Design and Construction of Parabolic Solar Heater Using Polymer Matrix Composite

A parabolic dish is a type of concentrating reflective device that uses the shape of a circular paraboloid to collect or project energy such as light, sound, or radio waves. The parabolic reflector transforms an incoming plane wave traveling along the axis into a spherical wave converging toward the focus. In this work concentrating dish was moulded from polyester resin reinforced with fiber glass mat and inner surface lined with Aluminum foil to increase the reflectivity. The design was made up of a moulded dish of 246cm diameter with a height of 58.2cm which has a concentration factor of 54.9. The collector was mounted on a site with latitude 6 40 22.19 and longitude 3 09 47.12 and water at 270C was heated to a temperature of 850C within 20 minutes

Ownership and co-management: towards the integrated management of Lake Victoria

The management of Lake Victoria is a high priority to the riparian countries that benefit directly from its resources. Management regulations have been formulated and implemented with the aim of maintaining the lake's ecological quality as well as sustaining fisheries exploitation for economic gain. Results indicate, however, that the regulations have not been successful in maintaining the state of the lake's ecosystem nor the fisheries. There has been a continuing decline in fish catches as well as declining biodiversity. Currently, the riparian countries are considering the introduction of a co-management regime as an alternative managerial strategy to address the lake's problems. In this paper it is argued that the failure of the former management regulations was because ownership of the lake was not clearly defined. It is further argued that even if co-management were to be successfully instituted, it will yield very minimal results if the problem of ownership is not properly addressed. This paper explores the ownership status of the lake based on data collected in Tanzania, and examines the relationship between, and significance of, ownership and co-management. The research makes recommendations for how these concepts can contribute to an integrated management of the lak

Chromosomal and histological evidences of infertility in F2 and F2 backcross. Hybrid generations of Clarias anguillaris and Heterobranchus longifilis

Male meiosis was studied in 9 different mating combinations in parental, first, second and backcross generation hybrids of Clarias anguillaris and Heterobranchus longifilis. 27 bivalents were recorded in metaphase I for seven mating combinations. The number of bivalents in F1 hybrid male x C. anguillaris female could not be determined due to a high degree of clumping of the chromosomes. All metaphase I cells observed in female F1 hybrid x male H. longifilis had three complex bivalents consisting of 43.3% giant ring and 56.7% giant rod chromosomes. The number of ring bivalents per cell was higher in parental H. longifilis than parental C. anguillaris. The number of ring bivalents per cell increased from F1 (6.7 and 8.2) to F2 backcross (13.5) hybrid generations indicating increasing chromosomal instability of backcross hybrids over Fl and F2 hybrid

Techniques of producing monosex or sterile population of fish for aquaculture -- a review of selected literature

The need to develop techniques that can make the male grow faster in many species of fish as well as the female in some other species cannot be over-emphasized. Monosex culture of the faster growing sex can increase production if the method is reliable. The use of such techniques as manual sexing, sterilisation, hybridization, gynogenesis, androgenesis polyploidy and sex-reversal can provide solutions or partial solutions to the problems associated with sexual difference, sexual maturation and unwanted reproductio

Electromechanical Systems in Building Services Engineering

There are myriad of electromechanical systems in domestics, commercial and industrial buildings. Part or most of these systems hardware are hidden from the public though they do account for between 50% to 75% of the total construction cost and take up to 15% of the building volume. This paper is aimed at enumerating their functions as a prerequisite for designing (including modelling and simulation), selecting, integrating, managing and reduction in energy usage. The electromechanical systems included in this paper are cold and hot water supplies, heating, ventilation, air conditioning, drainage, sanitation, refuse and sewage disposal, gas, electricity, access control, communication, oil installation, fire fighting and transportatio

The informal sector and universal health coverage: crucial considerations

http://www.bu.edu/pardee/publications-library/issues-in-brief/issues-in-brief-no-37-june-2019/Published versio

What Casimir Energy can suggest about Space Time Foam?

In the context of a model of space-time foam, made by $N$ wormholes we discuss the possibility of having a foam formed by different configurations. An equivalence between Schwarzschild and Schwarzschild-Anti-de Sitter wormholes in terms of Casimir energy is shown. An argument to discriminate which configuration could represent a foamy vacuum coming from Schwarzschild black hole transition frequencies is used. The case of a positive cosmological constant is also discussed. Finally, a discussion involving charged wormholes leads to the conclusion that they cannot be used to represent a ground state of the foamy type.Comment: ReVTeX, 3 pages. Talk given at the Fifth Workshop on Quantum Field Theory under the Influence of External Conditions, Leipzig, September 10-14, 200

Embedding co-management: community-based fisheries resource management regime in Lake Victoria, Tanzania

This paper discusses fisheries management reforms through involving local level institutions (LLFI). It is based on studies which were undertaken on TanzaniaÆs Lake Victoria fishery where LLFIs were established through the formation of Local enforcement Units, later named Beach Management Units (BMU), between 1998 and 2002. The paper takes the view that the overfishing problems that confront TanzaniaÆs fisheries management authorities are best understood from a social science perspective. The argument is that most communitiesÆ values and institutions are embedded in their societies. The same is however, not true for externally originated management tools and systems as is the case with BMUs. This paper shows that the BMUs established between 1998 and 2002, were not sufficiently grounded in their socio-cultural environment and this led them to be unsustainable and ineffective. The paper demonstrates that this mismatch by examining the different historical and social contexts in which livelihoods such as fishing emerged and was carried out. These social contexts generated social values that explain the individual behaviour of community members. It is such values that communities always strive to maintain in any activity including fishing. Thus, when confronted with situations that threaten these values, communities strategize or negotiate ways to cope. The coping strategies of two communities riparian to the lake are discussed. The paper therefore proposes a framework for making these units æfitÆ local conditions in order to make them effective and sustainable so as to reform fisheries management.Fishery management

Kinetic and Transesterification Properties of Lipase from Sprouted Melon (Cucumeropsis manni) Seeds

Crude lipase (acetone powder) was extracted from freshly sprouted melon seeds (Cucumeropsis manni). The activity, kinetic properties (effect of time, pH, and enzyme and substrate concentration, respectively) as well as the ability of the crude lipase to catalyze the production of methyl esters (biodiesel) were examined. The enzyme activity was determined using n-hexane as the solvent (1:2 v/w solvent: substrate ratio) and the transesterification product was analyzed by HPLC. A linear relationship was observed between reaction time and rate of lipolysis with the optimal activity at 2hr of incubation. Furthermore, the lipase was optimally active at acid pH 5 and lipolysis was achieved optimally when the amount of enzyme was 2.0g. Rate of lipolysis was observed to increase linearly at concentrations up to 5.0g of substrate above which a drop in the rate, with no apparent decrease in activity, was observed. The Km (6.25g) and Vmax (13.33%FFA/hr) were also determined. Analysis of the transesterification product yielded 0.61% alkyl ester, 0.81 %FFA, 93.17% TAG, 4.15% 1, 3-DAG and 1.26% 1, 2-DAG while transesterification efficiency was determined to be at 0.588%. Biodiesel (alkyl esters) prepared with the crude lipase was had a density of 0.872 g/mL while its cloud and pour points were 22°C and 12°C, respectively. The results from this research showed that an active lipase was isolated from sprouted melon seeds. However, the fuel properties of the biodiesel produced did not meet international transportation fuel standards. In order to be used industrially, better reaction conditions need to be established for the lipase