bluuebunny/crossref_metadata_2025 huggingface dataset:
Clinical significance of presence and extent of extrapancreatic necrosis in acute pancreatitis
Authors: Rana Surinder S , Sharma Vishal , Sharma Ravi K , Chhabra Puneet , Gupta Rajesh , Bhasin Deepak K
Published: September 2014

Background and Aim

Extrapancreatic necrosis (EPN) alone represents a subgroup of pancreatitis with better outcome than patients with pancreatic parenchymal necrosis (PN). However, data on clinical significance of EPN is limited, and significance of the extent of EPN is not known.

Methods

Two hundred thirteen patients (136 [63.8%] males; mean age: 39.8 ± 13.2 years) with acute pancreatitis were prospectively enrolled and followed up till recovery or death. Contrast‐enhanced computed tomography of each patient was retrospectively evaluated for presence of PN and EPN, pleural effusion and ascites. EPN was termed extensive if it extended to paracolic gutters or pelvis.

Results

Twenty‐one (9.9%) patients had interstitial pancreatitis, seven (3.3%) patients had PN alone, 48 (22.5%) patients had EPN alone, and 137 (64.3%) patients had combined PN and EPN. Patients with EPN alone had significantly higher frequency of organ failure than patients with interstitial pancreatitis. Compared with patients with EPN alone, the patients with combined necrosis had significantly higher frequency of pleural effusion (88.2% vs 75%), ascites (41% vs 20.8%), and need for intervention (32.6% vs 14.6%). Patients with extensive EPN (n = 57) had significantly higher frequency of pleural effusion, ascites, and multi‐organ failure than those with limited EPN.

Conclusion

EPN alone should be considered as a separate category of acute pancreatitis as it has less severe course than PN but has more severe course than interstitial pancreatitis. Patients with extensive EPN in spite of having increased frequency of ascites, pleural effusion, and multi‐organ failure had similar outcome as compared to patients with limited EPN.
A Comparative Study of Transulnar and Transradial Artery Access for Percutaneous Coronary Intervention in Patients with Acute Coronary Syndrome
Authors: LIU JUN , FU XIANG‐HUA , XUE LING , WU WEI‐LI , GU XIN‐SHUN , LI SHI‐QIANG
Published: September 2014

Objectives

Transradial access has become commonly used for elective evaluation of patients with coronary artery disease, but it has some disadvantages and has had limited use in the acute coronary syndrome (ACS). Because the diameter of the ulnar artery is usually larger than that of the radial artery, we hypothesized that the ulnar artery could be used as an access for percutaneous coronary intervention (PCI). The present study compares the feasibility, safety, and outcome of transulnar artery and transradial artery access for PCI in patients with ACS.

Methods

We reviewed 636 patients who had PCI for ACS from May 2006 to May 2009. The patients were randomly assigned to transulnar intervention (TUI; 317) or transradial intervention (TRI; 319).

Results

Several outcomes were similar in the TUI and TRI groups: success rate of first puncture, duration of guiding catheter engagement, puncture‐to‐balloon inflation time, final thrombolysis in myocardial grade 3 flow, complications at the vascular access site, and postprocedure complications. The incidence of severe arterial spasm and forearm hematoma in the TUI groups was significantly less than that in the TRI group. At 1‐year follow‐up, the level of blood oxygen saturation at the middle finger and Doppler ultrasonographic characteristics of the ulnar artery did not significantly change from pre‐PCI values for these criteria in either group.

Conclusion

The TUI approach has results and access complications similar to the TRI approach and is a safe and feasible alternative for ACS patients. (J Interven Cardiol 2014;27:525–530)
Molecular characterization and in vitro antifungal susceptibility of 80 clinical isolates of mucormycetes in Delhi, India
Authors: Chowdhary Anuradha , Kathuria Shallu , Singh Pradeep Kumar , Sharma Brijesh , Dolatabadi Somayeh , Hagen Ferry , Meis Jacques F.
Published: September 2014

Mucormycosis is a highly aggressive disease which is usually fatal in immunocompromised patients. The species of mucormycetes show significant differences in susceptibility to amphotericin B, azoles and terbinafine. The precise species level identification for this fungal group could be achieved by internal transcribed‐spacer (ITS) region sequencing. Herein, we present the largest series of antifungal susceptibility data of molecularly characterised isolates of mucormycetes reported so far from India. Eighty isolates originating from 71 patients comprised 50 (62.5%) from pulmonary cases, 15 (19%) from rhino‐orbital‐cerebral, 13 (16.2%) from cutaneous and 2 (2.5%) from disseminated mucormycosis. ITS and D1/D2 regions sequencing of the isolates identified, Rhizopus arrhizus var. delemar (n = 25), R. arrhizus var. arrhizus (n = 15), R. microsporus (n = 17), R. stolonifer (n = 3), Syncephalastrum racemosum (n = 11), Apophysomyces elegans (n = 2), A. variabilis (n = 2), Lichtheimia ramosa (n = 3) and Mucor circinelloides f. lusitanicus (n = 2). Amplified fragment length polymorphism analysis was done to genotype Rhizopus isolates and revealed 5 clusters of R. arrhizus, which were well separated from R. microsporus. Amphotericin B was the most potent antifungal followed by posaconazole, itraconazole and isavuconazole. Etest and CLSI MICs of amphotericin B showed 87% agreement. Overall, the commonest underlying condition was uncontrolled diabetes mellitus. Records of 54 patients revealed fatalities in 28 cases.
Associations of sugar‐sweetened and artificially sweetened soda with chronic kidney disease: A systematic review and meta‐analysis
Authors: Cheungpasitporn Wisit , Thongprayoon Charat , O'Corragain Oisin A. , Edmonds Peter J. , Kittanamongkolchai Wonngarm , Erickson Stephen B.
Published: September 2014

