Standard Engineering Approach Research Articles

Conceptual Design and Multi-Disciplinary Computational Investigations of Multirotor Unmanned Aerial Vehicle for Environmental Applications

This study focuses on establishing a conceptual design for a multirotor unmanned aerial vehicle (UAV). The objectives of this octocopter are to reduce the number of flight cancelations and car accidents owing to low-visibility issues and to improve abnormal environmental conditions due to the presence of smoke. The proposed octocopter contains a convergent–divergent [CD] duct-based storage tank, which provides a platform to store saltwater and allows it to fly in foggy zones. Fine saltwater is sprayed from the octocopter and dispersed into the low clouds, thereby altering the vapor’s microphysical processes to break it up and improve visibility. The nature of the seawater and its enhanced fluid properties, due to the involvement of octocopter, creates the fluid flow mixing between atmospheric fluids and spraying particles, which increases the settling of foggy and smokey content groundward. For deployment, the conceptual design of the octocopter was initially constructed through analytical approaches. Additionally, three unique historical relationships were created. The standard engineering approaches involved in this work were stability analysis through MATLAB and fluid-property analysis through computational fluid dynamics (CFD) cum multiple reference frame (MRF) tools. The systematic model of this octocopter was developed by CATIA, and thereafter CFD and fluid–structure-interaction (FSI) analyses were computed, in ANSYS Workbench, on the octocopter for various environmental conditions. The aerodynamic forces on the drone, the enhancement of dynamic pressure by the presence of high amounts of rotors and nozzle sprayer, suitable material to resist aerodynamic loadings, and tests on the efficiency of the controller and its electronic components were investigated in detail. Finally, the proposed octocopter-based dynamic system was conceptually constructed.

Linking seasonal N2O emissions and nitrification failures to microbial dynamics in a SBR wastewater treatment plant

Nitrous oxide (N2O) is a strong greenhouse gas and causal for stratospheric ozone depletion. During biological nitrogen removal in wastewater treatment plants (WWTP), high N2O fluxes to the atmosphere can occur, typically exhibiting a seasonal emission pattern. Attempts to explain the peak emission phases in winter and spring using physico-chemical process data from WWTP were so far unsuccessful and new approaches are required. The complex and diverse microbial community of activated sludge used in biological treatment systems also exhibit substantial seasonal patterns. However, a potentially causal link between the seasonal patterns of microbial diversity and N2O emissions has not yet been investigated. Here we show that in a full-scale WWTP nitrification failure and N2O peak emissions, bad settleability of the activated sludge and a turbid effluent strongly correlate with a significant reduction in the microbial community diversity and shifts in community composition. During episodes of impaired performance, we observed a significant reduction in abundance for filamentous and nitrite oxidizing bacteria in all affected reactors. In some reactors that did not exhibit nitrification and settling failures, we observed a stable microbial community and no drastic loss of species. Standard engineering approaches to stabilize nitrification, such as increasing the aerobic sludge age and oxygen availability failed to improve the plant performance on this particular WWTP and replacing the activated sludge was the only measure applied by the operators to recover treatment performance in affected reactors. Our results demonstrate that disturbances of the sludge microbiome affect key structural and functional microbial groups, which lead to seasonal N2O emission patterns. To reduce N2O emissions from WWTP, it is therefore crucial to understand the drivers that lead to the microbial population dynamics in the activated sludge.

Railway cyber safety: An intelligent threat perspective

Cybersecurity threats to railways are increasing, both due to improvements in the techniques of hackers and the increasing merger of cyber and physical spheres. Accepted approaches to safety can be extended to consider the risks from cyber, however the nature of railways as complex cyber-physical systems of systems may require a broader approach beyond functional safety. This paper explores some of the cybersecurity hazards using a war gaming approach. The authors find that, while standard engineering approaches are effective in building new rail control system components, a broader and more creative consideration of attacks has benefits. In particular they identify the ability to cause mass disruption by targeting the fail-safes designed to ensure safety or auxiliary systems that are not directly classified within the scope of the ICS.

A Novel Framework for Modelling Wheelchairs under the Realm of Internet-of-Things

Innovations in research labs are driven to global markets by applied, established standard engineering practices, using state-of-the-art research that most likely results in manu-facturing highly effective and efficient engineered products. As a technology, that enables assistance to physically challenged people, wheelchairs have attracted researchers across the globe whilst showcasing an increased demand for higher production. However, wheelchairs in relation with the environments im-plementing Internet-of-things (IoT) devices, have been mostly overlooked to include the assessment of global market trends. Therefore, this paper proposes Acceptability Engineering (AE) framework to enhance the growth and expansion of markets relying on the environments, wherein wheelchairs can coordinate with IoT to enable smart technologies. AE as a standard engi-neering approach would help in – evaluating the characteristics of IoT-wheelchair environments, analysing their market trends, and highlighting the deficiencies between early and prevailing markets. This will significantly impact the manufacturers, who market wheelchairs specific to the IoT environments, and in addition manufacturers would be able to identify the potential users of their manufactured products.

