Higher Rpm Research Articles

The effect of using the turbulence enhancement unit before the catalytic converter in diesel engine emissions

ABSTRACTThis research focuses on reducing the toxic emissions from the exhaust by installing a turbulence enhancement unit just before the three-way catalytic converter. This unit creates turbulence in the gases flowing through the combustion chamber when fitted with the Tata Indica V2 diesel engine (1405cc). Turbulence leads to the rising in the contact area of the exhaust gases going to the catalytic converter for the reactions to take place. Experimentally, it was found that swirl venturi gives the best results in the overall emission test. Although the overall best device is swirl venturi, swirl blades also give better results on higher rpm of the engine. This paper shows the detailed research on the emission test performed.

Effects of Flow on Protective Scales Formation in a CO2 Saturated Brine Environment

A significant amount of literature exists demonstrating the effect of CO2 on corrosion scale formation under non-flow conditions and its pH and temperature dependent protectivity. However, little information is available on the effects of flow on the nature and protectivity of corrosion scale. This work demonstrates the effects of flow on 4 different oil-field grade steels of varying chemistry (in terms of micro-alloying) and microstructures (ferritic /pearlitic and martensitic), in a CO2 saturated (1bar) brine (0.5 M NaCl) environment under conditions (pH = 6.3 and temperature = 80 oC) which generate a significantly compact and protective scale under non-flow conditions. Flow was introduced in the range of 0 - 3000 RPM via a rotating disk electrode (RDE) type arrangement which has been customized to comply with the needs of the experiment. The effect of flow was electrochemically characterized by potentiostatic current density (id ) vs time (t) measurement where Pt and Ag/AgCl were used as counter electrode and reference electrode respectively. Higher RPM (≥1000) indicated distinct characteristics compared to the lower RPMs (≤100) with a transition of i vs. t behavior observed around 500 RPM. Higher RPMs seemed to modulate the mechanism of the nucleation stage of scale formation and induce a relatively sluggish formation of protective scale by delaying the crystal growth process. Two plain carbon steels, J55 (ferritic /pearlitic) and L80 (Martensitic), did not show any qualitative difference in their i vs. t characteristics as function of flow. However, L80 steel required a longer time for crystal growth and achieving a similar degree of protection through scale formation compared to J55. 1 wt.% Cr micro-alloyed steels showed a lower current density compared to the plain carbon steels at the very early stage of scale formation; however the eventual protectivity of the scales formed on the plain carbon steels appeared to be much better on the basis of i vs t characteristics. Further characterizations of the scales in terms of phase identification, morphology and thickness by XRD, SEM and profilometry are in progress. Figure 1

Evaluation of ball-milling time on the physicochemical and antioxidant properties of persimmon by-products powder

Abstract Persimmon by-products are known to contain higher bioactive constituents and biological activities than several other plant by-products. The present study investigated the effect of ball-milling time on the physico-chemical and antioxidant properties of persimmon seed, peel and calyx powders. The by-products were ball-milled using a planetary ball-mill for different periods of time. Increasing ball-milling time from 12 to 24 h improved the specific surface area, solubility, and DPPH radical scavenging activities of all by-products. The variable milling time also did not have any deleterious effect on bioactive constituents, reducing power and iron chelating abilities of seed powder. Ball-milling reduced the water holding capacity of all by-products but did not affect the oil holding capacity. Based on FTIR spectroscopy, increasing milling time did not alter the major constituents of all the by-products. Thus, longer ball-milling time (24 h) at relatively higher rpm (500 rpm) has the potential to produce superfine powders with improved physicochemical and antioxidant activities, thereby adding value to various applications including food. Industrial relevance Cost effectiveness and eco friendliness are major consideration in the processing of materials. Planetary ball-mill treatment offers an alternative processing method for the utilization of fruit and vegetable industrial wastes. Owing to the nature of some materials, understanding processing time can help in the prediction and regulation of physicochemical, technological and antioxidant properties of materials.

