We present new observational data on small‐angle light scattering properties of natural, random shaped particles, as contrasted with spherical particles. The interest in this “shape effect” on ...scattering arises from the need for a suitable kernel matrix for use in the laser diffraction method (LD) of particle sizing. LD is now used broadly for measuring size distribution of suspended marine particles. LD involves the measurement of small‐angle forward scattering at multiple angles. This data is inverted using the kernel matrix to produce size distribution. In the absence of a suitable matrix for random shaped particles, past practice has been to use a model based on Mie theory, applicable strictly only to homogeneous spheres. The present work replaces Mie theory with empirical data. The work was motivated in part by anomalous field observations of size distribution and settling velocity distributions reported in literature. We show that a kernel matrix for random shaped particles results in improved interpretation of field multiangle scattering observations. In particular, a rising edge at the fine particle end of the size spectrum is shown to be associated with shape effects.
In this paper we describe two sensors for measurement of particle size-distribution and settling-velocity distribution. These measurements are critical to the correct estimation of the true sediment ...concentration in the field, as well as to evaluating models for transport rates of sediments. A multi-angle measurement of laser scattering is made and inverted to obtain the particle size distribution. Since small-angle scattering is relatively insensitive to particle composition, the size distribution measurements are robust, and do not require particle refractive index. It is shown that with a knowledge of the size distribution, true particulate volume concentration can be obtained, unaffected in calibration by changes in particle size distribution. The data from bottom boundary layer experiments using the instrument show the presence of temporal variability in size distribution associated with the strength of forcing of the boundary layer. The importance of these observations lies in the implication that historical data acquired with single-parameter optical or other sensors needs to be revisited. In the second instrument, analyzing the observation of size distributions during settling in a settling column produces settling velocity estimates. In this case, the history of concentration of each size class is examined to determine the settling velocity, without invoking any assumptions of settling regime. Settling velocity data from a field experiment off the New Jersey coast fit the model:
w
f,n
=0.45×10
−3
a
n
1.2.
where
a
n
is radius in microns and settling velocity is in cm/s.
We construct vertical profiles of the acoustic attenuation and back‐scattering properties of a river column from measured particle concentration and size distribution profiles. The particle size and ...concentration data were collected in situ in the Cowlitz River in Washington, U.S., using a laser diffraction‐instrument LISST‐SL. The particle size distribution was bimodal, comprising a vertically well‐mixed washload, and a suspended load that was similar to Rouse profiles. We then explore how well the results of converting these synthetic profiles to recover an acoustic equivalent sediment concentration and acoustic equivalent size compare with laser data in this bimodal environment. The acoustic scattering and attenuation properties are computed for four distinct frequencies: 0.5, 1, 3, and 5 MHz. It is seen that at the lowest frequency, 500 KHz, the acoustic attenuation throughout the water column is nearly constant and determined primarily by particles of size smaller than ∼30 microns, i.e., the washload. At the next higher frequency, 1 MHz, the suspended load also contributed to attenuation, but even so, attenuation remained nearly constant over the vertical profile. Thus, at the two lower frequencies, attenuation was decoupled from scattering, making the inverse problem explicit for inversion. In contrast, at the two highest frequencies, scattering of sound by the suspended mode became the dominant contributor to attenuation, and attenuation varied by an order of magnitude over river depth. As for backscatter, the computed acoustic backscatter strength was determined by a combination of the washload and suspended sediment mode at all four frequencies. A fairly narrow monotonic relationship was found between total sediment concentration and locally computed backscatter, effectively providing a calibration between local backscatter signal strength and suspended sediment concentration. Such a relationship existed throughout the water column, for every frequency. The sediment concentration derived from backscatter at a pair of frequencies was within ∼50% of the value measured by laser diffraction; however, the acoustic equivalent diameter exceeded the laser volume mean diameter by up to an order of magnitude. The robustness of these results for application to other flow regimes or rivers remains to be investigated.
Key Points:
Fines dominate attenuation at low frequency
Single‐ frequency calibration possible
Two frequency systems recover mass but not size
We analysed the reproducibility of Ki67 labelling index (LI) between two scorers using the International Ki67 Working Group (IKWG) global methods on an Android application (APP), correlated the APP ...and eyeball estimate (EBE) with digital image analysis (DIA) scores and determined the prognostic significance of Ki67LI. Global weighted (GW) and global unweighted (GUW) Ki67 app scores of hormone receptor‐positive and HER2 (human epidermal growth factor receptor 2)‐negative breast cancer patients were obtained. Reproducibility of Ki67LI between 2 scorers and correlation of APP and EBE scores with DIA scores were performed. The prognostic significance of APP scores and its correlation with other clinico‐pathologic variables were evaluated. The intra‐class correlation coefficient (ICC) between 2 scorers showed excellent reliability with both GW and GUW methods. ICC between DIA and APP scores was significantly greater than DIA versus EBE. The three categories of APP scores based on median value and cut points of 10%, 18% and 38% were significantly associated with poor DFS. On multivariate analysis, significant association between Ki67LI, tumour size, nodal involvement and DFS was noted. Our study shows that the visual Ki67 scoring app is effective in bringing consistency to KI67LI and APP scores showed significant correlation with DFS.
