bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilizing of CaO catalyst from chicken eggshells at several concentrations to produce biodiesel based on moringa seed oil
Authors: Hardi J , Ruslan  , Prismawiryanti  
Published: February 2021

AbstractChicken eggshells contain a high concentration of CaCO3compounds, which are potentially transformed to CaO by calcination method. CaO has been used as a heterogeneous catalyst for biodiesel or fatty acid methyl ester production from Moringa seed oil. The purpose of this study is to determine the percentage of CaO which produces the highest methyl ester mass fraction and to find out the characteristics of the biodiesel. Biodiesel was made through a transesterification reaction by using a CaO catalyst that has been calcined at 900°C for 2 hours. This study was conducted using a completely randomized design (CRD) with the independent variable in the form of CaO mass percentages consisting of 5 levels (1, 2, 3, 4, and 5%). CaO catalyst at 3% concentration resulted in a mass fraction of methyl ester of 57.1%. Characteristics of the biodiesel contained water content of 0.3%, acid number of 0.03 mg KOH/g, saponification number of 6.93 mg KOH/g, iodine number of 5.49 g iod/100g, cloud point of 18°C, and pour point of 16°C. Some of the characteristics have fulfilled the standardizations of ASTM and SNI.
Effects of washing method of nickel slag to the structural properties of composite nickel slag/laterite soil for high electromagnetic wave absorption performance
Authors: Heryanto  , Mahmud M , Fibiyanthy  , Rahmat R , Rahmi M H , Tahir D 
Published: February 2021

Abstract
Laterite soil (LS) doped with nickel slag (NS) for different solvent was successfully use to enhance the microwave absorption properties. First, NS/LS-01 is laterite soil doped with nickel slag for washed by using hydrogen chloride and second, NS/LS-02 for nickel slag washed by using sodium chloride. All samples are prepared by milling method at low frequency (10 Hz). X-ray diffraction (XRD) result revealed that the as polycrystalline of a cubic phase and diffraction spectra were dominated by magnetite (Fe3O4). X-ray peak broadening was analyzed to evaluate the structural properties. The quantitative analysis of structural properties in this studies are Scherrer, Williamson-Hall and Size strain plot method. Crystallite size (D), micro strain (ε), stress (σ) and energy density (u) were extracted from the peak line broadening. NS/LS-02 shows the smallest volume lattice, the energy density and the best reflection loss (RL) from the vector network analyzer (VNA). It is reveals the unit cell with high energy density strong relationship with microwave properties. In this study easy method to find the best correlation between structural and microwave properties.
Trend analysis of total rainfall events with light and heavy intensity for the 1976 – 2019 periode in Majene District – West Sulawesi
Authors: Roguna S , Alfiandy S 
Published: February 2021

AbstractThe increase of rain events due to climate change can affect local activities in several sectors such as agriculture, trade, infrastructure, etc, so climate information is importantly considered for operational sustainability. Therefore, this research is conducted to determine trend of changes in total rainy days and tendency of rain which refers to light rain <5 mm/day and heavy >30 mm/day every month in Majene based on Majene Meteorological Station data during 1976 – 2019 using linear regression method. Besides this research aims to provide information to related parties to consider policies as anticipatory and mitigating steps for natural phenomena to achieve effective activities. Results of analysis indicated a tendency of increasing trend in total of rainy days, the number of light and heavy rainy days in certain months. Based on rain posts, the increasing number of rainy days is dominantly followed by light rain events. This study informs that climate change has occurred in Majene, namely the increasing number of light rainy days. The information in this study can be used as knowledge to readers and consideration in certain policies, that the light rain happens a lot, but it cannot be denied that heavy rain will occur at any time unexpectedly.
Synthesis and material characterization of TiO2 nanoparticles doped with iron (Fe)
Authors: Gareso P L , Heryanto H , Sampebatu E C , Sampe N , Palentek V , Taba P , Juarlin E , Aryanto D 
Published: February 2021

