Characterization of tandem aerosol classifiers for selecting particles: implication for eliminating multiple charging effect

Abstract. Accurate particle classification plays a vital role in aerosol studies. Differential mobility analyzer (DMA), centrifugal particle mass analyzer (CPMA) and aerodynamic aerosol classifier (AAC) are commonly used to select particles with a specific size or mass. However, multiple charging effect cannot be entirely avoided either using individual technique or using tandem system such as DMA-CPMA, especially when selecting soot particles with fractal structures. In this study, we demonstrate the transfer functions of DMA-CPMA and DMA-AAC systems, as well as the potential multiple charging effect. Our results show that the ability to remove multiply charged particles mainly depends on particles morphology and instruments setups of DMA-CPMA system. Using measurements from soot experiments and literature data, a general trend in the appearance of multiple charging effect with decreasing size when selecting aspherical particles was observed. Otherwise, our results indicated that the ability of DMA-AAC to resolve particles with multiple charges is mainly related to the resolutions of classifiers. In most cases, DMA-AAC can eliminate multiple charging effect regardless of the particle morphology, while particles with multiple charges can be selected when decreasing resolutions of DMA and AAC. We propose that the multiple charging effect should be reconsidered when using DMA-CPMA or DMA-AAC system in estimating size and mass resolved optical properties in the field and lab experiments.

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Supplementary material to "Characterization of tandem aerosol classifiers for selecting particles: implication for eliminating multiple charging effect"

10.5194/amt-2021-436-supplement ◽

2022 ◽

Author(s):

Yao Song ◽

Xiangyu Pei ◽

Huichao Liu ◽

Jiajia Zhou ◽

Zhibin Wang

Keyword(s):

Multiple Charging ◽

Supplementary Material ◽

Charging Effect

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Cryomicroscopy of multiphase latices

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089615 ◽

1991 ◽

Vol 49 ◽

pp. 1060-1061

Author(s):

O. L. Shaffer ◽

M.S. El-Aasser ◽

C. L. Zhao ◽

M. A. Winnik ◽

R. R. Shivers

Keyword(s):

Electron Microscopy ◽

Radiation Damage ◽

Freeze Fracture ◽

Particle Morphology ◽

Second Stage ◽

Transmission Electron ◽

Important Approach ◽

Carbon Coated ◽

Preparation Techniques

Transmission electron microscopy is an important approach to the characterization of the morphology of multiphase latices. Various sample preparation techniques have been applied to multiphase latices such as OsO4, RuO4 and CsOH stains to distinguish the polymer phases or domains. Radiation damage by an electron beam of latices imbedded in ice has also been used as a technique to study particle morphology. Further studies have been developed in the use of freeze-fracture and the effect of differential radiation damage at liquid nitrogen temperatures of the latex particles embedded in ice and not embedded.Two different series of two-stage latices were prepared with (1) a poly(methyl methacrylate) (PMMA) seed and poly(styrene) (PS) second stage; (2) a PS seed and PMMA second stage. Both series have varying amounts of second-stage monomer which was added to the seed latex semicontinuously. A drop of diluted latex was placed on a 200-mesh Formvar-carbon coated copper grid.

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New Results on the Characterization of Strictly Positive Real Matrix Transfer Functions

IEEE Transactions on Automatic Control ◽

10.1109/tac.2020.2980936 ◽

2021 ◽

Vol 66 (1) ◽

pp. 335-339

Author(s):

Mojtaba Hakimi-Moghaddam ◽

Augusto Ferrante

Keyword(s):

Transfer Functions ◽

Real Matrix ◽

Positive Real ◽

Strictly Positive Real

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Electrothermal Characterization of Doped-Si Heated Microcantilevers Under Periodic Heating Operation

Journal of Heat Transfer ◽

10.1115/1.4032531 ◽

2016 ◽

Vol 138 (5) ◽

Author(s):

Sina Hamian ◽

Andrew M. Gauffreau ◽

Timothy Walsh ◽

Jungchul Lee ◽

Keunhan Park

Keyword(s):

