bluuebunny/crossref_metadata_2025 huggingface dataset:
Fuzzy control with estimated variable sampling period for non-linear networked control systems: 2-DOF helicopter as case study
Authors: Méndez-Monroy PE , Benítez-Pérez H
Published: September 2011

This paper presents a fuzzy controller for class of non-linear networked control systems; the varying time delays and packet loss are taken as a variable sampling period of the system. The variable sampling period is estimated using a time stamped and probability density function. A fuzzy model smoothly switches to estimate the system state; the antecedent input is the estimated sampling period and the consequent part is formed by linear models discretized with specific sampling periods. The fuzzy controller generates a control input using the estimated states to ensure system stability for a wide range of sampling periods. A two-degree-of-freedom helicopter is used to show the applicability and effectiveness of the controller with robustness to traffic.
Patient inclusion in goal setting during early inpatient rehabilitation after acquired brain injury
Authors: Dalton Catherine , Farrell Rachel , De Souza Annette , Wujanto Evelyn , McKenna-Slade Ann , Thompson Sharmen , Liu Clarence , Greenwood Richard
Published: September 2011

Objective: To investigate the effects of patient participation in multidisciplinary goal setting during early inpatient rehabilitation after acquired brain injury.

Design: Case controlled retrospective study.

Setting: Regional neurological rehabilitation unit.

Subjects: One hundred and five patients with acquired brain injury.

Main measures: Numbers of goals set and achieved per patient before and after intervention; Barthel Index and Functional Independence Measure.

Results: The intervention resulted in a significant increase in the number of goals set per patient (340 versus 411 total goals, mean per patient 6.3 pre versus 8.05 post, P = 0.008). More patients had multiple goals set within each domain ( P = 0.023). There was an increase in the number of patients with sleeping (0 pre, 9 post), continence (3 pre, 17 post) and leisure (15 pre, 35 post) goals set, and leisure goals achieved (60% pre and 68% post, P < 0.001). Correlations between goal achievement and change in activity-related outcome measures (Barthel Index and Functional Independence Measure) also improved with the new goal setting process. The proportion of goals achieved remained similar (60% pre and 63% post intervention), suggesting there was no evidence of inappropriate or unachievable goals set when the patient and family were included.

Conclusions: Real-time engagement of brain-injured patients in the goal setting process during early inpatient rehabilitation is achievable, but requires a structured multidisciplinary assessment of need. We found it increases the number of domains in which goals are set and includes functional areas not rated by commonly used global measures of outcome during inpatient rehabilitation.
Safety and self-reported efficacy of botulinum toxin for adult spasticity in current clinical practice: a prospective observational study
Authors: Muller François , Cugy Emmanuelle , Ducerf Camille , Delleci Claire , Guehl Dominique , Joseph Pierre-Alain , Burbaud Pierre , Dehail Patrick
Published: September 2011

Objective: To determine the safety and the self-reported efficacy of botulinum toxin injections for adult spasticity in current clinical practice.

Design: A prospective observational study.

Subjects: A total of 406 adult patients with focal spasticity received of 1136 series botulinum toxin injections at Bordeaux University Hospital from January 2007 to December 2009.

Methods: Adverse events following botulinum toxin injections were reported. Their severity and the therapeutic efficacy of botulinum toxin injections were estimated with a four-point self-reporting scale (0 to 3). Latency and duration of adverse events and subjective improvement were also noted.

Results: The data of 640 series of injections were analyzed. Forty-six (7.2%) adverse events were reported, of which 36 (78%) were local. There were 18 (39%) cases of local muscular weakness with an average duration of 30.0 (SD 38.2) days, and an average severity score of 1.0 (SD 0.97). Among systemic adverse events, there were 8 (17%) cases of excessive fatigue without global muscular weakness and 2 (4%) cases of transitory generalized muscular weakness. The average subjective improvement score was 1.89 (SD 0.97) and was higher for upper, than for lower, limbs ( P=0.007).

Conclusion: Self-reported adverse events following botulinum toxin injections in spasticity are rare, often benign and of short duration in current clinical practice. Botulinum toxin is considered effective by patients in treating spasticity of the upper and lower limbs.
Community-based Yang-style Tai Chi is safe and feasible in chronic stroke: a pilot study
Authors: Taylor-Piliae Ruth E , Coull Bruce M
Published: September 2011

Objective: Examine the safety and feasibility of a 12-week Tai Chi intervention among stroke survivors.

Design: Two-group, prospective pilot study with random allocation.

Setting: Outpatient rehabilitation facility.

Subjects: Stroke survivors ≥50 years and at ≥three months post-stroke.

Interventions: Tai Chi subjects attended group-based Yang Style classes three times/week for 12-weeks, while Usual Care subjects received weekly phone calls along with written materials/resources for participating in community-based physical activity.

Main outcome measures: Indicators of study safety and feasibility included recruitment rates, intervention adherence, falls or adverse events, study satisfaction, drop-outs, and adequacy of the outcomes measures.

