Coarse Samples Research Articles

Differential effects of particulate matter upwind and downwind of an urban freeway in an allergic mouse model.

Near-road exposure to air pollutants has been associated with decreased lung function and other adverse health effects in susceptible populations. This study was designed to investigate whether different types of near-road particulate matter (PM) contribute to exacerbation of allergic asthma. Samples of upwind and downwind coarse, fine, and ultrafine PM were collected using a wind direction-actuated ChemVol sampler at a single site 100 m from Interstate-96 in Detroit, MI during winter 2010/2011. Upwind PM was enriched in crustal and wood combustion sources while downwind PM was dominated by traffic sources. Control and ovalbumin (OVA)-sensitized BALB/cJ mice were exposed via oropharyngeal (OP) aspiration to 20 or 100 μg of each PM sample 2 h prior to OP challenge with OVA. In OVA-allergic mice, 100 μg of downwind coarse PM caused greater increases than downwind fine/ultrafine PM in bronchoalveolar lavage neutrophils, eosinophils, and lactate dehydrogenase. Upwind fine PM (100 μg) produced greater increases in neutrophils and eosinophils compared to other upwind size fractions. Cytokine (IL-5) levels in BAL fluid also increased markedly following 100 μg downwind coarse and downwind ultrafine PM exposures. These findings indicate coarse PM downwind and fine PM upwind of an interstate highway promote inflammation in allergic mice.

Hydraulic Characteristics of Alluvial Gravels for Different Particle Sizes and Pressure Heads

The objective of this study was to characterize a very coarse alluvial vadose zone of the Ljubljana basin (Slovenia), with a gravel content >75%. A combination of the simplified evaporation experiment (HYPROP) and the dew point method (WP4 PotentiaMeter) was used to obtain the information across a wide moisture range. We obtained water retention data on fine (diameter <2 mm) and coarse samples (diameter <8 mm) and compared them with the mass‐based gravel correction. Measurements on coarse samples enabled us to determine (i) the influence of coarser particles on the shape of the water retention curve (WRC), (ii) if the retention curves are consistent with the decrease in the water content from fine to coarse to bulk samples, (iii) what known parametric models would be most suitable in representing hydraulic properties of coarse material, and (iv) if the mass‐based gravel correction is performing well for a coarse set of samples. The results of the study revealed that the vadose zone is represented by four major sedimentary textures, with the most dominant being well graded gravel followed by poorly graded gravel. The parameterization of the obtained data showed that both fine and coarse sets of data were best described with the bimodal van Genuchten model of Durner with the constrained conductivity model of Peters and Durner (VGbi‐PDI) and the bimodal van Genuchten model of Durner with the unconstrained conductivity model of Peters and Durner (VGbi‐PDII) across the whole moisture range. The measurements on the coarse set of samples led us to the conclusion that the mass‐based gravel corrections do not adequately describe the WRC of samples containing large amounts of gravel.

Exact Reconstruction of Signals in Evolutionary Systems Via Spatiotemporal Trade-off

We consider the problem of spatiotemporal sampling in which an initial state $f$ of an evolution process $f_t=A_tf$ is to be recovered from a combined set of coarse samples from varying time levels $\{t_1,\dots,t_N\}$. This new way of sampling, which we call dynamical sampling, differs from standard sampling since at any fixed time $t_i$ there are not enough samples to recover the function $f$ or the state $f_{t_i}$. Although dynamical sampling is an inverse problem, it differs from the typical inverse problems in which $f$ is to be recovered from $A_Tf$ for a single time $T$. In this paper, we consider signals that are modeled by $\ell^2(\mathbb Z)$ or a shift invariant space $V\subset L^2(\mathbb R)$.

