UV Transmission Research Articles

UV Transmission in Prebiotic Environments on Early Earth.

Ultraviolet (UV) light is likely to have played important roles in surficial origins of life scenarios, potentially as a productive source of energy and molecular activation, as a selective means to remove unwanted side products, or as a destructive mechanism resulting in loss of molecules/biomolecules over time. The transmission of UV light through prebiotic waters depends upon the chemical constituents of such waters, but constraints on this transmission are limited. Here, we experimentally measure the molar decadic extinction coefficients for a number of small molecules used in various prebiotic synthetic schemes. We find that many small feedstock molecules absorb most at short (∼200 nm) wavelengths, with decreasing UV absorption at longer wavelengths. For comparison, we also measured the nucleobase adenine and found that adenine absorbs significantly more than the simpler molecules often invoked in prebiotic synthesis. Our results enable the calculation of UV photon penetration under varying chemical scenarios and allow further constraints on plausibility and self-consistency of such scenarios. While the precise path that prebiotic chemistry took remains elusive, improved understanding of the UV environment in prebiotically plausible waters can help constrain both the chemistry and the environmental conditions that may allow such chemistry to occur.

Multiple birds with one stone: A new type of PPy/Fe3O4/rGO multifunctional composite fabric for wave absorption, UV resistance, anti-static and thermal insulation

To solve the problem of electromagnetic radiation pollution, it is especially important to develop electromagnetic wave-absorbing materials with excellent performance. The preparation of composite multifunctional textile materials with excellent wave-absorbing properties is one of the research hotspots for practical personal protection applications. In this work, PPy/Fe3O4/rGO polyester/cotton composite fabrics were prepared by impregnation, chemical reduction, chemical co-precipitation and in situ polymerization. When the thickness is 0.97 mm, the minimum reflection loss (RLmin) of PPy/Fe3O4/rGO polyester/cotton composite fabric is −12.12 dB, and the effective absorption bandwidth (EAB) is 4.7 GHz, which is excellent in wave absorption. Meanwhile, the PPy/Fe3O4/rGO polyester/cotton composite fabrics have excellent UV resistance (UV transmittance ratio of UVA and UVB bands as low as 0.02 %, UPF value of 100+), antistatic properties (static voltage half-life of 0.2 s), and excellent thermal management properties (thermal conductivity as low as 0.05796 W/(m·K)), and so on. The PPy/Fe3O4/rGO polyester/cotton composite fabrics prepared in this study are suitable for a variety of application scenarios, such as individual electromagnetic protection, individual protection in extremely cold environments, and individual heating physiotherapy, which is of great reference significance for the research of wearable individual protective textile materials.

Synthesis and characterization of high strength and ultraviolet transmitting silicone rubber reinforced by organic solvent‐soluble trimethylsiloxysilicate polymers (MQ and MTQ copolymers)

AbstractAdditional‐type liquid silicone rubber (ALSR) has poor mechanical properties, and conventional methods to reinforce it are at the cost of decreasing transparency. Here, vinyl MQ and fluorine‐containing MTQ silicone resins were synthesized by the sol–gel method. Then, high strength and ultraviolet (UV) transmitting ALSR were prepared using MQ and MTQ silicone resins as reinforcing agents, vinyl‐terminated silicone oil, and polydimethylmethylhydrosiloxane as matrix, respectively. The results show that the enhancement effect of MTQ silicone resin on the mechanical properties of ALSR resin is better than that of MQ silicone resin due to the vinyl content of MTQ silicone resin being higher than that of MQ silicone resin. Compared with pure ALSR, the tensile strength, Young's modulus, and Shore hardness of ALSR with 7 wt% MTQ silicone resin are enhanced by 435%, 127%, and 14%, respectively. The thermal stability of ALSR is slightly increased. The modified silicone rubber also has favorable transparency. Additionally, the MTQ/ALSR composites show higher UV transmittance than MQ/ALSR systems owing to the introduction of fluorine element increasing UV transmittance. The high strength and UV transmittance silicone rubber composites were prepared by using a small addition of MTQ silicone resin.

