Structural behaviour of a dry dock with pile-anchored bottom slab

In this article the analysis and theoretical interpretation of the results obtained in the observation of some cross sections of dock 21 of SETENAVE shipyards is described. The deformability of a large construction, whose behaviour showed marked interaction with the surrounding soil was studied. The overall behaviour is strongly affected by the behaviour of a vast zone of piles, densely distributed and subjected to strong tensile and compressive forces. The purpose of theoretical treatment of results obtained directly from the prototype, which are still quite rare, was to improve the knowledge needed for the design of this kind of structures. The interpretation of the results also provided a better knowledge of the behaviour of large groups of piles subjected to tensile forces, which are very difficult to study in the laboratory. The type of problem dealt with is not limited to dry docks anchored on piles. It also concerns other types of structures, either sunk or at earthfill level, such as large resevoirs, nuclear plants, etc.     

Predicting porosity content in triaxial porcelain bodies as a function of raw materials contents

This work describes the relationships observed between the porosity of fired ceramic test pieces and the raw materials contents in the unfired mixture. The investigation was carried out using the mixture experiments design approach coupled with response surface methodology, which enables the calculation of statistically significant models for the properties from a limited number of experimental results. Ten formulations of a clay mixture, potash feldspar and quartz sand were processed in the laboratory under fixed conditions, similar to those used on wall and floor tile industrial practice, and characterized. Closed porosity (CP) was estimated from the analysis of back-scattered SEM photomicrographs, open porosity (OP) was calculated as the product of bulk density and water absorption, and total porosity (TP) was calculated from OP and CP values. Characterization results were used to calculate statistically significant and valid regression equations, relating those properties with the raw material contents in the unfired mixture. For the particular raw materials and processing conditions used, the models clearly show how quartz contributes to increasing OP and the crucial role played by feldspar when CP and TP are to be minimized (circa 3 vol.%), and how the clay content can counteract that effect and lead to maximum closed porosity (∼14 vol.%).     

Signal probability for reliability evaluation of logic circuits

As integrated circuits scale down into nanometer dimensions, a great reduction on the reliability of combinational blocks is expected. This way, the susceptibility of circuits to intermittent and transient faults is becoming a key parameter in the evaluation of logic circuits, and fast and accurate ways of reliability analysis must be developed. This paper presents a reliability analysis methodology based on signal probability, which is of straightforward application and can be easily integrated in the design flow. The proposed methodology computes circuit’s signal reliability as a function of its logical masking capabilities, concerning multiple simultaneous faults occurrence.     

Simple High Performance General Purpose Single Channel Analyser

A simple single channel analyser using standard components is described. High temperature stability (0.002% / °C) and resolution (? 100 ?V) is achieved. The two-level generator circuits described allow full DC coupling of the input pulses. The performance of these circuits is discussed in detail and experimental results presented.     

Janus particle amphiphilicity and capillary interactions at a fluid interface

Studying the behavior of anisotropic particles at fluid interfaces is a rapidly expanding field, as understanding how the introduced anisotropy affects the resulting properties is essential in the engineering of interfacial systems. Surface anisotropic particles, also known as Janus particles (JPs), offer new possibilities for novel applications due to their amphiphilicity and stronger binding to fluid interfaces compared to homogeneous particles. Introducing surface anisotropy creates complexity as the orientation of interfacially bound particles affects interparticle interactions, a contributing factor to the microstructure formation. In this work, we have investigated the microstructure of JP monolayers formed at the air–water interface using particles with different degrees of amphiphilicity and examined the response of the networks to applied compressions. Our findings demonstrate that JPs amphiphilicity is a crucial factor governing their orientation at the interface, which in turn dictates the complexity of the capillary interactions present and the mechanical properties of the ensuing networks.     

A brief abstinence test for college student smokers: A feasibility study.

