bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Argon Gas Pressure on Optical Properties of Zinc Oxide Thin Films Deposited by RF Magnetron Sputtering Technique
Authors: Gu J.H. , Zhong Z.Y. , Chen S.B. , Yang C.Y. , Hou J.
Published: March 2014

Zinc oxide (ZnO) thin films were deposited by radio frequency (RF) magnetron sputtering technique on glass substrates in pure argon gas. The optical transmission stectra of the films were measured by ultraviolet-visible spectrophotometer. The effects of argon gas pressure on optical properties of the deposited films were investigated. The optical band-gap of the films was evaluated in terms of the Taucs law. The results show that the argon gas pressure has slightly affected the optical band-gap of the deposited films. Furthermore, the refractive index and extinction coefficient of the films were determined by means of the optical characterization methods. Meanwhile, the dispersion behavior of the refractive index was studied by the single-oscillator model of Wemple and DiDomenico, and the physical parameters of the average oscillator strength, average oscillator wavelength, oscillator energy, the refractive index dispersion parameter and the dispersion energy were obtained.
Analysis of Stretching Load in Tension Stretching Process of Aluminum Alloy Thick-Plate by Using Finite Element Method
Authors: Zhang Da Wei , Zhao Sheng Dun , Jing Fei , Zhang Qi , Fan Shu Qin
Published: March 2014

Tension stretching process is an important link in production of aluminum alloy thick-plate. Exploring the change of load in tension stretching process is important for the structure designing and key component checking of large-scale tension stretcher. In this paper, the changing law of stretching force in the tension stretching process of aluminum alloy 6063 thick-plate has been investigated by numerical simulation method, and the influence of initial thickness of plate and friction condition in clamping area was analyzed. The results indicated that the initial thickness has a notable influence but friction condition has a little influence on stretching load; and the stretching force increases at first and then decreases slightly, and then it is tending toward stability; and the larger the values of thickness and friction, the more stable the stretching force in the process.
Research on Crack Damage Identification Based on SFRF and Fiber Bragg Grating Sensors
Authors: Shang Jin , Qin Zi Ming , Wang Xiao Dong , Li Wei , Bai Ya He , Hu Ye Fa , Chen Guo Feng , Li Bin
Published: March 2014

This paper applies strain frequency response function (SFRF), presenting crack damage identification index based on change amplitude of SFRF. Crack propagation identification of four corners fixed thin plate experiment system based on fiber bragg grating sensors is established, experiments and analysis are carried out. Results show that: this crack damage identification system can identify crack damage occurs and propagation effectively.
Study on Distributed Intelligent Control Model of the Ships Pipe Network
Authors: Jin Tao , Zhou Ze Yuan , Yang Feng
Published: March 2014

A MAS-based distributed intelligent pipeline leakage control model, ship pipe network through the intelligent valve control system for automatic, independent isolate damaged sections, thereby enhancing ship in wartime circumstances viability. According to distributed intelligent control pipe network model composed of properties, the Agent is divided into sensor Agent, processors and actuators Agent. Agent of the processor by the sensor data collected Agent independent judgment pipe segment status judgment method and control rules proposed intelligent valve leakage indicator to determine the logic of the other characteristic parameters for a comparative study. Pipeline leakage numerical simulation results show that: the model and control logic to isolate leakage pipe sections, using the model can improve the vitality of ship pipe network.
The Technical Development for Increasing ROP with Particle Impact Drilling in China
Authors: Zhao Jian , Xu Yi Ji
Published: March 2014

Field test of particle impact drilling (PID) technology was firstly carried out in deep well and hard formation in Sichuan province china on Oct. 2013. The test formation was named Xu Jiahe, which was very difficult to penetration. Field test result shows that the ROP (rate of penetration) was nearly doubled by this technology. It indicates that there is a profound application prospect of particle impact drilling, especially for hard rock formation. In this paper, the equipment and working principle was analyzed. The experiment and simulation results showed that the rock breaking efficiency was highly increased by this technology. The details of this field test were presented too in this paper that proved the sound effect of PID.
Investigation of Sound Field with Water Immersion TOFD Method Basing on Electron Beam Welding
Authors: Zhai Jing , Lu Chao , Yu Cheng Long
Published: March 2014

The time and flight diffraction (TOFD) technique has be more and more applied as a well-developed ultrasonic non-destructive testing (NDT) technique in a increasing number of industrial areas such as aeronautics and mechanical industries, therefore, the TOFD technique can be also used to investigate the sound field characteristic curve of artificial defects in welding. The investigations are performed in 2-layered medium (water-steel) with using the finite difference numerical simulation software Wave2000. The receiver group is consisted of several receivers which are immersed in water and have the same frequency, the receivers are placed at the opposite positions by changing regular angle.The results show that amplitude of diffraction wave change along different receiving orientation greatly, if the normal to the vertical direction is set to 0 degree, then the direction of 20° can receive the largest amplitude of diffraction wave. At last, the characteristic curve of diffraction wave is given in this paper.
Study on CNC System for Concave-Convex Surface Processing of Antique Style Flooring
Authors: Jiang Jun An , Wang Yi Ren , Zhao Li Tao , Li Li , Liu Yu
Published: March 2014

