Changes In Surface Characteristics Research Articles

Topographic and Chemical Analysis of Reciprocating and Rotary Instruments Surface after Continuous Use.

This study aimed at evaluating the changes in surface characteristics and NiTi content of reciprocating and rotary instruments after continuous use. Thirty brand-new instruments were assigned to 3 groups (n=10): PNX1 Group - ProTaper Next system - instrument X1; PNX2 Group - ProTaper Next system - instrument X2 and WO Group - WaveOne system - Primary instrument 25.08. The instruments were used to prepare 60 simulated root canals. Analysis of surface characteristics by scanning electron microscopy (SEM) and chemical analysis of Ni and Ti content by energy-dispersive spectroscopy (EDS) were performed before and after the first and third use of the instruments. Only WO Group had significant increase in the quantity of defects and deformations after the third use (p<0.05). PNX1 Group had significant decrease in Ni content after the third use, in comparison with the unused instruments (p<0.05). PNX1 Group had no decrease in Ti content throughout the time of use (p>0.05), however, in PNX2 Group, there was significant decrease in the different time interval of analysis (p<0.05). Continuous use promoted increase in defects and deformations only for WaveOne instruments. Chemical composition presented significant changes according to the time of instruments use.

Assessing the impact of changes in surface cover, human behaviour and climate on energy partitioning across Greater London

Climate-sensitive urban design is an increasingly important consideration for city planners and policy makers. This study demonstrates the use of a biophysical model to assess the response of urban climate to various changes, including population growth, reduced energy use, urban development and urban greening initiatives. Model inputs are intentionally derived using only publicly available information and assumptions involved in collating the data are discussed. Results are summarised in terms of the energy partitioning which captures changes in meteorology, surface characteristics and human behaviour. The model has been recently evaluated for the region, and those findings are drawn upon here to discuss the model’s capabilities and limitations. Model simulations demonstrate how both intentional and inadvertent changes to the urban landscape can alter the urban climate. For example, the impact of population growth depends on where, and how, people are housed, and recent changes in garden composition have reduced evaporation. This study has been designed so that model output could be combined with socio-economic data in future, enabling both risk and vulnerability to be considered together.

Transport of E. coli in saturated and unsaturated porous media: effect of physiological state and substrate availability

Saturated and unsaturated sand and soil column experiments were conducted to study the complex interaction between the effects of biological and hydrological factors on the transport of bacteria through a porous medium. These experiments were conducted with continuous input of bacteria and substrate at the inlet to reflect the groundwater contamination caused by leaking septic tanks and leach pits. Experiments were conducted with metabolically active and inactive Escherichia coli. Cell surface characteristics and batch experimental data for bacterial attachment were correlated with the transport behaviour in continuous column studies. Normalized breakthrough concentration for metabolically inactive cells (C/C 0 = 0.74 in sand) was higher than that for active cells (C/C 0 = 0.68 in sand) owing to change in cell surface characteristics. A similar trend was observed in the case of transport through soil columns. There was an increase of 29.5% in the peak C/C 0 value at the outlet when the flow velocity was increased from 0.0535 cm/h (C/C 0 = 0.61) to 0.214 cm/h (C/C 0 = 0.79) in case of sand columns. However, this difference was only 20% in case of soil columns. Peak normalized concentrations at the outlet were less in soil column as compared to those in sand column because of lesser grain size. Unlike the earlier studies with pulse input, present experiments with continuous input of metabolically active bacteria along with substrate indicated that the normalized concentration at the outlet increased with increased concentration at the inlet. It was found that unsaturated conditions led to more retention of bacteria in both sand and soil columns. In case of sand columns, the normalized concentration at the exit reduced to as much as 0.46. It was also found that the existing mathematical models based on macroscopic advection–dispersion–filtration equations could satisfactorily simulate the bacterial transport except in a case where the substrate was added to the bacteria in the column studies.

Quantifying Changes in Surface Characteristics of Concrete due to Progressive Deterioration

AbstractScaling, erosion, and cracking are some manifestations of deterioration of concrete surfaces due to chemical attack, exposure to cyclic freezing and thawing, and so forth. Though a rating o...

