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AGRICULTURE (680 journals)            First | 1 2 3 4     

Showing 601 - 263 of 263 Journals sorted alphabetically
Science and Technology Indonesia     Open Access  
Science as Culture     Hybrid Journal   (Followers: 10)
Science, Technology and Arts Research Journal     Open Access   (Followers: 1)
Scientia Agricola     Open Access  
Scientia Agropecuaria     Open Access  
Seed Science and Technology     Full-text available via subscription  
Seed Science Research     Hybrid Journal  
Selçuk Tarım ve Gıda Bilimleri Dergisi     Open Access  
Semiárida     Open Access  
Siembra     Open Access  
Small Ruminant Research     Hybrid Journal   (Followers: 2)
Smart Agricultural Technology     Open Access  
Social & Cultural Geography     Hybrid Journal   (Followers: 26)
Social and Natural Sciences Journal     Open Access  
South African Journal of Agricultural Extension     Open Access   (Followers: 3)
South African Journal of Economics : SAJE     Hybrid Journal   (Followers: 7)
South African Journal of Plant and Soil     Hybrid Journal   (Followers: 1)
Spatial Economic Analysis     Hybrid Journal   (Followers: 9)
Sri Lanka Journal of Food and Agriculture     Open Access   (Followers: 1)
Stiinta Agricola     Open Access  
Studies in Australian Garden History     Full-text available via subscription   (Followers: 4)
Sugar Tech     Hybrid Journal   (Followers: 1)
Sustainability Agri Food and Environmental Research     Open Access   (Followers: 4)
Sustainability and Climate Change     Full-text available via subscription   (Followers: 18)
Sustainable Agriculture Research     Open Access   (Followers: 3)
Sustainable Environment Agricultural Science (SEAS)     Open Access  
Tanzania Journal of Agricultural Sciences     Open Access   (Followers: 4)
Terra Latinoamericana     Open Access  
The Agriculturists     Open Access  
The Journal of Research, PJTSAU     Open Access   (Followers: 13)
Translational Animal Science     Open Access  
Trends in Agricultural Economics     Open Access   (Followers: 7)
Tropical Agricultural Research     Open Access   (Followers: 2)
Tropical Agricultural Research and Extension     Open Access   (Followers: 2)
Tropical and Subtropical Agroecosystems     Open Access  
Tropical Grasslands - Forrajes Tropicales     Open Access  
Tropical Technology Journal     Open Access  
Tropicultura     Open Access  
Turkish Journal of Agricultural and Natural Science / Türk Tarım ve Doğa Bilimleri Dergisi     Open Access  
Turkish Journal of Agricultural Engineering Research     Open Access  
Ukrainian Journal of Veterinary and Agricultural Sciences     Open Access  
Uluslararası Tarım ve Yaban Hayatı Bilimleri Dergisi / International Journal of Agricultural and Wildlife Sciences     Open Access  
UNICIÊNCIAS     Open Access  
Universal Journal of Agricultural Research     Open Access  
Universidad y Ciencia     Open Access  
Urban Agricultural & Regional Food Systems     Open Access  
Viticulture Data Journal     Open Access  
VITIS : Journal of Grapevine Research     Open Access   (Followers: 1)
Walailak Journal of Science and Technology     Open Access  
Wartazoa. Indonesian Bulletin of Animal and Veterinary Sciences     Open Access  
Weed Biology and Management     Hybrid Journal   (Followers: 4)
Weed Research     Hybrid Journal   (Followers: 5)
West African Journal of Applied Ecology     Open Access  
Wildlife Australia     Full-text available via subscription   (Followers: 1)
Wirtschaftsdienst     Hybrid Journal   (Followers: 5)
World Journal of Agricultural Research     Open Access  
World Mycotoxin Journal     Hybrid Journal   (Followers: 3)
World's Poultry Science Journal     Full-text available via subscription   (Followers: 3)
علوم آب و خاک     Open Access  

