenic pollution had the Eh range from -1.4 mV to -186 mV. The concentrations of arsenic and ammonium of drilling wells in Gia Vien and Cat Tien commune were high. The concentrations of As3+and Fe2+ were higher than those of As5+ and Fe3+, respectively.
Biological activities and micropropagation of non-vascular plants from Bidoup-Nui Ba National Park, Lam Dong
Authors: Quach Phuong Ngo Diem , Do Tran Ngoc Bao , Tra Phuong Dong , Luong Tam Thien , Tran Thu Nguyen Anh , Tran Thuoc Linh
Published: September 2018

At the present time, non-vascular plants (bryophytes) are less studied, especially in Vietnam. Therefore, this research focuses on studying biological activities of some bryophytes species collected in Bidoup–Nui Ba National Park, such as antioxidative, antibacterial activity, acetylcholinesterase inhibitory activity and quantitative analysis of the major secondary metabolites. Moreover, one of the most potential species was micropropagated in vitro in order to get the initiative pharmaceutical materials. Among the six bryophyte species collected in Bidoup–Nui Ba National Park, three of them are mosses (Pyrrhobryum spiniforme, Bryum argenteum and Campylopus umbellatus) and three of them are liverworts (Lepidozia fauriana, Plagiochila trabeculata and Schistochila blumei). Our results showed that L. fauriana had the highest antioxidative activity and acetylcholinesterase inhibitory activity (IC50 = 6.617 ± 0.080 mg/mL), S. blumei had the potent antibacterial activity. In vitro propagation results showed that silver moss could be micropropagated using spores in MS medium supplemented with 1 mg/L 2,4-D and 2 mg/L kinetin.
Evaluating the wound healing ability of Melicope pteleifolia (Champ. Ex Benth.) T.g. Hartley
Authors: Nguyen Nhan Thi Thanh , Nguyen Can Minh , Tran Thuoc Linh , Dang Thao Thi Phuong
Published: September 2018

Melicope pteleifolia (Champ. ex benth.) T.g. Hartley, a folk medicinal plant, is used by ethnic minorities in Bidoup–Nui Ba National Park, Lam Dong Province, Vietnam to treat effectively wound, inflammation and skin ulcer. To scientifically prove the claimed utilization and understand the mechanism of action of the plant, the in vitro and in vivo healing properties of the extract and fractions of the plant were investigated. The ethanol 70 % extract (50 – 400 mg/mL), aqueous (200 mg/mL), ethyl acetate (100 mg/mL) and petroleum ether (50 mg/mL) fractions were used to evaluate the antibacterial activities by using agar diffusion method. The healing properties were in vitro investigated through fibroblasts and keratinocytes proliferation and migration (7.8 g/mL to 250 g/mL in accordance with each extract and fraction). Besides, the macrophage-induced inhibition of the nitric oxide (NO) production was examined (15.6 – 62.5 g/mL). In addition, the excision wound model was used to test the wound healing activity on mice model. We found that the ethanol extract and the ethyl acetate fraction showed potent activity against Staphylococcus aureus, Enterococcus feacalis and Pseudomonas aeruginosa. The extract and fractions stimulated fibroblasts and keratinocytes proliferation in a concentration-dependent way. They also inhibited macrophage produce NO. In addition, mice treated by the extract formed scabs on wound excision of mice model faster than the control group. The wound healing efficiency seems to involve antibacterial, stimulating fibroblasts and keratinocytes proliferation, inhibition of macrophages produce NO.
Isolation and identification of Agrobacterium rhizogenes inducing hairy roots of Catharanthus roseus in vivo
Authors: Nguyen Nhut Nhu , Bui Le Van
Published: September 2018

