Carbon footprint: the (not so) hidden cost of high performance computing

Scientists, empowered by huge amounts of computing power, storage and memory are making world changing discoveries — including to help combat climate change. Loïc Lannelongue, a PhD student at the University of Cambridge, explores how high performance computing itself can lighten its carbon contribution.

Safe Operation Conditions of Electrical Power System Considering Power Balanceability Among Power Generators, Loads, and Storage Devices

The introduction of an energy storage system plays a vital role in the integration of renewable energy by keeping a stable operation and enhancing the flexibility of the power flow system, especially for an islanding microgrid which is not tied to a grid and for a self-contained microgrid which tries to stay independent from a grid as much as possible. To accommodate the effects of power fluctuations of distributed energy resources and power loads on power systems, a power flow assignment under power balance constraint is essential. However, due to power limitations of power devices, the capacity of storage devices, and power flow connections, the power balance may not be achieved. In this paper, we proposed a system characterization which describes the relation among power generators, power loads, power storage devices, and connections that must be satisfied for a system to operate by keeping SOC limitations of power storage devices. When we consider one power generator, one power load, and one power storage device connected at a single node, the generated energy by the generator minus the consumed energy by the load from some start time will increase/decrease the state of charge (SOC) for the storage device; hence, keeping SOC max/min limitations relies on whether the difference between the generated energy and the consumed energy stays within a certain range or not, which can be computed from the capacity Ess and other parameters. Our contribution in this paper is an extension and generalization of this observation to a system that consists of multiple fluctuating power generators, multiple fluctuating power loads, multiple storage devices, and connections that may not be a full connection between all devices. By carefully enumerating the connection-dependent flow paths of generated energy along the flow direction from generators to storages and loads, and enumerating the connection-dependent flow paths of consumed energy along the counter-flow direction from loads to storages and generators, we have formulated the increase/decrease of SOCs of storage devices caused by the imbalance between generated energy and consumed energy. Finally, considering the max/min limitations of SOCs and fluctuations of power generators and power loads, the conditions that the power generators and the power loads must have for SOCs of storage devices to maintain individual max/min limitations have been derived. The system characterization provides guidelines for a power flow system that can continue safe operation in the presence of power fluctuations. That is, in order for a system to have a feasible power flow assignment, there are the issues of how large the capacity of a power storage device should be, how large/small the maximum/minimum power/demand levels of the power generators and the power loads should be, and how the connection should be configured. Several examples using our system characterization are demonstrated to show the possible applications of our results.

Towards the Use of Flapping Wing Nano Aerial Vehicles

In the last decade, the potential of Micro Aerial Vehicles (MAVs) has generated an enormous interest in this technology and numerous applications have therefore been proposed in military and civilian fields. More recently, researchers have begun to work on a new and miniaturized generation called Flapping Wing Nano Aerial Vehicles (FWNAVs) who could be particularly promising for the indoor inspection. Before to be able to use efficiently these FWNAVs, there are however significant scientific and technical challenges to solve due to the scaling down. These include aerodynamics of low Reynolds number flow, small-scale power generation and power storage, navigation and communication, propulsion and control as well as manufacturability. This paper sets out the potential applications of such FWNAVs and reviews some of the challenges related to aerodynamics, stability, and design trends.

Experimental research of a re-equipment wheeled vehicle category M1 into electromobile

Today, there are more than 1 billion ICE equipped vehicles worldwide. Some of them are electric vehicles, hybrid vehicles of various types, hydrogen and gas power plants. The part of environmentally friendly wheeled vehicles is very small. With an increase in the price of oil products in the foreseeable future, all these cars with ICE will have to be either disposed of or refurbished. Moreover, mainly for other types of energy, more environmentally friendly, with the aim of further using the resource of the body and transmission, in order to provide them with the opportunity to develop their resource. One of the promising areas is the re-equipment of the power plant to an electric or hybrid one.Ensuring the required indicators of traction and speed properties of electric vehicles is a difficult task and requires a more detailed assessment due to the great difficulties in finding the initial data and internal parameters of the system. The presented article considers the vehicle ZAZ 965 "Zaporozhets" of category M1, which was re-equipment into a battery electromobile. The vehicle is equipped with a traction electric motor Balkankar DS 3.6/7.5/14, a power storage battery with lithium cells, a maximum voltage of 100.8 V and a capacity of 6.45 kW∙h. The traction motor control system is impulse with electronic power switches. Traction motor power is controlled by a controller that changes the pulse-width modulation (PWM) depending on the control signal from the control unit and the logic of the system. The change in PWM signal also occurs when the thermal protection is triggered, and in the event of a voltage drop on the power storage battery.Experimental road studies have been carried out, electricity consumption by a vehicle at various speeds has been determined, a coefficient has been determined that characterizes the ratio of consumed electrical energy to the kinetic energy of a vehicle. Comparison of the results of theoretical and experimental studies testifies to the adequacy of the developed mathematical model and the initial provisions underlying the calculation of the indicators of the efficiency of the use of electric energy by electromobile re-equipment from common vehi-cle with ICE.