Effect of welding orientation in angular distortion in multipass GMAW

The use of the welding process on an industrial scale has become significant over the years and is currently among the main processes for joining metallic materials. Along the weld, structural changes occur in the vicinity of the joint. These thermal stresses and geometric distortions are mostly undesirable and are complex to predict with precision. Using S235JR steel as the base material, laboratory experiments were carried out using the multipass GMAW process, with the aim of investigating the influence of the welding direction on angular distortion. To measure the distortions, a methodology was applied using equipment to identify the coordinates in the operational space with metrological precision. Through metrological and statistical analyses, we found that the orientation factor significantly influenced the final distortions and that the alternated orientation sequence resulted in less distortions.This work has been supported by FCT—Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: CIMO (UIDB/00690/2020).info:eu-repo/semantics/publishedVersio

A Review of Methods to Modify the PDMS Surface Wettability and Their Applications

Polydimethylsiloxane (PDMS) has attracted great attention in various fields due to its excellent properties, but its inherent hydrophobicity presents challenges in many applications that require controlled wettability. The purpose of this review is to provide a comprehensive overview of some key strategies for modifying the wettability of PDMS surfaces by providing the main traditional methods for this modification and the results of altering the contact angle and other characteristics associated with this property. Four main technologies are discussed, namely, oxygen plasma treatment, surfactant addition, UV-ozone treatment, and the incorporation of nanomaterials, as these traditional methods are commonly selected due to the greater availability of information, their lower complexity compared to the new techniques, and the lower cost associated with them. Oxygen plasma treatment is a widely used method for improving the hydrophilicity of PDMS surfaces by introducing polar functional groups through oxidation reactions. The addition of surfactants provides a versatile method for altering the wettability of PDMS, where the selection and concentration of the surfactant play an important role in achieving the desired surface properties. UV-ozone treatment is an effective method for increasing the surface energy of PDMS, inducing oxidation, and generating hydrophilic functional groups. Furthermore, the incorporation of nanomaterials into PDMS matrices represents a promising route for modifying wettability, providing adjustable surface properties through controlled dispersion and interfacial interactions. The synergistic effect of nanomaterials, such as nanoparticles and nanotubes, helps to improve wetting behaviour and surface energy. The present review discusses recent advances of each technique and highlights their underlying mechanisms, advantages, and limitations. Additionally, promising trends and future prospects for surface modification of PDMS are discussed, and the importance of tailoring wettability for applications ranging from microfluidics to biomedical devices is highlighted. Traditional methods are often chosen to modify the wettability of the PDMS surface because they have more information available in the literature, are less complex than new techniques, and are also less expensive.Financial support was provided by Portugal's national funding FCT/MCTES (PIDDAC) to Centro de Investigacao de Montanha (CIMO) (UIDB/00690/2020 and UIDP/00690/2020) and SusTEC (LA/P/0007/2020). The authors additionally acknowledge the projects 2022.02085.PTDC (https://doi.org/10.54499/2022.02085.PTDC), 2022.06207.PTDC(https://doi.org/10.54499/2022.06207.PTDC), and PTDC/EEI-EEE/2846/2021 (https://doi.org/10.54499/PTDC/EEI-EEE/2846/2021) for financial support through national funds (OE), within the scope of the Scientific Research and Technological Development Projects (IC&DT) program in all scientific domains (PTDC); the PORTUGAL 2020 Partnership Agreement, European Regional Development Fund (FEDER), via the Foundation for Science and Technology; and I.P. (FCT, I.P) and the R&D Units projects, UIDB/04077/2020, UIDB/00532/2020, and LA/P/0045/2020 (ALiCE). Glauco Nobrega was supported by the doctoral grant PRT/BD/153088/2021 financed by the Portuguese Foundation for Science and Technology (FCT) under the MIT Portugal Program.info:eu-repo/semantics/publishedVersio

Higher physical fitness levels are associated with less language decline in healthy ageing

publishedVersio

The use of barriers to limit the spread of aquatic invasive animal species: a global review

Aquatic invasive species (AIS) are one of the principal threats to freshwater biodiversity. Exclusion barriers are increasingly being used as a management strategy to control the spread of AIS. However, exclusion barriers can also impact native organisms and their effectiveness is likely to be context dependent. We conducted a quantitative literature review to evaluate the use of barriers to control animal AIS in freshwater ecosystems worldwide. The quantitative aspect of the review was supplemented by case studies that describe some of the challenges, successes, and opportunities for the use of the use of AIS exclusion barriers globally. Barriers have been used since the 1950s to control the spread of AIS, but effort has been increasing since 2005 (80% of studies) and an increasingly diverse range of AIS taxa are now targeted in a wide range of habitat types. The global use of AIS barriers has been concentrated in North America (74% of studies), Australasia (11%), and Europe (10%). Physical barriers (e.g., weirs, exclusion screens, and velocity barriers) have been most widely used (47%), followed by electric (27%) and chemical barriers (12%). Fish were the most targeted taxa (86%), followed by crustaceans (10%), molluscs (3%) and amphibians (1%). Most studies have been moderately successful in limiting the passage of AIS, with 86% of the barriers tested deterring >70% of individuals. However, only 25% of studies evaluated barrier impacts on native species, and development of selective passage is still in its infancy. Most studies have been too short (47% < 1 year, 87% < 5 years) to detect ecological impacts or have failed to use robust before-after-control-impact (BACI) study designs (only 5%). Hence, more effective monitoring is required to assess the long-term effectiveness of exclusion barriers as an AIS management tool. Our global case studies highlight the pressing need for AIS control in many ecoregions, and exclusion barriers have the potential to become an effective tool in some situations. However, the design and operation of exclusion barriers must be refined to deliver selective passage of native fauna, and exclusion barriers should only be used sparingly as part of a wider integrated management strategy

