bluuebunny/crossref_metadata_2025 huggingface dataset:
The Unreasonable Effectiveness of Statistics in Genome Science
Authors: Speed Terry
Published: July 2010

No statistically-random process could ever simulate the structure of human genomes. So why does statistics work so well at analysing them? Terry Speed ponders, and marvels.
Randomisation: What, Why and How?
Authors: Hoare Zoë
Published: July 2010

Randomisation is a fundamental aspect of randomised controlled trials, but how many researchers fully understand what randomisation entails or what needs to be taken into consideration to implement it effectively and correctly? Here, for students or for those about to embark on setting up a trial, Zoë Hoare gives a basic introduction to help approach randomisation from a more informed direction.
Putting Men on A Pedestal: Nobel Prizes as Superhuman Myths?
Authors: Dorling Danny
Published: July 2010

The Nobel prizes for 2010 are to be announced in October. They recognise the best thinkers, the most beautiful minds in their fields; but does the distribution of Nobels accurately reflect the distribution of elite minds? Danny Dorling looks at laureate statistics and finds arbitrariness lurks.
A Meta‐analytic Study of Couple Interventions During the Transition to Parenthood
Authors: Pinquart Martin , Teubert Daniela
Published: July 2010

The present meta‐analysis integrates results of 21 controlled couple‐focused interventions with expectant and new parents. The interventions had, on average, small effects on couple communication (d = .28 standard deviation units) and psychological well‐being (d = .21), as well as very small effects on couple adjustment (d = .09). Stronger effects emerged if the intervention included more than five sessions, included an antenatal and postnatal component, and was led by professionals rather than semiprofessionals.
From Early Childhood to Adolescence: Linking Family Functioning and School Behavior
Authors: Johnson Vanessa K.
Published: July 2010

The present study uses observational assessment of 66 two‐parent families working and playing together when their eldest child is in kindergarten and again in ninth grade to identify distinct patterns of family functioning derived from structural family systems theory. Whereas concurrent assessment of the relationship between family type and adolescents' school behavior was not significant, significant prospective longitudinal relationships between family type assessed in early childhood and ninth‐grade school behavior was indicated. Kindergarteners whose families were primarily characterized by a strong mother‐child alliance were less academically competent, more aggressive/inattentive, and more anxious/depressed/withdrawn at school 9 years later when they were in ninth grade than their peers in more cohesive or father‐child allied families.
Evaluating antimicrobial efficacy of new commercially available silver dressings
Authors: Cavanagh Marion H , Burrell Robert E , Nadworny Patricia L
Published: July 2010

Prevention and treatment of bacterial colonised/infected wounds are critical. Many commercially available silver dressings claim broad‐spectrum bactericidal activity over days and are indicated for serious conditions including burns and ulcers. However, there is no peer‐reviewed literature available for many newer dressings. This study compared the activity of some of these dressings. Six silver‐containing dressings were compared using log reduction, silver release and corrected zone of inhibition assays. Only the nanocrystalline silver dressing was bactericidal against Staphylococcus aureus, and the only other dressing that produced any log reduction was a silver collagen matrix dressing. These two dressings and a silver alginate dressing produced zones of inhibition, although the collagen matrix and alginate dressings had decreasing zone sizes over time, and the latter liquefied after five transfers. The remaining dressings (two ionic silver foam dressings and a silver sulphate dressing) did not produce zones of inhibition. For the foam, alginate and collagen matrix dressings, antimicrobial activity was related to silver release. The silver sulphate dressing released large quantities of silver, but only through the dressing edges, as the wound‐contacting surface appeared to be hydrophobic. The results of this study emphasise the importance of confirming product claims regarding silver dressing efficacy.
Pandemic influenza A (H1N1) during winter influenza season in the southern hemisphere
Authors: Hsieh Ying‐Hen
Published: July 2010

Please cite this paper as: Hsieh Ying‐Hen. (2010) Pandemic influenza A (H1N1) during winter influenza season in the southern hemisphere. Influenza and Other Respiratory Viruses 4(4), 187–197.

Background  Countries in the southern hemisphere experienced sizable epidemics of pandemic influenza H1N1 in their winter season during May–August, 2009.

Methods  We make use of the Richards model to fit the publicly available epidemic data (confirmed cases, hospitalizations, and deaths) of six southern hemisphere countries (Argentina, Brazil, Chile, Australia, New Zealand, and South Africa) to draw useful conclusions, in terms of its reproduction numbers and outbreak turning points, regarding the new pH1N1 virus in a typical winter influenza season.

Results  The estimates for the reproduction numbers of these six countries range from a high of 1·53 (95% CI: 1·22, 1·84) for confirmed case data of Brazil to a low of 1·16 (1·09, 1·22) for pH1N1 hospitalizations in Australia. For each country, model fits using confirmed cases, hospitalizations, or deaths data always yield similar estimates for the reproduction number. Moreover, the turning points for these closely related outbreak indicators always follow the correct chronological order, i.e., case–hospitalization–death, whenever two or more of these three indicators are available.

