bluuebunny/crossref_metadata_2025 huggingface dataset:
Trace Metal Levels in Nearshore Sediments Close to Industrial Discharges off Cuddalore (Bay of Bengal)
Authors: Joseph T , Balachandran KK , Nair M , Kesavadas V , Nair KKC , Paimpillil JS
Published: April 2008

Trace metals in the sediment and in the overlying water column along with texture characteristics in the vicinity of industrial discharges at Cuddallore were analyzed, covering the seasonal changes to identify probable anthropogenic influence on this coast. During monsoon, cadmium and zinc had insignificant correlation with other trace metals. Other metals, except Mn, had a positive significant correlation. The spatial distribution of metals and the correlation were drastically changed during post-monsoon, loosing significant correlation for Pb, Ni, and Mn with other metals and the observed correlations being mostly negative. Cobalt and copper had strong positive correlation with all metals. Among the trace metals in water column Cu and Ni had strong positive correlation (0.88). Most of the correlation was positive except for Fe and Ni. During post-monsoon, levels of Cd, Co, Cu, Pb, Zn, and Mn had dropped down to 33–94%. The maximum amount of lowering was noticed for Pb and Cu. Ni (148%) and iron (110%) levels had an increasing trend. The trace metals in the water column had a similar decreasing trend (41–76%) for Cu, Ni, Fe and Zn. Cluster analysis had shown three distinct clusters of sampling points and was classified as least (4 stations), moderate (5 stations) and high (5 stations) trace metal contaminated regions. The least contaminated stations were all in the offshore area. Wilks lambda (0.027) denoted the good discriminatory power of the current model with the three groups. Partial lambdas indicated that Cr contributed the most, Cd the second most, Ni the third most and Mn contributed the least for the overall discrimination. The other trace metals also contribute to this function, but with negative sign. The forcing mechanisms behind the rapid changes in trace metal levels; their spatial distribution patterns and correlation strengths were indicated.
Study of the Geochemical Distribution of Heavy Metals in Sediments in Areas Impacted by Coal Mining
Authors: Teixeira EC , Rodrigues MLK , Alves MFC , Barbosa JR
Published: April 2008

This study evaluated the geochemical distribution and potential mobility of heavy metals in sediments impacted by coal extraction in the Candiota Region of Brazil. Sampling was performed in Candiota stream and tributaries, at eleven sites, in February and June 2000. The silt/clay fraction of sediments was analyzed by total and sequential extraction schemes established by the EPA and European Commission, respectively. The results indicated higher mobility for manganese, intermediary for nickel, zinc, copper, and lower for iron, chromium, and aluminum. The mouth of Poacá Stream, most affected by mining activities, presented an increase of iron in the oxidizable fraction, as well as zinc, nickel, and copper, suggesting association with sulfides and presence of pyrite in the sediments. The same behavior was observed in the Candiota Stream, after the entrance of the Poacá. Due to a lower pH (4.3) caused by mining acid drainage, at the mouth of Poacá Stream, manganese content decreased in sediments and increased ten times in the water column.
Characterization of a Catastrophic Flood Sediment Layer: Geological, Geotechnical, Biological, and Geochemical Signatures
Authors: Tremblay H , Desrosiers G , Locat J , Mucci A , Pelletier É
Published: April 2008

In 1996, an important rainstorm took place in the Saguenay region, Canada, that caused severe flooding and erosion of a large amount of post-glacial sedimentary material. Consequently, about 20 million tons of sediment were deposited in the upstream part of the Saguenay Fjord, covering the recent, contaminated sediments with a 10 to 60 cm thick layer of relatively clean material. This flood layer was distinguished from the pre-flood sediments by various properties: low consistency and low resistance, high water content, the absence of benthic organisms, or the presence of inherited geochemical components. In this study, we evaluated the criteria used by the various investigators to identify the 1996 flood deposit, then finally compared its signature. Subsequently, we assessed the spatial variability of the deposit and its effect on the interpretation of temporal studies.
In situ Flume Measurements of Sediment Erodability in Saguenay Fjord (Quebec, Canada)
Authors: Moreau AL , Locat J , Hill P , Long B , Ouellet Y
Published: April 2008

The erodability of surficial sediment in Saguenay Fjord, Quebec, was investigated over a three-year period at fourteen sites in Baie des Ha! Ha! and the North Arm using a benthic flume, Miniflume. Previous studies showed that Saguenay Fjord sediment characteristics vary greatly on small and large scales. The critical shear stress (τc) reflect this variability, with τc between 0.07 and 0.48 Pa. The measured critical shear stress and erosion rates were consistent with those of other in situ studies in other areas. The variability in the results is linked to the great spatial variability of benthic sediments rather than to temporal variability. Some of the results were integrated in the Parchure and Mehta (1985) erosion law since the upper portion of the active sediment layer is typically a stratified bed. The identification of erosion parameters (critical shear stress, erosion rate, parameters α and Ef in erosion law) and their high variability is the first step in defining the erosion susceptibility hazard in Saguenay Fjord.
Factors Controlling Contaminant Transport Through the Flood Sediments of the Saguenay Fjord: Numerical Sensitivity Analysis
Authors: Dueri S , Therrien R
Published: April 2008

