Improving wing aeroelastic characteristics using periodic design

Badran, Hossam T.,Tawfik, Mohammad,Negm, Hani M. Techno-Press 2017 Advances in aircraft and spacecraft science Vol.4 No.4

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness, and inertia forces on a structure. In an aircraft, as the speed of the flow increases, there may be a point at which the structural damping is insufficient to damp out the motion which is increasing due to aerodynamic energy being added to the structure. This vibration can cause structural failure, and therefore considering flutter characteristics is an essential part of designing an aircraft. Scientists and engineers studied flutter and developed theories and mathematical tools to analyze the phenomenon. Strip theory aerodynamics, beam structural models, unsteady lifting surface methods (e.g., Doublet-Lattice) and finite element models expanded analysis capabilities. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. This may reduce the vibration level of the structure, and hence improve its dynamic performance. In this paper, for the first time, we analyze the flutter characteristics of a wing with a periodic change in its sandwich construction. The new technique preserves the external geometry of the wing structure and depends on changing the material of the sandwich core. The periodic analysis and the vibration response characteristics of the model are investigated using a finite element model for the wing. Previous studies investigating the dynamic bending response of a periodic sandwich beam in the absence of flow have shown promising results.

Improving aeroelastic characteristics of helicopter rotor blades in forward flight

Badran, Hossam T.,Tawfik, Mohammad,Negm, Hani M. Techno-Press 2019 Advances in aircraft and spacecraft science Vol.6 No.1

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of a helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter forward speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

Improving aeroelastic characteristics of helicopter rotor blades in hovering

Badran, Hossam T.,Tawfik, Mohammad,Negm, Hani M. Techno-Press 2021 Advances in aircraft and spacecraft science Vol.8 No.3

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness, and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter rotation speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

Improving aeroelastic characteristics of helicopter rotor blades in hovering

Badran, Hossam T.,Tawfik, Mohammad,Negm, Hani M. Techno-Press 2021 Advances in aircraft and spacecraft science Vol.8 No.3

Flutter is a dangerous phenomenon encountered in flexible structures subjected to aerodynamic forces. This includes aircraft, helicopter blades, engine rotors, buildings and bridges. Flutter occurs as a result of interactions between aerodynamic, stiffness, and inertia forces on a structure. The conventional method for designing a rotor blade to be free from flutter instability throughout the helicopter's flight regime is to design the blade so that the aerodynamic center (AC), elastic axis (EA) and center of gravity (CG) are coincident and located at the quarter-chord. While this assures freedom from flutter, it adds constraints on rotor blade design which are not usually followed in fixed wing design. Periodic Structures have been in the focus of research for their useful characteristics and ability to attenuate vibration in frequency bands called "stop-bands". A periodic structure consists of cells which differ in material or geometry. As vibration waves travel along the structure and face the cell boundaries, some waves pass and some are reflected back, which may cause destructive interference with the succeeding waves. In this work, we analyze the flutter characteristics of helicopter blades with a periodic change in their sandwich material using a finite element structural model. Results shows great improvements in the flutter rotation speed of the rotating blade obtained by using periodic design and increasing the number of periodic cells.

Impact of peripheral blood mononuclear cells preconditioned by activated platelet supernatant in managing gastric mucosal damage induced by zinc oxide nanoparticles in rats

Darwish Badran,Ayman El-Baz El-Agroudy,Amira Adly Kassab,Khaled Saad El-Bayoumi,Zienab Helmy Eldken,Noha Ramadan Mohammed Elswaidy 대한해부학회 2024 Anatomy & Cell Biology Vol.57 No.1

The world has witnessed tremendous advancements in nano-base applications. Zinc oxide nanoparticles (ZON) are widely used in food industry and medicine. Although their application is of important value, they may cause toxicity to body tissues. Peripheral blood mononuclear cells (PBMCs) proved its efficacy in tissue regeneration especially when it is preconditioned by activated platelet supernatant (APS). The aim of this study is to evaluate the effect of ZON on the gastric mucosa and the therapeutic role of the PBMCs preconditioned by APS in rats. Ten rats were donors and fifty rats were recipients. The recipients were divided into; control group, ZON group (10 mg/kg/day orally for five days) and preconditioned PBMCs group (1×107 once intravenously 24 hours after ZON). Gastric specimens were processed for histological, immunohistochemical, biochemical and quantitative real-time polymerase chain reaction studies. ZON group showed marked structural changes in the gastric mucosa. There was desquamation or deep ulceration of the epithelium. Cytoplasmic vacuoles and pyknotic nuclei were in glandular cells. Reduced proliferating cell nuclear antigen and increased tumor necrosis factor-α were in epithelial cells. There were significant elevation in malondialdahyde and reduction in glutathione, superoxide dismutase, and catalase. Enhancement in mRNA expression of nuclear factor kappa-B and cyclooxygenase-2 was detected. The preconditioned PBMCs group showed significant improvement of all parameters. So, ZON had cytotoxic effects on the gastric mucosa and the preconditioned PBMCs had a therapeutic effect on gastric mucosal damage after ZON.

Localization of S-100 proteins in the testis and epididymis of poultry and rabbits

Ahmed Abd Elmaksoud,Mahmoud Badran Shoeib,Hany E S Marei 대한해부학회 2014 Anatomy & Cell Biology Vol.47 No.3

The present investigation was conducted to demonstrate S-100 protein in the testis and epididymis of adult chickens, Sudani ducks, pigeons, and rabbits. This study may represent the first indication for the presence of S-100 in the male reproductive organs of these species and might therefore serve as a milestone for further reports. In the testis of chickens, pigeons and rabbits, intense S-100 was seen in Sertoli cells. S-100 was also seen in the endothelial lining of blood vessels in rabbit testis. On the contrary, no S-100 reaction was detected in the Sertoli cells of Sudani ducks. In epididymis, the localization of S-100 had varied according to species studied; it was seen in the basal cells (BC) of epididymal duct in duck, non-ciliated cells of the distal efferent ductules in pigeons and ciliated cells of the efferent ductules and BC of rabbit epididymis. Conversely, S-100 specific staining was not detected in the epithelial lining of the rooster and pigeon epididymal duct as well as the principal cells of the rabbit epididymis. In conclusion, the distribution of the S-100 proteins in the testis and epididymis might point out to its roles in the male reproduction.

