Profil Perkembangan Bakat Khusus Peserta Didik di Kelas VIII SMP Negeri 1 Siberut Selatan Kabupaten Kepulauan Mentawai

Penelitian ini dilatarbelakangi adanya peserta didik kurang mampu memahami dan mengingat pelajran yag diberikan guru, kurang mampu berbahasa indonesia, kurang mampu menghitung pelajaran matematika, nilai raport semester 1 rendah dibawah KKM, malas mengikuti kegiatan di sekolah, nilai seni kebudayaan di bawah KKM, dan kurang dukungan, motivasi dari orang tua peserta didik. bertujuan penelitian ini adalah mendiskripsikan: 1. bakat akademik khusus, 2. bakat seni. 3.bakat kinestetik/psikomotor, 4. bakat sosial. Penelitian ini dilakukan dengan menggunakan metode deskriptif kuantitatif, populasi penelitian adalah 150 peserta didik. teknik pengambilan sampel (Proportional Random Sampling), yaitu sebanyak 60 peserta didik. Data penelitian ini diperoleh melalui angket dan diolah menggunakan teknik persentase. Berdasarkan hasil dari penelitian yang dilakukan di SMP Negeri 1 Siberut Selatan Kabupaten Kepulauan Mentawai dapat diambil kesimpulan sebagai berikut: a) bakat untuk bekerja angka-angka (Numerika) berada pada kategori banyak sebanyak 5 orang (71,66%), b) Bakat dalam menggunakan bahasa berada kategori sangat banyak sebanyak 35 orang (58,33%), c) Bakat mampu mengaransemen dan sangat dikagumi berada kategori cukup banyak sebanyak 14 orang (23,33%), dan d) Bakat memciptakan lagu dalam 30 menit berada pada kategori cukup banyak sebanyak 27 orang (45%). Hasil penelitian ini direkomendasikan kepada guru pembimbing/konselor untuk dapat membantu peserta didik dalam mengembangkan bakat khusus peserta didik  di SMP Negeri 1 Siberut Selatan Kabupaten Kepulauan Mentawai.            &nbsp

Calorific Value Analysis of Azadirachta Excelsa and Endospermum Malaccense as Potential Solid Fuels Feedstock

Thermal conversion of woody biomass to fuel has been intensified in recent decades due to the depletion of fossil fuels, greenhouse effect and high energy demand worldwide. Screening the potential feedstock is being considered as one of the alternatives to identifying the most suitable biomass resources prior to being converted into renewable energy in the form of solid fuels, such as charcoal and briquettes. Generally, high calorific value (CV) indicates high potential of feedstock for briquettes, torrefied wood and coal generation. In this study, CV was characterized using a bomb calorimeter that was based on 3 different ranges of moisture content (MC) that are ? 25%, 20%?25% and ? 20% for two tropical tree species, namely Azadirachta excelsa (Sentang) and Endospermum malaccense (Sesenduk), respectively. This standard method for the characterization process was considered to determine the CV. Average CV for both samples ranged between 16?17 MJ/kg. The highest CV was 17.3490 MJ/kg and 17.1273 MJ/kg for Sesenduk and Sentang, respectively and calorific values were obtained at MC less than 20%. The experimental study demonstrated that the decreasing value of MC has increased the CV because of the high value of oxygen-to-carbon (O/C) ratio in the wood; additionally, the energy density of the wood sample was also improved when CV increased. Both of these species were proved to contain the potential of being feedstock as wood fuel resources, since they carry standard CVs, obtain fast growth with suitable conditions in Malaysia and are grown at very low cost of production for plantations, fertilizer, pesticides, labor, transportation and handling

Synthesis and Structural Study of a Novel La0.67Ca0.33Cr0.9Cu0.1O3-δ Anode for Syngas-Fuelled Solid Oxide Fuel Cell

Solid oxide fuel cell (SOFC) is an alternative energy generation device that converts chemical energy into electrical energy from the use of hydrogen or hydrogen-rich fuel. A light hydrocarbon, e.g. methane (CH4), is a hydrogen-rich fuel that can be used as an alternative fuel to hydrogen in SOFC application. Carbon-containing fuel is accessible from natural gas, biogas, biomass gasification, etc. Biomass gasification produces methane, hydrogen (H2), etc. as syngas products which could be integrated with SOFC. As anode is an outer layer of SOFC which exposes to fuel, the development of anode for carbon-containing fuel application is essential. Conventional Ni-containing anode is found to create carbon deposition which degrades the cell. The replacement of copper (Cu) to Ni has been studied to enhance the direct electrochemical oxidation of dry hydrocarbons which is free from carbon deposition. With the interest of Cu doping, a La-based anode has been doped with 10 % Cu at B-site of perovskite structure as La0.67Ca0.33Cr0.9Cu0.1O3-δ and studied the X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray (EDX) for future application in syngas-fuelled SOFC

