bluuebunny/crossref_metadata_2025 huggingface dataset:
Intracranial hemorrhage in infants with cephalohematoma
Authors: Kim Heng Mi , Kwon Soon Hak , Park Sook Hyun , Kim Yong Sun , Oh Ki Won
Published: November 2013

Background

Intracranial hemorrhage (ICH) is a rare birth injury in term infants. Newborn infants with cephalohematoma (CH) associated with ICH, however, have frequently been found incidentally at Kyungpook National University Hospital; many of them had no neurological symptoms. The aim of this study was to evaluate the clinical manifestations of ICH in newborn infants with CH.

Methods

Newborn infants with CH in the neonatal intensive care unit were retrospectively evaluated. During period I (5 years), neuroimaging (brain computed tomography and magnetic resonance imaging) was performed when intracranial abnormalities were suspected. During period II (36 months) neuroimaging was performed when CH > 5 cm in diameter was present.

Results

During period I, seven out of 19 infants who underwent neuroimaging had ICH (36.8%) including two epidural hemorrhages (EDH). During period II, 18 out of 27 infants who underwent neuroimaging had ICH (66.7%), including two EDH. There was no significant difference in the clinical manifestations between infants with and without ICH. In 10 cases of CH accompanied with a linear skull fracture, nine had ICH, including all cases of ICH that needed intervention.

Conclusions

The association of ICH appears to be common in newborn infants with CH; particularly in infants with CH accompanied with a skull fracture, the rate of ICH was very high, and all cases of EDH requiring intervention were associated with skull fracture. Therefore, evaluation of accompanying skull fracture should be required in infants with CH, and, in cases of skull fracture, neuroimaging should be considered.
N‐terminal pro‐brain natriuretic peptide in the assessment of respiratory distress in term neonates
Authors: Markovic‐Sovtic Gordana , Kosutic Jovan , Jankovic Borisav , Bojanin Dragana , Sovtic Aleksandar , Radojicic Zoran , Rakonjac M. Zorica
Published: November 2013

Background

N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) is used as a biomarker to differentiate congestive heart failure from lung disease in adults and children. The clinical significance of its use in term neonates has not yet been extensively studied.

Methods

NT‐proBNP level was measured in 62 term neonates admitted for respiratory distress (RD): 38 with congenital heart disease (CHD) and 24 with pulmonary disease. The control group consisted of 28 healthy neonates. Findings of auscultation, chest radiography, Silverman–Anderson score and echocardiography were recorded for each patient. Blood samples for measuring NT‐proBNP were collected on admission, when blood sampling was indicated for the clinical management of the newborn.

Results

In the control group NT‐proBNP was significantly higher during the first week of life compared to the rest of the neonatal period (P < 0.001). The RD group, regardless of etiology, had significantly higher NT‐proBNP than the control group (P < 0.001). Neonates with more severe RD had significantly higher NT‐proBNP (P = 0.002). No significant difference was found between the RD group with CHD and those with pulmonary disease. Neonates with CHD and myocardial hypocontractility had significantly higher NT‐proBNP than those with normal contractility (P = 0.022).

Conclusion

Term neonates with RD have significantly higher NT‐proBNP than healthy neonates. A single measurement of NT‐proBNP level cannot be used as the sole biomarker for distinguishing between cardiac and pulmonary cause of RD in term neonates.
Photosensitized Damage Inflicted on Plasma Membranes of Live Cells by An Extracellular Generator of Singlet Oxygen—A Linear Dependence of A Lethal Dose on Light Intensity
Authors: Zarębski Mirosław , Kordon Magdalena , Dobrucki Jurek W.
Published: November 2013

We describe a study of the influence of a dose rate, i.e. light intensity or photon flux, on the efficiency of induction of a loss of integrity of plasma membranes of live cells in culture. The influence of a photon flux on the size of the light dose, which was capable of causing lethal effects, was measured in an experimental system where singlet oxygen was generated exclusively outside of live cells by ruthenium(II) phenantroline complex. Instantaneous, sensitive detection of a loss of integrity of a plasma membrane was achieved by fluorescence confocal imaging of the entry of this complex into a cell interior. We demonstrate that the size of the lethal dose of light is directly proportional to the intensity of the exciting light. Thus, the probability of a photon of the exciting light inflicting photosensitized damage on plasma membranes diminishes with increasing density of the incident photons.
Plexiform fibrohistiocytic tumor of bone
Authors: Yalcinkaya Ulviye , Uz Unlu Mehtat , Bilgen M. Sadik , Yazici Zeynep
Published: November 2013

