bluuebunny/crossref_metadata_2025 huggingface dataset:
Algorithm and computer program to determine metric dimension of graph
Authors: Muhammad F , Susilowati L
Published: May 2020

Let G be a simple, connected and undirected graph with vertex set V(G) and a subset W = {w
1, w
2, w
3, … wt
} ⊆ V(G) is order set. A representation of vertex v ∈ V(G) with respect to W is an ordered t − tuple r(v|W) = (d(v, w
1), d(v, w
2), d(v, w
3), …, d(v, wt
)) where d(v, wi
) is the distance between vertices v and wi
. The set W is called a resolving set for G if every vertex of G has a distinct representation with respect to W. A resolving set containing a minimum number of vertices is called basis for G. The metric dimension of G denoted as dim (G), is the number of vertices in a basis of G. In our study, we construct the algorithm to determine the basis and dimension of graph G. The algorithm is checking all possibility combination of vertex set such that the vertex set has the minimal cardinality of resolving set. Furthermore we design the computer program to find the basis and dimension of graph.
An Adams type inequality of fractional integral operator on hypergroups
Authors: Sihwaningrum I , Wardayani A , Dasril Y
Published: May 2020

In this paper, an Adams type inequality of fractional integral operator will be presented on the generalized Morrey spaces over commutative hypergroups. This inequality needs an estimation of the fractional integral operator by the maximal operator. Besides, the almost decreasing of functions and Ahlfors condition of the measure are also involved.
Regular rings and their properties
Authors: Wardayani A , Kharismawati I , Sihwaningrum I
Published: May 2020

In this paper, we present some properties of regular rings. The properties are developed from the properties of regular semigroups. The properties of regular rings here are especially related to the center of the rings, division rings, Boolean rings, commutative rings, and subrings. The division and Boolean rings must be regular rings. The center of a regular ring is also a regular ring. A regular ring has to be a commutative ring. In addition, a subring of a regular ring is also a regular ring.
Removal of rhodamine b using 4-hydroxy-3-methoxyphenylcalix[4]resorcinarene
Authors: Handayani S N , Irmanto  , Indriyani N N
Published: May 2020

Rhodamine B is one of the dyes that is widely used in the textile industry. However, the rhodamine B waste produced is dangerous for the environment. So, it must be treated propely. Adsorption is a simple method that can be used in waste water treatmen. In the present study, the adsorbent used is 4-hydroxy-3-methoxyphenylcalix[4]resorcinarene (CHMFKR) which is synthesis from vanillin and resorcinol. The yield of product was synthesis is 85.707%. The removal of rhodamine B by calix[4]resorcinarene was investigated in the present study. Adsorption studies were performed by batch experiments. The effect of contact time, pH, initial dye concentration was explored. The optimum conditions at contac time 75 minutes and pH 7. The adsorption kinetics of rhodamine B using calix[4]resorcinarene followed second pseudo order. The isotherm study showed that adsorption rhodamine B using 4-hydroxy-3-methoxycalix[4]resorcinarene followed Freundlich isotherm with adsorption energy of -33598.02 J/mol, kf value 1.29 x 10−6 L/mol and qmaks 6.157 mg/g.
Triterpenoid and Steroid from the Rind of Chisocheton macrophyllus (Meliaceae)
Authors: Sari V M , Nurlelasari  , Harneti D , maharani R , Indrayati N , Azmi M N , Supratman U
Published: May 2020

Terpenoids form numerous and structurally diverse family of secondary metabolites derived from C5 isoprene units joined in a head-to-tail fashion. Among the terpenoids, triterpenoids emerge as a unique and large group of phytochemicals. There is secondary metabolites steroid, which is modified triterpenoids containing tetracyclic ring system but losing three methyl at C-4 and C-14. Triterpenoids and steroids can be obtained in the family Meliaceae. The Chisocheton genus which is part of the Meliaceae family is known for secondary metabolites, such as terpenoids, phenolics, and steroids. The purpose of this research is to isolate and to elucidate triterpenoids and steroid compounds from rind of Chisocheton macrophyllus. Stigmastane-type steroid Stigmast-22-en-3β-ol (1) and pentacyclic triterpenoid moronic acid (2), were isolated from the n-hexane extract of the rind of C. macrophyllus using column chromatography. The chemical structures of compounds 1-2, were identified on the basis of spectroscopic evidence and by comparison with those spectra previously.
The pH dependence of Ag3PO4 synthesis on visible light photocatalytic activities
Authors: Futihah I , Riapanitra A , Yin S , Sulaeman U
Published: May 2020

The Ag3PO4 morphology modification may affect the photocatalytic activity due to changing the surface energy. It may be designed by coprecipitation under different pH solutions. The pH dependence of Ag3PO4 synthesis on photocatalytic reactivities was investigated. The Ag3PO4 photocatalysts were synthesized in water-ethanol mixture solution under variation of pH from 3 to 11. The products were characterized using XRD, DRS, SEM, and BET specific surface area. Photocatalytic activities were studied using the degradation of RhB under visible light irradiation. The results showed that the mixed morphologies of the sphere, cube, tetrahedron, and irregular were formed. The highest activity of Ag3PO4 was obtained from the synthesis at a pH of 11, which may be caused by a smaller particle size and a higher amount of tetrahedron.
Effect of ultraviolet and visible lights on degradation of congo red dye using Fe2+/H2O2
Authors: Tama J , Riyani K , Setyaningtyas T
Published: May 2020

