Direct Nuclear Demagnetization of Two Dimensional Solid 3He Adsorbed on Graphite

Direct nuclear demagnetization has been made for two-dimensional solid ³He adsorbed on graphite. The lowest temperature is estimated to be about 10 µK from the observed magnetization of the paramagnetic solid ³He. The deviation from, ideal behavior is explained by a simple heat flow model.     

Adaptive fuzzy control for wind-diesel weak power systems

This work is concerned with the development of an adaptive fuzzy logic controller for a wind-diesel system composed of a stall regulated wind turbine with an induction generator connected to an AC busbar in parallel with a diesel generator set having a synchronous generator. In this work we propose to use an adaptive network based inference system (ANFIS) in order to generate fuzzy membership functions and control rules for the controller. A feedback linearized proportional integral controller is used to provide the required expert knowledge. A controller design process is identified; it consists of generating input-output data pairs to identify the control variables range and initial fuzzy memberships, and then to tune or adapt them using an ANFIS network structure. The controller inputs are the frequency error and its integral for the governor part of the controller, and the voltage and frequency errors for the automatic voltage regulator. These are readily measurable quantities leading to a simple controller which can be easily implemented     

Cellular changes of rat embryonic fibroblasts by an actin-polymerization inhibitor, bistheonellide A, from a marine sponge

Bistheonellide A, an inhibitor of actin polymerization from the marine sponge Theonella sp., was introduced at a concentration of 100 nM into rat fibroblast of 2.4 x 10(4) cells/ml. Within 1 h, it disrupted stress fibers, accompanied by a marked change of the cell morphology, resulting in the formation of processes from the cell surface. Further incubation for 24 h in the presence of 100 nM bistheonellide A led to binucleation in most cells and subsequent inhibition of cell cycle progression. When bistheonellide A was withdrawn from the culture medium, binuclear cells began to grow again within 20 h and reverted to mononuclear morphology. Flow cytometric analysis fluorescence-activated cell sorting showed that 2C diploid DNA content in G1 phase was changed into 4C content of tetraploid for the bistheonellide A treated-cells in G1 phase and into 8C content during G2 and M phase. Therefore, we suggested that the bistheonellide A treatment inhibited cytokinesis, but not mitosis in M phase, and that treated cells were arrested at the early G1 phase. These effects of bistheonellide A on the cell cycle progression of 3Y1 fibroblast were also observed more prominently in cells synchronized in S phase with hydroxyurea. Cells in G0 phase were then activated by the addition of fetal calf serum in the presence of 100 nM bistheonellide A. Cell cycle progression of the bistheonellide A-treated cells was obviously slowed down or completely inhibited during G1 phase. These results reveal that actin filaments are not only essential to cytokinesis but also for promoting the progression of cell cycle G1 to S phase.     

Hyperfine Induced Magnetic Ordering in a S=1/2 Quantum Magnets on Kagomé Lattice

Susceptibility and specific heat measurements have been carried out down to 23 mK on polycrystalline [Cu₃(titmb)₂(OCOCH₃)₆]?H₂O {titmb = 1,3,5-tris(imidazol-1-ylmethyl)-2,4,6 trimethylbenzene} with S=1/2 antiferromagnet on Kagomé lattice. The results show an unexpected ferromagnetic long range ordering at 56 mK. The entropy change from 10 K to 23 mK is much larger than the entropy corresponding to electron spin S=1/2 of Cu²⁺. The large excess entropy reduction strongly suggests a novel magnetic ordering of the coupled Cu electron and nuclear spin (I=3/2) system. We propose that a frustrated ground state changes to the complex ferromagnetic ground state with help of the enhanced indirect nuclear spin interaction through the hyperfine interaction.     

