bluuebunny/crossref_metadata_2025 huggingface dataset:
Leakage and Force Coefficients of a Grooved Wet (Bubbly Liquid) Seal for Multiphase Pumps and Comparisons With Prior Test Results for a Three Wave Seal
Authors: Lu Xueliang , San Andrés Luis , Wu Tingcheng
Published: September 2019

In the subsea oil and gas industry, multiphase pumps and wet gas compressors are engineered choices saving transportation and separation facility costs. In these machines, seals handling multiple phase components must be able to operate without affecting the system efficiency and its dynamic stability. This paper, extending prior work conducted with uniform clearance and wavy surface annular seals, presents measurements of leakage and dynamic force coefficients in a grooved seal whose dimensions are scaled from an impeller wear ring seal in a boiler feed pump. The 14-grooves seal has diameter D = 127 mm, length L = 0.34 D, and clearance c = 0.211 mm; each groove has shallow depth dg ∼2.6 c and length Lg ∼ 3.4% L. At a shaft speed of 3.5 krpm (surface speed = 23.3 m/s), a mixture of air in ISO VG 10 oil with inlet gas volume fraction (GVF) ranging from 0 (just oil) to 0.7 (mostly air) lubricates the seal. The pressure ratio (inlet/exit) is 2.9. The flow is laminar since the liquid is viscous and the pressure drop is low. The measured mixture mass flow decreases continuously with an increase in inlet GVF. The seal stiffnesses (direct K and cross coupled k), added mass (M), and direct damping (C) coefficients are constant when the supplied mixture is low in gas content, GVF ≤ 0.1. As the gas content increases, 0.2 ≤  GVF ≤ 0.5, the seal direct dynamic stiffness becomes nil with an increase in excitation frequency, whereas k and C reduce steadily with GVF. In general, for GVF ≤ 0.5, the direct damping is invariant with frequency; variations appearing for GVF = 0.7. Compared against a three wave annular seal, the grooved seal offers much lower force coefficients, in particular the viscous damping. Thus, for laminar flow operation (heavy oil) with a low pressure drop as in a wear ring seal, a three wave seal is recommended as it also offers a significant centering stiffness.
Rotated G-Shaped Insertion to Suppress Natural Convection Inside a Square Enclosure That Has Conductive Walls
Authors: Alhazmy Majed M.
Published: September 2019

This paper presents the results of a numerical study for using a simple insertion to reduce the heat transfer through an air-filled square cavity when subjected to a temperature gradient. The insertion is a rectangular sheet folded in a special way to produce the shape of a rotated letter G. The insertion is thermally conductive, and in perfect contact with the walls of the cavity. The cavity has thick conductive walls. The two outer vertical sides of the cavity are isothermal, and the two horizontal sides are adiabatic. The solution of continuity, momentum, and energy equations for this system yields the isotherms, streamlines, and heat flux transported across the cavity. The insertion suppresses the convection currents inside the cavity and hence reduces the heat transfer rate across them. The analysis shows the effect of the insertion dimensions and thermal properties on the heat transfer rate through the cavity. This paper also presents the results of using this insertion inside the holes of an ordinary building brick. The insertion is an easy tool to manufacture and a simple device to use for reducing the heat transfer through the blocks. The G insertion reduces the heat flux by 27–42%.
Grasp and Orientation Control of an Object by Two Euler–Bernoulli Arms With Rolling Constraints
Authors: Endo Takahiro , Shiratani Nobuhiro , Yamaguchi Kaiyo , Matsuno Fumitoshi
Published: September 2019

This paper focuses on grasping and manipulation of an object by two one-link flexible arms. By taking rolling constraints between the arm tip and the grasped object, the arms have the potential to grasp and manipulate an object at the same time. To realize grasping and manipulation by two flexible arms, a boundary controller is derived from a Lyapunov functional related to the total energy of a dynamic model described by a hybrid partial differential equation-ordinary differential equation (PDE-ODE) model. The derived controller consists of the bending moment at the root of the arm, the rotational angle, and the angular velocity of the motor. In particular, the controller does not need the feedback of the information of the grasped object, and thus, it is easy to implement the controller. Further, it is shown that the derived controller realizes stable grasping and orientation control of the object as well as vibration control of the arms. Finally, experiments and numerical simulations are conducted to investigate the validity of the derived boundary controller.
A Nonlinear Integral Sliding Surface to Improve the Transient Response of a Force-Controlled Pneumatic Actuator With Long Transmission Lines
Authors: Butt Khurram , Sepehri Nariman
Published: September 2019