Rhamnolipid-aided biodegradation of carbendazim by Rhodococcus sp. D-1: Characteristics, products, and phytotoxicity

We successfully isolated Rhodococcus sp. D-1, an efficient carbendazim-degrading bacterium that degraded 98.20% carbendazim (200ppm) within 5days. Carbendazim was first processed into 2-aminobenzimidazole, converted to 2-hydroxybenzimidazole, and then further mineralized by subsequent processing. After genomic analysis, we hypothesized that D-1 may express a new kind of enzyme capable of hydrolyzing carbendazim. In addition, the effect of the biodegradable biosurfactant rhamnolipid on the rate and extent of carbendazim degradation was assessed in batch analyses. Notably, rhamnolipid affected carbendazim biodegradation in a concentration-dependent manner with maximum biodegradation efficiency at 50ppm (at the critical micelle concentration, CMC) (97.33% degradation within 2days), whereas 150ppm (3 CMC) rhamnolipid inhibited initial degradation (0.01%, 99.26% degradation within 2 and 5days, respectively). Both carbendazim emulsification and favorable changes in cell surface characteristics likely facilitated its direct uptake and subsequent biodegradation. Moreover, rhamnolipid facilitated carbendazim detoxification. Collectively, these results offer preliminary guidelines for the biological removal of carbendazim from the environment.

Effects of layer-by-layer assembled PEI/MWCNT surfaces on enhanced pool boiling critical heat flux

Layer-by-layer (LbL) assembly is a versatile deposition technique for the fabrication of nanostructured thin films on a substrate. In this study, multilayers of poly(ethylenimine) (PEI) and multi-walled carbon nanotubes (MWCNTs) were deposited onto a stainless steel surface. Since a substrate experiences notable changes in surface characteristics and structures during the LbL deposition process, resulting surface characteristics were thoroughly investigated. It was found that randomly oriented porous structures were developed by the fibrous wires of MWCNTs. As a result, surface roughness increased by 20–30%, and surface wettability increased by 70% for all samples. Both roughness and wettability were improved as the bilayer number increased. After the surface modification process, pool boiling heat transfer experiments were conducted to investigate the thermal margin achievable with the LbL deposition. Critical heat flux (CHF) enhancement was obtained as the number of bilayers increased, with the maximum enhancement evaluated at 94%. The enhancement was mainly attributed to the improved surface characteristics due to the formation of porous structures in the PEI/MWCNT layer. The comparison works with newly proposed CHF correlations supported the wicking effect on the CHF enhancements for the LbL-assembled test samples. Image processing results indicated a desirable structure for improved capillary action, which could affect further wetting to dry spots. High-speed bubble departure images were obtained from which a few msec reduction in rewetting intervals was observed for all LbL-assembled heaters.

Monitoring the variations of evapotranspiration due to land use/cover change in a semiarid shrubland

Abstract. Evapotranspiration (ET) is an important process in the hydrological cycle, and vegetation change is a primary factor that affects ET. In this study, we analyzed the annual and inter-annual characteristics of ET using continuous observation data from eddy covariance (EC) measurement over 4 years (1 July 2011 to 30 June 2015) in a semiarid shrubland of Mu Us Sandy Land, China. The Normalized Difference Vegetation Index (NDVI) was demonstrated as the predominant factor that influences the seasonal variations in ET. Additionally, during the land degradation and vegetation rehabilitation processes, ET and normalized ET both increased due to the integrated effects of the changes in vegetation type, topography, and soil surface characteristics. This study could improve our understanding of the effects of land use/cover change on ET in the fragile ecosystem of semiarid regions and provide a scientific reference for the sustainable management of regional land and water resources.

