The awareness and practice of value management by South African consulting engineers: Preliminary research survey findings

The awareness of value management (VM) and the nature and extent of its practice by professional civil, electrical and mechanical engineers in the South African construction industry are investigated using a web-based, online questionnaire survey as the first part of a more extensive investigation. A primary objective of the early study is to test the UK-based assertion of Kelly et al. [Kelly, J., Male, S., Graham, D., 2004. Value Management of Construction Projects. Blackwell, Oxford] that VM is an established service with commonly understood tools, techniques and styles. The survey findings suggest that, while awareness of VM is reasonably prevalent among South African engineers, its practice is considerably less extensive. Where VM is undertaken, almost no attempt is made to benchmark VM activities against international standards nor does its use appear to conform to any standard methodology. Engineers prefer other ways of delivering value to projects, and do not generally employ VM to facilitate the client briefing process. The findings are important given the increasing globalization of construction services, especially given the international ties between designers, project managers and other professionals. Professional engineering associations in South Africa should adopt a proactive role in promoting the use of VM by engineers, possibly through continuing professional development programmes.     

Estimating life cycle plant maintenance costs

The financial success or otherwise of a maintenance strategy can be determined realistically only when actual costs are compared with target ‘predicted’ values. This is because, in the absence of accurate cost control mechanisms, maintenance expenditure can exceed capital cost. In order to address this problem, a methodology is presented for predicting life cycle maintenance expenditure over the useful life of tracked hydraulic excavators. First, time series analysis (using a moving centred average) illustrates that the trend in maintenance cost expenditure is difficult to isolate due to large perturbations in periodic unscheduled maintenance. Such expenditure accounts for 92% of total maintenance cost. Second, cumulative costs of maintenance are modelled using a cubic equation, with time (in hours) as the predictor (x_n) variable. Model performance is robust with a coefficient of determination (R²) of 0.99 and a mean percentage error (MPE) of minus 3.94. The paper concludes with direction for future research in this field, particularly with respect to expanding the model's application to machines of various weights, manufacturers and machines operating in other industries, and determination of criteria with which to predict when a plant item will reach the end of its useful life.     

Work stressors, role-based performance, and the moderating influence of organizational support.

As a test of the 2-dimensional model of work stressors, the present study proposed differential relationships between challenge stressors and hindrance stressors and role-based performance, which were expected to be moderated by organizational support. In a sample of 215 employees across 61 offices of a state agency, the authors obtained a positive relationship between challenge stressors and role-based performance and a negative relationship between hindrance stressors and role-based performance. In addition, organizational support moderated the relationship between challenge stressors and role-based performance but did not moderate the relationship between hindrance stressors and role-based performance. This suggests that organizations would benefit from increasing challenges in the workplace as long as they are supportive of employees and removing hindrances. Further implications for organizational theory and practice are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The role of classroom quality in ameliorating the academic and social risks associated with difficult temperament.

The present study examines the moderating role first grade classroom quality may have on the relations between children's difficult temperament (assessed in infancy) and their academic and social outcomes in early elementary school (first grade). Using data from the National Institute of Child Health and Human Development's Study of Early Child Care and Youth Development, 1032 children were rated by their mothers at 6 months of age on difficult temperament. The quality of first grade classroom environments were then observed and rated along three domains: emotional support, classroom organization, and instructional support. Regression analyses examined the statistical interactions between difficult temperament and classroom quality domains on children's academic and social outcomes. Results indicate high-quality classroom environments may ameliorate the academic and social risks associated with having a difficult temperament. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Mixed-mode correlator for micropower acoustic transientclassification

A mixed-mode very large scale integration (VLSI) processor for acoustic transient classification performs a running correlation between a time-frequency decomposed analog input signal and a corresponding template. Differential encoding of the inputs allows simplification of the multiply-and-accumulate operations, operating on binary templates and positive-valued inputs, implemented in current mode with eight MOS transistors per cell including SRAM template storage. The use of a bucket-brigade device (BED) instead of a charge-coupled device (CCD) for shift-and-accumulate operations allows long integration times necessary for acoustic transients spanning several hundred milliseconds. Correlated double sampling at the output compensates for dark current losses in the BED and other common-mode effects. The 64×16 time-frequency correlator measures 700 μm×1170 μm in a 1.2-μm CMOS process and dissipates an average of 30 μW in continuous operation     

