External Setup Research Articles

EXTERNAL AND INTERNAL WAVE SET-UP AT POROUS PBA REVETMENTS ON A SAND FOUNDATION

Wave set-up is generally considered for the stability analysis of beaches, but not or not explicitly for the design of revetments. Based on large-scale model results with regular and irregular waves, it is shown in this paper that this is not justified. For this purpose, the wave set-up on a porous bonded revetment and the related internal set-up in the sand foundation below the revetment are analysed for different breaker types. The results particularly show that (i) considerable set-up values are obtained for almost all breaker types, (ii) a good correlation exists with the deep water wave length for both external and internal set-up and (iii) the internal set-up is significantly affected by the wave set-up on the slope. Empirical formulae for the prediction of the external and internal set-up are also proposed for both regular and irregular waves.

Design and evaluation of an external high‐current target for production of 211At

This report presents the design and testing of an external target system for clinical‐scale production of 211At on the Scanditronix MC‐50 cyclotron at the University of Washington Medical Center. While other 211At production sites have typically employed an internal target, an external target setup was deemed necessary at our facility since the cyclotron's main application is for cancer patient treatment via fast neutron therapy. The challenge was that previous external 211At targets demonstrated reduced yields when compared to internal target systems. The target developed in this study has been used in more than 100 irradiations. From those irradiations 211At saturated yields of 181 ± 16 MBq/μA and 241 ± 17 MBq/μA at 28.0 and 29.0 MeV, respectively, were obtained. Importantly, consistent yields were observed over the 25–60 μA range of irradiation currents evaluated. With a recent production in excess of 4 GBq 211At for a 29.0 MeV, 58 μA, 4‐hour irradiation, this external target system has demonstrated its potential for producing clinically relevant quantities of 211At.

Carryover sequence-dependent group scheduling with the integration of internal and external setup times

This paper addresses a group scheduling problem in a two-machine flow shop with a bicriteria objective and carryover sequence-dependent setup times. This special type of group scheduling problem typically arises in the assembly of printed circuit boards (PCBs). The objective is to sequence all board types in a board group as well as board groups themselves in a way that the objective function is minimized. We introduce the carryover sequence-dependent setup on machines, and call it internal setup. As an opportunity for manufacturers to decrease the costs, the focus is to completely eliminate the role of the kitting staff. Thus, we introduce the external setup (kitting) time for the next board group and require it to be performed by the machine operator during the time he is idle. Consequently, the internal and external setup times are integrated in this research, and to the best of our knowledge it is for the first time a research on PCB group scheduling is performed by integrating both setups. In order to solve this problem, first a mathematical model is developed. Then a heuristic together with two other meta-heuristic algorithms (one based on tabu search and the other based on genetic algorithm) are proposed and their efficiency and effectiveness on several problems are tested. Also a statistical experimental design is performed in order to evaluate the impact of different factors on the performance of the algorithms.

Skin markings methods and guidelines: A reality in image guidance radiotherapy era

Preparation of site of radiation delivery is an important process in radiation treatment planning and plays a crucial role during a course of radiotherapy to achieve reproducibility of set-up and accuracy of treatment delivery. The preparation of treatment area is done by markings of field center, field edge or other reference point of planned field. Both non-invasive (marker pen, henna) and invasive methods (tattoo) are available for marking with limitations of each. Tattoo with a needle pricked at angle of 30° to 1-2 mm depth to create tattoo 2-3 mm diameter in size is an ideal procedure. Visibility, permanent nature, social-religious belief, and mobility of skin are one of the main concerns about tattoo. Tattoo removal can be done performed if desirable by patients by various modern ways, which will be esthetically available. Dermabrasion, cryotherapy, surgery, QSRL (Q-switched ruby laser) are common methods of tattoo removal. Esthetic dissatisfaction, allergy, dermatoses, keloids, infection, fanning/fading of tattoo are associated problems. In IMRT and IGRT treatment, delivery dependence on tattoo in reduced and use of surrogate markers including particularly for bony set-up and implanted markers (e.g. gold seeds) for tumor localization and treatment verification is increasing. However, these are complex procedures and require an expertise. Ease of set-up and less time required for tattooing are one of the main advantages of tattoo as compared to external or internal marker set-up. Tattoo still remains a crucial method of positioning, especially in developing countries and in palliative treatment settings.