Construction of information design theory

Designing, testing and manufacturing new technologies is a complex process that often requires many redesigns and rethinks. There are multiple criteria a new technological product must meet. Examples include the fact that it must provide a useful function, it must execute that function efficiently and effectively and it must be user friendly. In addition, cost of production and of sale are key considerations. Generally, once the manufacturer is satisfied with the results in all the criteria, the product can be released and sold. This iterative process whereby designs for manufacturing are gradually improved is the standard engineering approach. It is an extremely reliable way to ensure your product satisfies the basic criteria you set for it at the beginning. However, this is where the intellectual effort behind the design process stops. A product is made and, potentially, sells well and follow ups designed, but often little thought is put into unintended side effects of it. Dr Nariaki Nishino, who is an Associate Professor at the Department of Technology Management for Innovation, School of Engineering in The University of Tokyo, explains that new technology often receives little scrutiny of its unplanned effects. 'This is particularly true of modern technologies involving the digitisation of previously analogue products,' he outlines. Over the last 10 years, it has been generally seen as a positive and desirable to digitise as much as possible. Particularly, it has been seen as important to integrate digitised products extensively so that data from one is shared with another, etc. 'Such data sharing and integrated technology can provide many benefits for the user, however, there are side effects and important consequences to the sharing of so much personal data,' confirms Nishino. 'These unintended consequences are known as artefacts of the product and after ignored in the design process.' More broadly, such artefacts of engineering can include a wide range of the negatives of modern life – environmental problems, loneliness, urban decay. Nishino is a key team member of the Research into Artefacts, Centre for Engineering (RACE) division at The University of Tokyo, which was set up to examine how engineering could start considering these artefacts in the design process.

Wave Energy Converter Annual Energy Production Uncertainty Using Simulations

Critical to evaluating the economic viability of a wave energy project is: (1) a robust estimate of the electricity production throughout the project lifetime and (2) an understanding of the uncertainty associated with said estimate. Standardization efforts have established mean annual energy production (MAEP) as the metric for quantification of wave energy converter (WEC) electricity production and the performance matrix approach as the appropriate method for calculation. General acceptance of a method for calculating the MAEP uncertainty has not yet been achieved. Several authors have proposed methods based on the standard engineering approach to error propagation, however, a lack of available WEC deployment data has restricted testing of these methods. In this work the magnitude and sensitivity of MAEP uncertainty is investigated. The analysis is driven by data from simulated deployments of 2 WECs of different operating principle at 4 different locations. A Monte Carlo simulation approach is proposed for calculating the variability of MAEP estimates and is used to explore the sensitivity of the calculation. The uncertainty of MAEP ranged from 2%–20% of the mean value. Of the contributing uncertainties studied, the variability in the wave climate was found responsible for most of the uncertainty in MAEP. Uncertainty in MAEP differs considerably between WEC types and between deployment locations and is sensitive to the length of the input data-sets. This implies that if a certain maximum level of uncertainty in MAEP is targeted, the minimum required lengths of the input data-sets will be different for every WEC-location combination.

An approach to maintaining hydrological networks in the face of land use change

Ephemeral drainage patterns in the prairie pothole region of southern Alberta are not well understood at the landscape level. Municipal land use planning generally places very few constraints on development, which can leave the existing landscape topography and drainage patterns highly modified and engineered. Few if any features that exist within the pre-development landscape remain post-development. Part of the residential or industrial land development process is the creation of master drainage plans which focus on collecting and moving precipitation or snow melt away from roads and buildings through drainage ponds and piping systems. However, in prairie pothole landscapes, there is a landscape hydrology system that connects wetlands and sub-surface soil moisture flows and involves significant ephemeral components. These existing landscape flow systems provide ecosystem services in both flood and drought conditions. However, conventional land conversion processes do not generally recognize existing landscape processes like hydraulic connectivity in the development process. This creates a gap between the standard engineering approach and landscape structure and function which puts landscape processes and services at risk of being lost over time. The method demonstrated in this paper has been designed to bridge pre-development and post-development conditions for hydrologic flow systems. This method can be used as an additional cross-scalar information “layer” for use in the planning process to identify how utilities, roads and building sites can be spatially organized to complement rather than conflict with existing landscape flow systems in areas with minimal topographic relief and specifically in Prairie Pothole Region landscapes. This relatively simple technique can help reduce infrastructure costs and enables development to maintain natural flow systems and cross-scalar hydraulic connectivity.