As a new emerging kind of flooring, antique style flooring has been warmly welcomed by the market. The production of the flooring is produced through artificial processing only and result in some problems. In this paper, a new patented CNC grinding system is introduced, which makes it possible to process concave-convex surface on flooring automatically. There were two major points in developing the system. Firstly, the concave-convex surface processed by this system must have the same visual effects as those processed in artificial way, denting and protruding randomly and maintaining the natural beauty of wood. Secondly, efficiency was another key point for this system. Research goal was to realize the continuous processing, so that more products could be obtained in a shorter time. Test results show that the system could achieve the original design purpose thus providing with a new technology for concave-convex surface processing of antique style flooring.
Study on Reliability Growth Test Method for Disc Magazine and Manipulator
Authors: Duan Jing Ying , Fu Chang Jing
Published: March 2014

The life distribution model and accelerated life testing methods of the disc magazine and manipulator were discussed. The small sample determination of truncation test was performed to QY011 and a batch of test data under the accelerated stress at the selection of vibration as the accelerated stress have been obtained. The reliability life index under certain stress level was analyzed through established the accelerated probability weighted Weibull model and inversed power law model for acceleration model. According to the acceleration model and statistical analysis of test data, the QY011 reliability life level of QY011 disc magazine and manipulator under the normal working conditions were calculated.
Study on Wear Life Prediction of Wind Turbine Helical Gear
Authors: Wan Shi Qiang , Zhao Chun Hua , Dong Hai Jiang , Wang Wei , Zhong Xian You
Published: March 2014

The paper analyzed on wear failure mechanism of the helical gear of wind turbine. Then, according to the characteristics of the gear transmission, the helical gear integrated wear value was calculated. Considering gear transmission steadily, the ultimate integrated wear quantity was determined by gear transmission accuracy. Finally, the helical gear wear life model was derived, which had an important guiding significance on the wear life prediction of helical gear pair, gear parameter optimization design and wear condition monitoring.
Research on a Flow Resistance Mass Flow Sensor
Authors: Li Xin , Yu Ling , Jia Chun Xue
Published: March 2014

A flow resistance mass (momentum) flow sensor has been designed. The structure and principle of flow sensor are introduced. The testing results show that the flow sensor is excellent in stain resistance, large flow ratio, low power dissipation and long service life. A heatmeter can be achieved using the designed sensor with matching integer operation and display modules.
The Intelligent Control Method of Additive Manufacturing Flow Based on the Measurement of the Line Width
Authors: Wang Rui Yan , Shi Ting Chun , Zhang Yi
Published: March 2014

Based on the closed-loop control theory in the paper, an intelligent control method of additive manufacturing based on the measurement of the line width is studied. The setpoint with the current line width which is scanned by the CCD sensor is compared, the relative relationship between the displacement speed of the forming equipments workbench and the rate of flow of the nozzle could be controlled. The Results of the study shows intelligent control of solid model and scaffoldss accuracy, pores shape and porosity, the forming precision is improved greatly makes the cell differentiation, attachment and crawling easy.
Frequency Dependence Stiffness and Damping of "O" Rubber Ring
Authors: Yan Jiang , Wang Yong Xing , Wang Sheng Ze , Su Xiao Wen
Published: March 2014

In this paper, a mechanical model has been established for elastic support element of high speed winding machine, and an analytical-experimental study has been carried out for the evaluation of frequency dependence the stiffness and damping of the "O" type rubber ring, the key factors which influence the stiffness and damping have been obtained. This lays a foundation for further study on frequency characteristic of kinetic parameters of high speed winding machine elastic support system.
Investigation into the Influence of Drying on Backtrap Mottle of Coated Paper
Authors: Li Jian Guo , Li Ying
Published: March 2014

Ink penetration and distribution affect the final appearance of printing and usage of ink, which are closely concerned by printer and paper maker. The objective of this experiment was to investigate the relationship between drying and back trap mottle. The different drying temperature was carried out to change the coating structure and properties. Fluorescent ink was used to observe and characterize ink distribution by LSCM. The results indicated that drying temperature affected ink distribution evenness. Higher and lower drying temperature could not contribute to ink absorption uniformity. Appropriate drying temperature could contribute to form the best printability of coated paper. Backtrap mottle was tightly linked with ink penetration evenness and uniform ink absorption leaded to little back trap mottle.
Design and Application of the Testing System for a New Pipe Pressure Sensor
Authors: Zhang Xiao Ming , Yuan Yi , Liu Jian Min
Published: March 2014

The new pipe pressure sensor is a clamp-on ICP (Integrated Circuit Piezoelectric) type dynamic pressure sensor, mainly for the clamp-on pressure testing of high pressure fuel pipe. In testing, the vibration of the fuel injection pumps and diesel engine will disturb the clamp-on pressure signals, resulting in one of the measured signal to noise ratio is low, the second is the test system, in particular the signal transmission have a significant impact. In response to these problems, designed a PCI data acquisition card building-in constant-current source and special low pass filter, and developed the corresponding data acquisition software based on C++ Builder. The bench and real vehicle testing show: the test system can better fit with the new type pressure sensor to obtain accurate clamp-on pressure signals.
Research on Metal Ring Strain Energy Power Loss of MB-CVT
Authors: Zhang Wu , Guo Wei , Zhao Shuan Feng
Published: March 2014

