bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Detection of Stress Singularities in Finite Element Analysis
Authors: Sinclair G. B. , Beisheim J. R. , Kardak A. A.
Published: October 2018

Finite element analysis (FEA) has become the method of choice for the stress analysis of many of the complex configurations encountered in practice. Such configurations can contain stress singularities. Then, it is critical for the necessarily finite estimates from finite elements to be rejected as valid results for the infinite stresses present. There is an extensive literature devoted to the asymptotic identification of stress singularities that can often, but not always, provide a means for such rejection. The present study seeks to offer a further means of rejection: mesh refinement with divergence checks. These divergence checks are a natural counterpart to the convergence checks of ASME. The two are used together on 265 finite element stresses at 32 different singularities: all of these finite element stresses are thus rejected.
The
2010 Oil Spill in the Gulf of Mexico: Flow-Rate Estimation Based on Satellite-Images Analysis1
Authors: Giraldo Diego
Garcia , Yeung Ronald W.
Published: October 2018

The Deepwater Horizon Mobile Offshore Drilling Unit (MODU) was one of several classes of floatable drilling systems. The explosion on April 20, 2010 led to fatalities and the worst oil spill in the U.S. We present an independent estimate of the oil-flow rate into The Gulf caused by the drill-pipe rupture. We employed the NASA Moderate-Resolution Imaging-Spectroradiometer (MODIS) satellite photographs, starting from the days immediately following the disaster, to determine the magnitude of spill. From these images, we obtained the surface area of the spill and calculated the oil flow rate by two different methods based on contrasting luminance within that area. The first assumes a constant thickness for the total area with upper and lower bounds for the thickness. The second separates the area into different patches based on the luminance levels of each. The probability density function (PDF) of such luminance plots showed natural groupings, allowing patches be identifiable. Each patch maps to a specific thickness. This second approach provides a more accurate average thickness. With the assumption that evaporation and other loss amounted to ∼40% of the spill, we obtained, from the first method, a flow rate ranging from 9,300 barrels per day (BPD) to 93,000 BPD. A value of 51,200 BPD was obtained using patch-separation method. This latter estimate was a plausible value, obtained from the current analysis, but with no details presented in an Extended Abstract in OMAE2012, is remarkably consistent with the “official U.S.-Govt. estimates.”
Evaluation of Performance of Various Coolant Grades When Turning Ti-6Al-4V Alloy With Uncoated Carbide Tools Under High-Pressure Coolant Supplies
Authors: Ezugwu Emmanuel O. , B. da Silva Rosemar , Bonney John , Costa Eder S. , Sales Wisley F. , Machado Alisson R.
Published: October 2018

This work presents the evaluation of three commercially available coolant grades (dicyclohexylamine-based coolant, a triethanolamine-based coolant, and an ester-based coolant) when machining Ti-6Al-4V alloy with high-pressure coolant delivery. The evaluations were based on tool life, tool failure modes, surface integrity, and chip formation. The dicyclohexylamine-based coolant was the more effective coolant when machining at the highest pressure of 20.3 MPa due to its stability at elevated temperature, whereas the triethanolamine-based coolant performed effectively at a pressure of 11 MPa due to its low surface tension properties. Deterioration of the ester-based coolant was found in almost all coolant pressures due to its low resistance to oxidation. Surfaces generated when machining with all coolants grades were generally acceptable with negligible physical damage.
The Prototype for X Framework: Assessing Impact on Self-Reported Prototyping Behavior of Student Designers
Authors: Menold Jessica , Jablokow Kathryn , Simpson Timothy
Published: October 2018

A significant gap exists between engineering students' perceptions of prototypes and prototyping abilities and professionals' perceptions and abilities. Structured prototyping frameworks have recently been developed and proposed as a means to help students close this gap, but the effects of these frameworks on students' behavior have not been assessed. The purpose of this work is to investigate if and how a structured prototyping framework affects the self-reported prototyping behaviors of engineering students. Understanding how structured prototyping frameworks affect students can provide educators with a deeper understanding of the way their students adopt and understand design methods. A mixed method study is presented. A 15-item survey and two open-ended questions were distributed to 235 students in a junior-level mechanical engineering design class in order to capture self-reported prototyping behavior. Quantitative results indicate that significant differences in engineering students' prototyping behaviors exist across time and between groups. Results from qualitative analysis indicate that students in the control group focused solely on improving technical quality, while students in both experimental groups focused on a wider range of design qualities. This study is the first to demonstrate that a structured prototyping framework can affect engineering students' self-reported prototyping behaviors during design activities.
Experimental Investigations on Carryover in a Gravity Separation-Based Steam Drum
Authors: Bagul R. K. , Pilkhwal D. S. , Vijayan P. K. , Joshi J. B.
Published: October 2018

