Effect Of Tube Length Research Articles

Aberration compensation for optical trapping of cells within living mice.

Optical tweezers have been used to trap and manipulate microparticles within living animals. When the optical trap is constructed with an oil-immersion objective, it suffers from spherical aberration. There have been many investigations on the influence of spherical aberration when the particles are trapped in a water medium. However, the dependence of optical force on trapping depth is still ambiguous when the trapped particles are immersed in a high refractive index medium (such as biological tissue, refractive index solution) in experiments. In this paper, the microparticles are immersed in an aqueous solution of glycerol to mimic the cells within biological tissue. As the trapping laser is focused into the specimen, spherical aberration is introduced, degrading the optical trapping performance. It is similar to trapping in water; altering the effective tube length can also compensate for the spherical aberration of the optical trap in a high refractive index medium. Finally, the cells in living mice are trapped by the optical tweezers with the help of spherical aberration compensation.

Investigation of crack propagation path in tube gears

In this paper, the crack propagation behaviour in tube gears has been investigated. This kind of gear find application in aerospace and in particular in helicopter drivelines. For this reason, an accurate design against catastrophic failure due to particular crack propagation paths, has to be performed. In this work, the effect of tube length and rim thickness and also speed on crack propagation path has been analysed by means of extended finite elements models. In particular, to better understand the effect of speed, the changes in stress intensity factors KI and KII have been considered. Particular crack propagation shapes (wave propagation) have been found in some cases where the length ratio is particularly high.

水および炭化水素系作動媒体による小型焼却炉の排熱回収および熱動力変換量の数値予測

The heat transfer between exhaust gas and working fluid in a series of helical tube installed in a combustion furnace was analyzed numerically in order to discuss the development of heat recovery system combined with a small size combustion furnace. The dimensions of the equipment were about 0.49 m3 volume chamber with 2.5 m height chimney where the 250 m helical tube piping was available. The assumption of uniform gas side temperature referenced by the CFD simulation was used for simplify of the gas-side analysis. The inside heat transfer rate with phase change of working fluids were estimated numerically. The amounts of generation vapor and the effective tube length of pressure drop and the isentropic theoretical thermal efficiency on T-s diagram for water and hydrocarbons were also analyze for the discussion in comparison.

E-beam irradiation effects on IR absorption bands in single-walled carbon nanotubes

Abstract We have measured the absorption and Raman spectral change induced by the irradiation of e-beam. By the irradiation of e-beam on SWNTs thin films, the intensity of defect related Raman band increase, and the peak energy of IR absorption bands shift to the higher energy side. These results indicate that the origin of infrared band is due to the plasmon resonance of finite-length SWNT. We have estimated the effective tube length and defect density from IR absorption peak energy.

Design of an outdoor stacked – tubular reactor for biological hydrogen production

Photofermentation is one alternative to produce hydrogen sustainably. The photobioreactor design is of crucial importance for an economically feasible operation, and an optimal design should provide uniform velocity and light distribution, low pressure drop, low gas permeability and efficient gas–liquid separation. A glass, stacked tubular bioreactor aimed at satisfying these criteria has been designed for outdoor photofermentative hydrogen production by purple non sulfur bacteria. The design consists of 4 stacked U-tubes (tube diameter 3 cm) and 2 vertical manifolds. The hydrodynamics of the 3-dimensional model of this reactor was solved via COMSOL Multiphysics 4.1. The effects of tube length (1.4, 2.0, 3.8 m), tube pitch (8, 10.5, 13 cm) and volumetric flow rate (25–250 L/h) on the flow distribution were investigated. The glass stacked tubular reactor design results in less ground area and longer life time. This design has been constructed and operated with using Rhodobacter capsulatus YO3 hup− and molasses as the carbon source under outdoor conditions.

