Feedback Mode Research Articles

Review on the Rotating Detonation Engine and It’s Typical Problems

Abstract Detonation is a promising combustion mode to improve engine performance, increase combustion efficiency, reduce emissions, and enhance thermal cycle efficiency. Over the last decade, significant progress has been made towards the applications of detonation mode in engines, such as standing detonation engine (SDE), Pulse detonation engine (PDE) and rotating detonation engine (RDE), and the understanding of the fundamental chemistry and physics processes in detonation engines via experimental and numerical studies. This article is to provide a comprehensive overview of the progress in the knowledge of rotating detonation engine from the different countries. New observations of injection, ignition, and geometry of combustor, pressure feedback, and combustion modes of RDE have been reported. These findings and advances have provided new opportunities in the development of rotating detonation for practical applications. Finally, we point out the current gaps in knowledge to indicate which areas future research should be directed at.

Development of intellectual abilities and physical fitness of middle school students by means of football

The purpose of the work is to scientifically substantiate the existence of a positive relationship between the physical and intellectual development of young players of 12-13 years. The formative experiment was conducted on the basis of PSS # 38, in fifth grades. The use of section football lessons has a stimulating effect on the functional state of students and the activation of the sympathetic division of the autonomic nervous system, as evidenced by the increase in the speed of complex reaction and the decrease in the time of minimal signal exposure in the test to determine the speed of complex reaction in the feedback mode.

(Invited) A Real Time Platform for Observing Surface Processes at Activated Battery Cathodes:Resolving CO2 and O2 Evolution

Understanding the impact of surface catalysis on the interfacial evolution of battery electrodes during energy storage is key to developing reliable, efficient, and safe high-energy density technologies. The formation of interphases is essential for the operation at anodes, where the solid-electrolyte interphase (SEI) kinetically stabilizes the electrode; recently, the formation of interfacial structures at high-energy density cathodes has also garnered great interest due to the kinetic and Coulombic limitations it places on the performance of various promising materials. [1] Elucidating how electrode surface structure, composition, and potential-dependent behavior impact the degradation reactions of the electrolyte and solvent is a fundamental pursuit with significant practical implications, as it may be key to engineering safe devices and to improve the efficiency of growing and aging stable interfaces at an industrial scale. Thus, understanding how surface reactions prompt the evolution of interfaces is a pressing challenge. While X-ray and mass-spectrometric methods [2,3] have been used to characterize these chemistries, probing the surface chemistry of these electrodes with higher versatility, in situ and with high spatiotemporal and chemical resolution represents a formidable analytical challenge.Here, we present an analytical methodology based on the use of scanning electrochemical microscopy in various modes for quantitatively detecting the formation, in real time and with high spatial resolution, of gaseous by-products such as O2 and CO2 from the catalytic decomposition of the electrolyte/solvent at battery electrodes. Using the generation/collection mode we developed an analytical platform capable of resolving these two species in order to quantify material degradation processes as a function of state of charge, and by using the feedback mode we can simultaneously monitor their impact on the interfacial kinetics of the electrode. By insightfully using ultramicroelectrode methods, and principles of CO2 electroreduction, we evaluated the nonaqueous reaction mechanisms involved in the detection to provide quantitative guidance on the relationship between the detected signal and the quantification of the processes undergoing at the battery electrode. We tested the response of our probes on a model NMC cathode, confirming O2 and CO2 evolution processes under conditions reported to exhibit bulk decomposition and surface passivation, respectively. This work creates a foundation not only for the high spatiotemporal evolution of interfacial processes at battery electrodes, but also for the understanding of CO2-related mechanisms in nonaqueous solvents.[1] Li, W. et al. Nature Comm. 2017, 8, 14589[2] Li, Q. et al. ACS Appl. Mater. Interfaces 2020, 12, 2, 2319–2326[3] McCloskey, B.D. et al. J. Phys. Chem. Lett. 2012, 3, 997-1001

Characterization of Inherently Chiral Electrosynthesized Oligomeric Films by Voltammetry and Scanning Electrochemical Microscopy (SECM).

