Modelling and simulation of a quad-rotor helicopter

Small size quad-rotor helicopters are often used due to the simplicity of their construction and maintenance, their ability to hover and also to take-off and land vertically. The first step in control development is an adequate dynamic system modelling, which should involve a faithful mathematical representation of the mechanical system. This paper presents a detailed dynamic analytical model of the quad-rotor helicopter using the linear Taylor series approximation method. The developed analytical model was simulated in the MatLab/Simulink environment and the dynamic behaviour of the quad-rotor assessed due to voltage changes. The model is further calibrated and linearized for use on any quad-rotor helicopter

Computational fluid dynamics model of a quad-rotor helicopter for dynamic analysis

The control and performance of a quad-rotor helicopter UAV is greatly influenced by its aerodynamics, which in turn is affected by the interactions with features in its remote environment. This paper presents details of Computational Fluid Dynamics (CFD) simulation and analysis of a quadrotor helicopter. It starts by presenting how SolidWorks software is used to develop a 3-D Computer Aided Design (CAD) model of the quad-rotor helicopter, then describes how CFD is used as a computer based mathematical modelling tool to simulate and analyze the effects of wind flow patterns on the performance and control of the quadrotor helicopter. For the purpose of developing a robust adaptive controller for the quad-rotor helicopter to withstand any environmental constraints, which is not within the scope of this paper; this work accurately models the quad-rotor static and dynamic characteristics from a limited number of time-accurate CFD simulations

The adoption and diffusion of pro-environmental stadium design

Research question: Owners and architects face mounting pressure to incorporate environmentally sustainable features in new arenas, ballparks, and stadiums. In this study, we apply Rogers’ diffusion-of-innovations framework to highlight the key influencers and factors contributing to the decision to adopt pro-environmental initiatives. Research method: We conducted interviews with 13 senior architects whose portfolios collectively contained over 25 eco-friendly sport facilities spanning Europe, Australia, Africa, and North America. The facilities discussed were used for a variety of leagues and events, including FIFA World Cup, the Olympic and Paralympic Games, college football and basketball, Major League Baseball (MLB), and the National Football League (NFL). The data were transcribed and analyzed following the open, axial, and selective coding sequence. Results and findings: The results of the study indicated that owners and quasi-owners reviewing green facility proposals considered the input of several groups, including the design firms, the media, political leaders, environmental activists, and local citizens. According to interviewees, the primary incentives for owners and quasi-owners to adopt sustainable designs were economic savings over the life of the facility, perception-management opportunities, and demonstration of their innovativeness. Finally, facility designers predicted the diffusion of pro-environmental sport facilities would continue in the immediate future. Implications: Innovation diffusion is driven by early adopters, who prioritize an innovation\u27s relative advantage and compatibility over its complexity, lack of trialability, and lack of observability. Additionally, pro-environmental facilities are being used by organizations to demonstrate both environmental stewardship and their cultures of innovation. Future research should explore both the decision-making process and barriers to sustainable design adoption in further depth

Solar Energy Harvesting for Wireless Sensor Network

Typically wireless sensor motes are operated by using small batteries because batteries are small in size and able to provide the sufficient energy for the motes. However batteries could not sustain the energy for the motes to operate for a long period. This is because the degradation of batteries could reduce the useable lifetime of the motes system. Besides that, batteries have limited energy capacity which could used up eventually. Aside from relying on the batteries to power up motes, one of the way to sustain the system is to harvest the sources of energy from the environment such as light, vibration, and thermal. These energies are renewable energy which does not cause pollution to the environment. In this project, solar energy harvesting have been proposed to sustain the energy requirement for the motes to operate. Experiments have been conducted to observe the solar panel charging characteristic to improve the efficiency and effectiveness of charging circuit to minimize the power loss. There are three main element in solar energy harvesting which are photovoltaic (PV) modules, solar charge controller and also energy storage. Based on the calculation, suitable PV modules, charging circuit and batteries are determined. Maximum Power Point Tracking (MPPT) technique are used for the charging circuit to maximize the efficiency conversion of the energy harvested from solar panel to charge the rechargeable lithium ion battery

