Chemical Technique Research Articles

Non‐destructive quantitative analysis of melt inclusions in extraterrestrial samples: Case study of chassignite via nanoscale X‐ray computed tomography

AbstractEstimation of the composition of planetary rocks and minerals is crucial for understanding their formation processes. In this study, we present the application of X‐ray nano‐computed tomography (nano‐XCT) for non‐destructive three‐dimensional (3‐D) phase analysis and estimation of phase abundances in rare Martian meteorite samples, specifically chassignite Northwest Africa (NWA) 2737. We determined the most suitable laser power for minimizing artifacts and maximizing phase contrast. By utilizing nano‐XCT, we successfully identified and segmented primary phases in the bulk meteorite sample. Additionally, we were able to locate and segment crystallized silicate melt inclusions within the meteorite. The phase abundances in bulk NWA 2737 and within melt inclusions calculated using nano‐XCT were in good agreement with previous studies that used thin section calculations, demonstrating the reliability of nano‐XCT as a non‐destructive alternative for estimating bulk phase abundances in rare samples. This study develops a benchmarking protocol and demonstrates the efficacy of nano‐XCT as a non‐destructive technique for generating an overview of phase distribution and assemblages of melt inclusions within rare samples. Future research can benefit from combining non‐destructive 3‐D phase assemblage estimations with non‐destructive 3‐D chemical analysis techniques to achieve a fully non‐destructive parental magma composition estimation of rare cumulate samples.

Synthesis of Gold Nanoparticles over CoAl Mixed Oxide for Ethanol Oxidation Reaction.

Catalytic total oxidation is an effective technique for the treatment of industrial VOCs principally resulting from industrial processes using solvents and usually containing mono-aromatics (BTEX) and oxygenated compounds (acetone, ethanol, butanone). The aim of this work is to deposit gold nanoparticles on CoAl mixed oxide issued from layered double hydroxide (LDH) precursor by using the deposition precipitation (DP) method, which is applied with two modifications, labeled method (A) and method (B), in order to enhance the interaction of the HAuCl4 precursor with the support. Method (A) involves the hydrolysis of the HAuCl4 precursor after addition of the support, while in method (B), the gold precursor is hydrolyzed before adding the support. The two methods were applied using as support the CoAl mixed oxide and the LDH precursor. Samples were characterized by several physical chemical techniques and evaluated for ethanol total oxidation. Method (B) allowed the ethanol oxidation activity to be enhanced for the resulting Au/CoAlOx catalysts thanks to the high surface concentration of Co2+ and improved reducibility at low temperature. The presence of gold permits to minimize the formation of by-products, notably, methanol, allowed for a total oxidation of ethanol at lower temperature than the corresponding support.

Investigation of dextran-coated magnetic nanoparticles encapsulated by medication and modified with folate for targeted drug delivery: Invitro and docking studies

In this study, we synthesized dextran (DEX)-coated iron oxide (Fe3O4) and encapsulated it by the anticancer drug cisplatin (CP). This nano-composite functionalized with folic acid (FA) molecules for targeted delivery. These nanoparticles (NPs) were then used as nanocarriers for the targeted administration of CP for treating thyroid tumor cancer. The Fe3O4 NPs were synthesized using a chemical technique. The development of the Fe3O4@DEX-CP-FA nanosystem was achieved using a reverse microemulsion technique. The morphological features of the NPs were characterized using several methods, including dynamic light scattering, atomic force microscopy, vibrating sample magnetometry, high-resolution transmission electron microscopy, and field emission scanning electron microscopy. The docking study has verified that nanoparticles have anti-proliferative effects in thyroid cancer by attaching strongly to molecular targets. The MTT test evaluated the effects of a curative Fe3O4@DEX-CP-FA effect on cancerous and non-cancerous cell lines. The results obtained from the formulation of Fe3O4@DEX-CP-FA revealed the presence of spherical particles with an average size of 107.3 nm, a zeta potential of −28.7 mV, and a polydispersity value of 0.055 mV. Depending on the dose, the nanosystem exhibited cytotoxic effects on thyroid tumor (TT) and normal human thyroid (NHT) cell lines. The study findings indicate that Fe3O4@DEX-CP-FA demonstrated sustained antitumor efficacy while not revealing a harmful impact on normal cells.

