Tile Substrates Research Articles

Structural and optical variation of pseudoisocyanine aggregates nucleated on DNA substrates

Coherently coupled pseudoisocyanine (PIC) dye aggregates have demonstrated the ability to delocalize electronic excitations and ultimately migrate excitons with much higher efficiency than similar designs where excitations are isolated to individual chromophores. Here, we report initial evidence of a new type of PIC aggregate, formed through heterogeneous nucleation on DNA oligonucleotides, displaying photophysical properties that differ significantly from previously reported aggregates. This new aggregate, which we call the super aggregate (SA) due to the need for elevated dye excess to form it, is clearly differentiated from previously reported aggregates by spectroscopic and biophysical characterization. In emission spectra, the SA exhibits peak narrowing and, in some cases, significant quantum yield variation, indicative of stronger coupling in cyanine dyes. The SA was further characterized with circular dichroism and atomic force microscopy observing unique features depending on the DNA substrate. Then by integrating an AlexaFluorTM 647 (AF) dye as an energy transfer acceptor into the system, we observed mixed energy transfer characteristics using the different DNA. For example, SA formed with a rigid DNA double crossover tile (DX-tile) substrate resulted in AF emission sensitization. While SA formed with more flexible non-DX-tile DNA (i.e. duplex and single strand DNA) resulted in AF emission quenching. These combined characterizations strongly imply that DNA-based PIC aggregate properties can be controlled through simple modifications to the DNA substrate’s sequence and geometry. Ultimately, we aim to inform rational design principles for future device prototyping. For example, one key conclusion of the study is that the high absorbance cross-section and efficient energy transfer observed with rigid substrates made for better photonic antennae, compared to flexible DNA substrates.

Ceramic tiles coated with Zr‐Ag co‐doped TiO2 thin film for indoor air purifying and antimicrobial applications

AbstractIn this study, Zr‐Ag co‐doped TiO2 (ZAT) photocatalyst films having varied numbers of layers (1, 2, 3, and 4) have been developed to coat on ceramic tile substrates by sol‐gel spin coating technique. The specimens were tested to determine antibacterial activity against Escherichia coli and the capability to degrade gaseous formaldehyde under visible light. X‐ray diffraction, ultraviolet and visible absorption spectroscopy, water contact angle, and scanning electron microscopy were applied to characterize the structural and morphological properties of the samples. The photocatalytic reactivity of the nanocomposite films was investigated by the decolorization of methylene blue (MB) dye under visible light irradiation. The results showed that the two‐layer ZAT photocatalyst film on ceramic tile exhibited the highest photocatalytic decolorization of MB, with 60.36% efficiency. The ZAT tile had formaldehyde degradation efficiency up to 32.74% within only 6 h under visible light irradiation, higher than that of the bare ceramic tile (4.90%). Additionally, the ZAT thin films could enhance anti‐E. coli activity and could be capable of degrading air pollution.

Effect of Solvent on Superhydrophobicity Behavior of Tiles Coated with Epoxy/PDMS/SS.

Superhydrophobic coatings are widely applied in various applications due to their water-repelling characteristics. However, producing a durable superhydrophobic coating with less harmful low surface materials and solvents remains a challenge. Therefore, the aim of this work is to study the effects of three different solvents in preparing a durable and less toxic superhydrophobic coating containing polydimethylsiloxane (PDMS), silica solution (SS), and epoxy resin (DGEBA). A simple sol-gel method was used to prepare a superhydrophobic coating, and a spray-coating technique was employed to apply the superhydrophobic coating on tile substrates. The coated tile substrates were characterized for water contact angle (WCA) and tilting angle (TA) measurements, Field-Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). Among 3 types of solvent (acetone, hexane, and isopropanol), a tile sample coated with isopropanol-added solution acquires the highest water contact angle of 152 ± 2° with a tilting angle of 7 ± 2° and a surface roughness of 21.80 nm after UV curing for 24 h. The peel off test showed very good adherence of the isopropanol-added solution coating on tiles. A mechanism for reactions that occur in the best optimized solvent is proposed.

