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This paper investigates the temporal inflow profile that minimises the total cost of travel for a single route. The problem is formulated to consider the case in which the total demand to be serviced is fixed. The approach used here is a direct calculation of the first order variation of total system cost with respect to variations in the inflow profile. Two traffic models are considered; the bottleneck with deterministic queue and the kinematic wave model. For the bottleneck model a known solution is recovered. The wave model proves more difficult and after eliminating the possibility of a smooth inflow profile the restricted case of constant inflow is solved. As the space of possible profiles is finite dimensional in this case, the standard techniques of calculus apply. We establish a pair of equations that are satisfied simultaneously by the optimal inflow and time of first departure.

In the paper the optimization procedure of a direct current motor with a hybrid excitation has been presented. The excitation system consists of a shunt field winding disposed around field pole and permanent magnet, both acting in parallel. The field distribution in motor for various magnet and field pole dimensions has been determined using finite element method. The flux linkage with the armature winding has been computed. Demagnetizing effect of armature current was taken into account. The optimal permanent magnet and the field pole dimensions, ensuring minimum total cost of purchase and work during assumed period of time were calculated. Motor characteristics e.g. rated torque, rated current, speed regulation limit were used as constraints. In worked up algorithm and computer program Carroll internal penalty function method was used. Some basic suggestions tor design of optimal hybrid excited dc motors with parallel permanent magnet and electromagnetic excitation are given.

Polymethacrylates are distinguished by transparency as well as by chemical and mechanical resistivity. This overview of the current status of the thermoplastic methacrylate solid resins discusses synthesis, production processes, binder characteristics, and major areas of application.

In the course of development of human communities towards industrially advanced societies of today, there have been changes not only in economic conditions in the majority of fields of human activity but also in the ways of providing for food, which went hand in hand with changes in living conditions. Large‐scale industrial production has brought about major changes in the way of life of the population. The development of industrial agglomerations results in a growing number of city dwellers, most of whom have no chance of producing foodstuffs of their own in kind. The distance between residential and industrial areas has been growing, the number of employed women has risen considerably. These are but a few factors affecting the way of boarding, particularly in households.

The purpose of this paper is to present findings of research on the level of health and safety (H&S) awareness and implementation in Botswana's construction industry.

A questionnaire survey was conducted on construction projects to establish the level of awareness and implementation of construction H&S. Physical observations were also conducted on construction sites in order to relate questionnaire responses to what actually obtained on construction sites. The study was limited to Gaborone and the immediate surrounding areas.

Findings from the research reveal that the level of H&S awareness is low, H&S legislation is not complied with, the management of contractors is not committed to H&S implementation, there is a lack of H&S management systems, procedures, and protocol, and clients and designers do not participate in the implementation of H&S.

The importance of construction H&S has been recognised by various researchers. This paper provides an insight on the level of awareness and implementation of H&S in Botswana's construction industry and should be viewed in the context of an effort to improve H&S.

12,2 Millionen Bundesbürger sind über 60 Jahre alt. Im Jahre 2000 werden es bereits 14 Millionen sein. Kein Wunder also, dass die Senioren für viele Wirtschaftszweige immer interessanter werden. Dies gilt auch für die Tourismusbranche, die mit der wachsenden Reisefreude der älteren Generation rechnen kann. Im vorliegenden Beitrag werden ausgewählte Ergebnisse einer Studie wiedergegeben, die das Institut für Freizeit‐ und Tourismusberatung aus Ettlingen Anfang des Jahres gemacht hatte.

Hotelry and Tourism can be considered as synonymous especially when looked at in small‐state, developing‐country terms, in that, in these small economies, without tourism, there can be no hotels and without hotels, nos tourism. Of course this is evident in both developing and developed countries that are dependent on tourism for their economic wellbeing, but it is certainly more marked in the former, especially the island state, where, as it were, hotels were and are still constructed dependent on the fact that tourism already exists in the country and the country has the potential for tourism growth. In other words the rationale for hotel development is based on the state of the tourism product in the developing territory, and this is usually dependent on outside marketing forces from the developed nations, as there is little or no domestic tourism in these small countries to merit the growth of the hotel plant. Therefore, the growth and potential of the industry is dictated usually by countries to the north and their influence on the culture and the habits of the developing host nation (usually to their south) is oftentimes enormous.

The purpose of this paper is to consider the impact on architects of recently introduced Construction Regulations in South Africa.

Given the passing of the first anniversary of the promulgation of the Construction Regulations, a survey was conducted to determine the perceptions of member practices of the South African Institute of Architects.

Findings include: the traditional project parameters in the form of cost, quality, and time are still perceived to be substantially more important than health and safety (H&S); the manifestations of the impact of the Construction Regulations are wide spread – increased H&S awareness predominates among the manifestations, followed by increased consideration for H&S by most stakeholders, and H&S predominates in terms of the extent to which the Construction Regulations will impact on various project parameters.

The paper offers a valid argument for the inclusion of construction H&S to feature more prominently in architectural education and training programmes.

I‐V characteristics of GaAs n‐i‐n structures are calculated by considering impact ionization of carriers. Impact ionization at reverse‐biased n‐i junction becomes a cause of steep current rise when an acceptor density in the i‐layer is high. It is shown that an optimum acceptor density exists to keep a good isolation. Photoconduction transients of GaAs n‐i‐n structures are also simulated, and are shown to be strongly affected by existence of n‐i junctions.

THE rapid growth and development of the aircraft industry has necessitated prompt decision and action in handling the many problems in connexion with the erection and equipment of aerodrome buildings, hangars, workshops and factories. In the urgency of providing the industry with all its varied requirements, it is not surprising that lire insurance planning has to a very large extent been crowded out. There are, no doubt, several reasons for this and in the welter of plans and designs that have been drawn and re‐drawn, the necessity of complying with the clients' requirements, numerous rules and regulations of local authorities and Acts of Parliament, etc., the benefits which accrue to wise planning from a fire insurance point of view have not always been fully appreciated. The need for increased output has in many cases pressed very heavily on those making the necessary preparations, and frequently no serious thought has been given to fire insurance planning. There are some persons who are under the impression that, having conformed with the numerous rules and requirements, they have carried out all that can be done in this direction.