Evaluation of different extraction methods on antimicrobial potency of Adenium obesum stem against food borne pathogenic bacterial strains in Oman

ObjectiveTo determine and compare the effect on antimicrobial potency of crude stems extract of Adenium obesum (A. obesum) by Soxhlet and maceration extraction methods. MethodsThe crude extracts were prepared from the coarse samples of stems with methanol by using Soxhlet and maceration extraction methods. Both the crude extracts from two extraction methods were dissolved in water and successively extracted by different polarities solvents with increasing polarities. In vitro antimicrobial potency of different polarities crude extracts obtained from Soxhlet and maceration methods was determined by agar gel diffusion method against different food borne pathogenic bacterial strains. ResultsThe results for antimicrobial potency of different crude extracts were almost similar by Soxhlet and maceration and methods. The average range of inhibition potency of different polarities crude extracts was 0%-17% by Soxhlet method and inhibition potency 0%-24% by maceration method. ConclusionsThese results obtained from in vitro approach give promising basic information about this plant as well as some potential crude extracts can be used for the treatment of infectious diseases.

Numerical study of particle segregation in a coal beneficiation fluidized bed by a TFM–DEM hybrid model: Influence of coal particle size and density

Abstract Particle segregation behavior in a coal beneficiation fluidized bed (CBFB) is numerically studied using a TFM–DEM hybrid model, in which the gas and the dense solid phases are modeled using a Eulerian–Eulerian or two fluid model (TFM), while the beneficiated coal particles are modeled as a dilute phase by the discrete element method (DEM). For validation purpose, the numerical model was setup using geometric and operating conditions similar to a laboratory experimental model with the bed thickness set to one particle diameter to save computational cost. For a fixed gas injection velocity, the influence of particle size and density of the beneficiated samples was studied. It was found that the particles would segregate along the bed height due to the density differences with the degree of segregation being strongly influenced by particle size. Obvious segregation occurs for the coarse samples (6.7 mm and 4.3 mm) and little segregation occurs for the particles smaller than 3 mm. The flow patterns and segregation kinetics were qualitatively comparable with those observed in physical experiments conducted under similar conditions. On this basis, the underlying mechanisms governing particle segregation have been explained in terms of the hydrodynamic forces acting on individual particles. It was demonstrated that the segregation of coarse particles was mainly controlled by the balance between gravity and the local pressure force, while fine particles were more strongly affected by the direct drag forces from the gas phase and the continuum solid phase, thus making them difficult to separate.

Diagenetic compaction experiments on simulated anhydrite fault gouge under static conditions

AbstractFaults that crosscut subsurface CO2 storage systems offer potential leakage pathways, especially if fault reactivation and dilation occur. After reactivation, however, newly formed fault gouge is expected to gradually compact and seal as a function of time. To estimate the time scale on which this occurs, the processes that control compaction must be understood. We performed uniaxial compaction experiments on simulated anhydrite fault gouge to investigate the deformation mechanisms that operate under postslip conditions in faulted anhydrite caprocks. This involved constant stress (5–12 MPa) and stress stepping experiments (5/7.5/10 MPa) performed at 80°C, under dry and wet conditions, on fault gouge samples prepared from crushed natural anhydrite sieved into different grain size fractions in the range 20–500 µm. Dry samples showed little to no compaction creep, whereas wet samples (i.e., flooded with presaturated CaSO4 solution) showed rapid compaction. Our mechanical data and microstructural observations on wet samples suggest that for fine grain sizes (<50 µm) and low stresses, gouge compaction is controlled by diffusion‐controlled pressure solution. With increasing grain size and stress, fluid‐assisted subcritical microcracking becomes dominant. Pressurizing solution‐flooded samples with CO2 (15 MPa) led to no significant effect on compaction rates in fine‐grained material, but it decreased compaction rates in coarse samples. Since fine grain sizes are expected in reactivated faults, we infer that pressure solution will dominate in anhydrite (cap)rocks, with extrapolation of our lab data to reservoir conditions suggesting sealing time scales of a few decades.