This paper proposed a metal belt continuously variable transmission (MB-CVT) model on the basis of elastic mechanics theory to describe the strain energy power loss (SEPL) of metal rings. The metal rings were simplified as combined thin wall cylinder model in the arc part and simple tension model in the straight part. The results show that, the SEPL scope of the metal rings are 27.15-86.73W, the SEPL reduced when the transmission ratio is 1. This result shows a well agreement with the theory analysis.
Research on Load Bearing Behavior of Ship Stiffened Plates under Cyclic Loads
Authors: Cui Hu Wei , Yang Ping , Shen Can , Zhou Liang
Published: March 2014

This paper adopts nonlinear finite element method to study the load bearing behavior of ship stiffened plates with different dimensions. The research focuses on the compressive ultimate strength, axial rigidity, and residual plastic deflection of the stiffened plates under cyclic compressive and tensile loads. The results indicate that the compressive ultimate strength and axial rigidity of stiffened plates decrease with the incremental cyclic loads significantly, meanwhile, the residual plastic deflection increases with the cyclic loads.
Study on Ship Hull Deformation by Integrated Model of Hull with Shaft
Authors: Ruan Xiang Kui , Yang Ping , Yan Xin Ping , Huang Zhe
Published: March 2014

Hull deformation directly influences the working condition of propulsion shaft, so that the reasonable and accurate calculation of deformation is the basic content of research on ship propulsion system. This paper, basing on a large container ship, built up an integrated finite element model of the hull with the propulsion shaft. By employing inertial relief method, the hull deformation at place of shaft supports is calculated under different loading conditions. The results are compared with those from a hull FEM model without shaft. Some valuable conclusions are made from the results analysis.
Numerical Simulation of Geomembrane Defect Leakage by Saturated-Unsaturated Seepage Method
Authors: Gan Lei , Shen Zhen Zhong , Yan Zhong Qi , Ren Hua Chun
Published: March 2014

For the leakage problem caused by geomembrane defect, the unstable saturated-unsaturated seepage theory and Galerkin finite element method have been adopted. So a three-dimensional finite element numerical model of an earth-rock dam with geomembrane anti-seepage system is simulated by the unstable saturated-unsaturated seepage finite element method. The influnence on seepage field for the varying degrees of geomembrane damage is analyzed, and the overall and local seepage field characteristics of the dam for geomembrane defect leakage are discussed. The results show that the numerical method provides an effective way to study the leakage problem of geomembrane defect.
One Kind of Mould's Geometrical Modeling and Finite Element Analysis
Authors: Guo Zhen Long , Zhao Hong Sheng
Published: March 2014

This paper, by using large-scale finite element analysis software Ansys and assuming that the lining of a mould is under uniformly distributed load, analyses the stress and deformation and on the basis of the result gives an overall optimization design.
Effect Sedimentation of TiB2 Particles on the Microstructure of 7075 Al Alloy
Authors: Gan Gui Sheng , Gao Qian , Yang Bin , Gan Shu De
Published: March 2014

Novel reactive technique has been employed in synthesis of 7075 Al matrix composites and sedimentation of TiB2 particles were studied by viscosity test. Researches have shown that most TiB2 particles reached about 900~1400nm in 3%TiB2/7075 composites, and about 600~800nm when the content is up to 6% TiB2 particles. The grain size of the 3%TiB2/7075 composites became the rosette from dendrites in 7075 Al alloy, but α-Al became the dendrite after added 6%TiB2 in 7075 Al alloy. After viscosity test, nearly spherical grains and gross dendrites can be found above and below the boundary layer respectively. Grain size in 6% TiB2/7075 composites was relatively smaller than 3% TiB2/7075 composites at the same position.
Crack Initiation Life Model of Stiffened Plates Based on Damage Mechanics
Authors: Wang Hong , Yang Ping , Deng Jun Lin , Dong Qin
Published: March 2014

Based on the continuum damage mechanics theory, according to the development of the fatigue damage evolution equation, and combining the interaction coefficient of stiffener and plate, with plastic strain as the control quantity of damage evolution, the stiffened plate low cycle fatigue damage mechanics model is established, and the calculation method of the fatigue crack initiation life is obtained. This method for the initiation life of fatigue crack is divided into the life before the damage and the life of the damage evolution. The model results are compared with those of the finite element results. Conclusions show that the model can reflect the regularity of axial plastic strain evolution of stiffened plate, and can be directly used for fatigue loads analysis under the mechanism of initiation life.
A Highly Efficient Deaerator Design and Application
Authors: Jiang Pei , Ji Qing , Zhou Hao , Dong Li
Published: March 2014

