202 research outputs found
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The Impact of the Privatization of Telecommunications in Peru and the Welfare of Urban Consumers
Socioeconomic and technical considerations to mitigate land and water degradation in the Peruvian Andes
This project aims to increase agricultural productivity, incomes, and sustainable management of
land and water by small farmers in the rural Sierra region of Peru. Although results demonstrate
the effectiveness of increased productivity and commercialization of high value agricultural
commodities, this type of activity may be limited to certain parts of the watershed with access to
irrigation and startup capital. Interventions promoting commercialization, such as those of
CEDEPAS Norte, may result in reduced soil degradation and decreased conversion of pastures to
cropland. On the other hand, the evaluation results for PRONAMACHCS indicate how difficult it is
to improve the standard of life of the population by focusing exclusively on soil and water
conservation techniques. Thus, this analysis indicates that a combination of activities may be
necessary in order to improve productivity in the short term and promote adoption of sustainable
soil and water conservation techniques in the medium and long term
Toward the Control of the Smoldering Front in the Reaction-Trailing Mode in Oil Shale Semicoke Porous Media
Results of an experimental investigation on the feasibility of propagating a smoldering front in reaction-trailing mode throughout an oil shale semicoke porous medium are reported. For oil recovery applications, this mode is particularly interesting to avoid low-temperature oxidation reactions, which appear simultaneously with organic matter devolatilization in the reaction-leading mode and are responsible for oxidation of part of the heavy oil. The particularity of this mode is that, contrary to the reaction-leading mode largely studied in the literature, the heat-transfer layer precedes the combustion layer. This leads to two separated high-temperature zones: (i) a devolatilization zone (free of oxygen), where the organic matter is thermally decomposed to incondensable gases, heavy oil, andfixed carbon, also called coke in the literature, without any oxidation, followed by (ii) an oxidation zone, where thefixed carbon left by devolatilization is oxidized. The transition from reaction-leading to reaction-trailing mode was obtained using low oxygen contents in the fed air. It is shown that two distinct layers, the heat-transfer layer and the combustion layer, propagate in a stable and repeatable way. The decrease of the oxygen fraction leads to a decrease of the smoldering temperature and to strongly limit the decarbonation of the mineral matrix. The CO2 emissions are limited. Regardless of the front temperature, all of the fed oxygen is consumed and all of thefixed carbon is oxidized at the passage of the smoldering front
Inclusive Design of Workspaces: Mixed Methods Approach to Understanding Users
Accessible design within the built environment has often focused on mobility conditions and has recently widened to include mental health. Additionally, as one in seven are neurodivergent (including conditions such as ADHD, autism, dyslexia, and dyspraxia), this highlights a growing need for designing for ‘non-visible’ conditions in addition to mobility. Emphasised by the growing disability pay gap and the disability perception gap, people with disabilities are still facing discrimination and physical barriers within the workplace. This research aimed to identify key ways of reducing physical barriers faced by people with a disability and thus encourage more comfortable and productive use of workspaces for all. Once the need for designing for a spectrum of users and inclusive workspace design was understood, a survey was then circulated to students and staff at a large university in the UK (working remotely from home), with the aim of understanding how people have adapted their home spaces and what barriers they continue to face. Quantitative and qualitative results were compared to the literature read with key issues emerging, such as separating work and rest from spaces in bedrooms. The survey findings and literature were evaluated, extracting key performance-based goals (e.g., productivity and focus within a study space) and prescriptive design features (e.g., lighting, furniture, and thermal comfort), whilst also considering the inclusivity of these features. The key conclusion establishes that, to achieve maximum benefit, it is important to work with the users to understand specific needs and identify creative and inclusive solutions
Pyrolysis of medium-density fiberboard: optimized search for kinetics scheme and parameters via a genetic algorithm driven by Kissinger's method
The pyrolysis kinetics of charring
materials plays an important
role in understanding material combustions especially for construction
materials with complex degradation chemistry. Thermogravimetric analysis
(TGA) is frequently used to study the heterogeneous kinetics of solid
fuels; however, there is no agreed method to determine the pyrolysis
scheme and kinetic parameters for charring polymers with multiple
components and competing reaction pathways. This study develops a
new technique to estimate the possible numbers of species and sub-reactions
in pyrolysis by analyzing the second derivatives of thermogravimetry
(DDTG) curves. The pyrolysis of a medium-density fiberboard (MDF)
in nitrogen is studied in detail, and the DDTG curves are used to
locate the temperature of the peak mass-loss rate for each sub-reaction.
