Journal of Engineering and Thermal Sciences
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Source localization in reverberation environment based on improved equivalent sound source near-field acoustic holography algorithm
Get PDFThe compressive-equivalent source method near-field acoustic holography (C-ESM) is disturbed by reverberation in the enclosed space such as room and cabin, which leads to large reconstruction error and disturbs the judgment of sound source position. In order to solve this problem, an improved C-ESM algorithm based on room impulse response (RIR) is proposed to filter out reverberation interference in this paper. Different from the original equivalent source method, the improved algorithm constructs the transfer function through the room impulse response to establish the relationship between the equivalent source and the sound pressure on any plane in space, and the sparse signal reconstruction method of the compressive sensing technology is used to obtain the strength of the equivalent source. Then the transfer function to any plane of space is established according to the free field Greenβs function, to eliminate the interference of reverberation and improve the effect of sound source location. The accuracy and effectiveness of the improved method are verified by preliminary numerical simulation. And the results show that compared with the original algorithm, this method has obvious advantages in sound source localization in a reverberant field
Qualitative assessment of the Upper limb of child with cerebral palsy
Get PDFThe management of the upper limb (MS) of the child with cerebral palsy (CP) is long past that of walking; many factors make it difficult to study the MS of the child PC: The variability of involvement (spasticity, dystonia) with, unlike the lower limb, the significant impact of associated disorders (sensory, cognitive) for functional use of the upper limb. The great diversity of tasks performed by the upper limb in contrast to the lower limb (cyclic activity of walking) which requires many assessment tools with standardized and age-appropriate tasks, for the multiple treatment goals. But for over fifteen years, with the advancement of research on brain plasticity, the development of new tools and access to certain therapeutics this care has taken a more important place and especially much earlier in the arsenal therapeutic. So we must emphasize the importance of choosing valuable tools for evaluation. .car if the used tests are not relevant, the relevance of the therapeutic action that will follow becomes her also questionable, Moreover, this means also that the therapist has some knowledge of possible therapeutics in order to able to inform his patient and refer him to appropriate stakeholders
Numerical analysis of temperature distribution in sliding contacts of pin on disc model
Get PDFPin on disc is a tribosystem confirming to ASTM G99, is employed in this work. It consists of deformable cylindrical disc and rigid pin with friction. Coating of Inconel 712 is added on stainless steel disc and pin is made of SiC3. The FEM software ANSYS R19.1 is employed for simulation of temperature distribution produced due to friction between pin on disc. Stress distribution is calculated from result produced between pin and disc interface due to applied contact load on pin. The governing equation is mentioned in introduction section. Result showing as contact load on pin increases maximum principle stress is increases. Temperature rises in direct proportion with sliding distance and time. Simulation result validates and confirmed with experimental results
Identification and location of ship pipeline leakage based on VMD
Get PDFPipeline plays an important role in various systems of the ship. However, due to the harsh environment, leakage often occurs in ship pipeline. This paper proposes a method to identity and locate the pipeline leakage. Using the variational mode decomposition (VMD) algorithm, the vibration signal is decomposed into band-limited intrinsic mode functions (BIMFs). The effective BIMFs are then selected by the correlation coefficient. Center frequency and energy value of the effective BIMFs are extracted as feature vector. Radial Basis Function (RBF) neural network is then used as a tool to identify and locate the leakage. The proposed method is finally verified by experiments
A multi-fault diagnosis method for piston pump in construction machinery based on information fusion and PSO-SVM
Get PDFPiston pumps are key components in construction machinery, the failure of which may cause long delay of the construction work and even lead to serious accident. Because construction machines are exposed to poor working conditions, multiple faults of piston pumps are most likely to occur simultaneously. When multiple faults occur together, it is difficult to detect. A multi-fault diagnosis method for piston pump based on information fusion and PSO-SVM is proposed in this thesis. Information fusion is used as fault feature extraction and PSO-SVM is applied as the fault mode classifier. According to the method, vibration signal and pressure signal of piston pump in normal state, single fault state and multi-fault state are collected at first. Then the empirical mode decomposition (EMD) is used to decompose vibration signals into different frequency band and energy features are extracted. These energy features extracted from vibration signals and time-domain features extracted from pressure signal are information fused at the feature layer and constitute the eigenvectors. Finally, these eigenvectors are put into support vector machine (SVM) and the working conditions of piston pump were classified. Particle swarm optimization (PSO) is applied to optimize two parameters of SVM. The experimental results show that the recognition accuracy of the normal state, three single failure modes and multi-fault modes are 98.3Β %, 97.6Β % and 94Β % respectively. These recognition accuracies are higher than which using vibration signal or pressure signal alone. So, the proposed method can not only identify the single fault, but also effectively identify the multi-fault of piston pump