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Science and Technology Indonesia
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2580-4405 - ISSN (Online) 2580-4391
Published by Sriwijaya University Homepage  [4 journals]
  • Synthesis of Cellulose–Polylactic Acid Microcapsule as a Delivery
           Agent of Rifampicin

    • Authors: Suripto Dwi Yuwono, Ridho Nahrowi, Andi Setiawan, Ni Luh Gede Ratna Juliasih, Irza Sukmana, Wasinton Simanjuntak, Sutopo Hadi
      Pages: 263 - 268
      Abstract: In medicinal field, delivery agent is a very important substance to improve the efficiency of drug used by improving the stability and preventing the degradation of drug during the medical treatment. Due to these important roles of the drug delivery agent, the search of effective agent is continuously in progress. In this respect, this current research was carried out to synthesize cellulose–polylactic acid (cellulose-PLA), as a potential delivery agent of rifampicin for the curing of tuberculosis. Cellulose was isolated from cassava bagasse, while PLA was obtained from commercial supplier. The two raw materials were used to synthesize cellulose–PLA in 3.5% HCl as solvent under magnetic stirring. The product obtained was then characterized by Fourier-Transform Infrared spectroscopy (FTIR), Particle-Size Analysis (PSA), and Scanning Electron Microscopy (SEM). The FT-IR result showed the presence of hydroxy (3446 to 3429 cm−1) and carbonyl (1757 to 1759 cm−1), confirming the formation new bond between cellulose and PLA. The PSA characterization displays a particle-sizes of PLA are in the range of 960–92780 nm, while cellulose–PLA are in the range of 100–17730 nm demonstrating that cellulose-PLA combined to form more compact structures. The results of SEM analysis indicate the distinct feature of cellulose-PLA, and combination of the features in the cellulose and PLA image. The results of the dissolution test carried out two different concentrations of rifampicin revealed that the optimum dissolution (8.42%) was achieved with cellulose–PLA of 0.3%, dissolution time of 12 h, and pH of 7.4.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.263-268
      Issue No: Vol. 7, No. 3 (2022)
       
  • Pattern Recognition using Multiclass Support Vector Machine Method with
           Local Binary Pattern as Feature Extraction

    • Authors: Nursyiva Irsalinda, Sugiyarto Surono, Indah Dwi Ratna Sary
      Pages: 269 - 274
      Abstract: Corn is an essential agricultural commodity since it is used in animal feed, biofuel, industrial processing, and the manufacture of non-food industrial commodities such as starch, acid, and alcohol. Early detection of diseases and pests of corn aims to reduce the possibility of crop failure and maintain the quality and quantity of crop yields. A decision tree is a nonparametric classification model in statistical machine learning that predicts target variables using tree-structured decisions. The performance of this model can increase significantly if the continuous predictor variables are discretized into valid categories. However, in some cases, the result does not provide satisfactory performance. The possible cause is the ambiguity in discretizing predictor variables. The incorporation of fuzzy membership functions into the model to resolve discretization ambiguity issues. This work aims to classify diseases and pests of corn plants using the decision tree model and improve the model’s performance by implementing fuzzy membership functions. The main contribution of this work is that we have shown a significant improvement in the decision tree model performance by implementing fuzzy membership functions; S-growth, triangle, and S-shrinkage curves. The proposed fuzzy model is better than the decision tree model, with an average performance increase from the largest to the smallest; kappa (12.16%), recall (11.8%), F-score (9.71%), precision (5.08%), accuracy (3.23%), specificity (1.94%), and AUC (0.49%). The combination of bias and variance generated by the proposed model is quite small, indicating that the model is able to capture data trends well.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.269-274
      Issue No: Vol. 7, No. 3 (2022)
       
  • Modification of Mg/Al-LDH Intercalated Metal Oxide (Mg/Al-Ni) to Improve
           The Performance of Methyl Orange and Methyl Red Dyes Adsorption Process