Electrochemical Performance of SrWO4 Electrolyte for SOFC

Scheelite structured SrWO4 material was synthesized by the solid-state sintering method and studied with respect to phase stability and ionic conductivity under condition of technological relevance for SOFC applications. The resulting compound was crystallized in the single phase of tetragonal scheelite structure with the space group of I41/a. Room temperature X-ray diffraction and subsequent Rietveld analysis confirms its symmetry, space group and structural parameters. Analysis by SEM illustrated a highly dense structure. SrWO4 sample shows lower conductivity compared to the traditional BCZY perovskite structured materials. SrWO4 sample exhibited an ionic conductivity of 1.93 × 10−6 S cm-¹ at 1000℃ in dry Ar condition. Since this scheelite type compound demonstrated significant conductivity and a dense microstructure, it could serve in SOFC as a mixed ion-conducting electrolyte

A new high-performance proton-conducting electrolyte for next-generation solid oxide fuel cells

N. Radenahmad and A. Afif are thankful to Universiti Brunei Darussalam for sponsoring the UBD graduate scholarship to perform Ph.D. work at Brunei Darussalam. The authors are also grateful to the late Professor Sten Eriksson for supporting a summer scholarship for NR to accomplish a part of this work at Chalmers University of Technology, Sweden. This work was also partially funded by research grant UBD/OVAORI/CRGWG(006)/161201.Conventional solid oxide fuel cells (SOFCs) are operable at high temperatures (700 – 1,000 °C) with the most commonly used electrolyte, yttria‐stabilized zirconia (YSZ). SOFC R&D activities have thus been carried out to reduce the SOFC operating temperature. At intermediate temperatures (400 – 700 °C), barium cerate (BaCeO3) and barium zirconate (BaZrO3) are good candidates for use as proton‐conducting electrolytes due to their promising electrochemical characteristics. Here, we combined two widely studied proton‐conducting materials with two dopants and discovered an attractive composition for the investigation of electrochemical behaviors. Ba0.9Sr0.1Ce0.5Zr0.35Y0.1Sm0.05O3‐δδ(BSCZYSm), a perovskite‐type polycrystalline material, has shown very promising properties to be used as proton‐conducting electrolytes at intermediate temperature range. BSCZYSm shows a high proton conductivity of 4.167×10−3 S cm−1 in a wet argon atmosphere and peak power density of 581.7 mW cm−2 in Ni‐BSCZYSm | BSCZYSm | BSCF cell arrangement at 700 °C, which is one of the highest in comparison to proton‐conducting electrolyte‐based fuel cells reported till now.PostprintPeer reviewe

Enhancement of proton conductivity through Yb and Zn doping in BaCe0.5Zr0.35Y0.15O3-δ electrolyte for IT-SOFCs

The new compositions of BaCe0.5Zr0.3Y0.15-xYbxZn0.05O3-δ perovskite electrolytes (x = 0.1 and 0.15) were prepared by solid state synthesis and final sintering at 1500 °C. The obtained ceramics were investigated using X-ray diffraction, scanning electron microscopy, thermo-gravimetric analysis and impedance spectroscopy. The refinement of XRD data confirmed cubic crystal structure with Pm3m space group for both samples. SEM morphology showed larger and compacted grains which enables obtaining of high density and high protonic conductivity. The relative densities of the samples were about 99% of the theoretical density after sintering at 1500 °C. The protonic conductivities at 650 °C were 2.8×10-4 S/cm and 4.2×10-3 S/cm for x = 0.1 and 0.15, respectively. The obtained results showed that higher Yb-content increases the ionic conductivity and both of these perovskites are promising electrolyte for intermediate temperature solid oxide fuel cells to get high efficiency, long-term stability and relatively low cost energy system

Highly dense and novel proton conducting materials for SOFC electrolyte

S. Hossain and A. M. Abdalla are thankful to graduate studies office of Universiti Brunei Darussalam for graduate research scholarship (GRS) for this research work done. Authors are also grateful to Professor John T. S. Irvine for managing a visiting scholarship for SH and AMA to perform the research work at University of St Andrews, Scotland, UK.Highly dense proton conducting materials of BCZYSZn (BaCe0.8-xZrxY0.15Sm0.05O3-δ (x = 0.15, 0.20) with 4 wt.% ZnO as sintering additive), to be used as an intermediate temperature solid oxide fuel cells (IT-SOFCs) electrolyte, have been processed by the conventional solid state reaction method. The crystalline phase, microstructure, electrical properties, cell performance and chemical stability of the materials have been investigated. The ionic conductivity of BCZYSZn 3 (x = 0.20) material has been measured to be ~2.56 × 10-3 S cm−1 and ~8.32 × 10-3 S cm−1 at 600 °C and 850 °C, respectively in wet 5%H2 in Ar atmosphere. Microstructural characterizations of the zinc containing materials (BCZYSZn) show the formation of highly dense morphology with very large grains. The chemical stability test of BCZYSZn in pure CO2 shows that the material is very stable up to 1000 °C. The maximum power density for the BCZYSZn 3 electrolyte cell is found to be 0.42 W/cm2 at 700 °C under the testing atmosphere. The performed characterizations reveal that these are suitable proton-conducting candidate materials for efficient electrochemical devices.PostprintPeer reviewe

