bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparing simple root phenotyping methods on a core set of rice genotypes
Authors: Shrestha R. , Al‐Shugeairy Z. , Al‐Ogaidi F. , Munasinghe M. , Radermacher M. , Vandenhirtz J. , Price A. H.
Published: September 2013

Interest in belowground plant growth is increasing, especially in relation to arguments that shallow‐rooted cultivars are efficient at exploiting soil phosphorus while deep‐rooted ones will access water at depth. However, methods for assessing roots in large numbers of plants are diverse and direct comparisons of methods are rare. Three methods for measuring root growth traits were evaluated for utility in discriminating rice cultivars: soil‐filled rhizotrons, hydroponics and soil‐filled pots whose bottom was sealed with a non‐woven fabric (a potential method for assessing root penetration ability). A set of 38 rice genotypes including the OryzaSNP set of 20 cultivars, additional parents of mapping populations and products of marker‐assisted selection for root QTLs were assessed. A novel method of image analysis for assessing rooting angles from rhizotron photographs was employed. The non‐woven fabric was the easiest yet least discriminatory method, while the rhizotron was highly discriminatory and allowed the most traits to be measured but required more than three times the labour of the other methods. The hydroponics was both easy and discriminatory, allowed temporal measurements, but is most likely to suffer from artefacts. Image analysis of rhizotrons compared favourably to manual methods for discriminating between cultivars. Previous observations that cultivars from the indica subpopulation have shallower rooting angles than aus or japonica cultivars were confirmed in the rhizotrons, and indica and temperate japonicas had lower maximum root lengths in rhizotrons and hydroponics. It is concluded that rhizotrons are the preferred method for root screening, particularly since root angles can be assessed.
Microgravity effects on different stages of higher plant life cycle and completion of the seed‐to‐seed cycle
Authors: De Micco V. , De Pascale S. , Paradiso R. , Aronne G.
Published: September 2013

Human inhabitation of Space requires the efficient realisation of crop cultivation in bioregenerative life‐support systems (BLSS). It is well known that plants can grow under Space conditions; however, perturbations of many biological phenomena have been highlighted due to the effect of altered gravity and its possible interactions with other factors. The mechanisms priming plant responses to Space factors, as well as the consequences of such alterations on crop productivity, have not been completely elucidated. These perturbations can occur at different stages of plant life and are potentially responsible for failure of the completion of the seed‐to‐seed cycle. After brief consideration of the main constraints found in the most recent experiments aiming to produce seeds in Space, we focus on two developmental phases in which the plant life cycle can be interrupted more easily than in others also on Earth. The first regards seedling development and establishment; we discuss reasons for slow development at the seedling stage that often occurs under microgravity conditions and can reduce successful establishment. The second stage comprises gametogenesis and pollination; we focus on male gamete formation, also identifying potential constraints to subsequent fertilisation. We finally highlight how similar alterations at cytological level can not only be common to different processes occurring at different life stages, but can be primed by different stress factors; such alterations can be interpreted within the model of ‘stress‐induced morphogenic response’ (SIMR). We conclude by suggesting that a systematic analysis of all growth and reproductive phases during the plant life cycle is needed to optimise resource use in plant‐based BLSS.
Behind the scenes: How visual memory load biases selective attention during processing of visual streams
Authors: Klaver Peter , Talsma Durk
Published: September 2013

We recorded ERPs to investigate whether the visual memory load can bias visual selective attention. Participants memorized one or four letters and then responded to memory‐matching letters presented in a relevant color while ignoring distractor letters or letters in an irrelevant color. Stimuli in the relevant color elicited larger frontal selection positivities (FSP) and occipital selection negativities (OSN) compared to irrelevant color stimuli. Only distractors elicited a larger FSP in the high than in the low memory load task. Memory load prolonged the OSN for all letters. Response mapping complexity was also modulated but did not affect the FSP and OSN. Together, the FSP data suggest that high memory load increased distractability. The OSN data suggest that memory load sustained attention to letters in a relevant color until working memory processing was completed, independently of whether the letters were in working memory or not.
Sleep duration and cardiovascular responses to stress in undergraduate men
Authors: Mezick Elizabeth J. , Matthews Karen A. , Hall Martica H. , Richard Jennings J. , Kamarck Thomas W.
Published: September 2013

Short sleep has been related to incident cardiovascular disease, but physiological mechanisms accounting for this relationship are largely unknown. This study examines sleep duration and cardiovascular stress responses in 79 healthy, young men. Sleep duration was assessed by wrist actigraphy for seven nights. Participants then completed a series of laboratory stress tasks while heart rate and blood pressure were monitored. Shorter total sleep time was related to a greater reduction in high‐frequency heart rate variability during stress tasks, and to prolonged elevations in heart rate and diastolic pressure following tasks. Associations were independent of age, race, body mass index, caffeine intake, and smoking status. In sum, healthy young men with shorter actigraphy‐assessed sleep exhibit less cardiac vagal activity, and poorer heart rate and diastolic blood pressure recovery, upon encountering stressful stimuli, than those with longer sleep.
How does firm experience and institutional distance impact ownership choice in high‐technology acquisitions?
Authors: Elango B. , Lahiri Somnath , Kundu Sumit K.
Published: September 2013

