bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue Crack Growth Rate Analysis in a Titanium Alloy
Authors: Korsunsky Alexander M. , Dini Daniele , Walsh Michael J.
Published: March 2009

Reliable prediction of fatigue crack growth rates in aerospace materials and components underpins the so-called defect-tolerant approach to lifing. In this methodology the presence or appearance of defects and cracks in components is accepted. However, safe operation is guaranteed by regular inspections and health monitoring, and ensuring (by means of reliable modelling) that no crack may grow far enough to reach the critical size in the interval between inspections. Under such circumstances it is clear that particular attention has to be paid to the development and validation of predictive modelling capabilities for fatigue crack propagation. The situation is complicated by the fact that it is often a challenge to represent correctly the in-service loading experienced by a cracked component. In practice, on top of the major cycles associated with each flight (LCF component), cycles of higher frequency and lower amplitude are also present (HCF component). Sensitivity to dwell at maximum load is also often observed. Furthermore, it is well established that complex load sequences involving overloads and underloads result in fluctuations of fatigue crack growth rates (retardation and acceleration) that must be accounted for in crack growth calculations. In the present study we consider the application of an approach due to Noroozi et al. [1] to the analysis of R-ratio effects in Ti-6Al-4V material, on the basis of the experimental crack growth rate data collected under the auspices of AGARD programme [2]. The approach shows promising results, and has the capacity to capture loading sequence effects.
Application of Artificial Neural Network to Forecast the Tensile Fatigue Life of Carbon Material
Authors: Liao Xiao Ling , Xu Wen Feng , Gao Zhi Qiang
Published: March 2009

Artificial neural network (ANN) is widely applied to the modeling of complex
systems, which has become a common modeling method in the study of materials science. As
the ideal candidates for high temperature structural materials, carbon materials are no doubt
involved in fatigue loads, so the study on forecasting fatigue life is meaningful. In this paper, the
electrical resistance at various fatigue cycles and level of applied stress of the materials under
tensile fatigue loading has been detected, and regarded the fracture or fatigue cycles equal to 106
as fatigue life of carbon materials. On the basis of the electrical resistance value, the fatigue life
has been forecasted by applied the ANN. The results indicated that the ANN could forecast the
fatigue life of carbon materials well; finally, the applications of ANN in the study of material,
such as properties prediction, damage prediction and failure detection were reviewed.
Mechanical Property of Porous Titanium Produced by Spark Plasma Sintering
Authors: Sakamoto Yuki , Moriyama Shigeaki , Endo Masahiro , Kawakami Yuji
Published: March 2009

Titanium has widely been used as a biomaterial because of its excellent corrosion
resistance and biocompatibility. However, problems with respect to biological reaction and fitness of
elastic modulus for human bone or tooth have yet to be solved. Porous titanium is expected to be a
promising material to solve these problems. The aim of this study is to clarify the effect of the porous
structure of this material on the biomechanical compatibility. The spherical pure titanium powder,
with an average particle size of 100 µm, was sintered by spark plasma sintering. The sintered porous
titanium compacts had a porosity of 33 %. The specimens were machined from the sintered compacts
for the evaluation of the mechanical properties. The elastic modulus indicated a value close to human
bone, while the tensile and compressive strengths showed lower values than those of human bone.
An Experimental Study on the Application of Cathodic Protection Method Applying Zn-Al Metal Spray on the RC Structure
Authors: Han Man Hae , Lee Han Seung
Published: March 2009

Cathodic Protection Method was introduced as a corrosion protection method of metals under the ground or sea. Since 1970, it was applied to corrosion protection method of reinforced concrete structures. After 1990, this method has been used around the world, and its usability was proved. But this method has some problems on the aspect of construction and economy. In order to solve these problems, Cathodic Protection Method by using high durable metal spray was developed. First, the specimen was covered with anodic materials (Zn, Al) by using metal spray. And a performance of corrosion protection was confirmed by measuring corrosion current and halfcell potential of specimen. Through the result of experiment, it is possible to know that Cathodic Protection Method by using high metal spray is good protect to corrosion on reinforced concrete structures.
Patterning of HfO2 Thin Films Using Chemical Solution and Dielectric Properties
Authors: Suzuki Kazuyuki , Kato Kazumi
Published: March 2009

HfO2 precursor solutions were prepared by modification of alkoxide for patterning of HfO2 films.
The HfO2 dots were patterned on Si substrate by inkjet printing method. The electrical properties of
HfO2 films prepared by inkjet printing method were almost same as the properties of the HfO2 films
prepared by spin-coating method. Additionally, the HfO2 nanostructures were successfully patterned
by nanoimprint method using the chemically-modified alkoxy-derived precursor solution.
Crystallization Behavior of BaO-TiO2-GeO2  Glass Thin Film
Authors: Ogawa Ryoh , Masai Hirokazu , Takahashi Yoshihiro , Mori Hiroshi , Fujiwara Takumi , Komatsu Takayuki
Published: March 2009

