A fast response thermocouple for internal combustion engine surface temperature measurements

A fast response thermocouple was developed for measuring surface temperatures of aluminum components in ICE combustion chambers. The key features of the design are the use of the aluminum substrate as one of the thermocouple metals and the use of a thick copper layer as the hot junction at the surface. The copper equalizes the hot junction temperature with the surrounding aluminum to correct for the differences in thermal properties between the two materials. FEA determined the optimum thickness of the copper layer to be between 100 and 125 μm. Under typical SI engine heat flux conditions, the thermocouple should be able to measure average surface temperatures within 0.19 °C and the magnitude of temperature swings within 6% of true values.Following the FEA, the optimized thermocouple was tested in a SI engine. Experimental results displayed the same trends as the FEA at measuring average temperatures and temperature swings, suggesting the thermocouple was performing as predicted.     

Vanadium–Schiff base complex-functionalized SBA-15 as a heterogeneous catalyst: synthesis,characterization and application in pharmaceutical sulfoxidation of sulfids

Research on Chemical Intermediates - VO2(picolinichydrazone) complex as a catalyst was stabilized on a SBA-15 mesoporous silica as a catalytic support by using (3-chloropropyl)triethoxysilane as a...     

Composition of the essential oil of <Emphasis Type="Italic">Stachys acerosa</Emphasis> growing in central Iran

The essential oil of aerial parts of Stachys acerosa, which belongs to the Lamiaceae family and grows in central Iran, was obtained by a hydrodistileation method and analyzed by GC and GC-MS apparatus. Fourteen compounds representing 98.8% of the oil were identified. Among them N-methylisatin (30%), α-pinene (25%), sabinene (12.3%), and 2-hydroxyacetophenone (11.2%) were the major constituents of the oil, which was obtained in 0.1% yield. Published in Khimiya Prirodnykh Soedinenii, No. 1, pp. 32–34, January–February, 2007.     

Cohomology theories based on Gorenstein injective modules

In this paper we study relative and Tate cohomology of modules of finite Gorenstein injective dimension. Using these cohomology theories, we present variations of Grothendieck local cohomology modules, namely Gorenstein and Tate local cohomology modules. By applying a sort of Avramov-Martsinkovsky exact sequence, we show that these two variations of local cohomology are tightly connected to the generalized local cohomology modules introduced by J. Herzog. We discuss some properties of these modules and give some results concerning their vanishing and non-vanishing.

     

A novel one-pot,four component synthesis of some densely functionalized pyrroles

A new one-pot four component procedure for synthesis of densely functionalized pyrroles using commercially available ninhydrin with phosphorane intermediates produced in the reaction between triphenylphosphine, ammonium thiocyanate (or ammonium acetate) and various dialkyl acetylenedicarboxylates was developed.     

Electrooxidation of iodide in the presence of 4-hydroxycoumarin: application to a simple coulometric titration of 4-hydroxycoumarin.

The electrochemical oxidation of iodide ion in the presence of 4-hydroxycoumarin (1) was studied using cyclic voltammetry and controlled-potential coulometry. The result indicates that the resulting iodine takes part in a halogenation reaction and reacts with 4-hydroxycoumarin (1). According to the obtained results, a new and simple coulometric titration method with potentiometric end-point detection for the determination of 4-hydroxycoumarin (1) is presented. In the presented method, 2-200 micromol of 4-hydroxycoumarin (1) was successfully determined.     

Development of a novel microfluidic immunoassay for the detection of Helicobacter pylori infection

The miniaturization of laboratory processes offers substantial advantages over traditional techniques in terms of cost, speed, and potential for multistage automation. To date, only a few studies have reported successful microfluidics-based immunoassays, most of which rely on fluorescence detection technologies. The goal of this study was to develop a poly(dimethylsiloxane) microfluidics-based immunoassay methodology and a versatile colorimetric quantification scheme for the detection of visual colour changes resulting from immune reactions in microchannels. The novel immunoassay technique was applied towards the detection of Helicobacter pylori infection using 20 human serum samples of known infection status, and results compared with conventional nitrocellulose membrane-based dot-ELISA. The microchannel immunoassay reliably detected H. pylori antigens in quantities on the order of 10 ng, which provides a sensitivity of detection comparable to conventional dot-blot assays. Sensitivity was 100%, specificity was 90%, positive predictive value 91%, and negative predictive value 100%, with an overall accuracy of 95%. The software developed generated results that were consistent with visual observations and by automatically taking into account background intensity changes, the software minimized subjectivity. Volumes of solutions used were 100-fold less compared with conventional immunoassays. Miniaturization of the ELISA using this technique provides a means for the accurate diagnosis of microbial infection while minimizing waste production.     

Hilbert transform of

There are two general ways to evaluate the Hilbert transform of a function of real variable . We can extend to a harmonic function in the upper half plane by the Poisson integral formula. Non-tangential limit of its harmonic conjugate exists almost everywhere and is defined to be the Hilbert transform of . There is also a singular integral formula for the Hilbert transform of . It is fairly difficult to directly evaluate the Hilbert transform of . In this paper we give an explicit formula for the Hilbert transform of , where is a function in the Cartwright class.

     

The effects of rate of expansion and injection of water droplets on the entropy generation of nucleating steam flow in a Laval nozzle

The entropy generation due to irreversible heat transfer between vapor and liquid phases in a nucleating steam flow in a Laval nozzle is studied. To calculate the entropy generation due to self-condensation in transonic steam flow, a thermodynamic model is presented. The calculations of nucleating steam flow and the predictions of entropy generation rely on one-dimensional two-phase model. This model shows that the most of the thermodynamic losses take place during the nucleation phenomena. The effect of rate of expansion on the exergy losses is considered by decreasing the divergent angle of nozzle. Also micro-sized pure water droplets is injected theoretically to supercooled steam right after the nozzle throat at the onset of divergent section and the effects of injected droplets on thermodynamic losses and nucleation phenomena are investigated. The results indicate that decreasing the divergent angle and also injection of droplets diminishes the pressure rise in transonic steam flow and decreases the thermal entropy generation due to nucleation.     

Novel ionic liquid supported on Fe3O4 nanoparticles as an efficient catalyst for the synthesis of new chromenes

An efficient procedure for the synthesis of new chromenes by the multicomponent reaction of aldehydes, 4‐hydroxycoumarin and 2‐hydroxynaphthalene‐1,4‐dione in the presence of an ionic liquid supported on Fe₃O₄ nanoparticles is described. The ionic liquid supported on Fe₃O₄ nanoparticles as a magnetic catalyst gives products in high yields. Significant features of this method are: short reaction times, excellent yields, green method and use of an effective catalyst that can be recovered and reused many times without loss of its catalytic activity.