scholarly journals Effects Of Process Parameters On Cu Powder Synthesis Yield And Particle Size In A Wet-Chemical Process

2015 ◽  
Vol 60 (2) ◽  
pp. 1247-1250 ◽  
Author(s):  
Y.M. Shin ◽  
J.-H. Lee
Keyword(s):  
Particle Size ◽  
Ascorbic Acid ◽  
Chemical Process ◽  
Average Particle Size ◽  
Average Particle ◽  
Distilled Water ◽  
Water Mixture ◽  
Powder Synthesis ◽  
Wet Chemical ◽  
Synthesis Yield

Abstract This study presents a simple wet-chemical process to prepare several micron-size Cu powders. Moreover, changes in powder synthesis yield and particle size are examined with different solvents, synthesis temperatures, and amounts of reducing agent during the synthesis. As a reducing agent and capping agent, L-ascorbic acid and polyvinyl pyrrolidone were used, respectively. The yields in distilled water or an ethylene glycol (EG)/distilled water mixture were higher than that in EG alone, and the yield increased with increasing temperature owing to a lower Δ Gred value. Increasing the L-ascorbic acid concentration also increased the yield. The Cu powder synthesized in 3 h at 90°C in distilled water with 272.8 mM of L-ascorbic acid showed the lowest average particle size of 2.52 μm, indicating mechanisms of short burst nucleation and reduced growth via the increased reduction rate of Cu ions. It is estimated that the nucleation step was nearly completed within 10 min in this system. The Cu powders synthesized in an ethylene glycol/distilled water mixture presented an average particle size of 3.76 μm and the highest yield of 87.9%.

Synthesis of Several Micrometer-Size Cu Particles by a Green Wet Reduction Method

2014 ◽  
Vol 711 ◽  
pp. 210-213
Author(s):  
Jun Ho Hwang ◽  
Jong Hyun Lee
Keyword(s):  
Particle Size ◽  
Chemical Process ◽  
Reduction Method ◽  
Average Particle Size ◽  
Reducing Agent ◽  
Average Particle ◽  
Effective Agent ◽  
Powder Samples ◽  
Wet Chemical ◽  
Micrometer Size

Several micrmeter-size Cu powders were synthesized by a simple and green wet-chemical process. Moreover, changes in particle size are examined with different synthesis temperatures and amounts of gelatin reducing agent. All powder samples synthesized in this study were indexed as a Cu phase despite the synthesis was performed in air. The particle size decreased with increasing the gelatin content in principle, indicating that gelatin is an effective agent in suppressing aggregation between synthesized particles. The smallest average particle size was 1.53 μm.

scholarly journals STUDY PARTICLE SIZE DISTRIBUTION OF ERODING POWDER LEAD BRONZES OBTAINED IN DISTILLED WATER

2018 ◽  
Vol 22 (4) ◽  
pp. 42-49
Author(s):  
E. V. Ageev ◽  
A. S. Pereverzev ◽  
A. S. Osminina ◽  
I. Yu. Grigorov
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Discharge Zone ◽  
Powder Materials ◽  
Average Particle ◽  
Distilled Water ◽  
Powder Particles ◽  
Local Exposure ◽  
Finely Dispersed Powder ◽  
Powder Lead

The article is devoted to the current problem of processing waste of conductive materials, in particular lead bronze, which accumulates in large quantities at enterprises. A promising method for processing any conductive material, characterized by wastelessness, ecological purity of the process, and low energy costs, is the method of electroerosive dispersion. The essence of the method of electroerosive dispersion is the destruction of current-conducting material as a result of local exposure to short-term electrical discharges between the electrodes. In the discharge zone, under high temperatures, heating, melting and partial evaporation of the material occurs, resulting in the formation of finely dispersed powder particles. At the same time, the electrical parameters of the installation will affect the productivity of the process for obtaining powder materials: the voltage at the electrodes, the capacitance of the discharge capacitors, and the repetition rate. The article presents the results of the analysis of particles of powdered lead bronze obtained by the method of electroerosive dispersion in distilled water from wastes, using the laser analyzer of particle sizes "Analysette 22 NanoTec". It has been experimentally established that the average particle size of powdered lead bronze is 9.73 μm, the arithmetic value is 9.731 μm. It was also found that the elongation coefficient (elongation) of particles with a size of 7.188 μm is 1.50.

