bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Low Level Wind Behaviour in Central and South East Malta
Authors: Gago Rodrigo Cabornero , Farrugia Robert N. , Giordmaina Lawrence , Galdies Charles
Published: August 2010

The main objective of this study was to investigate low level wind behaviour at five locations in the central and South East parts of the Mediterranean island of Malta. The datasets covered a period of 12 months spanning from November 2007 to October 2008. The results showed similar wind speed trends; a feature that may, to a certain extent be attributed to the relative proximity of the locations being studied. The monitoring height and the exposure of the wind measurement sensors were important factors to be kept in mind when comparing wind behavioural characteristics. As expected, the site with the highest instrument cluster exhibited noticeably higher wind speeds than the rest of the locations. The wind monitoring stations were in open, built or semi-built environments and the results generated should be useful to estimate performance characteristics of small wind turbines at similar locations.
Kathmandu Alternative Power and Energy Group: Our Experience in Promotion of Low Cost Wind Energy Technology in Nepal
Authors: Ghimire Pramod , Sharma Ranjan , Lamichhane Chudamani , Freere Peter , Sinha Rakesh , Acharya Parash
Published: August 2010

This paper describes the research and development activities carried out by Kathmandu Alternative power and Energy Group (KAPEG) in promotion of wind energy technology in Nepal. Based on the published report, a brief review of wind energy practices in Nepal is presented. The future opportunities in wind energy in Nepal are discussed. KAPEG's completed and ongoing activities in promotion of small scale wind energy are presented. KAPEG has been receiving significant technical and financial assistance from international partners to develop the expertise which is also discussed. Finally, based on the KAPEG experience some of the future works are recommended for the development of wind energy technology in Nepal.
A Survey on the Effect of Security Car Alarm Noise Pollution among Pupils in Tehran Schools
Authors: Monazzam Mohammad Reza , Boubehrej M. , Fard Samaneh M. B.
Published: August 2010

One of the most important noise pollution sources in almost all urban areas, which is security car alarm, is surveyed in this paper. The major aims of this research are determining the real function of car alarms as theft preventing devices and noise pollution imposed on the nearby residents including students and their families. In order to achieve those aims, a survey verified questionnaire has been designed including 9 questions and distributed in 7 regions of Tehran, Karaj and Islamshahr schools, 667 of which were collected. According to the survey, 90% of the subjects have never taken action and called police in a case of possible burglary while 66% percent of people have heard car alarms more than 3 times a day, two-thirds of them don't believe in the effectiveness of car alarms in preventing robbery. 76% of subjects complained of car alarm noise interference with their ability to sleep and 84% with their working and studying capabilities. They have also rated their annoyance from this kind of noise 6.2 which is above moderate level. In 13% of cases the worst and most bothering noise the people have ever experienced, are car alarm sirens and 52% is in some way related to traffic noise.
Wind Power Characteristics on the North West Coast of Saudi Arabia
Authors: Rehman Shafiqur , Al-Abbadi Naif M.
Published: August 2010

Measured values of wind speed at 20, 30 and 40 meters above ground level along with other meteorological parameters were used to study the wind characteristics and wind energy yield. The measured data covered a period of almost 36 months between September 17, 1996 and October 21, 1999. Almost identical annual mean wind speeds were found at different heights with a very small value of wind shear exponent of 0.062. Weibull parameters were found to be real representatives of the actual wind frequency distribution. The selected wind turbine of 2.75 MW rated capacity could produce annually 6,681; 6,875 and 7,049 MWh of electricity with an average plant capacity factor (PCF) of 27.7, 28.5 and 29.3% corresponding to hub heights of 60, 80 and 100 m, respectively.
Energy is the Key: Renewable Energy Problems in Germany
Authors: Limburg Michael
Published: August 2010

The basic requirements for a steady, demand-oriented, economic and environmentally compatible energy supply are defined and the electrical energy produced by wind, sun and bio-fuel are then rated accordingly. Although renewable energies have made considerable progress in some respects, they have major shortcomings when compared to conventional energy sources when all factors are considered. One of the main reasons is the extremely low energy density characteristic that renewable energy sources have. Another reason is the unsolved problem of the highly uneconomical large-scale storage of electrical energy, and with still no solution in sight. Bio-fuels can be stored and are thus an exception. But they have enormous problems in other areas. The deficiencies for all types of renewable energies are discussed in detail and illustrated with example calculations.
Estimating the Potential for Biogas Production and Application in Morogoro Region, Tanzania
Authors: Mkiramweni Langeni L.N. , Mshoro Idrissa B.
Published: August 2010