Fracture toughness of locust cuticle

Insect cuticle is one of the most common biological materials, yet very little is known about its mechanical properties. Many parts of the insect exoskeleton, such as the jumping legs of locusts, have to withstand high and repeated loading without failure. This paper presents the first measurements of fracture toughness for insect cuticle using a standard engineering approach. Our results show that the fracture toughness of cuticle in locust hind legs is 4.12 MPa m(1/2) and decreases with desiccation of the cuticle. Stiffness and strength of the tibia cuticle were measured using buckling and cantilever bending and increased with desiccation. A combination of the cuticle's high toughness with a relatively low stiffness of 3.05 GPa results in a work of fracture of 5.56 kJ m(-2), which is amongst the highest of any biological material, giving the insect leg an exceptional ability to tolerate defects such as cracks and damage. Interestingly, insect cuticle achieves these unique properties without using reinforcement by a mineral phase, which is often found in other biological composite materials. These findings thus might inspire the development of new biomimetic composite materials.

Probabilistic Modeling of Floodwater Level for Dam Reservoirs

A probabilistic method of modeling the floodwater level in a dam reservoir is described the purpose of this paper is to add a probability dimension to hydraulic loading computations. Unlike the standard engineering approach, the method presented here incorporates two innovative aspects. First, the method uses a probabilistic hydrological method (simulated hydrographs for flood probability estimation method) based on simulation techniques, for generating multiple hydrological scenarios. Second, it can address the variability in reservoir level at the time of the occurrence of the flood event. The method generates a random set of floodwater levels from a random selection of flood hydrographs and headwater levels. Statistical analysis of the sample of reservoir levels obtained over a given period allows one to assess a probability distribution for floodwater levels. The method was tested on three applications representing dams having different operating rules and hydromorphological properties. The lessons learned with the present method as compared with the standard engineering approach are discussed from the viewpoint of inclusion in the modeling of the hydraulic loading on the dam and the assessment of the hydraulic safety of the dams.

Multiscale mesh generation on the sphere

A method for generating computational meshes for applications in ocean modeling is presented. The method uses a standard engineering approach for describing the geometry of the domain that requires meshing. The underlying sphere is parametrized using stereographic coordinates. Then, coastlines are described with cubic splines drawn in the stereographic parametric space. The mesh generation algorithm builds the mesh in the parametric plane using available techniques. The method enables to import coastlines from different data sets and, consequently, to build meshes of domains with highly variable length scales. The results include meshes together with numerical simulations of various kinds.

The third industrial fluid properties simulation challenge

The third industrial fluid properties simulation challenge was held from March to September 2006. As in the previous two events contestants were challenged to predict specific, industrially relevant, properties of fluid systems. Their efforts were judged based on the agreement of the predicted values with previously unpublished experimental data (provided by researchers at ExxonMobil and DuPont). The focus of this contest was on the transferability of modeling methods—the ability to predict properties for materials that are chemically different, or at different state points, to those used in model parameterization and validation. Nine groups attempted to compute bubble point pressures for mixtures of 1,1,1,2,3,3,3-heptafluoropropane (HFC-227ea) and ethanol at 343 K, given data for mixtures at 283 K, and given the pure component vapor pressures. They used a range of different techniques including statistical mechanical and molecular simulations-based approaches. Four of the groups were recognized for providing predictions that were significantly more accurate than would be obtained by extrapolation using the NRTL model (the standard engineering approach). Three groups undertook the more challenging “molecular transferability” problem, attempting to predict shear viscosities at two different state points for a range of diols and triols for which little experimental data was available.

Feedback Control Of Industrial Robots By Means Of Stochastic Optimization Techniques

AbstractThe standard engineering approach in control of industrial robots assumes all model parameters are known exactly and therefore can be modeled by their nominal values. Due to stochastic variations of the material, manufacturing errors, modeling errors and most important stochastic variations of the workspace environment (e.g. stochastic payload mass) this assumption does not hold. Hence, an approach that models these parameters by means of random variables was proposed, cf. [1]. Solving this substitute optimal control problem by means of direct optimal control discretization techniques allows the numerical computation of approximate optimal stochastic reference trajectories for the on‐line control process. These optimal reference trajectories are ‐ according to the chosen probability distribution ‐ valid for a variety of parameter configurations and are more stable toward parameter uncertainties. However, due to the stochastic parameters in the robots dynamic model, in the on‐line control process still deviations from the reference trajectories appear. Hence, a method for the construction of feedback controllers based on feedback linearization is presented.