Determination of Phosphine in Plant Materials: Method Optimization and Validation in Interlaboratory Comparison Tests

The optimization and validation of a method for the determination of phosphine in plant materials are described. The method is based on headspace sampling over the sample heated in 5% sulfuric acid. Critical factors such as sample amount, equilibration conditions, method of quantitation, and matrix effects are discussed, and validation data are presented. Grinding of coarse samples does not lead to lower results and is a prerequisite for standard addition experiments, which present the most reliable approach for quantitation because of notable matrix effects. Two interlaboratory comparisons showed that results varied considerably and that an uncertainty of measurement of about 50% has to be assessed. Flame photometric and mass spectrometric detection gave similar results. The proposed method is well reproducible within one laboratory, and results from the authors' laboratories using different injection and detection techniques are very close to each other. The considerable variation in the interlaboratory comparison shows that this analysis is still challenging in practice and further proficiency testing is needed.

THE ROLE OF ORE PROPERTIES IN THICKENING PROCESS

The role of ore properties (density, particle size, and mineralogy) in thickening process was studied in this research. The shaking table was used to prepare the sample for the tests. The tailings were continuously fed on the table by gravity to separate the tailings in three products as slime, middling and coarse particles. The solid density and particle size of the samples were different. To study the effect of mineralogical properties, the sedimentation behavior of the feed and middling samples were tested. The results showed that the free settling velocity of the feed (2-6 mm/s) was less than that of the middling sample (18-23 mm/s), and the compressibility of middling (density: 0.63-0.86 Mg/m 3 ) was more than that of feed (density: 0.33-0.47 Mg/m 3 ). This was due to the amount of clay reduction in the middling sample. The sedimentation behavior of the slime and the coarse samples were also compared in order to study the effect of particle size and density. The settling velocity of the slime and the coarse particles was obtained as 0.1-0.4 and 26 mm/s, respectively, and the maximum underflow density were obtained as 0.35 and 1.57 Mg/m 3 , respectively. Therefore, the particle size and density reduction reduced the thickener performance. In order to study the effect of particle size, the sedimentation behavior of the slime and coarse samples were compared, and it was obtained that the settling velocity and underflow density increased with the increasing in the particle size.

The Technical Analysis on Upgrade and Coupling of Low-Quality Coal

Experimental study was conducted with regard to upgrading low-quality coal by low temperature pyrolysis technology and fluidization classification technology, which laid the theoretical foundation for research and development of low-quality coal upgrading process. Firstly, a pyrolysis pilot experiment of long-flame coal was performed and the optimum pyrolysis conditions were found. When the final pyrolysis temperature was 450?C and the residence time was 10 minutes, the content of semicoke volatile dry ash-free was about 22.89% and the content of semicoke ash was about 16.1%. More than 5% of the ash needs to be removed before entering the pyrolysis fluidized bed. Thus, classification tests were carried out to pick out the coal particles with the target size of 500 μm, using a gas-solid fluidized bed coal picker. It was found that the separating effect of coal particles was the most satisfactory when the inlet velocity at the bottom was 3.27 m/s. The percentage of particles with diameters less than 500 μm was as low as 28.7% in the coarse samples. Based on the test results, a novel process of low-quality coal upgrade and coupling was proposed, which realized the sorting, grading, drying and pyrolysis of low-quality coal through the multi-stage fluidized bed integrated process.

