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Before the end of the Epoch of Reionization, the Hydrogen in the Universe was predominantly neutral. This leads to a strong attenuation of Ly α lines of z ≳ 6 galaxies in the intergalactic medium. Nevertheless, Ly α has been detected up to very high redshifts (z ∼ 9) for several especially UV luminous galaxies. Here, we test to what extent the galaxy’s local environment might impact the Ly α transmission of such sources. We present an analysis of dedicated Hubble Space Telescope (HST) imaging in the CANDELS/EGS field to search for fainter neighbours around three of the most UV luminous and most distant spectroscopically confirmed Ly α emitters: EGS-zs8-1, EGS-zs8-2, and EGSY-z8p7 at zspec = 7.73, 7.48, and 8.68, respectively. We combine the multiwavelength HST imaging with Spitzer data to reliably select z ∼ 7–9 galaxies around the central, UV-luminous sources. In all cases, we find a clear enhancement of neighbouring galaxies compared to the expected number in a blank field (by a factor ∼3–9×). Our analysis thus reveals ubiquitous overdensities around luminous Ly α emitting sources in the heart of the cosmic reionization epoch. We show that our results are in excellent agreement with expectations from the DRAGONS simulation, confirming the theoretical prediction that the first ionized bubbles preferentially formed in overdense regions. While three UV luminous galaxies already have spectroscopic redshifts, the majority of the remaining fainter, surrounding sources are yet to be confirmed via spectroscopy. JWST follow-up observations of the neighbouring galaxies identified here will thus be needed to confirm their physical association and to map out the ionized regions produced by these sources.

Objetive: The objective of this study is to evaluate the differences between achalasia in Chagas’ disease and idiopathic achalasia in patients admitted to the Hospital de Clínicas de Porto Alegre, by analyzing epidemiologic, clinic, radiologic and manometric findings.Methods: Patients referred to the Hospital de Clinicas de Porto Alegre between November 1996 and December 2001 with suspicion of achalasia, later confirmed by esophageal manometry, were included in the study. In addition to manometric and radiologic findings, patients were assessed for age, sex, symptomsand symptomatic period.Results: Among 51 patients, nine (18%) presented positive serology for Chagas’ disease and 42 (82%) presented negative serology. The latter were considered carriers of idiopathic achalasia. The mean age of patients with achalasia in Chagas’ disease was 62 ± 15 years, while the mean age in the idiopathic group was 43 ± 18 years (P < 0.02). The symptomatic period for patients with achalasia in Chagas’ disease was 74 ± 47 months, and in the idiopathic group, 49 ± 35 months (P < 0.05). Dysphagia, regurgitation, thoracic pain and weight loss, values at the lower esophageal sphincter (basal pressure, post-deglutitive relaxation pressure/duration and total length) and at the esophageal body (amplitude and duration of the post-deglutitive waves) were similar in both groups.Conclusions: The only statistically significant differences found between the two groups were age and length of the symptomatic period, significantly greater in patients with achalasia in Chagas’ disease. These data suggest a greater resistance to the symptoms in older patients., Objetivo: O presente trabalho tem como objetivo avaliar as diferenças entre a acalasia chagásica e a idiopática em pacientes do Hospital de Clínicas de Porto Alegre, através da análise de achados epidemiológicos, clínicos, radiológicos e manométricos.Métodos: Foram estudados pacientes encaminhados ao Hospital de Clínicas de Porto Alegre, entre novembro de 1996 e dezembro de 2001, com suspeita de acalasia, posteriormente, confirmada por manometria esofágica. Além das características manométricas e radiológicas, os pacientes foram avaliados quanto a idade, sexo, sintomas e tempo de evolução.Resultados: Entre 51 pacientes, nove (18%) tiveram sorologia positiva para doença de Chagas e 42 (82%) sorologia negativa. Indivíduos com sorologia negativa foram considerados portadores de acalasia idiopática. Pacientes com acalasia chagásica tinham média de idade de 62 ± 15 anos e os com idiopática 43 ± 18 anos (P < 0,02). O período de evolução dos sintomas em pacientes com acalasia chagásica foi de 74 ± 47 meses e nos idiopáticos 49 ± 35 meses (P < 0,05). Disfagia, regurgitação, dor torácica e emagrecimento, valores do esfíncter esofágico inferior (pressão basal, pressão e duração de relaxamento pós-deglutição e comprimento total) e do corpo esofágico (amplitude e duração das ondas pós-deglutição) foram similares em ambos os grupos.Conclusões: As únicas diferenças estatisticamente significativas encontradas entre os dois grupos foram a média de idade e o período de evolução dos sintomas, maiores nos pacientes chagásicos. Esses dados permitem especular sobre uma maior tolerância aos sintomas nos pacientes com idade mais avançada.

