Sample records for mufflers

  1. Numerical simulation design of nuclear safety related expansion muffler

    International Nuclear Information System (INIS)

    Huang Bingchen; Shen Wei; Yang Tieming; Luo Jianping; Jing Feng


    According to the working conditions and technical requirements for pipe discharge muffler in passive nuclear power plant, the numerical simulation was used in analyzing sound transmission loss and fluid pressure loss of multi-section expansion muffler by finite element analysis (FEA) software ANSYS. The effect of different muffler structural parameters on sound transmission loss, passing frequency and pressure loss was also analyzed. Based on the analysis results, a reasonable combination of the muffler structural parameters was determined, and a pipe discharge muffler with good performance was obtained. (authors)

  2. A Muffler Design for Tank Cannon Acceptance Testing (United States)


    designed a muffler to reduce the noise associated with proofing. This muffler is ;maller and lighter than the mufi ±rs tested by CSTA. Figure 1 shows...1 Old Dominion University Mathematics Department ATITN: Dr. Charlie Cooke Norfolk, VA 23508 Aberdeen Proving Ground 2 Dir, USAMSAA ATIN: AMXSY-D, Mr


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    Sujit Kumar Jha


    Full Text Available The muffler is the main part of the Automobile Exhaust System, consisting of fibrous and porous materials to absorb noise and vibrations. The exhaust gas mass coming from the engine can produce resonance, which may be the source of fatigue failure in the exhaust pipe due to the presence of continuous resonance. The modes on the muffler should be located away from the engine’s operating frequencies in order to minimise the resonance. The objective of this paper is to determine the frequencies that appear at the modes, which have the more adverse effect during the operation of the automobile. An impact test has been conducted by applying the force using a hard head hammer, and data generated have been used for plotting a graph of the transfer functions using MATLAB. Six points have been selected, namely 1, 2, 3, 4, 7, and 11 on the muffler for the impact test. The collected data from theses six points have been analysed for the addition of damping. Results suggests that increasing the mass increases the damping and lowers the modes of the transfer function. Further research will identify higher strength materials that can withstand the higher gas temperatures as well as the corrosion and erosion by the gas emitted from the engine. muffler, noise, vibration,modal analysis,


    Directory of Open Access Journals (Sweden)

    Sujit Kumar Jha


    Full Text Available The muffler is the main part of the Automobile Exhaust System, consisting of fibrous and porous materials to absorb noise and vibrations. The exhaust gas mass coming from the engine can produce resonance, which may be the source of fatigue failure in the exhaust pipe due to the presence of continuous resonance. The modes on the muffler should be located away from the engine’s operating frequencies in order to minimise the resonance. The objective of this paper is to determine the frequencies that appear at the modes, which have the more adverse effect during the operation of the automobile. An impact test has been conducted by applying the force using a hard head hammer, and data generated have been used for plotting a graph of the transfer functions using MATLAB. Six points have been selected, namely 1, 2, 3, 4, 7, and 11 on the muffler for the impact test. The collected data from theses six points have been analysed for the addition of damping. Results suggests that increasing the mass increases the damping and lowers the modes of the transfer function. Further research will identify higher strength materials that can withstand the higher gas temperatures as well as the corrosion and erosion by the gas emitted from the engine.

  5. Acoustic performance of industrial mufflers with CAE modeling and simulation

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    Jeon Soohong


    Full Text Available This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/ SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive elements, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.

  6. Acoustic performance of industrial mufflers with CAE modeling and simulation

    Directory of Open Access Journals (Sweden)

    Soohong Jeon


    Full Text Available This paper investigates the noise transmission performance of industrial mufflers widely used in ships based on the CAE modeling and simulation. Since the industrial mufflers have very complicated internal structures, the conventional Transfer Matrix Method (TMM is of limited use. The CAE modeling and simulation is therefore required to incorporate commercial softwares: CATIA for geometry modeling, MSC/PATRAN for FE meshing and LMS/SYSNOISE for analysis. Main sources of difficulties in this study are led by complicated arrangement of reactive ele- ments, perforated walls and absorption materials. The reactive elements and absorbent materials are modeled by applying boundary conditions given by impedance. The perforated walls are modeled by applying the transfer impedance on the duplicated node mesh. The CAE approach presented in this paper is verified by comparing with the theoretical solution of a concentric-tube resonator and is applied for industrial mufflers.

  7. Investigation of baffle configuration effect on the performance of exhaust mufflers

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    Ahmed Elsayed


    Full Text Available Using baffles in exhaust mufflers is known to improve their transmission loss. The baffle cut ratio should affect the muffler performance analogous to a shell-and-tube heat exchanger. To the authors’ knowledge, there is no previous assessment reported in literature of the effects that the baffle cut ratio configuration has on acoustic response and back pressure. This investigation presents a parametric study on the effect of baffle configuration on transmission loss and pressure drop predicted. The effect of (i the baffle cut ratio and baffle spacing, (ii the number of baffle holes, and (iii the hole distribution for their effect on transmission loss was investigated. Results show that decreasing the baffle cut ratio tends to increase the transmission loss at intermediate frequencies by up to 45%. Decreasing the spacing between muffler plates was shown to enhance the muffler transmission loss by 40%. To assess the baffle effect on flow, the OpenFoam CFD libraries were utilized using the thermal baffle approach model. Baffles were found to cause sudden drop in fluid temperature in axial flow direction. The outlet exhaust gases temperature was found to decrease by 15% as the baffle cut ratio changed from 75% to 25%.

  8. False-positive I-131 scan by contaminated muffler in a patient with thyroid carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Han Kyung; Kim, Min Woo; Jeong, Hwan Jeong; Sohn, Myung Hee [Chonbuk National University Hospital, Chonju (Korea, Republic of)


    A 39-year-old female patient who had undergone a total thyroidectomy for a papillary thyroid carcinoma underwent a whole body scan with I-131. The I-131 scan was performed 72 hours after administering 185 MBq (5 mGi) of an I-131 solution. The anterior image of head, neck, and upper chest showed multiple areas of increased uptake in the mediastinal area considering of functional metastasis. However, radioactivity was not evident in the image taken after removing her clothes and muffler. The image obtained after placing the muffler on the pallet showed that the radioactivity was still present. It is well known that artifacts on an I-131 scan can be produced by styling hair sputum, drooling during sleep, chewing gum, and paper or a cloth handkerchief that is contaminated with the radioactive iodine from either perspiration or saliva. This activity might be mistaken for a functional metastasis. Therefore, it is essential that an image be obtained after removing the patient's clothes. In this study, artifacts due to a contaminated muffler on the I-131 scan were found. These mimicked a functional metastasis of the mediastinal area in a patient with a papillary thyroid carcinoma.

  9. Sound Attenuation in Elliptic Mufflers Using a Regular Perturbation Method


    Banerjee, Subhabrata; Jacobi, Anthony M.


    The study of sound attenuation in an elliptical chamber involves the solution of the Helmholtz equation in elliptic coordinate systems. The Eigen solutions for such problems involve the Mathieu and the modified Mathieu functions. The computation of such functions poses considerable challenge. An alternative method to solve such problems had been proposed in this paper. The elliptical cross-section of the muffler has been treated as a perturbed circle, enabling the use of a regular perturbatio...

  10. A result on the acoustic characteristics of the Mixture of Counter-phase Counteract and Split-gas Rushing muffler

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    Shao Ying-li


    Full Text Available The exhaust noise, which falls into low-frequency noise, is the dominant noise source of a diesel engines and tractors. The traditional exhaust silencers, which are normally constructed by combination of expansion chamber, and perforated pipe or perforated board, are with high exhaust resistance, but poor noise reduction especially for the low-frequency band noise. For this reason, a new theory of exhaust muffler of diesel engine based on counter-phase counteracts has been proposed. The mathematical model and the corresponding experimental validation for the new exhaust muffler based on this theory were performed.

  11. Reduction of external noise of mobile energy facilities by using active noise control system in muffler (United States)

    Polivaev, O. I.; Kuznetsov, A. N.; Larionov, A. N.; Beliansky, R. G.


    The paper describes a method for the reducing emission of low-frequency noise of modern automotive vehicles into the environment. The importance of reducing the external noise of modern mobile energy facilities made in Russia is substantiated. Standard methods for controlling external noise in technology are of low efficiency when low-frequency sound waves are reduced. In this case, it is in the low-frequency zone of the sound range that the main power of the noise emitted by the machinery lies. The most effective way to reduce such sound waves is to use active noise control systems. A design of a muffler using a similar system is presented. This muffler allowed one to reduce the emission of increased noise levels into the environment by 7-11 dB and to increase acoustic comfort at the operator's workplace by 3-5 dB.


    This report reflects verification testing of a catalytic muffler for diesel trucks. Produced by Donaldson Corp., it was tested on low sulfur and ultra low sulfur fuel, and shown to have reduced emissions.


    This report is on an environmental verification of the emissions characteristics of a Donaldson Corp. catalytic muffler and catalyic crankcase emissions control. It was found the systems reduced emissions.


    This report is on testing of a Donaldson Corp. catalytic muffler and closed crankcase filtration system for diesel trucks. It verified the emissions for these systems using low sufur and ultra low sulfur fuel.

  15. Simple rules for design of exhaust mufflers and a comparison with four-pole and FEM calculations

    DEFF Research Database (Denmark)

    Jensen, Morten Skaarup; Ødegaard, John


    For good muffler design it is advisable to use an advanced computational method such as four-pole theory or FEM or BEM. To get a starting points for these methods and to suggest adjustments to the geometry and materials it is useful to have some simple rules of thumb. This paper presents a number...... of such "rules", and illustrates their reliability and limitations by comparing with results using some of the advanced computational methods. At the same time, this investigation also gives a comparison between four-pole theory and BEM....

  16. Development of Energy Efficiency Design Map based on acoustic resonance frequency of suction muffler in compressor

    International Nuclear Information System (INIS)

    Oh, Seungjae; Wang, Semyung; Cho, Sungman


    Highlights: • Development of Energy Efficiency Design Map. • Experimental validation of Energy Efficiency Design Map. • Suggestion regarding the Acoustically Supercharged Energy Efficiency. • Sensitivity analysis of the Energy Efficiency Ratio with respect to acoustic pressure. • Suggestion regarding the hybrid coupling method for acoustic analysis in compressor. - Abstract: The volumetric efficiency of the Internal Combustion (IC) engine and compressor can be increased by properly adjusting the acoustic resonance frequency of the suction muffler or the suction valve timing without any additional equipment or power source. This effect is known as acoustic supercharging. However, the energy efficiency has become more important than the volumetric efficiency because of the energy shortage issue and factors influencing consumers’ purchasing decisions. Therefore, methods for increasing the energy efficiency using the acoustic effect in the suction part of IC engine and compressor should be considered. In this study, a systematic method for improving the energy efficiency using the acoustic effect in the suction part of the compressor used in refrigerators and air conditioners was developed for the first time. This effect is named as the Acoustically Supercharged Energy Efficiency (ASEE). For the ASEE, first, a hybrid coupling method was suggested for the acoustical analysis in the suction part of the compressor. Next, an Energy Efficiency Design Map (EEDM) was proposed. This can serve as a design guide for suction mufflers in terms of the energy efficiency. Finally, sensitivity analyses of the Energy Efficiency Ratio (EER) and total massflow rate with respect to the acoustic pressure were conducted to identify the relationship between the acoustic pressure and the suction valve motion. This provides the physical background for the EEDM

  17. Action des pots catalytiques sur les polluants non réglementés How Catalytic Mufflers Act on Unregulated Pollutants

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    Degobert P.