Crystallization behavior of the fresnoite-type Ba2TiGe2O8 (BTG) with a large optical nonlinearity
has been examined in the BaO-TiO2-GeO2 glass thin film fabricated by a RF sputtering technique and
the corresponding glass (same composition of thin film, i.e., 28BaO-22TiO2-50GeO2). Both the glass
thin film and the corresponding glass were crystallized by the heat-treatment, keeping a good
transparency. Initial formation of BTG phase followed by the BaGe4O9 phase was confirmed in the
both glass samples. In addition, the BTG crystallites in the both glass samples indicated the preferential
(211) orientation. Crystallization behavior confirmed in this study was quite different from the previous
study about the 30BaO-15TiO2-55GeO2 glass.
Preparation of (Ba, Sr)TiO3 Thin Films on Glazed Alumina Substrate and Analysis of their Electric Properties
Authors: Nozaka Takashi , Mizutani Yoji , Gun Bhakdisongkhram , Tsuchikawa Takuya , Echizen Masahiro , Nishida Takashi , Takeda Hiroaki , Uchiyama Kiyoshi , Shiosaki Tadashi
Published: March 2009

The (Ba0.6Sr0.4)TiO3 (BST) thin films were formed on a Pt bottom electrode/glazed-Al2O3 substrates by a chemical solution deposition (CSD) method. The BST films were annealed at temperatures between 600 and 800°C in a rapid thermal annealing (RTA) process and grown at each temperature with a random orientation. The grain size of the BST films enlarged and the electrical properties of the BST films improved as the annealing temperature rose. The grain size of the film annealed at 800°C enlarged to be 80 nm. The averaged surface roughness Ra was 2.927 nm, which resulted in a favorable degree of planarity. The dielectric constant and loss tangent of the film at 1 MHz were 403 and 0.049, respectively. The film also displayed a high degree of tunability, which was 58.3% (at 429 kV/cm). These results indicated that high-quality BST thin films could be formed on an extremely cheap glazed-Al2O3 substrates.
Fabrication of Titanate Thin Film by Electrophoretic Deposition of Tetratitanate Nanosheets for Electrodes of Li-Ion Battery
Authors: Suzuki Shinya , Sakai Naoko , Miyayama Masaru
Published: March 2009

Thin films of titanate were prepared by electrophoretic deposition (EPD) of a colloidal suspension
of nanosheets, and their lithium intercalation properties were examined. Thickness of the obtained
film increased approximately in proportion to the increase in deposition time and concentration of
the colloidal suspension used for EPD bath. EPD method was revealed to be a convenient method
for layer lamination of nanosheets. The reversible capacity for the obtained film was approximately
170 mA h g-1, and it was in common with anatase-type TiO2 or conventional titanate. Lithium
diffusion coefficient along the thickness direction was estimated to be 6 × 10-14 cm2 sec-1.
Fabrication of High-Aspect Ratio Micro Holes on Hard Brittle Materials -Study on Electrorheological Fluid-Assisted Micro Ultrasonic Machining-
Authors: Tateishi T. , Yoshihara Nobuhito , Yan Ji Wang , Kuriyagawa Tsunemoto
Published: March 2009

Ultrasonic machining (USM) is an effective method for machining of hard brittle
materials. In this process, the slurry is supplied to the gap between the workpiece and the ultrasonic
vibrating tool, and the materials are removed by the impacts of the abrasive grains that are
pressurized by an ultrasonic vibrating tool. The purpose of this research is to achieve precise and
efficient microfabrication on hard brittle materials by USM. However, in the case of
microfabrication, chipping which is generally observed around the edges of machined micro holes
and grooves, deteriorates the machining accuracy. In addition, there is another problem in that the
machining efficiency decreases with the progress of the machining. Electrorheological
fluid-assisted USM has been proposed as a countermeasure to these problems. In the present study,
the problems and countermeasures associated with the machining of high-aspect ratio micro holes
in hard brittle materials by electrorheological fluid-assisted USM are investigated. By positioning
an auxiliary electrode under the workpiece, it becomes possible to keep the electric field high even
when the machining depth becomes large. As a result, high-precision and high-aspect ratio micro
holes can be machined on hard brittle materials.
Fundamental Study on Influence of Surface Topography on Photocatalytic Reaction
Authors: Azusawa Keisuke , Ishii Yuta , Shimizu Jun , Zhou Li Bo , Eda Hiroshi
Published: March 2009

TiO2 has some unique photocatalytic functions and some of them have been utilized
industrially, and further functional enhancement and performance enhancement of TiO2 have been
required. Under such circumstances, this study aims to clarify the influence of surface topography on
the photocatalytic reaction of TiO2 film surface. As the first step, the optimum mixing ratio in film
preparation by using TiO2 powder was examined and the films with several kinds of surface
roughnesses were prepared. And, the influence of surface topography on the wettabilty, which is one
of the photocatalytic functions of TiO2 was evaluated. As a result, it was confirmed that the
wettability of TiO2 films could be improved by increasing both the surface roughness and actual
surface area under the ultraviolet rays irradiation environment.
Material Removal Mechanism of Chemo-Mechanical Grinding (CMG) of Si Wafer by Using Soft Abrasive Grinding Wheel (SAGW)
Authors: Guo Dong Ming , Tian Y.B. , Kang Ren Ke , Zhou Li Bo , Lei M.K.
Published: March 2009

