Modelling of dust generation, transport and remobilization in full-metal fusion reactors

The design, licensing and operation of magnetic confinement fusion reactors impose various limitations on the amount of metallic dust particles residing inside the plasma chamber. In this context, predictive studies of dust production and migration constitute one of the main sources of relevant data. These are mainly conducted using dust transport codes, which rely on coupled dust-plasma and dust-wall interaction models, and require external input on the dust and droplet initial conditions. Some particularities of dust modelling in reactor-relevant conditions are analyzed with an emphasis on dust generation mechanisms relevant for disruption scenarios and on dust remobilization mechanisms relevant for ramp-up scenarios. Emerging topics such as dust production by runaway electron impact and pre-plasma remobilization of magnetic dust are also discussed.

Anti-gravity technology by non-positive equivalent mass revealing UFO flying secrets

In this paper, a novel kind of anti-gravity technology by non-positive equivalent mass of aircraft is presented to try to reveal UFO flying secrets. Starting with a two-degree-of-freedom system, it is found that the system could produce an infinite acceleration under the condition of zero dynamic equivalent mass[1], and also provide a movement opposite to the direction of the external force under the negative equivalent mass[2]. These two cases with non-positive equivalent mass[3] could both be regarded as a novel kind of anti-gravity technology[4,5], which is also verified by a designed dynamic simulation experiment. For any aircraft that can be regarded as a multi-degree-of-freedom system driven by engine or other external forces[6], the non-positive equivalent mass could be designed out once the external input including gravity and engine exciting forces is known[7]. Thus the anti-gravity technology for any aircraft could be realized, which could also be extended to matters related to flight, such as space ships, missiles, airplanes, etc[8].

Design of a Fully Integrated VHF CP-PLL Frequency Synthesizer with an All-Digital Defect-Oriented Built-In Self-Test.

This paper presents the design of an on-chip charge pump phase-locked loop (CP-PLL) with a fully digital defect oriented built-in self-test (BIST) for very-high frequency (VHF) applications. The frequency synthesizer has a 40 to 100 MHz tuning range and uses a ring voltage-controlled oscillator for frequency synthesis. The PLL exhibits a phase noise of -132 dBc/Hz at 1 MHz and consumes 1.8 mW on a 3 V supply. The BIST implementation uses fewer external input or output, is capable of efficient fault diagnosis, and is compact, posing a low area overhead. The integrated circuit design was realized in the AMI 0.6µ complementary metal oxide-semiconductor process.

Young and Aged Neuronal Tissue Dynamics With a Simplified Neuronal Patch Cellular Automata Model

Realistic single-cell neuronal dynamics are typically obtained by solving models that involve solving a set of differential equations similar to the Hodgkin-Huxley (HH) system. However, realistic simulations of neuronal tissue dynamics —especially at the organ level, the brain— can become intractable due to an explosion in the number of equations to be solved simultaneously. Consequently, such efforts of modeling tissue- or organ-level systems require a lot of computational time and the need for large computational resources. Here, we propose to utilize a cellular automata (CA) model as an efficient way of modeling a large number of neurons reducing both the computational time and memory requirement. First, a first-order approximation of the response function of each HH neuron is obtained and used as the response-curve automaton rule. We then considered a system where an external input is in a few cells. We utilize a Moore neighborhood (both totalistic and outer-totalistic rules) for the CA system used. The resulting steady-state dynamics of a two-dimensional (2D) neuronal patch of size 1, 024 × 1, 024 cells can be classified into three classes: (1) Class 0–inactive, (2) Class 1–spiking, and (3) Class 2–oscillatory. We also present results for different quasi-3D configurations starting from the 2D lattice and show that this classification is robust. The numerical modeling approach can find applications in the analysis of neuronal dynamics in mesoscopic scales in the brain (patch or regional). The method is applied to compare the dynamical properties of the young and aged population of neurons. The resulting dynamics of the aged population shows higher average steady-state activity 〈a(t → ∞)〉 than the younger population. The average steady-state activity 〈a(t → ∞)〉 is significantly simplified when the aged population is subjected to external input. The result conforms to the empirical data with aged neurons exhibiting higher firing rates as well as the presence of firing activity for aged neurons stimulated with lower external current.

Moving paradigms - conservation agriculture with alternative agronomics to minimize inputs.

The African Union Malabo Declaration outlines goals to achieve sustainable production practices for economic growth in the agriculture sector by 2025. Conservation Agriculture (CA) practices represent a climate smart and resource friendly sustainable production system, and these need to be adopted and refined. This will be a paradigm shift for academics, experts and farmers who are embedded in the intensive external-input monoculture tillage systems. From our review of literature, recent history has shown that CA systems are successful and profitable while using less external inputs and expending less energy. Energy use can be reduced by 40% and labour needs by 50%-90%. Research has shown that CA farming is superior in terms of enhancing soil functions, biodiversity, beneficial insects, energy consumption, greenhouse gas (GHG) emissions and resilience to extreme climate events. Nitrogen and other essential elemental crop needs can be reduced by 10%-70% through CA systems. African research and farm testing have shown integrated CA cropping systems can control insect and weed pests while providing more diverse economic crops. For the paradigm shift to occur quickly, efficiently and economically, institutions need to lead change. Policy makers need to start strategic changes to research and institutions by initiating support programmes identified by innovative researchers and agricultural leaders that can move the Malabo dial towards the 2025 goals.

