Comparing seasonal streamflow forecast systems for management of a fresh water reservoir in the Netherlands

For efficient management of the Dutch surface water reservoir Lake IJssel, (sub)seasonal forecasts of the water volumes going in and out of the reservoir are potentially of great interest. Here, streamflow forecasts were analyzed for the river Rhine at Lobith, which is partly routed through the river IJssel, the main influx into the reservoir. We analyzed multiple seasonal forecast data sets derived from EFAS, E-HYPE and HTESSEL, which differ in their underlying hydrological formulation, but are all forced with similar input from the ECMWF SEAS5 meteorological forecasts. We post-processed the streamflow forecasts using quantile matching (QM) and analyzed several forecast quality metrics. Forecast performance was assessed based on the available reforecast period, as well as on individual summer seasons. QM increased forecast skill for nearly all metrics evaluated. Particularly HTESSEL, a land surface scheme that is not optimized for hydrology, needed the largest correction. Averaged over the reforecast period, forecasts were skillful for the longest lead times in spring and early summer. For this period, E-HYPE showed the highest skill; Later in summer, however, skill deteriorated after 1–2 months. When investigating specific years with either low or high flow conditions, forecast skill increased with the extremity of the event. Although raw forecasts for both E-HYPE and EFAS were more skilful than HTESSEL, bias correction based on QM can significantly reduce the difference. In operational mode, the three forecast systems show comparable skill. In general, dry conditions can be forecasted with high success rates up to three months ahead, which is very promising for successful use of Rhine streamflow forecasts in downstream reservoir management.

Analysis of MEA’s durability under Accelerated Stress Tests that mimic realistic automotive operations

This work aims at studying MEA’s ageing under single operational “mode” accelerated stress tests (AST), that were specifically designed to replicate under hydrogen/air feeding the main stressors of realistic operations in the automotive sector. A methodology for developing AST is here presented and preliminary results about the activity included. In particular, low power and high power functioning have been mimicked in a Zero-Gradient hardware, which allows a reliable materials comparison. Quantities, measurable in-situ and operando, have been tracked during ageing, like cell power, polarization curves, Pt active area, oxygen mass transport resistance, Electrochemical Impedance Spectra. The final objective is to clarify the underlying ageing mechanisms and assess the contribution of each specific operation to the MEA lifetime, focusing in particular on the cathode catalyst layer durability. Moreover, the rate of voltage loss for the new ASTs has been successfully correlated to the degradation observed under a complete driving cycle protocol.

OPERATIONAL BEHAVIOUR OF AN OFFSHORE MULTIPURPOSE SUPPORT VESSEL IN THE EASTERN MEDITERRANEAN SEA

The objective of this work is to analyse the operational behaviour of an offshore multipurpose support vessel designed to operate in the Eastern Mediterranean Sea. First, the seakeeping analysis is performed in a regular wave condition for different heading angles estimating heave and pitch motions through the strip theory. After that, the effects of the vertical acceleration on the bow, occurrence of slamming or hydrodynamic impact of the hull on the surface of the water; wetted deck, occurrence or invasion of water on the deck of the vessel and propeller emersion, motion sickness and wave-induced additional resistance are analysed. The present analysis is extended in an irregular sea condition, and the estimated seakeeping criteria are compared to the acceptable levels. In defining the most suitable operational mode of the offshore support vessels, multi-criteria decision techniques and probabilistic approach are employed to perform an adequate evaluation of the seakeeping performance accounting for different hazardous events through the service life.

Automated Workflow Based on Transient, Multiphase Technology Improves Well Control Planning Efficiency and Reduces Risk

The use of automated workflows for engineering calculations is significantly improving the efficiency of modern well planning systems. Current automated well control solutions are at large limited to single bubble considerations. Transient, multiphase technology has proven to be more accurate and reliable for well control planning, but it has been too complex to automate and integrate into automated engineering systems. The objective of this work is to improve well control planning efficiency by using an automated workflow that enables integration of transient multiphase technology into modern well-planning systems. The workflow is based around an advanced multiphase engine that covers all relevant physical processes in the wellbore including transient temperature and acceleration. The model has an accurate equations-of-state- (EOS) based pressure-volume-temperature (PVT) model with compositional tracking that, in combination with the transient temperature, can accurately predict the transition from dissolved to free gas - a key parameter in the development of a kick. The workflow is based on Driller's method and has been automated with a controller network that moves the simulation through the distinct phases of the driller's first circulation without any interaction from the user. High-performance cloud computing ensures the workflow performance. The drilling industry has focused on risk reductions after the Deepwater Horizon (BSSE 2010) accident. But the well-control risk is still high. In Norway, the reported incidents indicate a flat or increasing trend. Geological uncertainties and inaccurate mud density (static and circulating) have been identified as root causes for the majority of the reported incidents. Transient multiphase models are reducing well-control risk by accurately modeling downhole variations in fluid pressure as a function of operational mode, fluids, influx type, geometry, water depth, and pressure and temperature conditions. Such models have been regarded as expert tools because of the complexity and numerically demanding simulations. The automated workflow enables a well control engineer to run accurate multiphase simulations with the same user effort as single bubble kick tolerance tools. In special cases where more sensitivities are required, it is easy to transfer the project to the expert mode - where the automated simulation can be finetuned.

