bluuebunny/crossref_metadata_2025_split huggingface dataset:
Diet composition and trophic niche similarities of engraulid fishes in Pabean bay, Indramayu, Indonesia
Authors: Syafei L S , Siregar R S , Rahardjo M F , Simanjuntak C P H 
Published: December 2019

Abstract
A study on the trophic ecology of fishes is one of the approaches to acquire a better understanding of fish feeding strategies, prey inclinations, niche competition and increase knowledge on the working of marine biological system. The present work aims to determine diet composition and trophic niche overlap among species of engraulid fishes in the coastal area of Pabean. Sampling was performed monthly from April 2016 to March 2017 and fishes were captured using gill nets and guiding barriers. During research period, seven species of engraulid were collected, namely Thryssa hamiltonii (with total length ranged from 47-186 mm), Thryssa mystax (53-151 mm), Thryssa kammalensis (66-112 mm), Thryssa setirostris (106-132 mm), Stolephorus indicus (54-133 mm), Stolephorus dubiosus (56-75 mm) and Stolephorus tri (66-91 mm). Prey of fishes were classified into four taxonomic groups i.e., Bacillariophyceae, Polychaeta, Crustacea and Pisces. Crustacea was the most consumed category (IRI>90%), recorded for all species of engraulid fishes, followed by Bacillariophyceae (<10%), polychaeta and fish juveniles (<5%). This finding indicates that all engraulid fishes in Pabean waters are crustasivore. Inter-specific feeding overlap was high, indicates that feeding competition among engraulid fishes tends to be high when food resources is decreased.
Pepsin activity from gastric of milkfish and catfish in Indonesian Waters
Authors: Nurhayati T , Ambarsari L , Nurilmala M , Abdullah A , Rakhmawati I A I , Yuniasih  
Published: December 2019

Abstract
Pepsin is the main protease enzyme in the gastric including the gastric of the fish. The enzyme has many benefits for both food and non-food. The purpose of this study was to determined the pepsin activity of the catfish and milkfish. The study was divided into 2 stages, namely pepsin extraction stage and pepsin characterization. The results showed that pepsin from milkfish and catfish can be extracted properly using tris-Cl buffer with the activity of 526.5 U/mL (catfish) and 397 U/mL (milkfish). The pepsin isolated from the gastric of catfish and milkfish can work well at a temperature range of 20-40°C and pH 1-3. Pepsin from the gastric of catfish had Km = 0.3333 mM and Vmax = 1666.6667 mmol/s. Pepsin from milkfish has Km = 0.091 and Vmax = 909,091 mmol/s.
Identification of active compounds from lindur root plants (Bruguiera gymnorrhiza) as α-glucosidase inhibitors
Authors: Dia S P S , Nurjanah  , Jacoeb A M 
Published: December 2019

AbstractLindur (Bruguiera gymnorrhiza) is a plant that contains bioactive sources for antioxidants and α-glucosidase inhibitors. The α-glucosidase inhibitors are inhibitors of the α-glucosidase enzyme involved in digestion in the intestine. This study aimed to determine and select the potential inhibitory activity of the α-glucosidase enzyme from the crude extract of lindur by in vitro. This research was carried out through several studies that involved multilevel extraction. testing α-glucosidase inhibitors from crude extracts of lindur root. Fractionated from active extracts of lindur used thin layer chromatography (TLC) & preparative thin layer chromatography (PTLC). and combined compositions bioactive from the most active fraction. The highest yield was obtained from root ethanol extract which was 4.68. Ethanol extract of stem and root bark had an activity of α-glucosidase enzyme inhibitors calculated by IC50 values 171.31 ppm and 153.07 ppm. The fractionation results used preparative (PTLC) showed 5 fractions in crude ethanol root extract. Fraction 1 with Rf 0.15 had the most potential activity of α-glucosidase enzyme inhibitors (161.05 ppm). Identification chemical composition used by Gas Chromatography Spectrometry (GC-MS) showed the composition contained in the fraction 1 of the root ethanol extract mostly (similar to> 90%) was hexadecanoic acid or palmitic acid and phenol.
Some consequences of unreported fishing on the results of simple fish stock assessment
Authors: Sondita M F A 
Published: December 2019