Direct Synthesis of Calcium Lactate through the Reaction of Glycerol with Calcium Hydroxide Catalyzed by Bimetallic AuCu/SiO2 Nanocatalysts

Bimetallic AuCu/SiO2 nanosized catalysts were prepared using the wet chemical reduction technique. From among Au0.1–1.5Cu10/SiO2 catalysts, the Au0.5Cu10/SiO2 catalyst gave the highest yield of calcium lactate of 87% at a glycerol conversion of 96% when the reaction of glycerol with calcium hydroxide at a mole ratio of calcium hydroxide to glycerol of 0.8:1 was conducted under an anaerobic atmosphere at 200 °C for 2 h. The interactions between metallic Au0 and Cu0 nanoparticles facilitate calcium lactate formation. The simulation of glycerol consumption rate with an empirical power-function reaction kinetics equation yielded a reaction activation energy of 44.3 kJ∙mol−1, revealing that the catalytic reaction of glycerol with calcium hydroxide to calcium lactate can be conducted by overcoming a mild energy barrier. The synthesis of calcium lactate through the catalytic reaction of glycerol with calcium hydroxide on a bimetallic AuCu/SiO2 nanosized catalyst under a safe anaerobic atmosphere is an alternative to the conventional calcium lactate production technique through the reaction of expensive lactic acid with calcium hydroxide.

Actinomycetes as a Possible Source of Bioremediation of Heavy Metal Cadmium from Contaminated Soil

Annually, a significant volume of chemicals, encompassing fertilizers and pesticides, is administered to agricultural soils. Using pesticides and fertilizers, agricultural practices contribute to heavy metal Cadmium (Cd), Copper (Cu), Lead (Pb) and Zinc (Zn) pollution. Heavy metals and pesticides are high at the peak of ecological contaminants, presence of this has introduced grave risks to the health of the population and agronomics. Among heavy metals, cadmium (Cd) is recognized for its high mobility in various environmental settings. Cd has a deleterious effect on plant phenotypic, cytotoxicity (e.g., lowering chlorophyll concentration and limiting photosynthetic effectiveness), and metabolic activities (e.g., chlorosis and necrosis). Microbial bioremediation by using microorganisms is one of the secure, pure, cost operative and eco-friendly technology for decontaminating polluting sites as compared to physical and chemical techniques. Among microbes, Actinobacteria hold a paramount position, serving as key players in numerous biological processes, utilize toxins as carbon source and turn into high concentrations of pesticides, chemical complexes and heavy metals into commercially viable antibiotics, enzymes, proteins, and plant growth promoting hormones. This study is an effort to explore the potent cadmium resistance actinomycetes to reduce cadmium levels to enhance degradation. For this purpose, 53 actinomycetes strains were tested for heavy metal resistance and tolerance to Cadmium against different concentrations. After secondary screening Four potent isolate have the potential to grow at 1000 mg/L concentration of Cadmium in the medium. When they are able to grow on heavy metal containing media it could be beneficial for reduction and elimination of toxic metals from contaminated environment. When it comes to achieving a suitable level of metal tolerance, this potent powerful actinomycetes strain Streptomyces pactum have been identified to be promising.

Sequential, Electrochemical-Photochemical Synthesis of 1,2,4-Triazolo-[4,3-a]pyrazines.

1,2,4-triazolo-[4,3-a]pyrazine was prepared via a two-step electrochemical, photochemical process. First, a 5-substituted tetrazole is electrochemically coupled to 2,6-dimethoxypyrazine to yield 1,5- and 2,5- disubstituted tetrazoles. Subsequent photochemical excitation of the 2,5-disubstituted tetrazole species using an ultraviolet lamp releases nitrogen gas and produces a short-lived nitrilimine intermediate. Subsequent cyclization of the nitrilimine intermediate yields a 1,2,4-triazolo-[4,3-a]pyrazine backbone. The scope of this reaction was explored using various tetrazoles and pyrazines. Materials produced were identified using chemical analytical techniques and computationally studied for potential application as an insensitive energetic material.