Wrapping a composite material around the wall loss defective pipe is a well-known practice in pipeline rehabilitation as per guidelines provided by the design standards ISO/TS 24817 and ASME PCC-2. This work presents an analytical model to evaluate the composite repair thickness for a damaged pipeline with accounting for the plastic deformation and compare it with the results of design codes and numerical models. Hydrostatic tests performed on a repaired pipe using a composite system in different laboratories were used to validate the repair thickness using different criteria. The results show that the proposed analytical model is in good agreement with the numerical models and experimental results. The repair thickness calculated using the design codes (ISO/TS 24817 and ASME PCC-2) is more conservative, which results in repaired pipes failing outside the defect section. However, the proposed model predicts a lower composite thickness to sustain the same design pressure which enables the saving composite material. The proposed model can be refined further by accounting for the composite laminate strain using the Tsai-Hill or Hashin failure theory instead of allowable strain.

Over the last few decades, polymeric composites have been increasingly used as repair material for corroded metallic pipelines, as it can restore the loading capacity and structural integrity of a damaged pipeline. Considerable researches have been carried out on the repair of corroded metallic pipes with fiber-reinforced polymer-based composites. Also, the repair methods have been continuously improving to reduce the time and cost, and increasing the safety and operational certainty. However, there are still many issues, problems, and challenges to be overcome for effective designs. Therefore, in this article, the main developments of the composite repair system components which influence the effectiveness of the composite repair of corroded pipelines were reviewed. The properties, role, and contributions of the fiber, matrix, and putty material on the composite-repaired pipe are briefly discussed. The analytical and numerical methods for failure analysis of composite repair systems were reviewed thoroughly. Composite repair thickness determined using analytical and numerical methods has been also discussed. Finally, in the conclusion section, the current challenges and opportunities are discussed to achieve a more effective design philosophy for the composite repair of metallic pipes.

The present paper is concerned with the failure analysis of the wall loss defect in pipelines reinforced with a polymer-based composite repair system. The main goal is to propose a methodology that accounts for the pipe extremities (axial stress) in an analysis to predict an accurate failure pressure. The proposed methodology defines a simple expression for a real test specimen condition (closed-cap cylinder), which allows to estimate the failure pressure using the elastic properties of the materials and test specimen geometry. Hydrostatic tests performed in different laboratories are used to validate the proposed methodology. The results show a good agreement between the model prediction and the experimental failure pressure results in all cases. However, a careful selection of the remaining strength factor is needed, as it impacts on the accuracy and conservative level of the failure pressure. In addition to the axial stress, there is a possibility to refine the theoretical prediction of the failure pressure value by accounting for the plastic deformation far from the defect region as well as the radial stress in the failure analysis.

The Journal of Adhesion (JA) is completing 50 years dedicated to the science of adhesives and its practical applications. It was launched by Dr Lou Sharpe in 1969, a pioneer of adhesion science. Th...

A methodology of repair in pipes involving bonded joints, manufactured through the wrappage of a composite around the pipe, is becoming a common practice in the industry for a series of ass...

