Initial Performance Evaluation Research Articles

Initial evaluation of image performance of a 3-D x-ray system: phantom-based comparison of 3-D tomography with conventional computed tomography.

Phantom-based initial performance assessment of a prototype three-dimensional (3-D) x-ray system and comparison of 3-D tomography with computed tomography (CT) were proposed. A 3-D image quality phantom was scanned with a prototype version of 3-D cone-beam CT imaging implemented on a twin robotic x-ray system using three trajectories (163deg = table, 188deg = upright, and 200deg = side), six tube voltages (60, 70, 81, 90, 100, and 121kV), and four detector doses (0.348, 0.696, 1.740, and [Formula: see text]). CT was obtained with a clinical protocol. Spatial resolution (line pairs/cm) and soft-tissue-contrast resolution were assessed by two independent readers. Radiation dose was assessed. Descriptive and analysis of variance (ANOVA) ([Formula: see text]) were performed. With 3-D tomography, a maximum of 16 lp/cm was visible and best soft-tissue-contrast resolution was 2mm at 30 Hounsfield units (HU) for 160 projections. With CT, 10 lp/cm was visible and soft-tissue-contrast resolution was 4mm at 20 HU. The upright trajectory yielded significantly better spatial resolution and soft tissue contrast, and the side trajectory yielded significantly higher soft tissue contrast than the table trajectory ([Formula: see text]). Radiation dose was higher in 3-D tomography (45 to 704 mGycm) than CT (44 mGycm). Three-dimensional tomography renders overall equal or higher spatial resolution and comparable soft tissue contrast to CT for medium- and high-dose protocols in the side and upright trajectories, but with higher radiation doses.

Initial performance evaluation of a spotted array Mobile Analysis Platform (MAP) for the detection of influenza A/B, RSV, and MERS coronavirus

Clinical samples were evaluated with the Mobile Analysis Platform (MAP) to determine platform performance for detecting respiratory viruses in samples previously characterized using clinical reverse transcriptase polymerase chain reaction assays. The percent agreement between MAP and clinical results was 97% for influenza A (73/75), 100% (21/21) for influenza B, 100% (6/6) for respiratory syncytial virus (RSV), and 80% (4/5) for negative specimens. The approximate limit of detection of the MAP was 30 copies/assay for RSV and 1500 copies/assay for Middle East respiratory syndrome coronavirus.

Development of a position-sensitive scintillation neutron detector for a new protein single-crystal diffractometer at J-PARC MLF

A high-spatial-resolution, large-area position-sensitive scintillation-based neutron detector module has been developed for a new time-of-flight Laue single-crystal diffractometer to be constructed at J-PARC MLF. A first prototype detector implementing commercial 6Li:ZnS screens was produced based on a scintillator/wavelength-shifting fibre technology. The detector exhibited a spatial resolution of 2.5 mm with a neutron-sensitive area of 320 × 320 mm2. We report on an initial evaluation of the detector performance, including its spatial resolution, detection efficiency and long-term background measurement, and also provide a brief description of a new neutron instrument.

The effects of educational delivery methods on knowledge retention

ABSTRACTIn today's dynamic learning environment, educational delivery methods have become increasingly diverse. Using a unique opportunity to assess three types of course delivery—face-to-face, interactive television (iTV), and purely online delivery—the authors look at both initial knowledge acquisition and the retention of this knowledge. The results indicate that the online class outperformed the face-to-face and iTV sections on the initial performance evaluation; however, knowledge retention was greater in the face-to-face and iTV sections. The authors' findings suggest that diverse educational delivery methods provide unique benefits to students, but these benefits vary in relation to immediate learning outcomes and knowledge retention.

Evaluation of Electrochemical Properties of LSCF Electrode with GDC Barrier Layer under both Fuel Cell and H2O/CO2 Co-Electrolysis Modes

In this study, La0.6Sr0.4Co0.2Fe0.8O3- δ (LSCF) oxygen electrode as well as Gd0.1Ce0.9O2- δ (GDC) barrier layer was employed by the screen printing process for both fuel cell and H2O/CO2 co-electrolysis operations. After initial performance evaluation of the cell under SOFC mode, electrochemical measurements of the cell were carried out at 700-800 oC for co-electrolysis mode with 45% H2O, 45% CO2 and 10% H2 as fed gas. Further, the long-term durability of the cell was examined at a constant current of 0.4 A*cm-2 for over 200 h. It showed that cell voltage held at a steady value after experiencing initial significant fluctuations.

