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The bipolar plate acts as a critical element in the Proton Exchange Membrane Fuel Cell (PEMFC) system, constituting 60-80% of the total weight of a PEMFC stack. In recent years, there has been a growing interest in exploring aluminum alloys for bipolar plates. The only crucial challenge for aluminum bipolar plates is their inferior corrosion resistance in the acid environment of PEMFC. This study aims to enhance the corrosion resistance of AA5052 plates by AAO/Ni-Ag coating for PEMFC application. The fabrication of AAO was carried out by anodizing process in 16% H2SO4 at 25, 0, and -25°C with the current densities of 10 and 20 A/dm2 for 30 minutes. Subsequently, the electrodeposition of Ni-Ag on anodized AA5052 was conducted in a solution containing 240 g/L NiSO4⋅6H2O and 7.5 g/L AgNO3 with the current density of 2 A/dm2 at room temperature for 15 minutes. The corrosion properties of the integrated coating were investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic test in a solution of 0.5M H2SO4 with 2 ppm HF at ambient temperature. The findings demonstrated that the incorporation of a protective layer on AA5052 substrates substantially enhanced the ability of bipolar plates to withstand corrosion in the fuel cell's operational conditions in comparison to substrates without any coating. The substrate, when subjected to an anodizing current density of 20 A/dm2 and a temperature of -25°C, exhibited superior performance. Its corrosion rate was 20 times lower compared to an uncoated substrate, and the Nyquist Curves displayed a larger curve and higher impedance value. [ABSTRACT FROM AUTHOR]

Malacca Strait Fisheries is a multi-species coastal and offshore fishery with diverse types of fishing gear and fleet structures. The area is one of the potential waters to provide fish resources for human consumption. Squid is one of the typical target species caught using certain types of fishing gear. The annual squid landing in 2020 was approximately 22,800 tons, with a gross value of 820 billion IDR. The squid landed in Aceh province totalled 835 tons, with North Sumatra 21,703 tons. Time series analysis was performed using the landing statistical data of squid (multi-species) from 1977 (720 tons) to the present day. The results indicated that the landing in 2020 had a relatively high catch rate. The proportion of squid to total catch was shifted from < 0.2% (1977) to 4% (2020). The diversity of fishing gear used was high and was predominately by squid angling and small pelagic seiners, with fleet sizes varying from < 5 GT to 125 GT. This paper describes the early stages of exploitation indicators for multi-gear squid fishery in the area. Determining the susceptibility of overfishing, challenges, and threats to the marine ecosystem is challenging. The result would support the data-limited fisheries approach to describe the subsequent topics on the dynamics of squid fisheries concerning long-term benefits for coastal communities' livelihood on the east coast of North Sumatra. [ABSTRACT FROM AUTHOR]

In this paper, we aim to examine and compare some numerical schemes for the fractional-order logistic growth model with respect to the Caputo-Fabrizio operator. We provide some numerical schemes of the solution using linear interpolation (LLI), three-point centered interpolation (LCI), three-point backward interpolation (LBI), and three-point extrapolation (LE), which are Lagrange-based approximations. An LCI-based scheme is a new scheme, and the other schemes are derived from previous studies. We perform all numerical schemes to model for different values of step sizes and derivative orders and then compare them to the analytical solution. The analytical solution of the model was obtained via the corresponding fractional-order integral. We determine the root mean square error (RMSE) for each numerical scheme. The LBI-based scheme generally has the best performance in all conditions, with the smallest RMSE. The LE-based scheme has good performance for small steps. However, it is disreputable for its quite large step size, even providing spikes and an unsmooth solution. This leads to a change in the convergence of solutions. Finally, two other schemes have consistent performance in all conditions of step size, where the LCI-based scheme is slightly better than the LLI-based scheme. For an approximation of the analytical solution, we suggest using the LBI-based scheme for the best results. [ABSTRACT FROM AUTHOR]

Wind is a renewable energy that is available in abundance but the usage is still limited. The limited use of this energy is because wind is not always available at all times, especially in urban areas with densely populated settlements. An innovation is needed in the utilization of wind energy, one of which is an Archimedes wind turbine. This turbine is a horizontal axis type wind turbine with the blades follow spiral form. Unlike horizontal wind turbines which use only lift to rotate the blades, Archimedes turbines use both lift and drag. The objective of this research was to design an Archimedes wind turbine through the Solidworks software simulation to determine the aerodynamic characteristics of the turbine based on variations in angular velocity of turbine. The aerodynamic characteristics is power coefficient and Tip Speed Ratio (TSR) determined using blade parameters are radius, pitch, opening angle and angle of attack. The wind speed using the average wind speed of Central Java, which is 3 m/s. Design and simulation using Solidworks. The conclusion that can be drawn from this study is maximum Cp produced by the Archimedes turbine in this study was 0.292, at a TSR of 1.6. The Cp in this study was lower than the American multi-blade type, but it had a 50% greater TSR. A high TSR value indicates that low wind velocity produce high turbine rotations. So it can be said that the Archimedes turbine can be used and efficient for areas with low wind speeds. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is synthesized from extract of pineapple peel and Acetobacter xylinum as fermentation bacteria. This study aims to investigate the influence of graphene concentration on the morphology and crystalinity in bacterial nanocellulose (BNC) nanocomposites. To obtain bacterial nanocellulose (BNC), the previously manufactured pellicle BC was homogenized using a high-speed blender and a high-pressure homogenizer (HPH). Bacterial nanocellulose was combined with different concentrations of graphene (0.25, 0.5, and 1%), and then put into an ultrasonic homogenizer. Then, BNC-graphene solution was poured into a glass mold laminated with aluminium foil, and it was dried in an oven for 14 hours, 80°C. Scanning electron microscopy (SEM) was used to observe the morphology of nanocomposites membrane. X-Ray Diffraction is used to investigate the crystallinity of nanocomposites membrane. The structure of BNC-graphene nanocomposites membrane become more compact, according to the synthesized results. A few peaks at 2θ of 14.5°, 16.6°, 22.7° are seen in the XRD analysis, as well as a graphene diffraction pattern peak at 2θ of 13.7°. Nanocomposites membrane's crystallinity was reduced after graphene was added when compared to nanocomposites membrane without graphene. [ABSTRACT FROM AUTHOR]

