bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Leucine Supplementation on Exercise Training Induced Anti-Cardiac Remodeling Effect in Heart Failure Mice
Authors: De Moraes Wilson , Melara Thaís , De Souza Pamella , De Salvi Guimarães Fabiana , Bozi Luiz , Brum Patricia , Medeiros Alessandra
Published: May 2015

Leucine supplementation potentiates the effects of aerobic exercise training (AET) on skeletal muscle; however, its potential effects associated with AET on cardiac muscle have not been clarified yet. We tested whether leucine supplementation would potentiate the anti-cardiac remodeling effect of AET in a genetic model of sympathetic hyperactivity-induced heart failure in mice (α2A/α2CARKO). Mice were assigned to five groups: wild type mice treated with placebo and sedentary (WT, n = 11), α2A/α2CARKO treated with placebo and sedentary (KO, n = 9), α2A/α2CARKO treated with leucine and sedentary (KOL, n = 11), α2A/α2CARKO treated with placebo and AET (KOT, n = 12) or α2A/α2CARKO treated with leucine and AET (KOLT, n = 12). AET consisted of four weeks on a treadmill with 60 min sessions (six days/week, 60% of maximal speed) and administration by gavage of leucine (1.35 g/kg/day) or placebo (distilled water). The AET significantly improved exercise capacity, fractional shortening and re-established cardiomyocytes’ diameter and collagen fraction in KOT. Additionally, AET significantly prevented the proteasome hyperactivity, increased misfolded proteins and HSP27 expression. Isolated leucine supplementation displayed no effect on cardiac function and structure (KOL), however, when associated with AET (KOLT), it increased exercise tolerance to a higher degree than isolated AET (KOT) despite no additional effects on AET induced anti-cardiac remodeling. Our results provide evidence for the modest impact of leucine supplementation on cardiac structure and function in exercised heart failure mice. Leucine supplementation potentiated AET effects on exercise tolerance, which might be related to its recognized impact on skeletal muscle.
Hypolipidemic Effects and Safety of Lactobacillus Reuteri 263 in a Hamster Model of Hyperlipidemia
Authors: Huang Wen-Ching , Chen Yi-Ming , Kan Nai-Wen , Ho Chun-Sheng , Wei Li , Chan Ching-Hung , Huang Hui-Yu , Huang Chi-Chang
Published: May 2015

We aimed to verify the beneficial effects of probiotic strain Lactobacillus reuteri 263 (Lr263) on hypolipidemic action in hamsters with hyperlipidemia induced by a 0.2% cholesterol and 10% lard diet (i.e., high-cholesterol diet (HCD)). Male Golden Syrian hamsters were randomly divided into two groups: normal (n = 8), standard diet (control), and experimental (n = 32), a HCD. After a two-week induction followed by a six-week supplementation with Lr263, the 32 hyperlipidemic hamsters were divided into four groups (n = 8 per group) to receive vehicle or Lr263 by oral gavage at 2.1, 4.2, or 10.5 × 109 cells/kg/day for 6 weeks, designated the HCD, 1X, 2X and 5X groups, respectively. The efficacy and safety of Lr263 supplementation were evaluated by lipid profiles of serum, liver and feces and by clinical biochemistry and histopathology. HCD significantly increased serum levels of total cholesterol (TC), triacylglycerol (TG) cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C), LDL-C/HDL-C ratio, hepatic and fetal TC and TG levels, and degree of fatty liver as compared with controls. Lr263 supplementation dose dependently increased serum HDL-C level and decreased serum TC, TG, LDL-C levels, LDL-C/HDL-C ratio, hepatic TC and TG levels, and fecal TG level. In addition, Lr263 supplementation had few subchronic toxic effects. Lr263 could be a potential agent with a hypolipidemic pharmacological effect.
Oral Zinc Supplementation Reduces the Erythropoietin Responsiveness Index in Patients on Hemodialysis
Authors: Kobayashi Hiroki , Abe Masanori , Okada Kazuyoshi , Tei Ritsukou , Maruyama Noriaki , Kikuchi Fumito , Higuchi Terumi , Soma Masayoshi
Published: May 2015

Background: In hemodialysis (HD) patients, zinc depletion caused by inadequate intake, malabsorption, and removal by HD treatment leads to erythropoiesis-stimulating agent (ESA) hyporesponsiveness. This study investigated the effects of zinc supplementation in HD patients with zinc deficiency on changes in the erythropoietin responsiveness index (ERI). Methods: Patients on HD with low serum zinc levels (<65 μg/dL) were randomly assigned to two groups: The polaprezinc group (who received daily polaprezinc, containing 34 mg/day of zinc) (n = 35) and the control group (no supplementation) (n = 35) for 12 months. All the 70 patients had been taking epoetin alpha as treatment for renal anemia. ERI was measured with the following equation: Weekly ESA dose (units)/dry weight (kg)/hemoglobin (g/dL). Results: There were no significant changes in hemoglobin levels within groups or between the control and polaprezinc groups during the study period. Although reticulocyte counts were increased immediately after zinc supplementation, this change was transient. Serum zinc levels were significantly increased and serum copper levels were significantly decreased in the polaprezinc group after three months; this persisted throughout the study period. Although there was no significant change in the serum iron or transferrin saturation levels in the polaprezinc group during the study period, serum ferritin levels significantly decreased following polaprezinc treatment. Further, in the polaprezinc group, ESA dosage and ERI were significantly decreased at 10 months and nine months, respectively, as compared with the baseline value. Multiple stepwise regression analysis revealed that the change in the serum zinc level was an independent predictor of lowered ERI. Conclusions: Zinc supplementation reduces ERI in patients undergoing HD and may be a novel therapeutic strategy for patients with renal anemia and low serum zinc levels.
Tailoring Effective Media by Mie Resonances of Radially-Anisotropic Cylinders
Authors: Kettunen Henrik , Wallén Henrik , Sihvola Ari
Published: May 2015

