scholarly journals Immersion Freezing Ability of Freshly Emitted Soot with Various Physico-Chemical Characteristics

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1173
Author(s):  
John Falk ◽  
Kimmo Korhonen ◽  
Vilhelm B. Malmborg ◽  
Louise Gren ◽  
Axel C. Eriksson ◽  
...  
Keyword(s):  
Soot Particle ◽  
Particle Density ◽  
Particle Surface ◽  
Chemical Properties ◽  
Biomass Combustion ◽  
Soot Particles ◽  
Physico Chemical ◽  
Effective Particle ◽  
Wide Range ◽  
Immersion Freezing

The immersion freezing ability of soot particles has in previous studies been reported in the range of low/insignificant to very high. The aims of this study were to: (i) perform detailed physico-chemical characterisation of freshly produced soot particles with very different properties, (ii) investigate the immersion freezing ability of the same particles, and (iii) investigate the potential links between physico-chemical particle properties and ice-activity. A miniCAST soot generator was used to produce eight different soot samples representing a wide range of physico-chemical properties. A continuous flow diffusion chamber was used to study each sample online in immersion mode over the temperature (T) range from −41 to −32 °C, at a supersaturation of about 10% with respect to liquid water. All samples exhibited low to no heterogeneous immersion freezing. The most active sample reached ice-activated fractions (AF) of 10−3 and 10−4 at temperatures of 1.7 and 1.9 K , respectively, above the homogeneous freezing temperature. The samples were characterized online with respect to a wide range of physico-chemical properties including effective particle density, optical properties, particle surface oxidation and soot maturity. We did observe indications of increasing immersion freezing ice-activity with increasing effective particle density and increasing particulate PAH fraction. Hence, those properties, or other properties co-varying with those, could potentially enhance the immersion freezing ice-activity of the studied soot particle types. However, we found no significant correlation between the physico-chemical properties and the observed ice-nucleating ability when the particle ensemble was extended to include previously published results including more ice-active biomass combustion soot particles. We conclude that it does not appear possible in general and in any straightforward way to link observed soot particle physico-chemical properties to the ice-nucleating ability using the online instrumentation included in this study. Furthermore, our observations support that freshly produced soot particles with a wide range of physico-chemical properties have low to insignificant immersion freezing ice-nucleating ability.

Immersion Freezing Effi ciency of Soot Particles with Various Physico-Chemical Properties

2007 ◽  
pp. 418-422
Author(s):  
O. B. Popovicheva ◽  
N. M. Persiantseva ◽  
E. D. Kireeva ◽  
T. D. Khokhlova ◽  
N. K. Shonija ◽  
...  
Keyword(s):  
Chemical Properties ◽  
Soot Particles ◽  
Physico Chemical ◽  
Effi Ciency ◽  
Immersion Freezing

scholarly journals A review on conductometric studies of electrolytes in mixed solvent systems to understand ion-ion and ion-solvent interactions

2020 ◽  
Vol 10 (3) ◽  
pp. 5355-5360
Keyword(s):  
Mixed Solvent ◽  
Mixed Solvents ◽  
Chemical Properties ◽  
Electrolyte Solutions ◽  
Molar Conductance ◽  
Extensive Literature ◽  
Solvent Interactions ◽  
Physico Chemical ◽  
Wide Range ◽  
Solvent Systems

The study of ion- solvent interaction is of much importance to investigate the nature of different solutions. Measurement of electrical conductivity and evaluation of physico-chemical properties, such as molar conductance, limiting molar conductance, ion-pair association, Walden product etc. shade light on different intermolecular interactions present in electrolyte solutions. Solvation properties can be varied by mixing two or more solvents. An extensive literature survey on conductometric studies has been carried out on different electrolytes dissolved in a wide range of mixed solvent systems. The reported results show that strong solute-solute, solute-solvent and solvent-solvent interactions are responsible for the physico- chemical behavior of a solution in mixed solvents.

