bluuebunny/crossref_metadata_2025 huggingface dataset:
The Roc‐COR tandem domain of leucine‐rich repeat kinase 2 forms dimers and exhibits conventional Ras‐like GTPase properties
Authors: Mills Ryan D. , Liang Lung‐Yu , Lio Daisy Sio‐Seng , Mok Yee‐Foong , Mulhern Terrence D. , Cao George , Griffin Michael , Kenche Vijaya B. , Culvenor Janetta G. , Cheng Heung‐Chin
Published: August 2018

The Parkinson's disease (PD)‐causative leucine‐rich repeat kinase 2 (LRRK2) belongs to the Roco family of G‐proteins comprising a Ras‐of‐complex (Roc) domain followed by a C‐terminal of Roc (COR) domain in tandem (called Roc‐COR domain). Two prokaryotic Roc‐COR domains have been characterized as ‘G proteins activated by guanine nucleotide‐dependent dimerization’ (GADs), which require dimerization for activation of their GTPase activity and bind guanine nucleotides with relatively low affinities. Additionally, LRRK2 Roc domain in isolation binds guanine nucleotides with relatively low affinities. As such, LRRK2 GTPase domain was predicted to be a GAD. Herein, we describe the design and high‐level expression of human LRRK2 Roc‐COR domain (LRRK2 Roc‐COR). Biochemical analyses of LRRK2 Roc‐COR reveal that it forms homodimers, with the C‐terminal portion of COR mediating its dimerization. Furthermore, it co‐purifies and binds Mg2+GTP/GDP at 1 : 1 stoichiometry, and it hydrolyzes GTP with Km and kcat of 22 nM and 4.70 × 10−4 min−1, respectively. Thus, even though LRRK2 Roc‐COR forms GAD‐like homodimers, it exhibits conventional Ras‐like GTPase properties, with high‐affinity binding of Mg2+‐GTP/GDP and low intrinsic catalytic activity. The PD‐causative Y1699C mutation mapped to the COR domain was previously reported to reduce the GTPase activity of full‐length LRRK2. In contrast, this mutation induces no change in the GTPase activity, and only slight perturbations in the secondary structure contents of LRRK2 Roc‐COR. As this mutation does not directly affect the GTPase activity of the isolated Roc‐COR tandem, it is possible that the effects of this mutation on full‐length LRRK2 occur via other functional domains.

Open Practices

Open Science: This manuscript was awarded with the Open Materials Badge.

For more information see: https://cos.io/our-services/open-science-badges/

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Meeting patients’ spiritual needs during end‐of‐life care: A qualitative study of nurses’ and healthcare professionals’ perceptions of spiritual care training
Authors: O'Brien Mary R. , Kinloch Karen , Groves Karen E. , Jack Barbara A.
Published: August 2018

Aims and objectives

To explore nurses’ and healthcare professionals’ perceptions of spiritual care and the impact of spiritual care training on their clinical roles.

Background

Many nurses and healthcare professionals feel unprepared and lack confidence, competence and skills, to recognise, assess and address patients’ spiritual issues. Patients with unmet spiritual needs are at increased risk of poorer psychological outcomes, diminished quality of life and reduced sense of spiritual peace. There are implications for patient care if nurses and healthcare professionals cannot attend to patients’ spiritual needs.

Design

A qualitative methodology was adopted.

Methods

Recruitment was purposive. A total of 21 generalist and specialist nursing and healthcare professionals from North West and South West England, who undertook spiritual care training between 2015–2017, were recruited. Participants were required to be a minimum of 3 months posttraining. Digitally audio‐recorded semistructured interviews lasting 11–40 min were undertaken in 2016–2017. Data were subjected to thematic analysis. Ethical committee approval was obtained. COREQ reporting guidelines were utilised.

Results

Two main themes were identified, recognising spirituality, with subthemes of what spirituality means and what matters, and supporting spiritual needs, with subthemes of recognition of spiritual distress, communication skills, not having the answers and going beyond the physical.

Conclusions

Supporting patients as they approach the end of life needs a skilled workforce; acknowledging the importance of spiritual care and having skills to address it are central to delivery of best holistic care.

Relevance to clinical practice

Spiritual care is as important as physical care and supporting patients spiritually as they approach the end of life is vital. Appropriately trained, nurses and healthcare professionals are better able to assess, explore and meet patients’ spiritual needs.
Dilating and fracturing side struts of open cell stents frequently used in pediatric cardiac interventions—An in vitro study
Authors: Krasemann Thomas , Kruit Marco N. , van der Mark Arthur E. , Zeggelaar Martijn , Dalinghaus Michiel , van Beynum Ingrid M.
Published: August 2018

Background

Open cell stents are frequently used in interventional therapy of congenital heart disease. Overstenting of vessel branches may necessitate strut dilation.