About 87% of Tanzanian households rely on energy from fuel-wood and charcoal for cooking. This threatens sustainability as annual deforestation currently stands at about 500,000 hectares. Biogas can be an alternative source, especially where there is potential, like in Morogoro region. Biogas is however not widely applied in Morogoro region and reliable data to show this effect quantitatively do not exist. This paper therefore attempts to fill the gap. The authors observe that up to 1.8 Giga m3 of biogas could be produced daily, surpassing by far the 93,000 m3 regional requirement for cooking. Considering corresponding calorific values of wood versus biogas and respective stove efficiencies, each household can realise up to US$ 724 by replacing wood use with biogas, apart from other positive impacts to the environment. Sensitisation should therefore be enhanced, and support services provided towards optimisation of the biogas production process so that potential benefits are realised.
The Current Status and Prospect of Biodiesel
Authors: Tao Jie , Dai Chuan-chao , Jiang Bao-juan
Published: August 2010

To address the constantly deteriorating situation of energy supply, the environment, and energy security, biodiesel is considered to be the most important biofuel of the future. However, the high cost of biodiesel inhibits it to become a viable alternative of petroleum-based fuel. As global demand for food is expected to double in next 50 years, food-based biodiesel appears to be an unwise choice. Therefore, biodiesel from lignocellulosic biowastes seems to be an attractive and promising alternative to crude oil because of its superior environmental benefits, economical competitiveness, and resource sustainability. More attention should be paid to microbial oil technology, as it needs virtually no additional farmland to convert agricultural residues and other lignocellulosic biomass into lipids.
High Temperature Gasification Technology Prospects for Palm Wastes in Tanzania
Authors: John G. R.
Published: August 2010

A thermal characteristics analysis of Tanzania's palm oil waste streams inclusive of the fibre, stem, branch, and shells for their suitability in the High Temperature Air/Steam Gasification (HTAG) is reported. Proximate analysis of the wastes reveals the energy content range from 15,000 kJ/kg to 25,000 kJ/kg. The wastes contain high alkaline oxides of potassium (K2O) and sodium (Na2O) that influence ash formation and behaviour, which affect equipment corrosion. The thermal degradation characteristics of palm waste system in application to HTAG suggest the main route of conversion to be during pyrolysis where 51% of the mass loss occurs as compared to 33% that occurred during the char degradation stage. The palm stem have comparative advantage to the other streams towards gasification. Its mass loss rate was about 9.90%/min.as opposed to 8.30% (branch), 6.60% (shell) and 4.50% (fibre) at a period of 30 minutes.
A Critical Discussion of the Stern and IPCC Analyses of Carbon Emission Mitigation Possibilities and Costs
Authors: Trainer Ted
Published: August 2010

Like the Stern Review the IPCC Working Group 3 Reports have been taken as showing that the greenhouse gas emissions problem can be solved at negligible cost, primarily by development of alternative energy technologies. The lengthy Fourth Assessment Report summarises the findings of many studies, rather than present analyses that can be clearly assessed. The argument in this paper is that most and probably all of the studies drawing conclusions about the mitigation potential of alternatives are invalid because they do not consider the possible limitations to renewable energy sources, nuclear energy and geo-sequestration. They are economic modelling studies which take the cost of a unit of carbon mitigation and multiply this by the amount of mitigation required, without regard to the difficulties and limits affecting the extent to which these sources can be scaled up. If the greenhouse problem is to be solved by resort to these technologies then the magnitude of the scale-ability problem is huge. This paper argues that there are major reasons why the alternatives cannot be scaled up sufficiently, and that it is not possible to explain how the anticipated 2050 energy budget could be met without exceeding safe greenhouse limits. If this analysis is sound Stern and the IPCC have been seriously misleading and the greenhouse problem cannot be solved at any cost in a society that is committed to affluent living standards and economic growth. The discussion accepts the climate science in both sources, and does not dispute the desirability of moving to renewable energy.
Twentieth Century Sources of Methane in the Atmosphere
Authors: Quirk Tom
Published: August 2010

The role of methane in the atmosphere has been emphasised by the IPCC to the point that many governments regard methane as almost as important as carbon dioxide amongst the greenhouse gases. The IPCC emphasis has resulted in emissions from natural gas pipelines, coal seams and agricultural livestock being included in schemes to limit the growth of greenhouse gas concentrations. Analysis of changes to atmospheric methane within the last one hundred years suggests that the annual increases from 1930 to 1970 were due to losses from the production, transmission and distribution of natural gas. Further, the substantial reduction in these losses from 1970 to 1990 has brought the annual increases back to the rate seen at the start of the twentieth century. Measurements over the last fifteen years show only natural variability. They provide no justification for any attempts to reduce methane from industrial or agricultural activity. While methane variability remains restricted to natural causes, the best policy is to do nothing.
More Efficient Operation of Coal Fired Power Plants Using Nonlinear Models
Authors: Bulsari Abhay , Wemberg Antti , Anttila Ari , Multas Ahti
Published: August 2010

