Field Setup Research Articles

Efficiency of a novel non-monotonic segmented leaf sequence delivery of Varian MLC for non-split IMRT fields.

Development of bidirectional non-monotonic segmented leaf sequence (NSLS) MLC delivery technique compatible with Varian MLC for non-split IMRT fields reducing total monitor units (TotalMU) and the number of segments (NS) simultaneously and assessment of its efficiency using a plan scoring index (PSI). The optimal fluence of IMRT plans of ten patients of lung carcinoma, calculated using Eclipse TPS version 11.0 (Varian Medical Systems, Palo Alto, CA, USA), was used to generate the segmented MLC fields using our newly developed equally spaced (ES) reducing level and NSLS algorithms in MATLAB® version 2011b for 6-10 intensity levels. These MLC fields were imported into the plans with the same field setup and the final dose was recalculated. The results were compared with those of commercially available multiple static segments (MSS) leaf motion calculation (LMC) algorithm and few previously published algorithms. Plan scoring index (PSI) and degree of modulation (DoM) was calculated to compare the quality of different plans for the same patient. The average differences in TotalMU and NS with respect to MSS algorithm are -3.80% and -14.28% for the NSLS algorithm, respectively. The calculated average PSI and DoM is 0.75, 2.51 and 0.91, 2.41 for the MSS and NSLS algorithms, respectively. IMRT plans generated using the NSLS algorithm resulted in the best PSI, DoM values among all the leaf sequencing algorithms. Our proposed NSLS algorithm allows bidirectional delivery in Varian medical linear accelerator which is not commercially available. NSLS algorithm is efficient in reducing the TotalMU and NS with equivalent plan quality as that of MSS.

Multivariate Analysis of Open Field Exploration Identifies Latent Spatial and Social Behavioral Axes in Domestic Dogs.

Recent methodological advances in studying large scale animal movements have let researchers gather rich datasets from behaving animals. Often collected in small sample sizes due to logistical constraints, these datasets are however, ideal for multivariate explorations into behavioral complexity. In behavioral studies of domestic dogs, although automated data loggers have recently seen increasing use, a comprehensive framework to identify complex behavioral axes is lacking. Dog behavioral studies frequently rely on subjective ratings, despite demonstrable evidence that these are insufficient for identifying behavioral variables. Taking advantage of dogs’ innate running abilities and readily available GPS data loggers, we extracted latitude-longitude coordinates from running dogs in a large field setup. By extracting multiple variables from each logged coordinate, we generated a complex dataset from limited numbers of dog runs. Individual variables were successful in classifying aerobic competence, social awareness, and different exploratory patterns of dogs. Multivariate analyses identified latent features in movement patterns of dogs which were primarily comprised of two behavioral axes: spatial acuity and social awareness. Individual dogs were then behaviorally classified into independent clusters through unsupervised learning. Interestingly, even though field dogs clustered primarily with each other in varying degrees of energetic exploration and handler focus, some house pets displayed moderately high exploration abilities as well. We expect our proof of principle quantitative pipeline to provide a robust framework for behavioral classification, generating case-control clusters based solely on complex behavioral axes, and greatly benefiting genetic association studies of dog behavior.

Genetic Basis of Maize Resistance to Multiple Insect Pests: Integrated Genome-Wide Comparative Mapping and Candidate Gene Prioritization.