Microelectromechanical Systems ◽

Transfer Functions ◽

Design Parameters ◽

Periodic Heating ◽

Element Analysis ◽

Full Spectrum ◽

Frequency Dependent ◽

Thermal Transfer ◽

Fea Model

This paper reports the frequency-dependent electrothermal behaviors of a freestanding doped-silicon heated microcantilever probe operating under periodic (ac) Joule heating. We conducted a frequency-domain finite-element analysis (FEA) and compared the steady periodic solution with 3ω experiment results. The computed thermal transfer function of the cantilever accurately predicts the ac electrothermal behaviors over a full spectrum of operational frequencies, which could not be accomplished with the 1D approximation. In addition, the thermal transfer functions of the cantilever in vacuum and in air were compared, through which the frequency-dependent heat transfer coefficient of the air was quantified. With the developed FEA model, design parameters of the cantilever (i.e., the size and the constriction width of the cantilever heater) and their effects on the ac electrothermal behaviors were carefully investigated. Although this work focused on doped-Si heated microcantilever probes, the developed FEA model can be applied for the ac electrothermal analysis of general microelectromechanical systems.

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Virus and virus-like diseases of grapevine in Hungary

International Journal of Horticultural Science ◽

10.31421/ijhs/17/3/954 ◽

2011 ◽

Vol 17 (3) ◽

Cited By ~ 1

Author(s):

J. Lázár ◽

Gy. D. Bisztray

Keyword(s):

Energy Metabolism ◽

Host Cell ◽

Particle Morphology ◽

Plant Viruses ◽

Diagnostic Methods ◽

Economic Damage ◽

Mixed Infections ◽

Disease Symptoms ◽

The World

Viruses and viroids are submicroscopic infectious particles which can cause disease symptoms on grapevine. These parasites are depending completely on the energy metabolism of the plant cell. To enter the host cell plant viruses depend on injuries or on transmission via invertebrates (insects, nematodes, etc.). Viruses are classified by many characters including particle morphology, host range and information content of the genome. At present about 70 viruses including 7 viroids infecting grapevine are known. In single or mixed infections they are potentially detrimental to the quality and quantity of grape production in any growing area of the world. Some viruses can cause severe economic damage in vineyards. In Hungary many important viruses and viroids have been detected in grape. This review summarises characteristics of viruses and the results of detection and characterization of virus and virus like diseases of grapevine in Hungary. The identification of the causal agent, its transmission, geographical distribution and the development of the diagnostic methods are also discussed.

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Synthesis characterization and antibacterial studies of 4-aminoantipyrine schiff’s bases

International Journal of Applied Pharmaceutical Sciences and Research ◽

10.21477/ijapsr.v2i1.6908 ◽

2017 ◽

Vol 2 (01) ◽

pp. 8-14 ◽

Cited By ~ 1

Author(s):

K Sunand ◽

K Vinay Kumar ◽

K Ashwini ◽

P Suresh Kumar ◽

S Vishnu ◽

...

Keyword(s):

Antibacterial Activity ◽

Schiff Bases ◽

Vital Role ◽

Spectroscopic Techniques ◽

Schiff’S Bases ◽

Pharmacological Activities ◽

Schiff's Bases ◽

Ir Spectroscopic

Aim: To synthesize and evaluate 4-aminoantipyrine related schiff’s bases as antibacterial agents. Objective: To synthesize, purify, characterize and evaluate 4-aminoantipyrine. Method: Schiff bases derived from 4-aminoantipyrine play a vital role in biological and pharmacological activities. Knowing the importance of 4-aminoatipyrine schiff bases and their analogues wide varieties of bioactivities like analgesic, antiviral, antipyretic, anti-rheumatic, antimicrobial and anti-inflammatory activities have been widely studied. 4-aminoantipyrine compounds C1 (anisaldehyde), C2 (p-hydroxybenzaldehyde) and C3(vanillin) were prepared by condensation between 4-amino antipyrine and substituted aromatic benzaldehydes. The products were purified by recrystallization by using ethanol, characterized by IR spectroscopy. The N-H stretching in 4-aminoantipyrine is shown at 3430 cm-1 and -3325 cm-1. The -HC=N- stretching is observed in the range of 1508-1504 cm-1 The –OCH3 stretching is found at 1888 cm-1. 4-amino antipyrine related schiff’s bases evaluated their activity as antimicrobials in-vitro by spread plate method against E.coli. Schiff bases have potent antibacterial activity with gram negative bacteria E.coli. Results: Synthesis and characterization of a schiff bases derived from substituted benzaldehydes and 4-aminoantipyrine was evaluated and characterized with the IR spectroscopic techniques and schiff bases have shown potent antibacterial activity against E.Coli.

