Buildup Of Deposits Research Articles

Resonance Testing Data Evaluation Approaches for Scaling Onset Detection in Pipelines

Most industries dealing with pipelines face problems resulting from the buildup of deposits therein, such as reduced efficiency, downtime and increased maintenance costs. Although solutions to this issue have been sought for decades, no widely employed technique for monitoring growth of inorganic deposits (or ‘scaling’) in pipelines exists. In this research, a means of detecting the onset of scaling growth, by processing resonance testing data, was sought. For the resonance testing measurements the pipeline segment of interest is equipped with acceleration sensors which record signals generated by impacting the pipeline with a steel tip. The signals are Fourier transformed and analysed in the frequency domain, where a clear shift in frequency peak positions can be observed as the scaling thickness changes. How best to extract quantitative information from the generated frequency data is an open question. In this research, two data analysis approaches for scaling thickness prediction are compared: a supervised (binary classification) machine learning approach as well as a comparison-based change detection approach using cross-correlation. The supervised machine learning approach yields generalizable results for different acceleration sensors and impactor diameters whilst the change detection approach is sensitive from a scaling thickness of 0.5 mm. Whilst this research is specific to the pipe–scaling geometry—and type used in the experiments conducted, resonance testing can be applied to any pipe–scaling combination. The robustness of the data processing approaches presented in this work, when applied to other pipe–scaling materials and geometries, is the next point of research.

THE EFFECT OF THERMAL CYCLING ON DEPOSITION IN AN IMPINGEMENT/EFFUSION COOLING GEOMETRY

Abstract Experiments were conducted in a high-pressure deposition facility to study the effect of engine cycling on the successive buildup of deposits as aircraft shut down and power up. The test facility simulates the pressure and temperature environment of a combustor liner cooling circuit. The coolant flow temperature reaches 894K (1150 °F) and discharges into a 17atm (250 psi) cavity pressure at a nominal pressure ratio of 1.027. AFRL05 test dust with a 0-10micron size distribution is added to the coolant . The cooling circuit consists of a double-walled impingement/effusion cooling plate with nominal hole sizes on the order of 0.5mm. To simulate cycling, the facility is brought up to the desired operating conditions where the first batch of dust is delivered (2-8g). The facility is then ramped down to ambient conditions. Following a “dwell” period of approximately 24 hours, another batch of dust is delivered once the facility is brought back up to the desired operating condition. Test data were acquired for one, two, and four cycles with different dust mass delivered. Values such as discharge coefficient, pressure ratio, Reynolds Number, and temperature are used to evaluate the effects of dust deposition on the impingement/effusion plate setup. Dust capture efficiency is shown to be insensitive to cycling whereas flow blockage is negatively impacted by increased number of cycles for the same total mass delivered. The sloughing of deposit structures during cooling circuit cool down is postulated to be responsible for the observed behavior.

CFD simulation of arterial hypotension in a left anterior coronary artery section with potential clinical relevance

ABSTRACT Atherosclerosis is a complex cardiovascular condition characterised by the buildup of fatty deposits, known as plaques, on the inner walls of arteries. Stenosis occurs when the narrowing of an artery becomes particularly pronounced due to the accumulation of plaque. This narrowed lumen leads to significant pressure drops during blood flow, which may lead to decreased blood flow to the target tissues. The current study focuses on conducting computational fluid dynamic (CFD) simulations of blood flow within a linear segment of the LAD (Left anterior descending) coronary artery, subject to differing degrees of atherosclerotic stenosis. The simulations are performed using COMSOL Multiphysics 5.6®. The study has computed pressure drops by considering the laminar flow of blood as a two-phase non-Newtonian fluid. The rheological characteristics have been modelled using the Carreau Yasuda model. It considers varying stenosis severities ranging from 10% to 90%, coupled with blood velocities spanning from 0.07 m/s to 0.2 m/s. Additionally, the findings have been compared to results generated using the Power Law model and Casson-Papanastasiou model for blood rheology. The pressure drop within the stenosed section has been correlated with stenosis percentages through power law models.

