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A low average power pulsed Nd : YAG laser is used for bead-on-plate welding of low carbon steel plate. The criterion for welding in the conduction and keyhole regime together with the effect of laser process parameters on weld quality is studied. It is established that for a weld with full penetration and velocities viable for industrial applications, welding in the conduction mode would not be suitable. The formation of a keyhole is found to be highly dependent on laser pulse parameters. With an average power in the range 220–240 W and a peak power of 1.8 kW, full penetration through keyhole generation of a 0.7 mm thick st14 sheet metal is achieved.

Ingestible wireless capsule endoscopy (WCE) is the one and only painless, effective, novel, diagnostic technology for inspecting the entire gastrointestinal (GI) tract for various diseases, such as obscure gastrointestinal bleeding (OGIB), tumors, cancer, Crohn’s disease, and celiac disease. Since the development of this technology, several companies have made remarkable improvements in their clinical products, but there are still some limitations that relate to the use of conventional wired endoscopy. Some of the major limitations that currently impede its wider application include its inability to repeat the view of critical areas, working time constraints, and poor image resolution. Many research groups currently are working on ways to solve these limitations. Presently, developing the ability to control the movement of the capsule, increasing its image transmission speed, and obtaining high-quality images are the main issues in the research area. A complex capsule with some therapeutic tools for the treatment of diseases of the GI tract also is at the beginning of development for the next generation of an active medical robot. In this paper, we report the status of several activities related to WCE, including improvement of capsule technology, research progress, technical challenges, and key indicators concerning the next-generation, active, medical robot.

Abstract-This paper proposes a compact printed ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with a dimension of 38 × 91 mm 2 . The presented UWB-MIMO antenna comprises two identical patch elements with D separation distance on the same substrate. The basic single antenna structure has a novel design comprising seven circles surrounding a center circle with partial ground plane implementation. Furthermore, the experimental antenna has peak gain of 5.3 dBi between an operating frequency of 2.8 GHz and 8.0 GHz under a minimum reflection coefficient of less than −10 dB (S 11 < −10 dB). Moreover, the antenna successfully achieved mutual coupling minimization of < −17 dB, eventually resulting in enhancement of radiation efficiency. Besides, the UWB-MIMO's correlation coefficient was effectively reduced to less than −22 dB, which reflected an improvement in the antenna's diversity. In this paper, the proposed antenna is examined both numerically and experimentally.

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Abstract-In this paper, we propose a new approach to generate quadrupling-frequency optical millimeter-wave (mm-wave) signal with carrier suppression by using two parallel Mach-Zehnder modulators (MZMs) in Radio-over-fiber (RoF) system. Among the numerous properties of this approach, the most important is that a filterless optical mm-wave at 60 GHz with an optical sideband suppression ratio (OSSR) as high as 40 dB can be obtained when the extinction ratio of the MZM is 25 dB. Simplicity and cost-effectiveness have made this approach a compelling candidate for future wave-division-multiplexing RoF systems.Theoretical analysis is conducted to suppress the undesired optical sidebands for the high-quality generation of frequency quadrupling mm-wave signal. The simulation results show that a 60 GHz mm-wave is generated from a 15 GHz radio frequency (RF) oscillator with an OSSR as high as 40 dB and an radio frequency spurious suppression ratio (RFSSR) exceeding 35 dB without any optical or electrical filter when the extinction ratio of the MZM is 25 dB. Furthermore, the effect of the non-ideal RF-driven voltage as well as the phase difference of RF-driven signals applied to the two MZMs on OSSR and RFSSR is discussed and analyzed. Finally, we establish a RoF system through simulation to verify the transmission performance of the proposed scheme. The Q-factor performance and eye patterns are given.

Abstract-A change in the relative proportions of a mixture of rubber tire dust and rice husks will cause a change in the mixture's electrical permittivity and its ability to absorb electromagnetic energy. An openended coaxial probe was used in conjunction with three dielectric mixture equations (the Kraszewski equation, the Landau equation and the Lichtenecker equation) to obtain the dielectric properties of a mixture of rubber tire dust and rice husks (RTDRH) over the frequency range of 7 GHz to 13 GHz. Lichtenecker's equation for dielectrics proved to be a useful practical formulation for determining the effective permittivity of homogeneous dielectric mixtures. The effectiveness of these dielectric mixture equations in determining the effective permittivity of RTDRH was investigated in this study. A newly developed mixture equation was derived based on these dielectric

Individuals who report their sensitivity to electromagnetic fields often undergo cognitive impairments that they believe are due to the exposure of mobile phone technology. The aim of this study is to clarify whether short-term exposure at 1 V/m to the typical Global System for Mobile Communication and Universal Mobile Telecommunications System (UMTS) affects cognitive performance and physiological parameters (body temperature, blood pressure and heart rate). This study applies counterbalanced randomizing single blind tests to determine if sensitive individuals experience more negative health effects when they are exposed to base station signals compared with sham (control) individuals. The sample size is 200 subjects with 50.0% Idiopathic Environmental Intolerance attributed to electromagnetic fields (IEI-EMF) also known as sensitive and 50.0% (non-IEI-EMF). The computer-administered Cambridge Neuropsychological Test Automated Battery (CANTAB eclipseTM) is used to examine cognitive performance. Four tests are chosen to evaluate Cognitive performance in CANTAB: Reaction Time (RTI), Rapid Visual Processing (RVP), Paired Associates Learning (PAL) and Spatial Span (SSP). Paired sample t-test on the other hand, is used to examine the physiological parameters. Generally, in both groups, there is no statistical significant difference between the exposure and sham exposure towards cognitive performance and physiological effects (P’s > 0.05).