1,720,962 research outputs found
Produksi Bahan Bakar Cair Dari Limbah Plastik Polypropylene (PP) Metode Pirolisis
Full text linkProduksi dan konsumsi plastik meningkat setiap tahunnya. Olehnya itu perlu dilakukan pemanfaatan plastik khusunya plastik Polypropylene (PP) melalui metode pirolisis menghasilkan bahan bakar minyak (BBM). Hal ini merupakan alternatif untuk dapat menanggulangi pesatmya jumlah pemakaian bahan bakar minyak (BBM) dan konsumsi plastik. Penelitian ini bertujuan untuk menghasilkan bahan bakar alternatif dengan mengetahui temperatur dan waktu tinggal dari minyak. Metode perlakuaan thermal yaitu pirolisis, dimana bahan yang digunakan yaitu plastik bekas kemasan gelas, dengan variasi suhu 200oC,250 oC,300 oC,350oC,400oC dan 450oC. Yield terbanyak yang didapat dari pirolisis variasi suhu di pirolisis kembali untuk mendapatkan waktu optimum variasi waktu 5,10,15,20,25 dan 30 menit. Hasil penelitian disimpulkan limbah plastik jenis PP metode pirolisis dapat dihasilkan bahan bakar minyak yang setara dengan bensin. Suhu proses yang dihasilkan 400oC yield 79,85% sedangkan waktu optimum 25 menit yield 72,19%. Hasil diperoleh 0,7542 gram/ml untuk uji densitas, 11.621,4 kal/gram untuk uji nilai kalor dan 29,91% area diperoleh kadar senyawa hidrokarbon 2,4-dimethyl-1-heptene (C9H18) pada pengujian komponen senyawa kimia di alat GC-M
Microwave Assisted Hydrodistillation Essential Oil from Lime Peel Waste as Aromatherapy Candles
Full text linkFlavonoids belong to the extensive group of polyphenol compounds. They can function as antioxidants and antibacterials by denaturing bacterial cell proteins and damaging bacterial cells. One source of essential oils is lime peel, which is often discarded and goes unused. The distillation method utilizes microwaves, offering an alternative to conventional distillation techniques and resulting in enhanced effectiveness and efficiency. The Microwave Assisted Hydrodistillation (MAHD) method proves to be more energy-efficient, environmentally friendly, rapid, safe, and cost-effective. This study aims to assess the impact of the MAHD method on the quantity and quality of essential oils extracted from lime peels. Laboratory tests are conducted in accordance with Indonesian national standards. The overarching objective is to establish a process that transforms discarded lime peels into aromatherapy candles, contributing to respiratory health. The MAHD method is employed with a sample mass to distilled water solvent ratio of 1:1. The resulting essential oil undergoes analysis using the GC-MS method. According to the GC-MS test results, the compound with the highest percentage area is limonene at 98%. This is followed by trans-caryophyllene at 99% with a retention time of 12.422, and beta-selinene at 99% with a retention time of 13.191
Penentuan Kadar Logam Zn dan Pb Pada Bendungan Lekopancing
Full text linkLimbah pada dasarnya adalah suatu bahan yang terbuang atau dibuang dari suatu sumber hasil aktivitas manusia, (domestik) dalam melaksanakan suatu proses produksi biaanya menghasilkan zat buangan yang sering disebut sebagai limbah. Seng (Zn) merupakan logam esensial yang keberadaannya dalam jumlah tertentu dibutuhkan oleh organisme hidup, namun dalam jumlah yang berlebihan dapat menimbulkan efek toksik. Kadar logam Zn yang tinggi akan mempengaruhi kesehatan manusia antara lain keracunan (muntah), kerusakan usus, penuaan dini hingga kematian mendadak, radang sendi, cacat lahir, gusi berdarah, kanker, kanker, sirosis, sembelit, diabetes, diare, pusing, kelelahan., hepatitis dan insomnia (Ribka, Junita Sembiring, 2021). Timbal atau logam berat di lingkungan laut dapat di kategorikan sebagai logam berat esensial dan non esensial. Salah satu logam berat yang mempunyai sifat non esensial adalah timbal (Pb). Penelitian ini bertujuan untuk mendapatkan informasi mengenai kandungan logam Pb dan Zn pada bendungan lekopancing kabupaten maros, serta