Digital reconstruction of the Song Dynasty Ganzhou drainage system based on AR technology and its’ application in the new urban area planning and revision

Water-logging problem is a common problem in modern city. The urban built-up area of Zhangjiang new district in Ganzhou has the same water-logging problem, however, the old urban area of Ganzhou was praised as “Millennium no flood”. The drainage system of the old urban area of Ganzhou—Fushougou, which is not flooded for hundreds years because of the perfect drainage system. It’s valuable to be referenced to the modern city drainage and waterproof comprehensive planning. In order to explore the mystery of “Millennium no flood” of old urban area of Ganzhou, at the same time to provide directive opinion to the sustainability of Zhangjiang new urban area drainage system, this paper attempts to digital reconstruct the drainage system in old urban area of Ganzhou by augmented reality(AR). It will provide a new technological means and ways to evaluate the sustainability of urban underground drainage system under the surface feature changes in the landscape. On the basis of digital reconstruction of the drainage system in the old urban area of Ganzhou, the sustainability evaluation index of drainage system is studied by analyzing and contrasting with Zhangjiang new urban area drainage system, to guide the revision of comprehensive planning about city drainage and water-logging in the new urban area of Zhangjiang.

The effect of amino functionalized and polyethylene glycol grafted nanodiamond on anti-biofouling properties of cellulose acetate membrane in membrane bioreactor systems

Abstract In this work, cellulose acetate (CA) nanocomposite membranes were prepared by embedding amino functionalized nanodiamond (ND-NH 2 ) as well as polyethylene glycol grafted ND (ND-PEG); 0–0.75 wt.%, in order to improve the membrane surface hydrophilicity and subsequently reduce membrane biofouling in the membrane bioreactor (MBR) system. Scanning electron microscopy (SEM) and contact angle measurements were used to determine the surface properties of the membranes. To compare the prepared nanocomposite membranes with pure CA membrane, critical flux, fouling behavior, and anti-fouling properties against extracellular polymeric substances (EPS) were studied. The Fourier transform infrared (FT-IR) spectra analysis showed that the NH 2 functional groups and PEG molecule formed on the surface of ND. Maximum improvement in hydrophilicity properties of CA membrane was observed at 0.5 wt.% loading of ND-PEG. Also, higher critical flux and anti-fouling properties was obtained by CA/ND-PEG (0.5 wt.%) nanocomposite membrane due to the change in surface characteristics. Analysis of extractable EPS showed that the concentrations of proteins and carbohydrates in the EPS and soluble microbial products (SMP) for CA/ND-NH 2 (0.5 wt.%) and CA/ND-PEG (0.5 wt.%) membrane are less than that of other membranes. Meanwhile, COD removal for all of the membranes was higher than 90%, whereas only 83.4% removal efficiency was achieved in the activated sludge.

Biocompatible Hermetic Encapsulation for Implantable Miniaturized Biomedical Sensor System

The field of medical engineering with high standards for implantable applications requires frequently not only sensitive measuring systems but also long term stability and less inflammatory reactions after implantation. Implantable electronics relies on a hermetic and dissolvent consistent encapsulation. Already used materials, such as parylene C, have excellent barrier properties, protect from corrosion and show good bio-stability. But, the biocompatibility of such materials is often insufficient. The in this work described encapsulation with a special coating of polyethylene glycolated amino acids could improve this. The better cell compatibility as well as the protein repellent behaviour and the changes in surface characteristics implies that this coating enhances the functionality and biocompatibility in general. This encapsulation is of current interest for an implantable blood glucose measuring system based on the piezoresistive pressure sensor chip containing a glucose-sensitive hydrogel in its cavity.

The Effects of Carbon and Gold Ion Implanted Surfaces on Neuronal Stem Cells’ Functions

Biomaterials have been used in medicine for decades to improve the functions of tissues and organs. They are also used as prosthesis and implants which are designed to substitute functions of a lacking organ or tissue. Carbon (C) and Gold (Au) were particularly chosen due to their biocompatibility and applied as implants for decades. Carbon and gold were great ion sources for medical applications, as well. In this study, polystyrene dishes were modified using gold and carbon ions via ion implantation technique. Using this surface modification method, it was aimed to improve surface characteristics and achieve a bioactive surface for neural stem cells. Even though the integration of stem cells was promising, neural stem cell studies still have many milestones to reach. Neuro-regeneration was the most desired function for people who suffer from neural system diseases. Changing surface characteristics of scaffolds was a way to promote regeneration and ion implantation was one of the methods to modify surface properties which play a huge role in enhancing the proliferation and integration of cells. In this study, it was observed that the ion implantation stimulated the neural proliferation and the implantation of different ions on cell culture surfaces was essential to determine the effects of this technique on adhesion, proliferation, differentiation and apoptosis properties of cells in details.

