bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of transient elastography in patients with HIV–HCV coinfection: A systematic review and meta‐analysis
Authors: Njei Basile , McCarty Thomas R. , Luk Jeffrey , Ewelukwa Oforbuike , Ditah Ivo , Lim Joseph K.
Published: March 2016

Background and Aim

Patients with HIV‐hepatitis C virus (HCV) coinfection progress towards liver fibrosis and cirrhosis more rapidly compared with HCV mono‐infected individuals. This necessitates an accurate assessment of liver stiffness with transient elastography to guide treatment.

Methods

Searches of PubMed, EMBASE, Web of Science, and the Cochrane Library databases were performed through January 2016 to assess the diagnostic accuracy of transient elastography for liver stiffness in the HIV–HCV population. Included studies were analyzed according to the Cochrane DTA Working Group methodology. Bivariate and hierarchical models were used to compute pooled sensitivity and specificity. Positive and negative likelihood ratios were also determined. A Fagan nomogram was constructed. Meta‐regression analysis was performed with assessment of publication bias using Deeks' funnel plot asymmetry testing.

Results

A total of six studies (n = 756) met the inclusion criteria. The diagnostic accuracy of elastography for the diagnosis of moderate (≥F2) fibrosis was 88% (95% confidence interval [CI], 0.85–0.90). The pooled sensitivity and specificity of moderate fibrosis was 97% (95% CI, 0.82–0.91) and 64% (95% CI, 0.45–0.79), respectively. The diagnostic accuracy of elastography for the assessment of cirrhosis was 94% (95% CI, 0.91–0.95). The pooled sensitivity and specificity for cirrhosis was 90% (95% CI, 0.74–0.97) and 87% (95% CI, 0.80–0.92), respectively. Meta‐regression analysis demonstrated that CD4 cell count did not impact diagnostic accuracy of elastography.

Conclusions

Transient elastography is a noninvasive imaging modality with excellent ability to assess for cirrhosis in patients with HIV–HCV coinfection.
Estimation of Waste Battery Generation and Analysis of the Waste Battery Recycling System in China
Authors: Song Xiaoxu , Hu Shanying , Chen Dingjiang , Zhu Bing
Published: March 2016

China produces and consumes a large amount of batteries annually, which leads to many waste batteries needing to be recycled. The collection and recycling system of primary, alkaline secondary, and lithium‐ion secondary batteries in China is particularly poor, and waste battery recycling enterprises generally sustain economic losses if they solely use waste batteries as raw materials. Increasing the profits of waste battery recycling systems is a key problem that needs to be considered. This article quantitatively analyzes waste battery generation in China by using annual sales data and probable lifetime distribution of various batteries. The results show that the rapid growth of battery usage has led to an increased generation of waste batteries and the percentage of different types of waste batteries is changing over time. In 2013, the total quantity of all waste batteries in the medium lifetime scenario reached 570 kilotons, of which primary, alkaline secondary, and lithium‐ion secondary waste batteries accounted for approximately 36%, 28%, and 35%, respectively. Based on a real‐world case study of a typical domestic waste battery recycling enterprise in China, material flow analysis and cost‐benefit analysis were conducted to study the development of the recycling process of comingled waste batteries. Through scenario analysis, we conclude that increasing the use of waste batteries as raw materials and the recycling of other materials that are less valuable reduces the profits of the waste battery recycling enterprise. Higher profits can be achieved by adding the production of high value‐added downstream products and government support. At the same time, the essential role of the government in developing a waste battery recycling system was identified. Finally, relevant suggestions are made for improvements in both the government and enterprise sectors.
Behavioural interventions for sleep problems in people with an intellectual disability: a systematic review and meta‐analysis of single case and group studies
Authors: Priday L. J. , Byrne C. , Totsika V.
Published: March 2016

Background

Behavioural interventions are frequently used to address sleep problems in people with intellectual disabilities (ID). The current study aimed to systematically review evidence on the efficacy of behavioural interventions for children and adults with ID and sleep problems.

Method

Electronic and hand searches identified seven studies for inclusion (N = 169). Standardised mean difference effect sizes (d) were calculated for group studies (N = 4). Non‐overlap effect sizes (Tau‐U) were calculated for single case experimental design studies (SCEDs;N = 3).

Results

A large effect size (weightedd = 0.923, confidence interval: 0.705 to 1.151) across group studies indicated large improvements in sleep problems following behavioural intervention. Effect size across SCEDs (weighted Tau‐U: 0.528, confidence interval: 0.351 to 0.705) indicated a 53% improvement compared with baseline. Sleep initiation and sleep maintenance problems showed significant improvements post‐intervention. Follow‐up effects were less consistent across study designs and suggested that some sleep problems maintain gains better than others.