Then, on the basis of the TG data under multiple heating rates, Kissinger’s
method is used to quickly find the possible range of values of the
kinetic parameters (<i>A</i> and <i>E</i>). These
ranges are used to accelerate the optimization of the inverse problem
using a genetic algorithm (GA) for the kinetic and stoichiometric
parameters. The proposed method and kinetic scheme found are shown
to match the experimental data and are able to predict accurately
results at different heating rates better than Kissinger’s
method. Moreover, the search method (K–K method) is highly
efficient, faster than the regular GA search alone. Modeling results
show that, as the TG data available increase, the interdependence
among kinetic parameters becomes weak and the accuracy of the first-order
model declines. Furthermore, conducting TG experiment under multiple
heating rates is found to be crucial in obtaining good kinetic parameters
Work in Progress: Transformational Change in a Masters-level Integrated Capstone Design Course that Partners Industry and Academia
Integrated capstone design courses in civil engineering pose a major challenge for educators because of the breadth of topics covered. Partnering with industry has historically provided a way to alleviate some of these challenges and provide a more authentic design experience. While external partnership in capstone design courses can provide added authenticity as well as fringe benefits such as networking opportunities, there are risks associated with an industry-driven approach. We also argue there is a need to shift from an emphasis on product to pedagogy in capstone design and that authenticity from industry is not an end in itself. In this work-in-progress paper, we present our project to reimagine the integrated capstone design course at a large, public research university in the United Kingdom. This project has three major goals: (1) Develop an understanding of how to balance industry involvement; (2) Generate mechanisms for sustainable adoption of changes; and (3) Evaluate short- and long-term student outcomes for the course. We will present an overview of our intended curricular changes as well as research and evaluation plans to date. This project fits uniquely in the current literature on engineering design education in that it centers around a masters-level course and challenges the notion of what constitutes healthy industry partnership. As a starting point, our first research question considers how the current capstone design course came to be a primarily outsourced effort and what factors impacted this organizational shift to lower academic ownership from within the department
A Review of Sociological Issues in Fire Safety Regulation
This paper presents an overview of contemporary sociological issues in fire safety. The most obviously social aspects of fire safety—those that relate to the socioeconomic distribution of fire casualties and damage—are discussed first. The means that society uses to mitigate fire risks through regulation are treated next; focusing on the shift towards fire engineered solutions and the particular challenges this poses for the social distribution and communication of fire safety knowledge and expertise. Finally, the social construction of fire safety knowledge is discussed, raising questions about whether the confidence in the application of this knowledge by the full range of participants in the fire safety design and approvals process is always justified, given the specific assumptions involved in both the production of the knowledge and its extension to applications significantly removed from the original knowledge production; and the requisite competence that is therefore needed to apply this knowledge. The overarching objective is to argue that the fire safety professions ought to be more reflexive and informed about the nature of the knowledge and expertise that they develop and apply, and to suggest that fire safety scientists and engineers ought to actively collaborate with social scientists in research designed to study the way people interact with fire safety technology
Investigating Varied Pedagogical Approaches for Problem-Based Learning in a Fire Safety Engineering Course
Fire safety engineering is a critical component of a well-rounded engineering undergraduate curriculum but is
understudied in the context of engineering education literature. Guided by previous work in problem-based
learning, we conducted a multiple case study structured around three sections of a fire safety engineering course
for students across engineering programmes. Our goal was to develop a better understanding of the impact of
different pedagogical approaches on students. These approaches were chosen for study because they align with
predominating approaches to industry practice in fire safety engineering. Classroom observations and student
