bluuebunny/crossref_metadata_2025 huggingface dataset:
El "Sueño de Barrio" ¿Un nuevo modelo de Trabajo Social?
Authors: Munté Pascual Ariadna , Vicente Zueras Irene De
Published: November 2012

A menudo se plantea una disyuntiva de elección entre los diferentes métodos clásicos de intervención social, como si el uso del uno o del otro fuera necesariamente excluyente. El presente artículo muestra cómo la integración de los tres métodos en una misma intervención puede darse sin ningún tipo de conflicto metodológico, si se parte de un marco teórico o modelo de referencia que contemple esta posibilidad. Tras una parte introductoria sobre la noción de modelo en Trabajo Social y sus distintas aplicaciones, se describe y analiza la profunda transformación social de dos vecindarios de la provincia de Albacete en España. Se muestra el proceso seguido por la comunidad y las familias, extrayendo una serie de conclusiones y llegando a un interrogante que invita a seguir investigando sobre este nuevo marco de intervención vehiculado por el denominado Contrato Dialógico de Inclusión Social.
Serological survey on Ehrlichia sp. among dogs in the central region of Rio Grande do Sul
Authors: Krawczak Felipe da Silva , Labruna Marcelo Bahia , Sangioni Luís Antônio , Vogel Fernanda Silveira Flores , Soares João Fabio , Lopes Sônia Terezinha dos Anjos
Published: November 2012

A serological survey on Ehrlichia canis was conducted among dogs in the central area of the state of Rio Grande do Sul, where the tick Rhipicephalus sanguineus is a common parasite of dogs. Out of a total of 316 dogs attended at the veterinary teaching hospital in the municipality of Santa Maria, only 14 (4.43%) reacted positively to E. canis antigens in the indirect immunofluorescence assay, with the following endpoint titers: 80 (three dogs), 160 (five), 320 (four), 640 (one) and 1280 (one). Like in previous studies in other regions of the state of Rio Grande do Sul, only a very small portion of the dogs in Santa Maria presented antibodies reactive to E. canis, even though canine infestations due to R. sanguineus are very common in this study region. These results contrast with other regions of Brazil, where E. canis is endemic among canine populations, with seropositivity values generally higher than 30%. Genetic differences among the R. sanguineus populations in South America might be implicated in these contrasting results.
Risk factors associated with Toxoplasma gondii seroprevalence in goats in the State of Paraíba, Brazil
Authors: Santos Carolina de Sousa Américo Batista , Azevedo Sérgio Santos de , Soares Herbert Sousa , Higino Severino Silvano dos Santos , Pena Hilda Fátima de Jesus , Alves Clebert José , Gennari Solange Maria
Published: November 2012

A cross-sectional study based on planned sampling was carried out to determine flock-level risk factors associated with Toxoplasma gondii antibody prevalence in dairy goat flocks in a semiarid region of northeastern Brazil. Serum samples from 975 adult dairy goats from 110 flocks were examined by indirect immonufluorescent antibody test (IFAT), using cut-off point at 1:64 dilution. From the 110 flocks, 77 presented at least one seropositive animal, corresponding to a prevalence of 70% (95% CI: 60.5-78.4%). Out of the 975 animals, 177 (18.1%; 95% CI = 15.8-20.7%) tested positive. The presence of toxic plants (OR = 5.11; P = 0.045) and the fact that goat breeding is not the main activity on the farm (OR = 3.34; P = 0.014) were identified as risk factors. The results of the present study showed evidence of the presence of T. gondii infection in dairy goats from a semiarid region of northeastern Brazil using planned sampling. Further studies are needed to elucidate the importance of the identified risk factors in the epidemiology of the infection.
First record of Parakosa flexipes (Acari: Chirodiscidae) parasitizing a free-tailed bat (Chiroptera: Molossidae) in Brazil
Authors: Gomes Luiz Antonio Costa , Silva Roberta Mariano , Melo Vanessa Lazaro
Published: November 2012

The present study reports the occurrence of Parakosa flexipes (Pinichpongse) (Chirodiscidae) for the first time in Brazil, along with its infection sites on Molossus rufus E. Geoffroy. Thirty-eight bats were caught using mist nets that were placed near a house at the Mars Center for Cocoa Science in the state of Bahia, of which 14 (37%) were parasitized by P. flexipes. Parakosa flexipes was observed parasitizing M. rufus on hairs that were evidently longer than others distributed over the bat's body, where up to three parasites could be spotted on a single hair.
Strength of a clay soil and soil–cement mixture with resin
Authors: Estabragh Ali R. , Naseh Mohammad , Beytolahpour Iman , Javadi Akbar A.
Published: November 2012

A series of laboratory experiments were carried out to investigate the effect of resin on the strength of a clay soil and soil–cement mixtures. One group of tests were carried out on samples of the clay soil that were prepared with different resin contents. Another group of tests were conducted on mixtures of soil–cement and soil–cement–resin with specified resin contents. The results show that adding more than 10% resin increases the strength of the soil, whereas at resin contents below 10% no significant effect was observed. The strengths of the samples of soil, soil–cement mixture and soil–cement–resin mixture increased with increasing percentages of cement and resin. The results also show that the increase in strength is a function of percentage of agents and curing time.
NADPH Oxidase Activation: A Mechanism of Erectile Dysfunction in a Rat Model of Sleep Apnea
Authors: Liu Kui , Liu Xian‐Sheng , Xiao Li , Shang Jin , Li Ming‐Chao , Xu Yong‐Jian , Liu Hui‐Guo
Published: November 2012

