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Strain Characteristics Of Soils And The Methods Of Their Determinatio, K. S. Sultanov, P. V. Loginov, Z. R. Salikhova, S. M. Takhirov

Irrigation and Melioration

A method is proposed for determining the strain characteristics of soils under dynamic loads, based on the results of experiments on dynamic compression of soils in laboratory conditions on a device of dynamic loading and for solving a wave problem, the statement of which is identical to the statement of the experiment. With the proposed method, the dynamic and static compression moduli, the unloading modulus, the viscosity coefficient of loess soil in the range of seismic loads were determined in accordance with the elastic-viscoelastic soil model developed by G.M. Lyakhov.

Strain Characteristics Of Soils And The Methods Of Their Determinatio, K. S. Sultanov, P. V. Loginov, Z. R. Salikhova, S. M. Takhirov

Irrigation and Melioration

A method is proposed for determining the strain characteristics of soils under dynamic loads, based on the results of experiments on dynamic compression of soils in laboratory conditions on a device of dynamic loading and for solving a wave problem, the statement of which is identical to the statement of the experiment. With the proposed method, the dynamic and static compression moduli, the unloading modulus, the viscosity coefficient of loess soil in the range of seismic loads were determined in accordance with the elastic-viscoelastic soil model developed by G.M. Lyakhov.

Underdamped Motion Of A Microbead In Optical Tweezer And Its Relationship With The Reynolds Number, Vatsal Asitkumar Joshi

Mechanical and Aerospace Engineering Theses

Optical tweezers can hold and manipulate microscopic objects with the use of a highly focused laser beam. The radiation pressure acting on the object is generally in the range of piconewtons and can be attractive or repulsive based on the reflective indexes of the object and the surrounding medium. Though the advances in the field of Optical tweezers have been enormous in the past few years, only the object's planer motion can be analyzed with the motion capture technology available today. Due to the wide applications of Optical tweezers in the field of biology and physics, the ability to simulate …

Dynamic Modeling And Analysis Of Propulsion Effect Of 3 Dof Robot, Ahmet Shala, Xhevahir Bajrami

International Journal of Business and Technology

Dynamical Modeling of robots is commonly first important step of Modeling, Analysis and Control of robotic systems. This paper is focused on using Denavit-Hartenberg (DH) convention for kinematics and Newton- Euler Formulations for dynamic modeling of 3 DoF - Degree of Freedom of 3D robot. The process of deriving of dynamical model is done using Software Maple. Simulations are done using Matlab/Simulink for analysis of propulsion effect under Earth gravity when First Link rotates with 1000 rpm, second Link can move free in vertical direction and Third Link can rotates free around their rotations axle. Simulations results shows very good …

Sampling Frequency Influences Sample Entropy Of Kinematics During Walking, Peter C. Raffalt, John D. Mccamley, William Denton, Jennifer M. Yentes

Journal Articles

Sample entropy (SaEn) has been used to assess the regularity of lower limb joint angles during walking. However, changing sampling frequency and the number of included strides can potentially affect the sample entropy. The present study investigated the effect of sample frequency and the number of included strides on the calculations of SaEn in joint angle signals recorded during treadmill walking. Eleven subjects walked at their preferred walking speed for 10 minutes, and SaEn was calculated on sagittal plane hip, knee and ankle angle signals extracted from 50, 100, 200, 300 and 400 strides at sampling frequencies of 60, 120, …

Current-Driven Production Of Vortex-Antivortex Pairs In Planar Josephson Junction Arrays And Phase Cracks In Long-Range Order, Francisco Estellés-Duart, Miguel Ortuño, Andrés M. Somoza, Valerii M. Vinokur, Alex Gurevich

Physics Faculty Publications

Proliferation of topological defects like vortices and dislocations plays a key role in the physics of systems with long-range order, particularly, superconductivity and superfluidity in thin films, plasticity of solids, and melting of atomic monolayers. Topological defects are characterized by their topological charge reflecting fundamental symmetries and conservation laws of the system. Conservation of topological charge manifests itself in extreme stability of static topological defects because destruction of a single defect requires overcoming a huge energy barrier proportional to the system size. However, the stability of driven topological defects remains largely unexplored. Here we address this issue and investigate numerically …

Catalysis Of Stark-Tuned Interactions Between Ultracold Rydberg Atoms, A. L. Win, W. D. Williams, T. J. Carroll, C. I. Sukenik

Physics Faculty Publications

We have experimentally investigated a catalysis effect in the resonant energy transfer between ultracold ⁸⁵Rb Rydberg atoms. We studied the time dependence of the process, 34p + 34p → 34s + 35s, and observed an enhancement of 34s state population when 34d state atoms are added. We have also performed numerical model simulations, which are in qualitative agreement with experiment and indicate that the enhancement arises from a redistribution of p-state atoms due to the presence of the d-state atoms.