Conclusion

Meta‐analytic evidence from group and SCEDs can provide complementary information about efficacy. Findings propose that behavioural interventions are a promising evidence‐based practice for improving sleep problems in people with ID.
Methamphetamine compromises gap junctional communication in astrocytes and neurons
Authors: Castellano Paul , Nwagbo Chisom , Martinez Luis R. , Eugenin Eliseo A.
Published: March 2016

Methamphetamine (meth) is a central nervous system (CNS) stimulant that results in psychological and physical dependency. The long‐term effects of meth within the CNS include neuronal plasticity changes, blood–brain barrier compromise, inflammation, electrical dysfunction, neuronal/glial toxicity, and an increased risk to infectious diseases including HIV. Most of the reported meth effects in the CNS are related to dysregulation of chemical synapses by altering the release and uptake of neurotransmitters, especially dopamine, norepinephrine, and epinephrine. However, little is known about the effects of meth on connexin (Cx) containing channels, such as gap junctions (GJ) and hemichannels (HC). We examined the effects of meth on Cx expression, function, and its role in NeuroAIDS. We found that meth altered Cx expression and localization, decreased GJ communication between neurons and astrocytes, and induced the opening of Cx43/Cx36 HC. Furthermore, we found that these changes in GJ and HC induced by meth treatment were mediated by activation of dopamine receptors, suggesting that dysregulation of dopamine signaling induced by meth is essential for GJ and HC compromise. Meth‐induced changes in GJ and HC contributed to amplified CNS toxicity by dysregulating glutamate metabolism and increasing the susceptibility of neurons and astrocytes to bystander apoptosis induced by HIV. Together, our results indicate that connexin containing channels, GJ and HC, are essential in the pathogenesis of meth and increase the sensitivity of the CNS to HIV CNS disease.

image

Methamphetamine (meth) is an extremely addictive central nervous system stimulant. Meth reduced gap junctional (GJ) communication by inducing internalization of connexin‐43 (Cx43) in astrocytes and reducing expression of Cx36 in neurons by a mechanism involving activation of dopamine receptors (see cartoon). Meth‐induced changes in Cx containing channels increased extracellular levels of glutamate and resulted in higher sensitivity of neurons and astrocytes to apoptosis in response to HIV infection.
Tardive intermittent massive vaginal bleeding from abnormal blood vessels within cesarean scar: Two more new cases should bring our attention to a new entity
Authors: Liao Xiangling , Zhang Pu , Zhang Caiyi , Lu Gary
Published: March 2016

The two cases in this report had intermittent massive vaginal bleeding with a distant history of cesarean delivery. Such severe bleeding was life‐threating but was eventually cured by surgical management. To the best of our knowledge, this is the second report of cases of tardive vaginal bleeding caused by abnormal blood vessels embedded within cesarean scars. The two new cases in this report suggest a novel cause of tardive vaginal bleeding, which should bring our special attention to post‐cesarean clinical practice.
Beyond the Surface: Where Cultural Contexts and Scientific Analyses Meet in Museum Conservation of West African Power Association Helmet Masks
Authors: O'Hern Robin , Pearlstein Ellen , Gagliardi Susan Elizabeth
Published: March 2016

How should museum conservators balance respect for objects created within secrecy contexts with concern for technical understanding and preservation? As described in this article, West African power association leaders draw on guarded knowledge to construct masks and other objects from a variety of animal, vegetal, and mineral matter. The works feature accumulations of diverse materials but often enter museum collections with scant or inaccurate records of the specific matter used in the objects’ making. Conservators charged with the objects’ care confront contradictions stemming from a professional commitment to identify materials intended to remain unknown and to conserve objects never designed to endure in perpetuity as finished forms. In this study, we identify and respond to North American museum conservators’ and collections staff's desire for culturally informed guidelines for handling West African power association objects. We combine conservation‐based scientific research with art–historical field and archival research to explore possibilities for studying the materially and culturally sensitive objects. We specifically focus on x‐radiography and plant fiber identifications of two West African power association helmet masks presently in a museum collection as a case study for ethical decision making during conservation treatments.
ORA47 (octadecanoid‐responsive AP2/ERF‐domain transcription factor 47) regulates jasmonic acid and abscisic acid biosynthesis and signaling through binding to a novel cis‐element
Authors: Chen Hsing‐Yu , Hsieh En‐Jung , Cheng Mei‐Chun , Chen Chien‐Yu , Hwang Shih‐Ying , Lin Tsan‐Piao
Published: March 2016

ORA47 (octadecanoid‐responsive AP2/ERF‐domain transcription factor 47) of Arabidopsis thaliana is an AP2/ERF domain transcription factor that regulates jasmonate (JA) biosynthesis and is induced by methyl JA treatment. The regulatory mechanism of ORA47 remains unclear. ORA47 is shown to bind to the cis‐element (NC/GT)CGNCCA, which is referred to as the O‐box, in the promoter of ABI2. We proposed that ORA47 acts as a connection between ABA INSENSITIVE1 (ABI1) and ABI2 and mediates an ABI1–ORA47–ABI2 positive feedback loop.

PORA47:ORA47‐GFP transgenic plants were used in a chromatin immunoprecipitation (ChIP) assay to show that ORA47 participates in the biosynthesis and/or signaling pathways of nine phytohormones. Specifically, many abscisic acid (ABA) and JA biosynthesis and signaling genes were direct targets of ORA47 under stress conditions.

The JA content of the P35S:ORA47‐GR lines was highly induced under wounding and moderately induced under water stress relative to that of the wild‐type plants. The wounding treatment moderately increased ABA accumulation in the transgenic lines, whereas the water stress treatment repressed the ABA content.

