bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Nanocomposite Silver-Chitosan-Alginate Film as Antibacterial Material
Authors: Susilowati E. , Maryani  , Ashadi  , Masykuri M. , Hastuti B. 
Published: August 2020

Abstract
Preparation of silver-chitosan-alginate (Ag/Kit/Alg) nanocomposite film as an antibacterial material has been done. Nanocomposite film of Ag/Chit/Alg was carried out through casting method of colloidal nanocomposite Ag/Chit/Alg). Colloidal is made through a chemical reduction method of AgNO3 precursor salts assisted by sunlight with chitosan as a stabilizer agent and reducing as well and NaOH as an accelerator. Furthermore, alginate solution is added to form Ag/Kit/Alg nanocomposite colloidal. The formation of silver nanoparticles was indicated by the appearance of localize surface plasmon resonsnce (LSPR) phenomenon which was characterized using a UV-Vis spectrophotometer. The shape and size of silver nanoparticles were characterized using TEM. Characterization of Ag/Kit/Alg nanocompsite films includes swelling, mechanical properties, solubility and water vapor permebility (WVP). Testing of antibacterial activity was carried out on film Ag/Chit/Alg nanocomposit using diffusion method. The results showed that the formation of silver nanoparticles was characterized by the appearance of LSPR phenomenon at the peak of 403.50 - 412.50 nm. Silver nanoparticles are spherical shape with a size dominated at 5-9 nm. The physical and mechanical properties of films are influenced by the concentration of silver nanoparticles. The greater concentration of precursor salt AgNO3 increase swelling and solubility of Ag/Chit/Alg nanocomposte film. The tensile strength of the film tends to decrease due to the presence of Ag nanoparticles. The nanocomposite film of Ag/Chit/Alg has a rough structure with a higher Water Vapor Permeability value compared to Ag/Chit films. The nanocomposit films of Ag/Kit/Alg have high antibacterial activity against Escherechia coli (E. coli) ATCC 25922 and Staphylococcus aureus (S. Aureus) ATCC 25923.
Tio2 Purification From Ilmenite The Tin Industry By-Product For Pigment
Authors: Aviandharie S A , Aidha N N , Jati B N , Ermawati R , Cahyaningtyas A A 
Published: August 2020

Abstract
Ilmenite deposits, a by-product of the tin industry in Bangka, cause environmental problems. Ilmenite is very abundant and has great potential because it still contains 53.83% titanium oxide. One of TiO2 benefits is for pigment. TiO2 pigment in Indonesia still imported. TiO2 pigment can be applied to various industrial sectors such as paints, coatings, fillers, semiconductor materials. This research aims to extract TiO2 from ilmenite with purity level above 80%. The TiO2 extraction used repeated leaching methods with sulfuric acid. Then followed by the hydrolysis process with the addition of seed and calcined. TiO2 products were analyzed using X-ray fluorescence (XRF) and X-ray diffraction (XRD). The content of TiO2 obtained in this process is 83.36% and is in the form of rutile crystals. The purity and crystal formed of this TiO2 product suitable with the minimum standards of TiO2 pigments required by ASTM D 476 (2015). This research can be the alternative to solve environmental problems in the tin industry while increasing the economic value as TiO2 products that has great market potential in Indonesia since there is no TiO2 industry in Indonesia.
Adsorption of Methylene Blue Dyes Using Pectin Membrane
Authors: Hastuti Budi , Nur Afifah Siti , Mulyani Bakti , Susilowati Endang 
Published: August 2020

