bluuebunny/crossref_metadata_2025 huggingface dataset:
Rigid 3D geometry matching for grasping of known objects in cluttered scenes
Authors: Papazov Chavdar , Haddadin Sami , Parusel Sven , Krieger Kai , Burschka Darius
Published: March 2012

In this paper, we present an efficient 3D object recognition and pose estimation approach for grasping procedures in cluttered and occluded environments. In contrast to common appearance-based approaches, we rely solely on 3D geometry information. Our method is based on a robust geometric descriptor, a hashing technique and an efficient, localized RANSAC-like sampling strategy. We assume that each object is represented by a model consisting of a set of points with corresponding surface normals. Our method simultaneously recognizes multiple model instances and estimates their pose in the scene. A variety of tests shows that the proposed method performs well on noisy, cluttered and unsegmented range scans in which only small parts of the objects are visible. The main procedure of the algorithm has a linear time complexity resulting in a high recognition speed which allows a direct integration of the method into a continuous manipulation task. The experimental validation with a seven-degree-of-freedom Cartesian impedance controlled robot shows how the method can be used for grasping objects from a complex random stack. This application demonstrates how the integration of computer vision and soft-robotics leads to a robotic system capable of acting in unstructured and occluded environments.
Multi-robot three-dimensional coverage of unknown areas
Authors: Renzaglia Alessandro , Doitsidis Lefteris , Martinelli Agostino , Kosmatopoulos Elias B.
Published: March 2012

The problem of deploying a team of flying robots to perform surveillance coverage missions over an unknown terrain of complex and non-convex morphology is presented. In such a mission, the robots attempt to maximize the part of the terrain that is visible while keeping the distance between each point in the terrain and the closest team member as small as possible. A trade-off between these two objectives should be fulfilled given the physical constraints and limitations imposed at the particular application. As the terrain’s morphology is unknown and it can be quite complex and non-convex, standard algorithms are not applicable to the particular problem treated in this paper. To overcome this, a new approach based on the Cognitive-based Adaptive Optimization (CAO) algorithm is proposed and evaluated. A fundamental property of this approach is that it shares the same convergence characteristics as those of constrained gradient-descent algorithms (which require perfect knowledge of the terrain’s morphology and optimize surveillance coverage subject to the constraints the team has to satisfy). Rigorous mathematical arguments and extensive simulations establish that the proposed approach provides a scalable and efficient methodology that incorporates any particular physical constraints and limitations used to navigate the robots into an arrangement that (locally) optimizes surveillance coverage.
Planning to Change the World
Authors: Campbell Heather
Published: March 2012

It is widely accepted that planning operates at the interface of knowledge and action. As an activity concerned with intervening and taking action to realize better place-based outcomes than would be achieved otherwise, one might assume that the better informed such judgments are, the better the resulting outcomes are likely to be. But how does (and should) knowledge about the world get turned into actions designed to make the world a better place? This article develops a framework to examine the intellectual and practical questions at the heart of the relationship between is and ought.
Reducing the inhibitory effect of cigarette smoke on the activity of oral peroxidase by the addition of berberine in cigarette filter
Authors: Wu Jinfeng , Ye Xiaoli , Cui Xuelong , Li Xuegang , Zheng Lifeng , Chen Zhu
Published: March 2012

This study was carried out to evaluate the effect of cigarette smoke (CS) on the activity of oral peroxidase (OPO) after berberine was added to the cigarette filter. Activated carbon fiber (ACF) was chosen to load berberine as a part of the cellulose acetate (CA) filter to obtain the modified B-ACF cigarette filter. Then the effects of CS from the testing cigarettes on the activity of OPO were investigated in vitro by the 2-nitrobenzoic acid assay, and the smoke chemistry was also analyzed, especially the content of hydrogen cyanide (HCN) in the CS. The results indicated that the loss of activity of OPO in B-ACF filter cigarette group decreased by 20% and 25%, compared with those of ACF and CA filter cigarette groups, respectively. The relative residual activity of OPO in B-ACF filter group was increased with the increase of berberine in the filter compared with the CA filter group. It could be observed that the reduction in HCN might be related to the berberine in the cigarette filter, reducing the inhibition of CS on the activity of OPO.
Carbohydrate-based polyamides and polyesters: an overview illustrated with two selected examples
Authors: Muñoz-Guerra Sebastián
Published: March 2012

