bluuebunny/crossref_metadata_2025 huggingface dataset:
Análisis de métodos para evaluar el refuerzo a esfuerzo cortante con CFRP en vigas de hormigón armado
Authors: Parra C. , Martínez-Conesa E. , Valcuende M. , Garrido A.
Published: June 2012

En este trabajo de investigación se comparan diferentes modelos de cálculo de refuerzo a esfuerzo cortante mediante polímeros reforzados con fibras de carbono (CFRP) clasificados según el modo de fallo. En el diseño del refuerzo se tiene en cuenta la modificación del comportamiento de la viga por el refuerzo. Los estudios muestran que siempre que sea posible, la dirección principal de las fibras debe ser perpendicular a las fisuras de cortante. La contribución del refuerzo a la resistencia a cortante de la viga depende de los estribos de acero existentes en la viga original. Cuando aumenta el espesor del refuerzo la resistencia a cortante de la viga se incrementa. Esta relación tiende a ser lineal cuando la viga no está fisurada. Por último indicar que tanto el ángulo de inclinación de las fisuras, como el cortante resistido por el refuerzo, dependen del ángulo de inclinación de las fibras.
Successful Integration of Informal Learning in Engineering Education
Authors: Grant Lynroy , Abu-aisheh Akram Ahmad
Published: June 2012

Abstractâ?? Research suggests that an emerging environment of ubiquitous information technology affords seamless movement between formal learning, informal learning, and the workplace. This paper reviews research data from one successful teaching and learning methodology that leverages seamless movements between informal and formal learning in engineering education. The research is an ongoing pilot study at the University of Hartford using data from selected technical mathematics and communication electronics courses. The research data suggests that clearly defined academic jurisdictions have a positive correlation with successful integration of formal learning, informal learning, and the workplace. However, themes from the data also suggest that crossing academic boundaries involves more than technology issues and could raise the specter of unintended social-dramas. One theme suggests that, in a seamless environment without clearly defined academic jurisdictions, opportunities for collaboration could be misinterpreted as encroachments. To mitigate issues of competing jurisdictional interests this study employs Learner Agent Objects (LAO) individual portfolios. LAO portfolios are collections of evidence-based artifacts representing a learner's academic experience that independently moves with the learner as data network nodes between jurisdictions in engineering education and the workplace.
The Learning Continuum: formal and informal learning experiences – enabling learning and creation of new knowledge in an organization.
Authors: Sinha Amitabh
Published: June 2012

Over the years, there has been a significant shift in the approach towards â??learningâ?? in an organization. The focus of learning is no more limited to only the formal training mediums, such as classroom interventions and e-learning programs. The shift in learning paradigm is more towards the creation of new learning solution that provides formal and informal learning, information and collaboration â?? thereby enabling the formation of a â??personal learning environment.â?? Now, there is a shift from â??content focusâ?? to â??learner focusâ?? education. This paper will suggest the appropriate use of technologies and processes to create a rich learning environment that includes a broad array of instructions, information resources, and collaborative solutions. The paper will also focus on the areas or situations where the new learning environment can be applied and the ways in which an organization can leverage the full range of its learning continuum.
Opening a M. Sc. in Electrical Engineering for non-traditional Students
Authors: Müller Anja Lina , Schwarzbacher Andreas , Hoppe Bernhard
Published: June 2012

This paper will discuss why and how the University of Applied Sciences, Darmstadt/Germany will identify core competences of bachelorâ??s degrees in Electronic Engineering and develop specially tailored life-long learning programmes for non-traditional students. These programmes will enable highly qualified master craftsmen, solely educated to the level of master craftsmen, to successfully participate in the existing Master of Science in Electronic Engineering programme. Furthermore, this paper will present the initial results obtained from a pilot project group.
Alternating Magnetic Field Responses of Magnetic Fluid Drop Adsorbed to a Small Permanent Magnet
Authors: Sudo Seiichi , Asano Daisaku , Takana Hidemasa , Nishiyama Hideya
Published: June 2012

Experimental studies of the behavior of magnetic fluid drop under the effect of an external alternating magnetic field were performed using a high speed digital video camera system. A small permanent magnet was immersed in magnetic fluid drop, and it was fixed with an aluminum bar. The surface of magnetic fluid responded to the external magnetic field sensitively. The free surface of the magnetic fluid drop responded to the external alternating field in elongation and contraction along the direction of the field. The capillary magnetic fluid jet was produced at the certain external magnetic field condition.
Vibration Characteristics of Magnetic Fluid Droplet Adsorbed to Magnetized Needlepoint in Alternating Magnetic Field
Authors: Inomata Sota , Sudo Seiichi , Takana Hidemasa , Nishiyama Hideya
Published: June 2012

The dynamic behavior of a magnetic fluid droplet adsorbed to magnetized needlepoint in alternating magnetic field was studied with a high speed video camera system. The directions of alternating magnetic field were parallel and opposite to static magnetic field of magnetized needlepoint. It was found that the surface of magnetic fluid droplet responds to the external magnetic field in elongation and contraction. The frequency of magnetic fluid droplet oscillation was exactly same of the external magnetic field. The shape and instability oscillations of the magnetic fluid droplet were revealed experimentally.
Development of Miniature Transducer-Type Magnetic Property Measurement for Motor Stator Core
Authors: Nagata Shoichiro , Kido Yukihito , Enokizono Masato
Published: June 2012

