Strike Zone Research Articles

Lightning Strike Danger Zone Detector System Integrated with Smartphone

The potential for direct hits and bounces from buildings during thunderstorms can endanger pedestrians in the open area of the Faculty of Engineering Untirta campus. So far, there has been no danger warning in the open area so that pedestrians in the area are not prepared if unwanted things happen, especially when there is rain and lightning. Direct lightning strikes are one of the hydrometeorological events that need to be watched out for. Because of its impact that can cause damage to objects and casualties if exposed to humans. The campus area has a fairly large open area, making the threat of lightning strikes can occur at any time, especially during the rainy season. The purpose of this research is to design and implement a direct lightning strike hazard zone detection device in the campus area of the Faculty of Engineering UNTIRTA located in the city of Cilegon. The stages of research carried out include analyzing the open area of the FT campus using the Rolling sphere method. After that, plotting the area of the analysis results. Then an area detection tool was created which is categorized as a direct lightning strike danger zone that is integrated with Smartphone notifications.

Neotectonic structures of the Eastern Taimyr and their relationship with gravitational anomalies and seismicity

The study of the newest structures of the east of the Taimyr Peninsula, expressed in relief, was carried out using the structural and geomorphological method, which allows to identify the latest deformations, which were compared with the features of the gravitational field and its transformants. A good correspondence between gravitational anomalies and the magnitude of erosion uplifts is shown, and the confinement of the selected blocks and their boundaries to the peculiarities of the transformant field is established. The zones of seismicity within the Eastern Taimyr and adjacent territories tend to faults active in the Cenozoic period, as well as to an elongated zone of contrasting values of gravitational anomalies and their transformants of the strike zone.

Flying in the Strike Zone: Urban Air Mobility and Wildlife Strike Prevention

The number and rate of wildlife strikes continue to increase worldwide. More than 30 years of wildlife strike data indicate that approximately 92% of wildlife strikes for commercial aircraft occur at or below 3500 ft above ground level. Since urban air mobility (UAM) operations are envisioned to carry cargo and passengers up to an altitude of 4000 ft above ground level, UAM operations will face increased exposure to wildlife strike risks throughout their operations. Moreover, the comparatively small size of UAM aircraft, proposed cruising speeds of up to 170 kt, and quieter electric engines are expected to reduce opportunities for threat perception and evasive maneuvers by aircraft operators and wildlife. This paper presents how well-established wildlife strike prevention measures can be adapted to meet the needs of UAM operations and how, with new technology, original equipment manufacturers (OEMs), regulatory agencies, aircraft operators, communities, airspace managers, and vertiport operators can work together to enhance safety.

Strength, speed, and anthropometric predictors of in-game batting performance in baseball

ABSTRACT A key focus of sports science research is the identification of quantitative assessments that can predict players’ on-field performance and developmental potential. Despite efforts to establish predictive models, there are few validated measures that show reliable associations and large gaps in understanding. Here, we test a multidimensional battery of assessments developed through the USA Baseball, Prospect Development Pipeline that capture strength and functional movement abilities, and anthropometric characteristics, in a two-year cohort of collegiate baseball players from the Appalachian League. Swing propensity metrics for Zone Contact Percentage (ZCP: proportion pitches in strike zone swung at and hit) and Hard-Hit Percentage (HHP: proportion in-play balls with exit velocity ≥ 95 mph) were calculated on 189 players. Models testing hierarchical combinations of anthropometric and anthropometric plus assessment data were implemented using nested cross-validation with random forest and elastic net regression. Results indicate that anthropometric features account for 29% of variance in ZCP and 50–55% of HHP, while the addition of assessment contributed an additional 1–3% to ZCP and 5–12% to HHP, with top predictors coming from PDP strength and power assessments. These findings delineate contributions of andromorphic and physical abilities to in-game baseball performance using a validated assessment battery and advanced game statistics.

