bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of formamidinium cation on electronic structure of formamidinium lead iodide
Authors: Sukmas Wiwittawin , Nedkun Piyanooch , Pinsook Udomsilp , Tsuppayakorn-aek Prutthipong , Bovornratanaraks Thiti 
Published: December 2019

Abstract
The emergence of hybrid organic-inorganic perovskites (HOIPs) have attracted considerable attention due to their electronic and optical properties leading to potential applications, especially photovoltaics technology. The effects of the Formamidinium cation (HC(CH2)2
+) or FA cation on cubic/α-Formamidinium lead iodide (HC(CH2)2PbI3) or α-FAPI were thoroughly and systematically investigated. We calculated the electronic band structures and the density of states of FAPI and FAPI without the FA cation including spin-orbit coupling interactions based on the state-of-the-art density functional theory (DFT). The results suggest that, according to the band structures, the FA cation exhibits a couple of nearly non-dispersive bands, whereas it is revealed that the organic cation weakly interacts with the inorganic framework of PbI3 octahedral cage.
Effect of quantum well width on the electron and hole states in different single quantum well structures
Authors: Rueangnetr N , Sivalertporn K 
Published: December 2019

Abstract
In this study the electron and hole states in Al0.33Ga0.67As/GaAs single quantum well structures including squared QW, step QW and tilted QW, have been theoretically studied by solving the Schrodinger equation in real space. The energies and wave functions of electron and hole are calculated for different well widths. It is found that energy level of electron and hole decreases with increasing the well width. Adding step or tilted layers gives rise to the decrease of electron and hole energy levels. The ground state energy level in a tilted single quantum well structure is lower than that in a step single quantum well structure. It is also found that the energy of electron and hole ground states do not change as the width of step layer increase. This is because the ground state occupies in a lower well only. The wave functions are symmetric (ground state) and antisymmetric (the first excited state). The maximum of ground state wave function is at the central of the well and the probability of finding electron and hole in excited states are different in each region. The hole levels are lower than the electron levels due to the lower well depth and higher mass of hole compared to electron.
A free solution to the Dirac equation in R-spacetime
Authors: Angsachon T , Dhanawittayapol R , Kritsarunont K , Manida S N 
Published: December 2019

Abstract
In this work, the Dirac equation and its solution for a free fermion in R-spacetime is presented. In the solution obtained, the oscillation frequency increases as t → 0+. The time singularity and the necessity of restricting the time domain in R-spacetime is discussed. Limiting the time domain implies the possibility of quantization of the solution, though this is a subject for further work.
Radiological hazard assessment and excess lifetime cancer risk evaluation in surface soil samples collected from Ban Chang and Nikhom Phatthana districts in Rayong province, Thailand
Authors: Kessaratikoon P , Jewawongsakul J , Boonkrongcheep R , Pholthum S 
Published: December 2019

