bluuebunny/crossref_metadata_2025_split huggingface dataset:
The characterization of hydroxyapatite from blood clam shells and eggs shells: Shyntesis by hydrothermal method
Authors: Kusuma H H , Sifah L , Anggita S S 
Published: June 2021

Abstract
Hydroxyapatite is a bioceramic that can be used as a denture material. Hydroxyapatite can be produced by synthesizing blood clam shells and eggshells as a source of calcium and (NH4) 2HPO4, phosphate through hydrothermal methods. The hydroxyapatite samples were characterized by XRD and FTIR. The results of XRD analysis showed that the hydroxyapatite produced contained calcium carbonate (CaCO3) and apatite carbonate type A. Hydroxyapatite has a hexagonal structure with lattice parameters a = 9.404 Å and c = 6.675 Å the resulting crystal size ranges from 10.19 nm to 57.29 nm. The results of the FTIR spectrum of the hydroxyapatite sample contained functional groups PO4
3-, OH− and CO3
2- which are functional groups of hydroxyapatite.
Application of microseismic methods for identification of ground movement potential in Cemara sub-village, Sukorejo village, Gunungpati Semarang
Authors: Khumaedi  , Supriyadi  , Sugiyanto  , Pratiwi N A 
Published: June 2021

Abstract
Based on data of landslide from Regional Disaster Mitigation Board (BPBD), Sukorejo village is one of three urban villages in Gunungpati which has a high potential possibility for disaster, particularly landslide. One of the areas in Sukorejo Village that frequently sustains of land movement is Kampung Cemara. On April 23, 2018 in Kampung Cemara, a landslide occurred which caused detrimental damage to buildings. Several other accidents signified ground movement resulting cracks in the land surface. The high level of losses is not only induced by the magnitude of the disaster, but also due to inadequate information related to the potential for disasters and conditions in the area, that it decreases public awareness of the environment. That is the main reason for this micro seismic research. Micro seismic is a geophysical method which employ to determine the ground motion potency through the subsurface layer characteristics by calculating the value of Ground Shear Strain (GSS). The data processing is using the HVSR method. The value was ranged from 4.54 × 10−3 to 1.59 × 10−2. The result represents that Kampung Cemara is considerably potential to undergo land movements with plastic-elastic soil properties and ground motion phenomena that can effect vibration and cracks in surface land and habitation.
Discrepancy evaluation models in physics project based learning of student entrepreneurship character
Authors: Jumini S , Rusilowati A , Sutikno S , Cahyono E , Parmin P , Firdaus F 
Published: June 2021

Abstract
Discrepancy Evaluation Models(DEM) of Information Technology-based Project Assignment Programs in learning Physics are conducted to see whether there are gaps so that the effectiveness of the program can be continued or not. The evaluation technique is carried out by conducting interviews with supporting lecturers, observing lecture processes, and questionnaires to supporting lecturers and students. The results showed that (1) Information technology-based Project assignment program in learning Physics was carried out well with a score of 3.70. (2) The program can be done by giving students assignments by making applied physics products that can be utilized in everyday life, then presented to see the truth of the physical concept and the clarity of the product made, then students upload the video to YouTube to see the market response. (3) Information technology-based project assignment programs in physics learning provide a clear picture of how physics works in the community. The integration of Economics of Science, entrepreneurship, Nature of Science can better provide a clear picture of how Physics works in society. Thus this program can be continued by revising several existing stages.
An analysis of thinking patterns of natural sciences teacher candidate students in understanding physics phenomena using P-Prims perspective
Authors: Juliyanto E , Siswanto S 
Published: June 2021

Abstract
This research aimed to identify thinking patterns of natural sciences teacher candidate students in understanding physics phenomena. Results of thinking patterns could be used to determine approriate learning models and materials for students’ thinking capacity. In this research, thinking patterns were analyzed using Phenomenological Primitive (P-Prims) perspective. A random sampling technique with purposive sampling was used. The sample consisted of undergraduate students majoring in natural sciences education of Tidar University. The research method used in this research was qualitative, accompanied with The Investigation of Lived Experience with Cognitive Psychology type. Data were collected using tests and interviews. The research results show that in explaining unfamiliar physics phenomena which had never been taught before, students used 1) inductive thinking pattern, by calling back their existing, relevant knowledge and 2) deductive thinking pattern, by using synthesized general premises.
Conversion of palm oil fuel ash (POFA) into foamy geopolymer for lightweight building material application by aluminum powder addition
Authors: Kusumastuti E , Desita R , Prasetya A T , Sulistyaningsih T , Sulistyani M 
Published: June 2021