ORA47 is proposed to play a role in the biosynthesis of JA and ABA and in regulating the biosynthesis and/or signaling of a suite of phytohormone genes when plants are subjected to wounding and water stress.
Cord blood transplantation in a young child with pyruvate kinase deficiency
Authors: Akiyoshi Kensuke , Sekiguchi Kazuhito , Okamoto Tomoko , Suenobu So‐ichi , Izumi Tatsuro
Published: March 2016

Unrelated cord blood transplantation (CBT) was performed for the treatment of pyruvate kinase (PK) deficiency in a female pediatric patient at the age of 1 year 7 months, who had been in severe and frequent transfusion‐dependent hemolytic anemia, despite red blood cell (RBC) PK activity 5.52 IU/gHb. pyruvate kinase‐liver and RBC (PK‐LR) had a compound heterozygous mutation located on exon 8: c.1044G > T/c.1076G > A (K348N/R359H). Hemoglobin and RBC PK corrected to 13.5 g/dL and 9.00 IU/gHb, respectively, with gene correction at 6 months after CBT. CBT should be considered as an option for useful treatment in children with severe PK deficiency in the absence of HLA identical sibling with normal RBC PK activity.
Intrapleural urokinase therapy in a neonate with pleural empyema
Authors: Cha Lily Myung‐Jin , Choi Sunha , Kim Taehwan , Yoon Shin Won
Published: March 2016

Pleural empyema is rare in neonates, and treatment with systemic antibiotics and tube drainage may fail because of the thick viscous fluid, bacterial products with fibrin deposition, and multiple loculations. Intrapleural fibrinolytic therapy with urokinase is an effective and non‐invasive treatment option that avoids surgical intervention, although its use in neonates has not been studied extensively. In this report, we describe the case of a 13‐day‐old male neonate with Escherichia coli sepsis and pneumonia, which rapidly progressed to parapneumonic effusion and pleural empyema. After inadequate response to i.v. antibiotics and chest tube drainage, the patient was successfully treated with intrapleural urokinase.
Novel mutation in SUCLA2 identified on sequencing analysis
Authors: Güngör Olcay , Özkaya Ahmet Kağan , Güngör Gülay , Karaer Kadri , Dilber Cengiz , Aydin Kürşad
Published: March 2016

Succinate‐CoA ligase, ADP‐forming, beta subunit (SUCLA2)‐related mitochondrial DNA depletion syndrome is caused by mutations affecting the ADP‐using isoform of the beta subunit in succinyl‐CoA synthase, which is involved in the Krebs cycle. The SUCLA2 protein is found mostly in heart, skeletal muscle, and brain tissues. SUCLA2 mutations result in a mitochondrial disorder that manifests as deafness, lesions in the basal ganglia, and encephalomyopathy accompanied by dystonia. Such mutations are generally associated with mildly increased plasma methylmalonic acid, increased plasma lactate, elevated plasma carnitine esters, and the presence of methylmalonic acid in urine. In this case report, we describe a new mutation in a patient with a succinyl‐CoA synthase deficiency caused by an SUCLA2 defect.
Vicarious Apologies as Moral Repair
Authors: Cohen Andrew I.
Published: March 2016

Apologies are key components of moral repair. They can identify a wrong, express regret, and accept culpability for some transgression. Apologies can vindicate a victim's value as someone who was due different treatment. This paper explores whether acts with vicarious elements may serve as apologies. I offer a functionalist account of apologies: acts are apologies not so much by having correct ingredients but by serving certain apologetic functions. Those functions can be realized in multiple ways. Whether the offenders are individuals or collectives, they can sometimes fulfill such functions through third party agents. Having vicarious elements does not necessarily undermine the reparative reasons offenders hope to provide.
COMPUTABLE GENERAL EQUILIBRIUM ASSESSMENT OF A COMPOUND DISASTER IN NORTHERN TAIWAN
Authors: Haung Michael C. , Hosoe Nobuhiro
Published: March 2016

Taiwan has high‐tech export‐oriented industries, such as semiconductors and electronic equipment. The capital city area is home to the main industrial complex and has a major fault line running through it. Three out of four nuclear power stations in Taiwan are located close to the capital. Using a single‐country computable general equilibrium model, we simulate a compound disaster consisting of a major earthquake and a power crisis induced by nuclear power shutdown in northern Taiwan to quantify its impact on the Taiwanese economy. Simulation results show that Taiwan's flagship industries, such as semiconductors and electronic equipment, would be severely affected by capital and labor losses in an earthquake but not in a power crisis. This implies that no policy intervention to allocate power to these industries is needed, although we are often tempted to do so in emergencies.
Development of large‐scale seismites in Upper Cretaceous fluvial sandstones in a fault‐proximal setting
Authors: Wizevich Michael C. , Simpson Edward L. , Hilbert‐Wolf Hannah L. , Tindall Sarah E.
Published: March 2016

