Strong Physical Background Research Articles

Quantitative assessment of rock lithology from gamma-ray and mud logging data

The data on vertical variations of the rock lithological content along the geological profiles of boreholes are essential for interwell correlation, geological or hydrodynamic modeling, optimization of drilling process, etc. There are direct (investigation of core samples) and indirect (processing and interpretation of well-logging data) methods applied in petroleum engineering to determine rock lithology. Both approaches have several limitations (such as low quality of logging data in case of washouts, low frequency of sampling of drill cuttings, limited number of wells drilled with coring, etc.) calling for alternative approaches to determine rock lithological content along the borehole. One of the alternative solutions could be application of mud logging (drilling and mud gas data) due to the strong physical background of interrelations between drilling and mud gas data on one side and rock lithology on the other. Literature review shows that many of existing machine learning-based solutions assume application of mud logging data mainly for rock typing (qualitative assessment of rock lithology). Concurrently, many applied problems require quantitative data on rock lithology (volumetric concentrations of rock lithological components). To fill this gap, we assessed the capabilities of mud logging data for quantitative characterization of rock lithology. We proposed a new algorithm for the task at hand relying on special data processing and machine learning algorithms. As an input data we used drilling, mud gas, and gamma-ray data. The results of the developed algorithm application for three industrial wells confirmed the effectiveness of the developed algorithm. During our research we compared the performance of XGBoost algorithm and 1-D convolutional neural network. Obtained results allow concluding that the obtained regression models and developed algorithm exhibit good generalization ability providing the average total prediction uncertainty on unseen well of less than 0.15 c.u.

Comparison of convective heat transfer in metal foam-filled channels of three different cross-sections

This work introduces a new approach of analyzing convective heat transfer in porous medium by considering the foam structure as a type of fin. It provides the resulting heat transfer characteristics for the design of a longitudinally flowed tube bundle reformer used for the Micro Gas Turbine Solid Oxide Fuel Cell (MGT-SOFC) hybrid process. Owing to a limited experimental database available in literature for the above-mentioned situation, a physical model is initially introduced for a channel flow configuration between two large flat plates using a commercial PDE solver. This model is then validated with experimental results available in literature. A comparison with theoretical solutions is also conducted. Later, this model is modified/adapted for a pipe flow configuration. The physical model for a channel with representative cross-section shape of a longitudinally flowed tube bundle is more complex and is therefore built in a commercial CFD-Solver. A comparative study of the heat transfer behavior in channels of different cross-sections is performed based on a new dimensionless correlation, whose physical coherence with fin efficiency is explained and mathematically proved. The applicability of the heat transfer correlation from one cross-sectional shape to the other are discussed. The proposed new treatment of the porous medium as a fin structure considerably simplifies the heat transfer analysis in porous medium by the clear physical meaning behind fin efficiency and Biot number. This relationship contributes to a better understanding of the heat heat transfer characteristics in porous media in contrast to the correlation between Nusselt number and Reynolds number. Furthermore, this correlation enables a direct comparison between foam structures of different parameters because the fin efficiency is always between 0 and 1. The strong physical background of new correlations also enhances the reliability and plausibility at characterizing and designing the metal foam for heat transfer enhancement.

