Pembuatan dan Karakterisasi Keramik Magnesium Alumina Silika dari Abu Vulkanik Gunung Sinabung

Berlimpahnya material abu vulkanik Gunung Sinabung merupakan suatu hal yang menarik untuk diteliti lebih lanjut, khusunya tentang kelayakan penggunaan abu vulkanik tersebut sebagai bahan dasar untuk membuat material keramik magnesium alumina silika. Sebagian besar abu vulkanik tersebut belum termanfaatkan sama sekali. Material keramik dibuat dari bahan dasar yang tersusun atas abu vulkanik, alumina silika (Al2O3) dan Magnesium Oksida (MgO). Keberadaan abu vulkanik hasil dari letusan Gunung Sinabung merupakan hal yang cukup potensial sebagai pembuatan bahan keramik.Tujuan dari penelitian ini adalah membuat keramik yang keras dan kuat dari abu vulkanik Gunung Sinabung dan untuk mengetahui pengaruh penambahan Al2O3 dan MgO pada pada sampel material keramik. Sekaligus untuk mengetahui proses pembakaran (sintering) yang optimal terhadap karakterisasi dari sampel keramik yang meliputi sifat fisik, kekerasan dan struktur Kristal dari material.Adapun hasil dari penelitian yang telah dilakukan untuk memnuhi tujuan tersebut adalah nilai densitas tertinggi dengan komposisi abu (80%), Al2O3 (10%) dan MgO (10%) adalah 2.06 gr/cm2 dengan suhu pembakaran 1200 0C, morfologi yang baik pada komposisi yang sama dengan suhu pembakaran 1200 0C, fasa yang dominan terbentuk adalah Silika oksida (SiO2), dan fasa lainnya MgSiO3, Al₂MgO₄ dan hasil kekerasan yang diperoleh sebesar 768.21 kgf/mm2

Pemanfaatan Surat Keterangan Asal Indonesia dalam Peningkatan Investasi Berorientasi Ekspor Australia ke Indonesia

Indonesia has signed a trade agreement with Australia and hoped that this agreement can benefit both parties in facing global free trade. Indonesia is not Australia's main trading partner currently and Indonesia's exports to Australia tend to decline in recent years. Indonesia can take advantage of Australia's export market which is experiencing an increase in the value of exports which has risen Faster than import prices which has affected the growth of the Australian economy. Indonesia can utilize the export market, especially markets that have trade agreements with Indonesia in order to indirectly increase Indonesian exports by utilizing the issuance of Certificates of Origin from Indonesia as partners of producers of Australian export products. The abundance of natural resources and labor in Indonesia is expected to attract the interest of Australia to invest in Indonesia to build an industry that aims to produce goods for the needs of the country's export market demand and for Indonesia to increase the entry of foreign direct investment to Indonesia

Note on the Occurrence of Phytoplankton and Its Relation with Mass Mortality in the Jakarta Bay, May and November 2004

There were noted two times (May and November 2004), fish mass mortality occurred in the coast of the Jakarta Bay, killing several species of small and big fishes, crustaceans, eels and molluscs. Phytoplankton blooms in the Jakarta Bay is accelerated by the high input of nutrients, which caused eutropication of the Bay water. Analysis of water sample showed in st 1 (Marina coast) showed that phytoplankton abundance was of 2.9 x 106 cells/l-1 , the common diatom species recorded at that time were: Skeletonema costatum, Thalassiosira mala, Bacteriastrum varians, Chaetoceros pseudocurvisetus, Nitzschia sigma, Coscinodiscus radiatus. Of the which: Skeletonema costatum 1.8 x106 cells/l-1 ; in st. 3 Binaria lake was the most a common diatoms species found in the Jakarta Bay. This species frequently bloom, especially after rainfall, causing no harm to marine life, the second diatoms Thalassiosira mala 2.8 x 106 cells/l-1 (st 4 Carnaval coast), during this decade in more often frequencies. The second largest group was represented by four dinoflagellates species: Prorocentrum micans, Protoperidinium sp., Ceratium furca and Gonyaulax sp., and one species dominated of dinoflagellate Prorocentrum micans 2.3 x 106 cells/l-1 (in the Dadap coast). P. micans is also common species of the Jakarta Bay. Hydrological conditions in May and November 2004 are, temperature 32-33 oC, pH 7.76 to 7. 92, Salinity 32‰, Dissolved oxygen 3.88 to 4.26 mg/l, Phosphate 0.10-0.40 ?g-at-P l-1 , Nitrate 0.01 to 0.03 ?g-at-N l-1 . The result suggests that phytoplankton distributes in wider areas than expected and monitoring of its occurrence in Indonesian waters is necessary to prevent harmful effects of such bloom