One of the critical reasons for a firm to acquire other firms is to access new technology. This study seeks to understand what ownership position a firm should take in foreign markets if the target is in a high‐technology industry. Specifically, it looks at how firm‐level experience and institutional distance could impact this ownership. Using logistic regression models on a sample of 1,091 cross‐border acquisitions undertaken by firms from 36 countries over an 8‐year time period (2001–2008), we find that when firms acquire targets in a high‐technology industry, they resort to partial acquisitions. Our analysis further suggests that when firms seek targets in high‐technology industries but have experience with acquisitions or face higher institutional distance, the likelihood of full acquisitions over partial ones increases. Study findings contribute to our understanding of the interactive relationship among technology, experience, and institutional distance in determining appropriate ownership choices.
Stimulating Natural Regeneration of Tropical Forest on Degraded Land: Approaches, Outcomes, and Information Gaps
Authors: Shoo Luke P. , Catterall Carla P.
Published: September 2013

Extensive land clearing in many parts of the global tropics is a major threat to biodiversity, and strategies are urgently needed to reinstate forest. Tree planting is a commonly used strategy to rapidly restore forest to degraded landscapes. However, tree planting is expensive, and in most cases financial constraints prevent its use at a scale needed to address the ongoing legacy of land clearing. Here, we conduct a quantitative review of literature from the global tropics and evaluate outcomes of less intensive interventions (i.e. non‐planting) aimed at stimulating natural regeneration of forest. We focus specifically on overcoming barriers to native plant regeneration that predominate in the earliest stages of succession. Common interventions include varied strategies to suppress herbaceous vegetation (e.g. cutting or herbicide treatment), and measures to bolster propagule supply (e.g. direct seeding and artificial bird perches). There was an apparent trend among pair‐wise comparisons of effect sizes to suggest that combined interventions to simultaneously suppress herbaceous vegetation and increase propagule supply resulted in the most consistent outcomes in terms of promoting progress toward restoring forest structure. Despite an obvious demand for lower cost interventions, a paucity of information means that it is still premature to generalize outcomes of specific interventions and their overall cost relative to active tree planting. Nevertheless, we report an increase in research effort in this area, and suggest promising directions to accelerate progress that will improve capacity to select optimal, cost effective strategies that achieve long‐term restoration objectives with a particular level of certainty.
Urban Grassland Restoration: A Neglected Opportunity for Biodiversity Conservation
Authors: Klaus Valentin H.
Published: September 2013

Urbanization is one of the most severe threats to biodiversity, so why should not we use green space in cities to counteract the biodiversity loss as much as possible? Urban grasslands provide a large number of social, financial, recreational, and environmental ecosystem services but can also support high biodiversity. In this article, I describe the importance of urban grasslands for (local) biodiversity and recommend strengthening restoration ecological research and efforts to optimize these novel ecosystems for conservation purposes. The management intensity of a high proportion of urban grasslands decreased over the last decades. However, species richness of these grasslands is still low, although there is now a great potential for higher plant, but also animal diversity. While communal authorities are interested in cost‐efficient but at the same time biodiversity‐friendly management of urban grasslands, a well‐founded scientific basis for the restoration of urban grassland is still missing. I argue that besides all challenges associated with the restoration of urban habitats we should urgently proceed in the development of appropriate and effective restoration approaches and communicate knowledge gained to urban planners and stakeholders. Widening the scope of restoration ecological research to novel ecosystems such as urban grasslands is one of the most important recent challenges for biodiversity restoration and it gives urban habitats the significance they deserve.
Caries risk profile of Korean dental patients with severe intellectual disabilities
Authors: Chang Juhea , Lee Jung‐Hyun , Son Ho‐Hyun , Kim Hae‐Young
Published: September 2013

This study evaluated the caries risk profile of patients with severe intellectual disabilities (IDs) who received dental treatment under general anesthesia. One hundred and two patients with ID [ID group, mean age (SD); 23.8(9.3)] and 100 healthy patients without ID [NID group, mean age (SD); 23.19(3.3)] were included. Medication, disability type, oral hygiene maintenance, and cooperation of the patients were investigated. Dietary habits, plaque index, mutans streptococci counts, fluoride availability, and salivary buffering were scored and analyzed using the Cariogram. The mean chance of avoiding caries (SD) was 28.1(20.4) in the ID group and 54.7(18.4) in the NID group. The ID group had significantly higher numbers of decayed and missing teeth, but fewer filled teeth than the NID group (p < .05). Significant disparities existed in the distributions of all caries‐related factors except for mutans streptococci counts between the two groups (p < .05). The low chance to avoid future caries in ID patients was closely associated with insufficient oral hygiene maintenance (p < .05). Fluoride availability was strongly associated with the chance of avoiding caries in the ID group. Dental patients with severe ID exhibited a higher risk of developing caries than normal patients. Among several caries‐related factors, insufficient oral hygiene maintenance and low fluoride availability most contributed to the high risk.
Do Ketoanalogues Still Have a Role in Delaying Dialysis Initiation in CKD Predialysis Patients?
Authors: Aparicio Michel , Bellizzi Vincenzo , Chauveau Philippe , Cupisti Adamasco , Ecder Tevfik , Fouque Denis , Garneata Liliana , Lin Shanyan , Mitch William , Teplan Vladimir , Yu Xueqing , Zakar Gabor
Published: September 2013

