In Part1 of this paper, a carbonation model was developed and experimentally veriﬁed which was able to forecast carbonation depth of a concrete specimen considering varying ambient temperature, humidityand CO2 concentrations. Part 2 of the paper applies the carbonation diffusion/reaction model developed in Part 1 to predict the effects of global climate change on the carbonation of concrete. Climate scenarios were formulated and combined with the model for two major Canadian cities, Toronto and Vancouver. Results show that for undamaged and unstressed concrete, climate change will signiﬁcantly affect carbonation progress. The model showed that for unloaded, non-pozzolanic concrete, ultimate carbonation depths in Toronto and Vancouver could be up to 45% higher. For in-service structures under load, the rates of deterioration are likely to be even faster. This is a cause for concern, and much further effort must be devoted to fully understand these phenomena., Peer-reviewed article, Published. Received 18 October 2011; Revised 21 April 2012; Accepted 24 April 2012; Available online 10 May 2012.
There is nearly unanimous consensus amongst scientists that increasing greenhouse gas emissions, including CO2 generated by human activity, are affecting the Earth’s climate. Increasing atmospheric CO2 emissions will likely increase the rates of carbonation in reinforced concrete structures.In this paper, the serviceable life, from construction through to cracking due to carbonation induced corrosion of concrete infrastructure is considered in various cities throughout the world. It was concluded that global climate change will affect the progression and will result in much higher ultimate carbonation depths in the long term., Peer-reviewed article, Published. Received 23 May 2012; Revised 1 October 2012; Accepted 9 November 2012; Available online 25 December 2012.
Over the last decade, there have been marked changes in the trends of morbidity and mortality among individuals with spinal cord injury (SCI). With advances in acute care and in the management of septicemia, renal failure, and pneumonia, cardiovascular complications are now a leading cause of death in those with SCI.1 Moreover, several risk factors for cardiovascular disease (CVD) are amplified in individuals with SCI compared with able-bodied individuals, including physical inactivity, dyslipidemia, blood pressure irregularities, chronic inflammation, and abnormal glycemic control.2–22. While most of the literature with respect to CVD and SCI has shown a higher prevalence of risk factors for CVD,2–22 relatively few studies have examined the prevalence of CVD itself and corresponding risk estimates.23–26 None of these studies has provided direct comparisons of risk estimates for multiple CVD outcomes in the SCI population compared to a non-SCI population, with appropriate adjustment for confounding, in a large representative sample. It thus remains unknown whether there is excess risk of both heart disease and stroke (after adjustment for potential confounders) in individuals with SCI. The current study addresses this knowledge gap by utilizing the national Canadian Community Health Survey (CCHS), which is comprised of comprehensive, up-to-date, cross-sectional data. Our aim was to estimate the prevalence of heart disease and stroke outcomes in the SCI population, to compare their risk with a non-SCI population, and to investigate this relationship after controlling for confounders., Peer-reviewed article, Published. Received December 02, 2012 ; Accepted April 22, 2013.
An ultralight manual wheelchair that allows users to independently adjust rear seat height and backrest angle during normal everyday usage was recently commercialized. Prior research has been performed on wheelchair tilt, recline, and seat elevation use in the community, however no such research has been done on this new class of manual ultralight wheelchair with "on the fly" adjustments. The objective of this pilot study was to investigate and characterize the use of the two adjustable seating functions available on the Elevation™ ultralight dynamic wheelchair during its use in the community. Eight participants had data loggers installed onto their own wheelchair for seven days to measure rear seat height, backrest angle position, occupied sitting time, and distance traveled. Analysis of rear seat height and backrest adjustment data revealed considerable variability in the frequency of use and positions used by participants. There was a wide spread of mean daily rear seat heights among participants, from 34.1 cm to 46.7 cm. Two sub-groups of users were further identified: those who sat habitually at a single typical rear seat height, and those who varied their rear seat height more continuously. Findings also showed that participants used the rear seat height adjustment feature significantly more often than the backrest adjustment feature. This obvious contrast in feature use may indicate that new users of this class of wheelchair may benefit from specific training. While the small sample size and exploratory nature of this study limit the generalizability of our results, our findings offer a first look at how active wheelchairs users are using a new class of ultralight wheelchair with "on the fly" seating adjustments in their communities. Further studies are recommended to better understand the impact of dynamic seating and positioning on activity, participation and quality of life., Peer-reviewed article, Published. Received: April 28, 2016; Accepted: February 26, 2017; Published: March 9, 2017.
