bluuebunny/crossref_metadata_2025 huggingface dataset:
Variation of Mesh Peel Ply and Gelcoat on Mechanical Properties of Carbon Twill-Vinyl Ester Composites Using Vacuum Assisted Resin Infusion Manufacturing Method
Authors: Nurtiasto T S , Wandono F A , Muzayadah N L , Fazabik R
Published: June 2022

This study discussed the modifications made to the Vacuum Assisted Resin Infusion (VARI) method to make composites. Composites made using the standard VARI method sometimes have values that have not reached the desired standard. In addition, there was a modification to add Gelcoat and mesh peel ply from previous studies that used e-glass fiber and epoxy resin, which positively affected the mechanical properties of the composite. In this study, carbon twill material was used, which is relatively better in mechanical properties than e-glass fiber and vinyl ester resin with different viscosity from epoxy. The finite element simulation was also performed to compare the load versus displacement graph with the testing. The tensile test results of the VARI with double mesh peel ply increased by 1.61%, while VARI with the addition of gelcoat increased 4.34% from the composite with the standard method of 527.62 MPa. The tensile test results of the VARI with double mesh peel ply decreased 17.20%, while the VARI with the addition of gelcoat decreased 30.24% from the composite with the standard method of 29.97 MPa.
Influence of fumed silica and PMMA on optical properties of blue-emitting CH3NH3PbBr3 perovskite nanocrystals
Authors: Ummah Auliya Rahmatul , Mahen Ea Cahya Septia , Nuryadin Bebeh Wahid
Published: June 2022

Fabricating highly efficient and great optical properties of blue organic-inorganic halide perovskite (OIHP) has proven difficult and continues to be a source of significant interest. Herein, we successfully synthesized blue-emitting CH3NH3PbBr3 perovskite using a ligand assisted reprecipitation process, followed by embedding in fumed silica and poly-methylmethacrylate (PMMA) matrix. By adding fumed silica, the photoluminescence (PL) peak spectrum of CH3NH3PbBr3 was blue-shifted from 481 to 477 nm. Furthermore, OIHP also exhibited a blue shift from 477 nm to 471 nm after being embedded in the PMMA matrix. On the other hand, the OIHP absorbance spectrum shifted from 451 nm to 426 nm, which correlates to the blueshift in the PL peak spectrum. The emergence of two peaks in the absorbance spectrum indicates that nanoparticles with small size distribution have grown on the OIHP. This phenomenon demonstrates that the OIHP has a strong quantum confinement effect. Therefore, the results demonstrated that CH3NH3PbBr3/SiO2/PMMA composite films have great optical properties, which is promising for their uses in potential optoelectronic applications.
Investigation on the Mechanical Properties of the Post-Static Fire Testing Effect of Graphite Material used in the RX320 Rocket Motor Nozzle
Authors: Setiadi  , Wicaksono Bagus , Muzayadah Nurul Lailatul , Wandono Fajar Ari , Nurtiasto Taufiq Satrio
Published: June 2022

The rocket nozzle is a crucial and complicated part of a rocket, primarily for rocket RX320. Its function is to control the exhaust flow, so the rocket gets the maximum possible forward thrust. However, graphite materials are used inside rockets due to good mechanical properties and high melting temperature resistance. This study discussed the effect of post-static rocket fire testing on the mechanical properties of graphite materials and compared them with the technical data sheet (TDS) of its graphite. Mechanical properties testing has been done to determine the average flexural strength value with the flexural test method and the average value of the compressive test. The graphite has an average flexural test value of 40.185 MPa, with an average elastic modulus of 0.656 GPa. Furthermore, the average compressive test of graphite has a value of 67.71 MPa, with an average load of 1,560 N. The mechanical properties trends are slightly decreasing due to post static fire testing compared to TDS. It was around 41.2% for flexural strength and 50.7% for compressive strength.
Study of Phase Transformation, Structures, Morphology, and Vibration of Ni-Zn-Co Ferrites Nanoparticles due to Annealing Temperature
Authors: Zuhroh S , Hidayah ASN , Aturroifah NIM , Wahyuni NEA , Utomo J
Published: June 2022

The good physical and chemical properties of metal ferrite nanoparticles can be used as potential materials when applied. This study aims to explore the physical and chemical properties, such as phase, structure, morphology, and vibration of Ni-Zn-Co ferrites nanoparticles annealed at different temperatures. Ni0.4Zn0.5Co0.1Fe2O4 nanoparticles were synthesized by coprecipitation method and characterized by X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared (FTIR) Spectroscopy to determine their structure, morphology, and vibration. Overall, all samples showed spinel cubic structures. In addition, XRD analysis showed the phase transformation from magnetite to hematite by increasing the temperature. The increase of annealing temperature leads to the larger average size of nanoparticles which were estimated by analyzing TEM images. The average diameter of nanoparticles with annealing temperature of 600°C was (10.9 + 0.5) nm and the average diameter of nanoparticles with annealing temperature of 1000°C was (18.6 + 4) nm. FTIR measurements between (4000 – 400) cm-1 confirmed the absorption band in the spectrum. The FTIR spectra of the nanoparticles confirmed the presence of metal ion vibrational bands located at octahedral and tetrahedral sites in 418 cm-1 to 696 cm-1. This implies that Ni-Zn-Co ferrites has truly the spinel cubic structures considering their absorption characteristics at about (500 – 600) cm-1.
Microstructure Investigations of Phase Transformation in Cold Working AISI 316L Austenitic Stainless Steel
Authors: Rivai Abu Khalid , Shabrina Nanda , Sugeng Bambang , Sukaryo Sulistioso Giat
Published: June 2022

