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Lymphangiomas are benign lymphatic system abnormalities that can appear anywhere on the skin and mucous membranes. Lymphangiomas are caused by congenital or acquired lymphatic system disorders. In the congenital form, although the cause is unknown it is said that it is formed by the incorrect attachment of lymphatic channels to the main lymphatic drainage duct before the age of 5 years. lymphangiectasia as a subgroup of lymphangioma occurs seldom in the small bowel, especially in adults. If that happens, protein-losing enteropathy will be the most common presenting sign. In the present study, we introduce a case of a 40-year-old man without a history of any congenital or acquired diseases who was admitted to the emergency room due to long-lasting obscure overt gastrointestinal (GI) bleeding. Normal upper and lower GI endoscopies were suggestive of GI bleeding originating from the small intestine. Despite receiving iron supplements, he continued to have melena and remained anemic. Further evaluation of the small intestine by deep enteroscopy revealed multiple white spots histologically consistent with dilated lymphatics. Intestinal lymphangiectasia was eventually introduced to be the final diagnosis of the patient.

Cathodic protection as a complementary method is one of the most effective ways to prevent corrosion, along with coating and choosing the suitable material. There are different ways to protect the storage tank bottom. Due to the presence of the geo membrane layer and its effective and pivotal role, the use of mixed metal oxide (MMO) anodes is highly recommended. In the current study, the protection process of the above-ground storage tank bottom is simulated using MMO backfilled wire (Concentric Rings) and ribbon anodes (Mesh Grid System). In this regard, several parameters must be considered in reaching the protection criteria. The simulation results show that the effect of the spacing between the anodes, the limiting oxygen current density and the anodic current have the greatest role. Anode depth and soil resistance are also critical factors. Due to the importance of the number of conductor bars and feeding cables, two configurations have been presented for ribbon anodes. These configurations have a direct impact on grid resistance, rectifier size, and related costs. Finally, an economic comparison has been made regarding the use of sacrificial and MMO anodes in the form of ribbon next to wire anodes. The results show that, in the use of ribbon anodes, MMO anodes have better performance than magnesium and zinc sacrificial anodes, and the cost required for MMO linear anodes is far lower than the method of sacrificial ribbon anodes. In the present study, the linear anode system has an estimated cost of approximately 20% less than the ribbon sacrificial anodes made of magnesium and zinc.

Pyoderma gangrenosum (PG) is a relatively uncommon disorder associated with autoimmune and inflammatory conditions, including inflammatory bowel disease (IBD). PG’s prevalence ranges from 0.4 - 2.6% in patients with IBD. We describe a 34-year-old man with ulcerative colitis (UC) who was referred to our center with some small follicular and pustular lesions rapidly progressing into a painful necrotic ulcer in the right axilla. The ulcer was not responsive to broad spectrum antibiotics and topical cytotoxic agents like tacrolimus. Finally, a dramatic response was observed after initiating anti-tumor necrosis factor (anti-TNF) treatment with infliximab (10 mg/kg) within a week. A significant reduction in size and necrotic tissue was achieved one month after the index date of the prescription of infliximab. A 2-month follow-up of the patient revealed complete healing of the lesion.

Alzheimer's disease (AD) is the most common type of cognitive disorder in an elderly population associated with the accumulation of amyloid plaques and neurofibrillary tangles. Nerolidol is assumed to have neuroprotection effects. This study aimed to investigate the therapeutic effects of nerolidol on the Aβ-induced model of AD in rats. Hippocampal injection of Aβ was used to induce AD. Animals were randomly divided into control, sham (received PBS as Aβ solvent), AD, DNPZ (AD + donepezil, 4 weeks); NRD-50 (AD + nerolidol, 50 mg/kg, 4 weeks), NRD-100 (AD + nerolidol, 100 mg/kg, 4 weeks; Prot (rats which received 100 mg/kg nerolidol for two weeks before Aβ administration), and Solv (AD + sunflower oil as nerolidol solvent, 4 weeks) groups. All rats were subjected to a memory behavioral passive avoidance test by shuttle box. Thioflavin-S staining was performed to confirm Aβ plaque formation and measured using ImageJ analyzing program. BDNF and CREB-1 expressions were analyzed by immunohistochemistry assay. Aβ induced AD by Aβ plaques formation and increasing step-through latency time. It reduced the expression of BDNF and CREB-1 protein. Administration of nerolidol or donepezil improved these features by decreasing Aβ and increasing BDNF and CREB-1 expression and latency time. Nerolidol is likely to provide protection against AD. It may prevent dementia through the mediation of BDNF-CREB-1 expression and cholinergic nerve cells restoring. It seems that the administration of nerolidol before the onset of the disease will be more effective than after.

Extrusion-based 3D printing followed by debinding and sintering is a powerful approach that allows for the fabrication of porous scaffolds from materials (or material combinations) that are otherwise very challenging to process using other additive manufacturing techniques. Iron is one of the materials that have been recently shown to be amenable to processing using this approach. Indeed, a fully interconnected porous design has the potential of resolving the fundamental issue regarding bulk iron, namely a very low rate of biodegradation. However, no extensive evaluation of the biodegradation behavior and properties of porous iron scaffolds made by extrusion-based 3D printing has been reported. Therefore, the in vitro biodegradation behavior, electrochemical response, evolution of mechanical properties along with biodegradation, and responses of an osteoblastic cell line to the 3D printed iron scaffolds were studied. An ink formulation, as well as matching 3D printing, debinding and sintering conditions, was developed to create iron scaffolds with a porosity of 67%, a pore interconnectivity of 96%, and a strut density of 89% after sintering. X-ray diffracometry confirmed the presence of the α-iron phase in the scaffolds without any residuals from the rest of the ink. Owing to the presence of geometrically designed macropores and random micropores in the struts, the in vitro corrosion rate of the scaffolds was much improved as compared to the bulk counterpart, with 7% mass loss after 28 days. The mechanical properties of the scaffolds remained in the range of those of trabecular bone despite 28 days of in vitro biodegradation. The direct culture of MC3T3-E1 preosteoblasts on the scaffolds led to a substantial reduction in living cell count, caused by a high concentration of iron ions, as revealed by the indirect assays. On the other hand, the ability of the cells to spread and form filopodia indicated the cytocompatibility of the corrosion products. Taken together, this study shows the great potential of extrusion-based 3D printed porous iron to be further developed as a biodegradable bone substituting biomaterial.

