Surface Disruption Research Articles

Study of management of supracondylar femoral fracture using dynamic condylar screw

<p class="abstract"><strong>Background:</strong> Supracondylar femoral fracture poses a considerable therapeutic challenge. Operative treatment has become a standardized procedure. Stabilization has usually been achieved by an osteosynthesis with dynamic condylar screws or retrograde supracondylar nailing. In this article we are going to compare the results of surgical management of supracondylar nail and dynamic condylar screw. The aim is to study the effectiveness of dynamic condylar screw in surgical management of supracondylar fractures of femur.</p><p class="abstract"><strong>Methods:</strong> Prospective study of patients who had sustained supracondylar fracture of femur. The patients included in this study were those with supracondylar fractures of the femur with or without articular involvement and disruption of the joint surface. Study was done for a period of two and half years.<strong></strong></p><p class="abstract"><strong>Results:</strong> In our study of 21 cases, there were 8 patients (38%) who had associated fractures. Two patients were more than 50 yrs. 3 patients had compound injury which were grade-II of Gustilo Anderson classification. One of them developed post-operative infection and resulted in poor outcome. Other 2 patients had decrease range of movements resulted in fair outcome. Type C2 constituted highest number 8 (38%) followed by type A3 which was 28.5% i.e., 8 patients. Infection is observed in 9.5% of patients. 2 patients had implant failure and both were due to early weight bearing. In our study excellent and good results were found to be in 61.9%.</p><p class="abstract"><strong>Conclusions:</strong> Role of dynamic compression screw in the surgical management of supracondylar fractures of the femur minimizes the risk of complications.</p>

Effect of pulsed electric field on properties and multi-scale structure of japonica rice starch

Rice accounts for more than half the global population as staple food with starch predominating the major component. The effect of pulsed electric field (PEF) on thermal, paste and digestible properties, morphology, and hierarchical structure of rice starch in solid state was investigated. Upon PEF treatment, the gelatinization enthalpy (ΔΗ) of starch decreased, the retrogradation value of starch paste decreased slightly; and the rapid digestible starch (RDS) increased, the slowly digestible starch (SDS) decreased and the resistant starch (RS) changed slightly. PEF might act on the outer structure of starch granules, slightly changed the molecular structure of rice starch by rearranging the short-range structure and damaging the amorphous and crystalline structure. Pearson correlation analysis suggested that molecular weight of amylopectin, ΔΗ and digestibility were strongly dependent on the electric field strength; the changes in multi-scale structure was closely related to those in properties of PEF. The improvement of digestibility of rice starch might be attributed to the disruption of starch granule surface as evidenced by SEM observation and the rearrangement of multi-scale structures of rice starch induced by PEF.

Late Miocene birth of the Middle Jinsha River revealed by the fluvial incision rate

Abstract The Jinsha River has attracted considerable attention for nearly a century due to the morphology of its drainage basin. To explain the evolution of the Jinsha drainage basin, most researchers have considered that the present-day Jinsha (the upper reach of the Yangtze) was once a tributary of a single, southward-flowing river system called the Paleo-Red River, which drained into the South China Sea and was captured by the Upper Yangtze River, after which the flow direction changed to eastwards. The sudden disappearance, at 5.5 Ma, of the Red River submarine fan, which was fed primarily by the Paleo-Red River system, provides an important chronological constraint on the drainage reorganization and the capture event. However, until now, no geomorphic evidence has been presented to support this hypothesized age. Considering this problem, nine well-preserved terraces (T9 to T1) at Jinjiangjie in the Middle Jinsha River were evaluated in this study. To establish the chronological framework of these terraces, a combined dating approach was employed, incorporating electron spin resonance dating, cosmogenic nuclide (26Al/10Be) burial dating, and optically stimulated luminescence dating. We obtained a complete chronological sequence for terraces T9–T1, with ages of approximately 1.07 (T9), 0.70 (T8), 0.65 (T7), 0.51 (T6), 0.47(T5), 0.44(T4), 0.30 (T3), 0.18 (T2), and 0.047 (T1) Ma, respectively. Constrained by this framework, we calculated an average long-term fluvial incision rate of ~147 mm/ka. The reconstruction of the paleo-topography and paleo-drainage, based on digital elevation model data for the re-filling of the deeply incised river valley, indicates that the present drainage pattern in the Middle Jinsha system was established after the disruption of the paleo-landscape surface at an elevation of ~2000 m above sea level. The age of the present-day Middle Jinsha drainage was determined at approximately 5.5 Ma by extrapolating the average valley incision rate, suggesting that the present-day Jinsha was formed at about this time. Our results agree with the previously estimated timing of the disappearance of the Red River submarine fan.