This paper studies constructing advanced effective materials using arrays of circular radially-anisotropic (RA) cylinders. Homogenization of such cylinders is considered in an electrodynamic case based on Mie scattering theory. The homogenization procedure consists of two steps. First, we present an effectively isotropic model for individual cylinders, and second, we discuss the modeling of a lattice of RA cylinders. Radial anisotropy brings us extra parameters, which makes it possible to adjust the desired effective response for a fixed frequency. The analysis still remains simple enough, enabling a derivation of analytical design equations. The considered applications include generating artificial magnetism using all-dielectric cylinders, which is currently a very sought-after phenomenon in optical frequencies. We also study how negative refraction is achieved using magnetodielectric RA cylinders.
Segmentation-Based PolSAR Image Classification Using Visual Features: RHLBP and Color Features
Authors: Cheng Jian , Ji Yaqi , Liu Haijun
Published: May 2015

A segmentation-based fully-polarimetric synthetic aperture radar (PolSAR) image classification method that incorporates texture features and color features is designed and implemented. This method is based on the framework that conjunctively uses statistical region merging (SRM) for segmentation and support vector machine (SVM) for classification. In the segmentation step, we propose an improved local binary pattern (LBP) operator named the regional homogeneity local binary pattern (RHLBP) to guarantee the regional homogeneity in PolSAR images. In the classification step, the color features extracted from false color images are applied to improve the classification accuracy. The RHLBP operator and color features can provide discriminative information to separate those pixels and regions with similar polarimetric features, which are from different classes. Extensive experimental comparison results with conventional methods on L-band PolSAR data demonstrate the effectiveness of our proposed method for PolSAR image classification.
Towards Detection of Cutting in Hay Meadows by Using of NDVI and EVI Time Series
Authors: Halabuk Andrej , Mojses Matej , Halabuk Marek , David Stanislav
Published: May 2015

The main requirement for preserving European hay meadows in good condition is through prerequisite cut management. However, monitoring these practices on a larger scale is very difficult. Our study analyses the use of MODIS vegetation indices products, namely EVI and NDVI, to discriminate cut and uncut meadows in Slovakia. We tested the added value of simple transformations of raw data series (seasonal statistics, first difference series), compared EVI and NDVI, and analyzed optimal periods, the number of scenes and the effect of smoothing on classification performance. The first difference series transformation saw substantial improvement in classification results. The best case NDVI series classification yielded overall accuracy of 85% with balanced rates of producer’s and user’s accuracies for both classes. EVI yielded slightly lower values, though not significantly different, although user accuracy of cut meadows achieved only 67%. Optimal periods for discriminating cut and uncut meadows lay between 16 May and 4 August, meaning only seven consecutive images are enough to accurately detect cutting in hay meadows. More importantly, the 16-day compositing period seemed to be enough for detection of cutting, which would be the time span that might be hopefully achieved by upcoming on-board HR sensors (e.g., Sentinel-2).
The Elderly’s Independent Living in Smart Homes: A Characterization of Activities and Sensing Infrastructure Survey to Facilitate Services Development
Authors: Ni Qin , García Hernando Ana , De la Cruz Iván
Published: May 2015

Human activity detection within smart homes is one of the basis of unobtrusive wellness monitoring of a rapidly aging population in developed countries. Most works in this area use the concept of “activity” as the building block with which to construct applications such as healthcare monitoring or ambient assisted living. The process of identifying a specific activity encompasses the selection of the appropriate set of sensors, the correct preprocessing of their provided raw data and the learning/reasoning using this information. If the selection of the sensors and the data processing methods are wrongly performed, the whole activity detection process may fail, leading to the consequent failure of the whole application. Related to this, the main contributions of this review are the following: first, we propose a classification of the main activities considered in smart home scenarios which are targeted to older people’s independent living, as well as their characterization and formalized context representation; second, we perform a classification of sensors and data processing methods that are suitable for the detection of the aforementioned activities. Our aim is to help researchers and developers in these lower-level technical aspects that are nevertheless fundamental for the success of the complete application.
Determining the Leaf Emissivity of Three Crops by Infrared Thermometry
Authors: Chen Chiachung
Published: May 2015

Plant temperature can provide important physiological information for crop management. Non-contact measurement with an infrared thermometer is useful for detecting leaf temperatures. In this study, a novel technique was developed to measure leaf emissivity using an infrared thermometer with an infrared sensor and a thermocouple wire. The measured values were transformed into true temperatures by calibration equations to improve the measurement accuracy. The relationship between two kinds of measurement temperatures and setting emissivities was derived as a model for calculating of true emissivity. The emissivities of leaves of three crops were calculated by the mathematical equation developed in this study. The mean emissivities were 0.9809, 0.9783, 0.981 and 0.9848 for Phalaenopsis mature and new leaves and Paphiopedilum and Malabar chestnut leaves, respectively. Emissivity differed significantly between leaves of Malabar chestnut and the two orchids. The range of emissivities determined in this study was similar to that in the literature. The precision of the measurement is acceptable. The method developed in this study is a real-time, in situ technique and could be used for agricultural and forestry plants.
Intelligent Detection of Cracks in Metallic Surfaces Using a Waveguide Sensor Loaded with Metamaterial Elements
Authors: Ali Abdulbaset , Hu Bing , Ramahi Omar
Published: May 2015

