Physical Basis Research Articles

An Overview of Geophysical Techniques and Their Potential Suitability for Archaeological Studies

The need to study, protect, and conserve archaeological heritage has enhanced the application of geophysical techniques as non-invasive and reliable tools to investigate fragile and valuable assets. This review presents the most popular geophysical techniques suitable for archaeogeophysical investigations, namely, magnetometry, ground penetrating radar, and electrical resistivity tomography, together with a series of multiparametric measures taken from aerial platforms (UAS). For each method, we recall the basic physical principles, illustrate the operative procedures for field investigation, and provide indications about data processing and modeling. We propose a flowchart to address reliable and effective geophysical investigations, from its planning to the development of the final archaeogeophysical model. We underline the integrated approach, in which the combination of various techniques allows the best results in terms of resolution, coverage, investigation depth, speed, and costs to be obtained. We introduce a suite of studied cases in which this approach has been applied successfully.

A semi-analytical radiative transfer model for explaining soil spectral features

Spectral techniques play a key role in the estimation of large-scale soil parameters, but most of the current estimation models are data-driven models lacking a physical basis. Therefore, in this study, we developed a novel radiative transfer model named the soil multifactor radiative transfer (SMRT) model that predicts the soil spectra as a function of the soil organic matter (SOM), particle size distribution (PSD), and iron oxide content. The SMRT model explains the soil spectral features commonly used in the data-driven estimation models and can be used to explore the mechanisms by which soil-related parameters affect soil spectra according to the model parameters. A total of 79 soil profile datasets were used in the experiments conducted in this study. The reflectance of the soil after air-drying can ignore the effect of moisture, thereby ensuring that the main influences on the soil spectra are the SOM, iron oxide content, and PSD. The SMRT model performed very well in the spectral simulation (R2 = 0.9681, RMSE = 0.0266, MAE = 0.0160). The absorption and scattering coefficients of the SMRT model explain the radiative transfer mechanism for the color representation of black soil and laterite soil. The spectral features around 1910 nm and 2210 nm are caused by not only the soil moisture (SM) and clay mineral content, but several other factors, including the SOM, iron oxide content, and PSD. Overall, these findings show that the SMRT model has a superior ability to describe the soil radiative transfer processes. However, as the coefficients in the SMRT model are dependent on the soil properties, the coefficients should be calibrated by an optimization algorithm and cannot be constants, which leads to the requirement for soil samples to calibrate the coefficients in practical applications.

A Physical Basis for Kinetic Compensation.

Kinetic compensation is a strong, positive correlation between the Arrhenius activation energy E and the frequency factor A for a reaction between the same reactants under similar experimental conditions or similar reactants under the same conditions, even though these parameters are supposed to be independent. The kinetic compensation effect (KCE) is demonstrated by a linear relationship between ln[A] and E/R in the eponymous Constable plot and has been the subject of more than 50 000 publications over the past 100 years, with no consensus opinion about the cause of this effect. In this paper, it is suggested that the linear relationship between ln[A] and E is the result of a real or spurious path dependence of the reaction history between the initial state of the pure reactant(s) and the final state of the pure product(s) having standard enthalpy and entropy differences, ΔH° and ΔS°, respectively. The single-step rate law approximation of a reversible reaction leads to T0 = H°/ΔS° as the dynamic thermal (thermodynamic) equilibrium temperature and 1/T0 = (ln[A̅/k0])/(E̅/R) as the slope of a Constable/KCE plot or the crossover temperature of Arrhenius lines in an isokinetic relationship (IKR), where A̅ and E̅ are mean values for the ensemble of compensating {Ei, Ai} pairs and k0 is a constant that accounts for the path dependence of the reaction history and reconciles the KCE with the IKR. This proposed physical basis for the KCE and IKR is supported by qualitative agreement between ΔH° and ΔS° calculated from the statistics of compensating {Ei, Ai} pairs in the literature, and the difference in the standard enthalpies and entropies of formation of the products and reactants for thermal decomposition of organic peroxides, calcium carbonate, and poly(methyl methacrylate).

