Evaluation of a Two-Dimensional Conductivity Function Based on Boundary Measurements

This paper is concerned with an inverse problem for the conduction of heat in a two-dimensional domain. It seeks to recover the subsurface conductivity profile based on the measurements obtained at the boundary. The method considers a temporal interval for which time-dependent measurements are provided. It formulates an optimal estimation problem which seeks to minimize the error difference between the given data and the response from the system. It uses a combination of the zeroth-order and the first-order Tikhonov regularization to stabilize the inversion. The method leads to an iterative algorithm which, at every iteration, requires the solution to a two-point boundary value problem. A number of numerical results are presented which indicate that a close estimate of the thermal conductivity function can be obtained based on the boundary measurements only. [S0022-1481(00)00902-6]

Multiple stud shear connections in deep ribbed metal deck

This paper summarizes the results of push-out tests conducted on 17 different types of shear connections simulating three distinct components of a composite floor system: (1) an interior beam (perpendicular metal deck), (2) a spandrel beam (perpendicular metal deck), and (3) a girder (parallel metal deck). Each push-out specimen had a layer of 152 × 152 WM9.1 × WM9.1 welded wire mesh at mid-depth of each concrete slab.Two composite beams, each with ribbed shear connections typical of those in two of the types of push-out specimens representing ribbed shear connections in interior composite beams with ribbed metal deck, were tested with third-point loads over a simply supported span. Using the average ultimate shear strengths of the push-out specimens having the same configurations as the ribbed shear connections in the composite beam tests to calculate the ultimate flexural capacities of the composite beams resulted in a very close estimate of the measured ultimate flexural capacities of the composite beams. The average measured static yield strengths of the flanges and webs of the wide-flange sections used in the composite beam tests were included in the calculations of the ultimate flexural capacities of the composite beams. Key words: composite, push-out, ultimate shear, shear stud, ribbed metal deck, deep rib.

Growth sequences of finite groups IV

The main result is that d(Ssm) = n+2 for every finite non-abelian two-generator simple group S of order s and every integer n > 0. This is applied to give a very close estimate on d(Gn) for any finite group G whose simple images are two-generator. The article is based on the author's previous papers with similar titles.

Estimation of the Duration of Post-partum Amenorrhea among Nepalese Mothers: Some Indirect Techniques

The main aim of this paper is to use some indirect techniques to estimate the duration of post-partum amenorrhea (PPA) among Nepalese mothers by using the data of Ministry of Health (MOH 2001,2006). The techniques used are based on two types of data, i.e., duration of PPA and breastfeeding (BF). Among the techniques, the one developed by Aryal (2008) provided a very close estimate of the duration of PPA period among Nepalese mothers. The estimated average PPA period was found to be 11.8 months against the observed value of 11.1 months in 2001 data (MOH 2001) while it was 10.3 months against the observed value of 9.3 months in 2006 data (MOH 2006). Estimated PPA period was found to be much close especially by fitting the inverse and logarithmic models. In addition to this, duration of PPA period was also estimated in relation to the characteristics of mothers and the results were found to be consistent with the observed values. It is therefore the used techniques provided very close estimate of PPA period, which might be an applicable technique to estimate the duration of PPA period for any population if the data of the duration of breastfeeding are available.Key words: Post-partum amenorrhea; Breastfeeding; Indirect-technique; Curves fitting; FertilityDOI: 10.3126/njst.v10i0.2963Nepal Journal of Science and Technology Vol. 10, 2009 Page: 213-218

Elastic-plastic failure loads of plane frames

When deformations become finite, the load factor required to produce rigid-plastic deformation of a plane frame under proportional loading differs from the load factor at collapse as given by simple plastic theory. The effect of all work terms involving the squares of member rotations is investigated and a simple formula derived. The effect of finite deformations on the load capacities of elastic-plastic frames is then studied. It is shown theoretically that, if certain approximations are made, the Rankin© load, based on the rigid-plastic failure load and the lowest critical load, give a close estimate of the actual failure load of such a structure. The nature of the approximations made to arrive at this result shows under what circumstances the Rankine load cannot be expected to provide a close estimate of failure. Experimental and theoretical results illustrating the degree of correlation are presented and discussed.

The Soviet Power Play at Changkufeng

Power politics and opportunism go hand in hand. Picking the right time to act involves a clear perception of the alternatives, a close estimate of the risks, and a clever gamble on the odds.The Russians have shown themselves adept at the game. Their use of force or the threat of force has been unusually astute. They try to move when the deck is stacked in their favor.

On the natural frequencies of vibrating systems

The basic problem of Vibration Theory is to calculate for a given system the modes and associated frequencies of its “normal” free oscilla­tions. These are components into which the whole motion can be resolved when the system vibrates freely, and through small distances, about its position of equilibrium. Each one is wholly independent of every other, and has its own (in general) distinct phase and frequency, which are common to all parts of the system. Relatively to one another the amplitudes of different parts are invariant, but the phase and magnitude of a normal oscillation are not (in theory) restricted. Exact calculation is difficult even when attention is confined to the gravest (i. e. lowest) natural frequency, and on that account great value attaches to a theorem of Lord Rayleigh whereby a close estimate of this frequency can be based on a comparatively rough assumption in regard to the corresponding mode. It is known that the result will err, if at all, in the direction of over-estimation : if then by equally simple calculations it were possible to obtain a second figure close to it and known to be an under-estimate , such knowledge would for practical purposes be very nearly as useful as an exact result.