In July 1996, two days of intense rainfall caused severe flooding in the Saguenay region and led to the discharge by rivers of several million cubic meters of clean sediments to the Fjord. This turbidite layer, composed of clean sediments, represents a potential barrier for the migration of heavy metals and PAHs from the underlying contaminated sediments towards the new sediment-water interface. A numerical model has been developed to simulate the vertical migration and remobilization of dissolved contaminants in the capping layer. The model includes the main physical, chemical and biological factors affecting the contaminant flux in the cap. Calibration of the model has been achieved through comparison with the data collected during the field and laboratory characterization of the sediments of the Saguenay Fjord. A detailed sensitivity analysis, based on factorial design, shows that the model parameters associated with bio-irrigation have the greatest impact on the model output and by extension on the effectiveness of a capping layer.
Rehabilitation of Brine-Saturated Sediments
Authors: Haug MD , Barbour SL , Johns CA
Published: April 2008

A large quantity of brine-saturated fine-grained sediments (insolubles) is produced each year as a by-product of potash mining. These sediments have traditionally been disposed of in clay-lined ponds to minimize their environmental impact. Many of these ponds are now nearing capacity and there is a desire to find techniques to wash the brine from these sediments so they can be taken outside the waste management areas and used for other purposes. Laboratory studies have shown that brine can be removed from these insolubles by flushing with fresh water; however, the feasibility of de-brining by this method had not been established at field scale. As a result, a field study of three prototype de-brining systems was conducted at the Potash Corporation of Saskatchewan Inc. (PCS) Allan Potash mine. The three treatment systems investigated were: a gravity drainage pond, a reverse-flushing pond with a sand and gravel filter, and a reverse-flushing pond with a geotextile filter.
Sediment Transport and Deposition Processes Near Ocean Outfalls in Southern California
Authors: Lee HJ , Noble MA , Xu J
Published: April 2008

An urbanized coastal ocean that has complex topography and large-scale atmospheric and océanographic forcing can contain a variety of sediment and pollutant distribution patterns. For example, the central southern California Bight has two large embayments, Santa Monica and San Pedro Bays, that are connected by a short, very narrow shelf off the Palos Verdes peninsula. The complex topography causes quite different ocanographic and sediment distribution patterns in this fairly small region of the coastal ocean. In addition, three sewage outfalls discharge material over the outer shelf. A large suite of sediment cores was obtained and analyzed for contaminants, physical properties, accumulation rates, and grain sizes. Arrays of instrumented moorings that monitor currents, waves, water clarity, water density and collect resuspended materials were deployed. The data and models developed for the Palos Verdes margin suggest that a large reservoir of DDT and its byproducts exists in the coastal ocean sediment and will continue to be exhumed and transported along the shelf for a long time. On the Santa Monica shelf, very large internal waves, or bores, are generated at the shelf break. The near-bottom currents associated with these waves sweep sediment and the associated contaminants from the shelf onto the continental slope. On the San Pedro margin an initial examination of recent data collected in the coastal ocean does not suggest that bacterial contamination on local beaches is primarily caused by transport of material from the adjacent ocean outfall.
Numerical Modeling of Hydrodynamic Circulation and Cohesive Sediment Transport in Hartwell Lake, South Carolina/Georgia, USA
Authors: Elçi Ş , Work PA
Published: April 2008

This paper describes numerical modeling of hydrodynamic circulation and cohesive sediment transport in Hartwell Lake, South Carolina/Georgia, a U.S. Army Corps of Engineers (USACE) hydropower and flood control reservoir. A U.S. Environmental Protection Agency (EPA) “Superfund” site is located on a tributary to the lake because of high concentrations of polychlorinated biphenyls (PCBs) in the lake sediments. The primary objective of this study involves prediction of depositional zones for sediments transported within the reservoir.

The EFDC (Environmental Fluid Dynamics Code) model developed by Hamrick (1996) is used to describe lake hydrodynamics and sediment fate. Historical records of wind and flow were used to determine frequencies of occurrence and representative conditions for prediction of long-term deposition zones for sediment transported by the flow.

Sensitivity of hydrodynamic processes to model parameters were investigated and wind was found to be the major force driving the circulation. Model results for cases with realistic long-term forcing indicated likely zones of sediment deposition, useful for mitigation of pollution problems as well as predictions of reservoir lifetime and development of maintenance schemes.
Review of Pneumatic Impact Sensitivity Data Obtained on Selected Polymers for Aerospace Applications
Authors: Hirsch D , Peyton G , Hshieh F-Y , Beeson H
Published: April 2008

