bluuebunny/crossref_metadata_2025_split huggingface dataset:
Photoluminesence study of undoped GaAs at temperatures 300 K and 77 K
Authors: Amaliya V F , Yuniati A , van Dommelen P 
Published: March 2021

Abstract
This work presents an experimental study of photoluminescence spectra from GaAs thin layer at temperature 300 K and 77 K. PL spectra were used to investigate the characteristics of the material, such as the photon energy, gap energy, and the type of radiation transition. The apparatus used in the experiment are green laser with a wavelength of 532.0 nm, laser power supply, 500 mm focus lens, ocean optics USB 2000 spectrometer, fiber optic cable, USB cable, and the computer software installed ocean view and origin pro. The characterization was carried out at temperatures of 300 K and 77 K with power variation in the range 40 mW - 150 mW. The emitted spectrum was analyzed by observing the wavelength and calculating the photon energy and the gap energy. The results showed that laser power variation does not affect the emitted wavelength. However, it is affected by temperature. The emitted wavelength is 840 nm at 300 K and 790 nm at 77 K. The value of gap energy at 300 K is 1.422 eV while at temperature 77 K is 1.519 eV. The photon energy at temperatures 300 K and 77 K were 1.465 eV and 1.560 eV, respectively. The type of transition is a band-to-band transition at 300 K and Free Exciton (FE) at 77K. These results are consistent with existing theories, so the characterization of undoped GaAs has done successfully.
Effect of pyrolysis temperature on bio-fuel quality produced from pine bark (Pinus merkusii) by pyro-catalytics method
Authors: Jahiding M , Arsyad W O S , Rif’ah S M , Rizki R S , Mashuni  
Published: March 2021

Abstract
This study aims to determine the effect of pyro-catalytic temperature on the quality of bio-fuel. Bio-fuel quality analysis includes: density, viscosity, calorific value, and composition of hydrocarbon compounds using Gas Chromatrography-Mass Spectrometry (GC-MS). The pyro-catalytic process was carried out at a temperature variation of 400, 500 and 600° C with each addition of 5% zeolite catalyst to the mass of the sample used. Results showed the best bio-fuels were obtained at a temperature of 500° C with viscosity of 21.39 cP, density of 0.9884 gr / ml and calorific value of 10.367 kcal / kg. Analysis composition of fuel content in bio-fuel using GC-MS obtained acetic acid, phenol, furfural, pyridine, creosol, benzene, ethanol and cathecol with a fuel percentage of 66.51% at 500° C, so as to produce bio-fuel from Pine bark (Pinus mercusii) can be used as an energy source (alternative fuel).
Determination of Electron Excitation Temperature in an RF-DC Hollow Cathode Nitrogen Plasma
Authors: Windajanti J M , Santjojo D J D H , Pamungkas M A , Abdurrouf  
Published: March 2021

Abstract
An RF-DC nitrogen glow discharge generated inside a rectangular hollow cathode was investigated as a source of nitrogen atoms. The plasma was produced at a frequency of 2 MHz at a low-pressure condition at the range of 30 to 100 Pa. The power generator was controlled at the RF voltage of 150 V and DC bias voltage of -500 V. The atomic nitrogen species have been detected by employing an optical emission spectroscopy technique. The use of a rectangular hollow cathode proves that the increase of nitrogen atoms species at a wavelength range of 700-900 nm was produced from the dissociation process of molecular nitrogen species. The present work aims to determine the electron excitation temperature based on the OES spectra. The excitation temperature was calculated by using the Boltzmann plot method. The result is the excitation temperature determined at the range of 0.59 to 0.71 eV. The excitation temperature in the hollow cathode was decreased with the increasing pressure.
Effect of Nd3+ substitution on the BHmax properties of barium-strontium hexaferrite permanent magnet
Authors: Gunanto Y E , Izaak M P , Sitompul H , Adi W A 
Published: March 2021