Soil fertility and leaf nutrient status of litchi orchard sites

2021 ◽  
Vol 30 (2) ◽  
pp. 141-149
Author(s):  
Tasnim Zannat ◽  
Farhana Firoz Meem ◽  
Rubaiat Sharmin Promi ◽  
Umme Qulsum Poppy ◽  
MK Rahman
Keyword(s):  
Particle Density ◽  
Organic Matter Content ◽  
Chemical Properties ◽  
Nutrient Status ◽  
Matter Content ◽  
Average Particle ◽  
Total N ◽  
Available N ◽  
Dominant Soil ◽  
Physico Chemical

Twelve soil and twelve leaf samples were collected from twelve litchi (Litchi chinensis Sonn.) orchards from different locations of Dinajpur to evaluate some physico-chemical properties and nutrient status of soil, and concentration of nutrients in litchi leaf. The pH of the soil varied from very strong acidic to medium acidic (4.8 - 5.7), organic matter content varied from 0.84 - 1.88%, EC varied from 302.4 - 310.2 μS/cm. The dominant soil textural class was clay loam. The average particle density was 2.49g/cm3. Total N, P, K and S in soils were 0.053 - 0.180%, 0.02 - 0.07%, 0.046 - 0.370 meq/100 g, and 0.015 - 0.028%, respectively. Available N, P, K, S, Zn, Fe, Mn and B in soils 30.40 - 57.8 mg/kg, 10.53 - 14.33 mg/kg, 0.03 - 0.32 meq/100 g, 20.03-34.80 mg/kg, 0.68-1.50 μg/g, 31.8 - 41.5 μg/g, 6.75 - 7.39 μg/g and 0.25-0.51 μg/g, respectively. The concentration of total N, P, K, S, Zn and Mn in the leaf were 1.74 - 2.20%, 0.11 - 0.188%, 0.104- 0.198%, 0.129 - 0.430%, 12 - 14 μg/g and 30 - 74 μg/g, respectively. The overall results indicated that the fertility status of the soils under the litchi plantation in the Dinajpur area are medium fertile. So, farmers could be advised to grow litchi plants after applying amendments to the soils to improve the physico-chemical properties in the Dinajpur area of Bangladesh. Dhaka Univ. J. Biol. Sci. 30(2): 141-149, 2021 (July)

scholarly journals Controllable synthesis of pomelo peel-based aerogel and its application in adsorption of oil/organic pollutants

2019 ◽  
Vol 6 (2) ◽  
pp. 181823 ◽  
Author(s):  
Guangyu Shi ◽  
Yizhu Qian ◽  
Fengzhi Tan ◽  
Weijie Cai ◽  
Yuan Li ◽  
...  
Keyword(s):  
High Speed ◽  
Chemical Properties ◽  
Absorption Capacity ◽  
High Porosity ◽  
X Ray Diffraction ◽  
Water Separation ◽  
Physico Chemical ◽  
Wide Range ◽  
Oil Water Separation ◽  
Oil Water

Oil/water separation is a field of high significance as it might efficiently resolve the contamination of industrial oily wastewater and other oil/water pollution. In this paper, an environmentally-friendly hydrophobic aerogel with high porosity and low density was successfully synthesized with renewable pomelo peels (PPs) as precursors. Typically, a series of sponge aerogels (HPSA-0, HPSA-1 and HPSA-2) were facilely prepared via high-speed dispersion, freeze-drying and silanization with methyltrimethoxysilane. Indeed, the physical properties of aerogel such as density and pore diameter could be tailored by different additives (filter paper fibre and polyvinyl alcohol). Hence, their physico-chemical properties including internal morphology and chemical structure were characterized in detail by Fourier transform infrared, Brunauer–Emmett–Teller, X-ray diffraction, scanning electron microscope, Thermal gravimetric analyzer (TG) etc. Moreover, the adsorption capacity was further determined and the results revealed that the PP-based aerogels presented excellent adsorption performance for a wide range of oil products and/or organic solvents (crude oil 49.8 g g −1 , soya bean oil 62.3 g g −1 , chloroform 71.3 g g −1 etc.). The corresponding cyclic tests showed the absorption capacity decreased slightly from 94.66% to 93.82% after 10 consecutive cycles, indicating a high recyclability.