Abstract
Unreported fishing received less attention than illegal fishing but the later contributed the problem of data availability. Among various data needed for fish stock assessment, catch and fishing effort are popular for some preliminary analysis to describe annual trends of catch, fishing effort and catch per unit effort. Surplus production models can be used to determine the status of fish stock, maximum sustainable yield (MSY) and optimum annual fishing effort. Fisheries authorities then can determine some management measure promoting sustainability of the fisheries, such as total allowable catch. This study exercised some consequences of unreported fishing effort and catch data on the outputs of the assessment by a simulation with different levels of data using the model. The estimates of both MSY and optimum fishing effort were lower when catch and fishing effort were not fully reported. When the authority should firmly use the best available but limited data, their decision on the maximum annual catch and fishing effort will be more conservative. In contrast, their decision can be risky if over-estimated catch and fishing effort were used. If fishers expected fair levels of catch and fishing effort, the authorities can firmly ask them to provide data completely.
Evaluating the effectiveness of mangroves rehabilitation efforts by comparing the beta diversity of rehabilitated and natural mangroves
Authors: Rahmania R , Kepel T L , Arifin T , Yulius  
Published: December 2019

AbstractIndonesia has lost 30% of the area over the past two decades due to anthropogenic activities. To overcome this problem, mangrove rehabilitation-which is generally interpreted as mangrove planting program - become the most popular option. These efforts could enhance the quantitative function (increasing mangrove areas extent and number of trees planted), yet the quality functions (biodiversity and ecological function) remain unclear. This analysis was carried out simultaneously with medium to high-resolution satellite image analysis to differentiate mangrove canopy pattern of these sites. The results showed that beta diversity value of mangroves in rehabilitation sites was lower than mangroves in natural area, which was characterized in satellite imagery as more uniform canopy and finer texture. Rehabilitation efforts that are mostly done through monoculture, are unable to produce an equal mangrove ecosystem function as natural mangroves do. This paper aims to examine the effectiveness of rehabilitation efforts whether they can develop an equal ecological function as good as natural mangrove ecosystem, by comparing the difference of beta diversity in two study sites which representing the natural (north Sulawesi) and rehabilitated mangrove (West Bali).
Restructuring steak from flakes of yellowfin tuna meat using low salt microbial transglutaminase (MTGase)
Authors: Ardiansyah A , Sahubawa L , Ustadi  
Published: December 2019

Abstract
Restructuring of fish meat can be done by using fragments of by-product processing such as fillet, loin, and steak of yellowfin tuna. The binder agent that may be the most efficiently used in restructuring the product is microbial transglutaminase (MTGase). Salt is needed to optimize the binding process of the restructuring product. The objective of the study was to determine the effect of low salt MTGase concentration as a binding agent on the quality of restructured yellowfin tuna steak compared to commercial yellowfin tuna steak. Research was designed with completely randomized design using 5 treatments in the 1.5% salt concentration, namely 0%, 0.3%, 0.5%, 0.7%, and 0.9%. The analyzed parameters were proximate (water content, protein, fat, carbohydrate, and ash), texture, colour and water holding capacity. The sensory test was conducted to compare restructured products with commercial tuna steak. The results indicated that the best treatment to the addition of MTGase was 0.5% based on the physical properties of the product, the nutritional content and sensory test. In sensory, MTGase was able to maintain the colour (brightness) of the products as they were darker than the commercial tuna steak and improve the product’s texture (hardness) in the addition of 0.9% MTGase.
Assessing stock status of grey sharpnose shark (Rhizoprionodon oligolinx Springer, 1964) in Java Sea
Authors: Wijopriono  , Ernawati T 
Published: December 2019

Abstract
Increasing demand for shark products leads to over fishing of these species in many areas, damaging their population. Grey sharpnose shark (Rhizoprionodon oligolinx) is caught mostly by gillnet fleet in Java Sea. The objective of the study was to discuss the current stock condition of grey sharpnose shark in Java Sea. Research on shark resources has been conducted by placing enumerators at the main landing base in PPN Pekalongan. Biological parameters of R. oligolinx were estimated based on commercial landings data recorded by enumerators from 2014-2015. The growth parameters of grey sharpnose shark such as L∞, K, t