Conclusions  The results suggest that the winter pH1N1 outbreaks in the southern hemisphere were similar to the earlier spring and later winter outbreaks in North America in its severity and transmissibility, as indicated by the reproduction numbers. Therefore, the current strain has not become more severe or transmissible while circulating around the globe in 2009 as some experts had cautioned. The results will be useful for global preparedness planning of possible tertiary waves of pH1N1 infections in the fall/winter of 2010.
A Hypertension Risk Score for Middle‐Aged and Older Adults
Authors: Kshirsagar Abhijit V. , Chiu Ya‐lin , Bomback Andrew S. , August Phyllis A. , Viera Anthony J. , Colindres Romulo E. , Bang Heejung
Published: July 2010

J Clin Hypertens (Greenwich).

Determining which demographic and medical variables predict the development of hypertension could help clinicians stratify risk in both prehypertensive and nonhypertensive persons. Subject‐level data from 2 community‐based biracial cohorts were combined to ascertain the relationship between baseline characteristics and incident hypertension. Hypertension, defined as diastolic blood pressure ≥90 mm Hg, systolic blood pressure ≥140 mm Hg, or reported use of medication known to treat hypertension, was assessed prospectively at 3, 6, and 9 years. Internal validation was performed by the split‐sample method with a 2:1 ratio for training and testing samples, respectively. A scoring algorithm was developed by converting the multivariable regression coefficients to integer values. Age, level of systolic or diastolic blood pressure, smoking, family history of hypertension, diabetes mellitus, high body mass index, female sex, and lack of exercise were associated with the development of hypertension in the training sample. Regression models showed moderate to high capabilities of discrimination between hypertension vs nonhypertension (area under the receiver operating characteristic curve 0.75–0.78) in the testing sample at 3, 6, and 9 years of follow‐up. This risk calculator may aide health care providers in guiding discussions with patients about the risk for progression to hypertension. J Clin Hypertens (Greenwich). 2010;12:800‐808. © 2010 WileyPeriodicals, Inc.
Isradipine for Treatment of Acute Hypertension in Hospitalized Children and Adolescents
Authors: Miyashita Yosuke , Peterson Do , Rees Jane M. , Flynn Joseph T.
Published: July 2010

J Clin Hypertens (Greenwich).

Severe acute hypertension in pediatric patients requires prompt and controlled blood pressure (BP) reduction to prevent end‐organ damage. The authors aimed to examine the efficacy and safety of isradipine, an orally administered second‐generation dihydropyridine calcium channel blocker, for treatment of acute hypertension in hospitalized pediatric patients. A retrospective analysis of 391 doses of isradipine administered to 282 patients (58% boys) with acute hypertension and median age of 12.8 years (range, 0.1–21.9) was performed. Primary diagnoses included renal disease (n=154), malignancy (45), nonrenal transplant (37), neurologic disease (21), and other (25). The decrease in systolic BP was 16.3%±11.6% (mean ± SD) and diastolic BP was 24.2%±17.2%. BPs were significantly lower in all age groups and in all diagnosis categories following isradipine administration. The decrease in BP was the highest in children younger than 2 years. The mean increase in pulse after a dose was 7±17 beats per minute. Forty adverse events were reported in 33 patients, with emesis and nausea being the most common; 5 of these events were hypotension. The authors conclude that isradipine effectively reduces BP in a wide variety of hospitalized children and adolescents with acute hypertension. A lower initial dose of 0.05 mg/kg may be appropriate in children younger than 2 years. J Clin Hypertens (Greenwich). 2010;12:850–855.
Brain Stimulation: New Vistas for the Exploration and Treatment of Tinnitus
Authors: Plewnia Christian
Published: July 2010

Aims: Tinnitus, the perception of sounds or noise in the absence of auditory stimuli, is a frequent and often severely disabling symptom of different disorders of the auditory system. Attempts to develop evidence‐based therapies have been thwarted by a poor understanding of the underlying pathophysiology. However, recent work points toward a pivotal role of maladaptive cortical reorganization in the generation and perpetuation of tinnitus. Changes in the representation of sounds, abnormalities of oscillatory activity, and hyperactivity in higher order areas of auditory processing have been linked with the perception of tinnitus. Brain stimulation techniques have entered the field and have opened exciting new perspectives for the modulation of dysfunctional brain activity. In this review, a comprehensive overview on the use of brain‐stimulation techniques in the exploration and experimental treatment of tinnitus is provided. Discussions: Noninvasive and invasive brain stimulation techniques, for example, transcranial magnetic stimulation (TMS), direct current stimulation (tDCS), and direct electrical cortical stimulation gave rise to a new line of investigation in tinnitus research. First, it has been shown that focal interference with presumably pathological cortical function can reduce tinnitus at least transiently. Second, the reduction of tinnitus‐associated enhancement of cortical activity by neuronavigated TMS has been demonstrated to ameliorate tinnitus. Third, preliminary data suggest that repeated application of TMS or continuous cortical stimulation may lead to a longer lasting suppression of tinnitus. Conclusions: These proof of principle studies point toward a new option for the investigation and neurophysiology based treatment of tinnitus. Based on these findings, larger scale randomized clinical trials are needed to explore the efficacy of different brain stimulation techniques and parameters as well as the optimal target sites and treatment schedules. Particularly, a careful evaluation of clinical relevance under consideration of an adequate sham control and attention to possible unwanted side effects of these new interventions are indispensable.
La valeur économique de l’audit et son efficacité dans le fonctionnement de l’école publique
Authors: SAITO YOSHIE , MCINTOSH CHRISTOPHER S.
Published: July 2010

