Tension Profiles Research Articles

Solution properties and micellization behavior of binary mixtures of sodium salts of N-tetradeconyl alanine and N-tetradeconyl phenylalanine surfactants

Two amino acid based surfactants, N-tetradecanoyl alanine and N-tetradecanoyl phenylalanine, are studied vis-à-vis their solution behavior and micellar selfassembly. The observations are correlated to their structural features and the pH of the system. Pseudobinary mixed surfactant system model is used to understand the complex surface tension profile of the surfactants. In mixed systems, surface properties and the micellization parameters and the micellar growth has been found to depend upon the composition of the surfactant mixture which has been explained on the basis of the occurrence of non-covalent π-π and NH-π interactions between the component surfactant molecules.

Taper Tension Profile in Roll-to-Roll Rewinder: Improving Adhesive Force of Pressure-Sensitive Adhesive Film

The roll-to-roll adhesive film manufacturing process has been widely used in the field of composite film manufacture. Thus far, many research groups have reported on the variation in characteristics of pressure sensitive adhesive film according to application environment characteristics, such as temperature and external forces, failure mechanism, and structures that improve the adhesive force of the film. However, there are few studies that analyze the effects of the manufacturing process conditions on the quality of the adhesive film. In this study, we find that hoop stresses due to winding tension may cause a decrease in the quality of the adhesive layer by generating wear on its surface. Moreover, radial and hoop stresses in the wound film affect the degree of wear. This suggests that the operating conditions of the film manufacturing machine affect the quality of the pressure sensitive adhesive (PSA) film, as do the properties of the film and the environment. To improve the adhesive force of PSA film, we applied two taper tension profiles that determine the distribution of the tension applied to the winding PSA film with respect to the wound ratio, followed by experimental verification of the effects of winding.

Interfacial properties of hydrocarbon/water systems predicted by molecular dynamic simulations.

The presence of small hydrocarbons is known to reduce the interfacial tension of the gas-water interface, and this phenomenon can affect the formation of the clathrate hydrates of these gases. In this work, the interfacial behavior of the pure methane-, ethane-, and propane-water, and the ternary 90:7:3 mol. % gas mixture of (methane + ethane + propane)-water were studied with molecular dynamics simulations. The interfacial tension, γ, and z-density profiles for the gases and water from simulations of the gas-water systems were determined at the temperatures of 275.15 and 298.15 K, and pressures up to 10 MPa for methane and up to near the experimental saturation pressures of ethane and propane. The goal is to accurately calculate the interfacial tension for the hydrocarbon/water systems and to analyze the molecular behaviors at the interfaces which lead to the observed trends. At the same hydrostatic gas phase pressure, propane, ethane, and methane reduce the gas-water interfacial tension in that order. The local density of the gas molecules at the interface is enhanced relative to the bulk gas, and it was determined that about 13%-20%, 33%-40%, and 54%-59% of the gas molecules in the simulation congregated at the interfaces for the CH4-, C2H6-, and C3H8-water systems, respectively, at the different simulated hydrostatic pressure ranges. For all gases in the pressure range studied, a complete monolayer of gas had not formed at the water interface. Furthermore, a dynamic equilibrium with fast exchange between molecules at the interface and in the gas phase was observed. For the gas mixture, deviations were observed between total calculated interfacial tension, γmix, and the "ideal mixture" value, ∑xiγi,pure, calculated from the interfacial tensions of the pure gases, where xi is the mole fraction of each substance in the simulation. Some possible implications of the results on the mechanism of clathrate hydrate formation are discussed.