In this paper, in view of the non-condensable gas in the process condensate can not effectively remove in industrial boiler, designed has developed a new type of high efficient deaerator. Three times the gas-liquid separation process can ensure the effective clutter the impurity gas discharge in this deaerator. When the condensation temperature is below 80 °C, standby mouth additional blower can be further improved degassing efficiency. The body of tank is designed by the liquid levels frequency conversion control and the upper tank provided with an overflow pipeline, to ensure the separation of the impurity gas, but also guarantee the safe operation of the system.
The Drug Loading Kinetics Mechanism of Ion Exchange Fiber as a Novel Kind of Drug Carrier Material
Authors: Yao Hui Min , Zhu Jun Yi , Xia Guang Qing
Published: March 2014

The adsorption of Fenazoxine hydrochloride was investigated by performing batch kinetic sorption experiments. Experiments were carried out as function of contact time, initial concentration. Adsorption data were modeled using the pseudo-first-order and pseudo-second-order kinetics equations. It showed that the pseudo-second order kinetic equation can describe the adsorption kinetics best. The results indicate that ion-exchange fiber is suitable as drug carriers for loading drugs.
The Research of Poly Propylene Carbonate /Nano-SiO2 Composites
Authors: Li Qu , Wu Heng , Xie Si Yuan , Sun Jiao , Liu Xing Hai , Li Hou Bin
Published: March 2014

Biodegradable poly (propylene carbonate) (PPC) composite with a slight improvement in the thermal stability and tensile strength was successfully prepared by incorporating a low content of nano-SiO2. Tensile tests demonstrate the better mechanical properties of the composites prepared in this study. The obtained composites increases sharply from 1.57Mpa to 12.04Mpa by incorporating 5wt% nano-SiO2. Furthermore, the composites show approximately 8°C higher glass transition temperature (Tg) than that of neat PPC.The Tdmax of composite with 5wt% of nano-SiO2 was about 40°C higher than that of neat PPC.
Preparation and Wide Tunable Band-Gap Energies of PbTe Nanocrystals Using Glycerin as a Capping Ligand
Authors: Ren Xing Li , Jiang Xing Rong
Published: March 2014

PbTe nanocrystals (NCs) have been synthesized by a novel method at low temperature. Pb acetate being solved in glycerol and Te in TOP solution were used as the precursors for the preparation of PbTe nanocrystals. The as-prepared products were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), UVvis absorption, Fourier transform infrared spectroscopy (FTIR). These data, together with analysis of the absorption spectra, allowed us to observe the size dependence of the peaks in the absorption spectrum. The size-dependent optical spectra of the PbTe nanocrystals exhibits wide tunable band gap energies varying from UV visible range to near IR region, which corresponds to a huge blue shift of 3.0 eV in comparison to the bulk counterpart. Keywords: 1. PbTe nanocrystals, 2. optical properties, 3. wide tunable band gap, 4. microstructure
Nanoemulsion Synthesis of Magnetic-Optical CoNiAu Nanoparticles
Authors: Shao Hong Qin , Guan Zheng , Wu Jun Hua , Liu Hong Ling
Published: March 2014

Multi-functional CoNiAu nanoparticles were successfully synthesized via nanoemulsion method with the use of PEO-PPO-PEO as the surfactant, C14H29CH(OH)CH2OH as the reducing agent, Ni (acac)2, Co (acac)2 and Au (ac)3 as precursors. The characterization of the CoNiAu nanoparticles was performed using X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and UV-vis near IR spectrophotometer (UV-vis). The XRD and TEM analysis confirm the formation and structure of the nanoparticles. The UV-vis and VSM measurements display the optical and magnetic properties of the CoNiAu nanoparticles at the room temperature. The CoNiAu nanoparticles with the well defined optical and magnetic properties are promised for optical, magnetic, catalytic and biomedical applications.
Study on a New Coumarin Derivative as Fluorescent Probe for Hg2+ Ions
Authors: Li Hong Qi , Chen Zhen , Chen Hao , Zhang Jia Wei , Chen Yan Tai , Bi Jun Min , Zhou Ming
Published: March 2014

A new coumarin derivative L was synthesized and characterized by 1H NMR, 13C NMR, IR and mass spectrum. UV-Vis and fluorescence emission spectra of L without or with different anions (NO2, F, Cl, HSO3, HSO4, AcO or NO3) or metal ions were measured, which showed while addition of anions or metal ions Mg2+, Zn2+, Ca2+, Cu2+, Ni2+, Co2+, Fe3+ or Al3+ led to decrease in intensity of the maximum emission peak at about 480 nm, addition of Hg2+ ions caused increase in intensity of the maximum emission peak, suggesting that L may act as a fluorescent probe for detection of Hg2+ ions.
Elastic Properties of Thermo-Hydro-Mechanically Modified Bamboo (Guadua angustifolia Kunth) Measured in Tension
Authors: Archila-Santos Hector Fabio , Ansell Martin Philip , Walker Peter
Published: March 2014