Abstract
Titanium dioxide (TiO2) doped with iron (Fe) atom are investigated using X-Ray diffraction, field emission scanning electron microscopy (FESEM), and photocatalysts measurements. Fe-TiO2 nanoparticles with different concentration of iron were formed using the conventional co-precipitation technique from two different chemical solutions. The precursors of TiO2 were prepared using titanium tetrachloride (TiCl4) of 50 ml, and iron trichloride (FeCl3) was used as a dopant source. X-ray diffraction results show that diffraction pattern have two phases structures anatase and rutile phase structures where the intensity of the rutile structures are superior to that the anatase phase intensities. The results from FESEM micrograph indicate that the agglomerations were taken place, forming into clusters. Irradiation of ultraviolet (UV) with varying the time from 30 minutes to 120 minutes to the Fe-doped TiO2 nanoparticles using methylene blue shows that the absorption intensity reduces as time irradiation increased. The results indicate that the TiO2 nanoparticles doped with iron are suitable as photocatalysts.
The effect of the concentration of the stabilizer in the formation of a silver nanoparticle on the phenomenon of Surface Plasmon Resonance (SPR) as an active material for biosensor
Authors: Mahmudin L , Darwis D , Suharyadi E , Utomo A B S , Abraha K 
Published: February 2021

Abstract
It has been successfully synthesized silver nanoparticles by chemical reduction methods. Silver nitrate (AgNO3) is used as a metal precursor and trisodium citrate as a reducing agent with varying concentrations of the stabilizer PVA. The UV-Vis spectrometer shows that increasing the mass concentration of the stabilizer can sharpen the surface plasmon maximum absorption band and there is a shift in the maximum absorption band towards a larger wavelength. This shift occurred from a wavelength of 428.79 nm at a PVA concentration of 0.85 ppm shifted to a wavelength of 429.01 nm, 430.93 nm and 434.13 nm for each PVA concentration of 1.70 ppm, 2.55 ppm and 4.25 ppm. The observation results of the SPR phenomenon showed a shift in the SPR angle when a thin layer of silver as the active ingredient of the sensor was coated with silver nanoparticles. This addition also sharpens the reflectance value. The SPR angle shift and the increase in reflectance value are caused by changes in the surface plasmon wave constant, which becomes a reference that the SPR phenomenon by modifying the sensing surface using an additional layer of silver nanoparticles can increase its sensitivity.
Synthesis of TiO2-Ag composite through ultrasonic batch cleaning technique as a candidate for antifungal agent Phytophthora palmivora
Authors: Watoni A H , Yanti N A , Marlini S , Muzakkar M Z , Maulidiyah M , Irwan I , Arham Z , Nurdin M 
Published: February 2021

Abstract
In this work, TiO2-Ag composites have been synthesized through the Ultrasonic Batch Cleaning technique and applied as an antifungal candidate against Phytophthora palmivora. P. palmivora is a pod rot fungus on cacao plants. Physically, the successful synthesis of TiO2-Ag has been characterized by a change in the color of the precipitate from white to grey. This success was confirmed by Scanning Electron Microscopy (SEM) analysis, where the presence of Ag+ ions made the TiO2 surface more regular. The Ag+ ion was evenly distributed on the TiO2 surface and covers the large TiO2 particles. The results of EDX analysis have shown that the % composition of TiO2-Ag was 93.22%, each consisting of Ti of 50.37%, O of 37.57%, and Ag of 5.25%. Based on the antifungal activity test, TiO2-Ag has good antifungal activity against P.
palmivora. The minimum inhibitory level occurred at a concentration of 2.50%, while the minimum lethal rate occurred at a concentration of 4.88%.
Adsorption characteristics of copper ions using biocharcoal derived from nutmeg shell
Authors: Walanda D K , Napitupulu M , Irfan  
Published: February 2021

