Median Particle Size Research Articles

Production of recycled paper using harmless municipal sludge as a new biomass filler

Abstract Due to a shortage of resources, exploring new biomass fillers has become critical for paper making. In this study, we reported an eco-friendly strategy for fabricating low-cost and efficient recycled paper with high mechanical properties using corrugated cardboard waste paper and harmless municipal sludge (HMS). First, the characteristics of HMS, including the particle size, pH, specific surface area, organic functional groups and organic component content, were analyzed. Then, the influence of the amount of HMS on the properties of the recycled paper was studied. Finally, the strengthening mechanism of biomass filling recycled paper was discussed. The results showed that HMS, a biomass filler for recycled paper preparation, exhibited excellent physical and chemical properties, with a median particle size of 6.395 μm, a surface area of 39.974 m2 g−1 and organic functional groups. The tensile index of the recycled paper with 30 % HMS was 13.10 Nm/g, which was 16.4 % greater than that of the unfilled paper and showed better thermal stability. This excellent performance could be attributed to the uniform distribution of HMS on the fiber surface, which improved the accessibility of hydrogen bond formation between fibers. Thus, this study proved that HMS was an excellent biomass filler for producing recycled paper.

Experimental Study on Tailings Deposition Distribution Pattern and Sedimentation Characteristics.

Tailings pond accidents frequently occur during an extended period, resulting in loss of life and property, wastage of resources, and environmental pollution. Relying on tailings pond engineering, this paper carried out sample particle fragmentation experiments and settling column experiments to explore the deposition distribution pattern of tailings in both horizontal and vertical directions as well as the impact of particle size distribution on the sedimentation stratification effect. The results show that the median particle size on the dry beach surface in the horizontal direction slowly decreased with the increase in the distance from the subdam. The particle size of tailings showed great fluctuations in the vertical direction, which gradually became finer with the increase in the depth overall. At the same time, saturated sedimentation experiments suggested the inconsistent variation rule with the field test, namely, coarse on the bottom and fine at the top, and the change in particle size greatly affected the tailing sedimentation stratification effect. With the increase in fine particle content in tailings, the appearance time of the water-sand interface was shortened to within 30 min, but the sedimentation and consolidation completion times were delayed to about 1400 min. The settling column results indicate that the increase in fine particle content gradually weakened the sedimentation stratification effect, and the sedimentation pattern transformed from independent sedimentation to floc-type average sedimentation, which led to the enhanced water-retaining property of the settled layer. This may lead to an increase in the saturation line and a decrease in the length of the dry beach, seriously affecting the safe operation of the tailings pond. The research results provide some theoretical guidance and basic data for analyzing the consolidation efficiency of tailings and the stability of the tailings pond.

Supplementary cementitious material based on calcined montmorillonite standards

The most effective approach to mitigating the environmental impact of cement production is through the utilisation of pozzolanic materials to prepare blended cement. Calcined kaolinitic clays are one of the most promising materials to be used as supplementary cementitious materials (SCM) due to their final performances. However, there are locations where kaolinitic rocks are not available. This work presents the study of two dioctahedral smectite standards from the Clay Minerals Society (CMS), SWy-3 and SAu-1, to be used as references. After thermal activation optimisation, their pozzolanic performances are compared with those of low-grade kaolinitic clay. On the one hand, raw SWy-3 has an amorphous content of ∼80 wt%, considered montmorillonite, with quartz and feldspars. The optimum calcination temperature was 800ºC, at which the smectite is fully dehydroxylated (as determined by thermal analysis) but not completely amorphized (as shown by powder diffraction). After calcination (800ºC), with a median particle size by volume (Dv,50) of ∼11 μm, ∼480 J/g were released at 7 days in the R3 test. On the other hand, SAu-1 has a higher amount of amorphous content, ∼96 wt%, which includes interstratified illite/smectite. The optimum calcination temperature was found to be 750ºC. This sample (Dv,50 ∼10 μm) gave 452 J/g at 7 days in the R3 test. The optimised active smectites gave a pozzolanic activity comparable to clay with 30–35 % kaolinite, as determined, for the first time, by the R3 test. This work has established descriptors for the activation of natural smectites/bentonites and reference values for the resulting smectite-based SCMs.