Abstract
Specific activity of natural (40K, 226Ra and 232Th) and anthropogenic (137Cs) radionuclides have been measured and analyzed in 27 surface soil samples in Rayong province in the eastern region of Thailand where is the home of the Southeast Asia industrial estate and one of the largest petrochemical plants in the world. Such high activity concentrations might be associated with the increase in cancerous patients who live in the studied area. All surface soil samples were collected from Ban Chang (12 samples) and Nikhom Phatthana (15 samples) districts in Rayong province. The average specific activities were analyzed and estimated by employing hyper-pure germanium (HPGe) detector and gamma-ray spectrometry analysis system. It was found that the frequency distribution of specific activities of 40K, 226Ra, 232Th and 137Cs for the investigated area were asymmetrical distribution with the skewness of 1.09, 1.54, 0.39 and 0.42, respectively. The median values of specific activities of 40K, 226Ra, 232Th and 137Cs in Bq/kg were 423.75 ± 11.30, 96.65 ± 2.16, 36.73 ± 1.06 and 1.32 ± 0.24 Bq/kg, respectively. In addition, four radiological hazard indices which are gamma-absorbed dose rate (D), radium equivalent activity (Raeq), external hazard index (Hex) and annual external effective dose rate (AEDout) were also studied and assessed by using the measured (median) values of specific activities. Furthermore, the excess lifetime cancer risk (ELCR(outdoor)) could be evaluated by using the AEDout value. The results were also compared with the Office of Atoms for Peace (OAP) annual report data, Thailand and global radioactivity measurement and calculations. Moreover, the radioactive contour maps of the investigated area were also created and presented in this paper. From this study, value for D was higher than the worldwide average value (84.98 ± 2.12 nGy/h). The AEDout and ELCR(outdoor) values were equal to 0.10 ± 0.003 mSv/y and (0.39 ± 0.01)×10-3, respectively and lower than the worldwide average. Further studies and evaluations need to assess the real risks and effects to people health.
Low dose gamma radiation effects on seed germination and seedling growth of cucumber and okra
Authors: Jaipo N , Kosiwikul M , Panpuang N , Prakrajang K 
Published: December 2019

Abstract
Cucumber and okra seeds were radiated by Co-60 gamma radiator for 50, 100, 150 and 200 Gy. Germination percentage and seedling growth were observed every day for 10 days. After 10 days of seedling growth, weight of fresh and dry seedling were measured. The result showed that the highest germination percentage of cucumber was 100% on the third day of 50 Gy gamma-radiated seeds. The highest germination percentage of okra was 100% on the fifth day of 50 Gy gamma-radiated seeds. The highest seedling lengths of cucumber and okra were 13.7 cm. and 9.4 cm. with 50 Gy and 200 Gy of gamma dose, respectively. Weight of fresh and dry seedings showed no trend corresponding to the seedling growth. This study shows that the low dose gamma radiation may enhance the germination rate and the seedling growth during the early seedling state of some vegetable seeds.
An effect of finite reservoir size on pressure gradient generation in a pinched injection sample plug generation in cross design electroosmotic microfluidic device
Authors: Chimsiri P , Chaiwong C , Tongbai C , Pussadee N 
Published: December 2019

Abstract
In performing microfluidic electrophoresis, sample loading must be prioritized since the shape of the initial sample plug injected into the separation channel immensely influences the electrophoretic separation efficiency. Non-zero pressure gradient due to different liquid level in finite size reservoirs is generated as a result of continuous electroosmotic flow (EOF) pumping, resulting in undesired parabolic pressure profile both in the same and opposite direction of sample propagation. This issue could be alleviated by fabricating larger reservoirs which can maintain the liquid level due to gradual volume changing as time elapses. This work presents experimental and numerical study on effect of 3.5 – 8.0 mm reservoir size on Rhodamine B plug flow generation from pinched injection sample loading method in cross design microfluidic device. COMSOL Multiphysics AC/DC module was used in calculating electric field distribution from desired applied voltages. The shapes of the injected sample plugs in the beginning of separation step were studied by varying the time of injection step. The experimental result shows that long-tailed sample plug and pressure profiles were generated when the injection time is 2 minutes or more. For the 8 mm diameter reservoirs, the flow profile illustrates pure EOF plug flow when the injection time does not exceed 1.5 minutes. This implies pressure gradient is virtually disappeared. The result of this study will be later applied for protein transferrin electrophoretic separation.
Electronic structure of nontoxic-inorganic perovskite: CsMgBr3 using DFT calculation
Authors: Kaewmeechai Chaiyawat , Laosiritaworn Yongyut , Punya Jaroenjittichai Atchara 
Published: December 2019

