scholarly journals Measurement report: The effect of aerosol chemical composition on light scattering due to the hygroscopic swelling effect

2021 ◽  
Author(s):  
Rongmin Ren ◽  
Zhanqing Li ◽  
Peng Yan ◽  
Yuying Wang ◽  
Hao Wu ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Mass Fraction ◽  
Mass Concentration ◽  
Negative Impact ◽  
Positive Impact ◽  
Parameterization Scheme ◽  
Ambient Aerosols ◽  
Inorganic Matter ◽  
Aerosol Hygroscopicity

Abstract. Liquid water in aerosol particles has a significant effect on optical properties, especially on light scattering, whose dependence on chemical composition is investigated here using measurements made in southern Beijing in 2019. The effect is measured by the enhancement of aerosol hygroscopic factor, f(RH = 85 %, 525 nm), which is found to be positively and negatively impacted by the proportions of inorganic and organic matters respectively. Black carbon is also negatively correlated. The positive impact is more robust when the inorganic matter mass fraction was smaller than 40 % (correlation coefficient, R = 0.93) which becomes weaker as the inorganic matter mass fraction gets larger (R = 0.48). A similar pattern was also found in the negative impact for organic matter mass fraction. Nitrate played a more significant role in aerosol hygroscopicity than sulfate in Beijing. However, the deliquescence point of ambient aerosols was at about RH = 80 % when the ratio of the sulfate mass concentration to the nitrate mass concentration of the aerosol was high (mostly higher than ~4). Two schemes to parameterize f(RH) were developed in accounting for the deliquescent and non-deliquescent effects. Using only one f(RH) parameterization scheme to fit all f(RH) processes would incur large errors. A piecewise parameterization scheme is proposed, which can better describe deliquescence and reduces uncertainties in simulating aerosol hygroscopicity.

scholarly journals Long-term aerosol optical hygroscopicity study at the ACTRIS SIRTA observatory: synergy between ceilometer and in-situ measurements

2019 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Gloria Titos ◽  
Juan Antonio Bravo-Aranda ◽  
Martial Haeffelin ◽  
Olivier Favez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Fraction ◽  
In Situ Measurements ◽  
Hygroscopic Growth ◽  
Ambient Aerosols ◽  
Inorganic Species ◽  
On Line ◽  
Remote Sensing Techniques ◽  
Aerosol Hygroscopicity

Abstract. An experimental setup to study aerosol hygroscopicity is proposed based on the time evolution of attenuated backscatter coefficients from a ceilometer co-located to an instrumented-tower equipped with meteorological sensors at different heights. This setup is used to analyse a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208º E, 48.713º N, 160 m above sea level). A strict criterion has been established to identify hygroscopic growth cases using ancillary information such as on-line chemical composition, resulting in eight hygroscopic growth cases from a total of 120 potential cases. For the eight cases, the hygroscopic growth-related properties such as the attenuated backscatter enhancement factor fβ (RH) and the hygroscopic growth coefficient γ are evaluated. This study evidence that the hygroscopicity parameter γ increases as the contribution of organic aerosols decreases. In this sense, organic mass fraction is anti-correlated with γ while it shows a positive correlation with the inorganic mass fraction. Among inorganic species, the higher correlation was found for NO3−. This is the first time that hygroscopic enhancement factors retrieved directly for ambient aerosols using remote sensing techniques are combined with on-line chemical composition in-situ measurements to evaluate the role of the different aerosol species on aerosol hygroscopicity.

scholarly journals Long-term aerosol optical hygroscopicity study at the ACTRIS SIRTA observatory: synergy between ceilometer and in situ measurements

2019 ◽  
Vol 19 (11) ◽  
pp. 7883-7896 ◽  
Author(s):  
Andrés Esteban Bedoya-Velásquez ◽  
Gloria Titos ◽  
Juan Antonio Bravo-Aranda ◽  
Martial Haeffelin ◽  
Olivier Favez ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Mass Fraction ◽  
In Situ Measurements ◽  
Hygroscopic Growth ◽  
Ambient Aerosols ◽  
Inorganic Species ◽  
Remote Sensing Techniques ◽  
First Time ◽  
Aerosol Hygroscopicity

