Alumina supported copper nanoparticles for aziridination and cyclopropanation reactions

Alumina supported copper (Cu–Al₂O₃) nanoparticles were prepared and applied for the aziridination of olefins employing [N-(p-tolylsulfonyl)imino]phenyliodinane (PhI = NTs) as nitrene source to afford the corresponding 3-membered cyclic compounds in moderate to excellent yields. Cyclopropanation of several olefins was also carried out by using Cu–Al₂O₃ nanoparticles and ethyl diazoacetate as a carbene source. The catalyst was recovered by simple centrifugation and reused for four cycles.     

Unified analysis of switched diversity systems in independent andcorrelated fading channels

The moment generating function (MGF) of the signal power at the output of dual-branch switch-and-stay selection diversity (SSD) combiners is derived. The first-order derivative of the MGF with respect to the switching threshold is also derived. These expressions are obtained for the general case of correlated fading and nonidentical diversity branches, and hold for any common fading distributions (e.g., Rayleigh, Nakagami-m, Rician, Nakagami-q). The MGF yields the performance (bit or symbol error probability) of a broad class of coherent, differentially coherent and noncoherent digital modulation formats with SSD reception. The optimum switching threshold (in a minimum error rate sense) is obtained by solving a nonlinear equation which is formed by using the first-order derivative of the MGF. This nonlinear equation can be simplified for several special cases. For independent and identically distributed diversity branches, the optimal switching threshold in closed form is derived for three generic forms of the conditional error probability. For correlated Rayleigh or Nakagami-m fading with identical branches, the optimal switching threshold in closed form is derived for the noncoherent binary modulation formats. We show previously published results as special cases of our unified expression. Selected numerical examples are presented and discussed     

Correlation of the hot-hardness with the tensile strength of 304 stainless steel to temperatures of 1200°C

It is shown that the ultimate tensile strength, σ, of 304 stainless steel can be correlated with hot-hardness measurements at temperatures up to 1200°C using the expression σ = (H/3.0)(n/0.2n) ⁿ whereH is the diamond pyramid hardness number andn is the strain hardening coefficient. The strain hardening coefficient was obtained from a Meyer’s hardness coefficient at the room temperature test condition and for test temperatures up to about 0.5T _m , from the empirical relationshipn =k/λ. Herek is a constant equal to approximately 0.2 microns and λ is the subgrain dimension of the deformed specimen as obtained by transmission electron microscopy. Formerly with General Electric Company, Cincinnati, Ohio     

Effect of air leak on long term performance of air heater

In this paper, the effect of an air leak on the air heater performance is investigated. “Air leaking in” and “air leaking out” systems are examined. The effect of various parameters like leakage rate, mass flow rate, solar insolation, plate length and ambient temperature has been studied. The possibility that air leakage can take place from any where along the length of the collector has been incorporated in the model. It is found that, for “air leaking in” systems, efficiency goes up, while for “air leaking out” systems, efficiency decreases from the no-leak situation, and it depends on the position of the leak.     

Polynomials for guided scrambling line codes

Guided scrambling (GS) is a line coding technique developed specifically for high bit rate fiber optic transmission systems. This paper continues the development of GS coding by introducing more scrambling polynomials that can be used with this technique. First, a method is presented for constructing polynomials which can be used with balanced encoding. Then it is shown that these polynomials can be used as bases for large families of polynomials, an expansion whose usefulness is demonstrated with the presentation of power spectra for several code configurations. These results indicate that polynomials can be selected from these families to exercise control over average as well as worst-case statistics of the encoded bit stream, a property not available with any other single efficient, balanced line coding technique developed to date. Criteria for polynomial selection are given, and polynomials are recommended for several GS code configurations     

Determination of moisture content of concrete by microwave-resonance method

The moisture content of concrete is one of its important properties. A new method of measuring the moisture content of concrete and other building materials is described. The method is based on the measurement of the dielectric constant at microwave frequencies. Studies on concrete have shown that a linear relation exists between the evaporable water content of concrete and the instrument reading. The main advantages of this method are i) it is nondestructive, ii) rapid response of the instrument, iii) humidity gradients in the specimen can be studied iv) measurements are independent of the dielectric losses and the conductivity of the material, v) sharp resonance peak of the microwaves allows very accurate measurements.     

