bluuebunny/crossref_metadata_2025 huggingface dataset:
First-principles study of the impact of chemical doping and functional groups on the absorption spectra of graphene
Authors: Panneerselvam Iyyappa Rajan , Chakraborty Pranay , Nian Qiong , Lu Yongfeng , Liao Yiliang , Wang Yan
Published: December 2021

The rational design of the electronic band structures and the associated properties (e.g. optical) of advanced materials has remained challenging for crucial applications in optoelectronics, solar desalination, advanced manufacturing technologies, etc. In this work, using first-principles calculations, we studied the prospects of tuning the absorption spectra of graphene via defect engineering, i.e. chemical doping and oxidation. Our computational analysis shows that graphene functionalization with single hydroxyl and carboxylic acid fails to open a band gap in graphene. While single epoxide functionalization successfully opens a bandgap in graphene and increases absorptivity, however, other optical properties such as reflection, transmission, and dielectric constants are significantly altered. Boron and nitrogen dopants lead to p- and n-type doping, respectively, while fluorine dopants or a single-carbon atomic vacancy cannot create a significant bandgap in graphene. By rigorously considering the spin-polarization effect, we find that titanium, zirconium, and hafnium dopants can create a bandgap in graphene via an induced flat band around the Fermi level as well as the collapse of the Dirac cone. In addition, silicon, germanium, and tin dopants are also effective in improving the optical characteristics. Our work is important for future experimental work on graphene for laser and optical processing applications.
Characteristics of vapor based on complex networks in China
Authors: Feng Ai-Xia , Wang Qi-Guang , Zhang Shi-Xuan , Enomoto Takeshi , Gong Zhi-Qiang , Hu Ying-Ying , Feng Guo-Lin
Published: December 2021

The uneven spatial distribution of stations providing precipitable water vapor (PWV) observations in China hinders the effective use of these data in assimilation, nowcasting, and prediction. In this study, we proposed a complex network framework for exploring the topological structure and the collective behavior of PWV in the mainland of China. We used the Pearson correlation coefficient and transfer entropy to measure the linear and nonlinear relationships of PWV amongst different stations and to set up the undirected and directed complex networks, respectively. Our findings revealed the statistical and geographical distribution of the variables influencing PWV networks and identified the vapor information source and sink stations. Specifically, the findings showed that the statistical and spatial distributions of the undirected and directed complex vapor networks in terms of degree and distance were similar to each other (the common interaction mode for vapor stations and their locations). The betweenness results displayed different features. The largest betweenness ratio for directed networks tended to be larger than that of the undirected networks, implying that the transfer of directed PWV networks was more efficient than that of the undirected networks. The findings of this study are heuristic and will be useful for constructing the best strategy for the PWV data in applications such as vapor observational networks design and precipitation prediction.
Solutions and memory effect of fractional-order chaotic system: A review
Authors: He Shaobo , Wang Huihai , Sun Kehui
Published: December 2021

Fractional calculus is a 300 years topic, which has been introduced to real physics systems modeling and engineering applications. In the last few decades, fractional-order nonlinear chaotic systems have been widely investigated. Firstly, the most used methods to solve fractional-order chaotic systems are reviewed. Characteristics and memory effect in those method are summarized. Then we discuss the memory effect in the fractional-order chaotic systems through the fractional-order calculus and numerical solution algorithms. It shows that the integer-order derivative has full memory effect, while the fractional-order derivative has nonideal memory effect due to the kernel function. Memory loss and short memory are discussed. Finally, applications of the fractional-order chaotic systems regarding the memory effects are investigated. The work summarized in this manuscript provides reference value for the applied scientists and engineering community of fractional-order nonlinear chaotic systems.
Bilge System Design on 500 GT Ferry for Bulukumba–Selayar Route
Authors: Pawara M U , Setiawan W , Ikhwani R J , Alamsyah  , Wulandari A I , Suardi  , Nugraha A A M , Hidayat T , Ansori M I , Mahmuddin F
Published: December 2021

A piping system is the main part of a system that connects the point where the fluid is stored to the point of accessing the pipe. Both pipe strength and pump capacity must be carefully considered because the safety of a ship will depend on the piping arrangement as well as on other ship equipment. The main function of the bilge pipe system is the drainage system in case of flooding in the compartment due to grounding or collision. Another function is the drainage system in the event of leaks on the welding root, condensation on the side shell leaks on the piping system (particularly in the engine room), and discharge water due to water-splash over the hatch. This study aimed to design a bilge piping system design using Autopipe Software with ASME B31.3 standard for the piping process. The design phase of the system is collecting data, then determining the load case. After that, selecting components needed for the construction of the system. The following step, making 3-dimensional modeling on Autopipe by entering input based on the determining components. Finally, validating the model, and proceed with the running model according to the specified load case. The result of the running model is the pipe stress level which is described in the stress code in the Autopipe. The final results are 3-dimensional drawings of the system and the number of components needed for constructing the system under Indonesian Classification Bureau (BKI) rules and ASME B31.3 standards for the piping process.
Cocoa plantation carbon stock at different years after planting (5,10,15) in Tomoni Beringin Jaya Village, East Luwu, South Sulawesi, Indonesia
Authors: Nahdia  , Paembonan S A , Nasaruddin
Published: December 2021