Abstract
The objective of this study was to characterize the parameter conditions such as optimum weight, contact time, pH, and concentration of the copper solution upon the absorption of biocharcoal derived from nutmeg shell. The concentration of copper ions was measured at a wavelength of 324.7 nm using an atomic absorption spectrophotometer (AAS). Results showed that the optimum adsorption of Cu(II) ions on the optimum weight of biocharcoal was 125 mg, the percentage of Cu(II) ions adsorption was 95.69%, and the weight of Cu(II) ions adsorbed was 11.48 mg/g. The optimum contact time was obtained at 60 minutes with the adsorption percentage of Cu(II) ions of 98.19%, in which the weight of adsorbed ions was 10.25 mg/g. The optimum pH was obtained at pH 7.0 with the adsorption percentage of Cu(II) ions was 99.95%, with the weight of adsorbed Cu(II) ions was 11.99 mg/g. The optimum concentration was obtained at 20 ppm with the adsorption percentage of Cu(II) ions was 99.75%, whereas the weight of the adsorbed Cu(II) ions was 7.99 mg/g. The maximum adsorption capacity of biocharcoal against Cu(II) ions using the Langmuir isotherm equation was 62.50 mg/g biocharcoal.
The amount and type of plastics in the Baiya Beach after the Palu Bay tsunami
Authors: Sulistiawati D , Safir M , Putra A E , Mansyur K , Rizal A , Serdiati N , Siampa T , Ya’la Z R 
Published: February 2021

Abstract
Plastic is a material that cannot naturally be decomposed. The increase in the amount of marine litter is influenced by currents, winds, tides and tsunamis at certain locations. The purpose of this study was to study marine litter on the Baiya beach, Palu Bay using a rapid beach survey from the pre and post tsunami time of Palu Bay on September 28 2018. The results of monitoring the amount of marine litter before the tsunami at Baiya Beach in 2017 contained 4 meso litter materials with 10 litter types. There were 6 materials of macro litter, found 24 litter types. After the Palu Bay Tsunami in 2018, monitoring in 2019 found 9 materials of meso and macro with 31 litter types. Monitoring in 2020 found 9 meso litter materials with 19 litter types. There were 9 materials of macro, found 29 litter types. The plastic increase in marine litter on Baiya beach during monitoring was dominated by PL24 (other plastics) and the tsunami incident increased the litter type of plastic.
Analysis of fatty acid profile on Rono Lindu (Oryzias sarasinorum) and Rono Poso (Adrianichthys oophorus) fishes endemic of Central Sulawesi
Authors: Widodo A , Ummiah R , Anam S , Pitriani  , Jamaluddin  
Published: February 2021

Abstract
Rono Lindu fish (Oryzias sarasinorum), and Rono Poso fish lake (Adrianichthys oophorus) are endemic fish of Central Sulawesi were consumed by the society, but it is have not known nutritional content. This research aims to determine the amount and the differences compositions of fatty acids in rono fish from Lindu and Poso lake. The research of fatty acid composition by using the Gas Chromatography method by changing the extraction of fats/oils into a form of FAME (Fatty Acid Methyl Ester). The results of the research showed that the number of fatty acid levels is different between the two samples. The composition of fatty acids found in Rono fish from Lindu lake is included saturated fatty acids (50.91665%), monounsaturated fatty acids (13.66273%), and polyunsaturated fatty acids (35.42044%). While the composition of fatty acids found in Rono fish from Poso lake is included saturated fatty acids (45.85161%), monounsaturated fatty acids (31.67566%), and polyunsaturated fatty acids (22.50430%).
Study of the effect of ionophore carbon chain length on the selectivity of the Nd (III) ion selective electrode
Authors: Husain S. , Buchari B , Indra N. 
Published: February 2021

AbstractIon selective electrode method is used for analyzing certain metal ions in a sample with ionophore as the link between two different solutions. The compounds 4-adipoybis (1-phenyl-3-methylpyrazolone-5) (H2AdBP) and 4-sebacoylbis (1-phenyl-3-methylpirazolone-5) (H2SbBP) are the same two types of ionophores but differ in the length of carbon chain. Both ionophores were used in potentiometric analysis of Nd3+ion and showed that H2AdBP-Nd electrode had a slightly smaller detection limit, namely 1.91 x 10−5M with a sensitivity of 15.9 ± 2.2 mV/decade with a response time of 23 seconds, compared to the H2SbBP-Nd electrode with a detection limit of 2.88 x 10−5M, sensitivity of 21.9 ± 1.1 mV/decade and response time of 22 seconds. The effect of pH on the electrode performance was studied by varying the pH, concentration of ISA KNO3and composition of the internal solution. Good electrode performance was obtained at pH 3 and the electrode sensitivity increased to pH 4. The electrode selectivity was carried out using a separate solution method (SPM) for the La3+, Ce3+and Th4+ions. The determination results ofKNd/jpotelectrode pot showed that ESI-Nd electrode was not selective against La3+and Ce3+ions but selective to Th4+with valuesKNd/jpot< 1.
The equivalence Vitali cover integral with Lebesgue integral
Authors: Pathuddin  , Bennu S , Hasanah S U 
Published: February 2021

