Monitoring the moisture transport in building stones using fibre optic relative humidity sensors

Weathering of stone is one of the major reasons for the damage of stone masonry structures and it takes place due to interlinked chemical, physical and biological processes in stones. The key parameters involved in the deterioration processes are temperature, moisture and salt. It is now known that the sudden variations in temperature and moisture greatly accelerate the weathering process of the building stone fabric. Therefore, in order to monitor these sudden variations an effective and continuous monitoring system is needed. Furthermore, it must consist of robust sensors which are accurate and can survive in the harsh environments experienced in and around masonry structures. Although salt penetration is important for the rate of deterioration of stone masonry structures, the processes involved are much slower than the damage associated with temperature and moisture variations. Therefore, in this paper a novel fibre optic temperature cum relative humidity sensor is described and its applicability in monitoring building stones demonstrated. The performance of the sensor is assessed in an experiment comprising wetting and drying of limestone blocks. The results indicate that the novel fibre optic relative humidity sensor which is tailor made for applications in masonry structures performed well in wetting and drying tests, whilst commercial capacitance based sensors failed to recover during the drying regime for a long period after a wetting regime. That is, the fibre optic sensor has the capability to measure both sorption and de-sorption characteristics of stone blocks. This sensor is used in a test wall in Oxford and the data thus obtained strengthened the laboratory observations.

Study of reliability of fibre Bragg grating fibre optic strain sensors for field-test applications

In this paper, the reliability and thus the suitability of optical fibre strain sensors for surface strain measurement in concrete structures was investigated. Two different configurations of optical strain sensors were used each having different mountings making them suitable for different uses in various structures. Due to the very limited time available to install the sensors and take result, commercially packaged sensors were used. In the tests carried out each sensor was mounted onto a concrete beam which was then subjected to a range of known and calibrated loadings. The performance of the optical strain sensors thus evaluated was compared with the results of conventional techniques. This comparison allows for selecting the best performing combination of sensor/mounting, i.e. long-gauge sensor with mounts bolted to threaded rods glued into the concrete for use in future work in a field test where a limited time window was available for installation, testing and post-test demounting. © 2012 Elsevier B.V.

Chronic constipation in long stay elderly patients:a comparison of lactulose and a senna-fibre combination

To compare the efficacy and cost effectiveness of a senna-fibre combination and lactulose in treating constipation in long stay elderly patients.

A study of the use of the trimesium salt of glyphosate to desiccate and ret flax and linseed (Linum usitatissimum) and of its effects on the yield of straw, seed and fibre

A replicated field plot experiment was carried out in Northern Ireland in 1996 with flax, cv Ariane, and linseed, cv Flanders, each grown at seed rates of 500, 1000 and 1500 seeds/m(2), in which a comparison was made between netting of the standing crop, following desiccation by the trimesium salt of glyphosate (Touchdown, Zeneca Ltd.), and water or dew retting of the pulled crop. Application at 4 litres/ha on 9 August, 33 days after the mid-point of flowering (MPF), achieved both desiccation and partial retting of the crop within 14 days. Over 16 % clean long fibre was extracted by scutching the stand-netted flax straw, yielding 800 kg/ha fibre, while water retting achieved 20 extraction and 980 kg/ha yield and dew netting 8.5 % and 420 kg/ha respectively. The dew retting was uneven, resulting in high losses during fibre extraction, while water retting for 7 days at 25 degreesC did not achieve complete retting resulting in a high content of woody fragments in the fibre. Fibre yields increased by almost 50 % with the high v. low seed rate. Linseed was less well retted than flax and contained higher levels of impurity in the extracted long fibre which, after retting, yielded 120 to 310 kg/ha at extraction rates of 2.9 % to 7.5 %.

In a second experiment in 1998 flax cvs. Viola and Evelyn were treated with the timesium salt of glyphosate at rates of 2, 4 or 6 litres/ha 10, 20, 30 or 40 days after MPF on 5 July. Viola desiccated satisfactorily at all spray dates with 4 and 6 litres/ha glyphosate. The 20-day treatment desiccated more slowly than the 30-day and the 2 litres/ha rate did not achieve complete desiccation, but the trimesium salt of glyphosate achieved better desiccation at this timing than that found in earlier studies with the original form of glyphosate. Evelyn desiccated more slowly and less evenly than Viola particularly at the 20-day and 40-day timings. Spraying at MPF + 10 days interrupted early development of the seed and fibre significantly reducing yields. Due to slower desiccation the 20-day timing was no better than the 30-day, which was well retted by harvest 44 days after spraying, and gave the highest yield of clean long fibre. The spraying 40 days after MPF was considered too late in the season to be of practical use. It was concluded that retting of standing flax following desiccation with the trimesium salt of glyphosate was more effective than with the earlier formulation and that resting of the standing crop could achieve equivalent or better retting with similar fibre yields to traditional retting methods. The optimum spray timing was found to be about 30 days after MPF with 4 or 6 litres/ha, the lower rate being adequate for glyphosate responsive varieties such as Viola.

