Relating in situ hydraulic conductivity, particle size and relative density of superficial deposits in a heterogeneous catchment

Ciprofloxacin hydrochloride loaded Eudragit RS100 nanoparticles were prepared by using w/o/w emulsification (multiple emulsification) solvent evaporation followed by drying of nanoparticles at 50°C. The nanoparticles were further incorporated into the pH-triggered in situ gel forming system which was prepared using Carbopol 940 in combination with HPMC as viscosifying agent. The developed nanoparticles was evaluated for particle size, zeta potential value and loading efficiency; nanoparticle incorporated in situ gelling system was evaluated for pH, clarity, gelling strength, rheological studies, in-vitro release studies and ex-vivo precorneal permeation studies. The nanopaticle showed the mean particle size varying between 263.5nm - 325.9 nm with the mean zeta potential value of -5.91 mV to -8.13 mV and drug loading capacity varied individually between 72.50% to 98.70% w/w. The formulation was clear with no suspended particles, showed good gelling properties. The gelling was quick and remained for longer time period. The developed formulation was therapeutically efficacious, stable and non-irritant. It provided the sustained release of drug over a period of 8-10 hours.

Download Full-text

Field testing of general ventilation filtration devices and systems for in situ removal efficiency by particle size and resistance to airflow

10.3403/30211681 ◽

2013 ◽

Keyword(s):

Particle Size ◽

Removal Efficiency ◽

Field Testing

Download Full-text

Relationship between the Hydraulic Conductivity Function and the Particle-Size Distribution

Soil Science Society of America Journal ◽

10.2136/sssaj2003.0373 ◽

2003 ◽

Vol 67 (1) ◽

pp. 373

Author(s):

Lalit M. Arya ◽

Feike J. Leij ◽

Peter J. Shouse ◽

Martinus Th. van Genuchten

Keyword(s):

Particle Size ◽

Hydraulic Conductivity ◽

Particle Size Distribution ◽

Size Distribution ◽

Conductivity Function

Download Full-text

Effect of particle size on in-situ desulfurization for oxy-fuel CFBC

Fuel ◽

10.1016/j.fuel.2021.120270 ◽

2021 ◽

Vol 291 ◽

pp. 120270

Author(s):

Seo Yeong Kang ◽

Su Been Seo ◽

Eun Sol Go ◽

Hyung Woo Kim ◽

Sang In Keel ◽

...

Keyword(s):

Particle Size ◽

Effect Of Particle Size

Download Full-text

Improvement of mechanical properties of HfB2-based composites by incorporating in situ SiC reinforcement through pressureless sintering

Scientific Reports ◽

10.1038/s41598-021-88566-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

S. Ghadami ◽

E. Taheri-Nassaj ◽

H. R. Baharvandi ◽

F. Ghadami

Keyword(s):

Mechanical Properties ◽

Thermal Conductivity ◽

Relative Density ◽

Pressureless Sintering ◽

Sintering Process ◽

Vacuum Atmosphere ◽

Sic Reinforcement ◽

Microstructural Studies ◽

Composite Samples

AbstractHfB2, Si, and activated carbon powders were selected to fabricate 0–30 vol% SiC reinforced HfB2-based composite. Pressureless sintering process was performed at 2050 °C for 4 h under a vacuum atmosphere. Microstructural studies revealed that in situ SiC reinforcement was formed and distributed in the composite according to the following reaction: Si + C = SiC. A maximum relative density of 98% was measured for the 20 vol% SiC containing HfB2 composite. Mechanical investigations showed that the hardness and the fracture toughness of these composites were increased and reached up to 21.2 GPa for HfB2-30 vol% SiC and 4.9 MPa.m1/2 for HfB2-20 vol% SiC, respectively. Results showed that alpha-SiC reinforcements were created jagged, irregular, and elongated in shape which were in situ formed between HfB2 grains and filled the porosities. Formation of alpha-SiC contributed to improving the relative density and mechanical properties of the composite samples. By increasing SiC content, an enhanced trend of thermal conductivity was observed as well as a reduced trend for electrical conductivity.

Download Full-text

Effects of processing, moisture, and storage length on the fermentation profile, particle size, and ruminal disappearance of reconstituted corn grain

Journal of Animal Science ◽

10.1093/jas/skaa332 ◽

2020 ◽

Vol 98 (11) ◽

Author(s):

Ana L M Gomes ◽

Antonio V I Bueno ◽

Fernando A Jacovaci ◽

Guilherme Donadel ◽

Luiz F Ferraretto ◽

...

