Expert Algorithmic and Imagistic Problem Solving Strategies in Advanced Chemistry

Abstract

Visualization and imagistic reasoning appear central to expert practice in science; however, expert use of these strategies on authentic tasks has not been examined in detail. This study documents how science experts use both algorithms and imagistic reasoning to solve problems. Using protocol analysis, we report expert chemists' preferential use of algorithms for solving spatial problems and imagistic reasoning for deducing spatial transformations. We observed experts employ algorithms to solve the majority of spatial tasks while reserving imagistic strategies to solve a class of tasks that required translating between representations. Strategy used varied widely among experts and tasks.     

Lunar-based enterprise infrastructure—hidden keys for long-term business success

Discussions on the creation of lunar bases or Moon-based industrial operations tend to focus on large issues i.e. transportation, cost, and/or sustainability. But assume that the fledging lunar enterprise is successful and engenders other Moon-based operations that also grow in terms of size and scope. Could success become more problematic than failure if some often minimized, yet essential, requirements for long-term human occupation of the Moon were ignored? This paper looks at lunar operations in terms of what will be required for long-term success as participants come to view themselves as terrestrial expatriates rather than engaged in short-term duty assignments.     

Ultracapacitors + DC-DC converters in regenerative braking system

An ultracapacitor system for an electric vehicle has been implemented. The device allows higher accelerations and decelerations of the vehicle with minimal loss of energy and minimal degradation of the main battery pack. The system uses a DC-DC power converter, which is connected between the ultracapacitor and the main battery pack. The design has been optimized in weight and size, by using water-cooled heat sinks for the power converter, and an aluminum coil with air core for the smoothing inductance. The ratings of the ultracapacitor are: nominal voltage: 300 Vdc; nominal current: 200 Adc; capacitance: 20 Farads. The amount of energy stored allows us to have 40 kW of power during 20 seconds, which is enough to accelerate the vehicle without the help of the traction batteries. The vehicle uses a brushless DC motor with a nominal power of 32 kW and a peak power of 53 kW. A control system based on a Digital Signal Processor (DSP) manipulates all the aforementioned variables and controls the Pulse Width Modulation (PWM) switching pattern of the converter transistors. The car used for the implementation of this system is a Chevrolet LUV truck.     

Sealed environment chamber for canopy light interception and trace hydrocarbon analyses.

Two sealed chambers were constructed, each measuring approximately 4.5 m x 3 m x 2.5 m (LxWxH). Heat exchangers and air handling components were integrated within the sealed environment. Construction materials were chosen to minimize off-gassing and oxidation. Acceptable materials included stainless steel, Teflon (TM), glass and Heresite (TM) or baked enamel coated metal parts. The glass-topped chambers have externally mounted microwave powered light sources providing minimum PAR at canopy level of 1000 micrometers m-2 s-1. Major gases (CO2, O2) were monitored. Other environmental variables relevant to plant production (humidity, temperature, nutrient solution) were monitored and controlled continuously. Typical environment control capability and system specifications are presented. The facility is described as a venue ideally suited to address specific research objectives in plant canopy light interception, such as the roles of novel microwave powered overhead and inner-canopy light sources for dense plant canopies. In addition, control of recycled hydroponic nutrient solutions and analysis of trace atmospheric hydrocarbons in the context of sealed environment life support can be concurrently monitored.     

What are the Best-Selling Jets in 2019 so Far?

正The General Aviation Manufacturers Association issued its Q2 2019 shipment report depicting mixed results for aircraft OEMs.Both the jet and piston markets continued the upward surge that began in 2018 but turboprops faltered.The latest GAMA Shipment Report represents a disappointment in the wake of two consecutive reports     

The Marginal Rao-Blackwellized Particle Filter for Mixed Linear/Nonlinear State Space Models

In this paper, the marginal Rao-Blackwellized particle filter （MRBPF）, which fuses the Rao-Blackwellized particle filter （RBPF） algorithm and the marginal particle filter （MPF） algorithm, is presented. The state space is divided into linear and non-linear parts, which can be estimated separately by the MPF and the optional Kalman filter. Through simulation in the terrain aided navigation （TAN） domain, it is demonstrated that, compared with the RBPF, the root mean square errors （RMSE） and the error variance of the nonlinear state estimations by the proposed MRBPF are respectively reduced by 29% and 96%, while the unique particle count is increased by 80%. It is also found that the MRBPF has better convergence properties, and analysis has shown that the existing RBPF is nothing more than a special case of the MRBPF.     