Мониторинговые электротомографические исследования зоны Иссык-Атинского разлома (Северный Тянь-Шань)

In 2023, monitoring geophysical studies were carried out using the electrical resistivity tomography (ERT) method along three profiles that cross the strike zone of the Issyk-Ata fault in the transverse direction. A detailed study was carried out of the observed variations in apparent electrical resistivity, which characterize the change in the electrical properties of the upper part of the Earth's crust section with a 40-minute discretization in time. Using the analysis of difference pseudo-sections of apparent resistivity, constructed based on the results of ERT monitoring, the most informative pseudo-depth interval from the point of view of geoelectric activity was determined for all three monitoring profiles. Accordingly, for a pseudo-depth of 24 m on each monitoring profile, an assessment was made of the geodynamic activity of these sections of the Issyk-Ata fault based on an analysis of the magnitude of two parameters: the amplitude of apparent resistivity variations and the correlation coefficient of electrical resistivity variations with lunar-solar solid tides. High values of these parameters, in our opinion, determine the location of modern active fault zones.

Evaluating plate discipline in Major League Baseball with Bayesian Additive Regression Trees

Abstract We introduce a three-step framework to determine at which pitches Major League batters should swing. Unlike traditional plate discipline metrics, which implicitly assume that all batters should always swing at (resp. take) pitches inside (resp. outside) the strike zone, our approach explicitly accounts not only for the players and umpires involved in the pitch but also in-game contextual information like the number of outs, the count, baserunners, and score. We first fit flexible Bayesian nonparametric models to estimate (i) the probability that the pitch is called a strike if the batter takes the pitch; (ii) the probability that the batter makes contact if he swings; and (iii) the number of runs the batting team is expected to score following each pitch outcome (e.g. swing and miss, take a called strike, etc.). We then combine these intermediate estimates to determine whether swinging increases the batting team’s run expectancy. Our approach enables natural uncertainty propagation so that we can not only determine the optimal swing/take decision but also quantify our confidence in that decision. We illustrate our framework using a case study of pitches faced by Mike Trout in 2019.

Comparison of Pitching Kinematics between Normal-Weight and Overweight Group in High School Baseball Pitchers

This study compared differences in pitching kinematics between normal-weight and overweight high school baseball pitchers. Twenty male pitchers were included in the study. According to the 2020 guidelines on the Body Mass Index (BMI) standard for children and adolescents by the Korean Society for the Study of Obesity, 10 participants with BMI below the 85% percentile were assigned to the normal-weight group, and 10 participants with BMI above the 85% percentile were assigned to the overweight group. The two groups threw 10 trials for a fastball with maximum effort. Out of 10 trials, three pitches thrown in the strike zone with the fastest velocity were extracted. The mean ball velocity was measured, and the mean and maximum angle and angular velocity of the knee, pelvis, trunk, shoulder, and elbow joints were calculated. The differences in the ball velocity, angle, and angular velocity between the two groups were compared using an independent t-test (p<0.05). There were no differences in mean ball velocity between the two groups. However, compared with the normal-weight group, the overweight group showed smaller knee flexion, trunk forward tilt, trunk rotation, maximum trunk angular velocity, shoulder external rotation and maximum shoulder external rotation, while shoulder abduction and maximum elbow flexion were greater. These results suggest that the overweight group may have a high risk of soft tissue damage in the knee, shoulder, and elbow joints caused by limited movement of the trunk and inefficient movement between the extremities during power pitching.