Herein, we report a feasible method for forming barrel-like hybrid Cu(OH)2-ZnO structures on α-brass substrate via low-potential electro-oxidation in 1 M NaOH solution. The presented study was conducted to investigate the electrochemical behavior of CuZn in a passive range (−0.2 V–0.5 V) and its morphological changes that occur under these conditions. As found, morphology and phase composition of the grown layer strongly depend on the applied potential, and those material characteristics can be tuned by varying the operating conditions. To the best of our knowledge, the yielded morphology of barrel-like structure has not been previously observed for brass anodizing. Additionally, photoactivity under both UV and daylight irradiation-induced degradation of organic dye (methyl orange) using Cu(OH)2-ZnO composite was explored. Obtained results proved photocatalytic activity of the material that led to degradation of 43% and 36% of the compound in UV and visible light, respectively. The role of Cu(OH)2 in improving ZnO photoactivity was recognized and discussed. As implied by both the undertaken research and the literature on the subject, cupric hydroxide can act as a trap for photoexcited electrons, and thus contributes to stabilizing electron-hole recombination. This resulted in improved light-absorbing properties of the photoactive component, ZnO.

This study aimed to design and construct a quadruple solar/hydro/biomass/geothermal hybrid system, using a techno-economic analysis for water/biofuel production as energy carriers. First, in the case of the ground source heat pump-assisted microalgal culture pond, three influencing factors including light intensity, salinity, and air injection were investigated for maximum biomass production. Then, in the parabolic trough collector, the flow rate of operating fluid, the used hybrid nanoparticles, and their ratios were considered for obtaining the highest thermal efficiency. After, providing a better solar still distiller for the highest water production efficiency, the pressure, fluid’s flow rate, and the depth of solar still were investigated. Finally, the water/heart supply of producing biodiesel from the pond’s biomass in the trans-esterified conversion reactor was provided from the distiller/collector. The results indicated that using a 300-lx light intensity, a 3-g/L salinity, and a 0.4-L/min air injection in the pond, a 3-L/min nanofluid, including CuO/GO (4:1) and mass fraction of 0.4 in the operating fluid in the collector, a 2.5-cm water depth under a 0.4-bar pressure in the distiller, and a 1.8-wt%/wt catalyst concentration under a reaction temperature of 55 °C at 50 min in the reactor would yield the best water/biofuel production efficiency of 55%/80%.

Our work provides a thorough characterization of different biochars produced by a novel 50 kWth Indirectly Heated Bubbling Fluidized Bed Steam Reformer. This study investigates the effect of temperature and gasification agent on the physico-chemical properties of biochars. We combined macro, micro and nano characterization techniques to provide a clear picture of the biochar characteristics, surface functionality and its “inert” nature toward potential applications. Our results demonstrate that indirect gasification is capable of producing carbon-rich biochars (> 92%) with increased porosity (89–198 cm3.g−1), high heating value (28–31 MJ.kg−1 a.r.) and aromaticity compared to the parent biomass. All biochars have lower O/C (0.02–0.04) and H/C atomic ratios (0.09–0.19), similar to anthracite. For the range of tested gasification conditions, air/steam gasification at an equivalence ratio of 0.20 and steam-to-biomass ratio of 1.2 provides the highest biochar yield (7.3%), while maintaining syngas composition optimal. On the other hand, air gasification produces biochars with relatively high content of inorganic elements. Indirectly heated biochars are compliant with the European Biochar Certificate regarding the carbon content, O/C ratio, H/C ratio. Our biochars may provide an improvement in agricultural yield and CO2 adsorption, especially those produced under air/steam gasification conditions. Our novel indirect design not only constitutes a promising development in the field of biomass allothermal gasification but also can help improving gasification circularity through the production of high quality biochar.

In this paper, we investigate the long-term adhesion strength and barrier property of our recently proposed encapsulation stack that includes PDMS-Parylene C and PECVD interlayers (SiO 2 and SiC) for adhesion improvement. To evaluate the adhesion strength of our proposed stack, the sample preparation consisted in depositing approximately 25 nm of SiC and 25 nm of SiO 2 on half wafers, previously coated with Parylene C. Next, $50 \mu \mathrm{m}$ PDMS was spin-coated on top. Finally, the samples were detached from the Si wafer and soaked in a PBS solution at 67°C to accelerate the aging process. Two samples were also implanted, subcutaneously, on the left and right subscapular regions of a rat. The optical inspection and peel tests performed after two months confirmed our preliminary findings and showed a significant improvement of the adhesion in our proposed encapsulation stack compared to the case of PDMS on Parylene C alone. In addition, the X-ray photoelectron spectroscopy(XPS) analysis at the interface between SiC and Parylene C showed different peaks for the interface compared to the reference spectra, which could be an indication of a chemical bond. Finally, water vapor transmission rate (WVTR) tests were performed to investigate the barrier property of our proposed encapsulation stack against water vapor transmission. The results demonstrated that the proposed stack acts as a significantly (two orders of magnitude) higher barrier against moisture compared to only Parylene C and PDMS encapsulation layers. The proposed method yields a fully transparent encapsulation stack over a broad wavelength spectrum that can be used for the conformal encapsulation of flexible devices and thus, making them compatible with techniques such as optical imaging and optogenetics.