Abstract: Erectile dysfunction (ED) is a frequent occurrence in male patients with obstructive sleep apnea syndrome (OSAS). Long‐term intermittent hypoxia (LTIH), one of the hallmarks of OSAS, could mediate ED. The objective of this study was to test the hypothesis that increased nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity contributes to ED in rat responses to LTIH. Healthy male Sprague‐Dawley rats were randomly distributed into 4 groups: a LTIH group, an apocynin (a selective NADPH oxidase inhibitor)‐treated LTIH group, a sham LTIH group, and an apocynin‐treated sham group. Erectile function was examined by measuring the mean arterial blood pressure (MAP) and intracavernosal pressure (ICP) on electrical stimulation of the cavernous nerve. Real‐time quantitative polymerase chain reaction and Western blot were used to examine mRNA and protein expression of NADPH oxidase subunit in corpus cavernosa (CC). The level of malondialdehyde and superoxide dismutase were detected by colorimetry. Nitric oxide synthase (NOS) isoforms in CC were also investigated. LTIH markedly attenuated the erectile responses (ICP/MAP), and these were partially prevented by apocynin treatment. Promoted oxidative stress–associated NADPH oxidase subunit activation was found in CC from LTIH rats. Decreased expression and activity of constitutive NOS (cNOS), including endothelial NOS and neuronal NOS, associated with enhanced inducible NOS (iNOS) expression and activity were observed in LTIH rats. Apocynin prevented the decrease in cNOS activity and inhibited iNOS expression and activity in LTIH rats. These results indicate that NADPH oxidase activation plays an important role in the pathogenesis of LTIH‐mediated ED.
Effects of Castration and Late Hormonal Replacement in the Structure of Rat Corpora Cavernosa
Authors: Miranda Alexandre F. , Gallo Carla B. M. , de Souza Diogo B. , Costa Waldemar S. , Sampaio Francisco J. B.
Published: November 2012

Abstract: The objective of the study was to evaluate, through quantitative methods, the structural alterations in the corpora cavernosa of rats submitted to orchiectomy as well as the role of late hormone replacement in overturning the possible structural alterations. Twenty‐five male rats were assigned into 5 groups with 5 animals each and treated as follows: ORCHIEC‐1 = submitted to orchiectomy and sacrificed after 1 month; C‐1 = control group sacrificed after 1 month; ORCHIEC‐2 = submitted to orchiectomy and sacrificed after 2 months; C‐2 = control group sacrificed after 2 months; and T / submitted to orchiectomy, underwent testosterone replacement with testosterone undecanoate (100 mg/kg) after 1 month, and sacrificed after 1 month of hormonal replacement. Smooth muscle, collagen, and elastic system fibers of penile corpora cavernosa were quantified. There was a significant decrease in the absolute values of smooth muscle, sinusoidal space, and total area of corpora cavernosa after 2 months in the castrated group when compared with controls. Overall, regarding density, no significant differences were observed among the groups. The hormonal replacement with testosterone was able to reverse the alterations observed. The method used for this research allowed demonstrating that absolute values are reliable to quantify the structural alterations of corpora cavernosa structures. The results suggest that hormonal replacement, even when instituted at a late stage, is effective in reversing the corpora cavernosa's structural alterations produced by castration.
Numerical investigation of fluid flow and heat transfer characteristics on the aerodynamics of ventilated disc brake rotor using CFD
Authors: Raj Karuppa , Ramsai R. , Mathew J. , Soniya G.
Published: November 2012

Ventilated brake discs are used in high speed vehicles. The brake disc is an
important component in the braking system which is expected to withstand and
dissipate the heat generated during the braking event. In the present work,
an attempt is made to study the effect of vane-shape on the flow-field and
heat transfer characteristics for different configurations of vanes and at
different speeds numerically. Three types of rotor configurations circular
pillared, modified taper radial and diamond pillar vanes were considered for
the numerical analysis. A rotor segment of 20? was considered for the
numerical analysis due to its rotational symmetry. The pre processing is
carried out with the help of ICEM-CFD and analysis is carried out using
ANSYS CFX 12.1. The three dimensional flow through the brake rotor vanes has
been simulated by solving the appropriate governing equations viz.
conservation of mass, momentum and energy using the commercial CFD tool,
ANSYS CFX 12. The predicted results have been validated with the results
available in the literature. Circular pillar rotor vanes are found to have
more uniform pressure and velocity distribution which results in more
uniform temperature drop around the vanes. The effect of number and diameter
of vanes in the circular pillared rotor is studied and the geometry is
optimized for better mass flow and heat dissipation characteristics.
Thermal impedance estimations by semi-derivatives and semi-integrals: 1-D semi-infinite cases
Authors: Hristov Jordan , El Ganaoui
Published: November 2012