Coal fired power plants should be operated in such a way that the emissions are kept clearly below desired limits and the combustion efficiency is as high as can be achieved. This requires a lot of quantitative knowledge of the effects of the process variables and fuel characteristics on the emissions and efficiency. Mathematical models can be developed with different approaches. Physical models are too slow to be used for on-line process guidance, and require too many assumptions and simplifications. It is feasible to develop empirical or semi-empirical models from normal production data of the power plant. This technical communication explains with an example of a coal fired power plant how nonlinear models are an effective means of determining the best operating conditions at any given load for a given type of coal.
Behaviour of Repaired Concrete Filled Steel Tubular Column to Steel Beam Joints after Exposure to Fire
Authors: Huo Jing-Si , Han Lin-Hai , Wang Yong-Chang
Published: August 2010

This paper presents the test results and finite element analysis of eight tests. Each test specimen consisted of a concrete filled steel tubular (CFST) column connected by rings to two steel beam segments on each side to represent an interior joint in a building. Except for one test specimen, all the test specimens had been exposed to fire attack under unloaded condition and the fire distorted steel beams and the connecting rings had been replaced by new ones, simulating one possible retrofitting strategy. The test parameters included the column cross-sectional type (3 circular and 5 square), the level of axial load in the column, the beam-column strength ratio and the fire duration time. The applied load in the specimen was a constant axial load in the column followed by a cyclically lateral load applied to the connected beams with increasing amplitude until failure. A refined nonlinear finite element model was developed to analyze the load versus deformation relation of the test specimens. Approximate Updated Lagrangian (UL) formulations were adopted to obtain the stiffness matrix, in which both material and geometric nonlinearities of the structural elements were considered. Comparisons between the test and finite element simulation results show good agreement, which enables the finite element model to be applied in further research studies of earthquake-resistant behaviour of retrofitted fire damaged concrete-filled steel tubular structures.
Wedge Design: A Reduced Beam Web (RBW) Connection for Seismic Regions
Authors: Hedayat Amir A. , Celikag Murude
Published: August 2010

After the Northridge earthquake, it became clear that welded flange-bolted web connections for deep beams do not have adequate ductility when subject to seismic loading. Previous experimental tests on two such connections for shallow beams based on “wedge design” had achieved adequate strength and ductility. Such beams have a wedge removed from the web and flanges are then reattached. This study aimed to investigate the strength and ductility of “wedge design” connections for deep beams. The finite element method was used to model two pre-tested post-Northridge connections for deep beams of different depths. Wedge design was then applied on these connections, with results showing inadequate connection ductility. A parametric study was therefore carried out to find the best wedge detail. The effects of using different stiffener configurations and double wedge details on the strength, ductility and initial stiffness of connections were also investigated. Finally, the most effective stiffener configuration for the connection is proposed.
Experimental Research on and Application of Twice-Prestressed Concrete Beam
Authors: Shao Xudong , Yang Jianjun , Zhao Hua , Zhou Yadong , Nie Meichun
Published: August 2010

High prestressing stress and concrete creep create many problems for the designing of small and medium span prestressed concrete bridges, such as the inverse camber being too large and curved beams bending laterally. A high camber is also not permitted for the reasons of safety and comfort. To solve these issues, the new concept of twice-prestressed concrete beam is discussed in this paper. Theoretical and experimental comparisons between this new beam and the conventional prestressed beam show that the application of twice prestressing technology can greatly improve the mechanical and deformation performance for small and medium span prestressed concrete bridges. The paper also presents computational formula derived by the authors to calculate creep strain and deformation of a twice-prestressed concrete beam over time and an experiment which was carried out to verify the correctness of these formulae derived by this paper.
High Strength Steel in Buildings and Civil Engineering Structures: Design of Connections
Authors: Coelho Ana M. Girão , Bijlaard Frans
Published: August 2010

There is an increasing demand for high strength steel in the construction of buildings and civil engineering structures. However, there is a significant lack of knowledge of the behaviour of this type of construction. Research must focuses on the characterization of the strength and ductility of members (tension, compression and flexural members) and joints. In view of the severe deformation demands that are placed on many type of joints, particularly bolted connections, a special emphasis is given to assess current joint design criteria to understand what is expected of the high strength steel material. To address these topics, an experimental investigation was undertaken on moment connections with end plates made from high strength steel S460, S690 and S960 (yield stress of 460 N/mm2, 690 N/mm2 and 960 N/mm2, respectively) to provide insight into the nonlinear behaviour of this joint type. Test results show that the extrapolation of current design philosophy based on the semi-continuous/partially-restrained concept gives accurate strength predictions and that these connections can achieve reasonable rotation demands.
Experimental Study on Fire-Exposed Rectangular Concrete-Filled Steel Tubular (CFST) Columns Subjected to Bi-Axial Force and Bending
Authors: Jiang Shao-Fei , Wu Zhao-Qi , Niu De-Sheng
Published: August 2010

