Bed Material Research Articles

Impact of litter on femur and tibial morphology, bone biomechanics, and leg health parameters in broiler chickens.

In this study effects of three types of beddings on broiler leg health and bone biomechanics were evaluated. A total of 504 male chicks (Ross 308) were randomly placed on three beddings (4 replicates/group; 42 birds/pen), zeolite-added litter (ZL), plastic-grid flooring (PF), and wood shavings (WS). On day 42, chickens were weighed, slaughtered, and samples (bone, muscle, and drumstick) were collected. Bones were subjected to leg health tests, morphometric measurements, biomechanical testing, and ash analysis. Broilers in PF and WS groups showed higher live weight than the ZL group (p<0.001), and the incidence of tibial dyschondroplasia (TD) and varus valgus deformity due to distal bending was significantly higher in PF (p<0.001). Multinomial logistic regression showed that bedding has a significant (p = 0.038) contribution toward the development of TD. Tibial strength (p = 0.040), drumstick width (p = 0.001), and total femur and epiphyseal ash contents (p = 0.044, 0.016) were higher in the ZL group. Chicken live weight was correlated with tibial length and weight (r = 0.762, 0.725). Flooring and the type of bedding material directly affect broiler bone length, strength and leg health. Plastic bedding improves the slaughter weight of chickens on the expense of leg deformities, and zeolite litter improves leg health and bone strength.

Effects of hydrothermal pre-treatment on methane potential of anaerobic digestion sludge cake of cattle manure containing sawdust as bedding materials.

The purpose of this study was to analyze the effect of the hydrothermal pretreatment of anaerobic digestion sludge cake of cattle manure on the solubilization of organic matter and the methane yield in order to improve the anaerobic digestion efficiency of cattle manure collected from the sawdust pens of cattle. Anaerobic digestion sludge cake (ADSC) of cattle manure was thermally pre-treated at 160, 180, 200, and 220°C by the hydrothermal pressure reactor, and the biochemical methane potential of ADSC hydrolysate was analyzed. Methane yield recovered by the hydrothermal pre-treatment of ADCS was estimated based on mass balance. The COD solubilization degree (CODs) of the hydrothermal hydrolysate increased to 63.56, 67.13, 70.07, and 66.14% at the hydrothermal reaction temperatures of 160, 180, 200, and 220 °C, respectively. Considering the VS content obtained after the hydrothermal pretreatment, the methane of 10.2 Nm3/ton-ADSC was recovered from ADSC of 1.0ton, and methane yields of ADSC hydrolysate increased to 15.6, 18.0, 17.4, and 17.2 Nm3/ton-ADSC. Therefore, the optimal hydrothermal reaction temperature that yielded the maximum methane yield was 180 °C based on mass balance, and the methane yield from cattle manure containing sawdust was improved by the hydrothermal pre-treatment of ADSC.