A single machine carryover sequence-dependent group scheduling in PCB manufacturing

This paper considers the problem of minimizing the makespan on a single machine with carryover sequence-dependent setup times. A similar problem with multi-machine flow shop usually arises in the assembly of printed circuit boards (PCBs). This research investigates the possibility of processing all components of PCBs using just one machine. By doing so the operational costs of having multi-machines can be reduced, and as a result, finding an optimal solution might be more plausible. The objective is to minimize the maximum completion time of all board groups, commonly known as makespan. The operational constraints are such that all board types within a board group must be completely kitted, as it is traditionally performed by kitting staff, before that board group begins its assembly operation. We introduce the external setup (kitting) time and require that it be performed solely by the machine operator during the run time of the current board group, and thereby completely eliminating the need for kitting staff. The carryover sequence-dependent setup time, namely the internal (machine) setup time, is realized when a new board group is ready for assembly operation and is dependent on all of the previously scheduled board groups and their sequences. To the best of our knowledge, this is the first time the external and internal setup times are integrated in PCB group scheduling research. We develop a branch-and-bound algorithm and a lower-bounding structure. The lower bound consists of two approaches, which enable the algorithm to simultaneously reduce performing unnecessary exploration. In order to test the efficiency of the algorithm, several problem instances with different board groups have been used. The algorithm developed requires a significantly large computation time to optimally solve very large problems. Thus to speak for the efficiency in terms of solving comparable large industry-size problems, we evaluate the deviation of the algorithm from the lower bound which turns out to be very small, with an average of only 6%, in all of the problem instances considered.

Multimodal spectral control of a quantum-dot diode laser for THz difference frequency generation

Generation of stable dual and/or multiple longitudinal modes emitted from a single quantum dot (QD) laser diode (LD) over a broad wavelength range by using volume Bragg gratings (VBG’s) in an external cavity setup is reported. The LD operates in both the ground and excited states and the gratings give a dual-mode separation around each emission peak of 5 nm, which is suitable as a continuous wave (CW) optical pump signal for a terahertz (THz) photomixer device. The setup also generates dual modes around both 1180 m and 1260 nm simultaneously, giving four simultaneous narrow linewidth modes comprising two simultaneous difference frequency pump signals.

New external beam and particle detection set-up of Liège cyclotron – First applications of high energy beams to cultural heritage

Improvements on the Liége cyclotron have yielded an energy resolution comparable to that of classic electrostatic accelerators. The latest upgrades of the High-Energy High-Resolution beam line (HE-HR) are presented which consist of the addition of both a new extraction nozzle for non-invasive in-air measurements and a new particle-detection setup developed to take full advantage of the increased probed thickness with depth sensitive analytical methods. The suitability of the new setup and the advantages provided by the larger flexibility in choosing both the proper particle with an extended energy available will be illustrated by discussing latest results of studies recently led on Roman gilding techniques on cultural heritage artifacts by means of “High-Energy” alpha backscattering spectrometry combined with PIXE.

Pre-Hispanic ceramics analyzed using PIXE and radiographic techniques

Ceramics objects are the most common artifacts found during excavation of archaeological sites and often depicts cultural habits and manufacturing technologies of the culture. The determination of macroscopic and microscopic characteristics of the ceramic objects such as the ceramic porosity, addition of tempers in the clay, main chemical components and the trace elements present in the ceramic can reveal many aspects about the manufacturing processes used by the culture, its degree of development, the provenance of the raw materials and the exchange networks. Also the radiography can help to investigate the manufactured processes, the size of the tempers used and the conservation status of the artifacts. In this present work two non-destructive techniques, radiography and PIXE (Particle Induced X-ray Emission) were used to characterize one set of thirty-six pre-Hispanic ceramic pieces from the Chimu Culture conserved in the Museu de Arqueologia e Etnologia (MAE/USP). The PIXE analyses performed in the external beam setup at LAMFI (Laboratório de Análise de Materiais por Feixes Iônicos) allowed measure the principal chemical elements such as Al, Si, K, Ti, Fe and Ca, present in this group of pieces. X-ray imagings allowed identify the manufacture processes, the granularity of the tempers used, as well as the similarity and the differences between the pieces studied.

