Organ Pipe Research Articles

Theoretical investigation of the excitation of leaky modes for multilayered models

SUMMARY The dispersion analysis with array-based methods enables us to detect and analyse the multimode dispersive waves with weak amplitudes. Over the past years, there has been widespread extraction of higher normal modes from earthquake records and ambient noise, which have been extensively employed in near-surface and crustal investigations. Notably, the frequent reporting of leaky modes in recent observations has gained significant attention. This is because leaky modes can provide more constraints on subsurface structures. Particularly, a subset of leaky modes is found to be sensitive to P-wave velocities, which has the potential to compensate for the limitations of traditional surface wave inversion. Nevertheless, due to the lack of knowledge of the excitation and practical application of leaky modes, it is urgent to have an effective guide in selecting certain leaky modes for practical inversion combined with other imaging methods. To this end, the theoretical investigation into the excitation of leaky modes for multilayered models is undertaken. By computing theoretical seismograms for various source mechanisms and source depths with the discrete wavenumber and the normal-mode summation methods, respectively, the qualitative evaluation of the leaky-mode contributions to the synthesized seismograms is conducted. Additionally, the impact of the source depth for the same source mechanism is meticulously examined by the dispersion spectra. Furthermore, with the accurate computation of leaky modes, we categorize the leaky modes into PL and OP (organ-pipe) modes according to their distinctive properties, that is, their attenuation and eigen-displacements, which may be used to explain very well the occurrence of certain leaky modes on the dispersion spectrum and be indicative of the reasonable choice of PL modes to put them into practical inversion for P-velocity structures.

Representations of Music and the Dance in Late Roman Art

Music and the dance are an important theme represented in various artistic media of the Late Roman and Early Byzantine periods, including mosaic pavements and decorative arts such as silver metalwork, woven textiles, and carved ivories. A popular aspect of this theme is imagery of the Dionysiac thiasos, with members of the wine god’s entourage making merry by dancing and sounding crotala or cymbal tongs, as we see in a fragmentary mosaic from the House of the Dionysiac Thiasos at Augusta Traiana – Beroe. A similar effect occurs in either an expanded or a somewhat reduced format in pavements from Argos and Madaba. Besides mosaics, this subject also appears on Late Antique silver plate made for display, such as objects in the Mildenhall Treasure from Roman Britain and related works. Coptic textiles used to ornament private houses as colorful wall hangings feature lively dancers and musicians, and these figures may or may not have a mythological identity. Other non-mythological representations of music and the dance appeared in domestic and public settings. An outstanding example is the well-preserved Mosaic of Female Musicians that decorated a house in Mariamin, Syria, and that assembles an impressive group of instrumentalists and a dancer. One observes a pipe organ (hydraulis) along with a cithara, an aulos, and an acetabulum, consisting of a series of metal bowls struck with a baton. Elsewhere there are depicted a pantomime performance with an organ accompaniment, visible in a mosaic from Noheda, Spain, as well as music-making and dancing in the context of the circus. The latter subject appears on a consular diptych, and on the base of the Obelisk of Theodosius in Constantinople. We finally note that the pipe organ was later adopted for use in the church liturgy, reflected in an illustration in the Utrecht Psalter of 9th-century date. If the latter work of art is a copy of a Late Antique manuscript, as some scholars believe, then the pipe organ’s adoption for Christian ceremonial practice should be dated earlier than originally thought.

Study of phenanthrenes from their unique mass spectrometric behavior through quantum chemical calculations to liquid chromatographic quantitation