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Genetic and Developmental Characterization of Dmca1D, a Calcium Channel α1 Subunit Gene in Drosophila melanogaster

Genetics ◽

10.1093/genetics/148.3.1159 ◽

1998 ◽

Vol 148 (3) ◽

pp. 1159-1169

Author(s):

Daniel F Eberl ◽

Dejian Ren ◽

Guoping Feng ◽

Lori J Lorenz ◽

David Van Vactor ◽

...

Keyword(s):

Drosophila Melanogaster ◽

Calcium Channel ◽

Functional Significance ◽

Transmembrane Domain ◽

Vital Role ◽

Subunit Gene ◽

Channel Diversity ◽

Domain I ◽

Α1 Subunit

Abstract To begin unraveling the functional significance of calcium channel diversity, we identified mutations in Dmca1D, a Drosophila calcium channel α1 subunit cDNA that we recently cloned. These mutations constitute the l(2)35Fa lethal locus, which we rename Dmca1D. A severe allele, Dmca1DX10, truncates the channel after the IV-S4 transmembrane domain. These mutants die as late embryos because they lack vigorous hatching movements. In the weaker allele, Dmca1DAR66, a cysteine in transmembrane domain I-S1 is changed to tyrosine. Dmca1DAR66 embryos hatch but pharate adults have difficulty eclosing. Those that do eclose have difficulty in fluid-filling of the wings. These studies show that this member of the calcium channel α1 subunit gene family plays a nonredundant, vital role in larvae and adults.

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Morphogenesis of the bone marrow: fractal structures and diffusion- limited growth

Blood ◽

10.1182/blood.v87.12.5027.bloodjournal87125027 ◽

1996 ◽

Vol 87 (12) ◽

pp. 5027-5031 ◽

Cited By ~ 10

Author(s):

F Naeim ◽

F Moatamed ◽

M Sahimi

Keyword(s):

Bone Marrow ◽

Spatial Organization ◽

Fractal Dimensions ◽

Fractal Structures ◽

Diffusion Limited Aggregation ◽

Diffusion Limited ◽

Morphometric Analyses ◽

Cellular Area ◽

Pathologic Processes

Bone marrow (BM) provides a particular spatial organization that allows interaction between its various components. Characterization of the spatial patterns in the BM and understanding the mechanisms that give rise to them may play a role in better understanding of the BM pathologic processes. Morphometric analyses were performed in BM biopsy samples from 30 patients (16 men and 14 women) with an average age of 46 years, ranging from 17 to 77 years. The biopsies were obtained during the course of patient care to rule out BM involvement in a variety of hematologic disorders before or after therapy. Three different, but structurally interrelated, parameters were measured: (A) cellular area, (B) nuclear area, and (C) cell numbers. All three methods, in all cases, showed that the spatial structure of the BM is fractal. The average values of the fractal dimensions (Df) were 1.7 +/- 0.08, 1.64 +/- 0.1, and 1.69 +/- 0.04 for categories A, B, and C, respectively. The overall value of Df for the cellularity in the range of 40% to 60% was about 1.67 +/- 0.09. Fractal dimensions of 1.6 to 1.7 represent configurations that correspond to two-dimensional diffusion limited aggregation structures, suggesting that the structural configuration of hematopoietic cells is dependent on the diffusion of regulatory cytokines in the BM.

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