bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Patient-Reported Outcomes in Oncology: A Longitudinal Analysis of Patient-Physician Communication
Authors: Takeuchi Elena E. , Keding Ada , Awad Noha , Hofmann Ursula , Campbell Lyndsay J. , Selby Peter J. , Brown Julia M. , Velikova Galina
Published: June 2011

Purpose

Regularly collecting patient-reported outcomes (PROs) of health-related quality of life with feedback to oncologists may assist in eliciting and monitoring patients' problems during cancer treatment. This study examined how PRO feedback had an impact on patient-physician communication over time to gain a better understanding of how it may influence patient care.

Patients and Methods

Exploratory analyses were performed on a data set from a previous study. Patients were randomly assigned to intervention (regular completion of European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 and Hospital Anxiety and Depression Scale with feedback to oncologists), attention-control (completion of same questionnaires without feedback), and control (standard care) arms. The content of consultation audio recordings between 28 oncologists and 198 patients over four consecutive visits (792 consultations) was analyzed. Mixed-effects models and multivariate regressions were used to examine the longitudinal impact of the intervention on patient-physician communication, dynamics of patient-physician interaction, and the association between PROs and the content of clinic discussion.

Results

Patients in the intervention arm discussed more symptoms over time compared with patients in the attention-control (P = .008) and control (P = .04) arms. No study arm effect was observed for function discussions. Discussion topics were predominantly raised by patients/relatives, regardless of arm allocation. Clinic discussions were associated with severity of patient-reported symptoms but not with patient-reported functional concerns.

Conclusion

A positive longitudinal impact of the intervention on symptom discussion was observed, but not for function discussion, suggesting that potentially serious problems may remain unaddressed. Training oncologists in responding to patient-reported functional concerns may increase the impact of this intervention.
Phase II, Open-Label, Single-Arm Trial of Imatinib Mesylate in Patients With Metastatic Melanoma Harboring c-Kit Mutation or Amplification
Authors: Guo Jun , Si Lu , Kong Yan , Flaherty Keith T. , Xu Xiaowei , Zhu Yanyan , Corless Christopher L. , Li Li , Li Haifu , Sheng Xinan , Cui Chuanliang , Chi Zhihong , Li Siming , Han Mei , Mao Lili , Lin Xuede , Du Nan , Zhang Xiaoshi , Li Junling , Wang Baocheng , Qin Shukui
Published: June 2011

Purpose

Melanomas harbor aberrations in the c-Kit gene. We tested the efficiency of the tyrosine kinase inhibitor imatinib in selected patients with metastatic melanoma harboring c-Kit mutations or amplifications.

Patients and Methods

Forty-three patients with metastatic melanoma harboring c-Kit aberrations were enrolled on this phase II trial. Each patient received a continuous dose of imatinib 400 mg/d unless intolerable toxicities or disease progression occurred. Fifteen patients who experienced progression of disease were allowed to escalate the dose to 800 mg/d.

Results

Forty-three patients were eligible for evaluation, and the median follow-up time was 12.0 months. The median progression-free survival (PFS) was 3.5 months, and the 6-month PFS rate was 36.6%. Rate of total disease control was 53.5%: 10 patients (23.3%; 95% CI, 10.2% to 36.4%) and 13 patients (30.2%; 95% CI, 16.0% to 44.4%) achieved partial response (PR) and stable disease (SD), respectively. Eighteen patients (41.9%) demonstrated regression of tumor mass. Notably, nine of the 10 PRs were observed in patients with mutations in exons 11 or 13. The 1-year overall survival (OS) rate was 51.0%. The median PFS and OS times for patients who had PR or SD versus disease progression were 9.0 months versus 1.5 months (P < .001) and 15.0 months versus 9.0 months (P = .036), respectively. Imatinib 400 mg/d was well tolerated, and only one of the 15 patients who received dose escalation to 800 mg/d achieved SD.

Conclusion

Imatinib demonstrated significant activity in patients with metastatic melanoma harboring genetic c-Kit aberrations, with an overall response rate of 23.3%. Escalation to 800 mg/d could not restore disease control.
Exercise Behavior, Functional Capacity, and Survival in Adults With Malignant Recurrent Glioma
Authors: Ruden Emily , Reardon David A. , Coan April D. , Herndon James E. , Hornsby Whitney E. , West Miranda , Fels Diane R. , Desjardins Annick , Vredenburgh James J. , Waner Emily , Friedman Allan H. , Friedman Henry S. , Peters Katherine B. , Jones Lee W.
Published: June 2011

Purpose

Identifying strong markers of prognosis are critical to optimize treatment and survival outcomes in patients with malignant recurrent glioma. We investigated the prognostic significance of exercise behavior and functional capacity in this population.

Patients and Methods

Using a prospective design, 243 patients with WHO grades 3 to 4 recurrent malignant glioma and Karnofsky performance status (KPS) ≥ 70 completed a self-administered questionnaire that assessed exercise behavior and performed a 6-minute walk test (6MWT) to assess functional capacity. Cox proportional models were used to estimate the risk of all-cause mortality according to 6MWT distance (6MWD; < 390 meters, 390-489 meters, > 489 meters) and exercise behavior (metabolic equivalent [MET] –h/wk) adjusted for KPS and other important clinical factors.

