laser diffraction analysis
ian treviranus, product line manager for horiba scientific (urltoken), discusses fundamental principles and practical considerations of laser diffraction for particle size analysis .
within our laser diffraction systems the primary physical diffraction set - up is realised deploying a parallel laser beam. this yields the purest optical alignment for analysis of extended special arrangements of particle collectives which allows for size characterization beyond limiting assumptions and constraint .
konert m, vandenberghe jef (1997) comparison of laser grain size analysis with pipette and sieve analysis: a solution for the underestimation of the clay fraction. sedimentology 44: 523–535 .
laser diffraction is so popularly and extensively used because it offers a number of advantages. these advantages include :
laser diffraction uses mie theory of light scattering to calculate the particle size distribution, assuming a volume equivalent sphere model .
laser diffraction is an important technique for measuring particle size. here we offer a range of facts about this technique :
the helium gas in the laser tube provides the pumping medium to attain the necessary population inversion for laser action .
eshel g, levy gj, mingelgrin u, singer mj (2004) critical evaluation of the use of laser diffraction for particle - size distribution analysis. soil sci soc am j 68: 736–743 .
pieri l, bittelli m, pisa pr (2006) laser diffraction, transmission electron microscopy and image analysis to evaluate a bimodal gaussian model for particle size distribution in soils. geoderma. 135: 118–132 .
a sophisticated method for determining particle size, laser diffraction is widely used and offers distinct advantages that are beneficial for many industries .
. today, laser diffraction analyzers go beyond simple diffraction effects. general approaches are now based on the mie theory and the measurement of scattering intensity over a wide scattering angular range is employed. additionally, non - laser light sources are often used to complement the main laser source to gain additional characteristic information about submicron - size particles .
diffraction is also known as
edge diffraction
as that is where it occurs. refraction occurs as light changes angle traveling throught the particle .
... two types of international standard methods for laser diffraction have established in dry and wet forms (iso 13320 - 1, 1999). a manufacturer of laser diffraction also recommends users select the appropriate dispersion method between dry and wet dispersion analysis (kippax, 2005). one of the key points for laser diffraction particle sizing is that it is important to present well dispersed particles, which should be introduced to the sample cell at a suitable concentration with minimal sample bias... .
isotope analysis can help you identify important relationships between hydrocarbons and their sources. we offer high - precision isotopic analysis of oils, gases, kerogens, waters, and a variety of other liquids .
miller ba, schaetzl rj (2012) precision of soil particle size analysis using laser diffractometry. soil science society of america journal. 76 (5): 1719–1727 .
by laser diffraction analysis it is possible to measure particles sizes between 0. 02 and 2000 µm. the sample is dispersed in either air or a suitable liquid media. the laser passes through the dispersion media and is diffracted by the particles. the diffraction light pattern (he - ne laser) is dependent on the particle size. the laser diffraction pattern is measured and correlated to the particle size distribution based on fraunhofer or mie theory. the use of mie theory presupposes knowledge of the light refractive index of the particles and the dispersion media and the imaginary part of the refractive index of the particles. particle analytical can determine these refractive index parameters .
understanding the basic principles of laser diffraction is essential for successful method development. laser diffraction is an ensemble particle - sizing technique, which means it provides a result for the whole sample, rather than building up distributions from data for individual particles, in the way that, for example, image analysis or microscopy does. particles illuminated in a collimated laser - beam scatter light over a range of angles. large particles generate a high scattering intensity at relatively narrow angles to the incident beam, while smaller particles produce a lower intensity signal but at much wider angles. using an array of detectors, laser - diffraction analyzers record the pattern of scattered light produced by the sample .
laser diffraction is a widely used particle sizing technique for materials ranging from hundreds of nanometers up to several millimeters in size. the main reasons for its success are :
find the best system configuration for particle size distribution and particle shape analysis according to your laboratory or process application .
gee gw, bauder jw (1979) particle - size analysis by hydrometer - simplified method for routine textural analysis and a sensitivity test of measurement parameters. soil sci soc am j. 43 (5): 1004–1007 .
method development involves addressing the wider set of practical issues that flow from this underlying explanation of the basic principles of operation. united states pharmacopeia (usp) general chapter < 429 > states that laser diffraction involves the measurement of
a representative sample, dispersed at an adequate concentration in a suitable liquid or gas
( 2). this statement neatly highlights three crucial aspects of laser - diffraction analysis: sampling, dispersion, and measurement conditions .
