haze formation
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2022 ◽  
Vol 13 (1) ◽  
Author(s):  
Siteng Fan ◽  
Peter Gao ◽  
Xi Zhang ◽  
Danica J. Adams ◽  
Nicholas W. Kutsop ◽  
...  

AbstractPluto, Titan, and Triton make up a unique class of solar system bodies, with icy surfaces and chemically reducing atmospheres rich in organic photochemistry and haze formation. Hazes play important roles in these atmospheres, with physical and chemical processes highly dependent on particle sizes, but the haze size distribution in reducing atmospheres is currently poorly understood. Here we report observational evidence that Pluto’s haze particles are bimodally distributed, which successfully reproduces the full phase scattering observations from New Horizons. Combined with previous simulations of Titan’s haze, this result suggests that haze particles in reducing atmospheres undergo rapid shape change near pressure levels ~0.5 Pa and favors a photochemical rather than a dynamical origin for the formation of Titan’s detached haze. It also demonstrates that both oxidizing and reducing atmospheres can produce multi-modal hazes, and encourages reanalysis of observations of hazes on Titan and Triton.


Author(s):  
Sarah E. Moran ◽  
Sarah M. Hörst ◽  
Chao He ◽  
Michael J. Radke ◽  
Joshua A. Sebree ◽  
...  

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Yuanyuan Meng ◽  
Wanlong Sun

China’s rapid urbanisation and industrialisation have led to frequent haze in China in recent years. Although many measures to control haze have been implemented, no significant improvement has been observed, and haze still exists. In this study, we used wavelet transform to investigate the changes in PM2.5 on the time scale, the relationship amongst meteorological factors, and the causes and changes in haze formation and take measures to prevent haze. Results indicated the following: (1) The peak of PM2.5 changes in winter in the past three years primarily occurred in the range from 11:00 to 13:00 and 20:00 to 22:00. (2) Multiple cycles of daily average PM2.5 concentrations existed in 3–5 d, 6–14 d, 6–21 d, and 16–27 d, with a significant oscillation in 6–14 d and stable cycle characteristics. (3) The meteorological factors promoted the formation of haze to a certain extent. When haze occurred, the near-surface wind speed was only 1 m/s, which was not conducive to the spread of pollutants. (4) The formation of haze was affected by the interaction of various factors; the photochemical reactions of NO2 and O3 also exacerbated the formation of pollutants. This study provided a clear direction for the prevention and prediction of haze. Furthermore, the government must take relevant measures to reduce pollutant emissions and ensure the air quality of cities in winter.


Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3114
Author(s):  
Yin Wang ◽  
Lingzhen Ye

Beer is one of the oldest and most widely consumed alcoholic beverages. Haze formation in beer is a serious quality problem, as it largely shortens the shelf life and flavor of beer. This paper reviews the factors affecting haze formation and strategies for reducing haze. Haze formation is mainly associated with specific chemical components in malt barley grains, such as proteins. The main factor causing haze formation is a cross-linking of haze active (HA) proteins and HA polyphenols. Many HA proteins and their editing genes or loci have been identified by proteomics and quantitative trait locus (QTL) analysis, respectively. Although some technical approaches have been available for reducing haze formation in beer, including silica and polyvinylpolypyrrolidone (PVPP) adsorbent treatments, the cost of beer production will increase and some flavor will be lost due to reduced relevant polyphenols and proteins. Therefore, breeding the malt barley cultivar with lower HA protein and/or HA polyphenols is the most efficient approach for controlling haze formation. Owing to the completion of barley whole genome sequencing and the rapid development of modern molecular breeding technology, several candidate genes controlling haze formation have been identified, providing a new solution for reducing beer haze.


Author(s):  
Wendell Albuquerque ◽  
Leif Seidel ◽  
Holger Zorn ◽  
Frank Will ◽  
Martin Gand
Keyword(s):  

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Anita Csorba ◽  
Kinga Kránitz ◽  
Péter Dormán ◽  
Andrea Popper-Sachetti ◽  
Huba Kiss ◽  
...  

Abstract Background Our aim was to determine associations of pachymetry, keratometry, and their changes with haze formation and corneal flattening after collagen cross-linking, and to analyse the relationship between postoperative haze and visual outcome. Methods Retrospective analysis was performed on 47 eyes of 47 patients with keratoconus using the Pentacam HR Scheimpflug camera before and 1, 3, 6 and 12 months after cross-linking. Corneal backscattered light values in grey scale unit were recorded in the anterior, center and posterior corneal layers and in four concentric rings. Surface area- and thickness-corrected grey scale unit values were assessed with an additional calculation. Friedman test with post hoc Wilcoxon signed-rank test was used to analyse changes in visual acuity, pachymetry, keratometry and densitometry. Spearman’s rank correlation test was used to detect correlations of haze formation and corneal flattening with pachymetry, keratometry and their postoperative change. Generalized estimating equations analysis was used to investigate the influence of densitometry values on postoperative visual acuity after controlling for the effect of preoperative keratometry. Results One year after treatment, significant flattening was observed in maximum and mean keratometry readings (p < 0.001). Significantly increased densitometry values were observed in three central rings compared to baseline (post hoc p < 0.0125). According to receiver operating characteristic curve, densitometry value of the anterior layer of 0–2 mm ring was the most characteristic parameter of densitometry changes after cross-linking (area under the curve = 0.936). Changes in haze significantly correlated with preoperative maximum keratometry (R = 0.303, p = 0.038) and with the changes in maximum keratometry (R = -0.412, p = 0.004). Changes in maximum keratometry correlated with preoperative maximum keratometry (R = -0.302, p = 0.038). Postoperative haze had a significant impact on uncorrected and best corrected distance visual acuity (β coefficient = 0.006, p = 0.041 and β coefficient = 0.003, p = 0.039, respectively). Conclusions Our findings indicate that in more advanced keratoconus more significant corneal flattening effect parallel with haze formation can be observed after cross-linking. Despite significant reduction of keratometry, postoperative corneal haze may limit final visual acuity.