Damage and deuterium retention of re-solidified tungsten following vertical displacement event-like heat load

Surface morphology and hydrogen isotope retention of W specimen melted with vertical displacement event-like heat load and subsequent deuterium (D) plasma exposure were studied. Applied heat loads using electron beam without raster scanning were about 190 and 230 MW/m2 in heat flux and 0.08, 0.12 and 0.16s in duration. After the heat load application, specimens showed apparent melting spots with grain growth or dense micrometer scale convex structure. Cracks were observed only in the part with the convex structure. D retention in the melted part of specimens was not significantly larger than in the reference specimen despite large changes of surface characteristics.

Ultra-violet Protection and Easy- care Children Garments by Nanotechnology

This research focuses on nanotechnology in finishing of cotton/polyester fabrics. Treatment of cotton / polyester fabrics 75/25% were done by using Arcofix as anti-crease agent and ZnO (Zinc oxide) nanoparticle as UV protection agent in children garments (middle childhood) 6-9 years. The used fabrics have the following specifications: Three weaves structures (plain 1/1- twill 2/2- stain 5) with weft density (16-24-28) picks/cm. The fabrics were treated with Arcofix, 80g/l and ZnO nanoparticle at different concentrations (0.001-0.002-0.003)g/l then curing at 150°C for three minutes, some investigations, such as ( meter square weight – crease recovery angle –tear strength- UPF) were done for treated and untreated fabrics. Scanning electron microscope (SEM) was used to detect the changes in surface characteristics, the obtained results found that the best weave structure for all performance properties was the stain5 with the pick 28pick/ cm which treated by ZnO nanoparticle 0.003g/l , quality factor (94.16)% ,while the plain 1/1with 16 pick/cm was the least by a quality factor (50.55)% . The fabrics with stain 5 design structure used for design of five shirts for middle childhood (6-9) years . The statistics showed that the fifth design is the best design for all proposed designs . Aims of research: Ultra-violet protection and easy-care in children clothes by nanotechnology. Achievement of optimum conditions for weave structure, number of picks and concentration of ZnO nanoparticles. Make some shirts designs suggested to children from the best treatment fabrics and choose the best one. Results: The impact of study factors on the functional properties of the fabrics produced under research . Analysis of variance (ANOVA) has been made to study the impact of study factors (weave structure, numbers of picks, ZnO nanoparticles concentration) of the fabrics produced under research.Hence the importance of this research to shed light on the reciprocal relationship between the mother and her female child and the extent of the Girls' link and attachment to their mothers, through innovate fabric designs of ladies clothes and their formats for the children.We cannot ignore the world fashion trends and the importance of guide with it to make a printing product with an Egyptian identity and at the same time fits the latest fashion trends in taste, color, shape and quality. And on the other side, and in technological terms, the product has to be environmentally friendly and safe to the young consumer (children).

Time-dependent effects of ultraviolet and nonthermal atmospheric pressure plasma on the biological activity of titanium

Here, we evaluated time-dependent changes in the effects of ultraviolet (UV) and nonthermal atmospheric pressure plasma (NTAPPJ) on the biological activity of titanium compared with that of untreated titanium. Grade IV machined surface titanium discs (12-mm diameter) were used immediately and stored up to 28 days after 15-min UV or 10-min NTAPPJ treatment. Changes of surface characteristics over time were evaluated using scanning electron microscopy, surface profiling, contact angle analysis, X-ray photoelectron spectroscopy, and surface zeta-potential. Changes in biological activity over time were as determined by analysing bovine serum albumin adsorption, MC3T3-E1 early adhesion and morphometry, and alkaline phosphatase (ALP) activity between groups. We found no differences in the effects of treatment on titanium between UV or NTAPPJ over time; both treatments resulted in changes from negatively charged hydrophobic (bioinert) to positively charged hydrophilic (bioactive) surfaces, allowing enhancement of albumin adsorption, osteoblastic cell attachment, and cytoskeleton development. Although this effect may not be prolonged for promotion of cell adhesion until 4 weeks, the effects were sufficient to maintain ALP activity after 7 days of incubation. This positive effect of UV and NTAPPJ treatment can enhance the biological activity of titanium over time.

