Department Of Civil Research Articles

On the criteria for the initiation of motion in tidal inlets, deterministic and stochastic approaches

Details are given herein of the refinement and application of a three-dimensional layer integrated numerical model to predict morphological changes in tidal basins. The solution of governing differential equations, which consist of the conservation of mass and momentum for the hydrodynamics, the transport equation for the suspended sediment fluxes and the sediment mass conservation equation for the bed level changes are carried out by the use of Alternating Direction Implicit (ADI) Finite Difference Method (FDM). The model includes different criteria for the initiation of motion namely Shields (1936, Application of Similarity Principles and Turbulence Research to Bed load Movement, Hydrodynamics Laboratory, California Institute of Technology, Pub. No. 167), Kolahdoozan (1999, Numerical Modelling of Geomorphological Processes in Estuarine Waters, PhD Thesis, Department of Civil and Environmental Engineering, University of Bradford, Bradford, UK, 288) and Zanke (2003, On the Influence of Turbulence on the Initiation of Sediment Motion, International Journal of Sediment Research, 18(1), 17–31), to compare different aspects of flow conditions. As the flow is highly turbulent with the random nature of its components, many researchers have tried to express sediment transport processes by using stochastic approaches. In the current study both deterministic and stochastic methods are included in the numerical model to evaluate their accuracy and efficiency. To validate the numerical model results, laboratory measurements are used, with these being obtained from an earlier experimental program undertaken by the authors. Results of a short term bed level changes in a laboratory model harbor are included for the model verification purposes. Comparisons are undertaken using different criteria for the initiation of motion, with the results highlighting that the unsteadiness in the flow parameters included in the numerical model has a major effect on the bed level changes inside the harbor, in compare with the turbulence structure of the flow. The model is then applied to a real case study of the Humber Estuary, located in the UK, with comparisons being undertaken for different criteria for the initiation of motion, using both deterministic and stochastic approaches for the long term bed level predictions.

Model-based design and experimental validation of active vibration control for a stress ribbon bridge using pneumatic muscle actuators

This paper describes the development of an active vibration control system for a light and flexible stress ribbon footbridge. The 13 m span carbon fiber reinforced plastic (CFRP) stress ribbon bridge was built in the laboratory of the Department of Civil and Structural Engineering, Berlin Institute of Technology. Its lightness and flexibility result in high vibration sensitivity. To reduce pedestrian-induced vibrations, very light pneumatic muscle actuators are placed at handrail level, introducing control forces. First, a reduced discretized analytical model is derived for the stress ribbon bridge. To verify the analytical prediction, experiments without feedback control are conducted. Based on this model, a delayed velocity feedback control strategy is designed. To handle the nonlinearities of the muscle actuator, a subsidiary force control is implemented. Then the control performance from numerical simulation is verified by experiments under free vibration. As a result, analytical analyses agree well with experimental results. It is demonstrated that handrail-introduced forces can efficiently control the first mode response.

Reply to comment by Zhi-Hua Wang and Elie Bou-Zeid on “Impact of wave phase difference between soil surface heat flux and soil surface temperature on soil surface energy balance closure”

