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For the first time, Zr702 coatings were deposited onto an Al6061 alloy using a high-pressure cold spray (HPCS) system. In this work, five different N2 process gas temperatures between 700 and 1100 °C were employed to understand the formation of cold sprayed (CS) Zr coatings and their feasibility for enhanced wear resistance. Results indicated that the N2 processing gas temperature of about 1100 °C enabled a higher degree of particle thermal softening, which created a dense, robust, oxide- and defect-free Zr coating. Across all CS Zr coatings, there was a refinement of crystallinity, which was attributed to the severe localized plastic deformation of the powder particles. The enhanced thermal boost up zone at the inter-particle boundaries and decreased recoverable elastic strain were accountable for the inter-particle bonding of the coatings at higher process gas temperatures. The flattening ratio (ε) increased as a function of temperature, implying that there was a greater degree of plastic deformation at higher N2 gas temperatures. The microhardness readings and wear volume of the coatings were also improved as a function of process gas temperature. In this work, the wear of the Al6061 alloy substrate was mainly plowing-based, whereas the Zr CS substrates demonstrated a gradual change of abrasive to adhesive wear. From our findings, the preparation of CS Zr coatings was a feasible method of enhancing the wear resistance of Al-based alloys.

Rapid screening of tuberculosis by evaluation of associated volatile organic biomarkers in breath is a promising technology that is significantly faster and more convenient than traditional sputum culture tests. Methyl nicotinate (MN) and methyl p-anisate (MPA) have been isolated as potential biomarkers for mycobacterium tuberculosis and have been found in the breath of patients with active pulmonary tuberculosis. A novel approach to detection of these biomarkers in liquid droplets (e.g. from breath condensate) using inexpensive screen-printed electrodes is presented. Previous modelling studies suggest that these biomarkers complex with certain transition metals of particular valence state. This interaction can be exploited by mixing the biomarker sample into an electroactive solution (EAS) containing the functional metal ion and observing the change electrochemically. The study focuses on low biomarker concentrations, determined to be clinically relevant based on preliminary GC-MS studies of the levels found in patient breath. It was found that both the cyclic voltammogram and square wave voltammogram of copper(II) change significantly when as little as 0.1 mM MN is added to the solution, with analysis times of less than 2 min. Copper(II) exhibits three separate peaks during square wave voltammetry. The location and area of each peak are affected differently as the concentration of MN increases, suggesting a reaction with specific oxidation states of the metal. In this way, a "fingerprint" method can be used to identify biomarkers once their known interaction is established.

Nanostructuring is a commonly employed method of obtaining superior mechanical properties in metals and alloys. Compared to conventional polycrystalline counterparts, nanostructuring can provide remarkable improvements in yield strength, toughness, fatigue life, corrosion resistance, and hardness, which is attributed to the nano grain size. In this review paper, the current state-of-the-art of synthesis methods of nanocrystalline (NC) materials such as rapid solidification, chemical precipitation, chemical vapor deposition, and mechanical alloying, including high-energy ball milling (HEBM) and cryomilling was elucidated. More specifically, the effect of various process parameters on mechanical properties and microstructural features were explained for a broad range of engineering materials. This study also explains the mechanism of grain strengthening using the Hall-Petch relation and illustrates the effects of post-processing on the grain size and subsequently their properties. This review also reports the applications, challenges, and future scope for the NC materials.

Additive manufacturing (AM) by laser powder bed fusion (LPBF) has gained significant research attention to fabricate complex 3D Inconel alloy components for jet engines. The strategic advantages of LPBF-based AM to fabricate jet components for aerospace applications are well reported. The jet components are exposed to a high degree of vibration during the jet operation in a variable aqueous environment. The combined vibration and the aqueous environment create a tribological condition that can accelerate the failure mechanism. Therefore, it is critical to understand the tribocorrosion behavior of the Inconel alloy. In the present work, tribocorrosion behavior of the LPBF fabricated standalone coating of Inconel 718 in the 3.5% NaCl aqueous solution is presented. The LPBF fabricated samples are analyzed to determine the impact of porosity, generated as a result of LPBF, on the triobocorrosion behavior of AM Inconel 718. The study includes potentiodynamic tests, cathodic polarization, along with OCP measurements. The corrosive environment is found to increase the wear by 29.24% and 49.5% without the initiation of corrosion in the case of AM and wrought Inconel 718, respectively. A corrosion accelerated wear form of tribocorrosion is observed for Inconel 718. Additionally, the corrosive environment has a significant effect on wear even when the Inconel 718 surface is in equilibrium potential with the corrosive environment and no corrosion potential scan is applied. This study provides an insight into a critical aspect of the AM Inconel components.

