Investigation and computer modelling of the pore structure of paper and of consolidated pigment coatings

Merged with duplicate record 10026.1/839 on 27.02.2017 by CS (TIS)The aim of this project was to enhance the current state of knowledge of the void structure of paper, and pigments used to coat paper. The porosities and pore size distributions of consolidated pigments were measured using mercury porosimetry. Prior to this work, mercury porosimetry was rarely used in this field due to problems associated with the conventional interpretation of mercury porosimetry data. These problems were examined and two limitations of mercury porosimetry were addressed. Firstly, the shrinkage of compressible samples causes an apparent increase in void volume and secondly, large void spaces shielded by smaller ones are not intruded until anomalously high applied pressures of mercury are reached. The first limitation was overcome by means of a new correction procedure which, uniquely, also allows the measurement of the bulk modulus of the continuous solid phase of a porous sample. Shielding effects have been taken into account by means of a software package known as Pore-Cor, which generates a three dimensional structure which has both a mercury intrusion curve and porosity in close agreement with experiment. It has also been possible to calculate the permeabilities and tortuosity of the simulated structure and this provides realistic and useful values, which may not be measured experimentally. Mercury porosimetry and a range of specialised absorption techniques, including liquid porosimetry, were used to characterise the porous structures of a highly filled paper which had been calendered using a range of different conditions. A unique feature of this work is that for the first time it has been shown that two porosimetric techniques which measure overlapping pore size distributions may be combined to give a better indication of the total pore size distribution.ECC International plc

Groundwater Depletion and Agricultural Land Use Change in Wichita County, Kansas

Though researchers have documented groundwater and land use changes in the High Plains, few studies have investigated their interactions. This paper examines the relationship between groundwater depletion and agricultural land use change in greater detail than previous studies. Water well measurements and satellite imagery were used to detect changes in groundwater and land cover in Wichita County, Kansas, between 1975 and 2001. Analysis of these changes using GIS indicated that areas experiencing the greatest decline in groundwater were indeed being removed from irrigation, while areas with limited groundwater decline were experiencing fewer land use changes

Optimization of a continuous hot embossing process for fabrication of micropyramid structures in thermoplastic sheets

Reported is the manufacture and optimization of inverted micropyramid cavity structures into thermoplastic sheets using roll-to-roll (R2R) embossing. To manufacture the master, an ultraprecision diamond machining method was applied to create seamless surface structures into a copper-coated hot embossing roller. Using the hot embossing process, the roller features were successfully transferred to 2 mm thick polymethyl methacrylate (PMMA) sheets. Optimization of the R2R control process variables was conducted using Taguchi's numerical methods, which showed the importance of the roller temperature for a successful pattern transfer. The work presents a novel fabrication technique that allows microstructures to be manufactured into thick PMMA sheets in a continuous process

5th International Conference on Future-Oriented Technology Analysis (FTA) - Engage today to shape tomorrow

The practice-oriented paper reflects on the results of a strategic technology roadmapping project realised in the Green Triangle region of South Australia. The project integrated different methods in order to provide policy recommendations for the renewal of the forest industry in the region. Firstly, the project created a multi-criteria assessment framework for the evaluation of the present state of local companies. Secondly, the project made three value chain depictions: one that described the present value chain based on physical, monetary and information flows, and two so-called ‘potential’ value chain descriptions. Thirdly, the projectformulated technology roadmaps and assessed the potential for forest industry renewal. Fourthly, the project provided detailed policy recommendations based on the findings in the project.The integrated methodological approach of the project provided a robust basis for construction of policy recommendations. The company assessment grouped the local companies in four categories for comparative assessment purposes: forest owners, harvesters and hauliers, sawmills, and specialised suppliers. For the roadmap construction, the main information categories were drivers, markets, regulation, customer needs, solutions, and enabling technologies, and the specific dynamics connected to all these categories. This information was structured into three temporal spans: present, short term (ca. 3-5 years)and long term (ca. 5-10 years).There are, at least, three novel aspects of the project. Firstly, the integration of multi-criteria evaluation, value chain analysis and roadmapping creates new opportunities, but also new challenges. Secondly, the future-oriented view of the Australian forest industry is a new aspect. Thirdly, the project also had a strong regional policy perspective, especially connected with the discussions on path dependency and path creation in the regional development context.The project had both practical and managerial implications. Firstly, the company assessment identified the domains where each individual firm had weaknesses as well as where the group as a whole lagged global best practice. Secondly, the value chain analysis showed strengths and weaknesses of the present structure, but also delineated the necessary components to be developed in order to move towards higher value added production. Thirdly, the roadmaps showed the frontiers of research and business in advanced cellulose fibre-based industries, and made possible the positioning of the Green Triangle region.The project had two wider implications for policy. Firstly, the integrated methodological approach of the foresight exercise enabled the production of detailed policy recommendations that were embedded in the local industrial context. Secondly, the project open a window of opportunity to consider so-called platform policies, that is, policies that aim to develop the fragmented regional structure of the Green Triangle’s forest industry towards an integrated cluster-based platform, which would enable the region to benefit from agglomeration economics through a collaborative strategy.</p

