Eksakta : Berkala Ilmiah Bidang MIPA
Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) is an open access journal and peer-reviewed that publishes either original article or reviews. The journal is dedicated towards dissemination of knowledge related to the advancement in scientific research. The prestigious interdisciplinary editorial board reflects the diversity of subjects covered in this journal. Under the realm of science and technology, the coverage includes environmental science, pure and applied mathematics, agricultural research and engineering, biology, biotechnology, bioinformatics, Healthcare sciences (including clinical medicine, preventive medicine & public health), physics, biophysics, computer science, chemistry and bioengineering, to name a few. This Journal Is Published at 3 Month intervals on January-Marc, April-June, July-September and October-December
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310 Documents
<![CDATA[Comparison of Corrosion Rate in the Environment of 10% Acetic Acid solution with different Deflection. ]]>
<![CDATA[Nendi Suhendi Syafei]]>;
<![CDATA[S S Rizki]]>;
<![CDATA[Suryaningsih Suryaningsih]]>;
<![CDATA[Darmawan Hidayat]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/190
<![CDATA[The oil and gas industry exploration that will generally be followed by corrosive substances including sweet gas (eg H2S and CO2), it will result in corrosion event. The corrosion stress cracking will cause the carbon steel pipe to break so that production oil and gas can be stopped. The research aims in this paper is to analyze the corrosion event of carbon steel pipe in laboratory scale on acid environment with the existence of sweet gas H2O and CO2 by using three points loading method. This research uses carbon steel pipe API 5L-X65 which stay in condensation environment of 1350 ml aquades, 150 ml acetic acid. Based on the figure (5.a) and figure (5.b) that the corrosion rate will increase with increasing exposure time, and the greater the stress that is given, the corrosion rate increases according to the image (6.a) and image (6.b). Whereas based on the results of microstructural tests using optical microscopes, pitting corrosion occurs, and corrosion events occur are the stress corrosion cracking transgranular and intergranular based on figure 8.]]>
<![CDATA[A Preliminary Screening of the Different of Secondary Metabolites Ruku-Ruku Leaves (Ocimum tenuiflorum Linnen) in West Sumatera ]]>
<![CDATA[Hesty Parbuntari]]>;
<![CDATA[Sri Benti Etika]]>;
<![CDATA[Melindra Mulia]]>;
<![CDATA[Elfanny Delvia]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/193
<![CDATA[Ruku-ruku leaves are used to remove distinctive odors from fish in some cuisine of West Sumatra. The characteristic odor comes from secondary metabolites especially essential oils. Therefore, secondary metabolites in ruku-ruku leaves have the potential to be further investigated as a source of bioactive compounds. The phytochemical screening of ruku-ruku leaves is a preminilary qualitative test that needs to be done to maximise its function as a medicinal plant. Based on the result data, there are some different result of flavonoid, steroids, and triterpenoids identification. Ruku-ruku leaves from Pesisir Selatan and Padang Panjang shows less flavonoid compounds tham Payakumbuh, Batusangkar, and Lubuk Alung. Both of this city and Payakumbuh also gives less steroids and triterpenoids. The factor influencing this result is caused by several factors, namely temperature, humidity, light exposure, and salinity.]]>
<![CDATA[Statistical Analysis to Evaluate The Service Quality at Community Health Center in Padang, Indonesia ]]>
<![CDATA[Aidinil Zetra]]>;
<![CDATA[Ferra Yanuar]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/198
<![CDATA[Healthcare provider have to take care of patient satisfaction. Therefore, the management should do a kind of evaluation to examine the patient satisfaction on the corresponding services. The purpose of this study is to evaluate the service quality of public health centre and to identify the attributes of services to be improved. This study was cross sectional study conducted by distributing the questionairres to the patients of public health centre in Padang, Indonesia from April to June 2015. This study involved 446 respondents with complete information. Customer Satisfaction Index (CSI) was used to measure the service quality of corresponding public health centre. Importance Performance Analysis (IPA) approach was also applied to identify any attributes to be improved. The respondents of this study were very satisfied with the health service that they ever got. All attributes of service were plotted in four quadrants. This study proved that CSI and IPA methods are pertinent to be applied to measure patient satisfaction and identify any attributes of service to be maintained or improved.]]>
