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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Investigation of the moisture buffering potential of magnesium oxide board
Research report submitted to Peter Francis, President, MAGO Building Products Ltd in April 2016. Passive humidity control in buildings can be achieved by incorporating materials with moisture buffering potential in that these materials absorb moisture at peak times and give off the stored up moisture at low moisture production times thereby stabilizing the interior relative humidity. Some of the advantages of this phenomenon include but are not limited to energy savings, improvement of thermal comfort and perceived air quality. As such, it is necessary to investigate different materials for their moisture buffering capabilities. As part of product development, the moisture buffering characteristics of Magnesium oxide board (Magnesia board) is experimentally investigated. Other considerations such as the impact of surface finishing and ventilation are also assessed. The experiment is done by monitoring twin buildings termed the Whole Building Performance Research Laboratory (WBPRL) while measuring the relative humidity evolution in time. One is set as the reference building and finished with gypsum wallboard owing to its wide industry use. The other is set as the reference building and covered with the Magnesia board. Both buildings are first validated under non-hygroscopic conditions to ensure similar hygrothermal loading and operation of both buildings. Next, four tests are conducted to simulate surface treatments, ventilation effects, and occupancy density. For each test run, four cases are created for different surface treatment configurations. From the test, it is found that magnesia board and gypsum demonstrate similar moisture buffering characteristics. In the as-in service case where the gypsum wallboard is painted with latex paint, as it is the current common practice, and magnesia board with the company specified paint, the later demonstrates slightly better moisture buffering due to the high permeability surface treatment., Research report, Published.
Iterated belief change due to actions and observations
In action domains where agents may have erroneous beliefs, reasoning about the effects of actions involves reasoning about belief change. In this paper, we use a transition system approach to reason about the evolution of an agent's beliefs as actions are executed. Some actions cause an agent to perform belief revision while others cause an agent to perform belief update, but the interaction between revision and update can be non-elementary. We present a set of rationality properties describing the interaction between revision and update, and we introduce a new class of belief change operators for reasoning about alternating sequences of revisions and updates. Our belief change operators can be characterized in terms of a natural shifting operation on total pre-orderings over interpretations. We compare our approach with related work on iterated belief change due to action, and we conclude with some directions for future research., Peer-reviewed article, Published.
Lessons learnt from the shotcrete repair of the Powell River concrete hulks, and their applicability to other marine structures
Background : Concrete structures can be damaged by many chemical or physical processes. Where such damages affect appearance, serviceability or structural integrity, repair may be required. 10 decommissioned concrete ships form a massive floating breakwater on the Malaspina Strait in the City of Powell River in British Columbia, Canada. The ships are subjected to extremely onerous conditions, namely in the salt water splash zone under seasonal freeze-thaw cycling. This paper provides anecdotal evidence based on condition assessments after repairs were car-ried out, on how a well-matched repair concrete can significantly extend the service life of these and similar sorts of marine structures. Methods: Condition assessment was carried out using sounding, visual examination, photo and video documentation, compressive strength testing, splitting tensile strength testing, chloride ion concentration testing, and half-cell potential testing. Results: It was found that the areas which had been repaired had fared very well, with no observable de-terioration. The non-repaired areas of the structures had continued to deteriorate, particularly in non-submerged areas, close to the waterline, along with new impact damage. Conclusion: Durable concrete repairs can be achieved even for concrete exposed to extreme environ-mental conditions. Key conditions for such repairs are: complete removal of the deteriorated portions of the original concrete, removal of all loose corrosion products from exposed reinforcing steel, prepara-tion of a clean, firm, rough, surface dry but partially or fully water saturated, substrate surface, selection of a compatible repair material, use of an application technique which facilitates high bond strength between substrate and repair material, adequate curing, and protection of the repair material while immature., Peer-reviewed article, Published. Received: September 12, 2015; Revised: December 19, 2015; Accepted: June 28, 2016.
Limiting cases for spectrum closure results
The spectrum of a first-order sentence is the set of cardinalities of its finite models. Given a spectrum S and a function f, it is not always clear whether or not the image of S under f is also a spectrum. In this paper, we consider questions of this form for functions that increase very quickly and for functions that increase very slowly. Roughly speaking, we prove that the class of all spectra is closed under functions that increase arbitrarily quickly, but it is not closed under some natural slowly increasing functions., Peer-reviewed article, Published.
