bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular cloning, expression of, and regulation by thyroid‐hormone receptor α A in the half‐smooth tongue sole Cynoglossus semilaevis during metamorphosis
Authors: Zhang W. T. , Liu K. , Xiang J. S. , Zhang L. Y. , Liu W. J. , Dong Z. D. , Li Y. Z. , Li H. L. , Chen S. L. , Wang N.
Published: March 2016

To elucidate the effect of thyroid hormone receptor α A (thraa) on metamorphosis, the full length cDNA of half‐smooth tongue sole Cynoglossus semilaevis was cloned. The relative gene transcript level of thraa at different development stages was quantified using real‐time PCR. Transcription of thraa increased and declined rapidly during metamorphosis. Hyperthyroidism was induced in juveniles and larvae with exposure to T3 and T4, and hypothyroidism with thiourea (TU), 2‐mercapto‐1‐methylimidazole (MMI). thraa mRNA was higher in fish treated for 6 days with MMI than in untreated controls, although inhibited larvae did not complete metamorphosis. The addition of exogenous T4 reversed this effect in the MMI‐treated group, but not in the TU‐treated group. In situ hybridization revealed progressive tail end of body growth and change during developmental stages, with corresponding changes in thraa expression. This process may be induced by thyroid hormones with thraa as a major mediator. The morphological changes of tip of the tail may be associated with the development of lateral swimming.
Oligomerization of the microtubule‐associated protein tau is mediated by its N‐terminal sequences: implications for normal and pathological tau action
Authors: Feinstein H. Eric , Benbow Sarah J. , LaPointe Nichole E. , Patel Nirav , Ramachandran Srinivasan , Do Thanh D. , Gaylord Michelle R. , Huskey Noelle E. , Dressler Nicolette , Korff Megan , Quon Brady , Cantrell Kristi Lazar , Bowers Michael T. , Lal Ratnesh , Feinstein Stuart C.
Published: March 2016

Despite extensive structure‐function analyses, the molecular mechanisms of normal and pathological tau action remain poorly understood. How does the C‐terminal microtubule‐binding region regulate microtubule dynamics and bundling? In what biophysical form does tau transfer trans‐synaptically from one neuron to another, promoting neurodegeneration and dementia? Previous biochemical/biophysical work led to the hypothesis that tau can dimerize via electrostatic interactions between two N‐terminal ‘projection domains’ aligned in an anti‐parallel fashion, generating a multivalent complex capable of interacting with multiple tubulin subunits. We sought to test this dimerization model directly. Native gel analyses of full‐length tau and deletion constructs demonstrate that the N‐terminal region leads to multiple bands, consistent with oligomerization. Ferguson analyses of native gels indicate that an N‐terminal fragment (tau45–230) assembles into heptamers/octamers. Ferguson analyses of denaturing gels demonstrates that tau45–230 can dimerize even in sodium dodecyl sulfate. Atomic force microscopy reveals multiple levels of oligomerization by both full‐length tau and tau45–230. Finally, ion mobility–mass spectrometric analyses of tau106–144, a small peptide containing the core of the hypothesized dimerization region, also demonstrate oligomerization. Thus, multiple independent strategies demonstrate that the N‐terminal region of tau can mediate higher order oligomerization, which may have important implications for both normal and pathological tau action.

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The microtubule‐associated protein tau is essential for neuronal development and maintenance, but is also central to Alzheimer's and related dementias. Unfortunately, the molecular mechanisms underlying normal and pathological tau action remain poorly understood. Here, we demonstrate that tau can homo‐oligomerize, providing novel mechanistic models for normal tau action (promoting microtubule growth and bundling, suppressing microtubule shortening) and pathological tau action (poisoning of oligomeric complexes).
Ruminal phytate degradation of maize grain and rapeseed meal in vitro and as affected by phytate content in donor animal diets and inorganic phosphorus in the buffer
Authors: Haese E. , Lengowski M. , Gräter E. , Föll A. , Möhring J. , Steingass H. , Schollenberger M. , Rodehutscord M.
Published: March 2016

The ruminal disappearance of phytate phosphorus (InsP6‐P) from maize grain and rapeseed meal (RSM) was determined in two in vitro studies. In experiment 1, two diets differing in phosphorus (P) and InsP6‐P concentration were fed to the donor animals of rumen fluid (diet HP: 0.49% P in dry matter, diet LP: 0.29% P). Maize grain and RSM were incubated in a rumen fluid/saliva mixture for 3, 6, 12 and 24 h. In experiment 2, a diet similar to diet HP was fed, and the rumen fluid was mixed with artificial saliva containing 120 mg inorganic P/l (Pi) or no inorganic P (P0). Maize grain and RSM were incubated with either buffer for 3, 6, 12 and 24 h. Total P (tP) and InsP6 concentration were analysed in the fermenter fluids and feed residues. The disappearance of InsP6‐P from maize was completed after 12 h of incubation in both experiments. From RSM, 93% (diet LP) and 99% (diet HP) of the InsP6‐P in experiment 1 and 80% (Pi) and 89% (P0) in experiment 2 had disappeared after 24 h of incubation. InsP6‐P disappearance was higher when diet HP was fed (maize: 3 and 6 h; RSM: 6 and 24 h of incubation) and when rumen fluid was mixed with buffer P0 (maize: 6 h; RSM: 12 and 24 h of incubation). InsP6‐P concentration in the fermenter fluids was higher for maize, but no accumulation of InsP6‐P occurred, indicating a prompt degradation of soluble InsP6. These results confirmed the capability of rumen micro‐organisms to efficiently degrade InsP6. However, differences between the feedstuffs and diet composition as well as the presence of inorganic P in the in vitro system influenced the degradation process. Further studies are required to understand how these factors affect InsP6 degradation and their respective relevance in vivo.
Prices In Motion: Towards A Schumpeterian Price Theory
Authors: Bloch Harry
Published: March 2016