An overview on the synthesis, structure and properties of polyamides and aromatic copolyesters produced by using monomers derived from carbohydrates is provided. Two examples are selected for illustration: (a) aliphatic polyamides prepared from aldaric acids and (b) aromatic copolyesters containing alditols units. Polycondensation in solution of n-alkanediamines ( n taking even values from 6 to 12) with activated pentaric (l- arabino and xylo) and hexaric ( galacto and d- manno) acids bearing the secondary hydroxyl groups protected as methyl ether, afforded linear polyaldaramides PA- nSu with Mw oscillating between 25 000 and 150 000 g mol−1. They are stable above 300°C and are semicrystalline even so only PA- nMn are stereoregular. Melting temperatures of PA- nSu range between 140 and 230°C and most of them are able to crystallize from the melt at a rate that increases with the length of the polymethylene segment. Both melting and glass transition temperatures decrease with the content in sugar units. Spherulitic films, oriented fibers and lamellar single crystals could be obtained from PA -nSu. All these polyamides seem to adopt a common crystal structure made of hydrogen-bonded sheets with the sugar residue skewed to attain an efficient side-by-side packing of the polymer chains. Aromatic homopolyesters and copolyesters derived from terephthalic acid and mixtures of butylene glycol and O-methylated alditols were prepared by polycondensation in the melt with Mw in the 20 000–50 000 g mol−1 range and a random microstructure. The thermal properties of PBT containing alditols units are very depending on the sugar constitution and copolyester composition. In general they are thermally stable above 300°C and display crystallinity for contents in alditols up to 30%. Melting temperatures decrease with the content in alditols whereas an opposite trend is observed for glass transition temperatures. The crystalline structure of PBT is preserved in the crystalline copolyesters whereas a different crystal lattice is adopted by homopolyesters entirely made of alditol units. In general, polyamides and polyesters containing sugar derived units are widely soluble in organic solvents, markedly hydrophilic and more susceptible to hydrolysis than their parent polymers.
Synthesis, characterization, topographical modification, and surface properties of copoly(imide siloxane)s
Authors: Wohl Christopher J. , Atkins Brad M. , Belcher Marcus A. , Connell John W.
Published: March 2012

Novel copoly(imide siloxane)s were synthesized from commercially available aminopropyl terminated siloxane oligomers, aromatic dianhydrides, and diamines. This synthetic approach produced copolymers with well-defined siloxane blocks linked with imide units in a random fashion. The copoly(amide acid)s were characterized by solution viscosity and subsequently used to cast thin films followed by thermal imidization in an inert atmosphere. Thin films were characterized using contact angle goniometry, attenuated total reflection Fourier transform infrared spectroscopy, confocal and optical microscopy, and tensile testing. Adhesion of micron-sized particles was determined quantitatively using a sonication device. The polydimethylsiloxane moieties lowered the copolymer surface energy due to migration of siloxane moieties to the film’s surface, resulting in a notable reduction in particle adhesion. A further reduction in particle adhesion was achieved by introducing topographical features on a scale of several to tens of microns by a laser ablation technique.
Droplet characterisation of molten caprolactam for additive manufacturing applications
Authors: Fathi Saeed , Dickens Phill
Published: March 2012

Droplet formation characteristics of molten caprolactam, the monomer of nylon 6, are reported in this article as part of research to develop a novel inkjet additive manufacturing process. Initial investigations confirmed the jettability of molten caprolactam at 80 °C with a printhead and recommended a range of parameters for a stable jet array. High-speed imaging was used to study the interactions between the melt and the printhead. Droplets were generated at voltages higher than 12.5 V. Nozzle wetting and crosstalk in adjacent nozzles were observed especially at higher voltages. Jetting frequency did not affect the droplet characteristics. By varying the jetting voltage though significant changes to the droplet shape, evolution and kinetics were observed. Satellite droplets were formed by disintegration of the tail at lengths of about 1 mm when a jetting voltage of 25.0 V was used. An increase of voltage from 15.0 V to 25.0 V increased the droplet velocity from 2 m/s to 8 m/s. Reynolds and Weber numbers predicted there would not be splashing upon droplet impact, which was confirmed by experiments when impinging molten caprolactam droplets on cold and heated substrates. The droplet formation study suggested a set of jetting parameters to be used for the next stage of the research on the inkjet process development.
Image-based approach to optimize the tyre pitch sequence for a reduction in the air-pumping noise based on a genetic algorithm
Authors: Kim Eui-Youl , Hwang Sung-Wook , Lee Sang-Kwon
Published: March 2012

The paper presents a novel approach to solving problems involved in the application of a genetic algorithm to determine the optimal tyre pitch sequence to reduce the tyre air-pumping noise which is generated by the repeated compression and expansion of the air cavity between the tyre pitch and the road surface. The genetic algorithm was used to determine the optimal tyre pitch sequence with a low level of tyre air-pumping noise using the image-based air-pumping model. In the genetic algorithm used in previous studies, there are a number of problems related to the encoding structure and the selection of an objective function. This paper proposes a single encoding element with five integers, a divergent objective function based on an evolutionary process, and the optimal evolutionary rate based on the Shannon entropy in an attempt to solve the problems. The results of the proposed genetic algorithm with an evolutionary process are compared with those of a randomized algorithm. The randomized algorithm is a traditional method used to obtain the tyre pitch sequence. It was confirmed that the genetic algorithm more effectively reduces the peak value of the predicted tyre air-pumping noise. The consistency and cohesion of the obtained simulation results are also improved.
Witnesses in Action
Authors: Hope Lorraine , Lewinski William , Dixon Justin , Blocksidge David , Gabbert Fiona
Published: March 2012

