bluuebunny/crossref_metadata_2025 huggingface dataset:
Understanding the Relationships Among Various Design Components in a Game-Based Learning Environment
Authors: Ma Yuxin , Williams Douglas , Prejean Louise
Published: May 2012

Designing an electronic, game-based learning environment is a multi-disciplinary effort that involves the consideration of various theories and models in multiple domains. Taking these theories and models into consideration adds to the complexity of the development process. Which elements should designers consider first? How do designers reconcile the demands and conflicts of different design components? Game-based learning environments are a relatively new territory for research and development. This paper reports an analysis of the decision making related to the interplay of various design components in developing Conquest of Coastlands (CoC), an electronic, game-based learning environment. The analysis may help designers better understand the intricate relationships among various design components involved in creating game-based learning environments.
Dynamic Roles of Type I and Type II IFNs in Early Infection withMycobacterium tuberculosis
Authors: Desvignes Ludovic , Wolf Andrea J. , Ernst Joel D.
Published: May 2012

Although the protective role of type II IFN, or IFN-γ, against Mycobacterium tuberculosis has been established, the effects of type I IFNs are still unclear. One potential confounding factor is the overlap of function between the two signaling pathways. We used mice carrying null mutations in the type I IFNR, type II IFNR, or both and compared their immune responses to those of wild-type mice following aerosol infection with M. tuberculosis. We discovered that, in the absence of a response to IFN-γ, type I IFNs play a nonredundant protective role against tuberculosis. Mice unable to respond to both types of IFNs had more severe lung histopathology for similar bacterial loads and died significantly earlier than did mice with impaired IFN-γ signaling alone. We excluded a role for type I IFN in T cell recruitment, which was IFN-γ dependent, whereas both types of IFNs were required for optimal NK cell recruitment to the lungs. Type I IFN had a time-dependent influence on the composition of lung myeloid cell populations, in particular by limiting the abundance of M. tuberculosis-infected recruited macrophages after the onset of adaptive immunity. We confirmed that response to IFN-γ was essential to control intracellular mycobacterial growth, without any additional effect of type I IFN. Together, our results imply a model in which type I IFN limit the number of target cells that M. tuberculosis can infect in the lungs, whereas IFN-γ enhances their ability to restrict bacterial growth.
Ecological Risk Analysis Using the Vegetable Bioindicator Lolium multiflorum
Authors: Rodrigues Magali S. , Raya-Rodriguez M. T. M.
Published: May 2012

This work was starting from January, 2005 to March, 2008, during 39 months of monitoring. This evaluation was developed around of Petroleum Refinery area, in one fixed sample station localized in Esteio (29°49’16” S 51°08’09”) cities, Rio Grande do Sul state, Brazil. The objective of this work was to develop and apply a model Ecological Risk Analysis (ERA) to classify the risks related to the atmospheric emissions in industrial areas using the vegetable bioindicator Lolium multiflorum. The proposed model for the ecologic risk evaluation associates the information from stressors’ effects, which come from sulfur compounded gases emissions, at the receptors, that is, the vegetable bioindicator tissue. It was evaluated in the vegetable bioindicators parameter; sulfur concentration accumulated in the plants, classified in the study as “answers data”. These were linked to the SO2 atmosphere concentration, which generate the “consequence data”; Toxic Potential Unit (TPU) and Exposure Toxic Unit (ETU). The integration was made using the statistics correspondence multiple variable analysis that demonstrate indications of risks for the vegetation localized around the refinery, when it was exposed an TPU higher than the unit.
Acute Sensitivity to Nitokra sp Benthic Copepod to Potassium Dichromate and Ammonia Chloride
Authors: Sousa E. C. P. M. , Zaroni L. P. , Bergmann Filho T. U. , Marconato L. A. , KirschBaum A. A. , Gasparro M. R.
Published: May 2012

The present study assesses acute toxicity of non-ionized ammonia and potassium dichromate using the estuarine benthic copepod Nitokra sp from laboratory cultures. Bioassays with non-ionized ammonia sensitivity were carried out, and the mean. Bioassays with non-ionized ammonia sensitivity were carried out, and the mean of LC(I)50-96h was 1.7 mg.L-1. – LC(I)50-96h was 1.7 mg.L-1. Potassium dichromate was used as reference substance in two distinct periods of exposure and the mean LC(I)50-48h and LC(I)50-96h values were 55.61 mg.L-1and 21.70 mg.L-1, respectively. The organism showed sensitivity to the toxic agents used and good reproducibility of results, indispensable factors for use in ecotoxicological assays.
A new scheme for sulphur dioxide retrieval from IASI measurements: application to the Eyjafjallajökull eruption of April and May 2010
Authors: Carboni E. , Grainger R. , Walker J. , Dudhia A. , Siddans R.
Published: May 2012

