Front Back Research Articles

On the physical mechanism of front–back asymmetry of non-breaking gravity–capillary waves

Abstract

Mechanical Oscillations in 2D Collective Cell Migration: The Elastic Turbulence

Various types of mechanical waves such as propagative waves and standing waves are observed during 2D collective cell migration. Propagative waves are generated during monolayer free expansion while standing waves are generated during swirling motion of a confluent monolayer. Significant attempts have been made to describe the main characteristics of mechanical waves obtained within various experimental systems. However, much less attention is paid to correlate the viscoelasticity with the generated oscillatory instabilities. Mechanical waves have been recognized during flow of various viscoelastic systems under low Reynolds number and called “the elastic turbulence”. In addition to Reynolds number, Weissenberg number is needed for characterizing the elastic turbulence. The viscoelastic resistive force generated during collective cell migration as a consequence of a residual stress accumulation is capable of inducing apparent inertial effects by balancing with other forces such as the surface tension force, the traction force, and the resultant force responsible for cell migration. The resultant force represents a product of various biochemical processes such as cell signaling and gene expression. The force balance induces (1) front flow and back flow in the direction of cell migration as characteristics of the propagative waves and (2) inflow and outflow perpendicular to the direction of migration as characteristics of the standing waves. The apparent inertial effects are essential for appearing the elastic turbulence and represent the characteristic of (1) the back flow during the monolayer free expansion and (2) the inflow during cell swirling motion within a confluent monolayer.

Front Matter and Back Matter

Front Matter and Back Matter

Wave asymmetry and particle orbits in irregular wave models

Abstract

Study of recombination process of lead-free cesium titanium (IV) based single halide and mixed halide perovskite compounds absorbing layer

The present research work represents the study of the recombination process at different positions of a hetero junction solar cell. The study for recombination process at depletion region, quasi-neutral region, front (right) contact region and back (left) contact region for lead-free Cesium Titanium (IV) based single halide perovskites compounds viz Cs2TiBr6, Cs2TiI6, Cs2TiCl6, and Cs2TiF6 and mixed halide compounds such asCs2TiI1Br5, Cs2TiI2Br4, Cs2TiI3Br3, Cs2TiI4Br2,and Cs2TiI5Br1was studied using SCAPS-1D device simulator. The cell architecture used for the study is FTO/TiO2/absorbing layer/CuSCN/Ag. Open circuit voltage (VOC) is a key performance parameter to understand the recombination process at the front contact and back contact interfaces of a solar cell device. This research article enumerated the total recombination current density (JTot. Recom), bulk recombination rate (JBulk), Schckley-Read-Hall recombination rate or defect recombination rate (JSRH) for the solar cell device.

Patterns of Misidentified Vowels in Individuals With Dysarthria Secondary to Amyotrophic Lateral Sclerosis

Purpose The current study examines the pattern of misidentified vowels produced by individuals with dysarthria secondary to amyotrophic lateral sclerosis (ALS). Method Twenty-three individuals with ALS and 22 typical individuals produced 10 monophthongs in an /h/-vowel-/d/ context. One hundred thirty-five listeners completed a forced-choice vowel identification test. Misidentified vowels were examined in terms of the target vowel categories (front-back; low-mid-high) and the direction of misidentification (the directional pattern when the target vowel was misidentified, e.g., misidentification "to a lower vowel"). In addition, acoustic predictors of vowel misidentifications were tested based on log first formant (F1), log second formant, log F1 vowel inherent spectral change, log second formant vowel inherent spectral change, and vowel duration. Results First, high and mid vowels were more frequently misidentified than low vowels for all speaker groups. Second, front and back vowels were misidentified at a similar rate for both the Mild and Severe groups, whereas back vowels were more frequently misidentified than front vowels in typical individuals. Regarding the direction of vowel misidentification, vowel errors were mostly made within the same backness (front-back) category for all groups. In addition, more errors were found toward a lower vowel category than toward a higher vowel category in the Severe group, but not in the Mild group. Overall, log F1 difference was identified as a consistent acoustic predictor of the main vowel misidentification pattern. Conclusion Frequent misidentifications in the vowel height dimension and the acoustic predictor, F1, suggest that limited tongue height control is the major articulatory dysfunction in individuals with ALS. Clinical implications regarding this finding are discussed.

