Electro-optical/infrared (EO/IR) sensors and photovoltaic power sources are being developed for a variety of defense and commercial applications. One of the critical technologies that will enhance both EO/IR sensor and photovoltaic module performance is the development of high quality nanostructure-based antireflectioncoatings. In this paper, we review our work on advanced antireflection structures that have been designed by using a genetic algorithm and fabri- cated by using oblique angle deposition. The antireflectioncoatings are designed for the wavelength range of 250 nm to 2500 nm and an incidence angle between 0˚ and 40˚. These nanostructured antireflectioncoatings are shown to enhance the optical transmission through transparent windows over a wide band of interest and minimize broadband reflection losses to less than one percent, a substantial improvement over conventional thin-film antireflection coating technologies. Keywords: Antireflection Coating; Nanostructured Layer; Oblique Angle Deposition; Silicon Dioxide; Broadband;
It should be noted that the discussion above exclusively considers OLEDs fabricated on stan- dard glass substrates (i.e., substrates with a refractive index around n ¼ 1.51). Thus, between the organic materials (including the indium tin oxide (ITO) electrode) and the glass substrate, there is another step in the refractive index that confines many modes to within the organic layers. Switching to index matched substrates alleviates this effect, and external outcoupling schemes can then access the combined substrate/organics modes. 39 Under these conditions, a 2.4-fold improvement in outcoupling efficiency is possible. An even higher outcoupling efficiency (3.4-fold, when using a hemisphere) can be realized if one further suppresses coupling to metal surface plasmons, e.g., by designing devices to operate in the second optical maximum and using a thick spacer layer between the emission layer and cathode. 39 The drawback of refrac- tive index matched substrates is clearly cost, and there is currently no direct pathway to bringing down the prize of high refractive index substrates to a degree that would facilitate upscaling to high-volume production. The use of a double-layer substrate has recently been demonstrated by a team at Panasonic to be a viable alternative to index matched glass substrates. 50 In this approach, a high-index polymer film [e.g., polyethylene naphthalate (PEN), n ¼ 1.77) compris- ing a microlens array (MLA) is laminated with a conventional glass substrate so that the lenses face the glass substrate and local air gaps are formed (Fig. 2). By depositing a proprietary white OLED stack (phosphorescent, tandem architecture) on top of this structure and applying thin- film antireflectioncoatings to both sides of the glass substrate, a luminous efficacy of 133 lm ∕ W and an external quantum efficiency (EQE) of 56% per tandem unit have recently been achieved. 51
In this study, we have presented the optical matrix approach method to design and simulate antireflectioncoatings on glass substrate for laser Nd-YAG wavelengths (355, 532, 1064 nm) aid matlab program at central wavelength 550 nm for double and three layer, the results show the best coating with three layer, it has one zero reflection at 355 nm and two minima at 532, 1064 nm.
9 Low spectral reflectance in the solar wavelength area indicates high absorptance and vice versa. The increases of absorptance values for the three coatings with silica AR layers are ca 1.0-1.5% while the AR layer synthesized with dip-speed of 10 mm/min exhibits the highest absorptance among all the samples. The increase of absorptance after the addition of silica is attributed to the enhanced solar absorption by the silica network which reduces the reflective properties of copper cobalt oxide coating surface where the variation of reflective properties here are related to interference phenomena governed by film thickness and refractive index ratios. Further increases of withdrawal rates, however, seem to have marginal effect on the absorptance values which suggests that the AR layer thickness does not significantly influence absorptance (as opposed to reflectance spectra profile, especially in the NIR area (>0.8 µm)). This may be elucidated based on the characteristic of the Duffie and Beckman method  in counting the absorptance value where the denser count occurred in the UV-Vis wavelengths area compared to the NIR area due to the denser spectral distribution of solar irradiance in the UV-Vis area [32, 33], therefore the reflectance spectra curve profile below 0.8 µm becomes crucial to note.