Keyword(s):

Particle Size ◽

Lactic Acid ◽

Butyric Acid ◽

Hammer Mill ◽

Moisture Concentration ◽

Fermentation Profile ◽

And Storage ◽

Ground Corn ◽

Corn Grain

Abstract Our objective was to examine the effects of processing, moisture, and anaerobic storage length of reconstituted corn grain (RCG) on the fermentation profile, geometric mean particle size (GMPS), and ruminal dry matter disappearance (DMD). Dry corn kernels were ground (hammer mill, 5-mm screen) or rolled, then rehydrated to 30%, 35%, or 40% moisture, and stored for 0, 14, 30, 60, 90, 120, or 180 d in laboratory silos. Rolled corn had an increased GMPS compared with ground corn (2.24 and 1.13 mm, respectively, at ensiling). However, there was a trend for an interaction between processing and moisture concentration to affect particle size, with GMPS increasing with increased moisture concentration, especially in ground corn. Longer storage periods also slightly increased GMPS. Processing, moisture, and storage length interacted to affect the fermentation pattern (two- or three-way interactions). Overall, pH decreased, whereas lactic acid, acetic acid, ethanol, and NH3-N increased with storage length. RCG with 30% moisture had less lactic acid than corn with 35% and 40% moisture, indicating that fermentation might have been curtailed and also due to the clostridial fermentation that converts lactic acid to butyric acid. Ensiling reconstituted ground corn with 30% of moisture led to greater concentrations of ethanol and butyric acid, resulting in greater DM loss than grain rehydrated to 35% or 40% of moisture. Ammonia-N and in situ ruminal DMD were highest for reconstituted ground corn with 35% or 40% of moisture, mainly after 60 d of storage. Therefore, longer storage periods and greater moisture contents did not offset the negative effect of greater particle size on the in situ ruminal DMD of rolled RCG. Nonetheless, RCG should be ensiled with more than 30% moisture and stored for at least 2 mo to improve the ruminal DMD and reduce the formation of ethanol and butyric acid.

Download Full-text

In Situ Synthesis of Core-Shell-Structured SiCp Reinforcements in Aluminium Matrix Composites by Powder Metallurgy

Metals ◽

10.3390/met11081201 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1201

Author(s):

Xinghua Ji ◽

Cheng Zhang ◽

Shufeng Li

Keyword(s):

Particle Size ◽

Powder Metallurgy ◽

Shell Structure ◽

Ex Situ ◽

Aluminium Matrix ◽

Core Shell ◽

Matrix Composites ◽

Aluminium Matrix Composites ◽

Core Shell Structure

SiCp reinforced aluminium matrix composites (AMCs), which are widely used in the aerospace, automotive, and electronic packaging fields along with others, are usually prepared by ex situ techniques. However, interfacial contamination and poor wettability of the ex situ techniques make further improvement in their comprehensive performance difficult. In this paper, SiCp reinforced AMCs with theoretical volume fractions of 15, 20, and 30% are prepared by powder metallurgy and in situ reaction via an Al-Si-C system. Moreover, a combined method of external addition and an in situ method is used to investigate the synergistic effect of ex situ and in situ SiCp on AMCs. SiC particles can be formed by an indirect reaction: 4Al + 3C → Al4C3 and Al4C3 + 3Si → 3SiC + 4Al. This reaction is mainly through the diffusion of Si, in which Si diffuses around Al4C3 and then reacts with Al4C3 to form SiCp. The in situ SiC particles have a smooth boundary, and the particle size is approximately 1–3 μm. A core-shell structure having good bonding with an aluminium matrix was generated, which consists of an ex situ SiC core and an in situ SiC shell with a thickness of 1–5 μm. The yield strength and ultimate tensile strength of in situ SiCp reinforced AMCs can be significantly increased with a constant ductility by adding 5% ex situ SiCp for Al-28Si-7C. The graphite particle size has a significant effect on the properties of the alloy. A criterion to determine whether Al4C3 is a complete reaction is achieved, and the forming mechanism of the core-shell structure is analysed.

Download Full-text

Laboratory and In Situ Determination of Hydraulic Conductivity and Their Validity in Transient Seepage Analysis

Water ◽

10.3390/w13081131 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1131

Author(s):

Soonkie Nam ◽

Marte Gutierrez ◽

Panayiotis Diplas ◽

John Petrie

Keyword(s):

Hydraulic Conductivity ◽

Field Measurements ◽

Natural Soil ◽

In Situ Tests ◽

Seepage Analysis ◽

Soil Deposits ◽

Seepage Modeling ◽

Sample Disturbance

This paper critically compares the use of laboratory tests against in situ tests combined with numerical seepage modeling to determine the hydraulic conductivity of natural soil deposits. Laboratory determination of hydraulic conductivity used the constant head permeability and oedometer tests on undisturbed Shelby tube and block soil samples. The auger hole method and Guelph permeameter tests were performed in the field. Groundwater table elevations in natural soil deposits with different hydraulic conductivity values were predicted using finite element seepage modeling and compared with field measurements to assess the various test results. Hydraulic conductivity values obtained by the auger hole method provide predictions that best match the groundwater table’s observed location at the field site. This observation indicates that hydraulic conductivity determined by the in situ test represents the actual conditions in the field better than that determined in a laboratory setting. The differences between the laboratory and in situ hydraulic conductivity values can be attributed to factors such as sample disturbance, soil anisotropy, fissures and cracks, and soil structure in addition to the conceptual and procedural differences in testing methods and effects of sample size.