Bacterial nanocellulose (BNC) composite membrane reinforced with titanium dioxide (TiO2) and addition polyethylene glycol (PEG) were analyzed in the study. Bacterial cellulose (BC) pellicle from pineapple peel waste extract. BC pellicle was cleaned with 1% NaOH. BC was mashed with a blender and carried out a high-pressure homogenizer (HPH) method of 5 cycles at a pressure of 150 bar, filtered through a vacuum filter. Composite membrane synthesized 10 grams BNC, 1% TiO2, and 1% PEG. All were mixed and dried in an oven for 14 hours at 80℃. Morphology and crystallinity were analyzed. SEM morphology of BNC membrane added with PEG made fibers look large because they were coated with PEG. BNC/ TiO2 added with PEG surfactant was able to disperse TiO2 evenly. Results of crystallinity membrane contained 4 diffraction peaks angle 2θ: 14.5°,16.8°, 22.6°, and 25.2°. Diffraction peaks BNC with BNC/PEG increase because PEG is a plasticizer making diffraction peaks larger. 1% TiO2 nanoparticles with the addition of 1% PEG caused crystallinity value and crystallinity index to decrease because the low interaction of PEG with TiO2 is hydrophobic, TiO2 is evenly dispersed in an aqueous solution and evenly distributed on the BNC matrix. [ABSTRACT FROM AUTHOR]

Bacterial Cellulose (BC) offers unique physical qualities such as high purity, crystallinity, and mechanical strength, as well as a high-water absorption capacity. Pineapple peel may be utilized as a source of cellulose, which is employed in a variety of applications. To improve the combination of BC and TiO2, TiO2 must be added, which affects the production of the cellulose membrane. The morphology of the membrane was studied using scanning electron microscopy (SEM). The membrane structure was studied using X-Ray Diffraction. SEM micrographs revealed that the control concentration increased the number of pores and had a small pore size of 81 nm, whereas the TiO2 concentration decreased the pore size. This drop is connected to the concentration increase. An XRD examination reveals the appearance of three peaks, the first at 14.12°, the second at 16.80°, and the third at 22.5°. The crystallinity index (Cl) and degree of crystallinity (Cr) increased with the addition of the specified concentration of TiO2, with the crystallinity index (CI) ranging from 66.8% to 76.1% and the degree of crystallinity (Cr) ranging from 50.3% to 68.6%. [ABSTRACT FROM AUTHOR]

The Cantang Grouper (Epinephelus fuscoguttatus-lanceoulatus) is a mating of the female Tiger Grouper fish (Epinephelus fuscoguttatus) and the male Kertang grouper fish (Epinephelus lanceoulatus). However, in farming activities, the Cantang Grouper fish can be affected by a VNN infection. One way to deal with the VNN infection is by giving recombinant nano-vaccine from the microalga Chlorella Vulgaris. This study aims to determine the effect of recombinant nano-vaccine administration of the microalgae Chlorella Vulgaris on the growth of the fish weight, length, and eye tissue in the Cantang grouper fish (Epinephelus fuscoguttatus lanceolatus) infected with Viral Nervous Necrosis (VNN). The method used in this study is experimental. The test results showed that the administration of the recombinant C. vulgaris (p-PerCv) vaccine affected the growth in length and weight of the Cantang grouper, this was because the growth in length and weight of its from the treatment group was significantly different from the control group (0.039<0.05). Known by the ANOVA test and also has a different effect on the level of damage to eye tissue both damage to hypertrophy, vacuolization, and necrosis. The results of the Tukey test showed that the treatment that had a significant effect was the T1 treatment (treatment of healthy fish +33l of recombinant C. vulgaris vaccine (p-PerCv) +8.5l of Chitosan nanoparticles). [ABSTRACT FROM AUTHOR]

Chemical treatment is a standard method to improve natural fiber properties. Treatment using a chemical agent like Silane as Coupling Agent and CTAB (Cetyl Trimethyl Ammonium Bromide) as a surfactant can improve the natural fiber properties. The current study aims to observe the fiber surface morphology and obtain the mechanical properties of Sansevieria cylindrica fiber after being treated with a silane coupling agent and surfactant CTAB. The research was conducted by chemical treatment using Silane 5.0% and CTAB 5.0% on S.cylindrica fiber extracted from about a year and lengths up to 110 cm. The tensile test was performed using a single fiber tensile test, and the surface morphology was observed under Scanning Electron Microscopy (SEM). The results indicate that adding 5.0% silane coupling agent results in fiber strength of 281.5 MPa, elongation of 8.92%, and elastic modulus of 3.37 GPa. The addition of CTAB of 5.0% results in fiber strength of 237.4 MPa, elongation of 8.92%, and elastic modulus of 3.37 GPa. Increasing these properties has resulted from the bonding forming of silanols with hydroxyl groups of fiber. The morphology of the fiber surface shows a rough surface caused by removing impurities over the surface for the treatment of both coupling agents and CTAB. [ABSTRACT FROM AUTHOR]