Preparation and antibacterial activity of Ag/TiO2-functionalized ceramic tiles

An Ag/TiO2 coating was deposited onto glazed ceramic tiles by a sol-gel and spraying method at high temperatures. The coating was characterized by X-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results showed that silver was present in rutile-TiO2, and the temperature did not change the phase composition of the samples. The Ag/TiO2 coating had a higher roughness than the TiO2 coating. The tape test (D 3359–08) showed that the coatings prepared at 950 °C and 1000 °C had good adhesion to the ceramic tile substrate. The antibacterial activity of the coating was tested by photocatalytic sterilization experiments. The results showed that the Ag/TiO2 coating had a higher antibacterial activity than the TiO2 coating, and the sterilization efficiency of Escherichia coli, Staphylococcus aureus, Shigella, and Salmonella exceeded 99.655% under 2 h of visible light irradiation. This research provides a method to create Ag/TiO2 coatings with good thermal resistance, adhesion, and antibacterial activity. This improves the low photocatalytic activity caused by the anatase-to-rutile transformation of TiO2 at high temperatures and the poor adhesion at low temperatures.

Phase separation and spreading dynamics of French vinaigrette

Phase separation can be observed when vinaigrette is poured on a kitchen plate under certain conditions. The phase separation in vinaigrette, which comprises olive oil, vinegar, and mustard for stabilization and taste, is characterized by the outward spreading of olive oil from the main film. This phase separation and the phenomena that trigger it were investigated in this study. Moreover, the spreading dynamics of the vinaigrette were examined by analyzing the spreading factor and its rate. The spreading of different formulations of the vinaigrette was probed in this regard by varying the mass concentration of vinegar from 10% to 40% and the amount of mustard from 0.1 to 0.5 g. The emulsion films were placed on a white tile substrate with similar characteristics to those of a kitchen plate at 21 °C and a relative humidity of 50%. The spreading dynamics followed two distinct regimes; increasing the vinegar concentration of mustard-free formulations led to decreases in the spreading factor of the first regime and the spreading rate. The addition of mustard had a similar effect on the spreading factor of the first regime. The variations in these two parameters were related to changes in the system viscosity. The latter was found to be a function of the mustard and vinegar concentrations. Phase separation occurred at vinegar concentrations below 30% because of a competition between the spreading and the existing instabilities in the vinaigrette. This phenomenon did not affect spreading dynamics.

A novel protocol for producing low-abundance targets to characterize the sensitivity limits of ignitable liquid detection canines

Ignitable liquid detection canines have an extraordinarily sensitive sense of smell. Previous studies estimating canine sensitivity to ignitable liquids have been unable to demonstrate a level below which canines will not indicate ignitable presence. Forensic laboratories provide corroborating evidence and explain reasons for canine indications. Laboratories provide protection against false-positives and greater context for the exhibit contents to both investigators and the courts. However, the methods routinely used in forensic laboratories lack the sensitivity required to match canine sensitivity estimates, leading to frustration when canines provide a strong indication, but the laboratory findings are negative. In order to develop a laboratory method that can match the sensitivity of canines to trace ignitable liquids, an estimation of canine sensitivity is required. We present a protocol for producing extremely clean, porous tile substrates, and a scheme for quantitatively producing target samples with any desired abundance by using a solvent that does not elicit a response from the canines. Search experiments with two canine-handler teams validate the methods and provide the first estimate of the ignitable liquid detection canine sensitivity limit for gasoline: both canines repeatedly located gasoline at 5 pL but provided no indication at any level ≤3 pL. The protocol allows standardization of substrates and targets for canine olfactory testing, while the estimated canine sensitivity to gasoline provides a preliminary target for forensic laboratories performing confirmatory analysis on exhibits selected by ignitable liquid detection canines.

Four-Point Probe Electrical Measurements on Templated Gold Nanowires Formed on Single DNA Origami Tiles.