Development of steady-state fusion reactor by Helical Fusion

The Helical Fusion group (Helical Fusion Co., Ltd. in Japan and Helical Fusion USA, Inc.) is developing a 50 MWe-class steady-state helical fusion reactor, which is a kind of stellarator called heliotron composed of two continuous helical coils similar to the large helical device and is operated without plasma current. HESTIA plays the role of the fusion pilot plant. The first-of-a-kind fusion power plant that would follow HESTIA will be a 100 MWe-class steady-state helical fusion reactor. After more than one year of continuous operation, maintenance will be completed within 3 months, aiming for an availability larger than 80%. High-temperature superconducting magnet coils are adopted to generate 8 T of the magnetic field at the helical coil center. HESTIA is a deuterium-tritium fusion reactor, where tritium is self-produced using liquid metal blanket systems. The first wall of the liquid metal blanket including the divertor strike zone is covered and protected by liquid metal free-surface flow, and therefore, individual divertor systems are not required in HESTIA. Electron cyclotron heating is adopted for plasma heating. Since plasma current drive is not required, HESTIA can be operated at a low fusion gain of ∼13, and steady-state operation is principally possible on the order of a year. After a few years of individual development phases, a prototype device is planned to be constructed and operated for the integrated demonstration before starting the construction of HESTIA.

The Saga of Sudden Sam: The Rise, Fall, and Redemption of Sam McDowell by Sam McDowell and Martin Gitlin

Reviewed by: The Saga of Sudden Sam: The Rise, Fall, and Redemption of Sam McDowell by Sam McDowell and Martin Gitlin David Bohmer Sam McDowell with Martin Gitlin. The Saga of Sudden Sam: The Rise, Fall, and Redemption of Sam McDowell. Lanham, MD: Rowman & Littlefield, 2022, 171 pp. Cloth, $26.95. As a teenager residing in suburban Cleveland in the early 1960s I remember Sam McDowell as the great young hope for the future success of the Indians. In effect, he would be the next Herb Score, a southpaw strikeout artist who could return the ball club to its glory days of the 1950s. It didn’t happen. There were flashes of brilliance. McDowell often led the league in strike-outs, was frequently named to the All- Star team, and once even won twenty games. Yet he always seemed to fall short of expectations. I even recall a professor in graduate school alleging McDowell had been satisfied just knowing he could have been great. While a solid pitcher with Cleveland, his career went downhill after he was traded, never coming close to his earlier years. Reliving that history, the book did not disappoint me, since it also explained why McDowell had never reached his potential, and his career ultimately fell apart. At the same time, that explanation— his problems with alcohol— keeps this from being categorized as just a baseball book. It is the story of a very talented athlete with exceptional potential doomed not to reach it. That athlete could have been from any sport, but it so happened McDowell excelled at baseball. [End Page 138] Along with that talent, he was a narcissist who suffered from depression. Although he excelled at sports and academics in high school, nothing seemed to fulfill him personally. While his baseball skills did not, he eventually discovered that alcohol would. Drinking was not uncommon for ballplayers, but for one with McDowell’s other problems it became a crutch. It also slowly affected his performance and family. Ultimately, it ended his baseball career as well as his first marriage. It didn’t help that the Indians lacked a supportive structure for him both on and off the field in the 1960s. By the time he was traded to the Giants, he was well on the way to failure. However, this is also a book about redemption. Joining Alcoholics Anonymous and adhering to its program, McDowell was ultimately able to control his addiction. It also led him to a new life as a counselor for ballplayers suffering from alcohol and drug abuse. He worked for years with two major league clubs, also counseling former players suffering from addictions. While his own rehabilitation was too late to save his marriage, it did turn around his relationship with his children and helped lead to what has truly been a productive life after his playing career ended. In many regards, McDowell has accomplished far more in his life than had he been a Hall of Fame talent in baseball. My expertise is not in counseling, psychology, or alcoholism, so it’s hard to disagree with the authors’ assessments in those areas. As a student of baseball I can question McDowell’s opinion that the 1968 Indians’ pitching staff may have been one of the best— solid, yes, but great, doubtful. I also would submit that the change in the strike zone before the 1963 season had more impact on pitching dominance in the ’60s than did the higher pitcher’s mound. But those are minor quibbles. This is both an interesting and a rewarding read, a story of someone finding true purpose and success after having come close to hitting rock bottom. McDowell was good at baseball but much better at his later pursuits once alcohol was no longer his crutch. Copyright © 2023 University of Nebraska Press

Poka Yoke Meets Deep Learning: A Proof of Concept for an Assembly Line Application

