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Widyariset

widyariset
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Published by Lembaga Ilmu Pengetahuan Indonesia

ISSN : 14117932 EISSN : 24610976 DOI : -

Core Subject : Engineering,

Engineering

Widyariset is a scientific journal which publishes the results of research and development, assessment and systematic thinking about science and technology. The writers of the scientific papers in this journal come from researchers/researcher candidates from various institutions' research and development (R&D), and universities. Widyariset is published regularly three times a year: in April for the issue of Social Sciences and Humanities (IPSK), in August for the issue of Natural Sciences (IPA) and in December for the issue of Engineering Sciences (IPT).

Arjuna Subject : -

Articles 485 Documents

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WATER MASS DYNAMICS IN AMBON BAY Frilla Renty Tama Saputra; Yohanis Dominggus Lekalette
Widyariset Vol 2, No 2 (2016): Widyariset
Publisher : Pusbindiklat - LIPI

Ambon Bay has a unique characterictic with its semi enclosed water inner bay. The aim of this research is to study the dynamics of water mass in Ambon Bay through the observation of vertical and horizontal distribution of temperature and salinity. The observation was conducted in 18 different stations throughout 2015 during Northwest Monsoon (February), Transition I (April), Southeast Monsoon (August), and Transition II (November). The result shows that the dynamics of water masses in Ambon Bay is strongly influenced by the monsoon. During the Northwest Monsoon, the temperature is higher than the other season and mixing phenomenon occurs, which is caused by heat diffusion from the surface. In the Transition I, water column stratification tends to occur caused by its mixing with fresh water. In Southeast Monsoon, the temperature in Ambon Bay is lower than the other season and flushing phenomenon occurs in Inner Ambon Bay which is caused by high density water mass flow from Banda Sea to Inner Ambon Bay. Entering the Transition II, the temperature are getting warmer again and forming a stratification which is caused by heat diffusion from the surface. The salinity profile in Ambon Bay shows the similar characteristic with temperature in every season. The salinity in Inner Bay is lower than the Outer Bay due to its mixing with fresh water.

THE EFFECT OF SURFACE ROUGHNESS AND STIRRING SPEED ON THE COATING CHARACTERISTICS OF MARTENSITIC ELECTROLESS Ni-P Rafi Dwi R; Arini Nikitasari; Sunardi Sunardi; Efendi Mabruri
Widyariset Vol 4, No 1 (2018): Widyariset
Publisher : Pusbindiklat - LIPI

Coating process of martensitic stainless steel 420 (SS 420) as the base material component of the steam turbine blade component uses an Electroless Ni-P coating process. This process is one of the solution coatingsthat applied to stainless steel as a substrate to improve corrosion resistance.The goal of this research is to get an idea and information about the effect of surface roughness and stirring speed on the characteristics of Electroless Ni-P layer. Experimental parameters in this research were variations of 0.044 μm, 0.056 μm, 0.101 μm, and 0.164 μm surface roughness and variations of 4.9 rpm, 11.3 rpm, and 21.3 rpm stirring speed. Results showed that the surface roughness and low stiring speed causes the grain distribution becomes more uniform, whichis shown by Scanning Electron Microscopy (SEM) examination. Adhesion layer also increases along with increasing levels of surface roughness. The highest value of adhesion was 1.9 MPa at 0.164 μm and the lowest value of adhesion was 0.8 MPa at 0,044 μm.

Kumpulan Abstrak Bahasa Inggris Abstrak Inggris
Widyariset Vol 2, No 1 (2016): Widyariset
Publisher : Pusbindiklat - LIPI

THERMOMECHANICAL TREATMENT PROCESS OF α/βTi-6Al-6Mo ALLOY AS NEW ALTERNATIVE MATERIALS FOR BIOMEDICAL APPLICATION Cahya Sutowo; Fendy Rokhmanto; Galih Senopati
Widyariset Vol 3, No 1 (2017): Widyariset
Publisher : Pusbindiklat - LIPI