Simple 1-D semi-infinite heat conduction problems enable to demonstrate the
potential of the fractional calculus in determination of transient thermal
impedances under various boundary conditions imposed at the interface (x=0).
The approach is purely analytic and very effective because it uses only
simple semi-derivatives (half-time) and semi-integrals and avoids
development of entire domain solutions. 0x=
Clinical Evaluation of a Personalized Artificial Pancreas
Authors: Dassau Eyal , Zisser Howard , Harvey Rebecca A. , Percival Matthew W. , Grosman Benyamin , Bevier Wendy , Atlas Eran , Miller Shahar , Nimri Revital , Jovanovič Lois , Doyle Francis J.
Published: November 2012

OBJECTIVE

An artificial pancreas (AP) that automatically regulates blood glucose would greatly improve the lives of individuals with diabetes. Such a device would prevent hypo- and hyperglycemia along with associated long- and short-term complications as well as ease some of the day-to-day burden of frequent blood glucose measurements and insulin administration.

RESEARCH DESIGN AND METHODS

We conducted a pilot clinical trial evaluating an individualized, fully automated AP using commercial devices. Two trials (n = 22, nsubjects = 17) were conducted using a multiparametric formulation of model predictive control and an insulin-on-board algorithm such that the control algorithm, or “brain,” can be embedded on a chip as part of a future mobile device. The protocol evaluated the control algorithm for three main challenges: 1) normalizing glycemia from various initial glucose levels, 2) maintaining euglycemia, and 3) overcoming an unannounced meal of 30 ± 5 g carbohydrates.

RESULTS

Initial glucose values ranged from 84–251 mg/dL. Blood glucose was kept in the near-normal range (80–180 mg/dL) for an average of 70% of the trial time. The low and high blood glucose indices were 0.34 and 5.1, respectively.

CONCLUSIONS

These encouraging short-term results reveal the ability of a control algorithm tailored to an individual’s glucose characteristics to successfully regulate glycemia, even when faced with unannounced meals or initial hyperglycemia. To our knowledge, this represents the first truly fully automated multiparametric model predictive control algorithm with insulin-on-board that does not rely on user intervention to regulate blood glucose in individuals with type 1 diabetes.
Probability of Capacity Enhancement and Disruption for Freeway Ramp Controls
Authors: Tian Zong Z. , Wu Ning
Published: November 2012

Models based on gap-acceptance and queuing theory are proposed to model the effect of ramp controls on freeway operations. The models were developed for three types of patterns in ramp control and traffic flow: the uniform arrival with ramp metering, the random arrival without ramp metering, and the platoon arrival without ramp metering but with an upstream signalized intersection. From the theoretical point of view, the models were applied to address freeway ramp metering thresholds and the corresponding disruption probability. Studies have shown that ramp metering has been effective in reducing vehicle delays only when the rate of freeway traffic flow has reached a certain level of flow threshold. When freeway traffic is low, there are enough gaps in the freeway flow to accommodate the ramp flow, even when ramp traffic enters the freeway in platoons. The presented models accounted for the effect of platoon size that resulted from the three ramp controls and arrival flow patterns. Study results clearly indicate that more significant disruption on freeway operations occurs as a result of large platoon arrivals caused by an upstream traffic signal, than as a result of traffic that arrives randomly or uniformly. The models were also applied to provide quantitative assessments from the perspectives of freeway capacity. The results indicate that ramp metering produces increased freeway capacity and decreased disruption probability.
Managed Motorways
Authors: van Vuren Tom , Baker Jo , Ogawa Jennifer , Cooke David , Unwin Paul
Published: November 2012

Managed motorways (formerly known as active traffic management) aim to address traffic congestion and improve journey time reliability with a set of advanced applications of intelligent transport systems to maximize available road capacity. An important feature of managed motorways is the use of hard shoulder running together with variable mandatory speed limits during periods of congestion. Managed motorways were first trialed in the Netherlands and have been in operation in the United Kingdom since 2006. This paper presents the monitoring results of the introduction of managed motorways around Birmingham in the United Kingdom and also describes modeling methods that were used to generalize the findings. Managed motorways around Birmingham have been so effective that they are to be introduced by the UK Highways Agency across the wider network. This paper summarizes the findings of 5 years of monitoring and modeling and refers to the wider set of papers and reports in the public domain for deeper analysis. The paper describes the rigor in monitoring before and after data and in the modeling support for the assessment of outcomes of this transportation investment decision; these outcomes include a reference to the relationship with the economic development in the area. Discussion includes results from a before and after data analysis exercise, the contribution by microsimulation modeling, and findings from an extensive consultation exercise with users of the scheme. The wider economic impacts of investment in managed motorways are examined. The intention is to produce guidance for those transportation organizations that are considering the implementation of managed motorways elsewhere in the world, in particular in the United States.
Response Time of Highway Traffic Accidents in Abu Dhabi
Authors: Al Kaabi Abdulla , Dissanayake Dilum , Bird Roger
Published: November 2012