This work presents a real life experiment of implementing an artificial intelligence model for detecting sub-millimeter cracks in metallic surfaces on a dataset obtained from a waveguide sensor loaded with metamaterial elements. Crack detection using microwave sensors is typically based on human observation of change in the sensor’s signal (pattern) depicted on a high-resolution screen of the test equipment. However, as demonstrated in this work, implementing artificial intelligence to classify cracked from non-cracked surfaces has appreciable impact in terms of sensing sensitivity, cost, and automation. Furthermore, applying artificial intelligence for post-processing data collected from microwave sensors is a cornerstone for handheld test equipment that can outperform rack equipment with large screens and sophisticated plotting features. The proposed method was tested on a metallic plate with different cracks and the obtained experimental results showed good crack classification accuracy rates.
Applying a Human-Centred Process to Re-Design Equipment and Work Environments
Authors: Horberry Tim , Burgess-Limerick Robin
Published: May 2015

Safe design is an increasingly influential approach due to a growing recognition of the contribution of design to workplace safety. It aims to eliminate workplace hazards by systematically involving end-users in the design or redesign process. In this review paper, the explicit and novel focus is upon redesign, rather than original design. The literature in the field is appraised and a human-centred safe redesign method is presented. The safe redesign method is a task-based, risk management approach that centres on end-users. In describing the method, indicative results from two domains are outlined: mining equipment and highway environments. Focusing on end-users and their tasks by means of a structured human-centred process can be highly beneficial. Further work to expand the human-centred safe redesign method is outlined.
Impact of multivalent charge presentation on peptide–nanoparticle aggregation
Authors: Schöne Daniel , Schade Boris , Böttcher Christoph , Koksch Beate
Published: May 2015

Strategies to achieve controlled nanoparticle aggregation have gained much interest, due to the versatility of such systems and their applications in materials science and medicine. In this article we demonstrate that coiled-coil peptide-induced aggregation based on electrostatic interactions is highly sensitive to the length of the peptide as well as the number of presented charges. The quaternary structure of the peptide was found to play an important role in aggregation kinetics. Furthermore, we show that the presence of peptide fibers leads to well-defined nanoparticle assembly on the surface of these macrostructures.
Mechanical stability of bivalent transition metal complexes analyzed by single-molecule force spectroscopy
Authors: Gensler Manuel , Eidamshaus Christian , Taszarek Maurice , Reissig Hans-Ulrich , Rabe Jürgen P
Published: May 2015

Multivalent biomolecular interactions allow for a balanced interplay of mechanical stability and malleability, and nature makes widely use of it. For instance, systems of similar thermal stability may have very different rupture forces. Thus it is of paramount interest to study and understand the mechanical properties of multivalent systems through well-characterized model systems. We analyzed the rupture behavior of three different bivalent pyridine coordination complexes with Cu2+ in aqueous environment by single-molecule force spectroscopy. Those complexes share the same supramolecular interaction leading to similar thermal off-rates in the range of 0.09 and 0.36 s−1, compared to 1.7 s−1 for the monovalent complex. On the other hand, the backbones exhibit different flexibility, and we determined a broad range of rupture lengths between 0.3 and 1.1 nm, with higher most-probable rupture forces for the stiffer backbones. Interestingly, the medium-flexible connection has the highest rupture forces, whereas the ligands with highest and lowest rigidity seem to be prone to consecutive bond rupture. The presented approach allows separating bond and backbone effects in multivalent model systems.
Magnetic Resonance Imaging in Hand Osteoarthritis: Intraobserver Reliability and Criterion Validity for Clinical and Structural Characteristics
Authors: Kortekaas Marion C. , Kwok Wing-Yee , Reijnierse Monique , Wolterbeek Ron , Bøyesen Pernille , van der Heijde Desiree , Bloem Johannes L. , Kloppenburg Margreet
Published: May 2015

Objective.

To investigate criterion validity and intraobserver reliability of magnetic resonance imaging (MRI) in hand osteoarthritis (HOA).

Methods.

In 16 patients with HOA (median age 57 yrs, 62% women, 13 with erosive OA), 3 Tesla MRI scans with gadolinium-chelate administration of right second to fifth distal interphalangeal/proximal interphalangeal joints were scored according to the Oslo HOA scoring method for synovial thickening, bone marrow lesions (BML), osteophytes, joint space narrowing (JSN), and erosions (grade 0–3). Ultrasound (US) was scored for synovial thickening and osteophytes, radiographs for osteophytes and JSN (Osteoarthritis Research Society International score), and anatomical phases (Verbruggen-Veys score). Pain was assessed during physical examination. Correlations of MRI with US and radiographic features were assessed with generalizability theory. With generalized estimating equations analyses, MRI features were associated with pain, adjusting for confounding.

Results.

