bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesomorphic Properties of Three-Benzene-Ring Containing Bent-Core Liquid Crystals 1,3-Phenylene-bis[4-(alkylcarboyloxyl)benzylideneamine]
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai
Published: January 2010

A homologous series of three-benzene-ring containing bent-cores compounds 1,3-phenylene-bis[4-(alkylcarboyloxyl)benzylideneamine] were synthesized. In these molecules the terminal ester chains CH3(CH2)n-2COO-, where n was the number of carbon atoms in the terminal chains, were linked to the central three-benzene-ring containing bent-core. As n changed from 1-12, the melting temperatures and clearing points were in the high temperature ranges of 136-206oC. As n changed in the range of 14-19, the melting temperatures and clearing points were dramatically dropped in a low temperature ranges 60-82oC.
Photonic Crystal Fabry-Perot Self-Collimation Interferometer by Liquid Crystal Infiltration
Authors: Lai Guo Zhong , Chen Xi Yao , Wang Yu Fei , Lin Hong
Published: January 2010

A Fabry-Perot self-collimation interferometer (FPSI) constructed in a two-dimensional photonic crystal (2D PhC) by liquid crystal infiltration has been proposed and demonstrated theoretically. The resonant cavity of FPSI is infiltrated with a nematic liquid crystal (LC) 5CB with ordinary and extraordinary refractive indices 1.522 and 1.706, respectively. The transmission spectrum of the FPSI has been investigated with the 2D finite-difference time-domain method. Calculation results show that resonant transmission peaks have nearly equal frequency spacing 0.0090c/a. When the effective refractive index neff of the liquid crystal is increased from 1.522 to 1.706, the peaks shift to the lower frequencies over 0.0071c/a while the peak spacing is almost kept unchanged. Thus this FPSI by LC infiltration can work as a tunable attenuator or an optical switch. For the central operating wavelength around 1.55m, its dimensions are only about tens of microns. Thus this device may be applied to photonic integrated circuits.
Field Emission Behavior of the Transferred Substrate Aligned Array Carbon Nanotube Films
Authors: Zeng Xiao Shu , Yi Yi Wu , Du Zao Hong , Luo Chao
Published: January 2010

A novel technology is explored, using which an aligned array carbon nanotube film (aacf) can be perfectly peeled off from itself growing substrate as well as transferred onto an aluminum tape substrate, being assembled a composite film together with the Al tape. The electrical conductance and the field emission behaviors have been tested for the composite films. Experimental results show that the composite film has electrical resistance between 10 ohm and 1127 ohm, which depends on thickness and quality of the sticky glue layer between the carbon nanotub (cnt) film and the Al substrate. F-N curve proves the electronic emission of the composite film is field emission. I-V measurement curves demonstrate that the composite film with good electrical conductance has better field emission behavior and that the turn-on field and threshold field of sample 1 are 1.1 V/um and 1.8 V/um respectively. The technology datum show the composite film can meet the requirements of the emission cathode in flat panel displays.
Synthesis and Mesogenic Properties of a Novel Hyperbranched Triphenylene-Based Discotic Liquid Crystal
Authors: Zhang Chun Xiu , Pu Jia Ling , He Zhi Qun , Zhang Ming , Wu Hao , Li Ya Nan
Published: January 2010

A novel triphenylene-based hyper-branched macromolecule was synthesized from the functional compound-2, 6, 10-trihydroxy-3, 7, 11–tris (pentyloxy) triphenylene serving as core, using α,ω-dibromodecane as spacer and 1-bromopentane as terminal group for end capping by using a very simple synthesis method, one-pot reaction. The structure of the hyperbranched macromolecule was determined by FTIR and 1HNMR. The molecule weight and the molecular weight distribution were measured by GPC. Mesophase and their structural orders were determined using a polarized optical microscope and a differential scanning calorimeter.
Synthesis and Mesomorphic Properties of Three-Benzene-Ring Containing Bent-Core Liquid Crystal 1,3-Phenylene-bis[4-(nonylcarboyloxyl) benzylideneamine]
Authors: Huang Yuan Ming , Ma Qing Lan , Zhai Bao Gai
Published: January 2010

A bent-core compound with three benzene-ring cores 1,3-phenylene-bis [4-(nonylcarboyloxyl)benzyl ideneamine] was synthesized. Its mesomorphic properties were characterized with differential scanning calorimetry and polarized optical microscopy, respectively. This kind of bent-core compound exhibited mesophases in the temperature range of 155-185oC for the first cooling but cyclic heating and cooling could lower the phase transition temperatures for this bent-core liquid crystal. Our results demonstrated that bent-core molecules with three benzene-ring cores can also form mesophases as those five benzene-ring containing bent-core molecules do.
Synthesis and Characterization of Novel Triphenylene Derivatives Having Carboxylic Acid Groups at the Peripheral Chains
Authors: Li Zhong Xiao , Wei Wei , Fan Wu Kun , Pu Jia Ling
Published: January 2010