Abstract
Collection interval v is called Vitali Cover measiu’able set up A ⊂ R, if for every number ε > 0 and x ∈ A is an open interval Ix
∈ v so that x ∈ Ix
and μ(Ix
) < ε. By utilizing Vitali Cover can be constructed of a type of integral type, hereinafter referred Riemaim Vitali Cover integral. A Function

f
:

[
a
,
b
]

→

R

¯

A function is said to Lebesgue integrable if and only if there is a continuous function

F
:

[
a
,
b
]

→

R

¯

so that F absolutely continuous on [a,b] and F′(x) = f(x) almost everywhere in [a,b]. By using the properties of Vitali Cover can be shown that both types of the above integral are equivalent
Production and characterization of cooking oil from crude palm oil
Authors: Jusman  , Syamsuddin  , Handayani Sri 
Published: February 2021

Abstract
Research has been carried out on the production and characterization of cooking oil with the Indonesian National Standard CPO (Crude Palm Oil). In principle, the raw material in the form of crude palm oil is adsorbed by natural bleaching which causes a color change in crude palm oil. This study aims to determine how much natural bleaching is used to reduce β-carotene from CPO (Crude Palm Oil) to comply with Indonesian National Standard for cooking oil, and how the characteristics of cooking oil adsorption using natural bleaching. The best mass of natural bleaching obtained according to Indonesian National Standard is 1.5 grams with β-carotene content of 30.664 ppm, water content of 0.59%, free fatty acid content of 0.53% and peroxide number of 0.8 mgO2/100 grams. The characteristics of the resulting cooking oil are clear yellow with a distinctive aroma.
A preliminary study of DSSC with PEDOT carrageenan as electrolyte system
Authors: Palamba A J , Sari N , Diah A W M , Saehana S 
Published: February 2021

Abstract
This study aims to produce DSSC solar cells using PEDOT as a substitute for iodine. This experiment was carried out in the physics laboratory of the Tadulako University FKIP. TiO2 was deposited on FTO glass measuring 2.5 x 2.8 cm using the doctor blade method. TiO2 film was produced after heating in a furnace at 450 ☐C. Subsequently, the film was soaked in Routinized dye for 30 minutes. PEDOT Carrageenan Lambda 1:1 is then dripped on a TiO2/dye layer and covered with a platinum counter electrode. The results of measurements of current and voltage under direct sunlight with an intensity of 746 W/m2 are 32.2 µA and 97.5 mV, respectively. These results indicate that the PEDOT Carrageenan solution has enough potential to be developed as a substitute for iodine electrolyte in the DSSC solar cell device.
Influence of formulation on physical stability of cherry (Muntingia calabura L.) leaves extract as an antibacterial
Authors: Sultan A , Parumpu F A 
Published: February 2021

Abstract
Cherry leaves have been known as an antibacterial and a natural antiseptic that contain flavonoids, saponins and tannins. This research aims to prepare two formulation of cherry leaves extract and to evaluate their physical stability as an antibacterial dosage form. cherry leaves were extracted using ethanol 96% by maceration method. The extract was formulated as a hydrogel with carbomer and a water-based cream with combination of stearic acid and TEA. Physical stability was determined at cool temperature (4°C) and room temperature (± 25°C) by organoleptic, pH, homogeneity, spread, and emulsion type test (for water-based cream). The results showed that all formula of hydrogel was stable in organoleptic, homogeneity and spread test, but the pH value was on 9 which is higher than normal skin pH. Otherwise, the water-based cream was stable in organoleptic, pH and spread test, but in formula 1 showed an emulsion phase separation and formula 3 showed a non-homogeneous arrangement and visible grain after 14 days of storage. Both of the preparation was suitable to applicate cherry leaves extract in antibacterial dosage form with data of skin irritation test.
Protease activity from bacterial isolates of Nepenthes maxima reinw. ex nees
Authors: Pratika M , Ananda M , Suwastika I N 
Published: February 2021