Single event upset investigations on the “Flying Laptop” satellite mission

The radiation effects in electronic parts are called single-event effects, which are deemed to be critical for space missions. This paper presents the Single Event Upsets that were observed in an onboard memory device of the Low Earth Orbit “Flying Laptop” satellite mission during its in-orbit operation. The Single Event Upsets were carefully mapped on the satellite orbital space itself and their root causes were investigated together with their rates of occurrence. Subsequently, the events were traced to show several root cause sources such as (i) trapped energetic protons leaking to low altitudes within the South Atlantic Anomaly, (ii) Solar Energetic Particles emitted by an impulsive event on 10 September 2017, and (iii) Galactic Cosmic Rays. A profound analysis was carried out on the observed flight data, and its corresponding results are actually in agreement with the standard energetic particle models. The presented results provide another important insight on the Single Event Upsets for future Low Earth Orbit satellite missions.     

Canadian advanced life support capacities and future directions

Canada began research on space-relevant biological life support systems in the early 1990s. Since that time Canadian capabilities have grown tremendously, placing Canada among the emerging leaders in biological life support systems. The rapid growth of Canadian expertise has been the result of several factors including a large and technically sophisticated greenhouse sector which successfully operates under challenging climatic conditions, well planned technology transfer strategies between the academic and industrial sectors, and a strong emphasis on international research collaborations. Recent activities such as Canada’s contribution of the Higher Plant Compartment of the European Space Agency’s MELiSSA Pilot Plant and the remote operation of the Arthur Clarke Mars Greenhouse in the Canadian High Arctic continue to demonstrate Canadian capabilities with direct applicability to advanced life support systems. There is also a significant latent potential within Canadian institutions and organizations with respect to directly applicable advanced life support technologies. These directly applicable research interests include such areas as horticultural management strategies (for candidate crops), growth media, food processing, water management, atmosphere management, energy management, waste management, imaging, environment sensors, thermal control, lighting systems, robotics, command and data handling, communications systems, structures, in-situ resource utilization, space analogues and mission operations. With this background and in collaboration with the Canadian aerospace industry sector, a roadmap for future life support contributions is presented here. This roadmap targets an objective of at least 50% food closure by 2050 (providing greater closure in oxygen, water recycling and carbon dioxide uptake). The Canadian advanced life support community has chosen to focus on lunar surface infrastructure and not low Earth orbit or transit systems (i.e. microgravity applications). To advance the technical readiness for the proposed lunar missions, including a lunar plant growth lander, lunar “salad machine” (i.e. small scale plant production unit) and a full scale lunar plant production system, a suite of terrestrial developments and analogue systems are proposed. As has been successfully demonstrated by past Canadian advanced life support activities, terrestrial technology transfer and the development of highly qualified personnel will serve as key outputs for Canadian advanced life support system research programs. This approach is designed to serve the Canadian greenhouse industry by developing compliance measures for mitigating environmental impact, reducing labour and energy costs as well as improving Canadian food security, safety and benefit northern/remote communities.     

Recent Progress in Physics-Based Models of the Plasmasphere

We describe recent progress in physics-based models of the plasmasphere using the fluid and the kinetic approaches. Global modeling of the dynamics and influence of the plasmasphere is presented. Results from global plasmasphere simulations are used to understand and quantify (i) the electric potential pattern and evolution during geomagnetic storms, and (ii) the influence of the plasmasphere on the excitation of electromagnetic ion cyclotron (EMIC) waves and precipitation of energetic ions in the inner magnetosphere. The interactions of the plasmasphere with the ionosphere and the other regions of the magnetosphere are pointed out. We show the results of simulations for the formation of the plasmapause and discuss the influence of plasmaspheric wind and of ultra low frequency (ULF) waves for transport of plasmaspheric material. Theoretical models used to describe the electric field and plasma distribution in the plasmasphere are presented. Model predictions are compared to recent Cluster and Image observations, but also to results of earlier models and satellite observations.     

Lessons Carved in Stone:Basics of Buddhism at Sichuan''''s Dazu Rock Carvings

Part I DAZU, SICHUAN PROVINCE "See the hungry devil? He eat the man!"the guide exclaimed, holding his charge in rapt attention atop Baoding Shan (Treasure Peak Mountain). He pointed to the Image of Six Ways of Transmigration,a carving of a towering demon that jutted from the cliff's face.