Fano-Rashba effect in thermoelectricity of a double quantum dot molecular junction

We examine the relation between the phase-coherent processes and spin-dependent thermoelectric effects in an Aharonov-Bohm (AB) interferometer with a Rashba quantum dot (QD) in each of its arm by using the Green's function formalism and equation of motion (EOM) technique. Due to the interplay between quantum destructive interference and Rashba spin-orbit interaction (RSOI) in each QD, an asymmetrical transmission node splits into two spin-dependent asymmetrical transmission nodes in the transmission spectrum and, as a consequence, results in the enhancement of the spin-dependent thermoelectric effects near the spin-dependent asymmetrical transmission nodes. We also examine the evolution of spin-dependent thermoelectric effects from a symmetrical parallel geometry to a configuration in series. It is found that the spin-dependent thermoelectric effects can be enhanced by controlling the dot-electrode coupling strength. The simple analytical expressions are also derived to support our numerical results

Thermoelectric properties of Al-doped mesoporous ZnO thin films

Al-doped mesoporous ZnO thin films were synthesized by a sol-gel process and an evaporation-induced self-assembly process. In this work, the effects of Al doping concentration on the electrical conductivity and characterization of mesoporous ZnO thin films were investigated. By changing the Al doping concentration, ZnO grain growth is inhibited, and the mesoporous structure of ZnO is maintained during a relatively high temperature annealing process. The porosity of Al-doped mesoporous ZnO thin films increased slightly with increasing Al doping concentration. Finally, as electrical conductivity was increased as electrons were freed and pore structure was maintained by inhibiting grain growth, the thermoelectric property was enhanced with increasing Al concentration. © 2013 Min-Hee Hong et al

A dynamic model for nozzle clog monitoring in fused deposition modelling

© Emerald Publishing Limited. Purpose - Fused deposition modelling (FDM) is one of the most popular additive manufacturing processes, and is widely used for prototyping and fabricating low-cost customized parts. Current FDM machines have limited techniques to monitor process conditions to minimize process errors, such as nozzle clogging. Nozzle clogging is one of the most significant process errors in current FDM machines, and may cause serious consequences such as print failure. This paper aims to present a physics-based dynamic model suitable for monitoring nozzle clogging in FDM machines. Design/methodology/approach - Liquefier mount of an FDM extruder is analysed as a beam excited by a uniform loading distributed over a partial length. Boundary conditions and applied loads for a direct-type FDM extruder are identified and discussed. Simulation of nozzle clogging was performed by using nozzles of different diameters from 0.5 to 0.2 mm, in step change of 0.1 mm. Sets of experiments were carried out by measuring vibrations of the liquefier block mount during FDM extrusion. Findings - The mount of a liquefier block in an FDM extruder can be used to place a vibration sensor to monitor process errors such as nozzle clogging. Liquefier block mount's transverse vibration amplitudes increase non-linearly when nozzle starts to block. Practical implications - The proposed model can be effectively used for monitoring nozzle clogging in FDM machines, as it is based on the physics relating the FDM process parameters and the nozzle blockage. Originality/value - The novelty of this paper is the unique method of modelling the FDM process dynamics that can be used for monitoring nozzle clogging

Effect of surfactant concentration variation on the thermoelectric properties of mesoporous ZnO

The electrical and thermal conductivities and the Seebeck coefficient of mesoporous ZnO thin films were investigated to determine the change of their thermoelectric properties by controlling surfactant concentration in the mesoporous ZnO films, because the thermoelectric properties of mesoporous ZnO films can be influenced by the porosity of the mesoporous structures, which is primarily determined by surfactant concentration in the films. Mesoporous ZnO thin films were successfully synthesized by using sol-gel and evaporation-induced self-assembly processes. Zinc acetate dihydrate and Brij-76 were used as the starting material and pore structure-forming template, respectively. The porosity of mesoporous ZnO thin films increased from 29% to 40% with increasing surfactant molar ratio. Porosity can be easily altered by controlling the molar ratio of surfactant/precursor. The electrical and thermal conductivity and Seebeck coefficients showed a close correlation with the porosity of the films, indicating that the thermoelectric properties of thin films can be changed by altering their porosity. Mesoporous ZnO thin films with the highest porosity had the best thermoelectric properties (the lowest thermal conductivity and the highest Seebeck coefficient) of the films examined. © 2013 Min-Hee Hong et al

VIABILITY, FATTY ACID COMPOSITION, AND STRUCTURE OF THE CORALLINE ALGA CORALLINA PILULIFERA

The decrease in the seaweed flora in some rocky areas, known as algal whitening or barren ground, is associated with some species of coralline algae. To determine the biological characteristics of a representative species of branched coralline alga, the number of medullary tiers was counted and ranged from 12 to 16. The 18S rDNA, psbA, and rbcL genes were used to confirm the identification of Corallina pilulifera. Measuring viability using triphenyl tetrazolium chloride showed highly viability from December to January. Cultural conditions of 16 C, 16 h light:8 h dark cycle, and 40 mu E m(-2) s(-1) light intensity were optimal for maintaining the viability of the coralline alga for up to three days. The fatty acids included 31.4% omega-3 eicosapentaenoic acid. Scanning electron microscopy of the surface structure revealed unique round wells about 7.9 +/- 1.3 mu m in diameter. The coralline alga, preventing fleshy seaweeds, may be used as a potential template for the creation of new environmentally friendly biomimetic antifouling material against the attachment of soft foulants, especially micro- and macroalgae.X111Ysciescopu

Tackling nitric oxide emissions from dominant diesel vehicle models using on-road remote sensing technology

