Microstructural analysis of surface and interface zones in concrete

Several of OPC paste and concrete specimens, with different mix proportions, were cast against CPF and impermeable formwork (IF) and the profiles of pore structure, microhardness and scratch hardness of the cover zone were established. The chloride ingress and the depth of carbonation of the surface zone of concrete cast against CPF and IF were investigated. The main mechanisms controlling the ECR processes and the factors affecting such treatment were critically reviewed. Subsequently, as a means of restoring passivation of steel embedded in carbonated concrete, such HCP specimens were subjected to ECR. The influence of ECR on the chemistry of the pore solution and the microstructure of the surface and the steel/cement past interface zones were also studied. The main findings of this investigation were as follows: (a) The thickness of the microstructure gradient of cover concrete is significantly decreased with increasing period of water curing but is relatively unaffected by curing temperature, w/e ratio and the use of cement replacement materials. (b) The scratch hardness technique was shown to be potentially useful for characterising the microstructure and microhardness gradients of the surface zone. (c) A relationship between the microstructure gradient and mass transport properties of the surface zone was established. (d) The use of CPF resulted in a significant reduction in porosity of both the cement paste matrix and the aggregate/cement paste transition zone, and a marked improvement in the resistance of the surface zone to carbonation and the ingress of chloride ions. (e) The ECR treatment resulted in a marked densification of the pore structure and in changes to the pore solution chemistry and the cement phases of near-surface and steel/cement paste transition zones. This effect was more pronounced with current density, period of treatment and particularly with the use of sodium phosphate as an electrolyte.

Medicines optimisation for young people with juvenile arthritis and other long-term conditions:system-level barriers to engagement

To explore the views of pharmacy and rheumatology stakeholders about system-related barriers to medicines optimisation activities with young people with long-term conditions. A three-phase consensus-building study comprising (1) focus groups with community and hospital pharmacists; (2) semi-structured telephone interviews with lay and professional adolescent rheumatology stakeholders and pharmacy policymakers, and (3) multidisciplinary discussion groups with community and hospital pharmacists and rheumatology staff. Qualitative verbatim transcripts from phases 1 and 2 were subjected to framework analysis. Themes from phase 1 underpinned a briefing for phase 2 interviewees. Themes from phases 1 and 2 generated elements of good pharmacy practice and current/future pharmacy roles for ranking in phase 3. Results from phase 3 prioritisation and ranking exercises were captured on self-completion data collection forms, entered into an Excel spreadsheet and subjected to descriptive statistical analysis. Institutional ethical approval was given by Aston University Health and Life Sciences Research Ethics Committee. Four focus groups were conducted with 18 pharmacists across England, Scotland and Wales (7 hospital, 10 community and 1 community/public health). Fifteen stakeholders took part in telephone interviews (3 pharmacist commissioners; 2 pharmacist policymakers; 2 pharmacy staff members (1 community and 1 hospital); 4 rheumatologists; 1 specialist nurse, and 3 lay juvenile arthritis advocates). Twenty-five participants took part in three discussion groups in adolescent rheumatology centres across England and Scotland (9 community pharmacists; 4 hospital pharmacists; 6 rheumatologists; 5 specialist nurses, and 1 physiotherapist). In all phases of the study, system-level issues were acknowledged as barriers to more engagement with young people and families. Community pharmacists in the focus groups reported that opportunities for engaging with young people were low if parents collected prescriptions alone, which was agreed by other stakeholders. Moreover, institutional/company prescription collection policies – an activity largely disallowed for a young person under 16 without an accompanying parent - were identified by hospital and community pharmacists as barriers to open discussion and engagement. Few community pharmacists reported using Medicines Use Review (England/Wales) or Chronic Medication Service (Scotland) as a medicines optimisation activity with young people; many were unsure about consent procedures. Despite these limitations, rheumatology stakeholders ranked highly the potential of pharmacists empowering young people with general health care skills, such as repeat prescription ordering. The pharmacy profession lacks vision for its role in the care of young people with long-term conditions. Pharmacists and rheumatology stakeholders identified system-level barriers to more engagement with young people who take medicines regularly. We acknowledge that the modest number of participants may have had a specific interest and thus bias for the topic, but this underscores their frank admission of the challenges. Professional guidance and policy, practice frameworks and institutional/company policies must promote flexibility for pharmacy staff to recognise and empower young people who are able to give consent and take responsibility for medicines activities. This will increase mutual confidence and trust, and foster pharmacy’s role in teaching general health care skills. In this way, pharmacists will be able to build long-term relationships with young people and families.

Shell-side transfer in shell-and-tube heat exchangers

Local mass transfer coefficients were determined by using the electrochemical technique. A simple model of a heat exchanger with segmental nickel tube joined to p.v.c. rods replaced the exchanger tubes. Measurements were made for both no-Ieakage, semi-leakage and total leakage configurations. Baffle-spacings of 47.6 mm, 66.6 mm, 97 mm and 149.2 mm wer studied. Also studied were the overall exchanger pressure drops for each configuration. The comparison of the heat transfer data with this work showed good agreement at high flow rates for the no-leakage case, but the agreement became poor for lower flow rates and leakage configurations. This disagreement was explained by non-analogous driving forces existing in the two systems. The no-leakage data showed length-wise variation of transfer coefficients along the exchanger length. The end compartments showing transfer coefficients inferior by up to 26% compared to tbe internal compartments, depending on Reynolds number. With the introduction of leakage streams this variation however became smaller than the experimental accuracy. A model is outlined to show the characteristic behaviour of individual electrode segments within the compartment. This was able to discriminate between cross and window zones for the no- leakage case, but no such distinction could be made for the leakage case. A flow area was found which, when incorporated in the Reynolds number, enabled the correlation of baffle-cut and baffle-spacing parameters for the no-leakage case . This area is the free flow area determined at the baffle edge. Addition of the leakage area to this flow area resulted in correlation of all commercial leakage geometrical parameters. The procedures used to correlate the pressure drop data from a total of eighteen different configurations on a single curve are also outlined.

