bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimization of Horizontal Plate Fin Heat Sink in Natural Convection for Electronics Cooling by Simulated Annealing Algorithm
Authors: Zhou Li , Liu Yang
Published: August 2014

In this study, the simulated annealing (SA) algorithm was adopted to optimize the geometry of horizontal plate fin heat sink by the extreme entransy dissipation principle. The alculation of the entransy dissipation rate was presented in detail. Using the entransy dissipation rate as the objective condition, the geometry optimization of the fin heat sink was conducted. To verify the results, the heat source temperature and the entropy generation rate were also calculated in the procedure. It is found that the entrasy dissipation rate, entropy generation and heat source temperature have the similar trend. The extreme entransy dissipation principle and minimization of entropy generation play similar roles in the geometry optimization of plate fin heat sink.
Reliability Analysis and Countermeasures on Type Selection of Boiler Induced Draft Fans
Authors: Xu Ming Feng , Zhang Ying Shuai , Wang He Cen , Wang Lei , Ren Li Ming
Published: August 2014

For the retrofit of precipitation and flue gas desulfurization (FGD) system, stalling issue of the boiler axial-flow induced draft fan (IDF) was analyzed. By testing the running characteristic parameter of IDF at the scene, and combining with its characteristic: curve, it was discovered that the actual working point of IDF nears its theory stall line, and stalling issue would appear during running. In order to make the actual working point of IDF keeping away from its theory stall line and avoid the stalling issue of IDF, KSE ( the steady implement of function ) equipment was installed at the entrance of the IDF' to changing the position of IDF theory stall line. The stalling issue of IDF was analyzed and probed, and the problem that the stall margin selection should be considered carefully in IDF retrofit and type selection was presented, which gives some useful suggestion for the similar retrofit in power plant.
Treatment and Analysis on Unit Trip Caused by Primary Fan Stall
Authors: Liu Jing Yu , Wang Shui Long , Xu Ming Feng , An Jing Xue , Ju Hai Xia
Published: August 2014

As a result of incorrect operation causing the stall of primary fan, the pressure of primary air continuously decreased. Therefore, the combustion stability in boiler has been disturbanced greatly, and the generation unit trips due to water-coal ratio imbalance. In this paper, the stall accident resulted from incorrect operation have been analyzed, and correct operation for the fan have been put forward. Namely, the precursory phenomena of stall can be found and eliminated. Correct operations can keep the pressure of primary air stable. It is concluded that adopting the suitable water-coal ratio and air-coal ratio are helpful to keep the unit on safe.
Fabrication of V-Groove High Temperature Oxygen Sensor by Gallium Oxide
Authors: Yarn Kao Feng , Luo Win Jet
Published: August 2014

Effects of a metal oxide structure on the oxygen sensing properties are investigated. In the existence of the etched V-groove gallium oxide geometry, its electrical and sensing properties, i.e., high sensitivity and response time areinvestigated. Grain sizes of the material are dependent on different sputtering conditions and investigated by AFM. Under the partial-voltage circuit measurement, it can be confirmed that the increase of temperature will result in the increase of resistance for the Ga2O3 oxygen sensor. From experiment, good stability and repeatability of the oxide sensor are demonstrated when tested under oxygen concentration. These properties show that the oxide structure has a good potential for high sensitivity oxygen sensor.
The Research of Time Delivering Technology in SDH Network
Authors: Yao Ying
Published: August 2014

This paper proposed a precept on time deliver with consideration of the characteristic of SDH fiber-optic network. The computational model and Network configuration of the precepts was given in this paper. The method can be used to time deliver for SDH fiber optic network. And a calibration method is proposed in this paper that Single-ended one-way frequency calibration. The time precision of delivering can be improved by Single-ended one-way frequency calibration.
Research on Energy Saving with Automatic Detection Method of Building Thermal Indices
Authors: Han Ling Yan , Zhao Yan Ling , Zheng Xiao Shi , Cheng Guang He , Liu Gung Qi
Published: August 2014

This paper describes a method of how to test a building’s thermal defect automatically and completely. Though this method is not perfect in all parts, it does provide a innovative solution for the problem of building detection.
An H-Phosphonate Approach for the Preparation of Purine-Nucleoside Monophosphates
Authors: Wang Cheng Jun , Gong Shan Shan , Sun Qi
Published: August 2014

Two purine-nucleoside monophosphates have been prepared from the corresponding nucleoside 5′-H-phosphonate precursors via sequential silylation, oxidation, and hydrolysis reactions in a one-pot manner. Compared to the reaction performed in the presence of pyridine, the hydrolysis of iodophosphate in the absence of pyridine generated nucleoside 5′-monophosphates as the major product. The experimental results indicated that the reaction between the formed nucleoside 5′-monophosphate with the residual iodophosphate intermediate was relatively slow, making the self-condensed dinucleoside diphosphate a minor product in this reaction.
Preparation of Modified 1,6-Hexanediamines
Authors: Li Xiao Chuan , Gong Shan Shan , Sun Qi
Published: August 2014

A series of novel 1,6-diaminohexanes functionalized with phosphonates have been synthesized under solvent-free conditions and characterized by NMR and MS. The experimental results indicated that excess aldehyde and phosphite and elevated temperature were required for effective formation of the bis-funcationalized alkyl diamines.
Sustained Release Properties of Aminophylline Sustained Release Tablets Based on Exfoliated Graphite
Authors: Gao Lin , Wei Ye
Published: August 2014