<![CDATA[Parameter Estimation STAR (1;1) Model Using Binary Weight ]]>
<![CDATA[Khafsah Joebaedi]]>;
<![CDATA[Iin Irianingsih]]>;
<![CDATA[Badrulfalah Badrulfalah]]>;
<![CDATA[Dwi Susanti]]>;
<![CDATA[Kankan Parmikanti]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/199
<![CDATA[Space Time Auto Regressive(1;1) Model or STAR(1;1) model is a form of model that involves location and time. The STAR(1;1) model is a stationary space time model in mean and variance. The STAR model can be used to forecast future observations at these locations by involving the effects of observations at other nearby locations in spatial lag 1 and lag time 1 [2]. The STAR model can be written as a linear model assuming that error is normally distributed with zero mean and constant variance. In this research, the parameter estimation procedure for STAR model using binary weight, MKT method and STAR model for the estimation of petroleum production in 3 wells is assumed to be in a homogeneous reservoir.]]>
<![CDATA[Leaf Anatomical Modification in Drought of Rice Varieties (Oryza sativa L.) ]]>
<![CDATA[Anggara Dwi Putra Zagoto]]>;
<![CDATA[Violita Violita]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/201
<![CDATA[Each organ plant has been formed perfectly to support physiological processes in an unfavorable environmental condition. Rice (Oryza sativa L.) be included plants sensitive to drought conditions during a stage of growth and development. This will cause pressure (stress) resulting in a decrease in rate metabolism in leaf cells. Leaf anatomical characteristics are criteria that can be used to identify plants that are tolerant to drought. Anatomical response leaves in drought conditions inform the development of leaf photosynthetic parts carrying out changes in anatomical structure morphology includes changes in cell walls, organ size, changes in direction growth, including dropping leaves and enhancing the life cycle. The research aimed to determine the anatomic response leaves rice varieties (Oryza sativa L.) to drought stress. Five rice varieties used were given drought-stress treatment for 12 days. Identification leaf anatomical structures using microscopic slices of transverse was made according to the paraffin method. Changes in the anatomical structure of leaves of drought-stress have decreased bulliform cells increase in size, the thickness epidermis cells in an effort to retain the water content in cells, and reducing the size and total stomata with purpose process control flow of transpiration and water use efficiency.]]>
<![CDATA[Broiler Response on Increase in Flour Leaves Miana (Coleus atropurpureus, L) as a Feed Aditive in Ration ]]>
<![CDATA[Nelzi Fati]]>;
<![CDATA[Ramond Siregar]]>;
<![CDATA[Ulva Mohtar Luthfi]]>;
<![CDATA[Debby Syukriani]]>;
<![CDATA[Toni Malvin]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/203
<![CDATA[Increased bacterial resistance to antibiotics provides a great opportunity to obtain antibacterial compounds by utilizing bioactive compounds from biological natural wealth. In Indonesia there are many known medicinal plants. Miana plants (Coleus atropurpureus, L) are one of the potential medicinal plants in Indonesia. This plant is widely used as medicine. This study aims to determine the effect of adding miana leaf flour to the ration on body weight gain, feed consumption, feed conversion and carcass percentage. This study used a completely randomized design with 5 treatments and 4 replications. The treatment was A = control, B = 1% Miana leaf flour / kg ration. C = 2% leaf flour miana / kg ration, D = 3% miana leaf flour / kg ration E = 4% miana leaf flour / kg ration. What was observed were performance and carcass including feed consumption, feed conversion, body weight gain, carcass percentage. The results of this study showed that the addition of miana leaf flour in the ration had no significant effect (P> 0.05) on body weight gain, feed conversion, feed consumption and carcass percentage. Giving miana leaf flour in the ration can be tolerated up to 4% in broiler rations.]]>
<![CDATA[Development of a Digital Dip Coating System Based Microcontroller ]]>
<![CDATA[Yohandri Yohandri]]>;
<![CDATA[Khairunnisa Khairunnisa]]>;
<![CDATA[Ramli Ramli]]>;
<![CDATA[Rahadian Zainul]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/204
