Granular Size Research Articles

Red luminescence in europium fluoride – Holmium modified with alanine (EFHA) nanoparticles

Holmium doped EuF3 nanoparticles (EFHA) have been synthesised in presence of alanine using wet chemical method. EFHA nanoparticles belongs to hexagonal phase with a = b = 6.980 Å and c = 7.312 Å. The Debye-Scherer particle size from XRD analysis is 42.79 nm. SEM studies show formation of flakes like structures with granular size of about 14 nm. TEM analysis shows formation of assorted size nanoparticles consisting of hyperboloids, spear shaped structures and globular aggregates. The planes indicated by the SAED pattern remains confirmed from XRD analysis. Multiple peaks below 400 nm in UV –Vis spectra indicate formation of quantum dots. Comparative vibrational analysis of FTIR and FT-Raman has been carried out. PL spectra shows intense peak at 654 nm (red) due to 5D0 → 7F3 transition.

Cake formation and filtration characteristics of a cyclone-granular bed filter

The dust cake is critical to improve the fine particle collection efficiency in the gas-solid separation process of the granular bed filter (GBF). In this work, the dust cake formation and the corresponding filtration characteristics in a cyclone-granular bed filter (C-GBF) were investigated by experiments under a constant-velocity filtering condition. It was found that cake filtration, deep-bed filtration and the corresponding transitional phenomena could be observed in the C-GBF. A critical porosity was defined to identify the transition from cake filtration to deep-bed filtration. A following parametric study showed that a higher filtration gas velocity could increase the critical porosity and made it more difficult to form a dust cake. It was also demonstrated that the critical porosity was little affected by the dust concentration. However, the time point of the transition of different filtration modes was earlier with a higher dust concentration. The inlet gas velocity ultimately resulted in the different dust concentrations into the GBF. The similar dynamic processes of cake formation were obtained for different granular sizes. These results provided a deeper understanding of the dynamic behaviors of cake formation and filtration mode transition, which played an important role in the design and the scaling-up of the C-GBF filtration systems.

CRUSHED LIMESTONE SAND: AN EFFECTIVE ALTERNATIVE TO NATURAL SAND IN CONCRETE

Due to its scarcity and the detrimental environmental effect of its extraction, leading to governmental restrictions, the good quality natural rounded siliceous sand became less available in Lebanon. This national and international issue affects the construction industry through the cost and the quality of concrete. Currently, this sand, too fine to be used alone as fine aggregate in concrete mixes, is always mixed with an appropriate percentage of crushed limestone sand to meet the standard grading. The objective of the study is to assess the feasibility of total replacement of natural rounded siliceous sand by crushed limestone sand to avoid the dependency of the construction field on the quality and availability of this material in the Lebanese context. The research program consists of proposing various concrete mixes without natural sand and verifying, following a performance-based approach, that their behaviors can be maintained, at different ages of hardened states, compared to those of the reference concrete incorporating natural sand. The resulting comparisons allow identifying the influences on compressive and flexural strengths of natural sand substitution and of the variations of granular size distribution. At this stage of the study, some preliminary conclusions about the applicability of the solution of natural sand total substitution are proposed.

Effect of the co-treatment of synthetic faecal sludge and wastewater in an aerobic granular sludge system

