Properties and applications of composite diamond coatings

A wear resistant coating consisting of micron size particles of shock-synthesized diamond uniformly dispersed in a plated metal matrix has been developed. The composite coating process is described and the controlling parameters are discussed. Laboratory and field tests have demonstrated that the coatings have excellent wear resistance and are suitable for many industrial applications as a replacement for conventional wear resistant materials particularly for combating low to medium pressure abrasive and adhesive wear.     

Primary beneficiation of tantalite using magnetic separation and acid leaching

Primary beneficiation was successfully performed prior to dissolution of manganotantalite （sample A） and ferrotantalite （sample C） samples obtained from two different mines in the Naquissupa area, Mozambique. Magnetic separation removed the majority of iron and titanium, whereas H2SO4 leaching removed a large portion of thorium and uranium in these samples. Analytical results indicated that 64.14wt% and 72.04wt% of the total Fe and Ti, respectively, and -2wt% each of Nb205 and Ta205 were removed from sample C （ferrotantalite） using the magnetic separation method, whereas only 9.64wt% and 8.66wt% of total Fe203 and TiO2, respectively, and -2wt% each of NbEOs and Ta2O5 were removed from sample A （manganotantalite）. A temperature of 50℃ and a leaching time of 3 h in the presence of concentrated HESOa were observed to be the most appropriate leaching conditions for removal of radioactive elements from the tantalite ores. The results obtained for sample A under these conditions indicated that 64.14wt% U3O8 and 60.77wt% ThO2 were leached into the acidic solution, along with 4.45wt% and 0.99wt% of Nb2O5 and Ta2O5, respectively.     

Durability of CFRP cables exposed to simulated concrete environments

One of the main causes of structural deficiency in concrete bridges is the deterioration of the constituent materials. Some transportation agencies have started exploring the use of carbon fiber reinforced polymers (CFRP) as a corrosion-resistant alternative to steel prestressing materials for longer lasting concrete bridge structures. To implement CFRP in prestressed concrete bridge structures with more confidence, an understanding of the challenges pertaining to durability under in-service environmental conditions is essential. This paper explores the effects of temperature with alkaline and alkaline/chloride solutions on material properties over time, in the context of reinforced and prestressed concrete structures for transportation applications. The durability testing yielded several key findings: (1) higher temperatures accelerate degradation, (2) moisture sorption was the primary process responsible for the observed degradation, with plasticization and microcracking as the controlling mechanisms leading to fiber–matrix interfacial debonding, and (3) a relaxation-based analytical model was implemented to predict residual properties after environmental exposure, showing promising agreement with experimental data.     

‘Day Labour’ and ‘Xenophobia’ in South Africa: the Need for Mixed Methods Approaches in Policy-Orientated Research

Much policy-orientated research in South Africa relies solely on large-scale surveys. Little or no case study research is undertaken as part of studies despite broad international acknowledgement of the benefits of mixing methods. In the South African poverty and demographic literature, strong arguments have been made for the incorporation of case study approaches to arrive at a deeper and more accurate understanding of social phenomena. This paper, which draws on an ethnographic study of ‘day labourers’ (both South African and foreign) in Cape Town, together with an extensive range of relevant literature, extends this line of argument to research on casual employment and relations between South Africans and foreign nationals. It highlights a number of questionable assumptions and superficial analyses present in previous survey-based research on these topics. It also discusses the potential contribution of more case study work and some of the practical issues associated with linking methodologies in development research.     