Developing A Femtosecond Stimulated Raman Spectroscopy Experiment For Solid State Materials, Daniel Hammerland

Electronic Theses and Dissertations

Femtosecond Stimulated Raman Spectroscopy (FSRS) is a ultrafast spectroscopy technique first implemented by chemists to understand isomerization and other ultrafast molecular morphology changes by resolving vibrational dynamics[1, 2, 3]. FSRS has an unparalleled temporal and spectral resolution [4, 1, 5, 6] that arises as a result of a clever combination of picosecond and femtosecond pulses. However, despite this capability, FSRS has yet to be applied to modern materials in condensed matter physics. This thesis explores the design and implementation of FSRS to study two-dimensional materials in order to measure their quantum confined vibrational dynamics on utlrafast time scales.

A Dual-Process Team Mood Framework Of Team Creativity, Sean Teck Hao Lee

Dissertations and Theses Collection (Open Access)

While it has been recognized that mood can exert a substantive influence on an individual’s level of creativity, much of the creative needs of organizations today are being fulfilled by brainstorming teams rather than individual employees. As such, researchers have begun to examine the effects of mood on creativity in the context of teams. Existing findings, unfortunately, have not been consistent, such that positive mood has been shown to be beneficial towards team creativity at times (e.g., Grawitch, Munz, Elliott, & Mathis, 2003), while at other times being harmful towards team creativity (e.g., Tsai, Chi, Grandey, & Fung, 2012). Similarly, …

Investigations Into Factors Affecting The Wpd-Loop In The Protein Tyrosine Phosphatases Yoph And Ptp1b, Gwendolyn Moise

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The research in this dissertation documents connections between the primary amino acid sequence of proteins, the dynamics of proteins, and their catalytic function. This research project studied two proteins called protein-tyrosine phosphatases (PTPs): the human enzyme PTP1B, and the bacterial enzyme YopH. PTP1B is a human enzyme that down regulates the insulin receptor on the outer cellular membrane, and causes the insulin receptor to be less responsive to insulin. A deeper knowledge of how PTP1B is different from other human PTPs might be useful in designing drugs to increase insulin sensitivity in diabetics. Yersinia Pestis is the bacteria that caused …

A Comparison Of The Effects Of Enhanced Hands-On Intervention Versus Textbook Interventions To Understand Student Misconceptions In Particle Dynamics, Gang Liu

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The present dissertation research examined the effects of applying the enhanced hands-on intervention to reveal and correct student misunderstandings of the concepts in engineering dynamics, especially particle dynamics. We involved 36 student volunteers for three different research topics. The student participants were divided into two groups in each research topic: enhanced hands-on intervention and pure textbook groups. An interview and intervention was conducted with each participant individually.

The author introduced the “Think-Aloud” method with two kinds of interventions mentioned above. The participants were required to speak out their thought process loud as they worked on the two sets of assessment …

Emergent Phenomena In Quantum Critical Systems, Kun Chen

Doctoral Dissertations

A quantum critical point (QCP) is a point in the phase diagram of quantum matter where a continuous phase transition takes place at zero temperature. Low-dimensional quantum critical systems are strongly correlated, therefore hosting nontrivial emergent phenomena. In this thesis, we first address two decades-old problems on quantum critical dynamics. We then reveal two novel emergent phenomena of quantum critical impurity problems. In the first part of the thesis, we address the linear response dynamics of the $(2+1)$-dimensional $O(2)$ quantum critical universality class, which can be realized in the ultracold bosonic system near the superfluid (SF) to Mott insulator (MI) …

Vegetation Land Cover/Use Dynamics And Their Effects In Mbulu And Karatu Districts In The North-Eastern Highlands Of Tanzania, Leonia John Raphael