The co-treatment of two synthetic faecal sludges (FS-1 and FS-2) with municipal synthetic wastewater (WW) was evaluated in an aerobic granular sludge (AGS) reactor. After characterisation, FS-1 showed the following concentrations, representative for medium-strength FS: 12,180 mg TSS L−1, 24,300 mg total COD L−1, 93.8 mg PO3-P L−1, and 325 mg NH4-N L−1. The NO3-N concentration was relatively high (300 mg L−1). For FS-2, the main difference with FS-1 was a lower nitrate concentration (18 mg L−1). The recipes were added consecutively, together with the WW, to an AGS reactor. In the case of FS-1, the system was fed with 7.2 kg total COD m−3d−1 and 0.5 kg Nitrogen m−3d−1. Undesired denitrification occurred during feeding and settling resulting in floating sludge and wash-out. In the case of FS-2, the system was fed with 8.0 kg total COD m−3d−1 and 0.3 kg Nitrogen m−3d−1. The lower NO3-N concentration in FS-2 resulted in less floating sludge, a more stabilised granular bed and better effluent concentrations. To enhance the hydrolysis of the slowly biodegradable particulates from the synthetic FS, an anaerobic stand-by period was added and the aeration period was increased. Overall, when compared to a control AGS reactor, a lower COD consumption (from 87 to 35 mg g−1 VSS h−1), P-uptake rates (from 6.0 to 2.0 mg P g VSS−1 h−1) and NH4-N removal (from 2.5 to 1.4 mg NH4-N g VSS−1 h−1) were registered after introducing the synthetic FS. Approximately 40% of the granular bed became flocculent at the end of the study, and a reduction of the granular size accompanied by higher solids accumulation in the reactor was observed. A considerable protozoa Vorticella spp. bloom attached to the granules and the accumulated particles occurred; potentially contributing to the removal of the suspended solids which were part of the FS recipe.

Chemiluminescence for rapid detection of free radicals in starch samples

Using the electron paramagnetic resonance (EPR) signal intensity for heat-treated rice starch (RS), a chemiluminescence (CL) method was established for the rapid determination (<40 s) of the free radical content in starch samples. Results showed that the initial CL intensity of hydration for RS samples was significantly correlated with the signal intensity measured using EPR, validating this CL method for detecting RS radicals. This method could also be used to detect free radical content in starches from other sources. It was speculated that the correlation coefficients between two intensities was associated with the differences of crystalline structures and granular sizes among starches. These results provide the possibility that the CL method could be used to detect starch radicals and compensate for the limitations of EPR method to detect free radicals in starch samples with high moisture content.

Anionic nanoparticle and microplastic non-exponential distributions from source scale with grain size in environmental granular media

Nanoparticle and microplastic (colloid) transport behaviors impact strategies for groundwater protection and remediation. Complex colloid transport behaviors of anionic nano- and micro-sized colloids have been previously elucidated via independent experiments in chemically-cleaned and amended granular media with grain sizes in the range of fine to coarse sand (e.g., 200–1000 μm). Such experiments show that under conditions where a repulsive barrier was present in colloid-collector interactions (unfavorable conditions), the distribution of retained colloids down-gradient from their source deviates from the exponential decrease expected from compounded loss across a series of collectors (grains). Previous experiments have not examined the impact of colloid size or granular media grain size on colloid distribution down-gradient from their source, particularly in streambed-equilibrated granular media. To address this gap, a field transport experiment in constructed wetland stream beds to distances up to 20 m were conducted for colloids ranging in size from micro to nano (60 nm–7 μm) in streambed-equilibrated pea gravel and sand (4200 and 420 μm mean grain sizes, respectively). All colloid sizes showed non-exponential (hyper-exponential) distributions from source, over meter scales in pea gravel versus cm scales reported for fine sand. Colloids in the ca. 1 μm size range were most mobile, as expected from mass transfer to surfaces and interaction with nanoscale heterogeneity. The distance over which non-exponential colloid distribution occurred increased with media grain size, which carries implications for the potential mechanism driving non-exponential colloid distribution from source, and for strategies to predict transport.

Characteristics and mechanism of anammox granular sludge with different granule size in high load and low rising velocity sewage treatment

An integrated investigation to structural, activity and microbial diversity of anammox granular sludge (AnGS) in a wastewater treatment system with high ammonia nitrogen load was performed and aimed to establish the relationship between granular size and performance. With the increase in granule size, the main component of extracellular polymeric substances (EPS) changed from slime EPS to tightly-bound EPS, while the organic component remained the same, and the specific anammox activity increased. However, the results of qPCR and high-throughput sequencing showed that for granules with sizes inferior than 4.75 mm, the abundance of ammonia-oxidizing bacteria (AnAOB) increased as the size increased, and the copies of AnAOB decreased when the granule size increased above 4.75 mm, and the community complexity increased. According to the correlation analysis results, AnAOB first accumulated and then optimized the flora structure to improve efficiency and 2.8 mm to 4.75 mm was the optimal size of AnGS.