Methods and Results

The strut size achievable in Bard Valeo and Cook Formula stents, and the pressure necessary to fracture struts was assessed. In addition, a self expanding stent (Optimed SinusflexDS) was also tested. With the original balloon at nominal pressure, in Valeo stents side struts could be dilated to approximately 90% of the nominal stent diameter, in Formula stents to approximately 80%. With larger high pressure woven balloons, strut size increased to approximately 125% in Valeo stents, and to approximately 105% in the Formula. Strut fracture can connect two adjoining struts. Pressures were dependent on the balloon utilized. Sidestruts of the Sinusflex could lastingly overdilated with large balloons only.

Conclusion

Dilation and overdilation of side struts in open cell stents can be achieved. Dependent on the clinical context, the original balloon used to place the premounted stent can be used to achieve strut dilation, but woven high pressure balloons maybe safer for patients. Should a larger diameter be required, these high pressure woven balloons can achieve bigger diameters and even strut fracture.
Melatonin modulates autophagy and inflammation protecting human placental trophoblast from hypoxia/reoxygenation
Authors: Sagrillo‐Fagundes Lucas , Assunção Salustiano Eugênia M. , Ruano Rodrigo , Markus Regina P. , Vaillancourt Cathy
Published: August 2018

Melatonin has been proposed as a possible treatment for the deleterious effects of hypoxia/reoxygenation (H/R), such as autophagy, inflammation, and apoptosis. Pathological pregnancies, such as preeclampsia, are associated with placental H/R, and decreased placental melatonin synthesis as well as lower melatonin levels in the placenta and maternal plasma. However, the effects of exogenous melatonin on inflammation and autophagy induced by pregnancy complications associated with H/R await investigation. This study aimed to determine as to whether melatonin protects human primary villous trophoblasts against H/R‐induced autophagy, inflammation, and apoptosis. Human primary villous cytotrophoblasts were isolated and immunopurified from normal term placentas. These cells were then exposed or not to 1 mmol/L melatonin for 72 hour in normoxia (8% O2), thereby inducing differentiation into syncytiotrophoblast that was then exposed to H/R (0.5% O2, for 4 hour) or normoxia. H/R decreased endogenous melatonin synthesis (by 68%) and interleukin (IL)‐10 levels (by 72%), coupled to increased tumor necrosis factor (TNF) (by 114%), IL‐6 (by 55%), and NFκB (by 399%), compared to normoxia. Melatonin treatment reversed the H/R effect, restoring IL‐10, TNF, and IL‐6 levels to those of the normoxia condition. Melatonin, as well as NFκB inhibition, enhanced autophagy activation, consequently increasing syncytiotrophoblast survival in H/R conditions. This study suggests that H/R, which is present in pregnancy complications, inhibits endogenous melatonin production, thereby contributing to reduced syncytiotrophoblast viability. Results indicate that exogenous melatonin treatment may afford protection against H/R‐induced damage, thereby enhancing placental cell survival, and contributing to improved fetal outcomes.
Option pricing under fast‐varying long‐memory stochastic volatility
Authors: Garnier Josselin , Sølna Knut
Published: August 2018

Recent empirical studies suggest that the volatility of an underlying price process may have correlations that decay slowly under certain market conditions. In this paper, the volatility is modeled as a stationary process with long‐range correlation properties in order to capture such a situation, and we consider European option pricing. This means that the volatility process is neither a Markov process nor a martingale. However, by exploiting the fact that the price process is still a semimartingale and accordingly using the martingale method, we can obtain an analytical expression for the option price in the regime where the volatility process is fast mean reverting. The volatility process is modeled as a smooth and bounded function of a fractional Ornstein–Uhlenbeck process. We give the expression for the implied volatility, which has a fractional term structure.
The nation in the region: flamenco andcanzone napoletanaas national icons in modern Spain and Italy (1880–1922)
Authors: Conversi Daniele
Published: August 2018

Although the relationship between music and nationalism has been at the centre of recent cross‐disciplinary research, many areas remain unexplored. Among them are forms of ‘national music’ that nest overlapping identities, functioning simultaneously as vehicles of regional, ethnic, urban, global and diasporic belongings. This article focuses on the national dimension of these multilevel identities, concentrating on the swings and transmigrations between the national and the regional. It compares two Mediterranean traditions which, particularly between the late nineteenth and early twentieth centuries, have served as multilevel identifiers of national and regional belongings:flamencoandcanzone napoletana(Neapolitan song). I argue that, besides geographically bounded identities, both genres were constructed as ‘national’ primarily abroad, rather than in their home countries, thus contributing to a theory of the ‘international’ dimension of ‘national’ music. In the case of flamenco, I focus on the irradiation centre of the time, Paris, although the modern notion of musical Spanishness was first associated with national identity in Russia. Thecanzoneconsolidated its international position mostly through the Italian diaspora, achieving a much wider reach than is ordinarily thought, both nationally and globally.
Walker Connor's political psychology
Authors: Kaufman Stuart J.
Published: August 2018

In a 2002 overview, Daniele Conversi rightly highlights ‘Nationalism as an emotional bond’ as a central theme in Walker Connor's works. Nearly half a century on from Connor's initial assertions, the discipline of psychology has made important strides in understanding the social‐psychological dynamics that influence nationalist feelings. Building on this base of psychological evidence, this essay asks two questions. First, to what degree are Connor's claims supported by or compatible with what psychologists now know? Second, to the extent that Connor's arguments are correct, to what degree have scholarly understandings of nationalist politics recognised the implications of Connor's insights? I conclude that Connor's insights stand up remarkably well, but few have picked up on them, to the lasting detriment of our field of study.
Salivary proteins and peptides in the aetiology of caries in children: Systematic literature review
Authors: Piekoszewska‐Ziętek Paula , Turska‐Szybka Anna , Olczak‐Kowalczyk Dorota
Published: August 2018

Background

To assess the relationship of chosen salivary proteins and peptides levels with the occurrence of caries in children.