This paper provides new test data and changing regularity of behavior of rectangular concrete-filled steel tubular columns that have been exposed to high temperature and subsequently are subjected to bi-axial force and bending. Fourteen specimens exposed to constant high temperatures were tested to investigate the residual behavior of them. The investigation emphasized the effect of experimental parameters, such as temperature, slenderness ratio, eccentric angle, height-to-width ratio and confining coefficient, on residual bearing capacity and ductility of members. It is found that the bearing capacity and ductility are mainly influenced by the testing parameters. After being heated to a high temperature lower than 600 °C, the columns still have good carrying capacity. The ductility coefficients of all the specimens in the test are not less than 5.6, which indicates that CFST columns subjected to bi-axial compression and bending have good ductility even after high temperature exposure. The experimental results provide the foundation for assessing, repairing and strengthening the fire-damaged structures.
Investigations on Flexural Strength and Stiffness of Hollow Slabs
Authors: Chung Lan , Lee Sang-Hyun , Cho Seung-Ho , Woo Sung-Sik , Choi Kyoung-Kyu
Published: August 2010

A new type of hollow slab making use of plastic air balls has been developed, which can effectively reduce the amount of concrete and self weight of concrete structures. In this study, flexural and free vibration tests were carried out to investigate flexural behaviour, including the flexural stiffness, cracking, strength, and ductility. Six test specimens were examined: two conventional RC slabs; two hollow slabs; and two partially precast concrete slabs. The test parameters also included two different types of plastic balls. The test results showed that the hollow slabs yield a satisfactory flexural behaviour (i.e., crack pattern, and flexural strength) which is similar to that of conventional concrete solid slabs up to the ultimate state. It was also found that the current design provisions for concrete solid slabs are applicable to hollow slabs, without significant modification, for the evaluation of flexural strength and initial stiffness essential to the serviceability check.
Design Force Estimation Using Artificial Neural Network for Groups of Four Cylindrical Silos
Authors: Yuksel S. Bahadir , Arslan M. Hakan
Published: August 2010

The computation of design forces for the reinforced concrete groups of four cylindrical silos (GFCS) is fairly difficult because of the continuity of the walls between the adjacent silos. In this study, the efficiency of the artificial neural network (ANN) in predicting the design forces and the design moments of the GFCS due to interstice and internal loadings was investigated. Previously obtained finite element (FE) analyses results in the literature were used to train and test the ANN models. Each parameter (silo wall thickness, intersection wall thickness and the central angle spanning the intersection walls of the GFCS) affecting design forces and moments was set to be an input vector. The outputs of the ANN models would be the bending moments, hoop forces and shear forces at the supports and crowns of the interstice walls due to interstice loadings; the maximum axial forces and maximum bending moments at the external walls due to internal loadings. All the outputs of the ANN models were trained and tested by three-layered 11 back-propagation methods widely used in the literature. The obtained results presented that these 11 different methods were capable of predicting the design forces and the design moments at the interstice and external walls of the GFCS used in the training and testing phases of the study.
Extensions and limitations of analytical airfoil broadband noise models
Authors: Roger Michel , Moreau Stéphane
Published: August 2010

The present paper is a state-of-the-art of a special class of analytical models to predict the broadband noise generated by thin airfoils in a flow, either clean or disturbed. Three generating mechanisms are addressed, namely the noise from the impingement of upstream turbulence called turbulence-interaction noise, the noise due to the scattering of boundary-layer turbulence as sound at the trailing edge for an attached flow called trailing-edge noise, and the noise generated due to the formation of a coherent vortex shedding in the near wake of a thick trailing edge, called vortex-shedding noise. Different analytical models previously proposed for each mechanism are reviewed, as declinations of the same basic approach inherited from the pioneer work performed by Amiet in the seventies and based on an extensive use of Schwarzschild's technique. This choice is only an alternative to other models available in the literature and is made here for the sake of a unified approach. Issues dealing with the input data and related to the practical applications to fan noise predictions are rapidly outlined. The validity of the models is ckeched against dedicated experiments with thin airfoils and the limitations as the real configurations depart from the model assumptions are pointed out.
Geoffrey M. Lilley: A Very Brief Biography
Authors: Morris Philip J.
Published: August 2010

This introductory article is an attempt to highlight some background information as well as some career highlights for Professor Geoffrey M. Lilley. Though an attempt has been made to describe some earlier activities, there is an emphasis on those achievements made after I crossed paths with Professor Lilley in 1964. In the next article in this special issue Bob Westley gives a much lengthier description of his collaborations with Professor Lilley at Cranfield College of Aeronautics in the 1940's and 50's. It must be left to others, including Professor Lilley himself, to expand on the brief biography and bibliography compiled here. I have kept the account very factual and that may make it somewhat dry reading, though the breadth of Professor Lilley's achievements may come as a surprise to some. It did to me. If I had chosen to include my recollections of Professor Lilley's many stories of his adventures around the world, this article would have been much much longer. Also, I could never do these stories justice, as Professor Lilley's skill as a raconteur is unrivalled. I hope that this article will give the reader some sense of Professor Lilley's contributions to aerospace engineering and science for more than seven decades.
Plasma Actuators for Noise Control
Authors: Huang Xun , Zhang Xin
Published: August 2010