Advanced heavy water reactor (AHWR) is a natural circulation-based, light water-cooled, heavy water-moderated pressure tube type of nuclear reactor. In AHWR, the steam separation takes place in horizontal steam drums purely based on gravity separation principle. It is a known fact that efficiency of gravity separation is affected by the carryover phenomenon, i.e., conveyance of water droplets by the steam. To minimize the carryover, it is advised to reduce the superficial velocities of phases. Lowering the flow velocities also results in to lower pressure drop, which is very much desired. However, careful attention must be given to carryover phenomenon during design. An experimental test facility known as air–water loop (AWL) simulating the scaled down steam drum of AHWR with air–water mixture has been designed and experimental work performed on carryover phenomenon is presented here. Comparison of measured entrainment fraction with existing correlations and other visual observations are described. Numerical simulations with Euler–Lagrangian method have been carried out for which droplet size distribution measured experimentally is used as an input.
Magnetohydrodynamic Boundary Layer Flow and Heat Transfer of Nanofluids Past a Bidirectional Exponential Permeable Stretching/Shrinking Sheet With Viscous Dissipation Effect
Authors: Jusoh Rahimah , Nazar Roslinda , Pop Ioan
Published: October 2018

The problem of boundary layer flow and heat transfer of magnetohydrodynamic (MHD) nanofluids which consist of Fe3O4, Cu, Al2O3, and TiO2 nanoparticles and water as the base fluid past a bidirectional exponentially permeable stretching/shrinking sheet is studied numerically. The mathematical model of the nanofluid incorporates the effect of viscous dissipation in the energy equation. By employing a suitable similarity transformation, the conservative equations for mass, momentum, and energy are transformed into the ordinary differential equations. These equations are then numerically solved with the utilization of bvp4c function in matlab. The effects of the suction parameter, magnetic parameter, nanoparticle volume fraction parameter, Eckert number, Prandtl number, and temperature exponent parameter to the reduced skin friction coefficient as well as the local Nusselt number are graphically presented. Cu is found to be prominently good in the thermal conductivity. Nevertheless, higher concentration of nanoparticles leads to the deterioration of heat transfer rate. The present result negates the previous literature on thermal conductivity enhancement with the implementation of nanofluid. Stability analysis is conducted since dual solutions exist in this study, and conclusively, the first solution is found to be stable.
Homogeneous–Heterogeneous Reactions of Blasius Flow in a Nanofluid
Authors: Xu Hang
Published: October 2018

An investigation is made to study the Blasius flow of a nanofluid in the presence of homogeneous–heterogeneous chemical reactions. Here, the diffusion coefficients of the reactant and autocatalyst are considered to be in comparable sizes. The Buongiorno's mathematical model is applied in describing the behavior of nanofluids. Multiple solutions of the steady-state system of nonlinear ordinary differential equations are obtained. Results show that nanofluids significantly participate in the transport mechanism of the homogeneous–heterogeneous reactions, which play different roles in the procedures of homogeneous and heterogeneous reactions.
The Performance Impact of Integrating Water Storage Into a Chiller-Less Data Center Design
Authors: Rose Isaac , Wemhoff Aaron P. , Fleischer Amy S.
Published: October 2018

Data centers consume an extraordinary amount of electricity, and the rate of consumption is increasing at a rapid pace. Thus, energy efficiency in data center design is of substantial interest since it can have a significant impact on operating costs. The server cooling infrastructure is one area which is ripe for design innovation. Various designs have been considered for air-cooled data centers, and there is growing interest in liquid-cooled server designs. One potential liquid-cooled solution, which reduces the cost of cooling to less than 5% of the information technology (IT) energy use, is a chiller-less or warm water-cooled system, which removes the chiller from the design and lets the cooling water supply vary with changes in the outdoor ambient conditions. While this design has been proven to work effectively in some locations, environmental extremes prevent its more widespread implementation. In this paper, the design and analysis of a cold water storage system are shown to extend the applicability of chiller-less designs to a wider variety of environmental conditions. This can lead to both energy and economic savings for a wide variety of data center installations. A numerical model of a water storage system is developed, validated, and used to analyze the impact of a water storage tank system in a chiller-less data center design featuring outdoor wet cooling. The results show that during times of high wet bulb operating conditions, a water storage tank can be an effective method to significantly reduce chip operating temperatures for warm water-cooled systems by reducing operating temperatures 5–7 °C during the hottest part of the day. The overall system performance was evaluated using both an exergy analysis and a modified power usage effectiveness (PUE) metric defined for the water storage system. This unique situation also necessitates the development of a new exergy definition in order to properly capture the physics of the situation. The impacts of tank size, tank aspect ratio, fill percentage, and charging/discharging time on both the chip temperature and modified PUE are evaluated. It is determined that tank charging time must be carefully matched to environmental conditions in order to optimize impact. Interestingly, the water being stored is initially above ambient, but the overall system performance improves with lower water temperatures. Therefore, heat losses to ambient are found to beneficial to the overall system performance. The results of this analysis demonstrate that in application, data center operators will see a clear performance benefit if water storage systems are used in conjunction with warm water cooling. This application can be extended to data center failure scenarios and could also lead to downsizing of equipment and a clear economic benefit.
Nutrient Signaling via the TORC1-Greatwall-PP2A
B55δ
Pathway Is Responsible for the High Initial Rates of Alcoholic Fermentation in Sake Yeast Strains of Saccharomyces cerevisiae
Authors: Watanabe Daisuke , Kajihara Takuma , Sugimoto Yukiko , Takagi Kenichi , Mizuno Megumi , Zhou Yan , Chen Jiawen , Takeda Kojiro , Tatebe Hisashi , Shiozaki Kazuhiro , Nakazawa Nobushige , Izawa Shingo , Akao Takeshi , Shimoi Hitoshi , Maeda Tatsuya , Takagi Hiroshi
Published: October 2018