Results

Median follow-up was 27.43 months. During this period, 149 deaths were recorded (61% of the total sample). Exercise behavior was an independent predictor of survival (P = .0081). Median survival was 13.03 months for patients reporting < 9 MET-h/wk relative to 21.84 months for those reporting ≥ 9 MET-h/wk. Exercise behavior added incremental prognostic value beyond that provided by KPS, age, sex, grade, and number of prior progressions (P < .001). Compared with patients reporting < 9 MET-h/wk, the adjusted hazard ratio for mortality was 0.64 (95% CI, 0.46 to 0.91) for patients reporting ≥ 9 MET-h/wk. Functional capacity was not an independent predictor of prognosis.

Conclusion

Exercise behavior is a strong independent predictor of survival that provides incremental prognostic value to KPS as well as traditional markers of prognosis in malignant recurrent glioma.
On the conditional distributions of spatial point processes
Authors: Caron François , Del Moral Pierre , Doucet Arnaud , Pace Michele
Published: June 2011

We consider the problem of estimating a latent point process, given the realization of another point process. We establish an expression for the conditional distribution of a latent Poisson point process given the observation process when the transformation from the latent process to the observed process includes displacement, thinning, and augmentation with extra points. Our original analysis is based on an elementary and self-contained random measure theoretic approach. This simplifies and complements previous derivations given in Mahler (2003), and Singh, Vo, Baddeley and Zuyev (2009).
Conditional sampling for spectrally discrete max-stable random fields
Authors: Wang Yizao , Stoev Stilian A.
Published: June 2011

Max-stable random fields play a central role in modeling extreme value phenomena. We obtain an explicit formula for the conditional probability in general max-linear models, which include a large class of max-stable random fields. As a consequence, we develop an algorithm for efficient and exact sampling from the conditional distributions. Our method provides a computational solution to the prediction problem for spectrally discrete max-stable random fields. This work offers new tools and a new perspective to many statistical inference problems for spatial extremes, arising, for example, in meteorology, geology, and environmental applications.
How fast can the chord length distribution decay?
Authors: Demichel Yann , Estrade Anne , Kratz Marie , Samorodnitsky Gennady
Published: June 2011

The modeling of random bi-phasic, or porous, media has been, and still is, under active investigation by mathematicians, physicists, and physicians. In this paper we consider a thresholded random process X as a source of the two phases. The intervals when X is in a given phase, named chords, are the subject of interest. We focus on the study of the tails of the chord length distribution functions. In the literature concerned with real data, different types of tail behavior have been reported, among them exponential-like or power-like decay. We look for the link between the dependence structure of the underlying thresholded process X and the rate of decay of the chord length distribution. When the process X is a stationary Gaussian process, we relate the latter to the rate at which the covariance function of X decays at large lags. We show that exponential, or nearly exponential, decay of the tail of the distribution of the chord lengths is very common, perhaps surprisingly so.
Hitting Times and the Running Maximum of Markovian Growth-Collapse Processes
Authors: Löpker Andreas , Stadje Wolfgang
Published: June 2011

We consider the level hitting times τy = inf{t ≥ 0 | Xt = y} and the running maximum process Mt = sup{Xs | 0 ≤ s ≤ t} of a growth-collapse process (Xt)t≥0, defined as a [0, ∞)-valued Markov process that grows linearly between random ‘collapse’ times at which downward jumps with state-dependent distributions occur. We show how the moments and the Laplace transform of τy can be determined in terms of the extended generator of Xt and give a power series expansion of the reciprocal of Ee−sτy. We prove asymptotic results for τy and Mt: for example, if m(y) = Eτy is of rapid variation then Mt / m-1(t) →w 1 as t → ∞, where m-1 is the inverse function of m, while if m(y) is of regular variation with index a ∈ (0, ∞) and Xt is ergodic, then Mt / m-1(t) converges weakly to a Fréchet distribution with exponent a. In several special cases we provide explicit formulae.
Concave Renewal Functions do not Imply DFR Interrenewal Times
Authors: Yu Yaming
Published: June 2011

Brown (1980), (1981) proved that the renewal function is concave if the interrenewal distribution is DFR (decreasing failure rate), and conjectured the converse. This note settles Brown's conjecture with a class of counterexamples. We also give a short proof of Shanthikumar's (1988) result that the DFR property is closed under geometric compounding.
National Osteoporosis Society's Position Statement on hormone replacement therapy in the prevention and treatment of osteoporosis
Authors: Bowring C E , Francis R M
Published: June 2011