In this paper, we present a new magnetic property measurement system. We developed a miniature transducer, with a 16-mm2 footprint, for measuring the local magnetic properties of a motor stator core. The construction of the transducer and measurement system is proposed, and experimental results show the validity of the measurements.
A Three-Element Handheld Mobile Communication Antenna for Desired Signal Reception and Reflected Signal Cancellation
Authors: Hoole Paul Ratnamahilan Polycarp , Raheem Lwin Maw Abdul , Harikrishnan Ramiah , Jeevan Kanesan , Hoole Samuel Ratnajeevan Herbert
Published: June 2012

Abstract. Space diversity, where antennas are separated in space at the receiver, is considered one of the most effective ways of eliminating unwanted signals in order to maximize the signal to noise ratio of the desired signal. Moreover it may be used to receive a signal that has gone through less fading when the direct path signal may have undergone deep fade. In this paper we use analytical electromagnetic solutions for the radiated signals to implement antenna space diversity on small handheld receiver units of mobile stations. While using the standard time difference of arrival method to obtain a first approximation of the mobile station position, the electromagnetic model is used to determine a more accurate position of the mobile station. The performance of this method with a multi-element mobile station antenna is shown to give good position estimation in the presence of various of kinds noise. A three element mobile station receiver is for the first time reported to be able simultaneously to null a deeply faded signal in the Rayleigh fading environment, and maximize the signal strength. It is shown that a three element antenna may be used to eliminate an undesired signal, while it may maximize the reception of the desired signal. The transmitter does not require a training sequence, as in the case of an equalizer, since the entire signal processing of the electromagnetic signal is done at the mobile receiver.
Design Optimization Procedure for Amorphous Core Distribution Transformers
Authors: Amoiralis Eleftherios I. , Tsili Marina A. , Kladas Antonios
Published: June 2012

The paper presents a design optimization procedure appropriate for distribution transformers with amorphous alloy cores. Several considerations and the main differences from the design practice of conventional transformers are presented and discussed in detail. Moreover, comparison of results present the significant benefit in the transformer energy efficiency by the selection of amorphous alloy core, despite its initial higher installation cost.
Benchmark Solutions for Magnetic Fields in the Presence of Two Superconducting Spheres
Authors: Ciric Ioan R. , Kotuwage Kumara S.C.M.
Published: June 2012

A complete solution is presented for the boundary value problem of two perfect conductor spheres in a uniform magnetic field of arbitrary orientation. Expressions are given for the scalar magnetic potential and for the field intensity. They can readily be applied for calculating the forces between the spheres. Benchmark numerical results of specified accuracy are generated, which are also useful for validating various approximate numerical methods.
Study on Improvement of Transmission Torque for a Surface Permanent Magnet Type Magnetic Gear
Authors: Oka Masaru , Todaka Takashi , Enokizono Masato , Nagaya Kousuke , Fujita Tomoyuki
Published: June 2012

Magnetic gears are a force transmitter consisting of permanent magnets. The mechanical input can be transmitted to an output shaft without contact by magnetic forces. The magnetic gears are not worn out because there is no friction. As a result, the running costs such as the maintenance fee can be suppressed and the resources can be saved. However, the transmission torques of the conventional magnetic gears, which have so far been developed, are very low. Besides, new structure models designed for high torque density need a lot of permanent magnets and multi-pole constructions. Those structures are complex and the manufacturing is difficult. In this research, we applied a flux concentration type surface permanent magnet arrangement to a surface permanent magnet type magnetic gear in order to improve the transmission torque and to reduce the amount of permanent magnets. The magnetic flux distribution, the gap flux density and the transmission torque of the developed new models are numerically analyzed by using the two-dimensional finite element method. In this paper, a permanent magnet structure optimized to reduce its amount and influence of the flux concentration type surface permanent magnet arrangement on the gap flux density distribution and transmission torque are reported.
Measuring AC Losses and Critical Current of High Pressure Synthesized MgB2 Bulk Rings by the Transformer Method
Authors: Meerovich Victor , Sokolovsky Vladimir , Prikhna Tatiana , Gawalek Wolfgang
Published: June 2012

The results of experimental study of the critical current and AC losses in high pressure-synthesized MgB2bulk superconductors are presented. The method is based on the use of the transformer configuration and suitable for samples in the form of hollow superconducting cylinders and rings. It was shown that the critical current measured by the transformer method is an order of magnitude lower than the value given by the magnetization technique. The obtained dependencies of the losses on current and frequency reveal the deviations from the critical state model behavior and reflect structural peculiarities of the investigated MgB2samples.
Reduction of the Distortion Current Factor of the Current Drawn by the Electromagnetic Vibrators Supplied at Variable Frequency
Authors: Balan Horia , Buzdugan M.I. , Chiorean C. , Karaissas P.
Published: June 2012

