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Among the advantages of redundantly actuated mechanisms, one can mention the higher operational robustness, the feasibility of reduced power actuators and the load capacity increase in the mechanism. Focusing on such category of mechanism, the current work proposes a process for modeling and selecting the available actuation modes in accordance with adequate dynamic criteria. Here the modular modeling methodology is employed to formulate the dynamic equations for closed-loop redundantly actuated mechanisms of any topology that can operate even in the 2D- or 3D-spaces. Additionally, this general development is applied to generate dynamic models of the parallel mechanism 2 R R R + R R in the task space. Additionally, some simulations are conducted in order to compare the performance of the parallel mechanism when operating under distinct actuation modes, either keeping or switching between actuation modes during the motion cycle. The chosen metrics are the actuator torques and energy consumption. Moreover, other simulations aim to evaluate the capability of the actuated mechanism to overcome type-II singularities. Finally, this investigation also assesses the suitability of actuation mode indices for the motion planning of the parallel mechanism, which can be useful for control purposes.

In this research, thermal buckling and forced vibration characteristics of the imperfect composite cylindrical nanoshell reinforced with graphene nanoplatelets (GNP) in thermal environments are presented. Halpin–Tsai nanomechanical model is used to determine the material properties of each layer. The size-dependent effects of GNPRC nanoshell is analyzed using modified couple stress theory. For the first time, in the present study, porous functionally graded multilayer couple stress (FMCS) parameter which changes along the thickness is considered. The novelty of the current study is to consider the effects of porosity, GNPRC, FMCS and thermal environment on the resonance frequencies, thermal buckling and dynamic deflections of a nanoshell using FMCS parameter. The governing equations and boundary conditions are developed using Hamilton’s principle and solved by an analytical method. The results show that, porosity, GNP distribution pattern, modified couple stress parameter, length to radius ratio, mode number and the effect of thermal environment have an important role on the resonance frequencies, relative frequency change, thermal buckling, and dynamic deflections of the porous GNPRC cylindrical nanoshell using FMCS parameter. The results of current study can be useful in the field of materials science, micro-electro-mechanical systems and nano electromechanical systems such as microactuators and microsensors.

This research work presents another design of a multi-input multi-output (MIMO) antenna with dual wide operating bands at the millimeter-wave (MMW) region proposed for 5G applications. The design consists of two monopole elements with full size of 26 × 11 mm 2 . The two monopoles are designed to provide dual-band operation at the frequencies 27 GHz and 39 GHz. The mutual coupling between the two elements is studied and optimized to maximally reduce the effect of one element on the other. The S-parameters of the proposed MMW MIMO configuration are simulated using two software and measured using VNA. The results are well agreed with considerable shifting between the measured and the simulated, which can be due to the fabrication tolerance and cable losses. The radiation characteristics are investigated in terms of gain and efficiency. The proposed MIMO manifests acceptable gain that reaches 5 dBi and 5.7 dBi in the first and second bands, respectively, while the radiation efficiency reaches 99.5% and 98.6% over the first and the second bands, respectively. The MIMO performance is also studied where a very low envelope correlation of about 10 –4 is obtained and a diversity gain of about 10 dB over the two operating bands is also achieved. The comparison between simulation and measurement shows the possible potential of the proposed MIMO antenna that makes it feasible for MMW 5G applications.

The intention of the present work is to study the stability analysis of heat transfer enhancement occurring due to the influence of significant properties variation of fluids in the presence of thermal radiation with an aid of suspended hybrid nanofluids. The mathematical equations are converted into a pair of self-similarity equations by applying appropriate transformation. Runge Kutta Fehlberg 45th order method is applied to solve the reduced similarity equivalences numerically. The flow and energy transfer characteristics are studied for distinct values of important factors to obtain better perception of the problem. According to graphical results, heat transfer enhancement is higher for larger values of radiation parameter ( R ) and higher values of Prandtl number resulted in heat transfer reduction.

Microfluidics has been widely used in biological, chemical, medical and environmental fields for the precise control of liquid in micro/nanoscale. Various fabrication methods have been invented based on polymer materials in the past decade. Currently, under the circumstance of massive fabrication of microfluidic devices, injection molding is still the cheapest and fastest approaches. Injection molding products have been widely used in everyday life, however, the injection molding of polymer-based microfluidics has not been extensively investigated in the previous studies. In this study, we proposed a relatively comprehensive fabrication procedure for the injection molding of polymer microfluidic chips: the testing microfluidic chip with typical microfluidic components were designed, followed with mold design and fabrication; a single screw injection molding machine was used for the fabrication of PMMA-based microfluidic chips under different processing parameters; finally, another layer of polymer sheet was bonded to seal the microchannel and chip’s functionality was tested. The profile of the fabricated microchannels, as well as surface quality under difference injection molding parameters was also discussed in this study. This study is trying to provide a comprehensive injection molding approach for polymer-based microfluidics, the chip and injection mold design process, as well as the injection molding parameters, could have reference value for the future massive production of polymer microfluidic chips for biological and medical applications.