In this paper, we present the re-engineering process of an assembly line that features speed reducers and multipliers for agricultural applications. The “as-is” line was highly inefficient due to several issues, including the age of the machines, a non-optimal arrangement of the shop floor, and the absence of process standards. The assembly line issues were analysed with Lean Manufacturing tools, identifying irregularities and operations that require effort (Mura), overload (Muri), and waste (Muda). The definition of the “to-be” line included actions to update the department layout, modify the assembly process, and design the line feeding system in compliance with the concepts of Golden Zone (i.e., the horizontal space more ergonomically and easily accessible by the operator) and Strike Zone (i.e., the vertical workspace setup in accordance to ergonomics specifications). The re-engineering process identified a critical problem in the incorrect assembly of the oil seals, mainly caused by the difficulty in visually identifying the correct side of the component, due to different reasons. Convolutional neural networks were used to address this issue. The proposed solution resulted to be a Poka Yoke. The whole re-engineering process induced a productivity increase that is estimated from 46% to 80%. The study demonstrates how Lean Manufacturing tools together with deep learning technologies can be effective in the development of smart manufacturing lines.

Prediction of deposition bead geometry in wire arc additive manufacturing using machine learning

The deposition bead geometry in the arc strike zone is often abnormal compared with that in the middle deposition zone. The accumulation of these errors in the deposition process results in defects in the overall geometry of the deposition bead. To prevent the accumulation of such errors, this study aimed to address the irregular deposition bead shape and deviation of the deposition bead geometry in the arc strike zone without changing the deposition path or introducing external devices. A support vector machine classifier, which is a typical application of machine-learning classification models, was used to obtain the deposition condition ranges for a uniform deposition bead shape. The deposition conditions of the arc strike and middle deposition zones that could reduce the deviation of the deposition bead geometry in the arc strike zone were obtained using support vector machine regression. These conditions were applied in the form of variable conditions in single-path deposition. Five-layer deposition was conducted to validate the regression model. As a result of the validation experiment, the average height and width errors in the arc strike zone were 0.36% and 1.28%, respectively, and the average height and width errors in the middle deposition zone were 0.64% and 1.26%, respectively. Therefore, the regression model can be used for accurate deposition, thereby reducing the post-processing cost.

The Statistical, Scientific, and Sensory Proof of Teddy Ballgame’s Mammoth Shot

The Statistical, Scientific, and Sensory Proof of Teddy Ballgame’s Mammoth Shot Larry Ruttman (bio) For a large segment of the Red Sox Nation, the horrendous 1883 explosion of Krakatoa in Indonesia, which killed over thirty-five thousand people, pales by comparison to the storm stirred up and still continuing about Ted Williams’s mammoth home run struck in 1946 at Fenway Park in Boston. The main reason seems to be that no one looking at the lonely red seat high in the right-field bleachers marking where the ball landed can believe a baseball can be hit that far, including Ian Kinsler, but we’ll get to that. I was fifteen in 1946, an avid Red Sox and Splendid Splinter fan, and lucky to be seated in the center-field bleachers on June 9 with a sideways view of Ted’s man-made volcano. I guess you had to be there. In the seventy-five years since then, all those people and personages whom I have told about the event have cast a dubious eye on me and my story, including such notables as Theo Epstein and the aforementioned Ian Kinsler. That is, until I became acquainted lately with Chaim Bloom, the present chief baseball officer of the Red Sox, who read my account of the home run (about which you will read) in my 2018 short memoir, “My Eighty-Two Year Love Affair with Fenway Park: From Teddy Ballgame to Mookie Betts.” Chaim wrote to me, “I must admit I was a skeptic myself, but I believe you.” Hey, I believe in this guy whose Yale University– and Tampa Bay Rays– enhanced smarts will lead the Boston Red Sox to nirvana yet again. I am supposing Chaim was persuaded by the wealth of facts I recited in the subsequent long quote from the memoir. One would have to be more Machiavellian than Machiavelli to make this stuff up. Here is my account. I’ll supply even more facts from my own memories of the event. God forbid that I should be labeled “More Machiavellian than Machiavelli”: In 1946 the Boston Red Sox won the American League pennant in a romp. It might be said that Ted Williams’s career rose to an apogee and [End Page 17] descended to its perigee that summer. Perhaps the apogee was on June 9, 1946, by which time the Sox were all alone in first place and Ted led the league in every major batting category. Accompanied again by my good friend then and now, Yale Altman, rifle armed all-city third baseman for English High School in Boston, I attended a doubleheader between the Sox and the Detroit Tigers. In the first game, Ted hit a soaring home run off the screen at the back of the Red Sox bullpen off ace Detroit curve-ball specialist Tommy Bridges. But the best was yet to come in the nightcap on this beautiful June day when the west wind was briskly blowing from home plate out to right field. Ted stepped in against Detroit’s fine right hander (and later a respected manager) Freddy Hutchinson. I can see and hear it all clearly in my mind’s eye and ear. The pitch was thrown hard and to the inside. Ted’s quick bat flashed through the strike zone striking the ball so hard that a sharp crack was heard all over Fenway Park. Indeed, the ball rose high and fast describing a relatively flat arc in the sky, more like a gargantuan line drive than a big fly. The ball sailed and sailed, landing very high in the sixty or so row right field bleachers. From my position in the center field section of the bleachers I saw the ball come down and quickly bounce up to the very last rows of the bleachers, close to six hundred feet away from home plate and thirty-five or more feet off the ground. As reported in the newspapers the next day, what actually happened is that the ball went through a man’s straw hat in the 42nd row, bouncing off his head to the position I just described. That man was 502 feet...

