bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling Intelligent Electronic Consumer Products
Authors: Thorpe Christopher C. , Friend Clifford M.
Published: August 2002

This paper is based upon an ongoing research programme which aims to investigate the issues related to the use of intelligent materials within electronic consumer products, specifically those used in the domestic environment. The paper discusses the opportunities which exist for the use of intelligent materials in electronic consumer products, and explores the problems faced by the designer in the development of such products. The paper focuses on the issues surrounding the nature of user object interaction within new product development and examines the need for a more integrated approach to user requirements and concept development. A case study is used to illustrate how computer modelling of intelligent consumer product concepts can greatly assist in the design and development process.
A Simple Failure Analysis of the Composite Transmission Tower
Authors: Yeh Hsien-Yang , Yeh Hsien-Liang
Published: August 2002

The failure analysis of the composite transmission tower made of new and better material, E-Glass with vinylester, is presented in this paper. The conventional fastener method to join the cross members to the leg members was in place of a slip joint that was developed by Goldsworthy Engineering.

The lamina of the leg member and the cross bracing were tested and compared with several other failure criteria, including the Tsai-Wu Theory, the Tsai-Hill Theory, the Hoffman Theory, the Fischer Criterion, the Cowin Criterion, the Yeh-Stratton Criterion, and the Quadric Surfaces Criterion. Besides, the full-scale tower tests were performed at Electrical and Power Research Institute.

From the results of the simple failure analysis of the composite transmission tower with those failure criteria, it shows that building a transmission tower from a composite material, E-Glass and vinylester, is feasible.
A Numerical Study of Effect of Natural Convection on Thermal Properties of Horizontal Oriented Porous Insulation
Authors: Shankar V. , Hagentoft C. E.
Published: August 2002

This paper deals with numerical computations carried out to predict the effect of natural convection on the thermal performance of porous material. The effect of natural convection in a horizontal porous layer on heat transfer will be discussed. The study of this configuration is essential to understanding the performance of insulation of the type commonly used in roofs and attics. The influence of natural convection on the global heat transfer rate for mineral wool, loose-fill and insulation made of small and large polystyrene balls was studied. The results are presented in terms of dimensionless Nusselt and Rayleigh numbers as a function of temperature difference across the insulation. The temperature distribution across the insulation are also plotted.
Optimal Design and Experimental Validation of Compliant Mechanical Amplifiers for Piezoceramic Stack Actuators
Authors: Frecker Mary , Canfield Shawn
Published: August 2002

An optimization method has been developed for design of compliant mechanical amplifiers for piezoceramic stack actuators. A topology optimization approach is used where the objective is to maximize the stroke amplification, and results show good algorithm convergence and good mechanism performance. The focus of this paper is on using the optimal topology solution to generate a solid model, and on improving the actuator performance through detail design and analysis of the resulting monolithic compliant mechanical amplifiers. A study of the effect of various flexure hinge configurations and other design parameters on the amplification and mechanical advantage of an actuator is performed. Another actuator with a large stroke amplification is designed using a batch of random starting points to the optimization algorithm. Prototype actuators have been fabricated, and the results of experimental validations are presented.
Maximal Modal Force Rule for Optimal Placement of Point Piezoelectric Actuators for Plates
Authors: Bin Li , Yugang Li , Xuegang Yin , Shanglian Huang
Published: August 2002

Optimal placement of actuators on intelligent structures is an important part of intelligent structure designs. The optimal collocation of actuators includes placement collocation and number collocation. It decides stability, controllability and control efficiency of structural control systems. With the development of control technology, the optimal collocation of actuators in structures is more and more important. Although optimal collocation of actuators can be determined by experience in some cases, experience is useless for complicated structures. So optimal collocation of actuators must be realized by optimal theory. Based on modal control theory, the Maximal Modal Force Rule is put forward for intelligent flexible plates bonded point piezoelectric actuators on their surface in this paper. The rule points out that point piezoelectric actuators should be bonded on the places of maximal modal strains of every order mode to produce maximal modal control forces. The formulae for independent modal space control and coupling modal space control are derived. The results of computer emulating of a plate show that the rule is right and effective.
A Theoretical Examination of the Possibility of Spontaneous Combustion of Laundry in Tumble Dryers Part 2: The Role of Reactive Contaminants
Authors: Jones J. C.
Published: August 2002

Hot spot theory is applied to the contents of a laundry tumble dryer in order to predict how far above the dryer temperature an item previously rendered “hot” by reason of oil or solvent contamination would need to be in order to cause ignition of the dryer contents.
Effect of Water Content on the Thermal Inactivation Kinetics of Horseradish Peroxidase Freeze-Dried from Alkaline pH
Authors: Lemos M. A. , Oliveira J. C. , Saraiva J. A.
Published: August 2002