Chemical Recycling of Plastic Waste from Different Polymers: New Trends

Background For decades, the amount of global plastic waste has been increasing at an alarming level. Traditional landfill and incinerator treatments, on the other hand, result in air pollution and wastage of valuable land. Method This study examined recent advances in the recycling and recovery of plastic waste. A special emphasis was placed on trash derived from polyolefinic sources, which accounts for a substantial part of plastic products used in the daily lifecycle. The mechanical and chemical systems and technologies for plastic waste treatment were detailed and explored in this study. To ensure a comprehensive study, sixty-five (65) papers were carefully selected. The selected papers were published during the period 2015-2023. These papers were searched using web search engine Google Scholar and PubMed database and reviewed to derive meaningful insights. Results The findings determined that chemical recycling of plastic waste is a critical possibility to reduce marine and terrestrial pollution and enable the idea of circular economy to be implemented in today's world. Plastic waste poses both obstacles and opportunities to communities, independently of their level of environmental awareness or technical advancement. Moreover, mechanical processes utilize a variety of waste products as feedstock. Depending on their source, shape, and usage, these waste products can be reduced in size to a more acceptable shape and form (pellets, flakes, or powders). Conclusion Advanced thermo-chemical treatment methods encompass a wide range of technologies that produce either fuels or petrochemical feedstock. Although mechanical recycling schemes are well known and commonly used, many chemical recycling treatment techniques are more productive and widely used due to their economic benefits.

Chemical treatment in 3D dental model production for clear aligners via additive manufacturing: a comprehensive evaluation

PurposeStereolithography (SLA) additive manufacturing (AM) technique has enabled the production of inconspicuous and aesthetically pleasing orthodontics that are also hygienic. However, the staircase effect poses a challenge to the application of invisible orthodontics in the dental industry. The purpose of this study is to implement chemical postprocessing technique by using isopropyl alcohol as a solvent to overcome this challenge.Design/methodology/approachFifteen experiments were conducted using a D-optimal design to investigate the effect of different concentrations and postprocessing times on the surface roughness, material removal rate (MRR), hardness and cost of SLA dental parts required for creating a clear customized aligner, and a container was constructed for chemical treatment of these parts made from photocurable resin.FindingsThe study revealed that the chemical postprocessing technique can significantly improve the surface roughness of dental SLA parts, but improper selection of concentration and time can lead to poor surface roughness. The optimal surface roughness was achieved with a concentration of 90 and a time of 37.5. Moreover, the dental part with the lowest concentration and time (60% and 15 min, respectively) had the lowest MRR and the highest hardness. The part with the highest concentration and time required the greatest budget allocation. Finally, the results of the multiobjective optimization analysis aligned with the experimental data.Originality/valueThis paper sheds light on a previously underestimated aspect, which is the pivotal role of chemical postprocessing in mitigating the adverse impact of stair case effect. This nuanced perspective contributes to the broader discourse on AM methodologies, establishing a novel pathway for advancing the capabilities of SLA in dental application.

New design of eco-friendly Catalytic Electro - Photo Desulfurization process for real diesel fuel

Recently, due to the refineries processes considerations and environmental issues major limitations have been imposed on the sulfur compounds presented in petroleum distillates. Therefore, to reduce the sulfur compounds to minimum levels and to meet the global legislations, many of techniques were used, among them electro chemical photo desulfurization technique was used here. In this study, DBT was removed using electro chemical photo desulfurization over electrodes of titanium and stainless steel using Fe2O3/TiO2 as a catalyst under different temperatures (45, 60, 75 ℃), current density (10, 15, 20 A/m2), electrolyte concentration (25, 35, 45 wt%). The catalyst was characterized by different advanced surface techniques such as N2- adsorption-desorption, SEM-EDX, FTIR, and XRD. The reaction kinetic parameters (reaction order and activation energy) were estimated based on the experimental runs. According to the results obtained, this technique was revealed an efficient method with highest removal of 93.79% achieved using Fe2O3/TiO2 under the best of experimental operating conditions at 75 ℃, 20 A/m2 and 35 wt% of temperature, current density and electrolyte concentration respectively. It can be concluded that the electro chemical photo oxidative desulfurization reaction followed was pseudo 1st order and 41.67 kJ/mole activation energy over titanium dioxides catalyst.

