bluuebunny/crossref_metadata_2025 huggingface dataset:
A UWB Location Algorithm---Based on Adaptive Kalman Filter
Authors: Yi Chen , Da An Ze , Hui Chen , Shan Chen , Xuan Zhou
Published: February 2021

In order to solve the problem of large fluctuations in UWB(Ultra Wide Band) positioning accuracy and solid-state deviations in the positioning results, which are in complex indoor environments, an adaptive Kalman filter method is introduced in the later stage of data processing. This method can better retain data information and obtain better filtering effects when the system noise is complex and measurement information is missing,.Thereby providing better positioning accuracy. The experiment uses AGV trolley equipped with UWB sensors to obtain measurement data, uses traditional Kalman filtering and adaptive Kalman filtering methods to compare the filtering effects of the algorithms. The experimental results show that when the measurement information is missing, compared with the traditional Kalman filter algorithm, the adaptive Kalman filter method is a real-time high-precision indoor positioning algorithm with higher positioning accuracy.
Research and Design of Electrical Stimulation Electrode Arrays Device
Authors: Tang Junquan , Wu Wenzhu
Published: February 2021

A wireless electrical stimulation device based on biological electrode array is developed. The stimulator uses the FPGA as the central controller, a 4 × 4 electrode array is built and direct digital synthesizer (DDS) is used to generate stimulating waveforms. To generate adequate current load on human body, an isolated bi-direction constant current source module is designed which can detect electrode loss, as well as provide safe bi-direction constant current. The host computer uses an interactive software for android system, and the stimulating amplitude, pulse width and frequency and the electrode selection can be adjusted flexibly. The ES electrode arrays device has the characteristics of small size, good stability, low power consumption, easy to operate. It will bring convenience to clinical applications and bioelectrical stimulation scientific researches.
Research on Blockchain-Based Organization Collaboration System
Authors: Zhang Zhibin , Xi Jianqing
Published: February 2021

Collaboration log, which can be used to reflect the trust of an organization and applied to subsequent analysis and audit, is constantly generated during the organization’s collaboration. Common systems usually store them by a third-party organization, which exists at risk of tampering. Regarding this issue, blockchain can safely manage the collaboration logs owing to its decentralized and unforgeable features. In this paper, we implement an organization collaboration prototype system for spare parts procurement based on the Software As A Service(SaaS) collaboration model and Hyperledger Fabric solutions. To validate the performance of the prototype system, we conduct some performance tests on the prototype system. The result shows the feasibility of our proposed system.
Deterministic iterative path planning algorithm based on node storage structure
Authors: Lu Hong , Di Yue , Yan Fan Jun
Published: February 2021

Aiming at the problems of low efficiency of path planning, a new node storage structure is introduced and the search method is optimized to improve the deterministic iterative path planning algorithm. First, the number of antibodies is determined based on the connectable starting path point, when generating the initial antibody with the inspiration of the optimal angle vaccine. Then, the connectable path point of the starting point is treated as the root node to rebuild the new path with path filtering by means of the optimal path fit value. The initial optimal antibody is used as the screening criterion to avoid invalid path point mutation with 100% confidence conditions. Finally, a path point is a basic unit that forms the connection network and stores the parameter information that reaches it. After the algorithm iteration, the optimal pathis output. In different maps, the algorithm in this paper is compared with others. The results show that the algorithm effectively reduces the computational cost and has better adaptability to different maps.
Causal Features Extraction for Workpiece
Authors: Liu Li , Huang Chen Xiang
Published: February 2021

In order to reduce the cost, computer vision technology is introduced into the measurement of workpiece size and shape on the factory production line. At present, the most widely used solution is the neural network model based on big data. However, the lack of data and the high cost of data processing also greatly limit the practical application of this aspect. The method of feature extraction brings challenges to the real-time, rotation invariance, and anti-noise of online detection. In this paper, firstly, Harris operator is used to extract feature points quickly. Then a two-layer scale space based on causality is constructed to filter the noise and project downward to obtain the robust feature position, which provides a basis for subsequent processing.
Research on Collaborative Filtering of Food Information Security in E-Commerce Platform
Authors: Luo Sheng
Published: February 2021

