bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of Inlet Boundary Conditions on Fuel-Air Mixing at Supercritical Conditions
Authors: Harris Zachary , Bittle Joshua , Agrawal Ajay
Published: December 2020

Advanced engine design and alternative fuels present the possibility of fuel injection at purely supercritical conditions in diesel engines and gas turbines. The complex interactions that govern this phenomenon still need significant research for reliable modeling efforts. Boundary conditions for fuel injection are critical to accurate simulation. However, the flow inside the injector itself is often omitted to reduce the computational efforts, and thus, velocity, mass flux, or total pressure is specified at the injector exit (or domain inlet), often with an assumed top hat profile and assumed turbulence levels. Past studies have shown that such simplified inlet boundary treatment has minimal effects on the results for fuel injection in the compressed liquid phase. However, the validity of this approach at supercritical fuel injection conditions has not been assessed so far.

In this study, comprehensive real-gas and binary fluid mixing models have been implemented for computational fluid dynamic (CFD) analysis of fuel-air mixing at supercritical conditions. The model is verified using prior CFD results from the literature. Next, the model is used to investigate the effects of the shape of axial velocity and mass fraction profiles at the inlet boundary with the goal to improve the comparison of predictions to experimental data. Results show that the boundary conditions have a significant effect on the predictions, and none of the cases match precisely with experimental data. The study reveals that the physical location of the inlet boundary might be difficult to infer correctly from the experiments and highlights the need for high-quality, repeatable measurements at supercritical conditions to support the development of relevant high-fidelity models for fuel-air mixing.
Experimental and Numerical Study on the Motion Characteristics of Cylinder Oil and the Suppressing Methods for Abnormal Combustion in Low-Speed Dual-Fuel Marine Engine
Authors: Gong Zhen , Qu Wenjing , Pan Min , Feng Liyan
Published: December 2020

The auto-ignition of cylinder oil droplets could trigger pre-ignition, the most threatening abnormal combustion in low-speed two-stroke Otto cycle dual-fuel engines. In this study, both the experiment of cylinder oil stripping and numerical simulation of in-cylinder charge motion were conducted to reveal the motion state of cylinder oil near scavenging ports and its spatial distribution after entering combustion chamber. Further, a measure to suppress the occurrence of abnormal combustion was also investigated by numerical study. Experimental results illuminate that cylinder oil both in the form of film and single droplet would strip under the flow velocity of engine’s scavenging ports, which demonstrated the oil stripping near scavenging ports was one of its pathways into cylinder. Numerical results indicate that at high-load condition, the gathered region of oil-vapor mainly located near cylinder wall. In contrast, at low-load condition, gathered region of oil-vapor distributed near cylinder wall and the dead-region under exhaust valve. Auto-ignition of oil and pre-ignition of natural-gas were more likely to occur in these gathered regions of oil-vapor. Decreasing engine load reduced scavenging pressure, which raised the residual mass of in-cylinder oil. And the reduction of the diameter of stripped cylinder oil droplets promoted oil evaporation, which increased the oil concentration in the gathered region of oil-vapor. These two factors could further intensify the occurrence tendency of auto-ignition of cylinder oil. Moreover, numerical results also show that the combination of proper increase of downward angle of natural-gas injector and the advance of injection timing could significantly improve the mixture homogeneity and decrease the escaping ratio of natural-gas. The rich-fuel region near cylinder wall and under exhaust valve reduced apparently as well, which meant fuel concentration in gathered regions of oil-vapor decreased. The reduction of pre-mixture concentration in gathered region of oil-vapor could decrease the occurrence possibility of auto-ignition of cylinder oil. Thus the occurrence tendency of pre-ignition of natural-gas and subsequent severe abnormal combustion could also be inhibited.
The Experimental Study of the Inner Insulated Turbocharger Turbine
Authors: Liu Yang , Madamedon Misan , Burke Richard , Werner Jürgen
Published: December 2020

For turbocharged diesel engine systems, emission reduction is the most significant challenge that manufacturers should overcome. In response to the emission reduction challenge most turbocharged diesel engine systems have adopted complex exhaust aftertreatment systems. Due to the current stringent emission regulation, exhaust aftertreatment system nowadays needs to discover new methods to increase its efficiency of pollution conversion.

Increasing the inlet temperature of aftertreatment systems can help reduce the light-off time. Whilst most methods to do this involve increases in fuel consumption (retarded injection, engine throttling), insulating the turbocharger turbine to reduce heat loss does not have this drawback.

This paper presents a simulation and experimental study the performance of a turbocharger with inner insulated turbine housing, compared with the standard turbocharger (same turbine wheel without inner insulation). Both turbochargers were tested on an engine gas stand test rig with a 2.2L prototype engine acting as an exhaust gas generator. In a steady state condition, the insulated turbocharger can achieve 5 to 14K higher turbine outlet temperature depending on the engine speed and load conditions.

Three types of transient tests were implemented to investigate turbocharger turbine heat transfer performance. The test plan was designed to the engine warm up, step load transient, WLTC cycle and simplified RDE cycle. In the engine warm up test result, the temperature drops between the turbine inlet and outlet was reduced by 4K with the insulated turbine housing. In the results of step load transient test, the turbine with insulated turbine housing was observed to get only 4K temperature benefit but with 2kRPM higher turbocharger speed under the same turbocharger inlet and outlet boundary conditions. In the WLTC cycle test result, turbocharger average speed was increased by 0.8kRPM due to the increased enthalpy of the turbine with insulation, the turbine outlet temperature has an average 1.7K improvement.

