Structural efficiency

If, in service, a material is required to have a certain strength in order to perform its function satisfactorily then a useful way to compare the structural efficiency of a range of materials is to calculate their strengdi desirability factor. 

We usually must go beyond the simple concept of a monocoque or single-thickness skin for whatever structure we design. That is, we must usually consider the bending stiffness, and, to achieve structural efficiency, we often must stiffen a structure in some manner. We will first address the terminology of stiffening and how it is used. Then, we will consider the types of stiffeners that could be used. Next, an important issue that arises in the design of stiffeners is whether the stiffener has an open- or a closed-cross section. Then, we will address some of the... 

In this section we discuss the idea of degrees of freedom of motion of simple structures, with emphasis on space frames and trusses. These simple structures are often easily understood and exhibit simple and predictable behavior. They can also be structurally efficient and thus make a valuable group of structures interesting in astronomy. 

Many factors influence how a policy is implemented and whether it achieves its objectives effectively. Experience in policy implementation in many areas indicate the importance of good organization. A number of organizational attributes, such as a sound structure, efficient procedures, well-trained personnel and adequate financial resources, are considered cmcial for effective policy execution (18, 19, 20, 21). 

A Novel Algorithm Based on a Parallel-Rotation Move for Generating Polymer Structures Efficiently... 

Though the fabrication cost is low, flat ends are not a structurally efficient form, and very thick plates would be required for high pressures or large diameters. 

The first and third order terms in odd powers of the applied electric field are present for all materials. In the second order term, a polarization is induced proportional to the square of the applied electric field, and the. nonlinear second order optical susceptibility must, therefore, vanish in crystals that possess a center of symmetry. In addition to the noncentrosymmetric structure, efficient second harmonic generation requires crystals to possess propagation directions where the crystal birefringence cancels the natural dispersion leading to phase matching. 

Strengthening of the connections is often the most cost effective upgrade for existing buildings if it does not require removal of existing interior walls and equipment. For a member to absorb blast energy and be structurally efficient, it must develop its full plastic flexural capacity. This requires a substantial increase in shear capacity at the connections to avoid failure. 

Berkessel and co-workers synthesized a library of structurally diverse tertiary amine-functionalized catalyst candidates incorporating a chiral 1,2- or 1,4-diamine chiral backbone [231, 232, 246]. Structure-efficiency studies through sequential modification of the diamine backbone, the tertiary amine functionality, the (thio) urea N-substituents as well as of the amide substituent pattern, exemplarily illustrated a Jacobsen-type 1,2-diamine-based structure (figure 6.24), identified... 

C9-epi-122 98% conv. (99% ee) after 30h, respectively (Figure 6.40). This structure-efficiency relationship supported the results already published by the Soos group for quinine- and quinidine-derived thioureas (Figure 6.39) [278]. C9-epimeric catalysts were found to be remarkably more efficient in terms of rate acceleration and stereoinduction than the analogs of natural cinchona alkaloid stereochemistry. This trend was also observed for the corresponding (thio)ureas derived from DHQD as shown by the experimental results in Figure 6.40 [279]. 

Maintaining Functional and Structural Efficiency in Packed Towers... 

Scheme 8. Mo-catalyzed tandem ARCM can be used to synthesize seven-membered carbo-and heterocyclic structures efficiently and in optically enriched form...

As was described in Chapter 3, the structures of metals are determined by the various ways to efficiently pack spheres. With regard to structures, efficiency refers to minimizing the amount of free (empty) space in the structure and maximizing the number of atoms that are in simultaneous contact (the extent of metallic bonding). Three of the most common ways to arrange spherical atoms are shown in Figure 18.1. 

Carbon and graphite fibers are made by the pyrolysis of certain naturally occurring and man-made fibers, such as regenerated cellulose (rayon) fibers. A wide range of physical, mechanical and chemical properties may be obtained dependent on amount of dehydration. This product is one of the most structurally efficient reinforcements. Unlike any other reinforcement, it retains its 2,800 MPa (400,000 psi) tensile strength when tested up to a temperature of 2700 C (4800F). 

Although many improvements have been proposed for the calculation of the dielectric response function from first principles [31,32], still this stage is both computer time and memory very demanding when a large basis set is used for the description of the electronic structure. Efficient GW methods have thus been developed, in which a model dielectric function is used to mimick the screening properties of the system under study [28,33,34]. 

The crossing oj between the reactant s ground state PEC and that of the radical product, allows the establishment of the following structure-efficiency relationships (i) an increase in coupling decreases of triplet reactions when but will have no effect when > E (ii) in a reaction series, the formation of less stable radicals or a reduction of will lower E and may increase because will increase relative to E (iii) in a reaction series, the reduction of d caused by transition state stabilization lowers E and may reduce (iv) does not depend on deuteration (v) singlet states are less efficient that triplet states (vi) of Type II reactions may increase with solvent polarity. 

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