Accelerated solution-phase exchanges minimize defects in colloidal quantum dot solids

Colloidal quantum dots (CQDs) are promising for solar cell applications in view of their low cost, solution processing, and bandgap tuning. Solution-phase ligand exchange is one successful strategy to realize dense CQD solids with minimized inhomogeneous broadening and enhanced carrier transport. In this process, long alkane ligands are replaced with short metal-halide ligands during a phase-transfer from a non-polar to a polar solvent. Unfortunately, these two processes – ligand exchange and phase transfer – possess very different kinetic rates. We hypothesized that this kinetic rate mismatch could lead to CQD surface disruption and to the formation of unpassivated sites and dangling bonds, contributing in turn to sub-bandgap trap states. Here we present a ligand exchange that favors a rapid (seconds, instead of minutes or hours) surface modification and phase transfer that minimizes surface exposure during phase-transfer. We accelerate the exchange dynamics by using highly concentrated alkane-capped CQD solutions, maximizing the contact area of CQD surfaces with incoming halide ligands to achieve enhanced exchange rates. Using this strategy, we achieve improved photoluminescence quantum yield (from 22% to 32%), sharper bandtails (from 38 meV to 17 meV), and realize CQD photovoltaic cells with enhanced open-circuit voltage (0.670 V vs. 0.650 V of control), fill factor, and power conversion efficiency (12.1% vs. 11.0% in the control).

Veterinary ocular microbiome: Lessons learned beyond the culture.

Ocular pathogens cause many painful and vision-threatening diseases such as infectious keratitis, uveitis, and endophthalmitis. While virulent pathogens and pathobionts play important roles in disease pathogenesis, the scientific community has long assumed disruption of the ocular surface occurs prior to microbial colonization and subsequent infection. While nonpathogenic bacteria are often detected in corneal and conjunctival cultures from healthy eyes, cultures also frequently fail to yield growth of common ocular pathogens or nonpathogenic bacteria. This prompts the following question: Is the ocular surface populated by a stable microbial population that cannot be detected using standard culture techniques? The study of the microbiome has recently become a widespread focus in physician and veterinary medicine. Research suggests a pivotal symbiotic relationship with these microbes to maintain healthy host tissues, and when altered is associated with various disease states ("dysbiosis"). The microbiota that lives within and on mammalian bodies have long been known to influence health and susceptibility to infection. However, limitations of traditional culture methods have resulted in an incomplete understanding of what many now call the "forgotten organ," that is, the microbiome. With the introduction of high-throughput sequencing, physician ophthalmology has recognized an ocular surface with much more diverse microbial communities than suspected based on traditional culture. This article reviews the salient features of the ocular surface microbiome and highlights important future applications following the advent of molecular techniques for microbial identification, including characterizing ocular surface microbiomes in our veterinary species and their potential role in management of infectious and inflammatory ocular diseases.

ClCPI, a cysteine protease inhibitor purified from Cassia leiandra seeds has antifungal activity against Candida tropicalis by inducing disruption of the cell surface.