The experimental results were used to parameterise a simple, 1D, lumped capacitance model which could predict similar aerodynamic behaviour of the two turbines (turbine housing insulated and non-insulated). However, current model has less accuracy in highly transient process as the heat transfer coefficients are unchangeable in each process. The turbine outlet temperature got at most 10K error for the turbine with non-insulated housing and 13K error for the insulated one. The model was shown to over-estimate the benefits of the inner insulation for 1K in turbine outlet temperature.
Effect of Thermal Boundary Conditions on Propagation of Non-Equidiffusive Flames
Authors: Akkerman Vyacheslav (Slava)
Published: December 2020

Boundary conditions constitute one of the key factors influencing combustion in chambers with large aspect ratios such as narrow channels or pipes. Specifically, the flame shape and propagation velocity are impacted by wall friction and wall heat transfer. Both factors continuously influence the shape of the flame front, thereby resulting in its larger surface area as compared to a planar flame front. Such a corrugated flame consumes more fuel per unit time and thereby propagates faster than the planar flame at the same thermal-chemical conditions. Consequently, a flame accelerates due to the boundary conditions. In the recent years, there have been many studies scrutinizing the role of boundary conditions in flame acceleration scenario by means of analytical formulations, numerical studies or experimental measurements. However, the majority of these works was limited to equidiffusive flames, where the thermal-to-mass diffusivity ratio (the Lewis number; Le) is unity. In this respect, the present work removes this limitation by analyzing non-equidiffusive (Le < 1 or Le > 1) flames propagating in pipes of various widths. Specifically, a parametric study has been conducted by means of simulations of the basic hydrodynamic and combustion equations. In this particular study, two-dimensional channels with smooth walls and different thermal conditions such as isothermal and adiabatic walls, have been employed for various Lewis numbers in the range 0.2 ≤ Le ≤ 2.0, and for various Reynolds number associated with the flame propagation in the range 5 ≤ Re ≤ 30. As a result, a strong coupling between the wall conditions and the variations of the Lewis and Reynolds numbers is demonstrated. Specifically, it is observed that the increase in the Lewis number results in moderation of flame tip acceleration. It is also found that there is a change in the burning rate and surface area of the flame front at the lower Lewis numbers, where flames appear unstable against the diffusional-thermal flame instability. Moreover, a substantial difference between the cases of isothermal and adiabatic wall conditions is demonstrated.
Sensorimotor adaptation of speech depends on the direction of auditory feedback alteration
Authors: Kothare Hardik , Raharjo Inez , Ramanarayanan Vikram , Ranasinghe Kamalini , Parrell Benjamin , Johnson Keith , Houde John F. , Nagarajan Srikantan S.
Published: December 2020

A hallmark feature of speech motor control is its ability to learn to anticipate and compensate for persistent feedback alterations, a process referred to as sensorimotor adaptation. Because this process involves adjusting articulation to counter the perceived effects of altering acoustic feedback, there are a number of factors that affect it, including the complex relationship between acoustics and articulation and non-uniformities of speech perception. As a consequence, sensorimotor adaptation is hypothesised to vary as a function of the direction of the applied auditory feedback alteration in vowel formant space. This hypothesis was tested in two experiments where auditory feedback was altered in real time, shifting the frequency values of the first and second formants (F1 and F2) of participants' speech. Shifts were designed on a subject-by-subject basis and sensorimotor adaptation was quantified with respect to the direction of applied shift, normalised for individual speakers. Adaptation was indeed found to depend on the direction of the applied shift in vowel formant space, independent of shift magnitude. These findings have implications for models of sensorimotor adaptation of speech.
Dihydrotanshinone I Is Effective against Drug-Resistant Helicobacter pylori
In Vitro
and
In Vivo
Authors: Luo Peipei , Huang Yanqiang , Hang Xudong , Tong Qian , Zeng Liping , Jia Jia , Zhang Guoxin , Bi Hongkai
Published: December 2020

Helicobacter pylori
is a major global pathogen and has been implicated in gastritis, peptic ulcer, and gastric carcinoma. The efficacy of the extensive therapy of
H. pylori
infection with antibiotics is compromised by the development of drug resistance and toxicity toward human gut microbiota, which urgently demands novel and selective antibacterial strategies.
Nitric Oxide Circumvents Virus-Mediated Metabolic Regulation during Human Cytomegalovirus Infection
Authors: Mokry Rebekah L. , Schumacher Megan L. , Hogg Neil , Terhune Scott S.
Published: December 2020

Human cytomegalovirus is a prevalent pathogen that can cause serious disease in patients with compromised immune systems, including transplant patients and during congenital infection. HCMV lytic replication likely occurs in localized sites of infection with immune cells infiltrating and releasing nitric oxide with other effector molecules.
The Campotosto linkage fault zone between the 2009 and 2016 seismic sequences of central Italy: Implications for seismic hazard analysis
Authors: Tondi Emanuele , Jablonská Danica , Volatili Tiziano , Michele Maddalena , Mazzoli Stefano , Pierantoni Pietro Paolo
Published: December 2020

In the last decade central Italy was struck by devastating seismic sequences resulting in hundreds of casualties (i.e., 2009-L′Aquila moment magnitude [Mw] = 6.3, and 2016-Amatrice-Visso-Norcia Mw max = 6.5). These seismic events were caused by two NW-SE−striking, SW-dipping, seismogenic normal faults that were modeled based on the available focal mechanisms and the seismic moment computed during the relative mainshocks. The seismogenic faults responsible for the 2009-L′Aquila Mw = 6.3 (Paganica Fault—PF) and 2016-Amatrice-Visso-Norcia Mw max = 6.5 (Monte Vettore Fault—MVF) are right-stepping with a negative overlap (i.e., underlap) located at the surface in the Campotosto area. This latter was affected by seismic swarms with magnitude ranging from 5.0 to 5.5 during the 2009 seismic sequence and then in 2017 (i.e., a few months later than the mainshocks related with the 2016 seismic sequence).