Phenanthrenes and their derivatives have biological relevance owing to their antimicrobial, antioxidant, and cytotoxic effects on cancer cells. They can be efficiently analyzed through ultrahigh-performance liquid chromatography coupled to tandem high-resolution mass spectrometry (UHPLC–MS/HRMS). Herein, we first studied the unique fragmentation behavior of phenanthrenes based on direct infusion MS/HRMS analysis. As a newly described phenomenon, “organ pipe distribution”, we found a structural connection linking their unique fragmentation pattern to serial H radical losses. The bonds responsible for this behavior were identified through quantum chemical calculations using a stepwise approach. Furthermore, the chromatographic aspect of this study was enhanced by developing, validating, and applying a new unscheduled targeted UHPLC–MS/HRMS method for quantifying phenanthrenes in Juncus compressus herb. Targeted compounds were efficiently separated within 4 min upon utilizing the Accucore C30 column, and the unscheduled targeted analytical approach afforded five new isomers. Compounds 1 (effususol), 3 (dehydroeffusol), and 6 (7-hydroxy-1-methyl-2-methoxy-5-vinyl-9,10-dihydrophenanthrene) had their linearity limits determined within 10–5000 nM, and Compounds 2 (effusol), 4 (juncusol), 5 (effususin A), and 7 (compressin A) within 25–5000 nM. The coefficients of variation for precision ranged from 1.4 % to 15.2 %. The obtained matrix effects and accuracy values were also within acceptable ranges. Compounds 2 (effusol) and 3 (dehydroeffusol) were present in both methanolic and dichloromethanolic extracts of Plants 1 and 3 at the highest concentrations. Furthermore, the relationship between phenanthrene fingerprints, obtained through ANOVA statistical analysis of quantitative data, and the geographical location of herbs was also established.

"Before His Head was Cold": Puritan Piety and the Pipe Organ

It is well known that musical activity in colonial New England was quite low; this was in no small part caused by the Puritan emphasis on the unaccompanied singing of psalms in their churches. What is often neglected when discussing Puritan musical activity is how Calvinism’s grip on Puritan theology loosened throughout the seventeenth and eighteenth centuries, leaving room for changes to worship traditions. The same Puritans who destroyed pipe organs across England in the seventeenth century started building these instruments in their New England meeting houses towards the end of the eighteenth century. This paper uses primary sources to compare the Puritan theology of the Westminster Confession to statements of belief from Boston’s most progressive Congregationalist churches in the late eighteenth century. Such comparisons, when paired with a timeline of rhetoric surrounding instruments in worship music, connect doctrines of separation to the destruction of organs and doctrines of unity to the reinstatement of organs.

A Two-Way Choice: The Medieval Pipe Organ and the Development of Medieval Church Music

The pipe organ during the medieval period played a significant role in religious ceremonies and worship. During this time, the pipe organ was the primary instrument used in churches and cathedrals across Europe. Organ music of the medieval period was characterized by its solemnity, grandeur, and religious significance. This paper explores the intricate relationship between the medieval pipe organ and the development of church music during the medieval period. It examines the historical background, construction, religious significance, and evolution of the pipe organ alongside medieval church music and music education. This paper discusses the symbiotic connection between the advancement of the pipe organ and the education in medieval church music, highlighting the role of cultural, historical, and socio-political factors in shaping this relationship. Additionally, it explores the significance of the "Codex Faenza," a renowned collection of medieval instrumental works, in understanding the interplay between the pipe organ and medieval religion. Overall, the abstract underscores how the pipe organ served as more than a musical instrument; it acted as a cultural symbol, facilitating identity expression, cultural exploration, religious dissemination, and the display of power in medieval Europe.

Identifikasi Konsep Fisika pada Kearifan Lokal Kesenian Tongklek di Indonesia

Indonesia is a country with cultural diversity that has been passed down from generation to generation. One of these cultures is the Tongklek art originating from Tuban Regency, East Java. In Tongklek art, all musical instruments used can be associated with the application of physics concepts. However, due to limited human resources, the study of the physics concepts contained in the art of Tongklek has received little attention. This study aims to identify the concept of physics in the local wisdom of Tongklek in order to increase public knowledge. In this study using a descriptive research method with a qualitative approach. The analysis technique used is data reduction. Based on the results of the research, it was found that the Tongklek art is a type of traditional art in the form of music art found in Tuban Regency, East Java. Tongklek art is a type of art in which there are several musical instruments, among the musical instruments used are kentongan, xylophone, bonang/kenong, gong suwuk, blunt gong, gong jengur/jegluk, drums, and plastic drums. In every musical instrument in the Tongklek art there is a concept of physics, namely the material of sound waves, especially organ pipes. The source of the sound of the Tongklek art, on average, comes from musical instruments that have a certain volume, there are forms where all fields are closed, there are also some of these things which are named as air columns as the source of the vibrations.

