Petroleum naphthenomono-and naphthenobiarenes

The hydrocarbon-group composition and distribution of naphthenoaromatic hydrocarbons of West Siberian oils were studied by the technique of mass spectrometry. Naphthenoaromatic hydrocarbons of the general formula C_nH_2n?z , where z is 8, 10, 12, 14, 16, or 18, containing from one to six saturated cycles are present in oils in significant concentrations. Naphthenomonoarenes with one saturated cycle dominate in all oils. An increase in the amount of compounds containing 3–6 saturated cycles in their molecule with the occurrence depth was noted. Naphthenobiarenes of the general formula C_nH_2n?z , where z is 14, 16, 18, 20, 22, or 24 containing from one to six saturated cycles are present in oils in concentrations from 20.0 to 54.0 wt % of the biaromatic fraction. Most oils are characterized by the prevalence of structures with one and two saturated cycles in their molecule. The dependence of the number of cycles in naphthenobiarenes on the nature of original organic matter (OM) was not traced. The lack of correlation between the number of cycles and the OM type is presumably due to the fact that, for the most part, fused polycyclic naphthenobiarenes reflect the degree of catagenetic alteration of organic matter.     

Piezoelectrically actuated four-bar mechanism with two flexible links for micromechanical flying insect thorax

In this paper, a piezoelectrically actuated four-bar mechanism with two flexible links is proposed to be used in a micromechanical flying insect robot wing thorax for stroke amplification. PZT-5H- and PZN-PT-based unimorph actuators are utilized at the input link of the four-bar for a compact and lightweight thorax transmission mechanism. The kinematics and dynamics of the proposed wing structure with two parallel four-bar mechanisms are analyzed, optimal four-bar link size selection method is introduced, and quasistatic forces generated at the wing are computed for evaluating the feasibility of the design. Using laser micromachining and folding techniques, prototype four-bar structures are constructed. In the experiments, for a 10/spl times/1/spl times/0.12 mm/sup 3/ PZT-5H actuator-based four-bar mechanism, the stroke amplification of around 20 - 25 is held, and an attached polyester wing is resonated at 29 Hz with around 90/spl deg/ flapping motion. These results match closely with the predicted theoretical values.     

Extractive Properties of Synergistic Mixtures of Dipicolinic Acid Diamides and Chlorinated Cobalt Dicarbollide

Extraction of Cs, Sr, Eu, U, Np, and Am with mixtures of dipicolinic acid diamides with chlorinated cobalt dicarbollide was studied. A synergistic effect was revealed.     

An Acoustic Converter Used to Measure Ionizing Radiation Energy Loss

A monitor is proposed based on ultrasonic production when ionizing radiation passes through a medium. The recording element is a 0.2 mm aluminum plate mounted in a ceramic acoustic converter AC in the form of a wedge of thickness 2 mm. The low plate thickness minimizes the beam parameter distortion, while special technology used in the AC provides high sensitivity. The device has been calibrated in the proton beam from the ITEP accelerator at 200 MeV with 2·10⁹–6·10¹⁰ particles in a pulse and a pulse length of 70 nsec.     

Multilayer power printed structures suitable for controlling EMI noises generated in power converters

Electromagnetic interference (EMI) noises generated in power converters are diffused on the surface of conductors. This means influences occur from radiated EMI noises emitted from power transmission lines as well as conducted EMI noises transmitted from them. EMI noises diffusing on the surface of conductors are generally difficult to control using conventional concentrated constant theory. Thus, a new approach based on distributed constant circuit theory is needed in order to control EMI noises. A power converter structure to control EMI noises using multilayer power printed circuit technology is studied in this paper. A structure which can control EMI noises should simultaneously satisfy two conditions, i.e., one to shut down and one to attenuate EMI noises. The structure satisfying these conditions is studied through simulations using the Transmission-Line Modeling Method. The simulations show that the diffusion of EMI noises is controlled by dividing the flow of currents produced by EMI noises into the horizontal and perpendicular directions. That is, the horizontal current flow is controlled inside using the differences in the resistance produced from differences between inner and outer diameter of power transmission lines and the perpendicular current flow can be controlled by properly designing the thickness of the dielectric layer sandwiched between P-and N-power transmission lines with the symmetrical structure. Moreover, it is confirmed by simulations and experiments that the attenuation of EMI noises is affected by the width of the power transmission lines. It is expected that the results obtained in this paper can provide important rules when designing power converters with EMI noise control functions which use the multilayer power printed circuit technology.     

An investigation of sugar extraction methods and the use of microwave power for date syrup processing: efficiency and color related considerations.

This study investigates the effect of extraction methods on the color of date syrup and the potential use of microwave power for syrup processing. Sugar solutions were extracted from dates by boiling, soaking and blending. Color and sugar content of the extracted solutions were measured, and the percentage of sugar extracted form the total fruit sugar determined. Boiling was found to be the most efficient method of extraction whereby 74% of total samples sugar was extracted. In contrast, only 54.2% of fruit sugar was extracted by blending and 42% by soaking. In addition, solutions extracted by soaking and blending had a foaming problem in the subsequent concentration process. The extraction method had no effect on the product final color. The extracted solution was concentrated using two heating methods: conventional and microwave heating at a 600 W capacity and a frequency of 2450 MHz applied at three power levels: 10, 7, and 6. In the heating process, 180 minutes were needed to achieve a 77% degrees Brix using convective heating, while it took 81, 138, and 166 minutes of microwave heating at power level 10, 7, and 6, respectively to achieve the same concentration. Water activity of the syrup was measured within a sugar content range of 50 to 80% degrees Brix and the sugar concentration at which the product is shelf stable was determined at 76%.     

Phosphorus‐containing polyaryloxydiphenylsilanes with high flame retardance arising from a phosphorus–silicon synergistic effect

Polyaryloxydiphenylsilanes were prepared from phosphorus‐containing diols and diphenydichlorolsilane through solution polymerization. With a stoichiometric imbalance in feed monomers, the resulting polymers exhibited moderate melting points and good processing properties. The polymers prepared showed initial decomposition temperatures above 340 °C, excellent thermal stability, high char yields at 850 °C and very high limited oxygen index values of 56–59. The polymers' char yields and their (P + Si) contents showed linear relationships. © 2003 Society of Chemical Industry     

Preschool Competency in Context: An Investigation of the Unique Contribution of Child Competencies to Early Academic Success.

The present concurrent study combined developmental and ecological considerations to examine the unique contribution of multiple preschool competencies to an indicator of early academic success. Participants included 195 Head Start children from 32 classrooms representative of a large, urban Head Start program. Dimensional (variable-centered) analyses revealed 3 distinct classroom competency dimensions (i.e., General Classroom Competencies, Specific Approaches to Learning, and Interpersonal Classroom Behavioral Problems). The first 2 of these dimensions were found to be uniquely associated with early academic success. Findings from typological (person-centered) analyses supported the dimensional findings. Typological analyses revealed 7 profiles of classroom competency distinguished by high scores on the dimensions of General Competencies and Approaches to Learning, and these profiles were found to relate differentially to the indicator of early academic success. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Techniques for microstructural characterization of powder-processed nickel-based superalloys

Methods are described for sample preparation of polycrystalline Ni-based superalloys in order to perform a detailed microstructural characterization. Specific techniques for the precise definition of the various phases present are outlined and these are shown to be useful for the measurement of size, volume fractions and distribution. A number of optical, scanning and transmission microscopy techniques are used to provide the necessary information.