Producing cellulose from agricultural waste has the potential to lessen the industry's negative effect on the environment while also bringing about significant practical benefits. The waste from processing pineapples in Indonesia has significant potential for use in the production of cellulose acetate based on bacterial cellulose, and the country is a major exporter of processed pineapples. The purpose of this research is to characterise cellulose acetate made from pineapple peel residue. Bacterial cellulose was fermented using pineapple peel extract in this study. To standardise the size of the nanocellulose produced by bacteria, a high-pressure homogenization method was used. Cellulose acetate was made by an esterification method. Scanning electron microscopy, Fourier transform infrared analysis, and X-ray diffraction were used to decipher the findings. According to the study, the primary structure of cellulose was determined to be at the 22-degree diffraction angle peak. At the maximum diffraction angles of 14 and 16 degrees, there was a minor shift in the cellulose structure. Bacterial cellulose's crystallinity improved from 72.5% to 75.9% after being converted to cellulose acetate. Several peak changes, as determined by functional group analysis, pointed to a modification in the membrane's functional group. The membrane's surface morphology also shifts, becoming more smooth and glossy like cellulose acetate. [ABSTRACT FROM AUTHOR]

Polylactic Acid (PLA) is a popular material for 3D printing. PLA has the advantage of being biodegradable and derived from renewable resources. This study aims to determine the characteristic of recycled PLA extruded at various screw speeds. The extrusion process used a twin-screw extruder with screw speed as an independent variable consisting of 4 different screw speeds: 50 rpm, 60 rpm, 70 rpm, and 80 rpm, while the pulling speed and temperature of extrusion as control variables. The dependent variables are cross-sectional area, tensile strength and modulus elasticity obtained from tensile tests, fracture morphology observed using SEM, and structure observed using XRD. Results show the average cross-sectional area of filament increases along with higher screw speed. The overall tensile strength graph shows an increase in the average tensile strength of filament as screw speed increases, except for a speed of 70 rpm, where there is a decrease. The elastic modulus graph shows an unstable increase caused by flow instability. The fracture morphology of the filament gets rougher and more fibrous as the screw speed increases. XRD analysis shows that recycled PLA filament indicates peaks at 2θ=18° to 20.5° in 4 variables and that different screw speeds do not change the crystal structure of PLA. [ABSTRACT FROM AUTHOR]

Polylactic acid is an aliphatic polyester used as an environmentally friendly packaging application. The advantages of PLA are that it is easy to decompose and renewable and is made from renewable natural resources. Therefore, the material is extruded at different barrel temperatures to determine the effect of increasing the barrel temperature. This study aims to determine the changes in the mechanical properties, morphology, and structure of the polylactic acid filament by extrusion process with different barrel temperatures in the heating zone. Recycling is done in the third extrusion with different barrel temperature zone variations. Investigation of mechanical properties was determined by static tensile test, fracture morphology analysis of tensile test using SEM. The tensile test results show a gradual increase in tensile strength at each increase in the barrel temperature zone, from 60.48 MPa to an increase of 66.71 MPa, but at high barrel temperatures, the tensile strength decreases to 60.74 MPa. Morphological analysis of the tensile test fracture samples showed morphological changes, where morphological defects in the form of fibrous, voids, and scaly appeared after increasing the barrel temperature. Therefore, the barrel temperature parameter is not recommended to exceed 200℃ during the extrusion process. [ABSTRACT FROM AUTHOR]

In this study, the open-cell aluminium (Al) foam was fabricated through the melting route, utilizing vacuum casting. The different contents of fly ash particles were homogeneously added into the melt for the alloy reinforcement. The < 5 mm silica gel (SiO2) particles were filled into the mold cavity for the space holder during the foam casting. Afterward, the compressive test was performed on the foam samples by utilizing a universal testing machine under a constant strain rate of 1 mm/min. The addition of a higher amount of fly ash particles shifted the yield strength into a greater value. In parallel, the elastic modulus was also higher when more fly ash content is used in Al foam reinforcement. On the other hand, the maximum strength at 60 % strain decreased after 2.5 % fly ash addition and subsequently rose by further content of reinforcement. These phenomena are strongly related to the porosity and microstructural state of the fabricated foam formed after SiO2 removal. The results indicate that adding a certain amount of fly ash can modify the compressive properties of Al foam by acting as dispersive strengthening particles and withstand the cellular structure from early deformation during loading. [ABSTRACT FROM AUTHOR]

Crack analysis on coil spring is intended to simulate stress, fatigue life, SIF mode I, II, J-Integral, and fatigue crack growth rate. Simulations were carried out using the Ansys Static Structural approach. The material used was tested for its composition and obtained SAE 9260 steel material is. The simulation results in conditions without crack show that the stress concentration point occurs in the 2nd coil according to the location of the coil spring fracture with an equivalent value of von misses 1236.1 MPa below the ultimate tensile strength value of SAE 9260 material. The results of the stress intensity factor value show that mode II shows the highest value was KII=171.11 MPa mm , compared to the value of KI=97.175 MPa mm . This is following the analysis of the number of cycles and the fatigue crack growth rate in mode II which has a lower number of cycles of 97500 cycles compared to mode I which is 677700 cycles, while in mode II it has a critical crack size value of 10.28 mm followed by a drastic decrease in strength. The maximum value of J-Integral for the given crack is 0.33962 mJ/mm2 which is located at the end of the crack. [ABSTRACT FROM AUTHOR]

