bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sound absorption characteristics of the natural fibrous material from coconut coir, oil palm fruit bunches, and pineapple leaf
Authors: Rusli M , Irsyad M , Dahlan H , Gusriwandi  , Bur M 
Published: September 2019

Abstract
In this paper sound absorption characteristics of three kinds of natural fiber composite is evaluated. The fibers are made from coconut coir, oil palm fiber from empty fruit bunches, and pineapple leaf. The sound absorption coefficient is evaluated using a specimen thickness of 10 mm and 20 mm and two variants of fiber density. A simple impedance tube with two microphones is used in the measurement. The sound absorption coefficient is calculated by the transfer function of the two microphones within 200 Hz to 3000 Hz frequency range. It is revealed that three types of fibers can reduce reflected sound in relatively higher frequency. Denser and thicker of a fibrous material increases the sound absorption of the material and shifts the peak of the absorption coefficient into a lower frequency. Furthermore, pineapple leaf fiber has the highest sound absorption coefficient among others type of fibers. Smaller and uniform fiber diameter has a significant role to absorb sound energy in pineapple fiber. Whereas, coconut coir and palm empty fruit bunches fiber have larger, various and random fiber diameters, that could make the sound absorption coefficient become lower, especially within the frequency range of measurement.
Natural frequencies of twisted cantilever beam
Authors: Malta J , Jefri  , Bur M , Satria E 
Published: September 2019

Abstract
This research is conducted to determine the natural frequencies of a twisted beam with different orientation of principal axes numerically using Autodesk Inventor. Further, the results are compared experimentally. To simplify in the analysis, the twisted cantilever beam is divided into two segments model. The orientation between two segments is simulated and tested variously. The natural frequencies obtained numerically and experimentally are selected only in transverse vibration based on the simulation of each mode shape of the cantilevered beam. In general, the natural frequencies of the simulated cantilever beam and experiment results tend to similar results.
Optimization of matrix compositions of Al2O3, SiO2, Caolin, and CaO on the mechanical properties of a geopolymer composite with short carbon fiber
Authors: Akmal J , Badaruddin M , Ismoyo M K , Yuwono S D 
Published: September 2019

Abstract
Geopolymer is a material synthesized from a base material with a large amount of silica and alumina. Geopolymer can be used as an affordable alternative as a substitute for Portland cement, reducing pollution, and resistant to fire under certain conditions. But pure geopolymer has not been widely used in industrial areas because overall it has low toughness and mechanical properties when compared to metals or ceramics. This research was conducted to produce geopolymer composite material with good mechanical properties and can be applied as a material in making environmentally friendly pipes, by identifying the influence of the composition of the geopolymer base material using the Taguchi method. Generate Geopolymer composites with the addition of Silica Powder and random short carbon fiber have good mechanical properties, from the results of the experiment produced the best flexural strength in T9 specimens with details of the composition of Silica Powder (27 g), Kaolin (55 g), CaO (6 g), and Carbon Fiber (13 gr) with a flexural strength of 41.46924655 MPa and flexural modulus 6 GPa.
The effect of solar water heater performance by variation of the plate shaped
Authors: Harun D , Maulana M I , Akhyar  
Published: September 2019

Abstract
The vital component of a solar water heater system is a solar energy collector which is also known as a heat absorber unit. Solar collectors or heat absorbers can convert from solar radiation energy into thermal energy. So the aims of this study to experiment the increasing of water temperature caused by the variation of the solar water heater collector plate. The methodology of this experiment has variated the shape of the plate absorber from the flat plate collector named as plate collector A (quadrangle-folded), and a flat plate collector called as B plate collector B (triangle-folded). The collector uses a stainless steel plate with a dimension of 1.5 × 0.8 m where each collector has a variety of plate folded. Fluid flowed through a 1 inch (diameter) copper pipe with 1.4 m of length and isolated using rubber to minimize wasted heat. The results show that flat plate collector B has a higher efficiency compared to the flat plate collector A. The highest of fluid output temperature found in collector B at 67 °C and a solar intensity is 1198 W/m2. The highest useful energy is 209.91 Watts at 13.30 WIB (Western Indonesia time), and the highest efficiency is 16.23% at 13.00 WIB (in collector B).
Analysis cutting forces and surface roughness of fibre reinforced polymer for end mill processes
Authors: Ridwan F , Havendri R , Susanti O , Gusriwandi  , Yulhizhar  
Published: September 2019