Recommender systems are one of the most important technologies in the electronic commerce system. In a collaborative filtering recommendation algorithm, similarity calculation is the key to determining the efficiency of the recommendation algorithm. This paper analyzes the shortcomings of traditional similarity measurement methods in recommender systems and proposes a scoring-matrix-filling algorithm. Based on information categories and user interest similarity, the algorithm can reduce the negative influence of data sparsity on the recommendation result to some extent. The research results have certain practical and guiding significance.
Investigation of the intermetallic coating of the Ni-Fe system obtained by surface laser treatment on a steel substrate.
Authors: Gerashchenkov D A , Kuznetsov P A , Makarov A M , Krasikov A V , Markov M A
Published: February 2021

The article presents the results of a study of the Ni-Fe system coating on a 09G2S (Fe-Mn9% Si2%) steel substrate obtained by laser surface treatment. The coating was obtained in two stages. At the first stage, a precursor coating (PC) of Nickel was applied by cold spray (CS). At the second stage, its surface was laser treatment. The article shows changes in the composition and properties of the coating after laser treatment at different thicknesses of the precursor coating and different laser treatment modes. The results of the study showed that the composition and structure of the coating can be controlled by controlling the thickness of the precursor coating, the scanning speed, the scanning hatch, and the number of repeated scans.
Effect of initial particle size and various composition on the spark plasma sintering of binderless tungsten carbide
Authors: Lantsev E A , Malekhonova N V , Chuvil`deev V N , Nokhrin A V , Boldin M S , Andreev P V , Smetanina K E
Published: February 2021

The results of studies of the kinetics of high-speed spark plasma sintering (SPS) of plasma-chemical nanosized and industrial micron tungsten carbide powders are described. During SPS the carburization of the surface layer of tungsten carbide samples takes place, which leads to differences in the phase composition and hardness of the surface and central regions of sintered ceramics. The process of SPS of tungsten carbide can be sequentially represented as a change of the following mechanisms: rearrangement of particles at lower temperatures (Stage I) → sintering of particles due to grain boundary diffusion (Stage II) → sintering due to diffusion in the crystal lattice (Stage III- 1) → sintering under conditions of intensive grain growth with an abnormally low diffusion activation energy (Stage III-2).
Superplasticity of fine-grained alumina obtained by spark plasma sintering
Authors: Popov A A , Chuvil’deev V N , Boldin M S , Nokhrin A V , Lantsev E A , Murashov A A
Published: February 2021

Investigations of plastic deformation of fine-grained ceramics based on alumina obtained by the method of spark plasma sintering in the temperature range of 1150-1320 ° C at an applied stress of 40-100 MPa are presented. Based on the experimental data, the parameters of rheological equations were established. It is shown that the mechanism of high-temperature deformation of alumina is superplasticity. In the process of plastic deformation, the grains of alumina do not stretch, which confirms the mechanism of superplasticity - grain boundary sliding. The activation energy for superplastic deformation was Q = 17.8 kTm at d = 6 μm and Q = 24.6 kTm at d = 1 μ m, which is very close to the activation energy of grain boundary diffusion in aluminum oxide Qb = 20 kTm. For a coarse-grained material, an assumption was made about a possible mechanism for lowering the activation energy due to the generation of dislocations by the grain boundary.
Electrochemical corrosion tests of Nd-Fe-B-based magnetic materials with modified structure
Authors: Skotnicova K , Kolchugina N B , Cegan T , Prokofev P A , Lasek S , Jurica J , Dormidontov N A , Bakulina A S , Rusinov D A
Published: February 2021

The wide application of Nd-Fe-B permanent magnets in addition to the rare-earth metal resource constrains determine the necessity of their recycling. One of approaches to magnet-to-magnet recycling consists in using the grain boundary modification of sintered magnet material, which includes the grain-boundary diffusion (GBD) and grain-boundary structuring (GBS). The preparation of magnets with the modified structure determines a need for research their corrosion resistance. The corrosion resistance of magnets prepared by powder blending techniques, namely, magnets, which were recycled from hard-disk drivers, in using Dy/NdH2 additions in the powder mixture and magnets, which were prepared from strip-casting alloy, in using TbH2 hydride in the powder mixture, is studied. The corrosion potential and polarization resistance were measured, and the average corrosion rate was estimated based on polarization measurements of the magnet samples in the aqueous solution 0.1 M NaCl. Furthermore, a pitting resistance corrosion test was conducted and the values of pitting and repassivation potential were determined. The corrosive properties of the magnet samples are discussed from the viewpoint of the phase compositions of the material.
Recent developments of microcapsules and polymer particles for separation medium
Authors: Shiomori K , Matsune H , Kiyoyama S , Takei T , Yoshida M , Umakoshi H
Published: February 2021

