The Universitas Mulawarman is a public university located in Samarinda, East Kalimantan, Indonesia. It was established on September 27, 1962, making it the oldest tertiary education institution in East Kalimantan. With more than 35,000 students, Universitas Mulawarman is the university with the most students in Kalimantan. Its main campus is in Gunung Kelua, while other campuses are in Pahlawan Road, Banggeris Street and Flores Street of Samarinda.Universitas Mulawarman is striving to be the world-class university which is able to play a role in development through education, research and community service which relies on natural resources, especially the tropical rainforest and its environment. Wikipedia.
Nurhadi M.,Mulawarman University
AIP Conference Proceedings | Year: 2017
Titania supported sulfonated coal was created as heterogeneous catalyst for epoxidation of 1-octene with aqueous hydrogen peroxide as oxidant at room temperature. The catalysts were prepared from coal that was sulfonated with H2SO4 (97%) and impregnated 7.2%wt with titanium(IV) isopropoxide (Ti(PrO)4). All catalysts coal (C), CS, Ti(7.2)-CS and Ti(7.2)-CSC were characterized by FTIR. The catalytic performance was tested for epoxidation of 1-octene with H2O2 aqueous as oxidant. It is found that Ti(7.2)-CS possessed the best catalytic performance and it gave the highest 1,2 epoxyoctene 322 μmol. © 2017 Author(s).
Nurhadi M.,Mulawarman University
Key Engineering Materials | Year: 2017
One of the coal combustion ashes is coal bottom ash. Low rank coal bottom ash can act as TiO2 catalyst's support which was calcined at varying temperature, has been created. The low rank coal bottom ash model was collected from low rank coal which burned in muffle furnace at 800 °C for 2 h. Subsequently, the low rank coal bottom ash was impregnated with titanium(IV) isopropoxide (Ti(PrO)4) 500 μmol, and then calcined at variation temperature of 300, 400, 500, 600 and 700 °C. The modified physiochemical property of catalysts were determined UV-vis spectroscopy, N2 adsorption-desorption and hydrophobicity test. The performances of the catalysts were tested for styrene oxidation with H2O2 aqueous as oxidant. It is found that the low rank coal bottom ash was as good catalyst support, whereby TiO2 supported low rank coal bottom ash which calcined at 400 °C possessed the best catalytic activity with styrene conversion 45% and selectivity 87%. © 2017 Trans Tech Publications, Switzerland.
Nurhadi M.,Mulawarman University
Bulletin of Chemical Reaction Engineering and Catalysis | Year: 2017
The modified coal char from low-rank coal by sulfonation, titanium impregnation and followed by alkyl silylation possesses high catalytic activity in styrene oxidation. The surface of coal char was undergone several steps as such: modification using concentrated sulfuric acid in the sulfonation process, impregnation of 500 mmol titanium(IV) isopropoxide and followed by alkyl silylation of n-octadecyltriclorosilane (OTS). The catalysts were characterized by X-ray diffraction (XRD), IR spectroscopy, nitrogen adsorption, and hydrophobicity. The catalytic activity of the catalysts has been examined in the liquid phase styrene oxidation by using aqueous hydrogen peroxide as oxidant. The catalytic study showed the alkyl silylation could enhance the catalytic activity of Ti-SO3H/CC-600(2.0). High catalytic activity and reusability of the o-Ti-SO3H/CC-600(2.0) were related to the modification of local environment of titanium active sites and the enhancement the hydrophobicity of catalyst particle by alkyl silylation. Copyright © 2017 BCREC GROUP. All rights reserved.
