Numerical study on flash‐boiling spray of multicomponent fuel

Flash‐boiling occurs when a fuel is injected into a combustion chamber where the ambient pressure is lower than the saturation pressure of the fuel. It has been known that flashing is a favorable mechanism for atomizing liquid fuels. On the other hand, alternative fuels, such as gaseous fuels and oxygenated fuels, are used to achieve low exhaust emissions in recent years. In general, most of these alternative fuels have high volatility and flash‐boiling takes place easily in the fuel spray when injected into the combustion chamber of an internal combustion engine under high pressure. In addition the multicomponent mixture of high‐ and low‐volatility fuels has been proposed in the previous study in order to control the spray and combustion processes in an internal combustion engine. It was found that the multicomponent fuel produces flash‐boiling with an increase in the initial fuel temperature. Therefore, it is important to investigate these flash‐boiling processes in fuel spray. In the present study, the submodels of a flash‐boiling spray are constructed. These submodels consider the bubble nucleation, growth, and disruption in the nozzle orifice and injected fuel droplets. The model is implemented in KIVA3V and the spray characteristics of multicomponent fuel with and without flashing are numerically investigated. In addition, these numerical results are compared with experimental data obtained in the previous study using a constant volume vessel. The flashing spray characteristics from numerical simulation qualitatively show good agreement with the experimental results. In particular, it is confirmed from both the numerical and experimental data that flash‐boiling effectively accelerates the atomization and vaporization of fuel droplets. This means that a lean homogeneous mixture can be quickly formed using flash‐boiling in the combustion chamber. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(5): 369–385, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20117     

An N-Gram and STF-IDF model for masquerade detection in a UNIX environment

A masquerader is someone who impersonates another user and operates a computer system with privileged access. Computer security problems caused by masqueraders are serious. Although anomaly detection is considered to be the best way to detect masqueraders, due to the low probability of detection and high error rate, this method is still in the research phase. Thus far, a number of methods, such as the Support Vector Machine (SVM), the Hidden Markov Model (HMM), and the Na?ve Bayes (N. Bayes) classifier technique, have been investigated in order to further improve accuracy of detection. In the present paper, a method of integrating Data Mining and Natural Language Processing, namely, the N-Gram_Square root Term Frequency-Inverse Document Frequency (N-Gram_STF-IDF), is proposed. Using the proposed method, sequences to be detected are segmented via N-Gram characteristics, and non-normal users are then detected using a STF-IDF classifier. We perform an experiment using Schonlau and Greenberg data sets and the proposed method and compare the obtained results with results obtained using various other methods.     

用HOQ拓展概念的软件描述及其定量结构化方法

为了改善软件的质量和生产性,注目于与其密切相关的软件结构.首先,讨论了现有方法中软件结构分析和设计的问题;然后根据质量设计中的质量屋HOQ(house of quality)与产品设计中的工程图之间的相似性,将质量功能展开QFD(quality function deployment)中的质量屋HOQ概念扩展成一种软件描述工具,并引入H.A.西蒙的系统准分解可能性原理,提出了基于数量化理论3类QMT3(quantification method of type 3)的软件定量结构化方法,再通过与现有方法的比较分析,阐明了该方法的特点;最后,通过应用实例验证了该方法对软件结构分析和设计的有效性.因而为软件质量保证提供了有力的支持.     

High-Response Digital Speed-Control System for Induction Motors

High-speed response is obtained for a vector control system by using new methods of speed control compensation, even when the secondary flux is lowered as a noise reduction measure. Moreover, simple circuits are developed which generate primary current reference signals quickly.     

Nucleobase amino acids incorporated into the HIV-1 nucleocapsid protein increased the binding affinity and specificity for a hairpin RNA

L-alpha-amino acids with a nucleobase in the side chain (nucleobase amino acids; NBAs) were used to enhance the function of RNA-binding proteins that recognize structured RNA. These NBAs were utilized in the three-dimensional structure of the protein to enhance RNA binding affinity and specificity as a result of selective recognition of NBAs by RNA bases. NBA units were incorporated at various positions into the HIV-1 nucleocapsid protein NCp7 (residues 1-55), which contains two CCHC-type (Cys-X(2)-Cys-X(4)-His-X(4)-Cys-type; X=an amino acid residue) zinc knuckle domains. The binding ability was evaluated by using the stem-loop (SL)3 region of HIV-1 Psi-RNA. Visible light absorption measurements revealed that two zinc ions bound strongly and quantitatively to the NBA-NCp7 molecule and to the wild-type NCp7 protein. This result indicates that the incorporation of NBA units composed of L-alpha-amino acids did not influence the formation of the specific structure of NCp7. Binding analysis with fluorescein-labeled SL3 RNA revealed that incorporation of NBA units into the NCp7 protein at appropriate positions increased its RNA binding affinity and specificity. An NBA-NCp7 protein that possessed cytosine and guanine NBA units at positions 13 and 46, respectively, showed a binding affinity for SL3 RNA ninefold higher than that of wild-type NCp7 as a result of the specific and cooperative interaction of the NBA units with RNA bases. These results clearly demonstrate that inclusion of NBA units in the three-dimensional structure of an RNA-binding protein is a useful strategy for enhancing the function of the protein.     