coursework from each of the three sections were used to evaluate the different approaches: (A) controlling (the
specialist approach), (B) student autonomy (the generalist approach), and (C) combination strategy
(autonomous/generalist and controlling/specialist). Findings confirm more autonomous/generalist approaches
foster positive student experiences and outcomes, but a balance of instructional techniques is still needed. It is
clear that more work needs to be done to explore engineering education in the context of fire safety engineering,
and this study provides preliminary results that suggest areas for future scholarship
The Cognitive Link Between Geography and Development: Iodine Deficiency and Schooling Attainment in Tanzania
An estimated 20 million children born each year are at risk of brain damage from in utero iodine deficiency, the only micronutrient deficiency known to have significant, non-reversible effects on cognitive development. Cognitive damage from iodine deficiency disorders (IDD) has potentially important implications for economic growth through its effect on human capital attainment. To gauge the magnitude of this influence, we evaluate the impact of reductions in fetal IDD on child schooling attainment that resulted from an intensive distribution of iodized oil capsules (IOC) in Tanzania. We look for evidence of improvements in cognitive ability attributable to the intervention by assessing whether children who benefited from IOC in utero exhibit higher rates of grade progression at ages 10 to 14 relative to siblings and older and younger children in the district who did not. Our findings suggest that reducing fetal IDD has significant benefits for child cognition: Protection from IDD in utero is associated with 0.36 years of additional schooling. Furthermore, the effect appears to be substantially larger for girls, consistent with new evidence from laboratory studies indicating greater cognitive sensitivity of the female fetus to maternal thyroid deprivation. There is no indication that IOC improved rates of illness or school absence due to illness, suggesting that IOC improves schooling through its effect on cognition rather than its effect on health. However, there is weak evidence that the program also reduced child but not fetal or infant mortality, which may bias downward the estimated effect on education. Cross-country regression estimates corroborate the results from Tanzania, indicating a strong negative influence of total goiter rate and strong positive influence of salt iodization on female school participation. Together, these findings provide micro-level evidence of the direct influence of ecological conditions on economic development and suggest a potentially important role of variation in rates of learning disability in explaining cross-country growth patterns and gender differences in schooling attainment.
Downward Flame Spread over PMMA Spheres
Experiments were conducted to measure downward flame spread over PMMA spheres, and an underpinning theoretical basis was developed to explain the relevant mechanisms governing flame spread over spherical geometries. Flame spread over a sphere was classified into two distinct regimes, that being spread over the upper and lower hemispheres. Experiments were conducted using cast PMMA spheres 40 and 50 mm in diameter. Samples were ignited at the top of the sphere and the progression of the flame front was determined using video analysis. The time resolved flame spread rate was found to increase nearly linearly in time while the flame spread across the upper hemisphere of the sample (at rates ranging from approximately 2.0–3.5 mm/min). Flame spread on the lower hemisphere was observed to accelerate nonlinearly reaching instantaneous flame spread rates greater than 15 mm/min. The flame spread rates were found to be unsteady (i.e., continuously increasing) throughout each experiment. A Stokes flow solution was found to adequately characterize the opposed flame spread rate over the upper hemisphere with respect to the induced buoyant flow. Flame spread rates in the lower hemisphere were found to be controlled by a combination of increasing velocity of the ambient flow and increased heat transfer through the interior of the solid. Flame spread rates for each diameter tested were normalized and presented as a function of the relative angle of inclination at the flame front, . Thus, the two regimes of flame spread identified in this work are largely independent across sphere size for the diameters used in this study. The study of flame spread over spheres provides a unique condition to observe the transition from spread dictated by a well-defined flow condition to one in which heat transfer effects through the solid become increasingly significant
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