Fabrication of Multifunctional Nanocomposite Fiber Extracted from Sambucus nigra: Anti-nociceptive, Anti-inflammatory, Self-Cleaning, and UV Blocking.

This article describes how to extract chemical compounds from Sambucus nigra and make multifunctional nanofabric doping/undoping nano-zinc oxide particles using an electrospinning apparatus. The created sample was examined using field emission scanning electron microscope (FESEM), which revealed that the manufactured fibers have an approximate diameter of 35nm. An elemental mapping study also demonstrated the excellent distribution of nano-ZnO over the surface of the nanocomposite. The anti-nociceptive effect of the samples was studied, and the results suggested that the presence of Sambucus nigra caused pain prevention, and this effect demonstrated the anti-nociceptive effect in the samples studied by tail-flick experiments. Additionally, the anti-inflammatory properties of the samples were tested and showed favorable data results. Meanwhile, the self-cleaning of the prepared nanocomposites was studied. The results show that nano-zinc oxide doping has a direct impact on improving self-cleaning properties. Furthermore, ultraviolet (UV) transmission analysis of the samples showed that the prepared nanocomposites had excellent UV-blocking properties.

Applications and characterization of anti-browning enzymatically modified potato starch (EPS) film associated with chitosan (CTS)/L-Cys/citric acid (CA) on fresh-cut potato slices

This study explores the influence of incorporating L-cysteine (L-Cys), chitosan (CTS), and citric acid (CA) on the enzymatic modification of potato starch (EPS) films to enhance anti-browning properties. Four types of EPS composite films were evaluated for preserving fresh-cut potato slices at low temperatures to inhibit browning. Their thermal, physiochemical, mechanical, and digestibility properties were assessed. Results indicate that the addition of CTS, CA, and L-Cys improved the anti-browning activity of the EPS films by increasing film thickness and reducing water vapor permeability (WVP), oxygen transmission rate (OTR), ultraviolet (UV) transmittance, and tensile strength (TS). Furthermore, these additives improved the film's microstructure, resulting in reinforced intermolecular interactions, increased elongation at break, heightened crystallinity, enhanced thermal stability, and favorable gastrointestinal digestibility. Overall, EPS/CTS/L-Cys/CA composite films show promise as edible packaging materials with effective anti-browning properties.

Acclimatization and Foraging of Native Brazilian Stingless Bees in Arenas with Covering Materials of Different Spectral Properties.

The use of Meliponini for crop pollination in protected environments is practically non-existent. One of the reasons is the difficulty of acclimatizing Meliponini to the temperature and light conditions inside greenhouses. We investigated how covering materials used in greenhouses, which filter different intensities of ultraviolet (UV) light, affect the foraging behaviors, flight orientation, attraction to walls and ceilings, and mortality of Scaptotrigona cf. postica (Letreille), Frieseomelitta varia (Lepeletier), and Melipona quadrifasciata (Lepeletier). The experiments were conducted in 5.3 m3 arenas covered with four types of plastic films that do not polarize sunlight, with UV transmittance levels ranging from 0.1 to 54%, compared to a transparent glass control. The temperature inside the arenas varied between treatments, from 27 ± 3°C to 31 ± 2°C. All three species collected resources and returned to the colony, regardless of the covering material. However, the proportion of this behavior, the number of bees attracted to the ceiling and wall, and mortality varied among treatments and/or throughout the confinement days for each species. Melipona quadrifasciata and F. varia acclimatized better to the confined environments than S. cf. postica and showed consistent resource collection behavior throughout the confinement days in all tested materials, except for the one that filtered around 90% of UV. In all three species, the mortality gradually decreased throughout the confinement days. The results indicate that the choice of covering material, considering its optical characteristics, can be crucial to ensure greater effectiveness of the pollination services provided by stingless bees in protected systems.