Deposit sintering in modern Kraft recovery boilers − The role of NaOH?

Modern Kraft recovery boilers have become larger compared to earlier designs and burn higher black liquor dry solids (DS), leading to a more intense burning process and, therefore, increased sodium hydroxide (NaOH) concentration in the upper furnace. Indications of rapid deposit build-up and plugging issues in these boilers, specifically downstream of the superheaters, have been observed at lower temperatures than typically expected, which could be a consequence of the increased NaOH. Thermodynamic calculations were performed to explore the formation of NaOH(g) in boilers with high carbonate content in the fly ash particles and the effect of the presence of NaOH on the melting properties of the deposits. The results indicated that at low temperatures (<400 °C), almost no NaOH(g) is expected to be present in the flue gases. However, we propose that rapid cooling of flue gases across superheaters kinetically freezes the carbonation of NaOH(g), resulting in higher NaOH(g) concentrations than predicted by equilibrium calculations alone. At low temperatures, the remaining NaOH(g) vapors condense on the fly ash and form a melt, potentially leading to the sintering of deposits and plugging issues. To confirm this theory, sintering tests were carried out at 300–350 °C by doping electrostatic precipitator (ESP) ash from a recovery boiler with NaOH powder. It was observed that the doped pellets sintered and were much harder than the reference ones across various experimental conditions. The single particle reactor (SPR) test results showed that the pellets started to sinter immediately upon heating up to 350 °C, suggesting that NaOH melt-induced sintering is a rapid mechanism. The findings of this study may also have implications for boilers with a high sodium (Na) content.

Modelling the Influence of the Tube Support Plate on the Eddy Current Testing of the Steam Generator: Sensitivity Study &amp; Validation

Eddy current testing (ECT) of Steam Generator (SG) tubes is part of the maintenance program of Nuclear Power Plants. Tube Support Plates (TSP) are usually only considered as extraneous signals for tube inspection. However, for long-term operation of SGs, there is a safety concern related to the build-up of deposits in the TSPs flow holes. The clogging-up of the TSPs flow holes affect the safe thermal-hydraulic operation of SGs. The deposits come from the feedwater train and are mostly iron oxides (magnetite) with a weak electrical conductivity and magnetite permeability.The ability of ECT probes to detect and characterize TSPs deposits is therefore of great interest. The most common and industrial ECT technique, the bobbin coil, averages the surrounding electromagnetic field over 360°, whereas the geometry of tri-foiled and quadri-foiled TSPs, and thus of clogging, is rather complex and non- axisymmetric, hence motivating the evaluation of the performance of conventional ECT rotating probes used for SGs tubes inspection. Although simulation is a powerful tool to support such a study, it requires dedicated models to be made available to NDT experts, and CEA develops ECT physical models in CIVA for this purpose. In addition to standard fast CIVA modules based on 3D semi-analytical or 2D numerical calculations restricted to canonical or axisymmetric parts, respectively, CEA develops a module dedicated to the simulation of SG tube inspection based on a 3D numerical simulation. This module allows tube deformation such as ovalization, bending or tube expansion. It also allows the addition of external objects such as anti-vibration bars, different geometries of tube support plates and now their clogging by deposits. This model is used to study various influent parameters and to perform benchmarks in the framework of a scientific collaboration between the CEA and the IRSN. Here, the specificity of the TSPs and their clogging justifies qualifying the simulation model before evaluating the influence of material and geometry properties of the deposit as well as the performance of the inspection techniques. We present the main features of the simulation module in CIVA, its experimental validation, and the main trends in the distortion of the simulated signal as a function of variation in the clogging description.