Several species of herbivores feed on maize in field and storage setups, making the development of multiple insect resistance a critical breeding target. In this study, an association mapping panel of 341 tropical maize lines was evaluated in three field environments for resistance to fall armyworm (FAW), whilst bulked grains were subjected to a maize weevil (MW) bioassay and genotyped with Diversity Array Technology’s single nucleotide polymorphisms (SNPs) markers. A multi-locus genome-wide association study (GWAS) revealed 62 quantitative trait nucleotides (QTNs) associated with FAW and MW resistance traits on all 10 maize chromosomes, of which, 47 and 31 were discovered at stringent Bonferroni genome-wide significance levels of 0.05 and 0.01, respectively, and located within or close to multiple insect resistance genomic regions (MIRGRs) concerning FAW, SB, and MW. Sixteen QTNs influenced multiple traits, of which, six were associated with resistance to both FAW and MW, suggesting a pleiotropic genetic control. Functional prioritization of candidate genes (CGs) located within 10–30 kb of the QTNs revealed 64 putative GWAS-based CGs (GbCGs) showing evidence of involvement in plant defense mechanisms. Only one GbCG was associated with each of the five of the six combined resistance QTNs, thus reinforcing the pleiotropy hypothesis. In addition, through in silico co-functional network inferences, an additional 107 network-based CGs (NbCGs), biologically connected to the 64 GbCGs, and differentially expressed under biotic or abiotic stress, were revealed within MIRGRs. The provided multiple insect resistance physical map should contribute to the development of combined insect resistance in maize.

Dust vortex flow analysis in weakly magnetized plasma

Analysis of driven dust vortex flow is presented in a weakly magnetized plasma. The 2D hydrodynamic model is applied to the confined dust cloud in a non-uniform magnetic field in order to recover the dust vortex flow driven in a conservative force field setup, in the absence of any non-conservative fields or dust charge variation. Although the time independent electric and magnetic fields included in the analysis provide conservative forcing mechanisms, when a drift based mechanism, recently observed in a dusty plasma experiment by M. Puttscher and A. Melzer [Phys. Plasmas 21, 123704 (2014)] is considered, the dust vortex flow solutions are shown to be recovered. We have examined the case where a purely ambipolar electric field, generated by polarization produced by the electron E×B drift, drives the dust flow. A sheared E×B drift flow is facilitated by the magnetic field gradient, driving the vortex flow in the absence of ion drag. The analytical stream-function solutions have been analyzed with varying magnetic field strengths, gradients, and kinematic viscosities of the dust fluid. The effect of the B field gradient is analyzed which contrasts that of the E field gradient present in the plasma sheath.

Peanut production through innovative water management strategies

Background/Objectives: A study on enhancing peanut production through drip irrigation (DI) technology was conducted to increase the productivity and profitability of peanut production in the Ilocos region, Philippines. It sought to develop irrigation management strategies suitable for peanut. Methods/Statistical analysis: Decision Support System for Agrotechnology Transfer (DSSAT) simulation was done, and field validation was conducted to achieve the objectives. The simulation activity led to the determination of the top three promising drip irrigation management schemes suitable for peanut production, which were then field validated through actual field set-up in three different locations. The best scheme (DI S9 410mm) was then pilot-tested at the farmers\' field and compared with Farmers\' Practice (FP) d using t-test. Findings: Using the DI scheme, dry pod yield was increased from 1.59Tha-1to 2.09Tha-1 or 31.45% increase as compared to the farmer\'s practice. This result is a little higher than the target increase in yield of 30%. Findings indicate that the DI is a much better method than FP, increasing the dry pod yield to as much as 70.21% during the dry season. Yield increase could be attributed to more even application of water and less water stress. On the other hand, water productivity was only increased by around 16% due to farmers\' limited water application. In terms of seed quality based on seed size, DI and FP are comparable. Results the economic analysis showed that yield of peanut under DI were higher by about 0.84Tha-1 to 1.16Tha-1 as compared to FP with a Return of Investment (ROI) of 0.25. In the long run, the profitability of DI could be improved through water productivity and yield improvements. Water savings was not a factor in profitability due to under-irrigation by farmers. Novelty/Applications: The use of DI technology with the developed irrigation scheme substantially contributed to the goal of increasing the productivity of and profitability of peanut. It is especially useful for areas with limited water supply for irrigation. Keywords: Drip irrigation; peanut; water productivity; water savings; DSSAT simulation

Shortening delivery times for intensity-modulated proton therapy by reducing the number of proton spots: an experimental verification