Effect of milling speed on the quality and storage stability of maize flour

This work was undertaken to evaluate the effect of milling speed on the quality and shelf life of maize flour. Maize flour was prepared using low speed mini flour mill at 75 and 115 rpm and the results were compared with the flour prepared by commercial flour mill on the basis of recovery of flour, rise in temperature of flour, time taken, particle size distribution and changes in different quality parameters during storage. It was observed from the analysis that the recovery of flour was highest (95.26%) at 75 rpm speed although the time taken was more i.e. 27.27 minutes, but the rise in temperature during milling was very less (12.240C) as compared to commercial mill the temperature rose up to 31.120C. It was noted that the maize flour prepared at low speed was light yellow in color as compared to higher rpm which was dark yellow. The maize flour prepared at 75 rpm can be stored in low density polyethylene LDPE packaging material of (200 gauge) for two months without change in quality parameters. It was observed that the moisture content, protein content, fat content, alcoholic acidity and carbohydrates was significantly affected by storage time, packaging material and milling speed at P<0.05. Therefore, at low speed the storage stability as well as nutritional properties of the flour can be enhanced. The improved shelf life of flour can result in better marketability.

A Method for Creating Artificial Thrombi In Vitro Using a Rotating Mechanical Surface.

Thromboembolism is a common concern in ventricular assist device (VAD) therapy. Precise VAD response to pass-through thromboembolism needs to be studied in a controlled in vitro setting where specific pump parameters (i.e., power consumption, flow rates, impeller RPM) can be monitored while various types of thrombi are introduced. In this article, we describe a method for creating standardized fibrin thrombi that could be introduced into a mock circulatory loop for testing VAD response to thromboembolism. Donor equine blood collected using a sodium citrate was allowed to clot by adding calcium chloride (CaCl2) while a rotating component applied shear forces to the blood. This rotating force was applied at various speeds and at various distances into the blood. Resulting clots showed similar microscopic features to thrombi taken from explanted clinical VADs. Higher RPM of the rotating component and smaller clearances between the rotating component and the blood created clots that closely resembled ante-explant clots found within VADs in vivo. This method is an effective way to create artificial fibrin clots for use in in vitro experiments to test thromboembolism in VADs.

High cycling cadence reduces carbohydrate oxidation at given low intensity metabolic rate.

Cycling cadence (RPM)-related differences in blood lactate concentration (BLC) increase with increasing exercise intensity, whilst corresponding divergences in oxygen uptake (O2) and carbon dioxide production (CO2) decrease. Aim of the present study was to test whether a higher RPM reduces the fraction (%) of the O2 used for carbohydrate oxidation (relCHO) at a given BLC. Eight males (23.9 ± 1.6 yrs; 177 ± 3 cm; 70.3 ± 3.4 kg) performed incremental load tests at 50 and 100 RPM. BLC, O2 and CO2 were measured. At respiratory exchange ratios (RER) < 1, relCHO were calculated and the constant determining 50 % relCHO (kCHO) was approximated as a function of the BLC. At submaximal workload O2, CO2, and relCHO were lower (all p < 0.002; η2 > 0.209) at 50 than at 100 RPM. No differences were observed in O2peak (3.96 ± 0.22 vs. 4.00 ± 0.25 l · min−1) and RERpeak (1.18 ± 0.02 vs. 1.15 ± 0.02). BLC was lower (p < 0.001; η2 = 0.680) at 50 than at 100 RPM irrespective of cycling intensity. At 50 RPM, kCHO (4.2 ± 1.4 (mmol · l−1)3) was lower (p = 0.043; η2 = 0.466) than at 100 RPM (5.9 ± 1.9 (mmol · l−1)3). This difference in kCHO reflects a reduced CHO oxidation at a given BLC at 100 than at 50 RPM. At a low exercise intensity, a higher cycling cadence can substantially reduce the reliance on CHO at a given metabolic rate and/or BLC.

