Open-air Conditions Research Articles

Estimation of Evaporation of Water from a Liquid Desiccant Solar Collector and Regenerator by Using Conservation of Mass and Energy Principles

Solar thermal energy-powered air conditioning technologies are receiving increased attention. Among the solar energy-driven cooling technologies, open type liquid desiccant air conditioning (AC) system is emerging as a promising technology, which has a solar driven desiccant solution regenerator. In this type of system, the evaporation of water and concentrating the desiccant or regenerator performance determines the cooling performance of the AC system, which necessitates its development and experimental performance testing under actual operating conditions. The setup is made of a black painted corrugated solar collector of area 0.8 m × 1.84 m covered with glass, and a liquid desiccant solution tank and distribution system over the absorber. Solar regeneration experiments on calcium chloride–water solution were carried out on the setup and a total of five sets of meteorological, collector and solution property data were collected through concentrating the desiccant from 32.9 initially to 51.3% in five days. The evaporation of water from the regenerator was analyzed using energy and desiccant mass conservation. For a typical day, the mass of water evaporated was estimated to be 3.10 and 3.16 kg over a day, as estimated by conservation of mass and energy principles from a 34.8 kg of calcium chloride solution with initial desiccant concentration of 43.6% stored in the tank.

Screening of Vitis vinifera cultivars from the Grapevine Germplasm Bank of Aragon for susceptibility to Botryosphaeria dieback fungi

Grapevine trunk diseases (GTDs) are taking the forefront of winegrowers’ concerns, as they cause considerable damage in vineyards not only quantitatively but also qualitatively. Furthermore, in the last three decades, an increasing incidence of the socioeconomic impact of these fungal pathologies has been observed. To date, no effective control strategies or curative treatments are available for these diseases that can replace the effectiveness offered by a series of chemical synthesis fungicides currently prohibited by European legislation. In this scenario, screening for less sensitive cultivars is regarded as a sustainable approach for GTDs management. In the study presented herein, the tolerance/susceptibility of 25 cultivars from the Grapevine Germplasm Bank of Aragon (Movera, Zaragoza, Spain) including commercial, local, or minority germplasm, was tested against two pathogens associated with Botryosphaeria dieback (viz. Neofusicoccum parvum and Diplodia seriata), which were inoculated in a detached cutting assay under open-air conditions. Based on lesion length development after eight months, significant differences were detected among the cultivars in the length of internal (vascular) necroses. In general terms, all cultivars were susceptible to fungal infection, but ‘Macabeo’ and one of the ‘Garnacha Tinta’ ecotypes under study (from Villanueva de Huerva, Zaragoza) would be the least susceptible white and red cultivars, respectively. On the other hand, ‘Monegrina’, ‘Grumel’, and ‘Torcijón’ would be among the least tolerant cultivars to fungal infection.

Preparation of Si@PVDF composite microspheres by electrostatic spraying for enhanced energetic characteristics

In this study, Si@PVDF composite microspheres are prepared by the electrostatic spraying method. The spheres are with average diameter of around 2 μm (when at ideal stoichiometry), within which Si nanopowder is uniformly distributed. The exothermic properties of samples are studied through simultaneous thermogravimetry and differential scanning calorimetry. Benefiting from the improved interfacial contact quality, Si@PVDF shows increased chemical reactivity in terms of reduced reaction onset temperature, peak temperature and apparent activation energy than those of physically mixed Si/PVDF counterpart. Si/PVDF cannot be ignited through Joule heating, either in the powder of pellet form, while self-sustained combustion propagation is observed for Si@PVDF pellets. The combustion behaviors of Si@PVDF pellets are systematically studied in open-air (where light signal is analyzed) and constant-volume (where pressure signal is analyzed) conditions. The results show that the combustion process is influenced by the equivalence ratio, porosity of the pellet and the accessibility of O2 gas in the environment. Overall, the encapsulation of Si nanopowder into PVDF microspheres using electrostatic spraying shortens the mass and heat transfer distance and thus realizes enhanced energetic characteristics.

