scholarly journals Modelling tooth–prey interactions in sharks: the importance of dynamic testing

2016 ◽  
Vol 3 (8) ◽  
pp. 160141 ◽  
Author(s):  
Katherine A. Corn ◽  
Stacy C. Farina ◽  
Jeffrey Brash ◽  
Adam P. Summers
Keyword(s):  
Dynamic Testing ◽  
Testing Device ◽  
Carcharhinus Plumbeus ◽  
Biologically Relevant ◽  
Galeocerdo Cuvier ◽  
Shark Teeth ◽  
Repeated Use ◽  
And Performance ◽  
Predictive Relationship ◽  
Testing Protocols

The shape of shark teeth varies among species, but traditional testing protocols have revealed no predictive relationship between shark tooth morphology and performance. We developed a dynamic testing device to quantify cutting performance of teeth. We mimicked head-shaking behaviour in feeding large sharks by attaching teeth to the blade of a reciprocating power saw fixed in a custom-built frame. We tested three tooth types at biologically relevant speeds and found differences in tooth cutting ability and wear. Teeth from the bluntnose sixgill ( Hexanchus griseus ) showed poor cutting ability compared with tiger ( Galeocerdo cuvier ), sandbar ( Carcharhinus plumbeus ) and silky ( C. falciformis ) sharks, but they also showed no wear with repeated use. Some shark teeth are very sharp at the expense of quickly dulling, while others are less sharp but dull more slowly. This demonstrates that dynamic testing is vital to understanding the performance of shark teeth.

scholarly journals Sports Foods and Dietary Supplements for Optimal Function and Performance Enhancement in Track-and-Field Athletes

2019 ◽  
Vol 29 (2) ◽  
pp. 198-209 ◽  
Author(s):  
Peter Peeling ◽  
Linda M. Castell ◽  
Wim Derave ◽  
Olivier de Hon ◽  
Louise M. Burke
Keyword(s):  
Performance Enhancement ◽  
Evidence Base ◽  
Track And Field ◽  
Supplement Use ◽  
Optimal Function ◽  
Repeated Use ◽  
And Performance ◽  
The Individual ◽  
Health Function ◽  
Specific Scenario

Athletes are exposed to numerous nutritional products, attractively marketed with claims of optimizing health, function, and performance. However, there is limited evidence to support many of these claims, and the efficacy and safety of many products is questionable. The variety of nutritional aids considered for use by track-and-field athletes includes sports foods, performance supplements, and therapeutic nutritional aids. Support for sports foods and five evidence-based performance supplements (caffeine, creatine, nitrate/beetroot juice, β-alanine, and bicarbonate) varies according to the event, the specific scenario of use, and the individual athlete’s goals and responsiveness. Specific challenges include developing protocols to manage repeated use of performance supplements in multievent or heat-final competitions or the interaction between several products which are used concurrently. Potential disadvantages of supplement use include expense, false expectancy, and the risk of ingesting banned substances sometimes present as contaminants. However, a pragmatic approach to the decision-making process for supplement use is recommended. The authors conclude that it is pertinent for sports foods and nutritional supplements to be considered only where a strong evidence base supports their use as safe, legal, and effective and that such supplements are trialed thoroughly by the individual before committing to use in a competition setting.

Numerical and Experimental Assessment of the Highway Arch Viaduct

2015 ◽  
Vol 769 ◽  
pp. 252-259
Author(s):  
Jan Bencat ◽  
Maria Stehlikova ◽  
Milan Skarupa
Keyword(s):  
Dynamic Testing ◽  
Highway Bridges ◽  
Structural Condition ◽  
Traffic Load ◽  
Analytical Models ◽  
Mode Shapes ◽  
Bridge Structure ◽  
Modal Damping ◽  
Bridge Structures ◽  
And Performance