Microcapsules and porous polymer particles containing extractants, which are functional molecules to extract target ions or molecules by specific interaction using in solvent extraction process, are expected to be an effective separation medium of various substances from aqueous solution in hydrometallurgical process of harmful or valuable metals and in environmental protection processes from various pollutants. The preparation method, encapsulating materials and application area of these materials has been developed and extended in recent years. Recent topics of this field was been presented. The research on the polymeric particles for separation medium investigated by authors was introduced and showed the structural effect of the polymeric particles containing extractant on the separation performance of metal ion and chiral separation of amino acids by porous particles impregnated with phospholipids.
Mapping leachate distribution based on the self-potential method in Manggar Landfill, Balikpapan Indonesia
Authors: Arisalwadi M , Rahmania
Published: February 2021

TPA Manggar is a landfill in Balikpapan City. During the rainy season, the leachate discharge entering the processing plant is so large that the collection tub will not be able to withstand the leachate flow rate. To find out the direction of the distribution of leachate waste and the extent to which it has spread and to map the areas at high risk of being contaminated, measurements were taken using the Geophysical method, namely the Self Potential Method (SP). The SP method is based on measuring the self-potential of rocks in the earth’s crust without having to inject an electric current into the soil. Based on this, research will be carried out to determine the mapping of the distribution of leachate flow in the TPA Mangaar area. The results of measurement and processing of self-potential data can be showing beneath the surface in the form of leachate distribution in the study area based on isopotential contour. Based on the results of contour and isopotential map data processing. The highest potential value of this study was 60 mV, while the lowest potential value of this study was -40 mV.
One-dimensional data analysis for aquifer layer in Pancuma Village, Tojo Una-Una, Central Sulawesi
Authors: Sastrawan F D , Wulandari R , Rusli M , Rahmania  , Arisalwadi M
Published: February 2021

The need for water resources continues to increase from year to year to meet various needs. The availability of water resources is increasingly limited due to seawater intrusion or water pollution. Pancuma Village is one of the coastal areas where it is necessary to study the potential of groundwater, especially during the dry season. One way to determine the presence of the groundwater aquifer layer is by using the resistivity method. This method is an effective geophysical method for shallow exploration so that it can be used to determine the structure beneath the earth’s surface. The configuration used in this study is the Schlumberger configuration. Research in Pancuma Village aims to determine the subsurface stratigraphy of the study area based on the resistivity value and to determine the distribution of groundwater aquifers in the study area. The results obtained from this study are that there are four types of subsurface layers in the study area, namely topsoil, claystone, iron sand, and alternating sandstone with conglomerates which are the aquifer layer in the study area. The resistivity value estimated at the aquifer layer ranges from 119 Ωm - 529 Ωm with a thickness of up to 45 meters.
Rock porosity estimation research using refraction seismic waves in Bora Village, Sigi Regency
Authors: Sandra  , Efendi Rustan , Astuti Meila , Rusydi  , Badaruddin  , Iqbal
Published: February 2021

Rock Porosity Estimation Research Using Refraction Seismic Waves in Bora Village, Sigi Regency has been conducted. The purpose of this study was to determine the distribution of porosity of shallow subsurface rocks at geothermal locations. Data is collected on 6 different trajectories using ES-3000 to get a picture of subsurface waves. The data processing method uses Seisimager software to get a cross-section of the wave velocity and Rockwork software to get a cross-section of the porosity of subsurface rocks. The results showed different rock porosity values for each trajectory. Rock porosity values obtained at track 1 to track 6 are in the range of 27.1% to 30.5%. All trajectories are on a special porosity scale which means they have a large porosity volume as a place to store fluid.
Analysis of factors affecting the level of poverty in Central Sulawesi
Authors: Handayani L , Rais  , Putera F H A
Published: February 2021

