Pitch Space Research Articles

Role of transverse dimples in thermal-hydraulic performance of dimpled enhanced tubes

This study numerically investigates the effects of transverse dimples in thermal and hydraulic performance improvement of Teardrop, Ellipsoidal-0o and Ellipsoidal-45o dimpled tubes under constant surface heat flux (q′′ = 10kW/m2) for turbulent Reynolds numbers (5000 ≤ Re ≤ 40,000). The number of dimples in the transverse direction (Star) are varied from 4 to 8 while maintaining the tube length to pitch (spacing between successive dimples) of 10 for each tube configuration. It is observed from Performance Evaluation Criteria (PEC) that Ellipsoidal-45o-Star 6 dimpled tube (Tube 7), as compared to the smooth tube, enhances the performance by 88.2% at Re = 5000 however, it reduces to 23.9% at Re = 20,000 and becomes negligible at Re = 40,000. The Ellipsoidal-45o dimples generate a non-symmetric wake and create a flow path between downstream dimples. As Star increases the flow momentum increases and a swirl flow pattern is generated and consequently enhances fluid-dimple interaction at low turbulent Re. On the contrary, Teardrop-Star 6 (Tube 2) and Ellipsoidal-0o-Star 6 (Tube 5) perform better at 20000 ≤ Re ≤ 40,000. Tube 5 produces distinct flow streams and enhances the fluid-surfaces interactions at higher Re. Therefore, it is recommended for high turbulent Re.

Vocal pitch perception with cochlear implants

Cochlear implant (CI) users often struggle to accurately perceive vocal pitch. This suggests that they are either not able to adequately use vocal pitch cues, such as temporal modulations resulting from F0, or they are using cues that do not correspond to vocal pitch. A potentially unreliable cue they may be using is formant spacing, which is correlated with vocal tract length. There is a gross, probabilistic relationship between vocal pitch and formant spacing since males tend to have both lower F0s and longer vocal tracts, but the relationship is weak, especially within gender. To examine if CI users are using the acoustic cues resulting from vocal tract length to make pitch judgments, CI users were presented with stimuli where the F0 was held constant but the formant spacing was systematically manipulated. Participants were presented with pairs of stimuli and asked to indicate the similarity of the pitch of the two stimuli using a seven-point Likert scale. The preliminary results indicate that CI users systematically perceived the changes in formant spacing as a change in pitch.

Numerical study on the cooling characteristics of cat-ear-shaped film-cooling holes on turbine blades

The turbine blade cooling technology is developing rapidly, with film cooling being the focus of research. To address the problems of poor cooling performance and low cooling efficiency of existing film holes, this paper proposes a hole structure of cat-ear-shaped films on the basis of hyperbola. The structural parameters of the proposed structure, such as inclination angle, expansion angle, length-to-diameter ratio, aperture, and cooling air inlet speed, were simulated and optimised using the finite-volume method and standard k-ε model. Furthermore, to meet the requirements of practical applications, the distribution of the film holes on a planar model was optimised numerically. The results revealed that at a hole pitch and row spacing of 5 and 20 mm, respectively, the cooling air flow exhibited patch-shaped coverage and reasonable distribution. This configuration improved the uniformity of air flow coverage and achieved a cooling efficiency of 80.12%, which was 13.12% higher than the average cooling efficiency of previously reported film holes. The cat-ear-shaped film hole demonstrated a remarkable cooling effect, which can provide a reference for optimising and selecting film hole structures on high-temperature turbine blades.

Three Audiovisual Correspondences in the Main Title for Vertigo

Saul Bass and Bernard Herrmann provided the visuals and music, respectively, for the main title of Alfred Hitchcock’s 1958 movie Vertigo. These artworks correspond with one another in three ways. First, when aligning two dimensions of visual and pitch brightness, a portion of each artwork moves through this two-dimensional space using a similar path. Second, when arranging some of the tonal materials onto a certain space, these materials transform into each other using transformations similar to those that animate some of the visual designs. Third, under partial enharmonic equivalence, these pitch spaces curl into a partly-closed and partly-open shape that closely resembles manipulated visual forms whose looped closure is partially obscured. The first and third ways shed significant light on the film’s narrative, and the first way in particular parallels the film’s central dramatic form.

