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Jurnal Matematika dan Ilmu Pengetahuan Alam
Published by Universitas Airlangga
ISSN : -     EISSN : -     DOI : -
Core Subject : Education,
Mathematics
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Articles 8 Documents
 1 
Search results for , issue " Vol 17, No 1 (2015)" : 8 Documents clear
Penentuan Kondisi Optimum Penyerapan Logam Kadmium Oleh Asam Humat Darmokoesoemo, Handoko; Setyawati, Harsasi
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

This research was study on the formation of complexes between metals Cd(II) with humic acid and the optimum conditions of metal Cd(II) adsorption by humic acid. Determination of optimization conditions of metal Cd(II) adsorption by humic acid i.e. variation of contact time, pH and Cd(II) concentration. The results showed the optimum contact time was 90 minutes with a percentage of Cd adsorped was 86.52%, the pH optimum was pH 6 with a percentage of Cd adsorped was 80.39% and the optimum Cd(II) concentration was 500 ppm with the optimum Cd(II) adsorped by humic acid was 221, 8 mg /L. FTIR analysis showed the presence a bond between the metal Cd(II) with oxygen groups of humic acid at wavelength of 354.90 cm-1. The adsorption model of Cd(II) by humic acids showed Langmuir type with correlation coefficient 0,99909.Keywords : humic acid, cadmium, Cd(II)-humat complexes.
Kajian Proses Sintering pada Metode Metalurgi Serbuk Paduan Kobalt Sebagai Kandidat Material Implan Tulang Aminatun, Aminatun
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

This study aimed to find out the optimum sintering temperature and time on the powder metallurgy method to produce cobalt alloy as candidate bone implants material. The quality of the metal alloy of the metallurgi method is determined by the temperature and time of sintering, resulting in the selection of these two parameters will be generated alloy which has a crystal structure as expected with better mechanical properties along with the crystal structure. The sintering process used powder metallurgy method with composition of 63.75 % Co - 30 % Cr - 5 % Mo - 0 , 5 % Mn - 0 , 5 % Si - 0 , 25 % N adjusted to ASTM F75. The initial step is all the ingredients of the milling process were mixed at a speed of 350 rpm for 15 minutes. Furthermore, powder was compressed with 21 MPa pressure at 200°C with 10 minutes holding time in the form of pellets with diameter of 1.5 cm. The pellet was sintered with temperature variations of 1100 ºC, 1200 ºC and 1300 ºC for 2 hours holding timeeach, and at a temperature of 1300 ºC with a variation of 1 hour and 3 hours holding time. The results showed that the crystal structure of the cobalt alloy contained 3 phase, which are phase γ (FCC), phase ɛ (HCP), and σ phase (tetragonal). γ phase appears at a temperature of 1300ºC with 1 and 2 hours holding time. The emergence of this γ -phase led to the increase of cobalt alloy hardness value, because γ –phase is a stable phase with a density greater than the other phases. The highest hardness value of 304.7 ± 9.0VHN with the largest γ-phase fraction (34.9 %) was obtained at a sintering temperature of 1300 ºC with 2 hours holding time. SEM - EDX test results indicated that cobalt alloys still contain pores or cavities with the uneven elements distribution and oxidation occurs. Based on these results it can be concluded that the sintering temperature of 1300 ºC with 2 hours holding time is the optimal sintering temperature and time to produce a cobalt alloy which has potential as bone implant material in terms of hardness value.Keywords: cobalt alloy, powder metallurgy, sintering
Struktur Komunitas Teripang di Pantai Timur Surabaya Winarni, Dwi
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

The objectives of this research were to obtain diversity, relative abundance, distribution, and habitat preference of sea cucumber species along east Surabaya coastal. Identification, data distribution, relative abundance and habitat preference of sea cucumbers were observed at 12 sites along Surabaya east coastal. Parameters to describe environment were water depth, brightness level of water, pH (water and substrate), salinity (water and substrate) and the texture of substrate. The texture of substrate was determined based on particles diameter of substrate (ASTM method). The research revealed that during September 2009 until October 2010, physical and chemical parameters of environment didn’t change relatively, and the sea cucumber community in east Surabaya coastal composed of seven species, namely Phyllophorus dobsoni, Paracaudina australis, Cholochirus quadrangularis, Holothuria sanctori, Holothuria sp., H. forskali, and H. turriscelsa. Phyllophorus dobsoni was the most abundant species and could be found almost at all sampling sites while sandy substrate was the preferred habitat.Keywords: sea cucumber, distribution, habitat preference, east Surabaya coastal
Investigasi Power of the Tests terkait Non-Sample Prior Information Pada Hipotesis Satu Arah Pratikno, Budi
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

This research discussed investigating power of the tests that related to non-sample prior information (NSPI)on a simple linear regression for known variance on one-side hypothesis. Here, the power of the unrestricted test(UT), restricted test (RT), and preliminary-test test (PTT) are used. The method for investigating the best tests is amaximum power and minimum size. A simulation study and graphical analysis are given to make comparison of powerof the tests. The result showed that the power of the tests (UT, RT, PTT) are not really different for both types ofhypotheses (one-side maximum and minimum). The power of the PTT still lies between the power of the UT and RT(at any case), so it will be a best choice between thems.
Pengaruh Penambahan Ekstrak Alga Eucheuma cotonii terhadap Keberhasilan Mikropropagasi Tebu (Saccharum officinarum. L) Varietas VMC 86-550 Linggasari, Caecilia Noviati
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