Understanding memory performance under different operational conditions is critical in many occupational settings. To examine the effect of physical exertion on memory for a witnessed event, we placed two groups of law-enforcement officers in a live, occupationally relevant scenario. One group had previously completed a high-intensity physical-assault exercise, and the other had not. Participants who completed the assault exercise showed impaired recall and recognition performance compared with the control group. Specifically, they provided significantly less accurate information concerning critical and incidental target individuals encountered during the scenario, recalled less briefing information, and provided fewer briefing updates than control participants did. Exertion was also associated with reduced accuracy in identifying the critical target from a lineup. These results support arousal-based competition accounts proposing differential allocation of resources under physiological arousal. These novel findings relating to eyewitness memory performance have important implications for victims, ordinary citizens who become witnesses, and witnesses in policing, military, and related operational contexts.
Association between the valine/leucine247 polymorphism of β2-glycoprotein I and susceptibility to anti-phospholipid syndrome: a meta-analysis
Authors: Lee YH , Choi SJ , Ji JD , Song GG
Published: March 2012

Objective: The objective of this paper is to explore whether the valine/leucine247 (Val/Leu247) polymorphism of β2-glycoprotein I (β2GPI) confers susceptibility to anti-phospholipid syndrome (APS) and thrombosis and predicts positivity for anti-β2GPI antibodies. Methods: A meta-analysis was conducted on the associations between the β2GPI Val/Leu247 polymorphism and susceptibility to APS and thrombosis and positivity for anti-β2GPI. Results: A total of 1507 patients with APS and 1450 controls in 12 comparative studies were included in this meta-analysis. Meta-analysis of the β2GPI Val/Leu247 polymorphism showed significant associations between the β2GPI Val allele and APS, thrombosis, and anti-β2GPI positivity (odds ratio (OR) 1.316, 95% confidence interval (CI) 1.068–1.621, p = 0.010; OR 1.908, 95% CI 1.195–3.046, p = 0.007; OR 1.630, 95% CI 1.018–2.609, p = 0.042, respectively). A direct comparison between anti-β2GPI-positive and -negative patients revealed that the frequency of the Val allele was significantly higher in anti-β2GPI-positive patents (OR 1.514, 95% CI 1.017–1.253, p = 0.041). Furthermore, a direct comparison between thrombosis-positive and -negative patients also indicated that the Val/Val + Val/Leu and the Val/Val vs. Leu/Leu genotypes of the β2GPI polymorphism were significantly elevated in patients with thrombosis (OR 2.817, 95% CI 1.200–6.610, p = 0.017; OR 3.312, 95% CI 1.338–8.200, p = 0.010, respectively). Conclusion: This meta-analysis shows that the β2GPI Val/Leu247 polymorphism is associated with susceptibility to APS and thrombosis and with anti-β2GPI positivity.
A3 Process: A Pragmatic Problem-Solving Technique for Process Improvement in Health Care
Authors: Ghosh Manimay
Published: March 2012

Short-term approaches or patch working are the predominant modes of solving process-related problems in organizations. As a result, problems recur at regular intervals and inhibit their smooth functioning. Organizational leaders have adopted various quality initiatives to produce sustainable change, but the existing literature suggests that many of them have met with limited success. The ‘A3 Process’, adapted from Toyota Motor Corporation, has been proposed as a pragmatic problem-solving technique for creating sustainable organizational change. Observing, drawing iconic sketches, discussing with other stakeholders, and experimenting has helped each stakeholder gain a deeper, contextualized understanding of the problem. These activities influenced knowledge validation and/or knowledge creation, both instrumental in transforming the stakeholder’s passive mindset to a collaborative and active mindset. This article presents one of the many applications of the A3 Process that produced enduring change in a health care environment.
Vibration isolation of a beam via negative resistance electromagnetic shunt dampers
Authors: Yan Bo , Zhang Xinong , Niu Hongpan
Published: March 2012

In this study, two novel electromagnetic shunt damping vibration isolators (EMSD-VIs) were developed for the vibration isolation of a beam structure. The proposed isolator utilizes a pair of electromagnetic coils and permanent magnet and a box-shaped spring to generate both variable damping and spring effect. The governing equation of the EMSD-VI-supported beam was established according to Galerkin method. The negative resistance was proposed to improve the performance of the isolator. The stability analysis was investigated to determine the design rules of the shunted negative resistance. The acceleration transmissibility of the beam system was simulated by using passive EMSD-VI control and negative resistance (NR)-EMSD-VI control. The experiment was conducted to verify the theoretical model and the numerical simulation. The experimental results demonstrated that the proposed NR-EMSD-VI is capable of isolating the first-order and the third-order vibrations. Also, a discussion of the resonance frequency shift toward higher value was given.
A morphing trailing edge device for a wind turbine
Authors: Daynes Stephen , Weaver Paul M
Published: March 2012

