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Articles 583 Documents
KONDUKTIVITAS TERMAL PAPAN PARTIKEL SEKAM PADI Wibowo, Hary; Muhajir, Khairul; Rusianto, Toto; Arbintarso, Ellyawan
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (121.247 KB) | DOI: 10.34151/technoscientia.v1i1.375

Abstract

People have used rice husk as an isolator material to prevent melting block of ice by pour it to the block of ice. Rice husk as particle board have been developed as an alternative of isolator material especially for cold storage. Thermal conductivity was affected by many aspects; one of them is filler solid compression ratio. The value of thermal conductivity in the rice husk particle boards has been researched to thermal conductivity with modified of ASTM C177 method and with different solid comparison are: 6-1, 5-1, 4-1, 3-1 i.e from original thick to final thick. From the different of the value of thermal conductivity which was from every density, it was found that the highest value of the thermal conductivity was obtained on rice husk particle board with the density of 3-1 with the value of thermal conductivity 0,133 w/m°C on heat source 70 watt and 0,103 w/m°C on heat source 80 watt and the lowest value of the thermal conductivity was density with 6-1 with the value of thermal conductivity 0,096 w/m°C on heat source 70 watt and 0,082 w/m°C on heat source 80 watt.
ANALISIS PENENTUAN UKURAN LOT PEMESANAN MENGGUNAKAN METODE JOINT ECONOMIC LOT SIZE (JELS) DI PT. FORESTALESTARI DWIKARYA TANJUNG PANDAN Sodikin, Imam; Mudiarti, Ismi
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (149.681 KB) | DOI: 10.34151/technoscientia.v1i1.376

Abstract

The development in industrial world brings a big effect in management of company. Supply chain management is the best solution for increasing prime competitive, with target inventory of management between buyer and supplier. On conventional inventory of management, vendor calculates lot size production policy independently like that with buyer. Optimize of Economic Order Quantity’s vendor not same with Economic Order Quantity of buyer. This problem can finish if there negotiation or joint policy (Joint Economic Lot Size). The examination aims to determine optimal joint policy between buyer and vendor. Result of analysis the set of contract number 1 is optimal for vendor with first order quantity (Q1) = 4,481.02 ton, z1 = Rp 24,590,458.32 and second order quantity (Q2) = 1,542.29 ton and z2 = Rp 847,232 with bargaining the vendor’s expected bargaining surplus is given by Rp 19,251,181.95 so, with this contract buyer and vendor gets profit’s.
NOx REDUCTION BY ADSORPTION AND HYDROGEN-SELECTIVE CATALYTIC REDUCTION USING Pt-ZEOLITE : PART I. SPECTROSCOPIC STUDY AND EFFECT OF TEMPERATURE TO ACTIVITY Fatimah, Is; Hidayat, Arif
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (174.996 KB) | DOI: 10.34151/technoscientia.v1i1.378

Abstract

In this paper, spectroscopic investigation on NOx adsorption and Hydrogen- Selective Catalytic Reduction (H-SCR) by using Pt-zeolite and also study on the effect of temperature to the % activity of reduction are presented. FTIR and UV-Visible spectro-photometry reveal the chemisorption occure during NOx adsorption by Pt-zeolite. Fur-thermore in the effect of temperature study, it concluded that both of processes significantly affected by temperature. Arrhenius model is used to predict this effect and the result show that activation energy of NOx reduction in H-SCR system is 0.2640 Joule/mol and adsorption energy is 4.0617 Joule/mol.
STUDI GEOLOGI PENDAHULUAN EKSPLORASI BIJIH BESI DI KECAMATAN PELAIHARI KABUPATEN TANAH LAUT PROPINSI KALIMANTAN SELATAN Prasetyanto, Inti Widi
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (121.45 KB) | DOI: 10.34151/technoscientia.v1i1.379