Abstract. A new algorithm for the retrieval of sulphur dioxide (SO2) from IASI data has been developed based on optimal estimation theory. It uses the IASI channels between 1000–1200 and 1300–1410 cm−1. These regions include the two SO2 absorption bands (the ν1 and ν3 bands) centred at about 7.3 and 8.7 microns, respectively. The retrieval assumes a Gaussian distribution for the vertical SO2 profile and returns the SO2 column amount in Dobson units (DU) and the altitude of the plume in millibar (mb). Radiative transfer computations that generate the forward modelled spectra (against which the measurements are compared) are based on RTTOV and ECMWF meteorological data. The retrieval includes a comprehensive error budget for every pixel. This is derived from an error covariance matrix that is based on the SO2-free climatology of the differences between the IASI and forward modelled spectra. The IASI forward model includes the ability to simulate a cloud or ash layer in the atmosphere. This feature is used to illustrate that: (1) the SO2 retrieval is not affected by underling cloud but is affected if the SO2 is within or below a cloud layer; (2) it is possible to discern if ash (or other atmospheric constituents not considered in the error covariance matrix) affects the retrieval using quality control based on the fit of the measured spectrum by the forward modelled spectrum. In this work the algorithm is applied to follow the behaviour of SO2 plumes in atmosphere for the Eyjafjallajökull eruption during April and May 2010 in terms of SO2 amount. From 14 April to 4 May (during phase I and II of the eruption) the total amount of SO2 present in atmosphere, estimated by IASI measurements, is generally below 0.2 Tg. During the last part of the eruption (phase III) the values are one order of magnitude higher, with a maximum of 0.14 Tg measured on 9 May with the afternoon orbits.
Inter-comparison of two high-accuracy fast-response spectroscopic sensors of carbon dioxide: a case study
Authors: Flowers B. A. , Powers H. H. , Dubey M. K. , McDowell N. G.
Published: May 2012

Abstract. Tunable diode laser absorption (TDL) and cavity ring-down spectroscopic (CRDS) sensors for atmospheric carbon dioxide were co-deployed during summer and fall of 2010 in field and laboratory conditions at Los Alamos National Laboratory. Both sensors were characterized for accuracy and precision for ambient carbon dioxide measurements at ground level and compared using both laboratory and ambient field data. After post-processing that included water vapor correction and calibration to WMO reference standards, overall mean [12C16O2] = 392.05 ± 8.92 ppm and [12C16O2] = 392.22 ± 9.05 ppm were observed between 29 July and 16 August 2010. The mean difference between the CRDS and TDL data for 12CO2 was 0.04 ± 1.80 ppm (±1σ in 60 s) for ambient field data, demonstrating the sensors meet the WMO/IAEA compatibility standard. The observations show over the 19-day period the [CO2]CRDS'/[CO2]TDL ratio exhibits a Gaussian distribution centered at x0 = 1.003 ± 3.38 × 10−5 (±1σ), indicating the ratio is dominated by random noise as opposed to a bias in the output of either sensor. The CRDS sensor is capable of measuring [12C16O2] to a precision of 23 ppb in 1 min and decreases to 6.5 ppb in 58 min. At one and 58-min, the TDL exhibits precisions of 29 ppb and 53 ppb. The CRDS is compact, fast, and stable; the TDL is larger and requires frequent calibrations to maintain its precision. The sensors also exhibit consistent hourly averaged diurnal values underscoring the interplay of biological, anthropogenic, and transport processes regulating CO2 at the site.
Finite element simulation of a local scale air quality model over complex terrain
Authors: Oliver A. , Montero G. , Montenegro R. , Rodríguez E. , Escobar J. M. , Perez-Foguet A.
Published: May 2012

Abstract. In this paper we propose a finite element method approach for modelling the air quality in a local scale over complex terrain. The area of interest is up to tens of kilometres and it includes pollutant sources. The proposed methodology involves the generation of an adaptive tetrahedral mesh, the computation of an ambient wind field, the inclusion of the plume rise effect in the wind field, and the simulation of transport and reaction of pollutants. We apply our methodology to simulate a fictitious pollution episode in La Palma island (Canary Island, Spain).
A new marine ecosystem model for the University of Victoria Earth system climate model
Authors: Keller D. P. , Oschlies A. , Eby M.
Published: May 2012

Abstract. Earth system climate models (ESCMs) are valuable tools that can be used to gain a better understanding of the climate system, global biogeochemical cycles, and how anthropogenically-driven changes may affect them. Here we describe improvements made to the marine biogeochemical ecosystem component of the University of Victoria's ESCM (version 2.9). Major changes include corrections to the code and equations describing phytoplankton light limitation and zooplankton grazing, the implementation of a more realistic zooplankton growth and grazing model, and the implementation of an iron limitation scheme to constrain phytoplankton growth. The new model is evaluated after a 10 000-yr spin-up and compared to both the previous version and observations. For the majority of biogeochemical tracers and ecosystem processes the new model shows significant improvements when compared to the previous version and evaluated against observations. Many of the improvements are due to better simulation of seasonal changes in higher latitude ecosystems and the effect that this has on ocean biogeochemistry. This improved model is intended to provide a basic new ESCM model component, which can be used as is or expanded upon (i.e., the addition of new tracers), for climate change and biogeochemical cycling research.
Hydrological heterogeneity in Mediterranean reclaimed slopes: runoff and sediment yield at the patch and slope scales along a gradient of overland flow
Authors: Merino-Martín L. , Moreno-de las Heras M. , Pérez-Domingo S. , Espigares T. , Nicolau J. M.
Published: May 2012

