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A bandwidth-enhanced $8\times 8$ cavity-backed slot array antenna for fixed beam applications is presented. The antenna consists of four $2\times 2$ subarrays fed by ridge gap waveguide and a modified bow-tie coupling slot in the cavity layer. The proposed bow-tie coupling slot provides additional $\text{10}\%$ impedance bandwidth as compared to the traditional rectangular coupling slot. The fabricated prototype demonstrates an $|S_{11}|\leq -10\,$ dB fractional impedance bandwidth and a $3\,$ dB gain-drop bandwidth of approximately $\text{28}\%$ and $\text{25}\%$ , respectively, with peak gain of $26.4\,$ dBi, aperture efficiency $>\text{60}\%$ and cross-polar discrimination $>40\,$ dB. Measurements show good agreement with simulations. Moreover, we show the impact of the dimensions and shape of the cavity coupling slot on the bandwidth enhancement. The bandwidth enhancement is explained by the double-ridge slot behavior of the bow-tie coupling slot, which shows a more wideband behavior than the traditional rectangular coupling slot behaving like a cross section of a waveguide.

Increasing the bending capacity of reinforced concrete (RC) elements is one of important topics in structure engineering. The goal of this study is to develop a transferred stress system (TSS) on longitudinal reinforcement bars for increasing the bending capacity of RC frames. The study is divided into two parts, i.e., experimental tests and nonlinear FE analysis. The experiments were carried out to determine the load-deflection curves and crack patterns of the ordinary and TSS fixed frame. The FE models were developed for simulating the fixed frames. The obtained load-deflection results and the observed cracks from the FE analysis and experimental tests are compared to evaluate the validation of the FE nonlinear models. Based on the validated FE models, the stress distribution on the ordinary and TSS bars were evaluated. We found the load carrying capacity and ductility of TSS fixed beam are 29.39% and 23.69% higher compared to those of the ordinary fixed beams. The crack expansion occurs on the ordinary fixed beam, although there are several crack openings at mid-span of the TSS fixed beam. The crack distribution was changed in the TSS fixed frame. The TSS fixed beam is proposed to employ in RC frame instead of ordinary RC beam for improving the performance of RC frame.

In this communication, a novel wideband fixed-beam leaky-wave antenna (LWA) is proposed. The antenna is designed based on air-filled substrate integrated waveguide (SIW), which is composed of one layer of printed circuit board (PCB) in the middle and two layers of thin copper plates on the top and bottom. The different layers are aligned and fixed by screws. A long slot is etched on the top surface of air-filled SIW as a radiator. Due to the dispersive characteristic of the air-filled SIW, the antenna can radiate at a fixed direction over a wideband. To the best of our knowledge, this is the first time that the air-filled SIW is adopted for LWA design. The proposed antenna is designed, fabricated, and tested. The measured results show that its wide operating bandwidth reaches up to 37.0%, ranging from 11 to 16 GHz. The excellent fixed-beam radiation performance is obtained over the operating bandwidth. The radiation direction is fixed at 59° with only ±3° variation, and the peak gain is within 14.0–15.3 dBi. Although the beam angle can only be fixed nearly the endfire, this method offers a simple way to realize wideband fixed-beam feature.

Some elementary particles used for experiments of fundamental physics have properties useful to the treatments of patients affected by oncological pathologies. They are protons and carbon ions, collectively named hadrons, hence the term hadron therapy. Hadrons, in particular carbon ions, are more precise on the target than conventional X-rays and possess radiobiological characteristics suited to treat radioresistant or inoperable tumors. Italy is at the forefront of these techniques, and in Pavia a clinical facility called CNAO (Italian acronym that stands for National Centre for Oncological Hadron therapy) has treated so far more than 2800 patients with very good results. The CNAO was created by the Health Ministry and was realized by the CNAO Foundation in collaboration with the Italian Institute of Nuclear Physics (INFN), CERN, GSI and other institutions in Italy and abroad. The facility in Pavia delivers beams of hadrons in three treatment rooms with four fixed beam ports: three horizontal and one vertical. A new room, with an horizontal beamline and multiple isocenters, was completed and will be fully devoted to research applications. The CNAO has also launched a development programe to add a new single room for proton therapy with a gantry and a dedicated accelerator. Attention is also devoted to the most interesting aspects of research and development in the hadron therapy domain, like the creation of a new BNCT (Boron Neutron Capture Therapy) facility and the design of a novel gantry for carbon ions.

