Jurnal Teknosains
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TEGANGAN RESIDU KEPING ARESTER SEBAGAI FUNGSI DARI CACAH KEPING ARESTER
No full textIndonesia is a tropical area with a high intensity of repeating lightning strikes. The voltage is produced by lightning by increasing the presence of sensitive loads. Therefore, lightning can easily worsen the quality of consumer power, even if the generated voltage is relatively low. Lightning strikes can cause excessive voltage along the power lines. Its propagation can cause a voltage surge on low voltage systems, which can damage the equipment. Maintenance and protection against lightning strikes are necessary for the prevention of such damage. Arrester is a device that is intensively used nowadays by the general public to protect equipments from lightning strikes. It is used to protect the system from the danger of lightning by flowing current into the ground and leaving a certain resistance value, so that the system does not experience a surge voltage.This research was conducted through laboratory-scale testings using several major equipments, such as a high voltage generator, an impulse voltage generator, and an oscilloscope. Modifications of the tests were done using one to four 220 volt low voltage Merlin Gerin LTD arresters arranged in series, with a maximum current of 6.5 kA . Calculations using equations for low voltage circuit in series were done for more than four arresters. From the test results, it was found that the characteristics of the arrester residual voltage will rise when connected in series. Low voltage arresters can be used for higher voltage requirements by counting the number of arresters needed. The equation for the number of arresters in series required to cut the overvoltage surge is y = 0.694x – 0.106. Therefore, if more than 4 arresters will be needed, the residue voltage can be estimated through this formula.
PENETUAN ALE DAN AE LARVA LEPIDIOTA STIGMA F PADA TANAMAN TEBU
No full textThis research was conducted to determine the value of Economic Injury Level (EIL) and Economic Threshold (ET) for the larvae of Lepidiota stigma instar 1, 2 and 3 in three different locations. The amount of larvae population and plant per m2 in the field, and the weight proportion of the vanished root or to-be-eaten by a larva were needed to determine the loss of result per m2 data on the maximum harvest outcome and the harvest outcome in the field per m2. The highest proportion value of the outcome loss per m2 based on the Walker Model, which has been modified on biological control with Nematode Entomo Patogen (NEP) Steinernema spp. combined with light trap, was in Tempel Sari, i.e. larvae instar 1 (0.0108), instar 2 (0.0174), and instar 3 (0.0221). The lowest value was in Grenjeng, i.e. larvae instar 1 (0.0048), instar 2 (0.0078), and instar 3 (0.0099). There were significant differences among the three instars, where the consumption greediness of instar 3 is higher than instar 1 and 2, so the proportion value of the outcome loss per m2 of larvae instar 3 in the respective locations was higher than that of the two other instars. Determination of EIL value based on the Bode & Calvin Models gave the highest EIL value in Grenjengwith larvae instar 1 in the amount of 15.50 with ET value 12.40, instar 2 in the amount of 9.59 with ET value 7.67, and instar 3 in the amount of 7.54 with ET value 6.03. On the other hand, the lowest EIL value was found in Tempel Sari, with larvae instar 1 in the amount of 6.97 with ET value 5.58, instar 2 in the amount of 4.31 with ET value 3.45, and instar 3 in the amount of 3.39 with ET value 2.71.
DAMPAK DAN KENDALA WISATA WADUK SERMO DARI ASPEK LINGKUNGAN HIDUP DAN RISIKO BENCANA
No full textSermo Reservoir is a multipurpose reservoir. Due to its natural beauty and being the only reservoir in Yogyakarta Special Region, it is visited by many tourists. Tourism activities in the reservoir may cause environmental impacts and disaster risks for the tourists. This study aims to determine the potential of Sermo Reservoir as a natural tourism object and, in general, analyze the environmental impacts and disaster risks caused by tourism activities. The study was conducted by field surveys, observations and interviews with the local community. Reservoir water samples were collected for physical and chemical parameter analysis and were evaluated against the standard requirements of water for tourism activities. Data analysis was performed using descriptive qualitative and quantitative methods, using tables and diagrams of the processed data. In general it was found that the Sermo Reservoir has high potential for tourism. However, due to the lack of supporting facilities, the number of tourist coming to the Sermo Reservoir is still not yet optimal. The environmental impacts caused by tourism activities have occurred. The positive impacts that arise are the emerging business opportunities and the increased revenue of the local people, while the negative impacts are the pollution caused by solid waste and the water quality degradation. The risk of disaster may come from accidents when conducting activities in the reservoir, and it should be considered in the development of Sermo Reservoir for tourism
HUBUNGAN ANTARA INDEKS VEGETASI NDVI (NORMALIZED DIFFERENCE VEGETATION INDEX) DAN KOEFISIEN RESESI BASEFLOW PADA BEBERAPA SUBDAS PROPINSI JAWA TENGAH DAN DAERAH ISTIMEWA YOGYAKARTA
