Air purification by house plants : a literature survey

Within the project ‘Plant champion air purification’, a public-private cooperation, a literate survey was carried out to explore recent findings on the possibilities of plants to purify indoor contaminated air. Literature was searched in academic journals, on the internet and within reports recently carried out for the horticultural sector. Here this knowledge is shortly described. Plants generally have the capacity to assimilate hydrophilic Volatile Organic Compounds (VOCs) like formaldehyde without harm. Lipophilic VOCs are less well assimilated and follow different uptake pathways. Differences between plant species can sometimes be related to amount of leaves, wax layer composition, stomatal conductance or hairs. Apart from the green plant parts, the roots, the micro-organisms and rooting medium have a role in air purification. The research in plant chambers mainly generated knowledge on short term uptake of volatiles, but the uptake mechanisms and the long-term performances of plants are only partly understood. The research on upscaling of lab results to air purification in rooms within buildings is still in its infancy. A few good studies have been done and show promising results, but most research was statistically poor. More research is needed to extrapolate the findings from lab research to practice

GPS-Based Reduced Dynamic Orbit Determination Using Accelerometer Data

Currently two gravity field satellite missions, CHAMP and GRACE, are equipped with high sensitivity electrostatic accelerometers, measuring the non-conservative forces acting on the spacecraft in three orthogonal directions. During the gravity field recovery these measurements help to separate gravitational and non-gravitational contributions in the observed orbit perturbations. For precise orbit determination purposes all these missions have a dual-frequency GPS receiver on board. The reduced dynamic technique combines the dense and accurate GPS observations with physical models of the forces acting on the spacecraft, complemented by empirical accelerations, which are stochastic parameters adjusted in the orbit determination process. When the spacecraft carries an accelerometer, these measured accelerations can be used to replace the models of the non-conservative forces, such as air drag and solar radiation pressure. This approach is implemented in a batch least-squares estimator of the GPS High Precision Orbit Determination Software Tools (GHOST), developed at DLR/GSOC and DEOS. It is extensively tested with data of the CHAMP and GRACE satellites. As accelerometer observations typically can be affected by an unknown scale factor and bias in each measurement direction, they require calibration during processing. Therefore the estimated state vector is augmented with six parameters: a scale and bias factor for the three axes. In order to converge efficiently to a good solution, reasonable a priori values for the bias factor are necessary. These are calculated by combining the mean value of the accelerometer observations with the mean value of the non-conservative force models and empirical accelerations, estimated when using these models. When replacing the non-conservative force models with accelerometer observations and still estimating empirical accelerations, a good orbit precision is achieved. 100 days of GRACE B data processing results in a mean orbit fit of a few centimeters with respect to high-quality JPL reference orbits. This shows a slightly better consistency compared to the case when using force models. A purely dynamic orbit, without estimating empirical accelerations thus only adjusting six state parameters and the bias and scale factors, gives an orbit fit for the GRACE B test case below the decimeter level. The in orbit calibrated accelerometer observations can be used to validate the modelled accelerations and estimated empirical accelerations computed with the GHOST tools. In along track direction they show the best resemblance, with a mean correlation coefficient of 93% for the same period. In radial and normal direction the correlation is smaller. During days of high solar activity the benefit of using accelerometer observations is clearly visible. The observations during these days show fluctuations which the modelled and empirical accelerations can not follow

Session B6: Hydraulic Research on Fish Passage Design at Lock & Weir Sites

Abstract: Both European and Belgian legislations aim at restoring and enhancing the ecological strength of the water systems. Besides improvement of water quality and protection through legislation, restoration of free fish migration on the rivers and main waterways. To solve the problem of the disruption of longitudinal habitat connectivity by manmade obstacles such as locks and weirs, fish passages are constructed. In close cooperation with the Institute for Nature and Forest Research (INBO) of the Flemish Government (hydraulic) research on fish passage design at weir-lock sites on Flemish rivers has been done since 1995 at Flanders Hydraulic Research (FHR). The research is done via scale model tests, field measurements and literature study. To determine the effectivity of a fish passage both passability and attractiveness are assessed. The passability requires limitations to the maximum velocity and minimal depth along the fish passage. The attractiveness is defined as the extent to which fish can find the entrance of the fish passage. To obtain maximum attractiveness an attraction flow at the passage entrance is applied. The presentation gives an overview of the FHR research. Regarding the passability current results and research questions relating both nature like fish passages as bypass channels and more technical solutions as V-shaped fish ladders and vertical slot passages are addressed. Also previous research on swimming and leaping capacities that has been done with living fish is presented. In recent years several scale model tests have been done regarding the attractiveness of fish passages downstream of weirs applying a perpendicular attraction flow. Current research focusses on the comparison of perpendicular with parallel attraction flows and on sharp bends in Vshaped fish ladders

A critical consideration of ethical foundations for the accounting profession

When considering some of the key reasons for the desperate state of the current global economic environment, it is difficult to deny accounting’s role therein. Although accounting institutes require adherence to codes of conduct, the question remains as to what happened to the stewardship function of the accounting profession. This article has critically reflected on the question, ‘What constitutes an ethical accounting profession’? The key principles within many institutes’ codes of conduct, such as competency, integrity, objectivity and confidentiality, have been considered against the background of utilitarianism, formalism and virtue ethics as foundational ethical theories. This article has concluded that although these principles aim to provide a framework for ethical accounting conduct, individual subjectivity on the part of the accountant will play a role in how these ethical principles become ethical practices

Agromere: how to integrate urban agriculture in the development of the Dutch city of Almere?