Proton heavy ion radiotherapy is widely used and currently represents the most advanced radiotherapy technology. However, at present, proton heavy ion radiotherapy chairs in fixed beam radiotherapy rooms do not have a head and neck positioning function. This paper presents a novel design for a proton heavy ion radiotherapy chair with a head and neck positioning device. The design of the posture adjustment mechanism and the head and neck positioning device of the treatment chair is based on U-TRIZ theory and ergonomics, respectively. A positive kinematic analysis of the posture adjusting mechanism was carried out, as well as a workspace analysis of the head and neck positioning device. Finally, positioning error experiment and ergonomic evaluation were performed on a prototype of the head and neck positioning device. The proposed design of the treatment chair satisfies the requirements for posture adjustment and achieves the head and neck positioning function. The experimental results also provide a basis for further optimization of the design.

In this article, the vibration attenuation of a fixed-fixed beam with a piezo-shape memory alloy ferrule is theoretically investigated. First, a dynamic model of the beam with a piezo-shape memory alloy ferrule is established, and the nonlinear dynamic response of the model is numerically analysed. The results show that the stability of the beam structure can be improved adaptively through self-regulation of the stiffness of the piezo-shape memory alloy ferrule undergoing external excitations. The effects of some internal system characteristics, such as the ferrule dimensions as well as the initial ferrule temperatures and boundary conditions, on the vibration attenuation of the beam are discussed. The stability of the proposed model under different external factors, including damping and external excitations, is also investigated. Compared with an aluminium ferrule, the present ferrule is better at the suppressing vibrations of the beam, and its adaptive property avoids the structural resonances for bigger ferrule sizes, making it more intelligent, efficient and convenient.

Purpose To compare the fixed-beam intensity-modulated radiotherapy (IMRT) with the volumetric-modulated arc therapy (VMAT) plans for different cancers using the biologically effective dose (BED). Methods Recruited patients were divided into three groups in terms of tumor anatomic site, including head and neck, thoracic, and abdominal cancers. All of plans were generated using the fixed-beam IMRT and the VMAT techniques. The qualities of the plans were assessed using the conformity index (CI) and the homogeneous index (HI) with respect to the dose delivered to the tumors. Some selected organs-at-risk (OARs) were analyzed. For the efficiency of the plan, monitor units (MUs) were compared between the paired plans. All parameters were collected and evaluated based on the conventional dose-volume histogram (DVH) of the paired plans. All BED were calculated from the physical dose. Results For CI and HI, the fixed-beam IMRT and the VMAT gained significant differences (p Conclusion There is no difference in the data comparison of the paired plans using the BED values compared with the physical doses.

In this paper, test verification for a method of damage identification using artificial neural network (ANN) based on statistical properties of structural dynamic displacements was carried out. Six fixed beam models are fabricated, and damages on them are simulated by cutting a crack at their bottoms. Some damage samples were used to train the neural network and other samples were used to check the well-trained neural network. During the damage identification using back-propagation neural network (BPNN), the changes of variances (covariance) of structural displacements were adopted as input and location and extent of damage were as the output of BPNN. From the results of test verification in both single-damage case and multi-damage case, it is found that the ANN with the statistical property as damage index can accurately detect the damage location and can identify the damage extent with high precision, which denotes that the proposed method is effective and reliable for damage identification in civil engineering.

In this paper, we analyze the earth fixed beam of low earth orbit (LEO) satellite, which is currently undergoing standardization. Earth fixed beam LEO communicates with one coverage area for a certain period of time and moves beam after a certain period of time to communicate with the other. We check the tendency of cell throughput and analyze reference signal received power (RSRP), which is an indicator of handover and cell reselection, according to this time period.

Leaky-wave antennas radiating at zero and −1 spatial harmonics are considered. The analytical theory of synthesis for an antenna having a semi-transparent wall made of metal cylinders with a given distribution of radiated power along the antenna is developed. Waveguide-slot antennas with four longitudinal and three transverse slots per period are proposed and investigated. The possibilities of frequency scanning in the angular sector of 180 degrees are shown. A leaky-wave antenna with a waveguide prism and a fixed beam in a wide frequency band is studied.