Pipe Organ Design Including the Passive Haptic Feedback Technology and Measurement Analysis of Key Displacement, Pressure Force and Sound Organ Pipe

In this work, an organ pipe instrument with a mechatronic control system including the Passive Haptic Feedback technology is implemented. The test bed consists of a motorized positioning stage mounted to a brace that is attached to a bridge on a platform. A simple pneumatic mechanism is designed and realized to achieve the same dynamics pressure for each measurement attempt on the keyboard. This system contain pipes, an air compressor, valves, and a piston connected to applied force pressure on the keyboard of the organ pipe. The pneumatic components, like valves and pressure regulators, mounted on the profile plate are connected to the main air supply line via flexible tubing or hoses to the air compressor and mechanical trucker. The pneumatic system has many types of valves that regulate the air speed, air flow, and power. The combination of valves and air compressor control the air flow and the mechanism of piston and pressure on the keyboard. The mechanical actuator presses the key to be tested, and a load cell detects the applied key force. A laser triangulation measurement system based on a Laser Displacement Sensor measures the displacement of the key during the key depression. The velocity of the key motion is controlled by the pneumatic actuator. A miniature-sized strain gauge load cell, which is mounted on a musical keyboard key, measures the contact force between the probe and the key. In addition, the quality of the audio signal generated by the organ instrument is estimated using the Hilbert transform.

Sounding Mechanism of a Flue Organ Pipe-A Multi-Sensor Measurement Approach.

This work presents an approach that integrates the results of measuring, analyzing, and modeling air flow phenomena driven by pressurized air in a flue organ pipe. The investigation concerns a Bourdon organ pipe. Measurements are performed in an anechoic chamber using the Cartesian robot equipped with a 3D acoustic vector sensor (AVS) that acquires both acoustic pressure and air particle velocity. Also, a high-speed camera is employed to observe the jet coming out from the windway. For that purpose, the steam resulting from dry ice and hot water is used. A numerical simulation of the sounding mechanism of a pipe of the same geometry is based on measuring the pressure signal and the intensity field around the mouth employing an intensity probe and visualizing and observing the motion of the air jet, which represents the excitation mechanism of the system. The ParaVIEW software serves for the simulation and visualization of the air jet. Then, the results obtained from measurements and simulations are compared and discussed. Also, some future directions discussing the application of a machine-learning approach to the area of pipe organ air flow investigation are contained in the Conclusions section.

Optimization of Composite Cavitation Nozzle Parameters Based on the Response Surface Methodology

Cavitation is typically observed when high-pressure submerged water jets are used. A composite nozzle, based on an organ pipe, can increase shear stress on the incoming flow, significantly enhancing cavitation performance by stacking Helmholtz cavities in series. In the present work, the flow field of the composite nozzle was numerically simulated using Large Eddy Simulation and was paired with the response surface method for global optimizing the crucial parameters of the composite nozzle to examine their effect on cavitation behavior. Utilizing peak gas-phase volume percent as the dependent variable and the runner diameter, Helmholtz chamber diameter, and Helmholtz chamber length as independent variables, a mathematical model was constructed to determine the ideal parameters of the composite nozzle through response surface methodology. The optimized nozzle prediction had an error of only 2.04% compared to the simulation results, confirming the accuracy of the model. To learn more about the cavitation cloud properties, an experimental setup for high-pressure cavitation jets was also constructed. Impact force measurements and high-speed photography tests were among the experiments conducted. The simulated evolution period of cavitation cloud characteristics is highly consistent with the experimental period. In the impact force measurement experiment, the simulated impact force oscillates between 256 and 297 N, and the measured impact force oscillates between 260 N and 289 N, with an error between 1.5% and 2.7%. The simulation model was verified by experimental results. This study provides new insights for the development of cavitation jet nozzle design theory.