Methods

PubMed, MEDLINE and EMBASE databases from 2000 to 2018 were researched for original observational studies published in English. The risk of bias and quality of the included papers were assessed regarding the guidelines by Fowkes and Fulton.

Results

Twenty‐two studies were included in the review, from which the issue of glycoproteins (including immunoglobulins), AMPs and salivary enzymes was discussed. The research involved primary dentition (13 papers), as well as mixed (7) and permanent dentition (5). Caries assessment included visual inspection, dmft/s and DMFT/S indexed; quantity of Streptococcus mutans and Lactobacillus spp. bacteria; and caries risk assessment.

Discussion

The results of studies regarding the connection between salivary peptides and proteins and caries development in children are promising; however, further investigations should be undertaken. The majority of studies included are case–control and cross‐sectional; however, it is necessary to conduct more cohort studies with adequate follow‐up prior to considering this as markers for caries risk assessment.
DNA vaccine ROP29 from Toxoplasma gondii containing R848 enhances protective immunity in mice
Authors: Lu Gang , Zhou Jian , Zhao Ying hui , Wang Lin
Published: August 2018

Aims

Toxoplasma gondii is an intracellular parasite that causes a global epidemic parasitic disease. Studies using DNA vaccines for the control of toxoplasmosis have made considerable progress. ROP proteins were proven to be excellent candidates for T. gondii DNA vaccine development.

Methods and Results

Here, a ROP29 DNA vaccine was successfully produced and injected into mice in combination with R848 to evaluate its ability to provide protection against T. gondii challenge. Compared with other mice, the mice injected with R848/pROP29 produced higher levels of IgG, IgG2a, interleukin (IL)‐12, and interferon gamma (IFN‐γ). Moreover, after a challenge of 20 T. gondii cysts, the number of brain cysts was lower in the R848/pROP29‐immunized mice than in the other experimental mice.

Conclusions

R848 could improve the productions of IL‐12 and IFN‐γ, thus enhancing the immune responses stimulated by the pROP29 DNA vaccine.
Influence of exogenously applied nitric oxide on strawberry (Fragaria × ananassa) plants grown under iron deficiency and/or saline stress
Authors: Kaya Cengiz , Akram Nudrat A. , Ashraf Muhammad
Published: August 2018

A study was carried out to assess the protective effects of exogenously applied nitric oxide (NO) in the form of its donor sodium nitroprusside (SNP) to strawberry seedlings (Fragaria × ananassacv. Camarosa) grown under iron deficiency (ID), salinity stress or combination of both. The experimental design contained control, 0.1 mM FeSO4(ID, Fe deficiency); 50 mM NaCl (S, Salinity) and ID + S. Plants were sprayed with 0.1 mM SNP or 0.1 mM sodium ferrocyanide, an analogue of SNP containing no NO. The deleterious effects of ID + S treatments on plant fresh and dry matters, total chlorophyll and chlorophyll fluorescence were more striking than those caused by the ID or S treatment alone. Furthermore, combination of salinity and iron stress exacerbated electrolyte leakage (EL) and the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in plant leaves compared to those in plants grown with either of the single stresses. NO treatment effectively reduced EL, MDA and H2O2in plants grown under stress conditions applied singly or in combination. Salt stress alone and with ID reduced the superoxide dismutase (EC1.15.1.1) and catalase (EC 1.11.1.6) activities but increased that of POD (EC 1.17.1.7). Exogenously applied NO led to significant changes in antioxidant enzyme activities in either ID or S than those by ID+S. Overall, exogenously applied NO was more effective in mitigating the stress‐induced adverse effects on the strawberry plants exposed to a single stress than those due to the combination of both stresses.
Past Developments and Current Advancements in Unsteady Pressure Measurements in Turbomachines
Authors: Lepicovsky Jan , Simurda David
Published: August 2018