    Full Text Available L'installation de pots catalytiques sur les véhicules, envisagée essentiellement pour réduire le niveau des polluants actuellement réglementés (oxyde de carbone, hydrocarbures imbrûlés, oxydes d'azote, aura-t-elle des effets bénéfiques ou néfastes sur les polluants non réglementés ? Pour éclaircir cette question, cette étude compare sur des véhicules les plus comparables possibles du point de vue conception et équipements, les émissions des voitures non dépolluées et celles de voitures dépolluées , c'est-à-dire équipées de pots catalytiques d'oxydation, de pots catalytiques multifonctionnels ou de systèmes de combustion en mélange pauvre. Les polluants non réglementés pris en considération sont les aldéhydes, les sulfates, l'anhydride sulfureux, l'hydrogène sulfuré, l'oxysulfure de carbone, le cyanogène, l'acide cyanhydrique, l'acide nitrique, les aromatiques légers, les hydrocarbures aromatiques polycycliques, ces derniers en liaison avec leurs propriétés mutagènes. Le catalyseur a été considéré dans différents états : neuf, vieilli, empoisonné : l'influence des déréglages des systèmes de contrôle (avance, sonde à oxygène, allumage, etc. a été prise en compte. Il apparaît que la présence de catalyseur fonctionnant dans des conditions normales se révèle en général bénéfique sur la majorité des polluants ou tout au moins indifférente sur certains polluants. En outre les déréglages éventuels n'entraîneraient pas de concentrations alarmantes de ces polluants non réglementés. Will the equipping of vehicles with catalytic mufflers, planned mainly to reduce the level of currently regulated pollutants (carbon monoxide, unburned hydrocarbons , nitrogen oxides, have a beneficial or harmful effect on unregulated pollutants? To elucidate this question this article considers the vehicles that are the most comparable possible from the standpoint of design and equipment to compare emissions

  18. A Trigger or a Muffler? - Examining the Dynamics of Crosscutting Exposure and Political Expression in Online Social Media

    Directory of Open Access Journals (Sweden)

    Soo Young Bae


    Full Text Available This study explores the potential of online social media to serve as a sphere for political discourse and investigates the extent to which everyday uses of online social networking sites can expose citizens to politically diverse viewpoints.  In addition, this study asks whether such crosscutting exposure in online social networks will act as a trigger or a muffler for political expression – that is, whether exposure political difference will stimulate or discourage political discussions.  With analyses of a sample of online social networking site users in the context of the 2012 presidential election in South Korea, this study explicates the link between crosscutting exposure and citizens’ political expressions in social media.  Results reveal that contrary to the predictions in previous literature, exposure to politically incongruent viewpoints in online social networking sites does not seem to undermine users’ expressive behaviors but instead positively contribute to political expression.  In addition, this study shows the significant role of citizens’ perceptions of candidate support in their own networks, and illustrates that the dynamics of political expression differ significantly depending on the users’ age.

  19. Untitled

    Indian Academy of Sciences (India)

    Introduction. The majority of the commercial mufflers used on internal combustion engines contain one or more perforated tubes. These may interact with the surrounding annular cavity as in a Helmholtz resonator, or may conduct the gases as in plug mufflers and three-duct cross-flow or reverse-flow mufflers. Unfortunately,.

  20. Theoretical and Experimental Aspects of Acoustic Modelling of Engine Exhaust Systems with Applications to a Vacuum Pump (United States)

    Sridhara, Basavapatna Sitaramaiah

    In an internal combustion engine, the engine is the noise source and the exhaust pipe is the main transmitter of noise. Mufflers are often used to reduce engine noise level in the exhaust pipe. To optimize a muffler design, a series of experiments could be conducted using various mufflers installed in the exhaust pipe. For each configuration, the radiated sound pressure could be measured. However, this is not a very efficient method. A second approach would be to develop a scheme involving only a few measurements which can predict the radiated sound pressure at a specified distance from the open end of the exhaust pipe. In this work, the engine exhaust system was modelled as a lumped source-muffler-termination system. An expression for the predicted sound pressure level was derived in terms of the source and termination impedances, and the muffler geometry. The pressure source and monopole radiation models were used for the source and the open end of the exhaust pipe. The four pole parameters were used to relate the acoustic properties at two different cross sections of the muffler and the pipe. The developed formulation was verified through a series of experiments. Two loudspeakers and a reciprocating type vacuum pump were used as sound sources during the tests. The source impedance was measured using the direct, two-load and four-load methods. A simple expansion chamber and a side-branch resonator were used as mufflers. Sound pressure level measurements for the prediction scheme were made for several source-muffler and source-straight pipe combinations. The predicted and measured sound pressure levels were compared for all cases considered. In all cases, correlation of the experimental results and those predicted by the developed expressions was good. Predicted and measured values of the insertion loss of the mufflers were compared. The agreement between the two was good. Also, an error analysis of the four-load method was done.

  1. Comportement des pots catalytiques en présence de carburants oxygénés Behavior of Catalytic Mufflers in the Presence of Oxygenated Fuels

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    Degobert P.


    Full Text Available A partir d'un examen critique de la bibliographie disponible, et après un rappel des répercussions sur les émissions de la présence d'alcools dans les carburants, sont successivement examinées les performances d'épurateurs catalytiques multifonctionnels ou d'oxydation appliqués à des véhicules alimentés avec des carburants dont les teneurs en produits oxygénés varient entre 10 et 100 %. Les performances des catalyseurs s'écartent peu de celles constatées dans le cas de l'essence. Elles restent très bonnes vis-à-vis des polluants non réglementés. Par ailleurs, le pot catalytique n'engendre pas, dans ses conditions normales de fonctionnement, de polluants supplémentaires caractéristiques des combustibles oxygènes utilisés. Based on a critical examination of the literature available and after a review of the effects of the presence of alcools in fuels on emissions, this article successively examines the performances of multifunctional or oxidation catalytic scrubbers applied to vehicles fed with fuels containing between 10 and 100% oxygenated products. The performances of catalysts are not very different from those found with gasoline. They remain very good with regard to pollutants not covered by regulations. Furthermore, under normal operating conditions, a catalytic muffler does not produce any supplementary pollutants characteristic of the oxygenated fuels used.

  2. Dépollution des gaz d'échappement des moteurs diesel au moyen de pots catalytiques Depolluting Exhaust Gases from Diesel Engines by Catalytic Mufflers

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    Goldenberg E.


    Full Text Available On présente dans cet article les résultats d'une première série de recherches sur la dépollution des gaz d'échappement des moteurs diesel au moyen de pots catalytiques. L'efficacité des catalyseurs à base de platine pour l'oxydation du monoxyde de carbone et des hydrocarbures imbrûlés a pu être établie par des essais sur banc moteur et sur véhicule. L'emploi de certaines phases actives à base de métaux non nobles permet d'autre part d'abaisser la température de début d'oxydation des particules de suie de 380 à 250 °C environ, avec, entre 250 et 350 °C, élimination de 15 à 20 % des produits piégés. L'essai de divers media filtrants a mis en évidence l'importance des phénomènes d'adsorption des revêtements en alumine et a orienté la recherche vers de nouveaux supports pour filtres catalytiques. This article describes the results of a first series of research on the depollution of exhaust gases from diesel engines by catalytic mufflers. The effectiveness of platinum-base catalysts for the oxidation of carbon monoxide and unburned hydrocarbons was determined by test on an engine test bed and on vehicles on the road. The use of some active non-noble metal phases reduced on the other hand the starting oxidation temperature of soot particulates from 380°C to about 250°C, eliminating 15 to 20% of the trapped products between 250 and 350° C. Tests of different filtering media revealed the importance of adsorption phenomena on alumina coatings and directed research toward new supports for catalytic filters.

  3. 40 CFR 86.312-79 - Dynamometer and engine equipment specifications. (United States)


    ... system must have a single tail pipe. For engines designed for a dual exhaust system, a standard or... standard exhaust system components downstream of the “Y” pipe. For systems with the “Y” pipe upstream of... exhaust pipe downstream of the muffler(s) and from 3 to 20 feet downstream from the exhaust manifold...

  4. Air flow quality analysis of modenas engine exhaust system (United States)

    Shahriman A., B.; Mohamad Syafiq A., K.; Hashim, M. S. M.; Razlan, Zuradzman M.; Khairunizam W. A., N.; Hazry, D.; Afendi, Mohd; Daud, R.; Rahman, M. D. Tasyrif Abdul; Cheng, E. M.; Zaaba, S. K.


    The simulation process being conducted to determine the air flow effect between the original exhaust system and modified exhaust system. The simulations are conducted to investigate the flow distribution of exhaust gases that will affect the performance of the engine. The back flow pressure in the original exhaust system is predicted toward this simulation. The design modification to the exhaust port, exhaust pipe, and exhaust muffler has been done during this simulation to reduce the back flow effect. The new designs are introduced by enlarging the diameter of the exhaust port, enlarge the diameter of the exhaust pipe and created new design for the exhaust muffler. Based on the result obtained, there the pulsating flow form at the original exhaust port that will increase the velocity and resulting the back pressure occur. The result for new design of exhaust port, the velocity is lower at the valve guide in the exhaust port. New design muffler shows that the streamline of the exhaust flow move smoothly compare to the original muffler. It is proved by using the modification exhaust system, the back pressure are reduced and the engine performance can be improve.

  5. Assessment and control design for steam vent noise in an oil refinery. (United States)

    Monazzam, Mohammad Reza; Golmohammadi, Rostam; Nourollahi, Maryam; Momen Bellah Fard, Samaneh


    Noise is one of the most important harmful agents in work environment. Noise pollution in oil refinery industries is related to workers' health. This study aimed to determine the overall noise pollution of an oil refinery operation and its frequency analysis to determine the control plan for a vent noise in these industries. This experimental study performed in control unit of Tehran Oil Refinery in 2008. To determine the noise distributions, environmental noise measurements were carried out by lattice method according to basic information and technical process. The sound pressure level and frequency distribution was measured for each study sources subject separately was performed individually. According to the vent's specification, the measured steam noise characteristics reviewed and compared to the theoretical results of steam noise estimation. Eventually, a double expansion muffler was designed. Data analysis and graphical design were carried out using Excel software. The results of environmental noise measurements indicated that the level of sound pressure was above the national permitted level (85 dB (A)). The Mean level of sound pressure of the studied steam jet was 90.3 dB (L). The results of noise frequency analysis for the steam vents showed that the dominant frequency was 4000 Hz. To obtain 17 dB noise reductions, a double chamber aluminum muffler with 500 mm length and 200 mm diameter consisting pipe drilled was designed. The characteristics of steam vent noise were separated from other sources, a double expansion muffler was designed using a new method based on the level of steam noise, and principle sound frequency, a double expansion muffler was designed.