Bottom-up nanofabrication is increasingly making use of self-assembled DNA to fabricate nanowires and potential integrated circuits, although yields of such electronic nanostructures are inadequate, as is the ability to reliably make electrical measurements on them. In this paper, we report improved yields and unprecedented conductivity measurements for Au nanowires created on DNA origami tile substrates. We created several different self-assembled Au nanowire arrangements on DNA origami tiles that are approximately 70 nm × 90 nm, through anisotropic growth of Au nanorods attached to specific sites. Modifications to the tile design increased yields of the final desired nanostructures as much as 6-fold. In addition, we measured the conductivity of Au nanowires created on these DNA tiles (∼130 nm long, 10 nm diameter, and 40 nm spacing between measurement points) with a four-point measurement technique that utilized electron beam induced metal deposition to form probe electrodes. These nanowires formed on single DNA origami tiles were electrically conductive, having resistivities as low as 4.24 × 10-5 Ω m. This work demonstrates the creation and measurement of inorganic nanowires on single DNA origami tiles as a promising path toward future bottom-up fabrication of nanoelectronics.

FORMATION OF ANTIBACTERIAL EFFECT ON CERAMIC TILE SURFACES

Biocidal antimicrobial molecular barrier (BAMB) solutions are known to provide antimicrobial effect on the surfaces in industrial applications. However, there has been a lack of scientific reports about the subject in the literature. In this study, in order to impart an antimicrobial surface property on ceramic surfaces, a BAMB solution was applied on gloss fired ceramic wall tile substrates and the surface antimicrobial activity results were compared with that of plain wall tiles (without BAMB application). The ceramic surfaces were cleaned, and stove dried at120°C prior to spray coating with a BAMB solution. The coated substrates were dried in the ambient. The intactness of the coatings was checked with the bromophenol blue test. The microstructural and molecular characterization of the BAMB coated surfaces were carried out with SEM imaging and surface FTIR, respectively. The antimicrobial activity tests of the surfaces were conducted according to ASTM E2180-07 (Standard Test Method for Determining the Activity of Incorporated Antimicrobial Agent in Polymeric or Hydrophobic Materials). The microorganisms used were Staphylococcus aureus (ATCC 6538) and Pseudomonas aeruginosa (ATCC 15442) bacteria. The BAMB coated surfaces showed less flocculent bacterial growth in comparison to uncoated ceramic surfaces leading to the conclusion that the BAMB improved the antimicrobial property.

Camera traps and pitfalls: an evaluation of two methods for surveying reptiles in a semiarid ecosystem

Context Passive infrared cameras have become a widely utilised method for surveying mammals, providing substantial benefits over conventional trapping methods. Cameras have only recently been tested for their ability to survey terrestrial reptiles, and have not yet been tested against other reptile survey methods for their comparative effectiveness. Aims To investigate the reliability of passive infrared cameras as a reptile survey method, compared with pitfall trapping. In addition, to test a refinement of a current protocol for using cameras to survey reptiles. Methods The study was carried out in the herpetologically diverse, semiarid Mallee region of Victoria, Australia. Paired camera and pitfall lines were set up at 10 sites within Murray Sunset National Park and results from the two methods were compared. A comparison of results from cameras with and without the use of a cork tile substrate was also made. Key results Cameras were just as effective as pitfall traps for detecting some common diurnal species – detecting additional species that pitfalls did not – but were significantly less effective overall. Cameras provided lower estimates of species richness and failed to detect nocturnal species. We also discovered that cork tiles, required in other environments for the cameras to be effective in detecting diurnal reptiles, were not needed here. Conclusions Cameras can be an effective, efficient non-invasive alternative to conventional trapping methods, such as pitfall trapping, for surveying some terrestrial diurnal reptile species. However, further investigation into using cameras for surveying nocturnal reptile species is still required. Implications If the methodological issues identified during this study can be overcome, passive infrared cameras have the potential to be a valuable tool for future herpetological research.

Mechanical and tribological behavior of red clay ceramic tiles coated with fly ash powders by thermal spraying technique.