Once a physicist …

I appreciated Charles Day’s introduction to Physics Today’s most recent careers issue (October 2021, page 8). I am always delighted to see attention drawn to the wide range of satisfying careers that can be entered with a physics degree.The “Spotlight on Hidden Physicists” series in Sigma Pi Sigma’s Radiations magazine is very special to me as a matter of inclusion and personal perspective. I vividly recall reading letters in Physics Today around the time of the cancellation of the Superconducting Super Collider in 1993. Much was made of how the cancellation was (or wasn’t) the demise of US physics and how difficult it was for new PhD physicists to find proper jobs at the time. Industrial and other “hidden” physics jobs were not given much respect, and I don’t recall many letters that discussed the struggles of those with bachelor’s degrees in physics during that time.A few years later, I had the privilege of being elected to the National Council for the Society of Physics Students and Sigma Pi Sigma. Under the leadership of Gary White, the director from 2001 to 2012, I participated in developing the broad outline of the Hidden Physicists program. One of our goals was to combat the prevalent misconception that the only thing a physics degree was useful for was a career in academic or government research.That attitude is a great insult to the majority of physics degree holders, because only a relative few wind up in the business of publishing physics articles. Every year the country produces many more students with bachelor’s degrees in physics than with PhDs. For example, data from the 2019–20 academic year show that 9296 students received bachelor’s degrees in physics, while 1830 earned PhDs in the subject.11. S. Nicholson, P. J. Mulvey, Roster of Physics Departments with Enrollment and Degree Data, 2020: Results from the 2020 Survey of Enrollments and Degrees, AIP Statistical Research Center (September 2021). For the classes of 2019 and 2020, only about a third of physics bachelors pursued graduate degrees in physics or astronomy, and not all PhD graduates in those years ended up in “publish or perish” jobs.22. AIP Statistical Research Center, Initial Employment—Physics Bachelors and PhDs: Classes of 2019 and 2020 (March 2022).I espouse the view that completing any degree in physics alters a person’s worldview and influences them for the rest of their life, whether they wind up with a PhD in physics or a PhD in medieval literature (a path one of my students followed).Yes, it is a viewpoint akin to that of Aslan’s in The Lion, the Witch and the Wardrobe by C. S. Lewis: “Once a king or queen in Narnia, always a king or queen.” I concede that not everyone will be so inclusive. I strongly contend that someone who regularly uses their physics background is still a physicist, even if they are not publishing physics papers. That includes someone like the editor-in-chief of Physics Today, who must rely on a strong background in physics to be effective. So Charles, I recognize you as a physicist, and in your role at Physics Today, you were perhaps the most visible “hidden” physicist that I could imagine!ReferencesSection:ChooseTop of pageReferences <<1. S. Nicholson, P. J. Mulvey, Roster of Physics Departments with Enrollment and Degree Data, 2020: Results from the 2020 Survey of Enrollments and Degrees, AIP Statistical Research Center (September 2021). Google Scholar2. AIP Statistical Research Center, Initial Employment—Physics Bachelors and PhDs: Classes of 2019 and 2020 (March 2022). Google Scholar© 2022 American Institute of Physics.

Contributions of Loading and Unloading to Overpressure: Analytical Results from The Shelfal Area of The Lower Kutai Basin, Indonesia

DOI:10.17014/ijog.9.1.1-13A modified Bowers Method is applied to analyze the contribution of loading and unloading to total overpressure magnitude in the shelfal area of the Lower Kutai Basin. The method combines Bowers Method with density-sonic cross plots to differentiate contributors to overpressure. This method has a strong physical background, and has proven to give satisfactory overpressure estimation in the studied area. Several processes related to overpressure and compaction in the studied area have also been deduced: 1) top of overpressure is caused by unloading due to gas generation, 2) gas generation on its own can produce overburden-scale overpressure magnitude, 3) loading starts to contribute to overpressure at depth, where the lithology is dominated by mudrocks, 4) effective stress history experienced by mudrocks before unloading, and 5) the presence of two compaction lines and therefore two associated velocity-effective stress relations.

Teaching phonetics and speech science—What's changed and what hasn't

Many topics in articulatory phonetics that have been taught with traditional pedagogical techniques may be enhanced by the addition of acoustic information. However, it can be challenging to provide that information in ways that are accessible to students of Speech and Hearing, who often lack a strong background in physics. The ASA Committee on Education in Acoustics has offered sessions on acoustics demonstrations for ASA members. In meeting cities, the committee has hosted sessions for high school students and has co-sponsored sessions for Girl Scouts with Women in Acoustics. These sessions have resulted in a number of straightforward, accessible demonstrations of acoustics that are appropriate for use in undergraduate phonetics and speech science courses. This presentation will describe several traditional and computer-based demonstrations that may be used to teach speech acoustics to undergraduates in Speech and Hearing.