Results: Interested persons pre-screened by phone ( n = 69) were on average 68 years old, (SD = 13) years old, 48% ( n = 33) women, 94% ( n = 65) were at least three months post-stroke. A total of 28 subjects aged 69 (SD = 11) years enrolled in this pilot study. Intervention adherence rates were very high (≥92%). There were no falls or other adverse events. The dose of Tai Chi exercise (≥150 minutes/week) was well tolerated. Overall study satisfaction was high (8.3 (SD = 1.9); 1 = not satisfied, 10 = most satisfied), while drop-outs ( n = 3, 11%) were unrelated to study intervention. Score distributions for the outcome measures were approximately normal, sensitive to change, and seemed to favor the Tai Chi intervention.

Conclusions: Tai Chi is a safe, community-based exercise program for stroke survivors. Our data suggest that recruitment and retention of an adequate sample is feasible, and that in a full-scale study 52 subjects/group are needed to detect statistically significant between group differences (alpha = 0.05, power = 0.80).
Alcohol stress response dampening: selective reduction of anxiety in the face of uncertain threat
Authors: Hefner Kathryn R , Curtin John J
Published: September 2011

Problematic alcohol use and stress response dampening (SRD) are intimately interconnected. Recent evidence suggests that alcohol produces selective SRD during uncertain but not certain threat. We systematically varied shock probability in a novel task assessing alcohol SRD during low probable/uncertain threat, while holding temporal precision of threat constant. Intoxicated (0.08% target blood alcohol concentration) and placebo participants completed a cued shock threat task in which probability of shock administration at the offset of brief visual cues varied parametrically. High probability (100%) shock cues represented certain threat as used in earlier research, while lower probability (20% and 60%) shock cues provided novel uncertain threat conditions. Startle potentiation during cues and inter-trial intervals (ITIs) served as the measure of affective response. General linear model analysis indicated that alcohol SRD magnitude increased monotonically as threat uncertainty increased. Alcohol SRD was significantly greater during 20% and 60% shock threat relative to 100% shock threat. Alcohol also significantly reduced startle potentiation during distal threat in shock-free ITIs. Alcohol SRD magnitude during distal/uncertain threat was meaningfully moderated by individual differences in negative affectivity and weekly alcohol consumption. This work advances understanding of which properties of uncertainty are relevant to anxiety and anxiolytic effects of alcohol.
Does the Importance of Parent and Peer Relationships for Adolescents’ Life Satisfaction Vary Across Cultures?
Authors: Schwarz Beate , Mayer Boris , Trommsdorff Gisela , Ben-Arieh Asher , Friedlmeier Mihaela , Lubiewska Katarzyna , Mishra Ramesh , Peltzer Karl
Published: September 2011

This study investigated whether the associations between (a) the quality of the parent-child relationship and peer acceptance and (b) early adolescents’ life satisfaction differed depending on the importance of family values in the respective culture. As part of the Value of Children Study, data from a subsample of N = 1,034 adolescents (58% female, M age = 13.62 years, SD = 0.60 years) from 11 cultures was analyzed. Multilevel analyses revealed a positive relation between parental admiration and adolescents’ life satisfaction independent of cultural membership. Further, the higher the importance of family values in a culture, the weaker was the positive effect of peer acceptance on adolescents’ life satisfaction. The results highlight the universal importance of parental warmth and support in adolescence and underline the effect of culturally shared family values on the role of peer acceptance for adolescent development.
Macromarketing Roundtable Commentary—The Export of Marketing Education
Authors: Bradshaw Alan , Tadajewski Mark
Published: September 2011

It is increasingly common for western universities to recruit marketing students from across the globe, and in particular from notionally “developing” economies. This practice raises questions across a variety of issues: It can smuggle discourses of subalternity into the classroom; it can construct marketing education as an agent of globalization; it can undermine commitments to maintaining criticality in the subject area; it can result in all manners of pedagogical challenges; it can raise huge amounts of money for universities; and it can reconstitute marketing education as an object for export. These issues get to the heart of marketing education in an age of ever-increasing commercialization of universities and general tendencies of neoliberalism. To explore the phenomenon, an interdisciplinary roundtable discussion was held at Royal Holloway, University of London, on September 8, 2010. The participants here present short statements outlining their positions regarding marketing education, not just as a subject for teaching and learning but also as a product for export at a time of globalization, neoliberalism and political–economic transformations.
Maximum equivalent stress in a pin-loaded lug in the presence of initial clearance
Authors: Strozzi A , Baldini A , Giacopini M , Bertocchi E , Bertocchi L
Published: September 2011