A data-driven integrated framework for predictive probabilistic risk analytics of overhead contact lines based on dynamic Bayesian network

Due to completely working under open-air conditions without backup equipment, the overhead contact lines (OCLs) are suffering from external extreme weather conditions, except for the long-term dynamic vibrations of catenary-pantograph system. These risk factors are prone to cause failures of OCL components and power outages, which may further result in transportation interruptions, enormous economic losses, serious social impacts, and even catastrophic safety accidents. To comprehensively investigate the associated risks in OCLs, a data-driven integrated predictive probabilistic risk analytics framework based on dynamic Bayesian network is proposed to identify the significant risk factors and analyse the time-dependant failure patterns in dynamic risk propagation network of OCLs. After exploiting the weather-driven analytics for failure probability prediction, an integrated failure probability modelling for OCL components is developed, simultaneously incorporating internal, and weather-driven hazard factors of OCLs. A predictive risk metric is suggested based on the newly established risk propagation network of OCLs, which can account for weather hazards, system failures, financial costs, and social trust losses, in response to external weather conditions over time. Numerical studies conducted on the actual OCLs demonstrate that the proposed framework can dynamically model and evaluate risks of failure patterns that expose to OCLs.

Utilization possibilities of steel slag as backfill material in coastal structures

The aim of this study is to investigate the utilization possibilities of steel slags, basic oxygen furnace (BOF) and electric arc furnace (EAF) slags, as backfill material in coastal structures. Within the scope of the study, physical, mechanical and chemical properties of the steel slags were investigated and their potential to create environmental risks were evaluated. The results showed that soundness loss and filler content ratio were below the limit values for steel slags to be used as backfill material. It was determined that the density, porosity, water absorption and Los Angeles abrasion ratios of steel slags were generally higher than natural aggregates. In order to reach the California Bearing Ratio (CBR) limit (> 25%), the maximum particle size of the steel slag was reduced to 25 mm. In this particle size, CBR of the slag samples generally gave better results compared to the natural aggregate (38%), except for Kardemir and Asil samples. In addition, the concentration values of heavy metals (Cu, Cd, Cr, Pb, Ni, Zn, Hg and As) were below the limit values specified in the regulation. It is suggested that EAF slags should be aged for at least 6 months and BOF slags for at least 24 months in open air conditions before being used as backfill material in coastal structures after the maximum particle size is reduced to 25 mm.

Fully Methylammonium-Free Stable Formamidinium Lead Iodide Perovskite Solar Cells Processed under Humid Air Conditions.

Fabricating perovskite solar cells (PSCs) in ambient air condition is beneficial for lowering the processing cost and boosting the commercialization. Formamidinium lead iodide (FAPbI3) is an attractive candidate for efficient PSCs; however, it easily suffers from degradation and phase transition in the presence of ambient moisture. Methylammonium (MA) cation is commonly incorporated to stabilize FAPbI3, whereas the residual MA tends to deteriorate the thermal and operational stability. Herein, we report a MA-free strategy to fabricate high-quality α-FAPbI3 films and inverted PSCs under open air conditions with a relative humidity (RH) of 60 ± 10%. The incorporation of phenylethylammonium iodide (PEAI) effectively inhibits the decomposition and phase transition of FAPbI3 during its crystallization in humid air. Accordingly, phase-pure α-FAPbI3 perovskite films with significantly reduced δ-FAPbI3 and PbI2 content are successfully obtained. In addition, introducing PEAI strongly enhances the crystallinity of FAPbI3 perovskite films, thereby yielding enlarged grain sizes and reduced grain boundaries. Defects at the grain boundaries and surface are further passivated by PEAI addition, so that the trap state density is significantly decreased. As a result, the non-radiative recombination is effectively suppressed and the charge carrier transport is promoted. The inverted device optimized with a suitable PEAI concentration exhibits an enhanced power conversion efficiency (PCE) of 17.83%, which significantly surpasses the control device (12.29% PCE). Moreover, the PEAI optimized FAPbI3 PSCs demonstrate strongly improved long-term stability, with nearly 97% PCE maintained after 27-day storage under ambient conditions. This work provides a feasible way to fabricate PSCs in ambient air for promoting their wide range of applications.

Gold(III) Chloride-Mediated Transformation of Furfural to the trans-N,N-4,5-Diaminocyclopent-2-enones in the Presence of Anilines

We investigated the efficient approach of a series of trans-N,N-4,5-substituted-diaminocyclopent-2-enones (trans-DACPs) from furfural and anilines mediated by Gold(III) chloride (HAuCl4). The present protocol required a low amount of the catalysts, 1.5 mol%, open air conditions, the absence of any additives, and short reaction times. The desired trans-DACPs were isolated in good to high yields. The protocol was also applied to secondary amines, leading to the corresponding 4,5-diamino-cyclopent-2-enones in good yields. To the best of our knowledge, this is the first gold-mediated paradigm as an efficient catalyst for the formation of the cyclopentenones core-bearing C-N bonds under mild reaction conditions.