Pole-Zero Approach to Analyze and Model the Kink in Gain-Frequency Plot of GaN HEMTs

In this letter, we present a novel approach toward understanding the Kink effect (KE) in the bode plot of short circuit current gain ( ${h_{21}}$ ) observed for microwave transistors, particularly gallium nitride (GaN) HEMTs. We ascribe the origin of the KE to the presence of a pair of complex conjugate poles at the frequency of interest, introduced due to the extrinsic parasitic inductances and their interaction with the device intrinsic elements, such as the capacitances and transconductance, and develop simplified mathematical expressions that govern the behavior of the kink. We also present a physics-based compact model that is capable of capturing the KE and extensively validate the model against measured data for a GaN device under multibias conditions, thereby advocating the strong physical background of the model. We conclude by demonstrating the impact of various elements of the small signal model on the kink based on the developed mathematical hypothesis for KE.

Mihai V. Putz: Quantum nanochemistry

Chemists, physicists, and many others study matter. While the boundaries between these fields can be blurry, chemists and physicists are sometimes separated by the size of the matter that they examine. Chemists investigate matter at the atomic scale and above, while physicists look at the atomic scale and below. Professor Mihai Putz of the University of Timosoara, Romania, works at the atomic boundary in an attempt to better link physics and chemistry. As such, he has drawn on his peer-reviewed papers, lectures, conversations, and other sources to write a fivevolume set entitled Quantum Nanochemistry. In these volumes, Professor Putz aims to illuminate the physical underpinnings of matter. While the properties and interactions of matter have been well-described by many classical theories, quantum theory is needed to describe matter below the atomic scale. In these volumes, Professor Putz hopes to unite materials scientists, physicists, chemists, and others as quantum scientists, who use analytical descriptions of matter to inform their work. Over the five volumes, both quantum and classical approaches to understanding matter are explored. The first volume focuses on quantum physics, presenting an introduction to the basic theories and equations by describing the work of Bohr, Schrodinger, Einstein, and many others. The second volume opens with a history of chemistry and atomic theory. This volume then uses quantum theory to describe atoms, uniting the chemistry in the second book with the physics of the first. Quantum mechanical ideas of atomic periodicity, electronegativity, and more are developed. The third volume extends the ideas of the second in order to build quantized molecular models. This volume focuses heavily on the author’s theory of bondons—a quantum bosonic particle associated with chemical bonding. The fourth and fifth volumes expand the scope to solid materials and structure–property relationships, respectively. These books attempt to reach a broad audience and to cover a wide range of material. Concepts and ideas from engineering and materials science are mixed with those from chemistry and the history of science. While many of these concepts are given a lot of background information and explained well, a number of typographical and grammatical errors add confusion in some sections. Although these books reduce all concepts to mathematic and analytic descriptions whenever possible, so readers will be able to follow the main themes, especially for those with a strong background in physics and mathematics. The books heavily reflect the author’s presentations and past work, yet the later volumes draw extensively from the literature. The books include many references for interested parties to explore. The books also include a number of informative tables and figures that could serve as helpful references; however, despite the emphasis on teaching and describing analytic work, there are no example problems given. Overall, these five volumes cover a lot of material and work well to unite physicists and chemists as quantum scientists. The books are best used as a full set, as they weave common themes throughout. Due to the highly technical nature of the books, they would best be used by graduate students and other professional scientists in chemistry, physics, and any field that studies matter. & Benjamin D. Smith bdsmith@francis.edu

Kinetics of evolution of radiation induced micro-damage in ductile materials subjected to time-dependent stresses

The present paper aims at predicting evolution of radiation induced damage in the solids subjected to mechanical loads beyond the yield stress. Moreover, the evolution of radiation induced damage is combined with the evolution of mechanically induced damage within the common framework of Continuum Damage Mechanics (CDM). An additive formulation with respect to damage parameters (tensors) has been postulated. Multiscale constitutive model containing strong physical background related to the mechanism of generation of clusters of voids in the irradiated solids has been built. The model is based on the experimental estimation of concentration of lattice defects (interstitials, di-interstitials, interstitial clusters, vacancies, di-vacancies, vacancy clusters) in Al as a function of dpa (displacement per atom), and comprises the relevant kinetics of evolution of radiation induced damage under mechanical loads. Two kinetic laws of damage evolution were taken into account: the Rice & Tracey model and – for comparison – the Gurson model. As an application, estimation of lifetime of a cylindrical shell (coaxial target embedded in a detector of particles) subjected to combination of irradiation and mechanical loads, has been carried out. It is demonstrated that the number of cycles to failure depends strongly on the accumulation of micro-damage due to irradiation. The lifetime of irradiated components has been expressed as a function of two parameters: maximum dpa and axial stress amplitude on cycle.