Stochasticity invariance control in Pr1-xCaxMnO3 RRAM to enable large-scale stochastic recurrent neural networks

Emerging non-volatile memories have been proposed for a wide range of applications, from easing the von-Neumann bottleneck to neuromorphic applications. Specifically, scalable RRAMs based on Pr1-xCaxMnO3 (PCMO) exhibit analog switching have been demonstrated as an integrating neuron, an analog synapse, and a voltage-controlled oscillator. More recently, the inherent stochasticity of memristors has been proposed for efficient hardware implementations of Boltzmann Machines. However, as the problem size scales, the number of neurons increases and controlling the stochastic distribution tightly over many iterations is necessary. This requires parametric control over stochasticity. Here, we characterize the stochastic Set in PCMO RRAMs. We identify that the Set time distribution depends on the internal state of the device (i.e., resistance) in addition to external input (i.e., voltage pulse). This requires the confluence of contradictory properties like stochastic switching as well as deterministic state control in the same device. Unlike ‘stochastic-everywhere’ filamentary memristors, in PCMO RRAMs, we leverage the (i) stochastic Set in negative polarity and (ii) deterministic analog Reset in positive polarity to demonstrate 100× reduced Set time distribution drift. The impact on Boltzmann Machines’ performance is analyzed and as opposed to the “fixed external input stochasticity”, the “state-monitored stochasticity” can solve problems 20× larger in size. State monitoring also tunes out the device-to-device variability effect on distributions providing 10× better performance. In addition to the physical insights, this study establishes the use of experimental stochasticity in PCMO RRAMs in stochastic recurrent neural networks reliably over many iterations.

Sustainability Assessment of the Rare-Earth-Oxide Production Process and Comparison of Environmental Performance Improvements Based on Emergy Analysis

In recent years, the rapid development of the rare earth industry has had a serious impact on the environment. Some enterprises have taken measures to improve the production process. In order to explore the sustainability of this industry and these improvements’ environmental benefits, this paper combines emergy analysis and lifecycle assessment to evaluate and compare the production process of rare-earth oxides considering the three aspects of emergy flow, pollutant emissions, and emergy-based indicators. Changes in the emergy of pollutant emissions before and after improvement of the production process are discussed. The results show that the greatest inputs in the mining and beneficiation stage and smelting separation stage are labor force and service and non-renewable resources, respectively. These two production stages are highly dependent on external input and have weak competitiveness. Both stages place great pressure on the environment, so the bastnasite production process would be unsustainable in the long term. After the improvement, the environmental impact of the production process for bastnaesite changed significantly, indicating that the improvement effect of the wastewater treatment facilities and the change of fuel from coal to natural gas is remarkable.

Composition Analysis by STEM-EDX of Ternary Semiconductors by Internal References

A practical method to determine the composition within ternary heterostructured semiconductor compounds using energy-dispersive X-ray spectroscopy in scanning transmission electron microscopy is presented. The method requires minimal external input factors such as user-determined or calculated sensitivity factors by incorporating a known compositional relationship, here a fixed stoichiometric ratio in III–V compound semiconductors. The method is demonstrated for three different systems; AlGaAs/GaAs, GaAsSb/GaAs, and InGaN/GaN with three different specimen geometries and compared to conventional quantification approaches. The method incorporates absorption effects influencing the composition analysis without the need to know the thickness of the specimen. Large variations in absorption conditions and assumptions regarding the reference area limit the accuracy of the developed method.

Revisiting the Hillside: Organic, Aggregative Medium Density Housing in a Wellington Hillside Environment

<p>The ‘Conzen School’ of Urban Morphology identified by Kostof in his book The City Shaped, is a western way of looking at parcels of land, lots, and the street grid from above in a geometric manner imposed on the land, then analysing this in terms of land use pattern, town plan, and building form. This model of analysis and development lends itself to flat sites, and separated, isolated developments, and forms the basis for the existing model of development in western colonial nations. This thesis investigates whether an alternate development approach based on aggregative design can provide a viable alternative to the standard model of Medium Density Housing found in New Zealand. Investigation in the frame of Christopher Alexander’s New Theory of Urban Design, Lucien Kroll, and The New Urbanists addresses a new way of approaching these sites through the use of organic geometries and accumulative principals. Accompanying and informing this approach is a case study of vernacular Cycladic Architecture. In balance with the Cycladic case study the thesis addresses the acceptance of this model of development in a New Zealand context. In particular, with reference to the physical aspects of privacy, view, shared space as well as perceptions of ownership, individuality and identity in a higher density environment. The aggregative approach is similar to that explored through Ian Athfield’s Home in Khandallah; Athfield House. This housing and office complex is an early experiment into the same principles that this thesis addresses. The thesis develops a methodological approach to testing the aggregative nature of development and simulates this through the use of in studio design exercises. These exercises will be a combination of external input from other designers and internal; single author input. The final design outcome will be addressing the results of this simulation, the design principals, guidelines and rules, rather than producing a stand-alone design artifact.</p>