Xenon Arc Research Articles

Ultramarine blue containing paint layers: Further study of the photo-catalytic degradation of binding media

Photo-catalytic degradation of a linseed oil binder by natural ultramarine (Lapis Lazuli or Lazurite) and Sodalite in paint layers was studied. Both pigments degrade the binder under xenon arc exposure, leading to erosion of the binder at the surface, increased roughness, light scattering and desaturation of the color. Both pigments behave similarly to synthetic ultramarine blue studied earlier. The results for Sodalite provide further proof that the zeolitic nature of the aluminosilicate cage causes the catalytic degradation and that the enclathrated polysulfur radical anions S2-. and S3-. trapped inside the cage are not responsible for the catalytic action. Relatively stable synthetic binders are less affected by the presence of synthetic ultramarine blue. The paints were aged in a xenon arc apparatus using a simulated indoor environment (radiation > ca. 320 nm). The samples were analyzed using diffuse reflectance spectroscopy in the UV–vis and short wavelength infrared (SWIR) ranges, Raman spectroscopy, field-emission gun scanning electron microscopy (FEG-SEM) and FTIR.

Investigation of Photoinduced Deterioration in Shadow Puppet Artifacts Collected from the National Shadow Pupperty Museum in Chengdu, China

Shadow puppet artifacts are a special type of cultural heritage made from animal skin, possessing significant cultural and artistic value. However, there is insufficient attention to the scientific preservation of these artifacts, and systematic research on their protection is lacking. In particular, light as an important factor and related conservation studies are weak. This study investigates the photoinduced deterioration of shadow puppet artifacts from the National Shadow Pupperty Museum in Chengdu collection. Based on the xenon arc lamp are a common method of light aging, the modern rawhide samples were aged by the xenon arc lamp to simulate photoinduced deterioration. After artificial light aging, the samples were stored in a stable environment (with temperature maintained at 22 ± 2°C and relative humidity maintained at 50 ± 5%RH) for 150 days. It attempts to avoid further deterioration of the samples due to drastic cyclic changes in the environment. And continuously observe changes in characteristics during this process to verify the potential reversibility of photoinduced deterioration. Comprehensive assessments were conducted to gauge the extent of deterioration. In order to assess the deterioration, a series of analytical techniques were used. Moisture gain or loss was inferred from mass changes, and colorimetric measurements were measured using the CIELAB formula. Macroscopic and microscopic morphological damage was documented through camera, stereo microscope, and scanning electron microscope observations. Fourier transform infrared spectroscopy (FTIR) assessed amide bond degradation and moisture loss, while thermogravimetry/differential thermogravimetry (TG/DTG) evaluated collagen denaturation and thermal stability. The results indicated that prolonged light exposure caused significant deterioration, including color fading, moisture evaporation, and structural damage such as shrinkage and cracking. The findings indicate that light exposure is a crucial factor in the preservation of shadow puppet artifacts. Therefore, it is essential to implement careful management strategies in museum environments to ensure the protection of these artifacts.

Experimental Evaluation of Geometric and Environmental Effects on Mechanically Fastened Non-Crimp Fabric Composites.

Corresponding to marine environmental regulations is important in shipbuilding and marine industries. The application of lightweight composite materials on ships is an effective approach to reducing the emission of greenhouse gases. The mechanical fastening method is a good candidate to assemble composites and conventional metals. The joint geometric and environmental effects are two important factors in mechanically fastened ship and marine structures. In this study, we evaluated the W/D (hole diameter to width ratio) and environmental effects on the bearing strength and failure mode of a mechanically fastened non-crimp fabric (NCF) composite material. To consider the effect of joint geometry, wherein hole diameters of 5, 6, 8, and 10 mm were machined. Further, by selecting three environmental conditions (UV, saltwater and low temperature), we evaluated environmental effects on bearing strength and failure modes of NCF composite specimens. The bearing strength increased as W/D decreased, and the bearing strength of the specimen exposed to low temperature and UV environments increased, while that of the specimen exposed to saltwater remained the same. From the failure mode analysis, the specimen that was exposed to salt fog showed the same failure mode as the unaged specimen. It was observed that the changes in the transition section and new failure mode in the xenon arc and low-temperature specimens.