[1] We thank Wang and Bou-Zeid [2011] (hereinafter referred to as WB) for their comments about the phase difference between soil temperature and soil heat flux in our paper [Gao et al., 2010] (hereinafter referred to as GHL). In our previous work [Gao et al., 2008], we gave lots of derivations about the phase difference mentioned above. The main difference between WB's comments and our work (GHL) is the third term of their equation (11), which denotes the transient disturbance caused by starting the oscillation of surface temperature from the initial condition. In micrometeorological experimental research, this term is usually neglected because it is small. For soil surface heat flux, the transient term vanishes. [2] Our assurance (see GHL) that all of Rn, H and LE have phases identical to that of soil surface temperature may be more complicated for vegetation (such as dense grassland) surfaces because there are complicated physiological and physical processes [e.g., Sellers et al., 1996a, 1996b]. In the database used by WB, the sensible heat flux and latent heat fluxes partly come from grass canopy and partly come from ground soil surface, and the proportion depends on leaf area index, vegetation type and canopy height, etc. From the Web site WB provided, we failed to find how to decide the soil heat flux G0 which WB used in their comments. For grassland surface energy analysis, we should account for the heat storages in both grass and soil into soil surface heat flux. The same principle applies to soil surface temperature, and it should represent the canopy temperature and ground soil surface temperature [e.g., Sellers et al., 1996a, 1996b]. We suggest WB provide more information around soil surface heat flux and soil surface temperature determinations in their comments for further discussion. We found that WB's data of LE and H varied quite a lot (big changes from time to time, particularly around 1000, 1100, and 1200 EST) in their Figure 1b. Since Rn is quite smooth, G0 should have varied from time to time based on G0 = Rn-H-LE. The net radiation (Rn) shown in WB's Figure 1b was derived from four components of radiation budget: incoming and outgoing components of short- and long-wave radiation. I suggest WB insert a figure to show the diurnal variation courses of these four components to see whether the surface temperature measured by a thermal infrared radiometer has a phase identical to the outgoing long-wave radiation. Furthermore, there are three essential issues WB should address for their Figure 1b. (1) Rn suddenly decreased for a while at 1315 and 1415 (EST), and it was most probably caused by the intermittent cloudiness. However, both H and LE courses have a nick around 1200 (EST). As is well known, both H and LE should respond to change in Rn accordingly. (2) Both H and LE reached their peaks of 120 W m−2 and 160 W m−2, respectively, around 1115 (EST) when Rn and G0 were 260 W m−2 and 20 W m−2, respectively. It is obvious that Rn < H+LE under the condition that G0 > 0. This result may be caused by the different footprints of Rn, H and LE. (3) WB computed the eddy covariance fluxes over 5 min periods. Why select 5 min rather than 20 min or 30 min for average as is usual? [3] This study was supported by the National Program on Key Basic Research Project of China (973) under grant 2010CB428502, by National Natural Science Foundation of China under grants 40975009 and 40906023, by China Meteorological Administration under grant GYHY201006024, and by the Centurial Program sponsored by the Chinese Academy of Sciences. I am grateful to Heping Liu (from Department of Civil and Environmental Engineering, Washington State University) for his valuable comments.

Toxic Chemicals in Toys and Children’s Products

ADVERTISEMENT RETURN TO ISSUELetterNEXTToxic Chemicals in Toys and Children’s ProductsMert Guney and Gerald J. Zagury*View Author Information Department of Civil, Geological and Mining Engineering, École Polytechnique de Montréal, Montreal, QC, Canada*E-mail: [email protected]; telephone: 1 (514) 340-4711, ext. 4980.Cite this: Environ. Sci. Technol. 2011, 45, 9, 3819Publication Date (Web):March 23, 2011Publication History Published online23 March 2011Published inissue 1 May 2011https://doi.org/10.1021/es200810sCopyright © 2011 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1668Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (633 KB) Get e-AlertsSUBJECTS:Environmental pollution,Impurities,Metals,Organic compounds,Risk assessment Get e-Alerts

Influence of Dissolved Organic Matter on the Environmental Fate of Metals, Nanoparticles, and Colloids

ADVERTISEMENT RETURN TO ISSUEPREVFeatureNEXTInfluence of Dissolved Organic Matter on the Environmental Fate of Metals, Nanoparticles, and ColloidsGeorge R. Aiken*‡, Heileen Hsu-Kim§, and Joseph N. Ryan⊥View Author Information‡ U.S. Geological Survey, 3215 Marine Street, Boulder, Colorado 80303, United States§ Department of Civil and Environmental Engineering, Duke University, Box 90287, Durham, North Carolina 27708, United States⊥ Department of Civil, Environmental, and Architectural Engineering, University of Colorado, Boulder, Colorado 80309, United States *E-mail: [email protected]Cite this: Environ. Sci. Technol. 2011, 45, 8, 3196–3201Publication Date (Web):March 15, 2011Publication History Published online15 March 2011Published inissue 15 April 2011https://doi.org/10.1021/es103992sCopyright © 2011 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views16408Altmetric-Citations558LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (4 MB) Get e-AlertsSUBJECTS:Colloids,Dissolved organic matter,Metal oxide nanoparticles,Metals,Nanoparticles Get e-Alerts