An increase in applications of pultruded composite material has been noted in the last decades. The material is usually employed in sectors that require high mechanical properties as well as chemical and corrosion resistance. The pultruded profiles can be joined by mechanical fasteners (i.e. bolts) or adhesive bonding. Bonded joints present many advantages, such as low weight, design flexibility and corrosion resistance. However, an inherent property of the polymers is the low superficial energy, which tends to be detrimental to the adhesion quality of the structure. In this sense, is important to perform a proper surface treatment and select an adequate adhesive. The present work investigates the influence of the adhesive type and surface treatment on the adhesion of pultruded composites. Three polyurethane adhesives and an epoxy adhesive were evaluated using tensile tests in bulk specimens. Then, the composite bonded joint was tested using single lap joints (SLJs). Two methods of mechanical abrasion were applied as surface treatment: unidirectional abrasion (UA) and bidirectional abrasion (BA). The treated samples presented rougher and more homogeneous surface profiles. Results revealed that the surface treatments improved the adhesion quality of the bonded materials compared to untreated samples. The high surface roughness produced by the BA together with a ductile adhesive resulted in the best improvement of the joint strength.

The main aim of this work is to predict the theoretical burst pressure of defective pipelines using different semi-empirical models and compare them with the results of the hydrostatic tests. A methodology was formulated with accounting for a minimum thickness (weakest section of the pipe) over the length of the pipe to predict the most conservative burst pressure. With a simple analytical expression, a reasonable accuracy and more conservative burst pressure can be obtained for any arbitrary defect shapes. A variation of burst pressure was found between theoretical prediction and hydrostatic burst test results with respect to the different semi-empirical models even for the same corroded defects. Different defect geometry shapes and pipe material conditions are the possible causes for variation in the burst pressure between the semi-empirical models, so a careful selection of these parameters is necessary. The proposed methodology predicted a more conservative burst pressure for all arbitrary defects shapes and can predict reasonably accurate values if it accounts for the axial stress.

The main aim of this work is to investigate the effect of heat treatment on the teak wood adherend bonded joints. Indian teak wood samples were kept in an oven at 150 °C for 2 h for the heat treatment process. The surface roughness values of the wood adherend before and after the heat treatment process were measured using a surface profilometer. Wettability of un-treated and heat-treated teak wood samples was determined with the contact angle measurements by using the sessile drop method. Single strap joints with un-treated and heat treated wood specimens were tested at ambient temperature. The results show that, there is a clear dependency observed in between the heat treatment and the surface roughness of the wood adherends. Wettability of teak wood adherend surface is degraded after the heat treatment process. An adverse effect of heat treatment of wood adherend on the bonding strength was observed, but the surface roughness was improved.

In this paper a theoretical analysis for determination of elastic and flexural modulus of natural fibre reinforced hybrid composite is proposed. The proposed analytical model is based on the classical lamination approach to predict the theoretical modulus. Experimental tensile and 3-point bending tests were carried out using standard specimens of inter and intra-ply hybrid composite materials. The elastic and flexural modulus predicted by the new approach showed a better agreement with the experimental results, with a maximum deviation of 11.21% and 11.65 % respectively. From the results it was observed that the theoretical value of elastic and flexural modulus was not accurately predicted by rule of hybrid mixture method. The proposed approach can be adopted as a primary tool to predict the modulus of the composite and it can also be used to optimise the composite parameters such as volume fraction of fibre, ply and fibre orientation, etc. for the maximum performance.

In this work, the water diffusion in Thermally Expandable Particles (TEPs) modified adhesives was measured and the residual strength of water saturated and desorbed TEPs-modified adhesives was assessed. Bulk specimens were used to measure the diffusion coefficient of water in a TEPs-modified adhesive and tensile dogbone specimens were used to measure the stress-strain curves as a function of water uptake. In addition, the glass transition temperature (Tg) of aged and unaged TEPs-modified adhesives was measured, and the fracture surfaces of failed tensile specimens were examined using a scanning electron microscopy (SEM). It was observed that the moisture uptake increases as a function of TEPs content. The tensile properties (i.e. strength and elastic modulus) of the TEPs-modified adhesive tend to decrease with increasing water content, which recover after desorption at the same temperature as the initial environmental conditioning.

