Communications in Science and Technology
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Published By Komunitas Ilmuwan Dan Profesional Muslim Indonesia (Kipmi)

2502-9266, 2502-9258

2021 ◽  
Vol 6 (2) ◽  
pp. 101-106
Author(s):  
Nguyen Van Chuong

This research found the great hold of liming, soils and irrigation water on the arsenic (As) accumulation of rice, maize and mung bean in the nethouse research. Two greenhouse experiments had various plant types of rice, maize and mung bean with two soils inside and outside the dyke, two irrigated waters of 0.0 and 200 ?g As/L and three different lime ratios (0, 7.0 and 9.0 tons CaO/ha). The whole treatments were twenty one (12 treatments of experiment 1 and 9 of experiment 2) with 4 repetitions. The results of this study showed that the lime application raised both soil pH and crop yield. The arsenic (As) absorption of plant bodies in stems and seeds inside the dyke increased from 67.8 to 68.3% higher than those outside the dyke, respectively. The arsenic contents of stems and seeds with the treatments of 200 ?g As/L irrigation water were higher from 81.5 to 89.4% than that of non As irrigation water, respectively. The lime supplementation of 7.0 and 9.0 tons CaO per ha reduced the As accumulation of stems and seeds of rice, maize and mung bean was lower than the one without lime supplement from 38.6 (stems) and 54.5 (seeds). Mung bean absorbed the highest As, followed by rice and maize with the lowest As value. However, the lime supplementation of 9.0 tons CaO/ha had so high soil pH of soil that restricted the growth and yield of crops. More different lime concentrations need to search for more new details and new discovery of positive effects of this research.


2021 ◽  
Vol 6 (2) ◽  
pp. 74-79
Author(s):  
Patimah Mega Syah Bahar Nur Siregar ◽  
Normah ◽  
Novie Juleanti ◽  
Alfan Wijaya ◽  
Neza Rahayu Palapa ◽  
...  

In this study, chitosan was extracted from shrimp shells by demineralization and deproteination processes. The extracted chitosan was used to modify the layered double hydroxide and used as an adsorbent for the removal of congo red from aqueous solutions. Composites were successfully synthesized using M2+/Al (M2+ = Zn, Mg, Ni) and chitosan (CH) and the samples obtained were characterized using XRD and FTIR. The X-ray diffraction (XRD) pattern appeared at the layered double hydroxide peak of 2? = 11.63°; 23.00°; 35.16°; and 61.59° and chitosan at 2? = 7.93° and 19.35. The composite appearing in the layered double hydroxide and chitosan indicated that the composite material has been successfully synthesized. The XRD diffraction patterns of Zn/Al-CH, Ni/Al-CH, and Mg/Al-CH showed low crystallinity. The Fourier Transform Infrared (FTIR) spectra verifying absorption spectrum showed the presence of two bands at 3448 cm-1, 1382cm-1 characteristic to both chitosan and LDH. Adsorption of Congo Red (CR) followed the pseudo-second-order and Langmuir isotherm models. The adsorption capacities of Zn/Al-CH, Ni/Al-CH, and Mg/Al-CH were 181.818 mg/g, 227.273 mg/g, and 344.828 mg/g, respectively. The layered double hydroxide-chitosan composite adsorption was endothermically characterized by positive enthalpy and entropy values. On the other hand, the adsorption spontaneously was characterized by a negative Gibbs free energy value. The composites in this study were formed from LDH modified from chitosan extracted from shrimp shells to form Zn/Al-CH, Ni/Al-CH, and Mg/Al-CH. The results of the characterization showed a number of characteristics that resembled the constituent materials in the form of LDH and chitosan. After being applied as an adsorbent to absorb Congo red dye, it then showed the most effective results using Mg/Al-CH adsorbent with an adsorption capacity of 344.828 mg/g.


