Glacier contribution to the North and South Saskatchewan Rivers

The hydrological model WATFLOOD and a volume-area scaling relationship are applied to estimate glacier wastage and seasonal Melt contribution to the headwaters of the North and South Saskatchewan Rivers on the eastern slopes of the Canadian Rocky Mountains from 1975-1998. Wastage is defined as the annual volume of glacier ice melt that exceeds the annual volume of snow accumulation into the glacier system, causing an annual net loss of glacier volume. Melt is defined as the annual volume of glacier ice melt that is equal to, or less than, the annual volume of snow that does not melt from the glacier and instead accumulates into the glacier system. It is proposed that the distinction between these two components of glacier runoff is important in studies of the impact of glacier variations on flow. A comparison of similar glacierised and non-glacierised basin hydrographs shows that glacierised basins have greater specific streamflow in the late summer months of otherwise low flow, and the presence of glaciers in a basin results in a lower coefficient of variation of the July to September and annual streamflow as a result of the natural regulating impact of glaciers on streamflow. Glacier wastage and Melt are estimated from a hydrological-hypsometric comparison of glacierised and non-glacierised basins, mass balance data from Peyto Glacier and the published work of other researchers. The similarity of these results to those from the volume-area scaling approach indicates that this is a suitable method for estimating glacier wastage on a regional scale. Whilst the WATFLOOD results were similar to those from the hydrological-hypsometric approach regionally, there were considerable differences between the estimates of combined glacier wastage and Melt from different methods in the small, highly glacierised Peyto Glacier basin. The WATFLOOD results, and thus the estimates of Melt, are therefore treated with caution and it is proposed that glacier runoff data is collected with which to improve the model calibration, verify results and make uncertainty estimations, currently prevented by the severe lack of data on glaciers in the North and South Saskatchewan River basins. The results show that glacier wastage was smaller than Melt and varied between glaciers, though contributed over 10% to streamflow in a number of basins in the July to September period 1975-1998. Melt was positively correlated with basin glacier cover and contributed over 25% to streamflow from basins with glacier cover as little as 1% in the July to September period. The significance of Melt is manifest in its timing since it is equal to the annual volume of snow that accumulates into the glacier system, the volume of which melts as ice instead of snow thus entering the stream in the later summer months after snowmelt. Future glacier decline is therefore expected to result in an advancement of peak flow towards a snowmelt regime hydrograph, assuming that post glacial basin conditions do not similarly delay snowmelt runoff. The resulting reduced late summer flow, compounded by decreasing wastage contributions, is a concern for agricultural and industrial streamflow users, such as hydropower plants, and threatens ecological habitats. Downstream at Edmonton and Calgary, glacier wastage contributed approximately 3% of streamflow 1975-1998; however, Melt supplied over double this volume of flow thus the concern here is whether reservoir capacities are large enough to store a sufficient volume of the spring peak flow to meet supply needs in the late summer months of decreasing flows

Data handling methods and target detection results for multibeam and sidescan data collected as part of the search for SwissAir Flight 111

The crash of SwissAir Flight 111, off Nova Scotia in September 1998, triggered one of the largest seabed search surveys in Canadian history. The primary search tools used were sidescan sonars (both conventional and focussed types) and multibeam sonars. The processed search data needed to be distributed on a daily basis to other elements of the fleet for precise location of divers and other optical seabed search instruments (including laser linescan and ROV video). As a result of the glacial history of the region, many natural targets, similar in gross nature to aircraft debris were present. These included widespread linear bedrock outcrop patterns together with near ubiquitous glacial erratic boulders. Because of the severely broken-up nature of the remaining aircraft debris, sidescan imaging alone was often insufficient to unambiguously identify targets. The complementary attributes of higher resolution, but poorly located, sidescan imagery together with slightly lower resolution, but excellently navigated multibeam sonar proved to be one of critical factors in the success of the search. It proved necessary to rely heavily on the regional context of the seabed (provided by the multibeam sonar bathymetry and backscatter imagery) to separate natural geomorphic targets from anomalous anthropogenic debris. In order to confidently prove or disprove a potential target, the interpreter required simultaneous access to the full resolution sidescan data in the geographic context of the multibeam framework. Specific software tools had to be adapted or developed shipboard to provide this capability. Whilst developed specifically for this application, these survey tools can provide improved processing speed and confidence as part of more general mine hunting, hydrographic, engineering or scientific surveys