Plexiform fibrohistiocytic tumor is an extremely rare soft tissue tumor with a low malignancy potential. The patient is usually a child or a young adolescent and the tumor is usually localized in the upper extremities. We report on a case of a 21‐year old male with a plexiform fibrohistiocytic tumor in the left fibula admitted to our hospital due to a swelling and pain in the left lower extremity. Radiologically a lytic lesion in the distal end of left fibula consistent with a non‐aggressive lesion with low biological activity was found. Treated with curettage, the specimen revealed plexiform proliferation of mononuclear histiocyte‐like cells, multinucleated osteoclast‐like cells, and spindle fibroblast‐like cells in variable proportions histopathologically. Immunohistochemical stains were positive for CD68 in scattered fashion in histiocytes and giant cells, and spindle like cells showed positivity for smooth muscle actin. Under electron microscopy, rough endoplasmic reticulum and collagen bundles in the spindle cells suggested fibroblastic differentiation. Also multiple large electron‐dense lysosomal granules in histiocytoid cells were found. Multinucleated giant cells exhibited osteoclast‐like appearance. All these findings suggested plexiform fibrohistiocytic tumor. Interestingly, the tumor was localized in bone. During the follow up for 27 months after the resection, there was no recurrence or metastasis.
Evaluating J‐integral from Displacement Fields Measured by Digital Image Correlation
Authors: Yoneyama S. , Arikawa S. , Kusayanagi S. , Hazumi K.
Published: November 2013

Path integral, domain integral and least squares methods for evaluating J‐integral from measured displacement fields for a power‐law hardening material are described in this paper. The values of the J‐integral are evaluated by applying the path and domain integral methods to the displacement fields obtained by elastoplastic finite element analysis and the displacement fields obtained through the measurement using digital image correlation. Results show that the values obtained by the domain integral method are slightly better than those by the path integral method, because the domain integral method efficiently uses the full‐field measurement data. The values of the J‐integral are also evaluated by the least squares method with the Hutchinson, Rice, and, Rosengren displacement fields. Results show that the J‐integral can be obtained by the least squares method simply and easily without any calculation of the integration. The J‐integral values obtained by the least squares method agree well with the values obtained using other methods. Because J‐integral can be evaluated easily by any method described in this paper, it is expected that these methods are applicable to various fracture problems during experimental evaluation of structural components.
Multiple copies of eukaryotic translation initiation factors in Brassica rapa facilitate redundancy, enabling diversification through variation in splicing and broad‐spectrum virus resistance
Authors: Nellist Charlotte F. , Qian Wei , Jenner Carol E. , Moore Jonathan D. , Zhang Shujiang , Wang Xiaowu , Briggs William H. , Barker Guy C. , Sun Rifei , Walsh John A.
Published: November 2013

Recessive strain‐specific resistance to a number of plant viruses in the Potyvirus genus has been found to be based on mutations in the eukaryotic translation initiation factor 4E (eIF4E) and its isoform, eIF(iso)4E. We identified three copies of eIF(iso)4E in a number of Brassica rapa lines. Here we report broad‐spectrum resistance to the potyvirus Turnip mosaic virus (TuMV) due to a natural mechanism based on the mis‐splicing of the eIF(iso)4E allele in some TuMV‐resistant B. rapa var. pekinensis lines. Of the splice variants, the most common results in a stop codon in intron 1 and a much truncated, non‐functional protein. The existence of multiple copies has enabled redundancy in the host plant's translational machinery, resulting in diversification and emergence of the resistance. Deployment of the resistance is complicated by the presence of multiple copies of the gene. Our data suggest that in the B. rapa subspecies trilocularis, TuMV appears to be able to use copies of eIF(iso)4E at two loci. Transformation of different copies of eIF(iso)4E from a resistant B. rapa line into an eIF(iso)4E knockout line of Arabidopsis thaliana proved misleading because it showed that, when expressed ectopically, TuMV could use multiple copies which was not the case in the resistant B. rapa line. The inability of TuMV to access multiple copies of eIF(iso)4E in B. rapa and the broad spectrum of the resistance suggest it may be durable.
The Sybtraps: Control of Synaptobrevin Traffic by Synaptophysin, α‐Synuclein and AP‐180
Authors: Gordon Sarah L. , Cousin Michael A.
Published: November 2013

Synaptobrevin II (sybII) is a key fusogenic molecule on synaptic vesicles (SVs) therefore the active maintenance of both its conformation and location in sufficient numbers on this organelle is critical in both mediating and sustaining neurotransmitter release. Recently three proteins have been identified having key roles in the presentation, trafficking and retrieval of sybII during the fusion and endocytosis of SVs. The nerve terminal protein α‐synuclein catalyses sybII entry into SNARE complexes, whereas the monomeric adaptor protein AP‐180 is required for sybII retrieval during SV endocytosis. Overarching these events is the tetraspan SV protein synaptophysin, which is a major sybII interaction partner on the SV. This review will evaluate recent studies to propose working models for the control of sybII traffic by synaptophysin and other Sybtraps (sybII trafficking partners) and suggest how dysfunction in sybII traffic may contribute to human disease.
Enriching the Pore: Splendid Complexity from Humble Origins
Authors: Field Mark C. , Koreny Ludek , Rout Michael P.
Published: November 2013

The nucleus is the defining intracellular organelle of eukaryotic cells and represents a major structural innovation that differentiates the eukaryotic and prokaryotic cellular form. The presence of a nuclear envelope (NE) encapsulating the nucleus necessitates a mechanism for interchange between the contents of the nuclear interior and the cytoplasm, which is mediated via the nuclear pore complex (NPC), a large protein assembly residing in nuclear pores in the NE. Recent advances have begun to map the structure and functions of the NPC in multiple organisms, and to allow reconstruction of some of the evolutionary events that underpin the modern NPC form, highlighting common and differential NPC features across the eukaryotes. Here we discuss some of these advances and the questions being pursued, consider how the evolution of the NPC has been constrained, and finally propose a model for how the NPC evolved.
Acute hepatitis B in blood donors over a 5‐year period in England and North Wales: who is getting infected?
Authors: Rosenberg Gillian K. , Lattimore Sam , Brailsford Susan R. , Hewitt Patricia E. , Tettmar Kate I. , Kitchen Alan D. , Ijaz Samreen , Tedder Richard S.
Published: November 2013

Background

Hepatitis B virus (HBV) remains the infection most frequently recognized by donation testing in blood donors. It is usually a persistent infection and mostly reflects the country of origin of the donor or the donor's family. There are, however, a minority of acute infections and this study undertook their phylogenetic analysis to determine the likely source of infection.