Urban agriculture produces green city areas with as an extra dimension providing food, energy, care, education or recreation for the civilians. And thus it can contribute to a more sustainable and liveable cities. The objective of the project Agromere is to create a process which will lead to a new residential quarter where agriculture is fully integrated in city live. Agromere is situated in the fast growing city of Almere, the Netherlands. In a combined stakeholder and design process a township is designed which integrates living (5,000 inhabitants) with urban agriculture on 250 ha. During this process an enthusiastic network of stakeholders has been established which developed innovating and unique ideas on urban farming. The potential for organic farming in the city is high because of its emphasis on animal welfare and consumer relations

Structuring of breeding objectives in the pork supply chain in South Africa

Pig production is a techno-scientific internationalized business that is continuously exposed to change and risk. Changes in the Agri-Business are inter alia caused by changes in globalization, information technology, biotechnology and changes in consumer trends. The consumer, within the framework of the pig supply chain, is fundamental to this study. Hence an in depth review of meat market surveys for the period 1970 – 2000 was undertaken. The central theme of the study is: "How to reconcile meat quality, genetics and the consumer with bio-economic pig production in the South African pig supply chain?" A detailed analysis of the South African pig supply chain was subsequently conducted in order to add value further down the supply chain. The inherent structure of the South African pig industry was researched with the emphasis on production statistics, the pig feed industry, genetic improvement and pig information systems, slaughter houses and also slaughtering statistics. The different industry institutions, industry organisations and computer programmes in support of the South African pork supply chain were also investigated. Genetics is the hidden golden thread running through any livestock supply chain. If a substantial portion of consumer satisfaction and quality assurance can be resolved (guaranteed) at the genetic level (thus conception), these guarantees will be conducive to quality assurance further down the supply chain. Carcass and meat quality have become increasingly important in modern day pig production, despite the fact that the emphasis has been too long on input efficiency and too short on output efficiency in South Africa. This called unambiguously for the accurate estimation of genetic parameters of production and carcass traits through appropriate methodology and the right genetic technology. A high degree of accuracy will further optimize the estimation of breeding values, that of breeding objectives and also enhance the credibility of a national breeding scheme. Genetic parameters for five carcass traits were successfully estimated for the first time in the history of South African pig breeding. In future, breeding values for carcass traits, can now be determined more accurately for the Large White, Landrace and Duroc pig breeds. Extension of the present carcass evaluation analysis (Phase E of the National Pig Performance Testing Scheme) to incorporate the essential meat quality traits such as pHu, marbling, tenderness and colour into future breeding goals should eventually satisfy the consumer. In order to finally progress from an immature to a mature pig supply chain, pig producers must align themselves with value partners on both the input (raw materials) and output (end product and value added products) end of the supply chain. To embrace the concept of quality (a consumer demand principle) all levels in the production chain (at the genetic level through the breeding objectives, at the farm level through the entire production system, in transit and at the slaughterhouse and processing levels) should be integrated.Thesis (DPhil (Agricultural Economics))--University of Pretoria, 2006.Agricultural Economics, Extension and Rural Developmentunrestricte

Kriminologiese ontleding van die gebruik van forensiese kuns in die ondersteuning van slagoffers van geweldsmisdade in die Pretoria-area, Suid-Afrika

Summaries in English and AfrikaansThis research explores the potential value for the application of the visual expressionistic arts, as well as the application of forensic art for the emancipation of victims of violent crime. Qualitative research methods are used in order to make certain assumptions and recommendations for the application of the forensic arts in the emancipation of traumatized victims. The research is based on the view that human behaviour is influenced by different internal and external contextual influences. The theoretical basis for the research is further supported by the grounding principals of the psycho-analytic, symbolic interactionistic and the phenomenological theoretical approaches. The potential for the application of the forensic arts during crisis intervention and trauma counselling as a therapeutic technique and a communication medium are investigated. The potential forensic value of the victims’ art for the criminal justice system is also explored during the research.Die navorsing ondersoek die potensiele waarde vir die aanwending van die tradisionele visuele beeldende kunste asook die aanwending van die forensiese kunste vir die emansipasie van slagoffers van geweldsmisdaad. Kwalitatiewe navorsingsmetodes word tydens die navorsing gebruik ten einde sekere afleidings en aanbevelings te maak aangaande die aanwending van die forensiese kuns vir die emansipasie van getraumatiseerde misdaadslagoffers. Die navorsing word teoreties gebaseer op die beskouing van die mens wie se gedrag beinvloed word deur verskillende interne en eksterne kontekstuele invloede. Die teoretiese basis vir die navorsing word verder ondersteun deur die grondbeginsels van die psigo-analise, simboliese interaksionisme en die fenomenologiese teoretiese benaderings. Die potensiaal vir die aanwending van forensiese kuns as 'n terapeutiese tegniek en kommunikasiemedium tydens krisisingryping en berading word ondersoek. Die potensiele forensiese waarde van misdaadslagoffers se kuns in die regsplegingstelsel word ook in die navorsing ondersoek.Criminology and Security ScienceM. A. (Criminology