Acquisition and Acoustic Patterns of Southern American English /l/ in Young Children.

Purpose The aim of the current study was to examine /l/ developmental patterns in young learners of Southern American English, especially in relation to the effect of word position and phonetic contexts. Method Eighteen children with typically developing speech, aged between 2 and 5 years, produced monosyllabic single words containing singleton /l/ in different word positions (pre- vs. postvocalic /l/) across different vowel contexts (high front vs. low back) and cluster /l/ in different consonant contexts (/pl, bl/ vs. /kl, gl/). Each production was analyzed for its accuracy and acoustic patterns as measured by the first two formant frequencies and their difference (F1, F2, and F2-F1). Results There was great individual variability in /l/ acquisition patterns, with some 2- and 3-year-olds reaching 100% accuracy for prevocalic /l/, while others were below 70%. Overall, accuracy of prevocalic /l/ was higher than that of postvocalic /l/. Acoustic patterns of pre- and postvocalic /l/ showed greater differences in younger children and less apparent differences in 5-year-olds. There were no statistically significant differences between the acoustic patterns of /l/ coded as perceptually acceptable and those coded as misarticulated. There was also no apparent effect of vowel and consonant contexts on /l/ patterns. Conclusion The accuracy patterns of this study suggest an earlier development of /l/, especially prevocalic /l/, than has been reported in previous studies. The differences in acoustic patterns between pre- and postvocalic /l/, which become less apparent with age, may suggest that children alter the way they articulate /l/ with age. No significant acoustic differences between acceptable and misarticulated /l/, especially postvocalic /l/, suggest a gradient nature of /l/ that is dialect specific. This suggests the need for careful consideration of a child's dialect/language background when studying /l/.

Deep and CNN fusion method for binaural sound source localisation

In binaural sound source localisation, front–back confusion is often the challenging problem when localising sources in the noisy or reverberant environments. Hence, a novel algorithm fusing deep and convolutional neural network (CNN) is proposed to address this issue. First, joint features, which consist of interaural level differences (ILDs) and cross-correlation function (CCF) within a lag range, are extracted from binaural signals. Second, with the extracted CCF–ILD features, CNN is used for the front–back classification task, while deep neural network is used for azimuth classification task. The front–back features extracted by the CNN can be leveraged as additional information for the sound source localisation task. Also, an angle-loss function is designed to avoid the overfitting problem and to improve the generalisation ability of this method in adverse acoustic conditions. Finally, two branches are concatenated and then followed by an output layer, which generates the posterior probability of azimuth angles, and the azimuth corresponding to the maximum posterior probability is chosen as the direction of sound source. Experimental results demonstrate the effectiveness of the authors’ method for front–back decision and azimuth estimation in noisy and reverberant environments.