The new external ion beam analysis setup at the Demokritos Tandem accelerator and first applications in cultural heritage

At the 5.5 MV Tandem VdG accelerator of the Institute of Nuclear Physics of N.C.S.R. “Demokritos”, Athens, Greece, an external ion-beam set-up has been recently developed and installed. The aim of this development was to integrate the analytical capabilities of the PIXE, RBS and PIGE ion beam techniques in one experimental set-up, so that to attain a complete elemental and near surface structural characterization of samples in an almost non-destructive way and without any limitation concerning their size or conductive state. A careful 3D mechanical drawing optimized the set-up experimental parameters achieving probe dimensions at the millimeter range (1 mm 2) and fulfilling the special requirements imposed for optimum performance of the aforementioned techniques, including the possibility to use heavier, than protons, ion beams. For the digital pulse processing of the X-ray, γ-ray and charged particle detector signals, novel hardware and software tools were developed based on a custom FPGA configuration. The first applications were focused in the quality control of materials that have been intentionally contaminated with a particular tracer-element (“tagged” materials). The tagged materials which were developed and tested are technologically authentic replicas of ancient attic ceramics with black glazed decoration. Analytical diagnostic studies were carried out for a few representative paintings of contemporary Greek painters in order to identify and document materials/pigments and techniques and eventually to prevent trade of fakes. Finally, ancient glass beads were also examined with respect to the sodium concentration and its in-depth homogeneity.

2LB Anti-tumor activity of anti-RON antibodies and biomarker of response

Intensity-modulated proton therapy (IMPT) using pencil beam scanning (PBS) technology is advancing rapidly for delivering precise and more conformal doses to target volumes while sparing surrounding normal and critical tissues. To fully use the advantages of IMPT, immobilization and simulation is a critical step. The goal is to have small intra- and interfraction variations for the patient setup and have the setup uncertainty be well understood. A well-designed immobilizing system can also reduce the time for daily patient setup. Devices such as headrests, Vaclock, body bags, and so on, are constructed to reduce external setup uncertainty and patient movement, whereas rectal balloons are used to reduce internal motion during treatment of prostate patients, and spacers are used to create more separation between the target volume and critical normal structures.

Proton induced γ-ray emission yields for the analysis of light elements in aerosol samples in an external beam set-up

Abstract The PIXE technique is a reliable tool for the characterisation of thin aerosol samples, but it can underestimate the lightest measurable elements, like Na, Mg, Al, Si and P, owing to the absorption of their X-rays inside the sample. The PIGE technique is a valid help to determine corrections for such effect: in order to perform PIGE measurements relative to thin reference standards in an external beam set-up, we measured, at the external beam facility of the Tandetron accelerator of the LABEC laboratory in Florence, the γ-ray yields as a function of the proton beam energy for the reactions 19 F(p,p′γ) 19 F ( E γ = 110 and 197 keV), 23 Na(p,p′γ) 23 Na ( E γ = 440 keV) and 27 Al(p,p′γ) 27 Al ( E γ = 843 and 1013 keV), in the proton energy range from 3 to 5 MeV. The measured yields are shown, and the determined most suitable energies for performing PIGE quantification of Na and Al are reported, together with the corresponding minimum detection limits (MDLs). The results of some test on PIGE accuracy and an evaluation of self-absorption effects in PIXE measurements on thin aerosol samples are also presented.

