Initial operation of a solar heating and cooling system in a full-scale solar building test facility

The Solar Building Test Facility (SBTF) was constructed to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test the performance of a complete solar heating and cooling system, (3) investigate component interactions, and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is printed along with the objectives, test approach, expected system performance, and some preliminary results

Coherent X-ray Diffractive Imaging; applications and limitations

The inversion of a diffraction pattern offers aberration-free diffraction-limited 3D images without the resolution and depth-of-field limitations of lens-based tomographic systems, the only limitation being radiation damage. We review our experimental results, discuss the fundamental limits of this technique and future plans.Comment: 7 pages, 8 figure

High energy Scattering in 2+1 QCD: A Dipole Picture

A dipole picture of high energy scattering is developed in the 2+1 dimensional QCD, following Mueller. A generalized integral equation for the dipole density with a given separation and center of mass position is derived, and meson-meson non-forward scattering amplitude is therefore calculated. We also calculate the amplitude due to two pomeron exchange, and the triple pomeron coupling. We compare the result obtained by this method to our previous result based on an effective action approach, and find the two results agree at the one pomeron exchange level.Comment: minor typos corrected. Postscript files are available through anonymous ftp quark.het.brown.edu, in the directory /pub/preprints, file name is 9407299. Hard copy is available upon reques

Cost-Aware Optimisation of Cache Allocation for Information-Centric Networking

This is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.Information-centric networking (ICN) is an emerging paradigm that decouples content from the host to achieve fast and cost-efficient communication and content distribution in the future Internet. A key feature of ICN is the deployment of ubiquitous in-network caching to speed up service delivery and improve network resource utilisation. ICN caching has been widely studied in terms of caching strategies and caching performance. However, the economic aspect of ICN has received marginal consideration so far, although it is vital to understand the potential cost-efficiency of ICN before its wide deployment in service provider network. To address this issue, we propose a cost-aware caching scheme to study the Quality-of-Service (QoS) and cost of ICN and investigate the inner association between them. Two new models are designed to characterise the cost and QoS of ICN with arbitrary topology under heterogeneous bursty content requests. A multi-objective evolution algorithm is adopted to find the optimal cache resource allocation. Numerical results show the effectiveness of the proposed scheme in achieving cost-efficiency and QoS guarantee in ICN caching

Performance evaluation of information-centric networking for multimedia services

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.The rapid development in multimedia services has shifted the major function of the current Internet from host-centric communication to service-oriented content dissemination. Motivated by this significant change, Information-Centric Networking (ICN) has emerged as a new networking paradigm, which aims at providing natural support for efficient information retrieval over the Internet. As a crucial characteristic of ICN, in-network caching enables users to efficiently access popular content from ubiquitous caches to improve the Quality-of-Experience (QoE). Therefore, in-network caching for ICN has received considerable attention in recent years and many cache schemes and models have been proposed. However, there is a lack of research into ICN cache models under practical environments such as arbitrary topology and multimedia services exhibiting bursty nature. To bridge the gap, this paper proposes a new analytical model to gain valuable insight into the caching performance of ICN with arbitrary topology and bursty content requests. The accuracy of the proposed model is validated by comparing the analytical results with those obtained from simulation experiments. The analytical model is then used as a cost-efficient tool to investigate the impact of key network and content parameters on the performance of caching in ICN

Effect of CeO2 addition on hardness of induction heated Ni-WC composite coatings

Getting Ni-WC composite coatings with different rare earth CeO2 additions on the substrate of 45 steel by induction heating; testing the surface hardness and cross-section microhardness of the coatings with Rockwell hardness tester and microhardness tester; meanwhile analyzing the microstructure and WC morphology of the coatings by scanning electron microscopy (SEM), in order to find the best amount of CeO2 in the coatings. The results show that the 0,5 / % content of CeO2 helps to improve the interfusion bonding between the coating and the substrate, and to refine the grain size, homogenize the composition and increase the hardness of the coating

Effect of CeO2 addition on wear, corrosion and resistance to thermal fatigue of induction heating Ni-WC coatings

Ni-WC composite coatings with different rare earth CeO2 additions were prepared on the substrate of 45 steel by induction heating. The wear resistance, corrosion resistance and resistance to thermal fatigue of the coating were checked with a self-made friction and wear tester, a medium-sized salt spray corrosion tank and a box-type resistance furnace. Meanwhile, the microstructure and WC morphology of each coating were analyzed by scanning electron microscopy to assist in the analysis of performance changes. The results show that the 0,5 / % CeO2 content helps to refine the grain size and the WC morphology, and that the 0,5 / % CeO2 content coating has the highest wear resistance, corrosion resistance and resistance to thermal fatigue