Technological and economic evaluation of conversion of potential flare gas to electricity in Nigeria

28th International Conference on Flexible Automation and Intelligent Manufacturing (FAIM2018), June 11-14, 2018, Columbus, OH, USAGlobally, over 100 billion cubic metres (BCM) of gas is flared annually and linked to an annual emission of 400 million tons of carbon dioxide. In Nigeria the annual gas production is valued at 33.21 BCM, out of which more than 50% of this volume is wasted through flaring, thereby emitting about 35 million tons of carbon dioxide. About 14.94 BCM of gas produced in Nigeria is used for a variety of activities including electricity generation. Despite this scenario, Nigeria is still unable to generate and distribute enough electricity for the citizenry. This paper therefore proposes the option to divert gas which is normally flared to generate electricity in Nigeria while minimising the associated environmental impacts. The research methodology was based on interviewing top level managers in an electricity generation company, and gas Production Company, as well as the researchers’ site observations within the two case companies. Results from this study showed that electricity generation could be improved from its current daily production rate of 4358 MW to about 12000 MW. This improvement comes from the use of 18.27 BCM of gas currently flared annually in Nigeria, which could potentially be diverted as fuel for 50 units of gas turbine with power output of 150 MW each, with an increase in daily electricity generation of 7500 MW. The study also incorporates an economic analysis for the option to generate electricity as aforementioned

Anatomical variations of the frontal sinus: A computed tomography-based study [version 2; peer review: 2 approved]

Background: The pneumatization of the frontal sinus is variable between individuals, including monozygotic twins. The volumetric anatomic variants of the frontal sinus are classified into aplasia, hypoplasia, medium-sized, and hyperplasia. We aimed to study the frontal sinus morphology in Omani patients using computed tomography (CT) evaluations. Methods: Retrospectively, 1220 frontal sinus CT scans from 610 patients investigated at Sultan Qaboos University Hospital, Oman, from January 2019 to December 2020 were reviewed. The frontal sinus morphology was classified according to the classification proposed by Guerram et al. The Chi-square test was used to determine the influence of sex. Results: With regard to the unilateral occurrence, the most prevalent frontal sinus category observed was medium-sized (13.3%), followed by hyperplasia (7.9%), hypoplasia (5.4%), and aplasia (2%) categories. Similarly, in bilateral occurrence, the most common frontal sinus category observed was medium-sized (53%), followed by hyperplasia (13.1%), hypoplasia (3.4%) and aplasia (2%) categories. Right and left frontal sinus aplasia were observed in 2.1% and 1.8% of cases, respectively. In terms of sex influence, the left unilateral (p<0.01) and the bilateral hypoplasia (p<0.05) were significantly higher in females. On the other hand, the left unilateral (p<0.01) and the bilateral hyperplasia (p<0.05) were higher in males. Conclusions: The baseline data of frontal sinus category frequencies reported in the present study is helpful in the diagnostic evaluation of sinusitis in the clinical setting. The preoperative recognition of frontal sinus types, particularly frontal sinus aplasia in multiplanar CT scans, is crucial to avoid unexpected complications while performing endoscopic sinus surgery

An overview of using small punch testing for mechanical characterization of MCrAlY bond coats

Considerable work has been carried out on overlay bond coats in the past several decades because of its excellent oxidation resistance and good adhesion between the top coat and superalloy substrate in the thermal barrier coating systems. Previous studies mainly focus on oxidation and diffusion behavior of these coatings. However, the mechanical behavior and the dominant fracture and deformation mechanisms of the overlay bond coats at different temperatures are still under investigation. Direct comparison between individual studies has not yet been achieved due to the fragmentary data on deposition processes, microstructure and, more apparently, the difficulty in accurately measuring the mechanical properties of thin coatings. One of the miniaturized specimen testing methods, small punch testing, appears to have the potential to provide such mechanical property measurements for thin coatings. The purpose of this paper is to give an overview of using small punch testing to evaluate material properties and to summarize the available mechanical properties that include the ductile-to-brittle transition and creep of MCrAlY bond coat alloys, in an attempt to understand the mechanical behavior of MCrAlY coatings over a broad temperature range