0
, values were 96.1 cm, 0.47 year−1, and -0.78 year, respectively. Moreover, total mortality rate (Z) were estimated at 1.82 year−1 with fishing mortality and natural mortality rates (F and M) were 1.04 year−1 and 0.78 year−1, respectively. Stock status of grey sharpnose shark in Java sea from view point of gill nets fisheries is still in the sustainable utilization status with biological reference point more than 30% SPR and level of exploitation rate (E) is 0.57.
Purification of chitosanase from Stenotrophomonas maltophilia KPU 2123 and Micromonospora sp. T5a1 for chitooligosacharide production
Authors: Patantis G , Zilda D S , Fawzya Y N , Chasanah E 
Published: December 2019

Abstract

Stenotrophomonas maltophilia KPU 2123 and Micromonospora sp. T5a1 are bacterial strains isolated from shrimp waste capable of hydrolyzing chitosan to produce chitooligosaccharides (COSs). Their COS products showed antimicrobial activity. The aim of this study was to purify chitosanase from those bacteria and used for COSs production. Chitosanase from both strains were produced using 0.5% colloidal chitin as inducer. The chitosanase was then purified by ultrafiltration, DEAE Sepharose ion exchange and Separacyl S-300 gel filtration chromatography. The specific activity and the yield of chitosanase KPU 2123 increased 2.35-fold and 30.90% after three steps of purifications, respectively, whereas chitosanase T5a1 increased 3.32-fold and 22.79%, respectively. The molecular weight of both chitosanases KPU 2123 and T5a1 were about 76 and 20 kDa, respectively. The COS products generated by chitosanase KPU 2123 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine, Tri-N-acetyl-D-glucosamine, Tetra-acetyl-D-glucosamine and Penta-N-acetyl-D-glucosamine while by chitosanase T5a1 contained N-acetyl-D-glucosamine, Di-N-acetyl-D-glucosamine. Based on their COS products, chitosanase KPU2123 can be categorized as endo-type chitosanase. Further study is needed to analysis the bioactivity of COSs obtained from the pure of chitosanases KPU 2123 and T5a1.
Ecofriendly land-based spiny lobster (Panulirus sp.) rearing with biofilter application in recirculating aquaculture system
Authors: Thesiana L , Adiyana K , Zulkarnain R , Moersidik S S , Gusniani I , Supriyono E 
Published: December 2019

Abstract
The aim of the study was to create water treatment units for ecofriendly landbased spiny lobster rearing. Recirculating aquaculture system (RAS) is widely used because it is more environmentally friendly. Water quality requirement for spiny lobster cultivation are DO>4 mg/L and ammonia (NH3) less than 0.1/mgL. Attachment growth biofilter with sponge media used for reducing ammonia. Hydraulic loading rate 200 m3 m−2day−1 was used to evaluate biofilter TAN removal. Ammonia (NH3) concentration during the study range between 0.006-0.02 mg/L, total ammonia nitrogen 0.0-0.26 mg/L and DO concentrations at 6.29-6.54 mg/L. Volumetric TAN removal average value during the 24-hour observation was 23.33 g TANm3day and lobster survival rate reach 91.89%. This water treatment unit comply water quality requirements for lobster cultivation, and also can be used for other fishery commodities by adjusting their capacity to meet specific water quality standard.
On variations in turbine runner dynamic behaviours observed within a given facility
Authors: Gagnon M , Nicolle J 
Published: December 2019

Abstract
When confronted with cracks or high stresses in turbine runners, we often wonder if the behaviour observed on one specific runner will be present on all other similar runners. In this case, we have a facility with 19 runners having the same blade geometry. In order to answer the question, we selected three runners for measurement campaigns. First, the runners were divided in groups using band length, materials and wicket gate geometries. We then examined two runners with different wicket gate geometries and were thus able to explain why one runner exhibited recurrent fatigue damage problems and not the other. However, even within a given group, significant reliability differences were found when comparing with a third runner. The observed data shows that an important turbine characteristic was overlooked. Our conclusions point toward eccentricities and imperfections in the discharge ring attributable to only the upper part of the labyrinth seal being refurbished in this facility. This may generate a significant imbalance in the force produced by the flow in the runner side chamber. The paper underscores the impact of such imbalance, which could be present in older refurbished facilities.
Two-way strongly coupled fluid-structure interaction simulations with OpenFOAM
Authors: Doulcet Benjamin , Devals Christophe , Nennemann Bernd , Gauthier Maxime , Guibault François , Trépanier Jean-Yves 
Published: December 2019