A new kind of triphenylene derivative sym-(OC3H6OCOC2H4COOH)6 with triphenylene at the core and carboxyl groups at the peripheral chains was synthesized and characterized by FT-IR and 1H-NMR. Thermal gravimetry analysis (TGA) and differential scanning calorimetry (DSC) showed that these compounds have a good thermal stability, which is dependent on the flexibility and interaction of the peripheral chains. Red shifts in electronic absorption spectra of the compounds were found in solution with increasing concentration.
Long-Term Efficiency of Two Organic Corrosion Inhibitors for Reinforced Concrete
Authors: Pereira E.V. , Figueira R.B. , Salta Manuela M. , Fonseca I.T.E.
Published: January 2010

In this paper the efficiency of two organic corrosion inhibitors, a migratory and an admixture inhibitor, was evaluated by electrochemical techniques in solutions simulating the interstitial electrolyte of concrete and on concrete slabs exposed to natural environmental conditions over a five-year period. From obtained results, the usefulness of the two products is discussed aiming its application in new structures to prevent chlorides induced corrosion and as a curative method for repairing reinforced concrete structures contaminated with chlorides and affected by reinforcement corrosion.
Characterisation of Ti/Al Multilayered Structures with Slow Positron Beams Applying a Simplified Positron Depth Distribution Model
Authors: Duarte Naia Marco , Gordo Paulo M. , Teodoro Orlando M.N.D. , de Lima Adriano P. , Moutinho Augusto M.C.
Published: January 2010

In this work the depth of interfaces in multilayered structures was estimated. The fractions of positron annihilation as function of the implantation energy were estimated from an S-W plot and then converted into a function of the sample depth through the positron implantation profile in the multilayer system computed from a reduced positron profile. The results of this method in Ti/Al samples are comparable to those using the common analysis based on positron diffusion equations. The positron analyses results were compared with SIMS profiles for the same samples.
Obtaining an Optimum Weight for a Composite Pressure Vessel
Authors: Moharrerzadeh S. , Atai A.
Published: January 2010

Weight of a composite cylindrical pressure vessel is an important issue investigated here. Design variables include number of layers and thickness, ply angle, volume fraction, and material properties in each layer. The constraint is based on Hoffman criterion and the optimization technique is a messy genetic algorithm (mGA). It is shown that with multilayered structure, we can have a vessel with a weight less than half of that for a single layered composite vessel under a given internal pressure.
Strength Prediction and Experimental Validation of Adhesive Joints Including Polyethylene, Carbon-Epoxy and Aluminium Adherends
Authors: Pinto A.M.G. , Magalhães A.G. , Campilho Raul D.S.G. , de Moura Marcelo F.S.F. , Baptista A.P.M.
Published: January 2010

Polyolefins are especially difficult to bond due to their non-polar, non-porous and chemically inert surfaces. Acrylic adhesives used in industry are particularly suited to bond these materials, including many grades of polypropylene (PP) and polyethylene (PE), without special surface preparation. In this work, the tensile strength of single-lap PE and mixed joints bonded with an acrylic adhesive was investigated. The mixed joints included PE with aluminium (AL) or carbon fibre reinforced plastic (CFRP) substrates. The PE substrates were only cleaned with isopropanol, which assured cohesive failures. For the PE CFRP joints, three different surfaces preparations were employed for the CFRP substrates: cleaning with acetone, abrasion with 100 grit sand paper and peel-ply finishing. In the PE AL joints, the AL bonding surfaces were prepared by the following methods: cleaning with acetone, abrasion with 180 and 320 grit sand papers, grit blasting and chemical etching with chromic acid. After abrasion of the CFRP and AL substrates, the surfaces were always cleaned with acetone. The tensile strengths were compared with numerical results from ABAQUS® and a mixed mode (I+II) cohesive damage model. A good agreement was found between the experimental and numerical results, except for the PE AL joints, since the AL surface treatments were not found to be effective.
Behaviour of Cement and Polymer Mortar Materials to Rapid Freeze-Thaw Cycling
Authors: Ribeiro M.C.S. , Juvandes L.F.P. , Rodrigues J.D. , Ferreira Antonio , Marques António Torres
Published: January 2010

The aim of this investigation work is threefold: 1) To analyse and quantify freeze-thaw resistance of glass fibre reinforced epoxy polymer mortars, comparatively to both normal cement mortars and plain epoxy polymer mortars; 2) To determine glass fibre reinforcement effect on freeze-thaw behaviour; and 3) To evaluate the reliability of ASTM C666M-03 test methodology for the assessment of freeze-thaw resistance of polymer concrete materials. For this purpose several test specimens, normal cement mortars, plain and glass-fibre reinforced epoxy polymer mortars were submitted to freeze-thaw cycling between 36 up to 300 cycles, according to the above norm. Dynamic elasticity modulus, with basis on fundamental resonance frequency measurements, was calculated every 36 cycles, and the correspondent relative dynamic elasticity modulus was determined for each cycling period. In order to assess the reliability of this non-destructive test methodology, three specimens of each formulation were withdrawn at regular periods and tested in bending and compression. Relative mechanical strengths, as function of conditioning period, were compared with corresponding relative dynamic modulus of elasticity.
Printed Circuit Boards Recycling: Characterization of Granulometric Fractions from Shredding Process
Authors: Oliveira Paula C. , Cabral Marta , Nogueira Carlos A. , Margarido Fernanda
Published: January 2010