International Journal of Geospatial and Environmental Research

Vegetation Land Cover/Land Use dynamics (VLC/LU) are the result of complex and compound interactions between the human (cultural, socioeconomic, and political) and the physical environment at different spatial scales. The present study assesses the spatial distribution of VLC/LU dynamics from 1987 to 2015 in the North-Eastern highlands of Tanzania using both qualitative (in-depth interviews and focus group discussions) and quantitative techniques (spatio-temporal analysis through GIS). The qualitative approach was used to elicit information on the main drivers of VLC/LU changes by land users as transitions occurred with time. The spatio-temporal analysis was used to assess the systematic vegetation land losses, …

Diagnostic Tests For Homoskedasticity In Spatial Cross-Sectional Or Panel Models, Badi H. Baltagi, Alain Pirotte, Zhenlin Yang

Research Collection School Of Economics

We propose tests for homoskedasticity in spatial econometric models, based on joint or concentrated score functions and an Outer-Product-of-Martingale-Difference (OPMD) estimate of the variance of the joint or concentrated score functions. Versions of these tests robust against non-normality are also given. Asymptotic properties of the proposed tests are formally examined using a cross-section model and a panel model with fixed effects. Monte Carlo results show that the proposed tests based on the concentrated score function have good finite sample properties. Finally, the generality of the proposed approach in constructing tests for homoskedasticity is further demonstrated using a spatial dynamic panel …

Modulation Of Cloud Cluster Propagation By Super Cloud Clusters, Joaquin Esteban Blanco

Open Access Dissertations

A series of symmetric, aquachannel simulations obtained with the WRF model are used to study the propagation of tropical Cloud Clusters (CCs) in association with eastwardmoving Super Cloud Clusters (SCCs). The analysis is carried out using the precipitation field in time-longitude coordinates. Two independent but complementary methods are used: the first, from a local approach, involves a CC-tracking algorithm, while the second uses Lagrangian Trajectories in a non-local framework. It is found that the background flow in low-to-mid-levels advects the CCs either eastward or westward depending on model climatology, proximity to the SCC axis, and latitude. Moreover, for most analyzed …

Investigation Of Structure And Dynamics Of Deep Eutectic Solvent Using Infrared Spectroscopy, Yaowen Cui

LSU Doctoral Dissertations

Deep Eutectic Solvents (DES) are liquid mixtures prepared from solids. As a new class of green solvents, DES not only share many properties with ionic liquids, such as low volatility, conductivity, tailorable constituents, but also have some advantages over ionic liquids, like easier preparation, safe and inexpensive materials, biodegradability, low toxicity, and excellent solubility. Because of those attractive properties, DES has been studied in many scientific and engineering fields. However, compared with the great number of studies of the application, many questions about structure and dynamics of DES are unanswered. To shed light on the mystery of solvent or solvation …

Scalable, Hydrophobic And Highly-Stretchable Poly(Isocyanurate-Urethane) Aerogels, Sadeq Malakooti, Saman Rostami, Habel Gitogo Churu, Huiyang Luo, Jenna Clark, Fabiola Casarez, Owen Rettenmaier, Soheil Daryadel, Majid Minary-Jolandan, Chariklia Sotiriou-Leventis, Nicholas Leventis, Hongbing Lu

Chemistry Faculty Research & Creative Works

Scalable, low-density and flexible aerogels offer a unique combination of excellent mechanical properties and scalable manufacturability. Herein, we report the fabrication of a family of low-density, ambient-dried and hydrophobic poly(isocyanurate-urethane) aerogels derived from a triisocyanate precursor. The bulk densities ranged from 0.28 to 0.37 g cm^-3 with porosities above 70% v/v. The aerogels exhibit a highly stretchable behavior with a rapid increase in the Young's modulus with bulk density (slope of log-log plot > 6.0). In addition, the aerogels are very compressible (more than 80% compressive strain) with high shape recovery rate (more than 80% recovery in 30 s). Under …

Elementary Computational Fluid Dynamics Using Finite-Difference Methods, Jason Turner, Scott Labrake

Honors Theses

Fluids permeate all of human existence, and fluid dynamics serves as a rich field of research for many physicists. Although the mathematics involved in studying fluids tends to get complicated, the physical intuition gained through daily exposure to such systems bridges the gap between abstract calculations and their physical meaning. We discuss the mathematical treatment and simulations of fluid flows found in everyday life, such as flow in a cavity and through a pipe. Our discussions follow the example set by several notable texts, referenced in the document.