Structure and mechanical behavior of Big Area Additive Manufacturing (BAAM) materials

PurposeThis paper aims to investigate the deposited structure and mechanical performance of printed materials obtained during initial development of the Big Area Additive Manufacturing (BAAM) system at Oak Ridge National Laboratory. Issues unique to large-scale polymer deposition are identified and presented to reduce the learning curve for the development of similar systems.Design/methodology/approachAlthough the BAAM’s individual extruded bead is 10-20× larger (∼9 mm) than the typical small-scale systems, the overall characteristics of the deposited material are very similar. This study relates the structure of BAAM materials to the material composition, deposition parameters and resulting mechanical performance.FindingsMaterials investigated during initial trials are suitable for stiffness-limited applications. The strength of printed materials can be significantly reduced by voids and imperfect fusion between layers. Deposited material was found to have voids between adjacent beads and micro-porosity within a given bead. Failure generally occurs at interfaces between adjacent beads and successive layers, indicating imperfect contact area and polymer fusion.Practical implicationsThe incorporation of second-phase reinforcement in printed materials can significantly improve stiffness but can result in notable anisotropy that needs to be accounted for in the design of BAAM-printed structures.Originality/valueThis initial evaluation of BAAM-deposited structures and mechanical performance will guide the current research effort for improving interlaminar strength and process control.

21 Tesla Fourier Transform Ion Cyclotron Resonance Mass Spectrometer Greatly Expands Mass Spectrometry Toolbox.

We provide the initial performance evaluation of a 21 Tesla Fourier transform ion cyclotron resonance mass spectrometer operating at the Environmental Molecular Sciences Laboratory at the Pacific Northwest National Laboratory. The spectrometer constructed for the 21T system employs a commercial dual linear ion trap mass spectrometer coupled to a FTICR spectrometer designed and built in-house. Performance gains from moving to higher magnetic field strength are exemplified by the measurement of peptide isotopic fine structure, complex natural organic matter mixtures, and large proteins. Accurate determination of isotopic fine structure was demonstrated for doubly charged Substance P with minimal spectral averaging, and 8158 molecular formulas assigned to Suwannee River Fulvic Acid standard with root-mean-square (RMS) error of 10ppb. We also demonstrated superior performance for intact proteins; namely, broadband isotopic resolution of the entire charge state distribution of apo-transferrin (78kDa) and facile isotopic resolution of monoclonal antibody under a variety of acquisition parameters (e.g., 6s time-domains with absorption mode processing yielded resolution of approximately 1M at m/z = 2700). Graphical Abstract ᅟ.

The weather@home regional climate modelling project for Australia and New Zealand

Abstract. A new climate modelling project has been developed for regional climate simulation and the attribution of weather and climate extremes over Australia and New Zealand. The project, known as weather@home Australia–New Zealand, uses public volunteers' home computers to run a moderate-resolution global atmospheric model with a nested regional model over the Australasian region. By harnessing the aggregated computing power of home computers, weather@home is able to generate an unprecedented number of simulations of possible weather under various climate scenarios. This combination of large ensemble sizes with high spatial resolution allows extreme events to be examined with well-constrained estimates of sampling uncertainty. This paper provides an overview of the weather@home Australia–New Zealand project, including initial evaluation of the regional model performance. The model is seen to be capable of resolving many climate features that are important for the Australian and New Zealand regions, including the influence of El Niño–Southern Oscillation on driving natural climate variability. To date, 75 model simulations of the historical climate have been successfully integrated over the period 1985–2014 in a time-slice manner. In addition, multi-thousand member ensembles have also been generated for the years 2013, 2014 and 2015 under climate scenarios with and without the effect of human influences. All data generated by the project are freely available to the broader research community.

Design and Evaluation of a Mesoscale Segmented Flow Reactor (KRAIC)

The design and development of a mesoscale flow reactor is presented, together with initial performance evaluation. The custom-designed KRAIC (kinetically regulated automated input crystallizer) uses liquid-segmented flow to achieve plug flow and mixing throughout the reactor length while helping prevent encrustation issues experienced by other precipitation reactors and crystallizers. Evaluation of the reactor for production of solid-state particle products has been carried out using cooling crystallization of fast growing succinic acid to explore the potential of the KRAIC design to mediate blocking caused during the precipitation process. The segmented flow environment is successful in preventing encrustation during an unseeded 2 h cooling crystallization experiment.