NASA started evaluating compatibility of polymers with oxygen more than 30 years ago. New test methods and a systematic approach to evaluate oxygen system hazards were developed. The new methods were used extensively to acquire data on a large number of polymers. NASA's batch-lot control strategy for qualifying spacecraft materials allowed acquiring extensive data, principally on the best candidates for aerospace usage. A review of pneumatic impact sensitivity data on selected materials for aerospace applications is provided; it includes data on polytetrafluoroethylene, Viton®5 A, polychlorotrifluoroethylene, Vespel®6 SP-21 and Vespel SP-1. Since the number of samples tested at each condition was large, the data are presented in terms of reaction frequencies. This is considered to be statistically defensible when compared with the uncertainties related to the pressure threshold data commonly reported. For most materials, the data presented were obtained from a large number of batches, thus minimizing potential bias caused by batch-to-batch variability.
Combustion Products Toxicity of Non-Metallic Materials Used for Medical Oxygen Equipment
Authors: Barthélémy H
Published: April 2008

Non-metallic materials (plastics, elastomers and lubricants) are known to be the most critical materials in high-pressure oxygen applications. Such materials are typically found in valves (seats and stem seals), regulators (diaphragms and seats), and plastic-lined flexible hoses. The risk of ignition has been well known for many years, but more recently it was determined that toxic gases can be generated by the ignition or decomposition of some non-metallic materials. This risk shall of course be assessed for medical oxygen and any breathing gas application. New international standards, currently in preparation, recommend how to address this toxicity risk. In this paper, the toxicity risk related to the use of some non-metallic materials is reviewed. A test method to determine the potential toxic gases, which could be generated by combustion or decomposition is described. Results from the analysis of toxic gases are presented. Finally, we make practical recommendations to avoid this toxicity risk.
Determining the Time Required for Materials Exposed to Liquid Oxygen to return to Normal Air Ignitability by Mechanical Impact
Authors: Smith SR , Stoltzfus JM
Published: April 2008

Catastrophic fires due to liquid oxygen (LOX) spills have occurred in the aerospace, oxygen production, transportation, distribution, and user sectors of industry as well as in the medical community. One contributing factor is that materials exposed to a LOX spill can become impact sensitive. Knowledge of the length of time necessary for common construction and clothing materials to return to normal air impact sensitivity after exposure to liquid oxygen is an important factor in avoiding these fires. Four different mechanical impact tests were performed on materials that could be exposed to a liquid oxygen spill. The materials tested were cotton muslin, floor tile with adhesive, leather, butyl rubber, industrial carpet, cork, and asphalt. The first test determined if each material was ignitable by mechanical impact in air. The second test determined the baseline energy required to ignite each material in LOX. The third and fourth tests determined the amount of time each LOX-soaked material required to return to normal air mechanical impact ignitability with an ambient-temperature test system and with a chilled test system. This paper presents the test results and a discussion.
Ultrasonic Measurement Technique of Burning Metals in Normal and Reduced Gravity
Authors: Chiffoleau GJA , Steinberg TA , Veidt M
Published: April 2008

The in situ real time measurement of the regression rate of a melting interface (RRMI) is performed by the ultrasonic measurement system reported here. The RRMI is the rate at which a solid/liquid interface (SLI) moves along a metallic rod while burning in an oxygen-enriched atmosphere and is an important flatnmability indicator. The ultrasonic transducer and associated equipment used to drive the transducer and record the echo signal is described, along with the process that transforms the acquired signals into a RRMI value. Test rods of various metals and geometric shapes were burned at several test conditions in different test facilities. The RRMI results with quantified errors are presented and reviewed. The effect of reduced gravity on burning metals is important to space-applications and RRMI results obtained in a reduced gravity environment are also presented.
Promoted Ignition-Combustion Tests with Structured Aluminum Packings in Gaseous Oxygen with Argon or Nitrogen Dilution at 0.1 and 0.6 MPa
Authors: Meilinger M
Published: April 2008

High-surface-area aluminum structured packings are finding a wide use in the cryogenic distillation of air. An experimental program was performed to determine the oxygen compatibility of commercial packings. In particular, the influence of pressure increase up to 0.6 MPa (6 bar absolute) and the effect of the replacement of nitrogen by argon as O2-diluting gas were investigated. Additionally, the impact of reducing the sheet thickness from 0.2 mm to 0.1 mm was tested.

The packing samples weighing 120–250 g were ignited on top by a 3 g thermite pill, resulting in a combustion channel which was either contained within the sample or passed through it. Incidents causing a noticeable downward widening of the channels were evaluated as “promoted combustion.” Typically, a promoted combustion occurred when the weight loss of corrugated sheet exceeded 10%.

The increase of pressure reduces the O2-threshold concentration for propagated combustion, as expected. Reducing the thickness of the sheets from 0.2 mm to 0.1 mm affects the O2-threshold concentration only slightly. A replacement of N2 by Ar as O2-diluting gas at 0.6 MPa shifts the O2-threshold somewhat beyond accuracy, but the extent of combustion in O2/N2-mixtures is much more substantial than in O2/Ar-mixtures. Thus a complete destruction of the Al-samples is reached in O2/N2-mixtures at much lower O2-concentrations.
Microanalysis of Quenched and Self-extinguished Aluminum Rods Burned in Oxygen
Authors: Osborne BP , Suvorovs T , Wit JD , Steinberg TA
Published: April 2008