laser diffraction is used for determination of particle size distribution. determination of particle size distribution and understanding how it affects your products and processes can be critical to the success of drug development, as it has large impact on reactivity, dissolution rate, flowability etc. the particle size distribution measured by laser diffraction can further be used for :
wang wp, liu jl, zhang jb, li xp, cheng yn, xin ww, et al. (2013) evaluation of laser diffraction analysis of particle size distribution of typical soils in china and comparison with the sieve - pipette method. soil sci 178: 194–204 .
sample measured – this technique allows for the whole of the sample to be measured. as the sample passes through the laser beam, diffraction is measured for all particles .
ryzak m, bieganowski a (2011) methodological aspects of determining soil particle - size distribution using the laser diffraction method. j plant nutr soil sci. 174: 624–633 .
the carbon dioxide laser finds many applications in industry, particularly for welding and cutting .
our express lab services provide rapid processing of cuttings samples for source - rock analysis (sra), x - ray diffraction (xrd), and x - ray fluorescence (xrf) to quantify key formation characteristics .
was larger when many bins had small differences, as in the ldm analysis which provided a psd with 117 bins. the
articles have been published that purport to demonstrate the difficulties and problems of laser diffraction without any mention that these apparent issues are inherent in all particle sizing techniques. further, no reference has been made to the advantages that laser diffraction offers in terms of repeatability, ease of verification and speed of measurement. this article sets out to redress... [ show full abstract ]
the proven helos laser diffraction series offers a powerful technology for particle size analysis of powders, granules, suspensions, emulsions, sprays and other particulate systems from below 0. 1 µm to 8, 750 µm. a great variety of dispersing and dosing units provides a flexible adaptation to myriads of industrial and research applications .
the method is founded on the fact that the angle of diffraction is inversely proportional to particle size .
the most common and inexpensive gas laser, the helium - neon laser is usually constructed to operate in the red at 632. 8 nm. it can also be constructed to produce laser action in the green at 543. 5 nm and in the infrared at 1523 nm .
gee gw, bauder jw (1986) particle - size analysis. in: klute a. (ed .) methods of soil analysis, part 1. 2nd edn. agron. monogr. 9. asa and sssa, madison, wi, pp 383–411 .
the la - 300 uses mie scattering (laser diffraction) to measure particle size of suspensions. the speed and ease - of - use of this technique makes it the most popular for many applications .
the la - 960 particle size analyzer represents the tenth generation laser diffraction instrument designed by horiba. hundreds of refinements to the basic design have been included to improve performance and usability. these refinements include :
bah ar, kravchuk o, kirchhof g (2009) fitting performance of particle - size distribution models on data derived by conventional and laser diffraction techniques. soil sci soc am j 73: 1101–1107 .
laser diffraction measurements capture information about particle size distribution by measuring scattering intensity as a function of the scattering angle, wavelength and polarization of light based on applicable scattering models. this is an absolute method that doesn’t require calibration. laser diffraction offers a number of advantages, including ease - of - use, fast operation, high reproducibility and broad dynamic size range—spanning almost five orders of magnitude, from nanometers to millimeters .
at the very heart of the laser diffraction technique is the relationship between light and surfaces (which can be freely interchanged with
particle
for our purposes). when light strikes a surface it is either
our full range of sampling and analysis services can help you address your challenges in conventional, unconventional, deepwater, and other types of plays .
... traditionally, and quite commonly still today, the determination of the product quality is carried out by off - line measurement after the process. various techniques, such as sieve analysis (26), laser diffraction (27, 28), and image analysis (29) (30) (31), are available for off - line particle size distribution measurement. recently, also spatial filtering technique (sft) has been utilized for particle size determination (32)... .