To resolve the phylogeny of the autochthonous mitochondrial DNA (mtDNA) haplogroups of India and determine the relationship between the Indian and western Eurasian mtDNA pools more precisely, a ...diverse subset of 75 macrohaplogroup N lineages was chosen for complete sequencing from a collection of >800 control-region sequences sampled across India. We identified five new autochthonous haplogroups (R7, R8, R30, R31, and N5) and fully characterized the autochthonous haplogroups (R5, R6, N1d, U2a, U2b, and U2c) that were previously described only by first hypervariable segment (HVS-I) sequencing and coding-region restriction-fragment–length polymorphism analysis. Our findings demonstrate that the Indian mtDNA pool, even when restricted to macrohaplogroup N, harbors at least as many deepest-branching lineages as the western Eurasian mtDNA pool. Moreover, the distribution of the earliest branches within haplogroups M, N, and R across Eurasia and Oceania provides additional evidence for a three-founder-mtDNA scenario and a single migration route out of Africa.
Application of riverbed sand, a non-toxic substance for the removal of Cr(VI) for aqueous solutions has been investigated. Removal of Cr(VI) was dependent on initial concentration and removal ...increased from 43.2% to 74.3% by decreasing initial concentration from 7.5
×
10
−5
M to 1.0
×
10
−5
M at 25
°C, 1.0
×
10
−2
M NaClO
4 ionic strength and 100
rpm. Higher removal was obtained at particles of smaller sizes of the adsorbent. Removal decreased from 74.3% to 40.7% by increasing temperature from 25
°C to 35
°C exhibiting exothermic nature of the process of removal. Thermodynamic parameters, namely change in free energy (Δ
G°), enthalpy (Δ
H°) and entropy (Δ
S°), were calculated and were found to be −0.81
kcal
mol
−1, −17.21
kcal
mol
−1 and 56.94
cal
mol
−1, respectively at 25
°C. pH of the solution has pronounced effect on the removal and higher removal was obtained in acidic pH ranges, maximum (74.3%) being at 2.5 pH.
Flocculation has a great influence on the biogeochemical cycle by altering the particle size, density and settling velocity of suspended particulate matter (SPM) from coastal to shelf sea areas. ...However, the flocculation process in the shelf sea areas of China has not been systematically studied. In this study, the influencing mechanism of the North Yellow Sea cold water mass (NYSCWM) on the distribution and flocculation process of SPM is studied based on a comprehensive investigation during the summer of 2016. The results revealed that the mass concentration and turbidity of SPM showed a decreasing trend from coastal to offshore areas and an increasing trend from surface to near-benthic layers. Sediments from the Shandong subaqueous clinoform that were resuspended by the tidal mixing effect were the main source of inorganic SPM in the North Yellow Sea in summer. The existence of the bottom cold water mass enhanced the thermocline and pycnocline in the North Yellow Sea shelf area. The pycnocline obstructed the vertical diffusion of nutrients in the NYSCWM, resulting in a subsurface maximum chlorophyll a (chl a) layer, which further contributed to the maximum subsurface volume concentration of SPM. Flocculation was ubiquitous in the study area and was the main reason for the asynchronous variability in the mass concentration, turbidity and volume concentration of SPM. Three different kinds of flocculation mechanisms were identified, including the effects of biological activities in water masses above the NYSCWM, physicochemical effects in the near-benthic nepheloid layer within the NYSCWM, and their combined effects in shallow coastal areas. The flocculation of SPM enhanced the transport of particles from the surface to the bottom of the water column and made an important contribution to the formation of the North Yellow Sea mud deposit.
•The CWM changed the marine physical and biological environments, resulting in variations in SPM flocculation conditions.•Three flocculation mechanisms, dominated by biological activity, physicochemical effects and their coeffects are proposed.•The flocculation processes of SPM play important roles in the formation of mud deposits in the North Yellow Sea.
The Spherical Neutron Polarimetry (SNP) Technique probes complex magnetic structures which are inaccessible by other methods. This technique is achieved by combining a zero-field sample chamber with ...full control of incoming and outgoing neutron polarization. While wide-angle SNP capability has been fully implemented in Europe, it is still in development in the US. At Oak Ridge National Laboratory, we are developing a wide-angle SNP capability suited for multiple neutron beamlines. The design is based on the basic concept of SNP while utilizing high-Tc superconducting films and Mu-metal. In this article we report our recent development of the SNP capability and its future applications.
Soyflakes and soybrokens were enzymatically hydrolyzed using a mixed-activity crude enzyme prior to extraction of oil using hexane. To enhance oil availability and extractability, a second order ...response surface methodology was used to obtain optimal process conditions for soyflakes and soybrokens of 24.6% and 24.7% wet mass basis (wb) moisture during hydrolysis, 14.2% and 7.1% volume per weight of the sample (v/w) enzyme concentration, and 13.3 and 13.9
h hydrolysis time, respectively. Enzymatic hydrolysis significantly increased the extraction rates. The enzymatic hydrolysis reduced the extraction time for over 99% extraction from 28
h to 14
h in soyflakes and from 32
h to 21
h in soybrokens under the optimum process conditions. Mathematical models were developed to describe the extraction kinetics of both enzymatically hydrolyzed and unhydrolyzed soyflakes and soybrokens. Observed experimental oil extraction data fitted well with the developed mathematical models.
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