This study attempted to develop sustained release tablets based on exfoliated graphite. The in vitro evaluation of the prepared tablets was carried out to study its sustained release properties by means of UV/VIS spectroscopy. The results show that the release rate of aminophylline decreases with the increase of the content of graphite for the aminophylline sustained release tablets based on exfoliated graphite. The graphite in the aminophylline sustained release tablets will delay the release of aminophylline when the exfoliated graphite content in the sustained release tablets is less than 25%, the graphite will prevent the release of a part of the aminophylline when the exfoliated graphite content exceeds 40%. The reproducibility of the prepared aminophylline sustained release tablets is acceptable.
Wear Resistant Surface Composite Produced by Ultrasonic-Assisted Argon-Arc Clad Injecting Ti(C, N)
Authors: Zhang Ning , Wang Shu Chen , Jiang Xu , Qu Shen Liang , Chen Hao
Published: August 2014

This experiment was on the basis of the argon-arc clad injection technology, Ni60 self-fluxed alloy powder was coated on the surface of Q235 steel plate, then TiC, TiN, MoC and Co powder were sprayed by the modificated injection device, and at the same time the powder was vibrated by the ultrasonic-assisted vibration device self-designed. So the sprayed powder particles were smaller, shape was more regular, and distribution more uniform. The results show that the microhardness of composite coating was more than 5 times than that of the matrix, and the wear volume was about 1/5 than the matrix. The good combination, high strength and high wear resistance composite coating was obtained.
Practical Synthesis of 5-Hydroxymethyl-2′-Deoxycytidine
Authors: Sun Jian , Gong Shan Shan , Sun Qi
Published: August 2014

A practical method for the synthesis of 5-hydroxymethyl-2′-deoxycytidine via dithio-deoxyuridine intermediate has been developed.
S-Parameters of Bismuth Iron Garnet (BIG) Filled Polyvinylidene Fluoride Composite Using Rectangular Waveguide Method
Authors: Soleimani Hassan , Yahya Noorhana , Shameli Kamyar , Abbas Zulkifly , Chuan Lee Kean , Amighian Jamshed
Published: August 2014

Nanosized Bismuth Iron Garnet (BIG) was synthesized via sol-gel method. The nanomaterials with ferrite structure were heat-treated at different temperatures from 700 to 1100 °C. The structure and morphology were characterized by Powder X-ray diffraction (PXRD) and Scanning electron microscope (SEM), respectively. The PXRD show that with the increase of temperature the size of crystallites for BIG gradually increased. The BIG ferrite nanopowder was composited with polyvinylidene fluoride (PVDF) by solution casting method with different ferrite ratios. The magnitudes of S-parameters of PVDF/BIG were investigated using rectangular waveguide in conjunction with a microwave vector network analyzer (VNA) at microwave frequencies. The S-parameters of PVDF/BIG are found to be slightly different from those of ferrite contents in polymer composites. The S11 is found to be increased by increasing the ferrite content of the composites as well as with frequency while the S21 is observed to decrease with increase in ferrite content.
Optimisation of Pulsed Nd: YAG Laser Processing of Gray Cast Iron for Enhanced Surface Properties
Authors: Fauzun Fazliana , Aqida Syarifah Nur , Wahab Md. Saidin , Saidin Wahab
Published: August 2014

This paper presents laser surface modification of gray cast iron for enhanced surface hardness properties. A 300 W high power Nd:YAG laser system with pulse mode was used to modify gray cast iron samples surface. Laser processing was conducted using a 33 full factorial design. Three controlled parameters were laser power, pulse duration and overlap percentage. The modified surface was characterised for metallographic study, roughness and hardness. Metallographic study and surface morphology were conducted using optical microscope while hardness properties were measured using Vickers scale. Surface roughness was measured using a 2D stylus profilometer. The results show that hardness of laser modified surface increased due to grain refinement. The overlapping rates increased significantly with decreasing laser scanning speed which affected sample surface integrity. Low surface roughness obtained at the highest scanning speed of 1400 mm/min, and low power of 830 W with pulse repetition frequency of 50 Hz. Process optimization was carried out for maximum surface hardness and laser modified depth, and minimum surface roughness. These findings indicate potential application of cast iron for high wear resistant applications through laser surface modification.
Friction Stir Processed of 6061-T6 Aluminum Alloy Reinforced with Silica from Rice Husk Ash
Authors: Hussain Zuhailawati , Halmy Mohd Noor , Almanar Indra Putra , Dhindaw Brij Kumar
Published: August 2014

This paper presents a development of a composite using friction stir process of AA606-T6 aluminum alloy reinforced with amorphous silica obtained from rice husk ash. The amorphous silica was produced after acid leaching and calcinations at 500°C. The silica powder was placed into a groove made in the joining line of AA606-T6 plates prior to friction stir process. Hard silica particles restricted the grain growth of aluminum matrix that contributed to a slight increase in hardness. Hardness decreases in zones under the tool was observed because AA6061-T6 alloy was sensitive to friction heat generated by the tool. Ageing at 200°C increased the hardness of the aluminum in the friction stir process zones.
Improving the Production of Self-Assembled ZnS:Mn Nanocrystals through the Modification of Sol Gel – Spin Coating Approaches
Authors: Noor Azie Azura Mohd Arif , Shaari Sahbudin , Mohammad Syuhaimi Abd Rahman
Published: August 2014