FRACTURE IN COMPOSITES IN A NONLINEAR DYNAMIC SCHEME

We consider the fracture of a fibre reinforced graphite peek polymer when an axial periodical fatigue is applied. The energy-time diagram shows various critical points during the cyclic tensile loading. An analysis of the temporal series in the representative phase space, in terms of fractal and embedding dimension, enhances some properties not revealed by the standard engineering approach. In particular, variation of the correlation dimension before fracture may be used as a useful indicator for the subsequent breakdown.

Comparison of stormwater management in a karst terrane in Springfield, Missouri — case histories

Control of stormwater in sinkhole areas of Springfield, MO has involved the utilization of several standard approaches: concrete-lined channels draining into sinkholes; installation of drainage pipes into the sinkhole “eyes” (swallow holes); filling of sinkholes; elaborate drains or pumps to remove stormwater from one sinkhole and discharging into another drainage basin or sinkhole; and enlargement of swallow holes by excavation to increase drainage capacity. Past planning considerations and standard engineering approaches have resulted in flooding of sinkholes and drainage areas, including residential, industrial and commercial developments. Having recognized the inadequacy of existing designs to control flooding and the need to accommodate increased runoff from future development, the City of Springfield adopted an ordinance (effective 19 June 1989 and modified in 1990 and 1993) in response to public pressure and concerns over flooding in sinkholes and sinkhole drainage areas. Three sites were analyzed to examine the effectiveness of contrasting design approaches to stormwater management. These sites differ in vegetation, on-site/off-site considerations, and types of development proposed. All three sites are located within the East Cherry Street Sinkhole Area. The first site, a wooded tract with unmodified sinkholes was cleared and developed for residential use. Discharge of stormwater was directed into sinkholes, and erosion control consisted of hydro-mulching and sedimentation fences in sinkhole areas. East of this location are two parcels which differ in removal of vegetation and off-site drainage relationships. Stormwater design in these sites was adapted for modifications made to sinkholes during railroad and highway construction several decades earlier. Sediment fencing, hydro-mulching and detention berms augment infiltration, restrict erosion, retard discharge to sinkholes, and incorporate off-site considerations. Ongoing observations of stormwater behavior indicate problems of flooding and sediment control at the western site but minimal disruptions of existing drainage patterns at the eastern sites. Design calculation for the western site show adequate volume retention in sinkholes, but different design approaches were implemented to “soften” the impact of stormwater discharging into these sinkholes, allowing for minimal disruptions in the natural drainage network. The lack of recognition of sinkholes as integral parts of dynamic hydrologic systems may result in problems with on-site/off-site drainage. Standard engineering designs for stormwater detention are not appropriate for the hydraulic characteristics of the shallow karst drainage network. While runoff estimations are conservative, the design calculations fall short of adequately addressing actual stormwater runoff characteristics.

NMR signal reception: Virtual photons and coherent spontaneous emission

In portions of the magnetic resonance community, there is a misunderstanding of the process of nuclear magnetic resonance (NMR) signal generation and reception, and even in accepted texts, it is frequently described in terms of absorption and emission of radio waves, or radiation, by a two-level quantum system. While this explanation can be refuted, for those who do understand that the NMR free induction decay signal is easily explained by Faraday's law of induction, reconciling the presence of an induced electromotive force with an apparent absence of transitions between nuclear energy levels causes conceptual problems. This difficulty is examined, and an explanation of the signal given whereby Faraday's law is explained simply in terms of an exchange of virtual photons. The article thus attempts to reconcile the standard engineering approach to signal reception with a quantum mechanical description of the NMR phenomenon. Radiation damping and its relations to detection of the induced signal and to signal-to-noise ratio are then scrutinized, and the misleading nature of the appellation noted. In the process, it is shown that while damping is inherently necessary for signal detection and the transfer of energy that it entails, the degree of such damping depends on the efficiency of the detector—in other words, of the preamplifier in the NMR receiver—and can therefore be minimized. Mathematics in the article is kept to a minimum; proofs of the Principle of Reciprocity description of Faraday's law for reception of both signal and noise from a conducting sample are given in an appendix. ©1997 John Wiley & Sons, Inc. Concepts Magn Reson 9: 277–297, 1997

The Effect of Springing Response of a TLP on Tether Fatigue

Abstract The purpose of this paper is to investigate the effect on estimated fatigue damage of TLP tethers of the method used to model the springing response. In particular, the goal has been to look into the consequence for long-term fatigue calculation of modeling the springing response as a second-order, sum-frequency process as opposed to assuming that the springing response is Gaussian. It is shown that with a standard engineering approach to the calculation of long-term fatigue damage, this effect is in fact marginal. However, the deviation between the numerical estimates of the quadratic transfer function describing the springing response as provided by different computer codes is found to produce estimates of the long-term fatigue that exhibit substantial variability.