Microsomal and photochemical oxidation of aflatoxin B1

The UV irradiation (lambda = 362 nm) of aflatoxin B1 (AfB1) dissolved in water resulted in the formation of an oxidized product. The process was not inhibited by ionol, a routine inhibitor of the radical processes. The oxidized product was not found in the system where AfB1 was metabolized by the 3-methylcholanthrene-activated rat liver microsomes. It is suggested that the product is identical with 2,3-dihydrodiol of AfB1.     

Optimum design of steel frames with stability constraints

Optimum design algorithms based on the optimality criteria approach are proven to be efficient and general. They have the flexibility of accomodating variety of design constraints such as displacement, stress, stability and frequency in the design problem. The design methods developed recently, although considering one or more of these constraints, lack the necessity of referring to any relevant design code. The algorithm presented for the optimum design of street frames implements the displacement and combined stress limitations according to AISC. The recursive relationship for design variables in the case of dominant displacement constraints is obtained by the optimality criteria approach. The combined stress inequalities which include in-plane and lateral buckling of members are reduced into nonlinear equations of design variables. The solution of these equations gives the values of bounds for the variables in the case where the stress constraints are dominant in the design problem. The use of effective length in the combined stress constraints makes it possible to study the effect of the end rigidities on the final designs. The design procedure is simple and easy to program which makes it particularly suitable for microcomputers. A number of design examples are considered to demonstrate the practical applicability of the method. It is also shown that the design procedure can be employed in selecting the optimum topology of steel frames.     

Optimal size,hydraulic retention time and volatile solids loading rate of biogas unit using water hyacinth

With a view to evaluate the effects of hydraulic retention time and volatile solids loading rate on methane production using water hyacinth, experiments were conducted in a 160 dm³ capacity, well-mixed continuous digestion unit at ambient temperature. The optimal design of biogas plant using water hyacinth was elucidated, to provide a unit giving a maximum methane yield of 0.16 nm³ kg^?1 volatile solids added, which was 60% greater than the conventional plant using cowdung. The calculations of optimal design factors were based on reactor size, hydraulic retention time and volatile solids loading rate; considerations were made of capital cost, running costs and operational revenue.     

Learning vector quantization for the probabilistic neural network

A modified version of the PNN (probabilistic neural network) learning phase which allows a considerable simplification of network structure by including a vector quantization of learning data is proposed. It can be useful if large training sets are available. The procedure has been successfully tested in two synthetic data experiments. The proposed network has been shown to improve the classification performance of the LVQ (learning vector quantization) procedure.     

A compositional approach to multiparadigm programming

The author points out that although different aspects of a system require different approaches, programmers are confined to their language's one paradigm. Multiparadigm programming makes it possible to match the paradigm to the problem. The potential of paradigm composition as an approach to multiparadigm programming is explored. In paradigm composition, a multiparadigm program is written as a collection of single-paradigm programs. The single-paradigm programs are composed, which means that they execute concurrently and cooperatively to form the whole of a functioning system. Interactions between paradigms are defined at the conceptual levels of the participating paradigms. The case of a small prototype telephone network is considered as an example of paradigm composition.<>     

Nonlinear superposition in saturation recording of disk media

The magnetic readback signal is generally assumed to be made up of linearly superposed single transition responses. As the transition spacing is reduced, this property is seen not to hold, With particulate disks, we find the head signal can be reconstructed as a linear superposition of variably spaced individual transitions, while with cobalt alloy film disks, both the spacing and the amplitude of individual transitions vary as a function of the data. This behavior is interpreted by a self consistent 2D recording model, linear superposition improves dramatically with lowM_{r}tdisk media.     

Uncertain fuzzy models and their applications: III. Optimal estimation

The quality-estimation and decision-making criteria based on the values of error possibility likelihood measures, error necessity likelihood, error possibility confidence, and error necessity confidence are considered. The criteria are formulated for the adequacy of an uncertain fuzzy (UF) model and conclusions based on the UF model for the object under investigation and the UF observation model.     

Space asymptotic method for the study of neutron propagation

Space asymptotic theory is shown to be a suitable model for the study of pulsed experiments in neutron multiplying systems. After a short revisitation of the basic aspects of space asymptotic theory applied on the Laplace transformed one-group transport equation, the full solution is derived. It is shown how results are exact in representing localized pulse propagation in the first portion of the transient, until the boundary is reached by the neutron signal, since it propagates with a finite velocity. Approximate models are then derived starting from the exact formulation and the B_N method is used to account for anisotropy effects. Numerical results are presented for one-dimensional systems, discussing the physical phenomena and noting the distortions introduced by approximate models, which may then turn out to be inadequate for the simulation of realistic pulsed experiments situations.