bluuebunny/crossref_metadata_2025_split huggingface dataset:
Correlation Phenolic Concentration to Antioxidant and Antibacterial Activities of Several Ethanolic extracts from Indonesia
Authors: Sartini S , Djide M N , Nainu F 
Published: November 2019

Abstract
Increasing concerns on the adverse effect of synthetic antioxidants and the emergence of antibiotic-resistant Staphylococcus aureus have become two essential problems to be addressed. To tackle them, exploration of natural resources to discover novel antioxidants and/or antibacterial agents is urgently required. The aim of this research was to investigate the correlation of phenolic and flavonoid contents of extracts to their antioxidant and antibacterial activities. Green tea, green coffee, cocoa pod husks, bee pollen, and rosella calyces were processed and subjected to 80% ethanol-based maceration procedure to obtain extracts with appropriate condition. Each extract was examined for its phenolic and flavonoid concentrations using the Folin–Ciocalteau method and the aluminum chloride colorimetric assay, respectively. Further analysis on the free-radical scavenging potential and antibacterial/antibiofilm activity against S. aureus were carried out. Samples were found to contain total phenolics (TP) and total flavonoids (TF) at different concentrations. The highest level of TP and TF was identified in green tea extract and corresponded to the lowest IC50 against DPPH and the lowest MIC against S. aureus colonies or to their respective biofilm. In contrast, low amounts of TP and TF were found in cocoa pod husks and bee pollen which were further demonstrated high IC50 and high MIC. Collectively, our results suggested the linear correlation of phenolic- and flavonoid contents to the antioxidant and antibacterial/antibiofilm activities of plant extracts. The higher the phenolics and flavonoids level, the better the antioxidant and antibacterial/antibiofilm activities obtained from the corresponding extracts.
Relation between body mass index and position of chest examination as a function of entrance surface dose
Authors: Musdalifah I , Suryani S , Rauf N 
Published: November 2019

Abstract
X-ray is ionic radiation which is now a necessity in the health sector as a tool in establishing diagnosis. Calculation of exposure doses in patients generally only considers gender and age, but from a theoretical point of view, energy absorption will be greater with increasing thickness of material. The thickness of the material in terms of chest examination using X-rays is indicated by position of the examination where the lateral examination makes the material exposed to radiation thicker than the posterioranterior or anteriorposterior examination position, as well as the patient's body mass index. Therefore, the relationship between the position of examination and body mass index to the entrance surface dose is the topic of this study. Analysis of chest examination data in several patients with various examination positions and different body mass indices showed an increase in entrance surface dose with increasing body mass index and examination position. The highest entrance surface dose was observed in patients with lateral examination positions, as well as in patients with large body mass indexes.
Hypocenter determination and focal mechanism solution of May 29 2017 earthquake around Poso, Central Sulawesi, Indonesia
Authors: Massinai M F I , Astuti A P , Kiraman M R B , Massinai M A , Ramdhan M 
Published: November 2019

Abstract
On May 29 2017 earthquake occurred at northwest of Poso, Central Sulawesi, Indonesia with M6.5. BMKG recorded the earthquake occurred on 14:35:23 GMT in 1.270S, 120.450E with depth 13 Km. We determined earthquake location and focal mechanism by re-picked P- and S-wave arrival time on waveform which is recorded on 14 BMKG stations. Earthquake location and focal mechanism were determined by using Hypoellipse code and Azmtak code, respectively. The result shows that earthquake occurred on 14:35:19.23 GMT in 1.31820S, 120.27760E with depth 11.62 Km. Focal mechanism indicates that the fault motion of the earthquake is normal fault with left strike-slip component and the fault direction are strike 2760, dip 740 and slip -350. The earthquake is likely related to Palu Koro Fault.
Bio-markers based oil to source rock correlation and paleo-environmental interpretation: A case study from Talang Akar Formation, South Sumatra Basin, Indonesia
Authors: Syamsuddin E , Jamaluddin  , Maria  , Shehzad K , Wahyuni S 
Published: November 2019