Forty-three percent, 27%, 77%, and 61% of joints had synovial thickening (moderate/severe), BML, osteophytes, and erosions on MRI, respectively. Intraobserver reliability, assessed in 6 patients, was good (ICC 0.77–1.00). Correlations between osteophytes, JSN, and erosions on radiographs and MRI were moderate, substantial, and fair (ICC 0.53, 0.68, and 0.32, respectively); MRI showed more lesions than radiography. Correlation between synovial thickening and osteophytes on MRI and US was moderate (ICC 0.43 and 0.49, respectively). MRI was more sensitive for synovial thickening, US for osteophytes. Pain was associated with moderate/severe synovial thickening (adjusted OR 2.4, 95% CI 1.06–5.5), collateral ligaments (4.2, 2.2–8.3), BML (3.5, 1.6–7.7), erosions (4.5, 1.7–12.2), and osteophytes (2.4, 1.1–5.2).

Conclusion.

MRI is a reliable and valid method to assess inflammatory and structural features in HOA. It gives additional information over radiographs and US.
Low Temperature Synthesis of Yttrium-Stabilized Zirconia (YSZ) Fibers by Non-Hydrolytic Sol-Gel Method
Authors: Xin Ying , Jiang Wei Hui , Feng Guo , Liu Jian Min , Zhang Quan , Wu Qian , Miao Li Feng
Published: May 2015

Yttrium-stabilized zirconia fibers were prepared at low temperature via a novel non-hydrolytic sol-gel (NHSG) method by using anhydrous zirconium chloride as precursor, ethanol as oxygen donor, yttrium hydride as stabilizer, dibasic ester (DBE) as solvent, ethoxyline as spinning aid. DTA-TG, XRD, FT-IR, FE-SEM and TEM were used to characterize samples. The results show that the YSZ tetragonal zirconia can be synthesized at 410 °C and the formation of =Y-O-Zr≡ bond is the key for the low temperature synthesis tetragonal zirconia. Zirconia fibers calcined at 800 °C have a smooth surface, free of crack and dense section. The diameter of fibers are in the range of 5~10 μm. The addition of ethoxyline can make the colloidal particles linear growth which is the basic reason for the spinnability of the sol.
Study on the Preparation of BaTiO3 Nano Powder via Non-Hydrolytic Sol-Gel Method
Authors: Shao Zhi Peng , Jiang Wei Hui , Feng Guo , Liu Jian Min , Miao Li Feng , Zhang Quan , Wu Qian
Published: May 2015

BaTiO3 (BT) nano powder was prepared via non-hydrolytic sol-gel (NHSG) method by using barium acetate, titanium tetrabutoxide as precursors, glycerol and ethanol as solvents. The samples were characterized by DTA-TG, XRD, FT-IR and TEM. The influences of heat treatment temperature on the morphology and the microstructure of powder were studied, and the mechanism of low temperature synthesis was discussed. In addition, the de-esterification action between the precursors was also described in detail. The results show that the formation of Ba-O-Ti bond in the xerogel via NHSG route is duo to the de-esterification polycondensation of barium acetate and titanium tetrabutoxide, which plays the key role in the low temperature synthesis of BT powder. With the temperature rising to 700 °C, BT nano powder with good dispersion and even size distribution can be acquired and the average particle diameter is about 25 nm. Overlow and overhigh heat treatment temperatures are both not beneficial to the preparation of BT nano powder.
The Adsorption Properties of Ciprofloxacin by KMnO4 Modified Durio zibethinus Murr Shells
Authors: Shi Wei Mei , Ding Ye Chun , Wu Long Huo
Published: May 2015

Through the experiment of Ciprofloxacin (CIP) adsorption by KMnO4modifiedDurio zibethinusMurr Shell (KDS), the best condition, adsorption kinetics and thermodynamic characteristics were studied. The isotherm parameters were estimated by linear regression analysis with Langmuir isotherm model, Temkin isotherm and Freundlich isotherm model. The equilibrium process was described well by the Freundlich isotherm model, which indicated that the adsorption thermodynamics of CIP on KDS is a multilayer adsorption process．The kinetics of the interactions showed better agreement with the pseudo-second-order model (R2=0.9999). This study demonstrated that KDS could be used for the removal of CIP in water treatment.
Effects of Solvent on the Phase Composition and Microstructure of ZrSiO4 Film
Authors: Cao Fang , Chen Ting , Jiang Wei Hui , Liu Jian Min , Zha Jian Rui , Wu Qian
Published: May 2015

Zirconium silicate thin film was prepared via a novel non-hydrolytic sol-gel (NHSG) process at low temperature using zirconium tetrachloride (ZrCl4) and tetraethoxysilane (TEOS) as precursors. The phase composition and the microstructure of samples were characterized by X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM), respectively. The results demonstrate that pure ZrSiO4 film can be synthesized by using ethanol and isopropanol as solvent rather than dimethyl formamide (DMF) and dimethyl nylon acid (DBE) which cause impurity ZrO2. However, only ethanol can achieved smooth and dense ZrSiO4 film. The viscosity results suggest that the sol with ethanol has great stability. With a pulling rate of 1.0 mm s-1, a high quality ZrSiO4 film was prepared after drying at 50 oC for 2 h and calcination at 850 °C with a heating rate of 1.0 °C min-1.
Delamination of GFRP Panels in Bridge Decks
Authors: Stankiewicz Beata
Published: May 2015

