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Scour is a phenomenon that affects structures deployed in rivers or seas, favoring the transport of sediments around their foundations, which can expose their structural stability. This work aimed to develop a physical model of a mobile bottom to determine the scour-hole extensions around a group of four vertical piles of circular sections subjected to irregular waves. For this purpose, a beach profile and a typical slope were constructed and subjected to 24 h of storm waves, divided into 12 h intervals in the prototype. Additionally, three wave periods were studied according to the Mexican Institute of Transportation wave data and three scenarios of a rise in sea level. The data suggest that the length of the scour hole was greater in the piles in the front for all cases, which may be reflected in a reduction in scour protection costs. The results obtained for the extent of the scour hole suggest a setting of less than four times the pile diameter in most cases. Finally, it is inferred that a rise in sea level by itself is not a decisive factor in the increase in the values obtained; therefore, it is necessary to consider the variations in wave heights and wave periods associated with such increases.

A porous-solid model based on the grain and pore size distributions of the soil is coupled with a mechanical model to simulate the soil-water retention curves while the material is deforming. During the determination of the main drying curve, the soil is subjected to high suctions which induce important volumetric deformations. These volumetric deformations modify the pore size distribution of the sample affecting both the drying and the wetting retention curves. Although, most deformation occurs at drying, the drying curve is only slightly affected by soil deformation. In contrast, the wetting curve shows important shifting when volume change is considered.

Soil’s consolidation is a geotechnical problem resulting from a stress-transfer process that initiates when the load is applied to the water contained in the soil, producing a reduction in pore water pressure and rearranging the solid particles, and thus causing a decrease in soil volume. Therefore, consolidation is a coupled flow–mechanical problem. Coupled models have been developed to simulate this phenomenon while considering different theories, providing consistent results. This paper presents an elastoplastic coupled model of consolidation under Terzaghi’s effective stress formulated using the equations of transient flow, balance moment, motion, and the critical state model that considered elastoplastic strains. The coupled model algorithm provided fast and easy results due to its flexibility, as it allowed combinations in loading and boundary conditions. Additionally, it considered the external/internal water flow as an inflow or outflow, which modified the pore water pressure and produced changes in the horizontal and vertical displacements. The numerical results obtained showed an appropriate behavior of the consolidation phenomenon, as well as the evolution of the vertical Uy and horizontal Ux displacements, water pressure pw, volumetric εv and deviatoric εq strain, mean σp and deviatoric σq stress, volumetric variation ∆εv, and elastic/plastic behavior of the finite elements while considering the yield surface of the critical state.

The Trans-Mexican Volcanic Belt (TMVB), located in central Mexico, is an area for which low to moderate seismic risk is considered. This is based on the limited instrumental data available, even though large historical earthquakes have damaged some urban centers in the past. However, site effects is an aspect that must be considered in estimating risk, because there are some instances of important amplifications that have been documented with serious effects. In this work, ambient noise and earthquake records from 90 seismic permanent and temporary stations are used to analyze site response in the TMVB. The results obtained show a heterogeneous range in the value of the fundamental frequency. When possible, a comparison was made of the results obtained from ambient noise and earthquake records. In almost all these comparisons, no significant differences were observed in terms of the fundamental frequency. However, there were some stations with a flat average HVSR ambient noise curve that contradicted earthquake data results, which showed peaks at some frequencies. Our results are a first step towards categorizing the different site responses in the TMVB but in order to provide finer details, it is necessary to improve the actual monitoring conditions.

The settlements produced by the load transmitted to the structure on expansive soils, and those calculated by the classical theories of soil mechanics, are different because the swelling pressure acts inversely to the applied stress. In this paper we describe a procedure to determine a volumetric variation coefficient by hydration (αh) which considers the expansive soil behaviour. In order to do this, it is necessary to know the soil’s initial water content, the swelling pressure, and the applied stress. Soil suction and swelling pressure were measured with filter paper technique and a mechanical oedometer, respectively. Unsaturated undisturbed samples of expansive soil were used. The water content was varied, starting from 0%, with increments of 5.5% to reach 38%. Furthermore, we present a set of curves that show the magnitude of the coefficient (αh) associated to a water content, and the relationship between applied stress and swelling pressure. The results show that the variation of the coefficient under different initial water contents ranges between 0% to 22%. This is because water is strongly attracted by clay minerals, but this attraction decreases as water layers are father from the surface of clay minerals, thus decreasing its swelling potential.