It is difficult to produce a good film consisted of nanocrystals with good alignment. So far, a lot of methods and especially expensive vacuum-based methods have been used to produce such films. In this paper, sol gel and spin coating method were introduced. The combination of these simple and cheaper methods was used because of the high potential of those methods to produce good quality nanocrystals. First, nanocrystals were produced by sol gel method and later spin coating was done to control the thickness of the nanocrystals film. During the spin coating process, a metal tape was used to avoid solution from splashing out from the glass substrate. Subsequently, nanocrystals film was heated up from room temperature to 400 °C. To study the alignment of nanocrystals, Field Emission Scanning Electron Microscopy (FE-SEM) was used. Through this analysis, we found that the nanocrystals was in spherical pattern and the alignment of this film was well arrayed. Here, the combination of the two cheaper and simpler methods can be used to produce good quality of nanocrystals thin film and at the same time can save our research cost.
Effect of Sintering Duration on Pure PZT for Piezofan Application
Authors: Bahanurdin Fatin Khairah , Sharif Shafiza Afzan , Ahmad Zainal Arifin , Mohamed Julie Juliewatty
Published: August 2014

Recently, pure PZT have been used as a piezofan in electronic application. Properties that piezoelectric fan should have are high mechanical piezoelectric coupling factor, high dielectric constant, easily polarized and high piezoelectric charge constant. Soft PZT is a suitable candidate to fulfill this requirement. The samples will be prepared via high planetary mill; due to this process can skip calcinations process, which can reduce a lot of cost. This process also can avoid PbO loss during sintering process. The microstructure and electrical properties of PZTceramic were found to be more sensitive to the sintering condition. Preliminary works have been done in order to find a suitable sintering duration in order to produce a good PZT formation. SEM analysis indicated that shorter sintering time promotes fine structure and densification. This have been proves where relative density of the obtained sintered PZT ceramics was measured to be approximately 99 % of the theoretical density.
Development of Silver-Coated Gold Nanoparticles and its Conjugation for Labeling on Lateral Flow Immunoassay
Authors: Makhsin Siti Rabizah , Razak Khairunisak Abdul , Noordin Rahmah
Published: August 2014

This work describes the formation of silver-coated gold nanoparticles (Ag-AuNPs) using the seeding-growth method. 15 nm AuNPs seeds were synthesized using the citrate reduction method. In the growth stage, the adding sequence of seeds, ascorbic acid (AA), gold chloride (HAuCl4) and silver nitrate (AgNO3) was explored. The effect AgNO3 volume (20 mM) was varied at 0.10, 0.25, 0.50, 1.00, 1.25 and 1.50 ml. Morphology of Ag-AuNPs was observed using a Transmission Electron Microscope (TEM) while UV-Vis Spectrophotometer was used to study the concentration and absorption spectra of colloidal Ag-AuNPs. Zeta-sizer analysis was used to study the particle size distribution of Ag-AuNPs in colloidal form. In the growth stage, the optimum adding sequence was found by adding AA as a reducing agent into AuNPs seeds followed by the addition of HAuCl4 and AgNO3. This reshuffle sequence is chosen due to the presence of two absorbance peaks at 398 nm and 501 nm compared to others. From TEM images, increasing concentration of silver ions affected the optical properties, end size of Ag-AuNPs as well as raises the concentration of the colloids suspension. The biological properties of samples Ag-AuNPs (0.1 ml to 0.5 ml AgNO3) were studied by performing the conjugation process between samples and antibody; goat anti-human IgA (GaHIgA). An additional washing process was required to perform conjugation for Ag-AuNPs in order to remove by-product or unreacted chemical produced during synthesis process. The Ag-AuNPs was successfully conjugated with GaHIgA and required a minimum concentration of antibody (9µg/ml) after washing process. In addition, the washed Ag-AuNPs also improved its binding capability with GaHIgA by giving higher intense signal when tested with lined Human IgA on the lateral flow immunoassay (LFI) compared to un-washed Ag-AuNPs.
The Effect of Oxygen Precursor Concentration to the Iron Oxide Nanoparticles Properties for Lateral Flow Immunoassay Application
Authors: Noorhashimah Mohamad Nor , Razak Khairunisak Abdul , Noordin Rahmah
Published: August 2014

In this study, the influence of hydrogen peroxide (H2O2) concentration to the iron oxide nanoparticles (IONPs) properties prepared using the precipitation method was investigated. The H2O2 concentration was varied from 0.85 M to 5.1 M. The concentration of H2O2 influenced the crystallinity and the growth rate of the IONPs precipitates. Increasing the concentration of H2O2 increased the crystallinity and expedited the growth rate of IONPs. The optimum concentration of H2O2 was 1.7 M. From the transmission electron microscopy (TEM) images, the size of IONPs obtained was ~14 nm and the X-ray diffraction (XRD) spectra showed the presence of spinel cubic lattice of maghemite (γ-Fe2O3). The magnetic measurement of IONPs using vibrating sample magnetometer (VSM) was showed that the IONPs exhibited superparamagnetic properties. Furthermore, the electrostatic repulsion using percloric acid (HClO4) and steric stabilization using silane polyethelene glycol (SiPEG) were created surround IONPs in order to obtain a stable colloidal IONPs for the conjugation process. The stable IONPs were then conjugated to the antibody and tested in the lateral flow immunoassay as the labelling agent.
Design and Synthesis Silica-Polyelectrolyte-Iron Oxide Nanocomposite with Magnetic-Catalytic Bifunctionalities for Dye Removal
Authors: Che Hui Xin , Yeap Swee Pin , Latif Ahmad Abdul , Lim Jit Kang
Published: August 2014