Background/Objectives

The risk of chronic kidney disease (CKD) in patients who regularly drink soda is controversial. The objective of this meta‐analysis was to evaluate the associations between consumption of sugar‐sweetened and artificially sweetened soda and CKD.

Methods

A literature search was performed using MEDLINE, EMBASE and the Cochrane Database of Systematic Reviews from inception until 30 June 2014. Studies that reported odds ratios or hazard ratios comparing the risk of CKD in patients consuming significant amounts of either sugar‐sweetened or artificially sweetened soda versus those who did not consume soda were included. Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated using a random‐effects, generic inverse variance method.

Results

Five studies were included in our analysis of the association between consumption of sugar‐sweetened soda and CKD. The pooled RR of CKD in patients consuming sugar‐sweetened soda was 1.58 (95% CI 1.00–2.49). Four studies were selected to assess the association between consumption of artificially sweetened soda and CKD. The pooled RR of CKD in patients consuming artificially sweetened soda was 1.33 (95% CI 0.82–2.15).

Conclusions

Our study demonstrates statistically significant increased risks of CKD in patients consuming sugar‐sweetened soda, but not in patients consuming artificially sweetened soda. This finding suggests that sugar‐sweetened soda consumption is associated with CKD and may impact clinical management and primary prevention of CKD in high‐risk patients.
What Will the Boss Think? The Impression Management Implications of Supportive Relationships With Star and Project Peers
Authors: Long David M. , Baer Michael D. , Colquitt Jason A. , Outlaw Ryan , Dhensa‐Kahlon Rashpal K.
Published: September 2014

Although impression management scholars have identified a number of tactics for influencing supervisor evaluations, most of those tactics represent supervisor‐targeted behaviors. This study examines the degree to which employees form supportive relationships with peers for impression management purposes. In so doing, we explore this intriguing question: Will employees gain more from forming supportive relationships with “stars” (i.e., top performers who are “on the fast track” in the organization) or “projects” (i.e., “works in progress” who need help and refinement to perform well)? We examined this question in 2 field studies. Study 1 included 4 sources and 2 time periods; Study 2 included 2 sources and 3 time periods. The results showed that supportive relationships with both stars and projects seemed to represent impression management opportunities, insofar as they predicted supervisor positive affect and perceptions of employee promotability. Impression management motives only predicted supportive relationships with stars, however, not projects. Relationships with projects were driven by prosocial motives not concerns about managing images. We discuss the practical and theoretical implications of our results for the managing of impressions and peer relationships.
A PARTIAL DEFENSE OF EXTENDED KNOWLEDGE
Authors: Brogaard Berit
Published: September 2014

The paper starts out by distinguishing two closely related hypotheses about extended cognition. According to the strong hypothesis, there are no intrinsic representations in the brain. This is a version of the extended‐mind view defended by Andy Clark and Richard Menary. On the weak hypothesis, there are intrinsic representations in the brain but some types of cognition, knowledge or memory are constituted by particular types of external devices or environmental factors that extend beyond the skull and perhaps beyond the skin. This type of view was defended, for example, by Andy Clark and David Chalmers. After drawing this distinction and clarifying the notions of causal influence and constitution, I defend the second weaker hypothesis with respect to procedural knowledge and knowledge of action and show why this sort of view supports what we might call a ‘situationist‐friendly virtue epistemology’.
PRAGMATIC INTERVENTIONS INTO ENACTIVE AND EXTENDED CONCEPTIONS OF COGNITION
Authors: Gallagher Shaun
Published: September 2014

Clear statements of both extended and enactive conceptions of cognition can be found in John Dewey and other pragmatists. In this paper I'll argue that we can find resources in the pragmatists to address two ongoing debates: (1) in contrast to recent disagreements between proponents of extended vs enactive cognition, pragmatism supports a more integrative view—an enactive conception of extended cognition, and (2) pragmatist views suggest ways to answer the main objections raised against extended and enactive conceptions—specifically objections focused on constitution versus causal factors, and the mark of the mental.
CAN GROUPS HAVE CONCEPTS? SEMANTICS FOR COLLECTIVE INTENTIONS
Authors: O'Madagain Cathal
Published: September 2014