Delivery times of intensity-modulated proton therapy (IMPT) can be shortened by reducing the number of spots in the treatment plan, but this may affect clinical plan delivery. Here, we assess the experimental deliverability, accuracy and time reduction of spot-reduced treatment planning for a clinical case, as well as its robustness. For a single head-and-neck cancer patient, a spot-reduced plan was generated and compared with the conventional clinical plan. The number of proton spots was reduced using the iterative ‘pencil beam resampling’ technique. This involves repeated inverse optimization, while adding in each iteration a small sample of randomly selected spots and subsequently excluding low-weighted spots until plan quality deteriorates. Field setup was identical for both plans and comparable dosimetric quality was a prerequisite. Both IMPT plans were delivered on PSI Gantry 2 and measured in water, while delivery log-files were used to extract delivery times and reconstruct the delivered dose via Monte-Carlo dose calculations. In addition, robustness simulations were performed to assess sensitivity to machine inaccuracies and errors in patient setup and proton range. The number of spots was reduced by 96% (from 33 855 to 1510 in total) without compromising plan quality. The spot-reduced plan was deliverable on our gantry in standard clinical mode and resulted in average delivery times per field being shortened by 46% (from 51.2 to 27.6 s). For both plans, differences between measured and calculated dose were within clinical tolerance for patient-specific verifications and Monte-Carlo dose reconstructions were in accordance with clinical experience. The spot-reduced plan was slightly more sensitive to machine inaccuracies, but more robust against setup and range errors. In conclusion, for an example head-and-neck case, spot-reduced IMPT planning provided a deliverable treatment plan and enabled considerable shortening of the delivery time (∼50%) without compromising plan quality or delivery accuracy, and without substantially affecting robustness.

Response of SDO/HMI Observables to Heating of the Solar Atmosphere by Precipitating High-energy Electrons

Abstract We perform an analysis of the line-of-sight (LOS) observables of the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) for models of the solar atmosphere heated by precipitating high-energy electrons during solar flares. The radiative hydrodynamic (RADYN) flare models are obtained from the F-CHROMA database. The Stokes profiles for the Fe 6173 Å line observed by SDO/HMI are calculated using the radiative transfer code RH1.5D, assuming statistical equilibrium for atomic level populations, and imposing uniform background vertical magnetic fields of various strengths. The SDO/HMI observing sequence and LOS data processing pipeline algorithm are applied to derive the observables (continuum intensity, line depth, Doppler velocity, LOS magnetic field). Our results reveal that the strongest deviations of the observables from the actual spectroscopic line parameters are found for the model with a total energy deposited of E total = 1.0 × 1012 erg cm−2, injected with a power-law spectral index of δ = 3 above a low-energy cutoff of E c = 25 keV. The magnitudes of the velocity and magnetic field deviations depend on the imposed magnetic field, and can reach 0.35 km s−1 for LOS velocities, 90 G for LOS magnetic field, and 3% for continuum enhancement for the 1000 G imposed LOS magnetic field setup. For E total ≥ 3.0 × 1011 erg cm−2 models, the velocity and magnetic field deviations are most strongly correlated with the energy flux carried by ∼50 keV electrons, and the continuum enhancement is correlated with the synthesized ∼55–60 keV hard X-ray photon flux. The relatively low magnitudes of perturbations of the observables and absence of magnetic field sign reversals suggest that the considered RADYN beam heating models augmented with the uniform vertical magnetic field setups cannot explain the strong transient changes found in the SDO/HMI observations.

A Technical Evaluation of Lidar‐Based Measurement of River Water Levels

AbstractMeasuring river water level (stage) is key for a variety of applications including discharge estimation and flood prediction. Although a variety of in situ and noncontact methods are available, there is an urgent need for new and more cost‐efficient methods. Rapid technological progress has accelerated the use of noncontact methods and development of time‐of‐flight distance sensors. Among available techniques, the use of lidar for distance measurement is promising because of its low cost, high energy efficiency, and small measurement footprint. However, lidar has rarely been used to measure water levels. Here we test a near‐infrared (905 nm) lidar sensor to determine its suitability for stage measurements under a range of environmental conditions. Using different laboratory and field setups, we assess sensor performance as a function of measurement distance, surface roughness, air temperature, water turbidity, and measurement angle. Despite the low reflectivity of water for infrared radiation, we find that the tested sensor is able to take measurements under all tested conditions, up to an incidence angle of ∼40°. The accuracy of the sensor is within the technical specifications of the device and is characterized by a relative error of around 0.1%. We find a strong dependence of the accuracy on sensor temperature, which we attribute to suboptimal internal compensation of the electronics. The precision of the sensor decreases with increasing measured distance and increases with surface roughness of the water body. We did not find any significant impact of water turbidity on the measurements.