Abstract

The aim of this preliminary geological study is to know the field conditions from iron ore, in the Gunung Tembaga, surrounding in Pelaihari District, Tanah Laut Regency, South Kalimantan Province, consist of geomorphological, stratigraphy and structural geo-logical aspect. Meanwhile the goals of the study is to know iron ore spreading in surface and its possibility occurrence in sub surface. The exploration methods has been done were preliminary geological survey and mapping consists of reference study, geological surface mapping, rock sampling and laboratory analysis. The Geomorphologically study area consists of undulating hilly with elevation from 30 until 80 meters. This morphology formed metamorphic rocks consists of schistfilit and igneous rocks consists of gabbro-peridotite. Those rocks overlay by colluvial deposits which found mafic igneous rocks fragment and iron ore scattered from sand, pebble until cobble. Structural geology in study area are joint and drag fold. Iron ore mineral in study area are magnetite, hematite and limonite which predicted from magmatic, replacement, residual or oxidation processes. Iron ore samples from study area show Fe value 66,14% and 66,20%.
MODEL ROTATING CYLINDER ELEKTRODE UNTUK MENENTUKAN KEPERLUAN RAPAT ARUS PROTEKSI KATODIK Utami, Isni
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (526.049 KB) | DOI: 10.34151/technoscientia.v1i1.380

Abstract

Effect of fluids flow rate onto necessity of current density cathodic protection which characterized using Rotating cylinder electrode (RCE) model has been researched on an electrochemistry manner. This research was done to AISI 1018 steel as the electrode spinning cylinder-shaped inside aerated dissolvable NaCl 3.5%. using variation spinning rate 0-2000rpm and 25-75 0C temperature. Current density cathodice protection necessity determined from the steel interface potential -800mV with reference anode Ag/AgCl. Experiment result shows as the increasing of electrode rate, cathode protection current density needs increased due to diffusion layer tare faction and also because corrosion potential become more positive. Higher temperature would increasing cathode protection current density needs and makes corrosion potential more negative. Oxygen activation energy value to be diffused onto electrode surface support the corrodibility AISI 1018 toward temperature increment, because cathode reaction controlled by transfer mass of dissolved oxygen. With un-dimensioned number analysis and data experiment calculation, empiric formula which is functional relation between electrode rate/fluids flow rate characterized as turbulence flow toward cathodic protection current density is mentioned below: iPRCE = 0,0841 0,6539 0,4976
APLIKASI IC AT89S51 SEBAGAI PENGONTROL KECEPATAN MOTOR DC -, Mujiman
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (249.336 KB) | DOI: 10.34151/technoscientia.v1i1.381

Abstract

Controlling is tool up to can work as according to what expected by consumer. At controlling of speed of motor dc, matter which is most commonly done voltage regulation. Controlling design speed motor dc uses the IC AT89S51 as especial component at network. Govern the input by knob depress, processed at network of IC AT89S51, and output through of IC ULN200x (as driver), with the motor of dc stepper as controlled burden. LED use as indication of speed choice. Result of perception prove that with the arrangement of speed of motor rotation use the network microcontroller compared to a calculation theory of there are smallest error at low rotation.
OPTIMASI KONDISI PROSES EKSTRAKSI MINYAK BIJI PEPAYA Yuniwati, Murni; Purwanti, Ani
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (146.657 KB) | DOI: 10.34151/technoscientia.v1i1.382

Abstract

The papaya (Carica papaya L.) is a member of the small class dycotyledoneae, family caricaceae, and genus cariaca. This plant is native to the Central America and West Indies. It grows well at the tropical region with elevation 600-700 m above the sea level. Today papaya seed is only throwed away as a waste product, whereas in fact the papaya seed contains fatty acids with higher economic value which is called papaya oil. Oil of papaya seed can be obtained from solid - liquid extraction method. In this investiga-tion, the extraction of papaya seed was carried out in the stirred reactor with ethanol as a solvent. Solvent-extracted oil was distilled to separate papaya seed oil from solvent. The variables of investigation were extraction temperature, stirring speed, ratio between sol-vent volume and mass of papaya seed, and size of papaya seed. The extracted oil was a-nalyzed by using gas chromatography to determine the fatty acid composition. The opti-mum condition of papaya seed extraction were obtained at extraction temperature 300C, stirring speed 397 rpm, ratio between solvent volume and mass of papaya seed at 25 : 1, and size of papaya seed (-14/+20) mesh or average diameter 0.08 cm. The correlation between mass transfer coefficient and these variables is shown in the dimensionless e-quation below : Sh = 8,89 (10)5 Re(0,7785). Sc 0,9411.With the average error is 0.9706%.
STUDI SIFAT-SIFAT KIMIA TANAH PADA TANAH TIMBUNAN LAHAN BEKAS PENAMBANGAN BATUBARA Ernawati, Rika
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (118.003 KB) | DOI: 10.34151/technoscientia.v1i1.383

