Development of a three-part time-of-day electrical energy tariff

This paper presents an analytical technique for determining peak, offpeak and midpeak hours tariffs for various durations of these three periods. The technique considers the existing flat rate tariff, an hourly generation scenario of a utility on an average yearly demand day, the weighted average life time, annutised capital cost and fuel cost of base and peak load plants, and a break even point condition in the utility's revenue. The developed tariff has been applied to 30 representative industrial consumers served by the Bangladesh Power Development Board (BPDB) to estimate the minimum possible shift in consumption pattern and hence corresponding reduction in peak generation capacity requirement as well as peak time load shedding by BPDB. © 1998 John Wiley & Sons, Ltd.     

A novel data-driven methodology for fault detection and dynamic risk assessment

This paper presents a novel methodology for dynamic risk analysis, integrating the multivariate data-based process monitoring and logical dynamic failure prediction model. This concept for dynamic risk analysis is comprised of the fault assessment and dynamic failure prognosis modules. A combination of the naïve Bayes classifier, Bayesian network, and event tree analysis is utilized to manifest the concept. The naïve Bayes classifier is used for fault detection and diagnosis; it also generates a multivariate probability for a fault class in each time-step, which is used for dynamic failure prognosis by different paths a fault can lead a process to failure. The proposed framework has been applied to two process systems: a binary distillation column and the RT 580 experimental setup in four fault scenarios, and it is found the developed technique can effectively monitor the process and predict the failure.     

Synthesis and electrochemical characterization of La0.75Sr0.25Mn0.5Cr0.5−xAlxO3, for IT- and HT-SOFCs

The main emphasis of this work is to create a new perovskite material with three different compositions (La_0.75Sr_0.25Mn_0.5Cr_0.5−xAlxO₃, x = 0.1, 0.2, 0.3) applied in both Intermediate- and High-temperature Solid Oxide Fuel Cells (IT- and HT-SOFCs). Perovskite-type polycrystalline La_0.75Sr_0.25Mn_0.5Cr_0.5−xAl_xO_3−δ (x = 0.1, 0.2, 0.3) powders were synthesized and formed in a single phase structure by a dry chemistry route (standard solid-state reaction method). The effect of Al doping on physicochemical and surface properties has been discovered. The compounds were crystallized in single phase rhombohedral symmetry (R-3C Space. Group). Total conductivity of Al doping in wet 5% H₂ was higher than both dry 5% H₂ and air. The obtained results enhance the electro-catalytic performance and the material conductivity as well, which will be good for anode materials in IT- and HT-SOFCs and the optimum doping is 10%.     

Evaluation of isotopic boron (11B) for the fabrication of low activation Mg11B2 superconductor for next generation fusion magnets

In this study, we analyze the properties of boron isotope (¹¹B)-rich powders from three different sources, that is, American, Cambridge, and Pavezyum, to fabricate the bulk Mg¹¹B₂ superconductors and evaluate their superconducting properties. While ¹¹B-rich powder is an essential precursor to fabricate Mg¹¹B₂ superconductors for fusion magnet applications, the properties of the ¹¹B powder turned out to be critical to determine the quality of the final superconducting product. Therefore, appropriate control of processing conditions is needed to comply with the requirements of the nuclear fusion application. Analysis of the B isotope ratio by accelerator mass spectroscopy and neutron transmission revealed that all three types of powder are enriched with ¹¹B to better than 99 at % quality. In addition, Pavezyum's ¹¹B shows the lowest crystallinity and smallest crystalline domain size as evidenced by the high-resolution X-ray diffractometer and scanning electron microscopy. The chemical states of the boron isotope investigated with near edge X-ray absorption fine structure spectroscopy and X-ray photoemission spectroscopy also reveals that Pavezyum boron has amorphous structure. Mg¹¹B₂ bulks and multi-filamentary (12-filament) wires have been manufactured, sintered at different temperatures and characterized via the transport critical current density. The wire with Pavezyum ¹¹B shows three times higher current carrying capacity at a particular magnetic field compared to the wire using Cambridge ¹¹B and hence, Pavezyum ¹¹B boron has the potential for manufacturing fusion grade Mg¹¹B₂ based magnets. The results of this study demonstrated that Boron powders with higher purity, smaller grain size and lower crystallinity are critical for improving the superconducting and electronic properties of Mg¹¹B₂ samples fabricated from the powder. Thus, the low-neutron-activation Mg¹¹B₂ is possibly an affordable and technically viable candidate to replace NbTi superconductors in the low field poloidal field and correction coils for the next-generation fusion reactors.     

