An analysis of the structure of fish marketing and distribution in Kwara State of Nigeria

A study was conducted examining the structure of fish marketing in Kwara State and also the conduct of participants within the market structure. The performance of the marketing system was evaluated, highlighting bottlenecks in the system and means of overcoming them

The power of fish trader associations in the marketing of fish in Lagos State

This paper focusses on the activities of trade associations in the marketing of fish in Lagos State. The study covers 6 different markets in Lagos State of Nigeria. Analysis indicates that 86% of the traders are members of the associations. The ages of the traders range from 21 to over 55 years. However, majority are between the ages of 31 and 45 years. Traders secure their initial capital mostly from trade associations and Esusu/Ajo. Most traders have no working capital to maintain a regular series of outlets, so wholesalers turn to associations for funds, while retailers turn to wholesalers. They eventually pay back when they sell to consumers. The fish industry is found to be imperfectly competitive mostly because of the actions of fish trader associations. The fish marketing system is highly personalised and loyality exists between wholesalers and retailers and their customers

Improved sampling techniques for the direct simulation Monte Carlo method

The direct simulation Monte Carlo (DSMC) method is a widely used approach for flow simulations having rarefied or nonequilibrium effects. It involves heavily to sample instantaneous values from prescribed distributions using random numbers. In this note, we briefly review the sampling techniques typically employed in the DSMC method and present two techniques to speedup related sampling processes. One technique is very efficient for sampling geometric locations of new particles and the other is useful for the Larsen-Borgnakke energy distribution.

Direct numerical simulation of hypersonic boundary layer transition over a blunt cone with a small angle of attack

The direct numerical simulation of boundary layer transition over a 5° half-cone-angle blunt cone is performed. The free-stream Mach number is 6 and the angle of attack is 1°. Random wall blow-and-suction perturbations are used to trigger the transition. Different from the authors’ previous work [Li et al., AIAA J. 46, 2899(2008)], the whole boundary layer flow over the cone is simulated (while in the author’s previous work, only two 45° regions around the leeward and the windward sections are simulated). The transition location on the cone surface is determined through the rapid increase in skin fraction coefficient (Cf). The transition line on the cone surface shows a nonmonotonic curve and the transition is delayed in the range of 0° ≤ θ ≤ 30° (θ = 0° is the leeward section). The mechanism of the delayed transition is studied by using joint frequency spectrum analysis and linear stability theory (LST). It is shown that the growth rates of unstable waves of the second mode are suppressed in the range of 20° ≤ θ ≤ 30°, which leads to the delayed transition location. Very low frequency waves VLFWs� are found in the time series recorded just before the transition location, and the periodic times of VLFWs are about one order larger than those of ordinary Mack second mode waves. Band-pass filter is used to analyze the low frequency waves, and they are deemed as the effect of large scale nonlinear perturbations triggered by LST waves when they are strong enough.The direct numerical simulation of boundary layer transition over a 5° half-cone-angle blunt cone is performed. The free-stream Mach number is 6 and the angle of attack is 1°. Random wall blow-and-suction perturbations are used to trigger the transition. Different from the authors’ previous work [ Li et al., AIAA J. 46, 2899 (2008) ], the whole boundary layer flow over the cone is simulated (while in the author’s previous work, only two 45° regions around the leeward and the windward sections are simulated). The transition location on the cone surface is determined through the rapid increase in skin fraction coefficient (Cf). The transition line on the cone surface shows a nonmonotonic curve and the transition is delayed in the range of 20° ≤ θ ≤ 30° (θ = 0° is the leeward section). The mechanism of the delayed transition is studied by using joint frequency spectrum analysis and linear stability theory (LST). It is shown that the growth rates of unstable waves of the second mode are suppressed in the range of 20° ≤ θ ≤ 30°, which leads to the delayed transition location. Very low frequency waves (VLFWs) are found in the time series recorded just before the transition location, and the periodic times of VLFWs are about one order larger than those of ordinary Mack second mode waves. Band-pass filter is used to analyze the low frequency waves, and they are deemed as the effect of large scale nonlinear perturbations triggered by LST waves when they are strong enough.

Investment opportunity in aquarium technology. Export marketing of tropical aquarium fishes

A brief account is given of the demand for ornamental fish, providing also estimates of world trade volume. The major importing countries are the USA, Japan, Germany, the UK and the Netherlands. Present supply patterns are outlined; although Nigeria has vast natural resources of tropical aquatic life and the right climate for breeding, current exports are estimated at only 5% of the total potential. Recommendations for the promotion of exports of tropical aquarium fish in Nigeria are included

Two-Phase Flow In Anode Flow Field Of A Small Direct Methanol Fuel Cell In Different Gravities

An in-situ visualization of two-phase flow inside anode flow bed of a small liquid fed direct methanol fuel cells in normal and reduced gravity has been conducted in a drop tower. The anode flow bed consists of 11 parallel straight channels. The length, width and depth of single channel, which had rectangular cross section, are 48.0, 2.5 and 2.0 mm, respectively. The rib width was 2.0 mm. The experimental results indicated that when the fuel cell orientation is vertical, two-phase flow pattern in anode channels can evolve from bubbly flow in normal gravity into slug flow in microgravity. The size of bubbles in the reduced gravity is also bigger. In microgravity, the bubbles rising speed in vertical channels is obviously slower than that in normal gravity. When the fuel cell orientation is horizontal, the slug flow in the reduced gravity has almost the same characteristic with that in normal gravity. It implies that the effect of gravity on two-phase flow is small and the bubbles removal is governed by viscous drag. When the gas slugs or gas columns occupy channels, the performance of liquid fed direct methanol fuel cells is failing rapidly. It infers that in long-term microgravity, flow bed and operating condition should be optimized to avoid concentration polarization of fuel cells.

