Portability of three consumer products

Three consumer products (a television set, a personal computer and a typewriter), all considered portable by their respective manufacturers, were evaluated experimentally for portability. Products were not considered portable if the physical and subjective workloads resulting from carrying them over specified distances were excessive. Twenty-two males and six females participated in the experimental investigation and carried the three products for distances of 45·72, 91·44. 137·16 and 182·88 m. Their pulse and ratings of perceived exertion (RPE) of the arms and whole body were recorded and used as measures of physical and perceived workloads. Both physiological and subjective responses to carrying products were significantly influenced by the type of product and carrying distance, regardless of the gender of the person performing the carrying. The results of this study and the design guidelines provided in the literature for one-handed and two-handed carrying tasks led to the conclusion that, of the three products, only the television set could be considered portable.     

An approximate expression for the motional capacitance of a lateral field resonator

A simple approximate expression is obtained for the motional capacitance of a lateral-field quartz resonator. Comparison with measured values for fundamental-mode and third-overtone SC-cut resonators shows agreement within 10-50%     

Effect of block weight on work demands and physical workload during masonry work

The effect of block weight on work demands and physical workload was determined for masons who laid sandstone building blocks over the course of a full work day. Three groups of five sandstone block masons participated. Each group worked with a different block weight: 11 kg, 14 kg or 16 kg. Productivity and durations of tasks and activities were assessed through real time observations at the work site. Energetic workload was also assessed through monitoring the heart rate and oxygen consumption at the work site. Spinal load of the low back was estimated by calculating the cumulated elastic energy stored in the lumbar spine using durations of activities and previous data on corresponding compression forces. Block weight had no effect on productivity, duration or frequency of tasks and activities, energetic workload or cumulative spinal load. Working with any of the block weights exceeded exposure guidelines for work demands and physical workload. This implies that, regardless of block weight in the range of 11 to 16 kg, mechanical lifting equipment or devices to adjust work height should be implemented to substantially lower the risk of low back injuries.     

Experimental tests of a novel Raman cell for vacuum ultraviolet generation to below Lyman-α

A novel-type Raman cell especially suitable for the generation of tunable vacuum ultraviolet (VUV) radiation with pump radiation from a frequency-doubled dye laser is described. This hydrogen-filled Raman cell permits the generation of narrow-bandwidth radiation to below 114 nm. Absolute VUV energies in the various anti-Stokes orders and measurements of pulse durations and pressure dependences are given.     

Stimulation of Phospholipase A2 by Toxic Main Group Heavy Metals: Partly Dependent on G-proteins?

Organometals induce platelet aggregation and inorganic metal ions such as Cd(2+) or Pb(2+) sensitise human blood platelets to aggregating agents and this action is associated with the liberation of arachidonic acid and eicosanoid formation. The same mechanism is observed using human leukaemia cells (HL-60) when treated with MeHgCl or Et(3)PbCl. The fatty acid liberation within human platelets and HL-60 cells could only be inhibited with phospholipase A(2) inhibitors of different specificity.Preincubation of the cells with pertussis toxin reduces the activation induced by Et(3)PbCl to a great extent. The non-catalytic B subunit, that only mediates the binding of the toxin to the cell membranes, has no effect at all. When summarised, these results suggest that one possible mechanism for the stimulation of phospholipase A(2) by Et(3)PbCl functions via a G-protein dependent pathway.     

A new fuzzy regression algorithm

A new fuzzy regression algorithm is described and compared with conventional ordinary and weighted least-squares and robust regression methods. The application of these different methods to relevant data sets proves that the performance of the procedure described in this paper exceeds that of the ordinary least-squares method and equals and often exceeds that of weighted or robust methods, including the two fuzzy methods proposed previously (Otto, M.; Bandemer, H., Chemom. Intell. Lab. Syst. 1986, 1, 71. Hu, Y.; Smeyers-Verbeke, J.; Massart, D. L. Chemom. Intell. Lab. Syst. 1990, 8, 143). Moreover, we emphasize the effectiveness and the generality of the two new criteria proposed in this paper for diagnosing the linearity of calibration lines in analytical chemistry.     

Imaging performance of annular apertures. 5: Total and partial energy integral functions

The total energy integral functions for apodization T1 = (1 - r2)n and T2 = (2r - r2)n are compared for unobstructed apertures. The energy values increase linearity for T2 and with the (2n + 3) power for T1. For obstructed apertures, these values for T1 increase with higher powers at small image radii and assume linear characteristics only at larger radii. This transition occurs as the obstruction approaches zero. Partial energy functions for a region centered some distance from the central region show the same general trend as the image irradiance functions.