A generalized G-SFED continuum solvation free energy calculation model

An empirical continuum solvation model, solvation free energy density (SFED), has been developed to calculate solvation free energies of a molecule in the most frequently used solvents. A generalized version of the SFED model, generalized-SFED (G-SFED), is proposed here to calculate molecular solvation free energies in virtually any solvent. G-SFED provides an accurate and fast generalized framework without a complicated description of a solution. In the model, the solvation free energy of a solute is represented as a linear combination of empirical functions of the solute properties representing the effects of solute on various solute-solvent interactions, and the complementary solvent effects on these interactions were reflected in the linear expansion coefficients with a few solvent properties. G-SFED works well for a wide range of sizes and polarities of solute molecules in various solvents as shown by a set of 5,753 solvation free energies of diverse combinations of 103 solvents and 890 solutes. Octanol-water partition coefficients of small organic compounds and peptides were calculated with G-SFED with accuracy within 0.4 log unit for each group. The G-SFED computation time depends linearly on the number of nonhydrogen atoms (n) in a molecule, O(n).

Echo-Doppler assessment of diastole: flow, function and haemodynamics

The concepts related to diastolic function were developed by muscle physiologists and by cardiologists with a strong background in physics (cardiac mechanics and fluid dynamics). These scientists described left ventricular...

Viscosity modeling of some oxygenated fuels

The dynamic viscosity modeling of nine oxygenated fuels (diethyl ether, diisopropyl ether, dibutyl ether, dimethoxymethane, 1,2-dimethoxyethane, diethylene glycol dimethyl ether, dimethyl carbonate, diethyl carbonate and diethyl adipate) was presented with several representative models. The evaluated viscosity models range from empirical model, semi-empirical model such as residual viscosity, to models with strong physical background such as hard-sphere scheme and free-volume viscosity model. The evaluation results indicated that the Assael five parameters model has the best performance for the studied fluid. Similar to the hard-sphere, free-volume model has a physical and theoretical background and related to characteristic parameters, making this model totally predictive for the dense fluid.

Prediction of the n‐hexane/water and 1‐octanol/water partition coefficients for environmentally relevant compounds using molecular simulation

AbstractIn recent years molecular simulation has emerged as a useful tool to predict physical properties of complex chemical systems. A methodology to estimate the n‐hexane/water and 1‐octanol/water partition coefficients of environmentally relevant solutes, namely substituted alkyl‐aromatic molecules, chlorobenzenes, polychlorinated biphenyls (PCBs) and polychlorinated diphenyl ethers (PCDEs) using molecular simulation is elucidated here. The partition coefficients are calculated based on the absolute solvation Gibbs energies in each phase which are estimated from molecular dynamics simulations employing the thermodynamic integration approach. Very encouraging results, with average absolute deviations of 0.4 log P units are presented. Consequently, this molecular‐based approach with a strong physical background can provide reliable prediction of the partition coefficients in different solvent pairs without the a priori knowledge of experimental data. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1929–1938, 2012