Track propagation for different detector and magnetic field setups in Acts

Track finding and fitting are among the most complex parts of event reconstruction in high-energy physics, and usually dominate the computing time in a high luminosity environment. A central part of track reconstruction is the transport of a given track parametrisation (i.e. the parameter estimation and associated covariance matrices) through the detector, respecting the magnetic field setup and the traversed detector material. While track propagation in a sparse environment (e.g. tracking detector with layers) can be sufficiently well approximated by considering discrete interactions at several positions, the propagation in a material dense environment (e.g. calorimeters) is better served by a continuous application of material effects. Recently, a common tracking software project (Acts), originally from the Common Tracking code of the ATLAS experiment, has been developed in order to preserve the algorithmic concepts from the LHC start-up era and prepare them for the high luminosity era of the LHC and beyond. The software is designed in an abstract, detector independent way and prepared to allow highly parallelised execution of all involved software modules, including magnetic field access and alignment conditions. Therefore the propagation algorithm needs to be both flexible and adjustable. The implemented solution using a fourth order Runge-Kutta-Nyström integration and its extension with continuous material integration and eventual time propagation is presented and the navigation through different geometry setups involving different environments is demonstrated.

Autonomous Mobile Ground Control Point Improves Accuracy of Agricultural Remote Sensing through Collaboration with UAV

Ground control points (GCPs) are critical for agricultural remote sensing that require georeferencing and calibration of images collected from an unmanned aerial vehicles (UAV) at different times. However, the conventional stationary GCPs are time-consuming and labor-intensive to measure, distribute, and collect their information in a large field setup. An autonomous mobile GCP and a collaboration strategy to communicate with the UAV were developed to improve the efficiency and accuracy of the UAV-based data collection process. Prior to actual field testing, preliminary tests were conducted using the system to show the capability of automatic path tracking by reducing the root mean square error (RMSE) for lateral deviation from 34.3 cm to 15.6 cm based on the proposed look-ahead tracking method. The tests also indicated the feasibility of moving reflectance reference panels successively along all the waypoints without having detrimental effects on pixel values in the mosaicked images, with the percentage errors in digital number values ranging from −1.1% to 0.1%. In the actual field testing, the autonomous mobile GCP was able to successfully cooperate with the UAV in real-time without any interruption, showing superior performances for georeferencing, radiometric calibration, height calibration, and temperature calibration, compared to the conventional calibration method that has stationary GCPs.

Direct measurement of resistivity in destructive pulsed magnetic fields

A simple method for measuring electrical resistivity under destructive pulsed magnetic fields is presented. This method uses pick-up voltage as the power source to allow the measurement of the absolute value of resistivity in ultra-high magnetic fields above 100 T. The experimental setup and its operation are described in detail, and its performance is demonstrated using critical field measurements of thin-film FeSe0.5Te0.5 samples. Possible scientific applications of this setup in high magnetic fields as well as in any other environment with a high field sweep rate are also discussed.

Configuration Requirements for Panoramic Terrestrial Laser Scanner Calibration Within a Point Field

A high-quality point field plays a crucial factor in scanner calibration. However, in most cases, efforts are made to find suitable algorithms and less attention is paid to establishing a point field. This letter focuses on the prediction and planning of quality point fields due to scanner calibration. We first propose specific criteria to assess whether the estimated calibration parameters are accurate enough for panoramic scanners. We relate a statistical bound for the unknown estimate deviations to the standard deviations of the scanner’s raw measurements. We then apply the criteria and configuration requirements as the basic building blocks to design a point field and scanner setup plan to determine a subset of frequently used additional parameters (APs) to calibrate an indoor field with separately measured target coordinates. The provided strategy is the local optimal solution, as tested using Monte Carlo simulations and real calibration tasks.

