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Harris J.M.,Duke University | Reyes C.,Triangle Engineering | Lopez G.P.,Duke University
Journal of Diabetes Science and Technology

Clinical management of diabetes must overcome the challenge of in vivo glucose sensors exhibiting lifetimes of only a few days. Limited sensor life originates from compromised enzyme stability of the sensing enzyme. Sensing enzymes degrade in the presence of low molecular weight materials (LMWM) and hydrogen peroxide in vivo. Sensing enzymes could be made to withstand these degradative effects by (1) stabilizing the microenvironment surrounding the sensing enzyme or (2) improving the structural stability of the sensing enzyme genetically. We review the degradative efect of LMWM and hydrogen peroxide on the sensing enzyme glucose oxidase (GOx). In addition, we examine advances in stabilizing GOx against degradation using hybrid silica gels and genetic engineering of GOx. We conclude molecularly engineered GOx combined with silica-based encapsulation provides an avenue for designing long-term in vivo sensor systems. © Diabetes Technology Society. Source

Mirzadeh I.,Swedish Road and Transport Research Institute | Birgisson B.,Triangle Engineering
Journal of Civil Engineering and Management

Energy price is related to more than half of the total life cycle cost of asphalt pavements. Furthermore, the fluctuation related to price of energy has been much higher than the general inflation and interest rate. This makes the energy price inflation an important variable that should be addressed when performing life cycle cost (LCC) studies re- garding asphalt pavements. The present value of future costs is highly sensitive to the selected discount rate. Therefore, the choice of the discount rate is the most critical element in LCC analysis during the life time of a project. The objective of the paper is to present a discount rate for asphalt pavement projects as a function of interest rate, general inflation and energy price inflation. The discount rate is defined based on the portion of the energy related costs during the life time of the pavement. Consequently, it can reflect the financial risks related to the energy price in asphalt pavement projects. It is suggested that a discount rate sensitivity analysis for asphalt pavements in Sweden should range between –20 and 30%. © 2015 Vilnius Gediminas Technical University (VGTU) Press Source

Wedawatta G.,Triangle Engineering | Ingirige B.,University of Salford | Proverbs D.,University of the West of England
Journal of Flood Risk Management

Flooding can have a devastating impact on businesses, especially on small- and medium-sized enterprises (SMEs) who may be unprepared and vulnerable to the range of both direct and indirect impacts. SMEs may tend to focus on the direct tangible impacts of flooding, limiting their ability to realise the true costs of flooding. Greater understanding of the impacts of flooding is likely to contribute towards increased uptake of flood protection measures by SMEs, particularly during post-flood property reinstatement. This study sought to investigate the full range of impacts experienced by SMEs located in Cockermouth following the floods of 2009. The findings of a questionnaire survey of SMEs revealed that businesses not directly affected by the flooding experienced a range of impacts and that short-term impacts were given a higher significance. A strong correlation was observed between direct, physical flood impacts and post-flood costs of insurance. Significant increases in the costs of property insurance and excesses were noted, meaning that SMEs will be exposed to increased losses in the event of a future flood event. The findings from the research will enable policy makers and professional bodies to make informed decisions to improve the status of advice given to SMEs. The study also adds weight to the case for SMEs to consider investing in property-level flood risk adaptation measures, especially during the post flood reinstatement process. © 2012 Blackwell Publishing Ltd and The Chartered Institution of Water and Environmental Management (CIWEM). Source

Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.93K | Year: 2011

This Small Business Innovation Research (SBIR) Phase I project will investigate the feasibility of developing a laser-based rapid monitoring gauge for accurate non-contact downhole stress measurement in drilling operations of the geosciences and oil and gas industries. Conventional downhole stress measurement, which commonly uses hydrofracturing, is complex, slow, inaccurate and detrimental to the environment. The proposed innovation features fast non-contact laser interrogation, rugged portable configuration, and on-line data processing and presentation, which offers great convenience for field applications. The proposed stress gauge is environment-friendly in operation as well. This Phase I effort will fabricate a laboratory assembly and demonstrate the research concept. A feasibility demonstration will be conducted on the geologic materials. Successful research and development will result in a non-contact, rapid measurement device for stress evaluation in downhole applications. The broader/commercial impacts of this research are in two aspects. First, the innovation will impact the 300 million dollar domestic annual market (0.5 ? 1% of the total operating cost) for down-hole stress measurement. The second aspect concerns social impact: conventional down-hole stress measurement is based on the hydrofracturing process, which has been challenged by environmental groups for its potential to contaminate underground water resources. Forthcoming legislation will provide stricter EPA regulation of the use of hydrofracturing. The proposed innovation, if successful, will provide an alternative method of downhole in-situ stress measurement that is not only simple, fast, and accurate, but also environment-friendly in order to ensure our environmental sustainability for generations to come.

Salicru M.,University of Barcelona | Fleurent C.,GIRO Inc. | Armengol J.M.,Triangle Engineering
Transportation Research Part A: Policy and Practice

Urban public transit provides an efficient means of mobility and helps support social development and environmental preservation. To avoid loss of ridership, transit authorities have focussed on improving the punctuality of routes that operate using timetables. This paper presents a new approach to generating run-time values that is based on analytical development and micro simulations. The work utilizes previous research (described herein) and the experience acquired by Transports Metropolitans de Barcelona (TMB) in operating bus routes based on timetables. Using a sample of historical data, the method used for generating run-time values consists of the following steps: purging and screening atypical trips, based on the consideration of confidence intervals for median trips; segmenting the day into time bands based on the introduction of a new hierarchical classification algorithm; creating initial run-time values based on criteria derived from statistical analysis; adjusting and validating initial run-time values using micro simulations; and evaluating incident-recovery times at the end of trips in order to guarantee the punctual departure of the next trip in the vehicle schedule. To favour service improvement, we also introduced certain indicators that can identify the root causes of non-compliance. As a final step, in order to ensure the applicability and use of the model, we promoted the development of our model within the framework of the HASTUS™ software solution. © 2011 Elsevier Ltd. Source

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