Traffic incidents generate many adverse impacts, especially as far as traffic congestion, air pollution, fuel consumption, and secondary crashes are concerned. Therefore traffic incident responders and operators must know how to improve the efficiency of traffic incident management. This paper presents the results of an investigation into the effects of traffic accident characteristics on accident response time, with fully parametric hazard-based duration models with emphasis on the accelerated failure time metric. Accident characteristics and response times were obtained from Abu Dhabi, the capital of the United Arab Emirates. For an investigation into the factors affecting response time, data were retrieved from the Federal Traffic Statistics System and the Abu Dhabi Highway Collision Investigation Branch (AHCIB) for the period January to December 2009. For the purpose of this study, “response time” was defined as the length of time between the first report of the incident being received by AHCIB and the time that the first collision investigator arrived at the scene. After a goodness-of-fit test was conducted, a Weibull distribution with frailty was used. Results showed that various accident characteristics, including day of the week, month of the year, accident type, and location of the accident, affected response time. These results highlighted some weaknesses in the current highway accident management practices in Abu Dhabi, particularly the impact of lack of resources on the ability of the AHCIB to respond to an accident immediately upon notification of its occurrence. This paper suggests some measures designed to mitigate response problems.
Integrated Corridor Management for Urban Transport
Authors: Zimmerman Sam , Dahdah Said , Wang Wei
Published: November 2012

In developing cities, increases in travel resulting from exponential population, employment, income, and motorization growth can be accommodated only if the efficiency and effectiveness of all transport system resources are maximized. The developed cities of Europe and North America have already demonstrated that comprehensive packages of traffic demand and roadway supply management, public and non-motorized transport priority, and safety improvements integrated on a corridor basis are needed. The objective of this approach, known as integrated corridor management (ICM), is to use roadway infrastructure and public transport supply to move the most people safely, quickly, and reliably with minimum environmental effects. Examples of where ICM has worked effectively include the quality bus corridors of Dublin, Ireland, Manchester, United Kingdom, and London; Seoul's complete makeover of its bus system in South Korea; and New York City's selected bus services. The World Bank is involved in a substantial and growing number of cities in Asia where ICM is being introduced in places where resources are more constrained than in typical developed cities. After the basic approach and its applications in London and New York are described, the methodology being used by World Bank client cities to plan and implement ICM is discussed. Process details on corridor selection and problem diagnosis, identification and evaluation of improvement options, and implementation are described. Finally, a case study of the recent World Bank–funded urban transport project in Wuhan, the capital of Hubei Province, China, is provided to demonstrate the feasibility and ease of applying this methodology in China and elsewhere in the developing world.
Traffic Impacts of Variable Pricing on the San Francisco–Oakland Bay Bridge, California
Authors: Cervero Robert
Published: November 2012

The raising of bridge tolls in the peak period on the San Francisco-Oakland Bay Bridge in California in mid-2010 provides a rare opportunity to assess traffic impacts. Carpoolers who previously traveled for free during peak hours were charged an electronic toll under this variable pricing scheme. On the basis of 29 months of time series data, the introduction of carpool charges had a stronger impact on traffic volumes than did peak period pricing of regular traffic. The estimated short-term elasticity of about −0.30 suggests significant numbers of peak hour carpoolers did not travel, switched routes, shifted to public transit, or opted to drive alone. More than half the loss in carpool traffic was estimated to be attributable to the toll increase, a far stronger influence than factors such as rising gasoline prices and unemployment. The estimated elasticity of regular traffic in response to variable pricing was −0.23, an indication that peak period motorists were fairly insensitive to pricing and a reflection of the nondiscretionary nature of many peak hour journeys. It will be important to track trends over time to gain insights into the longer term sensitivity of motorists to variable pricing on natural corridors such as the San Francisco–Oakland Bay Bridge.
Performance Evaluation of I-394 MnPASS Express Lanes in Minnesota
Authors: Buckeye Kenneth R.
Published: November 2012

In 2005 the Minnesota Department of Transportation (DOT) implemented the state's first optional toll lane project, the I-394 MnPASS Express Lanes. Located in the western half of the Minneapolis–Saint Paul metropolitan area, the MnPASS Express Lanes project converted underperforming high-occupancy vehicle lanes on Interstate 394 into high-occupancy toll lanes that allowed solo drivers the opportunity to pay an electronic fee to bypass congestion. After more than 5 years of operational experience, Minnesota DOT conducted an evaluation to determine whether MnPASS Express Lanes have met performance expectations and goals. The results of this analysis indicate that the lanes are performing efficiently, are continuing to ensure free-flow speeds for all users, and are enhancing vehicle and person throughput. In addition, the lanes generate sufficient revenue to cover operational costs. A recent survey indicates that MnPASS Express Lanes are providing users with value for their money in time savings and overall customer satisfaction.
Quantifying Cross-Weave Impact on Capacity Reduction for Freeway Facilities with Managed Lanes
Authors: Liu Xiaoyue Cathy , Wang Yinhai , Schroeder Bastian J. , Rouphail Nagui M.
Published: November 2012