Infections caused by Candida tropicalis have increased significantly worldwide in parallel with resistance to antifungal drugs. To overcome resistance novel drugs have to be discovered. The objective of this work was to purify and characterize a cysteine protease inhibitor from the seeds of the Amazon rainforest tree Cassia leiandra and test its inhibitory effect against C. tropicalis growth. The inhibitor, named ClCPI, was purified after ion exchange and affinity chromatography followed by ultrafiltration. ClCPI is composed of a single polypeptide chain and is not a glycoprotein. The molecular mass determined by SDS-PAGE in the absence or presence of β-mercaptoethanol and ESI-MS were 16.63 kDa and 18.362 kDa, respectively. ClCPI was stable in the pH range of 7.0-9.0 and thermostable up to 60 °C for 20 min. ClCPI inhibited cysteine proteases, but not trypsin, chymotrypsin neither alpha-amylase. Inhibition of papain was uncompetitive with a Ki of 4.1 × 10-7 M and IC50 of 8.5 × 10-7 M. ClCPI at 2.6 × 10-6 M reduced 50% C. tropicalis growth. ClCPI induced damages and morphological alterations in C. tropicalis cell surface, which led to death. These results suggest that ClCPI have great potential for the development of an antifungal drug against C. tropicalis.

Identification of zones with high potential for biological diversity on dormant forested landslides

Landslides and erosion processes cause a high level of morphological diversity which, over the course of time, results in an increased level of forest species and habitat biodiversity. According to the principles of landscape ecology, information concerning points of convergence—understood as transition zones between elementary parts of a slope—could be interpreted as a surrogate for biodiversity. To recognize locations of land surface disruption, points of convergence derived from a high-resolution digital elevation model (DEM) were used in the research. It was assumed that relationships exist between landslide geodiversity and biodiversity and that from the DEM it is possible to select bare-earth surface structures where points of convergence can be identified. In order to verify this hypothesis, indicators of biodiversity such as richness of plant species and species diversity were checked. Based on the spatial distribution of points of convergence, locations of sample plots were planned and these indicators were verified during fieldwork. Samples were taken both in areas with a high concentration of points of convergence and in areas with a low concentration (or absence) of points of convergence. The results show that species diversity in the areas having a high concentration of points of convergence was significantly higher than in the areas having a low concentration of points of convergence. The proposed method allows the selection of parts of forested landslides that have the potential to develop a high level of biological diversity; it thus supports the management of areas of forest ecosystems with high levels of biodiversity within the scope of a cutting system. This may entail avoiding the traversal of areas that potentially possess high biological diversity with skid roads, preserving parts of these areas with thick vegetation for forest game purposes or leaving predominant and dead trees. The proposed method may also be used in scientific research into processes of biodiversity appearing on forested landslides.

Mucopenetration and biocompatibility of polydopamine surfaces for delivery in an Ex Vivo porcine bladder

Urine voiding and the presence of a mucus layer on the apical surface of the urothelium are two major challenges towards an effective intravesical drug delivery for bladder malignancies. Improved bioavailability to the underlying bladder tissue could be achieved with delivery vectors that diffuse efficiently through the bladder mucus. Pegylation of delivery vectors remains the existing “gold standard” to enhance mucosal delivery despite known poor cell uptake and reported PEG sensitivity. Here, we showed improved mucopenetration of carboxylated polystyrene (PS) nanoparticles (NPs) passivated with a polydopamine (PDA) surface, at similar level as PEG. While the diffusion of PS NPs in mucus was retarded by ~1000-fold, PS-PDA diffused only 6-fold slower in mucus than water. This enabled faster and deeper penetration of PS-PDA into porcine bladder tissue beneath the mucus layer. The same PDA surface also conferred biocompatibility and enabled photothermal therapy (PTT) with significant surface disruption on an ex vivo porcine bladder model upon localized laser irradiation, which was not possible with PEG. Our outcomes suggested the facile and versatile PDA surface passivation of nanoparticles as an enabler for dual purposes of enhancing mucopenetration and allowing photothermal therapy on bladder tissue, which has not been demonstrated to date.