Effects of multimedia on psychometric characteristics of cognitive tests: A comparison between technology-based and paper-based modalities

The study aims to investigate the effects of delivery modalities on psychometric characteristics and student performance on cognitive tests. A first study assessed the inductive reasoning ability of 715 students under the supervision of teachers. A second study examined 731 students’ performance on the application of the control-of-variables strategy in basic physics but without teacher supervision due to the COVID-19 pandemic. Rasch measurement showed that the online format fitted to the data better in the unidimensional model across two conditions. Under teacher supervision, paper-based testing was better than online testing in terms of reliability and total scores, but contradictory findings were found in turn without teacher supervision. Although measurement invariance was confirmed between two versions at item level, the differential bundle functioning analysis supported the online groups on the item bundles constructed of figure-related materials. Response time was also discussed as an advantage of technology-based assessment for test development.

Reversal of spin-polarization near the Fermi level of the Rashba semiconductor BiTeCl

Spin–orbit coupling forms the physical basis for quantum materials with non-trivial topology and potential spintronics applications. The Rashba interaction is a textbook model of spin–orbit interactions, with charge carriers undergoing linear, isotropic spin-splitting in momentum space. Recently, non-centrosymmetric semiconductors in the family BiTeX (X = Cl, Br, I) have been identified as exemplary Rashba materials due to the strong splitting of their bulk bands, yet a detailed investigation of their spin textures, and their relationships to local crystal symmetry, is currently lacking. We perform high-efficiency spin-resolved photoemission spectroscopy to directly image the spin texture of surface states of BiTeCl, and we find dramatic deviations from idealized behavior, including a reversal of the spin-polarization near the Fermi level. We show that this behavior can be described by higher-order contributions to the canonical Rashba model with the surface states localized to individual trilayers of the crystal. Due to the prominence of these effects near the Fermi level, they should have a strong impact on the spin-dependent transport of carriers.

The Effect of Using the Project Based Learning (PjBL) Learning Model to Increase UPI YPTK Padang Students' Understanding of the Application of Basic Physics Courses

The linkage and coherence of Basic Physics material with material applications in real life is a new problem in Basic Physics lectures at Putra Indonesia University YPTK Padang. The purpose of this study was to see the effect of using the PjBL model to increase students' understanding of the application of the Basic Physics course. This type of research was a quasi-experimental involving a research sample of Informatics Engineering students at the Faculty of Computer Science UPI YPTK Padang who took the Basic Physics course in the 2019/2020 academic year. The sampling technique used is random sampling. In this study the sample class was divided into two categories, namely the experimental class of 51 students and the control class of 51 students. The instrument used is a work assessment sheet in the form of a portfolio. The data analysis technique used was an independent sample t-test, with prerequisite tests first being carried out, namely normality and homogeneity tests. Based on the results of the data analysis performed, the sig-2 tailed value for the independent sample t-test was 0.00 < of the value α = 0.05 . The conclusion from this study is that there are differences in student understanding between classes whose lectures use the PjBL model and classes that carry out conventional learning.

Challenges in Hydrologic‐Land Surface Modeling of Permafrost Signatures—A Canadian Perspective

AbstractPermafrost thaw/degradation in the Northern Hemisphere due to global warming is projected to accelerate in coming decades. Assessment of this trend requires improved understanding of the evolution and dynamics of permafrost areas. Land surface models (LSMs) are well‐suited for this due to their physical basis and large‐scale applicability. However, LSM application is challenging because (a) LSMs demand extensive and accurate meteorological forcing data, which are not readily available for historic conditions and only available with significant biases for future climate, (b) LSMs possess a large number of model parameters, and (c) observations of thermal/hydraulic regimes to constrain those parameters are severely limited. This study addresses these challenges by applying the MESH‐CLASS modeling framework (Modélisation Environmenntale communautaire—Surface et Hydrology embedding the Canadian Land Surface Scheme) to three regions within the Mackenzie River Basin, Canada, under various meteorological forcing data sets, using the variogram analysis of response surfaces framework for sensitivity analysis and threshold‐based identifiability analysis. The study shows that the modeler may face complex trade‐offs when choosing a forcing data set; for current and future scenarios, forcing data require multi‐variate bias correction, and some data sets enable the representation of some aspects of permafrost dynamics, but are inadequate for others. The results identify the most influential model parameters and show that permafrost simulation is most sensitive to parameters controlling surface insulation and runoff generation. But the identifiability analysis reveals that many of the most influential parameters are unidentifiable. These conclusions can inform future efforts for data collection and model parameterization.