Abstract. Hydrological heterogeneity is recognized as a fundamental ecosystem attribute in drylands controlling the flux of water and energy through landscapes. Therefore, mosaics of runoff and sediment source patches and sinks are frequently identified in these dry environments. There is a remarkable scarcity of studies about hydrological spatial heterogeneity in restored slopes, where ecological succession and overland flow are interacting. We conducted field research to study the hydrological role of patches and slopes along an "overland flow gradient" (gradient of overland flow routing through the slopes caused by different amounts of run-on coming from upslope) in three reclaimed mining slopes of Mediterranean-continental climate. We found that runoff generation and routing in non-rilled slopes showed a pattern of source and sink areas of runoff. Such hydrological microenvironments were associated with seven vegetation patches (characterized by plant community types and cover). Two types of sink patches were identified: shrub Genista scorpius patches could be considered as "deep sinks", while patches where the graminoids Brachypodium retusum and Lolium perenne dominate were classified as "surface sinks" or "runoff splays". A variety of source patches were also identified spanning from "extreme sources" (Medicago sativa patches; equivalent to bare soil) to "poor sources" (areas scattered by dwarf-shrubs of Thymus vulgaris or herbaceous tussocks of Dactylis glomerata). Finally, we identified the volume of overland flow routing along the slope as a major controlling factor of "hydrological diversity" (heterogeneity of hydrological behaviours quantified as Shannon diversity index): when overland flow increases at the slope scale hydrological diversity diminishes.
Seismicity at the Rwenzori Mountains, East African Rift: earthquake distribution, magnitudes and source mechanisms
Authors: Lindenfeld M. , Rümpker G. , Batte A. , Schumann A.
Published: May 2012

Abstract. We have analysed the microseismic activity within the Rwenzori Mountains area in the western branch of the East African Rift. Seismogram recordings from a temporary array of up to 27 stations reveal approximately 800 events per month with local magnitudes ranging from –0.5 to 5.1. The earthquake distribution is highly heterogeneous. The majority of located events lie within faults zones to the East and West of the Rwenzoris with the highest seismic activity observed in the northeastern area, where the mountains are in contact with the rift shoulders. The hypocentral depth distribution exhibits a pronounced peak of seismic energy release at 15 km depth. The maximum extent of seismicity ranges from 20 to 32 km and correlates well with Moho depths that were derived from teleseismic receiver functions. We observe two general features: (i) beneath the rift shoulders seismicity extends from the surface down to ca. 30 km depth; (ii) beneath the rift valley seismicity is confined to depths greater than 10 km. From the observations there is no indication for a crustal root beneath the Rwenzori Mountains. The magnitude frequency distribution reveals a b-value of 1.1, which is consistent with the hypothesis that part of the seismicity is caused by magmatic processes within the crust. Fault plane solutions of 304 events were derived from P-polarities and SV/P amplitude ratios. More than 70 % of the source mechanisms exhibit pure or predominantly normal faulting. T-axis trends are highly uniform and oriented WNW-ESE, which is perpendicular to the rift axis and in good agreement with kinematic rift models. At the northernmost part of the region we observe a rotation of the T-axis trends to NEN-SWS, which may be indicative of a local perturbation of the regional stress field.
Nephron-Sparing Surgery: Our Experience
Authors: Crestani Alessandro , Guttilla Andrea , Dal Moro Fabrizio , Valotto Claudio , Zattoni Filiberto
Published: May 2012

Objectives

To analyze the data of our department with regard to the treatment of kidney cancer, with particular attention to nephron-sparing surgery (NSS). Data of initial experience on robot-assisted partial nephrectomy (RAPN) were also analyzed.

Methods

Between January 2005 and December 2010, at the Urology Clinic of Padua, 780 procedures for kidney cancer were performed: 462 radical nephrectomies (RN), 289 open partial nephrectomies (OPN), and 29 robot-assisted partial nephrectomies (RAPN). Between January 2010 and July 2011 41 RAPN as well as 38 OPN were performed.

Results

The average volume of tumors treated with RAPN was 2.17 cm, 1.98 cm, and 2.78 cm in the first, second, and third half-year, respectively. The mean operative time was 220 minutes, 200 minutes, and 180 minutes in the first, second, and third half-year, respectively. The average warm ischemia time was 24 minutes, 22 minutes, and 21 minutes in the first, second, and third half-year, respectively. The average estimated blood loss was 170 mL, 160 mL, and 180 mL in the first, second, and third half-year, respectively. In the same period, the average volume of tumors treated with OPN was 3.7 cm, 3.9 cm, and 5.7 cm respectively in the first, second, and third half-year.

Conclusions

We have observed a gradual extension of the indications for NSS. The systematic application of robotic surgery has allowed for the treatment of even more complex cases with relatively low learning curve. OPN has therefore become a technique that should be reserved for more complex cases.
Rhetoric, Dialectic, and Logic as Related to Argument
Authors: Blair J. Anthony
Published: May 2012

This article challenges the view that rhetoric, dialectic and logic are three perspectives on argument, relating respectively to its process, its procedure, and its product. It also questions the view that rhetorical arguments represent a distinctive type. It suggests that, as related to argument, rhetoric is the theory of arguments in speeches, dialectics the theory of arguments in conversations, and logic the theory of good reasoning in each.
Low-Dose Chemotherapy with Insulin (Insulin Potentiation Therapy) in Combination with Hormone Therapy for Treatment of Castration-Resistant Prostate Cancer
Authors: Damyanov Christo , Gerasimova Desislava , Maslev Ivan , Gavrilov Veselin
Published: May 2012