Verification of beam-column resistance can be accomplished according to design approaches given in EN 1993-1-1 [1]. These approaches are derived from verification of single span beam with pinned end conditions subjected to compression and bending moments. In the case of different end conditions, the application of those approaches is not so accurate and more difficult. Therefore, the comparison of verification according to above standard EN 1993-1-1 [1] as well as EN 1999-1-1 [2] to results of experimental analyses of beam-columns having pinned-fixed end conditions subjected to an eccentric compressive force simulating the behaviour of columns integrated into frames is presented in this paper.

A 5-21 GHz fixed beam array system based on a novel radial LTCC feed and a PUMA array is presented. Through simulations it was found that total efficiency (antenna and feed) is >70%, with VSWR mostly less than 3 even for very small (18 element) arrays. The overall profile of the 4:1 bandwidth feed is less than 0.3 wavelengths at the highest frequency.

A low cost, low profile, high gain printed Yagi-Uda antenna with three pairs of off-center directors is presented for body area networks. The impedance bandwidth of the antenna is from 55 GHz to 59 GHz and the gain of the antenna is more than 10 dB. The end fire pattern of radiation and a high gain makes the designed structure suitable for On-Body links.

Purpose To evaluate the impacts of different leaf-width of multileaf collimator (MLC) on the fixed-beam intensity-modulated radiotherapy (IMRT) planning for prostate cancer patients with intermediate risk factors. Materials and methods Sixteen prostate cancer patients with intermediate risk factors were retrospectively recruited. For each patient, the two IMRT plans using MLC leaf width of 10 mm and 4 mm (sIMRT and mIMRT) were compared. All of plans were generated with the same setup and optimized parameters and methods. Homogeneity index (HI), conformity index (CI), dose distribution for planning tumor volume (PTV) and organs at risk (OARs) were analyzed to evaluate the quality of the plans. Delivery time (DT), monitor units (MUs) and control points (CPs) were used to assess the efficiency of treatment. Results For the target dose distribution, the mean HI values of the two plans for 16 patients are similar (sIMRT vs. mIMRT: 1.120±0.13 vs. 1.103±0.099, p>0.05). The mean CI of the mIMRT plans was significantly better than that of the sIMRT plans (sIMRT vs. mIMRT: 0.648±0.11 vs. 0.688±0.10, p Conclusions For the IMRT of the prostate cancer patients with intermediate risk factors, the plans with the narrower leaf-width MLC failed to promote the quality of plans, OARs dose sparing and the efficiency of treatment, and could only improve the conformity of the plans.

This paper describes a robotic patient positioning system (PPS) for a fixed-beam heavy-ion therapy system. In order to extend the limited irradiation angle range of the fixed beam, we developed a 6-degree-of-freedom (6-DOF) serial-link robotic arm and used it as the robotic PPS for the fixed-beam heavy-ion therapy system. This research aims to develop a robotic PPS for use in the Korea Heavy Ion Medical Accelerator (KHIMA) system, which is under development at the Korea Institute of Radiological & Medical Sciences (KIRAMS). In particular, we select constraints and criteria that will be used for designing and evaluating the robotic PPS through full consultation with KIRAMS. In accordance with the constraints and criteria, we develop a 6-DOF serial-link robotic arm that consists of six revolute joints for the robotic PPS, where the robotic arm covers the upper body of a patient as a treatment area and achieves a 15 ° roll and pitch angle in the treatment area without any collision. Various preliminary experiments confirm that the robotic PPS can meet all criteria for extension of the limited irradiation angle range in the treatment area and has a positioning repeatability of 0.275 mm.

