1,138 research outputs found

    The hydrology of a small fish pond at the University of Agriculture, Makurdi Experimental Fish Farm

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    The monthly and seasonal water requirements of a small fish pond (0.068ha; maximum capacity of 613.83m super(3)) at the University of Agriculture, Makurdi Fish Farm (Benue, Nigeria) were determined during the period of February to August 1996. The sources of water for the pond were rainfall, (103.4cm), run-off (6.3cm) and regulated inflow (95.0cm). The water loss for the period were Evapotranspiration, (106.74cm), Seepage (71.64cm) and regulated discharge (25.00cm). Evapotranspiration was identified as the main source of water loss while rainfall was the major source of water gain. The mean monthly water deficit was 24.56~c11.43cm while the mean monthly surplus was 9.84~c8.05cm. The quantity of water required to maintain the optimal water level in the pond was 474.00m super(3). Preliminary water budget of the study area showed that rainfed aquaculture can be effectively carried out at Makurdi during the months of June to October with supplementary inflows during the dry season month

    Modular Supply Network Optimization of Renewable Ammonia and Methanol Co-production

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    To reduce the use of fossil fuels and other carbonaceous fuels, renewable energy sources such as solar, wind, geothermal energy have been suggested to be promising alternative energy that guarantee sustainable and clean environment. However, the availability of renewable energy has been limited due to its dependence on weather and geographical location. This challenge is intended to be solved by the utilization of the renewable energy in the production of chemical energy carriers. Hydrogen has been proposed as a potential renewable energy carrier, however, its chemical instability and high liquefaction energy makes researchers seek for other alternative energy carriers. Ammonia and methanol can serve as promising alternative energy carriers due to their chemical stability at room temperature, low liquefaction energy, high energy value. The co-production of these high energy dense energy carriers offers economic and environmental advantages since their synthesis involve the direct utilization of CO2 and common unit operations. This problem report aims to review the optimization of the co-production of methanol and ammonia from renewable energy. Form this review, research challenges and opportunities are identified in the following areas: (i) optimization of methanol and ammonia co-production under renewable and demand uncertainty, (ii) impacts of the modular exponent on the feasibility of co-production of ammonia and methanol, and (iii) development of modern computational tools for systems-based analysis

    Travelling Theory The Feminism and Womanism of Tess Onwueme

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    Osonye Tess Onwueme is arguably the leading female Nigerian dramatist today within and outside the country. Since leaving Nigeria for the United States, she seems to have acquired a deeper orientation of the concept and theory of feminism, especially feminism as praxis. The totality of her plays since A Hen too Soon explains clearly the place of time, location (ofculture), and the artistic growth that every good writer experiences. In discussing this topic, the paper shall look at three areas of Onwueme’s artistic development and shifts. Out of her over twenty plays, only four shall be used as paradigms of these three crucial phases. The first phase shall deal with her early feminism (The Broken Calabash and TheReign of Wazobia); the second phase with womanism referred to here as her early African womanism (Tell it to Women) and the third is her later and purer African womanism (Then She Said It); all discussed within the framework of the playwright’s artistic development vis-à-vis the influence of her sojourn in the United States. The paper shall also endeavour to reconcile these three phases within the framework of the feminist dilemmain Africa

    What is Globalization to Post-colonialism? An Apologia for African Literature

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    Globalization is easily understood as part of the continuing history of imperialism, indeed, of capitalist development and expansion. Have the imperial structures really been dismantled, even though the empire, free as they politically seem after independence, still writes back to the (imperial) center? This paper probes into the angelic posture that globalization seems to assume in its tackling of these complexities of identities. In this age of the clamor for national literatures and criticism, which is a fundamental principle of postcolonial literatures, will globalization automatically erode the idea of a postcolonial world and literatures? Is post-colonialism in its present phase and posture able to cater for the heterogeneous national literatures that it seeks to foreground or canonize? These constitute the frontline unease that this paper sets out to unravel; hence, the need to redefine the whole concept of globalization

