Key Engineering Materials Vol. 949

Abstract: In this paper, we investigate the probability of the charge transfer interaction process from Cu metal to P6 molecule systems using charge transfer rate calculations. The charge transfer rate from donor Cu metal to an acceptor P6 molecule dye is presented with reorientation energy, electronic drive force, and barrier height emphasis on the effects of transfer processes in the Cu/P6 system. Charge transfer flow probability from Cu metal contacts to P6 dye molecule has recently been considered within the perturbation theory method, where the charge transfer rates have been found to be affected by strength coupling and reorientation energy. The charge transfer could be occurred even at large reorientation energy, less driving force energy, and low potential barrier. It requires to reorientation the donor to acceptor energy levels to start the charge transfer. It has been found that the rate of charge transfer processes enhance the flow rate yield of the transfer cross interface dependent on the potential barrier.

Abstract: It has been investigated an Ising ferrimagnet with mixed spin-2 and spin-5/2 and various crystal field parameters on a body-centered cubic lattice. In this research paper, ferrimagnetic compensation temperatures and phase transitions to clarify the characteristic features, in a series of molecular-based magnets AFe^IIFe^III(C₂O₄)₃[A=N(n-C_nH_2n+1)₄, n=3-5] are examined in the Oguchi approximation (OA). The spin crystal domain dependence of compensation behavior acting on ions contain the Oguchi lattice, is mainly studied. It is discovered, specifically, that magnetic anisotropies in the disordered for the two sublattices of the model depend on the negative values of the crystal fields to produce a characteristic ferrimagnetic behavior. For D_A/|J|=-1.5 and D_B/|J|=-5.5, there are two compensation points are induced at an ordered phase(2,-1.5).

Abstract: A theoretical investigation and evolution of the current rate produced in the Fe/molecule system results from charge transport interaction processes. The current flow charge rate properties of Fe metal contact with ZnPc organic sensitizers are investigated and studied based on analytical calculation and a simple quantum scenario model coupled with a semi-empirical continuum energy state. The current flow charge rate is done due to the transition energy, potential interface, driving energy, and coupling coefficient for considering Fe/ ZnPc system. The evolution of current flow charge rate for Fe/ ZnPc system with variety coupling coefficient. Fe/Zn-tri-PcNc-8 sensitized system is studied at room temperature. The flow charge rate of Fe/ ZnPc system results is found to be increasing with decreasing the transition energy and increasing the coupling coefficient. Potential at the interface is estimated according to energy absorption and transition energy. Our data shows that, at high polarity, the current flow charge rate is a smooth shift with propanol solvent compared with methanol, whereas at a higher transition energy for a system with methanol solvent. It is found that the Fe/ ZnPc system with propanol solvent has good mobility of electrons compared with methanol solvent.

Abstract: Research on Concentration of Heavy Metals (As, Cd, Li, Ni, Pb, Ti) in tilapia fish (Oreochromis sp.) from Sleman and Bantul and The Food Safety Level was studied. The aims of this research were to determine heavy metals concentration in tilapia fish, discover the correlations between metal and morphometric factors in tilapia fish, and determine food safety level intake of tilapia fish to be consumed per week. Determining metal concentrations in tilapia fish were using ICP-MS instrument, which the samples were dried using freeze dryer and destructed using microwave digester. The concentrations obtained were utilized to determine correlations between metal and morphometric factors, and measure Maximum Weekly Intake, Maximum Tolerable Intake, and food safety level intake per week. Based on research, the results showed metal accumulation in tilapia fish (Oreochromis sp.) from the largest to the smallest value for Bantul area was Ti, As, Ni, Pb, Li, Cd and for Sleman was Ti, As, Ni, Pb, Cd, Li. Concentration of As metal shows higher content than the threshold limit standards. Heavy metal accumulation was found in tilapia body that has positive and negative correlations between As metal and morphometrics in tilapia fish. Based on the measurement, food safety level intake tilapia fish for one adult is 1096 fish/week.