Abstract
Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. This study used 3 crude oil sample and 6 well-cutting obtained from Talang Akar Formation. Biomarkers analysis has been used to determine the depositional environment of Talang Akar Formation. The techniques utilized include gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of normal alkanes, isoprenoids, triterpene, and steranes. The most commonly used, pristine (Pr) to phytane (Ph) ratio is a good indicator of the depositional environment. The results in this research show that Pr/Ph ratios range from 5.90-10.08. Pr/Ph indicating abundant terrigenous plant input deposited under oxic to suboxic conditions. The oil/source rock correlation analysis using biomarker data shows that the oils field is correlated with the oils in source rock of Talang Akar Formation. This study concludes that the source rock in Talang Akar Formation was deposited in a transitional (Fluvio-deltaic) to marginal marine environment under oxic conditions.
Implementation Technique of Radiotherapy Patients Dose Verification 3DCRT and IMRT
Authors: Rusydi M , Abdullah B , Tahir D 
Published: November 2019

Abstract
The implementation of Patient Dose Verification Techniques 3DCRT and IMRT aims to guarantee that the dosing shines in accordance with planning the therapy conducted in TPS (Treatment Planning System). Research carried out using Variant types of Clinac CX in Radiotherapy Unit hospital Wahidin Sudirohusodo Makassar. Verify patient dose measurement is done using a dose point and a dose plannar by taking 10 cancer patients cervix 3DCRT techniques and 10 engineering nasopharynx cancer patients IMRT. Results of the study 10 point dose cervix cancer patients techniques 3DCRT retrieved the deviation between -0.005% to 0.243%, an average deviation -0.234%, standard deviation -0.186, and CL 0.364. While in nasopharynx cancer patients IMRT technique obtained the deviation between -1,385% to 1.652%, an average deviation 0.146%, standard deviation 0.015, and CL 0.174. Dose plannar measurement 10 samples of cancer patients cervix engineering 3DCRT retrieved gamma index 3% 3 mm on average of 97.26%, standard deviation 0.063, CL 2.772 and 2 mm 2% average 85.91%, standard deviation of 0.007, CL 15.17. While in nasopharynx cancer patient with IMRT techniques acquired gamma index 3% 3 mm average 97.00%, standard deviation 0.016, CL 3.03 and 2% 2 mm average 83.38%, standard deviation 0.016, and CL 16.65.
Upcoming-wave equation of seismic migration
Authors: Sea J G , Liu G , Aswad S 
Published: November 2019

Abstract
Upcoming-wave is the basis of several seismic migration methods that use the principle of 1-way-time by propagating only from the event point to the receiver. The migration method that uses this upcoming wave theory is the finite difference migration and Fourier transformation migration. In this paper, we will elaborate how the theories of these two migrations are related and described from scalar wave equations to various forms of upcoming wave approximations, both differential equation form of space-time (x-t) and frequency - wave number (f-k) form, along with their transformations.
Prediction of land use and land cover (LULC) changes using CA-Markov model in Mamuju Subdistrict
Authors: Risma  , Zubair H , Paharuddin  
Published: November 2019

Abstract
Changes in land use and land cover (LULC) are one of the changes that are directly affected by human activities which are largely driven by socio-economic factors. Knowing, analyzing and modeling LULC change transformation plays an important role in planning, management and decision making activities. The purpose of this study is to develop LULC projection models using CA-Markov analysis to predict LULC in 2034 in Mamuju Subdistrict as the city centre of Mamuju Regency which has a rapid change in LULC. Inputs used in this research are data on river networks, roads, public facilities, LULC 2009, LULC 2014 and LULC 2019. The results showed that for 25 years (2009-2034) forest dominated land cover in Mamuju Subdistrict and settlement into LULC classes which has increased. In 2034, settlements have an area of 5.88% of the total study area or grow by 4.93% over the period of 2009-2034. The CA-Markov model used in predicting LULC changes was validated and produced a kappa coefficient of 0.969 (96.9%) which showed that the model had successfully predicted LULC changes in the study area.
Extended Cox model for breast cancer survival data using Bayesian approach: A case study
Authors: Arsyad R , Thamrin S A , Jaya A K 
Published: November 2019