Volumetric‐modulated arc therapy (VMAT) is emerging as a leading technology in treating early‐stage, non‐small cell lung cancer (NSCLC) with stereotactic ablative radiotherapy (SABR). However, two other modalities capable of delivering intensity‐modulated radiation therapy (IMRT) include fixed‐beam and helical TomoTherapy (HT). This study aims to provide an extensive dosimetric comparison among these various IMRT techniques for treating early‐stage NSCLC with SABR. Ten early‐stage NSCLC patients were retrospectively optimized using three fixed‐beam techniques via nine to eleven beams (high and low modulation step‐and‐shoot (SS), and sliding window (SW)), two VMAT techniques via two partial arcs (SmartArc (SA) and RapidArc (RA)), and three HT techniques via three different fan beam widths (1 cm, 2.5 cm, and 5 cm) for 80 plans total. Fixed‐beam and VMAT plans were generated using flattening filter‐free beams. SS and SA, HT treatment plans, and SW and RA were optimized using Pinnacle v9.1, Tomoplan v.3.1.1, and Eclipse (Acuros XB v11.3 algorithm), respectively. Dose‐volume histogram statistics, dose conformality, and treatment delivery efficiency were analyzed. VMAT treatment plans achieved significantly lower values for contralateral lung V5Gy(p≤0.05) compared to the HT plans, and significantly lower mean lung dose (p

A center-fed slot array antenna based on ridge gap waveguide (RGW) technology is presented. In the proposed structure, no aperture blockage is introduced which provides easy control on side lobe level (SLL) especially for low values of below −20 dB. Furthermore, thanks to the compact nature of TEM-based RGW line in E-plane, the proposed structure, unlike its TE-based groove gap waveguide (GGW) counterpart does not suffer from the grating lobe problem when applied in a two-dimensional array. For proof of concept a 4x10 slot array based on the proposed RGW-based topology is designed and fabricated for operation at 15 GHz. Both simulation and measurement results show proper radiation performance including the gain of 20 dB and the SLL of −23 dB as well as the fixed beam over the antenna operating bandwidth.

Description of dynamic behaviour of the structures is based on the mass, damping and stiffness matrices. Unfortunately, this description is inapplicable in case of the fluid-structure interaction (FSI), because the matrices of system, which consists of the structure and ambient fluid, are generally not known. The matrices of system, describing the FSI, can be determined by solution of inverse vibration problem, which is an approach employing the spectral matrix and modal matrices of analysed system. The eigenvalues for creation of the spectral matrix are determined based on experimental measurement. The results of experiment can be verified by numerical simulation. The modal matrices of structure submerged in fluid can be given by experiment, which is not simple in FSI problem, or by acoustic modal analysis. Third approach for determination of the modal matrices works with the assumption, that the eigenvectors of structure are not influenced by the fluid and are identical to the eigenvectors of structure without the ambient fluid. This assumption is generally correct for majority of FSI problems. Described method is demonstrated on determination of the matrices of dynamic systems of the fixed beam submerged in water.

We report on the first tunable plasma-core fiber based DUV-UV radiation source. The emission spans over 236-450 nm range. The source is a made with microwave-driven plasma-core photonic-crystal-fiber and with a fixed beam output-coupling configuration.

In this work we present the first phase results in the design of a fixed beam dual-polarized antenna at X-band for a polarimetric weather radar to be mounted on aircraft. Such a radar is not yet existent. Requirements pertinent to the application are presented and the different antenna system components described together with their simulated performances. Further steps in the development are anticipated. © 2017 European Microwave Association. AESS; APS; EurAPP

Loads applied on the floor are transferred through beams to columns. The beams can be designed as both end fixed or simple beams. The load bearing capacity of a beam depends on each boundary condition. However, when the load bearing capacity of a beam is evaluated in fire tests, all kinds of beams are tested using simple beam conditions. In this study, an analytical method performed using heat transfer theory and heat stress analysis based on the mechanical and thermal properties of SS-400 steel at high temperature. This method was used to clarify the differences between the two types of boundary conditions at normal and high temperature. The results show that the load bearing capacity of a both-end fixed beam at high temperature is superior to that of a simple beam. Therefore, the application of simple beam conditions in fire tests for evaluation of load bearing capacity is conservatively safe compared to fixed boundary conditions.