Telah dilakukan proses pengecoran paduan Ti-6Al-6Mo menggunakan arc remelting furnace dan dilanjutkan dengan proses perlakuan termomekanik berupa homogenisasi dan pengerolan panas pada temperatur 900, 1000, dan 1100 °C. Pelat Ti-6Al-6Mo hasil pengerolan panas dikarakterisasi menggunakan mikroskop optik dan mikroskop elektron untuk mengidentifikasi struktur yang terbentuk, analisa pola difraksi sinar-x dilakukan untuk mengidentifikasi fasa yang terbentuk, dan uji keras dengan metode rockwell dilakukan untuk mengetahui harga kekerasan pelat Ti-6Al-6Mo. Struktur mikro hasil pengerolan berupa struktur titanium α dan tititanium β terdeformasi. Fasa titanium α dan titanium β juga teridentifikasi pada grafik pola difraksi sinar-x. Hasil pengujian kekerasan menunjukkan kekerasan tertinggi dicapai pada pengerolan pada temperatur 1100 °C.

COMPARATIVE STUDY OF CORROSION INHIBITORS FOR REBAR STEELS IN SIMULATED PORE SOLUTION CONTAINING SEAWATER AND CARBONATES Arini Nikitasari; Faty Alvina; Efendi Mabruri
Widyariset Vol 2, No 1 (2016): Widyariset
Publisher : Pusbindiklat - LIPI

The performances of sodium nitrite and dimethylethanolamine (DMEA) inhibitors have been compared in mitigating corrosion of rebar steels in simulated pore solution containing sea water and carbonates. The simulated solution was prepared by dissolving saturation amounts of alkali hydroxides and sulphates in sea water and adding carbonates subsequently. The inhibitor of sodium nitrite and DMEA with various concentration was then added to the respective simulated solution. The corrugated rebar steels were immersed in the solutions and electrochemical corrosion was measured using potentiodynamic polarization method. The experimental results showed that sodium nitrite exhibited more effective performance compared to DMEA in mitigating rebar steel corrosion in sea water and carbonated media. The lowest steel corrosion rate of 0.27 M Sodium nitrite with 0.3 M concentration decreased corrosion rate of the steel to 0.27 M, the lowest values of the measured corrosion rates this work.

Kumpulan Abstrak Indonesia Indonesia Indonesia
Widyariset Vol 3, No 1 (2017): Widyariset
Publisher : Pusbindiklat - LIPI

PEDOTRANSFER FUNCTIONS FOR DIGITAL SOIL MAPPING IN TROPICAL REGION: A CASE STUDY OF DIGITAL SOIL MAPPING OF SOIL CARBON AND NITROGEN IN WEST JAVA, INDONESIA Setyono Hari Adi
Widyariset Vol 3, No 2 (2017): Widyariset
Publisher : Pusbindiklat - LIPI

Pedotransfer functions (PTFs) for the tropical region were developed to model topsoil total carbon and nitrogen variations, by using input parameters of Digital Elevation Model—DEM, Normalized Difference Vegetation Index—NDVI and bioclimatic variables. Puerto Rico dataset was used to develop the model, while West Java, Indonesia was chosen for the model application. Using 22 input parameters derived from the three soil forming factors (relief, vegetation, and climate), the PTF could explain 71% and 66% of the soil total carbon and nitrogen variations, while comparable results were obtained from reduced input parameters (RMSE 3.12% and 0.05% for topsoil total carbon and nitrogen, respectively). This result suggests that application of PTFs to model soil properties variation, especially in the tropical region, could be used to generate reliable pre-assessment information to support decision making in the land productivity improvement plan.

LENGTH DISTRIBUTION AND SEX RATIO TO INVESTIGATE SPAWN ELIGIBILITY OF BIGEYE TUNA(THUNNUS OBESUS LOWE, 1839) IN THE INDIAN OCEAN Arief Wujdi; Fathur Rochman; Irwan Jatmiko
Widyariset Vol 2, No 1 (2016): Widyariset
Publisher : Pusbindiklat - LIPI

Bigeye tuna (Thunnus obesus Lowe, 1839) is the important commodity for the fishing industry in Indonesia. Increased exploitation is threatening their population, so that is necessary to monitor the size composition that meets the eligibility to be captured, as well as the sex ratio as a management measure. Data was collected by scientific observers program which was following commercial tuna longline operation mainly based in Benoa, Palabuhanratu and Bungus Fishing Port from August 2005 to December 2014. Chi-Square analysis with 95% of confidence level also implemented to determine the sex ratio of female and male. The result showed that BET caught ranged from 30 to 192 cm, mode size ranged from 121 to 125 cm and mean 111,76 cm. As much as 69,5% of them was greater than a length at first maturity (Lm) and that means have been worthy to be captured. The sex ratio of (F:M) 1:1,32 was observed which indicates male was dominant than female. Correlation between sex ratio and length proved to be significant where the female was increasing in size between 95-145 cm, as described a regression equation. However, an equal sex ratio occurred during December to January and also from April to June along the southern part of Java and East Nusa Tenggara and western part of Australia waters.