    Decentralized Model for a Two-Stage Supply Chain with Exogenous Demand

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    This paper presents a formal mathematical model for managing problems of stochastic demands; confronting many industries in the society today. We consider a two- stage supply chain where the upstream manufacturer (stage2) must always fill exogenous demands from the downstream manufacturer (stage1) using  two types of expediting : Overtime production and outsourcing.Key words: Supply chain management(SCM), Supply chain(SC), Inventory, backorder, Opti-mality

    Field Effect Transistor Based on KTaO3 Perovskite

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    An n-channel accumulation-type field effect transistor (FET) has been fabricated utilizing a KTaO3 single crystal as an active element and a sputtered amorphous Al2O3 film as a gate insulator. The device demonstrated an ON/OFF ratio of 10^4 and a field effect mobility of 0.4cm^2/Vs at room temperature, both of which are much better than those of the SrTiO3 FETs reported previously. The field effect mobility was almost temperature independent down to 200K. Our results indicate that the Al2O3 / KTaO3 interface is worthy of further investigations as an alternative system of future oxide electronics.Comment: 3 pages, 3 Postscript figures, submitted to Appl.Phys.Let

    Small bowel stricture as a late sequela of superior mesenteric vein thrombosis

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    AbstractIntroductionThe increasing frequency of use of CT in patients with acute abdomen is likely to improve the diagnosis of rarely occurring conditions/causes such as superior mesenteric vein thrombosis (MVT). Despite its severe consequences, MVT often presents with nonspecific clinical features.Presentation of caseAD, a 64-year-old man was an emergency admission with vague abdominal discomfort of two weeks duration, acute upper abdominal pain, loose stools, fresh rectal bleeding and vomiting. A contrast enhanced abdominal CT showed thrombosis of the proximal portal vein and the entire length of the superior mesenteric vein (SMV) with small bowel ischaemia extending from the terminal ileum to the mid jejunal loops. Tests for paroxysmal nocturnal haemoglobinuria and Janus kinase 2 mutation yielded negative results. AD was readmitted seven months later with small bowel obstruction requiring segmental small bowel resection with end-to-end anastomosis. Abdominal CT had shown complete resolution of MVT but a small bowel stricture.DiscussionThrombosis limited to mesenteric veins results in earlier and more frequent development of infarction compared to portal combined with mesenteric venous thrombosis. Most patients may be successfully treated with anti-coagulation therapy alone. However, surgery may be required to deal with intestinal infarction or late sequela of MVT.ConclusionThis case demonstrates that MVT can be reversed by effective anticoagulation. However, the price paid for a mild to moderate effect on the bowel may be significant stricture later on. Patients escaping early bowel resection due to massive MVT leading to bowel infarction may still require resection later due to stricture

    Field-Effect Transistor on SrTiO3 with sputtered Al2O3 Gate Insulator

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    A field-effect transistor that employs a perovskite-type SrTiO3 single crystal as the semiconducting channel is revealed to function as n-type accumulation-mode device with characteristics similar to that of organic FET's. The device was fabricated at room temperature by sputter-deposition of amorphous Al2O3 films as a gate insulator on the SrTiO3 substrate. The field-effect(FE) mobility is 0.1cm2/Vs and on-off ratio exceeds 100 at room temperature. The temperature dependence of the FE mobility down to 2K shows a thermal-activation-type behavior with an activation energy of 0.6eV

    Phytochemical Screening and Identification of Bioactive Constituents of the Chloroform Extract of Icacina trichantha Tuber Peel Oliv

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    This study was carried out to identify the bioactive constituents of the tuber peels of Icacina trichanthalinna of the Icacinales family. This plant is basically selected due to its widespread use in herbal treatment. Nine compounds were identified in the chloroform extract of the tuber peel. Undecane (43.254%),2-hexanone (23.299%), Dodecanoic acid ethyl ester (6.244%) and 9-octadecynoic acid (5.915%) appeared to be the most prevailing compounds and they are known to possess antibacterial, antiviral, antioxidant, antimycobacterial, hypercholesterolemic activities. Also identified was triarachine which has been reported to have some biological activity
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