The aim of this paper is to review, summarize, and record long-term experience with development and application of aerodynamic probes with built-in miniature pressure transducers for unsteady pressure measurement and industrial research in turbomachine components. The focus of the first half of the paper is on the work performed at VZLU Prague, Czech Republic (Secs. 3–8). The latest development in unsteady pressure measurement techniques and data reduction methodology suitable for future research in highly loaded, high-speed turbine engine components performed at NASA GRC Cleveland, OH, is reported in Secs. 8–15 of this paper. Excellent reviews of similar activities at ETH Zürich, Switzerland by Kupferschmied, et al. (2000, “Time-Resolved Flow Measurements With Fast-Response Aerodynamic Probes in Turbomachines,” Meas. Sci. Technol., 11(7), pp. 1036–1054) and at VKI Rhode-Sain-Genèse, Belgium by Sieverding, et al. (2000, “Measurement Techniques for Unsteady Flows in Turbomachines,” Exp. Fluids, 28(4), pp. 285–321) were already reported and are acknowledged here. A short list of reported accomplishments achieved by other researchers at various laboratories is also reported for completeness. The authors apologize to those whose contributions are not reported here. It is just an unfortunate oversight, not an intentional omission.
Computational Fluid Dynamic Study for aTAA Hemodynamics: An Integrated Image-Based and Radial Basis Functions Mesh Morphing Approach
Authors: Capellini Katia , Vignali Emanuele , Costa Emiliano , Gasparotti Emanuele , Biancolini Marco Evangelos , Landini Luigi , Positano Vincenzo , Celi Simona
Published: August 2018

We present a novel framework for the fluid dynamics analysis of healthy subjects and patients affected by ascending thoracic aorta aneurysm (aTAA). Our aim is to obtain indications about the effect of a bulge on the hemodynamic environment at different enlargements. Three-dimensional (3D) surface models defined from healthy subjects and patients with aTAA, selected for surgical repair, were generated. A representative shape model for both healthy and pathological groups has been identified. A morphing technique based on radial basis functions (RBF) was applied to mold the shape relative to healthy patient into the representative shape of aTAA dataset to enable the parametric simulation of the aTAA formation. Computational fluid dynamics (CFD) simulations were performed by means of a finite volume solver using the mean boundary conditions obtained from three-dimensional (PC-MRI) acquisition. Blood flow helicity and flow descriptors were assessed for all the investigated models. The feasibility of the proposed integrated approach pertaining the coupling between an RBF morphing technique and CFD simulation for aTAA was demonstrated. Significant hemodynamic changes appear at the 60% of the bulge progression. An impingement of the flow toward the bulge was observed by analyzing the normalized flow eccentricity (NFE) index.
Influence of Uncertainty in Selected Musculoskeletal Model Parameters on Muscle Forces Estimated in Inverse Dynamics-Based Static Optimization and Hybrid Approach
Authors: Żuk Magdalena , Syczewska Małgorzata , Pezowicz Celina
Published: August 2018

The purpose of the current study was to investigate the robustness of dynamic simulation results in the presence of uncertainties resulting from application of a scaled-generic musculoskeletal model instead of a subject-specific model as well as the effect of the choice of simulation method on the obtained muscle forces. The performed sensitivity analysis consisted of the following multibody parameter modifications: maximum isometric muscle forces, number of muscles, the hip joint center location, segment masses, as well as different dynamic simulation methods, namely static optimization (SO) with three different criteria and a computed muscle control (CMC) algorithm (hybrid approach combining forward and inverse dynamics). Twenty-four different models and fifty-five resultant dynamic simulation data sets were analyzed. The effects of model perturbation on the magnitude and profile of muscle forces were compared. It has been shown that estimated muscle forces are very sensitive to model parameters. The greatest impact was observed in the case of the force magnitude of the muscles generating high forces during gait (regardless of the modification introduced). However, the force profiles of those muscles were preserved. Relatively large differences in muscle forces were observed for different simulation techniques, which included both magnitude and profile of muscle forces. Personalization of model parameters would affect the resultant muscle forces and seems to be necessary to improve general accuracy of the estimated parameters. However, personalization alone will not ensure high accuracy due to the still unresolved muscle force sharing problem.
Conceptual Three-Dimensional Modeling Using Intuitive Gesture-Based Midair Three-Dimensional Sketching Technique
Authors: Huang Jinmiao , Rai Rahul
Published: August 2018

We introduce an intuitive gesture-based interaction technique for creating and manipulating simple three-dimensional (3D) shapes. Specifically, the developed interface utilizes low-cost depth camera to capture user's hand gesture as the input, maps different gestures to system commands and generates 3D models from midair 3D sketches (as opposed to traditional two-dimensional (2D) sketches). Our primary contribution is in the development of an intuitive gesture-based interface that enables novice users to rapidly construct conceptual 3D models. Our development extends current works by proposing both design and technical solutions to the challenges of the gestural modeling interface for conceptual 3D shapes. The preliminary user study results suggest that the developed framework is intuitive to use and able to create a variety of 3D conceptual models.
A Semi-Analytical Nonlinear Regression Approach for Weld Profile Prediction: A Case of Alternating Current Square Waveform Submerged Arc Welding of Heat Resistant Steel
Authors: Mohanty Uttam Kumar , Sharma Abhay , Nakatani Mitsuyoshi , Kitagawa Akikazu , Tanaka Manabu , Suga Tetsuo
Published: August 2018