In this article the use of plasma actuation for noise control is reviewed. This research follows the tradition of Geoffrey Lilley who conducted the first experiment relevant to aircraft noise, controlling jet noise by disrupting the helical mode of noise radiation. Advances in electronics, control theory, manufacture process, and diagnostic tools now allow more sophisticated control methods to be developed. In addition to propulsive system noise, airframe noise has now become equally important in defining the overall aircraft noise. Plasma actuation represents a novel method to control aircraft noise, worthy of research and development. Advantages of the approach include simplicity, absence of mechanical moving parts, and fast response. Cases studied in this article demonstrated that the method can be used to attenuate both tonal and more importantly broadband noise radiated by typical aircraft components. The limits and constraints of the methods are also discussed.
Porous Airfoils: Noise Reduction and Boundary Layer Effects
Authors: Geyer Thomas , Sarradj Ennes , Fritzsche Christoph
Published: August 2010

The present paper describes acoustic and hot–wire measurements that were done in the aeroacoustic wind tunnel at the Brandenburg University of Technology Cottbus on various SD7003–type airfoils made of different porous (flow permeable) materials. The objective of the research is the analysis of the turbulent boundary layer properties of porous airfoils and, subsequently, of the noise generated at the trailing edge. The influence of the porous materials, characterized by their air flow resistivity, is discussed. The acoustic measurements were performed using a planar 56–channel microphone array and the boundary layer properties were measured using constant temperature anemometry. The recorded acoustic data underwent further processing by application of advanced beamforming algorithms. A noticeable reduction of the emitted trailing edge noise was measured for the porous airfoils over a large range of frequencies. At high frequencies, some of the porous airfoils were found to generate more noise than the reference airfoil which might be due to the surface roughness noise contribution. It is found that the turbulent boundary layer thickness and the boundary layer displacement thickness of the airfoils increase with decreasing flow resistivities for both suction and pressure side. Both boundary layer thickness and displacement thickness of the porous airfoils are greater than those of a non-porous reference airfoil
Shift+Design: Scripts and other Design Artifacts
Authors: Llach Daniel Cardoso
Published: August 2010

Beyond the debate about the possible advantages of the automation of time-consuming drafting tasks, or of the expressive qualities that emerge from the use of scripts in architectural design, this article posits the idea that scripts constitute a new kind of “design artifact”, reconfiguring a designer's engagement with a design problem. By examining how scripts destabilize dominant conceptions of architectural representations as figural descriptions the article delineates the ongoing emergence of a performative and computational epistemology of architectural design.
Designing for Constant Change: An Adaptable Growth Model for Architecture
Authors: Narahara Taro
Published: August 2010

Design of universal components that can tolerate technological, environmental, and circumstantial changes over time is a challenge for an architect. In this paper, I would like to propose a scaled prototype of architectural components that can reconfigure themselves into globally functional configurations based on feedback from locally distributed intelligence embedded inside the component. The project aims at demonstrating a design system that can respond to dynamically changing environment over time without imposing a static blueprint of the structure in a top-down manner from the outset of design processes. The control of the subunits are governed by the logic of a distributed system simulated by the use of multiple microcontrollers, and appropriate geometrical configurations will be computationally derived based on physical-environmental criteria such as solar radiation from various sensors and social-programmatic issues.
Non-Linear Architectural Design Process
Authors: Grobman Yasha Jacob , Yezioro Abraham , Capeluto Isaac Guedi
Published: August 2010

The introduction of the computer to the architectural design process have facilitated the possibility to examine a large number of design alternatives by allowing continuous variation between pre defined constraints. However, for the most part, evaluation and comparison of the alternatives is still handled manually in a linear fashion by the designer.

This paper introduces a different approach to the architectural design process, which calls for a multithreaded or a non-linear design process. In a non-linear design process design directions and alternatives are generated, presented and evaluated simultaneously, and in real time. As an example for a non-linear design process the Generative Performance Oriented Design model and software tool (GenPOD) are presented and discussed.

Moving towards non-linear modes of design arguably increases design creativity by allowing generating and evaluating a greater number and variation of design alternatives.
What Can Coach Education Programmes Learn from the Teachers? Model-Based Instruction in a UK National Governing Body Award Course
Authors: Roberts Simon
Published: August 2010

The purpose of this article is to examine the role and nature of Model Based Instruction (MBI) and discuss how Instructional Models (IM) such as Tactical Games Concepts (TGC) and Sport Education (SE) have become embedded in the pedagogic delivery of a coach education programme for one particular sports governing body, the England and Wales Cricket Board (ECB). This article will discuss how learning ‘how to coach’ principles have elements of MBI and reaffirm the view current coach education discourse and physical education discourse actually contain more similarities than differences. It is recommended that coach education teams engage in greater collaboration with experienced teachers of physical education as well as academics in higher education institutes (HEI's) recognised for their expertise in MBI.
QoS Specification in Software Architecture for QoS-aware Applications
Authors: Zhou Xiaocong , Li Peiyan
Published: August 2010