Modeling dimethylsulphide production in the upper ocean

Dimethylsulphide (DMS) is produced by upper ocean ecosystems and emitted to the atmosphere, where it may have an important role in climate regulation. Several attempts to quantify the role of DMS in climate change have been undertaken in modeling studies. We examine a model of biogenic DMS production and describe its endogenous dynamics and sensitivities. We extend the model to develop a one-dimensional version that more accurately resolves the important processes of the mixed layer in determining the ecosystem dynamics. Comparisons of the results of the one-dimensional model with an empirical relationship that describes the global distribution of DMS, and also with vertical profiles of DMS in the upper ocean measured at the Bermuda Atlantic Time Series, suggest that the model represents the interaction between the biological and physical processes well on local and global scales. Our analysis of the model confirms its veracity and provides insights into the important processes determining DMS concentration in the oceans

Dimethylsulphide, clouds, and phytoplankton: Insights from a simple plankton ecosystem feedback model

The hypothesis that marine plankton ecosystems may effectively regulate climate by the production of dimethylsulphide (DMS) has attracted substantial research effort over recent years. This hypothesis suggests that DMS produced by marine ecosystems can affect cloud properties and hence the averaged irradiance experienced by the phytoplankton that produce DMS’s precursor dimethylsulphoniopropionate (DMSP). This paper describes the use of a simple model to examine the effects of such a biogenic feedback on the ecosystem that initiates it. We compare the responses to perturbation of a simple marine nitrogen-phytoplankton-zooplankton (NPZ) ecosystem model with and without biogenic feedback. Our analysis of this heuristic model reveals that the addition of the feedback can increase the model’s resilience to perturbation and hence stabilize the model ecosystem. This result suggests the hypothesis that DMS may play a role in stabilizing marine plankton ecosystem dynamics through its effect on the atmosphere

Fluxes and gas transfer rates of the biogenic trace gas DMS derived from atmospheric gradients

Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 109 (2004): C08S10, doi:10.1029/2003JC001795.Gas transfer rates were determined from vertical profile measurements of atmospheric dimethylsulfide (DMS) gradients over the equatorial Pacific Ocean obtained during the GasEx-2001 cruise. A quadratic relationship between gas transfer velocity and wind speed was derived from the DMS flux measurements; this relationship was in close agreement with a parameterization derived from relaxed eddy accumulation measurements of DMS over the northeastern Pacific Ocean. However, the GasEx-2001 relationship results in gas transfer rates that are a factor 2 higher than gas transfer rates calculated from a parameterization that is based on coincident eddy correlation measurements of CO2 flux. The measurement precision of both the profiling and eddy correlation techniques applied during GasEx-2001 is comparable; the two gas transfer data sets are in agreement within their uncertainty. Differences in the number of samples and the wind speed range over which CO2 and DMS fluxes were measured are likely causes for the observed discrepancy.Funding for this work came from the Netherlands Organization for Scientific Research (NWO) and from the NOP project 951203: ‘‘Micrometeorology of air/sea fluxes of carbon dioxide. This work was supported by the Global Carbon Cycle project of the NOAA Office of Global Programs grant NA17RJ1223, National Science Foundation grant OCE-9986724, and NSF grant ATM-0120569

A gamma-lactamase from cereal infecting Fusarium spp. catalyses the first step in the degradation of the benzoxazolinone class of phytoalexins

The benzoxazolinone class of phytoalexins are released by wheat, maize, rye and other agriculturally important species in the Poaceae family upon pathogen attack. Benzoxazolinones show antimicrobial effects on plant pathogens, but certain fungi have evolved mechanisms to actively detoxify these compounds which may contribute to the virulence of the pathogens. In many Fusarium spp. a cluster of genes is thought to be involved in the detoxification of benzoxazolinones. However, only one enzyme encoded in the cluster has been unequivocally assigned a role in this process. The first step in the detoxification of benzoxazolinones in Fusarium spp. involves the hydrolysis of a cyclic ester bond. This reaction is encoded by the FDB1 locus in F. verticillioides but the underlying gene is yet to be cloned. We previously proposed that FDB1 encodes a γ-lactamase, and here direct evidence for this is presented. Expression analyses in the important wheat pathogen F. pseudograminearum demonstrated that amongst the three predicted γ-lactamase genes only the one designated as FDB1, part of the proposed benzoxazolinone cluster in F. pseudograminearum, was strongly responsive to exogenous benzoxazolinone application. Analysis of independent F. pseudograminearum and F. graminearum FDB1 gene deletion mutants, as well as biochemical assays, demonstrated that the γ-lactamase enzyme, encoded by FDB1, catalyses the first step in detoxification of benzoxazolinones. Overall, our results support the notion that Fusarium pathogens that cause crown rot and head blight on wheat have adopted strategies to overcome host-derived chemical defences