Structural Stability

The work in this report represents how wind turbine towers are designed to give maximum stability in extreme conditions. Different stability criterion are explained and analyzed both analytically and numerically with the help of different standards (euro codes, AISC). For numerical analysis all task are performed on finite element package Abaqus. Two different tubular tower models are first analyzed and checked whether they satisfied stability criterions (deflection, local buckling). It was found that the both the towers are safe against the local buckling and stable under the extreme wind loading. The methodologies adopted in designing wind turbine tower to achieve an optimized result like, minimization of mass, maximization of natural frequency or maximization of stiffness at the end of the report is done. During optimization is observed that the 250kw tower model gives economical result if its design for the variable thickness i.e. less material required for manufacture which reduces its cost.

We demonstrate how by taking better account of electron correlations in the 3d shell of metal ions in nickel oxide it is possible to improve the description of both electron energy loss spectra and parameters characterizing the structural stability of the material compared with local spin density functional theory.

Today the use of glass into the edil sector is not only related to the facade application. In fact, glass as a structural material is always more largely used e.g. as beam and plate elements
that are able to carry loads. Their structural interaction is often due to mechanical connections.
This work has been written to analyse and to implement the knowledge about the flexo-torsional stability of these structural elements. Based on earlier contributions of literature and
extended parametric Finite-Element (FE) numerical investigation, a little gap is presented between the analytic and numerical analysis of the beneficial contribution to the structural
glass beam stability by the lateral restraints. This gap is due to the local effects around lateral mechanical restraints. This difference comes to light when we design the connectors. At first, they are designed like a punctual restraint and at the latter like a hole. In conclusion, a generalized buckling design curve, able to account for the structural contribution and provided by structural mechanical joints is proposed for a rational and conservative LTB verification. This verification is made by a comparison between analytic and numerical simulations outputs.

This paper presents the main features and organization of CADAM, a computer program that has been developed for the static and seismic stability evaluations of concrete gravity dams. CADAM is based on the gravity method using rigid body equilibrium and beam theory to perform stress analyses, compute crack lengths, and safety factors. Seismic analyses could be done using either the pseudo-static or a simplified response spectrum method. CADAM is primarily designed to provide support for learning the principles of structural stability evaluation of gravity dams. It could also be used for research and development on stability of gravity dams. In adopting several worldwide published dam safety guidelines, a large number of modeling options have been implemented regarding (a) crack initiation and propagation, (b) effects of drainage and cracking under static, seismic, and post-seismic uplift pressure conditions, and (c) safety evaluation formats (deterministic allowable stresses and limit states, probabilistic analyses using Monte Carlo simulations). Structural stability evaluation of a 30m dam is presented to illustrate the use of CADAM that is available free from the web site:

Ground deformation monitoring in tunnelling is a common means for selecting and controlling the excavation and support methods among those predicted in design, ensuring safety during tunnel excavation (including personnel safety inside the tunnel and safety of structures located at ground surface) and construction quality. This paper describes the types of ground deformation measurement often used in tunnelling, the difficulties in obtaining these measurements, the methods most commonly used for their evaluation, and the use of deformation measurements (a) in the selection of tunnel excavation and support systems and (b) in establishing early warning systems against ground collapse or damage to structures at ground surface.

Il volume introduce all'ampia problematica dell'analisi non lineare delle strutture, essenziale per giungere ad una stima delle loro capacità portante e definirne la sicurezza rispetto al collasso.

L'attenzione è posta in particolare sull'analisi del comportamento elasto-plastico  e sull'analisi dei fenomeni di instabilità delle strutture, con riferimento quindi a strutture tozze dove sono prevalenti le non linearità fisiche del materiale di cui sono composte, e a strutture snelle dove le non linearità prevalenti sono di tipo geometrico legate ai concetti di instabilità delle relative configurazioni di equilibrio.

L'approccio non lineare all'analisi delle strutture, per l'impegno di calcolo notevolmente più pesante di quello richiesto da analisi a base convenzionale,  è conseguibile solo nel quadro di una strategia numerica di tipo automatico di analisi. A tal fine le metodologie di analisi non lineare sviluppate nel testo sono finalizzate ad una implementazione automatica nel quadro di una strategia di discretizzazione agli elementi finiti.