Muslim T.,Mulawarman University
Biodiversitas | Year: 2017
Herpetofauna community is established because of habitat suitability or adaptation process that forces a species to survive. In the mining region, herpetofauna habitat change has occurred. The loss of natural habitat and the creation of an artificial habitat result in severance of corridor as a connecting line between herpetofauna habitats so that only microhabitat remains. Microhabitats of herpetofauna survive on limited food resources. The process of surviving of herpetofauna in microhabitats is reflected on the phenomenon of the food chain i.e. reptiles act as predators (top) and amphibians are as preys and as insect predators (middle). In the mining area, an area with a source of water is the destination for all animals, especially herpetofauna, and it even becomes the microhabitat for certain species. The purpose of this study is to determine the species of herpetofauna, its communities and its domination on the water area its microhabitats within the mine area. The exploration is carried out by direct observation (visual encounter surveys). The survey location determination is done intentionally (purposive sampling) on the potential habitat in some locations of water sources, such as pit dam, settling pond, man-made lake (embung), rivers and swamps. Based on the similarity index, there are five species of herpetofauna dominating the life in microhabitats and playing role in the formation of food chain community. Enhydris enhydris and Dendrelaphis pictus are species of snake and act as predator of frog Fejervarya cancrivora and Polypedates leucomystax. © 2017, Society for Indonesian Biodiversity. All rights reserved.
AIP Conference Proceedings | Year: 2016
Poisson regression has been used if the response variable is count data that based on the Poisson distribution. The Poisson distribution assumed equal dispersion. In fact, a situation where count data are over dispersion or under dispersion so that Poisson regression inappropriate because it may underestimate the standard errors and overstate the significance of the regression parameters, and consequently, giving misleading inference about the regression parameters. This paper suggests the generalized Poisson regression model to handling over dispersion and under dispersion on the Poisson regression model. The Poisson regression model and generalized Poisson regression model will be applied the number of filariasis cases in East Java. Based regression Poisson model the factors influence of filariasis are the percentage of families who don't behave clean and healthy living and the percentage of families who don't have a healthy house. The Poisson regression model occurs over dispersion so that we using generalized Poisson regression. The best generalized Poisson regression model showing the factor influence of filariasis is percentage of families who don't have healthy house. Interpretation of result the model is each additional 1 percentage of families who don't have healthy house will add 1 people filariasis patient. © 2016 AIP Publishing LLC.
Rijai L.,Mulawarman University
Journal of Pharmaceutical Sciences and Research | Year: 2017
Saponins have specific characteristics are highly polar, generally, as a compound isomers, diversity of this compounds founded with a large number in living natural material, complex chemical structure and physicochemical properties of the compound is very similar to one another. Characteristics such as a major cause difficulty separation of the compound and the difficulty in determining the molecular structure by conventional techniques. Triterpene saponins for the separation more difficult because more polar, as well as the elucidation of the structure because the structure is more complex. isolation Technique of saponins most rapidly and precisely locate compound saponin saponin extraction using methanol-water (7: 3 or 1: 1), the purification of saponin mixture with the addition of ether solvent in a solution containing saponin fractions, isolation techniques by preparative HPLC or semi- preparative reversed-phase HPLC eluent with the determination of the analytical column; and for the determination of the structure quickly and accurately using1H and13C NMR-2D frequency ≥ 400 MHz techniques DEPT, HH-COSY, HMBC, HMQC / HSQC, ROESY-2D, ROE-1D, TOCSY-1D, and spectrometry FTIR and FABMS like ESIMS. © 2017, Pharmainfo Publications. All rights reserved.
Hadibarata T.,Ehime University |
Hadibarata T.,Mulawarman University |
Tachibana S.,Ehime University
Journal of Environmental Sciences | Year: 2010
Polyporus sp. S133, a fungus collected from contaminated soil, was used to degrade phenanthrene, a polycyclic aromatic hydrocarbon, in a mineral salt broth liquid culture. A maximal degradation rate (92%) was obtained when Polyporus sp. S133 was cultured for 30 days with agitation at 120 r/min, as compared to 44% degradation in non-agitated cultures. Furthermore, the degradation was affected by the addition of surfactants. Tween 80 was the most suitable surfactant for the degradation of phenanthrene by Polyporus sp. S133. The degradation rate increased as the amount of Tween 80 added increased. The rate in agitated cultures was about 2 times that in non-agitated cultures. The mechanism of degradation was determined through the identification of metabolites; 9,10-phenanthrenequinone, 2,2′-diphenic acid, phthalic acid, and protocatechuic acid. Several enzymes (manganese peroxidase, lignin peroxidase, laccase, 1,2-dioxygenase and 2,3-dioxygenase) produced by Polyporus sp. S133 were detected during the incubation. The highest level of activity was shown by 1,2-dioxygenase (187.4 U/L) after 20 days of culture. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.