Early versus later start of dialysis is still a matter of debate. Low‐protein diets have been used for many decades to delay dialysis initiation. Protein‐restricted diets (0.3–0.6 g protein/kg/day) supplemented with essential amino acids and ketoanalogues (sVLPD) can be offered, in association with pharmacological treatment, to motivated stage 4–5 chronic kidney disease (CKD) patients not having severe comorbid conditions; they probably represent 30–40% of the concerned population. A satisfactory adherence to such dietary prescription is observed in approximately 50% of the patients. While the results of the studies on the effects of this diet on the rate of progression of renal failure remain inconclusive, they are highly significant when initiation of dialysis is the primary outcome. The correction of uremic symptoms allows for initiation of dialysis treatment at a level of residual renal function lower than that usually recommended. Most of the CKD‐associated complications of cardiovascular and metabolic origin, which hamper both lifespan and quality of life, are positively influenced by the diet. Lastly, with regular monitoring jointly assumed by physicians and dietitians, nutritional status is well preserved as confirmed by a very low mortality rate and by the absence of detrimental effect on the long‐term outcome of patients once renal replacement therapy is initiated. On account of its feasibility, efficacy and safety, sVLPD deserves a place in the management of selected patients to safely delay the time needed for dialysis.
Selective serotonin reuptake inhibitor (SSRI) toxicosis in cats: 33 cases (2004–2010)
Authors: Pugh Cassandra M. , Sweeney Joseph T. , Bloch Christopher P. , Lee Justine A. , Johnson Justine A. , Hovda Lynn R.
Published: September 2013

Objective

To evaluate a population of cats with selective‐serotonin reuptake inhibitor (SSRI) toxicosis and characterize the population affected, list products ingested, the clinical signs observed, treatments performed, length of hospitalization, patient outcome, and overall prognosis.

Design

Retrospective study from 2004 to 2010.

Setting

Referral veterinary center.

Animals

Thirty‐three witnessed cat SSRI ingestions.

Interventions

None.

Measurements and Main Results

The medical records of cats with a witnessed SSRI ingestion identified by review of an animal poison control center electronic database were evaluated. The most common SSRIs ingested were venlafaxine (Effexor; 12/33; 36%), fluoxetine (Prozac; 12/33; 36%), citalopram (Celexa; 6/33; 18%), and escitalopram (Lexapro; 3/33; 9%). Overall, 24% of cats (8/33) became symptomatic, while 76% (25/33) remained asymptomatic. Of the symptomatic cats, sedation was the most common clinical sign (6/8; 75%), followed by gastrointestinal signs (4/8; 50%), central nervous system stimulation (1/8; 13%), cardiovascular signs (1/8; 13%), and hyperthermia (1/8; 13%). Veterinary care was sought in 20 cats (20/33; 61%). Sixteen cats (16/20; 80%) were hospitalized, while 4 cats (4/20; 20%) were treated as outpatients. Treatment for hospitalized patients included administration of IV fluid therapy (14/16; 88%), activated charcoal (12/16; 75%), anti‐arrhythmic agents (7/16; 44%), methocarbamol (6/16; 38%), cyproheptadine (6/16; 38%), anti‐emetics (5/16; 31%), and sedation (5/16; 31%). Diagnostics included blood work (7/16; 44%), blood pressure measurement (3/16; 19%), and electrocardiogram monitoring (2/16; 13%). Mean hospitalization time for all cases of SSRI ingestion was 14.6 ± 7.8 hours (n = 16). All symptomatic cats in this study (8/8; 100%) had resolution of clinical signs and survived to discharge.

Conclusions

The prognosis for SSRI ingestion in this population of cats was excellent. Decontamination and supportive care for at least 12–24 hours can be considered in cats with SSRI ingestion, particularly venlafaxine to monitor resolution of clinical signs.
Positive impact of an emergency department protocol on time to antimicrobial administration in dogs with septic peritonitis
Authors: Abelson Amanda L. , Buckley Gareth J. , Rozanski Elizabeth A.
Published: September 2013

Objective

To determine whether the development of a specific antimicrobial protocol for the treatment of canine intra‐abdominal sepsis would improve time to appropriate antimicrobial administration following diagnosis of bacterial peritonitis.

Design

Case controlled observational study.

Setting

A tertiary referral small animal teaching hospital.

