The anodic dehydrodimerization of dimethyl malonate

As a part of a study of the anodic dehydrodimerization of diethyl malonate on platinum in emulsions and micelles some experiments were run to obtain an insight on the mechanism of the reaction. It was determined that although some catalytic dehydrodimerization was obtained with pure diethyl malonate at elevated temperatures the yield from this type of reaction at room temperature was negligible. In pure acetonitrile, confirmation was obtained for the previously postulated mechanism which involved reaction at the anode of electrogenerated halogen with diethyl malonate anions which had been generated at the cathode.In aqueous emulsion and micelle systems it was found that yields of the dimer were obtained in the presence of bromide ions and a quaternary ammonium salt but were not obtained using other supporting anions including chloride. The best yields were obtained in emulsions composed of tetrabutylammonium bromide and water. It was concluded that the dimerization proceeded by a reaction between electrochemically generated bromine molecules and the diethyl malonate anion. No large amounts of bromine were found adjacent to the electrode if potassium bromide was the supporting electrolyte but bromine stayed in the neighborhood of the electrode if tetrabutylammonium ions were present.     

The firing squad synchronization problem for graphs

In this paper, we give a solution of the Firing Squad Synchronization Problem for graphs. The synchronization times of solutions which have been obtained are proportional to the number of nodes of a graph. The synchronization time of our solution is proportional to the radius r_G of a graph (G (3r_G + 1 or 3r_G time units, where r_G, is the longest distance between the general and any other node of G. This synchronization time is minimum for an infinite number of graphs.     

Optimization of the implosion phase on TC-I by light emission analysis

The best operation condition on the field-reversed theta-pinch TC-I at UNICAMP is studied by analysis of the helium-plasma light emission and electromagnetic signals observed during the preionization and implosion phase of FRC plasma. The TC-I device can be operated with a crowbar switch on the preionization and main capacitor banks, in order to fix the number of oscillations as well as the time interval between the end of the preionization and the main discharge phase. A detailed study of the plasma implosion has been carried out by changing the above parameters and also the working gas pressure by using a photodiode, a visible spectrometer, magnetic probes, a Faraday cup and a streak camera.     

A magnetic flowmeter with conducting pipe wall for expanded field of applications

The internal pipe wall of magnetic flowmeters should be non-conductive to prevent generated electromotive force from short-circuiting. Usually the inside of metallic pipe is lined with insulating material. The lining limits applicable temperature range of measured fluid and also its reliability. A new structure is proposed, in which the insulating liner is eliminated. A potential distribution is formed on the pipe wall by applying voltage proportional to fluid flowrate. The potential distribution is kept almost identical to the flow-induced potential in the fluid so that no current flows across the boundary between fluid and wall. Therefore the output signal is exactly the same as that of conventional magnetic flowmeters.     

Development of the compact English LVCSR acoustic model for embedded entertainment robot applications

In this paper we discuss two techniques to reduce the size of the acoustic model while maintaining or improving the accuracy of the recognition engine. The first technique, demiphone modeling, tries to reduce the redundancy existing in a context dependent state-clustered Hidden Markov Model (HMM). Three-state demiphones optimally designed from the triphone decision tree are introduced to drastically reduce the phone space of the acoustic model and to improve system accuracy. The second redundancy elimination technique is a more classical approach based on parameter tying. Similar vectors of variances in each HMM cluster are tied together to reduce the number of parameters. The closeness between the vectors of variances is measured using a Vector Quantizer (VQ) to maintain the information provided by the variances parameters. The paper also reports speech recognition improvements using assignment of variable number Gaussians per cluster and gender-based HMMs. The main motivation behind these techniques is to improve the acoustic model and at the same time lower its memory usage. These techniques may help in reducing memory and improving accuracy of an embedded Large Vocabulary Continuous Speech Recognition (LVCSR) application.     

Preparation and magnetic properties of electrospun CuO/NiO bimetallic nanofibers via sol–gel electrospinning

We report the fabrication and magnetic properties of the CuO/NiO bimetallic composite nanofibers prepared by sol–gel electrospinning and followed by calcination. The added precursors (copper nitrate trihydrate (CuNT) and nickel chloride hexahydrate (NiCH)) significantly influenced the fiber formation and its morphologies during electrospinning. The magnetic properties were investigated by Vibrating Sample Magnetometer and Electron Spin Resonance (ESR) curves. After calcination for the production of the metallic nanofibers, the fiber morphologies were dramatically changed depending on the added amounts of precursors ranging from 2.5 to 7.5 wt%. From the magnetic hysteresis loop (M-H curve) and ESR analysis of the calcined electrospun CuO/NiO bimetallic nanofibers, it was found that the magnetization of the calcined electrospun CuO/NiO bimetallic nanofibers with various weight ratio of CuNT:NiCH = 9:1, 1:1, and 1:9 at an applied magnetic field of 10 kOe was 0.480, 0.402, and 0.337 emu/g, respectively, indicating that the calcined electrospun CuO/NiO bimetallic nanofibers have magnetic properties.     

