Distribution of electric field for carbon nanotube assembly: Simulation (I)

The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area called the stable region or the quasi-stable region for an instant where the change of electric field is minimized. Since the conical electrode has the very narrow sized quasi-stable region, few CNTs can be attached. The rectangular electrodes have a wide stable region, so lots of CNTs can be attached. The results indicate that the round electrode which has a proper sized quasi-stable region is more effective for aligning and attaching a single CNT than the conical or rectangular shaped electrodes.     

Cr/nanodiamond composite plating with cobalt cation additive

The effect of cationic additive on Cr/nanodiamond plating was studied. Chromium plating was performed in Sargent bath. Morphology of deposit was observed by scanning electron microscope(SEM); microhardness by hardness tester; wear rate by tribometer; amount of diamond in deposit by combustion method and passivity by potentiodynamic scan. Experimental results show that in the presence of cobalt cation, the amount of nanodiamond particle in the deposit is increased. With increasing diamond particle amount, the metallurgical, mechanical and electrochemical properties of Cr/nanodiamond deposit are improved. However, this improvement seems to be constrained. In the presence of 10 g/L of nanodiamond powder and 2.5 g/L of cobalt cation in the bath, the amount of diamond particle in deposit is increased by 4 times; and wear rate of Cr-Co/nanodiamond deposit is decreased by 2–3 times as compared with pure Cr/deposit. The passive current of Cr-Co/nanodiamond composite deposit is decreased from 18 to 8 μA. The morphology of Cr/nanodiamond is smooth remarkably in the presence of cobalt cation.     

APPLE POSTHARVEST PRESERVATION IS LINKED TO PHENOLIC CONTENT AND SUPEROXIDE DISMUTASE ACTIVITY

The postharvest preservation of apples indicated that well-preserved varieties of apples had increased superoxide dismutase (SOD) activity initially, and the activity declined during later storage as apples deteriorated. The increased SOD activity linked to better preservation correlated with higher phenolic content and free-radical scavenging-linked antioxidant activity. Well-preserved varieties were able to maintain a more stable pentose phosphate pathway (measured by the activity of glucose-6-phosphate dehydrogenase) throughout the storage period. Proline content increased with proline dehydrogenase (PDH) activity in the initial storage period, indicating proline catabolism supporting potential adenosine 5'-triphosphate (ATP) synthesis. During later storage, succinate dehydrogenase activity increased, while PDH activity declined indicating a shift to tricarboxylic acid cycle and likely nicotinamide adenine dinucleotide hydrogen (NADH) generation for ATP synthesis. This shift, coupled with the declining SOD activity, coincides with rapid deterioration. The guaiacol peroxidase activity generally declined in late stages, indicating postharvest deterioration.

PRACTICAL APPLICATIONS

Understanding the phenolic-linked antioxidant response during postharvest preservation of apples has implications for understanding critical control points for preservation and determination of better biochemical markers associated with preservation and long-term storage. These insights would also help elucidate markers such as high phenolic content and antioxidant enzyme response pathways that would allow for selection and breeding of varieties that would preserve better. Higher phenolic content not only improves the postharvest storage of apples but have also shown human health benefits.     

Aqueous Extraction and Membrane Techniques Improve Coconut Protein Concentrate Functionality

Functional properties of coconut protein concentrates (CPC) from fresh coconut meat and commercial desiccated coconut meat were assessed and compared with other protein sources. Coconut proteins were extracted from undefatted meats at pH 7 in 0.5M NaCl solution. Protein recovery in the ultrafiltration retentates was about 40% (as % nitrogen) in the starting meats. Water absorption capacities of CPC products were lower than those of soy protein concentrates (SPC) and Na-caseinate, but there was no difference in oil absorption values among CPC, SPC and Na-caseinate. CPC products were more soluble than SPC, but less soluble than Na-caseinate at pH 8 and 10. Emulsifying properties of CPC were superior to those of caseinate and SPC. Total essential amino acids contents of CPC products were lower than caseinate, but similar to SPC.     

