Formation Of Depositions Research Articles

Hyperspectral mapping of the response of grapevine cultivars to Plasmopara viticola infection at the tissue scale.

Resistance of grapevine to Plasmopara viticola is associated with the hypersensitive reaction, accumulation of stilbenoids, and formation of callose depositions. Spectral characterization of infected leaf tissue of cvs 'Regent' and 'Solaris' with resistance genes Rpv 3-1 and Rpv 10 and Rpv 3-3, respectively, suggested that resistance is not dependent on large-scale necrotization of host tissue. Reactions of the resistant cultivars and a reference susceptible to P. viticola were studied using hyperspectral imaging (range 400-1000 nm) at the tissue level and microscopic techniques. Resistance of both cultivars was incomplete and allowed pathogen reproduction. Spectral vegetation indices characterized the host response to pathogen invasion; the vitality of infected and necrotic leaf tissue differed significantly. Resistance depended on local accumulation of polyphenols in response to haustorium formation and was more effective for cv. 'Solaris'. Although hypersensitive reaction of some cells prevented colonization of palisade parenchyma, resistance was not associated with extensive necrotization of tissue, and the biotrophic pathogen survived localized death of penetrated host cells. Hyperspectral imaging was suitable to characterize and differentiate the resistance reactions of grapevine cultivars by mapping of the cellular response to pathogen attack on the tissue level and yields useful information on host-pathogen interactions.

A highly operating stability, oxygen reduction reaction active and CO2/Cr tolerance perovskite cathode for solid oxide fuel cells

Layered perovskite-related GdBaFe2O5+δ (GBF) and GdBaFeCoO5+δ (GBFC) oxides are systematically studied as advanced air electrodes for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The characterizations of the samples are gauged with the assistance of a variety of techniques, involving X-ray diffractometer (XRD), O2-temperature programmed desorption (O2-TPD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Fourier transform infrared spectrometry (FT-IR). Results of XRD demonstrate that GBFC has the exact same crystal structure as that of GBF, which displays slight lattice shrinkage. Substitution of Co for Fe increases the TEC from 9.87 × 10−6 K−1 and 16.6 × 10−6 K−1 at 150–700 °C. GBFC shows the highest conductivity of 500 S cm−1 at 520 °C, which complies with the requirement for the cathode of the fuel cell. The polarization resistance (Rp) values of GBF and GBFC are 0.33 Ω cm2 and 0.07 Ω cm2 at 650 °C, respectively. Moreover, a single cell based on Sm0.8Ce0.2O1.9 (SDC) electrolyte-supported is indicative of a peak power density of 0.28 W cm−2 for GBFC cathode at 700 °C. This single cell also exhibits a superior operational stability utilizing dry hydrogen fuel at 600 °C during the tested 220 h. Electrochemical impedance spectroscopy (EIS) and relaxation time distribution (DRT) results are suggestive of the slowly decreasing oxygen reduction kinetics of GBFC cathode with the introduction of CO2 or gaseous Cr species, which may be connected with the formation of carbonate or Cr depositions. Compared to classic materials, GBFC cathode shows very good electrochemical stability and CO2/Cr tolerance.

Numerical study of mist film cooling on a flat plate with various numbers of deposition

An Eulerian-Eulerian multiphase solver of the open-source CFD software Open-Foam was used to numerically compute the film cooling investigation on a flat plate with various numbers of deposition. The analysis was performed at different mist loading fractions, droplet diameters and blowing ratios. Various numbers of depositions were configured in the domain at different locations. An increase in the number of depositions at the plate surface raised the turbulence mixing of the fluids. It eventually weakened the film cooling performance. Moreover, the formation of depositions towards upstream after the coolant’s exit hole led to a decreasing film cooling effectiveness. It was also observed that the cooling performance was maximum at the highest blowing ratio, highest loading fraction, lowest droplet diameter and lowest injection angle.