Abstract
We introduce the new perovskite material, CsMgBr3, which is composed of pure nontoxic-inorganic elements by substitution of Cs+ and Mg2+ instead of CH3NH3+ and Pb2+ in a well-known CH3NH3PbI3 perovskite. This study was extracted by using the density functional theory (DFT) with Hybrid functional of Heyd-Scuseria-Ernzerhof (HSE) and the generalized gradient approximation (GGA). The band structures of three diferent phases of CsMgBr3 including α, β and γ- phases reveal that the band gaps of these material are in the ultraviolet region (UV). We found that only γ-phase is the direct band gap material, while others are the indirect band gap materials. The results of efective masses of these compounds show that the mobility of hole is lower than that of electron and the α-phase has the highest hole and electron mobility.
Beam characterization for neutron imaging after installation of the external collimator at TRR-1/M1
Authors: Wonglee S , Chulapakorn T , Pornroongruengchok W , Liamsuwan T , Khaweerat S , Channuie J , Picha R 
Published: December 2019

Abstract
The neutron imaging facility at Thai Research Reactor-1/Modification 1 (TRR-1/M1), located at Thailand Institute of Nuclear Technology (Public Organization) has been improved for non-destructive characterization of internal structure of materials. The aims are to study the beam characteristic after an installation of the external collimator, and to optimize the exposure condition for a new setup. The neutron imaging setup was modified to increase the L/D ratio. As a consequence of the extended distance from the beam port to the sample position, an external collimator was installed to focus the neutron beam since 2018. Moreover, a new sample holder was installed to support sample rotation and translations with increased stability. The experiment was performed at the TRR-1/M1 reactor with 1 MW-reactor power. The neutron beam at the 8-inches south beam port of the TRR-1/M1 was evaluated in terms of beam homogeneity and the relationship between the grayscale value and image quality obtained from a CCD camera. The present performance of the neutron imaging system was tested with an ASTM standard sample, called sensitivity indicator. The results are shown in terms of image contrast and sharpness.
Upgrade of pixel sensor telescope for the characterization of ALPIDE sensor
Authors: Kaewjai J , Kobdaj C , Kittimanapun K 
Published: December 2019

Abstract
A Large Ion Collider Experiment (ALICE) is an experiment station at CERN that detects quark-gluon plasma, a state of matter thought to have formed immediately after the big bang. A plan was proposed to upgrade the particle detector in the Inner Tracking System (ITS) of ALICE by 2020. In the upgrade, new silicon sensor technology, the Monolithic Active Pixel Sensor (MAPS), will be used to replace the ITS. The new sensor is called ALICE PIxel DEtector (ALPIDE). This project focused on the characterization of ALPIDE sensors with a new version of a pixel sensor telescope using the 1.2 GeV electron beam at the Synchrotron Light Research Institute Beam Test Facility (SLRI-BTF). Seven ALPIDE sensors were lined up as a stacked sensor to perform a test using the electron beam at SLRI-BTF. The previous version of the telescope could only characterize the middle area of the sensor; however, the new sensor telescope can be used to characterize edges and corners of the sensor. This advantage provides us with a complete view of the detection efficiency in all sections of the ALPIDE sensor. The detection efficiency of the sensor will be investigated and analyzed by EUTelescope software.
Preliminary design and testing of VAWT blade for low wind speed using CFD
Authors: Akkarachaiphant Thanaphat , Chatthong Boonyarit , Tirawanichakul Yutthana 
Published: December 2019

Abstract
This research aims to study and design vertical-axis wind turbine (VAWT) for low wind speed using computational fluid dynamics (CFD) program called ANSYS® Academic Student Release 19.2. The wind turbine type used is of Savonius type with some parts being modified in order to optimize its rotation in the simulation. The simulation setup is to place the turbine in the middle of the wind tunnel, using initial wind speed of 5 m/s. The turbine itself has dimension of 20 cm of height, 10 cm of radius and 0.15 cm of thickness. These simulation data are used to analyses wind flow dynamics, rotational speed of the turbine, tip speed ratio and Reynolds number of this design. It found that the angular velocity is 200 rpm or 20.94 rad/s, tip speed ratio is 0.41 while Reynolds number is in turbulent flow of 6, 798, 002.
TNT photometric reverberation mapping analysis of high-redshift quasars
Authors: Pongsupa G , Sawangwit U , Wannawichian S , Boonmalai M , Yoyponsan R 
Published: December 2019