  6. Commercial advertising and Argumentation efficiency (Say to Maliha (الإعلان التجاري والكفاءة الحجاجية (قل للمليحة أنموذجا

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    Kahdim Jassim Mansur Alazzawi كاظم جاسم منصور العزاوي


    Full Text Available Abstract speech is advertising in all its forms: political, cultural, economic, social, etc., and a means of information for the purpose of delivery of a message aimed at influencing the group of recipients. Commercial and advertising as a form of discourse advertising producer seeks to achieve benefit or financial gain linguistic manner suggestive appeal to the wishes of the segment of society Argumentation and persuasion and drives them to the act of purchase, after giving the advertised goods transformation of material for sale to the value of the properties. The old Arabic poetry was my ad includes a speech to achieve a variety of purposes, it was Raise the submerged and puts a high, and a rich heritage of many stories, story brown nose of the camel and the Annex and many others. As for commercial advertising is better for the Meskeen Aldarmi is represented by lines that recaps the tunnel black Muffleres which does not sell on the Iraqi trader, after around of vintage black Muffleres value to become a girl by Maliha. Find detects Argumentation efficiency owned by the Meskeen Aldarmi has been to ensure recaps, which was behind his success in the city and lure girls to Buy Muffler depressed.

  7. 32 CFR 636.33 - Vehicle safety inspection criteria. (United States)


    ... a muffler in good working order and in constant operation. (10) Mirror—every vehicle, from which the... obstructed by any sign, poster, or other nontransparent material. Windshields and rear windows will not have...

  8. 78 FR 11728 - Pilot Project on NAFTA Trucking Provisions (United States)


    ... that listed the bumper; engine; cabin floor; fuel tank; cab; tires; drive shaft; muffler; chassis; rear door; air tanks; trailer; 5th wheel; and seal/tiedowns, but did not list service brakes, including the...

  9. 75 FR 48941 - Takes of Marine Mammals Incidental to Specified Activities; Piling and Structure Removal in... (United States)


    ... subjects may have been more tolerant of exposures because of motivation to return to a safe location or... power pack would be outfitted with a muffler to reduce in-air noise levels. NMFS has carefully evaluated...

  10. On the whistling of corrugated pipes : effect of pipe length and flow profile

    NARCIS (Netherlands)

    Nakiboglu, G.; Belfroid, S.P.C.; Golliard, J.; Hirschberg, A.


    The study of sound production by internal flows has a broad range of applications such as: monitoring of respiratory sound of intensive care patients, design of vocal folds prosthesis, design of efficient mufflers, control of the stability of large scale natural gas transport, reduction of

  11. Computational analysis of acoustic transmission through periodically perforated interfaces

    Directory of Open Access Journals (Sweden)

    Rohan E.


    Full Text Available The objective of the paper is to demonstrate the homogenization approach applied to modelling the acoustic transmission on perforated interfaces embedded in the acoustic fluid. We assume a layer, with periodically perforated obstacles, separating two half-spaces filled with the fluid. The homogenization method provides limit transmission conditions which can be prescribed at the homogenized surface representing the "limit" interface. The conditions describe relationship between jump of the acoustic pressures and the transversal acoustic velocity, on introducing the "in-layer pressure" which describes wave propagation in the tangent directions with respect to the interface.This approach may serve as a relevant tool for optimal design of devices aimed at attenuation of the acoustic waves, such as the engine exhaust mufflers or other structures fitted with sieves and grillages. We present numerical examples of wave propagation in a muffler-like structure illustrating viability of the approach when complex 3D geometries of the interface perforation are considered.

  12. Seismic Barrier Protection of Critical Infrastructure (United States)


    structures , earthquake mitigation I. Introduction Damage caused by earthquakes to critical structures such as nuclear power plants, regional hospitals...the seismic power drop in dB to magnitude drop using the seismic moment magnitude scale, Mw. In figures 5 and 6, the V-trench structure as modeled...representing geological media and V-shaped muffler borehole / trench component structures . Bottom: In this simple analysis, the power drop observed

  13. Seismic Barrier Protection of Critical Infrastructure from Earthquakes (United States)


    We observe that such barrier structures reduce seismic wave powers by 10 – 40 dB that would otherwise reach the foundation location. Moreover, the... structure composed of opposing boreholes or trenches to mitigate seismic waves from diffracting and traveling in the vertical plane. Computational...seismic wave propagation models suggest that air or fluid filled subsurface V- shaped muffler structures are critical to the redirection and self

  14. Silence is golden : keeping a lid on noise quiets opposition to oilpatch operations

    International Nuclear Information System (INIS)

    Macedo, R.


    Record levels of drilling activity have led to denser well spacings that are often close to residential areas. Many oil and gas operators are now investing in noise suppression technology in order to suppress public concern over noise levels. This article reviewed some new silencing technologies available to the oil and gas industry. Issues concerning permissible sound levels for remote facilities were discussed. Silencing equipment details were presented for turbine exhaust engines, turbo inlet systems, reciprocating engines, and specialty silencers for ventilation systems. Issues concerning acoustical systems and retrofits for existing buildings were also examined. It was noted that a new muffler has been acoustically engineered to provide engine exhaust noise removal along with an internal acoustic treatment to eliminate radiated noise from the muffler shell. The loudest noise source at a compression station is often the engine exhaust of large reciprocating engines. Various computer programs are now available that analyze noise, create models to predict noise levels in decibels for nearby residents, and help to engineer noise control plans. It was concluded that many of the new sound-proofing technologies for the walls and roofs of buildings and enclosures were developed during the design of new compression units built by TransCanada Pipeline on main pipelines across Canada. 2 figs

  15. Distribution of high-temperature (>150 °C) geothermal resources in California (United States)

    Sass, John H.; Priest, Susan S.


    California contains, by far, the greatest geothermal generating capacity in the United States, and with the possible exception of Alaska, the greatest potential for the development of additional resources. California has nearly 2/3 of the US geothermal electrical installed capacity of over 3,000 MW. Depending on assumptions regarding reservoir characteristics and future market conditions, additional resources of between 2,000 and 10,000 MWe might be developed (see e.g., Muffler, 1979).

  16. Acoustic Characterization of Turbochargers and Pipe Terminations


    Tiikoja, Heiki


    In search for quieter engines there is a need for a better understanding of the acoustic properties of engine intake and exhaust system components. Besides mufflers which have the purpose of reducing pressure pulses originating from the internal combustion (IC) engine, there are many components in a modern car exhaust and intake system, e.g., air-filters, coolers, catalytic converters, particulate filters - all having an effect on the pressure pulses or sound field in the system. In this work...

  17. Eyes Abroad

    Institute of Scientific and Technical Information of China (English)


    China International Fair for Investment & Trade helps push Chinese companies’ overseas ambitions A bustle of Chinese businesspeople roams the vast exhibition hall of the China International Fair for Investment & Trade(CIFIT) looking for opportunities to build cross-border scale. Among them is Zhou Meimei,Business Development Manager of the Shanghai Yiyang Electric Machinery Co. Ltd.,a manufacturer of mufflers and ventilation equipment. Although this was her first time attending the fair,Zhou did not go home empty-handed.

  18. A Hybrid approach for aeroacoustic analysis of the engine exhaust system


    Sathyanarayana, Y; Munjal, ML


    This paper presents a new hybrid approach for prediction of noise radiation from engine exhaust systems. It couples the time domain analysis of the engine and the frequency domain analysis of the muffler, and has the advantages of both. In this approach, cylinder/cavity is analyzed in the time domain to calculate the exhaust mass flux history at the exhaust valve by means of the method of characteristics, avoiding the tedious procedure of interpolation at every mesh point and solving a number...

  19. Methanator fueled engines for pollution control (United States)

    Cagliostro, D. E.; Winkler, E. L.


    A methanator fueled Otto-cycle engine is compared with other methods proposed to control pollution due to automobile exhaust emissions. The comparison is made with respect to state of development, emission factors, capital cost, operational and maintenance costs, performance, operational limitations, and impact on the automotive industries. The methanator fueled Otto-cycle engine is projected to meet 1975 emission standards and operate at a lower relative total cost compared to the catalytic muffler system and to have low impact. Additional study is required for system development.

  20. Cleaner fuels for the improvement of air quality

    International Nuclear Information System (INIS)

    Catani, R.; Marchionna, M.; Rossini, S.


    Harder standards of quality of the air and the consequent limits on the emissions involve the necessity to adopt various measures: programs for inspection/maintenance, technological advance on motors and catalytic mufflers and the reformulation of fuel. This last one is not the only solution but plays a remarkable role, because it has an immediate effect on the quality of the air. As result of that, the present paper explains the main variations that will regard the composition of ben zine and diesel oil

  1. Effect of duct shape, Mach number, and lining construction on measured suppressor attenuation and comparison with theory (United States)

    Olsen, W. A.; Krejsa, E. A.; Coats, J. W.


    Noise attenuation was measured for several types of cylindrical suppressors that use a duct lining composed of honeycomb cells covered with a perforated plate. The experimental technique used gave attenuation data that were repeatable and free of noise floors and other sources of error. The suppressor length, the effective acoustic diameter, suppressor shape and flow velocity were varied. The agreement among the attenuation data and two widely used analytical models was generally satisfactory. Changes were also made in the construction of the acoustic lining to measure their effect on attenuation. One of these produced a very broadband muffler.

  2. Cancelation and its simulation using Matlab according to active noise control case study of automotive noise silencer (United States)

    Alfisyahrin; Isranuri, I.


    Active Noise Control is a technique to overcome noisy with noise or sound countered with sound in scientific terminology i.e signal countered with signals. This technique can be used to dampen relevant noise in accordance with the wishes of the engineering task and reducing automotive muffler noise to a minimum. Objective of this study is to develop a Active Noise Control which should cancel the noise of automotive Exhaust (Silencer) through Signal Processing Simulation methods. Noise generator of Active Noise Control is to make the opponent signal amplitude and frequency of the automotive noise. The steps are: Firstly, the noise of automotive silencer was measured to characterize the automotive noise that its amplitude and frequency which intended to be expressed. The opposed sound which having similar character with the signal source should be generated by signal function. A comparison between the data which has been completed with simulation calculations Fourier transform field data is data that has been captured on the muffler (noise silencer) Toyota Kijang Capsule assembly 2009. MATLAB is used to simulate how the signal processing noise generated by exhaust (silencer) using FFT. This opponent is inverted phase signal from the signal source 180° conducted by Instruments of Signal Noise Generators. The process of noise cancelation examined through simulation using computer software simulation. The result is obtained that attenuation of sound (noise cancellation) has a difference of 33.7%. This value is obtained from the comparison of the value of the signal source and the signal value of the opponent. So it can be concluded that the noisy signal can be attenuated by 33.7%.

  3. Study on Control of Brain Temperature for Brain Hypothermia Treatment (United States)

    Gaohua, Lu; Wakamatsu, Hidetoshi

    The brain hypothermia treatment is an attractive therapy for the neurologist because of its neuroprotection in hypoxic-ischemic encephalopathy patients. The present paper deals with the possibility of controlling the brain and other viscera in different temperatures from the viewpoint of system control. It is theoretically attempted to realize the special brain hypothermia treatment to cool only the head but to warm the body by using the simple apparatus such as the cooling cap, muffler and warming blanket. For this purpose, a biothermal system concerning the temperature difference between the brain and the other thoracico-abdominal viscus is synthesized from the biothermal model of hypothermic patient. The output controllability and the asymptotic stability of the system are examined on the basis of its structure. Then, the maximum temperature difference to be realized is shown dependent on the temperature range of the apparatus and also on the maximum gain determined from the coefficient matrices A, B and C of the biothermal system. Its theoretical analysis shows the realization of difference of about 2.5°C, if there is absolutely no constraint of the temperatures of the cooling cap, muffler and blanket. It is, however, physically unavailable. Those are shown by simulation example of the optimal brain temperature regulation using a standard adult database. It is thus concluded that the surface cooling and warming apparatus do no make it possible to realize the special brain hypothermia treatment, because the brain temperature cannot be cooled lower than those of other viscera in an appropriate temperature environment. This study shows that the ever-proposed good method of clinical treatment is in principle impossible in the actual brain hypothermia treatment.