A Way Forward: Assessing the Demonstrated Leadership of Graduate Civil Engineering and Construction Management Students

The year 2007 was a year for visionary change in the field of civil engineering in the United States. This vision did not go unnoticed in the Caribbean. At the Department of Civil and Environmental Engineering of the University of the West Indies, the M.Sc. programs have been restructured to meet the U.K. Joint Board of Moderators requirements for academic accreditation and to fulfill the mandate of the vice chancellor to develop 12 desired attributes, with leadership being among them. A model was developed in a course, Practical Team Project, to measure the learning outcome of leadership by combining the Project Management Institute body of knowledge areas and the Institute of Civil Engineers (ICE) development objectives. The course prepares students for professional review at the Incorporated Engineering (I.Eng.) level with the ICE and gives them similar standing in other Washington Accord signatory countries. This new initiative for the university required innovative assessment techniques, such as 360-degree feedback and zero tolerance, to evaluate the demonstrated leadership of the graduate students. Analytical tools such as ANOVA and t-test were used to justify the effectiveness of the chosen model.

Calibration of the soil loss measurement method at the Masse experimental station

Abstract The paper introduces the results of the calibration of the runoff and sediment concentration measurement system adopted at the Masse experimental station recently set up by the Department of Civil and Environmental Engineering to study erosion processes at the plot scale in Central Italy. The collected runoff is stored in cubic tanks equipped with ten taps for sampling the suspension. When an erosive event occurs, the plot runoff volume is measured by means of the water level in the tank, and the corresponding mean measured concentration in the suspension is quantified. The calibration curve of the specific storage system and of the measurement procedure used makes it possible to derive the actual concentration. The event plot soil loss is quantified as the product of the actual concentration and the runoff volume. The calibration curve was determined for two soil types. In any case a linear relationship was found between an actual and measured concentration. Slopes of regression vary with water depths in the tank. The calibration model does not significantly vary with the soil type considered due to the low difference in the coarse sand percentage in the two soils (according to Stokes' law). The measurement devices and the sampling procedure being equal, the calibration curve determined can be used to correct the measured concentration in the actual concentration for any soils that are characterized by a coarse sand percentage similar to that of the soil used to derive it.

Evaluation of satellite-retrieved extreme precipitation rates across the central United States