Tin Oxide Bilayer as Effective Electron Transport Layers for Efficient and Stable Perovskite Solar Modules

Tin oxide (SnO2) is one of the most promising electron transport layers (ETL) for the commercialization of perovskite solar cells (PSCs) due to its excellent electron mobility and high transparency, along with its low processing temperature. However, the inherent defects, nonuniform coating, and poor surface morphology of SnO2 may be detrimental to the physicochemical properties, such as conductivity and electron mobility at the interface, lead to a decrease in the open‐circuit voltage (VOC) and a reduction in device stability. In this study, a method that combines atomic layer deposition and chemical bath deposition techniques to solve these issues is presented. The presence of bilayer ETLs enhances the coverage of the SnO2 film and optimizes the morphology of the buried surface of perovskite, which not only facilitates the interfacial charge transfer but also suppresses recombination reactions. As a result, a significant increase in VOC and efficiency has been achieved compared to devices with only a single layer. Additionally, the large‐area perovskite solar module (active area: 48.0 cm2) achieves a champion efficiency of 17.9%. The PSCs retain more than 93% of their initial efficiency after 700 h of continuous operation under 1‐sun illumination and 25 °C.

Symmetry-Reduction Enhanced Polarization-Sensitive Photoresponse Based on One-Dimensional van der Waals Materials.

Designing high-performance polarization-sensitive photodetectors is essential for photonic device applications. Anisotropic one-dimensional (1D) van der Waals (vdW) materials have provided a promising platform to that end. Despite significant advances in 1D vdW photonic devices, their performance is still far from delivering practical potential. Herein, we propose the design of high-performance polarization-sensitive photodetectors using unique 1D vdW materials. By leveraging the chemical vapor transport technique, we successfully fabricate high-quality 1D vdW Nb2Pd1-xSe5 (x = 0.29) nanowires. The 1D vdW Nb2Pd1-xSe5 photodetector exhibits a high mobility of ∼56 cm2/(V s) and superior photoresponse performance, including a high responsivity of 1A/W and an ultrafast response time of ∼8 μs under 638 nm illumination. Moreover, the 1D vdW Nb2Pd1-xSe5 photodetector demonstrates excellent polarization-sensitive photoresponse with a degree of linear polarization (DOLP) up to 0.85 and can be modulated by adjusting the gate voltage, laser power density, and wavelength. Those exceptional performance are believed to be relevant to the symmetry-reduction induced by the partial occupation of Pd sites. This study offers feasible approaches to enhance the anisotropy of 1D vdW materials and the modulation of their polarization-sensitive photoresponse, which may provide deep insights into the physical origin of anisotropic properties of 1D vdW materials.

Investigate the Electrical and Structural Characteristics of the Si-ZnO Diode

Silicon-zinc oxide (Si-ZnO) junction has been prepared using the chemical bath technique. The zinc oxide layer was examined using different techniques, including X-ray spectroscopy and a UV-visible spectrophotometer. The ZnO film images show that the films are homogeneous with an average grain size of 70 nm, while the X-ray spectrum shows that the layers are amorphous with some crystalline phase peaks appearing between 2θ=20° and 35°, which belong to ZnO. Transmittance, absorbance and extinction coefficient were varied over the visible light wavelength range, and the energy gap of the films was about 2.6 eV. In both forward and reverse bias, the junction revealed diode characteristics. The influence of light on the current intensity was evident and reached about 240 mA compared to the current intensity in the dark state. Also, the current intensity of the diode increased at each applied voltage with the increase in the intensity of the light shining on it.