Simulation of Deposition Detection inside Wellbore by Photon Backscatter Radiography

In the process of extracting oil and gas from hydrocarbon reservoirs, the formation of depositions inside pipes, fittings, and storage tanks, not only accelerates corrosion but also reduces a significant volume of operating capacities. The most critical step in solving the problem of deposition formation is their early and timely detection. In industries, internal surfaces of the pipeline are usually inspected by nondestructive testing (NDT) methods. The detection of depositions should operationally be difficult if there were special conditions for accessing the back of pipelines. Therefore, a suitable method is encouraged to detect deposition in the pipes and tubes when one side or a small part of them is accessible. In this paper, the Monte Carlo simulation tool was applied to use backscatter radiography (as an NDT inspection technique) for in-situ detection of depositions inside the metallic pipelines. In fact, the simulation process shows the correctness and efficiency of the backscatter radiography technique. It would determine some significant factors such as photon energy, angle of irradiation, or location of detectors which affect the design before experiment. The results showed that backscatter radiography as a viable technique could properly detect the location of depositions inside the pipes.

Predicting and Improving Hydraulic Performance of Pumping Suction Intakes By Computational Fluid Dynamics (CFD)

The disturbance in velocity distribution generates hydraulic instability of pumping units, which leads to failure, damage and other operation and maintenance difficulties. The objective of this research is to predict and enhance the hydraulic problems in the sump intake of FARASKOUR drainage pumping station on faraskour drain Damietta governorate. the first and fifth units of the operating, water were not analyzed, study of the hydraulic problems of the suction basin of the new pump station due t o the sharp rotation in the suction guide from the sharp rotation to the quay station and the continuous discontinuation of the first and fifth units due to the lack of regular water entering the unit. And recommends the suitable modifications to eliminate the operations and maintenance costs. A numerical simulation was done to investigate the hydraulic stability of the station. There are Four cases were done. The first case, when all units “five units” operate at the same time, the second case when three units operate “1, 2 and 3”, the third case when other three units “3, 4 and 5” operate, and the last case when three units “1, 3 and 5” operate. The ANSYS R18.1 flow simulation software, Computational Fluid Dynamics (CFD) is used to simulate the flow conditions at different working pumping units and different water levels to predict the hydraulic problem at the suction side. The results indicate that the problem of flow is due to the sharp bending of the suction channel at the entrance of the units to the station, leading to two negative phenomena, the first one not to distribute well to the incoming lines of the units, and the second is the appearance of places of relatively low speeds. The internal bending of the stream just before the entry of units directly to this area affects negatively the work of units (4, 5) and the problem becomes more specific with the formation of depositions. In general, the results indicate that with five pumping units’ scenarios in operation appear Dead zones in the inner curvature of the intake. From simulation results, the geometry of the intake is proper for running four parallel flow pumps with the designed flow rate and reduces the distance from both sides of the canal (make Protection basin).

Determination of eccentric deposition thickness on offshore horizontal pipes by gamma-ray densitometry and artificial intelligence technique

The extraction of oil is accompanied by water and sediments that, mixed with the oil, cause the formation of scale depositions in the pipelines walls promoting the reduction of the inner diameter of the pipes, making it difficult for the fluids to pass through interest. In this sense, there is a need to control the formation of these depositions to evaluate preventive and corrective measures regarding the waste management of these materials, as well as the optimization of oil extraction and transport processes. Noninvasive techniques such as gamma transmission and scattering can support the determination of the thickness of these deposits in pipes. This paper presents a novel methodology for prediction of scale with eccentric deposition in pipes used in the offshore oil industry and its approach is based on the principles of gamma densitometry and deep artificial neural networks (DNNs). To determine deposition thicknesses, a detection system has been developed that utilizes a 1 mm narrow beam geometry of collimation aperture comprising a source of 137Cs and three properly positioned 2″×2″ NaI(Tl) detectors around the system, pipe-scale-fluid. Crude oil was considered in the study, as well as eccentric deposits formed by barium sulfate, BaSO4. The theoretical models adopted a static flow regime and were developed using the MCNPX mathematical code and, secondly, used for the training and testing of the developed DNN model, a 7-layers deep rectifier neural network (DRNN). In addition, the hyperparameters of the DRNN were defined using a Baysian optimization method and its performance was validated via 10 experiments based on the K-Fold cross-validation technique. Following the proposed methodology, the DRNN was able to achieve, for the test sets (untrained samples), an average mean absolute error of 0.01734, mean absolute relative error of 0.29803% and R2 Score of 0.9998813 for the scale thickness prediction and an average accuracy of 100% for the scale position prediction. Therefore, the results show that the 7-layers DRNN presents good generalization capacity and is able to predict scale thickness with great precision, regardless of its position inside the tube.

