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The purpose of this paper is to design and simulate a piezoelectric micropump using microelectromechanical systems technology for drug delivery applications.

Two piezoelectric actuators are used to actuate and bend the diaphragms in the proposed structure. In this micropump, the liquid flow is rectified by two silicon check valves.

The use of two piezoelectric transducer (PZT) actuators in the parallel mod not only reduces dead volume but also increases stroke volume as well. In addition to increasing the flow rate, this phenomenon enhances the operation of the micropump to have self-priming as smoothly as possible.

This actuating method results in a 22% increase in flow rate and compression ratio, as well as a 15% reduction in function voltage. The fluid-solid interaction is simulated using COMSOL Multiphysics 5.3a.

Wireless sensor networks (WSN), as a solution for buried water pipe monitoring, face a new set of challenges compared to traditional application for above-ground infrastructure monitoring. One of the main challenges for underground WSN deployment is the limited range (less than 3 m) at which reliable wireless underground communication can be achieved using radio signal propagation through the soil. To overcome this challenge, the purpose of this paper is to investigate a new approach for wireless underground communication using acoustic signal propagation along a buried water pipe.

An acoustic communication system was developed based on the requirements of low cost (tens of pounds at most), low power supply capacity (in the order of 1 W-h) and miniature (centimetre scale) size for a wireless communication node. The developed system was further tested along a buried steel pipe in poorly graded SAND and a buried medium density polyethylene (MDPE) pipe in well graded SAND.

With predicted acoustic attenuation of 1.3 dB/m and 2.1 dB/m along the buried steel and MDPE pipes, respectively, reliable acoustic communication is possible up to 17 m for the buried steel pipe and 11 m for the buried MDPE pipe.

Although an important first step, more research is needed to validate the acoustic communication system along a wider water distribution pipe network.

This paper shows the possibility of achieving reliable wireless underground communication along a buried water pipe (especially non-metallic material ones) using low-frequency acoustic propagation along the pipe wall.

The purpose of this study is to clarify the mechanism of ambient and transient temperature effects on piezoelectric pressure sensors, and to propose corresponding compensation measures. The temperature of the explosion field has a significant influence on the piezoelectric sensor used to measure the shock wave pressure. For accurate shock wave pressure measurement, based on the actual piezoelectric pressure sensors used in the explosion field, the effects of ambient and transient temperatures on the sensor should be studied.

The compensation method of the ambient temperature is discussed according to the sensor size and material. The theoretical analysis method of the transient temperature is proposed. For the transient temperature conduction problem of the sensor, the finite element simulation method of structure-temperature coupling is used to solve the temperature distribution of the sensor and the change in the contact force on the quartz crystal surface under the step and triangle temperatures. The simulation results are highly consistent with the theory.

Based on the analysis results, a transient temperature control method is proposed, in which 0.5 mm thick lubricating silicone grease is applied to the sensor diaphragm, and 0.2 mm thick fiberglass cloth is wrapped around the sensor side. Simulation experiments are carried out to verify the feasibility of the control method, and the results show that the control method effectively suppresses the output of the thermal parasitic.

The above thermal protection methods can effectively improve the measurement accuracy of shock wave pressure and provide technical support for the evaluation of the power of explosion damage.

The purpose of this paper is to develop an organized structure for damage detection of a cracked cantilever beam using finite element method and experimental method technique.

Due to presence of cracks the dynamic characteristics of structure change. The change in dynamic behavior has been used as one of the criteria of fault diagnosis for structures. Major characteristics of the structure which undergo change due to presence of crack are: natural frequencies, the amplitude responses due to vibration and the mode shapes. Therefore, an attempt has been made to formulate a smart technique for minimizing the amplitude of vibration for crack cantilever beam structures. In the analysis both single and double cracks are taken into account.

The results of the active vibration control experiments proved that piezoelectric sensor/actuator pair is an effective sensor and actuator configuration for active vibration control to reduce the amplitude of vibration for closed-loop system.

It is necessary that structures must safely work during its service life, but damages initiate a breakdown period on the structures which directly affect the industrial growth. It is a recognized fact that dynamic behavior of structures changes due to presence of crack. It has been observed that the presence of cracks in structures or in machine members leads to operational problem as well as premature failure.

Bearings are critical components used to support loads and facilitate motion for rotating and sliding parts of the machinery. Bearing malfunctions can cause catastrophic failures. Hence, failure analysis and endeavors to improve bearing performance are essential discussions for worldwide designers, manufacturers and end users of vital machinery. This study aims to investigate a type of roller bearing from the railway industry with premature failures. The task arises because locomotives’ maintenance and service life quality are vital to railway operations while providing transportation services for the nation. To assist in maintaining the designated locomotives, the present study scrutinizes the causes of failure of heavy-duty roller bearings from locomotive bogie axleboxes.

