Normal Atmospheric Conditions Research Articles

ß-Farnesene Exogenous Application as a Novel Damage Induction Model to Fast Explore the Effectiveness of Postharvest Strategies: The Case Study of the ‘Rocha’ Pear DOP

Since the prohibition of diphenylamine, replacement strategies have been needed for long-term disorder prevention, namely superficial scald (SC), in fruit. However, as this disorder only appears after months under cold storage, the assessment of effective strategies to prevent this disorder requires long periods. To tackle this challenge, we report in this paper a rapid and reliable system to induce symptoms, such as SC, based on storage under a β-farnesene-enriched atmosphere. Using this model, SC symptoms in ‘Rocha’ pear were induced after 15 d at 20 °C. As proof of concept, this model system allowed the study of the efficiency of antioxidant natural-based coatings on ‘Rocha’ pear quality maintenance. Pears treated with the coatings were submitted to 4 months of commercial storage under normal atmosphere conditions and the results were compared with those obtained using the induction model system. A PCA of chemical data allowed us to conclude that the model developed simulates the potential of certain strategies to prevent disorders.

Effect of Controlled Atmospheres and Environmental Conditions on the Physicochemical and Sensory Characteristics of Sweet Cherry Cultivar Satin

Sweet cherry is a highly appreciated seasonal fruit with a high content of bioactive compounds; however, this highly perishable fruit has a relatively short shelf-life period. Here, we evaluated the evolution of the physicochemical and sensory qualities of sweet cherries (Prunus avium (L.) cv. Satin) under different storage conditions, namely at a Farmers’ Organization (FO) and in a Research Centre (RC) under normal and four different conditions of controlled atmosphere for 49 days. Additional parameters were monitored, such as rotten fruit incidence and stem appearance. Temperature was the factor that most influenced the fruit quality changes over the study time. In fact, fruits stored at higher mean temperatures showed higher weight loss, higher variation in CIE-Lab colour parameters, higher firmness loss, and browner and more dehydrated stems and were less appealing to the consumer. Controlled atmosphere conditions showed a smaller decrease in CIE-Lab colour parameters and lower weight loss. The incidence of rotting was very low and was always equal or lower than 2% for all conditions. Thus, RC chamber conditions were able to sustain fruit quality parameters over 28 days under normal atmosphere conditions and 49 days under controlled atmosphere conditions.

Experimental Investigation on Mechanical Properties of A/GFRP, B/GFRP and AB/GFRP Polymer Composites

This study aims to reveal the consequence of thickness reinforcement on Fiber Laminates (Polyester Resin, Glass Fiber, Aluminum, and Bentonite) and to see if it can enhance the mechanical properties and resistance of laminates. Glass fiber reinforced polymer composites have recently been used in automotive, aerospace, and structural applications where they will be safe for the application s unique shape. Hand layup was used to fabricate three different combinations, including Aluminium /Glass fiber reinforced polyester composites (A/GFRP), Bentonite/Glass fiber reinforced polyester composites (B/GFRP), and Aluminium&Bentonie/Glass fiber reinforced polyester composites (AB/GFRP). Results revealed that AB/GFRP had better tensile strength, flexural strength, and hardness than GFRP and A/GFRP. Under normal atmospheric conditions and after exposure to boiling water, hybrid Aluminium&Bentonite and glass fiber-reinforced nanocomposites have improved mechanical properties than other hybrid composites. After exposure to temperature, the flexural strength, tensile strength and stiffness of AB/GFRP Composites are 40 % higher than A/GFRP and 17.44% higher than B/GFRP Composites.

Quality of fresh-cut apples as affected by dip wash treatments with organic acids and acidic electrolyzed water

The objective of this study was to investigate the effects of dipping in solutions of citric (2%), benzoic (0.2%), sorbic (0.2%) and ascorbic (0.5%) acids and in acidic electrolyzed water on the quality attributes and surface microbiota of fresh-cut apples, cvs ‘Florina’ and ‘Ionathan’, packaged in disposable plastic containers under normal atmospheric conditions during 14 days storage at 8 °C. The colour, firmness, total phenolic content, antioxidant activity and surface microbial load were determined weekly throughout storage. The colour results indicated that acidic electrolyzed water reduced browning while the ascorbic and citric acids were less effective in controlling the enzymatic browning of fresh-cut apples. After 14 days of refrigerated storage, the samples treated with 2% citric acid and acidic electrolyzed water maintained significantly higher firmness, total phenolic content and antioxidant activity than the other treated and control samples. The microbiological analysis revealed that organic acids successfully suppressed bacterial growth throughout the storage period as compared to the control samples. The sorbic and benzoic acids at 0.2% were also effective on yeasts but these dip treatments determined a higher darkening, yellowing and loss of firmness and of antioxidant activity during storage.