The mechanical and tribological performance of red clay ceramic tiles uncoated and coated by oxy-fuel thermal spraying process from fly ash powders was evaluated. The ceramic tile substrates were manufactured by uniaxial pressing at 26.17 bar pressure, and sintered at 1100 °C. The coating thickness was determined based on the number of projection-cycles oxyacetylene flame over substrate. Coal fly ash coatings were deposited, with average thickness of 56.18±12.18 μm, 180.42±20.32 μm, and 258.26±25.88μm. The mechanical resistance to bending and wear by abrasion deep, were studied using ISO 10545-4 standards and ISO 10545-6 respectively; adhesion was measured using Elcometer equipment Type III according to ASTM D-4541-02 and the average roughness (Ra) was found according to ASTM standard D7127-13, using the profilometer Mitutoyo SJ 201. The surface morphology presented the heterogeneous molten or semi molten splats with average size of 35.262±3.48 micrometers with good adhesion, justifying increased mechanical resistance to bending by 5%, as well as wear by abrasion deep. These results contribute to the development of ceramic products with added value, to be used in various technological applications.

From simulations to measurements: prototyping an antenna for non‐linear applications at sub‐THz frequencies

The simulated characterisation and tuning of prototype antennas prior to manufacture is described in this study. The antennas incorporate Schottky diodes so as to frequency triple incident sub-THz power. Such a dual frequency, non-linear, device has been called a multenna. A metrology is outlined for ease of multiple measurements to permit exploring scenarios of multenna element design. Four options are optimally oriented and assembled onto an appropriately dimensioned tile substrate to minimise mutual coupling during characterisation of each element individually. Transmission measurements of the multennas are performed at 100 and 300 GHz: an example of resonant behaviour is presented.

Steady-state and transient thermal measurements of green roof substrates

There has been growing interest in using extensive green roofs for commercial and residential buildings in urban areas. Green roofs provide many benefits, including adding an additional insulation layer. The potential of this benefit depends on many factors, including the thermal properties of the green roof substrate. Thermal conductivity values of three substrates comprised primarily of scoria, crushed roof tile and bottom-ash were measured with steady-state and transient techniques under three moisture conditions. Specific heat capacities of the green roof substrates were also measured with a transient technique. Steady-state measurements were performed with a “k-Matic” apparatus while transient measurements with KD2 Pro needles. In general, the steady-state measurements showed more consistency than transient measurements. Thermal conductivity differed among the three substrates: crushed roof tile had the highest conductivity values across all moisture contents. Substrate moisture content consistently increased thermal conductivity across all substrates, but this was significantly greater for the crushed roof tile substrate. Steady-state thermal conductivity curves were fitted using the thermal conductivity model for green roof substrates adopted by Sailor (2011). The coefficients obtained are presented and can be used in green roof models to quantify the thermal performance of green roofs and building energy savings.

Cold-Sprayed TiO2 Coatings from Nanostructured Ceramic Agglomerated Powders

In this work, synthesis of agglomerated TiO2, which is ready to be used after synthesis via a simple hydrolysis process, is described. The as-synthesized TiO2 powders were characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscope (TEM) and DTA. DTA curve indicated that addition of (NH4)2SO4 into the starting precursor has accelerated the hydrolysis of titanyl sulfate. The XRD patterns showed that single-phase anatase TiO2 was produced using low-temperature hydrolysis at 80°C. SEM confirmed that the as-synthesized powders were in agglomerated form and in micro size. Addition of a structure-directing agent (SDA), (NH4)2SO4, promotes agglomeration, with a denser closed packing of particle arrangement, which reduces the number of existing porosities in the synthesized powder. The TEM image showed that the primary particles were nanoparticles. The preliminary study of coating formation depicted that the powder obtained could be used as the feedstock powder for the cold spray (CS) process to make the coating as it can be deposited onto the ceramic tile substrate.

Desempeño mecánico y tribológico de baldosas cerámicas de arcilla roja recubiertas por proyección térmica a partir de alúmina