The thermographic technique is based on the heat released during dynamic loading cycles, correlating the temperature variation on specimen's surface with the applied stress amplitude. An abrupt temperature variation under a specific stress level reveals the presence of an irreversible phenomenon inside the material, which could be associated with fatigue damage process. In this work, the fatigue performance of bonded joints is assessed by carrying out fatigue tests in a servo-hydraulic machine monitored continuously by a thermographic acquisition system, with the utilization of end notched flexure specimens composed by two steel plates of ASTM A36, bonded together with epoxy adhesive. The results confirm that the thermographic technique is quite promising as an alternative approach to estimate the bonded joint fatigue strength.

The main objective of this work was to use thermally expandable particles (TEPs) in order to create a graded adhesive along the overlap by local mixing of the particles. Different amounts o...

A rapid and reliable identification of the country of origin of protected timbers is one of the measures for combating illegal logging. Mahogany (Swietenia macrophylla King) trees are distributed from Mexico to Bolivia and the Brazilian Amazon and are included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). Near-infrared spectroscopy (NIRS) has been proven to be a promising technique for calibration based and rapid species identification. There are only a few studies concerning the origin determination of mahogany wood. The present study is dedicated to trace back mahogany wood from Bolivia, Brazil, Guatemala, Mexico and Peru by means of two different handheld NIR spectrometers. The spectra were obtained directly from the wood samples, and soft independent modeling of class analogy (SIMCA) and partial least squares for discriminant analysis (PLS-DA) models were developed for data evaluation. The SIMCA model was efficient and 67–100% and 70–98% of the origins were identified based on the spectral ranges from 1595 to 2396 nm and 950 to 1650 nm, respectively. The best results were obtained by the PLS-DA approach, in which the efficiency rates (EFR) vary from 90 to 100% with both spectrometers. In summary, both instruments were highly effective and are suitable for preliminary identification of the country of origin for mahogany wood.

The aim of the present paper is to propose a simple methodology to predict the failure pressure of wall loss defect metallic pipes reinforced with a polymer based composite repair system. 80% wall loss defects were manufactured into the pristine pipeline specimen and the failure pressure of the repaired pipeline was determined using hydrostatic tests and validated with the proposed methodology. The proposed methodology defines a simple expression which allows to estimate the failure pressure using only the elastic properties of materials. A more conservative value of failure pressure was obtained by using this methodology as compared to the ISO/TS 24817 standard. However, the failure pipe exhibited a plastic deformation at far away from the defect region, consequently this behaviour needs to be considered in the failure analysis for an accurate prediction of failure pressure.

An experimental study has been carried out to assess the adhesion quality of composite-to-metal bonded joints under salt spray ageing conditions. The tests were performed according to the ASTM standard of floating roller peel tests with a new specimen layup. The layup and geometry of the specimen was defined in order to have the Carbon Fiber Reinforced Polymer (CFRP) and carbon steel as the rigid and flexible substrate, respectively. Specimens were exposed to salt spray (or salt fog) for 30 and 90 days. The results show that the adhesion performance (i.e. average peel load) of the joints progressively decreases with increasing the ageing time. The fracture surfaces of dry specimens (non-aged) exhibit a cohesive failure within the adhesive layer, which indicates a good adhesion between the CFRP-steel interfaces. Interface degradation is indicated by a drop in peel load and adhesive failure. The percentage of adhesive failure increases with ageing times. Fracture surfaces of the adhesive failure exhibit deposition of NaCl crystal at the interface. Peel test successfully assessed the interface adhesion in aged and non-aged conditions, and can be used as a fast, easy and reliable test to study the long term durability in case of composite-metal bonded joints.

