Search results for "lcsh:T"
showing 10 items of 2832 documents
Electronic Energy Meter Based on a Tunnel Magnetoresistive Effect (TMR) Current Sensor
2017
In the present work, the design and microfabrication of a tunneling magnetoresistance (TMR) electrical current sensor is presented. After its physical and electrical characterization, a wattmeter is developed to determine the active power delivered to a load from the AC 50/60 Hz mains line. Experimental results are shown up to 1000 W of power load. A relative uncertainty of less than 1.5% with resistive load and less than 1% with capacitive load was obtained. The described application is an example of how TMR sensing technology can play a relevant role in the management and control of electrical energy.
Patterning of supported gold monolayers via chemical lift-off lithography
2017
The supported monolayer of Au that accompanies alkanethiolate molecules removed by polymer stamps during chemical lift-off lithography is a scarcely studied hybrid material. We show that these Au–alkanethiolate layers on poly(dimethylsiloxane) (PDMS) are transparent, functional, hybrid interfaces that can be patterned over nanometer, micrometer, and millimeter length scales. Unlike other ultrathin Au films and nanoparticles, lifted-off Au–alkanethiolate thin films lack a measurable optical signature. We therefore devised fabrication, characterization, and simulation strategies by which to interrogate the nanoscale structure, chemical functionality, stoichiometry, and spectral signature of t…
IEA EBC Annex83 Positive Energy Districts
2021
At a global level, the need for energy efficiency and an increased share of renewable energy sources is evident, as is the crucial role of cities due to the rapid urbanization rate. As a consequence of this, the research work related to Positive Energy Districts (PED) has accelerated in recent years. A common shared definition, as well as technological approaches or methodological issues related to PEDs are still unclear in this development and a global scientific discussion is needed. The International Energy Agency’s Energy in Buildings and Communities Programme (IEA EBC) Annex 83 is the main platform for this international scientific debate and research. This paper describes the challeng…
Pathways for the amplification of agroecology in African sustainable urban agriculture
2020
A growing awareness that highly intensified agricultural systems have made a substantial worldwide contribution to the worsening of the resilience capacity of natural ecosystems has, over the last twenty years, brought general attention to agroecological management models. This aspect is even more evident in industrial agriculture, which is based on the use of multiple chemical products derived from non-natural synthesis. In more developed countries, a new idea of ecology linked to agricultural production has been increasingly developed and, for this reason, there has been a greater diffusion of differentiated agricultural models taking into consideration the environmental impact of product…
¿Por qué los estudiantes de la Universidad Pedagógica ISFODOSU escogen la carrera de Educación?
2020
As part of research aimed at establishing the profiles of students of new entry at ISFODOSU, we include vocational variables to determine the most important motivations for the choice of career of the participants, as well as for the election of this university and opinion on its technological resources. The sample (No. 744) was chosen at random, proportionally among the Enclosures, Careers and Sex strata. First, we validate the FIT-Choice scale with two confirmatory factorial analyses. The 12 motivational factors showed a good level of fit (RMSEA .062; CFI .92 and TLI .901, as well as the 6 perceptual factors (RMSEA .062; CFI .944 and TLI .924). The reliability of the motivational factors …
Test-retest reliability and validity of a web-based food-frequency questionnaire for adolescents aged 13-14 to be used in the Norwegian Mother and Ch…
2014
Background: The assessment of food intake is challenging and prone to errors; it is therefore important to consider the reliability and validity of the assessment methods.Objective: The aim of this study was to analyze the reproducibility and validity of a developed food-frequency questionnaire (FFQ) for use among adolescents.Design: In total, 58 students (aged 13–14) from four different schools in the southern part of Norway participated in the reproducibility study of filling out the FFQ 4 weeks apart. In addition, 93 students participated in the relative validity study where the FFQ was compared to 2×24-hour dietary recalls, while 92 students participated in the absolute validity study w…
Tensions and challenges concerning ethics on video research with young children : experiences from an international collaboration among seven countri…
2018
This article and the four videos linked to this article are a result of the earliest experiences in establishing an international research collaboration among seven countries in the Project Social and emotional experiences in transition through the early years. We draw attention to the complex issues surrounding the many processes, beliefs and attitudes about infants in research that permeated our processes of gaining ethical approval for the international study and which posed many challenges for our project. Through a process of reflective analysis, we have identified a range of ethical tensions and issues which the different countries involved in this international study faced in gaining…
Numerical Simulations of the Flow Field of a Submerged Hydraulic Jump over Triangular Macroroughnesses
2021
The submerged hydraulic jump is a sudden change from the supercritical to subcritical flow, specified by strong turbulence, air entrainment and energy loss. Despite recent studies, hydraulic jump characteristics in smooth and rough beds, the turbulence, the mean velocity and the flow patterns in the cavity region of a submerged hydraulic jump in the rough beds, especially in the case of triangular macroroughnesses, are not completely understood. The objective of this paper was to numerically investigate via the FLOW-3D model the effects of triangular macroroughnesses on the characteristics of submerged jump, including the longitudinal profile of streamlines, flow patterns in the cavity regi…
Internalization of novel non-viral vector TAT-streptavidin into human cells
2007
BMC Biotechnology, 7 (1)
Procedures for study of teaching practices. Literature Review
2012
Interest in studying teaching practices has increased, because of the need to evaluate teachers and dissatisfaction with the usual ways of doing it. Recent approaches with Value-Added Models, based on students’ results on achievement tests do not seem satisfactory. The article is based on a review of literature and classifies the approaches to practices in three groups: instruments based on information given by teachers; observation protocols; and approaches based on the analysis of products of the practices. Specific tools are described and advantages and disadvantages of the three approaches are discussed. El interés por las prácticas docentes ha aumentado, en parte por la necesidad de ev…