Long-term effects of spinal cord injury on sexual function in men
Study Design: Secure, web-based survey. Objectives: Elicit specific information about sexual function from men with spinal cord injuries (SCI). Setting: World-wide web. Methods: Individuals 18 years or older living with SCI obtained a pass-code to enter a secure website and then answered survey questions. Results: The presence of genital sensation was positively correlated with the ability to feel a build up of sexual tension in the body during sexual stimulation and in the feeling that mental arousal translates to the genitals as physical sensation. There was an inverse relationship between developing new areas of arousal above the level of lesion and not having sensation or movement below the lesion. A positive relationship existed between the occurrence of spasticity during sexual activity and erectile ability. Roughly 60% of the subjects had tried some type of erection enhancing method. Only 48% had successfully achieved ejaculation postinjury and the most commonly used methods were hand stimulation, sexual intercourse, and vibrostimulation. The most commonly cited reasons for trying to ejaculate were for pleasure and for sexual intimacy. Less than half reported having experienced orgasm postinjury and this was influenced by the length of time postinjury and sacral sparing. Conclusion: SCI not only impairs male erectile function and ejaculatory ability, but also alters sexual arousal in a manner suggestive of neuroplasticity. More research needs to be pursued in a manner encompassing all aspects of sexual function., Peer-reviewed article, Published.
Low consistency refining of oxalic acid pretreated wood shavings
The objective of this study was to evaluate the potential use of wood shavings as a raw material for the low consistency (LC) refining at the primary refining stage to significantly reduce electrical energy consumption. It was possible to produce wood shavings with longer fibre length than wood chips. Oxalic acid, followed by alkaline peroxide, was applied to both wood shavings and wood chips before LC refining. LC refined wood shavings were found to be a low energy raw material. The refining energy was reduced by about 33% using wood shavings compared to wood chips at a given freeness, and oxalic acid pretreatment of wood shavings further reduced the refining energy by approximately 57%. Tensile strength and brightness of LC refined wood shavings was found to be higher than high-consistency refined wood chips. Oxalic acid pretreatment further improved the tensile strength of LC refined wood shavings, but not the brightness. This study demonstrates the potential to develop a novel mechanical pulping process that produces high tensile, high brightness pulp with half the electrical energy consumption. Both wood chips and wood shavings produced in the laboratory were used as a feeding material in HC and LC refining processes, respectively. Fibre length of wood shavings was longer than that of wood chips. As refining proceeded, fibre length of LC refined wood shavings was reduced more than that of HC refined wood chips. Oxalic acid pretreatment further reduced the fibre length of LC refined wood shavings. A great advantage of using wood shavings was found in reducing refining energy over wood chips. LC refined wood shavings reduced the refining energy about 33% compared to HC refined wood chips at a given freeness. Oxalic acid followed by alkaline peroxide pretreatment of wood shavings further reduced refining energy by approximately 57%., Peer-reviewed article, Published.
Lycopene differentially induces quiescence and apoptosis in androgen-responsive and -independent prostate cancer cell lines
Background & aims: Lycopene has been credited with a number of health benefits including a decrease in prostate cancer risk. Our study investigates the molecular mechanism underlying anti-cancer activity of lycopene-based products in androgen-responsive (LNCaP) and androgen-independent (PC3) cells. Methods: The effect of lycopene-based agents on prostate cancer growth and survival were examined using proliferation assays, bromodeoxyuridine incorporation and flow cytometric analysis of cellular DNA content. Biochemical effects of lycopene treatment were investigated by immunoblotting for changes in the absolute levels and phosphorylation states of cell cycle regulatory and signalling proteins. Results: LNCaP and PC3 cells treated with the lycopene-based agents undergo mitotic arrest, accumulating in G0/G1 phase. Immunoblot screening indicated that lycopene's antiproliferative effects are likely achieved through a block in G1/S transition mediated by decreased levels of cyclins D1 and E and cyclin dependent kinase 4 and suppressed Retinoblastoma phosphorylation. These responses correlated with decreased insulin-like growth factor-I receptor expression and activation, increased insulin-like growth factor binding protein 2 expression and decreased AKT activation. Exposure to lycopene at doses as low as 10nM for 48h induced a profound apoptotic response in LNCaP cells. In contrast PC3 cells were resistant to apoptosis at doses up to 1μM. Conclusions: Lycopene exposure can suppress phosphatidylinositol 3-kinase-dependent proliferative and survival signalling in androgen-responsive LNCaP and androgen-independent PC3 cells suggesting that the molecular mechanisms for the cytostatic and cytotoxic actions of lycopene involve induction of G0/G1 cell cycle arrest. This study supports further examination of lycopene as a potential agent for both the prevention and treatment of prostate cancer., Peer-reviewed article, Published.
