A general finite element model for shells of arbitrary geometry

A finite element formulation is developed for the large displacement analysis of arbitrary shells. Formulation is based on a convected coordinate system and a tensorial approach is followed. The strain-displacement relationships used do not reflect the Kirchhoff hypothesis and Love's approximations. Isoparametric interpolation is used for the discretization of the problem, and the number of nodal points is variable. The numerical examples include the buckling analysis of cylindrical shells as well as two problems to test the convergence and accuracy of the algorithm.     

A High-Speed Low-Power Divide-by-15/16 Dual Modulus Prescaler in 0.6 μm CMOS

A new high-speed low-power dual modulus prescaler (DMP) topology is proposed. In this DMP, the synchronous part is designed as a divide-by-3/4 divider using a state-selection scheme. Compared with the conventional divide-by-4/5 divider, it has a higher speed by eliminating the NAND-gate introduced critical path delay, as well as a lower power consumption by minimizing the number of full-speed D-type flip-flops (DFF's) required. Based on this topology, a divide-by-15/16 DMP is implemented in the 0.6 m standard CMOS process. Simulation result shows that a maximum operating frequency of 2.15 GHz is obtained at 3.3 V supply with a power consumption of 11.6 mW. The circuit can operate above 3 GHz with 5 V supply and down to 1.5 V supply voltage with 570 MHz input frequency.     

Domestic Arrangements: The Maid's Room in the Ataköy Apartment Blocks,Istanbul, Turkey

The first phase of Istanbul's Ataköy Housing Development, an icon of architectural modernism in Turkey, inflects modernist architectural forms with local domestic traditions. This study examines the maid's room, a sphere of the Turkish modern interior where post-war ideas and ideals both reconciled and contradicted the customary and the modern. The case study extends recent attempts to re-think postwar architectural culture and its global effects.     

A spin wave resonance study on reentrant Au77Fe23 films

Thin films prepared by both flash and slow evaporation of the bulk Au₇₇Fe₂₃ alloy have been studied by electron spin resonance (ESR) technique at the temperature range between 77–300 K. A series of spin wave resonance (SWR) peaks were observed at all temperatures when the external de magnetic field is applied along the directions lying in a small angular interval with respect to the film normal. The classical spin wave model has been used to analyze the experimental data. The magnetic parameters, such as exchange stiffness constant, the effective bulk and the surface anisotropy energy parameters of the system have been derived as a function of temperature. While the easy plane surface anisotropy almost remains constant, considerable increments were found in the exchange parameter, the magnetization and the linewidth with decreasing temperature. The SWR linewidths for the films obtained by slow evaporation at higher substrate temperatures are noticeably smaller compared to those of the film prepared by flash evaporation technique.     

Stress-Strain State of Soils Under Thin Shell Structures with Infill

Soil Mechanics and Foundation Engineering - The article presents the investigations of the stress-strain conditions at the foundation of structures made of thin shells with infill. A finite element...     

Nonzero Mean Oscillatory Flow in Symmetrically-Heated Shallow Enclosures: An Analysis of Acoustic Streaming

The effects of symmetric heating on a nonzero mean oscillatory fluid motion, namely acoustic streaming, in air-filled shallow enclosures and associated thermal convection in transient regime are investigated numerically. The fluid motion is driven by periodic vibration of the enclosure left wall. The vertical walls of the enclosure are adiabatic while the horizontal walls are heated symmetrically. A control-volume method-based explicit time-marching flux-corrected transport algorithm is used to simulate the transport phenomena in the enclosure. A symmetric temperature gradient strongly affects the acoustic streaming structures and velocities. The variation of the steady flow field becomes more noticeable and drastic with increasing wall temperature.     

The role of political risk in service offshoring entry mode decisions

This research investigates the effect of political risk on the offshore service industry. The study empirically examines how an extended political risk definition, operationalised into a model consisting of 12 political risk variables, helps predict location decisions across offshoring entry modes and activity types. The research focuses on captive offshoring and offshore outsourcing entry modes, and Information Technology Outsourcing (ITO), Business Process Outsourcing (BPO) and Knowledge Process Outsourcing (KPO) activity types. The research indicated that political risk factors accounted for 38% of the variability in offshore outsourcing flows, implying that concerns about service disruptions and/or cost implications of external uncertainties feature as a key factor in supplier selection and location decisions. The findings further confirm a positive relationship between institutional and regulatory factors in host locations, and the flow of offshoring activities with a high knowledge content. The research contributes to enhancing the explanatory ability of Transaction Cost Economics by re-operationalising the concept of political risk in the context of both offshore outsourcing and captive offshoring. For practitioners, these findings provide a clear indication of the political risks that can affect service offshoring decisions; for policymakers, they highlight the importance of strengthening institutional and regulatory factors to attract investment.     

Dual Activators of Protein Kinase R (PKR) and Protein Kinase R‐Like Kinase (PERK) Identify Common and Divergent Catalytic Targets

Chemical genetics has evolved into a powerful tool for studying gene function in normal and pathobiology. PKR and PERK, two eukaryotic translation initiation factor 2 alpha (eIF2α) kinases, play critical roles in the maintenance of cellular hemostasis, metabolic stability, and anti‐viral defenses. Both kinases interact with and phosphorylate additional substrates including tumor suppressor p53 and nuclear protein 90. Loss of function of both kinases has been studied by reverse genetics and with recently identified inhibitors. In contrast, no activating probes for studying the catalytic activity of these kinases are available. We identified 3‐(2,3‐dihydrobenzo[b][1,4]dioxin‐6‐yl)‐5,7‐dihydroxy‐4H‐chromen‐4‐one (DHBDC) as a specific dual activator of PKR and PERK by screening a chemical library of 20 000 small molecules in a dual luciferase surrogate eIF2α phosphorylation assay. We present here extensive biological characterization and a preliminary structure–activity relationship of DHBDC, which phosphorylates eIF2α by activating PKR and PERK but no other eIF2α kinases. These agents also activate downstream effectors of eIF2α phosphorylation by inducing CEBP homologue protein, suppressing cyclin D1 expression, and inhibiting cancer cell proliferation, all in a manner dependent on PKR and PERK. Consistent with the role of eIF2α phosphorylation in viral infection, DHBDC inhibits the proliferation of human hepatitis C virus. Finally, DHBDC induces the phosphorylation of IκBα and activates the NF‐κB pathway. Surprisingly, activation of the NF‐κB pathway is dependent on PERK but independent of PKR activity. These data indicate that DHBDC is an invaluable probe for elucidating the role of PKR and PERK in normal and pathobiology.