The biochemical processes and enzymes responsible for glycolysis and alcoholic fermentation by the yeast
S. cerevisiae
have long been the subject of scientific research. Nevertheless, the factors determining fermentation performance
in vivo
are not fully understood. As a result, the industrial breeding of yeast strains has required empirical characterization of fermentation by screening numerous mutants through laborious fermentation tests. To establish a rational and efficient breeding strategy, key regulators of alcoholic fermentation need to be identified. In the present study, we focused on how sake yeast strains of
S. cerevisiae
have acquired high alcoholic fermentation performance. Our findings provide a rational molecular basis to design yeast strains with optimal fermentation performance for production of alcoholic beverages and bioethanol. In addition, as the evolutionarily conserved TORC1-Greatwall-PP2A
B55δ
pathway plays a major role in the glycolytic control, our work may contribute to research on carbohydrate metabolism in higher eukaryotes.
Biochemical Reconstruction of a Metabolic Pathway from a Marine Bacterium Reveals Its Mechanism of Pectin Depolymerization
Authors: Hobbs Joanne K. , Hettle Andrew G. , Vickers Chelsea , Boraston Alisdair B.
Published: October 2018

Marine polysaccharides, found in the cell walls of seaweeds and other marine macrophytes, represent a vast sink of photosynthetically fixed carbon. As such, their breakdown by marine microbes contributes significantly to global carbon cycling. Pectin is an abundant polysaccharide found in the cell walls of terrestrial plants, but it has recently been reported that some marine bacteria possess the genetic capacity to degrade it. In this study, we biochemically characterized seven key enzymes from a marine bacterium that, together, fully degrade the backbone of pectin into its constituent monosaccharides. Our findings highlight the importance of pectin as a marine carbon source available to bacteria that possess this pathway. The characterized enzymes also have the potential to be utilized in the production of biofuels from plant waste.
Plasticity of Amino Acid Residue 145 Near the Receptor Binding Site of H3 Swine Influenza A Viruses and Its Impact on Receptor Binding and Antibody Recognition
Authors: Santos Jefferson J. S. , Abente Eugenio J. , Obadan Adebimpe O. , Thompson Andrew J. , Ferreri Lucas , Geiger Ginger , Gonzalez-Reiche Ana S. , Lewis Nicola S. , Burke David F. , Rajão Daniela S. , Paulson James C. , Vincent Amy L. , Perez Daniel R.
Published: October 2018

The complex and continuous antigenic evolution of IAVs remains a major hurdle for vaccine selection and effective vaccination. On the hemagglutinin (HA) of the H3N2 IAVs, the amino acid substitution N 145 K causes significant antigenic changes. We show that amino acid 145 displays remarkable amino acid plasticityin vitro, tolerating multiple amino acid substitutions, many of which have not yet been observed in nature. Mutant viruses carrying substitutions at residue 145 showed no major impairment in virus replication in the presence of lower receptor binding avidity. However, their antigenic characterization confirmed the impact of the 145 K substitution in antibody immunodominance. We provide a better understanding of the functional effects of amino acid substitutions implicated in antigenic drift and its consequences for receptor binding and antigenicity. The mutation analyses presented in this report represent a significant data set to aid and test the ability of computational approaches to predict binding of glycans and in antigenic cartography analyses.
Isolation of Neutralizing Monoclonal Antibodies to Human Astrovirus and Characterization of Virus Variants That Escape Neutralization
Authors: Espinosa Rafaela , López Tomás , Bogdanoff Walter A. , Espinoza Marco A. , López Susana , DuBois Rebecca M. , Arias Carlos F.
Published: October 2018

Human astroviruses (HAstVs) are common etiological agents of acute gastroenteritis in children, the elderly, and immunocompromised patients; some virus strains have also been associated with neurological disease. Despite their medical importance, the study of these pathogens has advanced at a slow pace. In this work, we produced neutralizing antibodies to the virus and mapped the epitopes they recognize on the virus capsid. These studies provide the basis for development of subunit vaccines that induce neutralizing antibodies, as well as tools to explore the development of a specific antibody therapy for astrovirus disease. Our results also establish a platform to advance our knowledge on HAstV cell binding and entry.
A Defect in Influenza A Virus Particle Assembly Specific to Primary Human Macrophages
Authors: Bedi Sukhmani , Noda Takeshi , Kawaoka Yoshihiro , Ono Akira
Published: October 2018

Identification of host cell determinants promoting or suppressing replication of viruses has been aided by analyses of host cells that impose inherent blocks on viral replication. In this study, we show that primary human MDM, which are not permissive to IAV replication, fail to support virus particle formation. This defect is specific to primary human macrophages, since a human monocytic cell line differentiated to macrophage-like cells supports IAV particle formation. We further identified association between two viral transmembrane proteins, HA and M2, on the cell surface as a discrete assembly step, which is defective in MDM. Defective HA-M2 association and particle budding, but not virus release, in MDM are rescued by disruption of actin cytoskeleton, revealing a previously unknown, negative role for actin, which specifically targets an early step in the multistep IAV production. Overall, our study uncovered a host-mediated restriction of association between viral transmembrane components during IAV assembly.
Who's Your DadA?d-Alanine Levels Regulate Bacterial Stiffness
Authors: Odermatt Pascal D. , Arjes Heidi A. , Chang Fred , Huang Kerwyn Casey
Published: October 2018