Incorporation of iron oxide nanoparticles into Poly(diallydimethylammonium chloride) coated silica colloids is developed to produce novel nanocomposite. The structure is synthesized via layer-by-layer assembly with the entire process driven by electrostatic interaction. Dynamic light scattering and zeta potential measurements are employed to monitor the evolution of the nanocomposite from its constituent materials to full development of final structure. Morphology of the as-synthesized nanocomposite is observed by transmission electron microscopy. The magnetic responsiveness under low magnetic field gradient enables the aforementioned nanocomposite to be recovered for recycle purpose. The engineering application of this material is tested by taking Methylene Blue and Remazol Brilliant Blue R dyes as model system. The study reveals the efficiency and activity of the nanocomposite for dye removal during four consecutive runs.
Low Young's Modulus β-Ti Alloys for Biomedical Applications
Authors: Mohamed Abdel Hady Gepreel , Mervat Ibrahim , Kobayashi Sengo
Published: August 2014

The low Young's modulus of Ti-alloys is of particular importance for biomedical applications to prevent or reduce the occurrence of stress shielding. This paper shows some ways that are used to produce new Ti-alloys with low Young's modulus for biomedical applications. The different factors that affect the Young's modulus such as the phase's stability, role of alloying elements, plastic deformation, and texturing are discussed. The low-cost and low-Young's modulus Ti-alloys (i.e., alloys composed mainly of the common elements and/or contains a minimum amount of the high-cost rare elements) are also discussed.
Compact and Energy-Efficient Field Emission Cathodes for Sensor Applications
Authors: Schreiner Rupert , Langer Christoph , Prommesberger Christian , Dams Florian
Published: August 2014

We report on miniaturized silicon field emitter arrays for the application in compact and energy-saving vacuum-microelectronic devices, e.g. sensors or x-ray tubes. Since standard silicon semiconductor technology has been used for the fabrication, they may be easily integrated with other silicon based circuits and devices on the same chip. The silicon tip geometry and the operating conditions were optimized in order to obtain highly uniform and stable electron field emission from large area cathode arrays. A series of uniform hexagonal tip arrays containing each 547 tips were fabricated and characterized. The electron emission properties of both individual tips as well as of complete emitter arrays were investigated. A saturation level in the voltage-current characteristics was found, which can be explained by the limitation of the supply of electrons due to the p-type silicon wafer material. When operating the arrays in the current saturation regime at an emission current of ~ 1 nA per tip, a highly stable and low noise emission can be observed.
Effect of Thickness of Porphyrin on Electrical Properties of Organic Devices
Authors: Tan Pi Lin , Yeap Guan Yeow , Chow Wen Shyang , Schreiner Rupert , Cheong Kuan Yew
Published: August 2014

The study on electrical properties for both 2,3,7,8,12,13,17,18-octaethyl-21,23H-porphine Cu (II) (Cu-porphyrin) and 2,3,7,8,12,13,17,18-octaethyl-21,23H-porphine (porphyrin) thin film, which were fabricated using spin coating method was conducted. Porphyrins were diluted with chloroform of various concentrations (0.05 mg/ml, 0.1 mg/ml, 0.5 mg/ml, 2.0 mg/ml and 3.0 mg/ml). The solution was spin coated on top of glass substrates. A layer of aluminum was evaporated on top of the organic thin film through thermal evaporation and shadow mask was placed on top of the organic thin film where two electrodes with a gap of 50 μm were formed. Surface morphology of the organic thin film was observed by scanning electron microscope (SEM) and profilometer. Different concentrations of organic solutions greatly affected the molecular packing and arrangement order of the organic thin film and thickness of the organic layer and eventually affected electrical properties of the devices.
Microwave Synthesis of ZnO Nanoparticles for Enhanced Oil Recovery
Authors: Alnarabiji Mohamad Sahban , Yahya Noorhana , Bee Abd Hamid Sharifa , Azizli Khairun Azizi , Shafie Afza , Solemani Hassan
Published: August 2014

Synthesising zinc oxide nanoparticles to get certain specific characteristics to be applied in Enhanced oil recovery (EOR) is still challenging to date. In this work, zinc oxide (ZnO) nanoparticles were synthesised using the sol-gel method by dissolving zinc nitrate hexahydrate in nitric acid. The ZnO crystal and particles morphology and structure were determined using X-ray Diffractometer (XRD) and Field Emission Scanning Electron Microscope (FESEM). In this study, a microwave oven was used for annealing ZnO without insulating a sample in any casket. The results show that 30 and 40 minutes of annealing and stirring for 1 hour influenced the morphology and size of zinc oxide particles in nanoscale. These parameters could be tailored to generate a range of nanoparticle morphology (agglomerated nanoparticles in a corn-like morphology), a crystal size with the mean size of 70.5 and 74.9 nm and a main growth at the peak [10. EOR experiment were conducted by dispersing 0.10 wt% ZnO NPs in distilled water to form a ZnO nanofluid. Then the fluid was injected into the medium in the 3rd stage of the oil recovery to present EOR stage. It was found that ZnO nanofluid has the ability to extract 8% of the original oil in place (OOIP).
Freeze-Thawed Hybridized Preparation with Biomimetic Self-Assembly for a Polyvinyl Alcohol/Collagen Hydrogel Created for Meniscus Tissue Engineering
Authors: Puttawibul Puttiporn , Benjakul Soottawat , Meesane Jirut
Published: August 2014