Abstract
Protease is an enzyme that applied in many industrial sectors. Protease can be produced by proteolytic bacteria. Many of these bacteria were isolated from Nepenthes that lives in nutrient-poor areas. The life of Nepenthes is depend on the insects that trapped and degradated by proteolytic bacteria inside the pocket of Nepenthes. Sulawesi has a high diversity of Nepenthes, there are many species of Nepenthes that endemic to Sulawesi. However, there is no report for isolation and characterization of proteolytic bacteria from Nepenthes, especially in Nepenthes maxima Reinw. Ex Nees. This study was aimed to characterize the protease from bacterial isolate of N. maxima Reinw. Ex Nees. The methods that used in this study were screening of samples from Nepenthes and protease activity assay at temperature 37°C with pH 7. The result showed that proteolytic index of BN1 was 0,64 mm, higher than other isolates. While the proteolytic index of BN2, BN3, BN4 and BN5 were 0.51 mm, 0.24 mm, 0.13 mm; and 0.54 mm, respectively. Isolate of BN2 were able to produce the highest protease activity (0,067 U/ml) and the lowest protease activity was produced by isolate of BN3 (0,008 U/ml). Protease activity of BN1, BN4 and BN5 were 0.015 U/ml, 0.023 U/ml and 0.055 U/ml, respectively. The result indicates that proteolytic baceria from N. maxima Reinw. Ex Nees has the potential to produce protease that can be used in large-scale industrial sectors.
The effect of sintering temperature on the mechanical properties of ceramic
Authors: Ismiati N , Darwis D 
Published: February 2021

Abstract
The purpose of this research is to utilize natural resources in the form of clay and white sand in ceramics formation and to determine the effect of sintering temperature on the mechanical properties of the ceramics (compressive strength, thermal shrinkage and porosity) made from clay and silica sand (SiO2) with a temperature variations. Ceramic formation used a mixture of clay and silica sand (SiO2) with a ratio of 70%: 30%, then mold and compacted them using a hydraulic press to a pressure of 5 Mpa. The samples were then heated in a furnace at temperatures of 700°C, 800°C and 900°C for 3 hours. The results of the calculation of mechanical properties show that all samples meet SNI standards and the ceramic that has the best quality is the ceramic sintered at a temperature of 900°C because it has the highest compressive strength, low thermal shrinkage and low porosity of 21.09 Mpa, 0.680% and 17.92 %, respectively.
The Relationship between The Postsecondary Education Readiness Test (PERT) Mathematics Score and Students’ Mathematics Problem-Solving Ability
Authors: Desyarti Safarini TLS , Wardhani Thalitha Ariesti Widhia 
Published: February 2021

Abstract
The study aimed to determine the relationship between PERT mathematics scores and students’ mathematics problem-solving ability. This study uses the correlation research design to determine the relationship between the two variables. The sample consisted of 29 freshmen students who have passed the PERT mathematics test and take college algebra class. The main instrument in this study is worksheet consists of two problem-solving questions. The PERT mathematics scores were used as the predictor variable of this research. Based on the SPSS analysis, the r score was 0.547, which describe that there exists a correlation between the PERT mathematics score and students’ mathematics problem-solving ability. The variation of PERT mathematics score can explain about 29.9% of the variation of students’ problem-solving ability. The rest 70.1% supposed to be explained by other factors. The results of these preliminary research studies can provide invaluable information on the direction of future research that may be required on the specific variables.
Analysis of Senior High School Student’s Difficulty in Resolving Trigonometry Conceptual Problems
Authors: Nanmumpuni Herlingga Putuwita , Retnawati Heri 
Published: February 2021

Abstract
Trigonometry is one of the topics in mathematics in senior high school that must be studied and has an important effect in the development of students’ creative thinking skills, but in reality there are some difficulties experienced by students. This research focuses on analysis difficulty in resolving trigonometry conceptual problems among senior high school students in every creative thinking skills level. This research used a descriptive method aimed to identify the difficulties and cause of the difficulties experienced by five students. The difficulties are associated with concept of trigonometry and related problems. Data collection was done based on students’ work through test, interview, and observations. The results revealed that students’ difficulties in understanding the concept of trigonometry can be found at almost every level of creative thinking skills. The difficulty is identifying the application of trigonometric concepts in daily life and seeing the interrelationships between the problems given.