This study aimed to determine cocoa carbon stocks based on the conditions of cocoa plantations in Tomoni Beringin Jaya Village, East Luwu, South Sulawesi, Indonesia. Carbon stocks were estimated from aboveground and belowground biomass using an allometric methodology. Sample sites were cocoa plantations; sampling intensity was 30% of the land planted with cocoa for 5 years (n = 214), 10 years (n=229) and 15 years (n=329), soil sampling disturb (measure soil organic carbon), un disturb (measure bulk soil bulk density) and soil bulk density at depth 0-10 cm and 10-20 cm. Carbon stock cocoa aboveground biomass at the age of 5 years (M45) was 1.89 ton C ha-1 and belowground biomass was 0.56 ton C ha-1 with proportion 77.19%:22.81%. Carbon stock cocoa aboveground biomass at the age of 10 year (BR25) was 3.66 ton C ha-1 and belowground biomass 1.01 ton C ha-1 with a proportion 78.37%:21.63%. Carbon stock cocoa aboveground biomass at 15 year (BR25) was 4.58 ton C ha-1 and belowground biomass of 1.21 ton C ha-1 with a proportion 79.07%:20.93%. Cocoa carbon stock at 5 year, 10 year, and 15 year respectively increased, nevertheless mean annual carbon stock cocoa decreased in 5 years cocoa aboveground biomass was 0.37 ton C ha-1 and belowground biomass 0.11 tonCa-1. Carbon stock cocoa 10 year aboveground biomass 0.36 ton C ha-1 and belowground biomass 0.10 ton C ha-1. Carbon stock cocoa 15 year aboveground biomass 0.30 ton C ha-1 and belowground biomass 0.08 ton C ha-1. Soil organic carbon showed dynamic under different year cocoa plantation. Soil organic carbon in cocoa plantation age 5 year was 0.031 tonCha-1, cocoa plantation age 10 year was 0.034 ton C ha-1, and cocoa plantation age 15 year was 0.043 ton C ha-1.
Influence of Number of Collisions Towards Asphalt Emulsion Mixture Stability Using Marshall Method (SNI 06-2489-1991)
Authors: Irianto  , Tumpu M. , Mabui D.S. , Mansyur
Published: December 2021

The development of road construction in Indonesia recently increased. This resulted in demand of asphalt, which is one of the materials used in the pavement mix has also increased. Aspalt emulsion in Indonesia have been applied, but only to the adhesive layer and the absorption layer. The Public Works Department of the Directorate General Bina Marga has issued several guidelines to guide the implementation of cold mix asphalt work. The use of emulsion asphalt mixture technology which has a low temperature will reduce emissions, reduce the amount of energy consumption, and avoid oxidation. This study aims to analyze the value of the optimum asphalt content (KAO) mixture of emulsion asphalt CSS-1h and to analyze the effect of the number of collisions on the stability of the emulsion asphalt mixture. The results show that based on the relationship between the emulsion asphalt content and all Marshall and volumetric parameters, the optimum residual asphalt content is obtained. The emulsion is 5.5%. The impact of the collision on the stability value increases with the number of collisions. This test results in stability values of 1223.5 kg, 1373 kg and 1401.1 kg for normal specimens while for immersed test objects the remaining stability values are 51.7 kg, 59 kg, 68.2 kg. Based on the values obtained, this test is declared to meet the specifications for the cold mix emulsion asphalt.
The effect of raw material composition of mixed carbonized canary shell and coal bio briquettes on caloric value
Authors: Widodo S , Asmiani N , Jafar N , Artiningsih A , Nurhawaisyah S R , Harwan  , Chalik C A , Thamrin M. , Husain J R
Published: December 2021

The fuel consumption rate rises and is expected to increase continuously, causing fuel supplies to be depleted and this condition forces the community to find alternative sources of fuel such as bio-briquettes. The waste of canary shells is widespread in Indonesia and can be used as an alternative energy source of bio-briquette making. There is a need for study on the influence of raw materials bio-briquette mixture of coal and canary shells against the value of calories produced. Bio-briquette making in this study have been done using canary shell and coal with a composition: (250 gr coal/canary shell: 12.5 tapioca starch: 50 ml water). Before briquette making, the canary shell samples are pirolysed and a grain-size reduction is performed on both of coal and canary shells. Canary shell and coal bio-briquettes are made with four variations (types). The types of bio briquette are: type I of bio-briquette with a composition of 250 gr (coal) + 12.5 gr (tapioca starch) + 50 ml (water). Type II of bio-briquette with a composition of 250 gr (canary shell) + 12.5 gr (tapioca starch) + 50 ml (water). Type III of bio-briquette with a composition of 62.5 gr canary shell + 62.5 gr coal + 12.5 gr (tapioca starch) + 50 ml (water). Bio-briquette type IV consist of 93.75 gr (canary shell) + 31.25 (coal) + 12.5 gr (tapioca starch) + 50 ml (water). After preparation, all bio briquettes are analyzed to determine the caloric value. The results of the study shows bio-briquette type I has a caloric value of 5,539 kcal/g, bio-briquette type II produces the highest calorie value of 6,354 kcal/g, and bio-briquette type III is 6,020 kcal/g. Further more bio-briquette Type IV indicate caloric value of 6,096 kcal/g. Bio-briquette type IV is the most recommended in the utilization because of the goal of this study is to use canary shell as an alternative fuel.
Economic Feasibility of a Small-Scale Wind Turbine in Coastal Area of South Sulawesi
Authors: Mahmuddin F , Puspitasari N , Pawara M U
Published: December 2021