A force-controlled pneumatic actuator with long connecting tubes is a well-accepted solution to develop magnetic resonance imaging (MRI)-compatible force control applications. Such an actuator represents an uncertain, second-order, nonlinear system with input delay. The integral sliding mode control, because of guaranteed robustness against matched uncertainties throughout the system response, provides a favorable option to design a robust controller for the actuator. However, if the controller is based on a linear integral sliding surface (LISS), the response of the actuator overshoots, especially when there are large initial errors. Minimizing overshoot results in a smaller controller bandwidth and a slower system response. This paper presents a novel nonlinear integral sliding surface (NLISS) for a sliding mode controller to improve the transient response of the actuator. The proposed surface is a LISS augmented by a nonlinear function of tracking error and does not have a reaching phase when there are initial errors and even multiple steps in the desired trajectory. The surface enables the integral sliding mode controller to offer variable damping, which changes from low to high as the transient error approaches small values and vice versa. Simulation studies and experimental results show that the controller based on the proposed sliding surface successfully eliminates the overshoot without compromising the controller bandwidth, rise, and settling times. For performance evaluation, the controller parameters are tuned using the globalized and bounded Nelder–Mead (GBNM) algorithm with deterministic restarts. The study also establishes the asymptotic stability of the controller based on the proposed sliding surface using Lyapunov's stability criterion.
On the Connection Between Geometry and Statically Determined Membrane Stresses in the Human Cornea
Authors: Angelillo M. , Montanino A. , Pandolfi A.
Published: September 2019

Under the action of the intraocular pressure (IOP), the human cornea is stressed and deforms acquiring a quasi-spherical configuration. If the stressed configuration is known, and the cornea is regarded as a membrane, disregarding flexural behaviors with an equilibrium analysis only is possible to estimate the distribution of the average stress across the thickness. In the cornea, the action of the intraocular pressure is supported by collagen fibrils, immersed into an elastin-proteoglycan matrix, and organized in a very precise architecture to provide the necessary confinement and transparency to the light. With the goal of understanding the static consequences of shape modifications due to pathological dilatation (ectasia), we present a simplified stress analysis of the human cornea modeled as a membrane. A numerical investigation over 40 patient-specific corneas (20 normal and 20 ectatic) is carried out to establish a relationship between the physiological geometry and the distribution of the membrane stresses, and to assess the possibility to obtain information on the stress state based on topographic images only. Comparative analyses reveal that, with respect to normal corneas, in ectatic corneas the pattern of the principal stress lines is modified markedly showing a deviation from the hypothetical dominant orientation of the collagen fibrils. The rotation of the principal stress with respect to the fibril orientation can be thought as responsible of the transmission of a large amount of shear stresses onto the elastin-proteoglycan matrix. The anomalous loading of the matrix could be correlated to the evolution of time-dependent shape modifications leading to ectasia.
Enhanced Accident Tolerance of Thoria-Based Nuclear Fuels
Authors: Szpunar B. , Szpunar J. A.
Published: September 2019

Many factors need to be investigated before alternative nuclear fuel can be adapted for service in the harsh environment of a nuclear reactor. Urania, used conventionally as a nuclear fuel, has a low thermal conductivity, which degrades with increasing stoichiometric deviation. Thoria-based fuel has been considered as an alternative fuel, since it does not oxidize and has a high melting point and higher thermal conductivity. Simulations have shown that the fuel melting observed in urania fuel rods during an accident with steam ingress should not be observed (or will be delayed) in thoria as its thermal conductivity remains high enough to dissipate excessive heat in the center of the fuel pellets. The thermal gradient also remains low and therefore thermal stress is reduced, which should improve the longevity of the fuel. Thoria also has some other desirable properties as our calculations predict a significantly higher temperature of oxygen lattice premelting than urania. Furthermore, we found that the diffusion of fission gas, e.g., helium, is strongly affected by oxygen diffusion and therefore is slower in thoria for the temperatures where the oxygen lattice premelts in urania, but not in thoria.
Improving Engagement With Biomechanics: Student Perspectives and a Professional Development Initiative
Authors: Shultz Sarah P. , Millar Sarah-Kate , Fink Philip W. , Hébert-Losier Kim , Handsfield Geoffrey , Sheerin Kelly , Wells Denny , Clarke Jenny
Published: September 2019

Student engagement is an essential aspect of educational environments, and this is especially true for Science, Technology, Engineering, and Mathematics (STEM) disciplines, where student engagement declines in middle and high school years. Techniques for bolstering student engagement, such as hands-on learning, may be especially effective in the field of biomechanics since this discipline is rooted in STEM and has fundamental applications to everyday movement. To this end, this paper describes (1) the perceptions of student teachers in their first year of tertiary (undergraduate) education regarding the biomechanics content from their secondary (high school) education, and (2) a professional development initiative, in the form of a discipline-specific teacher training workshop, to enhance biomechanics resources for teachers via peer networking. The perception of student teachers in their first year of tertiary education in teaching indicated a positive relationship between perception of secondary school teaching quality and self-confidence with specific biomechanical concepts. Open responses focused on the need to cover concepts thoroughly, using practical activities where possible, and taking time to ensure understanding before progressing to more advanced concepts. The teacher training workshop provided secondary school Physical Education teachers with an opportunity to network nationally with other teachers across New Zealand, and internationally with university-based biomechanics researchers. Peer focus groups helped to design and refine sets of experiential learning activities that could be easily implemented in the classroom.
An Instrumented High-Speed Rotor With Embedded Telemetry for the Continuous Spatial Pressure Profile Measurement in Gas Lubricated Bearings: A Proof of Concept
Authors: Shalash Karim , Schiffmann Jürg
Published: September 2019