Purpose. To evaluate the results and quality of life of patients with resistant of castration-resistant tumors previously treated with Insulin-potentiation therapy (IPT) combined with hormone therapy. Materials and methods. Sixteen patients with metastasis prostate tumors after bilateral castration, androgenic blockade, and progression of the disease were observed during the study. The patients were divided into two groups: group A consisting of 8 patients treated with low-dose chemotherapy Epirubicin, Vinblastine, and Cyclophosphamide combined with LHRH agonist and group B consisting of another 8 patients treated with low-dose chemotherapy Docetaxel combined with LHRH agonist. Results. The overall (groups A and B) results concerning PSA after the sixth IPT show partial effect in 8 out of 16 (50%) patients, stabilization in 4 out of 16 (25%), and progression in 4 out of 16 (25%). The median survival for all treated patients is 11,7 months (range 3–30 months). During the treatment no significant side effects were observed, and no lethal cases occurred. Conclusion. In spite of the small number of the treated patients with castration-resistant prostate tumors, the preliminary results are promising and this gives us hope and expectations for future serious multicenter research over the possibilities for routine implementation of IPTLD.
A Nonaxisymmetric Solution of Einstein’s Equations Featuring Pure Radiation from a Rotating Source
Authors: Davidson William
Published: May 2012

A special nonaxisymmetric solution of Einstein’s equations is derived, representing pure radiation from a rotating isolated source. The spacetime is assumed to be algebraically special having a multiple null eigenvector of the Weyl tensor forming a geodesic, shear-free, diverging, and twisting congruence k. Employing a complex null tetrad involving the vector k, the Ricci tensor, density of the radiation, divergence, and twist are calculated for the derived metric. A particular (nonaxisymmetric) subcase is shown to be flat at infinity and to contain the axisymmetric radiating Kerr metric, derived by Kramer and separately by Vaidya and Patel, as a special case. The spacetime is of Petrov type II and without Killing vectors.
Electrical Conductivity Testing as Applied to the Assessment of Freshly Collected Kielmeyera coriacea Mart. Seeds
Authors: Ramos Kennya Mara Oliveira , Matos Juliana M. M. , Martins Rosana C. C. , Martins Ildeu S.
Published: May 2012

Assessment of seed vigor has long been an important tool of seed quality control programs. The conductivity test is a promising method for assessment of seed vigor, but proper protocols for its execution have yet to be established. The objective of this study was to assess the efficiency of electrical conductivity (EC) testing as a means of assessing the viability of freshly collected Kielmeyera Coriacea Mart. seeds. The test was performed on individual seeds rather than in a bulk configuration. Seeds were soaked for different periods (30 min, 90 min, 120 min., 180 min, and 240 min) at a constant temperature of 25°C. Conductivity was then measured with a benchtop EC meter.
Influence of Calcium Ions on Cell Survival and Proliferation in the Context of an Alginate Hydrogel
Authors: Cao N. , Chen X. B. , Schreyer D. J.
Published: May 2012

One goal of biofabrication is to incorporate living cells into artificial scaffolds in order to repair damaged tissues or organs. Although there are many studies on various biofabrication techniques, the maintenance of cell viability during the biofabrication process and cell proliferation after the process is still a challenging issue. Construction of scaffolds using hydrogels composed of natural materials can avoid exposure of cells to harsh chemicals or temperature extremes but can still entail exposure to non-physiological conditions, causing cell damage or even death. This paper presents an experimental investigation into the influence on Schwann cell survival and proliferation of calcium used for ionic crosslinking of alginate hydrogel during the biofabrication process. The experimental results obtained show the viability and proliferation capacity of cells, either suspended in cell culture medium or encapsulated in hydrogel, and vary with the calcium concentration and the time period of cells exposed to the calcium environment. The experimental results also show the alginate concentration and cell density, that have profound influence on cell survival and proliferation, and solution viscosity as well. This study suggests the incorporation of living cells in calcium-crosslinked hydrogel in the biofabrication process can be regulated for controlled cell survival and proliferation.
Wet Synthesis of Monodisperse Cobalt Oxide Nanoparticles
Authors: Athar Taimur , Hakeem Abdul , Topnani Neha , Hashmi Ameed
Published: May 2012

Ultrafine and monodispersable colloidal cobalt oxide nanoparticles were successfully synthesized quantitatively via soft chemical approach with controlled particle size and microstructural properties for their use in technological applications. The particle size, shape, and other microstructural properties are directly influenced by their reaction conditions. The FT-IR studies give information for phase purity, and ultraviolet absorption spectroscopy helps to study the optical properties. Thermal analysis gives the information about thermal stability. With the help of X-ray diffraction pattern, the size of the particle was calculated. An electron microscope studies help in morphological characterization, and Brunauer-Emmett-Teller method gives information about surface area. Cobalt oxide nanoparticle tends to orient itself with its narrow size distribution having a crystal size around 50 nm.
Tissue Reactions to Various Suture Materials Used in Oral Surgical Interventions
Authors: Javed Fawad , Al-Askar Mansour , Almas Khalid , Romanos Georgios E. , Al-Hezaimi Khalid
Published: May 2012

A variety of suture materials are available for primary wound closure following oral surgical procedures. The aim was to review the tissue reactions to the various suture materials used in oral surgical interventions. Databases were searched using the following keywords: cotton, nylon, polyglecaprone 25, polytetrafluoroethylene (ePTFE), Polyglactin 910, polyglycolic acid (PGA), polylactic acid, silk, surgery, suture, and tissue reaction. Articles published only in English language were included. Seventeen studies were included. Two studies reported that polyglecaprone 25 had positive effects on wound-healing as compared to silk. Six studies reported that silk elicits more intense tissue inflammatory response and delayed wound healing as compared to other suture materials (including ePTFE, polyglecaprone-25, PGA, and nylon). Polyglactin 910 sutures were associated with the development of stitch abscess in one clinical study. Eight studies reported that tissue reactions are minimal with nylon sutures. Tissue reactions to suture materials used for oral surgical interventions may vary depending on the surface properties and bacterial adherence properties of the material.
Abnormal Movements of Japanese Infants following Treatment with Midazolam in a Neonatal Intensive Care Unit: Incidence and Risk Factors
Authors: Irikura Mitsuru , Minami Eri , Ishitsuka Yoichi , Kawase Akihiko , Kondo Yuichi , Irie Tetsumi
Published: May 2012