PERFORMANCE OF COPPER SLAG AS REPLACEMENT OF FINE AGGREGATE WITH DIFFERENT GRADES

Copper slag is the waste material that is generated during the manufacturing process of copper. As per the statistics for manufacturing of one ton copper leads to generation of 2.25 tons of copper slag. Although this material is adopted for different other purposes like land filling and abbrasive tools preparation, low quality tools and railway ballast materials. Inspite of all these application around the world only 18 percent of copper slag is used remaining 82% comes under wastage. but if We adopt the same copper slag material as a replacement of construction material in construction industry as may be full replacement or partial replacement of either cementing material or fine aggregates it will have a promising future. At the same time the remaining 82 % waste copper slag have the added valve in construction industry and at the same time land filling problem will get solve. From past 20 years so many researchers already proved that the the usage of copper slag as a replacement in concrete will possible due to same granular size of copper likely as of fine aggregate. Not only as fine aggregate replacement, the finely grained copper slag powder can also be adopted as partial replacement of cementing material to concrete and in the production of cement lime clinkers There are so many researches are carried around the globe on the usage of copper slag as replacement material, but in India a very few researches are carried. In this particular thesis mainly looked on to generate specific investigation data on the use of copper slag as fine aggregate replacement in partial basis.

Impact of additive application on the establishment of fast and stable aerobic granulation.

Aerobic granular sludge (AGS) is a microbial biofilm self-aggregation, which is effective for nutrient and pollutant removal, through the development of dense microbial layers bound together with extracellular polymeric substances (EPSs). However, long start-up times and granule disintegration are still challenges ahead. An array of external additives, including ion chelating agents, sludge-based enhancers, and magnetic influence have been tested to overcome these barriers. The application of such additives may promote enhanced EPS production, neutralization of charges on the bacterial surface, acts as a core-induced agent, or as a bridge to connect EPSs and cell surfaces. Although additives may improve the granule formation without reducing treatment efficiencies, there are still environmental concerns due to the fate and toxicity of discharged excess sludge. This mini-review identifies an array of external additives and their mechanisms to improve granulation properties, and proposes discussion about the technical and economic viability of these additives. KEY POINTS: • Additives reduce granulation time and repair granule disintegration. • Biopolymer-based additives fulfill technical and environmental requirements. • Sludge-based additives are cheap and in line with the resource recovery concept. • The need for environmental-friendly additives for aerobic granular sludge process. • External additives affect granular biomass size distribution.

Improving the recovery of copper from electric cable waste derived from automotive industry by corona-electrostatic separation

The aim of this work is to demonstrate the possibility of using electric field forces for the recovery of copper from a fine PVC/Cu granular mixture of low metal content (less than 15%), obtained as “PVC fraction” in the recycling process of electric cable waste from automotive industry, using vibrating table technology. Electrostatic separation of copper granules which are “impurities” in the PVC fraction, increased the overall recovery of copper close to 100%. Granular size classification proved to be a very useful operation in the electrostatic separation process of a particular mixture. The −0.63 mm size class contains the majority of the copper granules and the electrostatic separation allows the recovery of up to 95% copper contained in the granular waste, at purity higher than 99.8%. Copper represents less than 1% in the +0.63 mm size class and can also be recovered with high purity by improving the chopping technology of the cable waste, as well as the separation between the copper and the high conductivity rubber granules.