NOTE ON THE OCCURRENCE OF PHYTOPLANKTON AND ITS RELATION WITH MASS MORTALITY IN THE JAKARTA BAY, MAY AND NOVEMBER 2004

There were noted two times (May and November 2004), fish mass mortality occurred in the coast of the Jakarta Bay, killing several species of small and big fishes, crustaceans, eels and molluscs. Phytoplankton blooms in the Jakarta Bay is accelerated by the high input of nutrients, which caused eutropication of the Bay water. Analysis of water sample showed in st 1 (Marina coast) showed that phytoplankton abundance was of 2.9 x 106 cells/l-1 , the common diatom species recorded at that time were: Skeletonema costatum, Thalassiosira mala, Bacteriastrum varians, Chaetoceros pseudocurvisetus, Nitzschia sigma, Coscinodiscus radiatus. Of the which: Skeletonema costatum 1.8 x106 cells/l-1 ; in st. 3 Binaria lake was the most a common diatoms species found in the Jakarta Bay. This species frequently bloom, especially after rainfall, causing no harm to marine life, the second diatoms Thalassiosira mala 2.8 x 106 cells/l-1 (st 4 Carnaval coast), during this decade in more often frequencies. The second largest group was represented by four dinoflagellates species: Prorocentrum micans, Protoperidinium sp., Ceratium furca and Gonyaulax sp., and one species dominated of dinoflagellate Prorocentrum micans 2.3 x 106 cells/l-1 (in the Dadap coast). P. micans is also common species of the Jakarta Bay. Hydrological conditions in May and November 2004 are, temperature 32 – 33 oC, pH 7.76 to 7. 92, Salinity 32 ‰, Dissolved oxygen 3.88 to 4.26 mg/l, Phosphate 0.10 – 0.40 µg-at-P l-1 , Nitrate 0.01 to 0.03 µg-at-N l-1 . The result suggests that phytoplankton distributes in wider areas than expected and monitoring of its occurrence in Indonesian waters is necessary to prevent harmful effects of such bloom. Keywords: The occurrence of phytoplankton, mass mortality, The Jakarta Ba

ANALISA PENGARUH BEBAN SUHU TERHADAP KUAT TEKAN BETON PADA PELAT BETON BERTULANG

ANALISA PENGARUH BEBAN SUHU TERHADAP KUAT TEKAN BETON PADA PELAT BETON BERTULANG

Analisis Komparatif Kebijakan Perpajakan Atas Kegiatan Filantropi

This study aims to analyze tax exemption and tax deduction policies on philanthropic activities in Indonesia and some other countries as a basis of recommendation in improving taxation policies to encourage philanthropic activities in Indonesia. Comparative analysis was conducted towards the similar policies in 4 selected namely, the United States, Myanmar, Sri Lanka, and Malaysia. The data used in this study were obtained from the CAF World Giving Index 10th report, A Global Philanthropy Legal Environment Index, the World Bank List of economies 2019, and tax regulations from the selected countries. Data analysis was conducted through comparative analysis methods supported by primary data, namely the results of interviews and secondary data, namely the results of literature reviews. The results of the analysis show that the tax exemption and tax deduction policies for philanthropic activities in Indonesia are adequate. There are several tax exemption and tax deduction policies on philanthropic activities from the selected countries that can be used as a basis of recommendation and consideration in the formulation and improvement of the related tax policies in Indonesia

A Multimodal Analysis on A Vocational English Book and Its Effect on Students' English Proficiency

The digitization of education is the use of technology as an aspect of the learning system, from the curriculum to the education system, which has a very big influence on innovation. As society and academic demand increase in the modern era, the online learning system (OLS) is encountered by society and academics. The multimodal approach refers to the huge learning competence in English ability as if the method or application is integrated in a digitizing manner. The multimodal approach contains using images, verbal and visual integration with words or text which provides meanings in the mode of communication. The process of analyzing and disclosing the text will give essence to the meaning of a picture message in a printed book will reveal projection, enhancement, concurrence. All of which are discussed based on linguistic analysis to relate the text to the general characteristics of language both verbally and visually. Systemic function Linguistics based on the concept of metafunction has ideational, interpersonal, and textual components linking the internal forms of language and their use in semiotic social contexts will be enacted to the research. The research will use descriptive and qualitative methods

The condition of megabenthos and reef fish in coral reef ecosystems in Aru Islands National Conservation Area, Southeast Maluku, Indonesia

The waters of the Aru Islands are part of the National Marine Protected Areas (MNR), and have extensive coral reefs with high biodiversity. The study was conducted in October 2016 at twelve stations to determine the status of coral cover, composition, and density of megabenthos and reef fishes. Coral reef data collection refers to the Underwater Photo Transect (UPT), and data processing uses Coral Point Count for Excel (CPCe). The Benthos Belt Transect (BBT) method was used for megabenthos data, and the Underwater Visual Census (UVC) method was used for reef fish observations.The result of the benthic component analysis showed that the proportion of live corals at each station ranged from 10.60% to 54.27%, with an average cover value of 31.21%, which fell into the “fairly good” category. Megabenthos density analysis revealed that Drupella cornus had the highest density value (0.29 individuals/m2) and Holohuria edulis (0.01 individuals/m2) had the lowest density. Analysis of the reef fish community revealed that the indicator fish were 168 individuals from the family Chaetodontidae. The group of herbivore fish recorded 116 individuals from threee families: Acanthuridae, Scaridae, and Siganidae. Acanthurus auranticavus and Acanthurus pyroferus are common species found in the waters of the Aru Islands

Resting cyst distribution and molecular identification of the harmful dinoflagellate Margalefidinium polykrikoides (Gymnodiniales, Dinophyceae) in Lampung Bay, Sumatra, Indonesia

Margalefidinium polykrikoides, an unarmored dinoflagellate, was suspected to be the causative agent of the harmful algal blooms - associated with massive fish mortalities - that have occurred continually in Lampung Bay, Indonesia, since the first bloom event in October 2012. In this study, after examination of the morphology of putative M. polykrikoides-like cysts sampled in bottom sediments, cyst bed distribution of this harmful species was explored in the inner bay. Sediment samples showed that resting cysts, including several morphotypes previously reported as M. polykrikoides, were most abundant on the northern coast of Lampung Bay, ranging from 20.6 to 645.6 cysts g(-1) dry sediment. Molecular phylogeny inferred from LSU rDNA revealed that the so-called Mediterranean ribotype was detected in the sediment while M. polykrikoides motile cells, four-cell chain forming in bloom conditions, belonged to the American-Malaysian ribotype. Moreover, hyaline cysts, exclusively in the form of four-cell chains, were also recorded. Overall, these results unequivocally show that the species M. polykrikoides is abundantly present, in the form of vegetative cells, hyaline and resting cysts in an Indonesian area