... if these properties were less easy to determine, it is unlikely that laser diffraction would ever have achieved such widespread application in the pharmaceutical industry, and the incorrect selection of optical properties is largely inexcusable. it should, however, be noted that the use of incorrect optical properties could never account for some of the large differences reported between laser diffraction and other techniques (as much as two to three orders of magnitude in some cases [ 2 ]). the errors observed are much more likely to be a result of poor sample preparation or the incorrect selection of the range lens within the laser - diffraction system... .
the la - 960 uses mie scattering (laser diffraction) to measure particle size of suspensions or dry powders. the speed and ease - of - use of this technique makes it the popular choice for most applications .
dry powders – even dry powders can be measured through the technique of laser diffraction. although this may result in a poorer level of dispersion than if a liquid dispersing medium was used, it is an advance that dry powders can be directly measured. in combination with a suspension analysis, it can support the assessment of the amount of agglomerated material in a dry state .
over the past two decades, laser diffraction has replaced conventional methods, such as sieving and sedimentation to size particles smaller than a few millimeters, and has replaced optical and electron microscopy for larger particles (> 50 µm) .
we develop, manufacture, sell and support an innovative range of best instruments for particle size and shape analysis in laboratory and process applications for customers worldwide .
the proven helos series – with its classical laser diffraction set - up deploying a parallel beam – offers a powerful technology for particle size analysis of powders, granules, suspensions, emulsions, sprays and numerous other disperse systems from below 0. 1 µm to 8, 750 µm. a great variety of dispersing and dosing units provides a flexible adaptation to myriads of industrial and research applications .
] is widely used in studies involving forecasting of biotic populations and system reliability analysis. when used to depict soil psd, the model is modified as follows :
sławinski c, walczak tr, skierucha w (2006) error analysis of water conductivity coefficient measurement by instantaneous profiles method. int agrophys. 20: 55–61 .
as a technique of particle size analysis, laser diffraction is widely used and has many advantages. it offers a high level of precision, a fast speed of response, high potential for the repetition of results and a wide measurable particle diameter range. particle size analysers offer a sophisticated way of measuring particle size and enable incredible insight and understanding of the particles that make up materials used in a range of industries .
the instrument consists of a laser (as a source of coherent intense light that has a fixed wavelength), a detector (typically an array of photo sensitive silicon diodes) and a means of passing the sample through a laser beam .
laser diffraction measures particle size distributions by measuring the angular variation in intensity of light scattered as a laser beam passes through a dispersed particulate sample. large particles scatter light at small angles relative to the laser beam and small particles scatter light at large angles, as illustrated below. the angular scattering intensity data is then analyzed to calculate the size of the particles responsible for creating the scattering pattern, using the mie theory of light scattering. the particle size is reported as a volume equivalent sphere diameter .
flexibility – laser diffraction offers new possibilities for measuring materials. it is even possible to measure the paint that is sprayed from a nozzle in a paint booth. the pharmaceutical and agricultural industries are two of the many industries that have benefited greatly from such advances .
citation: weipeng w, jianli l, bingzi z, jiabao z, xiaopeng l, yifan y (2015) critical evaluation of particle size distribution models using soil data obtained with a laser diffraction method. plos one 10 (4): e0125048. urltoken
the carbon dioxide gas laser is capable of continuous output powers above 10 kilowatts. it is also capable of extremely high power pulse operation. it exhibits laser action at several infrared frequencies but none in the visible. operating in a manner similar to the helium - neon laser, it employs an electric discharge for pumping, using a percentage of nitrogen gas as a pumping gas .
our global network of industry - leading laboratories is staffed with knowledgeable engineering and geoscience professionals to provide a comprehensive evaluation of your reservoir rock and fluids. services include routine and special core analysis; geochemical analysis of rock and fluid samples; geomechanics studies; and evaluations to support the development of any asset, from conventional to unconventional, heavy oil, and deepwater resources .
it is well known that laser diffraction systems provide rapid, accurate, and precise measurement of particle size distributions for a wide range of applications. however, optimum results depend on the development of sops that take into account the method of sample collection and dispersion within the instrument .
the microtrac s3500 is the first particle size analyzer that uses three precisely placed red laser diodes to accurately characterize particles like never before. the patented tri - laser system provides accurate, reliable and repeatable particle size analysis for a diverse range of applications by utilizing the proven theory of mie compensation for spherical particles and the proprietary principle of modified mie calculations for non - spherical particles. the s3500 measures particle size from 0. 02 to 2800 microns .
weatherford laboratories has the experience and technology to help you evaluate your sidewall cores and whole cores. our routine core analysis services include porosity, permeability, and grain density, and more .