Low-Fouling Plate-and-Frame Ultrafiltration for Juice Clarification: Part 2—Module Design and Application

The purification and concentration of orange juice are crucial to remove undesirable materials, such as pectin, which is responsible for juice clouds; or limonene, which is responsible for bitter taste. Membrane-based juice clarification is preferred due to its capability to separate specific targeted molecules, while still maintaining the clarified juice’s nutritional content. In this study, a novel designed bench-scale plate-and-frame membrane module composed of low fouling cellulose acetate membrane sheets was manufactured to facilitate orange juice clarification. The experimental results demonstrated the effectiveness of the developed module to be used for juice clarification. After incorporating the functional and structural design parameters, the final module had the following specifications: dimensions of 125 × 168 mm, an effective volume of 0.9–9.4 L, a total active membrane area of 1088 cm², and a transmembrane pressure of 0.3–0.55 MPa. The results of the juice clarification show no difference in the value of pH, viscosity, total acid, water content, color L* (brightness), and color a* (reddish) of the feed, the permeate, and the retentate streams. The clarified juice had slightly higher total dissolved solids (◦Brix), ash content, vitamin C, and color (b* yellowish). Overall, our findings demonstrated that the developed plate-and-frame module could effectively be used to clarify orange juice without altering the quality, i.e., reducing the nutritional contents

Improved mechanical strength, proton conductivity and power density in an ‘all-protonic’ ceramic fuel cell at intermediate temperature

The authors AA and NR would like to thank Universiti Brunei Darussalam for providing a UGS scholarship to perform this research. This work was supported by the UBD CRG project: UBD/OVACRI/CRGWG(006)/161201.Protonic ceramic fuel cells (PCFCs) have become the most efficient, clean and cost-effective electrochemical energy conversion devices in recent years. While significant progress has been made in developing proton conducting electrolyte materials, mechanical strength and durability still need to be improved for efficient applications. We report that adding 5 mol% Zn to the Y-doped barium cerate-zirconate perovskite electrolyte material can significantly improve the sintering properties, mechanical strength, durability and performance. Using same proton conducting material in anodes, electrolytes and cathodes to make a strong structural backbone shows clear advantages in mechanical strength over other arrangements with different materials. Rietveld analysis of the X-ray and neutron diffraction data of BaCe0.7Zr0.1Y0.15Zn0.05O3−δ (BCZYZn05) revealed a pure orthorhombic structure belonging to the Pbnm space group. Structural and electrochemical analyses indicate highly dense and high proton conductivity at intermediate temperature (400–700 °C). The anode-supported single cell, NiO-BCZYZn05|BCZYZn05|BSCF-BCZYZn05, demonstrates a peak power density of 872 mW cm−2 at 700 °C which is one of the highest power density in an all-protonic solid oxide fuel cell. This observation represents an important step towards commercially viable SOFC technology.Publisher PDFPeer reviewe

Highly dense and chemically stable proton conducting electrolyte sintered at 1200 °C

The authors S. Hossain and A. M. Abdalla are grateful to the graduate studies office of Universiti Brunei Darussalam for graduate research scholarship (GRS) for funding this research. The authors are thankful to Professor John T. S. Irvine for managing a visiting scholarship for SH and AMA at Center for Advanced Materials at School of Chemistry in University of St Andrews, UK for the research works done.The BaCe0.7Zr0.1Y0.2−xZnxO3−δ (x = 0.05, 0.10, 0.15, 0.20) has been synthesized by the conventional solid state reaction method for application in protonic solid oxide fuel cell. The phase purity and lattice parameters of the materials have been studied by the room temperature X-ray diffraction (XRD). Scanning electron microscopy (SEM) has been done for check the morphology and grain growth of the samples. The chemical and mechanical stabilities have been done using thermogravimetric analysis (TGA) in pure CO2 environment and thermomechanical analysis (TMA) in Argon atmosphere. The XRD of the materials show the orthorhombic crystal symmetry with Pbnm space group. The SEM images of the pellets show that the samples sintered at 1200 °C are highly dense. The XRD after TGA in CO2 and thermal expansion measurements confirm the stability. The particles of the samples are in micrometer ranges and increasing Zn content decreases the size. The conductivity measurements have been done in 5% H2 with Ar in dry and wet atmospheres. All the materials show high proton conductivity in the intermediate temperature range (400–700 °C). The maximum proton conductivity was found to be 1.0 × 10−2 S cm−1 at 700 °C in wet atmosphere for x = 0.10. From our study, 10 wt % of Zn seems to be optimum at the B-site of the perovskite structure. All the properties studied here suggest it can be a promising candidate of electrolyte for IT-SOFCs.PostprintPeer reviewe