Materials Science Forum Vol. 1044

Abstract: Nanoparticles of Merapi volcanic ash and phosphate-solubilizing fungi were expected to function as ameliorants in improving some Inceptisols characteristics. Nanoparticles of volcanic ash were used in accelerating and streamlining the chemical reaction in the soil. Phosphate-solubilizing fungi were expected to assist the process of several soil reactions. The aim of the research was to improve some chemical characteristics like available P, cation exchange capacity, Fe, and Zn content of Inceptisols in Cilembu Village, Sumedang District, West Java Province, Indonesia. The research used a complete randomized experimental design in factorial with two factors. The first factor was the nanoparticle of Merapi volcanic ash consisted of four doses on soil weight percentage (0%, 2%, 4%, and 6%). The second factor was phosphate-solubilizing fungi consisted of two doses (without and 10 g.kg^-1). The volcanic ash was collected from Mt. Merapi, Central Java, after the eruption of November 2010 and kept in the Laboratory of Soil Physics and Conservation in Faculty of Agriculture, Universitas Padjadjaran. The nanoparticle of volcanic ash was processed at Nanotechnology and Graphene Research Centre, Universitas Padjadjaran. The phosphate-solubilizing fungi were isolated from Inceptisols in Soil Microbiology Laboratory, Universitas Padjadjaran. These treatments were combined and mixed with soils and incubated for three months. Every one month during those three months of the incubation period, some soils were taken to be analyzed of available P, cation exchange capacity (CEC), available Fe, and available Zn. The result showed that there was no interaction between the nanoparticle of Merapi volcanic ash and phosphate-solubilizing fungi to parameters investigated except the CEC after two months of incubation. There was an effect of nanoparticle volcanic ash and phosphate-solubilizing fungi individually to available Fe dan Zn. There was a trend of increasing available P, and CEC and decreasing available Fe and Zn by the longer period of incubation.

Abstract: Cilembu's Inceptisols have great potential for agriculture. However, land management has several limiting factors: the available phosphate content, cation exchange capacity (CEC), and low population of functional soil organisms. Rock phosphate is a natural material that can increase the availability of P nutrient. Application of rock phosphate as an ameliorant in nanoparticle size and inoculation of phosphate-solubilizing fungi (PSF) is a strategy that can be implemented to address the Inceptisols constraints. However, the dynamic of chemical and biological characteristics of Cilembu Inceptisols due to amendment of phosphate rock nanoparticle (PRNp) and phosphate solubilizing fungi (PSF) inoculation is not yet understood clearly. To know the dynamics of the chemical and biological properties of the soil due to the treatment of these materials is an essential aspect for strategy and planning in its proper application to improve the properties of Inceptisols. The completely randomized design (CRD) was used in this study, with a factorial pattern, consisting of the first factor being the amendment of rock phosphate nanoparticle and the second factor being the PSF inoculation. The observation was carried out in a month interval, with a three-month incubation. The result showed there was no interaction between phosphate rock nanoparticle amendment and PSF inoculation on pH-H₂O, available P, CEC, and abundance of PSF population. The independent effect showed that a characteristic pattern of pH and available P values during two months of observation was increasing by PRNp amendment. Meanwhile, inoculation of PSF did not increase soil pH and P-available. The value of CEC and the population of PSF did not increase significantly during the three-month incubation. The dose of phosphate rock nanoparticle 2% (wt/wt) increased the highest available P.

Abstract: Nanoparticle has been used in agricultural practices such as soil ameliorant. Nanoparticle of volcanic ash and biofertilizer were applied to improve some soil characteristics of Inceptisols. The objective of this research was to optimize the benefit of nanoparticle of volcanic ash and biofertilizer in reducing soil acidity, increasing organic carbon content, and increasing basic cations of Inceptisols. Volcanic ash was obtained from the eruption of Mt. Merapi in Central Java. Nanoparticle was grinded in Nanotechnology and Graphene Research Center, Universitas Padjadjaran. Phosphate solubilizing fungi was used as biofertilizer, isolated in Soil Microbiology Laboratory, Universitas Padjadjaran. A two factors randomized experimental design was used in this research. Nanoparticle of volcanic ash was used as first factor (four levels: 0%, 2%, 4% and 6% of soil weight percentages). Biofertilizer was used as second factor (two levels: 0 and 10 g.kg^-1). These two treatments were combined and mixed evenly and incubated for three months in field condition. Every month during those three months a few soil samples were taken to analyze the change of soil characteristics. The results showed that the treatments increased organic carbon content and potassium basic cation but had no effect to soil acidity.