The loads on wind turbine components are primarily from the blades. It is important to control these loads in order to avoid damaging the wind turbine. Rotor control technology is currently limited to controlling the rotor speed and the blade pitch. As blades increase in length, it becomes less desirable to pitch the entire blade as a single rigid body, but there is a requirement to control loads more precisely along the length of the blade. This can be achieved with aerodynamic control devices such as flaps. Morphing structures are good candidates for wind turbine flaps because they have the potential to create structures that have the conflicting abilities of being load carrying, lightweight and shape adaptive. A morphing flap design with an anisotropic cellular structure is presented, which is able to undergo large deflections and high strains. An aeroelastic analysis couples the work done by aerodynamic loads on the flap, the flap strain energy and the required actuation work to change shape. The morphing flap model is manufactured, and its stiffness is measured.
Vibration suppression of smart nonlinear flexible appendages of a rotating satellite by using hybrid adaptive sliding mode/Lyapunov control
Authors: Azadi E , Eghtesad M , Fazelzadeh SA , Azadi M
Published: March 2012

In this paper, a hybrid adaptive sliding mode/Lyapunov controller is designed for both the rotational maneuver and the vibration control of smart flexible appendages of a satellite moving in a circular orbit. The satellite is considered as a rigid hub and two flexible appendages with attached piezoelectric layers as sensors and actuators. Each appendage is considered as a nonlinear beam undergoing large deflection. These governing equations of motion are obtained using a Lagrange–Rayleigh–Ritz technique and assumed mode method. The dynamic equations of motion are nonlinear and coupled due to the large angle trajectory and appendages large deflection. A through look at the resulting equations shows that the flexible satellite dynamics including the vibrations of the appendages and their rigid maneuver occur in two different time scales. Using the singular perturbation theory, the dynamics of the flexible satellite are divided into two slow and fast subsystems, the former associated with rigid-body maneuver, while the latter is a result of the vibrations of the appendages. Use of this hybrid controller allows us to cope with parameters uncertainty and disturbances of the system. The stability of the hybrid controller is studied by using the Lyapunov approach. Finally, the whole system is modeled and the simulation results show the efficient performance of the proposed hybrid controller.
Recurrent bone marrow aplasia secondary to nilotinib in a patient with chronic myeloid leukemia: A case report
Authors: Prodduturi Prathima , Perry Anamarija M , Aoun Patricia , Weisenburger Dennis D , Akhtari Mojtaba
Published: March 2012

Nilotinib is a potent tyrosine kinase inhibitor of breakpoint cluster region-abelson (BCR-ABL), which has been approved as front-line therapy for newly diagnosed chronic myeloid leukemia in chronic phase and as second-line therapy after imatinib failure in chronic or accelerated phase chronic myeloid leukemia. Tyrosine kinase inhibitors have been associated with myelosuppression and grade 3 or grade 4 cytopenias are not uncommon in chronic myeloid leukemia patients treated with these drugs. There are a few reports of imatinib-associated bone marrow aplasia, but to our knowledge only one reported case of bone marrow aplasia associated with nilotinib. Herein, we report a 49-year-old male patient with chronic phase chronic myeloid leukemia, who developed severe bone marrow aplasia due to nilotinib. Possible mechanisms for this significant adverse drug reaction are discussed along with a review of literature.
Response of antioxidant activity and sensory quality in fresh-cut pear as affected by high O2 active packaging in comparison with low O2 packaging
Authors: Li WL , Li XH , Fan X , Tang Y , Yun J
Published: March 2012

Effects of active modified atmosphere packaging (initial O2/CO2: 5/5; 30/5; and 80/0) and passive packaging [initial O2/CO2: 20.8/0 (air)] on the antioxidant capacity and sensory quality of fresh-cut ‘Yaoshan’ pear stored at 4 °C for 12 days were investigated. Samples stored in high O2 (30% and 80%) packages had higher phenolics and anthocyanin contents compared with those in passive and low O2 packages. After 12 days of storage, phenolics and anthocyanin contents of 80% O2 samples were 2.5 and 12 times, respectively, higher than those in the passive package and 3 and 2 times higher than those in low O2 package. High O2 modified atmosphere packaging was effective in keeping free radical scavenging capacity as measured by the DPPH assay. The sensory evaluation indicated that surface color of cut fruits were stable for at least 12 days in the high O2 modified atmosphere packaging. The results suggested that high O2 modified atmosphere packaging could be used to inhibit browning and prolong the shelf life of fresh-cut ‘Yaoshan’ pears in spite of more than 50% loss in vitamin C content.
Recurrent pulmonary edema secondary to elongated soft palate in a cat
Authors: Corgozinho Katia Barão , Pereira Adriana Neves , Cunha Simone Carvalho dos Santos , Damico Cristiane Brandão , Ferreira Ana Maria Reis , de Souza Heloisa Justen Moreira
Published: March 2012

A 9-month-old intact female Persian cat presented with recurrent pulmonary edema secondary to an elongated soft palate. Endoscopic evaluation of the pharynx and larynx showed that the elongated soft palate was overlying the epiglottis. Partial resection of the soft palate was performed and the cat showed no further respiratory signs. This report is the first description of elongated soft palate causing airway obstruction in a brachycephalic cat.
Toddler autism screening questionnaire: Development and potential clinical validity
Authors: Tsai Wen-Che , Soong Wei-Tsuen , Shyu Yea-Ing Lotus
Published: March 2012