Both prey and predator features predict the individual predation risk and survival of schooling prey.

Predation is one of the main evolutionary drivers of social grouping. While it is well appreciated that predation risk is likely not shared equally among individuals within groups, its detailed quantification has remained difficult due to the speed of attacks and the highly dynamic nature of collective prey response. Here, using high-resolution tracking of solitary predators (Northern pike) hunting schooling fish (golden shiners), we not only provide insights into predator decision-making, but show which key spatial and kinematic features of predator and prey predict the risk of individuals to be targeted and to survive attacks. We found that pike tended to stealthily approach the largest groups, and were often already inside the school when launching their attack, making prey in this frontal 'strike zone' the most vulnerable to be targeted. From the prey's perspective, those fish in central locations, but relatively far from, and less aligned with, neighbours, were most likely to be targeted. While the majority of attacks were successful (70%), targeted individuals that did manage to avoid being captured exhibited a higher maximum acceleration response just before the attack and were further away from the pike's head. Our results highlight the crucial interplay between predators' attack strategy and response of prey underlying the predation risk within mobile animal groups.

Relationships Among Shoulder Rotational Strength, Range of Motion, Pitching Kinetics, and Pitch Velocity in Collegiate Baseball Pitchers.

Cross, JA, Higgins, AW, Dziuk, CC, Harris, GF, and Raasch, WG. Relationships among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate baseball pitchers. J Strength Cond Res 37(1): 129-135, 2023-Throwing shoulder injuries are the most common type of injury experienced by baseball pitchers. Weakness in the shoulder musculature and insufficient throwing arm range of motion are both risk factors for developing a shoulder injury. The goal of this study was to determine correlations among shoulder rotational strength, range of motion, pitching kinetics, and pitch velocity in collegiate pitchers. Thirteen uninjured male college pitchers were evaluated. Clinical measures included shoulder internal and external rotation range of motion, peak isokinetic internal and external rotator strength, and peak isometric internal and external rotator strength. Three-dimensional biomechanics were assessed as subjects threw from an indoor pitching mound to a strike zone net at regulation distance. Pearson's correlations were used to assess the associations among the clinical measures and throwing metrics. Five significant correlations were found between peak shoulder compressive force and strength, and 4 significant correlations were found between pitching velocity and strength ( p < 0.05). No significant correlations were found between range of motion and pitching kinetics or velocity. Our results suggest that as shoulder rotational strength increases, the peak shoulder compressive force and pitch velocity both increase. Knowledge of relationships between strength metrics and pitching biomechanics may allow for improved strength training routines with the goal of increasing velocity without increasing injury risk.