Structure and properties of electroerosive materials from lead bronze waste BrS30, obtained in oxygen- and carbon-containing media

2021 ◽  
pp. 309-312
Author(s):  
E.V. Ageev ◽  
A.S. Pereverzev
Keyword(s):  
Particle Size ◽  
Chemical Composition ◽  
Average Particle Size ◽  
Experimental Studies ◽  
Average Particle ◽  
Distilled Water ◽  
Structure And Properties ◽  
Technological Parameters ◽  
Elliptical Shape

The results of experimental studies of the structure and properties of electroerosive materials from lead bronze waste BrS30 obtained in oxygen- and carbon-containing media are presented. The influence of the chemical composition of liquids and technological parameters of dispersion on the properties of the resulting electroerosive materials is shown. In particular, a part of oxygen is present on the surface of particles obtained in distilled water, and part of carbon is present in lighting kerosene. The average particle size obtained in lighting kerosene is 1.2 times higher than the average particle size obtained in distilled water. The particles of the BrS30 alloy dispersed by electroerosion have a regular spherical, elliptical shape and agglomerates.

Effect of Ascorbic Acid and Particle Size on Iron Absorption from Ferric Pyrophosphate in Adult Women

2004 ◽  
Vol 74 (4) ◽  
pp. 294-300 ◽  
Author(s):  
Fidler ◽  
Davidsson ◽  
Zeder ◽  
Walczyk ◽  
Marti ◽  
...  
Keyword(s):  
Particle Size ◽  
Ascorbic Acid ◽  
Iron Absorption ◽  
Average Particle Size ◽  
Relative Bioavailability ◽  
Molar Ratio ◽  
Average Particle ◽  
Adult Women ◽  
Mean Particle Size ◽  
Ferric Pyrophosphate

The effects of added ascorbic acid and particle size on iron absorption from ferric pyrophosphate were evaluated in adult women (9–10 women/study) based on erythrocyte incorporation of iron stable isotopes (57Fe or 58Fe) 14 days after administration. Three separate studies were made with test meals of iron-fortified infant cereal (5 mg iron/meal) and the results are presented as geometric means and relative bioavailability values (RBV, FeSO4 = 100%). The results of study 1 showed that iron absorption was significantly lower from ferric pyrophosphate (mean particle size 8.5 mum) than from FeSO4 in meals without ascorbic acid (0.9 vs. 2.6%, p < 0.0001, RBV 36%) and in the same meals with ascorbic acid added at a 4:1 molar ratio relative to fortification iron (2.3 vs. 9.7%, p < 0.0001, RBV 23%). Ascorbic acid increased iron absorption from ferric pyrophosphate slightly less (2.6-fold) than from FeSO4 (3.7-fold) (p < 0.05). In studies 2 and 3, RBV of ferric pyrophosphate with an average particle size of 6.7 mum and 12.5 mum was not significantly different at 52 and 42% (p > 0.05), respectively. In conclusion, the addition of ascorbic acid increased fractional iron absorption from ferric pyrophosphate significantly, but to a lesser extent than from FeSO4. Decreasing the mean particle size to 6.7 mum did not significantly increase iron absorption from ferric pyrophosphate.

scholarly journals Influence of Mn2+ Concentration and UV Irradiation Time on the Luminescence Properties of Mn-doped ZnS Nanocrystals

2009 ◽  
Vol 19 (1) ◽  
pp. 33-38
Author(s):  
Tran Minh Thi
Keyword(s):  
Particle Size ◽  
Uv Irradiation ◽  
Single Phase ◽  
Irradiation Time ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Wet Chemical Method ◽  
Wet Chemical ◽  
Mn Doped

ZnS:Mn were prepared by wet chemical method with Mn doping concentration from 0 at% to 12 at%. The structure and particle size of the obtained powders were measured by X-ray diffraction (XRD) and scanning electron microscopy (SEM) and shown that all samples are single phase with sphalerite crystal structure and average particle size of about 5 - 7 nm. The dependence of Mn2+ ions doped concentration, and UV irradiation time on the luminescent intensity of ZnS:Mn nanocrystals was discussed.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

Azithromycin nanosuspension preparation using evaporative precipitation into aqueous solution (EPAS) method and its comparative dissolution study

2020 ◽  
Vol 17 ◽  
Author(s):  
Mohammad Hossain Shariare ◽  
Tonmoy Kumar Mondal ◽  
Hani Alothaid ◽  
Md. Didaruzzaman Sohel ◽  
MD Wadud ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Particle Size ◽  
Dissolution Rate ◽  
Average Particle Size ◽  
Scale Up ◽  
Average Particle ◽  
Total Drug ◽  
Residual Solvent ◽  
Dissolution Study ◽  
Drug Content