One of the best indicators for construction sustainability is the use of earthy local materials which are completely recyclables and savers of energy during their life cycle. Tepetate is an underestimated earth-natural material, vast and economic, used only in a compacted form in backfills for layers of low resistance in pavements and platforms of buildings. This volcanic soil, named in different ways in several countries, is found in the central region of Mexico. Its resistance as compacted material is very low, of the order of 0.08 MPa. In this work, an improved sustainable-tepetate composite, using CaOH, is presented. This research includes the determination of mechanical properties as well as the physicochemical characterization of the sustainable-tepetate composite behavior. It can be concluded that the strength of the proposed composite increases significantly, immediately after treatment and with time. X-Ray Diffraction shows that all the mineralogical phases prevail in the natural tepetate and only a new phase appeared (calcite), which increases with time. This and the reaction of CaOH with clay content are very likely associated with the continuous strength increase of the composite.

Implanting sutureless aortic valves enables a reduction in surgical times and related complications. Nonetheless, their application has been limited in cases involving aortic aneurysms due to anchor system concerns. We present a case of aortic valve replacement using a Perceval™ sutureless aortic valve in a patient with stage IV chronic kidney disease, an ascending aortic aneurysm, and a porcelain aorta. The procedure was performed concomitantly with coronary artery bypass grafting involving two grafts, as well as ascending aorta and hemiarch replacement. This case underscores the critical importance of time efficiency, technical modifications for valve implantation, and strategic surgical planning to mitigate potential intraoperative and postoperative complications.

Cellular concrete bricks were obtained by using a lightweight mortar with recycled expanded polystyrene aggregate instead of sandy materials. After determining the block properties (absorption, compressive strength, and tensile stresses), it was found that this brick meets the requirements of the masonry standards used in Mexico. The obtained material is lighter than the commercial ones, which facilitates their rapid elaboration, quality control, and transportation. It is less permeable, which helps prevent moisture formation retaining its strength due to the greater adherence shown with dry polystyrene. It was more flexible, which makes it less vulnerable to cracking walls due to soil displacements. Furthermore, it is economical, because it uses recyclable material and has properties that prevent deterioration increasing its useful life. We recommend the use of the fully dry EP under a dry environment to obtain the best properties of brick.

Background Psychological treatments have been successful in treating chronic low back pain (CLBP). However, the effect sizes are still modest and there is room for improvement. A way to progress is by enhancing treatment adherence and self-management using information and communication technologies (ICTs). Therefore, the objective of this study was to design a trial investigating the short- and long-term efficacy of cognitive behavioural treatment (CBT) for CLBP using or not ICTs. A secondary objective of this trial will be to evaluate the influence of relevant variables on treatment response. Possible barriers in the implementation of CBT with and without ICT will also be investigated. Methods A randomised controlled trial with 180 CLBP patients recruited from specialised care will be conducted. Participants will be randomly assigned to three conditions: Control group (CG), CBT, and CBT supported by ICTs (CBT + ICT). Participants belonging to the three conditions will receive a conventional rehabilitation program (back school). The CBT group program will last six sessions. The CBT + ICT group will use the internet and SMS to practice the therapeutic strategies between sessions and in the follow-ups at their homes. Primary outcome variables will be self-reported disability and pain intensity. Assessment will be carried out by blinded assessors in five moments: pre-treatment, post-treatment and 3-, 6-, and 12-month follow-ups. The influence of catastrophizing, fear-avoidance beliefs, anxiety and depression in response to treatment in the primary outcomes will also be analysed. Discussion This study will show data of the possible benefits of using ICTs in the improvement of CBT for treating CLBP. Trial registration ClinicalTrials.gov, NCT01802671

To date, there have been reported several quality factors Q(f) = Q0fα in the literature for the Trans-Mexican Volcanic Belt (TMVB), with significant variations between them. Most of these studies do not fully specify the parameters used in their analyses or they rely on seismograms of earthquakes whose epicenter lies outside the study zone. In this paper, quality factors were determined for the TMVB from the analysis of coda waves. For this purpose, there were used local records related to earthquakes with the epicenter lying inside the TMVB. A division of the study area is considered according to the geological characteristics, and a correlation with the coda Q(f) values was obtained. Results show a clear dependenceof Q(f) on the characteristics and location of the source. Important variations were identified in comparison with studies that report Q(f) values for the TMVB using different methodologies and source characteristics.