rodos is the original by the inventor of dry dispersion. with this breakthrough innovation, sympatec has opened up dry applications to particle measurement technology – as early as 1982. since then, it has been possible to dry measure powders, fibres and granules appropriate to the product, with both laser diffraction and dynamic image analysis. no other method of dispersing is anywhere near as powerful or achieves such an efficient as well as gentle dispersion from the submicron to millimetre range .
measurement quality is all about the analyzer itself: quality of components, engineering refinement, and a fundamental design which reflects basic principles. the core technologies are all mature, but as with many things higher quality leads to superior performance. a typical laser diffraction optical system will include :
buurman p, pape t, reijneveld ja, de jong f, van gelder e (2001) laser - diffraction and pipette - method grain sizing of dutch sediments: correlations for fine fractions of marine, fluvial, and loess samples. neth j geosci. 80: 49–57 .
the co 2 laser is the most efficient laser, capable of operating at more than 30% efficiency. that' s a lot more efficient than an ordinary incandescent light bulb at producing visible light (about 90% of the output of a lightbulb filament is invisible) .
so how does laser diffraction work? at its very most basic, laser diffraction is about the relationship between particle size and the angle and intensity of scattered light. light scatters more intensely and at smaller angles off of large particles than small particles. every analyzer, from the very first commercial prototype to the state of the art la - 960 utilizes this principle. in fact, the analyzer itself does not measure particle size - - it measures the angle and intensity of light scattered from the particles in your sample. that information is then passed to an algorithm designed to use mie scattering theory which transforms the scattered light data into particle size information .
conceived and designed the experiments: ljl wwp. performed the experiments: wwp. analyzed the data: wwp yyf lxp. contributed reagents / materials / analysis tools: ljl zbz zjb. wrote the paper: wwp ljl .
mytos integrates the core particle size technologies of helos laser diffraction and rodos dry dispersion in a single robust body: a process - proven laser diffraction sensor for dry powders ranging from 0. 25 μm to 3, 500 μm. in combination with the sampling system twister a complete in - line integration into the processing pipe is realised. alternatively, mytos may be operated on - line either with twister, mixer, l - probes or existing sampling solutions. integrated at - line operation in automated lab environments is succeeded with vibratory feeder vibri. mytis is first choice for granules or fragile particles for a size range from 0. 5 to 3, 500 μm .
arriaga fj, lowery b, mays md (2006) a fast method for determining soil particle size distribution using a laser instrument. soil sci 171: 663–674 .
light scattering has long been used to investigate the size of various objects. gustav mie (he of the mie scattering theory) studied gold nanoparticles like those in the image below as part of his doctoral thesis. previously confined to custom - built setups in labs, several innovations took laser diffraction from the darkroom to research labs and production floors across the world .
both the hardware and software required to make a particle size measurement have gone through many revisions in order to improve accuracy, precision, reliability, and ease of use. the la - 960 represents the tenth generation of horiba laser diffraction analyzers; each different and better than the last. read on to discover what important factors go into making this measurement routine and trustworthy .
the laser diffraction instrument applied by particle analytical (malvern mastersizer 2000 and 3000) has a flow - through cell for dispersion of particles in liquid media or a dry dispenser for dispersion of particles in air. wet dispersion presupposes that the particles are insoluble in the liquid. therefore method development is required. we typically offer either a simple non - gmp suitability screening or a full length gmp method development .
for particles smaller than 20 microns refracted light becomes increasingly important to calculate an accurate particle size. the scattered light is at relatively low intensity and wide angle for these smaller particles. the use of a refractive index and the mie scattering theory directly affects accuracy in this size range. all horiba laser diffraction analyzers use the mie scattering solution by default and allow the user to input custom refractive index values .
the argon ion laser can be operated as a continuous gas laser at about 25 different wavelengths in the visible between 408. 9 and 686. 1nm, but is best known for its most efficient transitions in the green at 488 nm and 514. 5 nm. operating at much higher powers than the helium - neon gas laser, it is not uncommon to achieve 30 to 100 watts of continuous power using several transitions. this output is produced in a hot plasma and takes extremely high power, typically 9 to 12 kw, so these are large and expensive devices .
for particles larger than a certain size the vast majority of light is scattered by diffraction. the scattered light is at relatively high intensity and low angle for these larger particles. the
certain size
is determined as a multiple of the wavelength of light used for the measurement and typically approximated at 20 microns. particles larger than this size communicate useful size information through diffraction and not refraction. this means the measurement will not benefit from the use of a refractive index to accurately interpret refracted light .