Effect of synergistic fermentation of Saccharomyces cerevisiae and Lactobacillus plantarum on thermal properties of hyaluronic acid-wheat starch system

Hyaluronic acid (HA), as a multifunctional hydrophilic polysaccharide, is potentially beneficial in improving the thermal stability of fermented modified starches, but relevant insights at the molecular level are lacking. The aim of this study was to investigate the effect of different levels (0 %, 3 %, 6 %, 9 %, 12 % and 15 %) of HA on the structural, thermal and pasting properties of wheat starch co-fermented with Saccharomyces cerevisiae and Lactobacillus plantarum. We found that the addition of HA increased the median particle size of fermented starch granules from 16.387 to 17.070 μm. Meanwhile, the crystallinity of fermented starch was negatively correlated with the HA content, decreasing from 14.70 % to 12.80 % (p < 0.05). Fourier transform infrared spectroscopy results confirmed that HA interacted with starch granules and water molecules mainly through hydrogen bonding. Thermal analyses showed that the thermal peak of the composite correlated with the HA concentration, reaching a maximum of 73.17 °C at 12 % HA. In addition, HA increases the pasting temperature, reduces the peak, breakdown and setback viscosities of starch. This study demonstrates the role of HA in improving the thermal stability of fermented starch, providing new insights for traditional fermented food research and the application of HA in food processing.

Characterization of stratospheric particle size distribution uncertainties using SAGE II and SAGE III/ISS extinction spectra

Abstract. A new algorithm was developed to infer particle size distribution parameters from the Stratospheric Aerosol and Gas Experiment II (SAGE II) and SAGE III on the International Space Station (SAGE III/ISS) extinction spectra using a lookup table (LUT) approach. Here, the SAGE-based extinction ratios were matched to LUT values, and, using these matches, weighted statistics were calculated to infer the median particle size distribution values and higher-moment parameters as well as quantify the uncertainty in these estimates. This was carried out by solving for both single-mode and bimodal lognormal distributions. The work presented herein falls under two general headings: (1) a theoretical study was carried out to determine the accuracy of this methodology, and (2) the solution algorithm was applied to the SAGE II and SAGE III/ISS records with a brief case study analysis of the 2022 Hunga Tonga eruption. This methodology was demonstrated to be ≈ 25 % accurate for mode radius and has a minor dependence on particle composition. While bimodal solutions were obtained from this algorithm, we provide a conclusive demonstration of how and why these estimates are inherently unstable using SAGE III/ISS extinction spectra alone. Finally, we demonstrated how the Hunga Tonga aerosol plume evolved in regard to both size and transport over 18 months after the 2022 Hunga Tonga eruption. The particle size distribution (PSD) estimates, higher-moment parameters, and uncertainties are new products within the SAGE III/ISS Level 2 (L2) products, are currently available for download, and will be merged into the main SAGE III/ISS release products in a subsequent L2 release.

Experimental Study on the Sedimentation Performance of an Arc-Plate Linear Sedimentation Tank

To examine the influence of plate shapes and quantities on the sedimentation performance of a linear sedimentation tank, experimental research was conducted using tanks featuring five distinct plate structures. The findings reveal that when subjected to an inflow rate ranging from 60 to 100 m3/h and with median particle sizes of 571.110 μm and 162.254 μm, for sediment particles in water containing sediment, the flow field distribution in the arc-plate sedimentation tank facilitates the effective settling of sediment particles. Comparative analyses indicate that incorporating eight arc plates in the sedimentation tank, as opposed to an equal number of inclined plates, results in a notable reduction in surface sediment concentration within the plate region, ranging from approximately 8 to 34%. Additionally, the mass percentage of sediment particles with sizes less than 0.05 mm at the tank bottom increases by about 5–7%. Moreover, in comparison to tanks lacking plates and those equipped with four arc plates, the surface sediment concentration experiences a significant decrease, ranging from approximately 33% to 60% and 18% to 44%, respectively. Concurrently, the mass percentage of sediment particles with sizes less than 0.05 mm shows an increase of about 25–32% and 10–20%. The arc-plate sedimentation tank exhibits superior sedimentation efficiency with an inflow rate of 60 m3/h and the installation of eight arc plates. Additionally, the study concludes that increasing the number of plates and reducing the inflow rate enhance sediment settling. The research findings offer valuable insights for the design and advancement of sedimentation tanks.