Development of high temperature and corrosion-resistant materials is one of the key issues for the deployment of advanced nuclear reactors and also to accommodate the problem that occurred in the conventional reactor as the lesson-learned from Fukushima Daiichi nuclear reactor power plant accident. One of the high performance materials for that purpose is austenitic stainless steel such as AISI 316L that widely used for power plant. In this study we investigate the characteristics of AISI 316L austenitic phase transformation if cold working is applied. In general, during the cold working process the mechanical characteristic and the phase of the austenitic steel will change. It is expected that the characteristic of AISI 316L austenitic steel will be improved by optimum cold working mechanism. Cold working of AISI 316L austenitic steel at various percentage reduction of 5%, 15%, 25% and 38% have been done. Afterward, the sample was characterized using X-Ray Diffraction and Optical Microscope to analyze the microstructure characteristics and phase transformation. The results showed that the phase transformation in AISI 316L austenitic steel occurred from austenite – gamma (FCC: Face-Centered Cubic lattice) to martensite – alpha prime (BCC: Body Centered Cubic lattice). The percentage of martensite phase was increasingly growth related to the increasing of the percentage of cold working value i.e. 8.3%, 21.6%, 29.6% and 37.1%, respectively. The hardness of AISI 316L austenitic steel increased with the increasing of the cold working percentage. AISI 316L double phases which covers of austenite-martensite intermix phase structure with higher hardness mechanical properties has been successfully developed.
Microstructure Investigation of Mechanically Alloyed 316L-6Al-0.5Y2O3 Oxide Dispersion Strengthened Austenitic Steel Powder
Authors: Rivai Abu Khalid , Pratama Kandias Ahmad Muzaqi Nafsah , Sugeng Bambang
Published: June 2022

Development of accident-tolerant fuel cladding (ATFC) materials for LWRs (Light Water Reactors) is being intensively carried out in many research centers in the world as the lesson-learned from the Fukushima Daiichi nuclear reactor power plant accident. One of the advanced high temperature materials which is intensively developed is Oxide Dispersion Strengthened (ODS) steel. The strengthened mechanism is generated by homogeneous dispersion of nano-meter sized ceramic oxide particles in the matrix of the steel which is done by mechanical alloying technique so called mechanosynthesis. Synthesis of an austenitic ODS steel powder of 316L with additional element of 6 wt.% aluminum and dispersion of nano-particles of 0.5 wt.% yttrium oxide (yttria: Y2O3) has been done. The aim of the research is to achieve a better performance of 316L austenitic steel as the proven material for power plant at elevated temperature by modified to become ODS austenitic steel with additional of aluminum. Mechanosynthesis was done using High Energy ball Milling (HEM) for 30 hours with BPR (Ball to Powder Ratio) of 10:1. Afterward, the sample was characterized using Scanning Electron Microscope-Energy Dispersive Spectroscope (SEM-EDS) and X-ray Diffraction (XRD) to analyze the microstructure characteristics. The results showed that the alloying between 316L and aluminum powders was formed. Furthermore, crystal grains and the particles of 316L-6Al-0.5Y2O3 steel powder was much smaller than as received 316L austenitic steel and aluminium powders. The particles size and element composition was homogeneously distributed. The results showed that the parameters of mechanical alloying for development of 316L-6Al-0.5Y2O3 ODS austenitic steel powder have reached the optimum condition.
Nuclear Energy Contribution for Net Zero Emission and National Energy Mix 2060 in Indonesia
Authors: Permana Sidik , Trianti Nuri , Rahmansyah Adi
Published: June 2022

Indonesian Government has strongly announcement to the public which is in line with the Paris Agreement that has been signed and ratified with other 164 countries across the globe to fulfil their commitment to reduce the greenhouse gas effect. In 2060, the estimated total demand market of about 1800 TWh which is consist of about 300 TWh of electric demand in the present status which will be required additional new energy supply of about 1500 TWh. This new additional energy which is about five times larger than the present energy which leads to more energy resources and alternative energy supplies are required. Meanwhile, fossil fuels as main producer will be reduced and NRE will be utilized more, and it is increased gradually to maintain the energy demand as well as reducing the CO2 emission to the net zero target. In the present study, the contribution of each energy resources especially for the contribution of nuclear power plant (NPP) will be evaluated as a part of national energy mix. The evaluation of nuclear energy contribution is needed to estimate the electricity contribution level as well as the contribution to reduce the CO2 emission and it will compare to other energy resources as comparable analysis. Nuclear power plant requires the lowest install capacity of 211 GWe followed by waste power plant, geothermal and the highest installed capacity was solar PV power plant which requires 765 GWe to produce 1500 TWh electricity for a single 100% power plant. It can be seen the reduction GHG from more than 1300 Mton GHG release from coal can be reduce significantly by NRE of about more than 95% of reduction factor. Total electric contributions based on all energy mix, and it shows nuclear energy contributes 247 TWh (16,5 %) in total 1500 TWh.
The Space-Time Autoregressive Modelling with Time Correlated Errors for The Number of Vehicles in Purbaleunyi Toll Gates
Authors: Mukhaiyar U , Nabilah F T , Pasaribu U S , Huda N M
Published: June 2022

