ANALISIS KENAIKAN HARGA BBM TERHADAP HARGA SAHAM DI BURSA EFEK INDONESIA (STUDY KASUS SAHAM SEKTOR PERTAMBANGAN)

Pada tanggal 22 Juni pemerintah menetapkan harga BBM baru yaitu naik Rp.2000 untuk premium dari Rp.4500 menjadi 6500 dan solar naik Rp.1.000 dari 4500 menjadi Rp.5500. Informasi ini merupakan bagian pengumuman yang mempengaruhi harga dari sekuritas, yaitu pengumumn yang berkaitan dengan adanya kebijakan pemerintah (Goverenment Related Announcement) yaitu adanya peraturan pemerintah baru tentang kenaikan harga BBM. Penelitian ini bertujuan mengetahui perbedaan harga saham perusahaan sektor pertambangan sebelum kenaikan harga BBM dan sesudah kenaikan harga BBM. Pengujian ini dilakukan dengan cara analisis statistik., analisis statistik menggunakan metode uji beda yaitu paired sample t-test, untuk menguji apakah ada perbedaan harga saham pertambangan sebelum kenaikan harga BBM dengan dengan sesudah kenaikan harga BBM. Hasil penelitian ini menunjukkan bahwa nilai rata-rata harga saham pada perusahaan sektor pertambangan pada hari-hari sebelum kenaikan harga bahan bakar minyak lebih tinggi dibandingkan pada saat setelah kenaikan harga bahan bakar minyak, yaitu Rp.1221.0267 pada saat sebelum dan Rp.1179.3778 pada saat setelah kenaikan BBM. Berdasarkan uji t dengan level 5% terdapat perbedaan yang signifikan antara lima hari sebelum kenaikan bahan bakar minyak (BBM) dengan lima hari setelah kenaikan harga bahan bakar minyak (BBM). Hal ini dibuktikan dengan hasil uji beda yaitu nilai probabilitas (Sig-t) sebesar 0,027 yang nilainya di bawah level signifikan 0,05. Hal ini berarti terdapat perbedaan yang signifikan ratarata harga saham pada 5 hari sebelum kenaikan harga BBM dengan 5 hari setelah penetapan kenaikan harga BBM. Kata kunci : kenaikan Harga BBM, Harga Saham Perusahaan sektor Pertambangan dan , Event Studies

FABRICATION OF Mg-Zn-Al HYDROTALCITE AND ITS APPLICATION FOR Pb2+ REMOVAL

The fabrication of Mg-Zn-Al Hydrotalcite (HT) was carried out by the co-precipitation method at various molar ratios. The Mg-Zn-Al HT compound at the optimum molar ratio was then calcined to determine the effect of calcination on the Pb2+ adsorption. The kinetics of the adsorption type was determined by applying pseudo first order and pseudo second order kinetics models. Meanwhile, to investigate the adsorption process, the Freundlich and Langmuir equations were applied to determine the adsorption isotherm. The results showed that the optimum Mg-Zn-Al HT was at a molar ratio of 3 : 1 : 1 with an adsorption efficiency of 73.16 %, while Mg-Zn-Al HT oxide increased the adsorption efficiency to 98.12 %. The optimum condition of Pb2+ removal using Mg-Zn-Al HT oxide was reached at pH 5 and a contact time of 30 minutes. The adsorption kinetics follows the pseudo second order kinetics model with a rate constant of 0.544 g/mg·min. The isotherm adsorption follows the Langmuir isotherm model with a maximum capacity of 3.916 mg/g and adsorption energy of 28.756 kJ/mol

SYNTHESIS OF Mg/Al HYDROTALCITE-LIKE FROM BRINE WATER AND ITS APPLICATION FOR METHYL ORANGE REMOVAL: A PRELIMINARY STUDY

The objective of this research is to synthesis of Mg/Al hydrotalcite-like (Mg/Al HTlc) from brine water and its application as a methyl orange (MO) removal. The research initiated with the synthesis of Mg/Al HTlc from brine water, which is well known as the desalination process wastewater. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The determination of optimum acidity, adsorption rate, and energy and capacity adsorption were studied. The result showed that pH 4 was the optimum acidity for the adsorption of MO on Mg/Al HTlc. MO was adsorbed at pseudo-second order adsorption rate of 1.03 × 105 g mol-1 min-1 on the Mg/Al HTlc. The adsorption data fitted well into the linearly transformed Freundlich equation. Keywords: adsorption, brine water, methyl orange, Mg/Al hydrotalcite-lik

Perencanaan Struktur Gedung Dental Nano Malang Dengan Metode Beton Pracetak (precast)

