PENGARUH PENAMBAHAN BIODIESEL DARI VIRGIN COCONUT OIL PADA BAHAN BAKAR SOLAR TERHADAP UNJUK KERJA MESIN DIESEL EMPAT LANGKAH

Abstrak Minyak solar atau High Diesel Oil (HDO) memiliki peran yang sangat penting untuk memenuhi kebutuhan energi dalam transportasi, industri, dan sektor pembangkit listrik di Indonesia. Namun, yang sebagian besar digunakan untuk sektor transportasi. Permintaan solar meningkat setiap tahun, sedangkan produksi minyak solar di Indonesia terbatas, sehingga impor minyak solar diperlukan untuk memenuhi peningkatan permintaan domestik. Biodiesel merupakan pilihan energi alternatif untuk menggantikan minyak solar terutama untuk sektor transportasi. Kita semua menyadari bahwa Indonesia memiliki potensi besar untuk memproduksi virgin coconut oil sebagai bahan baku alternatif untuk memproduksi biodiesel. Tujuan dari penelitian untuk mengetahui pengaruh campuran solar-biodiesel dari virgin coconut oil terhadap unjuk kerja mesin diesel dan opasitas. Jenis penelitian ini adalah penelitian eksperimen. Pengujian unjuk kerja mesin menggunakan metode fixed full-load fuel injection pump dengan standar pengujian berdasarkan SAE J1349 dan standar pengujian kadar emisi gas buang berdasarkan SAE J1167. Biodiesel ini dicampurkan pada solar dengan presentase  17,5%; 20%; dan 22,5%. Peralatan dan instrumen penelitian yang digunakan adalah smoke opacymeter, ediccurent chasis dynamometer, stopwatch, dan gelas ukur. Analisis data menggunakan metode deskriptif. Dari hasil penelitian menunjukkan bahwa torsi yang dihasilkan mengalami penurunan bahan bakar B17,5 sebesar 1,380%; pada bahan bakar B20 torsi meningkat sebesar 5,946%; dan pada bahan bakar B22,5 torsi meningkat sebesar 1,885%. Perubahan daya yang dihasilkan pada bahan bakar B17,5 menurun sebesar 0,634%; pada bahan bakar B20 daya meningkat sebesar 2,902%; dan pada bahan bakar B22,5 daya meningkat 2,310%. Terjadi Penurunan konsumsi bahan bakar pada bahan bakar B17,5 sebesar 21,07%; pada bahan bakar B20 menurun sebesar 12,68%; dan pada bahan bakar B22,5 menurun sebesar 21,43%. Opasitas gas buang yang dihasilkan mengalami penurunan yaitu pada bahan bakar B17,5 sebesar 34,73%; pada bahan bakar B20 sebesar 31,30%; dan pada bahan bakar B22,5 sebesar 31,95%. Kata kunci: biodiesel, virgin coconut oil, solar, unjuk kerja mesin, opasitas

PENGARUH VARIASI LAMA PENGERINGAN DAN VOLUME LARUTAN GRAPHENE OXIDE BERBAHAN DASAR ABU SEKAM PADI TERHADAP KUAT TEKAN DAN POROSITAS BATA RINGAN JENIS CELLULAR LIGHTWEIGT CONCRETE