A central question in mechanobiology is how cellular-scale structures are established and regulated. In bacteria, the cell envelope is essential for mechanical integrity, protecting against environmental stresses and bearing the load from high turgor pressures.
Metapopulation Structure of CRISPR-Cas Immunity in
Pseudomonas aeruginosa
and Its Viruses
Authors: England Whitney E. , Kim Ted , Whitaker Rachel J.
Published: October 2018

Pseudomonas aeruginosa
is a widespread opportunistic pathogen and a major cause of morbidity and mortality in cystic fibrosis patients. Microbe-virus interactions play a critical role in shaping microbial populations, as viral infections can kill microbial populations or contribute to gene flow among microbes. Investigating how
P. aeruginosa
uses its CRISPR immune system to evade viral infection aids our understanding of how this organism spreads and evolves alongside its viruses in humans and the environment. Here, we identify patterns of CRISPR targeting and immunity that indicate
P. aeruginosa
and its viruses evolve in both a broad global population and in isolated human “islands.” These data set the stage for exploring metapopulation dynamics occurring within and between isolated “island” populations associated with CF patients, an essential step to inform future work predicting the specificity and efficacy of virus therapy and the spread of invasive viral elements and pathogenic epidemic bacterial strains.
Expression of death receptor 3 (DR3) on peripheral blood mononuclear cells of patients with psoriasis vulgaris
Authors: Li Lin , Lu Yonghong , Fu Lixin , Zhou Peimei , Zhang Liwen , Wang Wenju , Nie Jianjun , Zhang Dawei , Liu Yan , Wu Bo , Zhou Yi , Chen Tao
Published: October 2018

Background

A series of previous reports indicated that tumour necrosis factor-like ligand 1A (TL1A) and its receptor death receptor 3 (DR3) are involved in the pathogenesis of psoriasis vulgaris (PV), which is a common chronic skin disease accompanied by a number of comorbidities, although their exact roles remain unclear. Our previous studies demonstrated that serum TL1A levels were substantially elevated in patients with PV, but the detection of DR3 expression in peripheral blood mononuclear cells (PBMCs) of patients with PV had not been reported. Therefore, we detected DR3 expression on CD4+, CD8+, CD14+ and CD19+ PBMCs of patients with PV, atopic dermatitis (AD) and healthy volunteers.

Methods

Blood samples were collected from participants with PV before and after treatment. Then, PBMCs from patients with PV were isolated. The Psoriasis Area Severity Index (PASI) was used to assess severity in patients with PV. The DR3 on CD4+, CD8+, CD14+ and CD19+ PBMCs were detected by flow cytometry analysis. Pearson’s correlation analysis was then used to investigate the relationship between DR3 expression and PASI scores in patients with PV.

Results

Comparing with the healthy volunteers and patients with AD, the percentage of DR3-expressing on CD8+ and CD14+ PBMCs in patients with PV was elevated, but the percentage of DR3-expressing on CD8+ and CD14+ cells decreased after anti-inflammatory treatment, which was correlated with PASI scores.

Conclusions

Taken together, these findings suggest that DR3 may play a key role in the pathogenesis of PV.
Modeling and forecasting multifractal wavelet scale: Western market versus eastern market
Authors: Oral Emrah , Unal Gazanfer
Published: October 2018

This leading primary study is about modeling multifractal wavelet scale time series data using multiple wavelet coherence (MWC), continuous wavelet transform (CWT) and multifractal detrended fluctuation analysis (MFDFA) and forecasting with vector autoregressive fractionally integrated moving average (VARFIMA) model. The data is acquired from Yahoo Finances!, which is composed of 1671 daily stock market of eastern (NIKKEI, TAIEX, KOPSI) and western (SP500, FTSE, DAX) markets. Once the co-movement dependencies on time-frequency space are determined with MWC, the coherent data is extracted out of raw data at a certain scale by using CWT. The multifractal behavior of the extracted series is verified by MFDFA and its local Hurst exponents have been calculated obtaining root mean square of residuals at each scale. This inter-calculated fluctuation function time series has been re-scaled and used to estimate the process with VARFIMA model and forecasted accordingly. The results have shown that the direction of price change is determined without difficulty and the efficiency of forecasting has been substantially increased using highly correlated multifractal wavelet scale time series data.
Structure, magnetic properties and thermal expansion of Mn3PtNx (0 ≤ x ≤ 1.0) compounds
Authors: Chou Ruihua , Sun Ying , Lu Huiqing , Lu Guang-Hong
Published: October 2018

