Optimizing the Tyrosinase Inhibitory and Antioxidant Activity of Mango Seed Kernels with a Response Surface Methodology

This study describes the optimization of polyphenol extraction from mango seed kernels by using response surface methodology (RSM). In the solid-to-liquid selection, the extraction yield, total phenolic content (TPC), antioxidant activity, and tyrosinase inhibitory activity are all significantly increased with a decrease in the solid-to-liquid ratio (P?<?0.05). Between the Nam-Dok-Mai kernel (NDK) and the Tong-Dam kernel (TDK), the TDK was chosen for RSM with a fixed ratio of 1:30 solid-to-liquid. The variables in the independent processing were the concentrations of ethanol, the temperature, and the time applied to RSM. Ethanol concentration, temperature, and duration had significant individual and interactive effects on phenolic yield and antioxidant activities (P?<?0.05). The optimized condition that maximized the extraction yields, TPC, and antioxidant activities from TDK was an ethanol concentration of 62 %, a temperature of 63 °C, and a duration of 150 min. The obtained and validated optimized model could be used to describe the effect of these variables on the extraction of phenolic compounds from mango seed kernels.     

Development of a practical Monte Carlo based fuel management system for the Penn State University Breazeale Research Reactor (PSBR)

A practical fuel management system for the he Pennsylvania State University Breazeale Research Reactor (PSBR) based on the advanced Monte Carlo methodology was developed from the existing fuel management tool in this research. Several modeling improvements were implemented to the old system. The improved fuel management system can now utilize the burnup dependent cross section libraries generated specifically for PSBR fuel and it is also able to update the cross sections of these libraries by the Monte Carlo calculation automatically. Considerations were given to balance the computation time and the accuracy of the cross section update. Thus, certain types of a limited number of isotopes, which are considered “important”, are calculated and updated by the scheme. Moreover, the depletion algorithm of the existing fuel management tool was replaced from the predictor only to the predictor-corrector depletion scheme to account for burnup spectrum changes during the burnup step more accurately. An intermediate verification of the fuel management system was performed to assess the correctness of the newly implemented schemes against HELIOS. It was found that the agreement of both codes is good when the same energy released per fission (Q values) is used. Furthermore, to be able to model the reactor at various temperatures, the fuel management tool is able to utilize automatically the continuous cross sections generated at different temperatures. Other additional useful capabilities were also added to the fuel management tool to make it easy to use and be practical. As part of the development, a hybrid nodal diffusion/Monte Carlo calculation was devised to speed up the Monte Carlo calculation by providing more converged initial source distribution for the Monte Carlo calculation from the nodal diffusion calculation. Finally, the fuel management system was validated against the measured data using several actual PSBR core loadings. The agreement of the predicted core excess reactivities and the measured values is found to be good considering the measurement uncertainties.     

Heterogeneous catalysis of transesterification of soybean oil using KI/mesoporous silica

Heterogeneous catalysis of transesterification using KI/mesoporous silica catalyst was utilized to produce biodiesel from soybean oil and methanol. The effects of reaction temperature, percentage of KI loading, reaction time, and amount of catalyst on the conversion to methyl ester were studied. The results showed that increasing reaction temperature, KI loading and reaction time can enhance the conversion. The optimum condition was the reaction temperature at 70 °C, 15 wt.% of KI, a reaction time of 8 h., and a catalyst amount of 5.0% by weight of the oil which yielded 90.09% of the conversion. The fuel properties of biodiesel from the optimum condition were tested and found that only viscosity showed over standard. However, the high viscosity can be reduced by separation of non-reacting soybean oil.     

Properties of gelatin films from giant catfish skin and bovine bone: a comparative study

Edible films were prepared from the gelatin of farmed giant catfish skin (GC) (Pangasianodon gigas), bovine bone gelatin (BB) and their combination. The physical, mechanical, thermal and chemical properties of the resulting films were characterized and compared. The molecular weight distributions of the giant catfish skin gelatin-containing samples had high quantities of α-chains, β-components and high molecular weight cross-links. The bovine bone gelatin-containing samples showed low contents of major bands with high degradation band components. The GC films had higher water activity (0.45) and mechanical properties [tensile strength: TS 41 MPa and elongation at break: EAB 34 (%)] but lower thickness (38 μm) and water vapor permeability than those of BB films. The lowest light transmission (200–800 nm) and film transparency (3.34) were found in the GC films. However, the color attribute (L, a and b) of BB films was closer to the low-density polyethylene commercial film (ΔE 1.2). The highest value of film and protein solubility (100%) was found in BB film, while the lowest value (41–56%) was found in GC film. The GC films showed the most compact, smooth and continuous surface without porous structures, which corresponds to the greater properties of films.     

MCOR – Monte Carlo depletion code for reference LWR calculations

The MCOR (MCnp-kORigen) code system is a Monte Carlo based depletion system for reference fuel assembly and core calculations. The MCOR code is designed as an interfacing code that provides depletion capability to the LANL Monte Carlo code by coupling two codes: MCNP5 with the AREVA NP depletion code, KORIGEN. The physical quality of both codes is unchanged.     