Penelitian ini bertujuan untuk memperoleh sintesa graphene oxide (GO) dari bahan abu sekam padi dengan metode liquid sonification exfoliation (LSE) menggunakan tweeter ultrasound graphene oxide generator (TUGG), mengetahui pengaruh penambahan volume GO pada bata ringan terhadap porositas dan kuat tekannya, dan mengetahui pengaruh lama pengeringan bata ringan GO terhadap kuat tekan yang dihasilkan. Karakterisasi dan sintesa GO berbahan abu sekam padi menggunakan spektrofotometer UV-Vis dengan melihat puncak absorbansi pada daerah panjang gelombang 230-270 nm. Penelitian ini diawali dengan membuat larutan surfaktan yang dicampur abu sekam padi dimana larutan dibuat dengan variasi konsentrasi abu sekam padi 0,005 gr/ml; 0,01 gr/ml; 0,015 gr/ml; 0,02 gr/ml; dan 0,025 gr/ml. Sampel disintesis dengan metode LSE menggunakan TUGG selama 5 jam kemudian didiamkan semalam agar beberapa lapis GO terpisah dari kumpulan lapisan abu sekam padi. Sampel GO abu sekam padi diuji menggunakan spektrofotometer UV-Vis untuk mengetahui adanya lapisan GO. Kemudian larutan GO abu sekam padi dicampurkan ke dalam air, pasir semen, dan foam. Kemudian bata ringan dicetak dengan ukuran (5×5×5) cm3 lalu dikeringkan. Proses pengeringan dilakukan menggunakan dua cara yaitu secara alami dan menggunakan oven. Bata ringan yang dihasilkan kemudian diuji porositas dan kuat tekannya untuk mengetahui pengaruh penambahan volume GO dan lama pengeringan terhadap kualitas bata ringan tersebut. Hasil UV-Vis GO abu sekam padi menunjukkan bahwa konsentrasi 0,025 gr/ml menghasilkan GO dengan jumlah paling banyak dibandingkan konsentrasi lainnya. Penambahan volume larutan GO abu sekam padi berpengaruh terhadap porositas bata ringan namun secara signifikan menambah kuat tekan dari bata ringan tersebut. Porositas bata ringan bertambah karena surfaktan pada larutan GO menambah jumlah foam. Kuat tekan bata ringan menjadi lebih tinggi karena GO memperkuat struktur pori-pori pada bata ringan. Pada proses pengeringan alami, kuat tekan tertinggi diperoleh pada penambahan volume GO 50 ml dengan nilai 7,31x106 N/m2 yang menghasilkan porositas 38,08 % dan berat 134,64 gram. Sedangakan pada proses pengeringan dalam oven kuat tekan tertinggi terdapat pada lama pengirangan 4 jam dengan kuat tekan sebesar 1,23x106 N/m2

Profil Tokoh Remaja Minangkabau Dalam Cerpen-cerpen Remaja Harian Umum Singgalang Minggu

This study aimed to describe the profile in terms of adolescent Minangkabau outlook on life, responsibility, love, beauty, suffering and ideals of the juvenile short stories published by Daily Singgalang Sunday. Data were collected by means of : (1) read and understand short stories teen Singgalang daily publications Sunday, this is done to obtain a clear understanding of the profile of the studied adolescents , (2) record the speech and text can be abstracted as a teenager with profile data use a table format. Based on the research results, it can be concluded that the profile of adolescents in juvenile short stories published by daily Singgalang Sunday, has a live view of the ideal form of self behaved , responsible , family and love for the opposite sex , is able to conclude a beauty and also have pain. From the discussion, it can be seen, the profile figure in Minangkabau teen teen short story published Sunday daily Singgalang have a view of life that is included in the category of idealism, pragmatism and materialism

A New Chaotic System with a Pear-shaped Equilibrium and its Circuit Simulation

This paper reports the finding a new chaotic system with a pear-shaped equilibrium curve and makes a valuable addition to existing chaotic systems with infinite equilibrium points in the literature. The new chaotic system has a total of five nonlinearities. Lyapunov exponents of the new chaotic system are studied for verifying chaos properties and phase portraits of the new system are unveiled. An electronic circuit simulation of the new chaotic system with pear-shaped equilibrium curve is shown using Multisim to check the model feasibility

KAJIAN KANDUNGAN SENYAWA PHENOL DAN SENYAWA PAH PADA ASAP CAIR CANGKANG KELAPA SAWIT (ACCKS) REDESTILASI YANG DIHASILKAN PADA TEMPERATUR TINGGI

Pyrolysis process is carried out in this study using a furnace, the temperature is set ranging from 600,700,800,900 ᵒ C using condenser cooling spiral type. Liquid smoke oil palm shell (ACCKS) produced centrifuge with speed 380 rpm for 30 min, filtered through filter paper and distilled at a temperature of 125 ᵒ C for 20 minutes ACCKS redestilasi analyzed the content of the compound phenol compound and polycyclic aromatic hydrocarbons (PAH) using a GCMS.To temperatures of 600 to 900ᵒC was not identified PAH compounds and the higher the temperature the lower the phenol compounds whereas the higher acetic acid compounds.Keuwords: ACCKS redestilation, phenol content, PAH, quality