Modern bridge structures need light decks with long durability and promising technical parameters. GFRP bridge deck creates possibilities in bridge designing. Parallel identification of GFRP deck panel: DTA analysis, spectroscopy analysis, scanning and optical microscope monitoring according to own investigation will be presented, in the paper. Modal, vibrations analysis is very important for bridge structures using light Glass Fiber Reinforced Polymer decks. The three 1stmodes and corresponding frequencies have been showed for chosen footbridges with GFRP ASSET system decks. The footbridges were excited by impact and human-induced vibrations. Good exploration of new material, like composite GFRP, generates potential to improve technology and make comparison analysis with traditional standard of materials. The dynamic behavior of damaged footbridge structures under moving loads has been studied. The paper is concerned with a micromechanical theory of macroscopic crack propagation due to stress-corrosion cracking in unidirectional glass-fiber-reinforced polymer composites, for bridge decks applications. The first form of damage in laminates is usually matrix micro cracks, which are intralaminar or ply cracks that traverse the thickness of the ply and run parallel to the fibers in that ply. The identification of early delamination process in footbridges GFRP deck is very important by them durability feature. Improving system for polymer resin using nanostructures is useful by aspect of reducing micro cracks and then macro cracks propagation.
Thermoluminescence Properties of Doped YAP Crystals
Authors: Yao Wen Wei
Published: May 2015

Many properties of thermodynamics and mechanics are similar between YAP crystal and YAG crystal. In this paper, TL properties of YAP:Nd, YAP:Er, YAP:Tm3+, YAP:Ho3+and YAP:Yb are introduced in the first place. The TL spectral lines and dose response curves of the YAP:Mn, YAP:Cu and YAP:Ce are analyzed in some detail. It has been found that the doped YAP crystal may function as an excellent dosimeter material of radiation owing to its unique properties.
Retarding Bioactivity Effect of Ciprofloxacin Incorporated in Polyvinyl Alcohol/Bioglass Scaffold as Bone Graft
Authors: Boulila Salha , Oudadesse Hassane , Lefeuvre Bertrand , Chaabouni Khansa , Makni-Ayedi Fatima , Pellen Pascal , El Feki Hafedh , Barroug Allal , El Feki Abdelfattah
Published: May 2015

The biomaterials are used for many biomedical applications. The main objective of the present work was to investigate the potential role of Bioglass (Melting)- Polyvinyl alcohol (BG (M)-PVA) and Bioglass (Melting)-Polyvinyl alcohol-20%Ciprofloxacin (BG (M)-PVA-20Cip) in regenerative bone capacity. These composites were implanted in the femoral condyles of Wistar rats and compared to that of ovariectomised groups. Our results noted, after the different period of implantation (15, 30, 60 and 90 days), that the Alkaline phosphatase (ALP) and Acid phosphatase (ACP) activities showed an excellent osteoinductive property of BG (M)-PVA, that this phenomena decreased with the presence of ciprofloxacin. Physico-chemical techniques (ICP-OES and SEM) were engaged to highlight the influence of antibiotic on the structure, porosity and bioactivity of a porous Glass-PVA before and after implantation. The results obtained by ICP-OES showed a rapid reduction in silicon (Si) and sodium (Na), and noted an accelerator increase in calcium (Ca) and phosphorus (P) ion concentrations in BG (M)-PVA that the BG (M)-PVA-20Cip. This result is confirmed by SEM. We can conclude that the loading of ciprofloxacin in BG (M)-PVA is characterized by a retard effect of formation of apatitic phase.
Interface Reaction between Nd2O3 and Alumina Single Crystal
Authors: Bi Si Long , Wu Bo Lin , Wu Yang
Published: May 2015

A kind of high alumina content ceramic stand wear and tear has been designed. The interface chemical reaction between single crystal alumina (in order to eliminate the influence of grain boundaries) and Nd2O3 powder has been observed. Microstructure and wear rate of the ceramic were investigated by SEM and by a purposely designed experimental device for the measurement of wear rate. Perimental results showed that a rare earth aluminate formed on the interface and the wear rate of a sample has reduced by 34%. The newly formed compound and single crystal alumina formed a compact structure which could make the grain boundaries strengthened and also lead to a beneficial effect on the elimination of pore and the density of the ceramic, at the same time improve abrasive resistance.
Mechanism Research of Pr6O11 Addition on Wear Resistance of Alumina Ceramics
Authors: Wu Yang , Wu Bo Lin , Bi Si Long
Published: May 2015

Many literatures reported rare earth ions would segregate at grain boundaries toinhibit grain growth and improve the ceramic performance. However, the mutualinfluence between segregation and alumina grains was rarely seen in thereports. In this article, interface reaction between single crystal alumina (inorder to eliminate the influence of grain boundaries) and praseodymium oxidewas designed to further understand the influence mechanism. The resultssuggested that a composite oxide was formed at the junctions. Besides, largestresses produced between the composite oxide and alumina because of the thermalexpansion coefficient difference. This stresses would weaken grain boundariesbonding strength and reduce wear resistance.
Preparation of α-Al2O3 Powders via Non-Hydrolytic Sol-Gel Method
Authors: Zhou Tong Qing , Chen Ting , Jiang Wei Hui , Liu Jian Min , Zhang Xiao Jun , Miao Li Feng
Published: May 2015

