Newest Updates in Physical Science Research Vol. 8

Distributions of the universe horizon distance and universe horizon volume were investigated in the light of five general cosmic models which were constructed in a previous study. Both distributions increase so slowly up to t \(\approx\) 21.5444 Myr, , then they start rising very fast up to t \(\approx\) 60 Gyr. Afterwards, they increase again very slowly until t \(\approx\) 124 Gyr. Distributions of mass of radiation, matter and dark energy within the horizon volume of the universe were also studied in the five general cosmic models. The masses of both radiation and matter decrease gradually with time to t \(\approx\) 34627.5 – 55916.2 yr, where it becomes equal to the mass of matter. Then the mass of matter dominated until t \(\approx\) 9.4525 – 10.0632 Gyr, where it becomes equal to the mass of dark energy. Thenceforward, the mass of dark energy prevails the universe. The cosmic space becomes approximately matter empty in the so far future of the universe.

The universe’s horizon distance and volume are constructed in the closed cosmic model. The universe horizon distance distribution increases constantly for t < t_me and decreases for t > t_me . However, the universe’s horizon volume shows a sudden reduction in the range t = 0.5 Gyr - tme due to the change of the universe space from flat to curved then closed in the interval 15.1261 Gyr \(\leq\) t \(\leq\) t_me. On the other hand, this distribution exhibits an abrupt rise in the range t = t_me - t* due to the change of the universe space from closed then curved to flat in the interval 39.3822 \(\leq\) t \(\leq\) 40.7521 Gyr. The distributions of mass of radiation, matter and dark energy within the horizon volume of the universe are also investigated. These distributions reveal similar noticeable changes as the universe’s horizon volume distribution for the same reasons. The mass of radiation dominates up to t = 53221.5 yr, then the mass of matter becomes larger. Afterwards, both distributions of radiation and matter decrease while the distribution of dark energy rises until t = 10.1007 Gyr, where the mass of dark energy prevails up to t = t_me. Hence, the distribution of dark energy descends until t = 40.2892 Gyr, where the mass of matter becomes prominent again. At t = 53.6246 Gyr the masses of both matter and radiation become appreciably high such that the intercluster space will vanish and clusters of galaxies interfere with each other. Furthermore, not only the intergalactic medium will disappear, but also galaxies will collide and merge with each other to form extremely dense and close cosmological bodies. These very dense bodies will undergo further successive collisions and mergers under the action of central gravity, where the interstellar medium will vanish and the universe would develop to big crunch at tbc = 53.6251 Gyr. It is interesting to note that the horizon distance of the universe in the closed model at t = t_me is in very good agreement with the maximum horizon distances in the five general cosmic models.

The progress of student learning in a learning process has not been fully optimally observed by the teacher. The concept being taught is judged only at the end of learning as a product of thinking and does not assess the mental processes that occur in students' thinking. Facilitating students' thinking through new phenomena can reveal students' variation in thinking as a mental model of a concept so that students who are assimilative and or accommodative can be identified in achieving their equilibrium of thought as well as an indicator of progressivity in the students' thinking stages. The aim of this study is to mapping the student’s learning progression based on mental models in the magnetic induction concept. This research data is obtained from the written documents and interviews of students who were learned about the concept of magnetic induction through the Constructivist Teaching Sequences (CTS) model. The results of this study indicate that facilitating the students' thinking processes on the concept of magnetic induction contributes to increasing the number of students thinking within the "progressive change" category to be more dominant (76%). In addition, there are also 12% of students who think in the category "change more randomly ", 8% of students are consistent with the basis of the analogy of thinking, and only 4% are consistent in the scientific concepts they understand since the beginning of learning. Thus, it can be said that the progress of student learning is more progressive after the ideas are facilitated through new phenomena by teachers.