Introduction of a nonionic sugar-based surfactant to an oppositely charged hydrophobically modified polyelectrolyte and surfactant binary system

Interactions between polymer and surfactant provide the system a variety of properties that can be readily used by industries to achieve desired features for their products and formulations. Inclusion of a third component to the binary system is expected to present synergistic or antagonistic effects, and also lead to preferred advantages, such as reduced quantities of the components to present a comparable performance and improved environmental-benignity. In this study a sugar-based surfactant n-Dodecyl β-D-Maltoside (DM) is introduced into an oppositely charged hydrophobically modified polyelectrolyte-surfactant system comprised by a guar grafted with hydroxypropyl trimethyl ammonium chloride (Guar-HTAC) and Sodium Dodecylsulfate (SDS). By following the pattern curves of surface tension, polarity and turbidity profiles, it was found that DM plays a crucial role in the interaction process: DM leads to the formation of a soluble but surface active complex which has not been observed in the Guar-HTAC/SDS and SDS/DM systems; since DM cooperates with SDS to form micelles at much lower SDS concentrations, under certain conditions it is SDS/DM micelles instead of single SDS or DM molecules that interact with Guar-HTAC. Such behaviors are believed to be resulted from the structures of the complexes formed by the three components. Molecular structures of these formed complexes need to be investigated following this study.

Usability Assessment of a Cable-Driven Exoskeletal Robot for Hand Rehabilitation

Study design: Case series.Background: Robot-assisted rehabilitation mediated by exoskeletal devices is a popular topic of research. The biggest difficulty in the development of rehabilitation robots is the consideration of the clinical needs. This study investigated the usability of a novel cable-driven exoskeletal robot specifically designed for hand rehabilitation.Methods: The study consists of three steps, including prototype development, spasticity observation, and usability evaluation. First, we developed the prototype robot DexoHand to manipulate the patient's fingers based on the clinical needs and the cable-driven concept established in our previous work. Second, we applied DexoHand to patients with different levels of spasticity. Finally, we obtained the system usability scale (SUS) and assessed its usability.Results: Two healthy subjects were recruited in the pre-test, and 18 patients with stroke and four healthy subjects were recruited in the formal test for usability. The total SUS score obtained from the patients and healthy subjects was 94.77 ± 2.98 (n = 22), indicating an excellent level of usability. The satisfaction score was 4.74 ± 0.29 (n = 22), revealing high satisfaction with DexoHand. The tension profile measured by the cables showed the instantaneous force used to manipulate fingers among different muscle tone groups.Conclusions: DexoHand meets the clinical needs with excellent usability, satisfaction, and reliable tension force monitoring, yielding a feasible platform for robot-assisted hand rehabilitation.

Emotional Intelligence and Emotional State Effects on Simulated Flight Performance

BACKGROUND: Flight cadets' emotion is a factor of great importance to flight training. So it is of profound significance to address how emotional factors affect flight training performance. The present study aimed to investigate the relationship between emotional intelligence (EI) and simulated flight performance (SFP), and explore the mechanism of emotional state as a mediator in the effect of EI on SFP.METHODS: Ninety undergraduates took part in the study. EI (Wong and Law Emotional Intelligence Scale), neuroticism (Eysenck Personality Questionnaire Revised), anxiety (State Anxiety Inventory), and tension (Profile of Mood States) were collected. Conducted were 9 h of simulated flight training in a simulator of the Type 6 Primary Trainer. The Delphi Experts Grading Method was used to assess students' SFP. Mediation effect of emotional state was explored using regression analysis.RESULTS: EI was significantly correlated with neuroticism (r = -0.31), tension (r = -0.31), and anxiety (r = -0.31), respectively. Multiple mediation effects showed that emotional state mediated the association between EI and SFP. Tension especially mediated the associations between the Self Emotion Appraisals and Regulation of Emotion dimensions of EI and SFP. However, the Use of Emotion dimension of EI had a direct negative effect on SFP without the mediating role of emotional state.DISCUSSION: The findings indicated that EI was significantly correlated with emotional state (neuroticism, tension, and anxiety). EI may directly or indirectly affect SFP and tension played an important mediating role. Implications for the promotion of EI and emotional state to enhance performance in real flight training are discussed.Dai J, Wang H, Yang L, Wen Z. Emotional intelligence and emotional state effects on simulated flight performance. Aerosp Med Hum Perform. 2019; 90(2):101-108.

