scholarly journals Study of Magnetic Rotation in 193Pb: An Example of Collaboration Between Southeastern European Research Teams

2020 ◽  
Vol 13 ◽  
pp. 128
Author(s):  
D. L. Balabanski
Keyword(s):  
Experimental Studies ◽  
Theoretical Models ◽  
Magnetic Rotation ◽  
European Research ◽  
Research Teams ◽  
The Balkans ◽  
Scientific Potential ◽  
Stringent Test

This paper summarizes the results of a series of experimental studies of mag­netic rotation in mid-shell Pb nuclei. The focus is for the 29/2- v(1i^3/2)^{-1} (x) π(3s1/2)^{-2}(1h9/2)(i13/2) magnetic band in 193Pb, for which all experimental observables have been measured. This provides a stringent test of the theoretical models aiming at the description of such excitations. These studies have been carried out in col­ laboration with different research teams from the Balkans and are an example how to utilize most efficiently the huge scientific potential of the region.

A Relativistic Newtonian Mechanics Predicts with Precision the Results of Recent Neutrino-Velocity Experiments

2014 ◽  
Vol 6 (1) ◽  
pp. 1032-1035 ◽  
Author(s):  
Ramzi Suleiman
Keyword(s):  
Null Hypothesis ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Newtonian Mechanics ◽  
Speed Of Light ◽  
Symmetry Principle ◽  
Proposed Model ◽  
Significant Difference ◽  
The One ◽  
Complete Collapse

The research on quasi-luminal neutrinos has sparked several experimental studies for testing the "speed of light limit" hypothesis. Until today, the overall evidence favors the "null" hypothesis, stating that there is no significant difference between the observed velocities of light and neutrinos. Despite numerous theoretical models proposed to explain the neutrinos behavior, no attempt has been undertaken to predict the experimentally produced results. This paper presents a simple novel extension of Newton's mechanics to the domain of relativistic velocities. For a typical neutrino-velocity experiment, the proposed model is utilized to derive a general expression for . Comparison of the model's prediction with results of six neutrino-velocity experiments, conducted by five collaborations, reveals that the model predicts all the reported results with striking accuracy. Because in the proposed model, the direction of the neutrino flight matters, the model's impressive success in accounting for all the tested data, indicates a complete collapse of the Lorentz symmetry principle in situation involving quasi-luminal particles, moving in two opposite directions. This conclusion is support by previous findings, showing that an identical Sagnac effect to the one documented for radial motion, occurs also in linear motion.

scholarly journals Experimental Evaluation of Airlift Performance for Vertical Pumping of Water in Underground Mines

2021 ◽  
Author(s):  
Parviz Enany ◽  
Oleksandr Shevchenko ◽  
Carsten Drebenstedt
Keyword(s):  
Water Flow ◽  
High Efficiency ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Injection System ◽  
Experimental Investigations ◽  
Flow Mode ◽  
New Device ◽  
Riser Pipe ◽  
Airlift Pump

AbstractThis paper presents experimental studies on the optimization of air–water flow in an airlift pump. Airlift pumps use compressed gas to verticall transport liquids and slurries. Due to the lack of theoretical equations for designing and predicting flow regimes, experimental investigations must be carried out to find the best condition to operate an airlift pump at high efficiency. We used a new air injection system and different submergence ratios to evaluate the output of a simple pump for vertical displacement of water in an underground mine. The tests were carried out in a new device with 5.64 m height and 10.2 cm circular riser pipe. Three air-jacket pipes, at different gas flows in the range of 0.002–0.09 m3/s were investigated with eight submergence ratios. It was found that with the same air flow rate, the most efficient flow of water was achieved when an air jacket with 3 mm diameter holes was used with a submergence ratio between 0.6 and 0.75. In addition, a comparison of practical results with two theoretical models proposed by other investigators showed that neither was able to accurately predict airlift performance in air–water flow mode.