Animals

Twenty dogs undergoing surgery for septic peritonitis prior to the deployment of the abdominal sepsis protocol served as a case control population and 40 dogs identified as having septic peritonitis after deployment of the protocol served as the study population.

Interventions

None.

Measurements and Main Results

Median time from diagnosis of septic peritonitis to antimicrobial administration was 6 hours (range 1–10 h) in the preprotocol group (PRE), and 1 hour (range 1–2 h) in the postprotocol group (POST) (P= 0.001). Five of 20 (25%) culture and sensitivity results yielded negative cultures in the PRE versus 6 of 34 (17.6%) in the POST. Inappropriate empirical antimicrobials were selected 3 of 20 times (15%) in the PRE and 3 of 34 times (8.8%) in the POST. The overall survival to discharge was 60% in the PRE and 70% in the POST (P= 0.425).

Conclusions

The development of an emergency department antimicrobial protocol significantly decreased time to antimicrobial administration following identification of septic peritonitis in dogs.
Comparative seed predation of woolly cupgrass (Eriochloa villosa) and yellow foxtail (Setaria pumila) along a field border in Canada
Authors: Simard Marie‐Josée , Darbyshire Stephen J. , Nurse Robert E.
Published: September 2013

The seed predation of woolly cupgrass (Eriochloa villosa), an invasive weed of East‐Asian origin, was compared to that of yellow foxtail (Setaria pumila), an established and widespread weed, along a field border in Canada. The seeds of both species were glued to sandpaper cards and their removal in field conditions was recorded from July to September during the 3 years of 2009, 2010 and 2011. Predator exclusion cages allowed the evaluation of seed loss to be attributed to invertebrates, vertebrates and total seed loss due to predation for both species. Pitfall traps were installed and collected once in 2010 and during all the seed sampling dates in 2011 in order to evaluate predatory pressure from ground beetles and crickets. The average amount of seed loss that could be attributed to invertebrates was higher for S. pumila than for E. villosa, while the amount of seed loss that could be attributed to vertebrates was higher for E. villosa than for S. pumila in 2009 and 2010. The level of S. pumila seed loss to invertebrates was correlated with the sum of crickets (Gryllus pennsylvanicus) and beetles (Harpalus spp. and Ophonus rufibarbis) trapped during the 2011 season. During the same period, correlations between E. villosa seed loss to invertebrates and trapped insects were not observed. Reduced postdispersal seed predation by invertebrates could increase the local fall survival of the unburied seeds of invasive E. villosa populations, compared to other naturalized, smaller‐seeded weedy grasses.
Density-Based Decline Performance Analysis of Natural Gas Reservoirs Using a Universal Type Curve
Authors: H. Luis F. Ayala , Ye Peng
Published: September 2013

Modern natural gas reservoir decline performance analysis has traditionally relied on the use of oil type curves along with the concepts of pseudopressure and pseudotime. Alternatively, it also employs empirical curve fitting of rate-time production data for reserve and future performance analysis. In this work we show that the use of a density approach leads to the formulation of a new-generation type curve applicable to the analysis of unsteady state of natural gas wells under boundary dominated flow (BDF). The resulting gas reservoir decline equation applies to any gas well producing at constant bottomhole pressure under BDF. On the basis of this decline model, a single-line, universal type curve is derived for any gas fluid and reservoir properties producing under a constant drawdown condition. New-generation analytical procedures for gas well performance analysis are presented, which does not necessitate the calculation of pseudopressure or pseudotime. Explicit OGIP predictions are thus enabled from the proposed universal type curve matching. The proposed single-line type curve is demonstrated to successfully match rate-time production BDF data and reliably estimate fluids in place for a number of numerical simulations and field cases. It is also demonstrated that the proposed formulation can be alternatively implemented in terms of straight-line analysis of 1/qgscb versus time data plots.
Particle Manipulation in Insulator Based Dielectrophoretic Devices1
Authors: Gencoglu Aytug , Olney David , LaLonde Alexandra , Koppula Karuna S. , Lapizco-Encinas Blanca H.
Published: September 2013

Microfluidic devices can make a significant impact in many fields where obtaining a rapid response is critical, particularly in analyses involving biological particles, from deoxyribonucleic acid (DNA) and proteins, to cells. Microfluidics has revolutionized the manner in which many different assessments/processes are carried out, since it offers attractive advantages over traditional bench-scale techniques. Some of the advantages are: small sample and reagent amounts, higher resolution and sensitivity, improved level of integration and automation, lower cost and much shorter processing times. There is a growing interest on the development of techniques that can be used in microfluidics devices. Among these, electrokinetic techniques have shown great potential due to their flexibility. Dielectrophoresis (DEP) is an electrokinetic mechanism that refers to the interaction of a dielectric particle with a spatially non-uniform electric field; this leads to particle movement due to polarization effects. DEP offers great potential since it can be carried out employing DC and AC electric fields, and neutral and charged particles can be manipulated. This work is focused on the use of insulator based dielectrophoresis (iDEP), a novel dielectrophoretic mode that employs arrays of insulating structures to generate dielectrophoretic forces. Successful micro and nanoparticles manipulation can be achieved employing iDEP, due to its unique characteristics that allow for great flexibility. In this work, microchannels containing arrays of cylindrical insulating posts were employed to concentrate, sort and separate microparticles. Mathematical modeling with COMSOL® was performed to identify optimal device configuration. Different sets of experiments were carried out employing DC and AC potentials. The results demonstrated that effective and fast particle manipulation is possible by fine tuning dielectrophoretic force and electroosmotic flow.
Adaptive Neural Fuzzy Inference (ANFI) Modeling Technique for Production of Marine Biosurfactant
Authors: Abbasi Ali A. , Ahmadian M. T.
Published: September 2013