Scanning velocity influence on microstructure evolution and mechanical properties of laser melting deposited 12CrNi2 low alloy steel

12CrNi2 low alloy steels were prepared by laser melting deposition (LMD), aiming at investigating the effect of laser scanning velocity on phase composition, microstructure, microhardness, residual stress and tensile properties of the specimens. Experimental results showed that the α-Fe diffraction peaks in the specimens shifted to lower angle due to the solid solution of ferrite-forming elements. The microstructure of LMD-processed 12CrNi2 alloy steel was mainly composed of ferrite (F) and granular bainite (GB). High microhardness (348 ± 8 HV0.2) and low residual tensile stress (57 ± 5 Mpa) can be achieved by optimizing the laser parameters. As the laser scanning velocity increased, the average granular size was refined and the majority of grains had smaller sizes close to 2–3 μm, which was significantly finer compared with those prepared by conventional process. LMD-processed 12CrNi2 alloy steel exhibited satisfactory mechanical properties with ultimate tensile strength (1000 ± 17 MPa), yield strength (960 ± 12 MPa) and higher elongation (10.02%), which could reach the requirements of low alloy steel components due to the satisfactory strength and toughness.

Measuring multi-spatiotemporal scale tourist destination popularity based on text granular computing.

User-generated content (UGC) is an important data source for tourism GIScience research. However, no effective approach exists for identifying hidden spatiotemporal patterns within multi-scale unstructured UGC. Therefore, we developed an algorithm to measure the tourist destination popularity (TDP) based on a multi-spatiotemporal text granular computing model, called TDPMTGC. To accurately granulate the spatial and temporal information of tourism text, tourism text data granules are used to represent landscape objects. These granules are unified objects that possess multiple attributes, such as spatial and temporal dimensions. The multi-spatiotemporal scales are characterized by the multi-hierarchical structure of granular computing, and transformations of granular layers and data granule size are achieved by scale selection in the spatial and temporal dimensions. Therefore, all scales between the spatial and temporal dimension are related, which allows for the comparability of the data granules of all spatial-spatial, temporal-temporal and spatial-temporal layers. This approach achieves a quantitative description and comparison of the popularity value of granules between adjacent scales and cross-scales. Therefore, the TDP with multi-spatiotemporal scales can be deduced and calculated in a systematic framework. We first introduce the conceptual framework of TDPMTGC to construct a quantitative measurement model of TDP at multi-spatiotemporal scales. Then, we present a dataset construction approach to support multi-spatiotemporal scale granular reorganization. Finally, TDPMTGC is derived to describe both the TDP at a single spatial or temporal scale and the patterns and processes of the TDP at multi-spatiotemporal scales. A case study from Jiuzhaigou shows that the TDP derived using TDPMTGC is consistent with the conclusions of existing studies. More importantly, TDPMTGC provides additional detailed characteristics, such as the contributions of different scenic spots in a tourist route or scenic area, the monthly anomalies and daily contributions of TDP in a specific year, the distinct weakening of tourist route scale in tourist cognition, and the daily variations of TDP during in-season and off-season times. This is the first time that a granular computing model has been introduced to tourism GIScience that provides a feasible scheme for reorganizing large-scale unstructured text and constructing public spatiotemporal UGC tourism datasets. TDPMTGC constitutes a new approach for exploring tourist behaviors and the driving mechanisms of tourism patterns and processes.

Particle Size Dependent Heavy Metals in Road Dusts from Maanshan City, China

In this study the road dusts (RDs) <1,000 μm from Maanshan City, China were characterized from the prospects of size fractionated pollution by heavy metals (HMs). Particulates with size <75 μm, 75–125 μm, 125–250 μm, 250–500 μm and 500–1,000 μm averagely accounted for 35.7±11.7%, 14.6±11.0%, 25.3±12.5%, 11.6±8.8% and 12.8±12.9% of the total weight, respectively. This result implies the gravimetric percentage was overall declined with increasing granular size, following gamma distribution function (p < 0.001). It was observed that the highest contents of Zn, Ni, Pb and Cd occurred with the fine RDs < 75 μm while Cu with these < 125 μm, suggesting HMs preferred to be associated with the fine particulates. Cu, Zn, Ni, Pb, Cr and Cd were present in RDs with bulk contents of 68±30 mg/kg, 285±122 mg/kg, 23±16 mg/kg, 53±21 mg/kg, 432+297 mg/kg and 0.56±0.39 mg/kg, which resulted in geo-accumulation index (lgeo) values as -1.04, 2.35, -2.38, 0.38, 1.54 and 0.18, respectively. Hence, it can be concluded that the RDs had only been significantly polluted by Zn. Person correlation analysis suggests those HMs ubiquitously present in RDs had size-dependent sources.

