Study of Shear Stress on the Surface of an Obstacle Attached to Wall of a Narrow Channel

A numerical study has been carried out to determine the fluid shear stress variation on the surface of an obstacle placed in a narrow channel. In this 2D study the dimension of channel is taken as 100mm x 5mm and flow being laminar with Reynolds Number = 200 and velocity of fluid = 0.4m/s. The dimensions of the obstacle are varied to get 15 different shapes and then the variation of wall shear stress values on their surface obtained using ANSYS 15.0 software is studied. It is found that shear stress is minimum when the obstacle flatness is highest, and minimum when the obstacle flatness is least. Few other notable observations are reckoned. This study predicts that an obstacle caught in the flow will try to attain a shape as flat as possible, if it can change its geometr

Stability of AuSn4_{4} compound in low temperature

$\mathrm{AuSn_4}$ is the example of an orthorhombic compound that exhibits topological properties. Recent XRD measurements reveal an ambiguous nature of the crystal structure, as it can be realized with either Aea2 or Ccca symmetry. Motivated by this, we analyze the dynamical stability of the compound with these symmetries. Interestingly, our main result indicates that $\mathrm{AuSn_4}$ is unstable with both Aea2 and Ccca symmetries, due to the soft modes in the phonon spectra. We find that the $\mathrm{AuSn_4}$ can be stable with Pbcm at low temperatures using the soft mode analysis. We also show that the theoretical electronic spectra are well reproduced, and have a good resemblance with the experimental ARPES spectra. Our findings may be valuable to the theoretical investigations of $\mathrm{AuSn_4}$ in future.Comment: 8 pages, 6 figure

Development of Mathematical Model and Characterization of Internal Surface Obtained by Elasto-Abrasives Magneto-Spiral Finishing (EAMSF)

The implantation of stents and instruments with capillary action demands super-finished internal surfaces of the manufactured product. Elasto-abrasives magneto-spiral finishing (EAMSF) is the attempt made in this paper to enhance finishing productivity by incorporating the abrasive flow in spiral motion due to the presence of the magnetic field. Here, novel impregnated elasto-magnetic abrasive particles (IMPs) are used in a magnetic field-assisted environment to polish the inner walls of the workpiece. In EAMSF, magnetic force provides excess finishing pressure to the abrasives. In contrast, the high-impact polystyrene (HIPS) elasticity absorbs the extra force of the IMPs on the finishing surface. An Indigenous mathematical relation considering the physics of this superfinishing process indicating material removal shows a close resemblance to the experimental results with an error percentage of 1.03 has been developed. The results of the experimentation reveal that 50% concentration of abrasives and a magnetic field density of 18mT yield a superior surface finish with a Ra value equal to 0.053 μm and maximum material removal of 6.9 mg, while in the absence of a magnetic field, excellent surface finish with a Ra=0.266 μm and maximum material removal of 5.4 mg is achieved. In the presence of magnetic field density, significant enhancement of material removal, surface finish, and burr removal is observed. Finishing the surface at 50% abrasive concentration with a magnetic field represents regular finishing, and the trench marks on the original surface are removed after finishing

Incidence of low bone mineral density in patients with advanced prostate cancer before hormonal manipulation