A voltammetric and scanning electrochemical microscopy (SECM) investigation was performed on an inherently chiral oligomer-coated gold electrode to establish its general properties (i.e., conductivity and topography), as well as its ability to discriminate chiral electroactive probe molecules. The electroactive monomer (S)-2,2′-bis(2,2′-bithiophene-5-yl)-3,3′-bibenzothiophene ((S)-BT2T4) was employed as reagent to electrodeposit, by cyclic voltammetry, the inherently chiral oligomer film of (S)-BT2T4 (oligo-(S)-BT2T4) onto the Au electrode surface (resulting in oligo-(S)-BT2T4-Au). SECM measurements, performed in either feedback or competition mode, using the redox mediators [Fe(CN)6]4− and [Fe(CN)6]3− in aqueous solutions, and ferrocene (Fc), (S)-FcEA, (R)-FcEA and rac-FcEA (FcEA is N,N-dimethyl-1-ferrocenylethylamine) in CH3CN solutions, indicated that the oligomer film, as produced, was uncharged. The use of [Fe(CN)6]3− allowed establishing that the oligomer film behaved as a porous insulating membrane, presenting a rather rough surface. This was inferred from both the approach curves and linear and bidimensional SECM scans, which displayed negative feedback effects. The oligomer film acquired semiconducting or fully conducting properties when the Au electrode was biased at potential more positive than 0.6 V vs. Ag|AgCl|KCl. Under the latter conditions, the approach curves displayed positive feedback effects. SECM measurements, performed in competition mode, allowed verifying the discriminating ability of the oligo-(S)-BT2T4 film towards the (S)-FcEA and (R)-FcEA redox mediators, which confirmed the results obtained by cyclic voltammetry. SECM linear scans indicated that the enantiomeric discriminating ability of the oligo-(S)-BT2T4 was even across its entire surface.

Number of Pixel Change Rate and Unified Average Changing Intensity for Sensitivity Analysis of Encrypted inSAR Interferogram

The transmission of images from satellites to earth is on the brink of many threats which can affect the confidentiality of the data as well as its quality. Several encryption algorithms are used to secure the transmitted images. The objective in this work is to analyze the sensitivity of a particular type of satellite image, which is an interferogram from interferometric imaging systems inSAR system. This image is encrypted by cryptosystem based on the Advanced Encryption Standard with key length of 256 bits (AES-256) standard and the asymmetric Rivest, Shamir & Adelman (RSA) encryption algorithm using Counter-mode encryption (CTR) mode and Output FeedBack (OFB) mode. The analysis made in this paper is carried out on two types of sensitivity. The first analysis is the sensitivity to change of a pixel in the original interferogram and the second is the sensitivity to the key. Two parameters are used to assess sensitivity: The Number of Pixel Change Rate (NPCR) and the Unified Average Changing Intensity (UACI). The obtained results show that the two modes AES-256-OFB and AES-256-CTR are favorable but cannot be implemented on board a satellite without providing a mechanism capable of compensating for the low resistance to error propagation. Metrics on the clear and encrypted interferogram are exploited such as the Structural Similarity Index (SSIM), Gradient-based Structural Similarity (GSSIM), The use of these metrics, allowed us to see that a change of one pixel in the interferogram and the change of the encryption key will affect the quality of the interferogram, as well as a statistical histogram analysis.

Collaborative Tabletops for Blind People

Interactive tabletops offer unique collaborative features, particularly their size, geometry, orientation and, more importantly, the ability to support multi-user interaction. Although previous efforts were made to make interactive tabletops accessible to blind people, the potential to use them in collaborative activities remains unexplored. In this paper, we present the design and implementation of a multi-user auditory display for interactive tabletops, supporting three feedback modes that vary on how much information about the partners' actions is conveyed. We conducted a user study with ten blind people to assess the effect of feedback modes on workspace awareness and task performance. Furthermore, we analyze the type of awareness information exchanged and the emergent collaboration strategies. Finally, we provide implications for the design of future tabletop collaborative tools for blind users.