Optimizing Sound Speed Profiling for Hydrographic Surveys

The IHO Standards for Hydrographic Surveys (S-44) requires that hydrographic surveys account for sound speed uncertainties in order to determine the Total Propagated Uncertainty. If variations in sound speed are significant, the horizontal and vertical position of a sounding can vary by as much as several meters. Refraction artefacts can be typically dealt with in post-processing. This can be time consuming and require specialized processing expertise, especially in area of significant bathymetric relief and/or environmental variations in the water column. In this paper, we examine the application of recent advances in refraction based uncertainty to the ODIM Moving Vessel Profiler (MVP) controller software in order to optimize sound speed profiling operations.Las Normas de la OHI para Levantamientos Hidrográficos (S-44) requiere que los levantamientos hidrográficos tengan en cuenta la cuenta la incertidumbre sobre la velocidad del sonido con el objeto de determinar la Incertidumbre Total Propagada. Si las variaciones en la velocidad del sonido son significativas, la posición horizontal y vertical de una sonda puede variar tanto como varios metros. Típicamente se puede considerar los elementos refractarios durante el post procesado. Esto puede tomar tiempo y requerir experiencia especializada en procesamiento, especialmente en áreas de relieve batimétrico significativo y/o variaciones ambientales en la columna de agua. En este trabajo examinamos la aplicación de recientes progresos en la determinación de las incertidumbres basado en la refracción con el software de control del Perfilador del Movimiento de la Nave ODIM (MVP) con el objeto de optimizar las operaciones de perfilar la velocidad del sonido.Les normes de l’OHI pour les levés hydrographiques (S-44) exigent que les levés hydrographiques tiennent compte des incertitudes liées à la vitesse du son afin de déterminer l’incertitude totale propagée. Si les variations de la vitesse du son sont importantes, la position horizontale et verticale d’une sonde peut subir des variations de l’ordre de plusieurs mètres. D’une manière générale, les éléments de réfraction peuvent être pris en compte dans le cadre du post-traitement. Ceci peut prendre un certain temps et requiert des compétences spécialisées dans le traitement, notamment pour un relief bathymétrique significatif et/ou pour des variations environnementales dans la colonne d’eau. Dans cet article, nous examinons l’application des dernières avancées en matière d’incertitude basée sur la réfraction, au logiciel MVP (enregistreur de profils à partir d’un navire en mouvement) d’ODIM afin d’optimiser les opérations de détermination des profils de la vitesse du son

The Integration of the Free Fall Cone Penetrometer (FFCPT) with the Moving Vessel Profiler (MVP) for the Rapid Assessment of Seabed Characteristics

The Free-Fall Cone Penetrometer (FFCPT) is an instrument for the rapid assessment of seabed characteristics, such as grain size and shear strength. The FFCPT also acquires water column sound speed data during its descent to the seabed. The data collection process is very efficient when the FFCPT is deployed by an automated winch system, the Moving Vessel Profiler (MVP). This paper presents engineering, seabed, and SVP data that have been collected from a vessel moving at speeds from 4 to 8 knots.El Perfilador-Registrador Cônico de Calda Libre ( ‘Free-Fall Cone Penetrometer - FFCPT') es un instrumento que se usa para la râpida evaluaciôn de caractensticas del fondo marino, como el tamaho prédominante de los granos de los sedimentos y la resistencia al corte. El FFCPT adquiere también datos sobre la velocidad y la presiôn (SVP) de la columna de agua durante su descenso al fondo marino. El proceso de recogida de datos es muy eficaz cuando el FFCPT se despliega mediante un sistema de guinche automatizado, el Perfilador para Buque en Movimiento (‘Moving Vessel Profiler - MVP'). Este artîculo présenta datos de ingenieria, del fondo marino y de SVP, que han sido recogidos utilizando un FFCPT integrado a un MVP, a partir de un buque que navegaba a velocidades que oscilaban entre 4 y 8 nudos.Le pénétromètre à cône à chute libre (FFCPT) est un instrument d’évaluation rapide des caractéristiques des fonds marins, comme par exemple la dimension prédominante des grains des sédiments et la résistance du sol non drainé au cisaillement. Le FFCPT procède également à l'acquisition des données sur la vitesse du son et la pression (SVP) dans la colonne d'eau lors de sa descente vers le fond de la mer. Le processus de collecte des données est très efficace lorsque le FFCPT est utilisé avec un système de treuil automatisé, le profileur de bâtiment en mouvement (MVP). L’article qui suit traite de l’ingénierie, du fond de la mer et des données SVP qui ont été collectées à l'aide d'un pénétromètre FFCPT intégré dans un profileur MVP, à partir d’un bâtiment se déplaçant à des vitesses allant de 4 à 8 noeuds