The space-time modelling considers the observations dependence based on time and spatial simultaneously. One of popular models used is the Generalized Space-Time Autoregressive (GSTAR). Most of the GSTAR class models assumed that the errors are uncorrelated and normal distributed. In fact, the dependence of errors is exist. In this paper, the GSTAR model is assumed to have the time correlated errors. The convergence of the parameter estimators is evaluated and the weak consistency is obtained. The illustration is performed by using the number of vehicles passed through Purbaleunyi toll gates. For this data, the GSTAR models be applied and compared between the uncorrelated and time correlated errors assumption of modeling. It is obtained that the GSTAR(1;1) model with time correlated errors, is more appropriate model to predict the number of vehicles passed through the Purbaleunyi toll gates. This appropriate model is well performed when the minimum number of time observations is more than sixty observations.
Natural, Meteorology, And Novel – IAP Data Processing Method for Tipping Bucket Based Rain Gauge
Authors: Rachmawati L M , Mardiansyah A , Kinanti I W , Ramadhan A , Adiwidya A S , Jalasena A , Chandra I
Published: June 2022

Air pollution transport is entangled with weather and climate factors. As the pollutants tend to move due to the metrological condition. Naturally, pollutants will be deposited to the ground at the end part of the deposition cycle. One of the factors of pollutant deposition in a wet deposition is rain. The soluble pollutants and particulate matter are precipitated to the earth’s surface during precipitation. In order to analyse it, we need a rainfall measuring device/rain gauge, as rainfall is an important parameter to find the correlation between the two. However, there is a limited number of rain-gauge in Indonesia. Thus, we proposed a tipping bucket rain gauge, which consists of a funnel, a bucket, a magnetic switch sensor, and a microcontroller-based processing unit. The prototype is equipped with a GSM module so that the data can be sent in real-time via text message every minute, also an SD Card as the backup storage data. It was calibrated using ISO 17025:2005 standard, the result obtained by a resolution of 0.2 mm/tip with a capacity of 4.2 ml buckets, and U95 uncertainty of ±0,04 - ±0,12 mm/minute. To find the suitable method of rainfall calculation for the prototype, we observe three methods, Natural, Meteorology, and Novel-IAP. From the three we found, Novel-IAP has the best result since the calculation is executed every second. And the other methods are found to have a high error result.
Spatial Modelling of Indoor Air Pollution Distribution at Home
Authors: Putri A N A R , Salam R A , Rachmawati L M , Ramadhan A , Adiwidya A S , Jalasena A , Chandra I
Published: June 2022

In ancient times, humans were very accustomed to depending on nature, so that in the past humans held the title as an outdoor species. Over time with many technological advances, the pattern of human life has shifted to being an indoor species. Currently, almost 55% of the world’s population lives in urban areas and is projected to increase to 68% by 2050. Based on the National Human Activity Pattern Survey (NHAPS), the total time humans spend indoors is 86.9%. Research shows that air pollutants contained in indoor air are 2 to 5 times more than outdoor air. The neglect of the air conditioning system also worsens indoor air quality. It is often found that the supply of fresh air and the concentration of pollutants in the work or activity zone is unknown, even though this is a crucial matter. With the amount of time spent indoors, air quality and the distribution of pollutants in indoor air becomes very important. This research was conducted spatial modelling of air pollutant distribution using the kriging interpolation technique. The results of spatial modelling with this method produce an average of R-squared=70,98% dan RMSE = 0.03. Several factors influence the increase in pollutant concentrations that are the activity of the occupants, the number of occupants, and environmental conditions outside.
A Simple and Low-cost Photocatalytic Air Purification Test Method
Authors: Adhi P M , Rahman H , Nuriskasari I , Syamsudin  , Syahrom A
Published: June 2022

The application of photocatalytic oxidation (PCO) in air purifiers (AP) to remove viruses, bacteria, and toxic gases in the air is intensively being studied, especially after the Covid-19 pandemic broke out. The testing method of PCO materials for AP purposes has been standardized through ISO 22197-4 (2013). However, the standard required a set of complex, high precision, and costly equipment. The present study demonstrates a simpler and low-cost test setup without compromising any accuracy in the overall result. The proposed test consists of a test chamber and mixing chamber, and sets of equipment installed in it. A 3D printer fabricated a PCO reactor, and TiO2 was coated on the surface. Formaldehyde (HCHO) is used as a sample pollutant to be observed, injected into the test chamber. Before the measurement of the concentration of HCHO, the intensity of UV A LED was measured. Then, the amount of formaldehyde concentration was monitored online by indoor air quality measurement equipment. The result shows that the intensity of UV light was enough to generate a photocatalytic oxidation reaction. After 20 minutes of reaction, the HCHO concentration inside the chamber was decreased around 21.76%.
Analysis of seawater intrusion into groundwater in the coastal area of Durung Village, Aceh Besar Regency, Aceh Province, Indonesia
Authors: Arfah M , Tanjung M , Syahreza S , Hartati D V
Published: June 2022