The Effect Of Warmer Winters On The Demography Of An Outbreak Insect Is Hidden By Intraspecific Competition, Devin W. Goodsman, Guenchik Grosklos, Brian H. Aukema, Caroline Whitehouse, Katherine P. Bleiker, Nate G. Mcdowell, Richard S. Middleton, Chonggang Xu

Mathematics and Statistics Faculty Publications

Warmer climates are predicted to increase bark beetle outbreak frequency, severity, and range. Even in favorable climates, however, outbreaks can decelerate due to resource limitation, which necessitates the inclusion of competition for limited resources in analyses of climatic effects on populations. We evaluated several hypotheses of how climate impacts mountain pine beetle reproduction using an extensive 9‐year dataset, in which nearly 10,000 trees were sampled across a region of approximately 90,000 km², that was recently invaded by the mountain pine beetle in Alberta, Canada. Our analysis supports the hypothesis of a positive effect of warmer winter temperatures on …

Uncovering Newton's Laws Within A Game Of Tug-Of-War, Roberto C. Perez-Franco

University Honors Theses

Introductory physics students frequently struggle with the application of Newton's laws of motion. Students frequently misinterpret Newton's 3^rd Law, which states that for every action there is an equal and opposite reaction. The confusion arises when allocating the action-reaction force pair to a system; students think that the force pair act on the same object, but the force pair actually act on different objects. One interesting example, where action-reaction force pairs come into play, is the game of Tug-of-War. Therefore, to address some misconceptions about Newton's laws of motion, we implemented an activity where we looked at how the …

The Performance Of Quadrilateral Element With Rotational Degrees Of Freedom In Statics And Dynamics Analysis And Optimization, Xingzhi Wang

Mechanical and Aerospace Engineering Theses

Finite Element Method (FEM) is widely used in structural analysis, and the standard approach to increase the accuracy of analysis is increasing the total degrees of freedom (DOFs), namely, refine the mesh. By introducing the rotational DOFs, better accuracy can be achieved without change the mesh. The objective of this study was to investigate the performance of elements with rotational DOFs in statics and dynamics analysis and applying these elements to optimization. The implementation of three representative elements with rotational DOFs for statics analysis is reproduced. Also, this work implements these elements to dynamics analysis and optimization. The results show …

Aperture Passability Judgments In Novice Walker Users: The Impact Of Action Scaling Above And Beyond Body Scaling, Katie Lucaites

All Theses

Many older adults who use assistive walking devices to improve stability and locomotion also report falls while using their device. The present study investigated how walking devices alter the perception-action system of the user. Specifically, the study assessed how walker users perceive their ability to pass through a doorway. One’s ability to pass through an aperture is constrained by their widest frontal dimension (body-scaling) and the dynamic properties of the individual in motion (action-scaling). In order to compare the unique impacts of body-scaling and action-scaling, novice users of a standard walker, wheeled walker, cane, or no device (control) made static …

A New Adaptive Multiscale Approach For The Dynamic Modeling And Simulation Of Biomolecular Systems, Ashley Chase Guy

Mechanical and Aerospace Engineering Dissertations

This dissertation presents three developments in the simulation of sub-micron dynamical systems. First, a new thermostat formulation is shown to strictly enforce the constant temperature constraint necessary in many thermodynamic ensembles. This formulation also allows the system to quickly evolve to a low-potential state. Next, this new thermostat formulation is leveraged to extend a continuum-regime multiscale formulation to the atomistic regime allowing for equivalent time histories to be generated in significantly less computation time. Finally, an adaptive multiscale formulation allows for potential forces with time varying magnitudes to contribute to the overall dynamics similarly resulting in equivalent time histories in …

Dynamics And Control Of Jumping Legged Robot, Gurashish Singh

Mechanical and Aerospace Engineering Theses

This research aims to studying the agility of legged robots particularly their interactions with the ground and achieve a jumping motion by using an operational space controller. Methods were developed to first formulate the equations of motions of the full system. Then we used the published impact and contact analytical framework to detect simultaneous, indeterminate impact and transition to contact with friction and addressed the well-known issues with energy consistency when using rigid body models for dynamic systems (i.e. there are no unusual gains in the energy after impact has ended). Non-penetration of the ground was achieved through online constraint …