This paper proposes analytical approximations for solving extended Graetz problems with axial diffusion in infinite domains. A general formulation, valid for both parallel-plates channels and circular ducts, is employed, and a discontinuous Dirichlet condition is applied at the wall. The adopted methodology consists of transforming the 2D convection equation into simpler one-dimensional forms, using approximation rules provided by the Coupled Integral Equations Approach. This technique is employed for producing expressions for the bulk temperature, and different levels of approximations are analyzed. The results are compared with an exact analytical solution to the problem and an expression obtained with the classical lumped system analysis (CLSA). While the results obtained with the CLSA are demonstrated to be substantially discrepant compared to the exact solution, the proposed improved formulas are equivalently simple and are shown to provide very good estimates for calculating the bulk temperature distribution. In addition, estimates for the length through which heat is diffused backward are also calculated with the derived approximate formulations and a practically perfect agreement is obtained with the higher-order approximation and the exact solution data.

The James Webb Space Telescope will allow to spectroscopically study an unprecedented number of galaxies deep into the reionization era, notably by detecting [O iii]λλ4959, 5007, and H β nebular emission lines. To efficiently prepare such observations, we photometrically select a large sample of galaxies at z ∼ 8 and study their rest-frame optical emission lines. Combining data from the GOODS Re-ionization Era wide-Area Treasury from Spitzer (GREATS) survey and from HST we perform spectral energy distribution (SED) fitting, using synthetic SEDs from a large grid of photoionization models. The deep Spitzer/IRAC data combined with our models exploring a large parameter space enables to constrain the [O iii] + H β fluxes and equivalent widths for our sample, as well as the average physical properties of z ∼ 8 galaxies, such as the ionizing photon production efficiency with $\log (\xi _\mathrm{ion}/\mathrm{erg}^{-1}\mathrm{Hz})\ge 25.77$. We find a relatively tight correlation between the [O iii] + H β and UV luminosity, which we use to derive for the first time the [O iii]λλ4959, 5007 + H β luminosity function (LF) at z ∼ 8. The z ∼ 8 [O iii] + H β LF is higher at all luminosities compared to lower redshift, as opposed to the UV LF, due to an increase of the [O iii] + H β luminosity at a given UV luminosity from z ∼ 3 to z ∼ 8. Finally, using the [O iii] + H β LF, we make predictions for JWST/NIRSpec number counts of z ∼ 8 galaxies. We find that the current wide-area extragalactic legacy fields are too shallow to use JWST at maximal efficiency for z ∼ 8 spectroscopy even at 1 h depth and JWST pre-imaging to ≳30 mag will be required.

The applications of natural fibers composites are growing in many sectors such as automotive industry, furniture, packing and construction. This is mainly due to their advantages compared to synthetic fibers composites (i.e., low cost, low weight, abundant and renewable resources among others). Nowadays, all of the main international automotive manufactures use these materials and their use is expected to increase in this area. In this study, two analytical models: rule of hybrid mixtures modified (RoHM) and an analytical model based on classical lamination theory, were used to determine theoretically the elastic modulus of intra-ply natural fiber-reinforced hybrid composites. The predicted elastic modulus was compared further with the experimental elastic modulus of jute/ramie, jute/sisal and jute/curaua intra-ply hybrid composites. The prediction by the model based on classical lamination theory showed a good agreement with the experimental elastic modulus values with a maximum deviation of 10%, while the RoHM overpredicted the elastic modulus values with a maximum deviation of 44%. Other mechanical properties such as shear modulus and flexural modulus can also be predicted by the same model. The new approach presented can be adopted as a primary tool to predict the mechanical properties of intra-ply hybrid composites. However, there is still a possibility to refine the theoretical prediction of elastic modulus by accounting the curvature parameter due to interlacing of yarns in woven fabrics.