Abstract
Breast cancer (carsinoma mammae) is one type of cancer that occurs due to abnormal breast cell growth. Some of the factors that are thought to trigger breast cancer include the unhealthy lifestyles. The existence of these factors indicates that there is a correlation between breast cancer and patient survival. One of method for analyzing survival data is Cox proportional hazard. Cox proportional hazard model implies that each covariate is proportional. But in reality, there are often cases where there is a disproportionate covariate, in the sense that there is a relationship with the time, called time dependent covariate. In this case an extended of the Cox proportional hazard model needs to be done. Therefore, the aim of this paper to determine the relationship between the breast cancer patients’ survival time and the factors that influence it using extended Cox model with Bayesian approach. This methodology is applied to breast cancer survival data from Hasanuddin University hospital in Makassar, Indonesia, for the period 2005-2018. The result shows the factors that substantially affect the breast cancer patients’ survival time are marital status, histology, and leukocyte levels.
Likelihood Construction of Hawkes Process in Insurance Claim Settlement Process
Authors: Ilyas N , Sunusi N , Anisa  , Sahriman St 
Published: November 2019

Abstract
The construction of the likelihood equation in the point process models plays a very important role, especially to obtain a good estimator of the parameters of a model. This paper aims to construction of the likelihood of Hawkes process in solving the problem of the claim filing process in the nonlife insurance company. In the construction process, the excitation function with exponential decay is used. The result shows that the total likelihood function of the process depend on probability no claim at time t, the number of policyholder at time t, and the excitation function.
Liu-type regression in statistical downscaling models for forecasting monthly rainfall salt as producer regions in Pangkep regency
Authors: Sahriman St , Anisa  , Koerniawan V 
Published: November 2019

Abstract
Liu-Type Regression (LTR) is one of the statistical methods to overcome multicollinearity in multiple regression models. LTR is the development of Ridge regression and Liu estimator. When there is a strong collinearity, selected k parameter in the ridge regression does not fully overcome the multicollinearity. This study aimed to estimate the rainfall data in Pangkep Regency (as response variable) with LTR approach on Statistical Downscaling (SD) models. Precipitation (as predictor variables) is the result of a simulation of a grid on the Global Circulation Model (GCM). This study uses a size 8 8 grid of GCM (64 predictor variables) over an area of Pangkep Regency so that there is a high multicollinearity. Three dummy variables were determined from k-means cluster technique used as predictor variables to overcome the heterogeneity of residual variance. LTR model with dummy variables are able to explain the diversity of rainfall data properly. The value of R2 produced ranges 85.23% -88.99% with Root Mean Square Error (RMSE) ranges 117.732-136.377. Validation of the model generates a high correlation value between the actual rainfall and alleged rainfall period of 2017 (about 0.977-0.979). The value of Root Mean Square Error Prediction (RMSEP) produced lower (about 57.625-61.120). SD analysis was also performed with and without the dummy variable in the Ridge regression and LTR. In general, LRT models with dummy (k = 0.652, d = -0.799) is the best model based on the value of R2, RMSE, correlation, and RMSEP.
Relative equilibria in curved restricted 4-and 5-body problems
Authors: Alhowaity Sawsan , Shoaib Muhammad 
Published: November 2019

Abstract
We consider a 5-body problem on 2-dimensional surfaces of constant curvature κ, with four of the masses arranged at the vertices of a square and the fifth mass at the north pole of the sphere. The five-body set up is discussed for κ
> 0 and for κ
< 0. When the curvature is positive, it is shown that relative equilibria exists when the four masses at the vertices of the square are either equal or two of them are infinitesimal such that it doesn’t effect the motion of the remaining three masses. However with two pairs of masses at the vertices of the square, no relative equilibria exists. In the hyperbolic case, κ
< 0, there exist two values for the angular velocity which produce negative elliptic relative equilibria when the masses at the vertices of the square are equal. We also show that the solutions with non-equal masses do not exist in H2.
MHD Flow and Heat Transfer of Ferrofluid on Stagnation Point along Flat Plate with Convective Boundary Condition and Thermal Radiation Effect
Authors: Yasin S H M , Mohamed M K A , Ismail Z , Widodo B , Salleh M Z 
Published: November 2019