Poverty is a problem faced both nationally and globally. Central Sulawesi Province is one of the provinces in Indonesia with an economic growth rate that is above the national rate, which is inversely proportional to the amount of poverty that occurs. This study aims to find a model using ordinal logistic regression analysis to predict predictor variables that affect poverty and rank the influencing predictor variables using dominant analysis. Based on 11 predictor variables that are thought to be closely related to the characteristics of poverty with the approach of poor households in Central Sulawesi province, ordinal logistic regression analysis concludes that seven predictor variables that affect it are X1 (floor area), X4 (roof), X5 (latrine facilities), X6 (drinking water), X9 (credit), X10 (assets), and X11 (aid rice). The importance of the seven predictor variables can be ranked using dominant analysis. The dominant analysis concludes that the highest importance in influencing poverty in Central Sulawesi province is the variable X11 (aid rice) followed by variables X6 (drinking water), x5 (latrine facilities), X1 (floor area), X4 (roof), X10 (assets), and X9 (credit).
An application of super mean and magic graphs labeling on cryptography system
Authors: Sudarsana I W , Suryanto S A , Lusianti D , Putri N P A P S
Published: February 2021

An edge-magic total (EMT) labeling on a simple graph G with p vertices and q edges is a bijection f: V∪E→{1, 2, …, p + q} such that for each edge xy of G, f(x) + f(xy) + f(y) = k, for a fixed positive integer k. Moreover, an EMT labeling f is a super edge-magic total labeling (SEMT) if f(V) = {1, 2, …, p}. Furthermore, a graph G is called a super mean (SM) graph if there exists an injective function f from the vertices of G to {0,1,2,…,q} such that when each edge uv is labeled with (f(u) +f(v))/2 when f(u) +f(v) is even, and (f(u) +f(v) + 1)/2 when f(u) +f(v) is odd, then the resulting edge labels are distinct. There are two essentials results that will be proposed in this paper. In the first result, we show that a graph (n, 1) − F Caterpillar has a SM labeling and a graph Hu,y

K

¯

n

has a SEMT labeling. In the second result, we will give an application of these labeling to increase the security level of Affine Cipher in which to encrypt a text on socials media.
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

Chicken 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

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

The 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

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

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

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

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

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

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

Ion 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

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

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

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

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

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

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

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

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.
An Investigation of Indonesian In-Service Mathematics Teachers’ Perception and Attitude Toward STEAM Education
Authors: Ishartono Naufal , Sutama  , Prayitno Harun Joko , Irfan Muhammad , Waluyo Mohamad , Sufahani Suliadi Firdaus Bin
Published: February 2021

To face the global challenge, people need to master mathematics comprehensively which one of the ways is to integrate it with other fields such as science, technology, engineering and arts. Therefore, the implementation of STEAM Education approach is considered to be essential for in-service mathematics teachers especially in Indonesia. This study aimed to investigate the perceptions and attitudes of Indonesian in-service mathematics teachers towards the application of STEAM-based education in the teaching mathematics. Cross-sectional survey was used in this study engaging 110 respondents along the survey. The result was that STEAM Education is nor well-known by the majority of the respondents. For the perception, those who knew STEAM Education mostly believed that each topic of this approach was connected to each other, otherwise for those who did not know STEAM Education mostly said that each topic was stand alone. As for the attitude of respondents also divided into two, the first group of respondents stated that STEAM Education will be increasingly popular in the future and they will feel happy if teaching mathematics with STEAM Education. Whereas the second group of respondents looked more pessimistically related to projections of future application of STEAM Education that would be less popular, not to mention that they would feel unexcited to teach mathematics with the STEAM Education approach.
Development of the assessment model based on order thinking skills (HOTS) to measure students’ critical thinking
Authors: Seyaningsih Nining , Sari Widya Ayu Kurnia
Published: February 2021