Large‐scale soft‐sediment deformation structures occur within fluvial sandstone bodies of the Upper Cretaceous Wahweap Formation in the Kaiparowits basin, southern Utah, USA. These structures represent an exceptional example of metre‐scale fault‐proximal, seismogenic load structures in nearly homogenous sandstones. The load structures consist of two types: large‐scale load casts and wedge‐shaped load structures. Large‐scale load casts penetrate up to 4·5 m into the underlying sandstone bed. Wedge‐shaped load structures include metre‐scale, parallel, sub‐vertical features and decimetre‐scale features along the periphery of the large‐scale load casts or other wedge‐shaped load structures. Wedge‐shaped load structures contain well‐developed, medial cataclastic shear deformation bands. All load structures contain pervasive well‐defined millimetre‐thick to centimetre‐thick internal laminae, oriented parallel to the outside form of the load structures and asymptotic to deformation bands. Both types of load structures formed because of an inverted density profile, earthquake‐triggered liquefaction and growth of irregularities (a Rayleigh–Taylor instability) on the sandstone–sandstone erosional contact. The internal laminae and deformation bands formed during deformation and clearly demonstrate polyphase deformation, recording a transition from liquefied to hydroplastic to brittle modes of deformation. Decimetre‐scale wedge‐shaped load structures on the edge of the large‐scale load casts probably formed towards the end of a seismic event after the sediment dewatered and increased the frictional contact of grains enough to impart strength to the sands. Metre‐scale wedge‐shaped load structures were created as the tips of downward foundering sediments were driven into fractures, which widened incrementally with seismic pulsation. With each widening of the fracture, gravity and a suction effect would draw additional sediment into the fracture. Superimposed laminae indicate a secondary syndeformational origin for internal laminae, probably by flow‐generated shearing and vibrofluidization mechanisms. Large‐scale and wedge‐shaped load structures, polyphase deformation and secondary laminae may characterize soft‐sediment deformation in certain fault‐proximal settings.
The Charge from Psychology and Art's Definition
Authors: Monseré Annelies
Published: March 2016

This article argues that the so‐called Charge from Psychology does not refute the project of defining art. The charge entails that the project is misguided because it falsely presupposes that the concept of art is classically structured. The charge is challenged by distinguishing philosophers’ normative from psychologists’ descriptive aims. Unlike what many philosophers of art themselves believe, defining art is a normative project, since proposed definitions formulate conditions under which the concept of art should be applied, rather than is applied. Therefore, it is not inherently problematic that definitions do not fit empirical data: a normative definition need not reflect how people categorize items as art. In the end, this article shows the significance of empirical data for definitions of art.
A single‐center experience with infections due to daptomycin‐nonsusceptible Enterococcus faecium in liver transplant recipients
Authors: Lewis J.D. , Enfield K.B. , Cox H.L. , Mathers A.J. , Sifri C.D.
Published: March 2016

Background

Infections caused by vancomycin‐resistant Enterococcus faecium (VRE) are a major cause of morbidity and mortality in the liver transplant population. Daptomycin (DAP) is often used to treat infections caused by VRE, but DAP nonsusceptibility in Enterococcus is increasing.

Method

Patients with DAP‐nonsusceptible Enterococcus (DNSE) infections who had undergone liver transplantation between January 1, 2010 and July 31, 2014 were retrospectively reviewed. A convenience sample of DNSE isolates was analyzed by pulsed‐field gel electrophoresis (PFGE).

Results

We identified 14 liver transplant recipients (LTRs) who developed DNSE infections post transplantation. Postoperative complications were common, and most patients required repeat abdominal surgery within 90 days of transplantation. The initial DNSE culture was taken a median of 74.5 days post transplant and was secondary to an intra‐abdominal infection in all but 1 patient. Half of patients were VRE colonized before or at the time of organ transplantation, and all those who were not VRE colonized at the time of transplantation later became colonized, a median of 27 days post transplant. Overall mortality in this cohort was 71%. PFGE did not demonstrate genetic relatedness among DNSE isolates.

Conclusion

This study, the largest published series to our knowledge of DNSE infections in LTRs, demonstrates that these infections occur in patients with serious surgical complications and are associated with high morbidity and mortality. Established risk factors for VRE infection were common, as was DAP exposure. Although many risk factors for DNSE infection cannot be changed, this case series identifies several potentially modifiable variables. Further work is needed to identify interventions to decrease the risk of developing DNSE infections in this complex patient population.
The vaginal microbiota, host defence and reproductive physiology
Authors: Smith Steven B , Ravel Jacques
Published: March 2016

The interaction between the human host and the vaginal microbiota is highly dynamic. Major changes in the vaginal physiology and microbiota over a woman's lifetime are largely shaped by transitional periods such as puberty, menopause and pregnancy, while daily fluctuations in microbial composition observed through culture‐independent studies are more likely to be the results of daily life activities and behaviours. The vaginal microbiota of reproductive‐aged women is largely made up of at least five different community state types. Four of these community state types are dominated by lactic‐acid producing Lactobacillus spp. while the fifth is commonly composed of anaerobes and strict anaerobes and is sometimes associated with vaginal symptoms. The production of lactic acid has been associated with contributing to the overall health of the vagina due to its direct and indirect effects on pathogens and host defence. Some species associated with non‐Lactobacillus vaginal microbiota may trigger immune responses as well as degrade the host mucosa, processes that ultimately increase susceptibility to infections and contribute to negative reproductive outcomes such as infertility and preterm birth. Further studies are needed to better understand the functional underpinnings of how the vaginal microbiota affect host physiology but also how host physiology affects the vaginal microbiota. Understanding this fine‐tuned interaction is key to maintaining women's reproductive health.