Hormone replacement therapy (HRT) has been shown to increase bone density, reduce the risk of fracture and can successfully relieve menopausal symptoms. From a time when HRT was the major therapeutic option for the management of osteoporosis, women and their clinicians now have a range of treatments available. Following the publication of the Women's Health Initiative (WHI) and the Million Women Study highlighting potential side-effects, such as breast cancer, heart disease and stroke, many doctors and women are now reluctant to use HRT. The National Osteoporosis Society felt that the role of HRT in the management of osteoporosis needed to be clarified. Using the Charity's expert clinical and scientific advisers, and through public consultation with members and key stakeholders, a Position Statement has been published. We conclude that HRT has a role to play in the management of osteoporosis in postmenopausal women below the age of 60 years. The key recommendations of the Position Statement are presented in this paper.
Advice given to women undergoing gynaecological surgery in relation to menopause, symptoms and hormone replacement therapy: could and should we improve the service we provide?
Authors: Lyons Jenny
Published: June 2011

A retrospective case-note study was undertaken to look at recorded details relating to information/advice given to women prior to or at the time of their gynaecological surgery with regard to possible effects of menopause/menopausal symptoms or advice given about hormone replacement therapy.
An anomalous origin of left coronary artery and sudden death in a soccer player: a case report
Authors: Meel B L
Published: June 2011

Coronary artery anomalies, after hypertrophic cardiomyopathy, are the second most common cause of exercise-related sudden cardiac deaths. These anomalies have been associated with myocardial ischaemia, arrhythmia and sudden death during exercise. Anomalous origin of the left coronary artery from the right sinus of Valsalva with anterior or posterior courses is not always thought to be a benign anomaly. A 22-year-old man died suddenly on a football field. At autopsy, there was an abnormal origin of the left coronary artery from the right sinus of Valsalva. The abnormal course of the artery between the aorta and pulmonary trunk had limited victim's functional capacity. The history, cause of death and patho-physiology are discussed, and some preventive strategies suggested.
Benign tertian malaria – a misnomer?
Authors: Bammigatti Chanaveerappa , Shetty Sirish , Shetty Seema , Kumar Ashwini
Published: June 2011

Plasmodium vivax usually causes an acute self-limiting febrile illness with fever spikes on every third day and no complications or death. Therefore the illness caused by this parasite was termed benign tertian malaria. However, many complications associated with Plasmodium falciparum have been seen with increasing frequency with Plasmodium vivax in recent times. The present study highlights the various complications associated with Plasmodium vivax malaria.
Co-infection with hepatitis viruses among HIV-infected individuals at a tertiary care centre in South India
Authors: Kosaraju Kranthi , Padukone Shashiraja , Bairy Indira
Published: June 2011

We studied the occurrence of hepatitis B (HBV) and hepatitis C (HCV) virus co-infections in human immunodeficiency virus (HIV)-infected individuals in a tertiary care centre. The occurrence of co-infections in our study was less than in the literature reported from the West. However, routine screening of these co-infections in HIV patients is recommended to avoid possible liver-related morbidity and mortality as a part of improving their quality of life.
Blindness following visceral leishmaniasis: a neglected post-kala-azar complication
Authors: Khalil E A G , Musa A M , Younis B M , Elfaki M E E , Zijlstra E E , Elhassan A M
Published: June 2011

Visceral leishmaniasis (VL) is an important cause of morbidity and mortality that affects multiple organs. Post-kala-azar ocular involvement is a serious complication that can manifest as blepharo-conjuctivitis or pan-uveitis. Failure of prompt diagnosis and treatment can result in blindness. We report five cases with pan-uveitis that followed the successful treatment of VL and consequent post-kala-azar dermal leishmaniasis were presented. Two patients lost their sight permanently but the rest were successfully treated. A high index of suspicion and prompt treatment are of paramount importance in order to avoid blindness following post-kala-azar ocular uveitis.
Hearing Thresholds for Low-Frequency Complex Tones of Less Than 150 Hz
Authors: Ryu Jongkwan , Sato Hiroshi , Kurakata Kenji , Inukai Yukio
Published: June 2011

Hearing thresholds for low-frequency complex tones were measured to investigate effects of intensity and frequency differences between components and effects of the number of components on the detection of complexes. Complex tones comprised two tones, geometrically centered at 60 Hz, with frequency differences of 30, 60, 90, or 120 Hz. Sound pressure levels of the two tones were set to equal intensity or to equal sensation level. Additional threshold measurements were conducted for complex tones comprising 2–6 components at 25–145 Hz. A complex signal with multiple tones was detectable even if the levels of individual components were below the threshold. The improvement of complex signal detection varied greatly with the level difference and number of tones. Threshold levels for complex tones (in terms of level per component) decreased as the number of tones increased. Complex tones whose components have mutually similar frequencies were more detectable than those with separated components.
Theoretical and Experimental Study of a Prototype High-Intensity Infrasonic Acoustic Generator
Authors: Ming-Rong Dong , Ke-An Chen , Xue-Zhong Xu , Min Zhang , Hao-Zhong Ruan , Xu-Bin Liang , Bin He
Published: June 2011