Production and purification of hydrogen by biogas combined reforming and steam-iron process

Cobalt ferrite and hematite with minor additives have been tested for production and purification of high purity hydrogen from a synthetic biogas by steam-iron process (SIP) in a fixed bed reactor. A catalyst based in nickel aluminate has been included in the bed of solids to enhance the rate of the reaction of methane dry reforming (MDR). The reductants resulting from MDR are responsible for reducing the oxides based on iron that will, in the following stage, be oxidized by steam to release hydrogen with less than 50 ppm of CO. Coke minimization along reduction stages forces to operate such reactors above 700 °C for reductions, and as low as 500 °C for oxidations to avoid coke gasification. To avoid problems such as reactor clogging by coke in reductions and/or contamination of hydrogen by gasification of coke along oxidations, steam in small proportions has been included in the feed with the aim of minimizing or even avoiding formation of carbonaceous depositions along the reduction stage of SIP. Since steam is an oxidant, it exerts an inhibiting effect upon reduction of the oxide, that slows down the efficiency of the process. It has been proved that co-feeding low proportions of steam with an equimolar mixture of CH4 and CO2 (simulating a poor heating value desulphurized biogas) is able to avoid coke deposition, allowing the operation of both, reductions and oxidations, in isothermal regime (700 °C). Empirical results have been contrasted with data found in literature for similar processes based in MDR and combined (or mixed) reforming process (CMR), concluding that the combination of MDR + SIP proposed in this work, taking apart economic aspects and complex engineering, shows similar yields towards hydrogen, but with the advantage of not requiring a subsequent purification process.

Easy and Fast Preparation of Large and Giant Vesicles from Highly Confined Thin Lipid Films Deposited at the Air–Water Interface

Lipid vesicles are supramolecular structures of great interest for industrial and research applications. They can be used simply to compartmentalize solutions and pack active molecules in femtoliter-scale volumes or as highly sophisticated drug delivery vehicles and dynamic cell-size bioreactors. For these reasons, many methods for the production of vesicles have been developed, and some of them present several drawbacks, such as long working times and the requirement of specific equipment to perform the technique. In this work, we present a method to produce vesicles from highly confined lipid films at the air–water interface. The procedure involves two simple steps: the formation of the thin lipid film at the air–water interface and then brief sonication (10 s). These films are obtained by depositing different aliquots of lipid organic solutions at the air–liquid interface of round-bottom Eppendorfs tubes. The morphology of the highly confined lipid thin films was studied by optical microscopy noting the formation of non-uniform depositions at the air–liquid interface, with the presence of thicker portions close to the container sidewall. Post-sonication, the presence of vesicles composed of 2-oleoyl-1-palmitoyl-sn-glycero-3-phosphocholine (POPC) or 1,2-dilauroyl-sn-glycero-3-phosphocholine (DLPC) was confirmed using the complementary techniques of fluorescence microscopy and flow cytometry. The size distribution investigations carried out by flow cytometry revealed the optimal concentrations to favor the formation of giant vesicles (GVs). Furthermore, we investigated aqueous phase encapsulation by adding calcein or green fluorescent protein (GFP) to the aqueous phase then characterized by fluorescence microscopy and flow cytometry. We demonstrate a fast and easy method for producing vesicles including GVs on demand.