The thermal inactivation of horseradish peroxidase freeze-dried from solutions of different pH (8, 10 and 11.5, measured at 25 C) and equilibrated to different water contents was studied in the temperature range from 110 to 150 C. The water contents studied (0.0, 1.4, 16.2 and 25.6 g water per 100 g of dry enzyme) corresponded to water activities of 0.0, 0.11, 0.76 and 0.88 at 4 C. The kinetics were well described by a double exponential model. The enzyme was generally more stable the lower the pH of the original solution, and for all pH values, the maximum stability was obtained at 1.4 g water/100 g dry enzyme. Values of z were generally independent of water content and of the pH of the original solution, and in the range of 15–25 °C, usually found in neutral conditions, with the exception of the enzyme freeze dried from pH 11.5 and equilibrated with phosphorus pentoxide, where a z-value of the stable fraction close to 10 C was found.
Using Polymer Characterization Techniques to Predict LDPE Resin Suitability for Extruded Foam Applications
Authors: Auger Jim , Nguyen Lan
Published: August 2002

All LDPE resins are not created equal. It is well known that autoclave LDPEs are considered to be the products of choice for extrusion coating applications. On the other hand, LDPE resins produced using tubular reactors have a different structure that makes them more suitable for extruded foam applications. More specifically, within the choices of tubular LDPE resins for extruded foam applications, some are easier to process and produce better quality foam products than others. What makes one resin better than another?

This paper discusses the general chemical and rheological differences between autoclave and tubular LDPE resins then focuses in more detail on those differences for a variety of tubular LDPE products used in the extruded foam market.
Domain-Wall Motion under Mechanical Stresses and Giant Piezoresistivity in Thin Barium Titanate Ceramic Bars
Authors: Kuwabara Makoto , Hamamoto Kouichi
Published: August 2002

Extremely large piezoresistance (stress-sensitive resistance), equivalent to a value of the gage factor (the magnitude of resistance change per strain) of > 107 was observed in single grain boundaries formed in thin semiconducting barium titanate ceramic bars at room temperature. The samples were produced to have a grain structure consisting of single grains joined together in series and a diameter in the range 10-20,um. In this study, observation of ferroelectric domain structures and measurements of resistance were simultaneously carried out for some samples under cyclic mechanical stresses to closer look at the influence of the morphological change of ferroelectric domain structures on the grain boundary resistance in the materials. In a bar sample with a single grain boundary, a 90° domain wall was observed to appear and move from one end of the sample to the other during one cycle of the stress applied. It has been found that the observed large piezoresistance is closely connected with a drastic change of the domain structure in the vicinity of grain boundaries in the samples.
Imaging Techniques for Gene Therapy: SPECT, PET, and MRI
Authors: Haberkorn Uwe , Altmann Annette
Published: August 2002

Gene therapy by the transfer and expression of suicide genes is performed using genes coding for nonmammalian enzymes that transform nontoxic prodrugs into toxic metabolites. Employing radiolabeled specific substrates and scintigraphic procedures to determine the functional activity of the recombinant enzyme in vivo, a therapeutic window of maximal gene expression and consecutive drug administration may be defined. If the gene therapy approach is based on the transduction of receptor genes, the recombinant gene expression in tumor cells can be monitored with radiolabeled ligands. Transfer of transporter genes as the sodium iodide transporter may also lead to the visualization of transduction via accumulation of iodide or pertechnetate. Furthermore, imaging based on transchelation of oxotechnetate to a polypeptide motif from a biocompatible complex with a higher dissociation constant than that of a diglycilcysteine complex or tyrosinase gene transfer for metal ion scavenging have been described. In addition, therapy effects may be assessed by the evaluation of the morphological changes of the tumor using magnetic resonance imaging or, more effectively, by the measurement of changes in metabolism with positron emission tomography employing tracers of tumor metabolism and proliferation. Finally, enzyme or receptor genes may serve as noninvasive reporter genes, if applied in the context of bicistronic vectors leading to coexpression of the therapeutic gene and the noninvasive reporter gene.
Computationally Efficient Fracture Analysis of Electronic Packages through Decomposition
Authors: Natekar Devendra , Subbarayan Ganesh
Published: August 2002

In the present paper we describe and demonstrate a computationally efficient technique for analyzing fracture mechanics problems in mixed linear-nonlinear systems. The technique combines the methodology of Rybicki and Kanninen for calculation of the energy release rate in fracture processes with a decomposition based analysis procedure recently proposed by Subbarayan and co-workers. The methodology will enable quick design decisions during the package development stages without significant loss of accuracy. The developed procedure is demonstrated on a hypothetical 5 × 5 array package. It is shown that on this representative package nearly 30% time savings (or a 150% speed-up) can be acheived in estimating the energy release rate at an accuracy loss of only 6.2%. Prior research has shown that the analysis time is nearly independent of package size, indicating unbounded speed-ups for larger package sizes.
The Polyurethane-Drug Composites: Synthesis, Properties and a Kinetic Model
Authors: Grigorieva Maya , Gladir Irina , Galatenko Natalia
Published: August 2002