This study aims to develop the assessment model based on HOTS to measure students’ critical thinking. This research uses the Research and Development (R&D) method. The instruments used in this study were assessment instruments and validation sheets of media and material experts. The characteristics of this study are the assessment instruments that measure the ability of students to solve problems that require high-level thinking skills and critical thinking. The subjects of this research are grade 8 students of SMP Muhammadiyah 4 Surakarta. The results showed that the assessment model developed was included in the good category used for the learning process. This is shown, the results of the validation of the material experts obtained percentage of the aspects of feasibility content is 0,92, percentage of the aspects of feasibility of construction is 0,82 and percentage of te aspects of language worthiness is 0.82. The results of the validation of the media experts showed a mean score of 3.6. The characteristics of instruments regarding distinguishing features and difficulty levels indicate the percentage of 0.39 and 0.49. Based on the results of student work using the HOTS-based assessment model in SMP Muhammadiyah 4 Surakarta shows that the ability critical thinking is still in the good enough category.
Junior high school students’ mathematical connection: a comparative study of children who have reflective and impulsive cognitive styles
Authors: Warli  , Nofitasari Y
Published: February 2021

Mathematical connections are the link between mathematical topics and mathematics, with other disciplines and to the real world or in daily life. The purpose of this study was to describe the mathematical connection ability of junior high school children who have impulsive and reflective cognitive styles. To achieve that objective, comparative research is done both qualitatively and quantitatively between reflective and impulsive students. The research subjects were students of SMP Negeri 1 Palang who had impulsive and reflective cognitive styles. To measure impulsive and reflective cognitive styles the MFFT (Matching Familiar Figures Test) instrument is used. The mathematical connection instrument is a mathematical connection test while exploring the mathematical connection skills used by task-based interviews. Based on the results of the qualitative analysis, it was concluded that reflective students can recognize and use the relationship between ideas in mathematics better than impulsive students. Reflective students are also able to show quite well how mathematical ideas are interconnected and build on each other to produce a coherent whole, but impulsive students are less able. On indicators of recognizing and applying mathematics in contexts outside mathematics, both reflective and impulsive children have the same difficulty. The results of the statistical analysis of the mathematical connection score, there were no significant differences between reflective and impulsive students.
Varying coefficient model of longitudinal data of dengue fever in Bandung city
Authors: Tantular Bertho , Andriyana Yudhie , Ruchjana Budi Nurani
Published: February 2021

Studies on infectious diseases, especially those transmitted through intermediaries such as dengue fever, are sometimes seen as growth patterns over time. The measurement is repeated over time and hence we have a longitudinal data structure. We are interested in analyzing factors that influencing the dengue fever rate. A Modelling technique is used to determine the effects of covariates, but there are variable where the effects of covariates may also change over time when the effects of covariates change over time. Varying coefficient model is an alternative to model such situation to determine these effects. In general, the model will form a pattern, both linear and non-linear. As the objective function, we propose to use a P-Splines Quantile Objective function such that a flexible dengue pattern can be developed. The proposed technique will be implemented to dengue fever cases in Bandung City. The density of Bandung City is a factor that causes the spread of infectious diseases. In addition, various risk factors for the spread of dengue cases in Bandung are also taken into account, such as rainfall, temperature or temperature and humidity. Another factor that can be a covariate is the lifestyle factor of the people of Bandung, such as clean and healthy living behaviour and healthy house. The result shows existence of a nonlinear pattern, and the fluctuations in the incident value that changes over time. There are changes in the values of the intercept and slope coefficients over time for each level of the quantile.
Analysis of Orthogonal Matching Pursuit Using Orthogonal Bases on Digital Image
Authors: Imaduddin Muhammad , Farikhin  , Hariyanto Susilo
Published: February 2021

In this paper, we develop an image processing technique that is developed to build any image into the original image, with high image quality and small storage space. The image to be used is in the form of an RGB image which is then processed into a binary image to be represented in the form of a matrix. In addition, we also corrected Compression Sensing to reduce the image sampling rate and improve the accuracy of image reconstruction. In this study, the Orthogonal Matching Pursuit algorithm was used for the image reconstruction process. While the bases used in the image reconstruction process using the Orthogonal Matching Pursuit (OMP) Algorithm are the bases of Haar, Hadamard, and Walsh. The results of the research after reconstruction are that the results of high quality images are obtained, but have less storage space, have good MSE and PSNR values and require a short time during reconstruction.