Measuring the behavior of the acoustic standing wave exiting a flue organ pipe: Is the decay sinusoidal or exponential?

Correctly predicting the playing frequencies of a musical instrument is dependent on the length of the resonator with the addition of an end correction. There are multiple theories describing this end correction, perhaps the simplest being that the end correction of a pipe is a physical extension of the sinusoidal pressure standing wave inside the pipe. However, recent optical imaging of the flow in a flue organ pipe found an unexpected exponential decay of pressure just outside of the pipe. This work looks to validate those findings acoustically. A flue organ pipe was played at the 1st, 5th, and 7th harmonics and the pressure just inside and immediately outside the end of the pipe played was measured using a zero-degree PU Match Microflown sound intensity probe. These measurements were fit to both exponential and sinusoidal curves and compared to the optical images. While an exponential trend is in fact apparent in some cases, the goodness-of-fit appears to be dependent on which harmonic is sounding. Future work includes exploration of a potential transitional region, assessing the impact of altered pipe geometry (both cross-sectional shape and size), and investigating potential sensor interference by using other measurement equipment.

Structure Design Of ROV-Based MOPU Platform Pin Hole Spin Cleaning Device

The pile legs of the MOPU platform have been submerged in seawater for a long time, and there are a large number of Marine organisms on the surface, which has a negative impact on the stability of the platform and needs to be cleaned regularly. Most of the existing jacket cleaning technologies are aimed at cleaning the outer surface, and there are few studies on cleaning the Marine organisms attached to the pin holes of the pile legs of MOPU platform. In order to solve the above problems, this paper firstly designs a spin-type pin hole cleaning device based on underwater wall-climbing robot by drawing lessons from domestic and foreign experience. At the same time, the Fluent simulation of three commonly used cavitation water jet nozzles is carried out, and the most suitable nozzle type for pin hole cleaning is selected from the organ pipe type, shear type and corner cavitation nozzles. In the actual operation, the water temperature and depth around the ROV are changing, so the simulation needs to consider the influence of temperature and depth changes. In this paper, a reasonable point is put forward for the structural design of the spin cavitation cleaning device. The simulation results show that the corner cavitation nozzle should be selected in the pinhole cleaning operation.

CFD analysis of thermal fluid dynamic parameters inside an organ pipe: influence of air temperature variations

Organ pipes represent a fluid-dynamic challenge since the time of Bernoulli and Reynolds. A complete and reliable description of the fluid behaviour at the basement of the resonator named the “mouth” of the pipe is still absent. In the context of the design of an air-heating system for the attenuation of the inconsistencies between sounding frequencies of organ pipes, computing efforts were carried out focusing on the fluid-dynamic behaviour of the air at the mouth of the pipe at different temperature conditions. Describing the air dynamic and the heat transfer at the mouth level of the pipe, it would be possible to predict the heating conditions within the pipe resonator, which was the main subject of the project. Multiple points on the pipe organ air blowing scheme were considered for simulation results extraction. Temperature, pressure, and audio measurements were performed and no significant influence of the temperature on those parameters was raised from measurements, rising questions about the effective behaviour of the blowed air at the mouth of the pipe. Simulations were performed to predict both the fluid dynamic and the heat transfer. A finite volume approach in Fluent environment was chosen. The SST k-omega model was considered in reliability vs computation time balance. 3D simulations were performed based on a CAD reconstructed model of a real pipe. The results of the simulations confirmed experimental data, and they may prove the absence of a significant mass exchange between the in and outside of the mouth of the pipe. The oscillation of the air membrane at the mouth of the pipe may be cleared from instabilities and turbulence regime phenomena, as usually described in the literature.