Pressure is the constitutive quantity governing the flow field in gas lubricated bearings. Knowledge of the pressure is of principal importance in the fundamental understanding of such bearings as well as for the validation of their models. Pressure measurements can be done from the bearing side using pressure taps, yet, several details will not be captured. In order to acquire a continuous scan of the pressure field inside the bearing, it is necessary to measure from the rotor side. This paper presents an instrumented measurement high-speed rotor with embedded pressure probes and a wireless telemetry that is capable of the continuous pressure field measurement within the gas film of journal bearings. The rotor was tested on externally pressurized gas journal bearings (EPGJBs) (D = 40 mm and L/D = 1), and pressure profile measurements were acquired up to 37.5 krpm (DN 1.5 M). Measurements at discrete points using pressure taps inside the test bearing were also performed for comparison. The measurements from both sides (bearing and rotor) were in good agreement at quasi-static conditions. At higher operational speeds, it was necessary to perform an in situ system identification and calibration for the embedded pressure probes using the bearing side measurements as a reference. The in situ system identification technique was successful to reconstruct the attenuated pressure signals for a wide range of supply pressures (amplitudes) and rotor speeds (excitation frequencies). The instrumented rotor was proven qualified to perform time-resolved pressure measurements within the gas film of journal bearings up to 37.5 krpm.
Pressure Profile Measurements Within the Gas Film of Journal Foil Bearings Using an Instrumented Rotor With Telemetry
Authors: Shalash Karim , Schiffmann Jürg
Published: September 2019

Foil bearings are strong candidates to support oil-free turbomachinery. Although foil bearings are a widely used technology, models describing their behavior are not validated using the film pressure, which is the fundamental variable of any fluid film bearing. This paper presents pressure profiles measured within the gas film of a journal foil bearing. The pressure is measured using an instrumented rotor with embedded pressure probes and wireless telemetry. The measurements yield the simultaneous circumferential pressure profiles at two axial positions inside the bearing. Proximity probes on the bearing allowed the measurement of the corresponding rotor orbits. The bearing under investigation is a bump-type compliant journal bearing, with a nominal diameter of 40 mm, an L/D = 1, and was tested up to 37.5 krpm. Load-displacement and break-away tests were performed on the test bearing in order to identify bearing parameters necessary for reproducibility. The pressure profiles are compared to a frequency domain foil bearing model. This paper is a step toward further fundamental understanding of the foil bearing behavior and the validation of the rich modeling literature.
Paramagnon drag in high thermoelectric figure of merit Li-doped MnTe
Authors: Zheng Y. , Lu T. , Polash Md M. H. , Rasoulianboroujeni M. , Liu N. , Manley M. E. , Deng Y. , Sun P. J. , Chen X. L. , Hermann R. P. , Vashaee D. , Heremans J. P. , Zhao H.
Published: September 2019

Neutrons spot magnetic fluctuations that propel charges in a novel class of paramagnetic thermoelectrics.
Flexible graphene photodetectors for wearable fitness monitoring
Authors: Polat Emre O. , Mercier Gabriel , Nikitskiy Ivan , Puma Eric , Galan Teresa , Gupta Shuchi , Montagut Marc , Piqueras Juan José , Bouwens Maryse , Durduran Turgut , Konstantatos Gerasimos , Goossens Stijn , Koppens Frank
Published: September 2019

Flexible and transparent graphene photodetector technology allows non-invasive monitoring of vital signs.
3D-printed automation for optimized PET radiochemistry
Authors: Amor-Coarasa Alejandro , Kelly James M. , Babich John W.
Published: September 2019

3D printing, robotics, and a series of digital sequences combine for the automated production of radioactive pharmaceuticals.
Inhibition of IL-2 responsiveness by IL-6 is required for the generation of GC-T
FH
cells
Authors: Papillion Amber , Powell Michael D. , Chisolm Danielle A. , Bachus Holly , Fuller Michael J. , Weinmann Amy S. , Villarino Alejandro , O’Shea John J. , León Beatriz , Oestreich Kenneth J. , Ballesteros-Tato André
Published: September 2019

IL-6–mediated inhibition of CD122 allows T
FH
cells to receive TCR signaling without initiating an inhibitory TCR/IL-2 loop (see the related Focus by
Zhou and Yu
)..
Germinal center T
FH
cells: T(w)o be or not t(w)o be, IL-6 is the answer
Authors: Zhou Pengcheng , Liang Kaili , Yu Di
Published: September 2019

IL-6 inhibits the expression of IL-2Rβ (CD122) in germinal center T
FH
cells to maintain IL-2 hyporesponsiveness (see the related Research Article by

Papillion
et al
.