Light-enhancing ketone transfer hydrogenation catalyzed by diphosphine phenanthroline ruthenium complexes

The cationic phenanthroline ruthenium derivatives [Ru(OAc)(dppb)(NN)]OAc (NN = phen 1, imidazo[4,5-f][1,10]phenanthroline 2) have been obtained in high yield by reaction of the acetate [Ru(OAc)2dppb] with the corresponding NN ligand. The dinuclear cyclometalated [(dppb)(η2-OAc)(Ru(µ-NN-phenimid-NC)Ru(η2-OAc)(dppb)]OAc (3) has been prepared from 2 with [Ru(OAc)2(dppb)] via elimination of acetic acid. The characterization of these compounds has been carried out by NMR, FT-IR, UV–Vis, conductivity and cyclic voltammetry measurements. These derivatives display catalytic activity in the transfer hydrogenation of aromatic and aliphatic cyclic ketones at S/C up to 2000 in presence of NaOiPr in 2-propanol. An increase of the rate (up to 8 times) has been observed upon irradiation at 30 and 60 °C (300 W Xenon Arc Lamp light source). Control experiments show that [Ru(OiPr)2(dppb)(phen)] (1A), formed from 1 by substitution of the acetate with the isopropoxide ligand, shows a stronger emission compared to 1 and that 1A is quenched by NaOiPr, affording the dihydride [Ru(H)2(dppb)(phen)] (1C) via a photo induced β-H elimination.

Utilizing machine learning algorithms for precise discrimination of glycosuria in fluorescence spectroscopic data

Fluorescence spectroscopy coupled with a random forest machine learning algorithm offers a promising non-invasive approach for diagnosing glycosuria, a condition characterized by excess sugar in the urine of diabetic patients. This study investigated the ability of this method to differentiate between diabetic and healthy control urine samples. Fluorescent spectra were captured from urine samples using a Xenon arc lamp emitting light within the 200 to 950 nm wavelength range, with consistent fluorescence emission observed at 450 nm under an excitation wavelength of 370 nm. Healthy control samples were also analyzed within the same spectral range for comparison. To distinguish spectral differences between healthy and infected samples, the random forest (RF) and K-Nearest Neighbors (KNN) machine learning algorithms have been employed. These algorithms automatically recognize spectral patterns associated with diabetes, enabling the prediction of unknown classifications based on established samples. Principal component analysis (PCA) was utilized for dimensionality reduction before feeding the data to RF and KNN for classification. The model’s classification performance was evaluated using 10-fold cross-validation, resulting in the proposed RF-based model achieving accuracy of 96 %, specificity of 100 %, sensitivity of 93 %, and precision of 100 %. These results suggest that the proposed method holds promise for a more convenient and potentially more accurate method for diagnosing glycosuria in diabetic patients.

Design and numerical simulation of a 45 kWel multi-source high-flux solar simulator as a heating source of dielectric materials positioned in a microwave characterization cavity

This study reports the design and modelling of a high-flux solar simulator (HFSS) combined to a resonant cavity for microwave dielectric properties characterization of ceramics at very high temperatures. The HFSS comprises seven xenon arc lamps with ellipsoidal reflectors, delivering a maximal electrical power of 6.5 kWel each. Positioned on a virtual sphere of around 1600 mm radius, the lamps provide concentrated irradiation heating on a sample positioned inside the resonant cavity. The propagation of the lamp’s irradiation to the sample and the cavity is simulated using Monte Carlo ray tracing method. An ANSYS Fluent finite volume method for solving the resulting multimode heat transfer and flow indicate a radiative flux reaching 1.84 MW m−2, and a sample temperature of approximately 1470°C with 10 % non-uniformity. These results suggest that the designed heating system and resonant cavity is suitable for conducting microwave dielectric properties characterization of refracting ceramic materials at high temperatures, addressing a gap in studies focusing on temperatures exceeding 1000°C.

Integrated Circular Dichroism and Circularly Polarized Luminescence Measurements.