Freeze-thawed hybridized preparation and the biomimetic self-assembly technique were used to fabricate hydrogel as tissue engineered scaffolds for meniscus tissue. Because of the advantages of both techniques, they were hybridized together as an interesting preparation for hydrogel. Three molecular weights (high, medium, and low) of PVA were prepared in a biomimetic solution before formation into hydrogel by freeze-thawing. The most suitable molecular weight PVA for hydrogel formation was chosen to be mixed with collagen. PVA, PVA/collagen, and collagen were prepared in biomimetic solutions and freeze-thawed into hydrogels. The hydrogels were analyzed and characterized by FTIR, DSC, and SEM. FTIR characterization indicated that high molecular weight PVA formed molecular interaction better than the other molecular weights, and PVA molecules formed molecular interaction with collagen molecules via –OH and C=O groups. DSC characterization showed that the hybridized preparation of freeze-thawing and biomimetic self-assembly kept the characteristics of PVA and collagen. SEM analysis demonstrated that the morphological formation of PVA/collagen was hybridized during freeze-thawing and collagen self-assembly. The morphological structure was organized into a porous network structure. The porous structure showed a rough wall that was formed by the hybridized structure of the crystal domain dispersed in amorphous and collagen self-assembly.
The pH-Dependent Properties of the Biphasic Calcium Phosphate for Bone Cements
Authors: Srakaew Nuan La Ong , Rattanachan Sirirat Tubsungnoen
Published: August 2014

Self-setting calcium phosphate cement (CPC) has been used in bone repair and substitution due to their excellent biocompatibility, bioactive as well as simplicity of preparation and use. The inherent brittleness and slow degradation are the major disadvantages for the use of calcium phosphate cements. To improve the degradation for the traditional CPC, the apatite cement formula incorporated with β-tricalcium phosphate (β-TCP) with varying concentration were studied and the effect of the pH value of liquid phase on the properties of this new calcium phosphate cement formula was evaluated. The apatite cements containing β-TCP for 10 and 40 wt.% were mixed into the aqueous solution with different pH values and then aging in absolute humidity at 37°C for 7 days. The setting time and phase analysis of the biphasic calcium phosphate were determined as compared to the apatite cement. For proper medical application, the compressive strength, the phase analysis and the degradation of the CPC samples at pH 7.0 and 7.4 were evaluated after soaking in the simulated body fluid (SBF) at 37°C for 7 days. The results indicated that the properties of the samples such as the setting time, the compressive strength related to the phase analysis of the set cements. The high degradation of the CPC was found in the cement with increasing β-TCP addition due to the phase after setting. Apatite formation with oriented plate-like morphology was also found to be denser on the surface of the biphasic bone cements after soaking in SBF for 7 days. The obtained results indicated that the cement containing β-TCP mixed with the liquid phase at pH 7.4 could be considered as a highly biodegradable and bioactive bone cement, as compared to the traditional CPC.
Distributed Structural Monitoring for a Smart City in a Seismic Area
Authors: Gattulli Vincenzo , Potenza Francesco , Graziosi Fabio , Federici Fabio , Colarieti Andrea , Faccio Marco
Published: August 2014

The concept of Smart City (SC) has been introduced to categorize the vast area of activities to enhance the life quality of citizen, which are characterised by a pervasive use of Information and Communication Technologies (ICT), to help cities, with various urban domains, making better use of their resources. Monitoring the structural behaviour of strategic buildings and monuments may be desirable for citizens, which have recently experienced a destructive earthquake in their own town, such as the case of L’Aquila. The paper deals with the design of a distributed structural monitoring network for a selected set of strategic structures belonging to the city of L’Aquila. Preliminary design criteria are discussed on the basis of previous authors’ experiences in this context. Specific attention has been dedicated to analyse the expected acceleration response measurements induced by small seismic excitations for the general purpose of monitoring.
Identification of the Modal Properties of a Building of the Greek Heritage
Authors: Diaferio Mariella , Foti Dora , Giannoccaro N.I.
Published: August 2014

In this paper, the experimental modal identification analysis of the public building “San Giacomo” in Corfu (Greece) is illustrated. It represents the unique example of a structure built utilising carves stones inside the city of Corfu. The building has a rectangular plan shape with dimensions 24.75 x 14 m, and height 9 m; all the floors are made by wood. The monitoring system consists of several elements properly connected: the units of acquisitions or piezoelectric accelerometers (in total 18 installed on the different walls) with a sensitivity of 1000 mV/g; the data acquisition system or DAQs positioned at each monitored level; the laptop with an acquisition software; the cables that connect all elements to each other.
The paper describes the phases of the investigations, the technical details of the performed in-situ tests, the first identified frequencies of the building by means of the classical methods of Operational Modal Analysis (OMA) and the comments about the acquired data.
Seismic Response of a Historic Masonry Construction Isolated by Stable Unbonded Fiber-Reinforced Elastomeric Isolators (SU-FREI)
Authors: Castellano Anna , Foti Pilade , Fraddosio Aguinaldo , Marzano Salvatore , Mininno Gemma , Piccioni Mario Daniele
Published: August 2014