Promoted ignition tests and quench tests have been conducted and analysed for 3.2 mm aluminum rods in 99.995% oxygen. Tests have been conducted in oxygen pressures varying from 538 kPa to 773 kPa. Samples that self-extinguished or were quenched were selected for further analysis. The microstructure of the selected samples were analysed by electron microscopy, using energy dispersive spectrometry and electron back-scatter techniques, to identify and visualize, respectively, the species present. The grain structures of these samples were etched, viewed and photographed under polarized light by an optical microscope. From the micrographs produced by the post-test analysis, clearly defined boundaries between the oxide and the melted and resolidified metal have been observed. In both the melted and resolidified metal and the oxide layer, significant numbers of gas bubbles, solid inclusions and several diffuse oxide bubbles have been captured during the cooling process. It is concluded that convective movement is occurring within the molten drop and that analysis of quenched samples provides more useful information on the state of the burning droplet than samples allowed to cool slowly to room temperature. Recommendations are made regarding future investigations into aluminum burning, focusing on the transport of reactants through the liquid oxide layer.
Promoted Ignition-Combustion Behavior of Tubular Aluminum Samples in Liquid and Gaseous Oxygen Environments
Authors: Million JF , Zawierucha R , Samant AV
Published: April 2008

Past literature has reported on the occurrence of violent energy releases (VER) involving either high surface area aluminum structured packing or brazed aluminum heat exchanger (BAHX) samples subjected to promoted ignition-combustion testing in liquid oxygen (LOX) environments. In each of these situations, both the aluminum packing samples and the BAHX specimens contained relatively thin sections of aluminum. The aluminum thickness ranged from 0.2 to 0.25 mm for the aluminum packing and the fin portion of “thin fin” BAHXs. Other “thick fin” BAHXs tested had nominal fin thicknesses ranging from 0.41 mm to 0.46 mm. Similar flammability data have not been reported for thick wall (4.1 mm), 3003 tubular aluminum heat exchanger material which may be used in LOX applications. The impetus for this program was to study the promoted-ignition combustion behavior of thick wall, tubular aluminum samples in various LOX environments using both a localized hydrocarbon promoter and uniformly dispersed hydrocarbon film. Tests were also conducted in various gaseous oxygen (GOX) environments using uniformly dispersed hydrocarbon films.

Promoted ignition-combustion tests were conducted on 4.1 mm thick aluminum ubes in LOX at pressures ranging from 101 kPa (0 psig) to 3551 kPa (500 psig). Tests in GOX were also conducted at 170 kPa (10 psig) and 274 kPa (25 psig). The resultant flammability characteristics of the aluminum tube specimens are compared to previously studied BAHX samples since both may be used in LOX applications.
Using ASTM Standard Guide G 88 To Identify and Rank System-Level Hazards in Large-Scale Oxygen Systems
Authors: Forsyth ET , Newton BE , Rantala J , Hirschfeld T
Published: April 2008

Performing hazards analyses and fire risk assessments on oxygen systems is critical to ensure that a system design has a low probability of ignition and a low consequence of ignition. Historically several different methods have been used to identify and evaluate fire hazards in oxygen systems. Most of these methods, however, are designed for detailed materials or component analyses, and can be impractical for large-scale oxygen systems with many components and even multiple end processes. Wendell Hull & Associates, Inc. (WHA), in conjunction with Oxygen Safety Consultants, Inc. and INCO Ltd., has developed an efficient approach to identify and evaluate hazards in large-scale oxygen systems. The WHA oxygen hazards and fire risk assessment process considers the important aspects of oxygen system safety as they relate to design, cleaning, operations and maintenance, and uses ASTM Standard Guide G 88 as a basis for quickly identifying and ranking system-level oxygen hazards. ASTM G 88 is a standard guide for oxygen system design containing many system-level factors known to contribute to ignition and propagation of fires. The WHA analysis process applies ASTM G 88 at the system level, using both schematic analysis and visual inspection to systematically assign a hazard severity ranking to all system components, allowing components that possess the greatest risk of ignition and fire propagation to be quickly identified and further evaluated. This paper describes the WHA oxygen hazards and risk assessment method, using ASTM G 88 to quickly identify and assign a hazards severity ranking to components in large-scale oxygen systems.
Oxygen Hazards Analysis of Space Shuttle External Tank Gaseous Oxygen Pressurization System
Authors: Shoffstall MS , Stoltzfus JM
Published: April 2008

In November 1999, White Sands Test Facility (WSTF) was informed of damage to a space shuttle oxygen system component that could release small metal particles into the gaseous oxygen (GOX) pressurization ystem of the external tank (ET). The WSTF oxygen hazards analysis group was requested by the NASA Johnson Space Center Propulsion and Fluids Systems Branch to evaluate the possible particle impact ignition hazards in the ET GOX pressurization system.

The ET GOX pressurization system uses high pressure bled from the oxygen urbopumps to provide ullage pressure for the liquid oxygen (LOX) tank. GOX enters the LOX tank through a diffuser attached to the interior of the LOX tank. The calculated GOX velocity at the diffuser outlet screen was approximately 51 m/s. According to published particle impact data, ignition often occurs at velocities of 45 m/s [1]. Therefore, NASA would have to either fly with a legitimate particle impact ignition risk or dismantle and clean the entire ET pressurization system before a subsequent flight.