Z dziejów wielkopolskiego organmistrzostwa — życie i działalność Józefa Gryszkiewicza (1840–1901)

Organ building and pipe organs in Poznań and Greater Poland is a subject that is still waiting for thorough investigation. This article investigates the musical history of Poznań and presents one of the city’s greatest organ builders: Józef Gryszkiewicz. Gryszkiewicz made nearly a hundred instruments—around half of which have survived until the present day. Additionally, he renovated several dozen organs, prepared expert opinions, assessed the work of other organ builders, translocated instruments, and educated generations of apprentices. So far, little has been known about his life and work, including even the most important facts of his life. The article focuses on three fundamental aspects: it presents his biography, describes the nature and the unique character of his trade, and provides a list of his works.

Numerical study on role of foot of a flue organ pipe: relative phases in oscillations among pipe, foot and jet

Recent numerical studies showed that the foot of flue organ pipes closed at one end acts as a Helmholtz resonator and influences the acoustic oscillation in the pipe. Namely, the relative phase of oscillations between the pipe and foot changes depending on the resonance frequency of the foot. This fact can be explained by the theory of forced harmonic oscillators, in which the pipe works as a force driving the foot. However, in the damping-controlled regime, in which the resonance frequency of the foot, fH, is nearly equal to the frequency of acoustic oscillation, fa, the amplitude of the acoustic oscillation is smaller than those in the mass-controlled regime fH < fa and the stiffness-controlled regime fH > fa, even though the pressure oscillation in the foot lags behind that in the pipe by π/2. In this paper, to investigate this problem and to explore the role of the foot in detail, using a three-dimensional model of a closed flue organ pipe, we numerically investigate the relative phases among the pressure oscillation in the pipe, that in the foot and the jet velocity. We conclude that total balance among them is crucial for sustaining acoustic and fluid oscillations in the sound generation process. The oscillating jet drives the pipe with appropriate timing to sustain the acoustic oscillation for the stiffness-controlled and mass-controlled regimes. In contrast, the jet inefficiently drives the pipe with inappropriate timing for the damping-controlled regime.

Study of Quality and Damping Factor at First and Second Resonance of Closed Organ Pipe

The quality factor is a dimensionless physical quantity related to the damping factor present in the medium. The sound is recorded from the resonance tube experiment at the first and second resonating lengths. It is analyzed by PRAAT software to calculate the quality and damping factor. The quality factor varies from 12.50 to 146.70 and 6.32 to 130.95 at first and second resonant length respectively. In case of damping factor, it varies from 3.50x10−3 to 40.00x10−3 and 3.82 x10−3 to 79.11x10−3 at respective first and second resonating length. The ratio of the quality factor of the second resonance to that first resonance varies from 0.49 to 0.97 and for the damping factor that ratio varies from 1.02 to 2.02. The quality factor is higher at the first resonating length than at the second resonating length. The damping factor is lower in the first resonating length than in the second resonating length. From the experiment on the closed organ pipe, it was found that the system is under-damped due to the damping factor of less than one. At the first and second resonating lengths the relation between quality and damping factor is inversely nature.

Improve critical thinking skills using traditional musical instruments in science learning

Experiment activity is an essential part of science learning. <em>Suling </em>(flute), a traditional musical instrument from West Java, can be used as a learning media for sound wave concepts. Technology-based mobile can be used as an experimental tool is <em>Phypox</em>. This study aims to report using a combination of <em>Suling</em> and <em>Phypox</em> in experiment activities. The designed activity aims to engage students in critical thinking. The instrument for measuring critical thinking consists of five questions based on the critical thinking aspect: interpretation, analysis, evaluation, inference, and explanation. The study used a one-group pre-and post-test design on 32 8th-grade students at one of the junior high schools in West Java Province, Indonesia. The study procedure is a pre-test, discussion of <em>Suling</em>’s concepts, introduction to <em>Phypox</em> application, experiment activity, presentation, and post-test. Data analysis uses the normalized gain to compare the pre-and post-test. Experiment activities help students to understand frequency, open organ pipes concepts, and investigate the speed of sound produced by <em>Suling</em>. The study found a significant change in the pre-and post-test scores of students after experimenting, so it could be interpreted that the experimental activities using <em>Suling</em> and <em>Phypox</em> affected critical-thinking students.