Abstract
Environmental pollution caused by methylene blue textile dyes is very dangerous for the aquatic environment and human health. To overcome this problem, various adsorbents have been developed for the processing of methylene blue liquid waste. This aim of this research is to know the ability of pectin membrane toward methylene blue dyes. Pectin is a biomaterial isolated from the plant cell walls. Pectin is an anionic polymer, many contain active groups which able to bind positive ions of methylene blue. This method of this research is an experimental method in the laboratory. Pectin adsorbent membrane was made by dissolving of pectin into a 5% acetic acid solution. The optimal condition of the adsorption of methylene blue by pectin membrane was determine. The functional groups of pectin membranes were analyzed by infra red spectroscopy. The adsorption of methylene blue was analysis by using Ultraviolet-Visible Spectroscopy. The characterization of FTIR showed that pectin membranes have carboxyl and hydroxyl active groups. The results showed that the optimum condition of the adsorption process of methylene blue dye was within pH 4 with adsorption capacity of 0.75 mg/g and 60 minutes of contact time with adsorption capacity 17.64 mg/g. The optimum adsorption capacity of pectin membranes in adsorbing methylene blue was 19.39 mg /g
Implementation of Green Chemistry-Based Electrolysis Learning Media to Develop Higher Order Thinking Ability
Authors: Subarkah C Z , Trisnawati A , Sundari C D D , Malik A 
Published: August 2020

Abstract
In this paper, a green chemistry-based microscale kit and worksheets were made and implemented to develop higher-order thinking ability of students on electrolysis concept. The method used in this research was an experimental method with one-shot case study model implemented to the second-semester chemistry education students studying electrolysis. The ability to think at higher level, i.e. ability to analyze, evaluate, and create, were measured by referring to the revised Bloom taxonomy. The results showed that the average score achieved was 77 (categorize as good) for the ability to analyze, 82 (categorize as excellent) for the ability to evaluate, and 76 (categorize as good) for the ability to create. The as made learning media in the form of micro-scale kit and worksheet were able to develop higher-order thinking ability.
Mental Model of Prospective Teachers on Structure and Properties Correlation of Organic Compounds
Authors: Suja I W , Redhana I W , Sudria I B N 
Published: August 2020

Abstract
This study aims to determine the profile of prospective teachers’ mental models on the correlation of structure and properties of organic compounds before and after learning by implementing the TripleChem learning model. Subjects were students of the Chemistry Education Department of Ganesha University of Education, who are taking courses in Organic Chemistry I in 2018/2019. The subjects of the study were 22 people. Data were collected through two tier achievement test, consists content part (multiple choice) and reason (description). The data were analyzed descriptively. The results showed the mental models of prospective teachers before learning only 1.36% classified as a conceptual model. After learning by implementing TripleChem learning models, conceptual models increased to reach 62.73%. The students’ alternative mental models before and after the study, including specific misconceptions (21.82% and 8.64%), and partially correct (31.36% and 28.64%). The data show that the TripleChem learning model can construct chemistry mental model of prospective teachers on the correlation of structure and properties of organic compounds.
Analysis of Student Chemistry Learning Difficulties on Buffer Solution at SMA Negeri 2 Banjar Buleleng Bali
Authors: Sanjiwani N L I , Muderawan I W , Sudiana I K 
Published: August 2020

Abstract
This research aims to describe and explain students’ learning difficulties in chemistry, the distribution of students’ learning difficulties, and the causative factors of students’ learning difficulties to understand the topic of buffer solution at SMA Negeri 2 Banjar. The data sources for this research were 154 students from all class XI MIA and one chemistry teacher at SMA Negeri 2 Banjar Buleleng Bali. The research method used a quantitative and qualitative method. Quantitative methods are used to collect data on student learning difficulties by using tests and the factors that cause learning difficulties using a questionnaire, while qualitative methods are used to collect data on factors that cause learning difficulties using observation and interview guidelines. Data were analyzed descriptively by grouping students’ learning difficulties into five types includes not difficult, less difficult, quite difficult, difficult, and very difficult. The result of this research showed that students have a difficulty in learning chemistry to understand of buffer solution topic. (1) The students’ learning difficulties on buffer solution topic was ranged between less difficult until very difficult. (2) The distribution and level of student learning difficulties in indicators explaining the definition of buffer solution, analyzing the constituent components of buffer solution, determining buffer and non-buffer solution, calculating pH of acid and base buffer solution, calculating pH of a buffer solution by adding few amount of acid or base or dilution, and explaining the function of buffer solution in the body of living creatures, are difficult enough (44,97%), difficult (74,57%), less difficult (31,66%), difficult enough (43,51%), very difficult (81,82%), and difficult enough (36,36%), respectively. (3) Internal factor that caused learning difficulties is less understanding toward supporting concepts of buffer solution topics and buffer solution concept, the lack of student’s ability in mathematics, less learning interest and motivation toward chemistry. The external factor that caused learning difficulties is teacher’s teaching method, negative effect from friend at the same age, and less conducive learning conditions and times.
Antibacterial and Toxicity Activities Itchy Leaves (Laportea decumana, Roxb. Wedd) Extract
Authors: Simaremare E S , Gunawan E , Yarangga I , Satya M D , Yabansabra Y R 
Published: August 2020