Phytosterol Determination and Method Validation for Selected Nuts and Seeds

A method involving alkali and/or acid hydrolysis of phytosterols followed by trimethylsilyl ether derivatization coupled with GC-FID analysis was validated and applied in the analysis of major phytosterols (campesterol, stigmasterol, β-sitosterol, and Δ⁵-avenasterol) in nuts (n = 7), seeds (n = 9), legumes (n = 2), and grain (n = 1). The acid-labile Δ⁵-avenasterol was extracted with alkaline hydrolysis only before derivatization. Quantification of all phytosterols was done using the computed relative response factor of 5α-cholestane (internal standard). Analyses of internal and external phytosterol standards showed good linearity for all phytosterols (R ² of 0.999); LOD and LOQ of phytosterols were determined to be 0.01–0.12 and 0.04–0.40 mg/100 g, respectively. Repeatability and reproducibility precision analyses showed acceptable coefficient of variation of less than 3 and 4%, respectively, and satisfactory Horwitz ratio values of <1.0. Excellent accuracy was proved by the high recovery values of 91.4–106.0% for campesterol, β-sitosterol, and stigmasterol. Δ⁵-Avenasterol, the most oxidation-susceptible sterol, showed a recovery of about 60%. The total phytosterol (sum of major phytosterols quantified) contents in the 19 samples varied from 38.8 mg/100 g (white quinoa seed) to 246.2 mg/100 g (sunflower seed). β-Sitosterol was the predominant phytosterol (54–86.0% of total) among all samples except fennel seed in which stigmasterol was predominant. Analytical quality control chart maintained during the study period showed that assays were performed under control. Method validation indicated that the analytical method can be applied for accurate determination of campesterol, β-sitosterol, and stigmasterol in selected food samples.     

Universal mitochondrial 16s rRNA biomarker for mini-barcode to identify fish species in Malaysian fish products

Mislabelling in fish products is a highly significant emerging issue in world fish trade in terms of health and economic concerns. DNA barcoding is an efficient sequencing-based tool for detecting fish species substitution but due to DNA degradation, it is in many cases difficult to amplify PCR products of the full-length barcode marker (~650 bp), especially in severely processed products. In the present study, a pair of universal primers targeting a 198 bp sequence of the mitochondrial 16s rRNA gene was designed for identification of fish species in the processed fish products commonly consumed in Malaysia. The specificity of the universal primers was tested by both in-silico studies using bioinformatics software and through cross-reaction assessment by practical PCR experiments against the DNA from 38 fish species and 22 other non-target species (animals and plants) and found to be specific for all the tested fish species. To eliminate the possibility of any false-negative detection, eukaryotic endogenous control was used during specificity evaluation. The developed primer set was validated with various heat-treated (boiled, autoclaved and microwaved) fish samples and was found to show high stability under all processing conditions. The newly developed marker successfully identified 92% of the tested commercial fish products with 96–100% sequence similarities. This study reveals a considerable degree of species mislabelling (20.8%); 5 out of 24 fish products were found to be mislabelled. The new marker developed in this work is a reliable tool to identify fish species even in highly processed products and might be useful in detecting fish species substitution thus protecting consumers’ health and economic interests.     

