Effect of Fiber Surface Treatments on Thermo-Mechanical Behavior of Poly(Lactic Acid)/Phormium Tenax Composites

In the present study, Phormium Tenax fiber reinforced PLA composites were processed by injection molding and twin screw compounding with a fiber content ranging from 10 to 30 wt%. Three surface treatment methods have been used to improve the Phormium Tenax fiber-matrix interfacial bonding that are as follows: (1) aqueous alkaline solution, (2) silane coupling agent, and (3) a combination of alkaline and silane treatment. The mechanical, thermal and morphological properties of the resulting composites were investigated. The results have shown that the moduli of surface treated fiber reinforced composites are lower than the ones obtained for untreated composites (as a consequence of the decrease in fiber modulus caused by the chemical treatments) and no significant increase in strength was observed for any of the composites compared to neat PLA. SEM micrographs of composite fractured surfaces confirmed an improvement in the interfacial strength, which was insufficient nonetheless to significantly enhance the mechanical behavior of the resulting composites. Results from thermogravimetric analysis and differential scanning calorimetry suggest that surface treatment of Phormium affects the ability of PLA to cold crystallize, and the thermal stability of the composites at the different fiber contents was reduced with introduction of alkali and silane treated Phormium fibers.     

Disaster risk reduction in developing countries: costs, benefits and institutions

Some 60,000 people worldwide die annually in natural disasters, mostly due to the collapse of buildings in earthquakes, and primarily in the developing world. This is despite the fact that engineering solutions exist that can eliminate almost completely the risk of such deaths. Why is this? The solutions are expensive and technically demanding, so their cost–benefit ratio often is unfavourable as compared to other interventions. Nonetheless, there are various public disaster risk reduction interventions that are highly cost‐effective. That such interventions frequently remain unimplemented or ineffectively executed points to a role for issues of political economy. Building regulations in developing countries appear to have limited impact in many cases, perhaps because of inadequate capacity and corruption. Public construction often is of low quality, perhaps for similar reasons. This suggests the need for approaches that emphasise simple and limited disaster risk regulation covering only the most at‐risk structures—and that, preferably, non‐experts can monitor—as well as numerous transparency and oversight mechanisms for public construction projects.     

Immunological methods for food web analysis in a soft-bottom benthic community

Basic to nearly any prediction concerning the behavior and structure of entire communities or of their components is knowledge of trophic connections among species. A major impediment to such understanding of soft-bottom benthos is methodological. Because none of the routinely available methods of food web analysis (e.g. visual gut content analysis, direct observation of feeding, tracer techniques) is generally suitable for examining all trophic interactions of benthic infauna, we rought to evaluate the potential of immunological methods for identifying predatorprey relationships in one typical, estuarine, intertidal sand flat. Whole-organism extracts of individual macro- and meiofaunal taxa were injected into rabbits to produce antisera of varying specificity. Double immunodiffusion precipitin tests of antiserum specificity revealed both phyletic and trophic relationships among 20 taxa. Using relatively unspecific antisera, preliminary analysis of the stomach contents of a few surface deposit-feeders and particle browsers was successful, giving positive identification of several trophic links which would otherwise have gone undetected. The production of taxon-specific antisera is expected to provide the methodological tool necessary to document the breadth of trophic connections in a marine benthic food web.     

Climate variations and New Zealand agriculture: the CLIMPACTS system and issues of spatial and temporal scale.

Internationally and nationally, New Zealand has a growing requirement to assess and report on the possible effects of climate change. In association with this requirement, the science of climate change is rapidly evolving requiring a capacity for rapid reassessment of effects to take account of scientific advances. Consequently, past assessment methods, which have not been computationally efficient, nor easily repeated, are becoming outdated. To address this gap, an integrated assessment model (IAM), the CLIMPACTS system, has been developed for New Zealand. The CLIMPACTS system has been developed to provide flexibility in application, to be easily updated to take account of scientific advances, and capable of providing information in a manner that is relevant to policymakers. In order to be relevant in New Zealand, it has been necessary to account for different scales of assessment, nationally, at specific sites, and regionally. Nationally, the focus is on spatial applications (e.g., changes in areas of suitability), whereas at sites, the focus is on temporal applications (e.g., changes in risk). The regional capacity in the CLIMPACTS system has required an integration of spatial and temporal applications. This paper describes briefly the capability that has been developed at these different scales of assessment, with brief examples for each. The CLIMPACTS system has enhanced New Zealand's capability to examine environmental sensitivities to climate change, as a basis for better informed policy decisions. Importantly, it is an evolving platform that can be readily extended to other sectors and updated, for example, to account for the effects of internationally agreed greenhouse gas (GHG) emission targets.     