Lithium salts have been proposed as promising environmentally friendly alternatives to carcinogenic hexavalent chromium-based inhibitors for the corrosion protection of aerospace aluminium alloys (AAs). Incorporated into organic coatings, lithium salts are released at damaged locations to establish a conversion layer in which distinct sublayers have different barrier characteristics. Thus, detailed knowledge on the sequence of formation events from the early stages of nucleation towards the final multi-layered arrangement is essential for developing and optimising lithium-leaching technology for protective coatings. Here, liquid-phase-transmission electron microscopy (LP-TEM) is employed to observe nanoscopic morphological evolutions in situ during the lithium-based conversion process of AA2024-T3. Thanks to dedicated preparation of delicate sandwiched TEM specimens allowing us to explore the events cross-sectionally, we provide real-time direct mechanistic information on the conversion process from the initiation to an advanced growth stage. In parallel, we perform supplementary ex situ SEM and TEM investigations to support and validate the LP-TEM findings. The unprecedented experimental approach developed and executed in this study provides an inspiring base for studying also other complicated surface conversion processes in situ and at the nanoscopic scale.

The mission of an advanced epoxy-based nanocomposite coating is to provide a given substrate with protection against an unwelcome guest; e.g. corrosive molecules/media, environmental stress, flame, thermal degradation or microorganisms. In such systems, the degree to which superior properties can be guaranteed depends on the state of network formation in the epoxy in the presence of nanoparticles. For low-filled epoxy nanocomposite coatings, barrierity was taken as the main mechanism controlling over the efficiency of corrosion inhibition in the coating against oxygen or other corrosive moieties, whilst in highly-loaded nanocomposites one should take a closer look at both physical and chemical interaction between the resin and nanoparticles. In this sense, epoxy/Fe3O4 systems were studied here as model nanocomposite coatings and their anti-corrosion and flame retardancy potentials were patterned in terms of qualitative cure analysis made in terms of Cure Index. Anti-corrosion and flame retardancy properties of the aforementioned nanocomposite coatings were mechanistically described at either low or high loading levels in view of Cure Index for postulates of structure-properties association in advanced nano-Fe3O4 incorporated epoxy nanocomposite coatings. We hope that speculations and visulizations provided here about structure-properties relationships are useful to be used in open discussions between experts in the hope of generalization to complex systems containing different types of nanoparticles whatever surface functionality.

Additively manufactured (AM) biodegradable magnesium (Mg) scaffolds with precisely controlled and fully interconnected porous structures offer unprecedented potential as temporary bone substitutes and for bone regeneration in critical-sized bone defects. However, current attempts to apply AM techniques, mainly powder bed fusion AM, for the preparation of Mg scaffolds, have encountered some crucial difficulties related to safety in AM operations and severe oxidation during AM processes. To avoid these difficulties, extrusion-based 3D printing has been recently developed to prepare porous Mg scaffolds with highly interconnected structures. However, limited bioactivity and a too high rate of biodegradation remain the major challenges that need to be addressed. Here, we present a new generation of extrusion-based 3D printed porous Mg scaffolds that are coated with MgF2 and MgF2-CaP to improve their corrosion resistance and biocompatibility, thereby bringing the AM scaffolds closer to meeting the clinical requirements for bone substitutes. The mechanical properties, in vitro biodegradation behavior, electrochemical response, and biocompatibility of the 3D printed Mg scaffolds with a macroporosity of 55% and a strut density of 92% were evaluated. Furthermore, comparisons were made between the bare scaffolds and the scaffolds with coatings. The coating not only covered the struts but also infiltrated the struts through micropores, resulting in decreases in both macro- and micro-porosity. The bare Mg scaffolds exhibited poor corrosion resistance due to the highly interconnected porous structure, while the MgF2-CaP coatings remarkably improved the corrosion resistance, lowering the biodegradation rate of the scaffolds down to 0.2 mm y-1. The compressive mechanical properties of the bare and coated Mg scaffolds before and during in vitro immersion tests for up to 7 days were both in the range of the values reported for the trabecular bone. Moreover, direct culture of MC3T3-E1 preosteoblasts on the coated Mg scaffolds confirmed their good biocompatibility. Overall, this study clearly demonstrated the great potential of MgF2-CaP coated porous Mg prepared by extrusion-based 3D printing for further development as a bone substitute. This journal is

The initiation of corrosion can be triggered by defects in the adsorbed layer of organic inhibitors. A detailed knowledge of the intermolecular forces between the inhibitor molecules and the interfacial bonding will be decisive to unravel the mechanisms driving the corrosion initiation. In this work, adsorbed organic layers of 2-mercapto-5-methoxybenzimidazole (SH-BimH-5OMe) and 5-amino-2-mercaptobenzimidazole (SH-BimH-5NH2) were compared regarding their performance mitigating copper corrosion. Atomic force microscopy was used to address the stability and intermolecular forces of the self-assembled monolayers, using imaging and force measurement modes. For a film formed by amino-derivative molecules, a gold-coated tip frequently picked up individual molecules (molecular fishing) in force-distance measurements. For layers of the methoxy-derivative, no fishing events were observed, pointing to a constant functional layer. X-ray photoelectron spectroscopy revealed that SH-BimH-5OMe molecules form a stronger bond with the surface and more stable SAM layers on Cu surfaces as compared to SH-BimH-5NH2 molecules. Results of computational density functional theory modeling and electrochemical corrosion tests are in line with the microscopy and spectroscopy results. In particular, with aid of computational modeling the less ordered structure of the SH-BimH-5NH2 monolayer is attributed to dual bonding ability of SH-BimH-5NH2 that can adsorb with either S or NH2 groups., info:eu-repo/semantics/published