ANALYSIS OF CLIMATOLOGICAL THERMAL COMFORT IN DKI JAKARTA USING HEAT INDEX (HUMIDEX) Trinah Wati; Riri Indriani Nasution
Widyariset Vol 4, No 1 (2018): Widyariset
Publisher : Pusbindiklat - LIPI

Interactions between human and environment about the influence of the physical atmosphere’s state or weather on human is expressed in com- fort level. The complex relationship between health and weather factors with human comfort is defined as biometeorological index. One of the biometeorological indices is heat index called as Humidex. Studies about Humidex in Jakarta were conducted using climate data stations of Indonesian Agency for Meteorology, Climatology and Geophysics (BMKG), namely air temperature, relative humidity and wind speed daily average during 1985 to 2012. The purpose of this study was to determine the level of thermal comfort using heat index Humidex in Jakarta and its climatological trends during 1985 to 2012. Comparative analysis between Humidex and the wind speed and also with the number of vehicles in Jakarta were conducted to determine their impact to the heat index in Jakarta. The results showed that the Humidex monthly average in Jakarta ranged between 36,1 °C and 39,5 °C. Humidex monthly pattern had two peaks with the first peak was on May and the second one was on November, while the lowest value was recorded on August and January. Humidex in Jakarta tended to increase between 0.05 °C and 0.08 °C with its coefficient of determination (R2) was between 0.36 and 0.71. The effect of wind speed to Humidex was lowering the value of Humidex which increased the thermal comfort. Meanwhile, the number of vehicles showed a tendency to grow exponentially, which affected the further decline in thermal comfort level in Jakarta.

DIVERSITY OF ENDOPHYTIC BACTERIA ASSOCIATED WITH (Curcuma heyneana) AND THEIR POTENCY FOR NITROGEN FIXATION Tri Ratna Sulistiyani; Puspita Lisdiyanti
Widyariset Vol 2, No 2 (2016): Widyariset
Publisher : Pusbindiklat - LIPI

Endophytic bacteria shows a high biodiversity and some of the species plays important biological roles in agriculture. The aim of this study was to investigate the endophytic bacteria diversity associated with temu giring (Curcuma heyneana) and to evaluate its nitrogen-fixation activity. Temu giring was collected from Bogor Botanic Garden. The isolation of endophytic bacteria was carried out using two methods (spread plate and plant piece methods) and four different medias (Nutrient Agar (NA), NA contained temu giring extract (NAH), Water Yeast Extract Agar (WYEA), and WYEA contained temu giring extract (WYEAH)). The identification of selected isolates were conducted based on 16S rDNA. The ability of selected isolates to fix the nitrogen on Jensen’s media is then being tested. The results revealed that the suitable method and media of endophytic bacteria isolation were spread plate method and NA. Based on the morphological characteristics differentiation, 30 isolates were obtained from rhizome (27%), stem (50%), and leaves (23%). The sequencing result of 16S rDNA showed that community of endophytic bacteria was divided into six clusters, those are Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Flavobacteriia, Actinobacteria, and Firmicutes,which represented 17 genus consisted of Microbacterium, Leclercia, Brevundimonas, Chromobacterium, Enterobacter, Acinetobacter, Novosphingobium, Chryseobacterium, Curtobacterium, Agrobacterium, Sphingomonas, Herbaspirillium, Bacillus, Variovorax, Mycobacterium, Starkeya, and Rhizobium. A total of eleven isolates could grow in the N free medium. The presence of endophytic bacteria those were able to fix nitrogen are expected to be applied in agricultural sector as a biological fertilizer.

Page 42 of 49 | Total Record : 485

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Pusbindiklat Peneliti-LIPI (The National Training and Education Center for Researchers Development – Indonesian Institutes of Sciences) Jl. Raya Bogor Km. 46, Cibinong Science Center Cibinong - Bogor 16911

Location
Kota adm. jakarta selatan,

Dki jakarta

INDONESIA