2021 ◽  
Vol 6 (2) ◽  
pp. 91-100
Author(s):  
Firmansyah Nur Budiman ◽  
Ali Muhammad Rushdi

Partial discharges (PDs) constitute important phenomena in a Gas-Insulated System (GIS) that warrant recognition (and, subsequently, mitigation) as they are obvious symptoms of system degradation. This paper proposes the application of dimensional analysis, based on Buckingham pi theorem, for characterizing PDs provoked by the presence of metallic particles adhering to the spacer surface in a GIS employing SF6 (Sulphur hexafluoride). The ultimate goal of the analysis is to formulate the relationships that express three PD indicator quantities, namely current, charge, and energy, in terms of six independent quantities that collectively influence these indicators. These six quantities (henceforth referred to as the influencing, determining or affecting variables) include the level of applied voltage, the SF6 pressure, the length and position of the particle on the spacer, the duration of voltage application, and the gap between electrodes. To compute the pertinent dimensionless products, we implement three computational methods based on matrix operations. These three methods produce exactly the same dimensionless products, which are subsequently used for constructing the models depicting the relationships between each of the three PD dependent quantities and the common six determining variables. The models derived provide partial quantitative information and facilitate qualitative reasoning about the considered phenomenon.


2021 ◽  
Vol 6 (2) ◽  
pp. 117-124
Author(s):  
Satyanto Krido Saptomo ◽  
Rudiyanto ◽  
Muhamad Askari ◽  
Chusnul Arif ◽  
Willy Bayuardi Suwarno ◽  
...  

Sheet pipe is a type of perforated pipe used for drainage designed initially for drainage but has the potential for sub-surface irrigation. The objectives of this study were to experiment and observe the performance of the sub-surface irrigation control system with sheet pipe. This investigation covered the observation of water table control and its effect on soil moisture. The detailed process of water flow during the setting of the water table was numerically modeled in 2 dimensions to observe the distribution of soil moisture, soil pressure, and flux. The results showed that the system successfully controlled the water table at the desired level in the experiment. The developed two-dimensional numerical simulation showed the distribution of soil moisture in the model center as a response to the water table increase, represented by the variable head. The soil wetting advances toward soil surface driven by the water table, which was increased gradually and reached saturation at the height of water table setpoint.


2021 ◽  
Vol 6 (2) ◽  
pp. 107-116
Author(s):  
Adewunmi Olaniran Adeyemi ◽  
Eno Emmanuella Akarawak ◽  
Ismail Adedeji Adeleke

Many existing distributions in literatures does not have the modeling fits capacity to adequately describe the real-life phenomena. The Exponential Pareto (EP) distribution has further gained some generalizations among several authors using different generator techniques with an aim to obtain a new distribution with greater flexibility. This article proposes Gompertz Exponential Pareto (GEP) distribution using the Gompertz generator. Findings from the study revealed some lifetime distributions as special cases and mathematical properties of the distribution investigated including the mean, variance, coefficient of variation, quantile, moment, moment generating function and, order statistics. The distribution can be positively or negatively skewed. It is unimodal with failure rates whose shapes could be reversed J bathtub, constant, decreasing and, increasing and the parameters were estimated using maximum likelihood estimation approach. Applications to two real-life datasets revealed the ability of GEP distribution to provide more flexibilities and better fit to the dataset compared to some previously proposed distributions for the data. The results also revealed that GEP had the superior performance over other generalizations of EP distribution existing in literatures and the performance has further strengthened the usefulness of the Gompertz-generator technique.


2021 ◽  
Vol 6 (2) ◽  
pp. 69-73
Author(s):  
Ari Sulistyo Rini ◽  
Averin Nabilla ◽  
Yolanda Rati

This study aims to investigate the physical characteristics and photocatalyst activity of biosynthesized ZnO with pineapple (Ananas comosus) peel extract under microwave irradiation. The ZnO powder was prepared in two different concentrations of zinc nitrate hexahydrate (ZNH) at 200mM (Z-200) and 500 mM (Z-500). The optical, structural, and morphological properties of ZnO were analyzed using UV-Vis spectroscopy, X-Ray Diffraction (XRD), and Scanning Electron Microscopy (SEM), respectively. The UV-Vis absorption spectrum showed a wide absorbance peak of ZnO at the wavelength of 300-360 nm with a bandgap energy of 3.22 and 3.25 eV. The XRD result confirmed the wurtzite structure of ZnO with high crystallinity. SEM morphology showed spherical particles with an average particle size of 190-220 nm. For photocatalytic application, ZnO film was fabricated via the doctor blade method from microwave-assisted biosynthesized ZnO powder. ZnO films were then applied under UV-irradiation to examine the photocatalytic degradation of methylene blue. It was found that the catalytic behavior of ZnO film was affected by the starting ZNH concentration with maximum effectiveness of 46% degradation after 2 h.