With the increasing concerns about environmental effects and the sustainability of roadway capacity expansion, transportation agencies are seeking alternative solutions to mitigate congestion. Managed lanes (MLs) promote person throughput on freeways and manage congestion through improving efficiency. The ML concept therefore has been gaining popularity in past decades. However, the lack of guidance on evaluating the performance of the ML facility poses challenges for agencies wanting to design and implement the strategy effectively. Many MLs are designed to be left-lane concurrent; vehicles entering the freeway from general purpose (GP) lane on-ramps need to cross weave over multiple GP lanes to access the ML. These weaving vehicles will have a negative effect on the operating performance of the parallel GP lanes. This paper investigates this cross-weaving effect as a function of different roadway geometric configurations as well as traffic conditions. A microscopic simulation model was built and calibrated on the basis of video data collected along I-635 in Dallas, Texas. Multiple scenarios were tested to explore the effect of the following parameters: number of GP lanes, cross-weave demand, and cross-weaving length. A set of capacity adjustment factors was determined to account for this effect as a function of those parameters. Results showed that the capacity-reducing effect was higher with a reduction in cross-weaving length, an increase in the number of GP lanes, or a rise in cross-weave demand volumes. The results are important in evaluating the operational performance of freeway segments in the presence of concurrent GP lanes and MLs in a Highway Capacity Manual context.
2D modelling of induced polarization data with anisotropic complex conductivities
Authors: Kenkel Johannes , Hördt Andreas , Kemna Andreas
Published: November 2012

Induced polarization data recorded at the field scale are usually processed using techniques based on isotropy. We study the effect of anisotropic complex conductivities in the frequency domain, with a particular emphasis on the polarization properties (i.e., phase angles). We consider anisotropy to be caused by a thin layering of isotropic media. Based on this, we derive corresponding mixing laws for the phase angles parallel and perpendicular to the layering and show that in cases of anisotropic layering, phase angles can only exist if the complex conductivity magnitudes are also anisotropic. We modified an existing isotropic finite‐element forward modelling code to support anisotropic complex conductivities. Based on an isotropic 2D inversion of a synthetic data set generated for an anisotropic model, we show that ignoring anisotropy may lead to artefacts and poor model recovery. Finally, we investigate a field data set recorded over a fault system in Germany, where anisotropic conductivities are expected. The isotropic 2D inversion of this data set yields a complex image that is difficult to interpret. We suggest an alternative interpretation based on trial‐and‐error forward modelling with anisotropic complex conductivities, using geological a priori information to constrain the model. The obtained model has a much simpler structure, consistent with the anticipated geology but yet is able to explain the measured data.
The Effects of Spatial Resolution in Turbulent Boundary Layers with Pressure Gradients
Authors: Harun Zambri , Isa Mohamad Dali , Rasani Mohammad Rasidi , Abdullah Shahrir
Published: November 2012

Single normal hot-wire measurements of the streamwise component of velocity were taken in boundary layer flows subjected to pressure gradients at matched friction Reynolds numbers Reτ ≈ 3000. To evaluate spatial resolution effects, the sensor lengths are varied in both adverse pressure gradient (APG) and favorable pressure gradient (FPG). A control boundary layer flow in zero pressure gradient ZPG is also presented. It is shown here that, when the sensor length is maintained a constant value, in a contant Reynolds number, the near-wall peak increases with (adverse) pressure gradient. Both increased contributions of the small- and especially large-scale features are attributed to the increased broadband turbulence intensities. The two-mode increase, one centreing in the near-wall region and the other one in the outer region, makes spatial resolution studies in boundary layer flow more complicated. The increased large-scale features in the near-wall region of an APG flow is similar to large-scales increase due to Reynolds number in ZPG flow. Additionally, there is also an increase of the small-scales in the near-wall region when the boundary layer is exposed to adverse pressure gradient (while the Reynolds number is constant). In order to collapse the near-wall peaks for APG, ZPG and FPG flows, the APG flow has to use the longest sensor and conversely, the FPG has to use the shortest sensor. This study recommends that the empirical prediction by Huthins et. al. (2009) to be reevaluated if pressure gradient flows were to be considered such that the magnitude of the near-wall peak is also a function of the adverse pressure gradient parameter.
Damage Identification and Classification in CFRP Laminates – A SEM Based Study
Authors: Sultan Mohamed Thariq Hameed , Yidris Noorfaizal , Mustapha Faizal , Rafie Azmin Shakrine M. , Majid Dayang Laila
Published: November 2012

There are two main factors that need to be considered as important parameters that affect the response of a structure: kinetic energy (E=1/2mv^2 ) and potential energy (E=mgh). For instance, if one has a large mass but with lower height, the amount of damage produced on the structure may not be the same as if one has a smaller mass with a higher dropping height although the potential energies will be the same. Therefore, before performing tests on the structures, the selection for the appropriate test apparatus and test procedures must be made carefully to ensure that the test conditions are similar to the actual impact conditions. In this present work, a study was conducted to fully understand the damage progression and growth, not only should the impacted surface be evaluated, but also the cross sectional defects on the impacted area must be accurately identified and examined. In this current work, the impacted test specimens will be observed at different magnifications to distinguish the types of failure mechanisms using Scanning Electron Microscopy (SEM). To perform this, the impacted specimens will be examined by two different approaches: surface defects and cross-sectional defects. This allows the failure mechanism to be observed more precisely.
Generic Modeling and Parametric Study of Flapping Wing Micro-Air-Vehicle
Authors: Djojodihardjo Harijono , Ramli Alif Syamim Syazwan , Wiriadidjaja Surjatin
Published: November 2012

