scholarly journals Empirical Analysis of the Impact Strength of Textile Knitted Barrier Meshes

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zbigniew Mikołajczyk ◽  
Beata Szałek ◽  
Katarzyna Pieklak
Keyword(s):  
Measurement Data ◽  
Test Stand ◽  
Dynamic Loads ◽  
Measuring System ◽  
Electronic Measuring ◽  
Computer Data ◽  
Analysis System ◽  
Data Analysis System ◽  
Dynamic Stress Distribution ◽  
The Impact

AbstractThe assumptions of instrumental methodology for measuring dynamic loads of knitted barrier meshes were defined. A test stand was built, original in terms of both mechanical construction and electronic measuring system, connected to a computer data analysis system. Maximum values of dynamic forces in the mesh fastening strings were determined. The correctness of the strain gauges construction and measurement data transmission systems was confirmed. Tests of multidirectional resistance to dynamic loads in the mesh fastening strings were carried out. The experiment involved dropping a ball with a mass of 5 kg and a diameter of 10 cm, from a height of 1 m and 2 m onto the mesh surface. The potential impact energy equaled Ep1 = 49.05 J and Ep2 = 98.1 J. The tests showed that the highest force values were observed for meshes with square-shaped a-jour structure, and for mesh with diamond-shaped a-jour geometry the force values were lower. A symmetrical forces distribution was observed in all the strings. The highest forces were recorded in the middle strings and the lowest in the outer ones. The conducted tests confirmed the correctness of the adopted constructional solutions of test stand for identification of dynamic stress distribution in mesh fastening strings. The developed method is a useful verification tool for numerical analysis of mechanical properties of barrier meshes.

scholarly journals Exploring the Impact of Outdoor Environmental Activities on Children Using a Qualitative Text Data Analysis System

2003 ◽  
Vol 13 (4) ◽  
pp. 684-688 ◽  
Author(s):  
T.M. Waliczek ◽  
P. Logan ◽  
J.M. Zajicek
Keyword(s):  
Data Analysis ◽  
Bloom's Taxonomy ◽  
Computer Assisted ◽  
Outdoor Classroom ◽  
Data Indexing ◽  
Bloom’S Taxonomy ◽  
Math And Science ◽  
Analysis System ◽  
Data Analysis System ◽  
The Impact

The main objective of this study was to investigate the impact of an outdoor environmental program, Math and Science in the Outdoor Classroom, on elementary grade students' creative and critical thinking, and attitudes toward math and science. Math and Science in the Outdoor Classroom is an on-campus nature program in Santa Fe, N.M. Students participated in half-day programs focusing on topics such as water, insects, soil, and weather. Twenty-one teachers from five schools volunteered 175 second through sixth graders to participate in the program and research study. Surveys were administered to students, teachers, and volunteers after completion of the program. Interview data was analyzed using QSR NUD*IST (Nonnumerical Unstructured Data Indexing Searching and Theory-building) computer-assisted qualitative data analysis system to examine respondents' perceptions of the program using Bloom's taxonomy as a theoretical framework. Results indicated that students not only learned math and science at the lower levels of Bloom's taxonomy, but were also thinking at the higher levels of synthesis and evaluation within the framework.

scholarly journals Performance evaluation of ocean color satellite models for deriving accurate chlorophyll estimates in the Gulf of Saint Lawrence

2014 ◽  
Vol 11 (6) ◽  
pp. 9299-9340
Author(s):  
M. Montes-Hugo ◽  
H. Bouakba ◽  
R. Arnone
Keyword(s):  
Chlorophyll Concentration ◽  
Ocean Color ◽  
Atmospheric Correction ◽  
Relative Bias ◽  
Wide Field ◽  
Absolute Bias ◽  
Analysis System ◽  
Data Analysis System ◽  
The Impact