Congo Red is one of the reactive dyes that often used in the textile industry. The presence of Congo red dyes in the environment can damage various living species because of high toxicity. One alternative method to degrade the Congo red is Fenton Reagent. Fenton reagent is defined as a mixture of H2O2 and Fe2+. The Fenton reagent produces a hydroxyl radical (HO •), which degrades Congo red dyes under light irradiation; this reaction is called the Photo-Fenton reaction. The purpose of this research is to determine the effect of visible and ultraviolet irradiation on Congo Red degradation using the Fe2+/H2O2. The results showed that the optimum condition of degradation achieved at 350 ppm, 400 ppm for H2O2 and FeSO4.7H2O concentration, respectively, and pH 3. The kinetics analysis showed that the Congo Red degradation followed the pseudo-first-order kinetics, and Congo Red degradation under UV light showed the highest rate constant.
Introducing Iron Analysis with Smartphone Camera for High School Students
Authors: Fatoni A , Zusfahair  , Anggraeni M D
Published: May 2020

Chemical analysis studies how to analyze both qualitative and quantitative materials. Analysis based on color differences, also known as colorimetry. The basic theory of the analysis is generally given to high school and university students. However, only a few schools practice the theory because of the limitations of expensive instruments. The limitations of expensive instruments have stimulated research to utilize simple daily life devices as alternative of analytical instruments, such as cameras on smartphones, pocket cameras, professional cameras (DSLRs) and scanners. This work reported the use of a smartphone camera (handphone) as a colorimetric iron analysis tool by comparing the color of the sample solution with the standard iron solution. The study starts with the explanation of basic theory of spectrometry and colorimetry, followed by experiments using smartphone cameras for iron analysis using an analysis kit containing o-phenanthroline. The results showed an increase in students and teachers high school knowledge.
Quantitative Structure Activity Relationship Analysis of 1,3,4-Thiadiazole Derivatives as Anti-Inflamatory using Parameterized Model 3 Method
Authors: Iswanto Ponco , Permata Saputri Maylani , Eva Vaulina Y.D. , Paramita Sari
Published: May 2020

Quantitative Relationship Structure and Activity Relationship (QSAR) studies conducted on the anti-inflammatory activity of a series of 1,3,4-thiadiazole derivatives which aim to obtain an equation to predict the value of the anti-inflammatory activity of. As research material was experimental biological activity data of 28 1,3,4-thiadiazole derivatives which were divided into 25 fitting compounds and 3 test compounds. QSAR analysis was carried out based on multiple linear regression calculations of fitting compounds by plotting log BA as the dependent variable and the independent variable was the net charge of carbon and nitrogen atoms bound to the dressing group, dipole moment (µ), HOMO-LUMO, Log P, molecular weight, polarizability, hydration energy, and van der waals volume. The value of descriptors was obtained from calculations using the PM3 semi-empirical quantum mechanical method. The result of QSAR equation was:

Log BA = 68.112 − 8.482 (qC1) + 14.764 (qC15) + 1.071 (Log P) − 0.018 (MW) − 0.484 (µ) − 4.427E-5 (Polarizability) − 0.561 (E. Hydration) + 7.843 (HOMO) − 1.489 (LUMO)

n = 28, r = 0.861, SE = 0.170098, Fcalculate / Ftable = 2.02116, PRESS = 1.9665
Study of Thin Film Cu Nanowire and Reduced Graphene Oxide as A Gas Sensor
Authors: Wijayanti Noviana Candra , Cahyaningrum Ratih Dwi , Harsojo
Published: May 2020

Reduced graphene oxide (RGO) has potential as various gas sensors. However, the sensitivity depends on the size of layers and the number of exfoliated planes. We fabricated a gas sensor based on the RGO on top of silver electrode and RGO on top of copper nanowires put on similar electrodes. The graphene oxide (GO) was synthesised using Hummer’s method. It was made into RGO using hydrazine as a reduction media. We constructed the gas sensor on top of silver electrodes. The distance between electrodes was 0.5 mm. The RGO sensor was tested to detect several gases in the resistive mode. We also compared the performance RGO sensor on top of Cu nanowires (CuNWs) with the RGO without the CuNWs. The result indicated that the response was in the order of percent when exposed to different concentrations in the range of 100 ppm and 500 ppm. However, the RGO sensor put on directly on Ag electrodes are more sensitive compared to RGO CuNW-Ag sensor.
Estimation of Ideal Configuration and Dimension of Pico Hydropower using Euler-Lagrange Equation and Runge-Kutta Method
Authors: Aminuddin J. , Nurhayati  , Widiyani A. , Razi P. , Wihantoro  , Aziz A.N. , Abdullatif R.F. , Arifin A.
Published: May 2020

