Food conversion efficiency and the von Bertalanffy growth function. Part II and conclusion: Extension of the new model to the generalized von Bertalanffy growth function

The simple model relating food conversion efficiency (K sub(1)) to body weight derived from the theoretical concepts behind von Bertalanffy's growth model, is extended here in the context of Pauly's generalization of that model. The exponent, which was fixed to 1/3 in the simple model, is in the extended model equivalent to 1-d, with d being the weight exponent of the anabolism term in Pauly's growth model. This makes the model applicable to fish for which the assumptions of the original (special) version of von Bertalanffy's growth model are violated.

Role of fisheries extension officers in FFDA at Balasore

The first FFDA in Orissa state was established in the year 1976. The study was conducted in Balasore district of the State. The findings revealed that all of the FEOs were not well qualified but trained and experienced. The duration of training obtained varied from 3 to 10 months. An FEO has a large area under his jurisdiction. Cycle was used by most of the FEOs to visit the fish farmers which resulted in infrequent visits. The FEOs were not satisfied with the working conditions, promotion avenues and conveyance facilities. There was interference of political bodies in leasing out ponds. The amount of loan sanctioned was not adequate to start fish farming. They also revealed that marketing aspects were totally neglected by the FFDA.

The influence of peel angle on the mechanics of peeling flexible adherends with arbitrary load-extension characteristics

The peel test is commonly used to determine the strength of adhesive joints. In its simplest form, a thin flexible strip which has been bonded to a rigid surface is peeled from the substrate at a constant rate and the peeling force which is applied to the debonding surfaces by the tension in the tape is measured. Peeling can be carried out with the peel angle, i.e. the angle made by the peel force with the substrate surface, from any value above about 10° although peeling tests at 90 and 180° are most common. If the tape is sufficiently thin for its bending resistance to be negligibly small then as well as the debonding or decohesion energy associated with the adhesive in and around the point of separation, the relation between the peeling force and the peeling angle is influenced both by the mechanical properties of the tape and any pre-strain locked into the tape during its application to the substrate. The analytic solution for a tape material which can be idealised as elastic perfectly-plastic is well established. Here, we present a more general form of analysis, applicable in principle to any constitutive relation between tape load and tape extension. Non-linearity between load and extension is of increasing significance as the peel angle is decreased: the model presented is consistent with existing equations describing the failure of a lap joint between non-linear materials. The analysis also allows for energy losses within the adhesive layer which themselves may be influenced by both peel rate and peel angle. We have experimentally examined the application of this new analysis to several specific peeling cases including tapes of cellophane, poly-vinyl chloride and PTFE. © 2005 Elsevier Ltd. All rights reserved.

Towards a mathematical system for extension education

A system of equations describing the relationship of change agent in extension education and client (e.g. a leader of a local community) is presented. The main task of the former is to ensure that he is able to transfer information to the latter, also learning difficulties involved and passing them into institutions of higher learning.

Towards a mathematical system for extension education - II

A brief description is given of a mathematical model for use in extension education regarding fisheries in developing countries.

Study of the relative effectiveness of extension methods in educating fisherwomen

Three experimental groups from three different fishing villages were selected and administered with three extension treatments on two messages, namely, production of fish wafers and fish pickles. There was a significant knowledge gain in the subjects taught through different extension methods. It was observed that lecture aided with slides induced maximum knowledge followed by lecture aided with charts and lecture alone. Among all, the young and highly educated women gained maximum knowledge.