Tuning the Reactivity of Electrolyte Solvents on Lithium Metal by Vinylene Carbonate

Organic solvents undergo degradation reactions when in contact with lithium metal. These reactions form a layer of decomposition products that partly prevents further electrolyte decomposition—passivation. Still, the chemical processes in this system are complex and have not yet been fully understood though it is of high relevance for lithium metal batteries. Scanning Electrochemical Microscopy (SECM) in feedback mode as well as GC-MS are used for analyzing the interface as well as soluble decomposition products. SECM data show that the native interface thickness on metallic lithium from ethylene carbonate (EC) and ethyl methyl carbonate (EMC) electrolyte solutions is reduced by approx. 98% by adding 5 wt% vinylene carbonate (VC) to the solution. The addition of VC changed significantly the dynamics of the growth of the deposition layer. GC-MS studies of the EC:EMC electrolyte solution proof an ongoing reaction of the metallic lithium with the electrolyte even after several days. In comparison, the addition of VC appears to stabilize the interface and no decomposition products could be identified. It is concluded that the addition of VC to the electrolyte solution from EC:EMC prevents the trans-esterification of EMC by surface passivation and not by scavenging alkoxides as claimed in literature.

Contextualized Grammar in EFL Students’ Writings: A Case for Corrective Feedback

ABSTRACT T he current study aimed at empirically exploring the effectiveness of the direct versus indirect modes of corrective feedback in developing grammatical accuracy in writing among the EFL majors at the Faculty of Education, Al-Azhar University. The participants of the study (totaling 50) were randomly assigned from the first year EFL students at the Faculty of Education of Al-Azhar University in Cairo and categorized into two experimental groups studying a program designed for contextualizing grammar in writing. To assess the findings of that program and fulfill the purposes of the study, a writing test and its analytic scoring rubric was developed. The results of the study consistently demonstrated that both direct and indirect modes of feedback had high effectiveness in developing grammatical accuracy in writing as the participants who received direct or indirect corrective feedback showed better performance in the post-test than that of the pre-test. The study ended with discussing the findings reached, presenting recommendations, and suggesting some issues for further research.

A Fast Response and CMOS Compatible Micro Gas Flow Sensor With Thermal Feedback

This letter presents a CMOS compatible micro flow sensor (MFS) that operates in a thermal feedback (TF) mode. The proposed MFS contains four parallel polysilicon resistors on the micro bridges. The gas flow induced temperature difference between two outlying thermistors is minimized and balanced through the negative thermal feedback, while the power distribution on two inlying microheaters is automatically adjusted. Accordingly, the measured voltage difference between two inlying microheaters is used as the sensor output signal. For the N2 gas flow, the proposed MFS works in TF mode achieve a prominent sensitivity of 1.74V/(m/s) and a bidirectional detection range of −6 ∼ 6 m/s, which shows an almost 2X enhanced flow range as compared to the counterpart works in a constant voltage mode. Moreover, the rise time of MFS under a suddenly generated gas flow is experimentally determined as 3.1 ms (error ±0.13 ms). The measured rise time is 43% faster than that of the micro flow sensor without thermal feedback, which proves the successful development of a fast response MFS.

Written corrective feedback across different levels of EFL students’ academic writing proficiency: Outcomes and implications

This current research aimed at finding out the impact of different feedback modes, that is indirect corrective feedback and direct corrective feedback, on the writing proficiency of EFL students at the university level. Direct and indirect corrective feedbacks were provided by covering global and local aspects of writing together. This study reported on a 14-week study with 63 students majoring in the English Education Department of an outstanding university in Surabaya, Indonesia. The pre-test was given to 35 students that belonged to a high proficiency level group, whereas 28 students belonged to the low proficiency level. The proficiency level was used to examine whether the corrective feedback was effective for certain levels of learners’ proficiency. An experimental design was run to examine whether there was a noteworthy different impact of direct corrective feedback (DCF) and indirect corrective feedback (ICF) on descriptive essays produced by EFL students. Two groups of participants, DCF group and ICF group, wrote eight topics in which each was treated using different feedback. The results revealed that the DCF is more powerful than ICF and contributes significantly to improve students’ EFL writing, regardless of the students’ level of proficiency (high or low). The outcomes of DCF and ICF in the EFL writing process that do not depend on proficiency level indicates that the use of DCF and ICF is not influenced by proficiency level. In other words, direct corrective feedback is advantageous for both low and high proficiency learners in EFL writing process.