An innovative fixed abrasive grinding process of chemo-mechanical grinding (CMG) by using soft abrasive grinding wheel (SAGW) has been recently proposed to achieve a damage-free ground workpiece surface. The basic principle, ideas and characteristics of CMG with SAGW are briefly introduced in this paper. The CMG experiments using newly developed SAGW for Si wafer are conducted at the condition of dry grinding. The grinding performances are evaluated and analyzed in terms of surface roughness, surface topography and surface/subsurface damage of ground wafer by use of Zygo interferometer, Scan Introduction ning Electron Microscope (SEM) and Cross-section Transmission Electron Microscope (Cross-section TEM). The component of product of ground Si surface is studied by X-ray Photoelectron Spectroscopy (XPS) to verify chemical reaction between the abrasive / additives of grinding wheel and Si wafer. The CMG process model by using SAGW is developed to understand the material removal mechanism and generation principle of damage-free surface. The study results show that the material removal mechanism of CMG by using SAGW can be explained as a hybrid process of chemical and mechanical action.
Observation of Abrasive Grains Behavior in Contact Area of Grinding Wheel and Comparison with Grinding Wheel Model
Authors: Yamada Taisei , Lee Hwa Soo
Published: March 2009

In contact areas between grinding wheels and workpieces, elastic deformations of grinding
wheel take place due to the act of grinding forces. Since grinding wheels consist of abrasive grains
and bonds, it may be regarded that the elastic deformations of grinding wheels in contact areas depend
on movements of each abrasive grain. However, plural grains are connected each other complicatedly,
and then it is difficult to observe each grain behavior. This study aims to directly observe the
behaviors of grains in contact areas with workpieces. A small loading apparatus for grinding wheel is
newly developed. Inserting a loaded wheel with this apparatus into SEM, grains behaviors in contact
area are directly observed. Furthermore, grains behaviors under loaded condition are analyzed with a
wheel model developed previously and observed results are compared with analyzed results.
Achieving a Damage-Free Polishing of Mono-Crystalline Silicon
Authors: Biddut A.Q. , Zhang Liang Chi , Ali Y.M. , Liu Zong Wen
Published: March 2009

This paper experimentally investigates the micro-structural changes in mono-crystalline silicon induced by abrasive polishing with abrasive grain size and applied pressure. It was found that while the large abrasives of about 15 μm and 300 nm in diameter induce both residual amorphous phase and various residual crystalline structures and dislocations, the finer abrasives of about 50 nm in diameter only produce residual amorphous phase in the top subsurface of polished silicon. With the fine abrasives, reducing applied pressure reduces the amorphous layer thickness, and a damage-free polishing can be achieved at the pressure of 20 kPa.
Progress on Nanoceramics by Sol Gel Process
Authors: Chen Quan , Soutar Andrew M.
Published: March 2009

Sol-gel technology has been proved as a very valuable tool for producing and processing
ceramic materials for advanced applications especially when currently nanotechnology becomes as
the dominant topic for most of the scientists and engineers. While many functional ceramic
materials are of technological interest, this paper tries to give an over view of recent progress in
synthesis of ceramic powders, mainly nano-scaled powders, by sol gel process and their
applications.
Application of Partial Least Squares Neural Network in Thermal Error Modeling for CNC Machine Tool
Authors: Shen J.H. , Yang Jian Guo
Published: March 2009

This paper presents a partial least squares neural network modeling method for CNC
machine tool thermal errors. This method uses the neural network learning rule to obtain the PLS
parameters instead of the traditional linear method in partial least squares regression so as to
overcome the multicollinearity and nonlinearity problem in thermal error modeling. The basic
principle and architecture of PLSNN is described and the new method is applied on the thermal error
modeling for a CNC turning center. After model validation with two groups of new testing data and
performance comparison with other five different modeling methods, PLSNN performs better than
the others with better robustness.
A Formal Verification for Web Service Composition Based on CCS
Authors: Yun B.S. , Yan J.W. , Liu M.
Published: March 2009

Web service composition is a complex and error-prone process. To guarantee its correctness, CCS is exploited as a formal tool to model Web service composition. Composition algebra is defined to specify the rules through which a compositive service can be generated. The transformation mechanisms from service compositions into CCS formalisms according to their corresponding composition operators are gone into details. Then, the automatic reasoner CWB is used to validate the constructed model, by which the dynamic behaviors of the model can be verified and such composition errors as deadlocks can be detected in advance, thus enhancing the composition reliability and avoiding runtime failure. Finally, an example is given to illustrate the effectiveness of this approach.
Material Removal Model and Numerical Analysis of Fluid Magnetic Abrasives Finishing
Authors: Sun Huan Wu , Yang Shi Chun
Published: March 2009

The fluid magnetic abrasives (FMA) are a new type of precision finishing abrasives,
which can be used to finish the work-pieces with intricate or complex shape to a quite low surface
roughness value. As a key parameter, the material removal rate has a great impact on the finishing
capabilities and the final surface roughness. In order to get a better understand of FMA removal
mechanism, the numerical analyses was used to simulate the shearing stress field and velocity
distribution. The experimental results are discussed as well in this paper.
Study on Location Simulation for Picking Manipulator in Virtual Environment Based on Information Fusion of Multi-Sensor
Authors: Wang Hong Jun , Zou Xiang Jun , Zou D.J. , Liu J. , Liu Tian Hu
Published: March 2009