Lz-0 × Berkeley
This study describes the generation and test of a genetic resource suited to identify determinants of cell biological traits in plants. The use of quantitative trait loci (QTL) mapping for a better genetic understanding of cell biological traits is still at an early stage, even for biotechnologically important cell properties, such as the dimensions of fiber cells. A common strategy, the mapping of QTLs in recombinant inbred line (RIL) populations, is limited by the fact that the existing RIL populations exploit only a small fraction of the existing natural variation. Here, we report the mapping of QTLs impacting on the length of fiber cells in Arabidopsis inflorescence stems in a newly generated RIL population derived from a cross between the accessions Berkeley and the little known Lz-0. Through inbreeding of individual F(2) plants, a total of 159 new F8 lines were produced and genotyped with a set of 49 single nucleotide polymorphism markers. The population was successfully used not only for the mapping of three QTLs controlling fiber length, but also to map five QTL controlling flowering time under short and long-day conditions. Our study demonstrates the usefulness of this new genetic resource by mapping in it QTLs underlying a poorly explored cellular trait as well as an already better explored regulatory pathway. The new RIL population and an online platform for the continuous supplementation of genetic markers will be generally available to substantially broaden the genetic diversity through which loci with impact on plant quantitative traits can be identified., Peer-reviewed article, Published. Received: 1 October 2012, Accepted: 25 January 2014; Published online: 15 February 2014.
Magneto-optical trap loading rate dependence on trap depth and vapor density
We study the dependence of the particle loading rate of a rubidium vapor cell magneto-optic trap (MOT). Using a trap depth determination of the MOT that relies on measurements of loss rates during optical excitation of colliding atoms to a repulsive molecular state, we experimentally determine the MOT escape velocity and show that the loading rate scales with escape velocity to the fourth power, or, equivalently, with the square of the trap depth. We also demonstrate that the loading rate is directly proportional to the background rubidium density. We thus experimentally confirm the loading rate model used in the literature since the invention of the MOT. In addition to confirming this long-standing conjecture, we show that the loading rate dependence can be used to reliably infer the trap depth and to tune the relative depth of a MOT (i.e., capture and escape velocities) when the background density is held fixed. The measurements have allowed an experimental determination of the relationship between capture and escape velocities in our MOTs of 𝑣𝑐=1.29(0.12)𝑣𝑒., Peer-reviewed article, Published.
Maintaining apical dominance in the fern gametophyte
A kinetic model is developed for cell differentiation in the fern gametophyte to test hypotheses on the role of spatially patterned plasmodesmata networks in development. Of particular interest is the establishment and maintenance of apical cell type in a single cell, with concurrent suppression of this character in all other cells (apical dominance). Steps towards understanding apical cell localization in geometrically simple gametophytes may shed light on the establishment and maintenance of apical meristems in higher plants. The model, based on the plasmodesmata maps of Tilney and colleagues and involving kinetics for a requisite minimum of two morphogens, successfully produces the apical/non‐apical cell differentiation patterns of normal development, and redifferentiation due to cell isolation, in six stages from 0–30 d of development. Our results indicate that increasing apical cell plasmodesmata number, as development progresses, is not required for effective transport across apical cell walls in maintaining apical dominance., Peer-reviewed article, Published. Received: 3 August 2001; Returned for revision: 12 November 2001; Accepted: 17 December 2001.
Maintenance scheduling of Volt-VAR control assets in smart distribution networks using advanced metering infrastructure
This paper investigates a novel approach for maintenance scheduling of volt-VAR control components (VVCCs) of distribution networks with the aid of new generation of volt-VAR optimization (VVO) solutions called quasi-real-time VVO. The new quasi-real-time VVO technique optimizes distribution network using advanced metering infrastructure (AMI) data of each quasi-real-time stage. As this VVO performs automatically and online, it is necessary for VVCCs to undergo maintenance without disturbing VVO performance. Moreover, the lost benefits that could be gained by online VVO have to be minimized. Hence, this paper proposes an AMI-based VVO consisting of a VVO engine and a maintenance scheduling engine (MSE) that operate in tandem to optimize distribution network and find the optimal maintenance scheduling of different VVCCs. To test the accuracy and the applicability of the proposed solution, a 33-node distribution feeder is employed. Furthermore, five different maintenance scenarios are investigated to check the proposed VVO performance. The results prove that the integration of VVO with MSE could be a reliable approach that can solve maintenance scheduling of VVCCs without interrupting and/or resetting VVO., Article, Published
Making the body plan
We quantify fluctuations in protein expression for three of the segmentation genes in the fruit fly, Drosophila melanogaster. These proteins are representative members of the first three levels of a signalling hierarchy which determines the segmented body plan: maternal (Bicoid protein); gap (Hunchback protein); and pair-rule (Even-skipped protein). We quantify both inter-embryo and inter-nucleus (within a single embryo) variability in expression, especially with respect to positional specification by concentration gradient reading. Errors are quantified both early and late in cleavage cycle 14, during which the protein patterns develop, to study the dynamics of error transmission. We find that Bicoid displays very large positional errors, while expression of the downstream genes, Hunchback and Even-skipped, displays far more precise positioning. This is evidence that the pattern formation of the downstream proteins is at least partially independent of maternal signal, i. e. evidence against simple concentration gradient reading. We also find that fractional errors in concentration increase during cleavage cycle 14., Peer-reviewed article, Published. Received 30 September 2002; Accepted 12 December 2002; Published 16 December 2002.