AbstractItchy leaves or stingging nettle have been used as medicinal plants in various countries even in Indonesia. Papuans useLaportea decumana(Roxb)Weddas traditional medicines for local people as an anti-fatigue, anti-stiff and anti-fatigue drug. The purpose of this study was to determine the antibacterial and toxicity of theL. decumanafraction. Samples were taken from Waibron and Serui, Papua Indonesia. The samples were determined at the Center for Biodiversity Development, Papua State University, Manokwari, West Papua.L. decumanaleaf was made in the powder of simplicia, extracted with ethanol then fractionated using three solvents namely n-hexane, ethyl acetate, and ethanol. Extracts and fractions were tested for antibacterial against bacteria and cytotoxics test. The results showed that theL. decumanafraction had activity antibacterial forE. coliandS. aureusbacteria.. The toxicity test showed that fraction n-hexane and ethyl acetate was toxic while ethanol was not toxic.
The Utilization Of Useful Plant Species Based On Socio-Cultural Of Tenganan Pegringsingan Bali Aga Village, District Of Karangasem, Bali
Authors: Wijana Nyoman , Gusti Agung Nyoman Setiawan I 
Published: August 2020

Abstract
The purposes of this research were to know the composition of useful plant species and their utilization by the community based on socio cultural of Tenganan Pegringsingan Bali Aga Village. This research was an explorative research. The location of this research was in Bukit Kangin, Tenganan Pengringsingan Village, District of Karangasem. There were two kinds of population in this research; they were the plant vegetation and the community of Tenganan Pegringsingan Village. The plant vegetation was all of the plant species in the forest area of Bukit Kangin. Meanwhile, the social culture population was all of the Tenganan Pegringsingan people. The vegetation samples of this research were all the plant species covered by the 100 squares with size 20×20 m2. Meanwhile, the social culture samples were: The Village Officials (5 pax), The Traditional Village Officials (5 pax), The Community Figures (10 pax), Shamans (2 pax), Offering Artisan (2 pax), and The General Community Members (20 pax). The total sample were 44 persons. The data retrieval of this study was using square method. The square placement was done by using systematic sampling technique [11], [12], [13], [14] [15]. The interview, observation and questionnaires were used to retrieve socio-cultural data [16], [17]. Furthermore, the data were analized descriptively. The results of this research were: 1) There were 77 plants species in Bukit Kangin, Tenganan Pegringsingan Village, Sub-District of Manggis, District of Karangasem. Those 77 species on the data were included into 40 families with total of 2.574 individuals; 2) There were 46 species out of the 77 plant species in Bukit Kangin classified as useful for religious offerings (Hindu), medications, food, housing, clothing and industrial needs. For more detail of their utilization, it can be summarized as follows: for religious offerings (Hindu) there were 29 plants species (35.80%), for medications there were 18 plants species (27.70%), for food there were 17 plants species (20.99%), for housing there were 13 plants species (16.05%), for clothing and industrial needs there were 2 plants species; and 3) Based on the category of the plant organs/parts utilization can be summarized as follow leaves utilization were 23 plants species (32.40%), stem utilization were 18 plants species (25.35%), fruits utilization were 22 species (30.99%), flowers utilization were 4 species (5.64%), roots and seeds utilization were 2 plant species (2.81%). It could be recommended a further more specific and in-depth study on the utilization of those plant species is needed to be done.
Conflicting Or Synergistic Interaction Between Tourism And Marine Protected Areas In Lembongan Island
Authors: Prasetia I N D , Supriharyono  , Anggoro S , Sya’rani L 
Published: August 2020