Comparative study on the effects of chitosan, carrageenan, and sodium alginate on the film-forming properties of fish skin gelatin

Polysaccharides are commonly used to improve the film-forming properties of gelatin due to their wide range of sources, safety, and edible properties. However, there has been no systematic study comparing the effects of different polysaccharides on the film-forming properties of gelatin. Effects of chitosan, carrageenan, and sodium alginate on the optical properties, mechanical properties, thermal stability, hydrophilicity, and structure properties of gelatin films were systematically compared. Adding chitosan effectively reduced the ultraviolet transmittance of gelatin film. With an increase in chitosan concentration from 2 g/L to 8 g/L, the melting transition temperature (Tm) of gelatin film increased from 74 °C to 101 °C. Additionally, water vapor permeability decreased from 2.2 ± 0.23 (g.mm)/m2.h.kpa to 1.2 ± 0.18 (g.mm)/m2.h.kpa and water solubility decreased from 75% to 66%. Adding carrageenan and sodium alginate respectively increased the Tm of gelatin film to 92 °C and 84 °C; however, their addition reduced hydrophobicity and elongation at break for gelatin films. X-ray diffraction results suggested good compatibility between gelatin and all three polysaccharides while Fourier transform infrared spectrum results confirmed hydrogen bond interaction between gelatin and polysaccharides with a more orderly structure observed in gelatin films after adding polysaccharides.

UiO-66 uniformly assembled foldable polyimide films with high transmittance and excellent ultraviolet resistance

As a protective layer for the flexible solar cell, a flexible protective material should be of high transmittance, excellent ultraviolet (UV) resistance and mechanical property. Herein, a foldable transparent polyimide (PI) composite film assembled with the zirconium-based metal-organic frameworks (UiO-66-X, X = H, NH2, NO2) is prepared by the direct dispersion or in-situ growth methods. The results show that the transmittances of UiO-66-X@PI films (U@PI, NU@PI and OU@PI) prepared with the in-situ growth are higher than those of UiO-66-X/PI films prepared with the direct dispersion, and the former's mechanical properties are also better than those of the latter. This may be because that the UiO-66-X in the former are embedded into the PI matrix to construct multipoint bonding network. The U@PI exhibits stronger UV-resistance than the Pristine PI, NU@PI and OU@PI after 5000 equivalent sun hours (ESHs) UV irradiation. The attenuations of average transmittance and tensile strength for U@PI are 2.19 % and 18.68 %, respectively, which are only one half and one-third of those for the Pristine PI (4.59 % and 56.58 %), respectively. And the average transmittance of U@PI has been over that of the Pristine PI after 5000 ESHs UV irradiation. This may be because that the porous UiO-66 increases the UV transmission path and the electron-hole recombination center, thereby inhibits the destructive effect of UV.

Biodegradable, Strong, and Hydrophobic Regenerated Cellulose Films Enriched with Esterified Lignin Nanoparticles.

The scientific community is pursuing significant efforts worldwide to develop environmentally viable film materials from biomass, particularly transparent, high-performance regenerated cellulose (RC) films, to replace traditional plastics. However, the inferior mechanical performance and hydrophilic nature of RC films are generally not suitable for use as a substitute for plastics in practical applications. Herein, lignin homogenization is used to synthesize high-performance composite films. The esterified lignin nanoparticles (ELNPs) with dispersible and binding advantages are prepared through esterification and nanometrization. In the presence of ELNPs, RC films exhibit a higher tensile strength (110.4MPa), hydrophobic nature (103.6° water contact angle, 36.6% water absorption at 120min, and 1.127×10-12gcmcm-2s-1 Pa-1 water vapor permeability), and exciting optical properties (high visible and low ultraviolet transmittance). The films further display antioxidant activity, oxygen barrier ability, and thermostability. The films completely biodegrade at 12 and 30% soil moisture. Overall, this study offers new insights into lignin valorization and regenerated cellulose composite films as novel bioplastic materials.