Comparative Assessment of Head Deposition, Exhaust Gas Temperature and Sound Emission in CI Engine using Blend Fuel

Energy has a significant role in the socio-economic growth for any country. The energy originates from fossil fuels, which are non-renewable and enact an undesirable impact on the environment. Waste cooking oil can be utilized in diesel engine directly. Preheating and trans-esterification process are expensive to convert waste cooking oil into biodiesel. This research aims to replace diesel with waste cooking oil as binary blend and compared with diesel fuel. Engine testing at the constant speed of 1300 rpm at constant load. This study revealed that, addition of waste cooking oil reduced exhaust gas temperature as compared to base line fuel. In case of noise emission, sound level for emulsion fuel DF95WCO5 was reduced compared to DF. In this study, a single-cylinder CI engine was run for 200 hours on two fuel samples: DF (diesel fuel) as the baseline fuel and DF95WCO5 (5% waste cooking oil and 95% DF). During the endurance test, the effects of DF95WCO5 on engine head deposits were studied. According to the investigation's findings, visual inspection of both fuel samples revealed some deposit buildup on injectors. SEM (scanning electron microscopy) and EDX (energy dispersive X-ray spectroscopy) analysis revealed that the engine running with DF95WCO5 formed more carbon deposits on and around the head. It can be concluded that binary emulsion can be used in compression ignition engine without any engine alterations. Consequently, WCO can be proficiently used to reduce detrimental effects and reduce fossil fuel dependency.

Abstract 3048: The Role Of 17:0(2r-oh) Ceramide In Lps Activated Macrophages

Macrophages play a crucial role in the initiation and progression of atherosclerosis, contributing to the buildup of fatty deposits which results in the plaque formation in the walls of arteries. Macrophages modulate the mediators of inflammation and immune response in atherosclerosis. Bacterial lipopolysaccharide (LPS) exerts significant effects on these macrophages including secretion of pro-inflammatory cytokines. The current study is designed to examine the role of sphingosine intermediate N-(2'-(R)-hydroxyheptadecanoyl)-D-erythro-sphingosine (17:0(2R-OH) in the macrophage’s inflammation potential. Couple of studies have indicated a protective role for sphingosine however 17:0(2R-OH) didn’t receive adequate attention. Study design: Mouse J774 macrophages were cultured in Dulbecco’s Modified Eagle’s medium with 4.5g/L glucose and sodium pyruvate without L-glutamine containing 10% fetal bovine serum and 1% penicillin/streptomycin in a humidified atmosphere with 5% CO 2 at 37 °C. The cells were treated in 6-well plates at a density of 5.5х10 6 cells/well. Sphingosine was dissolved in DMSO prior to the treatment. The cells were treated with the 17:0(2R-OH) with 3 different concentrations (5, 25, 50 μg) in duplicates with or without LPS except for the controls. The cells and media were collected at 3 time points (12,24,36) hours. Cells were harvested in Trizol reagent, RNA was then extracted from cells and genes expression were determined in RTPCR using SYBR Green. Results and Conclusion: Our initial microscopic observations suggest that 17:0(2R-OH) potentially modulates inflammation in macrophages, this appears to be dose-dependent. 17:0(2R-OH) has been identified in marine and freshwater fish, marine oils, seaweed, sea urchins, sea cucumbers and may have dietary benefits.

Methods and metrics to assess the accuracy of heat flux data from a spark ignition IC engine