Various design charts of ample validity and prompt access are presented, which permit the contact stresses within the lug of a pinned connection to be forecast in the presence of an initial clearance between the pin periphery and the lug bore. To cover the range of the practically encountered geometries and loadings, round-ended lugs of various widths and with a variously tapered shank are considered, and several inclinations of the applied load are addressed. The charts are compiled with the aid of finite elements. The employment of the recently proposed load factor Φ allows the combined effects on the peak contact stresses of the load intensity and of the initial clearance to be predicted.
Effects of dichlorvos and carbaryl on the activity of free and immobilized acetylcholinesterase
Authors: Qujeq D , Roushan T , Norouzy A , Habibi-Rezaei M , Mehdinejad-Shani M
Published: September 2011

Acetylcholinesterase (AChE) is responsible for the rapid hydrolytic degradation of the neurotransmitter acetylcholine into inactive products choline and acetic acid. The purpose of this study was to examine the effect of carbaryl and dichlorvos on the activity of AChE. In this experimental study, 60 samples of free and immobilized form of AChE were prepared. Determination of AChE activity followed the Ellman’s method with modifications. Briefly, 200 µl of the enzyme solution was combined with 400 µl of 25 mM phosphate-buffered saline, 200 µl of DTNB [5,5′-dithio-bis(2-nitrobenzoic acid)], and 200 µl of 300 μM acetylthiocholine iodide. Triplicate (1000 µl) samples were transferred to clean 1.5-ml centrifuge tubes, mixed, and held on ice until analysed and the change in absorbance was measured. For inhibition studies, substrate solutions were pre-incubated with dichlorvos and/or carbaryl. Dichlorvos and carbaryl were used at the concentrations of 100 and 500 μM. The activity was evaluated at 412 nm using Ceceil, CE 1020 spectrophotometer. Phosphate buffer (pH 7.35) was used for blanks. AChE activity was quantified as mM/ml/min. AChE activity of free form is more affected by Dichlorvos (0.09 ± 0.03 mM/ml/min) than immobilized form (0.19 ± 0.02 mM/ml/min). AChE activity of free form is more affected by carbaryl (0.11 ± 0.01 mM/ml/min) than immobilized form (0.1 ± 0.04 mM/ml/min). Comparison of mean AChE activity showed that the activity of the enzyme in presence of dichlorvos and carbaryl was significantly lower compared to controls. To calculate the significance of the difference, the t-test for paired values was applied. The results of our study indicate that dichlorvos and carbaryl cause decrease in AChE activity for both free and immobilization form of enzyme. It is therefore concluded that measuring AChE activity is a way to evaluate poisoning with carbaryl and dichlorvos.
The genotoxic potentials of some atypical antipsychotic drugs on human lymphocytes
Authors: Togar Başak , Turkez Hasan , Tatar Abdulgani , Kırkpınar Ismet , Hacımuftuoglu Ahmet , Geyikoglu Fatime , Keles M Sait , Dirican Ebubekir
Published: September 2011

Olanzapine (OLZ), risperidone (RPD) and quetiapine (QTP) are atypical antipsychotic drugs and are commonly used for the treatments of schizophrenia and bipolar disorders. However, recent reports indicated that these drugs could exhibit toxic effects on nervous and cardiovascular systems. To our best knowledge, there are scarce data considering the genotoxic damage potentials of OLZ, RPD and QTP on human lymphocyte culture system. Therefore, in this study, the genotoxic potentials of OLZ, RPD and QTP (0–400 mg/L) have been evaluated in human whole blood cultures (WBCs; n = 4). The single cell gel electrophoresis (SCGE) and micronucleus (MN) assays were applied to estimate the DNA damage. The results of the present study indicated that the tested antipsychotic drug did not induce genotoxicity. In fact, the mean values of the total scores of cells showing DNA damage (for SCGE assay) and MN/1000 cell were not found significantly different from the control values ( p > 0.05). However, the application of the highest drug concentrations (250 mg/L and above) caused the sterility in lymphocyte cultures. It is concluded that the tested three different atypical antipsychotic drugs can be used safely, but it is necessary to consider the cytotoxic effects that are likely to appear depending on the doses exposed.
Morphological changes of ricin toxin-induced apoptosis in human cervical cancer cells
Authors: Liao Peng , Liu Wensen , Li Hongyang , Gao Hongwei , Wang Haiying , Li Nan , Xu Na , Li Jiping , Wan Jiayu , Liu Linna , Sun Yucheng
Published: September 2011