In this work, Mn3PtN[Formula: see text] (x = 0, 0.25, 0.5, 0.75 and 1.0) compounds were prepared by solid state reaction method. The structure, magnetic properties and thermal expansion behaviors of Mn3PtN[Formula: see text] compounds with different nitrogen content were systematically investigated. Mn3PtN has typical antiperovskite cubic structure with space group Pm-3m (221). With decreasing nitrogen content, the crystal structure changes to hexagonal with space group P63/mmc when the value of x decreases to x = 0.25, and then back to cubic with Fm3m at x = 0. All of the obtained Mn3PtN[Formula: see text] compound exhibit the magnetic transition from antiferromagnetic (AFM) to paramagnetic (PM). Moreover, another transition from AFM1 to AFM2 at lower temperature was also observed in Mn3Pt. The experimental results indicate that the magnetic transition induced abnormal thermal expansion behavior in Mn3PtN[Formula: see text]. Especially, a typical giant thermal expansion behavior of about [Formula: see text]8‰ volume change arising from the magneto-volume effect at 411 K is observed in Mn3Pt compound. The obtained results imply that this kind of compounds is a strong lattice–spin correlation system.
Approximate Quantification of Higher-Mode Effects on Seismic Demands of Buildings
Authors: Lin Jui-Liang
Published: October 2018

Quantifying the higher-mode effects on the seismic demands of buildings may benefit not only the awareness of characteristics of the seismic responses of buildings, but also the development of rapid/simplified methods for the seismic assessment of buildings. This study proposes an approach that is applicable for quantifying the aforementioned effects, covering the full range of building heights and deformation types. The vehicle used in this proposed approach is the generalized building model, which has been modified from the conventional cantilever beam model. In addition to building height and deformation type, the strength ratio of each vibration mode and the site class of buildings are the parameters considered in this study. The higher-mode effects on floor displacements, inter-story drift ratios, floor accelerations, and base shears with relation to the aforementioned parameters are investigated. Finally, the proposed approach is verified via the investigation of the higher-mode effects of a 20-story exemplar building.
Sensitivity Analysis of Cable Parameters on Tension of a Suspended Cable under Combination Resonances
Authors: Kim Kyu Won , Park No-Cheol , Song Weon Keun , Kim Moon Kyum , Parnichkun Manukid
Published: October 2018

This paper studies the vibration of a suspended cable with small sag excited by a second excitation (normal) mode causing combination resonance in the three modes, i.e. tangent, normal and bi-normal modes. The displacement response spectra in the time domain and phase portraits are provided as evidence of the transition from the unstable steady-state motion to the stable one for nonlinear cable oscillation. A nondimensional equation for the cable tension is established with its variation evaluated for the unstable zone. The half-normalized sensitivity analysis of cable parameters, such as damping coefficient, excitation amplitude, arc length parameter and initial conditions, for their influence on cable tension is conducted in the time domain by a direct integration method. Also, the characteristics of the dynamic sensitivity of cable tension to the parameters are discussed. As a result, a sensitivity ranking chart is prepared based on the sensitivity analyses for the parameters considered. It is clearly revealed that cable tension is very sensitive to tangent and normal initial displacements in spite of their small values, whereas the same is not true for the arc length parameter and bi-normal damping coefficient. To verify the sensitivity analysis algorithm, a forced Rayleigh oscillator is introduced. A feasibility study using the oscillator shows that the numerical results obtained are in good qualitative agreement with the analytical predictions, implying that the associated algorithm works well.
Evaluation of Biomechanical Health Degree of Peri-Implant Bone Through Finite Element Analysis: A First Approach
Authors: Lin Junxiong , Zhang Ge , Jiang Zhenyu , Tang Liqun , Lian Keqian
Published: October 2018

The biomechanical health degree of peri-implant bone plays a critical role during the service of implants. This paper presents a preliminary exploration of the quantitative evaluation of the biomechanical health degree for the bone tissues around dental implant through finite element method. The finite element model of a part of mandible with three molars is constructed based on computer tomography scan image as a control sample, which is supposed to represent a healthy state. The model of treated mandible is made by replacing the middle tooth in the healthy model with a commercial implant. A regional average strain energy density (RASED) is proposed as a more accurate index to describe the stress state of peri-implant bone tissues, compared with the widely used maximum equivalent von Mises stress. The simulation shows that the stress state in peri-implant bone, i.e., the distribution and level of stress, is highly dependent on the modulus of implant material. Among the implants made of materials with various moduli, including Ti, stainless steel, zirconia, porous Ti, dentin material and polyether-ether-ketone (PEEK), the ones with medium modulus (15–40[Formula: see text]GPa) are found to achieve relatively healthy stress states. This study provides an effective tool to assess the risk of overloading or stress shielding in peri-implant bone tissues. It demonstrates a great potential in the optimization of design, production and usage of implants.
Mechanical Behavior Modeling of Hyperelastic Transversely Isotropic Materials Based on a New Polyconvex Strain Energy Function
Authors: Taghizadeh D. M. , Darijani H.
Published: October 2018

