Alternative Project Delivery Systems: Applications and Legal Limits in Transportation Projects

This paper presents the results of a comprehensive survey of the legal codes of all the 50 states in the United States regarding alternative project delivery systems in transportation projects. In the past decade there has been a surge of legislation allowing state transportation officials much more flexibility regarding the choice of project delivery systems. These delivery systems are usually selected based on a combination of price and quality. Specific delivery systems studied in this paper are Design-Build, Construction Management at Risk, and Public-Private-Partnership. The background and history of the emergence of these new delivery systems are studied in this paper. The research showed that in many states, alternative delivery systems may be allowed but with specific restrictions. For each state, all of these delivery systems have been researched and placed into one of the following distinguishable categories: (1) fully authorized; (2) authorized but needs extra approvals; (3) authorized for a pilot program and/or with some limitations; (4) not authorized. The output of the survey gives valuable snapshots over the status of each delivery system in regards to its legality in different parts of the country as of December 2006. Comparing the results of this survey with the surveys done previously shows that the trend is to allow states more flexibility in the choice of project delivery systems.     

Dynamic Data Driven Application System for Plume Estimation Using UAVs

In this article, a full dynamic data-driven application system (DDDAS) is proposed for dynamically estimating a concentration plume and planning optimal paths for unmanned aerial vehicles (UAVs) equipped with environmental sensors. The proposed DDDAS dynamically incorporates measured data from UAVs into an environmental simulation while simultaneously steering measurement processes. In order to assimilate incomplete and noisy state observations into this system in real-time, the proper orthogonal decomposition (POD) is used to estimate the plume concentration by matching partial observations with pre-computed dominant modes in a least-square sense. In order to maximize the information gain, UAVs are dynamically driven to hot spots chosen based on the POD modes. Smoothed particle hydrodynamics (SPH) techniques are used for UAV guidance with collision and obstacle avoidance. We demonstrate the efficacy of the data assimilation and control strategies in numerical simulations. Especially, a single UAV outperforms the ten static sensors in this scenario in terms of the mean square error over the full time interval. Additionally, the multi-vehicle data collection scenarios outperform the single vehicle scenarios for both static sensors at optimal positions and UAVs controlled by SPH.     

Electrohydrodynamic drying: Can we scale-up the technology to make dried fruits and vegetables more nutritious and appealing?

Electrohydrodynamic (EHD) drying is a promising technology to better preserve the nutritional content and sensory appeal of dried fruits and vegetables. To successfully scale up this technology, we need to rethink the current EHD dryer designs. There is also a significant potential to further enhance the nutritional content and sensory quality of the dried products by optimizing EHD process parameters. This study particularly highlights the current bottlenecks in scaling up the technology and improving nutrient retention and sensory appeal of the dried products. We discuss plausible future pathways to further develop the technology to produce highly nutritious dried products. Particular emphasis has been given to quantifying the residual nutritional and sensory properties of EHD dried products, and possible EHD dryer configurations for farmers and the industry. Concerning the nutritional content, EHD drying preserves vitamins, carotenes, and antioxidants significantly better than convective air drying. From the sensory perspective, EHD drying enhances the color of dried products, as well as their general appearance. With respect to scalability, placing the fruit on a grounded mesh electrode dries the fruit much faster and more uniformly than the grounded plate electrode. Future research should be directed toward simultaneous measurements of multiple food nutrients and sensory properties during EHD drying with a grounded mesh collector. Quantifying the impact of the food loading density on drying kinetics and energy consumption of the EHD drying process should also be a future research goal. Research comparing EHD drying with commercially available drying methods such as freeze-drying, microwave-drying, and infrared drying should also be carried out. This study gives promising insight toward developing a scalable novel thermal drying technology tailored to the requirements of the current and future society.     

Effect of reformed biogas as a low reactivity fuel on performance and emissions of a RCCI engine with reformed biogas/diesel dual-fuel combustion

Biogas can be used as a less expensive continuance renewable fuel in internal combustion engines. However, variety in raw materials and process of biogas production results in different components and percentages of various elements, including methane. These differences make it difficult to control the combustion, effectively, in internal combustion engines. In this research, under cleaning and reforming process, biogas components were fixed. Then the effect of reformed biogas (R.BG) was investigated, numerically, on the combustion behavior, performance and emissions characteristics of a RCCI engine. A 3D-computational modeling has been performed to validate a single-cylinder compression ignition engine in conventional diesel and dual-fuel operations at 9 bar IMEP, 1300 rpm. Then, the combustion model of the RCCI engine was simulated by replacing diesel fuel with 20%, 40% and 60% of R.BG as a low reactivity fuel while remaining constant input total fuel energy per cycle. The results demonstrated that when the R.BG substitution ratio increases with a constant equivalence ratio of 0.43, the mean combustion temperature decreases to 1354 K, 1312 K, 1292 K which are about 3.5%, 6.6%, 7.9% lower than the conventional diesel combustion, respectively. The maximum in-cylinder pressure increases up to 22.63%. Instead, it results in 2.3%, 7.9%, and 14.5% engine power output losses, respectively. Also, the NOx emission, against CO, is decreased by 50%. Soot and UHC emissions were found to be slightly decreased while was used R.BG more than 40%.     

Characterisation of natural honey proteins: implications for the floral and geographical origin of honey

Characterisation of honey proteins has been considered advantageous for differentiating floral and geographical origin of honey. We analysed protein profiles of multi‐ and mono‐floral honey samples from different regions and harvest dates. The molecular masses of chromatographic peaks were in the range of 10–>200 kDa. Owing to comparable molecular masses, interesting correlation between profiles of honey proteins reported earlier and observed in this study could be established. Chromatograms of honey proteins revealed three novel peaks of molecular masses ～220, 129 and 26 kDa. Statistical analysis of peak areas showed that the 84‐kDa peak was different among all honey samples and the 220‐kDa peak was important for differentiation between multi‐ and mono‐floral honey samples. Chromatograms of several‐year‐old honey samples were different from fresh samples because of depletion of high molecular mass peaks that indicated in situ proteolysis. The results supported the notion of applying gel filtration as cost‐effective and robust technique for honey protein characterisation.