Laymon N. Miller

Acoustic Filter for Water‐Filled Pipes

It is anticipated that some of the auxiliary equipment to be used in conjunction with the new water tunnel under construction at the Pennsylvania State College will be particularly noisy in the ultrasonic frequency region where certain low level acoustic measurements are to be made. This potentially noisy equipment includes such items as a deaerator, an energy dissipator, and a pressure control system which are located in a water loop, external to the main tunnel section. To effectively isolate this loop acoustically from the remainder of the tunnel where the acoustic measurements will be made, it has been considered desirable to design an acoustic filter which can be inserted at the junctions of the loop with the tunnel. This filter should serve the multiple function of reducing the sound transmission through the pipe walls and through the water in the pipes while permitting the passage of relatively large volumes of water at small loss of pressure. The problem of isolation in the pipe path is a fairly c...

Noise: My 62 years of it!

Imagine getting paid for having fun! Well, in retrospect, it was fun; but there were several tough challenges. Even those are worth remembering. From 1941 to 1982, there were acoustic torpedoes, HVAC acoustics, noise and vibration in auditoriums, aircraft and airport noise, OSHA and industrial noise control, power plants, community noise problems, vbration, railroad and subway vibration control, legal acoustics, noise manuals, and noise courses—and a few other things that don’t fit into those neat categories. Some specific jobs could be named, but that would take away the suspense and the surprise. But 1941 to 1982 is only 41 years. How about the other 20‐odd years?

Environmental noise emissions from on‐site diesel electric generators

The installation of on‐site diesel generators as an alternative to purchasing electric power from a central source may be accompanied by an adverse environmental noise impact. Noise vibration emissions from on‐site diesel engine generators need not become a source of community annoyance if regulatory agencies require and review noise impact analyses for new installations, and if adequate noise abatement devices are installed and maintained. A noisy installation may become a chronic source of community annoyance, since retrofitting noise controls to an existing installation, when feasible, can be extremely costly and may therefore not be implemented. This paper reports on a study which developed procedures for (1) calculating environmental noise and vibration emissions from on‐site diesel generators which consider variables such as proximity to nearest neighbor, local ambient sound levels, location of the facility, method of cooling and type, size and quality of equipment to be installed, and (2) estimatin...

Vibration‐Isolation Treatment of a Railroad Track Bed

A few years ago, a half‐mile section of railroad track was given a vibration‐isolation treatment under several new buildings in Boston. The treatment consisted of welding all rail joints, inserting molded rubber rail seats under the lower flange of the rail, and installing an extra‐deep ballast bed under the ties. Recently, a simple measurement was made of the earthborne vibration reduction provided by this treatment. A vibration pickup was mounted on a concrete wall inside the track, and the signal was tape recorded for passages of several short passenger trains. At one position, the vibration pickup was located beside the welded and isolated track. On the following day, the same passenger trains were recorded with the vibration pickup located beside conventional unwelded and unisolated track, approximately 200 yd from the first position. Train speed, train makeup, wheel loads, earth conditions, and the geometry of the measurement conditions were quite similar for both locations, so it is believed that t...

Noise‐Control Design for the Main Hall of the Canadian National Arts Center in Ottawa

The main auditorium of the new National Arts Center in Ottawa is bounded by several mechanical equipment rooms that house the air‐handling equipment for the auditorium and its stage area and for some of the other parts of the total complex. Noise‐control design includes: (1) control of fan noise through the ducts, (2) control of fan noise into the mechanical rooms themselves, (3) control of the escape of mechanical room noise into the auditorium and stage areas, (4) control of air movement noise in the ducts, and (5) control of damper and diffuser noise. Vibration control includes the vibration isolation of fans, pumps, ducts, and piping in various crucial locations. The exterior shell of the building has been designed to exclude city noise and to limit the intrusion of aircraft noise. A very brief summary is given of the noise criterion goals and the design objectives for achieving those goals.The main auditorium of the new National Arts Center in Ottawa is bounded by several mechanical equipment rooms that house the air‐handling equipment for the auditorium and its stage area and for some of the other parts of the total complex. Noise‐control design includes: (1) control of fan noise through the ducts, (2) control of fan noise into the mechanical rooms themselves, (3) control of the escape of mechanical room noise into the auditorium and stage areas, (4) control of air movement noise in the ducts, and (5) control of damper and diffuser noise. Vibration control includes the vibration isolation of fans, pumps, ducts, and piping in various crucial locations. The exterior shell of the building has been designed to exclude city noise and to limit the intrusion of aircraft noise. A very brief summary is given of the noise criterion goals and the design objectives for achieving those goals.

Subway‐Vibration Measurements at the New Lincoln Center Philharmonic Hall

The design of the new Philharmonic Hall at the Lincoln Center for the Performing Arts in New York has incorporated certain provisions for the reduction of earth‐borne and structure‐borne noise and vibration into the building from the nearby subway running beneath Broadway. Vibration levels due to subway passages were measured at several positions within the building following completion of the main structure. The vibration‐isolation treatments and the results of the vibration measurements are described.

Noise and Vibration Measurements of a Large Ventilating Fan for Various Degrees of Vibration Isolation

We were recently presented with the opportunity of making a series of noise and vibration measurements on a 25‐hp ventilating fan located above an occupied floor in an office building. The measurements were carried out during the process of trying to diagnose the cause of excessive noise levels in the office floor beneath the fan. Vibration levels at various parts of the fan base and noise levels in the office area below are presented for various degrees of isolation of the fan on its mounting.

Comparison of the Take‐Off Noise Characteristics of the Comet Jet Airliner and of Conventional Propeller‐Driven Airliners

This paper presents noise data obtained during recent tests of the prototype of the British Comet 4 airliner in take‐offs from the De Havilland plant at Hatfield, England. The data are analyzed in terms of noise levels, spectrum distribution, and noise duration and are compared with related data obtained from tests with several propeller‐driven airliners. Measurement positions were located at points under the take‐off path corresponding to residential areas near present‐day airports. This work was sponsored by the Port of New York Authority.

Noise Characteristics of Some Commercial Jet Aircraft during Ground Operations

Measurements have been made of the noise of two commercial jet aircraft, the French Caravelle and the British Comet, during ground runup and take‐off operations. Noise directivity measurements taken during the ground runup operations are presented as a function of engine power and number of operating engines. These results provide data on the noise of two commercial jet aircraft using engines with and without in‐flight suppressors. From both the take‐off noise data, measured to the side of the runway, and the static ground runup data, estimates are made of the average maximum noise levels that can be expected outside airport terminal buildings due to various operations of commercial jet aircraft.

Comparison of the Take‐Off Noise Characteristics of the Caravelle Jet Airliner and of Conventional Propeller‐Driven Airliners

This paper presents comparative noise data obtained during recent tests on the French Caravelle twin‐jet airliner and on large propeller‐driven airliners in measurements at Orly Airport in Paris and at New York International Airport at Idlewild. Data are analyzed in terms of noise levels, spectrum content, and noise duration for several take‐offs over measurement positions located at points corresponding to residential areas near present‐day airfields. [This work was sponsored by the Port of New York Authority.]