Agitation of Complex Fluids in Cylindrical Vessels by Newly Designed Anchor Impellers

The fluid flows and power consumption in a vessel stirred by anchor impellers are investigated in this paper. The case of rheologically complex fluids modeled by the Bingham-Papanastasiou model is considered. New modifications in the design of the classical anchor impeller are introduced. A horizontal blade is added to the standard geometry of the anchor, and the effect of its inclination angle (α) is explored. Four geometrical configurations are realized, namely: α = 0°, 20°, 40°, and 60°. The effects of the number of added horizontal blades, Reynolds number, and Bingham number are also examined. The obtained findings reveal that the most efficient impeller design is that with (case 4) arm blades inclined by 60°.This case allowed the most expansive cavern size with enhanced shearing in the whole vessel volume. The effect of adding second horizontal arm blades (with 60°) gave better hydrodynamic performance only with a slight increase in power consumption. A significant impact of Bingham number (Bn) was observed, where Bn = 5 allowed obtaining the lowest power input and most expansive well-stirred region.

CFD and Thermal Analysis of Exhaust Manifold and Exhaust Header for a 6 Cylinder Inline Engine: A Review

Exhaust Manifold and Exhaust Header is one of the important additives of IC engine for enhancing the volumetric performance. The volumetric performance of the engine may be expanded with the aid of using decreasing the backpressure and growing the exhaust pace with inside the exhaust manifold and header. These studies examine the float via unique fashions of exhaust manifold and exhaust header the use of CFD and Thermal evaluation for a 6 cylinder inline engine. The layout of exhaust manifold is changed to get gold standard geometry. The evaluation consequences of fashions are as compared for returned stress and pace of exhaust fuel line. By evaluating the consequences of fashions the lower in returned stress is located which make sure development in volumetric performance of the engine. Keywords: Exhaust Manifold, Exhaust Header, CFD Analysis, Thermal Analysis, 6-Cylinder Inline Engine

Determination of in situ detection efficiency for IM-NAA of non-standard geometrical samples

The k0-based internal mono-standard (IM) method was first proposed for the concentration analysis of samples of non-standard geometry in the 2000s. The method has demonstrated several advantages such as the elimination of gamma-ray self-attenuation and geometrical effects. On the other hand, the accuracy of the method principally depends on the in situ relative detection efficiency, which requires to be obtained in each measurement. Therefore, the relative detection efficiency is always under consideration for the improvement of the analysis results. The present paper describes a simple and automatic procedure for the determination of the relative efficiency using one or more activation products emitting gamma rays over a considered range of the spectrum. The procedure can be applied for INAA and PGNAA analysis.

Set Partitioning in Hierarchical Trees for Point Cloud Attribute Compression

<div>We propose an embedded attribute encoding method for point clouds based on set partitioning in hierarchical trees (SPIHT) [1]. The encoder is used with the region-adaptive hierarchical transform [2] which has been a popular transform for point cloud coding, even included in the standard geometry-based point cloud coder (G-PCC) [3],[4]. The result is an encoder that is efficient, scalable, and embedded. That is, higher compression is achieved by trimming the full bit-stream. G-PCC’s RAHT coefficient prediction prevents the straightforward incorporation of SPIHT into G-PCC. However, our results over other RAHT based coders are promising, improving over the original, nonpredictive RAHT encoder, while providing the key functionality of being embedded.</div>

Set Partitioning in Hierarchical Trees for Point Cloud Attribute Compression

<div>We propose an embedded attribute encoding method for point clouds based on set partitioning in hierarchical trees (SPIHT) [1]. The encoder is used with the region-adaptive hierarchical transform [2] which has been a popular transform for point cloud coding, even included in the standard geometry-based point cloud coder (G-PCC) [3],[4]. The result is an encoder that is efficient, scalable, and embedded. That is, higher compression is achieved by trimming the full bit-stream. G-PCC’s RAHT coefficient prediction prevents the straightforward incorporation of SPIHT into G-PCC. However, our results over other RAHT based coders are promising, improving over the original, nonpredictive RAHT encoder, while providing the key functionality of being embedded.</div>

Improving Accuracy of Checkshot Time-Depth by Applying Advanced Model-Based Correction for Rig-Source Survey on a Highly Inclined Well