Abstract

Coal mining activities must be followed by reclamation effort. If it was not done, environmental degradation would have occurred such as soil quality changes, not only physically but also chemically. Reclamation conducted by re-vegetation on abandoned mined area (mined out). This research aim is to study chemical soil properties on waste disposal of mined out at PT. Tambang Batubara Bukit Asam (PTBA), South Sumatera. The method of the researches were survey and laboratory analysis. Sampling method use the Purposive Sampling based on age of land. Chemical soil properties were analyzed is Cation Exchange Capacity (CEC), Organic Matter (OM), Base Saturation (BS), available phosphor, nitrogen and available potassium. The result of this research showed that CEC have low to high class (10,98-38,57me/100g) , BS in East of Pit 3 is very high class (97,44-99,80%), whereas West of Pit 3 and North of Pit 1 is very low to low class (8,15-20,16%). OM is very low to low class (0,57-3,45%). Available phosphor is moderate to very high class (20,31-43,67ppm). Nitrogen is very low to low class 0,01-0,12%). Available potassium generally is very high class (66,16-169,12 ppm). Analyze result that prosperity degree based on chemical soil properties namely CEC, BS, OM and phosphor at re-search area have prosperity status is very low to very high.
PEMBUKTIAN POLA PANCARAN GELOMBANG RADIO (RF) MENGGUNAKAN METODE PELACAKAN SINYAL (TRACKING) DAN APLIKASI SURFER Kristiyana, Samuel
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (252.07 KB) | DOI: 10.34151/technoscientia.v1i1.384

Abstract

Antenna is a physical structure made from metal conductor as a medium between of transmission electromagnetic wave of standing wave and as free space wave in the air which is capable of carrying information signal. The antenna structure will give specific ra-diation pattern around it. Radiation pattern cannot see with eyes but really can transmissi-on of signal so far. Radiation pattern of electromagnetic wave has understood using soft-ware application. Position of place observation and signal strength around of transmitter antenna are needed to analysis with tracking method.
ANALISIS PENGARUH PENAMBAHAN KODE PENEBAR PADA MODULASI GMSK TERHADAP DSCDMA DAN OFDM DITINJAU DARI BER SISTEM Al Sasongko, Sudi Mariyanto
JURNAL TEKNOLOGI TECHNOSCIENTIA Technoscentia Vol 1 No 1 Agustus 2008
Publisher : Lembaga Penelitian & Pengabdian Kepada Masyarakat (LPPM), IST AKPRIND Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (189.858 KB) | DOI: 10.34151/technoscientia.v1i1.385

Abstract

The important parameter to justify the performance of a communication system is the value of Bit Error Rate, which should be small enough, the use of limited bandwidth, and the use of limited power emission. Some popular applied modulations in wireless communication for high data rate are GMSK in GSM system, QPSK in DSCDMA system, and QAM in OFDM system. This research was to simulate the performance of Bit Error Rate of GMSK which was added with a spreading code in data input.The evaluation of Bit Error Rate is done on Direct Sequence GMSK baseband and passband, Direct Sequence CDMA passband, and OFDM 64QAM baseband through AWGN channel and Multipath channel. Procedure of evaluation is simulate model with increasing SNR every 1dB until reaches threshold of BER as 10-4 . Analysis is based on program simulation in Simulink Matlab 6.5.1. Based on simulation result , for AWGN channel with threshold BER as 10 – 4 are found : DSGMSK passband have level need 1,5dB, DSCDMA passband have level need 7,5dB, DSGMSK baseband have level need 10dB, and OFDM baseband have le-vel need 27dB. In multipath channel environment, DSGMSK passband configuration is need 1,5dB less than DSCDMA configuration that are 6dB and 7,5dB.

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