bluuebunny/crossref_metadata_2025 huggingface dataset:
Tribological Properties of Ni-Cr-W Matrix High Temperature Self-Lubrication Composites Sintered by Hot Isostatic Pressing
Authors: Sun Jian Rong , Li Chang Sheng , Tang Hua , Liu Jin Yinzi , Guo Zhi Cheng
Published: December 2012

The high temperature self-lubrication Ni-Cr-W matrix composites were prepared by powder metallurgy and sintered by hot isostatic pressing (HIP). Atomized Ni-Cr-W powder was mixed with friction components of MoS2and Graphite. The mixed powders were cold pressed 450MPa and sintered at 1100°C~1200°C in the presence of argon atmosphere for 1 hour under 180MPa hot isostatic pressing with respect to their application in slide bearing bushing. The tribological properties are investigated on UMT-2 tester in ball-on-disc against alloy steel ball. The results showed that the appropriate addition of MoS2show excellent antifriction and wear resistance. And the friction coefficients and wear rates decrease over the wide temperature range of 25°C~600°C compared that of the composites by pressureless sintered method. The results indicated that HIP technology had an obviously strengthening effect on the density, and anti-press strength.
Experimental Study of Tensile Test of Line Fittings Steel under Low Temperature
Authors: Yin Quan
Published: December 2012

The main mechanical properties of line fitting steel under low temperature is different from that under normal temperature．the experiments of line fitting steel(Q345R)under low temperature and the Variation of the mechanical properties (yielding strength、ultimate strength、elongation)with temperature is showed in the paper．
Study on the Performance and Process of Materials for Special Gas Cylinder
Authors: Ren Shan , Yu Chang Chun
Published: December 2012

The explosion suppression fire extinguisher is an important component part of fire extinguishing and explosion suppression system of special equipment. Because of particularity and specificity of the place where it is used, the explosion suppression fire extinguisher’s body itself is commonly called the special gas cylinder. The material for special gas cylinder selected and used in the earliest design is mainly the ordinary steel gas cylinders such as the carbon structural steel gas cylinder. Because of the following characteristics: being rich in their resources, the prices are low and the process is simple, they can meet the requirements for the use in many kinds of places, and up to now, there are still used widely. But with the continuous development of special equipment in the fields of land, seas and oceans, aviation and aerospace and so on, the single material for the ordinary steel gas cylinder is unable to meet the special requirements of some special equipment. Therefore, it is necessary to research and manufacture new materials whose performance is different from the performance of steel gas cylinder and replace steel gas cylinder with the new materials, in order to meet the different demand in every field. With the continuous development of materials science of our country, some new materials and new technologies are researched and applied continuously. To design the rational manufacturing process by analyzing and researching the performance and technology of these new materials can meet the new requirements of new type of special equipment for explosion suppression fire extinguisher and improve the protective ability of special equipment.
Temperature Monitoring System Research of Hoist Brake Shoe
Authors: Sha Yong Dong , Hou Jing
Published: December 2012

In order to effectively protect hoist brake shoe′s braking performance, improve the work reliability and service life, establishing temperature monitoring system of hoist brake shoe in braking process.This system consists of detection system and alarm, communication lines, host computer, etc., can be for hoist brake shoe online measurement temperature and real-time monitoring, with low energy consumption, small size, reliability and stability, information processing ability and other characteristics.The system for staff to provide effective reference data, can be according to the monitoring results related parameters in the fixed, ensure brake shoe under the premise of performance improved the safety and reliability of the brake system.
An Experimental Study of the Thermal Properties of Modified 9Cr-1Mo Steel
Authors: Sivabharathy M. , Palanichamy P. , Vasudevan M. , Kalyanasundaram P. , Ramachandran K.
Published: December 2012

In this paper, the application of the photo-acoustic method to study the thermal properties of modified 9Cr-1Mo Steel is described. The photo-acoustic measurements are carried out for the thermal properties of modified 9Cr-1Mo steel samples of various thicknesses. The theoretical basis for quantitative measurements is discussed, together with the advantages and limitations of these methods as compared with conventional measurements.
Defect and Dislocation Density Parameters of 5251 Al Alloy Using Positron Annihilation Lifetime Technique
Authors: Abdel-Rahman M.A. , Elsayed M. , Attallah Ahmed G. , Ibrahim A.A. , Badawi Emad A.
Published: December 2012

The result of positron lifetime measurements of a defected 5251 Al alloy is reported. Positron lifetime is measured as a function of the thickness reduction of the sample which shows a nearly linear increase and then becomes constant; which can be considered to be a reason for the defect movement saturation. The trapping rate, trapping efficiency, trapping cross-section, defect concentration and defect density of positrons are also measured for the sample concerned. The behaviors of these parameters are matched with theoretical calculations. Data are analyzed using the PATFIT88 computer program.
A Novel Computational Strategy to Enhance the Ability of Elaborate Search by Entire Swarm to Find the Best Solution in Optimization of AMCs
Authors: Shabani Mohsen Ostad , Mazahery Ali
Published: December 2012