Sustainability of Scottish water quality in the early 21st century

This paper reviews some of the current water quality issues relating to the surface waters of Scotland and highlights some of the key issues likely to be significant over the next decade. The sustainable management of water quality requires an appreciation of the temporal and spatial assessment of the resource, together with an identification of reference or natural conditions from which to determine change, and the elucidation of the drivers of change. Only through this integrated approach, can appropriate management strategies be developed and prioritised, bearing in mind that impacts may be decoupled from sources in both time and space. This paper highlights recent trends in water quality (from a hydrochemical perspective) with separation into three broad groups: rivers, lochs and estuaries. For rivers, a general reduction in concentration of determinants that are more indicative of urban point sources (phosphorus, ammonium, suspended solids, biochemical oxygen demand etc.) is apparent, while in more agriculturally-dominated areas, an increase in concentration of solutes that are considered more diffuse in origin, (e.g. nitrate) is reported. The increasing contribution to total loads from diffuse pollutants is a priority area for both research and policy. Current scientific challenges are to define the most appropriate spatial context within which regional water quality issues can be monitored and managed. It is likely that future emphasis will be placed on making an initial ecoregion based grouping in conjunction with physically defined catchment, which will be used to quantify site-specific impacts. Such an organisational approach will provide a mechanism that enables a targeted monitoring strategy to be developed. This will allow the establishment of ecologically based targets for water quality, and an improved understanding the biogeochemistry of pollution reversibility and ecosystem recovery. It is also fundamental to the development of tools through which to predict the time scale and magnitude of any recovery, such that environmental benefit can be optimised against realistic socio-economic constraints. The inter-relations between water quality objectives and the development of legislation for water resources management in Europe are discussed.     

Relationships among team ability composition, team mental models, and team performance.

This study examined the relationship between the similarity and accuracy of team mental models and compared the extent to which each predicted team performance. The relationship between team ability composition and team mental models was also investigated. Eighty-three dyadic teams worked on a complex skill task in a 2-week training protocol. Results indicated that although similarity and accuracy of team mental models were significantly related, accuracy was a stronger predictor of team performance. In addition, team ability was more strongly related to the accuracy than to the similarity of team mental models and accuracy partially mediated the relationship between team ability and team performance, but similarity did not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inferential structure of the NEO Five-Factor Inventory: Construct validity of the Big Four personality clusters.

Four studies investigated the dimensionality of the NEO Five-Factor Inventory (NEO-FFI; P. T. Costa & R. R. McCrae, 1992). In Study 1, four inferential dimensions and four clusters represented the NEO-FFI when 114 undergraduates freely sorted items into categories. Construct validity for four item-clusters derived from the inferential space was obtained in Study 2 based on self-report with 304 undergraduates. Study 3 validated these inferential clusters using self and peer reports for 420 undergraduates. Study 4 validated the cluster scales for predicting quality of life and significant social and cultural behaviours for 110 undergraduates. Implications for implicit personality theory, the number of dimensions issue in personality, and test construction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A bistable viologen‐TiO2 color switch

Abstract— The electro‐optical characteristics of a pixel configuration used in electrochromic viologen‐TiO₂ passive‐matrix devices are studied. The configuration has two stable color states in an intermediate voltage regime. Color switching is performed by applying voltages outside this regime. The bistability is due to electrolyte‐additive controlled electron trapping in the color‐changing viologen molecules.     

Electrostatically actuated metal-droplet microswitches integrated on CMOS chip

The dominance of surface tension over inertia in microscale and favorable scale effect for electrostatic actuation allow electrostatically driven metal-droplet systems practical. Because of such potential advantages as low contact resistance, naturally bistable operation, and high switch density, the liquid-metal droplet switch is an excellent candidate for reconfigurable circuit interconnections. Following earlier droplet microswitch examples and related studies of metal-droplet behavior, we report the first functioning droplet switch directly integrated on top of a functional CMOS circuit. While the surface tension dominance makes the droplet switches practical as a mechanical system and also brings bistability, it also requires a high electric field to move the droplet. We implement the concept of physical surface modification to lower the driving voltage to a value that a commercial CMOS process can provide. Unlike previous droplet switches, the reported device is planar-processed to allow the integration with the underlying CMOS circuits. The integrated switch is made functional by such provisions as self-limiting actuation and by optimizing the electrostatic force in the planar configuration and avoiding liquid-metal "flooding" into surface patterns. A fabrication process for low driving voltage and high compatibility is developed to integrate the droplet switch on the custom-developed CMOS chip. A packaging method adapted from well-established microelectronic packaging isolates the active switch space from the surrounding environment. Low driving voltage (as low as 15 V) and millisecond switching speed are achieved by the current on-chip device. While the current device uses /spl sim/150 /spl mu/m droplets for demonstration, additional theoretical and experimental results indicate that further miniaturization would lead to smaller devices and lower operation voltage.