Calculation of the interfacial tension of the graphene-water interaction by molecular simulations.

We report the calculation of the solid-liquid interface tension of the graphene-water interaction by using molecular simulations. Local profiles of the interfacial tension are given through the mechanical and thermodynamic definitions. The dependence of the interfacial tension on the graphene area is investigated by applying both reaction field and Ewald summation techniques. The structure of the interfacial region close to the graphene sheet is analyzed through the profiles of the density and hydrogen bond number and the orientation of the water molecules. We complete this study by plotting the profiles of the components of the pressure tensor calculated by the Ewald summation and reaction field methods. We also investigate the case of a reaction field version consisting in applying a damped shifted force in the case of the calculation of the pressure components.

Experimental investigation on the surface tension and contact angle of Al<SUB align="right">2O<SUB align="right">3-oil and SiO<SUB align="right">2-oil nanofluids

The experimental results regarding the surface tension and contact angle of Al2O3-oil and SiO2-oil nanofluids with 0.1%~1.0% volume fraction at the temperature of 25°C~65°C are presented. The measurements illustrate that the surface tension is improved and the contact angle is reduced compared with oil based liquid. At the temperature of 25°C, for 0.5% volume fraction with 60 nm nanoparticles size, the enhancement of the surface tension is about 4.11% for Al2O3-oil nanofluids and 6.79% for SiO2-oil nanofluids. Corresponding, the weakening of the contact angle is 37.93% and 27.59%. In addition, the experimental profiles of the surface tension of Al2O3-oil and SiO2-oil nanofluids indicate that they fall with temperature, and inversely rise with the increasing of volume fraction and nanoparticles size. And the contact angle of the two kinds of nanofluids increase with nanoparticles size, whereas decrease with the increase in volume fraction. All demonstrate that the wetting properties are modified when Al2O3 and SiO2 nanoparticles are added into oil based liquid. Furthermore, the experimental phenomena are thoroughly analysed.

MorpheuS: Generating Structured Music with Constrained Patterns and Tension

Automatic music generation systems have gained in popularity and sophistication as advances in cloud computing have enabled large-scale complex computations such as deep models and optimization algorithms on personal devices. Yet, they still face an important challenge, that of long-term structure, which is key to conveying a sense of musical coherence. We present the MorpheuS music generation system designed to tackle this problem. MorpheuS' novel framework has the ability to generate polyphonic pieces with a given tension profile and long- and short-term repeated pattern structures. A mathematical model for tonal tension quantifies the tension profile and state-of-the-art pattern detection algorithms extract repeated patterns in a template piece. An efficient optimization metaheuristic, variable neighborhood search, generates music by assigning pitches that best fit the prescribed tension profile to the template rhythm while hard constraining long-term structure through the detected patterns. This ability to generate affective music with specific tension profile and long-term structure is particularly useful in a game or film music context. Music generated by the MorpheuS system has been performed live in concerts.

Model-Based Winding Tension Profile to Minimize Radial Stress in a Flexible Substrate in a Roll-to-Roll Web Transporting System

In this study, we propose a model-based taper tension profile that minimizes residual and radial stresses. In contrast to the constant torque and hyperbolic taper profile, the developed model can accurately decrease the winding tension depending upon the final decrement set by a user regardless of the maximum wound radius. Moreover, the model steeply decreases the winding tension in comparison to other tension models in the early stage, consequently, decreasing the residual stress and maximum radial stress. A hybrid model that combines the developed and conventional taper tension models is developed to expand the range of application of the model. A winding tension maker that applies the model to the winding tension controller is also developed. A variable transformation model that transforms the input of the developed model (radius ratio) to the winding time, which can be easily obtained without any sensors, is obtained. The developed model and winding tension maker are applied to an industrial roll-to-roll thin film winding machine. It is observed that local deformation in a wound thin film generated by the excessive radial stress is improved. A control technique is selected considering film characteristics, and a winding tension controller is designed using the developed tension models and winding tension maker. The designed winding tension controller decreases the maximum radial stress by 38% when compared to the case before application. Moreover, the winding length with few local deformations increases from 100 to 500 m; this confirms the superiority of the developed model and controller.