    • Authors: Nova Yuliasari, Arini Fousty Badri, Alfan Wijaya, Patimah Mega Syah Bahar Nur Siregar, Amri, Mardiyanto, Risfidian Mohadi, Aldes Lesbani
      Pages: 275 - 283
      Abstract: Modification of Mg/Al-LDH intercalated metal oxide (Mg/Al-Ni) was successfully formed by the coprecipitation method at pH 10, which is indicated by the XRD diffraction, FTIR spectrum, and BET analysis. Mg/Al-LDH increased surface area after intercalated Ni from 8.621 m2/g to 9.821 m2/g and improved performance in process regeneration which can be used in the three cycles. Mg/Al-LDH after intercalated metal oxide (Ni) increases adsorption capacity of is 69.930 mg/g to 71.429 mg/g for methyl orange (MO) and 77.519 mg/g to 98.039 mg/g for methyl red (MR). Equilibrium time on the adsorption process occurred at 90 minutes with adsorption kinetics followed pseudo-second-order (PSO). Thermodynamic parameters indicate that the adsorption process is spontaneous and endothermic with the physical adsorption process.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.275-283
      Issue No: Vol. 7, No. 3 (2022)
       
  • Performance Improvement of Decision Tree Model using Fuzzy Membership
           Function for Classification of Corn Plant Diseases and Pests

    • Authors: Yulia Resti, Chandra Irsan, Muflika Amini, Irsyadi Yani, Rossi Passarella, Des Alwine Zayantii
      Pages: 284 - 290
      Abstract: Corn is an essential agricultural commodity since it is used in animal feed, biofuel, industrial processing, and the manufacture of non-food industrial commodities such as starch, acid, and alcohol. Early detection of diseases and pests of corn aims to reduce the possibility of crop failure and maintain the quality and quantity of crop yields. A decision tree is a nonparametric classification model in statistical machine learning that predicts target variables using tree-structured decisions. The performance of this model can increase significantly if the continuous predictor variables are discretized into valid categories. However, in some cases, the result does not provide satisfactory performance. The possible cause is the ambiguity in discretizing predictor variables. The incorporation of fuzzy membership functions into the model to resolve discretization ambiguity issues. This work aims to classify diseases and pests of corn plants using the decision tree model and improve the model’s performance by implementing fuzzy membership functions. The main contribution of this work is that we have shown a significant improvement in the decision tree model performance by implementing fuzzy membership functions; S-growth, triangle, and S-shrinkage curves. The proposed fuzzy model is better than the decision tree model, with an average performance increase from the largest to the smallest; kappa (12.16%), recall (11.8%), F-score (9.71%), precision (5.08%), accuracy (3.23%), specificity (1.94%), and AUC (0.49%). The combination of bias and variance generated by the proposed model is quite small, indicating that the model is able to capture data trends well.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.284-290
      Issue No: Vol. 7, No. 3 (2022)
       
  • Study of The Electrical, Optical and Morphological Properties in Submicron
           and Microstructured ZnO Thin Films Obtained by Spin Coating and Chemical
           Bath Deposition

    • Authors: C. López-Esmerio, C. Ruiz-Rojas, J. Angulo-Rocha, E. Lizárraga-Medina, Francisco Ramos-Brito, E. Camarillo-García, R. Martinez-Martinez, M. Aguilar-Frutis, M. García-Hipólito
      Pages: 291 - 302
      Abstract: In the present work the synthesis of ZnO semiconductor thin films was performed successively using spin coating and chemical bath deposition techniques. The deposition was made by varying the concentration of zinc acetate and hexamethylenetetramine (HMTA: ZnAc) in the precursor solution. This process led to two preferred growth directions (002) and (101), both with very similar texture coefficients, too; a noticeable change in morphology of structured surface, variation in unit cell parameters and crystalline grain size. All the films turned out homogeneously submicro and microstructured and with a wurtzite-type hexagonal crystalline structure. Using pre-loaded Mathematica 11.3 software functions and an algorithm developed in it, the micrographies were analyzed to calculate the percentage of substrate-covered area which was always greater than 80%. Likewise, it also found that resistivity decreases at a higher percentage of covered area and that the variation in the shape of the photo luminescent emission spectrum can be considered as a qualitative indication of the concentration of charge carriers.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.291-302
      Issue No: Vol. 7, No. 3 (2022)
       