Novel chelate-setting calcium-phosphate cements fabricated with wet-synthesized hydroxyapatite powder

The hydroxyapatite (HAp) powder preparation process was optimized to fabricate inositol phosphate-HAp (IP6-HAp) cement with enhanced mechanical properties. Starting HAp powders were synthesized via a wet chemical process. The effect of the powder preparation process on the morphology, crystallinity, median particle size, and specific surface area (SSA) of the cement powders was examined, together with the mechanical properties of the resulting cement specimens. The smallest crystallite and median particle sizes, and the highest SSA were obtained from ball-milling of as-synthesized HAp powder under wet conditions and then freeze-drying. IP6-HAp cement fabricated with this powder had a maximum compressive strength of 23.1 ± 2.1 MPa. In vivo histological studies using rabbit models revealed that the IP6-HAp cements were directly in contact with newly formed and host bones. Thus, the present chelate-setting HAp cement is promising for application as a novel paste-like artificial bone.     

Measurement of milk color and composition: effect of dietary intervention on Western Australian Holstein-Friesian cow's milk quality

ABSTRACT:  Milk fat whiteness is the key to the uniqueness of Western Australian milk. Following a controlled feeding regime, milk was collected fortnightly for 6 mo from 2 treatment groups: dryland and irrigation. The results showed that it was possible to produce high-quality milk with whiter fat by a controlled feeding regime and diet while maintaining the health of Holstein-Friesian cows. The reflectance method using infinite optical thickness showed milk fat color differences due to feed could be measured. After 8 wk of the study, milk fat from the dryland treatment was significantly whiter ( P < 0.05) than the irrigation treatment with area under curve total reflectance of 902.8 and 838.3, respectively. The official Japanese industry method, Agriculture and Livestock Industries Corp. (ALIC) butter tone, showed that from the 2nd to the 5th collections the color of milk fat from cows fed silage and grain (dryland treatment) was significantly whiter ( P < 0.01) with an average butter tone of 0.15 absorbance per gram compared to cows fed green pasture and grain (irrigation treatment) with a butter tone of 0.21 absorbance per gram. Protein and riboflavin levels also affect the whiteness of milk. The study followed the main feeding protocol of dryland dairies and suggests the majority of milk from Western Australia would receive a grade 1 classification, as dryland dairies dominate supply.     

Synergistic or antagonistic modulation of oviposition response of two swallowtail butterflies, Papilio maackii and P. protenor, to Phellodendron amurense by its constitutive prenylated flavonoid, phellamurin

Papilio maackii females prefer a rutaceous plant, Phellodendron amurense, for oviposition, whereas another semi-sympatric Rutaceae feeder, Papilio protenor, never exploits this plant as a host in nature. However, the larvae of both species perform well on this plant in the laboratory. Phellamurin, a flavonoid present in the organic fraction from P. amurense inhibits egg laying by P. protenor. We examined whether phellamurin is involved in the differential acceptance of P. amurense by the two butterflies. The ovipositing females of P. maackii readily accepted P. amurense and a methanolic extract of the foliage, while P. protenor rejected them entirely. However, the aqueous fraction derived from the extract elicited significant oviposition responses of similar levels from the two species. Phellamurin did not induce oviposition behavior in P. protenor females. In contrast, P. maackii was stimulated to oviposit by phellamurin at concentrations exceeding 0.2%. The response was dose-dependent and reached ca. 70% at 2% phellamurin, which is approximately equivalent to its natural abundance in young leaves of P. amurense. Since the aqueous fraction was very stimulatory to both species, the combined effect of phellamurin and the aqueous fraction on oviposition was tested. The addition of phellamurin to the aqueous fraction enhanced the ovipositional activity of P. maackii, but dramatically suppressed the oviposition response of P. protenor even at 0.1% concentration. These results, taken together with those obtained from electrophysiological recordings with foretarsal chemosensilla, indicate that phellamurin acts as an oviposition stimulant for P. maackii, and as a potent deterrent for P. protenor. The results suggest that host range expansion or host shifts may be made by ovipositing females that overcome phytochemical barriers.     

Electrically-switchable, permselective membranes prepared from nano-structured N-doped DLC

In this study, we report a fabrication of a conductive DLC through-hole membrane with highly ordered nanopore arrays by template synthesis using an anodic porous alumina and effects of intrinsic properties of DLC (a wide working potential range and low ion adsorption) on ion permselectivity when the membrane is applied to separate ions.We have successfully fabricated the conductive DLC membranes that have pore diameters ranging from 14 nm to 105 nm and show electrically tunable charge selectivity. With these membranes, fluxes of cations across the membrane can be reduced by applying positive potentials and can be increased by applying negative potentials. In the case of anions, a selectivity pattern opposite to cations was observed. Inside pore surfaces of the conductive DLC membrane could have excess charge by potentiostatically charging. This excess charge regulates ion transport across the membranes. The membranes reject ions of the same sign as excess charge and transport ions of the opposite sign. The permselectivity of the membrane can be reversibly switched from cation-permselective to anion-permselective by changing potentials applied to the membrane (because the signs of excess charge can be controllable by applied potentials).DLC membrane exhibited ion permselectivity even in an electrolyte solution including ions strongly adsorb to electrode surfaces such as Na₂SO₄ and HCl solutions. By using DLC membrane, ion permselectivity can be controlled in real samples commonly including adsorbing ions (that cannot be controlled with Au nanotubule membrane due to a specific adsorption to electrode surfaces).We could also demonstrate the permselectivity of target ions by controlling the potential applied to the membrane even in the mixed solution, which contains both cations and anions and is close to actual samples including ions aimed to be separated.