A high performance all-polymer symmetric faradaic deionization cell

Faradaic deionization (FDI) is an emerging and promising electrochemical technology for stable and efficient water desalination. Battery-type energy storage materials applied in FDI have demonstrated to achieve higher salt removal capacities than carbon-based conventional capacitive deionization (CDI) systems. However, most of the reported FDI systems are based on inorganic intercalation compounds that lack cost, safety and sustainability benefits, thereby curtailing the development of a feasible FDI cell. In this work, we introduce an all-polymer rocking chair practical FDI cell, with a symmetric system composed by a redox-active naphthalene-polyimide (named as PNDIE) buckypaper organic electrodes. First, electrochemical performance of PNDIE in 0.05 M NaCl under open-air conditions is evaluated in both three-electrode half- and symmetric FDI full-cell using typical lab-scale electrode dimensions (1.6 mgPNDIE; 0.78 cm2), revealing promising specific capacity (115 mAh g−1) and excellent cycle stability for full-cell experiments (77 % capacity retention over 1000 cycles). Then, all-polymer rocking chair FDI flow cell was constructed with practical PNDIE electrodes (92.2 mgPNDIE; 9.6 cm2) that delivered large desalination capacity (155.4 mg g−1 at 0.01 A g−1) and high salt-removal rate and productivity (3.42 mg g−1 min−1 at 0.04 A g−1 and 62 L h−1 m−2, respectively). In addition, long-term stability (23 days) experiments revealed salt adsorption capacity (SAC) retention values over 95% after 100 cycles. The overall electrochemical and deionization performances of the reported technology is far superior than the state-of-the-art CDI and FDI techniques, making it a competitive choice for robust and sustainable “water-energy” electrochemical applications.

An experimental and theoretical analysis of the dynamic response of solar drying in natural convection under rainy month of Maroua (Cameroon) of three tropical wood species

ABSTRACT This work aims to study and characterize the drying kinetics, the heat mass transfer coefficients, the densities, the thermal effusivities, the thermal diffusivities and Young’s modulus of three tropical kinds of wood: ayous (triplochiton scleroxylon), sapelli (Entandrophragma cylindricum) and iroko (Milicia excelsa). A comparison has been doing between drying using a low expensive solar dryer in natural convection and drying using open-air conditions. The novelty of this work is to use an experimental study during the rainiest period in the city of Maroua, one city in Cameroon with a hard climate. Densities are influenced by the origin of the samples in the plank and increase linearly with the moisture content. At 30&per; of humidity (d.b), average densities of sapelli, iroko, and ayous were equal to 1000, 760 and 600 kg/m3 respectively. Thermal effusivities and thermal diffusivities increase linearly with the moisture content. Thermal diffusivities of the three kinds of wood are very near (2 × 10−7 m2/s at 30&per; of humidity (d.b)) and thermal effusivities increase with the wood densities with values located from 560 to 620 J/(K.m2.s0.5) at 30&per; of humidity (d.b). The heat mass transfer coefficients are influenced by the night and day and vary from 1.5 × 10−8–1.8 × 10−7 m/s for the global mass transfer coefficients, and from 1.8–6.5 W/(m2K) for the heat transfer coefficients. According to the variations of the values of young’s modulus and the drying kinetics, drying in open-air conditions is more rapid and not recommended than one in the solar dryer. The equilibrium humidity of all samples is near 10&per; (d.b).

Comparison of adhesive joint strength of laser fabricated dimple textured Al–Mg alloy in different environment

Joining of aluminium alloys using adhesives has got tremendous applications in aviation, marines, and unmanned aerial vehicles. Surface preparation plays a crucial role in the adhesive joining of two surfaces. In this research work, the nanosecond fibre laser was used to create dimple-shaped textures on aluminium–Mg alloy (AA5754). Dimple-shaped textures were created under three different atmospheric conditions. Experiments were performed in open-air conditions, under static water conditions, and under flowing water conditions. Texture depths differed by varying the scanning speed of laser beam. Texture pitch was also varied at two different levels, that is 300 [Formula: see text]m and 400 [Formula: see text]m in both texturing directions. Two different scanning speeds of 2.5 and 5 mm/s of the laser beam were investigated. Surface contact angle of each sample was evaluated using a goniometer to measure surface hydrophobicity/ hydrophillicity. Surface roughness and dimensions of dimples were measured using a digital microscope. Scanning electron microscopes were used to evaluate the morphology of textured surfaces. An epoxy-based adhesive (partite) was uniformly spread over textured zones and samples for standard tensile tests were prepared as per ASTM. Shear lap tensile tests were carried out to evaluate the shear lap strength of each joint on a universal testing machine. Surfaces prepared in static water conditions and flowing water conditions resulted in completely different morphology compared to open-air processing. It was observed that dimple patterns fabricated under flowing water conditions had the highest bonding strength among all the three processing environments.