In picking manipulator location system, it is the key problem that the positions of
obi-object and picking manipulator are exactly determined in complex environment. Based on
multi-sensor information fusion method, a data fusion system of multi-sensor integrating laser-sensor
for absolute location with ultrasonic-sensor for inspection impediment was presented. Firstly, data
collection and fusion were implemented employing a two- level distribution system. Secondly, the
method of data collection and fusion in virtual environment was discussed, and the result data could
drive picking manipulator 3D model to dynamically move in real-time using event and route
mechanisms provided by virtual environment, which could simulate the process of picking
manipulator being accurately located. Finally, a location simulation system was developed by VC++
and EON SDK.
An Open Architecture Control System for Parallel Kinematic Machines Based on Multi-DSP Parallel Procession
Authors: Wang Hui , Ni Y.B. , Li K.
Published: March 2009

Because of the control complexity of the Parallel Kinematic Machines (PKMs), such
mechanisms may suffer from lack of accuracy at high speed. Unfortunately, conventional motion
controllers have very limited flexibility because they are designed for Cartesian coordinates.
Therefore, the motion control system for PKMs with both high performance and open architecture
is urgently demanded. In this paper, an open architecture control system for PKMs based on
multi-DSP parallel procession is presented. Then, the hierarchical distributed control strategy is
discussed in details. In addition, the realization of an interactive communication interface among
DSP processors is presented. According to the testing results, the developed system is capable of
obtaining an interpolation sampling period at least 3 times faster than that could be offered by most
controllers based on single-DSP, thus it is available for high-speed and high-accuracy control of
PKMs.
Study on Fuzzy-Neural Network for Inverted Plasma Arc Cutting Power Supply
Authors: You Bo , Jia De Li , Zhang Feng Jing
Published: March 2009

A variable interval fuzzy quantification algorithm with self-adjustable factor in full domain is proposed in this paper. It focuses on digital inverted plasma arc cutting power and studies strong nonlinearity and uncertainty of power. The neural network is also introduced to decouple cutting parameters variables in the multi-parameters coupling cutting process. This algorithm avoids complex nonlinear system modeling and realizes real-time and effective online control of cutting process by combining advantages of fuzzy control and neural network control. Furthermore, the optimized fuzzy control improves steady-state precision and dynamic performance of system simultaneously. The experimental result shows that this control improves precision, ripples, finish and other comprehensive index of work piece cut, and plasma arc cutting power supply based on fuzzy-neural network has excellent control performance.
Study on Automatic Assembly Design of Product Based on UG
Authors: Hu Qing Xi , Xu Yan Zhi , Lu Q.
Published: March 2009

In the automatic assembly of product, the key steps are to automatically get constraint
objects and plan the assembly path. For the assembly module of UG, the constraint object is not to
be gotten automatically, and the assembly path is planned manually. The algorithm to automatically
get object occurrences is proposed to plan the assembly path, and the limitation problem of the
existing automatic assembly is solved too. The automatic assembly module is developed in UG by
adopting the further development tools. This software can implement the automatic assembly of
rapid fixture. The feasibility of the proposed method is verified by operating the typical example in
the software.
Adaptive Ant Colony Algorithm Used in WSNs Routing for Information Acquisition of Manufacturing Process
Authors: Wang G.T. , Ning Jing , Wu L.M.
Published: March 2009

Ant colony algorithm (ACA) is employed and improved in routing protocol of information acquisition of manufacturing process based on wireless networks. Weighting factor for paths selection is defined as an exponential variable in adaptive ACA. In this way, it prevents the weighting factor from excess increasing or rapid reducing to 0 which results in local optimum. This approach can dynamically adjust paths selection and improve global search ability by optimizing global policy. Adaptive ACA consumes the least time in the process of searching the most optimized paths and searches the shortest paths under the same of iterative loops. Under the same condition of the information heuristic factor and the expected heuristic factor, the algorithm shows good adaptation, realizes the load balancing between paths and resolves the dynamic adjustment problem.
Study of Morphology of Cardiac Valves (Human and Bovine Pericardium) after In Vivo Calcification
Authors: Nogueira Grínia M. , Aimoli Cassiano Gomes , Weska Raquel Farias , Leirner Adolfo A. , Maizato Marina J.S. , Higa Olga Z. , Polakiewicz Bronislaw , Pitombo Ronaldo N.M. , Beppu Marisa Masumi
Published: March 2009

Pathologic calcification can lead to failure or deterioration of cardiac valves. Several researchers have tried alternatives to construct these devices, such as the incorporation or utilization of new biomaterials able to inhibit or decrease the calcification process. In vitro calcification tests can be used to screen new biomaterials regarding their potential to calcify in vivo. However, the mechanisms involved in both cases are not completely understood. In order to collect more information about the calcification process of implanted materials, morphology and elemental analyses of calcified cardiac valve fragments explanted from different patients were investigated and compared to previous reports of in vitro calcification tests. Scanning Electron Microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses indicated that the calcium phosphate deposits from both bovine pericardium and human cardiac valves calcified in vivo were similar to the deposits obtained from in vitro calcification samples as previously reported in the literature.
Amorphous Calcium Polyphosphate Bone Regenerative Materials Based on Calcium Phosphate Glass
Authors: Lee Byung Hyun , Kim Min Chul , Choi Seong Ho , Lee Yong Keun
Published: March 2009

