Effects of chemical reaction on free convection flow through a porous medium bounded by a vertical surface

The effect of a chemical reaction on a free convection flow through a porous medium bounded by a vertical infinite surface has been studied. Velocity, temperature, and concentration profiles have been obtained for different values of parameters like the Grashof number, Prandtl number, and the chemical reaction parameter in the presence of homogeneous chemical reaction of first order. It is observed that the velocity and concentration increase during a generative reaction and decrease in a destructive reaction. The same is true for the behavior of the fluid temperature. The presence of the porous media diminishes the temperature.     

Synthesis, Characterization, and Cytotoxicity Analysis of a Biodegradable Polyurethane

A polyester urethane was synthesized for use in a biodegradable scaffold. The polyurethane was synthesized in a two-step process: first, ester diol was synthesized from lactic acid and polyethylene glycol 400 (PEG 400), then it was polymerized with toluene diisocyanate using dibutyl tin dilaurate (DBTDL) as a catalyst to form a polyester urethane. Polyester urethane has tensile strength of 51-59 MPa and elongation at fracture of 369-439%. FTIR and XRD were used to confirm the formation and structure of the polymer. Hydrolytic degradation was studied in different alkali solutions and in saline water. In order to assess the cellular response of this material, cytotoxicity analysis was carried out against the cell line.     

Structural, dielectric and electrical properties of Pb(SnTi)O3 ferroelectric system

We have synthesized (PST) with x=0.45, 0.55, 0.65 ferroelectric ceramics by a solid-state reaction technique and performed preliminary X-ray diffraction (XRD) analysis and the temperature and frequency dependence dielectric measurements on them. The a.c. and d.c. conductivities have been investigated over a wide range of temperature and the activation energy have also been calculated. It is observed that: (i) the relative dielectric permittivity () and loss tangent (tan ) are dependent on frequency, (ii) the temperature of dielectric permittivity maximum shifts toward lower temperature side, (iii) permittivity maximum decreases with the increase of Sn content in the (PST) compounds and (iv) no frequency dispersion of the dielectric permittivity reveals the no-relaxor behavior of the materials.     

Lattice orientation and crack size effect on the mechanical properties of Graphene

The effect of lattice orientation and crack length on the mechanical properties of Graphene are studied based on molecular dynamics simulations. Bond breaking and crack initiation in an initial edge crack model with 13 different crack lengths, in 10 different lattice orientations of Graphene are examined. In all the lattice orientations, three recurrent fracture patterns are reported. The influence of the lattice orientation and crack length on yield stress and yield strain of Graphene is also investigated. The arm-chair fracture pattern is observed to possess the lowest yield properties. A sudden decrease in yield stress and yield strain can be noticed for crack sizes <10 nm. However, for larger crack sizes, a linear decrease in yield stress is observed, whereas a constant yield strain of \(\approx \)0.05 is noticed. Therefore, the yield strain of \(\approx \)0.05 can be considered as a critical strain value below which Graphene does not show failure. This information can be utilized as a lower bound for the design of nano-devices for various strain sensor applications. Furthermore, the yield data will be useful while developing the Graphene coating on Silicon surface in order to enhance the mechanical and electrical characteristics of solar cells and to arrest the growth of micro-cracks in Silicon cells.     

Estimation of composite damage model parameters using spectral finite element and neural network

A multi-layer perceptron (MLP) network using error back propagation algorithm is employed in this paper to estimate the damage parameters from broad-band spectral data as diagnostic signal. Various existing models of damage in laminated composite and the resulting stiffness degradation are discussed from comparative view-point. Degradation of ply properties can be considered to be one of the damage model parameters while monitoring transverse matrix cracks in cross-ply, splitting in longitudinal ply, and evolution of consecutive stages of damage, such as delaminations and fiber fracture. The stiffness degradation factor, the location and size of the damaged zone in laminated composite beam are considered as damage model parameters in the present paper. Fourier spectral data, which is typical to most of the diagnostic wave measurements, are used as input to the neural network. Since, training the neural network in such case involves many data sets and all of these data are difficult to generate using experiments, a spectral finite element model (SFEM) with embedded degraded zone in laminated composite beam is developed. Numerical simulation using this element is carried out, which shows the nature of temporal signal that are likely to be measured. Analytical studies on the performance of the neural network are presented based on numerically simulated data. Effect of measurement noise on the network performance is also reported.     

Delta-opioid stimulation by BW373U86 promotes autonomic reactivity to stressors and alters attention-related cardiac responses in rabbits.