The measurement of in-cylinder heat transfer can be a valuable diagnostic tool for quantifying and improving IC engine performance. Increased heat transfer out of the combustion chamber negatively impacts overall efficiency, while heat transfer from the metal to the charge can increase knock propensity. The heat flux at various locations in an engine cylinder can be measured using heat flux probes consisting of two thermocouples – a surface thermocouple exposed to the changing in-cylinder temperatures, and a far field thermocouple which has a constant temperature at steady state operating conditions. The buildup of carbon deposits on the surface thermocouple can affect the heat flux measurements and lead to errors in the data. Heat flux measurements were performed on a proprietary single-cylinder research engine with instrumented heat flux probes in the cylinder head and cylinder liner. The engine was run rich with a high PMI fuel to expedite the buildup of carbon deposits. A metric was developed based on the output of the surface thermocouple to determine the cleanliness of the heat flux probes non-intrusively. Heat flux calculations were done using the FFT method and validated using the Cook-Felderman method. An uncertainty analysis was conducted on the heat flux data to verify that the negative heat flux observed was not due to errors in the distance between the two thermocouples or the measurement of temperature. Finally, to bolster confidence in the results, heat flux measurements were made for motoring conditions with varying coolant and intake air temperatures to gauge whether the trends in the output were in the expected direction.

Laser and microwave instrumentation for ITER and future reactors

ITER diagnostics include an extensive set oflaser and microwave diagnostics to give access to a wealth of information on thecore and edge plasma and to support high performance operation of ITER. Forexample, Core and Edge Thomson scattering systems build detailed density andtemperature profiles on time scales much faster than τ E to follow transientevents; ECE and reflectometry add time resolution to follow MHDevents. Implementing these diagnostics is challenging, needing a panoply oftechnologies to keep them functioning reliably for thousands of hours despiteextreme events such as disruptions and wall conditioning cycles. Shielding,shutters and cleaning systems protect the forward elements of most opticalsystems from the build-up of deposits and damage. Still, plasma-facing mirrorsmust survive laser loads and endure erosion, deposition and in-situ RFcleaning. Calibration and monitoring systems ensure accurate and drift-freeoperation. These support systems are also not straightforward and requiredspecific R&D. Access also drives the design: to deal with the neutronand gamma sources yet allow maintenance of activated components, ITER useslarge, multi-purpose ports that couple otherwise distinct systems into modulesfor maintenance. Machine movement requires provisions to maintain alignment andcalibration, from these port plugs, shown in figure 1, to theaccessible areas 10–50 m away. A final complication comes from the difficulty ofemploying electronics near the plugs. Extensive qualification for radiationresistance is needed. This paper examines design adaptations that ITER adoptedfor its near-reactor environment, consider the lessons learnt from the ITERdesign activity specifically for laser and microwave systems and lays out somepossible evolution paths for the reactor diagnostician that must follow a moreindustrial approach.

Integrative care: acupuncture based neuromodulation therapy for diabetes and heart failure.

The relationship between heart failure and diabetes is intricate and bidirectional. Individuals with diabetes face an elevated risk of developing heart failure due to factors like insulin resistance, chronic inflammation, and metabolic irregularities. Elevated blood sugar levels can harm blood vessels and nerves, culminating in the buildup of fatty deposits in arteries, atherosclerosis, and hypertension, which significantly contribute to heart failure. Furthermore, diabetes can adversely impact the structure and function of the heart muscle, impairing its pumping capacity. Conversely, heart failure can also contribute to the onset of diabetes by disrupting the body's metabolic processes and amplifying insulin resistance. The complex interaction between these conditions mandates a comprehensive approach to managing individuals with both diabetes and heart failure, underscoring the importance of addressing both aspects for enhanced patient outcomes. Although existing pharmacological treatments are limited and frequently associated with undesirable side effects, acupuncture has established itself as a traditional practice with a legacy. It remains a supplementary option for treating cardiovascular diseases. Heart failure and diabetes are both heavily associated with chronic upregulation of the sympathetic nervous system, which has been identified as a pivotal factor in the progression of disease. Mechanistic interplays such as the attenuation of central nitric oxide signaling may interfere with the production or availability of nitric oxide in key areas of the central nervous system, including the brainstem and hypothalamus. This review will delve into the current understanding of acupuncture on the autonomic nervous system and offer insights into its potential role in the future treatment landscape for diabetes and heart failure.