Ammonia and gasoline composite liquid fuel blends emulsified with ethanol and methanol for direct displacement in internal combustion engines

Ammonia, when blended with hydro carbon fuels, can be used as a composite fuel to power existing IC engines using the hydrogen energy contains in the chemical. Such blends, similar to ethanol and gasoline fuel blends can be used to commercialize ammonia as an alternative fuel. Feasibility of developing ammonia gasoline liquid fuel blends and the use of ethanol and methanol as emulsifiers to enhance the solubility of ammonia in gasoline were studied using thermostated vapor liquid equilibrium (VLE) high pressure cells, in this research. A small VLE cell was used to quantify the solubility of ammonia in gasoline more accurately and a larger VLE cell was used to develop identified fuel blends in sufficient quantities for engine dynamometer tests. A SuperFlow model 902 engine dynamometer with a GM family II Ecotec LE5 2.4L gasoline engine was used to benchmark performance of ammonia fuel blends against standard fuels. Solubility test results prove that emulsifier free pure gasoline is capable of dissolving 23 g/l of ammonia on mass basis (4.5% of ammonia on volume basis) at 50 Psi pressure and 286.65 K temperature in liquid phase. Solubility level is increased with the use of ethanol and methanol. Gasoline with 10% ethanol can retain 51.4 g/l (11.0% on volume basis) of ammonia in the liquid phase at the same pressure and temperature. Methanol has better emulsifying capabilities. Solubility level of gasoline with 10% methanol is 61.8 g/l (11.0% on volume basis). Dynamometer results show the ability of new composite fuel blends to produce the same amount of torque and power in the lower rpm limits. At higher rpm levels ammonia rich fuels result in an increased torque and power. Thus it can be concluded that hydrogen energy can be stored as ammonia-gasoline fuel blends and recovered back successfully without any strenuous modification to the existing infrastructure and end user equipment or behavior.

Volumetric resistance blower

This paper reports on a new low-noise blower rotor technology developed by Intel Corporation (patents pending). The new approach replaces the traditional centrifugal blower rotor with a block of continuous porous media. The porous media can be as simple as a low-cost, block of open-cell foam and has no blades or macroscale structure. As the porous media rotor rotates, viscous and inertial forces from the volumetric resistance of the porous media cause the air within the rotor to rotate with it, creating centrifugal forces that overwhelm the flow resistance in the radial direction and create a flow pattern similar to that achieved in a traditional blower. However, because of the lack of distinct blades, the porous-media generates nearly zero aerodynamic tonal noise and significantly reduced broadband noise. This allows the rotor to be operated at significantly higher RPM and reduced clearances relative to the traditional rotor design for further improved performance. This paper will discuss numerical modeling and experimental development of the new blower type. An iso-flow comparison of porous-media and traditional rotors with the same motor and housing demonstrate a 5 dBA reduction in broadband noise and a factor of two reduction in tonality while maintaining comparable overall efficiency. Impact of porosity and different rotor support structures are also discussed.

Within-season dynamics of red palm mite (Raoiella indica) and phytoseiid predators on two host palm species in south-west India

Field surveys were conducted monthly between December 2008 and July 2009 in Kerala, south-west India to compare the population dynamics of the red palm mite Raoiella indica (RPM) on two host plants Areca catechu and Cocos nucifera during one non-monsoon season when, in general, RPM populations increase. The aim was to examine the effects of host plant, host plant locality and the impact of climatic factors on RPM and related phytoseiid predators. There were significantly higher RPM densities on areca in peak season (May/June) compared to coconut; although significantly more coconut sites were infested with RPM than areca. Although no one climatic factor was significantly related to RPM numbers, interactions were found between temperature, humidity and rainfall and the partitioning of host plant locality showed that where conditions were warmer and drier, RPM densities were significantly higher. Specifically on coconut, there was a significant relation between RPM densities and the combined interaction between site temperature, site humidity and phytoseiid densities. There was a marked difference in the density of phytoseiids collected between areca and coconut palms, with significantly more on the latter, in several months. Amblyseius largoensis was the most commonly collected phytoseiid in association with RPM, although Amblyseius tamatavensis species group and Amblyseius largoensis species group were collected in association with RPM also. There was also evidence of a weak numerical response of the combined phytoseiid complex in relation to RPM density the previous month on coconut but this was not observed on areca.