image
Numerical Simulation of Damage Evolution and Life Prediction for Two Commercial Fe–Cr–Ni Alloys Subjected to Mechanical and Environmental Factors
Authors: Shen Limin , Jin Peibin , Wang Yanfei , Gong Jianming
Published: March 2016

Associated with mechanical and environmental degradation, such as low-oxygen potential, high carbon activity, and high operating temperature, premature failure generally occurs in ethylene cracking furnace tube. This work is aimed at damage evolution numerical simulation and life prediction of two commercial Fe–Cr–Ni alloys (HP40Nb alloy and KHR45A alloy) under different operating temperatures, subjected to coupled carburization damage and creep damage. The results show that carburization is the most important factor that caused ethylene cracking furnace tube to rupture ahead of service time. Increased operating temperatures accelerate the damage rate markedly for the two alloys. For HP40Nb alloy and KHR45A alloy, the service life at 1223 K is almost 2.5 and 3 times higher than the value at 1323 K, respectively. Due to a higher mass of Ni/(Cr + Fe) ratio, the service life of KHR45A alloy is longer than that of HP40Nb alloy at the same operating condition. Distribution of von Mises stress σe and maximum principal stress σp along the inner surface and the outer surface of tubes is different to each other with damage evolution at different operating temperatures.
Quantifying Cartilage Contact Modulus, Tension Modulus, and Permeability With Hertzian Biphasic Creep
Authors: Moore A. C. , DeLucca J. F. , Elliott D. M. , Burris D. L.
Published: March 2016

This paper describes a new method, based on a recent analytical model (Hertzian biphasic theory (HBT)), to simultaneously quantify cartilage contact modulus, tension modulus, and permeability. Standard Hertzian creep measurements were performed on 13 osteochondral samples from three mature bovine stifles. Each creep dataset was fit for material properties using HBT. A subset of the dataset (N = 4) was also fit using Oyen's method and FEBio, an open-source finite element package designed for soft tissue mechanics. The HBT method demonstrated statistically significant sensitivity to differences between cartilage from the tibial plateau and cartilage from the femoral condyle. Based on the four samples used for comparison, no statistically significant differences were detected between properties from the HBT and FEBio methods. While the finite element method is considered the gold standard for analyzing this type of contact, the expertise and time required to setup and solve can be prohibitive, especially for large datasets. The HBT method agreed quantitatively with FEBio but also offers ease of use by nonexperts, rapid solutions, and exceptional fit quality (R2 = 0.999 ± 0.001, N = 13).
Teaching an Undergraduate Introductory Finite Element Analysis Course: Successful Implementation for Students Learning
Authors: Hossain Awlad
Published: March 2016

In our institution, we offer a one-quarter long finite element analysis (FEA) class for Mechanical Engineering curriculum. This course teaches computational methods to solve engineering problems using the state of art FEA software ANSYS. The coursework involves teaching fundamental mathematical theories to build the concept, analyzing simple structural problems using matrix algebra, and then solving a wide variety of engineering problems dealing with statics, dynamics, heat transfer and others. Students enrolled in this class solve varieties of problem by analytical approach, finite element approach using matrix algebra, using APDL (ANSYS Parametric Design Language) and ANSYS Workbench. As we are in quarter system, it is challenging to solve additional multidisciplinary complex engineering problems in regular class lectures. Therefore, students enrolled in this class are required to conduct a project solvable by student version of ANSYS within very short time. The project must have adequate engineering complexity conveying interesting knowledge or technical concepts to the entire class. Students have to prepare a brief written report, and share what they have learned with the entire class giving an oral presentation. While a course in FEA could be a common offering in many universities, the author of this paper presents the pedagogical approaches undertaken to successfully implement the course objectives to the undergraduate engineering students. The topics and techniques applied to teach different concepts of FEA to enhance students learning outcomes are addressed in this paper.
Adaptive Robust Control for Hydraulic Actuators With Disturbance Estimation
Authors: Xu Z. B. , Yao J. Y. , Dong Z. L. , Zheng Y.
Published: March 2016

In this paper, an adaptive robust control for hydraulic actuators with disturbance estimation is proposed for a hydraulic system with mismatched generalized uncertainties (e.g., parameter derivations, external disturbances, and/or unmodeled dynamics), in which a finite time disturbance observer and an adaptive robust controller are synthesized via backstepping method. The finite time disturbance observer is designed to estimate the mismatched generalized uncertainties. The adaptive robust controller is designed to handle parametric uncertainties and stabilize the closed loop system. The proposed controller accounts for not only the parametric uncertainties, but also the mismatched generalized uncertainties. Furthermore, the controller theoretically guarantees a prescribed tracking transient performance and final tracking accuracy while achieving asymptotic tracking performance after a finite time T0, which is very important for high accuracy tracking control of hydraulic servo systems. Simulation results are obtained to verify the high performance nature of the proposed control strategy.
Single Point Incremental Forming of Friction Stir Processed AA6063-O Alloy
Authors: Velukkudi Santhanam Senthil Kumar , Ganesan Vigneshwaran , Shanmuganatan Subramanian Pillappan
Published: March 2016