Caledonian formation of gold-bearing sulfide depositions in Early Proterozoic gabbroids in the northern Ladoga region

We have studied Pb isotopic systems of K-feldspar, pyrite, and pyrrhotine from gabbroids and ore of the Velimyaki Early Proterozoic massif in the northern Ladoga region in the southeastern part of the Fennoscandian Shield. The isochronous Pb–Pb age of sulfides has been determined as ∼450 Ma, which corresponds to intersection of the regression line with the lead accumulation curve with μ = 10.4–10.8; the model Pb age of sulfides is close to isochronous under the condition that the composition of lead evolved from a geochemical reservoir with an age of 1.9 Ga. The isotopic parameters of the lead in sulfides and K-feldspar indicate their formation in upper crust conditions (μ = 238U/204Pb > 10). From the obtained data, it follows that the isotopic composition of lead in K-feldspar corresponds to a Proterozoic age (1890 Ma) of magmatic crystallization of the rocks in the massif, and strongly radiogenic lead sulfides testify, with the greatest probability, to the later (Caledonian) formation of sulfide ores.

Evaluation of scale formation in waterwall heated surfaces

This paper presents the possibility of forecasting assessments of the speed and the time of formation of depositions in the evaporator-tube elements of double-drum boilers. The values of thermal flow in the wall region of tank screens of boiler furnace are obtained, besides the velocity values of scaling metal corrosion products are obtained. Conclusions about the ability of forecasting unnominal situations and emergency risks dependent with damage to the screen surface heating pipes are made.

Structural Biology of Calcitonin: From Aqueous Therapeutic Properties to Amyloid Aggregation

AbstractUnder appropriate conditions, peptides and proteins can assemble from their native state into prefibrillar oligomers and then mature into fibrillar aggregates. This transition forms the molecular basis of several pathologies, often related to the deposition of these amyloid fibrils. Several hormone peptides involved in fundamental biological processes have the tendency to self‐assemble into amyloid fibrils, resulting in a loss of their native functions, and more importantly, entailing devastating consequences, such as the formation of amyloid depositions. Calcitonin is a 32 amino‐acid hormone peptide that can be considered a molecular paradigm for the central events associated with hormone misfolding. Calcitonin in its native form is involved in various physiological functions, including mediating calcium homeostasis and maintaining bone structure. It is the latter function that has motivated the use of calcitonin as an aqueous therapeutic agent for the treatment of bone‐related pathologies such as osteoporosis and Paget's disease. Despite some success as a therapeutic, calcitonin's ability to control these diseases is limited by its aggregation along the canonical amyloid aggregation pathway, compromising its long‐term stability as a therapeutic agent. A better understanding of the misfolding process would not only provide the structural basis to improve calcitonin's long‐term stability and activity as a therapeutic, but also provide valuable insights into pathological aggregation of other amyloids. In this work, we review the physiological roles of calcitonin, its structure, and aggregation process, and consider the effects of calcitonin's structure on its role as a therapeutic.

Long-term exposition to a high fat diet favors the appearance of β-amyloid depositions in the brain of C57BL/6J mice. A potential model of sporadic Alzheimer’s disease

AimsThe sporadic and late-onset form of Alzheimer’s disease (AD) constitutes the most common form of dementia. This non-familiar form could be a consequence of metabolic syndrome, characterized by obesity and the development of a brain-specific insulin resistance known as type III diabetes. This work demonstrates the development of a significant AD-like neuropathology due to these metabolic alterations. MethodsC57BL/6J mice strain were divided into two groups, one fed with a diet rich in palmitic acid (high-fat diet, HFD) since their weaning until 16 months of age, and another group used as a control with a regular diet. The analyses were carried out in the dentate gyrus area of the hippocampus using a Thioflavin-S stain and immunofluorescence assays. ResultsThe most significant finding of the present research was that HFD induced the deposition of the βA peptide. Moreover, the diet also caused alterations in different cell processes, such as increased inflammatory reactions that lead to a decrease in the neuronal precursor cells. In addition, the results show that there were also dysregulations in normal autophagy and apoptosis, mechanisms related to βA formation. ConclusionsThe present findings confirm that HFD favors the formation of βA depositions in the brain, a key feature of AD, supporting the metabolic hypothesis of sporadic AD.

Preparation and bioactivity of apatite coating on Ti6Al4V alloy by microwave assisted aqueous chemical method

To improve the bioactivity of titanium and its alloys, dense and uniform apatite coatings were prepared on Ti6Al4V titanium substrates using microwave assisted aqueous chemical method. The influence of the pretreatment to the titanium substrates and the Ca/P molar ratio of the microwave solution on the coating deposition and morphology, as well as the bioactivity of the coated samples were studied. Results showed that during the microwave process, alkali treatment followed by heat treatment to the titanium substrates would promote the rapid deposition of hydroxyapatite to form coating. And the morphologies of the apatite coatings could be adjusted by the Ca/P molar ratio of the microwave solution. After immersion test in simulated body fluid (SBF), the coated titanium alloy exhibits a good bioactivity by inducing the formation of apatite depositions.