In this paper, the mechanical behavior of incompressible transversely isotropic materials is modeled using a strain energy density in the framework of Ball’s theory. Based on this profound theory and with respect to physical and mathematical aspects of deformation invariants, a new polyconvex constitutive model is proposed for the mechanical behavior of these materials. From the physical viewpoint, it is assumed that the proposed model is additively decomposed into three parts nominally representing the energy contributions from the matrix, fiber and fiber–matrix interaction where each of the parts should be presented in terms of the invariants consistent with the physics of the deformation. From the mathematical viewpoint, the proposed model satisfies the fundamental postulates on the form of strain energy density, specially polyconvexity and coercivity constraints. Indeed, polyconvexity ensures ellipticity condition, which in turn provides material stability and in combination with coercivity condition, guarantees the existence of the global minimizer of the total energy. In order to evaluate the performance of the proposed strain energy density function, some test data of incompressible transverse materials with pure homogeneous deformations are used. It is shown that there is a good agreement between the test data and the obtained results from the proposed model. At the end, the performance of the proposed model in the prediction of the material behavior is evaluated rather than other models for two representative problems.
Recommending Who to Follow in the Software Engineering Twitter Space
Authors: Sharma Abhishek , Tian Yuan , Sulistya Agus , Wijedasa Dinusha , Lo David
Published: October 2018

With the advent of social media, developers are increasingly using it in their software development activities. Twitter is one of the popular social mediums used by developers. A recent study by Singer et al. found that software developers use Twitter to “keep up with the fast-paced development landscape.” Unfortunately, due to the general-purpose nature of Twitter, it’s challenging for developers to use Twitter for their development activities. Our survey with 36 developers who use Twitter in their development activities highlights that developers are interested in following specialized software gurus who share relevant technical tweets.

To help developers perform this task, in this work we propose a recommendation system to identify specialized software gurus. Our approach first extracts different kinds of features that characterize a Twitter user and then employs a two-stage classification approach to generate a discriminative model, which can differentiate specialized software gurus in a particular domain from other Twitter users that generate domain-related tweets (aka domain-related Twitter users). We have investigated the effectiveness of our approach in finding specialized software gurus for four different domains (JavaScript, Android, Python, and Linux) on a dataset of 86,824 Twitter users who generate 5,517,878 tweets over 1 month. Our approach can differentiate specialized software experts from other domain-related Twitter users with an F-Measure of up to 0.820. Compared with existing Twitter domain expert recommendation approaches, our proposed approach can outperform their F-Measure by at least 7.63%.
Events
Authors: Rovatsos Michael
Published: October 2018

This section features information about up-coming events relevant to the readers of AI Matters, including those supported by SIGAI. We would love to hear from you if you are are organizing an event and would be interested in cooperating with SIGAI, or if you have announcements relevant to SIGAI. For more information about conference support visit sigai.acm.org/activities/requesting_sponsor-ship.html.
Word for Word: Verbatim as Political Technologies
Authors: Inoue Miyako
Published: October 2018

Verbatim—word for word—is assumed to be a text that faithfully captures and represents a discursive event that took place in time and space, which would otherwise be ephemeral and unrepeatable. In modern societies, verbatim stands in for durable indexicality and materializes the social epistemology of evidence, accountability, and authenticity. Today's ubiquitous presence of recording technologies amplifies the conviction that the production of verbatim as in the conversion, for example, from speech to writing is unmediated and transparently mechanical. Far from being unremarkable, however, the seemingly unmotivated commensurability between original and copy is an ideological function of social reproduction and institutional power. Building on both classic and contemporary linguistic anthropological and sociolinguistic studies of verbatim texts, this review suggests how ethnographically situated studies of verbatim in its production and process open up cogent historical and political analysis of social institutions and relations and of subject formation through the labor of inscription.
Complementary Role of the Computed Biomodelling through Finite Element Analysis and Computed Tomography for Diagnosis of Transcatheter Heart Valve Thrombosis
Authors: Nappi Francesco , Mazzocchi Laura , Avtaar Singh Sanjeet Singh , Morganti Simone , Sablayrolles Jean-Louis , Acar Christophe , Auricchio Ferdinando
Published: October 2018

Introduction. The TAVR procedure is associated with a substantial risk of thrombosis. Current guidelines recommend catheter-based aortic valve implantation for prohibitive-high-risk patients with severe aortic valve stenosis but acknowledge that the aetiology and mechanism of thrombosis are unclear.Methods. From 2015 to 2018, 607 patients with severe aortic valve stenosis underwent either self-expandable or balloon-expandable catheter-based aortic valve implantation at our institute. A complementary study was designed to support computed tomography as a predictor of complications using an advanced biomodelling process through finite element analysis (FEA). The primary evaluation of study was the thrombosis of the valve at 12 months.Results. At 12 months, 546 patients had normal valvular function. 61 patients had THVT while 6 showed thrombosis and dislodgement with deterioration to NYHA Class IV requiring rehospitalization. The FEA biomodelling revealed a strong link between solid uncrushed calcifications, delayed dislodgement of TAVR and late thrombosis. We observed an interesting phenomenon of fibrosis/calcification originating at the level of the misplaced valve, which was the primary cause of coronary obstruction.Conclusion. The use of cardiac CT and predictive biomodelling should be integrated into routine practice for the selection of TAVR candidates and as a predictor of negative outcomes given the lack of accurate investigations available. This would assist in effective decision-making and diagnosis especially in a high-risk cohort of patients.
The Biology and Role of Interleukin-32 in Tuberculosis
Authors: Li Wu , Deng Wanyan , Xie Jianping
Published: October 2018