In this study, a compact cold sprayed (CS) Ti coating was deposited on Mg alloy using a +high pressure cold spray (HPCS) system. The wear and corrosion behavior of the CS Ti coating was compared with that of CS Al coating and bare Mg alloy. The Ti coating yielded lower wear rate compared to Al coating and Mg alloy. Electrochemical Impedance spectroscopy (EIS) and cyclic potentiodynamic polarization (CPP) tests revealed that CS Ti coating can substantially reduce corrosion rate of AZ31B in chloride containing solutions compared to CS Al coating. Interestingly, Ti-coated Mg alloy demonstrated negative hysteresis loop, depicting repassivation of pits, in contrast to AZ31B and Al-coated AZ31B with positive hysteresis loops where corrosion potential (Ecorr) &gt, repassivation potential (Erp), indicating irreversible growth of pits. AZ31B and Al-coated AZ31B were most susceptible to pitting corrosion, while Ti-coated Mg alloy indicated noticeable resistance to pitting in 3.5 wt % NaCl solution. In comparison to Al coating, Ti coating considerably separated the AZ31BMg alloy surface from the corrosive electrolyte during long term immersion test for 11 days.

Surface modification methods have been applied to metals and alloys to change the surface integrity, obtain superior mechanical properties, and improve service life irrespective of the field of application. In this review paper, current state-of-the-art of peening techniques are demonstrated. More specifically, classical and advanced shot peening (SP), ultrasonic impact peening (UIP), and laser shock peening (LSP) have been discussed. The effect of these techniques on mechanical properties, such as hardness, wear resistance, fatigue life, surface roughness, and corrosion resistance of various metals and alloys, are discussed. This study also reports the comparisons, advantages, challenges, and potential applications of these processes.

Microfluidic reactors have gained considerable interest for photocatalytic degradation of contaminants in water. These systems have advantages such as large surface-area-to-volume ratio and high control of fluid flow, yet still suffer from drawbacks due to limited mass transport associated with laminar flow. The use of titania nanotubes synthesized on a mesh substrate shows improved photocatalytic performance in comparison to nanotubes synthesized on a foil substrate in a microreactor. At the lowest flow rate (25 μL/min), the area normalized fractional conversion of methylene blue increased from 20% for foil to 46% in the case of nanotubes on mesh. The enhanced photocatalytic performance of the mesh is due to shorter diffusion distance and induction of flow perturbation. Also, the radially outward oriented nanotubes formed over the circumference of the titanium wire leads to the efficient capture of both reflected and refracted light. The device was also applied for inactivation of Escherichia coli O157:H7. At a flow rate of 50 μL/min, the titania nanotubes on a mesh microreactor were able to achieve >99% inactivation of E. coli under AM 1.5 (≈100 mW/cm2) simulated solar light.

In this research, cold sprayed Al coating layer on AZ31B Mg alloy was coated with cold sprayed Ti and Ta/Ti coatings, which noticeably reduced the wear rate of Al coated Mg alloy. Electrochemical corrosion tests and infinite focus 3D measurement results revealed that the high surface activity of commercially pure-Al coating, diffusion-controlled reactions, and formation of corrosion pits could be mitigated using Ti top coating. However, a dense layer of Ta on Ti coating exceptionally improved the corrosion resistance of Ti/Al coated AZ31B Mg alloy in neutral 3.5 wt.% NaCl solution This work gives a new strategy to considerably raise the wear and corrosion resistances of cold spray Al coated Mg alloys by double layered Ta/Ti coatings.