Yttrium ultra-thin films on the Si(100)2 × 1 surface and their in situ oxidation process

Yyttrium ultra-thin films (coverage <4 ML) and their interaction with oxygen on the Si(100)2 × 1 surface have been investigated in situ by Auger electron spectroscopy, low energy electron diffraction, thermal desorption spectroscopy, and relative work function measurements. The results show that yttrium develops in amorphous successive layers, interacting strongly with silicon at the interface, causing an early surface YSi intermixing and disruption of the silicon 2 × 1 symmetry. Yttrium increases drastically the oxygen sticking coefficient on silicon surface. It is surprising that even residual oxygen on the yttrium covered surface, induces a partial oxidation of silicon even at room temperature. By providing more oxygen, an Y-silicate compound (Y-O-Si) develops simultaneously with silica (SiO2) in a competitive way to each other. The silicate is thermally promoted by post-annealing process, probably due to the enhanced yttrium-silicon intermixing and/or inter-diffusion. Both of the silica and silicate are thermally stable compounds, which dissociate and desorb from the surface only at high temperatures (>1100 K). Desorbing species such as Y2Si and SiO were recorded and attributed to the cracking of silicate and silica respectively. A significant amount of yttrium always remains and/or diffuses into the silicon substrate, even after strong annealing. Such a procedure caused the appearance of a newly observed 3 × 1 phase corresponding to submonolayer yttrium coverage.

Teleost antimicrobial peptide hepcidin contributes to host defense of goldfish (Carassius auratus L.) against Trypanosoma carassii

Hepcidin is an antimicrobial peptide and an iron regulatory protein that prevents the release of excess iron in the blood. There is evidence suggesting that teleost hepcidin is a major player in antimicrobial defense against various bacteria species, but little is known regarding the effects of teleost hepcidin in protozoan parasitic infections. We examined the role of hepcidin during the course of infection of goldfish with Trypanosoma carassii. Quantitative real-time PCR was used to determine the expression of hepcidin in goldfish immune organs during the course of T. carassii infection. During the acute phase of the T. carassii infection, the mRNA levels of hepcidin were up-regulated in liver and kidney. In contrast, an up-regulation of hepcidin mRNA expression in spleen was observed during the chronic phase of the infection. Furthermore, a synthetic goldfish hepcidin peptide induced trypanosome lysis in vitro, and parasite surface disruption was confirmed by scanning electron microscopy (SEM) analysis. These results suggest that, in addition to well-characterized direct antibacterial activities, teleost hepcidin also exhibits trypanocidal activity.

Structure and water attachment rates of ice in the atmosphere: role of nitrogen.

In this work we perform computer simulations of the ice surface in order to elucidate the role of nitrogen in the crystal growth rates and crystal habits of snow in the atmosphere. In pure water vapor at temperatures typical of ice crystal formation in cirrus clouds, we find that basal and primary prismatic facets exhibit a layer of premelted ice, with thickness in the subnanometer range. For partial pressures of 1 bar, well above the expected values in the troposphere, we find that only small amounts of nitrogen are adsorbed. The adsorption takes place onto the premelted surface, and hardly any nitrogen dissolves within the premelting film. The premelting film thickness does not change either. We quantify the resulting change of the ice/vapor surface tension to be in the hundredth of mN m-1 and find that the structure of the pristine ice surface is not changed in a significant manner. We perform a trajectory analysis of colliding water molecules, and find that the attachment rates from direct ballistic collision are very close to unity irrespective of the nitrogen pressure. Nitrogen is however at sufficient density to deflect a fraction of trajectories with smaller distance than the mean free path. Our results show explicitly that the reported differences in growth rates measured in pure water vapor and a controlled nitrogen atmosphere are not related to a significant disruption of the ice surface due to nitrogen adsorption. On the contrary, we show clearly from our trajectory analysis that nitrogen slows down the crystal growth rates due to collisions between water molecules with bulk nitrogen gas. This clarifies the long standing controversy of the role of inert gases on crystal growth rates and demonstrates their influence is solely related to the diffusion limited flow of water vapor across the gas phase.