Les auteurs examinent l’incidence de l’audit sur le fonctionnement de l’école publique en poursuivant deux objectifs : déterminer si les audits procurent des avantages économiques aux parties prenantes et définir l’incidence de la complexité des règles à observer sur l’efficacité de l’audit. Utilisant des données relatives au temps consacréà l’audit et profitant de l’occasion unique offerte par la Quality Basic Education Act en Georgie, les auteurs estiment le rendement relatif des activités des arrondissements scolaires au moyen d’une méthode stochastique d’estimation des frontières. Ils constatent que l’audit produit de véritables avantages économiques pour les parties prenantes en atténuant le manque d’efficience de l’utilisation des ressources scolaires. Ils constatent également que la rigueur des règles à observer réduit l’efficacité de l’audit mais que l’expérience des auditeurs peut contribuer à surmonter ce problème. Le fait que les coûts d’audit ne soient pas communiqués entrave la réalisation d’une analyse coûts‐avantages des nouvelles exigences. L’analyse des auteurs vient confirmer la thèse selon laquelle l’audit est indispensable à l’établissement de mécanismes de gouvernance et la communication des coûts d’audit est importante dans l’évaluation adéquate d’une nouvelle politique.

Les données pertinentes peuvent être obtenues auprès des sources publiques indiquées dans le texte.
Serum glycated albumin, but not glycated hemoglobin, is low in relation to glycemia in men with hypertriglyceridemia
Authors: Koga Masafumi , Murai Jun , Saito Hiroshi , Mukai Mikio , Kasayama Soji
Published: July 2010

Aims/Introduction:  Serum glycated albumin (GA) and glycated hemoglobin (HbA1c) are influenced by plasma glucose levels, and are used for monitoring chronic glycemic control in diabetic patients. Both glycated proteins are known to be influenced by various factors other than plasma glucose levels. In the present study, we examined the effects of hypertriglyceridemia on them.

Materials and Methods:  The present study comprised 273 non‐diabetic men. They were grouped into men with normotriglyceridemia (serum triglyceride [TG] <150 mg/dL) and those with hypertriglyceridemia (serum TG ≥150 mg/dL).

Results:  Body mass index (BMI) and high sensitivity C‐reactive protein (hs‐CRP) were significantly higher in the 160 men with hypertriglyceridemia than the 113 men with normotriglyceridemia. In men with hypertriglyceridemia, as compared with those with normotriglyceridemia, fasting plasma glucose, 2‐h plasma glucose after 75 g oral glucose tolerance test, and HbA1c were significantly higher. By contrast, serum GA was significantly lower in men with hypertriglyceridemia. BMI‐adjusted serum GA was also significantly lower in these men. In a multivariate analysis, serum TG was an inverse explanatory variable for serum GA.

Conclusions:  Serum GA is low in relation to plasma glucose levels in men with hypertriglyceridemia. This might be caused by increased albumin metabolism associated with hypertriglyceridemic state. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00049.x, 2010)
Angiofibrolipoma of the oral cavity
Authors: Epivatianos Apostolos , Kolokotronis Alexandros , Matiakis Apostolos , Poulopoulos Athanasios
Published: July 2010

We describe an unusual and rare case of a lipoma variant known as angiofibrolipoma. A literature search revealed only a few cases of angiofibrolipoma which were located in different anatomical sites; no case of angiofibrolipoma in the oral cavity has been previously reported. We present and discuss the histopatholological–immunohistological findings and features. Angiofibrolipoma histologically consists of mature adipocytes, blood vessels, and bundles of collagenous connective tissue with low to moderate cellularity. It is not encapsulated, but is histologically distinct from surrounding tissue. Positive immunohistological staining with CD‐34 presented a large number of blood vessels of different sizes located between collagen fibers and adipocytes. The treatment of choice for a patient with angiofibrolipoma is surgical excision, which is expected to be curative.
Combining stable isotope enrichment, compartmental modelling and ecological network analysis for quantitative measurement of food web dynamics
Authors: Lee Ka‐Man , Lee Shing Yip , Connolly Rod M.
Published: July 2010

1. Quantitative food web analysis is made difficult by the need for simultaneous measurement of multiple carbon (C) flows. C flow rates can potentially be quantified indirectly using conventional methods such as gut contents analysis, but the involvement of many conversion factors and assumptions results in significant errors in the final estimation. Such difficulties have limited quantitative data on food web dynamics, restricting community‐level hypothesis testing.