Oligoglycol-based polyurethane composites were synthesized and filled with an antibiotic—cephasoline. Using mechanical testing as well as IR-spectroscopy and HPLC methods, the properties of these composites were studied as biodegradable carriers for medicinal substances. Cephasoline was found to be released at an appreciable rate from the polyurethane carriers into a physiological solution at 37°C. A catalyst (Fe tris-acetylacetonate) added to the cephasoline-polyurethane system not only helped to optimize the polymerization process but also provided for steady release of cephasoline in vitro during a long time.
An Analytical and Numerical Study to Simulate the Evolution of Dynamic Failure with Local Elastodamage Models
Authors: Xin X. , Chen Z.
Published: August 2002

Waves can propagate in a continuum only when the tangent stiffness tensor of the material is positive definite. The wave equation appears to lose its hyperbolicity with the advent of material softening. To overcome this difficulty, a partitioned-modeling approach with the use of local elastodamage models is applied to solving wave problems involving material degradation. A closed-form solution for wave propagation in a damaged bar is derived in this paper, with the use of the similarity method in the partitioned domain. The initial point of the localization is taken as the point at which the type of governing differential equation transforms from a hyperbolic one to an elliptic one due to material damage. The evolution of localization is represented by a moving material surface between the damaged domain and non-damaged domain. The motion of the material surface is of diffusion type, representing macroscopically the progressive percolation of heterogeneous microdamage. Based on the analytical solution, a numerical procedure is then proposed for the partitioned-modeling approach. The fast convergence of the proposed numerical procedure is shown by comparing the numerical solutions with the analytical ones. The numerical procedure is then applied to the simulation of failure wave with the use of a local damage model. It is shown that the evolution of dynamic localization can be simulated without invoking higher order terms if a moving material surface of discontinuity is introduced.
A Unified Micromechanical Model for the Mechanical Properties of Two Constituent Composite Materials. Part III: Strength Behavior
Authors: Huang Zheng Ming
Published: August 2002

This series of papers reports a new, general, and unified micromechanical model for estimating the three-dimensional mechanical properties of a composite made from two constituent materials, i.e., continuous fiber and matrix. The linear elastic and elasto-plastic behaviors have been studied in Parts I and II respectively. The present paper investigates the tensile strength and failure mode of the composite. The tensile strength of the composite is predicted based on the ultimate stresses in the constituent phases, as the states of stresses in both phases are explicitly represented as the function of the applied overall stress field. The maximum normal stress theory for isotropic materials is incorporated with this prediction. As long as the maximum normal stress in either the fibers or the matrix attains its ultimate value, the composite is considered to fail, and the corresponding strength and failure mode are thus automatically defined. This makes determination of the composite strength as well as the failure mode extremely general, yet particularly easy. The composite can be subjected to any kind of load combination, whereas the corresponding strength behavior is determined through the same simple procedure. Comparisons between predicted and measured tensile strengths for several unidirectional composites under off-axial loads and for a plain weft-knitted fabric-reinforced composite under different uniaxial loads confirm that the present micromechanical strength theory is very efficient.
Simulations and Experiments on Low-Pressure Permeation of Fabrics: Part II—The Variable Gap Model and Prediction of Permeability
Authors: Senoguz M. T. , Dungan F. D. , Sastry A. M. , Klamo J. T.
Published: August 2002

Use of the creeping flow assumption provides a computationally efficient and accurate means of predicting flow fronts in reinforcement media in many technologically important polymer processes. In the case of fabrics, this creeping flow is shown to proceed primarily through the gaps in fabrics, with capillarity playing little if any role for commonly used materials. This finding has important implications for selection of strategy in modeling manufacturing processes of such materials. Namely, in the presence of fabric deformation which induces local shear, changes in the gap architecture greatly affect the flow patterns, and are not well predicted by tensor transformation of Darcy-type permeabilities. Asimple, classic flow model is adapted to the case of fabrics penetrated by low-pressure viscous liquids after careful analysis of fabric architecture. An applicability range of this creeping flow model, the variable gap model, is developed. The present paper gives the model assumptions, and confirmation of its agreement with more sophisticated calculations. A demonstration of the approach for an unbalanced fabric (Knytex 24 5×4 unbalanced plain-woven glass fabric) shows excellent prediction of the bounds on flow behavior, and supports our earlier experimental findings on flow front orientation. This approach also shows clear superiority to semi-empirical, geometry-based models, since no fitting parameters at all are used in the modeling: only the constituent materials’ geometry and properties are needed. This methodology is better able to predict trends in flow fronts, both qualitatively and quantitatively, than semi-empirical fitting. Extension of this work to realistic production processes is planned. 1Author to whom correspondence should be addressed. 1285 Journal ofCOMPOSITE MATERIALS, Vol. 35, No. 14/2001
Reinforcement of Recycled Polyethylene with Wood Fibers Heat Treated
Authors: Robin J. J. , Breton Y.
Published: August 2002

Composite materials have been prepared using HDPE coming from wastes and spruce wood chips. These compositions with different contents in wood, exhibit improved properties when wood is preliminary heat treated in controlled atmosphere. Hence, properties such as flexural strength, resilience and adhesion between matrix and filler were mainly increased when compared to composites containing no treated wood.
Effect of Flake Distribution on Elastic Properties of Flake Composites
Authors: Li Rongzhi
Published: August 2002