Background. This study was conducted to investigate the incidence of, and factors associated with, myoclonus-like abnormal movements of Japanese infants following treatment with midazolam in a neonatal intensive care unit (NICU).Methods. We retrospectively investigated abnormal movements and associated risk factors in Japanese infants (less than 1 year old) who received continuous intravenous midazolam treatment in the NICU of the Neonatal Medical Center, Kumamoto City Hospital, Japan, between April 2007 and March 2009.Results. The study included 94 infants who received 119 sessions of midazolam treatment in total. Nine infants (9.6%) developed abnormal movements attributable to midazolam. These nine patients had a significantly lower gestational age at birth, a significantly lower number of weeks after conception at the start of midazolam treatment, and significantly lower body weight compared with patients free of abnormal movements. Logistic regression analysis revealed neonatal asphyxia as a factor associated with an elevated risk of abnormal movements ().Conclusion. The incidence of abnormal movements after midazolam treatment was about 9.6% among the Japanese NICU infants. This result suggests that neonatal asphyxia may be involved in the onset of abnormal movements in infants treated with midazolam.
Natural Products: A Minefield of Biomaterials
Authors: Ige Oladeji O. , Umoru Lasisi E. , Aribo Sunday
Published: May 2012

The development of natural biomaterials is not regarded as a new area of science, but has existed for centuries. The use of natural products as a biomaterial is currently undergoing a renaissance in the biomedical field. The major limitations of natural biomaterials are due to the immunogenic response that can occur following implantation and the lot-to-lot variability in molecular structure associated with animal sourcing. The chemical stability and biocompatibility of natural products in the body greatly accounts for their utilization in recent times. The paper succinctly defines biomaterials in terms of natural products and also that natural products as materials in biomedical fields are considerably versatile and promising. The various types of natural products and forms of biomaterials are highlighted. Three main areas of applications of natural products as materials in medicine are described, namely, wound management products, drug delivery systems, and tissue engineering. This paper presents a brief history of natural products as biomaterials, various types of natural biomaterials, properties, demand and economic importance, and the area of application of natural biomaterials in recent times.
Microstructures of YSZ and CGO Thin Films Deposited by Spray Pyrolysis: Influence of Processing Parameters on the Porosity
Authors: Scherrer Barbara , Martynczuk Julia , Galinski Henning , Grolig Jan G. , Binder Selmar , Bieberle‐Hütter Anja , Rupp Jennifer L. M. , Prestat Michel , Gauckler Ludwig J.
Published: May 2012

Microstructures of yttria‐stabilized zirconia (YSZ) thin films deposited by spray pyrolysis at 370 °C on sapphire are investigated. The as‐deposited films are predominantly amorphous and crystallize upon heating at temperatures above 370 °C, developing grains in the range of 5 nm to several 100 nm. During post‐deposition heat treatment up to 800 °C, ∼ 50 vol% porosity develops in the center of the films with gradients towards almost dense interfaces to the air and substrate. The reason for this porosity is the decomposition of residues from the precursor and the free volume liberated due to crystallization. Dense YSZ thin films consisting of one monolayer of grains are obtained with annealing temperatures exceeding 1200 °C. In gadolinium‐doped‐ceria (CGO) thin films similar microstructures and porosity are found after low‐temperature heat treatments indicating that the precursor residues due to the deposition method are the main cause of the porosity. Grain growth stagnation in annealed thin films is observed in both the YSZ and in CGO thin films. Stagnating grain growth in the thin films is rather caused by reduced grain boundary mobility, here predominately due to a “secondary phase”, i.e., pores, than to other effects. The stagnation ceases at higher annealing temperatures after densification has taken place.
LbL‐coated microcapsules as systems for encapsulation of optical brightening agent
Authors: Tripathy Jasaswini , Raichur Ashok M.
Published: May 2012

We report the encapsulation of optical brightening agent (OBA) into hollow microcapsules prepared by the controlled Layer‐ by‐Layer (LbL) self‐assembly process, achieved by the sequential adsorption of oppositely charged polyelectrolytes using negatively charged silica template. Loading takes place by spontaneous deposition method which was proved by confocal laser scanning microscopy (CLSM) using rhodamine 6G (Rd6G) as a fluorescent probe. The loading of the OBA into the microcapsules was found to be dependent on the feeding concentration, pH of the medium, and loading temperature. The encapsulation efficiency of OBA decreased on increasing feeding concentration. Maximum loading was observed at pH 4 and amount of OBA loaded decreased with increase in pH. The loaded OBA was released in a sustained manner for 8 h. No degradation of the OBA was observed during the process of encapsulation and release. Polyelectrolyte capsules potentially offer an innovative way of encapsulating large amounts of active materials for a variety of applications. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effects of calcium carbonate and compounding sequence on the phase morphology and properties of maleic anhydride‐grafted polypropylene compatibilized polyamide 6/polypropylene blend
Authors: Wang Li , Ling Xue‐Liang , Shi Chen , Guo Zhao‐Xia , Yu Jian
Published: May 2012