The dynamics and evolution of a coastal sandy system over the last 142 years (1875–2017) were analyzed using geomatics techniques (historical cartography, photogrammetry, topography, and terrestrial laser scanning (TLS)). The continuous beach–dune system is a very active confining sand barrier closing an estuarine system where damage is suffered by coastal infrastructures and houses. The techniques used and documentary sources involved historical cartography, digitalizing the 5-m-level curve on the maps of 1875, 1908, 1920, 1950, and 1985; photogrammetric flights of 1985, 1988, and 2001 without calibration certificates, digitalizing only the upper part of the sandy front; photogrammetric flights of 2005, 2007, 2010, and 2014, using photogrammetric restitution of the 5-m-level curve; topo-bathymetric profiles made monthly between 1988 and 1993 using a total station; a terrestrial laser scanner (TLS) since 2011 by means of two annual measurements; and the meteorological data for the period of 1985–2017. The retreat of the sandy complex was caused by winter storms with large waves and swells higher than 6 m, coinciding with periods demonstrating a high tidal range of over 100 and periods with a large number of strong storms. The retreat was 8 m between December 2013 and March 2014. The overall change of the coastline between 1875 and 2017 was approximately 415 m of retreat at Somo Beach. The erosive processes on the foredune involved the outcrop of the rock cliff in 1999 and 2014, which became a continuous rocky cliff without sands. To know the recent coastal evolution and its consequences on the human environment, the combined geomatic techniques and future TLS data series may lead to the improvement in the knowledge of shoreline changes in the context of sea level and global changes. The combination and complementarities of different techniques and sources, such as historical cartography, photogrammetric flight series, and TLS, were very useful to know the evolution and erosive rhythms on the foredune.

The beaches of the Cantabrian coast (northern Spain) are exposed to strong winter storms, which cause the coastline to recede. In this chapter, the coastal retreat of the Gerra beach (Cantabria) is analyzed through a diachronic study using the following different geomatic techniques: orthophotography of the year 1956; photogrammetric flights from 2001, 2005, 2010, 2014, 2017; Light Detection and Ranging (LiDAR) survey from August 2012; Unmanned Aerial Vehicle (UAV) survey from November 2018; and terrestrial laser scanner (TLS) through two dates per year (spring and fall) from April 2012 to April 2020. With the 17 observations of TLS, differences in volume of the beach and the sea cliff are determined during the winter (November–April) and summer (May–October) periods, searching their relationship with the storms in this eight-year period (2012–2020). From the results of this investigation it can be concluded that the retreat of the base of the cliff is insignificant, but this is not the case for the top of the cliff and for the existing beaches in the Cantabrian Sea where the retreat is evident. The retreat of the cliff top line in Gerra beach, between 1956 and 2020 has shown values greater than 40 m. The retreat in other beaches of the Cantabrian Sea, in the same period, has been more than 200 m. With our measurements, investigations carried out on the retreat of the cliffs on the Atlantic coast have been reinforced, where the diversity of the cliff lithology and the aggressive action of the sea (storms) have been responsible for the active erosion on the cliff face. In addition, this research applied geomatic techniques that have appeared commercially during the period (1956–2020), such as aerial photogrammetry, TLS, LiDAR, and UAV and analyzed the results to determine the precision that could be obtained with each method for its application to similar geomorphological structures. The combination of techniques and their adaptation to the geomorphological particularity and the orographic situation of the beach, serve as a reference for its application in the control of the dynamics of beaches and the retreat of cliffs.

In this chapter, a theoretical study relying on the thermal modelling of a Curie wheel, used for the conversion of low-grade waste heat into electrical power, is presented. It allows understanding the thermal behaviour of a Curie wheel operating in steady state in order to optimise its design. To this end, a stationary one-dimensional analytical thermal model, based on a Lagrangian approach, was developed. It allows determining the local distribution over time of the temperature in the magnetocaloric material exposed to a periodic sinusoidal heat source. Thanks to this model, the effects of different parameters (nature of the magnetocaloric material, nature and temperature of the fluid) were determined and analysed.