Isolation and characterization of an alkaliphilic bacterium utilizing pyrene as a carbon source

Alkaliphilic Mycobacterium sp. strain MHP-1, which can grow on pyrene as a sole carbon and energy source, was isolated from a soil sample. At the optimum pH for growth (pH 9), about 50% of pyrene (final concentration at 0.1% [w/v]) was degraded during 7 d of incubation, and 4,5-phenanthrenedioic acid, 4-phenanthroic acid and phthalic acid were identified as metabolic intermediates. Strain MHP-1 was found to possess aromatic-ring dioxygenase genes, which are highly homologous to the known nidAB genes from pyrene-degrading mycobacteria.     

Reachability of the sliding mode control for multimachine power systems

This paper presents conditions of reachability of a switching plane for the sliding mode control of phase shifters in multimachine power systems. Sliding mode controllers are usually synthesized so as to satisfy only the existence condition of a sliding mode. However, there is the border of an asymptotically stable region and a system state cannot reach a switching plane unless a state at the beginning of control (initial state) exists in that region. Hence, reachability is defined as an asymptotic stability of the initial state. A sufficient condition to reach onto a switching plane is given by an energy‐type Lyapunov function. It is described by control parameters that are introduced to find required control gains rather than feedback gains themselves. This allows us to straightforwardly evaluate an asymptotic stability. A phase‐shift control system is numerically tested in a 2‐machine 1‐infinite‐bus power system. The simulation results show that the improved control system offers faster transient stability and achieves the reachability of a switching plane. © 2000 Scripta Technica, Electr Eng Jpn, 131(3): 43–50, 2000     

Evaluating the Effect of Lenvatinib on Sorafenib-Resistant Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is one of the major causes of cancer-related deaths worldwide. Sorafenib has been used as a first-line systemic treatment for over a decade. However, resistance to sorafenib limits patient response and presents a major hurdle during HCC treatment. Lenvatinib has been approved as a first-line systemic treatment for advanced HCC and is the first agent to achieve non-inferiority against sorafenib. Therefore, in the present study, we evaluated the inhibition efficacy of lenvatinib in sorafenib-resistant HCC cells. Only a few studies have been conducted on this topic. Two human HCC cell lines, Huh-7 and Hep-3B, were used to establish sorafenib resistance, and in vitro and in vivo studies were employed. Lenvatinib suppressed sorafenib-resistant HCC cell proliferation mainly by inducing G1 cell cycle arrest through ERK signaling. Hep-3B sorafenib-resistant cells showed partial cross-resistance to lenvatinib, possibly due to the contribution of poor autophagic responsiveness. Overall, the findings suggest that the underlying mechanism of lenvatinib in overcoming sorafenib resistance in HCC involves FGFR4-ERK signaling. Lenvatinib may be a suitable second-line therapy for unresectable HCC patients who have developed sorafenib resistance and express FGFR4.     

Pharmaceutical Evaluation of Multipurpose Excipients for Direct Compressed Tablet Manufacture: Comparisons of the Capabilities of Multipurpose Excipients with Those in General Use

Recently, a novel type of multipurpose excipient (MPE) with high binding characteristics and high fluidity has been developed. In this study, the capabilities of MPEs (Ludipress and Microcelac) were compared with those of excipients in general use. Also, the effects on powder and tableting characteristics of the physical properties and contents of active ingredients were examined in tablets prepared with these MPEs by the direct compression method. Multipurpose excipients mixed with adjuvants such as fillers, binders, lubricants, disintegrants, and the like show superior fluidity and compressibility. Tablets containing very small amounts of highly active ingredients with little dispersion were prepared. However, with increases in active ingredient content, each of the physical properties was affected strongly by the properties of the active ingredient. Tablets with appropriate hardness and disintegration characteristics could be prepared by mixing of different types of MPEs.     

Diffication of high affinity fatty acid receptors in rat myocardial sarcolemmal membranes

High affinity receptors for fatty acid were purified from rat cardiac sarcolemmal membrane using gel filtration, DEAE-cellulose chromatography and affinity chromatography. The purified protein was homogeneous on polyacrylamide gel electrophoresis with the molecular weight of 60 kDa. Binding studies revealed the presence of a single class of high affinity binding sites with an apparent dissociation constant of 1.0 μM and a maximal binding capacity of 12.1 pmol/μg protein.