UV/TiO2 photocatalysis as post-treatment of anaerobic membrane bioreactor effluent for reuse

Advanced oxidation processes have been widely applied as a post-treatment solution to remove residual organic compounds in water reuse schemes. However, UV/TiO2 photocatalysis, which provides a sustainable option with no continuous chemical addition, has very rarely been studied to treat anaerobically treated effluents. In the current study, the removal of organics and nutrients from an anaerobic membrane bioreactor (AnMBR) effluent is evaluated during adsorption and photocatalysis processes under various conditions of TiO2 dose and UV intensity and compared to the effluent from an aerobic membrane bioreactor (AeMBR). The sequence for preferential adsorption on TiO2 was found to be phosphorus, inorganic carbon and then ammonia/organic carbon were found. The competing effect between the organics and nutrients, along with the low UV transmission efficiency caused by the need for high doses of TiO2, ultimately compromise the organic removal efficiency in the AnMBR permeate. TiO2 dosage was found to have a greater impact than UV intensity on improving the overall removal performance as nutrients are competing for the adsorption site but are not photodegraded. Under the same operational condition, the UV/TiO2 photocatalysis displayed a higher removal efficiency of organic matter and phosphorus in the AeMBR effluent due to a lower initial organics concentration and absence of ammonia as compared to the AnMBR effluent.

Impact of production methods on properties of natural rosin added polylactic acid/sodium pentaborate and polylactic acid/calcium carbonate films

Nowadays biopolymers play an important role in packaging materials due to their protection properties against physical and chemical degradation or mechanical resistance. In this study, sodium pentaborate anhydride (B5NaO8), eggshell (CaCO3) nanoparticles, and natural rosin additives were introduced to pure PLA to produce a biofilm protecting from UV rays. The impact of the preparation method of hybrid biocomposite films was carried out based on the polymer casting method and using in the first case only magnetic mixing whereas magnetic mixing coupled with ultrasonic homogenizer was used in the second case. All biocomposite films were obtained for a nanoparticle content fixed at 7.5 wt% and various rosin rates (1, 5, 10, and 40 wt%). This study aims to expand the UV protection zone in PLA films. The thermal and mechanical properties, transmittance of UV–visible rays, microstructure analysis, and contact angle values were evaluated to detect the effect of the preparation method on the final properties. The results showed that the homogeneous distribution of the particles was more effective using an ultrasonic homogenizer. The increase of the rosin amount exhibited a reduction of the UV–visible light transmittance and the wettability was observed, demonstrating a potential use of these films in packaging.

Structure and properties of chlorogenic acid-loaded polylactide fiber prepared by melt spinning

Polylactide/chlorogenic acid (PLA/CGA) blends with different weight ratios were prepared by melt mixing, and corresponding PLA/CGA fibers were produced via a two-step melt spinning process. For PLA/CGA blends, CGA was distributed uniformly in the PLA matrix. The intermolecular interactions between CGA and PLA existed. The viscosity of PLA/CGA blends was much lower than that of neat PLA. With the increase of CGA content, the viscosity of PLA/CGA blends decreased. As the CGA content increased, the crystallinity of both PLA/CGA blends and fibers decreased. In addition, the tensile strength of PLA/CGA fibers was slightly lower than that of neat PLA fiber. For PLA/CGA fibers, the 6-fold drawn PLA/CGA fiber with 3 % CGA owned the highest tensile strength of 420 MPa. The ultraviolet (UV) resistance of PLA/CGA fibers were enhanced significantly by the introduction of CGA. When the CGA content was not <3 %, the UV transmittance of PLA/CGA fibers was <8 %. Moreover, PLA/CGA fibers exhibited good antioxidant properties. PLA/CGA fibers with 10 % CGA owned the highest antioxidant rate of >90 %. In addition, the 6-fold drawn PLA/CGA fiber with 10 % CGA presented excellent release performance with a 7-day cumulative CGA release rate of 19 %.