A substantial literature supports the attribution of intentional states such as beliefs and desires to groups. But within this literature, there is no substantial account of group concepts. Since on many views, one cannot have an intentional state without having concepts, such a gap undermines the cogency of accounts of group intentionality. In this paper I aim to provide an account of group concepts. First I argue that to fix the semantics of the sentences groups use to make their decisions or express their beliefs, we need to appeal to a conventional semantics like that of Lewis. I then argue that the same reasons we have for taking group intentional states to be irreducible to the intentional states of their members apply also to the terms fixed by a conventional semantics. It follows that the meanings of terms in the sentences expressing a group's intentional states are also fixed by facts about the group, not its members. And recognizing this, I argue, amounts to attributing concepts to groups. Finally, I discuss a real‐life example of a group concept—the meaning of ‘meter’ as fixed by the International Bureau of Weights and Measurements—and I discuss the upshot of these considerations for the question of social externalism about concepts.
EPISTEMIC ACTION, EXTENDED KNOWLEDGE, AND METACOGNITION
Authors: Proust Joëlle
Published: September 2014

How should one attribute epistemic credit to an agent, and hence, knowledge, when cognitive processes include an extensive use of human or mechanical enhancers, informational tools, and devices which allow one to complement or modify one's own cognitive system? The concept of integration of a cognitive system has been used to address this question. For true belief to be creditable to a person's ability, it is claimed, the relevant informational processes must be or become part of the cognitive character of the agent, as a result of a process of enculturation. We argue that this view does not capture the role of sensitivity to epistemic norms in forming true beliefs. An analysis of epistemic actions, basic and extended, is proposed as offering an appropriate framework for crediting an agent with knowledge.
MINDS AND MORALS
Authors: Sawyer Sarah
Published: September 2014

In this paper, I argue that an externalist theory of thought content provides the means to resolve two debates in moral philosophy. The first—that between judgement internalism and judgement externalism—concerns the question of whether there is a conceptual connection between moral judgement and motivation. The second—that between reasons internalism and reasons externalism—concerns the relationship between moral reasons and an agent's subjective motivational set. The resolutions essentially stem from the externalist claim that concepts can be grasped partially, and a new moral theory, which I call ‘moral externalism’, emerges.
DEWEY ON EXTENDED COGNITION AND EPISTEMOLOGY
Authors: Vaesen Krist
Published: September 2014

There is a surge of attempts to draw out the epistemological consequences of views according to which cognition is deeply embedded, embodied and/or extended (e‐cog). The principal machinery used for doing so is that of analytic epistemology. Here I argue that Dewey's pragmatic epistemology may be better fit to the task. I start by pointing out the profound similarities between Dewey's view on cognition and that emerging from literature of more recent date. Crucially, the benefit of looking at Dewey is that Dewey, unlike contemporary writers, also devises a corresponding epistemology. I then identify two senses in which contemporary analytic epistemology conflicts with e‐cog—concluding from that the superiority of the Deweyian framework, at least as it concerns accommodating e‐cog.
Ceratocystis fimbriata‐induced changes in the antioxidative system of mango cultivars
Authors: Bispo W. M. S. , Araújo L. , Bermúdez‐Cardona M. B. , Cacique I. S. , DaMatta F. M. , Rodrigues F. A.
Published: September 2014

Mango wilt is one of the most important diseases affecting mango production, yet the physiological mechanisms underlying host responses to this fungal infection are poorly known. The disease attenuation displayed by some mango cultivars might be related to higher antioxidant capacities in leaves. To test this hypothesis, the activities of a range of enzymes (e.g. superoxide dismutase and catalase) and metabolites (e.g. ascorbate and glutathione) involved in the antioxidant system, as well as some markers for oxidative stress (e.g. hydrogen peroxide and malondialdehyde equivalents), were evaluated for 30 days after the inoculation of mango plants withCeratocystis fimbriata. Tommy Atkins plants displayed higher values for the upward, downward and radial fungal colonization of the stem tissues than Ubá plants. In contrast to the working hypothesis, Tommy Atkins plants exhibited more prominent increases in enzyme activities and metabolite concentrations related to oxidative stress responses. These increases were minimal, if any, in Ubá plants. These results suggest that Tommy Atkins plants are less effective at restraining fungal spread through vascular tissues and thus trigger leaf antioxidant defences to cope with the developing stress.
Hyaluronic Acid as Capacitation Inductor: Metabolic Changes and Membrane‐Associated Adenylate Cyclase Regulation
Authors: Fernández S , Córdoba M
Published: September 2014

Contents

The aim of this research was to study the effect of hyaluronic acid on bovine cryopreserved spermatozoa compared with heparin as regards the variation of capacitation induction, cellular oxidative metabolism and intracellular signal induced by membrane‐associated adenylate cyclase to propose hyaluronic acid as a capacitation inductor. Heparin or hyaluronic acid and lysophosphatidylcholine were used to induce sperm capacitation and acrosome reaction, respectively. 2′,5′‐dideoxyadenosine was used as a membrane‐associated adenylate cyclase inhibitor. The highest percentages of capacitated spermatozoa and live spermatozoa with acrosome integrity were obtained by incubating sperm for 60 min using 1000 μg/ml hyaluronic acid. In these conditions, capacitation induced by hyaluronic acid was lower compared with heparin; nonetheless both glycosaminoglycans promote intracellular changes that allow true acrosome reaction in vitro induced by lysophosphatidylcholine in bovine spermatozoa. Oxygen consumption in heparin‐capacitated spermatozoa was significantly higher than in hyaluronic acid‐treated spermatozoa. With all treatments, mitochondrial coupling was observed when a specific uncoupler of the respiratory chain was added. The inhibition of membrane‐associated adenylate cyclase significantly blocked capacitation induction produced by hyaluronic acid, maintaining a basal sperm oxygen uptake in contrast to heparin effect in which both sperm parameters were inhibited, suggesting that the membrane‐associated adenylate cyclase activation is involved in the intracellular signal mechanisms induced by both capacitation inductors, but only regulates mitochondrial oxidative phosphorylation in heparin‐capacitated spermatozoa.
The core of love when caring for patients suffering from addiction
Authors: Thorkildsen Kari M. , Eriksson Katie , Råholm Maj‐Britt
Published: September 2014