The design and qualification of composite repairs for pipelines usually requires hydrostatic tests for the determination of the failure pressure. In this work, the use of a shaft blister test to assess the failure pressure of composite repairs is proposed. Blister tests were conducted to investigate the interfacial debonding of a composite plate bonded to steel substrate. The blister test specimen represents a composite repair applied to a pipeline with a defect. The onset debonding load is used to predict the failure pressure. A 3D digital image correlation (DIC) has been used to follow up the debonding propagation and evaluate the blister shape. 3D finite element model with a cohesive zone model has been used to simulate loaded shaft blister test. A good correlation between blister tests results and finite element simulation results was obtained. The validated finite element model was used to predict failure pressure in bonded composite repaired pipes with different values of defect diameter and repair thickness. The results show that the blister test could replace hydrostatic tests for the analysis of the composite repairs performance.

Continuing interest and more developments in recent years indicated that it would be useful to update Banea and da Silva paper entitled “Adhesively bonded joints in composite materials: an overview”. This paper presents an updated review of adhesively bonded joints in composite materials, which covers articles published from 2009 to 2016. The main parameters that affect the performance of bonded joints such as surface treatment, joint configuration, geometric and material parameters, failure mode etc. are discussed. The environmental factors such as pre-bond moisture, moisture and temperature are also discussed in detail and how they affect the durability of adhesive joints. Lots of shortcomings were resolved during the last years by developing new materials, new methods and models. However, there is still a potential to evaluate and identify the best possible combination of parameters which would give the best performance of composite bonded joints.

Nowadays the use of polymeric matrix composites to repair and strengthen the damaged pipe structures in the oil industry has become a common practice. Hence, it is essential to validate the performance of new developed composite laminate materials for the damaged pipe repair. In this study, the effectiveness of a new composite laminate for the pipes repair was investigated. First, the mechanical and thermal properties of the new developed composite laminate were determined. Next, two defect types, Type A (non-through wall) and Type B (through wall) were manufactured into the pristine pipe specimen and the evaluation of the performance of the repaired pipe was carried out by hydrostatic tests. The performance of the repaired pipe using the new developed composite laminate material was satisfactory in both defect types.

In this work an innovative technique for multi-material adhesive joints debonding by combining the inductive heating method and the use of thermally expandable particles (TEPs) is presented. First, single lap joints (SLJs) using various combinations of adherends (high-strength steel (HS), aluminum (Al), and carbon fiber reinforced plastics (CFRP)) were fabricated and tested to assess the influence of TEP content on the lap-shear strength of the joints. Further, the ability of the TEP-modified joints to support temperature-controlled debonding was evaluated. It was showed that the control of debonding process by temperature is possible. The temperature needed for debonding is a function of TEP content and can be lowered by increasing the TEP content. Relatively similar debonding temperatures were found for multi-material/dissimilar joints debonding compared with similar joints, but more induction heating power is generally necessary to disassemble multi-material adhesive joints.

In this paper, a review of the test methods for bond strength of glass fiber posts to dentin is presented. The main variables that influence the bond strength tests are related to substrate, to specimen properties, specimen preparation, and test methodology. The impact of these variables on the test outcome is analyzed. The search was performed on studies published between 2007 and 2015. Most of the tests carried out, in the literature, were the push-out (75%), pull-out (13%), and microtensile (11.9%) tests, showing an inversion compared to the results found in studies published between 2005 and 2010, when push-out test was used in a proportion of 2% and microtensile test in a proportion of 67%. The push-out test emerged as a practical tool for evaluating the interfacial shear strength between fiber post and root canal walls.

We present the results of CANDELSz7, an ESO large program aimed at confirming spectroscopically a homogeneous sample of z~6 and z~7 star forming galaxies. The candidates were selected in the GOODS-South, UDS and COSMOS fields using the official CANDELS catalogs based on H160-band detections. Standard color criteria, which were tailored depending on the ancillary multi-wavelength data available for each field, were applied to select more than 160 candidate galaxies at z~6 and z~7. Deep medium resolution FORS2 spectroscopic observations were then conducted with integration times ranging from 12 to 20 hours, to reach a Lyalpha flux limit of approximately 1-3x 10-18 erg/s/cm^2 at 3sigma. For about 40% of the galaxies we could determine a spectroscopic redshift, mainly through the detection of a single emission line that we interpret as Lyalpha emission, or for some of the brightest objects (H160< 25.5) from the presence of faint continuum and sharp drop that we interpret as a Lyman break. In this paper we present the redshifts and main properties of 65 newly confirmed high redshift galaxies. Adding previous proprietary and archival data we assemble a sample of ~260 galaxies that we use to explore the evolution of the Lyalpha fraction in Lyman break galaxies and the change in the shape of the emission line between z~6 and z~7. We also discuss the accuracy of the CANDELS photometric redshifts in this redshift range., Accepted for publication in Astronomy & Astrophysics