  • Antioxidant and Antibacterial Activities of Endophytic Fungi Extracts of
           Syzygium zeylanicum

    • Authors: Syarifah, Elfita, Hary Widjajanti, Arum Setiawan, Alfia Rahma Kurniawati
      Pages: 303 - 312
      Abstract: Syzygium zeylanicum, one of the other therapeutic plants found in Indonesia, is used to treat various ailments, such as antimicrobial, anti-inflammatory, antioxidant, arthritis, antidiabetic, mosquitocidal, antitumor, and anti-rheumatic agents. The massive use of plant extracts has caused the development of isolation of bioactive compounds thru their endophytic. The present research aimed to obtain endophytic fungal isolates from the stem bark and leaves of Jambu nasi-nasi (S. zeylanicum) and analyze endophytic fungal extracts’ antioxidant and antibacterial activity. Endophyte identification was performed morphologically, and isolates with high biological activity were molecularly characterized. The antibacterial activity was evaluated by the disc diffusion method, and the antioxidant activity was evaluated by the DPPH method. In total, 10 endophytic fungi were isolated and identified as Phialemonium sp. (Code SZT3), Acremonium sp. (Code SZT4), Trichoderma aureoviridae (Code SZT5), Trichoderma koningi (Code SZT7), Phytium torulosum (Code SZL1), Phytium zingiberum (Code SZL2), Septonema sp. (Code SZL3), Lasiodiplodia pseudotheobromae (Code SZL4), Volutella cilliata (SZL5), and Trichophyton mentagrophytes (Code SZL7). Isolate SZL4 gave activity the highest antioxidant (IC50 = 3.30 ''''g/mL) and strong antibacterial activity against four pathogens bacterial (S. thypi, B. subtilis, S. aureus, and E. coli). The potential endophytic fungi based on molecular analysis was Lasiodiplodia pseudotheobromae with accession number OK668257. These endophytic fungi can be developed into new sources of antibacterial and antioxidant bioactive compounds through further studies.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.303-312
      Issue No: Vol. 7, No. 3 (2022)
       
  • Droplet Combustion and Thermogravimetric Analysis of Pure Coconut Oil,
           Clove Oil, and Their Mixture

    • Authors: Adhes Gamayel, MN Mohammed, Mohamad Zaenudin, Eddy Yusuf
      Pages: 313 - 319
      Abstract: The droplet combustion and thermal behavior of pure coconut oil (PCO), clove oil, and their mixture were experimentally investigated. The mixture fuels were PCO and clove oil at the percentage of 10% based on volume (PCO-CO10). The experimental method uses droplet combustion and thermogravimetric analysis. The fuel droplet was suspended in the junction of k-type thermocouple and ignited by a coil heater. The ignition and combustion processes of droplets were recorded using a digital single-lens reflex camera at 25 fps. Thermogravimetric analysis with alumina crucible was prepared to investigate the thermal behavior of fuel. The result showed that the sequence of ovoid flame for PCO and PCO-CO10 take place until 0.4 second and 0.44 second, respectively. Complete combustion was explained in that sequence. The ovoid flame was formed when eugenol, terpene, and lauric acid were evaporated first in both PCO and PCO-CO10. Minimum ovoid flame takes place in clove oil due to soot tendency in the burning process that marked flame as the open tip. PCO-CO10 has the highest peak temperature due to the presence both of double carbon chains in fatty acid and aromatic ring structures, which were easy to decompose in high energy input. Clove oil was the lowest onset temperature, which indicates more volatile matter in this fuel and PCO has the highest thermal stability due to the fatty acid component in their fuel.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.313-319
      Issue No: Vol. 7, No. 3 (2022)
       