Volatile Organic Compounds: Exposure and Mitigation In Colorado Nail Salons

Cancer risk estimates for Colorado nail salon workers were calculated based on 20 years of exposure to measured concentrations to benzene and formaldehyde, as well as cancer slope factors from the United States Environmental Protection Agency (US EPA) and anthropometric data from the Centers for Disease Control and Prevention (CDC). Cancer risk from formaldehyde exposure exceeded the US EPA de minimis risk level (1x10-6 ) for squamous cell carcinoma, nasopharyngeal cancer, Hodgkin&rsquo;s lymphoma, and leukemia; leukemia risk exceeded 1x10-4 in one salon. The average leukemia risk from benzene exposure also exceeded the US EPA de minimis risk level for all demographic categories modeled. Results from the nail salon short-term health and VOC exposure assessment found that 70% of surveyed workers reported experiencing at least one health issue related to their employment, with 40% reporting multiple related symptoms. Indoor concentrations of formaldehyde ranged from 5.32 to 20.6 ugm-3, across all 6 salons. Indoor concentrations of toluene ranged from 26.7 to 816 ugm-3, followed by benzene (3.13 to 51.8 ugm-3), xylenes (5.16 to 34.6 ugm-3), and ethylbenzene (1.65 to 9.52 ugm-3). Formaldehyde levels measured in one salon exceeded the Recommended Exposure Limit from the National Institute for Occupational Safety and Health (NIOSH) of 19.7 ugm-3. Concentrations of aromatic compounds measured were comparable to those measured in previous studies of occupational VOC exposure among oil refinery and auto garage workers. Cancer risk estimates for Colorado nail salon workers were calculated based on 20 years of exposure to measured concentrations to benzene and formaldehyde, as well as cancer slope factors from the United States Environmental Protection Agency (US EPA) and anthropometric data from the Centers for Disease Control and Prevention (CDC). Cancer risk from formaldehyde exposure exceeded the US EPA de minimis risk level (1x10-6) for squamous cell carcinoma, nasopharyngeal cancer, Hodgkin&rsquo;s lymphoma, and leukemia; leukemia risk exceeded 1x10-4 in one salon. The average leukemia risk from benzene exposure also exceeded the US EPA de minimis risk level for all demographic categories modeled. Results from nail product characterization showed that nail polishes were 56.3 to 61.5% VOC content by mass, with an average estimated emission rate of 2.3-2.4 mg mL-1 min-1 over 250 min. Acetone-based nail polish remover contained 100% VOC content by mass and an average estimated emission rate of 20 mg mL-1&nbsp;min-1&nbsp;over 40 minutes. Non-acetone-based nail polish remover contained 26.5% VOC content by mass and an average estimated emission rate of 6.6 mg mL-1&nbsp;min-1 over 40 minutes. Removal of VOCs emitted by nail products was studied in a controlled environment using adsorbent materials including coco coir (CC), wood-based biochar (BC), and commercial activate carbon (AC). All 3 low-cost adsorbents were found to remove VOCs from acetone-based nail polish remover over the course of 22.5 hours under both passive and active flow conditions. Passive VOC adsorption rates for fine grain CC, BC, and AC at concentrations of acetone &lt; 120 mgm-3&nbsp;ranged from 0.0005 to 0.0030 mg g-1 min-1, 0.0006 to 0.0052 mg g-1&nbsp;min-1, and 0.0009 to 0.0056 mg g-1&nbsp;min-1, respectively. Active flow conditions, generated using a synthetic jet actuator (SJA), were found to enhance VOC adsorption rates (up to a 100% increase in the first 2 h) in materials with smaller BET pore width (AC and BC) and decrease VOC adsorption rates for materials with larger BET pore width (CC). Adsorption rates were shown to be represented by a general nth-order rate equation that used ambient VOC concentrations and the mass of VOCs adsorbed as fitting parameters. Novel, low-cost sorbent sinks (air-cleaning art) were designed and constructed by embedding fine grain AC into common gypsum plaster; prototypes were then tested under controlled conditions in a closed chamber with acetone as the sorbate. Controlled testing showed that the air-cleaning art material can remove VOCs from nail salon products under both passive and active-flow conditions. In situ thermal regeneration of the sinks was also tested with an embedded resistance heating element. Testing showed that flow conditions and external surface area were the most important optimization parameters for increasing the VOC removal rate of the material. Regeneration experiments were inconclusive but suggest possible irreversibilities in the sorption process. A mathematical model was developed to predict the effects of both raw adsorbent materials and air-cleaning art in a typical nail salon, using time-resolved total VOC (TVOC) concentration data from the pilot VOC exposure study as the input. Model results were positive, showing that raw adsorbents and air-cleaning art could have a significant beneficial impact on VOC concentrations in the nail salon environment. The use of SJAs to generate active flow across the surface of the adsorbents was shown to enhance removal for raw AC and BC, as well as all of the air-cleaning art samples tested. Effective ventilation rates for fine AC ranged from 29.3 m3 h-1 (0.02 ACH), for 10 kg of fine AC under passive flow conditions, to 292 m3&nbsp;h-1&nbsp;(0.21 ACH) for 250 kg under active flow conditions, while air-cleaning art provided 3.32-9.03 mg m-2 h-1.</p