A new facile synthesis of ultra fine magnesium oxide nanowires and optical properties

One-dimensional metal oxides nanowires like magnesium oxide (MgO) play an important role in several nanotechnological applications. MgO nanowires were synthesized for the first time via hydrothermal route using magnesium acetate and urea at 180?°C for 2?h. The synthesized MgO nanowires were characterized by means of X-ray diffraction (XRD), Fourier transformer Infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), transmission scanning electron microscopy (TEM) and thermal gravimetric analysis (TGA). The obtained results indicated that the MgO nanowires show a predominant well- crystalline cubic face-centered with an average diameter of 10?nm and an average length of 40???m. The optical band gap energy of the sample was found to be 3.45?eV. The sample indicates a broadband PL emission in UV region and exhibits a good photoluminescence behavior for photonic devices applications. It is evaluated that this novel synthetic method is very useful and serves as a facile, direct preparation mild chemical method giving mass production of one dimensional MgO nanowires.     

Evaluation of material constants in NdCa4O(BO3)3 piezoelectric single crystal

A neodymium calcium oxoborate NdCa₄O(BO₃)₃ piezoelectric single crystal that belongs to the monoclinic system with point group m was grown by the Czochralski technique. A practical evaluation method was developed to determine the 27 independent material constants for acoustic wave device applications. A longitudinal effect face–shear vibration was analyzed and used in the resonance–antiresonance measurement. This method avoided measuring d ₁₁ and d ₃₃ directly by use of X-bar and Z-bar, in which leak of electric field would cause large errors because of the very small dielectric constants. At room temperature, dielectric constants were ${{\varepsilon _{11}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{11}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-0em} {\varepsilon _0 }} = 9.9$ , ${{\varepsilon _{22}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{22}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-0em} {\varepsilon _0 }} = 15$ , ${{\varepsilon _{33}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{33}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-0em} {\varepsilon _0 }} = 10$ and ${{\varepsilon _{13}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{13}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-0em} {\varepsilon _0 }} = - 0.8$ , respectively. All the independent dielectric and elastic constants were determined in this work. The simulation of surface acoustic wave velocity showed a good agreement with the measured value.     

Current and Future Development in Lung Cancer Diagnosis

Lung cancer is the leading cause of cancer-related deaths in North America and other developed countries. One of the reasons lung cancer is at the top of the list is that it is often not diagnosed until the cancer is at an advanced stage. Thus, the earliest diagnosis of lung cancer is crucial, especially in screening high-risk populations, such as smokers, exposure to fumes, oil fields, toxic occupational places, etc. Based on the current knowledge, it looks that there is an urgent need to identify novel biomarkers. The current diagnosis of lung cancer includes different types of imaging complemented with pathological assessment of biopsies, but these techniques can still not detect early lung cancer developments. In this review, we described the advantages and disadvantages of current methods used in diagnosing lung cancer, and we provide an analysis of the potential use of body fluids as carriers of biomarkers as predictors of cancer development and progression.     

Capacitor placement for switching noise reduction using genetic algorithms and distributed computing

This work investigates capacitor placement on a printed circuit board (PCB) to reduce the effect of simultaneous switching noise as a genetic algorithm (GA) search problem. The solution process makes use of distributed computing resources available on a local area network in order to solve larger problems more efficiently. The objective is to determine the number of added capacitors with minimum cost, and their position on the PCB, while keeping the maximum voltage deviation within some specified noise margin. The presence of capacitors at the selected positions is represented by a stream of zeros and ones, which is interpreted as a genotype. At each generation, the GA assesses the fitness function of a population of genotypes using linear transient circuit analysis, which involves a single matrix inversion, by determining the maximum voltage dip given the capacitor locations. For large systems, the fitness calculations are divided among several processors according to a simple distributed computing algorithm.     

Probabilistic model of a two-site wind energy conversion system

A general probabilistic model of a two-site wind-energy conversion system (WECS) is described in this paper. The wind speeds at the two sites are not assumed to be independent, which prevents the convolution theorem from being directly applicable. Instead, a model based on the conditional probability theorem and mutually exclusive events is presented. The model supports the assessment of the energy resource available to supply a given load represented by its load duration curve, taking into consideration wind-turbine failure modes and the intermittent nature of the wind resource. The model is based on a capacity-probability table constructed using fundamental probability theorems on conditional and mutually exclusive events. The table is then combined with a load model in order to assess its performance and determine the expected energy not supplied (EENS) of the system. A planning study is then reported on a realistic system to illustrate how the most efficient wind turbines can be selected to support an existing thermal system using a procedure based on a minimization of the incremental marginal cost of operation.