Abstract
Palm Oil Fuel Ash (POFA) is produced from the burning of palm oil solid waste biomass. POFA is abundant in Indonesia considering that Indonesia is one of the world’s largest producers of Crude Palm Oil (CPO) and has the largest palm oil plantation. The main content of POFA is SiO2 around 60%, Al2O3 around 3-10% and CaO around 5-15% so that POFA has the potential to be developed as aluminosilicate inorganic polymers. The high SiO2/Al2O3 ratio in POFA needs to be reduced for the formation of Si-O-Al chains in geopolymers. Therefore, two stages of research were carried out. Preliminary research was conducted to obtain optimum Solid/Liquid ratio. Aluminum powder was then added with certain variations to get a certain SiO2/Al2O3 ratio as well as a foaming agent so that the product can later be used as a porous building material. The preliminary results showed that the optimum Solid/Liquid ratio obtained was 0.83. The addition of aluminum powder was optimum at 2% w/w with a compressive strength of 5.4233 MPa, a density of 1339.2175 kg/m3, and a thermal conductivity of 0.6233 Watt/m°K. This geopolymer product can be categorized as a lightweight building material with criteria: a compressive strength of 0.5-10 MPa, densities between 600-1800 Kg/m3, and a thermal conductivity of 0.1-0.7 Watt/m°K which can be used as panels in buildings, casting walls, and ornaments in parks.
Optimization and evaluation of ionically cross-linked alginate-hpmc nanospheres for encapsulation of bromelain as antiplatelet
Authors: Gayatri A , Hudiyono S , Setiasih S 
Published: June 2021

Abstract
Thrombus is blood congealment process (platelet) occurred in area of vein and is useful for preventing of bleeding occurrence. The considerable amount of thrombus in blood leads to blocked arteries and angina pectoris. The partial purification of bromelain originated from pineapple core (Ananas comosus [L.] Merr) with the specific activity of 124.38 U/mg had inhibition activity to the platelet aggregation of 86.48%. On the other hand, the proteolytic activity of bromelain was relatively stable in the first 4 hours. However, the proteolytic activity significantly decreased in the next 4 hours due to the influence of gastric fluid (pH 1.2). To overcome the problem, bromelain must be encapsulated into alginate-hpmc nanospheres cross-linked by cation (CaCl2). Based on the optimization result of the swelling index and the entrapment efficiency, the nanospheres with the composition of alginate-hpmc 1: 1 and 1:2 were the optimal formula and selected to encapsulate bromelain and be characterized by PSA and SEM. Alginate-hpmc nanospheres (1:1) had a particle size of 543.7±4.2 nm. The morphology of nanospheres were almost spherical and had a smooth surface. Moreover, the particle size of alginate-hpmc nanospheres (1:2) was 515.3±26.7 nm and the SEM micrographs showed the spherical nanospheres with slightly rough surface. The swelling degree, entrapment efficiency, PSA, and SEM data will relate to suitability of the nanospheres formulation to orally deliver bromelain.
Preparation of magnetite coated humic acid (Fe3O4-HA) as malachite green dye adsorbent
Authors: Sulistyaningsih T , Ariyani S , Astuti W 
Published: June 2021

Abstract
Magnetite (Fe3O4) coating using humic acid (HA) to form Fe3O4/HA as malachite green dye adsorbent has been carried out. Humic acid was obtained from the isolation of peat soil from Rawa Pening, Ambarawa, Central Java, using the conventional alkaline extraction method. Synthesis of magnetite and Fe3O4/HA by coprecipitation method under alkaline conditions using NaOH. The characterization using Fourier Transform Infrared (FTIR) shows a bond between carboxylate groups in HA and Fe on magnetite, which proves that HA coating on magnetite surfaces has been successfully carried out. The characterization results using X-Ray Diffraction (XRD) showed that the coating of HA on magnetite did not change its phase shape but decreased its peak intensity. The results of characterization using a Surface Area Analyzer (SAA) showed that HA coating increased the surface area of Fe3O4. The optimum adsorption of malachite green by HA occurred at pH 3 for 60 minutes, with a concentration of 96.95 mg/L. Magnetite adsorbs optimally at pH 7 for 90 minutes and a concentration of 83.48 mg/L, while Fe3O4/HA occurs at pH 3 for 90 minutes with 104.15 mg/L.
Synthesis of polysulfone and nitrated polyeugenol based flat imprinted membrane for selective adsorption of gold
Authors: Djunaidi M C , Kusumaningtyas S A , Widodo D S , Harris A , Pardoyo  
Published: June 2021