Al 6061 alloy matrix reinforced with the coated B4C particles have been used to investigate the accuracy of a novel optimization method. Population-based optimization was inspired by the swarming behavior as is displayed by a social behavior being influenced by other individuals. The present article focuses on a method of re-evaluating a number of randomly chosen sentry particles to detect the change of environments. A comprehensive population-based optimization method was developed to optimize the mechanical and tribological properties in metal matrix composites using Multi-strategy ensemble particle swarm optimization. In this method, the particles are divided into two parts which are considered to play different roles in searching for dynamic environments by using different strategies. The global best used in part one is the best solution found by all particles, both in part one and part two.
Comparative Investigations of the Sandfishs β-Keratin (Reptilia: Scincidae: Scincus scincus). Part 2: Glycan-Based Friction Reduction
Authors: Staudt Konrad , Böhme Wolfgang , Baumgartner Werner
Published: December 2012

The sandfish (Scincidae: Scincus scincus) is a lizard having outstanding skin properties. The scales show low friction behaviour and high abrasion resistance. After giving molecular support by DNA and protein analysis in Part 1 for increased glycosylation of the skins β-keratins, in this study the effect of glycans for friction reduction was investigated by (1) ammonium-based keratinolysis of skin exuviae and applying a β-keratin film on a glass surface and by (2) β-elimination based deglycosylation of β-keratins and immobilization of liberated glycans on a glass surface via silanisation. Both techniques resemble the natural model in the species investigated, the sandfish Scincus scincus and the Berber skink Eumeces schneideri. In the sandfish, a decreased friction coefficient was found by friction angle measurements, and a low adhesion force was measured by investigation with atomic force microscopy (AFM). These characteristics are possibly based by prevention of the formation of van der Waals bonds. This low adhesion force correlates with low friction and has a positive impact on abrasion resistance. A monosaccharide analysis confirmed the presence of carbohydrates.
Effect of γ-Radiation on Thermal and Chemical Properties of Starch/Polystyrene Biopolymer Blend
Authors: Ahmed Jaheel K. , Abdul Amer Zuhair J. , Majid Ahmed
Published: December 2012

In this study, the starch/polystyrene (PS) biopolymer blend is prepared by utilizing an in solution polymerization process. Two different ratios (50/50 and 80/20) of starch/PS were dissolved in toluene associated with mechanical mixing to maintain the homogeneity of the blend. Thereafter, the blend was exposed to γ-radiation using Cobalt 60 (Co60) at different dosing rates. The thermal and chemical properties were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), enzymatic degradation, and disclosure of starch by iodine, respectively. The deviation of glass transition temperature (Tg ( and the IR peaks indicate that a good interaction between starch and polystyrene was achieved in the blend. Exposure of the starch/PS blend to the α-amylase enzyme and to iodine demonstrated that the γ-rays have affected the amylopectin part with no distinct effect on the amylose part of the starch. Moreover, the colour has completely disappeared at 100 kGray irradiation dose since the blend becomes more responsive to enzymatic degradation at higher irradiation dose, which in turn causes in breaking down of the amylose part in the starch.
Bacterial Biofilm Development on Polyethylene with Organic and Inorganic Reagents In Vitro
Authors: Li Hong Mei , Li Huan Xin , Zhao Wei Guo , Zhang Wei , Ji Jun Hui
Published: December 2012

The antimicrobial efficacy of polyethylene (PE) with organic antibacterial agent and inorganic antibacterial agent were evaluated in this work. Moreover, inhibition to bacterial biofilm on their surfaces was investigated in detail. Our experimental results showed that both modified PE samples exhibited excellent antimicrobial performances against S. aureus and E. coli with low cell suspension. When cell suspension increased up to109 cell/ml, a large amount of bacteria (S. aureus and E. coli) and extracellular polysaccharide matrix adhered to the untreated PE and PE with inorganic antibacterial agent. On the other hand, adhesion, colonization and biofilm of S. aureus did not occur on PE with organic antibacterial agent, and a little E. coli survived on its surface. It was demonstrated that organic antibacterial agent had better ability to inhibit bacteria propagation than the inorganic one in initial time, and thus it prevented adherent bacteria to develop biofilm on the surface. The difference was derived from different initial effect time of them against bacteria. Therefore, it was a better approach to prevent catheter-related infections through addition of organic reagent into bulk material.
Constraints to the Growth of Small Scale Fabrication Industry in Nigeria – A Case Study of Benin Metropolis
Authors: Igbinomwanhia D.I. , Abuya E.G.
Published: December 2012

The small-scale fabrication industry is of great importance to developing an economy. In the last two decades governments and private agencies in Nigeria have demonstrated great concerns in developing the Small Scale Industries through policy formulation and support for agencies created with a view to developing the industry. But such concerns have not yielded any good results. There are therefore some salient problems bedeviling this sector. The work presented in this paper is a study of the constraints to the growth of the small scale fabrication industry in Nigeria using Benin metropolis as a case study. Structured questionnaires were used to collect primary data and interviews were also conducted. The data collected were then analyzed and the constraints to the growth of the industry were identified. The results obtained from the study showed that non awareness of government policies; inadequate technology, inadequate educational training and lack of finance are the major constraints to the development of the small scale design and fabrication industry in Nigeria. Recommendations are made for overcoming these constraints.
A New Theoretical Method for Transport Processes in Nanosensoristics
Authors: di Sia Paolo
Published: December 2012