A synergistic combination of nanostructure synthesis and surface engineering was used to enhance the photoelectrochemical activity of titanium dioxide (TiO2) photoanodes. Titania nanotubular arrays were synthesized by electrochemical anodization of Ti thin foils. An atmospheric-pressure helium plasma followed by exposure to nitrogen was used to modify the surface properties of TiO2 nanotubes. The photocurrent from plasma-treated samples was approximately 25% higher than that from untreated samples. This increase in photoactivity could be ascribed to the following: 1) increased absorption of visible light due to bandgap reduction; 2) efficient charge separation; 3) production of optimal oxygen vacancies; and 4) increased surface area and, hence, enhanced electrode-electrolyte area to provide maximum optical adsorption and efficient charge transfer. The diffused reflectance Ultraviolet-visible (DR-UV-Vis) absorption spectra indicated a marginal increase in absorbance for the plasma-treated samples in the visible region, suggesting a change in surface electronic structure, although bulk electronic properties remain unchanged during plasma treatment.

The TiO 2 nanotubes have demonstrated potential in the photoelectrocatalytic degradation of methyl orange dye (MO). TiO 2 nanotubes were prepared using anodization of titanium foils in phosphoric acid (PA) and ethylene glycol (EG) by mechanical stirring and ultrasonic method. The TiO 2 nanotubes prepared in EG under ultrasound followed by annealing in nitrogen atmosphere showed higher activity towards dye degradation as compared to the stirring method. Dye degradation shows improved activity under an external bias compared to degradation performed in the absence of an external bias. An increase in the external bias from +0.0 to +0.1 V versus calomel electrode (SCE) is sufficient to improve the degradation rates of MO from 22% to 57% within the first 10 min. At +0.1 V, a complete degradation of 40 μM MO is observed within 30 min. The addition of oxidants such as oxygen and hydrogen peroxide demonstrate improvement in the MO degradation.

Anodization of Ti using fluoride containing polyhydric alcohols such as ethylene glycol or glycerol as electrolyte results in ordered arrays of TiO2 nanotubes with a smooth surface and a very high aspect ratio. However, the reproducibility of the result is affected by many experimental parameters, notably the water content. In this investigation, anodizations of Ti foil in anhydrous ethylene glycol +0.2 wt% NH4F solution (EG solution) with 0–1.0 wt% water additions were carried out at 20 V for 45 min in a dry-argon filled controlled-atmosphere glove box. It was observed that a minimum amount of 0.18 wt% of water addition was required to form a well ordered TiO2 nanotubular arrays. When the anhydrous EG solution was reused for third time, ordered arrays of nanotubes started to form. When the water addition to the EG solution was more than 0.5 wt%, formation of ridges was observed on the nanotubes. XPS results showed presence of un-anodized Ti element in the anhydrous condition and presence of organic and (NH4)2TiF6 type compounds in all the anodized samples in addition to the regular TiO2 phase. The results underline the influence of water content and local pH condition to form the ordered nanotubular arrays. Keywords: Nanotubular TiO2, Anodization, Ethylene glycol, Oxide film

Vertically oriented nanotubular TiO2 arrays were formed by a simple anodization process. Hydrogen storage studies were carried out on the TiO2 nanotubular arrays having different diameters by charging and discharging hydrogen with potentiostatic/galvanostatic control. The hydrogen storage capacities of the nanotubes were only marginally affected by the tube diameter. Concentration of oxygen vacancies as defects influenced the hydrogen storage of the nanotubes. Annealing of the TiO2 nanotubes in argon atmosphere increased the defect density and decreased the hydrogen discharge during initial charge–discharge cycles. Hydrogen storage studies through electrochemical route did not show significant storage capacity of TiO2 nanotubes. Diffusion of hydrogen as protons and interference of the double layer capacitance of nanotubes could be attributed to the lower hydrogen storage capacity.

