An eight‐node hybrid‐stress solid‐shell element for geometric non‐linear analysis of elastic shells

This paper presents eight‐node solid‐shell elements for geometric non‐linear analysis of elastic shells. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. A selectively reduced integrated element is formulated with its membrane and bending shear strain components taken to be constant and equal to the ones evaluated at the element centroid. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger–Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid element, a hybrid‐stress solid‐shell element is formulated. Commonly employed geometric non‐linear homogeneous and laminated shell problems are attempted and our results are close to those of other state‐of‐the‐art elements. Moreover, the hybrid‐stress element converges more readily than the selectively reduced integrated element in all benchmark problems. Copyright © 2002 John Wiley & Sons, Ltd.     

Simple concepts for ion source improvement

We report on improvements in the overall intensity of a sputter ion source that evolved originally from an NEC MCSNICS. Beam output increases benefit both AMS measurements and nuclear physics experiments using low natural abundance beams. In particular, minor changes in source geometry suggested by a combination of electrostatic calculations and simple design principles have yielded increases in extracted negative ion intensity of nearly a factor of 4.     

Creating and Justifying Research and Development Value: Scope,Scale, Skill and Social Networking of R&D

In this paper we describe a framework for analysing the creation and justification of Research & Development. The 4S framework is developed for analysing the scope, scale, skills and social network aspects of Research & Development value. The framework is based on social system theory, a process contingency model, and recent Research & Development metrics. We present a first empirical assessment based on a workshop using the 4S framework for leveraging Research & Development. Results that assist in the assessment of value creation utilising R & D within networks are very relevant in high tech industries. The multi–dimensional process approach of this framework seems promising for understanding and managing R&D value creation, but needs further operationalisation. Case studies are described and a Dutch network on leveraging R&D has been initiated.     

HYDCOND: A Computer Program to Calculate Hydraulic Conductivity from Grain Size Data in Saudi Arabia

Hydrogeologists always look for reliable techniques to determine the hydraulic conductivity of the aquifers with which they are concerned, for better groundwater management and conservation. The use of grain size distribution for unconsolidated aquifer materials is considered feasible and sound. Several empirical equations to calculate hydraulic conductivity using grain size distribution are well established in the literature. The present paper describes a computer program, HYDCOND, which is designed to calculate hydraulic conductivity using grain size data. In addition, the program calculates grain size statistics and classifies the aquifer materials in terms of their main size percentage. HYDCOND is menu-driven, interactive and user friendly program. It was tested extensively and successfully using materials from Minjur aquifer in central Saudi Arabia. The results were found to be reliable and comparable to those obtained using other, costly techniques. HYDCOND can be implemented successfully to calculate hydraulic conductivity in all types of aquifers in Saudi Arabia and other regions of the world.     

ROLE OF COMPOSITION ON THE VISCOSITY AND SHEAR STRESS TEMPERATURE BEHAVIOUR OF SOME LUBE OIL BASE STOCKS

Lubricating oil base stocks differ greatly in their chemical composition and consequently in their physical properties and applications. Influence of waxes and various hydrocarbon type constituents viz saturates and aromatic components on the viscosity and shear stress as a function of temperature in different lube oil base stocks has been studied in the present paper.     

Wide-band polarization-independent tensile-strained InGaAs MQW-SOAgate

A high-performance tensile-strained InGaAs multi-quantum-well semiconductor optical amplifier (MQW-SOA) gate developed for wavelength-division-multiplexing (WDM) applications is reported. The -0.47% InGaAs-strained SOA gate has a very low polarization dependence of 0.3 dB over a driving current between 30 and 60 mA and a wide-input signal wavelength range from 1530 to 1580 nm. The fabrication tolerance of the mesa stripe width is very large, ranging from 1.0 to 1.75 μm. The MQW-SOA gate has an extinction ratio of more than 40 dB. The fiber-to-fiber lossless operation current is less than 50 mA over the fiber-amplifier gain band. The gating speed is less than 1 ns     

Construction and Preliminary Performance of Reedbed Treatment Systems at Castle Espie Wildfowl and Wetlands Trust Centre, Northern Ireland

In 1993, the Wildfowl and Wetlands Trust constructed a demonstration reedbed treatment system at its Castle Espie Visitor Centre in Northern Ireland. The objectives of the project included (a) the treatment of septic-tank effluent, (b) the protection of water quality in Strangford Lough, and (c) the establishment of a research base for constructed wetland systems. Parallel beds of equally sized sub-surface and surface flow were constructed and planted, and a research project was initiated to provide data on performance.     

Reconstruction and rehabilitation of short-range, high-velocity gunshot injury to the lower face: a case report

BACKGROUND: Germ cell tumors (GCTs) and their metastases may be found in numerous sites that are accessible to cytologic sampling, and many are responsive to chemotherapy. METHODS: The authors reviewed 20 examples of GCT cytology from 16 males and 3 females ranging in age from 1.5 to 61 years (median, 34 years). With two exceptions, one benign cystic ovarian teratoma in which intraoperative cytology was used to diagnose an associated adult-type carcinoma and one undescended testis in which seminoma presented as an abdominal mass, the material reviewed included no examples of primary gonadal GCT. RESULTS: The authors studied 7 primary and 13 metastatic GCTs; these studies were based on 13 in vivo aspirations, 4 intraoperative preparations, and 3 samples of body cavity fluids. All samples were correctly interpreted as malignant, and only one was incorrectly classified as a non-GCT malignancy. CONCLUSIONS: Clinical and cytologic findings are useful in the diagnosis of GCTs and their metastases. Incorrect interpretation of these neoplasms as poorly differentiated malignancies of other types may deprive the patient of effective chemotherapy. Air-dried, Romanowsky-stained smear material and cell block sections may contribute to the resolution of diagnostic dilemmas.     

Efficient performance analysis of asynchronous cellular CDMA overRayleigh-fading channels

The bit error rate (BER) analysis of a direct-sequence code-division multiple-access (DS-CDMA) cellular system over a Rayleigh-fading channel often results in complicated expressions even though the Gaussian approximation is applied. A combined probability density function (pdf) approach for the forward link and a mean-method technique for the reverse link are proposed to significantly reduce the computational complexity. The simplified BER expressions are derived and yield accurate results