Productivity and ergonomic investigation of bent-handle pliers

Awkward wrist posture is generally considered an occupational risk factor for hand/wrist disorders, leading to the ergonomic design principle of "bend the tool, not the wrist." Sixteen participants performed a computer jumper installation task and a simple assembly task while productivity, wrist posture, and shoulder posture were measured. The work surface orientation (vertical and 45 degrees) and the level of constraint placed on the user (constrained grip and unconstrained grip) were also varied. The results indicate that the beneficial effects of the bent-handle pliers are task dependent. In the computer jumper task the bent-handle pliers resulted in 5.3% faster task performance, whereas in the assembly task performance was 4.9% faster with the straight-handle pliers. The bent-handle pliers reduced shoulder deviations by 50% in the jumper installation task, and ulnar deviation was reduced by 12% and 22% for the jumper installation task and the assembly task, respectively (all significant at p < .05). However, allowing participants to hold the pliers in a grip configuration of their choosing (unconstrained technique) often reduced these postural benefits. In applying these results to workplace design activities, one should recognize that the ergonomic utility of bent-handle pliers can be considerable but that the 3-D kinematics characteristics of the task must be considered.     

Electrodeposited nickel–manganese: an alloy for microsystem applications

A process has been developed, using LIGA fabrication techniques, for the electrodeposition of a high strength, heat resistant Ni–Mn alloy to meet the requirements of a mechanical microsystem component. The electrolyte bath chemistry consists of Ni sulfamate to which a small amount of manganese chloride is added. The Mn content for the electrodeposited alloys of interest is generally equal to or less than about 1 wt%. It is shown that its co-deposition with Ni is insensitive to feature aspect ratio and therefore not limited by mass transport effects, permitting uniform alloy deposition. While plating of this alloy at a constant current density yields a high strength deposit, it also results in a highly stressed film that makes the fabrication of thick section deposits problematic.To counter this, a pulsed deposition scheme is employed to fabricate a nanostructured film consisting of alternating nm-thick regions of low stress, relatively soft Ni, and high strength, and highly stressed, NiMn alloy. This moderates the high plating stress of the NiMn alloy and enables the deposition of thick deposits. Yield strengths of over 800 MPa are achievable in the pulse-plated material, with good as-plated ductility (6%). The material loses only about 15% of its original strength after a one hour, 600 °C anneal, and no embrittlement is observed since no sulfur-bearing additives are employed. To the contrary, ductility measured as strain to failure is improved.The authors thank the Sandia/California LIGA prototyping team for their assistance in the fabrication of the masks, molds and sample preparation needed to execute the work described here. Colleagues at Sandia/New Mexico are acknowledged as well for their contribution to some of the mechanical testing and microscopy.This work supported under contract DE-A04–94AL85000     

High-temperature instrumented microscale compression molding of Pb

Compression molding of Pb plates with LiGA (Lithographie, Galvanoformung, Abformung) fabricated Ni microscale mold inserts was carried out in the temperature range of 100–300 °C. In-situ measurements of compressive molding force, demolding friction force and insert displacement were carried out with a custom-built, high-vacuum, high-temperature, instrumented molding machine. Microscale features generated on Pb plates and insert condition after repeated molding runs were examined. The in-situ force monitoring capability enabled compressive stresses needed for molding and frictional stresses generated by demolding to be measured as a function of temperature. Our results demonstrate that, in cases where no significant metal/insert chemical interactions exist, present LiGA fabricated Ni inserts possess adequate mechanical properties for repeated micromolding of low melting temperature metals.We gratefully acknowledge partial project support from NSF through grant DMI-0124441, Louisiana Board of Regents through contracts LEQSF(2001–04)-RD-A-07 and LEQSF(2000–03)-RD-B-03. Ni inserts used in this work were purchased from Mezzo Systems Inc.     

Selective detection and identification of sugar nucleotides by CE-electrospray-MS and its application to bacterial metabolomics

A novel method employing CE-ESMS and precursor ion scanning was developed for the selective detection of nucleotide-activated sugars. By using precursor ion scanning for fragment ions specific to the different nucleotide carriers, i.e., ions at m/z 322 for cytidine monophosphate, m/z 323, 385, and 403 for uridine diphosphate, m/z 362, 424, and 442, for guanosine diphosphate, and m/z 346, 408, and 426 for adenosine diphosphate, it was possible to selectively detect sugar nucleotides involved in the biosynthesis of glycoconjugates such as glycoproteins and lipopolysaccharides. Enhancement of sensitivity was achieved using N-(2-hydroxyethyl)piperazine-N'-(2-ethanesulfonic acid) as a sample stacking buffer and provided detection limits between 0.2 and 3.8 pmol.mL(-)(1). The present CE-ESMS method provided linear dynamic ranges over the concentrations 0.2-164 nM (r(2) = 0.952-0.997) for different nucleotide sugar standards. The application of this method is demonstrated for the identification of intracellular pools of sugar nucleotides in wild type and isogenic mutants from the bacterial pathogen Campylobacter jejuni. By using product ion scanning (with and without front-end collision-induced dissociation), it was possible to determine the precise nature of unexpected sugar nucleotides involved in the biosynthesis of pseudaminic acid, a sialic acid-like sugar previously observed on the flagellin of some pathogenic bacteria.     