In this study; a Sugeno type ANFI model which describes the relationship between the bio surfactant concentration as a model output and the critical medium components as its inputs has been constructed. The critical medium components are glucose, urea, SrCl2 and MgSo4. The experimental data for training and testing capability of the model obtained by a statistical experimental design which have been captured from literatures. Six generalized bell shaped membership function have been selected for each of input variables and based on the training data ANFI model has been trained using the hybrid learning algorithm. The yielded biosurfactant concentration values from the model prediction shows close agreement with the experimental data.
Using Modular Abstract Prototypes as Evolving Research Means in Design Inclusive Research
Authors: Horváth Imre , Du Bois Els
Published: September 2013

Various manifestations of products, prototypes and tools are commonly used in design research to discover and describe novel phenomena, or to test specific research theories, or to explore intrinsic data that cannot be accessed and validated otherwise. However, as research means, the above physical artifacts are over-detailed and inflexible, in particular when phenomena associated with design creativity and product ideation are investigated. To support design inclusive research in the context of conceptualization and early testing of complex, knowledge-intensive software tools, the authors propose modular abstract prototyping. The original goal of abstract prototyping was to demonstrate the real life processes established by new artifact-service combinations, as well as the interactions of humans with them in various application scenarios. A modular abstract prototype relies on a comprehensive information structure. The demonstration contents of the modules are defined by a stakeholder and purpose oriented logical dissecting of this information structure, and implemented as digitally recorded, multi-media enabled narrations and enactments. This paper discusses the technical aspects of developing modular abstract prototypes, and their use as flexible and evolving research means. A complex application example is presented in which modular abstract prototyping was used in focus group sessions to assess the conceptualization of a trade-off forecasting software tool by various stakeholders. This tool is being developed for forecasting energy saving and financial benefits that can be achieved by ubiquitous augmentation. The stakeholders have formulated positive opinion about the level of immersion and the articulation of informing that can be achieved by using modular abstract prototypes. Future research focuses on the development of a web-hosted engine for real-time interactive abstract prototyping in participatory research sessions.
Optimal Design of a Helmholtz Resonator With a Flexible End Plate
Authors: Kurdi Mohammad H. , Duncan G. Scott , Nudehi Shahin S.
Published: September 2013

A multi-objective optimization formulation to design a Helmholtz resonator with a flexible end plate is studied. The optimization formulation generates a Pareto curve of design solutions that quantify the trade-off between the optimization goals: minimum resonator volume and maximum transmission loss across a specified frequency range. The optimization problem is formulated and solved in the following manner. First, a mathematical formulation for the transmission loss of the Helmholtz resonator with a flexible plate is completed based on the design parameters. Then, the weighted transmission loss across a specified frequency range and a minimum resonator volume are defined as optimization objectives. Finally, the Pareto curve of optimum design solutions is calculated using a gradient-based approach via the ε-constraint method. The optimization results allow the designer to select resonator design parameters that meet the requirements for both transmission loss and resonator volume. To validate the optimization results, one optimal Helmholtz resonator is manufactured and experimentally confirmed.
Improved Clustering Algorithm for Design Structure Matrix
Authors: Borjesson Fredrik , Hölttä-Otto Katja
Published: September 2013

For clustering a large Design Structure Matrix (DSM), computerized algorithms are necessary. A common algorithm by Thebeau uses stochastic hill-climbing to avoid local optima. The output of the algorithm is stochastic, and to be certain a very good clustering solution has been obtained, it may be necessary to run the algorithm thousands of times. To make this feasible in practice, the algorithm must be computationally efficient. Two algorithmic improvements are presented. Together they improve the quality of the results obtained and increase speed significantly for normal clustering problems. The proposed new algorithm is applied to a cordless handheld vacuum cleaner.
Normalized Evaluation of Fuel Economy for Electric Oriented Commercial Vehicles
Authors: Song Xubin , Liu Jason
Published: September 2013