Durung Village is a region consisting mostly of coastal and hilly areas. Utilization of groundwater in the coastal zone has been increased these recent years for all purposes of life, from drinking to sanitation and from industry to agriculture. It results new environmental problem, such as seawater intrusion that caused negative impact on groundwater resources. This research aims to analyze the effect of seawater intrusion into the groundwater in the study area. Total Dissolved Solids (TDS) was used in this research as approximation of groundwater salinity value. The spatial distribution of seawater intrusion had been prepared by using Geographic Information System (GIS) spatial interpolation technique for TDS parameter. The results revealed that seawater intrusion presented more obviously near the coastal line and its northern part was the most affected area by this contamination indicated by the highest TDS value of 2.947 mg l-1, whereas the farther location from the coastline were free of seawater intrusion indicated by low TDS values between 181 – 579 mg l-1.
Experimental investigation of pile characteristics of non-spherical particles mixtures: pile height and angle of repose
Authors: Widartiningsih P M , Putra M I R , Aji D P P , Rudiawan A N F , Viridi S
Published: June 2022

An angle of repose is defined as the steepest angle of a conical pile that is naturally formed when a bulk of particulate solid is poured onto a flat surface. It has been considered as one of the important properties in characterizing granular material due to its effectiveness in determining flowability of granular, pile profile in an opaque container, and granular transportation system. Since the angle of repose is sensitive to the shape of individual particles, investigations through experiments and simulations for various forms of particles have been carried out. However, most of them were performed under homogeneous particle systems. While in practical situations, granular mixtures consisting of a variety of particle shapes are commonly employed. This study presents an experimental investigation of angles of repose resulting from a mixture of two types of non-spherical particles with different values of roundness. Experiments have been carried out with different compositions and have been repeated five times to ensure their reproducibility. The results show that the angle of repose linearly corresponds to the granular composition, where the coefficient of determination is ~0.95. Therefore, the effect of granular composition in binary mixtures on the characteristics of the resulting pile has been demonstrated in this study.
Geometry Effect of CaCl2·6H2O at Charging and Discharging Process as Latent TES
Authors: Yusuf Akhmad , ‘Ulhaq S D , Wonorahardjo S , Sutjahja I M
Published: June 2022

Phase Change Materials (PCMs) as thermal energy storage can store a relatively large amount of latent heat at a relatively constant temperature during the solid to liquid (melting process), or vice versa. With many applications of PCM as temperature regulation such as for building application, heating, or cooling devices for battery, electronic, food preservation, and medicine, the geometry effect is significant to optimize its performance because each type of application requires a specific kind of geometry. This paper reports the simulation study for the charging and discharging an inorganic PCM of CaCl2·6H2O (melting temperature 29 °C) using Ansys fluent for various 3D and 2D geometric shapes, consisting of the sphere, cylinder, and rectangular solid. The density, heat capacity, thermal conductivity, and viscosity as the input parameters were taken or extrapolated from previous experimental studies. The simulation study results consisting of time-dependent temperature for melting and freezing transition and time-dependent liquid mass fraction can be used to optimize the CaCl2·6H2O as the medium of thermal energy storage (TES) as the medium of thermal energy storage (TES) for a specific application.
Absorber Geometry Size Optimization For Acoustic Anechoic Chamber Design Using Genetic Algorithm
Authors: Christian J , Suprayogi  , Fitriyanti N
Published: June 2022

An anechoic chamber is a room that is made to resemble the condition of empty space. This room has an absorption rate of 99%. The absorber is an essential part while manufacturing an anechoic chamber. In an anechoic chamber, absorber affects in terms of absorption and frequency range. Specification of the absorber used depends on the specification of the anechoic chamber to be made. The optimum absorber geometry size is required to maximize the net volume of the anechoic chamber. The maximum measurable object size is 0.05x net volume of an anechoic chamber. To overcome the problem, it is necessary to optimize the size of the absorber geometry. The size optimization of the absorber geometry has been carried out using a genetic algorithm with MATLAB as the programming software. The incidence angle of the wave and the width of the absorber are used as input parameters for absorber optimization. Absorber geometry size optimization results in an optimum peak angle and absorber length. The width of the absorber used in this optimization is 0.2 m. The peak angle obtained is 12.2° with a length of 0.936 m. The average absorption coefficient obtained is 0.886041.
The Optical Response of Metallic Spherical Core-Shell Nanoparticles
Authors: Fitriyadi  , Azwar Azrul , Noor Fatimah Arofiati
Published: June 2022