전자파 차폐 소재와 전통배자를 활용한 출산 전 · 후 착용이 지속가능한 임부복 디자인 개발

Baeja, the sleeveless vest of the hanbok, is not constraining to the body. Therefore it is comfortable and convenient for pregnant women to wear. This study is to develop a Baeja inspired maternity dress during the pre and postnatal period. The value of this study is to facilitate sustainable maternity clothes and discover a new integrated maternity dress with high-tech materials. The previous literature and relics traditional Baeja of the Joseon Dynasty and the latest electromagnetic shielding materials were reviewed. The five-stage design process model was developed, and five sustainable maternity dresses were produced. Design 1 was made up of dak paper, simgam. Based on the shape of Kalgit(knife-shaped collar), a copper composite electromagnetic shielding fabric was applied to simgam of apgil to protect the abdomen from electromagnetic waves. It can be easily layered with any kind of style. Design 2 is Baeja of Bangryeonggit. It is a longer front and shorter back length to cover the pregnant stomach. An electromagnetic shielding material containing silver yarn was applied, and the pastel violet color is to express a feminine image. Design 3 is Deungguhli-shaped Baeja. It is possible to adjust the size using the long string, and this has a longer front and shorter back. It covers the chest and the abdomen up entirely and is made of electromagnetic shielding material containing stainless steel yarns for effective somatotype complementing and body protection. Design 4 is a Daegeum-shaped Baeja git. It is possible to adjust the size using the long belt, which connects the front part to the rear part. Wool was applied to the outer fabric, and a piece of functional fabric for shielding from electromagnetic waves was used as a lining for practicality when wearing over a full dress. Design 5 is a Gaegeum-shaped git for boys and Baeja, which has a longer front and shorter back. Silver micro-fiber composite cotton was used to shield from electromagnetic waves, and traditional, complementary colors of the outer fabric and the lining were applied. As stated above, in this study, functional, aesthetical, and eco-friendly sustainable maternity dress designs for women before and after childbirth were developed using periodic characteristics of Baeja of the Joseon Dynasty era. This study has significance by developing new designs that are traditional and modern at the same time for women to wear in daily life and the workplace using modern and functional materials and discovering the new potential for the development of traditional clothing.

Agreement Between the Iron Path App and a Linear Position Transducer for Measuring Average Concentric Velocity and Range of Motion of Barbell Exercises.

Kasovic, J, Martin, B, Carzoli, JP, Zourdos, MC, and Fahs, CA. Agreement between the Iron Path app and a linear position transducer for measuring average concentric velocity and range of motion of barbell exercises. J Strength Cond Res 35(2S): S95-S101, 2021-The purpose of this study was to compare average concentric velocity (ACV) and range of motion (ROM) values measured by the Iron Path (IP) app to the previously validated Open Barbell System (OBS) linear position transducer during the front and back squat and conventional and sumo deadlift. Twenty-seven men and women (21 ± 3 years old; 76.7 ± 14.5 kg; 1.72 ± 0.09 m) with squat and deadlift training experience completed a modified one repetition maximum protocol on 4 separate occasions in a randomized order. The IP app and OBS device recorded ACV and ROM during each protocol. The level of statistical significant was set at p ≤ 0.05. Bland-Altman plots showed fairly large limits of agreement for both ACV and ROM. Furthermore, 95% confidence intervals for the intraclass correlation coefficients indicated the agreement in ACV between the devices for each of the 4 lifts to range from 0.648-0.876 to 0.849-0.930 and for agreement in ROM between devices to range from -0.053-0.480 to 0.545-0.770. Compared with the OBS, the IP app recorded significantly (p < 0.05) lower ACV values for the front squat and back squat and greater ROM values for the sumo deadlift. We suggest the IP app should not be used in place of a validated linear position transducer for measuring ACV or ROM for barbell lifts.

Front Matter and Back Matter

Front Matter and Back Matter

Experimental and numerical investigations on effect of blade trimming on aerodynamic performance of squirrel cage fan

The impeller of squirrel cage fan exerts great effects on the internal flow fields and fan aerodynamic performance. On the premise of maintained impeller-volute tongue distance and production cost reduction, this paper proposes a blade trimming method focusing on axial modification of blade inlet in an attempt to improve the impeller flow condition and further the aerodynamic performance of squirrel cage fan, which is divided into blade full trimming and part trimming. Aerodynamic performance tests and numerical simulations are performed to explore the effect of blade trimming on the fan aerodynamic performance and the related flow mechanisms. The results show that the blade trimming with proper trimming parameter enables the fan to achieve higher fan aerodynamic performance in terms of total pressure efficiency and static pressure rise, between which full trimming is preferable to part trimming. With the optimum full trimming of blade, the axial distributions of mass flow at the impeller inlet and outlet become more uniform. The dimension of inactive zone near the front span is decreased. On the blade pressure surface, the forces are reduced with obvious improvement of gradients near the front span and back span. A better match between impeller and volute tongue is achieved as the decreases of reversed flow coefficients at the impeller inlet and outlet and recirculated flow coefficient in the volute.

Progressions of core stabilization exercises based on postural control challenge assessment.