2021 ◽  
Vol 14 (8) ◽  
pp. 1225-1230
Author(s):  
Mehrdad Mohammadpour ◽  
◽  
Delaram Shakoor ◽  

AIM: To compare outcomes of applying preservative free artificial tears (PFAT) with and without hyaluronic acid (HA) in early postoperative course following photorefractive keratectomy (PRK). METHODS: In this triple-blinded randomized clinical trial, PRK procedure was performed on both eyes of 230 patients. Following PRK, patients were divided into three groups: the HA+ group, 44 patients PFAT containing HA; the HA- group, 71 patients PFAT without HA were administered 5 times per day (every 4h); the third group, 115 patients received no PFAT before lens removal. On the 1st and 4th postoperative day, Visual Analogue Score (VAS) was utilized to evaluate patient’s level of pain. Participants were asked to complete a questionnaire about the severity of eye discomfort ranked from 0 to 10 (0=no complaint; 10=most severe complaint experienced). RESULTS: In eyes receiving PFAT with or without HA (Drop group), mean scores for epiphora, foreign body sensation, and blurred vision on the 1st postoperative day were statistically lower (P<0.05). Filamentous keratitis (FK) was detected in 11 (4.7%) eyes, and recurrent corneal erosion (RCE) was observed in 5 (2.1%) eyes. In the control group, FK was noted in 16 (6.9%) eyes while 13 (5.6%) eyes had RCE and 5 (2.1%) eyes had corneal haze. The rate of complications was statistically lower in Drop group (P=0.009). However, the aforementioned scores were not statically different between HA+ and HA- group one and two (P=0.29). CONCLUSION: Following PRK, applying PFAT with and without HA yields faster visual recovery, decreases postoperative ocular discomfort and haze formation; however there is no additive effect for HA.


Beverages ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 57
Author(s):  
Diana Gago ◽  
Ricardo Chagas ◽  
Luísa M. Ferreira

Wine clarity is a critical aspect in the commercialization of white wines. The formation of wine haze can be attributed to the aggregation and precipitation of heat-unstable wine proteins. Bentonite fining is the commonly used method in winemaking for protein removal, but it is responsible for loss of wine volume and quality. Dicarboxymethyl cellulose (DCMC) was developed as a potential alternative to bentonite. Water-insoluble DCMC was prepared via catalyzed heterogeneous etherification using sodium chloromalonate and potassium iodide. White wine fining trials were benchmarked with different dosages of DCMC against a bentonite. A high-performance liquid chromatography method was optimized for protein quantification. The samples underwent heat stability tests to evaluate wine turbidity before and after fining. Results show that DCMC successfully reduced the wine protein content and turbidity. DCMC produced heat-stable wines with dosages higher than 0.25 g/L. The innovative application of DCMC in the wine sector shows potential due to its ability to stabilize white wines while overcoming problems associated with bentonite, such as lees production and loss of wine, contributing to a more sustainable process.


2021 ◽  
Author(s):  
Anne Wellbrock ◽  
Andrew Coates ◽  
Geraint Jones ◽  
Richard Haythornthwaite ◽  
Oleg Shebanits ◽  
...  

&lt;p&gt;The discovery of heavy organic anions by in situ measurements using Cassini&amp;#8217;s CAPS Electron Spectrometer (ELS) in Titan&amp;#8217;s ionosphere was an unexpected result of the Cassini mission (Coates et al, 2007, Waite et al, 2007); a complete reconsideration of chemical processes in this enigmatic atmosphere was necessary as a result. These negative ions can be associated with complex hydrocarbon and nitrile processes which are linked to haze formation at lower altitudes. Cassini&amp;#8217;s CAPS ELS observed negative ions during Titan encounters at altitudes below 1400 km. The ions can reach masses over 13,000 amu/q (Coates et al., 2009), while recurring peaks in the mass spectra can be used to identify different mass groups as reported by Coates et al. (2007) and Wellbrock et al. (2013, 2019). Studying density and mass trends of these groups helps to identify controlling factors of the production and destruction mechanisms, and ultimately to improve our understanding of how organic macromolecules can be produced by naturally occurring abiotic processes. In this study we examine the effects different solar zenith angle conditions might have on both the light and heavy negative ion mass groups, and consider the role of processes such as photodetachment and dissociative electron attachment. We also compare the negative ion data with RPWS electron measurements and discuss the possible implications associated with the above processes.&lt;/p&gt;


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