Manifold System Research Articles

PERFORATED MUFFLER MANIFOLD CATALYST

An alternative exhaust manifold system, the Perforated Manifold, Muffler, and Catalyst (PMMC), is proposed to improve sound suppression while reducing engine pumping losses and exhaust emissions. One-dimensional predictions from acoustic theory are used to configure the initial design. Preliminary evaluation of the concept is based on bench tests, including an extended impedance tube set-up for acoustic attenuation and a flow bench for flow loss characteristics. Experiments with the fabricated hardware are then conducted in an engine dynamometer facility, and the results were compared to the existing production system as a benchmark. Engine experiments show that the PMMC concept provides enhanced upstream sound suppression, reducing the need for restrictive downstream silencers. This results in reduced engine pumping work and thus improved engine break horsepower. Additionally, conservation of exhaust gas thermal energy and the reduced thermal inertia of the exhaust system provides earlier catalyst light-off, and therefore reduced pollutant emissions.

Influence of the Exhaust System on Performance of a 4-Cylinder Supercharged Engine

Twin entry radial turbines are mostly used to drive compressors of small and medium size 6-cylinder diesel engines where the available energy of the undisturbed exhaust pulses can be efficiently used to drive the turbine of a turbocharger. Three selected cylinders feed two separated manifold branches and two turbine inlets and prevent negative interaction of pressure waves and its influence on the scavenging process of the individual cylinders. In the case of a four-stroke, 4-cylinder engine, two selected cylinders, directed by the firing order, can be connected to one (of the two) separated manifold branches that feeds one turbine entry. Good utilization of the pressure pulse energy, together with typically longer periods of reduced exhaust flow can lead to good overall efficiency of the “two-pulse” system. Sometimes this system can be superior to the single manifold system with four cylinders connected to one singleentry turbine. The paper describes advantages and disadvantages of the above described exhaust systems applied to a turbocharged and aftercooled 4-cylinder Diesel engine. Comparisons supported by the analyses of the numerical and experimental results are also given in the presented paper.

On the Nonemptiness of the Adjoint Linear System of Polarized Manifolds

AbstractLet (X, L) be a polarized manifold over the complex number field with dim X = n. In this paper, we consider a conjecture of M. C. Beltrametti and A. J. Sommese and we obtain that this conjecture is true if n = 3 and h0(L) ≥ 2, or dim Bs |L| ≤ 0 for any n ≥ 3. Moreover we can generalize the result of Sommese.

Investigation of interference effects for a group of finite cylinders

Abstract An experimental study of the interference effects between two and three cylinders of finite height immersed in a turbulent boundary layer at subcritical Reynolds numbers has been conducted in a boundary layer wind tunnel, utilizing a pneumatic averaging manifold system to measure the fluctuating force at various levels. Measurements of mean drag and lift force coefficients, mode-generalized RMS drag and lift force coefficients, and mode-generalized drag and lift force spectra, for a range of cylinder spacings, configurations, and various angles of attack, are presented. The interference levels observed were found to depend strongly on the spacing, angle of attack, and the arrangement of the cylinders with respect to each other. The investigation of these relationships for finite cylinders should prove insightful to those interested in such phenomena.

Troika Subsea Production-Template and -Manifold System

This article is a synopsis of paper OTC 8847, "Troika Subsea Production-Template and -Manifold System," by T.L McInturff, Manatee Inc., originally presented at the 1998 Offshore Technology Conference, Houston, 4-7 May.

Evaluation of the Performance of DNPH-Coated Silica Gel and C18 Cartridges in the Measurement of Formaldehyde in the Presence and Absence of Ozone

Formaldehyde (HCHO) is an important photochemical product generated during the oxidation of volatile organic compounds in the troposphere. Accurate HCHO concentrations are essential for developing a quantitative basis for ozone formation and represent a primary monitoring objective for the Photochemical Assessment and Monitoring Stations (PAMS). In the PAMS network, measurements of HCHO are conducted by a derivatization method using cartridges coated with 2,4-dinitrophenylhydrazine (DNPH). In this study, a manifold system has been designed to evaluate the performance, accuracy, and importance of interfer ences of DNPH-coated silica gel and C18 cartridges using gas-phase calibration standards. Compared to the independent gas-phase calibration values, HCHO values from silica gel cartridges were typically 5% lower than the reference values over the range of 2−25 ppbv; C18 cartridge values were systematically lower by 20%. These results were found to be independent of the level of humidity in the system. The ...