Mentre fino a pochi anni addietro tale approccio risultava di interesse specialistico o accademico, la potenza di calcolo e la diffusione dei nuovi microcalcolatori a basso costo rende adesso possibile, e lo renderà sempre più tra breve, un uso generalizzato di procedimenti di verifica strutturali basati su analisi di tipo non lineare.

The objective of the paper is the compilation, review and dissemination of updated scientific knowledge on lime theory and technology in the field of heritage conservation.The strong evidence of the last decade's research on the positive effect of the -not demonstrable by a chemical equation – 'key' missing link of the maturation process is highlighted. It is demonstrated that the exceptional performance characteristics of durable lime based mortars predominately rely on the capacity for rapid, efficient and extensive carbona-tion of the air-hardening phase of limes, in particular when matured (nanoparticle wet slaked) lime putties are used; and on the chemical and mechanical stability of the strength components (principally CSHs) of the hydraulic phase of limes, which is higher in their more crystalline forms of historical lime-pozzolan mixtures than in their amorphous forms of modern cements. Hence, physicochemical adhesion and cohesion bonds both at the lime matrix and at the binder/aggregate interfaces are ensured imparting minimization of cracks and durability to lime based mortars and historic masonries.The comprehensive documentation of the former leads to optimal materials and procedures to preserve our cultural heritage.
Resumo O objectivo do presente artigo é a compilação, revisão e disseminação do actual conhecimento científico sobre teoria e tecnologia da cal no campo da conservação do património. Com base na investigação da última década, são destacados os fortes indícios do efeito positivo – não demonstrável por equação química – do elo perdido 'chave', o processo de maturação. É demonstrado que as excepcionais características de desempenho das argamassas à base de cal mais duráveis dependem predominantemente das suas capacidades para uma rápida, eficiente e extensa carbonatação da fase de presa aérea da cal, em particular quando é usada cal em pasta com maior tempo de maturação (extinção húmida ao nível das nanopartículas); e da estabilidade química e mecânica dos com-ponentes de resistência (principalmente silicatos de cálcio hidratados (CSHs)) da fase hidráulica da cal, que é mais elevada nas for-mas mais cristalinas das misturas históricas de cal e pozolana do que nas formas amorfas dos cimentos modernos. Deste modo são asseguradas as ligações fisico-químicas por adesão e por coesão, quer na matriz de cal, quer nas interfaces ligante/agregado, conferindo minimização de fissuras e durabilidade a argamassas à base de cal e alvenarias históricas. Uma abrangente documentação destes proces-sos permitirá a obtenção de materiais e procedimentos progressivamente mais adequados à preservação do nosso património cultural. Palavras-chave Maturação; Cal em pasta; Argamassa de cal; Componentes de resistência; Estabilidade estrutural.

The use of general descriptive names, registered names, trademarks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use.

Discrete lateral restraints offer an effective means of stabilising beams against lateral-torsional buckling. Design expressions for simply-supported beams braced regularly along their span with elastic restraints, based on analytically-derived formulae, are presented herein. These include the minimum restraint stiffness required to force the beam to buckle in between the restraint nodes and the forces induced in the restraints, along with a brief treatment of the critical moment of the beam. It is demonstrated that there is close agreement between the values obtained from the design formulae and their original analytical counterparts. These are also compared with the results from design formulae based on analogous column behaviour, an approach commonly used in design codes. It is found that the column rules used by design codes return values that, when compared with the results of the current analysis, are overly conservative for cases where the restraints are positioned at the compression flange of the beam but unsafe for restraints positioned at the shear centre.

Although there has been a substantial increase over the past decade in studies that have examined the psychosocial correlates of spirituality/religiosity in adolescence, very little is known about spirituality/ religiosity as a domain of development in its own right. To address this limitation, the authors identified configurations of multiple dimensions of spirituality/religiosity across 2 time points with an empirical classification procedure (cluster analysis) and assessed development in these configurations at the sample and individual level. Participants included 756 predominately Canadian-born adolescents (53% female, 47% male) from southern Ontario, Canada, who completed a survey in Grade 11 (M age ϭ 16.41 years) and Grade 12 (M age ϭ 17.36 years). Measures included religious activity involvement, enjoyment of religious activities, the Spiritual Transcendence Index, wondering about spiritual issues, frequency of prayer, and frequency of meditation. Sample-level development (structural stability and change) was assessed by examining whether the structural configurations of the clusters were consistent over time. Individual-level development was assessed by examining intraindividual stability and change in cluster membership over time. Results revealed that a five cluster-solution was optimal at both grades. Clusters were identified as aspiritual/irreligious, disconnected wonderers, high institutional and personal, primarily personal, and meditators. With the exception of the high institutional and personal cluster, the cluster structures were stable over time. There also was significant intraindividual stability in all clusters over time; however, a significant proportion of individuals classified as high institutional and personal in Grade 11 moved into the primarily personal cluster in Grade 12.