In the recent manufacturing trend and, in particular, in sheet metal forming, the requirement of customized production is still growing. Incremental forming is a special technique requiring no high capacity presses or set of dies, thus meeting the increasing demand for low volume production and rapid prototyping. The complex three dimensional parts of sheet metals are formed by the computer numerical control (CNC) movement of a simple generative hemispherical tool. In this paper, the single point incremental forming process is performed on friction stir processed AA 6063-O alloy. The process parameters for the experiment are taken based on L9 Orthogonal array. In this paper the maximum wall angle or the formability is investigated on a formed pyramid frusta. It is inferred that Friction stir process has improved the ductility of the aluminium alloy thus contributing to enhanced formability.
Shrinking Graphene Nanopore Using Electron-Beam-Induced Deposition for Single Molecule Detection
Authors: Ma Jian , Zhao Weiwei , Liu Lei , Sha Jingjie , Chen Yunfei
Published: March 2016

Solid-state nanopore has already shown success of single molecule detection and graphene nanopore is potential for successful DNA sequencing. Here, we present a fast and controllable way to fabricate sub-5 nm nanopore on graphene membrane. The process includes two steps: sputtering a large size nanopore using a conventional focused ion beam (FIB) and shrinking the large nanopore to a few nanometers using scanning electron microscope (SEM). We also demonstrated the ability of the graphene nanopores fabricated in this manner to detect individual 48Kbp λ-DNA molecules.
Innovative Nose Cone Design of Aircraft
Authors: Ranjan Robin R. , Parmar Devendra V. , Raipuria Hardik K. , Singh Pradeep B.
Published: March 2016

The term aerodynamic design means to have a drag reducing shape that cause to reduce the resistance offered by the fluid. Currently designs of the aircraft nosecone is simple rigid shaped Our concept is to have a type of inter-flight convertible nosecone, which can change its shape according with the physical condition of the environment, it means when the aircraft is to take-off, at that time it must have the most aerodynamic shape. And thus the shape of its nosecone should be sharp or may be pin pointed. And if the aircraft has to land back on the runway, it has to resist the air so that the landing can be much smoother & safer. Thus the shape of the nosecone must be blunt. To make this possible we have an idea of conversion of the nosecone during the flight, To verify our idea and to found its real application, we have done various aerodynamic nosecone analysis for aircraft, for which we have followed various mathematical series like ogive series, hack series, power series and ellipse series to find out the best possible solution. We are aiming for the better nosecone design of aircraft, whose shape will vary with the situation and thus it is possible to increase the efficiency of the aircraft in terms of aerodynamic.
Optimizing the Compressed Air Consumption of Milling Machines
Authors: Schilberg Daniel , Schüller Florian , Ridder Folko
Published: March 2016

Compressed air is a clean solution for energy transmission, but it is also an expensive way to provide energy. In times of international competition of manufactures, it is important to identify possibilities to decrease manufacturing costs. The contribution at hand focuses on the optimization of providing compressed air. Most compressed air systems provide the working fluid not only in the periods when required, but also 24/7. We set up milling machines as a test system to detect the optimization potentials like leaks, additional valves and the identification of time intervals in which compressed air is actually needed. The test setup is changed after every measuring phase with the result of reducing the compressed air consumption by up to 50%.
Vertically Integrated Projects: Improving the Overall University Competition Experience
Authors: Chipman Gregory D. , Fuller Thomas F.
Published: March 2016

Beginning in 2009, Vertically Integrated Projects (VIP) courses have been implemented at Georgia Tech. These VIP classes allow undergraduate students to receive academic credit for participating on teams that further faculty research efforts. The teams are multidisciplinary, vertically-integrated, and long-term. Participation on these teams has been shown to help students develop an understanding of project timelines, and effective project communication, while gaining other applicable real-world experience.

EcoCAR 3 is the latest in a series of Advanced Vehicle Technology Competitions (AVTCs) sponsored by the Department of Energy since 1988. At Georgia Tech, the EcoCAR 3 team has been structured using the VIP program to improve the all-around experience of faculty members and the graduate and undergraduate students. Based on Georgia Tech’s previous experience in EcoCAR 1, the team leadership hoped to increase participation of undergraduate students, improve collaboration between students and faculty members, and raise retention levels. The team has shown improvements in each of these categories through implementation of the VIP program. Some of the primary challenges that the team experienced during the first year of competition are also presented here, along with plans for further improvement in future years of the competition.
Multi-Objective Optimization of Time-Delayed Fractional-Order Damping for Better Step Response
Authors: Sardahi Yousef , Naranjani Yousef , Chen YangQuan , Sun Jian-Qiao
Published: March 2016