Circularly polarized luminescent (CPL) systems have a plethora of potential applications owing to their interesting excited-state properties. However, the progress in developing new chiral luminescence systems is significantly hindered by the lack of available instrumentation for the broader chemistry and materials science community to perform routine, reproducible measurements of chiral spectroscopies. In this work, we present data from an easy-to-use custom-built instrument based on a Jasco circular dichroism (CD) spectropolarimeter coupled with a CPL emission monochromator (CD/CPL hybrid system). The hybrid system measures CPL, fluorescence, CD, and absorbance on the same part of the sample without the need to move between the CD and CPL measurements. The instrument uses a xenon arc lamp as the light source, enabling a wide range of excitation wavelengths to support flexible development of new molecules and materials. Data obtained and presented for camphor, ruthenium metal complexes, the peptide gramicidin, and a DNA-ligand (4',6-diamidino-2-phenylindole, DAPI) system in this work highlight the ease of use and reproducibility of the results. The g-factors for CD and CPL obtained for the different compounds are shown to be the same for isolated transitions and some examples of how to use variations of g-factors with wavelength are demonstrated. The reliable and excellent benchmark results obtained from a custom-built commercial wavelength scanning CPL/CD hybrid instrument open up new avenues for the broader chemical and materials science community to intensify research on chiral luminescent systems.

Photoaging of biodegradable nanoplastics regulates their toxicity to aquatic insects (Chironomus kiinensis) by impairing gut and disrupting intestinal microbiota

Biodegradable plastic, a widely used ecofriendly alternative to conventional plastic, easily form nanoplastics (NPs) upon environmental weathering. However, the effects and underlying mechanisms governing the toxicity of photoaged biodegradable NPs to aquatic insects are not understood. In this study, we investigated the photoaging of polylactic acid nanoplastics (PLA-NPs, a typical biodegradable plastic) that were placed under xenon arc lamp for 50 days and 100 days and compared the toxicity of virgin and photoaged PLA-NPs to Chironomus kiinensis (a dominant aquatic insect). The results showed that photoaged PLA-NPs significantly decreased the body weight, body length and emergence rate of C. kiinensis. Additionally, photoaged PLA-NPs induced more severe gut oxidative stress, histological damage, and inflammatory responses than virgin PLA-NPs. Furthermore, the alpha diversity of gut microbiota was lower in photoaged PLA-NPs group than virgin PLA-NPs. The relative abundance of key gut bacteria related to intestinal barrier defense, immunity, and nutrient absorption was reduced more significantly in photoaged PLA-NPs group than virgin PLA, indirectly leading to stronger gut damage and growth reduction. A stronger impact of photoaged PLA-NPs on the gut and its microbiota occurred because photoaging reduced the size of NPs from 255.5 nm (virgin PLA) to 217.1 nm (PLA-50) and 182.5 nm (PLA-100), induced surface oxidation and enhancement of oxidative potential, and improved the stability of NPs, thereby exacerbating toxicity on the gut and its microbiota. This study provides insights into the effects of biodegradable NPs on aquatic insects and highlights the importance of considering biodegradable nanoplastic aging in risk assessments.

Environmentally friendly YIn0.9Fe0.1O3-ZnO yellow pigment displaying near infra red (NIR) reflectance and photocatalytic activity

In this research, we produced ochre/yellow pigments of YIn0.9Fe0.1O3, combined with ZnO pigments, through a citrate-assisted sol-gel approach. We investigated the impact of varying ZnO addition methods (incorporated into the sol-gel bath and physically mixed with YIn0.9Fe0.1O3 pigments) on their color properties, near-infrared (NIR) reflectance and photocatalytic activity. The effect of the different ZnO addition methods was investigated on pprecursors and final calcined pigments through X-ray diffraction (XRD), Vis-NIR reflectance, Fourier transform infrared spectroscopy (FT-IR) Scanning Electron Microscope (SEM) and thermal analyses such as thermogravimetry (TGA), and differential scanning calorimetry (DSC). The synthesized nanocomposites were evaluated for their photocatalytic characteristics by examining the degradation of 4-Nitrophenol (4-NP) when exposed to UV radiation. The potential environmental applications of the pigments were investigated not only for direct pollutant degradation but also in terms of energetic sustainability. In fact, the developed pigments can be employed as passive cooling materials to mitigate the temperature of buildings, thus dramatically reducing energy consumption. For this reason, the pigments were embedded into a polymeric binder and coated onto roofing aluminum sheets. The obtained coatings were investigated in terms of NIR reflectance and heat adsorption. The photocatalytic ability of the coatings was assessed by the degradation of 4-NP and methylene blue (MB) under xenon arc lamp. The results obtained indicate the feasibility of producing a pale yellow pigment with both NIR reflectance and photocatalytic capabilities.