No feasible screening instrument is available for early detection of children with autism in Taiwan. The existing instruments may not be appropriate for use in Taiwan due to different health care systems and child-rearing cultures. The purpose of this study was to develop and test a screening questionnaire for generic autism. The initial 18-item screening questionnaire was developed by a child psychiatrist using face-to-face interviews with 10 families of children with autism and then tested on a sample of families of 18 children with autism and of 59 typically developing children. Of these 18 items, 15 had fair or better item discrimination (kappa >0.20) and were selected for the revised screening questionnaire. In the revised questionnaire, cutoff scores of 5 and 6 offered 100% sensitivity and 96.5% specificity, with the area under the receiver operating characteristic curve of 0.983. The revised screening instrument has high sensitivity and specificity, making it potentially useful for screening Taiwanese children at risk for autism. This instrument should be further tested in a population-based study.
The rubber hand illusion in children with autism spectrum disorders: delayed influence of combined tactile and visual input on proprioception
Authors: Cascio Carissa J. , Foss-Feig Jennifer H. , Burnette Courtney P. , Heacock Jessica L. , Cosby Akua A.
Published: March 2012

In the rubber hand illusion, perceived hand ownership can be transferred to a rubber hand after synchronous visual and tactile stimulation. Perceived body ownership and self–other relation are foundational for development of self-awareness, imitation, and empathy, which are all affected in autism spectrum disorders (ASD). We examined the rubber hand illusion in children with and without ASD. Children with ASD were initially less susceptible to the illusion than the comparison group, yet showed the effects of the illusion after 6 minutes. Delayed susceptibility to the illusion may result from atypical multisensory temporal integration and/or an unusually strong reliance on proprioception. Children with ASD who displayed less empathy were significantly less likely to experience the illusion than those with more intact ability to express empathy. A better understanding of body representation in ASD may elucidate neural underpinnings of social deficits, thus informing future intervention approaches.
Bicycle steering and roll responses
Authors: Prince PJ , Al-Jumaily Ahmed
Published: March 2012

This article investigates the effects of different steering geometries on the steering response, system stability and frequency response of bicycles. A computer model was developed using Simulink™. The model simulates different bicycle designs allowing several different steering geometries to be quantified in terms of performance. It was validated by data available in literature and from an experimental investigation conducted with a bicycle fitted with steering and roll sensors. Three key variables were examined in detail: the head tube angle, front fork rake and bicycle speed. Their actual importance was determined by systematically changing each key variable one at a time while keeping all other terms constant. Large variations in roll and yaw responses show how sensitive bicycles are to small changes in head tube angles and rake dimensions. At higher speeds, the observed steering responses support the common observation that bicycles are more stable and easier to ride at higher speeds. These simulations show the importance of correctly designing a bicycle’s steering geometry in order to optimise steering performance and the sensitivity of bicycles to small changes in geometry.
Spark ignition to homogeneous charge compression ignition mode transition study: a new modelling approach
Authors: Wu Hao , Collings Nick , Etheridge Jonathan , Mosbach Sebastian , Kraft Markus
Published: March 2012

A hybrid spark ignition/homogeneous charge compression ignition engine model for simulating the spark ignition to homogeneous charge compression ignition transition in a four-cylinder gasoline engine is presented. This hybrid spark ignition/homogeneous charge compression ignition model has been developed to provide help in understanding the complicated spark ignition to homogeneous charge compression ignition transition process and in tackling the control problems associated with it. The model was built in Matlab/Simulink, coupled with a tabulated stochastic reactor model and a detailed chemical kinetics mechanism. Typical computational times encountered in the simulation using this model were of the order of seconds for one engine cycle. The model was validated in steady-state spark ignition and homogeneous charge compression ignition operation by experimental data, followed by model-based parametric studies in homogeneous charge compression ignition operation. Then, a spark ignition to homogeneous charge compression ignition mode transition was simulated using the model. The results showed good agreement with experimental data, in terms of cylinder pressure, combustion phasing, air/fuel ratio, residual gas fraction and nitrogen oxides. The high computational efficiency and relatively high accuracy of this model enable its good applicability in experimental design and controller development, and potential use in hardware-in-loop applications.
A fleet-prediction oriented catalyst model for highly transient driving in cold and hot mode conditions
Authors: Weilenmann Martin , Tsinoglou Dimitrios N
Published: March 2012

Various models for simulating catalytic converters are given in the literature. They deal with a wide range of different aspects. In addition to the type of catalytic converter (three-way catalytic converter, diesel oxidation catalytic converter, etc.), the aspect of complexity versus accuracy and speed can be tackled using different approaches. Moreover, the desired use has an influence on the model structure: optimization of catalyst design or prediction of emissions from real-world traffic situations or optimization of air–fuel ratio control?

The model described here has been developed to predict emissions in arbitrary real-world driving patterns, both for hot driving as well as for cold-start situations. As these tests mainly last over 30 minutes (real time), the calculation effort should be small. The model should be easy to parameterize, as it should be applicable to vehicles from traffic.