Fortunately, WSTF located previously unpublished particle impact data that indicated the particulate potentially trapped in the ET pressurization system did not pose a legitimate ignition hazard. Based on these data, WSTF was able to assure JSC that there was not a legitimate particle impact ignition risk in this case. Therefore, this shuttle mission was safely accomplished without the delay or costs associated with disassembling the entire ET pressurization system.

In addition to presenting the rationale used to safely proceed with the shuttle mission, this paper also presents the previously unpublished data used to make these decisions.
Cause And Origin Analyses Of Two Large Industrial Oxygen Valve Fires
Authors: Newton B , Forsyth ET
Published: April 2008

Two recent fires were investigated in industrial gas oxygen delivery systems that resulted in significant facility damage as well as personnel injury and death. One fire developed in a 6-in. ball valve being utilized as an isolation valve. This fire was kindled while the valve was being opened under a low-pressure differential and resulted in extensive burnout and significant facility destruction. The other fire developed in a 12-in. butterfly valve being utilized as a pipeline isolation and pressurization control valve downstream of an oxygen boost compressor. The valve utilized generally good materials but was vulnerable to ignition and sustained propagation probably due to the presence of an unusual kindling chain. This paper reviews the investigations and analytical work performed during the accident reconstructions and highlights the “lessons learned” from the incidents.
Pipe Cleaning Using HFE Solvents and Assessment of Particle Contamination Found During Pipe Connection
Authors: Fletcher LE , Zugno R , Dimas J
Published: April 2008

A pipe cleaning rig that flushes HFE™ solvents through pipes using a series of pressure vessels was developed and tested to determine whether the solvents and the equipment could clean aircraft oxygen system piping to the RAAF's specifications. The first aircraft pipes tested were 1/8 in. copper with either brass dome or cone-shaped end-fittings. To achieve 0.09 m2 (1 sq ft) of internal surface area, over 9 meters of pipe was required.

Results showed that HFE-7100™ was sufficient to remove most oils and greases, but one 600 mL flush with HFE-71DE™ was required to remove OM-15 hydraulic oil. However, initial particulate analysis showed the procedure did not meet the required particle specification. The reason was identified as particle contamination caused by the reconnection of pipes during the verification process. Once the verification method was modified to eliminate further connections, the particle specification was achieved.

This particle contamination was investigated further because this would occur during installation of these pipes in aircraft. The number of particles contaminating the wetted area was found to vary linearly with the number of reconnections, and between different fitting designs.
Intimidation in Ice Hockey: An Exploratory Assessment
Authors: Crawford BJ , Stuart MJ , Smith AM , Brennan RD
Published: April 2008

The purpose of this investigation was to examine the components of intimidation in ice hockey and to determine their effects on players, coaches, and referees. In a pilot test, hockey coaches (N = 17) from three levels of participation were invited to an informal, exploratory symposium to assess their opinions on the role of intimidation in ice hockey. The following themes emerged: a) coaches' behavior and expectations, b) observable behavior, c) player's perceived role, and d) sociological factors. A preliminary intimidation model was developed. A survey including 80 open- ended questionnaires designed to stimulate discussion on the definition of intimidation, methods used to intimidate, and factors perceived as intimidating, was distributed to players (N = 66), coaches (N = 8), and referees (N = 6). The data were analyzed using qualitative methods [1,2] and intimidation was defined. Results support a theoretical model, which serves as a point of departure for future research and visually depicts the components of intimidation and their interactions.
The Power of the Denominator: A Proposal for More Comprehensive Modeling of Risk Factors in Ice Hockey Injuries
Authors: Stuart MJ , Smith AM , Larson DR
Published: April 2008

In the sport of ice hockey, the incidence of injury has been investigated at multiple levels of participation based on collective player exposure, which assumes equal playing time among participants. However, playing time varies enormously between individual players on a given team due to variability in the number and length of shifts. Individual player monitoring, although labor intensive, more accurately identifies risk factors for sustaining injuries. Specific player exposure data are necessary for detailed analysis of factors such as style of play, illegal activities, equipment, player size, and officiating. In addition, prospective, uniform and accurate collection of exposure data may permit meaningful comparison of injury rates between levels of participation in ice hockey and also among different sports. Refinement of data collection tools that determine individual player injury exposure will increase the power of the denominator and facilitate prevention of ice hockey injuries.
Communities of Practice as an Approach to Foster Ice Hockey Coach Development
Authors: Trudel P , Gilbert WD
Published: April 2008

Literature on youth ice hockey indicates that there is a need for changes so children can play a safer game in a more fair-play environment. Throughout this paper we argue that with the existing training programs for coaches and the others involved in youth ice hockey it will be difficult to move in that direction. The adoption of values like integrity, respect, and fairness is dependent upon recognizing the importance of providing a context where participants can negotiate the meaning of these concepts and how they should be implemented. In this perspective, learning is defined as an exchange of views as opposed to the traditional perspective where learning is the result of teaching. Based on Wenger's conceptual framework, when a group of people share a joint enterprise and deepen their knowledge and expertise in this area by interacting on an ongoing basis we see the emergence of a Community of Practice. The important role that communities of practice can play has been demonstrated in many areas such as education and business.
Responsibilities, and Liabilities for Coaches, Officials, and Leagues with Respect to Safety in Ice Hockey
Authors: Granger MS , Augeri A , Pelletier A
Published: April 2008

