Augmentation of boiling heat transfer from horizontal cylinder to liquid by movable particles

This paper presents a series of experimental results on a passive augmentation technique of boiling heat transfer by supplying solid particles in liquid. A cylindrical heater 0.88 mm in diameter is placed in saturated water, in which a lot of mobile particles exist, and the nucleate and film boiling heat transfer characteristics are measured. Particle materials used were alumina, glass, and porous alumina, and the diameter ranged from 0.3 mm to 2.5 mm. Particles are fluidized by the occurrence of boiling without any additive power, and the heat transfer is augmented. The maximum augmentation ratio obtained in this experiment reaches about ten times the heat transfer coefficient obtained in liquid alone. The augmentation ratio is mainly affected by the particle material, diameter, and the height of the particle bed set at no boiling condition. The augmentation mechanism is discussed on the basis of the experimental results. © 2001 Scripta Technica, Heat Trans Asian Res, 31(1): 28–41, 2002     

ASYMPTOTIC PROPERTIES OF THE SAMPLE AUTOCORRELATIONS AND PARTIAL AUTOCORRELATIONS OF A MULTIPLICATIVE ARIMA PROCESS

Abstract. We shall investigate the asymptotic behaviour of the sample autocorrelations and partial autocorrelations of a multiplicative ARIMA process and derive their limiting distributions. Some simulations are presented to illustrate the results obtained.     

Preparation and antibacterial activity of novel fluoroalkyl end-capped oligomers/silica nanocomposites-encapsulated low molecular biocides

Fluoroalkyl end-capped N-(1,1-dimethyl-3-oxobutyl)acrylamide oligomer [R_F-(DOBAA) _n -R_F] reacted with tetraethoxysilane (TEOS) and silica nanoparticles in the presence of low-molecular weight biocides such as hibitane, hinokitiol, and hinokioil under alkaline conditions to afford R_F-(DOBAA) _n -R_F/silica nanocomposites-encapsulated these biocides in excellent to moderate isolated yields. Fluoroalkyl end-capped N,N-dimethylacrylamide oligomer [R_F-(DMAA) _n -R_F] and acrylic acid oligomer [R_F-(ACA) _n -R_F]/silica nanocomposites-encapsulated hibitane were obtained under similar conditions. Dynamic light scattering measurements showed that the size of these fluorinated nanocomposites-encapsulated biocides thus obtained is nanometer size-controlled. Additionally, these fluorinated nanocomposites were shown to have a good dispersibility and stability in methanol and water. Of particular interest, these fluorinated nanocomposites-encapsulated biocides were found to have a good antibacterial activity against Staphylococcus aureus, and these nanocomposites were applied to the surface modification of traditional organic polymers such as poly(methyl methacrylate).     

Real-time measurement of pointing action by using DSP

This paper presents an approach of measuring in real-time the vector of finger that is pointing to an object. DSP is used in the operation processing unit in order to do the real-time processing. The steps include the extraction of flesh-colored regions from an image, the labeling of the flesh-colored regions, and the detection of two characteristic positions on the finger so that the direction that the finger is pointing at will be calculated. The entire process takes about 29 msec, which makes it possible to have the frame rate of 34 fps. With this frame rate, this measurement approach is considered real-time and promising to be merged into other application systems. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Nitric oxide synergistically enhances DNA strand breakage induced by polyhydroxyaromatic compounds, but inhibits that induced by the Fenton reaction

This paper deals with the muscle force of the cervical spine in patients with cervical syndrome compared to the muscle activity in non-patients. It has thus been observed that both the flexors' and the extensors' force of the cervical spine is much greater in non-patients (the flexors' P < 0.01 and the extensors' P < 0.01). The precise measurements having been carried out by a dynamometer. The groups being tested comprised 50 persons each, 25 men and 25 women. The average age of the patients group was 43.1 years, namely between 21 and 57 years, while that of the non-patients group was 42.3 years, between 24 and 56 years. As regards the professional engagement of both groups and, accordingly, the strain on the cervical spine and the corresponding musculature, they were approximately the same.     

