Evacuated glazing with tempered glass

The application of tempered glass has made it possible to significantly reduce the support pillar number within evacuated glazing (EG) since tempered glass (T-glass) is four to ten times mechanically stronger than annealed glass (A-glass). The thermal transmittance (U-value) of 0.4 m by 0.4 m double evacuated glazing (DEG) with 4 mm thick T-glass and A-glass panes with emittance of 0.03 were determined to be 0.3 Wm−2K−1 and 0.57 Wm−2K−1, respectively (47.4% improvement) using previously experimentally validated finite volume model. The thermal transmittance (U-value) of 0.4 m by 0.4 m triple evacuated glazing (TEG) with 4 mm thick T-glass and A-glass panes with emittance of 0.03 were determined to be 0.11 Wm−2K−1 and 0.28 Wm−2K−1, respectively (60.7% improvement). The improvement in the U-value of EG with T-glass is due to a reduction in support pillar number, leading to reduction in heat conduction through pillar array. The impact of tempered glass on the thermal transmittance for TEG is greater than that of DEG since radiative heat transfer in TEG is much lower than that in DEG, thus the reduction in heat conduction resulted from the reduction of support pillar number in TEG is much larger than that in DE

Groups generated by two elliptic elements in PU(2,1)

Let $f$ and $g$ be two elliptic elements in $\mathbf{PU}(2,1)$ of order $m$ and $n$ respectively, where $m\geq n>2$. We prove that if the distance $\delta(f,g)$ between the complex lines or points fixed by $f$ and $g$ is large than a certain number, then the group $$ is discrete nonelementary and isomorphic to the free product $\mathbf{Z}_{m}*\mathbf{Z}_{n}$.Comment: 9 page

The influence of low-temperature surface induction on evacuation, pump-out hole sealing and thermal performance of composite edge-sealed vacuum insulated glazing

Hermeticity of vacuum edge-sealing materials are one of the paramount requirements, specifically, to the evolution of energy-efficient smart windows and solar thermal evacuated flat plate collectors. This study reports the design, construction and performance of high-vacuum glazing fabrication system and vacuum insulated glazing (VIG). Experimental and theoretical investigations for the development of vacuum edgeseal made of Sn-Pb-Zn-Sb-AlTiSiCu composite in the proportion ratio of 56:39:3:1:1 by % (CS-186) are presented. Experimental investigations of the seven constructed VIG samples, each of size 300mm·300mm·4 mm, showed that increasing the hot-plate surface temperatures improved the cavity vacuum pressure whilst expediting the pump-out hole sealing process but also increases temperature induced stresses. Successful pump-out hole sealing process of VIG attained at the hot-plate set point temperature of 50˚C and the approximate cavity pressure of 0.042 Pa was achieved. An experimentally and theoretically validated finite volume model (FVM) was utilised. The centre-of-pane and total thermal transmittance values are calculated to be 0.91 Wm-2K-1 and 1.05 Wm-2K-1, respectively for the VIG. FVM results predicted that by reducing the width of vacuum edge seal and emissivity of coatings the thermal performance of the VIG is improved

Appropriate Models In Decision Support Systems For River Basin Management

In recent years, new ideas and techniques appear very quickly, like sustainability, adaptive management, Geographic Information System, Remote Sensing and participations of new stakeholders, which contribute a lot to the development of decision support systems in river basin management. However, the role of models still needs to be emphasized, especially for model-based decision support systems. This paper aims to find appropriate models for decision support systems. An appropriate system is defined as ‘the system can produce final outputs which enable the decision makers to distinguish different river engineering measures according to the current problem’. An appropriateness framework is proposed mainly based on uncertainty and sensitivity analysis. A flood risk model is used, as a part of the Dutch River Meuse DSS to investigate whether the appropriate framework works. The results showed that the proposed approach is applicable and helpful to find appropriate models

Rate Analysis of Two-Receiver MISO Broadcast Channel with Finite Rate Feedback: A Rate-Splitting Approach

To enhance the multiplexing gain of two-receiver Multiple-Input-Single-Output Broadcast Channel with imperfect channel state information at the transmitter (CSIT), a class of Rate-Splitting (RS) approaches has been proposed recently, which divides one receiver's message into a common and a private part, and superposes the common message on top of Zero-Forcing precoded private messages. In this paper, with quantized CSIT, we study the ergodic sum rate of two schemes, namely RS-S and RS-ST, where the common message(s) are transmitted via a space and space-time design, respectively. Firstly, we upper-bound the sum rate loss incurred by each scheme relative to Zero-Forcing Beamforming (ZFBF) with perfect CSIT. Secondly, we show that, to maintain a constant sum rate loss, RS-S scheme enables a feedback overhead reduction over ZFBF with quantized CSIT. Such reduction scales logarithmically with the constant rate loss at high Signal-to-Noise-Ratio (SNR). We also find that, compared to RS-S scheme, RS-ST scheme offers a further feedback overhead reduction that scales with the discrepancy between the feedback overhead employed by the two receivers when there are alternating receiver-specific feedback qualities. Finally, simulation results show that both schemes offer a significant SNR gain over conventional single-user/multiuser mode switching when the feedback overhead is fixed.Comment: accepted to IEEE Transactions on Communication

Control the high-order harmonics cutoff through the combination of chirped laser and static electric field

The high harmonic generation from atoms in the combination of chirped laser pulse and static field is theoretically investigated. For the first time, we explore a further physical mechanism of the significant extension of high harmonic generation cutoff based on three-step model. It is shown that the cutoff is substantially extended due to the asymmetry of the combined field. If appropriate parameters are chosen, the cutoff of high harmonic generation can reach Ip+42Up. Furthermore, an ultrabroad super-continuum spectrum can be generated. When the phases are properly compensated for, an isolated 9 attosecond pulse can be obtained.Comment: 7 pages 5figure