ALD deposition was recently combined with polyelectrolyte multilayer PEM) films to produce MVTR barriers. 78 A variety of PEM functional thin films can be produced using the layer-by-layer (LbL) assembly technique. 79, 80 LbL- based thin films are currently being evaluated for properties that include antimicrobial 81-83 , anti-reflection 84 , electrical conductivity 85 ,anti-flammable 86-88 , gas barrier 89-91 , and UV resistance 92 . These films, typically < 1µm thick, are created by alternately exposing a substrate to positively- and negatively-charged molecules, polymer electrolytes, or particles in a series of steps to produce the desired number of “bilayers” (or cationic-anionic pairs of layers). While excellent gas barriers have been achieved via LbL, its moisture sensitivity affects the barrier performance at higher temperatures and humidity. Hirvikorpi et al. merged the attributes of both ALD and LbL deposition techniques in attempt to reduce the MVTR of a PLA film coated with a 20nm PEM film comprising anionic sodium alginate and cationic chitosan. 78 The objective was to enable the use of moisture-sensitive-PEMs layers comprising inherent antimicrobial and fungicidal properties of chitosan with a moisture vapor barrier layer via ALD. They measured the MVTR of commercial grade PLA film (25 microns) to be 2.2 g/m 2 ∙hr at 23 o C and 75% relative humidity. Upon depositing the sodium alginate- chitosan 20 nm PEM, the MVTR increased almost 100%. Depositing a 25nm Al 2 O 3 layer on top of the PEM layer reduced the MVTR to
(sample C), respectively. First of all, sample A was fabri- cated by n-type thermal doping on p-type SiMW arrays as demonstrated in Figure 1, and 45-nm-thick AZO thin films were conformally deposited on sample A in order to make sample B. Then, to study the properties of the ZnO nanorods as an AR layer, ZnO nanorods were incorporated on the prepared sample B using hydrothermal growth. We grew vertically aligned ZnO nanorods entirely on SiMW structures and the bottom area of the Si surface. Figure 3 shows FIB SE images of sample B and sample C. As shown in Figure 3, there are observable changes between sample B and sample C. After film coating on sample A, the morphology of the resultant AZO films could not be distinguished by SEM imaging, as shown in Figure 3a. To observe the detailed morphology of the deposited films, cross-sectional FIB SE images of sample B were obtained by the gallium (Ga + ) primary ion beam sputtering and are shown in Figure 3c. It can be observed that the AZO film thickness was very similar in both side regions of the SiMWs, where the thickness of the AZO film was about 45 nm. This indicates that the highly conformal AZO films were successfully coated on sample A by ALD. In addition, the ZnO nanorod arrays were directed normally along the SiMW surface just the same as those grown on flat bare Si substrates by using the AZO seed layer (Figure 3b). It means that the AZO thin film plays the role of a metal catalyst in VLS as it serves as a buffer layer enabling the nucleation and align- ment of ZnO nanorods [20-22]. The results further con- firm that the AZO seed layer was uniformly deposited on SiMW solar cells from top to bottom areas. The FIB cross section SE image of sample C after ion beam sputtering is also given in Figure 3d.
Therefore, a multilayer coating has been adopted to further improve the coating performance including chem- ical, mechanical and tribological properties  . Each layer can provide a specific property, which has sig- nificant impact on tailoring the final coating performance. Moreover, it is found that combing coating layers with different mechanical properties can change the stress concentration in the surface area . Sidorenko et al. demonstrated that a polymer trilayer film consisting of compliant rubber interlayer can be used as an abrasion resistant nanoscale coating with low friction coefficient for silicon surface . This coating is prepared by a multiple grafting technique applied to self-assembled monolayers (SAM) and functionalized tri-block copolymer, followed by the photopolymerization of a topmost polymer layer. The compliant rubber interlayer can mediate localized stresses transferred through the top layer. Similarly, Vainshtein et al. emphasized an influence of soft base layer on scratch and abrasion resistance for oxide coating . Polydimethylsiloxane (PDMS) is applied as soft intermediate layer between polycarbonate (PC) and titania. The presence of PDMS soft layer resulted in enhanced abrasion resistance and reduction in friction coefficient due to cushioning effect, which reduces the local stress. These studies indicate that soft base layer greatly influences abrasion resistance in nanoscale. How- ever, the effect of soft base layer on macro-abrasion resistance and mar behavior for polymeric coating on po- lymer substrate has not been clarified yet.