The airflow modulator, which can generate the high-intensity infrasound, is a device transferring high-pressure gas energy into acoustic energy. Based on the aerodynamic theory, an airflow modulator is designed and the equivalent throat area formulas are deduced. Approximate theory is used to investigate the maximum sound pressure level, sound power, and airflow efficiency of this airflow modulator. The working mechanisms of the infrasonic acoustic generator consisting of a modulator and a Helmholtz resonator are studied by numerical simulations. In order to carry out the experiments, a prototype device was manufactured. It is shown that from the experimental results that this device can generate a continuous infrasound pressure level of 161dB in a 6 m3 test cavity. The simulation and the experimental results are reasonably consistent and it is estimated that such a device can generate an infrasound pressure level in excess of 162dB below 3Hz.
Influence of Vehicle Size, Haulage Capacity and Ride Control on Vibration Exposure and Predicted Health Risks for LHD Vehicle Operators
Authors: Eger Tammy , Stevenson Joan M , Grenier Sylvain , Boileau Paul-Émile , Smets Martin P.
Published: June 2011

Documented whole-body vibration (WBV) exposure levels at the operator/seat interface are limited for underground mining load-haul-dump (LHD) vehicles. Therefore, WBV exposure during the operation of eight small and nine large LHD vehicles, under loaded and empty haulage, was measured in accordance with ISO 2631–1 guidelines. Vibration exposure was also measured for a subsample of LHD vehicles equipped with a feature designed to reduce vibration exposure (ride-control). Operator health risks were predicted according to ISO 2631–1 health guidance caution zone (HGCZ) limits for daily vibration exposure. Vibration exposure was not significantly different for vehicle size or ride control but was significantly lower when driving with a loaded haulage bucket. All operators of small LHDs and one large LHD operator were exposed to vibration levels above the HGCZ.
Marginal Winds Leading to Competitive Rates: A Case Study in Southern Tamaulipas
Authors: Quiroga-Goode G. , Montante O. S. , Lambert T.
Published: June 2011

Wind velocity was monitored from two towers located along the shoreline in southern Tamaulipas during a year. The computed wind potential at 50 m ranges from 205 to 212 W/m2. The coastal sea breeze system on the study area is enforced by the synoptic surface flow along the year; it provides a permanency feature on the daily energy production and it also explains the higher power values in the evenings. Based on the topography and roughness maps, the database was extrapolated inland to an area of 234 km2 by solving the non-linear Navier-Stokes equations. From the estimated Annual Energy Production for several groups of turbines simulated in the area, a feasibility financial study indicates that a utility scale wind farm may produce competitive electricity rates compared to local prices, despite that wind power is merely above poor.
Control of a Wind Driven DFIG Connected to the Grid Based on Field Orientation
Authors: Hassan A.A. , Mohamed Yehia S. , El-Sawy A.M. , Mossa Mahmoud A.
Published: June 2011

Field orientation, with autonomous control of reactive power, using PI controller is the most widely used controlling method of doubly-fed induction generators (DFIG). This paper describes a method for separate control of active and reactive power of grid-connected DFIG using PI controller. Using MATLAB/SIMULINK software, the behavior of controller is evaluated during variation of wind speed. Simulation results represent the behavior of controller when facing the variations. This paper first explains the model of DFIG and the second part is explaining field oriented control of DFIG.
Wind Turbine Interference in a Wind Farm Layout Optimization Mixed Integer Linear Programming Model
Authors: Archer Rosalind , Nates Gary , Donovan Stuart , Waterer Hamish
Published: June 2011

This work develops a wind intensity interference coefficient which captures the interference caused by an upwind turbine on a downwind turbine in the same wind flow. This coefficient includes the use of a Weibull distribution to handle variability in the wind velocity, and also accounts for the geometric relationship between the turbines and the boundaries of the wind sector. This interference coefficient then forms part of a mixed integer linear program (MILP) which is used to optimise the locations of wind turbines within a wind farm site. The MILP approach is an exact method that can guarantee that the turbine locations determined by the model are optimal with respect to an a priori chosen set of possible turbine locations. Tests on an example data set (based on a demonstration case in the WindFarmer software) show, for the particular wind resource used, that interference results in a loss of power of approximately 4.2% when compared to the power production which would be predicted without accounting for interference.
The Performance of a High-Lift Airfoil in Turbulent Wind
Authors: Cao N. , Ting D. S-K. , Carriveau R.
Published: June 2011

The performance of a prospective candidate vertical axis wind turbine airfoil S1223 has been investigated at Reynolds numbers of 55,000, 75,000, and 100,000. The airfoil was tested at angles of attack from −5 to 25 deg in a quasi-isotropic turbulent flow generated using orificed plates. The independent effects of the turbulence intensity were examined with a constant integral length scale Λ/ c=0.14 (where c is the chord length). By increasing the turbulence intensity independently from 4.1 to 9.5%, the airfoil exhibits strong stall characteristics at low turbulence, whereas the stall behaviour becomes less obvious at high turbulence. The independent roles of integral length scale were examined by varying integral length Λ/ c from 0.14 to 0.23. The less turbulent free-stream with smaller length scales appears to delay the stall of the airfoil based on the observation of the lift and drag curve, implying that the smaller integral length under low turbulence intensity (4.1%) delays the boundary layer separation on the suction surface. At a higher turbulence of intensity 9.5%, the effect of varying Λ/ c from 0.08 to 0.15 only leads to subtle changes in the lift and drag.
An Experimental Investigation of a Large, Vertical-Axis Wind Turbine: Effects of Venting and Capping
Authors: Plourde B. D. , Abraham J. P. , Mowry G. S. , Minkowycz W.J.
Published: June 2011