Metode beton pracetak (precast) adalah teknologi konstruksi struktur beton dengan komponen-komponen yang dicetak terlebih dahulu pada suatu tempat khusus (fabrication) dan selanjutnya dipasang di lokasi proyek (installation). Pemakaian metode beton pracetak (precast) memiliki beberapa kelebihan meliputi waktu pengerjaan yang relatif singkat, proses produksinya tidak tergantung cuaca, tidak memerlukan tempat penyimpanan material yang luas, kontrol kualitas beton lebih terjamin, hemat akan bekisting dan penopang bekisting, serta kemudahan dalam pelaksanaannya Proyek Desain Rumah Sakit Dental Nano merupakan salah satu gedung bertingkat 10 lantai yang terletak di Jalan Ir. Soekarno Hatta No. 6-8 Malang dengan menggunakan metode pembangunan cast in situ. Pada proyek tugas akhir terapan ini akan dibuat dengan menggunakan metode pracetak khusus pada elemen struktur balok dan pelat. Gedung ini dirancang menggunakan Sistem Rangka Momen Khusus (SRPMK). Hasil perencanaan Gedung Dental Nano ini meliputi ukuran pelat dengan tebal 13 cm, dimensi balok induk 40/60, dimensi balok anak 30/40, dan dimensi kolom 75x75 cm. Sambungan antar elemen pracetak menggunakan sambungan basah dan konsol pendek. ================================================================= Precast method is concrete construction technology using components which casted first at fabrication and then casted in project location (installation). This method has several advantages than conventional method. Such as a relatively short working time, the production process not depending at weather, unnecessary too much space of material storage, quality control of the concrete is more aassured, more efficient of formwork, and ease of implementation. Dental Nano Hospital Design Project is one of the 10 storey building located on St. Ir. Soekarno Hatta No. 6-8 Malang using the method of cast in situ development. In the applied final project will be made by using a precast method on the structural elements of the beams and plates. The building was designed using a Special Moment Frame System (SRPMK). The results of this Dental Nano Building include plate size with 13 cm thick, 40/60 premier beam dimension, 30/40 sekunder beam dimension, and 75x75 cm column dimension. Connection between precast elements using wet connection and short consol

Peran Modal Sosial Dalam Mempertahankan Eksistensi Komunitas Friendship Futsal Di Salatiga Pada Masa Pandemi Covid-19

Penelitian ini bertujuan mengetahui peran modal sosial dalam mempertahankan eksistensi komunitas friendship futsal di Salatiga pada masa pandemi covid-19. Untuk mengetahui modal sosial yang berpengaruh terhadap eksistensi komunitas friendship futsal diperlukan informasi mengenai struktur, sistem, nilai, jaringan komunitas, peraturan dan kebijakan yang telah dimiliki dan diterapkan oleh komunitas. Jenis penelitian yang digunakan dalam penelitian ini adalah deskriptif, dengan menggunakan metode penelitian kualitatif. Teknik pengumpulan data dilakukan dengan observasi, wawancara, dan dokumentasi. Partisipan ialah anggota Friendship Futsal. Teori yang digunakan di dalam penelitian ini merupakan teori modal sosial milik Fukuyama. Dalam penelitian ini ditemukan bahwa modal sosial yang dimiliki oleh anggota Friendship Futsal, bersifat mengikat juga menghubungkan, karena modal sosial yang dimiliki oleh anggota Friendship Futsal dalam bentuk norma/nilai yang mempersatukan mereka, rasa saling percaya, dan jejaring yang mereka bentuk ini diterapkan di antara mereka sebagai sesama anggota Friendship Futsal

Mg/Al HYDROTALCITE-LIKE SYNTHESIZED FROM BRINE WATER FOR EOSIN YELLOW REMOVAL

Attempts to synthesis of Mg/Al HTlc using magnesium from several raw material resources are widely investigated. One of raw material would purpose as source of magnesium to synthesis of Mg/Al HTlc is brine water which is well known as the desalination process wastewater. Mg/Al HTlc are widely investigated for their potential applications in research and industrial processes as adsorbents, anionic exchange, catalysts and /or catalyst precursors for the preparation of inorganic materials and pharmaceutical industry excipients. As adsorbents, Mg/Al HTlc are receiving greater interests in the environmental community due to their high adsorption capacity. However, there is no literature available on the synthesis of Mg/Al HTlc from brine water except from artificial seawater. The objective of this research is to synthesis of Mg/Al HTlc from brine water and its ability tested for eosin yellow (EY) removal. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The effect of various experimental parameters was investigated using a batch adsorption technique. In this manner, the adsorption isotherms, adsorption kinetics, and pH effects upon EY adsorption on Mg/Al HTlc were examined. The result showed that EY data fit well with the pseudo-second order kinetic model. The isothermal data could be well described by the Freundlich equation. The adsorption capacity was 2.41 × 10-1 mol g-1, and adsorption energy of EY was 24.89 kJ mol-1. Keywords: Mg/Al hydrotalcite-like, brine water, adsorption, eosin yellow, adsorption capacit