  • Formulation and Evaluation of Solid Lipid Nanoparticles Loading
           Erythromycin Ethylsuccinate by Heating Emulsification and Homogenization
           Methods

    • Authors: Mardiyanto Mardiyanto, Budi Untari, Ady Mara, Sadakata Sinulingga, Nirwan Syarif, Gustina Emilia Ningsih
      Pages: 320 - 326
      Abstract: The pandemic period has caused antibiotics highly recommended to cure infections. The use of macrolide antibiotics has greatly increased recently due to outbreaks of diseases that attack the human respiratory tract all of part of the world. One member of the macrolide group is erythromycin ethyl succinate which has low solubility in water. Therefore, this study aims to convert erythromycin ethyl succinate into lipid nanoparticles in an attempt to increase solubility. The method for the formation of nanoparticles is heating emulsification and homogenization. The results obtained in the form of formula 1 (F1) showed the percent encapsulation of 85.688±0.30641. The physical properties were that it has a size of 398.9±1.4 nm, a PDI of 0.3895±0.0015, and zeta potential of -17.45±0.15 mV respectively. The stability was determined by an accelerated test by the influence of extreme temperature and mechanics affecting the stability of the particles as an indication of decreasing the pH and particle precipitation. The solubility of erythromycin ethyl succinate in the form of lipid nanoparticles was increased in a comparison with the pure substance of erythromycin ethyl succinate.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.320-326
      Issue No: Vol. 7, No. 3 (2022)
       
  • Subclasses of Analytic Functions with Negative Coefficients Involving
           q-Derivative Operator

    • Authors: Andy Liew Pik Hern, Aini Janteng, Rashidah Omar
      Pages: 327 - 332
      Abstract: Let A denote the class of functions f which are analytic in the open unit disk U. The subclass of A consisting of univalent functions is denoted by M. In this paper, we also consider a subclass of M which is denoted by V, consisting of functions with negative coefficients. In addition, this paper also studies the q-derivative operator. By combining the ideas, this paper introduced three subclasses of A with negative coefficients involving q-derivative. Furthermore, the coefficient estimates, growth results and extreme points were obtained for all of these classes.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.327-332
      Issue No: Vol. 7, No. 3 (2022)
       
  • Evaluate All The Order of Every Element in The Higher Even, Odd, and Prime
           Order of Group for Composition

    • Authors: Md. Abdul Mannan, Halima Akter, Md. Amanat Ullah
      Pages: 333 - 343
      Abstract: This paper aims to treat a study on the order of every element in the higher even, odd and prime order of group for composition. In fact, express order of a group and order of an element of a group in real numbers. Here we discuss the higher order of groups in different types of order, which will give us practical knowledge to see the applications of the composition. In order to find out the order of an element am∈G in which an= e= identity element, then find the least common multiple (i.e.(LCM))= λ) of m and n. The least common multiple of two numbers is the "smallest non-zero common number," which is a multiple of both the numbers. So O(am )= λ/m. Also, if G is a finite group, n is a positive integer, and a∈G then the order of the products na. When G is a finite group, every element must have finite order, but the converse is false. There are infinite groups where each element has finite order. Finally, find out the order of every element of a group in different types of the higher even, odd and prime order of group for composition.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.333-343
      Issue No: Vol. 7, No. 3 (2022)
       
  • Electro-adsorption as a Hybrid Processing to Removed Oil from Synthetic
           Oily Solution by Using Activated Carbon and Iron Electrodes