funding: this study was funded by the national basic research program of china (973 program no. 2011cb100506) —ljl; national natural science foundation of china (contract no. 41171179) —ljl. the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript .
a simplified layout of the la - 960 optical bench. 1: red wavelength laser diode for larger particles, 2: blue led for smaller particles, 3: low angle detectors for larger particles, 4: side and back angle detector arrays and smaller particles .
some industrial particles are non - spherical, but the scattering effects from the corners and edges of these particles are smoothed out due to the tumbling and rotational motion of sample circulation during measurement. this allows for the application of either the mie or fraunhofer theory to systems with one parameter: diameter. this method yields only apparent values, and it’s important to realize the
size
obtained from most particle sizing technologies (laser diffraction included) may differ from the real dimension. to date, spherical modeling is the only feasible choice for commercial instruments designed for sizing a wide range of samples, regardless of real particle shape .
in previous work, the relative performance of various methods used to characterize the particle size distribution of powders composed of fine irregularly shaped particles was assessed. it was found that methods employing fraunhofer diffraction theory were inferior with respect to particle counting methods. furthermore, calculated particle size distributions varied considerably between... [ show full abstract ]
helium - neon lasers are common in the introductory physics laboratories, but they can still be dangerous! according to garmire, an unfocused 1 - mw hene laser has a brightness equal to sunshine on a clear day (0. 1 watt / cm 2) and is just as dangerous to stare at directly .
modeling the size distribution of soil particles to obtain a continuous particle size distribution (psd) curves is useful for understanding essential soil properties such as pore distribution, water retention, hydraulic conductivity, and thermal and adsorption properties [ 1 – 4 ]. however, conventional psd analysis captures only a limited number of particle mass fractions. therefore, to be able to use these discrete experimental psd data to estimate other soil properties, many researchers have used parametric functions to extend the limited scope of psd data .
in this article, deborah huck, phd, product technical specialist, morphological imaging systems; paul kippax, phd, product group manager, micrometrics; anne virden, phd, product technical specialist, diffraction, all of malvern instruments, and janne raula, phd, senior research associate; and professor esko kauppinen, phd, teicos pharma, inc (espoo, finland), explore the value and... [ show full abstract ]
in the present study, ph was used to identify outliers. when a set of subsample pairs had a cbd exceeding 1 sd plus the mean cbd of all samples, the precision or repeatability of the psd results were considered insufficient for this type of analysis. in these cases, additional subsamples were measured using the same procedure as for the previous subsamples until every sample had a pair of subsamples with a cbd less than the ph, which meant that some samples had to undergo more than two analyses to obtain an eligible cbd. the samples chosen for additional measurements were only those that continued to have a cbd greater than ph. for those samples which had been measured several times, the mean of the two subsample values with the least cbd was used to represent the psd for each sample .
particle size distribution is a fundamental property of any sediment or soil, and particle size determination can provide important clues to sediment provenance. for forensic work, the particle size distribution of sometimes very small samples requires precise determination using a rapid and reliable method with a high resolution. a protocol has been developed using a coulter™ ls230 laser granulometer, which can analyse particles in the size range 0. 04 μm–2000μm. the technique is essentially non - destructive, permitting the recovery of critical samples, and has been demonstrated to have high precision for a range of soils, sediments and powders of interest in forensic investigations .
few comparisons have been performed of the fitting performance of psd functions based on ldm data sets. furthermore, the effect of texture on psd model performance has not been fully investigated. therefore, the objectives of this study were to (1) use a variety of models with different underlying assumptions to test the fit of varying psd functions to laser - derived psd of soils from across china, and (2) to determine whether soil texture significantly affects model performance. three statistical indices were used to define the best models: the adjusted root - mean - square error (rmse), the adjusted r 2, and akaike’s information criterion (aic) .