AbstractGold (Au) is the most valuable metal compared to the other metals contained in electronic waste and adsorption is a promising method for its recovery. In this research, a flat ionic imprinted membrane (IIM) was synthesized utilizing polysulfone and nitrated polyeugenol (NPE) for the adsorption of Au. Nitrated polyeugenol was synthesized by dissolving polyeugenol in chloroform and adding it into a mixture of HNO3and H2SO4. The evidence of a successful nitration process was marked by the appearance of NO2spectra in the wavenumber area of 1533 cm−1and 1302 cm−1. The resulted NPE was then contacted with Au and analyzed by XRD. IIM synthesis was done by using polysulfone as its base, NPE-Au as its functional polymer, and polyethylene glycol (PEG) as its crosslinker. Au was then released from the membrane by immersing the membrane in thiourea solution. The membrane was characterized by SEM-EDX to examine the surface morphology. It was then used as a selective adsorbent towards Au and the adsorption results were analyzed by AAS. The results showed that the IIM is more selective towards Au compared to the non-imprinted membrane (NIM) in a selectivity test towards Cd and Cu but not in Fe.
Synergistic effect of trichloroethylene and Cu(II) on DNA-adduct 8-hydroxy deoxyguanosine (8-OHdG) formation as a biomarker of cancer risk
Authors: Nurhidayat I , Budiawan  
Published: June 2021

Abstract
Identification of the synergistic effect of trichloro ethylene and Cu (II) in the formation of DNA adduct 8-hydroxy deoxyguanosine (8-OHdG) as a cancer biomarker were carried out. TCE and CuCl2 were incubated with deoxyguanosine with variations in temperature (37°C and 60°C) and pH (7.4 and 8.4) for 6 hours. The 8-OHdG levels formed were analyzed using high performance liquid chromatography (HPLC). The formation of 8-OHdG from exposure to TCE seems to require high concentrations, because of its difficulty to oxidize. The addition of Cu (II) was shown to have a synergistic effect with TCE in the formation of DNA adducts which increased up to 65.8%. Temperature did not have a significant effect on DNA adduct formation. Furthermore, it is found that alkaline pH produces more DNA adducts than neutral pH.
Electrospinning of nanofibers chitosan/PVA-sodium silicate
Authors: Mahatmanti F W , Kusumastuti E , Wijayati N 
Published: June 2021

Abstract
Chitosan is one of the biomaterials used in making membranes using electrospinning techniques. Chitosan was chosen because it has high biocompatibility and biodegradability. Chitosan solution has high viscosity even at low concentrations therefore this polymer is very difficult to be electrospinned without other polymers addition. Mixing polymer solution is a method commonly used to provide the desired polymer solution material with combined properties for certain applications. Polyvinyl alcohol is an excellent material for making fiber. In making membranes using solvent evaporation techniques, sodium silicate added to the chitosan solution will make the chitosan-silica membrane become porous even though the effect is not significant. This article will discuss the effect of adding sodium silicate to the manufacture of chitosan-PVA-sodium silicate membranes using electrospinning method. The results showed that sodium silicate solution addition to CS/PVA polymer solutions increases the fiber diammeter percentage to be <100 nm and increased the fiber uniformity, especially in chitosan/PVA polymer mixtures with volume ratio of 2:8. The addition of sodium silicate solution to the chitosan/PVA polymer solution reduces the CS/PVA-sodium silicate fibers thermal stability but increases the CS/PVA-sodium silicate fibers hydrophilicity.
Characterization compound chemical from cocoa waste as acetic acid and phenol
Authors: Wijaya M , Wiharto M , Auliah Army 
Published: June 2021