Full–scale dynamic testing of bridge structures can provide valuable information on the service behavior and performance of structures. With the growing interest in the structural condition of highway bridges, dynamic testing can be used as a tool for assessing the integrity of bridges. From the measured dynamic response, induced by instructed passing trucks, modal parameters (natural frequencies, mode shapes and modal damping values) and system parameters (stiffness, mass and damping matrices) are obtained. These identified parameters can then be used to characterize and monitor the service of the bridge structure in the future. Analytical models of the structure can also be validated using these parameters [1,2]. The paper presents a procedure for estimating the traffic load bearing capacity of the steel arch highway viaduct Bridge Structure 205 (DC1–9, 755 m) constructed on Highway D1 in Nord Slovakia (Fig. 1) over the natural hollow basin via dynamic tests of the viaduct structures.

Multi-station electron scrubbing and performance testing device of large-area MCP

2016 ◽  
Author(s):  
Yun-sheng Qian ◽  
LiMing Tang ◽  
ChengXin Song ◽  
Jian Liu ◽  
Cheng Feng ◽  
...  
Keyword(s):  
Performance Testing ◽  
Testing Device ◽  
Large Area ◽  
And Performance

Influence of Carbon Content on Fe-Cu Alloy Material Performance in Induction Motor with Compound Cage Rotor

2011 ◽  
Vol 117-119 ◽  
pp. 1223-1226
Author(s):  
Wei Li Li ◽  
Xiao Chen Liu ◽  
Jun Ci Cao
Keyword(s):  
Carbon Content ◽  
Induction Motor ◽  
Bridge Circuit ◽  
Testing Device ◽  
Cu Alloy ◽  
Alloy Material ◽  
New Type ◽  
And Performance ◽  
Cage Rotor ◽  
Microstructure And Performance

New type Fe-Cu alloy is used in the bar of induction motor with compound cage rotor(IMCCR). In this paper, the preparation of three kinds of Fe-Cu alloy is introduced. The influence of its microstructures, hardness and impact toughness is studied by using metalloscope and scanning electron microscope. Meanwhile, physical propertie such as resistivity, and B-H curve is tested by using magnetic testing device and bridge circuit. The influence of carbon content changing on microstructure and performance of Fe-Cu alloy is analysised, which has positive significance to the new type material using in motor.

scholarly journals Dynamic Testing of Children’s Series Completion Ability: Cognitive Flexibility as a Predictor of Performance

2016 ◽  
Vol 6 (2) ◽  
pp. 143 ◽  
Author(s):  
Femke E. Stad ◽  
Karl H. Wiedl ◽  
Wilma C. M. Resing
Keyword(s):  
Cognitive Flexibility ◽  
Test Performance ◽  
Dynamic Testing ◽  
Dynamic Test ◽  
Control Group ◽  
Control Group Design ◽  
Instructional Needs ◽  
In Series ◽  
Series Completion ◽  
And Performance

<p>Dynamic testing aims to explore a child’s potential to learn by assessing improvement after training. In this study we investigated the relationship between performance on a dynamic test of series completion and children’s cognitive flexibility. This was done using a pre-test-trainingpost-test control-group design with 95 children, aged 6-8 years (<em>M</em> = 7;1, <em>SD</em> = 12.5 months). All children were tested with a measurement of cognitive flexibility. Half of the children were trained in series completion according to a graduated prompting model, while the other half only practiced. Based on initial ability and performance change after training, children were classified as non-learner, learner or high performer. The results showed that training improved series completion performance more than practice-only. Cognitive flexibility predicted static pre-test performance and instructional needs during training and might therefore be of importance in the assessment of learning potential.</p>

Extensions of Cognitive Ability Assessment With Dynamic Testing Using Self-Regulated Learning

2013 ◽  
Vol 12 (2) ◽  
pp. 230-250 ◽  
Author(s):  
Pearly Teo ◽  
John Roodenburg
Keyword(s):  
Test Performance ◽  
Dynamic Testing ◽  
Learning Experience ◽  
Control Group ◽  
Mediated Learning ◽  
Thinking Aloud ◽  
Self Regulated Learning ◽  
Regulated Learning ◽  
Integrative Assessment ◽  
And Performance