Abstract
This paper describes the effect of the substitution of Nd3+ ions in Barium-Strontium Hexaferrite (Ba0.6Sr0.4)1-xNdxFe12O19 with x = 0.01, 0.03 and 0.05, on the energy of the product. All samples were made from raw materials of barium (II) carbonate, strontium (II) carbonate, neodymium (III) oxide, and iron (III) oxide which each have a purity of > 99% which was processed by the solid-state reaction method using high energy milling with a rotating speed of 750 rpm.The crystal structure and phase formed are characterized using an X-ray diffractometer. Scanning electron microscopy is used for surface morphology analysis and permagraph is used for hysteresis characterization so that the product energy can be calculated. X-ray diffraction analysis showed that all phase samples have an orthorhombic structure and space group P nma. Surface morphology is almost homogeneous with heterogeneous shapes and the average particle size ranges from 200-800 nm. The maximum product energy obtained is 165.4kGOe in the sample x = 0.05.
Space group and morphology evolution of nanosized Nd(x)Sr(1-x)MnO3 manganite
Authors: Dharmayanti A M R , Munazat D R , Razaq D S , Kurniawan B , Mustaghfiroh Q , Nanto D , Handoko D 
Published: March 2021

Abstract
Polycrystalline series sample of Nd(x)Sr(1-x)MnO3 (x = 0.3; 0.7 and 0.9) has been prepared with sol-gel method. Refinement result from X-ray diffractometer shows that the sample are crystallize in the same orthorhombic structure with different space group of Imma and Pnma. Scanning Electron Microscope result also indicated that the different amount of substitution modified the grain size and both particle and crystallite size. After all, Nd0.7Sr0.3MnO3 has the largest cell volume followed by the largest grain and crystallite size compared to other two samples. Therefore, each different amount of substitution into the sample will give different impact and further investigation were needed to explore its relation to the physical properties.
Effect Of Mn On Structure And Corrosion Properties Of Co-Cr-Mo Alloys in Simulated Body Solutions
Authors: Qonita Aliya , Eka Perkasa Daniel , Soegijono Bambang 
Published: March 2021

Abstract
Metal alloys applied as biomedical materials have been developed for decade, due to the need for devices implanted into the human body. One of them is a cobalt-based alloy which commonly used as an orthopedic implant for total hip replacement. The biocompatibility properties of CoCrMo alloys make these alloys superior to corrosive resistance when making direct contact with the biological environment of the body where Simulated Body Fluid (SBF) solution is a solution often used to test its compatibility. The presence of manganese elements in CoCrMo Alloy and influence of heat treatment at temperature 700 oC for 65 hours were characterized by using X ray diffraction and Potentiostat. The structure and corrosion behavior in Simulated Body Fluid were discussed. The results show different crystal parameter and corrosion behavior observed. It concludes that, heat treatment and the presence of Mn affect the signicantly on the properties of CoCrMo Alloy.
Preliminary Study on the Use of Optical Fiber to Detect Borax Content in Meat
Authors: Yunianto Mohtar , Putri Andaresta Dita , Anwar Fuad , Endah Saraswati Teguh 
Published: March 2021

Abstract
A preliminary study has been conducted to detect the presence of borax in meat using a optical fiber sensor. The study was conducted in 2 stages, the first stage was a test using a UV-Vis spectrometer which was used as reference data to test the presence of borax in meat with variations in the borax mass of 0.1 gr, 0.2 gr and 0.3 gr mixed with each 40 gr of beef, while the next stage is to use an optical fiber sensor that has been made where the results of testing are compared with the results of the first stage. The results obtained in the initial stage are more and more borax content in the meat showing the absorbance value increases at a wavelength of 419 nm with an R2 value of 0.93. In the second stage using an optical fiber sensor, the results of transmittance values obtained at 419 nm wavelength decreased linearly with R2 values of 0.99, the transmittance value is inversely proportional to the absorbance value. This shows that a fiber optic sensor made has the potential to be used as detection for borax content in meat.
DECY-13 cyclotron equilibrium orbit verification using CYCLONE
Authors: Mulyani E , Taufik  , Darmawan R S , Kudus I A , Diah F I 
Published: March 2021