AbstractPotential Cocoa bean and derivative products consist compound of polyphenols and different potential levels of antioxidants. The greater content of polyphenols provides benefits to human health, cosmetic and food functional. Pyrolysis compounds under go decomposition into lignin, hemicellulose, and cellulose in the biomass waste that produce liquid smoke, tar, charcoal and other. The results of produce liquid smoke, tar and charcoal. Analysis of the lignin content of the cocoa pod husks from Barru District was 44.98%, cellulose was 60.03%, hemicellulose 15.54%, while the lignin content analysis of cocoa pod husks from Sidrap was 43.17%, cellulose was 43.26%, hemicellulose is 3.13%, and other is 31.3%. At a pyrolysis temperature of 514 ° C, the acetic acid content was 8.94% and the phenol content was 1.23% for the liquid smoke of the fruit skins of Barru Regency, while the acetic acid content was 4.37% and the phenol content was 9.34% for liquid smoke Sidrap Regency, From the separation of chemical compounds from the liquid smoke of cocoa pod skin in Barru Regency, it turns out that the highest content of acetic acid is 42.61% and phenol by 5.56% compared to other chemical compounds. From the separation of chemical compounds from the liquid smoke of the cocoa pods in Sidrap Regency, it turned out that the highest content of acetic acid was 42.51% and phenol by 5.54% compared to other chemical compounds.
Polymerisation behaviour of water hyacinth-based bio-oil during heating up in the presence of oxygen-containing compounds
Authors: Kadarwati S , Farida R , Kasmui  , Harjono  , Fardhyanti D S , Dewajani H 
Published: June 2021

Abstract
Bio-oil is susceptible to repolymerisation due to its high content of reactive oxygen-containing compounds. In this work, the polymerisation of the bio-oil produced from fast pyrolysis of water hyacinth was investigated during heating-up at various temperatures (50-95°C) in the presence of extra oxygen-containing model compounds (methanol and sucrose) with various concentration (10-50 wt%). The coke formed during the heating was quantified. The stability and reactivity of the hyacinth-based bio-oil for 48-h storage in the presence and the absence of the oxygen-containing compounds was also evaluated. This study showed that the presence of methanol in the bio-oil during heating up could suppress the repolymerisation leading to coke formation even at a higher temperature. In contrast, coke formation was severe (18.94 wt%) during the bio-oil heating up in the presence of sucrose at higher temperature (95°C). The presence of sucrose in the bio-oil could possibly promote the repolymerisation leading to coke formation. The repolymerisation possibly continued to occur during storage indicated by the increase in the viscosity, density and coke propensity of the bio-oil with added 50 wt% of sucrose compared to a negligible change in those properties of that with added methanol.
Dye-sensitized solar cells with napthol blue black as dye sensitizer
Authors: Setyawati H , Darmokoesoemo H , Murwani I K 
Published: June 2021

Abstract
Nowadays, fossil fuel supply is decreasing over time. Thus, people are required to look for alternative energy sources that are renewable and environmentally friendly. Dye-Sensitized Solar Cells (DSSC) is one of the promising sources to overcome those problems. In this research, a DSSC with naphthol blue-black (NBB) as dye sensitizer has been developed. In order to improve the performance of the DSSC, NBB was modified by inserting Fe to form Fe-NBB complex compound. Fe-NBB showed light harvesting characteristic through MLCT phenomenon (Metal to Ligand Charge Transfer) at 273 nm and metal-ligand bonding at 486.06 cm−1 and 316.33 cm−1. NBB and its derivatives (Fe-NBB) were applied as dye sensitizer in the DSSC. The obtained open circuit voltage, short circuit current, and efficiency for NBB were 0.218 V, 0.096 mA/cm2 and 0.0083 %, respectively. While, Fe-NBB were 0.363 V, 0.567 mA/cm2 and 0.0925%.
In-vitro Interpretation of 8-OHdG Formation as Cancer Risk Biomarker due to Malondialdehyde (MDA) and Cr (VI) Exposure through Fenton–Like Reaction
Authors: Afdila N , Budiawan  
Published: June 2021