Abstract
This study aims to determine the cutting force characteristics when cutting composite workpieces material. Cutting force is one of the cutting conditions that can determine the machinability of the workpiece. Composites have different mechanical properties from metals thus the machinability characteristics of composites will also be different compared to metals. In this research, cutting force of two GFRP workpieces consisting of chopped strand mat and woven roving type glass fibers with resin matrix was measured using a dynamometer and recorded using DAQ then the surface quality of the workpieces was analyzed. The cutting force and surface roughness characteristics are then compared to the cutting force of Perspex and Aluminium workpieces. The results show that the average cutting force measurement (Ftm) of GFRP Chopped strand mat, GFRP woven roving, Aluminium, and Perspex were 146.8845 N, 103.3915 N, 97.6002 N and 65.33 N resulting in surface roughness of 3.8511 µm, 5.2733 µm, 6.127 µm, and 6.23 µm respectively.
Surface characterization of the ceramic coating process on aluminum matrix composite reinforced particulate
Authors: Sukma H , Rahmalina D , Sulaksono B , Pane E A 
Published: September 2019

Abstract
Particulate-reinforced aluminum matrix composite for automotive components are developed since they have light density, high strength, and hardness, wear-resistant properties also low heat expansion coefficient compared to ferrous metals. An important factor that influences the composite characteristics is the condition of the interface area between the particle and the aluminum matrix with optimal wettability and minimal cavity defects. This research aims to improve hardness on particulate-reinforced aluminum composite which produces by a squeeze casting manufacturing process and ceramic coating process. Steps of this research include the development of an aluminum matrix composite manufacturing processes, which is followed by a ceramic coating process. Matrix composite material made of Al-7Si-9Zn-6Mg matrix with strengthened of 10% alumina (Al2O3) and 10% silicon carbide (SiC) particles, while for coating materials using Chromium Oxide, Aluminum Oxide, and Ez Zirconium. The results of the hardness test without the ceramic coating process are an average of 71 HRB (127 HV). After the coating process, an obtained hardness value of 163 HV for coating material of Chromium Oxide, 373 HV for Aluminum Oxide, and 338 HV for Ez Zirconium. The wear resistance test results in abrasion values of 2.222 x10-6 mm2/kg for coating materials of Chromium Oxide, 1.633 x 10-6mm2/kg for Aluminum Oxide, and 7.021 x 10-6mm2/kg for Ez Zirconium.
Mechanical properties of mild steel by adding Theobroma Cacao Peels Extract (TCPE) inhibitor
Authors: Yetri Y , Gunawarman  , Hidayati R , Zamri A 
Published: September 2019

AbstractThe ability of corrosion inhibitorTheobroma cacaoPeels Extract (TCPE) has been tested to improve the mechanical properties of mild steel after corrosion occurred. These properties were examined to measure its hardness, tensile and fatigue. Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) was used to analyze the morphology of the surface. The corrosion rate was found reducing, on the contrary, the efficiency was increasing as the increasing concentration on the extract. This raising was followed by an increase in mechanical properties, namely hardness, strength and fatigue strength. Indeed, the presence of absorption on the surface of the data was reinforced by EDX, X-ray photon spectroscopy (XPS), and AFM for topography. The addition of polar extract of cacao peels in HCl 1.5M is very useful to reduce the corrosion rate on the mild steel surface, and it can retain its mechanical properties after the corrosion occurred.
In vitro of Mg-1.6 Gd alloys after hot extruded for biomaterial application
Authors: Susanti O , Bachtiar E W , Harjanto S , Gunawarman  
Published: September 2019

Abstract
Mg-1.6Gd (wt%) alloys have attracted interest in biodegradable implant materials because of the potential to eliminate secondary surgeries. The purpose of this study was to evaluate the in vitro degradation performance of the alloys after the thermo-mechanical process (hot extruded and hot rolled) and to determine whether the materials are sustainable for further investigation. The performances of the Mg-1.6Gd alloys was using cell viability (MTT) test during the experiment. The results showed that verified viable the osteoblast cell on all the different thermo-mechanical process and no obvious toxic effect within the various time.
The Effects of the distance between ground-sill and double cylinder-piers against the scour patterns
Authors: Mera M , Thaahaa M 
Published: September 2019