Single-flake and multi-flake models of oriented flake reinforced composites have been constructed to evaluate the elastic properties of the composites. A “bundled matrix” concept was assumed to examine the effect of the flake distribution in the matrix on the longitudinal elastic modulus and Poisson’s ratio of the flake composites. The equations derived from the single-flake and multi-flake models anticipate that the longitudinal elastic properties of the oriented flake composites vary with the flake distribution in the matrix, as well as indirectly with the geometry of the flake. The longitudinal elastic modulus of the composite is predicted to be lower than that defined by the average rule of mixture for awide range of flake volume fraction exceptwhen the flake volume fraction is large enough to bundle all matrix with flake.
Influence of Color on Perception of Sweetness and Fruit Flavor of Fruit Drinks
Authors: Bayarri S. , Calvo C. , Costell E. , Durán L.
Published: August 2002

The objective of this work was to study the effects of color on the perception of both sweetness and fruit flavor of different fruit (peach, orange, kiwifruit and berries) beverages. Four samples of each fruit beverage were prepared by adding different colorants but maintaining the same composition. Color was measured using a Hunter Lab colorimeter. Samples of each of the different fruits were ranked for color, sweetness and typical fruit flavor by a group of assessors. Color was found to influence sweetness only in orange drinks but it affected intensity of typical flavor in all fruit drinks.
The Use of PET in Evaluating Tumor Response and Cancer Therapy
Authors: Lammertsma Adriaan A.
Published: August 2002

In this article, an overview is given for the use and potential of positron emission tomography (PET) in monitoring tumor response to therapy. First, the rationale for using PET to monitor response is presented. This is followed by a discussion of response monitoring using [F-18]-2-fluoro-2-deoxy-D-glucose (FDG), concentrating on the various methods that can be used to analyze the data. Thereafter, a brief summary is given of the European Organization for Research and Treatment of Cancer (EORTC) PET Study Group recommendations for standardization of data acquisition and analysis, which is needed for comparing and pooling data from different institutes. Finally, some thoughts on future directions for the use of PET in evaluating tumor response and cancer therapy are offered.
On the Flash Point of Benzoic Acid
Authors: Jones J. C.
Published: August 2002

The reported flash point of benzoic acid is examined in terms of vapour pressures and stoichiometric proportions and found to be significantly aberrant. A possible explanation is that during heating in the flash point apparatus there is decarboxylation catalysed by the metal surface.
A New Method for Determining Locations of the Piezoelectric Sensor/Actuator for Vibration Control of Intelligent Structures
Authors: Chen Suhuan , Cao Zongjie
Published: August 2002

A technique for determining the locations of piezoelectric sensors and actuators (S/As) of intelligent structures on the basis of element sensitivities of the singular-values of the controllability and observability is presented. The element sensitivity of the singular-values is used as the measure to identify the best locations of S/As, which is defined from the 1st order perturbations of singular-values of the controllability and observability. A criterion and a threshold value are used to determine which actuator/sensor elements need to be kept/removed based on the sensitivity information. Locations of S/As are determined as the point where the element sensitivity of the singular-values is the maximum. Two numerical examples, the cantilever beam and the model of solar panels, are given to illustrate the applications of the present method.
Performance-Based Assessment: Using Pre-Established Criteria and Continuous Feedback to Enhance a Student’s Ability to Perform Practice Tasks
Authors: Beck Diane E.
Published: August 2002

Performance-based assessment is a process in which pre-established performance criteria and continuous feedback are used by both the student and instructor to improve learning with an endpoint of students demonstrating their achievement of learning by performing realistic practice tasks. This manuscript describes the issues limiting widespread use of performance-based assessment, based on findings from the pharmacy, medical, and general education literature, and then proposes a model for how to successfully implement it. Performance-based assessment methods such as direct observation, the Mini-Clinical Evaluation Exercise, simulations involving standardized patients and computers, projects, presentations, learning portfolios, and the Triple Jump Exam are discussed. Successful implementation of performance-based assessment involves: 1) inculcating a culture for assessment, 2) establishing pre-specified performance criteria, 3) implementing use of the pre-established performance criteria and formative assessment methods to provide continuous feedback during the learning period, 4) using summative performance-based assessment methods, and 5) providing mechanisms for student remediation. Successful inclusion of performance-based assessment in Doctor of Pharmacy curricula should enable instructors to better prepare graduates that can provide pharmaceutical care in a quality manner.
A Hybrid Non-Contact Ultrasonic System for Sensing Bond Quality in Tow-Placed Thermoplastic Composites
Authors: Di Scalea Francesco Lanza , Green Robert E.
Published: August 2002

A novel non-contact nondestructive evaluation system is proposed for sensing bond quality in tow-placed graphite/PEEK thermoplastic composites. The inspection tool consists of a hybrid ultrasonic system which employs laser generation of narrow-band surface waves with fiberoptic light delivery, and signal detection by air-coupled transduction. The fiberoptic link enhances flexibility and remoteness of the laser source from the test piece. The system output is not influenced by the poor light reflectivity of the test graphite/PEEK material. Signal narrow-banding by light spatial modulation enhances the measurement sensitivity and avoids detrimental material ablation while allowing control of the surface wave penetration depth. The theory of the laser generation of narrow-band surface waves is reviewed and the generation efficiency as a function of the wave propagation direction in the composite is discussed.