In this paper, a multi-objective optimization of a time-delayed fractional order damping system is presented. In previous studies, a single objective optimization of this system was based on minimizing the integral of the squared error JISE, integral of the time-weighted squared error JITSE, integral absolute error JIAE, or integral time-weighted absolute error JITAE. However, from the practical point of view other design goals such as those related to system’s response and stability should be also included since an error-based optimized system can result in a system having the smallest error but at the expense of other crucial objectives. Moreover, the one-objective optimization returns only one design option hiding many important details about other possible design preferences. Here, the system under study is optimized by considering three objectives: peak time tp, the percentage overshoot Mp(%), and JISE. The results show that the multi-objective optimization technique provides more information about the system behavior and grants the decision maker different design options, called the Pareto set. In addition, this study investigates the meaning of the aforementioned integral errors within the multi-objective optimization scope.
3-D FEM Stress Analysis and Mechanical Characteristics in Bolted Joints Under External Tensile Loadings
Authors: Sawa Shunichiro , Ishimura Mitsutoshi , Sekiguchi Yasuhisa , Sawa Toshiyuki
Published: March 2016

In practical design for bolted joints, the stress concentration factor (SCF) of the first root in screw threads is important. In the present paper, the SCF in screw threads taking account of spiral in the screw threads is analyzed using three-dimensional Finite Element Method (FEM). In addition, the stress states of screw threads under repeated and static loadings are analyzed in elasto-plastic deformation range. The effect of bolt nominal diameter (M12, M24 and M33) on SCF is also examined. In addition, the experiment to measure the strains at the roots of screw threads was carried out newly. It is found that the FEM result is fairly coincided with the measured results. It is also found that the SCF increases as the bolt nominal diameter increases and the maximum stress is found to occur at the half pith from the engaged screw threads. The value of SCF is smaller in the coarse screw threads of M12 than that in the fine screw threads of M 12. Finally, the bolt ruptures for several nominal diameters are shown to occur from screw threads in the non-engagement in bolted joints under static loadings and under the repeated loadings the bolts are ruptured from the first root of screw threads due to fatigue even if the bolt preload is the higher.
FEM Stress Analysis and Design for Bolted Circular Flange Joints Under Tensile Loading
Authors: Sawa Shunichiro , Ishimura Mitsutoshi , Sekiguchi Yasuhisa , Sawa Toshiyuki
Published: March 2016

In designing a bolted joint, it is necessary to know a ratio of increment Ft in axial bolt force to an external tensile loading W, that is, the load factor φ=Ft/W. In our previous paper, the new formulation for obtaining the value of the load factor φ for a bolted joint in which two hollow cylinders and two T-shape flanges were clamped was proposed by introducing the tensile spring constant Kpt for clamped parts. Then, the values of the load factor of bolted joint obtained from our formulation are shown to be in a fairly good agreement with the experimental values. In the present paper, the mechanical characteristics of bolted circular flange joints are analyzed by Finite Element Method (FEM) and axi-symmetrical theory of elasticity such as the load factor, the contact stress distributions at the interfaces and a load when a separation occurs at the interfaces. For verification of the analyses, experiments were carried out to measure the load factor, the maximums stress and a load when a separation occurs. In the analyses, the effect of the bolt pitch circle diameter D on the value of the load factor is examined. The numerical results of the load factor are fairly coincided with the experimental results. As the results, it is found that the load factor decreases as the bolt pitch circle diameter D increases and that the value of the load factor is less than 0.1. It is also found that the load when the interfaces start to separate decreases as the value of D increases. Based on the obtained results, a design method for the bolted circular flange joints under tensile loadings is demonstrated, that is, the method how to determine the bolt nominal diameter, bolt strength grade, the bolt preload for the external tensile loading are described.
Optimization of Forging Process Parameters and Anvil Design for Railway Axle During High-Speed Forging
Authors: Du Shiwen , Li Yongtang , Song Jianjun
Published: March 2016

Forging is an effective method for railway axle in order to ensure the inner quality, good microstructure and properties. Based on the disadvantage of current processing techniques for railway axle forging such as large machining allowance, low dimension accuracy, materials and energy consumption, a new precision high-speed forging forming process is proposed. The whole forging process of axle is divided into three steps, including chamfering, rounding and forming. Forming qualities of railway axle mainly depend on anvil structure and operational parameters during high-speed forging. Simulation model is established using finite element method by DEFORM. Focusing on the forging stage of the railway axles, the influences of anvil design have been numerically analyzed. By analyzing the stress-strain distribution and the forming precision with different anvil structures (flat anvil and arc anvil), a new arc anvil for axle forging is proposed. Arc anvil which we put forward is better than flat anvil both forming quality and properties. As for anvil edge shape design, it is effective to select a Per-form zone to obtain high strain at the center. Structure and main parameters are designed. Effect of anvil relative length, transition radius between Per-form zone and relative length, arc radius of arc anvil on forming quality is analyzed in term of surface defects and inner stress-strain distribution. While the radius of arc is 150mm and the central angle of the arc is 90°, the equivalent strain is greater which will be benefit for inner defects cogging. Transition radius between Per-form zone and relative length is 50mm, concave defects on the surface of forging is the smaller. With the increase of relative length, forging force increases. Taking the productivity and inner strain distribution into account, relative length is 240mm. The independent influence of each chosen major operational parameter, i.e, the rotation angle, the feed and the reduction on internal quality and dimensional precision, has been studied. Suitable operational parameters for ensuring internal quality and dimensional precision have been specified. As a result, the optimum combination of rotational angle and relative feed is clarified. Compared with stress-strain distribution and inner strain distribution under different reduction, 20% is taken to ensure better strain status and efficiency, rotation angle is 90°during chamfering. While the relative feed is 0.6, rotation angle is 45° during rounding, rounding precision will be higher. Ellipticity will be best and variance of radius will be small. Experiment research is performed in 10MN high-speed hydraulic press. Compared with the forming size precision, the experimental results verified the feasibility of the structure of arc anvil and the operational parameters.
Tracheal Stenosis: A CFD Approach for Evaluation of Drug Delivery
Authors: Taherian Shahab , Rahai Hamid , Gomez Bernardo Z. , Waddington Thomas , Bonifacio Jeremy R.
Published: March 2016