The morphological changes of ricin-induced apoptosis in a human cervical cancer cell line were studied. To shed light on the mechanism of action of ricin toxin (RT) at the cellular level, we examined cell growth, apoptosis, changes of mitochondrial membrane potential (MMP) and cytochrome C translocation in HeLa cells by exposing these cells to RT for indicated times. The effect of RT on cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), inner salt; MTS assay and apoptosis were measured using flow cytometry, fluorescence microscopy and electron microscopy. Changes in MMP were monitored using flow cytometry. Western blot analysis was used to evaluate the release of mitochondrial cytochrome C. RT noticeably inhibited the proliferation of HeLa cells, and the half maximal inhibitory concentration dose was about 100 ng/ml. HeLa cells treated with RT showed typical characteristics of apoptosis rather than necrosis, including phosphatidylserine exposed from the inner to the outer leaflet of the plasma membrane, abnormal cell morphology, chromatin condensation and nuclear fragmentation. In contrast, during the process of cellular apoptosis, the messenger RNA (mRNA) and protein expression of cytochrome C in treated and untreated Hela cells were not significantly changed (data not shown). However, when cells were treated with RT, the massive translocation of cytochrome C to the nucleus was evident. Our results indicate that RT-induced HeLa cell apoptosis, especially for cytochrome C translocation, may play an important role in apoptosis induced by RT.
Reduction of pollutants in painting operation and suggestion of an optimal technique for extracting titanium dioxide from paint sludge in car manufacturing industries—case study (SAIPA)
Authors: Khezri Seyed Mostafa , Shariat Seyed Mahmood , Tabibian Sahar
Published: September 2011

Paint sludge of car manufacturing industries are not disposed in landfills, since they contain hazardous materials with a high concentration of chromium, aluminum, titanium, barium, copper, Iron, magnesium, strontium, and so on. Thus, it is essential to find solutions in order to neutralize them or suggest cost-effective techniques, which are also environmentally acceptable. Because, this sludge contains considerable amounts of Ti pigments and unbaked resins, recycling these pigments—which could be used in a variety of industries such as paint factories— is an appropriate subject for further research. In this article, with the aim of identification of main pollutants in order to eliminate them and suggest a cost-effective solution to recover the sludge, a large number of tests including X-ray fluorescence spectroscopy, X ray diffraction spectroscopy, and diffusion thermal analysis are conducted to determine types and concentration of elements, and combinations of paint sludge in car manufacturing industries. As titanium dioxide (TiO2) is widely used as the main pigment of automobile paints, an optimal technique is suggested for extracting TiO2 with high purity percentage through adopting scientific methods such as membrane and electrolysis.
Differential oxidative stress responses to methanol in intraperitoneally exposed rats: ameliorative effects of Opuntia vulgaris fruit extract
Authors: Saoudi Mongi , Hsouna Anis Ben , Trigui Mohamed , Jamoussi Kamel , Jaoua Samir , Feki Abdelfattah El
Published: September 2011

Methanol is primarily metabolized by oxidation to formaldehyde and then to formate. These processes are accompanied by formation of superoxide anion and hydrogen peroxide. This article reports data on the effect of methanol-induced oxidative damage in experimental rats and the role of aqueous extract of Opuntia vulgaris fruit extract (OE) to counteract the toxicity induced by methanol. The animals were exposed to methanol at a dose of 2.37 g/kg body weight intraperitoneally for 30 days. OE was found to contain large amounts of polyphenols and carotenoids and significant antioxidant capacities highlighted by scavenging activities for 2,2-diphenyl-l-picrylhydrazyl. The treatment with methanol exhibited a significant increase in serum hepatic and renal biochemical parameters (alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, lactate dehydrogenase, bilirubin, urea, and creatinine). Methanol intoxication significantly increased hepatic and renal lipid peroxidation evaluated by thiobarbituric acid reactive substances in treated rats as compared to controls. However, hepatic and renal antioxidant enzymes namely superoxide dismutase, catalase, and glutathione peroxidase were significantly decreased in methanol-treated animals as compared to controls. The results concluded that treatment with OE prior to methanol intoxication has significant role in protecting animals from methanol-induced hepatic and renal histopathological and oxidative damage.
Addressing Sustainable Apparel Design Challenges With Problem-Based Learning
Authors: Gam Hae Jin , Banning Jennifer
Published: September 2011

As consumers' social and environmental concerns have grown in the last decade, so has interest in eco-fashion. Behind fast-changing fashion trends, the apparel industry generates substantial environmental and resource depletion problems throughout the textile lifecycle. To respond to these trends, fashion designers and merchandisers have been motivated to practice sustainability in design and production. Some sustainable options are available, such as organic fibers and environmentally safe dyes. Still, there are challenges for apparel designers and merchandisers when trying to realize sustainability. To help undergraduate apparel students learn problem-solving approaches to sustainable garment design, a problem-based learning project was created and implemented in an undergraduate design course. In the course, students designed and produced an original sustainable garment. Student feedback following the project was largely positive, with most students indicating they would continue using sustainable practices in future work.
University Historic Clothing Museums and Collections
Authors: Marcketti Sara B. , Fitzpatrick Janet E. , Keist Carmen N. , Kadolph Sara J.
Published: September 2011

