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PENGANTAR REAKSI Kusumayanti, Heny
METANA Vol 6, No 01 (2009): April 2009
Publisher : Universitas Diponegoro

PENGANTAR REDAKSI

Kesetimbangan Adsorpsi Zat Warna Methyl Violet Oleh Karbon Aktif Berbasis Limbah Daun Nanas (Ananas comosus L) Lanjar, Lanjar; Riayanti, Fatma Indah; Astuti, Widi
METANA Vol 14, No 2 (2018): Desember 2018
Publisher : Universitas Diponegoro

Industri tekstil semakin berkembang seiring dengan pertumbuhan penduduk di Indonesia. Selain memberikan manfaat, industri tekstil Â memberikan dampak negatif bagi lingkungan akibat penggunaan zat warna sintetis, salah satunya yaitu methyl violet. Apabila limbah tersebut dibuang ke perairan akan menyebabkan rusaknya ekologi lingkungan dan ancaman bagi kesehatan manusia, karena sebagian besar zat warna bersifat sukar terurai (non-bidegradable) dan karsinogenik (Brono, 2010). Salah satu metode yang terbukti efektif untuk menghilangkan zat warna adalah adsorpsi menggunakan karbon aktif. Pada penelitian ini karbon aktif dibuat dari limbah daun nanas dengan aktivator ZnCl2 dan pemanasan gelombang mikro. Selanjutnya, karbon aktif tersebut dikarakteriasi morfologi permukaan menggunakan Scanning Electron Microscopy (SEM), luas permukaan menggunakan Surface Area Analyzer, dan analisis gugus fungsi menggunakan Fourier Transform Infrared (FTIR) spectrometer, dan digunakan untuk menjerap methyl violet di larutan. Hasil penelitian menunjukkan bahwa karbon aktif dari limbah daun nanas yang teraktivasi ZnCl2 menghasilkan pori yang lebih besar dibandingkan dengan karbon tanpa aktivasi serta memiliki gugus fungsi yang dapat menjerap methyl violet. Kondisi optimum untuk adsorpsi adalah pH 5, waktu kontak 90 menit, dan konsentrasi awal 500 mg/L. Model kesetimbangan yang sesuai yaitu menggunakan model isotherm freundlich.

EKSTRAKSI FLAVONOID DARI DAUN PARE (MOMORDICA CHARANTIA L.) BERBANTU GELOMBANG MIKRO SEBAGAI PENURUN KADAR GLUKOSA SECARA IN VITRO Mutiara, Erlita Verdia; Wildan, Achmad
METANA Vol 10, No 01 (2014): Juli 2014
Publisher : Universitas Diponegoro

Abstract One of the traditional medicinal plants are believed to be lowering glucose levels are pare (Momordica charantia L.). Plants pare (Momordica charantia L.) is a plant that is familiar to the people of Indonesia, because the fruit is often used as asvegetables. The pare leaf chemical constituents is alkaloids, flavonoids, saponins, and tannins that can be used as an antioxidant, antimicrobial, antidiabetic, antitumor, and antilepra. The main advantage of microwave-assisted extraction compared to conventional extraction using soxhlet namely greater efficiency and a shorter operating time. Microwave-assisted extraction will provide the transfer rate is higher than the conventional extraction. This study aims to determine the ability of a flavonoid extract of the leaves of pare (Momordica charantia L.) in lowering glucose levels and maximum concentrations of the extract flavonoids that can lower glucose levels as well as the variation of the variable microwave extraction for obtaining extracts optimal results. The process of extracting flavonoids from the leaves of pare (Momordica charantia L.) is done using a microwave extractor with frequency 2450 MHz with a maximum power of 900 watts. The extract obtained was then reacted with glucose with Nellson-Somogyi method. Types of flavonoids that play a role in lowering glucose levels were identified using a sliding reagent with UV-Vis spectrophotometer. The results showed that the optimum conditions in the extraction process of flavonoids from the leaves of bitter melon (Momordica charantia L.) by microwave-assisted was the 30 minute with a yield of 20.85%. The concentration of flavonoids extract can lower glucose levels are 160 ppm with a 50.38% decrease. Flavonoid compounds that play a role in lowering glucose levels in the leaves of pare is 5,3 ', 4'-trihydroxy flavonols. Keywords: extraction, microwaves, glucose, pare leaves, Nellson Somogyi Abstrak Salah satu tanaman obat tradisional yang dipercaya sebagai penurun kadar glukosa adalah pare (Momordica charantiaL.). Tanaman pare (Momordica charantia L.) merupakan tanaman yang tidak asing bagi masyarakat Indonesia, karena buahnya sering digunakan sebagai sayuran atau lalapan. Kandungan kimia daun pare yaitu alkaloid, flavonoid, saponin, dan tanin yang dapat digunakan sebagai antioksidan, antimikroba, antidiabetes, antitumor, dan antilepra.Keuntungan utama dari ekstraksi dengan bantuan gelombang mikro dibandingkan dengan ekstraksi konvensional menggunakan sokhlet yaitu efisiensi lebih besar dan waktu operasinya lebih singkat. Ekstraksi berbantu gelombang mikro akan memberikan laju perpindahan masa yang lebih tinggi dibandingkan ekstraksi konvensional. Penelitian ini bertujuan untuk mengetahui kemampuan dari ekstrak flavonoid dari daun pare (Momordica charantia L.) dalam menurunkan kadar glukosa dan konsentrasi maksimal dari ekstrak flavonoid yang dapat menurunkan kadar glukosa serta variasi dari variabel ekstraksi gelombang mikro untuk memperoleh hasil ekstrak yang optimal. Proses ekstraksi flavonoid dari daun pare(Momordica charantia L.) dilakukan menggunakan alat microwave ekstraktor dengan frekuensi 2450 Mhz dengan daya maksimal 900 watt. Ekstrak yang diperoleh kemudian direksikan dengan glukosa dengan metode Nellson-Somogyi. Jenis flavonoid yang berperan dalam menurunkan kadar glukosa diidentifikasi menggunakan pereaksi geser dengan spektrofotometer UV-Vis.Hasil penelitian menunjukkan kondisi yang optimum dalam proses ekstraksi flavonoid dari daun pare (Momordica charantia L.) dengan berbantu gelombang mikro adalah menit ke-30 dengan rendemen 20,85%. Konsentrasi ekstrak flavonoid yang dapat menurunkan kadar glukosa adalah 160 ppm dengan penurunan 50,38%.Senyawa flavonoid yang berperan dalam menurunkan kadar glukosa dalam daun pare adalah 5,3â€™,4â€™-trihidroksi flavonol. Kata kunci : Ekstraksi, gelombang mikro,glukosa, daun pare, Nellson Somogyi