Resistant Hypertension: A Clinical Case

Introduction: Secondary hypertension corresponds to 15 % of the causes of arterial hypertension, and among them, primary hyperaldosteronism presents a variable incidence of about 3% in hypertensive patients. It has a slightly higher prevalence in women, between 30 and 60 years, and is usually unilateral. Case presentation: The authors describe the clinical case of a patient, followed by severe hypertension medicated with four antihypertensive drugs for tension stabilization, maintaining systolic arterial tensions superior to 170 mmHg. In the aetiological study of hypertension, analytical alterations suggested hyperaldosteronism and a nodular lesion was detected in the left adrenal gland. The patient was submitted to surgery and excision of the lesion was done with histological confirmation of the diagnosis of corticomedullary adenoma of the adrenal gland. The patient presented improvement of the tension profile, with the need to suspend two of the four antihypertensive drugs and to reduce the dose of the remaining ones. Conclusion: A tumor of the adrenal cortex producing aldosterone is the main cause of primary hyperaldosteronism and should always be excluded when the presence of di cult to control, severe hypertension is detected, since the standard treatment is surgical, leading to a stabilization of the tension pattern after a few months.

Vapor−Liquid Interface of the Lennard-Jones Truncated and Shifted Fluid: Comparison of Molecular Simulation, Density Gradient Theory, and Density Functional Theory

The vapor–liquid interface of the Lennard-Jones truncated and shifted (LJTS) fluid with a cutoff radius of 2.5σ is investigated for temperatures covering the range between the triple point and the critical point. Three different approaches to model the vapor–liquid interface are used: molecular dynamics (MD) simulation, density gradient theory (DGT), and density functional theory (DFT). The surface tension, pressure, and density profiles, including the oscillatory layering structure of the fluid at the interface, are investigated. The PeTS (Perturbed Truncated and Shifted) equation of state and PeTS-interfacial functional, based on perturbation theory, are used to calculate the Helmholtz free energy in the DGT and DFT approach. They are consistent with the LJTS force field model. Overall, both DGT and DFT describe the results from computer experiments well. An oscillatory layering structure is found in MD and DFT.

A new insight into the dynamics of fibre migration in ring spinning

Fibre migration in yarns is thought to take place in the spinning triangle (ST), where high tensioned edge fibres tend to compete for a low tension state by displacing inner fibres outwards to occupy the core position – the tension mechanism. The angular alignment of fibres in the drafted roving – the geometric mechanism – is also considered to contribute to this movement. Although there is an understanding of the mechanisms of fibre migration, the outward movement of core fibres, from a low to high tension state and through a thick web of gripped fibres – moving inwards – has not been fully understood. In this study, we have attempted to reanalyse the classical migration mechanism from a new perspective and establish its relationship with a real ST using a new reflective imaging technique. The study findings suggest that pre-twist region in the ST, which is generally considered to be stable at one location, shows a rather dynamic oscillatory movement – a result of continuous change in ST tension profile. Spinning trials were conducted to confirm a relationship between pre-twist movement and degree of fibre migration.

Stresses and Defects in Roll Products: A Review of Stress Models and Control Techniques

Coiling is a method used to store long and thin products, such as a wire or film, made out of steel, plastic, or rubber, in a volumeefficient manner, and is the final phase of most roll product manufacturing systems. Internal stress in a roll product is exerted during this process, and can decrease the productivity by causing buckling or telescoping. Therefore, this issue has warranted interest in the roll-to-roll manufacturing process, and significant effort has gone into improving the internal stress while avoiding the loosening and slippage between adjacent coiled layers. In this paper, we review various studies on the dynamics of internal stresses, as well as the control techniques used to improve the stress and quality of a roll product. Initially, the various defects occurring in roll products and a radial stress generating such defects are introduced, and mathematical models applied to analyze the dynamics of stress with respect to the characteristics of the coiled materials and the coiling process conditions are compared. In addition, techniques to control the internal stress are introduced. Finally, tension profiles used in the coiled tension control technique are introduced and compared. This review will be useful for understanding the defects that occur in roll products due to internal stress, as well as alternative methods to improve the quality of a coiled roll.