Abstract
A cyclotron is a machine that accelerates a charged particle in a circular trajectory using electric and magnetic fields. The technical development of 13 MeV cyclotron in PSTA (Pusat Sains dan Teknologi Akselerator) BATAN was started in 2010 which eventually will be used for radioisotope production. A cyclotron consists of various technologies such as an electromagnetic, RF (Radio Frequency), ion source, and vacuum systems. Among them, the electromagnetic creates a magnetic field for particles to accelerate in a stable circular orbit. A particle within a uniform magnetic field moves along a closed trajectory, and that is called an equilibrium orbit. The stability of particle acceleration refers to the movement along the equilibrium orbit with oscillation. This paper deals with the equilibrium orbit verification using CYCLONE. We calculated and analyzed the magnetic and electric fields using Opera, then used them as input data in CYCLONE. The CYCLONE analysis provides several beam parameters such as beam energy, tune diagram, and beam trajectory. The analysis result shows that the beam was accelerated until the desired energy (13 MeV).
Mapping and Analysis Burned Area Based on LANDSAT 8 OLI/TIRS and Hotspots Data in Palangkaraya of Central Kalimantan Province - Indonesia
Authors: Eko Cahyono Bowo , Fibyana Vica , Tjahjo Nugroho Agung , Subekti Agus 
Published: March 2021

Abstract
Indonesia experienced with big forest fire every year especially within dry season. Palangkaraya City of Central Kalimantan province is the most prone area with fire. It was reported that Palangkaraya had the highest risk of fire in 2019 which caused smog that disrupts people breathing and their daily activities. Indonesian government is paying a great attention to manage and suppress the fire. People are encouraged to provide information of burning location, responsible company and burned area in the incident. This study determined burned area in Palangkaraya using Normalized Burned Ratio (NBR) method and the results were validated with hotspots data acquired from LAPAN website. The results showed that 64.24% burned area is classified as low severity and only 1.04% of burned area is classified as high severity. The remaining area with 31.84% categorized in moderate low severity and 2.88% categorized in moderate high severity. The validation result showed that 100%of burned area is confirmed valid with the occurring hotspots.
Railway Vibration Level in Semarang City
Authors: Margiantono A. , Setijo H. , Setiawati E. 
Published: March 2021

Abstract
Increased train traffic in the city of Semarang caused an increase in vibration exposure to residents and buildings that are around the railroad. Train vibrations have a large influence on comfort, human health and building structures. The location of this research data collection in three places, namely Bulu Lor Settlement, Tawang Station area and Tlogomulyo Village, the reason the location was chosen is because the route is the busiest route in the city of Semarang so it has a high vibration level. Vibration intersection (A) and vibration velocity (v) are measured when a train is passing using a Vibration level meter. The results showed that the Bulu Lor settlement at a distance of 15m from the highest intersection of the axle road was 29.27 microns at a frequency of 12.5 Hz and the lowest was 4.45 microns at a frequency of 63 Hz. In the Tawang Station Area, the highest 25m distance is 20.38 microns at 12.5 Hz frequency and the lowest is 3.55 microns at 63Hz frequency, while in Tlogomulyo Kelurahan at 25m distance from the highest intersection of axles by 21.28 microns at 12, 5Hz and lowest 3.61 microns at 63Hz frequency. Referring to the results of this research, it can be concluded that all the values of the vibrational quantities are still below the standard level according to Kep-49 / MENLH / 11/1996, so that the vibrations of the passing trains do not disturb and do not damage the buildings at the three points of the research location.
Physical deterioration of soil and rice productivity in rural Java
Authors: Irawan S , Antriyandarti E 
Published: March 2021

Abstract
Soil degradation is one of the world’s most serious ecological and environmental problems affected agricultural productions. The agricultural sector defines land degradation as a process of decreasing land productivity that is temporary or permanent, characterized by a decrease in physical, chemical, and biological properties. This study aims to investigate the impact physical deterioration of which occurs in the form of structure fertilizer application on rice productivity. This study applied Autoregressive model to analyse the primary data collected from 4 main rice producer areas in Central Java and East Java, namely Cilacap, Grobogan, Lamongan and Jember. The results show that previous chemical fertilizer use has negative impacts on rice productivity. Inorganic chemical fertilizers have an important role in increasing productivity, but at the same time the uncontrolled use of it is one of the causes of the decline in the quality of biological, physical, and chemical fertility of the soil.
Quantitative Assessment of NPP Changes in the Yellow River Source Area from 2001 to 2017
Authors: Rong Tang , Long Lin Hui 
Published: March 2021