A comparative study on the microstructure and surface property evaluation of coatings produced from nanostructured and conventional WC–Co powders HVOF-sprayed on Al7075

Conventional and nanostructured WC-12wt.% Co powders were HVOF sprayed on Al7075-T6. The nanocoatings presented slightly less microporosity, higher microhardness, higher fracture toughness but higher decarburization, than the conventional ones. The nanocoatings exhibited greater resistance to general corrosion and localized corrosion in 3.5% NaCl than their conventional counterparts. Other than an occasional removal of WC nanoparticles, corrosion modes appeared similar for both types of coatings, characterized by selective dissolution of Co, formation of protective surface films and crevice corrosion along interlayer boundaries. Both types of coatings exhibited high dry sliding wear resistance. Nevertheless, the wear performance of the nanocoatings was even superior than that of their conventional counterparts. Main wear modes included plastic deformation of binder, oxidative wear leading to the formation of lubricating oxides and adhesive wear leading to the formation of alumina-rich surface depositions (from the Al2O3 counter balls). Coating of Al7075 with nano WC–12Co was proved effective in terms of microstructural features, corrosion and wear behaviour.

Use of Cellulose and Oxidized Cellulose Nanocrystals from Olive Stones in Chitosan Bionanocomposites

Cellulose nanocrystals (CNC) and 2,2,6,6‐tetramethyl‐1‐piperidinyloxyl‐ (TEMPO‐) oxidized cellulose nanocrystals (CNC‐TEMPO) were prepared from olive stones. The prepared nanocrystals were characterized using transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and carboxylic groups content determination. The prepared nanocrystals were used as reinforcing elements in chitosan nanocomposites, which were characterized using X‐ray diffraction (XRD) and tensile strength properties. In addition, the bioactivity of the prepared chitosan nanocomposites was studied in vitro in simulated body fluid (SBF) using scanning electron microscopy (SEM) and electron diffraction X‐ray spectroscopy (EDX). The results showed positive effect of the nanocrystals on tensile strength properties of chitosan and noticeable reduction in its rate of dissolution in SBF due to presence of cellulose nanocrystals. Chitosan nanocomposites containing CNC‐TEMPO showed higher tensile strength properties and higher rate of dissolution in SBF than those containing cellulose nanocrystals. Nanocomposites containing CNC or CNC‐TEMPO could not form significant amounts of hydroxyapatite (HAp) upon immersion in SBF for up to 4 weeks. Upon addition of nanohydroxyapatite to chitosan/cellulose nanocrystals films, formation of new hydroxyapatite depositions was observed. Presence of cellulose nanocrystals in chitosan/HAp resulted in formation and deposition of higher amounts of new HAp than in case of using chitosan/HAp without cellulose nanocrystals.

Экспериментальная установка для изучения кинетики формирования отложений на стенках теплообменных аппаратов

Экспериментальная установка для изучения кинетики формирования отложений на стенках теплообменных аппаратов

Antiurolithiatic Activity of Extract and Oleanolic Acid Isolated from the Roots of Lantana camara on Zinc Disc Implantation Induced Urolithiasis

The present study was done to evaluate the antiurolithiatic activity of ethanolic extract of roots (ELC 200 mg/kg) and oleanolic acid (OA 60 mg/kg, O.A. 80 mg/kg, O.A. 100 mg/kg) isolated from roots of Lantana camara in albino wistar male rats using zinc disc implantation induced urolithiatic model. The group in which only zinc disc was implanted without any treatment showed increase in calcium output (23 ± 2.7 mg/dL). Cystone receiving animals showed significant protection from such change (P < 0.01). Treatment with OA and ELC significantly reduced the calcium output at a dose of OA 60 mg/kg (P < 0.01), OA 80 mg/kg (P < 0.01), ELC 200 mg/kg (P < 0.01), and OA 100 mg/kg (P < 0.001), as compared with zinc disc implanted group. The average weight of zinc discs along with the deposited crystals in the only disc implanted group was found to be 111 ± 8.6 mg. Group that received Cystone 500 mg/kg showed significant reduction in the depositions (P < 0.001). Similarly, the rats which received OA and ELC showed reduced formation of depositions around the zinc disc (P < 0.001). The X-ray images of rats also showed significant effect of OA and ELC on urolitiasis. Thus, OA and ELC showed promising antiurolithiatic activity in dose dependant manner.