A novel, vertical-axis wind turbine has been developed for the use in powering cellular communication towers. The new turbine takes advantage of the elevated heights of existing towers to access relatively high-speed winds. The new turbine is designed to provide local power to the cellular communication system, the electronics are designed so that the turbine stores power in a battery system when excess power is generated. This stored power is utilized at times when the wind-speed is insufficient to power the communication system. A major opportunity exists for communication towers which are located away from grid-connected electricity. In these cases, the towers are often powered by diesel generators. Through the use of turbines, it is possible to greatly reduce the diesel-fuel consumption.

Wind-tunnel tests have evaluated the potential for vented blades and blade capping for the improvement of power generation. It was found that while venting provides only marginal improvement, capping greatly increases power generation. The results also show that further improvements can be obtained through modification of the electrical system.
Noise Levels inside the Cabin of Heavy Earth Moving Machineries: Its Significance and Association
Authors: Kerketta S. , Bagh S.
Published: June 2011

Systematic monitoring of noise levels was carried out inside the cabin of all the Heavy Earth Moving Machineries deployed in a chromite mining complex during summer 2008 and winter 2009. The present study aimed to estimate the significance and the degree of association of the noise levels with respect to all the HEMMs. The analysis (t-test) shows that the equivalent noise (Leq) levels inside the cabin differ significantly with the test value of 85 dBA for all the HEMMs. Analysis of Variance reveals that the values of Leq are not identical with respect to the time of monitoring and also inside the cabins of different HEMMs (p<0.01). The Leq is the most significant during third part of time monitoring inside the cabin of the dozer (p<0.01). The Chi-square test reveals that 0.752 is the highest degree of association between the dozer, p=0.000(p<0.01) and Leq levels and exists a high degree of association.
Temperature Field Analysis of SRC-Column to SRC-Beam Joints Subjected to Simulated Fire Including Cooling Phase
Authors: Song Tian-Yi , Han Lin-Hai , Yu Hong-Xia
Published: June 2011

Three tests were performed on steel reinforced concrete (SRC) column to SRC beam joints subjected to fire scenarios including heating and cooling phases, and this paper reports the thermal part of the test results as well as the spalling observations. As these joints were designed to investigate the behaviour of a big joint zone including part of the beams and columns connected, temperatures in the junction and areas certain distance away from the junction were measured during both the heating and cooling phases. The three tests tested the influence of heating time on the temperature distributions at various sections of the specimen. A three-dimensional finite element analysis (FEA) model is developed to calculate the temperature field of the SRC column to SRC beam joints. The predicted temperatures show good comparison with the test results. Based on the finite element analysis, the differences of the temperature distributions in the joint zone and the non-joint zone are analyzed and its influence to the structural fire safety design is illustrated. One important conclusion from this study is the necessity to include cooling phase in structural safety design because it is in the cooling phase that the majority of the specimen materials reached their peak temperature.
Evaluation of the Adequacy of Development Length Requirements for 500 MPa Reinforcing Bars
Authors: Li Haitao , Su Xiaozu , Deeks Andrew J.
Published: June 2011

This paper compares the development length requirements of several international codes for 500 MPa steel reinforcing bars with test results obtained from eighteen reinforced concrete beams. These beams were designed specifically to allow the pull out of bars in the tension zone before bar yielding in order to determine the anchorage capacity and hence the development length necessary to obtain yield. After introducing the background to development length requirements and summarizing eight different international code provisions, this paper reports the results of the eighteen beam tests and compares these results with the code provisions. Following the development length comparison among the international standards, several conclusions are drawn. Of all the approaches examined in this paper, AS3600-2001 is always the most conservative one and has the worst correlation with the test data in most conditions, while AASHO has the lowest factors of safety for the smaller bars. These factors are considered reasonable and appropriate. ACI318-05 and ACI Committee 408 are more conservative and provide worse agreement for the larger bars. CEB-FIP Mode Code 1990 and Eurocode 2 always follow a similar trend and have lower, appropriate factors of safety, and also provide a better agreement with the test data in most conditions. GB50010-2002 has the similar factors of safety to CEB-FIP Mode Code 1990 and Eurocode 2. However, it doesn't provide good agreement with the test data for larger diameter bars. Of all the approaches examined here, AS3600-2009, which brings the Australian Standard into line with FIP Mode Code 1990 and Eurocode 2, provides better consistent agreement with the test data and is a significant improvement on the method provided in AS3600-2001. All current codes appear to be over conservative for small diameter bars.
Our Obsession with Curvature in RC Beam Modelling
Authors: Oehlers Deric John , Haskett Matthew , Ali Mohamed , Lucas Wade , Muhamad Rahimah
Published: June 2011