Abstract
It is of great significance to quantitatively evaluate the ecological degradation and restoration of the Yellow River source area from 2001 to 2017. Net primary productivity (NPP) is the core indicator used to indicate the health of terrestrial ecosystems. Based on the improved CASA (Carnegie-Ames-Stanford Approach) model and MOD17A3 NPP products, 174 measured sample sites were used to validate the NPP simulation results, select the model with higher accuracy as the actual NPP simulation, and using Theil-Sen median trend analysis and Mann-Kendall test to investigate the dynamics of NPP changes. The results are as follows: (1) the accuracy of the CASA model is higher than that of the MOD17A3 NPP product, and it is more suitable for the simulation of the actual NPP in the source area of the Yellow River; (2) the Yellow River Source region has shown a fluctuating upward trend in net primary productivity over the past 17 years, with 50% of the region showing a slight improvement, 36% showing a significant improvement, 13% showing a slight decline, and only 1% showing a significant decline, the average annual growth rate of NPP is 2.6 g C/yr-1. Compared with 2001, the net primary productivity in 2017 increased by 5.24×1012g C.
Efficient PFOS decomposition in an alkaline ultrasonic system
Authors: Gu Yurong , Jiang Chengchun , Dong Zijun , Xiao Yating 
Published: March 2021

Abstract
Perfluorooctane sulfonate (PFOS) has attracted increasing attention due to its global distribution, high chemical stability and environmental persistence. An alkaline ultrasonic system was explored and used for PFOS decomposition in this study. kobs of PFOS decomposition in the investigated system was 0.0196 min−1, which was remarkably efficient than that in sole ultrasonic system. eaq
− induced reductive decomposition and pyrolysis decomposition based on the collapse of cavitation bubble were found to be two main reasons contributing to PFOS decomposition. PFOS decomposition kinetics was boosted by increasing alkaline dosage and reaction temperature, but suppressed when increasing initial PFOS concentration.
Experimental Research on Dust Concentration Distribution Characteristics of Blast Furnace Cast House
Authors: Tianying Wang , Jingling Yang , Xiaohua Zhu , Hui Wang 
Published: March 2021

Abstract
This paper compares the temperature and dust concentration distribution of blast furnace cast house under different dust removal design conditions and external climate conditions by means of on-site sampling, field measurement and data analysis. It is found that the post temperature in closed design of cast house is 2.4°C lower than that in open design, but the dust concentration of the post of open design is 0.139 mg/m3, which is 1/10 of that of the closed design. Therefore, the open design is recommended. Different climatic conditions also have influence. It is suggested to close the main wind direction doors and windows when the outside wind speed is high to avoid turbulence.
Discussion on Related Factors of Air Pollution Based on Automatic Monitoring Data of Air Quality
Authors: Xia Li , Maolin Deng 
Published: March 2021

Abstract
Air pollution seriously affects people’s production and life. In order to explore the main factors affecting the air quality of Zhangye and evaluate the air quality, based on the national air quality automatic monitoring data, first, PM2.5, carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), and sulfur dioxide (SO2) are selected as the component factors of air pollution. Second, based on the fuzzy comprehensive evaluation method, the evaluation standard set and air quality pollution level are established. Finally, the time characteristics of each factor from 2016 to 2019 are analyzed. The results show that: the overall air quality of Zhangye is more serious in spring and winter, while it is more moderate in summer and autumn. PM 2.5 and O3 are the two key factors affecting its air quality; the air quality trend of Zhangye in recent years is good, and the overall air pollution level is below V2. The improvement of air quality depends on the effective control of all aspects, including human activities.
Research on environmental management of medical waste in the 14th Five-Year Plan
Authors: Shuangliu Liu , Liang Cheng , Zheng Zhang , Ya Tao , Mengyin Yao 
Published: March 2021