Study Design and Methods

Plasma samples from 11 donors donating between July 2005 and June 2010, whose test results revealed recent infection with hepatitis B, were available for further analysis. Plasma DNA was extracted, amplified, sequenced, and analyzed phylogenetically. Donor and virus characteristics were compared with the overall demography of all hepatitis B–infected donors attending over the same period.

Results

Three of the 11 individuals were first‐time donors. Nine were male, of whom eight were white British. All had serum markers of very recent infection. Only two indicated known HBV exclusion risk factors at postdonation discussion not declared previously. Genotype A was present in seven, Genotype B in two, and Genotype C in two, contrasting with the pattern in persistently infected persons in the United Kingdom. A single A2 strain was identified in six of the white British male donors, suggesting epidemiologic linkage.

Conclusion

Phylogenetic analysis of HBV‐infected donors performed in real time can potentially lead to identification of undeclared risk factors that donor health questionnaires may fail to identify.
Purinergic control of vascular tone in the retina
Authors: Kur Joanna , Newman Eric A.
Published: November 2013

Key points

The blood supply to the CNS is controlled by the tone of arteries and arterioles. However, little is known about purinergic regulation of vascular tone in the CNS.

We have investigated purinergic control of vascular tone in the in vivo rat retina.

Reducing endogenous ATP levels by enzyme degradation and inhibiting purinergic signalling with P2X receptor antagonists decreases the tone of retinal arterioles. Raising ATP levels increases vessel tone.

Experiments using fluorocitrate to poison the metabolism of glial cells suggest glia are a source of the ATP that tonically constricts retinal vessels.

The results suggest a novel mechanism of local control of vascular tone through activation of vascular smooth muscle cell P2X receptors.

Purinergic control of vascular tone in the CNS has been largely unexplored. This study examines the contribution of endogenous extracellular ATP, acting on vascular smooth muscle cells, in controlling vascular tone in the in vivo rat retina. Retinal vessels were labelled by i.v. injection of a fluorescent dye and imaged with scanning laser confocal microscopy. The diameters of primary arterioles were monitored under control conditions and following intravitreal injection of pharmacological agents. Apyrase (500 units ml−1), an ATP hydrolysing enzyme, dilated retinal arterioles by 40.4 ± 2.8%, while AOPCP (12.5 mm), an ecto‐5′‐nucleotidase inhibitor that increases extracellular ATP levels, constricted arterioles by 58.0 ± 3.8% (P < 0.001 for both), demonstrating the importance of ATP in the control of basal vascular tone. Suramin (500 μm), a broad‐spectrum P2 receptor antagonist, dilated retinal arterioles by 50.9 ± 3.7% (P < 0.001). IsoPPADS (300 μm) and TNP‐ATP (50 μm), more selective P2X antagonists, dilated arterioles by 41.0 ± 5.3% and 55.2 ± 6.1% respectively (P < 0.001 for both). NF023 (50 μm), a potent antagonist of P2X1 receptors, dilated retinal arterioles by 32.1 ± 2.6% (P < 0.001). A438079 (500 μm) and AZ10606120 (50 μm), P2X7 antagonists, had no effect on basal vascular tone (P = 0.99 and P = 1.00 respectively). In the ex vivo retina, the P2X1 receptor agonist α,β‐methylene ATP (300 nm) evoked sustained vasoconstrictions of 18.7 ± 3.2% (P < 0.05). In vivo vitreal injection of the gliotoxin fluorocitrate (150 μm) dilated retinal vessels by 52.3 ± 1.1% (P < 0.001) and inhibited the vasodilatory response to NF023 (50 μm, 7.9 ± 2.0%; P < 0.01). These findings suggest that vascular tone in rat retinal arterioles is maintained by tonic release of ATP from the retina. ATP acts on P2X1 receptors, although contributions from other P2X and P2Y receptors cannot be ruled out. Retinal glial cells are a possible source of the vasoconstricting ATP.
Contribution Ratio Study of Fuel Alcohol and Gasoline on the Alcohol and Hydrocarbon Emissions of a Gasohol Engine
Authors: Wei Yanju , Wang Kun , Wang Wenrui , Liu Shenghua , Yang Yajing
Published: November 2013