).
A Thrice-Weekly Ertapenem Regimen Is Practical for Hemodialysis Patients
Authors: Ueng Yune-Fang , Wang Hong-Jaan , Wu Shiao-Chi , Ng Yee-Yung
Published: September 2019

A change of ertapenem dosage from 500 mg daily to thrice weekly, after each hemodialysis session, can maintain the plasma concentration above 2 mg/liter and be practical for hemodialysis patients.
Rare case of triple mutant (KRAS + NRAS + BRAF) metastatic colon adenocarcinoma
Authors: Vittal Anusha , Sharma Disha , Samanta Ipsita , Kasi Anup
Published: September 2019

KRAS is detected in 30%–50% of colorectal cancer (CRC) and BRAF mutations are found in 10% of CRC. A 62-year-old man with the long-standing smoking history presented to the emergency department with abdominal pain, weight loss and constipation. CT scan of abdomen/pelvis showed obstructive mass which was found to be colon adenocarcinoma which on further molecular analysis tested positive for KRAS, NRAS and BRAF mutations. His tumour progressed despite chemotherapy and surgery and he died within a year of diagnosis. Concomitant KRAS, NRAS and BRAF mutations are rare enough to be considered mutually exclusive but coexistent mutations appear to be a distinct molecular and clinical subset which needs new and effective treatment strategies in a setting of dismal prognosis.
Mutation spectrum of the bestrophin-1 gene in a large Chinese cohort with bestrophinopathy
Authors: Gao Feng-Juan , Qi Yu-He , Hu Fang-Yuan , Wang Dan-Dan , Xu Ping , Guo Jing-Li , Li Jian-Kang , Zhang Yong-Jin , Li Wei , Chen Fang , Xu Ge-Zhi , Liu Wei , Chang Qing , Wu Ji-Hong
Published: September 2019

Background

Bestrophin-1 (BEST1) gene is associated with a wide range of ocular phenotypes, collectively termed as bestrophinopathy. The aim of the current study was to identify the mutation spectrum ofBEST1in a large cohort of Chinese patients with bestrophinopathy.

Methods

Patients clinically suspected of bestrophinopathy were screened using multigene panel testing. AllBEST1variants were confirmed by Sanger sequencing, and validated in the families.

Findings

A total of 92 patients (Best vitelliform macular dystrophy (BVMD)=77; autosomal recessive bestrophinopathy (ARB)=15) from 58 unrelated families of Chinese origin and their available family members (n=65) were recruited. Overall, 39 distinct disease-causingBEST1variants were identified, including 13 novel variants, and two reported variants but novel for ARB. Of them, 14 were associated with ARB, 23 with BVMD and two (c.604C>T and c.898G>A) with both BVMD and ARB. Most mutations associated with BVMD were missense (97.78%), while ARB was associated with more complex mutations, including missense (88.46%), splicing effect (3.85%), and frameshifts (15.38%).BEST1hotspots were c.898G>A and c.584C>T among BVMD and ARB patients, respectively. Hot regions were located in exons 8, 2 and 6 in BVMD patients, and in exons 5 and 7 in ARB patients. The overall penetrance ofBEST1in our cohort was 71.30%, no de novo mutations were identified.

Conclusion

This is the largest study to date that provides major population-based data of theBEST1mutation spectrum in China. Our results can serve as a well-founded reference for genetic counselling for patients with bestrophinopathy of Chinese origin.
Disproportion of lamellar capillary non-perfusion in proliferative diabetic retinopathy on optical coherence tomography angiography
Authors: Uchitomi Daiki , Murakami Tomoaki , Dodo Yoko , Yasukura Shota , Morino Kazuya , Uji Akihito , Yoshitake Tatsuya , Fujimoto Masahiro , Tsujikawa Akitaka
Published: September 2019

Purpose

To characterise the non-perfused areas (NPAs) in the superficial and deep capillary layers (sNPAs and dNPAs, respectively) in the posterior pole in proliferative diabetic retinopathy (PDR) on wide-field optical coherence tomography angiography (OCTA) images.

Methods

We retrospectively reviewed 104 eyes of 70 patients with PDR from whom wide-field swept source OCTA images were acquired. sNPAs and dNPAs were manually measured in each quadrant of the inner (1–3 mm diameter), intermediate (3–6 mm), and outer (6–10 mm) rings centred on the fovea. Two qualitative findings, that is,segmented NPAsandperiarteriolar NPAs, were also compared.

Results

The dNPAs were greater than the sNPAs (p<0.001) in each subfield. The outer ring had higher rates of deep NPAs than did the intermediate ring in the superior, inferior and temporal quadrants (p=0.010, p=0.004 and p<0.001, respectively), whereas no differences were detected in the nasal quadrant (p=1.000). Similarly, sNPA rates were higher in the outer ring than in the intermediate ring in the inferior and temporal subfields (p=0.003 and p<0.001, respectively). In 45 eyes with extensive NPAs, there were modest correlations between the dNPAs in the nasal and temporal quadrants in the intermediate (ρ=0.341, p=0.026) and outer (ρ=0324, p=0.032) rings, whereas sNPAs exhibited no associations.Segmented NPAswere delineated more frequently in the superficial layer than in the deep layer (p<0.001).Periarteriolar NPAswere more frequent in the deep layer (p<0.001).