The inspection capabilities of the proposed system are demonstrated by successful detection of a series of subsurface defects in a tow-placed unidirectional AS-4/APC-2 cylinder provided by Boeing Commercial Aircraft. The defects examined include regions of poor consolidation, inter-laminar linear porosity (voids elongated along the fibers with 1.5% volume fraction), and delamination or interlaminar weakness. The ultrasonic inspection unit is non-contact, flexible, light-weight and allows for high inspection rates. These characteristics, coupled with a large signal-to-noise ratio of the measurements, show promises for the use of the proposed sensor in on-line control of the thermoplastic tow-placement process with in situ consolidation.
Study on the Anticancer Drug 5-Fluorouracil-Conjugated Polyaspartamide Containing Hepatocyte-Targeting Group
Authors: Yan Guo-Ping , Zhuo Ren-Xi , Zheng Cong-Yi
Published: August 2002

Anticancer conjugates of 5-fluorouracil (5-Fu) and polyaspartamide, containing pyridoxamine as the hepatocyte-targeting group, were synthesized and characterized. Their sustained release properties and biodistribution were evaluated. The 5-Fu was targeted to specific organs, such as the liver, and had a sustained in vitro release rate in PBS. In vitro cytotoxicity assay showed that the polymeric drugs exhibited low cytotoxicity to the human liver cells (L-02). These polymeric drugs possess high anticancer efficiencies and induced apoptosis in the human hepatic tumor cells (Bel-7204).
Micromechanical Models for Damping in Woven Fabric-Reinforced Polymer Matrix Composites
Authors: Guan Huimin , Gibson Ronald F.
Published: August 2002

This paper describes the development of a finite element model and a closed-form model for studying viscoelastic damping in woven fabric-reinforced polymer matrix composites. The finite element model was based on the actual geometric configuration of a plain weave fabric-reinforced composite unit cell, and the damping loss factors were determined from a strain energy formulation. The closed-form model was developed by first deriving an approximate elastic solution based on the mechanics of materials theory, then applying the Elastic-Viscoelastic Correspondence Principle to the elastic solution. The damping loss factors were then determined from the viscoelastic solution. Experiments were conducted using an impulse-frequency response technique to measure damping in beam samples made of plain weave E-glass fabric-reinforced vinyl ester resin matrix composite. The predictions from both analytical models show reasonably good agreement with experimental data.
Comparison of the Thermal Decomposition Behavior of a Non-Fire Retarded and a Fire Retarded Flexible Polyurethane Foam with Phosphorus and Brominated Additives
Authors: Chao Christopher Y. H. , Wang Jing Hong
Published: August 2002

Thermogravimetric analysis was carried out to investigate the thermal decomposition behavior of a commercial fire retarded (FR) and a non-fire retarded (NFR) flexible polyurethane foam. The effects of the heating rate and the reaction atmosphere on the thermal decomposition process were studied at three different heating rates ranging from 5°C/min to 20°C/min in both nitrogen and air environment. Results from the time-of-flight secondary ion mass spectrometry (ToF SIMS) study revealed that the additives in the FR foam were phosphorus and brominated compounds. The measurements by means of colorimetric method further certified that the concentrations of phosphorus and bromine in the FR foam sample were 0.08 wt% and 1.4 wt% respectively. From the thermogravimetric (TG) and the derivative thermogravimetric (DTG) curves, it was seen that the thermal decomposition processes of both the FR and the NFR foams followed a two-step reaction in nitrogen. However, the thermal decomposition processes followed a three-step reaction in air. The thermal analysis results showed that the flame retardant additives of phosphorus and brominated compounds acted not only in the gas phase but also in the solid phase. Furthermore, the flame retardant additives decreased the thermal stability and increased the char formation in the temperature ranging from 300°C to 400°C, which, commonly, is the temperature range for smoldering combustion in this kind of foam material. From the kinetic parameters estimated from the TG and the DTG curves, it was seen that the activation energies of the flexible polyurethane foams were very sensitive to the temperature and were also influenced significantly by the flame retardant additives.
Transient Interaction of Buildings with HVAC Systems— Updating the State of the Art
Authors: Lstiburek Joseph W. , Pressnail Kim , Timusk John
Published: August 2002

This paper reviews work that has led to the development of a number of multi-zonal airflow models (network models). At present, the network analysis and perturbation methods cannot be used to solve the interstitial flow, pressure and resistance regimes. Network analysis and perturbation may suggest that such flows exist, but the complexity and workmanship dependence of the interstitial flow, pressure and resistance regime requires direct measurement. In other words, at present, the boundary conditions of the interstitial regime can be defined analytically using traditional methods, but the pressures and flows within the interstitial spaces cannot be predicted with certainty using analytical means.