GENOTYPIC CHARACTERIZATION OF SOME PATHOGENIC FUNGI ISOLATED FROM POULTRY AND THEIR SURROUNDINGS

Regarding high morbidity, mortality, and production losses, fungi infections have their importance among infectious illnesses and seem to be one of the main challenges facing poultry producers. This study aims to identify the genotypic characteristics of some fungi isolated from poultry. To reach this end, in El-Gharbia Governorate, Egypt, a total of 210 birds with a history of respiratory distress were randomly selected from a variety of private farms and hatcheries. The birds were sacrificed; tissue pieces were collected. In addition, a total of 87 samples of the poultry surroundings including 40 samples of poultry ration, 14 bedding materials, 4 air samples, and 29 water samples were collected. Using traditional fungal isolation, four fungal species were recovered, namely, Aspergillus niger, Aspergillus flavus, Cladosporium perangustum, and Penicillium chrysogenum. PCR was performed by fungus-specific universal primer pairs (ITS1 and ITS4) to identify and describe the genotype of isolated fungi. All examined isolates' ITS1-5.8SrDNA regions could be amplified. A purified PCR product was sequenced according to the Emerald Amp GT PCR master mix. This was initially performed to establish sequence identity to GenBank accession numbers. The rRNA gene for 5.8 sRNA divides the two ITS sections, which are situated between the 18S and 28S rRNA genes. ITS-1 gene sequence of the isolated Cladosporium perangustum (GeneBank accession number was OM 407392). The Sequence of the ITS-1 of isolated Penicillium chrysogenum (GeneBank accession numbers for studied nucleotide sequences were OM407401; OM407402; OM403685, and OM403686). For the examined nucleotide sequences, the GeneBank accession number for the ITS-1 internal transcribed spacer region of single Aspergillus niger was OM407391. GeneBank accession numbers for the isolated Aspergillus flavus ITS-1 sequence examined nucleotide sequences were OM403676, OM403677, and OM403678. In conclusion, genotypic characterization confirmed the phenotypic traditional fungal identification in the present study. Aspergillus species are the major fungi associated with birds in Egypt farms. The predominantly identified species were Aspergillus flavus and Penicillium chrysogenum.

PHENOTYPIC CHARACTERIZATION OF SOME PATHOGENIC FUNGI ISOLATED FROM POULTRY AND THEIR SURROUNDINGS IN EL–GHARBIA GOVERNORATE, EGYPT

Poultry production is affected by several fungal diseases. Such fungal infection occurs in poultry farms via using a moldy litter, or ingestion of contaminated drinking water or moldy ration. In this study, a total of 210 birds with a history of respiratory distress of different breeds were collected randomly from sporadic different private farms and hatcheries in El–Gharbia Governorate, Egypt. The birds were sacrificed, then a total of 1050 tissue specimens from lung, air sacs, liver, crop and trachea were collected. In addition, 40 samples of poultry ration, 14 bedding materials, 4 air samples and 29 water samples were also collected. The collected samples were cultured on Sabouraud’s agar plates. Macromorphological and micromorphological fungal examinations were performed for phenotypic characterization. Histopathological examinations were also performed using with hematoxylin and eosin stains. Antifungal sensitivity testing was screened using Mueller’s Hinton Agar for studying the susceptibility of the recovered fungal isolates to the most commonly used antifungal drugs in Egypt, namely amphotericin B, clotrimazole, fluconazole, itraconazole, ketoconazole, and nystatin. The obtained results demonstrated that mold isolation was the highest in the collected samples from birds at 36.84%, followed by drinking water (31.57%). The highest incidence of mold isolation was recorded at the lungs of broilers and baladi birds followed by the air sacs. While in saso birds, the highest incidence was at the air sac. Collectively, 97 mold strains were identified from the lung, 74 from the air sacs, 30 from the liver, 61 from the trachea, and 44 from the crop. In addition, 19 mold isolates were recovered from the bird surroundings. Aspergillus niger as well as Penicillium chrysogenum were recovered and showed resistance to ketoconazole, while Cladosporium perangustum was resistant to fluconazole. All of the isolated molds were sensitive to itraconazole and nystatin except A. flavus that was resistant to nystatin. All Aspergillus spp. were resistant to fluconazole except A. niger. In conclusion, Aspergillus spp. was the most associated mold with poultry species and their surroundings in Egypt farms. Itraconazole and nystatin could be applied as proper antifungal drugs the control of for Aspergillus infection in birds.

