scholarly journals The structure of the bark of the annual stem of Spiraea beauverdiana (Rosaceae) in the conditions of the solfatar fields of the Golovnin volcano’s caldera (Kunashir, South Kuril Islands)

2021 ◽  
Vol 25 (1) ◽  
Author(s):  
E.O. Vatserionova ◽  
◽  
A.V. Kopanina ◽  
I.I. Vlasova ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Normal Values ◽  
Structural Parameters ◽  
Structural Response ◽  
Stem Bark ◽  
Extreme Conditions ◽  
Bark Thickness ◽  
Pinus Pumila ◽  
Adaptive Nature ◽  
South Kuril Islands

The results of comparative analysis of adaptive features of bark of the Spiraea beauverdiana S.K. Schneid. (Rosaceae Juss.) are presented in the extreme conditions of the Central Eastern solfatara field of the Golovnin volcano’s caldera and typical conditions (pinus pumila-shrub sasa sp.). A statistical analysis of the structural parameters of annual stem S. beauverdiana bark has been conducted, which has made it possible to distinguish features dependent on extreme environmental conditions. Parameters of annual stem bark have been elicited, which have higher than normal values: stem diameter, bark thickness, the thickness of periderm and phellem, radial diameter of phellem cells, lack of biseriate phloem rays. It was found the formation of distinct zones of bark abnormal structures having adaptive character in extreme conditions of solfataric fields. These abnormal zones are characterized by the own line of symmetry, they are sphere-shaped, tissues and cells indices forming these structures massively differ from the same parts with typical structures. The structural response of the annual stem bark of S. beauverdiana is likely to have an adaptive nature.

scholarly journals Structural Reliability Sensitivities under Nonstationary Random Vibrations

2013 ◽  
Vol 2013 ◽  
pp. 1-21 ◽  
Author(s):  
Rita Greco ◽  
Francesco Trentadue
Keyword(s):  
Structural Reliability ◽  
Structural Parameters ◽  
Time Integration ◽  
Structural Response ◽  
Integration Scheme ◽  
Structural Systems ◽  
Frame Building ◽  
Time Integration Scheme ◽  
Noise Input ◽  
The Time Domain

Response sensitivity evaluation is an important element in reliability evaluation and design optimization of structural systems. It has been widely studied under static and dynamic forcing conditions with deterministic input data. In this paper, structural response and reliability sensitivities are determined by means of the time domain covariance analysis in both classically and nonclassically damped linear structural systems. A time integration scheme is proposed for covariance sensitivity. A modulated, filtered, white noise input process is adopted to model the stochastic nonstationary loads. The method allows for the evaluation of sensitivity statistics of different quantities of dynamic response with respect to structural parameters. Finally, numerical examples are presented regarding a multistorey shear frame building.

A Probabilistic High-Pressure Zone Model of Dynamic Ice Structure Interactions and Associated Ice-Induced Vibrations

2021 ◽  
Author(s):  
Ridwan Hossain ◽  
Rocky Taylor ◽  
Lorenzo Moro
Keyword(s):  
High Pressure ◽  
Theoretical Calculations ◽  
Structural Parameters ◽  
Structural Response ◽  
Zone Model ◽  
Modelling Framework ◽  
Lower Amplitude ◽  
Average Strain Rate ◽  
High Pressure Zone ◽  
Lock In

Abstract During ice-structure interactions that are dominated by ice compressive failure, the majority of the ice loads are transmitted through localized contact regions known as high-pressure zones (hpzs). This paper presents a probabilistic modelling framework for dynamic ice-structure interaction based on the mechanics of hpzs. Individual hpzs are modelled as a nonlinear spring-damper system where the stiffness is modelled as a function of nominal strain, with the degree of softening depending on the average strain-rate. Both spalling and crushing failure mechanisms were assessed in the context of periodical sinusoidal response. For spall dominated failure, the model structure showed presence of frequency lock-in in the speed range of 100–125mm/s, beyond which the failure was found to be random in nature with lower amplitude of structural response. The amplitude was also found to be significantly influenced by structural parameters with structural damping having the highest contribution. For pure crushing, an estimated equilibrium layer thickness based on theoretical calculations also showed presence of frequency lock-in. The work highlights the importance of understanding the interplay between these mechanisms, as well as the role of ice conditions and structural parameters on the processes that dominate an interaction.