This study investigated the extension of Cattell-Horn-Carroll (CHC)–based cognitive assessment with dynamic testing using self-regulated learning (SRL). It was based on extensive review, which called for an integrative assessment of the propensity for learning and cognition of children with learning disabilities (LDs). The objective was to examine whether a brief SRL engagement during dynamic testing could enhance self-regulatory behaviors and performance in 3 CHC areas and reveal differences in SRL processes. There were 50 children at risk for LDs assigned to 2 groups: 1 group participated in dynamic extensions of assessment with SRL (involving thinking aloud and mediated learning experience); the control group undertook the same tasks without SRL. Significant intergroup differences were found in behaviors across three CHC areas and test performance in writing but not in fluid reasoning or memory tasks. Thinking-aloud processes revealed SRL capacities not evident in static assessment. Implications of dynamic extensions of tests using SRL were discussed.

scholarly journals HELMINTOS PARÁSITOS INTESTINALES DE ALGUNOS TIBURONES (PISCES: ELASMOBRANCHII) DEL GOLFO DE MÉXICO

2020 ◽  
Vol 12 (2) ◽  
Author(s):  
Oscar Méndez ◽  
Elizabeth Valero Pacheco ◽  
Miguel Angel Dorantes González
Keyword(s):  
Carcharhinus Plumbeus ◽  
Galeocerdo Cuvier ◽  
Distribución Geográfica

Se registran los helmintos intestinales de ocho tiburones pertenecientes a cuatro especies: Carcharhinus plumbeus (Nardo, 1827) (n=1), Galeocerdo cuvier (Péron y LeSueur, 1822) (n=1), Isurus oxyrhinchus Rafinesque, 1810 (n=3) y Squatina dumeril (Lesueur, 1818) (n=3), capturados por la pesca artesanal en Chachalacas, Veracruz, en octubre-noviembre de 2014 y octubre de 2015. Cada intestino se colocó en una bolsa de plástico con formaldehído al 10% y se transportaron al laboratorio. Se determinaron 20 especies pertenecientes a seis órdenes. Se colectaron 619 individuos helmintos, de estos, 615 son cestodos de 18 especies y cuatro nematodos de una especie. Los órdenes Trypanorhyncha y Phyllobothriidea registraron el mayor número de especies con siete y cinco, respectivamente. El número de especies de helmintos por especie de tiburón varió de cuatro en S. dumeril a seis en I. oxyrhinchus. Todos los tiburones estuvieron parasitados con al menos una especie de parásito. El mínimo de helmintos parásitos registrados en un tiburón fue de uno (I. oxyrhinchus y S. dumeril), mientras que G. cuvier registró el mayor número con 253 individuos. Los cestodos Aberrapex sp. Jensen, 2001; Calyptrobothrium sp. Monticelli, 1893 y Paraorygmatobothrium sp., se registraron una sola vez en S. dumeril, I. oxyrhinchus y G. cuvier con un solo individuo, mientras que Thysanocephalum thysanocephalum (Linton, 1889) Braun, 1900 registró el mayor número con 233 individuos en G. cuvier. El cestodo Disculiceps pileatus (Linton, 1891) Joyeux y Baer, 1936 se registra por primera vez en C. plumbeus. Los hábitos alimenticios y la especificidad hospedatoria son factores importantes que influyen en la composición de especies de helmintos parásitos en estos tiburones. Con estos datos ampliamos la distribución geográfica y el registro de nuevos hospederos en México.