Anti-moisture, anti-bacterial cellulosic triboelectric materials enabled by hydroxyl coordination effect

Owing to their low cost, customizability, and environmental stability, cellulosic triboelectric materials have emerged among polymer materials. However, the rich hydrogen bonding network inherent in cellulose limits its polarity and electron-donating ability, and charge dissipation caused by the hygroscopicity of the hydroxyl-rich groups limits its application as a triboelectric material. In this study, a more convenient, economical, and environmentally friendly "stent surgery" strategy was adopted. The wetting and swelling of fiber molecules allowed Cu (II) coordination with hydroxyl groups in nanocellulose. The coordination effect of cellulose hydroxyl groups weakens the intermolecular hydrogen bonding network, leading to an increase in the molecular dipole moment and the formation of new polar regions to regulate its space charge distribution, which significantly improved the electron-supplying capacity of the nanocellulose materials, and the maximum output power density increased by a factor of 2.78 (from 45 to 125 μW cm−2). Notably, the CNF-Cu (II) triboelectric material demonstrated excellent antimicrobial (>99%) and UV transmittance (<8%) as well as resistance to humidity interference, exhibiting only 5.9% voltage output loss at high humidity (90% RH). The design of this study provides new approaches for cellulose polarity modulation and energy harvesting adapted to harsh environments.

Poly (Lactic Acid) Cellulose Biocomposite Films as Potential Antimicrobial Food Packaging Material

Polylactic acid (PLA)-cellulose bio-composites were developed by incorporating Aloe vera (A. vera) leaf gel at ratios of 100/50 and 50/50. This study aimed to evaluate their physico-chemical, barrier, and antibacterial properties for potential application in sustainable food packaging. Different composite films were prepared and characterized by Fourier-transform infrared (FTIR) spectroscopy, Scanning electron microscopy (SEM), mechanical testing, water absorption, and Ultraviolet (UV) transmission measurements. Their antibacterial activity against E. coli, P. aeruginosa, and S. aureus was assessed through agar diffusion and broth dilution assays. The presence of cellulose significantly affected the properties of the composite films. The 50/50 blend exhibited better chemical resistance and barrier properties compared to the 100/50 blend, highlighting the influence of cellulose content. Both ratios demonstrated promising antibacterial activity against all three target bacteria, while the 50/50 ratio showing pronounced inhibition against E. coli. These PLA-cellulose bio-composite films, with their combined UV-protective and antibacterial properties, present a sustainable and potential alternative to conventional food packaging materials, contributing to a reduced environmental pollution.

New extreme ultraviolet transmission measurements of two thin-film filters for imaging of plasmaspheric cold ions

New extreme ultraviolet transmission measurements of two thin-film filters for imaging of plasmaspheric cold ions

Enhancing polyamide fabric performance through green reduction of graphene oxide for superior ultraviolet protection and electrical conductivity

AbstractIn this study, a polyamide warp‐knitted fabric was treated with a graphene oxide (GO) aqueous dispersion using a laboratory‐type Jigger dyeing machine. Subsequently, the GO underwent a chemical reduction process, employing rosehip extract powder as a nature‐based reducing agent. The effect of reduction time (12 and 24 h) was investigated. The study involved an examination of the surface morphology, colour coordinates, and colour difference of both the GO coated and reduced graphene oxide (RGO) coated fabrics. Additionally, the colour fastness against rubbing was assessed. Furthermore, electrical resistivity measurements were conducted on the GO‐coated polyamide‐6,6 fabric both before and after the reduction process. The ultraviolet (UV) transmittance and ultraviolet protection factor (UPF) of both GO‐coated and reduced fabrics were determined. The study also explored the effect of the washing process on colour properties, electrical resistivity, and UPF. Notably, the lowest electrical surface resistivity and the highest UPF rating were obtained as 1.20 × 102 kΩ/sq and 50+ after the reduction process. Additionally, after the washing process, the electrical surface resistivity increased, while the UPF rating remained 50+, indicating excellent UV protection.

Guidance of ultraviolet light down to 190 nm in a hollow-core optical fibre.

We report an anti-resonant hollow core fibre with ultraviolet transmission down to 190 nm, covering the entire UV-A, UV-B and much of the UV-C band. Guidance from 190 - 400 nm is achieved apart for a narrow high loss resonance band at 245 - 265 nm. The minimum attenuation is 0.13 dB/m at 235 nm and 0.16 dB/m at 325 nm. With an inscribed core diameter of ∼12 µm, the fibre's bend loss at 325 nm was 0.22 dB per turn for a bend radius of 3 cm at 325 nm.

