Thermal Buckling of Plates and Shells

1993 ◽  
Vol 46 (10) ◽  
pp. 485-506 ◽  
Author(s):  
Earl A. Thornton
Keyword(s):  
Experimental Studies ◽  
Composite Plates ◽  
Past Research ◽  
Thermal Buckling ◽  
Future Research ◽  
Shallow Shells ◽  
Conical Shells ◽  
Practical Applications ◽  
Plates And Shells ◽  
Curved Panels

This review discusses research on thermal buckling of plates and shells since the first work in the 1950s. Elastic thermal buckling of metallic as well as composite plates and shells is described. The role of material thermal properties on thickness and spatial temperature gradients is demonstrated first. Then thermal buckling and postbuckling research for plates, shallow shells and curved panels, cylindrical and conical shells is presented. Analytical, computational and experimental studies are described. Governing equations and formulas for critical buckling temperatures are presented for several practical applications. An assessment of past research is made, and future research needs are highlighted.

A review on recent advances and challenges of ionic wind produced by corona discharges with practical applications

2021 ◽  
Author(s):  
Jingguo Qu ◽  
Minjun Zeng ◽  
Dewei Zhang ◽  
Dakai Yang ◽  
Xiongwei Wu ◽  
...  
Keyword(s):  
Corona Discharge ◽  
Experimental Studies ◽  
Wind Generation ◽  
Future Research ◽  
Discharge Process ◽  
Ionic Wind ◽  
Practical Applications ◽  
Wind Generators ◽  
Wide Range ◽  
Gas Ionization

Abstract Ionic wind, an induced phenomenon during corona discharge, possessing the features of silent operation and no moving parts, has a wide range of applications. Ionic wind generation is accompanied by complex physical processes, involving gas ionization, ion recombination, flow, and various chemical reactions, as well as mutual couplings between some of them. Therefore, understanding the corona discharge process and ionic wind generation is crucial for researchers and engineers to better utilize this phenomenon in practical applications. In this review, the principles of corona discharge and its induced ionic wind are presented. Subsequently, ionic wind generators (IWGs) are discussed according to their applications, and the corresponding advances based on experimental studies and numerical simulations are also reviewed. Moreover, the challenges of transitioning the ionic wind technology from laboratory studies to practical applications are discussed. These challenges include the excessively high onset voltage of the corona, ozone emission, and influence of environmental conditions. Furthermore, the mechanisms of these barriers and several effective approaches for mitigating them are provided. Finally, some future research prospects and the conclusions are presented.

Recent Advances in Computational Thermostructural Analysis of Composite Plates and Shells With Strong Nonlinearities

1997 ◽  
Vol 50 (5) ◽  
pp. 285-306 ◽  
Author(s):  
John Argyris ◽  
Lazarus Tenek
Keyword(s):  
High Temperature ◽  
Structural Engineering ◽  
Laminated Composite ◽  
Composite Plates ◽  
Future Research ◽  
Current State ◽  
High Temperature Materials ◽  
Plates And Shells ◽  
Triangular Elements ◽  
Very High

The article presents some modern developments in computational technology for the nonlinear thermostructural analysis of laminated composite plates and shells of arbitrary geometry. Following a review of the current state of the art, it particularly emphasizes on new finite element methodologies that can be applied to the study of complex laminated shells both thermally and structurally using the same topology constructed via simple simplex triangular elements based on respective first-order lamination theories. Very high temperatures are imposed on some examples in order to demonstrate the high effect of nonlinearity. In addition, the authors want to prepare the ground for the advent of new high-temperature materials. For the numerical examples presented comparison with reference solutions is made where available. Thus the present overview intends to impact a continuing discussion on the unification and integration of thermal and structural analyses methods as they apply to large and complex high-temperature composite shell structures under combined thermal and mechanical loading. In this respect it also intends to contribute to the on-going efforts of integrating thermal and structural engineering codes and the development of suitable interfaces. Future research trends are also identified.

scholarly journals Non-avian reptile learning 40 years on: advances and promising new directions

2019 ◽  
Author(s):  
Birgit Szabo ◽  
Daniel W.A. Noble ◽  
Martin Whiting
Keyword(s):  
Social Learning ◽  
Experimental Studies ◽  
Group Living ◽  
Past Research ◽  
Model Systems ◽  
Learning Ability ◽  
Future Research ◽  
Cognitive Ecology ◽  
Research Areas ◽  
Literature Base