The fuel economy regulation has been applied to cars and light trucks with a gross vehicle weight rating (GVWR) of 8,500 pounds or less for decades. For the first time, the government is also beginning to work on national mileage standards beyond the existing emission regulation for big rigs and work trucks (i.e., commercial vehicles). This effort will lead to limiting the disproportionate share of pollutions from these large vehicles. The same technology trend for both currently regulated vehicles and those unregulated big trucks is electrification for better energy efficiency. Vehicle electrification will be widely employed to improve energy utilization efficiency, and reduce or even eliminate GHG emissions. Overall the fundamental objective is to reduce the total amount of energy used by vehicles while minimizing the negative environmental impacts overall. Thus, it is critically important to find out an effective and implementable matrix that can be acceptable and recognizable for both industry and public. In this paper, the weight ratio between payload and unloaded vehicle weight is introduced to normalize the conventional mpg to evaluate vehicle performance per duty cycles. This methodology is especially suited to new energy vehicles by using both endogenous fuel and exogenous electricity (if applicable).
Coupled Bending and Torsion Effects on the Squeezed Film Air Damping in Torsional Micromirrors
Authors: Moeenfard Hamid , Kaji Farzaneh , Ahmadian Mohammad Taghi
Published: September 2013

The current paper presents an analytical model for the problem of squeezed film damping in micromirrors considering the bending of the supporting torsion microbeams. At the first the nonlinear Reynolds equation governing the behavior of the squeezed gas underneath the mirror is linearized. The resulting linearized equation is then nondimensionalized and analytically solved for two cases of the infinitesimal and finite tiling angle of the mirror. The obtained pressure distribution from the solution of the Reynolds equation is then utilized for finding the squeezed film damping force and torque applied to the mirror. The results show that in the case of the infinitesimal tilting angle, the squeezed film damping can be modeled with a linear viscous damping in both torsional and lateral directions. It is also shown that when the mirror’s rotation angle is small, with increasing the length of the mirror, the damping force and damping torque are increased. For the case of the finite tilting angle it was observed that the applied damping torque highly depends on the tilting angle of the mirror as well as the ratio of its vertical to angular velocity and as a result the effect of the vertical velocity of the mirror on the squeezed film damping force and torque applied to the mirror cannot be simply neglected. The results of this paper can be used for accurate dynamical modeling of the micromirrors under the effect of the squeezed film damping.
A Reliability Approach to Inverse Simulation Under Uncertainty
Authors: Du Xiaoping
Published: September 2013

Inverse simulation is an inverse process of a direct simulation. During the process, the simulation input variables are identified for a given set of simulation output variables. Uncertainties such as random parameters may exist in engineering applications of inverse simulation. A reliability method is developed in this work to estimate the probability distributions of unknown simulation input. The First Order Reliability Method is employed and modified so that the inverse simulation is embedded within the reliability analysis algorithm. This treatment avoids the separate executions of reliability analysis and inverse simulation and consequently maintains high efficiency. In addition, the means and standard deviations of unknown input variables can also be obtained. A particle impact problem is presented to demonstrate the proposed method for inverse simulation under uncertainty.
Time-Dependent Reliability Analysis by a Sampling Approach to Extreme Values of Stochastic Processes
Authors: Hu Zhen , Du Xiaoping
Published: September 2013

Maintaining high accuracy and efficiency is a challenging issue in time-dependent reliability analysis. In this work, an accurate and efficient method is proposed for limit-state functions with the following features: The limit-state function is implicit with respect to time, and its input contains stochastic processes; the stochastic processes include only general strength and stress variables, or the limit-state function is monotonic to these stochastic processes. The new method employs random sampling approaches to estimate the distributions of the extreme values of the stochastic processes. The extreme values are then used to replace the corresponding stochastic processes, and consequently the time-dependent reliability analysis is converted into its time-invariant counterpart. The commonly used time-invariant reliability method, the First Order Reliability Method, is then applied for the time-variant reliability analysis. The results show that the proposed method significantly improves the accuracy and efficiency of time-dependent reliability analysis.
Sequential Quadratic Programming for Robust Optimization With Interval Uncertainty
Authors: Zhou Jianhua , Cheng Shuo , Li Mian
Published: September 2013

Uncertainty plays a critical role in engineering design as even a small amount of uncertainty could make an optimal design solution infeasible. The goal of robust optimization is to find a solution that is both optimal and insensitive to uncertainty that may exist in parameters and design variables. In this paper, a novel approach, Sequential Quadratic Programing for Robust Optimization (SQP-RO), is proposed to solve single-objective continuous nonlinear optimization problems with interval uncertainty in parameters and design variables. This new SQP-RO is developed based on a classic SQP procedure with additional calculations for constraints on objective robustness, feasibility robustness, or both. The obtained solution is locally optimal and robust. Eight numerical and engineering examples with different levels of complexity are utilized to demonstrate the applicability and efficiency of the proposed SQP-RO with the comparison to its deterministic SQP counterpart and RO approaches using genetic algorithms. The objective and/or feasibility robustness are verified via Monte Carlo simulations.
Amplitude Modulation and Symmetry Breaking Bifurcation in Micro Devices
Authors: Feng Z. C. , Almasri Mahmoud
Published: September 2013

