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2016-11-08
Technical Paper
2016-32-0049
Kuniyoshi Eto, Masaru Nozawa, Masato Nara, Buhei Kobayashi, Daiki Shibasaki, Ken Shirai
Abstract A new air-cooled SI two-stroke gasoline engine has been developed for an arborist-chainsaw. This engine has a displacement of 25 cm3 and generates about 1.1 kW and complies with the latest CARB and EPA exhaust regulations by optimizing scavenging flows and the use of a catalytic converter. Characteristics of lightweight, compact and high power-to-weight ratio are required for handheld chainsaws, especially for arborist chainsaws. As a matter of course, these characteristics are needed for engine itself in order to satisfy such market requirements for hand-held power equipment. To realize lightweight and compact design, the placement of catalytic converter is optimized for the engine and a two-piece crankshaft is adopted.
2016-11-08
Journal Article
2016-32-0034
Stephan Jandl, Hans-Juergen Schacht, Stephan Schmidt, Ute Dawin, Armin Kölmel, Stefan Leiber
Abstract Worldwide increasing energy consumption, decreasing energy resources and continuous restriction of emission legislation cause a rethinking in the development of internal combustion engines and fuels. Alternative renewable fuels, so called bio-fuels, have the potential to contribute to environmentally friendly propulsion systems. This study concentrates on the usage of alcohol fuels like ethanol, methanol and butanol in non-automotive high power engines, handheld power tools and garden equipment with the focus on mixture formation and cold start capability. Although bio-fuels have been investigated intensely for the use in automotive applications yet, the different propulsion systems and operation scenarios of nonautomotive applications raise the need for specific research. A zero dimensional vaporization model has been set up to calculate the connections between physical properties and mixture formation.
2016-10-25
Technical Paper
2016-36-0393
Thales Sardinha Garcia Souza, Márcio Henrique Pereira, Roberto Martins de Souza
Abstract The cost of any forged product for the automotive industry is highly influenced by the cost involved during the design and manufacturing of the forging tools. Ideally, these tools shall withstand a significant number of cycles, in order to divide their manufacturing cost in many parts as possible. There are several parameters that affect the wear behavior, and forging companies have different approaches to address the tribological issues. Moreover, a misunderstanding of these parameters may lead to an undesirable premature tool wear. This work analyses the effect of roughness on the wear of cold forming tools. The adopted tribosystem is the second stage of a horizontal press and consists of a punch of M2 hardened steel in relative movement against a working piece of SAE 10B22 normalized steel. Fifteen punches were manufactured with three roughness levels and their wear was measured after 50.000 and 100.000 forging cycles.
2016-09-27
Technical Paper
2016-01-2108
Marc Fette, Kim Schwake, Jens Wulfsberg, Frank Neuhaus, Manila Brandt
Abstract The rising demand for civil aircraft leads to the development of flexible and adaptive production systems in aviation industry. Due to economic efficiency, operational accuracy and high performance these manufacturing and assembly systems must be technologically robust and standardized. The current aircraft assembly and its jigs are characterized by a high complexity with poor changeability and low adaptability. In this context, the use of industrial robots and standardized jigs promise highly flexible and accurate complex assembly operations. This paper deals with the flexible and adaptable aircraft assembly based on industrial robots with special end-effectors for shaping operations. By the development and use of lightweight gripper system made of carbon fiber reinforced plastics the required scaling, robustness and stiffness of the whole assembly system can be realized.
2016-09-27
Technical Paper
2016-01-2110
Ilker Erdem, Peter Helgosson, Ashwin Gomes, Magnus Engstrom
Abstract The ability to adapt to rapidly evolving market demands continues to be the one of the key challenges in the automation of assembly processes in the aerospace industry. To meet this challenge, industry and academia have made efforts to automate flexible fixturing. LOCOMACHS (Low Cost Manufacturing and Assembly of Composite and Hybrid Structures) - a European Union funded project with 31 partners - aims to address various aspects of aero-structure assembly with a special attention directed to the development of a new build philosophy along with relevant enabling technologies. This paper aims to present the results on the developed wing box build philosophy and the integration of automated flexible tooling solutions into the assembly process. The developed solution constitutes the use of synchronized hexapods for the assembly of front spar to upper cover whereas another hexapod was developed to install a rib by using of a force feedback sensor.