In this paper, the seismogenic faults related to the main seismic events that occurred in the Campotosto Seismic Zone (CSZ) were modeled and interpreted as a linkage fault zone between the PF and MVF interacting seismogenic faults. Based on the underlap dimension, the seismogenic potential of the CSZ is in the order of Mw = 6.0, even in the case that all the faults belonging to the zone were activated simultaneously. This has important implications for seismic hazard assessment in an area dominated by the occurrence of a major NW-SE−striking extensional structure, i.e., the Monte Gorzano Fault (MGF). Mainly due to its geomorphologic expression, this fault has been considered as an active and silent structure (therefore representing a seismic gap) able to generate an earthquake of Mw max = 6.5−7.0. However, the geological evidence provided with this study suggests that the MGF is of early (i.e., pre- to syn-thrusting) origin. Therefore, the evaluation of the seismic hazard in the Campotosto area should not be based on the geometrical characteristics of the outcropping MGF. This also generates substantial issues with earthquake geological studies carried out prior to the recent seismic events in central Italy. More in general, the 4-D high-resolution image of a crustal volume hosting an active linkage zone between two large seismogenic structures provides new insights into the behavior of interacting faults in the incipient stages of connection.
Acrokeratosis paraneoplastica (Bazex syndrome) as the presenting sign of pancreatic adenocarcinoma
Authors: Horton Luke , Bedford Lisa M , Daveluy Steven
Published: December 2020

Acrokeratosis paraneoplastica (Bazex syndrome) is a rare paraneoplastic skin condition characterised by acral psoriasiform plaques, with a predilection for the nose, ears, hands and feet. It typically presents before the discovery of an internal malignancy and is often misdiagnosed as an inflammatory dermatitis that does not respond to treatment. It is associated with squamous cell carcinoma of the aerodigestive tract and lung, as well as adenocarcinoma of the lung, colon and gastrum. Here, we describe the second reported case of Bazex syndrome in the setting of pancreatic adenocarcinoma and the first such case in a patient of African ancestry.
Rare case of symptomatic calcific tendinopathy of the origin of rectus femoris tendon
Authors: Jethwa Tarang , Abadin Andre , Pujalte George
Published: December 2020

Although calcific tendinopathy of the shoulder is a relatively common clinical diagnosis, calcific tendinopathy of the rectus femoris tendon near its origin at the anterior inferior iliac spine is rare. We present a case of a 53-year-old female avid runner with left hip pain. Clinical evaluation and X-ray imaging led to a diagnosis of calcific tendinopathy of the rectus femoris tendon. The patient was treated conservatively with non-steroidal anti-inflammatory drugs, physical therapy and rest. Calcific tendinopathy of the rectus femoris tendon can occur rarely in active patients and may be a cause of hip pain, responsive to conservative management, but with other treatment options possible if recalcitrant.
Unusual gastric tumour in an adolescent: primary gastric teratoma
Authors: Kumar Rahul , Prajapati Tripti , Verma Rahul , Garg Pankaj Kumar
Published: December 2020

Gastric teratoma is a rare entity beyond infancy and usually presents as a slow-growing asymptomatic abdominal mass. There are a few published reports of these tumours seen in patients beyond the age of 1 year. In resource-constrained population, these masses are usually neglected because of minimal symptoms associated with these tumours. We report a case of a 14-year-old adolescent who was diagnosed to have a large primary gastric teratoma and underwent en bloc excision with wedge resection of the stomach. A systematic review to identify the previously reported cases of primary gastric teratoma in patients of over the age of 1 year in last 50 years yielded only five articles. A high index of suspicion for primary gastric teratomas in young children and adolescents presenting with asymptomatic large abdominal masses would help treat these patients with a curative intent and excellent treatment outcomes.
Severe acute hepatitis E infection presenting with acute abdomen and meningoencephalitis
Authors: Gynthersen Rosa Maja Møhring , Rønn Christian Philip , Brandt Christian Thomas , Mens Helene
Published: December 2020

We present a case of a 50-year-old man admitted due to acute abdomen, icterus and fever. The patient had a history of sufficiently treated type 2 diabetes and a high daily alcohol consumption, no recent travel history and had a strictly heterosexual and monogamous way of living. A full blood count displayed severe elevated liver enzymes. A CT of the abdomen was performed and revealed steatosis but no acute abdominal pathology. During admission, the patient developed signs of meningoencephalitis. A lumbar puncture was performed, and the cerebrospinal fluid revealed lymphocytic pleocytosis consistent with mild inflammation. Furthermore, hepatitis E was found in the blood and the definitive diagnosis was established. The patient gradually recovered and was discharged within 8 days of admission. To the best of our knowledge, we present the second case describing concomitant hepatitis and meningoencephalitis, resolving spontaneously and not giving rise to sequelae.
Disseminated tuberculosis in children—a difficult diagnose depends on how far we can go
Authors: Didel Siyaram , Purohit Abhishek , Vyas Varuna , Kumar Prawin
Published: December 2020