Pico hydropower is a type of hydropower that can produce electric power under or equal to 5000 Watt. Consisting of one turbine to rotate one generator, it has been used in remote areas to provide for electricity supply. Although the system serves quite well, sometimes the necessity for electricity supply is larger than the system can supply. The solution would be to build two pico hydropower systems. However, the cost of such a solution will also double. In addition to that, the water source and landscape may not sustain more than one pico hydropower. An alternative solution that is being proposed to resolve the problem is by using one turbine to rotate two electric generators in a unity pico hydropower system. The objective of the study concerning the proposed solution is to obtain a configuration and dimension of the energy converter. They are sought by determining the equation of motion for energy converter which is configured in several wheels. The equation of motion, which is in differential form, is obtained using the Euler-Lagrange procedure in classical mechanics. Both configuration and dimension of energy converter are solved using numerical methods. The numerical method used in this study is the fourth-order of the Runge-Kutta method for analyzing some physical parameters i.e.: angular velocity of the energy converter, friction coefficient, driving force, radius and inertia of the wheels. By employing varying numbers in the computational process using the fourth-order of the Runge-Kutta method in Matlab, we seek that the pico hydropower system with ideal configuration and dimension of energy converter based on the radius of the wheels are configured as r
1> r
3>r
2>r
4>r
5=r
6. The configuration yield an optimum rotation of the coupled wheels (r
5 and r
6) as a representation of the electric generator’s axis although the thrust is assumed lower. The design expected to be a solution for optimizing a pico hydropower, especially in remote areas with lower water flow.
Designing of Muffler Part for Car Exhaust System with Low Emission and Noise using Conjugate Gradient Method
Authors: Aminuddin J. , Wihantoro  , Bilalodin  , Sunardi  , Rauf N.
Published: May 2020

The exhaust is an important spare part of the car for reducing noise and emission. The Noise is an unexpected sound from the roar of the engine that caused a hearing problem. The emission is originated from the combustion of an engine that causes air pollution. In this study, we enhance an exhaust performance for decreasing noise and emission by optimizing of the muffler part. Through the conjugate gradient method, we estimate an ideal dimension of the muffler part for circulating thermal energy at around 26 kcal/mole for 13.39 seconds in the closed system. From the results of the conjugate gradient estimation, we develop the muffler plus a re-heater with 58 and 14 cm of length and diameter, respectively. Furthermore, the muffler’s performance is evaluated by doing a measurement of both noise and emission. The measurements are conducted by comparing the muffler without and with re-heater. From the measurement process of sound intensity level, we seek that the noise is decreased by approximately 3.79 and 3.00 % in the lower and faster rotation of the engine, respectively. Besides, the test result shows that utilizing re-heater can reduce of CO, CO2, and HC of 0.35, 14.6, and 76.29 % compare to the muffler without re-heater. The results indicate that the muffler with re-heater designed in this study is effective in reducing noise and emission from the roar and combustion of the engine, respectively.
Cimandiri Fault Identification Using Earthquake Tomography Double-Difference Method
Authors: Simanjorang R G , Rosid M S , Sembiring A S , Daryono  , Heryandoko N
Published: May 2020

Cimandiri Fault is one of major faults in West Java, which has a considerable potential hazard to the surrounding populated area. Therefore, it’s important to have a better understanding about the fault in order to improve disaster mitigation effort in Indonesia. This study is done to identify the Cimandiri Fault based on tomography earthquake data. The recorded data of 290 events were acquired from 15 BMKG seismograph stations located in the vicinity of study area. All events have a total of 2,895 phases consisted of 2,072 P-wave phases and 823 S-wave phases. The method used in this study to produce images beneath the surface of Western Java is double-difference travel time seismic tomography. Inversions were performed using the TomoDD algorithm to image seismic velocity models with horizontal variations from Banten Province and West Java. The final results of this study show the existence of Cimandiri Fault located in the southern part of West Java and extends with direction of North East-South West through Pelabuhan Ratu until it reaches the ocean in the south of Banten.
Tomato Harvesting Arm Robot Manipulator; a Pilot Project
Authors: Oktarina Yurni , Dewi Tresna , Risma Pola , Nawawi Muhammad
Published: May 2020

Promoting digital farming might be the answer for current challenges in the agriculture industry by employing a robot to provide continuous information of its deployed area and gives the right analysis in many aspects of farming. This paper discusses the pilot project of employing robot as a harvesting robot. The fruit to be picked is red and green tomatoes. The objective of this study is to set the initial project in creating a series of robots applied in agricultural to realize the idea of digital farming. The novelty of this study is that this method is simple, and image processing is kept simple to accommodate processors limited computation resources. The robot designed is customized according to the size of the tomato tree and tomato. The tomato location is indicated by a circle resulted from the image processing and divided into left, right, and middle position in the image plane. The image plane resolution in this study is 320 × 180 pixels. Ifx= 15 pixels andy= 42 pixels, then the output angle of servo motor on the based is 1150, servo motor joint1 is 900, and servo motor joint2 is 1000. The arm robot moves to the left and harvests the tomato. The average time for harvesting red tomato is 4.932 s, and green tomato is 5.276 s. The required time for the robot from detecting red tomato and return to standby position is 9.676 s, and 10.586 s for the green tomatoes. This time difference is due to robot distance to tomato and not the color of the tomato. The experiment shows that the robot successfully harvests the tomatoes in the setting given in this study, and proves the effectiveness of this robot design as an agriculture robot.
Odd-even harmonic generation from oriented CO and NO molecules within strong-field approximation
Authors: Le Cam-Tu , Phan Ngoc-Loan
Published: May 2020

