A new method for the synthesis of tridymite is reported in this article. When amorphous SiO
2
is treated with ethylene glycol for 3 h at 196°C and then filtered and washed with distilled water, ...tridymite is obtained. The transmission electron microscopy equipped with energy-dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) are used to characterize the crystal materials. The EDX shows the material is pure silica and The XRD pattern shows this silica is tridymite phase. In order to study the formation process of tridymite, all sorts of reaction conditions are discussed in detail. The products obtained at different conditions are characterized by XRD techniques. Finally, a reasonable mechanism is proposed.
Since planar graphics can not meet the needs of precisely reflecting real spatial relationship between pipelines, it is necessary to build a 3D visualization system of urban pipe network. 3D spatial ...data model is the basis of data representation and spatial visualization. Based on the analysis of the features of urban pipe network and the requirements of the 3D model, a spatial data model for urban pipe network visualization system (UPNVS) is designed and organized by spatial metadata. The advantage of the spatial metadata is discussed in the paper. The application of the model in a real project shows that it is effective.
Urban pipe network pipelines are criss-crossing and have 3D (three-dimension) distribution. Plenty of attribute information and spatial data are involved. In order to display it in a more intuitive ...way, UPNVS (urban pipe network visualization system) is designed. The thematic maps service is a part of it. In this paper, we propose the thematic maps service, upload and edit data service, information attention service and 3D viewing service. While 3D display service concentrates on displaying simple map and unique value map. It implements the transit from 2D thematic maps to 3D and reflects the different property values of pipelines with different colors. This application enhances thematic maps service lively and visibility. Finally, we plug it to our UPNVS which can show the patterns and trends easily and provide the information for decision-making. At the same time, the results can also be applied to other visualization system and 3D thematic maps.
This paper studies the functional services of the 3D visualization of urban pipe network (UPN). In accordance with the characteristics of the UPN and its demands for 3D visualization. The division of ...the visualization services of the 3D visualization of UPN is researched, then a structure of services division named service stack is propose in this paper, which is applicable to the 3D visualization of UPN. The service stack provides a unified standard for the development of the 3D visualization of UPN, simplifies the process of the system development, and provides the system with good compatibility, scalability and reusability. Key technologies about the service stack are also discussed in this paper. Finally, based on the service stack, a prototype of urban pipe network 3D visualization system is implemented.
A novel method, i.e. multi-cyclic quenching and partitioning （M-Q-P） heat treatment, is used to tailor the content of retained austenite （RA） in commercial steels. For 35CrMnSi steel, 5 times of Q-P ...heat treatment can increase the content of RA from 8 vol. % to 17 vol. %. As a result, the ultimate elongation of the steel is improved from 17.4% after the typical Q-P heat treat- ment to 27.1% after 5 times of Q-P treatment. Meanwhile, the improved combination of strength and ductility for steels by typical Q-P heat treatment is retained by the multi-cyclic Q-P heat treatment. It is shown that the content of RA in some spe- cific steels, and furthermore their mechanical properties, can be regulated through the M-Q-P.
Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and ...sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite （magnetite）, showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit.
•A novel BICPV smart window was designed for electricity generation and daylighting control.•HPC based thermotropic membrane was selected for the proposed BICPV smart window.•A validated ray-tracing ...program was used to predict the BICPV performance.•The BICPV offers higher electricity generation than its counterpart non-concentrating BIPV.
Building Integrated Concentrating Photovoltaic (BICPV) window represents a promising alternative approach for improving the electricity generation of photovoltaic cells when integrated into building windows. As a new concept, BICPV smart window consisting of an optically switchable thermotropic layer with integrated PV cells offers the potential to simultaneously generate electricity and control solar heat and visible light into buildings. In this study, a BICPV smart window system with a Hydroxypropyl Cellulose (HPC) based thermotropic hydrogel membrane has been developed and characterised. The system was designed with the aid of a validated wavelength-dependent optical model based on a Monte-Carlo ray-tracing technique, where the thermal and optical properties of the thermotropic layer used for the optical model prediction were obtained from experimental measurement. Subsequently, a prototype of the BICPV smart window system has been fabricated and characterised under controlled indoor conditions. From the experiments, it was found that the maximum power output of the BICPV smart window (6 wt% HPC) increases by 17.1% with the membrane temperature increasing from 40 °C (the transition temperature) to 54 °C; meanwhile, a 70.9% reduction in the light transmittance is observed. This indicated that the BICPC smart window might potentially reduce the solar heat gain in hot periods and therefore reduce the building energy demand. In addition, the effect of different concentrations of HPC polymer (2, 4 and 6 wt%) on the electrical and optical performance of the system has been investigated.