To Schumpeter, endogenous development is an essential characteristic of capitalism that disrupts the equilibrium of the circular flow of the economy. Price equilibrium in the circular flow is displaced by an analysis of prices in motion. The diversion of productive inputs from their existing employment through competition from entrepreneurs and the process of creative destruction both impact on prices throughout the economy and generate business cycles. While Schumpeter's theory of the business cycle and, implicitly, his price theory, have been heavily criticized, this article suggests a way forward to a revised theory of prices in motion.
Emergency Response in Complex Buildings: Automated Selection of Safest and Balanced Routes
Authors: Zverovich V. , Mahdjoubi L. , Boguslawski P. , Fadli F. , Barki H.
Published: March 2016

The extreme importance of emergency response in complex buildings during natural and human‐induced disasters has been widely acknowledged. In particular, there is a need for efficient algorithms for finding safest evacuation routes, which would take into account the 3‐D structure of buildings, their relevant semantics, and the nature and shape of hazards. In this article, we propose algorithms for safest routes and balanced routes in buildings, where an extreme event with many epicenters is occurring. In a balanced route, a trade‐off between route length and hazard proximity is made. The algorithms are based on a novel approach that integrates a multiattribute decision‐making technique, Dijkstra's classical algorithm and the introduced hazard proximity numbers, hazard propagation coefficient and proximity index for a route.
Globalizing Māori Museology: Reconceptualizing Engagement, Knowledge, and Virtuality through Mana Taonga
Authors: Schorch Philipp , McCarthy Conal , Hakiwai Arapata
Published: March 2016

This article sets out toglobalize Māori museologythroughmana taonga, a concept that is historically grounded and articulated in contemporary museum practice. Mana taonga can be used to reconceptualize issues of engagement, knowledge, and virtuality by exploring ways in which the mutual, asymmetrical relations underpinning global, scientific entanglements of the past can be transformed into reciprocal, symmetrical forms of cross‐cultural curatorship and anthropology in the present. In doing so, the Cook/Forster Collection held at the Georg‐August‐Universität Göttingen, Germany, is being (re)approached from a Māori perspective. This collection embodies the first material evidence of the remarkable encounter between Pacific and European people in the 1700s and materializes the moment when two worlds of meaning became entangled and mutually constitutive with continuing significance for Pacific people and European understandings. Reconnecting both sides of the encounter through research on the history of the collection, its contemporary legacy, and Māori engagements with Western anthropology and museology allows us to correct lopsided (re)interpretations of indigenous cultures in exhibitionary projects and one‐sided accounts of museums and indigenous people that dominate the literature.
The microbiome–systemic diseases connection
Authors: van der Meulen TA , Harmsen HJM , Bootsma H , Spijkervet FKL , Kroese FGM , Vissink A
Published: March 2016

The human microbiome consists of all microorganisms occupying the skin, mucous membranes and intestinal tract of the human body. The contact of the mucosal immune system with the human microbiome is a balanced interplay between defence mechanisms of the immune system and symbiotic or pathogenic microbial factors, such as microbial antigens and metabolites. In systemic autoimmune diseases (SADs) such as rheumatoid arthritis, systemic lupus erythematosus and Sjögren's syndrome, the immune system is deranged to a chronic inflammatory state and autoantibodies are an important hallmark. Specific bacteria and/or a dysbiosis in the human microbiome can lead to local mucosal inflammation and increased intestinal permeability. Proinflammatory lymphocytes and cytokines can spread to the systemic circulation and increase the risk of inflammation at distant anatomical sites, such as the joints or salivary glands. Increased intestinal permeability increases antigen exposure and the risk of autoantibody production. If the human microbiome indeed plays such a critical role in SADs, this finding holds a great promise for new therapeutic strategies, such as diet interventions and probiotics and prebiotics. This review provides a background on the human microbiome and mucosal immunity in the gut and oral cavity and gives a summary of the current knowledge on the microbiome–SADs connection.
Electromyographic Abnormalities Associated with Symptomatic Sacral Tarlov Cysts
Authors: Hulens Mieke , Bruyninckx Frans , Dankaerts Wim , Vansant Greet , De Mulder Peter A.
Published: March 2016

Tarlov or perineural cysts (TC) are commonly overlooked as a cause of sacral and ischial pain, and urogenital and bowel problems. TC can be seen on MRI, but are often considered asymptomatic. This is especially true for smaller cysts. Moreover, there are only few diagnostic characteristics that can be used to confirm that the cysts are the cause of the symptoms. As a consequence, a lot of controversy remains regarding the clinical importance of TC. Because of this underdiagnosed condition, patients often suffer for several years from unrecognized chronic neuropathic pain and neurological conditions. In this article, case reports of three patients with giant and smaller symptomatic sacral cysts are presented, in which electromyographic testing was performed to demonstrate nerve damage.

