Creative use of BIPV materials: barriers and solutions

Inventive use of photovoltaic (PV) materials in architecture can be developed through use of PV in artworks. This is particularly important in increasing the uptake of building-integrated building-integrated photovoltaics (BIPV), by developing novel methods of combining and installing PV materials. Current examples of PV artwork and design are examined, from small to large scale, to assess the current design limitations. The design of two PV artworks is discussed in detail, including an artwork that uses the principle of the luminescent solar concentrator (LSC), to show the way in which design hurdles are discovered and overcome. Challenges range from difficulties in obtaining small quantities of PV materials; the balance between efficiency and artistic effect; through to technical and siting issues that an artist must address when designing a functional PV structure. Methods of overcoming these barriers are explored, including the use of lumogen dyes in encapsulant materials

Modeling and Lyapunov-designed based on adaptive gain sliding mode control for wind turbines

In this paper, modeling and the Lyapunov-designed control approach are studied for the Wind Energy Conversion Systems (WECS). The objective of this study is to ensure the maximum energy production of a WECS while reducing the mechanical stress on the shafts (turbine and generator). Furthermore, the proposed control strategy aims to optimize the wind energy captured by the wind turbine operating under rating wind speed, using an Adaptive Gain Sliding Mode Control (AG-SMC). The adaptation for the sliding gain and the torque estimation are carried out using the sliding surface as an improved solution that handles the conventional sliding mode control. Furthermore, the resultant WECS control policy is relatively simple, meaning the online computational cost and time are considerably reduced. Time-domain simulation studies are performed to discuss the effectiveness of the proposed control strateg

A silicone host for Lumogen dyes

Altering the encapsulant colour in photovoltaic (PV) modules is a straightforward way of achieving greater colour range whilst minimising additional cost in PV systems. Lumogen fluorescent, organic dyes offer a way of adding colour to the encapsulant with minimal change in efficiency. The silicone encapsulant material Sylgard 184 is tested as a host material for Lumogen dyes. A method of dissolving various Lumogen dyes in Sylgard is investigated, and limits of solubility are explored. Methods of preparing samples suitable for optical measurements are found. Optical density is measured for a range of dye concentrations. The results indicate that Lumogen dyes can be dissolved successfully within Sylgard 184, giving good optical properties for lower dye concentrations. Initial photoluminescent quantum yield measurements confirm that Lumogen dyes can function effectively within a Sylgard host. This is promising for use of this material combination in the creation of coloured, fluorescent PV encapsulant layers

The search for building-integrated PV materials with good aesthetic potential: a survey

Building-integrated photovoltaics (PV) is currently dominated by blue and black rectilinear forms. Greater variety of colour and form could lead to much better uptake of PV in the built environment, also increasing the potential for PV to be used as an artistic material. Listing the available PV technologies by colour gives a clearer picture of the current situation. An assessment of photostability, efficiency and price, for each material, indicates the materials that have the potential to fill the gaps in the colour spectrum. Use of combinations of materials that can be fabricated in different ways from the current, standardised, PV modules will further increase the possibilities for use in building integration, Extending the lifetimes of organic PV, dye-sensitised PV or luminescent solar concentrators will increase the possibilities for development of new PV products

Improving the aesthetics of photovoltaics through use of coloured encapsulants

Photovoltaics (solar cells) are important in the creation of sustainable architecture, but are difficult to integrate into a wide variety of architectural styles, which is necessary if this technology is to be extensively used. Adding variety to the colour range in these installations will provide a way of making this solar energy technology more visually exciting, so methods need to be found to add colour at minimal extra cost, without loss of efficiency. Adding colour to photovoltaic encapsulant materials offers a solution. It is shown that fluorescent, organic Lumogen dyes (BASF) can be added to the photovoltaic encapsulant materials Sylgard 184 (Dow Corning) and EVA (Ethylene Vinyl Acetate). The dyes continue to fluoresce within these host materials. Encapsulating a photovoltaic cell with Sylgard containing Lumogen red 300 dye (BASF) demonstrates that light can be transported to a photovoltaic cell by the fluorescent dyes inside the encapsulant material that surrounds the cell. This slightly improves the electricity output from the photovoltaic cell, and is especially promising for use in light-transmissive photovoltaic arrays incorporating widely-spaced photovoltaic cells, such as architectural glass art that incorporates photovoltaics. Further work is needed to test and improve the performance of the dyes over time, to ensure that installations incorporating this technology can last for the minimum twenty years that is the current industry standard for photovoltaics

Sveobuhvatan pregled LVRT mogućnosti i kliznog režima upravljanja vjetroagregata spojenog na mrežu s dvostruko napajanim asinkronim generatorom