aic analysis of models for soils of different clay, silt, and sand contents revealed that the performance of a psd model can be affected by soil texture. results indicated that fred3, mlog3, and four lognormal models (logn2 onlg3, orlg3, and shca3) performed consistently well for all kinds of soil texture in this study (fig 8). the fred4 model had the best fit overall, accounting for most of the smallest aic values for all soils with different textures, except for sand and loamy sand soils. other studies have previously established that fred4 is highly suitable for modeling all soil texture classes [ 26, 8, 9 ]. the difference in the present results with fred4, i. e. , the finding that it did not perform well for all soil classes, was probably related to the fact that the ldm underestimated the clay fraction. ande4 performed well for loam and sandy loam soils. jaky1, logl2, the two logistic models (logi2 and logi3), and the three van genuchten models (vanh2, vanz2, and vanz3) showed poorer performance for most texture classes. gomp4 also performed poorly for most soil types; however, for sand and loamy sand, it achieved the second most suitable fit with the psd data, after shca3. logi4 seemed to be more appropriate for silty loam, clay, clay loam, loam, and silty clay loam. the performance of vang4 was only relatively better in silty loam, clay, clay loam, sand, and sandy loam soils .
dispersion describes the behaviour of clay particles separating from one other in a moist soil. dispersion can cause soil aggregates to breakdown and the dispersed clay to clog soil pores. structural decline and
clays particles are small in size (less than 0. 002 mm) but have a very large surface area. the surface area of all clays is negatively charged. this is because of the complex arrangement of elements (e. g. aluminium, oxygen, silicon) that make up the clay structure. positive ions (cations such as calcium, ca
) present in the soil are electrostatically attracted to the negative clay surface and neutralise the charge in the clay. as all the negative charges on the clay are neutralised, a layer of positive charge surrounds the clay particle. this layer of positive charge is also known as a' shell' .
cations floating around in the soil solution as salts, also affect the width of the shell. cations' attached' to the clay particle diffuse away from the surface of the clay until the concentration of cations is equal to the concentration of cations in the soil solution. thus, the saltier the soil solution, the thinner the layer of positive charge surrounding the clay particle .
like charges repel one another, however, this can be overcome by close distance nuclear attraction, called van der waal' s forces. if the shell is thick, the clay particles are going to have trouble coming close enough together for the van der waals' forces to act and for the particles to flocculate. they will tend to remain as separate (colloidal) entities – and the clay will be dispersed .
if the shell is thin, the particles can come close together for attractive van der waal' s forces to take hold and for the clay particles to flocculate .
are typically highly dispersive for the reasons outline above. sodic soils have a high concentration of exchangeable na
, creating a thick layer of positive charge that may prevent clay particles from flocculating .
the cations ‘attached’ to the clay particle are exchangeable with other cations in the soil solution. which cations ‘attach’ to the clay depends on the concentration and physical size of the cations .
the following two videos illustrate dispersion when susceptible soil aggregates are immersed in water .
the video shows two aggregates of soil immersed in water. both aggregates slake on immersion. however, as time progresses the right hand aggregate disperses completely and all that remains at the 30 minute mark are a few sand grains and a cloud of clay .
the video shows an aggregate of soil resisting slaking (although there is some release of air bubbles) and undergoing visual clay dispersion within 30 seconds of immersion .
dispersive clays are relatively mobile within a soil. as they move they tend to clog soil pores and form layers of low permeability. surface sealing, restricted water transport and drainage, reduced macro - porosity, increased swelling, and increased soil erosion are likely outcomes .
flocculated clays tend to be stable and hence result in a relatively resilient soil structure. floccualated clays encourage soils to aggregate, and soils with stable aggregates allow water infiltration and drainage, provide pore spaces for air and water storage, provide housing for soil biology, and are more resistant to erosion .
. if your soil is sodic, soil testing to find out the concentration of exchangeable and soluble salts in your soil is needed. these numbers will provide you with the information to calculate whether treating the soil with gypsum is practical and cost effective for you .
content of your soils will also significantly improve the stability of your soil and its ability to resist dispersion when the soil is moist .
lastly, protecting the surface of your soil by maintaining ground cover will decrease the impact of raindrops and other mechanical disturbances on your soil that breakdown the soil and cause dispersion .
to assess your soil to see if it will disperse, there is a relatively quick and simply test that you can do yourself at home .
practical note: aggregate stability well aggregated soil is important. it has pores between aggregates and within the aggregate. large pores allow for the exchange of oxygen and other gases with the atmosphere, while small pores hold plant available water and dissolved nutrients .
. if your soil is sodic, soil testing to find out the concentration of exchangeable and soluble salts in your soil is needed. these numbers will provide you with the information to calculate whether treating the soil with gypsum is practicable and cost effective for you .