Se presentan los resultados de la evaluación de la resistencia a la flexión y al desgaste por abrasión profunda de baldosas cerámicas de arcilla roja con y sin recubrimientos de Al2O3, depositados mediante proyección térmica oxiacetilénica. Las baldosas cerámicas fueron elaboradas por prensado uniaxial a 30 bares con posterior tratamiento de sinterización a 1100°C, a partir polvos atomizados de arcilla roja. Por su parte, para la elaboración de los recubrimientos se utilizaron polvos de α-Al2O3 de referencia comercial Sulzer Metco® 105SFP, los cuales fueron depositados obteniendo tres espesores diferentes. La resistencia a la flexión y a la abrasión profunda se evaluó de acuerdo con las normas ISO 10545-4 e ISO 10545-6 respectivamente. Los resultados obtenidos indican que la abrasión profunda de las baldosas cerámicas disminuyó al incrementarse el espesor de la capa de alúmina depositada. Por otra parte, los recubrimientos de alúmina incrementaron entre un 5 y un 49% la resistencia mecánica a la flexión de las baldosas de arcilla de acuerdo con el espesor y la adherencia de la capa al sustrato. Los resultados obtenidos contribuirán al desarrollo de productos cerámicos con valor agregado, para ser usados en diversas aplicaciones tecnológicas.

Tailoring of the electrical properties of carbon black–silica coatings for de-icing applications

Electrical heating properties of carbon black–silica composite coatings have been studied for de-icing devices. Coatings are consolidated by spray deposition onto tile substrates and thermal treated in the temperature range of 300–500°C in air atmosphere. The electrical properties of the coatings depend on the thermal treatment as for higher sintering temperatures the coatings are more resistive, and consequently the heating produced by the Joule effect is more significant. Therefore, it is possible to tailor the heating properties of the coatings by means the thermal treatment, achieving thin coatings with low electrical resistance (~5×10−4Ωm), or coatings with higher resistivity (~5×10−3Ωm) which produce thermal heating >70°C with heating rate >0.13°Cs−1. This coating heating is determined using DC intensity–voltage curves and thermal infrared camera. The relationship between electrical power and temperature increasing showed a nearly linear dependence. The experimental results for these coatings allow their use in a wide range of functional applications, such as de-icing devices for aeronautics.

Colonisation and community structure of benthic diatoms on artificial substrates following a major flood event: A case of the Kowie River (Eastern Cape, South Africa)

A major flooding event that occurred during October–November 2012 caused major changes in the Kowie River hydromorphology and aquatic communities. The aim of our study was to identify the environmental variables that structure riverine benthic diatom communities at upstream and downstream locations 25 km apart on the Kowie River, South Africa. This was undertaken using tiles as artificial substrates so that we could study how the communities developed after the flood disturbance. The diatom community structure was assessed over a 28-day period following a flood event in October 2012. The Mann Whitney test indicated that there was a statistically significant difference (p < 0.05) in total dissolved solids, salinity, pH and oxygen reduction potential between the two sites. In total, 58 diatom species belonging to 30 genera were identified over the 28-day study. Achnanthidium minutissimum, Fragilaria biceps, F. ulna var. acus, Pinnularia borealis and P. acrosphaeria were the most numerically dominant on Day 7 and were considered as early colonisers, while on Day 28, Achnathidium minutissimum, F. capucina, Craticula buderi, C. vixnegligenda, Diploneis subovalis and Gomphonema venusta, the late colonisers, were dominant. The species richness increased from 13 (upstream location) on Day 7 to 22 (both locations) by Day 21. A redundancy analysis showed that total suspended solids, salinity, resistivity, pH and oxygen reduction potential were the most significant physico-chemical variables explaining diatom composition. The results from this relatively small-scale tile experiment indicate the complexity of freshwater benthic diatom community structure and development.Keywords: water flow, total dissolved solids, Fragilaria sp., tile substrate, resistivity

Use of inorganic substrates and composted green waste in growing media for green roofs

Inorganic substrates are used as the primary component in green roof growing media because they can provide the desired physical properties and are thought to be physically, chemically and structurally stable over time. Inorganic substrates can be amended with organic matter to help establish vegetation on green roofs but there is little information on how this affects the physical properties; dry bulk density, water holding capacity and air filled porosity; of the resulting growing medium or whether the effects are the same for all inorganic substrates. Nine crushed brick and three crushed tile substrates obtained from five UK suppliers of aggregates were amended with 30% v/v composted green waste. The physical properties of the substrates and growing media mixes were determined using the gravitational drainage technique. Amending the inorganic substrates with composted green waste significantly improved the physical properties by reducing the dry bulk density and increasing the water holding capacity. Air filled porosity of inorganic substrates decreased with addition of fine composted green waste but aeration was always adequate for plant growth and survival. This provides evidence of the beneficial effects of inclusion of composted green waste on the physical properties of inorganic substrates for green roof growing media but highlights the fact that the responses to inclusion of composted green waste may be different for different inorganic substrates or grades of substrate.