Micronization and extrusion processing on the physicochemical properties of dietary fiber

ABSTRACT: Dietary fiber plays an important physiological role, which is directly linked to its physicochemical properties, water-holding, oil-binding, and cation-exchange capacities. These properties can be altered by employing enzymatic, mechanical, and physical processes. Enzymatic and chemical processes require solvents and special conditions that make it unfeasible to use. Thus, the use of physical methods, such as micronization and extrusion, make promising options to change the physicochemical properties of dietary fiber. In this way, this review aimed to approach relevant information about the use of physical processes, specifically micronization and extrusion, for this purpose. Furthermore, conceptual aspects, such as definition, classification, and properties of dietary fiber and mainly characteristics about the micronization and extrusion processes, are reported. Micronization and extrusion are based on the decrease of the particle size to a micro scale and on the combination of high temperature, mechanical shearing and pressure, respectively. Applying these methods, modifications on the food matrix occurred by increasing the surface area and disruption of the glycosidic bonds. Consequently, there is a change in physicochemical properties of dietary fiber, which predict the physiological effect associated with dietary fiber consumption, such as decrease in blood cholesterol and glucose levels and improvement of intestinal transit. Moreover, these changes increase the bio accessibility of bioactive compounds present in the food matrix and improve the antioxidant capacity of products.

INFLUENCE OF SULFURIC ACID ATTACK ON CONCRETE WITH INDUSTRIAL WASTE

The paper aims at investigating cement composites with incorporated wastes such as blast granulated slag, fly ash, or micro silica regarding their durability and resistivity against aggressive acidic environments. An aggressive acidic attack was simulated with H2SO4 with a pH of 1.95. The experiments proceeded under model laboratory conditions over a period of 6 weeks, and the accelerated tank leaching test was applied. Both physical (mass of samples, water absorption, and surface disruption) and chemical parameters of concretes (pH, leachability of main components, chemical composition) were examined. The changes in the mass of samples, surface changes, as well as absorbability increases were observed after exposure to sulfuric attack. The leached-out amounts of calcium, silicon, aluminum, and iron, measured using X-ray fluorescence analysis, varied depending on the composition of the analyzed composite and the kind of waste incorporated. The samples with micro silica and slag were identified to be the most durable, regarding the leaching of basic inorganic compounds of the cement matrix. The sample with fly ash was observed to have the lowest change in water absorbability. The positive effect of incorporating waste into cement composite was confirmed when compared to a concrete sample without any waste added.

Thermodynamic Characterization of the Ca2+-Dependent Interaction Between SOUL and ALG-2.

SOUL, a heme-binding protein-2 (HEBP-2), interacts with apoptosis-linked gene 2 protein (ALG-2) in a Ca2+-dependent manner. To investigate the properties of the interaction of SOUL with ALG-2, we generated several mutants of SOUL and ALG-2 and analyzed the recombinant proteins using pulldown assay and isothermal titration calorimetry. The interaction between SOUL and ALG-2 (delta3-23ALG-2) was an exothermic reaction, with 1:1 stoichiometry and high affinity (Kd = 32.4 nM) in the presence of Ca2+. The heat capacity change (ΔCp) of the reaction showed a large negative value (−390 cal/K·mol), which suggested the burial of a significant nonpolar surface area or disruption of a hydrogen bond network that was induced by the interaction (or both). One-point mutation of SOUL Phe100 or ALG-2 Trp57 resulted in complete loss of heat change, supporting the essential roles of these residues for the interaction. Nevertheless, a truncated mutant of SOUL1-143 that deleted the domain required for the interaction with ALG-2 Trp57 still showed 1:1 binding to ALG-2 with an endothermic reaction. These results provide a better understanding of the target recognition mechanism and conformational change of SOUL in the interaction with ALG-2.