Aim: EPAS (evaporative precipitation into aqueous solution) was used in the current studies to prepare azithromycin nanosuspensions and investigate the physicochemical characteristics for the nanosuspension batches with the aim of enhancing the dissolution rate of the nanopreparation to improve bioavailability. Methods: EPAS method used in this study for preparing azithromycin nanosuspension was achieved through developing an in-house instrumentation method. Particle size distribution was measured using Zetasizer Nano S without sample dilution. Dissolved azithromycin nanosuspensions were also compared with raw azithromycin powder and commercially available products. Total drug content of nanosuspension batches were measured using an Ultra-Performance Liquid Chromatography (UPLC) system with Photodiode Array (PDA) detector while residual solvent was measured using gas chromatography (GC). Results: The average particle size of azithromycin nanosuspension was 447.2 nm and total drug content was measured to be 97.81% upon recovery. Dissolution study data showed significant increase in dissolution rate for nanosuspension batch when compared to raw azithromycin and commercial version (microsuspension). The residual solvent found for azithromycin nanosuspension is 0.000098023 mg/ mL or 98.023 ppb. Conclusion: EPAS was successfully used to prepare azithromycin nanoparticles that exhibited significantly enhanced dissolution rate. Further studies are required to scale up the process and determine long term stability of the nanoparticles.

scholarly journals Evaluation of the Effects of Filler Fineness on the Properties of an Epoxy Asphalt Mixture

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2003
Author(s):  
Wei Xu ◽  
Jintao Wei ◽  
Zhengxiong Chen ◽  
Feng Wang ◽  
Jian Zhao
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Asphalt Mixture ◽  
Average Particle ◽  
Fine Dust ◽  
Bonding Structure ◽  
Epoxy Asphalt ◽  
Mineral Powder ◽  
Marshall Stability ◽  
Mixture Sample

The type and fineness of a filler significantly affect the performance of an asphalt mixture. There is a lack of specific research on the effects of filler fineness and dust from aggregates on the properties of epoxy asphalt (EA) mixtures. The effects of aggregate dust and mineral powder on the properties of an EA mixture were evaluated. These filler were tested to determine their fineness, specific surface area and mineral composition. The effects of these fillers on the EA mastic sample and mixture were evaluated. The morphology of the EA mastic samples was analyzed using scanning electron microscopy (SEM). The effects of the fillers on the Marshall stability, tensile strength and fatigue performance of the EA mixture were evaluated. The dust from the aggregates exhibited an even particle size distribution, and its average particle size was approximately 20% of that of the mineral powder. The SEM microanalysis showed that the EA mastic sample containing relatively fine dust formed a tight and dense interfacial bonding structure with the aggregate. The EA mixture sample containing filler composed of dust from aggregate had a significantly higher strength and longer fatigue life than that of the EA sample containing filler composed of mineral powder.

scholarly journals Surface Activity of Humic Acid and Its Sub-Fractions from Forest Soil

2021 ◽  
Vol 13 (15) ◽  
pp. 8122
Author(s):  
Shijie Tian ◽  
Weiqiang Tan ◽  
Xinyuan Wang ◽  
Tingting Li ◽  
Fanhao Song ◽  
...  
Keyword(s):  
Surface Tension ◽  
Particle Size ◽  
Humic Acid ◽  
Forest Soil ◽  
Surface Activity ◽  
Self Assembly ◽  
Average Particle Size ◽  
Gaussian Model ◽  
Exponential Model ◽  
Average Particle

Surface activity of humic acid (HA) and its six sub-fractions isolated from forest soil were characterized by surface tension measurements, dynamic light scattering, and laser doppler electrophoresis. The surface tension of HA and its sub-fractions reduced from 72.4 mN·m−1 to 36.8 mN·m−1 in exponential model with the increasing concentration from 0 to 2000 mg·L−1. The critical micelle concentration (CMC) and Z-average particle size ranged from 216–1024 mg·L−1 and 108.2–186.9 nm for HA and its sub-fractions, respectively. The CMC have related with alkyl C, O-alkyl C, aromatic C, and carbonyl C (p < 0.05), respectively, and could be predicted with the multiple linear regression equation of CMC, CMC = 18896 − 6.9 × C-296 × alkyl C-331 × aromatic C-17019 × H/C + 4054 × HB/HI (p < 0.05). The maximum particle size was 5000 nm after filtered by a membrane with pore size of 450 nm, indicating HA and its sub-fractions could progressed self-assembly at pH 6.86. The aggregate sizes of number-base particle size distributions were mainly in six clusters including 2 ± 1 nm, 5 ± 2 nm, 10 ± 3 nm, 21 ± 8 nm, 40 ± 10 nm, and >50 nm analyzed by Gaussian model that maybe due to the inconsistency of the components and structures of the HA sub-fractions, requiring further study. It is significance to explore the surface activity of HA and its sub-fractions, which is helpful to clarify the environmental behavior of HA.

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