Guadua angustifolia Kunth (Guadua) was subjected to thermo-hydro-mechanical (THM) treatments that modified its microstructure and mechanical properties. THM treatment was applied to Guadua with the aim of tackling the difficulties in the fabrication of standardised construction materials and to gain a uniform fibre density profile that facilitates prediction of mechanical properties for structural design. Dry and water saturated Guadua samples were subjected to THM treatment. A densified homogenous flat sheet material was obtained. Mechanical properties of small clear specimens of THM modified Guadua were evaluated by testing in tension and compared to the results of the same test on a control specimen. Samples were tested in the elastic range to determine values for Modulus of Elasticity (MOE) and Poissons ratio. There was a significant increase in the tensile MOE values (parallel to the direction of the fibres) for densified samples. MOE values measured were 16.21 GPa, 22.80 GPa and 31.04 GPa for control, densified dry and densified water saturated samples respectively. Oven dry densities for these samples were 0.54 g/cm3, 0.81 g/cm3and 0.83 g/cm3. Despite a 50 % reduction in the radial Poissons ratio for the water saturated sample, no further variation in the Poissons ratio as a result of densification was observed for control and densified dry samples. This paper presents the results of the first phase of a study focussed on the manufacturing of flat Guadua sheet (FGS) by THM treatment and the characterization of its mechanical properties. The achievement of a dimensionally stable FGS by THM modification, with a uniform density and achieved with reduced labour effort during manufacture, will be of key importance for the development of structural applications, and could have a significant impact in the bamboo industry. The final aim of the research at the University of Bath is the development of Cross Laminated Guadua (CLG) panels using THM modified and laminated FGS glued with a high performance resin.
Building with Earth - Brazil's Most Popular Raw Earth Building Techniques and the Opinion of Experienced Builders
Authors: dos Santos Clarissa Armando , Librelotto Lisiane Ilha , Jacintho Claudio
Published: March 2014

Earth building construction techniques bring the promise of being environmentally friendly, thermally comfortable, easy to maintain and aesthetically interesting. Therefore, the ideae is beginning to spread in Brazil, being divulgated mainly by institutes and groups involved with Permaculture studies. The possibility of building sustainably and independently has contributed to the increasing number of people embracing the cause and starting constructing with earth and other raw materials. But what are their opinions after the end of the process? This work brings a review on some of the most popular earth building techniques in the Brazilian Federal District and state of Santa Catarina (superadobe, hyperadobe, rammed earth, cob, stucco, and double stucco filled with plastic bottles), as well as interviews with builders and users of the resulting houses. The research showed that the houses were built mostly by the owners themselves, with only a few having relied on professional help at some point. The drawbacks appointed were the lack of qualified professionals well-acquainted with these building techniques, the difficulties in managing large groups of voluntary builders and the high physical effort demanded by some of the techniques. Actually, many houses were composed by more than one technique. Some were built using a different technique to each wall. Superadobe was the preferred one at first, however most builders decided to change to other techniques for the practicability or just for the sake of experimenting. The experimenting of different techniques was more frequent in the cases when the house was the first construction of the builder (s). Unfortunately, the lack of experience had serious consequences, for it was noticed that some buildings showed construction pathologies, such as pending walls and peeling plasters. Nonetheless, most of the users declared to be satisfied and considered earth building a good investment. In fact, the houses had good thermal performance, used low impact materials and had a medium cost of approximately BRL 310.00 per square meter. A considerably lower price than the average BRL 670.00 per square meter, estimated by Brazilian authorities for the same locations and building patterns at the time of the constructions.
Comparing the Environmental Impact of Stabilisers for Unfired Earth Construction
Authors: Maskell Daniel , Heath Andrew , Walker Pete
Published: March 2014

Buildings account for approximately one third of the total worldwide energy emissions, of which approximately a quarter can be attributed to the embodied energy of the building. Current UK legislation for low-energy homes is only concerned with operational energy. Embodied energy, and carbon, is not currently considered but over the design life of an average building is expected to make a significant contribution to the total whole life energy used. Earthen building materials contribute to reduce energy consumption in use through their passive regulation of temperature and humidity. In addition, there can also be significant embodied energy savings compared to other materials. Traditional methods of earthen construction, using locally sourced materials and manual labour require minimal energy for the transport and construction. A greater uptake of earth construction is likely to come from modern innovations such as industrialised manufacture. Extruded fired brick manufacturing processes has the potential to produce a high quality, low cost and low energy product suitable for the mainstream construction sector in both developed and developing nations. By not firing the extruded clay bricks, an embodied energy saving of 86% can be achieved, compared to fired clay, and 25% compared to concrete blocks. However, there are limitations to the structural use of unstabilised earth bricks due to the loss of strength under high moisture content conditions. The use of traditional and novel stabilisation methods can be adopted to address the concerns over strength and durability. Cement and lime are widely used in some countries, but both significantly increase material embodied energy and carbon and can inhibit passive humidity regulation. The paper presents results from a study of the embodied energy of various stabilisers used for unfired clay materials. The Global Warming Potential (GWP) is a measure of the equivalent carbon dioxide that allows for the relative weightings of damaging greenhouse gasses. Both the embodied energy and the GWP figures of various stabilisers are compared and discussed. The conclusion of the work is that there is a maximum quantity of stabiliser than should be used. Typically the quantities of stabiliser are quoted as the amount that gives the maximum strength, but this should take account of not only strength but the environmental impact of achieving the improvement.
Feasibility Study of the Manufacturing Process of Soil-Cement Blocks for the Construction of Masonry Aiming to Eliminate the Settling Mortar Application
Authors: Fay Liliana , Cooper Paul , Lana Luiz Henrique , Souza Danilo Pereira
Published: March 2014