Acoustic Chemometric At-Line Characterization for Monitoring Particle Size Fractions in Pneumatically Conveyed Biomass

Reliable on-line/at-line prediction of particle size fractions of biomass material is a process monitoring concern owing to inherent variation in particle size and difficulty in sampling of pneumatically ducted biomass material. A feasibility study on application of acoustic chemometrics for at-line prediction of size fractions of biomass material has been performed, with all models subjected to independent test set validation. This study serves as a platform for at-line characterization of biomass samples from a sampling device extracting biomass samples from pneumatic conveying systems (based on theory of sampling). A prestudy using complex biomass/plastic pellets mixtures was used to test reliability and robustness of the experimental setup. Promising prediction results were achieved (slope, relative root mean square error of prediction (RMSEPrel), and correlation coefficient (r2) were 1.08, 24.94%, and 0.90, respectively). The same experimental setup was adapted for quantitative prediction of coarse versus fine biomass mixtures (the main objective) with satisfactory results; slope = 0.96, r2 = 0.97, RMSEP(rel) = 11%. A case study was also performed showing the adverse effect of using nonrepresentative coarse versus fine biomass samples for calibration. It is concluded that acoustic chemometrics is a viable technique for at-line prediction of size fractions of representative biomass materials.

The effect of processing parameters on the physicochemical properties of oil from roselle seed

PurposeThe study aimed to focus on the effect of the processing parameters on the physicochemical properties of oil from roselle seed.Design/methodology/approachFine and coarse samples of the ground roselle seeds were conditioned to the moisture contents of 4.4‐10.4 per cent and 5.14‐11.14 per cent. Oil was expressed at applied pressures of 15‐37.5 MPa with 7.5 MPa interval using hydraulic oil extractor for between 10‐40 min. at increment of 10 min. and at the heating temperatures of 80, 90, 100 and 110°C over a period of 15‐30 min. at an increment of 5 min. All the physicochemical properties were determined using AOAC and AOCS methods [AOAC, 1984; AOCS, 1994].FindingsThe free fatty acid, peroxide values and the colour intensity of the oil were affected by the processing parameters; while saponification value, viscosity, specific gravity, refractive index and the iodine value of the oil were not affected by the expression parameters.Originality/valueProcessing parameters were found to affect the quality attributes of free fatty acid, peroxide values and the colour intensity of the oil.

The effect of liming on antibacterial and hormone levels in wastewater biosolids

This study analyzes the effect of liming on levels of triclocarban (TCC), triclosan (TCS), estrone (E1), and progesterone (P), two antimicrobial agents and two natural hormones, respectively. Factors studied include lime particle size, mixing time, and overall lime contact time. The study results suggest that coarse lime may be more active than fine lime due to less interaction with surrounding air. Both TCS and TCC concentrations were lower in coarse limed samples versus unlimed samples and the decrease was a function of time. A similar, but statistically insignificant trend in TCC and TCS levels was observed in fine lime samples with respect to unlimed samples. Liming was also found to decrease apparent E1 levels, with more notable decreases in samples amended with coarse lime. P-levels significantly increased after 1-day of contact time, stabilizing over the next 14 days of the study period. This increase and stabilization of P-levels was attributed to the pH and moisture-driven conversion of more chemically complex steroids into P.

INFLUENCE OF OPHIOLITIC ROCKS ON THE SPATIAL DISTRIBUTION OF CHROMIUM AND NICKEL IN STREAM SEDIMENTS OF THE CECINA RIVER BASIN (TUSCANY, ITALY)

The concentrations of Cr and Ni and other heavy metals (Cd, Cu, Pb, Zn) have been determined in stream sediments collected into the Cecina River basin (Tuscany, Italy) in order to evaluate Cr and Ni levels and their spatial distribution and origin. An aqua regia digestion coupled to ICP-MS analysis has been performed on the samples. The distribution of Cr and Ni concentration as a function of grain size was also investigated, comparing finer samples (< 63 µm) and coarse samples (< 2000 µm). In Possera Creek samples, a left tributary of the Cecina River, another sieve fraction (< 125 µm) was sampled. The high lev- els of Cr and Ni in the stream sediments often exceed the thresholds of the Italian law currently in force (Legislative Decree No. 152/2006). Multivariate data analysis techniques (Hierarchical Clustering Analysis, HCA) were used to obtain information about the potential sources of heavy metals. The results indicate an Cr and Ni enrichment in stream sediments due to the presence of some extensive outcrops of serpentinized ultramafic rocks (ophiolites). The enrichment is major in the < 2000 µm fraction compared to the < 63 µm fraction.