INTRODUCTION Percutaneous device closure of atrial septal defect (ASD) has emerged as an alternative to traditional surgical closure. Although reduced hospital stay, decreased morbidity and absence of a surgical incision are beneficial, other procedure- or device-related complications are coming into light. We report a rare complication of early embolization of the Blockaid septal occluder into the main pulmonary artery bifurcation associated with 'aortic rim' erosion and present a brief review of literature pertaining to the high incidence of complications associated with deficient or eroded 'aortic rims' necessitating surgical intervention. MATERIALS AND METHODS An 18-year-old male underwent successful percutaneous device closure of a 24.5 mm ASD after fulfilling institutional criteria for the procedure. The device used was a Blockaid septal occluder, a device morphologically similar to the Amplatzer device. The subsequent day, he had embolization of the device into the main pulmonary artery bifurcation, and underwent emergency surgical retrieval of the same with closure of the ASD. At surgery the ASD was found to have an eroded aortic rim. COMMENTS We believe that embolization of the percutaneous septal occluder in our patient was due to a combination of factors including an inadequate aortic rim; a grossly oversized device which eroded the aortic rim; and the Blockaid septal occluder, whose formally untested design and configuration could have led to its migration. CONCLUSION Strict selection criteria governing an 'adequate' aortic rim, the size of the device, and the choice of the device may help reduce the incidence of complications like the rare, but potentially fatal embolization of the device into the pulmonary artery following percutaneous device closure of an ASD.

Scimitar syndrome is a rare variant of partial anomalous pulmonary venous connection. The combination of scimitar syndrome with anomalous connection of the left superior pulmonary vein to the left innominate vein is extremely rare, and is yet to be documented in literature. We report the successful single-stage correction of such a rare type of anomalous pulmonary venous connection.

Separation of fine coal particles from the associated mineral matter is achieved either by flotation or flocculation. Such a separation process relies on the surface modification of the components involved. Flotation is mainly accomplished with the addition of a suitable collector molecule to the coal slurry and flocculation makes use of synthetic flocculants such as polyacrylamide and polyethylene oxides. In the latter case, the interaction between coal particles and the polymer flocculant is considered to be non-specific and often results in inefficient flocculation. In the present study a microorganism, Mycobacterium phlei , has been used as a bioflocculant in the separation of combustibles from Illinois #6 and Kentucky #9 coals. This bacterium was reported to be negatively charged and highly hydrophobic. The flocculation phenomenon was explained based on the interactions between the coal particles and the bacteria. The results suggested that the hydrophobic interactions play a dominant role. The aggregated coal flocs were found to contain some pyrite and mineral matter due to similar settling velocities. However, improved separation of combustibles was accomplished by column flotation using a frother and nitrogen gas.

This paper provides an overview of the soil washing technology and briefly describes potential soil decontamination technologies.

The present study reports on the relationship between adsorption ofMycobacterium phlei onto hematite and flotation of the mineral. From light and scanning electron microscopy, contact angle and electrophoretic mobility observations it was found thatM. phlei is more negatively charged than hematite, that it readily accumulates onto the mineral and that it functions as a flotation collector for the mineral with optimum flotation taking place at about pH 2.5.

A pacing system infection may lead to infective endocarditis and systemic sepsis. Tricuspid valve surgery may be required if the valve is severely damaged in the process of endocarditis. Although, cardiopulmonary bypass is the safe choice for performing right-heart procedures, it may carry risk of inducing systemic inflammatory response and multi-organ dysfunction. Some studies have advocated TV surgery without institution of CPB. We report tricuspid valve excision using the off-pump inflow occlusion technique in a 68-year-old man. We also describe role of intra-operative TEE as a monitoring tool at different stages of the surgical procedure. .

The computer-based control and the implementation of an energy-efficient pressure cycle comminution technique for ore reduction are presented. The effects of various parameters, such as permeability, porosity, saturation time, and applied pressure, on process performance and modeling of a machine designed to reduce the particle size of porous material in tension through the use of rapid depressurization of water-saturated ore are discussed. In addition, the synergistic effect of surface energy modifiers and pressurization to achieve better performance is discussed. >