Adhesion of electron-beam evaporated SiO2/TiO2 anti-reflective coating on ion-treated polycarbonate substrate under xenon arc accelerated weathering test

Anti-reflective (AR) coatings on polymer substrates enhance light transmittance and minimize reflectance loss. However, durability of multi-layered AR coatings on polymer substrates under various weathering conditions (temperature, radiation, and humidity) can be challenging and affecting adhesion of the coating to the substrate. Therefore, in the present work, Xenon arc accelerated weathering test followed ISO 16474 guidelines was used to investigate durability of electron-beam evaporated SiO2/TiO2 stacking layer as the AR coating on an ion-treated polycarbonate (PC) substrate by varying anode voltage of the ion treatment, oxygen flow rate during the treatment, and thickness of a binding layer (Chromium-based alloy) sandwiched between AR coating and PC substrate. Crosshatch tape test based on ASTM D3359 was used to evaluate the adhesion performance. Physical changes of ion-treated PC surface were characterized by atomic force microscopy and scanning electron microscopy, whereas Fourier transform infrared spectroscopy was adopted to identify chemical functional groups on the treated PC surface. Residual stress and optical reflection of AR coating on the PC were measured by laser interferometry and UV–Vis spectrophotometry, respectively. As anode voltage increased with no oxygen flow, average surface roughness of PC increased but the roughness decreased as oxygen flow rate increased when the highest anode voltage (100 V) was applied. A reversed trend of the roughness achieved with the lowest anode voltage (80 V). Amount of C–O functional group on treated PC increased when the average surface roughness decreased. The adhesion improved by incorporating a binding layer, depending on anode voltage and oxygen flow rate, that can alter residual compressive stress of the material system, reduce moisture and UV attack without sacrificing optical performance of the AR coating. Generally, a better AR coating adhesion can be achieved with smoother PC surface having higher amount of C–O bonding, and higher overall residual compressive stress.

Exploring polyamide 11 as a novel renewable resource-based filler in wood paint: Investigating aesthetic aspects and durability impact of the composite coating

The aim of this study is to assess the impact of different quantities of polyamide 11 powder on the visual appeal, durability, and multi-functionality of a water-based wood paint. To investigate the effect of this bio-based additive on the overall appearance of the coatings, measurements for color, gloss, and surface roughness were conducted. Additionally, various tests were performed to quantify the influence of these environmentally friendly additives on the mechanical properties of the coatings, including hardness, surface friction coefficient, and resistance to abrasion. Moreover, the effect of varying amounts of polyamide 11 powder on the coating's barrier capabilities was evaluated through liquid resistance tests, contact angle measurements, and water uptake assessment. Finally, the influence of the bio-based additive on the layers' durability was evaluated by subjecting them to exposure in a xenon arc light chamber. The degradation of the samples was monitored through colorimetric inspections to assess any changes or deterioration. In summary, this study underscores the significant impact of varying the quantity of polyamide 11 powder, showcasing its ability to not only introduce distinct texture to the paint but also significantly enhance the mechanical properties of the composite layer. Importantly, these improvements are achieved without compromising the barrier properties and durability of the acrylic matrix coating.

Cellulose Fabrics Functionalized with Sol-Gel Photocatalytic Coatings Based on Iron (III) Phthalocyanine Tetracarboxylic Acids-TiO2-Silica Hybrids.