Agrobacterium rhizogenes is a common tool for transforming foreign genes into plant cell and inducing hairy root formation. A total of 274 colonies of Agrobacterium species was isolated on selective MG-Te medium from 235 samples of rhizophere soils. There were only thirteen colonies belonged to A. rhizogenes being able to efficiently induce the hairy root formation of Catharanthus roseus in vivo based on the morphological, biochemical, and pathogenicity tests. These thirteen colonies were identified as A. rhizogenes based on 16S rRNA sequence and possessing rolABC genes. The results indicated A. rhizogenes was universal in rhizophere soil in Vietnam and riched transgenic tools for researching C. roseus hairy roots in the future.
Purification of p24 protein expressed in Bacillus subtilis and evaluation of its immunogenicity in mice
Authors: Truong Tuom Thi Tinh , Phan Trang Thi Phuong , Nguyen Hoang Duc
Published: September 2018

p24 protein is a component of the HIV particle capsid. It plays an essential role in HIV to infect into the host cell and in the cycle life of virus. Therefore, this protein can be used in the orientative study “to create and produce HIV’s vaccine”. This study created the new Bacillus subtilis strain which expressed p24 protein. B. subtilis a safety and non-toxic bacteria strain for humans and animals, has system expression to allow over expression recombinant protein up to 10-30 % of total proteins. Plasmid pHT1537 was cloned successfully, containing lysSN-6his-gagp24 gene to encode p24 protein fused with LysSN protein and to allow the expression of p24 protein in B. subtilis by IPTG inducer. The target protein in the cell was cheked by SDS-PAGE. The p24 fused protein was parified from His Trap column which contained Ni2+. Evaluation of the ability to produce antibody against p24 protein in mice by ELISA and Western blot was caried out.
Treatment of catfish processing wastewater by the combination of anaerobic and aerobic package cage rotating biological contactors
Authors: Le Viet Hoang , Ngo Duc Hue , Nguyen Thuan Huu , Nguyen Ngan Vo Chau
Published: September 2018

The study aimed to diversify the treatment technology of catfish processing wastewater. The experiments were implemented on lab-scale package cage rotating biological contactors with the first stage in anaerobic condition and the second stage in the aerobic condition, using PVC flexible conduit medium. The selected hydraulic retention time of anaerobic stage was 12 hours, and that of aerobic rotating package cage biological contactor was 4 hour 12 minutes. The results showed that almost monitoring parameters (pH, SS, DO, COD, BOD5, TKN, Ptotal) met the national standards of QCVN 11-MT:2015/BTNMT (column A), except +NH4 only reached the QCVN 11-MT:2015/BTNMT (column B). The results confirmed that combining both anaerobic and aerobic package cage rotating biological contactors with PVC flexible conduict medium could apply to treat catfish processing wastewater.
Aminolysis of poly(ethylene terephthalate) waste bottle with tetra/hexamethylene diamine and characterization of alpha, ohmega-diamine products
Authors: Hoang Cuong Ngoc , Dang Yen Hoang
Published: September 2018

The aminolysis of poly(ethylene terephthalate) (PET) waste bottle with excess amount of aliphatic diamines, such as tetramethylenediamine (TMDA) and hexamethylenediamine (HMDA) without catalyst has been carried out. Each trimers and pentamers in the obtained products were isolated and characterized by FTIR, NMR, HPLC methods. Although an excess of diamine was employed, longer blocks of oligomers were still formed as minor products.
In vitro propagation of Xao tam phan (Paramignya trimera (Oliv.) Guill.)
Authors: Tran Hieu Trung , Huynh Chung Van , Bui Hue Thi Linh , Luong Ngan Thi My , Bui Anh Lan , Bui Le Van
Published: September 2018

Paramignya trimera (Oliv.) Guill., a woody climber commonly known as "Xao tam phan", has been used in Vietnamese folk for the treatment of numerous cancers. Due to word of mouth about the anticancer properties of this plant, its stems and roots have been overexploited leading to the serious decline of this species in Phu Yen, Khanh Hoa and Ninh Thuan provinces. The aim of the study was to establish an in vitro propagation protocol for the conservation of P. trimera. In this research shoot clusters (5–8 shoots/cluster) were regenerated from axillary bud explants of 1–3 year-old trees after 3 months of cultures on the WPM (woody plant medium) supplemented with STS 3 and BA 5–7 mg/L. STS (silver thiosulfate) was used to prevent the leaf abscission. These shoot clusters grew slowly and reached 1–3 cm in heights after 4 months of the cultures. These shoot clusters did not form any roots after 2 months of culture on the rooting media with IBA and/or NAA 1–5 mg/L. However, there was 51 % of the treated shoot clusters acclimatized and produced new stem and leaves after 2 months growing in greenhouse. WPM supplemented with STS 3, BA 5 and IBA 5 mg/L showed the best response for callus induction in leaf explants after 3 months of cultures. Among the callus types, the milky white compact calli were induced at the cut surface of leaf explants after 3 months of the cultures and became the compact and nodulated calli within 4 weeks later.
Nymphoides aurantiaca (Dalzell) Kuntze, a new record of family Menyanthaceae for the flora of Vietnam
Authors: Nguyen Nga Phi , Tran Triet , Nguyen Thuy Thi Thu
Published: September 2018