Background: Prostate cancer is the second most commonly diagnosed cancer in men with an estimated 1.3 million cases diagnosed in 2018 according to the most recent International Agency for Research on Cancer (IARC) report.A large proportion of men still present with advanced disease and in this situation androgen deprivation therapy (ADT) is the mainstay of treatment.Prostate cancer is largely androgen-dependent and responds to endocrine therapy. ADT is an effective treatment modality which decreases the rate of disease progression, alleviates symptoms, and prolongs patients’ survival. ADT can be achieved through surgery (i.e., bilateral orchidectomy) or medical therapy (gonadotropin releasing hormone agonists, antagonists and antiandrogens).Methods: With the approval from institutional ethic committee, a case control study was planned at the urology outpatient department (OPD) at SMS Hospital from April 2019 to March 2020. Based on inclusion and exclusion criteria, 44 patients with newly diagnosed advanced prostate cancer and requiring hormone manipulation were enrolled in study. Age matched control (age±2 years) was selected from patients attending urology clinics with conditions other than prostate cancer. Ratio of cases and control was kept 1:1. Written consent was taken from all participants.Results: Total 88 patients were enrolled in study, 44 in each group. The age of patients ranged from 57 to 86 years among the case group and 55–85 among the control group. Mean age of cases was 65.24±6.8 and control was 64.98±7.6 years (p=0.25). Body mass index which is calculated with standard formula (weight in kg/height in meter square) was significantly high among controls (24.20±2.46) in comparison to cases (23.42±2.84). Statistically significant difference was observed among case and control groups for PSA (p=0.0001) and serum calcium (p=0.005) however difference for alkaline phosphatase (ALP), parathyroid hormone (PTH) and vitamin D was found insignificant (p>0.05).Conclusions: Low bone mineral density in patients with advanced prostate cancer before hormonal manipulation is nearly 50%. PSA and serum calcium level were significant different among case and control however this difference was not found for ALP, PTH and vitamin D. Consideration should be given to performing BMD studies in these men before initiating treatment, to avoid or minimize potential bone-related complications in these patients

Numerical simulation of vortex induced vibrations on a circular cylinder at different Reynold’s number

This research investigates the effect of vortex induced vibrations on flow past a circular cylinder for two-dimensional unsteady incompressible flow at different Reynold’s number. The pressure bases steady solver is used for computation along with standard k-ε turbulence model. The change in the lift and drag coefficient with respect to increase in Reynolds number is studied and contours of vorticity are plotted. The pressure distribution on the fixed cylinder for different Reynolds number is also presented. It is found that drag coefficient reduces with the increasing Re and lift coefficient increases up to Reynold’s number 104. Moreover, the pressure difference on the fixed cylinder increases with the increasing Reynold’s number

(N,N) Share Generation using Key Share approach for RGB image in VCS

Visual Cryptography is a secure and unique image encryption technique which protects image based secret. In visual cryptography image is encrypted into shares and in decryption process all or some of shares are super imposed with each other to decrypt the original secret image. In this technique no complex computation is needed for decryption of secret image which is the best advantage of Visual Cryptography Scheme. In this report various types of visual cryptographic techniques are discussed from previous research area. In this proposed system (N, N) VCS is used for encryption. It takes color image as an input and extracts in R, G and B components. After that it generates Key-Mask using Key-Mask generation algorithm which XOR-ed with R, G and B components and gives the key shares. Further XOR operation of these key shares with key mask generates the color shares. In decryption process image is recovered by XOR operation between key mask and color shares. It has a better security features compared to previous one

Sound radiation of simply supported rectangular plate using finite element method

In this paper sound radiation of simply supported rectangular plate has been reported. The novelty in this research paper is a new method is prescribed for sound radiation calculation. The phenomenon of uncoupled structural acoustics have been followed such that structure is the critical part in structural vibration using modal analysis and harmonic response calculation for frequency range of interest 0 to 200 Hz, but in harmonic acoustic analysis the structure does not takes part in physics point of view but is used for only for transferring the normal velocity from wetted surface of the structure to the interface acoustic medium i.e. air. Sound Radiation parameters like Sound Pressure Level, Sound Power Level and Sound Radiation efficiency has been reported. Upon comparing the results with that from I. Zaman’s literature, it is found that the results are quite varying due to the fact the speed of sound in air as taken in literature is unjustified. So true simulation using correct data has been carried out in this paper and sound radiation results has been reported for frequency range of interest 0 to 200 Hz. It is found that the maximum sound pressure level is 72 dB and maximum sound power level is 78 dB which is suitable for noiseless environment

Staging Orthodontic Aligners for Complex Orthodontic Tooth Movement

The recent trend in orthodontics has shown an increased shift toward aligner therapy. For years, orthodontists have used fixed preadjusted appliances for orthodontic treatment. Even though fixed appliances have been highly efficient in the treatment of orthodontic malocclusions, they are not as esthetic as clear aligners. The purpose of this article is to review the staging of orthodontic tooth movement (OTM) with aligner therapy