The Role of Binary and Ion Nucleation of Sulfuric Acid and Water Vapor in the Dynamics of Sulfate Aerosol Formation in the Atmosphere

2021 ◽  
pp. 53-60
Author(s):  
A. E. Aloyan ◽  
◽  
A. N. Yermakov ◽  
V. O. Arutyunyan ◽  
◽  
...  
Keyword(s):  
Water Vapor ◽  
Sulfuric Acid ◽  
Three Dimensional ◽  
Ionization Rate ◽  
Sulfate Aerosol ◽  
Aerosol Formation ◽  
Three Dimensional Model ◽  
Aerosol Composition ◽  
Transport And Transformation

The results of one-dimensional calculations of the height profiles of nucleated sulfate aerosol particles for the northern mid-latitudes and tropics in winter are presented. Numerical calculations were performed using a three-dimensional model of the transport and transformation of multicompo- nent gas and aerosol substances in the atmosphere, incorporating photochemistry, nucleation involving neutral molecules and ions, as well as condensation/evaporation and coagulation. It is found that the resulting dynamics of the formation of aerosol particle nuclei is not a simple sum of ion and binary (water vapor/sulfuric acid) nucleation rates. This dynamics is determined by the ratio of critical radii of nucleated particles due to binary and ion nucleation of these substances (rcr_bin and rcr_ion) depending on temperature, relative humidity, and ionization rate. This should be taken into account in modeling the gas and aerosol composition of the atmosphere and comparing calculated and observed data.

scholarly journals The role of a mid-air collision in drifting snow

2018 ◽  
Author(s):  
Shuming Jia ◽  
Zhengshi Wang ◽  
Shumin Li
Keyword(s):  
Friction Velocity ◽  
Global Climate ◽  
Three Dimensional ◽  
Particle Collision ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Two Phase ◽  
Drifting Snow ◽  
Collision Mechanism

Abstract. Drifting snow, a common two-phase flow movement in high and cold areas, contributes greatly to the mass and energy balance of glacier and ice sheets and further affects the global climate system. Mid-air collisions occur frequently in high-concentration snow flows; however, this mechanism is rarely considered in current models of drifting snow. In this work, a three-dimensional model of drifting snow with consideration of inter-particle collisions is established; this model enables the investigation of the role of a mid-air collision mechanism in openly drifting snow. It is found that the particle collision frequency increases with the particle concentration and friction velocity, and the blown snow with a mid-air collision effect produces more realistic transport fluxes since inter-particle collision can enhance the particle activity under the same condition. However, the snow saltation mass flux basically shows a cubic dependency with friction velocity, which distinguishes it from the quadratic dependence of blown sand movement. Moreover, the snow saltation flux is found to be largely sensitive to the particle size distribution since the suspension snow may restrain the saltation movement. This research could improve our understanding of the role of the mid-air collision mechanism in natural drifting snow.

scholarly journals Modular hemipelvic endoprosthesis with a sacral hook: a finite element study

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Bo Wang ◽  
Peidong Sun ◽  
Hao Yao ◽  
Jian Tu ◽  
Xianbiao Xie ◽  
...  
Keyword(s):  
Aseptic Loosening ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Biomechanical Properties ◽  
Stress Distributions ◽  
Three Dimensional Model ◽  
Connection Component ◽  
Static Conditions ◽  
Distribution Of Stress

Abstract Background A novel hemipelvic endoprosthesis with a sacral hook was introduced previously, and its clinical outcome with midterm follow-up showed decreased prosthesis-related complications, especially decreased rate of aseptic loosening. The aim of present study was to evaluate the role of a sacral hook in prosthesis stability and the biomechanical properties of this hemipelvic endoprosthesis. Methods A three-dimensional model of the postoperative pelvis was developed using computed tomography (CT) images. A force of 500 N was applied, and the distribution of stress and displacement was evaluated. Comparisons were performed to explore the role of the sacral hook in prosthesis stability. Prosthesis improvement was simulated to reduce unexpected breakage of the pubic connection plate. Results In the reconstructed hemipelvis, stress distributions were concentrated on the superior area of the acetabulum, sacral connection component, and sacral hook. A maximum stress of 250 MPa was observed at the root of the sacral connection component. The sacral hook reduced the maximum stress and displacement by 14.1% and 32.5%, respectively, when the prosthesis was well fixed and by 10.0% and 42.1%, respectively, when aseptic loosening occurred. Increasing the thickness of the pubic connection plate from 2 to 3.5 mm reduced the maximum stress by 32.0% and 15.8%, respectively. Conclusion A hemipelvic endoprosthesis with a sacral hook fulfills the biomechanical demands of the hemipelvis and is safe under static conditions. The sacral hook is important for prosthesis stability. Increasing the thickness of the pubic connection plate can reduce the maximum stress and risk of fatigue breakage.