The approach for converting nanoscale mechanical energy into electrical energy using piezoelectric nanowire arrays has been shown by a deflection of the nanowires via a corrugated electrode operated up and down by ultrasounds. I have performed an analytical method for describing the most important quantities concerning transport phenomena; it predicts very high initial diffusion of charge. This behaviour appears via mechanical external device stresses, which assumes therefore the typical characteristics of a nanosensor. With this method it is possible to deduce interesting informations about the device sensitivity, focusing on the important correlation between sensitivity and high initial diffusivity of these materials at nanometric state.
Synthesis of Nanoflower Precursors in Two-Phase System via Microwave-Assisted Hydrothermal Method and their In Situ Thermal Convention to NiO
Authors: Zhang Yan Bin , Zhu Zhen Feng , Zhang Wen Jia , Zhang Yan Li , Liu Hui , Chen Guan Hong , Wang Yu
Published: December 2012

The novel nanoflower precursors were successfully fabricated via microwave hydrothermal process in the presence of an anion surfactant Poly (N-vinyl-2-pyrrolidone). Nickel oxide (NiO) with the similar morphology of precursors was also obtained by a simple thermal decomposition of the as-prepared precursors at 400 °C for 2 h in air. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. The synthesized NiO nanoclusters have a cubic structure with an average size 500-1000 nm. The specific capacitance of NiO is about 208.4 F/g.
Biogenic Silver Nanoparticles: Antibacterial and Cytotoxicity Applied to Textile Fabrics
Authors: Marcato Priscyla D. , Nakasato Gerson , Brocchi Marcelo , Melo Patricia S. , Huber Stephany C. , Ferreira Iasmin R. , Alves Oswaldo L. , Durán Nelson
Published: December 2012

The silver nanoparticles production (~8 nm) byFusarium oxysporumwas evidenced by the presence of the plasmon absorption band. These particles were stable by several months due to protein capping originated by the biogenic process as observed by transmission electron microscopy (TEM). The cytotoxicity of silver nanoparticles was assayed on V79 fibroblast cell line and were evaluated by tetrazolium reduction and neutral red uptake giving an IC50of 22 μM. Silver nanoparticles impregnation in textile fabrics was made through the padding method and their impregnation was confirmed by SEM-EDS. The antimicrobial tests on the textile fabric were done with different bacteria. These fabrics showed antimicrobial activity against all the studied bacteria. The antimicrobial activity was maintained until the 30ª washes showing the high adhesion of these nanoparticles on the fabric fibers probably due to interaction between protein capping and fibers. Then, it was demonstrated an efficient method of stable silver nanoparticles production and their high adhesion on the textile fabrics.
Beauty and battle: How the Spirit is moving and operating in the Reformed Churches of the Netherlands
Authors: Kommers J. Hans
Published: December 2012

This article discusses how we in the present day hear the sound of the Holy Spirit and where his work can be witnessed in the Reformed Churches of the Netherlands. Mainstream churches have been faced with many challenges during the first decade of the 21st century. Many people have left these churches and have had little contact with its institutions. Is it necessary for them to search for spirituality elsewhere? The author is convinced that the Lord is not bypassing his church. The following question is relevant, In what way is the Spirit working today? This question is urgent, because today there is a renewed search for the reality and power of the Holy Spirit. Within the great and traditional Reformed Churches we hope to see a spiritual renewal. Last year the synod of the Protestant Church in the Netherlands revealed a new vision for mission work, which indicates that the church wants to return to its core function, to reach out to others who do not know the Lord Jesus Christ. Looking forward to the dynamic work of the Holy Spirit in this century, we are already witnessing the beauty of the work of the Holy Spirit, but we have a battle to wage in order not to lose what has been gained.Grootsheid en stryd: Die dinamiese werking van die Gees in die Gereformeerde Kerke van Nederland. In hierdie artikel word die teenwoordigheid en werking van die Heilige Gees in die Gereformeerde Kerke van Nederland bespreek. Die hoofstroomkerke het met baie uitdagings te kampe gehad tydens die eerste dekade van die 21ste eeu. Baie mense het hierdie kerke verlaat sonder om enige verdere interne kontak daarmee te hê. Was dit vir hulle nodig om elders na spiritualiteit te gaan soek? Die outeur is daarvan oortuig dat die Here nie sy kerk verlaat het nie. Die volgende vraag is relevant: Op watter wyse werk die Gees vandag? Hierdie vraag is belangrik, aangesien daar ‘n hernude soeke is na die wese  en krag van die Heilige Gees. Binne die groot tradisionele gereformeerde kerke hoop en verwag ‘n mens om  spirituele herlewing te sien. Die sleutelplan wat die Protestantse Kerk van Nederland (PKN) se sinode in 2009 bekendgestel het vir die oplewing in sending, wys dat die kerk wil terugkeer na sy kerntaak. ‘n Toekomsblik op  die dinamiese werk van die Heilige Gees in hierdie eeu dui op die grootsheid van die werk van die Heilige Gees tot dusver en dat ons die stryd moet verskerp om nie te verloor wat ons tans het nie.
Prandtl number variation on transient forced convection flow in a fluid valve using nanofluid
Authors: Nasrin Rehena , Alim M.A. , Chamkha Ali J.
Published: December 2012

