Free vibration analysis of variable thickness thin plates by two-dimensional differential transform method

This paper aims at extending the application of two-dimensional differential transform method (2D-DTM) to study the free vibration of thin plates with arbitrarily varying thickness. First, the differential equation of motion governing thin plates with varying thickness is derived using Hamilton’s principle. Afterward, the 2D-DTM, a numerical method which is capable of reducing the size of computational work and can be applied to various types of differential equations, has been applied to derive the natural frequencies of variable thickness thin plates with different boundary conditions. Several numerical examples have been carried out to demonstrate the applicability and accuracy of the present method in free vibration analysis of both uniform plates and plates with variable thickness.     

Serotonin transporter gene associations with psychopathic traits in youth vary as a function of socioeconomic resources.

Although prior research has examined the genetic correlates of antisocial behavior, molecular genetics influences on psychopathic traits remain largely unknown. Consequently, we investigated the influence of polymorphic variation at the serotonin transporter protein gene (SLC6A4) and socioeconomic resources (SES) on psychopathic traits in youth across two distinct samples in two separate studies. In Study 1, a main effect of serotonin transporter (5-HTTLPR) genotype was associated with the impulsivity dimension of psychopathy. That is, individuals homozygous for the short allele evidenced more impulsivity than did those homozygous for the long allele. In contrast, a gene–environment interaction was associated with the callous-unemotional and narcissistic features of psychopathy. Callous-unemotional and narcissistic traits increased as SES decreased only among youths with the homozygous-long (l/l) genotype, a novel finding replicated and extended in Study 2. These studies provide preliminary results that the l/l genotype confers risk for the emotional deficits and predatory interpersonal traits associated with psychopathy among youths raised in disadvantaged environments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Foliar Application of Nano-Silicon Complexes on Growth,Oxidative Damage and Bioactive Compounds of Feverfew Under Drought Stress

Silicon - Drought stress limits the growth and yield of essential oils of valuable medicinal plants such as feverfew (Tanacetum parthenium). So, foliar application efficiency of nano-silicon...     

Nanocomposites of poly(vinylidene fluoride) with multiwalled carbon nanotubes

The preparation and characterization of nanocomposites of poly(vinylidene fluoride), PVDF, with acid treated multiwalled carbon nanotubes (MWCNT) with a wide composition range, from 0.1 to 5.0% MWCNT by weight, is reported. Effect of uniaxial orientation by zone drawing on these nanocomposites is discussed and compared with unoriented compression molded films. Static room temperature two‐dimensional wide angle X‐ray scattering and Fourier transform infrared spectroscopy were used for phase identification. Differential scanning calorimetry, polarizing optical microscopy, dynamic mechanical analysis (DMA), and thermogravimetic analysis (TGA) were used to study the thermal and mechanical properties. Incorporation of MWCNT into PVDF has no obvious effect in forming beta phase crystal in the PVDF/MWCNT bulk films, while zone drawing cause a significant alpha to beta transition in PVDF/MWCNT. Results indicate that MWCNTs act as nucleation agent during crystallization and slightly increase the degree of crystallinity of PVDF/MWCNT bulk films. TGA indicates the thermal stability is improved when MWCNT concentration increases for unoriented PVDF/MWCNT film. The modulus also increases significantly when MWCNT concentration increases. The glass transition temperature measured by the peak position of tanδ from DMA does not change with MWCNT concentration, but a slightly higher glass transition can be obtained by zone drawing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of carbon nanotube and aluminum oxide addition on plasma-sprayed hydroxyapatite coating's mechanical properties and biocompatibility

This study reports on the synthesis of novel bioceramic composite coating of hydroxyapatite (HA) reinforced with carbon nanotubes (CNTs) and aluminum oxide (Al₂O₃) using plasma spray technique. Fracture toughness of HA–20 wt.% Al₂O₃ improved by 158% as compared to HA coating whereas HA–18.4 wt.% Al₂O₃–1.6 wt.% CNT showed an improvement of 300%. Carbon nanotubes provided reinforcement via rebar mechanism. Human fiber osteoblast cell-growth studies showed that biocompatibility of the coating remained unaltered, as Al₂O₃ retained its bio-inertness and CNT, its bioactivity, within the composite coatings. Composite coating showed lower attachment, but higher proliferation rate, for the osteoblast cells, which has been attributed to the surface roughness. An optimized relation between coating composition, its biocompatibility and mechanical properties was established to predict the most suited coating material for orthopedic implants. HA–Al₂O₃–CNT composite coating displayed most improved mechanical properties while retaining its biocompatibility.     

Introduction to Special Issue on New Paradigms in Intelligent Spectrum Management

International Journal of Wireless Information Networks -     

Synthesis and Characterization of the New Nano Flowers Lead(II) Coordination Polymer with Hemidirected Coordination Sphere

Nano flowers of a new polymeric lead(II) complex containing the azide anions, [Pb(baea)(N₃)·(N₃)] _n (“baea” is the abbreviation of bis(2-aminoethyl)amine), has been synthesized by a sonochemical method. The new nano-structure was characterized by transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, elemental analyses, and IR spectroscopy. Single crystalline material was obtained using a heat gradient applied to a solution of the reagents. Single-crystal X-ray diffraction analyses show that the coordination number for Pb^II ions is five, PbN5 and hold hemidirected coordination geometry. To the best of our knowledge, the 1D coordination polymer interact with each other via supramolecular and weak Pb···N interactions to create 2D supramolecular frameworks.     

A mathematical model for order splitting in a multiple supplier single-item inventory system

In this paper we develop a mathematical model which considers multiple-supplier single-item inventory systems. The lead times of the suppliers and demand arrival rate are random variables. All shortages are backordered. Continuous review (s, Q) policy has been assumed. When the inventory level hits the reorder level, the total order is split among n suppliers. The problem is to determine the reorder level and order quantity for each supplier so that the expected total cost per time unit, including ordering cost, procurement cost, inventory holding cost and shortage cost is minimized. We also conduct extensive numerical experiments to show the advantages of our model compared to the relevant models in the literature. In addition, some managerial insights are observed.     

利用混合信号FPGA推动临床医疗应用设备的发展

本文提出利用混合信号FPGA推动临床医疗应用设备的发展,它所具备的优势有助于临床医疗设备满足电池规范,减小占用面积,将热耗散降至最低并确保其可靠运作.