It is intended to inspect this bearing service life and statistically scrutinize its design parameters to reveal the failures’ shortcomings and origins. The significant measures include examinations of their failures’ primary and vital factors by comparing them with a real-life service history of 16 roller bearings of the same type. The bearings come from the axleboxes of a locomotive bogie with an axle load of 20 tons. The bearing loads are estimated using the EN13104 standard document and confirmed by the finite element method using ABAQUS engineering software. To validate the finite element modeling results, the bearings’ stress analysis is performed using the Hertzian contact theory that demonstrated perfect conformity. The said methods are also used to search for the areas susceptible to failures in these bearings. With the inclusion and exploitation of the bearing maintenance conditions and the logbook recordings of the locomotives for the past seven years, the critical cause for this type of bearing’s failures is surveyed and discussed.

With the inclusion and exploitation of the bearing maintenance conditions and the logbook recordings of the locomotives for the past seven years, the critical cause for this type of bearing’s failures is surveyed and discussed. As a crucial result, it is found that deprived maintenance and inadequate lubrication are the root causes of the loss of the selected bearings.

For the designated locomotives, the origins of the heavy-duty roller bearing failures and its design shortcomings are revealed by examining and comparing them with a real-life service history of many of the same types of bearings. The novelty of the research is in using the combination of the methods mentioned above and its decent outcome.

The main objective of this paper is to illustrate an analytical view of different methods of 3D bioprinting, variations, formulations and characteristics of biomaterials. This review also aims to discover all the areas of applications and scopes of further improvement of 3D bioprinters in this era of the Fourth Industrial Revolution.

This paper reviewed a number of papers that carried evaluations of different 3D bioprinting methods with different biomaterials, using different pumps to print 3D scaffolds, living cells, tissue and organs. All the papers and articles are collected from different journals and conference papers from 2014 to 2022.

This paper briefly explains how the concept of a 3D bioprinter was developed from a 3D printer and how it affects the biomedical field and helps to recover the lack of organ donors. It also gives a clear explanation of three basic processes and different strategies of these processes and the criteria of biomaterial selection. This paper gives insights into how 3D bioprinters can be assisted with machine learning to increase their scope of application.

The chosen research approach may limit the generalizability of the research findings. As a result, researchers are encouraged to test the proposed hypotheses further.

This paper includes implications for developing 3D bioprinters, developing biomaterials and increasing the printability of 3D bioprinters.

This paper addresses an identified need by investigating how to enable 3D bioprinting performance.

In this paper, it can be seen from AFM images of the as-deposited ZnO and CZO films, and the particle size and shape are not clear, while by increasing annealing temperature, they become distinguishable. By increasing temperature to 600°C, ZnO and CZO, CAZO and aluminum-doped zinc oxide (AZO) films particles became almost spherical. Due to high content of Cu in CZO target, and of Al in AZO target which was 5% weight ratio, doping plays a great role in the subject. Therefore, the annealing processing strongly affect the size and the shape of nanoparticles.

In this paper, the authors tried to study, in detail, nobel optical characterizations of ZnO films doped by transition metals in different annealing temperature. The authors found that the values of skin depth, optical density, electron–phonon interaction, steepness parameter, band tail width, direct and indirect carriers transitions and the dissipation factor, free carriers density and roughness of films affect the optical properties, especially the optical absorptions of ZnO films doped by transition metals. Also these properties were affected by annealing temperatures. The authors also found that topography characterizations strongly were affected by these parameters.

The CZO films have maximum value of coordination number ß, with considering N_C = 4, Z_a = 2, N_e = 8. The CZO films annealed at 500 °C have maximum value of optical density. The as-deposited CAZO films have maximum value of steepness parameters in about of 0.13 eV. The as-deposited AZO films have maximum value of dispersion energy Ed in about of 5.75 eV. Optical gap and disordering energy plots of films can be fitted by linear relationships E_g = 0.49 + 0.2 EU and E_g = 0.52 + 0.5 EU, respectively.

With considering N_c = 4, Z_a = 2, N_e = 8 for ZnO films, coordination number ß has maximum value of 0.198. CZO nanocomposites films annealed at 500°C have maximum value of optical density. Different linear fitting of ln (α) for films were obtained as y = A_x + B where 5<A < 17 and 5<B < 12. As-deposited CAZO nanocomposites films have minimum value of electron phonon interaction in about of 4.91 eV. Optical gap and disordering energy plots can be fitted by linear relationships E_g = 0.49 + 0.2 EU and E_g = 0.52 + 0.5 EU for as-deposited films and films annealed at 500°C, respectively. Steepness parameters of as-deposited CAZO nanocomposites films have maximum value of 0.13 eV. Dispersion energy Ed for as-deposited AZO nanocomposites films has maximum value of 5.75 eV.