Objective: Homologous blood transfusion after open heart surgery puts a tremendous load on the blood banks. This prospective randomized study evaluates the efficacy of infusing back residual cardiopulmonary bypass (CPB) circuit i.e., pump blood as a means to reduce homologous transfusion after coronary artery bypass surgery (CABG) and whether its use increases postoperative drainage. Materials and Methods: Sixty-seven consecutive patients who underwent elective CABGs under CPB were randomized into 2 groups: (1) cases where residual pump blood was used and (2) controls where residual pump blood was not used. Patients were monitored for hourly drainage on the day of surgery and the 1 st postoperative day and the requirements of homologous blood and its products. Data were matched regarding change in Hemoglobin, Packed Cell Volume and coagulation parameters till 1st postoperative day. All cases were followed up for three years. Results: There was a marginal reduction in bleeding pattern in the early postoperative period in the cases compared to controls. The requirement of homologous blood and its products were also reduced in the cases. Conclusions: The use of CPB circuit blood is safe in the immediate postoperative period. The requirement of homologous blood transfusion can come down if strict transfusion criteria are maintained.

Postoperative studies in patients with chronic thromboembolic pulmonary hypertension (CTPH) have shown that pulmonary thromboembolectomy (PTE) results in a rapid decrease of right ventricular (RV) size, improvement in the RV systolic function and left ventricular (LV) diastolic function. However, the extent to which the biventricular function recovers immediately after embolectomy in post-cardiopulmonary bypass period is not clear. A 45-year-old male patient was operated for retrieval of thrombus from pulmonary trunk and right pulmonary artery. Intraoperative transesophageal echocardiography (TOE) before surgery revealed signs of RV dysfunction and enlargement. The interventricular septum was seen moving paradoxically during end-systole and early-diastole. E/A ratio on transmitral Doppler flow velocity profile was about 0.63 and S/D ratio on pulmonary venous Doppler profile was 2.25, indicative of LV diastolic dysfunction. After weaning the patient from bypass, navigation on TOE showed marginal recovery of the RV systolic function and abatement of septal paradox to some extent. However, significant improvement was observed in the LV diastolic parameter (normal E/A ratio, S/D ratio of 1.08). We conclude that the geometrically altered LV recovers more than the hypertrophied and hypokinetic RV in a patient with CTPH in the post-bypass period.

Adsorption of xanthates on galena, pyrite and sphalerite is presented as a function of oxygen concentration and pH. Oxygen concentration was varied from 0.21 to 29 ppm. Mechanisms of xanthate adsorption are suggested.

The application of microwaves has a demonstrated potential for the ultimate removal of water from fine coal. The electromagnetic energy absorption in coal during microwave drying is controlled by several factors, with dielectric properties being among the most important. In this paper, the measured dielectric properties of various ranks of coal are presented as a function of frequency and moisture content. A knowledge of the dielectric properties is essential in estimating the electromagnetic energy absorption in coal during microwave heating.

Gastrointestinal bleeding due to angiodysplasia of the large intestine associated with calcific aortic stenosis is a well-known entity. Angiodysplasias are artero-venous malformations and they form one of the common causes of occult gastro-intestinal bleeding in the elderly. A 59-year-old man underwent aortic valve replacement for severe aortic regurgitation, developed severe gastro intestinal bleeding. Selective angiography was inconclusive. Exploratory laparotomy revealed angiodysplasia of the terminal ileum, which was resected. We report this case to draw attention to this rare cause of gastro intestinal bleeding and the difficulty in arriving at a diagnosis by the usual investigations. q 2003 Elsevier B.V. All rights reserved.

The following describes the objectives of Project Activity 023 “Second Generation Waste Package Design Study” under DOE Cooperative Agreement DE-FC28-04RW12232. The objectives of this activity are: to review the current YMP baseline environment and establish corrosion testenvironments representative of the range of dry to intermittently wet conditions expected in the drifts as a function of time; to demonstrate the oxidation and corrosion resistance of A588 weathering steel and reference Alloy 22 samples in the representative dry to intermittently dry conditions; and to evaluate backfill and design features to improve the thermal performance analyses of the proposed second-generation waste packages using existing models developed at the University of Nevada, Reno(UNR). The work plan for this project activity consists of three major tasks: Task 1. Definition of expected worst-case environments (humidity, liquid composition and temperature) at waste package outer surfaces as a function of time, and comparison with environments defined in the YMP baseline; Task 2. Oxidation and corrosion tests of proposed second-generation outer container material; and Task 3. Second Generation waste package thermal analyses. Full funding was not provided for this project activity.