No full textThe background of this research is the decrease of environment capacity in cacthment ecosystem, especially impact of vegetation forest on behavior streamflow. The indicators of cacthment destruction can be seen through hydrograph characteristics. Evaluation of cactment respons of flow hydrographic as an evaluation tools of river catchment responses becomes very important to analyze because it is a benchmark in determination several policy about flood, drough, sedimentation and landslide handling. The research purpose is to analyze the relationship between vegetation index NDVI (Normalized Difference Vegetation Index) and the characteristic of baseflow recession coefficient at several subcatchment areas in province of Central Java and Specific District of Yogjakarta.The method of this research is surveillance on data recording of AWLR (Automatic Water Level Recorder) and data of River Flow Measuring Stations in order to separate the baseflow by calibration curve, and image interpretation of Landsat ETM+ for the transformation of vegetation index (NDVI-Normalized Difference Vegetation Index).The analysis on recession coefficient data (Krb) and NDVI were correlated to analyze the strength of relationship between these two parameters. The results of statistical analysis on index NDVI and recession coefficient showsthat NDVI and recession coefficient value at R2 is 0.1427, F = 2.17 which is not significant at 1% significance level of 0.1646. The result shows a very weak correlation of 0.077 which mean that vegetation density (NDVI index)has a very weak control on low flows. Basically, river baseflow is a genetic component of river flow which comes from aquifer storage and/or other low flow sources. Thus, geology and soil have a significant effect on baseflow
PENGEMBANGAN MATERIAL PASAK ENDODONTIK Ti/40HA DENGAN MENGGUNAKAN KONSEP FUNCTIONALLY GRADIENT MATERIAL
No full textCommercial endodontic pegs have a homogeneous composition and strength so that the transmission voltage of pegs to dentin often result in damage to the tooth root. The concept of functionally gradient material (FGM) is expected to overcome these problems by adjusting the mechanical properties of each peg to the nature of the teeth. This study aims to develop a material stake with the concept of FGM from Ti/40HA material that is composed of five layers with concentrations of HA from 0% - 40% wt through the process of uni-axial pressing followed by sintering at 1200oC and 1400oC in argon gas. Then performed on each layer characterization by SEM / EDX, the optimum sintering temperature was determined by test-t (p <0,05). Morphological Testing showed that the composite of Ti/40HA still porous, while EDX shows the composition of Ca and P increase as an indication of increment in the concentration of HA as the decrement in concentration of the layer-1 (100% Ti) up to layer-5 (60% Ti-40% HA). In conclusion, Ti/40HA200 and Ti/40HA200 composite materials can be produced by decreasing its roughness as the rising concentrations of HA in each section
UJI BIOKOMPATIBILITAS KOMPOSIT POLIVINIL ALKOHOLHIDROKSIAPATIT DENGAN PENGUAT CATGUT SEBAGAI BAHAN PENYAMBUNG PATAH TULANG
No full textBone fracture fixation devices have been using rigid metallic materials such as titanium, titanium-alloy or cobalt chrome. Besides having some advantages, the titanium fixation devices also have disadvantages, such as too high strength and stiffness. This continuously stimulates the bone, causing bone atrophy under the plate, further disrupting the growth of bones, especially in children. Other deficiencies of this metal material is its sensitivity to temperature changes and the spread of metal ions in several organs. Some of these shortcomings led to the need for a secondary operation. Bone fracture fixation devices, such as the poly-l-lactic acid (PLLA), can be absorbed by the body and show some other advantages. However, it also has some drawbacks due to the high crystalline products during the degradation process. Lactic acid monomer released after degradation causes cellular response at the implant site, which facilitates the release of chemical mediators, such as prostaglandine by fibroblasts and macrophages as a cause of bone resorption. Therefore, this study aimed to develop the use of other polymeric materials that have good biocompatibility,appropriate mechanical strength, and can be absorbed by the body, such as Polyvinyl Alcohol (PVA). Previous research suggests that the PVA-HA composite with catgut reinforcement has sufficient and stable mechanical strength to be used as bone fracture fixation material. The purpose of this study is to know whether the PVA-HA composite with catgut reinforcement has good biocompatibility without toxicity and hypersensitivity effects in experimental animals. Biocompatibility testing includes local cytotoxicity and type IV contact hypersensitivity test. This type of research is experimental in vivo laboratory using wistar rats (Rattus norvegicus). Testing is done through two phases, in which induction or sensitization phase is done by rubbing PVA-HA composite with catgut reinforced ointment powder on the ears that lasts up to 10 days. After being rested for 3 days, this is followed by a second phase contact (elicitation) on day 14 and observed in the period of 24, 48, and 72 hours. Observations were made macroscopically and ear thickness was measured with a micrometer. Local toxicity testing is done by implantation of PVA-HA composite with catgut reinforcement on the back catgut of wistar rats. After a certain time period, the implant material is opened,examined, and observed histologically under a light microscope. The results showed no discoloration or induration on the animal ears in all treatment and control groups, both for the sensitization and the elicitation phase. One way ANOVA statistical test showed that there were no significant differences in the results of measurements of the thickness of the wistar rats ears from all treatment groups before and after treatment on measures 24, 48 and 72 hours (ρ >0.05). Microscopic examination showed no infiltration of acute inflammatory cells such as neutrophils, basophils or eusinofil, and chronic inflammatory cell infiltration such as macrophages, lymphocytes and plasma cells. It can be concluded that the PVA-HA composite with catgut reinforcement is a material that does not cause toxicity and hypersensitivity in experimental animals, thus potentially can be used as bone fractures fixation material.
