bluuebunny/crossref_metadata_2025 huggingface dataset:
Comprehensive performance analysis of a shearer drum in a complicated seam based on discrete element method
Authors: Zhao Lijuan , Zhang Meichen , Shi Baisheng , Liu Xionghao , Wang Yadong
Published: August 2021

Drum of Shearer undertakes the main function of coal falling and loading, and its performance directly affects the working efficiency of the shearer. Therefore, in order to realize the analysis of the performance of the shearer drum, the MG2 × 55/250-BW shearer drum was the engineered object. Combining the physical and mechanical properties experiment results of coal samples, the coupling model of the drum cutting in complex coal seam was established using discrete element method. The falling-coal characteristics of the spiral drum were studied under different working conditions, and the falling-coal trajectories of the coal and rock particles were fitted. Based on a virtual prototype, the variations of the coal loading rate and lump coal rate with different design parameters were determined by studying the falling-coal effect and loading performance of the drum. Considering the drum performance, multi-objective optimization theory was used to determine the optimal operating and structural parameters. The results indicate that, in the process of drum cutting, the cutting depth has the most significant effect on the coal loading rate, while, the blade spiral angle has the least significant. Moreover, with the increase of the cutting depth of drum and the traction speed, the lump coal rate increases. While, with the increase of the drum rotation speed and the blade spiral angle, the lump coal rate decreases. It is found that when the cutting depth of the drum is 597 mm, the traction speed is 5.4 m/min, the drum rotation speed is 104.8 r/min, and the blade spiral angle is 12° the performance of the drum is optimal. Compared with the falling-coal trajectories before optimization, the displacements of the coal and rock particles ejected along the optimal falling-coal trajectories increase in the coal loading direction. The loading rate and lump coal rate of the drum increase by 6.05% and 12.27%, respectively. The load fluctuation of the drum decreases, and the productivity increases.
Numerical and experimental investigations on the effect of target thickness and solution treatment on the ballistic behaviour of AA7075 thick plates
Authors: Praveen R , Koteswara Rao SR , Damodaram R , Suresh Kumar S
Published: August 2021

The influence of target thickness and solution treatment on the ballistic behaviour of AA7075 targets has been investigated by both numerical and experimental methods. In numerical simulation, the target thickness was varied from 19 to 26 mm and an Ogive nose shaped projectile of 7.62 mm diameter with inlet velocities ranging between 800–875 m/s was considered. In order to justify the numerical observations, high velocity ballistic experiments were conducted on AA7075-T651 and the solution treated plates of various thicknesses (12, 16, 18, 20, 22 and 25 mm). For this experimental study, a deformable form projectile with dimensions of 7.62 × 51 mm and an inlet velocity of 850 ± 20 m/s was used. Microstructures of ballistic test samples were analysed using an optical microscope. Numerical analysis using ABAQUS predicted the minimum thickness required to resist complete penetration to be 20 mm in the case of AA7075 plates in the T651 condition, while experimental results showed it to be 21 mm. In the case of AA7075 solution treated plates, numerical simulation analysis predicted the minimum required plate thickness to resist complete penetration to be 24 mm, while the experimental results showed it to be 23 mm. Post ballistic microstructure analysis revealed that there was no change in the microstructure in the AA7075-T651 condition plates. Solution treated plates showed deformation of grains nearer to the impact region with the formation of adiabatic shear bands. In the case of the T651 plate, the mode of fracture was brittle, resulting in splinters, whereas it was petalling in the case of the solution-treated plates. The numerically predicted depth of penetration on both targets was reasonably close to experimental results with an average of 4% error.
Experimental investigation on fluid structure and full-cone spray characteristics of a jet-swirl atomizer using shadowgraph technique
Authors: Shafaee Mazyar , Elkaie Abbas , Hassani Mohammad Amin
Published: August 2021

Full-cone spray is quite important in spray cooling and catalytic combustion applications; however, it is not extensively studied. Besides, the liquid spray is relatively a non-uniform structure especially along longitudinal axis which includes different sizes and distribution of droplets. The few published experimental studies are limited to calculate some of the spray characteristics on a certain plane located downstream of the nozzle exit. Therefore, the spray parameters representing fluid structure, droplets mean diameter, and their distribution in different cross sections from nozzle exit are considered in this study. Accordingly, a jet-swirl atomizer with pressure-swirl full-cone spray is investigated where all important full-cone spray characteristics are considered at different planes from nozzle exit. The spray images are obtained with a shadowgraph technique and are analyzed to obtain the Sauter mean diameter (SMD), D10, and droplet size distribution along with the spray structure, spray cone angle, and discharge coefficient. The experimental results are verified based on the pre-published numerical studies on the same atomizer. The experimental and numerical results show good agreement. Moreover, the results show that the SMD is increased by moving away from center of spray to its edges, and the droplets number density is increased in central regions. The increased droplets number density leads to the greater external forces which create smaller droplets. In contrast, larger particles exist in peripheral parts due to the less droplets concentration. Furthermore, and far away from the exit nozzle, the SMD values are decreased due to the increased aerodynamic forces and oscillations. The droplets dispersion including spray density in radial and axial directions is also observed using spray density images.
Novel and simplified optimisation pathway using response surface and design of experiments methodologies for dental implants based on the stress of the cortical bone
Authors: Freitas João PO , Agostinho Hernandez Bruno , Gonçalves Paulo J Paupitz , Baptista Edmea C , Capello Sousa Edson A
Published: August 2021