A model with a reduced set of chemical reactions has been developed with a particular focus on the thermal balance for cold-start cycles. Its outputs are the pollutant emissions at the tailpipe if the emissions, exhaust mass flow and temperature from the engine are given. It is applied to three-way catalytic converters. It models the chemical phenomena almost entirely based on oxygen storage and release reactions, which dominate highly transient situations. The model has been validated against a large database of measured driving cycles, carried out using different types of cars. It presents an acceptable degree of correlation between simulated and experimental results.
An investigation into the hydrodynamic analysis of vessels with a zero or forward speed
Authors: Du Shuang Xing , Hudson Dominic A , Price W Geraint , Temarel Pandeli
Published: March 2012

The occurrence of irregular frequencies is known to affect the prediction of hydrodynamic coefficients, whether a rigid body or hydroelasticity analysis is used. For conventional ship-like structures, these irregular frequencies lie outside the range of practical interest for rigid body motions. On the other hand, for a large ship-like offshore structure, such as a Floating Production, Storage and Offloading unit (FPSO), the irregular frequencies are in the range of practical interest. Furthermore, they can create difficulties for the analysis of vessels treated as flexible bodies and of multi-hulled vessels. In these cases, distinguishing between genuine physical effects (e.g. wave interaction between hulls) and that of irregular frequencies is important.

The aim of this paper is twofold: first, elimination of irregular frequencies for the zero-forward-speed case and, second, improvement in predictions for the forward-speed case through a more accurate evaluation of the waterline integral term. Although the investigations are illustrated for rigid hulls, namely a rectangular box and a Series 60 hull, the methodology and its effects are equally valid for flexible hulls. For the zero-forward-speed case an extended boundary integral method (the lid method) is used, with the imaginary interior free surface placed approximately 0.1% below the mean free surface. It is confirmed that the lid boundary approach is an efficient and robust method for treating irregular frequencies for stationary rigid floating bodies experiencing low-frequency oscillations. For the forward-speed case a treatment of waterline integral terms is introduced, with reference to sources lying on the free surface. The applications highlight the importance of waterline integral terms which are shown to introduce oscillatory behaviour in the predicted hydrodynamic data. It is also shown that, for the forward-speed case, irregular frequencies do not occur; however, as the forward speed tends to smaller values, the hydrodynamic data exhibit oscillations which depend on the treatment of the waterline integral terms and the use of the direct potential or source distribution method. These methods are also suitable for hydroelasticity analysis with a forward speed.
Condom Use by Partner Type Among Military and Police Personnel in Peru
Authors: Villaran Manuel V. , Bayer Angela , Konda Kelika A. , Mendoza Carlos , Quijandria Hilda , Ampuero Julia S. , Apolaya Moises , Palacios Oswaldo , Lescano Andres G. , Vega Antonio M. , Blazes David L. , Kochel Tadeusz , Montano Silvia M.
Published: March 2012

The aim of this study was to analyze the rates of condom use among military and police populations in Peru, focusing on differences in use by type of partner. A Knowledge Attitudes and Practices survey was conducted among 6,808 military and police personnel in 18 Peruvian cities between August–September 2006 and September–October 2007. A total of 90.2% of the survey respondents were male; mean age was 37.8 years and 77.9% were married/cohabiting. In all, 99.5% reported having had sex; 89% of the participants had their last sexual contact with their stable partner, 9.7% with a nonstable partner, and 0.8% with a sex worker. Overall, 20.4% used a condom during their most recent sexual contact. Reasons for nonuse of condoms included the following: perception that a condom was not necessary (31.3%) and using another birth control method (26.7%). Prevention efforts against sexually transmitted diseases should focus on strengthening condom use, especially among individuals with nonstable partners.
Psychological Distress Among Employed Fathers
Authors: Janzen Bonnie L. , Kelly Ivan W.
Published: March 2012

The aim of this study was to compare levels of psychological distress in employed single fathers relative to partnered fathers and to explore the role of psychosocial job quality, work–family conflict, and work–family facilitation as explanations for differences in distress. The data were collected from a cross-sectional telephone survey conducted in a Canadian city. Participants were 486 employed fathers with children living in the household. In addition to experiencing higher levels of psychological distress than partnered fathers ( p = .057), single fathers reported greater work–family conflict, poorer work quality, and lower family-to-work facilitation. Adjusting for the strain-based work–family conflict variables in the regression analysis resulted in the largest reduction to the association between partner status and psychological distress. Future research employing a longitudinal design and subject to lower selection biases is required to tease out the interrelationship between these exposures and to point to the most appropriate policies to support employed single fathers.
Clinical trial designs for testing biomarker-based personalized therapies
Authors: Lai Tze Leung , Lavori Philip W , Shih Mei-Chiung I , Sikic Branimir I
Published: March 2012

Background Advances in molecular therapeutics in the past decade have opened up new possibilities for treating cancer patients with personalized therapies, using biomarkers to determine which treatments are most likely to benefit them, but there are difficulties and unresolved issues in the development and validation of biomarker-based personalized therapies. We develop a new clinical trial design to address some of these issues. The goal is to capture the strengths of the frequentist and Bayesian approaches to address this problem in the recent literature and to circumvent their limitations.