A randomized double‐blind crossover study of indoor air filtration and acute changes in cardiorespiratory health in a First Nations community

Few studies have examined indoor air quality in First Nations communities and its impact on cardiorespiratory health. To address this need, we conducted a crossover study on a First Nations reserve in Manitoba, Canada, including 37 residents in 20 homes. Each home received an electrostatic air filter and a placebo filter for 1 week in random order, and lung function, blood pressure, and endothelial function measures were collected at the beginning and end of each week. Indoor air pollutants were monitored throughout the study period. Indoor PM_2.5 decreased substantially during air filter weeks relative to placebo (mean difference: 37 μg/m³, 95% CI: 10, 64) but remained approximately five times greater than outdoor concentrations owing to a high prevalence of indoor smoking. On average, air filter use was associated with a 217‐ml (95% CI: 23, 410) increase in forced expiratory volume in 1 s, a 7.9‐mm Hg (95% CI: ?17, 0.82) decrease in systolic blood pressure, and a 4.5‐mm Hg (95% CI: ?11, 2.4) decrease in diastolic blood pressure. Consistent inverse associations were also observed between indoor PM_2.5 and lung function. In general, our findings suggest that reducing indoor PM_2.5 may contribute to improved lung function in First Nations communities.     

Analysis of Phenolic Composition of Noble Muscadine (Vitis rotundifolia) by HPLC‐MS and the Relationship to Its Antioxidant Capacity

Abstract: Phenolic compounds and anthocyanins in muscadines have attracted much attention due to their diverse biological activities. With bioassays of antioxidant activities in terms of total phenolic content (TPC), total anthocyanin content (TAC), total procyanidin content (TPA), oxygen radical absorbance capacity (ORAC), and ferric reducing antioxidant power (FRAP) of different parts of the Noble muscadine, the butanol (BuOH) extract of the muscadine skin showed the highest TPC (317.91 ± 1.83 mg GAE/100 g FW), which might be ascribed to its high TAC of 227.06 ± 1.29 mg/100 g fresh weight (FW). The ethyl acetate (EtOAc) extract of the muscadine seed contained the highest TPA (55.30 ± 0.63 mg CE/100 g FW). Correlation analyses demonstrated a significant linear relationship of TPC and TAC compared to their ORAC and FRAP values within the range of R² from 0.9283 to 0.9936, which suggested that phenolics and anthocyanins in the extracts contributed significantly to their antioxidant potential. Nineteen individual phenolics and 5 anthocyanins were identified by HPLC‐MS, which indicated different chemical profiles of anthocyanins and other phenolics in the muscadine extracts. Practical Application: The paper has provided rich information of bioactive phytochemical profiles in different solvent extracts and their correlation with the antioxidant activity in the muscadine that is a very special regional fruit in U.S. Its high content of phenolic compounds demonstrates that muscadine could be beneficial to human health.     

Phage‐mediated transfer of virulence genes

Bacteriophages as accessory genetic elements play a crucial role in the dissemination of genes and the promotion of genetic diversity within bacterial populations. Such horizontal transfer of DNA is critical in the emergence of new pathogenic organisms, through the dissemination of genes encoding virulence factors such as toxins, adhesins and agressins. Phages can transfer genes that are not necessary for bacteriophage persistence and are generally recognised by their ability to convert their host bacteria to new phenotypes. This phenomenon is known as phage conversion. If such converting genes encode for virulence factors, the consequences of phage infection may include increased virulence of the host bacteria, and the conversion of a non‐pathogenic strain to a potentially dangerous pathogen. A number of virulence factors in bacteria causing diseases in plants, animals and humans are encoded by converting phages, the vast majority of which are temperate as opposed to lytic in nature. © 2001 Society of Chemical Industry     

The Relation Between Television Exposure and Theory of Mind Among Preschoolers

This study explored the relation between preschoolers' television exposure and one important indicator of cognitive processing called theory of mind (ToM). A total of 107 preschoolers and their parents provided data on the preschoolers' television exposure (including both intentional viewing and exposure via background television), parent–child discussion of television, and preschoolers' ToM. The results indicated that preschoolers who were exposed to more background television and who had a television in their bedroom performed more poorly on ToM assessments compared with other children. Parent–child discussion of television was positively related to ToM performance, however. These results have implications for how we understand the effects of television on preschoolers.