BCIT Citations Collection | BCIT Institutional Repository

BCIT Citations Collection

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Collection of published works from BCIT researchers, faculty, and instructors.

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A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol
Background: Bamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel. Results: An integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture liquor showed that an ethanol recovery of 0.46 g/g sugar was achieved with 93.2% of hydrolyzed sugars being consumed. A mass balance of the overall process showed that 76.59 g of solids was recovered from 100 g (o.d.) of green bamboo. Conclusions: The present work proposes an integrated biorefinery process that contains alkaline pre-extraction, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, thereby allowing the improvement and expansion of bamboo utilization in industrial processes., Peer-reviewed article, Published. Received: 22 November 2016 ; Accepted: 2 February 2017 ; Published: 10 February 2017.
Brain-computer interface design for asynchronous control applications
The low-frequency asynchronous switch design (LF-ASD) was introduced as a direct brain-computer interface (BCI) technology for asynchronous control applications. The LF-ASD operates as an asynchronous brain switch (ABS) which is activated only when a user intends control and maintains an inactive state output when the user is not meaning to control the device (i.e., they may be idle, thinking about a problem, or performing some other action). Results from LF-ASD evaluations have shown promise, although the reported error rates are too high for most practical applications. This paper presents the evaluation of four new LF-ASD designs with data collected from individuals with high-level spinal cord injuries and able-bodied subjects. These new designs incorporated electroencephalographic energy normalization and feature space dimensionality reduction. The error characteristics of the new ABS designs were significantly better than the LF-ASD design with true positive rate increases of approximately 33% for false positive rates in the range of 1%-2%. The results demonstrate that the dimensionality of the LF-ASD feature space can be reduced without performance degradation. The results also confirm previous findings that spinal cord-injured subjects can operate ABS designs to the same ability as able-bodied subjects., Peer-reviewed article, Published. Manuscript received June 30, 2003; revised February 6, 2004.
Brain interface research for asynchronous control applications
The Neil Squire Society has developed asynchronous, direct brain switches for self-paced control applications with mean activation rates of 73% and false positive error rates of 2%. This report summarizes our results to date, lessons learned, and current directions, including research into implanted brain interface designs., Peer-reviewed article, Published. Manuscript received July 16, 2005; revised March 15, 2006; March 20, 2006.
The business case for accessible workplaces
The article focuses on the cost-benefit findings for ensuring workplaces are made accessible to disabled employees. Topics discussed include accessibility to workplaces in Canada; determining the financial benefit of built environment accommodations through employee retention; and savings in employee retention and retraining costs., Article, Published.
CAD-CAM applications for spinal orthotics
In the summer of 1988, a joint study was done by the Prosthetics and Orthotics Department at the British Columbia Institute of Technology and the Medical Engineering Resource Unit (MERU) of the University of British Columbia. The study was undertaken to determine the feasibility of applying existing Computer Aided Design-Computer Aided Manufacture (CAD-CAM) techniques to the design and manufacture of spinal orthoses. The orthosis design selected was a TLSO for the treatment of a non-structural curve of the spine. The results of the study were very promising. This paper describes the study and discusses the results., Peer-reviewed article, Published.
A Canada-wide survey of chronic respiratory disease and spinal cord injury
With advances in acute care for individuals with spinal cord injury (SCI), chronic conditions are becoming a central focus.1–3 More specifically, impairments in respiratory function are one of the leading causes of morbidity and mortality among individuals with SCI,4 and have significant economic burden. Paresis or paralysis of the respiratory muscles can lead to respiratory insufficiency, which has a major impact on cough effectiveness and susceptibility to infection.5–7 Prior studies have typically focused on breathing mechanics and pneumonia in the acute stages of SCI, but there is a dearth of evidence regarding secondary chronic conditions, such as asthma and chronic obstructive pulmonary disease (COPD), among SCI populations. In the general population, risk factors for the development of asthma and COPD include genetic, sociodemographic, and environmental components.8,9 In addition, traffic pollution and occupational exposures, and indoor exposure to pollutants such as mold, increase susceptibility to both diseases. However, that SCI may be an independent risk factor for COPD and asthma (or vice versa) has not been previously examined. It thus remains unknown whether there is a higher prevalence of chronic respiratory diseases (after adjustment for potential confounders) in individuals with SCI. The current study addresses this knowledge gap by utilizing the national Canadian Community Health Survey, which comprises comprehensive, up-to-date, cross-sectional data. Our aim was to estimate the prevalence of chronic respiratory outcomes in the SCI population, to compare their odds with a non-SCI population, and to investigate this relationship after controlling for confounders., Peer-reviewed article, Published. Received September 18, 2014; Accepted December 09, 2014.
Carbonation in concrete infrastructure in the context of global climate change
A number of recent studies have identified and begun to quantify increased susceptibility of the infrastructure to climate change–induced carbonation of reinforced concrete. In this paper, the results of a study are presented which uses an updated empirical model to predict the diffusion coefficient of carbon dioxide (CO2) in concrete and thereafter, predict carbonation depths for a number of urban environments in the United States. Data from newer climate forecasts from the 5th Intergovernmental Panel on Climate Change assessment report are used to generate predictions for carbonation depths in four U.S. cities of varying geographic and climatic conditions (Los Angeles, Houston, Chicago, New York City). Results confirm that carbonation depths will increase in the future because of climate change. The magnitude of the increase is dependent on the climate-change scenario considered and the geographic location of the city. Whether or not the increases will require building code changes to increase concrete cover or improve concrete quality will be dependent on actual construction practices for the city in question., Peer-reviewed article, Published. Received: January 05, 2015; Accepted: July 30, 2015; Published online: October 28, 2015.
Carbonation in concrete infrastructure in the context of global climate change
There is nearly unanimous consensus amongst scientists that increasing greenhouse gas emissions, including CO2 generated by human activity, are effecting the Earth’s climate. Increasing atmospheric CO2 emissions will likely increase the rates of carbonation in reinforced concrete structures. However, there is a lack of reliable models to predict the depth of carbonation as a function of time. To address this deficiency, a numerical model involving simultaneous solution of the transient diffusion and reaction equations of CO2 and Ca(OH)2 was developed. The model successfully includes the effects of variations in various properties such as porosity, humidity, temperature, atmospheric CO2 concentrations and chemical reaction rates. The applicability of the model was confirmed after calibration using data from accelerated carbonation experiments, and the model is used to evaluate the possible effects of climate change by inputting various future climate scenarios in Part 2., Peer-reviewed article, Published.
Carbonation in concrete infrastructure in the context of global climate change
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.
Carbonation in concrete infrastructure in the context of global climate change
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.
Cardiovascular disease and spinal cord injury
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.
Characterizing the community use of an ultralight wheelchair with "on the fly" adjustable seating functions
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.
Climate change-induced carbonation of concrete infrastructure
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.
A comparative study on generating training-data for self-paced brain interfaces
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.
A comparison between the effects of ozone and alkaline peroxide treatments on TMP properties and subsequent low consistency refining
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.
Comparisons of large (Vaccinium macrocarpon ait.) and small (Vaccinium oxycoccos L., Vaccinium vitis-idaea L.) cranberry in British Columbia by phytochemical determination, antioxidant potential, and metabolomic profiling with chemometric analysis
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.

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