The nonpeptide δ-opioid agonist BW373U86 (3 to 300 μg/kg) was tested in rabbits for effects on heart rate, cardiac orienting and Pavlovian conditioned responses to tones, and unconditioned cardiac and somatomotor responses to signaled and unsignaled shocks. BW373U86 did not alter shock-evoked somatomotor reflexes and had few effects on the development or retention of Pavlovian conditioned heart rate discrimination. However, BW373U86 appeared to modulate cardiac conditioning indirectly, by facilitating sympathetic reflexes evoked by the signaled stressor, and the dose effect was ∪-shaped within the dose range tested. The pronounced tachycardiac effect of BW373U86 was completely blocked, or rapidly reversed, by the selective δ-opiate antagonist naltrindole. BW373U86 was more potent in increasing signaled than unsignaled shock-evoked tachycardia, suggesting release of an endogenous substance (e.g., a δ-opioid) because of the Pavlovian conditioning contingency. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence of Coating Granulation Process on Iron Ore Sinter Quality and Productivity

For better blast furnace performance, there has always been a need for better quality raw materials like sinter, lump ore, and pellets. Among these raw materials the usage of sinter in blast furnace is at higher side compared to other iron bearing materials. As the quality of sinter product improves, its usage in blast furnaces also increases. Iron ore fines are the main source for sinter making. To improve the sinter properties it is necessary to provide good quality of iron ore fines. Due to depletion of high grade iron ore resources, goethite and limonitic ore content in iron ore fines is expected to increase gradually. Usually limonitic and goethite ore are associated with higher alumina and LOI. The conventional sintering process is one of the well established processes for high quality hematite ore. It does not fully respond to the low grade iron ore associated with goethite and limonite. This has led to deterioration in sinter properties and productivity. In recent years the improvement in the quasi‐particle structure with the granulation process is an effective method for improving sinter quality and productivity. To improve the sinter quality and productivity for low grade iron ore fines, different granulation processes like the conventional one, and other two advanced granulation processes like coke breeze, and flux & coke breeze coating granulation were studied in detail by conducting laboratory pot grate sintering experiments. From the test results it was found that sinter productivity, physical and metallurgical properties of the sinter improved with flux & coke breeze coating granulation process compared to conventional and coke breeze coating granulation process. Proper selection of the granulation time is very important to achieve the desired sinter properties. In the present work detailed laboratory experiments have been carried out by varying the coating time from 30s to 110s to study the influence of flux & coke breeze coating granulation time on mineralogy, productivity, physical, and metallurgical properties of sinter. With a coating granulation time of 50s, higher productivity, higher yield, and stronger sinter (higher T.I) with lower RDI and ‐5mm size sinter were achieved.     

Solitary giant skull base schwannomas--report of four cases

BACKGROUND: Solitary intracranial schwannomas not related to major nerves or neurofibromatosis as well as paranasal schwannomas are rare. Schwannomas simultaneously involving the paranasal sinuses and intracranial cavity are even rarer. METHODS: We report four cases of schwannomas simultaneously involving the intracranial cavity and paranasal sinuses. They were successfully managed by surgery. The literature on such tumors is reviewed. RESULTS: All patients were young adults; the male to female ratio was 1:3. In two patients, the tumor was predominantly intracranial with extension into the sphenoid and ethmoid sinuses, whereas in the other patients, the tumor was located predominantly in the paranasal sinuses and nasopharynx with intracranial extension. Radiologically, bone destruction was seen in three cases. The tumors were totally removed piecemeal with repair of the basal dura. Histopathologic examination confirmed the diagnosis of schwannoma in all four cases. Three patients are alive and well; one of them was reoperated for a recurrence. CONCLUSIONS: These tumors should be excised completely if possible. Radiologically, bone erosion or destruction are suggestive of malignancy but histopathology clinches the diagnosis. Therefore, drastic surgery should be avoided in these cases. Surgery is generally curative in these massive schwannomas.     

Study on body mass index, lipid profile and lipid peroxidation status in coronary artery disease

Among the many known risk factors of coronary artery disease (CAD) obesity and hypercholesterolaemia are important ones. Whatever may be the risk factor, the basic pathology of CAD is deposition of altered lipids on the endothelium. One of such altered lipid is oxidatively modified low density lipoprotein (LDL). Lipid peroxidation has been assessed by several methods. Quantitation of malondialdehyde (MDA) by thiobarbituric acid (TBA) method is one of the commonly utilised method in several laboratories. In this study 40 cases of CAD were selected for evaluation. The body mass index (BMI), lipid profile and the level of lipid peroxidation (MDA) were measured. Seventeen cases (42.5%) had normal BMI (20-25), 20 cases (50%) were in the overweight range of BMI (26-30) and only 3 cases (7.5%) were in the obese group with a BMI more than 30. BMI correlated better with the level of total cholesterol (Tc), low density lipoprotein cholesterol (HDLc) and MDA. BMI did not show any correlation with triglyceride (Tg) or high density lipoprotein cholesterol (HDLc). MDA level correlated better with Tc, Tg levels and BMI, poorly correlated with LDLc and in inverse relationship was observed with HDLc.     

Recent progress on commercialization of castrip® direct strip casting technology at Nucor Crawfordsville

The world’s first commercial installation for direct casting of low-carbon steel sheet utilizing CASTRIP® technology is undergoing production ramp-up at Nucor Steel’s plant in Crawfordsville, Indiana. Construction of the plant was initiated in February 2001 and the first ladle was delivered to the caster in May 2002. Since that time, Nucor Steel has been working with technology partners BlueScope Steel (formerly BHP Steel) and IHI (Ishikawajima-Harima Heavy Industries) to fully commercialize this exciting new technology for the direct production of steel sheet less than 2 mm in thickness.