The newly recorded species, Nymphoides aurantiaca (Dalzell) Kuntze belonging to family Menyanthaceae, was discovered at some wetland areas in Lò Gò–Xa Mát National Park (Tân Biên, Tây Ninh). This species was found for the first time in 2003 during a research on wetland biodiversity and conservation funded by Tây Ninh Province’s Department of Science and Technology. Special morphological characteristics of the species include floating leaf blades, deeply cordate at base; flowers usually two per node; five dark yellow corollas with fimbriately toothed margins. This aquatic species inhabits standing water bodies such as shallow ponds, flooded lowlands with water depth of 20-40 cm, low turbidity and slightly acidic with pH values ranging from 5.4 to 6.0. The phylogenetic affinity between N. aurantiaca and other Nymphoides species was established based on matK sequence of chloroplast DNA.
Study of the nuclear medium by 12C + 12C elastic scattering analysis at low energy region
Authors: Le Chien Hoang , Do Cuong Cong , Nguyen Phuc Hoang , Dao Khoa Tien
Published: September 2018

The nuclear medium is investigated by studying the 12C + 12C elastic scattering at the low energies in the framework of optical model (OM) potential. Both frozen and adiabatic density approximations are used for the description of the nuclear medium during the colliding process. In the OM calculation, the double folding procedure using the realistic CDM3Y3 effective nucleon-nucleon (NN) interactions and the wave functions of colliding nuclei is employed to describe the nucleus-nucleus potential at low energy region below 10 MeV per nucleon. The obtained results from the elastic scattering analyses show that the adiabatic density approximation is more reasonable than the frozen density approximation to describe the overlapping density (the so-called nuclear medium) for the 12C + 12C system at low energy region.
Assessment of the adaptive capacity to the climate change of rural fresh water and sanitation – A case study in Can Gio district
Authors: Le Tuan Ngoc
Published: September 2018

This work aimed at calculating and assessing the adaptive capacity (AC) to the climate change (CC) of the rural fresh water and sanitation (RFWS), a case study in Can Gio for the period of 2014–2025. By index, survey, and professional adjustment methods, the AC index was considered and evaluated via two main indicator groups: infrastructures (6 indicators) and humans (13 indicators). Results show that Binh Khanh has the highest AC index, 57 points–medium high level, with strengths in infrastructure, especially in the human indicator group. The management of local government, transportation system, or social services are the highlights here. AC index in Can Thanh is runner-up with 55 points - medium high level. However, different from Binh Khanh, strengths in Can Thanh come from infrastructure group. AC indices of Ly Nhon, Tam Thon Hiep, Thanh An, Long Hoa, and An Thoi Dong are at medium low level, ranging from 43–49. By 2020, 2025, AC index increase following the increase in water supply and drainage network, social and economic development plan. This work also review strengths and weaknesses in CC adaptive capacity of RFWS in the local, supplying the basis for establishing solutions to mitigate CC impacts.
Effect of growth factors on the production of biomass of the hairy root of Urena lobata
Authors: Cao Dai Minh , Vu Phuong Thi Bach , Quach Phuong Ngo Diem
Published: September 2018