Un modelo normativo de marketing medioambiental estratégico orientado a la obtención de ventajas competitivas

XXXIV, 581 p.

Direct observation of adsorption sites of protein impurities and their effects on step advancement of protein crystals

We measured noninvasively step velocities of elementary two-dimensional (2D) islands on {110} faces of tetragonal lysozyme crystals, under various supersaturations, by laser confocal microscopy combined with differential interference contrast microscopy. We studied the correlation between the effects of protein impurities on the growth of elementary steps and their adsorption sites on a crystal surface, using three kinds of proteins: fluorescent-labeled lysozyme (F-lysozyme), covalently bonded dimers of lysozyme (dimer), and a 18 kDa polypeptide (18 kDa). These three protein impurities suppressed the advancement of the steps. However, they exhibited different supersaturation dependencies of the suppression of the step velocities. To clarify the cause of this difference, we observed in situ the adsorption sites of individual molecules of F-lysozyme and fluorescent-labeled dimer (F-dimer) on the crystal surface by single-molecule visualization. We found that F-lysozyme adsorbed preferentially on steps (i.e., kinks), whereas F-dimer adsorbed randomly on terraces. Taking into account the different adsorption sites of F-lysozyme and F-dimer, we could successfully explain the different effects of the impurities on the step velocities. These observations strongly suggest that 18 kDa also adsorbs randomly on terraces. Seikagaku lysozyme exhibited a complex effect that could not alone be explained by the two major impurities (dimer and 18 kDa) present in Seikagaku lysozyme, indicating that trace amounts of other impurities significantly affect the step advancement.

An appraisal of the efficiency of fish marketing system in Lake Chad basin

Fish products from the Chad Basin Lake play important role in meeting fish protein needs of Nigeria: they contribute not less than 25% of the total domestic fish supply and are significant in determining the availability of processed products and reduction of post-harvest losses. Processors, marketers and consumers are the major actors in appraising a marketing system. The results show that most sellers (4-7.5%) are within the age range of 30-39 years. Desires for more earnings led the markets to diversify their business activities to food stuff trading (37.5%), dried meat/livestock sales (37.5%), farming (12.5%), and transportation (12.5%). 65% of traders dispose off their products mostly in the mornings and evenings, 70% of the products are sold smoked while 50% of products are sold to individual consumers. Lake Chad fish products have a long distribution chain. There is also a high degree of buyers and sellers concentration in the primary fish markets and secondary (urban) markets. The products have a vertical regional movement with southern traders (82.5%) dominating the business, thus making the products popular all over Nigeria. Product differentiation with imperfect pricing policy is common occurrence. Lake Chad fish marketing system has distortions that impede its efficiency, recommendations are made on how to ensure a better efficiency of the system

Marketing and distribution of fish from Lake Chad

This study provides information on fish quantities, economic data and flows of Doro fish market near Baga, Nigeria, known as the major fish market on the Nigeria section of the Lake Chad

The role of women in marketing of frozen fish in Lagos State of Nigeria

The involvement of women in the marketing of frozen fish in Lagos State (Nigeria) was examined in this study. Two hundred questionnaires were administered to fish marketers in five markets randomly selected within the Lagos metropolis based on their storage capacities. These markets were Balogun (500 tones), Idumagbo and Idumota (250 tonnes each) Obalende and Epetedo (37.5 tonnes each). From the study results, a greater percentage of women (64.2%) are actively involved in marketing of frozen fish in the study areas. Over 56% of these traders are retailers while about 33% are wholesalers. More than 91% of the marketers were found to be literate. A high percentage of the frozen fish are imported (68%), 27% from coastal fishing and 5% from riverine fishing. The commonest fish in the markets were titus (34%), sardine (32%), hake 19%, catfish 10% and argentine 5%. Catfish has the highest profit margin. The greatest problem of these traders is the lack of modern storage facilities and where available, the erratic power supply constitutes a problem

Direct measurement of entrainment in plasma jets

The entrainment rate of ambient gas into a turbulent argon plasma jet generated by plasma torch is directly measured using a “porous-wall chamber” technique. It is shown that with the increase of the mass flow rates of argon at the jet inlet, the mass flow rate of entrained gas increases. The normalized mass flow rate decreases with the increasing inlet mass flow rates of plasma torch. The entrained gas mass flow rate increases with increasing chamber length, but less depends on the arc current of the plasma torch at higher flow rates. The effects of different ways of inflowing gas into plasma torch on entrainment characteristics of plasma jet are also examined in this paper.