Abstract
Predicting fluid-structure interaction phenomena is an ongoing challenge in numerical simulations. While we look for fast algorithms to solve the equations, some problems need a high accuracy in order to correctly predict results. Hence, controlling every aspect of the algorithm gives the possibility to optimise specific parts, potentially leading to greater accuracy. Developing such a numerical methodology can be achieved on an open source software such as OpenFOAM.
Dissolved-gas influence on the Francis part-load oscillation
Authors: Dörfler P K 
Published: December 2019

Abstract
A forced oscillation of system pressure occurs when a Francis turbine operates at partial load, typically between 50-85% of best-efficiency flow. Its cause is the precession of the draft tube vortex; due to cavitation of the vortex, the oscillation may enter in resonance. Predicting such a resonance from reduced-scale model tests is a long-standing goal of hydraulic research. Key parameter controlling the natural frequency of the underlying eigenmode is the compressibility of the cavitation zone. With the vortex cavity at vapor pressure, the natural frequency would scale by the same factor as the runner speed, thus enabling simple resonance prediction based on the model test. Based on experimental evidence, the actual pressure inside the vortex cavity is higher than vapor pressure, and the non-condensable gas content has significant influence. Due to uncontrolled variation of cavity pressure, the natural frequency in model tests may deviate by as much as 30% under nominally identical conditions. A 1D mathematical model can represent the influence of non-condensable gas on the cavity volume and compliance; even quite moderate cavity pressures explain the observed discrepancies.
Recent developments in unsteady pipe flow experimentation at the University of Montenegro
Authors: Brđanin R , Karadžić U , Bergant A , Ilić J 
Published: December 2019

Abstract
This paper presents recent experimental results of pressure measurements during filling and emptying of a relatively small-scale pipeline at the University of Montenegro. Experimental setup for investigation of water hammer and its special effects (unsteady friction, cavitation, column separation, trapped air, fluid-structure interaction - FSI), and pipeline filling and emptying is installed at the Faculty of Mechanical Engineering. It consists of an upstream end high-pressurized tank, horizontal steel pipeline (total length: 55.37 m, inner diameter: 18 mm, pipe wall thickness: 2 mm), four valve units positioned along the pipeline including the end points, and a downstream end outflow tank. The setup was upgraded in 2018 with the installation of new piezoresistive pressure transducers and pipe displacement sensors as well as additional electro-pneumatically operated ball valve at the upstream end of the pipeline. The filling of an initially empty pipeline is performed by a sudden opening of the valve positioned at the high-pressurized tank filled with water. The pipeline emptying process is accomplished by high-pressurized air supplied from the air reservoir installed in the air supply line. The high-pressurized tank is closed, and the downstream end valve is opened. Experimental runs have been performed with different initial values of pressure in the upstream end high-pressurized tank (filling) and air supply line (emptying). Results of new pressure measurements are analyzed and commented, with a reference to the previous experiments presented at 6th IAHR WG Meeting in Ljubljana, 2015.
Tin (Sn) whisker growth from electroplated Sn finished
Authors: Hashim Aimi Noorliyana , Salleh Mohd Arif Anuar Mohd , Mokhtar Noor Zaimah Mohd , Idris Shahida 
Published: December 2019

Abstract
Electroplated tin (Sn)Limeited finishes are widely used in the electronics industry due to their excellent solderability, electrical conductivity and corrosion resistance. However, since prohibiting the use of lead (Pb) in electronics, the issue of tin (Sn) whisker has become one of the most imperative issues that need to be resolved. Moreover, with the increasing demand for electronics miniaturization, Sn whisker growth is a severe threat to the reliability of microelectronic device. This paper investigates the effect of electroplating current density (10, 30 and 50 mA/cm2) on whisker growth at room temperature. A simple micro- indentation test was used to accelerate continuously the growth of Sn whisker at room temperature storage for 24 h. Morphology analysis of Sn whisker growth was done using scanning electron microscope (SEM) and image-J Software. Axial length of the Sn whisker was calculated by using JEDEC Standards (JESD22-A121A).
Interfacial reactions between different Sn-based lead- free solder alloys and CuNi substrates
Authors: Razak Nurul Razliana Abdul , Tan Xin Fu , McDonald Stuart D. , Nogita Kazuhiro 
Published: December 2019