We developed new calcium phosphate bone substitute material, amorphous calcium polyphosphate. The new material is synthesized by a cement-like slif-setting reaction with calcium phosphate glass, basic materials and water. In this study, we prepared with CPG, Na2CO3 and NaOH solution. When they are mixed together, amorphous phase was precipitated. The precipitated amorphous phase consisted of polyphosphate chains condensed with Na ions released from Na2CO3 and NaOH. When the amorphous calcium polyphosphate dissolves, inorganic polyphosphates are released into the medium. The inorganic polyphosphates as the dissolution product inducted the calcification of the osteoblast cells. Therefore, in animal test, the new bone formation in rat calvarial defects treated with the new material was significantly higher than sham-surgery control group, especially in the initial stage. The amorphous calcium polyphosphate was biocompatible and bioresorbable and promoted the new bone formation.
Elastic Modulus and Hardness of Bioactive Ti Obtained by Anodic Oxidation Using Ca/P-Based Solutions
Authors: de Souza Gelson B. , de Lima Gabriel G. , Kuromoto Neide K. , Soares Paulo , Marino Cláudia E. B. , Lepienski Carlos M.
Published: March 2009

Anodic oxidation is a promising technique to become titanium surfaces bioactive, by simultaneously changing the surface morphology, structure and chemical properties. Calcium and phosphorus based electrolytes were used to produce anodic films on c.p. Ti with two different current densities, 150 mA/cm2 and 300 mA/cm2. Morphology and structure were examined by SEM, EDS and XRD, and elastic modulus and hardness of the surfaces by instrumented indentation. Besides rutile and anatase TiO2 phases, hydroxyapatite was also identified on the films, as well as the segregation of very soft Ca and P-rich zones. Low values for the elastic modulus and hardness values close to the Ti corroborate to the applicability of Ca and P based TiO2 anodic films in biomedical titanium implants.
Mechanical Properties of Anti-Infectious, Bio-Active and Wear Resistant Ceramic Implant Surface Coatings
Authors: Fritsche Andreas , Heidenau Frank , Neumann Hans Georg , Mittelmeier Wolfram , Bader Rainer
Published: March 2009

Implant failure due to aseptic loosening is a major complication in total hip arthroplasty. Different implant coatings aim to reduce the risk of implant loosening by anti-infectious, bio-active or wear resistant approaches. The mechanical properties, especially bonding strength and wear resistance, of a Cu-TiO2, CaP and TiN coating were investigated in this study. A scratch test and a standard adhesive test were used to determine the bonding strength of the coatings. To analyse the wear resistance a modified special testing machine was used to evaluate wear with PU-foam and PMMA as counterparts. The investigations showed that all coatings have greater bonding strengths than the minimum required 22 N/mm2 for medical implant coatings. Significant differences in total wear were determined during the wear tests. With the exception of the CaP no removal of the coatings was detected.
In Vitro Osteoclast Differentiation of Bone Marrow Cells on Hydroxyapatite/Collagen Self-Organized Bone-Like Nanocomposite Disk
Authors: Kikuchi Masanori , Irie Atsushi
Published: March 2009

Osteoclast differentiation of bone marrow cells on hydroxyapatite/collagen self-organized bone-like nanocomposite (HAp/Col) disk in vitro was evaluated by coculture of mouse bone marrow cells with mouse osteoblasts with or without addition of osteoclastic inducers, 1,25-Dihydroxyvitamin D3 and 1 µM prostaglandin E2. Dentine slice and tissue culture polystyrene were used as controls. Good osteoclastic differentiation at day 7 were observed among the bone marrow cells cultured on the HAp /Col disk and controls with osteoclastic inducers. On the contrary, osteoclastic differentiation was observed only for marrow cells cultured on the HAp/Col disk. Nano- and micro- structures as well as chemical and mechanical properties have a potential to control cell differentiation.
The Release and Bioactivity of Lysozyme from Selected Sol-Gel Derived SiO2 Matrices
Authors: Wilson Timothy , Viitala Reeta , Puska Mervi , Jalonen Harry , Penttinen Risto , Jokinen Mika
Published: March 2009

Local drug release has many benefits – a steadier distribution, improved compliance, but most importantly it allows the convenient use of protein based molecules as therapeutic agents. Many different types of materials have been studied as drug carriers, including sol-gel derived SiO2 matrices. In this study lysozyme was used as a model protein and its release from prepared SiO2 monoliths and its biological activity thereafter was studied spectroscopically. Sucrose was used in some preparations to assess its ability to function as a protective agent during storing. Lysozyme release and bioactivity was similar in both preparations containing it when tested fresh. In monoliths stored for ten weeks, however, differences were observed in the biological activity of released lysozyme. In the preparations containing sucrose, lysozyme had retained its activity, while it was virtually nil in the preparations containing only lysozyme. This shows that sol-gel derived SiO2 matrices can be used as carriers for small proteins and that sucrose can function as a protective agent in them.
A Pull-Shear Test for Debonding of FRP- Laminates for Concrete Structures
Authors: Gil Lluis , Cruz Juan José , Pérez Marco Antonio
Published: March 2009

