Design philosophies

The HlFi system allows the designer to move interactively from one level of specification to another, either in a top-down or in a bottom-up manner. The top-down direction typically starts out from a behavioral specification of the problem (described in chapter 2) and refines it to a structure of lower level behaviors according to a chosen algorithm. 

1 Array Versus Element It is often suggested that design of a broadband array starts with the development of a single element with large bandwidth. 

This argnment does in no way contradict the fact that most stored energy is located in the immediate vicinity of the elements. Recall (see Sections 4.8-4.10 in reference 1) it is directly associated with the evanescent waves that decrease exponentially bnt are still felt at a typical distance of A./4 from the elements. Thus, if the interelement spacing typically is 0.3X, the storage space is limited to 0.15k. 

Finally, the designer should be reminded that the element spacing should always be sufficiently small to avoid grating lobes and surface waves in dielectric slabs adjacent to the dipole elements. 

The fast variation with frequency as observed in the spiral array is typical for elements consisting of long wires (namely in this case the two arms of the 

3 The Moving Groundplane (That Moves Too Fast ) We considered above an array of spirals in front of a groundplane. We observed how the antenna reactance Xa was incompatible with the groundplane impedance Zi+ and therefore would not lead to a consistently lower VSWR. However, one may 

The final area of concern is to develop a practical design philosophy for composite structures. Is there a philosophy that will enable us to account for and accommodate all the essential behavioral characteristics of composite materials Can we do it without getting bogged down in overly complicated issues  

Section 7.8 is on design philosophy for composite structures to explore some relatively simple and practical approaches to achieve an 

Each of the preceding topics is addressed in the followm ections of this chapter. Remember, this is only a brief introduction to the amazing and complex area of design of composite structures. Thus, detail must be kept subservient to the overall concepts. 

Land reclamation projects are undertaken for various purposes and under varying conditions. The performance requirements imposed on a fill depend on the future use of the reclamation and, hence, they vary for each individual project. 

Boundary conditions are often site and project specific as well. Physical site conditions, such as wave climate, currents, water depth, subsoil properties and the vulnerability of the environment to dredging and reclamation activities will differ from one site to another. The quahty and quantity of the fill available for construction will strongly depend on the location of the project. These conditions will not only affect the design of a reclamation, but they must also be taken into account when selecting the most suitable dredging equipment and construction method. 

A rational design must integrate the functional and performance requirements considering the boundary conditions of the project in order to adequately specify the geometry and properties of the fill mass. The same rationality must be applied with respect to the construction of the reclamation requiring an appropriate selection of equipment and working method. 

A functional requirement defines what a system must do, while a performance requirement specifies something about the system itself and how well it performs its function. A fill mass (and its subsoil) can be regarded as a system with functional and performance requirements. 

The functional requirements and the design of the superstructures (i.e., their Ultimate Limit State and/or Serviceability Limit State, see section 8.4.1) lead to performance requirements of the fill mass such as maximum allowable settlement of the superstructures (buildings, roads, storage areas, runways, revetments, tunnels, etc.), and sufficient safety against slope failure or liquefaction. The required basic mass properties like strength, stiffness, density and permeability can be derived from these performance requirements. 

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Evbuomwan, N. F. O., Sivaloganathan, S. and Webb, J. 1996 A Survey of Design Philosophies, Models, Methods and Systems. Proc. Instn Mech. Engrs, Part B, 210(B4), 301-320. 

The design philosophy behind the fixed-base drive circuit is to draw current from a relatively low voltage source (3 to 5 V) which is usually provided by an auxiliary winding on the power transformer. The resistor directly in series with the base (R2 as shown in Figure 3-33) should be on the order of 100ohms. Its... 

Current production aircraft include bonded structure designed up to 20 years ago as well as more recent designs on newer aircraft or derivatives. Materials, processes and design philosophy for metallic bonded structure have remained relatively stable over that period, while composite bonded structure has advanced significantly. Both will be reviewed and contrasted in the following sections. 

Favorable operational economics and good management practices require high levels of control of the ozonation system. Depending on the specific process of ozone applications, plant size, and design philosophy, the control system may be simple or complex. The trend in Europe is toward highly sophisticated and centralized control. 

El-Halwagi, A. M. and El-Halwagi, M. M. (1992). Waste minimization via computer aided chemical process synthesis—A new design philosophy, TESCE J., 18(2), 155-187,... 

The first problem area of the so-called anisotropic analysis will be broken down into two subareas shear-extension coupling and bend-twist coupling. We have already observed for the most complicated laminate in the design philosophy proposed earlier that the A,q and A26 stiffnesses are both zero. There is no shear-extension coupling in the context of that philosophy. However, in contemporary composite structures analyses, it is relatively easy to include the treatment of shear-extension coupling, so you should not be overwhelmed by that behavioral aspect or by the calculation of its influence. 

In this case the design was not at fault. The operators did not understand the design philosophy. Would this have been foreseen in a hazard and operability study (Section 18.7), and would special attention have been paid to the point in operator training ... 

On both platforms the ergonomics of layout and instrumentation would hinder rapid and effective response to a significant fire or gas release. The overall ergonomics in both control rooms betrayed the lack of a coherent human-machine interface design philosophy being implemented within the design process. 

Many aspects of FCC development have been the result of trial and error. The development of present design standards is as much art as it is science. Consequently, it is appropriate to review some of the key developments that have influenced the current design philosophy behind the FCC reactor and regenerator ... 

Despite the market explosion of data management software, there are still situations which justify in-house development. When it is appropriate to develop software In-house, design philosophies such as those Implemented in the MARS system will help reduce the development and maintenance investment and enhance the effectiveness of the system. 

The pilot plant stage Is vital in the scale-up of any new resin process, and in this paper we discuss the design philosophy of pilot plants and then describe two fully Instrumented and computer data logged reactors. Some indication is given of the use of the extracted data for both modelling and scale up. Both controlled and data logged parameters are tabulated and an example of data extraction for heat balance is illustrated. 

Phillips of the BHR Group, UK, provides a compact definition of process intensification, saying it is ... a design philosophy whereby the fluid dynamics in a process are matched to its chemical, biological and/or physical requirements,. .. [27]. In this way, significant benefits are gained, those listed above. 

The most complex automated systems are used almost exclusively by centralized HTS operations in large pharmaceutical companies and are referred to as ultra HTS (uHTS) platforms. They typically consist of the same four functional instruments, but have the capacity to process several hundred plates per extended workday. They often incorporate a modular design philosophy with multiple duplicate instruments for enhanced capacity that offer some functional redundancy. The mechanism for moving plates from one instrument module to another is often, but not always, a continuous track-way that resembles an industrial assembly line rather than the robotic arm typically used in a workcell system [5-8],... 

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