Soil fertility, one of the important determinants of agricultural productivity, is generally thought to be supplemented through the application of nutrients mainly through inorganic fertilizers. The physical fertility of the soil, which creates suitable environment for the availability and uptake of these nutrients, is generally ignored. The present study aims to characterize the soil physical environment in relation to the long term application of farm yard manure (FYM) and inorganic fertilizers in rice–wheat. The treatments during both rice and wheat crops were (i) farm yard manure @ 20 t ha−1 (FYM); (ii) nitrogen @ 120 kg ha−1 (N120); (iii) nitrogen and phosphorus @ 120 and 30 kg ha−1 (N120P30) and (iv) nitrogen, phosphorus and potassium @ 120, 30 and 30 kg ha−1 (N120P30K30) in addition to (iv) control treatment, i.e. without any fertilizer and/or FYM addition. The treatments were replicated four times in randomized block design in a sandy loam (typic Ustipsament, non-saline, slightly alkaline). Bulk density, structural stability of soil aggregates and water holding capacity of 0–60 cm soil layer were measured.The average mean weight diameter (MWD) was highest in FYM-plots both in rice (0.237 mm) and wheat (0.249 mm) closely followed by that in N120P30K30 plots. The effect of FYM in increasing the MWD decreased with soil depth. The addition of both FYM and N120P30K30 increased the organic carbon by 44 and 37%, respectively in rice. The total porosity of soil increased with the application of both FYM and N120P30K30 from that in control plots. In 0–15 cm soil layer, the total porosity increased by 25% with FYM from that in control plots. This difference decreased to 13% in 15–30 cm soil layer. The average water holding capacity (WHC) was 16 and 11% higher with FYM and N120P30K30 application from that in control plots. The MWD, total porosity and WHC improved with the application of balanced application of fertilizers. The grain yield and uptake of N, P and K by both rice and wheat were higher with the application of FYM and inorganic fertilizers than in control plots. The carbon sequestration rate after 32 years was maximum (0.31 t ha−1 year−1) in FYM-plots, followed by 0.26 t ha−1 year−1 in N120P30K30-plots, 0.19 t ha−1 year−1 in N120P30 and minimum (0.13 t ha−1 year−1) in N120-plots.

The AXO 4 monazite-type compounds form an extended family that is described in this review in terms of field of stability versus composition. All the substitution possibilities on the cationic and anionic sites leading to the monazite structure are reported. The phosphate, vanadate, chromate, arseniate, sulphate and silicate families are described and the unit-cell parameters of pure compounds and solid solutions are gathered. The stability limits of the monazite-type structure are discussed versus several models generally correlated with geometric criteria. The effects of physicochemical parameters such as pressure, temperature and irradiation on the monazite-type structure stability are also discussed. The structural relationships between the monazite structure and the related structures (zircon, anhydrite, barite, AgMnO 4 , scheelite and monoclinic BiPO 4 , CaSeO 3 , rhabdophane and SrNp(PO 4 ) 2 ) are described.

The aim of the paper is to describe hydraulic stability of rock-armoured low-crested structures on the basis of new experimental tests and prototype observations. Rock armour stability results from earlier model tests under non-depth-limited long-crested head-on waves are reviewed.

