bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Fabric Structure on Shielding Effectiveness of Anti-Electromagnetic Radiation Fabric
Authors: Liu Jun Mei
Published: September 2014

In this paper, the standard test method of fabric shielding effectiveness was simply introduced in order to understand systematically the influence of fabric structure of stainless steel fiber on the shielding effectiveness. The different fabrics were woven using of stainless steel monofilament cotton yarn, stainless steel multifilament cotton yarn and stainless steel fiber cotton yarn. Then shielding effectiveness of these fabrics was measured. Results show that spacing between the stainless steel filaments has a great influence on the shielding effectiveness. The shielding effectiveness of fabric will reduce in a certain range when distance of stainless steel filaments is lengthened. Then shielding effectiveness of blended fabric will increase with increasing of the content of stainless steel fiber. The shielding effectiveness of duplex stainless steel filament fabrics is much better than unidirectional stainless steel filament fabric. Under the same testing condition the shielding effectiveness is different between stainless steel monofilament blended fabric and stainless steel multifilament blended fabric. The structure of stainless steel blended yarn has a great effect on shielding effectiveness of shielding fabric, the shielding effectiveness of stainless steel fiber blended fabric is better than the stainless steel filament blended fabric because the content of stainless steel fiber is difference between two kinds of yarn structure.
Application of Media Assets Management in TV Program Production
Authors: Zhang Yang
Published: September 2014

In the TV program production, the Media Assets Management system should have integration of production, material management, browsing, information management, friendly interface, standardized operation and open system and other functions. The MAM system consists of the Media Assets Management server, WEB application server, streaming media server, cataloging workstation and data streaming tape library. The MAM system in the Whole station network should be an extended full service platform to achieve unified management of various media assets automatically.
Preparation and Swelling Characteristics of Hydrogel from Microbial Low Molecular Weight Poly(γ-Glutamic Acid)
Authors: Zhang Yu Bo , Li Zheng , Zhang Jian Fei , Qiao Chang Sheng
Published: September 2014

In this paper, a novel low molecular weight poly (γ-glutamic acid) hydrogels were prepared by chemical method, and their preparation conditions such as poly (γ-glutamic acid) and crosslinker concentration, pH and temperature were studied. When poly (γ-glutamic acid) solution was 18%, pH 4.0, poly (γ-glutamic acid) was crosslinked to yield high water hydrogel with specific water content of 1328 times their dry volume depending on the preparation conditions.
The Influences of Slope and Slipperiness on Subjective Rating of MMH
Authors: Hsu Yao Wen , Chen Lieh
Published: September 2014

This study investigated the influence of slope and floor slipperiness on subjective rating of manual material handling (MMH), and identified the consistence between the subjective rating and objective measurement of floor slipperiness under various physical workloads. The COF measurements under slopes (0 ̊~10 ̊), three different floors and two surface conditions were conducted in this study. Thirty adults were recruited to carry four kinds of loads (0~15 kg) and walk on the slope. A survey was immediately conducted to obtain their rating of perceived exertion and perceived sense of slip while handling the loads. The results showed that the influences of gender, slopes, and loads on subjective ratings were significant statistically. The correlation between subjective rating and objective measurements of slipperiness was significantly high. Furthermore, the results also suggested that the floor materials should be selected to avoid the slip accidents. The limitations of slope and load also should be considered for different gender to prevent the disorders on the slopes for MMH tasks. As a result for obtaining the rating of perceived exertion, it was suggested that the combinations of slope angle and load are 5o and 15 kg for male and 5oand 10 kg for female.
The Identity and Design of Thai Tradition Paintings
Authors: Seviset Somchai , Louhapensang Chaturong
Published: September 2014

“Kranok” mostly are inspired by the application from natural shapes such as lotus shape, floral species, climber creeping plants or various animals especially animals in the fairy tales. “Kranok” which previously had the meaning of a Thai Painting but later this was used to call another tradition paining which was believed to be applied from the shape of a lotus. Considered as a Thai Tradition Painting Model which is an important base of the Thai Tradition Painting inclusive of the model and steps of drawing the painting and the application into a variety of paintings in the same structure but with different paintings such as one “Kranok”, Three “Kanok”s, Bai Thes “Kranok”s. Afterwards there was a development of the models of the painting which were different according to the ages or periods with characteristic identities with the inspiration from nature as well. Thai Traditional Ancient Showcase/Cabinet/Cupboard in the past used many divisions of Traditional Thai Crafts craftsmen to brainstorm the creation whereby each division craftsman would be with different skills and techniques of design, Thai significant divisions of craftsmen are such as wood carding, lacquer work and mother of pearl inlay.
About Product Design of Barriers Design
Authors: Wang Jia Shan , Wang Xiao
Published: September 2014

The barrier design is while manifests the design skill using the design science and art, is affecting humanity's daily life style as the modern product design's new form, Its advocate and the development will certainly to bring the positive influence to the human culture advancement. This article through to the barrier design's analysis, had the full understanding and the ponder to the barrier design, And has carried on the thorough discussion to the barrier design, pointed out that the designers should grasp person's behavior characteristic and be suitable the demand, improves person's living conditions, promotes people's life quality truly.
The Application of Green Ecological Packaging Materials in Modern Packaging Design
Authors: Gao Li Yan
Published: September 2014