Drug addiction is a serious health problem. The aim of this study was to gain an understanding of the core of love when caring for patients suffering from addiction. The study had a hermeneutical approach. Four nurses working at a detoxification unit were interviewed. Data were interpreted using a hermeneutical text interpretation based on Gadamer's hermeneutics. The results revealed the core of love in four dimensions: love as an inner driving force, searching for the human being behind the addiction, faith in the inner power of human beings and love as a movement of giving and receiving. The hermeneutical interpretation revealed the core of love as sacrifice, showing that sacrifice is an ethical dimension and that sacrifice involves searching for the patient's ontological suffering. Sacrifice is connected to faith, and faith in love is decisive for a life without drugs. Sacrifice involves being mutual gifts to one another, a self‐reinforcing motion of sacrifice that energizes the nurses to go on with their work.
Complexity of nursing care in acute care hospital patients: results of a pilot study with a newly developed questionnaire
Authors: Kleinknecht‐Dolf Michael , Grand Francis , Spichiger Elisabeth , Müller Marianne , Martin Jacqueline S. , Spirig Rebecca
Published: September 2014

Aim

The aim of this pilot study was to develop an instrument for measuring complexity of nursing care in hospitalised acute care patients as well as to examine its comprehensibility, its feasibility, the effort required for data collection, and its inter‐rater reliability as well as its face validity.

Methods

This pilot study was designed as a descriptive, explorative cross‐sectional survey with multiple measurements of the patient‐related complexity of nursing care and a supplemental qualitative questionnaire conducted on six units of a Swiss university hospital. The instrument to assess complexity of nursing care was developed on the framework of Perrow and encompasses on three subscales a total of 15 items with a 5‐point Likert scale.

Ethical considerations

The study was reviewed and approved by the Cantonal Ethics Committee.

Results

In total, 866 assessments of complexity of nursing care were carried out on 234 patients. The variability of the results of the six units, from three different specialties, suggests that the sampling was suitable for capturing a wide spectrum of complexity. The results of the three subscales are consistent and the discussion of them with the participating units shows that they are also plausible. The verification of the inter‐rater reliability has satisfactory to high intersubjective correlation of the values. There were also a few suggestions for improving comprehensibility as well as on how to support user application. The time expenditure for the assessment between 2 to 5 minutes per patient was accurately.

Conclusion

With the newly developed questionnaire to measure the complexity of nursing care in acute care hospitals it seems to be possible to assess and to quantify the complexity of nursing care in various acute care hospital settings. Based on the findings and the feedback of the participating users, the questionnaire needs to be improved for large‐scale application.
Depression embodied: an ambiguous striving against fading
Authors: Danielsson Louise , Rosberg Susanne
Published: September 2014

Although depression is associated to physical discomfort, meanings of the body in depression are rarely addressed in clinical research. Drawing on the concept of the lived body, this study explores depression as an embodied phenomenon. Using a hermeneutic phenomenological approach, the analysis of narrative‐based interviews with 11 depressed adults discloses a thematic structure of an embodied process of an ambiguous striving against fading. Five subthemes elicit different dimensions of this process, interpreted as disabling or enabling: feeling estranged, feeling confined, feeling burdensome, sensing life and seeking belongingness. In relation to clinical practice, we suggest that the interdisciplinary team can focus on enhancing the enabling dimensions, for example through guided physical activities to support the patient to feel more alive, capable and connected. Moreover, we suggest that the treatment process benefits from an increased awareness of the ambiguity in the patient's struggle, acknowledging both destructive and recharging elements of the withdrawing, and the perceived conflict in‐between.
A Method of Positional Quality Control Testing for 2D and 3D Line Strings
Authors: Ariza‐López Francisco Javier , Rodríguez‐Avi José
Published: September 2014

This article presents a positional quality acceptance control method for 2D and 3D line strings based on a statistical hypothesis test. Two statistical models are applied together: a Binomial Model is applied over a Base Model. By means of the Base Model the method can be applied to any parametric or non‐parametric error model. The Base Model represents the hypothesis about the error behavior. The Binomial Model is fixed and consists of counting the number F of fail events in a sample of a determined size. The π parameter of the Binomial Model is derived from the Base Model by means of a desired tolerance. By comparing the probabilities associated to F and π a statistical acceptance/rejection decision is achieved. This method allows us to know and control the user's and producer's risk of acceptance/rejection. An example using a 2D line string data set from a commercial product is presented. The extension of the method to the 3D line string case is also presented. In order to facilitate the application of the method, some tables linking π with F and the control sample sizes are presented.
Measuring the Effectiveness of Mentoring as a Knowledge Translation Intervention for Implementing Empirical Evidence: A Systematic Review
Authors: Abdullah Ghadah , Rossy Dianne , Ploeg Jenny , Davies Barbara , Higuchi Kathryn , Sikora Lindsey , Stacey Dawn
Published: September 2014

Background

Mentoring as a knowledge translation (KT) intervention uses social influence among healthcare professionals to increase use of evidence in clinical practice.