The reinforcement of concrete structures with laminates of carbon fibers CFRP (Carbon Fiber Reinforced Polymer) began in the 1970’s but laminates were not used extensively until the 1990’s.Nowadays it is one of the most promising technologies due to the good mechanical characteristics of the laminates and their easy manipulation. In the near future, laminates will play a fundamental role in the rehabilitation projects of buildings. Laminates bond to the concrete by means of resins of epoxy type. The capability of the reinforcement depends directly on the proper behavior of the interface laminate-concrete. The laminate helps to bear loads while the concrete is able to transfer stresses to the laminate. The safety factor of the reinforcement can be guaranteed if we can predict the behavior at the interface between both materials. In this work a test of pure shear has been developed to better understand the behavior at the interface between the laminate and the concrete.
Fractal Analysis of Fracture Surfaces of Steel Charpy Specimens
Authors: Secrieru Claudia , Dumitru Ion
Published: March 2009

The article focuses on the technical measurements which could be applied to the fracture
surfaces of the steel Charpy specimens in order to apply the Fractal Analysis. One could calculate the fractal dimension not directly for a fracture, but for a profile of the fracture. Most common methods for generation of fracture profile are cross-cut techniques and profile measurements techniques [1-2]. We apply three principal methods: Profilometer, Interferometer Light Microscope and the Vertical Section for a specimen made of XC65 after the Charpy test. We compare the advantages and the limits for each technique. We use the Box Counting algorithm applied in the Image J program for determining the fractal dimension of the fracture surface in all three experimental techniques. Then we could characterize the roughness of the fracture profile at different magnifying power by the estimated fractal dimension.
The Assessment of Remaining Life of Chemical Reactor Exposed to Creep and Fatigue
Authors: Mateiu Horia , Fleşer Traian , Murariu Alin Constantin
Published: March 2009

The paper presents an application according the reliability and remining life assessment of the reactor (coxing box) from a petrochemical plant, after failure in welding joint of plated shell from W1.5423 (16Mo5) steel with 25 mm thickness, plated with W1.4002 stainless steel with 3 mm thickness. The reactor failure it has associated with initial flaws from welding process, which have accelerated remaining life exhaustion. The assessment made in two steps. It has used VII section of ASME code specifications and iRiS-Thermo expert system for preliminary remaining life assessment. Concomitantly, it was performed the experimental creep and thermal fatigue testing.
The program results have defined creep and thermal fatigue exhaustion and its remaining life at common creep-fatigue action, in condition of safety exploitation. It was emphasized the possibility of use an extra 40,000 hours of rehabilitated reactor in the safety condition of normal parameters.
Damage Detection of Concrete Structures Using Acoustic Emission
Authors: Nair A. , Cai C.S.
Published: March 2009

The current state of bridges in the United States calls for the implementation of a continuous bridge monitoring system that can aid in timely damage detection and help extend the service life of these structures. A typical monitoring system would be one which enables non-invasive, continuous monitoring of the structure. The passive nature of the acoustic emission (AE) evaluation technique makes it an ideal choice to serve this purpose. Although the technique has been successfully used for decades for damage detection in other fields, its potential in bridge monitoring has not yet been fully exploited. This paper presents experimental tests performed on four concrete beams in laboratory. The laboratory concrete beams were tested under different loading patterns. While acoustic emission monitoring of bridge structures is not a new vista, most evaluations conducted before are only qualitative. Though some quantitative methods have been proposed, they have not yet developed to be useful for actual field test of bridges. Therefore, an attempt was made in this study to use the intensity analysis technique for damage quantification. The use of intensity charts may help in better estimating the damage severity, although clearly marked zones of damage are not yet prescribed for certain materials like concrete and steel. All in all, the applications of AE in bridge monitoring reveal the potential of this technique’s versatility. The technological advances made in recent years have made the method more suitable for onsite monitoring situations. Although more research may be needed to implement the current ideas, the future looks promising for the application of this technology in efficient continuous bridge monitoring scenarios.
Theory and Practice of New Types of Long-Span Building Structures Developed at Guizhou University
Authors: Ma Ke Jian , Lu Y.Q. , Xiao J.C. , Zhang H.G.
Published: March 2009

This paper presents the theory and practice of new types of long-span building structures developed at Guizhou University for the recent 25 years. The new structural systems include RC open-web sandwich plate structures, steel/RC composite open-web sandwich plate structures, prestressed RC open-web sandwich plate structures, and cast-in-place concrete round eye hollow plate structures. The mechanical characters and technical indexes of each system are described. The application of the structures is detailed in tables and photos.
Modeling Cyclic Behavior of Reinforcing Steel: Relevance in Seismic Response Analysis of Reinforced Concrete Structures
Authors: Heo Yeong Ae , Zhang Guo Wei , Kunnath Sashi K. , Xiao Yan
Published: March 2009

In nonlinear dynamic analyses of RC structures based on fiber-based discretization of member cross-sections, the constitutive model used to represent the cyclic behavior of reinforcing steel typically plays a significant role in controlling the structural response especially for nonductile systems. The accuracy of a fiber-section model is almost entirely dependent on the ability of both the concrete and reinforcing steel constitutive material models to represent the overall inelastic behavior of the member. This paper describes observations related to the fundamental properties of reinforcing steel such as buckling, hardening, diminishing yield plateau and growth of curvature, Bauschinger effect, and low-cycle fatigue and strength degradation that are relevant to the overall task of developing an accurate material model for use in seismic response analysis of reinforced concrete structures.
Processing of High Performance Silicon Carbide
Authors: Hirata Yoshihiro , Matsunaga Naoki , Hidaka Nobuhiro , Tabata Shuhei , Sameshima Soichiro
Published: March 2009