A Balinese script is one of the cultural relics of our ancestors and can be found in palm leaves. However, today Balinese script is abandoned along with the increasing use of the Roman script. Some efforts are needed for continuous socialization by developing the Balinese script learning media. We proposed the Balinese script identification using a machine learning approach. The backpropagation neural network algorithm is applied to create a predictive model recognizing Balinese scripts. Our study used 1001 Balinese character images extracted with the intensity of character algorithm, mark direction, and length and width of the character images methods. The result is promising. The training data accuracy is 90.31%, and the single testing data accuracy is 94%. The predictive model result shows the opportunity to develop a transliteration of Balinese script apps using the machine learning technique. [ABSTRACT FROM AUTHOR]

In this study, we developed a new fuzzy logic-based convolution layer on a two-dimensional Convolutional Neural Network (2D-CNN). This innovation aims to enhance the ability of CNN in recognizing colors. We experimented on P3Net, which is a 2D-CNN model that is used to predict photosynthetic pigment content in plant leaves in real time and non-destructive manner. The P3Net is designed to be able to predict three main photosynthetic pigment content (chlorophyll, carotenoid, and anthocyanin) based on the leaves color. The leaf colors were captured in the form of an RGB image and the image was used as the CNN input. We compare the performance of P3Net with and without the fuzzy logic-based convolution layer. It was revealed that the new form of convolution layer could significantly improve the P3Net performance. [ABSTRACT FROM AUTHOR]

Floods in Indonesia are often triggered by heavy rainfall with a long duration. Such heavy rainfall was influenced by several factors include seasons, Madden-Julian oscillation (MJO), and La Nina. The number of flood events in Indonesia in term of seasons, MJO, and La Nina has been observed from the Indonesian National Board for Disaster Management (BNPB) data from 2008 to 2020. Flood events in Indonesia during the 13-year observation showed the increase of annual trend in accordance with the global disasters trend. Floods events showed a significant seasonal variation with maximum number of occurence during January and February and minimum during August, coincided with the monthly rainfall pattern concerning the monsoon seasons in Indonesia. Furthermore, the MJO strongly modulated the number of flooding in Indonesia, where the flood occurence during strong MJO is more than twofold compared to weak MJO. The peak number of flood events during strong MJO was observed in 3, 4, 5 phases. In addition, La Nina modulated the number of flood events more significantly in the wet season, while in the dry season, La Nina effect was not significant compared to seasonal variation. [ABSTRACT FROM AUTHOR]

The process of industrial development is always dynamic, so it must have a high commitment so that companies in the industrialization process should be oriented toward customer desires. A reliable product planning design must maintain quality standards from the beginning of the process to the finished product so that the product unit is still in a good category when it reaches the customer because it is a major part that sustainability can be maintained consistently. Isolation machine engineering is carried out through Six Sigma, an overall approach to improve quality through the DMAIC method (Define, Measure, Analyze, Improve, and Control). At the Define stage using the Pareto diagram, the highest product scrap is Pure Cu 51.70%, the measuring stage obtained a sigma value of 3.14, and the Analyze stage uses a hypothesis test on vital factors so that the tub-Jig Printing Roll Single is obtained with the Improve stage which is carried out with a replacement of tub-Jig Printing Roll Double obtained a sigma value of 3.99 with efficiency 84.38% and at the control, stage using SPC (Statistical Process Control) so that the product looks in a good control chart. [ABSTRACT FROM AUTHOR]

Today using of ICT in the field of massive education is implemented. The research was conducted not only in the field of ICT learning but also science learning. This study aims for mapping digital literacy research in science learning. The goal is not only to map the research that has been done but to provide an overview for conducting research in the field of digital literacy in the future. The method used is bibliometric analysis assisted by VOSviewer program. The analyzed documents were collected from the Scopus database with the keywords "Digital Literacy", "Science Learning" and "Science Education". The data obtained were 60 documents which were then limited by document type journals and conference proceedings and used English. The results of the limitation were collected as many as 40 documents which were then analyzed. The findings obtained are that digital literacy is related to preparation in learning and competency achievement in the 21st century. In addition, teachers as teachers must have good digital literacy skills. The findings show that research in the field of digital literacy will continue to grow over time. [ABSTRACT FROM AUTHOR]

This study aims to determine the scientific attitude of junior high school students on the experimental in respiratory system of physics material. This research is a Research and Development (R and D) type. The development model used contains procedures from define, design, develop, and disseminate. The data collection technique was carried out using a scientific attitude questionnaire. The scientific attitude questionnaire contains 11 positive and negative questions. The questionnaire was prepared using a Likert scale with the answers TS (Disagree), KS (Disagree), S (Agree) and SS (Strongly Agree). The sample was selected using purposive sampling method, with a total of 10 students of class VIII SMP Negeri 1 Mantewe. Based on the research, results each aspect of scientific attitude are 79.83% for curiosity in a good category, 85.63% for Open-mindedness in a very good category and the last 80% for Honesty in a good category. That can conclude that all percentage for scientific attitude of students is 81.82% in the good category. [ABSTRACT FROM AUTHOR]

Osmosis membranes have been widely used in industries for water purification, wastewater treatment, and biomedical applications. However, the current membranes still have some drawbacks, such as water flow resistance and vulnerability to fouling. Therefore, the development of more efficient and durable osmosis membranes is highly necessary. In this research, the researchers used bacterial nanocellulose extracted from Sargassum sp. as a material for producing more efficient osmosis membranes. The methods used in this study were experiments with two treatments: (1) control, and (2) Bacterial cellulose with a concentration of 1.0 wt% CuO nanoparticles. The nanocellulose was produced using a high-pressure homogenizer, followed by the synthesis of acetate nanocellulose and characterization of the nanocomposite membrane functionalized with CuO nanoparticles. The membranes were characterized using FTIR and XRD analysis. Bacterial cellulose from seaweed was successfully formed with a thickness of 1-3 cm. The results of the characterization analysis showed that the formed bacterial cellulose belonged to Cellulose type I with a crystalline degree ranging from 88.7% to 85.7%. The dry osmosis membranes were analyzed based on their functional groups using FTIR. The analysis revealed changes in transmittance at the peaks of O-H at wavenumbers 3122-3414 and Cu-O at wavenumber 424-673, resulting from the addition of CuO nanoparticles and causing changes in the value of the O-H bond in bacterial cellulose. [ABSTRACT FROM AUTHOR]

