Numerical investigation of yaw angle effects on propulsive characteristics of podded propulsors

Shamsi, Reza,Ghassemi, Hassan The Society of Naval Architects of Korea 2013 International Journal of Naval Architecture and Oc Vol.5 No.2

The present paper deals with the problems of yaw angle effects on podded propulsor performance. The study aims at providing insights on characteristics of podded propulsors in azimuthing condition. In this regard, a wide numerical simulation that concerned yaw angle effect measurement on podded propeller performance was performed. The Reynolds-Averaged Navier Stokes (RANS) based solver is used in order to study the variations of hydrodynamic characteristics of podded propulsor at various angles. At first, the propeller is analyzed in open water condition in absence of pod and strut. Next flow around pod and strut are simulated without effect of propellers. Finally, the whole unit is studied in zero yaw angle and azimuthing condition. Structured and unstructured mesh techniques are used for single propeller and podded propulsor. The performance curves of the propeller obtained by numerical method are compared and verified by the experimental results. The characteristic parameters including the torque and thrust of the propeller, the axial force and side force of unit are presented as function of velocity advance ratio and yaw angle. The results shows that the propeller thrust, torque and podded unit forces in azimuthing condition depend on velocity advance ratio and yaw angle.

Determination of an Effective Wedge Angle by Combination of Two Arbitrary Universal Wedge Fields in Radiation Therapy of Cancer Patients with Megavoltage Photon Beams

Shamsi, Azin,Birgani, Mohammad Javad Tahmasebi,Behrooz, Mohammad Ali,Arvandi, Sholeh,Fatahiasl, Jafar,Maskny, Reza,Abdalvand, Neda Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.1

Background: Wedge filters are commonly used in radiation oncology for eliminating hot spots and creating a uniform dose distribution in optimizing isodose curves in the target volume for clinical aspects. These are some limited standard physical wedges ($15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$),or creating an arbitrary wedge angle, like motorized wedge or dynamic wedge,${\ldots}$ The new formulation is presented by the combination of wedge fields for determining an arbitrary effective wedge angles. The isodose curves also are derived for these wedges. Materials and Methods: we performed the dosimetry of Varian Clinac 2100C/D with Scanditronix Wellhofer water blue phantom, CU500E, OmniPro - Accept software and 0.13cc ionization chamber for 6Mv photon beam in depth of 10cm (reference depth) for universal physical wedges ($15^{\circ}$, $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$) and reference field $10.10cm^2$. By combining the isodose curve standard wedge fields with compatible weighting dose for each field, the effective isodose curve is calculated for any wedge angle. Results: The relation between a given effective wedge angle and the weighting of each combining wedge fields was derived. A good agreement was found between the measured and calculated wedge angles and the maximum deviation did not exceed $3^{\circ}$. The difference between the measured and calculated data decreased when the combined wedge angles were closer. The results are in agreement with the motorized single wedge appliance in the literature. Conclusions: This technique showed that the effective wedge angle that is obtained from this method is adequate for clinical applications and the motorized wedge formalism is a special case of this consideration.

A Multicenter Matched Case Control Study of Breast Cancer Risk Factors among Women in Karachi, Pakistan

Shamsi, Uzma,Khan, Shaista,Usman, Sheheryar,Soomro, Saleem,Azam, Iqbal Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.1

Background: Breast cancer (BC), the most common female cancer in Pakistan, is associated with a very high mortality. However, the roles of individual risk factors for BC among Pakistani women are still controversial. To assess potential risk factors for BC, a matched case-control study was conducted in two tertiary care hospitals of Karachi, Pakistan. Materials and Methods: The study population included 297 pathologically confirmed incident cases of BC patients diagnosed between January 2009 and December 2010. 586 controls without any history of BC were matched on hospital and ${\pm}5$ years of ages. Results: Positive family history of BC (MOR=1.72; 95%CI: 1.10, 2.80 for first degree vs. none), single marital status (MOR=1.55; 95%CI: 1.10, 2.39 for single/divorced/widowed women vs. married women), older age at menopause (MOR=3.92; 95%CI: 2.52, 6.18 for menopausal women aged below 45 years, MOR=6.42; 95%CI: 3.47, 11.98 for menopausal women above 45 years of age compared with premenopausal women) conferred an increased risk of BC for women. Increasing parity decreased the risk of BC (MOR=0.90; 95%CI: 0.85, 0.97 for each live birth). Intake of Vitamin D supplements (MOR=0.30; 95%CI: 0.12, 0.81 for ${\leq}3$ years and MOR=0.27; 95%CI: 0.13, 0.56 for >3 years) was protective compared to non-users of Vitamin D. Conclusions: This study confirmed only few of the recognized risk factors in Pakistani women. The protective effect of Vitamin D is important from public health perspective and needs to be further explored through a randomized controlled trial.