This paper seeks to examine new areas of liability for those involved in amateur ice hockey. By exploring recent litigation and programs designed to decrease risk of injury, and consequent liability, this article summarizes key issues affecting coaches, officials and league administrators in the new millennium.
Creatine Supplementation in Ice Hockey: A Review of Applicability and Safety
Authors: Juhn MS
Published: April 2008

Creatine remains a popular supplement due to its legality and record of relative safety. Its ergogenic potential lies in the enhanced utilization of phosphocreatine (PCr) to generate ATP anaerobically, and possibly accelerated resynthesis of PCr during rest periods between heavy bouts of exercise. Its effectiveness as an ergogenic aid remains controversial, since most studies with favorable results have been on stationary cycles in laboratory settings, as opposed to “on the field” or “on the ice” performance. Furthermore, creatine's efficacy is limited to the anaerobic (all-out sprint) state, and sports such as ice hockey involve a combination of aerobic and anaerobic activity. Still, creatine supplementation may have applicability to ice hockey because players skate in shifts and do require anaerobic bursts of speed. The water weight gain which creatine causes may explain why studies on runners and swimmers have been unconvincing of an ergogenic effect, but this may be less of an issue in skaters. Short-term administration of creatine has been found to increase muscle compartment pressures in the leg, due to water retention. This is the likely explanation for the numerous reported complaints of muscle cramping. Gastrointestinal tolerability and renal overload are also areas of concern. Although creatine has not been found to cause serious side effects when consumed at recommended doses for 8 weeks or less, most subjects take creatine at much higher doses than recommended. Long-term safety is not established. Another concern with creatine, as with all supplements, is that it is not classified as a drug and therefore can bypass Food and Drug Administration (FDA) scrutiny for product claims of efficacy, safety, and purity.
Does a Bimolar Mouthguard Alter Ventilation of Hockey Players?
Authors: Montgomery DL , Stefik C , Delaney JS , Pearsall DJ , Turcotte RA
Published: April 2008

Athletes competing in contact sports commonly wear intra-oral dental mouthguards. Data are sparse concerning the influence of a mouthguard on breathing during exercise. We compared VE and VO2 during submaximal and maximal exercise on a skating treadmill (TM) while wearing an intra-oral dental mouthguard. Female varsity hockey players (n = 12) performed two skating tests on a TM with and without a mouthguard (WIPSS Jaw-Joint Protector). The players wore the mouthguard during hockey practices prior to collection of ventilation data on the treadmill. Also, the players completed a questionnaire that examined their perception of the mouthguard in terms of ventilation, comfort and performance. A 10-point rating scale was used for this evaluation. Two performance tests on the skating treadmill examined the effect of the mouthguard on submaximal and maximal aerobic exercise. The subjects skated for 4 min at 2 submaximal velocities (14 and 16 km h-1), separated by 5 min of passive recovery. A VO2max test followed the submaximal tests and commenced at 18 km h-1 with the velocity increasing by 1 km h-1 every minute until volitional fatigue. VE, VO2, VCO2 and RER were analyzed using a Sensor Medics 2900 metabolic cart. Ventilation was unchanged when skating at the two submaximal velocities. VC2max was 48.8 ml/kg.min using the intra-oral mouthguard and was 52.4 ml/kg.min without a mouthguard. VEmax was 108.5 L/min using the intra-oral mouthguard and was 114.1L/min without a mouthguard. The results showed that VEmax and VO2max were lower using the mouthguard compared to the no-mouthguard condition.
Psychophysiologic Factors and Performance in Ice Hockey Goalies During Competition
Authors: Smith AM , Finnie SB , Stuart MJ , Meis J , Beaver KM , Laskowski ER , Young WF
Published: April 2008

Studying goalies, who play a key position in hockey requires examining psychophysiologic variables and their relationship to performance during games when the outcome is important [15]. This investigation tested all three aspects of emotion (subjective, physiologic changes, and performance). Nine male goalies completed questionnaires and provided salivary cortisol before, during, and after each game. Heart rate (ECG signal) was integrated with the goalie's performance video. Goalies rated on Likert Scales; headaches, stomach aches, insomnia, nervousness, and awareness of heart pounding. Data from 16 games were obtained. Of nine, two goalies provided data on three games each; one goalie was classified as a responder and the other a non-responder, based on salivary cortisol levels (SCL). The responder's SCL increased 572% between baseline and post-period assessments, whereas SCL in the non-responder increased 50% above baseline. The responder's SCL increased 8 times baseline when he faced 16 shots in a period. The responder goalie's game heart rates (HRs) were 160,152, and 167 beats per minute (bpm) and the non-responder's HRs were 147, 132, and 142 bpm for three games. Game performance was similar for both goalies.
The Biomechanical Characteristics of Development-Age Hockey Players: Determining the Effects of Body Size on the Assessment of Skating Technique
Authors: McPherson MN , Wrigley A , Montelpare WJ
Published: April 2008