Polycyclic aromatic hydrocarbons (PAHs) in fine and coarse particles

&lt;p&gt;About 140 samplings of fine and coarse particles were gathered during the year 2006 in Kozani that represent an urban area surrounded by opencast coal mining. A low volume dichotomus sampler has been used to trap suspended particles. The filters used were teflon, which are ideal for analysis in the determination of PAHs. The determination of Polycyclic Aromatic Hydrocarbons (PAHs) has been carried out by the use of the analytic technique of large volume injection and gas chromatography – mass spectrometry (LVI - GC/MS). The extraction of substances has been made in a two stage procedure, firstly with agitation in a magnetic shaker and secondly by the use of ultrasonic bath. This technique has given high recoveries of PAHs, in short time intervals. The mean daily concentrations of fine particles varied from 4 to 48 μg m-3 and annual mean was 16 μg m-3. The mean daily concentrations of coarse particles respectively varied from 2 to 67 μg m-3 with 23 μg m-3 annual mean concentration. The ΣPAH concentrations for fine samples were 4.80 ± 7.06 ng m-3 and for coarse samples were 1.36 ± 1.59 ng m-3. The mean B[a]Py concentration for fine particles was 0.38 ng m-3. Finally, diagnostic ratios were used to characterize and identify PAHs emission source in this study.&lt;/p&gt;

Instrumental neutron activation analysis for the study of size-fractionated airborne particulate matter samples

Abstract In order to devise methodology to study various environmental matrices 28 pairs of coarse and fine air particulate samples were collected in the vicinity of an automotive workshop located at Tasmasipabad on Chaklala Road, Rawalpindi. The samples were collected using a Gent sampler and polycarbonate filters during the period 7 to 27 April 2009. These samples were analyzed using instrumental neutron activation analysis (INAA) using the low power Pakistan Atomic Research Reactor-2 (PARR-2). Reference materials (RMs) IAEA-SL1 and IAEA-S7 were used for calibration and quality assurance (QA) purpose. The gravimetric data for these samples were found to exceed the PM2.5 and PM10 national limits. Up to 34 elements were measured using the INAA optimized procedure.

Stereological and Statistical Evaluation of Grain Size in Experimental Ni-Based and Conventional Supercoarse Sintered Carbides

Chemical composition and technology of experimental Ni based binder-tungsten carbide particles composite have been worked out to increase corrosion resistance of conventional supercoarse WC-Co type sintered carbides. All the sintered WC cermets, both with Co and Ni-based binding phase have been manufactured using identical supercoarse WC powder. Grain size evaluation was performed using light microscope images and grain chord length measurements, samples of commercial WC-Co coarse and supercoarse grades being included into analysis for comparison purposes. The obtained statistical and geometrical distributions of the chord length revealed certain differences. The performed statistical analysis allowed to state that the investigated experimental grades of Ni-based sintered WC carbides are materials of microstructure significantly more coarse than the reference coarse commercial grade (i.e. they can be classified into supercoarse group of sintered carbides).

Effects of Particle Size, Applied Pressure and Pressing Time on the Yield of Oil Expressed from Almond Seed