Cigarette smoking among college students is prevalent and correlated with other unhealthy behaviors. Reinforced abstinence (e.g., contingency management) has been demonstrated to be an effective method for reducing substance use in a variety of populations and across a variety of drugs, including cigarettes. Reinforced abstinence has seldom been used specifically targeting a college student population. A Brief Abstinence Test (BAT) has been used to effectively reduce cocaine use among methadone maintenance patients (Robles, Silverman, Preston, Cone, Katz, Bigelow, & Stitzer, 2000). However, no published studies have investigated the use of a BAT to reduce the use of cigarettes. The current study implemented a 3-week intervention (Baseline 1, BAT, and Baseline 2 weeks) for smoking abstinence among college students. Forty-two percent of the sample met abstention criteria during the BAT. Carbon monoxide and urinalysis scores decreased significantly from Baseline 1 to the BAT phase but did not differ significantly from BAT to Baseline 2. These results suggest that the BAT may have utility initiating abstinence in both clinical and research contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

First-order,buckling and post-buckling behaviour of GFRP pultruded beams. Part 2: Numerical simulation

This work deals with the numerical evaluation of the structural response of simply supported (transversally loaded at mid-span) and cantilever (subjected to tip point loads) beams built from a commercial pultruded I-section GFRP profile. In particular, the paper addresses the beam (i) geometrically linear behaviour in service conditions, (ii) local and lateral-torsional buckling behaviour, and (iii) lateral-torsional post-buckling behaviour, including the effect of the load point of application location. The numerical results are obtained by means of (i) novel Generalised Beam Theory (GBT) beam finite element formulations, able to capture the influence of the load point of application, and (ii) shell finite element analyses carried out in the code Abaqus. These numerical results are compared with (i) the experimental values reported and discussed in the companion paper (Part 1) and (ii) values provided by analytical formulae available in the literature.     

Creep behavior of pultruded GFRP elements – Part 2: Analytical study

This paper presents an analytical study about the viscoelastic time-dependent (creep) behavior of pultruded GFRP elements made of polyester and E-glass fibers. Experimental results reported in Part 1 are firstly used for material characterization by means of empirical and phenomenological formulations – a good general agreement is obtained using the following analytical models: (i) Findley’s power law, (ii) Bruger–Kelvin model and (iii) Prony–Dirichlet series. Based on accelerated characterization methodology – Time-Stress Superposition Principle (TSSP) coupled with Findley’s law, for a reference stress of 20% of the material ultimate stress, an elastic deformation increase of 30% is obtained after 50,000 h. The creep parameters and deformation estimated by using the Findley’s model derivations indicate a consistent prediction of time-dependent deformation and viscoelastic properties of the two types of elements analysed – laminates and beam. A straightforward formulation to predict the time-dependent elastic modulus is applied, showing that the flexural stiffness should be reduced by 25% of its initial value after 1-year and as much as 50% after 50-years. Similarly, the power law coupled to Euler’s classical beam theory suggests a reasonable adaptability to the creep phenomenon in the linear regime and proved to provide accurate predictions for deflections under flexural loading up to 40% of the ultimate strength. After 50 years, under normal service load level (1/3 of the failure load), the total creep deflection will attain almost twice the initial deflection. If taking into account the shear deformation (Timoshenko’s postulated) of the full-size element with “effective” stiffness properties such estimate is reduced nearly 25%.     

Advances on the development of novel heterogeneous catalysts for transesterification of triglycerides in biodiesel

This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work resulted in the selection of CaO and CaO modified with Li catalysts, which showed very good catalytic performances with high activity and stability. In fact FAME yields higher than 92% were observed in two consecutive reaction batches without expensive intermediate reactivation procedures. Therefore, those catalysts appear to be suitable for biodiesel production.     

Squamous cell carcinoma in individuals under 40 years of age

We reviewed all the cases of Squamous Cell Carcinoma in people under 40 years of age, diagnosed histologically at the Dermatopathology Laboratory of the Santa Maria Hospital, from January 1985 to December 1993. The 19 cases detected were analysed for age, sex, occupation, anatomical site of the tumor, evolution, smoke and alcoholic habits, skin phototypes, immunosuppression, previous viral infections, previous radiotherapy or PUVA therapy and associated diseases. A prevalence of an occupation involving more exposure to the sun was found. Males were more affected than females (2.2/1). In 37% of the patients we detected heavy alcoholic habits. The most frequent anatomical site was the lower lip (42%). Patients with skin phototype I were more affected (53%).