Difficulties in obtaining the detailed information on mechanical systems and the leakage areas of building assemblies make the traditional approach of measuring airflows and constructing models using leakage areas impractical for diagnostic purposes. Additionally, a pressure difference across an assembly alone, where interstitial pressures are not considered, is not enough to describe performance of the building envelope. The interstitial air pressures are usually small and until recently have been beyond measurement.

Research on building envelope durability and indoor air quality has shown the significance of these small, but persisting interstitial air pressure fields. To enhance the capability of network models, a relational model was developed. This approach permits the measured building air pressure field to be used with the network analysis. Furthermore, the response of the analytical model is calibrated by comparing the effect of a specific perturbation on both the building air pressure field and the analytical model.

This paper is written in two parts, the first reviewing issues in prediction of airflow in the buildings and building envelope, the second analyzing the actual data of measured pressure response of buildings.
Review: Effect of Some Components of Milk- and Soy-Based Infant Formulas on Mineral Bioavailability
Authors: Jovaní M. , Barberá R. , Farré R.
Published: August 2002

Infants’ high nutritional needs are fulfilled by mother’s milk or infant formulas to provide all the necessary nutrients, among them minerals. Minerals uptake depends not only on mineral content but also on their bioavailability which, in turn, is affected by the different components of the infant formulas. An understanding of these effects would help to improve mineral bioavailability. This work reviews the influence of endogenous (proteins and phytates) and added (ascorbic and citric acid) components in infant formulas on the bioavailability of nutritionally important mineral elements (calcium, zinc, iron and copper) and their interactions. Special attention is given to the influence of protein, which is positive for calcium and negative for iron absorption. The marked negative effect of phytates on iron and zinc absorption can be counteracted by a dephytinization process. Of the added compounds, ascorbic acid has a positive effect on iron absorption that depends on the molar ratio between ascorbic acid and iron. In fact, adding ascorbic acid can counteract the negative effect of phytic acid on iron absorption but does not alter the effect of phytic acid on zinc absorption. The null effect of an increase in citric acid content can be ascribed to the fact that the citrate contents of infant formulas are already high. One of the most important element interactions is the negative effect of calcium on zinc and iron intestinal absorption and also the interaction between zinc and iron. These interactions deserve our attention because these minerals are essential to infants’ growth and development.
Treatment and Prevention of RSV Bronchiolitis
Authors: Dominguez Karen D.
Published: August 2002

Respiratory syncytial virus is a leading cause of bronchiolitis and pneumonia in children worldwide, resulting in significant morbidity and mortality in high-risk individuals. The pediatric populations at high risk for severe RSV infections include patients with cardiac disease, lung disease, immunosuppression, premature birth or healthy infants less than six months of age. Supportive care is the primary treatment of RSV lower respiratory tract infections. Other treatment regimens include the use of bronchodilators and anti-inflammatory agents; however, the use of these agents is controversial due to lack of evidence of efficacy in all studies. Ribavirin, an antiviral agent, has been administered for the treatment of RSV lower respiratory tract infections, but its efficacy has been questioned due to flawed study designs. RSV-IVIG and palivizumab are approved for the prevention of RSV infection in selected children at high risk for serious disease. These agents are equally efficacious and expensive; however, the cost-effectiveness of prophylaxis is unclear. Currently, no vaccines for RSV are available for general use, but research in the area continues. Until a safe, effective and relatively inexpensive method for prophylaxis is available, RSV infections will continue to cause significant morbidity and mortality in children.
Determination of Fracture Toughness, GC of Graphite/Epoxy Composites from a Cracked Lap Shear (CLS) Specimen
Authors: Rhee Kyong Y. , Chi Chang H.
Published: August 2002

Previously, the work factor approach was applied to determine fracture toughness, Gc of unidirectional graphite/epoxy CLS specimen, and it is required to apply the approach to determine Gc of multi-directional CLS specimen. In this work, the elastic work factor, η el form of multi-directional CLS specimen was calculated numerically as a function of delamination length in order to investigate stacking sequence effect on η el. The calculated η el was applied experimentally to determine fracture toughness, G c of multi-directional ([0/±45/0] s/[02/±452/02] s, [0/±45/0] s/[02±452/902] s, and [902/02] s/[04/904] s for the lap and the strap) graphite/epoxy composites. For each case, the Gc values determined from the η el approach were compared with those determined from the compliance method. Numerical results show that η el is not affected by the fiber angles of plies, and η el is linearly related to delamination length. It was found from the experimental results that Gc determined from the η el approach is in a maximum 15% range of difference with that determined from the compliance method for each case. It was also found from the SEM examination that delamination propagated irregularly through interfaces of lap and strap (8th and 9th plies) for [902/02] s/[04/904] s case while no delamination transfer was observed for [0/±45/0] s/[02/±452/02] s and [0/±45/0] s/[02/±452/902] s cases.
Immune-Based Therapies for the Management of HIV Infection: Highly Active Antiretroviral Therapy and Beyond
Authors: Ansari Aimee F. , Etzel Joseph V.
Published: August 2002