AbstractLembongan Island designted as marine protected areas with the Decree of the Minister of Marine Affairs and Fisheries of the Republic of Indonesia Number 24 concerning the Nusa Penida Marine Protected Area of Klungkung Regency in the Province of Bali in 2014. The conservation area is utilized for marine tourism, sustainable fishery, environmentally-friendly aquaculture, social economics research and development, and other sustainable marine resources utilization. Lembongan Island has coral reefs, mangrove forests, white sand, and beaches are a major attraction for tourists. An increase in the number of tourist visits has a direct or indirect impact on coral reef ecosystems. This study aims to determine the relationship between tourism activities and coral reef ecosystems. the study was conducted on Lembongan Island from 2015 to 2018. The study used the manta tow survey method, line itercept transect, questionnaires, interviews and analyzed using SWOT. Research shows that tourism activities have the effect of reducing the quantity and quality of coral reef ecosystems. Co-management of coral reef management by involving all stakeholders can minimize the decline in the quantity and quality of coral reef ecosystems.
Roles Model Of Teachers In Facilitating Students Learning Viewed From Constructivist Theories Of Learning
Authors: Subagia I W 
Published: August 2020

Abstract
Human learning has been understood as a complex process because human learning involves not only physical senses, but also cognitive processes. This paper aimed at describing and explaining teacher’s role model in facilitating students learning. The description and explanation were developed based on constructivist learning theories which explains learning as the process of construction of knowledge by individual student or learner in respond to new learning experiences. The discussion results described three different roles of teacher in conjunction to the characteristics of students’ response in learning process. The characteristic of students can be classified into three, namely excited students, unresponsive students, and struggled students. The roles of the teacher in respond to the characteristic of the students are as a learning supporter for excited students, as a learning motivator for unresponsive students, and as a learning model for struggled students. These roles facilitate all students to learn joyfully and meaningfully through cycles of learning involving assimilation, accommodation, and equilibration processes.
Effective production of multifunctional magnetic-sensitive biomaterial by an extrusion-based additive manufacturing technique
Authors: Rodrigues A F M , Torres P M C , Barros M J S , Presa R , Ribeiro N , Abrantes J C C , Belo J H , Amaral J S , Amaral V S , Bañobre-López M , Bettencourt A , Sousa A , Olhero S M 
Published: August 2020

Abstract
A calcium phosphate (CaP)-based scaffold used as synthetic bone grafts, which smartly combines precise dimensions, controlled porosity and therapeutic functions, presents benefits beyond those offered by conventional practices, although its fabrication is still a challenge. The sintering step normally required to improve the strength of the ceramic scaffolds precludes the addition of any biomolecules or functional particles before this stage.
This study presents a proof of concept of multifunctional CaP-based scaffolds, fabricated by additive manufacturing from an innovative ink composition, with potential for bone regeneration, cancer treatment by local magnetic hyperthermia and drug delivery platforms. Highly loaded inks comprising iron-doped hydroxyapatite and β-tricalcium phosphate powders suspended in a chitosan-based solution, in the presence of levofloxacin (LEV) as model drug and magnetic nanoparticles (MNP), were developed. The sintering step was removed from the production process, and the integrity of the printed scaffolds was assured by the polymerization capacity of the ink composite, using genipin as a crosslinking agent. The effects of MNP and LEV on the inks’ rheological properties, as well as on the mechanical and structural behaviour of non-doped and iron-doped scaffolds, were evaluated. Magnetic and magneto-thermal response, drug delivery and biological performance, such as cell proliferation in the absence and presence of an applied magnetic field, were also assessed. The addition of a constant amount of MNP in the iron-doped and non-doped CaP-based inks enhances their magnetic response and induction heating, with these effects more pronounced for the iron-doped CaP-based ink. These results suggest a synergistic effect between the iron-doped CaP-based powders and the MNP due to ferro/ferrimagnetic interactions. Furthermore, the iron presence enhances human mesenchymal stem cell metabolic activity and proliferation.
Particulate dominance of organic carbon mobilization from thaw slumps on the Peel Plateau, NT: Quantification and implications for stream systems and permafrost carbon release
Authors: Shakil S , Tank S E , Kokelj S V , Vonk J E , Zolkos S 
Published: August 2020