The intensity progression of core stabilization exercises (CSEs) is usually based on personal criteria rather than on objective parameters. To develop exercise progressions for four of the most common CSEs based on the postural control challenge imposed on the participants, and to analyze the effect of participants' sex and postural control level on these progressions. Seventy-six males and females performed five variations of front bridge, back bridge, side bridge and bird-dog exercises on two force platforms. The mean velocity of the center of pressure displacement was calculated to assess exercise intensity through the measurement of the participants' body sway (PBS). In general, long bridges produced higher PBS than short bridges, bridging with single leg support produced higher PBS than bridging with double leg support and bridging on a hemisphere ball produced higher PBS than bridging on the floor. The most difficult bridging variations were those performed on a hemisphere ball with single leg support. Regarding the bird-dog, two-point positions produced higher PBS than three-point positions and the positions performed on a hemisphere ball produced higher PBS than those performed on the floor. The CSE progressions obtained by males and females were very similar. However, the participants with high trunk control showed less significant differences between exercise variations than the participants with low trunk control, which shows the need to individualize the progressions according to the participants' training level. Overall, this study provides useful information to guide the prescription of CSE progressions in young physically active individuals.

Differential piezoresistive wind speed sensor on flexible substrate

In this Letter, a differential piezoresitive wind speed sensor on a flexible substrate is proposed. Two piezoresistors with the same size are fabricated on the front surface and back surface of the substrate, respectively. When the wind blows towards the device, the flexible substrate is bent, increasing the resistance on the front surface and reducing that on the back surface. The proposed sensor is fabricated on a polyethylene terephthalate substrate. Wind speed experiments are performed in the wind tunnel and the results demonstrate that the sensor can measure the wind speed up to about 20 m/s.

FEM Validation of Front End and Back End Defects Evolution in AA6063 and AA6082 Aluminum Alloys Profiles

The reduction of scraps related to back end defects (i.e. billet skin contamination) and front end defects (i.e. charge welds) is gaining nowadays an increasing industrial interest in order to obtain greater process efficiency. Today, extrusion industrial practice faces the issue by means of technician’s experience, empirical rules or, in most critical profiles, through time consuming and expensive experimental analyses. On the other side, FEM simulation of extrusion dies is becoming a common support tool for the design of new critical dies. Stating this scenario, the possibility to include the prediction of front end and back end defects evolution as simulation output can then be easily obtained at almost comparable computational costs. In this paper the FEM code Altair HyperXtrude® is used for the simulation of 2 industrial cases made by AA6063 and AA6082 alloys following the transient moving boundaries approach. Experimentally, the profiles were extruded, sectioned, polished and etched with caustic soda in order to reveal and measure front and back end development in front of and behind the profile stop mark. The data obtained from experimental analyses are initially discussed referring to billet skin contamination and charge weld evolution, then compared to industrial experience, to theoretical and empirical methods available in literature and to FEM results in order to evaluate pros and cons of each evaluation method.

A Comparison of Muscle Activation Among the Front Squat, Overhead Squat, Back Extension and Plank

A Comparison of Muscle Activation Among the Front Squat, Overhead Squat, Back Extension and Plank

The Performance of V-Trough Solar Concentrator Photovoltaic Systems at Varying Panel Surface Temperatures

The photovoltaic (PV) panel performances are dependent upon many factors. A study was executed to ascertain the effect of a V-Trough Concentrator (VTC) to be engaged on a PV Panel in this research where the performance of PV panels are compared at different surface temperatures both back and front. The experiment was conducted using two similar rated monocrystalline PV panels. One of the PV panels was installed with a VTC while the other is without the VTC that served as Control for benchmark purposes. The optimum VTC selected is a 60° VTC. Both PV systems were built with a lower supporting mechanism and were placed to operate under similar operating and weather situations, while the PV panel surface temperature both front surface and back surface, Open Circuit Voltage (Voc), as well as Short-Circuit Current (Isc) readings are being recorded down at specific time. The theoretical output is determined and compared. This paper ends with a presentation of the results obtained in a study on the PV panel surfaces temperature in relation to its performance by PV system using a 60o VTC.