Penelitian ini bertujuan mengetahui pengaruh variasi penambahan konsentrasi ekstrak Eucheuma cotonii sebagai suplemen dan substitusi media MS dengan eksplan tunas apikal tebu (Saccharum officinarum L. var VMC 86-550) secara in vitro melalui organogenesis langsung. Perlakuan dengan cara menambahkan ekstrak Eucheuma cotonii konsentrasi 0, 20, 40, 60, 80 dan 100 mg/L pada media MS dan media tanpa MS. Hasil penambahan Eucheuma cotonii tidak berpengaruh terhadap parameter panjang tunas dan jumlah tunas. Hasil pengujian AAS pada ekstrak Eucheuma cotonii sebagai suplemen media MS tidak dapat memacu pertumbuhan. Untuk unsur N dan P konsentrasinya melebihi batas zona toleransi sedangkan K, Ca dan Mg masih pada zona kahat.Kata kunci : Eucheuma cotonii, mikropropagasi, tebu, tunas apikal, AAS
Hybrid Algoritma Genetik dan Hill Climbing untuk Permasalahan Pengepakan Segi Empat Dua Dimensi I., Herlia Istiqomah
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

Rectangular packing problem described as n item that will be packed to a single object (which is bigger) to get the pack order of items into an object so that will minimize used object height. Hybrid of genetic algorithm and hill climbing is an algorithm that combines the process of genetic algorithm with hill climbing. Generally, the process of genetic algorithm is generate the first population, evaluation of chromosome, selection, crossover, and mutation. In this thesis, selection process used is roulette wheel, crossover process used is order based crossover, and hill climbing process used as replacement of mutation process. There’s 3 kinds of data being used and solve with Java programming language using Netbeans IDE 7.2 software. Using hybrid of genetic algorithm and hill climbing with Java programming language, achieved minimum height from used object is 17 for data with 10 items and object width 20. Second data with 49 items and object width 60, the minimum height achieved is 64. And the last with 97 items and object width 80, the minimum height achieved is 130.Keywords: Two Dimensional Rectangular Packing Problem, Genetic Algorithm, Hill Climbing, and Hybrid.
Pengaruh Konfigurasi Habitat Lahan Basah Terhadap Kelimpahan Burung Air Wilayah Mangrove Cemtre Dan Sekitarnya di Kecamatan Jenu, Kabupaten Tuban Subiyanto, Subiyanto
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

The influence of the environment and the presence of waterbird is analyzed in individual abundance of watebird in the wetland which consists of estuaries, mangroves, beaches, ponds, and rivers around the Mangrove Centre, District of Jenu Tuban. The study can provide information about the habitat elements which is considered as components of wetland habitat configurations which has a capacity of prediction of the emergence of water birds. Habitat configuration which includes elements of the habitat that consists of land area, extensive vegetation cover and salinity, is the independent variable that is expected to predict the emergence of water bird. Data collection was carried out directly in the observation stations and implemented in the laboratory. Samples of data were obtained from seven observation stations in the wetland complex that includes the estuary area, mangrove, beach-1, beach-2, pond-1, pond-2, and rivers. For wide area and vegetation cover were observed directly (in situ) while the salinity was analyzed in the laboratory (ex situ). Pearson Product Momment Correlation used for simple correlation analysis on the variables, and Standard Multiple Regression is used to examine the characteristics of the wetland habitat as the independent variable and the abundance of individuals of each species as the dependent variable, for each period in the rainy season and dry season. The results suggest a link between the configuration of wetland habitat with an abundance of water birds, especially extensive vegetation cover greatly affect the abundance of water birds. So it is recommended to conduct a conservation in a number of wetland, with extensive attention to the addition of vegetation around the open water in the wetland complex in order to maintain the abundance of species of water birds.Keywords: wetlands, habitat configuration, abundance, waterbirds, conservation.
Aktivitas Selulolitik dan Xilanolitik Enzim Sampah untuk Biobleaching Pelepah Batang Pisang Solikhatiningsih, Solikhatiningsih
Jurnal Matematika dan Ilmu Pengetahuan Alam Vol 17, No 1 (2015)
Publisher : Universitas Airlangga

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Abstract

This research aims to study the cellulolytic and xylanolytic activity of garbage enzyme. The garbage enzyme was prepared by fermentation of garbage parts of fruits, and vegetables, brown sugar and water in a weight ratio of 3: 1: 10 (w/w) for 3 months. Cellulolytic and xylanolytic activities were assayed toward CMC and xylan as substrates respectively. The reducing sugar was determined using DNS method. The garbage enzyme showed cellulose activity of 3.83 U/ml and xylanase activity of 5.66 U/ml. The biobleaching was initiated by boiling the dried stem of banana bunch in buffer pH 8 for 3 hours. The biobleaching process was performed at various concentration of garbage enzyme: 0, 5, 10, 15, 20, 25, 30, 35 and 40 % (W/V). The mixture of enzymatic reaction was incubated at 40 oC for 2 hours. The pulps were characterized of the water, cellulose, hemicellulose and lignin contents, whiteness, tensile index, tear index and its morphology. The result of this study showed that the addition of 20% garbage enzyme in biobleaching of stems of the banana bunch improved the pulp whiteness of 4.87%. Characteristics of pulps obtained were in accordance with ISO standards SNI-14-0091-1998 as raw material for paper pulp.Keywords: garbage enzyme, cellulase, xylanase, biobleaching, stems of the banana bunch

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