Additively manufactured biodegradable porous iron has been only very recently demonstrated. Two major limitations of such a biomaterial are very low biodegradability and incompatibility with magnetic resonance imaging (MRI). Here, we present a novel biomaterial that resolves both of those limitations. We used extrusion-based 3D printing to fabricate ex situ-alloyed biodegradable iron-manganese scaffolds that are non-ferromagnetic and exhibit enhanced rates of biodegradation. We developed ink formulations containing iron and 25, 30, or 35 wt% manganese powders, and debinding and sintering process to achieve Fe-Mn scaffolds with 69% porosity. The Fe25Mn scaffolds had the ε-martensite and γ-austenite phases, while the Fe30Mn and Fe35Mn scaffolds had only the γ-austenite phase. All iron-manganese alloys exhibited weakly paramagnetic behavior, confirming their potential to be used as MRI-friendly bone substitutes. The in vitro biodegradation rates of the scaffolds were very much enhanced (i.e., 4.0 to 4.6 times higher than that of porous iron), with the Fe35Mn alloy exhibiting the highest rate of biodegradation (i.e., 0.23 mm/y). While the elastic moduli and yield strengths of the scaffolds decreased over 28 days of in vitro biodegradation, those values remained in the range of cancellous bone. The culture of preosteoblasts on the porous iron-manganese scaffolds revealed that cells could develop filopodia on the scaffolds, but their viability was reduced by the effect of biodegradation. Altogether, this research marks a major breakthrough and demonstrates the great prospects of multi-material extrusion-based 3D printing to further address the remaining issues of porous iron-based materials and, eventually, develop ideal bone substitutes. Statement of significance: 3D printed porous iron biomaterials for bone substitution still encounter limitations, such as the slow biodegradation and magnetic resonance imaging incompatibility. Aiming to solve the two fundamental issues of iron, we present ex-situ alloyed porous iron-manganese scaffolds fabricated by means of multi-material extrusion-based 3D printing. Our porous iron-manganese possessed enhanced biodegradability, non-ferromagnetic property, and bone-mimicking mechanical property throughout the in vitro biodegradation period. The results demonstrated a great prospect of multi-material extrusion-based 3D printing to further address the remaining challenges of porous iron-based biomaterials to be an ideal biodegradable bone substitutes.

The design of sacrificial cathodic protection (CP) systems conventionally involves steady-state assumptions, which means design parameters are considered constant during the in-service life of CP systems. In contrast, it is evident by experimental observations (including field measurements) that cathodic protection is a transient process due to variations in electrolyte properties such as seasonal changes in electrical conductivity of soil, depletion of anodes, and formation of corrosion deposits on anode material surface, to name a few. The lack of practical time-dependent models on this critical issue is apparent in the literature; accordingly, in this study, a pseudo transient electrochemical model is adopted to highlight the transient behavior of cathodic protection systems and investigate key differences with steady-state behavior. For the sake of demonstration, the developed model is used to simulate the time-dependent performance of a sacrificial anode bed for cathodic protection of screw-pile foundations. The methodology proposed in this study can be used by corrosion engineers to improve and optimize the design of CP systems and numerically estimate the performance of sacrificial anodes and the level of protection over time.

Efficiency of corrosion inhibitors in aqueous solutions depends on several interfacial parameters, which may vary over time. Therefore, reliable electrochemical techniques are demanded for screening the efficiency of corrosion inhibitors and monitoring their performance over time. Here, we evaluate corrosion inhibition efficiency of imidazole-based compounds on bare Cu surfaces and highlight the importance of electrochemical evaluation of the inhibitor over time, characterized by linear polarization resistance techniques as a reliable, instantaneous and non-invasive method for assessing intrinsic inhibitor performance in lab screening studies.

This paper investigates the root cause of a failure in gas-turbine blades, made of Nimonic-105 nickel-based superalloy. The failure was reported in two blades in the second stage of a turbine-compressor of a gas turbine in the hot section. Two failed blades were broken from the root and from the airfoil. The failure took place after 20 k h of service exposure in the temperature range 700−850 °C, with the rotating speed being in the range 15,000−16,000 rpm. The microstructures of the failed blades were studied using optical/electron microscopes. Energy dispersive X-ray spectroscopy (EDS) was employed for phase identification. Results showed that failure first initiated from the root. The dominant failure mechanism in the root was concluded to be corrosion-fatigue. The failure scenario was suggested based on the results obtained.

Dealloying is involved in materials science responsible for fabrication of nanoscale structures beneficially but for corrosion degradations detrimentally. Detailed understanding related to the latter is critical for designing corrosion-resistance alloys and dedicated inhibition systems. Thus, direct nanoscopic observations of nano-structural and compositional evolutions during the process are essential. Here using liquid phase-transmission electron microscopy (LP-TEM), for the first time, we show dynamic evolution of intricate site-specific local corrosion linked to intermetallic particles (IMPs) in aerospace aluminium alloys. To thoroughly probe degradation events, oxidation direction is controlled by purposefully masking thin specimens, allowing for observing top-view surface initiation to cross-sectional depth propagation of local degradations. Real-time capturing validated and supported by post-mortem examinations shows a dealloying-driven process that initiates at IMPs and penetrates into the depth of the alloy, establishing macroscopic corrosion pits. Besides, controversial mechanisms of noble-metal redistribution are finally elucidated.