Much of the early research in reinforced concrete dealt with steel reinforcement that was both ductile and had a very strong bond with the concrete. Hence partial-interaction, that is slip between the reinforcement and concrete and subsequently debonding, has not been a major issue. This has allowed researchers to develop the two-dimensional full-interaction moment-curvature approach to model the three-dimensional behaviour of reinforced concrete. It is shown in this paper that this two-dimensional full-interaction moment-curvature approach relies on a large amount of empirical calibration to ensure a safe design. Furthermore, it is shown that a three-dimensional partial-interaction moment-rotation approach can lead to more advanced structural mechanics models of reinforced concrete behaviours and subsequently better accuracy and more versatile models.
Strength-Based Seismic Reliability of a Compliant Offshore Tower
Authors: Hasan Syed Danish , Islam Nazrul
Published: June 2011

This paper deals with the reliability analysis of a compliant offshore tower in the presence of stochastic seismic sea environment, i. e. a load combination due to long crested random sea and earthquake. Firstly, a nonlinear dynamic analysis of the said structure has been carried out for its time-domain responses. The response histories so obtained at the critical joint have been employed for its reliability analysis under ultimate shear demand. Hamilton variational principle is applied and the Lagrangian is fully developed. The analysis includes the effect of both horizontal and vertical components of large ( MW ≥ 7.0) earthquakes with near and far fault characteristics. Using the derived limit-state, reliability assessment of the joint has been carried out with computationally efficient algorithm (First order reliability method, FORM). Results are presented in terms of reliability indices and probability of failure for different seismic sea environments. The obtained results are compared with Monte Carlo simulation method. Design point, important for probabilistic design of articulated joint, located on the failure surface has been worked out.
Seismic Response of Adjacent Steel Structures Connected by Passive Device
Authors: Roh Hwasung , Cimellaro Gian P. , Lopez-Garcia Diego
Published: June 2011

In this study, the seismic response of adjacent steel structures linked to one another at different floor levels by passive devices is evaluated. Two types of connectors are considered: linear viscous dampers and linear springs. Various combinations of type and location of the connectors are analyzed for wide ranges of their characteristics. Influence of the structural properties (ratio of number of stories and ratio of fundamental periods) and the properties of the excitation (frequency) on the story response are also investigated. The results show that reduction of the story drift and the floor acceleration is not possible if the structures are connected to one another solely by the springs. However, it is feasible if the structures are linked to one another by either: (a) viscous dampers or (b) combinations of viscous dampers and springs. Herein, response reductions corresponding to case (b) are generally smaller than those corresponding to case (a). Also, the coupling control approach is more effective in controlling the response than the uncoupled approach.
Structural Damage Detection Using a Multi-Stage Particle Swarm Optimization
Authors: Seyedpoor S. M.
Published: June 2011

An efficient method is proposed to detect the multiple damages of structural systems. Natural frequency changes of a structure are considered as a criterion for damage presence. Finite element method is also employed to evaluate the required natural frequencies. A multi-stage optimization approach based on the swarm intelligence algorithm is presented to accurately identify the locations and extent of eventual damages. Test example results demonstrate the computational advantages of the proposed method to precisely determine the sites and extent of multiple structural damages.
An Investigation on Aseismic Connection with Opening in Beam Web in Steel Moment Frames
Authors: Li Bo , Yang Qingshan , Yang Na
Published: June 2011

Providing an opening in a beam web (OBW) is a possible approach to improving the aseismic behaviour in beam-to-column connections in steel moment frames. The finite element analysis in this paper shows that the behaviour of the OBW connection depends on a size of the opening, R, and the opening location, b. When parameters are properly selected, Vierendeel hinges form in the weakened areas resulting in a beam with high ductility. Quasi-static tests were carried out based on the finite element analysis results. The test results showed that Vierendeel hinges formed in the weakened areas and brittle weld fracture was avoided in the OBW connections. The performance indicators of the OBW connection are not reduced with a weakened section. Aseismic behaviour of the beam-to-column connections are improved with an opening in the beam web. To explain the failure mechanism of the OBW connection, the stress distribution obtained from the finite element analysis was studied. The stress distribution around the opening was found dramatically changed because of the provision of the opening. Four plastic zones formed in the web around the opening under the interaction of normal and shear stresses at the critical locations resulting in ductile Vierendeel hinges.
Verification of a Cable Element for Cable Parametric Vibration of One-Cable-Beam System Subject to Harmonic Excitation and Random Excitation
Authors: Xia Yong , Wu Qing-Xiong , Xu You-Lin , Fujino Yozo , Zhou Xiao-Qing
Published: June 2011

Nonlinear vibration of cables in cable-stayed bridges is usually studied by either a divide-and-conquer approach in which interaction between local motion of the cables and global motion of the bridge is not considered, or a coupled cable-beam system which can only represent a simple structure with few degrees of freedom. A cable finite element is presented in this paper which can account for in-plane and out-of-plane motions of the cable. A cable-beam system with frequency ratio of 1:1:2 is employed to verify feasibility of the cable element in analysing nonlinear vibration of the stay cable. Vibrations of the coupled cable-beam system under harmonic and random loadings are calculated and compared with the available analytical solutions that have been verified experimentally. The results demonstrate that the cable finite element can capture nonlinear vibration, in particular auto-parametric vibration of stay cables under both loading cases. Consequently it can be applied to practical structures with multiple cables.
Aeroacoustic Waves Generated from a Supersonic Jet Impinging on an Inclined Flat Plate
Authors: Nonomura Taku , Goto Yoshinori , Fujii Kozo
Published: June 2011