The complexity in weld profile caused by abrupt change in polarity in square waveform welding is investigated through the development of a model capable to accurately predict weld profile. A semi-analytical model is conceived wherein characteristic attributes of a composite parabolic–elliptic function, which represent the weld profile, are obtained through nonlinear regression (NLR). The proposed model is demonstrated for its efficacy in the prediction of weld profile over a wide range of welding parameters, vis-à-vis, welding current, frequency, electrode negative (EN) ratio, and welding velocity. The investigation suggests that the center and outer cores of welding arc remains more active during positive and negative polarity, respectively, that leads to distinct macroscopic zones in weld cross section and thus, necessitates a composite profile for representation of weld profile. The intersection of the zones forms a metallurgical notch which the investigation offers a method to estimate and thus control. Unlike the convention continuous arc welding, the waveform arc welding caters welding at higher velocity without compromising the weld penetration and almost abolishing the metallurgical notch as well.
Transient
Behavior of Three-Fluid Cross-Flow Heat Exchanger Under the Influence of Temperature
Nonuniformity
Authors: Aasi Harpreet
Kaur , Mishra Manish
Published: August 2018

A typical three-fluid cross-flow heat exchanger with nonuniform inlet temperature in the central (hot) fluid is considered for the present analysis. Steady and transient state behavior of the heat exchanger is observed for four different temperature nonuniformity models along with step excitation in inlet temperature of the central fluid. Longitudinal heat conduction in the separating walls and the effect of fluid back-mixing along with axial dispersion effect are considered within the fluids with constant thermophysical fluid properties. The solution of governing equations has been obtained using implicit finite difference scheme. Temperature distribution over the separating walls has been depicted providing a clear view of the thermal stresses generated in separating walls. The performance for all the four cross-flow arrangements has been analyzed by comparing that with and without nonuniform conditions. It is found that the nonuniformity in inlet temperature has an adverse effect on the performance of heat exchanger.
Failure Envelopes for Composite Fiber Reinforced Pipe Elbows Subject to Combined Loading—A Numerical Assessment
Authors: Camilleri Duncan , Ellul Brian
Published: August 2018

Composite pipes are currently being used in a multitude of applications varying from civil to oil and gas applications. Pipes are generally connected together by means of pipe elbows that in turn are subjected to bending moment and pressure loading. This study looks into the effect of combined loading on the first ply and ultimate failure load of pipe elbows. The influence of pressure loading followed by a bending moment versus first applying bending moment followed by subsequent pressure loading, on the ultimate catastrophic failure load, is investigated through numerical models. The combined bending moment and pressure load ramping is also studied. Design by analysis finite element damage mechanics numerical methods are applied to investigate post first ply failure (FPF) and stress redistribution. The study shows that different loading combinations can give rise to different damage mechanisms and ultimately failure loads. A safe design load envelope for different fiber-reinforced pipe elbows based on FPF and ultimate catastrophic load is identified and discussed.
A Spectral Numerical Method for Solving Distributed-Order Fractional Initial Value Problems
Authors: Zaky M. A. , Doha E. H. , Tenreiro Machado J. A.
Published: August 2018

In this paper, we construct and analyze a Legendre spectral-collocation method for the numerical solution of distributed-order fractional initial value problems. We first introduce three-term recurrence relations for the fractional integrals of the Legendre polynomial. We then use the properties of the Caputo fractional derivative to reduce the problem into a distributed-order fractional integral equation. We apply the Legendre–Gauss quadrature formula to compute the distributed-order fractional integral and construct the collocation scheme. The convergence of the proposed method is discussed. Numerical results are provided to give insights into the convergence behavior of our method.
On Phase and Anti-Phase Combination Synchronization of Time Delay Nonlinear Systems
Authors: Mahmoud Gamal M. , Arafa Ayman A. , Mahmoud Emad E.
Published: August 2018

Extensive studies have been done on the phenomenon of phase and anti-phase synchronization (APS) between one drive and one response systems. As well as, combination synchronization for chaotic and hyperchaotic systems without delay also has been investigated. Thus, this paper aims to introduce the concept of phase and anti-phase combination synchronization (PCS and APCS) between two drive and one response time delay systems, which are not studied in the literature as far as we know. The analysis of PCS and APCS are carried out using active control technique. An example is given to test the validity of the expressions of control forces to achieve the PCS and APCS of time delay systems. This example is between three different systems. When there is no control, the PCS does not occur where the phase difference is unbounded. The bounded phase difference appears when the control is applied which means that PCS is achieved. The special case which is the combination synchronization is studied as well.
Effect of Longitudinal Variation of Vocal Fold Inner Layer Thickness on Fluid-Structure Interaction During Voice Production
Authors: Jiang Weili , Xue Qian , Zheng Xudong
Published: August 2018

A three-dimensional fluid-structure interaction computational model was used to investigate the effect of the longitudinal variation of vocal fold inner layer thickness on voice production. The computational model coupled a finite element method based continuum vocal fold model and a Navier–Stokes equation based incompressible flow model. Four vocal fold models, one with constant layer thickness and the others with different degrees of layer thickness variation in the longitudinal direction, were studied. It was found that the varied thickness resulted in up to 24% stiffness reduction at the middle and up to 47% stiffness increase near the anterior and posterior ends of the vocal fold; however, the average stiffness was not affected. The fluid-structure interaction simulations on the four models showed that the thickness variation did not affect vibration amplitude, glottal flow rate, and the waveform related parameters. However, it increased glottal angles at the middle of the vocal fold, suggesting that vocal fold vibration amplitude was determined by the average stiffness of the vocal fold, while the glottal angle was determined by the local stiffness. The models with longitudinal variation of layer thickness consumed less energy during the vibrations compared with the constant layer thickness one.
Effect of Thermal Conductivity and Thickness of the Walls on the Natural Convection in a Horizontal Viscoelastic Jeffreys Fluid Layer
Authors: Pérez-Reyes Ildebrando , Dávalos-Orozco Luis Antonio
Published: August 2018