The paper presents a possibility of supplying the electromagnetic vibrators with variable frequency voltage. Two types of modulated controls of the inverter’s commutation angle are presented. The theoretical analysis allows the study of the variable element influence on the distortion factor and of the harmonic content generated by the vibrator. The authors present an experimental validation of the presented theory, using the harmonic measurement of the distorted waveform. The harmonic response is useful in quantifying the performances of the harmonic filters to be introduced between the nonlinear consumer and the power grid and on the other hand the electromagnetic interference determined to other customers connected to the power grid.
Overview of the Alternative Topologies of Linear Generators in Wave Energy Conversion Systems
Authors: Kakosimos Panagiotis E. , Tsampouris Evangelos M. , Kimoulakis Nikolaos M. , Kladas Antonios
Published: June 2012

Several operation principles and generator types have been developed because of the growing interest for the wave energy conversion systems (WECSs). A WECS is demanded to be more efficient so that the overview of the already developed systems is necessary. An overview of the different operation principles and the various linear generator types is presented analyzing the advantages and the disadvantages. Finally, a complete scheme gathering the most vital characteristics is introduced.
Reverse Engineering Legacy Finite Element Code
Authors: Hoole Samuel Ratnajeevan Herbert , Arudchelvam Thiruchelvam , Wijayakulasooriya Janaka
Published: June 2012

The development of code for finite elements-based field computation has been going on at a pace since the 1970s, yielding code that was not put through the software lifecycle – where code is developed through a sequential process of requirements elicitation from the user/client to design, analysis, implementation and testing and release and maintenance. As a result, today we have legacy code running into millions of lines, implemented without planning and not using proper state-of-the-art software design tools. It is necessary to redo this code to exploit new object oriented facilities and make corrections or run on the web with Java. Object oriented code’s principal advantage is reusability. Recent advances in software make such reverse engineering/re-engineering of this code into object oriented form possible. The purpose of this paper is to show how existing finite element code can be reverse/re-engineered to improve it. Taking sections of working finite element code, especially matrix computation for equation solution as examples, we put it through reverse engineering to arrive at the effective UML design by which development was done and then translate it to Java. This then is the starting point for analyzing the design and improving it without having to throw away any of the old code. Using auto-translators and then visually rewriting parts by the design so revealed, has no match in terms of speed and efficiency of re-engineering legacy code.
Protein Surface Functional Imaging
Authors: Cristea Paul Dan , Arsene Octavian , Tuduce Rodica , Nicolau Dan
Published: June 2012

The paper presents an image-oriented functional description of protein surfaces in terms of amphiphilicity (hydrophobicity / hydrophilicity) distribution. The actual discrete surface atom amphiphilicity distribution is replaced by an approximately equivalent amphiphilicity density distribution, computed in a standardized octagonal pattern around each atom. This representation is used to compute the resemblance of the neighborhoods of a pair of surface atoms – defined as the sum of the products of amphiphilicity densities of the corresponding patches (the pattern's central circles and the angular sectors in the same positions) in the two neighborhoods. The similitude and the interaction of a pair of atom neighborhoods are defined as their resemblance for parallel, respectively, anti-parallel orientations of the unit vectors perpendicular on the molecular surfaces in the points where the central atoms are located. These parameters, as well as the vector description of the neighborhoods, are used for the functional classification of surface atoms and for the study of protein interactions.
Simulation of Segmented Double-Gate MOSFETs
Authors: Reichardt Andras , Varga Gábor
Published: June 2012

Nowdays semiconductor manufacturing technology approaches its limit of miniaturization. There is a need for devices with low impact of miniaturization on its functionality. We present here simulation results of double-gate MOSFET devices with variable silicon channel width. Effects of segmentation is shown in characteristics of devices.
Numerical Simulation of MgB2 Superconducting Magnetic Energy Storage Coil
Authors: Mamalis Athanasios G. , Kladas Antonios , Theodorakopoulos Ioannis D.
Published: June 2012

A coupled thermal electromagnetic finite element analysis has been used to numerically simulate the electromagnetic characteristics of an MgB2 SMES coil. Magnetic field distribution data and current density predictions of the numerical model were compared with the literature and with the superconducting properties of explosively consolidated MgB2 samples measured experimentally. The material Jc characteristics were determined by applying Bean’s critical state model on the material magnetisation measurements conducted on a superconducting quantum interference device (SQUID).
Aircraft Mounted Neural Network Electrostatic Discharge (ESD) Location
Authors: Hoole Paul Ratnamahilan Polycarp , Aziz Nur Farah , Ganapathy Velappa , Jeevan Kanesan , Harikrishnan Ramiah , Hoole Samuel Ratnajeevan Herbert
Published: June 2012

Abstract. Cloud to ground and cloud to cloud lightning flashes pose a threat to the aircraft body and the electronic systems inside the aircraft. In this paper we present a single unit, as opposed to a three unit, lightning locator mounted on the aircraft that uses the wave-shapes of electromagnetic fields radiated by lightning and electrical activity ahead of the aircraft to locate the distance range of lightning activity. A three element array antenna scans the area ahead of the aircraft to narrow down the area ahead where the lightning or threatening electrical activity is. Moreover, the unique shape of the electric fields depending on the distance from the lightning activity is used by a neural network to train and recognize the distance range of the lightning activity from the aircraft on which the lightning detector is mounted. The combined use of the three element array antenna and the neural network provides the required knowledge of lightning activity for the pilot to take evasive action.
Fe-Mn-Si/6.5wt%Si-Fe Bilayer Ribbons produced by Using Melt Spinning Technique
Authors: Imamuara Daisuke , Todaka Takashi , Enokizono Masato
Published: June 2012