Abstract. The understanding of phytoplankton dynamics in the Gulf of the Saint Lawrence (GSL) is critical for managing major fisheries off the Canadian East coast. In this study, the accuracy of two atmospheric correction techniques (NASA standard algorithm, SA, and Kuchinke's spectral optimization, KU) and three ocean color inversion models (Carder's empirical for SeaWiFS (Sea-viewing Wide Field-of-View Sensor), EC, Lee's quasi-analytical, QAA, and Garver- Siegel-Maritorena semi-empirical, GSM) for estimating the phytoplankton absorption coefficient at 443 nm (aph(443)) and the chlorophyll concentration (chl) in the GSL is examined. Each model was validated based on SeaWiFS images and shipboard measurements obtained during May of 2000 and April 2001. In general, aph(443) estimates derived from coupling KU and QAA models presented the smallest differences with respect to in situ determinations as measured by High Pressure liquid Chromatography measurements (median absolute bias per cruise up to 0.005, RMSE up to 0.013). A change on the inversion approach used for estimating aph(443) values produced up to 43.4% increase on prediction error as inferred from the median relative bias per cruise. Likewise, the impact of applying different atmospheric correction schemes was secondary and represented an additive error of up to 24.3%. By using SeaDAS (SeaWiFS Data Analysis System) default values for the optical cross section of phytoplankton (i.e., aph(443) = aph(443)/chl = 0.056 m2mg−1), the median relative bias of our chl estimates as derived from the most accurate spaceborne aph(443) retrievals and with respect to in situ determinations increased up to 29%.

Developmental Measurement of Mental Attention

1994 ◽  
Vol 17 (1) ◽  
pp. 161-200 ◽  
Author(s):  
Juan Pascual-Leone ◽  
Raymond Baillargeon
Keyword(s):  
Latent Class ◽  
Latent Class Models ◽  
Categorical Data Analysis ◽  
Test Items ◽  
Mental Demand ◽  
Mental Attention ◽  
Constructivist Model ◽  
Discrete Manner ◽  
Analysis System ◽  
Data Analysis System

A dialectical constructivist model of mental attention ("effort") and of working memory is briefly presented, and used to explicate subjects' processing in misleading test items. We illustrate with task analyses of the Figural Intersections Test (FIT). We semantically derive a set of 10 Theoretical Structural Predictions (TSP) that stipulate relations between mental attentional resources (mental-power: Mp) and the systematically varied mental demand of items (mental-demand: Md), as they jointly codetermine probable performance (conditional probabilities of passing and failing). These predictions are evaluated on first approximation using a known family of ordered Latent Class models, all probabilistic versions of Guttman's unidimensional scale. Parameters of these models were estimated using the Categorical Data Analysis System of Eliason (1990). Main results are: (1) Data fit Lazarsfeld's latent-distance model, providing initial support for our 10 predictions; (2) The M-power of children (latent Mp-classes) when assessed behaviourally may increase with age in a discrete manner, and have the potential to generate interval scales of measurement; (3) In the light of our results what statisticians often consider "error of measurement" appears (in part) to be signal, not noise: The organismic signal of misleading (Y-) processes that in their dialectical (trade-off) interaction with success-producing (X-) processes generate performance.

scholarly journals Quantification of Non-Exhaust Particulate Matter Traffic Emissions and the Impact of COVID-19 Lockdown at London Marylebone Road

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 190
Author(s):  
William Hicks ◽  
Sean Beevers ◽  
Anja H. Tremper ◽  
Gregor Stewart ◽  
Max Priestman ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Measurement Data ◽  
Emission Factors ◽  
Meteorological Conditions ◽  
Traffic Emissions ◽  
Atmospheric Particulate Matter ◽  
Exhaust Emission ◽  
Brake Wear ◽  
The Impact ◽  
Exhaust Particulate

