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This article reviews the most recent researches about the use of nondestructive air-coupled ultrasound in food industries. In the field of food quality assessment, in several researches detection of foreign bodies, and measurement certain parameters of interest, such as the amount of a certain additives are investigated. Also in other research a rapid, non-contact and non-destructive air-coupled ultrasound technique has shown itself to be a feasible method for investigating the quality of milk-based beverages, and possibly other food products. Air-coupled ultrasound can be used in on-line situations for measuring food materials such as chocolate and cheese. It is also capable of performing nondestructive measurements on moving sealed metal cans containing food, and is able to detect foreign bodies with the top removed, as encountered before sealing. Air-coupled ultrasound has been used to perform measurements on liquids and starch-based materials, within containers similar to those used in the food industry. Ultrasonic pulse-compression (UPC) is then applied to increase the sensitivity of signals transmitted through the containers. It will be demonstrated that various nondestructive non-contact measurements are possible, including the detection of variations in consistency within starch-based liquids within a microwaveable food container, measuring of beverage level in polymer-based bottles, and the tomographic imaging of likewise containers to detect foreign objects.

Ultrasonic transducers are the most important part of an ultrasonic testing system which significantly affect the precision and accuracy of the measurements. Piezoelectric transducers are the most common ultrasonic transducers which include three major components: the piezoelectric disk, backing material, and matching layer. The optimal combination of these three components is traditionally done by trial and error. Analytical models used for this purpose have their own pros and cons and are not capable of predicting the complete performance of the transducer. Finite element modeling is an alternative method that can be used for designing ultrasonic transducers. This paper presents a finite element model for a 4 MHz ultrasonic transducer excited by a spike signal in pulse-echo mode. The model considers an ultrasonic transducer composed of a piezoelectric disk, a matching layer, and a backing material. The main advantage of this model in comparison to earlier models is the incorporation of piezoelectric elements instead of mimicking the piezoelectric effect by applying forces or displacements. In the developed model, the input is an electrical signal and the output is an electrical voltage. This makes this model very similar to the way a real ultrasonic transducer operates. The simulation results are compared with results obtained from experiments and very good agreement is observed.

Power pylon networks are vital part of each country and they need regular inspection. The inspection operation usually is done by visual test (VT). This process takes time and energy and it may have several threats for inspector, so robots can do it. We made an unmanned aerial vehicle (UAV) which it can fly and carry necessary instruments for VT. This robot can be controlled remotely by operators. In this paper, convenient approaches for inspection and advantages and disadvantages of them were explained. Also the current pylon and power transmit equipment was introduced. After that, the new approach for inspection was presented. In this solution, the unmanned aerial vehicle (UAV) is used for monitoring and inspection of pylons. Then design and implementation steps are presented. These steps contain the mechanical, electrical and programing parts. In the next part, an inspection operation which was done by the robot is reported. Finally the ordinary inspection and robot inspection are compared together in terms of time, money, threats and quickness.

Damage detection capabilities in pipes are under influence of attenuation factors as high values of attenuation and large variability with pipe condition result in unpredictable guided wave test (GWT) range. In this paper, an accurate finite element model (FEM) is prepared by applying pigging data of a gas pipeline for simulating existing local and pitting corrosion areas including material properties and thickness loss. The scanned data can be processed with reduction in radius against circumference and axial direction. Importing pigging datasets to ABAQUS software is carried out by use of Python scripting in order to automatic assignment of material properties for each single element of the model. Finally, the effects of attenuation factors such as scattering due to corrosion damages, material damping of coating and leakage into surrounding soil media are investigated through exciting longitudinal L(0,2) and torsional T(0,1) modes. The attenuation values are found to be larger for T(0,1) mode in all of the investigated cases.

Damage detection techniques are one of the most active fields of research that attracted a lot of interest in the recent years. The imperialist competitive algorithm was developed over the last few years as a meta-heuristic algorithm using socio-politically motivated optimization strategy to solve optimization problems and is employed to solve the damage detection problem in this paper. Three different objective functions are selected and calculated using the first few modal responses: 1) the norm of difference of analytical and real damaged structure, 2) the multiple damage location assurance criterion (MDLAC) value using the natural frequencies, 3) minimizing the error value calculated based on the eigen-equation. This strategy is numerically applied to a cantilever beam and a steel frame for offshore application. The results are compared with other methods and demonstrate the efficiency and high speed of the proposed algorithm in identifying the damage locations and extents.

During the production of safety relevant pipes, tanks or high pressure vessels a comprehensive quality control is mandatory. Especially welding lines have to be inspected complying to highest international quality standards. A failure can lead to severe consequences and liability charges for manufacturers. Modern Digital Radiography helps to achieve the quality control and archiving requirements while providing cost reduction through a high degree of automation. The past approach was a highly manual and time consuming analogue approach using X-ray film. This article explains the basic concept of digital X-ray technology and discusses several integration concepts. To support the justification process, a comprehensive techno-commercial analysis based on inspection quality, throughput and return of invest is provided. To ensure relevance a broad variety of examples, case studies and inspection standards is referenced.

A three-stage method is presented using Basis Pursuit (BP) and the Particle Swarm Optimization (PSO) technique. Recently, optimization techniques have been employed to solve the damage detection problems. The proposed method needs the first few modal responses of structure. First, a system of equations which relates the damage extent to the structural responses is solved using the BP method. The results of this stage are used as the initial population of PSO algorithm. To reduce the search space of PSO, a micro search operator is embedded in the algorithm to eliminate low damage values. To overcome the noise present in structural responses, a method known as Basis Pursuit De-Noising (BPDN) is also used. The efficiency of the proposed method is investigated by numerical models of a pipe rack and a portal plane frame. The simulation results demonstrate the accuracy and efficiency of the proposed method in detecting multiple damage cases and exhibit its robustness regarding noise.

Due to its earthquake resistant properties, most building structures are constructed with reinforced concrete on a steel structure. As the temperature of steel increases especially during a fire, it will reduce the strength of a structure. Since the properties of steel, such as the Young