With the concept of an environmental-friendly and energy saving society deepening, people are enhancing their demands of the green ecologicalization of modern packaging design. With the continuous development of products and packaging forms, packaging materials presents a development tendency of diversification. The maturity of people's concept of environmental protection promotes packaging designs transform into green ecologicalization. The green ecologicalization of packaging designs and packaging materials is undoubtedly a main direction of packaging designs in the future development. Based on this point, this article discusses about the application of green ecological packaging materials in modern packaging designs.
Ultrasonic-Assisted Extraction and Antibacterial Properties of Polyphenols of Sweet Corncob
Authors: Wang Xin , Xu Li Ping
Published: September 2014

This paper reported the extraction conditions of polyphenols compounds by ultrasonic wave and its bacteriostasis from sweet corncob. The yield of Polyphenol was selected as the index which determined by the Folin-Ciocalteu assay, single factor experiment and orthogonal experiment of ultrasound power, the extraction time, the methanol concentration (volume fraction) and solid-liquid ratio had been taken out. The result of orthogonal experiment showed that the best ultrasound power, the extraction time, the methanol concentration (volume fraction) and solid-liquid ratio were 520W, 20min, 1:10 (g/mL) and 80%, respectively. Calculation showed that the yield of Polyphenols up to 2.85%.The extract of Polyphenols from sweet corncob showed that it had bacteriostasis to EscherichiaColi,BacillusSubtilisandStaphylococcusAlbus.
Effect of Meso-Submissions to Electronic Structure and Optical Properties of Ruffled Si Porphyrins Relatives
Authors: Kang Guo Jun , Song Chao , Ren Xue Feng
Published: September 2014

A series of silicon (VI) porphyrins compounds with varying meso substitutions Si (TPP)Cl2 (where X=5,10,15,20-tetraphenylporphyrin), Si (TFP)Cl2 (X=5,10,15,20-tetrafluorenylporphyrin), Si (TQP)Cl2(X=5‚10‚15‚20-tetra (2,3,6,7-tetrahydro-1H,5H-benzo [ij] puinolizine) porphyrin),Si (TMP)Cl2(X=5,10,15,20-tetra (N,N-dimethylphenyl) porphyrin) have been investigated using density functional theory (DFT) to assess the influence of ruffled conformation on the electronic structures, frontier molecular orbital, charge carrier transport, electronic spectra. The electronic structures reveal that all these Si porphyrins display visible ruffling distortion, as the dihedral angle Cα2-N2-N4-Cα4 are ca. 30 ̊. And calculations confirm that ruffed distortion result in higher LUMO energies, lower EA values than corresponding planed Zn porphyrins, especial for similar λhole and λelectron values. These calculations suggest that the ruffled conformation bring about better charge injection and transport, which would broaden the application of distorted porphyrin in several different fields.
Reconditioning by Metal Deposition Technology - Temperature Finite Element Modeling
Authors: Nitoi Dan Florin , Dumitru Gabriel Marius , Dumitru Bogdan , Mihailescu Alexandru , Cismas Suzana Carmen
Published: September 2014

Paper presents the finite element modeling for the stress and temperature as a result of the metal deposition technology. In this case, this research method is the only one that offers information because of the working condition that are total unfavourable for stress and strain gauges. By selecting the most appropriate initial condition, the output data are very close to real result. In the paper, the temperature behavior is model because its influence in structural transformation and the stress because it can cause problems in the situation of an incorrect working technology.
Lap Joint Laser Welding of Austenitic Stainless Steel Thin Sheets
Authors: Stanciu Elena Manuela , Pascu Alexandru , Roată Ionuţ Claudiu
Published: September 2014

This paper investigates the laser welding of AISI 304 stainless steel thin sheets. For the experimental procedure a 3,3 kW Nd:Yag laser was used. Nine samples were realised during this study and the influence of the process parameters on to the geometry and microstructure of the weld bead is analysed. The best result in case of 0,5 mm stainless steel laser welding are obtained by using a density power in the range of 700-850 kW/cm2 associated with a minimum spot diameter of 0,4 mm. The weld bead compositional content was determined by an X ray dispersive field analyses. A decreasing of Mn and Si content into the weld zone was produced mainly by the burning and vaporization effects during the laser welding. Good tensile behaviour of the joints was obtained at all samples with fracture was produced at 600 MPa.
Analysis of Current State and Integrity Evaluation for the Supply Tank of Generation Unit 6 of Thermal Power Plant Nikola Tesla ”A”, Obrenovac
Authors: Arsić Miodrag , Bošnjak Srđan M. , Grabulov Vencislav , Veljović Aleksandar , Savić Zoran
Published: September 2014