It is a common practice to use ideal thermal boundary conditions to investigate natural convection. These correspond to very good conducting walls and to very bad conducting walls. In particular, this has been the case in natural convection of viscoelastic fluids. In this paper, these conditions are generalized by taking into account the finite thermal conductivities and thicknesses of the walls in the natural convection of a viscoelastic Jeffreys fluid heated from below. The goal is to present more realistic results related to experimental conditions. The critical Rayleigh number Rc, the frequency of oscillation ωc, and the wavenumber kc have been plotted varying the properties of the walls from the case of very good thermal conductivity to very poor thermal conductivity. In order to understand the convective phenomena, two parameters are fixed and the other one varied among the nondimensional relaxation time F, the relative retardation time E, and the Prandtl number Pr of the viscoelastic fluid. The role of the relative retardation time E on the thermal instability is discussed in detail.
An Inverse, Decision-Based Design Method for Integrated Design Exploration of Materials, Products, and Manufacturing Processes
Authors: Nellippallil Anand Balu , Rangaraj Vignesh , Gautham B. P. , Singh Amarendra Kumar , Allen Janet K. , Mistree Farrokh
Published: August 2018

A material's design revolution is underway with a focus to design the material microstructure and processing paths to achieve certain performance requirements of products. A host of manufacturing processes are involved in producing a product. The processing carried out in each process influences its final properties. To couple the material processing-structure-property-performance (PSPP) spaces, models of specific manufacturing processes must be enhanced and integrated using multiscale modeling techniques (vertical integration) and then the input and output of the various manufacturing processes must be integrated to facilitate the flow of information from one process to another (horizontal integration). Together vertical and horizontal integration allows for the decision-based design exploration of the manufacturing process chain in an inverse manner to realize the end product. In this paper, we present an inverse method to achieve the integrated design exploration of materials, products, and manufacturing processes through the vertical and horizontal integration of models. The method is supported by the concept exploration framework (CEF) to systematically explore design alternatives and generate satisficing design solutions. The efficacy of the method is illustrated for a hot rod rolling (HRR) and cooling process chain problem by exploring the processing paths and microstructure in an inverse manner to produce a rod with specific mechanical properties. The proposed method and the exploration framework are generic and support the integrated decision-based design exploration of a process chain to realize an end product by tailoring material microstructures and processing paths.
A Designing and Generating Method for Grinding Relief Surfaces of a Dual-Cone Double-Enveloping Hourglass Worm Gear Hob
Authors: Rui Chengjie , Li Haitao , Yang Jie , Wei Wenjun , Dong Xuezhu
Published: August 2018

Land widths and relief angles of a dual-cone double-enveloping hourglass worm gear hob are important factors that influence the life and the hobbing performance of the hob. Both of them are obtained by generating relief surfaces of the hob. Due to the reason that all teeth of this type of hob have different profiles with each other, all of the relief surfaces are difficult to generate for keeping all cutting teeth with uniformed relief angles and uniformed land widths. For the purpose that land widths and relief angles could be machined precisely, this paper puts forward a designing and generating method for grinding the relief surfaces. The relief surfaces are ground using the same double-cone grinding wheel as grinding the helical surfaces of the worm. Based on the theory of gearing, the mathematical model for grinding relief surfaces is built. Motion parameters when grinding the different points of the land edges on different teeth of the hob are solved. A generating simulation is built by putting those motion parameters into a four-axis hourglass worm-grinding machine. The results of the simulation show that the relief surfaces can be ground continuously and the land widths and the relief angles meet the requirements.
Advances in Diagnostic Methods for Zika Virus Infection
Authors: Herrada Carlos A. , Kabir Md. Alamgir , Altamirano Rommel , Asghar Waseem
Published: August 2018

The Zika virus (ZIKV) is one of the most infamous mosquito-borne flavivirus on recent memory due to its potential association with high mortality rates in fetuses, microcephaly and neurological impairments in neonates, and autoimmune disorders. The severity of the disease, as well as its fast spread over several continents, has urged the World Health Organization (WHO) to declare ZIKV a global health concern. In consequence, over the past couple of years, there has been a significant effort for the development of ZIKV diagnostic methods, vaccine development, and prevention strategies. This review focuses on the most recent aspects of ZIKV research which includes the outbreaks, genome structure, multiplication and propagation of the virus, and more importantly, the development of serological and molecular detection tools such as Zika IgM antibody capture enzyme-linked immunosorbent assay (Zika MAC-ELISA), plaque reduction neutralization test (PRNT), reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR), reverse transcription-loop mediated isothermal amplification (RT-LAMP), localized surface plasmon resonance (LSPR) biosensors, nucleic acid sequence-based amplification (NASBA), and recombinase polymerase amplification (RPA). Additionally, we discuss the limitations of currently available diagnostic methods, the potential of newly developed sensing technologies, and also provide insight into future areas of research.
Thermodynamic and Economic Analysis Between Organic Rankine Cycle and Kalina Cycle for Waste Heat Recovery From Steam-Assisted Gravity Drainage Process in Oilfield
Authors: Zhang Li , Pan Zhen , Zhang Zhien , Shang Liyan , Wen Jiangbo , Chen Shujun
Published: August 2018

