Operational feasibility study of stagnation pressure reaction control for a mid-caliber non-spinning projectile

Controlled,guided munitions can reduce dispersion in the shot,while providing the capability of engaging both stationary and maneuvering targets.The Netherlands Organisation for Applied Scientific Research has developed a fin-less control technology called Stagnation Pressure Reaction Control(SPRC)that takes stagnation pressure air and directs it sideways to control non-spinning projectiles.In a previous study,this technology was demonstrated at Mach 2 wind-tunnel conditions to achieve up to 1.5°controllable angle of incidence for a non-spinning,aerodynamically unstable projectile-like test object.In an operational scenario,the decelerating projectile will experience a decline in control force while the simultaneous forward shift of the center of pressure increases the need for control force.Furthermore,angles of incidence exceeding 1.5°will be experienced under realistic flight conditions,especially against maneuvering targets.This work addresses these challenges and presents an operational feasibility study for a practical application of SPRC in a non-spinning mid-caliber gun-launched projectile,using experiment data on control latency and force of the earlier study.It illustrates the combined effect of the control-and stability dynamics and underlines the potential of an SPRC projectile as a precisionoperation ammunition.This research revealed that SPRC technology can stabilize and control the hypothesized projectile in a direct fire scenario against stationary and maneuvering targets.

Cost projections for microwave plasma CO production using renewable energy

Successful deployment of renewable fuel production requires substantial cost reduction along the entire value chain of the underlying manufacturing routes.To improve their performance,renewable fuel production technologies should follow a cost-reducing learning curve.In this article,we adopt recent evidence that learning-by-doing is directly influenced by the technology unit size and explore three scenarios for microwave plasma CO_(2)conversion in which the learning rate varies between 10%,15%,and 20%.Our projections reveal that the total investments required to deploy this CO_(2)conversion technology at an exajoule scale decline from 83 down to 23 billion euros under a 10%increase in the value of the learning rate.The CO_(2) production costs in 2050 amount to 247–346€(2019)/t CO_(2),in which the range is determined by the value of the learning rate.Even under substantial learning until 2050 the levelized CO production cost is unlikely to become competitive with conventional natural gas-based CO_(2) production processes,except when a CO_(2)tax is applied of up to 150€(2019)/t CO_(2).To optimally exploit effects of learning-by-doing,we recommend developing several CO production technologies simultaneously with multiple unit sizes,so as to improve the chance of ultimately selecting the process with the highest learning rate.

Characterization of Spirooxazine and Spiropyran Hosted in Poly(Methyl Methacrylate) for Germicidal UV Source Indicator Application

A characterization of photophysical properties of 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3’-[3H]naphtha[2,1-b] [1,4]oxazine] (spirooxazine) and1’,3’-dihydro-1’,3’,3’-trimethyl-6-nitrospiro[2H-1-benzopyran-2,2’-(2H)-indole] (spiropyran) compounds hosted in poly(methyl methacrylate) (PMMA) was carried out. The parameters which influenced the photochromic behavior of both compounds were investigated. After ultraviolet (UV) irradiation, it was demonstrated that the temperature was the dominant factor which influenced the deactivation of both materials. For spiropyran, it was demonstrated that the process could be photo-induced with a certain wavelength which we have specified in this manuscript. It was also found that X-Ray did not affect the photo physical properties of spirooxazine and spiropyran. Finally, both materials could be used as low-cost germicidal UV indicators.

What determines walking of older people in their neighborhood?

Based on literature review and five focus groups, a model was analyzed describing individual, social environmental and physical environmental (perceived) determinants of walking by older people. Aim was to test whether these determinants were significantly associated with the duration of walking by older people (N = 567, 50 - 80 years) in a middle-sized Dutch town. Walking time was best predicted by attitude towards walking (partial correlation in model (partial r) 0.18;p r 0.12, p r 0.21 p r - 0.14, p r 0.28 p < 0.01). The model explained 20% of the total variance in walking time. Conclusion is that individual and social determinants predicted the most variance in walking time and that perceived environmental determinants played only a minor role. Health promotion actions may benefit from these insights.

