Evaporative heat and mass transfer from the free surface of a liquid wicked into a bed of spheres

Evaporation of ethanol from square packed arrays of 3.95 mm diameter copper spheres in a transparent, enclosed chamber is investigated. The enclosure ensures that relatively saturated vapor conditions exist near the free surface. The desired heat flux is imposed on the copper substrate upon which the copper spheres are mounted, and the liquid level in the bed is maintained by wicking from a continuous supply of liquid provided by a syringe pump. Transparent windows in the enclosure allow for visualization of the evaporating liquid meniscus shape, which is recorded for different liquid feeding rates and heat fluxes. Experimentally measured meniscus profiles are compared to analytical results based on surface-energy minimization. A meniscus microregion is defined from the contact line to the length where the liquid thickness reaches 10 μm. An approximate kinetic theory-based analysis estimates that up to ～55% of the total meniscus mass transfer occurs in this microregion.     

Developments in low-cost housing

The co-ordinator of working group W63 shows, in this abridged version of his paper, how several countries have brought a degree of pragmatism to their innovations, which take account of the realities of their situation in terms of material and manpower resources and the level of technology appropriate to their needs.     

Wave Interaction with a Flexible Porous Breakwater in a Two-Layer Fluid

An analysis has been carried out to study the performance of a flexible porous plate breakwater in a two-layer fluid where each fluid is assumed to be of finite depth and the breakwater is extended over the entire water depth. The problem is analyzed in two dimensions with the assumption of small amplitude wave theory and plate response. The effects of both surface and internal waves are taken into account in the present study. The associated mixed boundary value problem is reduced to a linear system of equations by utilizing a more general orthogonal relation along with least squares approximation method. The reflection and transmission coefficients for the surface and internal modes, wave load, and breakwater response are computed for various physical parameters of interest to analyze the efficiency of the flexible porous plate as a breakwater in the two-layer fluid.     

STRANDS: Interactive Simulation of Thin Solids using Cosserat Models

Strands are thin elastic solids that are visually well approximated as smooth curves, and yet possess essential physical behaviors characteristic of solid objects such as twisting. Common examples in computer graphics include: sutures, catheters, and tendons in surgical simulation; hairs, ropes, and vegetation in animation. Physical models based on spring meshes or 3D finite elements for such thin solids are either inaccurate or inefficient for interactive simulation. In this paper we show that models based on the Cosserat theory of elastic rods are very well suited for interactive simulation of these objects. The physical model reduces to a system of spatial ordinary differential equations that can be solved efficiently for typical boundary conditions. The model handles the important geometric non‐linearity due to large changes in shape. We introduce Cosserat‐type physical models, describe efficient numerical methods for interactive simulation of these models, and implementation results.     

Application of Sequential Learning Neural Networks to Civil Engineering Modeling Problems

A sequential orthogonal approach to the building and training of a single hidden layer neural network is presented in this paper. The Sequential Learning Neural Network (SLNN) model proposed by Zhang and Morris [1]is used in this paper to tackle the common problem encountered by the conventional Feed Forward Neural Network (FFNN) in determining the network structure in the number of hidden layers and the number of hidden neurons in each layer. The procedure starts with a single hidden neuron and sequentially increases in the number of hidden neurons until the model error is sufficiently small. The classical Gram–Schmidt orthogonalization method is used at each step to form a set of orthogonal bases for the space spanned by output vectors of the hidden neurons. In this approach it is possible to determine the necessary number of hidden neurons required. However, for the problems investigated in this paper, one hidden neuron itself is sufficient to achieve the desired accuracy. The neural network architecture has been trained and tested on two practical civil engineering problems – soil classification, and the prediction o strength and workability of high performance concrete.     

Nonliposomal approach--a study of preparation of egg albumin nanospheres containing amphotericin-B

The stability of liposomes after introduction into the body is presently being discussed and needs thorough understanding. Hence, as a nonliposomal approach, egg albumin nanospheres were prepared by the pH-coacervation method, and a preliminary study was carried out of the influence of process variables on the size and shape of nanospheres by changing the pH of the albumin solution, concentration of albumin solution, and volume of cross-linking agent. The batch prepared with an albumin medium of pH 9, 2% concentration, and 100 μl of 4% glutaraldehyde-ethanol solution was found to have a spherical uniform shape with an average size of 497.6 nm. The ideal batch was loaded with the systemic antifungal drug amphotericin-B. Drug-loaded nanospheres were evaluated to study their in vitro release. They were found to exhibit a biphasic pattern with a cumulative percentage release of 97.7%.     

Ab initio modelling of basal plane oxidation of graphenes and implications for modelling char combustion

Ab initio calculations have been performed to determine the energetics of oxygen atoms adsorbed onto graphene planes and the possible reaction path extracting carbon atoms in the form of carbon monoxide. From the energetics it is confirmed that this reaction path will not significantly contribute to the gasification of well ordered carbonaceous chars. Modelling results which explore this limit are presented.     

Network architecture and communication protocols for mobile computing

We discuss the design and implementation of network and transport layer protocols for mobile networking. The network architecture used is unique in that it separates the mobile network(s) from fixed networks and provides connectivity between the two via special gateways. These gateways split all transport connections and provide QoS guarantees to mobile users for all their open connections. We provide summaries of our protocols and discuss possible improvements.     

Applicability of selected probability distributions to the number of authors per article in theoretical population genetics

Recently scientists have investigated what statistical distributions can be used to describe the distribution of the number of authors per article.Ajiferuke has undertaken the most comprehensive study of this problem. He has found that by and large the Inverse Gaussian-Poisson distribution could describe most properly the observed authorship distributions. However, it is well known that this distribution is rather intricate, soRousseau tried to fit some simple one-parameter distributions to the number of authors of LIS articles. He has found that the geometric and the truncated Poisson distribution adequately describe these authorship data sets. The main purpose of the present paper is to continue these investigations and to analyse and test the viability of simple statistical distributions. As to (sub)fields where the single author dominates the results ofRousseau were corroborated: the truncated Poisson and the geometric distribution give often adequate fits to describe the number of authors. The Lotka distribution should be rejected. The truncated binomial distribution and the truncated negative binomial were investigated as well. However, it is not clear whether they are acceptable candidates.     

Characterization of sputtered SmCo thin films for light element contamination using RBS and HIERDA techniques

Samarium cobalt films were prepared on silicon substrates with and without a chromium buffer layer at room temperature and 600°C using direct current unbalanced magnetron sputtering. For obtaining ideal magnetic properties, the films should be free from impurities, such as O, Al and others. Rutherford backscattering spectrometry and heavy ion elastic recoil detection analysis were used to determine the composition and film thickness and to monitor the light element contamination across film thickness. X-ray diffractometer and superconducting quantum interference device were employed to characterize the structure and magnetic properties of the films, respectively. The results obtained led to an improved design of the ground shield and the use of a sorption pump to effectively minimize aluminium and oxygen concentration in the films, respectively.