Climatic consequences of adopting drought‐tolerant vegetation over Los Angeles as a response to California drought

AbstractDuring 2012–2014, drought in California resulted in policies to reduce water consumption. One measure pursued was replacing lawns with landscapes that minimize water consumption, such as drought‐tolerant vegetation. If implemented at broad scale, this strategy would result in reductions in irrigation and changes in land surface characteristics. In this study, we employ a modified regional climate model to assess the climatic consequences of adopting drought‐tolerant vegetation over the Los Angeles metropolitan area. Transforming lawns to drought‐tolerant vegetation resulted in daytime warming of up to 1.9°C, largely due to decreases in irrigation that shifted surface energy partitioning toward higher sensible and lower latent heat flux. During nighttime, however, adopting drought‐tolerant vegetation caused mean cooling of 3.2°C, due to changes in soil thermodynamic properties and heat exchange dynamics between the surface and subsurface. Our results show that nocturnal cooling effects, which are larger in magnitude and of great importance for public health during heat events, could counterbalance the daytime warming attributed to the studied water conservation strategy. A more aggressive implementation, assuming all urban vegetation was replaced with drought‐tolerant vegetation, resulted in an average daytime cooling of 0.2°C, largely due to strengthened sea breeze patterns, highlighting the important role of land surface roughness in this coastal megacity.

Effects of sodium hypochlorite on structural/surface characteristics, filtration performance and fouling behaviors of PVDF membranes

Sodium hypochlorite (NaClO) is a common chemical cleaning agent in water treatment due to its effective removal of irreversible pollutants that cannot be removed by physical cleaning. In this research, PVDF ultrafiltration (UF) membranes were exposed to NaClO for 120–960h, and then the structural/surface characteristics of the control and exposed membranes were compared. Results showed that different exposure doses lead to variations in PVDF membrane structural/surface characteristics according to different mechanisms and further influence the permeability and fouling behaviors of PVDF membranes during ultrafiltration (UF) processes. Reversible fouling was the most common fouling behavior of membranes and exposure to NaClO resulted in higher degree of irreversible fouling. The irreversible flux decline of the membranes could not only caused by physically irremovable fouling but also irreversible compaction of the membranes due to the formation of macro-voids in the membrane skin layer. The changes in membrane mechanical properties caused a sharp increase in the inherent membrane resistance (Rm) which was generally considered as a constant. ‘Dynamic resistance mechanism’ could be proposed based on the impact of different NaClO exposure doses on the total membrane resistance (Rt ), which is the sum of the changes in Rm and the variation of fouling resistance (Rf) resulted from the changes in surface characteristics of the membranes. According to this concept, the filtration operating conditions and cleaning processes could be optimized in water treatment.

Overall Changes in Surface Characteristics after Diamond Grinding Continuously Reinforced Concrete Pavement

AbstractThe paper presents the results of a case study to quantify the deterioration of a diamond-ground continuously reinforced concrete pavement (CRCP) surface in terms of macrotexture, skid resistance, ride quality, and pavement noise over time. The influence of site-specific features such as traffic speed and load, pretexturing prior to the grinding operation, lane, wheel path, and trafficking direction on the deterioration of the surface properties is considered. The four surface properties were measured before and immediately after the grinding operation and at three subsequent time intervals after 4, 9, and 15 months. Panel data analysis incorporating fixed effects was implemented to evaluate the influence of the site-specific features on the deterioration of the surface properties. The study provides statistical evidence of deterioration. A significant reduction in macrotexture and skid resistance was apparent. An increase in noise was evident soon after grinding. No significant change in roughnes...