Reflectance increase from broad beam ion milling of coals and organic-rich shales due to increased surface flatness

Broad ion beam (BIB) milling is useful in organic petrology because it can yield flat sample surfaces and avert the ‘smearing’ of organic matter (OM) that results from traditional mechanical polishing. This potentially makes BIB especially useful in the study of nano-porosity, where even minor mechanical disruption of the sample surface distorts the sample characteristic of interest—the pore structure. However, several studies have observed an OM reflectance increase after BIB milling, concluding that ion milling may cause thermal alteration to OM surfaces. To better understand ion milling effects on organic matter, coal (subbituminous, high volatile bituminous, medium volatile bituminous, anthracite) and shale [Bakken Formation, Ohio Shale-Huron Member (5), Kimmeridge Clay Formation, Alum Shale, New Albany Shale] samples were prepared using traditional mechanical polishing methods. Reflectance measurements (% Ro) were gathered on all maceral types present before BIB milling, followed by re-measurement of OM reflectance at the same locations after milling. Most OM increased in reflectance after BIB milling, with some exceptions in high maturity samples. Liptinite macerals in both coal and shale samples showed the greatest percent reflectance increase on average (+133%; n = 338), followed by solid bitumen (+49%; n = 313), vitrinite (+26%; n = 413), and inertinite (+9%; n = 220). Despite the increases to OM reflectance caused by BIB milling, no evidence was found for kerogen conversion (e.g., change in maceral abundances), or for migration of newly generated petroleum (e.g., pseudomorphic replacement of kerogen by solid bitumen). Such changes occur when samples are thermally altered from immature conditions into the oil window (e.g., by hydrous pyrolysis), and, if the increases in OM reflectance were thermally driven (by BIB milling), they should have been observed in the above experiments. Herein, we also used atomic force microscopy to document a decrease in surface roughness of correlative locations of OM on pre- and post-ion milled samples. This improved surface polish caused by BIB milling appears to be the root cause of increased OM reflectance, as no other supporting evidence of thermal alteration could be found. That is, the fraction of light formerly lost to oblique scatter in diffuse reflectance from a mechanically polished surface is converted to specular reflectance after BIB ion milling. Thus the light leaves the surface at a near normal angle and returns to the detector, resulting in increased OM reflectance.

Enhancement of Methane Production from Banana Harvesting Residues: Optimization of Thermal–Alkaline Hydrogen Peroxide Pretreatment Process by Experimental Design

Increase of population has a significant effect on energy demand which results in depletion of fossil fuels, and this causes a search for alternative renewable energy sources. One of these alternatives is production of bioenergy and biofuel from renewable and non-food feedstocks such as lignocellulosic biomass and biowaste. However, lignocellulosic biomass needs pretreatment because of its complex structure. Effectiveness of thermal–alkaline H2O2 pretreatment process and determination of its optimum conditions using central composite design of RSM were evaluated for the enhancement of methane production from banana harvesting residues. Optimum process conditions for cost driven approach was determined as 50 °C reaction temperature, 2.73% H2O2 concentration and 6 h reaction time. As a result of pretreatment at optimum conditions, 40% increase on biochemical methane potential was obtained with 290 mLCH4/gVS methane production. SEM and FTIR results revealed surface disruption and lignin removal impacts of pretreatment, respectively. Thermal–alkaline H2O2 pretreatment was determined as an effective pretreatment process for banana harvesting residues.

The rationale behind surgical approaches to ankle fractures

Ankle fractures and fracture dislocations are one of the commonest injuries seen by orthopaedic surgeons. Decisions around the surgical fixation of ankle fractures require an understanding of the bony and ligamentous anatomy of the joint as well as an appreciation of the normal ankle joint biomechanics. The operative treatment of these injuries aims to hold the joint securely in an anatomically reduced position throughout the period of healing, and allow initiation of joint motion as soon as possible. If these treatment goals are met, a good outcome is a reasonable expectation, given the proviso that disruption of any articular surface can result in permanent damage. However the functional outcome of fractures involving a posterior malleolar fragment is often not satisfactory and recent debate has surrounded ankle fracture fixation, with the posterior malleolus in particular being subject to increased scrutiny for its contribution towards long-term ankle stability. With the advent of excellent results from the use of open reduction and rigid internal fixation, the gold standard of treatment for displaced ankle fractures has become surgical fixation. This article explores the evidence behind commonly used surgical approaches to ankle fracture fixation and the rationale behind their use.