    • Authors: Lia Cundari, Bazlina Dawami Afrah, Suci Dwijayanti, Alvina Suryadinata, Aldi Ramadhani
      Pages: 344 - 352
      Abstract: Biosolar contains oil, fatty acids, emulsifiers, bactericides, and other chemicals. If the oil contents are mixed with water, it will become hazardous waste and affect drinking water sources, endanger human health, air pollution, affect agricultural production, and damage the natural landscape, so the oil content must be processed to reduce its hazardous content. One of the methods used in treating oily solutions is adsorption. The adsorption method for oily solution treatment is ineffective because it requires several stages, so the required capital is relatively larger and takes longer. Electro-adsorption is one of the methods that is being developed for treating oily solutions. Electro-adsorption is a hybrid separation technology to break down oil emulsions in wastewater and some other organic content. The purpose of this study is to characterize the activated carbon and determine the effect of voltage and time on synthetic oily solution treatment in terms of COD value and oil-fat content. A synthetic oily solution is made by mixing 1 g of biosolar/B30 into the water from the Musi River to a volume of 1 L. The application of the electro-adsorption method uses commercially activated carbon as an adsorbent and iron as an electrode. Variations given to the process with voltage 0, 5, 10, 15 V and time 0, 5, 10, 15, 20, and 25 minutes. The characteristic of activated carbon showed a size change in the pore size from 2.58 µm to 1.98 µm and a reduction of surface area from 740 (±180) m2/g to 730 (±120) m2/g. The electro-adsorption method was effective in treating oily solutions. The decrease of COD reaches the maximum level at a voltage 10 V for 25 minutes, which was 75.92% from 62.33 mg/L to 15 mg/L initially, while the concentration of oil-fat obtains the maximum level at a voltage of 5 V for 5 minutes that is equal to 99.65%, initially 303.19 mg/L to 1.05 mg/L. The optimum condition of the electro-adsorption process in synthetic oily solution was at the voltage of 5 V and a time of 5 minutes. The electro-adsorption process is an effective method to treat synthetic oily solutions.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.344-352
      Issue No: Vol. 7, No. 3 (2022)
       
  • Crystal Engineering Approach in Physicochemical Properties Modifications
           of Phytochemical

    • Authors: Dhea Sultana Lutfiyah, Lili Fitriani, Muhammad Taher, Erizal Zaini
      Pages: 353 - 371
      Abstract: Phytochemicals have been used to reduce the risk of diseases and maintain good health and well-being. However, most phytochemicals have a limitation in their physicochemical properties, which can be modified by reforming the shape of the crystals. Therefore, crystal engineering is a promising approach to optimize physicochemical characteristics of the active pharmaceutical ingredients (APIs) in a phytochemical without altering its pharmacological efficacy. Hence, this paper reviews current strategies for the use of crystal engineering to optimize physicochemical properties of phytochemicals, which is followed by the design of the synthesis and characterization of particular phytochemicals, including piperine (PIP), quercetin (QUE), curcumin (CUR), genistein (GEN), and myricetin (MYR). The literature indicates that crystal engineering of multicomponent crystals (MCCs) enhances phytochemical physicochemical properties, including solubility, dissolution rate, stability, and permeability. The MCCs provide a lower lattice energy and noncovalent bonding, which translate into lower melting points and weak intermolecular interactions that generate greater solubility, higher dissolution rate, and better stability of the APIs. Nevertheless, the absence of reported studies of phytochemical crystal engineering leads to a lack of variation in the selection of coformers, methods of preparation, and improvement of physicochemical properties. Therefore, more extensive evaluation of the design and physicochemical characteristics of phytochemicals using MCCs is necessary and manifests the opportunity to enhance the application of phytochemicals in the pharmaceutical industry.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.353-371
      Issue No: Vol. 7, No. 3 (2022)
       
  • Preparation of Hydrochar from Salacca zalacca Peels by Hydrothermal
           Carbonization: Study of Adsorption on Congo Red Dyes and Regeneration
           Ability

