150 research outputs found
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Role of Low Carbon Energy Technologies in Near Term Energy Policy
In the first part of this thesis, we use a multi-model framework to examine a set of possible future energy scenarios resulting from R&D portfolios of Solar, Nuclear, Carbon Capture and Storage (CCS), Bio-Fuels, Bio-Electricity and Batteries for electric transportation. We show that CCS significantly complements Bio-Electricity, while most of the other energy technology pairs are substitutes. From the probabilistic analysis of future energy scenarios we observe that portfolios with CCS tend to stochastically dominate those without CCS; portfolios with only renewables tend to be stochastically dominated by others; and that there are clear decreasing marginal returns to scale. We also find that, with higher damage risk, there is more incentive for technical advancement in CCS and less incentive for development of Solar energy technology.
In the second part of this thesis, we examine the optimal R&D portfolio changes at the different R&D budget levels and how risk in climate damages affects the optimal R&D portfolio. We find that the optimal portfolio is generally not robust to risk, and the optimal investments in the energy technologies vary with risk in climate damages; however R&D investments in certain energy technologies, such as Nuclear, are robust under the different risk cases. We note that while CCS plays a significant role in the optimal portfolio when there is no risk in climate damages, it plays an even more significant role in the higher climate damage risk cases. We also find that R&D investment in the Biofuels energy technology increases significantly with increase in climate damage risk, while Solar, Batteries for Electric Transportation and Bio-Electricity technologies go out of favor with increases in climate damage risk. We also propose a methodology for obtaining solutions to subset portfolio problems, based on the characteristics of the individual technologies. We prove that the subset portfolio problem is optimal if the individual technology does not interact with any of the other technologies, we confirm this in our empirical portfolio problem.
In the third part of this thesis, we conduct an illustrative global sensitivity analysis on a large scale integrated assessment model with a view to determining the primary drivers of uncertainty in the model and examining the effect of structural uncertainty on the model. We compare our results to a previous paper which conducted a one factor at a time sensitivity analysis and find that both sensitivity methods provide the same result which is different from findings from the previous paper. We find that model interactions are present even in our very limited illustrative analysis. We also conduct most of the steps needed for a full global sensitivity analysis of the model and highlight the challenges in conducting this analysis on the GCAM model. We show that there exist a need for global sensitivity analysis for accurate determination of the principal drivers of uncertainty in integrated models
Development of a Rocket Stove Using Woodash as Insulator
Abstract A rocket stove which serves as a cheaper and more safer alternative to conventional method of cooking, employing the use of solid fuels has been developed. The construction was done with our locally available metallic materials for the body and combustion chamber of the stove, using teak (khaya grandifoliala) wood ash as an insulator. An analysis of the thermal and mechanical properties of the insulating wall, fuel magazine, combustion chamber, and chimney were also performed; the law of energy conservation was used to determine the stove thermal efficiency which is 37.3%, while the Newtonâs law of cooling was used to determine the convection heat transferred by the stove body (150864 J/kg) and Stefan-Boltzmann law was used to determine the amount of heat radiated by the stove body (49.2 J/kg), thus, signifying its suitability for home heating. A less expensive but very effective materials mixture containing galvanized steel and wood ash were found to have thermal properties comparable to that of fired vermiculite and stainless steel materials which are more expensive in other improved stove designs
Design and Fabrication of an Automated Low-Cost Non-Contact Temperature Scanner and Sanitizer for Covid-19 Prevention
The rate at which the novel virus Covid-19 spread across the world in an alarming rate with high rate of death of the infected persons is quite disturbing, hence the need to checkmate its spread by quickly identifying persons with the symptoms of this viral infection. This paper discusses the development of an automated low-cost non-contact temperature scanner and sanitizer. The system automatically detects a human being, scans for temperature, and sanitizes the person with no interference required. The circuit for the system comprises an Arduino microcontroller, LCD display, relays, ultrasonic sensors, temperature sensor, 12v DC pump motion sensor and a high pressure 12v DC pump. The temperature sensor (MLX90614) senses the temperature, certifies that the value is within the specified range as controlled by its ultrasonic sensor and displays the temperature on the LCD. Thereafter, an ultrasonic sensor activates the 12V DC pump to dispense the sanitizer. At the disinfectant chamber, the motion sensor will trigger the high-pressured DC pump when it senses movement, it dispenses the body sanitizer through the nozzles. C++ was used to program the Arduino in Arduino user interface. The entire process takes 60seconds and it helps to maintain personal preventive measures as well as detecting a possible symptomatic person as fever with high temperature which is one of the major symptoms of Covid-19. The device has been tested and works effectively, and it will be very useful for any organization with one or more buildings. It can be positioned at the entrance of buildings to sanitize and scan all staff and visitors against Covid-19