A thermodynamic and economic comparative analysis are presented for waste heat recovery (WHR) from the heavy oil production with steam-assisted gravity drainage (SAGD) process employing organic Rankine cycle (ORC) and Kalina cycle (KC). The liquefied natural gas (LNG) cold energy is employed as the cold source. Thus, a combined cooling heating and power system is proposed. The effect of key parameters on thermodynamic performance is investigated. The results showed that increasing the turbine inlet temperature (TIT), ORC is more appropriate for WHR in SAGD process than KC, but KC provides better energy use and exergy efficiency, while the reverse situation occurs when the evaporation pressure is increased. The compression ratio has little effect on the cold exergy recovery efficiency of the refrigeration cycles. In addition, the total exergy destruction and the total WHR efficiency in the combined SAGD/KC are slightly higher than these in the combined SAGD/ORC. Moreover, for the TIT below 180 °C and the evaporation pressure above 6 MPa, the SAGD/KC can obtain more energy return on investment (EROI) than SAGD/ORC. The results obtained through economic analysis show that the use of the SAGD/ORC is more economical. Through the thermos-economic comparison of the two combined systems, it helps to choose different combined cycles according to the different actual operation, which can facilitate the future engineering applications.
Optimal Placement and Sizing of Photovoltaic Based Distributed Generation Considering Costs of Operation Planning of Monocrystalline and Thin-Film Technologies
Authors: Abdul Kadir Aida Fazliana , Khatib Tamer , Lii Loo Soon , Hassan Elia Erwani
Published: August 2018

Distributed generation (DG) technology has been growing rapidly in industries as this technology can increase the overall efficiency to the power systems. Improper placement and sizing can lead to power losses and interrupt the voltage profile of distribution systems. Studies have been done to solve the DG placement and sizing problem considering several factors, and one of the common factor is minimizing the power losses. However, it is not adequate by only considering the power losses, whereas, the costs of the generation, investment, maintenance, and losses of the distribution system must be taken in consideration. In this research, DG chosen to study is photovoltaic (PV) type which is monocrystalline and thin-film. Costs of operation planning with respect to the power losses is considered which include the costs of investment, maintenance, power loss, and generation that are determined for optimal placement and sizing of DG. The proposed method improved gravitational search algorithm (IGSA) is used in the matlab environment to find the optimal placement and sizing of DG and is tested with the IEEE 34-bus system. The performance of IGSA is then compared with gravitational search algorithm (GSA) and particle swarm optimization (PSO) to find out which algorithm gives the best fitness value and convergence rate. The purpose of this research is to identify the operation planning cost based on the optimization results and improves the optimal placement and sizing of DG in future, to provide maximum economical, technical, environmental benefits, and increase the overall efficiency to the power system.
Vibration-Based Condition Monitoring of Wind Turbine Gearboxes Based on Cyclostationary Analysis
Authors: Mauricio Alexandre , Qi Junyu , Gryllias Konstantinos
Published: August 2018

Wind industry experiences a tremendous growth during the last few decades. As of the end of 2016, the worldwide total installed electricity generation capacity from wind power amounted to 486,790 MW, presenting an increase of 12.5% compared to the previous year. Nowadays wind turbine manufacturers tend to adopt new business models proposing total health monitoring services and solutions, using regular inspections or even embedding sensors and health monitoring systems within each unit. Regularly planned or permanent monitoring ensures a continuous power generation and reduces maintenance costs, prompting specific actions when necessary. The core of wind turbine drivetrain is usually a complicated planetary gearbox. One of the main gearbox components which are commonly responsible for the machinery breakdowns are rolling element bearings. The failure signs of an early bearing damage are usually weak compared to other sources of excitation (e.g., gears). Focusing toward the accurate and early bearing fault detection, a plethora of signal processing methods have been proposed including spectral analysis, synchronous averaging and enveloping. Envelope analysis is based on the extraction of the envelope of the signal, after filtering around a frequency band excited by impacts due to the bearing faults. Kurtogram has been proposed and widely used as an automatic methodology for the selection of the filtering band, being on the other hand sensible in outliers. Recently, an emerging interest has been focused on modeling rotating machinery signals as cyclostationary, which is a particular class of nonstationary stochastic processes. Cyclic spectral correlation and cyclic spectral coherence (CSC) have been presented as powerful tools for condition monitoring of rolling element bearings, exploiting their cyclostationary behavior. In this work, a new diagnostic tool is introduced based on the integration of the cyclic spectral coherence (CSC) along a frequency band that contains the diagnostic information. A special procedure is proposed in order to automatically select the filtering band, maximizing the corresponding fault indicators. The effectiveness of the methodology is validated using the National Renewable Energy Laboratory (NREL) wind turbine gearbox vibration condition monitoring benchmarking dataset which includes various faults with different levels of diagnostic complexity.
The Viscosity of Polyalphaolefins Mixtures at High Pressure and Stress
Authors: Bair Scott , Flores-Torres Samuel
Published: August 2018