Effects of calcium carbonate (CaCO3) and compounding sequence on the phase morphology of maleic anhydride‐grafted polypropylene (MAPP) compatibilized polyamide 6 (PA6)/polypropylene (PP) blend were investigated. The morphology in the subskin and core regions of injection molded specimen was observed using scanning electron microscopy, which shows great changes due to the incorporation of CaCO3. With the addition of CaCO3 (25 phr), oriented “ginger‐like” network (directly mixing) or loose elongated network (mixing PA6, PP, and MAPP with premixed PA6/CaCO3 masterbatch) of PP phase is formed in the core region, instead of spherical dispersed PP domains for unfilled blend. The distribution of CaCO3 in PA6 and PP phases was determined by selectively dissolving PA6 phase and thermogravimetric analysis of PP phase. A possible mechanism is proposed based on the morphology evolution process to interpret the morphological differences. The mechanical properties and heat distortion temperature of the materials were tested and correlated with the morphology formed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis and properties of crosslinked poly(arylene ether nitriles) containing pendant phthalonitrile
Authors: Yang Jian , Yang Xulin , Zhan Yingqing , Zou Yanke , Zhao Rui , Liu Xiaobo
Published: May 2012

In this study, poly(arylene ether nitriles) containing pendant carboxyl groups (PEN‐COOH) was first synthesized via nucleophilic aromatic substitution reaction from phenolphthalein, hydroquinone and 2,6‐dicholorobenzonitrile. Then, poly(arylene ether nitriles) with pendant phthalonitrile groups (PEN‐CN) was obtained via the Yamazaki–Higashi phosphorylation route from 4‐(4‐aminophenoxy)phthalonitrile (APN) with PEN‐COOH in the presence of CaCl2, thus the phthalonitrile as pendant groups in PEN‐CN were easily crosslinked by further thermal treatment. The effect of crosslinking density on the thermal stabilities, dielectric properties and water absorption of the PEN‐CNs was investigated. These results showed that the Tg of PEN‐CN was improved from 182 to 213°C, dielectric constant (ε) was increased from 3.1 to 3.9, and dielectric loss (tan δ) was decreased from 0.090 to 0.013 at 1 kHz. The water absorption of PEN‐CNs after thermal crosslinking was <1.01 wt %, which showed excellent water resisting property. Therefore, this kind of poly(arylene ether nitriles) containing pendant phthalonitrile could be a good candidate as matrix resins for high‐performance polymeric materials. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Development of thin layer polymers to concentrate and detect aquatic contaminants
Authors: Lyons Rebecca A. , Hassett John P. , Flach Anna M. , Cabasso Israel
Published: May 2012

Poly(dimethylsiloxane) (PDMS) and a poly(DMS‐styrene) block copolymer were compared as extraction and optical detection media for hydrophobic compounds in water and water/ethanol solutions. Partitioning to both polymers increased exponentially with increased percent water in ethanol. Partition coefficients to the copolymer were 10–30‐fold higher than to PDMS. Ultraviolet absorbance spectra of pyrene showed a 4‐nm red‐shift in copolymer versus PDMS, providing evidence of π–π interactions, accounting for greater partitioning. The extinction coefficient coefficient of pyrene at 334 nm was twice as high in the copolymer as in PDMS. The combination of higher affinity for polycyclic aromatic hydrocarbons with higher absorbance make poly(DMS‐styrene) copolymers promising material for extraction and in situ detection of hydrophobic aromatic compounds in water. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Stability Analysis of a Class of Neutral Type Systems in a Critical Case Without Restriction on the Principal Neutral Term
Authors: Quan Quan , Cai Kai‐Yuan
Published: May 2012

This study focuses mainly on the stability of a class of linear neutral systems in a critical case, that is, where the spectral radius of the principal neutral term (matrix H in this paper) is equal to 1. It is difficult to determine the stability of such systems via existing methods. In this study, a sufficient stability criterion for the critical case without restrictions on the principal neutral term is given in terms of the existence of solutions to a linear matrix inequality.
Collaborater for a Car‐Like Vehicle Driven by a User with Visual Inattention
Authors: Chavez D. , Slawinski E. , Mut V.
Published: May 2012

This paper proposes a control system applied to a car‐like vehicle driven by a user. The controller is designed to mitigate the negative effects produced by possible visual distractions of this user. In addition, the paper proposes to evaluate the user's visual distraction, defining a vector that has two components: one with respect to the path and the other with respect to the obstacles. These elements can be computed on‐line and are associated with two time delays that produce a similar effect of instability on the motion of the vehicle. The proposed scheme considers the distraction in the design through such delays. Finally, experiments using a car simulator are carried out
Wellenbrechen an Offshore Tripod‐Gründungen –Versuche und Simulationen im Vergleich zu Richtlinien
Authors: Hildebrandt Arndt , Schlurmann Torsten
Published: May 2012

Mehrere tausend Windanlagen werden für die Realisierung der politischen Ziele bezüglich der Nutzung von Offshore Windenergieanlagen (OWEA) als erneuerbare Energieform benötigt. Für die Serienproduktion lässt sich eine Struktur möglichst wirtschaftlich entwerfen, je genauer die Lastmodellierung die realen Einwirkungen abbildet; dabei sind die Lastannahmen für brechende Wellen auf Grund ihrer komplexen Geometrie mit diversen Unsicherheiten verbunden, weshalb im Forschungsprojekt “GIGAWIND alpha ventus ‐ TP 1” innerhalb des Forschungsverbundes “Research at Alpha VEntus” (RAVE) u.a. Forschungsschwerpunkten auch brechende Wellen an Gründungsstrukturen untersucht wurden. Hierfür wurden im “Großen Wellenkanal” am Forschungszentrum Küste (FZK, Hannover) Modellversuche an einem Tripod im Maßstab 1:12 durchgeführt. An der Gründungsstruktur wurde unter anderem die räumliche und zeitliche Druckbelastung infolge brechender Wellen erfasst. Im Anschluss wurde mit der Datengrundlage ein dreidimensionales numerisches Strömungsmodell erstellt, das neben der Belastungsanalyse auch zusätzliche Erkenntnisse über die Wellenkinematik und die hydrodynamische Umströmung der zylinderartigen Struktur liefert.

