Determination of loads applied perpendicularly to the outer boundary of a ring using coefficients of influence

A procedure is explained to determined the amount of several pairs of diametrical loads applied to the outside boundary of a ring when stresses at selected points of the inside or outside boundaries are known. Coefficients of influence are used, following an approach similar to the one presented in a previous paper. Examples of application are given and the possible increase in precision is shown when the number of points of measurements is larger than the number of loads to be determined.     

Thrust programs for minimum propellant consumption during the vertical take-off and landing of a rocket

In this paper, the thrust programs for minimum propellant consumption during vertical take-off and landing maneuvers of a rocket in a vacuum are derived for an arbitrary central gravitational field. It is shown that, regardless of the mathematical form of the attracting force, the extremal arc for take-off is composed of a maximum thrust subarc followed by a coasting subarc, and the extremal arc for landing is composed of a coasting subarc followed by a maximum thrust subarc.     

On the Huang Class of Variable Metric Methods

Several authors have created one-parameter families of variable metric methods for function minimization. These families contain the methods known as Davidon–Fletcher–Powell, Broyden–Fletcher–Goldfarb–Shanno, and symmetric rank one. It is shown here that the same one-parameter families of methods are obtained from the Huang update by requiring the update to be symmetric.     

Development of proposed federal standard 1070: 62.5/125-μm graded-index, multimode optical fiber waveguides for on-premises applications

This paper describes a process that has been successful in generating a specification to guide the user community in the procurement of single-size, multimode optical fiber for on-premises applications. This process began with an attempt to adopt an industry standard as a federal standard that would eliminate a multiplicity of choices available from the marketplace. The initial EIA-458-A Standard contained four “preferred” sizes. Discussions both in a government standards committee and in an applications-oriented industry (EIA) working group indicated the desirability of recommending a single fiber size. The process by which the industry committee selected the 62.5-μm core diameter/125-μm cladding diameter multimode fiber is presented.

The next element of the process was that of selecting the appropriate standard performance measures and attributes that would assure minimum performance of graded parameters such as attenuation and bandwidth, as well as a uniform specification of the product. The vehicle selected for this specification was the EIA 492-Series Generic, Sectional, and Blank Detail Specifications. Inputs were solicited from all of the identified U.S. manufacturers of this fiber size. Those inputs were coordinated and integrated into a detail specification, which is now being circulated by the EIA on a standards proposal ballot. After ballot approval, it will be published as an ANSIIEIA standard specification. Similar work has been initiated to develop a detail specification for fiber optic cables based on a related set (472-Series) of EIA specifications.

The process of developing a detail specification that assures conformance of the product to dimensional and strength tolerances as well as performance measures requires considerable coordination and iteration. No proprietary information or processes are contained in the specification so that the industry participants are free to compete on price and performance as long as compliance with the specification can be demonstrated.     

A new approach for the formation of fused cyclooctane or cyclohexane rings

The intramolecular regioselective addition of unsymmetrical allylsilanes to conjugated dienones is shown to permit facile entry into 5-6, 6-6, 5-8, and 6-8 bicyclic ring systems.     

On the photoisomerisation of 13-desmethyl-retinal

All mono-$\text{cis}$-isomers of 13-desmethyl-retinal have been prepared fro the alll-$\text{trans}$-compound by photoisomerisation. The various isomers were separated by HPLC and identified by their 400 MHz-¹NMR-spectra.     

The calculation of monocyclic molecular structures using MINDO/3

A comparison is made of the experimentally determined structures for some 4, 5, and 6 membered monocyclic rings and the MINDO/3 calculated structures. Among several systematic deficiencies the calculated ring structures are found to be too flat. This is attributed to the fact that MINDO/3 underestimates 1,4-eclipsing interactions.