Dietary fat and breast cancer survival: a systematic review and meta-analysis

As the number of breast cancer survivors increases worldwide(1), there is growing interest in the potential effect of dietary and lifestyle behaviours on overall prognosis. This is especially important as a cancer diagnosis is often referred to as a ‘teachable moment’(2) as patients seek information about lifestyle behaviours and so provision of evidence-based guidelines is essential. A positive association between dietary fat and breast cancer risk has been previously reported(3) but its influence upon breast cancer survival is unclear. The aim of this review and meta-analysis is to critically appraise the literature published to date and to conduct meta-analyses to pool the results of studies to clarify the association between dietary fat and breast cancer survival.
Relevant articles published up to March 2011 that examined dietary fat and breast cancer recurrence and survival were identified from searches in MEDLINE and EMBASE. Meta-analyses were conducted in which we evaluated the risk of all-cause or breast cancer death in women in the highest compared with the lowest categories of total fat intake (g/d) and per 20 g increase in intake of dietary fat. Multivariable adjusted relative risks (RR) and 95% CI from individual studies were weighted and combined using a random-effects model to produce a pooled estimate.
Twelve prospective cohort studies that investigated total fat intake (g) and breast cancer survival, and/or provided information on fat intake from which a linear trend could be estimated, were included in the analyses. There was no evidence of a difference in risk of breast cancer death (RR=1.14; 95% CI 0.86, 1.52; P=0.34) or all cause death (RR=1.73; 95% CI 0.82, 3.6; P=0.15) between the highest and lowest categories of total fat intake. Similarly, no significant difference in risk of breast cancer death (RR=1.03; 95% CI 0.97, 1.10; P=0.261) or all-cause death (RR=1.06; 95% CI 0.88, 1.28; P=0.52) was found per linear (20 g) increase in total fat intake.
The results of this systematic review and meta-analysis do not support an association between total dietary fat and breast cancer survival. Further investigation into the effect of specific types of dietary fat and breast cancer survival is of interest.

Dietary fat and meat intakes and risk of reflux esophagitis, Barrett's esophagus and esophageal adenocarcinoma

The aim of our study was to investigate whether dietary fat and meat intakes are associated with reflux esophagitis (RE), Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC). In this all-Ireland case-control study, dietary intake data were collected using a food frequency questionnaire in 219 RE patients, 220 BE patients, 224 EAC patients and 256 frequency-matched controls between 2002 and 2005. Unconditional multiple logistic regression analysis was used to examine the association between dietary variables and disease risk using quartiles of intake, to attain odds ratios (ORs) and 95% confidence intervals (95% CIs), while adjusting for potential confounders. Patients in the highest quartile of total fat intake had a higher risk of RE (OR = 3.54; 95% CI = 1.32-9.46) and EAC (OR = 5.44; 95% CI = 2.08-14.27). A higher risk of RE and EAC was also reported for patients in the highest quartile of saturated fat intake (OR = 2.79; 95% CI = 1.11-7.04; OR = 2.41; 95% CI = 1.14-5.08, respectively) and monounsaturated fat intake (OR = 2.63; 95% CI = 1.01-6.86; OR = 5.35; 95% CI = 2.14-13.34, respectively). Patients in the highest quartile of fresh red meat intake had a higher risk of EAC (OR = 3.15; 95% CI = 1.38-7.20). Patients in the highest category of processed meat intake had a higher risk of RE (OR = 4.67; 95% CI = 1.71-12.74). No consistent associations were seen for BE with either fat or meat intakes. Further studies investigating the association between dietary fat and food sources of fat are needed to confirm these results.

Market Basket Survey Shows Elevated Levels of As in South Central U.S. Processed Rice Compared to California: Consequences for Human Dietary Exposure:consequences for human dietary exposure

We report the largest market basket survey of arsenic (As) in U.S. rice to date. Our findings show differences in transitional-metal levels between polished and unpolished rice and geographical variation in As and selenium (Se) between rice processed in California and the South Central U.S. The mean and median As grain levels for the South Central U.S. were 0.30 and 0.27 µg As g-1, respectively, for 107 samples. Levels for California were 41% lower than the South Central U.S., with a mean of 0.17 µg As g-1 and a median of 0.16 µg As g-1 for 27 samples. The mean and median Se grain levels for the South Central U.S. were 0.19 µg Se g-1. Californian rice levels were lower, averaging only 0.08 and 0.06 µg Se g-1 for mean and median values, respectively. The difference between the two regions was found to be significant for As and Se (General Linear Model (GLM):? As p < 0.001; Se p < 0.001). No statistically significant differences were observed in As or Se levels between polished and unpolished rice (GLM:? As p = 0.213; Se p = 0.113). No significant differences in grain levels of manganese (Mn), cobalt (Co), copper (Cu), or zinc (Zn) were observed between California and the South Central U.S. Modeling arsenic intake for the U.S. population based on this survey shows that for certain groups (namely Hispanics, Asians, sufferers of Celiac disease, and infants) dietary exposure to inorganic As from elevated levels in rice potentially exceeds the maximum intake of As from drinking water (based on consumption of 1 L of 0.01 mg L-1 In. As) and Californian state exposure limits. Further studies on the transformation of As in soil, grain As bioavailability in the human gastrointestinal tract, and grain elemental speciation trends are critical.