QoS-aware applications have become urgently demanded especially in service oriented computing environment. Specifying software architectures of QoS-aware applications is not a trivial task because such architectures are complex and dynamic, evolving at runtime according to QoS values and changes. To specify architectures of QoS-aware applications requires to solve two problems i.e. how to specify QoS in the architectures and how to specify the dynamism of the architectures. The dynamism of the architectures can be modelled with primitive actions of Archware π-ADL. In this paper, through the definition of QoS enhanced architecture styles, π-ADL is extended with QoS specifications to facilitate the architecture modelling of QoS-aware applications, in which QoS specifications are handled as first class entities. The QoS-based architectural mismatch check is developed to detect some QoS violations at the stage of architecture design. A case study is given to illustrate how to describe QoS-aware architectures and how to do the QoS-based architectural mismatch check.
Determination and Scaling of Thermo Acoustic Characteristics of Premixed Flames
Authors: Alemela P. R. , Fanaca D. , Hirsch C. , Sattelmayer T. , Schuermans B.
Published: August 2010

The paper investigates the determination and the scaling of thermo acoustical characteristics of lean premixed flames as used in gas turbine combustion systems. In the first part, alternative methods to characterize experimentally the flame dynamics are outlined and are compared on the example of a scaled model of an industrial gas turbine burner. Transfer matrix results from the most general direct method are contrasted with data obtained from the hybrid method, which is based on Rankine-Hugoniot relations and the experimental flame transfer function obtained from OH*-chemiluminescence measurements. Also the new network model based regression method is assessed, which is based on a n – τ – σ dynamic flame model. The results indicate very good consistency between the three techniques, providing a global check of the methods/tools used for analyzing the thermo acoustic mechanisms of flames. In the second part, scaling rules are developed that allow to calculate the dynamic flame characteristics at different operation points. Towards this a geometric flame length model is formulated. Together with the other operational data of the flame it provides the dynamic flame model parameters at these points. The comparison between the measured and modeled flame lengths as well as the n – τ – σ parameters shows an excellent agreement.
A Study on the Kelvin-Helmholtz Instability Using Two Different Computational Fluid Dynamics Methods
Authors: Atmakidis Theodoros , Kenig Eugeny Y.
Published: August 2010

The two-dimensional Kelvin-Helmholtz instability which arises in two immiscible co-currently moving horizontal liquid layers is studied numerically. Two different methods for capturing the free interface movement are applied, namely the volume-of-fluid method and the level-set method. Both methods are very popular and available within commercial computational fluid dynamics tools. The wave is initialized using two different perturbations implemented into the model. As a case study, a system comprising a toluene layer and an aqueous layer is chosen. Numerical results obtained by both methods are in a good agreement with the linear stability theory for small wave amplitudes. The application of both methods is compared and their advantages and drawbacks are highlighted.
Interface Tracking Simulation of Drops Rising through Liquids in a Vertical Pipe Using Three Coordinate Systems
Authors: Hayashi Kosuke , Kurimoto Ryo , Tomiyama Akio
Published: August 2010

Interface tracking simulations of single drops rising through a vertical pipe are carried out using three coordinate systems, i.e. cylindrical, general curvilinear and Cartesian coordinates, to investigate the effects of coordinate system and spatial resolution on the accuracy of predictions. Experiments of single drops in a vertical pipe are also conducted to obtain experimental data for comparisons with simulations. The drop shape observed are spheroidal and deformed spheroidal at low values of the diameter ratio, Λ, of the sphere-volume equivalent diameter of a drop to the pipe diameter, whereas they take bullet-shapes at large Λ. The conclusions obtained are as follows: (1) the effects of coordinate system on drop shape are small at low Λ. At large Λ, the effects are also small for drops in a low viscosity system, whereas non-physical shape distortion takes place when the Cartesian coordinates are used with low spatial resolution for drops in a high viscosity system, and (2) the drop terminal velocity and the velocity profile in the liquid film between a bullet-shaped drop and a pipe wall are well predicted using all the coordinate systems tested even at low spatial resolution.
Morphodynamics of Wadden Sea Areas – Field Measurements and Modeling
Authors: Albers Thorsten , von Lieberman Nicole
Published: August 2010