A Review of Theoretical and Experimental Research on Various Autofrettage Processes

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Rajkumar Shufen ◽  
Uday S. Dixit
Keyword(s):  
Experimental Studies ◽  
Theoretical Models ◽  
Pressure Vessels ◽  
Future Research ◽  
Spherical Vessel ◽  
Considerable Research ◽  
Wide Range ◽  
Set Up ◽  
Compressive Residual Stresses ◽  
Spherical Pressure

Autofrettage is a metal forming technique widely incorporated for strengthening the thick-walled cylindrical and spherical pressure vessels. The technique is based on the principle of initially subjecting the cylindrical or spherical vessel to partial plastic deformation and then unloading it; as a result of which compressive residual stresses are set up. On the basis of the type of the forming load, autofrettage can be classified into hydraulic, swage, explosive, thermal, and rotational. Considerable research studies have been carried out on autofrettage with a variety of theoretical models and experimental methods. This paper presents an extensive review of various types of autofrettage processes. A wide range of theoretical models and experimental studies are described. Optimization of an autofrettage process is also discussed. Based on the review, some challenging issues and key areas for future research are identified.

scholarly journals Cooperation among Tumor Cell Subpopulations Leads to Intratumor Heterogeneity

2020 ◽  
Vol 15 (02) ◽  
pp. 99-119
Author(s):  
Xin Li ◽  
D. Thirumalai
Keyword(s):  
Tumor Heterogeneity ◽  
Evolutionary Game ◽  
Experimental Studies ◽  
Evolutionary Model ◽  
Theoretical Models ◽  
Intratumor Heterogeneity ◽  
Clear Understanding ◽  
Physical And Mathematical Models

Heterogeneity is a hallmark of all cancers. Tumor heterogeneity is found at different levels — interpatient, intrapatient, and intratumor heterogeneity. All of them pose challenges for clinical treatments. The latter two scenarios can also increase the risk of developing drug resistance. Although the existence of tumor heterogeneity has been known for two centuries, a clear understanding of its origin is still elusive, especially at the level of intratumor heterogeneity (ITH). The coexistence of different subpopulations within a single tumor has been shown to play crucial roles during all stages of carcinogenesis. Here, using concepts from evolutionary game theory and public goods game, often invoked in the context of the tragedy of commons, we explore how the interactions among subclone populations influence the establishment of ITH. By using an evolutionary model, which unifies several experimental results in distinct cancer types, we develop quantitative theoretical models for explaining data from in vitro experiments involving pancreatic cancer as well as in vivo data in glioblastoma multiforme. Such physical and mathematical models complement experimental studies, and could optimistically provide new ideas for the design of efficacious therapies for cancer patients.

Fluid Flow Through Randomly Packed Monodisperse Fibers: The Kozeny-Carman Parameter Analysis

1997 ◽  
Vol 119 (1) ◽  
pp. 188-192 ◽  
Author(s):  
O. Rahli ◽  
L. Tadrist ◽  
M. Miscevic ◽  
R. Santini
Keyword(s):  
Fluid Flow ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Experimental Results ◽  
Parameter Analysis ◽  
Flow Through Porous Media ◽  
Aspect Ratios ◽  
A Value ◽  
Flow Through ◽  
Permeability Increase

Experimental studies have been carried out on fluid flow through porous media made up of randomly packed monodisperse fibers. The permeability and the Kozeny-Carman parameter kk are deduced from experimental results. The variations of the permeability increase exponentially with the porosity. The parameter kk is a decreasing function of the porosity ε and tends asymptotically to a value close to that deduced from a modified Ergun relation. The important decrease, observed for small aspect ratios, is certainly an effect of the cut sections of fibers. The results in terms of parameter kk are systematically compared to those deduced from various theoretical models. The variation laws of the parameter kk, deduced from different models, present important discrepancies with our experimental results.