Bacterial cellulose (BC) is a natural polymer produced from microorganisms with characteristics, such as a fibrous with porous structure, impressive mechanical properties, and high purity. The synthesis of BC nanocomposites reinforced by ZnO nanoparticles has been applied to increase their properties. The study aims to identify the structure of BC nanocomposites after being reinforced by ZnO nanoparticles. The methods included BC synthesis using pineapple peel extract in static fermentation for 10 days, the alkalization procedure, and defibrillation of Bacterial Nanocellulose (BNC) by high-pressure homogenizer. ZnO was added as a reinforcement with concentrations of 2.5%, 5.0%, and 7.5%, sonicated and dried in an oven at 60oC for 20 hours. BNC/ZnO nanocomposite was characterized using X-ray diffraction. This work shows that membrane BC has peaks at 18°, 22°, and 26°. After the addition of ZnO, the dominant peak is obtained at a diffraction angle of 14°, 16°, 22°, and 26°, and the amount of peak is increased. The addition of ZnO does not affect the crystal size of the membrane, but it affects the crystalization of BC, which is the addition of 7.5% ZnO maximizes crystallinity until 87.45%. In the future, this membrane will be developed as membrane filtration for wastewater treatment. [ABSTRACT FROM AUTHOR]

Styrene is a plastic-type that is used as a heat-insulating material for buildings with properties difficult to be degraded, so that, this plastic should be reduced in utilization with an alternative biofoam. This study aims to present the influence of ZnO reinforcement on morphology and strength of cassava starch-based biofoam. The experiment started with biofoam synthesis using baking methods method. Biofoam made of cassava starch containing the ZnO of 0%, 3%, 6%, 9%. The resulting biofoam was observed using a scanning electron microscope and tensile test. The result indicates that the morphology of biofoam without the addition of ZnO had cavities with thick inter-cavity walls, while biofoam with variations of the addition of 3%, 6%, and 9% ZnO formed relatively the same cavities with thinner inter-cavity walls when compared to biofoam without ZnO addition. The highest strength value occurred in biofoam with the addition of 6% ZnO resulting in an average tensile strength of 0.9283 MPa. Nonetheless, when the ZnO content exceeded 6%, as demonstrated by the addition of 9% ZnO, the tensile strength of the biofoam declined to 0.7544 MPa. [ABSTRACT FROM AUTHOR]

The strength of 3D printed part is an important factor that must be considered before carrying out a product design. The purpose of this research is to observe the surface quality and tensile strength of 3D printed part that is reinforced by epoxy resin. The specimen models were designed according to ASTM D3039 standards and printed using a 3D printer device. During the printing process, the layer height of deposit layer was varied into three different types while the main material used as a base material PLA. Furthermore, the specimens were divided into two categories, specimens with coating of resin polymer and without any coating. The coating process was conducted to the test specimens using a vacuum bagging technique by utilizing a vacuum pump as an air suction device. The specimen without any coating process were directly surface roughness test and perform tensile test directly. Based on the test results, lowest of surface roughness was occurred on specimen with resin coating. However, the highest tensile strength was showed by specimens without any surface coating. Although the addition of resin polymer shows a significant effect, but the layer height is not too significant. [ABSTRACT FROM AUTHOR]

Super Intensive white shrimp culture has developed well but has consequences for the waste produced, which is expected to be beneficial for the growth of mangrove seedlings as coastal ecosystem plants. The study aimed to determine the effect of intensive white leg shrimp culture waste on the performance of Rhizophora sp. mangrove seedlings. This research was conducted at the Experimental Pond Installation of Research Institute for Coastal Aquaculture and Fisheries Extension in Marana, Maros, from January to July 2019. The container used was a glass drink volume of 220 mL. This study was designed with two treatments, namely treatment A=wastewater treatment plant sediment 30%+coastal soil 70% and treatment B=100% coastal soil, each replicated three times, so there were six units of beds measuring 1x5 m containing 560 seedlings. The height of the mangrove seedlings used in treatments A and B were 627.16±12.60 and 660.50±2.97 mm, respectively, which were taken from the Tongke-tongke beach area in Sinjai Regency. Each mangrove seedling was planted in media with a 5-7 cm depth in drinking water glasses. Mangrove seedlings were placed in beds as experimental units and maintained for three months. The results obtained from this study showed that the increase in height in treatments A and B were 126.9±12.60 and 124.2±2.92 mm; survival rate 89.28±0.07 and 88.63±0.50%; the daily growth rates were 1.36±0.21 and 1.29±0.05%/day, and the plant sturdiness values were 4.51±0.05 and 4.63±0.05, respectively. [ABSTRACT FROM AUTHOR]