Urena lobata, one of the traditional medicine, is used to treat inflammation, arthritis or improve lipid profiles in liver and blood. There also has been a lot of studies in the world about its potential biological activities. Interestingly, root extract usually has higher biological activities than the whole plant or other parts. Therefore, applying several modern biotechnology techniques could help to initially obtain this potential resource. In this research, we demonstrated the application of some growth factors which can increase the biomass of hairy root such as: inoculum density, light condition, medium and proportion of marco-nutrient. The results showed that when hairy roots were cultured at the inoculum density of 10 g/L FW, under illumination at 3000 lux, WPM medium supplemented 4 % sucrose were more suitable for the growth of hairy root. At the same time, when all these factors were put fogther the haing root grouthr was improved. The fresh weight (FW) and dry weight (DW) increased 2.01-fold and 1.94-fold, respectively.
Isolation and selection of Lactobacillus spp. antagonistic to Vibrio parahaemolyticus causing the (Early Mortality Syndrome) shrimp disease in Soc Trang province
Authors: Do Dung Thi Thanh , Vo Quang Dinh , Phan Trang Thi Phuong
Published: September 2018

Early mortality syndrome (EMS) caused by pathogenic Vibrio parahaemolyticus is one of the most major factors affecting the development of aquaculture. Using the antagonism of probiotics against pathogens is an alternative strategy to antibiotics and has lots of potential to control pathogenic bacteria. In this study, we isolated and screened total of 8 Lactobacillus strains from 30 mud, water and shrimp samples at shrimp ponds in Soc Trang province. All of them were be able resistant with Vibrio parahaemolyticus strains causing the EMS shrimp disease in vitro. In which, TA7L1 strain showed the strongest resistance and was identified as Lactobacillus plantarum by analysing 16S rDNA sequence and MALDI-TOF. TA7L1 strain was determined safety and has potential application in the production of biological products to prevent EMS shrimp disease.
Removal of copper and zinc from plating wastewater by megnatic separation method
Authors: Le Thuy Thi Xuan , Le Thuy Thi Xuan , Ho Quyen Hong , Nguyen Mai Thi Sao
Published: September 2018

Copper (Cu) and Zinc (Zn) are two popular heavy metals using in the mining operation, metallurgic industry, metal plating facilities, etc., and their effecs on the environment and human health are quite seriously. Application of a new adsorbent γ-PGM (-poly glutamic acid coated magnetite) is one of the new methods to separate toxic heavy metals Cu and Zn from water and wastewater. This study showed that 0.2 g/L γ-PGM at pH 6 with the shaking speed 200 rpm in 10 minutes were the best conditions for removal of Cu and Zn. The efficient removal of Cu and Zn was 99.91 % and 99.75 %, respectively. Besides, regeneration the ability of γ-PGM particles reached to 12 times while using hydrochloric acid HCl 0.1 N for 1 hour for desorption of the materials which is the best optimal conditions for separating Cu2 + and Zn2 + ions from the surface of γ-PGM particles. The results indicated that γ-PGM was the potential material for the application to the heavy metals removal in water and wastewater with various outstanding characteristics.
Use of microsatellite markers in differentiating catfish hybrids (Clarias macrocephalus x C. larias gariepinus) from their parental species
Authors: Duong Yen Thuy
Published: September 2018

This study aimed to develop microsatellite markers that can be used to differentiate catfish hybrids (bighead catfish Clarias macrocephalus x African catfish C. larias gariepinus) from their parental species. Microsatellite primers developed from previous studies were screened and optimized. Six microsatellite markers were selected to amplify samples of bighead catfish (n = 37), African catfish (n = 29), and the hybrids (n = 30). Results show that 4 of 6 loci differ in allele numbers and sizes between the bighead and African catfish. In the other two loci, these two species share one allele that overlaps at a portion of the size range with different allele frequencies. Hybrids’ genotypes are intermediate between those of the parental species. The genetic divergence between bighead and African catfish is high with Fst = 0.59 and Rst = 0.95. Therefore, these 6 microsatellites were applied to successfully distinguish hybrids from their parental species with high accuracy.
An efficient floating-point FFT twiddle factor implementation based on adaptive angle recoding CORDIC algorithm
Authors: Vo Thao Thi Phuong , Truong Quynh Thi Nhu , Hoang Thuc Trong , Le Hung Duc
Published: September 2018