Recently, the pure-even high-order harmonic generation (HHG) has theoretically found by the ab initio methods for CO molecules interacting with an intense laser. An examination of this phenomenon using the analytical approach such as the Lewenstein model, and for another polar molecular with other symmetry is needed. In this study, we theoretically investigate the odd-even harmonic generation from the CO and NO molecules in the linearly polarized laser field by using the Lewenstein model. Firstly, we confirm entirely the pure-odd and pure-even emission from CO whose molecular axis is perpendicular to the polarization direction of the laser. Secondly, we show that the odd-even behavior of the HHG spectra from NO is similar to that from the CO molecule. The HOMO’s symmetricity of the linear molecule does not change the odd-even property of the HHG spectra.
Sensitivity of gas-phase electron diffraction images to the molecular potential parameters
Authors: Phan Ngoc-Loan , Nguyen Hien T
Published: May 2020

The gas-phase electron diffraction (GED) is a conventional method to extract the geometrical structure and the vibration parameters of molecules. In practice, the mean vibration amplitude is retrieved successfully, while the anharmonicity parameter is usually fixed by a relation with the former. To explicit the reason, we examine the sensitivity of the molecular scattering curve (sM(s)) of N2 molecule to the vibration parameters. The results show that the sM(s) curve is sensitive to the mean vibration amplitude but considerably stable with the changing of the anharmonic parameter even at a high temperature. Besides, many recent studies also focus on the investigation of the laser-induced electron diffraction (LIED) since its high temporal and spatial resolution. However, it is hard to extract the vibration parameters from the LIED data because of the shortage of the analytical form of sM(s) caused by the complicated physical process. So we propose to directly reconstruct the molecular potential instead of extracting the vibration parameters from the LIED. The preliminary purpose is to test the sensitivity of the sM(s) curve to the potential parameters of the Morse potential of N2 considering the nuclear vibration for GED. We demonstrate that the sM(s) curve is sensitive to the change of the potential parameters; thus, the molecular potential can be reconstructed from the GED. This statement is an essential precondition for further investigation of not only the influence of the vibrational effect on the probing of the molecular dissociation but also the reconstruction of the molecular potential from the LIED data.
Mechanisms of nonsequential double ionization process of argon by near-single cycle laser pulse
Authors: Truong Thu D H , Pham Vinh N T
Published: May 2020

In this paper, the near-single cycle laser pulse is used to trigger the nonsequential double ionization process of argon atom due to its ability to eliminate the contamination from secondary recollisions. The mechanisms and distributions of recollision-ionization channels are thoroughly investigated for two representative laser intensities which provide returning energies well below and above the recollision-ionization threshold of argon. The results indicate that recollision-induced excitation with subsequent ionization and direct ionization mechanisms are dominant for low and high intensity of laser, respectively. In addition, the extraction of cross-shaped structure in the correlated two-electron momentum distribution is presented along with the investigation to understand the origin of this interesting structure.
Electrically controlled magnetism in iron thin film
Authors: Van Quang Tran
Published: May 2020

The coupling of ferroelectric and ferromagnetic order parameters in low dimension materials has been of great interest due to the potential spintronic applications. In this report, by employing first-principles density-function-theory calculation without including spin-orbital coupling, it is demonstrated that the magnetization of iron thin film increases in proportion to the external electric field and it prefers to be perpendicular to the film plane. This intriguing property stems from the spin-dependent screening of the electric field which leads to a spin imbalance of the excess surface charge. The result is in agreement with previous publications. We suggest that the electrically controlled magnetism might be used in advanced magnetic and electronic devices.
Biexciton in 2D parabolic quantum dot in magnetic fields
Authors: Hong Quang Nguyen , Anh Dung Tran
Published: May 2020

We theoretically study biexciton, exciton and charged excitons confined in 2D parabolic quantum dots in a magnetic field by using an unrestricted Hatree-Fork method. The energy and binding energy of exciton and biexciton are presented as a function of magnetic field which show their increase with increasing magnetic field, although small. Our results for the case of strong confinement in InAs/GaAs self-assembled quantum dots show that, while the binding energies of both exciton and negatively charged exciton are positive, the binding energies of the biexciton and positively charged exciton are negative indicating that biexcitons in this system are antibinding.
Temperature-dependent transport properties of two-dimensional hole gas in Ge channel modulation-doped square quantum wells
Authors: Thi Hai Tran , Thi Dung Nguyen , Thi Thao Nguyen
Published: May 2020