In-depth feasibility study of extreme ultraviolet damascene extension: Patterning, dielectric etch, and metallization

While semiconductor logic device nodes keep moving to N3 and beyond, the backend of line (BEOL) metal pitch is aggressively scaling to improve device performance and density. BEOL damascene extension refers to interconnect with a full metal pitch of 26–21 nm. The challenges of damascene extensions are profoundly critical due to an extreme ultraviolet (EUV) single exposure limit, dielectric etch, and metallization challenges. Multipatterning is required as well as more advanced low K dielectric etch. Severe line wiggling, bad via/contact hole open, and via/trench short issue can easily be observed. Cu resistance also contributes to most of the device’s R/C delay. Before transitioning to subtractive metal integrations, there is no doubt that multipatterning damascene extension plays an important role in bridging the gap between them. In this work, we provide an in-depth feasibility study on damascene extension focusing on EUV self-aligned double patterning with cut and block assembly for 24 nm pitch line and space. EUV double patterned self-aligned via is also validated for the dual damascene test. Both continuous wave and quasiatomic layer etch are developed to achieve a wiggling-free, bridge-free, and high metal hard mask selectivity process in TEL’s new generation capacitively coupled plasma etchers. Copper metallization is demonstrated in both via and trench of a 24 nm pitch. This report provides an important insight into damascene extension feasibility for high volume manufacturing.

Flow-Induced Vibrations of a Rotated Square Tube Array Subjected to Single-Phase Cross-Flow

Abstract This paper investigates the flow-induced vibration (FIV) and possibility of fluidelastic instability occurrence in a rotated square geometry tube array through a series of experimental tests. All experiments presented here were conducted in water cross-flow. The array's pitch spacing ratio of approximately P/D = 1.64 is somewhat larger than that commonly found in typical steam generators. The stability of a single flexible tube as well as multiple flexible tubes was investigated. The tubes were free to vibrate purely in the streamwise direction or the transverse direction relative to the upstream flow. A single flexible tube, in the otherwise rigid tube array, was found to undergo large amplitude vibrations (up to 40% D) in the transverse direction. Tube vibration frequency analysis indicated the presence of two frequency components related to vorticity shedding in the array. This potential vorticity-induced vibration (VIV) and potential coupling between VIV and fluidelastic instability (FEI) are discussed in the paper. Test results for streamwise flow-induced vibrations are also presented. Results in water flow show a possible effect related to flow periodicity at low velocity. At significantly high flow velocities, the tubes are found to fully restabilize. This restabilization after VIV locking has not been previously reported as an unlocking result. The present results suggest that the flow-induced vibration of tubes in a rotated square array configuration is significantly more complex than in other geometries, particularly for the streamwise vibration case.

Feindliche Übernahme. Gottfried Weber, Adolf Bernhard Marx und die bürgerliche Harmonielehre des 19. Jahrhunderts

Current discourse on a “historically informed music theory” focusses on the 15th to 18th century, while the 19th and 20th centuries are rarely considered in this context. Rather, nineteenth- and twentieth-century music theory is frequently considered representative of “systematic” musictheoretical concepts. Nineteenth-century music theory effectively seems to be separated from eighteenth-century music theory by a categorical rupture that can be traced to the origins of the German tradition of “Harmonielehre”. These origins were closely connected to the breakdown of a music education system supported by aristocracy and church institutions during the ancien régime. In the young bourgeois society, the teaching of composition changed its social context: many representative German theorists of harmony, such as Gottfried Weber and Adolf Bernhard Marx, were autodidacts, musical amateurs with only a rudimentary knowledge of composition and music theory. Weber transferred a notion of “scientific scholarship” based on logical deduction and analogy (“Folgegleichheit”) that he had encountered during his study of law to music theory – a notion that he considered absent in the “vexatious figured bass manuals”. In a mechanistic and systematic manner the principles of scale degrees and inversions are expanded into vast combinatorial matrices of possible chord progressions. This highly speculative method separates music theory significantly from compositional practice, thus supporting the idea of impenetrable artistic decisions attributed to musical genius and independent of musical craftsmanship. Weber’s “mathematical” exploration of pitch space is representative of the “combinatorial space” (Catherine Nolan) characteristic of nineteenth-century music theory that finds its logical consequence in Arnold Schönberg’s “method of composing with twelve tones which are related only to one another”.

CFD analysis of heat transfer characteristics of rectangular solar air heater with kite shaped roughness

The present article describes the structure of the Kite shaped roughness applied to solar air heater which was designed with the help of CFD. The presented model is designed in CFD ANSYS software because it is very easy to flow fluid without any problem of intake air or fluid. The Kite shaped roughness is used to acquire all the details of the fluid in the form of the heat transfer rate and these results are carried out with RNG k-ɛ model for range of Reynolds number from 1500 to 4000. The rate of thermal characteristics enhanced with increasing pitch space between the different height of Kite shaped roughness (ek = 1.2, 2.2, 3.2 and 4.2 mm) ratio p/ek = 25 – 112.5 and observed maximum THP for Reynolds number Re = 4000, pitch space p = 125 mm, and height of Kite shaped roughness ek = 2.2 mm.