Tuberculosis (TB) is an important public health problem in developing countries. In India, despite substantial efforts targeting TB and its associated risk factors, the number of cases remains high with 2.7 million new cases per year with a minimum 10% case contributed by paediatric TB. Disseminated TB has been increasingly recognised in children in recent times due to the increased prevalence of immune suppression secondary to AIDS and immunosuppressive therapies for various medical disorders and increasing awareness. Here we describe a 5-year-old girl who presented with fever of unknown cause, and her diagnosis of disseminated TB was delayed due to atypical presentation and the paucibacillary nature of paediatric TB. It was a bone marrow examination report which led us to clinch the diagnosis. The case highlights the difficulty in diagnosing disseminated TB and the importance of bone marrow examination in such cases.
Retained gallstones: an elusive complication of laparoscopic cholecystectomy
Authors: Jung JooYeon , Basrai Zahir , Celedon Manuel , Grock Andrew
Published: December 2020

A young, healthy woman presented to the emergency department multiple times with right upper quadrant pain and subjective fevers for over a year after her laparoscopic cholecystectomy. The patient required multiple hospital visits and extensive work-ups before finally being diagnosed with retained gallstones in her abdomen. After surgical removal of the stones, her symptoms resolved completely. The case highlights the challenges in diagnosing retained gallstones, the substantial burdens they can impose on patients, and the importance of prevention and thorough documentation.
Penile squamous cell carcinoma following childhood hypospadias repair
Authors: Ngoo Alexander , Hirst Jodi , Wong David , Winkle David
Published: December 2020

We report a case of a 46-year-old man who presented with recurrent lower urinary tract infections and obstructive voiding symptoms on the background of a proximal hypospadias repair at 4 years of age. A mass was later identified at his distal urethra, which on biopsy was found to be a penile squamous cell carcinoma. The lesion was excised en bloc, and at 10 months post-excision, the patient has no evidence of local or regional recurrence.
Emergency presentation of iatrogenic airway stenosis following intubation in a patient with COVID-19 and its management
Authors: Thong Gerard , Lorenz Harry , Sandhu Guri S , AlYaghchi Chadwan
Published: December 2020

A 59-year-old man presented to the emergency department with recent onset biphasic stridor, dyspnoea and increased work of breathing on the background of prolonged intubation for the novel COVID-19 2 months previously. Flexible laryngoscopy revealed bilateral vocal fold immobility with a soft tissue mass in the interarytenoid region. The patient’s symptoms improved with oxygen therapy, nebulised epinephrine (5 mL; 1:10 000) and intravenous dexamethasone (3.3 mg). The following morning, the patient was taken to theatre, underwent suspension microlaryngoscopy and found to have bilateral fixation of the cricoarytenoid joints and a large granuloma in the interarytenoid area. He underwent cold steel resection of the granuloma and balloon dilatation between the arytenoids, with the hope of mobilising the joints. This failed and CO2laser arytenoidectomy was performed on the left side. The stridor had resolved postoperatively, with normalisation of work of breathing and the patient was discharged home on the first postoperative day.
Holographic entanglement of purification near a critical point
Authors: Amrahi B. , Ali-Akbari M. , Asadi M.
Published: December 2020

In the presence of finite chemical potential $$\mu $$
μ
, we holographically compute the entanglement of purification in a $$2+1$$

2
+
1

- and $$3+1$$

3
+
1

-dimensional field theory and also in a $$3+1$$

3
+
1

-dimensional field theory with a critical point, at which a phase transition takes place. We observe that compared to $$2+1$$

2
+
1

- and $$3+1$$

3
+
1

-dimensional field theories, the behavior of entanglement of purification near critical point is different and it is not a monotonic function of $$\frac{\mu }{T}$$

μ
T

where T is the temperature of the field theory. Therefore, the entanglement of purification distinguishes the critical point in the field theory. We also discuss the dependence of the holographic entanglement of purification on the various parameters of the theories. Moreover, the critical exponent is calculated.
Enhanced tensor non-Gaussianities in presence of a source
Authors: Naskar Abhishek , Pal Supratik
Published: December 2020

We address the possibility of having an enhanced signal for tensor non-Gaussianities in presence of a source, as a signature of Primordial Gravitational Waves. We employ a nearly model-independent framework based on Effective Field Theory of inflation and compute tensor non-Gaussianities therefrom sourced by particle production during (p)reheating to arrive at an enhanced signal strength. We obtain the non-linearity parameters and also find that squeezed limit bispectra are more enhanced than equilateral limit.
Progress in Traditional Chinese Medicine for the Treatment of Migraine
Authors: Huang Yanleng , Ni Ni , Hong Yanlong , Lin Xiao , Feng Yi , Shen Lan
Published: December 2020