Internal and external magnetic fields due to pressure-driven ionic currents inside a two- dimensional nanoslit are obtained theoretically and numerically by finite element solution of governing equations, i.e. , Poisson-Nernst-Planck, Ampere, and Navier-Stokes equations. The transport governing equations in this study are non-dimensionalized by Debye screening length, and discretized in a two dimensional finite length nanoslit. The magnetic field components have opposite signs above and below the nanoslit due to opposite directions of the Amperian closed path. Within the nanoslit the non-uniformity of ionic currents resulted in non-uniform magnetic fields however outside the nanoslit, magnetic fields remain relatively constant, independent of the distance from a sufficiently long and wide nanoslit. It is anticipated that non-invasive ionic/streaming current measurements can be conducted by external magnetic fields readouts in sufficiently long and wide nanoslits. For instance, to estimate electrical properties (zeta potential) of solid-liquid interface, and to accurately sequence DNA and biomolecules.

This work investigates the synergetic effect of zinc aluminum polyphosphate (ZAPP) and 2-mercaptobenzimidazole (MBI) on the corrosion protection of mild steel coated with a solvent-borne epoxy-polyamide layer. The magnitude and trend of electrochemical impedance spectroscopy data over 70-d immersion in 3.5 wt.% NaCl solution indicate superior corrosion protection of the combined inhibitors compared to those containing either just ZAPP or MBI. Pull-off tests show that the combined inhibitor system provides an improved adhesion strength. The enhanced corrosion performance is correlated to precipitation of a protective layer at the coating/metal interface verified by SEM and electrochemical studies upon exposure to electrolytes.

Formation of hemispherical pom-pom-like clusters of nanowires during potentiostatic oxidation of copper in NH4HCO3 is reported. High-purity copper was oxidized in a three-electrode setup at constant electrode potential ranging from 200 mV to 1000 mV vs. Ag|AgCl|sat. KCl for 14 h. The obtained clusters of nanwires were examined using FE-SEM, XRD and XPS techniques. The diameter of nanowires, composed mainly of CuO, Cu2O, Cu(OH)2, and Cu4O3, was ca. 50–70 nm. The diameter of the clusters strongly depends both on the applied potential and the time of electrooxidation, and was found to be in the range of 1–3 μm. The mechanism for the formation of such nanowires clusters is proposed.

A major challenge in transistor technology scaling is the formation of controlled ultrashallow junctions with nanometer-scale thickness and high spatial uniformity. Monolayer doping (MLD) is an efficient method to form such nanoscale junctions, where the self-limiting nature of semiconductor surfaces is utilized to form adsorbed monolayers of dopant-containing molecules followed by rapid thermal annealing (RTA) to diffuse the dopants to a desired depth. Unlike ion implantation, the process does not induce crystal damage, thus making it highly attractive for nanoscale transistor processing. To date, reported MLD processes have relied on solution processing for monolayer formation. Gas-phase processing, however, benefits from higher intra- and interwafer uniformity and conformal coverage of 3D structures and is more desirable for manufacturing. In this regard, we report a new approach for MLD in silicon and germanium using gas-phase monolayer formation. We call this technology gas-phase monolayer doping (GP-MLD). This method relies on sequential pulse-purge cycles of gas-phase dopant-containing molecules to form a boron- or phosphorus-containing monolayer on a target semiconductor surface. Here, we show the feasibility of our approach through the formation of ultrashallow B- and P-doped junctions on Si and Ge surfaces. The mechanism of adsorption is characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Sub-5 nm junction depths with high dopant dose are obtained as characterized by secondary ion mass spectrometry and sheet resistance measurements. Additionally, we demonstrate that area selectivity can be achieved via lithographic patterning of the monolayer dopants before the diffusion step. The results demonstrate the versatility of the GP-MLD approach for formation of controlled and ultrashallow junctions.

This paper investigates a severe microbiologically influenced failure in the elbows of a buried amine pipeline in a petrochemical plant. Pipelines can experience different corrosion mechanisms, including microbiologically influenced corrosion (MIC). MIC, a form of biodeterioration initiated by microorganisms, can have a devastating impact on the reliability and lifetime of buried installations. This paper provides a systematic investigation of a severe MIC-related failure in a buried amine pipeline and includes a detailed microstructural analysis, corrosion products/biofilm analyses, and monitoring of the presence of causative microorganisms. Conclusions were drawn based on experimental data, obtained from visual observations, optical/electron microscopy, and Energy-dispersive X-ray spectroscopy (EDS)/X-Ray Diffraction (XRD) analyses. Additionally, monitoring the presence of causative microorganisms, especially sulfate-reducing bacteria which play the main role in corrosion, was performed. The results confirmed that the failure, in this case, is attributable to sulfate-reducing bacteria (SRB), which is a long-known key group of microorganisms when it comes to microbial corrosion.

In this paper, a post superacid (SA) treatment was proposed to enhance the performance of InAs FinFETs on SiO2/Si substrates. Typically, the subthreshold swing (SS) has reduced from 217 to 170 mV/decade and the transconductance ( ${g}_{m}$ ) has increased from 6.44 to 26.5 $\mu \text{S}/\mu \text{m}$ after SA treatment. It was found that the interfacial In2O3 at the InAs/ZrO2 interface was effectively reduced after SA treatment due to the strong protonating nature of the SA solution. As a result, the interface trap density was reduced leading to a pronounced reduction of sheet resistance after SA treatment. The modeling of transfer characteristics indicates that the carrier mobility is enhanced by 5.8~7.1 folds after SA treatment due to interfacial traps reduction. The results suggest that SA treatment can be potentially extended to other III–V MOSFETs to enhance the device performances.