We study the implementation of Stable Unbonded Fiber-Reinforced Elastomeric Isolators (SU-FREI) for the seismic protection of a typical historical masonry construction from Puglia. The effectiveness of this innovative isolation technique is analyzed by means of a non-linear dynamic analysis, which shows substantial improvements of the seismic response with respect to the corresponding fixed base construction.
A Wireless Sensor Network Innovative Architecture for Ambient Vibrations Structural Monitoring
Authors: Oikonomou Konstantinos , Koufoudakis George , Kavvadia Eleni , Chrissikopoulos Vassilios
Published: August 2014

Wireless sensor networks can be beneficial for monitoring ambient vibrations in historical buildings where the installation of traditionally wired system may be either difficult due to wiring difficulties or forbidden due to prohibitive legislation. In this paper, a novel wireless sensor network architecture is presented that is focusing on efficiently monitoring ambient vibrations in historical buildings. Traditional wired monitoring technologies are often difficult to be installed in historical buildings either to high costs for installing the wires or to prohibitive legislations. Employing a wireless system could be beneficial. However, as there is no wireless system of high resolution available in the market, an innovative network architecture is proposed that efficiently combines the benefits of both the wired and wireless systems. The problem of synchronization that this novel architecture introduces, is also discussed in this paper along with a possible solution.
Identifying Seismic Local Collapse Mechanisms in Unreinforced Masonry Buildings through 3D Laser Scanning
Authors: Andreotti Chiara , Liberatore Domenico , Sorrentino Luigi
Published: August 2014

The surveys following severe earthquakes show that existing unreinforced masonry buildings are highly vulnerable to local collapse mechanisms. However, their assessment is strongly sensitive to the choice of the mechanism, whose boundary conditions are largely unknown. In the past the mechanism has been selected based on the crack survey alone, because the survey of the deformations is very difficult if traditional tools are used. In the last years advanced survey techniques have been developed, the most powerful of whom resorts to laser scanning. A laser scanner allows the acquisitions of a very large amount of information: building overall dimensions and single elements detailed survey, detection of anomalies, and identification of very limited deformations undetectable with the naked eye. Moreover, contrary to traditional procedures, it allows the survey of the façades without any direct contact with the building, which could be damaged after an earthquake. A laser-scanner survey has been performed in the whole historical centre of Rovere, in the municipality of Rocca di Mezzo, affected by the 2009 L’Aquila earthquake. This survey has been used to study the façades of three different building units, recognising the collapse mechanism triggered by the earthquake ground motion. The mechanisms are fairly different from what suggested by the crack pattern alone and pertain to deformations that cannot be recognised in the photos. Moreover, the faithful geometric models that can be generated from laser scanning allow accounting for deformations and out-of-plumb. Thus, the acceleration activating the mechanism can be estimated much more accurately compared to a perfectly vertical and parallelepiped wall.
Mechanical Characterization of Building Stones through DT and NDT Tests: Research of Correlations for the In Situ Analysis of Ancient Masonry
Authors: Vasanelli Emilia , Sileo Maria , Leucci Giovanni , Calia Angela , Aiello Maria Antonietta , Micelli Francesco
Published: August 2014

In this paper, the use of ultrasonic pulse velocity (UPV) testing as a reliable technique to determine the compressive strength of a calcarenitic stone typical of Salento (South of Italy), known as Lecce Stone (LS) has been investigated. The scope of the experimental research is to establish correlations between the results obtained by non-destructive and destructive tests, in order to reduce the use of destructive methods within the diagnostic procedures for the mechanical analysis and qualification of ancient masonries. Furthermore, the presence of water as a variable affecting the test was investigated. The results of the tests show that the UPV values are well correlated with the compressive strengths and this method showed to be efficient in predicting the strength of LS.
Buildings Behaviour in Urban Fabric: The Safety Assessment Issue in the Post Earthquake Reconstruction Plans
Authors: Lagomarsino Sergio , Cattari Serena , Ottonelli Daria , Rossi Michela
Published: August 2014

This paper is the second one of two companion papers [1] that deal with the experience carried out in the post-seismic reconstruction plans activity in the Abruzzo region done by the research groups of the University of Catania (Coord. C.F.Carocci) and University of Genoa (S. Lagomarsino). In particular, this paper focuses on the issues related to the choice and use of the most suitable modeling strategies and analysis methods to perform the seismic assessment at scale of buildings in aggregate. Both recurring seismic responses of masonry, that is the global one and the local mechanisms, are considered. The strong complementarity with the knowledge phase, faced in detail in [1], is discussed by illustrating an application based on the use of an analytical mechanical model for the in-plane response and that of Macro Block model for the out-of-plane response.
Properties of Geopolymer Concrete from Local Fly Ash (FA) and Palm Oil Fuel Ash (POFA)
Authors: Olivia Monita , Kamaldi Alfian , Sitompul Iskandar R. , Diyanto Ismed , Saputra Edy
Published: August 2014