Variation in arsenic speciation and concentration in Paddy Rice related to Dietary Exposure

Ingestion of drinking water is not the only elevated source of arsenic to the diet in the Bengal Delta. Even at background levels, the arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets. We set out to survey As speciation in different rice varieties from different parts of the globe to understand the contribution of rice to arsenic exposure. Pot experiments were utilized to ascertain whether growing rice on As contaminated soil affected speciation and whether genetic variation accounted for uptake and speciation. USA long grain rice had the highest mean arsenic level in the grain at 0.26 µg As g-1 (n = 7), and the highest grain arsenic value of the survey at 0.40 µg As g-1. The mean arsenic level of Bangladeshi rice was 0.13 µg As g-1 (n = 15). The main As species detected in the rice extract were AsIII, DMAV, and AsV. In European, Bangladeshi, and Indian rice 64 ± 1% (n = 7), 80 ± 3% (n = 11), and 81 ± 4% (n = 15), respectively, of the recovered arsenic was found to be inorganic. In contrast, DMAV was the predominant species in rice from the USA, with only 42 ± 5% (n = 12) of the arsenic being inorganic. Pot experiments show that the proportions of DMAV in the grain are significantly dependent on rice cultivar (p = 0.026) and that plant nutrient status is effected by arsenic exposure. Ingestion of drinking water is not the only elevated source of arsenic to the diet in the Bengal Delta. Even at background levels, the arsenic in rice contributes considerably to arsenic ingestion in subsistence rice diets. We set out to survey As speciation in different rice varieties from different parts of the globe to understand the contribution of rice to arsenic exposure. Pot experiments were utilized to ascertain whether growing rice on As contaminated soil affected speciation and whether genetic variation accounted for uptake and speciation. USA long grain rice had the highest mean arsenic level in the grain at 0.26 µg As g-1 (n = 7), and the highest grain arsenic value of the survey at 0.40 µg As g-1. The mean arsenic level of Bangladeshi rice was 0.13 µg As g-1 (n = 15). The main As species detected in the rice extract were AsIII, DMAV, and AsV. In European, Bangladeshi, and Indian rice 64 ± 1% (n = 7), 80 ± 3% (n = 11), and 81 ± 4% (n = 15), respectively, of the recovered arsenic was found to be inorganic. In contrast, DMAV was the predominant species in rice from the USA, with only 42 ± 5% (n = 12) of the arsenic being inorganic. Pot experiments show that the proportions of DMAV in the grain are significantly dependent on rice cultivar (p = 0.026) and that plant nutrient status is effected by arsenic exposure.

FIBRE-OPTIC MULTICHANNEL CORRELATION/CONVOLUTION.

A fiber-optic multichannel correlator/convolver based on a two-dimensional systolic array architecture is described. Experimental verification of processor performance is presented.

Pull-out behaviour of axially loaded Basalt Fibre Reinforced Polymer (BFRP) rods bonded perpendicular to the grain of glulam elements

The behaviour of Basalt Fibre Reinforced Polymer (BFRP) loaded perpendicular to glulam timber elements was investigated. It was found that pull-out load increased approximately linearly with the bonded length up to maximum which occurred at a bonded length of 250 mm (~15 times the hole diameter) and did not increase beyond this bonded length. Failure mode of the samples was mostly shear fracture which was located at the cylindrical zone at the timber/adhesive interface. Increased bonded lengths resulted in corresponding decrease in interfacial bond stress. At 250 mm bonded length, the pull-out capacity of the proposed design model was about 2% lower than that of the tests. The results also showed that the bond stress of the theoretical model (at the ascending and descending branches) of the stress–slip curve was approximately 5–10% of that of the experiment.

A multi-fibre multi-layer representative volume element (M2RVE) for prediction of matrix and interfacial damage in composite laminates

Multiscale micro-mechanics theory is extensively used for the prediction of the material response and damage analysis of unidirectional lamina using a representative volume element (RVE). Th is paper presents a RVE-based approach to characterize the materi al response of a multi-fibre cross-ply laminate considering the effect of matrix damage and fibre-matrix interfacial strength. The framework of the homogenization theory for periodic media has been used for the analysis of a 'multi-fibre multi-layer representative volume element' (M2 RVE) representing cross-ply laminate. The non-homogeneous stress-strain fields within the M2RVE are related to the average stresses and strains by using Gauss theorem and the Hill-Mandal strain energy equivalence principle. The interfacial bonding strength affects the in-plane shear stress-strain response significantl y. The material response predicted by M2 RVE is in good agreement with the experimental results available in the literature. The maximum difference between the shear stress predicted using M2 RVE and the experimental results is ~15% for the bonding strength of 30MPa at the strain value of 1.1%