The present work is focused on the unsteady aerodynamics of bio-inspired flapping wing to produce lift and thrust for hovering and forward flight. A generic approach is followed to understand and mimic the mechanism and kinematics of ornithopter by considering the motion of a three-dimensional rigid thin wing in flapping and pitching motion, using strip theory and two-dimensional unsteady aerodynamics for idealized wing in pitching and flapping oscillations with phase lag. Parametric study is carried out to obtain the lift, drag, and thrust characteristics within a cycle for assessing the plausibility of the aerodynamic model, and for the synthesis of a Flapping Wing MAV model with simplified mechanism. Other important parameters such as flapping frequency and wing geometry are considered. Results are assessed in comparison with the existing theoretical results.
Damage Classification in CFRP Laminates Using Principal Component Analysis (PCA) Approach
Authors: Sultan Mohamed Thariq Hameed , Rafie Azmin Shakrine M. , Yidris Noorfaizal , Mustapha Faizal , Majid Dayang Laila
Published: November 2012

Signal processing is an important element used for identifying damage in any SHM-related application. The method here is used to extract features from the use of different types of sensors, of which there are many. The responses from the sensors are also interpreted to classify the location and severity of the damage. This paper describes the signal processing approaches used for detecting the impact locations and monitoring the responses of impact damage. Further explanations are also given on the most widely-used software tools for damage detection and identification implemented throughout this research work. A brief introduction to these signal processing tools, together with some previous work related to impact damage detection, are presented and discussed in this paper.
The Behaviour of Fibre-Metal Laminates under High Velocity Impact Loading with Different Stacking Sequences of Al Alloy
Authors: Ramadhan A.A. , Talib Abdul Rahim Abu , Rafie Azmin Shakrine Mohd , Zahari R.
Published: November 2012

The high velocity impact response of composite laminated plates has been experimentally investigated using a nitrogen gas gun. Tests were undertaken on fibre-metal laminate (FML) structures based on Kevlar-29 fiber/epoxy-Alumina resin with different stacking sequences of 6061-T6 Al plates. Impact testing was conducted using a cylindrical shape of 7.62 mm diameter steel projectile at 400m/s velocity, which was investigated to achieve complete perforation of the target. The numerical parametric study of ballistic impacts caused by similar conditions in experimental work is undertaken to predict the ballistic limit velocity, energy absorbed by the target, and comparisons between simulations by using ANSYS AUTODYN 3D v.12.1 software and experimental work to study the effects of the shape of the projectile with different (4, 8, 12, 16 and 20mm) thicknesses on the ballistic limit velocity. While only one thickness was used with 24mm of back stacking sequence, it was not penetrated. The sequence of the Al plate position (front, middle and back) inside laminate plates of the composite specimen was also studied. The Al back stacking sequence plate for the overall results obtained was the optimum structure to resist the impact loading. The simulation results obtained of the residual velocity hereby are in good agreement with the experimental results with an average error of 1.8%. The energy absorption was obtained with 7.3% and 2.7% of the back to front and back to middle of the Al stacking sequence respectively. Hence, the back Al stacking sequence is considered the optimum position for resisting the impact loading. The data showed that these novel sandwich structures exhibit excellent energy-absorbing characteristics under high-velocity impact loading conditions. Hence, it is considered suitable for aerospace applications.
Conceptual Design of Solar Powered Unmanned Arial Vehicle
Authors: Abu-Hamdeh Nidal H. , Alnefaie Khaled A. , Al-Hajjaj Majed K.
Published: November 2012

The solar-powered aircraft represents a major step forward in environmentally friendly vehicle technology. An unmanned aircraft vehicle (UAV) was designed to fly for 24 hours continuously to achieve surveillance at low altitude. It is a lightweight, solar-powered, remotely piloted flying wing aircraft that is demonstrating the technology of applying solar power for long-duration and low-altitude flight. Several programs and codes were used in the designing process of the UAV and generating its layout. A MATLAB computer programming code was written to optimize on various values of aspect ratio (AR) and wingspan (b) after setting the mission requirements and estimating the technological parameters. A program called Java Foil was used to calculate the lift. Another program called RDS was used to obtain the final layout of the aircraft. The great benefit is that the design is general enough to be applied to different values of aspect ratio and wingspan. Moreover, the analytical form of the method allows identifying clear some general principles like the optimization on various values of aspect ratio and wingspan, and the calculation of the lift.
Stability Analysis of a Light Aircraft Configuration Using Computational Fluid Dynamics
Authors: Mahdi Mohammed , Elhassan Yasser A.
Published: November 2012