PERKUATAN ( STRENGTHENING) STRUKTUR BETON DENGAN FIBER REINFORCED POLYMER (FRP) Christiawan, Ignatius
METANA Vol 6, No 01 (2009): April 2009
Publisher : Universitas Diponegoro

Abstract Â In effort fulfill requirement the well building infrastructure, safety of building user such as building avalanche damage as result of earthquake is principal priority. Load addition on building exceeds the planning load as result of the involuntary building function change always generating the building avalanche damage. It was needed evaluate to the strength of building structure at the existing condition and strengthening if it was needed before the structure given the new load. One of the strength procedure is external reinforcement method especially give Fiber Reinforced Polymer (FRP) that it was adhered on the concrete component surface which reinforced by epoxy glue. From several former researches, base analysis and bent planning along with example of the practice calculation of beam strength by FRP can be concluded that the use of FRP in combination with the others strength method is easy and practice for conducted and also capable to increase the strength of concrete beam bent. Â Kcywords: load addition, strength, safety

MICROANALYSIS PEMBENTUKAN KRISTAL CALSIUM SULFAT PADA PIPA BERALIRAN LAMINER DENGAN PARAMETER LAJU ALIR Mangestiono, Wiji
METANA Vol 7, No 01 (2011): Juli 2011
Publisher : Universitas Diponegoro

Abstract Â Gypsum (CaSO4. 2H2O) scaling inside pipe is very problematic for industries since it causes narrowing of pipe diameter, thickening of heat transfer surfaces, lenghthening the process time and finally increase the cost of production. It is therefore necessary to prevent the occurance of gypsum scaling in a piping system. This report describes an experiment on gypsum scale formation utilizing CaCl2.2H2O and Na2SO4 solutions to form gypsum ( CaSO4. 2H2O). The concentration the calcium ions selected was 3,500 ppm. The experiment was carried out a pipe with several coupons made of copper representing common pipe material used in industry. Flowrate of gypsum solution as one of process parameters for gypsum scaling was varied: 30, 40 andÂ 50 ml/minuteÂ respectively. In addition, Cu2+ as impurities was aded into the solution : 5 and 10 ppm respectively. In adition, a microanalysis on the scale was also caried out using EDAX. The mass of the scale formed was calculated in order to determine the rate of the gypsum scale growth. Keywords : flowrate, gypsum, impurities, piping system.