    • Authors: Mauizatul Hasanah, Alfan Wijaya, Fitri Suryani Arsyad, Risfidian Mohadi, Aldes Lesbani
      Pages: 372 - 378
      Abstract: Hydrochar of Salacca zalacca peels (HC-SP) is prepared by hydrothermal carbonization treatment of Salacca zalacca peels (SP) obtained from local fruits at Palembang, South Sumatera, Indonesia, with the resulting yield weight reaching 90%. Materials are characterized using the XRD diffraction, FTIR spectrum, and SEM-EDX. The XRD pattern shows the characteristics of the formation of amorphous compounds. The FTIR spectrum confirms the presence of functional groups O-H, C-H, C=C, and C-O. Data of SEM-EDX show that materials have heterogeneous morphologies, form aggregates, and in HC-SP materials there is an increase in carbon content from the initial material. The capacity of SP in the congo red (CR) adsorption process is 33.003 mg/g and increases to 133.333 mg/g in HC-SP. The maximum dye adsorbed was achieved at pH 4. The adsorption kinetics followed PSO with the equilibrium adsorption occurring at 90 minutes, and the adsorption isotherm followed the Langmuir isotherm with the value of R2 closer to the value of 1. A positive 4H value indicated that the adsorption is an endothermic process. In contrast, an 4S value suggested that the degree of irregularity in the adsorption process is small in large concentrations. Based on data regeneration ability, materials of SP and HC-SP can be used in the three cycles regeneration process of the CR adsorption process. The adsorption process of CR occurs physically and chemically based on enthalpy values and FT-IR data after being adsorbed with CR.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.372-378
      Issue No: Vol. 7, No. 3 (2022)
       
  • Validation of Mercury Speciation Analysis in River Around Artisanal
           Small-Scale Gold Mining Area in West Nusa Tenggara, Indonesia

    • Authors: Dhony Hermanto, Nurul Ismillayli, Nindi Herdiyanti, Siti Raudhatul Kamali, Soraya Aulia
      Pages: 379 - 384
      Abstract: A method for determining mercury concentration using a mercury analyzer in a river water sample was validated according to ISO/IEC 17025. Analytical performance including linear range, limit of detection, precision and accuracy were evaluated. Mercury speciation profile was obtained from Pelangan River at three areas within Dusun Rambut Petung, an area with the highest amount of artisanal small-scale gold mining (ASGM) in Lombok, West Nusa Tenggara. Then, their concentration in each species was measured using sequential extraction. Good curve linearity was obtained in the concentration range of 0.1-5.0 µg/L and the limit of detection was 0.014 µg/L. The developed method has good precision and accuracy with a RSD value <10% and a recovery of 94.16-101.91%. The detected fraction of mercury in the Pelangan river is organomercury, elemental mercury, and sulfide-bound species with each concentration of 0.732±0.032; 0.350±0.027; and 0.850±0.027 µg/L, respectively. The measurement results showed conformity with the reference method using CV-AAS. Therefore, this method can be applied to determine mercury levels in water for monitoring environmental quality.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.379-384
      Issue No: Vol. 7, No. 3 (2022)
       
  • Catalytic Oxidative Desulfurization of Dibenzothiophene by Composites
           Based Ni/Al-Oxide

    • Authors: Nur Ahmad, Alfan Wijaya, Amri, Erni Salasia Fitri, Fitri Suryani Arsyad, Risfidian Mohadi, Aldes Lesbani
      Pages: 385 - 391
      Abstract: In the present study, composite layer double hydroxide-metal oxide (Ni/Al-TiO2 and Ni/Al-ZnO) was successfully prepared and used as catalyst of oxidative desulfurization of dibenzothiophene. Characterization of catalyst was used XRD, FTIR, and SEM-EDS. The structure of Ni/Al-LDH, TiO2, and ZnO in composite Ni/Al-TiO2 and Ni/Al-ZnO was consistent, which also indicated that the preparation of composite did not change the form of precursors. FTIR spectra of Ni/Al-TiO2 and Ni/Al-ZnO absorption band at 3398, 1639, 1339, 832, 731, and 682 cm−1. The catalysts have an irregular structure, TiO2 and ZnO adhere to the surface of Ni/Al LDH. The percent mass of Ti and Zn on the composite at 29.3% and 18.2%, respectively. The acidity of Ni/Al LDH increased after being composited with TiO2 and ZnO. The optimum reaction time, dosage catalyst, and temperature were 30 min, 0.25 g, and 50°C, respectively, and n-hexane as a solvent. The percentage conversion of dibenzothiophene on Ni/Al-LDH, TiO2, ZnO, Ni/Al-TiO2, and Ni/Al-ZnO were 99.44%, 91.92%, 95.36%, 99.88%, and 99.90%, respectively. The catalysts are heterogeneous system and the advantage is that can be used for reusability. After 3 times catalytic reactions, the conversion of dibenzothiophene still retains more than 80%, even Ni/Al-TiO2 and Ni/Al-ZnO composites still 97.79% and 98.99%, respectively.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.385-391
      Issue No: Vol. 7, No. 3 (2022)
       