On-line sorption preconcentration of chromium(VI) and its determination by flame atomic absorption spectrometry

A method was developed for the determination of Cr(VI) by flame atomic absorption spectrometry (FAAS) after on-line sorption preconcentration. The solution containing Cr(VI) was reacted with ammonium-pyrrolidinedithiocarbamate (APDC) in a flow injection manifold system designed for this purpose and the non-water soluble chromium complex formed was adsorbed in a sorption reactor. The commercial PEEK (polyether ether ketone) loop used in liquid chromatography (LC) was introduced instead of a knotted reactor recommended for preconcentration of other trace elements in the literature. The Cr-PDC complex was retained by the PEEK loop, from which the chromium complex could be eluted rapidly by methyl isobutyl ketone into the flame. The PEEK loop is cheaper than the LC column used previously for preconcentration of Cr(VI), it can easily be inserted into the system and it is practically of unlimited lifetime. The preconcentration could also be done at much greater flow rates than that for columns because of the little hydrodynamic resistance of the loops. Thus the duration of the determination could considerably be reduced. The preconcentration of 5 ml of Cr(VI) sample and FAAS determination could be carried out within 2 min. The enrichment factor was 65. The detection limit (3 σ) was 2.0 ng ml −1. The relative standard deviation was 2.1% for 50 ng ml −1 and 6.8% for 5 ng ml −1 Cr(VI) ( N=5). The proposed method was applied for determination of Cr(VI) in various water and cigarette ash samples.

On-line dilution with sequential injection analysis: a system for monitoring sulphate in industrial effluents

On-line dilution with sequential injection analysis has been evaluated for sulphate monitoring in industrial effluents using a dilution coil in the conduits of the manifold system and a dilution step as part of the timing sequence. The manifold of the SIA system with the dilution coil is more complex than the system including the dilution step. The former method needs more complicated programming as well. Shorter analysis time favoured the dilution with the dilution step, but the limited linear range of this method is a large drawback. The large linear range of the SIA system with dilution coil makes it very suitable to be used as a process analyser. The proposed SIA system is suitable to monitor sulphate in industrial effluents in the range 50–5000 mg/L with a dilution coil, in the range 50–1000 mg/L with a timing sequence of 6.5 s and in the range 750–5000 mg/L with a timing sequence of 15 s using a dilution step; all three ranges with a RSD <4.5%.

Non-holonomic Lagrangian systems in jet manifolds

A geometrical setting in terms of jet manifolds is developed for time-dependent non-holonomic Lagrangian systems. An almost product structure on the evolution space is constructed in such a way that the constrained dynamics is obtained by projection of the free dynamics. A constrained Poincare - Cartan 2-form is defined. If the non-holonomic system is singular, a constraint algorithm is constructed. Special attention is devoted to Caplygin systems and a reduction theorem is proved.

Analytical Chemistry in Medical Science and Technology. Flow-injection spectrophotometric determination of albumin in spinal fluid with 5,10,15,20-tetrakis (4-sulfonatophenyl) porphine.

5, 10, 15, 20-tetrakis(4-sulfonatophenyl)porphine (TPPS), a water-soluble porphyrin as an ultra-high-sensitive chromogenic reagent, was used for the determination of small amounts of albumin. In the association reaction of TPPS and albumin under a weak acidic condition (pH 3.0), their aggregates were quantitatively formed within one minute at room temperature, and the absorption spectra in the Soret band changed from the absorption maxima of TPPS (434 nm, ε=5.0× 105 M-1 cm-1) to that of an aggregate (420 nm, ε= 2.8 × 105 M-1 cm-1) along with an increase in the albumin concentration. Based. on these results, a spectrophotometric detection-FIA system was developed. The proposed FIA is a double-line manifold system: A line for an acetic acid-sodium chloride solution (0.05 M), and B line for a TPPS solution (5 ×10-7M). The mixing coil uses a 1 mmφ × 1 m teflon tube. The liquid flow rate is 2.0 ml/min and the detection wavelength is 434 nm. A one hundred μl sample solution was injected into the FIA. The calibration curve gave a straight line over the concentration range of [albumin]T=0 20 μg/ml, and the detection limit (S/N=3) was 0.15 μg/ml. At least one hundred and twenty samples could be determined within one hour {the RSD: 1.51 %, 5 determinations for [albumin]T=10 μg/ml}. On the other hand, although the coexistence of γ-globulin seriously interfered with the determination of albumin, this influence was removed by the addition of sodium chloride ([NaCl]T=0.05 M). This method was applied to a dog's spinal fluid sample with satisfactory results.