Abstract
Supermassive black hole (SMBH) mass determination is essential for understanding the galaxy-SMBH co-evolution. Photometric reverberation mapping (PRM) has been proposed as an alternative to the traditional method, spectroscopic reverberation mapping (SRM), which has limitation to only relatively low redshift, z, and bright objects. However, the most common and important sample of high-z active galaxies known as quasar or QSO have its populations peak at around z ≈ 2-3 thus out of reach for the SRM. We carried out a proof-of-concept campaign of quasar PRM using the 2.4-m Thai National Telescope (TNT) between 2015-2018. Such a study is important to inform a future wide-field high-cadence survey such as the Large Synoptic Survey Telescope (LSST). Our main sample contains 10 quasars at redshift z ≈ 0.7-1.2 with rSDSS
= 19.7-20.7 mag, selected from the SDSS data release 10. The processed data and light curves were analysed using the discrete cross-correlation function (DCF). We used Monte Carlo (MC) simulations to model the noise characteristics and non-uniform coverage of our data as well as to verify robustness of the DCF results. Our analyses show a significant detection of lag time between continuum and broad-line emission bands of the quasar SDSS J081506.93+254124.7 (z = 1.18, rSDSS
= 20.5 mag). The estimated broad line region (BLR) distance is 125±20 light-day which equate to the estimated SMBH mass of (4.3±2.0)×108
M
#x2299;.
The geometric effects of one-dimensional magnetocaloric beds to the efficiency of an active magnetic regenerator: A numerical study
Authors: Yaemphutchong S , Tulyaprawat J , Techapiesancharoenkij R , Hanlumyuang Y 
Published: December 2019

Abstract
Active magnetic regenerators (AMR) are one of prominent alternative refrigeration cycles with a potential to replace conventional refrigerators based on compressed vaper-liquid systems. The magnetocaloric effect of the magnetic bedding solid is at the center of the AMR operation. This work focuses on the numerical investigation of the AMR performances based on the particular designs of multi-layered magnetocaloric beds of 10 layers with the total lengths of 50 mm and 80 mm. The numerical method was based on solving a set of relevant partial differential equations with an interpolating scheme to incorporate the entropic effects of the magnetocaloric beds. Key performance parameters of the two designs were compared against one another. It was found that the choice of 80 mm total bed length yielded only slightly higher performances which implies minuscule economical return in changing the design bed length from 50 mm to 80 mm. The developed numerical scheme allows for the further study of influence of fluid volume flow rate, operating frequency, and utilization to the AMR performance.
The computational study of heat conduction in laboratory using Crank-Nicolson finite difference method
Authors: Saengpayab Y , Kallyalert Y , Pratummasoot N 
Published: December 2019

Abstract
The main propose of this research is to study the heat conduction of an aluminium metal bar in an undergraduate thermodynamics laboratory by using the Crank-Nicolson scheme of finite difference method. Heat conduction was simulated to find the thermal conductivity and was compared with the data obtained from the experiment and theory. In the performed boundary and initial conditions, it was found that the predicted thermal conductivity from the simulation was in agreement with those from the theory, however, it was slightly different from the experiment. These results can be used to improve method to find the thermal conductivity in the laboratory more accurately in the laboratory. Besides, these computational approaches can be an optional teaching method for studying thermal conduction for undergraduates, especially for a laboratory that has limited instruments.
Worksheet analysis for revealing students’ understanding of simple DC circuits
Authors: Kalaya T , Nopparatjamjomras S , Chitaree R , Nopparatjamjomras T R 
Published: December 2019