Photocatalytic coatings are difficult to obtain on textile materials because of the sometimes contradictory properties that must be achieved. In order to obtain a high efficiency of a photocatalytic effect, the metal-oxide semiconductor must be found in the vicinity of the coating-air interface in order to come into direct contact with the contaminant species and allow light radiation access to its surface. Another necessary condition is related to the properties of the covering textile material as well as to the stability of the xerogel films to light and wet treatments. In this sense, we proposed a solution based on hybrid silica films generated by sol-gel processes, coatings that contain as a photocatalyst TiO2 sensitized with tetracarboxylic acid of iron (III) phthalocyanine (FeTCPc). The coatings were made by the pad-dry-cure process, using in the composition a bifunctional anchoring agent (3-glycidoxipropyltrimethoxysilane, GLYMO), a crosslinking agent (sodium tetraborate, BORAX), and a catalyst (N-methylimidazole, MIM) for the polymerization of epoxy groups. The photodegradation experiments performed on methylene blue (MB), utilized as a model contaminant, using LED or xenon arc as light sources, showed that the treatment with BORAX improves the resistance of the coatings to wet treatments but worsens their photocatalytic performances.

Accelerated weathering of sustainable and micro-filler Basalt reinforced polymer biocomposites: Physical, mechanical, thermal, wettability, and water absorption studies

This study intends to evaluate and comprehend the accelerated weathering behavior of various thermoset and thermoplastic composites loaded with an eco-friendly basalt micro-filler. Basalt incorporation into various polymer matrices is, in fact, a very innovative idea that might present some very exciting, as yet unexplored, perspectives. The four kinds of thermoset polymers (synthetic epoxy, bio-epoxy, polyester, vinyl ester) were reinforced with constant basalt reinforcement (30 wt %) and fabricated via the casting process. Whereas the three kinds of thermoplastic (polylactic acid, polypropylene, high-density polyethylene) polymers were also loaded with a constant basalt ratio and manufactured through an internal mixing process followed by a compression molding technique. The fabricated samples were employed inside the xenon arc light accelerated weathering equipment under ultraviolet (UV) rays, temperature, and humid conditions for 555.55 h as per ASTM G155-13 cycle 1. There is a significant improvement in the density of polymer composites due to highly dense basalt particle incorporation and maximum void percentage was observed in thermosets due to casting defects than in the thermoplastic samples. After weathering, the tensile, flexural, and impact properties of composites were significantly reduced due to the thermo-oxidative reaction and degradation under UV and moisture exposure. As a result of UV-induced chain scission, small fractures may develop. These spaces provide the ideal environment for moisture to infiltrate into the primary composite structures, weakening the links between the reinforcement and matrix. Scanning electron microscopy was used to analyze the significant changes in the surface morphology of weathered and unweathered tensile fractured samples. The hardness was considerably improved due to the presence of highly stiffen and hard basalt particles. The idea that accelerated weathering destruction creates hydrophobic surface characteristics in most of the composites due to a variety of factors, like physical and chemical transformations, is supported by the increased contact angle value and a decrease in surface free energy, particularly the polar section. The thermogravimetric analysis revealed that there is not much significant impact of weathering on composites, however, variations were observed in the thermomechanical analysis due to compatibility issues. It is observed that the onset and endset degradation temperatures got decreased with the reinforcement of 30 wt% basalts after the internal mixing process. This could be brought on by the molecular weight decreasing while mixing. The behavior of polymer composites in water absorption study is found to be unique depending on their hydrophilicity and defects raised during the fabrication.

A Hanbury Brown and Twiss renascence: measurement of photon correlations yields spatio-temporal coherence

Investigations of photon correlations similar to the Hanbury Brown and Twiss experiment are since the advent of quantum optics in the center of both fundamental and application-oriented research. We derive a factorial moment-generating function of the probability distribution of electromagnetic radiation emitted by a source and absorbed by a photodetector from which we calculate an analytical expression for the second-order correlation coefficient g^{(2)} which reflects spatial coherence properties of the emitted light. The measurement of g^{(2)} thus allows to retrieve the spatial coherence parameter of the light source in terms of the combination of source area, source-detector distance, wavelength and detector area. The validity of the concept is proven by investigating g^{(2)} of true thermal light from a Xenon arc lamp and from the sun for various detector areas, in excellent agreement with the theory. Finally, we suggest a novel scheme for determining light source diameters by exploiting the spatially dependent statistics and confirm its validity by exemplary calculations. These results based on radiation thermodynamics and photon statistics give fresh insight into quantum optical properties of classical light sources, photon correlations and photodetection with promising applications perspectives, more than 68 years after the original Hanbury Brown and Twiss experiment.