A mammalian artificial chromosome engineering system (ACE System) applicable to biopharmaceutical protein production, transgenesis and gene-based cell therapy
Mammalian artificial chromosomes (MACs) provide a means to introduce large payloads of genetic information into the cell in an autonomously replicating, non-integrating format. Unique among MACs, the mammalian satellite DNA-based Artificial Chromosome Expression (ACE) can be reproducibly generated de novo in cell lines of different species and readily purified from the host cells' chromosomes. Purified mammalian ACEs can then be re-introduced into a variety of recipient cell lines where they have been stably maintained for extended periods in the absence of selective pressure. In order to extend the utility of ACEs, we have established the ACE System, a versatile and flexible platform for the reliable engineering of ACEs. The ACE System includes a Platform ACE, containing >50 recombination acceptor sites, that can carry single or multiple copies of genes of interest using specially designed targeting vectors (ATV) and a site-specific integrase (ACE Integrase). Using this approach, specific loading of one or two gene targets has been achieved in LMTK− and CHO cells. The use of the ACE System for biological engineering of eukaryotic cells, including mammalian cells, with applications in biopharmaceutical production, transgenesis and gene-based cell therapy is discussed., Peer-reviewed article, Publsihed.
The marihuana indoor production calculator
The clandestine nature of illicit indoor marihuana production makes is difficult to measure the true extent of marihuana cultivation in a given policing jurisdiction. As a result, law enforcement must rely on estimations in order to understand the scale of the problem in terms of the number of growing operations, the number of growers, or the monetary value of the industry. This article describes an online estimation tool that was developed to aid law enforcement in the estimation of the annual production, domestic sale, exportation, and total value of marihuana produced in commercial growing operations within a given jurisdiction., Research article, Published.
Measurement of anomalous dispersion in molecular iodine vapour by a simple interferometric method
The index of refraction of iodine vapour was measured in regions of anomalous dispersion. These measurements were made using a Michelson interferometer illuminated by a tunable dye laser, and encompass 30 GHz regions centered near 17 408.3 and 17 565.1 cm−1. These regions contained several rovibrational lines of the transition, and at a vapour pressure of 0.28 Torr (1 Torr = 133.3 Pa) the index of refraction near these lines was found to vary by a few parts in 107., Peer-reviewed article, Published.
Measurement of the sound absorption characteristics of vegetative roofs
Vegetative roofs have the potential to provide excellent external/internal sound isolation due to their high mass, low stiffness and their damping effect, and to provide a high level of sound absorption due to the low impedance of the vegetative substrate layer. The acoustical characteristics of vegetative roofs provide ecological contributions to the urban environment through a reduction of noise pollution from aircraft, elevated transit systems, and industrial noise. Vegetative roofs can reduce sound transmission into the interior of buildings, contributing to improved room acoustics through a reduction in noise and hence a reduction in distraction and stress (Connelly & Hodgson 2008). Through surface absorption, vegetative roofs will affect the propagation and build-up of positive and negative sounds and reduce reverberation in enclosed rooftop areas, altering the quality of the soundscape and the habitability of rooftops. Vegetative roofs can be comprised of various material layers: root barrier, water reservoir/drainage layer, filter fabric, substrates and plants. The layer thought to have the most significant effect on the vegetative roof’s acoustical characteristics is the layer of the vegetation and substrate. The vegetative substrate is complex to characterize; it varies in terms of the depth of substrate, the substrate constituents and physical properties, the plant’s aerial biomass and root structure, as well as the dynamic in-situ microclimatic and conditions which vary over season and time., Article, Published.

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