Methanol (CH3OH) and ethanol (C2H5OH) are generally called alcohol. They can be mixed with gasoline to fuel SI engine. The fuel blends of alcohol and gasoline are named gasohol. Alcohol emission characteristics and the contributions of fuel on hydrocarbon (HC) emission were experimentally investigated on a three-cylinder, electronic controlled, spark ignition JL368Q3 engine when it ran on 10 (v/v) %, 20 (v/v) %, and 85 (v/v) % methanol/gasoline and ethanol/gasoline fuel blends. Experimental results show that, the value of alcohol emission rates (g alcohol emission per kg alcohol fuel, g/kg.) is a decreasing exponential function of exhaust temperature with high correlation; regardless of the alcohol fraction in fuel blends, the CH3OH emission rate is no more than 8%, while that of C2H5OH no more than 35%. The emission rate of nonalcohol HC was one grade higher than the alcohol emission rate; the minimum HC emission rate occurs at middle and high engine loads, it is around 40% for methanol/gasoline blends and about 50% for ethanol/gasoline blends. Gasoline is the main source of HC emission of gasohol engine, methanol contributes no more than 8% while ethanol no more than 25% on HC emission.
Machining of VP20ISOF Steel With Resharpened Carbide Tools in End Milling
Authors: Moura Ricardo Ribeiro , Machado Álisson Rocha
Published: November 2013

The main objective of the present work is to determine the performance of resharpened integral coated cemented carbide end milling tools. Tools as new and after they have been resharpened were tested, during machining of hard steel used in the mold and die industry. The coatings used were TiAlN and AlCrN. The cutting speed was varied, keeping the depth of cut, the cutting width and the feed per tooth constants. Tests were carried out dry. A 23 factorial design was used, considering the following factors (and levels): cutting speed (80 and 100 m / min), tool coating (TiAlN and AlCrN) and the tool condition (new and reground). The output parameter considered is the tool life (wear rate). At the end of the tool life the wear mechanisms were analyzed within a Scanning Electron Microscopy - SEM. The results showed that in general the AlCrN coated tools outperformed the TiAlN. The performance of resharpened tools was very similar to the new tools, and statistically there is no significant difference between their tool lives.
Characterization of Flow Stress for Commercially Pure Titanium Subjected to Electrically-Assisted Deformation
Authors: Magargee James , Morestin Fabrice , Cao Jian
Published: November 2013

Uniaxial tension tests were conducted on thin commercially pure titanium sheets subjected to electrically-assisted deformation using a new experimental setup to decouple thermal-mechanical and possible electroplastic behavior. The observed absence of stress reductions for specimens air-cooled to near room temperature motivated the need to reevaluate the role of temperature on modeling the plastic behavior of metals subjected to electrically-assisted deformation, an item that is often overlooked when invoking electroplasticity theory. As a result, two empirical constitutive models, a modified-Hollomon and the Johnson-Cook models of plastic flow stress, were used to predict the magnitude of stress reductions caused by the application of constant DC current and the associated Joule heating temperature increase during electrically-assisted tension experiments. Results show that the thermal-mechanical coupled models can effectively predict the mechanical behavior of commercially pure titanium in electrically-assisted tension and compression experiments.
Bioprinting Induced Cell Damage in Cellular Micro-Fluidic Channel Fabrication
Authors: Yu Yin , Ozbolat Ibrahim T.
Published: November 2013

Bioprinting, or layer by layer additive tissue fabrication, is a revolutionary concept recently emerged as an interdisciplinary effort to produce three-dimensional living organ for clinical application. Among many challenges, it was agreed that inclusion of vascular system is critical for maintaining the viability and functionality of relatively thick 3D bioprinted tissue constructs. Our previous research addressed the printability of novel vessel-like micro-fluidic channels with alginate hydrogel and co-axial nozzles. Here, we further investigated the influence of bioprinting parameters on cartilage progenitor cells (CPCs) survival during and post printing. The results of this study revealed that quantifiable cell death could be induced by varying dispensing pressure, co-axial nozzle geometry, biomaterial concentration. However, damaged cells were able to recover during incubation, as well as undergo proliferation to certain extend. These findings may serve as a guideline for optimizing our system as well as predict cell damage in future studies.
Cutting Force of Hollow Needle Insertion in Soft Tissue
Authors: Tai Bruce L. , Wang Yancheng , Shih Albert J.
Published: November 2013

This paper presents a 3-D finite element model (FEM) using cohesive zone (CZ) concept to simulate the hollow needle insertion and identify the change in cutting force. CZ is a FEM technique that integrates the fracture mechanics based on surface energy and has often used in analysis of crack propagation. Experiments of needle insertion into the soft polyvinyl chloride (PVC) phantom tissue were conducted using two types of needle (bias bevel and lancet) under a constant speed to identify friction and cutting forces. Using the CZ concept, a thin layer of FEM is built to observe the tissue flow and cutting force along the needle cutting edge during insertion. Both experimental observation and modeling results show higher cutting force for the lancet tip due to smaller rake angle along the cutting edge. This FEM approach has demonstrated the potential as being an analysis tool for hollow needle insertion.
An Investigation on Electrochemical Discharge Micro-Drilling of Glass
Authors: Razfar Mohammad Reza , Ni Jun , Behroozfar Ali , Lan Shuhuai
Published: November 2013

