Combining pot, atom and step economy (PASE) in organic synthesis. Synthesis of tetrahydropyran-4-ones

The combination of pot, atom and step economy (PASE) in the synthesis of organic molecules of medium complexity can lead to a significant 'greening' of a synthetic route. This is demonstrated by the synthesis of highly substituted tetrahydropyran-4-ones and is quantified by a series of recognised metrics, which demonstrate the efficiency of combining PASE over conventional synthetic strategies

Halogenation effects in Intramolecular Furan Diels-Alder reactions:broad scope synthetic and computational studies

For the first time a comprehensive synthetic and computational study of the effect of halogen substitution on both furan and dienophile for the intramolecular Furan Diels-Alder (IMDAF) reaction has been undertaken. Contrary to our initial expectations, halogen substitution on the dienophile was found to have a significant effect, making the reactions slower and less thermodynamically favourable. However, careful choice of the site of furan halogenation could be used to overcome dienophile halogen substitution, leading to highly functionalised cycloadducts. These reactions are thought to be controlled by the interplay of three factors: positive charge stabilisation in the transition state and product, steric effects and a dipolar interaction term identified by high level calculations. Frontier orbital effects do not appear to make a major contribution in determining the viability of these reactions, which is consistent with our analysis of calculated transition state structural data

Integrated Thermal Energy Storage for Cooling Applications

Many commercial and industrial facilities are cooled using vapor compression cycles (VCC). The performance of such systems degrades with high outdoor temperatures causing high peak electric demand increase, reduced efficiency and lower cooling capacity. An Integrated Thermal Energy Storage System (ITESS) utilizing chilled water provides additional subcooling for a VCC condenser, thereby increasing the capacity of the entire system and providing significant reductions in electric demand and consumption. The ITESS uses a dedicated chiller to cool a thermal storage tank, typically at night when electricity demand and rates may be lower. This thermal reservoir is used during the following day to sub-cool refrigerant leaving the condenser. This additional cooling increases the overall cooling capacity of the chiller without increasing the electrical demand. The following paper outlines the results of a demonstration of the ITESS at an industrial facility in Syracuse, NY. The existing 176-ton chiller, which provides cooling for air conditioning a laboratory space and chilled water for compressor testing, was retrofitted with a 33-ton supplemental chiller, 10,000-gallon water tank, four sub-coolers, and two sub-cooler pumps. The ITESS was instrumented with a number of sensors to measure critical parameters to assess its performance. The test results showed that the cooling capacity of the existing chiller increased by 2.2% - 34.2%, depending on operating conditions, with the addition of subcooling. The ITESS increased existing chiller efficiency between 0.6% - 28.5% and has the potential to reduce power demand by 0.7%-34.3%. Total energy consumption for the system was essentially unchanged, increasing on average by approximately 0.05%, well within the margin of error

Demo Abstract: R.A.V.E.N. – Remote Autonomous Vehicle Explorer Network

Unmanned aerial vehicles (UAVs) have recently become a viable platform for surveillance and exploration tasks. Several commercial quadrotor aircraft have been successfully used as surveillance equipment with groups such as United States and Canadian police forces, and additional applications for this technology could include exploration of ra-dioactive/hazmat environments, naval search and rescue, or surveying a building on fire, to name a few. Despite the agility and speed of the quadrotor platform, current systems lack the redundancy and collaboration of a multi-unit team; current implementations of quadrotor UAV flocks require expensive equipment, limiting the system to operation within range of external sensors. We propose a system for intelligently controlling multiple quadrotor UAVs using a combination of on-board vision tracking and wireless communication of attitude measurements. The proposed system uses a lead, human-controlled quadrotor and one or more quadro-tors that track and follow the lead unit autonomously. The forthcoming system aims to improve the execution time required to complete missions and increase both breadth of search and platform effectiveness

Cooperative Flight Guidance of Autonomous Unmanned Aerial Vehicles

As robotic platforms and unmanned aerial vehicles (UAVs) increase in sophistication and complexity, the ability to determine the spatial orientation and placement of the platform in real time (localization) becomes an important issue. Detecting and extracting locations of objects, barriers, and openings is required to ensure the overall effectiveness of the device. Current methods to achieve localization for UAVs require expensive external equipment and limit the overall applicable range of the platform. The system described herein incorporates leader-follower unmanned aerial vehicles using vision processing, radio-frequency data transmission, and additional sensors to achieve flocking behavior. This system targets search and rescue environments, employing controls, vision processing, and embedded systems to allow for easy deployment of multiple quadrotor UAVs while requiring the control of only one. The system demonstrates a relative localization scheme for UAVs in a leader-follower configuration, allowing for predictive maneuvers including path following and estimation of the lead UAV in situations of limited or no line-of-sight