Conclusions

Three-dimensional assessment of wide-field OCTA promotes a better understanding of the enigmatic disproportion of lamellar NPAs in the posterior pole in PDR.
Reducing prolonged chemoradiation treatment times for cervical cancer
Authors: Vitzthum Lucas , Yuan Jianling , Jones Daniel , Boldt Anne , Dusenbery Kathryn
Published: September 2019

Prolonged total treatment times (TTTs) beyond 56 days are associated with worse outcomes for cervical cancer treated with radiation therapy. We reviewed treatment times in a cohort of 24 consecutive patients treated with definitive chemoradiation (CRT) at our institution and found that only 14 patients (58.3%) completed treatment in less than or equal to 56 days. The primary objectives of this institutional quality improvement initiative were to identify sources for delays in treatment completion and to implement effective measures in an effort to minimise prolonged TTT. Pareto plot and process mapping were used to identify and resolve root causes of prolonged treatment. The Plan-Do-Study-Act method was then implemented to reduce treatment duration. Post-intervention treatment times were prospectively evaluated in 81 subsequent patients treated with definitive CRT. Process mapping identified inefficiencies with scheduling, staggered treatments and inadequate patient and staff education. Institutional changes were implemented, heavily utilising oncology nurses’ skill set in staff re-education and care coordination. Our workflow was redesigned to reduce/eliminate treatment delays. These interventions led to a significant improvement in the percentage of patients meeting the goal TTT compared with the pre-intervention cohort (85.2% vs 58.3%, p<0.01), and results were sustainable in additional 47 patients prospectively followed subsequently, potentially making a positive impact on their treatment outcomes.
Quality of life after in-hospital cardiopulmonary resuscitation for patients over the age of 80 years
Authors: Burden Eleanor , Pollock Lucy , Paget Camilla
Published: September 2019

Objectives

Success of in-hospital resuscitation decreases with age; however, national data show that 11.3% of patients over 80 years survive to discharge. There are few published qualitative data about the quality of life for these patients postsuccessful resuscitation. We aimed to investigate postresuscitation quality of life in patients over the age of 80 through a series of case studies.

Methods

All patients over the age of 80 years, who received cardiopulmonary resuscitation (CPR) at our district general hospital in 2015–2016, were included. Success of resuscitation, survival at day 1 and to discharge were recorded. For patients who survived to 1 day and beyond, case reports were written to create individual patient stories.

Results

47 patients over the age of 80 years received CPR at Musgrove Park Hospital over a 2-year period. Five (10.6%) survived to discharge. Of those surviving to discharge, two had substantial functional decline, requiring discharge to nursing homes having previously been independent. Of the five families/patients who commented on their experience, only one expressed a positive view. When discussed, the majority of patients/families opted for a Do Not Attempt CPR.

Conclusion

Our results have shown that there is a risk of substantial functional decline associated with successful CPR in those patients over the age of 80 years. The majority of patients and relatives contacted after successful resuscitation expressed a negative view of the experience. Our study highlights the importance of having early informed discussions with patients and families about CPR in order to avoid detrimental outcomes and ensure patient wishes are correctly represented.
Preserving fertility: using cyclophosphamide and other cytotoxics in young people
Authors: Ledingham David , Plant Michael , Mustafa Fayez , Patil Bhimanagouda
Published: September 2019

Cytotoxic agents such as cyclophosphamide are infrequently used in neurological practice. When they are, it is commonly in critically ill patients or in those with refractory inflammatory disorders. Cyclophosphamide in particular has a well-recognised negative impact on both female and male long-term fertility. This article summarises the data with regards the impact of cytotoxics on long-term fertility and describes the current options to preserve fertility in these patients. We hope this will provide neurologists with a useful aid for counselling patients for whom they are considering these treatments.
Ambient heat and hospitalisation for COPD in Brazil: a nationwide case-crossover study
Authors: Zhao Qi , Li Shanshan , Coelho Micheline de Sousa Zanotti Staglior , Saldiva Paulo Hilário Nascimento , Xu Rongbin , Huxley Rachel R , Abramson Michael J , Guo Yuming
Published: September 2019

Background

Heat exposure has been related to increased morbidity and mortality for several health outcomes. There is little evidence whether this is also true for COPD. This study quantified the relationship between ambient heat and hospitalisation for COPD in the Brazilian population.

Methods

Data on hospitalisations for COPD and weather conditions were collected from 1642 cities during the 2000–2015 hot seasons. A time-stratified, case-crossover design was used for city-specific analyses, which were then pooled at the regional and national levels using random-effect meta-analyses. Stratified analyses were performed by sex, age group and early/late hot season. Annual change in the association was examined using a random-effect meta-regression model.

Results

The OR of hospitalisation was 1.05 (95% CI 1.04 to 1.06) for every 5℃ increase in daily mean temperature at the national level, with the effect estimate stronger in the late hot season compared with the early hot season. The effect was similar in women and in men but was greatest for those aged ≥75 years. The association was stronger in the central west and southeast regions and minimal in the northeast. Assuming a causal relationship, 7.2% of admissions were attributable to heat exposure. There was no significant temporal decline in the impact of ambient heat over the 16-year study period.