A transient numerical study is conducted to investigate the transport mechanism of forced convection in a fluid valve filled with water-CuO nanofluid. The flow enters from one inlet at the left with uniform temperature and velocity Ti and Ui, respectively, but can leave the valve through two outlets at the right. The upper and lower boundaries of the valve are heated with constant temperature Th while the remaining walls are  perfectly insulated. The numerical approach is based on the finite element technique with Galerkin’s weighted residual simulation. Solutions are obtained for the variation of Prandtl number (Pr) while Reynolds number (Re) and solid volume fraction (φ ) are fixed at 100 and 5%. The streamlines, isotherm plots, the local and average Nusselt number, mean temperature of the fluids (base fluid and nanofluid) and subdomain velocity with the variation of non-dimensional time (τ) are presented and discussed. It is found that the rate of heat transfer in the fluid valve reduces for longer time periods.Keywords: Water-CuO nanofluid, forced convection, fluid valve, transient analysis.
The estimation of the return on firms’ investments – as to ISO 9001
Authors: Santos G. , Costa B. , Leal A.
Published: December 2012

The aim of this paper was to estimate the return on investment in QMS (quality management systems) certification undertaken in Portuguese firms, according to the ISO 9000 series. A total of 426 certified Portuguese firms were surveyed. The response rate was 61.03 percent. The different payback periods were validated through statistical analysis and the relationship between expected and perceived payback periods was discussed. This study suggests that a firm’s sector of activity, size and degree of internationalization are related to the length of the investment in QMS certification recovery period. Furthermore, our findings suggest, that the time taken to obtain the certification is not directly related to the economic component of the certification. The majority of Portuguese firms (58.9%) took up to three years to recoup their investment and 35.5% of companies said they had not yet recovered the initial investment made. The recoup of investment was measured by the increase in the number of customers and consequent volume of deliveries, improved profitability and productivity of the company, improvement of competitive position and performance (cost savings), reduction in the number of external complaints and internal defects/scrap, achievement of some important clientele, among others. We compared our work to similar studies undertaken in other countries. This paper provides a contribution to the research related to the return on investment for costs related to the certification QMS according to ISO 9000. This paper provides a valuable contribution to the field and is one of the first studies to undertake this type of analysis in Portugal.Keywords: Quality Awareness; ISO 9000 series; Return on Investment; Portugal
Fuel Conditions Associated with Native and Exotic Grasses in a Subtropical Dry Forest in Puerto Rico
Authors: Thaxton Jarrod M. , Van Bloem Skip J. , Whitmire Stefanie
Published: December 2012

Exotic grasses capable of increasing frequency and intensity of anthropogenic fire have invaded subtropical and tropical dry forests worldwide. Since many dry forest trees are susceptible to fire, this can result in decline of native species and loss of forest cover. While the contribution of exotic grasses to altered fire regimes has been well documented, the role of native grasses in contributing to fuel loads in dry forest has received little attention. We assessed differences in fuel conditions among native and exotic grasses within a subtropical dry forest preserve in Puerto Rico. We quantified fine fuel loads, fuel continuity, and seasonal changes in percent dead grass among the following grass patch types: (1) native grass with no known history of recent fire, (2) exotic grass that had burned once (single burn), and (3) exotic grass that burns frequently. Sampling was conducted during one wet season (August to October 2008) and again in the following dry season (February to March 2009). Overall, fine fuel loading was highest in native grass, but this was due to woody fuels rather than grass fuels. Percent of dead grass fuels increased with the transition from wet to dry season, and this increase was more pronounced for exotic grasses. Fuel continuity was highest in frequently burned exotic grass. Differences in grass phenology and fuel continuity may contribute to differences in fire frequency among native and exotic grass patches. Fuel management focused on prescribed fire should be used in conjunction with restoration of tree canopy to reduce fuels and limit development of a grass-fire cycle.
Irreversible impacts of heat on the emissions of monoterpenes, sesquiterpenes, phenolic BVOC and green leaf volatiles from several tree species
Authors: Kleist E. , Mentel T. F. , Andres S. , Bohne A. , Folkers A. , Kiendler-Scharr A. , Rudich Y. , Springer M. , Tillmann R. , Wildt J.
Published: December 2012

Abstract. Climate change will induce extended heat waves to parts of the vegetation more frequently. High temperatures may act as stress (thermal stress) on plants changing emissions of biogenic volatile organic compounds (BVOCs). As BVOCs impact the atmospheric oxidation cycle and aerosol formation, it is important to explore possible alterations of BVOC emissions under high temperature conditions. Applying heat to European beech, Palestine oak, Scots pine, and Norway spruce in a laboratory setup either caused the well-known exponential increases of BVOC emissions or induced irreversible changes of BVOC emissions. Considering only irreversible changes of BVOC emissions as stress impacts, we found that high temperatures decreased the de novo emissions of monoterpenes, sesquiterpenes and phenolic BVOC. This behaviour was independent of the tree species and whether the de novo emissions were constitutive or induced by biotic stress. In contrast, application of thermal stress to conifers amplified the release of monoterpenes stored in resin ducts of conifers and induced emissions of green leaf volatiles. In particular during insect attack on conifers, the plants showed de novo emissions of sesquiterpenes and phenolic BVOCs, which exceeded constitutive monoterpene emissions from pools. The heat-induced decrease of de novo emissions was larger than the increased monoterpene release caused by damage of resin ducts. For insect-infested conifers the net effect of thermal stress on BVOC emissions could be an overall decrease. Global change-induced heat waves may put hard thermal stress on plants. If so, we project that BVOC emissions increase is more than predicted by models only in areas predominantly covered with conifers that do not emit high amounts of sesquiterpenes and phenolic BVOCs. Otherwise overall effects of high temperature stress will be lower increases of BVOC emissions than predicted by algorithms that do not consider stress impacts.
Carbon emissions from land use and land-cover change
Authors: Houghton R. A. , House J. I. , Pongratz J. , van der Werf G. R. , DeFries R. S. , Hansen M. C. , Le Quéré C. , Ramankutty N.
Published: December 2012