Dental implants are widely used as a long-term treatment solution for missing teeth. A titanium implant is inserted into the jawbone, acting as a replacement for the lost tooth root and can then support a denture, crown or bridge. This allows discreet and high-quality aesthetic and functional improvement, boosting patient confidence. The use of implants also restores normal functions such as speech and mastication. Once an implant is placed, the surrounding bone will fuse to the titanium in a process known as osseointegration. The success of osseointegration is dependent on stress distribution within the surrounding bone and thus implant geometry plays an important role in it. Optimisation analyses are used to identify the geometry which results in the most favourable stress distribution, but the traditional methodology is inefficient, requiring analysis of numerous models and parameter combinations to identify the optimal solution. A proposed improvement to the traditional methodology includes the use of Design of Experiments (DOE) together with Response Surface Methodology (RSM). This would allow for a well-reasoned combination of parameters to be proposed. This study aims to use DOE, RSM and finite element models to develop a simplified optimisation analysis method for dental implant design. Drawing on data and results from previous studies, two-dimensional finite element models of a single Branemark implant, a multi-unit abutment, two prosthetic screws, a prosthetic crown and a region of mandibular bone were built. A small number of combinations of implant diameter and length were set based on the DOE method to analyse the influence of geometry on stress distribution at the bone-implant interface. The results agreed with previous studies and indicated that implant length is the critical parameter in reducing stress on cortical bone. The proposed method represents a more efficient analysis of multiple geometrical combinations with reduced time and computational cost, using fewer than a third of the models required by the traditional methods. Further work should include the application of this methodology to optimisation analyses using three-dimensional finite element models.
Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy
Authors: Aihara Aya , Goude Anders , Bernhoff Hans
Published: August 2021

This article presents the aerodynamic noise prediction of a NACA 0012 airfoil in stall region using Large Eddy Simulation and the acoustic analogy. While most numerical studies focus on noise for an airfoil at a low angle of attack, prediction of stalled noise has been made less sufficiently. In this study, the noise of a stalled airfoil is calculated using the spanwise correction where the total noise is estimated from the sound source of the simulated span section based on the coherence of turbulent flow structure. It is studied for the airfoil at the chord-based Reynolds number of 4.8 × 105 and the Mach number of 0.2 with the angle of attack of 15.6° where the airfoil is expected to be under stall condition. An incompressible flow is resolved to simulate the sound source region, and Curle’s acoustic analogy is used to solve the sound propagation. The predicted spectrum of the sound pressure level observed at 1.2 m from the trailing edge of the airfoil is validated by comparing measurement data, and the results show that the simulation is able to capture the dominant frequency of the tonal peak. However, while the measured spectrum is more broadband, the predicted spectrum has the tonal character around the primary frequency. This difference can be considered to arise due to insufficient mesh resolution.
Chemical and biological characterization of sulfated chitosan oligomer as heparin mimics
Authors: Kocabay Samet , Bahar Mehmet Refik , Tekin Suat , Akkaya Recep , Akkaya Birnur
Published: August 2021

In the present study, chitosan oligomer was modified to sulfated chitosan oligomer (ShCsO) to mimic heparin. Its chemical structure was determined by infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and thermogravimetric analysis. The results showed that the FT-IR spectrum band at 799 cm−1 corresponds to C–O–S and that at 1212 cm−1 corresponds to S=O bond stretching, which prove that the sulfate groups are incorporated into chitosan oligomer successfully. The antimicrobial activity of ShCsO against to Bacillus subtilis in 1% concentration was 89.1 ± 1.7% . The IC50 (μg/ml) of ShCsO was 67.75, 56.07, 85.47, and 84.68 for A2780, MCF-7, DU-145, and HepG2, respectively. The results show that this newly synthesized material is a potential candidate to heparin-like chitosan derivatives. According to the literature, it was the first time that chitosan oligomer was modified to mimic heparin.
A 360-Degree View of a Hospital by Analysing Patient’s Online Reviews Using Fuzzy Sentiment Analysis
Authors: Gour Alekh , Kumari Sony
Published: August 2021