気体圧力変動を用いた気泡発生制御法における導管長さ及び境界条件の影響

気体圧力変動を用いた気泡発生制御法における導管長さ及び境界条件の影響

Dew Point Measurement Error due to Tube Length in a Calibration Instrumentation and the Evaluation of Measurement Uncertainty

The purpose of this paper is to analyze the effect of tube length in calibration instrumentation on dew point measurement of dew point sensors (DPS) and evaluation of measurement uncertainty. When measuring dew point temperature, various tube lengths between dew point generator and dew point sensor (DPS) cause a significant error due to moisture absorption of inner tube. The measurement is carried out to analyze the variation on measured dew point temperature for four cases of tube lengths with 300 mm, 1200 mm, 2500 mm and 5000 mm. The dew point temperature measurements were performed in the range from-60 °C to 10 °C by using calibrated standard chilled mirror hygrometer as reference standard. In order to investigate contribution to the standard uncertainty for the tube length variation as an uncertainty source, expanded uncertainties were evaluated for the cases including the effect of tube length variation as an uncertainty source and excluding it at each measurement point. The measurement was conducted according to standard calibration procedure of Korea Testing Laboratory which assures suitability and traceable results. It is also based on international standards.

Estimation of stature from maxillo-facial anthropometry in Tripuri population

Barium sulfate deposition on the inner surface of a tube is one of the most serious oil field problems affecting oil field water injection systems. The effects of tube length, liquid volume, deposition time, the profile of the Ba2+ concentration in the outlet and the pressure drop in the tubing were evaluated using a graphite furnace atomic absorption spectrometer (GFAAS) and pressure transducer methods. The deposition model of BaSO4 in the tube is presented using coupled mass balance and fluid flow equations. The deposition model contains two governing parameters, the kinetic coefficient and the deposition coefficient, which can be estimated from experimental data. The predictions from the simplified model for barium sulfate scale were in good agreement with experimental data and laboratory observations. In addition, it was proved that many factors are important for deposition kinetics, including the accumulated barium ion amount, the initial flow rate, the initial barium concentration and the deposition time. Scanning electron microscopy (SEM) images of the inlet and outlet of the tube reveal the deposition thickness and morphology.

Experimental investigation on heat transfer coefficient during upward flow condensation of R410A in vertical smooth tubes

This paper presents an experimental investigation on condensation of R410A upward flow in vertical tubes with the same inner diameter of 8.02mm and different lengths of 300 mm, 400 mm, 500 mm and 600mm. Condensation experiments were performed at mass fluxes of 103–490 kg m−2s−1. The saturation temperatures of experimental condition were 31°C, 38°C and 48°C, alternatively. The average vapor quality in the test section is between 0.91 and 0.98. The effects of tube length, mass flux and condensation temperature on condensation were discussed. Four correlations used for the upward flow condensation were compared with the experimental data obtained from various experimental conditions. A modified correlation was proposed within a ±15% deviation range.

Effect of aspect ratio on the uptake and toxicity of hydroxylated-multi walled carbon nanotubes in the nematode, Caenorhabditis elegans.

ObjectivesIn this study, the effect of tube length and outer diameter (OD) size of hydroxylated-multi walled carbon nanotubes (OH-MWCNTs) on their uptake and toxicity was investigated in the nematode Caenorhabditis elegans using a functional mutant analysis.MethodsThe physicochemical properties of three different OH-MWCNTs were characterized. Uptake and toxicity were subsequently investigated on C. elegans exposed to MWCNTs with different ODs and tube lengths.ResultsThe results of mutant analysis suggest that ingestion is the main route of MWCNTs uptake. We found that OH-MWCNTs with smaller ODs were more toxic than those with larger ODs, and OH-MWCNTs with shorter tube lengths were more toxic than longer counterparts to C. elegans.ConclusionsOverall the results suggest the aspect ratio affects the toxicity of MWCNTs in C. elegans. Further thorough study on the relationship between physicochemical properties and toxicity needs to be conducted for more comprehensive understanding of the uptake and toxicity of MWCNTs.

Experimental Investigation of Flame Propagation in Long, Narrow, and Open Tubes

AbstractAn experimental investigation of premixed propane-air flames propagating in long, narrow tubes open at both ends was performed in order to establish flame phenomenology and make comparisons to theoretical predictions. Fuel-air equivalence ratios of 0.8, 1.0, 1.2, and 1.4 were studied, and the effect of tube length was investigated using lengths of 59.1 and 104 cm. Quantitative comparisons to theoretical studies provided support to the hypothesis that a pressure gradient is established in the tube because of the Poiseuille flow induced in the gas by the flame, leading to flow away from the flame in both directions. Several regimes of propagation were established, including initial smooth propagation at constant speed, regions of high-amplitude oscillation accompanied by flame acceleration, and regions of small-amplitude oscillation during which the mean propagation speed was nearly uniform. The most intense flame oscillations and consequent acceleration occurred in mixtures with equivalence ratios ...

