It is essential to maintain the aerodynamic performance of the air-conditioning system meanwhile reducing the noises (including aerodynamic, broadband, and discrete noises), determining the consumer's comfort level. In this work, depending on the coupling of the wavy leading-edge and the seagull airfoil, the aeroacoustics noise and aerodynamic performance of the impellers with the coupling bionic blade were investigated in detail. The results indicate the aerodynamic performance was improved by the coupling bionic optimization. Moreover, the total pressure efficiency (η) of the coupling bionic blade increases by 2. 28% in comparison to the original blade. Furthermore, A smaller static differential pressure is observed between the suction and pressure sides, and vortices and backflows from the pressure side to the suction side are hampered, causing a reduction in turbulence noise. Additionally, the broadband noise of the coupling bionic blade decreases by 3. 59 dB. Besides, the coupling bionic blade improves the directivity of the sound pressure level, especially in the middle-frequency and low-frequency region, resulting in a decrease of 7. 9 dB for the aeroacoustics noise of the coupling bionic blade. What's more, the modal analysis demonstrates the security of the designed coupling bionic blade. In generally, this work provides some inspiration to design axial flow fans with excellent aerodynamic performance and low-noise characteristics.

In this paper, a new method for extending and relaxing the noise-coupling (NC) technique is proposed to enhance the noise-shaping order without adding the number of integrators. The noise-shaping order of the introduced ∑∆ modulator whit applying a second-order noise-coupling technique is enhanced and its performance with optimizing the noise transfer function (NTF) zeros is improved. Also, by removing the analog adder at feedforward path and transferring it to a new feedback branch before the last integrator and adding second-order NC path can be decreased the input voltage swing to the quantizer. Thus, by improving the modulator resolution, power consumption can be reduced. Mathematical analyses and behavioural simulation results confirm the effectiveness of the new NC method. To examine its performance, a 2nd-order single loop ΣΔ modulator was designed. The new noise-coupling method is used to achieve the three-order noise shaping to increase the resolution with low complexity and low-power. The results show an outstanding improvement in signal-to-noise and distortion ratio (SNDR) compared to the conventional structure.

Generally, there are different challenges in traditional approaches to aircraft design, resulting in a decrease in the efficiency of the design process. For instance, decisions made at the conceptual design phase are based on limited knowledge about design, while these decisions can significantly decrease the design freedom in further design steps. In addition, the decision in the conceptual design phase constituted as high as 80% of the life-cycle costs. Furthermore, in the conceptual design phase, because of their critical issues in achieving performance requirements, more attention has been given to aerodynamics and propulsion disciplines, while other disciplines are evaluated only later throughout the design process. However, in the last decades, new requirements such as environment-friendliness, considering global warming, reducing energy consumption, reusing, recycling, and remanufacturing have been added to aircraft design criteria. These changes in design requirements have led to the development of different kinds of Functional Requirements (FRs) and disciplines and, consequently, increased coupling and iterative cycles. These issues have increased the complexity of the aircraft conceptual design process compared to the past. Consequently, in the last decades, many researchers and designers have tried to address these challenges. In this regard, various design methodologies such as multidisciplinary design optimization and knowledge-based engineering were developed. These approaches could support the evolutionary improvement of current product designs or the study of the novel complex product or could reduce the coupling between various FRs and Design Parameters (DPs). In this research, designers tried to use the Axiomatic Design (AD) approach to identify and reduce coupling between different FRs, resulting in less repetitive activities and design iteration in the design process. The authors also developed an algorithm based on the AD method to improve the conceptual aircraft design. The results obtained in this study indicate the high efficiency of this method in reducing the coupling between the FRs defined for the aircraft as well as in reducing repetitive activities, thus optimizing the time and the cost of the aircraft design process.

Vibrations can have favorable or undesirable effects on systems. The discomfort of the vehicles as a result of moving on rough roads is an example of the adverse effects of vibrations. A variety of dampers are used to prevent these damages. MR is one of the advanced technologies in the field of suspension systems. There is a lot of research today to increase the damping force, reduce construction costs, and design and simulate a damper with ease of construction, which indicates the necessity of a progressive research. In this paper, after the theoretical reviews the equations governing the mechanical model (by the Bingham plastic model), the electromagnetic field (by the Maxwell and Amp law) and the flow field (by the Naviers-Stokes equation) Until a double-rod Damper, which is an exquisite example of these dampers, is designed and simulated through the Camsol software through a multiphysics coupling (fluid-solid-magnet) interaction and then analyze the results. Also, the sample designed, unlike previous examples of these dampers, does not require a gas compensatory chamber. The information obtained from the simulation results showed that due to the requirements of a light car aid that requires a damping force of more than 1000 Nm, the damper is a suitable semi -active device and can produce the minimum amount of the required in the required intense force. Transportation and other areas, such as the suspension of light cars, should be used and improve the comfort and increase the quality of the vehicle.