To evaluate the exploitation potential of wind energy in the coastal area of South Sulawesi, Indonesia, an investigation on the economic feasibility of this project was performed. A 300-watt horizontal wind turbine was used as an example installed turbine. The wind speed range of 4-7 m/s which was the wind speed data in the coastal area of South Sulawesi was computed. The main economic analysis method employed was Capital Budgeting Analysis (CBA) method. In this method, 4 (four) indicators were used to evaluate the feasibility of the project which are payback period (PBP), net present value (NPV), internal rate of return (IRR), and benefit-cost ratio (BCR). A visual basic computer program based on the CBA method was also developed to make the computation more convenient. From the study, it was found that the wind speed range of 4-6 m/s resulted in a non-feasibility project while the highest wind speed (7 m/s) was found to be quite strong to make the project feasible.
Development of Real-Time Monitoring System for an Off-Grid Photovoltaic System
Authors: Sesa M , Mahmuddin F
Published: December 2021

In operating a photovoltaic system, it is required to employ hardware and software systems to monitor the parameter of the results of the solar panel conversion. Usually, monitoring the photovoltaic system is done by manual gauges and recording the measured results manually which would require a human hand. The present research designed and developed a real-time monitoring system for an off-grid photovoltaic system that could monitor the photovoltaic system performance automatically. The monitoring system design has 2 (two) subsystems. The first subsystem is a hardware system in the form of an electronic data logger system equipped with an SD card. This allowed data to be recorded on an SD card. The second sub-system is a software design developed using Microsoft in Visual Basic. The hardware and software were connected to monitor the photovoltaic results and recorded the obtained data in an SD card for further analysis.
Strategic Planning as a Mediation of The Influence of Organizational Climate and Competence to Competitive Advantage of Private Higher Education
Authors: Susanto A B , Kurniaty  , Purnamie T , Kapriani
Published: December 2021

In resource-based learning (RBV) emphasizing the improvement of the competitive advantage derived from the organization’s strategic resources This research is designed to support and develop models of competitive advantage that are appropriate for private universities based on their own resources. Data in this study were collected using a questionnaire for 9 months. The population in this study are universities in Indonesia. The sampling technique using purposive sampling. The results of the study show that the advantages possessed by the existing tertiary institutions differ from each other depending on the competencies of each of the tertiary institutions.
Rare Earth Elements Distribution in Weathered Volcanic Rock from Mamuju Area, West Sulawesi
Authors: Ritonga R , Maulana A , Tonggiroh A
Published: December 2021

The study on the distribution of rare earth elements (REE) was carried out from bedrock and its weathering profile at North Botteng Village, Simboro District and Kelapa Tujuh Village, Mamuju District, Mamuju Regency, West Sulawesi. This study aims to determine the potential and distribution of REE in the bedrock and its weathering profile and to identify the REE-bearing bedrock type. In addition, the relationship between REE and Zr element as one of REE associated elements is also discussed. The analytical method used include petrographic observations to identify the REE-bearing host rock and the ICP-MS (Inductively Coupled Plasma Mass Spectrometry) method to determine the REE content. Samples were taken from drilled hole samples in three different locations and classified into three groups, namely Group 1 (K-01 drill hole sample) and Group 2 (K-62 drill hole sample) from Kelapa Tujuh while Group 3 taken from the P-05 drill hole sample from North Botteng Village. Petrographic observations on the bedrock show that the REE are hosted by phonolitic leucitite composed of mainly leucite as phenocryst set in K-feldspar, plagioclase, pyroxene and opaque groundmass. REE content (expressed as TRE2O3 or total rare earth oxides) show a high concentration values ranging from 2000 - 6400 ppm and display variations enrichment in depth. The highest total REE content in Group 1 found in samples from 9 - 11 meters depth, which is 4600 ppm, while in Group 2 the highest concentration is from 4 - 5 meters depth with a total REE value of 2380 ppm and in Group 3 the highest value of REE content encountered at a depth of 6 - 7 meters, which is 6400 ppm. Zr content in Group 1 samples shows value range between 1780 - 2870 ppm whereas in Group 2 ranges from 1670 - 2380 ppm with the highest Zr concentration at a depth of 4 meters while in Group 3 the Zr content show values ranging from 2100 ppm - 4480 ppm with the highest concentration encountered a depth of 11 meters. The study results suggest that the relationship between REE and Zr element in Group 2 samples showed a positive relationship. Meanwhile, the Group 1 and 3 samples show a varied relationship. The REE concentration is controlled by elevation, in which areas with higher REE concentrations are encountered at elevations above 359 meter above sea level (masl) while low REE content concentrates in areas with elevations below 365 masl. REE enrichment is caused by weathering process that occurs on phonolitic leucite in the study area.
Study of Improving Soil Using Permit, Corn Ash and Sodium Silicate
Authors: Erwanto W , Parea. R. R , Ermitha. A
Published: December 2021