Abstract
This theoretical study deals with numerical solution of MHD convection laminar boundary layer flow and heat transfer on stagnation point along a stationary horizontal flat plate. For this purpose, ferrofluid which contains magnetite, Fe3O4 as a ferroparticles and water as a base fluid is considered. Ferrofluid has shown a particular achievement when the effect of external magnetic field applied, such as helping to control the properties of physical and flow of ferrofluid. The study starts with the formulation of the mathematical equations that governed the ferrofluid flow and heat transfer. The governing equation which is in the form of dimensional nonlinear partial differential equations are reduced to nonlinear ordinary differential equations by using appropriate similarity transformation and then solved numerically by using the Keller-box method. Numerical result is discussed in terms of pertinent effects that influence the ferrofluid flow and heat transfer like magnetic parameter, ferroparticles volume fraction parameter, Biot number and radiation parameter on velocity and temperature profiles. It is found that the temperature profile increase with an increase volume fraction of ferroparticles parameter, radiation parameter and Biot number and decrease with increasing magnetic parameter.
Thermal Radiation Effect on MHD Stagnation Point flow of Williamson Fluid over a stretching Surface
Authors: Hashim Hasmawani , Anuar Mohamed Muhammad Khairul , Ishak Nazila , Sarif Norhafizah Md , Salleh Mohd Zuki 
Published: November 2019

Abstract
Thermal radiation effects on MHD stagnation point flow of Williamson fluid over a stretching surface are studied. With the help of similarity transformation, the governing equations are converted to nonlinear ordinary differential equations and then solved numerically by Runge-Kutta-Fehlberg (RKF) technique. Numerical results for the reduced Nusselt number and reduced skin friction coefficient as well as the temperature and velocity profiles are elucidated through tables and graphs. The influence of Prandtl number, stretching parameter, Williamson fluid parameter, thermal radiation parameter and magnetic parameter are analyzed and discussed. It is found that, as Prandtl number and magnetic parameter increase, the temperature profiles decrease. Meanwhile, as Williamson fluid parameter and thermal radiation parameter decrease, the temperature profile increase.
Numerical Solutions of MHD Stagnation-Point Flow over an Exponentially Stretching/Shrinking Sheet in a Nanofluid
Authors: Rahman A N H , Bachok N , Rosali H 
Published: November 2019

Abstract
This present paper analyses the steady 2-D stagnation-point flow over an exponentially stretching/shrinking sheet in nanofluids with the effect of magnetohydrodynamic (MHD). The effect of nanoparticles volume fraction parameter φ, and the stretching/shrinking sheet parameter ε was analysed over metallic nanoparticles namely as copper (Cu) in the based fluid of water with Prandtl number Pr = 6.2. The problem was solved numerically by using a similarity transformation to transform the governing partial differential equations into nonlinear ordinary differential equations and then solved using the boundary value problems solver bvp4c in Matlab software. The results reveal that the shrinking sheet is non-unique while the stretching sheet is unique. Thus, with the increment of the magnetohydrodynamic, the range of solutions is expended. As the magnetic field parameter increase, the skin friction and heat transfer also increase.
Mathematical Modelling and Simulation of the Performance of PV/T Air Solar Collector
Authors: Wahida Khalili Noran Nur , Othman Mahmod , Abu Bakar Mohd Nazari , Sakidin Hamzah , Abdullah Mohd Lazim 
Published: November 2019