Abstract: Intensive agricultural cultivation on Cilembu’s Inceptisols has become several soil properties problem for crop production. Nanoparticle phosphate rock and phosphate solubilizing fungi have ability to increase some soil properties content. The research aimed to observe the effect of nanoparticle phosphate rock and phosphate solubilizing fungi on soil P-potential, P-retention, C-organic and base saturation on Cilembu’s Inceptisols. The experiment arranged in Completely Randomized Design. The nanoparticle phosphate rock consisted of 4 levels. The phosphate solubilizing fungi consisted of 2 levels, and 2 replication. Soil P-Potential, P-Retention, C-organic, and Base Saturation were observed. The factors was observed after one month incubation on soil. Results showed that there were an interaction between nanoparticle phosphate rock and phosphate solubilizing fungi on the C-organic after one month incubation. Nanoparticle phosphate rock had affected on C-organic, P-potential and base saturation significantly, but had not affected on P-retention. Utilization of phosphate solubilizing fungi as soil ameliorant had affected significantly on P-potential and C-organic, but had not affected on P-retention and base saturation. Nanoparticle phosphate rock with a dose of 6% had the best effect on increase P-potential and base saturation

Abstract: The process of final disposal of industrial wastewater is an important issue to avoid contamination. Photocatalyst technology can be a solution to waste control by degrading organic pollutants. The synthesis process of TiO₂ catalyst immobilized with supporting materials has been proven more efficient in photocatalyst activation. This gives a high UV adsorption power and does not require further handling of the final purification process because it does not produce a catalyst suspension. Immobilization methods are simplest but still produce high efficiency, namely, the thermal milling method and the sol-gel method. Both methods can produce 97% efficiency. Immobilization using thermal milling can take quickly and only through one step but requires a long time in the degradation process. Besides, immobilization using the sol-gel method requires several steps, but the process of degradation is fast. The method used must be by the type of support material, the pollutants to be degraded, and the operating system like coating time. This paper focuses on the immobilization method suitable to support materials to maximize the degradation process.

Abstract: Calcium hydroxide (Ca(OH)₂ has been recently synthesized from natural Indonesian limestone to be used as an intracanal medicament for root canal infection. Ca(OH)₂ is applied into the infected root canal in a non-setting paste form to release calcium and hydroxyl ions which elevates the pH and provide an antimicrobial effect to pathogenic bacteria. To form an injectable paste, Ca(OH)₂ powder has to be mixed with a proper solvent to produce optimal consistency, ion dissociation, and maintain its property as a non-set material. Solvent is an important factor affecting ion dissociation and preserving its non-setting paste condition. The aim of this study is to synthesize Ca(OH)₂ powder from Indonesian limestone, and evaluate the setting time of Ca(OH)₂ paste from mixture of Ca(OH)₂ powder synthesized from Indonesian limestone (limestone Ca(OH)₂) with various solvent, to evaluate which solvent serve best to prevent the Ca(OH)₂ paste from setting, to form an ideal paste be used as an intracanal medicament. This study consists of 5 groups (n=5); commercially Ca(OH)₂ paste (Calcipex II) as positive control, Ca(OH)₂ powder (Merck) + distilled water as negative control, limestone Ca(OH)₂ powder + natrium carboxy methylcellulose (Na CMC) as group 1, limestone Ca(OH)₂ powder + propylene glycol (PG) as group 2, and limestone Ca(OH)₂ powder + polyethylene glycol (PEG) as group 3. Setting time evaluation was measured according to ISO 9917 by vicat needle in 37°C to mimic the physiological body condition. Results were analyzed by One Way Anova test and Post Hoc Tukey test. The result of this study showed that the setting time of Ca(OH)₂ paste mixed with Na CMC solvent was 1:04 hours, PG 72:15 hours, and PEG did not harden until 7 days of observation. PEG is a hygroscopic high viscosity solvent, resulting in low and steady molecule interaction, thus prolonged its setting time. From this study it can be concluded that PEG inhibit Ca(OH)₂ setting reaction up to 7 days and might be used as solvent for Ca(OH)₂ paste as intracanal medicament.

