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Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions
No full textCavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and phenol and its derivatives in a basic model effluent using hydrodynamic and acoustic cavitation combined with external oxidants, i.e., hydrogen peroxide, ozone and peroxone. The studies revealed that the combination of cavitation with additional oxidants allows 100% oxidation of the investigated model compounds. However, individual treatments differed with respect to the rate of degradation. Hydrodynamic cavitation aided by peroxone was found to be the most effective treatment (100% oxidation of all the investigated compounds in 60 min). When using hydrodynamic and acoustic cavitation alone, the effectiveness of oxidation was diversified. Under these conditions, nitro derivatives of benzene and phenol and its derivatives were found to be resistant to oxidation. In addition, hydrodynamic cavitation was found to be more effective in degradation of model compounds than acoustic cavitation. The results of investigations presented in this paper compare favorably with the investigations on degradation of organic contaminants using AOPs under conditions of basic pH published thus far
Power Transfer System
Get PDFA power transfer system and method are provided for transferring power from an AC supply outputting a first AC voltage. The system includes a controller and a matrix converter coupled to the AC supply for converting the first AC voltage to a second AC voltage. A primary coil is connected to the matrix converter and a secondary coil is in communication with the primary coil for producing an induced AC voltage. A secondary rectifier is connected to the secondary coil for rectifying the induced AC voltage to produce a secondary DC voltage. A sensor is coupled to the secondary rectifier and to the controller for monitoring the secondary DC voltage and outputting a proportional signal. The controller is configured to control the matrix converter producing a desired second AC voltage at a desired operating frequency and maintain a predetermined secondary DC voltage in response to the signal from the sensor
Digital Image Correlation Techniques for NDE and SHM
No full textMonitoring and analyzing the integrity of structures, infrastructure, and machines is essential for economic, operational, and safety reasons. The assessment of structural integrity and dynamic conditions of those systems is important to ensure safe operation and achieve or even extend the design service life. Recent advancements in camera technology, optical sensors, and image processing algorithms have made optically based and noncontact measurement techniques such as photogrammetry and digital image correlation (DIC) appealing methods for nondestructive evaluation (NDE) and structural health monitoring (SHM). Conventional sensors (e.g., accelerometers, strain gages, string potentiometers, LVDTs) provide results only at a discrete number of points. Moreover, these sensors need wiring, can be time-consuming to install, may require additional instrumentations (e.g., power amplifiers, data acquisition), and are difficult to implement on large-sized structures without interfering with their functionality or may require instrumentation having a large number of data channels. On the contrary, optical techniques can provide accurate quantitative information about full-field displacement, strain, geometry, and the dynamics of a structure without contact or interfering with the structure’s functionality. This chapter presents a summary review of the efforts made in both academia and industry to leverage the use of DIC systems for NDE and SHM applications in the fields of civil, aerospace, and energy engineering systems. The chapter also summarizes the feasibility of the approaches and presents possible future directions of the measurement approach
Development of a Semi-autonomous Drone for Structural Health Monitoring of Structures Using Digital Image Correlation (DIC)
No full textDigital Image Correlation (DIC) has proven itself to be a highly versatile and accurate method to measure 2D and 3D displacement, deformation, and strain in a wide range of structures and objects. A major advantage is that it is a non-contact, full-field measurement technique; it measures phenomena across the entire target object without having to attach sensors directly to the object. Despite the ability to measure many static and dynamic phenomena, the cameras and data acquisition equipment are almost exclusively set up in a static configuration. The cameras are often mounted on tripods and remain positioned in the same location while taking measurements. Such an immobile measurement platform prevents DIC from being employed to measure objects in inaccessible locations, such as bridges and tall buildings. An unmanned aerial vehicle carrying digital image correlation cameras has high mobility and can easily access regions on structures that would otherwise be too expensive or dangerous to measure with conventional static camera setups. This paper presents the development and testing of a prototype mobile digital image correlation platform. The resulting platform carries all of the necessary equipment on-board the drone and can be controlled by a single user with a remote control. It is shown that the prototype drone platform is capable of taking accurate and repeatable measurements while airborne. This drone aims to be used for vibration measurement and structural health monitoring of structures such as wind turbines and bridges
The Effect of Booster Seat Use on Pediatric Injuries in Motor Vehicle Frontal Crashes
No full textBackground: Motor vehicle crashes are a significant source of pediatric mortality and morbidity. Studies indicate that booster seats significantly improve seat belt fit for children who have not attained a height of 145 cm (4’ 9”). This study examined injuries occurring in booster age children up to age 12, as the majority of children do not attain 145 cm until this age. The purpose of the study was to identify differences in injuries due to the type of restraint used, with attention to musculoskeletal injuries. Methods: Vehicle and occupant data were obtained from a publically available statistical sample of tow-away crashes. Frontal crashes over an 8-year period were examined. A data set of cases was created involving children ages 5 to 12 years who were unrestrained, restrained using the vehicle’s lap and shoulder belt, and restrained using a booster seat with the vehicle’s lap and shoulder seat belt. Injury severity, frequency, and patterns of distribution were compared. Results: Unrestrained children experienced moderate to severe injuries 3.8 to 19 times more frequently than children using restraints. There were more injuries to the head and face in unrestrained versus restrained children, but the head and face was the most frequently injured region for all groups. There were no serious cervical spine injuries reported for any group. Lower extremity fractures were not observed in booster seat users but occurred at similar rates in both unrestrained and seat belt restrained children. These fractures occurred in older children who were involved in more severe crashes. Conclusions: Unrestrained children were more likely to experience moderate and severe injuries than restrained children. The data sample suggests that booster use may reduce the risk of extremity fracture, as there were no extremity fractures in children restrained with booster seats. Clinical Relevance: This work provides evidence for the efficacy of booster use for preventing orthopaedic injury in children. This evidence can be used to inform parents and establish recommendations for best practices in transporting children