The interplay between bacterial biofilms, encrustation, and wall shear stress in ureteral stents: a review across scales

Ureteral stents are hollow tubes that are inserted into the ureter to maintain the flow of urine from the kidney to the bladder. However, the use of these indwelling stents is associated with potential complications. Biofilm, an organized consortium of bacterial species embedded within a self-producing extracellular matrix, can attach to the outer and inner surfaces of ureteral stents. Furthermore, encrustation - defined as the buildup of mineral deposits on the stent surface - can occur independently or in parallel with biofilm formation. Both phenomena can cause stent obstruction, which can lead to obstructive pyelonephritis and make stent removal difficult. Understanding the influence of flow on the development of biofilm and encrustation and the impact of small mechanical environmental changes (e.g., wall shear stress distribution) is key to improve the long-term performance of stents. Identifying the optimal stent properties to prevent early bacterial attachment and/or crystal deposition and their growth, would represent a breakthrough in reducing biofilm-/encrustation-associated complications. This review identifies the most prevalent bacterial strains and crystal types associated with ureteral stents, and the process of their association with the stent surface, which often depends on patient comorbidities, stent material, and indwelling time. Furthermore, we focus on the often-overlooked role of fluid dynamics on biofilm and encrustation development in ureteral stents, across a range of physical scales (i.e., from micro- to macro-scale) with the aim of providing a knowledge base to inform the development of safer and more effective ureteral stents.

Femoro-popliteal Artery Bypass and Transmetatarsal Amputation Followed by Delayed Forefoot Flap

Critical limb ischemia (CLI) is a severe blockage in the arteries of the lower extremities, which markedly reduces blood-flow. It is a serious form of peripheral arterial disease, or PAD, but less common than claudication. PAD is caused by atherosclerosis, the hardening and narrowing of the arteries over time due to the buildup of fatty deposits called plaque. CLI is a chronic condition that results in severe pain in the feet or toes, even while resting. Complications of poor circulation can include sores and wounds that won't heal in the legs and feet. Left untreated, the complications of CLI will result in amputation of the affected limb. The authors present a patient with CLI, and a left forefoot gangrene treated with multi-stage operations (femoro-popliteal arterial bypass, transmetatarsal amputation and delayed forefoot free-flap) with good results.

Exploration of KCl deposition dynamics for the formation of coarse and fine layer deposits

In biomass and waste combustion, the release of KCl into the gas phase results in its deposition on heat exchanger surfaces, enhancing their stickiness and accelerating deposit buildup from incoming ash particles. Despite this, the mechanisms governing KCl deposition remain inadequately explored. KCl has been observed to form either a fine, powdery layer through thermophoresis of nucleated KCl particles or a crystal-like, coarse layer through heterogeneous condensation of KCl vapor. However, the quantitative assessment of coarse and fine layer formation has never been performed. In this study, an entrained flow reactor and mechanistic model were employed to analyze KCl deposition behavior, examining the effect of probe temperature and exposure time. Quantification of both the coarse and fine deposit layers was accomplished. Probe temperature was found to have no influence on the deposition in the range from 300 °C – 595 °C. For coarse layer formation, the critical factor was the development of a fine layer upon which the crystal-like structure of the coarse layer grows. Lower probe temperatures accelerate initial layer formation, initiating the coarse section sooner. Additionally, it slightly increases nucleation and condensation, however, nucleation is increased stronger resulting in a lower ratio of coarse to fine deposit. The quantification of the coarse mass, in conjunction with the simulation, provides a first estimation of the critical mass required to initiate heterogeneous condensation on a steel tube. In this study, a critical mass of 1.26e-3 g/cm2 was determined.