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, D02115, doi:10.1029/2010JD014741, 2011 Evaluation of satellite‐retrieved extreme precipitation rates across the central United States A. AghaKouchak, 1 A. Behrangi, 2 S. Sorooshian, 1 K. Hsu, 1 and E. Amitai 3,4 Received 10 July 2010; revised 10 September 2010; accepted 27 October 2010; published 26 January 2011. [ 1 ] Water resources management, forecasting, and decision making require reliable estimates of precipitation. Extreme precipitation events are of particular importance because of their severe impact on the economy, the environment, and the society. In recent years, the emergence of various satellite‐retrieved precipitation products with high spatial resolutions and global coverage have resulted in new sources of uninterrupted precipitation estimates. However, satellite‐based estimates are not well integrated into operational and decision‐making applications because of a lack of information regarding the associated uncertainties and reliability of these products. In this study, four satellite‐ derived precipitation products (CMORPH, PERSIANN, TMPA‐RT, and TMPA‐V6) are evaluated with respect to their performance in capturing precipitation extremes. The Stage IV (radar‐based, gauge‐adjusted) precipitation estimates are used as reference data. The results show that with respect to the probability of detecting extremes and the volume of correctly identified precipitation, CMORPH and PERSIANN data sets lead to better estimates. However, their false alarm ratio and volume are higher than those of TMPA‐RT and TMPA‐V6. Overall, no single precipitation product can be considered ideal for detecting extreme events. In fact, all precipitation products tend to miss a significant volume of rainfall. With respect to verification metrics used in this study, the performance of all satellite products tended to worsen as the choice of extreme precipitation threshold increased. The analyses suggest that extensive efforts are necessary to develop algorithms that can capture extremes more reliably. Citation: AghaKouchak, A., A. Behrangi, S. Sorooshian, K. Hsu, and E. Amitai (2011), Evaluation of satellite‐retrieved extreme precipitation rates across the central United States, J. Geophys. Res., 116, D02115, doi:10.1029/2010JD014741. 1. Introduction [ 2 ] Precipitation plays a significant role in weather research, monitoring, and predictions. Improving our understanding of weather and climate, along with the development of reliable and uninterrupted measurements, are essential for proper assessment of weather conditions. Currently, in situ and radar‐based precipitation data are the major input for streamflow forecasts, flash flood warnings, and weather watches across the United States. While some regions have long‐term historical in situ precipitation measurements, poor spatial sampling makes the data inadequate to support monitoring, detection, and forecast studies. On the other hand, in most parts of the globe (except in a few developed countries), radar installations for precipitation measurements Department of Civil and Environmental Engineering, University of California, Irvine, California, USA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA. NASA Goddard Space Flight Center, Greenbelt, Maryland, USA. School of Earth and Environmental Sciences, Chapman University, Orange, California, USA. Copyright 2011 by the American Geophysical Union. 0148‐0227/11/2010JD014741 are not available. In the United States, with one of the most sophisticated radar measurement networks in the world, regions with extensive topographic relief (e.g., the western and southwestern United States) suffer from poor or non- existent radar coverage [Maddox et al., 2002]. In fact, Maddox et al. [2002] showed that at lower levels (e.g., 1000 m above ground level), which are closer estimates to ground‐level precipitation, the radar coverage area is sub- stantially smaller than at higher levels (e.g., 3000 m above ground level). [ 3 ] Clearly, the lack or absence of ground‐based precipi- tation networks hampers the development and use of flood and drought warning models, hydrological models, and extreme weather monitoring and decision‐making systems. Therefore, there exists the need to achieve alternative esti- mates of precipitation with sufficient sampling density, reliability, and accuracy to enable utilization of data for operational applications. Satellite‐derived precipitation esti- mates have the potential to improve precipitation observation at a global scale. In recent years, the National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA), and many other inter- national sponsored satellite missions have led to an increase in available precipitation data. These remotely sensed data have several advantages over in situ measurements, including D02115 1 of 11

An Evaluation of Programme Educational Objectives and Programme Outcomes for Civil Engineering Programmes

The Department of Civil & Structural Engineering at the Universiti Kebangsaan Malaysia (UKM) offers two Civil Engineering undergraduate programmes. This study is to evaluate the achievement of Programme Educational Objectives (PEOs) by indirect assessment consists of parents, alumni and employer surveys, while the Programme Outcomes (POs) is done by surveys on graduating students, industrial training employers, alumni and industry employers. The scores used for the surveys are on a scale of 1 to 5. Generally, the results for PEOs and POs from the surveys indicated most of the ratings are between 3 and 5. This is an indication that the PEOs specified for the programme are achieved.

The Program Outcomes Achievement for Basic Reinforced Concrete Design Course between Two Different Sessions

This study aims to assess the students’ achievement of program outcomes (POs) for the Reinforced Concrete Design Course. The POs achievement for students in session 2009/2010 is evaluated and then compared with the previous session of 2008/2009. The course was selected as it is a compulsory course for all students in the Department of Civil and Structural Engineering (JKAS) and furthermore the project given to the students are always related to the real structural design project. POs achievement for the session 2009/2010 was evaluated based on the new improved POs compared to the previous POs used in session 2008/2009. The assessment of POs achievement is measured based on final examination, mid semester examination, tutorials and group project. The comparison results between the two sessions have successfully showed the increment of students’ achievement around 9-39% on all identified POs. The comparison is made in view to look on how effective the continuous quality improvement (CQI) that has been proposed in the previous session can affect the students’ performance. The effect of changes in the new improved PO as outlined in the course will also be assessed and discussed.