The growing industrialization of the construction materials, the evolution of the construction techniques and ease for conveyance, broadly speaking, eliminates the need to use local materials for construction. However, the earth still presents itself as a material with the potential to reintroduce the old and healthy construction habits, yet without precluding the search for technical innovations consistent with good environmental practices, and that may contribute to the formulation of simpler and cheaper processes. The current work developed the morphology of a new component of construction made with an easy acquisition and low cost material: soil-cement, a material and procedure proven, tested, and regulated. The redesign of a new construction component aims to facilitate the rise of the masonry through an innovative construction process, in which the settling mortar can be eliminated with a perfect fitting system. With the fitting block designed, the mould for pressing was then developed and prototypes were conformed, experimentally, in three soil-cement mixtures showing production feasibility. The prototypes were tested according to the related standards, being submitted to tests of resistance to compression, water absorption and sizing. The results showed that only the water absorption parameter did not comply with the standards and therefore must be targeted by future researches in order to improve the mixture composition.
Geopolymer Stabilisation of Unfired Earth Masonry Units
Authors: Maskell Daniel , Heath Andrew , Walker Pete
Published: March 2014

Contemporary domestic structures typically use masonry units that are approximately 100mm thick. There is interest in using commercial methods of manufacture to produce earthen bricks that have a similar form factor to conventional masonry The large scale adoption of thin walled unfired earth masonry is dependent on its suitability for use in a load bearing application. High moisture content leading to full saturation, for example as a result of flooding, is a concern for unstablised earth construction, especially as wall thickness reduces. The greatest barrier for earth masonry adoption is the durability of the material when affected by high moisture content. Accidental and intentional wetting of a 100mm thick load bearing unfired earth wall could lead to disproportionate collapse. The paper presents initial findings from an investigation into the use of geopolymer mechanism as a method of stabilisation. The use of geopolymer mechanism was chosen as a possible method of improving the water resilience. Soil that is used for commercial extruded fired brick production was chosen. The soil was selected as the precursor (source of the required silica and alumina) and this was mixed with various sodium hydroxide and sodium silicate activators. Specimens were tested both in their dry sate as well as following 24 hours of submersion in water. Compressive strength of cylinders after saturation, was used as an indicator of effective stabilisation. The maximum dry compressive strength achieved was 10.4N/mm2with the addition of 5% sodium hydroxide and 20% sodium silicate after curing at 105°C. The most significant contributor to the strength gain was the addition of sodium silicate. Although some of the cylinders were able to be tested under fully saturated conditions the strengths achieved were negligible and insufficient for structural application. The potential for geopolymers as a method of stabilising unfired earth bricks is discussed with respect to the compressive strengths achieved.
Preliminary Evaluation of the Adoption of Machines for the Partial Mechanization of Adobe Production
Authors: Joaquim Bianca dos Santos , Lopes João Marcos de Almeida
Published: March 2014

Earth as a construction material is being announced as capable to answer the construction sectors demands with considerable reductions on environmental impacts. It is an abundant raw material, commonly available at the construction site, which requires low energy consumption to be produced or transformed and which also doesnt need to be fired, what means that its production emits very small amounts of CO2. In terms of results for the built environment, it may provide excellent thermal and acoustic comfort, besides contributing to regulate the environments humidity. At the end of its cycle the material can be discarded bringing no harm to soil and water, it is rapidly absorbed by the environment conversely, it can be recycled by turning it into mud again, so it can be used to prepare new construction elements. However, in Brazil and in many other developing countries, the application of the earth construction technologies usually occurs as handmade work. Particularly on the adobe production, the blocks are mostly molded one by one or in pairs, depending on the type of the molds, aiming to accomplish a production of thousands of unities. The soil used for block molding has to be in a plastic consistency and, to achieve that quality, intensive human effort is generally employed. Considering those difficulties this paper intends to present an initial roll of machines used on production processes of Brazilian construction sector, and other industrial sectors, that can be integrated to adobe fabrication procedures to help mixing the mud. From the collected information, a preliminary evaluation will be formulated revealing which of the equipment contribute effectively for the comfort and safety of workers. Another factor that may be considered for this selection is the investment amount needed. As high costs interfere with the control of the means of production, the workers may have their access to this condition denied, situation that affects the possibility of social advances that can be promoted by the appliance of adobe.
Reinforcement of Adobe Constructions with Toad Rush Mesh
Authors: Méndez María Teresa Landa , Mora Ronny Soto , Sosaya del Carpio Luis Gustavo
Published: March 2014