Heat Transfer Coefficient Distribution of W and Broken W Turbulators at High Reynolds Numbers

Abstract An experimental and numerical study of the convective heat transfer enhancement provided by two rib families (W and Broken W) is presented, covering Reynolds numbers (Re) between 300,000 and 900,000 in a straight channel with a rectangular cross section (AR = 1.29). These high Reynolds numbers were selected for the current study since most data in the available literature typically pertain to investigations at lower Reynolds numbers. The objective of this study is to assess the local heat transfer coefficient (HTC) enhancement (compared with a smooth channel) and the overall thermal performance, taking into account the effect of increased roughness on the friction factor, of a group of W-shaped turbulators over a wide range of Reynolds numbers. Furthermore, the effects of increasing the rib spacing on the thermal performance of the Broken W configuration are presented and discussed. The numerical results are compared against heat transfer measurements obtained using the transient liquid crystal (TLC) method. The research shows that for the Broken W turbulators, increasing the Reynolds number is associated with an overall decrease of the thermal performance while the thermal performance of the W configuration is relatively insensitive to Reynolds number. Nevertheless, the Broken W configuration delivers higher thermal performance and heat transfer compared with the W configuration for the range of Re investigated. The Broken W configuration with a pitch spacing of 10 times the rib height was shown to provide the optimal thermal performance in the configurations investigated here.

Experimental study and thermal performance evaluation of staggered cross flow heat exchangers of semi-circular tubes: I- Effect of pitch ratio and space between bases

Experimental study and thermal performance evaluation of staggered cross flow heat exchangers of semi-circular tubes: I- Effect of pitch ratio and space between bases

Thermo-Fluidic Modelling of a Heat Exchanger Tube with Conical Shaped Insert having Protrusion and Dimple Roughness

In the present work, thermo-fluidic behavior of a heat exchanger tube with conical shaped insert has been investigated with the help of finite volume method. To enhance the heat transfer rate, two different types of roughness has been used in conical insert i.e. protrusion and dimple roughness. A three-dimensional computational model with RNG turbulence model is used for the simulation and it has been performed for three different diameters (3 mm, 6 mm and 9 mm) and two different pitch space (120 mm and 180 mm) for both protrusion and dimple roughness. The present model has been validated with Dittus-Boelter equation and with Blasius equation for Nusselt number and friction factor, respectively. For a constant heat flux of 1200 W/m2, effect of roughness, diameter and pitch on Nusselt number and friction factor has been predicted for Reynold number range of 5000 to 30000. From the result, it is found that, the protrusion shaped roughness has better thermal performance factor than dimple shape and diameter of 6 mm has performed better than 3 mm and 9 mm for both the cases of roughness due to favorable flow dynamics.

Effects of Visual and Auditory Feedback in Violin and Singing Voice Pitch Matching Tasks.

Auditory-guided vocal learning is a mechanism that operates both in humans and other animal species making us capable to imitate arbitrary sounds. Both auditory memories and auditory feedback interact to guide vocal learning. This may explain why it is easier for humans to imitate the pitch of a human voice than the pitch of a synthesized sound. In this study, we compared the effects of two different feedback modalities in learning pitch-matching abilities using a synthesized pure tone in 47 participants with no prior music experience. Participants were divided into three groups: a feedback group (N = 15) receiving real-time visual feedback of their pitch as well as knowledge of results; an equal-timbre group (N = 17) receiving additional auditory feedback of the target note with a similar timbre to the instrument being used (i.e., violin or human voice); and a control group (N = 15) practicing without any feedback or knowledge of results. An additional fourth group of violin experts performed the same task for comparative purposes (N = 15). All groups were posteriorly evaluated in a transfer phase. Both experimental groups (i.e., the feedback and equal-timbre groups) improved their intonation abilities with the synthesized sound after receiving feedback. Participants from the equal-timber group seemed as capable as the feedback group of producing the required pitch with the voice after listening to the human voice, but not with the violin (although they also showed improvement). In addition, only participants receiving real-time visual feedback learned and retained in the transfer phase the mapping between the synthesized pitch and its correspondence with the produced vocal or violin pitch. It is suggested that both the effect of an objective external reward, together with the experience of exploring the pitch space with their instrument in an explicit manner, helped participants to understand how to control their pitch production, strengthening their schemas, and favoring retention.