PREVALENCE OF MULTIDRUG RESISTANT SHIGA TOXIN PRODUCING E. coli IN THE MILK OF CATTLE, BUFFALOES, AND CAMEL

Regarding high morbidity, mortality, and production losses, fungi infections have their importance among infectious illnesses and seem to be one of the main challenges facing poultry producers. This study aims to identify the genotypic characteristics of some fungi isolated from poultry. To reach this end, in El-Gharbia Governorate, Egypt, a total of 210 birds with a history of respiratory distress were randomly selected from a variety of private farms and hatcheries. The birds were sacrificed; tissue pieces were collected. In addition, a total of 87 samples of the poultry surroundings including 40 samples of poultry ration, 14 bedding materials, 4 air samples, and 29 water samples were collected. Using traditional fungal isolation, four fungal species were recovered, namely, Aspergillus niger, Aspergillus flavus, Cladosporium perangustum, and Penicillium chrysogenum. PCR was performed by fungus-specific universal primer pairs (ITS1 and ITS4) to identify and describe the genotype of isolated fungi. All examined isolates' ITS1-5.8SrDNA regions could be amplified. A purified PCR product was sequenced according to the Emerald Amp GT PCR master mix. This was initially performed to establish sequence identity to GenBank accession numbers. The rRNA gene for 5.8 sRNA divides the two ITS sections, which are situated between the 18S and 28S rRNA genes. ITS-1 gene sequence of the isolated Cladosporium perangustum (GeneBank accession number was OM 407392). The Sequence of the ITS-1 of isolated Penicillium chrysogenum (GeneBank accession numbers for studied nucleotide sequences were OM407401; OM407402; OM403685, and OM403686). For the examined nucleotide sequences, the GeneBank accession number for the ITS-1 internal transcribed spacer region of single Aspergillus niger was OM407391. GeneBank accession numbers for the isolated Aspergillus flavus ITS-1 sequence examined nucleotide sequences were OM403676, OM403677, and OM403678. In conclusion, genotypic characterization confirmed the phenotypic traditional fungal identification in the present study. Aspergillus species are the major fungi associated with birds in Egypt farms. The predominantly identified species were Aspergillus flavus and Penicillium chrysogenum. Key words: phenotypic; genotypic; molecular; fungi; poultry

Effects of Different Bedding Materials on Production Performance, Lying Behavior and Welfare of Dairy Buffaloes.

Different bedding materials have important effects on the behavioristics, production performance and welfare of buffalo. This study aimed to compare the effects of two bedding materials on lying behavior, production performance and animal welfare of dairy buffaloes. More than 40 multiparous lactating buffaloes were randomly divided into two groups, which were raised on fermented manure bedding (FMB) and chaff bedding (CB). The results showed that the application of FMB improved the lying behavior of buffaloes, the average daily lying time (ADLT) of buffaloes in FMB increased by 58 min compared to those in CB, with a significant difference (p < 0.05); the average daily standing time (ADST) decreased by 30 min, with a significant difference (p < 0.05); and the buffalo comfort index (BCI) increased, but the difference was not significant (p > 0.05). The average daily milk yield of buffaloes in FMB increased by 5.78% compared to buffaloes in CB. The application of FMB improved the hygiene of buffaloes. The locomotion score and hock lesion score were not significantly different between the two groups and all buffaloes did not show moderate and severe lameness. The price of FMB was calculated to be 46% of CB, which greatly reduced the cost of bedding material. In summary, FMB has significantly improved the lying behavior, production performance and welfare of buffaloes and significantly reduce the cost of bedding material.

Experimental investigation on the separated gasification chemical looping combustion performance of phytoremediation plant and retention of heavy metals

Phytoremediation technology has been one of the important ways to treat soil heavy metal contaminant. However, if the harvested phytoremediation plant cannot be properly disposed, the heavy metals in phytoremediation plant may pollute the environment again. Separated gasification chemical looping combustion (SG-CLC) of phytoremediation plant is investigated in a two-stage reactor to reduce the emission of heavy metals into gas. And this technology has the superiority of traditional chemical looping combustion (CLC). The first-stage reactor temperature, bed material and steam mass flow are changed to investigate their effects on the combustion performance, retention of heavy metals in bottom residue and characteristics of oxygen carrier. Five redox experiment cycles are carried out under each condition. Results show that increasing the temperature from 450℃ to 650 ℃, the carbon conversion increases from 44.4% to 66.7%, and the retention rates of Mn, Ni, Zn and Pb decrease from 44.16%, 69.82%, 73.42% and 49.46% to 18.86%, 13.56%, 38.42% and 6.18% respectively. Increasing steam mass flow and using CaO as bed material are also beneficial to enhance the carbon conversion. This also affects the microscopic morphology of oxygen carrier in second-stage reactor. There appears obvious granular morphology on the surface of used oxygen carrier at 650 °C or using CaO as bed material. Rising the flowrate of steam from 0.36 g/min to 0.60 g/min has divergent effects on retention of heavy metals as retention rates of Mn, Ni, Zn and Pb change from 24.87%, 10.42%, 57.32% and 25.06% to 22.32%, 17.70%, 50.97% and 21.38%.