In electronic appliances, printed circuit boards (PCB) represent an important component, containing high grade of valuable metals, besides organic resins and some ceramic materials. Copper is the major metal in PBC’s composition (normally higher than 20% w/w) but many other secondary and minor metal elements, including precious metals, are found in PCB’s. Recycling of PCB´s involves firstly the shredding operation, which is crucial in order to liberate particles from different materials, allowing its further processing by other mechanical, physical and chemical technologies. An efficient shredding operation is difficult to achieve due to the high heterogeneity of these wastes involving materials with different mechanical properties and complex assemblies. This paper presents results from laboratorial studies of shredding of PCB’s and the evaluation of size reduction efficiency as well as the chemical characterization of the obtained shredded fractions. Results showed that an efficient size reduction (characteristic average diameter d50=1.0mm) is obtained using two shredding stages of PCB’s, the first one with a grab shredder and the second one with a cutting mill. Chemical analysis of shredded PCB’s indicated that copper is the principal metal present (28%) followed by Sn, Zn, Pb and Al (3-5%) and many other minor elements. The fine fractions were rich in plastic materials while the metals were essentially present in the intermediate fractions (0.3-1.5 mm). These results can lead to guidelines regarding further design of the physical separation steps in the recycling processes.
Evaluation of the Relationship between Diamond Tool Wear Performance and the Mechanical Properties of the Individual Metallic Binders
Authors: Amaral Pedro M. , Coelho Adriano , Anjinho Carlos A. , Fernandes Jorge Cruz , Rosa Luis Guerra
Published: January 2010

A test methodology is employed to investigate the cutting behaviour of five different diamond impregnated tools for cutting hard materials, such as rocks. A set of parameters, which characterise the tool wear (specific wear loss in the tool), and its relationship with the cutting force of the examined tools, are established to evaluate the tool wear performance. The procedure established in this work describes the specifications of the equipment used to carry out the tests, the different cutting conditions, the format of the output parameters and the characterisation of the different materials used (binders and rocks), hence allowing to discuss the overall cutting wear behaviour of the tools. The methodology presented indicates a universally applicable procedure for measuring the wear performance of the diamond tools as, at the same time, it establishes a relationship between wear and the mechanical parameters of the different metallic binder materials used to manufacture the correspondent tools. The procedure is proven to be an indispensable instrument for correctly carrying out wear performance tests and for reliably interpreting the wear mechanisms of the tool.
Viscoelastic Properties Assessment of Syntactic Foams by Dynamic Mechanical Analysis
Authors: Capela Carlos , Ferreira José A. Martins , Costa José Domingos M.
Published: January 2010

Low-density sheet moulding compounds incorporating hollow glass micro-spheres are being increasing used namely in automotive industry, boats and deep-water submarines and core materials. This paper presents the results obtained in a current study of the viscous properties on hybrid short fibre/hollow glass microspheres composites fabricated with epoxy binder. Dynamic mechanical analysis (DMA) was used to study the effect of the filler volume fraction and of the addition of glass fibre reinforcement on the dynamic stiffness modulus, damping coefficient and glass transition temperature in tensile mode. The specimens were cut from plates produced by resin transfer moulding in vacuum with microspheres weight contents up to 13%. Elastic modulus decreases significantly with the increasing of filler volume fraction. In contrary, it increases significantly with the glass fibre reinforcement content. Glass transition temperature apparently tends to decrease with microspheres and of glass fibre reinforcement’s content. Tmax temperatures tend to increase slightly with the addition of fibre reinforcements and the microsphere filler. Maximum damping coefficient is much lower for the foams when compared with net resin.
The Backing Bar Role in Heat Transfer on Aluminium Alloys Friction Stir Welding
Authors: Rosales M.J.C. , Alcantara N.G. , Santos Jorge , Zettler R.
Published: January 2010

Although new structural and advanced materials have been used in the automotive and aircraft industries, especially lightweight alloys and advanced high strength steels, the successful introduction of such materials depends on the availability of proven joining technologies that can provide high quality and performance joints. Solid-state joining techniques such as Friction Stir Welding (FSW) are a natural choice since their welds are produced at low temperatures, so the low heat input provides limited, slight distortion, microstructural and mechanical degradation. Great effort has currently been devoted to the joining of Al-Cu-Mg and the Al-Mg-Si alloys because of their high strength, improved formability, and application in airframe structures. FSW is a continuous, hot shear, autogenous process involving a non-consumable and rotating tool plunged between two abutting workpieces. The backing bar plays an important role in heat transfer from stir zone (SZ), which can influence the weld microstructure as well as the consolidation of material in the root of the join. This study aims at investigating issues concerning heat generation, within the SZ of friction stir welded aircraft aluminium alloys.
Composition and Microstructures of Imperial Brass Chinese Coins
Authors: Furtado M.J. , Silva Rui Jorge C. , Araújo M.F. , Braz Fernandes Francisco Manuel
Published: January 2010