University historic dress collections and museums provide unique opportunities to actively fulfill critical mission statements of the university, including possibilities for research projects, providing firsthand opportunities for students to view real-life objects, and outreach/service opportunities to the public. Despite the importance of collections in fulfilling university missions, research about current practices and best practices is scarce. The purpose of this study was to document practices, challenges, and opportunities for excellence experienced by university collections within the United States. To explore the topic, a qualitative methodology in which 14 curators and collection managers were interviewed was utilized. The results of this study suggest that many curators and collection managers endure many similar struggles within their departments, such as lack of financial resources, time, and support from upper administration. Yet, all of the participants stated the significant contributions and impact material culture can have on the mission of their institutions.
Impact of Wearing Body Armor on Lower Body Mobility
Authors: Park Huiju , Nolli Giovanni , Branson Donna , Peksoz Semra , Petrova Adriana , Goad Carla
Published: September 2011

This study investigates the effect of wearing body armor while walking on lower body mobility using a motion capture system. Seven male participants participated in a walking test while markers were attached to anatomical points on their joints under two garment conditions. The treatment garment was an 18-lb ballistic outer tactical vest with inserted ceramic front and back plates and the control garment was a pair of sports shorts. The walking test was repeated 5 times per subject. Wearing the outer tactical vest significantly increased stance phase, double support, knee flexion, foot plantar flexion at the ankle, and anterior pelvic tilt. Wearing the outer tactical vest significantly decreased swing phase, posterior pelvic tilt, and pelvic rotation. The increase in knee flexion and plantar flexion while wearing the outer tactical vest may accelerate fatigue and increase energy expenditure, which can negatively affect soldiers' performance and safety by increasing injury risk.
Study on the mechanical, degradation, and interfacial properties of calcium alginate fiber-reinforced polyethylene oxide composites
Authors: Dey Kamol , Khan Ruhul A. , Chowdhury A. M. Sarwaruddin
Published: September 2011

Calcium alginate fibers (CAFs) were prepared from sodium alginate, which is a natural polymer extracted from brown seaweeds, by extruding aqueous sodium alginate solution (4% by weight) into a calcium chloride (2% by weight) bath. Water uptake of CAF was determined in deionized water at room temperature (25°C) and it was found that the fibers absorbed 49% of water within a minute and indicated strong hydrophilic nature. Polyethylene oxide (PEO) based CAF (as a filler/reinforcing agent) reinforced unidirectional composites (10% fiber by weight) were fabricated by compression molding. Tensile strength, tensile modulus, bending strength, bending modulus, and impact strength of the PEO/CAF composite were found to be 11 MPa, 320 MPa, 18 MPa, 565 MPa, and 12 kJ/m2, respectively. Degradation tests of the PEO/CAF composites were performed for 8 weeks in soil medium and it was found that composites retained almost 50% of its original strength. The interfacial shear strength (IFSS) of the PEO/CAF composites was also measured by single fiber fragmentation test. The IFSS was found to be 0.47 MPa that indicated good fiber–matrix adhesion.
T.R.U.S.T.
Authors: Barss Karen Scott
Published: September 2011

Literature across health care disciplines has come to acknowledge spiritual care as integral to holistic health promotion. However, caregivers often continue to be reluctant to explore the spiritual dimension of health with their clients. In order to help caregivers feel more prepared to offer spiritual care, the author has drawn upon the interdisciplinary literature to develop the T.R.U.S.T. Model for Inclusive Spiritual Care. This article introduces the T.R.U.S.T. Model and its foundational concept of ‘inclusive spiritual care’: relevant, non-intrusive care which tends to the spiritual dimension of health by addressing universal spiritual needs, honoring unique spiritual worldviews, and helping individuals to explore and mobilize factors that can help them gain/re-gain a sense of trust in order to promote optimum healing. The article also describes the T.R.U.S.T. Model’s origins, underlying assumptions, and its non-prescriptive outline for exploring five topics: ‘Traditions’, ‘Reconciliation’, ‘Understandings’, ‘Searching’, and ‘Teachers’. Guidelines are included for using T.R.U.S.T. to enhance holistic health care, with an emphasis on its use in holistic nursing practice.
Design of experiments for non-manufacturing processes: benefits, challenges and some examples
Authors: Antony J , Coleman S , Montgomery D C , Anderson M J , Silvestrini R T
Published: September 2011

Design of Experiments (DoE) is a powerful technique for process optimization that has been widely deployed in almost all types of manufacturing processes and is used extensively in product and process design and development. There have not been as many efforts to apply powerful quality improvement techniques such as DoE to improve non-manufacturing processes. Factor levels often involve changing the way people work and so have to be handled carefully. It is even more important to get everyone working as a team. This paper explores the benefits and challenges in the application of DoE in non-manufacturing contexts. The viewpoints regarding the benefits and challenges of DoE in the non-manufacturing arena are gathered from a number of leading academics and practitioners in the field. The paper also makes an attempt to demystify the fact that DoE is not just applicable to manufacturing industries; rather it is equally applicable to non-manufacturing processes within manufacturing companies. The last part of the paper illustrates some case examples showing the power of the technique in non-manufacturing environments.
Approaches for component degradation modelling in time-varying environments with application to residual life prediction
Authors: You M-Y , Meng G
Published: September 2011

