Formation of PCDD/Fs from the copper oxide-mediated pyrolysis and oxidation of 1,2-dichlorobenzene

Formation of polychorinated dibenzo-p-dioxins (PCDDs) has been demonstrated to occur via surface-mediated reactions of chlorinated phenols. However, polychlorinated dibenzofurans (PCDFs) are observed in much lower yields in laboratory studies than in full-scale combustors where PCDFs are in higher concentrations than PCDDs. This has led to the suggestion that at least PCDFs are formed from elemental carbon in the de novo process. However, the potential for PCDF formation from reactions of chlorinated benzenes has been largely overlooked. In this study, we investigated the potential contribution of chlorinated benzenes to formation of PCDD/Fs using 1,2-dichlorobenzene as a surrogate for reactions of other chlorinated benzenes and CuO/silica (3 wt % Cu) as a surrogate for fly ash. Results were similar for oxidative and pyrolytic conditions with a slight increase in more chlorinated products under oxidative conditions. Reaction products included chlorobenzene, polychlorinated benzenes, phenol, 2-monochlorophenol (2-MCP), dichlorophenols, and trichlorophenols with yields ranging from 0.01 to 2% for the phenols and from 0.01 to 10% for chlorinated benzenes. 4,6-Dichlorodibenzo furan (4,6-DCDF) and dibenzofuran (DF) were observed in maximum yields of 0.2% and 0.5%, respectively, under pyrolytic conditions and 0.1% and 0.3%, respectively, under oxidative conditions. In previous studies of the pyrolysis of 2-MCP under identical conditions, 4,6-DCDF and dibenzo-p-dioxin (DD) were observed with maximum yields of ～0.2% and ～0.1%, respectively, along with trace quantities of 1-monochlorodibenzo-p-dioxin (1-MCDD). Under oxidative conditions, 1-MCDD, DD, and 4,6-DCDF were observed with maximum yields of 0.3%, 0.07% and 0.1%, respectively. When combined with the fact that measured concentrations of chlorinated benzenes are 10-100× that of chlorinated phenols in full-scale combustion systems, the data suggest surface-mediated reactions of chlorinated benzenes can be a significant source of PCDD/F emissions.     

Overview of the InterPARES Trust Project in Africa: Trusting Records in an Increasingly Networked Environment

InterPARES Trust (IP Trust) research project’s goal is to generate the theoretical and methodological frameworks that address issues related to the management of digital records in networked environments. Team Africa forms part of the IP Trust project and is undertaking six case studies. This article provides an overview of the research activities within each of the case studies. Team Africa’s case studies began recently and, therefore, there are no final products of the research process. Nonetheless, ongoing dissemination activities include three conference presentations (in Croatia, Spain, and the United States) as well as eight peer-reviewed articles published. Team Africa’s case studies focus on actionable factors defined from the ground up rather than from purely theoretical constructs. One case study’s output addresses trustworthiness of records in South Africa’s public audit processes. Three case studies’ output will address the management of digital records in Botswana, Kenya, and Zimbabwe. Another case study’s output addresses the legislative and regulatory provisions related to management of records in South Africa. The last case study’s output is geared to aligning the curriculum of professionals that manage records in Africa’s institutions of higher learning.     

Optimizing soil nitrogen balance in a potato cropping system through legume intercropping

Nutrient Cycling in Agroecosystems - Negative nitrogen balance represents a major factor causing low potato yield in potato growing areas of Kenya while its excessive surplus poses a significant...     

Using Web Analytics to Assess Traffic to the Mandela Portal: The Case of African Countries

This article is a longitudinal assessment of the visitors to the Mandela Portal between 2009 and 2016. It is based on web analytics methodology that consists of a four-step process with the first and second steps using data collected by Google Analytics tool. The article outlines trends of global figures as well as specific trends within the top ten African countries. It further explored statistics from the top five African countries: South Africa, Kenya, Nigeria, Tanzania, and Ghana. There are two main findings: those related to web traffic trends and those exploring the trustworthiness of Google Analytics data.     

Enterprise Resource Planning: Past,Present, and Future

ABSTRACT

The purpose of this article is to provide a broad overview of the history and development of ERPs and outline recent developments with the advent of digital innovations like cloud computing. The research approach in this article was to review literature from both academic journals and industry reports. The article found that ERPs have changed dramatically from precursor systems like integrated control (IC) packages and material resource planning (MRP) systems. They continue to change with the advent of cloud computing, as well as digital innovations like artificial intelligence. While several articles have addressed the evolution of ERPs, this article’s unique contribution is that it covers the most recent developments, including discussions on cloud ERPs and postmodern ERPs.     

Provision of Records Created in Networked Environments in the Curricula of Institutions of Higher Learning in Africa

The importance of curriculum development on archives and records management in the digital era, especially on the African continent, cannot be overemphasized. While many universities in the global hub have included studies on all aspects of archives and records management programs with many emphasizing records created in networked environments, the same cannot be said about universities on the African continent. In Africa, education and training of archives and records professionals can be traced back several decades. Archives and records practitioners in Africa’s different countries have, over the years, taken varying paths to attain their professional qualifications. This study outlines progress on an ongoing study by InterPARES Trust Africa Team that examines the curricula in different African educational institutions and investigates the extent to which they address the increasingly complex environment that includes the management of digital records in networked environments. It is hoped that the study will inform curriculum development and review in the area of digital records at the institutions of higher learning in Africa.     

Water Allocation as a Planning Tool to Minimise Water Use Conflicts in the Upper Ewaso Ng’iro North Basin, Kenya

Inadequate water resources management and a general decline in rainfall have aggravated water scarcity problems in the Upper Ewaso Ng’iro North Basin in Kenya. Furthermore, water use conflicts in the basin have escalated in recent decades due to increased competition for available water resources. Excessive abstraction of the declining river water mainly for irrigation in the Mount Kenya and Nyandarua foot zones often leads to reduced water flow during the dry seasons, greatly affecting downstream water users. Increased water use in the basin coupled with deterioration of the vegetative cover has resulted in reduced water flows in the Ewaso Ng’iro river and its major tributaries. In addition, lack of sufficient knowledge about available water resources and current lack of coordination in water resources management in the basin often result in water deficits which have hampered development in the downstream catchment. The goal of this study was to match the water requirements of various competing sectors in the basin with the available water resources in order to attain both economic and ecological sustainability. To achieve this, GIS techniques were used to quantify the spatial and temporal stream flow. The Water Evaluation and Planning (WEAP) model was applied to evaluate water resources development based on an equilibrium scenario of the current water demand. Water use was simulated for five different sectors (domestic, livestock, wildlife, irrigation and reserve). The analyses revealed that high water demand for irrigation was the main cause of excessive water abstraction particularly in the upstream catchments, giving rise to water shortages and consequently, water use conflicts downstream. The study, therefore, recommends that rainwater harvesting be promoted in the basin in order to improve water availability for productive use.