Superior type of sinus venosus atrial septal defect (SVASD) is invariably associated with the unroofing of right upper pulmonary vein (RUPV). Warden procedure and pericardial patch repair with rerouting of the RUPV are commonly performed operations for the superior SVASD. Both operations involve the risk of obstruction to the flow of superior vena cava or rerouted pulmonary vein in the postoperative period. The sinus venosus defects are well visualized on the transesophageal echocardiography (TEE) because of the proximity of the TEE probe to these structures. We are reporting two cases operated for the superior SVASD with unroofed RUPV, highlighting the intraoperative echocardiographic features before and after the surgery.

Delayed development of left ventricular pseudoaneurysm is a rare late complication of mitral valve prosthesis and requires early surgical intervention. Here we describe the occurrence of such a complication diagnosed 6-months after the valve surgery in a 60-year-old lady. The anatomic delineation of subannular left ventricular pseudoaneurysm using multiple imaging modalities including CT angiography is also being discussed.

Physical separation of bitumen from low-grade Utah tar sand deposits containing a relatively high viscosity bitumen phase (Sunnyside and Tar Sand Triangle deposits) has been accomplished by traditional size reduction and froth flotation techniques. At appropriate experimental conditions more than 90% of the bitumen can be recovered in a concentrate, containing more than 20 wt. % bitumen, which should be a suitable feed material for subsequent hot water or thermal processing. The efficiency of bitumen recovery depends on the extent of size reduction, as well as promoter and dispersant addition. Rejection of greater than 60% of the sand at ambient temperature and ease of water removal from the concentrate make such a process strategy both energy and cost effective. The energy required to achieve effective separation by the ambient temperature process is significantly less than the energy required for the recently developed hot water process which is being evaluated in a 100-tpd pilot plant this year. The flotation behaviour of the tar sand in this ambient temperature process has been correlated with contact angle measurements and the apparent point-of-zero-charge of the bitumen. The best flotation response at pH 7.8 to 9.0 occurs when the contact angle between the air bubble and bitumen surface is a maximum, corresponding to the apparent point-of-zero-charge of the bitumen as determined by titration.

FTIR spectroscopy has been used for the characterization of adsorbed oleate at the fluorite surface. It has been found that modest changes in the adsorption density at high temperature and high oxygen potential do not provide a satisfactory explanation for the significant increase in the hydrophobic character of the system under similar conditions. Rather, FTIR spectroscopic measurements suggest that chemical interaction between adsorbed oleyl groups occurs at high temperature and/or oxygen potential and accounts for the increased hydrophobicity. Specifically, the intensity of the CH bond of the adsorbed oleate diminishes at high temperature and/or high oxygen potential. Such a phenomenon was not observed in control tests with the calcium oleate soap. For extensive reaction at the fluorite surface, the presence of a new surface species has been identified. These results indicate that the fluorite surface catalyzes an oxidation and/or polymerization reaction between adsorbed oleyl groups which results in a more hydrophobic structure at the fluorite surface.

The effect of temperature and oxygen on the adsorption of oleate by fluorite was investigated in alkaline solution using a radiotracer technique. In these experiments, aqueous-phase precipitated calcium oleate was distinguished from surface oleate compounds and adsorption density was established as a function of system variables. The adsorption isotherms are characterized by three distinct regions: a chemisorbed plateau region; a surface calcium oleate precipitate region with significantly higher adsorption density reaching an adsorption maximum; and a third region, a region which exhibits a decrease in adsorption density at higher equilibrium oleate concentrations. Based upon the experimental evidence, adsorption seems to involve a chemisorbed layer at low equilibrium oleate concentrations which can be distinguished from a surface calcium oleate precipitate which forms at equilibrium concentrations exceeding 5 × 10 −6 M . Of greater importance, however, is the conclusion that these modest changes in adsorption density at higher temperatures and higher oxygen potentials do not provide a satisfactory explanation for the significant increase in hydrophobicity observed under similar conditions.