We present a theoretical study of the transport properties of two-dimensional hole gas (2DHG) in Ge channel modulation-doped square quantum wells, with very high room-temperature drift mobilities. Within the variational approach, we obtain analytic expressions for the carrier distribution, and autocorrelation functions for various scattering mechanisms. The results were used to determine the hole mobility where only the relevant scattering processes, namely acoustic phonons (Deformation potential and Piezoelectric coupling), ionized impurity, surface roughness were considered. The partials and total mobility dependences on temperature were found. It is shown that acoustic phonon and surface roughness scattering are the dominant mechanism. The interpretation of these results is carried out and the scattering mechanisms limiting the 2DHG mobility in Ge quantum wells of SiGe heterostructure are discussed.
The quantum Ettingshausen effect in parabolic quantum wells with in-plane magnetic field in the presence of laser radiation under the influence of confined optical phonon
Authors: Nguyen Thi Lam Quynh , Nguyen Thu Huong , Nguyen Ba Duc , Nguyen Quang Bau
Published: May 2020

The quantum Etttingshausen e˙ect in a parabolic quantum well subjected to a constant electric field, magnetic field in the presence of laser radiation is studied by using the quantum kinetic equation method. The analytic expressions for conductivity tensors and dynamic tensors as well as the Ettingshausen coe˚cient (EC) are obtained in the case of the confined electron-confined optical phonon (COP) scattering. The EC depends on specific quantities for external field (such as magnetic field, amplitude and frequency of laser radiation), temperature of the system and quantum well length, especially quantum number m-characterizing the confinement of optical phonon (OP). When m is set to zero, we get the results corresponding to the case of unconfined OP. The analytic results are numerically evaluated and graphed for GaAs/AlGaAs parabolic quantum well. When examining the e˙ect of temperature, the EC has greater values due to the COP. Meanwhile, when quantum well length and amplitude of the laser radiation (LR) increase, the EC has greater values without the confinement of OP. Because of the approach of system to bulk semiconductor structure when the quantum well length approaches micrometer-size, the EC reaches constant. The quantum number m leads to the change of resonance peaks position within the change of the magnetic field and the frequency of LR. In addition, the EC exerts non-linear dependence on the amplitude the LR. All results indicated that the COP a˙ects not only qualitatively but also the transformation rules of the EC. It provides new insights and contributes to the orientation of research into quantum e˙ects in low-dimensional semiconductor systems (LDS).
Classical interpretation of dynamics of ultracold atoms in the titled optical lattice
Authors: Pham Vinh N T , Ho Huy H
Published: May 2020

In this paper, we study the dynamics of ultracold 87Rb under the influence of tilted optical lattice via Bloch oscillation in the single-band regime. By simulating the intraband dynamics of wavepacket in position and momentum spaces, the dependences of amplitude and period of the oscillation on tilted coefficient and lattice height are shown and compared with classical theory under tight-binding approximation. We also verify the limit of the single-band approximation where the Landau-Zener transition is neglected.
Thermal expansion for ordered Cu3Au alloy at higher temperature and under pressure.
Authors: Duy Tan Pham , Dinh Tam Pham , Duc Tinh Bui
Published: May 2020

The thermodynamic properties of alloys are studied using the statistical moment method (SMM), which allows us to take into account the anharmonicity of the thermal lattice vibration. Within the forth-order moment approximation, the free energy, equation of state and lattice spacing of the binary ordered alloys with cubic structure are given explicitly in terms of the effective pair potentials and the second - and fourth - order vibrational coefficients. Applying to ordered Cu
3
Au alloy, we determine these properties at higher temperature and under pressure in simple analytic form. Numerical results for the lattice parameter, pressure-volume dependence of this alloy in different temperatures and pressures are in good agreement with experiments, better than other calculations.
Protein escape at an atomistic model of the ribosomal exit tunnel
Authors: Thuy Bui Phuong , Xuan Hoang Trinh
Published: May 2020

We study the post-translational escape of nascent proteins at the ribosomal exit tunnel by using the Go-like model for proteins and a real shape atomistic tunnel built on the protein data bank (PDB) structure of a ribosome of Haloarcula marismortui. The full translation and escape processes of the immunoglobulin binding B1 domain of protein G (GB1) at the tunnel were simulated by using Langevin dynamics. We show that at the simulation temperature corresponding to a physiological temperature, the escape time follows quite well the one-dimensional diffusion model proposed in our earlier works. The relationship between folding and escape obtained for the atomistic tunnel is similar to those obtained previously for the cylinder tunnel.
Different space characteristics of air temperature variation in North Sumatra Indonesia
Authors: Prasetya T A E , Munawar  , Chesoh S , Lim A , McNeil D R
Published: May 2020