Stable supply tank, with volume V = 250 m3 and operating pressure p = 1,5 MPa, of generation unit 6 at thermal power plant 'Nikola Tesla A' in Obrenovac, is designed for water-steam working fluid. It was made of steel Č 1204 as a single-part welded structure with a single wall. Cylindrical tank shell consists of 8 segments, while torispherical deep bottoms consist of 3 segments. The tank is in the horizontal position and it lays on 4 supports. There are five manometers installed at the tank for pressure control, as well as 5 spring-loaded safety valves. In this paper results of non-destructive tests performed on the tank are presented. Mechanical damages on parent material, up to 1.5 mm deep, were detected at the outer surface of the cylindrical section of the right bottom (as seen from the boiler) and on the inner surface of the shell, as well as sporadic pitting corrosion, up to 0.5 mm deep, and 2 mm misalignment of sheet metals in areas where shell segments are joined. Crack type linear indications were detected on the surface of welded joints through the use of magnetic particle testing. Through ultrasonic and radiographic testing it was determined that the homogeneity of welded joints is satisfactory. Hardness testing was performed on all segments of the tank, and obtained values were in the range between 118 and 130 HB. Metallographic examination, performed on specimens of all segments of the tank, showed that microstructure of material is either fine-grained or striped ferrite-pearlite. On the basis of test results the repair technology for shell and bottom segments was made, while on the basis of the analytical calculation of tank strength the integrity evaluation was carried out for the upcoming period of service, depending on the category of the vessel.
Cold Metal Transfer Welding of Aluminum 5456 Thin Sheets
Authors: Roată Ionuţ Claudiu , Pascu Alexandru , Stanciu Elena Manuela , Pop Mihai Alin
Published: September 2014

This study aims to determine the optimal parameters for cold metal transfer MIG welding of aluminum thin sheets. Starting from this perspective, the filler material of Al5Mg full wire type and a synergic regime of welding with a low linear energy were used. The characterization of welded joints was achieved by macro – microscopic analyses, mechanical tests (microhardness and tensile) aiming to lower the thermo - mechanically affected zone. The results highlight the major influence of the welding parameters over the weld bead geometry and tensile behaviour of the joint.
Refining the Welding Technique for Nuclear Fuel Elements at INR Pitesti
Authors: Truţă Călin , Deaconu Viorel , Gondac Cristian
Published: September 2014

Sealing of nuclear fuel material inside the fuel element clad must create a leak-tight "safety barrier" to prevent the release of radioactive products to environment. High quality welds are mandatory to withstand harsh conditions (radiation, pressure, temperature, corrosion) making possible the safe operation of nuclear reactors. The joint design, material selection and welding technique must be combined by smartly balancing possible technological options to yield the best attainable quality for the intended purpose; these choices are discussed in the paper.
For thin-walled clad to end-plug welding, heat flow pattern as determined by joint design and fitting accuracy proved to be crucial for the fusion boundary shape and moreover for the success rate in automate welding. Consequently, Finite Element Analysis of the transient thermal field during welding was performed, in order to determine the best compromise with reasonable machining precision for parts. The main features of the developed thermal model and some results illustrating its good predictions vs. actual welds are also presented.
Helium-shielded pulsed welding was initially preferred to minimize HAZ, distortion and porosity but unfortunately important cast-to-cast variation in penetration was observed with Inconel-600 plugs, due to Marangoni effect. Extensive work was done to overcome this, mainly through variation of pulsing and of the shielding gas; depth-to-width ratio can be noticeably improved with no material addition.
Out of welding classic cladding materials, studies were initiated at INR on joining oxide-dispersion strengthened (ODS) alloys and specialty austenitic formulations (e.g. 15/15Ti) since they are candidate materials of great interest for the next generation of nuclear reactors.
Influence of Slag-Flux Mixture on the Properties of Welded Joints
Authors: Dobránszky János , Németh Levente , Biczó Csaba
Published: September 2014

Submerged arc welding (SAW) is one of the most versatile welding processes. All steel grades, from non- to high alloyed, including Ni-based alloys, can be welded with a combination of various techniques. The process became common worldwide for these properties, and shows a high degree of growth in countries with significant heavy industry. In the process, a large amount of slag is formed from the flux, which is treated as waste. The slag contains non-renewable raw materials, minerals. The mining, processing represents a significant environmental impact. Short life cycle of products from high-energy input is not compatible with the eco-thinking. That is why recycling of these materials is highly appropriate from environmental and economical aspects. The paper presents a method in which the slag can be used as a valuable flux component with significant cost- and waste reduction by ensuring no loss of mechanical properties.
Determination of Some Mechanical Properties of Welded Reinforcing Steel with Self-Shielded Wires by Vibration Tests
Authors: Bereteu Liviu , Burca Mircea , Moisa Raul , Simoiu Dorin , Drăgănescu Gheorghe , Pavel Ştefănel , Nes Cristian Sorin
Published: September 2014