<![CDATA[Coating techniques are important parts in the development of nano material technology. In this paper, the development of coating technology based on microcontroller using dip coating is presented. Arduino microcontroller is implemented to control the immersion time and the speed of withdrawal of material out of the coating fluid through a stepper motor. In addition, the withdrawal speed can be digitally entered through a keypad with a value range of 0.02 mm/s to 10 mm/s. The experiment results showed the percentage of accuracy and precision of the microcontroller based dip coater was very high. Based on these results, the developed dip coater is satisfied to be used in the development of nanotech materials]]>
<![CDATA[Bacterial Isolation Which is Potential as Cellulosa Pedegradation in Coastal Performance In Tanjungpinang City ]]>
<![CDATA[Iwan Iskandar]]>;
<![CDATA[Hevi Horiza]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 20 No. 2 (2019): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol20-iss2/206
<![CDATA[Many black water or feces and urine field observations in Tanjung Pinang City were dumped directly into the ditches, rivers, and sea. This proves that the management of domestic liquid waste in the City of Tanjungpinang, especially black water, has not yet received serious attention, resulting in a decline in environmental quality. One of the stages in processing black water is decomposition. The decomposition process can be assisted by bacteria, one of which is cellulose-degrading bacteria. This study aims to find bacterial isolates that have the potential to degrade cellulose in feces from coastal soils in Tanjung Pinang City. This research is a laboratory experimental research. The results of this study were obtained 16 bacterial isolates that can degrade cellulose. From these 16 isolates, 3 genera of bacteria were obtained, namely Pseudomonas, Acetobacter and Acinetobacter. Keywords: Cellulose Degradation Bacteria, Coastal Soil]]>
<![CDATA[The Effect of Ethanol Solvent Concentration on Antimicrobial Activities The Extract of Andalas Endophytic Bacteria (Morus Macroura Miq.) Fermentation Product ]]>
<![CDATA[Larasati Arum Utami]]>;
<![CDATA[Dwi Hilda Putri]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 21 No. 1 (2020): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol21-iss1/210
<![CDATA[Anti-Biotic resistance is a health problem globally. It is able to overcome with a new anti-microbial compound that can be produced from Andalas endophytic bacteria. This compound can be obtained through the fermentation process. In order to separate this active-compound, it is needed to use the extraction method. In this method, the solvent is functioned as the extractor. One of the solvent which is commonly used is ethanol. This research is aimed to know the effect of ethanol concentration toward antibacterial activity from extracted bacterial fermentation products of Andalas endophytic bacteria isolate JDT 1B. The fermented products are extracted by using the maceration method. The concentrations are 100%, 80%, 70%. A test of anti-microbial activity is used disk diffusion method. The extracted concentrations tested for each solvent are 50%, 25%, 12,5%, and 6.25%. Anti-bacterial activity is analyzed by using factorial design. The factorial result showed there is no significant contrast between ethanol concentration mentioned toward anti-bacterial activity from extracted bacterial fermentation products of Andalas endophytic bacteria Isolate JDT 1B. The concentration of extracted fermentation product using 70% ethanol has the same inhibition zone as control is 6,25%.]]>
<![CDATA[Convergence Analysis from the Solution of Riccati’s Fractional Differential Equation by Using Polynomial Least Squares Method ]]>
<![CDATA[Dian Nuryani]]>;
<![CDATA[Endang Rusyaman]]>;
<![CDATA[Betty Subartini]]>
<![CDATA[ EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 21 No. 1 (2020): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464) ]]>
Publisher : <![CDATA[Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia ]]>
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DOI: 10.24036/eksakta/vol21-iss1/211
<![CDATA[Riccati's Fractional Differential Equation (RFDE) has become a topic of study for researchers because RFDE can model variety of phenomenon in science such as random processes, optimal control and diffusion problems. Phenomena that can be modeled in a mathematical form can make it easier for humans to analyze several things from that phenomenon. RFDE generally does not have an exact solution, therefore a numerical approach solution is needed, one of the methods that gives good accuracy to the actual or exact solution is Polynomial Least Squares, where the errors calculated based on mean absolute percentage error (MAPE) produce a percentage below 1%. In addition, the convergence of a sequence from approximate solutions indicates that the sequence will converge to a solution.]]>