Automatic generation of three-dimensional dose reconstruction data for two-dimensional radiotherapy plans for historically treated patients.

Performing large-scale three-dimensional radiation dose reconstruction for patients requires a large amount of manual work. We present an image processing-based pipeline to automatically reconstruct radiation dose. The pipeline was designed for childhood cancer survivors that received abdominal radiotherapy with anterior-to-posterior and posterior-to-anterior field set-up. First, anatomical landmarks are automatically identified on two-dimensional radiographs. Second, these landmarks are used to derive parameters to emulate the geometry of the plan on a surrogate computed tomography. Finally, the plan is emulated and used as input for dose calculation. For qualitative evaluation, 100 cases of automatic and manual plan emulations were assessed by two experienced radiation dosimetrists in a blinded comparison. The two radiation dosimetrists approved 100%/100% and 92%/91% of the automatic/manual plan emulations, respectively. Similar approval rates of 100% and 94% hold when the automatic pipeline is applied on another 50 cases. Further, quantitative comparisons resulted in on average difference in plan isocenter/borders, and in organ mean dose (prescribed dose: 14.4Gy) calculated from the automatic and manual plan emulations. No statistically significant difference in terms of dose reconstruction accuracy was found for most organs at risk. Ultimately, our automatic pipeline results are of sufficient quality to enable effortless scaling of dose reconstruction data generation.

Prevention of transmission of leprosy: The current scenario.

With the worldwide implementation of WHO multidrug therapy in the 1980s, the global burden of leprosy has decreased. However, the annual new case detection rate around the world has remained nearly static over the past decade with India, Brazil, and Indonesia contributing the majority of these new cases. This has been attributed to the ongoing transmission of Mycobacterium leprae from existing untreated cases and partly to the intensive new case detection programs operative in endemic areas. The WHO has called for a "global interruption of transmission of leprosy by 2020". Targeted chemoprophylaxis of contacts may help bring down the number of new cases. The single-dose rifampicin currently in use for post-exposure prophylaxis (PEP) has limitations and so newer antileprosy drugs and regimens have been trialed for chemoprophylaxis. BCG re-vaccination in combination with chemoprophylaxis for the prevention of leprosy transmission has not been very encouraging. The use of the anti-phenolic glycolipid-1 (PGL-1) antibody test to detect subclinical cases and administer targeted chemoprophylaxis was unsuccessful owing to its low sensitivity and technical difficulties in a field setup. There is a pressing need for newer multidrug chemoprophylactic regimens using second-line antileprosy drugs. The Netherlands Leprosy Relief has proposed an enhanced PEP++ regimen. A simple but highly sensitive and specific serological test to detect subclinical cases at the field level needs to be developed. Although there are a number of challenges in the large-scale implementation of strategies to halt leprosy transmission, it is important to overcome these in order to move towards a "leprosy-free world."

Transient Thermal Behaviors of Ultra-Supercritical Steam Turbine Control Valves During the Cold Start Warm-Up Process: Conjugate Heat Transfer Simulation and Field Data Validation

Abstract Transient thermal behaviors of ultra-supercritical steam turbine control valves during the cold start warm-up process of steam turbine systems were comprehensively studied using conjugate heat transfer (CHT) simulation. The geometrical configurations and boundary conditions used in simulation were identical to the field setup in a thermal power plant. The simulated temperature variations were first validated using measurements by the flush-mounted thermocouples inside the solid valve bodies. The CHT simulation implementing the shear stress transport (SST) turbulence model demonstrated good agreement with the field data, and the overall numerical errors were below 10%; however, the numerical errors of the simulation, which used empirical heat transfer coefficients at the fluid–solid interfaces, reached 40%. The determined temperature differences between the cold valve bodies with the hot steam flow decreased significantly. Specifically, the temperature differences along the inner wall surfaces of the valve bodies decreased to less than 50 °C. Further investigation of the transient heat flux distributions and Nusselt number distributions confirmed that the unsteady flow behaviors, such as the alternating oscillations of the annular wall-attached jet, the central reverse flow and the intermediate shear layer instabilities, enhanced the fluid–solid heat convection process and thus contributed to the warming up of the solid valve bodies.