Skating ability, and more specifically the ability to accelerate from a stationary position or change direction rapidly, is recognized as one of the most important skills in ice hockey. While coaches may use drills to compare skating performance between individuals, especially during player selection, few studies have identified the essential kinematic variables that contribute to the ability of development-age hockey players to accelerate over a specified distance. Previous research reported that the determination of performance and ultimately skating power could be related to specific biomechanical parameters, especially among developing hockey players. However, there is evidence to suggest that the potential confounding effects of height and weight should be considered in such biomechanical evaluations. Considering the range of variability for the height and weight of ten year-old children, it may be appropriate to include these as predictors of skating performance.

The purpose of this study was to evaluate the biomechanical characteristics of minor hockey players while performing an on-ice acceleration skill test. In addition, the study evaluated the contribution of height and weight on the assessment of skating technique. Participants were 30 male development-age hockey players categorized by level of play. Correlation identified the kinematic variables related to time to skate six meters. Regression analysis identified the set of variables that best predicted time to skate six meters. Comparing structural models across studies demonstrates the importance of body size on skating performance. These results illustrate the importance from the development age, through to university athletes, to elite NHL prospects.
Bronchoscopic Lung Volume Reduction — A Novel Tissue Engineering Treatment for Advanced Emphysema
Authors: Ingenito EP , Tsai L , Berger RL , Hoffman A
Published: April 2008

Emphysema is a progressive, disabling pulmonary disease characterized by destruction of elastic lung tissue. It results in hyperinflation, and loss of recoil, and medical therapies are of limited benefit. Lung volume reduction surgery (LVRS) has recently emerged as an effective therapy for emphysema. LVRS involves surgical resection of diseased lung, allowing more space within the chest cavity for the remaining lung to expand and function. Unfortunately, LVRS is associated with substantial mortality (5–10%), morbidity (20–40%) and cost ($25–35,000 per operation). We have recently developed a safer, effective, and less costly approach to lung volume reduction therapy based on tissue engineering principles that can be administered through a bronchoscope. Testing of this procedure required the development of a large animal model that accurately reproduces the physiology of emphysema. This report summarizes the development and validation of such a model, and the testing of our approach, known as Bronchoscopic Lung Volume Reduction (BLVR). The model has facilitated refinement of the procedure in preparation for clinical trials.
TowardsIn-SituMonitoring of Cell Growth in Tissue Engineering Scaffolds: High Resolution Optical Techniques
Authors: Cicerone MT , Dunkers JP , Washburn NR
Published: April 2008

Inability to obtain cellular-level information about progress of cell growth in tissue-engineering (TE) scaffolds is a pervasive problem. We demonstrate that a confocal microscope with two collinear contrast mechanisms, optical coherence, and fluorescence, can be used to perform non-destructive imaging of a polymer TE scaffold containing osteoblasts. We show that the combination of the techniques shows promise for in situ measurements of cell growth in a bioreactor, even for highly opaque TE scaffolds.
Age Related Differences in Chondrocyte Viability and Biosynthetic Response to Mechanical Injury
Authors: D'Lima DD , Bergula A , Chen PC , Colwell CW , Lotz M
Published: April 2008

Mechanical trauma has been shown to cause chondrocyte death. The response of the surviving cells has not been fully characterized especially with regards to aging. This study investigates the response to injury in aging chondrocytes. Human articular chondrocytes from younger and older donor knees were cultured in agarose gel disks for three weeks. Disks were submitted to a brief 30% compressive insult (injured), or cultured in IL-lbeta (IL-1), or served as controls. Glycosaminoglycan biosynthesis was measured by radiolabeled sulfate (35SO4) uptake 48 hours after injury. Chondrocytes from the older group synthesized less glycosaminoglycan as measured by 35SO4 uptake. This ranged from a 22% to 61% reduction relative to the younger group. After injury, a further decline in glycosaminoglycan synthesis was noted in both older and younger groups. However, the decline in glycosaminoglycan synthesis was more marked in the older group. While mechanical injury results in chondrocyte death, the surviving cells exhibit the effect of injury by reduced biosynthesis and increased loss of matrix. This suggests that the impact of mechanical injury may progress beyond the traumatic event. With age, fewer cells may survive with a further decrease in biosynthetic response. This has implications in the repair response and may provide insights in the development of chondroprotective measures.
Comparative Study of Bone Cell Culture Methods for Tissue Engineering Applications
Authors: Thomas CB , Kellam JF , Burg KJL
Published: April 2008