Second language writing instructors’ feedback practice in response to automated writing evaluation: A sociocultural perspective

While automated writing evaluation (AWE) programs are becoming a readily available pedagogic option for second language (L2) writing instructors, the important question of whether the use of AWE would impact teacher feedback remains largely unexplored. This study investigated teacher feedback practices in response to the adoption of AWE in a mainstream L2 curriculum in China. Informed by the mediated learning experience (MLE) theory and drawing upon semi-structured interviews, responses to a questionnaire, classroom observations, and AWE records, this study observed that the impact of AWE was manifested in changes not only in feedback mode, amount, types and levels, but also in the intentionality, reciprocity, transcendence, and meaning dimensions of teacher feedback. The findings also show that such impact was further mediated by individual teacher beliefs about AWE and students, teacher willingness to offer scaffolding and contextual factors. This study suggests that with teacher and contextual supports, AWE systems can be taken as important sociocultural artifacts mediating the integration of MLE as a new object of teacher feedback activity in writing classrooms. These findings call for attention to how more transformative teacher feedback can be promoted with the use of AWE.

Ejective and preventative: the IllustrisTNG black hole feedback and its effects on the thermodynamics of the gas within and around galaxies

ABSTRACT Supermassive black holes (SMBHs) that reside at the centres of galaxies can inject vast amounts of energy into the surrounding gas and are thought to be a viable mechanism to quench star formation in massive galaxies. Here, we study the $10^{9-12.5}\, \mathrm{M_\odot }$ stellar mass central galaxy population of the IllustrisTNG simulation, specifically the TNG100 and TNG300 volumes at z = 0, and show how the three components – SMBH, galaxy, and circumgalactic medium (CGM) – are interconnected in their evolution. We find that gas entropy is a sensitive diagnostic of feedback injection. In particular, we demonstrate how the onset of the low-accretion black hole (BH) feedback mode, realized in the IllustrisTNG model as a kinetic, BH-driven wind, leads not only to star formation quenching at stellar masses $\gtrsim 10^{10.5}\, \mathrm{M_\odot }$ but also to a change in thermodynamic properties of the (non-star-forming) gas, both within the galaxy and beyond. The IllustrisTNG kinetic feedback from SMBHs increases the average gas entropy, within the galaxy and in the CGM, lengthening typical gas cooling times from $10\!-\!100\, \mathrm{Myr}$ to $1\!-\!10\, \mathrm{Gyr}$, effectively ceasing ongoing star formation and inhibiting radiative cooling and future gas accretion. In practice, the same active galactic nucleus (AGN) feedback channel is simultaneously ‘ejective’ and ‘preventative’ and leaves an imprint on the temperature, density, entropy, and cooling times also in the outer reaches of the gas halo, up to distances of several hundred kiloparsecs. In the IllustrisTNG model, a long-lasting quenching state can occur for a heterogeneous CGM, whereby the hot and dilute CGM gas of quiescent galaxies contains regions of low-entropy gas with short cooling times.

International Legal and Philosophical Aspects of the New Protection Concept of the Common Heritage of Mankind

The article is devoted to the systematize the characteristics of objects of the common heritage of mankind, to study the historical origins and connections of the concept of the common heritage of mankind with other legal categories and worldview systems, to determine the prospects of application of the concept in its legal and worldview aspects. The work is based on a set of approaches united in sociological legal consciousness, primarily historical, communicative and psychological ones, and on the methodological basis of I. Kant’s philosophy. The concept of the common heritage of mankind in the context of trans-historical development of social consciousness as an important system-making factor of societies of macro-level scales for the first time is investigated in the research. Mankind should return to its social consciousness an intersubjective relation to its planetary natural environment, that is, its inclusion in its multilevel diversity and recognition of its “subjectivity”, if not in a legal sense, then in the awareness of its complexity, self-regulatory properties, the need for its constant cognition in feedback mode – this idea should be the main new concept of protection of the common heritage of mankind.