2016-09-27
Technical Paper
2016-01-2107
Rainer Mueller, Matthias Vette, Matthias Scholer, Jan Ball
Abstract The global competition challenges aircraft manufactures in high wage countries. The assembly of large components is very difficult and distinguished by fixed position assembly. Many complex assembly processes such as aircraft assembly are manually done by highly skilled workers. The aircraft manufactures deal with a varying number of items, increasing number of product variants and strict product requirements. During the assembly process hundreds of clips, ties and stringers as well as thousands of rivets must be assembled. To remain competitive in global competition, companies in high wage countries like Germany must insure a continuously high productivity and quality level. To achieve a reduction of cycle times with a simultaneous increase in quality, supportive assistance systems for visual support, documentation and organization within the assembly are required. One example for visual assistance systems are laser projection systems.
2016-09-27
Technical Paper
2016-01-2109
Michael Morgan, Caroline McClory, Colm Higgins, Yan Jin, Adrian Murphy
Aerospace structures are typically joined to form larger assemblies using screw lock or swage lock fasteners or rivets. Countersunk fasteners are used widely in the aerospace industry on flying surfaces to reduce excrescence drag and increase aircraft performance. These fasteners are typically installed to a nominal countersink value which leaves them flush to the surface before being locked into position. The Northern Ireland Technology Centre (NITC) at Queen’s University Belfast has developed and demonstrated two processes which enable high tolerance flush fastening of countersunk fasteners: The ‘Flush Install’ process produces countersunk holes based on the specific geometry of each individual fastener; The ‘Fettle Flush’ process accurately machines fasteners to match the surrounding surface. Flushness values well within the allowable tolerances have been demonstrated for both Flush Install and Fettle Flush processes.
2016-09-27
Technical Paper
2016-01-2106
Dan R.W. Vaughan, Otto J. Bakker, David Branson, Svetan Ratchev
Abstract Aircraft manufacturers desire to increase production to keep up with anticipated demand. To achieve this, the aerospace industry requires a significant increase in the manufacturing and assembly performance to reach required output levels. This work therefore introduces the Variation Aware Assembly (VAA) concept and identifies its suitability for implementation into aircraft wing assembly processes. The VAA system concept focuses on achieving assemblies towards the nominal dimensions, as opposed to traditional tooling methods that aim to achieve assemblies anywhere within the tolerance band. It enables control of the variation found in Key Characteristics (KC) that will allow for an increase in the assembly quality and product performance. The concept consists of utilizing metrology data from sources both before and during the assembly process, to precisely position parts using motion controllers.
2016-09-27
Technical Paper
2016-01-2096
Simon Schnieders, Dirk Eickhorst
Abstract Drilling of high-strength titan material and composites in combination creates complex challenges in order to achieve required productivity and quality. Long spiral chips are characteristically for the titan drilling process, which leads to e.g. chip accumulation, high thermomechanical load, surface damages and excessive tool wear. The basic approach is the substitution of today’s peck drilling as current solution to this problem and the implementation of a vibration assisted drilling, so called micro-peck-drilling-process, to generate a kinematic chip breakage in a significant more efficient way. To meet perfectly the requirements regarding rates, quality and automation level, Broetje-Automation as system integrator has investigated and developed the implementation of different alternative high-performance systems and methods to approach the optimal oscillation movement of the tool.
2016-09-27
Technical Paper
2016-01-2127
Sylvain Guerin, Sylvain da Costa
Abstract The recent contribution rise in 3D printing is rapidly changing the whole industry. In aeronautics, it has 2 major domains of growth: Aircraft parts Tooling and portable tools Aircraft parts in metallic 3D printing have been highly publicized in the media, although they represent only a tiny share of the aircraft cell in the short term. On the other hand, metallic (and non-metallic) 3D printing in tooling and tools can bring immediate advantages compared to traditional methods. The advantages: Design made directly for the final function Optimized for strength vs weight Weight reduction Reduction in number of parts Short cycle time from design to use Low cost for customization The drawbacks Limited in size We have already applied this new manufacturing technique to obtain real breakthroughs in portable tools.
