This thesis considers the impact of differential skid resistance between wheel paths on the speed at which a vehicle can safely negotiate a curve. Currently the New Zealand Transport Agency undertakes measurement of the co-efficient of friction on the state highway network by measuring both wheel paths, but taking the average value to represent the level of skid resistance available. Part of the basis for this approach is that modern cars have Electronic Stability Control that has historically been considered to negate the effects of any differential friction. Aside from straight line braking testing, little research has been done on the impacts of differential friction on curves. There are however a number of areas of research that can be related to this topic.By PC Crash simulation modeling, this research identifies that there are a number of gaps in our understanding of the relationship between vehicles maneuvering on a curve and the effect of varying skid resistance. It concludes that taking the average of the two values is not the same as considering them separately and, that as the difference in the co-efficient of friction between the wheel paths increases, the speed at which a vehicle can safely maneuver around a curve decreases. It has also been found that when Electronic Stability Control is used the speed at which the vehicle can safely maneuver around a curve decreases further.

One of the factors contributing to motor vehicle crashes is lack of sufficient friction at the tire-pavement interface. Although the relationship between surface friction and roadway safety has long been recognized, attempts to quantify the effect of pavement skid resistance on wet accident rates have produced inconsistent results. This thesis analyzes the relationships between skid resistance, accident, and traffic data for the state of Virginia. The correlation between wet skid resistance measured with a locked-wheel trailer using a smooth tire and wet accident rates is examined. Additionally, the influence of traffic volumes on accident rates is considered. The research used accident and skid data from the Virginia wet accident reduction program as well as from sections without pre-identified accident or skid problems. The wet accident data was aggregated in 1.6 km (1 mi) sections and divided by the annual traffic to obtain wet accident rates. The minimum skid number measured on each of these sections was then obtained and added to the database. Regression analyses indicated that there is statistically significant effect of skid resistance on wet accident rate; the wet accident rate increases with decreasing skid numbers. However, as expected, skid resistance alone does a poor job of modeling the variability in the wet accident rates. In addition, the wet accident rate also decreases with increasing traffic volume. Based on the data studied, a target skid number (SN(64)S) of 25 to 30 appears to be justified. / Master of Science

No description available.

Syfte: Att mäta turisternas konsumtion i samband med ett större idrottsevenemang samt att beräkna skatte- och sysselsättningseffekter till följd av denna under Skid-VM i Falun år 2015. Metod: Turisternas konsumtion har i denna studie mätts genom att ett urval av besökarna på Skidspelen 2013 fört dagbok över sin konsumtion. Vi har även använt sekundärdata i form av en konsumtionsundersökning som är genomförd under Svenska Skidspelen 2012 samt uppgifter från en rapport författad av HUI Research AB. Slutsats: Tre olika scenarion har använts för att beräkna skatte och sysselsättningseffekter. Ett lågt scenario där vi räknar med 140 000 sålda endagsbiljetter vilket är samma antal som Skid- VM i Falun 1993. Ett medelhögt där vi räknar med 200 000 sålda endagsbiljetter vilket är vad arrangören förväntar sig samt slutligen ett högt scenario med 270 000 sålda endagsbiljetter vilket är vad som såldes under Skid-VM i Oslo 2011. Beroende på valt scenario kommer turisternas totala konsumtion i regionen att uppgå till mellan 147 och 197 miljoner kronor. Denna omsättningsökning uppskattas leda till att mellan 85 och 111 arbetstillfällen skapas i regionen på kort sikt. Summan av samtliga skatter och avgifter uppgår till mellan 27 och 36 miljoner kronor. / Purpose: To measure the tourist expenditure due to a major sporting event and to calculate the resulting tax and employment effects due to the FIS Nordic World Ski Championships in Falun 2015. Methodology: We have recruited a number of people who visited Svenska Skidspelen 2013 to keep a diary of their expenditures. We have used secondary data as well from a survey from Svenska Skidspelen 2012 and a report by HUI Research AB. Conclusion: We have used three different scenarios in our calculations. A low scenario where we anticipate 140 000 sold one day tickets which is the same amount that was sold during the FIS Nordic World Ski Championships in Falun 1993. A medium scenario where we anticipate 200 000 sold one day tickets which is the same number as the organizer anticipates. And finally a high scenario where we anticipate 270 000 sold tickets which is the same number of tickets as sold during the FIS Nordic World Ski Championships in Oslo 2011. Depending on the scenario the total tourist expenditure will be between 147 and 197 million SEK. This increase in turnover will result in the possible creation of 85 and 111 job opportunities in the short run. The aggregated taxes and fees will be between 27 and 36 million SEK.