Millions of people use Internet for developing new skills, booking online tickets, socialising, etc. Out of the sundry activities, giving online reviews by customers has become very customary these days and the fastest medium to make one’s voice heard. With the advent of analytics, more specifically, text mining, the online reviews of the customers have made a huge difference in shaping the future strategies of the companies and have also helped them to study the customer responses of their rivals. In an effort to help hospitals analyse the patient’s reviews present online on various social media platforms, this paper analyses the 659 reviews of people across the nation, on one of the best medical college and hospital of India, All India Institute of Medical Sciences, New Delhi. An attempt is made in this article to develop fuzzy sentiment analysis model with integration of naïve base classifier, which helps to analyse reviews of different hospitals and can come up with their own social media competitive analysis strategy. The results reveal the value text mining can bring to the table for any hospital and the immense business value that it holds.
Determinants of Quality of Health Insurance Services in Brazil
Authors: Júnior Djalma Silva Guimarães , Soares Eduardo José Oenning , de Oliveira Lucas Ambrósio Bezerra , de Medeiros Denise Dumke
Published: August 2021

This research proposes the application of a hierarchical and multidimensional model for quality measurement in health insurance services. The modelling assumes that perceived health insurance quality is composed of a three-stage hierarchical structure, which includes primary quality dimensions, interaction, environment conditions and outcome and each primary dimension is supported from the following sub-dimensions: Interaction quality (attitude), behaviour and expertise; environment conditions quality (environment conditions), design and social factors; and outcome quality (waiting time, tangibles and valence). For model validation, structural equation system is used. The application through structural equation modelling showed that only the outcome quality is significant to the overall perceived quality with the health insurance, and significant sub-dimensions for the study were social conditions, waiting time and tangible. The application of the modelling provided the estimation of the determinants of quality in the service. The determinants of perceived quality can help managers in the direction of improvement actions in order to increase the quality perceived by the users of health insurance services.
Bringing the EU up to speed in the protection of living standards through fundamental social rights: Drawing positive lessons from the experience of the Council of Europe
Authors: Aranguiz Ane
Published: August 2021

Ever since the adoption of the European Pillar of Social Rights, the EU seems committed to explore and expand its social dimension to deliver a decent standard of living to the European society. This new endeavour gives rise to a number of questions, not least regarding how the notion of a standard of living that is compatible with a life in dignity ought to be interpreted and what the obligations of Member States are in this quest. The aim of this contribution is precisely to shed some light on these questions. To this end, the article looks into how different (quasi)judicial bodies have interpreted fundamental rights that entitle individuals to minimum subsistence resources that are deemed to achieve a standard of living that is compatible with the right to human dignity. In particular, it analyses how the ECJ, the ECtHR and the ECSR have interpreted (minimum) living standards through different fundamental rights. It then suggests a number of ‘learning points’ for the ECJ to draw from the experience of the other two bodies and emphasizes the need for building solid bridges between the three.
Verminous meningoencephalomyelitis in a red kangaroo associated with Angiostrongylus cantonensis infection
Authors: Patial Sonika , Delcambre Brooke A. , DiGeronimo Peter M. , Conboy Gary , Vatta Adriano F. , Bauer Rudy
Published: August 2021

Angiostrongylus cantonensis is a zoonotic parasitic helminth that normally resides in the pulmonary arteries and the right ventricle of rats ( Rattus sp.), the definitive host, where it causes little disease. Humans, dogs, opossums, and various zoo animals are “accidental” hosts. Here we report verminous meningoencephalomyelitis caused by A. cantonensis in a 9-mo-old male red kangaroo ( Macropus rufus). The kangaroo was first presented lethargic, recumbent, and hypothermic, with severe muscle wasting. Within 3 wk, he progressed to non-ambulatory paraparesis and died. Gross examination revealed multifocal areas of dark-brown discoloration, malacia, and cavitation in the brain and the spinal cord. Histologically, there were several sections of nematodes surrounded by extensive areas of rarefaction, hemorrhage, spongiosis, neuronal necrosis, and gliosis. Based on size, morphology, and organ location, the nematodes were identified as subadult males and females. Interestingly, an eosinophilic response was largely absent, and the inflammatory response was minimal. A. cantonensis infection had not been reported previously in a red kangaroo in Louisiana or Mississippi, to our knowledge. Our case reaffirms the widespread presence of the helminth in the southeastern United States and indicates that A. cantonensis should be considered as a differential in macropods with neurologic clinical signs in regions where A. cantonensis is now endemic.
Body Image and Eating Disorders Among South Asian American Women: What Are We Missing?
Authors: Goel Neha J. , Thomas Brogan , Boutté Rachel L. , Kaur Brahmpreet , Mazzeo Suzanne E.
Published: August 2021

This study used focus group methodology to examine South Asian (SA) American women’s conceptualizations of eating disorders (EDs) and body dissatisfaction, and their perspectives regarding cultural influences on these conditions. Using a qualitative descriptive approach, seven focus groups were conducted ( N = 54, mean age = 20.11 years, SD = 2.52). Themes ( n = 15) were organized according to the amended objectification theory framework. Women described experiences of cultural stressors specifically related to living in the United States, and weight stigma from multiple sources, especially older women (e.g., mothers, relatives, and aunties). Participants also experienced pressures to achieve competing body and appearance ideals (“thin” and “healthy”). In addition, they reported pressures to possess light skin, dark black hair, minimal body hair, and marry young, and noted these pressures negatively impacted their body esteem. Findings indicate that a combination of “traditional” and culturally-influenced factors are important to consider when conceptualizing eating pathology and body image in young SA American women.
Computer-Based Communication Tool Provides Effective Communication for Non-speaking Patients: A Quasi-experimental Study
Authors: Ertürk Yavuz Melek , Gürsoy Ayla
Published: August 2021