Aim

To determine the effectiveness of mentoring as a KT intervention designed to increase healthcare professionals’ use of evidence in clinical practice.

Methods

A systematic review was conducted using electronic databases (i.e., MEDLINE, CINAHL), grey literature, and hand searching. Eligible studies evaluated mentoring of healthcare professionals responsible for patient care to enhance the uptake of evidence into practice. Mentoring is defined as (a) a mentor more experienced than mentee; (b) individualized support based on mentee's needs; and (c) involved in an interpersonal relationship as indicated by mutual benefit, engagement, and commitment. Two reviewers independently screened citations for eligibility, extracted data, and appraised quality of studies. Data were analyzed descriptively.

Results

Of 10,669 citations from 1988 to 2012, 10 studies were eligible. Mentoring as a KT intervention was evaluated in Canada, USA, and Australia. Exposure to mentoring compared to no mentoring improved some behavioral outcomes (one study). Compared to controls or other multifaceted interventions, multifaceted interventions with mentoring improved practitioners’ knowledge (four of five studies), beliefs (four of six studies), and impact on organizational outcomes (three of four studies). There were mixed findings for changes in professionals’ behaviors and impact on practitioners’ and patients’ outcomes: some outcomes improved, while others showed no difference.

Linking Evidence to Action

Only one study evaluated the effectiveness of mentoring alone as a KT intervention and showed improvement in some behavioral outcomes. The other nine studies that evaluated the effectiveness of mentoring as part of a multifaceted intervention showed mixed findings, making it difficult to determine the added effect of mentoring. Further research is needed to identify effective mentoring as a KT intervention.
Filling N-Sided Holes With Trimmed B-Spline Surfaces Based on Energy-Minimization Method
Authors: Liu Xiaodong
Published: September 2014

Using a trimmed rectangular B-Spline surface to fill an n-sided hole is a much desired operation in computer aided design (CAD), but few papers have addressed this issue. Based on an energy-minimization or variational B-Spline technique, the paper presents the technique of using one single trimmed rectangular B-Spline surface to fill an n-sided hole. The method is efficient and robust, and takes a fraction of a second to fill n-sided holes with high-quality waterproof B-Spline surfaces under complex constraints. As the foundation of filling n-sided holes, the paper also presents the framework and addresses the key issues on variational B-Spline technique. Without any precalculation, the variational B-Spline technique discussed in this paper can solve virtually any B-Spline surface with up to 20,000 control points in real time, which is much more efficient and powerful than previous work in the variational B-Spline field. Moreover, the result is accurate and satisfies CAD systems' high-precision requirements.
Analytical Modeling of Chip Geometry in High-Speed Ball-End Milling on Inclined Inconel-718 Workpieces
Authors: Sonawane Harshad A. , Joshi Suhas S.
Published: September 2014

Most often contoured surfaces inclined at several inclinations are generated using ball-end milling of aerospace and automobile components. It is understood that the chip morphology and the corresponding cutting mechanisms change with a change in the tool-workpiece interactions on inclined surfaces. Analytical predictive models to accurately evaluate the undeformed and deformed geometries of chip in ball-end milling are not available. Therefore, this work presents development of analytical models to predict the cutting tool-workpiece interaction as the workpiece inclination changes, in terms of undeformed and deformed chip cross sections. The models further evaluate instantaneous shear angle along any cross section of the tool-work interaction on a ball-end cutter in a milling operation. The models illustrate evaluation of a chip segment and mechanism of its formation in ball-end milling on an inclined work surface. It is observed that the chip dimensions, except deformed chip thickness, increase with an increase in the workpiece inclination angle. Also, a higher workpiece inclination results into an easy flow of the deformed chip over the cutting tool flank, which leads to a higher shear angle during the cut. The predictive chip geometry models corroborate 90% to the experimental results obtained at various workpiece inclinations.
Analysis and Improvement of Metal Transfer Behaviors in Consumable Double-Electrode GMAW Process
Authors: Zhu Ming , Shi Yu , Fan Ding
Published: September 2014