Land Surface Temperature (LST) can be used as an indicator of measuring temperature change in the regions. The changing variation can be produced or affected by some factors such as elevation, land cover products, and Normalized Difference Vegetation Index (NDVI). This study aimed to investigate LST variation based on elevation, land cover products, and NDVI in the North Sumatra area, Indonesia. Land products satellite data between 2000 and 2018 were downloaded from the moderate resolution imaging spectroradiometer (MODIS) website. Multiple linear regression was used to find the patterns of LST variation. The highest LST variation was found in Evergreen Broadleaf (EB) forest and urban area with the average change 0.4 and 0.5 °C/decade and the lowest was found in water surface area with the average change more than -1 °C/decade. The overall mean of LST changing was -0.1 °C/decade with r-square 31.4%. There was a unique LST variation in EB forest land cover when the elevation increased, the LST also increased from -0.4 to 0.5 °C/decade. The same condition also appears in Savannas and cropland/natural vegetation mosaic (Crop. Mos.). In conclusion, the changing of LST in North Sumatra was affected by elevation, land cover products, and NDVI.
Techno-economic analysis of satellite implementation as a broadband internet provider in Indonesia
Authors: Mubarak R , Budiyanto S , Wulandari P
Published: May 2020

Indonesia is an archipelago that consisting of a group of islands from Sabang to Marauke. To be able to communicate each other, it needs a telecommunications network that can load all regions of Indonesia, without exception. The use of satellites as a means of telecommunications is very suitable to be applied in Indonesia. Because by using satellites, operators can provide internet services to rural areas that cannot access internet services by terrestrial networks. This is what causes businesses in this field is very promising. However, this business is not an expensive business because it requires very large costs in planning until operating. Therefore, it takes a research that shows the feasibility of this business for people to investment. In this paper shows that, NPV value during the active period of the satellite was USD 555,804,583 with an IRR value of 7% with PBP 5 years 8 months. Based on these parameters it can be seen that the investment is still classified as feasible to continue.
Readiness analysis of accreditation data: a case study for Indonesian higher education
Authors: Primadewi A , Hanafi M , Sasongko D , Setiawan A , Arumi E R , Sunarni  , Nugroho S , Artha E U
Published: May 2020

Higher Education as Indonesian education products must have a strategy to deal with the 4.0 Industrial Revolution. Accreditation of Higher Education is one of the parameters of higher education success in increasing capacity and competitiveness. Accreditation is a process of evaluating quality towards Higher Education Institutions as a whole to determine institutional commitment. This commitment is related to institutional capacity and educational effectiveness based on accreditation standards established by BAN-PT. This research takes the Zachman framework as an Enterprise Architecture because it can position business functions, application functions, and data entities simultaneously.
Buckling analyses of carbon nanotube reinforced functionally graded composite cylindrical panels
Authors: Huang Zhong-Tong , Lin Bin , Zhang Shun-Qi , Gao Ying-Shan , Lin Lv-Sheng
Published: May 2020

This paper investigates the buckling analyses of carbon nanotube (CNT) reinforced composite cylindrical panels via a geometrically nonlinear finite element model with large rotations based on the first-order shear deformation (FOSD) hypothesis. Fully geometrically nonlinear strain-displacement relations and large rotation of shells are considered in the model. First, the proposed model is validated by a frequency analysis of a simply supported CNT reinforced composite cylindrical panel from an existing reference. Then, the model is applied to simulate the behaviors of carbon nanotube reinforced functionally graded (CNT-FG) composite cylindrical panels. The effects of curvature ratio, different buckling behaviors and four representative forms of CNT distributions are studied for their material performance comparatively.
Buckling and post-buckling of FRC laminated beams in thermal environment using a generalized higher-order shear deformation zig-zag beam model
Authors: Jin Qiduo , Ren Yiru
Published: May 2020

The thermal buckling and post-buckling of fibre-reinforced composite (FRC) beams are analyzed based on a generalized higher-order shear deformation zig-zag beam theory (RHDZT). The current zig-zag beam model satisfies the stress boundary conditions on the upper and lower surfaces and the reality that the shear strain is discontinuous at the layer interfaces. The material properties of FRCs are assumed to be temperature independent and the in-plane boundary conditions supposed immovable. By using the Hamilton variation principle, the governing equations are established based on the mid-plane of the beam. A two-step perturbation method is employed to obtain the approximate analytical solutions of the critical thermal buckling loads and post-buckling behaviors with clamped-clamped boundary conditions. The critical buckling results based on the zig-zag model and its degenerate equivalent single-layer models are compared and verified with those in the literatures. The post-buckling results of the FRC beams with different slenderness ratios, elastic modulus ratios and ply angles are investigated. Numerical results show the remarkable accuracy of the current model and also demonstrate the significant roles the above-mentioned effects play in the buckling and post-buckling problem of FRC laminated beams.
Impact characteristics of railway bridge with double-block supported track considering carriage oscillation loads
Authors: Wang Yuchen , Sun Zhi
Published: May 2020

In this study, the impact characteristics of a typical railway bridge with ballastless double-block supported track under moving train considering carriage oscillation load is investigated. The train load is modelled as a constant force superimposed with a harmonic force whose frequency is the heaving oscillation frequency of the carriage. The bridge-track system is discretized and modelled using the double-beam elements connected using the elastic springs and viscous dampers. Numerical computations are conducted to investigate the bending moment impact characteristics of the supporting bridge considering the variations of moving speed and oscillating frequency of the moving load. The result shows that the harmonic loads due to the carriage heaving oscillation will induce some important bending moment impact amplification and peak response offset for the studied bridge in operation.
Vibration characteristics and stability of a moving membrane with variable speed subjected to follower force
Authors: Wu Jimei , Qing Jiajuan , Shao Mingyue , Wang Yan , Li Ni , Ruan Miao , Liu Dingqiang
Published: May 2020