This article explores two approaches for modelling the effect of time-varying environmental conditions on the degradation processes of systems subject to linear/exponential degradation, and derives the procedures for applying the approaches to real-time residual life prediction. The first approach, namely the look-up table (LUT) approach, accesses the effect of environmental conditions empirically from historical data without artificially imposing any additional term on the classical stochastic linear degradation model, provided that the historical training data covers all possible finite environmental conditions. The second approach, namely the multiplicative acceleration effect (MAE) approach, regards that the environmental condition has a multiplicative acceleration/deceleration effect on component degradation rate, and is applicable to the case when the historical data only partially covers the possible finite/infinite environmental conditions. In approach development, the parameter estimation algorithms are explicitly derived so that the historical training samples with time-varying environmental conditions can be used to estimate the prior distributions of component degradation rate. Several numerical experiments designed based on real degradation data of ball grid array solder joints are conducted to evaluate the proposed approaches. The experimental results verify the superiority of the proposed approaches over the classical approach which simply ignores the effect of environmental conditions. The LUT approach slightly outperforms the MAE approach when they are both applicable. On the other hand, the MAE approach still performs well in presence of new environmental conditions.
Analysis of combined cooling, heating, and power systems operating following the electric load and following the thermal load strategies with no electricity export
Authors: Fumo N , Mago P J , Smith A D
Published: September 2011

Technologies such as cogeneration and trigeneration have great potential for energy and emission reduction because these technologies make better use of fuels by recovering waste heat to satisfy thermal loads. Operation of a system that involves several types of equipment operating as one unit, that at the same time interact with the building to meet its energy demand, requires an operational strategy that makes the system operate properly. This means the system must be able to respond to the building energy demand while having the best performance within the constraints imposed by the operational strategy. When a cogeneration system (combined heating and power) or trigeneration system (combined cooling, heating, and power) operates at partial load, the operational strategy has particular effect on the performance of the system. Two common operational strategies to operate these systems are following the electric load and following the thermal load. This article presents a methodology that allows selecting the right operational strategy based on the ratio between the building electric and thermal loads, and the ratio between electricity demand and size of the power generation unit when exporting electricity is not an option. Results show that the following the thermal load strategy seems to be better than the following the electric load strategy for most cases. Therefore, the methodology presented in this article is a decision-making tool for the selection of the right operational strategy.
Parametric study of a fan-bladed micro-wind turbine
Authors: Leung D Y C , Deng Y , Leung M K H
Published: September 2011

The present paper investigates the performance of a special micro-wind turbine designed to capture wind energy in rural as well as urban environments. Different from traditional kilo- to megawatt size wind turbines which can be connected directly to the grid, the micro-wind turbine system is flexible in size and linked with small generators that generate electric power at the site of installation for easy applications. The main advantage of this micro-wind turbine, apart from its low cost, is that it can be propelled by a wind speed as low as 2 m/s. To extract more wind energy, several such micro-wind turbines can be connected together by their external gears into an array to increase their swept areas and hence power. In the study, the performance of a single micro-wind turbine was simulated using computational fluid dynamics (CFD) and validated through physical experiments. The experimental results on angular velocity and power developed showed a good agreement with those predicted by the CFD simulation. The validated computer model was then used for a parametric study of the wind turbine with varying blade subtend angles and number of blades, both of which affect the torque acting on the wind turbine and the power performance. The design of the wind turbine blade was optimized through the CFD simulation. This paper considers mainly the aerodynamic performance of a single turbine and issues relating to its practical deployment are not dealt with.
Biomass combined cycles based on externally fired gas turbines and organic Rankine expanders
Authors: Invernizzi C M , Iora P , Sandrini R
Published: September 2011

This article investigates the possibility to enhance the performance of a biomass organic Rankine cycle (ORC) plant by adding an externally fired gas turbine (EFGT), yielding a combined EFGT + ORC system. A typical ORC configuration is first modelled and validated on data available from an existing unit 1.5 MW reference plant. Then, different working fluids belonging to the methyl-substituted benzene series and linear methylpolysiloxanes have been evaluated for the ORC section on the basis of both thermodynamics considerations and design issues of the regenerator and the turbine. Results of the simulations of the combined cycle (CC) referred to a furnace size of about unit 9 MW, assuming a maximum GT inlet temperature of 800 °C, show a maximum efficiency of 23 per cent, obtained in the case where toluene is adopted as a working fluid for the bottoming section. This value is about 4 points per cent higher than the efficiency of the corresponding simple ORC. Finally, to conclude, some preliminary considerations are given regarding the techno-economic feasibility of the combined configuration, suggesting the need of a further investigation on the possible technological solution for the furnace which represents the main uncertainty in the resulting costs of the CC.
Output feedback control of constrained descriptor systems: a case study of a hydraulic tank system
Authors: Araújo J M , Barroso H C , Barros P R , Dórea C E T
Published: September 2011