INDOOR AIR QUALITY: Scented Products Emit a Bouquet of VOCs

A survey of selected scented consumer goods showed the products emitted more than 100 volatile organic compounds (VOCs), including some that are classified as toxic or hazardous by federal laws.1 Even products advertised as “green,” “natural,” or “organic” emitted as many hazardous chemicals as standard ones. Anne Steinemann, a professor of civil and environmental engineering and public affairs at the University of Washington, Seattle, and colleagues used gas chromatography–mass spectrometry to analyze VOCs given off by the products. They tested 25 air fresheners, laundry detergents, fabric softeners, dryer sheets, disinfectants, dish detergents, all-purpose cleaners, soaps, hand sanitizers, lotions, deodorants, and shampoos. Many of the products tested are top sellers in their category. A single fragrance in a product can contain a mixture of hundreds of chemicals, some of which (e.g., limonene, a citrus scent) react with ozone in ambient air to form dangerous secondary pollutants, including formaldehyde.2 The researchers detected 133 different VOCs. Most commonly detected were limonene, α- and β-pinene (pine scents), and ethanol and acetone (often used as carriers for fragrance chemicals).1 Steinemann and colleagues found the average number of VOCs emitted was 17.1 Each product emitted 1–8 toxic or hazardous chemicals, and close to half (44%) generated at least 1 of 24 carcinogenic hazardous air pollutants, such as acetaldehyde, 1,4-dioxane, formaldehyde, or methylene chloride.1 These hazardous air pollutants have no safe exposure level, according to the U.S. Environmental Protection Agency.3 Of the 133 VOCs detected, only ethanol was listed on any label (for 2 products), and only ethanol and 2-butoxyethanol were listed on any Material Safety Data Sheet (for 5 products and 1 product, respectively).1 The Consumer Product Safety Commission, which regulates cleaning supplies, air fresheners, and laundry products, currently does not require manufacturers to disclose any ingredients on the label, including fragrances in these products.4 The same is true for fragrances in personal care items, which are overseen by the Food and Drug Administration.5 The Household Product Labeling Act, currently under review in the U.S. Senate, would require manufacturers to label consumer products with all ingredients, including fragrance mixtures.6 “Disclosing all ingredients could be a first step to understanding potential toxicity and health effects,” says Steinemann. Although the authors did not seek to assess whether use of any of the products studied would be associated with any risk,1 Steinemann says she receives hundreds of letters, phone calls, and e-mails from people who report a variety of respiratory, dermatological, and neurological problems they attribute to scented products: “Children have seizures after exposure to dryer sheets, and adults pass out around air fresheners,” she says.7 Steinemann and colleague Stanley M. Caress have written elsewhere that 19% of respondents across two U.S. telephone surveys reported health problems they attributed to air fresheners, and nearly 11% reported irritation they attributed to scented laundry products vented outdoors.8 “It’s important to take people’s complaints seriously,” says Steinemann, because “these human experiences are helping to inform science.” One of her next projects will focus on biomarkers of exposure and effect to better understand how fragranced products may cause a range of adverse health effects. “The ultimate goal is to improve public health,” Steinemann says. For now, she recommends cleaning with basic supplies like vinegar and baking soda. Steinemann’s study “strongly suggests that we need to find unscented alternatives for cleaning our homes, laundry, and ourselves,” says Claudia Miller, an allergist and immunologist at the University of Texas Health Science Center at San Antonio. An expert in chemical sensitivity, or toxicant-induced loss of tolerance, Miller created the Quick Environmental Exposure and Sensitivity Inventory,9 a screening tool for chemical intolerance. According to Miller, products intended to keep homes smelling fresh can set people up for a lifetime of chemically induced illness, and repeated exposure to small amounts of household chemicals can trigger symptoms to previously tolerated chemicals.10 “The best smell is no smell,” Miller says.

Active vibration control of a light and flexible stress ribbon footbridge using pneumatic muscles

AbstractThis paper describes the development of an active vibration control system for a light and flexible stress ribbon footbridge. The 13 m span Carbon Fiber Reinforced Plastics (CFRP) stress ribbon bridge was built in the laboratory of the Department of Civil and Structural Engineering, Berlin Institute of Technology. Its lightness and flexibility result in high vibration sensitivity. To reduce pedestrian-induced vibrations, very light pneumatic muscle actuators are placed at handrail level introducing control forces. First, a reduced discretized analytical model is derived for the stress ribbon bridge. To verify the analytical prediction, experiments without feedback control are conducted. Based on this model, a velocity feedback control strategy is designed to actively control first mode vibrations. To handle the nonlinearities of the muscle actuator a subsidiary nonlinear force controller is implemented based on exact linearisation methods. The stability of the entire closed-loop system with actuator saturation is investigated by the Popov Criterion. Control performance is verified by experiments. It is demonstrated that handrail introduced forces can efficiently control the first mode response.