2. We conducted laboratory microcosm and field experiments, using combined enriched stable isotope (13C), compartmental modelling and ecological network analysis (ENA) as a novel approach to quantifying food web dynamics. Feasibility of this approach was demonstrated via the quantification of C flow, backflow and cycling in a subtropical estuarine sandflat food web comprising three trophic levels: microphytobenthos (MPB), three dominant meiofaunal groups (juvenile polychaetes, harpacticoid copepods and nematodes) and soldier crabs (Mictyris longicarpus).

3. Enriched sodium bicarbonate (NaH13CO3) was used to trace C flow. The compartmental modelling software WinSAAM quantified C flow by comparing the temporal patterns of producer and consumer 13C enrichment. Network analysis software EcoNet was used to assess food web dynamics by providing system indices that quantified the flows and food web interactions.

4. This approach allows concurrent quantitative assessment of food web structure and ecosystem functioning. WinSAAM results showed that C return rate from nematodes to MPB was greater than the other two meiofaunal groups and soldier crabs assimilated more C from nematodes than from the other two meiofaunal groups. System indices from EcoNet suggested that indirect flow contributed more than direct flow in this system. Unique capabilities of this approach in food web studies and assumptions underlying the proposed and conventional food web analytical approaches are discussed.

5. Another significant advance of this approach is that it allows sensitive quantification of trophic linkages in a food web without requiring equilibrium to be achieved, thus enabling instantaneous assessment of the relative importance of various C flow pathways. Specific hypotheses about food web dynamics, such as the impact of eutrophication and urbanization, can then be tested quantitatively through manipulative experiments by comparing indices reflecting system behaviour.
Dental diastemata and periodontal disease secondary to axially rotated maxillary cheek teeth in three horses
Authors: Casey M. B. , Tremaine W. H.
Published: July 2010

Malerupted axially rotated maxillary cheek teeth (CT) were identified as the primary cause of diastemata and severe periodontitis in 3 horses. Diastema widening and periodontal debridement was performed initially in one case but did not resolve clinical signs. Subsequently, all 3 cases underwent extraction of the axially rotated teeth per os without complication. Follow‐up indicated remission of periodontitis and signs of oral pain. In these cases, maxillary CT had erupted in a manner that resulted in axial rotation of CT with undulating buccal and palatal surfaces aligned with the interproximal surfaces of adjacent normally orientated teeth. This resulted in poor interproximal compression and diastemata causing severe periodontitis. Axially rotated maxillary CT and the severe periodontitis that they precipitate, have not been previously described as a discrete dental disease entity.
A Comparative Study of the Performance of a SI Engine Fuelled by Natural Gas as Alternative Fuel by Thermodynamic Simulation
Authors: Dashti Mehrnoosh , Hamidi Ali Asghar , Mozafari Ali Asghar
Published: July 2010

With the declining energy resources and increase of pollutant emissions, a great deal of efforts has been focused on the development of alternatives for fossil fuels. One of the promising alternative fuels to gasoline in the internal combustion engine is natural gas [1–5]. The application of natural gas in current internal combustion engines is realistic due to its many benefits. The higher thermal efficiency due to the higher octane value and lower exhaust emissions including CO2 as a result of the lower carbon to hydrogen ratio of the fuel are the two important feature of using CNG as an alternative fuel. It is well known that computer simulation codes are valuable economically as a cost effective tool for design and analysis of the engine operations. In the present work the use of an exiting spark ignition engine to run on both gasoline and CNG is evaluated by thermodynamic simulation of the engine cycle. The stepwise calculations for pressure and temperature of the cylinder at compression process, ignition delay time, combustion and expansion processes have been considered. The first law of thermodynamics is applied for all steps and Newton-Raphson method is used for the numerical solution. Temperature dependent specific heat capacity and as a result specific enthalpy, entropy, internal energy and specific Gibbs functions are calculated in each step. Two zones model for the combustion process simulation has been used and the mass burning rate is predicted by considering the propagation of the flame front spherically. The performance characteristics including power, IMEP, ISFC, thermal efficiency and emissions concentration of SI engine on both gasoline and CNG fuel are determined by the model. In order to validate the model, the results are compared with the corresponding experimental data. It is found that the simulated results show reasonable agreement with the experimental data.
Generating Mechanism of Oilpan Moan Noises of Diesel Engines
Authors: Kimura Jouji , Takahashi Yusuke
Published: July 2010

The noise of diesel engines operating at low idle is an important noise evaluation criterion in both commercial vehicles and passenger cars. At low idle, a quiet, pleasant noise is required. Therefore, any unusual noises that occur at low idle represent a serious problem, and the noises must be prevented. This paper presents the characteristics of the moan noise, which is an unusual noise that radiates from the oilpan at low idle, and the mechanism by which the moan noises are generated in a diesel engine. In addition, a means of preventing the moan noises is discussed.
Study the Effect of Torsional Vibration on Valvetrain Dynamic in a Heavy Duty Diesel Engine Using Multi-Body Dynamic
Authors: Mehrgou Mehdi
Published: July 2010