The thermoelastic behaviors of such as temperature distribution, displacements, and stresses in thermal barrier coatings (TBC) are seriously influenced by top coat thickness and edge conditions. The top coat of TBC specimens prepared with TriplexPro™-200 system was controlled by changing the processing parameter and feedstock, showing the various thicknesses and microstructures. A couple of governing partial differential equations were derived based on the thermoelastic theory. Since the governing equations were too involved to solve analytically, a finite volume method was developed to obtain approximations. The thermoelastic behaviors of TBC specimens with the var- ious thicknesses and microstructures were estimated through mathematical approaches with dif- ferent edge conditions. The results demonstrated that the microstructure and thickness of the top coat, and the edge condition in theoretical analysis were crucial factors to be considered in con- trolling the thermoelastic characteristics of plasma-sprayed TBCs.
introduced. Moreover, S/N ratio, as contact angle, evidenced an alternating regular behaviour, characterised by values as a function of the layer number. These results suggest changes in the surface chemistry due to the LbL assembly, clearly indicated that the PSS and PAH layers were stratified. In particular, the S/N ratio (Figure 3) was lower when the PAH was the top layer, in fact nitrogen was the characteristic element of PAH, while sulphur was the characteristic element of PSS. Furthermore, PAH top layer had a contact angle value higher than PSS top layer, in fact the contact angle fluctuated between 70° and 80° (Figure 4). The same trend was found in different paper in literature, in which contact angles of LbL films generally vary between the values of the pure components of each layer [24, 35].
ABSTRACT: Concrete is the most widely used structural material in the world due to its inherent properties. The need to upgrade the deteriorated civil engineering infrastructure greatly enhances with the ever increasing demands. Ferro- cement is ideally suited as an alternate strengthening component for the rehabilitation of reinforced concrete structures. Strengthening of damaged RC beams using ferrocement laminates which are directly glued into the tension face of the beam is adopted in this study. Totally six beams have been casted and out of the six beams, one beam is kept as control specimen. Firstly the control beam is applied for ultimate load and calculated the deflection. Secondly all the remaining five beams are damaged by applying 80% load and calculated the deflections. Finally the five 80% damaged beams are strengthened by wrapping with the ferrocement laminates in different volume fractions in soffits and sides with epoxy resin. Then the strengthened beams are again tested by applying ultimate load and calculated the deflection. Then the deflection, cracking performance and ultimate flexural strength of ferrocement laminated beams are compared with the control specimen and the result is analyzed. This shows that the ferrocement laminated beam 1,2,3,4&5 has an improvement of about 30% ,50% ,40% ,47% &45% of deflection against the control beam. The ferrocement laminate increases the ultimate load by about 50%. From this experiment found that the retrofitted beam carries more load carrying capacity and less deflection than the control beam due to increase in the volume fraction of the laminate.