Design and analysis of a high heat load pin-post monochromator crystal with an integral water manifold (abstract)

Conventional minichannel water cooling geometry will not perform satisfactorily for x-radiation from a wiggler source at the Advanced Photon Source. For closed-gap wiggler operation, cryogenic silicon appears to be the only option for crystals in Bragg-Bragg geometry. For operation of the wiggler at more modest critical energies (&amp;lt;17 keV), the first crystal can be cooled by a pin-post cooling scheme, using water at room temperature as a coolant. In order to limit the water consumption to 4 gpm and hence the risk of introducing vibrations to the crystal, the intensely cooled area of the crystal was matched to the footprint of the beam, leaving a less cooled area of the crystal subject to survival in a missteered beam but not to perform as a monochromator. The manifold design avoids large areas of high water pressure that would bow the crystal. We present here the design of a pin-post monochromator consisting of a four-layer silicon manifold system and an integrally bonded 39% nickel-iron alloy base plate. A transparent prototype of the design will be exhibited. Fabrication techniques and design advantages will be discussed.

Design of a Multi‐Level Monitoring Well for Continuous Sample Collection

AbstractAs part of a study of the flow dynamics and sampling environment around a high‐capacity irrigation well, it was necessary to design and install a multi‐level monitoring well network close to the production well. A requirement of the monitoring well network was the capability of continuous pumping over periods typical of those used during water sample collection. This was accomplished through the use of a control valve and air manifold system connected 10 a common gasoline engine‐operated air compressor. The system provided adequate air pressure to operate 24 half‐size bladder pumps to depths between 21 feet (6.4 m) and 56 feet (17.1 m) below the surface. Preliminary data collected from the monitoring well network indicate that the system will meet the requirements of the high‐capacity well study.

Fluid dynamic study of fuel cell devices: simulation and experimental validation

The paper is concerned with the mass flow distribution in fuel cell stacks. In particular, the flow through the manifold system connected to the parallel arrangement of the cell channels is modelled and numerically treated. The numerical results are recognized to be more realistic than those obtained by means of an approximate analytical solution since more detailed effects could be accounted for. This evidence is confirmed by experiments carried out at a stack model device consisting of 100 cells. Pressure and velocity distributions were measured for various Reynolds numbers and geometrical shapes of the manifolds. The agreement between the experimental and numerical results is good.

Use of Saccharomyces cerevisiae in flow injection atomic absorption spectrometry for trace metal preconcentration.

The yeast Saccharomyces cerevisiae was covalently immobilized on controlled pore glass (CPG) using a modified method of enzyme immobilization. This species was packed in a mini-column and incorporated in a flow injection manifold system for trace determination of some metals prior to quantification with atomic absorption spectrometry (AAS). A number of investigations on the ability of the microorganism to remove metal ions from solution have shown that different metal ions bind to the cell wall of yeast. We have observed that the pH-dependence behavior is different for Pb(II) and Fe(III) compared to the other metal ions. Between pH 6.0 and 7.5 a variety of metal ions bind strongly to the cell surface. All the metal ions tested were deabsorbed by lowering the pH to < 2.0. Samples of 5 mL of Cd(II), Zn(II), Cu(II), Pb(II), and Fe(III) were preconcentrated to give detection limits of 0.2, 0.1, 0.7, 8.0, and 0.6 ng/mL, respectively. The analysis of real sample reference material showed a good agreement with the certified values for cadmium and copper.

Communications: Comparison of Two Methods of Oxygen Supplementation for Enhancing Water Quality in Fish Culture

Abstract In this study, we compared sealed column oxygen supplementation with a pipeline oxygenation system at gas-to-liquid flow ratios of 0.7, 1.5, and 2.2%. The sealed columns receiving oxygen at a gas-to-liquid ratio of 2.2% increased dissolved oxygen by 73.5% (to 149.3% oxygen saturation) while decreasing nitrogen saturation and total dissolved gas saturation to 93.1 and 105.0%, respectively. Oxygen added at a gas-to-liquid ratio of 2.2% through the pipeline manifold increased raceway dissolved oxygen by 53.7% (to 134.6% oxygen saturation) and reduced nitrogen and total dissolved gas saturations to 99.0 and 106.1%, respectively. Sealed column oxygen supplementation was most efficient, having an oxygen transfer efficiency of 82.3% when a 0.7% gasto-liquid ratio was used. Oxygen added through the pipeline manifold resulted in a 54.1–62.7% variation from mean column effluent dissolved oxygen. The pipeline manifold also caused column water flow fluctuations that varied by as much as 21%. We recommend oxygen injection directly into sealed columns over use of a pipeline manifold system for adding supplemental oxygen to fish-rearing water.