Peru has a long history of mud constructions. The use of these techniques has been forgotten throughout time, and currently the adobe buildings lack a constructive system suitable for our seismic, economic and ecological characteristics. Current solutions to this problem, including the countrys normative, alter its natural characteristics and make it more expensive. To achieve a way of life that integrates cultural identity, dwelling, environment and health, a natural material of easy acquisition is studied: the toad rush (Juncus bufoniusL.) It is a plant that grows in humid areas of the country, between 0 and 4 000 AMSL, in order to address its use as reinforcement in the walls of adobe, based on structural proposals approved in Peru. An experimental methodology has been used under the modality of trial and error. The study was performed in three stages; in the first one, its elasticity coefficient and resistance to traction was determined in laboratory tests. The analysis were performed on simple fibers and braids (of up to 6 fibers), finding the following results: elasticity modulus = 36 kPa with 5% strain, maximum tension stress = 745 N in both directions with 12% elongation. Using these data, an orthogonal mesh of toad rushes, with 0.030 m of separation between braids, was designed to be attached to an adobe wall. This mesh was subjected to a test of horizontal impact, applying 84.49 MPa as a maximum force. In a third stage an adobe module of 2.40 x 2.40 x 2.40 m reinforced with the mesh was subjected to a mechanical seismic simulation test, supporting 26.1 kN without the mesh suffering any damage. As a last test, to comply with the requirements laid down in annex N°1 of the E.080 RNE of the Peruvian standard, a real scale module (2.40 x 2.40 x 2.40 m), was subjected to a cyclic test at the CISMID-UNI laboratory. The results showed that under a distortion from 1/1100 to 1/500 micro cracks were generated in the walls. Under a distortion of 1/400, 0.005 m cracks occurred at the bottom of the north side of the model and under a distortion of 1/280 the model suffered the detachment of the plaster of the lintel, without any damage to the mesh. All the tests allowed for the conclusion thatthe toad rush(Juncus bufoniusL.) is a material that,used as a mesh,can be used asreinforcement in adobe buildings. It is elastic and resistant to traction. It has as an advantage that it is very accessible, known throughout the country and easy to work with. The tests allowed us to proof the resistance of the toad rush mesh, in spite of the features of the adobe not conforming to the Peruvian standard E.080 RNE. We conclude that: it is feasible to use a mesh of toad rush (Juncus bufonius L.) as reinforcement in adobe buildings.
Magnesium Oxysulfate Fibercement
Authors: Gomes Carlos Eduardo Marmorato , Camarini Gladis
Published: March 2014

Recently the use of alternative binder has been verified in several applications like roofing, sheets, panels and refractory. Thus, in this work the authors show results of some properties of Magnesium Oxysulfate Cement reinforced by fibers, specially traction in flexion and durability. MOS cement are formulated and governed by reactions like acid-base between magnesium oxide and magnesium sulfate solution. Some properties as abrasion resistance can be until 1.5 times that of Ordinary Portland Cement. Furthermore its compressive and transverse strengths are also higher than OPC. In the USA and Europe the major use of MOS cement is in the manufacture of lightweight insulating panels. In order to evaluate MOS cement properties, it was analysed two different matrices reinforced by polymeric and cellulose fibers. Calcium carbonate was employed as filler. Tests showed good mechanical behaviour, durability, and the possibility of using MOS fibercements as an alternative for non-asbestos products.
Pozzolanic Reaction Effects of Red Mud on Hygrothermal and Microstructural Properties of Cementitious Composites
Authors: Manfroi Eliz Paula , Cheriaf Malik , Rocha Janaíde Cavalcante
Published: March 2014

The alumina industry produces the red mud (RM) as one of its by-products. The red mud waste has pozzolanic potential, mainly when calcined at 600oC. In this paper, the microstructure of cement pastes constituted by 15% of dry and calcined red mud at 600, 700, 800 and 900oC were investigated by scanning electron microscopy analysis. To assess the evolution of the heat of hydration of pastes produced with until 15% of red mud in replacing the cement was used a semi-adiabatic calorimeter. Water absorption by capillarity and wetting angle tests were realized on mortars constituted by 5 and 10% of red mud in replacement of cement. The images of the microstructures of the pastes produced with red mud showed the formation of the hydration products calcium silicate hydrate, fase AFm (monosulfate) and ettringite. The pastes produced with 5, 10 and 15% red mud showed higher heat of hydration than the reference pastes (only cement). The mortars produced with 5% of dry and calcined red mud at 600, 700, 800 and 900oC showed lower sorptivity than the reference mortar. The results shown that the replacement of the cement by red mud waste influence in the hygrothermal and microstructural properties of cementitious composites.
Study of Geopolymeric Binders of Fly Ash/Metakaolin Mixtures Cured at Room Temperature
Authors: de Vargas Alexandre Silva , de Gutierrez Ruby M. , Castro-Gomes João
Published: March 2014

Geopolymerization is a chemical process in which aluminosilicate materials are precursors to obtain binders that have a low environmental impact. Fly ash has been used as a precursor for the development of these binders. However, thermal curing is needed to accelerate the polycondensation of aluminosilicate, which limits the application of this new binder in the construction industry. Thus, the objective of this study was to evaluate the feasibility to obtain such binders with good mechanical properties when cured at room temperature. The precursor material consisted of different mixtures of fly ash and metakaolin that were activated using combined sodium hydroxide and sodium silicate alkaline solutions. The effect on the compressive strength of different proportions of the alkaline solutions was studied. Compressive strengths of about 40 MPa were achieved at 91 days for the samples containing 70% fly ash and 30% metakaolin, activated using an alkaline solution of 50% sodium hydroxide and 50% sodium silicate. X-ray diffraction analysis showed the formation of natrite in geopolymeric samples, as well as the presence of crystalline compounds, such as quartz, mullite and hematite, in fly ash and metakaoline. Scanning electron microscopy analysis showed that in geopolymeric mixtures with higher compressive strength dissolution of fly ash and metakaolin particles occurred almost completely and that aluminosilicate dense gel has been formed extensively.
Supercritical Carbonation of Lightweight Aggregate Containing Mortar: Thermal Behavior
Authors: Lima Filho Marçal Rosas Florentino , Torres Sandro Marden , Black Leon , de Araújo Porto Vieira Andressa , Gomes Rodinei Medeiros , Gomes Kelly Cristiane
Published: March 2014