Electrochemical Discharge Machining (ECDM) as an innovative spark-based micromachining method has been successfully applied for fabricating micro-holes in non-conductive brittle materials such as glass. However, the effects of influencing parameters for attaining accurate structures and dimensions remain to be explored. This paper attempts to analyze the effects of process parameters including applied voltage, tool immersion depth and electrolyte concentration on process outputs such as radial overcut (ROC), material removal rate (MRR), heat affected zone (HAZ) thickness and roundness error (RE) of the holes. In this regard, a set of experiments based on response surface experiment design method were conducted on soda lime glass. The relevant experimental data were used to establish mathematical models for process outputs using the response surface methodology (RSM). The obtained results show that applied voltage significantly increases the ROC, MRR, HAZ and RE. Also, electrolyte concentration has the same effects on mentioned outputs except the ROC. In addition, greater tool immersion depth decreases the MRR and HAZ thickness. The adequacy of the developed mathematical models was also evaluated by an analysis of variance (ANOVA) test. The relevant results show the capability of the proposed approach to investigate the ECDM process of glass.
Prediction of Distortion in Quenching-Tempering Processes for a SM256 Steel Component With Internal Thread
Authors: Nie Zhenguo , Rong Yiming (Kevin) , Wang Gang
Published: November 2013

A steel component with internal thread has a few slight distortions when it undergoes quenching-tempering processes. These small distortions affect assembly severely in the precision engineering. Using FEA software with its user subroutines, the position and contour of distortions which will be confirmed by subsequent experimental measurement are simulated. This result reasonably explains the assemble difficulty in enterprise manufacturing, and then lots of suggestions are given for manufacturing improvements.
Effects of Ultrasonic Vibration-Assisted Pelleting on Sugar Yield in Biofuel Manufacturing With Different Pretreatment Methods
Authors: Kennedy Elizabeth , Zhang Pengfei , Zhang Qi , Pei Z. J. , Wang Donghai
Published: November 2013

There are many concerns taking place due to the reliability and sustainability of petroleum-based liquid transportation fuels. The importance of finding an alternative fuel source to the petroleum-based fuels is in high demand. One promising alternative is cellulosic biofuels that offer numerous benefits for the environment. However, there are some obstacles in the way of manufacturing the cellulosic biofuels at a large scale and doing so cost effectively. One obstacle is the low sugar yield of biomass in enzymatic hydrolysis, leading to low efficiency in biomass-biofuel conversion and thus high conversion costs. Pretreatment of biomass is required to achieve high sugar yield in enzymatic hydrolysis. Dilute acid pretreatment and hot water pretreatment can effectively increase the sugar yield, but they usually involve high temperature or excessive use of acid, making pretreatment one of the most costly process in cellulosic biofuel manufacturing. This study investigated effects of ultrasonic vibration-assisted pelleting on the sugar yield of biomass pretreated by the two pretreatment methods. Results showed that, for both pretreatment methods, pellets produces higher sugar yield than particles. Furthermore, at the same pretreatment temperature, the water-pretreated pellets produced higher sugar yield than acid-pretreated particles.
Microcellular Injection Molding of Gas-Laden Pellets Using Nitrogen (N2) and Carbon Dioxide (CO2) as Co-Blowing Agents
Authors: Sun Xiaofei , Turng Lih-Sheng , Gorton Patrick J. , Nigam Pankaj , Buell Sezen
Published: November 2013

A novel combination approach to producing quality foamed injection molded parts has been investigated. By combining extruded, gas-laden pellets with microcellular injection molding, the processing benefits and material characteristics of using both N2 and CO2 blowing agents can be realized, thus yielding features superior to that of using either N2 or CO2 alone. Using an optimal content ratio for the blowing agents, as well as the proper sequence of introducing the gases, foamed parts with a much better morphology can be produced. In particular, extruding N2 gas-laden pellets, followed by microcellular injection molding with higher amounts of CO2, produces a cellular structure that is very fine and dense. In this paper, the theoretical background is discussed and experimental results show that this combined approach leads to significant improvements in foam cell morphology for low density polyethylene (LDPE), polypropylene (PP), and high impact polystyrene (HIPS) using two different mold geometries.
Development and Implementation of Cloud Manufacturing: An Evolutionary Perspective
Authors: Liu Yongkui , Zhang Lin , Tao Fei , Wang Long
Published: November 2013

Cloud manufacturing (CMfg) is a new service-oriented networked manufacturing paradigm. In a CMfg system, the operator of CMfg platform provides services for resource providers to publish their idle manufacturing resources and for resource demanders to access the resource pool on-demand. To uncover the underlying mechanism supporting the development and implementation of CMfg, a model of CMfg system is proposed by abstracting the CMfg operator as a third party and modeling the relationships of CMfg users using the scale-free network. We investigate the effect of saturation degree of manufacturing task and find that there exists an intermediate value of the parameter optimally favoring the participation of enterprises in CMfg. We also study the charging issue. The obtained result shows that the CMfg system is robust with respect to resource charge. Finally, we discuss the future work and conclude the paper.
Experimental Investigation and Modeling of Milling Burrs
Authors: Niknam Seyed Ali , Songmene Victor
Published: November 2013

The burr formation is one of the most common and undesirable phenomenon occurring in machining operations which reduces assembly and machined part quality. Therefore, it is desired to eliminate the burrs or reduce the effort required to remove them. This paper presents the results of an experimental study and describe the influence of cutting parameters on slot milling burrs, namely top burrs and exit burrs. Statistical methods are also used to determine the controllability of each burr. A computational model is then proposed to predict the exit up milling side burr thickness based on cutting parameters and material properties such as yield strength and specific cutting force coefficient that are the only unknown variables in the model. The proposed computational model is validated using experimental results obtained during slot milling of 2024-T351 and 6061-T6 aluminium alloys.
A New Approach for a Simulation-Based Prediction of Torsional Chatter in Deep Hole Drilling With Extra-Long Twist Drills
Authors: Abele E. , Schäfer D.
Published: November 2013

