Improved Loading Capacity Research Articles

Design of adaptive structures for improved load capacity

Design of adaptive structures for improved load capacity

Shoes and insoles for patients with rheumatoid foot disease.

Pedorthic devices (shoes, modifications, insoles) are alternatives to, and, complementary with, operative procedures for patients with rheumatoid foot disease. The practical use of insoles and shoesole rolls (rocker soles) to diminish pressures and shearing stresses, and to support load bearing, is described. Criteria for prescribing such devices are described. The requirements for orthopaedic shoes are listed and a special technique of using test shoes with transparent thermomoldable stiff plastic materials is introduced to reveal pressure spots in advance of finishing the definitive shoe. Custom made pedorthic devices can improve loading capacity and mobility effectively even in severely deformed feet, thus being an important part of medical treatment.

Molecular Imprinting Utilizing an Amide Functional Group for Hydrogen Bonding Leading to Highly Efficient Polymers

In this paper we report the synthesis of molecularly imprinted polymers (MIPs) using an amide as the hydrogen-bonding functional group. All the amide MIPs made in this investigation exhibited good enantiomeric recognition of the imprinted species when evaluated by high-performance liquid chromatography (HPLC). Most of the amide MIPs were synthesized in a polar organic solvent (acetonitrile). By contrast, when a carboxyl group was used as the hydrogen-bonding functional group, MIPs made in acetonitrile exhibited only very weak recognition and in some cases no recognition at all with the print molecules tested. The amide MIPs also showed much improved load capacity. This suggests that for a number of cases the protocol described could be employed to reduce background, nonspecific binding compared to polymers using carboxyl groups, by avoiding an excess of negatively charged functionalities. It was shown that the tailing and peak asymmetry problems often associated with the use of MIPs in HPLC could be overcome by using linear gradient elution. The specificities of amide MIPs in terms of size, shape, and hydrogen-bonding selectivity were also investigated in detail. Finally, amide MIPs also showed good enantiomeric recognition in aqueous media.

A Thermohydrodynamic Analysis of Journal Bearings Lubricated by a Non-Newtonian Fluid

Our earlier work on the flow of a non-Newtonian fluid of the differential type in a journal bearing is extended here to include nonisothermal operations and temperature dependent viscosity. We show that for the type of lubricant investigated, even a slight departure from Newtonian behavior renders the bearing performance relatively insensitive to changes in lubricant temperature. But whether this change in lubricant behavior actually results in improved load capacity depends on the value and the sign of the material parameters.

Theoretical analysis and experimental investigation of a porous metal bearing

To improve the tribological behaviour of porous bearings a new type of self-lubricated porous metal bearing is introduced with special non-uniform distribution of permeability. It has been manufactured using a practical production process, its local permeability varying regularly along its circumference. Theoretical analysis and experimental investigation show that: the new bearing has lower friction and higher load capacity than that of ordinary porous bearings, and there is no initial temperature rise and friction increase with the new bearing. The limiting pV(tested) value of the new bearing is about 200% that of an ordinary porous bearing. Considering non-uniform permeability and the effects of curvature, cavitation and velocity slip, a modified Reynolds equation for the oil film and lubrication equation for the porous matrix are derived. A numerical solution for the equations is obtained. Some aspects of the lubrication mechanism in porous bearings and ways of improving load capacity are also discussed.

Load capacity of oilfilm—Lubricated ball-bearing with spiral grooves

In order to improve load capacity and stability of a fluid moving-pressure bearing, at present, measure of cutting grooves on a turning-shaft is generally adopted.

The Dual Action Gas Thrust Bearing—A New High Load Bearing Concept

The principle of utilizing hydrodynamic effects in diverging films for improving load capacity in gas thrust bearings is discussed. A new concept of dual action bearing based on that principle is described and analyzed. The potential of the new bearing is demonstrated both analytically for an infinitely long slider and by numerical solution for a flat sector shaped thrust bearing. It is shown that the dual action bearing can extend substantially the range of load carrying capacity in gas lubricated thrust bearings and improve their efficiency.

The Influence of Longitudinal and Transverse Profile on the Load Capacity of Pivoted Pad Bearings

An extension of previous work on the effects of surface profile on the load capacity of pivoted pad thrust bearings. Numerical solutions are presented for a square pad having profiles consisting of (a) longitudinal curvature, (b) transverse curvature, and (c) a combination of (a) and (b). Improved load capacity over the flat pad with optimum pivot location is found for some operating conditions including the case of the centrally pivoted pad.