scholarly journals Determination of Particle Size Distribution of Used Black Tea Leaves by Scanning Electron Microscope

2013 ◽  
Vol 61 (1) ◽  
pp. 111-115 ◽  
Author(s):  
Mohammad Abul Hossain ◽  
Shigeru Mori
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Black Tea ◽  
Tea Leaves ◽  
Sem Images ◽  
Scanning Electron

The particle size distribution (PSD) of a particulate material is important in understanding its physical and chemical properties. Determination of PSD is essential in many physicochemical processes and production quality depends on the measurement and control of PSD. Scanning electron microscope (SEM), in addition to sieve analysis, has been used to determine the PSD of biomass materials like used black tea leaves (UBTL). Spherical, ellipsoidal and non-spherical particles of used black tea leaves were observed in SEM images. The PSD of four different sizes ranges of spherical and non spherical UBTL particles was determined from the measurement of SEM images of length wise and width wise diameters. The results enabled to determine the mean diameter or representative diameters of particles of wide size ranges. Dhaka Univ. J. Sci. 61(1): 111-115, 2013 (January) DOI: http://dx.doi.org/10.3329/dujs.v61i1.15106

scholarly journals The particle size distribution (PSD) as criteria for comparison of silver powders obtained by different methods of synthesis and by conditions of electrolysis

2018 ◽  
Vol 54 (3) ◽  
pp. 291-300
Author(s):  
Lj. Avramovic ◽  
M. Bugarin ◽  
D. Milanovic ◽  
V. Conic ◽  
M.M. Pavlovic ◽  
...  
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Chemical Processes ◽  
The Third ◽  
Methods Of Synthesis ◽  
Current Densities ◽  
Scanning Electron

Silver powders produced by both electrochemical (galvanostatic (DC) and potentiostatic (POT) regimes of electrolysis) and chemical processes were examined by scanning electron microscope, and particle size distribution (PSD) of the obtained particles was done. In the DC regime, the current densities of ?14.4 mA cm-2 for the nitrate (NIT; powder denoted with DC(NIT)) and ?13.05 mA cm-2 for the ammonium (AM; DC(AM)) electrolytes were applied. In the POT regime, the used overpotentials were ?90 mV (NIT(90)) and ?150 mV (NIT(150)) for the nitrate, and ?625 mV (AM(625)) and ?925 mV (AM(925)) for the ammonium electrolytes. Reduction with hydrazine was used for chemical synthesis (powder denoted with HYD). On the basis of SEM and PSD analysis, Ag powders were grouped into three groups. In the first group DC(AM), AM(925) and HYD powders with the (8.4?8.9 %) volume ratios were placed. In the second group were AM(625) and DC(NIT) powders with the (6.5?6.6 %) volume ratios. NIT(90) and NIT(150) powders with the volume ratios of (5.2?5.7 %) made the third group. The obtained volume ratios were correlated with the morphology of synthesized particles in order to perceive advantages and lacks of powder production via electrochemical and chemical routes.

scholarly journals FABRICATION OF 2-5 µM HYGROSCOPIC SEEDING MATERIAL FOR RAIN ENHANCEMENT PURPOSES

2021 ◽  
Vol 22 (1) ◽  
pp. 35-39
Author(s):  
Dini Harsanti ◽  
Krisna Adhitya ◽  
Safrizal Safrizal
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Size Distribution ◽  
Cloud Condensation Nuclei ◽  
Condensation Nuclei ◽  
Seeding Material ◽  
Rough Milling ◽  
Jet Milling ◽  
Scanning Electron