Today, due to technical, commercial and environmental requirements, internal combustion engines especially heavy duty diesel engines must operate with high cylinder pressures and the components must be optimized for the best performance. Heavy duty diesel engines usually rotate the driven machinery with a large inertia such as generators, or ship propeller. A crankshaft is subjected to periodic dynamic loads; also other inconsistencies could make misfire in engine and because of the torsional vibration in engine, the crankshaft has fluctuating instantaneous speed. Due to the essence of this type of the engine which has heavy parts, beside the robust design of them, and relatively high torques which need to rotate the camshaft, these engines valvetrain normally drive with gears. In consequence the rotating speed of engine crankshaft completely transfer to the camshaft because of high amount of crank train’s inertia in comparison with the valve train and in some cases using the damper for camshaft is required. Modern calculation methods allow for the precise determination of system dynamic and loads. Thus, it is possible to consider design margins that ensure sufficient reliability to avoid undesired dynamic behavior which could lead to structural failures, besides avoiding the components over sizing. In this paper ADAMS\Engine commercial software has been used for simulating the coupled engine cranktrain and valve train subsystems of an engine under development. The engine complete dynamic simulation with Multi-Body Dynamic tool including backlash in gear train and torsionally flexible camshaft, prepare a good model for study the effect of engine cranktrain dynamics on its valvetrain.
Normalized Knock Indicator for Natural Gas S.I. Engines: Methane Number Requirements Prediction
Authors: Saikaly Khalil , Le Corre Olivier , Rahmouni Camal , Truffet Laurent
Published: July 2010

Design of engines and associated nominal settings are normally computed and optimized so as to provide maximum performance, i.e. compromise between efficiency and emissions. For Combined Heat and Power (CHP) applications fuelled by gas network, this conception is adapted for a large range of gas chemical composition, up to a limit. The indicator used to describe gas quality is the methane number (MN). Hence, engine manufacturers normally supply specific information such as nominal engine settings and its associated limit value for the methane number (MNL). When the engine is operating under its nominal settings, a low grade gas (MN < MNL) can lead to engine knock. Knock is caused by auto-ignition of the end gas ahead of the flame in spark-ignition engine. Heavy knock can severely damage engine piston, constituting a main constraint for optimization of engine operating conditions. For an engine setting ES, (the vector ES includes the spark advance SA, the air fuel ratio AFR and the load), methane number requirement (MNR) is defined such as the minimum value of MN above which no-knock is ensured. The objective of this paper is to predict MNR as a function of engine setting for three engines. Simulation results show that the critical value of the considered knock criterion varies from an engine to another. A new normalized knock indicator based on the energy ratio is proposed to enable this comparison: laminar flame speed is assumed to be more sensible to MN variation than internal fluid dynamics (swirl, tumble, and squish) due to engine design.
The Effects of Intake Plenum Volume on the Performance of a Small Naturally Aspirated Restricted Engine
Authors: Hamilton Leonard J. , Cowart Jim S. , Lee Jasen E. , Amorosso Ryan E.
Published: July 2010

Intake tuning is a widely recognized method for optimizing the performance of a naturally aspirated engine for motorsports applications. Wave resonance and Helmholtz theories are useful for predicting the impact of intake runner length on engine performance. However, there is very little information in the literature regarding the effects of intake plenum volume. The goal of this study was to determine the effects of intake plenum volume on steady state and transient engine performance for a restricted naturally aspirated engine for Formula SAE (FSAE) vehicle use. Testing was conducted on a four cylinder 600 cc motorcycle engine fitted with a 20 mm restrictor in compliance with FSAE competition rules. Plenum sizes were varied from 2 to 10 times engine displacement (1.2 to 6.0 L) and engine speeds were varied from 3,000 to 12,500 RPM. Performance metrics including volumetric efficiency, torque and power were recorded at steady state conditions. Experimental results showed that engine performance increased modestly as plenum volume was increased from 2 to 8 times engine displacement (4.8L). Increasing plenum volume beyond 4.8L resulted in significant improvement in performance parameters. Overall, peak power was shown to increase from 54 kW to 63 kW over the range of plenums tested. Additionally, transient engine performance was evaluated using extremely fast (60 msec) throttle opening times for the full range of plenum sizes tested. In-cylinder pressure was used to calculate cycle-resolved gross indicated mean effective pressure (IMEPg) development during these transients. Interestingly, the cases with the largest plenum sizes only took 1 – 2 extra cycles (30–60 msec) to achieve maximum IMEPg levels when compared to the smaller volumes. In fact the differences were so minor that it would be doubtful that a driver would notice the lag. Additional metrics included time for the plenums to fill and an analysis of manifold absolute pressure (MAP) and peak in-cylinder pressure development during and after the throttle transient. Plenums below 4.8L completely filled even before the transient was completed.
Absolute Metastable Limit of Liquids and Gas-Liquid Solutions
Authors: Kwak Ho-Young , Kim Hyo-Won , Ko Ilgon
Published: July 2010

The absolute metastable limit, a one molecule critical cluster formation in the nucleation theory, was obtained by a thermodynamic stability analysis. The tensile strength values obtained for several organic liquids by centrifugal method turned out to be about 50% of the absolute metastable limit, while the tensile strength of water, measured in microscopic inclusions, is close to the absolute metastable limit. On the other hand, the tensile strength values estimated at the superheat limit was about 17% of the absolute limit and the decompression amount for gas bubble formation is about 12% of the absolute limit.
Calculations of Pressure Drop in a Circular Duct Using the Traditional Method Compared to That Using the Constricted Flow Diameter
Authors: Janna William S.
Published: July 2010

