Optical Particle Size Analyzer Research Articles

Experimental study of mist generated from metalworking fluids emulsions

This paper presents an experimental study of aerosol/mist formed from emulsions of metalworking fluids (MWF) under laboratory conditions. Three different commercial MWFs were investigated at three different oil-in-water emulsion concentrations, 1, 6, and 10% (v/v). The aerosol was generated by novel rotary aerosol generator at a constant rotating speed excluding heat generated by friction. In this way evaporation/condensation mechanism of aerosol generation was minimized. The emulsion was pumped at a constant flow rate. The aerosols characteristics were measured by an optical particle size analyzer. The data for particulate matter less than 2.5μm, (PM2.5), aerosol size distribution, Sauter mean diameter (SD), mass median diameter (MMD) and mass concentration are reported and discussed. Our data show that with increase of the oil concentration in the emulsion, the aerosol droplet sizes increase although the emulsions viscosity does not change significantly.

Soil property effects on wind erosion of organic soils

Abstract Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (OM > 20%) in half or more of the upper 80 cm. Forty two states have a total of 21 million ha of Histosols in the United States. These soils, when intensively cropped, are subject to wind erosion resulting in loss of crop productivity and degradation of soil, air, and water quality. Estimating wind erosion on Histosols has been determined by USDA–Natural Resources Conservation Service (NRCS) as a critical need for the Wind Erosion Prediction System (WEPS) model. WEPS has been developed to simulate wind erosion on agricultural land in the US, including soils with organic soil material surfaces. However, additional field measurements are needed to understand how soil properties vary among organic soils and to calibrate and validate estimates of wind erosion of organic soils using WEPS. Soil properties and sediment flux were measured in six soils with high organic contents located in Michigan and Florida, USA. Soil properties observed included organic matter content, particle density, dry mechanical stability, dry clod stability, wind erodible material, and geometric mean diameter of the surface aggregate distribution. A field portable wind tunnel was used to generate suspended sediment and dust from agricultural surfaces for soils ranging from 17% to 67% organic matter. The soils were tilled and rolled to provide a consolidated, friable surface. Dust emissions and saltation were measured using an isokinetic vertical slot sampler aspirated by a regulated suction source. Suspended dust was sampled using a Grimm optical particle size analyzer. Particle density of the saltation-sized material (>106 μm) was inversely related to OM content and varied from 2.41 g cm−3 for the soil with the lowest OM content to 1.61 g cm−3 for the soil with highest OM content. Wind erodible material and the geometric mean diameter of the surface soil were inversely related to dry clod stability. The effect of soil properties on sediment flux varied among flux types. Saltation flux was adequately predicted with simple linear regression models. Dry mechanical stability was the best single soil property linearly related to saltation flux. Simple linear models with soil properties as independent variables were not well correlated with PM10 E values (mass flux). A second order polynomial equation with OM as the independent variable was found to be most highly correlated with PM10 E values. These results demonstrate that variations in sediment and dust emissions can be linked to soil properties using simple models based on one or more soil properties to estimate saltation mass flux and PM10 E values from organic and organic-rich soils.

Effect of ventilation in enclosure machine system on MWF aerosol properties

In this paper the influence of ventilation air velocity on properties of metal working fluids (MWF) aerosol/mist is presented. Aerosol characteristics were monitored in the chamber as well as at the entrance of ventilation pipe by optical particle size analyzer. Aerosol was generated from 6% water emulsion of three commercial MWF. Four different velocities, less than the velocity of secondary atomization, were examined (1, 3, 6, 8 m/s). Droplets size distribution, mass concentration (mg/m3), as well as number concentration (P/cm3) were measured and analyzed. From the results obtained it may be seen that coalescence is more pronounced as the velocity increases, although the number concentration decreases, due to higher air dilution. Therefore, more droplets are in a whirling motion at higher air velocities, hence more random collisions are possible. Further analysis shows that there is one value of air velocity under which the maximum difference between the aerosol in chamber and the aerosol at the entrance of the pipe can be observed. This velocity could be named specific velocity and depends on the given aerosol properties. It could be assumed that specific velocity is conditioned by the properties of oil from which emulsion is prepared. Oil viscosity and molar mass have greatest influence on the specific velocity.