AbstractMalondialdehyde (MDA) has been widely reported as a biomarker. Endogenous genotoxic products formed from the results of lipid peroxidation and oxidative stress can bind and modify proteins, phospholipids, and DNA to form stable adducts. The increase of oxidative stress triggers how the adducts are formed—formation of adducts linked to various patterns of diseases such as cancer, cardiovascular, and neurodegenerative diseases. The research objective was to interpret 8-OHdG formation, which is triggered by oxidative damage of genetic code (2’-deoxyguanosine) exposure to chemical compounds MDA and chromium (VI). This research was done by using in-vitro studies using MDA compound and Fenton-Like reactions. The variation of reaction conditions were at 7.4 and 8.4 pH condition, 3 and 16 hours of the incubated period at the temperature of 37°C and 60°C. The reaction products were analyzed by HPLC. From this analysis, 8OHdG target compounds were found. The correlation coefficient’s value is 0.9973. The value of LOD is 11.03 μg/L, and the LOQ value is 36.77 μg/L. In vitro test to MDA compounds at 60°C incubation temperature conditions for 3 hours, and pH 7.4 produced the highest concentration of 8-OHdG, 404,09 μg/L.
Factors affecting the utilization of cow dirt as a biogas energy source in Gogik Village, West Ungaran sub-district
Authors: Heriyanti A P , Budiyono  , Purnaweni H , Dewi N K , Khusniati M 
Published: June 2021

Abstract
The purpose of this study is to analyze the factors that influence the use of dairy cow dung as a source of biogas energy in Gogik Village, West Ungaran District. In this study, the method used is a qualitative method by conducting in-depth interviews, observation, and documentation. The results of this study indicate that the factors that influence the use of biogas energy sources can be viewed from technical factors, social factors, and economic factors. In terms of the availability of livestock and manure produced by Gogik Village, it is feasible to implement biogas technology on a household scale. In terms of livestock raising, Gogik Village has indeed met the eligibility requirements for the implementation of biogas. The community using biogas in Gogik Village has provided a land area according to the provisions of about 20 m2. In terms of social factors, the application of biogas technology in the community must be adjusted to the habits or culture of the community groups. On the other hand, the labor required to manage biogas in Gogik Village ranges from one to two people. In terms of economic factors, the effect of biogas use on community needs has not been fully felt by the biogas user community.
Experimental and kinetic study of free fatty acid esterification derived from Ceiba pentandra seed oil with ethanol
Authors: Kusumaningtyas R D , Haifah  , Widjanarko D , Prasetiawan H , Budiono Y W P , Kusuma A D H , Anggraeni N D , Kurnita S C F 
Published: June 2021

Abstract
Indonesia has an abundant feedstock of Ceiba Pentandra which is very potential as a source for biodiesel production. However, it contains very high free fatty acid and can not be directly converted into biodiesel through transesterification process. One of the solution is by reacting Ceiba pentandra oil with ethanol under acid catalyst called esterification process. In this study, the operating conditions used for esterification reaction was Ceiba pentandra oil to methanol molar ratio of 1:12; with reaction time of 120 minutes. The reaction temperature was varied into 40°C, 50°C, 60°C and 70°C. The results show that, highest conversion achieved was 93.5% at reaction temperature of 70°C. Based on the experimental data, pseudo-Homogeneous model was used to model the kinetic of esterification reaction. Based on this model, the activation energy was 21.319kJ/mol and the kinetic factor was 14,264.08/minutes with R2 of 0.9675 and SSE of 0.0004.
Recovery of high purity sodium chloride from seawater bittern by precipitation-evaporation method
Authors: Jumaeri  , Mahatmanti F W , Rahayu E F , Qoyyima D , Ningrum A N K 
Published: June 2021

Abstract
Seawater bittern is a liquid that still exists after most of the NaCl has crystalized in the production of salt from seawater. The main components of the liquid are MgCl2 and NaCl. This study aims to recover the NaCl present in bittern through the precipitation method with NaOH and evaporation. The initial stage of this research was collection of bittern in the salt production process in a salt pond. The obtained bittern samples were then added with NaOH to precipitate the MgCl2 components as Mg(OH)2 and leave NaCl as filtrate. The precipitate and the filtrate were separated by filtration. The obtained NaCl filtrate is then evaporated to obtain high purity NaCl. The product obtained was then determined the NaCl contents by argentometric titration. NaCl crystal was characterized using FTIR spectroscopy XRD spectroscopy, and Scanning Electron Microscope (SEM). The recovery results showed that the NaCl obtained had a high purity of 98.75% w/w and yield 30,45%. The IR spectra and diffractogram obtained showed compatibility with the characteristics of the reference NaCl.