There is a nearly unanimous consensus among scientists that increasing greenhouse gas emissions, primarily carbon dioxide generated by human activity, are effecting the Earth's climate. For many key parameters, the climate system is already moving beyond the patterns of natural variability within which our societies and economies have developed and thrived. These parameters include global mean surface temperature, sea-level, ocean and ice sheet dynamics, and extreme climatic events. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts. One overlooked area of research is the impact of climate change on concrete infrastructure. Concrete structures form an essential part of the world. Climate change could potentially affect the durability of concrete infrastructure. In this paper, the findings of a study at the University of British Columbia which demonstrate a long-term risk to the durability of steel-reinforced concrete structures in some parts of the world via accelerated carbonation-induced corrosion are presented. Research demonstrates that service lifespans of structures will be affected in the long term, with the need for earlier repairs unless the adverse effects of climate change are taken into account at the time of design., Peer-reviewed article, Published.
Direct brain interface (BI) systems provide an alternative communication and control solution for individuals with severe motor disabilities, bypassing impaired interface pathways. Most BI systems are aimed to be operated by individuals with severe disabilities. With these individuals, there is no observable indicator of their intent to control or communicate with the BI system. In contrast, able-bodied subjects can perform the desired physical movements such as finger flexion and one can observe the movement as the indicator of intent. Since no external knowledge of intention is available for individuals with severe motor disabilities, generating the data for system training is problematic. This paper introduces three methods for generating training-data for self-paced BI systems and compares their performances with four alternative methods of training-data generation. Results of the offline analysis on the electroencephalogram data of eight subjects during self-paced BI experiments show that two of the proposed methods increase true positive rates (at fixed false positive rate of 2%) over that of the four alternative methods from 50.8%-58.4% to about 62% which corresponds to 3.6%-11.2% improvement., Peer-reviewed article, Published. Manuscript received June 26, 2006; Revised October 27, 2006; Accepted December 6, 2006.
As part of a program to reduce electrical energy consumption in the refining process, the effects of the ozone and alkaline peroxide treatments on fibre and handsheet properties, prior and subsequent to low consistency (LC) refining, were assessed and compared by applying different levels of ozone and a range of peroxide and alkali charges to a primary stage hemlock thermomechanical pulp (TMP). Both highly alkaline peroxide treatments and ozone treatments decreased the specific energy required for strong mechanical pulp. The improvement in pulp strength through alkaline peroxide treatment mainly resulted from pulp surface changes caused by generation of acid groups. The highly alkaline peroxide treatments significantly increased pulp brightness but did not promote the further fibrillation during the subsequent LC refining. On the other hand, ozone treatments provided tensile strength increases, along with small brightness enhancements for the dark hemlock TMP, and increased the tensile gains obtained through LC refining. The effects of ozone treatments on tensile strength before and after LC refining were the result of pulp surface modifications, fibre swelling, and loss of fibre wall integrity due to non-selective chemical attack. High levels of ozone treatment caused tear strength to decrease during subsequent LC refining., Peer-reviewed article, Published.
There is a long history of use and modern commercial importance of large and small cranberries in North America. The central objective of the current research was to characterize and compare the chemical composition of 2 west coast small cranberry species traditionally used (Vaccinium oxycoccos L. and Vaccinium vitis-idaea L.) with the commercially cultivated large cranberry (Vaccinium macrocarpon Ait.) indigenous to the east coast of North America. V. oxycoccos and V. macrocarpon contained the 5 major anthocyanins known in cranberry; however, the ratio of glycosylated peonidins to cyanidins varied, and V. vitis-idaea did not contain measurable amounts of glycosylated peonidins. Extracts of all three berries were found to contain serotonin, melatonin, and ascorbic acid. Antioxidant activity was not found to correlate with indolamine levels while anthocyanin content showed a negative correlation, and vitamin C content positively correlated. From the metabolomics profiles, 4624 compounds were found conserved across V. macrocarpon, V. oxycoccos, and V. vitis-idaea with a total of approximately 8000–10 000 phytochemicals detected in each species. From significance analysis, it was found that 2 compounds in V. macrocarpon, 3 in V. oxycoccos, and 5 in V. vitis-idaea were key to the characterization and differentiation of these cranberry metabolomes. Through multivariate modeling, differentiation of the species was observed, and univariate statistical analysis was employed to provide a quality assessment of the models developed for the metabolomics data., Peer-reviewed article, Published.