Abstract
The effect of the presence of Ni in Cu substrates on the interface reaction during soldering and the growth of Sn-Cu intermetallic compounds (IMCs) was studied. The study involved reflow soldering of Sn-0.7Cu, Sn- 3Ag-0.5Cu and Sn-0.7Cu-0.05Ni lead-free solders on pure Cu and Cu-6Ni substrates with holding times of 5, 10 and 15 minutes at 232 °C. The presence of 6 wt% Ni in the Cu substrate strongly affects the microstructural evolution and the growth of the IMCs. The presence of Ni in the substrate significantly increased the overall thickness of the (Cu,Ni)6Sn5 layer while suppressing the formation of the Cu3Sn layer. The thickness of the (Cu,Ni)6Sn5 layer increased with reflow time for both Cu and Cu-6Ni substrate.
Recovery of tin from copper dross by acid leaching
Authors: Jabit Nurul Ain , Ismail Suhaina , Azhar Muhammad Alif Noor 
Published: December 2019

Abstract
Copper dross(CD) is a waste product formed during copper doping where sulphur was added to the tin metal during refining process to remove copper in the form of copper sulphide. CD was found to contain significant amount of tin and other valuable metal such as copper that could be trapped during copper doping process. The main objective of this work is to assess the potential of CD as a secondary resource for tin product and the applicability of hydrometallurgical process to extract tin and copper. Two main parts involves in this work are CD characterization and recovery of tin by acid leaching. From elemental composition analysis by XRF, in CD sample, amount of SnO2 present is about 63% followed by SO3 with 14%, Fe2O3 is 9% and CuO with 2.5%. Cassiterite and magnetite is the main phases found by XRD analysis. From the leaching study, it was found that almost 60% of tin has been dissolved in acid solution at condition of 80 °C, 2 M HCl with 8 hours leaching time.
Graphitization damage on seamless steel tube of pressurized closed-loop of steam boiler
Authors: Hayazi Nur Farhana , Shamsudin Shaiful Rizam , Wardan Rajaselan , Sanusi Mohd Syazwan Muhamad , Zainal Farah Farhana 
Published: December 2019

Abstract
The pressurized closed-loop of steam boiler has been in operation for five years has experienced leakage problems at the bottom of the reducer and at the center of the tube on weldment. The metallographic analysis found that the leakage was due to the degradation of microstructure as a result of long-term overheating. The degraded microstructure of the tube boiler material dominated by graphitization. The graphitization normally applicable at 450°C, but with high-pressure water flow (90 bar) in the combination of internal stress on the tube material due to the welding process as well as the formation of the reducer, making the boiler operating temperature is sufficient to produce graphitization. The leakage occurred when the chain and accumulated graphitization happen because the cavities that covered the graphite facilitates the cracking propagation due to the presence of stresses.
Influence of filler content and mixing time on the properties and morphology of kenaf/polyurethane foam composites
Authors: Soberi Nur Suhaili Mohd , Rozyanty A. R , Zainuddin Firuz , Osman A.F 
Published: December 2019

AbstractKenaf/polyurethane foam composites were prepared at percentage of 2, 4, 6 and 8 wt% of kenaf fiber. Free rising polyurethane foam was prepared at constant (NCO/OH) ratio 1.5:2, while water was used as blowing agent. The mixture was stirred at 400 rpm using mixing times of 20 and 25 seconds. Rise time and hardness of the composites was determined. From the results obtained, rise time and hardness of polyurethane foam composites were reduced at 25s mixing time. However, as kenaf core fiber increase, the rise time decreased and the hardness of the foam composite increased. The Scanning Electron Microscopy (SEM) analysis evidenced the presence of regular cell shape and uniform cell size in the kenaf/polyurethane foam composites. The findings indicate the potential of using kenaf fiber to enhance the properties of the polyurethane foam.