We suggest that electromyography of the sacral nerve roots can be a reasonable tool for the diagnosis of symptomatic TC, as well as for the differentiation from other pathological entities causing sacral and ischial pain. Moreover, using electromyography it was also documented that smaller cysts of < 1 cm can cause nerve damage. Therefore incidence of symptomatic TC may be higher than initially thought.
Juvenile gout in methylmalonic acidemia
Authors: Charuvanij Sirirat , Pattaragarn Anirut , Wisuthsarewong Wanee , Vatanavicharn Nithiwat
Published: March 2016

Methylmalonic acidemia (MMA) is an inborn error of metabolism caused by either deficiency of the enzyme methylmalonyl‐CoA mutase or a defect in adenosyl‐cobalamin synthesis. Chronic kidney disease is its common complication and, in combination with persistent acidosis, leads to hyperuricemia. Symptomatic hyperuricemia or gout, however, has not been reported in MMA. We herein report two pediatric cases of MMA caused by MMAB mutations (cblB defect) with renal tubular acidosis, chronic kidney disease, hyperuricemia, and gout. The clinical findings of gout in these cases included recurrent first metatarsophalangeal arthritis and/or tophi. The patients responded to treatment with colchicine and allopurinol.
Chronic active EBV infection with features of granulomatosis with polyangiitis
Authors: Shimomura Masaki , Morishita Hideaki , Meguro Takaaki , Seto Shiro , Kimura Mitsuaki , Hamazaki Minoru , Hashimoto Ayako , Sugiyama Yuka , Kimura Hiroshi
Published: March 2016

Herein, we report the case of a 13‐year‐old boy with multiple recurrent ulcers on his legs. He developed severe sinusitis at 10 years of age and had significant weight loss (6 kg) in the 2 months prior to admission. Histology of tissue biopsied from the ulcer indicated small vessel vasculitis and granulomatous inflammation. Given that these findings met the diagnostic criteria for granulomatosis with polyangiitis (GPA), he was treated with immunosuppressive agents. Further pathology, however, indicated Epstein–Barr virus (EBV)‐encoded RNA (EBER) in most lymphocytes in the same sample. The EBER‐positive lymphocytes were mainly CD4‐positive T cells. The EBV‐DNA load in the peripheral blood was also abnormally increased (1.0 × 104 copies/μg DNA). Thus, the diagnosis was established as chronic active EBV infection (CAEBV). This case illustrates the necessity of careful differential diagnosis of CAEBV owing to its clinical resemblance and pathological overlap with GPA.
Percutaneous closure of pseudoaneurysm in the left ventricle in a young child
Authors: Kim Geena , Ban Gil Ho , Lee Hyoung Doo , Sung Si Chan , Kim Hyungtae , Choi Kwang Ho
Published: March 2016

Pseudoaneurysm in the left ventricular outflow tract is a rare complication occurring after cardiac surgery. We report on the successful percutaneous device closure of a pseudoaneurysm in the left ventricular outflow tract, which developed in a 23‐month‐old girl after resection of a subaortic ridge. The pseudoaneurysm was closed using an Amplatzer Vascular Plug II.
Reductions of Gauss–Codazzi Equations
Authors: Conte Robert , Grundland A. Michel
Published: March 2016

We prove that conformally parameterized surfaces in Euclidean space of curvature c admit a symmetry reduction of their Gauss–Codazzi equations whose general solution is expressed with the sixth Painlevé function. Moreover, it is shown that the two known solutions of this type (Bonnet 1867, Bobenko et al. 1997) can be recovered by such a reduction.
Functional network analysis of genes differentially expressed during xylogenesis insoc1fulwoody Arabidopsis plants
Authors: Davin Nicolas , Edger Patrick P. , Hefer Charles A. , Mizrachi Eshchar , Schuetz Mathias , Smets Erik , Myburg Alexander A. , Douglas Carl J. , Schranz Michael E. , Lens Frederic
Published: March 2016

Many plant genes are known to be involved in the development of cambium and wood, but how the expression and functional interaction of these genes determine the unique biology of wood remains largely unknown. We used thesoc1fulloss of function mutant – the woodiest genotype known in the otherwise herbaceous model plant Arabidopsis – to investigate the expression and interactions of genes involved in secondary growth (wood formation). Detailed anatomical observations of the stem in combination withmRNAsequencing were used to assess transcriptome remodeling during xylogenesis in wild‐type and woodysoc1fulplants. To interpret the transcriptome changes, we constructed functional gene association networks of differentially expressed genes using theSTRINGdatabase. This analysis revealed functionally enriched gene association hubs that are differentially expressed in herbaceous and woody tissues. In particular, we observed the differential expression of genes related to mechanical stress and jasmonate biosynthesis/signaling during wood formation insoc1fulplants that may be an effect of greater tension within woody tissues. Our results suggest that habit shifts from herbaceous to woody life forms observed in many angiosperm lineages could have evolved convergently by genetic changes that modulate the gene expression and interaction network, and thereby redeploy the conserved wood developmental program.
The anaphase‐promoting complex initiates zygote division in Arabidopsis through degradation of cyclin B1
Authors: Guo Lei , Jiang Li , Zhang Ying , Lu Xiu‐Li , Xie Qi , Weijers Dolf , Liu Chun‐Ming
Published: March 2016