In this paper, a single-precision floating-point FFT twiddle factor (TF) implementation is proposed. The architecture is based on the Adaptive Angle Recoding CORDIC (AARC) algorithm. The TF design was built and verified on Altera Stratix IV FPGA chip and 65nm SOTB synthesis. The FPGA implementation had 103.9 MHz maximum frequency, throughput result of 16.966 Mega-Sample per second (MSps), and resources utilization of 7.747 ALUTs and 625 registers. On the other hand, the SOTB synthesis has 16.858 standard cells on an area of 298x291 μm2, 166 MHz maximum frequency, and the speed of 27.107 MSps. The accuracy results were 1.133E-10 Mean-Square-Error (MSE) and about 26 part-per-million (ppm) maximum error.
Assessing the thermal comfort in non-air conditioned classrooms in Ho Chi Minh City
Authors: Nguyen Nam Thi Que , Nguyen Nam Thi Que , Tran Thanh Cong
Published: September 2018

Thermal comfort is a parameter to assess environmental indoor quality which affects especially performance of students. A cross-sectional study was conducted in classrooms at a university campus in Ho Chi Minh City to assess the thermal condition during the class time. Microclimate parameters were measured at the same time when students answered the survey on their thermal sensation and acceptability of the indoor climate. Objective data analysis from adaptive PMV model for non-air-conditioned buildings revealed that none of classes had the thermal condition were in the comfort zone of TCVN 7438:2004, coinciding with the subjective result from the surveys. The research showed that 72 percent of the 472 students did not accept the thermal environment and 91.3 percent of students preferred cooler. The suggested neutral temperature was 29.4 oC, the derived from the linear regression between adaptive Predicted Mean Vote (aPMV) and operative temperature (To).
Calculation of the shielding safety of Computed Tomography scanner room by using MCNP5 code
Authors: Tran Khanh Ai , Cao Thong Minh , Dang Phuong Nguyen , Truong Loan Thi Hong , Mai Nhon Van
Published: September 2018

Shielding design of Computed Tomography scanner room is a vital work to ensure radiation safety for medical physicists and public. In this paper, we measured CTDI (CT Dose Index) and determined the normalization factor between Monte Carlo simulation and experiment values of absorbed dose. Then, the absorbed dose distribution inside and outside the CT scanner room were surveyed for the variation of the room size. In addition, the influence of photons scattered from the shielding material to patients while shrinking the sizes of the room is also studied in this work.
Controlling the morphology of polycaprolactone microparticles produced by electrospraying
Authors: Nguyen Linh Vu Viet , Huynh Phu Dai
Published: September 2018

Electrospraying is an effective method to produce polycaprolactone microparticles for drug or protein carrier application. In this study, some factors which influenced the morphology of polycaprolactone (PCL) particles were investigated by Scanning Electron Microscopy (SEM), such as polymer concentration, solvent and distance from tip to the collector. The SEM micrographs indicated that the low concentration (1 %) of PCL solution created in wrinkled and hollow semi-spheres while wrinkled spheres were formed by using higher polymer concentration (4 %). The spherical morphology was obtained when the polymer concentration was high enough (4 %) to create significant chain entanglements. In addition, chloroform and dichloromethane were good solvents to fabricate electrosprayed microspheres. Solvent mixtures such as acetone and chloroform or Dimethylformamide (DMF) and chloroform were unsuitable for electrosprayed particles since they caused unstable and heterogeneous shape. This research demonstrated that the morphology of microparticles was controlled by adjusting parameters of electrospraying to have a homogeneous and stable morphology.
Degradation of recalcitrant organic polluants in seafood wastewater by modified TiO2 photocatalysts
Authors: Luu Loc Cam , Ho Da Linh , Hoang Phu Chi , Nguyen Tri , Nguyen Van Thi Thuy , Hoang Cuong Tien , Ha Anh Cam
Published: September 2018