nature has developed materials, objects and processes that function from the macro scale to the nano scale. The understanding of the functions provided by objects and processes found in nature can guide us to imitate and produce appropriate architectural forms. Biomimicry is a science that derives inspiration for solutions to human problems through the study of natural designs, systems and processes. In consideration of the global trend of environmental protection, the disciplinary focal point also tends to work on the issue of sustainable development. However, though the researches of sustainable design and green design have been increased, the subjects of these researches yet were mostly undertaken from the aspects of material, structure and form; and the application of ‘bionics’ to architecture or design seems to be treated as a new, contemporary idea. The attraction of Biomimetics for architects is that it raises the prospect of closer integration of form, material, construction, process and function with regard to a holistic building design. It promises to yield new means by which buildings respond to, and interact with, their users means more subtle and more satisfying than present mechanical systems. The appeal of biomimetics is not only from a method for acquiring abstract design ideas from nature but also from the manner in which nature utilizes those ideas. Nature has adapted the plans from which it derives organisms to be based on a relatively simple set of instructions. Common to both natural and man made environments is the issue of cost. There is always an issue of how much an object, structure, or organism will cost to design, manufacture, construct, maintain and ultimately recycle. In an architectural sense this can be reduced to a monetary cost where often times the lowest tender wins. In the natural world the cost is energy, where competition for available resources favors the organism that can survive and grow with the least amount of required materials and energy expenditure. This project selects nature as model in the design of the auditorium acoustics. Bivalves are often the most common seashells that wash up on large sandy beaches or in sheltered lagoons. The goal of this paper was to design a biomimetic multipurpose auditorium inspired by seashells that would have appropriate acoustics for a variety of purposes, specifically conferences, lectures, movies and orchestra. The objective of this research is to investigate the relationship between room shapes and speech intelligibility in auditorium acoustics. Three different auditoriums shapes; seashell, fan and rectangular with the same RT and volume were modeled in Rhino and the models were then exported to EASE acoustic analysis software. The comparison of STI values estimated from EASE indicated that the seashell shaped room had the highest mean STI values. The comparison of C50 and center time (ts) values show that the shell shaped auditorium has the best values. In addition, musical sound qualities were investigated using clarity index (C80) and Ts acoustical parameters. Appropriate values were found in all of the rooms.

Intracytoplasmic sperm injection (ICSI) is one of the most successful techniques of Assisted Reproductive Technology (ART) and is mostly in use for the treatment of infertility with male factors. In this method, before injecting sperm into the intracytoplasmic of the oocyte, cumulus cells around the oocyte must be stripped to facilitate the injection process. To achieve this, both enzymatic and mechanical methods are used in embryological laboratories for denudation, which has major deficiencies, including the possibility of damaging the oocyte prior to the injection process. In this research, a microfluidic-based device is introduced for the separation of cumulus cells around the oocyte with minimum manual operations. The results prove high efficiency, and non-destructive denudation of the oocyte with the reduced amount of culture medium leads to the low-cost preparation process of oocytes. The process can also be integrated with ICSI chips under development and will be reported shortly.

Inspired by the challenging and nimble flight dynamics of flying insects and birds, this research investigates bionic propulsion technology to develop an improved flapping wing micro air vehicle (FWMAV) design. Following the bionic formula, a prototype is preliminarily designed to achieve multi-attitude flight. Then, kinematic modeling is employed for further data analysis. A meshless particle hydrodynamics method is adopted to explore an optimized flapping driving mechanism and understand the influence of the flapping frequency, flapping amplitude, and quick-return characteristics of one side of the symmetrical mechanism on aerodynamic performance. Based on the aerodynamic model, force measurement experiments are developed to verify simulation availability and investigate the importance of wing flexibility. The numerical analysis results demonstrate that the average lift is approximately proportional to the flapping frequency, flapping-wing amplitude, and quick-return characteristics. Further optimization is conducted to find the best design parameters setting because of the complicated coupling relationship between the flapping wing amplitude and quick-return characteristics. Moreover, the optimized wing property supports high aerodynamic performance via experimental analysis in hovering flight.