Tuberculosis, caused byMycobacterium tuberculosis, remains a leading cause of morbidity and mortality globally, with nearly 10.4 million new cases of incidence and over 1.7 million deaths annually. Drug-resistantM. tuberculosisstrains, especially multidrug-resistant or extensively drug-resistant strains, have further intensified the problem associated with tuberculosis control. Host-directed therapy is a promising alternative for tuberculosis control. IL-32 is increasingly recognized as an important host molecule against tuberculosis. In this review, we highlight the proinflammatory properties of IL-32 and the mode of action of IL-32 in mycobacterial infections to inspire the development of novel immunity-based countermeasures and host-directed therapies against tuberculosis.
Acupoint Therapy on Diabetes Mellitus and Its Common Chronic Complications: A Review of Its Mechanisms
Authors: Feng Yiyi , Fang Yuchen , Wang Yiqin , Hao Yiming
Published: October 2018

Acupoint therapy is one of the therapeutic means in Traditional Chinese Medicine (TCM) concerning acupoints and meridians, including manual acupuncture, electroacupuncture, moxibustion, external application, acupoint injection, and catgut embedding. In the treatment of diabetes and its common chronic complications, acupoint therapy has proved to have specific curative effect and notable advantages. Single or combined with western medicine, it has superior efficacy and less side effects than western medicine alone. Studying its mechanism can provide experimental basis for clinical treatment. Relevant researches in the recent 5 years mainly focused on the mechanism of electroacupuncture, point injection, catgut embedding, etc. in the treatment of diabetes and common diabetic complications such as neuropathy, nephropathy, and hepatopathy. The possible theories involve the regulation of nerve conduction, signal pathways, hormone level, protein expression, oxidative stress level, structure restoration, etc. The most studied acupoints are Zusanli (ST36), Shenshu (BL23), Sanyinjiao (SP6), Yishu (EX-B3), and Zhongwan (CV12). However, most of the studies have been based on diabetes model rats rather than clinical trials. Moreover, the mechanism of acupoint therapy treating other chronic complications like diabetic retinopathy and that of other effective methods like pressing ear with beans, auricular points plaster therapy, and external application remain unclear. Therefore, this aspect still awaits further research.
Threshold Secret Sharing Transmission against Passive Eavesdropping in MIMO Wireless Networks
Authors: Myung Jungho , Kim Keunyoung , Kim Taehong
Published: October 2018

We propose a threshold secret sharing scheme for secure communications in multiple input and multiple output wireless networks. In the proposed scheme, the base station divides the secret data into Nmin parts using a polynomial of degree T − 1  (T ≤ Nmin) and transmits the divided data to the legitimate user by beamforming with multiple spatial dimensions. Then, at the user, the secret data can be reconstructed with a sufficient number (≥T) of divided parts by using the Lagrange interpolating polynomial. However, it is difficult for the eavesdropper to correctly estimate the T parts due to the difference between the main channel with beamforming and the eavesdropping channel in the physical layer, which results in the failure of secret data reconstruction. The numerical results show that the eavesdropping probability of the proposed scheme is lower than those of conventional schemes. Moreover, we analyze the symbol‐error‐rate and show that the theoretical result is well aligned with simulation results.
Supply Chain Coordination under Inventory Inaccuracy with RFID Technology
Authors: Lei Quansheng , Zhang Yin , Zhou Lingyu
Published: October 2018

In this paper we consider a two-echelon supply chain under price-dependent demand market and we use RFID to eliminate the effect of inventory inaccuracy. Models are built to evaluate the economic viability and coordination conditions. We analyze two scenarios in which the supply chain is defined, the integrated one and the decentralized one, respectively. For the integrated, we compare the different supply chain revenue with and without RFID technology and then determine the optimal inventory decisions. For the decentralized, we mainly focus on the coordination mechanism by revenue sharing contract under Stackelberg game. By seeking appropriate contract parameters, the supply chain can finally be coordinated while all partners are better off. Furthermore, numerical examples are given to verify our proposition.
Safety Assessment and Risk Estimation for Unmanned Aerial Vehicles Operating in National Airspace System
Authors: Zhang Xuejun , Liu Yang , Zhang Yu , Guan Xiangmin , Delahaye Daniel , Tang Li
Published: October 2018

This paper proposes an effective approach for modelling and assessing the risks associated with unmanned aerial vehicles (UAVs) integrated into national airspace system (NAS). Two critical hazards with UAV operations are considered and analyzed, which are ground impacts and midair collisions. Threats to fatalities that result from the two hazards are the focus in the proposed method. In order to realize ground impact assessment, a multifactor risk model is designed by calculating system reliability required to meet a target level of safety for different UAV categories. Both fixed-wing and rotary-wing UAVs are taken into account under a real scenario that is further partitioned into different zones to make the evaluation more precise. Official territory and population data of the operation scenario are incorporated, as well as UAV self-properties. Casualty area of impacting debris can be obtained as well as the probability of fatal injuries on the ground. Sheltering factors are not neglected and defined as four types based on the real scenario. When midair collision fatality risk is estimated, a model of aircraft collisions based on the density of civil flight in different regions over Chinese airspace is proposed. In the model, a relative collision area and flying speed between UAVs and manned aircraft are constructed to calculate expected frequency of fatalities for each province correspondingly. Truthful data with different numbers of UAVs is incorporated in the model with the expected number of fatalities after a collision is included. Experimental simulations are made to evaluate the ground impacts and midair collisions when UAVs operate in the NAS.
Critical‐Path Aware Scheduling for Latency Efficient Broadcast in Duty‐Cycled Wireless Sensor Networks
Authors: Le Duc-Tai , Im Giyeol , Le Duc Thang , Zalyubovskiy Vyacheslav V. , Kim Dongsoo S. , Choo Hyunseung
Published: October 2018