The optical response of spherical nanoparticles was studied based on the quasi-static approximation of classical electrodynamics. The simple Drude model was used to calculate the complex dielectric function of the metal. We investigated the behavior of the absorption cross-section spectra of metallic spherical core–shell (including dielectric-metal and metal-dielectric) nanoparticles numerically. We found that the number of resonance peaks in the absorption cross-section spectra depends on the number of metal-dielectric interfaces of the nanostructure, as predicted by plasmonic hybridization theory. Furthermore, the absorption cross-section spectra can be precisely controlled by changing the thickness of the shell and the dielectric constant of the medium.
Calculation of spectra and plasmon wave distribution in one-dimensional periodic structure
Authors: Fariz Alvin , Hidayat Rahmat
Published: June 2022

Surface Plasmon Resonance (SPR) is a resonance phenomenon between electromagnetic waves and electrons, which is formed on the interface between metal and dielectric surface. SPR waves can be generated by using a coupler element, such as prisms and gratings. In this study, we analyzed the effect of groove filling in nanograting structures using computation work based on Rigorous Coupled Wave Analysis (RCWA) method. The structure periodicity is 700 nm with a groove depth of around 350 nm. The reflectance spectra calculation by the RCWA method produces the appearance of SPR dip for an empty groove (with air inside the groove) at around 550 nm - 650 nm. The dip wavelength varies on the incident angles from 30 up to 60 degrees. In addition, the shifting of those dips is also predicted from the calculation results when the groove is filled by a medium with a refractive index of 1.5, which can be the basis of its utilization as optical sensing elements.
Density Functional Theory Study of Oxygen Deficiencies in SrCoO25
Authors: Wilbert Kevin , Pradipto Abdul-Muizz , Agung Nugroho A.
Published: June 2022

We report the effects of oxygen deficiency to the electronic and magnetic properties of SrCoO3 calculated using spin-polarized Density Functional Theory. The correlation effects of the Co 3d orbitals are considered explicitly using the effective Hubbard U
eff parameter. The U
eff consists of the subtraction between the U value of 3 eV to denote the Coulomb interaction and the Hund’s coupling parameter J of 0.95 eV. Our results show that the localized character of the Co 3d orbitals strongly depends on the oxygen content. The magnetic exchange interaction between two neighboring Co ions is therefore altered. As a consequence, a change of magnetic ground state using the same U
eff value from ferromagnetic ordering in full oxygen content to antiferromagnetic ordering in SrCoO2.5 is obtained.
Possible signature of entanglement in null-energy-condition-violating inflation
Authors: Prihadi H L , Zen F P
Published: June 2022

In recent years, the classical version of the null energy condition (NEC) has been enhanced into its quantum generalization, the quantum null energy condition (QNEC). The right-hand side of the QNEC inequality is non-zero; it is multiplied by a factor of ћ and recovers the standard NEC in the classical limit. Moreover, the second derivative of entanglement entropy also plays a role in determining the right-hand side. In this work, we study several examples of theories of inflation that violate the standard NEC, yet still, possibly obey the QNEC. This suggests that the deviation of the standard NEC arises due to the existence of entanglement between regions inside and outside of the cosmological horizon. Possible connection to quantum fluctuations of de Sitter spacetime is also studied.
Analysis of gravitational waves from inflation model with minimal, non-minimal, and non-minimal derivative coupling of scalar field from Horndeski theory
Authors: Djogama M Z , Hikmawan G
Published: June 2022

Inflation theory provides solutions for problems in cosmology, such as horizon problem and flatness problem. The study of Gravitational waves production in cosmic inflation era not prove the general inflation theory, but also to differentiate in detail among specific models. In this research, we use inflation model with minimal, non-minimal, and non-minimal derivative coupling of scalar field without potential from Horndeski Theory. From this model, we calculate scalar and tensor perturbation equations and then obtain its equation of gravitational waves, spectral index for each perturbation mode and tensor-to-scalar ratio. Spectral index and tensor-to-scalar ratio nearly scale-invariant and agree with observational data for some Ho, ζ, and ξ. Gravitational waves remain constant during inflation and start oscillates when its modes enter the horizon. Energy of this gravitational waves is scale-invariant for modes that re-enter horizon during radiation dominated era and rises toward lower frequencies.
Numerical Analysis of Non-minimal Coupling and Non-minimal Derivative Coupling Models using Direct Random Method
Authors: Rusyda M B , Suroso A , Hidayat W
Published: June 2022

In this work, we studied classes of Horndeski theory, specifically the Non-minimal Derivative Coupling (NMDC) ‘model and Non-minimal Coupling (NMC) model, against the observation of gravitational waves using the numerical framework given by Arai and Nishizawa. The framework takes randomized set of parameters of the theory, filters results that disagree with the late-time evolution of the universe and the stability condition, and outputs observable quantities of gravitational waves (GW) that were then compared to the quantities obtained from observational data of gravitational waves detection.
Study on optical properties of carbon nanodots by annealing of rice powder as a carbon source
Authors: Jaya M. , Johanes A. Z. , Pingak R. K. , Ngara Z. S.
Published: June 2022