Reinforced concrete is a material formed by pouring concrete over reinforcement steel bars and wires and sometimes by a polymer that turns by drying in a hard and rigid composite. Welding of steel reinforcement concrete is a relatively difficult operation and with a large amount of work, given by the large number of welds that are needed and when this work is make in site conditions. The most common method of steel reinforcement welding is manual welding with coated electrode. The major disadvantage of this process is low productivity in welding effects on execution time, and the cost of welding. An alternative to manual welding with coated electrode for steel reinforcement welding on site is the welding process with self-shielded tubular wires.The aim of this paper is to determine the mechanical properties of welded reinforcing steel PC 52 with self-shielded wires, using a vibroacustic technique. To validate this method, the results obtained by vibroacoustic signal processing are compared with those determined by the tensile stresses of the same samples.
Defects Detection on the Welded Thin Steel Plates Using Vibroacustic Method
Authors: Bereteu Liviu , Vodă Mircea , Medgyesi Tiberiu , Drăgănescu Gheorghe , Simoiu Dorin
Published: September 2014

The aim of this paper is the development and validation of a vibroacustic technique to welding defects detection, especially for welded thin plate structures. In welded structures subjected to dynamic cyclic loads may appear and propagate fatigue cracks due to local structural damage. These cracks may initiate due to the technological parameters used in welding process, or due to environmental operating conditions. By the means of Finite Element Method (FEM), the natural frequencies and shape modes of welded stainless steel specimens are determined. The analysis is carried out in undamaged condition as well as damaged one, after artificially induced damages. The experimental measurement of the vibroacustic response is carried out by using a condenser microphone, which is suitable for high-fidelity acoustic measurements in the frequency range of 40 – 18.000 Hz. The vibration responses of the welded specimens, in free-free conditions, are carried out using algorithms based on Fast Fourier Transform and Prony’s series. The results are compared to modal parameters estimated using FE Analysis and with natural frequencies computed by Euler-Bernoulli theory.
Enhanced Joint Properties by Magnetic Pulse Crimping with Filler Material
Authors: Cramer Heidi , Mueller Marc , Appel Ludwig
Published: September 2014

Compared to conventional forming joining technics, e.q. mechanical crimping, the magnetic pulse crimping gives advantages because of a contact-free tooling, a symmetrical coaxial pressure and forming, as well as a low spring back after forming. Limitations of the general functionality of crimp joints also obtain for magnetic pulsed crimp joints: Leak-tightness, combined with corrosion resistance, and a partially Limitation of electrical conductivity (transition resistance). To improve and to extend the functionality of MP-crimp-joints different filler materials can be used. By environment of a public research project, adhesives, solder and metal coatings have been applied as filler materials to MP-crimping. Within the lecture the behavior of the filler materials under the influence of high speed forming, the suitable operating conditions and achieved joint properties will be described.
Weldability of Magnesium and Aluminum Alloys Using Nd-Yag Laser
Authors: Geamăn Virgil , Radomir Irinel , Pop Mihai Alin
Published: September 2014

Weldability of magnesium alloy to aluminum alloy in laser weld bonded (LWB) joints are investigated. Results showed that magnesium/aluminum could be easily joined by LWB under proper technological parameters. The weld is characterized by complex vortex flow at the bottom and there existed intermetallic compound layer between weld pool and lower sheet metal which was composed of the brittle phases of Al3Mg2. The aim of this research is to evaluate the weldability using LWD process to join Mg/Al alloys using HLD 3504 – Laser Type Trumpf, to explain the experimental conditions and interpretation of results.
Seismic Retrofitting by FRP of a School Building Damaged by Emilia-Romagna Earthquake
Authors: Formisano Antonio , Iaquinandi Antonella , Mazzolani Federico M.
Published: September 2014

A school building, located in Bomporto (Modena, Italy) and hit by the Emilia-Romagna Italian earthquake in 2012, has been investigated in the paper. The seismic vulnerabilityof the building has been evaluated by means of non-linear static analyses, which have been carriedoutthrough the 3MURI calculation program. The comparison between the damage state producedby the earthquake and the simulation results put in evidence the reliability of the numerical analysis.On the basis of the detected seismic deficiencies of the damaged building, a structuralreinforcement intervention of masonry walls has been designed by means of either FRP strips orsteel ones. Finally, a parametric analysis by varying the material and the geometrical configurationof the FRP intervention (width and spacing of the strips) has been performed with the purpose toidentify, through a cost-to-benefit comparison, the optimal retrofitting solution.
The Use of Composites in Architectural Restoration: Some Critical Considerations on the Theoretical Implications
Authors: Coisson Eva , Ottoni Federica
Published: September 2014

The use of composites in the field of architectural restoration is becoming more and more widespread, because of the great technical advantages they convey in many cases. But applying these materials to the Cultural Heritage poses not only technical issues, common to all the applications on the same materials, but also artistic, historical and, more generally, cultural ones. The present paper faces these issues, starting with some considerations on how they were dealt with in history, when the “new” materials were iron, steel and reinforced concrete. Then, the specific problems posed by the composite materials are discussed and some examples are shown in order to identify the correct approach to the many different cases that can arouse in the field of architectural restoration. There isn’t a single right solution for each problem, but there is a right approach that starts from the comprehension of the building’s behavior, passes through a comparison of all the possible solutions and aims at finding the best equilibrium among the technical and theoretical issues for the single case study.
Finite Element Modelling of Acoustic Waves Propagation in Stone Masonry
Authors: Meloni Daniel , de Nicolo Barbara , Concu Giovanna , Gillone Fabio
Published: September 2014