The first biopolymer-wrapped non-carbon nanotubes

Shamsi, Mohtashim H,Geckeler, Kurt E IOP Pub 2008 Nanotechnology Vol.19 No.7

<P>DNA-wrapped halloysite nanotubes were obtained by a mechanochemical reaction in the solid state. The characterization by scanning electron microscopy showed that the nanotubes were cut into shorter lengths and were completely covered with DNA. This resulted in a high aqueous solubility of the product with stability of the solution for about 6 weeks. The nanotubes were cut to different fractions with lengths of 200–400 nm (30–40%), 400–600 nm (10–20%) and 600–800 nm (5–10%) after ball milling. FTIR spectroscopic analysis shows that the DNA in the product remained intact. This straightforward technique for obtaining water-soluble halloysite nanotubes by a solid-state reaction has great potential for biomedical applications of nanotubes.</P>

Comparing Two Methods of Cryotherapy and Intense Pulsed Light with Triamcinolone Injection in the Treatment of Keloid and Hypertrophic Scars: A Clinical Trial

Simin Shamsi Meymandi,Mahmood Moosazadeh,Azadeh Rezazadeh 질병관리본부 2016 Osong Public Health and Research Persptectives Vol.7 No.5

Objectives: Keloid and hypertrophic scars are abnormal manifestations of wounds that occur following skin injuries in the form of local proliferation of fibroblasts and increased production of collagen. There are several ways to cure these scars; treatment must be selected based on the nature of the scars. In this clinical trial, two methods-cryotherapy and intense pulsed light (IPL)-are compared in the treatment of scars, and the results are presented in terms of improvement level, complications, and patient satisfaction. Methods: This clinical trial was conducted in southeastern Iran. The intervention group included scars that underwent the IPL method and the control group, which consisted of scars that were subjected to cryotherapy. In both methods, intralesional corticosteroid injection was administered. To select samples, the easy sampling method was used. To determine the expected outcomes, the criteria determined in the Vancouver scar scale were used. Data were analyzed using the Mix Model, chi-square test, and t test. Results: In this study, 166 samples of keloid and hypertrophic scars were cured using two methods (Cryotherapy, 83; IPL, 83). The recovery rate was higher in the Cryotherapy group than in the IPL group (p > 0.05), and the incidence of complications was also higher in the Cryotherapy group (14.5% vs. 12%). Moreover, patients were more satisfied, although not significantly so, with the cryotherapy method (p = 0.09). Conclusion: Both methods were highly successful in curing scars; participants were totally satisfied with both methods.

Synergism effect of collectors on copper recovery in flotation of copper smelting slags

Mostafa Shamsi,Mohammad Noaparast,Seied Ziadin Shafaie,Mahdi Gharabaghi 한국자원공학회 2016 Geosystem engineering Vol.19 No.2

Study on the effect of collectors synergism on flotation recovery of copper from copper smelting slags has been described in this paper. After analysis of flotation tests, modeling of copper recovery from slags containing this metal was done. Following the model validation, optimization of effective parameters on Cu recovery was performed. Results of optimization showed that when 10 g/t Z6 as collector and 50 g/t AERO 3477 as modifier were used separately, copper recovery (62.23%) was obtained under optimal conditions. To increase the copper recovery, a mixture of 6 g/t Z6, 4 g/t Z11, 30 g/t AERO 3477, and 20 g/t AERO 208 were used to determine synergism effect of collectors on copper recovery. After doing flotation tests at optimal conditions with mixture of collectors, copper recovery was increased to 80.27%.