Synthesis and performance of carbon-coated Li3V2(PO4)3 cathode materials for lithium-ion batteries

The carbon-coated monoclinic Li3V2(PO4)3 (LVP/C) cathode materials can be synthesized by one-step heat treatment from a sucrose-containing precursor. Properties of the prepared composite material were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), pore size distribution and specific surface area analyzer, optical particle size analyzer and electrochemical methods. X-ray diffraction results show that LVP sample is monoclinic structure. The sample presents initial discharge capacity of 127.2 mA h/g (at 0.2 C rate), and exhibits better cycling stability (115.1 mA h/g at 30th cycle at 0.2 C rate) and better rate capability (83.1 mA h/g at 50th cycle under 6 C rate) in the voltage range of 3.0–4.3 V. In the voltage range of 3.0–4.8 V, it exhibits a initial discharge capacity of 169.1 mA h/g and good cycling stability (104.9 mA h/g at 20th cycle at 0.5 C rate).

A simple, cheap soft synthesis routine for LiFePO 4 using iron(III) raw material

An order olivine structure LiFePO 4 was synthesized with a simple rheological phase reaction (RPR) of LiOH·H 2O and FePO 4·4H 2O in the presence of PEG as a reductive agent and carbon source. A required amount of water was added to the starting materials to form the rheological precursor and decomposed at 700 °C to form the crystalline phase LiFePO 4 directly, without ball-milling, preparation of intermediates, pre-sintering and post-deposition treatment. Fine particles with an average particle size about 216 nm are examined by scanning electron microscopy (SEM) and optical particle size analyzer. An initial discharge capacity of 157 mAh g −1 was achieved for the as-prepared LiFePO 4 material with a rate of 0.1 C (17 mA g −1), what's more, this material shows excellent specific capacity, charge–discharge efficiency and cycle efficiency at high current rates, almost no capacity loss can be observed up to 40 cycles with the rate of 1, 2 and 3 C at room temperature. The simple, cheap process as well as the excellent high-rate performance makes this RPR method feasible commercially.

Measurement of intergranular stress and porosity during dynamic compaction of porous beds of cyclotetramethylene tetranitramine

The dynamic compaction of granular beds of the propellant cyclotetramethylene tetranitramine (HMX) has been investigated using a modified split Hopkinson pressure bar system. Intergranular stress and bed porosity were simultaneously measured during controlled loading. The importance of grain size was investigated by comparing conventional HMX (mean particle size ∼260μm) to microfine HMX (<5μm). Samples were radially confined and compression was predetermined using special end caps. Initial porosity was varied by hydraulically pressing the beds prior to testing. With large grains, resistance to compaction increased with the solid volume fraction. Microfine HMX behaved like low porosity conventional HMX beds in all cases. Porosity was typically reduced by 5%–10% during compaction and intergranular stresses below the yield stress were ensured. Energy dissipation to plastic flow and fracture were largely eliminated. Optical particle size analysis and electron microscopy support the experimental observations.

Sedimentation Method in Calibrating Optical Particle Counters

The use of a horizontal elutriator in calibrating optical particle counters according to aerodynamic particle size has been studied. As elutriator a ceramic component with 4800 parallel square channels with dimensions of 0.1 × 0.1 × 15.2 cm has been used. The advantage of the present method is that the particle penetration characteristic of the elutriator can be easily changed simply by varying the flow rate. The elutriator has been used in studying the properties of an optical particle size analyzer (PMS Las-X). The relationship between the equivalent aerodynamic particle size and the corresponding particle size indicated by the analyzer has been determined by using Arizona road dust particles and dioctylphthalate particles. The practical size range of the method is Dp ≥ 0.3 μm.

Optical particle size measurements of hygroscopic smokes in laboratory and field environments

Optical particle size analyzer (PSA) measurements of hygroscopic smokes are reported from experiments conducted in laboratory chambers and in field tests. Three different instruments were used: a particle sizing interferometer; a Climet (model 211); and a Particle Measurement Systems PSA (model CSASP-100-HC). Field measurements were made in relative humidity conditions ranging between 65 and 97%. The results indicate that the size distributions are at least bimodal-not log-normal-and that mean particle diameter does not appear to increase with increasing relative humidity.