Accuracy evaluation of pin exposure calculations in current LWR core design codes

The deregulated utility environment and better utilization of fuel assemblies in nuclear power plants has allowed designers to burn fuel assemblies to maximum allowable exposures. Any uncertainties, associated with the technical approach and numerical methods used to perform pin exposure calculations may cause either peak power exposure to exceed the Nuclear Regulatory Commission (NRC) exposure limit or lead to excessive conservatism and thus inefficient fuel utilization. In this work, a Monte Carlo based coupled depletion code (MCNP5/ORIGEN-S) is utilized to provide reference solutions in order to assess the accuracy of pin power and pin exposure reconstruction methods in the current commercial and licensed three-dimensional (3D) nodal Light Water Reactor (LWR) core design codes. The developed at the Pennsylvania State University (PSU) MCNP5/ORIGEN-S coupled depletion code system was validated using measured data from the PSU TRIGA research reactor critical experiments.     

Stability evaluation of ethanol dry reforming on Lanthania‐doped cobalt‐based catalysts for hydrogen‐rich syngas generation

Catalytic stability with time‐on‐stream is an important aspect in ethanol dry reforming (EDR) since catalysts could encounter undesirable deterioration arising from deposited carbon. This work examined the promotional effect of La on 10%Co/Al₂O₃ in terms of activity, stability, and characteristics. Catalysts were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Raman, and X‐ray photoelectron spectroscopy (XPS) measurements whilst catalytic EDR performance of La‐promoted and unpromoted 10%Co/Al₂O₃ prepared via wet impregnation technique was investigated at 973 K for 72 h using a stoichiometric feed ratio (C₂H₅OH/CO₂ = 1/1). La promoter substantially enhanced both metal dispersion and metal surface area from 0.11% to 0.64% and 0.08 to 0.43 m² g^?1, respectively. Ethanol and CO₂ conversions appeared to be stable within 50 to 72 h after experiencing an initial activity drop. The conversion of C₂H₅OH and CO₂ for La‐promoted catalyst was about 1.65 and 1.34 times greater than unpromoted counterpart in this order. The carbonaceous deposition was considerably decreased from 55.6% to 36.8% with La promotion due to La₂O₂CO₃ intermediate formation. Additionally, 3%La‐10%Co/Al₂O₃ possessed greater oxygen vacancies acting as active sites for CO₂ adsorption and hence increasing carbon gasification. Even though graphitic and filamentous carbons were formed on used catalyst surface, La‐addition diminished graphite formation and increased the reactiveness of amorphous carbon.     

Gelatinolytic enzymes from Bacillus amyloliquefaciens isolated from fish docks: Characteristics and hydrolytic activity

Fifty-five bacteria with gelatinolytic activity were screened from over 500 isolates obtained from fishing docks in Songkhla, Thailand. Based on 16S rRNA gene sequence analysis, 3 selected strains (K12, O02, and S13) were identified as Bacillus cereus with 99.8% similarity. Three other stains (D10, G02, and H11) were identified as Bacillus amyloliquefaciens with 99.7% similarity. Gelatinolytic enzymes of the D10, G02, and H11 strains were precipitated using ammonium sulfate precipitation, followed by dialysis with an increase in purity between 19-34-fold. Maximal gelatinolytic activities towards fish gelatin were attained at 50°C and pH 7.5. Metallo- and serine-gelatinolytic enzymes were dominant for all 3 strains. All gelatinolytic enzymes showed similar hydrolysis towards fish gelatin to commercial Alcalase, but higher hydrolysis was found in the formers within the first 60 min. Therefore, gelatinolytic enzymes from selected B. amyloliquefaciens strains can be used for production of fish gelatin hydrolysate.     

Determination of perfluorinated compounds (PFCs) in solid and liquid phase river water samples in Chao Phraya River, Thailand

Perfluorinated compounds (PFCs), especially perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are fully fluorinated organic compounds, which have been used in many industrial applications. These chemicals have contaminated surface water all over the world even in developing countries like Thailand. The previous study showed the contamination in Chao Phraya River in 2006 and 2007. The purposes of this field study were to determine the solid and liquid phase of PFCs contamination in Chao Phraya River and to compare the changes of PFC concentration in 2008. Surveys were conducted in the lower reach of Chao Phraya River in the industrialized area. A solid phase extraction (SPE) coupled with HPLC-ESI-MS/MS were used for the analysis for ten PFCs. Ten PFCs were analyzed to identify the contamination in both solid and liquid phases. PFCs were detected in both the solid and liquid phase in every sample. PFOA was the most dominant PFC while PFPA and PFOS were also highly detected in most samples. The average loadings of PFPA, PFOA and PFOS in Chao Phraya River were 94.3, 284.6 and 93.4 g/d, respectively. PFOS concentrations did not show differences between 2006 and 2008. However, PFOA concentrations were higher in 2008/5/26, while comparing other samplings. The ratio of solid:liquid PFPA (2.1:1.0) [(ng/g)/(ng/L)] was lower than PFOA (13.9:1.0) [(ng/g)/(ng/L)] and PFOS (17.6:1.0) [(ng/g)/(ng/L)]. The shorter chain (more hydrophilic) PFC was better to dissolve in water rather than adsorb onto suspended solids. PFOS also showed more potential to attach in the suspended solids than PFOA.