REDUCTION OF AMMONIA EMISSIONS FROM THE COMPOSTING OF SLAUGHTERHOUSE SOLID WASTE USING ZEOLITE

The process of aerobic composting the slaughterhouse (SH) solid waste generate ammonia emissions. Aim: The objective of this research to study the ability of the adsorbent to use zeolite to reduce ammonia gas emissions during the composting process of SH solid waste. Methodology and Results: Reduction of ammonia emission is conducted during the aerobic composting process which is 50 days. The raw material composition of the composting process used was 100% rumen contents, 60% rumen contents: 40% straw, 50% rumen contents: 50% straw, and 40% rumen contents: 60% straw. Zeolite used in the form of granular size 100 mesh. The result of the research showed that the level of release of ammonia gas emissions during the composting process could be reduced by zeolite. Conclusion, significance, and impact study: The efficiency of reducing ammonia gas emissions using zeolite adsorbents in the composting process of SH solid waste ranges from 98.09 - 99.40% on average. Zeolite is an adsorbent that has high adsorption power because it has many pores and has a high ion exchange high capacity and serves as an absorbent cation that can cause environmental pollution.

Study of the Influence of Annealing Temperature on the Structural Properties for (Ni1-xZnxFe2O4) Compounds

Nikel-Znic ferrites with chemical formula Ni1-xZnxFe2O4 for (x:0.00 , 0.5 and 1) were synthesis by chemical co-precipitation method at various annealing temperatures (27°C,300°C,600°C,900°C, 1200°C) for (4h). The samples were examined via X-ray diffraction patterns. The XRD pattern confirm the formation of face centered cubic structure (fcc) for all samples. The particle size, lattice parameter, theoretical density and porosity were also measured by X-ray diffraction, and bulk density. It is noted that granular particle size increases with increasing annealing temperature, while decreasing lattice constant, theoretical density and porosity with increasing annealing temperature. The homogeneity, regularity, particle size and the roughness of sample surfaces were calculated using atomic power microscope technique.

Use of cellulose acetate butyrate as a carrier for preparation of alcohol-resistant matrix tablet

The objective of this study was to investigate cellulose acetate butyrate (CAB) as a carrier for extended-release alcohol-resistant matrix tablet. Powder blends were either directly compressed or granulated before compression. The drug release from CAB matrix tablet was robust to formulation/process parameters such as compression force (10−20 kN), granular size (0.15−1.40 mm), and drug content (50–70%). In addition, release medium variables such as ionic strength, pH, and agitation rate had no effect on the drug release. CAB matrix tablet was more robust than ethylcellulose matrix tablet; the release from CAB matrix tablet was not affected by ethanol content (up to 20% v/v) in the release medium irrespective of agitation. CAB is a promising polymer for formulating of alcohol-resistant extended-release matrix tablet.

Microstructure and properties of the interlayer heat-affected zone in X80 pipeline girth welds

The heat-affected zone between the layers of a weld metal is a sensitive and important component of girth welds in X80 pipelines. However, only a few studies have focused on the interlayer heat-affected zone (IHAZ). In this work, thermal simulation was conducted to investigate the relationship between IHAZ microstructure and properties. Results showed that the toughness of the weld metal improved after a single welding thermal cycle but decreased after double welding thermal cycles, particularly when the weld metal was subjected to unaltered coarse grains of IHAZ. The relationship between the microstructure and properties of IHAZ was established to present the correlation of toughness with granular bainite content, grain size, and high-angle grain boundary content.