IoT-Enabled Water Quality Monitoring and Alum Dose Determining System

The water treatment process involves a series of physical, chemical, and biological techniques and methods designed to remove contaminants, impurities, and undesirable substances from raw or untreated water to make it safe, clean, and usable. Adverse weather conditions, such as rainy seasons and floods, present significant challenges, and difficulties to the water treatment process. Alum is mainly used for reducing the turbidity of the water in the treatment process. In Sri Lanka, all water treatment plants use the Jar Test to determine the Alum dosage manually. They conduct Jar Tests to measure raw water quality in their laboratories. The Alum addition valve is set to a pre-determined quantity and the value is decided based on the experience of the technicians. Since there is no specific formula, the presence of an experienced technician is required to determine alum dosage using the Jar test. Thus, this study intends to propose an automated system for determining the optimum Alum quantity to be added to a given raw water sample. This is achieved by designing an Internet of Things (IoT)-enabled sensing device for measuring the water quality, which feeds data to a Machine Learning Model trained to predict the Alum quantity to be added. The task of the Machine learning model is to identify the pattern of raw water parameters and Alum dosage. By doing this, a could be provided a guideline for determining alum dosage instead of a manual Jar test and removed the necessity of experienced technician support always. A user-friendly web interface will allow the operators to customize the parameters according to the requirement and display a detailed analysis report. The predetermined quantity of Alum is transmitted to the output Alum adding value, to enhance its performance as an automated control rather than doing the addition process manually. This is a conceptual study on how to determine the Alum dosage using Raw water parameters and past experiment results.

Bioactivities of Jojoba Oil Beyond Skincare.

Jojoba oil, which is extracted from jojoba plant seeds that are native to North America, possesses a unique molecular structure and is distinct from other oils. Unlike typical oils, which mostly contain triglycerides, jojoba oil is composed of long monounsaturated esters, affording it exceptional properties and is valuable across cosmetics, chemicals, and pharmaceuticals. While jojoba oil is prevalent in beauty and skincare today, its seeds and oil have ancient roots in folk medicine, used for treating skin and scalp issues, wounds, sore throats, obesity, and even cancer, while enhancing immunity and fostering hair growth. Modern research underscores jojoba oil's pharmacological versatility, demonstrating antioxidant, antidiabetic, anti-acne, anti-inflammatory, antipyretic, and antibacterial properties. Notably, there has been a surge in its utilization in pharmaceuticals, particularly in topical, transdermal, and parenteral formulations. This review provides a comprehensive overview of jojoba oil, encompassing its chemical composition, extraction techniques, health advantages, and pharmaceutical application developments.

High performance of SrCo1-xZrxO3-δ perovskite cathodes for IT-SOFCs

Stabilization of a tetragonal perovskite structure in the SrCoO3-δ system at room temperature has been achieved through wet chemical techniques, and it has been successfully tested in Solid Oxide Fuel Cells (SOFCs). Chemical substitutions at the Co position were carried out by introducing different amounts of zirconium (SrCo1-xZrxO3−δ; x = 0.05, 0.08 and 0.11) to destabilize the columns of CoO6 octahedra sharing faces in the competitive 2H-hexagonal phase. The crystal structure was studied by X-ray diffraction (XRD) and neutron powder diffraction (NPD) at 25 °C and correlated with mechanical and electrical properties. Chemical compatibility studies between the samples and the La0.8Sr0.2Ga0.83Mg0.17O3-δ (LSGM) electrolyte revealed not interaction at high temperatures. Dilatometric analysis measurements showed a compatible thermal expansion with the LSGM electrolyte over the entire temperature range, demonstrating good mechanical compatibility. Furthermore, the relatively high conductivity values (∼83 S cm-1 at 850 °C) indicated their suitability as cathodes in SOFCs. Finally, test cells prepared with an electrolyte (LSGM) supported configuration provided a maximum output power exceeding 600 mW/cm2 using pure H2 as fuel at 850 °C. Importantly, the performance of the cathode materials did not degrade after extended operation at this temperature.