The Wadden Sea areas of the German North Sea coast are affected by intense morphodynamics. Especially in the mouths of the estuaries sedimentation and erosion occur on different temporal and spatial scales and therefore challenge the decision-makers. To satisfy the requirements, which modern maritime traffic demands, a sustainable concept for sediment management has to be developed to grant an economic and ecologic balanced system. To evaluate different actions and their effects, e.g. by means of numerical models, an improved knowledge of morphodynamic processes on tidal flats is required. The Institute of River and Coastal Engineering at the Hamburg University of Technology runs detailed measurements to collect hydrodynamic and morphodynamic data of tidal flats in the estuary Elbe, that is the approach to the port of Hamburg. Water levels, flow and wave parameters and concentrations of suspended sediments are recorded in high resolution. Furthermore, the bathymetry is determined in frequent intervals with a multi-beam echo sounder.
A New Approach in the Design of High‐Risk Infusion Technology
Authors: Murphy Robert , Wilcox Steven
Published: August 2010

The syringe infusion pump has been established as the instrument of choice for high‐risk infusions, where potent drugs are often delivered at low rates of flow. However, numerous instances of unexpected flow error with consequent patient physiological impact have been reported. These include unwanted bolus delivery on release of line occlusion, dosage fluctuation due to pump height change and fluid reflux within the multiple pump installations now common in the Intensive Care Unit (ICU). This article examines the performance of a typical ICU syringe infusion pump and identifies mechanical compliance, inherent in commercial designs, as a source of flow error that should not be ignored by equipment designers. A prototype low compliance system is described and tested with performance compared to the conventional design, demonstrating advantages in terms of lower flow error.
Selective Inactivation of Viruses with Femtosecond Laser Pulses and its Potential Use for in Vitro Therapy
Authors: Tsen Shaw-Wei D. , Tsen Yu-Shan D. , Tsen K. T. , Wu T. C.
Published: August 2010

Introduction: Traditional biochemical and pharmaceutical methods employed today encounter problems of clinical side effects and drug resistance, and their use is becoming limited. Therefore, it has become important and necessary to develop new, alternative strategies to combat viral diseases.

Materials and Method: A variety of viruses including M13 bacetriophage (nonenveloped ssDNA), tobacco mosaic virus (nonenveloped ssRNA), human papillomavirus (nonenveloped dsDNA) and human immunodeficiency virus (enveloped ssRNA), together with human red blood cells, Jurkat T‐cells and mouse dendritic cells in their buffer solutions have been irradiated with near‐infrared subpicosecond laser pulses in vitro.

Results: A window of laser power density, approximately between 1 GW/cm2 and 10 GW/cm2, has been observed that allows killing the viral particles while leaving mammalian cells unharmed.

Conclusion: The ultrashort pulsed laser technology may have great potential for disinfection of blood components.
Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities
Authors: Bonnema Eric , Pless Shanti , Doebber Ian
Published: August 2010

The Advanced Energy Design Guide for Small Hospitals and Healthcare Facilities (AEDG‐SHC) was recently completed. It is the sixth document in a series of guides designed to achieve 30% savings over the minimum code requirements of ANSI/ASHRAE/IESNA Standard 90.1‐1999. The guide [1] is available for print purchase or as a free download from http://www.ashrae.org/aedg and provides user‐friendly assistance and recommendations for the building design, construction, and owner communities to achieve energy savings. Included in the guide are prescriptive recommendations for quality assurance and commissioning; design of the building envelope; fenestration; lighting systems (including electric lighting and daylighting); heating, ventilation, and air‐conditioning (HVAC) systems; building automation and controls; outside air (OA) treatment; and service water heating (SWH). The guide educates, provides practical recommendations for exceeding code minimums, and provides leadership to help design teams and owners produce higher efficiency commercial buildings.
Numerical Analysis of Lateral Inertial Confinement Effects on Impact Test of Concrete Compressive Material Properties
Authors: Hao Yifei , Hao Hong , Li Zhong-Xian
Published: August 2010

Dynamic material properties, in particular the dynamic strength, of concrete material are usually obtained by conducting laboratory tests such as drop-weight test and Split Hopkinson Pressure Bar (SHPB) test. It is commonly agreed that a few parameters associated with stress wave propagation will affect the test results, including the lateral and axial inertial effect, end friction confinement and stress wave reflection and refraction. Many different measures have been proposed to eliminate or limit the influences of these effects in dynamic tests of material properties. However, owing to the nature of dynamic loadings, especially those with high loading rates, it is very unlikely to completely eliminate these influences in physical testing. Moreover, it is also very difficult to quantify these influences from the laboratory testing data. In the present study, a refined mesoscale concrete material model is developed to simulate impact tests and to study the influences of lateral inertial confinement on concrete compressive strength increment at high strain rate. The commercial software AUTODYN is used to perform the numerical simulations. Numerical simulations of concrete specimens of different dimensions and under impact loads of different loading rates are carried out. The results are compared with those obtained from laboratory tests, with those specified in the code and simulated with homogeneous concrete material model. The reliability of the numerical simulation of impact tests is verified. It is found that the influences of lateral inertial confinement effect on Dynamic Increase Factor (DIF) is strain rate and specimen size dependent. Neglecting aggregates in concrete specimen in laboratory tests and numerical simulations lead to underestimation of DIF of concrete material.
Analysis of Dynamic Response of Concrete Using a Mesoscale Model Incorporating 3D Effects
Authors: Lu Yong , Song Zhenhuan , Tu Zhenguo
Published: August 2010