Flexible ferroelectric and magnetic orders in BiFeO3/MnFe2O4 nanocomposites to steer wide range energy and data storage capability

The key phenomena in multiferroic materials are their spontaneous polarization and magnetization. In order to meet the modern needs in the field of information technology and engineering, their coupling has been of great interest for generating marvel applications. Based on this idea, sol–gel auto-combustion method was utilized to synthesize BiFeO3 and MnFe2O4 which were moulded together in a composite by ball milling. For all the calcined samples of (1 − x)Bi0.9La0.1Fe0.9Mn0.1O3-(x)MnFe2O4 with different concentrations of MnFe2O4 i.e. at x = 0.00, 0.30, 0.50, 0.70 and 1.00, XRD was utilized for the analysis of crystal structure. It depicted the rhombohedral structure of BiFeO3 without any phase shifting throughout the samples, except at x = 1.00, for pure MnFe2O4, exhibiting cubic structure with no peak of BiFeO3 involved. Surface morphology was analysed using FESEM which confirmed that the granular size increased with the increase in MnFe2O4 concentration. For finding the weight percentage and elemental composition of the prepared composites, EDX analysis was carried out which revealed the presence of Bi, Mn, Fe, O, La in accordance with their stoichiometric formula. Vibrating sample magnetometry was put into use to inspect the magnetic properties of the synthesized composites and it was found that with the enhancement of MnFe2O4, magnetic characteristics were significantly improved. At last, precision multiferroic tester was used to examine the ferroelectric properties at 10 V. The PE loops, recoverable energy density, energy loss density and energy efficiency revealed a nice ferroelectric response in BiFeO3 dominating compositions. These interesting features uncovered the potential of these compositions for energy storage devices.

Elucidating Hydrothermally Synthesized CNTs-MnO2 Composites through Electrochemical Scrutiny for Wielding Electrodes in Energy Storage

Search of materials with better electrochemical performance is currently one of the key interests around the globe. In this context, the electrochemical characteristics of MnO2/CNTs (manganese dioxide/carbon nanotubes) composites prepared in two simple steps have been reported. X-ray diffraction confirmed the structural purity of the composite contents revealing that the intensity of peaks first decreased and after the addition of more CNTs, the intensity of the peaks started to increase. Scanning electron microscope was utilized to examine the surface morphology of MnO2/CNTs composites which indicated that with increase of CNTs contents, the granular size of MnO2 particles slightly decreased. The conductivity was inspected by electrochemical impedance spectroscopy, which demonstrated that increase in CNTs concentration provided conducting channels for charge transportation. The energy density calculations revealed that maximum energy density was observed for the composition with 0.5% CNTs. These characteristics inferred that the composite material could be utilized as an electrode in electric batteries and energy storage devices.

Attachment and adhesion force between biogas bubbles and anaerobic granular sludge in the up-flow anaerobic sludge blanket

The performance of the up-flow anaerobic sludge blanket (UASB) is significantly governed by the hydrodynamics of the reactor. Though the influence of hydrodynamics on mass transfer, granular size distribution, and biogas production was well studied, the interaction between biogas bubbles and anaerobic granular sludge (AGS) is poorly understood. This study used the impinging-jet technique and bubble probe atomic force microscope (AFM) to investigate the attachment and adhesion force between biogas bubbles (CH4 and CO2) and AGS. The fluxes of normalized CH4 or CO2 bubble-attachment on two kinds of AGS were directly affected by gas velocity and decreased with an increase in the Reynolds number ranged from 40 to 140. The bubble-attachment had a positive linear relationship with the contact angles, ratio of exopolymeric protein and polysaccharide, and hydrophilic functional groups of AGS. A bubble probe AFM was used to explore the adhesion force between a single bubble and AGS. The results indicated that the adhesion force between the bubbles and the two kinds of AGS also decreased with increasing approach velocity. Overall, these results contribute to a new insight into the understanding of interaction between biogas bubbles and AGS in UASB reactors.