Abstract
Worksheets are the guideline for students to learn as they can write their own idea, notes, questions, and understandings within the worksheet. Therefore, it is easy to investigate students’ understandings about the topics. In this study, researchers aimed to elicit 70 Thai high school students’ correct understanding and misconceptions of simple DC circuits from their responses on the worksheet. The participants came from 2 schools and attended the simple DC circuits activity. Participants were asked to setup the 3 resistors series and parallel circuits then write down their response to these questions: 1) Which resistor will be burnt first? 2) Sorting amount of the current passing to each resistor and 3) Sorting amount of the potential difference across each resistor. By analysing students’ responses on the worksheet, 3 common misconceptions as 1) Clashing current misconception 2) Stored up and used up current misconception and 3) Closer circuit misconception were found.
Analysis of oedometer and rowe cell consolidation compared to experimental testing
Authors: Zhafirah A , Somantri A K , Permana S 
Published: December 2019

Abstract
Consolidation settlement in clay soils can be predicted by analyzing the consolidation parameters. Consolidation parameters were obtained from the results of a laboratory consolidation test using an oedometer and rowe cell. The rowe cell can measure pore water pressure, soil saturation, and back pressure as a simulation of field condition while the Oedometer cannot. However, there are significant differences between the results of the analysis with the consolidation settlement occurred in the field caused by drainage conditions, the micro characteristics of the soil structure, and the thickness of the soil layer. Therefore, it is necessary to validate the results of settlement in oedometer and rowe cell consolidation analysis with the value of settlement of experimental results. The method used is a laboratory consolidation test using an oedometer and rowe cell as well as a laboratory-scale experimental consolidation test. The results obtained 79% of differences between experimental and oedometer, while rowe cell had a difference of 37% from experimental. Based on this, analysis using rowe cell consolidation parameters can predict a settlement in consolidation in the field more accurately than oedometer, because it has a smaller difference in value.
The water availability effectiveness in weirs
Authors: Permana S , Johari G J , Yogaswara D , Walujodjati E 
Published: December 2019

Abstract
The Availability of water for irrigation is critical in the sustainability of crops. One of the primary water sources to maintain and even increase yields is the river. Mount Galunggung has many sources of water. Cibanjaran River is one of the rivers that originate on Galunggung mountain used to flood an area of 595 ha of rice fields. At present, the river has undergone silting due to sand mining activities next to the weir. The purpose of this study is to determine the effectiveness of the available discharges in the river in meeting the needs of the rice fields that are due to river sedimentation. Available data processing methods are used to analyze the availability and needs of water. Planting plan in November, water requirements in the rice fields are 1.5 lt/sec/ha. The available discharge is not able to meet the needs of 595 ha of rice fields. River sedimentation due to sand mining upstream affects the availability of water because a lot of water overflows above the spillway so that it cannot be utilized. The use of a group system and scheduling water supply provides the right solution in the distribution of water.
Factors affecting competitiveness small contractors in construction industry
Authors: Johari G J , Walujodjati E , Mulyana S , Permana S 
Published: December 2019

Abstract
The construction industry is a very promising business area in terms of infrastructure development and financial benefits. Many factors influence the competitiveness of small contractors in the construction industry. This study aims to identify what factors influence competitiveness and identify what are the dominant factors that affect the competitiveness of small contractors in the construction industry in West Java. The author uses descriptive and explanatory research methods which are then processed by statistical methods using validation tests, reliability tests, and factor analysis. The results of this study indicate that all variables are valid and pass the reliability test. Of the 9 factors studied, it has a significant influence on the competitiveness of small contractors in the construction industry in West Java. There is 1 dominant factor that influences the competitiveness of small contractors in the construction industry in West Java, namely project management factors. These indicators are; Location management, Cost management, Quality management, Time management, Contract management, Problem solving expertise, Risk management, Logistics and supply chain management, Effectiveness in coordination with subcontractors, Effectiveness in site safety management, Knowledge of local construction law, Number of major accidents in The last 3 years, and the contract ratio successfully committed. for project implementation, Coordination of all activities and labor involved.