Effects of collars on local scour around semi-circular end bridge abutments

The occurrence of scour around bridge elements due to the transportation of bed material during flood events can cause serious structural damage and loss of life. Increased uncertainties in precipitation and runoff predictions due to climate change make this phenomenon more complex and dangerous. Bridge scour countermeasures should thus be more focused on decreasing scour formation around bridge elements. In this study, abutment scour under clear-water conditions with constant flow intensity was conducted and collars were tested as scour countermeasures around semi-circular end bridge abutments. The experimental study was performed in a rectangular channel with an almost uniform cohesionless bed material for 3 h with and without collars. Collars of various lengths located at different elevations around the abutments were tested to investigate the effect of collars on scour development. The results of the study showed that the scour depth decreased with increasing collar width and when the collar was placed below the bed level for a given abutment length. The results were compared with those of similar earlier studies to show the effect of abutment shape, size of the bed sediment and test durations on the development of scour depth around abutments.

Coarse sediment mobility and fluxes in wide mountain streams: Insights using the virtual velocity approach

The investigation of coarse sediment transport in wide mountain streams is very challenging because of limitations that affect the adoption of direct and indirect field monitoring techniques. Such river type represents then a stream typology for which quantitative knowledge of coarse sediment mobility, dynamics and fluxes is poor. This study uses tracer particles and a virtual velocity approach to gain insights about sediment mobility and coarse bed material transport in a wide mountain stream. Monitoring at the study area was conducted by tagging two types of tracer clasts, installing scour chains, and collecting data on water levels, transport processes, particle travel distances, and active layers over a period of 19 months and five transporting floods in the Tegnas Torrent (the Dolomites, Italy). Bed sediment was mobilized during a limited number of hydrological events (i.e. 6 to 9 per year), taking place in 50 to 400 h and inducing a total coarse sediment flux of about 1200 to 1400 m3 yr−1. The mobilization of coarse particles forming the streambed begins in response to a dimensionless shear stress (τ*c = 0.018) that is lower than thresholds commonly reported in the literature for mountain rivers and the estimated unit bed material transport was remarkably higher compared with those obtained in other mountain streams or gravel-bed rivers. The high mobility of streambed material can be related to the availability of fresh and unstructured sediment transported and deposited in the active channel by a high-magnitude event that occurred a few months before monitoring was conducted in this work, suggesting that sediment fluxes in a stream recently affected by a large flood could be considerably higher than those normally expected in a specific context. Finally, despite the existence of some application constraints, the experiment generated satisfactory results as regards the applicability of the virtual velocity approach in investigations of this stream type. This new quantitative knowledge of sediment fluxes and dynamics is also crucial for management of wide mountain streams.

Desulfurization in co-firing of sewage sludge and wooden biomass in a bubbling fluidized bed combustor under air and oxy-fuel conditions