Prediction of foaming and surface tension of lean MDEA solutions with corrosion inhibitor (bis(2-hydroxyethyl)cocoalkylamine) in continuous foam fractionation column

ABSTRACTAmine foaming is a common problem in gas sweetening unit. Prediction of foaming behavior will help in unraveling the operational challenges faced by the gas industry. This study was performed with the aim of predicting the foam volume and surface tension of lean methyldiethanolamine solutions in presence of bis(2-hydroxyethyl)cocoalkylamine (BHCL) corrosion inhibitor using continuous foam fractionation technique. The effect of BHCL as a model foam creators on foaming tendency was explored. The obtained experimental results were used to determine the empirical parameters k and n of the power law relation previously derived for high viscous fluid (i.e., ), both and are dimensionless parameters. The prediction model gave a good agreement with the experimentally observed results (<6% deviation). The foam height model helped in envisaging the surface tension profile and in turn the separation performance and efficiency of foam creators. The foam height increased with increasing superficial gas velocity and BHCL concentration. For low BHCL concentrations, the minimum surface tension was noticed at superficial gas velocity of 0.02 m/s.

Enhanced interfacial deformation in a Marangoni flow: A measure of the dynamical surface tension

We investigate the flows and deformations resulting from the deposition of awater solublesurfactant at a bare oil-water interface. Once the surfactant is deposited, we show thatthe oil-water interface is deformed with a water bump rising upward into the oil. For agiven oil, the maximal deformation—located at the surfactant deposition point—decreaseswith the oil-layer thickness. We also observe a critical oil-layer thickness below whichthe deformation becomes as large as the oil layer, leading to the rupture of this layer andan oil-water dewetting. Experimentally, it is found that this critical thickness depends onthe oil density and viscosity. We then provide an analytical modelization that explainsquantitatively all these experimental features. In particular, our analysis allows us to derivean analytical relationship between the vertical profile of the oil-water interface and thein-plane surface tension profile. Therefore, we propose that the monitoring of the interfacevertical shape can be used as a new spatially resolved tensiometry technique.

The Effects of Glaucoma Drainage Devices on Oxygen Tension, Glycolytic Metabolites, and Metabolomics Profile of Aqueous Humor in the Rabbit.

PurposeGlaucoma drainage device (GDD) implantation can lead to corneal decompensation. We evaluated changes over time in oxygen tension and in the metabolic environment of the aqueous humor after GDD implantation in the rabbit eye.MethodsAhmed Glaucoma Valves were implanted in the left eyes of eight male New Zealand white rabbits. Right eyes were used as a control. Oxygen tension was measured immediately before surgery and at 1 and 2 months postoperation. Aqueous humor was collected from the surgical and control eyes at 1, 2, and 5 months postoperation. Aqueous humor samples collected at 1 and 5 months postoperation were selected for broad-spectrum metabolomics analysis using ultra-performance liquid chromatography-time of flight-mass spectrometry (UPLC TOF-MS). Multivariate analysis methods were used to identify metabolite profiles that separated the surgical and control eye at 1 and 5 months.ResultsThere was a significant decrease in oxygen tension in aqueous humor of the surgical eyes (9 mm Hg, 95% confidence interval [CI]: −14.7 to −3.5). Differences in the metabolic profiles between the surgical and control eye at 1 and 5 months were observed, as were differences for the surgical eye at 1 and 5 months. In addition, a metabolite profile was identified that differentiated the surgical eyes at 1 and 5 months.ConclusionChanges in the oxygen tension and metabolic intermediates occur within the aqueous humor as early as 1 month after GDD implantation.Translational RelevanceCorneal decompensation following GDD implantation could be secondary to disruption of the normal aqueous circulation, resulting in hypoxia and an altered metabolic profile. Alterations to the GDD design might minimize aqueous disruption and prevent corneal decompensation.