2016-09-27
Journal Article
2016-01-2082
Ralf Schomaker, Björn Knickrehm, Jürgen Langediers
Abstract In the frame of incremental product improvement, AIRBUS has developed and implemented a new innovative rapid decompression / pressure relieve concept for the cargo compartment area. The core change lays with detaching the complete cargo lining panels from the substructure in case of a rapid decompression in the cargo area instead of using dedicated blow in panels. In that way, pressure equilibrium can be achieved by air flow through the opened areas around the cargo lining panels rather than through specific blow out / blow in venting areas. The key for this is a self-detaching fastener AIRBUS has developed in an outstanding cooperation with ARCONIC Fastening Systems & Rings (former Alcoa Fastening Systems & Rings) in Kelkheim, Germany. These fasteners are installed to keep the cargo lining panels in place and tight against smoke in case of fire which is one of the main purposes for their use.
2016-09-27
Technical Paper
2016-01-2077
Fatih Burak Sahin, Hans-Juergen Borchers, Cagatay Ucar
Abstract CFRP has been widely used in aerospace industries because of its high strength-to-weight ratio. However, drilling CFRP laminates is difficult due to the highly abrasive nature of the carbon fibers and low thermal conductivity of CFRP. Therefore for the manufacturers it is a challenge to drill CFRP materials without causing any delamination within the high quality requirements while also considering the costs of the process. This paper will discuss the process of drilling CFRP-Al stack ups within tight tolerances using a seven axis drilling robot. All components required for drilling are integrated in the drill end-effector. The pressure foot is extended in order to clamp the work piece, and then holes are drilled. The drilling process has four steps: moving to the fast approach level, controlled drill feed, countersink depth reach and drill retract. The cutter diameter range chosen for this paper is Ø 4.0 mm and Ø 7.9 mm.
2015-11-17
Technical Paper
2015-32-0843
Marek Lajda, Sebastian Hook, Nikolai Reimgen
During the start-up phase of machines it can happen that tools are inadvertently rotating, which is caused by the half-throttle setting. Due to the starting throttle locking mechanism, the engine's rotational speed is above the engagement speed of the tool (for example the chain of a chain saw). This article describes the software algorithms developed by PRUFREX that are able to prevent rotation of the tool upon machine start at idle. The patented software solution is able to differentiate between start behavior with and without a starting throttle locking mechanism based on the machine's speed and time information and, as a result, can identify or estimate the position of the throttle valve. The effect of the algorithms is the switch-over between different ignition curves that are stored in the microcontroller-operated ignition modules. This includes a provision in the start ignition curve that prevents the tool from rotating.
2015-10-01
Journal Article
2015-01-9019
Jean-Baptiste Gallo, Robert L. Russell, Kent Johnson, Thomas Durbin
Abstract With funding from the California Energy Commission, the California Hybrid, Efficient and Advanced Truck Research Center, contracted with the University of California, Riverside's College of Engineering to evaluate the performance of a Class 5 battery electric urban delivery vehicle over two standardized driving cycles and a steady state range test on a chassis dynamometer. The test vehicle, a Smith Electric Newton Step Van, was equipped with a proprietary data acquisition system which was set to record a wide variety of vehicle parameters at a 1 Hz sampling period. In addition, the chassis dynamometer was set to measure and record additional parameters. Lastly, a portable J1772 EVSE recorded both grid energy and power at 15-minute intervals. This project provides a controlled test evaluation of the Smith Electric Newton Step Van.
2014-11-11
Technical Paper
2014-32-0036
Jan Czerwinski, Markus Kurzwart, Andreas Mayer, Pierre Comte
Abstract The progressing exhaust gas legislation for on- and off-road vehicles includes gradually the nanoparticle count limits. The invisible nanoparticles from different emission sources penetrate like a gas into the living organisms and may cause several health hazards. The present paper shows some results of a modern chain saw with & without oxidation catalyst, with Alkylate fuel and with different lube oils. The measurements focused specially on particulate emissions. Particulates were analysed by means of gravimetry (PM) and granulometry SMPS (PN). In this way the reduction potentials with application of the best materials (fuel, lube oil, ox-cat.) were indicated. It has been shown that the particle mass (PM) and the particle numbers (PN), which both consisting almost exclusively of unburned lube-oil, can attain quite high values, but can be influenced by the lube oil quality and can be considerably reduced with an oxidation catalyst.