Sodium oxacillin in the horse: serum, synovial fluid, peritoneal fluid, and urine concentrations after single-dose intramuscular administration

Six healthy adult mares were given a single dose (25 mg/kg of body weight) of sodium oxacillin IM. Oxacillin concentrations in serum, synovial fluid, peritoneal fluid, and urine were measured serially over a 48-hour period. The mean peak serum oxacillin concentration was 9.75 microgram/ml at 0.5 hour after injection. Mean peak oxacillin concentrations in synovial and peritoneal fluids were 1.45 microgram/ml and 2.60 microgram/ml at 1 hour and 2 hours, respectively. These concentrations decreased in parallel with serum values and were not measurable at 48 hours. Urine concentrations of oxacillin were high, with a mean peak concentration of 2,790.2 microgram/ml at 0.5 hour.     

A note on upwinding and anisotropic balancing dissipation in finite element approximations to convective diffusion problems

In one dimension, Petrov—Galerkin nonsymmetric weighting for the convective diffusion equation can be interpreted as an added dissipation. The addition of an appropriate amount of dissipation can therefore give the same oscillation-free solutions as the ‘unwinding’, Petrov—Galerkin, finite element methods. The ‘balancing dissipation’ is optimally chosen so that excessive dissipation does not occur. A scheme is presented for extending this approach to two-dimensional problems, and numerical examples show that the new method can be used with improved computational efficiency.     

The yield,fatty acid composition and physical properties of milk fat obtained by feeding soya oil to dairy cows

The presence in the bovine mammary gland of a desaturase specific for the conversion of stearic to oleic acid allows the manipulation of the physical properties of milk fat by varying the dietary intake of C₁₆ and C₁₈ fatty acids. In particular, feeding the dairy cow an oil with a high C₁₈: C₁₆ ratio should allow the proportion of milk fat that is liquid at 5°C to be increased, with a consequent improvement in the low-temperature spreadability of butter. In this paper, the effect of feeding concentrate rations containing (a) soya oil as the free oil and as cracked soya beans; (b) various levels of soya oil, the ration being offered twice or 24-times daily, on the thermal properties of the milk fat and on the yield of milk constituents is examined in detail. Feeding ratios containing free soya oil greatly increased the proportion of milk fat liquid at 5°C, whereas cracked soya oil gave only slight increases. Proportion and yield of milk fat were decreased by feeding soya oil twice daily but were increased by continuous feeding.     

Docking of sulfonamides to carbonic anhydrase II and IV

Starting with a known active site of a protein and a database of compounds, one would like to quickly identify a few compounds that "dock" into the active site and obtain "good" binding free energies. The main goal of current automated docking procedures is to predict the "best" substrate-enzyme complex while other programs such as UHBD and DelPhi can be used to compute binding free energies. In this paper, we will focus on the application of docking methods and parameters to study substrate-enzyme interactions of a metalloenzyme system. Specifically, we report on the docking of sulfonamides to carbonic anhydrase II and IV, which are of interest due to their application in glaucoma therapy. Using a standard docking protocol, it is possible to correctly predict not only the orientation of inhibitors to a specific isozyme, but also determine the qualitative affinity for a group of inhibitor for an isozyme.     

Developing artificial neural networks for safety critical systems

There are many performance based techniques that aim to improve the safety of neural networks for safety critical applications. However, many of these approaches provide inadequate forms of safety assurance required for certification. As a result, neural networks are typically restricted to advisory roles in safety-related applications. Neural networks have the ability to operate in unpredictable and changing environments. It is therefore desirable to certify them for highly-dependable roles in safety critical systems. This paper outlines the safety criteria which are safety requirements for the behaviour of neural networks. If enforced, the criteria can contribute to justifying the safety of ANN functional properties. Characteristics of potential neural network models are also outlined and are based upon representing knowledge in interpretable and understandable forms. The paper also presents a safety lifecycle for artificial neural networks. This lifecycle focuses on managing behaviour represented by neural networks and contributes to providing acceptable forms of safety assurance.