In this paper, a comprehensive review of several strategies applied to improve the Low Voltage Ride-Through (LVRT) capability is presented for grid-connected wind-turbine-driven Doubly Fed Induction Generator (DFIG). Usually, the most proposed LVRT solutions in the literature based on: hardware solutions, which increase the system costs and software solutions, which increase the control system complexity. Therefore, the main objective of this study is to take into account grid requirements over LVRT performance under grid fault conditions using software solution based on Higher Order-Sliding Mode Control (HOSMC). Effectively, this control strategy is proposed to overcome the chattering problem and the injected stator current harmonics into the grid of the classical First Order Sliding Mode (FOSMC). Furthermore, the resultant HOSMC methodology is relatively simple; where, the online computational cost and time are considerably reduced. The LVRT capacity and effectiveness of the proposed control method, compared to the conventional FOSMC, are validated by time-domain simulation studies under Matlab on a 1.5 MW wind-turbine-driven DFIG.U ovom radu, prikazan je sveobuhvatan pregled strategija primjenjenih za poboljšanje sposobnosti rada tijekom prolaznih smetnji niskog napona mreže za vjetroagregat s dvostruko napajanim asinkronim generatorom (DFIG). Uobičajeno, većina predloženih LVRT rješenja u literaturi temelji se na: hardverskim rješenjima, što povećava troškove sustava i softverskih rješenja te složenost sustava upravljanja. Stoga je glavni cilj ovog istraživanja da se uključuje i zahtjevi mreže kroz ponašanje LVRTa u uvjetima mrežnih kvarova korištenjem softverskog rješenja zasnovanoga na kliznom režimu rada višeg reda (HOSMC). Efektivno, ova upravljačka strategija je predložena kako bi se prevladali oscilacije i ubacivanje harmonika struje statora u mrežu klasičnim metodama kliznog režima rada prvog reda (FOSMC). Nadalje, rezultantna metodologija HOSMC je relativno jednostavna; gdje su online računski zahtjevi i potrebno vrijeme značajno smanjeni. LVRT kapacitet i učinkovitost predložene metode upravljanja, u usporedbi s konvencionalnim FOSMC potvrđene su simulacijama u vremenskoj domeni u Matlabu na 1.5 MW vjetroagregatu s DFIG-om

Ver-sur-Mer – British Normandy Memorial

Le projet de création d’un mémorial d’une surface de près de 18 ha à Ver-sur-Mer, au lieu-dit « Les Loges », a impliqué la prescription d’un diagnostic 7,8 ha correspondant à la surface réellement impactée. Les tranchées ont été ouvertes en fonction de la géographie du terrain, de l’axe des pentes mais également en fonction de la contrainte liée à l’environnement. Une opération de diagnostic contiguë, à l’ouest des parcelles AV 84 et 94, réalisée par une équipe du Service archéologie du Dépar..

Deep-Learning and Vibration-Based System for Wear Size Estimation of Railway Switches and Crossings

The switch and crossing (S&C) is one of the most important parts of the railway infrastructure network due to its significant influence on traffic delays and maintenance costs. Two central questions were investigated in this paper: (I) the first question is related to the feasibility of exploring the vibration data for wear size estimation of railway S&C and (II) the second one is how to take advantage of the Artificial Intelligence (AI)-based framework to design an effective early-warning system at early stage of S&C wear development. The aim of the study was to predict the amount of wear in the entire S&C, using medium-range accelerometer sensors. Vibration data were collected, processed, and used for developing accurate data-driven models. Within this study, AI-based methods and signal-processing techniques were applied and tested in a full-scale S&C test rig at Lulea University of Technology to investigate the effectiveness of the proposed method. A real-scale railway wagon bogie was used to study different relevant types of wear on the switchblades, support rail, middle rail, and crossing part. All the sensors were housed inside the point machine as an optimal location for protection of the data acquisition system from harsh weather conditions such as ice and snow and from the ballast. The vibration data resulting from the measurements were used to feed two different deep-learning architectures, to make it possible to achieve an acceptable correlation between the measured vibration data and the actual amount of wear. The first model is based on the ResNet architecture where the input data are converted to spectrograms. The second model was based on a long short-term memory (LSTM) architecture. The proposed model was tested in terms of its accuracy in wear severity classification. The results show that this machine learning method accurately estimates the amount of wear in different locations in the S&C

Field tests of fibre Bragg grating sensors incorporated into CFRP for railway bridge strengthening condition monitoring

The EU is in the process of upgrading the national railway networks to meet the demands from high-speed passenger trains and heavy Freight traffic. This upgrade necessitates a review of the development and implementation of novel technologies to repair and strengthen the existing bridge structures and to improve their performance. This paper presents the evaluation results of the use of FBG strains sensors incorporated in CFRP (carbon fibre reinforcement polymer) rods and tubes as part of the methodology for monitoring the performance of the NSMR (near surface mounted reinforcement) which is an essential part of the repair and strengthening of bridges. In addition, a new method has been tested for the first time using CFRP tubes which calls for the drilling of holes instead of sawing grooves in the installation process. The paper discusses in some detail the strengthening mechanism, FBG sensor implementation and the electronic system used to interrogate the FBG sensors. The results obtained from the monitoring show that FBG sensors can be integrated into CFRP and that reliable measurements can be made. However, in this particular project, the strain loading is very moderate so consequently the strain levels are in the elastic regime

Chemical Modification of Xylan

Our study is part of the general context of valuing by-products from the wood industry, which consists of the chemical modification of xylan by synthesis of branched copolymers such as xylan-g-PLLA. The used xylan is extracted from chestnut and 4-dimethylaminopyridine (DMAP) is the catalyst. In fact, the synthesis of xylan-graft-poly (L-lactide) copolymer starting from natural and renewable resource products xylan and L-lactide is performed under different conditions. The results of the grafting reaction are unfavorable due to longer time because of depolymerization reactions. Another result is the solubility and insolubility of the copolymers synthesized in water. This first result indicates that there is a change in the properties of xylan. Moreover, the solubility of the xylan-g-PLLA copolymers is different from one study to another. Grafting of PLLA onto xylan was confirmed by Fourier transform infrared (FT-IR) and 1HNMR analyzes. The dynamic mechanical analysis showed that the xylan-g-PLLA plastic materials have interesting thermomechanical properties