Feed-direction ultrasonic vibration−assisted milling surface texture formation

ABSTRACTThe formation mechanism of surface texture for feed-direction ultrasonic vibration−assisted milling (UVAM) was investigated in this study by establishing a kinematic model and a pressing model of UVAM. The kinematic model showed that the cutter tip, which was supposed to be totally sharp, produced closed scratches by crossed trajectories. The variation trends of the interval for closed textures were of sine function. A comparative experiment was carried out by UVAM and conventional milling. A dividing line close to the X coordinate divides the surface feature into two parts. The pressing model showed that the tool minor cutting edge left clear traces with certain width because of the tool minor cutting edge angle. Scratches by tool minor cutting edge were intermittent and regularly varied when feed-direction vibration was introduced. All the surface feature changes are in the radial direction and the trajectory intersections shall always be the scratch grooves or ridges. The ratio between ultrasonic vibration frequency and spindle speed, tool radius, and the located cutter rotation angle affected the changing rule of scratches by tool minor cutting edge. The analytical models and the experimental results proved to each other reasonable.

Changes of exoskeleton surface roughness and expression of crucial participation genes for chitin formation and digestion in the mud crab (Macrophthalmus japonicus) following the antifouling biocide irgarol

Irgarol is a common antifoulant present in coastal sediment. The mud crab Macrophthalmus japonicus is one of the most abundant of the macrobenthos in the costal environment, and its exoskeleton has a protective function against various environmental threats. We evaluated the effects of irgarol toxicity on the exoskeleton of M. japonicus, which is the outer layer facing the environment. We analyzed transcriptional expression of exoskeleton, molting, and proteolysis-related genes in the gill and hepatopancreas of these exposed M. japonicus. In addition, changes in survival and exoskeleton surface characteristics were investigated. In the hepatopancreas, mRNA expression of chitinase 1 (Mj-chi1), chitinase 4 (Mj-chi4), and chitinase 5 (Mj-chi5) increased in M. japonicus exposed to all concentrations of irgarol. Mj-chi1 and Mj-chi4 expressions from 1 to 10μgL−1 were dose- and time-dependent. Ecdysteroid receptor (Mj-EcR), trypsin (Mj-Tryp), and serine proteinase (Mj-SP) in the hepatopancreas were upregulated in response to different exposure levels of irgarol at day 1, 4, or 7. In contrast, gill Mj-chi5, Mj-Tryp, and Mj-SP exhibited late upregulated responses to 10μgL−1 irgarol compared to the control at day 7. Mj-chi1 showed early upregulation upon exposure to 10μgL−1 irgarol and Mj-chi4 showed no changes in transcription in the gill. Gill Mj-EcR presented generally downregulated expression patterns. In addition, decreased survival and change of exoskeleton surface roughness were observed in M. japonicus exposed to the three concentrations of irgarol. These results suggest that exposure to irgarol induces changes in the exoskeleton, molting, and proteolysis metabolism of M. japonicus.

Dissolution Enhancement of Domperidone Fast Disintegrating Tablet Using Modified Locust Bean Gum by Solid Dispersion Technique

Enhancement of dissolution characteristics of poorly soluble drug Domperidone by solid dispersion technique using modified locust bean gum (MLBG) and further conversion into tablet dosage form with fast dissolving characteristics is being explored in current study. Solid dispersions (SD) were prepared by solvent evaporation technique. F1, F3, F5 and F7 batches of SD (1:1, 1:3, 1:5 and 1:7 ratio of drug to MLBG) were prepared. Maximum solubility was observed in 1:3 ratio (F3 batch) in comparison to pure drug. Fourier Transform Infrared spectroscopy studies revealed no interaction of drug to polymer MLBG. Transition from crystalline to amorphous state of drug was analyzed by X-RD studies. SEM studies revealed change in surface characteristics of drug in solid dispersions. In vitro release studies revealed maximum dissolution in F3 (93% in 30 min). Further solid dispersion batches F3 was compressed into tablets including other excipients and crosspovidone as superdisintegrant. The in vitro release from tablet batch revealed better dissolution characteristics (95% in 30 min) in comparison to marketed tablet (50% in 60 min). Therefore, MLBG solid dispersion tablets of domperidone can be a convenient dosage form with enhanced dissolution characteristics.