An investigation of the effects of particle size, applied pressure and pressing time on the yield of oil expressed from almond seeds was undertaken. The oil was expressed mechanically using a mini laboratory oil press. The fixed processing parameters were: moisture content of 17% wet basis, heating temperature of 65 – 70°C and heating time of 15 min. The pressing pressures used were 60.6 kPa, 101.3 kPa and 116.6 kPa. Pressing times used were 2, 4, 8 and 12 min, and particle size of Φ < 0.5 mm (fine sample) and Φ > 0.5 mm (coarse sample) were used. The result shows that oil yield increased with increase in applied pressure and pressing time, however result obtained from fine and coarse sample sizes are similar. Pressing time and applied pressure had significant (p < 0.05) difference on oil yield; particle size had no significant (p > 0.05) difference on oil yield. Regression and correlation analysis gave a reasonable experimental prediction between oil yield and applied pressure with correlation coefficient r = 0.952 and also with pressing time with r = 0.7342. Higher oil yields were obtained from samples with fine particles size (Φ < 0.5 mm) and coarse particles size (Φ > 0.5 mm) samples pressed at 116.6 kPa pressure for 12 min. Maximum oil yields of 48.44% and 48.40% were obtained from coarse and fine samples respectively. The results obtained can be used in the design of a suitable process and machine for the expression of oil from almond seed.

Diatom assemblages in surface sediments from the South China Sea as environmental indicators

We studied diatom distribution from 62 samples from the uppermost 1 cm of sediment in the South China Sea (SCS), using grabs or box corers in three cruises between 2001–2007. Fifty six genera, 256 species and their varieties were identified. Dominating species included Coscinodiscus africanus, Coscinodiscus nodulifer, Cyclotella stylorum, Hemidiscus cuneiformis, Melosira sulcata, Nitzschia marina, Roperia tesselata, Thalassionema nitzschioides, Thalassiosira excentrica, and Thalassiothrix longissima. Most surface sediments in the SCS were rich in diatoms, except for a few coarse samples. Average diatom abundance in the study area was 104 607 valve/g. In terms of the abundance, ecology, and spatial distribution, seven diatom zones (Zones 1–7) were recognized. Zone 1 (northern continental shelf) is affected by warm currents, SCS northern branch of the Kuroshio, and northern coastal currents; Zone 2 (northwestern continental shelf) is affected by intense coastal currents; Zone 3 (Xisha Islands sea area) is a bathyal environment with transitional water masses; Zone 4 (sea basin) is a bathyal-to-deep sea with stable and uniform central water masses in a semi-enclosed marginal sea; Zone 5 (Nansha Islands marine area) is a pelagic environment with relatively high surface temperature; Zone 6 (northern Sunda Shelf) is a tropical shelf environment; and Zone 7 (northern Kalimantan Island shelf area) is affected by warm waters from the Indian Ocean and coastal waters. The data indicate that these diatom zones are closely related to topography, hydrodynamics, temperature, nutrients and especially the salinity. Better understanding of the relationship between diatom distribution and the oceanographic factors would help in the reconstruction of the SCS in the past.

Influence of angularity of coarse fraction grains on internal erosion process

This paper deals with suffusion process also named internal instability, which takes place inside the soil skeleton. In this process, finer particles of a soil migrate within its own pore spaces. These fine particles can be cohesionless particles or clay particles. With the objective to study the effect of angularity of coarse fraction grains on suffusion a series of tests was performed on different clayey sand. Three coarse fraction type samples were tested which are different by the grain size distribution and also by the angularity of grains. A specific triaxial device was used in order to force fluid through the samples in downward direction under constant hydraulic gradients.It is shown that the angularity of coarse fraction grains may contribute to increase the erosion resistance of the tested soils by a factor of 5. Moreover for the tested soils, the grain shape has an effect on hydraulic conductivity decrease. The angularity of coarse fraction grains may intensify the geometric blocking of detached clay particles.Finally a study is conducted to compare the different ways to characterize the angularity of grains: by an analysis of grain pictures, by using an angulometer or by measuring the internal friction angle.

Bacterial and Archaeal Diversity in Sediments of West Lake Bonney, McMurdo Dry Valleys, Antarctica

Bacterial and archaeal diversity was examined in a sediment core from Lake Bonney, Antarctica. Members of the Archaea showed both low abundance and diversity, whereas bacterial diversity was moderately high and some phyla were fairly abundant, even in geologically old samples. Microbial diversity correlated with sample texture and differed in silty and coarse samples.