Liquid phase sintering based on the dissolution-precipitation mechanism was applied to densify a 0.8 μm SiC powder with alumina (1.2 vol%)-yttria (0.9-3.3 vol%) additives. To uniformly distribute the sintering additives around the SiC particles, a heterocoagulated particle network was formed among negatively charged SiC particles, positively charged 0.2 μm alumina and yttrium ions in an aqueous suspension at pH 5. Yttrium ions were electrostatically adsorbed on the negatively charged SiC surfaces. The consolidated green compacts were highly sintered to 97-99 % of theoretical density by hot-pressing at 1950 °C. Four-point strength, fracture toughness and Weibull modulus were highly enhanced when a bimodal particle size system of SiC (75 vol% 0.8 micrometer-25 vol% 30 nanometer SiC) was sintered. The maximum strength reached 1.1 GPa. The fracture toughness was about 6 MPa•m1/2 and the Weibull modulus was 5.9. When a small amount of SiC precursor polymer was infiltrated in the green compact, the strength and Weibull modulus were further improved.
Spark Plasma Sintering of Silicon Nitride-Boron Carbide Composites
Authors: Ayas E. , Kalemtas A. , Arslan Gürsoy , Kara Alpagut , Kara Ferhat
Published: March 2009

Si3N4-B4C composites containing fine and coarse B4C particles were produced using Al2O3 and Y2O3 as sintering additives via spark plasma sintering (SPS) technique. Phase assemblages of the produced composites were determined by XRD analysis. Si3N4, B4C and in situ formed SiC, h-BN and Si phases were observed. Even when incorporated in significant amounts, B4C was consumed readily in the Si3N4 based system. Consequently, full densification of these composites was found to be a very difficult task due to the simultaneous in-situ reactions, even in fast sintering process. Electrical resistivity measurements carried out at room temperature indicated that addition of both fine and coarse B4C particles decreased the electrical resistivity by several orders of magnitude due to the formation of electrically conductive in-situ phases, mainly SiC and metallic Si.
Fabrication of AlN Ceramics Using AlN and Nano-Y2O3 Composite Particles Prepared by Mechanical Treatment
Authors: Hiratsuka Daisuke , Tatami Junichi , Wakihara Toru , Komeya Katsutoshi , Meguro Takeshi
Published: March 2009

AlN ceramics used in electronic substrates and packages are fabricated by the densification of green bodies with sintering aids such as rare-earth oxides. The homogeneous dispersion of the sintering aids, achieved with the help of the mechanochemical bonding of several types of fine powders, is the key process for obtaining a good sinterability and high performance. In this study, we fabricated the AlN ceramics using AlN and nano-Y2O3 composite particles prepared by mechanical treatment. The AlN powder and nano-Y2O3 powder were ball-milled with Al2O3 balls and a dispersant in ethanol in a plastic pot. The powder mixture of AlN and Y2O3 was composited by mechanical treatment. The composite powder was granulated and pressed to obtain a green body. After dewaxing, the AlN green body was fired at 1800°C in 0.6 MPa N2. The sintered body possessed a fracture toughness of 3.6 Pa•m1/2, higher than that, 3.1 Pa•m1/2, of the AlN ceramics fabricated without the mechanical treatment. An observation of the fractured surface revealed that grain boundary reinforcement enhances the fracture toughness of the AlN ceramics made of composite particles.
The Oxidation Behavior of ZrB2-Based Mixed Boride
Authors: Lee Seung Jun , Kim Do Kyung
Published: March 2009

Zirconium diboride based composites containing silicon carbide with relative densities in excess of 99 % were produced by hot-pressing. Oxidation test was conducted in air at 1500 °C. ZrB2-SiC composite showed relatively low oxidation resistance due to the non-uniform surface silica-rich layer. But in case of mixed boride-SiC composites further improvement of the oxidation performance were observed due to the phase separation in the surface silica-rich layer.
Electrical Resistivity Control of Hot-Pressed Aluminum Nitride Ceramics
Authors: Yamada Naohito , Yoshikawa Jun , Katsuda Yuji , Sakai Hiroaki
Published: March 2009

Aluminum Nitride (AlN) ceramics are used as wafer heating plates and wafer holding electrostatic chucks in semiconductor fabrication equipments. For tailoring the electrical resistivity to satisfy the requirements of each component, several kinds of approaches were investigated for hot-pressed AlN ceramics. Three techniques to control the electrical resistivity of AlN ceramics were adopted: (1) AlN intragranular control, (2) intergranular phase control and (3) incorporation of electrically conductive second phase particles. In this paper, we introduce examples of each technique. The first one is addition of a small amount of Y2O3. The resistivity varied from 1015 Ωcm to 1010 Ωcm with the Y2O3 amount. The second one is addition of Sm2O3. The resistivity also varied from 1015 Ωcm to 1010 Ωcm with the Sm2O3 amount. The third one is incorporation of in-situ synthesized Boron Carbonitride (B-C-N). Networking of B-C-N platelets drastically decreased the resistivity to the range less than 102 Ωcm. By these techniques, it was possible to control the resistivity of AlN ceramics in a wide range with a small amount of additives.
Thermal Conductivity Measurement of the AlN Ceramics at the Grain Scale Using Thermoreflectance Technique
Authors: Lee Sang Kee , Yamada Ikuko , Kume Shoichi , Nakano Hiromi , Watari Koji
Published: March 2009