Visualization of phenanthrene effect on biochar colloids transport in porous media

Biochar colloids (BCs) can be used as adsorbent materials for remediation of phenanthrene due to their high specific surface area and other characteristics. Understanding the effects of phenanthrene on the transport of BCs contributes to facilitate the removal of phenanthrene in soil and water habitats. In this work, the influence of phenanthrene on the transport of BCs under different environmental factors (pH, ionic strength (IS), media size) in a one-dimensional sand column was firstly explored together with a real-time visualization system to explore the transport mechanism of BCs in two-dimensional sand tank. The results show that phenanthrene adsorbed on the surface of BCs, shielded its surface charge and reduced the mobility of BCs in porous media. Acidic conditions promoted the agglomeration of BCs and adsorption of phenanthrene, resulting in a 51.03 % decrease in the maximum breakthrough rate of BCs compared to alkaline conditions. The same was true for the high IS condition, where the maximum breakthrough rate of BCs was only 0.95 % at IS = 50. Additionally, there was a substantial and positive correlation between media particle size and BCs mobility. As the quartz sand particle size increased, the maximum breakthrough rates of BCs were 2.67 %, 33.28 %, and 52.27 % in the 1-D experiment, and 0, 13.88 %, and 13.10 % in the 2-D experiment, respectively. The contact area of BCs with the medium expands under the fine particle size condition, leading to a significant decrease in the mobility of BCs at low potentials influenced by phenanthrene. This finding is significant for biochar application in phenanthrene contaminated soil and groundwater remediation.

Effect of particles on foam drainage

Despite many applications, the three phase foam is so complicated and far from being fully understood. Drainage is critical to foam decay, so the effect of particles on foam drainage has been investigated in this research to better understand the complex three phase foam. The power law relationship, drainage regime, foam permeability and the residual solid particles were investigated with different particle concentration, particle hydrophobicity and particle size. It was found that the power law index increased with the increasing of particle concentration and particle hydrophobicity, which indicates the transition of drainage regime from node dominated to Plateau border dominated. It was also found that the medium size particles could increase the Plateau border viscous loss more obviously. Foam permeability with different particles was also discussed via fitting the viscous loss of both Plateau border and nodes. Finally, residual solid particle was used to study the particle behaviour during the free drainage after forced drainage. This research could help us better understand the drainage of three phase foam.

Study on the Preparation of Spherical Nanosilver Particles Using Ammonium Citrate and Polyvinyl Alcohol as Surfactants

Spherical nanosilver particles were synthesized using ammonium citrate (AC) and polyvinyl alcohol (PVA) as surfactants. The synthesis conditions were optimized as follows: pH of 8, molar ratio of ascorbic acid (AA) to silver nitrate (AgNO3) at 0.75, AgNO3 concentration of 5 g·L−1, mass ratio of AC to PVA at 0.05, and mass ratio of PVA to AgNO3 at 0.1. Under the optimal conditions, the median particle size of the prepared silver particles was 0.52 μm, with an average size of 0.49 μm. The particle size distribution was narrow, and the particles exhibited a smooth surface with excellent dispersion characteristics.