The traditional method of calculating pressure drop in a pipe that conveys a fluid involves use of the Moody Diagram. This diagram is a correlation of data with friction factor plotted as a function of Reynolds number and relative roughness. A new graphical representation of these data has been formulated, and makes use of what is known as the constricted flow diameter. The background for this new correlation is based on using a pipe diameter less twice the average roughness height. A new “modified” Moody Diagram has been produced based on the constricted flow diameter. The presence of roughness features on the inside pipe wall has an effect on the flow along the pipe surface which is not accounted for in the traditional Moody diagram. The new diagram accounts for this effect. To demonstrate the use of the new diagram, several example problems have been formulated and solved using the traditional and the modified diagrams. Calculations indicate that at the smaller pipe sizes, the use of the constricted flow diameter yields significantly different results from those obtained in the traditional way. These results have a major influence on modeling flows in mini- and in micro-channels. Laminar and turbulent flows are both affected.
Modeling Piezoelectric Tube Scanner With Hysteresis and Creep by Finite Element Method
Authors: Chung S. H. , Fung Eric H. K.
Published: July 2010

An accurate finite element (FE) model of piezoelectric tube actuator with nonlinearities is proposed in this paper. Both of the hysteresis and the creep are the first to be implemented together into the model in order that the simulation is more precise to account for the dynamic behavior of the piezoelectric tube actuator in the reality. Prandtl-Ishlinskii (PI) operators and creep operators are adopted to formulate the nonlinear constitutive equations. As a result, nonlinear ordinary differential equations can be derived through the energy approach and Hamilton’s Principle. It is observed that the simulation results exhibit nonlinearly with either step or triangular input. They, moreover, agree quite well with the experimental results. The effect on the output response due to the different dimensions of electrode is also investigated. Finally, a proportional controller is implemented to reveal the controllability of this nonlinear FE model. Simulation results also demonstrate that the nonlinear FE model can be used for controller design.
Core Drilling Versus Chisel Drilling With an Eye on Sustainability
Authors: Hamade R. F. , Jawahir I. S.
Published: July 2010

Drilling constitutes about 40% of all machining operations performed. In this perceptive paper, we take a fresh look at the process of drilling with an eye on sustainability. We first explore the cutting regimes along the classical, chisel-type drill’s cutting tip and look for the pressure coefficient distributions along the length of the lip. We then focus our attention on the outermost regions where mostly 2-D cutting takes place and leading to efficient machining. These regimes are those that core (periphery) drills cut through creating the hole by slicing through the hole perimeter while leaving the hole’s internal regions untouched. Several experiments and calculations were conducted with the results confirming that generated forces are smaller for periphery drilling as compared with chisel-type drilling. With the considerable energy savings either directly through cutting power or indirectly through reuse, it is proposed that traditional drilling are replaced by periphery drilling whenever feasible, e.g., drilling of through holes with relatively large diameters. This can be performed by tools that resemble the ‘core drill’ after being redesigned to address several potential processing drawbacks. Tremendous savings in power can be realized (including corresponding reduction in heat generation and tooling temperature) while yielding longer lasting tools as well as more durable products. Several other potential sustainability-related benefits are also realized.
Study on Model Predictive Control to Minimize Temperature Change of Vertical Plate With Varying Heat Generation
Authors: Hirasawa Shigeki , Ito Shinya , Koike Kazuya
Published: July 2010

Precise process temperature control of 0.001°C under circumstances of noise-temperature change of 0.1°C is required in semiconductor manufacturing process. We studied optimum control method to minimize temperature change at an object position in a 2-dimensional vertical plate with a varying noise-heat-generation and a control-heater. We numerically calculated 2-dimensional unsteady thermal conduction in the plate with feedback control, feed-forward control, and model predictive control of the control-heat-generation. The temperature change at the object position can be decreased 1/80 times smaller than that without control-heat-generation using the feedback control with two monitoring temperatures. The temperature change at the object position can be decreased 1/1000 times (0.002°C) using the model predictive control of 5 s interval with step response pattern as a dynamic predictive model. We found that the accuracy of the dynamic predictive model is very important for precise temperature control. Experiment was performed for the model predictive control with a network model as the dynamic predictive model, and the experimental result agreed with the calculation result.
Heat Transfer Enhancement Due to Flow Pulsation at Various Frequencies
Authors: Hessami Mir-Akbar , Zulkifli Nurin Wahida
Published: July 2010