Curvature-relevant analysis of eccentrically loaded circular concrete-filled steel tube columns

The existence of curvature can reduce the effective confining pressure within concrete-filled steel tube (CFST) columns under eccentric compression. The existing analysis method ignores such an effect and still treats the confining pressure as constant across the whole section as if it is under axial compression. In this paper, the authors have made significant improvements on the existing model, so that the curvature effect can be taken into account to properly interpret the non-linear behaviour of eccentrically loaded CFST columns. Meanwhile, shortening between two hinges is an important data output in test programmes of this type, which has been completely neglected by the existing analysis method. This improved method also provides calculation steps to track the value of shortening for each load increment. Unknown parameters in this new method are determined on the basis of data fitting of 87 specimens from previous researchers' test programmes. The following parameters are incorporated in this study: effective tube length (660–4670 mm), diameter of tube (76–600 mm), tube thickness (1·52–8·81 mm), yield strength of tube (256·4–517·0 MPa), cylinder strength of concrete (26·42–112·70 MPa) and eccentricity (9·4–300 mm). The load–axial displacement, load–deflection and moment–curvature curves predicted by the new method agree well with their measured counterparts in the tests.

An experimental and modeling study of barite deposition in one-dimensional tubes

Barium sulfate deposition on the inner surface of a tube is one of the most serious oil field problems affecting oil field water injection systems. The effects of tube length, liquid volume, deposition time, the profile of the Ba2+ concentration in the outlet and the pressure drop in the tubing were evaluated using a graphite furnace atomic absorption spectrometer (GFAAS) and pressure transducer methods. The deposition model of BaSO4 in the tube is presented using coupled mass balance and fluid flow equations. The deposition model contains two governing parameters, the kinetic coefficient and the deposition coefficient, which can be estimated from experimental data. The predictions from the simplified model for barium sulfate scale were in good agreement with experimental data and laboratory observations. In addition, it was proved that many factors are important for deposition kinetics, including the accumulated barium ion amount, the initial flow rate, the initial barium concentration and the deposition time. Scanning electron microscopy (SEM) images of the inlet and outlet of the tube reveal the deposition thickness and morphology.

Improved performance of secondary heat exchanger for latent heat recovery from flue gas using mini-tubes

A new type of heat exchanger, in which flue gas flows inside thin tubes and cool water is on the shell-side, was proposed to develop the performance and compactness of shell and tube type heat exchangers for latent heat recovery from flue gas. The experimental heat transfer characteristics of single tubes were systematically investigated to determine the effects of tube diameter (1.0–5.0 mm) and length (7–100 mm). Furthermore, a correlation between the non-dimensional bulk mean temperature and the ratio of effective tube length to the thermal entrance region was proposed and was correlated well with the measurement data. Prediction of the heat exchanger performance using this correlation was possible. As a result, it was elucidated that the using mini-tubes is remarkably effective to reduce the size of heat exchanger due to enhancement of heat transfer coefficient and enlargement of heat transfer surface. The volume with 1 mm inner diameter of tubes was approximately 5 percent of that with 5 mm in diameter.

Chirality dependent elastic properties of single-walled boron nitride nanotubes under uniaxial and torsional loading

The elastic behavior of single-walled boron nitride nanotubes is studied under axial and torsional loading. Molecular dynamics simulation is carried out with a tersoff potential for modeling the interatomic interactions. Different chiral configurations with similar diameter are considered to study the effect of chirality on the elastic and shear moduli. Furthermore, the effects of tube length on elastic modulus are also studied by considering different aspects ratios. It is observed that both elastic and shear moduli depend upon the chirality of a nanotube. For aspect ratios less than 15, the elastic modulus reduces monotonically with an increase in the chiral angle. For chiral nanotubes, the torsional response shows a dependence on the direction of loading. The difference between the shear moduli against and along the chiral twist directions is maximum for chiral angle of 15°, and zero for zigzag (0°) and armchair (30°) configurations.