In this paper, the vibration characteristics and stability of a moving membrane with variable speed subjected to follower force are studied. The vibration differential equation of the moving membrane is deduced by the D’Alembert principle. The intermediate variables of the differential equation are discretized by the Differential Quadrature Method, and the state equation with periodic coefficients is obtained.The state equation is solved by the implicit Runge-Kutta method. According to the Floquet theory, the dynamic stability region and instability region of the membrane are obtained, and the influence of the tension ratio, aspect ratio, average velocity and the follower force on the unstable region of the moving membrane are analyzed. This result provides theoretical guidance and basis for the design, manufacture and stability of the printing press.
Analysis on Existence of New Stable Attitude of Spatial Flexible Damping Beam
Authors: Xu Mengbo , Hu Weipeng
Published: May 2020

In my previous works, the attitude stability of the spatial flexible damping beam was investigated employing the structure-preserving method and a new stable attitude was found when the non-sphere perturbation effects were considered. But the new stable attitude state is lack of theoretical explanation. In this paper, the existence of the new stable attitude of the spatial flexible damping beam with the non-sphere perturbation will be discussed referring to the coupling dynamic model describing the couple motion between the orbit motion, the attitude evolution and the transverse vibration of the spatial flexible damping beam. The conclusions obtained in this paper illustrate the existence of the new stable attitude of the spatial flexible damping beam and verifies the numerical results presented in my previous job.
Analysis and research on wheel steering motion of four-wheel locomotive
Authors: Zhao Jie , Wang Yan
Published: May 2020

Main purpose of this paper is to analyze the kinematics characteristics of four-wheeled vehicles. Based on the kinematic discrete recursion formula and the kinematic relationship between the wheel and the fuselage, the kinematic discrete recursive model of the system is established, and the theoretical formulas of the front wheel steering and four wheel steering vehicle models are derived respectively. At the same time, Simulink was used in Matlab to simulate the driving process of the four-wheeled vehicle, and the steering angle of the wheel relative to the vehicle body and the trajectory of the front and rear wheels during the driving of the four-wheeled vehicle were obtained. The derived model data is used to simulate the satellite positioning wheel trajectory, and the variation law of the wheel steering angle during the driving process of the four-wheeled vehicle is obtained. The correctness of the analysis process and method is verified by theoretical derivation and numerical simulation, which provides a theoretical basis for the study of kinematics characteristics of smart cars in the future.
Theoretical studies on biological additives preparation in a blender with a sinusoidal blade paddle mixer
Authors: Fomina M V , Chupshev A V , Teryushkov V P , Konovalov V V , Mishanin A
Published: May 2020

The purpose of the research is to establish the relationship of the geometric parameters of the sinusoidal paddles of a mixer with part of the motion indicators of low-altitude radial sectors of bulk material and the possibility of numerical simulation using existing characteristics. The effect of the flat and sinusoidal mixer blades of the blender, in terms of their construction, on the process of moving layers of the mixed material has been theoretically studied. The equations obtained allow us to state that, due to the difference in the geometry of the blades' surface, when the blades are flat, an inertial shock occurs when the blade contacts the material sector due to its sharp acceleration to the peripheral velocity. With sinusoidal blades, acceleration to a specified velocity is stretched in time, taking into account the amplitude of the sinusoid, reducing the energy cost of the friction of material layers. The obtained equations allow us to identify the relationship and numerically simulate the change in the main indicators of the material position in the blender.
Studying the design and operational parameters of the sieve module of the grain cleaning machine
Authors: Kharitonov M K , Gievsky A M , Orobinsky V I , Chernyshov A V , Baskakov I V
Published: May 2020

The purpose of the study is to improve the efficiency of sieve cleaning by justifying the kinematic mode of operation and a rational scheme for the distribution of sieves in mills, depending on their purpose. Raw combine heaps of winter wheat of the “Alaya Zarya” variety and barley of the “Priazovsky 9” variety were used as grain material. The conducted research allows us to justify the angles of inclination of the ear sieves, which should be located in the upper tier with an angle of inclination to the horizon of 7° and be equipped with lattice cloths with round holes (a diameter of 7.5 or 8.0 mm). The frequency of oscillation of the sieve mill must be selected in the range of 340-370 min-1, which provides the maximum completeness of the selection of feed fractions by sorting sieves. In one tier in length, preference should be given to the placement of three lattice cloths.
Optimization of parameters of ecological-meliorative product for preseed treatment of soil
Authors: Tarasenko B F , Oskin S V , Tsybulevskiy V V , Karpenko V D , Rudnev S G
Published: May 2020