Migraine is a recurrent disease with complex pathogenesis and is difficult to cure. At present, commercially available western migraine drugs are prone to generate side effects while treating the disease. Traditional Chinese medicine (TCM) avoids side effects via treatment with the principles of “treating both symptoms and root causes”, “overall adjustment”, and “treatment based on syndrome differentiation”. Three strategies of drug treatment were developed based on the syndromes, i.e., removing stasis, calming liver Yang, and reinforcing deficiency. Prescriptions of removing stasis mostly contain Chuanxiong rhizome (Chuan Xiong) to remove blood stasis by promoting blood circulation and improve properties of hemorheology, and Da Chuan Xiong Formula (DCXF) is a traditional prescription widely used in clinical practice. Prescriptions of calming liver Yang usually take Ramulus Uncariae cum Uncis (Gou Teng) as the main herb, which can calm the liver Yang via improving vasomotor function, and Tian Ma Gou Teng Decoction (TMGTD) is the representative drug. For reinforcing deficiency, Chinese doctors frequently utilize Angelica Sinensis (Dang Gui) and Astragali Radix (Huang Qi) to nourish blood and Qi in order to improve the weak state of human body; Dang Gui Bu Xue Decoction (DGBXD) is the commonly used prescription. These strategies not only treat the symptoms of diseases but also their root causes, and with the features of multiple targets, in multiple ways. Therefore, TCM prescriptions have obvious advantages in the treatment of chronic diseases such as migraine. In this review, we provided an overview of the pathogenesis of migraine and the function of representative TCM preparations in therapy of migraine as well as the mechanism of action according to effective researches, in order to provide reference and clue for further researches.
A GLOBAL VAR ANALYSIS OF GLOBAL AND REGIONAL SHOCK SPILLOVERS TO WEST AFRICAN COUNTRIES
Authors: SIKIRU ABDULSALAM ABIDEMI , SALISU AFEES A.
Published: December 2020

Motivated by the drive to achieve monetary union in the Economic Community of West African States (ECOWAS), the vulnerability of member countries to global and regional shocks is examined, using the global VAR (GVAR) framework so constructed for the purpose. The global shocks are those due to global commodity prices, oil and food prices, while the regional shocks capture the influence of their major trading partners; the United States (US) and China. We estimate a 59-unit GVAR model comprising advanced and emerging economies. Two findings are discernible from the results. First, the constituent countries are vulnerable to both global and regional shocks. Second, after grouping the countries into two recognized divisions [i.e., the West African Economic and Monetary Union (WAEMU) and West African Monetary Zone (WAMZ)], we find significant variations in their response to shocks. These findings have implications on the common monetary zone agenda for the region, particularly as regards to the heterogeneous response and vulnerability of the constituent countries to shocks. Resolving such vulnerabilities is a major requirement for the success of a monetary union.
Resonant optical solitons with conformable time-fractional nonlinear Schrödinger equation
Authors: Seadawy Aly R. , Bilal M. , Younis M. , Rizvi S. T. R.
Published: December 2020

We successfully apply extended rational sine-cosine/sinh-cosh and advance expansion function techniques in this paper. Various kinds of soliton solutions to the conformable time-fractional resonant nonlinear Schrödinger equation (RNLSE) in optical fiber are extracted. We discuss the system with the effects of coefficients like group velocity dispersion, non-Kerr nonlinearity, resonant nonlinearity, and construct optical soliton solution in terms of rational, trigonometric and hyperbolic function solutions with arbitrary parameters. The recovered solutions reveal that the applied approaches are straightforward and efficient to work out the excellent contribution for analyzing several classes of nonlinear partial differential equations (NLPDEs) in engineering and sciences. Moreover, 3D, 2D and contour graphs are sketched with suitable selection of the parameters under the criteria of constraints conditions.
Design of Evolutionary Adaptive Notch Filter for GPS Anti-Jamming System
Authors: Tahouri M. A. , Abbasi M. , Mosavi M. R.
Published: December 2020

GPS signals can be affected easily by interference due to the low power of signals and the long way between the satellites and receivers. Interference cancellation is one of the major challenges in using GPS. One of the most common intentional interferences is Continuous Wave Interference (CWI) jamming and the most popular way to reduce the impact of it on the GPS signal is using an Adaptive Notch Filter (ANF). Two kinds of heuristic Evolutionary Algorithms (EAs) are used to design second-order IIR Evolutionary Adaptive Notch Filter (EANF). The first algorithm is the Genetic Algorithm (GA) and the second one is Particle Swarm Optimization (PSO) algorithm. EAs are used to find answers to the problems in which there is no specific solution, and this is exactly what is needed to fix the digital filter design problems. NF is implemented in FPGA hardware according to the obtained filter coefficients. Finally, the efficiency of the proposed methods is compared with similar methods in terms of different evaluation metrics. The simulation results show about 12% SNR improvement by using GA and 97% RMS improvement by using the PSO method for higher than 50-dB JSRs.
MECHANICAL PROPERTIES ESTIMATION FROM TENSILE TESTING OF AA6063-AISI304L BIMETAL JOINTS FRICTION WELDED WITH DIFFERENT JOINING METHODS
Authors: MURUGAN S. SENTHIL , SATHIYA P. , HAQ A. NOORUL
Published: December 2020