High‐precision measurements of mercury vapor in air: Design of a six‐port‐manifold mass flow controller system and evaluation of mass flow errors at atmospheric pressure

We constructed an atmospheric sampling system for Hg vapor that utilizes a single vacuum pump connected via a manifold to six separate mass flow controllers (MFC). The manifold system reduces the size and power requirements for collection of replicate samples, is ideally suited for use on meteorological towers, and achieves the precise control of air‐sampling volumes required for computing air/surface exchange rates from concentration gradients of Hg vapor. In testing our air sampling systems, we found consistent calibration errors between the manufacturer's calibrations and a standard bubble flow meter. Errors as high as 30% decreased systematically with increasing flow rate to values of 3–5% at near‐maximum flow. The relative error patterns established between adjacent MFC units in each system were found to be relatively stable over time. Using gold‐coated sand amalgamation traps for Hg vapor and the flow correction factors computed from our calibrations, we routinely achieve precision for replicate measurements of Hg vapor in background air of 0.5–2% (expressed as relative standard errors of mean concentrations of 1.5–3.5 ng/m3). Application of the flow correction factors measurably decreases the level of bias between mean concentrations of Hg vapor measured with adjacent sampling systems and is necessary to reduce uncertainty associated with quantifying gradients in atmospheric concentrations.

An intercomparison of two chamber methods for the determination of emission of nitric oxide from soil

Abstract Two chamber-based methods for measurement of emission of NO from soil have been compared. One method measured NO by conversion to NO2 with a CrO3 converter and NO2 detection by luminol chemiluminescence. The other technique detects NO directly via NO/ozone chemiluminescence. The techniques were tested with a glass manifold system by addition of NO and other trace gases into a flowing zero air gas stream; water vapor was also added to the carrier gas in some cases. A second set of tests involved the simultaneous determination of NO concentrations from a chamber placed over the soil. Finally, flux measurements were made independently from common plots and from different plots within the same field. The luminol system was unaffected by the presence of ammonia, methylamine, acetonitrile and nitrous oxide, but had a lower response to NO in the presence of water vapor. The decrease was 7% at a relative humidity of 50%, and about 3% at a relative humidity of 23%. The NO/ozone chemiluminescence system was not influenced by any of the species doped into the gas stream. The simultaneous chamber data also showed a decreased response from the luminol system that was consistent with the humidity effect observed in the manifold tests. The average of independently measured flux values from common plots agreed reasonably well. However, the overall site mean flux determined by the luminol system was 74% of that of the NO/ozone system due to a larger data set from the luminol system. This comparison demonstrates that flux spatial heterogeneity can overwhelm analytical uncertainties, and that large sample sizes are needed to accurately characterize field fluxes.

Discussion of “Calculating Flow in Manifold and Orifice System” by Fazal H. Chaudhry and Luisa F. R. Reis (July/August, 1992, Vol. 118, No. 4)

Discussion of “Calculating Flow in Manifold and Orifice System” by Fazal H. Chaudhry and Luisa F. R. Reis (July/August, 1992, Vol. 118, No. 4)

Closure to “Calculating Flow in Manifold and Orifice System” by Fazal H. Chaudhry and Luisa F. R. Reis (July/August, 1992, Vol. 118, No. 4)

Closure to “Calculating Flow in Manifold and Orifice System” by Fazal H. Chaudhry and Luisa F. R. Reis (July/August, 1992, Vol. 118, No. 4)

The effect of transition to turbulent flow in tubing networks for fluctuating pressure measurement

The transfer function of multitube manifold systems used for dynamic pressure measurements has been analyzed with special attention to the effect of transition to turbulence. The theory of Gumley [2] is used to compute the transfer function of the system. This theory is based on laminar flow, and it is therefore important that the flow stays laminar and no transition occur. Using a transition criterion which depends on both the frequency and the magnitude of the velocities induced in the different tubes, it is shown that if turbulent flow is to be avoided, this may put severe restrictions on the amplitude that may be allowed in the pressure to be measured. It is also shown that the limitations in the amplitude depends strongly on the geometrical layout of the system. The limitations imposed by turbulent free flow in the tubes may explain the differences observed between the calculations and measurements.