Even though they are conscious, patients who are unable to speak while connected to a mechanical ventilator have serious difficulties in communicating with healthcare staff. This research aimed to determine the effectiveness for patients of a computer-based communication tool (CBCT) and to compare these results with patients using a routine method. This quasi-experimental study was conducted with 90 intubated patients. It was found that 20.0% of the patients using CBCT stated that they had difficulties in communicating, while this rate was 82.2% among patients not using CBCT. Compared with participants in the control group, experimental group patients reported a lower median score for the anxiety levels (23.0 [20.0–39.0], 29.0 [20.0–57.00], p < .001) and higher mean comfort levels (130.2 ± 9.0, 109.6 ± 13.3, p < .001). Positive impacts of the CBCT are its suitability for patients who are dependent upon ventilation for different reasons and their improved ability to communicate effectively.
Genome-Wide Scan for Parent-of-Origin Effects in a sub-Saharan African Cohort With Nonsyndromic Cleft Lip and/or Cleft Palate (CL/P)
Authors: Gowans Lord J. J. , Comnick Carissa L. , Mossey Peter A. , Eshete Mekonen A. , Adeyemo Wasiu L. , Naicker Thirona , Awotoye Waheed A. , Petrin Aline , Adeleke Chinyere , Donkor Peter , Busch Tamara D. , James Olutayo , Ogunlewe Mobolanle O. , Li Mary , Olotu Joy , Hassan Mohaned , Adeniyan Oluwole A. , Obiri-Yeboah Solomon , Arthur Fareed K. N. , Agbenorku Pius , Oti Alexander A. , Olatosi Olubukola , Adamson Olawale O. , Fashina Azeez A. , Zeng Erliang , Marazita Mary L. , Adeyemo Adebowale A. , Murray Jeffrey C. , Butali Azeez
Published: August 2021

Objective

Nonsyndromic cleft lip and/or cleft palate (NSCL/P) have multifactorial etiology where genetic factors, gene–environment interactions, stochastic factors, gene–gene interactions, and parent-of-origin effects (POEs) play cardinal roles. POEs arise when the parental origin of alleles differentially impacts the phenotype of the offspring. The aim of this study was to identify POEs that can increase risk for NSCL/P in humans using a genome-wide dataset.

Methods

The samples (174 case-parent trios from Ghana, Ethiopia, and Nigeria) included in this study were from the African only genome wide association studies (GWAS) that was published in 2019. Genotyping of individual DNA using over 2 million multiethnic and African ancestry-specific single-nucleotide polymorphisms from the Illumina Multi-Ethnic Genotyping Array v2 15070954 A2 (genome build GRCh37/hg19) was done at the Center for Inherited Diseases Research. After quality control checks, PLINK was employed to carry out POE analysis employing the pooled subphenotypes of NSCL/P.

Results

We observed possible hints of POEs at a cluster of genes at a 1 mega base pair window at the major histocompatibility complex class 1 locus on chromosome 6, as well as at other loci encompassing candidate genes such as ASB18, ANKEF1, AGAP1, GABRD, HHAT, CCT7, DNMT3A, EPHA7, FOXO3, lncRNAs, microRNA, antisense RNAs, ZNRD1, ZFAT, and ZBTB16.

Conclusion

Findings from our study suggest that some loci may increase the risk for NSCL/P through POEs. Additional studies are required to confirm these suggestive loci in NSCL/P etiology.
Budesonide/Glycopyrrolate/Formoterol Fumarate Co-suspension Metered Dose Inhaler: A Triple Therapy for the Treatment of Chronic Obstructive Pulmonary Disease
Authors: Nigro Stefanie C. , Sobieraj Diana M.
Published: August 2021

Objective:

To review current evidence on the use of a fixed-dose combination (FDC) of budesonide/glycopyrrolate/formoterol fumarate (BGFF) triple therapy delivered via metered dose inhaler (MDI) in patients with chronic obstructive pulmonary disease (COPD) and offer clinical practice insights.

Data Sources:

We used PubMed to conduct the literature search from 1946 through June 30, 2021, using budesonide, glycopyrrolate or glycopyrronium, and formoterol.

Study Selection and Extraction:

We included clinical trials in patients with COPD along with pharmacokinetic or pharmacodynamic studies.

Data Synthesis:

In all, 19 citations were included. BGFF MDI reduces the risk of exacerbations regardless of exacerbation history compared with dual bronchodilators or inhaled corticosteroid/long-acting β-agonist. Rescue inhaler use decreased, and patient-reported outcomes of symptoms and well-being improved with triple therapy. Mortality was decreased with the higher-dose BGFF MDI in comparison to dual bronchodilator therapy. Dysphonia and candidiasis were more common with BGFF MDI compared with dual bronchodilators, as was pneumonia.