  • Enumerate the Number of Vertices Labeled Connected Graph of Order Seven
           Containing No Parallel Edges

    • Authors: Muslim Ansori, Wamiliana, Fitriani, Yudi Antoni, Desiana Putri
      Pages: 392 - 399
      Abstract: A graph that is connected G(V,E) is a graph in which there is at least one path connecting every two vertices in G; otherwise, it is called a disconnected graph. Labels or values can be assigned to the vertices or edges of a graph. A vertex-labeled graph is one in which only the vertices are labeled, and an edges-labeled graph is one in which only edges are assigned values or labels. If both vertices and edges are labeled, the graph is referred to as total labeling. If given n vertices and m edges, numerous graphs can be made, either connected or disconnected. This study will be discussed the number of disconnected vertices labeled graphs of order seven containing no parallel edges and may contain loops. The results show that number of vertices labeled connected graph of order seven with no parallel edges is N(G7,m, g)l= 6,727×Cm6; while for 7≤g≤ 21, N(G7,m, g)l= kg C(m−(g−6))g−1, where k7 =30,160, k8 = 30,765, k9=21,000, k10 =28,364, k11= 26,880, k12=26,460 , k13 = 20,790, k14 =10,290, k15 = 8,022, k16 = 2,940, k17 =4,417, k18 = 2,835, k19 =210, k20 = 21, k21= 1.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.392-399
      Issue No: Vol. 7, No. 3 (2022)
       
  • Susceptible Vaccine Infected Removed (SVIR) Model for COVID-19 Cases in
           Indonesia

    • Authors: Hanna Arini Parhusip, Suryasatriya Trihandaru, Bernadus Aryo Adhi Wicaksono, Denny Indrajaya, Yohanes Sardjono, Om Prakash Vyas
      Pages: 400 - 408
      Abstract: Analysis of data on COVID-19 cases in Indonesia is shown by using the Susceptible Vaccine Infected Removed (SVIR) in this article. In the previous research, cases in the period March-May 2021 were studied, and the reproduction number was computed based on the Susceptible Infected Removed (SIR) model. The prediction did not agree with the real data. Therefore the objective of this article is to improve the model by adding the vaccine variable leading to the new model called the SVIR model as the novelty of this article. The used data are collected from COVID-19 cases of the Indonesian population published by the Indonesian government from March 2020-April 2022. However, the vaccinated persons with COVID-19 cases have been recorded since January 2022. Therefore the models rely on the period January 2021-March 2022, where the parameters in the SIR and SVIR models are determined in this period. The method used is discretizing the models into linear systems, and these systems are solved by Ordinary Least Square (OLS) for time-dependent parameters. It is assumed that the birth rate and death rate in the considered period are constant. Additionally, individuals who have recovered from COVID-19 will not be infected again, and vaccination is not necessarily twice. Furthermore, individuals who have been vaccinated will not be infected with the COVID-19 virus. The SVIR model has captured 3 waves of COVID-19 cases that are appropriate to the real situation in Indonesia from January 2021-March 2022. Additionally, the reproduction numbers as functions of time have been generated. The fluctuations of reproduction numbers agree with the real data. For further research, different regions such as districts in Java and other islands will also be analyzed as the implication of this research.
      PubDate: 2022-07-28
      DOI: 10.26554/sti.2022.7.3.400-408
      Issue No: Vol. 7, No. 3 (2022)
       
 
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