As the start of a new life cycle, activation of the first division of the zygote is a critical event in both plants and animals. Because the zygote in plants is difficult to access, our understanding of how this process is achieved remains poor. Here we report genetic and cell biological analyses of the zygote‐arrest 1 (zyg1) mutant in Arabidopsis, which showed zygote‐lethal and over‐accumulation of cyclin B1 D‐box‐GUS in ovules. Map‐based cloning showed that ZYG1 encodes the anaphase‐promoting complex/cyclosome (APC/C) subunit 11 (APC11). Live‐cell imaging studies showed that APC11 is expressed in both egg and sperm cells, in zygotes and during early embryogenesis. Using a GFP‐APC11 fusion construct that fully complements zyg1, we showed that GFP‐APC11 expression persisted throughout the mitotic cell cycle, and localized to cell plates during cytokinesis. Expression of non‐degradable cyclin B1 in the zygote, or mutations of either APC1 or APC4, also led to a zyg1‐like phenotype. Biochemical studies showed that APC11 has self‐ubiquitination activity and is able to ubiquitinate cyclin B1 and promote degradation of cyclin B1. These results together suggest that APC/C‐mediated degradation of cyclin B1 in Arabidopsis is critical for initiating the first division of the zygote.
Distribution of Salmonella Serovars and Antimicrobial Susceptibility from Poultry and Swine Farms in Central Vietnam
Authors: Lettini A. A. , Vo Than T. , Marafin E. , Longo A. , Antonello K. , Zavagnin P. , Barco L. , Mancin M. , Cibin V. , Morini M. , Dang Thi Sao M. , Nguyen Thi T. , Pham Trung H. , Le L. , Nguyen Duc T. , Ricci A.
Published: March 2016

This study was conducted to estimate the prevalence of Salmonella spp. and their antimicrobial susceptibilities on poultry and swine farms, sampled in 2 regions in Central Vietnam. A total of 67 poultry farms and 46 swine farms were sampled in a period of 5 months (from September 2012 to January 2013). Salmonella spp. was prevalent in 46.3% and 71.7% of poultry and swine farms, respectively. Altogether, 99 non‐typhoidal Salmonella were isolated and the most common serovars were Salmonella Weltevreden (19%), followed by Salmonella Typhimurium (12%) and Salmonella 4,[5],12:i:‐ (11%). Overall, 71 of 99 (72%) Salmonella isolates were resistant to at least one of the 14 antimicrobial agents tested. Both in poultry and swine farms, high levels of resistance were observed for ampicillin, chloramphenicol, ciprofloxacin, sulphamethoxazole and tetracycline. The presence of Salmonella isolates from poultry and swine farms which were resistant to different classes of antimicrobials suggests that alternative control measures to antimicrobials should be implemented. Moreover, an effective policy should be promoted to encourage a prudent use of these agents in animal farming in Vietnam.
A robust algorithm for estimating regression and dispersion parameters in non-stationary longitudinally correlated Com–Poisson data
Authors: Mamode Khan Naushad
Published: March 2016

In recent years, Com–Poisson has emerged as one of the most popular discrete models in the analysis of count data owing to its flexibility in handling different types of dispersion. However, in a stationary longitudinal Com–Poisson count data set-up where the covariates are time independent, estimation of regression and dispersion parameters based on a generalized quasi-likelihood (GQL) approach involves some major computational difficulties particularly in the inversion of the joint covariance matrix. On the other hand, in practical real-life longitudinal studies, time-dependent covariates leading to non-stationary responses are more frequently encountered. This implies that further computational problems will now arise when estimating parameters under non-stationary set-ups. This paper overcomes this problem by approximating the inverse of the ill-conditioned covariance matrix in the GQL approach through a multidimensional conjugate gradient method. The performance of this novel version of the GQL approach is then assessed on simulations of AR(1) stationary and AR(1) non-stationary longitudinal Com–Poisson counts and on real-life epileptic seizure counts. However, there is not yet an algorithm to generate non-stationary longitudinal Com–Poisson counts nor a GQL algorithm to estimate the parameters under non-stationary set-ups. Thus, the paper also provides a framework to generate non-stationary AR(1) Com–Poisson counts along with the construction of a GQL equation under non-stationary set-ups.
Starved Hydrodynamic Gas Foil Bearings—Experiment, Micromechanical Phenomenon, and Hypotheses
Authors: Heshmat Hooshang , Walton James F.
Published: March 2016