More Elevated Fastballs Associated With Placement on the Injured List due to Shoulder Injury

PurposeTo evaluate whether impending shoulder injury was associated with changes in pitch location or velocity immediately preceding injury.MethodsPitchers placed on the injured list (IL) due to a shoulder injury between 2015 and 2020 were identified in the Major League Baseball transactions database. Four-seam fastball velocity and frequency of pitch location for each pitch type was collected for each player in the season before placement on the IL and within 1 month of placement on the IL with a minimum of 55 pitches thrown of 1 type. Pitch locations were collected as identified by Baseball Savant’s Game-Day Zones. Game-Day Zones were consolidated into high (above the strike zone midpoint) versus low, arm side (closer to the pitcher’s arm side of the plate) versus opposite side, and within the strike zone versus out of zone. Repeated measures analysis of variance determined differences in four-seam velocity and the location distribution of 4-seam fastballs, change-ups, and breaking balls among each group.ResultsIn total, 267 pitchers were placed on the IL for a shoulder injury with the majority diagnosed with inflammation (89/267) followed by strain or sprain (69/267). Four-seam fastball locations significantly increased above the mid-point of the zone (45.9% vs 42.4%, P = .008) and out of the strike zone (48.5% vs 46.5%, P = .011) within a month before IL placement. There was no significant change in 4-seam fastball velocity immediately before IL placement.ConclusionsPitchers threw more elevated 4-seam fastballs and out-of-zone 4-seam fastballs in the month before IL placement for shoulder injury. These findings suggest that a loss of 4-seam fastball command decreases with impending shoulder injury.Level of EvidenceIV, prognostic case series.

Segment power analysis of collegiate softball hitting

ABSTRACT The primary aim of this investigation was to describe the energy flow through the kinetic chain during softball hitting using a segmental power analysis. Twenty-three NCAA Division I collegiate softball athletes (20.4 ± 1.7 yr; 166.7 ± 22.0 cm; 74.9 ± 15.9 kg) performed three maximum effort swings off a stationary tee placed in the middle of the strike zone. Pelvis, trunk, humerus, forearm and hand segment powers were integrated across four phases of the softball swing (load, stride, acceleration, and follow-through). The load and stride phases had low segment energy inflow and outflow values as well as net segment energy flow for all body segments compared to subsequent phases of the swing. The acceleration phase showed large trunk inflow values relative to the pelvis. There was also descriptively larger front compared to back-side upper extremity inflow. Finally, the follow-through phase showed primarily energy outflow for the upper extremity segments likely attributed to slowing down rotation.

Divertor detachment in the pre-fusion power operation phase in ITER during application of resonant magnetic perturbations

Detachment of the divertor plasma during application of resonant magnetic perturbation (RMP) fields is evaluated for hydrogen H-mode plasma during the first pre-fusion power operation (PFPO-1) phase in ITER by 3D plasma boundary modelling with EMC3–EIRENE. Plasma response effects from a linearized, resistive, single fluid MHD model are discussed, which includes partial screening of the externally applied field—but also field amplification near the separatrix. This field amplification is found to play a pivotal role for the magnetic footprint on the divertor targets, but is sensitive to model parameters. Extensions of the footprint beyond the straight portions of the ITER vertical divertor targets, optimized for high stationary heat flux handling, may be possible depending on the level of toroidal rotation in the plasma. Exhaust from the bulk plasma is guided by the helical corrugations (lobes) of the perturbed separatrix, and this results in an upstream heat flux that is distributed over these lobes with lower peak values than in the typical radial heat flux profiles seen in the absence of magnetic perturbations. As a consequence, an earlier onset (with respect to the upstream density) of detachment is found in the traditional strike zone when RMPs are applied, but secondary, non-axisymmetric strike locations appear—and those remain attached at temperatures above 10 eV. Neon seeding can mitigate these non-axisymmetric heat loads, but this becomes less efficient for large magnetic footprints.