A novel technique is proposed for output feedback control of constrained linear discrete-time causal descriptor systems. In particular, it is shown how linear state and control constraints can be satisfied by using only output measurements corrupted by unknown but bounded noise. To this end, conditions are established under which a polyhedron contained in the set defined by the state constraints can be made invariant through output feedback. The control input which enforces the constraints can be computed online through the solution of linear programming problems. The proposed technique is then applied to the control of a hydraulic three-tank system. Simulated as well as experimental results illustrate the proposed technique and indicate that it can be potentially used in practical situations.
A multi-state model for the analysis of changes in cognitive scores over a fixed time interval
Authors: Mitnitski Arnold B , Fallah Nader , Dean Charmaine B , Rockwood Kenneth
Published: September 2011

In this article, we present the novel approach of using a multi-state model to describe longitudinal changes in cognitive test scores. Scores are modelled according to a truncated Poisson distribution, conditional on survival to a fixed endpoint, with the Poisson mean dependent upon the baseline score and covariates. The model provides a unified treatment of the distribution of cognitive scores, taking into account baseline scores and survival. It offers a simple framework for the simultaneous estimation of the effect of covariates modulating these distributions, over different baseline scores. A distinguishing feature is that this approach permits estimation of the probabilities of transitions in different directions: improvements, declines and death. The basic model is characterised by four parameters, two of which represent cognitive transitions in survivors, both for individuals with no cognitive errors at baseline and for those with non-zero errors, within the range of test scores. The two other parameters represent corresponding likelihoods of death. The model is applied to an analysis of data from the Canadian Study of Health and Aging (1991–2001) to identify the risk of death, and of changes in cognitive function as assessed by errors in the Modified Mini-Mental State Examination. The model performance is compared with more conventional approaches, such as multivariate linear and polytomous regressions. This model can also be readily applied to a wide variety of other cognitive test scores and phenomena which change with age.
Efficient design of cluster randomized and multicentre trials with unknown intraclass correlation
Authors: van Breukelen Gerard JP , Candel Math JJM
Published: September 2011

For cluster randomized and multicentre trials evaluating the effect of a treatment on persons nested within clusters, equations have been published to compute the optimal sample sizes at the cluster and person level as a function of sampling costs and intraclass correlation ( ICC). Here, optimal means maximum power and precision for a given sampling budget, or minimum sampling costs for a given power and precision. However, the ICC is usually unknown, and the optimal sample sizes depend strongly on this ICC. To overcome this local optimality problem, this study presents Maximin designs (MMDs) based on relative efficiency (RE) and efficiency. These designs perform well over a range of possible ICC values either in terms of RE compared with the locally optimal designs, or in terms of minimum efficiency (maximum variance) of the treatment effect estimator. The use of MMDs is illustrated using information from many cluster randomized trials in primary care. It is concluded that MMDs and the optimal design for an ICC halfway its assumed range are efficient for a range of ICC values and recommendable for practical use. This requires that trial reports mention the study cost per cluster and person.
Design and Performance Evaluation of MR Damper for Integrated Isolation Mount
Authors: Seong Min-Sang , Choi Seung-Bok , Kim Cheol-Ho
Published: September 2011

This article presents a new type of a MR damper designed for an integrated isolation mount for an ultraprecision manufacturing system. The vibration sources of the ultraprecision system can be classified as two: one is environmental vibration from the floor, and the other is transient vibration occurred from the stage movement. The transient vibration occurred from the stage movement has adverse effect to the manufacturing process because the vibration scale is quite larger than other vibrations. It is also known that the moving stage needs to be isolated from tiny vibrations to be occurred from the floor. Therefore, in this research in order to attenuate both the transient and tiny vibrations, a new type of MR damper is proposed and its performance is evaluated. The proposed MR damper can eliminate a dry friction of the damper to remove the tiny vibration as well as can produce enough damping force to attenuate the transient vibration. The MR damper is designed on the basis of Bingham model of a MR fluid and manufactured. Subsequently, the field-dependent damping force characteristics of the MR damper are evaluated through simulation and experiment. In addition, vibration control performance of the proposed MR damper is evaluated by integrating the damper with a 2 degree of freedom (DOF) stage model. In this evaluation, both transient and sinusoidal vibrations are controlled by adopting both a skyhook controller and a sliding mode controller.
Design and experimental characterization of an electromagnetic transducer for large-scale vibratory energy harvesting applications
Authors: Cassidy Ian L. , Scruggs Jeffrey T. , Behrens Sam , Gavin Henri P.
Published: September 2011