This paper reports on the results of an experimental investigation of the effects of flow pulsation on heat transfer in a horizontal pipe. For this purpose, solenoid valves and a frequency generator were used to pulse water back and forth through a heated horizontal stainless steel pipe with an internal diameter of 11.6mm. Pulsation frequencies from 0.025 to 1.0Hz for various flow rates in the range 7,000<Re<70,000 were investigated. Pulsation amplitude was regularly adjusted in order to create a “reverse flow” condition. All experiments were carried out for the case of a non-zero net flow through the pipe. For the case of f = 0.25Hz and nearly all flow rates, up to 200% heat transfer enhancement compared to steady flow was obtained. For f <0.05Hz as well as for f >0.7Hz some reduction in heat transfer compared to steady flow was measured. A graph of heat transfer data for all pulsating flows vs Womersley number (Wo) showed that the optimum Wo which produces the highest heat transfer for this study was about 10. Other studies in the published literature also have reported an optimum Wo but its value appear to depend on the fluid properties and the hardware used in various studies.
Hydrothermal Conversion of Cattle Manure to Biooil: Biooil Definitions
Authors: Yin Sudong , Dolan Ryan , Tan Zhongchao
Published: July 2010

A number of researchers have reported that biooil was produced through hydrothermal conversion of different types of biomass. However, it is difficult to evaluate and compare these biooils in terms of yields and chemical properties. They applied different organic solvents to extract biooil from products after hydrothermal conversion of biomass. The purpose of this study is to assess the impact of extraction solvents on the quantity and chemical structure of biooil. Cattle manure was used as one type of biomass feedstock for biooil production. And dichloromethane (CH2Cl2), chloroform (CHCl3) and diethyl ether (C4H10O) were used for biooil extraction. Results showed that extraction solvents influenced biooil yields. The highest biooil yield of 48.78 wt% of volatile content of cattle manure was obtained when using CH2Cl2 solvent. The main components of biooil extracted by CH2Cl2 and CHCl3 were ketones and carboxylic acids, while those extracted by C4H10O were aromatic chemicals. In terms of elemental compositions and high heating values of biooil, no statistically apparent differences were caused by different solvents. The mean elemental compositions (by weight) of biooils were carbon of 73.79%, hydrogen of 8.18%, nitrogen of 4.38% and oxygen of 13.65%. And the mean high heating value of biooil was 36.74 MJ/kg.
Experimental Research on the Comparison of LDA and PIV Measuring Systems for the Determination of the Air Velocity Inside a Square Channel
Authors: Dalkılıc¸ Ahmet Selim , Ku¨rekci Nuri Alpay , Atayılmaz S¸evket O¨zgu¨r
Published: July 2010

In this study, the comparison of the accuracy of the results obtained from different fluid velocity measuring systems such as LDA (Laser Doppler Anemometer) and PIV (Particle Image Velocimetry) devices are presented to determine the air velocity profile inside a square channel. These measuring systems are essential and important for the aerodynamic design of vehicles, trains and planes. The paraffin oil was chosen due to their ability of following the air movement inside the channel. The air temperature was around room temperature and it was flowing by means of a compressor in the horizontal Plexiglas channel having 30 × 30 mm square cross section and a length of 1200 mm. Optical laser device was used to illuminate the flow area in the PIV system, and it also has a significant role on the measuring in the LDA system. The detailed description of design and development of the test apparatus, control devices, instrumentation, and the experimental procedure are reported and the study of experimental setups from the available literature survey with the existing one are compared in this paper. Alteration of air velocity at the cross section of the test tube during stable flow at extremely low velocities such as 0–0.08 m/s was measured by these measuring systems sensitively and compared with each other. Characteristics of velocity profile in the test channel are found to be in good agreement with White’s results.
Submerged Jet Mixing of Non-Newtonian Fluids in a Waste Tank
Authors: Munroe Norman , Philippidis George , Singh Gill Puneet K. , Haider Waseem , Amruthaluri Sushma , Pulletikurthi Chandan , Pandya Smit
Published: July 2010

Unsteady jet mixing of Non-Newtonian fluids was investigated in order to develop a mixing correlation for treatment of stored radioactive waste prior to disposal. The radioactive waste was simulated by using carbopol mixtures, which possess both Newtonian and Non-Newtonian fluid rheological characteristics. A particle image velocimetry (PIV) technique with high spatial and temporal resolution was used to measure jet axial velocity, vector field velocity, and mixing properties of the carbopol mixtures. The relationship between the decaying jet axial velocity, tank geometry, fluid rheology and initial jet velocity were determined. A mathematical correlation was developed to estimate jet velocity in submerged jet-agitated tanks using the Buckingham Pi theorem and Dimensionless Numbers that influence the jet velocity and agitation in the tank.
Five-Bar Cylinder-Crank Two-DOF Parallel Manipulators for Singularity-Free Path Generation
Authors: Zhou Hong , Minupuri Swetha , Indroju Shilpa , Gorti Vasuda
Published: July 2010

Parallel manipulators have the merits of high stiffness, load-bearing, operation speed and precision positioning capabilities that are required in many industrial applications. The main challenges for parallel manipulators are their limited workspace and singularity-free path generation capability. This paper is focused on the singularity-free path generation of five-bar cylinder-crank two-DOF parallel manipulators. The linkage feasibility conditions are derived based on the elimination of dead point position within the workspace. The workspace is generated using the curve-enveloping theory. The singularity characteristics and linkage configurations are presented. The singularity-free path generation capability is analyzed. The performance index contours within the workspace are produced using the condition number of the manipulator Jacobian matrix. This paper shows that five-bar cylinder-crank two-DOF parallel manipulators can be used as effective singularity-free path generators if properly designed. The results of this paper provide a useful map for the proper design of this type of parallel manipulator.
Modeling, Design and Analysis of a Robot System for Garment Inspection
Authors: Fung E. H. K. , Cheng Long , Wong Y. K. , Zhang X. Z. , Yuen C. W. M. , Wong W. K.
Published: July 2010