Relevance to Patient Care and Clinical Practice:

BGFF MDI is the second FDC triple therapy approved for COPD treatment. BGFF MDI improves important patient outcomes in COPD, including exacerbation risk. The unique co-suspension technology allows delivery of 3 active ingredients in 1 inhaler, a potential benefit to overcome adherence and technique-related barriers. These benefits must be gently weighed against the increased risk of pneumonia.

Conclusion:

The findings from phase 3 trials support the efficacy and safety of triple therapy in COPD. Future studies are needed to confirm potential mortality benefit and the role of triple therapy in patients without an exacerbation history.
Dolutegravir-Based Dual Therapies in HIV Pretreated Patients: A Real-Life Study in Madrid
Authors: Amor-García Miguel Ángel , Rodríguez-González Carmen Guadalupe , Chamorro-de-Vega Esther , Herranz-Alonso Ana , Sanjurjo-Sáez María
Published: August 2021

Background:

Few studies describe the use of dolutegravir (DTG)-based dual therapies under routine clinical practice.

Objectives:

To report real-life data on the use of DTG-based dual therapies in treatment-experienced patients.

Methods:

This was an observational, retrospective study. It included all treatment-experienced HIV patients starting a DTG-based dual therapy from 2014 to 2018. The primary end point was to identify the incidence and reasons for the switch. The secondary end points were to assess the effectiveness, safety, adherence, and costs after 48 weeks of treatment (W48).

Results:

The incidence of the switch to a DTG-based dual therapy increased from 1.6 patients per 1000 patient-years in 2014 to 38.6 in 2018. A total of 241 patients initiated this therapy: 113 (46.9%) patients started DTG plus rilpivirine (RPV), 72 (29.9%), DTG plus lamivudine (3TC), and 68 (28.2%), DTG plus boosted-darunavir (b-DRV). A total of 170 patients completed W48 of follow-up. By intention-to-treat analysis, 89.3% of virologically suppressed (VS) patients (94.3% with DTG plus b-DRV, 91.3% with DTG plus 3TC, and 87.2% with DTG plus RPV) and 56.7% of non-VS patients (71.4% with DTG plus RPV and 52.2% with DTG plus b-DRV) achieved a viral load <50 copies/mL at W48. The protocol-defined virological failure was 6.5%. Overall, 8.8% of patients had early discontinuation. The annual cost increased by €800 per patient ($916).

Conclusions and Relevance:

The use of DTG-based dual therapies has increased in real life, showing a favorable effectiveness and safety profile. Treatment costs increased, except for the switch to DTG plus 3TC.
Resource utilization prediction technique in cloud using knowledge based ensemble random forest with LSTM model
Authors: Valarmathi K , Kanaga Suba Raja S
Published: August 2021

Future computation of cloud datacenter resource usage is a provoking task due to dynamic and Business Critic workloads. Accurate prediction of cloud resource utilization through historical observation facilitates, effectively aligning the task with resources, estimating the capacity of a cloud server, applying intensive auto-scaling and controlling resource usage. As imprecise prediction of resources leads to either low or high provisioning of resources in the cloud. This paper focuses on solving this problem in a more proactive way. Most of the existing prediction models are based on a mono pattern of workload which is not suitable for handling peculiar workloads. The researchers address this problem by making use of a contemporary model to dynamically analyze the CPU utilization, so as to precisely estimate data center CPU utilization. The proposed design makes use of an Ensemble Random Forest-Long Short Term Memory based deep architectural models for resource estimation. This design preprocesses and trains data based on historical observation. The approach is analyzed by using a real cloud data set. The empirical interpretation depicts that the proposed design outperforms the previous approaches as it bears 30%–60% enhanced accuracy in resource utilization.
Load noise prediction of a power transformer
Authors: Lee Booyeong , Lee Kyuho , Park Chuljun , Ryu Seokwon , Chung Jintai
Published: August 2021

In this article, we propose a new regression equation to predict the noise of a power transformer based on the winding vibration under a loading condition. A regression between load noises and tank vibrations for multiple transformers with different rated powers was confirmed through measurements and regression analysis. A regression equation for load noise and winding vibration was derived considering the fact that the winding vibration level is proportional to the tank vibration level. The electromagnetic force, which is the excitation force of the winding, was obtained using the equivalent magnetic circuit network method to obtain the winding vibration required for the regression equation. Subsequently, the obtained force was applied to a finite element model for the winding to achieve the vibration response. The winding vibration obtained through these methods is closely correlated with the load noise, and the amount of winding vibration transferred to the tank could be changed according to the distance between the tank and the winding. Accordingly, an equation for predicting the load noise was established considering the winding vibration and the correlation factors according to the distance of the transmission path. The proposed prediction equation is considerably more accurate than the previous prediction equation.
Event-triggered adaptive neural network backstepping sliding mode control of fractional-order multi-agent systems with input delay
Authors: Chen Tao , Yuan Jiaxin , Yang Hui
Published: August 2021