Recently, there has been a surge in cognition research using non-avian reptile systems. As a diverse group of animals, non-avian reptiles (turtles, the tuatara, crocodilians, and squamates - lizards, snakes and amphisbaenids) are good model systems for answering questions related to cognitive ecology; from the role of the environment in impacting brain, behaviour and learning, to how social and life-history factors correlate with learning ability. Furthermore, given their variable social structure and degree of sociality, studies on reptiles have demonstrated that group living is not a pre-condition for social learning. Past research has undoubtedly demonstrated that non-avian reptiles are capable of more than just instinctive reactions and basic cognition. Despite their ability to provide answers to fundamental questions in cognitive ecology, and a growing literature base, there have been no systematic syntheses of research in this group. Here, we systematically, and comprehensively review studies on reptile learning. We identify 92 new studies investigating learning in reptiles not included in previous reviews on the same topic – affording a unique opportunity to provide a more in-depth synthesis of existing work, its taxonomic distribution, the types of cognitive domains tested and methodology that has been used. Our review therefore provides a major update on our current state of knowledge and ties the collective evidence together under nine umbrella research areas: (1) habituation, (2) conditioning, (3) aversion learning, (4) spatial learning, (5) learning during foraging, (6) numerical competency, (7) learning flexibility, (8) problem solving, and (9) social learning. Importantly, we identify knowledge gaps and propose themes which offer important future research opportunities including how cognitive ability might influence fitness and survival, testing cognition in ecologically relevant situations, comparing cognition in invasive and non-invasive populations of species, and social learning. To move the field forward, it will be immensely important to build upon the descriptive approach of testing if a species can learn a task with experimental studies elucidating causal reasons for cognitive variation within and between species. With the appropriate methodology, this young but rapidly growing field of research should advance greatly in the coming years providing significant opportunities for addressing general questions in cognitive ecology and beyond.

scholarly journals A ‘Speed—Difficulty—Accuracy’ Model Following a General Trajectory Motor Task with Spatial Constraints: An Information-Based Model

2020 ◽  
Vol 10 (21) ◽  
pp. 7516
Author(s):  
Salvatore Digiesi ◽  
Andrea Lucchese ◽  
Carlotta Mummolo
Keyword(s):  
Field Experiments ◽  
Experimental Studies ◽  
Motor Task ◽  
Research Field ◽  
Future Research ◽  
Motor Tasks ◽  
Task Execution ◽  
General Validity ◽  
Practical Applications ◽  
Speed Accuracy

Accuracy in executing a motor task, i.e., in following a given trajectory under geometrical constraints, is of great interest in work operations as well as in biomechanics applications. In the framework of the Fitts’ law research on motor tasks, experimental studies usually refer to simple trajectories which are of low interest in practical applications. Furthermore, available models lack predicting accuracy in executing motor tasks since do not systematically investigate effects of both speed and task difficulty (index of difficulty (ID)). In this paper, the authors propose a ‘Speed-ID-Accuracy’ model aiming at overcoming abovementioned limits. The model is of general validity as is based on an information-based formulation of a trajectory ID; the model proposed put into relation accuracy in task execution with a general trajectory and with the speed of task execution. Modeling accuracy, defined as standard deviation of the endpoint position, is carried out by regressing data available in the literature. The model proposed proves to be more accurate than the classical ‘Speed-Accuracy’ model in fitting available data. Such a result has been found in both numerical cases relating to ‘tunnel’ and ‘circular’ traveling tasks. Limits of data from field experiments are stressed out and future research field of investigations in work environment and biomechanics are figured out.

RECLAMATION AND CULVERT CROSSINGS MADE OF CORRUGATED PIPES ON SPAWNING STREAMS

2020 ◽  
pp. 68-77
Author(s):  
O.N. CHERNYKH ◽  
◽  
A.V. RBURLACHENKO
Keyword(s):  
Single Point ◽  
Experimental Studies ◽  
Fish Passage ◽  
Future Research ◽  
Fish Stocks ◽  
Metal Structures ◽  
Natural Reproduction ◽  
Spiral Shape ◽  
Corrugated Metal ◽  
Spawning Streams

Recommendations are presented for solving issues that arise in the design and operation of tubular transport crossings of corrugated metal structures through spawning streams while ensuring the safety and natural reproduction of fish stocks. There are discussed the results of experimental studies of culverts made of metal corrugated pipes with a normal and spiral shape of corrugation the bottom of which is buried and filled with suitable granular material to the level of the natural channel of a small watercourse. It is established that when 10% of the area of the corrugated pipe is occupied by stone filling, its throughput is reduced by about 10-12%. Based on the review of the existing literature and the results of laboratory experiments, data is provided to estimate the values of the roughness coefficients of the composite cross-section of a single-point junction and directions for future research on culvert reclamation are outlined. Studying of the structure of the velocity distribution in culverts can lead to the improved conditions for fish passage without installing special structural elements in the transit path of the fish passage structure.