This paper discusses the various joining methods with faying surface modifications used to join AA6063 and AISI304L dissimilar alloys by Rotary Friction Welding (RFW) process at different welding conditions mainly with friction pressure (FP), upset pressure (UP) and friction time (FT). This paper also studies the tensile behavior of the welded joints. The fabricated dissimilar joints were tested using universal testing machine against tensile load, and the mechanical properties of all 30 nos. of weld joints like elongation (%), strength coefficient ([Formula: see text]), strain hardening exponent ([Formula: see text]), strain hardening rate (TS/YS ratio), shear strength, etc. were calculated from the tensile testing results and plotted here with a standard error bar. Hollomon’s equation is considered here to study the stress and strain hardening relation and Von Mises yield criterion is considered for shear and yield stress correlation. Total elongation is also calculated from the initial and final length obtained during the tensile test. Since fracture ductility of the joints depends on the stress, strain, ‘[Formula: see text]’ and ‘[Formula: see text]’ values, it is important to study these mechanical properties and how the tensile results can be used for their estimation is detailed in this paper. The faying surfaces influence the mechanical properties as well.
A simple closed-form approximation for constant elasticity of variance spread options
Authors: Lo C. F. , Zheng X. F.
Published: December 2020

By applying the Lie–Trotter operator splitting method and the idea of the WKB method, we have developed a simple, accurate and efficient analytical approximation for pricing the constant elasticity of variance (CEV) spread options. The derived option price formula bears a striking resemblance to Kirk’s formula of the Black–Scholes spread options. Illustrative numerical examples show that the proposed approximation is not only extremely fast and robust, but it is also remarkably accurate for typical volatilities and maturities of up to two years.
A Fitts’ Law Evaluation of Visuo-haptic Fidelity and Sensory Mismatch on User Performance in a Near-field Disc Transfer Task in Virtual Reality
Authors: Brickler David , Teather Robert J. , Duchowski Andrew T. , Babu Sabarish V.
Published: December 2020

The trade-off between speed and accuracy in precision tasks is important to evaluate during user interaction with input devices. When different sensory cues are added or altered in such interactions, those cues have an effect on this trade-off, and thus, they affect overall user performance. For instance, adding cues like haptic feedback and stereoscopic viewing will result in more realistic user interaction, thus improving performance in these tasks. Also, adding a noticeable disparity between physical and virtual movements creates a mismatch between visual and proprioceptive systems, which generally has a negative effect on performance. In this study, we investigate the effects of haptic feedback, stereoscopic viewing, and visuo-proprioceptive mismatch on how quickly and accurately users complete a virtual pick-and-place task using the PHANToM OMNI. Through this experiment, we find that in the movement phase of a ring transfer, movement time and user performance are affected by haptic feedback and visuo-proprioceptive mismatch, and the main effects of stereoscopic viewing appears to be limited to the more precise step when the ring is around the target peg.
Mo Effect on Natural Passivation and Corrosion Behavior of Duplex Stainless Steels in Alkaline Media
Authors: Yuan Xuwen , Li Wentao , Wang Xuan , Yang Huaiyu
Published: December 2020

The role of Mo in the natural passivation behavior and pitting corrosion resistance of duplex stainless steels (DSSs) in alkaline medium was investigated by X-ray photoelectron spectroscopy and electrochemical analyses as a function of immersion time. It is shown that the Mo participated directly in the formation process of natural passive film, which affected the chemical distribution and thickness of the film by modifying the contents of other species (e.g. Cr oxide). With the increasing of prepassivation time, the oxidized Cr species were gradually enriched in the passive film, and the corrosion resistance of DSSs in alkaline solution containing Cl− was enhanced. Mo greatly improved the pitting corrosion resistance and the tolerance to Cl− attack of the passive film formed on DSS surface by inhibiting the initiation and growth of pitting.
Study of the Performance of a ZnO-NiO/Si Nanocomposite-Based Solar Cell
Authors: Thamri S. , Raouadi M. H , Ezzaouia H.
Published: December 2020

In this work, we fabricated a novel (Zinc Oxide-Nickel Oxide) ZnO-NiO/Si (silicon) solar cells using ZnO-NiO thin films. We synthesized the nanocomposite films at different mixing concentrations and deposited them on silicon. We completed the fabrication of the solar cells by adding silver front and back contacts. The objective of this work is to increase power conversion efficiency for solar cells. We used I-V in the dark and under illumination as well as impedance spectroscopy to highlight the enhancement of the electrical and optoelectronic results. We found that the carriers lifetime reached 6.1 ms, and the series resistance Rs 0.017 Ω cm2 for the ZnO-NiO/Si solar cell. The power conversion efficiency reached 14%. The novel nanocomposite thin film improved solar cell conversion efficiency.
Research on the Technology of Plugging Gushing Water in the Vertical Shaft under Complicated Conditions
Authors: Jia Chuanyang , Wang Hailong , Liu Haiquan , Zhang Guibin , Sheng Kaihua
Published: December 2020