A Generative Model Of The Mutual Escalation Of Anxiety Between Religious Groups, F. Leron Shults, Ross Gore, Wesley J. Wildman, Christopher J. Lynch, Justin E. Lane, Monica D. Toft

VMASC Publications

We propose a generative agent-based model of the emergence and escalation of xenophobic anxiety in which individuals from two different religious groups encounter various hazards within an artificial society. The architecture of the model is informed by several empirically validated theories about the role of religion in intergroup conflict. Our results identify some of the conditions and mechanisms that engender the intensification of anxiety within and between religious groups. We define mutually escalating xenophobic anxiety as the increase of the average level of anxiety of the agents in both groups overtime. Trace validation techniques show that the most common conditions …

Mathematical Modelling Of The Rotor-Driven Revolving Vane Compressor With Fixed Vane (Rv-I) With Consideration Of The Vane Thickness, Alison Subiantoro, Kim Tiow Ooi

International Compressor Engineering Conference

The rotor-driven revolving vane compressor with a fixed vane (RV-I compressor) was introduced in 2008. It has been shown to exhibit superior mechanical performance as compared to conventional rotary compressors and the original revolving vane compressor design due to its unique cylinder-rotor arrangement. In such a machine, both the rotor and the cylinder rotate together with the help of the vane, resulting in significantly reduced frictional losses. Mathematical models had been developed and validated to simulate the characteristics of RV-I compressors. These models typically assumed negligible vane thickness to simplify the analysis. In this paper, a new mathematical model for …

Dynamic Simulation Of The Cad Model In Simmechanics With Multiple Uses, Jiri Zátopek, Zdenek Ú?Ední?Ek, José Machado, João Sousa

Turkish Journal of Electrical Engineering and Computer Sciences

When designing a mechatronic system, several steps are taken into account. One of the main steps is the design of a CAD model representing the physical part of the system, and another major point is the development of the mathematical model necessary for the respective controller design. This paper combines both design steps and shows the advantages of using this approach. First, a CAD model is created considering the kinematic and dynamic behavior of the system as well as respective material properties. This CAD model is, in parallel, used for both purposes: as the main basis for developing a mathematical …

Airborne Doppler Radar Observations Of Pyrocu/Cb Plume Kinematics And Thermodynamics During The 2016 Pioneer Fire, Bruno Rodriguez

Master's Theses

During a period of explosive growth of the Pioneer Fire (Idaho, August 2016), deep pyroconvective plumes were sampled by aircraft. The research aircraft was equipped with both remote sensing and in situ instrumentation, including a W-Band Doppler radar which provided high-resolution vertical velocity retrievals from within the developing pyrocumulus. Being the first direct observations of vertical velocity within a pyrocumulus cloud, they have provided unique insights into the dynamical processes governing pyroconvective environments, with important implications for the fire modeling community. The observations were quality-controlled and corrected for issues such as Doppler velocity aliasing, and the plume’s kinematic structure was …

Introducing Statistical Persistence Decay – A Quantification Of Stride-To-Stride Time Interval Dependency In Human Gait, P. C. Raffalt, J. M. Yentes

Journal Articles

Stride-to-stride time intervals during human walking are characterised by predictability and statistical persistence quantified by sample entropy (SaEn) and detrended fluctuation analysis (DFA) which indicates a time dependency in the gait pattern. However, neither analyses quantify time dependency in a physical or physiological interpretable time scale. Recently, entropic half-life (ENT½) has been introduced as a measure of the time dependency on an interpretable time scale. A novel measure of time dependency, based on DFA, statistical persistence decay (SPD), was introduced. The present study applied SaEn, DFA, ENT½, and SPD in known theoretical signals (periodic, chaotic, and random) and stride-to-stride time …

Dynamics Study Of The Hermetic Compressor, Simone Penazzo

International Compressor Engineering Conference

In this Paper a detailed study of dynamics of the hermetic compressor is shown. The key point of this study is the well-known issue of compressor reciprocating kinematic unbalancing which is the main cause of modern refrigerator structural vibrations and consequently acoustical performance. In this frame-work the main target of this work is the reduction and redistribution of compressor accelerations along “privileged” axes to reduce the aforementioned phenomena. Starting from the general treatment of Professor Sōdel, specific studies on reciprocating kinematic balancing, discharge pipe, suspension springs and crankcase dynamics are performed. In particular, a detailed model is developed to calculate …