Tungsten oxide (WO 3 ) thin films have been produced by KrF excimer laser (λ ) 248 nm) ablation of bulk ceramic WO 3 targets. The crystal structure, surface morphology, chemical composition, and structural stability of the WO 3 thin films have been studied in detail. Characterization of freshly grown WO 3 thin films has been performed using X-ray diffraction (XRD), atomic force microscopy (AFM), energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy (RS), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) measurements. The results indicate that the freshly grown WO 3 thin films are nearly stoichiometric and well crystallized as monoclinic WO 3 . The surface morphology of the resulting WO 3 thin film has grains of ∼60 nm in size with a root-mean-square (rms) surface roughness of 10 nm. The phase transformations in the WO 3 thin films were investigated by annealing in the TEM column at 30-500°C

Aerobic granulation is drawing increasing global interest in a quest for an efficient and innovative technology in wastewater treatment. Developed less than two decades ago, extensive research work on aerobic granulation has been reported. The instability of the granule, which is one of the main problems that hinder practical application of aerobic granulation technology, is still to be resolved. This paper presents a review of the literature in aerobic granulation focusing on factors that influence granule formation, granule development and their stability in the context of sludge granulation. The review attempts to shed light on the potential of developing granules with adequate structural stability for practical applications. The possibilities and perspective of using stored granule as inoculums for rapid startup, and as microbial supplement to enhance treatment of bioreactor systems are also discussed.

Living cells contain a variety of biomolecules including nucleic acids, proteins, polysaccharides, and metabolites as well as other soluble and insoluble components. These biomolecules occupy a significant fraction (20e40%) of the cellular volume. The total concentration of biomolecules reaches 400 g L �1 , leading to a crowded intracellular environment referred to as molecular crowding. Therefore, an understanding of the effects of molecular crowding conditions on biomolecules is important to broad research fields such as biochemical, medical, and pharmaceutical sciences. In this review, we describe molecular conditions in the cytoplasm and nucleus, which are totally different from in vitro conditions, and then show the biochemical and biophysical consequences of molecular crowding. Finally, we discuss the effect of molecular crowding on the structure, stability, and function of nucleic acids and the significance of molecular crowding in biotechnology and nanotechnology. �

In many agricultural soils in the semi-arid and arid mediterranean climates, exposure to cyclic wetting and drying (WD) can reduce aggregate stability. The extent to which soil pretreatment with coal-derived humic substances (HS) can increase aggregate stability in soils exposed to cyclic wetting and drying (WD) was evaluated in this study. The soils studied are an Acireale silty clay loam from Sicily, a Principina silt loam from Tuscany and a Bovolone loam from Venetia in Italy. On each soil eight rates of the HS (0, 0.001, 0.01, 0.05, 0.10, 0.50, 1.00 and 10.00 g/kg of soil) and four WD cycles (0, 3, 6 and 9) were used to assess any changes in stability.

A series of plasmid-based expression vectors have been constructed allowing stable intracellular expression of recombinant proteins in Bacillus subtilis strains. These expression vectors are based on the recently described Escherichia coli-B. subtilis shuttle vector pMTLBS72 which replicates as theta circles. Besides the weak constitutive promoter P lepA , we inserted three diVerent controllable promoters: P gsiB which can be induced by heat and acid shock, and by ethanol, P xylA and P spac which respond to the addition of xylose and IPTG, respectively. The versatility of these expression vectors was demonstrated by fusing their promoters to a reporter gene and by overexpression of the HtpG protein with three of them. All recombinant vectors exhibited full structural stability. 

The aqueous extract of pink-fleshed guava fruit was encapsulated by spray-drying with maltodextrin (MD), arabic gum (AG), and their mixtures. The use of AG improves the fluidity during the drying process but produces an undesirable residual taste and decreases the thermal stability in the final microencapsulated powders. Retention of some aroma-active guava volatiles in the powders was confirmed by using HS-SPME-GC-MS analyses. The sensory analyses performed by two sets of non-trained panellists (adults and children) allow to select the most promising powders (MD and AGMD-1). They were physicochemically characterised and subjected to thermal (TGA and DSC) and morphologic (SEM) analyses. The successful production of spherical microencapsulates was also confirmed. From a storage stability study at two relative humidity (RH) conditions (74% and 94%), a strong influence of this parameter in the structure stability of microencapsulates and aroma release was found. The solids developed in this study represent an innovative and natural processed product from guava fruits which can be incorporated into different food products due to their sensory properties.