This work aims to simulate and study the flow field around SAFAT-01 aircraft using numerical solution based on solving Reynolds Averaged Navier-Stokes equations coupled with K-ω SST turbulent model. The aerodynamics behavior of SAFAT-01 aircraft developed at SAFAT aviation complex were calculated at different angles of attack and side slip angles. The x,y and z forces and moments were calculated at flight speed 50m/s and at sea level condition. Lift and drag curves for different angles of attack were plotted. The maximum lift coefficient for SAFAT-01 was 1.67 which occurred at angle of attack 16° and Maximum lift to drag ratio (L/D) was 14 which occurred at α=3°, and the zero lift drag coefficient was 0.0342. Also the yawing moment coefficient was plotted for different side slip angles as well as rolling moment. The longitudinal stability derivatives with respect to angle of attack, speed variation (u), rate of pitch (q) and time rate of change of angle of attack were calculated using obtained CFD results. Concerning lateral stability only side slips derivatives were calculated. To validate this numerical simulation USAF Digital DATCOM is used to analyze this aircraft; a comparison between predicted results for this aircraft and Digital DATCOM indicated that this numerical simulation has high ability for predicting the aerodynamics characteristics.
Parametric Study of Ground-Track Based Performance Measure Requirements for the Optimization of Near Earth Twin-Spacecrafts Trajectory
Authors: Djojodihardjo Harijono , Gunter A. Aq'Grabin A. , Varatharajoo Renuganth
Published: November 2012

Parametric optimization study is carried out on performance measure for assessing the benefits of relevant ground-track parameters and Instantaneous Overlap Area (IOA) in near earth and near-equatorial twin-satellite formation flying to explore its potential as space platform oriented towards Tropical Resources and Environment Monitoring mission. The present study also emphasizes two aspects: the dynamics of relative motion of multiple spacecrafts and the desirable ground tracks such missions. Relative motion dynamics incorporating Clohessy-Wiltshire Equation for circular orbits is used as a reference. The performance metric is synthesized as a tradeoff between exact definition and intuitive judgment.
Single Parameter-Based Neural Networks Prediction of TEC
Authors: Jayapal Vikneswary , Ahmad Faizal Mohd Zain
Published: November 2012

Total electron content (TEC) is a highly non-linear ionospheric parameter that is strongly affected by changes in the solar activity. Reliability of space-based systems is affected by TEC and hence requires the development of a good model to nowcast and forecast its variability. Therefore, the aim of this paper is to present a Neural Networks (NN) model to predict the TEC variability. Slant TEC (sTEC) from the GPS Ionospheric Scintillation and TEC Monitor (GISTM) receiver is calculated and converted to vertical TEC (vTEC) based on the Single Layer Model (SLM). As a preliminary study, only one variable is considered as an input parameter for the NN, which is the hourly vTEC values and this is used to train the network with feed forward back propagation (BP) algorithm. The data set is the observed TEC for April and May 2005. Absolute maximum error and root mean square error (RMSE) are then calculated for each trained NN to evaluate the performance of the model. Analysis of the results reveals that, on average, the NN model is capable to predict TEC values but however extended input data set is needed to improve the generalization capability and reliability of the model. The highest absolute maximum error is 17 TECU and the smallest absolute maximum error is 6 TECU. The RMSE values for May 27 to May 30 are 1 TECU, 4 TECU, 5 TECU and 1 TECU, respectively.
Comparative Study on Aircraft Landing Instruments: Accuracies and Limitations
Authors: Salih Ahmad Abbas Al-Ameen , Zhahir Amzari , Ariff Omar Kassim
Published: November 2012

A normal aircraft flight includes taxi, takeoff, climb, cruise, descent, precision approach and finally landing. This study focuses on landing where the aircraft returns to the ground safely. In low visibility conditions, when pilots are unable to see the runway, the aircraft can always be diverted to another airport. However, low visibility can also affect all airports in the vicinity, forcing aircrafts to land in low visibility conditions depending on Instrument Flight Rules (IFR). Many countries have employed the landing systems because of inaccuracy, unreliability and dependency of Visual Flight Rules (VFR). In this paper, aircraft landing systems accuracies and limitations will be studied and compared for the purpose of assessing the best possible system currently available that can be achieved and implemented.
Subsonic Wind Tunnels in Malaysia: A Review
Authors: Wiriadidjaja Surjatin , Hasim Fadilah , Mansor Shuhaimi , Asrar Waqar , Rafie Azmin Shakrine Mohd , Abdullah Ermira Junita
Published: November 2012

In Malaysia, there exist wind tunnels operated by several universities and organizations. Most of them are actively used for a variety of experimental works that are needed by uncounted educational curricula and aerodynamics related researches. Lately, wind tunnels have even become increasingly accepted as one of common engineering tools in solving of unexpected and abundant wind engineering problems that are continually facing automotive industries, oil and gas companies, as well as governmental agencies and ministries. This paper is meant to present an overview of the existing wind tunnels, accompanied with information on some important technical data, and added, to a lesser extent, with complementary information about backgrounds and design philosophies. The emphasis is, however, given only to those with test section size of 1.0 square meter or larger. From the general point of view, some information about testing capabilities and trends in wind tunnel technology is also presented.
Tilt Response of Multi-Storey Building of Different Types due to Progressive Collapse of the Adjacent Underground Structure under Internal Blast Loading
Authors: Tian Li , Song Hai Xian
Published: November 2012