It has been established that the imbalance of soil processes caused by insufficient intake of organic matter into the soil causes its degradation, decreased fertility, and humus content. There is a problem of ensuring environmental safety. It was also established that the development of new or the improvement of existing structural and technological solutions for tillage is of particular practical interest. Pre-sowing cultivation of the soil is a thorough closure and preservation of moisture through the creation of the upper mulched surface, the destruction of weeds and the creation of favorable conditions for seed germination at a biologically optimal depth of planting. For the steppe zone of the North Caucasus (Krasnodar Territory, Rostov Region and Stavropol Territory), which is the main grain-sowing zone in Russia, research is needed to develop innovative means for pre-sowing treatment that provides the accumulation and preservation of moisture and nutrients, reduces fuel consumption and stable movement of working bodies in soils having different densities. To solve this problem, the hypothesis was put forward at Kuban Agrarian University that in order to ensure moisture conservation and reduce energy consumption, stability of movement of the working bodies of the device in soils with different densities is required, while the stand must deviate under the influence of external resistance in three planes. The research was developed and protected by the patent “Device for presowing tillage”. Studies have been carried out to optimize the energy costs of an innovative tool for presowing tillage using experimental design methods that confirm effectiveness.
Influence of the droplet size on the uniformity of the distribution of protective material over the surface of agricultural machinery
Authors: Ushanev A I , Uspenskiy I A , Yukhin I A , Filyushin O V , Podyablonskiy A V
Published: May 2020

A decrease in the diameter of a droplet of a protective coating stream occurs in cases of a decrease in the diameter of the nozzle, an increase in the volumetric flow rate and the lower surface tension coefficient. To study the effect of droplet sizes on the quality of the protective coating, the conditions for obtaining droplets of different diameters were determined. During the experiment, it was found that the most significant parameters were those of the nozzle and the operating pressure of the installation. The change of these parameters caused the change of the size of the material droplets. To do this, replaceable nozzles with various diameters were installed and the supply pressure was also regulated.
Application of specialized software systems for determination of normal and emergency operation modes parameters of power distribution networks
Authors: Yastrebov S S , Os’kin S V , Yarosh V A , Bogatyrev N I , Ivashina A V
Published: May 2020

The paper analyzes the normal and emergency operation of rural distribution electric networks applying specialized software system - RASTRWIN PC, which is used at many power network enterprises in Russia. This specially designed program uses the RASTRWIN PC calculation core - Astra.dll, which calculates normal and emergency network conditions. It is used to solve the problem of calculating the modes of distribution networks 6-10 kV. To achieve greater accuracy of results, we use the scaling network parameters (currents, voltages, loads). For greater accuracy in calculating emergency conditions, the currents of the previous pre-emergency operation mode are used, as well as the dependence of the load current on the voltage in the network in emergency operation mode. The paper also substantiates the equivalent of the distribution network scheme based on a comparison of the calculation results of the modes for the full network section scheme and a simplified scheme. It is done to reduce labor costs when drawing up a design diagram of a distribution power network with a large number of taps on feeders. Using the developed program for a section of a distribution power network with the voltage 10 kV, normal and emergency operation modes of the network were calculated.
Features and Characteristics of the new NASA MicroPuLse NETwork (MPLNET) automatic rain detection algorithm
Authors: Lolli S. , Welton E. J. , Lewis J. R. , Campbell J. R. , Vivone G.
Published: May 2020

The water cycle strongly influences life on Earth. In particular, the precipitation modifies the atmospheric column thermodynamics through the process of evaporation and serves as a proxy for latent heat modulation. For this reason, a correct precipitation parameterization (especially low-intensity precipitation) at global scale, bedsides improving our understanding of the hydrological cycle, it is crucial to reduce the associated uncertainty of the global climate models to correctly forecast future scenarios, i.e. to apply fast mitigation strategies. In this study we developed an algorithm to automatically detect precipitation from lidar measurements obtained by the National and Aeronautics Space Administration (NASA) Micropulse lidar network (MPLNET) permanent observational site in Goddard. The algorithm, once full operational, will deliver in Near Real Time (latency 1.5h) a new rain mask product that will be publicly available on MPLNET website as part of the new Version 3 Level 1.5 data. The methodology, based on an image processing technique, can detect only light precipitation events (defined by intensity and duration) as the morphological filters used through the detection process are applied on the lidar volume depolarization ratio range corrected composite images, i.e. heavy rain events are unusable as the lidar signal is completely extinguished after few meters in the precipitation or no signal detected because of the water accumulated on the receiver optics.
Trends of Climate Variables and Aerosol optical Depth in Thailand
Authors: Pilahome O , Homchampa C , Kumharn W
Published: May 2020

This study analysed climate variables data in four stations over Thailand. Aerosol optical depth (AOD) obtained from Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) were also used to determine climatic trends in the areas under focus. The linear regression, Mann-Kendall trend, and Sen’s slope tests were applied. Rain (R) gave higher values in July to October for most regions except in the Songkhla. Amount of R increased in all regions. Rainy season is caused by the Southwest monsoon, which is a normal occurrence in Thailand from June to September. However, this monsoon tended to begin earlier and last longer (May to October) than expected. Mean temperature (Tmean) values were found to be significantly higher from March to May and increased in all stations. The highest significant increases of annual Tmean were found in the North. There was no significant trend in annual R (Rainfall) at the 1% and 5% significance level in all stations. The AOD values were likely to increase in almost all stations. The highest significant increase of annual AOD was observed in Ubon Ratchathani.