  4. Geothermal energy from deep sedimentary basins: The Valley of Mexico (Central Mexico) (United States)

    Lenhardt, Nils; Götz, Annette E.


    The geothermal potential of the Valley of Mexico has not been addressed in the past, although volcaniclastic settings in other parts of the world contain promising target reservoir formations. A first assessment of the geothermal potential of the Valley of Mexico is based on thermophysical data gained from outcrop analogues, covering all lithofacies types, and evaluation of groundwater temperature and heat flow values from literature. Furthermore, the volumetric approach of Muffler and Cataldi (1978) leads to a first estimation of ca. 4000 TWh (14.4 EJ) of power generation from Neogene volcanic rocks within the Valley of Mexico. Comparison with data from other sedimentary basins where deep geothermal reservoirs are identified shows the high potential of the Valley of Mexico for future geothermal reservoir utilization. The mainly low permeable lithotypes may be operated as stimulated systems, depending on the fracture porosity in the deeper subsurface. In some areas also auto-convective thermal water circulation might be expected and direct heat use without artificial stimulation becomes reasonable. Thermophysical properties of tuffs and siliciclastic rocks qualify them as promising target horizons (Lenhardt and Götz, 2015). The here presented data serve to identify exploration areas and are valuable attributes for reservoir modelling, contributing to (1) a reliable reservoir prognosis, (2) the decision of potential reservoir stimulation, and (3) the planning of long-term efficient reservoir utilization. References Lenhardt, N., Götz, A.E., 2015. Geothermal reservoir potential of volcaniclastic settings: The Valley of Mexico, Central Mexico. Renewable Energy. [in press] Muffler, P., Cataldi, R., 1978. Methods for regional assessment of geothermal resources. Geothermics, 7, 53-89.

  5. Exhaust gas recirculation apparatus for internal combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Shigemori, M; Eguchi, N


    An exhaust gas recirculation device to reduce nitrogen oxides emission from internal combustion engines is described. The recirculation is achieved by employing a tube connecting between the exhaust pipe and intake tube. A throttle valve is installed within the exhaust pipe between the muffler and recirculation tube, and regulated by exhaust gas temperature. Whenever the gas temperature is high, the valve closes and increases the gas flow to the intake tube. A temperature sensor is installed within the exhaust pipe and controls a solenoid or magnetic air valve linking to the throttle valve through a relay. The recirculation tube can be cooled by a fan to improve the engine power.

  6. Study on ventilation and noise reduction in the main transformer room in indoor substation

    Directory of Open Access Journals (Sweden)

    Hu Sheng


    Full Text Available The noise emission should be considered in the ventilation and cooling design for the main transformer room of indoor substation. In this study, based on Soundplan software, effects of four common ventilation and cooling schemes on the cooling and sound insulation were compared. The research showed that the region with low noise requirement, the ventilation could be set on the outer wall or on the door of the main transformer room, while the region with high noise requirement, air inlet muffler or ventilation through the cable interlayer under the main transformer room must be used. All of the four kinds of ventilation schemes, ventilation through the cable interlayer is the best in cooling and noise reduction.

  7. A Low Cost Ferritic Stainless Steel Microalloyed by Higher Nb for Automotive Exhaust System (United States)

    Chen, Erhu; Wang, Xuelin; Shang, Chengjia

    Automotive engine exhaust gas after combustion of fuel, and the gas will be liquefied in the rear of automotive exhaust system. A lot of corrosive anions existing in the condensate make corrosion of the exhaust system materials. Therefore, once pitting perforation, automotive exhaust system will fail directly. In 1980s, automotive exhaust manifold was made of Si-Mo ductile iron, mufflers and the tail pipe were made of carbon steel or aluminized steel. But with higher emission standards carried out, the improvement of engine performance and the higher exhaust temperature as well as the needs of the automotive light-weighting, we need the higher corrosion resistance of the material for automotive exhaust systems to meet the requirements.

  8. Preparation of activated carbon from banana peel waste for reducing air pollutant from motorcycle muffler

    Directory of Open Access Journals (Sweden)

    Chafidz Achmad


    Full Text Available The exhaust gas or emission from motor vehicle contains various pollutants and some of them are toxic and very harmful for human health. In the present work, we prepared an activated carbon to reduce the toxic pollutants (via adsorption process from the exhaust gas of the motor vehicle (particularly motorcycle in this work. The activated carbon was prepared from local banana peel which considered as an agricultural waste without economic value. To prepare the activated carbon, banana peel was carbonized using furnace at 500°C. Then the resulted carbon was activated using chemical activation with ZnCl2 and physical activation with either microwave (300 W or furnace (700°C. The prepared activated carbon was then characterized using Scanning Electron Microscope (SEM and Fourier Transform Infrared (FT-IR analysis. The SEM result showed that the pore of microwave induced ZnCl2 activated carbon (ACM was larger than the pore of virgin char/carbon and furnace induced ZnCl2 activataed carbon (ACF. The FT-IR spectrum of ACM showed some peaks at 3408.59 cm-1, 1589.25 cm-1, and 1093.63 cm-1. They are assigned to O-H stretching, C=O stretching, and C-OH stretching. Additionally, the adsorption performance of the prepared activation carbon to reduce the pollutants concentration (i.e. CO and CH from the exhaust gas of motor vehicle was investigated. The results showed that the activated carbon induced by microwave and ZnCl2 activation (ACM gave the best result. The adsorption or removal efficiency of gas CO reached approximately 97.64 %vol.

  9. Observational learning and workplace safety: the effects of viewing the collective behavior of multiple social models on the use of personal protective equipment. (United States)

    Olson, Ryan; Grosshuesch, Ariel; Schmidt, Sara; Gray, Mary; Wipfli, Bradley


    The current project evaluated the effects of the collective behavior of multiple social models on the use of personal protective equipment (PPE). Prior to completing a simulated baggage-screening task, participants (N=64) watched a scripted training video that included three confederate trainees. Participants were randomly assigned to one of four manipulations, where different proportions of confederates were shown putting on over-ear sound mufflers before starting the task (0, 1, 2, or 3). White noise played at 70 decibels in the test room, and PPE use was observed unobtrusively through a lab window at five time intervals. The mean intervals of PPE use generally increased as the number of positive social models increased (0=0.63, 1=0.50, 2=1.25, 3=3.06), and differences between groups were significant [chi(2) (3, N=64)=14.92, preinforcement for compliance.

  10. NASA ISS Portable Fan Assembly Acoustics (United States)

    Boone, Andrew; Allen, Christopher S.; Hess, Linda F.


    The Portable Fan Assembly (PFA) is a variable speed fan that can be used to provide additional ventilation inside International Space Station (ISS) modules as needed for crew comfort or for enhanced mixing of the ISS atmosphere. This fan can also be configured with a Shuttle era lithium hydroxide (LiOH) canister for CO2 removal in confined areas partially of fully isolated from the primary Environmental Control and Life Support System (ECLSS) on ISS which is responsible for CO2 removal. This report documents noise emission levels of the PFA at various speed settings and configurations. It also documents the acoustic attenuation effects realized when circulating air through the PFA inlet and outlet mufflers and when operating in its CO2 removal configuration (CRK) with a LiOH canister (sorbent bed) installed over the fan outlet.

  11. Research highlights : study of the noise generated by heat pumps in residential areas

    International Nuclear Information System (INIS)

    Rousseau, J.


    Rising energy costs and aggressive marketing played a major role in the substantial increase in the number of domestic heat pumps installed. As a rule, heat pumps are connected to the heating and ventilation systems on the outside of the house. Whether the heat pump is equipped with an integrated compressor or not, it creates noise. The noise is generated by the powerful fan designed to cool all the coils, and also by the compressor itself and the circulation of the refrigerant gas. Some municipalities received so many complaints on this topic that they are considering adopting noise bylaws. The first objective of the research undertaken by Canada Mortgage and Housing Corporation on heat pumps in residential areas was to analyze the noise pollution mode of commonly used heat pumps. A study of a simple noise reduction device was performed, and the extent to which it should be used. Finally, there had to be no reduction of the thermal capacities of the pumps. Phase 1 of the study took place between May and August 1990, in the area of Quebec City. A total of 125 heat pumps were identified. The four major manufacturers were Trane, Carrier, York, and Lennox. Initial sound pressure levels measurements were made at one metre from the unit, for 80 such units, respecting the ratio by brands in the sample of 125. A detailed global noise measurement determined the sound power of each pump. A detailed muffler feasibility study was then conducted, using a Trane heat pump. The results of the study indicated that heat pumps were a major source of continuous noise in low and mid-density areas. It was discovered that a noise attenuation device could always be built around heat pumps, which needed to be installed as close as possible to the casing of the heat pump. It is not possible to design a device to fit each and every heat pump, the design is specific to the dimensions and characteristics of each model of heat pump. The thermal performance of the pumps will not be affected by

  12. CAE for the development of two-wheeled vehicles. Nirinsha kaihatsu no tame no CAE

    Energy Technology Data Exchange (ETDEWEB)

    Hirose, T. (Suzuki Motor Co. Ltd., Shizuoka (Japan))


    Applications of CAE to the development of two-wheeled vehicles were outlined. The performance estimation program for 4-cycle engines featured by its easy execution was presented illustrating an estimation model and estimated results, and the FEM generator for strength/rigidity analysis CAE indicating analytical examples of a piston and frame which is featured by easy formation of models and easy execution of advanced analyses by beginners. The vibration analysis system to estimate exciting forces from engine specifications and to estimate vibration levels of bodies with FEM models was also presented together with the estimation system of rider's vibration sensitivity. Furthermore, the noise suppression/ exhaust pressure calculation program to support muffler designs by simultaneous calculation was presented together with the thermal flow analysis program featured by easy calculation with more suitable models illustrating the analytical example of thermal flow in a large luggage box. 7 refs., 15 figs.

  13. Retrofitting reciprocating compressors for noise control

    International Nuclear Information System (INIS)

    Frank, L.; Qualfe, R.


    The Alberta Energy Resources Conservation Board recently enacted their noise control directive ID 88-1. The effects of this regulation on the operation of an oil and gas facility are discussed, and a specific case history is presented to provide a disciplined strategy for noise attenuation retrofits. An investigation was carried out into sound sources at a reciprocating compressor gas plant, revealing several sound sources: engine exhaust stacks, engine exhaust silencer shells, direct-drive fan cooler inlets, direct drive fan cooler outlets, aerial cooler inlets and aerial cooler outlets. Details are presented of the investigative techniques and order-ranking of sources by decibel level. When controlling engine exhaust noise, silencers or mufflers are the preferred treatment. Choice of type (reactive or absorptive) and specification of acoustical performance of a silencer are discussed. The gas plant achieved noise reductions of 6-13 dB, measured at affected residences, through the use of engine exhaust silencers. 4 figs., 2 tabs

  14. Traffic noise control of a city

    International Nuclear Information System (INIS)

    Ahmed, A.; Khan, J.A.; Lakhani, A.H.; Hyder, F.G.; Shamsuddin, S.A.