Recently, progress of the intelligent materials plays a big role in development of science and technology. We have ever tried to develop ferromagnetic shape memory alloys to expand application range of the common non-magnetic shape memory alloys, which are typical intelligent material. However the saturation magnetization and the shape memory effect were in a relation of trade-off, so we couldn’t get a good result. In this research, we tried to develop ferromagnetic shape-memory alloys as a composite material by using the single-roll melt spinning technique. They are bilayer ribbons, which have both shape memory layer and magnetic layer.
Magnetic Measurement and Model Based Characterisation of Phase Transformation in Lean Duplex Stainless Steel
Authors: Mészáros István
Published: June 2012

In the present work the microstructure and the strain induced phase transformation of a Lean Duplex Stainless Steel (LDSS) were studied. Sheet samples were cold rolled, the number of samples was nine; the applied deformation was up to 80%. The magnetization curves were measured by a single sheet tester-type magnetic property analyzer. The series of symmetrical minor hysteresis loops and the saturation loop were measured. Our novel data evaluation technique was applied for data evaluation of the magnetic measurements. This method is based on the multiphase-hyperbolic model of magnetization and it is called model based data evaluation (MBDE) technique. This method allowed us to separate the magnetic contribution of ferrite and martensite phases in the tested LDSS. Several new details of the kinetics of austenite→martensite strain induced phase transformation were clarified.
Differing Requirements for CCR4, E-Selectin, and α4β1 for the Migration of Memory CD4 and Activated T Cells to Dermal Inflammation
Authors: Gehad Ahmed , Al-Banna Nadia A. , Vaci Maria , Issekutz Andrew C. , Mohan Karkada , Latta Markus , Issekutz Thomas B.
Published: June 2012

CCR4 on T cells is suggested to mediate skin homing in mice. Our objective was to determine the interaction of CCR4, E-selectin ligand (ESL), and α4β1 on memory and activated T cells in recruitment to dermal inflammation. mAbs to rat CCR4 were developed. CCR4 was on 5–21% of memory CD4 cells, and 20% were also ESL+. Anti–TCR-activated CD4 and CD8 cells were 40–55% CCR4+, and ∼75% of both CCR4+ and CCR4− cells were ESL+. CCR4+ memory CD4 cells migrated 4- to 7-fold more to dermal inflammation induced by IFN-γ, TNF, TLR agonists, and delayed-type hypersensitivity than CCR4− cells. CCR4+ activated CD4 cells migrated only 5–50% more than CCR4− cells to these sites. E-selectin blockade inhibited ∼60% of CCR4+ activated CD4 cell migration but was less effective on memory cells where α4β1 was more important. Anti-α4β1 also inhibited CCR4− activated CD4 cells more than CCR4+ cells. Anti–E-selectin reduced activated CD8 more than CD4 cell migration. These findings modify our understanding of CCR4, ESL, α4β1, and dermal tropism. There is no strict relationship between CCR4 and ESL for skin homing of CD4 cells, because the activation state and inflammatory stimulus are critical determinants. Dermal homing memory CD4 cells express CCR4 and depend more on α4β1 than ESL. Activated CD4 cells do not require CCR4, but CCR4+ cells are more dependent on ESL than on α4β1, and CCR4− cells preferentially use α4β1. The differentiation from activated to memory CD4 cells increases the dependence on CCR4 for skin homing and decreases the requirement for ESL.
Role of M2b Macrophages in the Acceleration of Bacterial Translocation and Subsequent Sepsis in Mice Exposed to Whole Body [137Cs] Gamma-Irradiation
Authors: Kobayashi Makiko , Nakamura Kiwamu , Cornforth Michael , Suzuki Fujio
Published: June 2012

The influence of whole-body gamma-irradiation on the antibacterial host defense against Enterococcus faecalis translocation was investigated. Mice irradiated with or without 5 Gy [137Cs] gamma-rays were orally infected with 106 CFU/mouse E. faecalis. The pathogen was detected in the mesenteric lymph nodes (MLNs) of irradiated mice 1–4 d postinfection, whereas E. faecalis was not isolated from MLNs of normal mice. All irradiated mice died within 5 d of infection, whereas no mortality was shown in normal mice infected with the pathogen. Irradiated mice inoculated with normal mouse MLN macrophages (Mϕ) were shown to be resistant against the infection, although the same mice inoculated with irradiated mouse MLNMϕ (I-MLNMϕ) died postinfection. I-MLNMϕ were identified as IL-10+IL-12−CCL1+LIGHT+ Mϕ (M2bMϕ) and were shown to be inhibitory on Mϕ conversion from resident Mϕ to IL-10−IL-12+Mϕ (M1Mϕ). M2bMϕ were demonstrated in MLNs of mice 10–35 d after gamma-irradiation. M1Mϕ were not induced by E. faecalis Ag in cultures of I-MLNMϕ, whereas normal mouse MLNMϕ were converted to M1Mϕ in response to the Ag stimulation. After treatment with CCL1 antisense oligodeoxynucleotides, M2bMϕ disappeared in MLNs of irradiated mice, and M1Mϕ were generated in MLNs of these mice following E. faecalis stimulation. These results indicate that M2bMϕ presented in the I-MLNMϕ populations were responsible for the impaired resistance of mice irradiated with gamma-rays to bacterial translocation and subsequent sepsis. E. faecalis translocation and subsequent sepsis may be controlled immunologically by the intervention of M2bMϕ present in MLNs.
Prevention of mother to child transmission lay counsellors: Are they adequately trained?
Authors: Thurling Catherine H. , Harris Candice
Published: June 2012