Twenty brass Chinese cash coins with complex compositions were studied for a better understanding of the metallurgical cash production in China, during the 17th, 18th and 19th centuries. Elemental composition was obtained through energy-dispersive micro X-ray fluorescence spectrometry of small cleaned areas on the coins rims. Results showed that these brass alloys (Cu-Zn) frequently contain up to 3% Sn, have highly variable Pb content (from n.d. up to 14%) and Fe, Sb, and As as minor elements. Microstructures were assessed by optical microscopy, scanning electron microscopy with energy dispersive spectroscopy, and preliminary micro X-ray diffraction analysis. All the coins present typical as-cast microstructures although very fine-grained, which are supported by binary (Cu-Zn) and ternary (Cu-Zn-Sn) equilibrium phase diagrams, that explain microstructural differences due to the presence of Sn in these brasses.
The Effect of Widmanstätten and Equiaxed Microstructures of Ti-6Al-4V on the Oxidation Rate and Creep Behavior
Authors: Sugahara Tarcila , Reis Danieli A.P. , de Moura Neto Carlos , Barboza M.J.R. , Perez E.A.C. , Neto Francisco Piorino , Hirschmann Ana Coh O.
Published: January 2010

Ti-6Al-4V is currently used in aeronautic and aerospace industry mainly for applications that require resistance at high temperature such as, blades for aircraft turbines and steam turbine blades. The titanium affinity by oxygen is one of main factors that limit the application of their alloys as structural materials at high temperatures. Notable advances have been observed in the development of titanium alloys with the objective of improving the creep properties. Increased oxygen levels are associated with increased microhardness and decreased ductility in titanium. In spite of this, Ti-6Al-4V containing an (+) structure continues to be the workhorse of the titanium industry due to their high specific strength, corrosion resistance, excellent high temperature properties and metallurgical stability. The objective of this work was to study the influence of equiaxed and Widmanstätten microstructures on oxidation rates and creep behavior of the Ti-6Al-4V alloy. The samples were exposed to different conditions of time and temperature to evaluate the oxidation rates. This influence on the oxidation rates was evaluated in terms of weight gain, -case depth and microhardness profile at 500 and 600 °C. Preliminary results indicated that the equiaxed microstructure with average grain size of 10 m exhibits faster oxygen diffusion. Short-term creep tests were performed under constant load in a stress range from 291 to 472 MPa at 500 °C and in a stress range from 97 to 291 MPa at 600 °C. The stress exponents obtained lie in the range from 4.0 to 11.3. The apparent activation energies for steady-state creep determined in the present work were estimated to be 316 and 415 kJ/mol at 291 MPa for the equiaxed and Widmanstätten microstructures, respectively. On the basis, the creep of Ti-6Al-4V is consistent with the lattice diffusion-controlled dislocation climb process in -Ti, for both microstructures. The creep rates of Widmanstätten microstructure were two orders of magnitude lower than of equiaxed microstructure in both temperatures. Apparently, the higher creep resistance with a Widmanstätten microstructure can be attributed to / interfaces acting as obstacles to dislocation motion and to the average grain size of 395 m, which reduces the grain boundary sliding, dislocations sources and the rate of oxygen diffusion along grain boundaries.
Tensile Ductility of Cast TiAl Alloys
Authors: Hu Da Wei , Wu Xin Hua
Published: January 2010

The microstructural characteristics and room temperature tensile ductility in some cast TiAl alloys were analyzed. It was found that grain refinement, either through Q&A treatment in boron-free alloys or through low dose of boron addition in beta solidifying alloys with lamellar microstructures, is not sufficient for good ductility. For cast alloys with convoluted microstructures and fine lamellar microstructures the orientation distribution of gamma grains/lamellar colonies plays an important role in controlling ductility. In those fine-grained alloys a highly random orientation distribution of gamma grains/lamellar colonies is essential to improvement in ductility.
Nanocrystalline LPSO Mg-Zn-Y-Al Alloys with High Mechanical Strength and Corrosion Resistance
Authors: Okouchi Hitoshi , Seki Yoshikazu , Sekigawa Takahiro , Hira Hirohito , Kawamura Yoshihito
Published: January 2010

Interests in magnesium alloys increase as eco-material for its lightweight, and many investigations have been carried out on the development of manufacturing processes and alloy development. In 2001, Mg97Zn1Y2 (at%) alloy with a tensile yield strength of 610 MPa and an elongation of more than 5 % has been developed by rapidly solidified powder metallurgy (RS P/M) processing. The developed alloy was characterized by a novel phase with long period stacking ordered (LPSO) structure. Recently, we have investigated new compositions for LPSO RS P/M Mg-Zn-Y-X alloys in order to improve the corrosion resistance of the RS P/M Mg97Zn1Y2 alloy with maintaining the superior mechanical properties. Consequently, we have developed a RS P/M Mg96.7Zn0.85Y2Al0.45 alloy with high strength and high corrosion resistance. The RS P/M Mg96.7Zn0.85Y2Al0.45 alloy contained the LPSO phase and exhibited a tensile strength of 525 MPa, an elongation of 9 % and a fatigue strength of 325 MPa, which were similar to those of the RS P/M Mg97Zn1Y2 alloy. However, the corrosion resistance of the RS P/M Mg96.7Zn0.85Y2Al0.45 alloy was 1.5 times that of the RS P/M Mg97Zn1Y2 alloy. The specific tensile yield strength, the specific fatigue strength and the corrosion resistance of the RS P/M Mg96.7Zn0.85Y2Al0.45 alloy were about 1.7 times, 1.8 times, and twice those of extra-super-duralumin (7075-T6 or 7075-T73), respectively.
Effect of PFZ and Grain Boundary Precipitate on Mechanical Properties and Fracture Morphologies in Al-Zn-Mg(Ag) Alloys
Authors: Ogura Tomo , Hirose Akio , Sato Tatsuo
Published: January 2010