This article investigates the consensus problem for a class of fractional-order multi-agent systems with input delay. Each follower is modeled as a system with input delay and nonlinear dynamics. To avoid “explosion of complexity” and obtain fractional derivatives for virtual control functions continuously, dynamic surface control technology is introduced into an adaptive neural network backstepping controller. A dynamic event-triggered scheme without Zeno behavior is considered, which can reduce the utilization of communication resources. The sliding mode control technology is introduced to enhance robustness. The Pade delay approximation method is extended to fractional-order systems, which converts the original systems into systems without input delay. The stability of systems is ensured by the constructed Lyapunov functions. Examples and simulation results show that the consensus tracking errors can quickly converge and all the followers can synchronize to the leader by the proposed method.
Experimental identification of the material standard linear solid model parameters by means of dynamical measurements
Authors: Amadori Stefano , Catania Giuseppe
Published: August 2021

A procedure for the experimental identification of the material standard linear solid model parameters by means of dynamic mechanical analysis test instrument measurements is presented. Since the standard linear solid material stress–strain functional D( ω) relationship in the frequency domain formally depends on the standard linear solid material parameters, a procedure able to identify these parameters from test measurement estimates is proposed in this work. Nevertheless, a critical, nonlinear and non-parametric approach is to be followed since the number of the material standard linear solid block components is generally unknown, and the material D( ω) shows a highly nonlinear dependency on the unknown standard linear solid material parameters. For these reasons, measurement and test model noise is expected to strongly influence the accuracy of the identification results. A multi-step procedure is presented, consisting first in the non-parametric identification of a frequency dependent, two degrees of freedom model instrument frame by means of a polynomial rational function, where polynomial order and parameters, such as polynomial coefficients and pole-residue couples, are optimally identified by means of an algebraic numerical technique and of an iterative stabilization procedure. Another procedure able to identify the material D( ω) polynomial rational functional relationship in the frequency domain is also proposed, taking into account the dynamic contribution of the instrument frame, of the inertial contribution of the distributed mass of the beam and of the lumped mass of the instrument force measuring system. An effective procedure, able to identify the standard linear solid material model parameters in the time domain from the identified material physical poles, is finally proposed. Some application examples, concerning the identification of the standard linear solid model of a known material and of an unknown composite material, are shown and discussed as well.
Experimental and numerical investigation of damping in a hybrid automotive damper combining viscous and multiple-impact mechanisms
Authors: Badri Yousif , Sassi Sadok , Hussein Mohammed , Renno Jamil
Published: August 2021

One of the least investigated approaches in passive vibration control is the possibility of combining different types of dampers that use different damping principles. Such a combination process, if wisely designed and implemented, has the potential to increase the damping performance and extend the damper’s application. The primary purpose of this work is to experimentally and numerically investigate the damping behavior of a novel Fluid-Impact Hybrid Damper. This damper combines a conventional Viscous Fluid Damper with a Particle-Impact Damper. The Fluid-Impact Hybrid Damper comprises a 3D-printed plastic box attached to the Viscous Fluid Damper’s moving rod and filled with stainless steel balls. An experimental setup was designed to drive the Viscous Fluid Damper’s rod into harmonic oscillations at different frequencies (1, 2, 4, 6, and 8 Hz). The number of balls was changed three times (5, 10, and 15) to assess the effect of this parameter on the damping performance of the Fluid-Impact Hybrid Damper. A finite element model of the Fluid-Impact Hybrid Damper was developed using LS-Dyna explicit simulation program. The objective of the FE model is to investigate the elastoplastic balls-box collisions using a piecewise-linear plasticity material model. For both the experimental and numerical results, the Frequency Response Function was considered as the main comparison component for a set of force-independent results. The measured Frequency Response Functions showed a noticeable reduction in amplitude at the system’s natural frequency (2 Hz), with an acceptable accuracy between the two approaches.
Parameters optimization of dynamic vibration absorber based on grounded stiffness, inerter, and amplifying mechanism
Authors: Sui Peng , Shen Yongjun , Yang Shaopu , Wang Junfeng
Published: August 2021