Arterio-Venous Fistula : Is it Critical for Prolonged Survival in the over 80's Starting Haemodialysis?

BACKGROUND: Dialysis in elderly patients (>80-years-old) carries a poor prognosis, but little is known about the most effective vascular access method in this age group. An arteriovenous fistula (AVF) is both time-consuming and initially expensive, requiring surgical insertion. A central venous catheter (CVC) is initially a cheaper alternative, but carries a higher risk of infection. We examined whether vascular access affected 1-year and 2-year mortality in elderly patients commencing haemodialysis. METHODS: Initial vascular access, demographic and survival data for elective haemodialysis patients >80-years was collated using regional databases. A cohort of conservatively managed patients was included for comparison. A log-rank test was used to compare survival between groups and a chi-square test was used to compare 1-year and 2-year survival. RESULTS: 167 patients (61% male) were included: CVC (101), AVF (25) and conservative management (41). Mean age (median) of starting haemodialysis (eGFR ≤10mL/min/1.73m2): CVC; 83.4 (2.3) and AVF; 82.3 (1.8). Mean age of conservatively managed patients reaching an eGFR ≤10mL/min/1.73m2 was 85.8 (3.6). Mean (median) survival on dialysis was 2.2 (1.8) years for AVF patients, 2.1 (1.2) for CVC patients, and 1.5 (0.9) for conservatively managed patients (p = 0.107, controlling for age/sex p = 0.519). 1-year and 2-year mortality: AVF (28%/52%); CVC (49%/57%), and conservative management (54%/68%). There was no significant difference between the groups at 1-year (p = 0.108) or 2-years (p = 0.355). CONCLUSION: These results suggest that there is no significant survival benefit over a 2-year period when comparing vascular access methods. In comparison to conservative management, survival benefit was marginal. The decision of whether and how (choice of their vascular access method) to dialysis the over 80s is multifaceted and requires a tailored, multidisciplinary approach

Arterio-Venous Fistula : Is it Critical for Prolonged Survival in the over 80's Starting Haemodialysis?