Multiple regression analysis on drilling performance of Al 2219 – SiCp metal matrix composite by Response surface Methodology (RSM) technique

In this work, Response Surface Methodology (RSM) based multiple performance analysis was used to investigate in detail about the influences of most dominating machining process parameters on responses like thrust force and surface roughness in the drilling of aluminium metal matrix composites developed through powder metallurgy process. Cylindrical specimens of Al 2219 aluminium alloy with silicon carbide particulates of average particle size 23, 37 and 67 µm as reinforcement are used in the experiment. Drilling test was carried out using poly crystalline diamond (PCD) coated solid tungsten carbide drill of diameter 5 mm at normal atmospheric conditions and different combinations of machining conditions. The RSM based multiple performance analysis was carried out to develop the input output relationships of the machining process parameters. The developed mathematical models were subjected to test their capability using analysis of variance (ANOVA). The main and interaction effect of the input variables on the responses was also investigated. The entire adequacy R2 has been more than 95%, which is within the desirable limit and indicate that the model is accurate and fit.

Self-combustion induced hierarchical nanoporous alloy transition toward high area property electrode for supercapacitor

The surfaces of nanoporous metals are easy to be oxidized under normal ambient condition. This usual attribute permits the exploration of metal-core oxide-shell structure that would be used for supercapacitors (SCs). However, the large-scale application of such electrodes is still limited by the intrinsically low ion diffusion coefficient, poor electronic conductivity and frustrating structural stability. Here we design a defect decorated hierarchical nanoporous CuMn2O4/Cu0.2Ni0.8O/CuxOy @ alloy electrode (HNP-TMO) by dealloying-coarsening-dealloying a sandwich-like NiCuMn/Ni/NiCuMn alloy and followed by self-combusting (2.1 mm s−1). The sandwiched Ni can synergy with unoxidized alloy to provide excellent mechanical stability and electronic conductivity, while the hierarchically porous structure with robust defects can ensure rapid electron/ion transportation. Benefiting from these merits, the HNP-TMO electrode with high mass loading of 7.8 mg cm−2 delivers an ultrahigh area capacity of 6.78 mAh cm−2 at 10 mA cm−2, good rate capability (maintaining 3.33 mAh cm−2 at ultra-high current density of 100 mA cm−2) and outstanding cycling performance with capacity retention of 92.7% after 12000 cycles. Full symmetric supercapacitor also demonstrates high energy and power density of 0.17 mWh cm−2 and 40.15 mW cm−2, respectively, indicating the promise for practical energy storage applications.

Enhancing sulfide mitigation via the sustainable supply of oxygen from air-nanobubbles in gravity sewers

Traditional air or oxygen injection is an effective and economical mitigation strategy for sulfide control in pressure sewers, but it is not suitable for gravity sewers due to the low solubility of oxygen in water under normal atmospheric conditions. Herein, an air-nanobubble (ANB) injection method was proposed for sulfide mitigation in gravity sewers, and its sulfide control efficiency was evaluated by long-term laboratory gravity sewer reactors. The results showed that an average inhibition rate of 45.36% for sulfide was obtained when ANBs were implemented, which was 3.75 times higher than that of the traditional air injection method, revealing the effectiveness and feasibility of the ANB injection method. As suggested by microbial community analysis of sewer biofilms, the relative abundance of sulfate-reducing bacteria (SRB) decreased 40.57% while that of sulfur oxidizing bacteria (SOB) increased 215.27% in the presence of ANBs, indicating that sulfide mitigation by ANB injection included both the inhibition of sulfide production and the oxidation of dissolved sulfide. The specific cost consumption of ANB injection was 1.7 $/kg-S, which was only 6.85% of that of traditional air injection (24.8 $/kg-S), suggesting that the sustainable supply of oxygen based on ANB injection is not only environmentally but also economically beneficial for sulfide mitigation. The findings of this study may provide an efficient sulfide mitigation strategy for the management of corrosion and malodour issues in the poorly ventilated gravity sewers.