In dem folgenden Artikel werden Ergebnisse der physikalischen und numerischen Modelle beschrieben und einander gegenüber gestellt. Abschließend erfolgt ein Vergleich mit dem Lastansatz nach DIN EN 61400‐3 für die Auslegung von Offshore Windenergieanlagen.

Breaking Wave Impact on Offshore Tripod Structures – Comparison of large scale Experiments, CFD Simulations, and DIN Recommended Practice

Coastal and near shore areas offer a large potential for offshore wind energy production due to strong and steady wind conditions. Thousands of offshore wind energy converters are projected for mass production within the next years. Detailed understanding of the extreme, dynamic wave loads on offshore structures is essential for an efficient design. The impact on structures is a complex process and further studies are required for more detailed load assessments, which is why breaking wave loads were investigated by the research project “GIGAWIND alpha ventus – Subproject 1” within the network “Research at Alpha VEntus” (RAVE). Large scale laboratory tests (1:12) with breaking waves have been carried out at the Large Wave Flume of the “Forschungszentrum Küste” (FZK, Hanover) to reveal more detailed insights on the impact area, duration and development of the wave induced momentum, and intensity of pressures. In addition, local pressures calculated by a three‐dimensional numerical impact simulation are compared to the Large Wave Flume experiments. Slamming coefficients have been derived from the physical model tests and CFD simulations for the comparison to load calculations based on guidelines.
Nachbildung der Hydroabrasionsbeanspruchung im Laborversuch
Authors: Mechtcherine Viktor , Bellmann Claudia , Helbig Ulf , Horlacher Hans‐B. , Stamm Jürgen
Published: May 2012

Von feststoffhaltigem Wasser überströmte Betonoberflächen von Wasserbauwerken zeigen nach entsprechender Beaufschlagungsdauer einen erheblichen Oberflächenverschleiß. Durch die bewegten Feststoffe wird in die Betonoberflächen kinetische Energie eingetragen, die zu einer oberflächennahen Gefügeschädigung in Form von Mikrorissen führt. Um eine Aussage zum vorhandenen Abrasionswiderstand bzw. zur Restlebensdauer von abrasionsbelasteten Betonoberflächen an Wasserbauwerken treffen zu können, ist eine genaue Kenntnis der Zusammenhänge zwischen den Abrasionsvorgängen an der Betonoberfläche und der gleichzeitig und zuvor auf mikroskopischer Ebene stattfindenden Degradation des Betongefüges in der abrasiv belasteten Schicht erforderlich. In der vorliegenden Studie wurden neben den Experimenten zur Hydroabrasion eingehende Untersuchungen zur Werkstoffcharakterisierung durchgeführt, mit denen Änderungen der Gefügestruktur des Betons unter besonderer Berücksichtigung der Rissentwicklung erfasst werden konnten. In diesem ersten Teil des Aufsatzes werden die experimentellen Ergebnisse vorgestellt und diskutiert. Auf Basis der gewonnenen Erkenntnisse und Daten wurde anschließend ein vorhandenes Abrasionsprognosemodell erweitert, welches nun eine quantitative Prognose des Oberflächenverschleißes ermöglicht. Dieses Modell wird im zweiten Teil des Artikels präsentiert.

Simulation of hydro‐abrasion loading in the laboratory: Part 1 – Experimental investigation into the deterioration of concrete

The concrete surfaces of hydraulic structures can deteriorate severely when continuously or frequently overflowed by water containing solid particles; this process is called hydro‐abrasion. Kinetic energy introduced to the concrete surface by moving solid particles leads most probably to near‐surface damage of the concrete in the form of micro‐cracks. In predicting the abrasion resistance and the remaining lifetime of concrete structures subjected to hydro‐abrasion, a sound knowledge of the mechanisms leading to the wear of concrete on different levels of observation is needed. Besides the hydro‐abrasion tests morphological analysis of the concrete microstructure was performed in order to attain better understanding of the wear mechanisms. In this first part of the paper the experimental results are presented and discussed. Based on the attained insights and data, an existing abrasion prognosis model for abrasion was extended, which now allows for a quantitative prediction of the surface wear. This model will be described in the second part of the article.
Bauwerksinspektion an Verkehrswasserbauwerken
Authors: Kloé Katrin , Bödefeld Jörg
Published: May 2012

Die Verantwortung für die Bundeswasserstraßen und die zugehörigen Anlagen hat der Bund mit Artikel 89 des Grundgesetzes an die Wasser‐ und Schifffahrtsverwaltung des Bundes (WSV) delegiert, die dem Bundesministerium für Verkehr, Bau und Stadtentwicklung (BMVBS) nachgeordnet ist. In den vergangenen Jahren hat die WSV zusammen mit dem BMVBS und der Bundesanstalt für Wasserbau (BAW) die Abläufe der Bauwerksinspektion an den Anlagen, die zugehörigen Regelwerke sowie die unterstützenden Instrumente umfangreich überarbeitet und modernisiert. Dieser Beitrag gibt einen Überblick über die Neuerungen in der Bauwerksinspektion.