In this paper, a hypothesis for the operating tribological mechanisms and phenomena occurring in compliant surface gas foil bearings subjected to low ambient pressure conditions, such as occur at high altitude or in soft vacuum, will be presented and discussed. Both theoretical and experimental evidence supporting the proposed hypothesis will be presented to show that, under low ambient pressure conditions (i.e., something akin to starved fluid film lubrication), the shaft is supported by a combination of hydrodynamic and morphological elements. The theoretical treatment of the compressible fluid film in a simple gas bearing is highly nonlinear in-and-of-itself, and especially more so when combined with a compliant surface supported on a frictional-elastic foil foundation. Adding a “molecularly starved gas film” to this highly nonlinear system, one encounters a very interesting and complex system that, heretofore, has not been considered. When operating compliant foil gas bearings in a near or soft vacuum, the term hydrodynamic may be considered oxymoronic in that there is little or no apparent fluid/gas to provide “a full hydrodynamic” action. However, theoretical and experimental evidence of compliant surface foil gas bearings operating at low ambient pressures show that they do continue to work and, in fact, can do so quite well given the appropriate compliancy and other factors, as yet to be discussed. In this paper, the situation will be addressed based upon the experimental evidence that resulted in the essential hypothesis that there are elements at work that go above and beyond purely hydrodynamic phenomenon or so-called solid lubrication. These elements include both tribological and morphological interactions, which are at work at all times and it is the respective ratios of hydrodynamic and morphological elements that characterize operation. Evidence is presented to the effect that, even when hydrodynamic effects dominate, morphological interactions contribute to bearing performance and load-carrying capacity and that, when morphological effects dominate, third body and surface elements impart to the interface many of the characteristics and effects of a hydrodynamic film. Thus, by combining classical Reynolds equation modified for compressible media with the quasi-hydrodynamic/continuum equations and the appropriate rheological and morphological parameters, meaningful solutions for foil bearing operating with extreme low-pressure boundary conditions are possible, and which result in increased load-carrying capacity contrary to classical hydrodynamic theory.
Application of Composite Wraps for Strengthening of Buried Steel Pipelines Crossing Active Faults
Authors: Trifonov Oleg V. , Cherniy Vladimir P.
Published: March 2016

In the paper, the efficiency of strengthening of a buried steel pipeline with a composite wrap subjected to an active faults action is analyzed. A three-dimensional numerical model of the pipeline is developed. The pipeline is considered as an elastoplastic steel shell, while the composite wrap is represented as an orthotropic elastic shell. The model takes into account the elastoplastic behavior of soil, contact interaction between the soil and the pipe, large inelastic strains, distortion of the pipeline cross section, and local buckling formation. A normal-slip fault kinematics with large fault offsets is considered in numerical modeling. The effect of the wrap thickness, length, and position relative to the fault plane is analyzed.
Comparing Methods for Establishing Multiscale Material Properties of 0.2 mm Thick Annealed ASTM 304
Authors: Emblom William J. , Ibne Islam Md. F. S. , Jones Richard J. , Aithal Mitra , Wagner Scott , Pesacreta Thomas , Glass Gary A.
Published: March 2016

Producing fuel cells bipolar plates and other devices such as microscale heat exchangers for electronics requires both macroscale and microscale forming processes. At the macroscale, typically, mechanical properties of sheet metal are determined by performing tensile tests. In addition, it has long been recognized that bi-axial tension tests, dome tests, and hydroforming or viscous bulge tests provide the basis for improved understanding of the mechanics of sheet metal forming. At the microscale strain gauges are too large for measuring strains in small regions and membrane theory is only valid at the poles of the bulge. Continuum mechanics models are useful but require tedious thickness measurements for multiple work pieces, requiring extensive sample preparation and analysis.

In this paper experimental results from hydroforming tests for 0.2-mm thick annealed ASTM 304 stainless steel sheet in 11 mm, 5 mm, and 1 mm diameter open dies at various pressures were evaluated. The height of the bulge at the pole and strains based upon measurements of 127 micron strain grids were determined. These dies represent the transition from a small macroscale process to a microscale forming process. Two methods were used to estimate material properties: an analytical model and an iterative method which compared experimental strain results with the strains from a finite element model where the Holloman constitutive properties of the sheet were varied. The problems estimating material properties based upon grid strain measurement, membrane theory, and the iterative finite element approaches were investigated and the results were compared. This study indicates that membrane theory will provide adequate predictions for Holloman constructive properties provided the assumptions for membrane theory are not violated. However, using measured microscale grid deformation strains does not produce very good agreement estimates of the Holloman constitutive model when comparing experimental results with FEA strains. It is believed that while the grid strain measurement method used results in strain measurement errors of less than 1.5% of strain, this error is sufficient to result in enough uncertainty to produce results that are inconsistent with other methods.
Bifurcation Trees of Period-1 Motions to Chaos in a Quadratic Nonlinear Oscillator With Time-Delayed Displacement
Authors: Luo Albert C. J. , Xing Siyuan
Published: March 2016

In this paper, periodic motions in a periodically forced, damped, quadratic nonlinear oscillator with time-delayed displacement are analytically predicted through implicit discrete mappings. The implicit discrete maps are obtained from discretization of differential equation of such a quadratic nonlinear oscillator. From mapping structures, bifurcation trees of periodic motions are achieved analytically, and the corresponding stability and bifurcation analysis are completed through eigenvalue analysis. From the analytical prediction, numerical results of periodic motions are illustrated to verify such an analytical prediction.
Design and Construction of a New Version of the Epi.q UGV for Monitoring and Surveillance Tasks
Authors: Quaglia Giuseppe , Nisi Matteo
Published: March 2016