BACKGROUND: Dialysis in elderly patients (>80-years-old) carries a poor prognosis, but little is known about the most effective vascular access method in this age group. An arteriovenous fistula (AVF) is both time-consuming and initially expensive, requiring surgical insertion. A central venous catheter (CVC) is initially a cheaper alternative, but carries a higher risk of infection. We examined whether vascular access affected 1-year and 2-year mortality in elderly patients commencing haemodialysis. METHODS: Initial vascular access, demographic and survival data for elective haemodialysis patients >80-years was collated using regional databases. A cohort of conservatively managed patients was included for comparison. A log-rank test was used to compare survival between groups and a chi-square test was used to compare 1-year and 2-year survival. RESULTS: 167 patients (61% male) were included: CVC (101), AVF (25) and conservative management (41). Mean age (median) of starting haemodialysis (eGFR ≤10mL/min/1.73m2): CVC; 83.4 (2.3) and AVF; 82.3 (1.8). Mean age of conservatively managed patients reaching an eGFR ≤10mL/min/1.73m2 was 85.8 (3.6). Mean (median) survival on dialysis was 2.2 (1.8) years for AVF patients, 2.1 (1.2) for CVC patients, and 1.5 (0.9) for conservatively managed patients (p = 0.107, controlling for age/sex p = 0.519). 1-year and 2-year mortality: AVF (28%/52%); CVC (49%/57%), and conservative management (54%/68%). There was no significant difference between the groups at 1-year (p = 0.108) or 2-years (p = 0.355). CONCLUSION: These results suggest that there is no significant survival benefit over a 2-year period when comparing vascular access methods. In comparison to conservative management, survival benefit was marginal. The decision of whether and how (choice of their vascular access method) to dialysis the over 80s is multifaceted and requires a tailored, multidisciplinary approach

Drexel racing senior design 2003 project proposal: engine analysis and optimization team

Drexel University has competed in the Formula SAE competition for almost ten years with the support of the students who have designed and built racecars and all support systems. An extensive variety of engines including single cylinders, four cylinders, carbureted, fuel injected, forced induction, and naturally aspirated engines have been used in past years. Most recently a racecar based on the Honda CBR600F4i engine has been used. This engine has the following specifications: 600cc, four cylinders, fuel injection, and a dual overhead cam. The Drexel Formula SAE team tailors the engine to meet the rules of competition (See Appendix A: “Relevant Rules of Competition”). The four members of our team comprise the SAE Engine Optimization Team. We will design an intake and exhaust track with the specific goal of maximizing performance through the following three judged categories: static inspection and engineering design, solo performance trails, and high-performance track endurance. The racecars performance is dependant upon the safety, suspension, chassis, drive train, intake and exhaust systems. Our team will be focusing on the design, fabrication, and manufacturing of the intake and exhaust systems. The intake will be broken down into a three-part system: 1) throttle body, 2) plenum, and 3) intake runners. The exhaust will be considered as a two-part system consisting of: 1) exhaust headers, 2) silencer. We will pay careful attention to conform to the 2004 formula SAE rules, and hope to surpass competition in the solo performance trails and the highperformance track endurance events

Drexel racing senior design 2003 project proposal: engine analysis and optimization team

Drexel University has competed in the Formula SAE competition for almost ten years with the support of the students who have designed and built racecars and all support systems. An extensive variety of engines including single cylinders, four cylinders, carbureted, fuel injected, forced induction, and naturally aspirated engines have been used in past years. Most recently a racecar based on the Honda CBR600F4i engine has been used. This engine has the following specifications: 600cc, four cylinders, fuel injection, and a dual overhead cam. The Drexel Formula SAE team tailors the engine to meet the rules of competition (See Appendix A: “Relevant Rules of Competition”). The four members of our team comprise the SAE Engine Optimization Team. We will design an intake and exhaust track with the specific goal of maximizing performance through the following three judged categories: static inspection and engineering design, solo performance trails, and high-performance track endurance. The racecars performance is dependant upon the safety, suspension, chassis, drive train, intake and exhaust systems. Our team will be focusing on the design, fabrication, and manufacturing of the intake and exhaust systems. The intake will be broken down into a three-part system: 1) throttle body, 2) plenum, and 3) intake runners. The exhaust will be considered as a two-part system consisting of: 1) exhaust headers, 2) silencer. We will pay careful attention to conform to the 2004 formula SAE rules, and hope to surpass competition in the solo performance trails and the highperformance track endurance events