The availability and binding of heavy metals in compost derived from household waste

Organic waste can be recycled as compost which has traditionally been used as a soil improver. As more waste is recycled as compost, it is becoming increasingly important to find alternative uses for compost. Leachability data are used to determine the environmental availability of Cd, Cu, Pb, and Zn contained in natural compost. Batch sorption data are used to determine uptake of additional Cd, Cu, Pb, and Zn by compost and assess its potential use in remediation work, as an alternative to natural materials such as peat. The relative binding of these additional metals to compost is found to be in the order Pb > Cd ≈ Cu > Zn. The sorption of metals on compost takes place, at least in part, by exchange of calcium bound to the compost and there is evidence that the sorption occurs in both humic and non‐humic sites in the compost. The use of compost to bind metals in remediation work is discussed. © 1999 Society of Chemical Industry     

State-of-the-art report on use of nano-materials in concrete

Nanotechnology application to concrete presents an innovative approach to improve concrete properties based on the ability to manipulate the cementitious material at an atomic scale. This paper presents a review of the nano-materials that have been used in concrete. The literature survey revealed that four nano-materials are most often used to modify concrete properties; these include nano-silica (nano-SiO₂), nano-titanium dioxide (nano-TiO₂), carbon nano-tubes (CNTs) and carbon nano-fibres (CNFs). All of these four nano-materials have shown improvement in many concrete properties. Both nano-TiO₂ and nano-SiO₂ reduce bleeding and segregation, and improve mechanical and transport properties. CNFs and CNTs tend to adversely affect the fresh properties due to agglomerations, which are overcome when a surfactant or ultrasonic mixer is used. However, both CNFs and CNTs significantly improve the mechanical properties of concrete. This paper also discusses how concrete durability is improved when nano-materials are added to concrete. In addition, this paper identifies several research needs based on the gaps in the current state of knowledge on using nano-materials in concrete.     

Explaining quantitative systems to uninitiated users

The importance of explanation in expert systems has been documented from the early days of their development; there is an equally pressing need for explanation in systems that employ a decision-making process based on quantitative reasoning. This is particularly necessary for users who do not have a sophisticated understanding of the formal apparatus that the system employs to reach its decisions. In order to generate meaningful answers to questions asked by such unsophisticated users, an explanation facility must translate the formal structures of the problem solving system into the concepts with which the user understands the problem domain. Previous work on the explanation of quantitative systems is based on the assumption that the user has at least a basic grasp of the formal approach of the problem solving system. However, in realistic application situations, it is more likely the case that in order for the human user to understand why a mathematically-based advice-giving system makes the suggestions that it does, the problem solving rationale of the system must be explained in the user's own terms, which are typically different from those of the mathematical system. To develop an explanation methodology that is capable of justifying the results of a system based on quantitative reasoning to an uninitiated user, we employ a representation that enables our explanation facility to translate the abstract mathematical relationships that make up a quantitative system into the domain-specific concepts with which a typical user approaches the problem solving task. In our system, the process of generating explanations, therefore, involves translating one set of concepts into another. An added feature of this system is that it is capable of providing explanations from two perspectives: that of the quantitative problem solving system, and that of the human user who is familiar with the domain problem but not with the mathematical approach. We have implemented this approach to explaining quantitative systems by creating an explanation facility for a problem in the manufacturing domain. This facility responds to user queries about a scheduling system that uses a mathematically-based heuristic to choose jobs for an annealing furnace.     

Template-Based Gait Authentication Through Bayesian Thresholding

While gait recognition is the mapping of a gait sequence to an identity known to the system, gait authentication refers to the problem of identifying whether a given gait sequence belongs to the claimed identity. A typical gait authentication system starts with a feature representation such as a gait template, then proceeds to extract its features, and a transformation is ultimately applied to obtain a discriminant feature set. Almost every authentication approach in literature favours the use of Euclidean distance as a threshold to mark the boundary between a legitimate subject and an impostor. This article proposes a method that uses the posterior probability of a Bayes' classifier in place of the Euclidean distance. The proposed framework is applied to template-based gait feature representations and is evaluated using the standard CASIA-B gait database. Our study experimentally demonstrates that the Bayesian posterior probability performs significantly better than the de facto Euclidean distance approach and the cosine distance which is established in research to be the current state of the art.      

The Use of Partial Residual Plots in Regression Analysis

This paper defines partial residuals in multiple linear regression. The ith partial residual vector can be thought of as the dependent variable vector corrected for all independent variables except the ith variable. A plot of the ith partial residuals vs values of the ith variable is proposed as a replacement for the usual plot displaying ordinary residuals vs the ith independent variable. This partial residual plot shows the extent and direction of linearity, while displaying deviations from linearity, such as outliers, inhomogeneity of variance, and curvilinear relationships. Some alternative definitions of partial residuals are described.     

The Seniors’ Outdoor Survey (SOS Tool): comparing ratings and reliability between Italy and the USA

To test applicability of an environmental assessment instrument in new settings, the ratings and reliability of the SOS Tool were compared in diverse settings with a similar climate: Milan, Italy; and Bryan/College Station, Texas, USA. This instrument evaluates physical environment support for outdoor usage by residents at senior facilities. Two trained raters assigned ratings (using a 1–7 scale) to the 60 instrument items at each setting (Italy: 94 outdoor spaces, 67 facilities; US: 22 outdoor spaces, 12 facilities). Overall mean ratings were similar across both sites (6% difference), and three of the five domains had comparable mean ratings. Mean inter-rater reliability was good in both settings but higher in Italy (ICC = .97 versus .82). Despite geographic/cultural differences, mean ratings for most items and domains were surprisingly similar between Italy and the US. This finding, and the high inter-rater reliability found in both settings, suggest this instrument may be useful in a wide range of settings.