The effect of PFZ and grain boundary precipitates formed in aging processes on the macroscopic mechanical properties in Al-Zn-Mg(-Ag) alloys were evaluated using TEM, SEM, tensile test and nanoindentation. Decreases in width of PFZ and smaller size of grain boundary precipitates aging at lower temperatures and/or the addition of Ag processes improved the tensile properties, and the presence of PFZ was found to be harmful to the fracture. Nanoindentation hardness results clarified that the hardness within PFZ is smaller than that in grain interiors, indicating that, in the alloy with large width of PFZ, preferential deformation occurs within PFZ in the initial stage of deformation, and this causes lower elongation regardless of the same level of proof stress and the same sizes of grain boundary precipitates. From the quantitative correlation between precipitate microstructures in the vicinity of grain boundaries, mechanical properties and fracture morphologies, the deformation process of the alloys is considered to divided by three types; i.e. in case of the alloys with the small width of PFZ and the small size of grain boundary precipitates, in case of the alloys with the large width of PFZ and the small size of grain boundary precipitates and in case of the alloys with the large width of PFZ and the large size of grain boundary precipitates.
Appearance of Non-Equilibrium α-Aluminum Grains in Hypereutectic Al-Si Alloy through Sono-Solidification
Authors: Tsunekawa Yoshiki , Taga Kanako , Fukui Yuta , Okumiya Masahiro
Published: January 2010

Ultrasonic vibration has been applied to various molten metal processes owing to the functions of (a) improvement in wettability, (b) liquid adhesion at a vibrating end surface and (c) sono-solidification such as grain refinement. The present study is focused on the sono-solidification with acoustic cavitaion in hypereutectic Al-18mass%Si alloy. There appears an equilibrium microstructure composed of primary silicon and coupled eutectic -Al/Si phases in Al-18mass%Si alloy, however, non-equilibrium -Al grains develop along with the equilibrium phases through the sono-solidification. During the sono-solidification of Al-18mass%Si alloy, non-equilibrium -Al grains are recognized in the molten metal close to the ultrasonic radiator just before reaching the eutectic temperature of 577 oC in addition to the refined primary silicon particles. The appearance of -Al grains is understood through acoustic cavitation: ultrasound in molten Al-Si alloys exhibits two outstanding behaviors of cavitation bubbling and acoustic streaming. Firstly the de-coupled eutectic reaction, which is recognized in the solidified eutectic Al-Si alloy with severe stirring, causes divorced -Al grains by the acoustic streaming with cavitation. Secondly it is expected that high pressure of over 1 GPa generated by the collapse of cavitaion babbles leads to not only an increase in the eutectic temperature, but also higher silicon content at the eutectic point in Al-Si alloy. Consequently, non-equilibrium -Al grains are nucleated at collapsed cavitaion bubble sites, and they are characterized by higher silicon content compared with that of primary -Al grains in hypoeutectic Al-7masst%Si alloy.
The Structure and its Dependence on the Magnetic Properties of Ni5CoXCu95-X Alloys Produced by Mechanical Alloying and Subsequent Annealing
Authors: López Marta , Gómez M. Elena , Reyes David , Ramam K. , Mangalaraja Ramalinga V. , Prieto Pedro , Jiménez José A.
Published: January 2010

Lower energy-ball milling was used to prepare magnetic granular Ni5CoXCu95-X alloys produced by mechanical alloying through a milling process and subsequent annealing process, have been investigated. The pure copper shows high electrical conductivity and malleability, however the Cu-Co system in the thermodynamic equilibrium is non-soluble below 500°C. Nevertheless, mechanical alloyed particles of Cu with 5-7%Co and 5%Ni can be subjected to annealing at 500°C or consolidation-sintering treatments to obtain composite materials thereby improving their mechanical and magnetic properties suitable for electronic devices. The ultrafine Co and (Co,Ni) particles reduced and dispersed in the copper powder matrix with milling times of 20 to 60 h and thus affected the magnetic properties of the as-milled Ni5CoXCu95-X powder obtained from this non-equilibrium phases synthesis. The magnetic properties of the supersaturated solid solutions are strongly dependent on the interactions among the magnetic particles and the nanometric size of these particles. The morphology, structure and size of as-milled and sintered powders were characterized by SEM, HRTEM and XRD techniques. The results show that the microstructure, hardness and magnetic properties of the granular Ni5CoXCu95-X alloy have strong dependence of milling time. The continuous decrement of Ms as a function of milling time is a consequence to the variation of phase in the composition with formation of CoNi particle and the partial change of fcc-Co to hcp-Co. Super-paramagnetic behavior is observed in both as-milled and annealed powders, with a maximum Hc of 250-260 Oe obtained for 7%Co after 60h of milling. The effect of Nickel on the Ni5CoXCu95-X can be explained as Ni content inhibit the two-solid (Cu-Co) phases segregation of the alloys when annealed at high temperature, leading to a grained structure with precipitated Co particles in homogeneous Cu-Ni strengthened solid solution matrix.
Malignancy risk in patients with giant cell arteritis: A population‐based cohort study
Authors: Kermani Tanaz A. , Schäfer Valentin S. , Crowson Cynthia S. , Hunder Gene G. , Gabriel Sherine E. , Ytterberg Steven R. , Matteson Eric L. , Warrington Kenneth J.
Published: January 2010

Objective

To determine the incidence of cancer in a population‐based cohort of patients with giant cell arteritis (GCA) compared with age‐ and sex‐matched referent subjects.