KONSENTRASI LOGAM BERAT DI PERAIRAN, SEDIMEN DAN BIOTA DENGAN FAKTOR BIOKONSENTRASINYA DI PERAIRAN BATU BELUBANG, KAB. BANGKA TENGAH Wahyuni, Hasti; Sasongko, Setia Budi; Sasongko, Dwi P
METANA Vol 9, No 02 (2013): Desember 2013
Publisher : Universitas Diponegoro

Abstract Â The reduction of land that used for land-based mining caused the shift of mining from land-based mining to off-shore mining, that used to namedFloating Inkonvensional Mining. This type of mining caused waters quality degradation.This research aimed to analyze Pb, Cd, and Zn content in water, sediment, and biota so that the value of the bio-accumulation factor can beanalyzed.The locations determination was conducted by using purposive random sampling method and the implementation was using GPS Garmin 60 in June 2013. The sea water sampling was using the water sampler, the sediment sampling was using paralon pipe, the plankton sampling was using the plankton-net, the shellfishes sample was collected from the fishermen, and the chavies and squids sample was got from Baganin the waters of Pulau Panjang.The analysis of the metal in water and sediment was refer to the prosedur standard method (APHA, 2005), while the analysis of the heavy metal in the planktons and the tissue of the biota was refer to SNI 2354.5:2011. The content of metal was compared with the quality standard that have been determined.The Cd and Zn content in water was under the sea water quality standard for sea biota. The Pb in the waters have been exceeded the quality standard that have been determined in Kepmen LH no. 51 Tahun 2004.The Pb, Cd, and Zn content in sediment wasÂ lower and far away from the quality sandard that have been determined by Norwegia and Irlandia. The heavy metal content in Anadara granosa, Stolephorus, sp, and Loligo chinensis, gray which were got chaught in the waters of Batu Belubang was lower thanthe national quality standard (SNI 2731.1:2010). The value of bio-concentration factor (BCFs-w) showed that the highest ability of sediment to accumulate Pb was existed in station number 2, i.e. 10,037 l/kg. The value of bio-concentration factor (BCFo-s) showed the plankton ability to accumulate Pb in sediment (1,26) was higher than its ability to accumulate Zn in sediment (1,22), while its ability to accumulate metal in water (BCFo-w) was as high as 8,275 in station number 2. The value of bio-concentration factor (BCFo-s) showed that the shellfish, chavies, and squid ability in accumulating metal in sediment was as high as 0,713; 0,564 and 0,703. The value of bio-accumulation of shellfish in sediment was higher because sediment was the habitat of shellfish.Floating Inkonvensional Mininghave contribution in spreading heavy metal, that was contained in the soil, to the waters. This condition needs supervision to control TI Apung growth in this location so that does not pollute the waters. Kata kunci : Lead(Pb), Cadmium (Cd), Zink (Zn), Water, Sediment,Plankton, Shellfish, Chavies,Squid, Batu Belubang, Floating Inkonvensional Mining, Bio-concentration Factor (BCF). Â

OPTIMASI WAKTU PERENDAMAN DAN KONSENTRASI NATRIUM METABISULFIT PADA PROSES PRODUKSI TEPUNG SUKUN Kusumayanti, Heny; Faizah, Laila; Broto, R TD. Wisnu
METANA Vol 10, No 02 (2014): Desember 2014
Publisher : Universitas Diponegoro

Abstract The breadfruit plants were included in the tribe Moraceae produce breadfruit. Breadfruit can be used and consumed by the public into processed foods for a snack, can be in the form of fried breadfruit, boiled breadfruit, gethuk breadfruit. To overcome the breadfruit harvest time, and to extend the shelf life of breadfruit, breadfruit then can be made into other processed food products, including breadfruit can be processed into flour breadfruit. Breadfruit flour can be made using raw materials made breadfruit chips of a certain size, then the chips is soaked with a solution of natrium Â metabisulphite with various concentrations and soaking time varies. In immersion chip by using solution of natrium metabisulphite 0,8 % yield breadfruit flour carbohydrate 25.87% with a soaking time 55 minutes. Key Words: breadfruit, breadfruit flour Abstrak Tanaman sukun yang termasuk dalam suku Moraceae menghasilkan buah sukun. Buah sukun dapat dimanfaatkan serta dikonsumsi masyarakat menjadi makanan olahan untuk camilan, bisa dalam bentuk sukun goreng, sukun rebus, gethuk sukun. Untuk mengatasi waktu panen raya sukun, dan untuk memperpanjang umur simpan buah sukun, maka buah sukun bisa dibuat menjadi produk olahan pangan yang lain, diantaranya buah sukun tersebut dapat diolah menjadi tepung sukun. Tepung sukun dapatÂ dibuat dengan menggunakan bahan baku buah sukun yang dibuat chip dengan ukuran tertentu, selanjutnya chip tersebut direndam dengan menggunakan larutan natrium metabisulfit dengan berbagai konsentrasi dan waktu perendaman yang bervariasi. Pada perendaman chip dengan menggunakan larutan natrium metabisulfit 0,8 % menghasilkan tepung sukun dengan kadar karbohidrat 25,87 % dengan waktu perendaman 55 menit. Key Words : buah sukun, tepung sukun