Modeling and Simulation of Hydrogen Storage Device for Fuel Cell Plant
The article reviews a brief literature on the modeling of hydrogen storage device for fuel cell. Different dimensional
approaches in modeling hydrogen absorption/desorption in a metal hydride reactor for use in fuel cell are summarized. Mathematical
modeling equations involved are also stated. The effect of various operating parameters such as temperature, concentration, viscosity,
thermal conductivity and time on the gas is also verified. The importance of various simulation software with reference to their major
functions is also identified. The review concludes on the opportunities and challenges with the use of hydrogen as an alternative
renewable energ
Comparative Study of Neuronal Degenerative Potentials of Ethanolic Root Bark and Leaf Extracts of Rauwolfia Vomitoria on the Cerebellum of Adult Wistar Rats
Rauwolfia vomitoria has been used for centuries in India and Africa for treatment of a variety of disorders including snake bites and sting, insomnia and insanity. Neuronal degenerative potentials of ethanolic root bark and leaf extracts of Rauwolfia vomitoria on the cerebellum of adult wistar rats was investigated. Thirty wistar rats weighing between 170-240g were divided into six groups, each consisting of five rats. Groups A served as the normal control that received distilled water while group B served as the olive oil control that received 0.5mls of olive oil. Experimental groups C and D received 200mg/kg, 300mg/kg of ethanolic root bark extracts while groups E and F received 200mg/kg, 300mg/kg of the leaf extract orally respectively for seven days. In this study, the treatment groups showed a dose-dependent degree of silver impregnation of the cell bodies and axons. The sections of the cerebellar cortex of the treated group C, D, E and F showed various degrees of neurodegenerative changes highlighted by the silver stain impregnation which was more intense in groups C and D that received 200mg/kg and 300mg/kg ethanolic root-bark than in the groups E and F that received 200mg/kg and 300mg/kg of ethanolic leaf extract. These changes may result in cerebellar dysfunction Keywords: Ethanolic extracts, Root-bark extract, Leaf extract, Rauwolfia vomitoria
Total Reconstruction of the Upper Lip Using Bilateral Nasolabial Flaps, Submental Flap, and Mucosa Graft following Complete Resection for Squamous Cell Carcinoma
Lip reconstruction following resection for tumour or following extensive trauma may pose a challenge. This is more so when the resection is total and a complete lip has to be constructed. We present a case of lip reconstruction following a total resection of the upper lip. The procedure used in this case was a combination of bilateral nasolabial flaps with a submental flap and buccal mucosal graft lining. We believe that this provides an alternative method of total upper lip reconstruction with minimal disruption of the facial aesthesis
Multidisciplinary approach to genomics research in Africa: the AfriCRAN model
This article is an outcome of the African Craniofacial Anomalies Research Network (AfriCRAN) Human Hereditary and Health (H3A) grant planning meeting in 2012 in Lagos, Nigeria. It describes the strengths of a multidisciplinary team approach to solving complex genetic traits in the craniofacial region. It also highlights the different components and argues for the composition of similar teams to fast track the discovery of disease genes, diagnostic tools, improved clinical treatment and ultimately prevention of diseases
Key features of mcr-1-bearing plasmids from Escherichia coli isolated from humans and food
Human bite injuries in the oro-facial region at the Muhimbili National Hospital, Tanzania
<p>Abstract</p> <p>Background</p> <p>Human bites in the maxillofacial region compromise function and aesthetics, resulting in social and psychological effects. There is paucity of information regarding human bite injuries in Tanzania. The aim of the study was to assess the occurrence, treatment modalities and prognosis of human bite injuries in the oro-facial region at the Muhimbili National Hospital Dar es Salaam, Tanzania.</p> <p>Methods</p> <p>In a prospective study the details of patients with human bite injuries in the oro-facial region who attended at the Department of Oral and Maxillofacial Surgery of the Muhimbili National Hospital between January 2001 and December 2005 were recorded. Data included information on age, sex, site, duration of the injury at the time of reporting to hospital, reasons, details of treatment offered and outcome after treatment.</p> <p>Results</p> <p>A total of 33 patients, 13 males and 20 females aged between 12 and 49 years with human bite injuries in the oro-facial region were treated. Thirty patients presented with clean uninfected wounds while 3 had infected wounds. The most (45.5%) frequently affected site was the lower lip. Treatment offered included thorough surgical cleansing with adequate surgical debridement and primary suturing. Tetanus prophylaxis and a course of broad-spectrum antibiotics were given to all the patients. In 90% of the 30 patients who were treated by suturing, the healing was uneventful with only 10% experiencing wound infection or necrosis. Three patients who presented with wounds that had signs of infection were treated by surgical cleansing with debridement, antibiotics and daily dressing followed by delayed primary suturing.</p> <p>Conclusion</p> <p>Most of the human bite injuries in the oro-facial region were due to social conflicts. Although generally considered to be dirty or contaminated they could be successfully treated by surgical cleansing and primary suture with a favourable outcome. Management of such injuries often need multidisciplinary approach.</p
Association studies and direct DNA sequencing implicate some known genetic susceptibility loci in the etiology of nonsyndromic orofacial clefts in sub-Saharan African populations
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