Soil that has low bearing capacity has a bad impact on the construction that is built on it as a result of which the building is easily damaged such as lifting the foundation on the building and causing cracks and shifting on the road. This research uses experimental laboratory methods. Soil samples used were taken from Lembang Tondon Siba’ta, Tondon District. Corn cobs were taken from Sa’dan Marante, Sodium silicate is obtained from chemical figures and palm fiber taken from Buntu Tagari and then tested for soil physical characteristics and soil bearing capacity in soil samples with a mixture of sodium silicate, corncob ash, palm fiber and soil without mixture. know the bearing capacity of the soil. The results of the research on stabilized soil by adding 0.2% palm fiber, 2% corncob ash and 3% sodium silicate obtained an increase in soil bearing capacity of 9.73% from the original soil and the addition of 0.2% palm fiber, 4% corncob ash and 3% sodium silicate.
Slum Handling Strategy Based On Community Social Economic Characteristics In The Slum Area In Bantaeng Sub-District, Bantaeng District, South Sulawesi
Authors: Budianto A , Wikantari R , Rahmadanih
Published: December 2021

Bantaeng District is one of the sub-districts in Bantaeng Regency, South Sulawesi Province, with a slum settlement problem. The increase in slum areas between 2014-2019 by 132.58 hectares shows the need for more effective treatment, which focuses on improving social and economic aspects to prevent the emergence of new slum settlements. This study aims to identify the socio-economic characteristics of the community in the slum area and formulate a slum management strategy. The results showed that, in general, the socio-economic characteristics of the people in the slum areas were shallow, including the level of education, most of whom only graduated from elementary school, work as laborers and farmers, and income ranged from Rp. 800,000 - Rp. 1,400,000 per month, with most of the land they occupy without ownership documents or are illegal. However, there are several better socio-economic conditions, such as the head of the family mostly still productive, the density of occupancy, which is mostly still above 7m2, adequate drinking water and sanitation facilities, and ownership of mostly self-owned buildings. Strategies that can be implemented are to encourage the improvement of the socio-economic quality of the community, involve the community in slum handling actions, and make the slum eradication program a priority program of the regional government.
The influence of intrusion on change characteristic of coal in Mallawa Formation of South Sulawesi Province
Authors: Anshariah A , Imran M , Widodo S , Irvan UR
Published: December 2021

Coal that is deposited in the same depositional environment, age, and formation will usually have the same characteristics. However, the influence of geological conditions in an area can cause differences in the characteristics of coal in the same formation. This study aims to analyze geological factors that can affect differences in the characteristics of coal in the same depositional environment, age and formation. The study was conducted at three different locations, namely Mallawa District, Maros Regency; Lanne District, Pangkep Regency; and Massenrengpulu Region, Bone Regency. The coal sampling method in the study area uses the channel sampling method (ply by ply) which represents the bottom, middle and top coal seams. The results of the proximate analysis of coal in the Mallawa District Maros Regency showed an average moisture content of 7.78%, an average ash content of 39.99%, volatile matter 32.85%, and fixed carbon 19.39%. While in the area of Lanne District, Pangkep Regency shows an average moisture content of 9.65%, an average ash content of 40.41%, volatile matter 33.80%, and fixed carbon 16.16%. The results of proximate analysis in the Massenrengpulu area of Pangkep Regency showed an average moisture content of 3.86%, an average ash content of 23.16%, volatile matter 35.53%, and fixed carbon 37.46%. Coal from Mallawa and Lanne District has relatively the same characteristics, while the Massenrengpulu coal has lower moisture and ash content, and higher fixed carbon caused by the intrusion of igneous rocks in the area which causes the coal maturation process to be faster than the other two regions.
Effect compressive strength and split tensile strength of concrete using aggregate from Tana Toraja district with fly ash substitution
Authors: Wong I L K
Published: December 2021

Development in Indonesia is increasing day by day. This has resulted in the construction sector from year to year experiencing a lot of progress both in terms of planning/design and in terms of updating the construction methods used. Tana Toraja regency is precise in Saluputti districts. the Maulu river is a source of a lot of coarse and fine aggregates that can be used as a material for mixing concrete. Because this area is the meeting point between the largest rivers. especially in Tana Toraja. Therefore. in this study. coarse and fine aggregates from Tana Toraja. Saluputti district are used as research objects with fly ash as an additional ingredient. The research objective was to determine the effect of fly ash substitution on compressive strength and split tensile in concrete with Tana Toraja aggregate and to determine the characteristics of the concrete produced using the aggregate from Tana Toraja with fly ash substitution. The research method is a sample testing method. in which 72 samples were tested consisting of 36 samples of compressive strength and 36 samples of split tensile strength. The test was carried out at the Concrete Structure and Material Laboratory. Department of Civil Engineering. Universitas Kristen Indonesia Paulus – Makassar South Sulawesi. The results showed that the use of fly ash as a partial substitute for cement would reduce the strength of concrete compared to concrete without the use of fly ash. The greater the level of fly ash given. the strength of the concrete will be reduced by using the aggregate from Tana Toraja district.
Commercial Advantages of Soybeans Commodities South Sulawesi
Authors: Gaffar N F , Mahyuddin  , Tenriawaru A N
Published: December 2021