This paper presents a computational study of the flow and flow-induced acoustic fields of a supersonic jet impinging on an inclined flat plate. For the numerical simulations, we solved three-dimensional compressible Navier-Stokes equations with a modified weighted compact nonlinear scheme. We analyzed the simulation results mainly from the viewpoint of the acoustic emission and propagation mechanism, and we investigated the acoustic field characteristics such as directivity, their spectra, and acoustic wave source positions. The acoustic fields indicate that there are at least three types of acoustic waves in all the cases considered in the study: (i) Mach waves generated from the shear layer of the main jet, (ii) acoustic waves generated from the impingement region, and (iii) Mach waves generated from the shear layer of the supersonic flow downstream of the jet impingement. The indication of the second type of wave (ii) is important because the commonly used empirical method for the estimation of the acoustic waves from a rocket plume does not consider such acoustic waves. We also discussed the effects of nozzle-plate distance and temperature on the second type of acoustic waves (ii).
Helicopter Rotor Noise in the Merged Tip-Vortex and Blade Interaction Condition
Authors: Wie S. Y. , Im D. K. , Kwon J. H. , Lee D. J. , Chung K. H. , Kim S. B.
Published: June 2011

BVI (blade vortex interaction) phenomena cause unsteady loading and noise in the helicopter rotor. It is difficult to accurately predict BVI aerodynamics and noise, because rotor wake and tip-vortices are numerically dissipated. In the present study, CFD and a time-marching free-wake coupling analysis were used to describe inflow and outflow without wake dissipation. Rotor noise was also computed using the Farassat formula, derived from the Ffowcs-Williams Hawkings equation. To validate aerodynamics and the noise prediction solver, a two-blade rotor was simulated and the results were compared with experimental data.

To investigate the vortex interaction of a multi-blade rotor, a four-blade rotor was also simulated. In a slow descent flight condition, tip vortices are merged at the advancing side. The merged tip-vortex and blade interaction were simulated and are discussed in this paper.
Computation of Bio-Fluid Sounds
Authors: Bae Youngmin , Moon Young J.
Published: June 2011

A hybrid method is proposed for prediction of bio-fluid sounds at very low Mach numbers. The unsteady hydrodynamic flow field is computed by the incompressible Navier-Stokes equations (INS), while the sound field is obtained by solving the linearized perturbed compressible equations (LPCE) with sound sources represented by a total derivative of the hydrodyanmic pressure, DP/ Dt. With the present INS/LPCE hybrid method, the vocal sound in human larynx and the buzz sound of bumblebee are computed with more clear understanding on the sound generation processes associated with their characteristic motions such as the self-sustained oscillatory motions of the vocal folds and the figure-eight motion of the flapping wings.
Embedded Rationality: A Unified Simulation Framework for Interactive Form Finding
Authors: Attar Ramtin , Aish Robert , Stam Jos , Brinsmead Duncan , Tessier Alex , Glueck Michael , Khan Azam
Published: June 2011

This paper describes embedded rationality as a method for implicitly combining fabrication constraints into an interactive framework for conceptual design. While the concept of ‘embedded rationality’ has been previously discussed in the context of a parametric design environment, we employ this concept to present a novel framework for dynamic simulation as a method for interactive form-finding. By identifying categories of computational characteristics, we present a unified physics-solver that generalizes existing simulations through a constraint-based approach. Through several examples we explore conceptual approaches to a fixed form where the resulting effects of interacting forces are produced in real-time. Finally, we provide an example of embedded rationality by examining a constraint-based model of fabrication rationale for a Planar Offset Quad (POQ) panelization system.
Computational Environments with Multimodal Representations of Architectural Design Knowledge
Authors: Aksamija Ajla , Iordanova Ivanka
Published: June 2011

This article discusses interaction between multimodal representations of architectural design knowledge, particularly focusing on relating explicit and implicit types of information. The aim of the presented research is to develop a computational environment that combines several modes of representation, including and integrating different forms of architectural design knowledge. Development of an interactive digital-models library and ontological model of architectural design factors are discussed, which are complementary in nature. In a time when BIM software is seen as embodiment of domain knowledge and the future medium of architectural design, this paper presents an interaction between ontological representation of architectural design knowledge and its embodiment in interactive models, thus focusing on the process of design and design space exploration. In the digital environments that we propose, representation of different formats of knowledge, such as visual, linguistic or numeric, are integrated with relational and procedural information, design rules, and characteristics. Interactive search and query based on contextual constraints, and parametric variation of the model based on the information received from ontology are the underlying drivers for design exploration and development.
ViSA: A Parametric Design Modeling Method to Enhance Visual Sensitivity Control and Analysis
Authors: Erhan Halil , Salmasi Nahal H. , Woodbury Rob
Published: June 2011