Corundum structurealumina (α-Al2O3) powders were prepared via a non-hydrolytic sol-gel (NHSG) method using aluminum as raw material, ethanol as solvent, and iodine as catalyst. X-ray diffraction (XRD), differential thermal analysis (DTA), thermo gravimetric analysis (TG) were used to characterize the crystal phase of the products, while scanning electron microscopy (SEM) and transmission electron microscope (TEM) were employed to analyze the morphology. The results indicated that γ-Al2O3 was completely changed to α-Al2O3 at 1100 o C with a bit of aggregation. When 3 wt.% polyethylene glycol 600 (PEG 600) was introduced on the NHSG process, the dispersion was improved and the particle size decreased to100 nm.
Optimal Conditions for Bio-Oxidation of Biodesulfurization in Natural Gas Sweetening Process Using Thiobacillus
Authors: Liu Qi Song , Xu Bo , He Jin Long , Sun Ru , Chang Hong Gang
Published: May 2015

Hydrogen sulfide is a common composition of natural gas. It is an important problem to develop suitable natural gas desulfurization technology for the present situation of China. Now, a novel process of H2S abatement from gas streams has been investigated for chemical absorption of H2S using a weak alkaline solution followed by the oxidation of the absorbed sulfide to elemental sulfur by naturally occurring microorganisms and alkaline solution regeneration for recycle and reuse in the process. This method is currently attracting more and more interests of researchers, because it requires little equipment, is inexpensive and produces only elemental sulfur, thus minimizing the production of pollutants. The biological oxidation process of the absorbed sulfides to elemental sulfur by Thiobacillus thioparus TYY-1 was studied in an airlift-loop reactor (effective volume=20L).Two efficiency factors including hydraulic remain time and the air aeration quantity were inspected. The air aeration quantity is key influence factor of desulfuration rate and elemental sulfur production rate. The investigation demonstrated that the optimum hydraulic remain time was 4—6h under the influent concentration of S2- for 200 mg/L, and the best treatment effect of aeration was obtained at 120 —160L/h. With these conditions after 20 days of operation, the result showed superior performance of the bioreactor for desulfuration rate and elemental sulfur production rate, the conversion products were mainly sulfur and the production rate of SO42- was low. The removal efficiency of sulfide was more than 99.5% while the maximum yield of sulfur was 88% approximately.
Sensitivity Analysis of the Wall Shear Model to the Correlations for Frequency and Slug Holdup in the Gas-Liquid Slug Flow in Pipes
Authors: Melo Lima Luiz Eduardo , Rosa Eugênio Spanó
Published: May 2015

The one-dimensional mixture model efficiently predicts gas-liquid flows dominated by gravity force. The advantages of the mixture model are the absence of interfacial terms and the reduced number of transport equations, but its weakness lies on the constitutive laws to predict the wall shear force of a gas-liquid mixture. The objective of this work is to realize a sensitivity analysis of the wall shear model (based on the intermittent behavior of the gas and liquid structures) to the correlations for frequency and slug holdup in the one-dimensional, steady state mixture model applied to an isothermal gas-liquid mixture flowing in the slug regime. The numerical results for the pressure gradient obtained here are compared against experimental data from previous work.
Study of Defluidization Region of Large Particles in Fluidized Bed Using the Gaussian Spectral Pressure Distribution
Authors: Silveira Flavia Tramontin , Janzen Frederic Conrad , Parise Maria Regina
Published: May 2015

The present work aimed to identify the defluidization region of a gas-solid fluidized bed system composed by Geldart group D particles using the Gaussian spectral pressure distribution technique, which is based on pressure fluctuation measurements in the plenum. In experiments, the defluidization condition of glass beads with apparent density of 2,450 kg/m3 was induced in a plexiglas column of 0.11 m in inner diameter and 1.0 m in height. The gas-solid behavior close to the incipient fluidization condition was assessed for two fixed bed heights (0.10 and 0.20 m) and two mean sizes of particles (1.55 and 2.18 mm in diameter). The bed was fluidized with air at environment temperature. The experimental equipment was instrumented with a pressure transmitter connected to a data acquisition system in order to record the pressure fluctuations of the gas-solid flow. The results showed that the defluidization region can be detected efficiently by using the Gaussian spectral pressure distribution technique, which contributes for a better control of fluidized bed processes.
Statistical Evaluation of Bioleaching of Mobile Phone and Computer Waste PCBs: A Comparative Study
Authors: Arshadi Mahdokht , Mousavi Seyyed Mohamad
Published: May 2015

Mobile phone PCBs (MPPCBs) is one of the most important targets in e-waste from both economical and environmental threat points attention to their high dense composition of metals. Because of the inhibitory effect of metals especially copper on gold recovery, for gold extraction from MPPCBs a successive two stage bioleaching using Acidithiobacillus ferrooxidans and Bacillus megaterium, was applied. At the first stage, it was tried to extract copper and nickel from the waste. Then using B. megaterium the gold extraction from MPPCBs was examined. The amount of gold which extracted was about 64 g/ton while the average amount of gold in a mine in the world is about 8-10 g/ton. For both of stages the optimum condition was determined using response surface methodology.
The Study on the Property and the Microstructure of Pressureless Sintered h-BN Ceramics
Authors: Gao Xiao Ju , Yan Dong Ming , Cao Jian Wu , Zhang Cong , Mu Xiao Ming , Zhou Ya Wei , Wang Meng , Qu Fa Zeng , Li Guo Bin , Wang Guo Jiang , Zhang Da Jiang
Published: May 2015