Study on the electrowetting and beam current characteristics of externally wetted ionic liquid electrospray thruster

It is the theoretical basis to analyze the hydrodynamics mechanism of ionic liquid in an electrostatic field to ensure that the ionic liquid electrospray thruster possesses good wettability. Stable and continuous electrowetting emitters are closely related to thrust noise, resolution, and stability. Therefore, it is urgent to explore the law of ionic liquid electrowetting emitters in an electrostatic field to improve the performance of thrusters. The article proposes a new hybrid emitter structure, which consists of a V-blade emitter and a square capillary. It also carries out numerical simulation of emitter electrowetting under normal gravity and atmospheric conditions and emission experiments to explore the process of ionic liquid layer spreading on the external surface of the emitter. The dimensions of the emitter d1, d2, and θ and the physical properties of ionic liquids jointly determine the electrowetting velocity, the threshold of wetting voltage, and the liquid layer thickness. By analyzing the influence of various variables on electrowetting, a complete emitter electrowetting law of ionic liquid electrospray thrusters is summarized, which provides an important basis for the optimization of the emitter structure. Considering the scale of the emitter and bond ≈1, the meniscus in the electrostatic field is mainly affected by gravity, surface tension, viscous force, and electrophoretic force. Accordingly, it is worth noting that electrophoretic force is calculated by the Maxwell stress tensor method that treats ionic liquids as a dielectric to ensure the continuity of the meniscus. Although it can satisfy the electrowetting study at the macroscale, the interaction between anions and cations at the micro-scale is ignored. The numerical simulation results and the experimental results are correlated. It is proved that the method used in this article is accurate enough to simulate electrowetting before the liquid layer breaks up to form ion emission.

Effects of Electron Beam Irradiation on the Thermal Properties of Scrap Polytetrafluoroethylene

This study is focused on analyzing the effects of electron beam (EB) irradiation at high doses and normal atmospheric conditions on the thermal stability of scrap polytetrafluoroethylene (PTFE) solid to facilitate the recycling process of the material by grinding it into micro-powder additives for various applications. In this work, PTFE scrap with thickness not exceeding 1 mm was irradiated in doses between 0 - 1500 kGy using an electron beam accelerator machine (EBM) with a voltage energy of 3 MeV and current of 10 mA and grinded into powder by using a laboratory mill. The changes in morphology of the grinded powder, crystallinity and thermal properties of PTFE with increasing irradiation dose was studied by using scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The photomicrographs obtained from SEM showed that the particle size of the grinded micro-powder decreases with increasing irradiation dose with best results observed at 1500 kGy dose. DSC analysis showed that the crystallization temperature (Tc) and melting temperature (Tm) decreases with increasing irradiation doses as a result of lower molecular weight. XRD analysis of the irradiated PTFE indicated that the intensity of the peak had increased with increasing doses of irradiation due to the increase in crystallinity of the material. The distinctly shorter derivative thermogravimetric (DTG) peak height at 1500 kGy shows higher rate of mass loss at that dose due to the rapid loss of mechanical properties caused by degradation.

Enhanced voltammetric performance of sensors based on oxidized 2D layered black phosphorus

The exceptional properties of 2D layered black phosphorus (BP) make it a promising candidate for electrochemical sensing applications and, even though BP is considered unstable and tends to degrade by the presence of oxygen and moisture, its oxidation can be beneficial in some situations. In this work, we present an unequivocal demonstration that the exposition of BP-based working electrodes to normal ambient conditions can indeed be advantageous, leading to an enhancement of voltammetric sensing applications. This point was proved using a BP modified screen-printed carbon electrode (BP-SPCE) for the voltammetric determination of dopamine (DA) as a model target analyte. Oxidized BP-SPCE (up to 35% of PxOy at the surface) presented an enhanced analytical performance with a 5-fold and 2-fold increase in sensitivity, as compared to bare-SPCE and non-oxidized BP-SPCE stored in anhydrous atmosphere, respectively. Good detection limit, repeatability, reproducibility, stability, selectivity, and accuracy were also achieved. Overall, the results presented herein display the prominent possibilities of preparing and working with BP based-sensors in normal ambient settings and showcase their implementation under physiological conditions.