The existence of obstructions such as tracheal stenosis has major impacts on respiratory functions. Therapeutic effectiveness of inhaled medications is influenced by tracheal stenosis, and particle transport and deposition pattern are modified. The majority of studies have focused on obstructions in branches of the airways, where the flow is diverted to the other branches to meet the needed oxygen intake. In this study we have investigated the effects of trachea with and without stenosis/obstruction on particle depositions and air flow in a human respiratory system. Patient specific CFD simulations were conducted; CT-scans of a patient with tracheal stenosis were used to create 3D models of bronchial tree up to 8 generations. The section of the stenosis was manually modified to create a healthy trachea. Comparisons between CFD simulations before and after intervention demonstrate the impact of the stenosis on flow characteristics and particles distribution. The numerical investigations were performed using the implicit Unsteady Reynolds-Averaged Navier-Stokes equation (U-RANS), using the commercially available software (STAR-CCM+) from CD-Adapco, along with K-ω; shear stress transport model. Two sets of CT-images of inhalation and exhalation were used for assigning Patient-specific boundary conditions at the outlets. Lagrangian Phase model was used to simulate particle transport and depositions of 10, 5 and 2.5 micron diameter particles. Results of the particle depositions for 10 micron particles highlight the difference in depositions and ultimately inhaled medications in patients with and without tracheal stenosis. Particle deposition for normal Tidal volume increased due to stenosis from 47% to 51% for 10 Micron particles and not a significant change for the 2.5 Micron particles (from 4.5% to 4.7%).

Comparisons of pressure drop in each generation between patient with tracheal stenosis and the healthy lung showed significant increase in pressure drop after the stenosis, which were experienced in all generations downstream. Experimental validation of the CFD results were made with a model of healthy trachea up to 3rd generation, manufactured using Additive Layer Manufacturing (ALM) from CT-images and pressure results were compared with the corresponding CFD results. Good agreements were found.
Electro-Thermal Modelling for Material Removal Study in Electric Discharge Machining Process
Authors: Pachaury Yash , Tandon Puneet
Published: March 2016

In the present study, an attempt has been made to model the electric discharge machining process using the numerical simulation technique. Realistic parameters are added in the model such as variable fraction of heat going to the electrodes, and variation in the plasma flushing efficiency with the process parameters. Gaussian distributed heat flux is applied at the spark location and the two-dimensional heat conduction equation is solved with the help of finite element analysis technique to determine the temperature distribution within the two-dimensional process continuum, using averaged thermo-physical properties of the work material. Melting isotherms are determined and the material removed during a single discharge is obtained from it. Material removal rate is determined using a regression model for the plasma flushing efficiency. Experimental validation is made with the help of highly precise AGIE SIT experimental data. The material removal rate is also compared with state of the art research of other researchers. It has been observed that, at low value of the discharge energies, the proposed model is able to predict the experimental material removal rate better than that of the model proposed by other researchers. However, as the discharge energy increases, the accuracy of prediction decreases. The model can be used for achieving process parameter optimization hence saving both the costs and large lead times associated with determining optimized parameters experimentally.
Airfoil Optimization Using Area-Preserving Free-Form Deformation
Authors: Leloudas Stavros N. , Strofylas Giorgos A. , Nikolos Ioannis K.
Published: March 2016

Given the importance of structural integrity of aerodynamic shapes, the necessity of including a cross-sectional area equality constraint among other geometrical and aerodynamic ones arises during the optimization process of an airfoil. In this work an airfoil optimization scheme is presented, based on Area-Preserving Free-Form Deformation (AP FFD), which serves as an alternative technique for the fulfillment of a cross-sectional area equality constraint. The AP FFD is based on the idea of solving an area correction problem, where a minimum possible offset is applied on all free-to-move control points of the FFD lattice, subject to the area preservation constraint. Due to the linearity of the area constraint in each axis, the extraction of an inexpensive closed-form solution to the area preservation problem is possible by using Lagrange Multipliers. A parallel Differential Evolution (DE) algorithm serves as the optimizer, assisted by two Artificial Neural Networks as surrogates. The use of multiple surrogate models, in conjunction with the inexpensive solution to the area correction problem, render the optimization process time efficient. The application of the proposed methodology for wind turbine airfoil optimization demonstrates its applicability and effectiveness.