Hexagonal boron nitride ceramic（h-BN）has been prepared by pressureless sintering method. The effect of sintering aids, moulding pressure and sintering temperature on the mechanical properties and microstructures of h-BN were investigated. The results show that the densification of as-prepared h-BN ceramic can be contributed to the addition of sintering-aids and the formation of card-house structure. Because of the high densification and card-house microstructure, the obtained h-BN demonstrates higher bending strength and lower porosity when the moulding pressure is 200MPa, sintering temperature is 1850°C and the contents of sintering aids is 10wt%.
Analysis of Changes in the Surface Quality of a UD Prepregs Composite due to Mechanical Loading
Authors: Petrů Michal , Syrovátková Martina , Martinec Tomáš , Lepšík Petr
Published: May 2015

Optimizing the mechanical properties of composites is very important for light low energy constructions. Unidirectional prepreg (UD prepreg) is an intermediate product synthesizing a unidirectional layer of carbon fibres with a matrix. This can be used in the production of continuous fibres of reinforced composites. The individual layers can be stacked on top of each other to precisely orientate the layers and attain the maximum properties in a given direction. The resulting composite is ultra thin with the highest possible fraction of fibres. Prepreg composites are very high quality and have very good mechanical properties. They can be applied in sectors where the requirements for mechanical resistance are very high. This paper presents an experimental and numerical analysis of the surface of a composite and the changes that may occur to it under the influence of loading. The Ball Drop Test (ASTM D6024-07 / DIN 52306) was used as a stress test. Test samples scanned by image analysis showed that the surface properties of the UD prepreg were not disrupted, while scanning with AXIO IMAGER M2 showed apparent surface disruptions. From the numerical simulations it was determined that a directional orientation of the fibres of +45°/0°/-45° significantly affects their elastic properties.
X-Ray Diffraction Analysis of Zn-Mg Coating in Dependence on Deformation
Authors: Zuzánek Lukáš , Ridky Ondrej , Solfronk Pavel , Kolnerová Michaela , Sobotka Jiří , Ganev Nikolaj
Published: May 2015

The Zn-Mg coatings are considered as the next generation of steel covering to be used in automotive industry since they improve the corrosion resistance of the base material. The article is focused on the X-ray diffraction analysis of Zn-Mg coating in dependence on strain. The specimens made from a material, which has Zn-Mg coating, were gradually deformed until they became totally fractured. Subsequently, the specimens´ surface layer was analysed using X-ray diffraction. X-ray diffraction methods are used for evaluation of the qualitative changes in the real structure of the polycrystalline material. The modification of the real structure is considered as a degree of plastic deformation, change of crystallite size and their orientation depending on deformation.
Corrosion of Dry - Bottom Boiler Evaporator in Power Industry
Authors: Maršál Robert , Podjuklová Jitka , Siostrzonek René , Pavelková Daniela , Koldová Lenka , Pěnička Zdeněk
Published: May 2015

This contribution solves the character of corrosive damage of the tubes, steam generating tubes of dry-bottom boiler combustion chamber in power plant engineering, and deals with the aspects related to the corrosion criteria of the carbon steel. The laboratory test results of samples applied on tubes that were subject to non-destructive and destructive tests are analyzed in one part of the work. The samples of greater incidence of corrosion products, which caused the failure of the integrity of the steam generating tubes, were tested. The work deals in details with the results of laboratory and chemical analysis of boiler water from the previous periods. The thesis evaluates the amount and frequency of P2O5 dosing cycles. The work also deals with the proposal of corrective measures that shall lead to the chemical balance of the boiler water. It proposes a continuous correlation methodology for chemical stabilization.
Some Possibilities of Evaluation of Corrosive Resistance of Metal and Non-Metal Coatings
Authors: Hagarová Mária , Fečková Zuzana , Lacková Petra , Cervová Jana
Published: May 2015

The study investigated the possibilities of determination of corrosion resistance of metal and non-metal (organic) coatings deposited to steel surface in the corrosion environment. To determine the corrosion rate of metal PVD coating based on Ti, we used the method involving measurement of polarization conductivity. Corrosion resistance of galvanic Ni or Ni-Co coatings was determined by measuring free corrosion potential ESCE (against that of saturated calomel electrode SCE), or by means of potentiodynamic polarization relationships according to Tafel. These methods provided the basic corrosion characteristics: corrosion potential Ecorr, instantaneous corrosion rate jcorr and polarization resistance Rp. Corrosion resistance of organic coating Woerodur, which was applied by pressure spray to the substrate pre-treated in various ways, was tested in a salt-fog environment. After the exposure to the respective environment we evaluated the appearance of coating. The aim of the study was to point out to the availability of methods suitable for evaluation of corrosion resistance of coatings, and to the possibilities of their application under real practical conditions.
Evaluation of Corrosion Resistance of Galvanized Steel Sheets Used in Automotive Production
Authors: Kaščák Luboš , Brezinová Janette , Mucha Jacek
Published: May 2015

The steel sheets used for the car body production are protected against corrosion by zinc coating. Resistance spot welding is used mainly for joining these sheets, because of its high speed and adaptability for automation in high-rate production. However, resistance spot welding has a negative influence on the corrosion resistance of joints. The paper focuses on the analysis of quality of welds on galvanized steel sheets and their corrosive properties. Tensile test and accelerated corrosion test in corrosive environment were used for evaluation of the welds’ quality. Protective efficiency of zinc coatings for automobile sheets was evaluated as well, based on the determination of their electrochemical characteristics in passivated and non-passivated state, as well as their corrosion resistance in simulated corrosion environments. Two types of DX54D+Z material were used for experiments: non-passivated and passivated with Cr3+.
Impact of Cathodic Protection on Selected Polymeric Coatings
Authors: Lovíšek Martin , Liptáková Tatiana , Dundeková Sylvia , Šimko Pavol
Published: May 2015