Acute Inhalation Toxicity of Some Halogenated and Non-halogenated Hydrocarbons

1982 ◽  
Vol 1 (3) ◽  
pp. 239-247 ◽  
Author(s):  
D.G. Clark ◽  
D.J. Tinston
Keyword(s):  
Chemical Properties ◽  
Degree Of Saturation ◽  
Halogenated Hydrocarbons ◽  
Inhalation Toxicity ◽  
Saturated Vapour Pressure ◽  
Physico Chemical ◽  
Wide Range ◽  
The Central Nervous System ◽  
Thermodynamic Scale ◽  
Rat Cns

1 The relative potency of effect of a wide range of halogenated and unsubstituted hydrocarbons on the central nervous system (CNS) and the heart of experimental animals have been determined. 2 The chemicals used caused either stimulation or depression of the rat CNS after 10 minutes' inhalation of concentrations ranging from 0.24% to > 80% (v/v), and cardiac sensitization in dogs after 5 minutes' inhalation of 0.12% to approximately 80% (v/v). 3 The toxicity could not be correlated with chemical structure, molecular weight, the presence or absence of various halogen atoms or the degree of saturation, but it was inversely related to the saturated vapour pressure. When the results were expressed on a thermodynamic scale the chemicals had similar potencies at relative saturations of 0.004 to 0.04 4 It is suggested that the effects of these chemicals on the CNS and the heart are probably structurally non-specific, and the chemicals may be regarded as physical toxicants whose effects are predictable from their physico-chemical properties.

scholarly journals Lactoperoxidase: physico-chemical properties, occurrence, mechanism of action and applications

2000 ◽  
Vol 84 (S1) ◽  
pp. 19-25 ◽  
Author(s):  
Klaas D. Kussendrager ◽  
A. C. M. van Hooijdonk
Keyword(s):  
Mammalian Cells ◽  
Bovine Milk ◽  
Chemical Properties ◽  
Mechanisms Of Action ◽  
Industrial Processes ◽  
Physico Chemical ◽  
Lactoperoxidase System ◽  
Wide Range ◽  
Occurrence Mechanism ◽  
Micro Organisms

Lactoperoxidase (LP) is one of the most prominent enzymes in bovine milk and catalyses the inactivation of a wide range of micro-organisms in the lactoperoxidase system (LP-s). LP-systems are also identified as natural antimicrobial systems in human secretions such as saliva, tear-fluid and milk and are found to be harmless to mammalian cells. The detailed molecular structure of LP is identified and the major products generated by the LP-s and their antimicrobial action have been elucidated for the greater part. In this paper several aspects of bovine LP and LP-s are discussed, including physico-chemical properties, occurrence in milk and colostrum and mechanisms of action. Since the introduction of industrial processes for the isolation of LP from milk and whey the interest in this enzyme has increased considerably and attention will be paid to potential and actual applications of LP-systems as biopreservatives in food and other products.

scholarly journals DIVERSITY AND SIMILARITY AMONG CYANOBACTERIA ASSEMBLAGES FROM SELECTED AQUATIC ECOSYSTEMS IN SARAWAK USING β –INDICES

2016 ◽  
Vol 1 (1) ◽  
pp. 28-37
Author(s):  
Mohd Nasarudin Harith ◽  
Ruhana Hassan
Keyword(s):  
Aquatic Ecosystem ◽  
Aquatic Ecosystems ◽  
Chemical Properties ◽  
Artificial Lake ◽  
Environmental Characteristics ◽  
Β Diversity ◽  
Physico Chemical ◽  
Wide Range ◽  
Aquaculture Ponds

A study was carried out to evaluate the diversity and similarity of cyanobacterial populations in selected Sarawak aquatic ecosystem using β-indices. Eight stations including aquaculture ponds, cage cultures, waterfall and artificial lake located in Serian, Bau and Batang Ai areas were selected. A total of 43 species belonging to 30 genera of cyanobacteria were recorded. The most distributed pattern among all sampling stations belongs to the genera Chroococcus, Lyngbya, Nostoc and Oscillatoria. The highest β diversity values were found among non-contiguous stations. Besides, no identical or totally different cyanobacteria diversity values were obtained among those non-contiguous stations. The highest β diversity value (0.84) was found among stations with contrasting environmental characteristics. The wide range of β-diversity and similarity suggested that different locations and types of aquatic ecosystems may have variations in physico-chemical properties of the water and eventually lead to the different composition of cyanobacteria.

