Effect of Eccentricity in Microwave Imaging of Multiple Composite Pipes

The use of non-metallic composites that are durable, low cost, and lightweight is growing fast in various industries. A commonly used form of these materials is in the shape of pipes that can be used, for instance, in oil and gas industry. Such pipes can be damaged due to material loss (defects and holes), erosions, and more which may cause major production failures or environmental mishaps. To prevent these issues, non-destructive testing (NDT) methods need to be employed for regular inspections of such components. Since traditional NDT methods are mainly used for metallic pipes, recently microwave imaging has been proposed as a promising approach for examination of non-metallic pipes. While microwave imaging can be employed for inspection of multiple layers of pipes, the effect of undesired eccentricity of the pipes can impose additional imaging errors. In this paper, for the first time, we study the effect of eccentricity of the pipes on the images reconstructed using near-field holographic microwave imaging when imaging double pipes

Three-Dimensional Near-Field Microwave Holography for Tissue Imaging

This paper reports the progress toward a fast and reliable microwave imaging setup for tissue imaging exploiting near-field holographic reconstruction. The setup consists of two wideband TEM horn antennas aligned along each other's boresight and performing a rectangular aperture raster scan. The tissue sensing is performed without coupling liquids. At each scanning position, wideband data is acquired. Then, novel holographic imaging algorithms are implemented to provide three-dimensional images of the inspected domain. In these new algorithms, the required incident field and Green's function are obtained from numerical simulations. They replace the plane (or spherical) wave assumption in the previous holographic methods and enable accurate near-field imaging results. Here, we prove that both the incident field and Green's function can be obtained from a single numerical simulation. This eliminates the need for optimization-based deblurring which was previously employed to remove the effect of realistic non-point-wise antennas

First report of tinea corporis caused by Trichophyton quinckeanum in Iran and its antifungal susceptibility profile

Background and Purpose: Trichophyton quinckeanum, a known zoophilicdermatophyte responsible for favus form in rodents and camels, is occasionally reported to cause human infections.Case Report: This study aimed to report a case of tinea corporis caused by T. quinckeanum that experienced annular erythematous pruritic plaque with abundantpurulent secretions. In June 2021, a 15-year-old girl with an erythematous cup shape lesion on the right wrist bigger than 3 cm in diameter was examined for tinea corporis. Since March, 2016 her family has kept several camels at home. Direct examination of skin scraping and purulent exudates revealed branching septal hyaline hyphae and arthrospore. Morphological evaluation of the recovered isolate from the culture and sequencing of ITS1-5.8S rDNA-ITS2 region resulted in the identification of T. quinckeanum. Antifungal susceptibility testing showed that this isolate had low minimum inhibitory concentration (MIC) values for luliconazole,terbinafine, and tolnaftate, but high MICs to itraconazole, fluconazole, posaconazole, miconazole, isavuconazole, ketoconazole, clotrimazole, andgriseofulvin. However, the patient was successfully treated with oral terbinafine andtopical ketoconazole.Conclusion: It can be said that T. quinckeanum is often missed or misidentified due to its morphological similarity to T. mentagrophytes/T. interdigitale or other similar species. This dermatophyte species is first reported as the cause of tinea corporis in Iran. As expected, a few months after our study, T. quinckeanum was detected in other areas of Iran, in a few case

Applications of Electromagnetic Waves: Present and Future

Electromagnetic (EM) waves carry energy through propagation in space [...

A Low-Cost and Compact Three-Dimensional Microwave Holographic Imaging System

With the significant growth in the use of non-metallic composite materials, the demands for new and robust non-destructive testing methodologies is high. Microwave imaging has attracted a lot of attention recently for such applications. This is in addition to the biomedical imaging applications of microwave that are also being pursued actively. Among these efforts, in this paper, we propose a compact and cost-effective three-dimensional microwave imaging system based on a fast and robust holographic technique. For this purpose, we employ narrow-band microwave data, instead of wideband data used in previous three-dimensional cylindrical holographic imaging systems. Three-dimensional imaging is accomplished by using an array of receiver antennas surrounding the object and scanning that along with a transmitter antenna over a cylindrical aperture. To achieve low cost and compact size, we employ off-the-shelf components to build a data acquisition system replacing the costly and bulky vector network analyzers. The simulation and experimental results demonstrate the satisfactory performance of the proposed imaging system. We also show the effect of number of frequencies and size of the objects on the quality of reconstructed images

Wearable Inductive Sensing of the Arm Joint: Comparison of Three Sensing Configurations