Lightweight concrete shows good insulation properties, depending on several parameters such as mix design and aggregate type. Perlite aggregate is one of the most effective aggregates for such a purpose, mainly because of its low thermal conductivity (0.04 W/m.°C), but is not available globally. This paper explores the potential use of another source of thermal efficient aggregate, vermiculite (0.058 W/m.°C) which is available in Brazil and other countries where perlite is absent. Cylindrical samples were cast by using two lightweight aggregates, perlite and vermiculite, and treated with supercritical carbon dioxide. Supercritical carbonation (SCC) of concrete can improve mechanical, thermal and durability features. In this paper, the effect of SCC on the thermal behavior of lightweight mortars was investigated with regards to physical and microstructure features and thermal behavior due to cooling.
The Influence of the Fineness of Mineral Additions on Strength and Drying Shrinkage of Self-Compacting Mortars
Authors: Menadi Belkacem , Kenai Said , Hammat Sihem , Khatib Jamal M.
Published: March 2014

Self-compacting concretes are extremely fluid concretes that can be placed into formwork without vibration. They are characterized by the presence of mineral additions which influence considerably their behavior in fresh and hardened states. This paper reports the results of an experimental study on the influence of Ground Granulated Blast Furnace Slag (GGBFS) and natural pozzolana (NP) and the effect of their fineness on the compressive strength and shrinkage of self-compacting mortars. Each addition was ground to three finenesses 350, 420 and 500 m2/kg. The cement is substituted by 0%, 15% or 30% of GGBFS. The water to binder ratio was kept low at 0.40; cement content and superplasticizer were maintained constant for all mortars mixtures. The results show that the substitution of cement by mineral additions (slag and natural pozzolana) generates a reduction of the total shrinkage (at 28 days) and compressive strength of self-compacting mortars, whatever the fineness of the addition. The study also showed that the increase of the fineness of the natural pozzolana gives an increase in both drying shrinkage and compressive strength. However, the increase of the fineness of slag decreases slightly the shrinkage and the compressive strength of self-compacting mortars.
Effect of Sisal Fiber Hornification on the Fiber-Matrix Bonding Characteristics and Bending Behavior of Cement Based Composites
Authors: Ferreira Saulo Rocha , Lima Paulo Roberto Lopes , Silva Flávio Andrade , Toledo Filho Romildo Dias
Published: March 2014

Cycles of wetting and drying can change the microstructure of vegetable fibers through a mechanism known as hornification, which modifies the polymeric structure of the fiber-cells resulting in a higher dimensional stability. In the present work the influence of hornification on the sisal fiber-matrix bond adhesion as well as in the sisal fiber dimensional stability and mechanical behaviour under direct tension was evaluated. Furthermore, cementitious composites reinforced with randomly dispersed hornified sisal fibers were developed and characterized under bending loads. The results show that the tensile strength and strain at failure of the hornified sisal fibers were increased by about 5% and 39%, respectively, whereas the modulus of elasticity was reduced by 9%. The fibers also presented higher dimensional stability with the hornification process. The fiber-matrix bonding was improved and the pull-out resistance of the fibers submitted to ten cycles of wetting and drying was increased by about 40% to 50%. The higher fiber-matrix bond strength contributed to an increase in the ductility and post-cracking behaviour of the composite. The fracture process was characterized by the formation of multiple cracks with the hornified sisal fibers presenting a higher ability to bridge and arrest the cracks.
Behavior of Sisal Fiber Mat Reinforced Alkaline Activated Metakaolin Matrix under Direct Flame
Authors: de Sá Teles e Lima Gabriel , Torres Sandro Marden , Gomes Kelly Cristiane , de Barros Silvio Romero , Leal Antônio Farias , Lima Filho Marçal Rosas Florentino
Published: March 2014

Biodegradable containing composites are increasingly present in several industries, mainly because they are renewable but also for their engineering properties. Despite environmentally friendliness has become an issue of paramount importance, the use of natural fibers has some limitations, especially when high temperature exposure is concerned. Geopolymers are known to withstand temperatures as high as 1000°C, preserving significant mechanical properties. This paper aims to explore the potential use of sisal fiber reinforced alkaline activated in high temperature environment. The composites were exposed to direct flame and visual changes and temperature profile were assessed up to 35 minutes. The results shows that material behavior works as an insulation barrier with a c.a. 80% temperature reduction between the direct flame exposed surface to the opposite side. Also, samples with thickness above 5mm maintained their integrity without developing smoke or spreading flame throughout the study time.