EFFECT OF WHEAT BRAN ADDITION AND SCREW SPEED ON MICROSTRUCTURE AND TEXTURAL CHARACTERISTICS OF COMMON WHEAT PRECOOKED PASTA-LIKE PRODUCTS

The present paper describes the wheat bran addition on microstructure, texture, colour and sensory characteristics of enriched precooked pasta- -like products. Precooked pasta-like products were processed on a single screw extrusion-cooker TS-45 with L:D= 16: 1, shaped on the circular open die. Screw speed during the extrusion-cooking ranged from 60 to 120 rpm. Wheat bran were added in the amount from 5 to 25% of common wheat flour mass. The microstructure showed unmodified bran fractions at low screw speed, in turn higher rpm disrupted wheat bran cell walls. Hardness of dry pasta-like products, evaluated with the cutting test. was diminishing with a higher bran content in the recipe and was increasing with rpm applied. The firmness of hydrated products was decreasing with increasing bran addition (20 and 25% of bran in the recipe). whilst processing at low rpm caused poor quality of pasta-like products with great adhesiveness and stickiness. The higher bran content affected also the lower sensory notes. Colour measurement showed lower L * values for both raw and hydrated products with higher bran addition.

Emission of metal-oxide particles from IC-engines

All conventional piston-driven combustion engines emit metal oxide particles. The main sources are the abrasion between piston-ring and cylinder, abrasion in the bearings, catalyst coating, lube-oil additives, and fuel additives for promoting the exhaust-gas after-treatment. Metal oxides, especially from transition metals, are very toxic when they are very fine. These particles have a high BET surface and penetrate the biological system. Hence, these particles must be scrutinized for quantity, size distribution and composition. This paper draws from published data and mainly the VERT certification tests, which prescribe a size specific metal analysis. The total mass of metal oxide is 0.1 – 1 mg/km, which appears negligible. But these particles are in the 10 – 20 nm size range. Hence, this small mass represents 1015 particles per kilometer. This is approximately the same number as soot particles emitted by diesel engines. Public health should focus on the metal oxide particles that are smaller and probalby more toxic than the soot particles. SI engines run at higher RPM and therefore emit more metal oxide particles than Diesel engines. Highly efficient filtration of such particles seems therefore necessary for all engine categories

Mechanical String Thinner Reduces Crop Load at Variable Stages of Bloom Development of Peach and Nectarine Trees

Thinning of blossoms or fruitlets is a labor-intensive requirement in the production of peach and nectarine (Prunus persica) fruit of optimum size and quality. Prior research conducted by the authors on string blossom thinners for managing peach tree crop load demonstrated that this new technology reduces labor requirement and improves fruit size. The research reported in the current article was conducted over 2 years on ‘Sugar Giant’ peach and ‘Arctic Sweet’ nectarine to evaluate string blossom thinner efficacy at variable stages of bloom development ranging from pink to petal fall. Blossom removal at the pink stage of bloom development was lower than at other stages in 2008; however, a 150-rpm versus 120-rpm spindle rotation speed resulted in blossom removal similar to the 80% full bloom (FB) treatment in 2009. Blossom removal at the petal fall stage was similar to the open bloom stage with the exception of the 2009 ‘Sugar Giant’ trial, in which blossom removal was higher at 80% FB. Flower density and fruit set of the bloom stage compared with hand-thinned control treatments followed a similar trend with the exception that there were fewer differences in 2009 and in lower canopy regions. Follow-up hand thinning time was reduced by all string thinning/year combinations except ‘Arctic Sweet’ at pink in 2008 and 2009 and at petal fall in 2009. The best treatments reduced follow-up hand thinning time compared with green fruit hand thinning alone by 51% and 41% for ‘Sugar Giant’ and by 42% and 22% for ‘Arctic Sweet’ in Years 1 and 2, respectively. In 2008, the percentage of fruit in the “7.0 cm or greater” size category was increased by all bloom stage treatments in both cultivars. The 2009 size distribution of ‘Arctic Sweet’ fruit was unaffected, but the percentage of ‘Sugar Giant’ fruit in higher market value size categories was increased by the 80% FB and higher rpm pink treatments. Savings in hand thinning time and/or increases in fruit size in both years associated with the bloom stage treatments resulted in a net positive impact of $123/ha to 1368/ha compared with hand thinning alone.