Volumetric recombination in EMC3-EIRENE: Implementation and first application to the pre-fusion power operation phase in ITER

An upgrade to the 3D plasma boundary model EMC3-EIRENE for detached divertor plasmas is introduced and evaluated. Stabilization of the iterative approximation of a self-consistent plasma–neutral gas solution is required at low divertor plasma temperatures, and this has been achieved by linearization of the energy loss term associated with the electron–neutral gas interaction. An implicit method for volumetric recombination has been implemented, which improves agreement with SOLPS-ITER results for the pre-fusion power operation phase in ITER. Resonant magnetic perturbations for control of edge localized modes are found to result in a partially detached divertor plasma with a significantly broader reduction of particle loads in the traditional strike zone, which is attributed to volumetric recombination. The additional non-axisymmetric far scrape-off layer strike points, on the other hand, remain attached at relatively high temperature so that volumetric recombination is not effective there.

Direct measurement and modeling of intraglottal, subglottal, and vocal fold collision pressures during phonation in an individual with a hemilaryngectomy.

The purpose of this paper is to report on the first in vivo application of a recently developed transoral, dual-sensor pressure probe that directly measures intraglottal, subglottal, and vocal fold collision pressures during phonation. Synchronous measurement of intraglottal and subglottal pressures was accomplished using two miniature pressure sensors mounted on the end of the probe and inserted transorally in a 78-year-old male who had previously undergone surgical removal of his right vocal fold for treatment of laryngeal cancer. The endoscopist used one hand to position the custom probe against the surgically medialized scar band that replaced the right vocal fold and used the other hand to position a transoral endoscope to record laryngeal high-speed videoendoscopy of the vibrating left vocal fold contacting the pressure probe. Visualization of the larynx during sustained phonation allowed the endoscopist to place the dual-sensor pressure probe such that the proximal sensor was positioned intraglottally and the distal sensor subglottally. The proximal pressure sensor was verified to be in the strike zone of vocal fold collision during phonation when the intraglottal pressure signal exhibited three characteristics: an impulsive peak at the start of the closed phase, rounded peak during the open phase, and minimum value around zero immediately preceding the impulsive peak of the subsequent phonatory cycle. Numerical voice production modeling was applied to validate model-based predictions of vocal fold collision pressure using kinematic vocal fold measures. The results successfully demonstrated feasibility of in vivo measurement of vocal fold collision pressure in an individual with a hemilaryngectomy, motivating ongoing data collection that is designed to aid in the development of vocal dose measures that incorporate vocal fold impact collision and stresses.

Study on the optimal position of the roof low roadway based on the response surface methodology

For determine the optimum position of the roof low roadway, the optimal solution is derived according to the response surface methodology. The UDEC numerical simulation of the overburden gives the porosity distribution of the strike fractured zone, the upper limit heights of the caving zone and the fractured zone are obtained as 18 m and 65 m, respectively. Based on the porosity distribution, the FLUENT numerical models of the goaf zone, air inlet roadway, air return roadway, working face and roof low roadway were established to simulate the gas concentration in the upper corner and gas drainage volume in roof low roadway during mining. Using the vertical and horizontal distance of the roof low roadway as the influencing factors, the experimental scheme of the position of the roof low roadway was designed according to the response surface method, and the response values were obtained from the FLUENT simulation experiments, predicting that the vertical and horizontal distances of the roof low roadway were 7.7 m and 5.9 m respectively when the interaction between the gas concentration in the upper corner and gas drainage volume in roof low roadway was optimal. Field tests showed that the average gas concentration in the upper corner and the average gas drainage volume in roof low roadway were 0.432% and 40.861 m3/min respectively, both of which were less than 10% of the error from the simulations. The design of the roof low roadway has effectively managed the gas accumulation problem in the upper corner.