This work presents results of an experimental investigation of a direct addition of Ca-based sorbent for SO2 capture in a bubbling fluidized bed combustion. The fuel of interest was secondary biomass represented by a dried sewage sludge, which was mixed with primary biomass represented by wooden pellets in a weight ratio of 30:70. The performance of this SO2 capture approach is compared in air and oxy-fuel combustion conditions, since the different gas environment in the bed significantly affects the SO2 capture process. The experiments were carried out in an experimental bubbling fluidized bed combustor with a power load of about 30 kW.Sewage sludge is typical for its high ash content and has sufficient dimensions and attrition resistance to create the fluidized bed without the support of external bed materials. However, it typically consists of S-containing organic substances, resulting in the presence of SOX in the off-gas. A reference case was initially conducted without any sorbent addition in order to investigate the effect of sulfur self-retention in the fuel ash. The sulfur retention in the ash reached almost 45 % in air- and up to 55 % under oxy-combustion.In the next phase, the performance of Ca-based sorbents in sulfur capture was evaluated. The sorbents were represented by two types of limestone with diverse CaCO3 content produced at different locations. The experiments were carried out with three Ca/S mole ratios (1.5, 3, and 4.5). The effect of the fluidized bed temperature was also investigated as the most important parameter.The SO2 capture ratio (used as a performance indicator) was calculated based on emission factors, due to the different specific volumes of flue gas in the air and oxy-fuel modes. The results show in general a significantly higher SO2 capture ratio under oxy-fuel conditions. The differences are more significant in lower Ca/S ratios, where the SO2 capture ratio increased from 46 % under air conditions to 75 % under oxy-fuel for Ca/S = 1.5. In the case of the highest Ca/S ratio examined (Ca/S = 4.5), the increase in SO2 capture was from 90 % to 95 %.

Towards a novel method for detecting atypical lying down and standing up behaviors in dairy cows using accelerometers and machine learning

Free-stall cubicles are designed so that cows do not defecate in the bedding material, while still providing comfortable lying places. However, fixed cubicle elements, such as the partition and neck rail, restrict available movement space and may hinder cows from performing natural lying down and standing up movement patterns. Although there are various types of cubicle partitions that differ in shape, dimensions, or materials, there is no method other than visual observations to assess their effects on cow welfare. An automated detection system could improve the efficiency and promote objectivity of such assessments. Therefore, the aim of this research was to explore which atypical lying down and standing up behaviors could be detected using body-mounted accelerometers and machine learning. Three leg- and one head-mounted accelerometer set to record at 20 Hz were fitted to 48 lactating dairy cows (Brown Swiss and Holstein × Swiss Fleckvieh). Lying down and standing up events were simultaneously assessed through video observations, by assigning binary presence/absence labels for atypical behaviors, such as lunging the head sideways when standing up and pawing the bedding material before lying down. Different time series classification algorithms were employed for model development using a nested cross-validation strategy. The best performing classifiers were MiniRocket and the deep learning algorithm InceptionTime. Atypical behaviors performed during standing up events, namely Hesitant head lunge and Crawling backwards, were identified as most promising candidates for accelerometer-based detection. These behaviors were detected with balanced accuracies of 0.67 and 0.74, respectively, and their learning curves indicated that more training data might further improve model performance. Overall, achieved performances were not yet satisfactory for application in the evaluation of new dairy cow housing installations. Potentially, ethograms designed for human observers are not optimal for machine learning and adjustments with machine learnability in mind might be necessary. The behaviors identified as promising are good candidates for further development into an efficient and objective method that could complement human observations in the assessment of dairy cow housing installations.

A virtual stylus method for non-destructive roughness profile measurement of additive manufactured lattice structures

Surface roughness is traditionally evaluated with contact profilometry; however, these methods are not compatible with complex additive manufactured lattice structures due to limited physical access. For these scenarios, computed tomography (CT) is often used to provide qualitative insight into surface roughness but does not directly yield roughness profile data. This research describes a hybrid approach for the non-destructive quantification of roughness profile data for lattice structures based on the mathematical reconstruction and interpretation of CT data. Formal analyses are applied to propose the theoretical minimum CT voxel size required to characterise surface roughness for a specified sampling length. The method is verified against optical data for nominally flat metallic specimens and applied to metallic and polymeric cylinders fabricated by powder bed fusion and material extrusion respectively. This research also assesses the influence of CT reconstruction thresholding as a process variable and finds that roughness profile data is only weakly influenced by thresholding settings, due to scattering effects at the surface — a novel finding that provides certainty for the industrial application of this method. The ability of the proposed method to accurately characterise the inherent surface roughness of these processes as well as the effect of specimen orientation is thus demonstrated, enabling full geometric characterisation supporting subsequent certification analysis. The method can be algorithmically implemented in combination with the generative design of complex lattice structures to support structural certification requirements.