Hepatic insulin resistance and muscle insulin resistance are characterized by distinct postprandial plasma metabolite profiles: a cross-sectional study

BackgroundTissue-specific insulin resistance (IR) predominantly in muscle (muscle IR) or liver (liver IR) has previously been linked to distinct fasting metabolite profiles, but postprandial metabolite profiles have not been investigated in tissue-specific IR yet. Given the importance of postprandial metabolic impairments in the pathophysiology of cardiometabolic diseases, we compared postprandial plasma metabolite profiles in response to a high-fat mixed meal between individuals with predominant muscle IR or liver IR.MethodsThis cross-sectional study included data from 214 women and men with BMI 25–40 kg/m2, aged 40–75 years, and with predominant muscle IR or liver IR. Tissue-specific IR was assessed using the muscle insulin sensitivity index (MISI) and hepatic insulin resistance index (HIRI), which were calculated from the glucose and insulin responses during a 7-point oral glucose tolerance test. Plasma samples were collected before (T = 0) and after (T = 30, 60, 120, 240 min) consumption of a high-fat mixed meal and 247 metabolite measures, including lipoproteins, cholesterol, triacylglycerol (TAG), ketone bodies, and amino acids, were quantified using nuclear magnetic resonance spectroscopy. Differences in postprandial plasma metabolite iAUCs between muscle and liver IR were tested using ANCOVA with adjustment for age, sex, center, BMI, and waist-to-hip ratio. P-values were adjusted for a false discovery rate (FDR) of 0.05 using the Benjamini–Hochberg method.ResultsSixty-eight postprandial metabolite iAUCs were significantly different between liver and muscle IR. Liver IR was characterized by greater plasma iAUCs of large VLDL (p = 0.004), very large VLDL (p = 0.002), and medium-sized LDL particles (p = 0.026), and by greater iAUCs of TAG in small VLDL (p = 0.025), large VLDL (p = 0.003), very large VLDL (p = 0.002), all LDL subclasses (all p < 0.05), and small HDL particles (p = 0.011), compared to muscle IR. In liver IR, the postprandial plasma fatty acid (FA) profile consisted of a higher percentage of saturated FA (p = 0.013), and a lower percentage of polyunsaturated FA (p = 0.008), compared to muscle IR.ConclusionPeople with muscle IR or liver IR have distinct postprandial plasma metabolite profiles, with more unfavorable postprandial metabolite responses in those with liver IR compared to muscle IR.

Shear Strength and Consolidation Behaviour of Kaolin Clay Reinforced with a Granular Column Backfilled with Crushed Waste Glass

Granular columns are commonly used for ground improvement. However, minimal research is presently available on the effect of backfill particle size on the geotechnical performance of granular column-reinforced soil. Geo-environmentally, using crushed waste glass (CWG) as a sustainable replacement for depleting traditional construction sands could offer a cleaner feedstock to backfill granular columns while helping recycle growing stockpiles of waste glass, potentially supporting the circular economy transition and decarbonisation of the construction industry. Given these multi-pronged motivations, this study investigated the shear strength and consolidation behaviour of kaolin reinforced with a CWG granular column. Three different particle size ranges (PSR) of CWG were discretely used to install a granular column in the kaolin bed, including fine (0.50–1.0 mm), medium (1.0–1.7 mm) and coarse (1.7–3.35 mm) particles with median particle sizes of 0.78 mm, 1.42 mm and 2.30 mm, respectively. The geocomposite containing a medium CWG column showed the highest increase in friction angle, increasing from 14.0° for kaolin only specimens to 20.7° for the geocomposites. Similarly, the consolidation behaviour of reinforced kaolin (geocomposites) was typically superior to that of kaolin only specimens. Notably, installing a coarse, medium or fine CWG column decreased the average compression index (Cc) of the geocomposites by almost 17%, 35% or 50%, respectively, compared to that of the kaolin only specimens. Given the promising results of this initial study, some suggestions are provided for future studies on assessing the application of CWG as an alternative backfill and sustainable geomaterial in granular column construction.Video abstractThis internationally-partnered Video highlights the findings of the research study, indicating that crushed waste glass (CWG) could potentially serve as a sustainable geomaterial and be used as a replacement for traditional construction sand to backfill granular columns in clayey soils for ground improvement, helping reduce the unsustainable exploitation of sand resources and increasing waste glass recycling, potentially supporting the paradigm shift to a circular economy and contributing to decarbonisation of the construction industry.EwdaqE4KyyTKvkX4_pnUt6Supplementary material 1 (MP4 3737519 kb)