This research quantifies current sources of non-exhaust particulate matter traffic emissions in London using simultaneous, highly time-resolved, atmospheric particulate matter mass and chemical composition measurements. The measurement campaign ran at Marylebone Road (roadside) and Honor Oak Park (background) urban monitoring sites over a 12-month period between 1 September 2019 and 31 August 2020. The measurement data were used to determine the traffic increment (roadside–background) and covered a range of meteorological conditions, seasons, and driving styles, as well as the influence of the COVID-19 “lockdown” on non-exhaust concentrations. Non-exhaust particulate matter (PM)10 concentrations were calculated using chemical tracer scaling factors for brake wear (barium), tyre wear (zinc), and resuspension (silicon) and as average vehicle fleet non-exhaust emission factors, using a CO2 “dilution approach”. The effect of lockdown, which saw a 32% reduction in traffic volume and a 15% increase in average speed on Marylebone Road, resulted in lower PM10 and PM2.5 traffic increments and brake wear concentrations but similar tyre and resuspension concentrations, confirming that factors that determine non-exhaust emissions are complex. Brake wear was found to be the highest average non-exhaust emission source. In addition, results indicate that non-exhaust emission factors were dependent upon speed and road surface wetness conditions. Further statistical analysis incorporating a wider variability in vehicle mix, speeds, and meteorological conditions, as well as advanced source apportionment of the PM measurement data, were undertaken to enhance our understanding of these important vehicle sources.

Research on Modeling Method of Runway Frictional Coefficient Measuring Vehicle Based on Impedance Diagrams

2011 ◽  
Vol 214 ◽  
pp. 133-137 ◽  
Author(s):  
Xu Dong Shi ◽  
Shou Wen Shi ◽  
Lu Zhang ◽  
Jian Li Li
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Measurement Data ◽  
Frictional Coefficient ◽  
Modeling Method ◽  
Measuring System ◽  
Discrete Fourier Transformation ◽  
Measuring Error ◽  
Impedance Diagram ◽  
Airport Runway

Airport runway friction coefficient is an important parameter to evaluate the quality of runway which is usually measured by runway friction coefficient measuring vehicle. In order to reduce the airport runway friction coefficient measuring error which comes from runway vibration caused by road roughness and vehicle its own structural characteristics, an impedance diagram is used to model the suspending system and measuring system of the measuring vehicle. The power spectral density of pavement and inverse discrete Fourier transformation are introduced to model runway surface roughness as excitation input. The rationality of the stimulating established model is validated by comparing with an airport runway surface roughness measurement data. Runway friction coefficient measuring vehicle′s measuring error can be reduced and the measurement accuracy can be improved by using the impedance diagram modeling method.

The Specific Characteristics of Shock and Blast Impacts on Construction Sites

2021 ◽  
pp. 81-88
Author(s):  
A.A. Komarov ◽  
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Dynamic Loads ◽  
Potential Hazard ◽  
Construction Sites ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Plane Crash ◽  
Nuclear Plants ◽  
The Impact

The practices of hazardous and unique facilities’ construction imply that specific attention is paid to the issues of safety. Threats associated with crash impacts caused by moving cars or planes are considered. To ensure safety of these construction sites it is required to know the potential dynamic loads and their destructive capacity. This article considers the methodology of reducing dynamic loads associated with impacts caused by moving collapsing solids and blast loads to equivalent static loads. It is demonstrated that practically used methods of reduction of dynamic loads to static loads are based in schematization only of the positive phase of a dynamic load in a triangle forms are not always correct and true. The historical roots of this approach which is not correct nowadays are shown; such approach considered a detonation explosion as a source of dynamic load, including TNT and even a nuclear weapon. Application of the existing practices of reduction of dynamic load to static load for accidental explosions in the atmosphere that occur in deflagration mode with a significant vacuumization phase may cause crucial distortion of predicted loads for the construction sites. This circumstance may become a matter of specific importance at calculations of potential hazard of impacts and explosions in unique units — for instance, in the nuclear plants. The article considers a situation with a plane crash, the building structure load parameters generated at the impact caused by a plane impact and the following deflagration explosion of fuel vapors are determined.

Sign in / Sign up

Export Citation Format

Share Document