The ability of parametric computer-aided design systems to generate models rapidly enables designers to explore the downstream impacts of changes to key design parameters. However, the typical modeling functions provided in the parametric systems can become insufficient when such exploration is needed for increasingly complex parametric design models. Main challenges for exploration that we observed are control and analysis of changes on the design model and in particular, when they are introduced continuously. The system interfaces and the human-visual perception system alleviate these challenges. In this study, we demonstrate ViSA, a Visual Sensitivity Analysis method that aims to make the effects of change within a parametric model controllable, measurable and apparent for designers. The approach aims to improve visually analyzing the sensitivity of a design model to planned parametric changes. The method proposes customizable control and visualization features in the model that are decoupled from each other at the design level, while providing interfaces between them through parametric associations. We present findings from our case studies in addition to the results of a user study demonstrating the applicability and limitations of the proposed method.
Surface Symmetries: The Smith House Revisited
Authors: Din Edouard , Economou Athanassios
Published: June 2011

This work proposes the use of partial order lattices along with representational schemes to account for patterns of ambiguity and emergence in the description of designs. The complexity of such designs is viewed as an aggregation of spatial layers that can all be decomposed by the subgroup relations of the symmetry of the configuration. At the end, this methodology points to a combinatorial approach that generates visual prototypes for future use in design synthesis. Here, Meier's work is just a case study that validates the group theoretical approach.
Lighting Intention Materialization with a Light-Based Parametric Design Model
Authors: Tourre Vincent , Miguet Francis
Published: June 2011

How the inverse lighting methods could help the architectural design? We address this issue with an original light-based parametric design model dedicated to the architectural design. This model associates the parametric design approach with the lighting intentions expressed by the architects. It has been implemented thanks to an inverse lighting technique in a tool intended to aid the design of the windows and the shading devices in the early stages of architectural design. This model is used in a performative design approach onto the dome of the Louvre Abu Dhabi museum in order to define the transparency property of the dome.
Function Follows Performance in Evolutionary Computational Processing-Vertical Evolution
Authors: Pasold Anke , Foged Isak Worre
Published: June 2011

As the title ‘Function Follows Performance in Evolutionary Computational Processing’ suggests, this paper explores the potentials of employing multiple design and evaluation criteria within one processing model in order to account for a number of performative parameters desired within varied architectural projects. At the core lies the formulation of a methodology that is based upon the idea of human and computational selection in accordance with pre-defined performance criteria that can be adapted to different requirements by the mere change of parameter input in order to reach location specific design solutions.
A Design Studio Pedagogy for Experiments with Unusual Material, Collaboration and Web Communication
Authors: Nováková Kateřiná , Achten Henri , Matějovská Dana
Published: June 2011

In this paper we describe an experimental CAD design studio, where we study the influence of CAD tools and special materials on the process of designing. The studio has the following aims: teaching how to collaborate using an Internet facility, and exploring the relationship between computation, sketching and physical models. Interaction and sustainability are major themes in the design studio. We present the pedagogical approach and results of the design studio, followed by observations and conclusions.
Simulation of a proton exchange membrane fuel cell
Authors: Hasan A. , Guo S. , Wahab M.
Published: June 2011

Performance prediction of a proton exchange membrane fuel cell (PEMFC) has been studied using a multiphysics-based numerical simulation. The simulated geometry was a simple channel, in which the multi species transportation in the porous electrodes and the coupled electrical current and potential distributions were modeled. The 3D simulations provide the cell performance curve and the fuel/oxidant concentration distributions along the feeding channel. To obtain the detailed flow field in the porous gas diffusion layer, a 2D simulation was also performed. The simulations were compared with the available experimental data for a single channel PEMFC and the comparisons are favorable.
Improved arc discharge setup for synthesis of single and multi walled carbon nanotubes
Authors: Haneef M. , Abdo Jamil , Ullah Syed , Waqar S. , Hussain Fayaz , Ali Ashraf
Published: June 2011

This paper presents development of a laboratory scale setup for production of CNTs by arc discharge process in an argon gas environment. The main problem with existing lab scale production is the cleaning of the chamber which is resolved in presented work by placing a circular metal sheet inside the chamber which is removed after the synthesis, thus allowing easy cleaning and recovery of the CNTs. The most noteworthy feature of the presented setup is its low cost, offering for the first time the synthesis of economical CNTs on small scale. In addition to offering better control over operating conditions, another unique feature of the developed setup is its capability to synthesize SWCNTs and MWCNTs with versatile range of diameters.
Three-dimensional active earth pressure behind pile and screen by applying the kinimatics theory
Authors: Benyaghla H. , Meksaouin M. , Belabed L.
Published: June 2011

Two theoretical models very simple in calculation of active earth pressure of prism of three-dimensional rupture mobilised behind pile or screen in translation, were proposed. Improvements were done in order to pass from one to another, by the introduction of frustum of cone, which permits to obtain forms of prism of rupture more near to the reality. Basing on Kinematics Theorem of Drucker and Prager of limit analysis theory, there models give, in this way, two boundary-stones or superiors limits of this active earth pressure according to real value of this last. This is effectively well verified on experimental trials realized.