South Africa’s high prevalence of human immunodeficiency virus (HIV) infected women requires a comprehensive health care approach to pregnancy because of the added risk of their HIV status. As a result of the shortage of health care workers in South Africa, lay counsellors play important roles in the prevention of mother to child transmission of HIV (PMTCT).There is no standardization of training of lay counsellors in South Africa, and training varies in length depending on the training organisation.The study aimed to investigate the training of lay counsellors by analysing their training curricula and interviewing lay counsellors about their perceptions of their training.A two phase research method was applied. Phase one documented an analysis of the training curricula. Phase two was semi-structured interviews with the participants. Purposive sampling was undertaken for this study. The total sample size was 13 people, with a final sample of 9 participants, determined at the point of data saturation.The research was qualitative, descriptive and contextual in design. The curricula analysed had different styles of delivery, and the approaches to learning and courses varied, resulting in inconsistent training outcomes. A need for supervision and mentorship in the working environment was also noted.The training of lay counsellors needs to be adapted to meet the extended roles that they are playing in PMTCT. The standardization of training programmes, and the incorporation of a system of mentorship in the work environment, would ensure that the lay counsellors are adequately prepared for their role in PMTCT.
Mag deur taal in 1 Johannes
Authors: Van der Watt Jan G.
Published: June 2012

Power through language in 1 John. Power is often exercised through language. Here it is argued that the author of John utilises different language strategies in order to exert power over and to influence his intended readers. His authority lies in his association with the ethos of the group which he feels he represents. From this position he makes his assumptions and builds his arguments. He also makes use of stereotypes to strengthen the identity of his group and to vilify the opponents who are no longer part of the group. His use of terms like koinōnia [fellowship] or filial language is also a powerful way to build the identity and social reality of his group.
Localized Corrosion of Stainless Steel in a Nuclear Waste Cooling Water System—Part 3: Development of a Large Artificial Pit
Authors: Whillock G.O.H. , Binks T.J. , Donohoe C.J.
Published: June 2012

To enable testing of candidate inhibitors for chloride-induced pitting of austenitic stainless steel in a radiation field, an artificial pit cell was required that was capable of sustaining corrosion at rates in the range revealed by plant inspections. Two designs of artificial pit cells are described. These allowed measurement of the internal and external cathodic contributions to the corrosion rate and changes in the composition of the artificial pit solution as time progressed. The number of electrolytic holes and the type and quantity of ferruginous sludge used were found to exert significant effects. The final design adopted on the basis of empirical testing demonstrated stable corrosion at a high rate (5 mm/y to 6 mm/y) in nominally 15 mg/L Cl− bulk solution containing 5 mg/L hydrogen peroxide (H2O2) at 60°C and stable pit solution composition for 20 days to 25 days at least. The initial strength of pit solution used was found to be unimportant, since the composition quickly gravitated toward 10 g/L to 20 g/L Cl− with a pH in the range of 1.5 to 2. For this composition, the corrosion reaction was driven almost exclusively by the external cathode, the internal hydrogen evolution ceasing to make a significant contribution.
Computational Fluid Dynamics Study of Solids Deposition in Heavy Oil Transmission Pipeline
Authors: Landry X. , Runstedtler A. , Papavinasam S. , Place T.D.
Published: June 2012

Previous studies have shown that transmission-quality heavy crude oil carries water-wetted solid particles, that these particles can accumulate on the pipe floor and cause under-deposit corrosion, and that the incidence of accumulation is strongly correlated to locations downstream of over-bends. This paper describes a computational fluid dynamics (CFD) analysis of light and heavy oil flow in a representative segment of a real transmission pipeline in which corrosion has been observed. The purpose was to gain insight into the key processes affecting deposition in heavy oil that do not occur for light oil and to offer suggestions for mitigation. The analysis suggests that the key effect in determining whether particles become trapped is the near-wall velocity of the flow, which is found to be significantly lower for heavy oil compared to light oil, especially downstream of over-bends. This causes particles near the pipe floor to move slowly and makes them susceptible to becoming trapped. It is interesting that the key process affecting deposition is not the tendency of particles to fall to the pipe floor, which occurs more readily in light oil than heavy oil, but, rather, the ability of the flow to keep particles moving along the pipe floor.
Corrosion Behavior of As-Cast Pb-Mg-Al Alloys in 3.5% NaCl Solution
Authors: Duan Y.H. , Sun Y. , He J.H. , Guo Z.Z. , Fang D.S.
Published: June 2012