A Study of Students’ Information Searching Strategies

Concerns have been expressed with respect to students’ ability to search for information using electronic search engines and databases. This research adopted a structured method comprising a combination of questionnaire surveys, an observational study and a ‘sense making’ interview to assess the information searching skills of a group of 14 students undertaking their final year dissertation studies on undergraduate programmes within the Department of Civil and Building Engineering at Loughborough University. The findings reveal that the participants encountered problems with each type of search engine used (Google, Metalib, the Library OPAC system, and individual databases) and lacked knowledge of how to use advanced search strategies. All the participants formulated queries using simple words or free text and there was no evidence of consideration of structured word searching using systematically selected keywords. The results indicate priority areas for additional tuition in information literacy.

Are stochastic point rainfall models able to preserve extreme flood statistics?

Hydrological ProcessesVolume 24, Issue 23 p. 3439-3445 Invited Commentary Are stochastic point rainfall models able to preserve extreme flood statistics? Niko E. C. Verhoest, Corresponding Author Niko E. C. Verhoest niko.verhoest@ugent.be Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, BelgiumLaboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.===Search for more papers by this authorS. Vandenberghe, S. Vandenberghe Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, BelgiumSearch for more papers by this authorP. Cabus, P. Cabus VMM (Flemish Environmental Agency), Sluizenweg 2, B-9050 Gentbrugge, BelgiumSearch for more papers by this authorC. Onof, C. Onof Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, London SW72AZ, UKSearch for more papers by this authorT. Meca-Figueras, T. Meca-Figueras Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, London SW72AZ, UKSearch for more papers by this authorS. Jameleddine, S. Jameleddine Ecole des Ponts Paris Tech, 6-8 Avenue Blaise-Pascal, Cité Descartes, 77455 Champs-sur-Marne, Marne-la-Vallée Cedex 2, FranceSearch for more papers by this author Niko E. C. Verhoest, Corresponding Author Niko E. C. Verhoest niko.verhoest@ugent.be Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, BelgiumLaboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, Belgium.===Search for more papers by this authorS. Vandenberghe, S. Vandenberghe Laboratory of Hydrology and Water Management, Ghent University, Coupure links 653, B-9000 Ghent, BelgiumSearch for more papers by this authorP. Cabus, P. Cabus VMM (Flemish Environmental Agency), Sluizenweg 2, B-9050 Gentbrugge, BelgiumSearch for more papers by this authorC. Onof, C. Onof Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, London SW72AZ, UKSearch for more papers by this authorT. Meca-Figueras, T. Meca-Figueras Department of Civil and Environmental Engineering, Imperial College London, Skempton Building, London SW72AZ, UKSearch for more papers by this authorS. Jameleddine, S. Jameleddine Ecole des Ponts Paris Tech, 6-8 Avenue Blaise-Pascal, Cité Descartes, 77455 Champs-sur-Marne, Marne-la-Vallée Cedex 2, FranceSearch for more papers by this author First published: 07 October 2010 https://doi.org/10.1002/hyp.7867Citations: 54Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume24, Issue2315 November 2010Pages 3439-3445 RelatedInformation

Applying Physics to an Undergraduate Design for an Unmanned Aerial System

The Department of Civil and Mechanical Engineering at the United States Military Academy requires its graduates to complete an integrative capstone design in their senior year. One of these projects involves the design, construction, testing, and demonstration of a small, highly autonomous, unmanned aerial system (UAS). This particular capstone option was added to the list of available capstone projects in the fall of 2005. In the past, while students have been able to complete the design process relatively well, an area of deficiency for all capstone design teams has been the physical modeling of their design before construction. This paper describes the progression of physical modeling and analysis for the systems' air vehicles over the course of the three years of the project's existence. In the first year, the two teams did little or no modeling. During the second year of the project, with three different teams, some modeling was attempted, but not verified through testing once the designs were constructed. At the start of the third year, one of the faculty advisors developed a detailed procedure for aerodynamic modeling and performance analysis, called the ‘Alpha .60 Laboratory’. To augment the previous year's design pedagogy with an inductive learning component, the students were required to complete the laboratory on an existing airframe. They were then required to apply the same analysis to each alternative developed through the engineering design process. Upon selection and construction of their final design, the students were required to validate their analytical predictions through flight testing. Preliminary results have shown marked improvement in the detail of the analysis and the level of the students' understanding of the underlying physics. An assessment of the laboratory's impact on the following year's designs is also presented.