Abstract
Aiming to promote environmental management in the field of medical waste, based on the analysis of the current situation of national medical waste production and disposal, problems existing in the current system of concentrated disposal of medical wastes were identified, namely, the insufficient of centralized disposal capacity of medical waste in some areas, insufficient emergency disposal capacity reserve of medical waste, weakness of of medical waste supervision level and unperfect of technical standards. It is suggested to promote the environmental management of medical waste during the "14th Five-Year Plan" period by strengthening the centralized disposal capacity of medical waste in key cities, improving the disposal capacity of medical waste in rural and remote areas, speeding up the allocation of emergency disposal capacity of medical waste, and improving the environmental supervision capacity of medical waste.
Analysis of Temporal and Spatial Variation Characteristics of Air Quality in the Pearl River Delta during 2015-2019
Authors: Chuntao Huang , Qifeng Liao , Jifu Lu 
Published: March 2021

Abstract
Based on the history monitoring data of Air Quality Index (AQI) during 2015-2019, we conducted a contrastive analysis of the temporal and spatial variation characteristics of air quality in the Pearl River Delta. Results showed that the variation trends of AQI annual averages in the Pearl River Delta were basically the same. The AQI annual averages rose after decline and the variation curves were W-shaped. In the Pearl River Delta, Shenzhen and Huizhou enjoyed better air quality. In this region, AQI quarterly averages were high in autumn and winter but low in summer, and in a same year, the variation trends of the nine cities were basically the same. In autumn, the ozone concentration increased dramatically and therefore ozone became a major pollutant in ambient air. In winter, Guangzhou, Shenzhen and Dongguan saw a double-peak phenomenon in AQI hourly values, which rose at rush hours.
A two-stage robust optimization framework for land-water-environment nexus management
Authors: Chen Rui , Xu Zhongwen 
Published: March 2021

Abstract
On the premise of rational utilization of soil and water resources, systematic engineering method is widely considered to balance agriculture and ecology. Regular planning is carried out by the authority based on historical data and future expectation, however, uncertain environment cannot be ignored. Hence, we propose an adjusted dynamic two-stage robust optimization framework to explore comprehensive managerial insights of irrigative areas and forest expansion. Dynamic planning is adopted to reflect the long-period planning, and two-stage is to differ “wait-and-see” decision from “right-and-now” decision. Considering the whole system’ benefit, economic and ecological benefits are maximized and water scarcity, water/soil erosion penalties are minimized. To solve the proposed two-stage robust model, we propose two structural properties to obtain the global solution. After transformation, a C&CG algorithm is designed to calculate the proposed model.
Temporal and Spatial Succession Law of Abor Diversity in Xiaoxing’an Mountains
Authors: Li Jialin , Yang Jiao , Sun XueWei , Luo Jincheng , Qiu Hongbin , Li Lan 
Published: March 2021

Abstract
The national forest nature reserve in the Xiaoxing’anling area was studied. Based on the diversity of α and β, three forest types of grassland, birch forest, and larch forest were analyzed. Based on the diversity law of latitude gradient, the nature reserve was discussed in forest type. A difference in a diversity of different forest types was succession changes. A method based on quantitative evaluation of species conservation value was constructed. The community structure and species composition of nature reserves were systematically analyzed, and the conservation value of species and the conservation value of rare and endangered species were scientifically evaluated. The results showed that the Shannon Wiener index and Margalef index of grassland, birch forest, and larch forest showed a decreasing trend with the increase of latitude. Compared with the other four latitudes, the grassland, birch forest and larch forest of Dazhanhe Nature Reserve showed a decreasing trend from the north to south Jaccard index and Sorenson index, and the Cody index showed an increasing trend. The Jaccard index and the Sorenson index have peaks in friendly areas, and the species similarity is high, indicating that the friendly areas may be the interlaced areas of Xiaoxing’anling. The Shannon Wiener index and the Margalef index of the nature reserve from the early stage of succession to the middle and late succession increased continuously, reaching the maximum in the middle and late stages, and began to decline in the later stage of succession, which is consistent with the mid-specie.