2021 ◽  
Vol 6 (2) ◽  
pp. 80-90
Author(s):  
Yulian Firmana Arifin ◽  
Muhammad Arsyad ◽  
Jeane Monica ◽  
Setianto Samingan Agus

Water containing sulfuric acid with a pH up to 3 is prevalent in swampy areas. This article focuses on the effects of the solution on volume change of compacted claystone?bentonite mixture. Claystone was obtained from Banjarbakula landfill and it was mixed with bentonite on a 5, 10, 15, and 20% dry mass basis. Samples possessed the dry density of 16 kN/m3 and moisture content of 10, 15, and 20%. The odometer examined the samples' swelling and compression in both pure and acidic water. Characterization tests i.e., XRF, XRD, and FTIR were also performed. The results showed that swelling and compression were affected by initial moisture and bentonite content. Samples with a moisture content of 20% showed compression in acidic water. Acidic water changed the water absorbed on the clay surface without altering the mineral. A mixture containing 20% bentonite compacted to optimum moisture content was found at best in reducing the acidic water effects.


2021 ◽  
Vol 6 (2) ◽  
pp. 60-68
Author(s):  
Primata Mardina ◽  
Hesti Wijayanti ◽  
Abubakar Tuhuloula ◽  
Erita Hijriyati ◽  
Sarifah

The utilization of an appropriate catalyst in biodiesel production depends on the free fatty acid content of vegetable oil as a feedstock. Recently, heterogeneous acid catalysts are widely chosen for biodiesel production. However, these catalysts are non-renewable, highly expensive and low stability. Due to the aforementioned drawbacks of commercial heterogeneous acid catalyst, a number of efforts have been made to develop renewable green solid acid catalysts derived from biomass. Published literature revealed that the application of the biomass derived solid acid catalysts can achieve up to 98% yield of biodiesel. This article focused on corncob as raw material in solid acid catalyst preparation for biodiesel production. The efficient preparation method and performance comparation are discussed here. The corncob derived heterogeneous acid catalysts provides an environmentally friendly and green synthesis for biodiesel production.


2021 ◽  
Vol 6 (1) ◽  
pp. 35-40
Author(s):  
Rian Adam Rajagede ◽  
Rochana Prih Hastuti

In the process of verifying Al-Quran memorization, a person is usually asked to recite a verse without looking at the text. This process is generally done together with a partner to verify the reading. This paper proposes a model using Siamese LSTM Network to help users check their Al-Quran memorization alone. Siamese LSTM network will verify the recitation by matching the input with existing data for a read verse. This study evaluates two Siamese LSTM architectures, the Manhattan LSTM and the Siamese-Classifier. The Manhattan LSTM outputs a single numerical value that represents the similarity, while the Siamese-Classifier uses a binary classification approach. In this study, we compare Mel-Frequency Cepstral Coefficient (MFCC), Mel-Frequency Spectral Coefficient (MFSC), and delta features against model performance. We use the public dataset from Every Ayah website and provide the usage information for future comparison. Our best model, using MFCC with delta and Manhattan LSTM, produces an F1-score of 77.35%


2021 ◽  
Vol 6 (1) ◽  
pp. 55-59
Author(s):  
Yahya Dwikarsa ◽  
Abdul Basith

The scale value is an important part of the segmentation stage which is part of Object-Based Image Analysis (OBIA). Selection of scale value can determine the size of the object which affects the results of classification accuracy. In addition to setting the scale value (multiscale), selection of machine learning algorithm applied to classify shallow water benthic habitat objects can also determine the success of the classification. Combination of setting scale values and classification algorithms are aimed to get optimal results by examining classification accuracies. This study uses orthophoto images processed from Unmanned Aerial Vehicle (UAV) mission intended to capture benthic habitat in Karimunjawa waters. The classification algorithms used are Support Vector Machine (SVM), Bayes, and K-Nearest Neighbors (KNN). The results of the classification of combination are then tested for accuracy based on the sample and Training Test Area (TTA) masks. The result shows that SVM algorithm with scale of 300 produces the best level of accuracy. While the lowest accuracy is achieved by using SVM algorithm with scale of 100. The result shows that the optimal scale settings in segmenting objects sequentially are 300, 200, and 100


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