Abstract. An experimental setup to study aerosol hygroscopicity is proposed based on the temporal evolution of attenuated backscatter coefficients from a ceilometer colocated with an instrumented tower equipped with meteorological sensors at different heights. This setup is used to analyze a 4.5-year database at the ACTRIS SIRTA observatory in Palaiseau (Paris, France, 2.208∘ E, 48.713∘ N; 160 m above sea level). A strict criterion-based procedure has been established to identify hygroscopic growth cases using ancillary information, such as online chemical composition, resulting in 8 hygroscopic growth cases from a total of 107 potential cases. For these eight cases, hygroscopic growth-related properties, such as the attenuated backscatter enhancement factor fβ (RH) and the hygroscopic growth coefficient γ, are evaluated. This study shows that the hygroscopicity parameter γ is negatively correlated with the aerosol organic mass fraction but shows a positive correlation with the aerosol inorganic mass fraction. Among inorganic species, nitrate exhibited the highest correlation. This is the first time that hygroscopic enhancement factors are directly retrieved under ambient aerosols using remote-sensing techniques, which are combined with online chemical composition in situ measurements to evaluate the role of the different aerosol species in aerosol hygroscopicity.

scholarly journals Aerosol hygroscopicity derived from size-segregated chemical composition and its parameterization in the North China Plain

2014 ◽  
Vol 14 (5) ◽  
pp. 2525-2539 ◽  
Author(s):  
H. J. Liu ◽  
C. S. Zhao ◽  
B. Nekat ◽  
N. Ma ◽  
A. Wiedensohler ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Ultrafine Particles ◽  
Mass Fraction ◽  
North China Plain ◽  
North China ◽  
The North ◽  
The North China Plain ◽  
Mass Fractions ◽  
Particulate Mass ◽  
Aerosol Hygroscopicity

Abstract. Hygroscopic growth of aerosol particles is of significant importance in quantifying the aerosol radiative effect in the atmosphere. In this study, hygroscopic properties of ambient particles are investigated based on particle chemical composition at a suburban site in the North China Plain during the HaChi campaign (Haze in China) in summer 2009. The size-segregated aerosol particulate mass concentration as well as the particle components such as inorganic ions, organic carbon and water-soluble organic carbon (WSOC) are identified from aerosol particle samples collected with a ten-stage impactor. An iterative algorithm is developed to evaluate the hygroscopicity parameter κ from the measured chemical composition of particles. During the HaChi summer campaign, almost half of the mass concentration of particles between 150 nm and 1 μm is contributed by inorganic species. Organic matter (OM) is abundant in ultrafine particles, and 77% of the particulate mass with diameter (Dp) of around 30 nm is composed of OM. A large fraction of coarse particle mass is undetermined and is assumed to be insoluble mineral dust and liquid water. The campaign's average size distribution of κ values shows three distinct modes: a less hygroscopic mode (Dp < 150 nm) with κ slightly above 0.2, a highly hygroscopic mode (150 nm < Dp < 1 μm) with κ greater than 0.3 and a nearly hydrophobic mode (Dp > 1 μm) with κ of about 0.1. The peak of the κ curve appears around 450 nm with a maximum value of 0.35. The derived κ values are consistent with results measured with a high humidity tandem differential mobility analyzer within the size range of 50–250 nm. Inorganics are the predominant species contributing to particle hygroscopicity, especially for particles between 150 nm and 1 μm. For example, NH4NO3, H2SO4, NH4HSO4 and (NH4)2SO4 account for nearly 90% of κ for particles of around 900 nm. For ultrafine particles, WSOC plays a critical role in particle hygroscopicity due to the predominant mass fraction of OM in ultrafine particles. WSOC for particles of around 30 nm contribute 52% of κ. Aerosol hygroscopicity is related to synoptic transport patterns. When southerly wind dominates, particles are more hygroscopic; when northerly wind dominates, particles are less hygroscopic. Aerosol hygroscopicity also has a diurnal variation, which can be explained by the diurnal evolution of planetary boundary layer, photochemical aging processes during daytime and enhanced black carbon emission at night. κ is highly correlated with mass fractions of SO42−, NO3− and NH4+ for all sampled particles as well as with the mass fraction of WSOC for particles of less than 100 nm. A parameterization scheme for κ is developed using mass fractions of SO42−, NO3−, NH4+ and WSOC due to their high correlations with κ, and κ calculated from the parameterization agrees well with κ derived from the particle's chemical composition. Further analysis shows that the parameterization scheme is applicable to other aerosol studies in China.