P169 Comparison of the FTD™ Urethritis Plus (7-Plex) detection kit with routine sexual health clinic nucleic acid amplification testing for detection ofNeisseria gonorrhoeaeandChlamydia trachomatisin urine, vaginal, pharyngeal and rectal samples: Abstract P169 Table 1

Background/introduction The FTD™ Urethritis Plus (FTDU) nucleic acid amplification test (NAAT) detects seven pathogens associated with urethritis, including Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium, Trichomonas vaginalis, Mycoplasma hominis, Ureaplasma urealyticum and Ureaplasma parvum. Aim(s)/objectives To perform an initial diagnostic evaluation of FTDU performance for NG and CT, compared to routine clinic NAAT (BD Viper), in prospectively collected genital samples from symptomatic patients. Methods Alongside routine clinical samples, additional samples (n = 684) were taken from symptomatic patients: females (vulvovaginal swabs; VVS), men-who-have-sex-with-women (MSW) (urine) and men-who-have-sex-with-men (MSM) (rectal and pharyngeal swabs; urine). Results The prevalence of CT was 9.38% across sample sites tested (24 Female, 21 Male, 3 MSM Urine, 1 MSM Pharynx and 5 MSM Rectal positives). The prevalence of NG was 9.74% across sample sites tested (5 Female, 6 Male, 10 MSM Urine, 17 MSM Pharynx and 19 MSM Rectal positives). Discussion/conclusion FTDU was accurate for detecting CT from genital sites only and had poor sensitivity for NG at all sampling sites. This test could not be used for NG testing for urine or extra genital testing without supplementary testing according to the BASHH guidelines as the PPV is below 90%. Further work is required to establish its suitability for detecting the other organisms claimed.

Initial PET performance evaluation of a preclinical insert for PET/MRI with digital SiPM technology

Hyperion-IID is a positron emission tomography (PET) insert which allows simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner. To read out the scintillation light of the employed lutetium yttrium orthosilicate crystal arrays with a pitch of 1 mm and 12 mm in height, digital silicon photomultipliers (DPC 3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET performance in terms of energy resolution, coincidence resolution time (CRT) and sensitivity as a function of the operating parameters, such as the operating temperature, the applied overvoltage, activity and configuration parameters of the DPCs, has been evaluated at system level. The measured energy resolution did not show a large dependency on the selected parameters and is in the range of 12.4%–12.9% for low activity, degrading to ∼13.6% at an activity of ∼100 MBq. The CRT strongly depends on the selected trigger scheme (trig) of the DPCs, and we measured approximately 260 ps, 440 ps, 550 ps and 1300 ps for trig 1–4, respectively. The trues sensitivity for a NEMA NU 4 mouse-sized scatter phantom with a 70 mm long tube of activity was dependent on the operating parameters and was determined to be 0.4%–1.4% at low activity. The random fraction stayed below 5% at activity up to 100 MBq and the scatter fraction was evaluated as ∼6% for an energy window of 411 keV–561 keV and ∼16% for 250 keV–625 keV. Furthermore, we performed imaging experiments using a mouse-sized hot-rod phantom and a large rabbit-sized phantom. In 2D slices of the reconstructed mouse-sized hot-rod phantom (∅ = 28 mm), the rods were distinguishable from each other down to a rod size of 0.8 mm. There was no benefit from the better CRT of trig 1 over trig 3, where in the larger rabbit-sized phantom (∅ = 114 mm) we were able to show a clear improvement in image quality using the time-of-flight information. The findings will allow system architects—aiming at a similar detector design using DPCs—to make predictions about the design requirements and the performance that can be expected.

Towards earthquake early warning for the Rion-Antirion bridge, Greece

Patras is the third largest city in Greece and an ideal candidate for earthquake early warning (EEW) applications due to its high seismic hazard, its existing research infrastructure and the presence of critical structures such as the Rion-Antirion bridge. Patras is located a few hundred kilometres from the Hellenic Arc, where very strong and potentially damaging earthquakes occur. This distance is large enough to allow a few tens of seconds of warning time prior to significant shaking, provided earthquakes are timely detected by a dense seismic network. Within the framework of the EC-funded project REAKT, the Virtual Seismologist (VS) EEW software was installed at Patras Seismological Laboratory. Its initial performance evaluation is presented here. In general VS provides magnitudes similar to the official, manually revised ones. Given the current station density and network telemetry, the average time that VS needs to deliver the first magnitude estimate is rather large, of the order of tens of seconds and not yet satisfactory for routine operational use of EEW. Even so, the system is able to provide up to 10 s of warning time prior to S-wave arrivals for events occurring on the Hellenic Arc. Our results indicate that the seismic networks in Greece need enhancements for regional EEW, either by adding stations or by upgrading the hardware to reduce delays. The application of an EEW system in the area is promising and, once operational, capable of mitigating earthquake risk.