Improving fourth harmonic generation performance by elevating the operation temperature of ADP crystal.

In current inertial confinement fusion (ICF) facilities, potassium dihydrogen phosphate (KH2PO4, KDP) type crystals are the only nonlinear optical (NLO) materials that can satisfy the aperture requirement of the ICF laser driver. Ammonium dihydrogen phosphate (NH4H2PO4, ADP) crystal is a typical isomer of KDP crystal, with a large nonlinear optical coefficient, high ultraviolet transmittance, and large growth sizes, which is an important deep ultraviolet (UV) NLO material. In this paper, we investigated the effect of ADP temperature on its fourth-harmonic-generation (FHG) performance. When the temperature of the ADP crystal was elevated to 48.9 °C, the 90° phase-matched FHG of the 1064 nm laser was realized. Compared with the 79° phase-matched FHG at room temperature (23.0 °C), the output energy at 266 nm, conversion efficiency, angular acceptance, and laser-induced damage threshold (LIDT) increased 113%, 71%, 623%, 19.6%, respectively. It shows that elevating ADP temperature is an efficient method to improve its deep UV frequency conversion properties, which may also be available to other NLO crystals. This discovery provides a very valuable technology for the future development of UV, deep UV lasers in ICF facilities.

Characterization of single-crystal phenothiazine synthesized using the vertical Bridgman method

Abstract A bulk organic single crystal of phenothiazine measuring 65 mm in length and 10 mm in width was grown using the single zone vertical Bridgman technique (VBT), which was visible to the naked eye. Powder X-ray diffraction, also known as XRD, was used in order to perform crystal structural verification on the manufactured crystal. The Fourier transform infrared spectroscopy (FT-IR) approach was used in order to ascertain the crystals’ respective vibrational frequencies. In order to evaluate the single crystal’s crystalline perfection and optical quality, high-resolution X-ray diffraction rocking curve measurement (HRXRD) and UV transmittance spectrum analysis were used. So as to investigate the nonlinear optical (NLO) activity of the generated single crystals, a Q-switched and pulsed Nd: YAG laser was used in the research. This led to the discovery of the SHG efficiency. The single crystal’s mechanical strength was evaluated using Vicker’s microhardness measurement, which provided an approximation of the true value. Furthermore, the single crystal was examined and reported for its optical birefringence, photoluminescence, and refractive index.

Flavonoid‐based yellow dye extract from safflower (Carthamus tinctorius L.) combined with chitosan for anti‐bacterial and ultraviolet‐protective functionalisation of silk

AbstractIn the modern period, scientists are interested in the functional properties of natural materials. The present study is the first report on the use of safflower (Carthamus tinctorius L.) yellow dye extract combined with chitosan bio‐mordant for enhancing the anti‐bacterial and ultraviolet‐protective activities of silk. The presence of flavonoid‐based compounds in the dye extract was verified using liquid chromatography–mass spectrometry, Fourier transform‐infrared spectroscopy, and ultraviolet‐visible techniques. Moreover, alum mordant was also utilised in the silk dyeing process to compare the efficiency of bio and metallic mordanting agents. Experiment outcomes revealed that the chitosan mordanted‐dyed silk sustained adequate fastness after being tested by washing, light, wet‐rubbing, and dry‐rubbing. In addition, superb bacterial inhibition percentages of 89% and 76% against Escherichia coli and Staphylococcus aureus, individually, were accomplished. Furthermore, the ultraviolet‐protective behaviour of this silk sample was demonstrated with a 50+ ultraviolet protection factor and low‐grade ultraviolet transmittance. This study reveals the great performance of an organic flavonoid dye as a sustainable and environmentally‐friendly substance for dyeing and functionalising silk, as well as the efficacy of a green mordant over a metallic mordant in increasing the dyeability and functional activities of silk.