Rag Layers in Oil Sand Froths

During the settling stages in some oil sands froth treatments, a rag layer (an undesirable mixture of dispersed oil, water, and solids) can form at the water−oil interface. To investigate rag layer formation, oil sand froths were diluted with mixtures of toluene and heptane and the diluted froths were centrifuged in steps of increasing rpm. The volumes of oil phase, rag layer, free water, and sediment were measured after each step. The data obtained from the experiments were used for material balances to determine the composition of the rag layers. The size and properties of the rag layer solids were also measured. Two mechanisms were found to influence rag layer formation: slow coalescence of emulsified water between 1500 and 3000 rpm (200−1000 times gravity); trapping of fine intermediate to oil wet solids at higher rpm and residence times. The main process factors affecting rag formation appear to be the type of diluent and asphaltene precipitation. As well, higher quality oil sand produced much smaller rag layers.

Utility of Suspended Solid Measurements for Storm-Water Runoff Treatment

In this paper alternative solutions are presented to solve problems associated with the measurement of total suspended solids (TSS) in storm-water runoff. Results revealed that the accuracy of TSS measurement is largely related to sample representativeness, particle size distribution (PSD), sampling pipette position, and sample mixing. In general, when the PSD in the runoff was mostly larger than 75 μm , the most accurate and reproducible results were obtained when samples were collected from a position of mid-depth and midway between the walls of the beaker and the vortex and mixed at speeds in the range of 600–700 rpm . For runoff samples with a PSD smaller than 75 μm , mixing at a higher rpm is not a significant factor. As long as the PSD in the TSS subsample is representative of the original sample, a strong correlation between TSS and suspended solid concentration can be achieved. The results showed that density was largely correlated with the organic content of the particles, and, in general, smalle...

A Study on Positioning Error Caused by Flow Induced Vibration Using Helium-Filled Hard Disk Drives

In this paper, we compare the positioning accuracy of helium- and air-filled drives. We report the PES spectra of the both drives and calculate the mechanical disturbance. The results reveal that almost all disturbances in higher rpm drives are flow induced vibrations and that disturbances in helium-filled drives are dramatically smaller. The experimental positioning error of helium-filled drives is less than half of that of air-filled drives. The static and dynamic fluid computations explaine these experimental results.

Evaluation and optimization of metal matrix composite strip produced by single roll continuous strip casting method

Metal matrix composite (MMC) strip has been made in single step through ingot metallurgy route using single roll continuous strip casting (SRCSC) technology. Composite melt of Al–Si alloy matrix and SiC particulate was prepared through vortex disperion method. Wetting characteristics of particles were improved by alloying with magnesium, preheating of particles at high temperature and stirring of composite melt. Process parameters of composite melt preparation and strip casting were optimized and composite strips were produced with different sizes of reinforcing particle and with different wt.% of particle. Particle recovery and distribution, quality of composite strip and mechanical properties at room temperature as well as at high temperature were studied w.r.t. size of particle, amount of particle added to the matrix and rotational speed of caster drum. It has been observed that size and distribution of reinforcing particle in the matrix affects the mechanical properties. Smaller size particles improve the strength and hardness of the composite. But in case of coarse particles (53–75 μm), distribution and recovery is found to be better than that of smaller size particles (<25 μm). Better distribution of particles and increase in strength was also observed at higher rpm of the caster drum. Composite strips have shown better strength at elevated temperature (<250 °C) than the matrix alloy. Improvement in ductility of composites was also noted at elevated temperature.

Comparison of Removal Times of Thermafil Plastic Obturators Using ProFile Rotary Instruments at Different Rotational Speeds in Moderately Curved Canals

The purpose of this study was to compare the time required for removal of small Thermafil plastic carriers in moderately curved MB roots of mandibular molars using the ProFile rotary system at 300 and 1,500 rpm. MB roots of 40 mandibular molars were instrumented and obturated with size 30 Thermafil plastic obturators. Teeth were divided into two groups. In group 1, sizes 55 to 25 ProFile 0.04-taper instruments were used in a crown-down manner at 300 rpm. In group 2, size 25 ProFile 0.04-taper instruments were used at 1,500 rpm. Time of carrier removal and the number of instrument separations were recorded. The Student’s t test demonstrated a significant difference between groups: 4 minutes 12 seconds for group 1 and 1 minute 28 seconds for group 2 (p < 0.001). However, a trend for greater separation of instruments was found with the higher rpm group.