Abstract: The problem in poultry farms is the odorous pollution (ammonia emission) caused by amino acid deamination from undegraded residual protein at the excreta. This study was aimed to determine the effect of fermented tobacco leaves (FTL) on the ammonia gas emission reduction in chicken layer excreta. The research was conducted based on 4 different levels of FTL addition in excreta 0 (blank), 1, 3, and 5% of the total weight of manure in 3 replications, respectively. One-way ANOVA was used to analyze the data. This research showed that microbial from FTL can grow on both agar and the liquid medium with the stationary phase starting at 9 h of incubation. The addition of FTL can reduce the ammonia emission from chicken layer excreta starting at 5 to 6 day. The highest reduction of final ammonia emission on the six-day occurred at 5% treatment and was observed at 91.30±8.40 ppm. Therefore, it can be concluded that FTL has a potential microorganism for mitigating ammonia emission in the chicken layer excreta. Thus, the application so giving 1% of FTL was efficient enough to reduce the daily ammonia production in the chicken layer excreta.

Abstract: Chili is an agricultural product that is used as a spicy seasoning because it produces a hot effect with striking color and can be processed into various products, such as chili paste. However, it was found that some sellers misused the harmful Rhodamine B (RB) dye in chili paste to maintain the color in order to maximize profits without considering the health impact of consumers. In this study, a method was developed to predict RB in chili paste samples non-destructively using the VIS-NIR instrument combined with the Partial Least Square Regression (PLS) chemometric method to build a calibration model to measure RB content. Red curly chilies in good condition without blemishes were washed and then ground into chili paste products as samples in this study. The samples were divided into four variations of RB concentration, namely 0 ppm, 250 ppm, 500 ppm, and 1000 ppm. The chili paste spectra were acquired at a wavelength of 450-950 nm and several pre-treatments spectra were performed. The best calibration model that can be generated using pre-treatment multiplicative scatter correction (MSC) has a calibration value of R2 of 0.96, SEC of 70.69, and RPD of 4.52. This shows that a non-destructive method for predicting RhB concentrations in chili paste using VIS-NIR spectroscopy combined with chemometric analysis produces a good measurement method for screening applications.

Abstract: In a batch system, The Cu(II) preconcentration parameters were optimized using chitosan-crosslinked dialdehyde carboxymethyl cellulose (CS-DCMC). The experiment was started with the oxidation of carboxymethyl cellulose by periodate to form DCMC. The CS-DCMC adsorbent was then prepared with a mass ratio of CS-DCMC=1:1. The adsorbent is characterized by FTIR for functional group analysis and SEM-EDX for morphological analysis and the percentage of elements in CS-DCMC adsorbent. In the optimization of preconcentration parameters, the optimal adsorption, desorption, and enrichment factors were obtained at pH 4, adsorbent mass of 90 mg, adsorption time of 95 min, Cu(II) concentrations of 7 mg/L, and Na₂EDTA 1 M. The application of CS-DCMC on wastewater containing Cu(II) under optimal conditions gave good results. Wastewater containing Cu(II) 0.1 mg/L can be concentrated to 0.53 mg/L with an enrichment factor of 5.26 times, 0.2 mg/L Cu(II) can be concentrated to 1.08 mg/L with an enrichment factor of 5.40 times, and 0.3 mg/L Cu(II) can be concentrated to 1.68 mg/L with an enrichment factor of 5.59 times. The enrichment factor obtained is almost close to the theoretical enrichment factor of 6 times.

Abstract: Selective removal of silicon might open-up the possibility of reusing silicon-contaminated spent catalyst. Unfortunately, study regarding this topic is still scarce. The effect of important parameters such as leaching treatment time and temperature was investigated, and the process conditions were optimized using response surface methodology (RSM) based on central composite design (CCD). Based on analysis of variance (ANOVA) results, leaching treatment time was found to be the most significant parameter, followed by temperature. Higher temperature and longer treatment time were satisfactorily enough for efficient silicon leaching from spent catalyst. The obtained quadratic model (R² = 0.995) shows a good correlation between the predicted values and experimental data. The optimum condition for silicon leaching was identified to be a temperature of 213.3°C and a treatment time of 5.83 hours.

Abstract: Mixed oxide of titanium dioxide was synthesized by adding SnO₂ and CeO₂ through a precipitation method for the degradation of methylene blue (MB) under visible light. The as-prepared was dried and calcined at various temperatures, i.e. 450-750 °C. The calcined products were characterized by XRD, DRUV, and FTIR. The effect of calcination temperature was studied on the photodegradation of MB under visible light. The photocatalytic activity showed that calcined photocatalytic at 650 °C shows the lowest bandgap energy and the highest photocatalytic activity in the decomposition of methylene blue under visible light.