NiO & CuO nanocomposites coated photoanode for conversion of CO2 into solar fuel using photoelectrochemical cell

ABSTRACT Photoelectrocatalytic reduction of carbon dioxide to solar fuel exists as a novel approach for addressing energy demand, and environmental concerns due to high efficiency and less energy requirement as compared to other technology. The predominant goal of the current work is to investigate the impact of metal oxide (NiO & CuO) supported photoanodes for enhancing CO2 conversion into solar fuel using a photoelectrochemical cell (PEC). The photoanodes were incorporated with rGO with combinations of metal oxide nanocomposites and coated on the electrode surface. The PEC consists of anode and cathode compartments divided by proton exchange membrane, the anode and cathode are filled with 0.1 M KOH and 0.5 M KCl respectively. The xenon arc lamp (100W) is used as a light source and carbon dioxide is supplied with a flow rate of 10 mL/min. The synthesized nanoparticles were characterized using XRD, FTIR, and Cyclic Voltammetry. The experimental results showed that the NiO-coated photoanode observed the better performance than CuO coated electrode and it had achieved the maximum solar fuel (Formic Acid) production rate of 9.223 μmol/hr/cm2 with a Faradic efficiency of 14.83% as compared to the control electrode.

Valorization of bio-colorants extracted from Hypercium scabrum L. plant for sustainable and ecological coloration of wool yarns

Recently, natural dyes are being explored all over the world as safer and highly sustainable bio-based alternatives to synthetic dyes. Agricultural wastes and plant by-products are the most commonly explored alternatives with dual benefits of waste reclamation and sustainable dye production with extra value-adds. Hypercium scabrum plant contains interesting bio-dye molecules with high flavonoids and tannin contents. The present study aims at exploring the potential of H. scabrum plant extract to color wool textiles with a focus on sustainable bio-dye production and fastness properties. The extracted bio-dye was quantitatively (for total phenolic (2.733 mg per CE/g) and total flavonoid (1.140 mg per GAE/g) content using the Folin–Ciocalteu method) and qualitatively (UV–Vis, FT-IR, and EDX) characterized. The effect of dyeing parameters like pH (2–8), temperature (60–90 °C), dry-weight content of plant material as a dye (25–150% o.w.f.), and dyeing time (15–120 min) on color strength (K/S) values were assessed. Color fastness assays showed good resistance to light, washing, and rubbing. The effect of artificial aging (Xenon arc lamp) on the color strength of dyed wool yarns under different exposure times (0–48 h) was explored. The highest color fading occurred in control dyed samples with a first-order rate constant of 131.57 h−1 and a half-life period of 5.26 x 10−3 h. Color difference (ΔE) values suggested that mordanted samples showed less fading compared to control dyed samples at equal times of Xenon exposure. Additionally, the dyed samples were washed in double distilled water, tap water, and 4 g/L NaCl solution to check their effects on the corresponding K/S values while 4 g/L NaCl solution mimics the real conditions of perspiration. Maximum color leaching occurred in 4 g/L NaCl washing with a first-order rate constant of 11.57 min−1. Cost analysis of the dye extraction and dyeing procedure revealed that the process is sustainable and economical. Thus, the use of H. scabrum whole plant can provide a clean, economical, and sustainable source of alternative natural dyes that can be used to substitute synthetic analogs.

Digitization in Skin Shade Matching for Maxillofacial Prostheses: A Systematic Review.

Color matching of maxillofacial prostheses for the restoration of maxillofacial defects is an important factor for esthetic results. Various methods have been introduced for the accurate and reliable color matching of prostheses with the skin color of patients. A systematic review was conducted to search the existing literature on color-matching digital techniques for maxillofacial prostheses. An electronic literature search was conducted in PubMed/Medline, Scopus, and Web of Science from January 2000 to December 2022 using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Two independent reviewers conducted the search. Eight articles that fulfilled the inclusion criteria after a full-text evaluation were included in this review. Most of these studies were published in prosthodontics journals and conducted in various countries around the world. A computerized color formulation system was used in three studies; a non-contact spectroradiometer (PR 705; Photo Research Inc., Chatsworth, CA) with a Xenon arc lamp was used in two studies; a mobile phone colorimeter was used in one study; additive manufacturing of 3D facial skin with a spectrophotometer was used in one study; and a recently introduced computerized method known as e-skin(Spectromatch, Bath, UK) was used in two studies. Most of these methods were accurate in color matching, except for the additive manufacturing system, which showed less accuracy, but good repeatability. Owing to a lack of sufficient studies, no method can be labeled as the best method for color-matching maxillofacial prostheses. The latest computerized method, the e-skin, can be used to achieve better accuracy and good color matching. However, further studies are required to validate the use of e-skin for precise color matching.