The paper presents a new member of Epi.q robot family, a series of mobile robots with a wheel-legged locomotion and with the ability to overcome obstacles and move on uneven terrains. The particular feature of this robot family is the ability to switch from a wheel locomotion to a leg locomotion without any external active control but only depending on the dynamic conditions. In particular this work deals with the design of the latest prototype developed, analyzing the design and construction phases. This prototype is more powerful than the previous thanks to the possibility to have four driving units instead of two. The robot architecture has been studied in order to be modular. Several robot configurations can be obtained with the same structure and this allows to test how each component affect the overall robot behavior. Moreover the mechanical design is more accurate and reliable respect to previous versions. A sensing system has been introduced with the aim to evaluate the performances of each robot architecture. Finally an on-board processor has been added. This allows the definition of more complex control logics such as the cooperation between a speed control with a torque control in the four driving units configuration. Moreover it increases the smart tasks that the robot is able to perform such as the developing of a remote autonomous control rather than a manual drive by an operator.
Strains in Aluminum Stamp Formed Pans Resulting From Closed-Loop Control of Local Forces
Authors: Emblom William J.
Published: March 2016

A stamp forming die, whose flexible blank holder was designed using FEA, was built. A closed-loop control system was used to control local punch forces and wrinkling by controlling both blank holder forces and draw bead penetration. The controllers for the draw beads featured an advanced PID controller with a Smith Predictor and Kalman Filter. A Bang-bang controller was also incorporated into the control system in order prevent control saturation. Fuzzy logic was used to transition from once controller to the other. Once closed-loop was implemented, tests were performed to evaluate the strains in the pans for various forming conditions. These results were compared to open-loop tests and it was found that the strains measured from closed-loop control tests resulted in more uniform strains and that the strains were further from the forming limit curves than strains from tests that were performed under open-loop conditions. Furthermore, it was seen that the strains in the regions were local force were controlled resulted in more uniform strain fields. Hence it was concluded that controlling local punch forces resulted in the strain control of critical regions.
Modeling Laser Travel and its Effects on Thermal Stresses in Laser Hardening of Steel
Authors: Ghosh Suhash , Sahay Chittaranjan , Shetty Devdas
Published: March 2016

To achieve a precise and controlled laser process, a thorough analysis of the thermal behavior of the material is necessary. The knowledge of the thermal cycles is important to ascertain suitable processing parameters, thus improving surface properties when the alloys are laser irradiated. In the present paper, a numerical simulation of the laser hardening process has been developed using the finite element (FE) code ABAQUS™ to solve the heat transfer equation inside the treated material (AISI 4140 steel). The thermal analysis is based on Jaeger’s classical moving heat source method by considering the laser beam as a moving plane (band/disc) heat source and the target material is a semi-infinite solid. However, the FE model, used to solve the governing equation, does not directly accommodate the moving nature of heat source. A reasonable approximation is to divide the laser travel on the substrate into many small time/load steps, and apply variable flux and boundary conditions in each time/load step. This approximates the quasi-steady state phenomena over the series of these time steps for the complete laser travel. This paper investigates the effects of the choice of time/load steps on the temperature and thermal stress evolution as well the computing times in the process.
Energy Efficiency Analysis of Interconnected Pneumatic Cylinders Servo Positioning System
Authors: Bangaru Mohan , Devaraj Saravanakumar
Published: March 2016

Pneumatic systems exhibits many advantages including high speed and better efficiency. Servo pneumatic system enables the pneumatic system to be employed in varying position applications such as robots. There will be always a compromise between the speed and allowable overshoot in determining the parameters of the system based on the applications. In present research, a system comprising of two pneumatic cylinders attached to each other is used. A small cylinder which is used to for fine adjustments in accuracy is mounted on the rod end of the large cylinder which travels the coarse movement. This system reduces the overshoot of the system without much reduction in speed. Mathematical model of the system comprising of motion dynamics, pressure and temperature dynamics inside cylinder chambers and mass flow variation in the valves are derived from the physical laws and recent literature information. Based on the mathematical model, a simulation model of the system is created in the Matlab-Simulink software. A fuzzy based control system has been designed for servo position control of the system. The simulation model is validated using the experimental results. The energy efficiency of the system is computed from the overall power developed in the system and cumulative air power supplied to the system. The analysis of the dynamics of the system while tracking a sinusoidal signal is taken as a task for analyzing the energy efficiency of the system. The energy efficiency of the system has been analyzed for various sizes of cylinders, various supply pressure levels to both the cylinders in the system and various applied loads to the system. To reduce the number of experiments to be conducted, a Taguchi based design of experiments is carried out. A statistical analysis has been made for analyzing the variation of energy efficiency with the above parameters. From the study, external load affects the energy efficiency in a considerable way which has 54.39% of the overall contribution. The second dominant factor on influencing energy efficiency is supply pressure to cylinder A which has the contribution of 23.65%.
The Influence of Kinematic Redundancies in the Energy Efficiency of Planar Parallel Manipulators
Authors: Ruiz Andrés G. , Fontes João V. C. , da Silva Maíra M.
Published: March 2016