Numerous investigations work on torsional chatter vibrations in drilling. Particularly in terms of productivity, torsional chatter is detrimental because of a reduction of tool life and an undesirably high level of noise emissions due to the increased process dynamics. To achieve a deeper understanding of the process dynamics, a new numerical simulation model was developed to predict torsional chatter for extra-long twist drills. It is used to determine the influence of numerous factors such as cutting parameters, drill torsional stiffness, rotary moment of inertia and torsional-axial coupling. In this paper, the general structure of the model and the tool model is presented.
Comparison of Electrically-Assisted and Conventional Friction Stir Welding Processes by Feed Force and Torque
Authors: Potluri Hemanth , Jones Joshua J. , Mears Laine
Published: November 2013

The process of friction stir welding involves high tool forces and requires robust machinery; the forces involved make tool wear a predominant problem. As a result, many alternatives have been proposed in decreasing tool forces such as laser assisted friction stir welding and ultra-sound assisted friction stir welding. However, these alternatives are not commercially successful on a large scale due to scalability and capital/maintenance costs.

In an attempt to reduce forces in a cost-feasible manner, electrically-assisted friction stir welding (EAFSW) is studied in this work. EAFSW is a result of applying the concept of electrically-assisted manufacturing (i.e., passing high direct electrical current through a workpiece during processing) to the conventional friction stir welding process. The concept of EAFSW is a relatively new adaptation of conventional frictional stir welding, which is well established. The expected benefits are reduction in the feed force and torque, which allow for improved processing productivity as well as the possibility for deeper penetration of the weld.
Novel High Pressure Sealing System for Tube Hydroforming Operations
Authors: Wagner Scott W. , Ng Kenny , Emblom William J. , Camelio Jaime A.
Published: November 2013

The tube hydroforming (THF) process is a metal forming process that uses a pressurized fluid as the forming mechanism. Recently, this process has increased in popularity in the automotive industry as a method to reduce the number of required components and consolidate parts which can substantially reduce the overall automobile weight. This reduction in weight is a currently pursued method for improving the vehicles fuel economy.

At the micro scale, hydroformed tubes have the potential to offer additional benefits with possible uses in medical and MEMS (Microelectromechanical systems) applications. However, this can be a challenge when the forming materials have small mating features. In many macro scale tube hydroforming processes the forming fluid is supplied to the tubes by a tapered filling nozzle inserted inside the inner diameter of the tubes. When considering forming tubes with sub-millimeter features, this poses a significant challenge.

This paper explores the design of a new method for creating the required high pressure seal. Specifically, this seal is made on the outside surface of the tube by using a flexible encompassing rubber gasket and two proprietary designed seal cavities. In this study, stainless steel 304 micro tubes of varying outer diameters (1.0 mm and 2.1 mm) and thickness were tested.
Characterizing Energy Consumption of the Injection Molding Process
Authors: Madan Jatinder , Mani Mahesh , Lyons Kevin W.
Published: November 2013

Presently available systems for sustainability assessment do not fully account for aspects related to a product’s manufacturing. In an effort to make more sustainable decisions, today’s industry seeks reliable methods to assess and compare sustainability for manufacturing. As part of the Sustainable Manufacturing program at the National Institute of Standards and Technology (NIST), one of our objectives is to help develop the needed measurement science, standards and methodologies to evaluate and improve sustainability of manufacturing processes. As a first step towards developing standard reference sustainability characterization methodologies for unit manufacturing processes, in this paper we focus on injection molding with energy as the sustainability indicator. We present a science-based guideline to characterize energy consumption for a part manufactured using the injection molding process. Based on the study, we discuss the selection of process parameters and manufacturing resources, determination of cycle time, theoretical minimum energy computations, and estimated energy computations for characterizing the injection molding process.
Analytical Design and Implementation of a Uniform Pressure Actuator for Electromagnetic Forming and Welding
Authors: Thibaudeau E. , Kinsey B. L.
Published: November 2013

Lightweight sheet metal components and assemblies formed and welded electromagnetically can be implemented in various industries such as automotive, aerospace, and electronics. Past applications and modeling of Electromagnetic Forming (EMF) and Magnetic Pulse Welding (MPW) have typically focused on crimping and expansion of tubular workpieces. While some Finite Element Analysis (FEA) packages exist that are capable of modeling these processes, there is a lack of simplified analytical modeling efforts, especially for sheet metal workpieces. Analytical modeling is attractive for its simplicity and cost in effectively determining e.g., an optimal coil design. In this paper a coil design and analysis procedure developed at The Ohio State University is modified and extended through an analytical model and FEA. The coil, named a Uniform Pressure Actuator (UPA), offers increased forming efficiency and repeatability, as well as a robust design. Coil design parameters such as the number of turns and conductor cross section are determined for a given workpiece. Magnetic pressure applied to the workpiece and workpiece velocity are predicted to ensure impact velocities are sufficient for MPW. A coil was constructed based on the analyses, and experimental results are compared to the analytical predictions for both electrical characteristics and workpiece velocity.
Numerical Modeling of Specific Energy Consumption in Machining Process
Authors: Li Tonghui , Yuan Chris
Published: November 2013