Abstract. The net flux of carbon from land use and land-cover change (LULCC) accounted for 12.5% of anthropogenic carbon emissions from 1990 to 2010. This net flux is the most uncertain term in the global carbon budget, not only because of uncertainties in rates of deforestation and forestation, but also because of uncertainties in the carbon density of the lands actually undergoing change. Furthermore, there are differences in approaches used to determine the flux that introduce variability into estimates in ways that are difficult to evaluate, and not all analyses consider the same types of management activities. Thirteen recent estimates of net carbon emissions from LULCC are summarized here. In addition to deforestation, all analyses considered changes in the area of agricultural lands (croplands and pastures). Some considered, also, forest management (wood harvest, shifting cultivation). None included emissions from the degradation of tropical peatlands. Means and standard deviations across the thirteen model estimates of annual emissions for the 1980s and 1990s, respectively, are 1.14 ± 0.23 and 1.12 ± 0.25 Pg C yr−1 (1 Pg = 1015 g carbon). Four studies also considered the period 2000–2009, and the mean and standard deviations across these four for the three decades are 1.14 ± 0.39, 1.17 ± 0.32, and 1.10 ± 0.11 Pg C yr−1. For the period 1990–2009 the mean global emissions from LULCC are 1.14 ± 0.18 Pg C yr−1. The standard deviations across model means shown here are smaller than previous estimates of uncertainty as they do not account for the errors that result from data uncertainty and from an incomplete understanding of all the processes affecting the net flux of carbon from LULCC. Although these errors have not been systematically evaluated, based on partial analyses available in the literature and expert opinion, they are estimated to be on the order of ± 0.5 Pg C yr−1.
Occurrence, sources and transport pathways of natural and anthropogenic hydrocarbons in deep-sea sediments of the Eastern Mediterranean Sea
Authors: Parinos C. , Gogou A. , Bouloubassi I. , Pedrosa-Pàmies R. , Hatzianestis I. , Sànchez-Vidal A. , Rousakis G. , Velaoras D. , Krokos G. , Lykousis V.
Published: December 2012

Abstract. Surface sediments collected from deep basins (22 stations, 1018–4087 m depth) of the Eastern Mediterranean Sea (EMS) were analyzed for aliphatic, triterpenoid and polycyclic aromatic hydrocarbons (PAHs) as tracers of natural and anthropogenic inputs. Concentrations of total aliphatic hydrocarbons (TAHC), n-alkanes (NA) and the Unresolved Complex Mixture (UCM) of aliphatic hydrocarbons ranged from 1.34 to 49.2 µg g−1, 145 to 4810 ng g−1 and 0.73 to 36.7 µg g−1, respectively, while total PAHs (TPAH25) concentrations ranged from 11.6 to 223 ng g−1. Molecular profiles of aliphatic hydrocarbons and PAHs reflect the contribution of both natural (epicuticular plant waxes) and anthropogenic (degraded petroleum products, unburned fossil fuels and combustion of petroleum, grass, wood and coal) compounds in deep EMS sediments, with hydrocarbon mixtures displaying significant regional variability. Hydrocarbon concentrations correlated significantly with the Total Organic Carbon (TOC) content of sediments, indicating that organic carbon exerts an important control on their transport and fate in the study area, while strong sub-basin and mesoscale variability of water masses also impact their regional characteristics. Major findings of this study support that deep basins/canyons of the EMS could act as traps of both natural and anthropogenic hydrocarbons.
Interannual variation in the epibenthic megafauna at the shallowest station of the HAUSGARTEN observatory (79° N, 6° E)
Authors: Meyer K. S. , Bergmann M. , Soltwedel T.
Published: December 2012

Abstract. Epibenthic megafauna play an important role in the deep-sea environment and contribute significantly to benthic biomass, but their population dynamics are still understudied. We used a towed deep-sea camera system to assess the population densities of epibenthic megafauna in 2002, 2007 and 2012 at the shallowest station (HG I, ~ 1300 m) of the deep-sea observatory HAUSGARTEN, in the eastern Fram Strait. Our results indicate that the overall density of megafauna was significantly lower in 2007 than in 2002, but was significantly higher in 2012, resulting in overall greater megafaunal density in 2012. Different species showed different patterns in population density, but the relative proportions of predator/scavengers and suspension-feeding individuals were both higher in 2012. Variations in megafaunal densities and proportions are likely due to variation in food input to the sea floor, which decreased slightly in the years preceding 2007 and was greatly elevated in the years preceding 2012. Both average evenness and diversity increased over the time period studied, which indicates that HG I may be food-limited and subject to bottom-up control. The varying dynamics of different species may have been caused by differential capacities of populations to respond to increased food input through either recruitment or migration.
Estimating the flood frequency distribution at seasonal and annual time scales
Authors: Baratti E. , Montanari A. , Castellarin A. , Salinas J. L. , Viglione A. , Bezzi A.
Published: December 2012