Modelling of sulfuric acid and ammonium sulfate aerosol formation in the aerrea2 reactor

1998 ◽  
Vol 29 ◽  
pp. S87-S88
Author(s):  
Martin Wilck ◽  
Frank Stratmann ◽  
Lars Asbjørn Larsen ◽  
Rita Van Dingenen ◽  
Frank Raes
Keyword(s):  
Sulfuric Acid ◽  
Ammonium Sulfate ◽  
Sulfate Aerosol ◽  
Aerosol Formation

scholarly journals Substrate (aglycone) specificity of human cytosolic beta-glucosidase

2003 ◽  
Vol 373 (1) ◽  
pp. 41-48 ◽  
Author(s):  
Jean-Guy BERRIN ◽  
Mirjam CZJZEK ◽  
Paul A. KROON ◽  
W. Russell MCLAUCHLAN ◽  
Antoine PUIGSERVER ◽  
...  
Keyword(s):  
Structural Model ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Amino Acid Residues ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mutant Proteins ◽  
Metabolizing Enzyme ◽  
Beta Glucosidase

Human cytosolic β-glucosidase (hCBG) is a xenobiotic-metabolizing enzyme that hydrolyses certain flavonoid glucosides, with specificity depending on the aglycone moiety, the type of sugar and the linkage between them. Based upon the X-ray structure of Zea mays β-glucosidase, we generated a three-dimensional model of hCBG by homology modelling. The enzyme exhibited the (β/α)8-barrel fold characteristic of family 1 β-glucosidases, with structural differences being confined mainly to loop regions. Based on the substrate specificity of the human enzymes, sequence alignment of family 1 enzymes and analysis of the hCBG structural model, we selected and mutated putative substrate (aglycone) binding site residues. Four single mutants (Val168→Tyr, Phe225→Ser, Tyr308→Ala and Tyr308→Phe) were expressed in Pichia pastoris, purified and characterized. All mutant proteins showed a decrease in activity towards a broad range of substrates. The Val168→Tyr mutation did not affect Km on p-nitrophenyl (pNP)-glycosides, but increased Km 5-fold on flavonoid glucosides, providing the first biochemical evidence supporting a role for this residue in aglycone-binding of the substrate, a finding consistent with our three-dimensional model. The Phe225→Ser and Tyr308→Ala mutations, and, to a lesser degree, the Tyr308→Phe mutation, resulted in a drastic decrease in specific activities towards all substrates tested, indicating an important role of those residues in catalysis. Taken together with the three-dimensional model, these mutation studies identified the amino-acid residues in the aglycone-binding subsite of hCBG that are essential for flavonoid glucoside binding and catalysis.

scholarly journals Make-Belief in Language and Verity of Legitimized Oppression: A Critical Analysis of Selected Extracts From Anita Shreve's Body Surfing

2018 ◽  
Vol III (I) ◽  
pp. 298-324
Author(s):  
Abdul Waheed Qureshi ◽  
Rab Nawaz Khan
Keyword(s):  
Critical Discourse Analysis ◽  
Meaning Making ◽  
Three Dimensional ◽  
Critical Discourse ◽  
The Novel ◽  
Three Dimensional Model ◽  
Dominant Ideology ◽  
Truth Claim ◽  
Opposite Gender

The research in hand is a textual analysis of the novel Body Surfing by Anita Shreve which explains the role of language in the construction of an ideology as reality. The aim is to highlight the construction of a certain concept or ideology as a dominant truth claim in society through discourse and how is it blindly followed by all the members without the least strife to change that socalled dominant ideology. Language as a major agent in the construction and perpetuation of an ideology is forever the discourse of those who are in power. This research will propound the discourse active behind the verity of 'oppression' done to women as taken-for-granted and fair. By employing Critical Discourse Analysis (CDA) as research method, the study will critically examine the role of language in legalizing women oppression. We have cultivated the idea of 'women as weak' into something real, that has come to us generation after generation, through language. This supposition provides theoretical underpinnings for the research, which is arrived at through CDA by treating language post-structurally. The literature analyzed highlights the role of language in the process of meaning-making by considering it to convey reality. The various words and phrases from the extracts in hand with contextual and conceptual affiliation, are dealt with under the backdrop of Fairclough's (1992) Three Dimensional Model of CDA, which results in the recognition of oppression thought as legitimate by the ultimate use of language. The analysis done under the backdrop of poststructuralism will show that language is not the depiction of maximum reality rather; it is we, the users of language, who make it real by considering some concepts as truth and others as myth. The paper concludes that the opposite gender is actually oppressed and that this oppression is not given, rather the constructed one. CDA challenges this oppression and declares it the work of language only. It (language) has no signs of reality, subsistence or truth.