The role of fines in espresso extraction dynamics

The impact of particle size distribution of coffee grounds on espresso extraction was explored. Finely ground coffee for espresso has a characteristically bimodal particle size distribution. For a given median grind size, different grinding technologies can yield a different share of fines (particles < 100 µm). We performed espresso extractions for a range of median particle sizes and systematically varying the share of fines by adding sieved fines to the coffee grounds. Dynamic beverage weights, extraction percentage, extraction time and dynamic headspace PTR-MS (proton-transfer mass spectrometer) analysis and sensory evaluation of the resulting brews were measured. We show that the share of fines plays a key role in the espresso extraction flow rate. An increase of share of fines decreases coffee bed permeability, leads to reduced flow rates and longer extraction times. A statistical model using partial least squares regression of the particle size distributions of coffee grounds confirms that fines decrease the coffee bed permeability. The PTR-MS analysis shows a non-linear increase of aroma compounds in the cup with increasing extraction yield. Our hypothesis is that both extraction efficiency and post-extraction evaporative losses of aroma compounds influence the final aroma compound concentrations in the cup.

Design and evaluation of a calibration system for portable motor vehicle emission particle number detectors

The supervision of the number concentration of particles emitted from motor vehicles is becoming increasingly strict. The regular calibration of portable particle number (PN) detectors is a prerequisite to ensure the effective supervision of PN. At present, the calibration of PN detectors is mostly completed in the laboratory. However, due to the complexity and poor portability of the laboratory calibration system, it is difficult to use this system for the on-site calibration of PN detectors. To this end, a portable motor vehicle emission PN detector calibration system based on the principles of negative pressure siphon atomization, differential electrical mobility classifier, and fA-level weak current measurement was developed, which could quickly and accurately calibrate the PN detector on-site. The system consists of three parts: an atomizer generator, a plate differential mobility analyzer (PDMA), and an aerosol electrometer. The atomizer generator produces NaCl particles with a median particle size of 70 nm and fluctuation of <10%. The particle size classification deviation of the PDMA is <3.7% and the counting error of the aerosol electrometer is <10%. The On-board Emissions Measurement System was calibrated as a PN detector on a self-developed portable calibration system as well as on a laboratory calibration system. The comparison results showed that the measurement results of the portable calibration system were closer to the instrument factory report certificate results, and the maximum error did not exceed 6.72%.

Effects of root traits on soil detachment capacity driven by farmland abandonment

Vegetation restoration significantly affected root traits during farmland abandonment, thereby considerably altering the soil detachment process. However, few studies have investigated the effects of root traits on soil detachment capacity under different ages of farmland abandonment. To examine the effects of root trait changes caused by vegetation restoration on soil detachment capacity by overland flow (Dc) and soil resistance to erosion under different ages of farmland abandonment, flow scouring tests under five shear stress levels (2.80–12.95 Pa) were conducted on 125 undisturbed soil samples collected using an indoor variable slope flume. The results showed that, compared to slope farmland, the root traits of abandoned farmland (5, 12, 24, and 36 years) increased considerably, and the Dc and erodibility decreased by 51.3–93.9 % and 61.8–94.1 %, respectively. The critical shear stress of abandoned farmland gradually increased with the age of farmland abandonment, but remained less than that of slope farmland. Among hydraulic parameters, stream power was the optimal index for predicting Dc, while among root morphological traits, root surface area density (RSAD) was the best indicator for predicting Dc. The median soil particle size (D50) and cohesion are important factors that affect soil detachment. According to the Water Erosion Prediction Project (WEPP) model, Dc can be predicted using the RSAD and soil cohesion (R2 = 0.95, NSE = 0.95). In addition, a new model was established to estimate the soil detachment capacity based on D50 (R2 = 0.97, NSE = 0.97). In the present study, the performance of the model was improved compared with that of previous studies.

Evaluating the Impact of Various Treatment Modalities on the Chewing Efficiency of Anterior Disc Displacements of Temporomandibular Joint Disorder Cases: A Comparative Study.