Conclusion

In Brazil, exposure to ambient heat was positively associated with hospitalisation for COPD, particularly during the late hot season. These data add to the growing evidence base implicating global warming as being an important contributor to the future healthcare burden.
Spurious finite-size instabilities with Gogny-type interactions
Authors: Martini M. , De Pace A. , Bennaceur K.
Published: September 2019

Recently, a new parameterization of the Gogny interaction suitable for astrophysical applications, named D1M*, has been presented. We investigate the possible existence of spurious finite-size instabilities of this new Gogny force by repeating a study that we have already performed for the most commonly used parameterizations (D1, D1S, D1N, D1M) of the Gogny force. This study is based on a fully antisymmetrized random phase approximation (RPA) calculation of the nuclear matter response functions employing the continued fraction technique. It turns out that this new Gogny interaction is affected by spurious finite-size instabilities in the scalar isovector channel; hence, unphysical results are expected in the calculation of properties of nuclei, like neutron and proton densities, if this D1M* force is used. The conclusions from this study are then, for the first time, tested against mean-field calculations in a coordinate representation for several nuclei. Unphysical results for several nuclei are also obtained with the D1N parameterization of the Gogny force. These observations strongly advocate for the use of the linear response formalism to detect and avoid finite-size instabilities during the fit of the parameters of Gogny interactions as it is already done for some Skyrme forces.
Revisiting the e+e−→ K+K−J/ψ line shape
Authors: Zhang Jielei , Zhu Tengjiao , He Jinjin
Published: September 2019

The cross-section of [Formula: see text] has been measured by BESIII experiment, two enhancements are seen around 4.2 GeV and 4.5 GeV. We try to fit the cross-section with coherent sum of two Breit–Wigner functions, the fit results show [Formula: see text] line shape can be described by [Formula: see text] and a new structure around 4.5 GeV, also can be described by the known charmonium [Formula: see text] and [Formula: see text]. Based on current data, we cannot distinguish which explanation is right. More measurements around 4.2 GeV and 4.5 GeV are desired to improve the understanding of the structures in [Formula: see text].
Symmetry reduction, exact solutions and conservation laws of the Bogoyavlenskii equation
Authors: Wang Zhenli , Li Chuan Zhong , Zhang Lihua
Published: September 2019

In this paper, by applying the direct symmetry method, we obtain the symmetry reductions, group invariant solutions and some new exact solutions of the Bogoyavlenskii equation, which include hyperbolic function solutions, trigonometric function solutions and power series solutions. We also give the conservation laws of the Bogoyavlenskii equation.
1-Bromo-1,2-dicyanoethylene: A dicyanoacetylene synthon useful in tetraazaporphyrin synthesis
Authors: Fitzgerald Jeffrey P. , Korenak John P. , Steinaker Delano A. , Swogger Logan M. , Lois Jessica A.
Published: September 2019

Dicyanoacetylene, a highly reactive dienophile, readily reacts to form substituted maleonitriles which serve as precursors to soluble tetraazaporphyrins. Unfortunately, dicyanoacetylene is difficult to synthesize in large quantities. We report here a new dicyanoacetylene synthon, 1-bromo-1,2-dicyanoethylene, which is easily made in high yield by reaction of elemental bromine with fumaronitrile and easily purified by vacuum distillation. The resulting 5:1 mixture of geometric isomers reacts with dienes via a Diels–Alder reaction followed by elimination of HBr to give substituted maleonitriles. We demonstrate the utility of these reactions by reporting the synthesis of a novel, soluble tetraazaporphyrin bearing four 1,4-fused cyclohexyl groups on the macrocycle periphery.
An experimental and numerical investigation on the hydromechanical behaviour of carbonate fault zones upon reactivation: the impact of carbonate mud sealing layers and overall research outcomes
Authors: Nogueira Kiewiet M. , Lima C. , Giwelli A. , Delle Piane C. , Lemiale V. , Esteban L. , Falcao F. , Clennell M. B. , Dautriat J. , Kiewiet L. , Raimon J. , Kager S. , Dewhurst D.
Published: September 2019