Raffles Bulletin of Zoology | Year: 2016
Little is known about the ecology of the rare marbled cat Pardofelis marmorata on Borneo. In addition, the little information that is available on the species often comes from incidental sightings. Here we use the MaxEnt algorithm to produce a habitat suitability map for this species based on a compilation of existing data. We collected 105 marbled cat occurrence records for Borneo, of which 27 (Balanced Model) or 69 (Spatial Filtering Model) were used to estimate potential habitat suitability. The resulting relative habitat suitability map showed key conservation areas in Borneo. According to these results it appears that the most suitable habitats for marbled cat are lowland forests, but these forests are most threatened by deforestation and other anthropogenic activities. It is imperative to develop appropriate conservation strategies for the marbled cat on Borneo, including long-term research and monitoring, reduction of human disturbances in lowland forests, increased data-sharing and research networking, and stakeholder involvement for conservation planning and activities. © 2016 National University of Singapore.
Hindryawati N.,Universiti Malaysia Pahang |
Hindryawati N.,Mulawarman University |
Maniam G.P.,Universiti Malaysia Pahang
Ultrasonics Sonochemistry | Year: 2015
This study demonstrates the potential of Na-silica waste sponge as a source of low cost catalyst in the transesterification of waste cooking oil aided by ultrasound. In this work an environmentally friendly and efficient transesterification process using Na-loaded SiO2 from waste sponge skeletons as a solid catalyst is presented. The results showed that the methyl esters content of 98.4 ± 0.4 wt.% was obtainable in less than an hour (h) of reaction time at 55 °C. Optimization of reaction parameters revealed that MeOH:oil, 9:1; catalyst, 3 wt.% and reaction duration of 30 min as optimum reaction conditions. The catalyst is able to tolerant free fatty acid and moisture content up to 6% and 8%, respectively. In addition, the catalyst can be reused for seven cycles while maintaining the methyl esters content at 86.3%. Ultrasound undoubtedly assisted in achieving this remarkable result in less than 1 h reaction time. For the kinetics study at 50-60 °C, a pseudo first order model was proposed, and the activation energy of the reaction is determined as 33.45 kJ/mol using Arrhenius equation. © 2014 Elsevier B.V. All rights reserved.
Biodiversitas | Year: 2016
Erwin. 2016. Microscopic decay pattern of yellow meranti (Shorea gibbosa) wood caused by white-rot fungus Phlebia brevispora. Biodiversitas 17: 417-421. The anatomical changes of wood decaying caused by white-rot fungus Phlebia brevispora could provide the basis for evaluating and analysis of decay on yellow meranti (Shorea gibbosa) heartwood. By using soil-block test procedure of JIS K-1571 and microscopic analysis, a progressive decay in vitro of S. gibbosa wood caused by P. brevispora was well characterized. The percentage of wood weight loss was ranged from 0.91% to 12.34%in 2-12 weeks' incubation. On the first 6 weeks of incubation of S. gibbosa infected with P. brevispora, the early stages decay, in which pit erosion and slight erosion of cell walls facilitated by hyphal spreading among cells. The intermediate decay features of numerous and conspicuous holes as well as erosion troughs in cell walls were found after 8 weeks' incubation. Furthermore, complete degradation of wood cell components, defined as the advanced stage of decay, was found in some areas of wood after 12 weeks' incubation. The pattern of wood decay was similar to those of the decayed xylem of S. gibbosa stem canker in field conditions. © 2016, Society for Indonesian Biodiversity. All right reserved.