This paper investigates a failure in convection section tubes of a gas heater unit in a petrochemical plant. Tubes are made of AISI 304 stainless steel. The failure is reported after 5 years of service at working temperature 500 &deg, C. The failure is in the form of circumferential cracks in the vicinity of the weld. Various characterization techniques, including optical and electron microscopes as well as energy-dispersive X-ray spectroscopy (EDS), were used to study the failure. Results showed that that the damage has initiated in the heat affected zone (HAZ) area parallel to the weld/base metal interface. Cracks have propagated alongside grain boundaries, resulting in an intergranular fracture. The main cause of failure was concluded to be attributable to the grain boundary sensitization and intergranular grain boundary attack due to improper welding and long time exposure of tubes to high temperature. Possible mitigation strategies to minimize similar failures will be discussed.

The influence of silane treated nano zinc oxide (nZnO) on the protection, photocatalytic properties and interfacial interactions in acrylic/carbon steel systems was investigated. For this purpose, nZnO particles have been synthesized using microwave irradiation method. The morphology of synthesized zinc oxide nanoparticles was studied by scanning electron microscopy (SEM). The nZnO were treated by 3(2-amino ethyl amino) propyl trimethoxysilane. Fourier transforms infrared spectroscopy (FTIR) and thermogravimetry (TGA) techniques have been used to prove success of nZnO surface modification. In the next step, nanocomposites were prepared and coated on carbon steel by dip-coating method. Corrosion resistances of coatings were evaluated by electrochemical impedance spectroscopy (EIS). Field emission scanning electron microscopy (FE-SEM) has been carried out to study morphology of cross section of films. Moreover, to study the hydrophillicity and photocatalytic properties of coating surface, contact angle of the nanocomposites coating surface have been measured. Finally interfacial adhesion and their mechanisms have been studied by molecular dynamics (MD) and first principle quantum mechanics (QM) simulation method.

This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer edge of the disc brake. The cracks were rather straight with no branching. Optical microscope, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of the samples. Results showed that the root cause of crack formation, in this case, was related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wear, were recognized in the failed specimen. Moreover, the worn surface in some areas was covered with fine oxide particles. These particles appeared to have a significant contribution toward abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on the samples. Results of the pin-on-disc experiments were compared and correlated to the results obtained from the failed brake disc.

The often used simplistic correlations between molecular electronic parameters and experimentally determined corrosion inhibition efficiencies are critically evaluated for a set of 24 heterocyclic organic compounds, tested as corrosion inhibitors for copper in 3 wt.% NaCl aqueous solution. Twelve different molecular electronic descriptors—such as ionization potential, electron affinity, HOMO–LUMO gap, dipole moment—are tested and it is shown that none of them displays any noticeable correlation with the inhibition efficiency. Our results, therefore, cast serious doubt on reported correlations between such parameters and inhibition efficiency, obtained for only a few inhibitors, which are abundant in the literature. We also discuss some pros and cons of inhibition efficiency as a metric for evaluating the performance of corrosion inhibitors, and introduce a new metric termed inhibition power that uses the universal logarithmic scale and dimensionless decibel (dB) units., info:eu-repo/semantics/published

The aim of this work is to discuss the photocatalytic performance of the titania-zirconia porous photocatalyst layers synthesized via micro arc oxidation technique. An attempt was also made to put forward the basic formation mechanism of the layers. Impedance and optical properties of the photocatalyst layers were studied by electrochemical impedance spectroscopy (EIS), Photoluminescence spectroscopy and UV–vis absorption spectroscopy, in order to assess their intrinsic catalytic properties. The results of the EIS were correlated with the microstructural characteristics along with measurements of Methylene Blue (MB) photocatalytic degradation. The results show enhanced photocatalytic activity of TiO2-ZrO2 composite layers compared to pure TiO2 layer. It was revealed that the photocatalytic activity of the layers prepared at different duty cycles is influenced by characteristics of microdischarge regime imposed by working electrolytes with varying additive concentration. The results of photocatalytic degradation of methylene blue were in good agreement with those obtained from electrochemical analysis.

The replacement of chromate-based corrosion inhibitors is a requirement for the aerospace sector. New developments demand additional studies to find synergistic combinations of inhibiting species. This paper discusses the synergistic effect resulting from various corrosion inhibitor mixtures proposed for the corrosion protection of aluminum alloy 2024-T3. The corrosion inhibition efficiency and the synergistic factors were determined for AA2024-T3 coupons immersed in 0.05 M NaCl solutions, containing either a single inhibitor or binary combinations of inhibitors. The following inhibitors were tested: Ce 3 + , 8-hydroxyquinoline (8HQ), salicylaldoxime (SAL), and 2,5-dimercapto-1,3,4-thiadiazolate (DMTD). Electrochemical impedance spectroscopy (EIS) and ATR-FTIR in Kretschmann geometry were used to evaluate the chemical and electrochemical variations during the exposure of bare coupons to inhibitor-containing NaCl solutions. The results allowed calculating the synergistic effect for binary mixtures and the most effective mixtures were those containing 8HQ-SAL and DMTD-8HQ. The synergistic effect was also determined for coated coupons. A water-based epoxy coating was modified with calcium carbonate microparticles, loaded beforehand with single inhibitors or with binary mixtures. EIS measurements were performed in 0.5 M NaCl and the results revealed that the epoxy coatings modified with CaCO 3 microparticles, loaded with inhibitor mixtures, provided enhanced corrosion protection. The most effective corrosion protection was observed for two mixtures: CaCO 3 (8HQ + SAL) and CaCO 3 (Ce + SAL). Interestingly, the results revealed that the synergistic effect on bare AA2024-T3 can be different from the situation where the same inhibitor mixtures are used in smart, anti-corrosive coatings.