External beamline setup for plated target investigation

Abstract The in-air beamline at the microanalytical center of the Jožef Stefan Institute in Slovenia has recently been upgraded with a wire-mesh current-integration normalization device and a RBS detector in helium flush. For positioning of the targets, the laser-triangulation with 40 μm repeatability was realized using 100 μm wide laser beam and a static camera. Metal plated historical objects were investigated for their gilded and tinned surfaces. Artificial samples were produced by dip-tinning and compared with archaeological samples. A surface roughness was found to be an important parameter for fitting the spectra by the SIMNRA software.

Microhand With Internal Visual System

A pneumatically operated four-fingered micromanipulator (a ldquomicrohandrdquo) with a fiber-based internal visual system is developed using microelectromechanical systems fabrication techniques. This ldquoseeingrdquo microhand transfers images generated by the optical system equipped at the palm of the microhand to an operator via an optical fiber bundle to provide the shape and distal information of objects of interest. The use of illuminating fibers along with the optical bundle enables the microhand's operation even in light-deficient environments. Such visual information informs the accurate relative location of the device and the status of manipulation to the operator in real time, who will take subsequent actions accordingly with an increased accuracy and efficiency. Embedding the fiber-based optical system inside the manipulator, instead of using an external camera setup for overall system monitoring, greatly reduces the size of the manipulator and helps increase maneuverability, particularly when operating in a space-limited work area. Tests have been conducted to verify the performance of the visually aided microhand to manipulate millimeter-sized objects in real time. Building on the ability of the UCLA microhand to gently handle irregular-shaped objects, this vision-enabled microhand is expected to provide more accurate manipulations and widen the window of applications.

Clinically Useful Observations of Prostate Motion using the Calypso Four-dimensional Localization System

Daily localization of the prostate has become a standard of care for external beam treatment (EBRT) of prostate cancer (PC). Also understood is the fact that the prostate gland has random motion in an individual during a EBRT session. No consensus exists as to the use of this information. Our objective was to observe inter- and intra-fraction motion of the prostate using the Calypso four-dimensional localization system (C) to guide CTV to PTV assumptions and adaptive treatment. This is an institutional review board-approved evaluation of 162 sessions of radiotherapy observed in 6 patients treated for PC using C. Each patient was setup to external markings daily and offsets detected by the C were recorded. Localization was confirmed by on-board imaging (OBI). Motion and time data was recorded 10 times each second throughout each treatment session. Nearly 2.5 million data points were used in this analysis. X = lateral motion, Y = anterior-posterior motion, and Z = superior-inferior motion. The paired t test method was used for statistical comparisons. The average daily offsets between external setup and C were 0.18 cm (range, 0.0-0.9), 0.16 cm (0.0-1.5), 0.26 cm (0.0-0.9) in the X, Y, and Z direction. Concordance was found between C and OBI localization (p = NS). Average motion for all sessions was 0.04 cm (range, 0.01-0.2) in X, 0.08 cm (0.01-0.28) in Y, and 0.09 cm (0.02-0.33) in Z directions, respectively. The average maximum motion for all sessions was 0.13 cm (range, 0.02-0.47) in X, 0.39 cm (0.07-5.05) in Y, and 0.42 cm (0.07-6.14) in Z directions, respectively. When considering margin, for all sessions, the time spent within 0.1 cm CTV to PTV expansion (X, Y, Z) is 96%, 70%, 69%; within 0.2cm is 100%, 91%, 91%; within 0.3 cm is 100%, 98%, 98%. For each patient, the average motion in the X, Y, and Z for the first 25% of sessions was not significantly different from the total remaining sessions in their treatment course for each patient. The Calypso four-dimensional localization system allowed the unique opportunity to observe significant, non-uniform intra-fraction motion of the prostate gland. X motion was less in magnitude than Y or Z. Based on 162 EBRT treatment sessions, a 0.1 cm CTV expansion in X dimension, and a 0.3 cm expansion in Y and Z dimensions would confine most random motion to within the prescribed dose envelope. In addition, the first sessions for each patient are predictive of motion for later sessions. This data has given us clinically useful information to help generalize prostate motion for treatment planning and future adaptive EBRT techniques. We have employed this data to design a clinical trial restricting motion and performing imaging when constraints are exceeded.