This study aims to simulate gust effects on the aeroelastic behavior of a flexible aircraft. The dynamic response of the system for different discreet gust excitations is obtained using numerical simulations.

Coupled dynamics, including rigid and flexible body coordinates, are considered for modeling the dynamic behavior of the aircraft. Wing is considered flexible and other parts are considered rigid. Wing is modeled with nonlinear Euler Bernoulli beam. Moreover, unsteady aerodynamics based on the Wagner function are used for aerodynamic loading, and the results are compared with those of quasi-steady aerodynamics.

Von Kármán continuous gust is applied to this aircraft. In addition, the discrete “1- cosine” gust with different gust lengths is applied to the aircraft, and the maximum and minimum accelerations are computed. It is shown that the nonlinear modeling of the system represents the actual behavior and causes limit cycle oscillation phenomena.

This methodology can yield a relatively simple dynamic model for high aspect ratio aircrafts to provide insights into the vehicles’ dynamics, which can be available early in the design cycle.

This paper presents the experimental and numerical results of the bending properties of low-height prestressed T-beams. The purpose is to study the bearing capacity, failure state and strain distribution of low-height prestressed T-beams.

First, two 13 m-long full-size test beams were fabricated with different positions of prestressed steel bundles in the span. The load–deflection curves and failure patterns of each test beam were obtained through static load tests. Secondly, the test data were used to validate the finite element model developed to simulate the flexural behavior of low-height prestressed T-beams. Finally, the influence of different parameters (the number of prestressed steel bundles, initial prestress and concrete strength grade) on the flexural performance of the test beams is studied by using a finite element model.

The test results show that when the distance of the prestressed steel beam from the bottom height of the test beam increases from 40 to 120 mm, the cracking load of the test beam decreases from 550.00 to 450.00 kN, reducing by 18.18%, and the ultimate load decreases from 1338.15 to 1227.66 kN, reducing by 8.26%, therefore, the increase of the height of the prestressed steel beam reduces the bearing capacity of the test beam. The numerical simulation results show that when the number of steel bundles increases from 2 to 9, the cracking load increases by 183.60%, the yield load increases by 117.71% and the ultimate load increases by 132.95%. Therefore, the increase in the number of prestressed steel bundles can increase the cracking load, yield load and ultimate load of the test beam. When the initial prestress is from 695 to 1,395 MPa, the cracking load increases by 69.20%, the yield load of the bottom reinforcement increases by 31.61% and the ultimate load increases by 3.97%. Therefore, increasing the initial prestress can increase the cracking load and yield load of the test beam, but it has little effect on the ultimate load. The strength grade of concrete increases from C30 to C80, the cracking load is about 455.00 kN, the yield load is about 850.00 kN and the ultimate load is increased by 4.90%. Therefore, the improvement in concrete strength grade has little influence on the bearing capacity of the test beam.

Based on the experimental study, the bearing capacity of low-height prestressed T-beams with different prestressed steel beam heights is calculated by finite element simulation, and the influence of different parameters on the bearing capacity is discussed. This method not only ensures the accuracy of bearing capacity assessment, but also does not require a large number of samples and has a certain economy. The study of prestressed low-height T-beams is of great significance for understanding the principle and application of prestressed technology. Research on the mechanical behavior and performance of low-height prestressed T beams can provide a scientific basis and technical support for the design and construction of prestressed concrete structures. In addition, the study of prestressed low-height T-beams can also provide a reference for the optimization design and construction of other structural types.

The purpose of this study is to achieve lower and lower temperature as infrared sensors works faster and better used for space application. For getting good quality images from space, the infrared sensors are need to keep in cryogenic temperature. Cooling to cryogenic temperatures is necessary for space-borne sensors used for space applications. Infrared sensors work faster or better at lower temperatures. It is the need for time to achieve lower and lower temperatures.

This study presents the investigation of the critical Stirling cryocooler parameters that influence the cold end temperature. In the paper, the design approach, the dimensions gained through thermal analysis, experimental procedure and testing results are discussed.

The effect of parameters such as multilayer insulation, helium gas charging pressure, compressor input voltage and cooling load was investigated. The performance of gold-plated and aluminized multilayer insulation is checked. The tests were done with multilayer insulation covering inside and outside the Perspex cover.

By using aluminized multilayer insulation inside and outside the Perspex cover, the improvement of 16 K in cool-down temperature was achieved. The cryocooler is charged with helium gas. The pressure varies between 14 and 18 bar. The optimum cooling is obtained for 17 bar gas pressure. The piston stroke increased as the compressor voltage increased, resulting in total helium gas compression. The optimum cool-down temperature was attained at 85 V.

The cryocooler is designed to achieve the cool-down temperature of 2 W cooling load at 100 K. The lowest cool-down temperature recorded was 105 K at a 2 W cooling load. Multilayer insulation is the major item that keeps the thermal radiation from the sun from reaching the copper tip.