MENGGUNAKAN SERANGGA UNTUK MEMAHAMI KEHIDUPAN
No full textSerangga ternyata memiliki tempat yang sangat istimewa dalam ilmu pengetahuan.Kalau selama ini lebih banyak mengenalnya sebagai jasad pengganggu (Istilah pertaniandikenal sebagai OPT atau Organisme Pengganggu Tanaman dan Istilah kesehatan dikenalsebagai vektor pembawa penyakit), maka dalam ilmu pengetahuan secara lebih umumperan serangga bukan hanya sebagai penyebab kerugian dan kerusakan saja. Serangga amatbermanfaat atau berjasa kepada ilmu pengetahuan dalam menambah khazanah pemahamantentang jasad hidup dan berbagai interaksi yang terjadi pada jasad hidup, termasuk manusia
PENGARUH KATALIS BASA (NaOH) PADA TAHAP REAKSI TRANSESTERIFIKASI TERHADAP KUALITAS BIOFUEL DARI MINYAK TEPUNG IKAN SARDIN
No full textBiofuel is an alternative diesel engine fuel is produced from oils/fats of plants and animals (including the fisheries industry waste) through the esterification and transesterifiksi reactions. A transesterification is reaction to form esters and glycerol from trigliserin (fat/oil) and bioalcohol (methanol or ethanol). Transesterification is an equilibrium reaction so that the presence of a catalyst can accelerate the achievement of a state of equilibrium. Process of the transesterification reaction of sardine flour oil waste with NaOH as base catalyst in producing biofuels was conducted.The research purpose has studied the influence of NaOH concentration in transesterification process and examinate its effect on the quality of biofuels production, conversion, and physic quality. The variables that analysed was the effect of NaOH concentration as catalyst (0.5%, 1.0%, 1.5%, and 2.0% from amount of oil and methanol) in the transesterification reaction step. The result showed that the increasing NaOH concentration (0.5 - 1.5%), enhanced the biofuel conversion (%). The highest conversion of biofuels was achieved by using 1.50% NaOH (w/w) with 45.34% biofuels conversion. The major component in the biofuels was methyl palmitate (20.31%). ASTM analysis data also supported that the biofuel product was in agreement with automotive diesel fuel specification
METODE PENGENALAN POLA TRABEKULA MANDIBULA PADA RADIOGRAF PERIAPIKAL DIGITAL UNTUK DETEKSI DINI RISIKO OSTEOPOROSIS
No full textOsteoporosis is a sistemic skeletal disease. Osteoporosis examination using the gold standard determined byWHO, namely DEXA, is relatively expensive and the result can not show the bone microarchitecture. Meanwhile,the probability of advanced age women to visit a dentist is relatively high. If the condition of bone mass densitywhich indicate osteoporotic condition can be recognized from the trabecullar pattern of mandible, so the dentistcan participate in early detection of a patient having a risk of osteoporosis. The objective of this research is to getthe pattern recognition method which can be applied to digital periapical radiograph that characterize the bonemass density condition. Combination of Sobel’s edge detection with the binary image has been applied to the image,producing an image showing the mandible trabecullar pattern visually. Supported by fractal dimension value andfind local maxima in the binary image, the pattern can be better distinguished for each condition of osteoporosis,osteopenia, and normal. The value of fractal dimension and find maxima is positively correlated with the bonemass density
Analisis Pengaruh Bentuk Telapak Kaki Terhadap Kelelahan Fisik
No full textPhysical activity over time can cause fatigue during exercise such as walking or light running. Physical fatigue effects on heart rate and blood pressure. Factors that can cause fatigue are gender, cardiovascular disease status, sport exercise habits, BMI (Body Mass Index) and study activities during a week. Physical fatigue also could be caused by factors shape of your foot, especially the form of flat feet/pesplanus in type 1, 2or 3. Subjects of this research were students of Industrial Engineering Gadjah Mada University ages 19 to 23 years with the aim of sampling techniques to the criteria of having normal or flat feet. The subjects run normally using a tread mill with a speed of 4 miles per hour for 6 minutes. The variables measured were heart rate and blood pressure. Heart rate was measured in three sessions among others before, during and after the experiment using a heart rate monitor while blood pressure was measured before and after the experiment. There are significant differences in systolic blood pressure before and after the experimental on indicator of sex, heart rate after experimental on indicator of disease status and heart rate on indicator exercise habit for normal feet. Then in the form of pesplanus foot type 1, there are significant differences like systolic and diastolic blood pressure after experimental on indicator of BMI (Body Mass Index) and systolic blood pressure on indicator of pre-experimental study activities during a week, in which a significant difference in respondents who did not have study activities of the respondents who went tocollegein6-10 hours. In the form of pesplanus foot type 2 there is a significant difference in heart rate when experimental on indicator of cardiovascular disease status