This paper numerically investigates the tilt response of multi-storey buildings due to progressive collapse of the adjacent underground structure under internal blast loading. The software LS-DYNA is utilized to establish a three-dimensional coupled model composed of the underground structure, the soil around and the adjacent above-ground structure. In order to reduce the computational cost, an efficient computational method, Three-Stage Simulation Method (TSSM), is put forward. Three different methods, Alternative Path Load Method (APLM), Direct Simulation Method (DSM) and TSSM, are used to analyze the same model which illustrates the correctness of the model and the proposed method. By comparing tilt response of the above-ground structure of different types due to progressive collapse of underground structure under its internal blast loading, it is found that the tilt response of the above-ground structure of different types is related to the foundation of the structure. For example, compared with the frame structure with basement, the frame-shear wall structure with basement can prevent structure from great tilt response. However, the tilt response of the frame-shear wall structure with raft basis is larger than that of the frame.
Precipitation Characteristics of CaCO3 Scaling on Stainless Steel in Cooling Tower Condition
Authors: Sheng Jian , Zhang Hua
Published: November 2012

Stainless steel 304 and 316 (ss304 and ss316) are widely used in heat exchangers, and the precipitation characteristics of CaCO3 is the first step to research anti-fouling technology. CaCO3 scaling precipitated on coupons from 1.0mmol/l CaCO3 solution at 35°C. By weighing the coupons before and after static reaction experiments to get the mass of scaling and the morphology was taken by Scanning Electron Microscope (SEM). The results show that at the same condition there is more fouling on ss304 than ss316. Higher pH not only promotes square aragonite and calcite and square aragonite gradually recrystallize to calcite but also makes both homogeneous and heterogeneous nucleation rate increasing, and the former increases more, so the fouling mass is bigger at lower pH than higher pH; fouling grows at the place with higher surface energy first and then extend to surrounding place, and when the number increases and crystals grow big and connect each other to form fouling layer.
A New Method for Dynamic p-y Curves of Pile-Cap Structure in Layered Soil
Authors: Li Yu Run , Liang Yan , Wei Xing , Wang Yun Long
Published: November 2012

Lateral dynamic response of pile foundation in liquefiable soil has been one of the focal problems of the geotechnical engineering field and varieties of test methods are put forward by experts and scholars. In the dissertation, a shaking table test is based on and a new calculation method is involved too. It’s the first time that using Fiber Prague Grating (FBG) technology in the method of study on lateral dynamic response of pile foundation in liquefiable soil. Experimental results indicate that calculation by method of FBG is more accurate than that by acceleration integral method. Data processing shows that p-y curve of pile foundation in liquefiable soil can be better to indicate the actual dynamic constitutive relation, and it establishes the theoretical basis of experimental study and engineer application of pile foundation in liquefiable soil
Study on Determining Safety-Monitoring Index for Concrete Dam Based on Cloud Model
Authors: Qin Dong , Zheng Xue Qin , Wang Song Lin
Published: November 2012

The paper, based on analyzing original monitoring data, employs forward and backward cloud algorithm in studying determining safety-monitoring index for concrete dam ,which integrates randomness and fuzziness into of qualitative concept of digital features. By means of above monitoring data, its digital characteristics can be easily transformed to the “quantitative-qualitative- quantitative” change. The final generated quantitative value constitutes the cloud diagram where each droplet demonstrates the characterization of raw monitoring data. At the same time, it also shows the randomness and fuzziness of monitored value. we can study out the safety monitoring indexes according to different remarkable levels by using the probability density function and deterministic function which completed by cloud algorithm. In the end, it is obtained with practice that this method is more suitable and reliability.
Application Research of the Dynamic Compaction Method with Precipitation in Foundation Treatment Dredger Fill
Authors: Xuan Fei , Peng Chao Qun , Jia Yan
Published: November 2012

In the view of the actual project, this paper analyses the credit problems of the foundation treatment, from the three aspects of the location, the shallow blow fill and the pile’s negative firctio- n. Then this paper especially studies the field testing scheme about the dynamic compaction method with precipitation, based on the analysis of the percussive compaction method with precipitation, the dynamic compaction method with precipitation and packless vibroflotation method. Meanwhile, the operated steps and the attention of the construction have been enucleated.
Study of Vibration Characteristics of Cantilever Rectangular Plate with Side Crack
Authors: Chen Li Hua , Sun Yue , Zhang Wei
Published: November 2012

In this paper, the vibration characteristics of the cantilever rectangular plate with side crack are studied in the way of analysis, which including natural frequency and mode shape. The influences of different parameters of crack, such as the locations and lengths of crack, to the vibration characteristics of the cantilever rectangular plate are investigated. The modal function of the crack plate consists two parts, which are (1) the modal function of intact cantilever rectangular plate from beam functions combination method and (2) corner functions presenting the discontinuity of displacement and slope along the crack. The natural frequencies and modal shapes can be obtained when taking the modal function into the method of Ritz. At last, the effects of the crack location and crack length on the vibration characteristics are investigated, and it could provide the theoretical basis for engineering application and the relevant study.