Cells are used in bone tissue engineering applications to facilitate new bone formation in implants. Enzymatic digestion and marrow removal by either centrifugal force or syringe are three methods used to isolate the cells for culture, but each technique has benefits and drawbacks. This comparative study evaluated the effects of the three cell isolation techniques on the attachment, proliferation, and mineralization of rat bone cells. Cells were isolated, seeded, and cultured following standard protocols for each isolation method. Quantitative assays to determine metabolic activity, lactic acid production, glucose consumption, and amounts of intracellular protein, alkaline phosphatase activity, and extracellular calcium were performed. In addition, cell morphology and viability were examined qualitatively. The results indicate that the cell isolation method affects the attachment, proliferation, and type of tissue formed by cells cultured under identical conditions.
Alginate and Chitosan Standards for Tissue Engineered Medical Products
Authors: Dornish M , Dessen A
Published: April 2008

More often than not users of biopolymers obtain their starting materials from a chemical supply company. Documentation is often lacking and the user is not aware of the fact that a biopolymer's functionality in an application is inherently linked to its characteristics. As a manufacturer of ultrapure biopolymers we have often heard the comment that “your biopolymer didn't work!” More often than not, however, the functional properties of the polymer were not appropriate for the intended use. Variability in naturally occurring biopolymers can lead to failed formulations. Alginate and chitosan are biopolymers that may be used in TEMPs. Derived from natural sources, these materials are particularly complex, and thus exhibit significant variability. Consequently, in order to understand the full range of their properties there is a need for accurate characterization of these materials. The development of standards for such TEMP starting materials is necessary to ensure product uniformity, enable more complete and precise characterization and to inform both users and manufacturers of the relationships among composition, functional properties and utility. This can only lead to more successful TEMP formulations.
Standards Used in Meeting Requirements for a Model Pre-Market Approval (PMA) of a Neural Guidance Conduit
Authors: Stover L , Hubel A
Published: April 2008

A hypothetical neural guidance conduit, ‘InnervTube,’ employing autologous denatured muscle is presented in the form of a PMA as an example of how existing standards for tissue engineered medical products are used in product testing and evaluation. The performance requirements that determine the specific device characteristics are defined, along with a proposed method of manufacture, use, and control. Alternatives, contraindications, and preliminary in-situ and in-vitro results garnered from the literature are presented.
Storage and Transport Issues for Tissue Engineered Medical Products
Authors: Walsh JR , Taylor MJ , Brockbank KGM
Published: April 2008

A prominent barrier to widespread commercialization of tissue engineered medical products (TEMPs) is the development of storage and transport technologies to maintain high product viability and integrity at point of use. Advances in biostabilization and low temperature biology have produced effective preservation technologies for cells and tissues in areas of hypothermic storage, cryopreservation by freezing and vitrification, and anhydrobiotic preservation. Preservation methods are anticipated to progress in step with development of TEMPs and may ultimately influence construct designs, as the final form of these products are determined. However, development of preservation methods is complex and requires optimization of several chemical and biophysical processes to achieve maximal viability and stability. The development of standards for materials and processes used in preserving TEMPs will be integral in ensuring final product quality and integrity pertaining to pre-process treatment, materials and containment systems, preservation processes, storage, transport, restoration and post-process treatment.
A European View on Risk Management Strategies for Tissue Engineered Medical Products (TEMPs)
Authors: Geertsma RE , Kallewaard M , Wassenaar C
Published: April 2008

In order to guarantee the quality, safety and efficacy of Tissue Engineered Medical Products (TEMPs), the application of risk management strategies by all parties involved in the life cycle of TEMPs is of the utmost importance. Due to the novelty of TEMPs, their risks have not been clearly and completely identified yet. Extrapolation of experiences with related medical products indicates that the most important risks of TEMPs will relate to the transmission of disease, biocompatibility and efficacy. Many of the risk control measures included in current regulations and standards covering related product categories like medicinal products, blood (products) and medical devices are applicable in generic form to TEMPs. From a regulatory perspective control measures for TEMPs should be combined into a regulatory framework that is complementary to and connects with current European regulation on medical products. Decisions on risk acceptability should preferably be based on predefined standards. Development of internationally accepted standards is therefore essential.
Adhesive Bonding and Performance Testing of Bonded Wood Products
Authors: Frihart CR
Published: April 2008

Despite the importance of durable wood bonds, the factors that lead to durability are not well understood, and the internal forces exerted upon the bondline are often overlooked. Durability requires that the bonded assembly resist dimensional changes of wood with fluctuation of wood moisture levels. Both bonding and bond breaking steps need to be understood at cellular and nanoscale, in addition to the larger spatial scales normally examined. With both internal and external forces being significant, interphase and bulk adhesive properties need to be better understood. Systematic studies of the bonding process, the forces upon the bondline, and the locus of failure using different types of adhesives and wood species should improve our ability to design wood adhesives. Modifications of wood surfaces, along with spectroscopic and microscopic analyses, are important tools to understand bond formation and failure.
A New Low Cost Method For Measuring the Viscoelastic Behavior of Adhesives
Authors: Moonay DJ , McGregor RG , Mastria RA
Published: April 2008

A rotational benchtop Rheometer with vane spindles can be used to measure the static yield stress behavior of materials. By running at different rotational speeds, the Rheometer data can be equated with the viscoelastic information determined by an oscillating rheometer. The rotational Rheometer offers a less expensive method suitable for Quality Control needs.