The annual cost of corrosion in the United States Navy and Coast Guard is in excess of $2.7 billion dollars. The salt water environment provides a ripe surrounding for rapid corrosion and deterioration of ship decking, which requires frequent and expensive maintenance. Decks of ships are susceptible to corrosion and wear, but must also maintain a non-slip surface in a constantly wet environment. Few options for non-skid deck materials are currently approved for use by the Navy and require frequent and expensive maintenance or replacement. A new material known as Laser Deposited Non-Skid, currently used in industrial flooring applications, shows potential for serving as a more durable non-skid material with extended service life and greater resistance to corrosion. The purpose of this research is to investigate the feasibility of Laser Deposited Non-Skid in decks of ships and to compare the corrosion, wear and cost data with existing deck materials. Sample plates of A36 and A572 steel and 5086 and 5456 marine grade aluminum alloy were coated with selected non-skid materials and subjected to laboratory salt fog testing and corrosion in environmental conditions in the Caribbean Sea. Wear behavior among non-skid materials was evaluated through wear cycles, measurement of coefficient of friction, and surface characterization. Salt fog testing was more corrosive than the actual operational environment in all cases and the Laser Deposited Non-Skid samples had the best resistance to wear and corrosion. The Peel and Stick Non-Skid demonstrated corrosion by undercutting while the Traditional Non-Skid corroded through the material. The relative area did not correlate well with friction or wear mass loss. Aluminum Laser Deposited Non-Skid appears suitable for use as a deck material on small boats. More research is needed to evaluate maintenance issues and possible stress cracking associated with the Laser Deposited Non-Skid on steel decks.

This thesis consists of two parts. The first part includes analyses of the correlation between the results of two Aggregate Imaging System (AIMS) units. These analyses have led to refinements of the AIMS analysis methods of angularity and texture, which resulted in reduced variability in the results and better correlation between the two AIMS units. The refined analysis methods were used to establish a database of the shape characteristics of about 100 aggregate samples from the state of Texas and to propose a new method for the classification of aggregates based on their shape characteristics. This new method of classification is for use in the Texas Department of Transportation (TxDOT) wet weather accident reduction program (WWARP). The use of AIMS texture index and variability in texture within an aggregate source is proposed instead of the British Polish Value (BPV) for classifying aggregates used in pavement surfaces. The second part of the thesis investigates the relationship between shape characteristics and asphalt pavement skid resistance. Many states have implemented wet weather accident reduction programs aimed at maintaining acceptable levels of pavement skid resistance. Proper aggregate selection before construction aids in maintaining acceptable levels of skid resistance throughout the life of the pavement. Several predictive models of pavement skid resistance have been developed over the years. Some of these models account for the influence of aggregate characteristics on pavement skid resistance, primarily through incorporating the results of the BPV test in the model. However, the BPV test is known to have high variability and dependence on experimental factors that are not related to the actual aggregate resistance to polishing. AIMS offers a method to measure aggregate shape characteristics directly in a relatively short period of time. The new method for relating aggregate shape characteristics to pavement skid resistance was verified by relating skid resistance measurements from field test sections to measured aggregate properties from the laboratory. This methodology is expected to be the basis for further study to form a more comprehensive and verified model for the prediction of pavement skid resistance that incorporates measured aggregate properties from the AIMS system.