The stability of steel beams with discrete lateral restraints is analysed using the Rayleigh–Ritz method, with the degrees-of-freedom being represented by Fourier series. Linear eigenvalue analysis of the system shows that the system buckles into one of two classes of mode, either node-displacing or between bracing nodes. Buckling mode progression behaviour is examined and limiting characteristics of the system are found. Comparison is made with a single harmonic representation of the DOFs, which is found to lead to erroneous predictions. Validation of the analysis is performed using the finite element method and numerical continuation. Finally, it is shown that design formulae based on analogous column behaviour can return both conservative and unsafe results, depending on brace location.

Has the persistence of inflation in the United States changed since 1965? We estimate the persistence of inflation over time using different measures and estimation procedures and we produce confidence intervals for our estimates as well as formal tests of unchanged persistence. We find that inflation persistence has been high and approximately unchanged in the U.S. over our sample period. We reconcile our results with other studies that reached different conclusions. r (R. Reis).

In order to investigate the validity of a coupled mill vibration model presented in the dynamic rolling formulation, this paper presents the results of dynamic characteristics examining rolling force variations in response to rolling parameters. Under the given steady state rolling condition, the unstable vibrational modes with corresponding frequencies are identified and stability analysis is also performed to demonstrate that the proposed model is highly dependent on the rolling speed and friction coefficient with an assumed negative gradient of friction coefficient. To further find the transient characteristics and the direct influences of the friction coefficient and rolling speed on the mill chatter, the derived equations of motion of the system are solved using Runge-Kutta numerical integration method. Simulations are carried out to reveal the chatter sources, which gives rise to unstable rolling vibrations. INTRODUCTION Mathematical models representing the cold rolling mechanism have attracted extensive attention, resulting in analytical, numerical or graphical solutions achieved under a variety of assumptions and simplifications. One of the important parts in modeling chatter mechanism is to establish a well-defined dynamic model of the rolling process that entails complicated relationship between rolling variables. A model that presents the rolling force as a function of rolling variables must explain dynamic interactions between the rolling process

Soil biota play a crucial role in influencing soil structure and related soil physical properties. In particular, an abundant literature shows that earthworms, through their burrowing and feeding activities, influence particle size distribution, organic matter content, organic matter location, soil aggregation, aggregate stability and tensile strength, soil roughness, and water infiltration. All those properties greatly influence soil erodibility and soil

The synthesis of geopolymer matrixes from coal (co-)combustion fly ashes as the sole source of silica and alumina has been studied in order to assess both their capacity to immobilise the potentially toxic elements contained in these coal (co-)combustion by-products and their suitability to be used as cement replacements. The geopolymerisation process has been performed using (5, 8 and 12 M) NaOH solutions as activation media and different curing time (6-48 h) and temperature (40-80 degrees C) conditions. Synthesised geopolymers have been characterised with regard to their leaching behaviour, following the DIN 38414-S4 [DIN 38414-S4, Determination of leachability by water (S4), group S: sludge and sediments. German standard methods for the examination of water, waste water and sludge. Institut für Normung, Berlin, 1984] and NEN 7375 [NEN 7375, Leaching characteristics of moulded or monolithic building and waste materials. Determination of leaching of inorganic components with the di...

Earthworms are known to significantly influence soil aggregate stability and hence to regulate underlying ecosystem functions such as soil organic matter (SOM) decomposition and soil erosion. However, the available research information on this aspect in the tropics, and especially in Asia, is rather scanty. The aims of this paper are therefore to study the influence of Amynthas khami, an anecic earthworm species, on soil structural properties on one hand, and to determine the factors involved and the consequences for the soil matrix properties on the other hands. Investigations were carried out in different management systems ranging from low to high above-ground casts density. We measured the physical and chemical properties and water behavior (mean weight diameter: MWD, and water drop penetration time: WDPT) of casts and those of the surrounding soil aggregates (control). Pore space was quantified using a morphological approach and 2D image analysis. Soil aggregate stability was primarily specific for each-land use type and afterwards affected by earthworm activity within each ecosystem. Earthworm casts were always more stable than control surrounding soil aggregates. Casts were characterized by higher pH, C, polysaccharides, Ca 2+ , Mg 2+ and K + contents. Conversely, the particle size fraction and the content of oxides (Al cbd and Fe cbd ) were not significantly affected by earthworm activity. Soil porosity was sharply decreased in casts as compared to the surrounding soil aggregates and casts were characterized by the absence of packing void poroids and large pores N 50,000 µm 2 . Regressions between soil physico-chemical properties and MWD underlined the relationships between SOM (C and polysaccharide content), pH, Ca 2+ content, soil porosity, and the structural stability of cast aggregates. Surprisingly, the abundance of casts on the soil surface was not related to the bulk density of the soil matrix, suggesting that cast aggregates are not integrated into it or that they are integrated with different soil structural characteristics.