The shaft is the throat of the mine construction, and it is easily disturbed by gushing water, which affects the mine construction progress. Aiming at technical problems under complex hydrogeological conditions in coal mines, such as vertical shaft lining rupture and serious gushing water, single-liquid and double-liquid cement grouting materials are invalid for multiple plugging of gushing water. Combining with geological data to analyze the conditions of the aquifers and water-blocking layer in the shaft, adopting the multifunctional digital electrical method and digital flow measuring instrument can accurately grasp the flow direction and flow velocity and further obtain the aquifer parameters of the main and auxiliary shafts. At the same time, based on the FLAC numerical simulation software, research on the stress, displacement, and plastic failure of the shaft surrounding rock under different water pressures (0.5 times, 1 time, and 2 times the hydrostatic pressure) and comparative analysis of the influence of the water bodies on the shaft surrounding rock are carried out. On this basis, the following are the objectives: (1) research the mechanical properties of polymer chemical material Malisan N and the mechanism of grouting to plugging gushing water and strengthening surrounding rock, (2) formulate the grouting drilling layout and construction technology for the topsoil and bedrock section of the main and auxiliary shafts, and (3) carry out long-term monitoring of the water inflow. The monitoring data showed that the measured water inflow was less than 0.05 m3/h after the grouting of the shaft surrounding rock, which achieved the purpose of preventing the shaft linings from rupturing, plugging the gushing water, and stabilizing the aquifer water pressure.
Hysterosalpingography Findings and Jimah Ratio of the Uterine Cavity in Women with Infertility in Central Region, Ghana
Authors: Jimah Bashiru Babatunde , Gorleku Philip , Baffour Appiah Anthony
Published: December 2020

Background. Infertility affects from 1.3% to 25.7% of couples worldwide and, especially, from 14.5% to 16.4% in Africa. Hysterosalpingography (HSG) is a diagnostic modality that is considered both common and efficient. It is used to investigate abnormalities of the uterine cavity and fallopian tubes. This study assessed the spectrum of findings on HSG among women with infertility in the Central Region (Ghana). Methods. We conducted a prospective cross-sectional study to examine 203 infertile women undergoing HSG work-up at the Cape Coast Teaching Hospital. The exclusion criteria were acute infection of the vagina or cervix and active vaginal bleeding or pregnancy. Data were entered with Microsoft Excel and analyzed using SPSS version 21. Results. A total of 203 women were enrolled, and eighty-five (41.87%) of the women had at least one or more abnormalities. The mean age was 32.9 years with majority of the women within 30–39 years (61.08%). More than half (50.74%) of the women presented with secondary infertility, while age of women (

p
=
0.004

) and duration of infertility (0.034) were found to be in association with the type of infertility. Uterine findings were predominantly capacious uterine cavity (45.1%) and uterine fibroids (33.3%), while fallopian tube findings included bilateral blockage (24.2%), right unilateral proximal blockage (17.7%), loculated spillage (16.1%), and left unilateral proximal blockage (16.1%). The range of normal uterine cavity size, measured as ratio (Jimah ratio) of intercornual diameter to interiliac diameter was 0.2–0.45, with a mean of 0.36. Conclusion. Secondary infertility was the commonest indication for HSG in the study, and a significant proportion of infertile women had abnormalities. Abnormalities were higher in the fallopian tubes than the uterus, while capacious uterine cavity, uterine fibroid, and bilaterally blocked tubes were the top three abnormalities found.
Functional Adrenal Collision Tumor in a Patient with Cushing’s Syndrome
Authors: Zhou Cathy , Fananapazir Ghaneh , Campbell Michael J.
Published: December 2020

Adrenal collision tumors are rare and produce unique diagnostic challenges for clinicians. We report the case of a 45-year-old woman with obesity and diabetes mellitus and an incidentally-discovered adrenal mass containing macroscopic fat, thought to be a myelolipoma. A functional workup confirmed adrenocorticotropic hormone- (ACTH-) independent Cushing’s syndrome. The patient underwent a successful laparoscopic adrenalectomy with pathology showing an adrenal collision tumor consisting of an adrenocortical adenoma and a myelolipoma. Postoperatively, the clinical symptoms, body mass index, and hemoglobin A1C all improved. Clinicians should consider a functional workup in patients with radiographically diagnosed myelolipomas as some may prove to be hormonally active collision tumors.
The Value of Contrast‐Enhanced Transesophageal Echocardiography in the Detection of Cardiac Right‐to‐Left Shunt Related with Cryptogenic Stroke and Migraine
Authors: Zhang Huiqin , Huang Wenyan , Lan Tingyu , Zhang Meng , Yang Jing , Zhang Hongxia , Du Lijuan
Published: December 2020

Purpose. To analyze the characteristics of right‐to‐left shunt (RLS) in patients with cryptogenic stroke and migraine by contrast‐enhanced transesophageal echocardiography (c‐TEE). Methods. The study population consisted of 330 patients with cryptogenic stroke and 330 patients with migraine who suspected PFO. All of them received c‐TEE examination successfully. In terms of c‐TEE analyses, RLS could be diagnosed when microbubbles were visualized in the transition from the right atrium to the left atrium. For semiquantitative analysis, a small amount of RLS was grade 1, indicating 1‐10 microvesicles per frame could be seen in the left atrium, a moderate amount of RLS was grade 2, indicating 11‐30 microvesicles per frame could be seen in the left atrium, and a large amount of RLS was grade 3, indicating more than 30 microvesicles per frame, or the left atrium is filled with microvesicles. Results. A total of 660 patients were analyzed in the study. PFO‐RLS was detected in 348 (348/660, 52.7%) cases by TEE, while in 392 (392/660, 59.3%) cases by c‐TEE. Simultaneously, P‐RLS was detected in 239 (239/660, 36.2%) cases by c‐TEE. Among 330 patients with cryptogenic stroke, PFO‐RLS was detected in 198 cases; according to the c‐TTE method (198/330, 60.0%), concurrently, 83 participants suffered from PFO‐RLS and P‐RSL (83/330, 25.1%), including 1 case with PFO and pulmonary arteriovenous fistula. Among 330 patients with migraine, PFO‐RLS was detected in 194 cases; according to the c‐TTE method (194/330, 58.7%), specifically, 90 participants suffered from PFO‐RLS and P‐RSL (90/330, 27.2%). There was no statistical significance between the two groups. P‐RLS singly was detected in 28 cases with cryptogenic stroke, while in 38 cases with migraine, excluding from pulmonary arteriovenous fistula by CTA examination. In addition, semiquantitative results on c‐TTE grading of RLS were compared between the two groups: grade 1 RLS in the migraine group (144/322) was significantly higher than that in the cryptogenic stroke group (71/309) (P < 0.05). Grade 3 RLS in the cryptogenic stroke group (113/309) was significantly higher than that in the migraine group (67/322) (P < 0.05). For grade 2 RLS, there was no statistical difference between the two groups (P = 0.12). Conclusions. c‐TEE can increase the positive rate of PFO diagnosis compared with TEE color Doppler. There is no significant difference in the incidence of PFO‐PLS and P‐RLS between the cryptogenic stroke group and the migraine group. The grades 2‐3 RLS are mainly detected in the cryptogenic stroke group, while grades 1‐2 RLS are mostly detected in the migraine group.
A New Algorithm for Solving Large-Scale Generalized Eigenvalue Problem Based on Projection Methods
Authors: Nedamani F. Abbasi , Sheikhani A. H. Refahi , Najafi H. Saberi
Published: December 2020