To contribute to the understanding of the impacts of fault reactivation induced by reservoir exploitation, we describe the final series of laboratory experiments, numerical simulations and microstructural analysis conducted during the ‘Fault Reactivation in Carbonates’ research project. In the project, the structure and hydromechanical properties of carbonate-hosted fault zones were investigated. For the analyses here reported, faults were artificially generated by direct shearing composite blocks made of layers of reservoir analogue rocks (outcrop travertine or synthetic grainstone) intercalated with one layer of a sealing analogue rock (synthetic carbonate mudstone). Post-direct shearing, cylindrical plugs containing the fault zone and parts of intact rock were cored out from the blocks and tested in a triaxial test rig, simulating fault reactivation. Varied stress paths and pore-pressure conditions representative of fluid depletion and injection were considered. In parallel, two-dimensional mechanical models representative of the direct shear experiments were developed using smoothed particle hydrodynamics (SPH). We observed a continuous reduction in fault transmissibility during direct shearing, followed by a permeability reduction of 50–80% with increasing mean effective stress in the subsequent fault reactivation tests. Experimental fault zone geometries produced during direct shear were broadly reproduced by the two-dimensional modelling approach. We also detected that the inclusion of the carbonate mud sealing rock into the fault zone caused greater compaction of the fault materials when compared to experiments conducted without carbonate mud layers. We conclude that with fault displacement, increasing incorporation of carbonate mud sealing material into the fault zone and the concomitant development of gouge results in the continuous reduction of fault transmissibility/permeability. This occurs in the two very different limestone host-rock types and for all the stress configurations investigated. Discussions on these results and also on the outcomes of the research project as a whole are presented in the paper.
Local Learning Approaches for Finding Effects of a Specified Cause and Their Causal Paths
Authors: Liu Yue , Cai Zheng , Liu Chunchen , Geng Zhi
Published: September 2019

Causal networks are used to describe and to discover causal relationships among variables and data generating mechanisms. There have been many approaches for learning a global causal network of all observed variables. In many applications, we may be interested in finding what are the effects of a specified cause variable and what are the causal paths from the cause variable to its effects. Instead of learning a global causal network, we propose several local learning approaches for finding all effects (or descendants) of the specified cause variable and the causal paths from the cause variable to some effect variable of interest. We discuss the identifiability of the effects and the causal paths from observed data and prior knowledge. For the case that the causal paths are not identifiable, our approaches try to find a path set that contains the causal paths of interest.
A Survey on Food Computing
Authors: Min Weiqing , Jiang Shuqiang , Liu Linhu , Rui Yong , Jain Ramesh
Published: September 2019

Food is essential for human life and it is fundamental to the human experience. Food-related study may support multifarious applications and services, such as guiding human behavior, improving human health, and understanding the culinary culture. With the rapid development of social networks, mobile networks, and Internet of Things (IoT), people commonly upload, share, and record food images, recipes, cooking videos, and food diaries, leading to large-scale food data. Large-scale food data offers rich knowledge about food and can help tackle many central issues of human society. Therefore, it is time to group several disparate issues related to food computing. Food computing acquires and analyzes heterogenous food data from different sources for perception, recognition, retrieval, recommendation, and monitoring of food. In food computing, computational approaches are applied to address food-related issues in medicine, biology, gastronomy, and agronomy. Both large-scale food data and recent breakthroughs in computer science are transforming the way we analyze food data. Therefore, a series of works has been conducted in the food area, targeting different food-oriented tasks and applications. However, there are very few systematic reviews that shape this area well and provide a comprehensive and in-depth summary of current efforts or detail open problems in this area. In this article, we formalize food computing and present such a comprehensive overview of various emerging concepts, methods, and tasks. We summarize key challenges and future directions ahead for food computing. This is the first comprehensive survey that targets the study of computing technology for the food area and also offers a collection of research studies and technologies to benefit researchers and practitioners working in different food-related fields.
The Influence of Trust Score on Cooperative Behavior
Authors: Ignat Claudia-Lavinia , Dang Quang-Vinh , Shalin Valerie L.
Published: September 2019

The assessment of trust between users is essential for collaboration. General reputation and ID mechanisms may support users’ trust assessment. However, these mechanisms lack sensitivity to pairwise interactions and specific experience such as betrayal over time. Moreover, they place an interpretation burden that does not scale to dynamic, large-scale systems. While several pairwise trust mechanisms have been proposed, no empirical research examines trust score influence on participant behavior. We study the influence of showing a partner trust score and/or ID on participants’ behavior in a small-group collaborative laboratory experiment based on the trust game. We show that trust score availability has the same effect as an ID to improve cooperation as measured by sending behavior and receiver response. Excellent models based on the trust score predict sender behavior and document participant sensitivity to the provision of partner information. Models based on the trust score for recipient behavior have some predictive ability regarding trustworthiness, but suggest the need for more complex functions relating experience to participant response. We conclude that the parameters of a trust score, including pairwise interactions and betrayal, influence the different roles of participants in the trust game differently, but complement traditional ID and have the advantage of scalability.
Dynamic Malware Analysis in the Modern Era—A State of the Art Survey
Authors: Or-Meir Ori , Nissim Nir , Elovici Yuval , Rokach Lior
Published: September 2019