High-Pressure Acid-Gas Viscosity Correlation

Acid gases containing hydrogen sulfide (H2S) are often encountered in the petroleum industry. However, reliable experiments on their thermophysical properties in reservoir conditions, on viscosity in particular, are scarce. From a modeling point of view, H2S and carbon dioxide (CO2) are polar compounds and as such are often considered rather difficult to model accurately. In this work, we propose a correlation with a strong physical background based on a corresponding-states (CS) approach to predict the viscosity from the temperature and the density of a large variety of systems for all stable thermodynamic states (gas, liquid, and supercritical). In particular, this correlation is applicable to predict the viscosity of sour/acid-gas mixtures, whatever the thermodynamic conditions. This approach is based on the Lennard-Jones (LJ) fluid model, which has been studied extensively thanks to molecular-dynamics (MD) simulations over a wide range of thermodynamic conditions. This fluid model can be extended to deal with polar molecules such as CO2 or H2S without a loss of accuracy. First, we demonstrate that the proposed physically based correlation is able to provide an excellent estimation of the viscosity [with average absolute deviations (AADs) below 5%] of pure compounds, including normal-alkanes, CO2, or even H2S, whatever the thermodynamic conditions (gas, liquid, or supercritical). Then, using a one-fluid approximation and a set of combining rules, the correlation is applied to various fluid mixtures in a fully predictive way (i.e., without any additional fitted parameters). Using this scheme, the deviations between predictions and measurements are as low as those on pure fluids using temperature and density as inputs. The viscosity of natural- and acid-gas mixtures at reservoir conditions is shown to be very well predicted by the proposed scheme. In addition, it is shown that this correlation can also be applied to predict reasonably the viscosity of asymmetric high-pressure mixtures, even in the liquid phase. This physically based approach is easy to include in any simulation software as long as, apart from temperature and density, the only inputs--the molecular parameters of each species--can be estimated from the critical temperature and the critical volume when not known.

Endogenous Retroviruses: Thierry Heidmann wins the 2009 Retrovirologyprize

Thierry Heidmann wins the 2009 Retrovirology prize.

Development of wall models for LES of separated flows using statistical evaluations

Wall models are the key technology making possible the application of large eddy simulation to flows of engineering interest. In this paper, a new approach to the development of wall models is presented, which, in contrast to classical wall models, relies on a strong physical background and therefore is considered to be able to predict separated flows reliably. The idea is based on the concept of artificial viscosity. It requires definitions of the distribution of the eddy viscosity in the outer layer and the thickness of the viscous sublayer. The second issue is the critical aspect. Applying the artificial viscosity approach to the needs of LES wall modeling is discussed in detail and promising wall models are derived analytically. Statistical evaluations using nonlinear stochastic estimation are carried out in order to determine an important physical dependence involved in the new wall models, namely the ratio of the thickness of the viscous sublayer to the height of the wall-nearest cell. As test cases, the flow in plane channels and over a periodic arrangement of hills is considered. A posteriori results show clearly the advantages of the wall models developed, especially for separated flows.

XANES Spectroscopy: A Promising Tool for Toxicology:: A Tutorial

X-ray absorption near edge structure (XANES) spectroscopy can provide information on the oxidation state of metal ions within a biological sample and also the complexes in which it is found. This type of information could be of great use to toxicologists in understanding the mechanism of action of many toxic agents. The prospect of using a sophisticated physical technique such as XANES may be somewhat intimidating for those without a strong physical background. Here, we explain the concepts necessary to understand XANES spectroscopy at a level that can be easily understood by biological scientists without a strong physics background and describe useful sample preparation and data analysis techniques which can be adapted for a variety of applications. Examples are taken from an ongoing study of manganese in brain mitochondria and neuron-like cells.

High pressure viscosity and density modeling of two polyethers and two dialkyl carbonates

This paper reports results concerning the dynamic viscosity η and the density ρ of four pure substances (dimethyl carbonate, diethyl carbonate, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether) as a function of pressure (up to 100 MPa) and temperature (from 283.15 to 353.15 K). All our previously published, Int. J. Thermophy. 22 (2001) 749, experimental values (184 values for viscosity and 410 values for density) have been used in order to test several representative models. The density is discussed with six equations of state (Peng–Robinson, Soave–Redlich–Kwong, Soave–Redlich–Kwong modified, Lee–Kesler, Patel–Teja, and Nishiumi–Saı̈to) and with the Tait representation. The viscosity is discussed with empirical models, with semi-empirical models such as a self-referencing model and a model based on residual viscosity, and with models with strong physical background such a model based on the hard-sphere scheme, and a free-volume viscosity model.