Understanding the pressure and shear dependence of viscosity is essential to an understanding of the mechanisms of film forming and friction in concentrated contacts. The blending of different molecular mass polyalphaolefins (PAOs) may permit the formulator to arrive at a desired combination of film thickness and friction. The viscosities of PAO base oils and their blends were measured versus temperature, pressure, and shear stress to 1 GPa in pressure. The Grunberg–Nissan mixing rule, with effective mole fractions, provides an excellent mixing rule for the temperature and pressure-dependent low-shear viscosity. This work provides the first look at a possible mixing rule for the non-Newtonian response of mixtures of base oils.
The Investigation of Geometric Parameters on the Injection Characteristic of the High Pressure Common-Rail Injector
Authors: Wang Ling , Li Guo-Xiu , Xu Chun-Long , Xi Xing , Wu Xiao-Jun , Sun Shu-Ping
Published: August 2018

According the actual structure and working principle of a fuel injector to build a model of the common-rail injector, including the control valve, the solenoid valve, and the needle valve of the injector. The model includes the leakage model for the control piston and needle valve that takes into account increasing leakage at high pressure. The performance of the fuel injector is investigated using a one-dimensional numerical model. Analyzing the effect of the system and structure parameters including common-rail pressure, injection pulse width, inlet and outlet hole diameter, and the injection nozzle on the injection characteristics of the fuel injector. Results show that the geometric parameter is the main property affecting the flow characteristic of the injector, which includes the flow rate of inlet and outlet hole, pressure waves in the control chamber and injection rate. The common-rail pressure, injection pulse width and the geometric parameters mainly affect the injection performance, such as the injection rate and injected volume. The investigation result can provide some useful information to improve the injection characteristic in follow-up studies.
T63 Turbine Response to Rotating Detonation Combustor Exhaust Flow
Authors: Naples Andrew , Hoke John , Battelle Ryan , Schauer Fred
Published: August 2018

This paper describes testing an axial turbine response when driven by a rotating detonation combustor (RDC). A T63 (C20-250) gas turbine is modified by replacing the combustor with a RDC. The stator vanes of the T63 are heavily instrumented for the measurement of flow enthalpy and pressure. The engine is run at multiple power levels with the stock combustor using JetA and hydrogen fuel. The engine is then modified to have an open loop configuration and is run with both the RDC and the stock combustor hardware with hydrogen fuel. Temperature pattern factor, flow unsteadiness, and turbine component efficiency are measured for all setups. High-speed pressure transducers show substantially higher unsteadiness generated by the RDC than the conventional combustor. RDC turbine component efficiencies are compared to the conventional combustor. Results suggest that RDC unsteadiness does not significantly impact turbine efficiency.
Wafer-scale fabrication of CMOS-compatible, high aspect ratio encapsulated nanochannels
Authors: Smith Melissa Alyson , Weaver Isaac , Rothschild Mordechai
Published: August 2018

Nanochannels are key structures in nanofluidics for a variety of different applications. However, typical nanochannel fabrication methods are ill-suited for full integration with other microfabricated components or devices. Here, nanochannels with an aspect ratio (length to cross-sectional dimension) of greater than 400 000 were demonstrated—where the width (35–40 nm) and height (140–150 nm) of the channels are sufficiently small to elongate macromolecules—at channel lengths on the order of millimeters. These channels were fabricated with a CMOS-compatible toolset, allowing for the batch fabrication of a multitude of channels and with the further potential of full integration with solid-state electronic and photonic devices on the same wafer. Finally, the versatility of the nanochannel fabrication platform was demonstrated by loading the channels with six different liquids, and it was verified that the fluid flow dynamics for each liquid can be well estimated with Washburn's equation.
Prediction of sound absorption based on specific airflow resistance and air permeability of textiles
Authors: Tang Xiaoning , Jeong Cheol-Ho , Yan Xiong
Published: August 2018

Both specific airflow resistance and air permeability can be used as a parameter to estimate the sound absorption of textiles. The measurement of specific airflow resistance is specified in ISO 9053 (Int. Standards Org., 1991), but it is known to be inaccurate for low specific airflow resistance. This paper compares the measured specific airflow resistance according to ISO 9053 and those calculated from air permeability according to ISO 9237 (Int. Standards Org., 1995). The sound absorption coefficients predicted by Pieren's model [R. Pieren, Textile Res. J. 82(9), 864–874 (2012)] are compared with measurements by the impedance tube method, which concludes that those predicted from the air permeability are more accurate than those from the measured specific airflow resistance for textiles.