Life Cycle Analysis of Extruded Films Based on Poly(lactic acid)/Cellulose Nanocrystal/Limonene: A Comparative Study with ATBC Plasticized PLA/OMMT Systems

Life cycle analysis (LCA) of limonene plasticized poly(lactic acid) (PLA) films containing cellulose nanocrystals (CNC) extracted, by acid hydrolysis, from Phormium tenax leaf fibres, was assessed and compared with the results of acetyl tributyl citrate (ATBC) plasticized PLA films, having equivalent mechanical properties, containing organo-modified montmorillonite (OMMT). Eco-Indicator 99 tool has been adopted as the main method for life cycle assessment. Results indicated that, despite CNC are biobased fillers obtained by natural sources, the related chemical extraction leads to a large environmental footprint and a relatively relevant energy expense. LCA characterization of these films demonstrated that the environmental impact of PLA/limonene film reinforced with 1% in weight of CNC (PLA/CNC/limonene) is comparable to the environmental impact of polylactic acid films reinforced with OMMT and plasticized with a petroleum based plasticizer (ATBC) (PLA/OMTT/ATBC). A “cradle to gate” approach has been considered for both the film typologies.     

Mass Burn Incineration with a Presorted MSW Fuel

This research, supported by the U.S. Dept. of Energy, investigates potential benefits to mass burn incineration from burning a presorted MSW fuel. Comparative boiler efficiency tests at three mass burn incineration sites utilizing as-received MSW and a presorted MSW fuel are reported. Test results indicate that waste presorting can provide substantial benefits to the mass burn process. Flue gas and ash heavy metals are found to be significantly reduced. Discarded automobile batteries are found to substantially contribute to lead levels in the waste stream. Reductions in emissions of CO, HC, HC1, HF, and NO_X are reported. Increases in facility boiler efficiency and MSW disposal capacity are measured.     

Benchmark calculations from summarized data: an example

Benchmark calculations often are made from data extracted from publications. Such data may not be in a form most appropriate for benchmark analysis, and, as a result, suboptimal and/or non-standard benchmark analyses are often applied. This problem can be mitigated in some cases using Monte Carlo computational methods that allow the likelihood of the published data to be calculated while still using an appropriate benchmark dose (BMD) definition. Such an approach is illustrated herein using data from a study of workers exposed to styrene, in which a hybrid BMD calculation is implemented from dose response data reported only as means and standard deviations of ratios of scores on neuropsychological tests from exposed subjects to corresponding scores from matched controls. The likelihood of the data is computed using a combination of analytic and Monte Carlo integration methods.

The release of nitrous oxide from the intertidal zones of two European estuaries in response to increased ammonium and nitrate loading

Nitrous oxide (N₂O) release and denitrification rates were investigated from the intertidal saltmarsh and mudflats of two European river estuaries, the Couesnon in Normandy, France and the Torridge in Devon, UK. Sediment cores and water were collected from each study site and incubated for 72 h in tidal simulation chambers. Gas samples were collected at 6 and 12 h intervals from the chambers during incubation. From these N₂O emission rates were calculated. The greatest rates for both N₂O production and denitrification were measured from saltmarsh cores. These were 1032 μmol N₂O m^?2 day^?1 and 2518 μmol N₂ m^?2 day^?1, respectively, from the Couesnon and 109 μmol N₂O m^?2 day^?1 and 303 μmol N₂ m^?2 day^?1 from the Torridge. A strong positive correlation was apparent with N₂O emission rates and ammonium concentration in the sediment, nitrate concentration in floodwater and sediment aerobicity.     

Place attachment and place identity: First-year undergraduates making the transition from home to university

This paper examines the issues emanating from the transition into a new social and cultural environment distant from the home, the context of which is provided by the transition from home to university. The study analyses the transitional process over a period of 5 months, using data obtained from in-depth semi-structured interviews and participant observation of ten first-year undergraduates who moved to study at the University of Gloucestershire in Cheltenham. It explores the mediating variables that impact place attachment and place identity during the transition from home to university. Within this context consideration is given to how participants made sense of changes in their socio-spatial environment, the ensuing problems and challenges of doing so, and how these meanings affected self-perceptions and self-evaluations. The analysis demonstrates how participant's stories of the transition evince an abiding concern with the loss of place, manifest in terms of an erosion of a sense of belonging, attachment and continuity and an undermining of home's capacity to symbolise the self. The implications of such accounts for our understanding of place attachment and identity are then explored. The paper concludes by advocating a holistic approach to our conceptualisation of place, given that place meanings are constantly being evaluated and redefined in light of changing social and physical relationships with place and between people and place.