Internal disc displacement of the temporomandibular joint (TMJ) is identified by an anomaly between the condylar-disc assembly, which, in many cases, may lead to discomfort and malfunction of the chewing function. The study's objective was to assess the effects of four distinct treatment approaches on temporomandibular disorder cases with anterior disc displacements focusing on their chewing efficiency. One hundred participants suffering from reducible TMJ disc displacement were selected for enrollment in the study. Subjects were divided equally into four groups: group I patients were treated with behavioral therapy; group II patients were treated with low-level laser therapy (LLLT); group III patients were treated with anterior repositioning splints; and group IV patients were treated with flat plane splints. Chewing efficiency was assessed utilizing the fractional sieving method and a synthetic food substitute was created using silicon impression material. The statistical analysis encompassed comparisons of chewing efficiency between groups and between baseline and posttreatment within each group, employing analysis of variance (ANOVA) and paired t tests, respectively. Using the paired t test, a significant difference in chewing efficiency values as expressed by the median particle size was observed between the baseline and 6-month values in all groups (P < 0.05), except for group I where no significant change was noted over the 6 months (P > 0.05). The one-way ANOVA test revealed a statistically significant difference among groups following therapies (P ˂ 0.05). The post hoc Tukey test was employed for pairwise comparisons and revealed statistically significant variances in the main values of chewing efficiency among all groups at a 95% confidence level (P ˂ 0.05). The study's results suggest that occlusal splints and LLLT are more effective in improving chewing efficiency than behavioral interventions.

Impact of discontinuous grain size distributions on the spectral energy distribution of debris disks

Context. The collisional evolution of debris disks is expected to cause the characteristic wavy pattern, that is, an under- or overabundance of particles of specific sizes, of grain size distributions. This perturbed grain size distribution potentially leaves characteristic patterns in the spectral energy distribution (SED) of the disk system. Aims. We aim to quantify and understand the specific influence of discontinuous particle size distributions on the appearance of debris disks. For this purpose, we considered dust emission models based on two different grain size distributions, namely, one with a single power law and one with a broken power law. In particular, our study is focused on the impact of an overabundance of small grains and an underabundance of medium-sized grains on the far-IR and (sub-)millimeter regime on the dust reemission radiation and the potential to constrain discontinuities in the grain size distribution from (sub-)millimeter photometric measurements of debris disks. Methods. We compared the spectral index α (Fν ∝ να) in the case of a continuous grain size distribution with that of a discontinuous grain size distribution. We performed this comparison for central stars with different spectral types and two different disk structures (e.g., slim and broad debris dust rings). Results. Within the considered parameter space, we found a characteristic difference between the spectral slopes of the SED in the different scenarios. In particular, the overabundance of small grains resulting from collisional events and thus parameters defining the outcome of disk events in debris disks is potentially observable by comparison with the SED corresponding to a grain size distribution resulting from an ideal collisional cascade. More specifically, the overabundance of small grains leads to a steeper slope in the far-IR and sub-millimeter regime, while the spectral index in the millimeter regime is hardly affected. On the other hand, the underabundance of medium-sized grains results in a slight steepening of the far-IR slope of the SED, but its primary effect is on the millimeter slope of the SED, causing it to become shallower. We also found that the impact of an overabundance of small dust particles is more pronounced than that of an underabundance of medium-sized dust particles. We also found that the difference between the spectral indices for the two different grain size distributions is largest for debris disks around brighter central stars and broader disks. However, the impact of the considered spatial distributions described by the fractional width of the disk system is weak. Our results also show that the dust composition is not the sole physical mechanism responsible for the spectral inversion observed in the far-IR to millimeter part of the SED of debris disk systems. Furthermore, the location of the spectral break is placed at different wavelength regimes if the grain size distribution is considered as a function of blowout size and stellar type.