Revisiting the Open-End Reflection Coefficient and Turbulent Losses in an Organ Pipe with Low Mach Number Flowipe with low Mach number flow

The reflection coefficient of the open end belongs among the essential parameters in the physical description of a flue organ pipe. It leads directly to practical topics such as the pipe scaling. In this article, sound propagation is investigated inside an organ pipe with the most intense mean flow that is achievable under musically relevant conditions. A theoretical model is tested against the experimental data to obtain a suitable formula for the reflection coefficient when a non-negligible flow through the open end is considered. The velocity profile is examined by means of particle image velocimetry. A fully developed turbulent profile is found and interactions of the acoustic boundary layer with the turbulent internal flow are discussed. A higher value of the end correction than expected from the classical result of Levine and Schwinger is found, but this feature shall be associated with the pipe wall thickness rather than the mean flow effects.

Cremated Animal Bone Piles in the Western Papaguería

In 1985 Julian Hayden reported 95 heaps of cremated animal bones in the Sierra Pinacate. For a variety of reasons, he concluded that the practice was long-lived and unique to that area. He attributed it to the Pinacateño Areneños, an isolated band of Areneños (also known as Hia-Ced O’odham or “Sand Papagos”). Fieldwork in Cabeza Prieta National Wildlife Refuge, Organ Pipe Cactus National Monument and the Barry M. Goldwater Range East and West over the last 30 years has located an additional 34 piles of cremated animal bones exactly like those described by Hayden (Figure 1). It is suggested that this practice is indeed long-lived and unique throughout Areneño (Hia-Ced O’odham) territory.

Numerical Investigation of Cavitating Jet Flow Field with Different Turbulence Models

In numerous industries such as drilling, peening, cleaning, etc., a cavitating jet is adopted. However, it is challenging to simulate the cavitating flow field numerically with accuracy. The flow field of the organ pipe cavitation nozzle is simulated in this research using the RNG k−ε, DES, and LES turbulence models. The LES model can more accurately predict the periodic shedding of a cavitating cloud, which is basically consistent with the jet morphology captured with a high−speed camera. The flow pattern, cavitating cloud evolution and shedding period of a cavitating jet are analyzed. The findings demonstrate that the LES model produces a cavitating effect inside the nozzle that is superior to those produced by the RNG k−ε and DES models. The vortex rings in the diffusion section are simulated using the LES model, which accelerates cavitation. The cavitating clouds of the organ pipe nozzle show periodic evolutions, with stages of generation, development, shedding and collapse. The periodic shedding of the cavitating clouds exhibits a similar pattern in the vorticities simulated using the LES model, and the vorticities display the small-scale structures where the cavitating bubbles collapse. This study can provide a reference for the simulation of a cavitating jet and the analysis of the cavitating mechanism.

The influence of thermal-hygrometric properties of air on the tune of pipe-organs

Pipes of pipe-organ dynamically change their tune during the year due to environmental conditions, sometimes consistently, making these instruments hard to be played. Because thermal-hygrometric properties of air change through the seasons, this study investigates the influence of air temperature and relative humidity on pipes' tune by monitoring a real pipe organ during a year. Normalized frequency was introduced to analyze and compare notes and logs of different extents with each other, and a variation within 7% was reported. Absolute Humidity parameter was introduced to gather temperature and relative humidity under a single parameter, allowing the evaluation of the contribution of the relative humidity to the frequency changes. Fitting models and their equations were extracted, and normalized residuals were estimated. The same analyses were performed on a small pipe organ at a laboratory scale to confirm the reliability of those models. A comparison between standard equations for calculating the resonance frequency of pipes and the introduced models is also discussed. Finally, the slight influence of humidity on the sounding frequency was confirmed. K/coefficients were introduced to align the results of the longitudinal resonance frequency equation for cylindrical cavities from literature with the resulting model by comparing the temperature influence.