Trajectory Tracking of Nonlinear Unmanned Rotorcraft Based on Polytopic Modeling and State Feedback Control

Trajectory tracking is extremely difficult for rotorcrafts based on the nonlinear model and taking into account all the parameters of the system and especially considering the effects of flapping and the main rotor and its control tail in all directions. This paper describes the tracking route, based on nonlinear model and velocity control and feedback mode and Polytopic linear parameter varying (LPV) modeling with the help of solving linear matrix inequalities (LMI) equations for different conditions and complex maneuvers for an unmanned rotorcraft that has been examined in all directions including, longitudinal, altitudinal, latitudinal directions. Based on the different operating points of the system and the different flight conditions, first a Polytopic modeling of the system is performed, and then the control signal is generated based on the state feedback and solution of the linear matrix inequalities (LMI) equations. The final control signal consists of feedback of changes of the state variables around the nominal trajectory under the designed feedback gains, in addition to the nominal control signal for the desired trajectory. In calculating the nominal control signal for the optimum trajectory, the Polytopic system model is used instead of the nonlinear system model. Therefore, the final control signal does not require a dynamic system model and all control calculations are performed using a Polytopic system model and have high computational speed. System simulation shows the capabilities of the proposed control system in different operating conditions.

Inhibitory effect of sinomenine on lung cancer cells via negative regulation of α7 nicotinic acetylcholine receptor.

Lung cancer is the leading cause of cancer deaths worldwide, with a high morbidity and less than 20% survival rate. Therefore, new treatment strategies and drugs are needed to reduce the mortality of patients with lung cancer. α7 nicotinic acetylcholine receptor (α7 nAChR), as a receptor of nicotine and its metabolites, is a potential target for lung cancer treatment. Our previous studies revealed that sinomenine plays anti-inflammation roles via α7 nAChR and down-regulates the expression of this receptor, thus increasing the inflammatory response. Hence, sinomenine is possibly a natural ligand of this receptor. In the present study, the effects of sinomenine on lung cancer A549 cells and tumor-bearing mice were determined to investigate whether this alkaloid has an inhibitory effect on lung cancer via α7 nAChR. CCK-8 assay, wound-healing test, and flow cytometry were performed for cell proliferation, cell migration, and apoptosis analysis in vitro, respectively. Xenograft mice were used to evaluate the effects of sinomenine in vivo. Results showed that sinomenine decreased cell proliferation and migration abilities but increased the percentage of apoptotic cells. Tumor volume in tumor-bearing mice was significantly reduced after sinomenine treatment compared with that in the vehicle group mice (p<0.05). Furthermore, the effects of sinomenine were abolished by the α7 nAChR antagonist mecamylamine and the allosteric modulator PNU-120596, but no change occurred when the mice were pretreated with the muscarinic acetylcholine receptor antagonist atropine. Meanwhile, sinomenine suppressed α7 nAChR expression in vitro and in vivo, as well as the related signaling molecules pERK1/2 and ERK1/2 and the transcription factors TTF-1 and SP-1. By contrast, sinomenine up-regulated the expression of another transcription factor, Egr-1. These effects were restricted by mecamylamine and PNU but not by atropine. Results suggested that sinomenine can inhibit lung cancer via α7 nAChR in a negative feedback mode.

Zero-consumption Clark-type microsensor for oxygen monitoring in cell culture and organ-on-chip systems

Clark-type oxygen microsensors promise zero analyte consumption if the feedback mode (Ross principle) is successfully implemented. Our approach was a microsensor with platinum as working and counter electrode material, a pHEMA hydrogel layer containing buffer solution as electrolyte and PDMS as gas-permeable membrane. We were able to demonstrate successful implementation of the Ross principle by measurement of the counter electrode potential. The microsensors could be stored dry and activated by immersion into aqueous analyte. Chronoamperometric protocols were applied to enable long-term stability for more than one week without recalibration. The microsensors were integrated in conventional tissue culture flasks for cell measurements. Respiration monitoring was done in T-47D breast cancer monolayer culture. The unique feature combination of zero analyte consumption, 1-point calibration and sufficient long-term stability make these sensors an ideal candidate to monitor oxygenation and respiration in different cell culture and organ-on-chip systems.