The thermal conductivity at the micrometer-scale of AlN ceramics with eliminated grain boundary phase was measured by the thermoreflectance technique with periodic heating. Thermal conductivities were ranged from 160 to 260 W/m•K and an average value of 201 W/m•K was obtained from a 22 m2 area. The variation in the thermal conductivities was related to the individual AlN grains and grain boundary characteristics.
Polishing Performance of Electro-Rheological Fluid of Polymerized Liquid Crystal Contained Abrasive Grit
Authors: Tanaka Takeshi
Published: March 2009

In this study, we proposed an electro-rheological fluid-aided polisher (ERAP) using one-sided, patterned electrodes. The characteristics of ER fluid and ER fluid containing abrasive grit were investigated. The polishing performances of ER fluids with and without abrasive grit employing ERAP were verified and the following conclusions were obtained. Decreases in viscosity and in the ER effect were observed when highly polymerized liquid crystal (hereafter referred to as HPLC) was diluted with silicon oil. However, the mixing of abrasive grit increases the ER effect, but the ER effect of ER fluid containing abrasive grit decreased when mixed with abrasive grit. The viscosity decreased with increases in aliphatic saturated cyclic hydrocarbon oil (hereafter referred to as NCDM) mixed in highly polymerized compound (one kind of HPLC). The larger the positive dielectric anisotropy, the larger the ER effect in low-polymerized liquid crystal (hereafter referred to as LPLC). The smaller the grit size, the weaker the ER effect. When polished with HPLC, the polished surface was rough due to the large viscosity of an HPLC:silicon oil ratio of 4:14 mixed with #2000WA. However, the smallest surface roughness was attained at 0.5kV/mm for an HPLC:silicon oil ratio of 1:17 mixed with #2000WA. The surface quality was improved at an HPLC: silicon oil ratio of 1:17 mixed with #3000WA. When polished with LPLC, the surface roughness was improved by the increased ER effect when LPLC having a positive dielectric anisotropy was used. However, the surface roughness showed no change when LPLC with a negative dielectric anisotropy was used, due to its small ER effect.
Early-Age Heat Evolution and Pore Structure of Portland Cement Blended with Blast Furnace Slag, Fly Ash or Limestone Powder
Authors: Zhou Jie , Ye Guang , van Breugel Klaas
Published: March 2009

Recently, blast furnace slag, fly ash and limestone powder are increasingly used as blending materials in producing concrete. The use of these materials not only has economical and environmental advantages, but also improves the mechanical properties, durability and workability of concrete. In this paper, the results of experimental investigations on the evolution of hydration heat and the development of microstructure of Portland cement blended with blast furnace slag, fly ash or limestone powder are presented. These results show that three blending materials accelerate the hydration of Portland cement, but result in less heat release during the first 72 hours. The Portland cement with blast furnace slag has a denser pore structure than the others.
Effect of Inorganic Salts on Pore Structure of Cement Paste
Authors: Yang Wen Cui , Ge Yong , Yuan Jie , Zhang Bao Sheng
Published: March 2009

Inorganic salts are important admixtures usually used in cold weather concrete. As research basic of influence of salts on concrete durability, effects of inorganic salts on pore structure of cement paste were studied in this paper, and possible implications of concrete property with pore structure was also analyzed. Pore structure of paste added CaCl2, NaCl, Na2SO4, NaNO2, Ca(NO3)2 and Ca(NO2)2 curing for 3 days and 28 days were tested through mercury intrusion porosimetry (MIP). The results showed that no matter 0.3 or 0.5 water-cement ratio, the pores whose diameter <50nm in paste with salts increased at 3 days, which was harmful for the control of concrete shrinkage and cracking at early age. Adding Ca (NO3)2 increased coarse pores (>200nm) of paste at 3 days, but these coarse pores turned into fine pores and reduced significantly at 28 days. Adding NaCl and Na2SO4 into cement paste raised coarse pores with size>1000nm at 3 days and 28days, which were harmful for the pore structure.
Automating the Design of Cold Roll Forming Roll Sets
Authors: Mynors Diane J. , English Martin , Castellucci Michael
Published: March 2009

The design of cold roll forming roll tools, roll geometry and the number of tool sets, can typically be referred to as experiential design. Within a multi-occupant design office there will normally, for the same sectional profile, be as many different designs as there are designers. This variation in design results in a lack of design consistency and hence makes the process of developing design understanding, increasing profile complexity, maintaining quality, and roll tool predictability very difficult.
This paper contains an explanation of the approach taken within the Hadley Group to identify the discrete steps associated with roll tool set design. To implement methods to standardise these steps including strip width and clearance calculations. With appropriate design steps standardised an explanation is provided as to how elements of this design process is automated leading to a system of assisted design for roll tool sets.
The results, including increased design capacity, of the assisted roll design after being incorporated into the design office are discussed.