Fatigue Design and Performance Verification of Deepwater Risers

2003 ◽  
Author(s):  
Jaime Buitrago ◽  
Michael S. Weir ◽  
Wan C. Kan
Keyword(s):  
Fatigue Tests ◽  
Postmortem Examination ◽  
Fatigue Performance ◽  
Fatigue Design ◽  
Industry Practice ◽  
And Performance ◽  
Critical Components ◽  
Deepwater Risers ◽  
Testing Protocols ◽  
Better Than

With the advent of the development of deepwater projects, ExxonMobil developed and successfully implemented a fatigue design and verification protocol for fracture-critical components, such as risers and tendons, to ensure design performance and reliability. This protocol has now become an industry practice. This paper discusses the analytical, fabrication, and testing aspects of the design process. The linkage among actual weld performance, welding procedures and inspection reliability is addressed. From the design implementation standpoint, reliability of the fabrication inspection is the key issue. Practical methodologies were developed to conduct and interpret the fatigue tests. In particular, specimen design, instrumentation, testing protocols, and postmortem examination are discussed. Data generated by testing 56 full-scale risers of various sizes and welded by different procedures are also presented. These data, including tests past 100 million cycles, show that (1) actual riser fatigue performance can be substantially better than that recommended by codes, (2) failures can occur in the long-life regime, and (3) fatigue performance varies with riser size and thickness. However, as a matter of practice, analyses, fabrication and testing are required for particular designs.

Estimating the Thermal State and Methodological Issues in Gas Dynamic Testing of Refractory Ceramic Samples

2020 ◽  
pp. 45-65
Author(s):  
V.A. Tovstonog ◽  
V.I. Tomak ◽  
A.S. Burkov
Keyword(s):  
Real World ◽  
Gas Flow ◽  
Thermal Stresses ◽  
Dynamic Testing ◽  
Thermal State ◽  
Material Selection ◽  
Integral Methods ◽  
Wide Range ◽  
State Models ◽  
And Performance

Material selection for aerospace structural and power plant units subjected to thermal stresses is based on thorough investigation of their physical, mechanical and optical properties in a wide range of temperatures up to 2500--3000 K, which are in practice the highest possible. However, it is exceptionally difficult and expensive to obtain the whole extent of data on the properties of structural and refractive materials currently in development that is required to analytically estimate the thermal state and performance of the structures designed to be subjected to thermal stresses. Moreover, the theoretical thermal state models in use are most often based on a number of assumptions, which means that they will need to be validated against experimental investigation data. As a result, integral methods of estimating material performance under intended real-world thermal and force loads become highly important. Ground-based development testing using simulation installations will solve this problem. While testing, it is important to ensure that the simulated thermal modes of the object being tested match its real-world thermal modes. The paper considers these issues regarding estimating refractory ceramics performance subjected to a high-temperature gas flow

ASSESSING THE INFLUENCE OF MODIFICATIONS ON IN-SERVICE PERFORMANCE OF STRUCTURAL SYSTEMS USING VIBRATION MEASUREMENTS

2009 ◽  
Vol 09 (04) ◽  
pp. 729-744
Author(s):  
NICHOLAS HARITOS
Keyword(s):  
Model Updating ◽  
Dynamic Testing ◽  
Service Condition ◽  
Pile Group ◽  
Integrity Assessment ◽  
Wrought Iron ◽  
System A ◽  
Pass Through ◽  
And Performance ◽  
Floor System

This paper outlines application of dynamic testing to three separate structures where evaluations of their in-service condition and performance were required. In two of these cases, both bridges, model updating procedures enabled identification of key structural properties for performing an integrity assessment. In the case of the first bridge, dynamic testing was able to demonstrate that the first attempt at introducing bandbeams to strengthen the bridge over its piers was virtually ineffective in stiffening the bridge. However, after these bandbeams were replaced, similar dynamic testing verified that the new work was now in fact so effective in stiffening this same bridge. Dynamic testing of the second bridge, a historical wrought iron swing bridge, was able to verify the integrity of the central pile group about which this bridge swings to allow riverboats to pass through. For the third case, involving a specialist laboratory floor system, a variety of excitation options were exercised to establish the acceptability of the floor to stringent criteria on vibration response levels.

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