Distributed opportunistic argumentation guided by autonomous agent interaction

Within a distributed system, autonomous agents may find it necessary to cooperate in order to achieve their objectives. Interaction protocols provide standard frameworks within which to conduct common classes of interaction, but they are only useful when the agents using them have a common interpretation of the constraints imposed by those protocols. In open systems, where there are no system-wide objectives and components are contributed from a variety of sources, this is difficult to ensure. An agent within a sufficiently complex environment will find it necessary to draw inferences from information sources of varying integrity and completeness. Given flawed or incomplete information, it may be necessary for an agent to resort to nonmonotonic reasoning in order to be able to make concrete decisions within limited windows of opportunity. This can be expected to create inconsistencies in the joint beliefs of agents which can only be repaired by dialogue between peers. To verify and repair all possible sources of inconsistency is impractical for any sizable body of inference however—any belief revision must therefore be subject to prioritisation. In this thesis, we introduce a mechanism by which agents can perform opportunistic argumentation during dialogue in order to perform distributed belief revision. An interaction portrayal uses the protocol for a given interaction to identify the logical constraints which must be resolved during the interaction as it unfolds. It then compares and reconciles the expectations of agents prior to the resolution of those constraints by generating and maintaining a system of arguments. The composition and scope of arguments is restricted in order to minimise the information exchange whilst still trying to ensure that all available admissible viewpoints are adequately represented immediately prior to any decision. This serves both to make interaction more robust (by allowing agents to make decisions based on the distributed wisdom of its peer group without being explicitly directed by a protocol) and to reconcile beliefs in a prioritised fashion (by focusing only on those beliefs which directly influence the outcome of an interaction as determined by its protocol)

Validation of a finite element model of the cold roll forming process on the basis of 3D geometric accuracy

Cold roll forming is an incremental sheet metal forming process used to supply products to numerous industries such as automotive, architecture and construction, etc. In recent years there has been an increase in the demand by customers for high value products, through the forming of high strength materials, or complex profiles. Such demands increase the challenges faced by the tooling designer to bring a successful product through from design to manufacture, on time and within specification. Finite element (FE) simulations are increasingly applied in industry due to the desired advantage of reducing design iterations by allowing the designer to investigate the effects of parameter changes, without the risk of expensive tooling costs. Some successful validation of the numerical modelling of the cold roll forming process can be found in literature, in particular when analysing the strain distribution across the material or comparing the final rolled profile geometry. However, cold roll forming is a continuous process and no one has published work on the measurement of the profile on a pass to pass basis, in particular, the three dimensional geometry of the profile. Experimental trials were carried out to obtain a 3D point cloud model of the top surface of a roll formed section. This investigation aimed to quantify how accurate FE simulation may be in relation to physical data

One-dimensional reflection by a semi-infinite periodic row of scatterers

AbstractThree methods are described in order to solve the canonical problem of the one-dimensional reflection by a semi-infinite periodic row of identical scatterers. The exact reflection coefficient R is determined. The first method is associated with shifting the domain by a single period and subsequently considering two scatterers, one being a single scatterer and the second being the entire semi-infinite array. The second method determines the reflection coefficient RN associated with a finite array of N scatterers. The limit as N→∞ is then taken. In general RN does not converge to R in this limit, although we summarize various arguments that can be made to ensure the correct limit is achieved. The third method considers direct approaches. In particular, for point masses, the governing inhomogeneous ordinary differential equation is solved using the discrete Wiener–Hopf technique

Socioeconomic disparities in orthodontic treatment outcomes and expenditure on orthodontics in England's state-funded National Health Service:A retrospective observational study

Percentage distribution/means of variables used in the adjusted treatment outcomes analyses, by socioeconomic status (SES). Additional file 1 contains information on the distribution of variables used to adjust for potential confounding: IOTN AC scores, gender, and age. This information is provided by IMD quintile. (DOCX 16 kb