A threshold-based earthquake early warning using dense accelerometer networks

Most earthquake early warning systems (EEWS) developed so far are conceived as either ‘regional’ (network-based) or ‘on-site’ (stand-alone) systems. The recent implementation of nationwide, high dynamic range, dense accelerometer arrays makes now available, potentially in real time, unsaturated waveforms of moderate-to-large magnitude earthquakes recorded at very short epicentral distances (<10–20 km). This would allow for a drastic increase of the early warning lead-time, for example, the time between the alert notification and the arrival time of potentially destructive waves at a given target site. By analysing strong motion data from modern accelerograph networks in Japan, Taiwan and Italy, we propose an integrated regional/on-site early warning method, which can be used in the very first seconds after a moderate-to-large earthquake to map the most probable damaged zones. The method is based on the real-time measurement of the period (τ_c) and peak displacement (Pd) parameters at stations located at increasing distances from the earthquake epicentre. The recorded values of early warning parameters are compared to threshold values, which are set for a minimum magnitude 6 and instrumental intensity VII, according to the empirical regression analyses of strong motion data. At each recording site the alert level is assigned based on a decisional table with four alert levels defined upon critical values of the parameters Pd and τ_c, which are set according to the error bounds estimated on the derived prediction equations. Given a real time, evolutionary estimation of earthquake location from first P arrivals, the method furnishes an estimation of the extent of potential damage zone as inferred from continuously updated averages of the period parameter and from mapping of the alert levels determined at the near-source accelerometer stations. The off-line application of the method to strong motion records of the M_w 6.3, 2009 Central Italy earthquake shows a very consistent match between the rapidly predicted (within a few seconds from the first recorded P wave) and observed damage zone, the latter being mapped from detailed macroseismic surveys a few days after the event. The proposed approach is suitable for Italy, where, during the last two decades, a dense network of wide dynamic-range accelerometer arrays has been deployed by the Department of Civil Protection (DPC), the Istituto Nazionale di Geofisica e Vulcanologia (INGV) and other regional research agencies.

New evidence of the outer Dinaric deformation front in the Grado area (NE-Italy)

A well Grado-1 was drilled down to 1,108 m reaching Mesozoic shelf carbonates which occur in the structural highs in the Lignano–Grado area. The well was completed with geophysical logs in the open-hole interval from −700 to −1,108 m. The drilling bit met the nummulitic shelf Palaeogene limestone at −616.5 m and Mesozoic (Upper Cretaceous) platform around −1,007 m. About 400 m thick Palaeogene interval appears affected by open fractures which we consider linked up to a reverse fault and a tectonic duplex of the Palaeogene limestone interval is hypothesized. The feature corresponds to the outer deformation front of the Dinaric thrusts system and looks still active. Palaeogene limestone sequence is analogous to the outcrops in the northern Istria and the stratigraphy in the oil wells offshore northern Dalmatia. The drilling target was the characterization of the nature of geothermal resources in the Friuli lower plain and lagoons region, following the long-term investigations of the Department of Civil and Environmental Engineering of the Trieste University. The geothermal resource was found in correspondence of the above mentioned open fracture zone and below it, with salty hot waters at a temperature of 42°C, increasing with depth, and a flow of 25 l/s arriving to the surface with 2.8 pressure bars.