Shungite Carbon Nanoparticles as Modifiers of Zns:Cu Phosphor, Based on Analysis of the EPR Spectral Lines of Mn+2

2021 ◽  
Vol 1031 ◽  
pp. 201-208
Author(s):  
S.P. Rozhkov ◽  
Natalia N. Rozhkova ◽  
Maxim М. Sychov
Keyword(s):  
Integral Intensity ◽  
Subsurface Layer ◽  
Particle Surface ◽  
Chemical Properties ◽  
Spectral Lines ◽  
Nanoparticle Concentration ◽  
Epr Spectrum ◽  
Physico Chemical ◽  
Saturation Power ◽  
Shungite Carbon

Water dispersions of shungite carbon (ShC) nanoparticles were used for modifying the particle surface of ZnS:Cu, commercial electrophosphor. The EPR spectrum of ZnS:Cu powder has parameters consistent with the paramagnetic centers of Mn+2. Modifying the phodphor surface with ShC nanoparticles results in a non-monotonic change in line width, amplitude and integral intensity caused by nanoparticle concentration, which correlates with variations in the brightness of electroluminescence. Variations in the parameters of spectral lines with nanoparticle concentration and UHF saturation power are interpreted in terms of modification and creation of additional dislocations in the subsurface layer of phosphor with new physico-chemical properties.

Physico-chemical and hydrological properties of soilless substrates

2021 ◽  
Vol 42 (3) ◽  
pp. 700-704
Author(s):  
Anbarasu Mariyappillai ◽  
◽  
Gurusamy Arumugam ◽  
Keyword(s):  
Organic Carbon ◽  
Total Organic Carbon ◽  
Natural Fiber ◽  
Particle Density ◽  
Colorimetric Method ◽  
Chemical Properties ◽  
Maximum Level ◽  
Total Porosity ◽  
Physico Chemical ◽  
And Chemical Properties

Aim: To evaluate the physico-chemical and hydrological characteristics of cocopith, perlite, vermicullite, vermicompost, sand, rice husk, paddy straw, saw dust and rock wool for using them as substrates for soilless agriculture. Methodology: The soilless substrates were initially evaluated for pH and EC, and then estimated for total organic carbon by dry combustion method, total nitrogen by Kjeldahl digestion method, potassium by atomic absorption and phosphorus by colorimetric method. The hydrological properties of substrates were estimated by Keen - Rackzowski box method. Results: The desirable level of physical properties of bulk density (0.47 gm cm-3), particle density (0.63 gm cm-3), total porosity (75.81%) and chemical properties of pH (6.23), EC (5.02 dS m-1), total organic carbon (36.39 %), and other properties were noticed under cocopith. The maximum level of water holding capacity (769.30 %) and volume of expansion (185.78 %) was registered by cocopith. Interpretation: Cocopith has favourable hydrological properties with desirable level of physical and chemical properties, which makes it the best medium for soilless agriculture. Coconut fiber is a characteristic natural fiber from the external husk of coconut and its extraction process also without polluting nature.

scholarly journals Exploring New Synthetic Strategies for the Production of Advanced Complex Inorganic Nanocrystals

2015 ◽  
Vol 229 (1-2) ◽  
Author(s):  
Neus G. Bastús ◽  
Edgar Gonzalez ◽  
Joan Esteve ◽  
Jordi Piella ◽  
Javier Patarroyo ◽  
...  
Keyword(s):  
Materials Science ◽  
Chemical Properties ◽  
Synthetic Methods ◽  
Colloidal Synthesis ◽  
Hollow Structures ◽  
Physico Chemical ◽  
Composition And Structure ◽  
Wide Range ◽  
Potential Applicability ◽  
New Generation

AbstractThe design of new protocols for the colloidal synthesis of complex nanocrystals (NCs) with advanced functionalities, comprising both hybrid and hollow structures, and the study of their fundamental properties is of paramount importance for the development of a new generation of nanostructured materials. The possibility of tailoring the dimensional regime of NCs, along with its composition and structure, represents a landmark achievement in the control of their unique physico-chemical properties. These properties, alongside with the ability to cheaply produce high quality NCs in fairly large amounts by wet-chemistry techniques, leads to their potential applicability from materials science to nanomedicine. Within this context, this review is focused on describing a successful framework for designing synthetic strategies for the production of advanced complex NCs, integrating the development of new synthetic methods with its structural characterization, monitoring of their properties, and study of its reactivity. As a result, it is expected to provide new routes to produce robust and easy-to-process NCs in a wide range of sizes, shapes and configurations that can be explored to achieve the combination of all degrees of control, aiming to produce a complete and diverse library of material combinations that will expand its applicability in a wide diversity of fields.

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