42 research outputs found
Reading and writing development of low-achieving adolescents: The roles of linguistic knowledge, fluency, and metacognitive knowledge
No full textWhereas school and society pose high demands on youngsters’ reading and writing skills, many adolescents experience difficulties in understanding what they read and in expressing their thoughts in comprehensible texts. Especially low-achieving students in the lowest educational tracks in the Netherlands experience such difficulties. This dissertation addresses the roles of various types of knowledge and skills that are important to the reading comprehension and writing proficiency of these low-achieving adolescents. Three empirical studies focus on individual differences in Dutch reading comprehension and writing proficiency of 51 low-achieving adolescents, and on the extent to which these differences can be explained by individual differences in linguistic knowledge, fluency, and metacognitive knowledge. In addition, the development in reading comprehension and writing proficiency of these students from Grade 7 to 9 is analyzed, as well as contributions of linguistic knowledge, fluency, and metacognitive knowledge to this development. Since language-minority students form a large proportion of low-achieving adolescents, differences between language-minority and native students in the sample are also investigated. The results show the progress low-achieving adolescents make in reading comprehension and writing proficiency between Grade 7 and Grade 9. The findings also provide unique insights into the contributions of several components of reading and writing to this progress
Reading and writing development of low-achieving adolescents: The roles of linguistic knowledge, fluency, and metacognitive knowledge
No full textWhereas school and society pose high demands on youngsters’ reading and writing skills, many adolescents experience difficulties in understanding what they read and in expressing their thoughts in comprehensible texts. Especially low-achieving students in the lowest educational tracks in the Netherlands experience such difficulties. This dissertation addresses the roles of various types of knowledge and skills that are important to the reading comprehension and writing proficiency of these low-achieving adolescents.Three empirical studies focus on individual differences in Dutch reading comprehension and writing proficiency of 51 low-achieving adolescents, and on the extent to which these differences can be explained by individual differences in linguistic knowledge, fluency, and metacognitive knowledge. In addition, the development in reading comprehension and writing proficiency of these students from Grade 7 to 9 is analyzed, as well as contributions of linguistic knowledge, fluency, and metacognitive knowledge to this development. Since language-minority students form a large proportion of low-achieving adolescents, differences between language-minority and native students in the sample are also investigated.The results show the progress low-achieving adolescents make in reading comprehension and writing proficiency between Grade 7 and Grade 9. The findings also provide unique insights into the contributions of several components of reading and writing to this progress
Application of direct analysis to pulsating and oscillating phenomena
No full textElectrical Engineering, Mathematics and Computer Scienc
Limitations to non-isothermal flow in lubricant films due to viscous-shear heating
No full textMechanical Maritime and Materials Engineerin
Het stadsgewest: Een studie over den trek naar de steden en zijn gemeentelijk-economische gevolgen
No full textCivil Engineering and Geoscience
On the effect of turbulence on bubbles: Experiments and numerical simulations of bubbles in wall-bounded flows
No full textPrevious research has shown that the addition of gas bubbles to a turbulent boundary layer in water can reduce the local skin-friction drag by up to 80%. Application of this technique to ships seems promising, but to date no significant drag reductions are obtained on full-scale ships. More knowledge about the drag reduction mechanism is required to better understand its restrictions and potential. The dispersion of small bubbles (d+ of about 1) in horizontal turbulent channel flow is studied by numerical simulations and by experiments with simultaneous PIV and bubble shadowgraphy. It is shown that the equilibrium bubble concentration distribution is described by a Rouse-profile, based on a gradient-diffusion hypothesis. The combination of turbulent mixing and a wall-normal concentration gradient results in a preferential concentration, so despite the small Stokes number (St<<1) the bubbles are not ideal flow tracers. Bubbles are driven away from the wall by turbophoresis, which may create a bubble-free layer that reduces drag reduction effectiveness. Finally, the drag reducing effect of electrolysis bubbles is determined from measurements of the velocity profile. In the literature high local drag reductions are obtained with very low concentrations of small bubbles, but in our experiments neither local or global drag reductions are measured. Therefore, the bubble drag reduction effectiveness is limited and seems to be essentially caused by a density-reduction effect.Proces and EnergyMechanical, Maritime and Materials Engineerin
The City-Centric Dataset: Metropolitan Geographic Definitions and Code for US Metropolitan Statistical Areas (MSAs), 1980-2020