Shock and impact loading often generates stress waves in the responding structural object with a drastic time and spatial variation. Consequently the transient response of the material involves not only high strain rate, but also a highly non-homogeneous stress field with respect to the mesoscale heterogeneity of the concrete-like materials. To comprehensively capture the material response and the underlying mechanisms under such loading conditions, the use of a mesoscale model is desirable. This paper discusses the development of a mesoscale model that describes reasonably the random mesoscopic structure of concrete materials and at the same time allows for the simulation of response under complex dynamic loads. Due to the complexity in the generation and meshing of the random aggregate structure of concrete, at the present stage the random mesoscale geometry is generated within a 2D plane. The use of a 2D representation of a concrete is common and may be acceptable in lower loading rate applications, however, under high rate loading a 2D model for concrete in compression could introduce noticeable errors due to an inability to fully capture the crucial lateral inertia confining effect. This special phenomenon is investigated in this paper, and a remedial modelling scheme is proposed to minimize the inaccuracy in a 2D mesoscale model for high strain rate loading. Finally, the experimentally observed strain rate increase factor is discussed in light of the mesoscale numerical modeling results.
Contact Explosion Resistance of Concrete Plates Externally Strengthened with FRP Laminates
Authors: Beppu Masuhiro , Ohno Tomonori , Ohkubo Kazunori , Li Bing , Satoh Kazuyuki
Published: August 2010

The present work is intended to evaluate the effectiveness of fiber sheet reinforcement on explosive-resistant performance of concrete plates. Carbon fiber sheets or aramid fiber sheets have been employed to reinforce concrete plates. Explosion tests have been conducted to examine the effect of fiber sheet reinforcement on local damage and fragmentation of concrete plates. Test data are compared with the estimated values formulated by Morishita et al. and the characteristics of local damage are discussed. Local damage of concrete plates reinforced by carbon or aramid fiber sheets has been extremely reduced as compared with that of concrete plates without fiber sheet reinforcement. These fiber sheets also have prevented concrete plates from fragmentation.
The Development of Zr-2.5Nb Pressure Tubes for CANDU Reactors
Authors: Cheadle B. A.
Published: August 2010

The first reactor to use zirconium alloy tubes to contain hot pressurized water as a heat transport medium was the Hanford N reactor in 1962. For this reactor, three companies that had suitable extrusion and cold working equipment were given contracts to produce Zircaloy-2 tubes. All the companies were successful, and tubes from each company were installed in the reactor. When Canada decided to design and build a power reactor (nuclear power demonstration (NPD)), it elected to use the pressure tube concept and gave a contract to one of the companies (Chase Brass) to fabricate the Zircaloy-2 tubes. Douglas Point and Pickering Units 1 and 2 followed NPD, and all used similar Zircaloy-2 pressure tubes. A stronger tube was desired in order to thin the wall and improve the neutron economy. An alloy development program in the USSR had shown that the alloy Zr-2.5Nb looked very promising as a stronger alloy than Zircaloy-2, and both the USSR and Canada developed this alloy and subsequently used Zr-2.5Nb pressure tubes in their reactors. When both the Zircaloy-2 and Zr-2.5Nb pressure tubes were first installed in the reactors, several important properties and characteristics such as hydrogen ingress into the metal from corrosion in water, the enhancement of creep by neutron irradiation, shape change by neutron irradiation, reduction in fracture toughness by neutron irradiation, and delayed hydride cracking were not appreciated. These properties all led to problems during the service lives of the early tubes. Large research programs investigated these properties and showed that the α-grain size, shape, and crystallographic texture, the distribution of the β-phase, the dislocation type, and density as well as the micro-chemistry controlled the in-reactor properties of the tubes. This information enabled the design and operation of the reactors to be changed so that the tubes had satisfactory service lives. In addition, the information was used to fabricate tubes that had much improved properties and service lives.
The difficult patient: drug interaction and the influence of concomitant diseases on the treatment of hypothyroidism
Authors: Ward Laura S.
Published: August 2010

Although most hypothyroid patients do well with one single tablet of thyroxine daily, approximately 10% are dissatisfied and another important group of patients is difficult to control. We reviewed the most common causes for frequent-dose adjustment or high-dose requirement, including poor compliance with therapy and inadequate medication. Since these two causes have been ruled out, drug interaction and other concomitant diseases need to be investigated. Requirements of thyroxine increase in all conditions characterized by impaired gastric acid secretion. Proton-pump inhibitors, antacids and a long list of drugs may decrease thyroxine absorption. In addition, a series of diseases including celiac disease and chronic inflammatory intestinal diseases, as well as nutritional habits may be important in patient control. Finally, we mention the effects of a growing list of drugs and thyroid disruptors that may also affect thyroid hormone metabolism at many levels.