Evaluation of the stressed-state of a bed based on emission memory effects of rocks in near-well space

Mining Institute, Moscow. Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 2, pp. 26–29, March–April, 1991.     

A solenoid-derived wiggler

A novel wiggler design for use in free-electron lasers (FELs) is proposed, consisting of a staggered array of magnetic poles situated inside the bore of a solenoid. The resultant field pattern consists of a periodic transverse magnetic field on axis, as well as a longitudinal guide field. Such a wiggler has several advantages: the longitudinal field acts to confine the electrons near the FEL axis, high fields can be attained at short wiggler periods, the field strength is easily varied, and fabrication and testing of the wiggler are relatively easy. It is planned to use this wiggler design in a far infrared FEL to be built at Stanford University     

On the capacity of a cellular CDMA system

It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity     

Heat transfers in treatment furnaces

For heat treating cylindrical metal billets, their lay-out in a furnace usually resembles that of an in-line heat-exchanger tube bank, with the air flows orthogonal to the billets. For maximum effectiveness of transferring thermal energy from the forced convecting air to the billets, the optimal horizontal pitch-to-diameter ratio for the billets should be 1·33 ± 0·05. For this same purpose it is advantageous to employ a vertical spacing (between the billets) as large as can be permitted for a given load of billets.     

Multivariable controller design in an adaptive control scheme

A multivariable control system design approach in the frequency domain is presented. The issue of control system redesign in an adaptive control scheme is discussed. Expert system techniques have been used for the automated design of controllers for multivariable systems. Design knowledge has been represented using rules, facts and objects. The design process consists of a sequence of operations obtained by heuristics and experience in the the design techniques. An automated design session of a multivariable plant using the expert system demonstrates that the expert system appears to work well in its prototype implementation.     

A finite-element method for creep calculations on structures

A form of the initial-strain method is proposed that implements a general equation of state for a material during creep. A noniterative exact method has been devised for incorporating the effects of temperature on the elastic properties in a finite-element calculation.Translated from Problemy Prochnosti, No. 4, pp. 8–13, April, 1992.     

PCAAD—an object-oriented expert system for assembly of printed circuit boards

Abstract: Electronics manufacturing is the fastest growing segment of the manufacturing domain today. The rapid change in printed circuit board manufacturing has been possible with the induction of surface-mounted components and robotic assembly. The high density packaging capability of surface-mounted technology has contributed enormously to the development of new trends in printed circuit board manufacturing.
PCAAD—Printed Circuit Board Assembly Advisor—is an expert system developed to capture this new technology and its interaction with the existing through-hole-mounting technology. In building the system, rules and guidelines pertaining to assembly are formulated and incorporated into the knowledge-base. The system is built on an object-oriented paradigm. The object-oriented approach, Smalltalk-80, the object-oriented language and the hierarchical rule structure paradigm are briefly discussed. A rating system is also introduced to rank various assembly designs. PCAAD can advise whether or not to proceed with assembly with a particular assembly design, and suggests assembly modification at the early stage of design to eliminate the assembly problems in the later phase of board production.