Factorial analysis of diesel engine performance using different types of biofuels

In this study, several bio-source-fuels like fresh and waste vegetable oil and waste animal fat were tested at different injector pressures (120, 140, 190, 210 bar) in a direct-injection, naturally aspirated, single-cylinder diesel engine with a design injection pressure of 190 bar. Using 2 k factorial analysis, the effect of injection pressure ( P i) and fuel type on three engine parameters, namely, combustion efficiency ( η c), mass fuel consumption ( m f), and engine speed ( N) was examined. It was found that P i and fuel type significantly affected both η c and m f while they had a slight effect on engine speed. Moreover, with diesel and biodiesels, the η c increased to a maximum at 190 bar but declined at the higher P i value. In contrast, higher P i had a favorable effect on η c over the whole P i range with all the other more viscous fuels tested. In addition, the mass fuel consumption consistently decreased with an increase in P i for all the fuels including the baseline diesel fuel, with which the engine consistently attained higher η c and higher rpm compared to all the other fuels tested.

The performance impact of I/O optimizations and disk improvements

In this paper, we use real server and personal computer workloads to systematically analyze the true performance impact of various I/O optimization techniques, including read caching, sequential prefetching, opportunistic prefetching, write buffering, request scheduling, striping, and short-stroking. We also break down disk technology improvement into four basic effects—faster seeks, higher RPM, linear density improvement, and increase in track density—and analyze each separately to determine its actual benefit. In addition, we examine the historical rates of improvement and use the trends to project the effect of disk technology scaling. As part of this study, we develop a methodology for replaying real workloads that more accurately models I/O arrivals and that allows the I/O rate to be more realistically scaled than previously. We find that optimization techniques that reduce the number of physical I/Os are generally more effective than those that improve the efficiency in performing the I/Os. Sequential prefetching and write buffering are particularly effective, reducing the average read and write response time by about 50% and 90%, respectively. Our results suggest that a reliable method for improving performance is to use larger caches up to and even beyond 1% of the storage used. For a given workload, our analysis shows that disk technology improvement at the historical rate increases performance by about 8% per year if the disk occupancy rate is kept constant, and by about 15% per year if the same number of disks are used. We discover that the actual average seek time and rotational latency are, respectively, only about 35% and 60% of the specified values. We also observe that the disk head positioning time far dominates the data transfer time, suggesting that to effectively utilize the available disk bandwidth, data should be reorganized such that accesses become more sequential.

Phosphate glasses for tissue engineering: Part 2. Processing and characterisation of a ternary-based P 2O 5–CaO–Na 2O glass fibre system

This paper presents the results of a study of the thermal properties, solubility and dimensions of a range of phosphate-based glass fibres (PB-GFs). The glass compositions were limited by fixing the P 2O 5 content to 45, 50 and 55 mol%, and varying the CaO mol% at 30, 35 and 40. PB-GFs were obtained from the 50 and 55 mol% P 2O 5 compositions; however, we were unable to obtain fibres from the 45 mol% compositions. This was linked to the cross-linked density, network connectivity and average chain length of the compositions studied. With regards to thermal parameters investigated, initial data showed an increase of the T g and crystallisation temperatures with increasing CaO mol% at each fixed phosphate content. A decrease in T g temperatures was also observed with increasing P 2O 5 content to 55 mol%. The crystallisation temperatures obtained for compositions with fixed phosphate at 55 mol%, showed a reverse pattern, with a decrease in values as compared to the fixed 50 mol% phosphate compositions. The diameters of the fibres all decreased with increasing RPMs as expected, and the solubility also increased with increasing RPMs. This was related to the increased surface area of the higher RPM fibres. There was also a decrease seen in solubility with increasing CaO mol%.