STUDI AWAL REKAYASA PROSES PRODUKSI TEH HIJAU BERKATEKIN TINGGI MELALUI TEKNOLOGI STEAMING Yulianto, Mohammad Endy; Senen, Senen; Ariwibowo, Didik
METANA Vol 4, No 1 (2007): Juni 2007
Publisher : Universitas Diponegoro

Abstract Tea is a nalural healty, beverage because of catechin content which is a bioactive matter that can retard cancel growth, heart desease, blood and nerves, making healthy for mouth, teeth and some other infection. Therefore, high catechin in tea would be needed. To Obtain high catechin contend it must eliminate enzymatically oxidation process of polyphenol during tea manufacturing. Thus, it was created a process and processing system which sustain the process. The basic design was inactivation of polyphenol oxidase enzyme by steaming. It wishes a high catechin green tea product that can either be directly as a beverage or as a catechin powder for dietary food and functional food or medicine. The variables of this study, were percentage of steam, tea leaves feeding and humidity. The investigated parameters were temperature, catechin content, moisture content, and humidity as time function. The result was that at 900C yielded high catechin. The study shows that at 70%Â humidityÂ yielded higher catechin and lower moisture content. Â Keywords : Green tea; Steaming

Gas SF 6 (Sulfur Hexa Fluorida) Sebagai Pemadam Busur Api Pada Pemutus Tenaga (PMT) Di Saluran Transmisi Tegangan Tinggi Setiono, Iman
METANA Vol 13, No 1 (2017): Juni 2017
Publisher : Universitas Diponegoro

Keberadaan Pemutus Tenaga (PMT) pada saluran transmisi mutlak diperlukan, karena untuk menyalurkan dan memutuskan sistem penyaluran tenaga listrik dari pusat pembangkitan sampai ke konsumen harus bisa di atur dengan menggunakan PMT ini. PMT adalah sebuah alat yang berfungsi untuk memutus-hubungkan aliraan listrik yang melalui saluran transmisi tegangan tinggi. Karena faktor tegangan tinggi , yaitu untuk Saluran Udara Tegangan Tinggi (SUTT)Â adalah 150 KV dan untuk Saluran Udara Tegangan Extra Tinggi (SUTET) adalah 500 KV, maka setiap kali menghubungkan dan memutuskan kontak di dalam PMTÂ gesekan pada kontak-kontak tersebut yang terbuat dari logam. Akibat dari gesekan ini akan muncul bunga api yang sangat berbahaya dapat menimbulkan kebakaran dan kerusakan peralatan. Untuk memadamkan bunga api ini , maka di gunakan gas SF6 yang bersifat isolator , sehingga bunga api padam dan dapat mencegah terjadinya kebakaran dan kerusakan peralatan.Â Â Gas SF6 (Hexa Fluoride Sulfur) As Fire Extinguisher On Power Breaker (PMT) On High Voltage Transmission ChannelÂ The existence of Power Circuit breaker (PMT) in the transmission line is absolutely necessary, because to channel and decide the system of electricity distribution from the power stationÂ to the consumer must be managed by using this PMT. PMT is a device that serves to break-up the electricity supply through high voltage transmission lines. Due to the high voltage factor, that is for High Voltage transmission line (SUTT) is 150 KV and for Extra High Voltage Transmission line (SUTET) is 500 KV, then every time connect and disconnect the contact inside the friction PMT on those contacts made from metal. As a result of this friction will appear very dangerous sparks can cause fire and equipment damage. To extinguish this spark, then in use SF6 gas that is an isolator, so the sparks out and can prevent the occurrence of fire and equipment damage.

PENGARUH ARUS DAN WAKTU PADA PELAPISAN NIKEL DENGAN ELEKTROPLATING UNTUK BENTUK PLAT Sutomo, Sutomo -; Senen, Senen -; Rahmat, Rahmat -
METANA Vol 6, No 02 (2010): Desember 2010
Publisher : Universitas Diponegoro

The influence of electric current and time using to coating production with electroplating machine for flat forming. Corrosion is the mainly problem of material, base on this problem researcher would like to know the influence of nickelâ€™s mass for plat coating. This research have conclusion that more time the electric current is needed will produce more thickness of coating. The current is 4 amperes and the time is 2400 seconds will produce 1.8 gr nickelâ€™s coating. Increasing current density will increase the thickness of coating, especially for using time 2400 seconds, current density 8.5 amperes/dm2. Layering rate of coating is 1.0 Î¼m/second for current density A/dm2 Key word : electroplating, electric current, time coating

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