Minimum latency scheduling has arisen as one of the most crucial problems for broadcasting in duty‐cycled Wireless Sensor Networks (WSNs). Typical solutions for the broadcast scheduling iteratively search for nodes able to transmit a message simultaneously. Other nodes are prevented from transmissions to ensure that there is no collision in a network. Such collision‐preventions result in extra delays for a broadcast and may increase overall latency if the delays occur along critical paths of the network. To facilitate the broadcast latency minimization, we propose a novel approach, critical‐path aware scheduling (CAS), which schedules transmissions with a preference of nodes in critical paths of a duty‐cycled WSN. This paper presents two schemes employing CAS which produce collision‐free and collision‐tolerant broadcast schedules, respectively. The collision‐free CAS scheme guarantees an approximation ratio of (Δ − 1)T in terms of latency, where Δ denotes the maximum node degree in a network. By allowing collision at noncritical nodes, the collision‐tolerant CAS scheme reduces up to 10.2 percent broadcast latency compared with the collision‐free ones while requiring additional transmissions for the noncritical nodes experiencing collisions. Simulation results show that broadcast latencies of the two proposed schemes are significantly shorter than those of the existing methods.
Consequences of Misdiagnosed and Mismanaged Hereditary Angioedema Laryngeal Attacks: An Overview of Cases from the Romanian Registry
Authors: Moldovan Dumitru , Bara Noémi , Nădășan Valentin , Gábos Gabriella , Mihály Enikő
Published: October 2018

Emergency department (ED) physicians frequently encounter patients presenting with angioedema. Most of these involve histamine-mediated angioedema; however, less common forms of angioedema (bradykinin-mediated) also occur. It is vital physicians correctly recognize and treat this; particularly since bradykinin-mediated angioedema does not respond to antihistamines, corticosteroids or epinephrine and hereditary angioedema (HAE) laryngeal attacks can be fatal. Here we present four case reports illustrating how failures in recognizing, managing, and treating laryngeal edema due to HAE led to asphyxiation and death of the patient. Recognition of the specific type of angioedema is critical for rapid and effective treatment of HAE attacks. Bradykinin-mediated angioedema should be efficiently differentiated from the most common histamine-mediated form. Improved awareness of HAE and the associated risk of life-threatening laryngeal edema among emergency physicians, patients, and relatives and clear ED treatment protocols are warranted. Moreover, appropriate treatments should be readily available to reduce fatalities associated with laryngeal edema.
Gastric Peroral Endoscopic Myotomy (G-POEM) as a Treatment for Refractory Gastroparesis: Long-Term Outcomes
Authors: Xu Jiaxin , Chen Tianyin , Elkholy Shaimaa , Xu Meidong , Zhong Yunshi , Zhang Yiqun , Chen Weifeng , Qin Wenzheng , Cai Mingyan , Zhou Pinghong
Published: October 2018

Background and Aims. Gastric peroral endoscopic myotomy (G-POEM) has been regarded as a novel and minimally invasive therapy for refractory gastroparesis. This study reports the long-term outcomes and possible predictive factors for successful outcomes after G-POEM in an Asian population. Methods. This is a retrospective single-centre study of 16 patients who underwent G-POEM for refractory gastroparesis from August 2016 to October 2017. This study included 11 males and 5 females; in addition, 13 patients had postsurgical gastroparesis, and 3 patients had diabetes. The patients included had severe and refractory gastroparesis, as indicated by a Gastroparesis Cardinal Symptom Index (GCSI) score ≥20, and evidence of a delay on gastric emptying scintigraphy (GES). The primary outcome parameter was an assessment of the long-term clinical efficacy of the procedure. The secondary outcome parameter was the detection of possible predictive factors for success and the determination of cut-off values for such predictors. Results. Technical success was achieved in 100% of the patients, with a mean procedure time of 45.25±12.96 min. The long-term clinical response was assessed in all patients during a median follow-up of 14.5 months. Clinical success was achieved in 13 (81.25%) patients. There was a significant reduction in the GCSI scores and GES values after the procedure compared to the baseline values, with P values of <0.0001 and 0.012, respectively. Univariate regression analysis showed that the GCSI and GES had significant associations with the future clinical outcomes of the patients, but this finding was not confirmed in multivariate analysis. A GCSI cut-off score of ≤30 had a high sensitivity and a negative predictive value (NPV) of 100% for predicting a successful procedure. GES (half emptying time ≤221.6 min and 2-hour retention ≤78.6%) had a high specificity and a positive predictive value (PPV) of 100%. Conclusions. G-POEM is a safe and effective treatment option with a long-term efficacy of 81.6%. GCSI and GES could serve as good predictive measures.