STAYING CONNECTED IN A DISCONNECTED WORLD: SUPPORTING STUDENTS IN TRANSITION DURING COVID-19

In the current COVID-19 landscape, the shift to online partway through the semester for a large first-year biology unit was disorientating and isolating for many students. Learners were impacted by a myriad of factors including Zoom fatigue, access to quality internet, financial stress and mental health. Throughout the semester, we connected with students about how they felt they were tracking with their studies, support they needed to assist with their learning and their feedback on interventions implemented based on their responses from prior surveys. Consistency and flexibility with teaching approaches were key. Many students relied on keeping to their class timetables and live interaction with instructors to stay motivated, whilst others preferred to catch-up via recordings or online modules in their own time. We also organised regular Question & Answer sessions over Zoom to further facilitate live interactions between students and teachers. It was also challenging for the instructors to grow accustomed to teaching without relying on non-verbal communication cues from students. However, we came across pleasant discoveries from running online classes that we believe would also be useful approaches to implement in in-person classes to enhance engagement with learning in a large and diverse cohort

An objective approach to measuring video playback quality in lossy networks using TCP

In this work, we investigate a new objective measurement for assessing the video playback quality for services delivered in networks that use TCP as a transport layer protocol. We define the new metric as pause intensity to characterize the quality of playback in terms of its continuity since, in the case of TCP, data packets are protected from losses but not from delays. Using packet traces generated from real TCP connections in a lossy environment, we are able to simulate the playback of a video and monitor buffer behaviors in order to calculate pause intensity values. We also run subjective tests to verify the effectiveness of the metric introduced and show that the results of pause intensity and the subjective scores made over the same real video clips are closely correlated

CO Adsorption on the Surface of MgO from Periodic Coupled-Cluster Theory with Local Natural Orbitals: Adding to the Consensus

Accurate determination of the adsorption energy of CO on the MgO (001) surface has been a challenge for both computations and experiments over the past three decades. A recent computational study by Shi and co-workers (10.26434/chemrxiv-2023-h4czl) reported good agreement within $11$ meV ($1$ kJ/mol) between two popular theoretical methods: coupled-cluster with singles, doubles, and perturbative triples [CCSD(T)] and diffusion Monte Carlo. In this short note, we report results on the same problem from periodic Gaussian-based MP2, CCSD, and CCSD(T), with the latter two performed using a recently developed extension of the local natural orbital (LNO) approximation to problems with periodic boundary conditions. Our final periodic LNO-CCSD(T) adsorption energy ($-198 \pm 11$ meV) is in quantitative agreement with the embedded cluster-based LNO-CCSD(T) result ($-199 \pm 11$ meV) by Shi and co-workers. The computational cost of our periodic LNO-CCSD(T) calculations is comparable to that of the embedded cluster-based LNO-CCSD(T) and is 10 times less expensive than the plane-wave-based periodic canonical CCSD(T) or 50 times less expensive than the DMC calculations reported by Shi and co-workers. Our findings highlight the accuracy and computational efficiency of the periodic LNO-based approach for the simulation of surface chemistry with correlated wavefunction methods.Comment: 5 pages, 4 figures, 3 table

Ab initio surface chemistry with chemical accuracy

First-principles calculations are a cornerstone of modern surface science and heterogeneous catalysis. However, accurate reaction energies and barrier heights are frequently inaccessible due to the approximations demanded by the large number of atoms. Here we show that these approximations can be systematically eliminated to solve the many-electron Schr\"odinger equation for molecules on surfaces with chemical accuracy, commonly defined as 1 kcal/mol. As a demonstration, we study water on the surface of $\mathrm{Al}_2\mathrm{O}_3$ and $\mathrm{TiO}_2$, two prototypical and industrially important metal oxides for which we obtain converged energies at the level of coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)], commonly known as the "gold-standard" in molecular quantum chemistry. We definitively resolve the energetics associated with water adsorption and dissociation, enabling us to address recent experiments and to analyze the errors of more commonly used approximate theories.Comment: 6 pages (w/o SI), 3 figure