Synthetic natural gas from wood: Reactions of ethylene in fluidised bed methanation

The synthesis step in the production of synthetic natural gas from wood, i.e. the methanation, was investigated by systematic experiments with commercial nickel catalyst in a micro-fluidised bed reactor. Ethylene in the feed is always converted completely; dominantly serial reactions of ethylene to ethane and further to methane under isothermal fluidised bed methanation conditions could be shown. Lower temperatures favour the production of the intermediate ethane while high temperatures cause the formation of carbon depositions and carbon whiskers. Applying optimal operation conditions, the hydrogenation of the unsaturated olefin not only avoids the deposition of carbon or coke, but also leads to an increase of the higher heating value (HHV) of the produced (raw) SNG.

Study of the Morphology of Wax Crystals in the Presence of Ethylene-co-vinyl Acetate Copolymer

Formation of wax depositions in production tubing and pipelines is a common problem in petroleum industry. It is in cases where fluid temperature is less than the wax appearance temperature, which is the result of reduction in wall temperature of pipeline as the environment temperature decreases. In such conditions the wax compounds precipitate out of solutions and form crystals with complicated structures. The overcoming such problems are costly and time consuming. Different methods such as using inhibitors are used to manage this problem. Inhibitors can be used to prevent wax deposition. The authors studied the morphology of wax crystals and its changes with addition of ethylene vinyl acetate copolymer using scanning electron microscopy. The results show that wax depositions in the absence of polymer are plate-like crystals. As the time increases the thickness of deposit increases and the change from plate-like crystals to spherulites (that is the sidelong growth of crystals around a nucleus) or semispherulites were observed. In addition, a small amount of ethylene vinyl acetate changes the morphology of wax crystals to mal crystals (the small crystals that are not grown). In fact when ethylene/vinyl acetate is used as an inhibitor, it can coalesce with wax crystals and interfere with the growth of crystals. So the ability of crystals to interconnect and form networks decreases. Therefore more crystals with smaller size can be produced. As a final result the removing of wax crystals will be much easier.

Density Functional Theory Studies on the Formation of CaCO3 Depositions on Cristobalite, Diamond, and Titanium Carbide Surfaces

Fouling caused by inversely soluble salts, like CaCO3, is a general problem on heat transfer surfaces. Carbonate depositions are typically cleanable with acids, but costs of energy losses, operation, and maintenance are significant. In this study, formation of CaCO3 depositions was investigated on cristobalite, diamond, and titanium carbide surfaces. The aim of the study was to clarify the detailed mechanisms of crystallization fouling during the initiation on crystalline phases existing in materials used as coatings (SiOx, TiCN, diamond-like carbon [DLC]), and to compare the results to the fouling mechanism of stainless steel (Cr2O3). In experimental studies of fouling, detailed mechanisms and description of sterical and electrostatic factors of surfaces are often very much simplified. In this work, molecular modeling was used to describe surface structures and to investigate the effect of process fluid (water) on the structures. The adsorption of water can be molecular or dissociative. During the dissociative adsorption, hydroxylated surface structures are formed. The existence of hydroxyl groups on the surfaces has an effect on the fouling mechanism. First, the dissociation probability of water on different surfaces was determined according to the adsorption mechanism and energies, and then the attachment of CaCO3 onto optimized and hydroxylated surfaces was investigated. As a result, the formation mechanism with detailed intermediate steps of CaCO3 deposition was obtained. The fouling takes place via hydrogen carbonate intermediates, but the final deposition structure was found to vary between surfaces.