The induction of pulmonary capillary hemorrhage (PCH) by pulsed ultrasound was discovered 25 y ago, but early research used fixed-beam systems rather than actual diagnostic ultrasound machines. In this study, results of exposure of rats to fixed-beam focused ultrasound for 5 min at 1.5 and 7.5 MHz were compared with recent research on diagnostic ultrasound. One exposure condition at each frequency used 10-μs pulses delivered at 25-ms intervals. Three conditions involved Gaussian modulation of the pulse amplitudes at 25-ms intervals to simulate diagnostic scanning: 7.5 MHz with 0.3- and 1.5-μs pulses at 100- and 500-μs pulse repetition periods, respectively, and 1.5 MHz with 1.7-μs pulses at 500-μs repetition periods. Four groups were tested for each condition to assess PCH areas at different exposure levels and to determine occurrence thresholds. The conditions with identical pulse timing resulted in smaller PCH areas for the smaller 7.5-MHz beam, but both had thresholds of 0.69–0.75 MPa in situ peak rarefactional pressure amplitude. The Gaussian modulation conditions for both 7.5 MHz with 0.3-μs pulses and 1.5 MHz with 1.7-μs pulses had thresholds of 1.12–1.20 MPa peak rarefactional pressure amplitude, although the relatively long 1.5-μs pulses at 7.5 MHz yielded a threshold of 0.75 MPa. The fixed-beam pulsed ultrasound exposures produced lower thresholds than diagnostic ultrasound. There was no clear tendency for thresholds to increase with increasing ultrasonic frequency when pulse timing conditions were similar.

With the development of MEMS, more attention has been paid to the uniformity between the performance of the products in practical processing and the expected performance. A case study is conducted here with fixed-fixed beam and comb-drive resonator as the pattern to explore how geometry size deviation and geometry shape error influence the devices. It is discovered that the length, inclining profile and undercutting of the anchor is the key factor which influences the vibration mode of the fixed beam, and the geometry size and corrugating profile mainly affect the comb-drive resonator.

In order to calculate the crossbeam’s stress and deformation under the weight of gantry machine tool, and analyze whether the deformation meets the precision of design requirements. In this paper, we will use the finite element method to get the stress and deformation in different directions with finite element analysis software-ANSYS. The result shows that the maximum deformation is 14.3 microns which appeared in the middle part of the beam towards the gravity direction and the maximum stress is 4730000 Pa which appeared in the joint of pillar and beam.

Purpose: Charged particle facility design and operation presents numerous challenges, both technical and operational. The Mayo Clinic Proton Beam Therapy Program (PBTP) will consist of 2 proton radiation therapy facilities, each with 4 treatment gantries and 1 fixed beam room, located in Rochester, MN and Phoenix, AZ, respectively, operating under a single organizational structure. The proton facilities will open in 2015 and treat approximately 2,400 patients per year when fully operational. Materials and Methods: To facilitate development of a unified organizational culture for the Mayo Clinic PBTP, a survey consisting of open ended queries regarding facility design and organizational culture was sent to 36 charged particle treatment facilities worldwide and analyzed using McKinsey's 7-S model of organizational values. The survey was also given to the Mayo PBTP planning group. Results: The survey revealed the external respondents felt that aspects of organizational culture involving management s...

In this paper, an experimental procedure is proposed for determining the resonance frequencies and mode shapes of vibration of a fixed-fixed beam. Since it is fixed at both ends, the beam may sustain an axial force due to several factors including the fasteners and/or change of temperature. The analytical governing equations of motion, frequency equation, and mode shapes of vibration are presented. The analytical model is used to justify the experimental approach as well as interpretation of the experiment data. In this study, a hammer is used to excite the beam, and then the vibration of the beam is observed and recorded at two different points on the beam using two laser Doppler vibrometers. The data from the vibrometers are used to extract the resonance frequencies and mode shapes of vibrations. Using the analytical model, the axial force in the beam is estimated.

In this work we present the first phase results in the design of a fixed beam dual-polarized antenna at X-band for a polarimetric weather radar to be mounted on aircraft. Such a radar is not yet existent. Requirements pertinent to the application are presented and the different antenna system components described together with their simulated performances. Further steps in the development are anticipated. © 2017 European Microwave Association. APS; EurAAP

This paper provides a comparison between differential broadband series-fed and corporate-fed 4-element arrays at 60 GHz band to equip multi-channel radar. Radiator lengths are perturbed in the series-fed array to widen the bandwidth, while parasitic structures are inserted in the corporate-fed array. Measurement showed beam squinting from 3° to 15° over 61–66 GHz and narrow beam width for the compact series-fed array, while the large corporate-fed array has fixed beam direction but wider beam width. This opens the possibility of inherent beam steering by series-fed arrays for radar applications.