Four kinds of Pb-Mg-Al alloys with Al contents of 0, 5, 10, and 15% (mass fraction) were prepared by induction melting. The corrosion behaviors of these four alloys were investigated by electrochemical measurements and immersion tests. The results indicate that Mg, Mg17Al12, and Mg2Pb phases in Pb-Mg-Al alloys form a microgalvanic cell between Mg2Pb and Mg in corrosive solution. The corrosion of Pb-Mg-Al alloys begins from corrosion at α-Mg. The volume fraction and distribution of Mg17Al12 in alloys significantly affect their corrosion resistance. The increasing volume fraction and continuous distribution of Mg17Al12 with the increase of Al content led to a better corrosion resistance. The Pb-Mg-Al alloy with 10% Al shows the best corrosion resistance.
Role of the Machining Residual Stresses on the Sulfide Stress Cracking Resistance of Carbon Steel Evaluated According to NACE TM0177 Method A
Authors: Mendibide C. , Michaud H. , Pineau F. , Marchebois H.
Published: June 2012

The goal of the study was to evaluate the effect of the machining conditions on the sulfide stress cracking (SSC) resistance of carbon steel. The paper presents the results obtained on two different carbon steel grades machined in conditions generating different surface residual stresses and correlates the stress state with the SSC resistance determined according to NACE TM0177 method A.
Corrosion Behavior of Carbon Steel in Acidified, Thiosulfate-Containing Brines
Authors: Kappes M. , Frankel G.S. , Sridhar N. , Carranza R.M.
Published: June 2012

The corrosion rate of carbon steel in acidified, thiosulfate-containing brines increased with thiosulfate content. Thiosulfate also increased the rate of cathodic and anodic reactions, as measured in polarization curves obtained shortly after immersion of the electrode. Current from iron dissolution was balanced by hydrogen evolution and reduction of thiosulfate to produce hydrogen sulfide. Hydrogen sulfide production represented a large fraction of the open-circuit corrosion current. Carbon steel specimens exposed to thiosulfate-containing solutions developed a film on their surface, composed of iron sulfide and cementite. The film was a good conductor of electrons and non-passivating. The rate of cathodic reactions measured for the film-covered electrode was faster than in the absence of the film, suggesting it is a good catalyst for reduction reactions. The ability of acidified, thiosulfate-containing brines to simulate hydrogen sulfide solutions was critically analyzed.
Educating Muslim Women and the Izala Movement in Zaria City, Nigeria
Authors: Renne Elisha P.
Published: June 2012

Expanding Islamic education has been a primary objective of the reformist Islamic movement, Jamaʿatu Izalat al-Bidʿa wa Iqamat al-Sunna (the Society for the Removal of Innovation and the Reinstatement of Tradition),also known as Izala. In the early 1980s, Izala leaders established classes for married women focusing on primary Islamic texts, particularly the Qurʾan and hadith, which were taught in several quarters in Zaria City, in northern Nigeria. Although Izala teachers and students initially faced considerable resistance, many married women insisted on attending classes and eventually, these classes came to be widely accepted. By 2002, over twenty-six Islamiyya schools with classes for married women had opened in Zaria City, which reflects both the widespread approval of married women’s education and a broader acceptance of the Izala movement there. Women’s attendance at these classes not only contributed to the introduction of the Izala’s underlying concepts but it also relates to theoretical debates concerning women’s autonomy and authority within Islam. While some may question the extent to which these classes have increased Muslim women’s agency, married women attending Izala classes in Zaria City have their own views about the position of women in their community and have sought to address this situation on their own terms.
Measurement of overall uptake coefficients for HO2 radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang, China
Authors: Taketani F. , Kanaya Y. , Pochanart P. , Liu Y. , Li J. , Okuzawa K. , Kawamura K. , Wang Z. , Akimoto H.
Published: June 2012

Abstract. HO2 uptake coefficients for ambient aerosol particles, collected on quartz filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect the HOx concentrations and chemistry.
Evaluation of the absolute regional temperature potential
Authors: Shindell D. T.
Published: June 2012

Abstract. The Absolute Regional Temperature Potential (ARTP) is one of the few climate metrics that provides estimates of impacts at a sub-global scale. The ARTP gives the time-dependent temperature response in four latitude bands (90–28° S, 28° S–28° N, 28–60° N and 60–90° N) as a function of the regional forcing imposed in those bands. It is based on a large set of simulations performed with a single atmosphere-ocean climate model. Here I evaluate ARTP estimates of regional temperature responses due to historic aerosol forcing in three independent climate models and show that the ARTP metric provides results in good accord with the actual responses in those models. Nearly all ARTP estimates fall within ±20% of the actual responses, and in particular for the tropics and the Northern Hemisphere mid-latitudes this range appears to be roughly consistent with the 95% confidence interval. Land areas within these two bands respond 41 ± 6% and 19 ± 28% more than the latitude band as a whole. The ARTP, presented here in a slightly revised form, thus appears to provide a relatively robust estimate for the responses of large-scale latitude bands and land areas within those bands to inhomogeneous radiative forcing.
A Tropospheric Emission Spectrometer HDO/H2O retrieval simulator for climate models
Authors: Field R. D. , Risi C. , Schmidt G. A. , Worden J. , Voulgarakis A. , LeGrande A. N. , Sobel A. H. , Healy R. J.
Published: June 2012

