González Lezcano, Roberto Alonso

A cataract is defined as opacity of the crystalline lens. It is currently one of the most prevalent ocular pathologies and is generally associated with aging. The most common treatment for cataracts is surgery. Cataract surgery is a quick and painless process, is very effective, and has few risks. The operation consists of removing the opacified lens and replacing it with an intraocular lens. The most common intraocular lens removal procedure that is currently used is phacoemulsification. The energy applied in this process is generated by ultrasonic waves, which are mechanical waves with a frequency higher than 20 kHz. A great deal of research on the different ways to perform the stages of this surgical procedure and the analysis of the possible side effects of the operation has been published, but there is little information on the technical characteristics, the intensities applied, and the use of ultrasound-emitting (U/S) equipment for cataract removal. More studies on the method and depth of absorption of ultrasonic waves in our visual system when performing the phacoemulsification procedure are needed. It would be advisable for health authorities and medical professionals to develop guidelines for the handling and use of ultrasonic wave-emitting equipment, such as those that exist for ultrasound and physiotherapy. This could help us to reduce undesirable effects after the operation.

The Passive House (PH) concept is considered an e cient strategy to reduce energy consumption in the building sector, where most of the energy is used for heating and cooling applications. For this reason, energy e ciency measures are increasingly implemented in the residential sector, which is the main responsible for such a consumption. The need for professionals dealing with energy issues, and particularly for architects during the early stages of their architectural design, is crucial when considering energy e cient buildings. Therefore, architects involved in the design and construction stages have key roles in the process of enhancing energy e ciency in buildings. This research work explores the energy e ciency and optimized architectural design for residential buildings located in di erent climate zones in Spain, with an emphasis on Building Performance Simulation (BPS) as the key tool for architects and other professionals. According to a parametric analysis performed using Design Builder, the following optimal configurations are found for typical residential building projects: North-to-South orientation in all the five climate zones, a maximum shape factor of 0.48, external walls complying with the maximum U-value prescribed by Spanish Building Technical Code (0.35 Wm􀀀2K􀀀1) and a Window-to-Wall Ratio of no more than 20%. In terms of solar reflectance, it is found that the use of light colors is better in hotter climate zones A4, B4, and C4, whereas the best option is using darker colors in the colder climate zones D3 and E1. These measures help reaching the energy demand thresholds set by the Passivhaus Standard in all climate zones except for those located in climates C4, D3 and E1, for which further passive design measures are needed.

Unlike conventional concrete materials, Engineered Cementitious Composites (ECC) use a micromechanics-based design theory in the material design process. Recently, the use of nanoparticles in various concretes and mortars has increased. This study used nanocalcite to investigate the mechanical, microstructural fractal analysis of environmentally friendly nanocalcite-doped ECC (NCa-ECC). This paper investigated the effects of nanocalcite (NCa) with different contents (0.5, 1, and 1.5% by mass of binder) on the mechanical properties of engineered cementitious composites (ECC). For this purpose, compressive strength, ultrasonic pulse velocity (UPV), and flexural strength tests were conducted to investigate the mechanical properties of the ECC series. In addition, SEM analyses were carried out to investigate the microstructural properties of the ECC series. The content of nanocalcite improved the mechanical and microstructural properties of the nanocalcite-modified ECC series. In addition, the 1 NCa series (1% nanocalcite modified to the mass of the binder) had the best performance among the series used in this study.

The existence of a growing myopia pandemic is an unquestionable fact for health authorities around the world. Different possible causes have been put forward over the years, such as a possible genetic origin, the current excess of children’s close-up work compared to previous stages in history, insufficient natural light, or a multifactorial cause. Scientists are looking for different possible solutions to alleviate it, such as a reduction of time or a greater distance for children’s work, the use of drugs, optometric correction methods, surgical procedures, and spending more time outdoors. There is a growing number of articles suggesting insufficient natural light as a possible cause of the increasing levels of childhood myopia around the globe. Technological progress in the world of lighting is making it possible to have more monochromatic LED emission peaks, and because of this, it is possible to create spectral distributions of visible light that increasingly resemble natural light in the visible range. The possibility of creating indoor luminaires that emit throughout the visible spectrum from purple to infrared can now be a reality that could offer a new avenue of research to fight this pandemic.

Recently, studies on sustainability and ecology have become widespread in almost all sectors. One of the most important reasons for this spread is the rapid increase in industrialization and, thus, the increase in waste caused by industries. In this context, significant efforts are being made to evaluate some of these wastes. One of these efforts is the production of geopolymers. In this research, metakaolin and slag-based geopolymer mortar samples were manufactured, and polyvinyl Alcohol, basalt, and macro synthetic polypropylene fibers were used to enhance the physical, mechanical, and high-temperature resistance of the sample. Physical and mechanical tests of the produced samples were performed after 28 days. Then, elevated-temperature experiments were conducted to evaluate the behavior of the fibers under the influence of high temperature. Following the high-temperature test, physical, mechanical and microstructure tests of the samples were performed. As a result, basalt fiber enhanced the compressive strength of 800 ◦C-exposed samples by 7.72% compared to the fiber-free sample. Also, polyvinyl Alcohol fiber increased the energy absorption capacity of the samples by increasing Charpy impact values to 72.22% compared to fiber-free sample. Moreover, macro synthetic polypropylene fiber reduced capillary water absorption value up to 12.44% compared to fiber-free sample.

This article discusses the influence of the dimensions of the damping rings used for interrupting a dynamic tension experiment on the results of a modified split Hopkinson tension bar. The damping rings enclosed in an external fixture which modifies the classical split Hopkinson tension bar play a significant role in buffering the dynamic tension experiments before the specimen reaches its failure strength. Finite element simulations of high-strain-rate tension experiments are accomplished on Aluminium 7017-T73 alloy specimens when varying the thickness or the cross-sectional area of the damping rings. Finite element analyses described herein are applied to simulate the effects of the variation of the damping rings’ dimensions to provide a reference for improvement of a modified split Hopkinson tension bar experimental apparatus and guidance for future studies in which optimum dimensions for the damping rings can be studied. In view of this research, it can be concluded that the thickness of the damping rings is a factor that can resolutely influence the interrupted dynamic tension experiment results, while their cross-sectional area can be excluded as a factor influencing the results of the modified split Hopkinson tension bar experiments.

The scientific understanding of the concepts of cold and heat that have accompanied the human species throughout history has not been easy. The concept of heat is more widespread and studied among us, as well as its consequences. However, we wonder what would happen if we lowered the temperature a lot? As the temperature begins to drop, it can be predicted that the atoms tend to slow down, slowing down their speed, and when this happens, existing theories begin to tremble. The laws governing the atomic world, so small and tiny, do not allow objects (atoms, protons, neutrons, etc.) to stop. This is where quantum physics appears, it tells us how particles behave at the atomic level, and they appear in a forceful way when we approach temperature values around absolute zero. If atoms stopped moving, they would have zero energy, however, quantum mechanics makes it impossible to have this kind of energy.