Abstract: Recurrent endodontic infections of treated teeth are mainly linked to microbial persistency in the root canal system. Enterococcus faecalis is a bacterium that is often identified in these recurrent infections. Calcium hydroxide (Ca(OH)₂) is a widely used root canal medicament and is now being developed to be produced from natural materials. Ca(OH)₂, which is synthesized from natural limestone from Palimanan, Indonesia, has a structure similar to Ca(OH)_2, which is often used as a root canal medicament. The purpose of this study was to determine the antimicrobial property of Ca(OH)₂ paste synthesized from natural limestone compared to conventional Ca(OH)₂ paste. This study is an in vitro experimental study consists of 3 groups (n=24, namely, conventional Ca(OH)₂ paste, limestone synthesized Ca(OH)₂ paste, and saline as the negative control, for 2 intervals of time and evaluated by Total Plate Counting (TPC) method. Samples were mandibular first premolar root canal prepared by root canal preparation and contaminated with E. faecalis (ATCC 29212). The infected root canals of each group were treated by the medicaments, and samples from the root canals were taken on day 7 (n=4) and 14 (n=4). Results showed that both Ca(OH)₂ groups had antimicrobial activities against E. faecalis. The limestone Ca(OH)₂ paste group had the least amount of bacterial colonies on the 7^th day compared to other groups. In contrast, on the 14^th day, the conventional Ca(OH)₂ paste had the least bacterial colonies. It can be concluded that the Ca(OH)₂ paste synthesized from natural limestone has an antimicrobial effect on E. faecalis, the antimicrobial effect was higher on the 7^th day but decreases on the 14^th day, whereas the conventional Ca(OH)₂ had a higher antimicrobial effect on day 14 compared to day 7. Further studies are expected to improve the long-term antimicrobial effectiveness and sustainability of the natural limestone synthesized Ca(OH)₂ paste.

Abstract: The purpose of this study was to evaluate the effect of weak magnetic fields on the structure and physical properties of chitosan (Ch) membranes. The membranes were prepared by a casting method using chitosan and a solvent of acetic acid. The magnetic field of 1.5 mT is applied during the membrane-forming reaction with administration times of 2, 4, 8, and 12 hours. The membranes formed were named M-2h, M-4h, M-8h, and M-12h, respectively. The chitosan membrane without magnetic fields is used as a control, namely M-0. The structure and physical properties of the membranes were examined using Fourier Transform Infra-Red (FTIR) spectrophotometer, water uptake test, dynamic mechanical analysis (DMA), and X-ray diffraction (XRD). The result showed that the membranes with magnetic fields are thicker compared to the control membrane. FTIR analysis revealed that some peaks of the membranes with magnetic fields shifted to the higher or lower wavenumber with increased or decreased absorption intensity. The membranes become stronger and more flexible; their degree of crystallinity increases as increasing the time of the magnetic fields' application, and their hydrophilicity improved. The membranes' crystal structure becomes more regular, and their degree of crystallinity increases as increasing the time of the application of the magnetic fields; and their mechanical properties such as ultimate tensile strength, tensile modulus, and elongation at break were improved. Those results explain that the structure and physical properties of chitosan membranes were significantly affected by the membrane-forming reaction's magnetic fields.

Abstract: The biocomposites were prepared from chitosan, carragenan and modified tapioca with lauric acid addition. The biocomposite were used as edible film material thus improving the mechanical characteristics. The purpose of this study was to determine the amount of lauric acid addition that produced biocomposites with the best characteristics. This study used experimental method. The different concentration of lauric acid used as the treatment was 0%, 10%, 20%, 30%, 40% from total solid of hydrocolloids materials (w/w). Data were analyzed statistically using the F test (ANOVA test) with confidence level of 95%. The results showed more than 10% addition of lauric acid decreased the value of moisture content, tensile strenght, percent elongation and water vapor transmission but increase thickness, opacity and transparency value. The addition of 10% lauric acid produced biocomposite with the best characteristics according to JIS (Japanese Industrial Standard) which had the moisture content of 42.65%, thickness of 0.047 mm, tensile strength of 13.8 MPa, percent elongation of 29.2%, water vapor transmission rate of 8.5 g/m²/day, opacity 8.9% and transparency 7.5. This research used renewable and biodegradable materials that can be applied to produce edible packaging with the best characteristics and eco-friendly.