Eosin Y as a direct HAT photocatalyst for the synthesis of tetrahydrodipyrazolopyridines under white LED irradiation

A facile and efficient synthetic protocol has been developed for the synthesis of biologically privileged tetrahydrodipyrazolopyridines via visible light mediated one pot pseudo-six component reaction of ethyl acetoacetate, hydrazine hydrate, multifarious aldehydes and ammonium acetate (Knoevenagel condensation-Michael addition) by using metal-free, inexpensive eosin Y organic dye as a direct hydrogen atom transfer (HAT) catalyst at room temperature in open air condition. Mild condition, good yields, environment-friendly, high atom economy and good functional group tolerance of an extensive range of both electron-withdrawing and electron-donating groups are extra features of this approach. Additionally, this methodology is also appropriate for multi-gram scale, which enlighten the potentiality of using this reaction for industrial purposes.

A water-promoted catalytic hydrodecarboxylation of conjugated carboxylic acids under open air conditions at room temperature

The first example of organocatalyzed ionic hydrodecarboxylation of conjugated carboxylic acids has been developed under open air conditions at room temperature.

Molecular insights into the growth and time evolution of surface states of CsPbBr3 nanoparticles synthesized using a scalable room temperature approach

Room temperature ligand-assisted reprecipitation syntheses of CsPbBr3 nanoparticles (NPs) under open air conditions and with non-polar solvents have recently emerged as viable strategies for large-scale production of highly emissive NPs.

Performance and stability enhancement of perovskite photodetectors by additive and interface engineering using a dual-functional PPS zwitterion.

Hybrid organic-inorganic metal halide perovskites (HOIPs) have gained significant research interest due to their tunable optoelectronic properties and ease of fabrication. Enhancing the stability and efficiency of perovskite materials can be achieved through the passivation of defective surfaces and the improvement of interfacial properties. In this study, we introduce a zwitterionic compound, PPS (3-(1-pyridinio)-1-propanesulfonate), as a bifunctional material that serves as an additive and an interlayer. Incorporating PPS into the perovskite film effectively reduces both positively and negatively charged defects, leading to improved surface morphology and a reduction in undesired charge carrier recombination. Additionally, the formation of a PPS interlayer on SnO2 improves the SnO2/perovskite interfacial characteristics, thereby enhancing charge carrier extraction. As a result, the photodetector exhibits a low dark current of 6.05 × 10-11 A, an excellent responsivity of 5.93 A W-1, a detectivity of 1.51 × 1013 J, and an on/off ratio of 1.2 × 104 under open-air conditions. Moreover, the device demonstrates outstanding stability, retaining 80% of its original responsivity in an ambient environment. This work highlights the great potential of dual-functional materials for defect passivation in future optoelectronic devices, emphasizing the importance of surface modification and interface engineering for improved performance and stability.

Selecting molecular or surface centers in carbon dots-silica hybrids to tune the optical emission: A photo-physics study down to the atomistic level

In this work, we unveil the fluorescence features of citric acid and urea-based Carbon Dots (CDs) through a photo-physical characterization of nanoparticles synthesized, under solvent-free and open-air conditions, within silica-ordered mesoporous silica, as a potential host for solid-state emitting hybrids. Compared to CDs synthesized without silica matrices and dispersed in water, silica-CD hybrids display a broader emission in the green range whose contribution can be increased by UV and blue laser irradiation. The analysis of hybrids synthesized within different silica (MCM-48 and SBA-15) calls for an active role of the matrix in directing the synthesis toward the formation of CDs with a larger content of graphitic N and imidic groups at the expense of N-pyridinic molecules. As a result, CDs tuned in size and with a larger green emission are obtained in the hybrids and are retained once extracted from the silica matrix and dispersed in water. The kinetics of the photo-physics under UV and blue irradiation of hybrid samples show a photo-assisted formation process leading to a further increase of the relative contribution of the green emission, not observed in the water-dispersed reference samples, suggesting that the porous matrix is involved also in the photo-activated process. Finally, we carried out DFT and TD-DFT calculations on the interaction of silica with selected models of CD emitting centers, like surface functional groups (OH and COOH), dopants (graphitic N), and citric acid-based molecules. The combined experimental and theoretical results clearly indicate the presence of molecular species and surface centers both emitting in the blue and green spectral range, whose relative contribution is tuned by the interaction with the surrounding media.