Abstract. The paper deals with the finite element modelling of acoustic waves propagation through a stone masonry specimen. In the last decades major efforts have been devoted to improve Sonic and Ultrasonic analysis of structural members and provide suitable correlations between acoustic wave features and the material parameters. This paper concerns the ultrasonic analysis and tomography of a masonry specimen made of trachyte blocks and cement mortar, including an inner void as an anomaly supposed to be detected by the analysis. The tests were performed with several equipments accordingly to the Direct Transmission Technique, transmitting an ultrasound signal by a piezoelectric transducer and detecting and analysing the signal received on the opposite side by another transducer. Basically the transmission time of the signal through an ideal path from the emitting and receiving transducers and the resulting wave speed are regarded as the main phenomenological measurements for non-homogeneity and anomalies detection.
Monitoring of Masonry Compression Tests in the Lab via Optical Correlation without Surface Preparation
Authors: Gabrielli Elena , Colla Camilla
Published: September 2014

Digital image correlation (DIC) is a recently developed optical technique allowing high-definition maps of displacements and deformations of the element under view. Various fields of application are already known where thermal and mechanic distorsions of the object have been explored by comparing false-colour images recorded in different deformation states. The method is becoming more common in civil engineering where first applications were limited to metal structural elements and composite material reinforcements [1-3]. The main advantages of this optical technique lie in contact-free, full-field measurements. In order to enhance the displacement spatial resolution, one of the recognised requirements of the method – in fact, so far, unavoidable – is the preparation of the investigated surface by applying a thin, white mat coating followed by a distribution of speckles (black dots) of appropriate sizes. This preliminary procedure constitutes a disadvantage of DIC due to the necessary preparation time and to inappropriateness of the requirement in case of testing high-value objects such as cultural heritage [4]. In this work, an innovative experience of DIC is presented for a case of mechanical test monitoring of brick masonry, in the lab (specimen dimensions: 0.50x0.5x0.12 m3). In addition, no coating of the surface of interest has taken place. The attempt is to validate the applicability and reliability of the method for this composite material when the masonry materials’ texture is exploited as the reference pattern to monitor geometry variations of the specimen under increased load levels. A further challenge of the experiment was due to the visible degradation state of the masonry specimen, which prior to the destructive compression load test had undergone accelerated ageing through cycles of salt crystallization and consequent discolouring and partial skin loss. The aims were to obtain from DIC high-definition full-field information able to reliably replace traditional measurement instruments such LVDTs, extensometers or TML gauges, determining instead 3D in-plane and out-of-plane displacements, tensions and strains at different load levels up to specimen collapse. The outcome of the experiment provided a better understanding of the masonry behaviour under axial load and of the local and global distribution of the above mentioned characteristic mechanical parameters together proving the reliability of the DIC technique under the specific monitoring constraints.
Diagnostics and Monitoring of the Church of San Barbaziano in Bologna
Authors: Colla Camilla , Pascale Giovanni
Published: September 2014

This paper presents a diagnostic campaign carried out in an old church located in the historic center of Bologna. The campaign's objective is to evaluate the mechanical properties, the texture, the defects, and the state of preservation of the masonry. In addition, the campaign aims to assess the state of the crack pattern and monitor its changes over time. To achieve these aims several non-destructive methods and sensors have been used for structural health monitoring.
Investigation of Damp and Salt Distribution in Outdoors Full-Scale Masonry Wall via Wireless Monitoring and Radar Testing
Authors: Gabrielli Elena , Colla Camilla
Published: September 2014

Porous construction materials such as masonry constituents are notoriously affected by weathering, pollutants attack and damp transport with manifest consequences on the masonry visible appearance and its mechanical reliability. Water transport mechanisms inside such materials as well as the chemical reactions and phase changes occurring in salt at varying combinations of temperature and humidity content have been previously studied. Nevertheless the investigation of damp and salts degradation processes since their appearance in real structural elements and the monitoring over time of their evolution is a problem never completely investigated...
Aspects of the Behavior and Analysis of Masonry Viaducts
Authors: Harvey Bill
Published: September 2014

Masonry viaducts are complex structures. They often have hidden aspects which make an important contribution to behaviour. The author is concerned to provide analytical tools for first level bridge assessment. Such tools must represent real behaviour adequately and conservatively. They must also provide the bridge owners of an indication of when and how a structure might become unserviceable. Finally, the analysis should be capable of providing guidance on strengthening where that becomes necessary.
Masonry Panels Composite Reinforcements with Epoxy Matrix, Inorganic Mortar Matrix and PS Polymer Matrix
Authors: Viskovic Alberto , Zuccarino Luigia , Kwiecień Arkadiusz , Zając Bogusław
Published: September 2014