Consumable double-electrode gas metal arc welding (consumable DE-GMAW) is the efficient improvement of DE-GMAW. Due to the variety of coupled arc and metal transfer behaviors, this paper applies static force balance theory to analyze the changes in the forces acting on the main and bypass droplets separately. For main torch, the bypass arc changes the forces affecting on the main droplet, and the main metal transfer becomes more desirable. For bypass torch, with direct current electrode negative (DCEN) polarity, the volume of droplet is big and not easily transfers to the weld pool. In order to improve the bypass metal transfer, a method has been proposed which adds CO2 to pure argon shielding gas to change the forces affecting on the bypass droplet. Then, the welding experiment is carried out to test the effectiveness of this method. It is found that bypass droplet transfers easily and the diameter of bypass droplet is decreased significantly. Also a good weld appearance is acquired.
Design and Performance of a Motor-Driven Mechanism to Conduct Experiments With the Human Index Finger
Authors: Kuo Pei-Hsin , Hayes Jerod , Deshpande Ashish D.
Published: September 2014

Passive properties of the human hands, defined by the joint stiffness and damping, play an important role in hand biomechanics and neuromuscular control. Introduction of mechanical element that generates humanlike passive properties in a robotic form may lead to improved grasping and manipulation abilities of the next generation of robotic hands. This paper presents a novel mechanism, which is designed to conduct experiments with the human subjects in order to develop mathematical models of the passive properties at the metacarpophalangeal (MCP) joint. We designed a motor-driven system that integrates with a noninvasive and infrared motion capture system, and can control and record the MCP joint angle, angular velocity, and passive forces of the MCP joint in the index finger. A total of 19 subjects participated in the experiments. The modular and adjustable design was suitable for variant sizes of the human hands. Sample results of the viscoelastic moment, hysteresis loop, and complex module are presented in the paper. We also carried out an error analysis and a statistical test to validate the reliability and repeatability of the mechanism. The results show that the mechanism can precisely collect kinematic and kinetic data during static and dynamic tests, thus allowing us to further understand the insights of passive properties of the human hand joints. The viscoelastic behavior of the MCP joint showed a nonlinear dependency on the frequency. It implies that the elastic and viscous component of the hand joint coordinate to adapt to the external loading based on the applied frequency. The findings derived from the experiments with the mechanism can provide important guidelines for design of humanlike compliance of the robotic hands.
Stress–Strain Behavior of SAC305 at High Strain Rates
Authors: Lall Pradeep , Shantaram Sandeep , Suhling Jeff , Locker David
Published: September 2014

Electronic products are subjected to high G-levels during mechanical shock and vibration. Failure-modes include solder-joint failures, pad cratering, chip-cracking, copper trace fracture, and underfill fillet failures. The second-level interconnects may be experience high strain rates and accrue damage during repetitive exposure to mechanical shock. Industry migration to lead-free solders has resulted in proliferation of a wide variety of solder alloy compositions. One of the popular tin-silver-copper alloys is Sn3Ag0.5Cu. The high strain rate properties of lead-free solder alloys are scarce. Typical material tests systems are not well suited for measurement of high strain rates typical of mechanical shock. Previously, high strain rates techniques such as the split Hopkinson pressure bar (SHPB) can be used for strain rates of 1000 s−1. However, measurement of materials at strain rates of 1–100 s−1 which are typical of mechanical shock is difficult to address. In this paper, a new test-technique developed by the authors has been presented for measurement of material constitutive behavior. The instrument enables attaining strain rates in the neighborhood of 1–100 s−1. High-speed cameras operating at 300,000 fps have been used in conjunction with digital image correlation (DIC) for the measurement of full-field strain during the test. Constancy of crosshead velocity has been demonstrated during the test from the unloaded state to the specimen failure. Solder alloy constitutive behavior has been measured for SAC305 solder. Constitutive model has been fit to the material data. Samples have been tested at various time under thermal aging at 25 °C and 125 °C. The constitutive model has been embedded into an explicit finite element framework for the purpose of life-prediction of lead-free interconnects. Test assemblies has been fabricated and tested under Joint Electron Device Engineering Council (JEDEC) JESD22-B111 specified condition for mechanical shock. Model predictions have been correlated with experimental data.
Tips on Stochastic Optimal Feedback Control and Bayesian Spatiotemporal Models: Applications to Robotics
Authors: Choi Jongeun , Milutinović Dejan
Published: September 2014

This tutorial paper presents the expositions of stochastic optimal feedback control theory and Bayesian spatiotemporal models in the context of robotics applications. The presented material is self-contained so that readers can grasp the most important concepts and acquire knowledge needed to jump-start their research. To facilitate this, we provide a series of educational examples from robotics and mobile sensor networks.
Numerical Simulations of the Near-Field Region of Film Cooling Jets Under High Free Stream Turbulence: Application of RANS and Hybrid URANS/Large Eddy Simulation Models
Authors: Foroutan Hosein , Yavuzkurt Savas
Published: September 2014