scholarly journals The putative polysaccharide deacetylase Ba0331: cloning, expression, crystallization and structure determination

2019 ◽  
Vol 75 (4) ◽  
pp. 312-320
Author(s):  
Athena Andreou ◽  
Petros Giastas ◽  
Sofia Arnaouteli ◽  
Mary Tzanodaskalaki ◽  
Socrates J. Tzartos ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Comparative Analysis ◽  
Bacillus Anthracis ◽  
Structure Determination ◽  
Cell Shape ◽  
Catalytic Domain ◽  
Extreme Conditions ◽  
Carbohydrate Esterase ◽  
Type 3 ◽  
Fibronectin Type

Ba0331 is a putative polysaccharide deacetylase from Bacillus anthracis, the etiological agent of the disease anthrax, that contributes to adaptation of the bacterium under extreme conditions and to maintenance of the cell shape. In the present study, the crystal structure of Ba0331 was determined at 2.6 Å resolution. The structure consists of two domains: a fibronectin type 3-like (Fn3-like) domain and a NodB catalytic domain. The latter is present in all carbohydrate esterase family 4 enzymes, while a comparative analysis of the Fn3-like domain revealed structural plasticity despite the retention of the conserved Fn3-like domain characteristics.

Additive manufacturing and mechanical properties of lattice-curved structures

2019 ◽  
Vol 25 (5) ◽  
pp. 895-903 ◽  
Author(s):  
Enrique Cuan-Urquizo ◽  
Mario Martínez-Magallanes ◽  
Saúl E. Crespo-Sánchez ◽  
Alfonso Gómez-Espinosa ◽  
Oscar Olvera-Silva ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fused Deposition Modeling ◽  
Structural Parameters ◽  
Structural Response ◽  
Layered Structures ◽  
Lattice Structures ◽  
Structure Property ◽  
Content Type ◽  
Fused Deposition ◽  
Curved Structures

Purpose The purpose of this paper is to study the feasibility of the fabrication of circle arc curved-layered structures via conventional fused deposition modeling (FDM) with three-axis machines and to identify the main structural parameters that have an influence on their mechanical properties. Design/methodology/approach Customized G-codes were generated via a script developed in MATLAB. The G-codes contain nozzle trajectories with displacements in the three axes simultaneously. Using these, the samples were fabricated with different porosities, and their influence on the mechanical responses evaluated via tensile testing. The load-displacement curves were analyzed to understand the structure-property relationship. Findings Circled arc curved-layered structures were successfully fabricated with conventional three-axis FDM machines. The response of these curved lattice structures under tensile loads was mapped to three main stages and deformation mechanisms, namely, straightening, stretching and fracture. The micro-structure formed by the transverse filaments affect the first stage significantly and the other two minimally. The main parameters that affect the structural response were found to be the transverse filaments, as these could behave as hinges, allowing the slide/rotation of adjacent layers and making the structure more shear sensitive. Research limitations/implications This paper was restricted to arc-curved samples fabricated with conventional three-axis FDM machines. Originality/value The FDM fabrication of curved-structures with controlled porosity and their relation to the resulting mechanical properties is presented here for the first time. The study of curved-lattice structures is of great relevance in various areas, such as biomedical, architecture and aerospace.

scholarly journals Study on collapsibility of typical structural loess by multi-parameter comparative analysis

2021 ◽  
Vol 293 ◽  
pp. 01032
Author(s):  
Liu Hongcheng ◽  
Lu Changwei ◽  
Wang Yinxia ◽  
Song Yi ◽  
Guan Xiangfeng ◽  
...  
Keyword(s):  
Particle Size ◽  
Comparative Analysis ◽  
Moisture Content ◽  
Composite Structure ◽  
Structural Parameters ◽  
Initial Moisture Content ◽  
Clay Content ◽  
Dry Density ◽  
Particle Content ◽  
Multiple Groups

To study the collapsibility of typical loess and its influencing factors in different areas, the samples in Jingyang, Lanzhou and Yili were studied. The correlation between initial moisture content, dry density, composition of particle size, structural parameters and the coefficient of subsidence is analyzed. The results show that: the coefficient of collapsibility is negatively correlated with the initial moisture content and dry density. In the experiments of multiple groups, the collapsibility coefficient has a certain correlation with the clay content, but not a uniform correlation with the particle content. The collapse coefficient is approximately positively correlated with the composite structure potential.