In this paper, we consider four methods for determining certain eigenvalues and corresponding eigenvectors of large-scale generalized eigenvalue problems which are located in a certain region. In these methods, a small pencil that contains only the desired eigenvalue is derived using moments that have obtained via numerical integration. Our purpose is to improve the numerical stability of the moment-based method and compare its stability with three other methods. Numerical examples show that the block version of the moment-based (SS) method with the Rayleigh–Ritz procedure has higher numerical stability than respect to other methods.
Spatial Visualisation of Ethnic Structure Changes in the Apuseni Mountains (Romania) 1880–2011
Authors:   Faculty of Geography, Babeș-Bolyai University, Cluj-Napoca, Lung Mădălin-Sebastian , Muresan Gabriela-Alina ,   Faculty of Geography, Babeș-Bolyai University, Cluj-Napoca
Published: December 2020

This study aims to present a comparative analysis of the ethnic structure of the population in the Apuseni Mountains (in Romania) during three censuses: in 1880, 1930, and 2011. It emphasises ethnicity continuities and discontinuities, as well as the historical moments that left their mark on that evolution. Statistical data were processed, resulting in the tables showing the ethnic structure of the Apuseni, with absolute as well as relative (percentage) values for each ethnic group. Data were also processed with the aid of ArcGIS 10.3, generating maps of the territorial distribution of the ethnic groups for each administrative-territorial unit. The results show that Romanians maintained their continuity in the mountain area, while other ethnicities changed significantly in terms of numbers and percentages of the total population. The Jewish community was persecuted during the Second World War, finding themselves on the brink of disappearance at the 2011 census. German communities suffered from the socialist policies of deportation to the Soviet Union and other states. Slovaks, deeply affected by industrial restructuring, began to emigrate after the fall of communism in 1989. The most dynamic ethnic group are the Roma, who, according to the censuses, continuously increased in number and percentage.
SWI/SNF Complex Mutations Promote Thyroid Tumor Progression and Insensitivity to Redifferentiation Therapies
Authors: Saqcena Mahesh , Leandro-Garcia Luis Javier , Maag Jesper L.V. , Tchekmedyian Vatche , Krishnamoorthy Gnana P. , Tamarapu Prasanna P. , Tiedje Vera , Reuter Vincent , Knauf Jeffrey A. , de Stanchina Elisa , Xu Bin , Liao Xiao-Hui , Refetoff Samuel , Ghossein Ronald , Chi Ping , Ho Alan L. , Koche Richard P. , Fagin James A.
Published: December 2020

Mutations of subunits of the SWI/SNF chromatin remodeling complexes occur commonly in cancers of different lineages, including advanced thyroid cancers. Here we show that thyroid-specific loss of Arid1a, Arid2, or Smarcb1 in mouse BRAFV600E-mutant tumors promotes disease progression and decreased survival, associated with lesion-specific effects on chromatin accessibility and differentiation. As compared with normal thyrocytes, BRAFV600E-mutant mouse papillary thyroid cancers have decreased lineage transcription factor expression and accessibility to their target DNA binding sites, leading to impairment of thyroid-differentiated gene expression and radioiodine incorporation, which is rescued by MAPK inhibition. Loss of individual SWI/SNF subunits in BRAF tumors leads to a repressive chromatin state that cannot be reversed by MAPK pathway blockade, rendering them insensitive to its redifferentiation effects. Our results show that SWI/SNF complexes are central to the maintenance of differentiated function in thyroid cancers, and their loss confers radioiodine refractoriness and resistance to MAPK inhibitor–based redifferentiation therapies.

Significance:

Reprogramming cancer differentiation confers therapeutic benefit in various disease contexts. Oncogenic BRAF silences genes required for radioiodine responsiveness in thyroid cancer. Mutations in SWI/SNF genes result in loss of chromatin accessibility at thyroid lineage specification genes in BRAF-mutant thyroid tumors, rendering them insensitive to the redifferentiation effects of MAPK blockade.

This article is highlighted in the In This Issue feature, p. 995