Geopolymer is an inorganic polymer from activation of source materials that rich of silica and alumina with alkaline activator. Previous studies reveal that the geopolymer has engineering properties and durability, which is equivalent or higher than the Ordinary Portland Cement (OPC) concrete. This paper presents properties of geopolymer concrete prepared with local Palm Oil Fuel Ash (POFA) and Fly Ash (FA) from agro-industrial waste in Riau Province, Indonesia. The POFA and FA were activated by a combination of sodium hydroxide and sodium silicate. The specimens were cured at room temperature for 24 hours before steam cured for another 24 hours at 60OC. Hardened properties namely compressive strength, tensile strength, flexural strength and modulus of elasticity, and water penetration of both POFA and FA geopolymer concrete were determined at 7, 14 and 28 days. Results showed that local POFA and FA as geopolymer source materials could produce mix with strength 19-22.5 MPa at 28 days. The compressive strength, tensile strength, flexural strength and modulus of elasticity of both geopolymer tended to increase slightly with time. In general, the results suggest that the local POFA and FA are potential as source material to produce geopolymer concrete.
Lightweight Geopolymer Binder Base on Sidoarjo Mud
Authors: Triwulan  , Ekaputri J.J. , Huda C.
Published: August 2014

Sidoarjo mud has been a disaster for society and government of Indonesia, but this material contains of SiO2, Al2O3 and Fe2O3 so that significantly to be expected as a potential pozzolanic material. It would be very useful to take the advantages of the material. Moreover, lightweight concrete is widely applied especially at high-rise buildings in order to reduce the risk of earthquake. In general lightweight concrete is made with less Portland Cement associated with lime and pozzolanic materials as a binder. In this paper, calcined-Sidoarjo mud was introduced as pozzolanic material to create geopolymer paste. Geopolymer binders were made with a mixture of calcined-Sidoarjo mud, fly ash and alkaline activator. The specimens were then mixed with a commercial chemical foamed agent to get lightweight geopolymer binders. The results showed that the mixing with the ratio of fly ash : NaOH: Na2SiO3 were 33,3% : 33,3% : 9,52 % : 23,81% and superplasticizer was 2,5% of binder weight achieved the compressive strength of 55,6 MPa. With additional 1% of foaming agent, the compressive strength of lightweight geopolymer binder was 7.1 MPa
Rheology of High Volume Sidoarjo Mud Mortar
Authors: Widodo Teguh Hermawan , Chandra Lucky , Antoni  , Hardjito Djwantoro
Published: August 2014

Previous studies on Sidoarjo volcanic mud have been largely focusing on its use as low-volume cement replacement pozzolanic material and not as a high-volume cement replacement material. This study is intended to study the behaviour of fresh mortar incorporating Sidoarjo volcanic mud as cement replacement in high-volume i.e. 50%, 55% and 60%; and compares the results with the ones of high-volume fly ash mortar. Calcination and grinding were applied as pre-treatment for the mud to make it more reactive. Grinding time was varied into three different grinding time periods from two to eight hours, to vary the particle sizes of the calcined mud. The results show that the finer the particle size of the Sidoarjo volcanic mud, the bigger the flow of the fresh mortar. The flow of fresh mortar containing the Sidoarjo mud is lower compared to those of the ones with fly ash.
The Relationship between Water Absorption and Porosity for Geopolymer Paste
Authors: Farhana Z.F. , Kamarudin H. , Rahmat Azmi , Al Bakri A.M. Mustafa
Published: August 2014

This paper presents an experimental study of the relationship between water absorption and porosity for geopolymer paste. In order to reduce the carbon dioxide (CO2) emissions to the environment, alternatively fly ash was used as binders in making concrete paste. Fly ash is a waste materials produced by combustion of coal at power plant. Geopolymer paste prepared from class F fly ash was obtained from coal power plant and mixed with an alkaline activator. The combination of sodium silicate (Na2SiO3) solution and sodium hydroxide (NaOH) solution were used as alkaline activator. The alkaline activator was prepared 24 hrs prior to use with the ratio of the mixture of Na2SiO3/NaOH is 2.5. Mixed fly ash and alkaline activator placed in moulds and compacted. The samples were kept at ambient temperature in the moulds until it hardened. All the samples were removed from the moulds after 24 hrs. Then, the samples were cured at 60 °C in the oven for 24 hrs. All twelve samples were prepared for water absorption and porosity measurement. The samples were examined after 7, 14, 28 and 90 days in terms of water absorption test and porosity test. It was observed that after day 90 the sample had the lowest water absorption of 3.81% and porosity 3.77%. The sample had the highest water absorption and porosity of 4.65% and 11.95% respectively at day 7. The pore size decreases and the structures became denser. The morphological structure of geopolymer paste pores can be observed by Scanning Electron Microscope (SEM). The porosity and permeability also decreased hence the durability potentially improved. Keywords: Water absorption, porosity, geopolymer, fly ash
Physical and Mechanical Properties of Fired Clay Brick Incorporating with Mosaic Sludge Waste
Authors: Abdul Rahim A.S. , binti Abdul Kadir Aeslina
Published: August 2014