Abstract
The world demand of energy is increasing continuously, and solar energy is one of the renewable energies that can be utilized to fulfil the demand. Over the years, there are many researches that have been carried out on hybrid air solar collector. Hybrid-PV system or PV/T system is an integration of photovoltaic (PV) cells and solar thermal components. It is proven in many researches that combined PV and thermal system gives higher efficiency than individually working system. Therefore, this paper discusses the development of mathematical model of a photovoltaic/thermal (PV/T) solar collector. The effects of various parameters on the performance of the solar collector are also discussed. Since there is a drop of efficiency of the photovoltaic cells as the operating temperature increases, this study proposes a design of PV/T solar collector with an air-cooling system with a set of fins attached to improve its overall performance. A mathematical model representing the system by using one dimensional energy balance equations is developed. A simulation has been carried out by using MATLAB to determine the effect of parameters such as solar radiation and temperature on the performance of the solar collector. It is found out that when the temperature of the collector is reduced by removing heat through working fluid, its performance can be improved. Therefore, when air mass flow rate increases, the electrical and thermal efficiencies of the collector increase. Meanwhile, the collector efficiency also increases with the increase in solar radiation.
Autonomous Navigation on Modified AOR Iterative Method in Static Indoor Environment
Authors: Dahalan A. A. , Saudi A. , Sulaiman J. 
Published: November 2019

Abstract
One of the main issues when dealing with mobile robot navigation is that we have to resolve the obstacle avoidance problem, where when moving from a starting point to the goal point, the mobile robot will have to generate a collision-free path in order ensure that it can move efficiently in the environment. In this study, we attempt to resolve the issue by solving it iteratively via numerical technique. This solution is based on the potential field method that utilizes the Laplace’s equation to constrain the generation of potential functions over the regions in the configuration space where the mobile robot operates in. This paper proposed Modified Accelerated Over-Relaxation (MAOR) iterative method for solving robot path planning problem. Through the application of finite-difference technique in it, the experiment shows that the mobile robot is able to generate a smooth path from starting point to goal point. Furthermore, the results obtained from the simulation has shown that this numerical method was able to perform faster solution and generated smoother path comparing the previous works on the similar problem.
Solving Duffing Type Differential Equations using a Three-Point Block Variable Order Step Size Method
Authors: Nurullah Rasedee Ahmad Fadly , Abdul Sathar Mohammad Hasan , Asbullah Muhammad Asyraf , Feng Koo Lee , Jin Wong Tze , Ishak Norizarina , Hamzah Siti Raihana 
Published: November 2019

Abstract
This research proposes a three-point block method for solving Duffing type higher order ordinary differential equations (ODEs) which is also commonly referred as the Duffing oscillator. The research conducted implements a variable order step size technique for approximating the exact solution for the Duffing Oscillator. The proposed algorithm will be tested against various Duffing oscillators and numerical approximation will be compared with current viable methods. The accuracy and efficiency of the proposed method will be illustrated in the numerical results.
Effect of suction on the MHD fluid flow past a non-linearly stretching/shrinking sheet: Dual solutions
Authors: Hafidz Hafidzuddin Mohd Ezad , Naganthran Kohilavani , Nazar Roslindar , Arifin Norihan Md 
Published: November 2019

Abstract
This paper investigated the effects of suction for incompressible magnetohydrody-namics (MHD) fluid over a non-linearly stretching/shrinking sheet. A proper similarity trans-formation has been used to reduce the system of partial differential equations to a system of ordinary differential equations, which was then solved numerically by using the bvp4c function in the MATLAB software. Dual solutions are found for certain values of the suction parameter when the sheet is shrinking. The generated results were presented and discussed in the relevance of the governing parameters.
Analytical Solution of Ordinary Fractional Differential Equations by Modified Homotopy Perturbation Method and Laplace Transform
Authors: Hailat Ibrahim , Nemrat Asem AL , Zainuddin Zarita , Azmi Amirah Binti 
Published: November 2019

Abstract
In this paper, a modified Laplace transform homotopy perturbation method (MLT-HPM) is used to find the approximate solution of ordinary fractional differential equations(OFDEs). The proposed method is developed to improve the accuracy of the approximate solutions provided by the LT-HPM method. The appropriate initial approximation will be chosen, furthermore, the residual error will be cancelled at several points of the interest interval (RECP). A couple of OFDEs are considered in order to demonstrate the effectiveness of the suggested method. Comparisons are made with the results obtained from LT-HPM, continuous analytical method (CAM), modified homotopy analysis method (MHAM), and modified optimal homotopy analysis method (MOHAM). The resulting solutions require only a first order approximation of MLT-HPM, compared to LT-HPM, which requires more iterations for the same examples studied.