Finite Element Modeling of the Membrane Module

The design and size of the membrane module package have a significant impact on its characteristics. It is necessary to use the finite element modeling calculation of the frequency response of the membrane module’s membrane due to the complexity of the package design. In this study the method of the thin dielectric membrane modeling by the structural and acoustic analysis in the ANSYS software is proposed. This method allows us to perform the calculation taking into account the influence of the front and back chamber size. The dependences of resonance frequency of the front chamber and back chamber on its geometric sizes are obtained. It is shown that by increasing the back chamber size, the value of the membrane sensitivity approaches its value in the open space. The membrane modules’ frequency response is compared and it shown that the presence of the front and back chambers significantly affects the values of the resonance frequency and sensitivity. The method of setting residual stresses in the membrane using thermal impact is used. A complicatedly deformed state of the membrane, called the buckling effect, is obtained. The dielectric membrane’s sensitivity with allowance for the buckling effect is calculated. The results are analyzed and it is shown that the calculated sensitivity of the membrane taking the buckling effect into account has a good coincidence with the measurement results. The proposed method enables us to calculate the membrane module’s frequency response taking the influence of the package design’s peculiarities into account and also the residual stresses in the membrane. The use of structural-acoustic analysis enables us to achieve more accurate results while calculating the membrane frequency response, which increases the efficiency of designing the acoustic pressure transducers, and ensures achieving the product’s optimal characteristics.

Design and analysis of novel tri‐active layer channel amorphous‐IGZO thin‐film transistor

Among high-field mobility materials, amorphous indium–gallium–zinc oxide (In–Ga–ZnO) (α-IGZO) has been prominent for their use in thin-film transistors (TFTs). In this Letter, the authors present a novel structure of TFT with tri-active layer (TAL) channel consisting of α-IGZO and In–SnO (ITO) materials. Further, the simulation-based analysis of the proposed device and characteristics in comparison to the single and double active layer channel structures have been reported. This work also analyses the effect of front–back channel thickness-ratios in double-active layer channel TFTs. The proposed TAL channel TFT describes improved switching parameters such as lower threshold voltage (V TH) − 4.24 V, high field-effect mobility (µ FE) 38.4 cm2/V-s, moderate subthreshold swing 0.398 mV/decade, and reasonably high ON-to-OFF current ratio (I ON/I OFF) 0.18 × 1012. The electrical characteristics persuade the significance of the proposed structure in next-generation flat-panel displays.

Tasting names: Systematic investigations of taste-speech sounds associations

Product names can be developed to effectively convey specific sensory attributes to the consumer. Most of the previous research on crossmodal correspondences has shown that people selectively associate words (e.g., ‘Maluma’, ‘Takete’) with taste attributes. To provide practical insights for naming new products in the food industry, it is important to obtain a more nuanced understanding concerning those properties of speech sounds (i.e., vowels, consonants) influencing people’s taste expectations. In this study, we investigated taste-speech sound correspondences by systematically manipulating the vowels and consonants comprising fictitious brand names. Based on the literature on crossmodal correspondences and sound symbolism, we investigated which vowels/consonants contribute more to the association between speech sounds and tastes (sweet/sour/salty/bitter). Across three experiments, we systematically varied vowels (front: [i][e], back: [a][u][o]), and affricate consonants (e.g., fricative: [f][s], stop: [p][t]) as well as voiced/voiceless consonants (e.g., voiced: [b][d], voiceless: [f][k]). Japanese participants were presented with brand names and had to evaluate the taste that they expected the product to have. The results revealed that: (1) front (back) vowels increased expected sweetness (bitterness), (2) fricative (stop) consonants increased expected sweetness (saltiness/bitterness), (3) voiceless (voiced) consonants increased expected sweetness/sourness (saltiness/bitterness). Moreover, consonants, which were pronounced first in the brand names, exerted a greater influence on expected taste than did the vowels. Taken together, these findings help advance theoretical foundations in sound-taste correspondences research as well as provide practical contributions to the food practitioners to develop predictive product names.