Brick is one of the most common masonry units used as building material. Due to the demand, different types of waste have been investigated to be incorporated into the bricks. Many types of sludge have been incorporated in fired clay brick for example marble sludge, stone sludge, water sludge, sewage sludge, and ceramic sludge. The utilisation of these waste materials in fired clay bricks usually has positive effects on the properties such as lightweight bricks with improved shrinkage, porosity, and strength. Therefore, this study focus on the incorporation of mosaic sludge into fired clay brick. Physical and mechanical properties were conducted such as compressive strength, shrinkage, density and initial rate of suction test. From the results, it shows that brick with 5% of mosaic sludge obtained the best result with highest compressive strength and low initial rate of suction (18.76N/mm2 and 10.08 g/mm2) respectively. Nevertheless, all the other properties for all bricks incorporated with different percentages of mosaic sludge were complied with the standard. In conclusion, mosaic sludge could be an alternative low cost material for brick and at the same time provide a disposal method for mosaic sludge waste.
Effect of Metakaolin on the Strength and Pore Size Distribution of Concrete
Authors: Hashim Zuraidah , Hamid Roszilah
Published: August 2014

Metakaolin, a supplementary cementitious material, together or separately with silica fume and fly ash, has been widely used as a replacement material for cement. This research is to determine the effect of metakaolin replacement of cement (0%, 7%, 9% and 12 %) to the 3, 7, 14 and 28-day compressive strengths of wet cured concrete at water/cement ratio of 0.4 and design strength of 40 MPa. The workability of the fresh concrete was measured through slump and compacting factor tests. Results show that the workability of the fresh concrete decreased up to 80% at metakaolin replacement of 12%. Replacing metakaolin by 12 %, on the other hand, had resulted in the highest compressive strength, which is 48.5 MPa at 28 days compared to control and other percentages of replacement. The porosity measured on the broken samples taken from the compressive strength test shows that the pore diameter size of metakaolin concrete is almost 93% finer than the controlled concrete, which had contributed to the increased in the strength. The use of metakaolin as supplementary cementitiuos material is hoped to be able to replace or stand tall as others similar to it in the market either due to its strength or cost.
Comparison of Linear Interpolation Method and Mean Method to Replace the Missing Values in Environmental Data Set
Authors: Noor Norazian Mohamed , Al Bakri Abdullah Mohd Mustafa , Yahaya Ahmad Shukri , Ramli Nor Azam
Published: August 2014

Data collected in air pollution monitoring such as PM10, sulphur dioxide, ozone and carbon monoxide are obtained from automated monitoring stations. These data usually contained missing values due to machine failure, routine maintenance, changes in the siting of monitors and human error. Incomplete datasets can cause bias due to systematic differences between observed and unobserved data. Therefore, it is important to find the best way to estimate these missing values to ensure the quality of data analysed are of high quality. Incomplete data matrices are problematic: incomplete datasets may lead to results that are different from those that would have been obtained from a complete dataset (Hawthorne and Elliott, 2004). There are three major problems that may arise when dealing with incomplete data. First, there is a loss of information and, as a consequence, a loss of efficiency. Second, there are several complications related to data handling, computation and analysis, due to the irregulaties in data structure and the impossibility of using standard software. Third, and more important, there maybe bias due to systematic differences between observed and unobserved data. One approach to solve incomplete data problems is the adoption of imputation techniques (Junninen et al., 2004). Thus, this study compared the performance between linear interpolation method (imputation technique) and substitution of mean value for replacement of missing values in environmental data set.
Properties of Concrete with Different Percentange of the Rice Husk Ash (RHA) as Partial Cement Replacement
Authors: Abdul Rahim Mustaqqim , Ibrahim Norlia Mohamad , Idris Zulliza , Ghazaly Zuhayr Md , Shahidan Shahiron , Rahim Nur Liza , Sofri Liyana Ahmad , Isa Nur Fitriah
Published: August 2014

The use of pozzolanic material from waste product as partial cement replacement in concrete contribute to reduce the environmental, economic problem through their waste and as well enhance the strength and properties of concrete. Rice husk ash (RHA) is one of the industrial waste that suitably used as a cement replacement due to its pozzolanic properties which can enhance the properties of concrete. In this study, the workability, compressive strength and water absorption of the concrete containg RHA is investigating. The chemical content of RHA also investigated by using X-ray Fluorescence Test (XRF). The different RHA percentage of 5%, 15% and 25% were used in this study with burning temperature 650°C. The concrete cube of size 100 mm x 100 mm x 100 mm were prepared and cured for 7, 14 and 28 days. Based on result, it was concluded that the optimum RHA replacement for cement in this report was 5 %, which provided the highest compressive strength at 28 days.
An Innovation of the Palm Oil Based Wax as Industrial Wax for Machining Prototype Sustainable Products
Authors: Rajamony Bhuvenesh , Mohd Zain Zuraidah
Published: August 2014

Petroleum based wax are used in industries to produce prototype models in machining, educational and training purposes by many types of industries. However the paraffin type of wax is very expensive. Hence an effort was taken to produce palm oil based wax in the way to substitute paraffin wax to an affordable material that will give great savings in cost and time in prototype manufacturing. Palm oil unique composition makes it versatile in any applications such as food manufacturing, health products, cosmetics as well as pharmaceutical industries. Its technical properties make it as preferable as base components in any manufacturing products. With the sustainable ability to recycle the used prototype parts, industries may be able to produce low cost product verification since the palm oil based wax can be reformed to its original structure properties after heating and melting process.