2014-11-11
Technical Paper
2014-32-0111
Brian Mason, Keith Lawes
Abstract For handheld power tools, a four-stroke engine allows compliance with exhaust emissions regulations although four-stroke engines available tend to have unfavorable power to weight. The requirement for a low cost diecast block compromises valve sizes and port flow. While dynamic valve train limitations restrict maximum engine speeds. The use of a rotary valve as opposed to poppet valves avoids these issues and results in an engine with competitive performance. The engine block can be diecast and the engine can operate up to 14,000 rpm without valve related issues. This paper describes the evolution of a rotary valve concept and its application to two 35cc handheld development engines. The HRCV35 is based on a belt driven rotary valve horizontally mounted parallel to the crankshaft axis. The VRCV35 is based on a gear driven rotary valve vertically mounted on the cylinder axis. In both configurations, the rotary valve exposes inlet and exhaust ports providing unrestricted flow.
2014-11-11
Technical Paper
2014-32-0115
Mikael Bergman, Magnus Bergwall, Thomas Elm, Sascha Louring, Lars Nielsen
Abstract Present two stroke engines used for hand held power tools must confirm to prevailing emission legislation. A fact is that today the engines have to be run at leaner air fuel setting resulting in less amount of lubrication oil passing through the engine. This lean mixture combined with high mixture trapping efficiency also affects the combustion, raising the overall working temperature of the engine. So to gain more robustness out of these air-cooled power heads one viable route is to use different coatings to take control of tribology and heat management within the two stroke power head. In this paper a first discussion and description of the different coatings and their merits to the air cooled two stroke engine is conducted. Furthermore engine data for the test engine, in this case a 70cc professional chainsaw are presented. The outcome of engine dyno testing of the different coatings are presented and analyzed for further discussion.
2014-11-11
Journal Article
2014-32-0009
Alexander Trattner, Helmut Grassberger, Oliver Schoegl, Stephan Schmidt, Roland Kirchberger, Helmut Eichlseder, Armin Kölmel, Stephan Meyer, Tim Gegg
Abstract One of the most significant current discussions worldwide is the anthropogenic climate change accompanying fossil fuel consumption. Sustainable development in all fields of combustion engines is required with the principal objective to enhance efficiency. This certainly concerns the field of hand-held power tools as well. Today, two-stroke SI engines equipped with a carburetor are the most widely used propulsion technology in hand-held power tools like chain saws and grass trimmers. To date, research tended to focus on two-stroke engines with rich mixture setting. In this paper the advantages and challenges of leaner and/or lean operation are discussed. Experimental investigations regarding the influence of equivalence ratio on emissions, fuel consumption and power have been performed. Accompanying 3D-CFD simulations support the experiments in order to gain insight into these complex processes. The investigations concentrate on two different mixture formation processes, i.e.
2013-09-17
Technical Paper
2013-01-2227
Shuhei Segawa, Junich Tamura, Satoshi Suzuki, Hisao Oka, Kiichi Meguro, Yoshiji Satou
In the expansion of composite material application, it is one of the most important subjects in assembly of aircraft structure how drilling of composite/metal stack should be processed in an efficient way. This paper will show the result of development of a drill bit for CFRP/Aluminum-alloy stack by Kawasaki Heavy Industries (KHI) and Sumitomo Electric Hardmetal (SEH). In order to improve workability and economic performance, the drill bit which enables drilling CFRP/Al-alloy stack: at 1 shot; from both directions; without air blow and coolant (just usual vacuuming); was required. A best mix drill bit which has smooth multi angles edge and pointed finishing edge was produced as a result of some trials. Developed drill bit achieved required performance and contributed to large cost reduction, labor hour saving, production speed increase and work environment improvement.
2009-11-10
Technical Paper
2009-01-3270
Cris Cobzaru
New concepts in research and development with Cherry Aerospace are leading to major advancements in portable riveter functionality. A hand powered riveter using some of these concepts is light, compact, ergonomically fitted, and capable to reach very high installation loads with low hand effort and reduced actuations to installation. It is capable to install of a wide variety of blind fasteners used in aircraft maintenance and repair. This paper outlines the design tools and concepts used to develop this unit as well as the tested performance characteristics. The technologies incorporated into this unit are a preview of the capabilities of the next generation of smaller, stronger, composite friendly and ergonomic riveters.