The first step towards an efficient agriculture is the determination of superior commodities that are sought in order to obtain commodities that have a comparative advantage. The purpose of this study is to analyze the comparative advantages of soybean commodity in the production center areas, namely Bone Regency and Takalar Regency, South Sulawesi. The location selection was done purposively with the consideration that Bone Regency and Takalar Regency were one of the soybean production centers in South Sulawesi. The research method is quantitative analysis using Location Quotient Analysis (Location Quotient: LQ). Based on the results of the study, using the Location Quotient Analysis (LQ) in accordance with the second objective of analyzing the comparative advantage of soybean commodities in the production centers of Bone and Takalar Districts shows LQ <1. Where these results indicate that soybeans in Bone and Takalar Districts are categorized as the nonbase sector or can also be said to have no comparative advantage because it produces LQ <1, namely for Bone District (0.80688338) and Takalar District (0.7745655). It is said to have no comparative advantage when compared to rice and corn.
Dimensional Analysis of Compound Section in The Regulate Section Channel Model for Maintenance Main Channel
Authors: Rohani I , Paroka D , Thaha M A , Hatta M P
Published: December 2021

A dimensionless number is used to express the relationship between parameters and is used to describe the research results. Commonly used dimensional analysis methods are the Basic Echelon method, the Buckingham method, the Rayleight method, the Stepwise method and the Langhaar method. The compound section in the regulated section channel model aims to make the section convenient to the flow existing discharge at tidal conditions, in sediment flushing. In this study using the Buckingham’s method of dimensional analysis to determine the weight equation for the flushing sediment (w) and the variables that have been scaled on the flume, W = • (B, B*, h, h*, ⊗h, t, V, Q, g, W,)w,)S), where B is the width of the river (cm), B* is the width of the Flushing section (cm), h is the height of the water level (cm), h* is the height of the flushing section (cm), ®h is the difference in water level (cm), t is the tidal time period (s), V is the flow velocity (cm/s), Q is the water discharge (cm3/s), g is the gravity (cm/s2), )S is the mass density of the sediment (gr/cm3), )w is the density of the water mass (gr/cm3). From the analysis results obtained equations =

B
*

B

.

h
*

h

.

Δ
h

h

.

v

g
t

.

Q

g

h
2

t

.

ρ
s

h
3

. Where w is the weight of the flushing sediment (gr),

B
*

B

is the ratio of the design cross-sectional width to the width of the estuary,

h
*

h

is the ratio of the flushing cross-sectional height to the water level,

Δ
h

h

is the ratio of the height water level to water depth,

v

g
t

is the velocity of falling sediment,

Q

g

h
2

t

is the discharge of sediment flushing, ρ
s

h
3 is the hydrostatic pressure.
The Study of Port Capacity Development Plan In Wosu
Authors: Hatta M P , Karamma R , Fazry H
Published: December 2021

The development of the Wosu Port will be able to stimulate inter-regional trade and reduce logistics costs because goods from other islands to be marketed in Morowali Regency against agricultural goods from the hinterland of Wosu Bungku Barat Port can be sent directly to other islands. For this reason, data collection is needed so that it can be analysed for capacity development of Wosu Port. The purpose of this study is to determine the layout (lay out) of the Wosu Morowali Port and shipping lanes that are adjusted to the size of the draft ship plan, to determine the type and dimensions of the dock that are in accordance with the conditions in the Wosu area. The method used in this research is to conduct a field survey to collect primary data and secondary data obtained from websites that are processed using Ms Excel, Autocad, Ocean Data View. By knowing the topography, hydro-oceanography and economic data, alternative port development can be determined. This research produces topographic-bathymetric maps, water zoning maps, land and water DLKr / DLkp designs, short-term port development layouts where the planned jetty is a jetty which has a trestle length = 70 m and a width = 8 m having a pier floor elevation = 2 m and in areas with a depth of 10-15 m to allow general passenger / cargo ships (GT / DWT 500-1000 Ton) to dock.
Enhanced Perovskite Solar Cell Performance by Adding Magnesium Acetate Using Two-Step Spin-Coating Method
Authors: Yusra D A , Mufti N , Muyasaroh A F , Latifah E
Published: December 2021

The poor stability of perovskite materials is a problem of concern in commercialization. In this study, we investigated the doping of magnesium cations (Mg2+) in PbI2 to improve the stability and efficiency of perovskite solar cells. The doping effect of Mg2+ can increase the crystallization rate. The perovskite film fabricated structure consists of ITO/TiO2/perovskite/CuO. The fabrication method used is a two-stage spin coating. The concentrations of MgAc2 were used 0, 0.75, 1, and 1.25 mg ml−1. The characterizations used are XRD (X-Ray Diffraction), UV-Vis, SEM-EDX. While the performance of solar cells is measured using a solar simulator. The XRD pattern shows that the sample has a crystal structure of MAPbI3, PbI2, and CuO phases. The MAPbI3 lattice parameter increased with increasing Mg acetate concentration. The grain size of the perovskite layer is between 5 - 15 μm, with a thickness of about 30 μm. The efficiency of perovskite solar cells increases with the increasing concentration of MgAc2.
Acid Value Reduction of Calophyllum inophyllum Oil by Oilseeds In situ Esterification Using Sulfuric Acid Catalyzed Methanol and Isopropyl Alcohol Mixture
Authors: Mufidah Nabilah Amirothul , Cahyani Anggun Dwi , Prabaningrum Nunung , Kusnanto
Published: December 2021