The purpose of this study is to assess the species composition and individual abundance of plankton in polyculture ponds in Maros Regency, South Sulawesi Province, utilizing eight plots of 2.500 m2 ponds. As treatments, white shrimp stocked at a density of 50,000 shrimp/hectare (A), white shrimp stocked at a density of 50,000 shrimp/hectare plus Larasati tilapia (1600 fish/ hectare) (B), white shrimp stocked at a density of 50,000 shrimp/hectare plus Larasati tilapia (1600 fish/hectare) plus seaweed Gracilaria sp (2000 kg/ha) (C), and Larasati tilapia (1600 fish/hectare) (D). Each treatment consisted of two replications and a maintenance period of 98 days. Every two weeks, plankton observations were made. The plankton was collected and kept in 1 Lugol solution, and the species were identified using a microscope and cell counting techniques. The acquired data on plankton condition were collated and examined in analyzed descriptively. The results showed that the highest number of phytoplankton species was achieved in treatment A (15 genera), followed by treatment B (9 genera), treatment C (9 genera), and treatment D (7 genera). While the highest number of zooplankton genera was obtained in treatment A (9 genera), then treatment B (9 genera), following treatment C (6 genera) and the lowest in treatment D (4 genera). The highest abundance of individual phytoplankton and zooplankton was found in treatment A, ranging from 115-2399 in /L and 34-3977 in/L, respectively. The plankton diversity index (H') varied between 0.7349-1.2134 in the ponds, the uniformity index (E) varied between 0.5348-0.9645, and the dominance index (D) varied between 0.4065-0.5370. [ABSTRACT FROM AUTHOR]

Research on the relationship between air quality, economic development, population growth, and energy consumption has been conducted in newly industrialized countries (NICs). It is necessary to analyze further the role of this variable in ASEAN countries in reducing environmental degradation. This study aims to analyze the interaction patterns of the causal relationship between air quality, economic growth, urbanization, and international commitments. The study was conducted in 5 central ASEAN countries from 1990 to 2014. Data were analyzed using the Panel Vector Error Correction Model (Panel VECM). The findings show a long-run relationship between urbanization and air quality variables. The bidirectional panel causality exists on urbanization and a unidirectional causality panel on air quality to economic growth. Mitigation strategies are needed to overcome the degradation in air quality. [ABSTRACT FROM AUTHOR]

Tirtomulyo village is one of the villages located in Plantungan, Kendal. The village of Tirtomulyo is located in a mountainous area. These geographical conditions make Tirtomulyo village has potential in the development of nature-based tourism, traditional cultural tourism, livestock tourism, and agricultural tourism. In this village has also formed a community-based tourism called Pokdarwis Gemilang. Pokdarwis has formed a website Barcode Tani dan Ternak (Bartander) of barcode agriculture and livestock. Bartander is one of the IoT (Internet of Things) based education programs developed to become attractiveness as one way of learning online and offline using digital literacy. Student organizations together with BUMDes Tirtomanunggal create Smart BUMDes application. Smart BUMDes is a BUMDes application that contains BUMDes business units, in this case tourist units that play a role in the branding and promotion of tourist villages. This research aims to examine community involvement in developing tourist villages through Bartander websites that are integrated with Smart BUMDes applications. To integrate the Bartander Website into Smart BUMDes, it is necessary to engage the community in organizing tourist villages through various steps, namely observation of problems; community approach; Pokdarwis Optimization; destination development; development of partnership networks; branding, promotion and marketing of Smart BUMDes; Smart BUMDes app development. There were 31 respondents involved in this study. All respondents were members of Community based tourism "Pokdarwis", BUMDes Tirto Manunggal and Village Goverment. The data were collected from July 2021 to November 2021 using interview, and observation. The results of this research in the beginning of the program is 25,80% of the respondent was involved to development of tourim village. They still have problem of lack of networks. After several empowerment project and development tourism village through Bartander Website integration to Smart BUMDes, there was an increase to 38,70%. The conclusion is Bartander integration to Smart BUMDes will optimum to utilize as long as there is continuing community empowerment. All the respondent were in active involvement to support the project. Respondent have responsibility to continue the project in the future due to they get benefit from the project, especially improve income. Community engagement will be better if the mentoring approach can be more intense in the future. [ABSTRACT FROM AUTHOR]

Various fields have been using Rest API-based web services in multipleareas, one of which is the health sector. One of its uses is to provide data to those who need it. However, the Rest API-based web service has security flaws that make the data it offers vulnerable to theft, especially confidential data such as medical records. Many studies discuss the use of Rest API-based web services for the integration of medical record data. However, most of these studies do not discuss the application of security to integrated medical record data. This study answers this gap by implementing Rest API security using the access token security method on the web service to secure integrated medical record data. We need to do this because medical record data contains confidential data belonging to many patients. To prevent unauthorized parties from accessing medical records, we use the access token security method. In addition, we carried out web service security testing to ensure web service security is running correctly. This test is done by SQL injection and brute force attackdirected at the web service and analyzing the results. The results of this study are a web service that secures medical record data by using an access token security method that is safe from SQL injection and brute force attacks. With this web service, we hope to reduce the potential for medical record data leakage significantly. [ABSTRACT FROM AUTHOR]

TiO2 nanoparticles have properties as light absorbers to be used as light catalysts or solar cells. This study aimed to determine the effect of adding TiO2 nanoparticles to the structure and morphology of bacterial cellulose-based membranes produced from pineapple peel waste. The research was conducted by producing pellicles from pineapple peel extract. The pellicle was then disintegrated in 6 cycles using a high-pressure homogenizer at 150 bar. TiO2 variations were 0.5%, 1.0%, 1.5%, 2.0%, and 2.5%wt. They were sonicated and dried in an oven for 8 hours at 60°C. The structure was analyzed using XRD, and SEM observed morphology. The results showed that in the BC membrane with additional TiO2, a new peak occurred on the diffractogram at 2θ=25.05°. It indicated the presence of TiO2 nanoparticles in the membrane. The diffraction peak occurred at 22.49° indicating that the cellulose belonged to Iβ cellulose. Additional 0% to 1% of TiO2 increased the membrane crystallinity index from 81.35% to 81.52%. The membrane crystallinity index decreased after an additional 1% TiO2, valuing 81.52% to 80.16% in the 2.5% sample. The membrane surface morphology showed that the TiO2 nanoparticles were still agglomerated and not evenly distributed on the BC membrane. [ABSTRACT FROM AUTHOR]