In seismic exploration, checkshot survey is an important method to obtain accurate time-depth profile for depth-to-time or time-to-depth conversion. However, the standard geometry correction for a rig-source survey in a high-inclination well will not provide a reliable time-depth result due to ray-bending effect. The objective of this study was to enhance the accuracy of the time-depth velocity by utilizing an advanced technique called model-based correction or pseudo walk-above simulation. To obtain model-based vertical times, a flat-layered velocity model was built by using the checkshot velocities as initial guess. The model was then inverted to match the observed checkshot travel times, which were the actual measurement of travel path from source to receivers. The model was iterated to minimize the residual between the observed and modeled travel times in a least-square sense. A pseudo walk-above checkshot simulation was run on the inverted model by positioning the sources exactly on top of the receivers to get the vertical times, which were used for the final time-depth relationship and further image processing. The residual times of less than 1 millisecond (ms) were observed between the actual measured transit times and modeled travel times from a fixed source to the receivers in the inverted model. This demonstrated the inverted model was realiable to use for obtaining more accurate vertical time-depth through pseudo walk-above checkshot simulation. This optimal inverted model was considered as the best estimation of the true earth model in this case. A comparison of modeled vertical times estimated through the pseudo walk-above simulation and calculated vertical times using standard geometry correction were done. The difference between the two scenarios was 6 ms one-way time (OWT) demonstrated the reduction of 6 ms uncertainty of using the advanced model-based correction versus the standard geometry correction. In short, the advanced technique delivered more reliable time-depth velocity information to reduce depth uncertainties for drilling operation. The walk-above or vertical incidence checkshot survey, which required boat and navigation system, was unable to acquire in a highly deviated well due to very bad weather conditions. The rig-source survey was carried out instead of employing the walk-above survey in this project. The standard geometry correction using simple trigonometry was not able to provide the correct vertical times. The advanced model-based correction was the optimal solution to improve the accuracy of checkshot time-depth velocity data.

Frame Work on an Injection Molding Rejuvenation Technique for Cable Insulation Failure

Rejuvenation technique on cable insulation failures is a hot topic in improving production benefits for electric related enterprises. Breaking the traditional thought of repair action without extensive former damage in scale of the cable insulation, the proposed technique starts from the local standard geometry elimination on insulation or sheaths around cable insulation failure section(s). And then, one standard injection molding technique is applied for rejuvenation on eliminated insulation no matter of the failure resulting from water tree or local mechanical damage or other modes. By this advancement, an injection molding technique is perfectly developed for rejuvenation on cable insulation failure. Frame work on this technigue is hear introduced and it consists of three branches including injection molding material development, standard injection plastic molding technique, and coded quality approval regularities. Realizability and reliability of the present technigue have been verified by sampling testing to expect to be wide applied in production.

Determination of Gamma-Ray Shielding Parameters for Concretes and Dosimeters Using MCNPX

Gamma-ray shielding parameter for some concretes and dosimeters having large scale applications in radiological protection are presented using MCNPX (version 2.4.0) at different energies. The MCNPX results are compared with experimental, MCNP and XCOM data, and good agreement is being noted. Present study indicates that MCNPX simulation method is suitable and reliable simulation tool to be used as an alternative method for the investigation of gamma-ray interaction. The present geometry can be used as standard geometry for MCNPX simulation for low- as well as high-Z materials.

Numerical and Experimental Study on Combined Seals With the Consideration of Stretching Effects

Combined seals, as a kind of reciprocating seals, are widely used in hydraulic systems. The combined seal usually contains two or more elements to achieve the sealing function. Not only the interference fit between the seal and the rod/groove should be considered, but the assembling parameters between the inner sealing elements are also essential to be investigated. Stretching ratio, as an indicator for the interference fit, usually exerts a significant influence on the sealing performance. However, in the studies of stretching effects on combined seals, the traditional axisymmetric modeling method will introduce the overstretching problems, resulting in large errors. To overcome this problem, this paper proposed a putter-movement method, where an extra putter is introduced into the model, and a mixed-lubrication theory was employed to study macro and micro characteristics among the sealing zone. As a typical kind of combined seals, the VL seal is utilized as the research object, and the material’s plastic effects are included in the reciprocating-seal modeling for the first time. The numerical results are compared with the experimental data, and good agreements are obtained. The proposed method is then employed to discuss the sealing characteristics under different interference-fit conditions systematically. The results indicate that the stretching mainly affects the contact pressure on the cavity side. Compared to the performance of the seal with the standard geometry, in the extra-stretching condition, the leakage is increased, but the friction is decreased.