TURN-OVER GURU PADA MADRASAH ALIYAH NAHDLATUL ULAMA

1970 ◽  
Vol 13 (1) ◽  
Author(s):  
Mochamad Iskarim
Keyword(s):  
Data Collection ◽  
Negative Impact ◽  
Positive Impact ◽  
New Teacher ◽  
Qualitative Approach ◽  
Depth Interview ◽  
Nahdlatul Ulama ◽  
Turn Over ◽  
Interview Questionnaire ◽  
Collection Methods

Penelitian ini dimaksudkan untuk mengetahui dampak positif dan negatif dari adanya pergantian (turn-over) guru di Madrasah Aliyah Nahdlatul Ulama Banyuputih kabupaten Batang. Penelitian inimenggunakan pendekatan kualitatif deskriptif analitis dengan metode pengumpulan data berupa wawancara mendalam, angket, dan dokumentasi. Hasil penelitian menunjukkan adanya turn-over yang tinggi pada guru atau pendidik di madrasah tersebut; keuntungan yang bersifat positif justru didapatkan ketika adanya turn-over guru dibandingkan dampak negatifnya; dan kehadiran guru baru menjadi hal yang sangat disukai oleh siswa dalam hal kreativitas, inovasi pembelajaran, motivasi, dan lain sebagainya.The aims of this research were to know the positive and negative impact of teacher turn over at Madrasah Aliyah Nahdlatul Ulama Banyuputih Kabupaten Batang. This research was use analytical descriptive qualitative approach with depth interview, questionnaire and documentation as data collection methods. The results of this research shows that the positive impact occur more than the negative impact when there was teacher turn over; and the presence of a new teacher become student’s favourite on creativity, learning innovation, and motivation aspects.

Preparation of graft copolymers by the reaction of polymeric acyl chlorides with monohydroxy-terminated polymers: An introductory study

1988 ◽  
Vol 53 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
Jitka Horská ◽  
Jaroslav Stejskal ◽  
Pavel Kratochvíl ◽  
Aubrey D. Jenkins ◽  
Eugenia Tsartolia ◽  
...  
Keyword(s):  
Light Scattering ◽  
Chemical Composition ◽  
Statistical Model ◽  
Graft Copolymers ◽  
Coupling Reaction ◽  
Molecular Characteristics ◽  
Gel Formation ◽  
Acyl Chlorides ◽  
Molecular Weights

An attempt was made to prepare well-defined graft copolymers by the coupling reaction between acyl chloride groups located along the backbone chain and monohydroxy-terminated grafts prepared separately. The molecular weights and the parameters of heterogeneity in chemical composition of the products were determined by light scattering and osmometry. The determination of molecular characteristics revealed that the degree of grafting was low. The results therefore could not be confronted with a statistical model at this stage. The problems encountered in the synthesis, e.g., gel formation, and the data relating to the soluble products are discussed.

Accidental Sustainability

2017 ◽  
Author(s):  
Geoffrey Jones
Keyword(s):  
Large Scale ◽  
Negative Impact ◽  
Positive Impact ◽  
Organic Food ◽  
The United States ◽  
Air Travel ◽  
Business Leaders ◽  
Natural Beauty ◽  
And Diffusion ◽  
Whole Foods