The cathodic protection is used in combination with organic coatings to protect steel constructions in soil and water environment, when their long lifetime and safety are expected. The parameters of the cathodic protection must be respected very strictly because the exceeded protective potential can evoke degradation of polymeric coatings and delamination. Our paper comprises the results of experiments those determine the impact of various applied protective potential on degradation of the selected polymeric coatings. The specimens were prepared of sheet steel 425310.11. Prior to the application of organic coatings, one set of specimens was treated by blasting (classic method) the second set by laser. The behavior of the physically (based on polyisobutene PIB) and chemically cured (based on polyurethane PU) coatings were studied after one year lasting exposure in the soil. The experiment was carried out by exposure of specimens in soil without and with cathodic protection of different intensity.
The Influence of Substrate Surface Cleanliness on the Corrosion Resistance of Coating Systems
Authors: Hanák Miroslav , Podjuklová Jitka , Siostrzonek René , Pavelková Daniela , Koldová Lenka
Published: May 2015

Water-based coating systems are becoming increasingly popular among consumers due to their simple application and a wide range of colours. A common mistake made by users of these coating systems is neglecting of diagnostics of the corrosive environment and failing to eliminate the factors that cause corrosion aggressiveness. On the boundary of two different environments there can be corrosion products developed and dust particles deposited, which may cause, under certain circumstances, development of deeply hidden corrosion, and thus reduce the level of protection of the substrate. In order to provide long-term protection of the substrate the coating system must be able to eliminate the corrosion agents effectively. In addition to the requirements for aesthetic value set by the consumers, also environmental aspects must be taken into account in the long-term protection of the substrate.
Morphological Changes on Spruce Wood Surface, Induced by Treatment with Dry Ice
Authors: Kúdela Jozef , Mrenica Leoš , Čunderlík Igor , Šmíra Pavel
Published: May 2015

This work concerns the changes to wood surface morphology induced by surface cleaning with dry ice. The surface roughness values demonstrated that the surface treatment with dry ice resulted in amplified surface roughness, mainly due to the increase in the roughness of early wood. The treatment of old wood with dry ice not only guarantees effective removal of contamination from the wood surface, it also induces positive changes in other (such as wettability, surface free energy, color, and similar). This way of wood surface treatment guarantees more wood surface quality for the surface treatment, impregnation or gluing.
The Sodium Water Glass in Surface Treatment of Chordophones
Authors: Danihelová Anna , Ružinská Eva , Spišiak Dominik
Published: May 2015

The article deals with the use of sodium water glass in production of top plate of chordophones and its influence on the physical and acoustic characteristics of wood (density – ρ, modulus of elasticity – E, acoustic constant – A, speed of sound – c) as well as on the frequency spectrum. The selected characteristics of resonance spruce wood (Picea abies), were measured via non-destructive dynamic method on the apparatus called MEARFA. Measurement showed that sodium water glass influences the required characteristics (ρ, A, c) of spruce wood negatively. The frequency analysis was carried out by means of FFT (Fast Fourier Transform).
Photostability of Transparent Surface Coatings of Wood
Authors: Slabejová Gabriela , Vidholdová Zuzana
Published: May 2015

The paper deals with the evaluation of photostability of six selected transparent surface coatings applied on veneered furniture parts. It also estimates the influence factors such as exposure to natural sunlight in the interior, the length of exposure, wood species of used veneers and type of transparent coatings. The changing colour of surface treatment was evaluated on samples stored in the interior and being exposed to natural light behind the window glass for 6 months. Significant changes were occurred on surfaces treated with transparent coatings without UV absorber. During the first three months of exposure were arisen the most colour changes in transparent coatings of veneers.
Tribological Research of Properties of Heat – Treated Cast Irons with Globular Graphite
Authors: Bronček Jozef , Fabian Peter , Radek Norbert
Published: May 2015

The contribution deals with the evaluation of tribological properties of materials: isothermally heat-treated cast iron ADI, heat-treated cast iron with globular graphite HTDI with sorbitic structure of the basic metal matrix and heat-treated steel C45. The aim of the research is to gain another knowledge for the application of materials in the condition where the loss of mechanical energy and the loss of material caused by parts wear are being appeared.
Quality Analysis of Welding Joints on Helically Welded Pipes
Authors: Gatial Martin , Viňáš Ján , Poľak Jaroslav
Published: May 2015

This material presents the results of the quality evaluation of the weld joints on helically welded pipes, diameter DN 800 mm, made of HSLA steel X 70 (L 485 MB EN 10208-2) with a wall thickness of 11mm. The pipes designed for transportation of natural gas were submerged arc welded by method 121 EN ISO 4063. The filler material used was welding wire OK Autrod 12.24, and the basic flux S A AB 1 67 AC H5 EN ISO 14 174 in two grain-size ranges (0.2-0.8 mm) and (0.8-1.6 mm). The quality of the weld joints was evaluated using a visual inspection, radiation inspection, static tensile test, impact strength tests, macroscopic and microscopic analysis of the weld joints using the light microscopy. The analysis confirmed only minimal differences in the quality of weld joints in favor of the joints welded by the filler with 0.8-1.6 mm grain-size.