Photovoltaic Mobile Charging System Design (Solar Pole) - in Gümüşhanevi Campus of Gümüşhane University

The decrease in fossil-based resources, the pollution of the environment and the threat of sustainability constantly increase the interest in renewable energy sources. Solar energy is one of the leading renewable energy sources due to its large capacity. Today, solar energy appears in many applications. In this study, a photovoltaic-based solar pole design has been realized and a prototype that can be applied almost anywhere in open-air conditions has been produced. The prototype produced was tested and installed at Gümüşhane University's Gümüşhanevi Campus. The prototype mobile phones produced have a fast charging feature with 5V-2A. In future studies, it is planned to provide the solar tracking feature to the photovoltaic (PV) panel in the system, and it is aimed to bring such systems to the campus in general.

Cobalt-Catalyzed Nitrogen Atom Insertion in Arylcycloalkenes.

Developing strategies enabling the modification of underlying molecular frameworks facilitates access to underexplored chemical spaces. Skeletal editing is an emerging technology for late-stage diversification of bioactive molecules. However, the current state of this knowledge remains undeveloped. This work describes a simple protocol that "inserts" a nitrogen atom into arylcycloalkenes to form the corresponding N-heterocycles. The use of an inexpensive cobalt catalyst under aqueous and open-air conditions makes this protocol very practical. Examples of late-stage modification of compounds of pharmaceutical interest and complex fused ring compounds further demonstrated the potentially broad applicability of this methodology.

Underwater laser texturing for enhanced adhesive joint bonding strength of Al-Mg alloy

In this research work, nanosecond pulsed fiber laser texturing was performed on Aluminum-Mg alloy (AA5754). Effect of laser texturing as a surface pre-treatment method in adhesive bonding process was investigated in details. Laser texturing was performed in under open air condition, under static water condition and under flowing water conditions. Grid shaped textures were fabricated on Al-Mg alloy work-pieces. The geometrical parameters of grid texturing were varied at two levels. Pitch of the lines were kept at 300 and 400 μm in both horizontal as well as vertical directions. Scanning speed of laser texturing process was also varied at two levels that is 2.5 and 5 mm/s. Total four experiments were conducted in each atmospheric conditions. Surface roughness and water contact angle of each surface was evaluated. Surfaces were also characterized using scanning electron microscope. Lap shear strength of each samples were evaluated using a universal tensile testing machine (UTM). Failed surfaces were analyzed to investigate the mode of failure. It was observed that the textures created in flowing water conditions resulted in cohesive mode of failure while samples fabricated in open air and in under static water conditions failed in adhesive and mixed mode respectively. Samples prepared in flowing water conditions resulted in higher lap shear strengths compared to static water, open air, and plain surfaces.

Effect of Shading on the Morphological, Physiological, and Biochemical Characteristics as Well as the Transcriptome of Matcha Green Tea.

High-quality tea leaves are required for matcha production. Shading is one of the key agronomic practices that can increase the quality of green tea. The objectives among matcha tea producers include increasing the ammonia and chlorophyll contents of tea buds, decreasing tea polyphenol contents, and enhancing tea aroma formation. In this study, Fuding white tea plants were cultivated under open-air conditions (control) as well as under 85% (S85) and 95% (S95) shade. The chlorophyll contents were highest for the S85 treatment, followed by the S95 and control treatments. Moreover, shading increased the theanine and caffeine contents, while decreasing the polyphenol (epicatechin and epigallocatechin) contents, thereby optimizing matcha tea flavors. A total of 2788 differentially expressed genes (DEGs) were identified, of which 1151 and 1637 were respectively upregulated and downregulated in response to shading. The GO and KEGG enrichment analyses indicated that most of the DEGs were associated with metabolic processes (e.g., MAPK signaling, plant-pathogen interactions, and phenylpropanoid biosynthesis). Therefore, shading may modulate tea plant metabolism, signaling, biosynthetic activities, and environment-related changes to gene transcription. The expression of amino acid permeases (APP) encoding genes was downregulated in tea plants. Thus, shading influences theanine biosynthesis and the AAP-mediated distribution of theanine in tea plants.

I2-DMSO-Promoted Direct Synthesis of Substituted Imidazoles from Styrenes and Benzylamines under Solvent-Free Conditions

AbstractA novel and efficient method has been developed for the direct synthesis of substituted imidazoles through the reaction of styrenes and benzylamines with the assistance of I2-DMSO concerted system. The reactions proceed efficiently under open air and solvent-free conditions to afford a wide variety of substituted imidazoles in good yields. A productive large-scale synthesis also has been performed to target highly substituted heterocyclic motifs. The present protocol offers metal- and solvent-free process, mild conditions, easily accessible reactants, and operational simplicity to achieve an assembly of substituted N-heterocyclic compounds.