Abstract. We propose an original approach to infer the flood frequency distribution at seasonal and annual time scale. Our purpose is to estimate the peak flow that is expected for an assigned return period T, independently of the season in which it occurs (i.e. annual flood frequency regime), as well as in different selected sub-yearly periods (i.e. seasonal flood frequency regime). While a huge literature exists on annual flood frequency analysis, few studies have focused on the estimation of seasonal flood frequencies despite the relevance of the issue, for instance when scheduling along the months of the year the construction phases of river engineering works directly interacting with the active river bed, like for instance dams. An approximate method for joint frequency analysis is presented here that guarantees consistency between fitted annual and seasonal distributions, i.e. the annual cumulative distribution is the product of the seasonal cumulative distribution functions, under the assumption of independence among floods in different seasons. In our method the parameters of the seasonal frequency distributions are fitted by maximising an objective function that accounts for the likelihoods of both seasonal and annual peaks. In contrast to previous studies, our procedure is conceived to allow the users to introduce subjective weights to the components of the objective function in order to emphasize the fitting of specific seasons or of the annual peak flow distribution. An application to the time series of the Blue Nile daily flows at the Sudan–Ethiopia border is presented.
Imbalance of energy and momentum source terms of the sea wave transfer equation for fully developed seas
Authors: Caudal G. V.
Published: December 2012

Abstract. In the concept of full development, the sea wave spectrum is regarded as a nearly stationary solution of the wave transfer equation, where source and sink terms should be in balance with respect to both energy and momentum. Using a two-dimensional empirical sea wave spectral model at full development, this paper performs an assessment of the compatibility of the energy and momentum budgets of sea waves over the whole spectral range. Among the various combinations of model functions for wave breaking and wind source terms tested, not one is found to fulfill simultaneously the energy and momentum balance of the transfer equation. Based on experimental and theoretical grounds, wave breaking is known to contribute to frequency downshift of a narrow-banded wave spectrum when the modulational instability is combined with wave breaking. On those grounds, it is assumed that, in addition to dissipation, wave breaking produces a spectral energy flux directed toward low wavenumbers. I show that it is then possible to remove the energy and momentum budget inconsistency, and correspondingly the required strength of this spectral flux is estimated. Introducing such a downward spectral flux permits fulfilling both energy and momentum balance conditions. Meanwhile, the consistency between the transfer equation and empirical spectra, estimated by means of a cost function K, is either improved or slightly reduced, depending upon the wave breaking and wind source terms chosen. Other tests are performed in which it is further assumed that wave breaking would also be associated with azimuthal diffusion of the spectral energy. This would correspondingly reduce the required downward spectral flux by a factor of up to 5, although it would not be able to remove it entirely.
Application of soil quality indices to assess the status of agricultural soils irrigated with treated wastewaters
Authors: Morugán-Coronado A. , Arcenegui V. , García-Orenes F. , Mataix-Solera J. , Mataix-Beneyto J.
Published: December 2012

Abstract. The supply of water is limited in some parts of the Mediterranean region, such as southeastern Spain. The use of treated wastewater for the irrigation of agricultural soils is an alternative to using better-quality water, especially in semi-arid regions. On the other hand, this practice can modify some soil properties, change their relationships, the equilibrium reached and influence soil quality. In this work two soil quality indices were used to evaluate the effects of irrigation with treated wastewater in soils. The indices were developed studying different soil properties in undisturbed soils in SE Spain, and the relationships between soil parameters were established using multiple linear regressions. This study was carried out in three areas of Alicante Province (SE Spain) irrigated with wastewater, including four study sites. The results showed slight changes in some soil properties as a consequence of irrigation with wastewater, the obtained levels not being dangerous for agricultural soils, and in some cases they could be considered as positive from an agronomical point of view. In one of the study sites, and as a consequence of the low quality wastewater used, a relevant increase in soil organic matter content was observed, as well as modifications in most of the soil properties. The application of soil quality indices indicated that all the soils of study sites are in a state of disequilibrium regarding the relationships between properties independent of the type of water used. However, there were no relevant differences in the soil quality indices between soils irrigated with wastewater with respect to their control sites for all except one of the sites, which corresponds to the site where low quality wastewater was used.
Effective antioxidant phenolic compounds in selected varieties of apples
Authors: Bončí­ková Dominika , Tóth Tomáš , Tomáš Ján , Suleiman Dalaram , Tóth Juraj , Slávik Marek
Published: December 2012