This paper investigates the flow field and thermal characteristics in the near-field region of film cooling jets through numerical simulations using Reynolds-averaged Navier–Stokes (RANS) and hybrid unsteady RANS (URANS)/large eddy simulation (LES) models. Detailed simulations of flow and thermal fields of a single-row of film cooling cylindrical holes with 30 deg inline injection on a flat plate are obtained for low (M = 0.5) and high (M = 1.5) blowing ratios under high free stream turbulence (FST) (10%). The realizable k‐ε model is used within the RANS framework and a realizable k‐ε-based detached eddy simulation (DES) is used as a hybrid URANS/LES model. Both models are used together with the two-layer zonal model for near-wall simulations. Steady and time-averaged unsteady film cooling effectiveness obtained using these models are compared with available experimental data. It is shown that hybrid URANS/LES models (DES in the present paper) predict more mixing both in the wall-normal and spanwise directions compared to RANS models, while unsteady asymmetric vortical structures of the flow can also be captured. The turbulent heat flux components predicted by the DES model are higher than those obtained by the RANS simulations, resulting in enhanced turbulent heat transfer between the jet and mainstream, and consequently better predictions of the effectiveness. Nevertheless, there still exist some discrepancies between numerical results and experimental data. Furthermore, the unsteady physics of jet and crossflow interactions and the jet lift-off under high FST is studied using the present DES results.
Proposal and Experimental Verification of Design Guidelines for Centrifugal Compressor Impellers With Curvilinear Element Blades to Improve Compressor Performance
Authors: Hiradate Kiyotaka , Kobayashi Hiromi , Sugimura Kazuyuki , Ito Toshio , Nishida Hideo
Published: September 2014

This study numerically and experimentally examines the effects of applying curvilinear element blades to fully shrouded centrifugal impellers on the performance of the centrifugal compressor stages. The curvilinear element blades we developed for centrifugal turbomachinery were defined by the coordinate transformations between a revolutionary flow-coordinate system and a cylindrical coordinate system. All the blade sections in the transferred cylindrical coordinate system were moved and stacked spanwise in accordance with the given “lean profile,” which meant the spanwise distribution profile of movement of the blade sections, to form a new leaned blade surface. The effects of the curvilinear element blades on the impeller flowfield were investigated using numerical simulations, and the optimum design guidelines for impellers with curvilinear element blades were considered. Then, a new impeller using these design guidelines was designed and the performance improvement of a new compressor stage was evaluated by numerical simulations. As mentioned in several papers, we numerically confirmed that curvilinear element blades with a negative tangential lean (TGL) profile improved the velocity distribution and stage efficiency because they help to suppress the secondary flows in the impeller. The negative TGL mentioned in this paper represents the lean profile in which the blade hub end leans forward in the direction of the impeller rotation compared to the blade shroud end. At the same time, we also found that the stall margin of these impellers deteriorated due to the increase in relative velocity deceleration near the suction surface of the shroud in the forward part of the impeller. Therefore, we propose new design guidelines for impellers with the curvilinear element blades by applying a negative TGL to line element blades in which the blade loading of the shroud side in the forward part of the impeller is reduced. We confirmed from the numerical simulation results that the performance of the new compressor stage improved compared to that in the corresponding conventional one. The new design guidelines for the curvilinear element blades were experimentally verified by comparing the performance of the new compressor stage with the corresponding conventional one. The measured efficiency of the new compressor stage was 2.4% higher than that of the conventional stage with the stall margin kept comparable. A comparison of the measured velocity distributions at the impeller exit showed that the velocity distribution of the new impeller was much more uniform than that of the conventional one.
Enhancing the Economic Competitiveness of Concentrating Solar Power Plants Through an Innovative Integrated Solar-Combined Cycle With Thermal Energy Storage
Authors: Guédez Rafael , Spelling James , Laumert Björn
Published: September 2014

The present work deals with the thermo-economic analysis of an innovative combined power cycle consisting of a molten-salt solar tower power plant with storage supported by additional heat provided from the exhaust of a topping gas-turbine unit. A detailed dynamic model has been elaborated using an in house simulation tool that simultaneously encompasses meteorological, demand and price data. A wide range of possible designs are evaluated in order to show the trade-offs between the objectives of achieving sustainable and economically competitive designs. Results show that optimal designs of the novel concept are a promising cost-effective hybrid option that can successfully fulfill both the roles of a gas peaker plant and a baseload solar power plant in a more effective manner. Moreover, designs are also compared against conventional combined cycle gas turbine (CCGT) power plants and it is shown that, under specific peaking operating strategies (P-OSs), the innovative concept cannot only perform better from an environmental standpoint but also economically.
Modeling the Energy-Saving Regimes of Curvilinear Bore-Hole Drivage
Authors: Gulyayev V. I. , Gaidaichuk V. V. , Andrusenko E. N. , Shlyun N. V.
Published: September 2014

This paper deals with simulating the energy-saving regimes of drilling deep curvilinear bore-holes with prescribed geometrical imperfections of their axial lines. On the basis of the theory of curvilinear flexible elastic rods, the 3D “stiff-string” drag and torque model of the drill string (DS) bending is elaborated. With its use, it is shown that the contact and friction forces generated by interaction of the DS with the bore-hole surface can be regulated through the combination of its axial and rotary movements. The advanced is applicable for monitoring the ascending–descending operations, drilling, and well completion.
Characterization of Ni thin films following thermal oxidation in air
Authors: De Los Santos Valladares Luis , Ionescu Adrian , Holmes Stuart , Barnes Crispin H. W. , Bustamante Domínguez Angel , Avalos Quispe Oswaldo , González Juan C. , Milana Silvia , Barbone Matteo , Ferrari Andrea C. , Ramos Henry , Majima Yutaka
Published: September 2014