The overall U-factor values for an attic assembly are usually computed with the ANSI/ASHRAE/IES based R-value (thermal resistance) conversion. In the ANSI/ASHRAE/IES Standard 90.1 (2010), the effects of attic air resistance, roof pitch and attic width are not taken into account while calculating the U-Factor values. In addition, the R-value is estimated using a one dimensional thermal resistance model. In ventilated attics, where the insulation near the roof sheathing is tapered, it is difficult to find the correct R-value of the attic system as the heat transfer becomes two dimensional. In this paper, a 2-dimensional CFD model is developed for various insulation R-values and insulation taper angles near roof decks. COMSOL Multiphysics 4.4 is used to model and analyse the attic structure. Results show that a discrepancy in overall U-factor for entire attic assembly between the developed model and the existing standard estimation. These results are pronounced for lower slope roofs with high insulation thickness., Peer-reviewed article, Published. Available online 30 December 2015.
This paper reports modelling of heart localization in the axolotl (Ambystoma mexicanum). The region of heart specification in the mesoderm defined by classical induction from the endoderm is larger than the area of final myocardial differentiation. For localizing the area of differentiation within the area of specification, we postulate a mesoderm in response to induction from the endoderm. This mechanism generates a spatial pattern for two chemicals, an activator and an inhibitor, corresponding to the area of myocardial differentiation. We postulate a diffusible chemical rescuer, which is absent in the cardiac lethal mutant, and which is a precursor to the reaction-diffusion mechanism. The activator, inhibitor, rescuer, and product of endodermal induction are presented in an enzyme mechanism with rate equations similar to the Gierer-Meinhardt equations. These equations were solved numerically in both one and two spatial dimensions. We have attained quantitative agreement with the experimental data for sizes of tissue regions and for times to heartbeat. Experiments modelled include wild-type heart localization as well as both in vitro and in vivo rescue of cardiac lethal mesoderm with wild-type mesoderm. Based upon the parameters necessary to model heart localization, we make a series of predictions. We predict: a specific profile for the endodermal inducer gradient; the possibility of producing multiple hearts in vivo; and a greater contribution to the heart from the wild-type mesoderm for in vivo transplants with cardiac lethal mesoderm. We make some suggestions as to the possible chemical nature of the substances in the model. We indicate that the inhibitory field and mechanochemical theories are probably not as promising as reaction-diffusion for the mechanism of heart localization., Peer-reviewed article, Published. Received January 24, 1994; accepted April 7, 1994.
Curcuma longa L. rhizomes are used extensively as a spice in food preparations and dietary supplements for their anti-inflammatory and antioxidant properties. An expert review panel (ERP) evaluated analytical methods for the quantitation of individual curcuminoids for the purpose of identifying a method for official method status. It was requested that several modifications be undertaken to improve method performance prior to subjecting the chosen method to a single-laboratory validation. Two separate Plackett-Burman factorial studies were used to identify factors that contributed to the chromatographic separation and extraction of curcuminoids. Significant factors were further optimized to produce the improved HPLC method for curcuminoid separation. This method was then subjected to a single-laboratory validation according to the AOAC International guidelines for linearity, detection limits, precision, and accuracy. The two most significant factors impacting the quantitation of curcuminoids were column temperature and extraction solvent, which were optimized to 55 °C and 100 % methanol, respectively. The validation was performed on 12 raw materials and finished products containing turmeric roots. The method precision was reported using HorRat values which were within recommended ranges of the AOAC guidelines. Overall accuracy of the method was accessed at three separate levels for each analyte and ranged from 99.3–100.9 %. The validated method is suitable for quantitation of individual curcuminoids in turmeric raw materials and finished products and is recommended for consideration as an official method by the AOAC International., Peer-reviewed article, Published. Received 13 July 2015; Accepted 21 September 2015; Published online 29 September 2015.
The demand for validated analytical methods for botanicals has grown in response to the increasing consumer market for botanical supplements. Government initiatives to increase the availability of validated analytical methods and botanical reference material have led to the publication of numerous validation studies in scientific journals. Single laboratory validation and collaborative validation studies are structured to confirm a method's ruggedness and fit for purpose. The performance characteristics and statistical protocols followed throughout a validation study vary with the source of guidelines. Analytical techniques and priority methods are influenced by the need for fast-screening techniques, the limited availability of reference material, market value, and the prevalence of contaminants in botanical supplements., Peer-reviewed article, Published.