Flux Optimization During Tapping in BOF Process

An integrated Plate Mill has started it’s operation on July 7, 2010 in Gwangyang Steelworks, POSCO. The production capability is about 2.5 million tons per year and the main stream consists of Blast Furnace, Hot metal pretreatment (KR), Converter, Bubbling Station, RH/VTD and Continuous Casting. Particularly, it is possible to control sulfur concentration at excellent level in BOF without any further treatment in LF or VTD, which is attained by unique KR process and scrap usage strategy in BOF. In this paper, desulfurization efficiency and steel cleanliness was introduced by optimizing flux amount during tapping in BOF process. In addition, the effect of the flux addition on the refractory of ladle was investigated based on EPMA analyses with the viewpoint of phase diagram. The cleanliness of each sample was examined using optical emission spectrometry and oxygen nitrogen determinator.     

PWM buck-boost ac choppers for safe commutation

Novel pulse-width modulated (PWM) buck-boost ac choppers solving the commutation problem are proposed for single-phase and three-phase systems. The power circuits of the single-phase and three-phase buck-boost ac choppers use only two and three standard switch modules, respectively, and regenerative dc snubbers are attached directly to standard switch modules to absorb energy stored in line stray inductance. The switching policy for solving the commutation problem is achieved. Compared with previous buck-boost ac choppers, the switching loss is reduced and RC snubbers causing power loss are eliminated. The equivalent circuits of the proposed ac choppers are obtained and the power factor is derived from the equivalent circuits. The proposed ac chopper has the following advantages; improved power factor, low harmonics, sinusoidal input current, fast dynamics, high efficiency, high reliability, and significant reduction of the filter size. Experimental results show that the proposed scheme gives good steady-state performances of the ac chopper and that they coincide with the theoretical results.     

GROWTH RESPONSE OF A SALMONELLA TYPHIMURIUM POULTRY ISOLATE TO PROPIONIC ACID UNDER AEROBIC AND ANAEROBIC CONDITIONS

Organic acids have long been used as additives in poultry feed to reduce microbial populations, including Salmonella spp. Propionic acid addition to poultry feed has a potential role in reducing Salmonella spp. in the chicken intestine. In this study , in vitro growth response of S. typhimurium isolated from poultry to propionic acid under aerobic and anaerobic conditions was determined. When grown in tryptic soy broth (TSB) containing buffered propionic acid (BPA), the growth rate of S. typhimurium gradually decreased as the level of BPA increased and broth pH decreased. No growth was detected with BPA concentrations greater than 3% (volume/volume) of the broth. When the growth rates of S. typhimurium in aerobic and anaerobic TSB were compared at two pH levels (pH 5.0 and 7.0), the growth inhibition of S. typhimurium by propionic acid was markedly suppressed by anaerobiosis at both pHs, as indicated by significantly (p<0.05) higher half-inhibition constants (K°). Also, the growth rates of S. typhimurium in the presence of propionic acid were dramatically reduced by the decrease in pH from 7.0 to 5.0. The results of this study indicated that the growth inhibitory effect of propionic acid against S. typhimurium strains was enhanced by pH decrease and suppressed by anaerobiosis, suggesting that the growth response of S. typhimurium to propionic acid in the chicken intestine might be affected by the environmental conditions such as pH and anaerobiosis.     

Assessing Level of Ubiquitous Computing Services for Ubiquitous Business Design

We are entering into a new era of enterprise computing that is characterized by an emphasis on broadband convergence, knowledge sharing, and calm services. Some people refer to this as the "ubiquitous network" business model because its focus is on a high degree of connectivity between a company and its customers, suppliers, and channel partners. Moreover, immediate access to ideas, goods, and services will be of greater value than the traditional model of permanent and ponderous possession. This paper illustrates how ubiquitous computing technology can be combined with legacy computer-based information systems, along with thoughts on relevant issues of ubiquitous commerce. We also propose a model for how to assess levels of ubiquitous computing services.