Quantitative duplex real-time polymerase chain reaction assay with TaqMan probe detects and quantifies Crocodylus porosus in food chain and traditional medicines

Consumption and exploitation of crocodiles have been rampant for their exotic, nutritive and medicinal attributes. These depredations are alarming and although they have continued to be monitored by wildlife and conservation agencies, unlawful trading of crocodiles shows an increasing trend worldwide. Recently, conventional polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) assays for crocodile have been documented but they are only suitable for identification and cannot quantify adulterations. We described here a quantitative duplex real-time PCR assay with probes to quantify contributions from Crocodylus porosus materials simultaneously. A very short amplicon size of 127bp was used because longer targets could have been broken down in samples, bringing considerable uncertainty in molecular analysis. We have validated a TaqMan probe-based duplex real-time PCR (qPCR) assay for the detection of 0.004 ng DNA in pure state and 0.1% target meat in model chicken meatball. False negative detection was eliminated through an endogenous control (141-bp site of eukaryotic 18S rRNA). Analysis of 12 model chicken meatballs adulterated with C. porosus reflected 96.3?120.2% target recovery at 0.1?10% adulterations. A validation test of 21 commercial food and traditional medicine (TM) crocodile-based products showed 100% effectiveness. Short amplicon sizes, alternative complementary target, exceptional stability and superior sensitivity suggested the assay could be used for the identification and quantitative determination of C. porosus in any food or TM samples even under degraded conditions.     

Effect of Medium-High Energy Emulsification Condition on Physicochemical Properties of β-Sitosterol Multiple Emulsion

Phytosterols are used to lower the blood cholesterol. β-Sitosterol is one of the most important phytosterols with very poor water solubility and bioaccessibility. The main goal of the current research was to investigate the effects of different emulsification variables (i.e. shear, time, pressure and cycle) on the physicochemical properties, release behaviour and encapsulation efficiency of β-sitosterol in water-in-oil-in water (W/O/W) emulsion. Initially, 19 β-sitosterol emulsions were prepared under different experimental conditions (shear 3000 and 6000 rpm; time 2.5 and 5 min; pressure 100, 200 and 300 bar; cycle 1–3). In this study, the β-sitosterol emulsion prepared at 6000 rpm, 5 min, 300 bar and 3 cycles had the smallest average droplet size (139 nm) among all prepared samples. The interaction between shear and time showed the most significant (P < 0.05) effect on the polydispersity index (PDI) and turbidity of the β-sitosterol emulsion. Increasing homogenization pressure and cycle led to improving emulsion stability and encapsulation efficiency. The β-sitosterol emulsion homogenised at 100 bar for 1 cycle had the highest encapsulation efficiency (81.7%) among all samples. The optimization study showed that the emulsification at 300 bar for 3 cycles resulted in the most desirable β-sitosterol emulsion.     

Biotransformation of phenolics (isoflavones,flavanols and phenolic acids) during the fermentation of cheonggukjang by Bacillus pumilus HY1

Changes in β-glycosidase, esterase activities, isoflavone, flavanols and phenolic acid during the fermentation of Korean whole soybean fermented food cheonggukjang by Bacillus pumilus HY1 were investigated. The levels of aglycones, flavanols and gallic acid increased, while the β-glucosidase activity, esterase activity, glycosides content (except for acetylglycosides) and flavanol gallates decreased. Total isoflavone content slightly decreased after 60 h of fermentation, while total flavanol and phenolic acid content increased. The highest levels of daidzein (aglycone type) and acetyldaidzin (glycoside type) were recorded after 48 h of fermentation. The levels of catechin, epicatechin and gallic acid also increased during fermentation. However, total contents of glycosides, malonylglycosides and flavanol gallates decreased by about 80%, 90% and 60% during 60 h of fermentation, respectively. In addition, total phenolic content increased markedly during fermentation, while levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity increased. Hence, it would be beneficial for the food industry if components of cheonggukjang could be separated and developed into functional products.