Synthesis and characterization of magnesium melting fluxes

Magnesium and its alloys are extremely susceptible to oxidation and fire due to their reactivity with oxygen. Therefore, special care should be taken while melting them. In this research, different types of fluxes were used to protect the molten magnesium from oxidation. These fluxes cover the molten magnesium surface and refine it. In this research, nine magnesium melting and refining fluxes were studied. Dow fluxes compositions were taken as a base to prepare five fluxes and another four fluxes were developed by varying the content of chlorides, fluorides, and oxide. The main purpose of this research is to increase the recovery of magnesium metal by melting in normal atmospheric conditions and develop a low-cost conventional melting practice. Decomposition behavior, mass change, and melting of these nine fluxes were studied by TG/DTA technique. After fusing, the surface morphology of these fluxes was studied by visual observation and scanning electron microscope. Magnesium was melted using these nine fluxes and for each flux, the weight loss of magnesium was calculated. From a thermal analysis study, it was confirmed that all the fluxes were fused before magnesium melting. Based on the flux layer which was generated during the melting and the weight loss analysis, flux 9 (250) was the best flux compared to other fluxes. The highest purity was obtained by using flux 2 with the highest tensile strength value.

Reduction of the carbon footprint of cargo vehicles with pneumatic recovery of braking energy

Reducing carbon dioxide emissions by passenger vehicles allows you to achieve the use of electric power plants and hybrid power plants made on the basis of thermal internal combustion engines and electric machines. However, the application of the above-mentioned approach for trucks is associated with significant difficulties due to the low specific capacity of the chemical current sources currently used. The recovery of braking energy of cargo vehicles in the pneumatic form is constrained by the need to achieve a high speed of switching on the pneumatic recuperator. In order to minimize the energy losses of the pneumatic recuperator during acceleration and steady-state. Without changing the design and reducing the reliability of the internal combustion engine, it is possible to supply air to its inlet at pressures not exceeding 350 kPa. When air is supplied to the internal combustion engine inlet at pressures of 200 and 300 kPa, it is possible to reduce specific carbon dioxide emissions by 16 and 37 % per unit of generated mechanical energy, respectively, compared to air supply under normal atmospheric conditions.

Mitochondrial superoxide dismutase overexpression and low oxygen conditioning hormesis improve the performance of irradiated sterile males

The Sterile Insect Technique (SIT) is a successful autocidal control method that uses ionizing radiation to sterilize insects. However, irradiation in normal atmospheric conditions can be damaging for males, because irradiation generates substantial biological oxidative stress that, combined with domestication and mass-rearing conditions, may reduce sterile male sexual competitiveness and quality. In this study, biological oxidative stress and antioxidant capacity were experimentally manipulated in Anastrepha suspensa using a combination of low-oxygen conditions and transgenic overexpression of mitochondrial superoxide dismutase (SOD2) to evaluate their role in the sexual behavior and quality of irradiated males. Our results showed that SOD2 overexpression enhances irradiated insect quality and improves male competitiveness in leks. However, the improvements in mating performance were modest, as normoxia-irradiated SOD2 males exhibited only a 22% improvement in mating success compared to normoxia-irradiated wild type males. Additionally, SOD2 overexpression did not synergistically improve the mating success of males irradiated in either hypoxia or severe hypoxia. Short-term hypoxic and severe-hypoxic conditioning hormesis, per se, increased antioxidant capacity and enhanced sexual competitiveness of irradiated males relative to non-irradiated males in leks. Our study provides valuable new information that antioxidant enzymes, particularly SOD2, have potential to improve the quality and lekking performance of sterile males used in SIT programs.