THE EFFECTIVENESS OF THE SOLAR ENERGY USE FOR POWER SUPPLY IN THE CLIMATIC CONDITIONS OF KYRGYZSTAN

The paper discusses the possibility of solar energy using in the Republic of Kyrgyzstan (RK) for the purpose of electricity distribution. The data sources analysis for the calculation of solar resources was conducted. Due to the scarcity of solar radiation stations on the territory of the RK, international thematic databases containing sufficient information for resource assessment and design were considered. These databases contain the results of long-term ground-based measurements, mathematical modeling and satellite observations. The paper justifies the compliance of a global database with public access NASA SSE to the problem of solar energy resources estimation, and estimates the gross capacity for the territory of the Kyrgyzstan. The authors propose their method of initial evaluation of performance, capital cost and footprint for network photovoltaic plant. The calculations are performed based on monthly averages of daily insolation and the average temperature. To account for the effect of ambient temperature on the output of PV modules, the paper considers two scenarios: the maximum and minimum daily mean ambient temperatures in each month. Evaluate the performance and the cost of electricity are made for plants with a capacity of 5 MW in the case of placing it near the cities of Bishkek and Osh (northern and central part of the RK). At the same time the authors carry out a comparative analysis of the results obtained for several types of silicon photovoltaic modules on the market today: monocrystalline, multicrystalline and the thin film. It is shown that the maximum performance of the network station is provided at an inclination of modules close to the latitude. The temperature dependence of the module characteristics makes the largest contribution to the change in productivity in the summer. The calculations also show that the multicrystalline photovoltaic modules are optimal in terms of price and quality for selected conditions.

Automatic part localization in a CNC machine coordinate system by means of 3D scans

Due to the rough nature of surfaces produced by current additive metal processes, a deviation between the nominal and actual pose of the part arises when fixturing in an NC machine. Modern 3D scanning systems are capable of generating high density measurements that may be used to localize the part and compensate for these errors; but require that scan data be transformed from the scanner to the CNC coordinate systems. In this work, precisely located fiducial features are automatically detected in the scan data and used to compute the pose of the scanner. This information is used to register each scan to the CNC machine space, and thereby create a model of the workpiece as-built and as-mounted in the machine, for use in process planning and localization. An implementation of the system was built and tested against a machined part that was offset to simulate uncertain position and orientation. The initial performance evaluation of the system indicates that it is capable of successfully registering surfaces to the machine coordinate system with accuracy in line with the scanner performance specification.

A web based cross-platform application for teleconsultation in radiology

The growing complexity of radiologic examinations and interventional procedures requires frequent exchange of knowledge. Consequently a simple way to share and discuss patient images between radiology experts and with colleagues from other medical disciplines is needed. Aims of this work were the development and initial performance evaluation of a fast and user friendly, platform independent teleconsultation system for medical imaging. A local back end system receives DICOM images and generates anonymized JPEG files that are uploaded to an internet webserver. The front end running on that webserver comprises an image viewer with a specially developed pointer element for indicating findings to collaborative partners. The front end that uses only standard web technologies works on a variety of different platforms, mobile devices and desktop computers. Images can be accessed by simply calling up a special internet address in a web browser that may be exchanged between users (e.g. via email). A speed evaluation of the system showed good results: For example the preparation and upload of a standard head CT took less than 21 seconds. The data volume of the same series and the viewer application could be transferred to a mobile phone in less than 42 seconds via a UMTS network or in less than 3 seconds via a HSPA network. The presented system with its minimal hard- and software requirements, its simplicity and platform independence might be a promising tool in the increasingly important area of teleconsultation.

Realtime voice activity and pitch modulation for laryngectomy transducers using head and facial gestures

Individuals who have undergone laryngectomy often rely on handheld transducers (i.e., the electrolarynx) to excite the vocal tract and produce speech. Widely used electrolarynx designs are limited, in that they require manual control of voice activity and pitch modulation. It would be advantageous to have an interface that requires less training, perhaps using the remaining, intact speech production system as a scaffold. Strong evidence exists that aspects of head motion and facial gestures are highly correlated with gestures of voicing and pitch. Therefore, the goal of project MANATEE is to develop an electrolarynx control interface which takes advantage of those correlations. The focus of the current study is to determine the feasibility of using head and facial features to accurately and efficiently modulate the pitch of speaker's electrolarynx in real time on a mobile platform using the built-in video camera. A prototype interface, capable of running on desktop machines and compatible Android devices, is implemented using OpenCV for video feature extraction and statistical prediction of the electrolarynx control signal. Initial performance evaluation is promising, showing pitch prediction accuracies at double the chance-level baseline, and prediction delays well below the perceptually-relevant, ~50 ms threshold.