Frequency-Domain Analysis and Design of Thomson-Coil Actuators

Thomson coil actuators consist of an electric coil repelling a metallic disk. They are considered the fastest electromagnetic actuators for short displacements and for this reason are favored for DC circuit breakers. Although the basic physics are understood, the actuator's minimal components are very interdependent, making analysis difficult. Actuator design so far has thus been limited to trial and error based on finite-element models. In this paper, a novel approach is presented based on the electromagnetic frequency response of the actuator. This method is shown to be an intriguing analysis tool and various actuator design directions are presented. Experimental results provide a confirmation of the analysis.

Recent progress and perspective on batteries made from nuclear waste

Sustainable energy sources are an immediate need to cope with the imminent issue of climate change the world is facing today. In particular, the long-lasting miniatured power sources that can supply energy continually to power handheld gadgets, sensors, electronic devices, unmanned airborne vehicles in space and extreme mining are some of the examples where this is an acute need. It is known from basic physics that radioactive materials decay over few years and some nuclear materials have their half-life until thousands of years. The past five decades of research have been spent harnessing the decay energy of the radioactive materials to develop batteries that can last until the radioactive reaction continues. Thus, an emergent opportunity of industrial symbiosis to make use of nuclear waste by using radioactive waste as raw material to develop batteries with long shelf life presents a great opportunity for sustainable energy resource development. However, the current canon of research on this topic is scarce. This perspective draws fresh discussions on the topic while highlighting future directions in this wealthy arena of research.Graphical abstractA long-lasting miniaturised nuclear battery utilising 14C radioactive isotope as fuel

Quartz tuning fork based photoacoustic spectroscopy and sensing

Quartz crystal tuning forks (QTFs) resonators are key components for timing and frequency measurements, due to their high stability, high-quality factors and low power consumptions. Thanks to their piezoelectric properties, QTFs are employed as sensitive element in many fields and systems such as atomic force microscopy, near-field and microwave microscopy, and mass/viscosity sensor. Since 2002, QTFs are also widely used as a sharply resonant acoustic transducer to detect weak photoacoustic excitation for Quartz-Enhanced Photoacoustic Spectroscopy (QEPAS). Among most sensitive optical techniques, QEPAS was demonstrated as the leading-edge technology for addressing these application requirements, providing also modularity, ruggedness, portability and allowing the use of extremely small volumes. QEPAS technique does not require an optical detector, it is wavelength independent, it is immune to environmental noise and can operate in a wide range of temperature and pressure. These factors, together with its proven reliability and ruggedness, represent the main distinct advantages with respect to other laser-based techniques for environmental monitoring and in situ detection. Starting from the basic physical principles governing the QTF physics, I will review the main results achieved by exploiting custom QTFs for QEPAS sensing and as photodetector in LITES setup, with a main focus on real-world applications.

Information parity increases on functional brain networks under influence of a psychedelic substance

The physical basis of consciousness is one of the most intriguing open questions that contemporary science aims to solve. By approaching the brain as an interactive information system, complex network theory has greatly contributed to understand brain process in different states of mind. We study a non-ordinary state of mind by comparing resting-state functional brain networks of individuals in two different conditions: before and after the ingestion of the psychedelic brew Ayahuasca. In order to quantify the functional, statistical symmetries between brain region connectivity, we calculate the pairwise information parity of the functional brain networks. Unlike the usual approach to quantitative network analysis that considers only local or global scales, information parity instead quantifies pairwise statistical similarities over the entire network structure. We find an increase in the average information parity on brain networks of individuals under psychedelic influences. Notably, the information parity between regions from the limbic system and frontal cortex is consistently higher for all the individuals while under the psychedelic influence. These findings suggest that the resemblance of statistical influences between pair of brain regions activities tends to increase under Ayahuasca effects. This could be interpreted as a mechanism to maintain the network functional resilience.