Pool boiling heat transfer enhancement by bi-conductive surfaces

The use of the bi-conductive surface provides a promising prospect for the enhancement of the boiling phase change heat transfer. In this study, a theoretical model of two-phase flow and boiling heat transfer on bi-conductive surfaces is developed. With the consideration of thermal conductivity contrast and conjugate heat transfer, the boiling behavior is numerically investigated based on a modified lattice Boltzmann method. The bubble dynamics during the boiling process on the bi-conductive surface are reproduced and the effect of the structural size of these insets on the boiling performance is explored. The results indicate that boiling performance is enhanced on the bi-conductive surface when compared to homogeneous ones. In-plane temperature variation on the surface contributes to the pinning effect on bubble contact lines, and thus promotes boiling heat transfer. Boiling enhancement gets optimized once the embedding pitch space equal to the capillary length of the boiling fluid. Increasing the width of the insets also improves the boiling heat transfer coefficient on the bi-conductive surface under low superheat conditions, but also leads to the advance of CHF. However, changing the depth of the insets shows almost no effect on the boiling heat transfer performance.

Electron Diffusion and Advection During Nonlinear Interactions With Whistler‐Mode Waves

AbstractRadiation belt codes evolve electron dynamics due to resonant wave‐particle interactions. It is not known how to best incorporate electron dynamics in the case of a wave power spectrum that varies considerably on a “sub‐grid” timescale shorter than the computational time‐step of the radiation belt model ΔtRBM, particularly if the wave amplitude reaches high values. Timescales associated with the growth rate of thermal instabilities are very short, and are typically much shorter than ΔtRBM. We use a kinetic code to study electron interactions with whistler‐mode waves in the presence of a thermally anisotropic background. For “low” values of anisotropy, instabilities are not triggered and we observe similar results to those obtained in Allanson et al. (2020, https://doi.org/10.1029/2020JA027949), for which the diffusion roughly matched the quasilinear theory over short timescales. For “high” levels of anisotropy, wave growth via instability is triggered. Dynamics are not well described by the quasilinear theory when calculated using the average wave power. Strong electron diffusion and advection occur during the growth phase (≈100 ms). These dynamics “saturate” as the wave power saturates at ≈ 1 nT, and the advective motions dominate over the diffusive processes. The growth phase facilitates significant advection in pitch angle space via successive resonant interactions with waves of different frequencies. We suggest that this rapid advective transport during the wave growth phase may have a role to play in the electron microburst mechanism. This motivates future work on macroscopic effects of short‐timescale nonlinear processes in radiation belt modeling.

The Pythagorean comma and preference for a stretched octave

Pythagorean tuning, which derives all musical intervals of a Western chromatic scale from repeated application of a fifth and subsequent reduction (collapse) into a single octave, results in an octave interval slightly larger than 2:1, and the difference between a Pythagorean octave and a 2:1 octave is referred to as the Pythagorean comma. Empirical studies suggest that listeners prefer a stretched octave, that is, an octave interval slightly larger than 2:1. The magnitudes of the Pythagorean comma and of the stretch from a 2:1 ratio in preferred octave tuning are similar, and it is suggested these phenomena might be connected. Implications of such a similarity that are addressed include (a) how the Pythagorean comma predicts preference for a stretched octave, (b) rejection of uncertainties in tuning as a cause of preference for a stretched octave, (c) how the Pythagorean comma and preference for a stretched octave might be related to tension and musical aesthetics, (d) the nature of “scales” and “intervals” in musical and psychophysical senses, (e) the role of motion through auditory pitch space in the Pythagorean comma and preference for a stretched octave, and (f) incorporation of elements of Pythagorean tuning into the representation of the octave.

Child-directed Speech in a Norwegian Kindergarten Setting

ABSTRACT This paper presents a natural experiment using a play situation with specific toys to examine and compare the characteristics of 33 Norwegian-speaking female pedagogical employees’ child-directed speech (CDS) and adult-directed speech (ADS). Vowel pitch, duration, format frequency, and vowel space area of the vowels /a:/, /i:/, and /u:/ as well as their short counterparts /a/, /i/, and /u/ were analyzed. One-way repeated-measures ANOVAs show that the pedagogical employees spoke with a higher vowel pitch, had greater variation in their vowel pitch, and had smaller vowel space areas in CDS compared with ADS. In addition, the vowels in CDS were hypoarticulated compared with ADS. Therefore, the pedagogical employees enhanced CDS characteristics associated with attaining children’s attention and promoting social interaction between child and caregiver.