A demonstrative study for the wind and solar hybrid power system

In March 1995, a small scale wind and solar hybrid power system was installed at Ashikaga Institute of Technology. Until now, the authors have acquired the data of the output of the hybrid power plant along with wind speed, wind direction, and the solar radiation, in order to demonstrate a complementary relationship between solar energy and wind energy.After nine months operation of the system, the authors confirmed that there exists a complementary relationship between solar energy and wind energy. We also found, however, that the power output by wind does not have much prospect compared to that by solar cell especially in summer season in Ashikaga area.     

Beam test of the CsI(Tl) calorimeter for the BELLE detector at the KEK-B factory

We studied the performance of a prototype electromagnetic calorimeter for the BELLE detector at the KEK proton synchrotron for an energy range of 0.25–3.5 GeV. The prototype consisted of an array of 6 × 5 CsI(Tl) crystals with 30 cm length (16.2 radiation lengths) and about 6 cm × 6 cm cross section. The scintillation light of each CsI(Tl) crystal was read out by two large-area PIN photodiodes and charge-sensitive preamplifiers attached at the rear face of the crystal. We measured the energy and position resolution for electrons and the e/π separation for two sets of matrix configurations: one corresponded to the center and the other to the edge of the barrel calorimeter. The overall performance measured by the test proves that the prototype calorimeter is satisfactory for the use in the BELLE detector.     

Forensic toxicological application of TOXI-LAB screening for biological specimens in autopsy cases and emergency cares

Using the TOXI-LAB drug detection system, emergency toxicological screening was performed in autopsy cases and emergency cares. In 280 autopsy cases (male 182 cases 65%, female 98 cases 35%), drug positive cases were 28 cases of male (15%) and 24 cases of female (24%). The age groups which showed higher rate of drug positive cases were 10s-40s in male (approximately 20%) and 20s in female (67%). In the 238 cases of emergency care (male 129 cases 54%, female 104 cases 44%, unknown 5 cases 2%), drugs were positive in 29 cases of male (22%) and 32 cases of female (30%). The age groups which showed relatively higher rate of drug positive cases were 40s in male (64%), 20s (71%) and 30s (89%) in female. Forty-four different kinds of drugs were detected in TOXI-LAB positive cases, in which the psychotropic drugs and the sedative-hypnotic drugs amounted to approximately 70%. Methamphetamine and amphetamine, which were the main abused drugs showing a socially important problem, were detected in total 15 cases. TOXI-LAB was based on thin-layer chromatography (TLC); however, from the extraction to development, coloration and detection have been accelerated (about 50 min) and simplified. In order to perform the forensic toxicological practice in Japan, it becomes more useful that TOXI-LAB is used in autopsy cases and emergency cares, if the drugs, which have caused poisoning cares in Japan, are added to TOXI-LAB. The present study describes the advantage and problem of TOXI-LAB drug detection system through demonstrating the practical cases of autopsy cases and emergency cares.     

Molecular neurogenetics of chemotaxis and thermotaxis in the nematode Caenorhabditis elegans

Chemotaxis and thermotaxis in Caenorhabditis elegans are based on the chemical senses (smell and taste) and the thermal sense, respectively, which are important for the life of the animal. Laser ablation experiments have allowed identification of sensory neurons and some interneurons required for these senses. Many mutants that exhibit various abnormalities have been isolated and analyzed. These studies have predicted novel signaling pathways whose components include a putative odorant specific transmembrane receptor (ODR-10) and a cyclic nucleotide-gated channel (TAX-4/TAX-2) functioning in taste and thermosensation as well as in smell. The emerging picture of the mechanisms of sensory transduction in C. elegans seems to be basically similar to what is known of visual and olfactory sensory transduction in vertebrates. Thus, molecular and cellular analyses of chemotaxis and thermotaxis in C. elegans have proved useful and will continue to provide significant implications for the molecular basis of sensory systems in higher animals.     

Facile optical resolution of amino acid esters via hydrolysis by an industrial enzyme in organic solvents

Racemic amino acid esters were optically resolved via hydrolysis in organic solvents by the catalysis of an industrial alkaline protease, “Alcalase”. The products which were composed mainly of L-amino acids were insoluble and easily separated by filtration. The activity of the enzyme and enantiomeric excess of the products were significantly dependent on the nature of solvent and the water content in the reaction media. Generally, high values of enantiomeric excess were obtained at low water contents. Many natural and unnatural amino acids were resolved by this method.