This article explores the influence of thermal radiation on the flow and heat transfer of single-walled carbon nanotubes over both a convergent and divergent channel. Flow is induced due to a Darcy–Forchheimer medium. Further, the heat transfer mechanism is analyzed in the presence of a thermal radiation process. Guided by some appropriate similarity transformations, the fundamental PDEs are converted into a self-similar system of coupled non-linear ODEs. The findings are obtained with the help of the Runge–Kutta-45-based shooting method. The roles of the Reynolds number, porosity parameter, inertia coefficient parameter, Prandtl number and radiation parameter are presented graphically. Results are displayed and show that the rate of heat transfer is higher in a divergent channel as compared to a convergent channel.

Background Posterior malleolus fracture fixation is recognised to prevent unnecessary syndesmotic stabilisation.1 British Orthopaedic Association Standards for Trauma and Orthopaedics (BOAST) guidelines mandate all tri-malleolar fractures require a computed tomography (CT) scan. Figure 2 (a) Clinical pictures showing a laminar spreader being utilised to expose posterior malleolus, and the posterior cortical reef is subperiosteally dissected and revealed. (b) Dis-impacting apex of posterior malleolus fracture undertaken with an osteotome. (c) Application of Kirschner wires (K-wire), followed by screw fixation - preferred technique is posterior-anterior screw fixation if feasible; in this case anterior-posterior was used for anaesthetic issues. Stringfellow TD, Walters ST, Nash W, Ahluwalia R. Posterior malleolus study group. management of posterior malleolus fractures: A multicentre cohort study in the United Kingdom.

Additive manufacturing or 3D printing is a rapidly developing technology that has revolutionized the manufacturing sector. In this paper, a review of various manufacturing methods is presented and selected features are compared. Some examples requiring features on the micron-scale are presented.

This article presents a free vibration analysis of size-dependent functionally graded rotating nanobeams with all surface effects considerations on the basis of the nonlocal continuum model. By using constitutive differential model of Eringen, the nonlocal elastic behavior is described which enables the present model to become effective in design and analysis of nanoactuators and nanosensors. The material for this work is a functionally graded which according to power law distribution, it is assumed that its bottom surface is aluminum and the top one is silicon. Taking attention to Euler–Bernoulli beam theory, the modeled nanobeam and its equations of motion are derived using Hamilton’s principle. Novillity of this work is considering the effects of rotation and surface effects in addition to considering various boundary conditions of the FG nanobeam. The generalized differential quadrature method is used to discretize the model and to get a numerical approximation of the equation of motion. The model is validated by comparing the benchmark results with the obtained ones. Then influence of surfaces effects, nonlocal parameter, angular velocity, volume fraction index and boundary conditions on natural frequency ratio of the rotating FG nanobeams are investigated.

With the rapid increase of urbanization and industrialization, particulate matter (PM2.5) concentration has increased significantly. PM2.5 profile forecasting has become one of the critical research areas in environmental control and protection. The early detection of PM2.5 as a pollutant is vital because PM2.5 has a significant impact on human health than other pollutants. This paper proposes a deep neuro-fuzzy prediction system (DNFPS) by amalgamating the deep learning and the fuzzy time series algorithm to forecast the PM2.5 concentration. The proposed predictive model consists of three phases; a data preprocessing algorithm to generate a high-quality dataset, a denoising autoencoder using fully convolutional neural networks (FCNNs) to extract the features from the pollutant time series profile as well as reduce the dimension of the time series dataset, and the type-2 fuzzy time series forecasting (FTSF) method to forecast PM2.5 concentration. The butterfly optimization algorithm (BOA) is integrated with the type-2 FTSF method to improve the prediction accuracy of the proposed method. FTSF-BOA is implemented to fine-tune the length of type-2 fuzzy intervals. Experiments employing Sydney data sets to analyze the performance of DNFPS. DNFPS shows that the proposed model achieves an excellent performance than other standard baseline models. It has lower computational time (training time) than the other traditional baseline deep learning models.