Finding wave equations for sediment acoustic theories

The two main theories for wave propagation in sediments, the Extended Biot theory and the Viscous Grain Shearing (VGS) theory, have been formulated in terms of dispersion equations only. Some have considered the lack of a wave equation to be a weakness that may indicate lack of a physical basis for these theories. In the Biot theory, it is the frequency-dependent viscodynamic operator which models viscous boundary effects in pores that poses the problem. It can be formulated as a ratio of Bessel functions for circular pores and as a ratio of tanh-functions for a 2D parallel plane duct. There is no simple equivalent time domain operator for use in the wave equation. In both geometries, the factor may, however, be approximated well with (1 + icω)1/2, where c is a constant. This factor also appears in the Cole-Davidson dielectric theory for complex media. The equivalent time domain operator, the fractional pseudo-differential operator, enables the formulation of wave equations for all three wave modes. The same operator turns out to be central for transforming the dispersion relations of the VGS theory to time-space wave equations. These wave equations enable a closer study of properties of the medium models than that obtained from dispersion relations alone.

A Thermodynamically-based Modeling for the Creep and Plasticity of Al 5083 Alloy

To ensure a thermodynamic consistency for a constitutive model is a higher request for modeling the mechanical behaviors of materials. This paper conducts a thermodynamic analysis for a creep-plasticity model for Al 5083 alloy. The constitutive equations are derived from the fundamental thermodynamic laws, maintaining a rigorous physical basis of the proposed model. The monotonic tensile and creep tests are introduced for modeling, illustrating the rationality and accuracy of the proposed model.

Understanding element solution energies in nickelbase alloys using machine learning

The design of nickelbase superalloys requires to tune the content of different phases with a composition of Ni3A, either to strengthen the alloy (-phase, Ni3Al, γ″-phase, Ni3Nb) or to influence its grain size and avoid embrittlement (δ-phase, Ni3Nb, η-phase, Ni3Ti). Here, we use a machine-learning-inspired approach to understand the influence of elemental properties on the energy of an alloying element in the respective phases. It is shown that the energy in γ″, δ, and η can be fitted well using the Bader charge and the volume of the element in a nickel matrix. In the case of , the small lattice mismatch requires a fit not involving the volume, but the bond order instead. We also show that the frequently used M d -parameter can be predicted from the properties of an element in a pure nickel matrix. Finally, the physical basis of the results is discussed in detail.

Plane Geometry Inspires Wave Engineering Starters [Educator’s Corner

Plane geometry, in academia, often helps students intuitively understand something difficult to do with algebra. Graphics provide rich visual information rather than equations. This idea applies to postulates and theorems in a variety of scientific and technical fields. Although they are specially useful in understanding wave engineering, students sometimes find it difficult to first learn wave-specific concepts, such as S-parameters and voltage standing wave ratios (VSWRs). If we introduce those concepts by performing a persuasive graphical demonstration on a blackboard, students become familiar with them more smoothly than if we use only algebra. What concepts in our field, then, can we effectively translate into graphics? As an attempt to address the question, this article presents eight instructive figures signifying basic physics in wave engineering.

Implementation of Project Based Learning (Pjbl) at Basic Physics Course Based on Aeromodelling Project

The objective of this study was to describe students' abilities through Project Based Learning in Basic Physics courses with aeromodelling aircraft manufacturing projects. This research was conducted using a One-Shot Case Study design with subjects consisting of a classroom with a total of 57 students in the teaching and education faculties. Research data obtained from pretest - posttest analysis. Data analysis with percentage technique was then processed descriptively. The results showed that students' comprehension abilities increased with a significant increase in grades. From this study it can be concluded that the Project Based Learning learning model can improve students' understanding abilities

Attachment-line, crossflow and Tollmien-Schlichting instabilities on swept ONERA-D and Joukowski airfoils.

Linear stability analyses are performed to investigate the boundary layer instabilities developing in an incompressible flow around the whole leading-edge of swept ONERA-D and Joukowski airfoils of infinite span. The stability analyses conducted in our study are global in the chordwise direction and local in the spanwise direction. A neutral curve is drawn at a given leading-edge Reynolds number ReR and several overlapping regions, called "lobes", are identified on a physical basis. A detailed study of the marginal modes reveals the presence of attachment-line and crossflow instabilities, as well as modes whose features do not fall within the standards of a specific type. Connected crossflow/Tollmien-Schlichting modes, that show a dominant spatial structure reminiscent of Tollmien-Schlichting waves but whose destabilization is linked to a crossflow mechanism, have been identified. The comparison of several neutral curves at different ReR values reveals the greater stabilizing effect of the increase of ReR on the crossflow instability compared to the attachment-line instability. The influence of the airfoil shape is also studied by comparing the neutral curves of the ONERA-D with the neutral curves of the Joukowski airfoil. These curves reveal similar characteristics with the presence of distinct lobes and their comparison at constant sweep angle shows that, under the conditions studied, the ONERA-D airfoil is more stable than the Joukowski airfoil, even for crossflow instabilities. The absolutely or convectively unstable nature of the flow in the spanwise direction is also tackled and our results suggest that the flow is only convectively unstable.