In this work, we present the fabrication process and analyze the optical properties of carbon nanodots (C-dots) from rice powder taken from Kupang regency, East Nusa Tenggara Province. The rice powder was annealed at 400oC for 30 minutes to obtain a black powder. This sample (0.5 gram, 3 mL ethanol) was sonicated for an hour, and ethanol (10 mL) was added again for the centrifugation process at 1000 rpm for 20 minutes. Furthermore, the ethanol solution was filtered to realize C-dots. By irradiation with a UV lamp at 365 nm, C-dots emitted blue emission color, and they have absorption peaks at a wavelength of 276 nm. Upon excitation wavelength (λexc) of 350 nm, their fluorescence (FL) spectrum range is from 360 to 650 nm with maxima FL intensity at 436 nm corresponding to blue emission color as well as high photostability. The appearance of O-H and C=O bonds indicates that the surface of C-dots was coated with hydroxyl and carbonyl groups. Therefore, the blue emission color and excellent photostability of these C-dots can pave a large opportunity to explore the C-dots from rice powder as a functional material in electronic devices such as sensors, light emitting diodes, and so on forth.
Preparation of Bimetallic Metal-Organic Framework Derived from Spherical Ni-Co Glycerate Template
Authors: Adli Muhammad Zimamul , Irzaman  , Nugroho Widagdo Sri , Rusydi Febdian , Nugraha
Published: June 2022

Bimetallic Metal-Organic Frameworks (MOFs) have attracted significant interest due to its high specific surface area and tunable porosity, leading to high sensitivity and catalytic activity. Amorphous MOF presents many opportunities as new functional materials especially in electrochemical applications. In this preliminary study, we explored the preparation, properties, and applications of amorphous MOF. It studies on the characteristics of Ni/Co-MOF synthesized through self-template using uniform Ni-Co glycerate spheres. Nickel and cobalt are active electrode materials with similar properties and atomic radius, and have much possible coordination with ligands so that they can be found in many types of MOFs. In this work Ni-Co Glycerate, produced in powder form, was used as the source of metal ions, 2-methylimidazole (H-MeIM) as the ligand, as well as aquabidest and ethanol as the solvents. The MOF was produced in two-step processes i.e. glycerate formation with solvothermal and MOF formation at room temperature. From the XRD test, no peak was observed, showing that the Ni/Co-MOF is in an amorphous phase. The results of the Scanning Electron Microscope (SEM) analysis showed that the Ni/Co-MOF has spherical shape covered by nanosheets, confirming the amorphous state.
DFT study on gas-phase decomposition of ethylene carbonate in the presence of LiPF6, LiBF4, PF6
-, and BF4
-
Authors: Naufal F D , Lasiman E T , Syafira A Z F , Anshor M F , Setianto D , Ubaidillah A , Rendy B , Komalig R W M , Nuruddin A , Saputro A G , Shukri G
Published: June 2022

The decomposition of Li-ion battery (LIB) electrolyte has been a well-known challenge that needs to be overcome. The most common electrolyte on lithium-ion batteries is LiPF6 which has all-balanced properties, while LiBF4 has been proven for its superior stability. These lithium salts are often dissolved in Ethylene Carbonate (EC) to form liquid electrolyte systems. In this work, we investigate the decomposition mechanism of EC in the presence of LiPF6, LiBF4, and their delithiated counterpart by means of first-principles density functional theory (DFT) calculations. We found that the energy barrier of decomposition on LiBF4 presence is 0.42 eV lower than on LiPF6 presence, also on BF4
- presence is 0.22 eV lower than PF6
- presence. This suggests that LiBF4 and BF4
- presence reduces EC stability more than LiPF6 and PF6
- anion. Moreover, the presence of Li+ ion increases the energy barrier of decomposition (about 0.79 eV on PF6
- case, 0.59 eV on BF4
- case) but decreases enthalpy change significantly (about 1.58 eV on PF6
- case, 1.43 eV on BF4
- case). This suggests that while the Li+ ion causes the decomposition to be slower, its presence destabilizes the EC more.
Building a Science Kit of Faraday’s Law with Free Fall Motion Method
Authors: Lutfiana S , Pujayanto  , Haryani F F
Published: June 2022

The aim of this study is to build a science kit of Faraday’s Law with free fall motion method. The magnetic flux comes from several neodymium magnets and the coil is made of copper. The moving magnet falling through the coil causes a change in the magnetic flux and produces an induced emf. The data analysis technique used in this research are graphical method and analysis of Faraday’s Law equations with another supporting equation. Based on the results of this study, the conclusion is the induced emf value is directly proportional with the change of the magnetic flux and also has a directly proportional with the number of turn of coil, thus it can be obtained the mathematical equation of Faraday’s Law

ε
=

d
ϕ
B

d
t
Study of Eclipsing Binary Physical Parameters. Case: CV Boo
Authors: Rahma Aliyya Nur , Putra Mahasena , Hakim Muhamad Irfan , Aprilia  , Sugianto Yayan
Published: June 2022