VANDELS is a uniquely-deep spectroscopic survey of high-redshift galaxies with the VIMOS spectrograph on ESO's Very Large Telescope (VLT). The survey has obtained ultra-deep optical (0.48 < lambda < 1.0 micron) spectroscopy of ~2100 galaxies within the redshift interval 1.0 < z < 7.0, over a total area of ~0.2 sq. degrees centred on the CANDELS UDS and CDFS fields. Based on accurate photometric redshift pre-selection, 85% of the galaxies targeted by VANDELS were selected to be at z>=3. Exploiting the red sensitivity of the refurbished VIMOS spectrograph, the fundamental aim of the survey is to provide the high signal-to-noise ratio spectra necessary to measure key physical properties such as stellar population ages, masses, metallicities and outflow velocities from detailed absorption-line studies. Using integration times calculated to produce an approximately constant signal-to-noise ratio (20 < t_int < 80 hours), the VANDELS survey targeted: a) bright star-forming galaxies at 2.4 < z < 5.5, b) massive quiescent galaxies at 1.0 < z < 2.5, c) fainter star-forming galaxies at 3.0 < z < 7.0 and d) X-ray/Spitzer-selected active galactic nuclei and Herschel-detected galaxies. By targeting two extragalactic survey fields with superb multi-wavelength imaging data, VANDELS will produce a unique legacy data set for exploring the physics underpinning high-redshift galaxy evolution. In this paper we provide an overview of the VANDELS survey designed to support the science exploitation of the first ESO public data release, focusing on the scientific motivation, survey design and target selection., 19 pages, 9 figures, accepted for publication in MNRAS

Over the last two decades, the repair of existing engineering structures using fiber reinforced polymer composites has attracted a great attention by aerospace industry, as it is more economical than replacing new. With an increased use of composite material in aerospace field, it is thus essential to restore the structural integrity by repair of damaged part. Concerns regarding the long term durability of composite repair bonded joints have been a major obstacle for critical component of aerospace structures. This paper reviews the current research on the environmental durability of adhesive bonded repair of composite structures to focus on the durability concerns and suggestion on the research needed in this area. The most important environmental factors (moisture and temperature) are reviewed thoroughly and also combined environmental effect. Finite element methods used to predict the environmental influence on the composite bonded joints are briefly reviewed. Finally, the paper concludes with key findings, opportunities and future research topics in order to develop cost effective, better quality and reliable composite repair bonded joints.

Adhesively bonded joints can support a longer fatigue life if compared to conventional joining techniques, provided that a set of requirements is fulfilled. One of the most important requirements is the mechanical preparation of the bonded joint surface, which improves the joint interface adhesion. The aim of this work is to investigate the influence of surface roughness of mild steel substrates on fatigue behavior in adhesive bonded plates. To accomplish this objective, three different surface treatments were used on A36 steel substrate specimens, namely sand blasting, grit blasting, and bristle blasting. Bonded plate specimens, using end-notched flexure format, with a thin adhesive epoxy layer were manufactured and tested, under mode II loading condition, in both static and dynamic tests. The results confirm the importance of surface treatment of the substrate on the fatigue life, confirming that adhesively bonded joints have significant performance differences when subjected to static and dynam...