Molybdenum disulfide (MoS2) has been widely examined as a catalyst containing no precious metals for the hydrogen evolution reaction (HER); however, these examinations have utilized synthesized MoS2 because the pristine MoS2 mineral is known to be a poor catalyst. The fundamental challenge with pristine MoS2 is the inert HER activity of the predominant (0001) basal surface plane. In order to achieve high HER performance with pristine MoS2, it is essential to activate the basal plane. Here, we report a general thermal process in which the basal plane is texturized to increase the density of HER-active edge sites. This texturization is achieved through a simple thermal annealing procedure in a hydrogen environment, removing sulfur from the MoS2 surface to form edge sites. As a result, the process generates high HER catalytic performance in pristine MoS2 across various morphologies such as the bulk mineral, films composed of micron-scale flakes, and even films of a commercially available spray of nanoflake MoS2. The lowest overpotential (η) observed for these samples was η = 170 mV to obtain 10 mA/cm(2) of HER current density.

Transition metal dichalcogenides (TMDCs) have been extensively explored for applications in electronic and optoelectronic devices due to their unique material properties. However, the presence of large contact resistances is still a fundamental challenge in the field. In this work, we study defect engineering by using a mild plasma treatment (He or H2) as an approach to reduce the contact resistance to WSe2. Material characterization by X-ray photoelectron spectroscopy, photoluminescence, and Kelvin probe force microscopy confirm defect-induced n-doping, up to degenerate level, which is attributed to the creation of anion (Se) vacancies. The plasma treatment is adopted in the fabrication process flow of WSe2 n-type metal-oxide-semiconductor field-effect transistors to selectively create anion vacancies at the metal contact regions. Due to lowering the metal contact resistance, improvements in the device performance metrics such as a 20× improvement in ON current and a nearly ideal subthreshold swing value of 66 mV/dec are observed. This work demonstrates that defect engineering at the contact regions can be utilized as a reliable scheme to realize high-performance electronic and optoelectronic TMDC devices.

Optoelectronic devices based on two-dimensional (2D) materials have shown tremendous promise over the past few years; however, there are still numerous challenges that need to be overcome to enable their application in devices. These include improving their poor photoluminescence (PL) quantum yield (QY) as well as better understanding of exciton-based recombination kinetics. Recently, we developed a chemical treatment technique using an organic superacid, bis(trifluoromethane)sulfonimide (TFSI), which was shown to improve the quantum yield in MoS2 from less than 1% to over 95%. Here, we perform detailed steady-state and transient optical characterization on some of the most heavily studied direct bandgap 2D materials, specifically WS2, MoS2, WSe2, and MoSe2, over a large pump dynamic range to study the recombination mechanisms present in these materials. We then explore the effects of TFSI treatment on the PL QY and recombination kinetics for each case. Our results suggest that sulfur-based 2D materials are amenable to repair/passivation by TFSI, while the mechanism is thus far ineffective on selenium based systems. We also show that biexcitonic recombination is the dominant nonradiative pathway in these materials and that the kinetics for TFSI treated MoS2 and WS2 can be described using a simple two parameter model.

In this work, we introduce an efficient methodology to assess the delamination mechanism of epoxy coating from steel substrate combining spectroscopic and analytical techniques. To reflect the competence of this approach, different samples were prepared by applying epoxy/polyaminoamide layers on untreated, acid and alkaline pretreated substrates. The results obtained from XPS and energy dispersive X-ray analyses describe delamination of the coatings on differently pretreated surfaces during the pull-off test. EIS measurements demonstrated that acid treatment improves the resistance against cathodic delamination, while XPS analysis provided useful data about coating delamination from the substrate.

Aluminium alloy 2024-T3 (AA2024-T3), widely applied in aerospace industries, may suffer from severe localized corrosion as a result of its relatively complex and heterogeneous microstructure. The corrosion initiation in such a critical alloy is governed by dynamic processes that take place at the nanoscale. A thorough understanding of the sequential stages of corrosion initiation is of pivotal importance to developing efficient inhibition strategies and demands high resolution techniques along with the ability of real-time recording of nanoscopic events. However, to date, it has not yet been possible to unambiguously show the morphological and electrochemical characteristics during local corrosion of AA2024-T3. In particular, local corrosion initiation linked to nano-/microstructural heterogeneities, intermetallic particles (IMPs), take place relatively fast and at the nanoscopic scale, rendering the study of the early stages of corrosion experimentally virtually impossible until now. Herein, we show, for the first time, the dynamic evolution of site-specific local corrosion of AAs from early surface initiation to depth propagation at the nanoscale using a dedicated in-situ liquid phase-transmission electron microscopy (LP-TEM) experimental facility. Transmission electron microscopy (TEM), capable of revealing microstructural and compositional variations in alloys at atomic and nanoscopic scale, has been applied widely in corrosion studies but mostly ex-situ and quasi in-situ. These approaches are not straightforward as artefacts and contaminations might be introduced into the system during the ex-situ and quasi in-situ experiments, including dehydration of surfaces and therefore may not fully represent the real conditions. With recent technological advances, thanks to the development of dedicated microelectronic mechanical systems (MEMS), it is now possible to fabricate components like nanoreactors (NRs) to study complicated corroding systems at the nanoscale in-situ. In fact, NRs employed in TEM studies enable to monitor morphological and compositional evolutions in materials in-situ as a result of interaction with aggressive environments like a gas or liquid. In this study, we put efforts into providing direct evidence for the nanoscopic role of intermetallics in AA2024-T3 localized corrosion through quasi in-situ TEM and in-situ LP-TEM approaches. Quasi in-situ studies were implemented by intermittently exposing the Argon ion-milled thin samples to 0.01 M NaCl solution. For in-situ LP-TEM, the real TEM specimens (lamellae) were first fabricated out of regions of interest with a FEI Helios focused ion beam. Then, the lamellae were transferred successfully to home-made NRs using an easy-lift technique. The NRs, equipped with an electrochemical set-up, were specially designed for corrosion studies. A Cs-corrected FEI Titan TEM was employed to perform real-time studies in scanning TEM (STEM) mode. Although a good resolution is still a major challenge for in-situ LP-TEM, the results revealed that intermetallic phases regardless of their types are active and prone sites to localized corrosion attack themselves and the observations finally show and elucidate initial stages of IMP-induced pitting corrosion and copper redistribution mechanisms in AA2024-T3.