MODIFIKASI KIMIA KARET ALAM SIKLIS (CYCLIC NATURAL RUBBER/CNR) DENGAN TEKNIK GRAFTING: MENGGUNAKAN MONOMER METIL METAKRILAT DAN INISIATOR BENZOIL PEROKSIDA

AbstractThe research of grafting methyl methacrylate (MMA) onto Cyclic Natural Rubber (CNR) has been carried out. Benzoyl Peroxide (BPO) was used as a inisiator and temperature condition at 90oC with variation of time 1 and 2 hours. Grafting process was done with technique of reflux in a tree-neck flask  with condenser and oil bath. Spectra analysis FTIR performed for determine the presence of grafted MMA on the backbone of CNR. The results showed that the product CNR-g-MMA was formed with the marked appearance of the absorption peak wave numbers at 1731 and 1730 cm-1 (carbonyl group absorption) typical for carbonyl (C = O) of metal methacrylate. The degree of grafting increased with the increasing time grafting.Keywords: grafting, cyclic natural rubber, mathylmetacrilate, benzoyl peroxid

Syncope: experience at a tertiary care hospital in Karachi, Pakistan

Introduction:Our aim was to determine the characteristics of Patients presenting with syncope at a tertiary care hospital in Karachi, Pakistan.Methods: A review of medical records was conducted retrospectively at the Department of Medicine, Aga Khan University Hospital, Karachi. Patients aged 16 and above, admitted from January 2000 to December 2005 with the diagnosis of syncope made by the attending physician were included.Results:A total of 269 Patients were included (75% males, mean age: 57.4 years). Neurogenic (vasovagal) syncope was the most common cause (47%), followed by cardiogenic syncope (18%) and orthostatic syncope (9%). A total of 24% were discharged undiagnosed. Twenty Patients (7.4%) did not have any prodrome. Common prodromal symptoms included dizziness (61%), sweating (25%), palpitations (19%), nausea/vomiting (19%) and visual symptoms (17%). The distribution of symptoms according to cause of syncope revealed only breathlessness to be significantly associated with cardiogenic syncope (p = 0.002). Most Patients with cardiogenic syncope were aged above 40 (98%, p \u3c 0.001), had coronary artery disease (72%, p \u3c 0.001) and abnormal electrocardiogram at presentation (92%, p \u3c 0.001).Conclusion:Despite differences in burden of diseases, our findings were similar to those of published syncope literature. Further studies are needed to develop a protocol to expedite the evaluation and limit the work-up and admission in low-risk Patients

A text criticism of Hikayat Si Miskin: A textological study of writing and use of letters

This research aim to describe a textological study of the issue of how the Hikayat Si Miskin manuscript text from the Harvad University - Houghton Library/ ms_Indo_18-METS collection was translated into handwritten Arabic-Malay script, the appearance of which is much different from the standard form of the letters of this script. This is the most important part in the textological study of the subfield of philology before the editing of texts from the old Malay Arabic-Malay script into Latin script is presented. His identity as the author is not included at the front of his work, but at the end of the manuscript called the colophon. The presentation of a text that has been cleaned of all writing errors paves the way for further study of the content of the text from various aspects related to the existence of the form and content of the text being studied, such as a study of the structural content of the text, a study of linguistic aspects, a study of social values. and culture, it is even possible to examine historical elements, because manuscripts are historical documents that describe the life systems and patterns of old society. The method used to discuss text issues and content that can be studied in various related scientific disciplines is the standard text criticism method, namely a philological method that attempts to re-present classical texts by criticizing and correcting corrupt texts. In accordance with the focus of the discussion which focuses on writing and visual text writing, the research results found writing irregularities and errors in writing lacunae, substitutions, additions, transpositions, dittography, and haplography. The most common writing errors are substitution errors