Co3O4 derived ZnO: An effective electrocatalyst for oxygen evolution reaction in alkaline media

The growing accessibility of hydrogen and renewable energy sources has led to a rising significance of cobalt oxide (Co3O4)-based electrocatalysts in the context of effective electrochemical water splitting. Among two-half cell reactions, oxygen evolution reaction (OER) is more complicated and sluggish in behaviour. We present a composite material based on cobalt oxide-derived zinc oxide (Co3O4@ZnO) prepared through a wet chemical technique to overcome this challenge. The as-prepared materials are analyzed for crystallinity, morphology, and chemical bonding through X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), high resolution transmission electron spectroscopy (HRTEM), and Fourier transform infrared (FTIR) spectroscopy, respectively. The optimized electrocatalyst reveals higher electrochemical performance for OER with an overpotential value of 262 mV at 10 mA/cm2 current density, Tafel slope value of 59 mV/dec, and charge transfer resistance (Rct) of 72 Ω. Moreover, the electrochemical active surface area (ECSA) is calculated as 320 cm2. Notably, the desired electrocatalyst shows the stability of 50 h at 10 and 20 mA/cm2 current densities. The as-prepared catalyst (Co3O4@ZnO) with effective electrochemical features can be a potential candidate for energy conversion applications toward a sustainable society.

Forensic Fingerprint Analysis

Fingerprint evidence found at crime scenes provides vital impressions left when these skin secretions touch surfaces clues in serial criminal investigations. A fingerprint identification system employing deep machine learning and Convolutional Neural Networks (CNNs) could automate the analysis process. Images obtained from various physical and chemical crime scene investiga2tion techniques are entered into the database. However, partial latent prints lifted from scenes are often difficult to classify. The system operates in three phases: preprocessing fingerprint images, feature extraction, and matching. Preprocessing enhances image quality before feature extraction identifies distinctive minutiae points - ridge endings and bifurcations. False minutiae removal further refines the data. The preprocessed fingerprint data serves as input to train and test the CNN model. As the system persist due to the immutable individuality of fingerprint ridge arrangements [5]. While criminals attempt concealment, fingerprint traces stubbornly remain where other evidence would dissipate [6]. Without these durable biometric markers, crime scenes would often lack the critical traces needed to connect acts to perpetrators [7]. Latent prints lifted from crime scenes first undergo photographic documentation and chemical enhancement techniques in order to visualize trace details [8]. Computer analysis then further improves clarity, isolating minute identifying features known as minutiae [9]. Algorithmic extraction of differentiating traits classifies new latent prints, it continuously incorporates the prints enables training of automated comparison systems using along with confirmed suspect identity matches to improve accuracy. Automated classification and matching facilitate identification. The approach scales as the database grows in size without proportionate growth in human effort. Rapid fingerprint evidence analysis accelerates investigations, potentially solving more crimes by linking serial cases through a central digital repository. I aimed to restate the key technical ideas and flow using alternative vocabulary and phrasing while preserving semantic meaning. Please let me know if you need any clarification or have additional requirements for rephrasing the passage.

Standardization of Myristicin in Nutmeg (Myristica fragrans Houtt.) Fruit using TLC-Densitometric Method

Background: Myristica fragrans Houtt. (Myristicaceae family), with the main content of myristicin, has been immensely used in herbal medicine. Standardization is essential to ensure the safety of natural extracts and the quality of herbal medicines using various chemical analysis techniques. Method validation is necessary to ascertain the reliability and reproducibility of the method. Myristicin is a member of the phenylpropene group, a natural organic compound found in small amounts in nutmeg fruit, which has pharmacological effects. Objective: This study aims to determine the myristicin content in nutmeg fruit using TLC-Densitometry. Methods: Determination of myristicin in nutmeg fruit extract was performed using TLC-Densitometry with silica GF254 as stationary phase, mobile phase n-hexane: ethyl acetate (8:2 v/v), and spot visualized at 285 nm. In this study, the content of myristicin in nutmeg fruit was determined using compendial methods (AOAC), thus requiring method verification with parameters including selectivity, linearity, precision, LOD, and LOQ. Results: The validation of this method showed good linearity and selectivity with y = 0.0001x + 0.0226 (r = 0.9996) and 1.53 (>1.5), respectively. The LOD and LOQ results were low with values of 0.11 μg/spot and 0.33 μg/spot, respectively. The percentage coefficient of variation for precision was below the requirement value of not more than 4%. The average myristicin content in nutmeg fruit extract was approximately 0.0017 ± 0.0003% (w/w). Conclusion: The developed method was valid and sensitive for the quantification of myristicin content in nutmeg fruit.