Accessibility of urban regions on a low car diet-A research agenda for digital twins

1.Introduction Worldwide,cities and urbanised areas attract more people and economic activities.In addition,new ways of working,shopping and recreation,mobility and‘ownership’are introduced-all influenced by digitalisation.The United Nations(2018)expect the world-wide population living in urbanised regions to grow from 55% to 68% by 2050.However,concentration of residential,industrial,commercial,and recreational activities leads to an increasing pressure on land use and accessibility,potentially causing adverse environmental,health and liveability effects.Increasing housing density and decreasing space for transport infrastructure and parking call for new smart mobility approaches to ensure sustainable and inclusive accessibility.

Estimating Risk-aware Flexibility Areas for Electric Vehicle Charging Pools via AC Stochastic Optimal Power Flow

This paper introduces an AC stochastic optimal power flow(SOPF)for the flexibility management of electric vehicle(EV)charging pools in distribution networks under uncertainty.The AC SOPF considers discrete utility functions from charging pools as a compensation mechanism for eventual energy not served to their charging tasks.An application of the AC SOPF is described where a distribution system operator(DSO)requires flexibility to each charging pool in a day-ahead time frame,minimizing the cost for flexibility while guaranteeing technical limits.Flexibility areas are defined for each charging pool and calculated as a function of a risk parameter involving the uncertainty of the solution.Results show that all players can benefit from this approach,i.e.,the DSO obtains a riskaware solution,while charging pools/tasks perceive a reduction in the total energy payment due to flexibility services.

A Mixed-integer Linear Programming Model for Defining Customer Export Limit in PV-rich Low-voltage Distribution Networks

A photovoltaic(PV)-rich low-voltage(LV)distribution network poses a limit on the export power of PVs due to the voltage magnitude constraints.By defining a customer export limit,switching off the PV inverters can be avoided,and thus reducing power curtailment.Based on this,this paper proposes a mixed-integer nonlinear programming(MINLP)model to define such optimal customer export.The MINLP model aims to minimize the total PV power curtailment while considering the technical operation of the distribution network.First,a nonlinear mathematical formulation is presented.Then,a new set of linearizations approximating the Euclidean norm is introduced to turn the MINLP model into an MILP formulation that can be solved with reasonable computational effort.An extension to consider multiple stochastic scenarios is also presented.The proposed model has been tested in a real LV distribution network using smart meter measurements and irradiance profiles from a case study in the Netherlands.To assess the quality of the solution provided by the proposed MILP model,Monte Carlo simulations are executed in OpenDSS,while an error assessment between the original MINLP and the approximated MILP model has been conducted.

Simulation Architecture for Modelling Interaction Between User and Elbow-articulated Exoskeleton

The aim of our work is to improve the existing user-exoskeleton models by introducing a simulation architecture that can simulate its dynamic interaction, thereby altering the initial motion of the user. A simulation architecture is developed that uses the musculoskeletal models from OpenSim, and that implements an exoskeleton control algorithm and human response model in Matlab. The musculoskeletal models need to be extended with the response of a user to external forces to simulate the dy- namic interaction. A set of experiments was performed to fit this response model. A validation test showed that more than 80% of the variance of the motion could be explained. With the human response model in the combined simulation architecture, a simulation in which an object connects with the exoskeleton or with the human is performed. The effect of the exoskeleton on, among others, muscle excitation and altered motion can be assessed with this architecture. Our work can be used to better predict the effect an exoskeleton has on the user.

Reviewing the Chinese-Specific Reference Amounts Study Conducted by Sun et al.,2022

The need for region-specific food intake values to accurately estimate food allergen risk is underscored by the recent Ad Hoc Joint Food and Agriculture Organization/World Health Organization(FAO/WHO)Expert Consultation on Risk Assessment of Food Allergens(1).A recent study published by Sun et al.in China CDC Weekly 2022,titled A Chinese-Specific Reference Amounts Study with TNO Food Allergen Risk Assessment Models—China,2022,critically examines and applies a previously established sensitivity analysis aimed at deriving food intake values for food allergen risk assessment(RA)(2–3).In their examination of Chinese food consumption data,the authors find that“the 95th–99th percentiles of the food consumption distribution per eating occasion for condiments and chocolates are the optimal point estimates for use in deterministic allergen RA,aiming to protect 99%of allergic individuals from allergic reactions due to unintended peanut presence.”