2009-11-10
Technical Paper
2009-01-3269
Rodrigo Pinheiro, Charles Dibley, Jay Olkowski, Richard Lantow, Luke Haylock
The installation of aerospace fasteners with pneumatic or cordless tools generally requires specialized systems which are dedicated to the fastener hex size and torque, often requiring laborious disassembly for a configuration change. This paper presents a quick change system that can be used together with a large variety of tooling configurations and provides instant socket exchange without requiring wrenching or disassembly. A comparison with traditional socket system is made, highlighting the characteristics and benefits of this new technology in terms of ergonomics, productivity and cost.
2009-11-10
Technical Paper
2009-01-3268
Rodrigo Pinheiro, Edgar Frias, Richard Lantow, Jay Olkowski, Luke Haylock
Following the trend in automotive manufacturing, electric cordless tooling platforms are gradually being adopted for aerospace assembly tool systems. This paper introduces a new portable aerospace fastener assembly tool system based on the cordless electric technology platform. These systems are significantly more accurate than traditional pneumatic–based assembly tool systems and offer a range of process monitoring options. Cordless assembly tool systems make the assembly process easier, faster, safer and more accurate. These systems have the ability to provide traceability with time & date stamp for each installed fastener and provide wireless communication to enable process monitoring in real time. A comparison with traditional aerospace tool systems is made, in terms of historical evolution and working performance. Lessons learned from automotive applications are brought to aerospace industry. Key benefits include better ergonomics, improved accessibility, productivity and cost.
2009-10-06
Technical Paper
2009-36-0379
M.Eng Carlos Alberto Kern Thomas, Vilson João Batista, Tiago Becker, Roberto Valentino Boeing, Kleber Eduardo Bianchi
This paper describes a project developed of a electronics instrumentation to obtain the needed data to compare the performance of differents agricultural tractors. A first system allows the measurement and recording of variables used in laboratory tests. The laboratory tests are made according to a technical standard used by agricultural tractors manufacturers. In this article, it will be presented the specific fuel consumption results for different characteristics and manufacturers tractors. In this case, this agricultural equipment were subjected to different working conditions in dynamometer tests. The performance of these vehicles also can be evaluated during a variety of agriculture business activities, such as transportation, preparation of soil, planting and harvesting. The second measurement system developed is an on board interface which allows registering the values of main physical parameters, needed to evaluate the performance of the tractor in field operation.
2009-07-12
Technical Paper
2009-01-2397
M. Saccoccio, A. Gaboriaud, R. Pérez, B. Faure, K. Gasc, Y. Michel, F. Marlats, E. Courau, S. Mary, V. Cipolla, L. Picot, D. Faye, J.M. Desmarres, F. Bourcier, G. Pérez, D. Buso, O. Gilard, G. Quadri, H. Combes, V. Costes, T. Jamin, T. Battault, JL. Lortal, D. Gervaud, S. Maurice, A. Cros, J. Thocaven, H. Seran, Y. Parot, G. Orttner, L. Parés, H. Valentin, P. Couderc, J. Platzer, M. Dupieux, T. Gharsa, D. Kouach, B. Dubois, N. Striebig, M. Bouyé, P. Ca ïs, B. Quertier, M. Berthé, R. Wiens, B. Barraclough, J. Bernardin, S. Bender, S. Clegg, R. Stiglich, D. Landis, T. Hale, D. Blaney, C. Hayes, C. Lindensmith, T. Elliott, E. Millar, E. Kan, E. Morse
ChemCam is one of the 10 instrument suites on the Mars Science Laboratory, a martian rover being built by Jet Propulsion Laboratory, for the next NASA mission to Mars (MSL 2009). ChemCam is an instrument package consisting of two remote sensing instruments: a Laser-Induced Breakdown Spectrometer (LIBS) and a Remote Micro-Imager (RMI). LIBS provides elemental compositions of rocks and soils, while the RMI places the LIBS analyses in their geomorphologic context. Both instruments rely on an autofocus capability to precisely focus on the chosen target, located at distances from the rover comprised between 1 and 9 m for LIBS, and 2 m and infinity for RMI. ChemCam will help determine which samples, within the vicinity of the MSL rover, are of sufficient interest to use the contact and in-situ instruments for further characterization.
2009-07-12
Journal Article
2009-01-2588
Vincenzo Cascioli, Roberto Battiston, Marco Gottero, Enrico Sacchi
In several industrial fields, the integration of functions is a key technology to enhance the efficiency of components in terms of performance to mass/volume/cost ratio. Concerning the space industry, in the last few years the trend in spacecraft design has been towards smaller, light-weight and higher performance satellites with sophisticated payloads and instrumentation. Increasing power density figures are the common feature of such systems, constituting a challenging task for the Thermal Control System. The traditional mechanical and thermal design concepts are evidencing their limits with reference to such an emerging scenario.