Molecular Movements and Dynamics in Solutions Studied by Fluorescence Depolarization Measurement

1993 ◽  
Vol 58 (2) ◽  
pp. 213-233 ◽  
Author(s):  
Zuzana Limpouchová ◽  
Karel Procházka ◽  
Vlastimil Fidler ◽  
Jiří Dvořák ◽  
Bohumil Bednář
Keyword(s):  
Energy Transfer ◽  
Rotational Diffusion ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Reorientational Motion ◽  
Fluorescence Depolarization ◽  
Time Resolved ◽  
Langevin Model ◽  
Theoretical Predictions ◽  
Media Systems

Theories allowing interpretation of the results of time-resolved polarization spectrofluorimetry in solutions are reviewed and their applicability under various conditions is discussed. For the reorientation of rigid molecules in an isotropic medium, the most frequently employed models are presented, such as rotational diffusion model, the Fokker-Planck-Langevin model, etc. Systems with internal rotation, systems in anisotropic media, systems with a complex electron relaxation and systems with energy transfer are discussed as examples of more complex systems. A special attention is devoted to the polarization fluorimetry of probes bound to/or sorbed at polymer and biopolymer chains. The review focuses on theoretical models of reorientational motion for interpretation of fluorescence anisotropy decays. Experimental studies and computer simulations are discussed only when it is necessary for comparison with theoretical predictions. Complicated models for simultaneous reorientational motion and energy transfer, solvent relaxation, etc., although very important for many applications, exceed the scope of this review and are mentioned only very briefly.

Transport Phenomena Analysis in Proton Exchange Membrane Fuel Cells

2005 ◽  
Vol 127 (12) ◽  
pp. 1363-1379 ◽  
Author(s):  
Hongtan Liu ◽  
Tianhong Zhou ◽  
Ping Cheng
Keyword(s):  
Experimental Investigation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Transport Phenomena ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Transport Processes ◽  
Proton Exchange ◽  
Exchange Membrane

The objective of this review is to provide a summary of modeling and experimental research efforts on transport phenomena in proton exchange membrane fuel cells (PEMFCs). Several representative PEMFC models and experimental studies in macro and micro PEMFCs are selected for discussion. No attempt is made to examine all the models or experimental studies, but rather the focus is to elucidate the macro-homogeneous modeling methodologies and representative experimental results. Since the transport phenomena are different in different regions of a fuel cell, fundamental phenomena in each region are first reviewed. This is followed by the presentation of various theoretical models on these transport processes in PEMFCs. Finally, experimental investigation on the cell performance of macro and micro PEMFC and DMFC is briefly presented.

Biomechanics of Growth, Remodeling, and Morphogenesis

1995 ◽  
Vol 48 (8) ◽  
pp. 487-545 ◽  
Author(s):  
Larry A. Taber
Keyword(s):  
Shape Change ◽  
Experimental Studies ◽  
Cell Movement ◽  
Theoretical Models ◽  
Cellular Level ◽  
Experimental Results ◽  
Future Research ◽  
Cell Sheets ◽  
Biomechanical Models ◽  
Division Cell

This review deals with biomechanical aspects of growth (mass change), remodeling (property change), and morphogenesis (shape change) in living systems. The emphasis is on theoretical models, but relevant experimental results also are discussed. As an aid to the reader, the fundamental biological terms and concepts are defined for the general problem and for each specific topic. At the outset, the processes involved in growth, remodeling, and morphogenesis are described and placed within the context of the evolution of species. Next, some of the analytical methods used in biomechanical models for these processes are presented. Then, applications of these and other techniques to specific systems are discussed, beginning at the cellular level and proceeding upward to the tissue and organ levels. At the cellular level, modeling and experimental studies are reviewed for cell division, cell movement, and pattern formation, and then morphogenetic mechanisms for epithelia (cell sheets) are discussed. At the tissue and organ levels, the musculoskeletal and cardiovascular systems are considered. Several models are described for growth, remodeling, and morphogenesis of bone, and mainly experimental results are examined in the cases of skeletal muscle, the heart, and arteries. Specific topics for the cardiovascular system include hypertrophy, residual stress, atherosclerosis, and embryonic development. Finally, some future research directions are suggested.