Methods to Derive the Differential Equation of the Free Surface Boundary

GroundwaterVolume 48, Issue 4 p. 486-493 Methods to Derive the Differential Equation of the Free Surface Boundary Jacob Bear, Jacob Bear Department of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel. School of Engineering, Kinneret College on Sea of Galilee, Zemach, Israel; cvrbear@tx.technion.ac.ilSearch for more papers by this authorAlexander H.-D. Cheng, Corresponding Author Alexander H.-D. Cheng Department of Civil Engineering, University of Mississippi, MS 38677; acheng@olemiss.eduSearch for more papers by this authorVedat Batu, Vedat Batu URS Corporation, 100 South Wacker Drive, Chicago, IL 60606; vedat_batu@urscorpSearch for more papers by this authorChongxi Chen, Chongxi Chen Institute of Environmental Geology, China University of Geosciences, Wuhan, 430074, China.Search for more papers by this authorXingxing Kuang, Xingxing Kuang Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; (852)28578246; fax: (852) 25176912; jjiao@hku.hk, May–June issue 2010, v. 48, no. 3: 329–332.Search for more papers by this authorJiu Jimmy Jiao, Jiu Jimmy Jiao Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; (852)28578246; fax: (852) 25176912; jjiao@hku.hk, May–June issue 2010, v. 48, no. 3: 329–332.Search for more papers by this author Jacob Bear, Jacob Bear Department of Civil and Environmental Engineering, Technion-Israel Institute of Technology, Haifa, Israel. School of Engineering, Kinneret College on Sea of Galilee, Zemach, Israel; cvrbear@tx.technion.ac.ilSearch for more papers by this authorAlexander H.-D. Cheng, Corresponding Author Alexander H.-D. Cheng Department of Civil Engineering, University of Mississippi, MS 38677; acheng@olemiss.eduSearch for more papers by this authorVedat Batu, Vedat Batu URS Corporation, 100 South Wacker Drive, Chicago, IL 60606; vedat_batu@urscorpSearch for more papers by this authorChongxi Chen, Chongxi Chen Institute of Environmental Geology, China University of Geosciences, Wuhan, 430074, China.Search for more papers by this authorXingxing Kuang, Xingxing Kuang Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; (852)28578246; fax: (852) 25176912; jjiao@hku.hk, May–June issue 2010, v. 48, no. 3: 329–332.Search for more papers by this authorJiu Jimmy Jiao, Jiu Jimmy Jiao Department of Earth Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, China; (852)28578246; fax: (852) 25176912; jjiao@hku.hk, May–June issue 2010, v. 48, no. 3: 329–332.Search for more papers by this author First published: 22 June 2010 https://doi.org/10.1111/j.1745-6584.2010.00711.xCitations: 5 All equation numbers below 100 refer to equations in Chen et al. (2010). Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume48, Issue4July/August 2010Pages 486-493 RelatedInformation

Stability analysis of historic underground quarries

This work, carried out at the Department of Civil, Environmental and Territory Engineering and Architecture (DICATeA) of the University of Parma, analyzes the stability conditions of the ancient underground quarries of Viggiù (Varese, Italy). The objective of the study is to verify the actual structural predisposition to instability phenomena of the old Viggiù quarries, within the context of a historical and cultural valorization and recovery of the ancient ornamental stone quarries. These quarries, that are now completely abandoned, could be used as a tourist attraction and/or as a teaching environment. They are a wonderful example of industrial architecture by presenting an audacious composition of filled in trenches and room and pillar techniques. An experimental campaign based on in situ measurements and laboratory measurements has been carried out to characterize the rock mass and to determine rock mass mechanical features. A numerical model of the entire rock mass has been developed in order to analyze the stability of the entire underground openings. A preliminary monitoring phase has been realized, aimed at controlling abandoned rock structure movements at the most significant discontinuities. Some measurements of the vertical stress in the pillars and in the walls have been performed, as well, and used for the model calibration. Once the model has been calibrated, the analysis of the actual stress and deformation conditions has been evaluated, the stability condition of the entire structure computed and a forecasting analysis of any intervention that could be realized to guarantee the underground public access has been performed.

Graphene Nanocutting Through Nanopatterned Vacancy Defects

Graphene Nanocutting Through Nanopatterned Vacancy Defects Rhonda Jack1 2, Dipanjan Sen1 3, and Markus J. Buehler1 ∗ 1Laboratory for Atomistic and Molecular Mechanics (LAMM), Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, 77 Mass. Ave., Room 1-235A&B, Cambridge, MA, 02139, USA 2Department of Chemical Engineering, Hampton University, Hampton VA, USA 3Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Mass. Ave., Cambridge, MA, 02139, USA