    Long exposure to noise due to traffic affects our health and comfort. A noise level up to 45 dB is acceptable for the buildings in the city. A traffic noise study was conducted in Karachi at places of high traffic flow. The noise level was between 75-85 dB. Residential and commercial buildings had sound level up to 79 dB. Reducing vehicle noise by using proper muffler and acoustic treatment should first control traffic noise. Then noise can be reduced by 10-15 dB by constructing barriers of wood or concrete along roadside. Barrier height for sound attenuation can be found from Fresnel Number. The barrier reduces noise better if width at the top is increased and an inward bend of 60 degree is placed at the top. Where feasible a 4-5 meter high concrete barrier is recommended otherwise the nearby buildings from the road should be insulated and acoustically treated. (author)

  15. Reduction of Discrete-Frequency Fan Noise Using Slitlike Expansion Chambers

    Directory of Open Access Journals (Sweden)

    Akira Sadamoto


    Full Text Available As is generally known, discrete-frequency noises are radiated from fans due to rotor-stator interaction. Their fundamental frequency is the blade-passage frequency, which is determined by the number of rotor blades and their rotating speeds. To reduce such noises, several types of silencers have been designed. Among them, the authors noted a slitlike expansion chamber (hereafter referred to as slit, for simplicity and have studied its performance. A slit is a simple expansion chamber with a very short axial length that is placed in a duct. A slit with a circular cross-section that is concentric with a circular duct may be studied using the same interpretation as is used for a side-branch resonator muffler (closed-end tube connected to a duct; that is, the resonant frequency of a slit depends on its depth (with an open-end correction. It is expected, hence, that a slit might be applicable as a simple and axially compact silencer that is effective on discrete-frequency noises. In this article, the properties of a slit are introduced, and the applicability of a slit to actual rotating machinery is described using experimental data.

  16. Influence of an Optimized Thermoelectric Generator on the Back Pressure of the Subsequent Exhaust Gas System of a Vehicle (United States)

    Kühn, Roland; Koeppen, Olaf; Kitte, Jens


    Numerous research projects in automotive engineering focus on the industrialization of the thermoelectric generator (TEG). The development and the implementation of thermoelectric systems into the vehicle environment are commonly supported by virtual design activities. In this paper a customized simulation architecture is presented that includes almost all vehicle parts which are influenced by the TEG (overall system simulation) but is nevertheless capable of real-time use. Moreover, an optimized planar TEG with minimum nominal power output of about 580 W and pressure loss at nominal conditions of 10 mbar, synthesized using the overall system simulation, and the overall system simulation itself are used to answer a generally neglected question: What influence does the position of a TEG have on the back pressure of the subsequent exhaust gas system of the vehicle? It is found that the influence of the TEG on the muffler is low, but the catalytic converter is strongly influenced. It is shown that the TEG can reduce the back pressure of an exhaust gas system so much that its overall back pressure is less than the back pressure of a standard exhaust gas system.

  17. Management and use of DOE-provided discretionary funds. Progress report, January-December 1980

    Energy Technology Data Exchange (ETDEWEB)


    The first section of this report presents brief summaries of the final reports for each Univ. of Illinois/Office of Energy Research project support by DOE in 1980, namely: An Assessment of the Impact of Commission Regulation on Prices; Radiative Collision Lasers; NO/sub x/ Decomposition in a Catalytic Muffler; Fuel/Air Control System for Catalytic Combustion Driven Stirling Engines - A Feasibility Study; Regional Environmental-Economic Optimization Models for Evaluating Policies Which Affect the Development of the Electric Power Industry in the Midwest; Analysis of Public Attitudes on Nuclear Power; Impacts of Energy Shortages Upon East Urbana, 1980: a Re-Study and Analysis; Alcohol energy Systems for Corn Farms; Feasibility of Greenhouses Heated with Surface Application of Power Plant Cooling Water; and Replacement of Petroleum Fuels with Alcohol. The second section deals with the proposed program for 1981 and use of the discretionary funds, specifically to encourage a distinguished multi-disciplinary group in Engineering Materials to direct their attention to the materials problems that are associated with advanced techniques of coal utilization, are described. A third section, Appendix A contains the complete program reports as submitted by the investigators. (MCW)

  18. Estimate of the Geothermal Energy Resource in the Major Sedimentary Basins in the United States (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Esposito, A.; Porro, C.; Augustine, C.; Roberts, B.


    Because most sedimentary basins have been explored for oil and gas, well logs, temperatures at depth, and reservoir properties such as depth to basement and formation thickness are well known. The availability of this data reduces exploration risk and allows development of geologic exploration models for each basin. This study estimates the magnitude of recoverable geothermal energy from 15 major known U.S. sedimentary basins and ranks these basins relative to their potential. The total available thermal resource for each basin was estimated using the volumetric heat-in-place method originally proposed by (Muffler, 1979). A qualitative recovery factor was determined for each basin based on data on flow volume, hydrothermal recharge, and vertical and horizontal permeability. Total sedimentary thickness maps, stratigraphic columns, cross sections, and temperature gradient information was gathered for each basin from published articles, USGS reports, and state geological survey reports. When published data were insufficient, thermal gradients and reservoir properties were derived from oil and gas well logs obtained on oil and gas commission databases. Basin stratigraphy, structural history, and groundwater circulation patterns were studied in order to develop a model that estimates resource size, temperature distribution, and a probable quantitative recovery factor.

  19. Reduction of the suction losses through reed valves in hermetic reciprocating compressors using a magnet coil (United States)

    Hopfgartner, J.; Posch, S.; Zuber, B.; Almbauer, R.; Krischan, K.; Stangl, S.


    Reed valves are widely used in hermetic reciprocating compressors and are responsible for a large part of the thermodynamic losses. Especially, the suction valve, which is opened nearly during the whole suction stroke, has a big potential for improvement. Usually, suction valves are opened only by vacuum created by the moving piston and should be closed before the compression stroke starts to avoid a reversed mass-flow through the valve. Therefore, the valves are prestressed, which results on the other hand in a higher flow resistance. In this work, a suction valve is investigated, which is not closed by the preload of the valve but by an electromagnetic coil located in the suction muffler neck. Shortly before the piston reaches its bottom dead centre, voltage is applied to the coil and a magnetic force is generated which pulls the valve shut. Thereby, the flow resistance through the valve can be reduced by changing the preload on the reed valve because it is no longer needed to close the valve. The investigation of this adapted valve and the electromagnetic coil is firstly done by numerical simulations including fluid structure interactions of the reed valves of a reciprocating compressor and secondly by experiments made on a calorimeter test bench.

  20. Characterization of Cr/Bentonite and HZSM-5 Zeolite as Catalysts for Ethanol Conversion to Biogasoline

    Directory of Open Access Journals (Sweden)

    Robert Ronal Widjaya


    Full Text Available In this research it has been done characterization on Cr/Bentonit and Zeolit HZSM-5 catalysts for ethanol catalytic process to biogasoline (equal to gasoline. Cr/Bentonit has high acidity and resistant to a lot of moisture, so in addition to being able to processing feed which a lot of moisture (>15% from ethanol-water mixture, also it is not easy deactivated. Cr/Bentonit which is then used as the catalyst material on the process of ethanol conversion to be biogasoline and the result was compared with catalyst HZSM-5 zeolite. Several characterization methods: X-ray diffraction, Brunauer Emmett Teller (BET, thermogravimetry analysis (TGA, and catalyst activity tests using catalytic Muffler instrument and gas chromatography-mass spectrometry (GC-MS for product analysis were performed on both catalysts. From acidity measurement, it is known that acidity level of Cr/Bentonit is the highest and also from XRD result, it is known there is shift for 2theta in Cr/Bentonit, which indicates that Cr-pillar in the Bentonite can have interaction. It is also supported by BET data that shows the addition of specific surface are in Cr/Bentonite compared with natural Bentonite before pillarization. Futhermore catalyst activity test produced the results, analyzed by GC-MS, identified as butanol and also possibly formed hexanol, decane, dodecane, undecane, which are all included in gasoline range (C4 until C12.

  1. Exhaust purification of DI spark ignition engines by means of barrier discharge. Final report; Abgasreinigung von DI-Ottomotoren durch Barrierenentladungen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Wolters, P.; Lepperhoff, G.; Baumgarten, H.; Scharr, D.; Neff, W.; Trompeter, F.J.; Seiwert, S.; Kamp, J.; Pochner, K.


    Dielectric barrier discharge offers the advantage to excite and dissociate molecules in the exhaust gas stream. Those dissociated and excited species are oxidizing or reducing harmful exhaust gas components. The advantage of a plasma chemical system in comparison to a catalytic converter is the instantaneous activity at ambient temperature from the turn key of the engine. The investigations presented here focus on the plasma chemical oxidation of hydrocarbons in the exhaust gas stream during cold start conditions. The article concerns the design and development of a plasma system in order to decrease the hydrocarbon emissions from engine start till catalyst light off. Vehicle results in the new European driving cycle show a hydrocarbon conversion of more than 43% in the first 11 seconds from engine start. In this period nearly all types of hydrocarbon were reduced. The exhaust back pressure of the sytem is comparable to the conventional muffler. Further system improvement can be achieved by an optimization of the disk electrode design. [German] Um die strengen zukuenftigen Schadstoffemissionsgrenzwerte von Ottomotoren in der EU oder den USA einhalten zu koennen, werden derzeit weltweit auch plasmachemische Methoden zur Abgasnachbehandlung in Betracht gezogen. Insbesondere nichtthermische Atmosphaerendruck-Gasentladungen, wie die Barrierenentladung, zeigen Chancen auf, die Betriebsbedingungen und Grenzen gegenwaertiger katalytischer Techniken zu erweitern. In diesem Vorhaben wurde die Barrierenentladung zur plasmachemischen Umsetzung von Schadstoffen im Abgas eines mager betriebenen Ottomotors im Serienautomobil untersucht, um das Potential zur Abgasreinigung zu bewerten und auszuweiten. (orig.)

  2. Performance of school bus retrofit systems: ultrafine particles and other vehicular pollutants. (United States)

    Zhang, Qunfang; Zhu, Yifang


    This study evaluated the performance of retrofit systems for diesel-powered school buses, a diesel oxidation catalyst (DOC) muffler and a spiracle crankcase filtration system (CFS), regarding ultrafine particles (UFPs) and other air pollutants from tailpipe emissions and inside bus cabins. Tailpipe emissions and in-cabin air pollutant levels were measured before and after retrofitting when the buses were idling and during actual pick-up/drop off routes. Retrofit systems significantly reduced tailpipe emissions with a reduction of 20-94% of total particles with both DOC and CFS installed. However, no unequivocal decrease was observed for in-cabin air pollutants after retrofitting. The AC/fan unit and the surrounding air pollutant concentrations played more important roles for determining the in-cabin air quality of school buses than did retrofit technologies. Although current retrofit systems reduce children's exposure while waiting to board at a bus station, retrofitting by itself does not protect children satisfactorily from in-cabin particle exposures. Turning on the bus engine increased in-cabin UFP levels significantly only when the wind blew from the bus' tailpipe toward its hood with its windows open. This indicated that wind direction and window position are significant factors determining how much self-released tailpipe emissions may penetrate into the bus cabin. The use of an air purifier was found to remove in-cabin particles by up to 50% which might be an alternative short-to-medium term strategy to protect children's health.

