Anburaj Muthumani

Parkinson’s Disease Is Associated with Greater Regularity of Repetitive Voluntary Movements

Bradykinesia is a cardinal symptom of Parkinsons disease (PD). Both aging and disease are shown to be associated with decreased adaptability to environmental stresses characterized by reduced complexity (or increased regularity) of biorhythms. The purpose of this study was to investigate the regularity of movement in individuals with PD, and the effect of dopaminergic medication. Nine subjects with PD and eight controls performed wrist flexion/extension movements at maximal velocity and range of motion. Subjects with PD were tested under two medication conditions. Approximate entropy (ApEn) was calculated to assess the regularity of the movement, with the smaller value associated with the greater regularity. Data revealed that subjects with PD had lower ApEn values than controls. Medication did not alter the ApEn values. These findings demonstrate that impaired voluntary movement in individuals with PD is associated with increased regularity of movement and this exaggerated regularity appears less sensitive to anti-PD medication.

Safety Effects of Fixed Automated Spray Technology Systems

Fixed automated spray technology (FAST) has emerged as a solution to provide quick, effective service delivery to high-risk locations prone to icy conditions or with high traffic volumes. The Colorado Department of Transportation has installed and used FAST on bridges since 1998, with 32 units currently installed on bridges around the state. There is some concern regarding the effectiveness of FAST in reducing accidents during winter weather. Previous studies of FAST have considered the changes to crash occurrence following deployment, but these studies were basic and compared seasonal figures or rates without accounting for site conditions. To address this shortcoming, an observational before–after study with the empirical Bayes technique was used to determine the effect of FAST systems on crash frequencies. The results revealed that at sites where crashes were reduced, FAST systems contributed to an annual reduction of 2% on multilane rural highways, 16% to 70% on urban Interstates, 31% to 57% on rural Interstates, and 19% to 40% on interchange ramps between Interstates. However, at some sites, safety deteriorated with an increase in crashes. Although the precise causes of such increases are not completely clear, they may have been the result of increased traffic, systems not being maintained properly, or systems applying fluids in improper amounts or at the wrong time. On the basis of the collective results, high-traffic, high-crash severity locations are most suitable for FAST deployment.

Snow and Ice Control Environmental Best Management Practices

There is a need for the identification of environmental best management practices (BMPs) to aid in responsible and cost-effective operation of winter maintenance programs. State Departments of Transportation (DOTs) are continually challenged to provide a high level of service on winter roadways and improve safety and mobility in a cost-effective manner, while at the same time minimizing adverse effects to the environment, vehicles, and transportation infrastructure. Understanding and minimizing the negative impacts of deicers is critical to effective and responsible winter maintenance operations. Increasing contamination from the continued use of snow and ice control products has become a significant environmental concern that has detrimental effects on air, water, soil, vegetation, humans, and wildlife. Snow and ice control BMPs have been developed in all aspects of winter maintenance operations. This paper will focus on snow and ice control BMPs with the greatest potential to decrease the environmental impacts of winter maintenance operations including proper material storage and handling, applying the right amount of material in the right place at the right time, and facility management and post storm clean-up. By utilizing the identified best practices, an organization can realize cost and material saving, reduced person and vehicle hours and emissions, and realize a reduction in the impacts of snow and ice control operations on the environment.

Deicer Impacts on Concrete Bridge Decks: A Comparative Study of Field Cores from Potassium Acetate and Sodium Chloride Environments

The use of chemical deicers in cold regions has raised concerns over their potential negative effects on the performance and durability of concrete infrastructure. Extensive studies have been conducted in the laboratory setting, often in an accelerated manner, which reported the chemical and physical deterioration of concrete as a function of deicer type. Yet, little research has been published on how the deterioration of concrete bridge decks in the field environment is affected by their exposure to deicers, where the durability of concrete is also affected by temperature cycles and mechanical loadings. This work reports a comparative study of field cores taken from two select Nebraska concrete decks and from two select Utah concrete decks. The Nebraska decks had been exposed to mainly potassium acetate (KAc) deicers, whereas the Utah decks had been exposed to mainly sodium chloride (NaCl) deicers. The field cores were tested for their mechanical properties and transport properties. They were also subjected to staining tests to detect possible chloride penetration, carbonation, and aggregate silica reaction (ASR), and subjected to petrographic analysis to characterize their paste and air contents. The concrete cores from Nebraska exhibited more significant degradation, relative to those from Utah. Specifically, the exposure to KAc deicer led to significant reduction in mechanical properties (compressive strength, splitting tensile strength, and microhardness) and more signs of ASR. This case study sheds some light on this complex issue of concrete durability and raises the awareness over the risk of using KAc deicers on concrete structures and components.