Wave Measurements From Radar Tide Gauges

Currently the NOAA Center for Operational Oceanographic Products and Services (CO-OPS) is transitioning the primary water level sensor at most NWLON stations from an acoustic ranging system to microwave radars. With no stilling well and higher resolution of the open sea surface, microwave radars have the potential to provide real-time wave measurements at NWLON sites. Radar sensors at tide stations may offer a low cost, convenient way to increase nearshore wave observational coverage throughout the U.S. to support navigational safety and ocean research applications. Here we present the results of a field study comparing wave height measurements from four radar water level sensors with two different signal types (pulse and continuous wave swept frequency modulation-CWFM). A nearby bottom acoustic wave and current sensor is used as a reference. An overview of field setup and sensors will be presented, along with an analysis of performance capabilities of each radar sensor. The study includes results from two successive field tests. In the first, we examine the performance from a pulse microwave radar (WaterLOG H-3611) and two CWFM (Miros SM-94 and Miros SM-140). While both types of radars tracked significant wave height well over the test period, the pulse radar had less success resolving high frequency wind wave energy and showed a high level of noise towards the low frequency end of the spectrum. The pulse WaterLOG radar limitations were most apparent during times of high winds and locally developing seas. The CWFM radars demonstrated greater capability to resolve those higher frequency energies while avoiding low frequency noise. The initial field test results motivated a second field test, focused on the comparison of wave height measurements from two pulse radar water level sensors, the WaterLOG H3611 and the Endress and Hauser Micropilot FMR240. Significant wave height measurements from both radar water level sensors compared well to reference AWAC measurements over the test period, but once again the WaterLOG radar did not adequately resolve wind wave energy in high frequency bands and showed noise towards the low frequency end of the spectrum. The E+H radar demonstrated greater capability to measure waves.

Wave Measurements from Radar Tide Gauges.

Currently the NOAA Center for Operational Oceanographic Products and Services (CO-OPS) is transitioning the primary water level sensor at most NWLON stations from an acoustic ranging system to microwave radars. With no stilling well and higher resolution of the open sea surface, microwave radars have the potential to provide real-time wave measurements at NWLON sites. Radar sensors at tide stations may offer a low cost, convenient way to increase nearshore wave observational coverage throughout the U.S. to support navigational safety and ocean research applications. Here we present the results of a field study comparing wave height measurements from four radar water level sensors with two different signal types (pulse and continuous wave swept frequency modulation-CWFM). A nearby bottom acoustic wave and current sensor is used as a reference. An overview of field setup and sensors will be presented, along with an analysis of performance capabilities of each radar sensor. The study includes results from two successive field tests. In the first, we examine the performance from a pulse microwave radar (WaterLOG H-3611) and two CWFM (Miros SM-94 and Miros SM-140). While both types of radars tracked significant wave height well over the test period, the pulse radar had less success resolving high frequency wind wave energy and showed a high level of noise towards the low frequency end of the spectrum. The pulse WaterLOG radar limitations were most apparent during times of high winds and locally developing seas. The CWFM radars demonstrated greater capability to resolve those higher frequency energies while avoiding low frequency noise. The initial field test results motivated a second field test, focused on the comparison of wave height measurements from two pulse radar water level sensors, the WaterLOG H3611 and the Endress and Hauser Micropilot FMR240. Significant wave height measurements from both radar water level sensors compared well to reference AWAC measurements over the test period, but once again the WaterLOG radar did not adequately resolve wind wave energy in high frequency bands and showed noise towards the low frequency end of the spectrum. The E+H radar demonstrated greater capability to measure waves.