The widespread use of highly active antiretroviral therapy (HAART) has had a significant impact on reducing the incidence of opportunistic infections in patients with the Acquired Immunodeficiency Syndrome (AIDS) and reducing the overall morbidity and mortality associated with this disease. However, the use of HAART is often associated with adverse effects, significant drug interactions, high cost and the emergence of viral resistance in a significant percentage of treatment recipients. In addition, the clinical efficacy of HAART in terms of viral eradication appears to be limited due to the presence of reservoirs of latent virus within HAART-experienced patients. Because of these and other limitations associated with antiretroviral therapies, new therapeutic strategies are being developed to restore the normal function of the immune system and improve patient outcomes. The purpose of this article is to review some of the more promising investigational immune-based therapies and their potential role in the management of Human Immunodeficiency Virus infection.
A Local Model for Bending of Weak Core Sandwich Plates
Authors: Whitney James M.
Published: August 2002

A bending theory is developed for a three-layer sandwich plate consisting of a weak core and two unequal face sheets. In the model, the core and face sheets are modeled as separate homogeneous plates with an assumed stress field, which satisfies equilibrium point-by-point. Local bending, including shear deformation, of the face sheets is taken into account. Although the usual assumption of negligible in-plane stresses in conjunction with a weak core is adopted, the effects of interlaminar core shear and normal stresses, along with transverse core flexibility, are included in the analysis. The corresponding displacement field consists of a combination of assumed and weighted displacements. Field equations are developed from Reissner’s energy theorem, and appropriate continuity conditions between the core and face sheets are enforced. The theory is applied to a rectangular plate subjected to a distributed load and to an end-loaded cantilever plate under cylindrical bending.
Management Considerations for Chronic Asthma
Authors: Bourdet Sharya Vaughan , Williams Dennis
Published: August 2002

Asthma is a common chronic disease affecting millions of individuals in the United States. Appropriate management and prevention of asthma symptoms is essential in order to maintain quality of life and reduce healthcare costs. Published consensus guidelines provide recommendations for asthma management and emphasize pharmacologic and nonpharmacologic components for long-term management. Major components of asthma management include environmental control measures, patient education and self-management, pharmacotherapy and periodic assessment. Since publication of the guidelines in 1997, there has been additional research and advances in our knowledge and understanding of asthma. Ongoing research focuses on issues such as regular versus as needed use of short-acting bronchodilators, early initiation of inhaled corticosteroids, safety of inhaled corticosteroids in children with asthma, combination therapy with inhaled corticosteroids and other long-term control agents, and reduction of inhaled corticosteroid doses. Advances in therapy and new knowledge about appropriate management strategies should be incorporated into clinical management strategies.
Note. Visual and Instrumental Color Evaluation in Red Wines
Authors: Martínez J. A. , Melgosa M. , Pérez M. M. , Hita E. , Negueruela A. I.
Published: August 2002

The color of 15 red wines from several wineries within the renowned wine-producing region Rioja (Northern Spain) was measured by spectrophotometric and spectroradiometric techniques and was visually assessed in a pair-comparison experiment by a panel of 10 experienced observers having normal color vision. Correlation between instrumental color measurements made by spectrophotometric and spectroradiometric techniques was very low, as expected from major differences in the experimental conditions employed (different illumination, path lengths and glass effects). Spectroradiometric measurements at the center of the wine sampler and at positions displaced 1 cm in the horizontal and vertical directions were quite different, mainly because of an increase of the lightness L*, the average color differences between them being high (3.5 and 2.6 CIELAB units, respectively). A 50% acceptance percentage resulted for a color difference of 2.8 CIELAB units, using a reference anchor-pair of wine samples with 4.0 CIELAB units. Thus, a value around 3.0 CIELAB units should be considered a preliminary estimate of the acceptable tolerance by the human eye for red wines poured in standard wine samplers.
Characterization of Matrix Crack-Induced Laminate Failure—Part II: Analysis and Verifications
Authors: Johnson Patrick , Chang Fu-Kuo
Published: August 2002

A two-part investigation was performed to study the stiffness response and strength of composite laminates subjected to uniaxial tension. In Part I, experimental testing was performed to characterize the matrix crack-induced damage progression and failure modes in composite laminates under uniaxial tension loading conditions. In Part II, analytical models were developed to account for the damage modes observed in the experimental investigation. Models for matrix crack-induced delamination, matrix crack-induced microcracking, and matrix crack-induced edge delamination were developed. Model predictions were compared with experimental data. The proposed models were integrated and implemented in the computer code, PDCell. The code was then used to predict the stiffness response and failure of composite laminates subjected to tensile loading. Code predictions were used to evaluate the effects of ply orientation, ply group thickness, loading direction, and stacking sequence on laminate tensile strength. The predictions from the code were compared with available test data in the literature.
Blowing Agent Effect on Extensional Viscosity Calculated from Fiber Spinning Method for Foam Processing
Authors: Ramesh N. S. , Lee S. T.
Published: August 2002