In recent years, solar energy utilization has increased. It is an eco free and non-polluting idea that converts the everlasting solar radiation into thermal energy/electrical energy used to fulfil the increasing demand of the energy requirements . Parabolic trough power plants are an assembly of large fields of parabolic trough collectors, steam generating systems, steam turbines/ generator cycles, thermal storage systems and fossil fired back up systems . It can be seen that the efficiency of a solar cell is majorly dependent on the type of the absorber coatings being used. , an ideal selective coating is one, which satisfies the following requirements : High absorption (α) over solar
Regarding the object recognition aspect, introspectively far less contributions can be observed. This might be traced back to the reason that object recognition for the blind might be a harder task to fulfil as compared to navigation and object avoidance. In other words, mobility and object avoidance does not pay attention to the kind of potential objects but to their presence instead, whilst object recognition emphasises on the nature of the nearby objects (i.e., not only their existence). Furthermore, recognizing objects, in camera-shot images, might come at the cost of several challenges such as rotation, scale, and illumination variations, notwithstanding the necessity to carry out such task in a brief time lapse. Nevertheless, different computer-vision techniques have been tailored to tackle this issue. In , for instance, a food product recognition system in shopping spaces was proposed. It relies on detecting and recognizing the QR codes of food items by means of a portable camera. Another work considers detecting and recognizing bus line numbers for the VI . Banknote recognition has also been addressed in . Staircases, doors, and indoor signage detection/ recognition have been considered in [10–12]. In , the authors developed a prototype composed of ultrasonic sensors and a video camera, which is embedded in a smartphone for a real-time obstacle detection and classification. They first extract FAST feature points from the image and track them with a multiscale Lucas-Kanade algorithm. Then, in the classification phase, a Support Vector Machine was used to detect one of the four objects defined a priori. Consequently, it can be observed that the scarce amount of works that have been devoted to assisted object recognition for the VI so far, emphasize on detecting/recognizing single classes of objects. On this point, it is believed that extending the process into a multiobject recognition is prone to provide a richer description for the VI people.
Wolf pruning, as defined in ISO 25178-2, allows the detection of significant features on the barrier surfaces and their characterization in terms of dimension, area, volume, shape or morphology. Wolf pruning at different thresholds, produces different counts of the number of significant features. The present study is based upon the supposition that defects above a certain scale determine the water vapour transmission through the barrier coatings. To this end feature segmentation analysis  was implemented in order to separate the significant from non-significant surface topography features. Feature parameters are not specifically defined by an equation, as are field parameters but rather use a toolbox (Surfstand) of pattern recognition techniques. The characterisation consisted of five steps; (1) selection of type of texture feature, (2) segmentation, (3) determine the significant features, (4) selection of feature attributes, and (5) quantification of feature attributes statistics. Therefore, a method of area pruning was performed by trying out various segmentation criteria. The segmentation was applied by means of an “iterative” process. The protocol used for characterising the barrier films was as follows. Firstly, the surface was filtered to eliminate data noise, where the box filtering (Gaussian filtering) uses a cut-off of 2 n points; where n is the smooth level (from 1 to 5), and n was specified to
in some papers (see f. e. ) as a finite-thickness film with a certain effective refractive index different from the refractive index of the matrix medium, as in the Maxwell-Garnett effective medium theory . However, in view of the absence of the pronounced boundaries of the layer which can be treated as the boundaries of this film, the different thicknesses of this film were determined in different works. This difficulty is easily understood considering the monolayer consisting of micellar nanoobjects, which are nuclei covered by needlelike outgrowths rather than of spherical particles. In this case, it is unobvious whether the thickness of this heterogeneous film should be defined as the diameter of the nucleus or micellar needles should be included into the film. One of the variants of the definition of the thickness is the definition of the fictitious boundaries at which the wave scattered by the layer becomes plane (all of the evanescent harmonics caused by the discrete structure of the layer and by the shape of the constituent nanoparticles are damped). Since the ratio of the total volume of the nanoparticles to the total volume of the film (filling factor) obviously depends on the definition of the boundaries of the composite film, the effective refractive index is a nonlinear function of the thickness, thus strongly affecting the resulting optical properties of the system. In the framework of the presented formalism, the indicated difficulties are absent, because the parameters are not averaged. In this case, the extinction theorem is also satisfied, because the separation of the incident wave into the reflected and transmitted waves, whose amplitudes are determined by the tensor coefficients given by Equations (19) and (21), occurs exactly on the plane passing through the centers of the nanoparticles.
500 µ m in thickness and rely strongly on the integrity of the ceramic substrate.The coating is applied using a low-temperature process that does not affect the substrate; hence, a minimal risk of damage to the component is involved. This makes coatings suitable for fused cast material which is sensitive to thermal shock. The coating process, usually carried out by plasma or flame deposition,is flexible and accommo- dates complex shapes (FFiig gu urre e 1 1((b b)) (4,9)).Direct heat- ing, where an electric current is passed through the pgm layer to heat the glass, is also compatible with this technology.