Novel high-flux indoor solar simulator for high temperature thermal processes

A novel 32 kWe high flux solar simulator compound of eight xenon arc lamps coupled with a truncated paraboloid mirror and a secondary paraboloid mirror was designed, built, and tested. Collimated rays from a set of xenon arc lamps emulating outdoor solar radiation were reflected by a secondary set of paraboloid mirrors to a common system focus. Relative irradiance measurements were performed to obtain the xenon arc lamp radiation spectrum. Thermal power delivered by each lamp was evaluated by using a heat flux gauge mounted at the system focus. Concentrated thermal power was estimated by the heat superposition method, which allowed us to quantify both the total and the concentrated peak power along with the heat flux mapping. A 10.2% energy conversion efficiency was achieved. Experimental results determined a 3.0 kW total concentrated power on a 100 mm spot diameter resulting in a 1028 kWm−2 peak flux at the center; a lamp total thermal radiant power average of 615 W was achieved, and the lamp spectrum was compared with the 6200 K blackbody radiation spectrum.

Direct evaluation of the ozone production regime in smog chamber experiments

Understanding the atmospheric ozone (O3) production regime is necessary for development of strategies to effectively control the amount of atmospheric O3. We have developed an instrument to directly evaluate the O3 production regime by measuring incremental changes of O3 production rate after injection of nitric oxide and propene into sample air. In this study, we conduct smog-chamber experiments on the oxidation of nitrogen oxides (NOx) and volatile organic compounds (VOC) and use the above instrument to measure O3 production during air mass oxidation. We also perform box model simulations with two chemical mechanisms (one near-explicit and one lumped) to cross validate the measured and simulated O3 production regimes. Oxidation experiments are conducted under VOC-rich and NOx-rich conditions; and the simulation generally reproduced O3 concentrations, OH reactivity (OHR), and contribution of NOx to total OHR. The measured O3 production regime changed from VOC-limited to NOx-limited after 1–3 h of irradiation by xenon arc lamps under the VOC-rich condition, whereas the regime remains VOC-limited throughout our experiment under the NOx-rich condition. The simulated timing of the regime transition under the VOC-rich condition is slower than that of the measured data, which could be attributed to overestimation of the NOx concentration. Both the measured and simulated timing of the regime transition estimated from the sensitivity to injection of O3 precursors NOx and VOC agree well with that estimated from the radical budget. The O3 production regimes estimated by the new instrument and by simulations are consistent with each other, suggesting that both methods are useful for estimating O3 production regime.

Cu doped YInO3-ZnO green colored NIR reflective pigments: Synthesis and application in PMMA based cool-roof coatings

A series of Cu modified YInO3-ZnO green colored NIR reflective pigments was synthesized by sol-gel route. The dried gel precursor was calcined at different temperatures for 2 h (550 °C, 650 °C, 750 °C, 800 °C, and 850 °C), observing the formation of greenish pigments. The calcined pigments were characterized by thermogravimetry (TGA), Fourier transform infrared (FT-IR), and X-ray diffraction (XRD) to investigate the physio-chemical and structural properties. The synthesized pigments showed near-infrared (NIR) reflectance ability and a green color attributed to the formation of Cu-substituted cubic and hexagonal YInO3 structures. The pigments were embedded in PMMA based to assess their potential to develop cool roofs coatings. The pigments demonstrated slightly reduced NIR reflectance when embedded in the polymeric paste. The thermal properties were assessed by exposing the coatings under a xenon arc lamp to measure the heating up of the coatings containing the various pigments.