Parallel manipulators present advantages compared to serial ones, such as higher load-carrying capacity, improved accuracy and increased stiffness. However, parallel manipulators possess limitations due to the presence of singularities. It has been proved that kinematic and actuation redundancy promote a significant reduction in the singularities and homogenization on the actuation forces. This paper evaluates the effect of the addition of kinematic redundancy in the energy efficiency of parallel manipulators. In order to do so, the required mechanical energy consumed by a 3RRR non-redundant planar parallel manipulator and their kinematically redundant versions, to perform several predefined trajectories is minimized using a genetic algorithm. The result of the comparison shows that the required mechanical energy to perform a given trajectory can be reduced with the addition of kinematic redundancy.
How to Take Into Account Model Inaccuracy When Estimating the Uncertainty of the Result of Data Processing
Authors: Kreinovich Vladik , Kosheleva Olga , Pownuk Andrzej , Romero Rodrigo
Published: March 2016

In engineering design, it is important to guarantee that the values of certain quantities such as stress level, noise level, vibration level, etc., stay below a certain threshold in all possible situations, i.e., for all possible combinations of the corresponding internal and external parameters. Usually, the number of possible combinations is so large that it is not possible to physically test the system for all these combinations. Instead, we form a computer model of the system, and test this model. In this testing, we need to take into account that the computer models are usually approximate. In this paper, we show that the existing techniques for taking model uncertainty into account overestimate the uncertainty of the results. We also show how we can get more accurate estimates.
Avoiding of Self-Loosening in Components With Multiple Screw Joints
Authors: Guggolz D. , Manoharan S. K. , Friedrich C.
Published: March 2016

Self-loosening of fastened systems is known as a severe damage mechanism besides the loss of preload due to relaxation and as a result of this the failure of the joint. Main problem is, that self-loosening mostly leads to a rapid preload loss when occurs.

In the 1970s first systematic investigations due to this are reported from Junker et al. using a transverse-vibrational test stand [13]. Nowadays numeric calculation approaches are available (e.g. [12]). All approaches show that very small displacements from loading before complete sliding are sufficient to induce self-loosening — which is a screw rotation against its tightening direction without material rupture of the screw.

Today the mechanism of self-loosening under uni-axial transverse load of single-screwed joints with plain bearing surface is understood and predictable. Also combined loads of vibration and rotation became the focus of university-based research. The challenge is to transfer the knowledge about the mechanism to component fastened systems with multi-screw joints. The fundamental mechanism is not sufficient for component design. This is the reason why up to now no prediction in advance is established in guidelines.

First, this paper shows the time-sequence of self-loosening in general with its different stages. The second step is to work out important influences on self-loosening which will be shown by existing calculations. Then a stress-based calculation and a better criterion for self-loosening will be developed.

Next step, if analytics come to their limits, is the numeric simulation of system behavior. With this the critical preload for self-loosening must be determined to ensure safety of the connection. Following from this screw joints can be dimensioned without risk of self-loosening. The simulation procedure includes right modelling with boundary conditions as well as defining evaluation procedure for a ‘self-loosening-safety-margin’. With simulation of a single-screw joint it gets clear that either analytical or numerical approach can be used. But already for two screws in a fastened system the limits of known equations become obvious.

Finally, results of a vibrational test are shown before conclusions and outlook.
Characterization of Resin-Injection Repair of Impact Damage in Polymer Matrix Composite
Authors: Moghe Ritwik Prashant , Prakash Raghu V. , Sudevan Deepika , Katta Shambhayya Hema
Published: March 2016

Resin injection repair of impact damage in polymer matrix composites is studied using an in-house developed repair methodology. Carbon fiber reinforced polymeric composite specimens were impacted for three levels of impact damage (23 J, 35 J and 51 J — typical of low energy, medium energy, high energy) using a drop tup test rig and the damage zone was characterized using ultrasonic C-scan technique. The impact damaged specimens were repaired using a resin infiltration method. The selection of low viscosity room temperature curing resin, and process parameters such as resin injection pressure and vacuum levels to be maintained were studied to arrive at optimum repair method. The tension, compression strength of laminates prior to impact and post-impact as well as post-repair was studied to assess the quality of repair method. The results indicate that the chosen resin injection repair is effective for the repair of low energy impact damage but not in the case of medium and high energy impact damage.
On the Vibrations of an Axially Moving String With a Time-Dependent Velocity
Authors: Malookani Rajab A. , van Horssen Wim T.
Published: March 2016

The transverse vibrations of an axially moving string with a time-varying speed is studied in this paper. The governing equations of motion describing an axially moving string is analyzed using two different techniques. At first, the initial-boundary value problem is discretized using the Fourier sine series, and then the two timescales perturbation method is employed in search of infinite mode approximate solutions. Secondly, a new approach based on the two timescales perturbation method and the method of characteristics is used. It is found that there are infinitely many values of the velocity fluctuation frequency yielding infinitely many resonance conditions in the system. The response of the system with harmonically varying velocity function is computed for particular harmonic initial conditions.
A Predictive Model for Determining the Location of Chatter Onset in Turning a Slender Workpiece
Authors: Lu Kaibo , Wang Yiliang , Liu Hunju , Lian Zisheng , Yang Zhaojian
Published: March 2016