In the field of dynamics and control, some typical vibration devices, including grounded stiffness, inerter and amplifying mechanism, have good vibration isolation and reduction effects, especially in dynamic vibration absorber (DVA). However, most of the current research studies only focus on the performance of a single device on the system, and those DVAs are gradually becoming difficult to meet the growth of performance demand for vibration control. On the basis of Voigt dynamic vibration absorber, a novel dynamic vibration absorber model based on the combined structure of grounded stiffness, inerter, and amplifying mechanism is presented, and the analytical solution of the optimal design formula is derived. First, the motion differential equation of the system is established, and the normalized amplitude amplification factor of the displacement is calculated. It is found that the system has three fixed points unrelated to the damping ratio. The optimal frequency ratio is obtained based on the fixed-point theory. In order to ensure the stability of the system, it is found that inappropriate inerter coefficient will cause the system instable when screening optimal grounded stiffness ratio. Accordingly, the best working range of inerter is determined. Finally, optimal grounded stiffness ratio and approximate optimal damping ratio are also obtained. The influence of inerter coefficient and magnification ratio on the response of the primary system is analyzed. The correctness of the derived analytical solution is verified by numerical simulation. Compared with other dynamic vibration absorbers, it is verified that presented model has superior vibration absorption performance and provides a theoretical basis for the design of a new type of dynamic vibration absorbers.
A Decolonial Approach to the Discipline of Journalism Theory in Brazil
Authors: Daros Otávio
Published: August 2021

Although Brazil has its tradition of journalistic thinking, this essay shows that the discipline of journalism theory has, in this country, an intellectual nucleus based in the United States and Europe. It is true that both academic cultures provide foundations, but they do not claim to provide explanations about the society in which Brazilian journalism developed. This argument is corroborated by the analysis of the bibliographic references used by Brazilian courses. Considering that the impetus for the de-Westernization must come from scholars in emerging countries, this essay argues that the curriculum could be a key element to incite this transformation.
Perioperative and Anesthetic Considerations in Tetralogy of Fallot With Pulmonary Atresia
Authors: Quinlan Casey A. , Latham Gregory J. , Joffe Denise , Ross Faith J.
Published: August 2021

Tetralogy of Fallot with pulmonary atresia (ToF-PA) is a rare diagnosis that includes an extraordinarily heterogeneous group of complex anatomical findings with significant implications for physiology and prognosis. In addition to the classic findings of ToF, this particular diagnosis is characterized by complete failure of forward flow from the right ventricle to the pulmonary arterial system. As such, pulmonary blood flow is entirely dependent on shunting from the systemic circulation, most frequently via a patent ductus arteriosus, major aortopulmonary collaterals, or a combination of the two. The pathophysiology of ToF-PA is largely attributable to the abnormalities of the pulmonary vasculature. Ultimately, these patients require operative intervention to create a reliable, controlled source of pulmonary blood flow and ideally complete intracardiac repair. Even after operative correction, these patients remain at risk for pulmonary arterial stenoses and pulmonary hypertension. Although there have been significant advances in surgical and interventional management of ToF-PA leading to dramatic improvements in survival and long-term functional status, there is ongoing debate about the optimal management strategy given the risk of development of irreversible abnormalities of the pulmonary vasculature and the morbidity and mortality associated with sometimes multiple, complex operative interventions often occurring early in infancy. This review will discuss the findings in patients with ToF-PA with a focus on the perioperative and anesthetic management and will highlight challenges faced by the anesthesiologist in caring for these patients.
Effect of light backscattering from anterior segment structures on automated flare meter measurements
Authors: Hasanreisoglu Murat , Kesim Cem , Yalinbas Duygu , Yilmaz Mervenur , Uzunay Nur Sena , Aktas Zeynep , Halim Muhammad Sohail , Sepah Yasir J , Nguyen Quan Dong , Sahin Afsun
Published: August 2021

Background:

To evaluate effect of maximal anterior cortical lens density, iris scatter and anterior chamber depth on laser flare photometry.

Methods:

Patients diagnosed with clinical uveitis were enrolled in the study. Clinical flare gradings were recorded upon the Standardization of Uveitis Nomenclature. Aqueous flare was measured with an automated device (Kowa FM-700). Back-scattering from anterior cortical lens and anterior iris surface was calculated from Scheimpflug images. A curvilinear regression model was used to calculate estimated values for each clinical grade. These values were used to split cases in Group I (laser flare photometry lower than estimated) and Group II (laser flare photometry higher than estimated). Mean anterior chamber depth, pupil aperture, maximal anterior cortical lens density and iris scatter values were compared between two groups. A stepwise multiple regression analysis was performed to determine the effect of clinical flare gradings and ocular parameters on aqueous flare measurements.

Results:

The study included 228 eyes of 114 cases. Scheimpflug images were obtained from 105 eyes. Estimated aqueous flare measurements (in photons/milliseconds) were 4.87, 8.50, 14.81, 25.83, 45.04 and 136.93 for 0, 0.5+, 1+, 1.5+, 2+ and 3+ clinical flare respectively. Group II had higher maximal anterior cortical lens density than Group I (96.6 ± 37.1 vs 77.9 ± 17.1 pixel unit, p = 0.001). The measured aqueous flare was significantly related to clinical flare, maximal anterior cortical lens density and pupil aperture (adjusted R2: 0.480, p < 0.001).