Designs of many micro devices take advantage of the symmetry for better performance, immunity to noise, and for simpler analysis. When a symmetric structure is subjected to symmetric forcing, the symmetric response can become unstable leading to asymmetric responses. The occurrence of symmetry breaking bifurcation leads to complicated dynamic responses which often result in less desirable performances. In this paper, we obtain analytical criteria for the onset of symmetry breaking bifurcations. We also conduct numerical simulations to demonstrate different types of asymmetric dynamic responses resulting from the symmetry breaking bifurcation. In particular, we show the occurrence of amplitude modulated motions in such systems.
A Novel Synthesis Method for Three-Position Motion Generation With Planar Four-Bar Mechanisms
Authors: Han Jianyou , Yang Tong
Published: September 2013

This paper deals with the three-position motion generation problem with two specific grounded link lengths. There are two infinities of solutions for selecting the two links on the derived contours of the link lengths. These points on the contours are circle points or center points. After one half of the basic four bar had been selected on the contour, two infinities of solutions remained. These solutions can be mapped in a plane to determine where the particular types of mechanisms occur. Furthermore after one half of the basic four bar had been selected on the contour, one infinity of solutions still remained on the other contour. This indicates two infinities of solutions are still remained for the two given link lengths. These contours can be displayed in the solution space in which the motion generation is defined. With these significant useful information the better mechanism can be obtained, which satisfies more design conditions. Expressions of the contours are derived. Two numerical examples are used for illustration, but the results can be applied to any three-position motion generation problem.
Analytical Study of Reachable Workspace for 2-RPR Planar Parallel Mechanisms
Authors: Agheli Mahdi , Nestinger Stephen S. , Norton Robert L.
Published: September 2013

In both planar and spatial parallel mechanisms, selection of the structural parameters for a desired workspace generally employs the use of numerical methods. However, using the closed-form solution, if it exists, facilitates workspace-based design and optimization of the mechanism, and may significantly reduce the required time and calculation for finding the workspace of the mechanism. This paper presents a general and comprehensive closed-form solution for the reachable workspace of a 2-RPR planar parallel mechanism. The workspace of the mechanism is analyzed step-by-step in detail and its boundary is derived analytically. Since the solution is closed-form, it has high accuracy and reliability. Furthermore, the provided solution can be employed to solve the workspace of similar mechanisms in a closed-form manner including other n-RPR planar parallel mechanisms.
Refining the Method of Averaging for a More Accurate Analytical Approximation to the Behaviors of a Damped Pendulum
Authors: McGehee Clark C. , Sah Si Mohamed , Mann Brian P.
Published: September 2013

KBM averaging is a widely used technique in the analysis of nonlinear dynamical systems. The KBM method allows complex systems to be approximated as perturbations of simple harmonic oscillator. In many cases, such as in otherwise linear systems with various forms nonlinear damping, the KBM method performs exceptionally well, with error proportional to the size of the perturbations. However, when the largest perturbation in the system arises from nonlinearities in the restoring force, the KBM method falls short, and the interesting effects of other nonlinear terms are drowned out by the approximation errors generated by the KBM method. By generalizing the notion of KBM averaging and approximating systems as perturbations the isoenergy contours of their corresponding Hamiltonian, a greater degree of accuracy can be obtained. We extend the work of several authors to show that not only is this method more accurate, but it is also simple to implement and generalizable to a wide range of nonlinear systems. As an illustrative example, the motion of a pendulum on a tilted platform is studied.
On the Solution of Region-Based Planar Six-Bar Motion Generation for Four Finitely Separated Position
Authors: Han Jianyou , Yang Tong
Published: September 2013

This paper addresses the synthesis problem of Watt-I and Stephenson-IIIa six-bar linkages motion generation for four specified task positions. Both of them have one thing in common — theirs floating links which used as end-effectors are connected to a coupler plane of a four-bar linkage. Once the task positions of end-effector are given, we can calculate the corresponding positions of the coupler plane. Then our focus is on the synthesis of a four bar-linkage and the way that a RR chain can be attached to constrain the links of this four-bar linkage. This synthesis problem of four-bar linkage motion generation can be settled by a solution region method. And then we can present an equation of pivot curve that each point on this curve can generate a satisfactory RR chain. A new local solution region that is more practicable is presented by the last numerical example.
Dynamic Behavior Analysis of Vehicle Shimmy System With Consideration of Clearance in Steering Linkage Mechanism
Authors: Lu Jian-Wei , Xin Jia-Yun , Lee Jongkil , Vakakis Alexander F. , Bergman Lawrence A.
Published: September 2013