Effects of High White and Brown Sugar Consumption on Serum Level of Brain-Derived Neurotrophic Factor, Insulin Resistance, and Body Weight in Albino Rats

Ali Shamsi-Goushki,Zinat Mortazavi,Mohammad Ali Mirshekar,Fatemeh Behrasi,Nasroallah Moradi-Kor,Rasul Taghvaeefar 대한비만학회 2020 The Korean journal of obesity Vol.29 No.4

Background: In recent decades, consumption of simple sugars has increased dramatically, which contributes to health problems including insulin resistance and obesity. In this study, we investigated the effects of high concentrations of white sugar (WS) and brown sugar (BS) on serum concentration of brain-derived neurotrophic factor (BDNF), insulin resistance, and body weight in albino rats. Methods: Twenty-four male Wistar rats were randomly divided into three groups: control, a group treated with 15% WS, and a group treated with 15% BS. Rats were given WS and BS by gavage (daily) for 42 days. At the end of the intervention period, serum level of BDNF, insulin resistance, and body weight were measured. Results: Body weight and insulin resistance were significantly increased and serum BDNF level was decreased in both WS and BS groups compared to the control group (P<0.05). In the WS-treated rats, the amount of changes in the insulin resistance, body weight, and serum BDNF level was greater compared to that in BS-treated (P< 0.05). Conclusion: Due to the adverse effects of consuming high levels of WS and BS on serum level of BDNF, insulin resistance, and body weight, high intakes of these sweeteners are not recommended.

Numerical investigation of yaw angle effects on propulsive characteristics of podded propulsors

Reza Shamsi,Hassan Ghassemi 대한조선학회 2013 International Journal of Naval Architecture and Oc Vol.5 No.2

The present paper deals with the problems of yaw angle effects on podded propulsor performance. The study aims at providing insights on characteristics of podded propulsors in azimuthing condition. In this regard, a wide numerical simulation that concerned yaw angle effect measurement on podded propeller performance was performed. The Reynolds-Averaged Navier Stokes (RANS) based solver is used in order to study the variations of hydrodynamic characteristics of podded propulsor at various angles. At first, the propeller is analyzed in open water condition in absence of pod and strut. Next flow around pod and strut are simulated without effect of propellers. Finally, the whole unit is studied in zero yaw angle and azimuthing condition. Structured and unstructured mesh techniques are used for single propeller and podded propulsor. The performance curves of the propeller obtained by numerical method are compared and verified by the experimental results. The characteristic parameters including the torque and thrust of the propeller,the axial force and side force of unit are presented as function of velocity advance ratio and yaw angle. The results shows that the propeller thrust, torque and podded unit forces in azimuthing condition depend on velocity advance ratio and yaw angle.

Effects of Geometry and Operating Fluid on the Expansion Behavior of Liquid-Solid Fluidized Beds

Mohsen Mozafari-Shamsi,Alireza Malooze,Mohammad Sefid,Mostafa Soroor,Ehsan Mehrabi Gohari 한국화학공학회 2023 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.61 No.2

Fluidized beds have been widely used in industrial applications, which in most of them, the operating fluid is non-Newtonian. In this study, the combination of the lattice Boltzmann method (LBM) and the smoothed profile method has been developed for non-Newtonian power-law fluids. The validation of the obtained model were investigated by experimental correlations. This model has been used for numerical studying of changing the operating fluid and geometrical parameters on the expansion behavior in liquid-solid beds with both Newtonian and non- Newtonian fluids. Investigations were performed for seven different geometries, one Newtonian, and two non- Newtonian fluids. The power-law index was in the range of 0.8 to 1, and the results for the Newtonian fluidized beds show more porosity than the non-Newtonian ones. Furthermore, increasing the power-law index resulted in enhancing the bed porosity. On the other hand, bed porosity was decreased by increasing the initial bed height and the density of the solid particles. Finally, the porosity ratio in the bed was decreased by increasing the solid particle diameter.

Thermodynamic Study of Solid Oxide Electrolysis Cell (SOEC) System Integrated with External Steam for Efficient Hydrogen Production

Syed Shaheryar Ali Shamsi,Tak-Hyoung Lim 한국표면공학회 2023 한국표면공학회 학술발표회 초록집 Vol.2023 No.11-1