Download Full-text

Simplified estimation of unsaturated soil hydraulic conductivity using bulk electrical conductivity and particle size distribution

Soil Research ◽

10.1071/sr12158 ◽

2013 ◽

Vol 51 (1) ◽

pp. 23 ◽

Cited By ~ 8

Author(s):

Mohammad Reza Neyshabouri ◽

Mehdi Rahmati ◽

Claude Doussan ◽

Boshra Behroozinezhad

Keyword(s):

Electrical Conductivity ◽

Particle Size ◽

Hydraulic Conductivity ◽

Particle Size Distribution ◽

Size Distribution ◽

Unsaturated Soil ◽

Soil Core ◽

Soil Hydraulic Conductivity ◽

Core Samples ◽

Soil Hydraulic

Unsaturated soil hydraulic conductivity K is a fundamental transfer property of soil but its measurement is costly, difficult, and time-consuming due to its large variations with water content (θ) or matric potential (h). Recently, C. Doussan and S. Ruy proposed a method/model using measurements of the electrical conductivity of soil core samples to predict K(h). This method requires the measurement or the setting of a range of matric potentials h in the core samples—a possible lengthy process requiring specialised devices. To avoid h estimation, we propose to simplify that method by introducing the particle-size distribution (PSD) of the soil as a proxy for soil pore diameters and matric potentials, with the Arya and Paris (AP) model. Tests of this simplified model (SM) with laboratory data on a broad range of soils and using the AP model with available, previously defined parameters showed that the accuracy was lower for the SM than for the original model (DR) in predicting K (RMSE of logK = 1.10 for SM v. 0.30 for DR; K in m s–1). However, accuracy was increased for SM when considering coarse- and medium-textured soils only (RMSE of logK = 0.61 for SM v. 0.26 for DR). Further tests with 51 soils from the UNSODA database and our own measurements, with estimated electrical properties, confirmed good agreement of the SM for coarse–medium-textured soils (<35–40% clay). For these textures, the SM also performed well compared with the van Genuchten–Mualem model. Error analysis of SM results and fitting of the AP parameter showed that most of the error for fine-textured soils came from poorer adequacy of the AP model’s previously defined parameters for defining the water retention curve, whereas this was much less so for coarse-textured soils. The SM, using readily accessible soil data, could be a relatively straightforward way to estimate, in situ or in the laboratory, K(h) for coarse–medium-textured soils. This requires, however, a prior check of the predictive efficacy of the AP model for the specific soil investigated, in particular for fine-textured/structured soils and when using previously defined AP parameters.

Download Full-text

Mechanical Response of Porous Copper Manufactured by Lost Carbonate Sintering Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.539-543.1863 ◽

2007 ◽

Vol 539-543 ◽

pp. 1863-1867 ◽

Cited By ~ 6

Author(s):

X.F. Tao ◽

Li Ping Zhang ◽

Y.Y. Zhao

Keyword(s):

Particle Size ◽

Flexural Strength ◽

Relative Density ◽

Mechanical Response ◽

Compaction Pressure ◽

Absorption Capacity ◽

Energy Absorption Capacity ◽

Three Point Bending ◽

Porous Copper ◽

The Impact

This paper investigated the mechanical response of porous copper manufactured by LCS under three-point bending and Charpy impact conditions. The effects of the compaction pressure and K2CO3 particle size used in producing the porous copper samples and the relative density of the samples were studied. The apparent modulus, flexural strength and energy absorption capacity in three-point bending tests increased exponentially with increasing relative density. The impact strength was not markedly sensitive to relative density and had values within 7 – 9 kJ/m2 for the relative densities in the range 0.17 – 0.31. The amount of energy absorbed by a porous copper sample in the impact test was much higher than that absorbed in the three-point bending test, impling that loading strain rate had a significant effect on the deformation mechanisms. Increasing compaction pressure and increasing K2CO3 particle size resulted in significant increases in the flexural strength and the bending energy absorption capacity, both owing to the reduced sintering defects.

Download Full-text