Azimuthal Angle Scan Distribution, Third Order Response, and Optical Limiting Threshold of the Bismarck Brown Y:PMMA Film

Fadhil Abass Tuma,Hussain Ali Badran,Harith Abdulrazzaq Hasan,Riyadh Chassib Abul-Hail 한국광학회 2023 Current Optics and Photonics Vol.7 No.6

This paper studies various roughness parameters, besides waviness, texture, and nonlinear parameters of Bismarck brown Y (BBY)-doped Poly(methyl methacrylate) (PMMA) films based on the computed values of optical limiting (OL) threshold power and nonlinear refractive index. The films’ morphology, grain size, and absorption spectra were investigated using atomic force microscopy in conjunction with ultraviolet-visible (UV-Vis) spectrophotometer. The particle size of the films ranged between 4.11–4.51 mm and polymer films showed good homogeneity and medium roughness, ranging from 1.11–4.58 mm.A polymer film’s third-order nonlinear optical features were carried out using the Z-scan methodology. The measurements were obtained by a continuous wave produced from a solid-state laser with a 532 nm wavelength. According to the results, BBY has a nonlinear refractive index of 10 −6 cm 2 /W that is significantly negative and nonlinear. The optical limiting thresholds are roughly 10.29, 13.52, and 18.71 mW, respectively. The shift of nonlinear optical features with the film’s concentration was found throughout the experiment Additionally, we found that the polymer samples have outstanding capabilities for restricting the amount of optical power that may be transmitted through them. We propose that these films have the potential to be used in a wide variety of optoelectronic applications, including optical photodetectors and optical switching.

Ameliorative effects of curcumin and caffeic acid against short term exposure of waterpipe tobacco smoking on lung, heart and kidney in mice

Alia Khwaldeh,Ali Abu Siyam,Ahmed Alzbeede,Mohammad Farajallah,Ziad Shraideh,Darwish Badran 대한해부학회 2021 Anatomy & Cell Biology Vol.54 No.1

This study aims to evaluate the chemopreventive activity of two antioxidants (curcumin [CUM] and caffeic acid [CAF]), focusing on how these antioxidants could reduce cytotoxicity induced by short term secondhand exposure of waterpipe tobacco smoking. Forty-eight adult male BALB/c albino mice were equally divided into four groups. Antioxidants were delivered intraperitoneally, and the exposure to waterpipe smoking (WPS) was performed using a smoking machine. This experiment lasts for 14 consecutive days. Serum were collected from mice before dissection to quantify the activity of some liver enzymes, kidney function tests and proinflammatory cytokines. Lung, heart, and kidney were isolated and processed for light microscopy technique. Parallel treatment of CUM or CAF along with exposure to WPS showed less inflammation, less vacuolized, and more inflated alveoli, less deteriorations in cortex part of kidney, and less disintegration of cardiac myofibers in comparison to waterpipe only. Besides, CUM and CAF significantly reduced the activity of aspartate aminotransferase and proinflammatory cytokines. CUM and CAF were found to have anti-inflammatory and ameliorative effects against the cytotoxicity induced by exposure to waterpipe tobacco smoking, and CUM showed better chemopreventive activity than CAF.

The best vein to be accessed based on descriptive study of dorsal metacarpal vein

Muna A. Salameh,Amjad T. Shatarat,Darwish H. Badran,Mhmoud A. Abu-Abeeleh,Islam M. Massad,Amjad M. Bani-Hani 대한해부학회 2019 Anatomy & Cell Biology Vol.52 No.4

It is well known that the most common sites for venous access are the superficial veins of the upper limb, particularly dorsal metacarpal veins and median cubital vein. Although dorsal metacarpal veins are the first choice for venous cannulation, there is scarce information about their anatomic variation. Hence, detailed anatomical information about these veins will improve the anatomic knowledge of the health care providers. Subsequently, this study was designed to study the dorsal metacarpal veins and to determine the most prominent dorsal metacarpal vein. A cross sectional study of 402 subjects (804 hands), was prepared to study the superficial veins on the dorsum of the hand among Jordanian students and staff of one of the major governmental medical colleges in Jordan, by using infrared illumination system. The obtained data was analyzed according to sex, sidedness, and handedness. Six locations of the most prominent dorsal metacarpal veins were identified. There was a significant relation between both females and males and the most prominent dorsal metacarpal vein (P=0.01). For the first time this study identified the most common location of the most prominent dorsal metacarpal vein in the fourth intermetacarpal space.

Snowballing Technique for High Flow Arteriovenous Fistula: A Technical Note

Riyadh Nasser Alokaili,Hesham Riyadh Alokaili,Mohammad F. Badran,Homoud Abdulaziz Aldahash,Shagran M. Binkhamis 대한신경중재치료의학회 2022 Neurointervention Vol.17 No.1

A novel endovascular technique to occlude high flow direct arteriovenous fistulae is presented, where the distal tip of the microcatheter acts as a nucleus that the operator can grow a plug from a liquid embolic agent. Its advantages (such as cost-saving and distal reachability), disadvantages (such as embolic material instability), and technique are discussed.