16S rDNA High Throughput Sequencing Bacterial Diversity Analysis of Cow Mastitis

Background: Bacterial mastitis in cows is a huge challenge to the dairy cattle breeding and production industry. This study examined the relationship between mastitis and bacterial diversity at different sampling sites in dairy farms. Methods: High-throughput sequencing of 16S rRNA V4 region was used to analyze the abundance and diversity of bacterial population sampled from seven different sites in a dairy farm, named healthy cow milk (N), cow milk from a mastitis cow (C), perimammary (T), milk collecting cup (B), turntable surface (P), feces (F) and bedding material (W). Result: In total, 2757356 reads were obtained from the sequencing results, which were annotated to 29 phyla, 67 classes, 166 orders, 295 families, 696 genera and 306 species. In all samples, Proteobacteria and Firmicutes were the dominant microflora, while Oscillospira-UCG-005 and Atopostipes were the dominant genera in different proportions, indicating certain differences in bacterial flora structure among different samples. Furthermore, alpha diversity analysis revealed high richness and diversity among different samples.

Syngas Quality in Fluidized Bed Gasification of Biomass: Comparison between Olivine and K-Feldspar as Bed Materials

The relevance of selecting an appropriate bed material in fluidized bed gasification is a crucial aspect that is often underestimated. The ideal material should be economical, resistant to high temperatures and have small chemical interaction with biomass. However, often only the first of such three aspects is considered, neglecting the biomass–bed interaction effects that develop at high temperatures. In this work, olivine and K-feldspar were upscale-tested in a prototype fluidized bed gasifier (FBG) using arboreal biomass (almond shells). The produced syngas in the two different tests was characterized and compared in terms of composition (H2, CH4, CO, CO2, O2) and fate of contaminants such as volatile organic compounds (VOCs), tar and metals.. Moreover, the composition of olivine and K-feldspar before and after the biomass gasification process has been characterized. The aim of this work is to show which advantages and disadvantages there are in choosing the most suitable material and to optimize the biomass gasification process by reducing the undesirable effects, such as heavy metal production, bed agglomeration and tar production, which are harmful when syngas is used in internal combustion engines (ICE). It has been observed that metals, such as Ni, Cu, Zn, Cd, Sn, Ba and Pb, have higher concentrations in the syngas produced by using olivine as bed material rather than K-feldspar. In particular, heavy metals, such as Pb, Cu, Cd, Ni and Zn, show concentrations of 61.06 mg/Nm3, 15.29 mg/Nm3, 17.97 mg/Nm3, 37.29 mg/Nm3 and 116.39 mg/Nm3, respectively, compared to 23.26 mg/Nm3, 11.82 mg/Nm3, 2.76 mg/Nm3, 24.46 mg/Nm3 and 53.07 mg/Nm3 detected with K-feldspar. Moreover, a more hydrogen-rich syngas when using K-feldspar was produced (46% compared to 39% with olivine).

Spatial patterns of transport‐effective flow at three small confluences: Relation to channel morphology

