This paper presents a design of an intelligent remote electrical power supervisory control and data acquisition (SCADA) system based on the Internet of Things (IoT), with Internet Information Services (IIS) for setting up web servers, an ASP.NET model–view– controller (MVC) for establishing a remote electrical power monitoring and control system by using responsive web design (RWD), and a Microsoft SQL Server as the database. With the web browser connected to the Internet, the sensing data is sent to the client by using the TCP/IP protocol, which supports mobile devices with different screen sizes. The users can provide instructions immediately without being present to check the conditions, which considerably reduces labor and time costs. The developed system incorporates a remote measuring function by using a wireless sensor network and utilizes a visual interface to make the human–machine interface (HMI) more instinctive. Moreover, it contains an analog input/output and a basic digital input/output that can be applied to a motor driver and an inverter for integration with a remote SCADA system based on IoT, and thus achieve efficient power management.
The surface of cotton textile was modified to create a water-repellent finishing by depositing a modifying coatings using the sol-gel technique. Treated textiles evaluated using scanning electron microscopy, X-Ray powder diffraction (XRD). The wettability of treated fabrics was characterized by water contact angle and drop test. The results showed that the cotton textile treated with 7.5 wt.% zinc acetate dihydrate sol showed excellent hydrophobic properties, water contact angle could reach 145°C without decreasing after 50 hydrothermal treatment cycles.
In the present work formation of active TiO2 nanoparticles in microwave synthesis and their modification with platinum were studied. Anatase nanopowder and 10 M KOH solution were used as raw materials. Microwave assisted synthesis method permited to obtain TiO2 nanofibres and nanowires with a diameter of 10 nm and a specific surface area in the range of 70 – 150 m2/g. In order to modify TiO2 nanofibers with platinum it was stirred in H2PtCl6 solution under UV irradiation. Photocatalytic activity was determined by degradation of the methylene blue (MB) solution under UV and visible light irradiation. The obtained samples showed higher photocatalytic activity with respect to pure TiO2 nanofibers. The doped TiO2 nanofibers were appropriate for degradation of harmful organic compounds as well as for hydrogen production by water splitting.
We present a simple electrochemical method, called intercalation spectroscopy, to study the electronic density-of-states of intercalation materials. It is based on the realization that electrochemical quasi-steady state potential curves of a number of materials exhibit fine structure in good agreement with features in the density of electronic states. Different electrochemical techniques are able to give this information, but chronopotentiometry appears to have advantages from an experimental viewpoint. In this paper we compare the so called 'electrochemical density-of-states' of amorphous and crystalline structures. We also address the limitations of intercalation spectroscopy due to kinetic effects, i.e. very slow relaxations of the charge carriers. Intercalation spectroscopy is in principle very sensitive, although in limited energy ranges, and is able to give information complementary to electron and x-ray spectroscopies for a number of materials.
Inverse opals are photonic band gap (PBG) structures with a periodic arrangement of voids with low refractive index (air) in a high-refractive index dielectric media with sub-wavelength periodicity. In analogy with electronic band gaps in solid state semiconductors these structures form forbidden energy ranges for light, irrespective of the photon’s momentum. Recently, inverse opal structures have been studied for photocatalysis applications. Here the idea is to match the edge of the PBG with the electronic band gap of a semiconductor to allow for efficient light absorption. Here we present a novel approach to tune the position and shape of the PBG by purposefully deposit multilayers of oxides with controlled thicknesses on the inside walls of the inverse opals. This avoids the technical problems of changing the periodicity and materials of the opals. The fabrication involves a three-step process: It consists of self-assembly by convective evaporation of polystyrene beads into close-packed fcc structures; atomic layer deposition (ALD) of metal oxides (Al2O3) to fill the voids between the beads; and subsequent Ar ion etching and calcination to crystallize and develop the inverse opal structure. ALD is then repeated to make multi-layer structures of TiO2 with controlled thickness. The inverse opal structures were characterized by optical spectroscopy, X-ray spectroscopy, electron microscopy, and profilometry. Theoretical modeling was performed to describe the optical properties. The results are analyzed and compared with band structure calculations made by the plane-wave expansion method together with finite-difference time-domain simulations of the transmission spectra (Fig. 1). Our method is versatile and can be used to fabricate reactive nanoparticles with different chemical composition on the inside walls; as well as plasmonic nanoparticles embedded in the layers to efficiently absorb slow light.
As a feasible option for photovoltaic technology to meet the growing energy demand, dye-sensitized solar cells (DSSCs) have attracted much attention due to their low cost, ease of fabrication and good performance. Their relevant technological drawbacks are poor long-term stability, difficulty in robust and hermetic sealing, electrolyte evaporation/leakage, and permeability to H2O/O2. These problems can be solved replacing the traditional liquid electrolyte (I-/I3-/CH3CN) with gel-polymer electrolytes or liquids solidified with gelators/nanoparticles In recent years, it has been verified that the best solution is to trap the liquid electrolyte in a polymer network, thus developing quasi-solid electrolytes capable of providing light-to-electricity conversion efficiencies around 3-5%. The advantage of these electrolytes is that they possess simultaneously the diffusive transport property, the high ionic conductivity and the interfacial contact property of a liquid and the cohesive property of a solid. However the preparation of the polymer network requires solubilization of monomers with solvents, long reaction times (6-12 h), use of catalysts, separation and purification steps: this is antithetical to the environmentally friendly nature of DSSCs and with the timing of a possible technological implementation. In this work, we highlight the great potential of free-radical photo-polymerization as a method of preparation of quasi-solid polymer electrolytes. This process is very rapid, cheap, consistent with the main canons of green-chemistry (solvents and catalysts are not required), and could be easily transferred to industrial scale. Polyethylene glycol diacrylate (PEGDA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA) were reacted under UV light in an appropriate ratio in order to obtain crosslinked, flexible and transparent membranes, subsequently activated with a I-/I3-/CH3CN solution. The entire process of preparation of these quasi-solid electrolytes lasted only 7 minutes, and a light-to-electricity conversion efficiency of 4.41% was obtained. An accurate characterization of the UV-cured membranes and the photo-electrochemical device was performed and will be here thoroughly discussed
In order to construct an efficient visible-light-driven TiO2 photocatalyst for water splitting applications, one has to perform improvements of its electronic structure. In this theoretical study we consider single-walled anatase TiO2 nanotubes having following morphologies: (101) 3-layered wall with chirality indexes (n, 0) and (n, n), (101) 6-layered wall with (n, 0) and (0, n), (001) 6-layered wall with (n, 0) and (0, n), and (001) 9-layered wall with (n, 0) and (0, n). The latter configuration occurs to be the most energetically stable, due to possessing negative strain energy. In our study the most stable 9-layered anatase (001) (0, n) nanotube has been doped with sulphur. According to obtained results sulphur dopant creates the mid-gap states making the TiO2 nanotube to be a good candidate for efficient photocatalyst working under day light irradiation.