An increasing demand for high-quality, low cost Earth imagery has led to the requirement for improved structural stability of the satellite instruments providing the imagery. This translates into camera structures capable of maintaining very high levels of dimensional stability over their lifetimes. There are several adequate technical solutions to this problem-for instance onboard mechanisms that can re-align optical components operationally, or unconventional materials such as silicon carbide. This paper investigates the current state of the art in solutions which are based on conventional materials and joining techniques to maintain high levels of stability without the need for mechanisms. The purpose of this article is to give an overview of the most important factors that should be taken into account when designing stable structures for space applications. Whilst the use in Earth observation has been highlighted in this paper the overview is applicable to all applications that use space optics. For completeness, the methods to verify the design have also been briefly described.

Fungus-growing termites enrich their nest structures with clays and can modify the mineralogical properties of silicate clays. In order to determine the role of clay in soil structural stability of mounds, we measured the physico-chemical properties and the water behaviour of termite mound soil. Two opposing tendencies control the structural stability of termite mound soil: (i) the increase of clay content in the mound leading to a decrease of pore sizes and rate of water diffusion; and (ii) the swelling of 2:1 clay types when water penetrates into the soil leading to a breakdown of the mound soil. Although soil organic matter (SOM) is usually considered as a cement ensuring the soil structural stability of mound soil, this study shows that SOM has a negligible role and that clay can be considered as a key component to understand the structural stability of Macrotermes mound soil.

I crolli di cavità sotterranee in ambiente urbano pongono un rischio progressivamente crescente. Tra i fattori che contribuiscono a ridurre nel tempo la stabilità delle gallerie vi sono il degrado continuo delle caratteristiche meccaniche dei terreni, la progressiva erosione dovuta a perdite delle reti idriche e delle fognature urbane e i carichi in superficie. La loro pericolosità è accresciuta dal fatto che il collasso avviene
repentinamente, con cedimenti molto ridotti fino a poco prima del crollo totale. La valutazione di stabilità viene per lo più condotta con procedure empiriche o modelli meccanici estremamente semplificati. Le recenti evoluzioni delle tecniche di rilievo e la possibilità di ottenere una descrizione numerica fedele della geometria delle cavità rendono praticabile un approccio meccanico con modelli ad elementi finiti ed una
stima meglio approssimata delle condizioni di stabilità.

Summary. In the natural environment plants are well adapted to minimize damages which only occurs under extreme conditions. In the frame of "physi- ological window" mild drought induces in plants regulation of water loss and uptake allowing maintenance of their leaf relative water content within the limits where the photosynthetic capacity shows no or little changes. But severe drought induces

Stiffened plates are used in many civil engineering, aerospace and marine structures. Adding stiffeners to a plate provides significant strength and stability while minor increase in weight to the structure. However, the mechanical behavior of stiffened plates is very complex. Numerous investigations were carried out in the past 50 years to examine the effects of stiffener/plate assembly geometries on buckling and collapse strength. Generally, there are two basic theories in literature for determining the optimal stiffener geometry of stiffened plates: the first one is based on the linear elastic or eigenvalue buckling theory, while the second one is centered around determining the ultimate strength or collapse load of the structure. In present paper, the critical stiffener geometries of longitudinally stiffened plates with flat stiffeners under uniaxial compression are investigated . Theoretical basis of the study is determining the ultimate strength of the plate considering plasticity and initial imperfections, which gives more rational and accurate result than the stiffener design methods based on the linear elastic buckling theory. Still, the principle of optimization is analogous. Both procedures consider optimal stiffener geometry as the point when further strengthening of the stiffeners becomes irrelevant to the buckling/ultimate strength in regards of the overall plate. Therefore, a series of nonlinear FEM analyses were carried out to determine the ultimate strength of various plate/stiffener assemblies. The numerical model was built in accordance with the Eurocode 3-1-5 standard, as well as the initial imperfection amplitudes and material properties. On the other hand, ultimate strength was computed with effective cross section method (ECSM) also as per EC3-1-5. Finally, results and comparison of the two methods (FEM and ECSM) are evaluated, conclusions about the possible optimal stiffener geometries are discussed.