Diagnostics of metal samples using the results of experimental and theoretical study of positively charged microparticles formed upon sample destruction

2018 ◽  
Vol 84 (10) ◽  
pp. 23-28
Author(s):  
D. A. Golentsov ◽  
A. G. Gulin ◽  
Vladimir A. Likhter ◽  
K. E. Ulybyshev
Keyword(s):  
Experimental Data ◽  
Early Stage ◽  
Experimental Studies ◽  
Material Model ◽  
Total Charge ◽  
Cross Sectional ◽  
Practical Applications ◽  
Mechanical And Electrical Properties ◽  
Order Of Magnitude ◽  
Using Data

Destruction of bodies is accompanied by formation of both large and microscopic fragments. Numerous experiments on the rupture of different samples show that those fragments carry a positive electric charge. his phenomenon is of interest from the viewpoint of its potential application to contactless diagnostics of the early stage of destruction of the elements in various technical devices. However, the lack of understanding the nature of this phenomenon restricts the possibility of its practical applications. Experimental studies were carried out using an apparatus that allowed direct measurements of the total charge of the microparticles formed upon sample rupture and determination of their size and quantity. The results of rupture tests of duralumin and electrical steel showed that the size of microparticles is several tens of microns, the particle charge per particle is on the order of 10–14 C, and their amount can be estimated as the ratio of the cross-sectional area of the sample at the point of discontinuity to the square of the microparticle size. A model of charge formation on the microparticles is developed proceeding from the experimental data and current concept of the electron gas in metals. The model makes it possible to determine the charge of the microparticle using data on the particle size and mechanical and electrical properties of the material. Model estimates of the total charge of particles show order-of-magnitude agreement with the experimental data.

Amruthapala (Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter): A Comprehensive Review on Diversity, Therapeutic Uses, and Valorization of Bioactive Constituents

2019 ◽  
Vol 20 (5) ◽  
pp. 376-389 ◽  
Author(s):  
Sonali Mishra ◽  
Nupur Srivastava ◽  
Velusamy Sundaresan ◽  
Karuna Shanker
Keyword(s):  
Secondary Metabolite ◽  
Current Knowledge ◽  
Experimental Studies ◽  
Critical Discussion ◽  
Future Research ◽  
Bioactive Constituents ◽  
Medicinal Uses ◽  
Comprehensive Review ◽  
Therapeutic Uses ◽  
Decalepis Arayalpathra

Background: Decalepis arayalpathra (J. Joseph and V. Chandras.) Venter is used primarily for nutrition besides its therapeutic values. Traditional preparations/formulations from its tuber are used as a vitalizer and blood purifier drink. The folklore medicinal uses cover inflammation, cough, wound healing, antipyretic, and digestive system management. A comprehensive review of the current understanding of the plant is required due to emerging concerns over its safety and efficacy. Objective: The systematic collection of the authentic information from different sources with the critical discussion is summarised in order to address various issues related to botanical identity, therapeutic medicine, nutritional usage, phytochemical, and pharmacological potentials of the D. arayalpathra. Current use of traditional systems of medicine can be used to expand future research opportunities. Materials and Methods: Available scripted information was collected manually, from peered review research papers and international databases viz. Science Direct, Google Scholar, SciFinder, Scopus, etc. The unpublished resources which were not available in database were collected through the classical books of ‘Ayurveda’ and ‘Siddha’ published in regional languages. The information from books, Ph.D. and MSc dissertations, conference papers and government reports were also collected. We thoroughly screened the scripted information of classical books, titles, abstracts, reports, and full-texts of the journals to establish the reliability of the content. Results: Tuber bearing vanilla like signature flavor is due to the presence of 2-hydroxy-4-methoxybenzaldehyde (HMB). Among five other species, Decalepis arayalpathra (DA) has come under the ‘critically endangered’ category, due to over-exploitation for traditional, therapeutic and cool drink use. The experimental studies proved that it possesses gastro-protective, anti-tumor, and antiinflammatory activities. Some efforts were also made to develop better therapeutics by logical modifications in 2-Hydroxy-4-methoxy-benzaldehyde, which is a major secondary metabolite of D. arayalpathra. ‘Amruthapala’ offers the enormous opportunity to develop herbal drink with health benefits like gastro-protective, anti-oxidant and anti-inflammatory actions. Results: The plant has the potential to generate the investigational new lead (IND) based on its major secondary metabolite i.e. 2-Hydroxy-4-methoxy-benzaldehyde. The present mini-review summarizes the current knowledge on Decalepis arayalpathra, covering its phytochemical diversity, biological potentials, strategies for its conservation, and intellectual property rights (IPR) status. Chemical Compounds: 2-hydroxy-4-methoxybenzaldehyde (Pubchem CID: 69600), α-amyrin acetate (Pubchem CID: 293754), Magnificol (Pubchem CID: 44575983), β-sitosterol (Pubchem CID: 222284), 3-hydroxy-p-anisaldehyde (Pubchem CID: 12127), Naringenin (Pubchem CID: 932), Kaempferol (Pubchem CID: 5280863), Aromadendrin (Pubchem CID: 122850), 3-methoxy-1,2-cyclopentanedione (Pubchem CID: 61209), p-anisaldehyde (Pubchem CID: 31244), Menthyl acetate (Pubchem CID: 27867), Benzaldehyde (Pubchem CID: 240), p-cymene (Pubchem CID: 7463), Salicylaldehyde (Pubchem CID: 6998), 10-epi-γ-eudesmol (Pubchem CID: 6430754), α -amyrin (Pubchem CID: 225688), 3-hydroxy-4-methoxy benzaldehyde (Pubchem CID: 12127).