  3. Twentieth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)



    PREFACE The Twentieth Workshop on Geothermal Reservoir Engineering, dedicated to the memory of Professor Hank Ramey, was held at Stanford University on January 24-26, 1995. There were ninety-five registered participants. Participants came from six foreign countries: Japan, Mexico, England, Italy, New Zealand and Iceland. The performance of many geothermal reservoirs outside the United States was described in several of the papers. Professor Roland N. Horne opened the meeting and welcomed visitors to the campus. The key note speaker was Marshall Reed, who gave a brief overview of the Department of Energy's current plan. Thirty-two papers were presented in the technical sessions of the workshop. Technical papers were organized into eleven sessions concerning: field development, modeling, well tesubore, injection, geoscience, geochemistry and field operations. Session chairmen were major contributors to the workshop, and we thank: Ben Barker, Bob Fournier, Mark Walters, John Counsil, Marcelo Lippmann, Keshav Goyal, Joel Renner and Mike Shook. In addition to the technical sessions, a panel discussion was held on ''What have we learned in 20 years?'' Panel speakers included Patrick Muffler, George Frye, Alfred Truesdell and John Pritchett. The subject was further discussed by Subir Sanyal, who gave the post-dinner speech at the banquet. The Workshop was organized by the Stanford Geothermal Program faculty, staff, and graduate students. We wish to thank our students who operated the audiovisual equipment. Shaun D. Fitzgerald Program Manager

  4. The Role of Heat in the Development of Energy and Mineral Resources in the Northern Basin and Range Province (United States)

    Armstrong, Richard L.

    It is now just over a decade since OPEC escalated the price of oil and triggered a flurry of alternate energy research and changing energy consumption practices. One scientific impact of that historical economic turning point was the launching of geothermal exploration programs of unprecedented intensity that focused on Cenozoic volcanic rocks and active, as well as fossil, geothermal systems. The good science that was already being done on such rocks and systems was both accelerated and diluted by government-funded research and energy industry exploration efforts. After the initial flood of detailed reports, gray literature, and documents interred in company files, we are observing the appearance of syntheses of just what happened and what progress was achieved during the geothermal boom (which has now wilted to the quiet development of a few most promising sites). Recent examples of geothermal synthesis literature include the book Geothermal Systems by L. Rybach and L.J. Muffler (John Wiley, New York, 1981), publications like Oregon Department of Geology and Mineral Industries Paper 15 by G.R. Priest et al. (1983) entitled “Geology and geothermal resources of central Oregon Cascade range,” and informative maps like the U.S. Geological Survey series summarizing late Cenozoic volcanic rock distribution and age (R.G. Luedke and R.L. Smith, maps 1-1091 A to D, 1979 to 1982), and state and regional geothermal resources maps (NOAA National Geophysical Data Center, 1977-1982). The book under review here is part of this second literature wave, a useful primary reference, collection of syntheses, and literature guide but certainly not unique.

  5. Demonstration of high temperature thermoelectric waste heat recovery from exhaust gases of a combustion engine

    Energy Technology Data Exchange (ETDEWEB)

    Trottmann, Matthias; Weidenkaff, Anke; Populoh, Sascha; Brunko, Oliver; Veziridis, Angelika; Bach, Christian; Cabalzar, Urs [Empa, Duebendorf (Switzerland)


    The energy efficiency of passenger cars becomes increasingly important due to a growing awareness in terms of climate change and shortages of resources associated with rising fuel prices. In addition to the efforts towards the optimization of the engine's internal efficiency, waste heat recovery is the main objective. In this respect, thermoelectric (TE) devices seem to be suited as heat recuperation systems. Thermoelectric generators allow for direct transformation of thermal into electrical energy. In order to thoroughly investigate this type of recovery system a TE demonstrator was mounted on the muffler of a VW Touran and tested. The waste heat of the exhaust gas was converted into electricity with a conversion rate of {proportional_to}. 3.5%. The limiting factor was the low thermal stability of the commercial modules used in this pre-study to elaborate reference values. Thermoelectric modules based on sustainable and temperature-stable materials are being developed to improve the measured values. A thermoelectric test generator with perovskite-type oxide modules was constructed confirm the function and stability at elevated temperatures. Despite all the advantages of this material class, the TE performance is still to be improved. A quantitative measure of a material's TE performance is the temperature-independent Figure of Merit ZT. ZT increases with decreasing thermal and increasing electrical conductivity. An approach to thermal conductivity reduction is nanostructuring of the material. The Ultrasonic Spray Combustion (USC) technique allows to produce powders with a grain size on the nanoscale and was tested in this study. (orig.)

  6. Potemkin Ranch : blending industrial buildings into their surrounding environments is a good idea that may yet catch on

    International Nuclear Information System (INIS)

    Stastny, P.


    The oil and gas industry is attempting to blend into their surroundings in order to improve relations with landowners. This article presented details of a 7.5 million-cubic-feet-per-day gas facility disguised as a cattleman's ranch through the use of convincing facades. The compressor unit is disguised as a ranch house, while the dehydration unit looks like a carriage house. Electrical controls are housed in a separate bunkhouse. In 2001, a skid-mounted refrigeration unit was added and enclosed in a barn facade. The total cost over and above a typical metal-clad gas facility was approximately $100,000, almost 4 per cent of the total facility cost of $2.5 million. While some companies have been using colour to camouflage facilities for many years, other companies have placed more importance on noise suppression, which can add 10 to 20 per cent to the cost of each building. In order to improve noise control, some facilities are now being constructed in topographical low spots with insulated enclosures and hospital-grade mufflers. Pioneer Canada has recently camouflaged a gas facility to mimic a farm which was subsequently fitted with standard noise attenuation. The company's new standard of noise reduction has resulted in additional costs of up to $200,000 per site. Landowners have commented favourably on Pioneer Canada's camouflage efforts. It was concluded that as land access becomes an even bigger issue in some plays, operators may increasingly use architectural features to make their facilities less obtrusive. 5 figs

  7. Potemkin Ranch : blending industrial buildings into their surrounding environments is a good idea that may yet catch on

    Energy Technology Data Exchange (ETDEWEB)

    Stastny, P.


    The oil and gas industry is attempting to blend into their surroundings in order to improve relations with landowners. This article presented details of a 7.5 million-cubic-feet-per-day gas facility disguised as a cattleman's ranch through the use of convincing facades. The compressor unit is disguised as a ranch house, while the dehydration unit looks like a carriage house. Electrical controls are housed in a separate bunkhouse. In 2001, a skid-mounted refrigeration unit was added and enclosed in a barn facade. The total cost over and above a typical metal-clad gas facility was approximately $100,000, almost 4 per cent of the total facility cost of $2.5 million. While some companies have been using colour to camouflage facilities for many years, other companies have placed more importance on noise suppression, which can add 10 to 20 per cent to the cost of each building. In order to improve noise control, some facilities are now being constructed in topographical low spots with insulated enclosures and hospital-grade mufflers. Pioneer Canada has recently camouflaged a gas facility to mimic a farm which was subsequently fitted with standard noise attenuation. The company's new standard of noise reduction has resulted in additional costs of up to $200,000 per site. Landowners have commented favourably on Pioneer Canada's camouflage efforts. It was concluded that as land access becomes an even bigger issue in some plays, operators may increasingly use architectural features to make their facilities less obtrusive. 5 figs.

  8. On modelling, simulation and measurement of fluid power pumps and pipelines

    International Nuclear Information System (INIS)

    Weddfelt, K.


    Pressure ripple in fluid power systems is often considered to be a nuisance. It is a major reason for vibrations and noise emission but can also cause functional problems, in extreme causes even fatigue and breakdown of pipes and connections. In order to examine this problem both the sources of pressure ripple and its transmission properties must be considered. A major source of pressure ripple in fluid power systems is positive displacement pumps, a component which is actually a source of flow ripple. A positive displacement pump can be characterized and modelled as a flow source with an internal source impedance. Special measurement techniques must be developed in order to determine these source properties experimentally. Pressure and flow ripple propagate through the pipeline of a fluid power system as waves. When the impedance of the system changes, part of the energy in the wave is being transmitted while the remaining part is reflected. Therefore, the mechanism for standing waves to occur is present, causing resonances and possibly very large pressure pulsations at certain frequencies. Destructive interference between these waves can be used to design so-called reactive attenuators, similar to an automobile muffler, which can be used to acoustically separate the source of flow ripple from the rest of the fluid power system. A mathematical model of wave transmission in pipelines is of fundamental importance to the design of acoustical sound systems. It is of equal importance when modelling and measuring the source characteristics of fluid power pumps. Such a mathematical model must include the transmission and reflection of waves as well as the frequency-dependent losses from viscous friction in the fluid. (au)

  9. Technical report for a fluidless directional drilling system demonstrated at Solid Waste Storage Area 6 shallow buried waste sites

    International Nuclear Information System (INIS)


    The purpose of the research was to demonstrate a fluidless directional drilling and monitoring system (FDD) specifically tailored to address environmental drilling concerns for shallow buried wasted. The major concerns are related to worker exposure, minimizing waste generation, and confining the spread of contamination. The FDD is potentially applicable to Environmental Restoration (ER) activities for the Oak Ridge National Laboratory Waste Area Grouping 6 (WAG 6) shallow buried waste disposed in unlined trenches. Major ER activities for directional drilling are to develop a drilling system for leachate collection directly beneath trenches, and to provide localized control over leachate release to the environment. Other ER FDD activities could include vadose zone and groundwater monitoring of contaminant transport. The operational constraints pointed the research in the direction of purchasing a steerable impact hammer, or mole, manufactured by Steer-Rite Ltd. of Racine, Wisconsin. This drill was selected due to the very low cost ($25,000) associated with procuring the drill, steering module, instrumentation and service lines. The impact hammer is a self propelled drill which penetrates the soil by compacting cut material along the sidewalls of the borehole. Essentially, it forces its way through the subsurface. Although the pneumatic hammer exhausts compressed air which must be handled at the borehole collar, it does not generate soil cuttings or liquids. This is the basis for the term fluidless. A stub casing muffler was attached to the entrance hole for controlling exhaust gas and any airborne releases. Other environmental compliance modifications made to the equipment included operating the tool without lubrication, and using water instead of hydraulic fluid to actuate the steering fins on the tool

  10. How Alan Hirsig plans to play Arco chemical's strong hand

    International Nuclear Information System (INIS)

    Hunter, D.


    With 1992 net income up 4%, to $195 million. Arco Chemical (Newtown Square, PA) held its own in a year when many of its petrochemical industry peers were mauled again. Arco Chemical president and CEO Alan R. Hirsig talked recently with CW about his growth strategies for the company, and about progress with his Manufacturing Excellence initiative, lauched in the wake of the 1990 Channelview, TX tragedy. Riding on faster growth in the Asia region, Hirsig expects to see Arco's regional sales mix shift in the next three years and sales to grow from 1992's $3.1 billion to $4 billion/year. The foundation for that growth continues to be Arco's core proprietary technology competence for making propylene oxide (PO) with coproduction and tert-butyl alcohol (TBA) - the key methyl tert-butyl ether (MTBE) feedstock, or styrene monomer. Arco claims a 28% share of world MTBE capacity, its 78,500-bbl/day capacity. He cites Jakarta, Bangkok, Mexico City, Milan, Turin, and Athens as examples of major cities where MTBE use in reformulated fuels is getting interest. Given what he views as Europe's traditional 10-year lag on the US in areas like catalytic mufflers and unleaded gasoline, he sees significant prospects in reformulated gasoline in that region in the coming years. Arco is also testing a proprietary TBA-based hydroperoxide in diesel fuels, which improves the cetane number and cleans up exhaust emissions, winning great interest in Tokyo. Also in the fuels area, Hirsig notes interest in ethyl tert-butyl ether production - which Arco launched in the US in December on a commercial scale - in France

  11. Power and compression : both high-tech and low-tech combos succeed

    Energy Technology Data Exchange (ETDEWEB)

    Budd, G.