Inspections for waterway infrastructure

By the constitution of German, the responsibility for the German waterways is delegated to the Federal Waterway Administration (WSV), which is part of the Ministry of Transport, Mobility and Urban Development (BMVBS). In recent years the WSV together with the BMVBS and the Federal Waterways Engineering and Research Institute (BAW) have received and updated the operation, the regulations and supporting tools for the inspection at the waterway constructions. The article gives an overview of the innovation in the process of inspection.
Tauchwände als Wellenbrecher
Authors: Frese Marianne , Bleck Matthias , Schöner Michael
Published: May 2012

Tauchwände sind eine gängige Methode, um Treibgut von der Wasseroberfläche abzuschöpfen und so z.?B. Kraftwerkseinläufe oder Kläranlagenteile zu schützen. Die Anwendung als Wellenbrecher im Hafenbau und Küstenschutz erfolgt relativ selten, weshalb die Bemessung in den gängigen Regelwerken so gut wie gar nicht behandelt wird. Da bei dem Bau von Wellenbrechern selten nach vollständigem Schutz verlangt wird, kann eine Tauchwand eine kostengünstigere Alternative darstellen. Der Vorteil dieses Wellenbrechertyps liegt in der Erhaltung der hydraulischen Anbindung des geschützten Bereichs. Dies kann z.?B. aufgrund von ökologischen Anforderungen gewünscht sein. Durch den Erhalt des Wasseraustauschs wird der sohlnahe Sedimenttransport weniger gestört als bei herkömmlichen Wellenbrechern, was nachteilige Auswirkungen auf die Morphologie reduziert. Die Schwierigkeit bei Anwendung von Tauchwandwellenbrecher liegt in der Abschätzung der hydraulischen Wirksamkeit und der hydraulischen Belastung infolge Wellenangriffs. Der Artikel berichtet hierzu von Erfahrungen aus aktuellen Projekten und ergänzt diese um weitergehende Untersuchungen zum Verhalten dieser Bauwerke als Küstenschutzelement.

Scum boards as breakwaters – experiences and latest developments

Scum boards are a usual method to skim floating objects (e.g. debris) of the water surface e.g. to protect power plant intakes or water treatment plants. The application as a breakwater for coastal protection or port constructions is quite seldom. Thus the design of scum boards as breakwaters (baffle breakwater) is mostly not included in standard design manuals. Nevertheless as a total blockage of waves and currents is not needed for many breakwater constructions baffle breakwaters can be a cost efficient alternative as less material is required especially for large water depths. The up to a certain degree protected area is still connected to the surrounding water body which may be required e.g. for ecological reasons (water circulation and quality). In addition the bed load sediment transport will not be interrupted which will reduce the morphological impact of the breakwater (lee erosion). The difficulties in the application of baffle breakwaters are the assessment of the hydraulic function and loads especially due to wave attack. The present article describes experiences from recent projects and gives an overview about the existing design rules for baffle breakwaters.
Hafenentwicklung in Litauen
Authors: Retzlaff Torsten
Published: May 2012

Der folgende Bericht geht auf die erfolgten Planungen zur zukünftigen Entwicklung und Erweiterung des Seehafens Klaipeda in Litauen ein. Eine nachhaltige Entwicklung des vorhandenen Hafens sowie dessen Erweiterung ist notwendig, um auch zukünftig den Herausforderungen des Welthandels und der stetig wachsenden Warenströme gerecht zu werden. Im Fokus der Hafenentwicklungsplanung stehen die Weiterentwicklung der bestehenden Hafeninfra‐ und Hafensuprastruktur sowie Vorschläge zur Verbesserung der allgemeinen Wettbewerbsfähigkeit und der Hafenverwaltung. Eine Herausforderung stellen die begrenzten Möglichkeiten einer territorialen Entwicklung des Hafens aufgrund eines angrenzenden Stadt‐ und Naturschutzgebietes dar. Neben den Maßnahmen zur Optimierung des bestehenden Hafengeländes wurden verschiedene Standorte an der Ostseeküste Litauens für eine externe Hafenentwicklung bewertet. Für die favorisierten Varianten waren die technischen Entwicklungspläne zu erstellen, eine finanzökonomische Bewertung durchzuführen sowie die notwendigen umweltrechtlichen Genehmigungen einzuholen.

Port development in Lituania – Projecting of the sea port Klaipeda

The following report is concerned with the implemented planning works regarding the future development and extension of Klaipeda Sea Port. A sustainable development of the existing port facilities as well as its extension will be required to meet the demanding and highly competitive challenges of global trade and the growing flow of commodities. This port development project comprises the aspects of the development of the existing port infrastructure and superstructure as well as suggestions for the improvement of the general competitiveness and the port administration. The possibilities of the territorial development of Klaipeda Port are limited to the adjacent city area as well as the adjacent natural protection area. Besides the optimization of the existing port facilities, various port locations at the Baltic Sea coast of Lithuania had to be evaluated concerning the external port development. For the most suitable alternatives the technical development plans had to be developed, the financial‐economic evaluation had to be implemented as well as the required environmental approvals had to be obtained.