Design and performance of A 3He-free coincidence counter based on parallel plate boron-lined proportional technology

Thermal neutron counters utilized and developed for deployment as non-destructive assay (NDA) instruments in the field of nuclear safeguards traditionally rely on 3He-based proportional counting systems. 3He-based proportional counters have provided core NDA detection capabilities for several decades and have proven to be extremely reliable with range of features highly desirable for nuclear facility deployment. Facing the current depletion of 3He gas supply and the continuing uncertainty of options for future resupply, a search for detection technologies that could provide feasible short-term alternative to 3He gas was initiated worldwide. As part of this effort, Los Alamos National Laboratory (LANL) designed and built a 3He-free full scale thermal neutron coincidence counter based on boron-lined proportional technology. The boron-lined technology was selected in a comprehensive inter-comparison exercise based on its favorable performance against safeguards specific parameters. This paper provides an overview of the design and initial performance evaluation of the prototype High Level Neutron counter—Boron (HLNB). The initial results suggest that current HLNB design is capable to provide ~80% performance of a selected reference 3He-based coincidence counter (High Level Neutron Coincidence Counter, HLNCC). Similar samples are expected to be measurable in both systems, however, slightly longer measurement times may be anticipated for large samples in HLNB. The initial evaluation helped to identify potential for further performance improvements via additional tailoring of boron-layer thickness.

CFD Study of Tidal Current Turbine Shroud for Initial Design Evaluation

CFD simulation of a tidal current turbine shroud was performed using Ansys FLUENT commercial code and comparison was made with experimental data. The simulation result obtained was in good agreement with the experimental data. The coefficient of velocity, Cv was in the range of approximately 1.2 to 1.4 for both simulation and experiment. The present study gave useful information on the viability of CFD simulation for the initial evaluation of shroud design performance.

Initial Performance Evaluation of a Gridded Radio Frequency Ion Thruster

Helicon plasma sources are devices that are capable of efficiently producing high-density plasmas. There is growing interest in using a helicon plasma source in space propulsion as a replacement to the direct current plasma discharge in ion engines. A radio frequency ion engine is developed that combines a helicon plasma source with electrostatic grids and a magnetically shielded anode. Thruster performance evaluation includes estimation of the discharge plasma ion density and electron temperature and measurement of the plume current density, grid currents, and thrust. The radio frequency ion engine is tested across the following operating parameter ranges: 343–600 W radio frequency power, 50–250 G magnetic field strength, argon flow rate, and 100–600 V discharge voltage range at an operating pressure of , discharge ion density and electron temperature range and 5.4–9.9 eV, respectively. Maximum beam current extracted is 120 mA at a 600 V discharge and is primarily limited by ion impingement on the grids due to insufficient grid potentials. The maximum measured thrust is 2.77 mN with an average uncertainty of . Further optimization of the thruster operating conditions and grid assembly can improve thruster performance.

Rapid and inexpensive body fluid identification by RNA profiling-based multiplex High Resolution Melt (HRM) analysis.

Positive identification of the nature of biological material present on evidentiary items can be crucial for understanding the circumstances surrounding a crime. However, traditional protein-based methods do not permit the identification of all body fluids and tissues, and thus molecular based strategies for the conclusive identification of all forensically relevant biological fluids and tissues need to be developed. Messenger RNA (mRNA) profiling is an example of such a molecular-based approach. Current mRNA body fluid identification assays involve capillary electrophoresis (CE) or quantitative RT-PCR (qRT-PCR) platforms, each with its own limitations. Both platforms require the use of expensive fluorescently labeled primers or probes. CE-based assays require separate amplification and detection steps thus increasing the analysis time. For qRT-PCR assays, only 3-4 markers can be included in a single reaction since each requires a different fluorescent dye. To simplify mRNA profiling assays, and reduce the time and cost of analysis, we have developed single- and multiplex body fluid High Resolution Melt (HRM) assays for the identification of common forensically relevant biological fluids and tissues. The incorporated biomarkers include IL19 (vaginal secretions), IL1F7 (skin), ALAS2 (blood), MMP10 (menstrual blood), HTN3 (saliva) and TGM4 (semen). The HRM assays require only unlabeled PCR primers and a single saturating intercalating fluorescent dye (Eva Green). Each body-fluid-specific marker can easily be identified by the presence of a distinct melt peak. Usually, HRM assays are used to detect variants or isoforms for a single gene target. However, we have uniquely developed duplex and triplex HRM assays to permit the simultaneous detection of multiple targets per reaction. Here we describe the development and initial performance evaluation of the developed HRM assays. The results demonstrate the potential use of HRM assays for rapid, and relatively inexpensive, screening of biological evidence.