Second order elastic effects in an infinite,isotropic compressible medium with an elliptic hole subjected to a uniform tangential force at the boundary

Summary Second order elastic effects with respect to different materials are expected to give results which conform better to the observed results than those obtained in infinitesimal elasticity. The theory was developed byAdkins, Green, andShield [1], and subsequently applied to various simple problems by various authors [2], [3].Bhargava andPande [4], [5] after modifying the technique suggested byAdkins et al. have solved more general problems.In the present paper the complete elastic field has been determined for the case of an isotropic, infinite, compressible medium which has an elliptic hole whose boundary is acted upon by a uniform tangential force. The results differ significantly from those of the infinitesimal case. Some idea with respect to the distribution of the hoop stresses on the boundary can be obtained from the table given in appendix B. Hoop stresses for the infinitesimal case and the case with second order effects for incompressible and compressible materials are given for different ellipses.

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Zusammenfassung Die Betrachtung elastischer Effekte zweiter Ordnung läßt bei verschiedenen Materialien bessere Übereinstimmung mit den beobachteten Resultaten erwarten, als dies in der infinitesimalen Elastizitätstheorie möglich ist. Die Theorie wurde vonAdkins, Green undShield [1] entwickelt und in der Folge von verschiedenen Autoren [2], [3] auf verschiedene einfache Probleme angewendet.Bhargava undPande [4], [5] haben nach Änderung der vonAdkins und seinen Mitarbeitern vorgeschlagenen Methode allgemeinere Probleme gelöst.In der vorliegenden Arbeit wird das elastische Feld für den Fall eines unbegrenzten, isotropen, kompressiblen Mediums mit elliptischen Loch, an dessen Rand eine tangentiale Gleichlast angreift, bestimmt. Die Ergebnisse unterscheiden sich deutlich von jenen der infinitesimalen Theorie. Eine gewisse Vorstellung von der Verteilung der Umfangsspannungen am Lochrand gibt die Tabelle im Anhang B. Die Umfangsspannungen werden für den infinitesimalen Fall und für den Fall der Berücksichtigung der Effekte zweiter Ordnung sowohl für inkompensibles als auch für kompressibles Material unter Annahme verschiedener Ellipsen angegeben.

     

Evaluation of seismic fragility of structures—a case study

The present paper attempts to evaluate the seismic fragility for a typical elevated water-retaining structure. The structure is analysed for two cases: (i) empty tank; and (ii) tank filled with water. The various parameters that could affect the seismic structural response include material strength of concrete and reinforcing steel, effective prestress available in the tank, ductility ratio and structural damping available within the structure, normalised ground motion response spectral shape, foundation and surrounding soil parameters and the total height of water available in the tank. Based on this case study, the seismic fragility of the structure is developed. The results are presented as families of conditional probability curves plotted against peak ground acceleration (PGA) at two critical locations. The procedure adopted, incorporates the various randomness and uncertainty associated with the parameters under consideration.     

Effect of 7-nitroindazole on tolerance to morphine, U-50,488H and [D-Pen2, D-Pen5] enkephalin in mice

The effects of 7-nitroindazole (7-NI), an inhibitor of the neuronal nitric oxide synthase (nNOS) which does not increase blood pressure, on tolerance to the antinociceptive activity of mu-(morphine), kappa-(U-50,488H) and delta-([D-Pen2, D-Pen5]enkephalin, DPDPE) opioid receptor agonists were determined in mice. Male Swiss-Webster mice were made tolerant by twice daily injections of morphine (20 mg/kg, s.c.), U-50,488H (25 mg/kg, i.p.) or DPDPE (20 micrograms/mouse, i.c.v.) for 4 days. When tested on day 5, tolerance to their antinociceptive activity was evidenced by decreased response in chronic drug treated mice in comparison to vehicle-injected mice. Concurrent administration of 7-NI (20, 40 or 80 mg/kg, i.p.) with DPDPE did not modify the development of tolerance to the antinociceptive action of DPDPE. However, 7-NI (40 or 80 mg/kg, i.p.) inhibited the development of tolerance to the antinociceptive activity of morphine and U-50,488H but the lower dose of 7-NI (20 mg/kg, i.p.) was not effective. Chronic administration of 7-NI by itself did not modify the acute response to morphine, U-50,488H or DPDPE. It is concluded that a specific inhibitor of nNOS can inhibit tolerance to the antinociceptive activity of mu- and kappa- but not of delta-opioid receptor agonists in mice.     

Flavin mononucleotide (FMN)-ethylenediaminetetraacetic acid (EDTA) photogalvanic cell

The photovoltages and photocurrent in a photogalvanic cell containing flavin mononucleotide (FMN) and a reducing agent, ethylenediaminetetraacetic acid (EDTA) have been determined and found to be appreciable. The efficiency of the cell has been estimated to be ～ 0-048 percent. The electrochemical behaviour of FMN in the presence of EDTA has been examined by cyclic voltametry.