The study mainly deals with methods of historical masonry panel's reinforcement, carried out with composite materials and with comparisons among these methods [1, 2, 3]. More in detail, in the last decade an innovative method of structural strengthening of masonry panels was proposed and tested, represented by recently developed composite structural reinforcements with polyurethane matrix [3] and here are carried out comparisons with the previous ones [1, 2].
Elastic-Brittle Fraction Model for Robust Post-Peak Analysis of Masonry Structures
Authors: Rots Jan G. , Hendriks Max A.N.
Published: September 2014

The paper presents a model that splits the material cross section into a number of parallel fractions each of them having a different elastic-perfectly brittle characteristic. The idea is that the summation of all parallel fractions provides an approximation of the overall continuum softening curve. Softening is interpreted as a gradual reduction of the cross-sectional area, which it actually is from a physical point of view. Disorder and heterogeneity are introduced by assigning the fractions i different values of Young’s modulus Ei , strength fi and area Ai such that the overall fracture energy is consumed properly. The model blends well with a scaled sequentially linear solution procedure at global level tracing structural failure via successive snapping/cracking of critical fractions. Examples are included for tension, compression, combined tension-shear and combined tension-compression. The tension-shear case shows the ability of the model to capture a gradually shifting crack orientation. Preliminary structural examples are included in this paper and further results will be presented at the conference. These relate to push-over analysis of Groningen masonry building stock subjected to man-induced earthquakes from gas depletion, a currently serious problem in The Netherlands. The results show an increased robustness and stability of the post-peak response as compared to conventional incremental-iterative procedures.
Influence of Masonry Properties on Confinement: A Mechanical Model
Authors: Lignola Gian Piero , Prota Andrea , Manfredi Gaetano
Published: September 2014

Design provisions for the repair, retrofitting, and rehabilitation of existing masonry structures are not always available and included in International and National Building Codes. Due to the extremely large variability in masonry performances, equations of general validity cannot be provided, namely relationships suitable for confinement of every masonry type, as it is done for concrete. Large amount of results obtained for concrete led to consolidated design guidelines. Despite the great research effort in the experimental field on masonry, considerable theoretical work is still needed to fully outline a definitive analytical model to predict the behavior of FRP confined masonry. In this study, a mechanically based confinement model is proposed based on mechanical parameters able to differentiate similar masonry types and to highlight that they present different confinement performance. The most relevant parameters are the compressive and tensile strength of unconfined masonry and they are discussed in the framework of solid mechanic based models based on triaxial plasticity and calibrated experimentally. The proposed approach can then be extended to other masonry types.
Influence of Salt Crystallization on Composites-to-Masonry Bond Evaluated on Site by Pull-Off Tests
Authors: Cardani Giuliana , Valluzzi Maria Rosa , Panizza Matteo , Girardello Paolo , Binda Luigia
Published: September 2014

A research, made in collaboration with Politecnico di Milano and University of Padua, has started with the aim of evaluating the influence of aggressive environmental conditions (moisture, temperature and soluble salts presence) on the bond between FRP/TRM and masonry substrates. Experimental tests were carried out on site on full-scale masonry models, built in open air in a polluted area in the hinterland of Milan, naturally subjected to thermal, R.H. and UV cycles; furthermore, they were artificially subjected to capillary rise of a solution of water and Sodium Sulphate so as to create salt crystallization cycles. On two different masonry substrates, representing a simple historic masonry structure, made either by soft-mud bricks or sandstone units with lime mortar, various FRP and TRM strips were vertically applied in order to evaluate the bond at three heights. TRM were applied with two different premixed inorganic matrices (pozzolanic lime based mortar and cement polymer modified mortar) and FRP with an organic matrix (epoxy resin). The fibres used were unidirectional carbon and glass fabrics for FRP, and a bidirectional carbon net for TRM. The bond was evaluated by means of pull-off tests and the first results, herein presented, show the influence of moisture presence and of salt crystallization cycles on the different used matrices.
Conservation of the Structure and Materials of Historic Masonry Walls
Authors: Jasienko Jerzy , Bednarz Łukasz , Bajno Dariusz
Published: September 2014

The paper presents a structural analysis, restoration programme and scope of conservation work essential for protecting historical values based on the example of an overstretched retaining wall providing support for the embankment of an heritage church. The focus was on analysing the status of an historic stone wall constructed in part with bog iron ore (metal ore or iron-rich sedimentary rock). Ore was used for iron smelting and also as a building material. Bog iron ore was frequently used in construction across Poland, especially in places where the raw material was locally available, aesthetically attractive and had mechanical properties approximating the durability of ceramic bricks. The material was characterised by high porosity, low resistance to diffusion and high resistance to freezing, which meant that it could be used successfully in structures subjected to atmospheric impacts without additional protection
Diagonal Tensile Strength of AAC Blocks Masonry with Thin Joints Superficially Strengthened by Reinforced Using GFRP Net Plastering
Authors: Kałuża Marta , Galman Iwona , Kubica Jan , Agneloni Chiara
Published: September 2014