Methods We use generalized likelihood ratio tests of the intersection null and enriched strategy null hypotheses to derive a novel clinical trial design for the problem of advancing promising biomarker-guided strategies toward eventual validation. We also investigate the usefulness of adaptive randomization (AR) and futility stopping proposed in the recent literature.

Results Simulation studies demonstrate the advantages of testing both the narrowly focused enriched strategy null hypothesis related to validating a proposed strategy and the intersection null hypothesis that can accommodate to a potentially successful strategy. AR and early termination of ineffective treatments offer increased probability of receiving the preferred treatment and better response rates for patients in the trial, at the expense of more complicated inference under small-to-moderate total sample sizes and some reduction in power.

Limitations The binary response used in the development phase may not be a reliable indicator of treatment benefit on long-term clinical outcomes. In the proposed design, the biomarker-guided strategy (BGS) is not compared to ‘standard of care’, such as physician’s choice that may be informed by patient characteristics. Therefore, a positive result does not imply superiority of the BGS to ‘standard of care’. The proposed design and tests are valid asymptotically. Simulations are used to examine small-to-moderate sample properties.

Conclusion Innovative clinical trial designs are needed to address the difficulties and issues in the development and validation of biomarker-based personalized therapies. The article shows the advantages of using likelihood inference and interim analysis to meet the challenges in the sample size needed and in the constantly evolving biomarker landscape and genomic and proteomic technologies.
Illegitimate monarchy and legally-sanctioned king-killing in Milton’s Tenure of Kings and Magistrates and Eikonoklastes
Authors: Oldman Elizabeth
Published: March 2012

In my article, I establish how the poet’s pro-regicidal tracts The Tenure of Kings and Magistrates and Eikonoklastes support an evolutionary notion of kingship, and in doing so seek to shift the balance from a concept of monarchical rule in which the differentiation between adequate versus criminal leadership is largely inconsequential to one in which the quality of sovereign leadership matters. I specifically demonstrate how Milton follows Dutch scholar Hugo Grotius, leading proponent of just/unjust martial theory during the sixteenth and seventeenth centuries, to determine that restricted modes of battle were necessary means to the creation and perpetuation of an orderly and organized society, which more and more responded to misuses of sovereign authority by supporting the individual’s right to resist and expel a bad king.
Microstructure and nanoindentation hardness of TiN/AlN multilayer films prepared by pulsed laser deposition
Authors: Tang P H , Song R G , Chai G Z , Mao J
Published: March 2012

TiN/AlN nanoscale multilayer films were deposited on silicon by pulsed laser depositions, with nominal periods of 10, 20, 40 and 100 nm and total thickness of the TiN/AlN multilayer of ∼500 nm. The microstructure, composition and period of samples were characterised by SEM, nanoindentation and friction tests. The SEM result indicates that the microstructure of the TiN/AlN multilayer film has a good period. The nanoindentation test shows that the hardness of the TiN/AlN multilayer films range from 22 to 30·6 GPa, which is higher than that of a single TiN film (17 GPa). The TiN/AlN multilayer film with a maximum hardness value of 30·6 GPa is associated with more effective combination of solid solution hardening (TiAlN) on the interface. This point is confirmed by X-ray photoelectron spectroscopy. The influences of the period on the microstructure and mechanical properties of films are also investigated. The X-ray diffraction patterns indicate that TiN film exhibits nanocrystalline columns, whereas AlN shows a crystallite structure. The TiN/AlN multilayer film presents typical microstructural features for both materials. In tribological tests, a ball on disc test is used to determine the friction coefficients. The coefficient of steady state friction against a Si3N4 ball varies considerably between films grown by different periods. The lowest friction coefficient of μ = 0·33 is shown at the TiN/AlN multilayer film, whereas the TiN and AlN single layer film ranges from 0·33 to 0·82.
Effect of different solution heattreatments on hot ductility of superalloysPart 2 – Allvac 718Plus
Authors: Andersson J , Sjöberg G P , Viskari L , Chaturvedi M
Published: March 2012

The hot ductility of Allvac 718Plus for different solution heat treatments (954°C–15 h, 954°C–1 h, 982°C–1 h and 1050°C–3 h+954°C–1 h) has been investigated using Gleeble testing. Substantial variations in the microstructure among the heat treatments affected the Gleeble test hot ductility only to a very limited extent. Constitutional liquation of the NbC phase was found to be the main cause for the poor ductility at high testing temperatures in the on-heating cycle as well as at the lower temperatures on-cooling. Grain boundary δ phase was seen to assist the constitutional liquation of the NbC phase. Based on established evaluation criteria for Gleeble ductility testing, a ranked indicator for weldability is suggested.
Microstructural, mechanical and electrochemical characterisation of biomaterial ASTM F745 cast by vacuum
Authors: Gregorutti R W , Grau J E , Elsner C I
Published: March 2012