The authors study the thermal oxidation of nickel thin films (50 nm) fabricated by conventional thermal evaporation, resulting from annealing in air at 300, 325, 350, 400, and 700 °C. The characterization is performed by x-ray diffraction, Raman spectroscopy, superconducting quantum interference device magnetometry, and scanning electron microscopy. These techniques show that the oxidation increases with annealing temperature. The formation of granular films of coexisting Ni and NiO is confirmed after annealing at 400 °C. The magnetic measurements indicate coexisting ferromagnetism and antiferromagnetism, corresponding to Ni and NiO contributions. The magnetic hysteresis loops reveal exchange bias in the samples annealed at 235, 350, and 400 °C due to the competition between the exchange interactions at the Ni/NiO interfaces.
Block copolymer self assembly for design and vapor-phase synthesis of nanostructured antireflective surfaces
Authors: Rahman Atikur , Liu Mingzhao , Black Charles T.
Published: September 2014

The authors combine block copolymer self assembly with vapor-phase synthesis for design of antireflective thin film coatings. The nanometer-scale features in patterns formed by cylindrical phase block copolymers provide surface topography for vapor-phase growth of semiconductors and metals by oblique angle physical vapor deposition. The authors control the dimensions and density of the synthesized nanotextures through selection of copolymer molecular weight. A layer of aligned, densely packed germanium wire arrays with diameters much smaller than optical wavelengths acts as an effective optical medium, significantly reducing reflections and improving light coupling into a silicon substrate. A synthesized layer of uniformly sized silver nanoparticles provides antireflection instead through optical excitation of localized surface plasmons. The block copolymer-based synthesis approach allows control of particle shape anisotropy, tuning the frequency of plasmon resonances and expanding the spectral range of antireflection.
Martin Gardner: 100 Years of the Magic of Physics
Authors: Gillaspy John D.
Published: September 2014

2014 marks the 100th anniversary of the birth of Martin Gardner, a man whose writings helped inspire generations of young students to pursue a career in physics and mathematics. From his first to his last, and many in between, Gardner's publications often combined magic and science. A recurring theme was the clever use of physical principles to produce an apparently miraculous effect that stimulated the mind to wonder “how is that possible?” In contrast to the disconnect between science and mystery that one often encounters in teaching today, Gardner embraced these two disparate elements, and fused them into a whole that made learning a joy.
Magnetic Field Due to a Finite Length Current-Carrying Wire Using the Concept of Displacement Current
Authors: Buschauer Robert
Published: September 2014

In undergraduate E&M courses the magnetic field due to a finite length, current-carrying wire can be calculated using the Biot-Savart law.1 However, to the author's knowledge, no textbook presents the calculation of this field using the Ampere-Maxwell law: ∮B·dl=μ0I+ε0dΦdt.1
Drop Tower Physics
Authors: Dittrich William A. (Toby)
Published: September 2014

The drop towers of yesteryear were used to make lead shot for muskets, as described in The Physics Teacher1 in April 2012. However, modern drop towers are essentially elevators designed so that the cable can “break” on demand, creating an environment with microgravity for a short period of time, currently up to nine seconds at the drop tower in Bremen, Germany. Using these drop towers, one can briefly investigate various physical systems operating in this near zero-g environment. The resulting “Drop Tower Physics” is a new and exciting way to challenge students with a physical example that requires solid knowledge of many basic physics principles, and it forces them to practice the scientific method. The question is, “How would a simple toy, like a pendulum, behave when it is suddenly exposed to a zero-g environment?” The student must then postulate a particular behavior, test the hypothesis against physical principles, and if the hypothesis conforms to these chosen physical laws, the student can formulate a final conclusion. At that point having access to a drop tower is very convenient, in that the student can then experimentally test his or her conclusion. The purpose of this discussion is to explain the response of these physical systems (“toys”) when the transition is made to a zero-g environment and to provide video demonstrations of this behavior to support in-class discussions of Drop Tower Physics.
Transformer Impedance Reflection Demonstration
Authors: Layton William
Published: September 2014

Questions often arise as to how a device attached to a transformer can draw power from the electrical power grid since it seems that the primary and secondary are not connected to one another. However, a closer look at how the primary and secondary are linked together magnetically and a consideration of the role of Lenz's law in this linkage may help to clear up this confusion.
Kinetics of the Shanghai Maglev: Kinematical Analysis of a Real “Textbook” Case of Linear Motion
Authors: Hsu Tung
Published: September 2014

A vehicle starts from rest at constant acceleration, then cruises at constant speed for a time. Next, it decelerates at a constant rate.… This and similar statements are common in elementary physics courses. Students are asked to graph the motion of the vehicle or find the velocity, acceleration, and distance traveled by the vehicle from a given graph.1 However, a “constant acceleration-constant velocity-constant deceleration” motion, which gives us an ideal trapezoidal shape in the velocity-time graph, is not common in everyday life. Driving a car or riding a bicycle for a short distance can be much more complicated. Therefore, it is interesting to take a look at a real case of “constant acceleration-constant velocity-constant deceleration” motion.