Feasibility Analysis of Municipal Wastewater Reinjection Technology

To study the feasibility of using municipal sewage as a reserve water source for oilfield reinjection, the water sample treated by the municipal sewage treatment plant and the produced water of the Chang 2 reservoir were taken as the research objects. Through the analysis of water quality and compatibility, the optimal ratio of reinjection water samples was determined. At the same time, the clay swelling experiment and reservoir damage experiment were carried out. The experimental results show that the salinity of municipal sewage is low, and the content of scale ions is low. When the ratio of produced water to municipal sewage is 7:3, the scale formation amount can reach 42.5 mg.L-1, and when the scale inhibitor is added, the scale formation amount can be reduced to 10.4 mg.L-1. The mixed water sample will not cause clay expansion. Meanwhile, Chang 2 reservoir is moderately weak water sensitive and weak acid sensitive. The oil content, suspended solids content, and median particle size of the mixed water sample during reinjection should be controlled at 5 mg.L-1, 5 mg.L-1, and 5 μm to ensure that the reinjected water sample does not cause damage to the reservoir.

A new method for preparation of RE2(CO3)3 by multi-membrane electroconversion

Preparing rare earth carbonates from rare earth chlorides is a common step in the smelting process for all rare earth ores; however, it produces large amounts of ammoniacal nitrogen wastewater and a chloride-rich precipitate. This study proposes a novel, green and simple process for preparing low-chlorine lanthanum carbonate via a multi-membrane electroconversion approach. The effects of the CO2 flow rate, current density, lanthanum chloride concentration, and electroconversion time on the electroconversion process were systematically explored. Under the optimal process conditions (CO2 flow rate = 0.5 L/min, current density = 25 mA/cm2, LaCl3 concentration = 0.3 mol/L, electroconversion time = 60 min), a current efficiency of 75.77% was obtained, along with a unit energy consumption of 5.44 kW h/kg. X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and laser particle size analysis results indicate that a pure La2(CO3)3·8H2O product is obtained with a median particle size of 6.53 μm and chlorine content of 0.0021%. In addition, scanning electron microscopy and transmission electron microscopy observations indicate that the crystallisation and growth of La2(CO3)3·8H2O conform to the oriented attachment and Ostwald ripening mechanisms. Thus, the proposed multi-membrane electroconversion method provides guidance toward the clean transformation of rare earth chlorides to low-chlorine lanthanum carbonates.

Chewing Side Preference Related to Food Texture and Occlusal Contact Area.

To determine whether food texture affects chewing side preference (CSP) and to investigate the relationship between CSP and masticatory factors, such as occlusal contact area, bite force, and masticatory performance. Forty-seven adults (20 women and 27 men; mean age: 24 years) participated in this study. Three types of food (chewing gum, beef jerky, and peanuts) were provided to assess CSP. Occlusal contact area was measured at various ranges of interocclusal distance, and the bite force was measured. Masticatory performance was assessed according to the median particle size. Asymmetry indices of each measurement were calculated and analyzed using Pearson correlation coefficient (α &#61; .05). The CSP for beef jerky and peanuts were significantly correlated with each other, whereas the CSP for chewing gum was not correlated with other food. The proportion of participants who chewed equally on both sides was higher for chewing gum than for beef jerky. There was a significant correlation between the CSP for beef jerky and occlusal contact area, especially at interocclusal distance ranges of 0 to 89 μm and 0 to 109 μm (r &#61; 0.41). Bite force and masticatory performance were not significantly correlated with CSP. Food texture seemed to affect CSP, and masticatory laterality was greater for tough foods. Moreover, CSP for tough food was closely related to the occlusal contact area at an interocclusal distance level of about 0.1 mm.

Forecasting empirical formula for suspended sediment load prediction at upstream of Al-Kufa barrage, Kufa City, Iraq

Abstract The objective of this study was to predict the suspended sediment load at upstream of the Al Kufa barrage. Ten cross-sections in the upstream region have been identified to collect field measurements. As part of the inquiry, the fluid and hydraulic parameters were measured in the field and sediment samples were collected in sections to develop an empirical formula. These variables included the gravitational constant (g), hydraulic radius (R h), mean velocity (V), median particle size (d 50), river top breadth (B), kinematic viscosity (v), and (ρ) water density. The formula was created using both statistical analysis and dimensional analysis techniques. The results showed that the newly developed formula agreed well between the calculated and observed suspended sediment discharges based on the determination coefficient R 2 of 0.979. There was a very high acceptance between the average sediment discharge from the new formula, equal to 7.365 kg/s, and the average sediment discharge from field measurements (7.142 kg/s).