In seafood processing plants, industrial waste water discharge reached virtually the level B (QCVN 11-MT:2015/BTNMT) after using mechanical, physicochemical and biological wastewater treatment methods. However, their COD values (COD = 20-120 mg/L) were not qualified for allowable concentration of discharge requirement - level A (COD ≤ 75 mg/L) in many cases. In this paper, bio-treated seafood waster water was continually treated by TiO2 photocatalyst modified by doping Fe and N to degrade recalcitrant organic pollutants to obtain the A level water which can be resused. TiO2 modified by doping Fe and N were prepared and investigated the physico-chemicalproperties. The results showed that modified TiO2 had a lower band gap and more photoactivity than pure TiO2. Beside that, at the reaction conditions: reaction temperature 25 oC, dissolved oxygen concentration 7.6 mg/L and pH = 7, the optimal concentration of catalysts was determined (1.25 g/L). After 12 hours of treatment, COD removal efficiency on TiO2-Fe and TiO2-N catalysts attained 41.1 % and 64.3 %, respectively, and their COD values reached 49.3 and 29.9 mg/L, correspondingly. After treatment, the quality of waste water discharge met the level A (QCVN 11-MT:2015/BTNMT) and became a safety source for reusing (QCVN 08-MT:2015/BTNMT). In addition, the relationship between the characterization of modifed TiO2 and their activity was characterized.
Flash floods potential area mapping at Huong Khe district, Ha Tinh prov
Authors: Nguyen Duyen Thi My , Ha Hai Quang
Published: September 2018

Ha Tinh is one of the provinces most affected by natural hazards, especially flash floods. Sloping hilly terrain conditions, reduced covering density of forest and unfavorable weather conditions are potential hazards to flash floods. Flash floods potential area mapping at Huong Khe district, Ha Tinh province was carried out using Remote Sensing and GIS technologies. Factors causing flash floods was indentified and classified basing n their afecting level. Component maps of flash flood–causing factors were overlayed. Factors causing flash floods as noted by Greg Smith included: slope, soil type, forms of using land, covering density of forest. Potential areas of flash floods and the potential level of each part were indentified. The resulted maps can be used for forecasting risk regions of flash floods at the district.
Growth and characterization of KDP single crystals by Sankaranarayanan-Ramasamy (SR) method
Authors: Phan Vinh Trung , Le Anh Thi Quynh , Huynh Dat Thanh
Published: September 2018

Pure KDP single crystals were studied extensively since the 1930s because they could be grown easily to reach a large size, of their low cost and piezoelectric property. Since then, many applications of the KDP crystal have been developed such as the electro-optic modulation, the optical switch (Q-Switch) and the frequency of laser converter through the second-, thirdorder nonlinear effects. In response to these applications, the high-quality KDP single crystals are required. The common method of growing KDP crystal is the temperature lowering, in which a KDP seed is placed in a supersaturated solution. The disadvantage of this method is the spontaneous appearance of crystalline clusters at the bottom of the container which retard the growth of the main crystal. Since the 2010s, Sankaranarayanan and Ramasamy have proposed a new method of growing crystal by designing the Y-shaped solution container. In this study, the KDP single crystals were grown by the SR method. These crystals have better quality, fewer defects, higher hardness and density, and especially material saving compared to the ones prepared by the traditional methods.
Preparation of magnetic nanocomposite materials based on chitosan/Fe3O4
Authors: Nguyen Ngoc Bao , Hoang Quy Thi Dong , Nguyen Uyen Thai Ngoc
Published: September 2018

Magnetic nanocomposite materials based on chitosan/ Fe3O4 were prepared by two different methods. The magnetic iron oxide nanoparticles were synthesized by co-precipitation method of solution containing Fe2+ and Fe3+ ions in NH4OH solution. The reaction temperature was kept at 70 °C for 2 hours under nitrogen atmosphere. The dispersion of Fe3O4 was subsequently dropped in chitosan solution 1 % w/v and stirred for one hour to afford magnetic nanocomposite (CS-ex). The magnetic nanocomposite was also synthesized by simple, one-pot in-situ co-precipitation method (CS-in). In this procedure, the ferrous and ferric salt were dissolved directly in chitosan solution and followed by the co-precipitation in NH4OH solution at 70 °C in nitrogen atmosphere. The samples were collected by a magnet and washed with deionized water and dried in vacuum at 50 °C. The results showed that the magnetic nanocomposite synthesized by in-situ coprecipitation exhibited the advantages in comparison with the CS-ex. CS-in contained 41 % of chitosan and had the nanosized scale of 11– 15 nm, saturation magnetization of 41,82 emu/g and was thermally stable than CS-ex.