Over the past some years, machine learning has become an important subject in the trending technological field. It is a subfield of computer science and artificial intelligence that focuses on the design of systems that can learn and make decisions and predictions based on data, instead of explicitly programmed instructions. Overall it enables computers to act and make data-driven decisions rather than being explicitly programmed to carry out a certain task. One of the important uses of machine learning has been the growth of its potential in predicting the stock market. There are various factors that affect the stock market such as the core of a country’s economic strength, the rise of unlikely political scenarios, the influence of investor sentiment through newspapers and media sources etc. We isolate the other factors, considering mainly the stock data present for the commodity. Oil market is predominantly made responsible for market volatility but other commodities e.g. corn, gold and cotton have, more often than not, their influence on daily stock prices. It is seen that gold indirectly follows the movements of the market while oil does it directly. It is historical fact that gold has been viewed as a ‘counter cyclic asset’, which means it gains value during market downturns. Investors flock to the precious metal as and when outlook of the equity market
physical vapor deposition (PVD) techniques have been wildly used for synthesizing such coatings because no toxic chemical precursors are used and no toxic reaction gas or liquid bi-products are produced during the deposition process, which makes PVD to be introduced as an environ- mental friendly deposition process compared with the ther- mal chemical vapor deposition (CVD) or even plasma enhanced chemical vapor deposition (PECVD) process [6, 7]. However, due to the line-of-sight transfer of vapor flux during the PVD process, the PVD coatings usually suffer from many intrinsic defects, including columnar structures, pinholes, pores, cracks, and discontinuities, which can sig- nificantly affect their corrosion resistance, especially when the substrates are active alloys, such as steel, or exposed to a chloride ion environment . In recent years, to obtain dense microstructure of the coatings and overcome intrin- sic defects to improve the corrosion resistance of the coat- ings, several approaches have been introduced. One such strategy is using more advanced deposition technologies, for example, high power impulse magnetron sputtering (HiPIMS), which exhibits several merits over conventional PVD sputtering, such as increased film density and good adhesion, as well as some advantages over vacuum arc deposition, e.g., free from macroparticles and smooth surface . Another good approach is to add other ele- ments (Si or B) into hard coatings to form nanocomposite
When we use a cell with a p-type substrate, the p-n junction was also placed in the front side, and the solar cell was the front junction solar cell. Here, the front side will be the n-type, and the back side will be the p-type, as shown in Fig. 2. In addition, in the size of the fabricated solar cells was 1 cm2 and the p-n junction was placed under the porous layer.To determine the surface morphology of the (PSi) layerswe usedscanning electron microscopy (SEM) type (Tescan VEGA 3 SB) made in USA with Atomic Force Microscope type (Angstrom Advanced Inc. AA3000) made in Boston (USA) and The structural properties of the porous silicon layer were characterized by XRD techniques. This measurement was carried out using a high resolution X-ray device (XRD 6000 shimadzu) supplied from (Japan). PL studies were performed for all (PSi) layers using UV/Visible Spectrophotometer (The Metertech SP-8001 UV/Visible Spectrophotometer), moreover the reflection properties of nano (Psi) were measured by using TF Prop Spectroscopic reflectometer (SR) series produced by Angrstrom solar technologies (USA).
The most prevalent methods of forming Ti coatings are plasma spraying and condensation of materials from the plasma of vacuum-arc and magnetron discharges [11,12]. Titanium layer allows carrying out the MAO process in electrolyte containing calcium and phosphorus compounds. The main feature of the MAO process is the mixing of oxidizing material with ions of calcium and phosphorus coming from the electrolyte. As a result, the formation of CaP composite on the basic material occurs. A method that implies the formation of the valve group material coating of certain thickness and then its micro- arc oxidation was proposed in Tomsk Polytechnic Uni- versity (TPU) and was patented in Russian Federation . In order to reach high adhesion of the titanium layer with the basis, it was proposed to sputter the titanium with vacuum techniques, e.g. vacuum-arc evaporator.