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mie theory requires knowledge of the optical properties (refractive index and imaginary component) of both the sample being measured, along with the refractive index of the dispersant. usually the optical properties of the dispersant are relatively easy to find from published data, and many modern instruments will have in - built databases that include common dispersants. for samples where the optical properties are not known, the user can either measure them or estimate them using an iterative approach based upon the goodness of fit between the modeled data and the actual data collected for the sample .
a simplified approach is to use the fraunhofer approximation, which does not require knowledge of the optical properties of the sample. this can provide accurate results for large particles. however it should be used with caution whenever working with samples which might have particles below 50µm or where the particles are relatively transparent .
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one of the excited levels of helium at 20. 61 ev is very close to a level in neon at 20. 66 ev, so close in fact that upon collision of a helium and a neon atom, the energy can be transferred from the helium to the neon atom .
this shows the beams from two helium - neon lasers passing through two lenses arranged in the galilean telescope geometry. the beams were made visible with a spray can of artificial smoke .
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these core principles explain much of the relationship between particle size and the angle and intensity of scattered light .
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the author examines the process of method development, with reference to iso 13320: 2009 and relevant monographs from the united states and european pharmacopoeias .
the company expanded its extended workbench laboratory services program to support the ongoing manufacturing and development of flexion therapeutics’s zilretta (triamcinolone acetonide extended - release injectable suspension) .
minakem’s facility in belgium enhances capacity to scale production of highly potent ingredients for small to full gmp batches .
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lactose is a white, crystalline slightly sweet tasting powder. it is a disaccharide consisting of glucose and galactose and is widely used as an excipient in the pharmaceutical industry. lactose powders are manufactured by selectively modifying the particle size, particle shape and particle size distribution of particles and they have special characteristics in terms of compactability, flow behaviour and granulability .
inspired by capsule technology, the coffee industry is constantly bringing new types of coffee onto the market that continue to stimulate consumption. this increases the requirements for quality control, particularly with respect to the particle size distribution of coffee powder. another challenge is the strong internationalisation of coffee producers, which makes comparability of analyses at different locations necessary. industrial grinding of coffee and frequent changes in variety require a consistent, partially automated control of the particle size distribution to ensure consistent product quality .
in a picturesque environment, edged by ponds of the harz mountains, the headquarter of sympatec gmbh
pulverhaus
is located on a plot of land, which has been moulded by the mining industry for centuries. its purpose is no longer the storage for explosive. it is home to design, manufacture and development of innovative particle sizing technologies .
optical setup | iso 13320, § 5, fig. 2 for particle size from 0. 1 µm to approx. 3. 0 mm
the process begins with a light source that generates a monochromatic beam. after passing through several optical components, the raw beam creates an expanded, collimated beam that illuminates particles in the scattering volume. the particles scatter light, generating unique angular scattering patterns .
these scattering patterns are transformed into a spatial intensity pattern that is detected by a multi - element photo - detector array. a photocurrent is subsequently processed and digitized, creating an intensity flux pattern that is converted into a particle size distribution .
not all products are available in all countries. product availability and regulatory status depends on country registration per applicable regulations the listed regulatory status for products correspond to one of the below: ivd: in vitro diagnostic products. these products are labeled
for in vitro diagnostic use .
asr: analyte specific reagents. these reagents are labeled
analyte specific reagents. analytical and performance characteristics are not established .
ce: products intended for in vitro diagnostic use and conforming to european directive (98 / 79 / ec). (note: devices may be ce marked to other directives than (98 / 79 / ec) ruo: research use only. these products are labeled
for research use only. not for use in diagnostic procedures .
luo: laboratory use only. these products are labeled
for laboratory use only .
no regulatory status: non - medical device or non - regulated articles. not for use in diagnostic or therapeutic procedures .
we can obtain information about the size of a particle using the angle and intensity of scattered light. diffracted and refracted light is useful for this purpose; absorbed and reflected light works against this purpose and must be taken into account during measurement and size calculation .
acquiring the best possible scattered light data is the basis of any reliable size measurement. the
raw
scattered light data is then passed to the calculation algorithm where it will be transformed into a particle size distribution .
considered a standard method in many industries because of its ability to characterise particles and for reasons of quality control .
huge advances have been made in instrumentation over at least the last two decades .
an absolute method grounded in fundamental scientific principles – in this method it is not necessary for an instrument to be calibrated against a standard. however, validation of equipment is possible to prove that it is performing to a standard that can be traced .