Methods

Using the resources of the Rochester Epidemiology Project, all incident cases of GCA diagnosed between January 1, 1950 and December 31, 2004 were identified. For each GCA patient, 2 subjects without GCA of the same sex and similar age and length of medical history were selected. Diagnosis of malignancy was made by histopathology. Patients were followed until death, last contact, or December 31, 2006.

Results

Our study included 204 GCA patients and 407 non‐GCA subjects. The GCA cohort had 163 (79%) women and 41 (21%) men, a mean ± SD age of 76.0 ± 8.2 years, and a median followup of 7.7 years. The non‐GCA cohort consisted of 325 (80%) women and 82 (20%) men, a mean ± SD age of 75.6 ± 8.4 years, and a median followup of 8.1 years. During followup, 46 GCA patients and 76 non‐GCA subjects developed cancer (hazard ratio [HR] 1.26, 95% confidence interval [95% CI] 0.87–1.83). Adjustment for smoking did not alter the results. The 1‐, 10‐, and 20‐year cumulative incidences of any malignancy were 5.9%, 33.6%, and 50.0% among GCA patients and 2.6%, 27.0%, and 47.0% among non‐GCA patients, respectively. There were no differences in hematologic or solid malignancies between both groups. Colon cancer appeared more commonly in the GCA group (P = 0.07). Mortality following cancer was similar in both cohorts (HR 0.80, 95% CI 0.52–1.24).

Conclusion

GCA patients are not at an increased risk of first cancer after diagnosis.
Health care utilization for musculoskeletal disorders
Authors: MacKay Crystal , Canizares Mayilee , Davis Aileen M. , Badley Elizabeth M.
Published: January 2010

Objective

To examine patterns of ambulatory care and hospital utilization for people with musculoskeletal disorders (MSDs), including arthritis and related conditions, bone and spinal conditions, trauma and related conditions, and unspecified MSDs.

Methods

Administrative data from the Ontario Health Insurance Plan database for ambulatory care physician visits, the National Ambulatory Care Reporting System database for day (outpatient) surgeries and emergency department visits, and the Discharge Abstract Database for hospital discharges were used to examine health care utilization for MSDs in fiscal year 2006–2007. Person visit rates (number of people with physician visits or hospital encounters per population) were calculated.

Results

Overall, 22.3% of Ontario's population (2.8 million persons) saw a physician for an MSD in ambulatory settings. Person visit rates were highest for arthritis and related conditions (107.7 per 1,000 population), followed by trauma and related conditions (89.6 per 1,000 population), unspecified MSDs (71.0 per 1,000 population), and bone and spinal conditions (62.4 per 1,000 population). The majority of visits were to primary care physicians, with 83.2% of those with visits for all MSDs seeing a primary care physician at least once. Overall, 33.0% of people with a physician visit for an MSD saw a specialist, with orthopedic surgeons being the most commonly consulted type of specialist. In hospital settings, person visit rates for MSDs were highest in the emergency department, followed by day surgeries and inpatient hospitalizations.

Conclusion

The findings of our study highlight the magnitude of health care utilization for MSDs and the central role of primary care physicians in the management of these conditions.
Clinical course and prognostic value of disease activity in the first two years in different subtypes of juvenile idiopathic arthritis
Authors: Albers H. M. , Brinkman D. M. C. , Kamphuis S. S. M. , van Suijlekom‐Smit L. W. A. , van Rossum M. A. J. , Hoppenreijs E. P. A. H. , Girschick H. J. , Wouters C. , Saurenmann R. K. , Houwing‐Duistermaat J. J. , Huizinga T. W. J. , Schilham M. W. , ten Cate R.
Published: January 2010

Objective

Juvenile idiopathic arthritis (JIA) is a heterogeneous disease involving chronic arthritis. The clinical course is characterized by a fluctuating pattern of active and inactive disease. We have described in detail the clinical course in different JIA subtypes during the first 2 years after diagnosis and studied its relationship to disease activity in the following years.

Methods

Detailed clinical data on different parameters describing the disease activity in sequential time periods covering the first 2 years after diagnosis were retrieved from the charts of 311 patients with JIA and compared between subtypes. In a cohort of 146 patients, the relation of these different clinical variables to the course of disease in the following 3 years was evaluated.

Results

The percentage of time with active disease in the first 2 years differed significantly between subtypes. In all subtypes, a broad spectrum of activity was observed. The time with active disease in the first 2 years was the most significant factor associated with the duration of active disease in the following years.

Conclusion

Different percentages of time with active disease have been observed between JIA subtypes in the first 2 years. The cumulative duration of activity varied widely within each subtype. Regarding the prognosis of the individual patient, the clinical course in the first 2 years appears to be predictive of the clinical course in the following years. Patients that have less time with active disease in the first 2 years are not likely to develop an unremitting clinical course later on.
Validity of self‐reported rheumatoid arthritis in a large cohort: Results from the Black Women's Health Study
Authors: Formica Margaret K. , McAlindon Timothy E. , Lash Timothy L. , Demissie Serkalem , Rosenberg Lynn
Published: January 2010

Objective

To evaluate the positive predictive value (PPV) of 3 case definitions of rheumatoid arthritis (RA) based on self‐reported data on RA diagnosis and use of arthritis medications, and to determine whether a validated screening survey would increase the PPVs in the 3 groups.