Abstract
Flood disaster causes local scouring around the bridge piers. Some efforts to protect piers locally have been widely practiced, but the protective effect is only temporary. This is due to the riverbed being degraded within a few years, and eventually the pier protector is also broken. Ground-sill has a dual function of setting the ground level of the channel and stopping local scouring on the pier to continue. The present study is about physically modelling in the laboratory to observe scour depths due to the distance between the ground-sill and double piers. The position of the double piers remain, i.e. a line of flow direction, so there are upstream pier (called pier 1) and downstream pier (called pier 2). Only the ground-sill positions are varried. The ground-sill is located on the downstream of the pier 2. Some experiments are conducted to get the two best positions of the ground-sill by trial and error, that is W
1 (position 1) and W
2 (position 2) using the biggest discharge flow that can be. The position W
1 is better than W
2. This is based on two criteria: the scour depth has to be stable (no more scour) at the specified time range (0 - 120 minutes), and the maximum scour depth formed has to be the shallowest among those in the other experiments. The resulting two best positions of the ground-sill are then tested with three variations of discharge to observe the scour depth, and to observe the differences of the scour depths due to both piers in point 1 (behind the pier 1), point 2 (right side of the pier 1), point 3 (left side of the pier 1), point 4 (in front of the pier 1), point 5 (behind the pier 2), point 6 (right side of the pier 2), point 7 (left side of the pier 2), and point 8 (in front of the pier 2). The experimental results show that the maximum scour depth with the position W
1 occurs in points 1 and 3 with a 2.9 cm deep and a maximum flow of 3.161 l/s. Meanwhile the maximum scour depth with the position W
2 occurs in point 1 with a 3.8 cm deep and a maximum flow of 3.254 l/s. The scour characteristics with the point W
1 is that a local scouring occurs significantly since the beginning of the flow, but channel bed has been stable since several minutes after the flow starts overtopping the ground-sill. The flow with the position W
2 shows that the backwater affects significantly the flow condition so that scour and sedimentation process continuously occur. This experimentation also confirms that the control slope (the slope between riverbed where the piers are and the top of the ground-sill) has a optimum distance. In this study the optimum control slope is −0.014.
Analytical Network Process (ANP) for priority setting of strategic roads handling at Tebo Regency
Authors: Yosritzal  , Permana J , Istijono B , Hidayat B , Ophiyandri T , Gunawan H 
Published: September 2019

Abstract
Development of transportation infrastructure in the region aims to meet the needs of the community to facilitate mobility of people, goods, and services. However, the work of transportation infrastructure requires a large amount of cost while the development budget is limited. Therefore, a careful determination of the priority of road handling is urgently required. In this study, an analysis was conducted to determine the priority of handling strategic roads in Tebo Regency. This study uses the Analytic Network Process (ANP) method with 4 (four) criteria to determine the priority of road handling, namely: engineering, economics, regional potential, and policies. It was found that National Road - Pintas being the first priority with a weight of 0.252, then the second priority for National Road - Lubuk Mandarsah with a weight of 0.23.The third priority is Unit I Rimbo Bujang - Unit XI Rimbo Ulu Road with a weight of 0.211.
Simulation of the effect of floodway on Batang Kandis River flood control
Authors: Junaidi  , Marona S , Dalrino  
Published: September 2019