This fundamental study investigates the blowing agent (isopentane) on the extensional viscosity of LDPE at appropriate strain rates and then correlates to the foaming process. The main purpose was to calculate extensional viscosity growth function as a function of extrusion rate and time with and without the presence of isopentane in LDPE. A simple theological technique using the Haake capillary rheometer with pulling attachments was used in the study. The experimental technique is simple and cost effective, but a powerful tool to screen new resins for foam processing applications.
Hygrothermal Effects on Painted and Unpainted Glass/Epoxy Composites—Part B: Degradation Studies
Authors: Pavan Raja M.V. , Saravanan V. , Dinesh A. R. , Rao Y. J. , Srihari Shylaja , Revathi A.
Published: August 2002

Studies were conducted on the degradation of ILSS and compression strength properties of glass/epoxy composite specimens painted and unpainted that were subjected to immersion in a water bath maintained at 323 K.

It is found that both ILSS and compressive strength of the composite degraded more in the case of unpainted specimens (coded L0) compared to the painted ones ( L1 or L2). Further, the specimens with a thicker paint coat ( L2) degraded less than those with a thinner paint coat ( L1).
CONTINUITY PROPERTIES OF SCHRÖDINGER SEMIGROUPS WITH MAGNETIC FIELDS
Authors: BRODERIX KURT , HUNDERTMARK DIRK , LESCHKE HAJO
Published: August 2002

The objects of the present study are one-parameter semigroups generated by Schrödinger operators with fairly general electromagnetic potentials. More precisely, we allow scalar potentials from the Kato class and impose on the vector potentials only local Kato-like conditions. The configuration space is supposed to be an arbitrary open subset of multi-dimensional Euclidean space; in case that it is a proper subset, the Schrödinger operator is rendered symmetric by imposing Dirichlet boundary conditions. We discuss the continuity of the image functions of the semigroup and show local-norm-continuity of the semigroup in the potentials. Finally, we prove that the semigroup has a continuous integral kernel given by a Brownian-bridge expectation. Altogether, the article is meant to extend some of the results in B. Simon's landmark paper [Bull. Amer. Math. Soc.7 (1982) 447] to non-zero vector potentials and more general configuration spaces.
LONG RANGE SCATTERING AND MODIFIED WAVE OPERATORS FOR SOME HARTREE TYPE EQUATIONS I
Authors: GINIBRE J. , VELO G.
Published: August 2002

We study the theory of scattering for a class of Hartree type equations with long range interactions in space dimension n≥3, including Hartree equations with potential V(x)= λ|x|-γ with γ<1. For 1/2<γ<1 we prove the existence of modified wave operators with no size restriction on the data and we determine the asymptotic behaviour in time of solutions in the range of the wave operators.
LOOKING BEYOND THE THERMAL HORIZON: HIDDEN SYMMETRIES IN CHIRAL MODELS
Authors: SCHROER B. , WIESBROCK H.-W.
Published: August 2002

In thermal states of chiral theories, as recently investigated by H.-J. Borchers and J. Yngvason, there exists a rich group of hidden symmetries. Here we show that this leads to a radical converse of of the Hawking–Unruh observation in the following sense. The algebraic commutant of the algebra associated with a (heat bath) thermal chiral system can be used to reprocess the thermal system into a ground state system on a larger algebra with a larger localization space-time. This happens in such a way that the original system appears as a kind of generalized Unruh restriction of the ground state sytem and the thermal commutant as being transmutated into newly created "virgin space-time region" behind a horizon. The related concepts of a "chiral conformal core" and the possibility of a "blow-up" of the latter suggest interesting ideas on localization of degrees of freedom with possible repercussion on how to define quantum entropy of localized matter content in Local Quantum Physics.
NEW PHENOMENA IN THE NEIGHBORHOOD OF THE CODIMENSION-TWO BIFURCATION IN THE TWIN-WELL DUFFING OSCILLATOR
Authors: SZEMPLIŃSKA-STUPNICKA W. , ZUBRZYCKI A. , TYRKIEL E.
Published: August 2002

In this paper, we study effects of the secondary bifurcations in the neighborhood of the primary codimension-two bifurcation point. The twin-well potential Duffing oscillator is considered and the investigations are focused on the new scenario of destruction of the cross-well chaotic attractor. The phenomenon belongs to the category of the subduction scenario and relies on the replacement of the cross-well chaotic attractor by a pair of unsymmetric 2T-periodic attractors. The exploration of a sequence of accompanying bifurcations throws more light on the complex phenomena that may occur in the neighborhood of the primary codimension-two bifurcation point. It shows that in the close vicinity of the point there appears a transition zone in the system parameter plane, the zone which separates the two so-far investigated scenarios of annihilation of the cross-well chaotic attractor.
POSITIVE ALTERNATING LINKS ARE POSITIVELY ALTERNATING
Authors: NAKAMURA TAKUJI
Published: August 2002

By using a result of P. R. Cromwell on homogeneous links which contain both positive links and alternating links, we prove that any reduced alternating diagram of a positive alternating link is positive.