Non-edible oilseed can be used in biodiesel preparation as a low-cost feedstock. However, it contains a high free fatty acid or a high acid value, which causes a problematic biodiesel reaction. The investigation of acid value reduction of Calophyllum inophyllum oilseed by in situ esterification using sulfuric acid-catalyzed methanol and isopropyl alcohol has been conducted. Calophyllum inophyllum oil was extracted by n-hexane in the Soxhlet apparatus to determine the oil content. In situ esterification using methanol-isopropyl alcohol and the sulfuric acid as a catalyst was carried out in a reflux three-neck rounded bottom flask batch process to decrease free fatty acid or acid value. Four independent reaction variables, including the ratio of mixture volume to seed weight, the ratio of methanol to mixture volume, catalyst percentage, and reaction time, were varied. The experiments utilized by the response surface methodology with central composite design configuration to obtain the optimum conditions. The oil content of Calophyllum inophyllum oilseed extraction was 57.94% and an acid value was 90.38 mg KOH/g. The maximum esterified oil yield of 91.00% and 3.81 mg KOH/g minimum acid value were achieved in the optimum reaction conditions.
Study of Hybrid System for Optimization of Energy Source in Ut Island, Maluku
Authors: Aisyah Siti , Aditya Indra Ardhanayudha , Damanik Natalina
Published: December 2021

Eastern side of Indonesia has a group of scattered Islands and have a great distance from the main Island. Fossil fuels are the main option for meeting the needs of electrical energy in the outer Islands. But the availability of fossil fuels is very dependent on the weather and modes of transportation. In addition, fossil energy also causes emissions and environmental pollution, so efforts to diversify alternative energy by utilizing renewable energy are needed to meet energy needs. Ut Island, Maluku is one of the Islands which is not yet powered by utilities. In this paper, the HOMER software is used to determine the optimal hybrid power plant configuration from a techno-economic perspective by utilizing energy resources available on the Island. From the simulations that have been carried out wind speed has a significant influence on the optimal configuration of the PLH system. Load value affects the amount of NPC and COE. The greater the load is fulfilled, the higher the NPC. But contrary to NPC, COE value will decrease.
Correlation between Weather Variables and Electricity Demand
Authors: Aisyah Siti , Simaremare Arionmaro Asi
Published: December 2021

In the industrial era 4.0 as it is today, along with the increasing need for electrical energy, energy efficiency is an essential factor in achieving energy production cost efficiency. Efficiency will be achieved if electricity production can be adjusted to the customer’s electrical load. However, adjusting the electricity production poses a challenge, namely the difficulty of predicting the daily electricity load of customers. There are many factors that affect the electric load. One of the main factors is the weather. Therefore, this study focuses on the correlation of weather parameters on load demand. The weather parameters consist of temperature, rainfall, solar radiation, and wind speed. Case studies were conducted in Bali Island and Central Java Province. This paper looked for correlations between weather parameters with the load demand, especially in the island of Bali and Central Java Province.
Design and Analysis of a Solar-Powered DC Irrigation System: A Case Study of a Shrimp Pond
Authors: Faizal Ahmad , Kunaifi  , Miefthawati Nanda Putri , Ullah Aulia , Anjarjati Wahyu
Published: December 2021

In this paper, a new approach for supplying water to shrimp production ponds in Purworejo, Indonesia, is proposed. The paper covers the design of a solar-powered DC water pump system (SWPS), system performance analysis, and economic analysis by comparing it with the existing fossil-fuel-powered pumps. The mathematical approach for the designing process is shown and Lorents Compass alternative tool is introduced. By taking into consideration the daily water demand of 50 m3/day, the annual-averaged local solar irradiation of 4.7 kWh/m2 per day, and the available components in the market, an SWPS in Purworejo would comprise a 1200 Wp PV panel and a 600 W DC pump submerged in a borehole in the seashore. The SWPS would be able to meet the daily water demand with small seasonal variations. The financial analysis shows high feasibility to install SWPS in Purworejo with a 1,6 years simple payback period, which is very short. The SWPS would provide more than 20 years of free energy for the farmers to draw seawater to the pond each day when the sun shines. It can provide not only environmental and social benefits but also significant economic advantages, both at the farm and the national levels.
Study of Several Types of Lithium-polymer Batteries With 3s Battery Management System
Authors: Karlina F H , Sunarno  , Waruwu M M , Wijaya R
Published: December 2021

Lithium batteries have been identified as one of the most promising energy conversion and storage devices because of their high energy density, safety, and long cycling life. Lithium-polymer batteries have been widely used in various applications ranging from electric vehicles to mobile devices. The purpose of this study was to determine the best type of lithium-polymer and VRLA batteries in the review of the balance of battery life timeout comparison for a predetermined load. Each battery has a different actual balance and theoretical comparison value. The best balance value is close to 1. The best balance comparison after the experiment was a LiPo battery type with a balance value of 0.77 R158F076A7 BMS 3s, then VRLA with a balance of 0.67, and the smallest balance is a LiPo GSE 18650 battery with a balance of 0.25. For both types of batteries with the same input parameters provided, the terminal voltage, current, and characteristics output of Lithium-polymer Li-Po GSE 18650. Batteries were found to be better than a lead-acid with a timeout of use that is 51.64 minutes.
Plasma-Ozone Treatment of Air Supply on Performance and Emissions of Diesel Engine
Authors: Insani Melati Nurul , Hayat Azwar , Amaliyah Novriany , Eka Putra Andi Erwin
Published: December 2021