© 2018 Elsevier Ltd Remote sensing provides a rapid detection of vehicle emissions under real driving condition. Remote sensing studies showed that diesel nitrogen oxides emissions changed little or were even increasing in recent years despite the tightened emission standards. To more accurately and fairly evaluate the emission trends, it is hypothesized that analysis should be detailed for individual vehicle models as each model adopted different emissions control technologies and retrofitted the engine/vehicle at different time. Therefore, this study was aimed to investigate the recent nitric oxide (NO) emission trends of the dominant diesel vehicle models using a large remote sensing dataset collected in Hong Kong. The results showed that the diesel vehicle fleet was dominated by only seven models, accounting for 78% of the total remote sensing records. Although each model had different emission levels and trends, generally all the dominant models showed a steady decrease or stable level in the fuel based NO emission factors (g/kg fuel) over the period studied except for BaM1 and BdM2. A significant increase was observed for the BaM1 2.49 L and early 2.98 L models during 2005–2011, which we attribute to the change in the diesel fuel injection technology. However, the overall mean NO emission factor of all the vehicles was stable during 1991–2006 and then decreased steadily during 2006–2016, in which the emission trends of individual models were averaged out and thus masked. Nevertheless, the latest small, medium and heavy diesel vehicles achieved similar NO emission factors due to the converging of operation windows of the engine and emission control devices. The findings suggested that the increasingly stringent European emission standards were not very effective in reducing the NO emissions of some diesel vehicle models in the real world. The European emission regulations were not very effective in reducing the NO emissions from some diesel vehicle models in the real world

A micromechanical model for deformation behavior of nanocrystalline copper

Molecular dynamics simulations have show that nanocrystalline (NC) materials can be treated as composite materials consisting of two phases of grain and grain boundary. In this paper, the incremental stress-strain relation is derived based on deformation mechanism of NC materials and internal variable theory from micromechanics point of view. The developed model is exemplified by the pure copper subjected to uniaxial tension. Implicated iteration algorithm is then employed to obtain the stress-strain relation. Moreover, the effects of grain shape and statistical distribution of grain sizes are also discussed, and predicted results are compared with experimental values to verify the model

A geographical information system for marine management and its application to Xiamen Bay, China

Use of GIS (geographical information systems) is an effective and efficient method for gathering and processing large quantities of marine data, such as three-dimensional (3-D) time series of velocity vectors and suspended sediment and pollutant concentrations, and for visual display for result interpretation. A MGIS (marine geographical information system) has been developed for Xiamen Bay and other coastal regions in China. The system can handle object spatial property and a variety of data formats. Besides the standard data manipulation, plotting, and retrieval functions of GIS, two hydrodynamic/mass-transport numerical models for tidal flows, sediment transport, and pollutant dispersion have also been incorporated into the MGIS. Most of the modeling pre- and post-processing operations can be finished within the system. The pre-processing includes mesh generation, gathering of boundary and parallel computation information. The post-processing includes result posting, plotting and analysis. The MGIS has been implemented for more than three years and proven to be a useful integrated tool for generating and revealing various kinds of marine environmental information. Output from the MGIS may provide an important tool for harbor management, and feasibility or environmental impact assessment studies for new coastal structures. The system can be easily adopted in other marine areas through loading new databases and re-verifying the numerical model in the new domain

Using Chinese Version of MYMOP in Chinese Medicine Evaluation: Validity, Responsiveness and Minimally Important Change

<p>Abstract</p> <p>Background</p> <p>Measure Yourself Medical Outcome Profile (MYMOP) is a patient generated outcome instrument applicable in the evaluation of both allopathic and complementary medicine treatment. This study aims to adapt MYMOP into Chinese, and to assess its validity, responsiveness and minimally important change values in a sample of patients using Chinese medicine (CM) services.</p> <p>Methods</p> <p>A Chinese version of MYMOP (CMYMOP) is developed by forward-backward-forward translation strategy, expert panel assessment and pilot testing amongst patients. 272 patients aged 18 or above with subjective symptoms in the past 2 weeks were recruited at a CM clinic, and were invited to complete a set of questionnaire containing CMYMOP and SF-36. Follow ups were performed at 2^ndand 4^thweek after consultation, using the same set of questionnaire plus a global rating of change question. Criterion validity of CMYMOP was assessed by its correlation with SF-36 at baseline, and responsiveness was evaluated by calculating the Cohen effect size (ES) of change at two follow ups. Minimally important difference (MID) values were estimated via anchor based method, while minimally detectable difference (MDC) figures were calculated by distribution based method.</p> <p>Results</p> <p>Criterion validity of CMYMOP was demonstrated by negative correlation between CMYMOP Profile scores and all SF-36 domain and summary scores at baseline. For responsiveness between baseline and 4^thweek follow up, ES of CMYMOP Symptom 1, Activity and Profile reached the moderate change threshold (ES>0.5), while Symptom 2 and Wellbeing reached the weak change threshold (ES>0.2). None of the SF-36 scores reached the moderate change threshold, implying CMYMOP's stronger responsiveness in CM setting. At 2^ndweek follow up, MID values for Symptom 1, Symptom 2, Wellbeing and Profile items were 0.894, 0.580, 0.263 and 0.516 respectively. For Activity item, MDC figure of 0.808 was adopted to estimate MID.</p> <p>Conclusions</p> <p>The findings support the validity and responsiveness of CMYMOP for capturing patient centred clinical changes within 2 weeks in a CM clinical setting. Further researches are warranted (1) to estimate Activity item MID, (2) to assess the test-retest reliability of CMYMOP, and (3) to perform further MID evaluation using multiple, item specific anchor questions.</p