Prediction and estimation of energy consumption of machining process are important for the optimization of the machining process and the environmental impact of manufacturing. Two energy consumption models are proposed in this paper. A novel numerical model is presented to roughly estimate the specific energy consumption (SEC) of a machining process based on the nameplate spindle power of the machine and the material removal rate (MRR). This model is validated and analyzed by experimental data from a variety of sources. The application range of the proposed model has been investigated. Another accurate SEC model, which is based on a specific machine and machine tool, is established for accurate energy consumption prediction. The accurate model is tested to have a confidence range of 97%.
Synthesis and Characterization of High Performance Polymer Nanocomposite Using Carbon Nanotubes as Fillers
Authors: Thangapandian N. , Balasivanandha Prabu S. , Paskaramoorthy R.
Published: November 2013

In this work, the chemical vapour deposition (CVD) method is used for the production of carbon nanotubes (CNTs). The catalyst, Fe/MgO, was prepared through sonication technique. It was heated to 600 °C for 6 hours and this was used as the template for growing the CNTs using acetylene as carbon precursor. The deposited CNTs were separated by acid treatment followed by air oxidation. The purified CNTs were examined by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The CNTs were observed to have a multi-wall structure with the diameter in the range of 10–20 nm. These multiwalled carbon nanotubes (MWCNTs) were used as filler material in an epoxy matrix. Sonication technique was used to achieve uniform dispersion of CNTs within the matrix. The CNT/epoxy nanocomposite was cured at a temperature of 100 °C for 3 hours. Tensile strength, flexural strength, fire retardant properties and surface conductivity were studied. The results reveal that addition of MWCNTs to the epoxy promotes substantial improvement to the above mentioned properties.
VIM Testing of a Paired Column Semi Submersible
Authors: Zou Jun , Poll Philip , Roddier Dominique , Tom Nathan , Peiffer Antoine
Published: November 2013

This paper summarizes VIM towing test results of Houston Offshore Engineering’s Paired-Column Semisubmersible (PC Semi) platform that was performed at the UC Berkeley towing tank. The PC semi configuration is different from a conventional Deep Draft Semi (DD Semi) in three aspects, 1) 8 columns vs. 4 columns; 2) rectangle column vs. square column; 3) larger column slenderness ratio. Typically, a larger column slenderness ratio may result in more pronounced VIM. Since VIM significantly affects mooring and riser strength and fatigue, it is crucial to explore the VIM response characteristics of the PC Semi configuration.

VIM has been characterized as a difficult subject with a complicated structural-hydrodynamic interaction. The physical mechanics is generally less well understood and numerical prediction is generally less reliable. Model testing has become an important and widely accepted design tool to derive reliable A/D envelops and drag coefficients.

This project builds on the VIM testing experiences obtained in Finnigan and Roddier (2007), which showed that VIM testing at small scale is only slightly conservative. A scale factor of 1:160 was used in the present tests. The Reynolds Number for the tests varied from 15,000 to 30,000 depending on the towing speeds. This manuscript provides some details on the test setup and overall program, and highlights the key results of the tests.
Estimation of Onsite Wave Parameters From the WindFloat Platform
Authors: Peiffer Antoine , Tom Nathan , Cermelli Christian , Roddier Dominique
Published: November 2013

The WindFloat is a semi-submersible floating foundation supporting multi-megawatt wind turbines. A full-scale 2MW WindFloat demonstration unit was installed off the coast of Portugal in October 2011. Many instruments are installed on this prototype to measure the environmental conditions and the response of the platform at the site. The first section of the paper focuses on the validation of the wave measurements obtained from two radar-based wave probes onboard the platform. The wave elevation at the site is reconstructed and typical wave statistics are computed. The results are compared and validated with independent buoy measurements close to site. The second section of the paper presents estimates of prevailing wave direction and directional wave spectra based on platform motions. These results are also benchmarked with onsite buoy measurements.
Global Trends in Extreme Wind Speed and Wave Height
Authors: Young I. R. , Zieger S. , Vinoth J. , Babanin A. V.
Published: November 2013

Satellite observations of the ocean surface provide a powerful method for acquiring global data on wind speed and wave height. Radar altimeters have now been in operation for more than 25 years, providing a reasonably long term data set with global coverage. This paper presents data from a fully calibrated and validated altimeter dataset. The dataset provides the basis for obtaining a global perspective of a number of parameters critical to ocean engineering design, ship operations and global climate change. Analysis of the data provides ocean climatology of mean monthly values of wind speed and wave height useful for ship operations. The data set is also sufficiently long to provide extreme value (i.e. 100-year return period) estimates of wind speed and wave height. The paper presents such values and describes the approaches most appropriate to obtain statistically significant extreme value estimates from such satellite data. With a data set of this length, it is possible to investigate whether there have been statistically significant changes in the wind and wave climates over the period. Careful trend analysis of the extensive data set shows that there has been a statistically significant increasing trend in mean wind speed over the period. The corresponding increase in wave height is less clear. There is also evidence to suggest that extreme wind speeds and wave heights are increasing and the data set is analysed to investigate these trends. The paper clearly shows the value of this dataset and its application to a range of engineering problems.
Utilization of Piping Inspection Data for Continuous Improvement: A Methodology to Visualize Coverage and Finding Rates
Authors: Ratnayake R. M. Chandima
Published: November 2013