Eclipsing binary (EB) is a binary system in which the components are seen eclipsing each other from the Earth. Photometric and spectroscopic observation of EBs show variation on their brightness (light curve) and radial velocity (velocity curve). Light and radial velocity curve analysis provide physical and geometrical parameters of the binary systems and their components, which are very important in stellar evolution studies. These parameters are determined by solving inverse problem, i.e. finding the best-fitting model to the observational curves. Modern EBs modeling programs include detailed physics of stellar atmosphere, geometry, and dynamics of the binary system. One of such models is PHOEBE (PHysics Of Eclipsing BinariEs) 2.3, which offers sophisticated methods to solve the inverse problem. It is solved by computing model curves from initial (estimated) parameters, optimizing them numerically, and sampling the optimized models. We studied CV Boo, a detached EB with a period of 0.847 days, using PHOEBE 2.3. Light curve and radial velocity curves were obtained from the literature. We discuss the steps in finding the solution, present our best solution of the inverse problem, and compare our results with previous studies.
Non-Markovian entanglement dynamics of three independent qubits within atomic-cavity system
Authors: Kosasih J S , Wasesatama V A
Published: June 2022

All realistic quantum systems will interact with their environments. This fact presents challenges to the implementation of quantum systems for practical systems. One of the most important quantum resources is the implementation of entanglement. In this paper, we investigate the interplay between the effects of noisy environments and the dynamics of entanglement. The open quantum system model that will be used is cavity quantum electrodynamics (CQED) with three-qubit interacting independently with a variation of environmental model. We use master equation to describe the dynamics of the open quantum system and a lower bound concurrence (CLBC
) to measure the entanglement of tripartite qubit. We derive the exact dynamics of each model and use CLBC
method proposed by Li et.al to visualize entanglement dynamics. By adjusting the environmental parameters, we also found revivals and dark-periods of entanglement which are unique to non-Markovian processes.
Photoluminescence Properties of CsPbCl3 and CsPbBr3 Nanocrystals synthesized by LARP Method with Various Ligands and Anti-solvents
Authors: Yandri Valdi Rizki , Wulandari Priastuti , Hidayat Rachmat
Published: June 2022

Cesium lead halide (CsPbX3; X= Cl, Br, I) is inorganic materials that can be used for the absorber of Perovskite solar cell and active layer of sensor. In this research, synthesis of cesium lead chloride (CsPbCl3) utilizes cesium chloride (CsCl) and lead (II) chloride (PbCl2) as raw materials then oleic acid and linoleic acid are used as ligands. CsCl and PbCl2 can be utilized to synthesize CsPbCl3 by using ligand-assisted reprecipitation (LARP) method at room temperature. Dimethyl Sulfoxide (DMSO) is used as the solvent of CsCl and PbCl2 to form 0.1 M solution. Similar to CsPbCl3, synthesis of CsPbBr3utilizes CsBr and PbBr2 at room temperature. Antisolvent used in this experiment are chloroform, toluene and tetrahydrofuran (THF) for colloidal solution CsPbCl3 and CsPbBr3. This research will analyze the impact of different ligands and different antisolvent, so it will be obtained the most suitable ligand and antisolvent for CsPbCl3 and CsPbBr3. The wavelength of photoluminescence spectra for samples of CsPbCl3 and CsPbBr3 colloidal solution are 434.00 nm and 512.82 nm. Based on transmission electron microscope (TEM) results, nanocrystals have been formed in samples of CsPbCl3 and CsPbBr3 colloidal solution. Powder samples of CsPbCl3 and CsPbBr3 can be obtained by heating at 190°C (the boiling point of DMSO) then CsPbCl3 and CsPbBr3 are identified in each powder sample by x-ray diffraction (XRD).
Research and Design of An Early Warning System for Emerging Infectious Diseases Based on UWB
Authors: Wang Xiaohong , Han Hongbin , Lin Yuting , Ma Qingbian , Zhu Xianghao
Published: June 2022

Aiming at the problem of cross-infection in hospitals and other areas of infectious diseases, we designed a system based on ultra-wideband and using TDOA positioning method combined with smart wearable devices to realize health warning and contact trajectory tracking of medical staff. In the hospital area with stricter management, we obtain the user’s consent and wear smart bracelets to the users. These bracelets are used for positioning and temperature detection.. First, we model the indoor area based on the measurement data of the indoor area and install the base station, use the ultra-wideband technology combined with the wireless time synchronization TDOA method to achieve high-precision positioning in the indoor area, and use Kalman filter to filter the positioning noise data. Then, it combines the body temperature detection data of the wearable bracelet and the system positioning data to establish a user track tracking service to further record the user’s activity range. In addition, the area is strictly controlled, the trajectory of the infected person is restored and the contact person is quickly located, and timely warning can be provided through information such as electronic fence and body temperature. The system can trace the source of regional outbreaks of infectious diseases, provide health warnings for users, and quickly locate the relevant contacts of virus carriers.
Exploration on Homogenization of Threshing and Redrying Products in Qujing Cigarette Factory
Authors: Sheng Xiaohe , Wang Rui , Zhu Yi , He Xiaoqiang , Guo Ge
Published: June 2022

Take homogenization as the main line of threshing and redrying, promote the extension of homogenization production from quality concept to management mode, firmly establish the concept of "process to ensure product quality", and ensure the homogenization of finished product quality with process homogenization. The method of normal distribution and central value collocation was used to solve the requirements of homogenization collocation of unknown material components. The frequency normal distribution map of tobacco nicotine value and the central value were used for warehousing, and the warehousing of raw materials was realized by the combination of nicotine value interval chemistry or central value. After the detection of chemical composition of raw materials, the warehousing task was issued on the vehicle terminal based on the digital warehousing logistics system to remind and monitor the forklift operation task. Through the exploration of homogenization of threshing and redrying products, the homogenization standard module ratio is calculated, and the ratio is based on the nicotine value of tobacco leaves in the chemical composition of the original tobacco, which effectively solves the imbalance of human factors in the current ratio. At the same time, combined with information technology, the information transmission function of forklift vehicle terminal is realized.
SuperDetector: A Framework for Performance Detection on Vulnerabilities of Smart Contracts
Authors: Dai Meiyi , Yang Zhe , Guo Jian
Published: June 2022