Novel Gemini cationic surfactants as anti-corrosion for X-65 steel dissolution in oilfield produced water under sweet conditions: Combined experimental and computational investigations

Two new sequences of Gemini di-quaternary ammonium salts were synthesized characterized by FTIR and 1HNMR spectroscopic techniques and evaluated as corrosion inhibitor for X-65 steel dissolution in deep oil wells formation water saturated with CO2. The anti-corrosion performance of these compounds was studied by different electrochemical techniques i.e. (potentiodynamic polarization and AC impedance methods), Surface morphology (SEM and EDX) analysis and quantum chemical calculations. Results showed that the synthesized compounds were of mixed-type inhibitors and the inhibition capability was influenced by the inhibitor dose and the spacer substitution in their structure as indicated by Tafel plots. Surface active parameters were determined from the surface tension profile. The synthesized compounds adsorbed via Langmuir adsorption model with physiochemical adsorption as inferred from the standard free energy (ΔG°ads) values. Surface morphology (SEM and EDX) data for inhibitor (II) shows the development of adsorbed film on steel specimen. Finally, the experimental results were supported by the quantum chemical calculations using DFT theory.

Le rôle des personnages dans les rouages de l'intrigue

Cet article propose une synthèse d'un ouvrage qui pose les fondements d'une approche narratologique d'orientation stylistique et rhétorique visant à décrire avec le plus de précision possible le mécanisme des récits littéraires immersifs et intrigants. Partant du constat de l'existence d'une forte polysémie autour de la notion d'intrigue, je proposerai de partir d'une définition fonctionnelle apte à souligner le rapport étroit entre la dynamique du récit et la mise en intrigue, qui noue, entretien et dénoue une tension dans l'expérience esthétique. J’évoquerai également la manière dont la caractérisation des personnages et la mutabilité de leurs rôles peuvent déterminer de manière essentielle le profil de la tension narrative.*******************************************************O papel dos personagens na dinâmica do enredoEste artigo fornece um resumo de um livro que estabelece as bases para uma abordagem estilística e retórica da narratologia cujo objetivo é descrever com a maior precisão possível o mecanismo de narrativas literárias imersivas e intrigantes. Observando a existência de uma forte polissemia em torno da noção de trama, proponho começar com uma definição funcionalista capaz de enfatizar a estreita relação entre a dinâmica narrativa e o empenho, que constrói, mantém e resolve a tensão na experiência estética. Eu também menciono como a caracterização dos personagens e a mutabilidade de seus papéis podem determinar de forma essencial o perfil da tensão narrativa.Palavras-chave: Trama; Tensão narrativa; Caráter; Narratologia; Retórica; Estilística

Transverse vibration and instability of axially travelling web subjected to non-homogeneous tension

In many engineering applications of roll-to-roll manufacturing, the inhomogeneity in the tension profile applied at both the ends of web is apparent, which cannot be completely ignored in the modeling so as to accurately predict the dynamic behaviors of the travelling web. In this paper, transverse vibration and instability of axially travelling web subjected to parabolic tension profile are investigated. The governing equations of motion are derived by employing the Hamilton principle. The Galerkin method is used to compute the complex natural frequencies and mode shapes. The instability of travelling web versus different axial velocities is studied. This paper focuses on the influence of tension inhomogeneity on the critical velocity and mode shape. The sensitivity of aspect ratio and average tension to the tension inhomogeneity are also discussed. The critical velocities of the travelling web may be greatly decreased because of the tension inhomogeneity and a small tension inhomogeneity is enough to change the mode shapes completely.