scholarly journals Comparative Analysis of Knits from Peat Fibre and its Combinations with Other Natural Fibres

2017 ◽  
Vol 25 (0) ◽  
pp. 24-29
Author(s):  
Daiva Mikučioniené ◽  
Lina Čepukonė
Keyword(s):  
Comparative Analysis ◽  
Physical Properties ◽  
Water Adsorption ◽  
Structural Parameters ◽  
Air Permeability ◽  
Raw Material ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Natural Origin ◽  
Mechanical And Physical Properties

Natural and man-made fibres of natural origin are more and more widely used, while consideration of sustainability is constantly increasing. The properties and processing behaviour of newly introduced fibres of natural origin are usually compared and often predicted on the basis of widely investigated fibres; however, this prediction sometimes does not have any confirmed basis. Structural parameters and the majority of mechanical and physical properties of knitted fabrics depend on technical characteristics of the knitting machine, on the properties of yarns as well as on the origin of the raw material. This study attempts to develop knits from new natural peat fibres and their combination with widely used woollen, cotton and elastomeric Lycra yarns and to investigate the influence of peat fibre’s nature on structural parameters such as loop length, wale and course spacing, area density, the tightness factor and on main physical properties such as dimensional stability, air permeability and water adsorption.

Unlocking the Physics of Hypervelocity Impact

2013 ◽  
Author(s):  
Andrew Thurber ◽  
Javid Bayandor
Keyword(s):  
Fluid Dynamics ◽  
Finite Element Analysis ◽  
Failure Modes ◽  
Structural Response ◽  
Hypervelocity Impact ◽  
Extreme Conditions ◽  
Strain Rates ◽  
Element Analysis ◽  
Standard Material ◽  
Hypervelocity Impacts

Satellites and spacecraft in orbit can impact micrometeorites and other debris at velocities exceeding thousands of meters per second. The shock pressures and temperatures created by these hypervelocity impacts greatly surpass standard material strengths, and deform structures in unconventional failure modes. Under these extreme conditions and strain rates, plastic deformation of a solid can resemble viscous fluidic motion. Using meshless finite element analysis methods, the present research attempts to quantify this fluidic structural response and identify analogous interactions in fluid dynamics.

COMPARATIVE EVALUATION OF EFFICIENCY AND HYDRODYNAMICS APPLICATION OF THE WASTE OF THE PRODUCTION OF ALUMINIUM AND ALUMINIUMCONTAINED REAGENTS FOR WASTEWATER TREATMENT

2013 ◽  
Vol 3 (4S) ◽  
pp. 100-104
Author(s):  
Elena V YAKOVLEVA
Keyword(s):  
Wastewater Treatment ◽  
Comparative Analysis ◽  
Comparative Evaluation ◽  
Structural Parameters ◽  
Operating Parameters ◽  
Selection Of

The article shows the comparative analysis of the application of sludge hydroaluminatof sodium and famous coagulants for purifi cation of chemical contaminated wastewater, trial coagulating chemical contaminated wastewater plant Rostselmash, comparative selection of the type coagulant ranking on equivalent per cent of operating parameters, according to the Kamps criterionchecking hydrodynamic and structural parameters of the cameras fl occulation with the paddle mixers required.

Psychological features of military personnell with different specifications of negative consequences of staying in extreme conditions of military situation

2020 ◽  
Vol 5 (2) ◽  
pp. 165-182
Author(s):  
Marina Kovaleva
Keyword(s):  
Comparative Analysis ◽  
Environmental Factors ◽  
Empirical Study ◽  
Military Personnel ◽  
Deviant Behavior ◽  
Extreme Conditions ◽  
Gambling Addiction ◽  
Negative Consequences ◽  
Psychological Structure ◽  
Psychological Features

The article presents the results of an empirical study devoted to identifying and describing averaged typical psychological features of categories of military personnel performing combat missions in extreme combat conditions, predisposed to the formation of various forms of deviant behavior as negative consequences of a collision with stressful environmental factors. The results of a comparative analysis of respondents prone to such forms of behavioral deviations as victimization, gambling addiction, procrastination, psychological abuse and violation of official discipline are presented. It was shown that there are statistically significant differences between the psychological structure of these groups of respondents.

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