A new experience mining approach for improving low carbon city development

Developing low carbon city (LCC) has been widely appreciated as an important strategy for sustainable development. In line with this, an increasing number of cities globally have launched low carbon practices in recent years and gained various types of experience. However, it appears that existing studies do not present methods of how to use these valuable LCC experience in solving new problems. This study therefore introduces an experience mining approach to assist decision‐makers in reusing previous experience when tailoring LCC development strategies. The mining approach consists of three processes, namely, collecting historical cases which have been experiencing LCC, establishing LCC experience base, and mining similar experience cases. This study innovates the existing experience mining approach by introducing a two‐step mining process with considering the perspective of problem‐based urban characteristics (PBUCs) and the perspective of solution‐based urban characteristics (SBUCs). The application of the introduced mining approach has been demonstrated by a case study, where Shenyang’s energy structure is adopted as the target problem. The new experience mining approach provides a valuable reference for decision‐makers to retrieve similar cases for improving LCC development with the consideration of city characteristics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/156189/2/sd2046_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/156189/1/sd2046.pd

Renewable Chemicals: Dehydroxylation of Glycerol and Polyols

The production of renewable chemicals is gaining attention over the past few years. The natural resources from which they can be derived in a sustainable way are most abundant in sugars, cellulose and hemicellulose. These highly functionalized molecules need to be de-functionalized in order to be feedstocks for the chemical industry. A fundamentally different approach to chemistry thus becomes necessary, since the traditionally employed oil-based chemicals normally lack functionality. This new chemical toolbox needs to be designed to guarantee the demands of future generations at a reasonable price. The surplus of functionality in sugars and glycerol consists of alcohol groups. To yield suitable renewable chemicals these natural products need to be defunctionalized by means of dehydroxylation. Here we review the possible approaches and evaluate them from a fundamental chemical aspect

Removal of concentrated sulfamethazine by acclimatized aerobic sludge and possible metabolic products

This article examined the biological removal of high concentrated sulfamethazine (SMZ) antibiotics by the acclimatized activated sludge in lab-scale SBRs system. The removal of SMZ was characterized by a quick adsorption and a slow process of biodegradation. The adsorption capacity of activated sludge for SMZ was 44 and 47 µg SMZ/g SS, respectively, with the initial SMZ concentrations of 1 and 2 mg/L. The adsorption process fitted pseudo-second-order kinetic model. In a series of batch studies, with the increase of initial SMZ concentration that were 1, 2, 3, 5, 7 and 9 mg/L, 56.0%, 51.3%, 42.2%, 29.5%, 25.0% and 20.8% of influent SMZ were biodegraded within 24 h of biological reaction, respectively. The Monod equation applied to simulate SMZ biodegradation had a good coefficient of determination (R2 > 0.99). Furthermore, the results of HPLC demonstrated that the SMZ was not completely removed by the acclimatized activated sludge. From the analysis of LC-MS, 4 intermediates of SMZ biodegradation were identified: Sulfanilic Acid, 4-amino-N-(4,6-dimethyl-2 pyrimidin) benzene sulfonamide, N-(4,6-dimethyl-2-pyrimidin)-4-N-(benzene sulfonamide) benzene sulfonamide, N-(4,6-dimethyl-2-pyrimidin)-4-N-(4,6-dimethyl pyrimidine) benzene sulfonamide, and N-(4,6-dimethyl-2-pyrimidin)-4-N-(3-dimethyl-4-N sodium benzene sulfonamide) benzene sulfonamide.Published versio

Opportunistic Cognitive Relaying: A Win-Win Spectrum Sharing Scheme

<p/> <p>A cost-effective spectrum sharing architecture is proposed to enable the legacy noncognitive secondary system to coexist with the primary system. Specifically, we suggest to install a few intermediate nodes, namely, the cognitive relays, to conduct the spectrum sensing and coordinate the spectrum access. To achieve the goal of win-win between primary and secondary systems, the cognitive relay may act as a cooperator for both of them, and an <it>Opportunistic Cognitive Relaying</it> (OCR) scheme is specially devised. In this scheme, the cognitive relay opportunistically switches among three different working modes, that is, <it>Relay for Primary Link</it> (RPL), <it>Relay for Secondary Link</it> (RSL), or <it>Relay for Neither of the Links</it> (RNL), respectively, based on the channel-dependent observation of both systems. In addition, the transmit power for cognitive relay and secondary transmitter in each mode are optimally determined by maximizing the transmission rate of secondary system while keeping or even reducing the outage probability of primary system. Simulation results validate the efficiency of the proposed spectrum sharing scheme.</p

Opportunistic Cognitive Relaying: A Win-Win Spectrum Sharing Scheme

A cost-effective spectrum sharing architecture is proposed to enable the legacy noncognitive secondary system to coexist with the primary system. Specifically, we suggest to install a few intermediate nodes, namely, the cognitive relays, to conduct the spectrum sensing and coordinate the spectrum access. To achieve the goal of win-win between primary and secondary systems, the cognitive relay may act as a cooperator for both of them, and an Opportunistic Cognitive Relaying (OCR) scheme is specially devised. In this scheme, the cognitive relay opportunistically switches among three different working modes, that is, Relay for Primary Link (RPL), Relay for Secondary Link (RSL), or Relay for Neither of the Links (RNL), respectively, based on the channel-dependent observation of both systems. In addition, the transmit power for cognitive relay and secondary transmitter in each mode are optimally determined by maximizing the transmission rate of secondary system while keeping or even reducing the outage probability of primary system. Simulation results validate the efficiency of the proposed spectrum sharing scheme