This article reports on the design and experimental characterization of an electromagnetic transducer for energy harvesting from large structures (e.g., multistory buildings and bridges), for which the power levels can be above 100 W and disturbance frequencies below 1 Hz. The transducer consists of a back-driven ballscrew coupled to a permanent-magnet synchronous machine with power harvesting regulated via control of a four-quadrant power electronic drive. Design considerations between various subsystems are illustrated and recommendations in terms of minimal values are made for each design metric. Developing control algorithms to take full advantage of the unique features of this type of transducer requires a mechanical model that can adequately characterize the device’s intrinsic nonlinear behavior. A new model is proposed that can effectively capture this behavior. Comparison with experimental results verifies that the model is accurate over a wide range of operating conditions. As such, the model can be used to assess the viability of the technology and to correctly design controllers to maximize power generation. To demonstrate the device’s energy harvesting capability, impedance matching theory is used to optimize the power generated from a base-excited tuned mass damper. Both theoretical and experimental investigations are compared and the results are shown to match closely.
Experimental investigations of surface wear assessment of spur gear teeth
Authors: Amarnath Muniyappa , Chandramohan Sujatha , Seetharaman Swarnamani
Published: September 2011

The most common gear wear mechanisms, such as micropitting, pitting and scouring often occur in the early stage of failure. For the geared system operating in the presence of such surface failures, the load acts only over a finite region and contact stress tends to increase enormously in the contact area of the mating teeth surface. The propagation of tooth damage causes instantaneous reduction in tooth stiffness. The vibration signal of gear transmission varies as the stiffness changes. Therefore the connection between surface fatigue failure, stiffness and vibration signal are of significant importance in monitoring gear defects. The purpose of this study is to conduct experimental investigations on the measurement of reduction in the gear teeth stiffness along with vibrations parameters. A pair of spur gears was tested under an accelerated test condition in an oil bath lubricated back-to-back gearbox. Experimental measurement of stiffness was carried out using modal analysis in conjunction with a theoretical model. It is concluded that stiffness measurement exhibits a direct relationship with the propagation of surface wear and the increase in vibration amplitude of the gear transmission system. Hence this procedure can be concluded as a suitable technique in health monitoring of gears.
Iterated schemes for dynamic condensation of structures with general viscous damping distributions
Authors: Liu Zheng-Shan , Wu Zhi-Gang
Published: September 2011

Two iterated schemes for dynamic condensation of finite element models with general viscous damping in the displacement space are presented in this paper. The conventional techniques are often defined in the state space to reckon-in the effect of damping on the transformation matrix. However, much more computational resources are required to accomplish the model reduction while the size of system matrices is doubled from displacement space to state space, especially for large-scale models. This problem can be overcome by the new reduction schemes defined in the displacement space. In addition to the remarkable improvement of computational efficiency, the explicit forms of reduced mass, damping and stiffness matrices can also be directly obtained by the newly developed method, which fully takes into account the damping in the transformation matrix. Two numerical examples are carried out to demonstrate the effectiveness of the proposed dynamic condensation schemes.
Discretization effects on flutter aspects and control of wing/store configurations
Authors: Nayfeh AH , Hammad BK , Hajj MR
Published: September 2011

Two discretization approaches are considered for the prediction of the flutter characteristics of the Goland+ wing with a store. In one approach, referred to as an uncoupled-mode approach, the common notion that neglects the store when generating the basis functions is considered. This approach results in uncoupled mode shapes of the bending and torsion motions. In the second approach, referred to as semi-coupled-mode approach, coupling between the bending and torsion motions due to the shear force and moment exerted by the store at the tip of the wing are taken into account. It is found that the two approaches yield different instability parameters and characteristics. Through comparison with the exact solution, it is found that the semi-coupled-mode approach correctly predicts the natural frequencies of the wing/store system and the speed and type of the instability, whereas the uncoupled-mode approach fails to predict the natural frequencies of the structure, overestimates the instability speed, and fails to predict the type of instability. The usefulness of a physics-based discretization approach used to assess control schemes and effects of gains on the flutter speed and type of instability is demonstrated.
A method based on the tau approach for the identification of a time-dependent coefficient in the heat equation subject to an extra measurement
Authors: Saadatmandi Abbas , Dehghan Mehdi
Published: September 2011

In this work, the problem of parameter identification in a parabolic partial differential equation is discussed. The shifted Legendre-tau method is presented for finding the unknown function and also the unknown coefficient in the one-dimensional diffusion model. The method consists of expanding the required approximate solution as the elements of a shifted Legendre polynomial and by using operational matrices we reduce the problem to a set of algebraic equations. Several examples are given to demonstrate the validity and applicability of the technique and a comparison is made with existing results. The method is easy to implement and yields very accurate results.
A solution to the flexible transmission benchmark by convex optimization
Authors: Galdos Gorka , Karimi Alireza
Published: September 2011

The flexible transmission benchmark was proposed in the European Journal of Control to evaluate some robust digital control approaches in 1995. With progress in convex optimization algorithms, new methods for robust controller design have been developed. A recently proposed fixed-order robust controller design method is applied to this benchmark problem and the results are compared with the existing results. The proposed method is based on open-loop shaping with frequency-domain constraints on the closed-loop sensitivity functions in the Nyquist diagram. The method needs only the frequency response of the model and can consider the multimodel uncertainty. A controller is designed by a convex optimization algorithm that meets all of the required performance specifications for the benchmark with the lowest controller complexity.