Piping inspection in Oil and Gas (O&G) production and process facilities (P&PFs) is traditionally set up by dividing the overall piping components into corrosion loops (CLs) reflecting similar corrosion (i.e. corrosion due to chemical or electro-chemical reaction and/or erosion-corrosion) environment and process conditions. Each CL is comprised of a few or several wall thickness measurement locations (WTMLs). The WTMLs are typically identified for each WTML ‘feature’ (e.g. straight section of a spool, bend, tee, weld, end cap, etc.) in a CL. Generally, inspection planning decisions regarding WTMLs are prioritized based on the results of risk based inspection (RBI) analysis. However, the degradation behavior is continuously changing due to the change in product and process conditions during the maturity of O&G production wells.

This manuscript illustrates a methodology to visualize inspection coverage and corresponding defect finding rates (DFRs) for different WTML features in a selected sub-system of an oil and gas production and process facility. The suggested methodology aids the visualization of DFRs pertaining to different WTMLs, enabling inspection planners to assign inspection recommendations to the right location at the right time, minimizing ad hoc work. The approach also enables feedback to be provided to the plant inspection strategy (PIS), depending on the corresponding production field and P&PF, whilst reducing the cost of inspection to the asset owner by the minimization of ad hoc inspection recommendations.
The Effect of Material Nonlinearity on the Dynamics of Hull/Mooring Coupled System
Authors: Qian Jiayu , Sun Liping , Song Linfeng
Published: November 2013

The dynamics of a turret-moored FPSO with 12 catenary chain-steel wire-chain mooring lines are studied to investigate the influence of the hull/mooring coupled system from both linear and nonlinear stiffness of steel wire. The two simulated results are compared with experimental statistics, it indicated that the results using nonlinear stiffness are slightly larger than using linear stiffness and closer when compared with the experimental statistics. Then it illustrates that the polynomial approximation of nonlinearity for steel wire is applicable. The difference between linear and nonlinear results of steel wire is not apparent due to steel wire doesn’t belong to the viscoelastic material. This paper also researches the motion of FPSO with taut chain-polyester-chain mooring lines because polyester rope has viscoelastic properties. The results are unstable when using lower and upper linear stiffness in the time-domain simulation. But the dynamic response of FPSO is good by nonlinear stiffness. Thus, the nonlinear elastic method should be used in engineering works to decrease the damaged risk of the structure.
Mechanical Integrity of Forge Welded Connectors
Authors: Jacobsen Terje Berg , Salberg Bjarne , Moe Per Thomas , Liu Junyan
Published: November 2013

Shielded Active Gas Forge Welding (SAG-FW) is a solid state welding process for metal pipes, rods and other elongate products. As a part of an extensive qualification programme for SAG-FW for casing applications a series of welds have been completed for the pipe steel quality Vallourec & Mannesmann VM50. While the microstructure of the base material (BM) is tempered martensite, both natural cooling and quench-tempered microsturctures were evaluated in order to assess the need for post-weld heat treatment (PWHT). Forge welds were subjected to careful and independent metallurgical analysis and mechanical testing by Det Norske Veritas (DNV). For as-welded specimens the heat affected zone (HAZ) consists of ferrite and pearlite. Hardness values for the HAZ are 160 HV10 while for the base material inner and outer wall are 150 and 175 HV10 respectively. As-welded tensile tests show a drop in yield from 390 to 370 MPa. Charpy testing of the welds at −20°C reveals a fully ductile structure with toughness of 150 J. The HAZ is entirely in the region with increased wall thickness.

In an extended study of mechanical properties of the VM50 forge welds results from a notched tensile test were used to determine the damage parameters for the Complete Gurson Model (CGM) using finite element modeling for calibration. In order to evaluate the quality of the damage model Single Edge Notched Bending (SENB) tests were performed and studied using finite element models. The toughness of the as-welded weld is moderately reduced due to welding, but it remains ductile with high fracture resistance. The moderate reduction of fracture resistance can be explained by microstructure change.
The Use of Additive Manufacturing Techniques in the Construction of Model-Scale Propellers
Authors: Garvin Matthew , Islam Mohammed , Molyneux David , Herrington Paul
Published: November 2013

Historically, it has been expensive for model test basins to supply custom model-scale propellers for ship propulsion experiments, due to the high cost of traditional propeller fabrication methods. This paper presents a new method of manufacturing model propellers in a cost effective and time efficient manner.

A new computer aided design tool has been developed to quickly develop propeller geometry, which can then be built using additive manufacturing processes. These processes reduce the cost of manufacturing propellers by an order of magnitude compared to machined metal propellers.

The results of a study comparing propeller open water and self-propulsion experiments using traditional metal propellers to newly developed plastic propellers are presented. This study also includes an evaluation of the effect of surface roughness on the open water performance coefficients. The measured propulsive performance coefficients of the plastic propellers were within 2% of that of geometrically similar metal propellers with the same blade roughness.