Abstract
Floods often occur in Padang City, mainly in the areas of Pasia Nan Tigo Village and Lubuk Buaya Village, caused by the overflow of Batang Kandis when heavy rains occur (intensity of rainfall >15mm/hours). To decrease the river overflow an artificial canal with 300 m long and 50 m wide (floodway) was constructed to bypassing the river flow from the Batang Kandis River to the ocean. In order to find out the effects of the floodway, four scenarios are performed the scenario 1 and 2 were the simulation condition of Batang Kandis River before and after the construction of floodway. While to increase the effectiveness of floodway, simulations 3 and 4 were carried out. Scenario 3 was the combination of floodway with normalization and embankment. To prevent the entry of seawater into the Batang Kandis River, because the floodway is affected by the tide of the sea, then 3-door motion weir was simulated namely scenario 4. Scenario 4 was the combination of floodway normalization, embankment, and a 3 door motion weir. From the simulations, we found that the floodway was effective to decrease the water surface level up to 15 m and 20 m during 10 years and 25 year return period of discharge respectively. From the scenario 3, we found that the embankment with 1.5 m and 2 m was effective to prevent overflow by 10-year and 25-year return period of discharge respectively. While for scenario 4 the water level rises 0.5 m due to motion weir So, that it is needed to extend the embankment with 0,5m high.
Intersection performance evaluation and designing intersection at concourse between arterial road and ramp of Medan-Kualanamu-Tebing Tinggi Highway
Authors: Amrizal  , Harahap A H S 
Published: September 2019

Abstract
In overcoming congestion problems that occur in Medan-Tebing Tinggi route, especially at certain points such as at Pasar Bengkel and Kayu Besar intersection during peak hours, an infrastructure has been built in, that is a highway which connecting Medan-Kualanamu-Tebing Tinggi. Medan-Kualanamu-Tebing Tinggi highway (MKTT) will connect Medan City and Tebing Tinggi City, so that drivers from Medan who will go to Tebing Tinggi will not pass through the main road that is prone to congestion.
There is an intersection that connects arterial roads with each MKTT toll gate. At the intersection, there is a conflict between flows from the opposite direction and intersecting, resulting in delays and queues along the intersection arm. The conflict occured because of the lack of designing of the intersection that drains the flow of vehicles from ramp to arterial road or vice versa. This needs consideration because of the congestion causes queues and delays, especially during peak hours and holidays, so that it requires intersection performance analysis at concourse between arterial road and ramp of Medan-Kualanamu-Tebing Tinggi highway and design the geometric of intersection which appropriate with this intersection.
From the results of the evaluation analysis, obtained degree of saturation at the intersection of the arterial road and the ramp of Lubuk Pakam toll road at 0.71 with level of service C that is still feasible to be used, so there is no need to change the intersection geometry. While for Sei Rampah, the degree of intersection saturation is 0.79 with the level of service D, which means that it is not feasible, requiring a change in the geometry of the intersection with a signalized roundabout. With the planned roundabout geometry, the degree of saturation is 0.5 which means it is feasible to use.
Shear behavior of fly ash reinforced concrete beam without shear reinforcement
Authors: Nasution A E , Kurniawan R , Thamrin R 
Published: September 2019

Abstract
An experimental study was carried out to discover the shear behavior of reinforced concrete beam (RCB) using fly ash (FA) as cement replacement material. Variation of FA composition that was used as the research variable were 10 %, 20 % and 30 % by cement mass. Each of the variations has two RCB specimens while two RCB specimens used normal concrete (non FA) as control beams. The beam was reinforced only in the longitudinal direction without shear reinforcement. The beam was tested by the static monotonically loading method. The results showed that the shear strength of RCB decreased by increasing the amount of FA.
Evidence for a Previously Unrecognized Species of Owlet-Nightjar
Authors: Pratt Thane K. 
Published: September 2019

Abstract
I studied the systematic relationships of the three large owlet-nightjars (Aegothelidae) to determine the taxonomic status of a fawn-colored lowland form currently classified as Aegotheles insignis tatei. I examined most of the existing specimens of A. i. insignis (n = 158) and A. crinifrons (n = 23) and all known specimens of A. i. tatei (n = 4). I also examined specimens of A. albertisi (n = 70), A. archboldi (n = 25), A. bennettii (n = 55), A. cristatus (n = 50), A. savesi (n = 1), and A. wallacii (n = 21). Aegotheles i. tatei was distinguishable from A. i. insignis and A. crinifrons by its small size and in seven plumage characters. Aegotheles i. tatei was further distinguishable from one or the other of these taxa by four additional characters. Unique among owlet-nightjars, A. i. tatei has the shortest tarsi, does not have recurved filamentous tips on its facial feathers, and has stiffer feathers on the auricular area and throat. My search of museums revealed two new specimens of A. i. tatei, expanding the known geographic range of this taxon 1,000 km eastward along the southern coast of Papua New Guinea from the upper Fly River to Nunumai, near the Ulamanu River. Unlike the montane A. i. insignis, A. i. tatei inhabits lowland forests where rivers emerge from foothills of the main cordillera. I propose that tatei be elevated to species status and that the name Starry Owlet-Nightjar be adopted based on the bird's markings. Aegotheles crinifrons, A. insignis, and A. tatei pass through a previously unrecognized but distinctive rufous juvenal plumage. These are the only owlet-nightjars known to exhibit this plumage, which calls for reexamination of generic limits within the Aegothelidae.
Seasonal, Age, and Sex-Related Variation in Fatty-Acid Composition of Depot Fat in Relation to Migration in Western Sandpipers
Authors: Egeler Oliver , Williams Tony D. 
Published: September 2019