In recent years, the autoclaved aerated concrete has become as one of the most popular material used in erecting of small housings as well as multi-apartment residential buildings. Recommended construction technology involves the use of the ACC blocks arranged on thin bed joints, with the head joints left unfilled. Practice has shown that this type of construction is characterised by low crack resistance, which was also confirmed during experimental investigation [1]. One of the solutions to this problem, proposed by the staff of the Silesian University of Technology, was the superficial strengthening of such type of masonry walls. Strengthening materials tested so far (glass and carbon fibre mesh used in FRP system solutions) gave very promising results but a relatively high cost of the material itself constituted the main drawback. This prompted a further search for new and relatively inexpensive materials that would allow improving the use of the existing structures made of AAC blocks.
The goal of the laboratory test results presented in this paper was to determine the influence of wall surface strengthening made of not expensive GRFP mesh (dedicated as reinforcement of thin external plastering in thermal insulation systems) on the behaviour and mechanical properties of masonry wallettes made of AAC blocks with thin joints. Three series of masonry specimens were tested: not strengthened wallettes (as reference members), walls with superficial strengthening only on one side and walls with both sides strengthened. A total of 18 specimens subjected to diagonally compressive loading were tested (6 in each series). The results turned out to be highly promising. Increasing of shear capacity of both types of superficially strengthened masonry in comparison with reference members was observed. The tests also allowed determining a positive effect of external reinforcement on the type of cracking and failure mode of such walls.
Strengthening of Thin Masonry Arches
Authors: Borri Antonio , Castori Giulio , Corradi Marco
Published: September 2014

The innovative technique here illustrated is the result of historical evolution of an ancient system of reinforcing tiled vaults belonging to the constructive Spanish tradition. Such a traditional technique consists in the lamination of flat rectangular tiles or thin bricks into thin vaults known as boveda tabicada. Since the use of modern technologies may improve the mechanical performance of the traditional materials, the core of the proposed strengthening system is based on the idea of combining the peculiar features of tabicada technique with the good tensile properties of composite materials. More in detail, it is possible to obtain reinforced masonry vaults or arches by overlapping different layers of tiles or thin bricks and laminates, embedded within an hydraulic mortar, so that the entire assembly may act as a single structural unit. Eighteen prototypes of tiled arches were tested under a monotonic vertical load applied at the keystone. The influence of the types of reinforcement, number of layers and properties of hydraulic mortar has been investigated. Laboratory outcomes are presented and discussed in the paper considering mechanical behavior of specimens and axial stress-axial strain relationships.
Application of Acoustic Emission Technique for Bond Characterization in FRP-Masonry Systems
Authors: Ghiassi Bahman , Verstrynge Els , Lourenço Paulo B. , Oliveira Daniel V.
Published: September 2014

The acoustic emission (AE) technique is used for investigating the interfacial fracture and damage propagation in GFRP-and SRG-strengthened bricks during debonding tests. The bond behavior is investigated through single-lap shear bond tests and the fracture progress during the tests is recorded by means of AE sensors. The fracture progress and active debonding mechanisms are characterized in both specimen types with the aim of AE outputs. Moreover, a clear distinction between the AE outputs of specimens with different failure modes, in both SRG-and GFRP-strengthened specimens, is found which allows characterizing the debonding failure mode based on acoustic emission data.
Analytical Modeling of Composite-to-Masonry Prisms Bond
Authors: Malena Marialaura , de Felice Gianmarco
Published: September 2014

The composite-to-substrate interfacial stresses transfer mechanism is one of the critical issues in externally-bonded structural strengthening by means of composite fabrics. In this work, an analytical approach for modeling the debonding process of a composite on a non-homogeneous substrate is developed and applied to simulate the loss of bond of FRP on brick masonry. The analytical formulation is based on the experimental outcomes of bond shear tests, which are part of a Round Robin activity involving several laboratories. The experimental work is the follow up of a previous one [1], and comprises 12 single-lap shear tests of four kinds of unidirectional reinforcement, i.e., glass, carbon, basalt and steel, applied with epoxy resin to masonry prisms composed by five clay bricks and four mortar joints. The analytical simulations of the experimental tests rely upon a bi-linear non-homogeneous bond-slip law that was calibrated using the experimental population. Eventually, the analytical results are compared to experimental ones both, in terms of global (load to displacement curve) and local behavior (strain profile on the reinforcement for increasing load values).
ZnAl1.9Eu0.1O4 Nanoparticles Functionalized with Methylmethacrylate and Ethylenediamine Monomer Mixtures
Authors: Santos P.T.A. , Santos Polyana T.A. , Araújo P.M.A.G. , Costa A.C.F.M.
Published: September 2014