We investigate the morphology of the [CII] emission in a sample of "normal" star-forming galaxies at $5, Comment: 14 pages, 11 figure, 3 tables, submitted to MNRAS journal

In this work, an experimental study has been carried out to evaluate the effect of salt water condition on the long-term adhesion of composite-to-metal bonded joints using peel tests. A new test configuration is tested via fully and partially immersed specimens with 500 mm length. Fracture surfaces of non-aged samples exhibited a cohesive failure within the adhesive layer, which indicates a good adhesion of the joint. Results revealed a significant difference in the interface adhesion between aged and non-aged condition after 150 days of immersion. Partially immersed specimens allow to evaluate the adhesion performance of the joint under dry and wet condition in single specimen using a simple peel test.

The assessment of networks is frequently accomplished by using time-consuming analysis tools based on simulations. For example, the blocking probability of networks can be estimated by Monte Carlo simulations and the network resilience can be assessed by link or node failure simulations. We propose in this paper to use Artificial Neural Networks (ANN) to predict the robustness of networks based on simple topological metrics to avoid time-consuming failure simulations. We accomplish the training process using supervised learning based on a historical database of networks. We compare the results of our proposal with the outcome provided by targeted and random failures simulations. We show that our approach is faster than failure simulators and the ANN can mimic the same robustness evaluation provide by these simulators. We obtained an average speedup of 300 times.

Gel beads were prepared by extrusion of various types of pectin into 0.15 M calcium chloride. Size, morphology, and textural properties of 3 types of beads were evaluated and it was established that the use of 3 w/v % amidated pectin provides the optimal characteristics suitable for encapsulation of live bacteria. Lactobacillus casei NCIMB 30185 (PXN37) was encapsulated into calcium pectinate gel through the extrusion of a live bacteria dispersion in 3 w/v % pectin into a solution of calcium chloride. The capsules were then additionally coated with chitosan. The viability of bacteria within these capsules was studied under model gastrointestinal conditions in vitro (simulated gastric and intestinal juices). It was established that pectin-chitosan capsules can provide protection to L. casei from the gastric acid and result in high levels of viable bacteria released in the intestine.Encapsulation of Lactobacillus casei into calcium pectinate beads coated with chitosan provided capsules capable of delivering live probiotic bacteria into the intestine.

We study the spectrophotometric properties of a highly magnified (\mu~40-70) pair of stellar systems identified at z=3.2222 behind the Hubble Frontier Field galaxy cluster MACS~J0416. Five multiple images (out of six) have been spectroscopically confirmed by means of VLT/MUSE and VLT/X-Shooter observations. Each image includes two faint (m_uv~30.6), young (50000 K) stars within dense stellar clusters, whose dynamical mass is likely dominated by the stellar component. Remarkably, the ultraviolet metal lines are not accompanied by Lya emission (e.g., CIV / Lya > 15), despite the fact that the Lya line flux is expected to be 150 times brighter (inferred from the Hbeta flux). A spatially-offset, strongly-magnified (\mu>50) Lya emission with a spatial extent 34 de-lensed). This is the first confirmed metal-line emitter at such low-luminosity and redshift without Lya emission, suggesting that, at least in some cases, a non-uniform covering factor of the neutral gas might hamper the Lya detection., Comment: 11 pages, 9 figures, 2 Tables. ApJ Accepted

Quasicrystals (QC) are materials that exhibit good surface properties such as high hardness, low surface energy, low friction coefficient, and good resistance to oxidation and corrosion. Despite these properties, QC alloys are highly brittle, discouraging their uses in applications requiring mechanical stresses. Hence, the development of composites using quasicrystalline materials as reinforcement to ductile matrices is an interesting alternative. In this work, Al-Cu-Fe quasicrystals were used as a reinforcement to epoxy resin in order improve adhesion with metallic substrates. Adhesive properties were evaluated by single lap joint (SLJ) tests and the QC/epoxy interface was analyzed by scanning electron microscopy (SEM). Aluminum, copper, and iron, individual elements, were used to investigate the contribution of each element to the adhesive. Results show that it was possible to significantly enhance adhesion properties when 25% QC was added to epoxy and that the effect of QC amount on SLJ bond strength d...