The technology of Ethereum blockchain enables the implementation of smart contracts. Nowadays smart contracts are one of the most successful applications of blockchain technology, which are widely used in many fields, such as finance, energy and services. The decentralization and immutability properties of Ethereum blockchain provide security for transactions from smart contracts. However, these properties are possible to lead to unfixable vulnerabilities of smart contracts. In recent years, vulnerability detection on smart contracts has attracted more attention from researchers and many related tools have emerged. Nevertheless, the existing vulnerability detection tools have not yet been put into formal use. Due to the lack of suitable smart contract sets and fair metrics with other factors, it remains complex work to conduct authoritative performance tests on these tools. In this paper, we first summarize eight common vulnerabilities of smart contracts, and then divide them into call-related and call-irrelated vulnerabilities according to whether they involve caller functions or not. In addition, we propose a detection framework called SuperDetector, which combines a variety of vulnerability detection tools based on static analysis technology. And the framework mainly measures the detection performance, which contains vulnerability coverage, detection accuracy, usability and execution time on the two types of vulnerabilities. The results indicate that the framework can analyze the performance from different perspectives, and the performance of vulnerability coverage and detection accuracy on call-related vulnerabilities is much better than that on call-irrelated vulnerabilities. Finally, we design a selector based on the detection results in the framework for improving the vulnerability coverage and detection accuracy.
Prediction and Application of Network Business Traffic based on LSTM
Authors: Lv Tiantian , Wang Ying , Yuan Jingjing , Wu Yanqin , Zhang Le
Published: June 2022

Traffic prediction is the basis for guiding bandwidth adjustment in the process of network operation and maintenance. Most of the existing traffic prediction models focus on network traffic prediction based on a single model or single characteristic, and cannot accurately predict whether the current bandwidth can meet user requirements. This paper proposes a prediction method of network traffic based on the long short-term memory (LSTM) model. Based on LSTM model, the traffic interval deviation and the network traffic are predicted, and the two prediction results are combined, then the network traffic interval is predicted. First, this study uses the historical data from 2019 to 2021 to predict the historical deviation value in February based on the LSTM model, and then predicts the traffic interval on October 2021 based on the historical data in September 2021, and compares it with the bandwidth whether the forecast is out of bounds. Finally, compare with other models, including Auto Regression Model (AR), Moving Average Model (MA), Autoregressive Integrated Moving Average Model (ARIMA) and linear regression model, the precision rate(p), recall rate(r) and comprehensive value(f) are all higher than those of the other two models, which proves the reliability of the LSTM model.
Experimental Measurement and Markov Chain Modelling of Stroke Order Intuition
Authors: Xin Yong , LYU Ruimin
Published: June 2022

As a feature of Chinese characters, stroke order plays an important role in Chinese character education, Chinese character recognition and handwriting identification. However, in recent years, the research on stroke order is limited to elaboration and supplementation of existing stroke order and stroke order rules. There is no special research that focuses on the principle behind stroke order. To quantify the internal regularity of stroke order, we start with the stroke order intuition in the actual writing. Because stroke order has individual differences, we select a group of students with small differences as testers. In this paper, we design an algorithm to generate random strokes and collect the timing data during testers copying strokes. After pre-processing the collected data, a Markov chain is introduced to model stroke order intuition, which can divide the stroke sequences into three states. And then we classify them into three situations according to the stroke distribution. Next, we compare them with some well-known stroke order rules. The results show that the probability distribution of strokes in different situations is not always consistent with the empirical rules, as well as the relations between them.
Short-run Wind Power Combination Projection Model based on CEEMDAN-TPA-TCN-MRFO
Authors: Yuxin YE , Xiaodong SHEN
Published: June 2022

Wind power is playing an increasingly critical role in new energy sources. In order to modify the precision of short-term wind power prediction, this thesis proposes a combined model for short-term wind power prognosticate based on Complete Ensemble Empirical Mode Decomposition of Adaptive Noise (CEEMDAN), Time Pattern Attention mechanism (TPA), Time Convolution Network (TCN) and Multi-strategy Manta Ray Foraging Optimization (MRFO). Firstly, this thesis uses CEEMDAN algorithm decompose the wind power sequence, and obtain the sub-sequence components. Combined with key meteorological variable data, this thesis constructs a training set. Then, it optimizes the convolutional network hyperparameters with MRFO. Finally, the final forecasting value is obtained after reconstructing the forecasting results by predicting sub-sequence components respectively with TPA and TCN. The practical cases reveal that the propound combined forecasting model can better predict the wind power change trend. Compared with other methods, this model can significantly improve the short-term presaging accuracy of wind power.