Elevated Amyloid‐β and Tau Levels in the Brain are Associated with a Reduced Abundance of Neuroprotective Gut Bacteria

AbstractBackgroundRecent research suggests that differences in the gut microbiome composition may contribute to the pathogenesis of neurological disorders, including Alzheimer’s disease (AD). Animal studies have shown that fecal microbiota transplantation reduces amyloid plaques in mouse AD models. However, whether the buildup of Aβ and tau deposits in the brain are associated with shifts in the human gut microbiota composition is understudied.MethodWe used stool specimens and neuropathological measures from 140 middle‐aged individuals (Table 1: mean age 56, 54% Female) from the Framingham Heart Study (FHS) to assess the link between the gut microbiome composition and Aβ Positron Emission Tomography (Aβ‐PET) in a global composite brain measure, and tau‐PET deposits in the rhinal cortex and the inferior temporal cortex. We quantified gut microbiome composition using 16S rRNA sequencing. We performed multivariable association and differential abundance analyses, adjusting for age, sex, body mass index, and other confounders.ResultMultivariable association results (Figure 1) indicated significant associations (adjusted p‐value &lt; 0.001) between both Aβ‐PET and tau‐PET levels with abundance of genera Butyricicoccus and Ruminococcus. Moreover, differential abundance analysis (Figure 2) showed that these bacteria have lower than expected abundance in individuals with elevated Aβ‐PET and tau‐PET measures (Aβ‐PET, Ruminococcus: OR = 0.89, [0.88, 0.91]; Butyricicoccus: OR = 0.77, [0.72, 0.81]); (tau‐PET in the rhinal cortex: Ruminococcus: OR = 0.82, [0.8, 0.83]; Butyricicoccus: OR = 0.91 [0.88, 0.94]); (tau‐PET in the inferotemporal cortex:, Ruminococcus: OR = 0.79 [0.78, 0.81]; Butyricicoccus: OR = 0.83 [0.81, 0.86]). Conversely, we observed an increased abundance of genera Cytophaga (tau‐PET in the rhinal cortex, OR = 1.78, [1.15, 2.75]) and Alistipes (tau‐PET in the rhinal cortex, OR = 1.19, [1.17, 1.22]) in individuals with high Aβ‐PET and tau‐PET levels. Finally, functional analysis showed that Butyricicoccus and Ruminococcus are butyrate‐producing bacteria harboring neuroprotective effects.ConclusionWe showed that elevated measures of Aβ‐PET and tau‐PET in the rhinal and the inferior temporal cortex are associated with a reduced abundance of butyrate‐producing Butyricicoccus and Ruminococcus in the gut of middle‐aged individuals from the FHS. As these bacteria harbor neuroprotective effects, further studies are needed to elucidate underlying mechanisms and assess their therapeutic potential.

Process intensification of microplasma nanoparticle synthesis enabled by gas flow design

The wide range of practical uses for nanometer-size metal particles has motivated many lab-scale aerosol synthesis processes. It is well known that the aggregation dynamics of aerosol particles impose a trade-off between particle size and concentration: methods that achieve sub-10 nm particles without aggregation are generally limited by low concentration and low flow rates of order 100 cm3/min. Thus, the intensification of aerosol nanoparticle synthesis and its development for industrial use remains a unique and important manufacturing challenge. We present a microplasma reactor system that has been developed to improve process intensification and reliability. The system utilizes an atmospheric pressure DC microplasma to synthesize iron-carbon particles from a ferrocene vapor precursor. The microplasma incorporates a novel focusing technique using a spatial gradient in gas composition to stabilize short-term fluctuations in performance, achieving an iron yield of up to 0.93. We identify the build-up of deposits between the plasma electrodes as the primary cause of reduced performance over time, and eliminate this build-up by indirectly supplying ferrocene to avoid dissociation in this region of the reactor. Further, we show that the design and conditions downstream of the microplasma have a similar influence on the final particle size distribution as those of the microplasma itself. By tuning the coupled process variables of both the microplasma and this downstream region, we synthesize aerosols with mean diameter from 2 to 7 nm and number concentration of 2 to 8×109 #/cm3 at the system outlet.