This work aim to functionalize the ZnAl1.9Eu0.1O4spinel with ethylenediamine and methylmethacrylate monomer mixtures. ZnAl1.9Eu0.1O4nanoparticles were obtained according to the theory of propellants and explosives by combustion reaction. The samples were added to the silane agent 3-aminopropyltriethoxysilane. After silanized were functionalized with a monomers mixture. By X-ray diffractogram, it was observed the formation of a major phase of ZnAl2O4cubic normal spinel and the secondary phase EuAlO3. The FTIR spectra for ZnAl1.9Eu0.1O4exhibit absorption bands below 1000 cm-1, and after the functionalization showed two conjugate bands that were attributed to the presence of free NH2groups and the binding of oxygen to the group NH2, and strips Si-O, originating from the silane agent. The emission spectra for samples before and after functionalization showed spectral lines5D0→7F0,7F1→5D0,5D0→7F2,7F3→5D0and5D0→7F4and luminescence quantum yield of 58%, but the sample functionalized with a mixture monomers showed an increase in intensity on transition5D0→7F2and quantum yield of 67%.
Direct Manufacture of Hydroxyapatite Scaffolds Using Blue Laser
Authors: de Meira Camila Roberta , Gomes Dannylo Thadeu , Correa Braga Francisco José , Purquerio Benedito de Moraes , Fortulan Carlos Alberto
Published: September 2014

The study deals with the direct manufacturing of hydroxyapatite scaffolds using selective polymerization of the slurry liquid phase. The bovine hydroxyapatite has great similarity with the human bone structure, making it able for a direct connection with the bone tissues. This study aims to obtain scaffolds using a new technique of rapid prototyping, obtained by polymerization of acrylic resin (liquid phase of slurry) by ultraviolet light present in a range of the band spectrum emitted by the blue laser light. Sub-micrometer hydroxyapatite was obtained by the calcination and grinding of bovine bone in a vibratory mill. Mixtures of hydroxyapatite and resin were prototyped in three-dimensional pieces and sintered afterword and subjected to blue laser emission path directed in a CNC equipment. Grounded particles obtained in the grinding vibratory mill, with equivalent diameter of 0.35 microns, were reactive enough to compensate the low green densification bellow 50 vol%. Polymerization tests realized indicated that the incidence of the laser with fluency of 170 mW.s/mm2promoted the curing of the 0.5 mm diameter pieces in depth about 0.5 mm, which allowed the prototyping of the scaffolds with sufficient mechanical strength for handling.
Anodic Protection of Carbon Steel AISI 1006 Using the Binder of Undoped Polyaniline
Authors: Sanchotene Silva Rodrigo , Ferreira Carlos Arthur , Zoppas Ferreira Jane , Meneguzzi Álvaro
Published: September 2014

The use of intrinsically conductive polymers such as polyaniline (PAni) has been presented as an alternative protective coating against corrosion, it intensifies the effect of anodic passivation and protection of the material. Given the difficulty in obtaining films of polyaniline in the oxidized form and driver in a self-supported and cohesive on the surface of metal substrates. Was held the undoped of the polymer, with the use of NH4OH solution to passing the PAni oxidized state and non-conducting polyaniline emeraldine base known as PAni EB. The complete mixture of PAni EB, organic solvent and plasticizer 4-chloro-3-methylphenol, allowed to obtain a resin. This was applied in AISI 1006 steel plates with the aid equipment Spin Coater. The film was characterized by thermal analysis TGA, where it was found that the coating is the result of the reaction components, predominantly the structure of PAni EB. The electrochemical tests of Cyclic Voltammetry and Potential Open Circuit were carried out in 2 molL-1H2SO4solution, which indicated the formation of redox couple polymer-metal, which provides the formation of passivating oxides, which allow the metal anodic protection against corrosion.
Evaluation of the Current Modulation Effect on the Cathodic Efficacy during Copper Electroplating in Alkaline Medium
Authors: da Cunha Maico Taras , Pinto Rodrigues Paulo Rogério
Published: September 2014

The main aim of this paper is to study copper ions electroplating, evaluating the cathodic current efficacy, from cyanide ion free alkaline baths, stabilized by different complexant agents for the Cu2+ions. The cathodic current efficacy was assessed through quartz microbalance measurements, employing different current modulations. Results revealed that the pulsed current application has great influence on the cathodic current efficacy during electroplating in the baths under study.
Production and Characterization of Copper-Niobium Composite Electrocoatings
Authors: Robin Alain , Rosa Jorge Luiz , Borges Silva Messias
Published: September 2014

Copper-niobium composite electrocoatings were obtained by co-electrodeposition in acidic copper sulfate bath containing suspended niobium particles. The amount of incorporated particles was evaluated using a Central Composite Design (CCD) with three factors of control (cathodic current density, stirring rate and particle concentration in the bath) at three levels each. A great influence of particle concentration was observed. The stirring rate also had influence but to a lower extent and the cathodic current density was the least significant factor. The combination, both cathodic current density and particle concentration at the highest levels and stirring rate at the lowest level, led to the highest amount of incorporated particles. The behavior was not linear between the high and low levels for all factors. The roughness of the composites was higher than the pure copper coatings and increased with increasing current density. The microhardness of the composite layers was higher than that of pure copper deposits obtained under the same conditions due to copper matrix grain refinement and increased with the increase of both current density and incorporated particle volume fraction.