Parsec-scale cosmic-ray ionisation rate in Orion

Cosmic rays are a key component of the interstellar medium because they regulate the dynamics and chemical processes in the densest and coldest regions of molecular clouds. Still, the cosmic-ray ionisation rate of H$_2$ (crir ) is one of the most debated parameters characterising molecular clouds because of the uncertainties in the adopted chemical networks and analysis techniques. This work aims to homogeneously estimate the crir at parsec scales towards the Orion Molecular Clouds OMC-2 and OMC-3. We explore the change in crir across a whole star-forming region by probing a range of column densities taht has never been explored before. The significant increase in statistics obtained by studying an entire region allows us to place stronger constraints on the range of crir values and exploit its connection with the physical properties of the interstellar medium. The most recent crir estimates are based on o$-$H$_2$D$^+$, which is a direct product of the interaction between cosmic rays and H$_2$ in cold clouds. Since observations of o$-$H$_2$D$^+$ are challenging, we proxy its abundance through CO depletion by employing C18O (2$-$1) observations towards OMC-2 and OMC-3, taking advantage of the existing correlation between the two parameters. Using additional observations of HCO$^+$ (1$-$0) and DCO$^+$ (3$-$2), we determine the deuteration fraction, and we finally derive the map of crir in these two regions. The C18O depletion correlates with both the total column density of H$_2$ and the N$_2$H$^+$ emission across OMC-2 and OMC-3. The obtained depletion factors and deuteration fractions are consistent with previous values obtained in low- and high-mass star-forming regions. These two parameters additionally show a positive correlation in the coldest fields of our maps. We derive cosmic-ray ionisation rates of $ $ s$^ $. These values agree well with previous estimates based on o$-$H$_2$D$^+$ observations. The crir also shows a functional dependence on the column density of H$_2$ across a full order of magnitude ($ $ cm$^ $). The estimated values of crir decrease overall for increasing $N( H_2 $), as predicted by theoretical models. The results delivered by our approach are comparable with theoretical predictions and previous independent studies. This confirms the robustness of the analytical framework and promotes CO depletion as a viable proxy of o$-$H$_2$D$^+$. We also explore the main limitations of the method by varying the physical size of the gas crossed by the cosmic rays (i.e. the path length). By employing a path length obtained from low-resolution observations, we recover values of the crir that are well below any existing theoretical and observational prediction. This discrepancy highlights the need for interferometric observations in order to reliably constrain the crir at parsec scales as well.

Advanced functional photochromic wearables with fast photo-responsivity, long color-retention, and multi-environmental stability

Smart photochromic wearables have demonstrated attractive prospects in many emerging fields. However, their lower functional performance limits their applications. Herein, we have fabricated a novel photochromic wearable fabric via covalent grafting and chemical isolation technique grafting WO3 nanoflowers onto cellulose. In the charming system, exceptional photochromic properties of WO3 serve as the color-changing material. Besides, incorporated potassium persulfate as a fast-fading reagent is capable of slow oxygen release upon heating. These combined components give the photochromic fabric a rapid response time of 2 s, a fading time of 5 min, and an unprecedented long color-retention (>7 days). Moreover, this photochromic fabric exhibits outstanding rewritability (100 cycles) and exceptional water resistance, maintaining superb photochromic performance even after undergoing standard washing (50 cycles). Moreover, the activation barriers to the photochromic mechanism for the minimum energy pathway were calculated, which provides a theoretical basis for hydrophobic design. The fabric not only imparts water and oil repellence and antifouling properties but also has chemical stability in multi-environments. Notably, the fabrication process is cost-effective, environmentally friendly, and amenable to large-scale production. Such fabrics hold tremendous promise in household products, public facilities and wearable healthcare technologies.