AbstractThe spatial patterns of transport‐effective flows at confluences and the relation of these patterns to channel morphology remain poorly understood. This field study uses acoustic Doppler current profiler measurements to explore the spatial structure of different transport‐effective flows at three small stream confluences where measurements of flow structure have been obtained previously using electromagnetic current meters or acoustic Doppler velocimeters for events incapable of mobilizing bed material or for transport‐effective events with much smaller discharges. Results show that flow accelerates from upstream to downstream for all six measured flows and that in each case a distinct region of velocity deficit exists within the confluence. Accelerating flow within this velocity‐deficit region eventually transforms into the high‐velocity core of flow downstream of the confluence. Patterns of secondary flow are indicative of helical motion, with some helical cells exhibiting senses of rotation inconsistent with patterns of streamline curvature defined by patterns of depth‐averaged velocity vectors—a type of fluid motion that contrasts with flow structure documented at lower stages. Channel form, especially bed morphology, generally reflects acceleration of flow at the confluences; all three sites exhibit zones of scour. Despite mobility of bed material during measured flows, channel morphology does not change substantially at any of the sites, but systematic change in channel form for two different transport‐effective events with different momentum flux ratios is observed at one of the three confluences. At this confluence, the type of change documented during the two events is consistent with previous work on changes in morphology before and after events with different momentum flux ratios. The results of this study improve understanding of the connections between flow structure and channel form at small lowland stream confluences.

New unsaturated erosion model for landslide: Effects of flow particle size and debunking the importance of frictional stress

Flow-type landslides, such as debris flows and rock avalanches, erode soil bed material as they flow downslope. The eroded material increases the volume of a landslide, and thus, its destructive potential. Field reports of debris flow show that collisional stresses generally occur at the flow front while frictional stresses generally occur at the base of the flow body. However, it remains unclear which of these competing effects is more dominant in terms of soil bed erosion. Moreover, existing theories do not consider the flow basal slip condition on the erosion dynamics at the flow-bed interface, nor do they consider the effects of volumetric response on the shear strength of unsaturated soil beds. In this study, an erosion model that considers the effects of basal slip condition and the volumetric response of unsaturated soil beds is proposed and evaluated with a unique set of experiments. Boundary collisional stresses drive soil bed erosion, while boundary frictional shear stresses are counteracted by the soil strength mobilized by overburden induced by volume contraction. The flow particle size and Froude number are shown to be adequate indicators of the boundary collisional stresses that govern the soil bed erosion rate. Findings from this study hint at the conjecture that existing erosion models may not be equipped with the necessary physics to provide realistic hazard assessments of flow-type landslides eroding soil beds.

Magnetic properties of ilmenite used for oxygen carrier aided combustion

Oxygen carrier aided combustion is a combustion process that utilizes oxygen carrying particles in a fluidized bed to transport oxygen from oxygen-rich to oxygen-poor regions in the reactor. A commonly used oxygen-carrying material is ilmenite (FeTiO3) which is a naturally occurring mineral. At higher oxygen partial pressures ilmenite can react to pseudobrookite (Fe2TiO5) and thereby take up oxygen. Upon reduction of pseudobrookite in oxygen-lean locations the oxygen is released, which enhances the distribution of oxygen through the reactor.Ilmenite was used as bed material in an industrial 115 MWth circulating fluidized bed (CFB) boiler where recycled waste wood and wood chips were utilized as fuel. Bottom ash samples were extracted after one and two weeks and the samples were separated into two fractions by a magnetic separator. The magnetic fraction was expected to be enriched in iron-containing oxides and was therefore aimed to be recirculated into the boiler.The SEM-EDS analysis revealed that the non-magnetic fraction consists to the largest extent of feldspar (KAlSi3O8) particles. A significant amount of freshly introduced ilmenite particles was also classified as non-magnetic by the magnetic separator. Characteristic for these particles was a lack of ash layer, suggesting they had only recently been added to the system. In the magnetic fraction, several feldspar particles were found which were covered by a layer rich in Ca, Fe, Ti, and Si. Comparing the XRD analysis of the ash prior to magnetic separation with its magnetic fraction revealed a decrease of the peaks corresponding to feldspar. The removal of feldspar particles by magnetic separation was further corroborated by XRF analysis, where the concentration of K, Al and Si was significantly higher in the non-magnetic fraction, however, no changes were observed in the concentration of Fe. The present analyses shows that prolonged exposure time of ilmenite increases its magnetic susceptibility. Non-magnetic feldspar was shown to acquire significant magnetic susceptibility by formation of a surface layer containing Fe-rich attrition products from ilmenite.