scholarly journals Influence of biomass burning vapor wall loss correction on modeling organic aerosols in Europe by CAMx v6.50

2021 ◽  
Vol 14 (3) ◽  
pp. 1681-1697
Author(s):  
Jianhui Jiang ◽  
Imad El Haddad ◽  
Sebnem Aksoyoglu ◽  
Giulia Stefenelli ◽  
Amelie Bertrand ◽  
...  
Keyword(s):  
Air Quality ◽  
Biomass Burning ◽  
Experimental Studies ◽  
Organic Aerosol ◽  
Basis Set ◽  
Reference Scenario ◽  
Air Quality Model ◽  
Quality Model ◽  
The Balkans ◽  
Wall Loss

Abstract. Increasing evidence from experimental studies suggests that the losses of semi-volatile vapors to chamber walls could be responsible for the underestimation of organic aerosol (OA) in air quality models that use parameters obtained from chamber experiments. In this study, a box model with a volatility basis set (VBS) scheme was developed, and the secondary organic aerosol (SOA) yields with vapor wall loss correction were optimized by a genetic algorithm based on advanced chamber experimental data for biomass burning. The vapor wall loss correction increases the SOA yields by a factor of 1.9–4.9 and leads to better agreement with measured OA for 14 chamber experiments under different temperatures and emission loads. To investigate the influence of vapor wall loss correction on regional OA simulations, the optimized parameterizations (SOA yields, emissions of intermediate-volatility organic compounds from biomass burning, and enthalpy of vaporization) were implemented in the regional air quality model CAMx (Comprehensive Air Quality Model with extensions). The model results from the VBS schemes with standard (VBS_BASE) and vapor-wall-loss-corrected parameters (VBS_WLS), as well as the traditional two-product approach, were compared and evaluated by OA measurements from five Aerodyne aerosol chemical speciation monitor (ACSM) or aerosol mass spectrometer (AMS) stations in the winter of 2011. An additional reference scenario, VBS_noWLS, was also developed using the same parameterization as VBS_WLS except for the SOA yields, which were optimized by assuming there is no vapor wall loss. The VBS_WLS generally shows the best performance for predicting OA among all OA schemes and reduces the mean fractional bias from −72.9 % (VBS_BASE) to −1.6 % for the winter OA. In Europe, the VBS_WLS produces the highest domain average OA in winter (2.3 µg m−3), which is 106.6 % and 26.2 % higher than VBS_BASE and VBS_noWLS, respectively. Compared to VBS_noWLS, VBS_WLS leads to an increase in SOA by up to ∼80 % (in the Balkans). VBS_WLS also leads to better agreement between the modeled SOA fraction in OA (fSOA) and the estimated values in the literature. The substantial influence of vapor wall loss correction on modeled OA in Europe highlights the importance of further improvements in parameterizations based on laboratory studies for a wider range of chamber conditions and field observations with higher spatial and temporal coverage.

scholarly journals Investigation Of Water Leakage Through Direct Tension Cracks In Reinforced Concrete Panels

2021 ◽  
Author(s):  
Seyyednezameddin Bozorgzadeh
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Experimental Program ◽  
Direct Tension ◽  
Pressurized Water ◽  
Concrete Panels ◽  
Tension Cracks ◽  
Crack Widths

In this study the leakage of pressurized water through direct tension cracks in reinforced concrete (RC) panels is investigated experimentally. The results of the experiment can contribute to the field from different aspects since not many experimental studies of this kind have been reported in the literature. In this experimental program, three RC panels are subjected to direct tension force in order to form a major crack. The leakage test is then performed on the cracked specimens and the leakage of water through the crack is measured for different crack widths. The collected data consists of reinforcement strains, crack widths and the leakage rate through the cracks. Related theoretical models are compared against the experiment results. These results indicate that the leakage of water through a crack depend on the pressure of the water, cube of the crack width and crack width gradient.

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