Effect of types of resin cements on the bond strength of fiber post under simulated dives

Background: Changes in barometric pressure conditions that occur during flying and diving under hyperbaric oxygen conditions were found to influence the retention of dental restorations. Aim: This experimental laboratory study aimed to evaluate the bond strength of glass fiber posts after being cemented with self-adhesive resin cement (RelyX™ Unicem, 3M ESPE) and self-etch adhesive resin cement (RelyX™ Ultimate, 3M ESPE) under normal atmospheric pressure and hyperbaric pressure cycles that simulate diving conditions. Methods: A total of 40 extracted, single-rooted mandibular premolars were treated endodontically and randomly divided into two groups according to the cements used for fiber post cementation. Each group was further randomly divided into two equal subgroups that were subjected to normal atmospheric pressure conditions and a simulated hyperbaric condition in a hyperbaric chamber. The pull-out bond strength of fiber posts was tested using a universal testing machine. Data were analyzed using one-way analysis of variance with the Tukey post-hoc test (p<0.05). Results: At normal atmospheric pressure the mean value of the pull-out bond strength of RelyX Ultimate cement was significantly higher than that of RelyX Unicem cement. At hyperbaric pressure condition no significant difference was found between the mean values of the pull-out bond strength of RelyX Ultimate and RelyX Unicem cement. Conclusion: Hyperbaric pressure cycles demonstrated improved pull-out bond strength of glass fiber posts in RelyX Unicem cement but did not have significant effect on pull-out bond strength in RelyX Ultimate cement. Both resin cements have similar pull-out bond strength of glass fibers post after simulated dives.

Egg Freshness Evaluation Using Transmission and Reflection of NIR Spectroscopy Coupled Multivariate Analysis.

This work presents a novel work for the detection of the freshness of eggs stored at room temperature and refrigerated conditions by the near-infrared (NIR) spectroscopy and multivariate models. The NIR spectroscopy of diffuse transmission and reflection modes was used to compare the quantitative and qualitative investigation of egg freshness. It was found that diffuse transmission is more conducive to the judgment of egg freshness. The linear discriminant analysis model (LDA) for pattern recognition based on the diffuse transmission measurement was employed to analyze egg freshness during storage. NIR diffuse transmission spectroscopy showed great potential for egg storage time discrimination in normal atmospheric conditions. The LDA model discrimination rated up to 91.4% in the prediction set, while only 25.6% of samples were correctly discriminated among eggs in refrigerated storage conditions. Furthermore, NIR spectra, combined with the synergy interval partial least squares (Si-PLS) model, showed excellent ability in egg physical index prediction under normal atmospheric conditions. The root means square error of prediction (RMSEP) values of Haugh unit, yolk index, and weight loss from predictive Si-PLS models were 4.25, 0.031, and 0.005432, respectively.

Oxidation of MBE-Grown ZnTe and ZnTe/Zn Nanowires and Their Structural Properties.

Results of comparative structural characterization of bare and Zn-covered ZnTe nanowires (NWs) before and after thermal oxidation at 300 °C are presented. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, and Raman scattering not only unambiguously confirm the conversion of the outer layer of the NWs into ZnO, but also demonstrate the influence of the oxidation process on the structure of the inner part of the NWs. Our study shows that the morphology of the resulting ZnO can be improved by the deposition of thin Zn shells on the bare ZnTe NWs prior to the oxidation. The oxidation of bare ZnTe NWs results in the formation of separated ZnO nanocrystals which decorate crystalline Te cores of the NWs. In the case of Zn-covered NWs, uniform ZnO shells are formed, however they are of a fine-crystalline structure or partially amorphous. Our study provides an important insight into the details of the oxidation processes of ZnTe nanostructures, which could be of importance for the preparation and performance of ZnTe based nano-devices operating under normal atmospheric conditions and at elevated temperatures.

Development of an Edible Coating from Okra Mucilage to Preserve the Crispiness in Soft Dough Biscuits Upon Storage

Baked food products are considered to be one of the most popular processed foods in the world. Among all the bakery products, biscuits are the most frequently consumed snack food item. There is a vast and diverse market for biscuits as a leader in ready-to-eat baked goods. Biscuits have long shelf life than other bakery products when stored under proper conditions. But immediately after exposure to the air by opening or damaging the package, biscuits absorb moisture from the air and reduce its crispiness of the biscuits. According to the market survey results, the highest number of respondents (53.7 %) suggested developing an edible coating for biscuits to prevent the loss of crispiness in biscuits upon storage. As well as 98.5 % of respondents prefer edible coatings developed using natural sources. Polysaccharide-based edible coatings maintain the physicochemical, microbiological & sensorial properties of the food. Therefore, okra mucilage was used as the main ingredient for edible coating preparation for biscuits. The coating was applied on biscuits with different coating methods, different baking stages and stored in different environmental conditions to identify the efficiency of the coating. According to the results, a coating applied before the baking stage displayed better moisture barrier properties than that of the coating applied after baking in controlled, semi-controlled, and normal atmospheric environmental conditions. It's responsible for the reduction of moisture absorption of biscuits upon storage