This paper presents the design and performance of a robot system that exerts a prescribed tension on fabrics to facilitate the inspection process. The robot system consists of a 3-DOF (degree-of-freedom) robotic hanger and an adaptive controller. In the hanger design, the second link is kept vertical, while that of the previous hanger has a redundant degree of freedom. In addition, this hanger has a shoulder link and a sleeve link that provide convenience for holding the garment. In the controller design, structure friction caused by joints and belt elasticity, which is non-linear in nature, are taken into consideration. Besides, the clothing stiffness also changes non-linearly with extension, which cannot be well handled by simple proportional-integral-derivative (PID) control. Due to these points, the fuzzy logic PID controller is chosen to deal with the non-linear features in this design. After establishing the system, the performance is analyzed by computer simulation, where different conditions are applied to compare fuzzy logic control with conventional PID control. The simulation results show that the fuzzy PID control method is effective in controlling the robot hanger and regulating the garment forces.
F-22 Lessons Learned: Line Replaceable Module (LRM) Electrical Connector—An Investigation of Vibration-Induced Contact Wear and Electro Static Discharge Hardening
Authors: Glista Stefan M. , Burns William F. , Lessard Briand
Published: July 2010

Flight Line Replaceable Modules (LRMs) are the foundation for modern day architectures in fighters such as the F-22. The 2-level maintenance concept (flight line to depot) reduces costs for spares and base level repair of circuit cards. However, this maintenance concept is predicated on the ability of the software to isolate failures down to the LRM or circuit card level. The types of failures that result from worn and corroded connectors result in large ambiguity groups; thus, making isolation to the circuit card level difficult. The vibration, thermal, humidity and corrosion environments of the F-22 are severe. Similarly, the ESD environment (for F-22 flight line maintenance) is severe because maintenance is performed without grounding straps or any special handling requirements. Hardware designed for use in this environment must be easily installed, capable of performing in a severe environment while maintaining high data rates without interruption. This paper identifies the F-22 risk reduction approach taken to mitigate the effects of the severe environments. The design & analytical approach taken during the program development phase offers important insight into the methods needed for predicting and analyzing hardware installation within the severe vibration and thermal environments commonly found in today’s fighter aircraft.
Experience of Designing and Manufacturing a BattleBot to Compete
Authors: Dong Janet , Dave Janak
Published: July 2010

Students working toward a baccalaureate degree in Mechanical Engineering Technology at the University of Cincinnati are required to complete a “Design, Manufacturing, and Test” senior capstone design project. One of these capstone design projects was to design and manufacture a battle robot to participate in the BotsIQ national competition. This robot was built to meet the BotsIQ 120 lb weight class specifications. A BattleBot is a robot which possesses fighting capabilities and competes against other BattleBots with the intent to disable them. The weapon is the main component of the BattleBots. BattleBots compete one on one and the winner is determined by the amount of damaged inflicted to the other using the weapon. In the 2007–2008 academic year, a team of four Mechanical Engineering Technology students at the University of Cincinnati built a BattleBot as their senior capstone design project. As with all capstone projects, expertise and knowledge acquired from their coursework and co-op were utilized. This project gave them an opportunity to showcase their abilities as well as develop additional skills needed to be successful in a team oriented business world. This team also enjoyed the personal satisfaction of working on a technically complex project from concept-to-design, manufacture, test, and compete against other university participants in the competition. This paper will describe students’ experiences in designing, manufacturing, and competing their robot in the national competition and team experience of the participants.
Effect of Microgrooved Surface and Surface Orientation on Spray Cooling Heat Transfer
Authors: Chen Dong-Fang , Tang Da-Wei , Hu Xue-Gong
Published: July 2010

Experiments were performed to investigate the flow structure and boiling heat transfer characteristics of water spray cooling on flat and microgrooved surfaces using a high-speed camera and a microscope. The heaters were made of cooper, with surface size of 2.0cm×7.4cm. Three orientations of the heater surfaces were selected: horizontal upward-facing, vertical, and horizontal downward-facing. A full-cone spray nozzle was placed normal to these heated surfaces. The heat transfer was directly measured using thermocouples within the heater. The experimental results show the bubble’s growth, coalescence along/between microgrooves, and break-up as wall heat flux reaches some higher values. It was found that the heat transfer for microgrooved surface is generally higher than that of flat surface at a given flow rate with the same surface orientation. The thermal performance of vertical microgrooved surface was highest at low temperatures; the thermal performance of the horizontal upward-facing was highest at higher wall temperature. The heat transfer performance for the horizontal downward-facing microgrooved surface had the highest critical heat flux (CHF).