Exploring the limits of conventional small-scale CHO fed-batch for accelerated on demand monoclonal antibody production

In the field of therapeutic antibody production, diversification of fed-batch strategies is flourishing in response to the market demand. All manufacturing approaches tend to follow the generally accepted dogma of increasing titer since it directly increases manufacturing output. While titer is influenced by the biomass (expressed as IVCD), the culture time and the cell-specific productivity (qP), we changed independently each of these parameters to tune our process strategy towards adapted solutions to individual manufacturing needs. To do so, we worked separately on the increase of the IVCD as high seeding fed-batch capacity. Yet, as intensified fed-batch may not always be possible due to limited facility operational mode, we also separately increased the qP with the addition of specific media additives. Both strategies improved titer by 100% in 14 days relative to the standard fed-batch process with moderate and acceptable changes in product quality attributes. Since intensified fed-batch could rival the cell-specific productivity of a conventional fed-batch, we developed novel hybrid strategies to either allow for acceptable seeding densities without compromising productivity, or alternatively, to push the productivity the furthest in order to reduce timelines.

Spectral and correlation analysis of microturbulences in the spherical Globus-M/M2 tokamaks

Results of the studies on turbulences carried out on the Globus-M2 and Globus-M tokamaks are presented. The main focus was on the analysis of the data obtained using Doppler backscattering method (DBS). The developed codes for the analysis of DBS signals allowed to study the effects of turbulences on the operational mode of the tokamak. A description of the data processing codes is also included. The analysis performed indicates the suppression of turbulence and the formation of a velocity shear during the L-H transition. It was also successfully used to study density fluctuations during and between edge localized modes (ELMs). Spectral and correlation analysis also led to the discovery of limit-cycle oscillations (LCO) and quasi coherent fluctuations (QCFs) during the I-phase.

Design and Fabrication of a Printed Tri-Band Antenna for 5G Applications Operating Across Ka-, and V-Band Spectrums

In this paper, an umbrella-shaped patch antenna for future millimeter-wave applications for the 5G frequency band is presented. The proposed antenna resonates at multiple frequency bands, i.e., 28 GHz, 38 GHz, and 55 GHz (V-band) that have been globally allocated for 5G communications systems. The proposed antenna is designed using Rogers RT/duroid 5870, with a relative permittivity, loss tangent and thickness of 2.33 mm, 0.0012 mm and 0.79 mm, respectively. The antenna has an overall size of 8 mm × 8 mm which correspond to 0.7 λ × 0.7 λ, where λ is free space wavelength at the lowest resonance. Moreover, the wide bandwidth, high gain and tri band operational mode is achieved by introducing two stubs to the initial design. The antenna prototype was fabricated and validated experimentally. The comparison of the simulated and measured results demonstrates a good correlation. Additionally, the comparative analysis with state of the art work demonstrates that the proposed antenna offers compact size, simple geometrical configuration, wide bandwidth, high gain, and radiation efficiency which makes the proposed antenna a potential candidate for compact smart 5G devices.

Hybrid Piezo/Magnetic Electromechanical Transformer

This paper presents a hybrid electromechanical transformer that passively transfers electrical power between galvanically isolated ports by coupling electrodynamic and piezoelectric transducers. The use of these two complementary electromechanical transduction methods along with a high-Q mechanical resonance affords very large transformations of voltage, current, or impedance at particular electrical frequencies. A chip-size prototype is designed, simulated, fabricated, and experimentally characterized. The 7.6 mm 7.6 mm 1.65 mm device achieves an open-circuit voltage gain of 31.4 and 48.7 when operating as a step-up transformer at 729.5 Hz and 1015 Hz resonance frequencies, respectively. When operating as a step-down transformer, the resonance frequencies and the corresponding voltage gains are 728 Hz, 1002 Hz, and 0.0097, 0.0128, respectively. In one operational mode, the system shows a minimum power dissipation of only 0.9 µW corresponding to a power conversion efficiency of 11.8%.