Collaborative Remembering in Dementia: A Focus on Joint Activities

2018 ◽  
Author(s):  
Lars-Christer Hydén ◽  
Mattias Forsblad
Keyword(s):  
Everyday Life ◽  
Past Research ◽  
Research Field ◽  
Future Research ◽  
Research Needs ◽  
Joint Activities ◽  
Do So ◽  
Dementia Diseases

In this chapter we consider collaborative remembering and joint activates in everyday life in the case of people living with dementia. First, we review past research of practices that scaffolds the participation of persons with dementia in everyday chores under different stages of dementia diseases. We do so by suggesting three analytical types of scaffolding: when the scaffolding practices (i) frame the activity, (ii) guide actions, or (iii) are part of repair activities. Second, we review two aspects of collaborative remembering that are especially important in the case of dementia: training of scaffolding practices, and the sustaining and presentation of identities through collaborative storytelling. Finally, theoretical and methodological tendencies of the research field are summarized and future research needs are formulated.

scholarly journals The Potential of the Synthetic Strigolactone Analogue GR24 for the Maintenance of Photosynthesis and Yield in Winter Wheat under Drought: Investigations on the Mechanisms of Action and Delivery Modes

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1223
Author(s):  
Mojde Sedaghat ◽  
Yahya Emam ◽  
Ali Mokhtassi-Bidgoli ◽  
Saeid Hazrati ◽  
Claudio Lovisolo ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Foliar Application ◽  
Mechanisms Of Action ◽  
Bioactive Molecules ◽  
Future Research ◽  
Antioxidant Enzyme Activities ◽  
Synthetic Analog ◽  
Practical Applications ◽  
New Family ◽  
Harsh Environmental Condition

Strigolactones (SLs) have been implicated in many plant biological and physiological processes, including the responses to abiotic stresses such as drought, in concert with other phytohormones. While it is now clear that exogenous SLs may help plants to survive in harsh environmental condition, the best, most effective protocols for treatment have not been defined yet, and the mechanisms of action are far from being fully understood. In the set of experiments reported here, we contrasted two application methods for treatment with a synthetic analog of SL, GR24. A number of morphometric, physiological and biochemical parameters were measured following foliar application of GR24 or application in the residual irrigation water in winter wheat plants under irrigated and drought stress conditions. Depending on the concentration and the method of GR24 application, differentiated photosynthesis and transpiration rate, stomatal conductance, leaf water potential, antioxidant enzyme activities and yield in drought conditions were observed. We present evidence that different methods of GR24 application led to increased photosynthesis and yield under stress by a combination of drought tolerance and escape factors, which should be considered for future research exploring the potential of this new family of bioactive molecules for practical applications.

Dating Violence, Protection Orders, and Gender Inequality: A Cross-state Analysis of Policy Formulation and Implementation

2021 ◽  
pp. 088626052110283
Author(s):  
Katherine Brandt ◽  
Michelle Johnson-Motoyama
Keyword(s):  
Dating Violence ◽  
Gender Inequality ◽  
Partner Violence ◽  
Past Research ◽  
Teen Dating Violence ◽  
Policy Formulation ◽  
Future Research ◽  
Health Crisis ◽  
Study Approach ◽  
Teen Dating

Teen dating violence (TDV) is a public health crisis that organizations and individuals in several fields are working to prevent and address. State lawmakers are a group with substantial power to address TDV and intimate partner violence (IPV) through policies including Civil Protection Order (CPO) statutes. Understanding the factors that influence how state legislators craft TDV and IPV policies and how those policies are implemented can lead to policy processes that better serve survivors. Past research suggests the level of gender inequality in a state may be an important influence on TDV policies. This study used a case study approach to compare the processes of adding individuals in dating relationships to CPO statutes in a subset of states ( n = 3) with high, middle, and low levels of gender inequality. Results did not suggest that gender inequality was related to variation between states but rather that it was a larger factor that creates the need for TDV policies at all. Relationships between the state IPV coalitions and lawmakers and the historical moment that laws were considered emerged as important factors in interstate variation. Future research can build on these results by further exploring the role of gender inequality in policy processes with additional states or policies and by examining the factors identified here in greater depth. Implications for practice are also discussed.

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