The use of biomonitors and PIXE analysis in the study of air pollution in Mexico City

AbstractAn environmental study of air contamination in the Valley of Mexico is under investigation based on the use of two biomonitors: the epiphytic lichen Flavopunctelia flaventior (L.) Nyl, and bromeliaceae Thillandsia recurvata (Ruiz and Pav), which are rather sensitive to air pollution and have a great capability to absorb and accumulate airborne mineral elements, including heavy metals. The thalli of lichen samples were collected in a controlled area, La Marquesa National Park, while bromeliaceae were collected in San Juan Teacalco, Estado de México. Samples were subsequently transplanted to 13 sites corresponding to 12 stations of the automatic network of atmospheric monitoring in the metropolitan area of the Valley of Mexico and a control site. This region includes urban and industrial places and one rural station. The study area is located at an altitude of 2240 m, with about 20 million inhabitants; it includes 3.5 million vehicles and 35 000 industries as well. The samples of transplanted lichen and bromeliaceae were exposed during 6 months in different seasonal periods during the year from 2002 to 2003. Pellets were prepared from ashes of the exposed lichens and bromeliaceae. The contents of Cr, Cu, Fe, Ni, Mn, Pb, Zn, and other trace elements were determined by particle‐induced x‐ray emission (PIXE), using an external proton beam setup. Copyright © 2008 John Wiley & Sons, Ltd.

3D Micro-PIXE at atmospheric pressure: A new tool for the investigation of art and archaeological objects

The paper describes a novel experiment characterized by the development of a confocal geometry in an external Micro-PIXE set-up. The position of X-ray optics in front of the X-ray detector and its proper alignment with respect to the proton micro-beam focus provided the possibility of carrying out 3D Micro-PIXE analysis. As a first application, depth intensity profiles of the major elements that compose the patina layer of a quaternary bronze alloy were measured. A simulation approach of the 3D Micro-PIXE data deduced elemental concentration profiles in rather good agreement with corresponding results obtained by electron probe micro-analysis from a cross-sectioned patina sample. With its non-destructive and depth-resolving properties, as well as its feasibility in atmospheric pressure, 3D Micro-PIXE seems especially suited for investigations in the field of cultural heritage.

Image‐guided helical tomotherapy for localized prostate cancer: technique and initial clinical observations

The purpose of the present study was to implement a technique for daily computed tomography (CT)–based image‐guided radiation therapy and to report observations on treatment planning, imaging, and delivery based on the first 2 years of clinical experience.Patients with previously untreated stage T1 – T3 biopsy‐proven adenocarcinoma of the prostate were considered eligible for treatment with daily CT‐guided helical tomotherapy. The prostate was targeted daily using megavoltage CT (MVCT) images that were fused with treatment‐planning CT images based on anatomic alignments. All patients were treated at 2 Gy per fraction to 76 – 78 Gy (mean: 76.7 Gy).As part of this study, 33 prostate patients were planned, imaged, and treated with a total of 1266 CT‐guided fractions. The prostate, rectum, bladder, femoral heads, and pubis symphysis were visible in one or more slices for all 1266 MVCT image sets. The typical range of measured prostate displacement relative to a 3‐point external laser setup in this study was 2 – 10 mm [3.4 mm standard deviation (SD)] in the anterior–posterior direction, 2 – 8 mm (3.7 mm SD) in the lateral direction, and 1 – 6 mm (2.4 mm SD) in the superior–inferior direction. The obese patients in this study had a substantially larger lateral variation (8.2 mm SD) attributable to mobility of skin marks. The prostate, seminal vesicles, rectum, and bladder anatomy were used to position the patient relative to the desired treatment position without the use of implanted markers. Acute toxicities were within the expected range given the number of patients treated and the dose level.PACS numbers: 87.50.Gi, 87.53.Mr, 87.53.Tf