wide and dynamic range – in measuring particle size, good equipment will allow the user to measure particles sized between approximately 0. 1 and 2000 microns .
liquid suspensions and emulsions – it is possible to use a recirculating cell to measure liquid suspensions and emulsions. this technique promotes a high level of reproducibility and facilitates the use of dispersing agents and surfactants to determine the primary particle size. if it is possible to do so, it is preferable to take measurements in a liquid suspension .
rapid – this technique is so rapid that results can be derived in one minute or less. feedback can therefore quickly be provided to plants and repeat analyses can also be made quickly .
repeatable – this technique is highly repeatable and knowing that the results can be relied upon provides peace of mind .
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want an integrated method to measure particle morphology? check out this presentation to learn more about our visual validation solution, the partan si .
join us as we discuss dynamic light scattering technology and the on - line capabilities we offer. special guest, brian freeland from [ read more ]
weatherford laboratories offers a full range of special core analyses to address critical issues in your reservoir—from capillary pressure and fluid flow properties to petrophysics and rock mechanics .
geochemical analyses can help you assess gas quality, correlate oils to their source rocks, evaluate reservoir compartmentalization and allocate production. our geochemical laboratories provide a full range of analytical services .
weatherford laboratories provides comprehensive interpretive and analytic geologic services—ranging from petrographic analyses and fracture analyses, to sedimentologic and biostratigraphic studies—to support your exploration and production projects .
reservoir fluids change over the productive life of a field. weatherford laboratories collect and analyze fluids over time to help guide decisions that optimize production and development planning .
our houston - based laboratory services help to resolve oilfield issues related to water sourcing, flow assurance, corrosion mitigation, water injection, and treatment efficiency. after taking measures for appropriate water sampling and preservation, we execute projects involving fresh, formation, produced, injection, and disposal waters .
depending on the results, we can perform subsequent laboratory tests on scaling and water treatment processes. we also offer consulting services for scale, corrosion, water - production allocation, and more .
we provide a full spectrum of services—from wellsite retrieval to core storage. our project managers are your direct connection to the lab, helping you get the answers you need. we provide management services for the full life cycle of your cores. from wellsite sample retrieval and real - time, online laboratory test results, to long - term, bar - coded sample preservation and storage, you can gain access to the status of your samples and data anytime and from anywhere .
weatherford laboratories has the equipment, experience, and expertise to analyze any type of sample you collect, from outcrop samples to cuttings, cores, oils, gases, and waters .
privacy of your data is important to weatherford. we do not sell or rent your information to telemarketers. to find out more, please read our privacy policy .
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data availability: all relevant data are within the paper and its supporting information files .
soil psd is frequently assumed to follow a lognormal distribution [ 5, 6 ], although some soils do have a bimodal psd [ 7 ]. buchan and hwang compared five lognormal models and certain other types of models in terms of their fit to experimental psd data [ 8, 9 ]. their results showed that the bimodal model gave a marginally better fit, but incorporates a sub - clay mode, and the jaky model gave a good fit to data for many soils, better than the standard lognormal model for 23 soils. the latter included models based on water - retention curves [ 10 – 12 ], the fragmentation model [ 13 ], power - law functions based on fractal geometry [ 13, 14 ], exponential functions [ 15 ], gompertz equations [ 16 ], and a model estimating psd from limited soil texture data [ 17 ].
laser diffraction analysis , also known as laser diffraction spectroscopy , is a technology that utilizes diffraction patterns of a laser beam passed through any object ranging from nanometers to millimeters in size to quickly measure geometrical dimensions of a particle . this process does not depend on volumetric flow rate , the amount of particles that passes through a surface over time . 
laser diffraction analysis, also known as laser diffraction spectroscopy, is a technology that utilizes diffraction patterns of a laser beam passed through any object ranging from nanometers to millimeters in size to quickly measure geometrical dimensions of a particle. this process does not depend on volumetric flow rate, the amount of particles that passes through a surface over time.
laser diffraction analysis, also known as laser diffraction spectroscopy, is a technology that utilizes diffraction patterns of a laser beam passed through any object ranging from nanometers to millimeters in size to quickly measure geometrical dimensions of a particle. this process does not depend on volumetric flow rate, the amount of particles that passes through a surface over time.