Media and Religious Tourism

2021 ◽  
pp. 210-231
Author(s):  
Rizwan Shabbir ◽  
Aysha Batool
Keyword(s):  
Thematic Analysis ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Tourist Behavior ◽  
Visitor Management ◽  
Religious Tourism ◽  
The Subject ◽  
Socio Economic Impact ◽  
Research Domains

This chapter aims at presenting a thematic analysis of 64 research articles on religious tourism published from 2009 to 2020 by adopting a systematic literature review method. The results indicate that prominent topics discussed were amplification of concepts, tourist motivations, and experience. The evolution of religious tourism concept through nexus of diverse scholarly terms, related domains, and religious practices needs a comprehensive literary debate to refine the subject. The socio-economic impact of religious tourism also calls for the enrichment of topics on scholarly and practical grounds. Issues such as host and tourist behavior, social interaction, visitor management, marketing components, and the role of media need to be explored for the progression of religious tourism in line with sustainability. The chapter contributes to the literature by proposing a three-dimensional model focusing on the role of media and potential research domains for further exploration.

scholarly journals Asp218 participates with Asp213 to bind a Ca2+ atom into the S1 subsite of aminopeptidase A: a key element for substrate specificity

2008 ◽  
Vol 416 (1) ◽  
pp. 37-46 ◽  
Author(s):  
Cédric Claperon ◽  
Raphael Rozenfeld ◽  
Xavier Iturrioz ◽  
Nicolas Inguimbert ◽  
Mayumi Okada ◽  
...  
Keyword(s):  
Rational Design ◽  
Three Dimensional ◽  
Antihypertensive Agents ◽  
Three Dimensional Model ◽  
Stimulatory Action ◽  
Acidic Residues ◽  
Aminopeptidase A ◽  
Strict Specificity ◽  
New Generation

APA (aminopeptidase A; EC 3.4.11.7) is a membrane-bound zinc metallopeptidase, also activated by Ca2+, involved in the formation of brain angiotensin III, which exerts a tonic stimulatory action on the central control of blood pressure in hypertensive animals. In the present study, in the three-dimensional model of the ectodomain of mouse APA, we docked the specific APA inhibitor glutamate phosphonate, in the presence of Ca2+. The model showed the presence of one Ca2+ atom in an hydrophilic pocket corresponding to the S1 subsite in which the lateral chain of the inhibitor is pointing. In this pocket, the Ca2+ atom was hexaco-ordinated with the acidic side chains of Asp213 and Asp218, the carbonyl group of Glu215 and three water molecules, one of them being engaged in a hydrogen bond with the negatively charged carboxylate side chain of the inhibitor. Mutagenic replacement of Asp213 and Asp218 with a conservative residue maintained the ability of mutated APAs to be activated by Ca2+. However, the replacement by a non-conservative residue abolished this property, demonstrating the crucial role of these residues in Ca2+ binding. We also showed the involvement of these residues in the strict specificity of APA in the presence of Ca2+ for N-terminal acidic residues from substrates or inhibitors, since mutagenic replacement of Asp213 and Asp218 induced a decrease of the inhibitory potencies of inhibitors homologous with acidic residues. Finally, this led to the rational design of a new potent APA inhibitor, NI926 (Ki=70 nM), which allowed us to precisely localize Asp213 at the entrance and Asp218 at the bottom of the S1 subsite. Taken together, these data provide new insight into the organization and functional role of the APA S1 subsite and will allow the design of pharmacophore of the inhibitor, helpful for the development of a new generation of APA inhibitors as central-acting antihypertensive agents.

The Investigation of Semi-Three-Dimensional Heat Transfer Modeling in Microcombustors

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
A. Fanaee ◽  
J. A. Esfahani
Keyword(s):  
Peclet Number ◽  
Flame Structure ◽  
Flame Temperature ◽  
Three Dimensional ◽  
Combustion Model ◽  
Three Dimensional Model ◽  
Péclet Number ◽  
Heat Transfers ◽  
Determining Factor

This paper presents a three-dimensional combustion model in the microcombustors. In this research, the flame structure is composed of three zones: a preheat zone, a reaction zone, and, finally, a post-flame zone. The governing equations are solved in these zones using the required boundary and matching conditions, which are achieved from nonasymptotic or asymptotic approach. Moreover, the role of Peclet number as a determining factor in the microcombustor performance is analyzed, and is found that by the increase of the Peclet number, the dimensionless flame temperature rises. Consequently, this three-dimensional model has provided a great description for the Peclet number, the dimensions, the asymptotic or nonasymptotic assumption effects, and the structural heat conduction in the microcombustors. The results are validated with those obtained from two-dimensional heat transfers modeling, and are in accordance with data published by former researchers.

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