Spacer flashover in Gas Insulated Switchgear (GIS) with humid SF6 under different electrical stresses

Humid insulating gas (SF6) has been observed in a case study of 631 CB-bays of Gas Insulated Switchgear (GIS) operating under tropical conditions. The routine gas quality check in the case study reported that 20% of the non-Circuit Breaker enclosures have humidity above the value recommended by the IEEE and IEC standards. Therefore, an investigation into the flashover characteristics of a spacer in humid SF6 has been initiated in the High Voltage Laboratory of TU Delft, The Netherlands. The setup is a small model resembling the insulation system of a GIS with controlled parameters of humidity content and gas pressure. The electrical stresses in the test are AC, LI+, LI−, and SI with homogeneous, quasi-homogeneous-, and inhomogeneous field configurations. In general, the humidity does not influence the withstand strength of the spacer as long there is no condensation. When condensation occurred, the flashover voltage dropped by 28% during the test under AC at 2.6 bars, and by 38% during the test under LI+ at 2.5 bars; both with quasi-homogeneous field configuration. In the test with homogeneous field setup, the flashover voltage was dropped by 67% under LI+ at 3.4 bars. In our setup, it has also been observed that the flashover-drop due to condensation is higher than due to a 2-mm aluminum particle attached to the sample close to the high electric field region simulating the inhomogeneous field configuration.

A Scalable, Broadband, and Physics-Based Model for On-Chip Rectangular Spiral Inductors

A scalable, broadband, and physics-based compact model for on-chip spiral inductors with rectangular outline shape is demonstrated for the first time in this paper. A simple dc inductance model is developed based on the current sheet approximation. The reduction in inductance due to the flow of eddy current in a back metal plate is considered using the method of images. A three-ladder network is shown to be sufficient to accurately model skin effect caused due to the magnetic field setup at high frequencies. Geometry-dependent expression suitable for rectangular cross-sectional metal strips is presented to predict the proximity effect. Physics-based expression for the substrate capacitance is derived. The proposed model is also shown to have a good correlation in the presence of a patterned ground shield. The proposed model is verified across CMOS process parameters that affect the inductor performance, such as metal thickness, substrate resistivity, and substrate thickness. Furthermore, model accuracy is also validated across design parameters such as spiral width, spacing between turns, number of turns, and diameter. The model is shown to have a good agreement with both EM simulations and measurements.

Does winter oilseed rape grown from clothianidin-coated seeds affect experimental populations of mason bees and bumblebees? A semi-field and field study

Impacts of neonicotinoid-containing pesticides on pollinators have been heavily debated in recent years. While bees in the field get rarely exposed to lethal concentrations of neonicotinoids applied as seed coating, sublethal levels found in pollen and nectar may affect bee population development. We assessed a realistic and a worst-case scenario of clothianidin exposure to mason bees (Osmia bicornis) and bumblebees (Bombus terrestris) by conducting a small-scale field and semi-field experiment at sites planted with winter oilseed rape. Flight activity, mortality and population development (brood, colony strength and weight) of bumblebees and number of mason bee brood cells were assessed at three locations. We also analysed clothianidin residues in bee-collected pollen and nectar. We detected clothianidin at low concentrations in nectar and pollen; residues in pollen were higher than in nectar but did not exceed a maximum field concentration of 2.7 µg/kg for bumblebees and 4.7 µg/kg for mason bees. Exposure did not result in significant negative impacts on bumblebee colony development and potential reproductive success of mason bees in either semi-field or field setup. During exposure bumblebees in semi-field treatment tunnels were flying less actively than in control tunnels. Bumblebee colonies in treatment tunnels weighed more than control colonies at the end of the experiment. Our findings suggest that field-realistic exposure to oilseed rape grown from clothianidin-treated seeds (10 g clothianidin/kg seeds) poses little risks to mason bees, bumblebees and their population development. However, an impairment of flower visitation under a worst-case scenario may have implications for pollination services and crop production.