STUDI PENDAHULUAN PEMANFAATAN LIMBAH DESALINASI UNTUK PEMBUATAN Mg/Al HYDROTALCITE-LIKE SEBAGAI ADSORBEN METHYL ORANGE

The utilization of industrial wastewater into a versatile material that has been the focus of research for economics reasons, environmental and technical. One of the proposed industrial wastewater for a new useful material is wastewater from the desalination process which is also known as brine water. The magnesium content in brine water is able to used as a source of magnesium for the synthesis of Mg/Al hydrotalcite-like compound (Mg/Al HTlc). Mg/Al HTlc are widely investigated for their potential applications in research and industrial processes as adsorbents, catalysts and /or catalyst precursors and pharmaceutical industry excipients. As adsorbents, Mg/Al HTlc are receiving greater interests in the environmental community due to their high adsorption capacity. However, before using natural brine water, has conducted a preliminary study the synthesis of Mg/Al HTlc by using artificial brine water as a model of desalination wastewater. The objective of this research is to synthesis of Mg/Al HTlc from artificial brine water and its ability tested as a methyl orange (MO) adsorbents. The research initiated with the synthesis of Mg/Al HTlc from artificial brine water. Characterization of the Mg/Al HTlc synthesized was confirmed through X-ray Diffraction and FT-IR Spectroscopy. The determination of optimum acidity, adsorption rate, and energy and capacity adsorption were studied. The result showed that pH 3 was the optimum acidity for the adsorption of MO on Mg/Al HTlc. MO was adsorbed at first order adsorption rate of 7.30 × 10-4 s-1 on the Mg/ Al HTlc, the adsorption capacity and adsorption energy were 4.36 × 10-5 mol g-1 and 27.54 kJ mol-1, respectively. From the preparatory process and the synthesis of Mg/Al HTlc by using artificial brine water to provide the information that the byproduct of desalination processes (brine water) which are believed to be used for the synthesis of Mg / Al HTlc. Keywords: wastewater, desalination, Mg/Al hydrotalcite-like, artificial brine water, adsorption, methyl orang

The Effect Of Sulphur (S) Doping and K+ Adsorption To The Electronic Properties Of Graphene: A Study By DFTB Method

A study on the effect of S doping and K+ adsorption to the electronic properties of graphene has been conducted by DFTB (Density Functional Tight Binding) calculation. The supercell of 40 x 40 x 1 configured from the 4x4x1 unit cell of graphene was optimized. The calculation shows that the Fermi level of graphene shifted from -4.67 eV into -3.57 eV after S doping. In addition, the S presence caused the formation of gap within the Dirac K of valence band and conduction band. Meanwhile, K+ charge distribution was dominantly occurred within the S-graphene than the graphene

CHARACTERIZATION AND ACTIVATION OF NATURAL ZEOLIT FROM PONOROGO

Characterization and activation of Natural Zeolite from Ponorogo (ZAP) have been done to improve the quality of zeolite as porous material. Analysis of mineral composition is done using X-Ray Difraction (XRD), Fourier Transform-Infra Red (FTIR) Spectroscopy and metal analysis using Atomic Absorption Spectroscopy (AAS). Characterization of the activated zeolite covered about number of acidic sites, surface area, ratio Si/Al and metal composition (Na, Ca, K and Fe). Activated processes is done using various mineral acid, i.e HCl, HNO3, H2SO4 and HPO4 with each concentration at 1 M and 3 3 hours dipping. The result showed that ZAP has composition Ca-klinoptilolit (43.09 %), gismondin (17.57 %), modernit (4.21 %) and quartz (10.37 %). The most efectif of the acid to activate is HCl and is proved to absorp of Zn in waste water. The effect of chemical activation is increasing the ratio of Si/Al, increasing the surface area and reducing some metal composition.   Keywords: natural zeolite, chemical activation, porous materia

Pelatihan Keselamatan Bahan Gas Berbahaya Untuk Teknisi Mesin Pendingin

Pelatihan keselamatan bahan gas berbahaya untuk teknisi mesin pending telah dilaksanakan untuk teknisi mesin pendingin yang tergabung dalam paguyuban Aneka Jasa Teknik Surakarta (AJTS). Kecelakaan kerja berkaitan dengan gas freon banyak diberitakan di dunia maya. Paguyuban AJTS merupakan perkumpulan dari teknisi yang banyak berkecimpung sebagai teknisi mesin pendingin terutama AC, kulkas, dan freezer di Solo Raya. Pelatihan ini penting untuk dilakukan untuk membekali teknisi tersebut agar selamat dalam perakitan dan perbaikan mesin pendingin. Pelatihan ini dilaksanakan secara luring meliputi ceramah keselamatan bahan, praktek mengenal MSDS, dan praktek mendeteksi kebocoran gas freon menggunakan alat leaking detektor. Hasil pelatihan antara lain: peserta paham tentang bahaya gas freon dan pencegahan kecelakaan kerja dalam penanganan mesin pendingin. Pelatihan sangat bermanfaat bagi teknisi mesin pendingin terutama peserta pelatihan dan pembaca artikel ini, sehingga keselamatan kerja dapat tercapai