Abstract. Retrievals of the isotopic composition of water vapor from the Aura Tropospheric Emission Spectrometer (TES) have unique value in constraining moist processes in climate models. Accurate comparison between simulated and retrieved values requires that model profiles that would be poorly retrieved are excluded, and that an instrument operator be applied to the remaining profiles. Typically, this is done by sampling model output at satellite measurement points and using the quality flags and averaging kernels from individual retrievals at specific places and times. This approach is not reliable when the modeled meteorological conditions influencing retrieval sensitivity are different from those observed by the instrument at short time scales, which will be the case for free-running climate simulations. In this study, we describe an alternative, "categorical" approach to applying the instrument operator, implemented within the NASA GISS ModelE general circulation model. Retrieval quality and averaging kernel structure are predicted empirically from model conditions, rather than obtained from collocated satellite observations. This approach can be used for arbitrary model configurations, and requires no agreement between satellite-retrieved and modeled meteorology at short time scales. To test this approach, nudged simulations were conducted using both the retrieval-based and categorical operators. Cloud cover, surface temperature and free-tropospheric moisture content were the most important predictors of retrieval quality and averaging kernel structure. There was good agreement between the δD fields after applying the retrieval-based and more detailed categorical operators, with increases of up to 30‰ over the ocean and decreases of up to 40‰ over land relative to the raw model fields. The categorical operator performed better over the ocean than over land, and requires further refinement for use outside of the tropics. After applying the TES operator, ModelE had δD biases of −8‰ over ocean and −34‰ over land compared to TES δD, which were less than the biases using raw modeled δD fields.
Long-term changes in lower tropospheric baseline ozone concentrations at northern mid-latitudes
Authors: Parrish D. D. , Law K. S. , Staehelin J. , Derwent R. , Cooper O. R. , Tanimoto H. , Volz-Thomas A. , Gilge S. , Scheel H.-E. , Steinbacher M. , Chan E.
Published: June 2012

Abstract. Changes in baseline (here understood as representative of continental to hemispheric scales) tropospheric O3 concentrations that have occurred at northern mid-latitudes over the past six decades are quantified from available measurement records with the goal of providing benchmarks to which retrospective model calculations of the global O3 distribution can be compared. Eleven data sets (ten ground-based and one airborne) including six European, (beginning in the 1950's and before) three North American (beginning in 1984) and two Asian (beginning in 1991) are analyzed. When the full time periods of the data records are considered a consistent picture emerges; O3 has increased at all sites in all seasons. At European and North American sites the average linear increase of O3 before 2000 was approximately 1% yr−1 relative to the site's 2000 yr mixing ratio in each season. For perspective, this rate of increase sustained from 1950 to 2000 corresponds to an approximate doubling. At most European sites and some North American sites the rate of increase has slowed over the last decade (possibly longer) of the records. The average linear rate of increase before 2000 shows significant seasonal differences (1.08 ± 0.09, 0.89 ± 0.08, 0.79 ± 0.12 and 1.22 ± 0.12% yr−1 in spring, summer, autumn and winter, respectively, over North America and Europe).
Water isotope variations in the global ocean model MPI-OM
Authors: Xu X. , Werner M. , Butzin M. , Lohmann G.
Published: June 2012

Abstract. The stable water isotopes H218O and HDO are incorporated as passive tracers into the oceanic general circulation model MPI-OM, and a control simulation under present-day climate conditions is analyzed in detail. Both δ18O and δD distributions at the ocean surface and deep ocean are generally consistent with available observations on the large scale. The modelled δD-δ 18O relations in surface waters slightly deviates from the slope of the global meteoric water line in most basins, and a much steeper slope is detected in Arctic Oceans. The simulated deuterium excess of ocean surface waters shows small variations between 80° S and 55° N, and a strong decrease north of 55° N. The model is also able to capture the quasi-linear relationship between δ18O and salinity S, as well as δD and S, as seen in observational data. Both in the model results and observations, the surface δ−S relations show a steeper slope in extra-tropical regions than in tropical regions, which indicates relatively more addition of isotopically depleted water at high latitudes.
Intravitreal pegaptanib combined with diode laser therapy for stage 3+ retinopathy of prematurity in zone I and posterior zone II
Authors: Autrata Rudolf , Krejčířová Inka , Šenková Kateřina , Holoušová Marie , Doležel Zdeněk , Borek Ivo
Published: June 2012

Purpose

To investigate efficacy of intravitreal injection of pegaptanib and laser photocoagulation for treatment of stage 3+ retinopathy of prematurity (ROP) affecting zone I and posterior zone II, and to compare the results in terms of regression, development of peripheral retinal vessels, and final structural outcome with conventional laser photocoagulation or combined with cryotherapy.