Cellulose produced from bacteria is a biopolymer that having high strength, purity and permeability so that it can be applied in various fields. The study aims to observe the morphology and structure of BC after being treated by a chemical reagent. The study was conducted using a BC pellicle that was produced from an extract of pineapple peel waste after being fermented for 10 days by Acetobacter xylinum. BC pellicle was treated by a chemical reagent solution (BmimCl, H2O2, and NaOH) by a concentration of 5%. BC pellicle was immersed in chemical reagent at 80 °C for 2 hours then dried in an oven for 6 hours at 70°C. The morphology observation was conducted under the Scanning Electron Microscope, and the structure was analysed using XRD apparatus. The results indicate that diffractogram of BC film after chemical pretreatment, the crystal size of BC film reduce from 10.01 nm (without treatment) to 3.67 nm, 3.62 nm, and 3.68 nm for pretreatment fo NaOH, H2O2, and BmimCl, respectively. The highest crystallinity of BC film was obtained by pretreatment using H2O2 with a crystallinity of 76.83%. The morphology of BC film indicated that pretreatment using NaOH, H2O2, and BmimCl cause peel of BC nanofiber so that the surface of BC film looks rougher and more porous. [ABSTRACT FROM AUTHOR]

This study explores the correlation of PEG addition to the morphology and functional groups of the bacterial nanocellulose (BNC) – TiO2 composite membrane. The methods include the production of BC pellicle from the fermentation of pineapple peel waste extract using Acetobacter xylinum. Impurities from the BC pellicle was removed by immersing it in 1% NaOH solution. BNC was synthesized by using a blender, high-pressure homogenizer and vacuum filter. The composite membranes consisted of 10 grams BNC, 1% TiO2 and PEG with different mass percentages of 0.5%, 1% and 2%. They were mixed using a magnetic stirrer and were dried at 80oC-14 hours using an oven. Dry composite membrane analyzed based on its functional groups using FTIR, respectively. The results show that FTIR analysis identified peaks of 2904 cm-1, 1174 cm-1, 2131 cm-1and 3414 cm-1, and they corresponded to C-H, C-O-C, C≡C, and O-H bond, respectively. [ABSTRACT FROM AUTHOR]

Additive manufacturing has a role in term manufacturing process for creating a part. Additive manufacturing has also popular name that is called 3D printing technology. The 3D printed part is identified as composite material because its strength depends on the orientation layer and the density of material. The surface quality, printing time, and strength of 3D printed part is still observed and developed. So, the purpose of research is to observe the surface quality and strength of 3D printed part to different layer height and orientation of deposit layer in Polylactic Acid material (PLA). The experimental test involved a 3D printer machine to print the specimen regarding to ASTM D3039. Furthermore, the surface roughness of specimen was measured by using SurftestSJ-301 Mitutoyo device. While the tensile was conducted by universal tensile test machine. The layer height of the test specimen was varied from 0.15 mm to 0.25 mm with the increment of 0.5 mm for each specimen. The layer orientation of deposit material was also varied to 0°, 45° to 90°. Base on the observation and analysis, the highest roughness was on the Lh:0.25 mm (12.7 μm) with layer orientation of 45°, whereas the lowest roughness was on the Lh:0.25 mm (0.51 μm) with layer orientation of 90°. The maximum to minimum of material tensile strength were 395.64 kgf, 174.230 kgf and 72.750 kgf for orientation of deposit layer of 90°, 45°, 0° respectively. [ABSTRACT FROM AUTHOR]

As a unique structure, aluminum (Al) foam is extensively used in heat transfer, low weight-high stiffness structure, and energy absorption applications to answer the new technological needs in energy saving. This study analyzed the compressive strength of open-cell Al foam fabricated using spherical silica gel (SiO2) particles as a space holder with the variation of particle grain size. The Al scraps were initially melted inside the furnace at 800 °C and subsequently poured into a heated cylindrical steel mold filled with SiO2 having various particle sizes. The vacuum pressure was spontaneously applied just after the melt completely fill the pouring basin. After the remained SiO2 had been removed from the foam specimens, the porosity was measured. The compressive test was conducted on the cylindrical foam specimens using the universal testing machine (UTM) and the macroscopic appearance of outer cellular fracture was captured during the test. The results showed that the larger SiO2 size generates the higher porosity level of 63% at 5 mm particle size. This higher porosity corresponds to the forming of the larger size of pores in the center of specimens. Consequently, at higher porosity, the compressive strength value obtained was lower with only 4.10 MPa, compared to those with the particle size of 3 mm (10.41 MPa) and 4 mm (6.25 MPa), as confirmed by the compression test. The data obtained from the experiment could provide an overview for those who want to develop Al foam with a certain level of strength. [ABSTRACT FROM AUTHOR]