    Recently commercialized compressors were discussed. The Gas Hog is a low-horsepower compressor with a piston rod that is driven by 2 sheaves with a wrist pin. The piston has a huge 48 inch stroke which operates at only 45 revolutions per minute (RPM), which cuts down on mechanical wear and tear. There are fewer strokes per cubic foot of gas compressed, meaning that there is less waste of compression. There are currently 100 Gas Hog units in the field, as its suction/discharge profile is well suited to coalbed methane activities. The Gas Hog also has a muffler to reduce exhaust noise, and its engine compartment can be insulated. The new range of gas compressors from Brahma is designed to provide greater precision for greater energy efficiency. Varying screw speeds enhance production, allowing operators to manually adjust speeds. Scroll compressor technology has gained widespread acceptance over the last 15 years in the air conditioning and refrigeration industry, and is now being applied to oil and gas applications in vapour recovery, casing pressure modification, conventional gas and coalbed methane. The compressors can be run for a year without maintenance and can react within milliseconds to pressure change. The electric motor shaft, main bearing, counterweights and scroll are housed within a sealed unit. There are no external or internal shafts and seals to check or lubricate. There are no leaks, and no need for periodic alignment of belts. It was concluded that localized power sources will remain a key to the expanding wellhead compressor sector, due to the high cost of installing power lines for electricity. 1 fig.

  12. Validation and application of an high-order spectral difference method for flow induced noise simulation

    KAUST Repository

    Parsani, Matteo


    The main goal of this paper is to develop an efficient numerical algorithm to compute the radiated far field noise provided by an unsteady flow field from bodies in arbitrary motion. The method computes a turbulent flow field in the near fields using a high-order spectral difference method coupled with large-eddy simulation approach. The unsteady equations are solved by advancing in time using a second-order backward difference formulae scheme. The nonlinear algebraic system arising from the time discretization is solved with the nonlinear lowerupper symmetric GaussSeidel algorithm. In the second step, the method calculates the far field sound pressure based on the acoustic source information provided by the first step simulation. The method is based on the Ffowcs WilliamsHawkings approach, which provides noise contributions for monopole, dipole and quadrupole acoustic sources. This paper will focus on the validation and assessment of this hybrid approach using different test cases. The test cases used are: a laminar flow over a two-dimensional (2D) open cavity at Re = 1.5 × 10 3 and M = 0.15 and a laminar flow past a 2D square cylinder at Re = 200 and M = 0.5. In order to show the application of the numerical method in industrial cases and to assess its capability for sound field simulation, a three-dimensional turbulent flow in a muffler at Re = 4.665 × 10 4 and M = 0.05 has been chosen as a third test case. The flow results show good agreement with numerical and experimental reference solutions. Comparison of the computed noise results with those of reference solutions also shows that the numerical approach predicts noise accurately. © 2011 IMACS.

  13. On the thermodynamics of waste heat recovery from internal combustion engine exhaust gas (United States)

    Meisner, G. P.


    The ideal internal combustion (IC) engine (Otto Cycle) efficiency ηIC = 1-(1/r)(γ - 1) is only a function of engine compression ratio r =Vmax/Vmin and exhaust gas specific heat ratio γ = cP/cV. Typically r = 8, γ = 1.4, and ηIC = 56%. Unlike the Carnot Cycle where ηCarnot = 1-(TC/TH) for a heat engine operating between hot and cold heat reservoirs at TH and TC, respectively, ηIC is not a function of the exhaust gas temperature. Instead, the exhaust gas temperature depends only on the intake gas temperature (ambient), r, γ, cV, and the combustion energy. The ejected exhaust gas heat is thermally decoupled from the IC engine and conveyed via the exhaust system (manifold, pipe, muffler, etc.) to ambient, and the exhaust system is simply a heat engine that does no useful work. The maximum fraction of fuel energy that can be extracted from the exhaust gas stream as useful work is (1-ηIC) × ηCarnot = 32% for TH = 850 K (exhaust) and TC = 370 K (coolant). This waste heat can be recovered using a heat engine such as a thermoelectric generator (TEG) with ηTEG> 0 in the exhaust system. A combined IC engine and TEG system can generate net useful work from the exhaust gas waste heat with efficiency ηWH = (1-ηIC) × ηCarnot ×ηTEG , and this will increase the overall fuel efficiency of the total system. Recent improvements in TEGs yield ηTEG values approaching 15% giving a potential total waste heat conversion efficiency of ηWH = 4.6%, which translates into a fuel economy improvement approaching 5%. This work is supported by the US DOE under DE-EE0005432.

  14. Aerosols emitted in underground mine air by diesel engine fueled with biodiesel. (United States)

    Bugarski, Aleksandar D; Cauda, Emanuele G; Janisko, Samuel J; Hummer, Jon A; Patts, Larry D


    Using biodiesel in place of petroleum diesel is considered by several underground metal and nonmetal mine operators to be a viable strategy for reducing the exposure of miners to diesel particulate matter. This study was conducted in an underground experimental mine to evaluate the effects of soy methyl ester biodiesel on the concentrations and size distributions of diesel aerosols and nitric oxides in mine air. The objective was to compare the effects of neat and blended biodiesel fuels with those of ultralow sulfur petroleum diesel. The evaluation was performed using a mechanically controlled, naturally aspirated diesel engine equipped with a muffler and a diesel oxidation catalyst. The effects of biodiesel fuels on size distributions and number and total aerosol mass concentrations were found to be strongly dependent on engine operating conditions. When fueled with biodiesel fuels, the engine contributed less to elemental carbon concentrations for all engine operating modes and exhaust configurations. The substantial increases in number concentrations and fraction of organic carbon (OC) in total carbon over the baseline were observed when the engine was fueled with biodiesel fuels and operated at light-load operating conditions. Size distributions for all test conditions were found to be single modal and strongly affected by engine operating conditions, fuel type, and exhaust configuration. The peak and total number concentrations as well as median diameter decreased with an increase in the fraction of biodiesel in the fuels, particularly for high-load operating conditions. The effects of the diesel oxidation catalyst, commonly deployed to counteract the potential increase in OC emissions due to use of biodiesel, were found to vary depending upon fuel formulation and engine operating conditions. The catalyst was relatively effective in reducing aerosol number and mass concentrations, particularly at light-load conditions, but also showed the potential for an

  15. Augmented ingestion of carbon monoxide and sulfur oxides by occupants of vehicles while idling in drive-up facility lines

    Energy Technology Data Exchange (ETDEWEB)

    Myronuk, D J


    For a line-up of automobiles waiting for a period of time at a drive-up facility, the idling engine emissions are expelled in a rearward direction and tend to envelope the vehicles at the end portion of the queue. Factors that affect these highly localized pollutant accumulation episodes include local meteorological conditions, number, age and tune-up condition of the cars, exhaust pipe location, interior air handling equipment, vehicle separation distances and natural or artificial barriers that form troughs in which vehicular emissions can accumulate or be trapped. In a series of typical vehicle line-ups, local CO concentrations were measured. With Santa Clara Valley background levels of 2 to 5 ppm, the 15 min average driver-area concentration levels ranged from 15 ppm to 95 ppm with short term peaks between 100 and 1000 ppm. The exposure of humans to these concentrations of CO can result in mild headache or nausea, failure to react quickly to stimuli (like oncoming traffic) as well as setting a strain on the heart and lungs. These effects are temporary and reversible. A far more serious local air quality and health problem arises in the growing production of SO/sub x/ and sulfate compounds attributable to the legislated use of oxidizing catalytic mufflers for new car emission control and oxidation of the elemental S found in all gasoline. Using the CO levels as indicators of the accumulation of local automobile produced pollutants, when a majority of cars are equipped with catalytic converters, the anticipated adverse effects of SO/sub x/ concentrations, irritation and inflammation of healthy lung tissue of young and old people alike, as well as aggrevation of preexisting conditions of lung or heart impairment, will be a most undesirable feature of drive-up facility services. Potential reductions in the extent of this developing problem include S removal, SO/sub x/ traps and exhaust system redesign.

  16. Thirteenth workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P.; Horne, R.N.; Brigham, W.E.; Miller, F.G.; Cook, J.W. (Stanford Geothermal Program)


    PREFACE The Thirteenth Workshop on Geothermal Reservoir Engineering was held at Stanford University on January 19-21, 1988. Although 1987 continued to be difficult for the domestic geothermal industry, world-wide activities continued to expand. Two invited presentations on mature geothermal systems were a keynote of the meeting. Malcolm Grant presented a detailed review of Wairakei, New Zealand and highlighted plans for new development. G. Neri summarized experience on flow rate decline and well test analysis in Larderello, Italy. Attendance continued to be high with 128 registered participants. Eight foreign countries were represented: England, France, Iceland, Italy, New Zealand, Japan, Mexico and The Philippines. A discussion of future workshops produced a strong recommendation that the Stanford Workshop program continue for the future. There were forty-one technical presentations at the Workshop. All of these are published as papers in this Proceedings volume. Four technical papers not presented at the Workshop are also published. In addition to these forty five technical presentations or papers, the introductory address was given by Henry J. Ramey, Jr. from the Stanford Geothermal Program. The Workshop Banquet speaker was Gustavo Calderon from the Inter-American Development Bank. We thank him for sharing with the Workshop participants a description of the Bank???s operations in Costa Rica developing alternative energy resources, specifically Geothermal, to improve the country???s economic basis. His talk appears as a paper in the back of this volume. The chairmen of the technical sessions made an important contribution to the workshop. Other than Stanford faculty members they included: J. Combs, G. T. Cole, J. Counsil, A. Drenick, H. Dykstra, K. Goyal, P. Muffler, K. Pruess, and S. K. Sanyal. The Workshop was organized by the Stanford Geothermal Program faculty, staff and students. We would like to thank Marilyn King, Pat Oto, Terri Ramey, Bronwyn Jones

  17. Active control of the noise

    International Nuclear Information System (INIS)

    Rodriguez V, Luis Alfonso; Lopez Q, Jose German


    applications in areas so diverse as those that are described. In the industry: noise of fans, ducts of air, chimneys, transformers, generators, compressors, bombs, machines of washing, tunnels of wind, phone booths and others. In the transport: airplane booths, booths of helicopters, helmets for motorcycles, trains etc. in appliances: conditioners of air, ducts, cleaning machines, pruners, vacuum cleaners etc. and in the attenuation of the noise, mufflers of electronic gases in automobiles