Countergravity low pressure casting (CLA) was performed to enhance the properties of ASTM F745 stainless steel (SS), which is usually used as biomaterial. The macro- and microstructures were compared with those obtained by the conventional process of investment casting (IC). The SS cast by CLA (SSCLA) exhibited a smaller size of solidification cell and finer dendritic microstructure. The average of its dendritic primary spacing was 110·4 μm, while for the same steel cast by IC (SSIC), it was 186·7 μm. The density of non-metallic inclusions δI in the SSCLA was 717 I mm−2, being the majority of them smaller than 1·5 μm. In the case of SSIC, δI was 852 I mm−2, with a size distribution of up to 8 μm. The SSCLA showed a higher breakdown potential than the SSIC, the values being 0·300 and 0·210 V(saturated calomel electrode) respectively, which means a higher resistance to suffer localised corrosion. Finely, the CLA process also allowed obtaining better mechanical properties.
Hardness of silicon nitride thin films characterised by nanoindentation and nanoscratch deconvolution methods
Authors: Liu S. , Huang H. , Gu Y. T.
Published: March 2012

Plasma enhanced chemical vapour deposition silicon nitride thin films are widely used in microelectromechanical system devices as structural materials because the mechanical properties of those films can be tailored by adjusting deposition conditions. However, accurate measurement of the mechanical properties, such as hardness, of films with thicknesses at nanometric scale is challenging. In the present study, the hardness of the silicon nitride films deposited on silicon substrate under different deposit conditions was characterised using nanoindentation and nanoscratch deconvolution methods. The hardness values obtained from the two methods were compared. The effect of substrate on the measured results was discussed.
Effect of sliding speed on wear behaviour of nitrided martensitic stainless steel under boric acid and MoS2 lubrication
Authors: Vadiraj A , Kamaraj M , Sreenivasan V S
Published: March 2012

Sliding counter bodies frequently undergo boundary lubrication at lubricant starved areas with dominated surface interaction under dry sliding condition. The effect of sliding speed (1·0–2·5 m s−1) on the friction and wear performance of nitrided martensitic stainless steel in the presence of dry lubricants like boric acid and MoS2 has been investigated, and the results are presented in this work. Under dry condition, wear loss increases and friction coefficient decreases with sliding speeds. The lubricant coated samples show minimal wear loss at all sliding speeds (2·5 m s−1). The friction coefficient shows a decreasing trend for the MoS2 coated sample, while the boric acid coated sample shows an increasing trend. This is possibly due to the temperature induced conversion of boric acid to boric oxide. The fine debris mixture formed during sliding may also pin the lamellar shearing of solid lubricants to increase friction.
Influence of mechanical properties of tungsten carbide–cobalt thermal spray coatings on their solid particle erosion behaviour
Authors: Santana Y Y , La Barbera-Sosa J G , Bencomo A , Lesage J , Chicot D , Bemporad E , Puchi-Cabrera E S , Staia M H
Published: March 2012

The present investigation has been carried out in order to study the erosion wear behaviour of WC–Co base thermal spray coatings. WC–12Co and WC–10Co–4Cr coatings were deposited by means of high velocity oxygen fuel (HVOF) thermal spraying. The erosion tests were conducted at impact angles of 30 and 90° using SiC particles of ∼50 μm in diameter as erodent, at a velocity of 83·4 m s−1. It has been found that the erosion rate for both coated systems was higher when the test was carried out at an angle of 90°. The through-thickness residual stresses of the coatings, as well as the microstructural characterisation, allowed an explanation of the results and the erosion mechanisms in each case. It has been found that, under the experimental conditions carried out in the present study, the WC–10Co–4Cr coating exhibited a higher erosive wear resistance as compared to the WC–12Co coating.
Tribological properties of nanostructured TiO2 coatings
Authors: Raut N C , Kumar N , Mathews T , Dash S , Tyagi A K , Raj B
Published: March 2012

Nanostructured anatase TiO2 thin films were deposited at 350, 450 and 550°C on crystalline silicon substrates using ultrasonic spray pyrolysis technique. The thickness of the films decreased with increasing temperature whereas roughness and grain size increased. Adhesive strength of the films was found to decrease with substrate temperature. When steel ball (100 Cr6) was used as the counter body, coefficient of friction (CoF) was found to increase with substrate temperature. In the case of films grown at 350°C, when silicon nitride ball were used as the sliding body, the CoF was found to be high. This anomaly is explained on the basis of three body interaction causing large dissipation of energy.
Electrochemical impedance spectroscopy analysis of cold sprayed and arc sprayed aluminium coatings serviced in marine environment
Authors: Zhu Q J , Wang K , Wang X H , Hou B R
Published: March 2012

High velocity arc spraying and cold gas dynamic spraying were applied to prepare the aluminium coating, and electrochemical impedance spectroscopy measurement in combination with scanning electron microscopy analysis of corrosion surface and X-ray diffraction results of corrosion product were used to compare the corrosion behaviour of these two coatings. It was found that there was sparse and porous corrosion product covering on the surface of the arc sprayed aluminium coating through which the Cl− can penetrate into the inner coating interface. In contrast, the surface of the cold sprayed aluminium coating after immersion was less porous and tended to seal the pores in the coating. This kind of structure can obstruct the penetration of corrosion medium into the inner coating surface and reduce the corrosion rate to a certain extent. In addition, the diffusion impedance O was introduced in the electrochemical impedance spectroscopy modelling for the purpose of getting good fitting results.