Pressure fluctuations on the surface of a cylinder in uniform flow

The problem of determining the pressure fluctuations induced on the surface of a cylinder by the fluctuating wake behind it is formulated. A formal solution relating the unsteady surface pressure field to the velocity field in the wake is derived and used to obtain general results independent of cylinder shape and Reynolds number. The case of the circular cylinder is then examined in detail

An experimental investigation of the flow past a finite circular cylinder at a low subcritical Reynolds number

Results of hot wire measurements made in the near wake at a Reynolds number of 9955 are reported. The measurements include the mean velocity profiles, root mean square values of the velocity fluctuations, frequency spectra, and velocity cross correlations. The mean velocity profiles were used to determine the wake width, whose variation in the downstream and spanwise directions was examined. It is observed that close to the cylinder, the wake is narrower toward the free end than it is away from it, while further downstream the wake is wider toward the tip than it is away from it. It is found that the flow over the span can be characterized by four regions: a tip region where vortex shedding occurs at a lower frequency than that prevalent for away from the tip; an intermediate region adjacent to the first one where a frequency component of a nonshedding character is present; a third region characterized by a gradually increasing shedding frequency with increasing distance from the tip; and a two dimensional region where the shedding frequency is constant

The virtual human face – superimposing the simultaneously captured 3D photorealistic skin surface of the face on the untextured skin image of the CBCT Scan

The aim of this study was to evaluate the impact of simultaneous capture of the three-dimensional (3D) surface of the face and cone beam computed tomography (CBCT) scan of the skull on the accuracy of their registration and superimposition. 3D facial images were acquired in 14 patients using the Di3d (Dimensional Imaging, UK) imaging system and i-CAT CBCT scanner. One stereophotogrammetry image was captured at the same time as the CBCT and another one hour later. The two stereophotographs were then individually superimposed over the CBCT using VRmesh. Seven patches were isolated on the final merged surfaces. For the whole face and each individual patch; maximum and minimum range of deviation between surfaces, absolute average distance between surfaces, and standard deviation for the 90th percentile of the distance errors were calculated. The superimposition errors of the whole face for both captures revealed statistically significant differences (P=0.00081). The absolute average distances in both separate and simultaneous captures were 0.47mm and 0.27mm, respectively. The level of superimposition accuracy in patches from separate captures ranged between 0.3 and 0.9mm, while that of simultaneous captures was 0.4mm. Simultaneous capture of Di3d and CBCT images significantly improved the accuracy of superimposition of these image modalities

Sensorimotor adaptation to auditory perturbation of speech is facilitated by noninvasive brain stimulation

Repeated exposure to disparity between the motor plan and auditory feedback during speech production results in a proportionate change in the motor system’s response called auditory-motor adaptation. Artificially raising F1 in auditory feedback results in a concomitant decrease in F1 during speech production. Transcranial direct current stimulation (tDCS) can be used to alter neuronal excitability in focal areas of the brain. The present experiment explored the effect of noninvasive brain stimulation applied to the speech premotor cortex on the timing and magnitude of adaptation responses to artificially raised F1 in auditory feedback. Participants (N = 18) completed a speaking task in which they read target words aloud. Participants' speech was processed to raise F1 by 30% and played back to them over headphones in real time. A within-subjects design compared acoustics of participants’ speech while receiving anodal (active) tDCS stimulation versus sham (control) stimulation. Participants' speech showed an increasing magnitude of adaptation of F1 over time during anodal stimulation compared to sham. These results indicate that tDCS can affect behavioral response during auditory-motor adaptation, which may have translational implications for sensorimotor training in speech disorders

Sampling Technique and Minimization of Inspection Errors in Leather Sorting

         Leather processing is one of the oldest industries. It involves processing of animals skins and hides for use in various products. The objectives of this study were to adopt a Sampling Plan Technique by comparison of various Sampling Plans in order to identify the best to be used in inspection process. This is to overcome human fatigue, to minimize the inspection time and to draw the Operating Characteristic Curve. A lot of 18000 pieces of wet blue goat skins for export was inspected for quality assurance to the standard quality level. These were set to be 10% & 5% for acceptable and rejects level by the supplier and customer respectively. Then various Acceptance Sampling Plans were compared then the probability of acceptance for lot quality level was evaluated using Operating Characteristic Curve. The results Showed that for quality assurance the best plan was when the lot size (N) was equal to  18000, the sample size (n) was equal to 350 and number of defects (c) was equal to 10. It is recommended that Acceptance Sampling Plan technique can be adopted by all Sudanese tanneries and related fields.           &nbsp

The place-cell representation of volumetric space in rats

Place cells are spatially modulated neurons found in the hippocampus that underlie spatial memory and navigation: how these neurons represent 3D space is crucial for a full understanding of spatial cognition. We wirelessly recorded place cells in rats as they explored a cubic lattice climbing frame which could be aligned or tilted with respect to gravity. Place cells represented the entire volume of the mazes: their activity tended to be aligned with the maze axes, and when it was more difficult for the animals to move vertically the cells represented space less accurately and less stably. These results demonstrate that even surface-dwelling animals represent 3D space and suggests there is a fundamental relationship between environment structure, gravity, movement and spatial memory

Application of Process Quality Control in Leather Industry

Quality Control is the regulatory process measuring actual quality performance, comparing it with standards, and rectifying the difference. The objective of this study was to design control charts for raw and export goat skins to ensure that non-defective items are used, and to ensure that defective items are not passed to customers. Ten random samples of raw goat skins of different sizes (32 – 125pieces) were taken and inspected, and then a control chart was drawn. For outgoing wet blue goat skin, ten samples of the same size each of (125pieces) were taken and inspected then a control chart was drawn. The results were as follow; the process involved in delivery of raw skins was out of control, because the proportion defective (0.2080) in one of the samples was located above the upper action limit. The process of outgoing skin showed stability on control chart because all samples were within control limits