  18. Characterizing ultrafine particles and other air pollutants in and around school buses. (United States)

    Zhu, Yifang; Zhang, Qunfang


    Increasing evidence has demonstrated toxic effects of ultrafine particles (UFP*, diameter emissions from idling school buses to air pollutant levels in and around school buses under different scenarios; 3. Retrofit tests to evaluate the performance of two retrofit systems, a diesel oxidation catalyst (DOC) muffler and a crankcase filtration system (CFS), on reducing tailpipe emissions and in-cabin air pollutant concentrations under idling and driving conditions; and 4. High efficiency particulate air (HEPA) filter air purifier tests to evaluate the effectiveness of in-cabin filtration. In total, 24 school buses were employed to cover a wide range of school buses commonly used in the United States. Real-time air quality measurements included particle number concentration (PNC), fine and UFP size distribution in the size range 7.6-289 nm, PM2.5 mass concentration, black carbon (BC) concentration, and carbon monoxide (CO) and carbon dioxide (CO2) concentrations. For in-cabin measurements, instruments were placed on a platform secured to the rear seats inside the school buses. For all other tests, a second set of instruments was deployed to simultaneously measure the ambient air pollutant levels. For tailpipe emission measurements, the exhaust was diluted and then measured by instruments identical to those used for the in-cabin measurements. The results show that when driving on roads, in-cabin PNC, fine and UFP size distribution, PM2.5, BC, and CO varied by engine age, window position, driving speed, driving route, and operating conditions. Emissions from idling school buses increased the PNC close to the tailpipe by a factor of up to 26.0. Under some circumstances, tailpipe emissions of idling school buses increased the in-cabin PNC by factors ranging from 1.2 to 5.8 in the 10-30 nm particle size range. Retrofit systems significantly reduced the tailpipe emissions of idling school buses. With both DOC and CFS installed, PNC in tailpipe emissions dropped by 20

  19. Socioeconomic and behavioural determinants of malaria among the migrants in gold mining, rubber and oil palm plantation areas in Myanmar. (United States)

    Soe, Htin Zaw; Thi, Aung; Aye, Ni Ni


    Malaria is a major public health problem in Myanmar. Migrant populations are at high risk of contracting malaria and its control is more difficult than for settled population. Studies on malaria and migration are rare in Myanmar. This study was undertaken with the main objective of identifying socioeconomic and behavioural determinants of malaria among the migrant workers involved in gold mining, rubber and oil palm plantations. A cross-sectional analytic study was conducted using pretested interview-administered questionnaires among internal migrants (n = 406) in the malaria endemic townships of Shwegyin, Bago Region, Thanbyuzayat, Mon State and Kawthaung, Taninthayi Region from August to November, 2015. Data were collected by well-trained Basic Health Staff members in study areas, and then analysed by SPSS version 16.0 using Chi-square tests with significant level at 0.05. Majority of participants were male, Bahmar nationals, married and with primary basic education level and below. The mean duration of migratory work was 4.51 years. 43.1% of them gave definite previous history of malaria within last two years during migration. 92.9% (377/406) of them always used bed nets. Malaria determinants found were male gender (OR = 1.84, 95% CI: 1.22-2.77; P = 0.0040), habit of going out at dawn (OR = 2.36, 95% CI: 1.58-3.52; P < 0.001), usual sleeping indoors (OR = 2.14, 95% CI: 1.04-4.42; P = 0.036), torn bed net or net with large hole(s) (OR = 2.0, 95% CI: 1.21-3.3; P = 0.006), habit of not always sleeping under a bed net at night (OR = 2.02, 95% CI: 1.15-3.52; P = 0.014), alcohol drinking (OR = 2.71, 95% CI: 1.73-4.26; P < 0.001) and failure to attend malaria health talk (OR = 1.78, 95% CI: 1.2-2.65; P = 0.004). The present study highlighted that it is warranted to launch an effective health education programme for malaria, and to encourage the proper use of insecticide-treated bed nets, blankets and/or mufflers and mosquito repellents to

  20. Comparison of subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers in Japan. (United States)

    Inaba, Ryoichi; Kurokawa, Junichi; Mirbod, Seyed Mohammad


    To help making comfortable workplaces and to prevent health disorders induced by the exposure to moderate cold in two different groups of out-door workers, we conducted a survey to compare subjective symptoms and cold prevention measures in winter between traffic control workers and construction workers. The subjects of this study were 98 male traffic control workers and 149 male workers engaged in building construction. Work loads of traffic control workers and construction workers were estimated at RMR1-2 and RMR2-4, respectively. All subjects were asked to complete a self-administered questionnaire covering age, occupational career, working figure, present illness, past history of diseases, individual preventive measures to the cold, subjective symptoms in the winter (43 items) and subjective symptoms occurred during daytime working in the winter (6 items). In two parts of the construction workplaces (the place where a morning assembly was held and on the 7th floor of the construction site) dry bulb, wet bulb and globe temperatures were measured in January. Windchill Index (kcal/cm,(2) x h) was calculated by the measured dry bulb temperature and wind velocity. Mean values of dry bulb temperature between 9:00 and 16:30 in the place where a morning assembly was held for three days were between 4.8 +/- 1.2 degrees C at 9:00 am and 9.3 +/- 1.1 degrees C at noon. Mean values of Windchill Index in the place where a morning assembly was held were between 490.8+/-23.9 kcal/cm(2) x h at 9:30 am and 608.2+/-47.3 kcal/cm(2) x h at 2:30 pm. Occupational career, monthly working days, daily working hours, one way commuting hours, and daily smoking numbers of the traffic control workers were significantly shorter than the construction workers (pconstruction workers (0.7%). Prevalence of wearing a warm underwear, body warmer, warm trousers, underpants, warm socks, shoe warmer and muffler in the traffic control workers were significantly higher than the construction workers. The

  1. Performance and environmental impact assessment of pulse detonation based engine systems (United States)

    Glaser, Aaron J.

    diverging ejector pressure distribution shows that the diverging section acts as a subsonic diffuser. To provide a better explanation of the observed performance trends, shadowgraph images of the detonation wave and starting vortex interacting with the ejector inlet were obtained. The acoustic signature of a pulse detonation engine was characterized in both the near-field and far-field regimes. Experimental measurements were performed in an anechoic test facility designed for jet noise testing. Both shock strength and speed were mapped as a function of radial distance and direction from the PDE exhaust plane. It was found that the PDE generated pressure field can be reasonably modeled by a theoretical point-source explosion. The effect of several exit nozzle configurations on the PDE acoustic signature was studies. These included various chevron nozzles, a perforated nozzle, and a set of proprietary noise attenuation mufflers. Experimental studies were carried out to investigate the performance of a hybrid propulsion system integrating an axial flow turbine with multiple pulse detonation combustors. The integrated system consisted of a circular array of six pulse detonation combustor (PDC) tubes exhausting through an axial flow turbine. Turbine component performance was quantified by measuring the amount of power generated by the turbine section. Direct comparisons of specific power output and turbine efficiency between a PDC-driven turbine and a turbine driven by steady-flow combustors were made. It was found that the PDC-driven turbine had comparable performance to that of a steady-burner-driven turbine across the operating map of the turbine.

  2. Third workshop on geothermal reservoir engineering: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Ramey, H.J. Jr.; Kruger, P. (eds.)


    (Lloyd's Bank of California), Stephen Lipman (Union Oil), Mark Mathisen (PG&E), Patrick Muffler (USGS-MP), and Mark Silverman (DOE-SAN); and to the rapporteurs: George Frye (Aminoil), Vasel Roberts (Electrical Power Research Institute), and Alexander Graf (LBL), whose Valuable summaries are included in the Proceedings. Special thanks are also due Roland Horne, Visiting Professor from New Zealand and Program Manager of the Stanford Geothermal Program, for his efforts with the Program graduate students in conducting the Workshop. Further thanks go to Marion Wachtel, who in spite of tremendous personal hardship, administered the Workshop and prepared the Proceedings in a timely and professional manner. Professor Ramey and I also express our appreciation to the Department of Energy, whose financial support of the Workshop made possible the program and these Proceedings. Paul Kruger Stanford University December 31, 1977

  3. Analysis of power tiller noise using diesel-biodiesel fuel blends

    Directory of Open Access Journals (Sweden)

    N Keramat Siavash


    fuel has no significant difference at 1% level with B00, B05 and B15 fuel. At the A weight level, that matches the structure of the human ear, and there is no difference between the sound pressure levels of ignition. Sound pressure level increased with increasing engine speed and the difference is significant at the 1% level. With increasing speed engine, noise levels increased up to 7.8 dB. Average sound pressure level was 83.76 dB at the driver's ear position (79.3 dBA, at 1.5 meters away from exhaust it was 85 dB (80.9 dBA and at 7.5 meters away from exhaust it was 79.5 dB (72.4 dBA. The results proved that the lowest and highest sound pressure levels (SPL of power tiller take place at B10, and B30, respectively. The SPL increased by 7.8 dB for increasing engine speed from 1200 to 2200 rpm. The test results showed that the average SPL at DLEP was 4.3 dB higher than 7.5 MAFE position. Conclusions: B10 has minimum sound pressure level (SPL, but its difference with B00 (DIESEL FUEL, B05 and B15 is not significant in 1% error level. Considering the NOISH standard, the operator can work with a machine for 8 hours. In DLPE position, the most overcome frequency is 315 Hz for all blends that resulted from exhaustion and combustion. B10 has a minimum SPL at this peak point significantly lower than other blends. For the used engine in this experiment, by optimizing muffler design it is possible to reduce SPL of engine in this frequency peak point

  4. Potentiel et limites d'utilisation, aux températures élevées, des lubrifiants liquides dans les moteurs Potential and Limitations of Use of Liquid Lubricants in Engines At High Temperatures

    Directory of Open Access Journals (Sweden)

    Toulhoat H.


    favorable. Les nouvelles formules à développer devront naturellement conserver les propriétés désirables telles que les effets anti-usure et anti-corrosion, la détergence, le pouvoir dispersant, et une bonne aptitude à l'écoulement à basse température. Les solutions techniques sont assurément à la portée de l'industrie des lubrifiants, mais au prix d'un effort de développement qui ne doit pas être sous-estimé, et cette valeur ajoutée aura dans une certaine mesure des conséquences sur les coûts. En même temps que les températures opératoires s'élèveront, de nouveaux matériaux continueront leur pénétration en tant que pièces de frottement ou barrières thermiques : les composites, les cermets, les métaux durcis superficiellement, les revêtements céramiques ou les céramiques massives. Il s'avère que les céramiques thermo-mécaniques non lubrifiées ne fonctionnent pas. D'un autre côté, les lubrifiants pourraient étendre le champ d'application des pièces de friction non métalliques en régime de lubrification limite, ou en tant que solutions à des problèmes de fatigue. On donne des exemples de formation de films interfaciaux protecteurs par réaction du DTPZn dans des conditions de frottement représentatives, avec de la zircone pure, du nitrure de silicium et de l'oxyde de chrome déposé par plasma sur de l'acier et de l'aluminium. Les coefficients de frottement se situent dans le domaine 0,03-0,1, valeurs comparables à celles des contacts métal-métal en régime de lubrification limite. This article examines the possible responses of lubricant formulations to a rise of temperatures in engines in the next decade. The increase in the specific powers of engines and the reduction of their overall dimensions and weights, the penetration of turbocompressors and catalytic mufflers, and, to some extent, a tendency to reduce heat discharges are driving forces for such a rise. An increase in the mean temperature at the oil gallery by about 15