AbstractThe composition of depot fat in Western Sandpipers (Calidris mauri) was dominated by C16 and C18 fatty acids (palmitate, 16:0; palmitoleate, 16:1; stearate, 18:0; oleate, 18:1), which together comprised 80 to 90% of all fatty acids analyzed. Significant seasonal variation occurred in the relative proportion of specific fatty acids and the ratio of saturated to unsaturated fatty acids in relation to the migratory cycle of the sandpipers. In adults of both sexes, the proportion of 16:0 and 18:0 fatty acids decreased from winter (December) to premigration (March) to spring migration (May), whereas the proportion of 16:1 and 18:1 fatty acids increased over these same periods. Consequently, total unsaturated fatty acids increased by 34% between the winter and premigratory phase, and by a further 22% between premigration and spring migration. Therefore, biochemical modification of adipose tissue in Western Sandpipers begins during the premigratory period in preparation for long-distance flight but continues as migration progresses, perhaps reflecting a training component of physiological modulation for migration. Juveniles showed similar changes to adults in the composition of their depot fat during the “premigratory” period, even though most juveniles do not undergo hyperphagia or rapid fattening at this wintering site. Potential prey species collected from a wintering site in Panama had a higher proportion of saturated fatty acids, less 16:1 and 18:1, and more 18:0 fatty acid compared with those from a migratory stopover site in British Columbia, paralleling the seasonal changes in depot fatty-acid composition observed in Western Sandpipers. However, the fact that Western Sandpipers show an increase in level of unsaturation and in the amounts of 16:1 and 18:1 fatty acids in their fat stores on the wintering ground prior to migration suggests that seasonal variation in fatty-acid composition is not entirely diet dependent.
Influence of Niche Overlap and Territoriality on Hybridization Between Hermit Warblers and Townsend's Warblers
Authors: Pearson Scott F. , Manuwal David A. 
Published: September 2019

AbstractHybrid zones between Townsend's Warblers (Dendroica townsendi) and Hermit Warblers (D. occidentalis) in the Pacific Northwest are narrow relative to estimated dispersal distances and appear to be moving, with Townsend's replacing Hermits. We examined whether the habitat-transition and parental-fitness asymmetry models can explain why these zones are narrow and moving by comparing habitat variables associated with warbler territories in the Washington Cascades hybrid zone. Habitat variables did not differ among phenotypes, suggesting that the habitat-transition model cannot explain the narrow and dynamic nature of this hybrid zone. Habitat characteristics of Hermit Warbler territories did not differ inside versus outside the hybrid zone, also suggesting that this zone is not associated with a region of habitat transition. The lack of difference in habitat use could be the result of comparing variables that are not important to pairing success. However, warblers tended to select territories on west-southwest aspects. South aspects in the southern Washington Cascades are dominated by Douglas fir (Pseudotsuga menziesii) and true fir, which is a habitat selected by female warblers when choosing among territories and males. The parental-fitness asymmetry model does not necessarily make predictions about habitat use within the hybrid zone but predicts the superiority of one parental species over the other. However, if significant overlap occurs in habitat use or niche (as in these warblers), then competition between parental species is likely to occur. To determine whether these species compete, we mapped 12 warbler territories and monitored an additional 94 territories throughout the breeding season and found that all males with neighbors compete for and hold exclusive territories. Thus, the pattern of habitat use and territoriality is consistent with the parental-fitness asymmetry model.