Recurrence after cytoreductive surgery and HIPEC for pseudomyxoma peritonei: A single-center retrospective cohort study.

Pseudomyxoma peritonei (PMP) is a rare disease characterized by progressive build-up of mucinous deposits inside the abdominal cavity. The aim of this study was to investigate the effect of disease recurrence on overall survival in patients with PMP after cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC). One-hundred thirty-two consecutive PMP patients treated with CRS + HIPEC at Helsinki University Hospital between 2008 and 2017 were included. The impact of clinicopathological and treatment-related characteristics on recurrence and overall survival was evaluated. The median follow-up time in the study was 5.04 (range = 0.05-11.60) years. In 121 (91.7%) patients, the disease was classified as low grade and 11 (8.3%) had high-grade disease. In the low-grade group, 26 (21.5%) patients developed a recurrence during follow-up compared to 6 (54.5%) patients in the high-grade group. In the low-grade group, cumulative survival was 98.2%, 91.4%, and 91.4% at 3, 6, and 8 years, respectively. In the high-grade group, cumulative survival was 90.0% and 78.8% at 3 and 6 years, respectively. In patients with recurrent disease, the cumulative survival was 100%, 84.6%, and 84.6% at 3, 6, and 8 years in the low-grade category and 80.0% and 60.0% at 3 and 6 years in the high-grade category, respectively. In the low-grade group, a statistically significant correlation with recurrence but not with overall survival was identified with peritoneal cancer index (PCI), carcinoembryonic antigen (CEA), and the number of affected regions. The recurrence of low-grade PMP does not significantly affect overall survival of patients. Disease extent may not be a prognostic indicator after curative CRS and HIPEC in low-grade PMP.

Advances in drug delivery to atherosclerosis: Investigating the efficiency of different nanomaterials employed for different type of drugs.

Atherosclerosis is the build-up of fatty deposits in the arteries, which is the main underlying cause of cardiovascular diseases and the leading cause of global morbidity and mortality. Current pharmaceutical treatment options are unable to effectively treat the plaque in the later stages of the disease. Instead, they are aimed at resolving the risk factors. Nanomaterials and nanoparticle-mediated therapies have become increasingly popular for the treatment of atherosclerosis due to their targeted and controlled release of therapeutics. In this review, we discuss different types of therapeutics used to treat this disease and focus on the different nanomaterial strategies employed for the delivery of these drugs, enabling the effective and efficient resolution of the atherosclerotic plaque. The ideal nanomaterial strategy for each drug type (e.g. statins, nucleic acids, small molecule drugs, peptides) will be comprehensively discussed.

Modelling the Influence of the Tube Support Plate on the Eddy Current Testing of the Steam Generator: Numerical Tools and Experimental Validation

Eddy current testing (ECT) of Steam Generator (SG) tubes is part of the maintenance program of Nuclear Power Plants. Tube Support Plates (TSP) are usually only considered as extraneous signals for tube inspection. However, for long-term operation of SGs, there is a safety concern related to the build-up of deposits in the TSPs flow holes. The clogging-up of the TSPs flow holes affect the safe thermal-hydraulic operation of SGs. The deposits come from the feedwater train and are mostly iron oxides (magnetite) with a weak electrical conductivity and magnetic permeability. The ability of ECT probes to detect and characterize TSPs deposits is therefore of great interest. The most common and industrial ECT technique, the bobbin coil, averages the surrounding electromagnetic field over 360°, whereas the geometry of tri-foiled and quadri-foiled TSPs, and thus of clogging, is rather complex and non-axisymmetric, hence motivating the evaluation of the performance of conventional ECT rotating probes used for SGs tubes inspection. Although simulation is a powerful tool to support such a study, it requires dedicated models to be made available to NDT experts, and CEA develops ECT physical models in CIVA for this purpose. In addition to standard fast CIVA modules based on 3D semi-analytical or 2D numerical calculations restricted to canonical or axisymmetric parts, respectively, CEA develops a module dedicated to the simulation of SG tube inspection based on a 3D numerical simulation. This module allows tube deformation such as ovalization, bending or tube expansion. It also allows the addition of external objects such as anti-vibration bars, different geometries of tube support plates and now their clogging by deposits. This model is used to study various influent parameters and to perform benchmarks in the framework of a scientific collaboration between the CEA and the IRSN, related for example to the inspection of the U-bend tubes or of a friction wear under the anti-vibration bars. Here, the specificity of the TSPs and their clogging justifies further investigations between CEA and IRSN to qualify the simulation model before evaluating the influence of material and geometry properties of the deposit as well as the performance of the inspection techniques. We present the main characteristics of the simulation module in CIVA.