The skid resistance of asphalt pavement is a major characteristic that determines the driving safety on a road, especially under wet surface conditions. Skid resistance is primarily a function of the microtexture and macrotexture of a pavement surface. Microtexture is influenced by aggregate surface characteristics and is required to disrupt the continuity of surface water film and attain frictional resistance between the tire and the pavement surface. Macrotexture is affected mostly by mixture design or aggregate gradation and contributes to skid resistance by providing drainage paths of water that can be otherwise trapped between a tire and a pavement surface. The increase in macrotexture contributes to preventing hydroplaning and improving wet frictional resistance, particularly at high speeds. While much research has been conducted in the past to identify material factors that affect skid resistance, there is still a need to develop a model for predicting asphalt pavement skid resistance as a function of mixture characteristics and traffic level. The purpose of this study was to develop such a model based on extensive laboratory experiments and field measurements involving different mixture types and aggregate sources. The model incorporates functions that describe the resistance of aggregates to polishing and aggregate size distribution. The aggregate resistance to polishing was quantified by measuring aggregate texture using the Aggregate Imaging System (AIMS) before and after polishing in the Micro-Deval device. The analysis in this dissertation demonstrates how this model can be used to design mixtures and classify aggregates that provide desirable skid resistance levels.

Faced with continuously increasing maintenance due to aging infrastructure, the Texas Department of Transportation (TxDOT) is evaluating the potential impact of reduced funding on highway safety. The main objective of this thesis is to develop a methodological procedure to identify threshold levels of pavement skid resistance for highways in the context of traffic crashes, assisting TxDOT Administration and engineers in making proper maintenance decisions. As a result, the efficiency and safety of the highway system could be preserved. The scope of this study covers all types of state-maintained highways in Texas. The primary objectives of this thesis include: 1) synthesis of literature; 2) quantification of the relationship between crash risk and pavement skid resistant; 3) determination of critical skid resistant threshold levels; and, 4) benefit cost analysis. A detailed methodology framework was developed and a comprehensive database was generated from four data files containing pavement, geometry, traffic, and crash information to support this research. The impact of skid resistance level on crash risks was proven to be significant based on the results of regression analysis and insights provided by TxDOT experts. The quantitative relationships between crash risk and skid resistance were quantified using the Crash Rate Ratio method. Hierarchical structure grouping was used to categorize the entire network into homogeneous groups based on traffic level, roadway alignment and other factors. Critical skid resistance threshold levels were determined for the whole state as well as for stratified highway groups. Finally, benefit/cost ratio analyses were conducted to evaluate the effectiveness of pavement maintenance treatments to restore or increase skid resistance. / text

Det övergripande syftet med denna litteraturgranskning är att ta reda på hur idrotten har förändrats i läroplanen från 1962 till 2011 och studien tar även upp hur läroplanerna har utvecklats ur ett samhällsperspektiv. Studien visar att ämnet idrott har genomgått en tydlig förändring och att skid- och skridkoåkningen har försvunnit ur läroplanen sakta men säkert. I resultatdelen tas det även upp hur samhället har haft en bidragande faktor till läroplanens utformning. Metoden till arbetet är en litteraturgranskning där läroplanerna sätter grunden för studien. För att stärka resultatdelen så har även en innehållsanalys använts för att förtydliga skid- och skridskoåkningens förändring.

A skid steer loader is a machine used in construction for multiple tasks. Its small size and versatility makesit a use-full addition to any work site. The machine is driven by a combustion engine that in turn powers ahydraulic pump. This hydraulic fluid from the pump is then directed to either motor to propel the vehicle. Twospeed motors are used to allow high-speed operation. A problem present in the current design of the hydraulicsystem for a skid steer loader is its tendency to jerk when shifting speed at low temperatures. In an effort toidentify potential problems and rectify those, two models will be constructed in Simulink. One is a model ofthe whole system, where the pump and both motors are included as well as the machine itself. The other modelis designed to predict the system behaviour of one motor and a pump in a flywheel test rig. Also auxiliarycomponents are included in the models, including the two-speed shifting valve and pressure release valves. Bothmodels will predict the system behaviour from a set of input variables, including temperature, oil viscosity andgeometrical parameters. Improvements to the design where identified by analysing the simulation data. It wasfound that system performance could be enhanced by switching to an alternative notch shape of the two-speedshifting valve.