Methods

In a prospective comparative study, 152 eyes with zone I, II posterior ROP 3+ (76 premature rabies), from 2009 to 2011, were included. Patients were randomly assigned to receive intravitreal pegaptanib (Macugen® 0.3 mg = 0.02 mL, Pfizer) with conventional diode laser photocoagulation in group 1 (68 eyes of 34 infants) or only laser therapy combined with cryotherapy in group 2 (84 eyes of 42 infants), bilaterally. The primary outcome of treatment success was defined as absence of recurrence of stage 3+ ROP. The mean follow-up after treatment was 19.3 months in group 1 and 21.5 months in group 2.

Results

Final favorable anatomic outcome and stable regression of ROP at last control examination was noted in 89.7% of eyes in group 1 and 60.8 % of eyes in group 2. Regression of plus disease and peripheral retinal vessels development appeared significantly more rapidly in group 1. No recurrence of neovascularization (stage 3+ ROP) was identified in 85.4% of patients in group 1 and 50% of patients in group 2.

Conclusions

Results of this study support the administration of intravitreal pegaptanib as useful therapy in the management of stage 3+ ROP.
Intravitreal pegaptanib as adjunctive treatment for stage 3+ ROP shown to be effective in a prospective, randomized, controlled multicenter clinical trial
Authors: Mintz-Hittner Helen A.
Published: June 2012

Purpose

Both intravitreal pegaptanib with laser therapy and intravitreal bevacizumab monotherapy have been found to be more efficacious than laser therapy alone in prospective, randomized, controlled clinical trials.

Results

The use of pegaptanib with laser therapy was efficacious in 91.2% compared with 69.0% in controls. The use of bevacizumab monotherapy was efficacious in 95.7% compared with 78.1% in controls.

Conclusions

The use of anti–vascular endothelial growth factor therapy for retinopathy of prematurity has been shown to be efficacious, without toxicity reported to date; however, the best drug and dose which allows greatest efficacy with fewest recurrences and without toxicity must be determined.
Acetylcholine Induces Human Detrusor Muscle Cell Proliferation: Molecular and Pharmacological Characterization
Authors: Arrighi Nicola , Bodei Serena , Zani Danilo , Simeone Claudio , Cunico Sergio Cosciani , Spano Pier Franco , Sigala Sandra
Published: June 2012

Introduction

The purpose of the study is to understand whether the cholinergic stimulation is important, not only in inducing contraction of the detrusor muscle, but also in modulating the proliferation of smooth muscle cells. These results could help to better understand the role of antimuscarinic drugs, which are currently used for the treatment of many urological diseases.

Patients and Methods

Primary cultures were prepared from biopsies of human detrusor muscle of subjects >65 years. From the cell culture set-up for each patient, mRNA was extracted and both the gene expression and the influence of increasing passages on the expression of muscarinic receptor subtypes were evaluated by semi-quantitative and quantitative PCR (RT-PCR and Q-RT-PCR). The rate of cell proliferation induced by cholinergic drugs was assessed by the evaluation of the [3H]-thymidine incorporation.

Results

The gene expression analysis demonstrated that the range of expression of muscarinic subtypes in human detrusor smooth muscle cells (HDSMCs) is M2 > M3 > M1 > M4 >> M5. The exposure to the cholinergic agonist carbachol induced a concentration-dependent increase in cell proliferation rate. The pharmacological characterization indicated that this effect was mainly mediated by the receptor subtypes M3 and M2.

Discussion

The cholinergic stimulation led to an increase in HDSMC proliferation, suggesting that this phenomenon might be involved in the pathogenic mechanism through which the cervico-urethral obstruction causes a detrusor hypertrophy, followed by a loss of function. These results could then provide an indication of the use of antimuscarinic drugs in the treatment of lower urinary tract disorders.
Hydration Water Freezing in Single Supported Lipid Bilayers
Authors: Toppozini Laura , Armstrong Clare L. , Kaye Martin D. , Tyagi Madhusudan , Jenkins Timothy , Rheinstädter Maikel C.
Published: June 2012

We present a high-temperature and high-energy resolution neutron scattering investigation of hydration water freezing in single supported lipid bilayers. Single supported lipid bilayers provide a well-defined biological interface to study hydration water dynamics and coupling to membrane degrees of freedom. Nanosecond molecular motions of membrane and hydration water were studied in the temperature range 240 K < T < 290 K in slow heating and cooling cycles using coherent and incoherent elastic neutron scattering on a backscattering spectrometer. Several freezing and melting transitions were observed. From the length scale dependence of the elastic scattering, these transitions could be assigned to freezing and melting of hydration water dynamics, diffusive lipid, and lipid acyl-tail dynamics. Coupling was investigated by comparing the different freezing and melting temperatures. While it is often speculated that membrane and hydration water dynamics are strongly coupled, we find that membrane and hydration water dynamics are at least partially decoupled in single bilayers.
FDTD Modeling of a Cloak with a Nondiagonal Permittivity Tensor
Authors: Okada Naoki , Cole James B.
Published: June 2012

We demonstrate a finite-difference time-domain (FDTD) modeling of a cloak with a nondiagonal permittivity tensor. Numerical instability due to material anisotropies is avoided by mapping the eigenvalues of the material parameters to a dispersion model. Our approach is implemented for an
elliptic-cylindrical cloak in two dimensions. Numerical simulations demonstrated the stable calculation and cloaking performance of the elliptic-cylindrical cloak.