Conductive coatings with low carbon-black content by adding carbon nanofibers

Abstract Conductive coatings based on low carbon-black content by adding carbon nanofibers are obtained in a silica matrix obtained by the sol–gel process. The carbon nanofibers incorporation allows reducing the percolation threshold down to 20 wt.% of carbon black into the silica matrix obtaining good electrical properties. Coatings are deposited by air-spray deposition onto tile substrates and sintered in the temperature range of 300–500 °C in air atmosphere. The coatings achieve resistivities as low as 2 × 10 −3 Ωm due to the percolation between the carbon black nanoparticles and carbon nanofibers which improves the conductive paths. The samples are microstructural characterized by Scanning Electron Microscopy and Confocal Raman Spectroscopy. The electrical properties are measured by impedance spectroscopy. The thermal properties derived of the Joule effect are measured using DC intensity–voltage curves and thermal infrared camera, and it is observed a nearly linear relationship between electric power and temperature increasing in the measured range. Thereby, a wide range of application is opened by means of tailoring the electrical response of the coatings: higher resistivity coatings produce thermal heating above 90 °C, appropriated for electric heaters, and conductive coatings are suitable for electronic devices, electrodes and EMI/RFI shielding.

Incorporating herbivorous sea urchins in ramet culture of staghorn coral Acropora cervicornis

Since the 2006 listing of the staghorn coral Acropora cervicornis as threatened under the US Endangered Species Act, interest has increased in its culture for laboratory studies, resto- ration and ex situ conservation efforts. A pervasive problem in coral culture is substrate over- growth by algae and other spatial competitors. We conducted a laboratory study to examine the utility of introducing herbivores, juvenile variegated sea urchins Lytechinus variegatus, to tanks containing small (<1 cm 2 ) A. cervicornis ramets. Growth of coral ramets on ceramic tile substrates was monitored in recirculating seawater tanks over 210 d and measured in terms of area change under 3 treatment conditions: (1) presence of laboratory-reared, juvenile, variegated sea urchins; (2) weekly scraping of algal turfs from the tile substrate by means of a razor blade; and (3) absence of both urchins and manual turf removal (i.e. control). Over the course of the study, coral area decreased in the control treatment, but increased in the scraped and urchin-containing treat- ments. All 3 treatments differed significantly from one another, with the highest growth rate (3.1 mm 2 d �1 ) associated with the manual removal of algal competitors, followed by the urchin (1.9 mm 2 d �1 ) and control treatments (�0.8 mm 2 d �1 ). Given the relative ease of L. variegatus cul- ture, the incorporation of variegated sea urchins in the coral ramet production process appears to provide at least a partial substitute for manual algal removal. Although coral growth in the pres- ence of urchins was slower than with manual removal, human labor costs associated with the lat- ter may out-weigh any production rate improvements in large-scale operations.

Preparation of nitrogen co-doped SiO2/TiO2 thin films on ceramic with enhanced photocatalytic activity under visible-light irradiation

In this study, we have successfully deposited N-doped SiO2/TiO2 thin films on ceramic tile substrates by sol–gel method for auto cleaning purpose. After dip coating and annealing process the film was transparent, smooth and had a strong adhesion on the ceramic tile surface. The synthesised catalysts were then characterised by using several analytical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscope (AFM) and UV-vis absorption spectroscopy (UV-vis). The analytical results revealed that the optical response of the synthesised N-doped SiO2/TiO2 thin films was shifted from the ultraviolet to the visible light region. The nitrogen substituted some of the lattice oxygen atoms. The surface area of co-doped catalyst increased, and its photocatalytic efficiency was enhanced. The photocatalytic tests indicated that nitrogen co-doped SiO2/TiO2 thin films demonstrated higher than of the SiO2/TiO2 activity in decolouring of methylene blue under visible light. The enhanced photocatalytic activity was attributed to an increasing of the surface area and a forming of more hydroxyl groups in the doped catalyst.