Methods

Medical records and physician checklists were reviewed for confirmation of an RA diagnosis among a sample of Black Women's Health Study participants who reported incident RA and were categorized according to reported medications: disease‐modifying antirheumatic drugs (DMARDs) (n = 102), nonsteroidal antiinflammatory drugs (NSAIDs) (n = 100), and no arthritis medications (no meds) (n = 101). PPVs for confirmed RA were calculated for each of the medication groups, both overall and according to the results of the screening survey.

Results

The PPVs of confirmed RA were 76%, 61%, and 29% in the DMARDs, NSAIDs, and no meds groups, respectively. After exclusion of women who reported other rheumatic conditions or who reported taking only prednisone, the PPV increased in the DMARDs group to 88%, but little improvement was seen in the other groups. The PPVs increased somewhat according to results of the screening survey for the DMARDs group (92% for positive screen versus 85% for negative screen; P = 1.00), and increased substantially for the NSAIDs group (89% versus 38%, respectively; P = 0.03), but only 43% of participants completed the survey.

Conclusion

We found that self‐report of RA, along with self‐reported DMARDs, is a useful case definition for identifying confirmed RA. The validated screening survey could be useful for identifying cases of confirmed RA in some, but not all, medication groups.
Hindered diffusion of residue narrow cuts through polycarbonate membranes
Authors: Chen Zhentao , Xu Chunming , Gao Jinsen , Zhao Suoqi , Xu Zhiming
Published: January 2010

Hindered diffusion plays an important role in catalytic processing of residue and heavy oil because of large size molecules in these feedstocks. Vacuum residue of Athabasca oil sand bitumen was fractionated into 13 narrow fractions and an end‐cut by supercritical fluid extraction and fractionation (SFEF). Diffusion transport of five SFEF cuts through four polycarbonate membranes was investigated using a diaphragm cell at 308 K. The results showed that diffusion coefficients of the five SFEF cuts decreased as the experiment proceeded, which illustrates that these cuts are polydisperse in size. The effective diffusion coefficients varied with molecular size and pore size. Hindered diffusion of the five SFEF cuts is significant in the membranes with nominal pore diameter of 15 nm, which is around the average pore size of typical hydrotreating catalyst. Comparisons between experimental data and theoretical prediction revealed that the actual hindered degree for diffusion of the five SFEF cuts is higher than that calculated by the Renkin equation. There were slight differences in diffusivity among saturate, aromatic, and resin constituents. © 2010 American Institute of Chemical Engineers AIChE J, 2010
Gas‐solid flow distribution through identical vertical passages: Modeling and stability analysis
Authors: Masnadi Mohammad S. , Elyasi Siamak , Grace John R. , Bi Xiaotao
Published: January 2010

As previous evidence shows, the distribution of gas‐solid flow traveling through identical parallel paths can be significantly nonuniform, often with harmful operating consequences in practice. A fundamental analytical and numerical study is performed on the distribution of gas‐solid pneumatic flow passing through a “Y branch”. While many steady‐state gas‐solid distribution solutions, including a uniform distribution, satisfy the governing equations, linear stability analysis indicates that the uniform distribution is stable the most likely solution of the system. Both 2‐D (two‐dimensional) and 3‐D multiphase computational fluid dynamic simulations and stability analyses confirm the analytical conclusions. © 2010 American Institute of Chemical Engineers AIChE J, 2010
Evaluation of a fleet safety management information system
Authors: Newnam Sharon , Tay Richard
Published: January 2010

Despite recent interest in work related road safety, relatively little research has been conducted to examine the effects of institutional factors on fleet safety. This paper conceptualized an evaluation framework and utilized it to assess fleet coordinators' attitudes toward and the usage of a fleet safety management system. First, focus group interviews revealed that monitoring fleet safety was not considered an important task within the government agencies participating in the research. Second, similar results were obtained in a survey of the fleet coordinators, which showed that most fleet coordinators were not utilising the full diagnostic capabilities of the management information system. In particular, fleet coordinators reported significantly higher competence, usage and importance on the coordination of fleet vehicle efficiency than on the coordination of fleet safety. These results were supported by the finding that fleet coordinators were required to report more on fleet efficiency than on fleet safety.
Using a k‐means clustering algorithm to examine patterns of pedestrian involved crashes in Honolulu, Hawaii
Authors: Kim Karl , Yamashita Eric Y.
Published: January 2010

The purpose of this paper is twofold: 1) to describe a statistical technique known as K‐means clustering in term of its advantages and disadvantages in safety research; and, 2) to use this method to analyze spatial patterns of pedestrian‐involved crashes in Honolulu. K‐means, a partitioning clustering technique, provides a powerful tool for analyzing and visualizing spatial patterns. While there are other techniques, one of the advantages of the K‐means approach is that it is a well established technique that has been used for many different applications other than traffic safety. In this paper, we compare it to hierarchical clustering techniques and suggest that both are useful in the arsenal of spatial analytic tools for safety research.
Quantitative analysis of passenger and baggage security screening at airports
Authors: de Barros Alexandre G. , Tomber David D.
Published: January 2010