No full textComparative urban research in the USA has yet to fully grapple with geographic and definitional boundary changes of urban areas across time, resulting in spatial error and bias that severely affects empirical results. In the accompanying paper published in PLOS ONE, we center the urban area as the fundamental unit of analysis—a city-centric approach—to provide robust and dynamic metropolitan definitions that advance comparative urban studies while improving precision and accuracy in urban data analysis across different time scales.This dataset includes a new spatial dataset, programming code, and metropolitan geographic definitions for the manuscript "Advancing Methods for Comparative Urban Research: A City-Centric Protocol and Longitudinal Dataset for US Metropolitan Statistical Areas" (PLOS ONE). This dataset provides the customized Public Use Microdata Sample (PUMS) definitions used in our study that make US Metropolitan Statistical Areas (MSA) geographies comparable over time, as well as the code to process and create the results and figures in the paper. Our geographic definitions cover the 50 largest US MSAs from 1980-2020. If you use this dataset or code, please cite as follows: Jurjevich, Jason R., Katie Meehan, Nicholas M.J.W. Chun, and Greg Schrock (2025): "The City-Centric Dataset: Metropolitan Geographic Definitions and Code for US Metropolitan Statistical Areas (MSAs), 1980-2020." Tucson, AZ: University of Arizona Research Data Repository. DOI: 10.25422/azu.data.25743963 For inquiries regarding the contents of this dataset, please contact the Corresponding Author listed in the README.txt file. Administrative inquiries (e.g., removal requests, trouble downloading, etc.) can be directed to [email protected]
The relative importance of product attributes: Consumer decision theories in new-product development
No full textIndustrial Design Engineerin
Kademuur m.b.v. diepwanden: Kostenvergelijking met conventionele methoden
No full textBij de kademuren die de laatste jaren in de diepere havens van Nederland gemaakt zijn, wordt de grand gekeerd door combiwanden. Dit is voor de hier gerdende grondopbouw en belastingen de meest geschikte constructievorm, deze wordt hier als 'conventionele methode' gezien. Een alternatieve manier om de grand te keren is de diepwand. Deze techniek wordt in Nederland relatief weinig gebruikt, voor kademuren is deze in diepe havens zelfs nog nooit toegepast. In de havens van de landen om ons heen, zoals Le Havre, Antwerpen en Hamburg wordt echter wel regelmatig voor de diepwand gekozen. Bij een toenemende havendiepte moeten de kerende wanden zwaarder en langer worden, wat bij de combiwanden tot problemen bij het heien leidt. Voor diepwanden geldt dat een gratere doorsnede of diepte nauwelijks extra moeilijkheden met zich meebrengt, zodat verwacht kan worden dat bij extreme omstandigheden de diepwand goedkoper is. In dit afstudeerpraject is voor de Amazonehaven op de Maasvrakte onderzocht in hoeverre dit, voor de havendiepten die in de nabije toekomst nodig zijn, kan leiden tot constructies waarbij de diepwand het goedkopere alternatief oplevert. Verder zijn redenen aangedragen waarom in de ons omringende landen de kademuren met diepwanden wel goedkoper kunnen zijn dan met combiwanden. Om de eerste doelstelling (Kan de diepwand voor de Amazonehaven in de nabije toekomst goedkoper zijn?) te bewerkstelligen zijn allereerst de conventionele typen en grondopbouw gemodelleerd en berekend (bodemniveau NAP. -18.50 m). De gegevens die hieruit volgen (veiligheden, deformaties) dienen als leidraad voor de ontwerpen waarbij de grond door diepwanden gekeerd wordt. Voor de diepwand-varianten zijn alternatieven opgesteld, waarvan de 6 meest reele vormen zijn gedimensioneerd. Bij de berekeningen van de eerste varianten zijn analyses gemaakt van het gedrag van de wanden bij verschillende inklemmingen, wandstijfheden en ankerstijfheden. De uitkomsten hiervan zijn op de overige alternatieven toegepast zodat het ontwerpen sneller kon geschieden. Uit de analyses blijkt dat de stijfheid van de verankering weinig invloed heeft op de optredende ankerkrachten en momenten in de wand, maar dat de verhouding van de stijfheid van de wand en de ankers wel de vorm van deformeren be;·nvloedt. Aangezien de deformaties geen maatgevend criterium vormen is deze invloed van klein belang. Verder bleek dat de mate van inklemming in de grond weliswaar een grate invloed heeft op het momentverloop in de wand maar dat per situatie (optredende maximale momenten en gekozen wanddikte) de optimale verhouding tussen de te produceren hoeveelheid diepwand en benodigde wapening moet worden gezocht. Uit de begrotingen van de gedimensioneerde alternatieven blijkt dat MV-palen aanzienlijk efficienter dat ankerstaven met -schermen zijn. Tevens is dUidelijk geworden dat varianten met een ontlastkoker boven de diepwanden verreweg de goedkoopste alternatieven zijn. Na de keuze van het ontwerp is gepoogd de kosten van dit alternatief te verlagen door de wand stijf te verbinden met de koker. Door deze 'verende inklemming' wordt het moment in het veld van de wand gereduceerd, voor het beschouwde bodemniveau (NAP. -18.50 m) is dit echter niet effectief. De extra wapening door het inklemmingsmoment is meer dan de vermindering van de wapening door de reductie van het veldmoment. Het gekozen diepwand-concept wordt vervolgens ook voor diepere havens gedimensioneerd, namelijk met een bodem op NAP. -21.50 m en NAP. -24.50 m. Voor de combiwand-varianten is dit eveneens gedaan om een vergelijking mogelijk te maken. De berekeningen van de diepere havens zijn voor beide wand-typen ook uitgevoerd met een hogere ontlastkoker. De duurdere koker maakt een kortere en minder zwaar belaste wand mogelijk, waardoor in sommige gevallen de totale kosten dalen.Hydraulic EngineeringCivil Engineering and Geoscience
The acquisition of subset and superset phonotactic knowledge in a second language
No full textCan second language (L2) learners acquire a grammar that allows a subset of the structures allowed by their native grammar? This question is addressed here with respect to acquisition of phonotactics. On the assumption that the L2 initial state equals the native grammar's final state, learnability theory would predict that a lack of negative evidence for phonotactic structures that are illegal in the target language precludes acquisition of the target grammar. This prediction is tested for L1-Russian (superset) and L1-Spanish (subset) L2 learners of Dutch by means of word-likeness judgments and lexical decision experiments. Participants responded to nonwords containing consonant clusters in onsets and codas that are legal (1) only in Russian, (2) only in Russian and Dutch, or (3) in all three languages. The results converge to show that advanced L1-Russian and L1-Spanish L2 learners possess native-like phonotactic knowledge. Analysis shows that this knowledge cannot be attributed to transfer of lexical statistics from the native language. The results suggest that L2 phonotactic acquisition is not affected by subset/superset relations between the native language and target language. Some possible explanations for our findings are discussed