Observation of Relationship between Surface Flow Velocity and Mean Velocity

Surface velocity measurement using electromagnetic waves is common in flood season discharge surveys in Korea. In order to expand the relatively safe non-contact discharge survey, this study investigated the reliability of the coefficient that converts surface velocity to mean velocity in rivers and waterways. Surface and mean velocity were investigated for agricultural reservoir spillways, gravel rivers, and irrigation canals, and the volumetric capacity of agricultural reservoirs was confirmed. As a result of the investigation, the mean velocity conversion coefficients according to the riverbed slope or riverbed material were very diverse, such as 0.61, 0.90, 0.52, and 0.88. The above result makes it clear that each investigation point has a unique conversion coefficient according to the characteristics of the bed material. In other words, accurate discharge investigation is possible by knowing the unique conversion factor to each point. The importance of water management due to climate change is increasing day by day. Accurate flow rate for rivers and waterways will be used as an essential factor for quantitative water resource management in the future.

Monitoring of bed material in a biomass fluidized bed boiler using an electronic tongue

The thermal conversion of biomass fuel mixes in fluidized beds can cause agglomeration. To counteract agglomeration, bed material is gradually exchanged with virgin bed material, and this results in increased disposal of used bed material. Furthermore, the bed material exchange represents a costly option, as it involves a cost for virgin bed material, for landfill, and for unplanned downtime of the plant.This paper presents a novel method for the evaluation of bed material quality: the electronic tongue (ET). Evaluation of bed material quality can contribute toward decreasing the cost of unnecessary exchanges of bed material. The proposed method was tested on bed material sampled on an almost daily basis from a commercial fluidized bed boiler during several months of operation.A two-electrode ET was used for the evaluation of the bed material quality. The analysis relied on pulsed voltammetry measurements and multivariate data analysis with Principal Component Analysis (PCA). The results suggest that it is possible to follow bed material changes and that the ET, after further development, may be used to optimize the material flows connected to the bed material. Further research is being conducted to optimize the ET’s performance and its application in monitoring bed material.

Ecologically Engineered Systems for Treating Agriculture Runoff by Integrating “Wastes” into Constructed Wetlands

Runoff from agricultural irrigation is contaminated and loaded with pesticides. Frequent toxic levels of pesticide detection in the ecosystem motivate scientists and engineers to diminish agro-chemicals flowing into the environment. Constructed wetland, CWs, treatments are a sustainable methodology of special interest since it possess a symbiosis value. Flytek (FT) pesticide use has increased at an unprecedented rate for crop production as well as an increase in runoff loaded with Flytek. This study introduces the use of constructed wetlands based on an alum- sludge substrate for the purpose of Flytek (FT) removal performance. The system is based on an adsorption column and a sludge cake coupled with gravel acting as a carrier in order to be an adsorption bed and filtration system for Flytek removal. The structure, morphology and characteristics of the adsorption bed material “alum sludge” were characterized using X-ray diffraction spectroscopy and Scanning Electron Microscope (SEM). Additionally, Fourier-Transform infrared spectroscopy (FTIR) was explored. The experimental results revealed that a vertical flow constructed wetland is significant in eliminating the Flytek pesticide. However, the amount and height of sludge in a wetlands column affects its removal efficiency with the optimal removal (96%) being linked to the presence of sludge in 80%. Moreover, temperature, pH and the FT load showed a significant effect in removals, with the optimal operating conditions being recorded at 7.2 pH, 26 °C and 100 ppm of FT. The kinetic modeling is also investigated to validate the practical life applications and designs, and the results verified the reaction follows the pseudo 2nd-order reaction kinetic model according to the correlation coefficient factor. Furthermore, according to the isotherm model results the scheme follows the Freundlich isotherm model. Such preliminarily data of a gravel-alum-sludge-adsorption-column scheme is a good indicator in developing a constructed wetland facility being a good candidate for controlling agriculture effluent streams.