This paper summarizes the results of the process optimization for SU-8 films with thicknesses 5 μm. The influence of soft-bake conditions, exposure dose and post-exposure-bake parameters on residual film stress, structural stability and lithographic resolution was investigated. Conventionally, the SU-8 is soft-baked after spin coating to remove the solvent. After the exposure, a post-exposure bake at a high temperature T PEB 90 • C is required to cross-link the resist. However, for thin SU-8 films this often results in cracking or delamination due to residual film stress. The approach of the process optimization is to keep a considerable amount of the solvent in the SU-8 before exposure to facilitate photo-acid diffusion and to increase the mobility of the monomers. The experiments demonstrate that a replacement of the soft-bake by a short solvent evaporation time at ambient temperature allows cross-linking of the thin SU-8 films even at a low T PEB = 50 • C. Fourier-transform infrared spectroscopy is used to confirm the increased cross-linking density. The low thermal stress due to the reduced T PEB and the improved structural stability result in crack-free structures and solve the issue of delamination. The knowledge of the influence of different processing parameters on the responses allows the design of optimized processes for thin SU-8 films depending on the specific application.

It is desirable to verify the structural performance based on a multi-hazard approach, taking into account the critical actions the structure in question could be subjected to during its lifetime. This study presents a proposal for a probabilistic model for multi-hazard risk associated with the limit state of collapse for a reinforced concrete (RC) structure subjected to blast threats in the presence of seismic risk. The annual risk of structural collapse is calculated taking into account both the collapse caused by an earthquake event and the blast-induced progressive collapse. The blast fragility is calculated using a simulation procedure for generating possible blast configurations, and verifying the structural stability under gravity loading of the damaged structure, using a kinematic plastic limit analysis. As a case study, the blast and seismic fragilities of a generic four-storey RC building located in seismic zone are calculated and implemented in the framework of a multi-hazard procedure, leading to the evaluation of the annual risk of collapse.

Steel columns in sway and nonsway frames that are spliced along their length generally have a lower strength capacity in compression. This load capacity can be further reduced owing to the inevitable presence of small geometrical imperfections in the form of the out-of-straightness of the column and column segment misalignment. The current work examines the buckling behavior of a framed spliced column with initial imperfections and the possibility of a nonuniform cross section. A geometrically nonlinear model accounting for imperfect elastic buckling behavior is formulated using the differential equations of equilibrium. This is followed by a study of the imperfection sensitivity to the linearly evaluated critical load. A discussion on the variation of the load-carrying capacity with the level of imperfections on a practical spliced column is also presented. The findings suggest that a spliced column can be considered equivalent to a prismatic Euler column, with an appropriate effective length, for design purposes. In this context, some implications for design are deduced from the presented analysis.

Glucose oxidase from Aspergillus niger was purified to homogeneity by hydrophobic interaction and ion-exchange chromatography. Approx. 95% of the carbohydrate moiety was cleaved from the protein by incubation of glucose oxidase with endoglycosidase H and a-mannosidase. Cleavage of the carbohydrate moiety effected a 2 3-30% decrease in the molecular weight and a reduction in the number of isoforms of glucose oxidase. No si~atificant changes were observed in the circular dichroism spectra of the deglyeosylated enzyme. Other properties, such as thermal stability, pH and temperature optima of glucose oxidase activity and substrate specificity were not affected. However, removal of the carbohydrate moiety marginally affecled the kinetics of glucose oxidation and stability at low pH. From these results it appears that the carbohydrate chain of glucose oxidase does not contribute significantly to the structure, stability and activity of glucose oxidase.

This paper summarizes for practitioners the key recommendations of a recent ASCE report for utilizing the notional load approach to design steel columns in unbraced frames.  This method, which has been employed successfully outside the United States, involves the addition of a lateral load to each story and column line which is proportional to the total gravity load applied to it at that level.  The main advantage of the notional load approach is that it eliminates the need to calculate effective length factors.  Sway stability effects are accounted for by increasing the applied moments in the beam-column interaction equations, rather than by reducing the axial capacity.