A scanning electrochemical microscopy characterization of the localized corrosion reactions occurring on nitinol in saline solution after anodic polarization

Scanning electrochemical microscopy (SECM) in a combined amperometric/potentiometric operation was used to characterize the electrochemical activity of nitinol, before and after anodic treatment, in 0.1 M NaCl solution. The SECM operation in the feedback mode showed that the nitinol surface was homogeneously passive after surface finishing and storage under ambient conditions, while heterogeneous surface characteristics occurred after application of anodic polarization, even for a limited time. That is, the development of anodic and cathodic sites has been detected due to the onset of localized corrosion processes on the metal surface. The evolution of hydrogen gas from localized sites was monitored using SECM in the substrate generation/tip collection mode (SG/TC), while SECM operated in potentiometric mode was used to map the pH distribution in the electrolyte volume adjacent to the nitinol surface. Local acidification was observed around anodic spots associated with the Ni2+ discharge, as well as alkalinization above the cathodic zones.

Electrochemical Investigation of Redox Processes of Labile Cu(II)/Cu(I)-Cl Complexes by Scanning Electrochemical Microscopy.

The studies reported here provide detailed information on the kinetics and reaction mechanism determined by the scanning electrochemical microscopy (SECM) for Cu(II)/Cu(I) redox reactions in a system with excess chloride. In positive feedback mode, the tip voltammograms obtained consist of two partially overlapping reduction waves, not one quasi-reversible process as was always thought. The reduced species of CuIICl42- and [CuIICl3(H2O)]- could coexist during the time scale of SECM measurements, due to the slowness of the ligand substitution reaction of [CuIICl3(H2O)]- to CuIICl42-. The stepwise EC reactions of CuIICl42- have experienced the same electron transfer kinetics as do outer-sphere reactants, while the reactions of [CuIICl3(H2O)]- followed concerted EC pathways and much lower rate constants can be obtained, mainly due to the nonadiabatic character of electron transfer (k0Pt/k0Au = 1.625). The findings of this study can offer valuable insights for analyzing the electrode kinetics of labile complexes of metals in aqueous solutions.

The Use of a Damping System in a Synchrotron for the Short-Time Excitation of Coherent Oscillations of Particles

The possibility of applying a damping system of coherent transverse beam oscillations in a synchrotron using a positive feedback mode for the short-time excitation of coherent particle oscillations is discussed. Examples of excitation modes for the parameters of the LHC Damper system are presented.

An E-Survey of Current Voice Therapy Practices Amongst Speech Language Pathologists (SLPs) in India.

In India, Speech Language Pathologists (SLPs) generally work with ENT surgeons and use a variety of treatment approaches, service delivery methods, feedback modes, and outcome measures in clinical practice while dealing with voice disorders. The practice preferences of the SLPs are based on theoretical and practical exposure during their graduate course, guidance from professional bodies, evidence-based practices, etc. The facilities in the work setting also determine the practice style of the SLP. This study reports information on demographics of the SLPs, nature of patients served, intervention methods, and evidence-based practices followed by the SLPs via an E-survey. Analysis of the survey from 55 SLPs in India, who work in the area of voice revealed that most SLPs had postgraduate (67.27%; n = 37) and doctorate degree (23.63%; n = 13) and worked in medical-related settings (81.81%; n = 45). Therapeutic approaches were practiced as stated in literature by 43.64% (n = 24) of SLPs. Although 56.36% (n = 31) of SLPs modified therapeutic approaches based on the client's needs (75%), literacy (16.66%) and cultural variations (8.33%). Attending Continuing Education Programs and training workshops were required to practice voice. Voice therapy methods (protocols) used by the SLPs were not uniform across India. The development of an indigenous protocol/method for voice therapy is the need of the hour.