Polyphenolic compounds are effective antioxidant regarding their ability to reat with free radicals of fatty acid and oxygen(free radical scavening effect). One of the richest source of polyphenolic compounds in human nutrition are apples (Malus Mill.). Our work was focused on determinaton of total polyphenols contents and antioxidant activity and evaluate the presence of dislocation active antioxidant components in four of selected varieties of apples Idared, Jonagold, Pinova, Topaz (peel extract and pulp extract).The total contents of phenolic compounds,determined according to the Folin-Ciocalteu reagent spectrofotometric by Lachman and antioxidant activity was measured using a free radical used in this study was 2,2-diphenyl-1-picrylhydrazyl (DPPH). Average content of total polyphenols in selected varieties of apples was 622,67 mg.kg-1 (peel extract) and 568,7mg.kg-1 (pulp etract) after harvesting. Relationships between content of total polyphenols and antioxidant activity is affected by varietal difrences.
Effect of selected feed additives on internal quality parameters of table eggs
Authors: Arpášová Henrieta , Kačániová Miroslava , Haščí­k Peter , Šidlová Veronika
Published: December 2012

The aim of our experiment was to evaluate under experimental conditions the influence of probiotic preparation based on lactobacillus, oregano essential oil, sumac (Rhus coriaria), propolis and pollen on egg quality parameters of laying hens hybrid Lohman Brown. For housing hens (n ​​= 60) three storey enriched battery cage was used in which hens were divided in groups (n = 10). Total floor space given to one animal was 943.2 cm2. In the control group of hens complete feed mixtures without any additions were fed. In the first experimental group complete feed mixture was enriched with probiotic lactobacilli based preparation in a dose of 0.5 g.kg-1. In the second experimental group oregano essential oil was added to the feed mixture at a dose of 0.5 ml.kg-1. The third experimental group was enriched with 1 % concentration of sumac (Rhus coriaria). The fourth experimental group was enriched with 0.2 g of propolis extract per 1 kg of feed mixture and the fifth experimental group was supplemented by pollen extract of the same dose. All groups were fed ad libitum. Eggs quality indicators observed were egg weight (g), yolk percentage (%), yolk index, white percentage (%), whites index and Haugh units of whites (HJ). The results show that addition of probiotics positively, although not significantly, influenced the average egg weight. The addition of oregano oil and sumac insignificantly decreased egg weight (P>0.05), the values ​​of the other eggs quality indicators were comparable with the control group. Supplementation of feed mixture with propolis as well as phytobiotics insignificantly decreased egg weight, but its addition improved the internal quality parameters as the yolks and whites index, whose average values ​​were in this group, although not statistically significantly higher (P>0.05).
Xenobiotics and biogenic elements in raw cow's milk
Authors: Lukáčová Anetta , Gajdošová Dominika , Massányi Peter , Golian Jozef , Greń Agnieszka
Published: December 2012

This paper presents the concentration some toxic and biogenic elements in milk from Nitra region. The aim of this investigation was to evaluate 30 samples of raw milk with fat contents 3.8% obtained from milk machine in the Nitra region. Samples were analyzed for metal contents using atomic absorption spectrophotometry (AAS). In comparison with maximum acceptable concentration for milk in the food codex of the Slovak republic, the level of contamination with cadmium was exceeded and reached the value 0.221 µg.ml-1. The copper content ranged from 1.201 µg.ml-1 to 5.810 µg.ml-1 and the average concentration reached 3.793 µg.ml-1.  Iron had an average of 1.824 µg.ml-1. Overall in all milk samples high correlations were found. Between positive correlation (0.7019) and negative correlation between of nickel and potassium concentration in raw milk (-0.72) was found.
Synthesis and Characterization of Telechelic Oligoethers with Terminal Cinnamylidene Acetic Acid Moieties
Authors: Melchert Christian , Yongvongsoontorn Nunnarpas , Behl Marc , Lendlein Andreas
Published: December 2012

Purpose

The formation of photoresponsive hydrogels were reported by irradiation of star-shaped poly(ethylene glycol)s with terminal cinnamylidene acetic acid (CAA) groups, which are capable of a photoinduced [2+2] cycloaddition. In this study we explored whether oligo(ethylene glycol)s and oligo(propylene glycol)s of varying molecular architecture (linear or star-shaped) or molecular weights could be functionalized with CAA as terminal groups by esterification or by amide formation.

Methods

Oligo(ethylene glycol) (OEG) and oligo(propylene glycol) (OPG) with varying molecular architecture (linear, star-shaped) and weight average molecular weights between 1000 and 5000 g.mol−1 were functionalized by means of esterification of hydroxyl or amine endgroups with cinnamylidene acetic acid (CAA) or cinnamylidene acetyl chloride (CAC) as telechelic endgroups. The chemical structure, thermal properties, and molecular weights of the oligoethers obtained were determined by NMR spectroscopy, UV spectroscopy, DSC, and MALDI-TOF.

Results

CAA-functionalized linear and star-shaped OEGs or OPGs could be obtained with a degree of functionalization higher than 90%. In MALDI-TOF measurements an increase in Mw of about 150 g·mol−1 (for each terminal end) after the functionalization reaction was observed. OEGCAA and OPGCAA showed an increase in glass transition temperature (Tg) from about –70°C to –50°C, compared to the unfunctionalized oligoethers. In addition, the melting temperature (Tm) of OEGCAA decreased from about 55°C to 30°C, which can be accounted for by the hampered crystallization of the precursors because of the bulky CAA end groups as well as by the loss of the hydroxyl telechelic end groups.