Concise Matrix Analysis of Point-Based Prostate Targeting for Intensity Modulated Radiation Therapy

Intensity Modulated Radiation Therapy (IMRT) has recently emerged as an effective clinical treatment tool to treat various types of cancers by limiting the external beam dose to the surrounding normal tissue. However, the process of limiting external radiation dose to the tissue surrounding the tumor volume is not a trivial task. Several parameters including tumor volume and inhomogeneity, position and shape of the tumor volume, and the geometrical distribution of the radiation beams directly affect the determination of the external radiation dose. In addition, a major variable in effective delivery of the radiation dose is "set-up error" caused by the changes in patient position. Any changes in the position of the patient affect the geometrical location of the tumor volume and, therefore, need to be accommodated in the delivery of radiation beams during the treatment. This work presents a complete matrix representation required to calculate the three-dimensional rigid body homogeneous transformation matrices corresponding to external beam radiotherapy setup error and subsequent corrections in treatment beam parameters. A new concise orthogonal rotation solution is presented for use with clinical noisy data. Monte Carlo simulations prove the new matrix results are consistently better than the standard inverse solution. The required corrections in beam table, gantry, and collimator angles as function of the planned beam gantry angle are derived. For transformations that include a rotation on the sagittal plane, the required offsets to beam parameters are complex functions of the planned gantry angle but are clearly documented graphically for clinical use. A case study is presented with an error analysis that supports the use of the presented method in a clinical environment. Clinical implementation and evaluation of the presented method with patient data is also included in the paper.

The Grolier Codex: A Non Destructive Study of a Possible Maya Document using Imaging and Ion Beam Techniques

AbstractThe Grolier Codex has been a controversial document ever since its late discovery in 1965. Because of its rare iconographical content and its unknown origin, specialists are not keen to assure its authenticity that would set it amongst the other tree known Maya codes in the world (Dresden, Paris Codex and Madrid Codex).The document that has been kept in the Museo Nacional de Antropología in Mexico City, after its exposure in 1971 at the Grolier Club of New York, has been analyzed by a set of non-destructive techniques in order to characterize its materials including paper fibers, preparation layer and colors composition. The methodology included UV imaging, IR reflectography and optic microscopy examinations as well as Particle Induced X-ray Emission (PIXE) and Rutherford Backscattering Spectrometry (RBS) using an external beam setup for elemental analysis. All the measurements were carried out at 3MV Pelletron Accelerator of the Instituto de Física, UNAM. The aim of this work is to verify if the materials in the Grolier Codex match those found for other pre-Hispanic documents.From the elemental composition we concluded that the preparation layer shows the presence of gypsum (CaSO4), color red is due to red hematite (Fe2O3) and black is a carbon-based ink. These results agree with previous analyses carried out by Scanning Electron Microscopy (SEM-EDX) on few samples. However, the presence of Maya Blue in the blue pigment cannot be assured. The examination using UV and IR lights shows homogeneity in the inks and red color but dark areas that contain higher amounts of K in the preparation layer. This paper discusses the results obtained for the UV-IR examinations and the elemental analysis. A comparison with other studies on pre-Hispanic and early colonial codex is presented.

External-beam PIXE spectrometry for the study of Punic jewellery (SW Spain): The geographical provenance of the palladium-bearing gold

This paper presents the study of a set of Punic gold items (400 B.C.), from the Museum of Cádiz (Spain). An external beam set-up has been employed for the absolutely non-destructive analysis of the objects. PIXE spectrometry has been performed in order to characterize the metallic alloys and the manufacturing techniques. Compositional differences have been found and soldering procedures have been identified. By comparison with the rings and other coetaneous jewellery, the presence of palladium in the bulk alloy of the earrings can be pointed out. The geographical provenance of the palladium-bearing gold is discussed based on geological and archaeological considerations.