Estado actual de la programación del riego en limero mediante medidas del estado hídrico

: En el presente trabajo se realiza una revisi´on sobre aspectos relativos a la utilizaci´on de medidas continuas del estado h´ıdrico del limonero en la programaci´on del riego. Para ello, se analiz´o, la sensibilidad de distintos indicadores del estado h´ıdrico medidos de forma continua o discontinua en las plantas, su significado fisiol´ogico, la obtenci´on de niveles de referencia de los indicadores y los primeros resultados sobre programaci´on del riego

The UKIDSS Galactic Plane Survey

'The definitive version is available at www.blackwell-synergy.com .' Copyright Blackwell Publishing DOI: 10.1111/j.1365-2966.2008.13924.xThe UKIDSS Galactic Plane Survey (GPS) is one of the five near-infrared Public Legacy Surveys that are being undertaken by the UKIDSS consortium, using the Wide Field Camera on the United Kingdom Infrared TelescopePeer reviewe

SUSY GUT Model Building

I discuss an evolution of SUSY GUT model building, starting with the construction of 4d GUTs, to orbifold GUTs and finally to orbifold GUTs within the heterotic string. This evolution is an attempt to obtain realistic string models, perhaps relevant for the LHC. This review is in memory of the sudden loss of Julius Wess, a leader in the field, who will be sorely missed.Comment: 24 pages, 14 figures, lectures given at PiTP 2008, Institute for Advanced Study, Princeton, to be published in the European Physical Journal

Tradeoffs and synergies in wetland multifunctionality: A scaling issue

Wetland area in agricultural landscapes has been heavily reduced to gain land for crop production, but in recent years there is increased societal recognition of the negative consequences from wetland loss on nutrient retention, biodiversity and a range of other benefits to humans. The current trend is therefore to re-establish wetlands, often with an aim to achieve the simultaneous delivery of multiple ecosystem services, i.e., multifunctionality. Here we review the literature on key objectives used to motivate wetland re-establishment in temperate agricultural landscapes (provision of flow regulation, nutrient retention, climate mitigation, biodiversity conservation and cultural ecosystem services), and their relationships to environmental properties, in order to identify potential for tradeoffs and synergies concerning the development of multifunctional wetlands. Through this process, we find that there is a need for a change in scale from a focus on single wetlands to wetlandscapes (multiple neighboring wetlands including their catchments and surrounding landscape features) if multiple societal and environmental goals are to be achieved. Finally, we discuss the key factors to be considered when planning for re-establishment of wetlands that can support achievement of a wide range of objectives at the landscape scale

Chemoreceptor responsiveness at sea level does not predict the pulmonary pressure response to high altitude

The hypoxic ventilatory response (HVR) at sea level (SL) is moderately predictive of the change in pulmonary artery systolic pressure (PASP) to acute normobaric hypoxia. However, because of progressive changes in the chemoreflex control of breathing and acid-base balance at high altitude (HA), HVR at SL may not predict PASP at HA. We hypothesized that resting peripheral oxyhemoglobin saturation (SpO2) at HA would correlate better than HVR at SL to PASP at HA. In 20 participants at SL, we measured normobaric, isocapnic HVR (L/min·-%SpO2 -1) and resting PASP using echocardiography. Both resting SpO2 and PASP measures were repeated on day 2 (n=10), days 4-8 (n=12), and 2-3 weeks (n=8) after arrival at 5050m. These data were also collected at 5050m on life-long HA residents (Sherpa; n=21). Compared to SL, SpO2 decreased from 98.6 to 80.5% (P<0.001), while PASP increased from 21.7 to 34.0mmHg (P<0.001) after 2-3 weeks at 5050m. Isocapnic HVR at SL was not related to SpO2 or PASP at any time point at 5050m (all P>0.05). Sherpa had lower PASP (P<0.01) than lowlanders on days 4-8 despite similar SpO2. Upon correction for hematocrit, Sherpa PASP was not different from lowlanders at SL, but lower than lowlanders at all HA time points. At 5050m, whilst SpO2 was not related to PASP in lowlanders at any point (all R2=0.50), there was a weak relationship in the Sherpa (R2=0.16; P=0.07). We conclude that neither HVR at SL nor resting SpO2 at HA correlates with elevations in PASP at HA