Effect of atmospheric conditions on the onset electric field of ZnO and Y2O3 ceramics flash sintering at room temperature

Flash sintering of zinc oxide (ZnO) ceramics can be induced at room temperature (25 °C) by electrical breakdown at high electric field strength. However, a strong discharge may degrade the sample. This study investigated the effects of atmospheric pressure and composition on the onset electric field for the flash sintering of ZnO. The experimental results show that flash sintering of ZnO under a low electric field at room temperature can be achieved by adjusting the atmospheric conditions. Compared with the onset electric field strength under normal atmospheric conditions, the value for flash sintering of ZnO at 20 kPa in a mixture of 20% air +80% argon (Ar) can be reduced by 82% to approximately 700 V/cm. This method also applies to yttrium oxide (Y2O3) for a low electric field in flash sintering at room temperature, and is the first report on flash sintering of Y2O3 at room temperature.

Photodegradation Behaviour of Nitrogen-Containing Graphene Derivatives Towards Pollutant Dyes and Real-TimeAssessment on Aquatic Weed

Discharge of dyes in the aquatic system is ubiquitous environmental chaos, and combating this particular anthropogenic issue with graphene-based materials via photodegradation process has been a radiant approach in recent times. In this work, 3-aminophenol produced nanosheets of N-graphene (NG) in the presence of urea in a single step at a relatively low temperature of ~ 120 – 125°C in contrast to nitrogen-containing graphene oxide (NGO) produced in the absence of urea. The V- shape of urea facilitated the formation of a poly-hexagonal array of rings and prevented the attack of oxygen at normal atmospheric conditions. During the comparison of the photodegradation ability of both NG and NGO against MG, MB, and MO, the degradation efficiency was found to be 92 - 99%. Further LC-MS/MS studies proved that NGO was capable of mineralizing the complex structures of the dyes via the demethylation route initially followed by asymmetric cleaving at neutral pH. The in-vitro real-time application of an aquatic weed (Lemna minor) was also compared against the 1:1:1 ratio of MG, MB, MO, and NGO-treated dye water. No substantial growth of Lemna minor was found in the case of using the dye mixture even up to the 20th day, whereas rapid growth of this aquatic weed was observed within 15 days in the case of NGO treated dye mixture.

Using Micro-Raman Spectroscopy to Investigate Chemical Composition, Mixing States, and Heterogeneous Reactions of Individual Atmospheric Particles.

Measuring the chemical composition of individual atmospheric aerosol particles can provide direct evidence of their heterogeneous reactions and mixing states in the atmosphere. In this study, micro-Raman spectroscopy was used to measure the chemical composition of 1200 individual atmospheric particles in 11 samples collected in Beijing air. (NH4)2SO4, NH4NO3, various minerals, carbonaceous species (soot and organics), and NaNO3 were identified in the measured particles according to their characteristic Raman peaks. These species represented the main components of aerosol particles. In individual particles, NH4NO3 and (NH4)2SO4 either existed separately or were internally mixed. Possible reaction pathways of CaCO3 particles in the atmosphere were proposed based on the results of this study and laboratory simulations on heterogeneous reactions in the literature. CaCO3 reacted with N- and S-containing (nitrogen- and sulfur-containing) acidic gases to produce Ca(NO3)2 and CaSO4. Ca(NO3)2 further reacted with S-containing acidic gases and oxidants to produce CaSO4. Of the soot-containing particles, 23% were internal mixtures of soot and inorganic material. Of the organics-containing particles, 57% were internal mixtures of organic and inorganic materials. Micro-Raman spectroscopy directly identified functional groups and molecules in individual atmospheric particles under normal ambient conditions, rendering it a powerful tool for measuring the chemical composition of individual atmospheric particles with a diameter of ≥1.0 μm.