mengetahui tingkat pencemaran logam tersebut di Perairan bendungan lekopancing, metode yang digunakan dengan penentuan kadar Zn dan Pb dengan menuangkan sekitar 75 ml sampel air bendungan kedalam Erlenmeyer yang sebelumnya disaring, kemudian penentuan cara kerja alat instrument metode flame, Dari hasil penelitian dapat disimpulkan bahwa kadar logam Zn dan Pb pada bendungan lekopancing dengan menggunakan metode SSA (spektrofotometer serapan atom) baik sampel input dan output adalah 0% atau tidak terdeteksi dan dapat juga disimpulkan bahwa Air Bendungan Lekopancing Aman digunakan ataupun dikomsumsi oleh masyarakat sekitar
Effect of Liquid Smoke from Pyrolysis of Durian Skin and Etanol Extract of Orange Peel as Bio Hand Sanitizer
Full text linkLiquid smoke resulting from pyrolysis of durian skin has antibacterial potential which is used as a basic ingredient for making bio hand sanitizer. Durian skin is difficult to degrade because it contains high levels of lignin, cellulose, and hemicellulose compounds, so with the use of durian skin, it is expert that it will be able to reduce durian skin waste. Bio hand sanitizer is formulated with essential oils to reduce the pungent aroma of smoke. This study aims to determine the antibacterial activity and characteristics of the durian skin liquid smoke bio hand sanitizer. This study used the Completely Randomized Design (CRD) method, with a comparison between durian peel liquid smoke and orange peel extract and the addition of 10 mL NaOH (1:3, 1:1,57, 1:1, and 3:1). The results of research based on characteristic tests obtained pH values of 4.81-7.36, viscosity 1392-3664 cps. Formula E (3:1) emerged as the best sample through organoleptic tests on each bio hand sanitizer preparation formula. It exhibited a yellow color, a runny texture, and a smoky aroma with the mixture. The antibacterial test demonstrated that the bio hand sanitizer preparation possessed antibacterial activity, and the resistance diameter for the test bacteria S. Aureus and E. Coli ranged from 21.51 to 31.14 m
Treatment of Eceng Gondok Waste into Electrical Based on Microbial Fuel Cell
Full text linkThe increasing consumption of electrical energy and still dependent on non-renewable energy has encouraged the implementation of effective, efficient, and environmentally friendly technologies to produce electrical energy. Microbial Fuel Cell (MFC) is one of the alternative technologies that utilize microorganisms in converting chemical energy from organic compounds under anaerobic conditions to be converted into electrical energy.  The study was conducted to determine the potential of electrical energy generated from the treatment of eceng gondok waste (Eichhornia crassipes) with variations in the addition of buffer solutions and combinations of electrolyte solutions using the microorganism Saccharomyces cerevisiae through Microbial Fuel Cell technology. This study consists of three stages and methods, namely sample preparation, MFC media preparation, and analysis of pH, current, voltage, and power density. Measurement of the value of the maximum voltage, maximum current and power density is carried out every 3 hours for 27 hours for each treatment. The results were obtained as follows consecutively: firstly, for variations without the addition of buffers and electrolyte solutions are 0.25 volts; 0.08 mA; 13.05 mW/m2, secondly, with buffer and electrolyte solution KMnO4 0.2 M are 1.12 volts; 0.77 mA; 562.92 mW/m2, and thirdly, with buffer and K3Fe(CN)6 0.2 M are 0.47 volts; 0.48 mA; 147.26 mW/m2. Based on the results of the study, it was concluded that the most optimal variation in producing electrical energy was in the variation in the addition of a phosphate buffer and 0.2 M KMnO4 solution.  Eceng gondok waste has the potential to be used as a source of electrical energy
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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