Abstract Hygroscopic cloud seeding, which uses giant cloud condensation nuclei (GCCN) particles with diameters between 2-5 µm, has been known to be 100 times more effective compared to those that use hygroscopic flares. Micronisation through jet milling has been recognized as the most common and ubiquitous method used to obtain particles with such a narrow size (2-5 µm) distribution. This research has successfully developed and identified 2-5 µm NaCl powders mixed with 10% cab-o-sil anticaking agent and 2 (two) times jet milling frequency as a potential GCCN (hygroscopic) seeding material. We use a combination of jet mill micronisation, rough milling with a Cross-Beather Mill, and analytical sieving to produce powders with those mentioned above (2-5 µm) size distribution. We varied the anticaking agent percentage in the mixture and the jet milling process frequency to identify which parameters would result in the 2-5 µm size distribution. We then confirmed the micronisation results particle size distribution with a particle size analyzer (PSA) and its morphology with a scanning electron microscope (SEM) machine. The materials with the 10% cab-o-sil agent mixture were confirmed to have the aforementioned size distribution from the characterization results. Intisari Penyemaian awan higroskopis menggunakan partikel giant cloud condensation nuclei (GCCN) dengan diameter 2-5 m telah diketahui 100 kali lebih efektif dibandingkan dengan yang menggunakan flare higroskopis. Mikronisasi melalui jet milling telah dikenal sebagai metode yang paling umum dan banyak digunakan untuk mendapatkan partikel dengan distribusi ukuran sempit (2-5 µm). Penelitian ini berhasil mengembangkan dan mengidentifikasi serbuk NaCl 2-5 µm yang dicampur dengan 10% anti gumpal berupa Cab-O-Sil dan frekuensi jet milling 2 (dua) kali sebagai bahan penyemaian GCCN (higroskopis) potensial. Pada penelitian ini telah digunakan kombinasi mikronisasi jet mill, penggilingan kasar dengan Cross-Beather Mill, dan ayakan analitik untuk menghasilkan serbuk dengan distribusi ukuran yang disebutkan di atas (2-5 µm). Telah divariasikan pula persentase bahan anti gumpal dalam campuran dan frekuensi proses jet milling untuk mengidentifikasi parameter yang akan menghasilkan distribusi ukuran 2-5 µm. Distribusi ukuran partikel hasil mikronisasi tersebut kemudian dikonfirmasi dengan alat analisa ukuran partikel (PSA) dan morfologinya dengan mesin scanning electron microscope (SEM). Dari hasil karakterisasi, material dengan campuran anti gumpal Cab-O-Sil sebanyak 10% dipastikan memiliki sebaran ukuran tersebut.

scholarly journals Evolución de la microestructura en aleaciones de acero inoxidable Fe-Cr preparadas por pulvimetalurgia

Respuestas ◽  
2016 ◽  
Vol 15 (2) ◽  
pp. 5-9
Author(s):  
Armando Sarmiento Santos
Keyword(s):  
Particle Size ◽  
Electron Microscope ◽  
Powder Metallurgy ◽  
Scanning Electron Microscope ◽  
Particle Size Distribution ◽  
Chromium Content ◽  
Density Variation ◽  
X Ray ◽  
Lower Porosity ◽  
Scanning Electron

Se estudia la influencia de los procesos utilizados durante las etapas de preparación de muestras por pulvimetalurgia, en algunas de las características de aleaciones inoxidables de Fe-Cr. Para ello se preparan muestras Fe-Cr con concentraciones de cromo entre 13,9 y 28,4 % en peso, se correlaciona el comportamiento de la variación de densidad de las muestras con su contenido de cromo y con los parámetros del proceso. Las muestras se someten a análisis elemental con la microsonda de rayos X acoplada al microscopio electrónico de barrido para corroborar los correspondientes contenidos de cromo. También fue observada la microestructura para las muestras con diferentes concentraciones de cromo. A partir de los análisis realizados se encontró una mayor densificación en las muestras con mayores contenidos de cromo, las cuales corresponden a una distribución de tamaño de partícula más ancha. Del estudio de la microestructura de las muestras, en función del contenido de cromo, se observa un mayor crecimiento de grano y menor porosidad en muestras con menor contenido de cromo.Palabras clave: pulvimetalurgia, aleaciones inoxidables, cromoAbstractThe influence of the processes used during the stages of sample preparation by powder metallurgy, in some of the characteristics of Fe-Cr stainless alloys, are studied. For this will prepared Fe-Cr samples with chromium concentrations between 13.9 and 28.4% by weight. The behavior of the density variation of samples with chromium content and process parameters were correlated. The samples were subjected to elemental analysis with X-ray microprobe coupled to a scanning electron microscope to confirm the relevant contents of chromium. Microstructure was also observed for samples with different chromium concentrations. From the analysis, we found a higher density in samples with higher chromium contents, which correspond to a wider particle size distribution. The study of samples microstructure, as a function of chromium content, reveals a higher grain growth and lower porosity in samples with lower chromium content. Keywords: powder metallurgy, stainless alloys, chromium

Sign in / Sign up

Export Citation Format

Share Document