Conclusion

The synthesis of photoresponsive oligoethers containing cinnamylidene acetic acid as telechelic endgroup was reported and high degrees of functionalization could be achieved. Such photosensitive oligomers are promising candidates as reactive precursors, for the preparation of biocompatible high molecular weight polymers and polymer networks.
Bioinspired Polymeric Surface Patterns for Medical Applications
Authors: Kroner Elmar , Kaiser Jessica S. , Fischer Sarah C. L. , Arzt Eduard
Published: December 2012

Purpose

A powerful principle in nature is the presence of surface patterns to improve specific characteristics or to enable completely new functions. Here, we present two case studies where bioinspired surface patterns based on the adhesive system of geckos may be applied for biomedical applications: residue-free adhesion to skin and gecko-inspired suture threads for knot-free wound closure.

Methods

Gecko-inspired skin adhesives were fabricated by soft lithography of polydimethylsiloxane with successive inking and dipping steps. Their adhesion was measured using a home built adhesion tester designed for patterned surfaces. Preliminary lap shear tests on the back of a human hand were also performed. Commercial suture threads from different materials were patterned in the group of A. del Campo at the Max Planck Institute for Polymer Research (Mainz, Germany) using oxygen plasma. The treated threads were pulled through artificial skin in both directions measuring the peak force and the pull through force.

Results and Conclusions

Unpatterned reference samples of the skin adhesive did not stick to human skin, while the patterned samples all showed notable adhesion up to 1.2 Newton for a sample size of approximately 3 cm2. First results with the patterned suture threads indicated that the surface patterning of the thread has only a minor effect on the pull-through forces. To achieve knot-free sewing the surface geometry of the suture threads needs to be optimized and more realistic testing procedures, e.g. testing on human skin, are necessary.
Proliferation and Osteoblastic Differentiation of hMSCs on Cellulose-Based Hydrogels
Authors: Raucci Maria Grazia , Alvarez-Perez Marco Antonio , Demitri Christian , Sannino Alessandro , Ambrosio Luigi
Published: December 2012

Purpose

The aim of this project was to study the proliferation and differentiation of human Mesenchymal Stem Cells (hMSCs) onto a cellulose-based hydrogel for bone tissue engineering.

Methods

Modified-cellulose hydrogel was prepared via double esterification crosslinking using citric acid. The response of hMSCs in terms of cell proliferation and differentiation into osteoblastic phenotype was evaluated by using Alamar blue™ assay and alkaline phosphatase (ALP) activity.

Results

The results showed that CMCNa and CMCNa_CA have no negative effect on hMSC, adhesion and proliferation. Moreover, the increase of the ALP expression for CMCNa_CA confirms the ability of the hydrogels to support the osteoblastic differentiation.

Conclusions

The cellulose-based hydrogels have a potential application as filler in bone tissue regeneration.
Manufacturing Light Concrete with PET Aggregate
Authors: Casanova-del-Angel Francisco , Vázquez-Ruiz Jorge Luis
Published: December 2012

The manufacture of concrete using a polymer instead of a stony coarse aggregate known as gravel is presented. Polyethylene terephthalate (PET) is the polymer used, recycling soft drink containers with sufficient tenacity. PET is a material commonly used by engineers as a structural element, not as an aggregate. The research work revealed that PET aggregate produces good quality mixtures with lower volumetric weight but mechanical behavior similar to that of natural concrete with adequate granulometry. The water/cement (W/C) ratio is lower for light concretes than for natural concrete. Regarding stress and Flexural strength, it was found that for 300 kg/cm3 and higher cement consumption, which may be due to the fact that at low W/C ratios, the coarse aggregate behavior prevails, while at high W/C ratios, the paste behavior prevails. This leads us to the fact that PET aggregate is best applied on low cement consumption up to 300 kg/m3, since expensive mixtures for higher consumption may result from use on higher consumption. Modulus of elasticity for light concretes is lower than for natural concretes. Deformations are lower for light concretes than for natural concretes. A feature of using PET to substitute coarse aggregate is volumetric weight, since it is 68.88% lighter than concrete with natural aggregates.
Circadian Rhythms and Obesity in Mammals
Authors: Froy Oren
Published: December 2012

Obesity has become a serious public health problem and a major risk factor for the development of illnesses, such as insulin resistance and hypertension. Attempts to understand the causes of obesity and develop new therapeutic strategies have mostly focused on caloric intake and energy expenditure. Recent studies have shown that the circadian clock controls energy homeostasis by regulating the circadian expression and/or activity of enzymes, hormones, and transport systems involved in metabolism. Moreover, disruption of circadian rhythms leads to obesity and metabolic disorders. Therefore, it is plausible that resetting of the circadian clock can be used as a new approach to attenuate obesity. Feeding regimens, such as restricted feeding (RF), calorie restriction (CR), and intermittent fasting (IF), provide a time cue and reset the circadian clock and lead to better health. In contrast, high-fat (HF) diet leads to disrupted circadian expression of metabolic factors and obesity. This paper focuses on circadian rhythms and their link to obesity.