Magnetic property studies were carried out in the Upper Bengawan Solo River, a section of Solo-Ngawi. Magnetic susceptibility values (χ) were measured at 135 points with an interval of ±500 m on both sides of the river. Low susceptibility (0 to 19.5 × 10−3 SI units) located on agricultural land, and high susceptibility (33.9 to 91.8 × 10−3 SI units) along rivers. River sediment samples were extracted using a mechanical magnetic extraction method. The chemical compounds identified from XRF and FTIR characterization were iron oxide compounds with the highest concentration. The XRD characterization results show the mineral structure of magnetite (Fe3O4) and anorthite (Ca(Al2Si2O8). The hysteresis curve shows a single domain (SD) reversal magnetization. The magnetic properties of river sediments identified are derived from magnetite minerals. [ABSTRACT FROM AUTHOR]

This research investigates bacterial nanocellulose (BNC) composite reinforced with Titanium Dioxide (TiO2) in terms of morphology and membrane functional groups. Cetyltrimethylammonium Bromide (CTAB) was used as a surfactant. The purpose of this research is to investigate the effect of addition CTAB on the membrane composite. Bacterial cellulose (BC) pellicle was produced from the extract of pineapple peel waste. Acetobacter xylinum was used as the fermentation agent. The solution of 1% NaOH was applied for removing the BC pellicle impurities. Mechanical treatment and high pressure homogenize process had been done to synthesize BNC. The composite membranes were synthesized by using a mixture of BNC, TiO2 1%, and CTAB with different mass percentages, 0.5%, 1%, and 2%, and then the composite solution was dried by the oven for 14 hours at 80 °C. Properties of the composite membrane can be known based on its morphology and functional groups. Scanning Electron Microscope was used to observe the morphology. The results show that a higher concentration of CTAB makes BNC structure became more porous, and TiO2 particles spread more uniformly. FTIR analysis was conducted in range of 682cm-1, 862cm −1, 1041cm −1 and 3421 cm−1. Successively, they are the position of the C-OH, C-H, C-O-C, and O-H function clusters. [ABSTRACT FROM AUTHOR]

Several methods of processing microtremor data have been developed, including Spatial Autocorrelation or Spatially Averaged Coherency Spectra (SPAC) Method. Various types of array shapes in this method such as linear-shaped, L-shaped, triangle-shaped, and circular-shaped array. Among them, the triangle array is the most common. Due to some limitations on the field during the survey, sometimes the triangle array is more difficult to deploy where only L shape array can be done. The purpose of this study is aimed to evaluate the L-shaped array in estimating shear wave velocity structure. Data acquisition was conducted next to the micro-seismic monitoring station of the Experimental Power Reactor (RDE) Site, South Tangerang, Indonesia. An L-shaped array with a combination of different array sizes and the azimuth angle is performed. The phase velocity dispersion curves and shear wave velocity curves of L-shaped arrays with the same array size and different azimuth coincide quite well with those of L-shaped arrays with the same different azimuth and array size. It observed that the different combinations in terms of array size and azimuth produce similar shear wave velocity profiles. Based on the results of the analysis, an L-shaped array can be utilized in order to estimate the shear wave velocity structure. [ABSTRACT FROM AUTHOR]

Allee effect and harvesting are two important objects in the ecological system since they are directly connected to the existence of biological resources. Here, we study the impact of the strong Allee effect in prey and Michaelis-Menten type of harvesting in predators on the dynamics of a Gause-type predator-prey model. To involve the influence of the memory effect, the Caputo fractional-order derivative is applied. As a preliminary analysis, we obtain three types of equilibrium points namely the origin point, a pair of the predator extinction points, and the co-existence point. Some interesting dynamics are shown such as the local stability for each equilibrium point, the existence of transcritical bifurcation around the predator extinction points, and the occurrence of Hopf bifurcation around the co-existence point. Furthermore, some numerical simulations are performed to reinforce the theoretical findings. [ABSTRACT FROM AUTHOR]

We consider a Leslie-Gower model with the Beddington-DeAngelis functional response, Allee effect, and Caputo fractional order derivative. We first establish the existence, uniqueness, non-negativity, and boundedness of solutions to confirm the biological feasibility of the model. Moreover, the Lyapunov direct method including the generalized LaSalle invariance principle is applied to investigate the global stability of the prey-free point and the co-existence point. By using the Adams-Bashfort-Moulton for the fractional order system, we perform some numerical simulations to justify the theoretical results. [ABSTRACT FROM AUTHOR]

In this paper, we study optimal control and cost-effectiveness of several schistosomiasis control strategies. The control strategies investigated are health education, molluscicide use, and the combination of health education and molluscicide intervention. To solve the optimal control problem, we use Pontryagin's maximum principle. We compute the average cost- effectiveness ratio (ACER) and incremental cost-effectiveness ratio (ICER) to identify the most cost-effective strategy. The results show that the most cost-effective strategy to control schistosomiasis in the region with adequate sanitation is health education intervention. On the other hand, molluscicide intervention is the most cost-effective strategy to control schistosomiasis in the region with inadequate sanitation. Furthermore, the most effective strategy to eliminate schistosomiasis is the combination of health education and molluscicide intervention. [ABSTRACT FROM AUTHOR]

Bacterial cellulose has many advantages when applied in various fields, such as medic. This research reported the fibrillation process effect on bacterial cellulose using a blender and HPH on bacterial cellulose produced from pineapple skin waste. The produced pellicle after the fermentation process was cleaned and received treatment from a blender and a High-Pressure Homogenization (HPH) machine. After that, the bacterial cellulose was dried using a freeze-drying method. Use scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) to observe bacterial cellulose. The SEM results showed that the HPH treatment created a more homogenous porosity in the bacterial cellulose. The XRD result presented that similar crystal positions were found at 14°, 16°, and 22°. The HPH treatment produced a higher crystallinity value. The FTIR test showed that the fibrillation process did not change the bonds of bacterial cellulose. [ABSTRACT FROM AUTHOR]