Conclusion:

The back-scattered light from anterior cortical lens could affect laser flare photometry measurements. This effect might be quantified by Scheimpflug imaging.
Orthogonal tests of the lubricating performance of SnO2 nanoparticles in poly-alfa-olefine oil
Authors: Wang Bing-Xu , Wu Fan , Zhang Xiuming , Yuan Yongfeng , Guo Shaoyi , Barber Gary C
Published: August 2021

The tribological properties of SnO2 nanofluids were investigated using ball-on-plate reciprocating sliding wear tests. It was found that the coefficient of friction was reduced by 34.9% using 3 wt% SnO2 nanoparticles. The wear width and wear depth were reduced by 42% and 50.1%, respectively, using 2 wt% SnO2 nanoparticles. In the orthogonal tests, the frequency had the greatest influence on the friction and wear loss. Additionally, the optimal working conditions were a normal load of 50 N, a motion frequency of 1 Hz, and a surface roughness of 500–600 nm. Additionally, the excellent tribological performance of SnO2 nanofluids could be attributed to the formation of a tribo-film with a low shearing resistance due to the oleic acid and a protective layer due to the embedment of SnO2 nanoparticles.
Intensification, discovery and abandonment: Unearthing global ecologies of dis/connection in pandemic times
Authors: Treré Emiliano
Published: August 2021

This article explores how people have reconfigured their dis/connective repertoires during COVID-19 pandemic-related lockdowns. Relying on a media ecology approach and on 45 interviews carried out in different parts of the world, it tackles two limitations of the digital disconnection literature, namely social media reductionism and universalism, advancing a theoretical and empirical contribution. Firstly, it explores and unfolds dis/connective practices in relation to an intricate multiplicity of old and new practices, technologies, platforms and formats, foregrounding three key dynamics in the reconfiguration of dis/connective repertoires: intensification, (re)discovery and abandonment. Then, it critically drills down into the uneven power relations, divides and inequalities that traverse these three dynamics. This article demonstrates that dis/connective practices are carried out across variable configurations of devices, formats and platforms and shaped by privileges and imbalances that are particularly severe in the context of the Global South. In doing so, this article complexifies taken-for-granted assumptions regarding the meanings of dis/connection, establishing a dialogue with digital inequality and labour studies, hence unfolding new horizons of inquiry for digital disconnection studies.
Decently transgressing: expressions of female heterosexuality and the discourses of (hetero)sexual pleasure in South Africa
Authors: Smuts Letitia
Published: August 2021

This article explores sexual agency and pleasure among heterosexual women in South Africa. By focussing on Tupperware-style sex-toy parties, this article offers a glimpse into a ‘hidden’ world of white, middle-class women living in Johannesburg. What is revealed in this ethnographic account is that these gatherings promise women new ways of enjoying sex, while remaining within the boundaries of heteronormative notions of (hetero)sex. I use the term ‘decently transgressing’ to capture the ways in which the women in this study make sense of their (hetero)sexual selves and how they negotiate their (hetero)sexual agencies, particularly in relation to past and present heteronormative discourses within the South African context. The findings show that there are tensions between women wanting to embrace their own sexual agency and desires, yet at the same time being limited by certain heteronormative norms.
An investigation of the structural nonlinearity effects on the building seismic risk assessment under mainshock–aftershock sequences in Tehran metro city
Authors: Khansefid Ali
Published: August 2021

This research attempts to investigate the effects of neglecting the nonlinear behavior of structures on the estimated seismic risk assessment of buildings under mainshock–aftershock (MA) sequences. In this regard, the Tehran metro city is selected as a building site due to its high seismicity level. Three separate 5-, 10-, and 15-story buildings are considered and designed based on international design codes. The earthquake hazard scenarios containing mainshock–aftershock sequences are modeled randomly using a synthetic stochastic methodology for this region. Next, by implementing the Monte Carlo simulation method, buildings performances are obtained for a large number of different scenarios, and consequently, the lifetime direct losses imposed on the buildings are evaluated. To investigate the effect of structural nonlinearity, the described process is performed in two distinct scenarios: one of them assumes that the buildings behave linearly, while the other one allows the structures to respond nonlinearly. Finally, the level of dependency of calculated lifetime seismic risk to this parameter and also the contribution of different sources of losses, including physical damage, business interruption, and casualty losses, are investigated considering the aftershocks effect.
Patient engagement with digital disease management and readmission rates: The case of congestive heart failure
Authors: Gjeka Rudin , Patel Kirit , Reddy Chandra , Zetsche Nora
Published: August 2021

Congestive heart failure (CHF) is one of the most common diagnoses in the elderly United States Medicare (⩾ age 65) population. This patient population has a particularly high readmission rate, with one estimate of the 6-month readmission rate topping 40%. The rapid rise of mobile health (mHealth) presents a promising new pathway for reducing hospital readmissions of CHF, and, more generally, the management of chronic conditions. Using a randomized research design and a multivariate regression model, we evaluated the effectiveness of a hybrid mHealth model—the integration of remote patient monitoring with an applied health technology and digital disease management platform—on 45-day hospital readmissions for patients diagnosed with CHF. We find a 78% decrease in the likelihood of CHF hospital readmission for patients who were assigned to the digital disease management platform as compared to patients assigned to control.