Dynamic behavior of the vehicle shimmy system with consideration of steering linkage clearance was analyzed. Based on nonlinear dynamic theories, a 4-DOF dynamic model of vehicle shimmy system with consideration of steering linkage clearance was presented. In which, the revolute movement pair of steering linkage with clearance between the steering tie rod and tie rod arm was described based on Hertz model. Numerical analysis on the dynamic response of the vehicle shimmy system with clearance was carried out, and the results were presented with phase plane, Poincaré map, and bifurcation diagram. The dynamic behavior of the vehicle shimmy system with clearance is compared with that without clearance, and the influence of the clearance on the dynamic behavior of the system is discussed, which will provide theoretical basis for attenuation of vehicle shimmy.
The Monitoring and Control of Burners Co-Firing Coal and Biomass
Authors: Valliappan P. , Jagiełło K. , Wilcox S. J.
Published: September 2013

The monitoring and control of combustion systems co-firing coal and biomass is a critical consideration when aiming to increase the proportion of biomass being combusted. This is because it is likely that the combustion will become increasingly unstable as the biomass proportion increases. In order to develop a flame monitoring and control system, flame signal data sets were collected from combustion measurements taken on a 500kW pilot scale combustion test facility. The sensors used were photodiodes with sensitivities in the UV, visible and IR wavelengths. The analysis of these data, identified flame features that can be related to operational parameters such as flame stability, excess air level, NOx and CO emissions. These features were then applied in the development of an intelligent flame monitoring and optimisation system for individual burners based on these low cost sensors. The testing of the monitoring and control system on a pilot scale burner and at full scale are described in this paper.
An Average Facial Color Image Avatar System for the Analysis by Synthesis of Affect Display by Dynamic Facial Color and Expression
Authors: Yamada Takashi , Watanabe Tomio
Published: September 2013

In this study, we focus on the facial expression of a deformed avatar and develop an average facial color image avatar system based on dynamic facial color and expression to facilitate the analysis by synthesis of an affect display. This is achieved by controlling the parameters of a proposed dynamic facial color model and analyzing the extent to which dynamic facial color with emphasized color tones is suitable for the representation of a laugh. The effectiveness of the system is demonstrated by sensory evaluation. The application of this system in emotional interaction could support psychological experiments related to perception and recognition, based on dynamic facial color and expression.
DARwIn-OP Humanoid Robot Kinematics
Authors: Williams Robert L.
Published: September 2013

This paper presents kinematics analysis for the DARwIn-OP (Dynamic Anthropomorphic Robot with Intelligence – Open-Platform) robot. This is a 20-dof humanoid walking robot developed by Virginia Tech, Purdue, and the University of Pennsylvania and marketed by Robotis Inc. The robot version analyzed in this paper is 455 mm tall and has a mass of 2.8 kg. Ohio University has two of these units for robot applications research and teaching.

Presented are a description of DARwIn-OP, the Denavit-Hartenberg Parameters for each serial chain (2-dof head pan/tilt, 3-dof arms, and 6-dof legs), specific length parameters, joint angle limits, plus forward pose kinematics equations and partial inverse pose kinematics solutions, with examples.
Modeling and Experimental Verification of Electromagnetic Energy Harvesting From Plate Structures
Authors: El-Hebeary Mohamed M. R. , Arafa Mustafa H. , Megahed Said M.
Published: September 2013

The focus of the present work is on the design of plate structures for vibration energy harvesting from two closely-spaced modes of vibration. The work is motivated by the quest to design resonators that respond to variable-frequency sources of base motion. The geometry of two-dimensional structures, such as trapezoidal and V-shaped plates, is explored to obtain two closely-spaced harvestable vibration modes to scavenge energy across a broader bandwidth. To this end, an electromagnetic energy harvester in the form of a base excited plate is proposed. The plate carries tip magnets that oscillate past stationary coils to generate power from the first two modes of vibration. The plate dynamic behavior is governed by its geometry and placement of the magnets on its tip. An effort is made to optimize the system configuration so as to control the spacing between the resonance frequencies while efficiently harvesting energy from both modes. Findings of the present work are verified both numerically and experimentally.
Effectiveness Metrics for Ideation: Merging Genealogy Trees and Improving Novelty Metric
Authors: Vargas Hernandez Noe , Okudan Gül E. , Schmidt Linda C.
Published: September 2013

Experiments on engineering design creativity are typically assessed using either process-based (e.g., protocol studies using a coding scheme) or outcome-based approaches (e.g., assessing the ideas generated using a set of metrics). The authors review existing metrics used in outcome-based creativity experiments and analyze their applicability and limitations. In particular, the focus is on a widely used set of metrics for engineering design creativity experiments developed by Shah et al. [17]. These metrics provide robust conceptual definitions for Quality, Novelty and Variety, and various authors use them as a basis for assessment, adapting the metrics to their implementations as needed. Some other authors have proposed modifications to Shah et al.’s metrics as well as improvements. These changes typically address specific implementation issues, and hence, their validity is limited to the experiments at hand. The authors of this paper believe that the detailed implementation of ideation metrics should not only work numerically, but should also be conceptually consistent. Upon discovering previously not discussed issues of these metrics, the authors present modifications to the Shah et al. Novelty and Variety metric implementations. These changes preserve the numerical and conceptual integrity of the original metric forms. Examples from current design engineering creativity experiments are included to better understand the proposed changes to the metrics.