Currently, there is a rapidly growing interest and demand for wearable textile sensors that can monitor human motions in a naturalistic environment. Some potential applications for this technology include research on measuring the motor skill performance of patients with motor disabilities such as autism spectrum disorder, Parkinson’s disease, cerebral palsy, and stroke and evaluating the efficacy of applied treatments. Among wearable sensors, inductive sensors that are made from highly conductive threads are attractive due to their easy development process, high reliability, and low cost. In this study, we analyzed and compared the performance of three inductive wearable sensor configurations—(1) single planar rectangular coil, (2) two separated coils connected in series, and (3) two helical coils connected in series—in terms of the change in the resonant frequency of the tank circuit they comprised as a result of the change in elbow joint angle through simulations. Three parameters of length, width, and the number of turns were considered to calculate sensor sensitivity to the joint angle. The coil with the highest sensitivity was then fabricated and measured, and its performance was compared with the simulation results. The proposed methodology can be extended to sensing other joints in the body such as the shoulders, fingers, and knees

A Systematic Review of the Factors Affecting Access to Finance in Entrepreneurial Activities

Access to finance plays a key role in developing small and medium-sized enterprises (SMEs) and entrepreneurial activities. Despite the critical role in economic growth and entrepreneurial activities, access to finance is the main problem. Better access to financial resources for a company's formation or development leads to better allocation of production resources, leading to rapid economic growth. Given the various theories about the factors influencing access to finance, there is still a lack of a systematic view of the factors affecting finance access. It implies that research areas are not yet saturated in this research field. Policymakers, therefore, need to understand the impact of various factors on access to finance for policymakers. This study aims to identify the factors for entrepreneurial activities that affect access to finance. To this end, 139 articles (Persian and English) on the factors affecting access to finance for entrepreneurial activities are reviewed using the systematic review of experimental and theoretical literature. Resources are then grouped into two internal and external factors categories. The results showed that the external factors included bank concentration, financial performance, debt conditions (interest rates, leverage and repayment periods), macroeconomic volatility, corruption, and companies' geography and knowledge asymmetry. Additionally, internal factors include entrepreneurial characteristics (age, gender, education, entrepreneurship and network of experience), company characteristics (life span of the company, size of the company, type of company and property, plant and equipment) and financial management practices of the company (financial information, business plan, and capital budgeting and management of working capital). This study's results enable policymakers to have effective strategies to promote access to business finance and enable entrepreneurs to recognize their strengths and limitations in accessing finance

Fast, Robust, and Low-Cost Microwave Imaging of Multiple Non-Metallic Pipes

The use of non-metallic pipes and composite components that are low-cost, durable, light-weight, and resilient to corrosion is growing rapidly in various industrial sectors such as oil and gas industries in the form of non-metallic composite pipes. While these components are still prone to damages, traditional non-destructive testing (NDT) techniques such as eddy current technique and magnetic flux leakage technique cannot be utilized for inspection of these components. Microwave imaging can fill this gap as a favorable technique to perform inspection of non-metallic pipes. Holographic microwave imaging techniques are fast and robust and have been successfully employed in applications such as airport security screening and underground imaging. Here, we extend the use of holographic microwave imaging to inspection of multiple concentric pipes. To increase the speed of data acquisition, we utilize antenna arrays along the azimuthal direction in a cylindrical setup. A parametric study and demonstration of the performance of the proposed imaging system will be provided

Investigation physical properties and decay resistance of Medium Density Fiberboard sanding powder- polyethylene-nanoclay composite

In this study, the effect of nanoclay and coupling agent on decay resistance and physical properties (including water absorption and thickness swelling) of nanoclay- Polyethylene- MDF sanding- powder composite were investigated. For this aim, MDF sanding dust and polyethylene were used as lignocellulose and thermoplastic material respectively. Also, Maleic anhydride grafted polyethylene (MAPE) was used in different weight percentages; 3% and 6% as a compatibilizer and nanoclay .Cloisite®15A was used in different weight percentages 2%, 4% and 6%.At first, raw materials were producted to fabricate granules by using twin-screw extruder. Then 36 panels (12 treatments by 3 repetitions) were made by hot pressing with 1 g/cm3 nominal density at dimensions by 30 cm × 28 cm × 1 cm. Then, water absorption and thickness swelling and decay resistant (loss weight) were investigated. Specimens were exposed to Trametes versicolor for 3 months, according to ASTM-D1413 standard. The results shown, water absorption and thickness swelling reduce with increasing MAPE significantly. While, at the time when nanoclay was added 2% (phr), water absorption and thickness swelling reduced significantly and then increased. Also, decay resistance was improved with increasing coupling agent and nanoclay