This chapter examines the scaling and diffusion of green entrepreneurship between 1980 and the present. It explores how entrepreneurs and business leaders promoted the idea that business and sustainability were compatible. It then examines the rapid growth of organic foods, natural beauty, ecological architecture, and eco-tourism. Green firms sometimes grew to a large scale, such as the retailer Whole Foods Market in the United States. The chapter explores how greater mainstreaming of these businesses resulted in a new set of challenges arising from scaling. Organic food was now transported across large distances causing a negative impact on carbon emissions. More eco-tourism resulted in more air travel and bigger airports. In other industries scaling had a more positive impact. Towns were major polluters, so more ecological buildings had a positive impact.

scholarly journals Socioeconomic Conditions and Landowners’ Perception Affect the Intention to Restore Polylepis Forests in the Central Andes of Peru

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 118
Author(s):  
Lunel Joseph ◽  
Raúl Marino Yaranga Cano ◽  
Marco Arizapana-Almonacid ◽  
Marcela Venelli Pyles ◽  
Flávia Freire de Siqueira ◽  
...  
Keyword(s):  
Rural Communities ◽  
Mixed Model ◽  
Linear Mixed Model ◽  
Negative Impact ◽  
Positive Impact ◽  
Central Andes ◽  
Socioeconomic Conditions ◽  
Native Flora ◽  
The Family ◽  
Andes Region

Research Highlights: Families more dependent on crops as the main source of income of properties have a greater intention of restoring Polylepis forest areas. However, this intention reduces with the increase of family dependence on subsistence products supplied by Polylepis forests. Properties where the chances of restoration of Polylepis forests are greater are those where the educational and technical level is better. Objectives: We aimed to comprehend which socioeconomic factors of rural properties and families’ perception were determinant for the intention to restore Polylepis forests in the Central Andes region of Peru. Material and Methods: We collected data through visits and the application of questionnaires. We selected 13 rural communities in the Tulumayo River Basin. We randomly sampled 10 to 20 families in each community, depending on its size, totaling 200 families. We used generalized linear mixed model (GLMM) to test which variables affect the intention to restore the forest. Results: When crops are the main source of income in the property, the families have more intention to restore Polylepis areas, on the other hand, when Polylepis forests are an important source of products for the family subsistence, the intention to restore forests reduces, indicating that higher technological status has a positive impact on restoration. The perception that Polylepis forests are important for the existence of water sources had a positive impact on the families’ intention to restore the areas. However, the perception that Polylepis forests are important for native flora persistence had a negative impact on the intention to restore their areas. Conclusions: Our results showed that investment in improving the productivity of the properties and in the education of their landowners should increase the success of eventual programs for restoration of Polylepis forests.

043 Sleep Restriction Affects Memory in Healthy Adults: Preliminary Findings

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A18-A19
Author(s):  
Molly Zimmerman ◽  
Christiane Hale ◽  
Adam Brickman ◽  
Lok-Kin Yeung ◽  
Justin Cochran ◽  
...  
Keyword(s):  
Working Memory ◽  
Negative Impact ◽  
Positive Impact ◽  
Healthy Adults ◽  
Task Demands ◽  
Sleep Restriction ◽  
Neuropsychological Function ◽  
Wake Time ◽  
Sleep Condition ◽  
The Impact

Abstract Introduction Sleep loss has a range of detrimental effects on cognitive ability. However, few studies have examined the impact of sleep restriction on neuropsychological function using an experimental design. The goal of this study was to examine the extent to which maintained insufficient sleep affects cognition in healthy adults compared to habitual adequate sleep. Methods This study used a randomized, crossover, outpatient sleep restriction design. Adults who regularly slept at least 7 h/night, verified by 2 weeks of screening with actigraphy, completed 2 phases of 6 weeks each: habitual sleep (&gt;7 h of sleep/night) or sleep restriction (habitual sleep minus 1.5 h) separated by a 6-week washout period. During the sleep restriction phase, participants were asked to delay their bedtime by 1.5 hours/night while maintaining their habitual wake time. Neuropsychological function was evaluated with the NIH Toolbox Cognition Battery at baseline (week 0) and endpoint (week 6) of each intervention phase. The NIH Toolbox evaluates a range of cognitive abilities, including attention, executive functioning, and working memory. General linear models with post hoc paired t-tests were used to assess demographically-adjusted test scores prior to and following each sleep condition. Results At the time of analyses, 16 participants were enrolled (age 34.5□14.5 years, 9 women), 10 of whom had completed study procedures. An interaction between sleep condition and testing session revealed that individuals performed worse on List Sorting, a working memory test, after sleep restriction but improved slightly after habitual sleep (p&lt;0.001). While not statistically reliable, the pattern of test results was similar on the other tests of processing speed, executive function, and attention. Conclusion In these preliminary results from this randomized experimental study, we demonstrated that sleep restriction has a negative impact while stable habitual adequate sleep has a positive impact on working memory, or the ability to temporarily hold information in mind while executing task demands. This finding contributes to our understanding of the complex interplay between different aspects of sleep quality (i.e., both sleep restriction as well as the maintenance of stable sleep patterns) on cognition and underscores the importance of routine sleep screening as part of medical evaluations. Support (if any):