Abstract
Climate change is increasing the frequency and intensity of thermokarst, and accelerating the delivery of terrestrial organic material from previously sequestered sources to aquatic systems, where it is subject to further biochemical alteration. Rapid climate change in the glacially conditioned ice-rich and ice-marginal terrain of the Peel Plateau, western Canada, is accelerating thaw-driven mass wasting in the form of retrogressive thaw slumps, which are rapidly increasing in area, volume and thickness of permafrost thawed. Despite major perturbation of downstream sedimentary and geochemical fluxes, few studies have examined changes in flux and composition of particulate organic carbon (POC) in streams and rivers as a result of permafrost thaw. Here we show that the orders of magnitude increase in total organic carbon, nitrogen, and phosphorus mobilized to streams from thaw slumps on the Peel Plateau is almost entirely due to POC and associated particulate nitrogen and phosphorus release. Slump-mobilized POC is compositionally distinct from its dissolved counterpart and appears to contain relatively greater amounts of degraded organic matter, as inferred from base-extracted fluorescence of particulate organic matter. Thus, slump-mobilized POC is potentially more recalcitrant than POC present in non-slump affected stream networks. Furthermore a substantial portion of POC mobilized from thaw slumps will be constrained within primary sediment stores in valley bottoms, where net accumulation is currently exceeding net erosion, resulting in century to millennial scale sequestration of thermokarst-mobilized POC. This study highlights the pressing need for better knowledge of sedimentary cascades, mobilization, and storage reservoirs in slump-affected streams, and baseline assessments of the biodegradability of POC and cycling of particulate nutrients within a sedimentary cascade framework. Explicit incorporation of POC dynamics into our understanding of land-water carbon mobilization in the face of permafrost thaw is critical for understanding implications of thermokarst for regional carbon cycling and fluvial ecosystems.
TiO2-(Zn1/3Nb2/3)O2-ZrO2microwave dielectric ceramics with near-zero temperature coefficient of resonant frequency
Authors: Wang Geng , Fu Qiuyun , Zhang Lu 
Published: August 2020

Abstract(56.33-x)TiO2-x(Zn1/3Nb2/3)O2-43.67ZrO2(x = 2.60-37.66) ceramics with 0.5%wt CuO addition were prepared by the mixed metal oxide route. Effects of sintering temperature were investigated on the sintering behavior and microwave dielectric properties of ceramics. For all ceramics with x = 2.60-37.66, the optimal sintering temperature range was determined to be around 1280 °C. XRD analysis showed that the main crystalline phase of ceramics sintered at 1280 °C changed from ZrTiO4type at x = 2.60-30.20 to ZrTi2O6type at x = 30.20-37.66. In addition to the main crystalline phase, trace amounts of secondary phases ZrO2and ZnCuTiO4were also observed from SEM and EDS analysis for all ceramics. The permittivity decreased with the increasing x in the range of x = 2.60-30.20 and then remained stable at x = 30.20-37.66, corresponding to the density and covalency bond due to the substitution of (Zn1/3Nb2/3)4+for Ti4+and phase transition at x = 30.20. Furthermore, it was surprisingly found that the temperature coefficient of resonant frequency was near-zero (τf= -9.2 to +9.9 ppm/°C) in a very wide range of x = 10.80-30.20.
Fatigue life extension of 42CrMo high-strength steel and its micro strengthening mechanism under laser shock peening
Authors: Sun Rujian , Huang Weiqing , Cao Ziwen , Che Zhigang , Zou Shikun , Wu Junfeng 
Published: August 2020

Abstract
Laser shock peening is an advanced surface treatment technique in improving the fatigue properties of metallic components. In this study, the effects of different laser shock peening regions on the high cycle fatigue of 42CrMo high-strength steel were investigated. Surface deformation, residual stress, and microhardness were analyzed, and microstructural evolution including grain size, boundary distribution, and misorientation was examined. Results show that peening the specimen with both surfaces and sides resulted in a better fatigue life than only peening the surface. The compressive residual stress introduced in both the surfaces and sides provided a higher resistance for fatigue initiation. In addition, the increase of low angle grain boundary accounted for the micro strengthening mechanism for the fatigue life extension.