Economic benefit analysis of low-level high vacuum compaction method from the perspective of low carbon
Get PDFIn order to discuss the superiorities of High Vacuum Drubbing Means (HVDM) in soft foundation treatment of roads, this paper takes the soft foundation treatment project of Wucheng Road in Wuwei County of Wanjiang City Belt in China as an example. By comparing and analyzing the economic benefit differences between HVDM method and traditional powder injection pile method in soft soil foundation treatment, the following conclusions are drawn: Low-level high-vacuum compaction method soft base processing method is better than traditional powder-jet pile method in soft foundation treatment. The method can better reduce the consumption of raw materials such as cement and stone, avoid the pollution of the social environment caused by cement production, shorten the construction period by about 50Β % and save the direct labor cost. Compared with the traditional powder-sprayed pile method, total cost of the project can be saved by more than 30Β % and the construction quality is controllable. The construction process is green and its social and economic benefits are remarkable
Vibration suppression effects on rotating wind turbine blade using a particle damping method
Get PDFDue to the vibration of the wind turbine blade, the rate of electricity generation gets reduced. In this research, the focus is on reduction of wind turbine blade vibration. The important point is that in the attempt of vibration suppression, a new method of damping named particle damping has been tried. The novelty of this study is that this method is adopted for the first time in wind turbine blade for rotating condition. In this method, containers filled with spherical particles are mounted at four different positions on each blade alternatively. Taking tests at different rpm and container positions gives a different vibration suppression effect as compared to without damping and finding optimum positions for mounting of damper
Influence of damping coefficient into engine rubber mounting system on vehicle ride comfort
Get PDFThis study presents a method to improve vehicle ride comfort using additional damping coefficient values for an internal combustion engine (ICE) rubber mounting system. To analyze the effect of the adding damping coefficient values into the rubber mounting system on vehicle ride comfort, a full-vehicle vibration model with 10 degrees of freedom is established under the combination of road surface roughness and ICE excitations. The damping coefficient values are added into ICE rubber mounting system which are respectively analyzed and evaluated according to the international standard ISO 2631-1 (1997). The study results do not only evaluate the influence of the adding damping coefficients on vehicle ride comfort but also suggest the optimal design solution for ICE mounting system to improve vehicle ride comfort
Dynamic load effect on the transportation safety of tank containers as part of combined trains on railway ferries
Get PDFMaintaining the leading position of railway transport in the international transportation market led to the creation of its combined interaction with other modes of transport. In countries that have access to international traffic through the sea, rail-ferry services have been developed. At the initial stage of functioning of this symbiosis, only freight and passenger cars were transported by sea. At the moment, it has become possible to follow container trains on railway ferries by sea. An example would be the international Silk Road corridor, which connects Ukraine with China. Important components of this corridor are two rail-ferry routes through the waters of the Black and Caspian Seas
Experimental study of self-sustainable hybrid solar photovoltaic cleaning mechanism coupled with water distillation unit
Get PDFIn the present research work a novel self-sustainable hybrid solar photovoltaic cleaning mechanism coupled with water distillation unit has been proposed. The experiments were conducted on the PV (photovoltaic) modules at Bennett University, Greater Noida A-block terrace from 7th to 13th October, 2019. Post installation, the average efficiencies of the solar PV module system with and without cleaning were compared to obtain a hike by 1.34Β %. The water used for cleaning was recycled using a single slope basin type solar still which indicated a working efficiency of 67.94 %. On an average the solar still yielded 5.3 Litres of pure water every day during the experiment with a TDS (total dissolved solids) level of 104 ppm