scholarly journals Exploring the Relationship between Communication and Success of Construction Projects: The Mediating Role of Conflict

2021 ◽  
Vol 13 (8) ◽  
pp. 4513
Author(s):  
Summaira Malik ◽  
Muhammad Taqi ◽  
José Moleiro Martins ◽  
Mário Nuno Mata ◽  
João Manuel Pereira ◽  
...  
Keyword(s):  
Project Success ◽  
Negative Impact ◽  
Positive Impact ◽  
Construction Project ◽  
Project Team ◽  
Relationship Conflict ◽  
Team Members ◽  
Mediating Role ◽  
The Impact

The success of a construction project is a widely discussed topic, even today, and there exists a difference of opinion. The impact of communication and conflict on project success is an important, but least addressed, issue in literature, especially in the case of underdeveloped countries. Miscommunication and conflict not only hinder the success of a project but also may lead to conflicts. The focus of this paper was to examine the impact of communication on project success with the mediating role of conflict. By using SPSS, demographics, descriptive statistics and correlation were determined. Smart PLS version 3.0 was used for confirmatory factor analysis (CFA), internal accuracy and validity estimates, hypothesis checking and mediation testing. The results showed that formal communication has a negative impact on the success of a construction project, resulting in conflicts among project team members, whereas informal communication and communication willingness have a positive impact on project success because people tend to know each other, and trust is developed. Task, process and relationship conflicts were used as mediating variables. It was found that task conflict effects the relations positively because project team members suggest different ways to do a certain task, and, hence, project success is achieved. On the contrary, process conflict and relationship conflict have a negative impact on communication and project success. Both of these conflicts lead to miscommunication, and project success is compromised. Hence, it is the responsibility of the project manager to enhance communication among project team members and to reduce the detrimental effects of process and relationship conflict on project success.

scholarly journals The Urbanisation Impacts on the Policy Effects of the Carbon Tax in China

2021 ◽  
Vol 13 (12) ◽  
pp. 6749
Author(s):  
Shuyang Chen
Keyword(s):  
Energy Consumption ◽  
Carbon Emissions ◽  
Computable General Equilibrium ◽  
Carbon Tax ◽  
Negative Impact ◽  
Positive Impact ◽  
Evaluation Framework ◽  
Socioeconomic Impacts ◽  
Policy Effects ◽  
Distributed Lag

In the literature, very few studies have focused on how urbanisation will influence the policy effects of a climate policy even though urbanisation does have profound socioeconomic impacts. This paper has explored the interrelations among the urbanisation, carbon emissions, GDP, and energy consumption in China using the autoregressive distributed lag (ARDL) model. Then, the unit urbanisation impacts are inputted into the policy evaluation framework of the Computable General Equilibrium (CGE) model in 2015–2030. The results show that the urbanisation had a positive impact on the GDP but a negative impact on the carbon emissions in 1980–2014. These impacts were statistically significant, but its impact on the energy consumption was not statistically significant. In 2015–2030, the urbanisation will have negative impacts on the carbon emissions and intensity. It will decrease the GDP and the household welfare under the carbon tax. The urbanisation will increase the average social cost of carbon (ASCC). Hence, the urbanisation will reinforce the policy effects of the carbon tax on the emissions and welfare.

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