Effect of advanced surfaces on the ammonia absorption process with NH3/LiNO3 in a tubular bubble absorber

An experimental study was conducted to investigate the effect of advanced surfaces on the ammonia absorption process in tubular bubble absorbers using NH3/LiNO3 as a working pair at operating conditions of interest for absorption chillers. The tubular bubble absorber is a vertical double-pipe heat exchanger in which absorption takes place in the inner tube. In order to compare the effect of surface enhancement, a smooth tube and an internally micro-finned tube were tested. The inner tube of the absorber is made of aluminium and has an outer diameter of 8.0mm and the micro-finned tube has internal helical micro-fins measuring 0.3mm in length. The effect of tube length on absorption was also studied using two tube lengths (1 and 3m) and two tube diameters (8 and 9.5mm).Our results show that the absorption rate achieved with the micro-finned tube is up to 1.7 times higher than with the smooth tube at a solution mass flow rate of 40kgh−1. We also found that absorption mass flux increases when tube diameter is reduced and decreases when tube length is increased.

On prediction of heat exchanger performance for latent heat recovery using flue gas

The new type heat exchanger, in which fuel gas flows inside thin tubes and water is shell-side, was proposed to develop the performance and compactness of shell & tube type heat exchanger for latent heat recovery from flue gas. The effects of tube diameter (1.0~5.0 mm) and heat exchanging length (7~100 mm) on the heat transfer characteristics of a single tube were systematically investigated. Moreover, the variations of gas inlet temperature or velocity conditions are studied considering the diverse usage of the gas water heater. It was shown that the usage of thinner tubes was remarkably effective to achieve high performance. That is, since the steep temperature drop near inlet occurred and high heat transfer rate was realized for thinner tubes of 1.0mm and 2.0mm in inner diameter compared with thicker tubes. In addition, the increase in the volumetric heat transfer area in thin tube type heat exchanger contributed to the compactness. Furthermore, the non-dimensional correlations concerning non-dimensional bulk mean temperature and specific enthalpy are proposed by using the ratio of effective tube length and thermal entrance region and correlate well with the measurement data regardless of diameter or inlet conditions. It is possible to predict the heat exchanger performance by using the correlations. As a result, it was elucidated that the using mini-tubes is remarkably effective to reduce the size of heat exchanger. For example, the volume with 1 mm inner diameter of tubes is approximately 4 percent of that with 5 mm in diameter.

End corrections for rarefied gas flows through circular tubes of finite length

A method to take into account the influence of the inlet/outlet ends on rarefied gas flows through moderately long capillaries proposed previously [Vacuum 97, 26 (2013)] is applied to gas flows through circular tubes. The method is based on the concept of effective tube length, representing a sum of its real length and an increment. To calculate the length increment, a flow field near the inlet/outlet of tube is calculated on the basis of the linearized kinetic equation. It is shown that the value of the length increment is independent of the tube length, but depends only on the rarefaction parameter so that it can be used to obtain accurate predictions of the mass flow rate and the axial pressure distribution without great computational effort. Comparisons with results obtained by considering the complete flow domain have shown the efficiency of the end correction concept.

The effect of tube length on postoperative outcome after glaucoma drainage implant surgery

The effect of tube length on postoperative outcome after glaucoma drainage implant surgery

Pilot experimental study on shell and tube heat exchangers with small-angles helical baffles

In this paper, the experimental comparisons of shell side thermodynamic and hydraulics performance are made among three helical baffles heat exchangers and one segmental baffles heat exchanger. The experiment scale is larger than the previous experimental setup as the diameter of test heat exchangers are 500mm and the effective tube length are 6m; the experiment mainly focuses on the small helical angle scheme as the helical angle ranges from 7° to 25°. Among all the four heat exchangers, both the shell side heat transfer rate and the shell side pressure drop peak when helical angle equals 7°, and the shell side heat transfer rate per unit pressure drop at this angle is the smallest. This phenomenon could be easily illustrated as the concept ‘fluid-flow distance’ is presented. At last, the correlations for the shell side Nusselt number and friction factor are presented as a reference.