7,887 research outputs found

    Cost implications of various Euro 4 and 5 after treatment solutions for heavy duty diesel vehicles

    Get PDF
    This study is firstly a short review of the types of exhaust systems predicted for Euro 4 (2005) and Euro 5 (2008), particularly focussed on the effects of combined NOx (nitrogen oxides) and PM (particulate matter) aftertreatment systems. Secondly, it explores in detail the implications of using a liquid secondary water-based fuel of urea on board heavy duty diesel vehicles in Europe as a basis for NOx reduction via selective catalytic reduction (SCR). Some of the main points that become apparent when using integrated SCR systems are: the potential costs of increased urea production in Europe (including possible fuel taxation), refuelling issues, secondary fuel cost, logistics of urea supply, and cost of implementation of the urea fuel delivery method. From the original equipment manufacturers view, the hardware cost will be increased substantially when compared to current silencer systems. From the vehicle owner’s point of view, the possibility of large running cost increases is not desired, and the system solution cost and its benefits must ultimately be acceptable. This paper will attempt to put the life-time costs of various systems within perspective in order to assess the feasibility of implementing selective catalytic reduction systems (SCR) Europe wide for the near future

    U.S. Patent Literature Survey of Agrobacterium-Mediated Transformation of Sweet Potato (Ipomoea Batatas)

    Get PDF
    A team of researchers and patent information scientists at Franklin Pierce Law Center were asked to evaluate the patent and literature landscape related to the Agrobacterium-mediated transformation in sweet potato with respect to the U.S. patents and patent applications. This report provides a patent landscape of the Agrobacterium-mediated transformation of sweet potato. The report includes the applicable methods of transformation and has also included certain patents and patent applications which claim a transformed plant by virtue of these methods. In certain cases, the claim structure covers Agrobacterium-mediated transformation technology via system and composition of matter claims and not the more prevalent method claims. Sweet potato plant (Ipomoea batatas) is adaptable to a broad range of agroecological conditions and fits in low input agriculture. It is highly productive even under adverse farming conditions. Sweet potato is grown in more than 100 countries as a valuable source of food, animal feed and industrial raw material. It is a staple crop in many South East Asian and African countries. Traditional plant breeding has contributed to the improvement of sweet potato, especially in developed countries such as the U.S.A. and Japan. Because of the biological complexities of sweet potato, sexual hybridization strategies have not been very effective in developing improved cultivars. Confidential Therefore, biotechnological tools, such as gene transfer, are very attractive in sweet potato improvement, as they enable direct introduction of desirable genes from other sources into preadapted cultivars

    Indexing with coded deltas—a data compaction technique

    Get PDF
    The paper describes the coded delta scheme, which is one of the methods used by the Census Research Unit, University of Durham, for compacting the 1971 U.K. census data. It evaluates the merits and limitations of the technique in relation to the characteristics of the data set and other techniques available for compact encoding of numeric and string data

    Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

    Full text link
    This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201

    Estimations of topographically correct regeneration to nerve branches and skin after peripheral nerve injury and repair.

    Get PDF
    Peripheral nerve injury is typically associated with long-term disturbances in sensory localization, despite nerve repair and regeneration. Here, we investigate the extent of correct reinnervation by back-labeling neuronal soma with fluorescent tracers applied in the target area before and after sciatic nerve injury and repair in the rat. The subpopulations of sensory or motor neurons that had regenerated their axons to either the tibial branch or the skin of the third hindlimb digit were calculated from the number of cell bodies labeled by the first and/or second tracer. Compared to the normal control side, 81% of the sensory and 66% of the motor tibial nerve cells regenerated their axons back to this nerve, while 22% of the afferent cells from the third digit reinnervated this digit. Corresponding percentages based on quantification of the surviving population on the experimental side showed 91%, 87%, and 56%, respectively. The results show that nerve injury followed by nerve repair by epineurial suture results in a high but variable amount of topographically correct regeneration, and that proportionally more neurons regenerate into the correct proximal nerve branch than into the correct innervation territory in the ski

    Systemically Administered, Target-Specific, Multi-Functional Therapeutic Recombinant Proteins in Regenerative Medicine

    Get PDF
    Growth factors, chemokines and cytokines guide tissue regeneration after injuries. However, their applications as recombinant proteins are almost non-existent due to the difficulty of maintaining their bioactivity in the protease-rich milieu of injured tissues in humans. Safety concerns have ruled out their systemic administration. The vascular system provides a natural platform for circumvent the limitations of the local delivery of protein-based therapeutics. Tissue selectivity in drug accumulation can be obtained as organ-specific molecular signatures exist in the blood vessels in each tissue, essentially forming a postal code system (“vascular zip codes”) within the vasculature. These target-specific “vascular zip codes” can be exploited in regenerative medicine as the angiogenic blood vessels in the regenerating tissues have a unique molecular signature. The identification of vascular homing peptides capable of finding these unique “vascular zip codes” after their systemic administration provides an appealing opportunity for the target-specific delivery of therapeutics to tissue injuries. Therapeutic proteins can be “packaged” together with homing peptides by expressing them as multi-functional recombinant proteins. These multi-functional recombinant proteins provide an example how molecular engineering gives to a compound an ability to home to regenerating tissue and enhance its therapeutic potential. Regenerative medicine has been dominated by the locally applied therapeutic approaches despite these therapies are not moving to clinical medicine with success. There might be a time to change the paradigm towards systemically administered, target organ-specific therapeutic molecules in future drug discovery and development for regenerative medicine
    • …
    corecore