In this work, we synthesized carbon hollow spheres (CHSs) using the silica templating method, encapsulated 2-mercaptobenzimidazole (MBI) inhibitor in the CHSs and evaluated their corrosion inhibition performance upon exposure of mild steel to a saline solution containing the released inhibitor. The effects of silica template surface modification on the CHS structure was evaluated, while the structure and morphology of the synthesized CHS was analyzed using field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), Raman spectroscopy and X-ray diffraction (XRD) spectroscopy. Furthermore, thermogravimetric analysis (TGA), energy-dispersive X-ray spectroscopy mapping (EDS-mapping) and UV–vis were employed to evaluate the MBI release from carbon capsules at different pH values. Corrosion protection performance of the doped CHS was evaluated using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results showed tunability of the shell structure between an amorphous carbon and graphene structure using surface modification of the silica templates. Moreover, the MBI release from the CHSs showed to be pH-dependent allowing smart protection of mild steel when exposed to corrosive conditions.

Zirconium-based conversion treatment of zinc, aluminium and magnesium oxides have been studied in-situ using ATR-FTIR in a Kretschmann geometry. This set-up was coupled to an electrochemical cell, which allowed to obtain chemical and electrochemical information simultaneously as a function of conversion time. This elucidated the strong relation between physico-chemical surface properties and zirconium-based conversion kinetics. Whereas the surface hydroxyl density of zinc and aluminium increased during conversion, magnesium (hydr)oxide was shown to dissolve in the acid solution. Due to this dissolution, strong surface alkalization can be expected, explaining the rapid conversion kinetics. AES depth profiling was used to determine the final oxide thickness and elemental composition. This confirmed that magnesium is most active and forms a zirconium oxide layer approximately 10 times thicker than zinc. On the other hand, the presence of zirconium oxide on aluminium is very low and can be considered as not fully covering the metal oxide. Additionally, the converted oxide chemistry was related to the bonding mechanisms of amide functionalized molecules using ATR-FTIR and XPS. It was shown that inclusion of zirconium altered the acid-base properties, increasing the substrate proton donating capabilities in case of magnesium oxide and increasing hydrogen bonding and Bronsted interactions due to increased surface hydroxide fractions on zinc and aluminium substrates.

A phytoplasma was identified from symptomatic Babylon willow (Salix babylonica Linn) trees growing in urban areas in Isfahan, Yazd and Markazi provinces of Iran. Results of nested-PCR, sequencing and phylogenetic analysis indicated that the phytoplasma belongs to the ‘ Candidatus phytoplasma solani’ (16SrXII) taxonomic group.

An analytical model is proposed to describe the two-dimensional distribution of potential and current in planar electrodes of pouch-type lithium-ion batteries. A concentration-independent polarization expression, obtained experimentally, is used to mimic the electrochemical performance of the battery. By numerically solving the charge balance equation on each electrode in conjugation with the polarization expression, the battery behavior during constant-current discharge processes is simulated. Our numerical simulations show that reaction current between the electrodes remains approximately uniform during most of the discharge process, in particular, when depth-of-discharge varies from 5% to 85%. This observation suggests to simplify the electrochemical behavior of the battery such that the charge balance equation on each electrode can be solved analytically to obtain closed-form solutions for potential and current density distributions. The analytical model shows fair agreement with numerical data at modest computational cost. The model is applicable for both charge and discharge processes, and its application is demonstrated for a prismatic 20 Ah nickel-manganese-cobalt lithium-ion battery during discharge processes.

Citrus greening or Huanglongbing (HLB), a destructive disease of citrus worldwide, was reported from south of Iran in 2007. The molecular basis of compatibility and disease development in this system is poorly understood. We have carried out a cDNA-AFLP analysis to analyse gene expression of grapefruit infected by Candidatus Leiberibacter asiaticus in the late infection stage. We have applied a cDNA-AFLP approach on grafted infected grapefruit trees at the representing symptoms stage in susceptible host. Selective amplifications with 10 primer combinations allowed the visualization of approximately 24 transcript-derived fragments (TDFs) in the leaves of graft-inoculated trees, which were differentially expressed. We sequenced 14 fragments, which were identified as grapefruit transcripts after homology searching, whereas 12 were not homologous to sequences in NCBI databases. Many grapefruit genes spanning almost all functional categories were upregulated during infection, especially genes involved in ATP synthesize, cytochrome P450 synthesize, isoflavone 2'-hydroxylase, zeaxanthin epoxidase, cellulose synthase, DNA repair protein, aconitate hydratase 2 and citrus tristeza virus resistance gene. This study provides the first global catalogue of grapefruit genes expressed during inoculation, together with their functional annotations. This will help to elucidate the molecular basis of the resistance process and identify genes and chemicals that could help to inhibit the pathogen.