Yaw damper represents a major source of excitation for flexural vibration of the railway carbody. In order to reduce transmissibility of such undesired excitation, yaw damper should allow for large force transmission at low working frequencies, but should behave as vibration isolator at high working frequencies. Unfortunately, the yaw oil damper, which is nowadays in service, has poor intrinsic elastic capabilities and provides damping forces varying as a power function versus the piston speed. Since colloidal damper has intrinsic elastic capabilities and larger damping forces at lower excitation frequencies, it occurs as an attractive alternative solution to traditional yaw dampers. In this Chapter, firstly a simple but reliable analytical expression to estimate the negative damping occurring spontaneously during the hunting motion of the railway wheelset is presented, and the working conditions to be fulfilled by the yaw damper are clarified. Concretely, technical options to diminish the effects of the wheelset unstable hunting mode are listed, and the influence of the carriage geometry, hunting wavelength, and lateral perturbation on the stroke of the yaw damper is discussed. In order to estimate the effectiveness of the yaw damper, ride comfort evaluation of the bullet train subjected to lateral excitation is discussed relative to the standard procedure, and also by taking into account some particular frequency weightings which account for the discomfort sensation during the reading and writing activities performed by passengers. Then, the dynamic characteristics of a yaw colloidal damper, destined to carbody suspension of a full-scale bullet train, are evaluated from the experimental results obtained during horizontal vibration tests, performed on a ball-screw shaker. Both the frictional and colloidal effects are discussed versus the working stroke and frequency of the yaw colloidal damper. Compared to the corresponding classical yaw oil damper, the trial yaw colloidal damper allowed for: weight reduction of 31.6%; large damping force, dissipated energy and spring constant at long piston stroke under low excitation frequency; low damping force, dissipated energy and spring constant at short piston stroke under high excitation frequency. Observed elastic features of the yaw colloidal damper are justified based on a model which includes the effect of a porous lyophobic matrix on the behavior of a classical liquid spring.

The present work will highlight the experimental technique, elements expected in dental powder and conclusions therein. During the past decade medical research has demonstrated that this Hg is continuously released as vapor into mouth air; then it is inhaled, absorbed into body tissues, oxidized to ionic Hg, and finally covalently bound to cell proteins. Dental powder has been analyzed using conventional XRF and hand held XRF (HHXRF).The spectrum shows a large amount of Si, K, Ca and Zr in XRF and Al in HHXRF. The HHXRF has an advantage of showing Al which is a prominent element in dental powders. To obtain Al which is present in dental powders HHXRF is the preferred technique to conventional XRF. The present work will highlight the experimental technique, elements expected in dental powder and conclusions therein.

A sphere is an ideal shape in geometry. Whenever there is an enough mass clumps together to form an astronomical body, it tends to follow spherical shape. Irrespective of its material composition of any astronomical body, a diameter of few hundred kilometers is sufficient enough to create spherical form.  But there is always little deviation from the spherical form of astronomical bodies to be elliptical to be precise. So, almost all big enough astronomical bodies have elliptical form of shape. There is definitely symmetry between the elliptical shape of an astronomical body and elliptical orbit where other astronomical bodies revolving around. In this chapter, I will focus on the symmetry between shape and orbit of astronomical bodies. I will also focus on how a little deviation from the spherical shape allows the physical time to flow in forward direction. At the end, I will discuss why particles and anti-particles originate and recombine together.

The uncertainty principle states that the amount of uncertainty of a particle’s velocity multiplied by the amount of uncertainty of a particle’s position is a constant. In other words, the more certain about particle’s velocity, the less certain about particle’s position and vice versa. This chapter will focus on that the uncertainty measure is not a constant but a variable quantity. The uncertainty principle is situation based realism. In certain situations, it is more and in certain situations, it is less. The variable uncertainty principle is that the total amount of uncertainty of position and velocity multiplied by the total amount of certainty of position and velocity is a constant. I will also discuss that the physical time is a complex quantity and the variable uncertainty principle actually depends on the complex physical time. The complex physical time has two parts – the real physical time and the imaginary physical time.