Chatter is often encountered in machining processes, which reduces the geometric accuracies and dynamic stability of the cutting system. This study was motivated by the fact that chatter arising is generally related to the cutting position during straight turning of slender workpieces, which has seldom been investigated systematically in literature. In this paper, we present a predictive chatter model of turning a tailstock supported slender workpiece including the effect of the cutting tool movement along the longitudinal axis of the workpiece during cutting. Based on linear stability analysis and stiffness distribution at different cutting positions along the workpiece, an entire stability chart for a single cutting pass is constructed. By using this stability chart the critical cutting condition and the chatter onset location can be determined, and the inference of chatter lasting effect that when chatter occurs at some cutting location it will continue for a period of time until another specified location is reached, can also be drawn. Experimental trials were conducted to test the chatter model. The experimental observation was in good agreement with the theoretical inference. The difference between the predicted tool locations and the experimental results was within 9 percent at high speed cutting.
NDT Applied to the Detection of Defects in Oil and Gas Pipes: A Simulation-Based Study
Authors: Alobaidi Wissam M. , Al-Rizzo Hussain M. , Sandgren Eric
Published: March 2016

This research investigates the application of microwave nondestructive testing (NDT) to oil and gas pipe wall reductions (PWR) in manufacturing that are less than full-circumferential in extent. Pipes were modeled using Computer Simulation Technology (CST) simulation software, CST Microwave Studio holding pipe length, wall thickness, depth of PWR and configuration constant. The study looks at 32 models in order to determine sweeping frequency limitations for full-circumferential, half-circumferential, three-quarter-circumferential and quarter-circumferential extents of PWR with 8 widths ranging from 6.35mm to 50.8mm. The limitations were determined to be between the extremes. The 6.35mm width did not cause a resonance peak even with a full-circumferential PWR. The 50.8mm width produced a detectible resonance peak, but it is within the range established by the six middle widths.
Problem Solving in Design of Machine Elements in Mechanical Engineering
Authors: Bzymek Zbigniew M. , Hinkle Steven S. , Jurado Quiroga Zoila E.
Published: March 2016

The Design of Machine Elements course is one of the most difficult and complicated courses in the Mechanical Engineering program. It requires inventive concept generation, the knowledge of geometrical design, and basic knowledge of stress and deformation analyses. On those three elements, the machine elements design philosophy is established and further developed. The course material has to be chosen carefully since the time constrains will allow to cover design of only few essential machine elements. The material is covered by lectures, textbook readings, homework problems, and design projects. In addition to the textbook content the course contains five special elements: Idea Generation, Safety Considerations, Design of the Day (DoD), a Designer’s Liability study, and three projects including Final Project – Shaft Design. In the Idea Generation project, students generate an idea of machine or mechanical device. The Safety Consideration project is done by inspection and documentation of unsafe elements on campus. The Shaft Design Project had students design a shaft system under given constrains. In DoD students present existing advanced machines chosen using different sources or their own industrial internship experience. The Liability assignment addresses the designer’s legal responsibility in case of a defective product that caused an injury or accident. The material taught in the course is larger than conventional machine element design course. The elements added that are beyond the structural analysis bring better understanding of engineering problems during the Senior Design course and later during engineering practice. They allow the students to connect the theory with the real world of engineering challenges. This gives students more satisfaction during the learning process and cognitive benefits during engineering practice. The unconventional inventive design approach of the teaching team (course instructor and GTA) to problem solving is based on many years of instructor’s experience in teaching of engineering problem solving and design. The learning pattern in which students work in teams, both in problem solving and in design exercises, also helps to conduct the course. Thanks to all these elements the learning experience of the course is unique and engaging despite the high level of difficulty associated with it.
Design of MEMS Based Piezo-Resistive Sensor for Measuring Pressure in Endo-Tracheal Tube
Authors: Singru Pravin , Mistry Bhargav , Shetty Rachna , Deopujari Satish
Published: March 2016

Mechanical ventilation is the process of providing artificial breathing support to a patient. More than half of critically ill patients require mechanical ventilation[1]. Though mechanical ventilation increases time for recuperation, it is known to have given rise to complications arising from over-distention of lungs leading to ventilator associated lung injury (VALI) and ventilator induced lung injury (VILI). This paper aims to develop a sensor to identify breathing efforts initiated by the patient and give back responses to the ventilator to regulate ventilation modes and tidal volumes delivered by the ventilator. This will significantly aid in reducing asynchrony between the patient efforts and the ventilator input, thus preventing lung injury. Towards this end, we have simulated and studied the effect of different kinds of dynamic loading and diaphragm membrane thickness of the sensor on its sensitivity on a basic design.
Inverse Dynamic Analysis of Shoulder Muscle Activity During Archery Draw Back
Authors: Reddy Aviktha , Al-Smadi Yahia M.
Published: March 2016

The objective of this study is to conduct biomechanical simulation for a musculoskeletal of archery performance. The simulation aims to find the movement patterns in working postures, the muscle activity and joint reaction forces. The results obtained are discussed and the work presented can help analyze the utilization of various muscles during the performance of the repetitive motion of archery.