Parallel geostatistics for sparse and dense datasets

Very large spatially-referenced datasets, for example, those derived from satellite-based sensors which sample across the globe or large monitoring networks of individual sensors, are becoming increasingly common and more widely available for use in environmental decision making. In large or dense sensor networks, huge quantities of data can be collected over small time periods. In many applications the generation of maps, or predictions at specific locations, from the data in (near) real-time is crucial. Geostatistical operations such as interpolation are vital in this map-generation process and in emergency situations, the resulting predictions need to be available almost instantly, so that decision makers can make informed decisions and define risk and evacuation zones. It is also helpful when analysing data in less time critical applications, for example when interacting directly with the data for exploratory analysis, that the algorithms are responsive within a reasonable time frame. Performing geostatistical analysis on such large spatial datasets can present a number of problems, particularly in the case where maximum likelihood. Although the storage requirements only scale linearly with the number of observations in the dataset, the computational complexity in terms of memory and speed, scale quadratically and cubically respectively. Most modern commodity hardware has at least 2 processor cores if not more. Other mechanisms for allowing parallel computation such as Grid based systems are also becoming increasingly commonly available. However, currently there seems to be little interest in exploiting this extra processing power within the context of geostatistics. In this paper we review the existing parallel approaches for geostatistics. By recognising that diffeerent natural parallelisms exist and can be exploited depending on whether the dataset is sparsely or densely sampled with respect to the range of variation, we introduce two contrasting novel implementations of parallel algorithms based on approximating the data likelihood extending the methods of Vecchia [1988] and Tresp [2000]. Using parallel maximum likelihood variogram estimation and parallel prediction algorithms we show that computational time can be significantly reduced. We demonstrate this with both sparsely sampled data and densely sampled data on a variety of architectures ranging from the common dual core processor, found in many modern desktop computers, to large multi-node super computers. To highlight the strengths and weaknesses of the diffeerent methods we employ synthetic data sets and go on to show how the methods allow maximum likelihood based inference on the exhaustive Walker Lake data set.

The relationship between the spatial pattern of senile plaques and neurofibrillary tangles in Alzheimer's disease

The topographic pattern of senile plaques (SP) and neurofibrillary tangles (NFT) was studied in silver stained coronal sections of neocortex and hippocampus in ten cases of Alzheimer's disease (AD). Both lesions showed evidence of clustering in the tissue with many of the clusters being regularly spaced. The patterns of SP and NFT were compared 1) in the same cortical zone, 2) between upper and lower zones of the cortex and 3) in regions connected by either association fibres or the perforant path. Correlations between the lesions in the same cortical zone were found in 20% of the layers examined while correlations between upper and lower zones occurred in 64% of cortical regions examined. There was evidence that NFT in upper and lower cortex may be in register in some tissues. In addition, positive correlations were found between upper NFT and lower SP and negative correlations between upper SP and lower NFT in some tissues. Regular clustering of lesions was also observed in brain regions connected to one another suggesting that they develop on functinally related sets of neurons.

The diagenesis and palaeomagnetism of permian and triassic sediments from central Spain

Detailed diagenetic and palaeomagnetic studies have been made of Permian and Triassic rocks from the Iberian Cordillera, Spain. Five stratigraphical units comprising the Autunian, Saxonian, Buntsandstein, Muschelkalk, and Keuper have been studied in a number of sections which have been well documented sedimentologically. Autuninan rocks have a characteristic remanence which is exclusively reversed and corresponds to the Kiaman Interval. The pole position identified is consistent with previous studies, which indicate the rotation of Iberia in post-Triassic times. The Saxonian facies show complex multicomponent magnetizations; no polarity zonation can be resolved. The Buntsandstein is remarkable in that much of it is remagnetised in a direction similar to the present-day local geomagnetic field direction. The secondary remanence is carried by fine-grained haematite which has been formed as a result of carbonate dissolution associated with structural inversion of the Iberian Cordillera. Dating of diagenetic events associated with this remagnetization is also possible. Fragments of primary remanence are preserved in some fine-grained lithologies of the Buntsandstein. These indicate that normal and reversed zones of magnetization were originally present. The magnetization of the Muschelkalk and Keuper carbonates is also complex; secondary components similar to those of the Buntsandstein are present but there is evidence that primary components were predominantly normal during Karnian times.

Sofia’s story in translation. Leaving Shanghai:translation and commentary

The article analyzes the French short story "Sofia's Story. Leaving Shanghai," by Isabelle Charpentier. The characters and plot are explored. It discusses the author's unique writing style which is the use of long and detailed lists that appear at interval's throughout. It presents the story's translation in English language. Also cited is a list of a different sort towards the end that encapsulates the juxtaposition and contrast that centers on Sofia's experiences.

Sofia’s story in translation. Leaving Shanghai:translation and commentary

The article analyzes the French short story "Sofia's Story. Leaving Shanghai," by Isabelle Charpentier. The characters and plot are explored. It discusses the author's unique writing style which is the use of long and detailed lists that appear at interval's throughout. It presents the story's translation in English language. Also cited is a list of a different sort towards the end that encapsulates the juxtaposition and contrast that centers on Sofia's experiences.