Development and Application of a Mechanistic Nutrient-Based Model for Precision Fish Farming

This manuscript describes and evaluates the FEEDNETICS model, a detailed mechanistic nutrient-based model that has been developed to be used as a data interpretation and decision-support tool by fish farmers, aquafeed producers, aquaculture consultants and researchers. The modelling framework comprises two main components: (i) fish model, that simulates at the individual level the fish growth, composition, and nutrient utilization, following basic physical principles and prior information on the organization and control of biochemical/metabolic processes; and (ii) farm model, that upscales all information to the population level. The model was calibrated and validated for five commercially relevant farmed fish species, i.e., gilthead seabream (Sparus aurata), European seabass (Dicentrarchus labrax), Atlantic salmon (Salmo salar), rainbow trout (Oncorhynchus mykiss), and Nile tilapia (Oreochromis niloticus), using data sets covering a wide range of rearing and feeding conditions. The results of the validation of the model for fish growth are consistent between species, presenting a mean absolute percentage error (MAPE) between 11.7 and 13.8%. Several uses cases are presented, illustrating how this tool can be used to complement experimental trial design and interpretation, and to evaluate nutritional and environmental effects at the farm level. FEEDNETICS provides a means of transforming data into useful information, thus contributing to more efficient fish farming.

ANALISIS KEMAMPUAN INTERPRETASI GRAFIK MAHASISWA PADA MATERI GERAK LURUS

Graphs are a form of presenting data that shows relationships or comparisons between variables as well as patterns and tendencies of a data. The ability to interpret graphs is needed so that we can get the right information from the data presented. In basic physics courses, a lot of data is presented in graphical form, one of which is in the material of straight motion. This research is a quantitative descriptive study that aims to determine students' abilities in interpreting graphs on straight motion material in basic physics courses. The instrument used was in the form of multiple choice questions which were tested on 26 students participating in basic physics courses. Based on the data analysis carried out, the result was that students' interpretation abilities in general were still low where on average students were only able to solve graph interpretation questions by 21.8% and only 7.7% of students were able to complete graph interpretation questions up to 50%.

The Different Bases of the Meaning and of the Seeing-in Experiences

There are some complex experiences, such as the experiences that allow us to understand linguistic expressions and pictures respectively, which seem to be very similar. For they are stratified experiences in which, on top of grasping certain low-level properties, one also grasps some high-level semantic-like properties. Yet first of all, those similarities notwithstanding, a phenomenologically-based reflection shows that such experiences are different. For a meaning experience has a high-level fold, in which one grasps the relevant expression’s meaning, which is not perceptual, but is only based on a low-level perceptual fold that merely grasps that expression in its acoustically relevant properties. While a pictorial experience, a seeing-in experience, has two folds, the configurational and the recognitional fold, in which one respectively grasps the physical basis of a picture, its vehicle, and what the picture presents, its subject, that are both perceptual, insofar as they are intimately connected. For unlike a meaning experience, in a seeing-in experience one can perceptually read off the picture’s subject from the picture’s vehicle. Moreover, this phenomenological difference is neurologically implemented. For not only the cerebral areas that respectively implement such experiences are different, at least as far as the access to those experiences’ respective high-level content is concerned. As is shown by the fact that one can selectively be impaired in the area respectively implementing the meaning vs. the seeing-in experience without losing one’s pictorial vs. semantic competence respectively. But also, unlike meaning experiences, the area implementing the seeing-in experiential folds is perceptual as a whole. For not only a picture’s subject can be accessed earlier than an expression’s meaning, but also the neural underpinnings of such folds are located in the perceptual areas of the brain.