Although malicious software (malware) has been around since the early days of computers, the sophistication and innovation of malware has increased over the years. In particular, the latest crop of ransomware has drawn attention to the dangers of malicious software, which can cause harm to private users as well as corporations, public services (hospitals and transportation systems), governments, and security institutions. To protect these institutions and the public from malware attacks, malicious activity must be detected as early as possible, preferably before it conducts its harmful acts. However, it is not always easy to know what to look for—especially when dealing with new and unknown malware that has never been seen. Analyzing a suspicious file by static or dynamic analysis methods can provide relevant and valuable information regarding a file's impact on the hosting system and help determine whether the file is malicious or not, based on the method's predefined rules. While various techniques (e.g., code obfuscation, dynamic code loading, encryption, and packing) can be used by malware writers to evade static analysis (including signature-based anti-virus tools), dynamic analysis is robust to these techniques and can provide greater understanding regarding the analyzed file and consequently can lead to better detection capabilities. Although dynamic analysis is more robust than static analysis, existing dynamic analysis tools and techniques are imperfect, and there is no single tool that can cover all aspects of malware behavior. The most recent comprehensive survey performed in this area was published in 2012. Since that time, the computing environment has changed dramatically with new types of malware (ransomware, cryptominers), new analysis methods (volatile memory forensics, side-channel analysis), new computing environments (cloud computing, IoT devices), new machine-learning algorithms, and more. The goal of this survey is to provide a comprehensive and up-to-date overview of existing methods used to dynamically analyze malware, which includes a description of each method, its strengths and weaknesses, and its resilience against malware evasion techniques. In addition, we include an overview of prominent studies presenting the usage of machine-learning methods to enhance dynamic malware analysis capabilities aimed at detection, classification, and categorization.
Orchestrating Big Data Analysis Workflows in the Cloud
Authors: Barika Mutaz , Garg Saurabh , Zomaya Albert Y. , Wang Lizhe , Moorsel Aad Van , Ranjan Rajiv
Published: September 2019

Interest in processing big data has increased rapidly to gain insights that can transform businesses, government policies, and research outcomes. This has led to advancement in communication, programming, and processing technologies, including cloud computing services and technologies such as Hadoop, Spark, and Storm. This trend also affects the needs of analytical applications, which are no longer monolithic but composed of several individual analytical steps running in the form of a workflow. These big data workflows are vastly different in nature from traditional workflows. Researchers are currently facing the challenge of how to orchestrate and manage the execution of such workflows. In this article, we discuss in detail orchestration requirements of these workflows as well as the challenges in achieving these requirements. We also survey current trends and research that supports orchestration of big data workflows and identify open research challenges to guide future developments in this area.
Security Modeling of Autonomous Systems
Authors: Jahan Farha , Sun Weiqing , Niyaz Quamar , Alam Mansoor
Published: September 2019

Autonomous systems will soon be integrating into our lives as home assistants, delivery drones, and driverless cars. The implementation of the level of automation in these systems from being manually controlled to fully autonomous would depend upon the autonomy approach chosen to design these systems. This article reviews the historical evolution of autonomy, its approaches, and the current trends in related fields to build robust autonomous systems. Toward such a goal and with the increased number of cyberattacks, the security of these systems needs special attention from the research community. To gauge the extent to which research has been done in this area, we discuss the cybersecurity of these systems. It is essential to model the system from a security perspective, identify the threats and vulnerabilities, and then model the attacks. A survey in this direction explores the theoretical/analytical system and attack models that have been proposed over the years and identifies the research gap that needs to be addressed by the research community.
A Survey of Tool-supported Assurance Case Assessment Techniques
Authors: Maksimov Mike , Kokaly Sahar , Chechik Marsha
Published: September 2019

Systems deployed in regulated safety-critical domains (e.g., the medical, nuclear, and automotive domains) are often required to undergo a stringent safety assessment procedure, as prescribed by a certification body, to demonstrate their compliance to one or more certification standards. Assurance cases are an emerging way of communicating safety, security, and dependability, as well as other properties of safety-critical systems in a structured and comprehensive manner. The significant size and complexity of these documents, however, makes the process of evaluating and assessing their validity a non-trivial task and an active area of research. Due to this, efforts have been made to develop and utilize software tools for the purpose of aiding developers and third party assessors in the act of assessing and analyzing assurance cases. This article presents a survey of the various assurance case assessment features contained in 10 assurance case software tools, all of which identified and selected by us via a previously conducted systematic literature review. We describe the various assessment techniques implemented, discuss their strengths and weaknesses, and identify possible areas in need of further research.
Large-scale Semantic Integration of Linked Data
Authors: Mountantonakis Michalis , Tzitzikas Yannis
Published: September 2019

A large number of published datasets (or sources) that follow Linked Data principles is currently available and this number grows rapidly. However, the major target of Linked Data, i.e., linking and integration, is not easy to achieve. In general, information integration is difficult, because (a) datasets are produced, kept, or managed by different organizations using different models, schemas, or formats, (b) the same real-world entities or relationships are referred with different URIs or names and in different natural languages,(c) datasets usually contain complementary information, (d) datasets can contain data that are erroneous, out-of-date, or conflicting, (e) datasets even about the same domain may follow different conceptualizations of the domain, (f) everything can change (e.g., schemas, data) as time passes. This article surveys the work that has been done in the area of Linked Data integration, it identifies the main actors and use cases, it analyzes and factorizes the integration process according to various dimensions, and it discusses the methods that are used in each step. Emphasis is given on methods that can be used for integrating several datasets. Based on this analysis, the article concludes with directions that are worth further research.