Adaptive control of solar heat gain and visible light transmission through windows is perceived to be a potential measure for enhancing energy conservation and visual comfort in buildings. In this ...study, a novel versatile window, named Building Integrated Photovoltaic (BIPV) smart window, was proposed to offer simultaneous improvement of daylighting control, on-site electricity generation and building energy efficiency, compared to traditional BIPV windows with static optical properties. The key components of the proposed system include an optically switchable thermotropic layer made of Hydroxypropyl Cellulose (HPC) hydrogel, crystalline-silicon photovoltaic cells, clear glass and low-emissivity (low-e) glass covers. The thermotropic layer can respond to heat by autonomously changing its visible and near-infrared optical properties, with which the amount of solar radiation into building spaces can be manipulated and thus the risks of excessive solar heating and illumination can be prevented. Apart from excellent solar modulation, the BIPV smart window can collect a proportion of the light scattered from the thermotropic layer and concentrate it onto the integrated PV cells for extra electricity generation. An innovative methodology has been proposed to predict the optical, thermal and electrical properties of the BIPV smart window under varying ambient conditions. Numerical simulations have been carried out in EnergyPlus to predict the window's performance when it is applied to an office-type environment in the climate of Nottingham, the UK. The influence of different window design scenarios, in terms of Window-to-Wall Ratio (WWR), orientation and transition temperature, has been investigated. It was found that using the BIPV smart window can achieve an annual energy saving of 36.6% but also a more comfortable indoor luminous environment, compared to the counterpart BIPV window (with no thermotropic layer integrated), when installed in the south-oriented office with a WWR of 25%.
•A novel BIPV window system with variable visible light and solar transmittance is proposed.•Numerical methods for modelling the proposed system are provided.•The designed system offers better energy and daylighting performance than conventional BIPV glazing and low-e double glazing.
•A switchable photovoltaic window based on thermotropic hydrogel is developed.•Selected hydrogel can reversibly switch between highly transmissive and scattering states.•The window performance is ...evaluated by indoor and outdoor experiments.•This window can passively control daylighting and heat gain during hot sunny days.•This window offers better electrical performance than conventional PV glazing.
Daylighting control technologies have become an essential part of sustainable building design to reduce overheating, glare and energy consumption in buildings. In this paper, a smart glazing system where a Building Integrated Photovoltaic (BIPV) glazing is coupled with an optically switchable thermotropic hydrogel layer is proposed to improve the daylighting control and electricity generation performance of traditional BIPV glazings. Thermotropic (TT) hydrogels made of various weight percentage combinations of hydroxypropyl cellulose (HPC) polymer, gellan gum and sodium chloride (NaCl) salt were synthesised and first evaluated by visible-near-infrared spectroscopy. Subsequently, small-scale prototypes of the proposed BIPV thermotropic (BIPV-TT) laminated glazing based on these TT hydrogels were fabricated and characterised experimentally under controlled laboratory conditions. The TT hydrogel, which was synthesised of 6 wt% HPC, 0.5 wt% gellan gum and 4.5 wt% NaCl, was selected for further experimental characterisations in a dynamic outdoor environment, due to its appropriate transition temperature of 30.7 °C for use in mild climates with a wide modulation range of solar transmittance from 85.8% (in the transparent state) to 9.6% (in the light-scattering state). The outdoor tests were conducted in Nottingham, the UK, on typical summer days with sunny and partial cloudy conditions. The results showed that using the prototype BIPV-TT laminated glazing can reduce up to 80% of the solar radiation transmitted into the outdoor test cell, while providing up to 12% higher electrical power outputs, compared to its counterpart system with no thermotropic hydrogel applied.
Building Integrated Photovoltaic (BIPV) glazings are promising technologies with the benefits of electricity generation, solar shading and building energy savings. A new approach is to integrate BIPV ...windows with thermotropic materials such as Hydroxypropyl Cellulose (HPC) hydrogel, which offers adaptive advantages for the systems to respond to time-varying weather conditions but also enhances the PV electricity generation. To design such systems, knowledge of the temperature-dependent scattering properties of the selected thermotropic materials is of significance. In this study, a Building Integrated Photovoltaic (BIPV) smart window system consisting of a thermotropic membrane synthesised using HPC and gellan gum gelling agent for electricity generation and also solar control has been designed and investigated. An advanced optical model, which combines a Monte-Carlo ray-tracing technique with an Inverse Adding-Doubling (IAD) method, has been developed for characterising the thermotropic membrane in terms of angular scattering distribution under various membrane temperatures and HPC concentrations. Then the developed optical model has been validated by comparison with experimental measurements. Subsequently, the validated optical model has been used to design and optimise the proposed BIPV smart window. The effects of HPC concentration, geometric concentration ratio, thermotropic membrane thickness and glass refractive index on PV power outputs have been evaluated. Finally, a prototype of the BIPV smart window with a 6 wt% HPC membrane has been manufactured and tested under indoor conditions. From the experimental tests, it was found that the total transmittance of the double-pane glass sample with a 6 wt% HPC membrane layer decreases from approximately 90%to 14%, when the membrane temperature increases from 27 °C to 56 °C. The measured short-circuit current for the prototype BIPV smart window is up to 1.15 times higher than that of its counterpart system with a similar PV area but no membrane.
•To develop a prototype building integrated PV smart window.•To develop a novel optical model combining Monte-Carlo ray-trace with an IAD.•To moderate the solar radiation entering buildings.•BIPV smart window has a higher electricity generation than normal BIPV.
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