In improving performance and reducing exhaust emissions in combustion engines, the addition of ozone to the air supplied in the combustion chamber was studied. In this research, ozone can be produced using plasma technology (plasma-ozone) which is a simple and eco-friendly technology. Plasma-ozone was generated using the Dielectric Barrier Discharge (DBD) method. Air is passed in plasma-ozone reactors at different voltages with an ozone variation of 3 mg, 12 mg, 15 mg and 18 mg is obtained. Ozone concentration was detected using an Ozone meter O3 Air Quality Detector and OPA-100 was used to determine exhaust emissions. The result showed that the addition of ozone to the air supply has no significant effect on brake power but is able to increase specific fuel consumption, increase cylinder pressure, shorten combustion processes, and reduce heat release values. The addition of ozone decreases the opacity of exhaust emissions in TV-1 diesel engines become more eco-friendly.
Simulation Analysis of the Pyrolysis Process for the Production of Syngas from Oil Palm Empty Fruit Bunch and Fiber
Authors: Nur Taufiq Bin , Kongnardi Justin
Published: December 2021

There have been many efforts to reduce the use of fossil fuels and reduce carbon dioxide emissions by using renewable energy (solar energy, wind energy, water energy, and energy obtained from biomass) as a substitute for fossil fuels. As one of the largest CPO producers globally, Indonesia produces 4 kilograms of dry biomass for every 1 kilogram of oil palm produced. The biomass conversion process into synthetic gas (syngas) can be carried out using the pyrolysis process. The syngas can be used as an alternative fuel for an internal combustion engine. This study aims to simulate the pyrolysis process to obtain syngas’ characteristics made from oil palm empty bunches (EFBs) and palm fiber. Around 4 kg EFB and 2 kg of fiber are used as pyrolysis raw materials. The Aspen Plus simulation was used to design and analyzed the pyrolysis flow processes. The results showed that the hot syngas produced at a working temperature of 450°C to 650°C was 1.475 kg/hr to 1.587 kg/hr. The cold syngas produced is 0.969 kg/hr to 1.407 kg/hr. The heating value of hot syngas is 10,348 kJ/kg to 14,213.55 kJ/kg, and cold syngas is 15,751.51 kJ/kg to 16,022.7 kJ/kg. Change in syngas composition between hot and cold syngas is due to the condensation process. The minimum condenser area required to produce cold syngas for 6 kg and 500 kg biomass pyrolysis raw material are 25.5 m2 and 632.2 m2, respectively.
Prediction of the monthly cost of energy usage by PEMFC at housing in North Sumatra Province, Indonesia
Authors: Nur Taufiq Bin , Harahap Mar’i Muhammad
Published: December 2021

The development of renewable energy is increasing nowadays. Besides, the development of energy conversion systems that can work at high efficiency also increases along with the decreasing availability of fossil energy. The fuel cell is an electrochemical device that converts chemical reaction energy directly into direct current electrical energy. The use of fuel cells as power generating in housing has also increased rapidly, especially in developed countries. This study aims to develop a model and simulation for the Polymer Exchange Membrane Fuel Cell (PEMFC) system with a working temperature of 165 °C) using Aspen Plus simulation. In this analysis, the model and simulation developed are used to predict the amount of fuel needed when used in housing as an electricity generator and obtain a monetary value for the monthly fuel procurement. The PEMFC system is designed to generate power up to 0.60 kW by consuming hydrogen fuel with a current density of 0.02 A/cm2. The hydrogen consumed by the PEMFC system is around 0.030 kg/hour, with a monthly cost of hydrogen consumption by the system is Rp. 2,052,000. Meanwhile, the monthly electricity from the national grid (PLN) bill costs around Rp. 569,261 (in the year 2019). In comparing the energy bill, at the moment, the fuel cost for PEMFC as a power generation system is much more expensive than PLN’s electricity consumption costs due to the high hydrogen fuel cost.
Preliminary Study on the Remaining Life Estimation Method for Research Reactor Tank Liner
Authors: Sukarno Diah Hidayanti , Aji Bintoro , Pramono Yudi
Published: December 2021