The terrorist attacks in the United States in 2001 opened a new era in air transportation. The realization that civil aircraft can be used as powerful weapons of mass destruction by a small group of people has drastically increased the need for security screening procedures to protect civil flights. Serving as the interface between the air and land transportation modes, airports have become the main focus in the implementation of those procedures. The need to more thoroughly screen passengers and baggage, and the consequent increase in processing time, has created the need for more space for security checkpoints and baggage screening inside passenger terminal buildings—space that is costly and very difficult to find in existing buildings. This paper evaluates the impact those measures have had on the planning and operation of airport passenger terminals. Quantification of those impacts is performed with the use of discrete‐event simulation and spreadsheet models.
An algorithm for finding reasonable paths in transit networks
Authors: Tan Man‐chun , Tong C. O. , Wong S. C. , Xu Jian‐min
Published: January 2010

In this paper, reasonable paths in transit networks are defined as possible paths that satisfy the acceptable time criterion and transfer‐walk criterion. A recursive algorithm for finding all of the reasonable paths in a transit network that does not involve a rapid increase in program run‐time with network size is presented. Realistic transit networks in Hong Kong and Guangzhou were selected as case studies of the different phases of the development of a trip planning system. Transport planning practitioners and potential users were invited to test the system to evaluate its performance. The results of the prototype evaluation were satisfactory, and the viability of the system as a useful tool for supporting decision‐making has been confirmed by the positive feedback that was obtained from survey questionnaires.
Partition‐based algorithm for estimating transportation network reliability with dependent link failures
Authors: Sumalee Agachai , Watling David P.
Published: January 2010

Evaluating the reliability of a transportation network often involves an intensive simulation exercise to randomly generate and evaluate different possible network states. This paper proposes an algorithm to approximate the network reliability which minimizes the use of such simulation procedure. The algorithm will dissect and classify the network states into reliable, unreliable, and un‐determined partitions. By postulating the monotone property of the reliability function, each reliable and/or unreliable state can be used to determine a number of other reliable and/or unreliable states without evaluating all of them with an equilibrium assignment procedure. The paper also proposes the cause‐based failure framework for representing dependent link degradation probabilities. The algorithm and framework proposed are tested with a medium size test network to illustrate the performance of the algorithm.
An integrated multi‐objective model to determine the optimal rescue path and traffic controlled arcs for disaster relief operations under uncertainty environments
Authors: Chiou Yu‐Chiun , Lai Yu‐Hsuan
Published: January 2010

This study proposes an integrated multi‐objective model to determine the optimal rescue path and traffic controlled arcs for disaster relief operations under uncertainty environments. The model consists of three sub‐models: rescue shortest path model, post‐disaster traffic assignment model, and traffic controlled arcs selection model to minimize four objectives: travel time of rescue path, total detour travel time, number of unconnected trips of non‐victims, and number of police officers required. Since these sub‐models are inter‐related with each other, they are solved simultaneously. This study employs genetic algorithms incorporated with traffic assignment and K‐shortest path methods to determine optimal rescue path and controlled arcs. To cope with uncertain information associated with the damaged network, fuzzy system reliability theory (weakest t‐norm method) is used to measure the access reliability of rescue path. To investigate the validity and applicability of the proposed model, studies on an exemplified case and a field case of Chi‐Chi earthquake in Taiwan are conducted. The performances of three rescue strategies: without traffic control, selective traffic control (i.e. the proposed model) and absolute traffic control are compared. The results show that the proposed model can maintain the efficiency of rescue activity with minimal impact to ordinary trips and number of police officers required.
Development of a sensor system for traffic data collection
Authors: Atluri Mahesh , Chowdhury Mashrur , Kanhere Neeraj , Fries Ryan , Sarasua Wayne , Ogle Jennifer
Published: January 2010

Although many types of traffic sensors are currently in use, all have some drawbacks, and widespread deployment of such sensor systems has been difficult due to high costs. Due to these deficiencies, there is a need to design and evaluate a low cost sensor system that measures both vehicle speed and counts. Fulfilling this need is the primary objective of this research. Compared to the many existing infrared‐based concepts that have been developed for traffic data collection, the proposed method uses a transmission‐based type of optical sensor rather than a reflection‐based type. Vehicles passing between sensors block transmission of the infrared signal, thus indicating the presence of a vehicle. Vehicle speeds are then determined using the known distance between multiple pairs of sensors. A prototype of the sensor system, which uses laser diode and photo detector pairs with the laser directly projected onto the photo detector, was first developed and tested in the laboratory. Subsequently this experimental prototype was implemented for field testing. The traffic flow data collected were compared to manually collected vehicle speed and traffic counts and a statistical analysis was done to evaluate the accuracy of the sensor system. The analysis found no significant difference between the data generated by the sensor system and the data collected manually at a 95% confidence interval. However, the testing scenarios were limited and so further analysis is necessary to determine the applicability in more congested urban areas. The proposed sensor system, with its simple technology and low cost, will be suitable for saturated deployment to form a densely distributed sensor network and can provide unique support for efficient traffic incident management. Additionally, because it may be quickly installed in the field without the need of elaborate fixtures, it may be deployed for use in temporary traffic management applications such as traffic management in road work zones or during special events.