Neutronic analysis of fuel pin design for the long-life core in a pressurized water reactor

This work presents the neutronic analysis of fuel design for a long-life core in a pressurized water reactor (PWR). In order to achieve a high burnup, a high enrichment U-235 is traditionally considered without special constraints against proliferation. To counter the excess reactivity, Erbium was selected as a burnable poison due to its good depletion performance. Calculations based on a standard fuel model were carried out for the PWR type core using SRAC code system. A parametric study was performed to quantify the neutronically achievable burnup at a number of enrichment levels and for a numerous geometries covering a wide design space of lattice pitch. The fuel temperature and coolant temperature reactivity coefficients as well as the small and large void reactivity coefficients are also investigated. It was found that it is possible to achieve sufficient criticality up to 100 GWd/tHM burnup without compromising the safety parameters.

Nb-based superconducting silicon interconnect fabric for cryogenic electronics

Quantum computing for real world applications requires large arrays of qubits. This requires advanced integration technologies. In this work, we propose a simple integration method with fine interconnect pitch (10 μm) and close spacing that can overcome the large input and output (I/O) and high wiring level requirements of very large scale of quantum circuits. A system-on-wafer (SoW) packaging concept called superconducting silicon interconnect fabric (superconducting-IF), based on silicon interconnect fabric (Si-IF), is proposed, with the help of a Au interlayer technology onto the superconducting-IF. The fine-pitch and die-to-wafer-scale Au interlayer is the first demonstration of direct metal–metal thermocompression bonding (TCB) that is optimized for superconducting applications without the use of solders. The developed Au interlayer integration technology is demonstrated to be Josephson-junction-compatible (<150 °C), mechanically robust (>30 MPa), and electrically reliable down to 2 K. The mechanical strength of the Au interlayer integration method is optimized through shear tests with a shear force around 150 N on 2 × 2 mm2 dies. The transition temperature (Tc) of Nb, which is at 9 K, is experimentally verified to be unchanged after each fabrication process. Electrical and temperature cycling measurements on over 20 bonded dies of large-pitch Kelvin structures as well as fine-pitch daisy chain structures reveal reliable connections in the low-temperature regime. This work pushes quantum computing a step closer to realize its potential through 3D integration of a very large scale of quantum circuits with a high density of I/O (>10 000 per mm2) as well as high wiring capability and without introducing lossy amorphous dielectrics.

Numerical simulation on heating performances of a radiant-convective heating terminal

The hybrid radiant and convective heating system becomes more and more important in HVAC system due to its lower energy consumption and better thermal comfort. However, the existing radiant and convective heating system is complicated to provide a joint control. To solve this problem, a new kind of heating terminal of mixing radiation and convection was proposed, and its heating performances were numerically studied. Firstly, the numerical model was built, in which the air turbulent flow was calculated by the standard k-ε model, while DO radiation model was employed to solve the radiant heat transfer. Secondly, the numerical model was validated by the experimental data. Lastly, influences of the important parameters including fin heights, fin pitches and refrigerant pipe spacing on heating performances were analyzed. The results showed that the increased fin height increased the total heating flux by 7.2–25.7% and metal weight by 1.4–5.7%. It was also concluded that with the increase of fin pitch and pipe spacing, the total heat flux decreased by 1.9–11.2% and 4.3–20.1% separately, and the metal weight decreased by 2.3–6.0% and 26.1–60.2%, respectively. This study provides support for the development of the hybrid radiant-convective heating system and energy saving of buildings.

Numerical analysis of thermal-hydraulic performance of fully developed turbulent flow in heat exchanger tube with Half Moon inserts

This paper presents the numerical analysis of heat transfer characteristics of working fluid in a circular tube with inserted Half-Moon shape roughness. The Half-Moon (HM) shape roughness is specially used to upgrade the heat transfer rate in circular tubes along the length. In the present paper, we have a circular tube of length L = 1500 mm, Inner diameter Din = 30 mm and Outer diameter Do = 35 mm. The Half-Moon roughness varied with an interpolated number of holes in the range from 2 to 3 and pitch space between the HM roughness. In a circular tube, the working fluid is arranged for the Reynolds number in the category of 4000 to 32,000 and solved by the Renormalization model in Ansys fluent 14.0. In this study, we found that the heat transfer rate enhanced by a sufficient amount complained about the thermal performance of the circular tube.