2009-07-12
Journal Article
2009-01-2432
Ben D. Gardner, Phillip M. Erwin, Wai Tak Lee, Amber M. Tissandier, Souzan M. Thoresen
The Major Constituent Analyzer (MCA) is a mass spectrometer based system that measures the major components of the International Space Station (ISS) atmosphere, including water. The measurement of water vapor has been difficult due to adsorption on various surfaces in the sample path, and has thus far been discounted in MCA atmosphere monitoring. This paper summarizes the results in identifying the primary source of the problem, the modeling being used to further elucidate the water surface adsorption/desorption process, and the proposed means available to provide a stable calibration and accurate measure of the water abundance.
2009-07-12
Technical Paper
2009-01-2528
Roman V. Kruzelecky, Brian Wong, Jing Zou, Emile Haddad, Wes Jamroz, Edward Cloutis, Nadeem Ghafoor, Sean Jessen, Gita Ravindran
The feasibility of extended human presence on the Moon and Mars depends critically on in-situ resource utilization (ISRU) to mitigate the high interplanetary transportation costs. Key resource requirements include water, oxygen, fuel and a variety of building materials. This paper discusses the robotic instrumentation associated with the LORE (Lunar Origins and Resource Exploration) miniature payload proposed for JAXA's Selene-2, and the potential follow-on CSA INUKSHUK landed-Mars mission. LORE would for the first time systematically explore the lunar surface and subsurface ice distribution, dust, mineralogy and resources using combined UV/VIS/MIR reflectance spectroscopy. The spectral differences between ilmenite and other lunar minerals in the ultraviolet region will be exploited for mapping ilmenite distribution and abundances on the lunar surface and subsurface.
2009-07-12
Technical Paper
2009-01-2543
A. V. Shevade, M. A. Ryan, M. L. Homer, A. K. Kisor, K. S. Manatt, L. M. Lara
Simultaneous measurements were made for particle releases and off-gassing products produced by heating electrical wires. The wire samples in these experiments were heated to selected temperatures in a heating chamber and responses to vapor releases were recorded by the JPL Electronic Nose (ENose) and an Industrial Scientific ITX gas-monitor; particles released were detected by a TSI P-Trak particle counter. The temperature range considered for the experiment is room temperature (24−26°C) to 500 °C. The results were analyzed by overlapping responses from the ENose, ITX gas sensors and P-Trak, to understand the events (particle release/off-gassing) and sequence of events as a function of temperature and to determine qualitatively whether ENose may be used to detect pre-combustion event markers.
2009-07-12
Technical Paper
2009-01-2544
Craig Peterson, M. A. Ryan
In recent years, several different technologies have been considered for use in environmental monitoring and control of spacecraft habitat. These technologies have included monitoring for both water and air. This paper will discuss construction of a trade space for environmental monitoring technologies. Previous trade space metric approaches are reviewed and a new approach is outlined. Trade space considerations include the usual mass, power and volume, along with sensitivity, accuracy, speed of response, frequency of measurement and ease of use. These considerations will be discussed in the context of Constellation program vehicles. In addition to a new approach for trade space construction, this paper will briefly discuss the application of this trade space to a selection of technologies taken from NASA programs, ESA programs, COTS technologies and DoD programs.
2009-05-19
Technical Paper
2009-01-2156
Robert Hickling
Sound intensity is the time average of sound-power flow per unit area in watts/m2. It is generally measured using sound pressure at two closely-spaced microphones. It is commonly believed that it is not possible to measure sound intensity in a reverberation room because multiple reflections in the room create a diffuse pressure field which makes such measurements inaccurate. However there has to be a net flow of sound power in the room from speakers (or other sources) which then passes out through the walls, ceiling and floor. Hence net sound power flow (sound intensity) should be measurable. In a previous paper [1]* it was shown that it is possible to measure the sound power of a reference source accurately in three different reverberation rooms using sound-intensity measurement. Accurate measurements were also made in other work spaces. In this paper the sound-intensity method is compared with the method used by the manufacturer to calibrate a reference source.
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