Preliminary Results of Innovative Two-Stage Torrefaction Technology Applied for Thermochemical Treatment of Sunflower Husk

This article proposes an innovative two-stage technology for biomass torrefaction generating high-quality biochar, more specifically biocoal, as solid fuel, and offering a promising solution to the challenges posed by the combustion of biomass. In particular, the higher quality of biochar as solid fuel reduces the build-up of unmanageable deposits on fired surfaces, as these deposits inhibit heat transfer and reduce the efficiency of biomass boilers. The proposed two-stage technology involves torrefaction in a hearth-type reactor at temperatures up to 250 °C, followed by a subsequent stage of cooling achieved through washing with water. The two-stage torrefaction technology is integrated within a vertical hearth reactor vessel composed of three superimposed trays serving for biomass input, torrefaction, and water washing combined with biomass cooling, respectively. Upon contact with torrefied biomass, cooling water turned into water vapor; hence, eliminating the requirement for subsequent biomass separation and drying. The system was tested on sunflower husk, and results showed a reduction in the content of problematic elements such as alkali metal chlorides or sulfur compounds in biochar ash, suggesting lower corrosion rates of convective heating surfaces of the boiler under ash sediments. It is hypothesized that, while water exited hot biomass in the form of water vapor instead of liquid water, as is typically the case in water-washing processes, a share of undesirable elements may still have been removed from biomass through vaporization, without necessitating any additional process for ash removal. Hence, the index values calculated according to the chemical analysis of biomass ash suggested that sunflower husk biochar (biocoal) resulting from the proposed two-stage torrefaction process may display fuel characteristics similar to biomasses whose combustion ash may form reduced levels of deposits on boiler surfaces. Therefore, the proposed technology holds the potential to improve solid fuel characteristics of biomass, targeting enhanced efficiency and sustainability of biomass-fired power plants.

Coking of gas turbine lubrication oils at elevated temperatures

Over the last several decades, turbine efficiency has improved significantly, resulting in higher turbine operating temperatures that negatively affect the lubricating oil circulating through the system. Exposure to high temperatures results in oil degradation and the eventual formation of solid deposits in the oil which greatly limit the oil’s ability to reduce wear and cool the turbine components. An experimental apparatus was designed and built to allow for the studying and better understanding of this phenomenon. The apparatus consists of a flow loop with a heated test section through which the oil is pumped. The oil that comes into contact with the hot surfaces degrades and forms solid deposits. As time passes, the deposit buildup decreases the heat transfer that occurs at the test section. The bulk oil temperatures into and out of the test section are used as indicators of the deposit induction time and buildup rate, and the deposits may be analyzed at the end of the experiment. Air or an inert gas may be used to pressurize the system up to 69 bar, while test section surface temperatures may be as high as 650°C. Data from one of the initial tests performed with the apparatus using a gas turbine lube oil are included in this paper. The test resulted in the clear formation of solid deposits on the heated surfaces and in the data that show the decrease in the bulk oil temperature over time due to their formation. Assembly and testing of the apparatus have been completed, and it is now fully operational and ready for future studies on lubricating oil thermal degradation and oxidation.