The reactor tank liner is one of the most crucial safety barriers in a research reactor as it retains the radioactive material released from the fuel during the accident condition. It also contains the primary coolant for fission heat removal. The integrity of the tank liner determines the service life of the research reactor. So far, the remaining life estimation of pressure vessels in nuclear power plants is more widely applied and established than that of the research reactor tank liner. Therefore, a study on the remaining life estimation method of the research reactor tank liner is needed to ensure the research reactor operation safety. This paper aims to preliminarily study several methods applied to estimate the remaining life of a research reactor tank liner. The preliminary study consists of a qualitative assessment and a quantitative assessment. The qualitative assessment aims to propose several techniques or methods applied in estimating the remaining life of the reactor tank liner. The quantitative assessment applies one of the remaining life estimation methods discussed in the previous assessment. Generally, the remaining life of the research reactor tank liner can be estimated using the theoretical method and the experimental method. The theoretical methods are applied by calculating the neutron fluence received by the tank liner or by analyzing the fracture mechanics using numerical modeling if the cracks or other defects exist. The calculation of atom displacement number (dpa), as a standard measure of the neutron-induced radiation damage of the materials, can support the neutron fluence calculation. The experimental method is conducted by measuring several parameters of the tank liner material, such as the corrosion rate or the mechanical properties. In the quantitative assessment, the remaining life estimation of the Kartini Reactor tank liner was performed by neutron fluence calculation method using MCNP6 computer code. The result shows that the maximum neutron fluence received by the tank wall is 2.950E+17 n/cm2 for 40 years operating period. By comparing the cumulative neutron fluence received for 40 years to the thermal neutron fluence limit value of 1.18E+23 n/cm2, the Kartini Reactor tank liner can still be used for the next 1.6E+07 operation years. The result of the quantitative assessment implicitly shows that the remaining life estimation of the tank liner needs to: 1) consider all defects experienced by the tank liner and all factors (e.g., thermal, radiation, chemical, cyclic loading) which affect the tank liner material condition, and 2) perform the combination of theoretical and experimental methods. For an open-pool type reactor, corrosion monitoring and corrosion rate measurement are essential to perform the remaining life assessment of the tank liner.
Paleobotany collections: fossil woods available at the Bandung Geological Museum
Authors: Mandang Y I , Andianto  , Oktariani H
Published: December 2021

Indonesia is a country which has plants species diversity. The form of ancient plants that grew in the past are recorded as fossil woods. Several fossil woods from regions in Indonesia were collected and became exhibition collections at the Bandung Geological Museum. These fossil woods on display requires biology identity to provide more information to visitors. Identification of species of fossil woods were carried out based on the anatomical features on the smoothed cross-section. Observations were carried out by a loop hand (a magnification of 10 times and a digital loop (with a magnification of 16 times). The fossil woods anatomy features observed included vessel cells, parenchyma cells, rays cells, and the presence of resin channels. The fossil specimen which had unclear anatomy features compared by detailed description of wood anatomy available at the library and collections of wood samples owned by the Xylarium Bogoriense. The fossil woods species are Canarioxylon sp., Terminalioxylon sp., Anisopteroxylon sp., Dipterocarpoxylon sp., Dryobalanoxylon sp., Hopenium/Hopeoxylon sp., Shoreoxylon sp., Kompassioxylon sp., and Xanthophyllum sp. The mostly fossil woods species resvectively belonging to the Dipterocarpaceae, Combretaceae, Polygalaceae, Burseraceae, and Leguminosae. The fossil woods member of Dipterocarpaceae family are conspicuously characterized with the presence of resin canals.
Primer design of D-loop region for wild population genetics of Rusa timorensis in Indonesia
Authors: Rianti P , Hutapea A L , Rahman D A , Santosa Y
Published: December 2021

Rusa timorensis (Javan deer) is endemic wildlife in Indonesia and is estimated at less than 10.000 individuals with continuously declining populations due to habitat loss and illegal hunting in the wild. This declining low population indicates a greater risk of extinction. Unfortunately, the genetic information of the wild Javan deer population for conservation management strategies still lacks data due to challenging sampling in the wild. Most recent studies were analysing the breeding populations outside Indonesia. Here, we propose the primer design of the D-loop genetic marker to determine the genetic population of wild Javan deer. We used metadata analysis of genetic sequences and new samples from five wild populations to design the specific primer of the D-loop region of the wild Javan deer in Indonesia. We used software, i.e.., Primer3 to design the primers, BLAST for specificity and Oligo Analyzer™ Tool for efficiency of the primer. The Annealing temperature optimisation started with pre-denaturation at 94 °C followed by 35 cycles of denaturation at 95°C; 51-56°C annealing for each one degree’s different per PCR treatment; and 72°C extensions. We successfully designed a specific primer (RL-3.1a) to amplify 235 bp of the D-loop region at 52°C annealing’s temperature.
Reproductive biology of the Rote Snake-necked Turtle Chelodina mccordi (Rhodin, 1994) in Oelsonbai Captivity, Kupang
Authors: Kayat  , Saragih G S
Published: December 2021

The Rote snake-necked turtle (Chelodina mccordiRhodin, 1994) or Kura-kura Leher Ular Rote is an endangered species endemic to Rote Island, East Nusa Tenggara. It is listed as Critically Endangered by the IUCN. However, based on surveys in recent years,C. mccordiwas presumed extinct in the wild. Ex-situ conservation is one alternative to conserveC. mccordi. The purpose of this paper is to describe the reproductive biology of the Rote snake-necked turtle in captivity. Three (one male and two female) C.mccordiwere observed in Oelsonbai captivity, Kupang, from 2009 to 2020 to obtain data on the species’ reproductive biology. The first mating behaviour was observed when the turtles were six years old. Hatches occurred two or three times a year, with clutch size varied from five to twenty eggs. Egg hatchability was 75-100 percent, with an incubation period of 76 to 102 days. Female size when mature straight-line carapace length (SCL) 178 mm, carapace width 145 mm, and plastron length 142 mm. Male size straight-line carapace length (SCL) 190 mm, carapace width 150 mm, and plastron length 143 mm.