Bacterial sensing: A putative amphipathic helix in RsiV is the switch for activating σV in response to lysozyme.

Extra Cytoplasmic Function (ECF) σ factors are a diverse group of alternate σ factors bacteria use to respond to changes in the environment. The Bacillus subtilis ECF σ factor σV responds to lysozyme. In the absence of lysozyme, σV is held inactive by the anti-σ factor, RsiV. In the presence of lysozyme RsiV is degraded via regulated intramembrane proteolysis, which results in the release of σV and thus activation of lysozyme resistance genes. Signal peptidase is required to initiate degradation of RsiV. Previous work indicated that RsiV only becomes sensitive to signal peptidase upon direct binding to lysozyme. We have identified a unique domain of RsiV that is responsible for protecting RsiV from cleavage by signal peptidase in the absence of lysozyme. We provide evidence that this domain contains putative amphipathic helices. Disruption of the hydrophobic surface of these helices by introducing positively charged residues results in constitutive cleavage of RsiV by signal peptidase and thus constitutive σV activation. We provide further evidence that this domain contains amphipathic helices using a membrane-impermeable reagent. Finally, we show that upon lysozyme binding to RsiV, the hydrophobic face of the amphipathic helix becomes accessible to a membrane-impermeable reagent. Thus, we propose the amphipathic helices protect RsiV from cleavage in the absence of lysozyme. Additionally, we propose the amphipathic helices rearrange to form a suitable signal peptidase substrate upon binding of RsiV to lysozyme leading to the activation of σV.

Tribological properties of high velocity suspension flame sprayed (HVSFS) ceramic coatings

Ceramic coatings were manufactured by high-velocity suspension flame spraying (HVSFS). Finely dispersed isopropanol-based suspensions with submicron- and nanoscaled Al2O3, 3-YSZ and TiO2 powders were used as feedstock material. Microhardness, surface, microstructure, and phase composition of the final coating were characterized. The tribological properties were investigated via ball-on-disc test in NaCl solution and compared to those of high velocity oxy liquid fuel (HVOLF) sprayed WC/Co coatings. The ceramic coatings exhibited material specific hardness. The high surface roughness of Al2O3, mainly composed of γ-phase, and TiO2, composed of anatase and rutile, could be explained by process inhomogeneities. While WC/Co was subjected to continuous wear due to abrasive processes and surface disruption, ceramic surfaces underwent a layer build-up, causing separation of the interacting surfaces and thus protection from increased wear. Considering tribochemical interactions between contacting materials and liquid medium, high chemical reactivity leads to high wear rates but moderate friction, whereas low reactivity results in low wear but high friction. Regarding potential application in pumps with SiC as standard material for sliding parts, 3-YSZ might be the most promising coating candidate due to moderate tribochemical interactions and therefore stable friction coefficients on a tolerable level and a similar wear rate compared with WC/Co.

Using a Microelectromechanical System to Identifying Roadway Surface Disruptions

The roadway surface disruptions (RSD) present several challenges for the drivers and governments agencies. The RSD affect the safety and comfort of the and reduce the useful life of the vehicle. To this end, it is necessary to develop systems capable to classify and inform about the locations and nature of RSDs. The availability of information about location of RSDs could lead to driving assisting technologies warning drivers of potential traveling disruptions. In this paper, the design of a instrumentation vehicle for the analysis and location of RSD is presented. The vehicle is equipped with several accelerometers, to measure the road imperfections, and a GPS to estimate de RSD locations. To analyze the accelerometer data, a filter FIR (Finite Impulse Response) a moving standard deviation is used. Finally, the RSD data are classified by a method based on threshold.