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Full-Text Articles in Engineering

Series Solution Of The Autocatalytic Hydrolysis Of Cellulose, Rou-Xi Chen, Zhi Liu, Ji-Huan He Dec 2104

Series Solution Of The Autocatalytic Hydrolysis Of Cellulose, Rou-Xi Chen, Zhi Liu, Ji-Huan He

Ji-Huan He

The chemical degradation kinetics of
cellulose is of scientific interest, as well as its practical
importance in many industrial activities for optimal
design. Much work has been done recently to understand
the depolymerizaton of cellulose in homogeneous
acidic medium on the assumption of
autocatalytic hydrolysis with a positive feedback of
acid production from the degraded biopolymer. Series
solutions are obtained for concentrations of cellulose
chains and degraded cellulose chains by Taylor series
and variational iteration method. Depolymerization of
cellulose strongly depends upon the initial conditions,
and the concentration of cellulose chains changes
exponentially with a linear and square/cubic time ...


An Analysis Of The Barriers To And Drivers Of Green Public Procurement In Achieving A More Sustainable Construction Industry, Myles Keaveney, Paul Butler Mar 2104

An Analysis Of The Barriers To And Drivers Of Green Public Procurement In Achieving A More Sustainable Construction Industry, Myles Keaveney, Paul Butler

Conference papers

The public sector in Ireland possesses enormous purchasing power which has the strength to affect production and consumption trends in all market sectors. Environmental purchasing tools such as Green Public Procurement (GPP) are seen by many as the solution to greener purchasing decisions in order to obtain and maintain not only a more sustainable construction sector but also a more sustainable economy. The purpose of this research is to determine and examine the key barriers to and drivers of implementing GPP in public procurement departments in order to reduce the effect construction works have on the environment. There was limited ...


Design Of Microwave Lowpass Filters Based On Metamaterial Components, Mushtaq Ahmed Dec 2103

Design Of Microwave Lowpass Filters Based On Metamaterial Components, Mushtaq Ahmed

Mushtaq A. Alqaisy

No abstract provided.


Cmmi High Maturity, Jack Calis Jan 2021

Cmmi High Maturity, Jack Calis

Jack Calis

Software Education Service in Asia, Europe and Africa, CMMI High Maturity based process of software process consultants and training in by CMMI-High Maturity.


Csar 62 Spin Curve, Mohsen Azadi, Georgia Griggs, Glen De Villafranca, Gerald Lopez Dec 2018

Csar 62 Spin Curve, Mohsen Azadi, Georgia Griggs, Glen De Villafranca, Gerald Lopez

Protocols and Reports

No abstract provided.


Jpk.Pdf, Jpk Sonick Sep 2018

Jpk.Pdf, Jpk Sonick

jpk sonick

Kami menerima jasa refill tabung pemadam kebakaran untuk berbagai merk yang berada di pasaran dan untuk berbagai media


Evaluating Water Filtration And Disinfection For Household, Using Slow Sand Filters Plus Solar Disinfection, Mariana Demitry May 2018

Evaluating Water Filtration And Disinfection For Household, Using Slow Sand Filters Plus Solar Disinfection, Mariana Demitry

All Graduate Theses and Dissertations

In this research, a household water treatment system was built and evaluated as a trial for improving the drinking water quality of the Nile River for the low-income communities. The system consisted of household-scale slow sand filters, and transparent polyethylene terephthalate-bottles for solar disinfection. The evaluation of the system depended on the removal/inactivation of some surrogates for the reference pathogens, and turbidity. The reference pathogens are pathogens specified by the World Health Organization to evaluate the efficiency of the household water treatment options. They were chosen to represent the classes of pathogens in water (bacteria, viruses, protozoa). The surrogates ...


Evaluating The Impact Of External Carbon Source In Laboratory-Based Denitrification Rate Experiments, Jared Richens May 2018

Evaluating The Impact Of External Carbon Source In Laboratory-Based Denitrification Rate Experiments, Jared Richens

All Graduate Theses and Dissertations

Limitations in the quality of transformation rates used with water quality models such as QUAL2K have led to the need to identify methods that can effectively and accurately determine these rates. During the early stages of method development of a Utah Department of Environmental Quality (Utah DEQ) funded project seeking to identify such methods, it was determined that under certain situations external carbon amendment may be required to successfully determine denitrification rates.

The focus of this study was to evaluate the potential impacts that introducing external carbon sources may have on estimating the laboratory denitrification rates resulting from these methods ...


Methods For The Aerostructural Design And Optimization Of Wings With Arbitrary Planform And Payload Distribution, Jeffrey D. Taylor May 2018

Methods For The Aerostructural Design And Optimization Of Wings With Arbitrary Planform And Payload Distribution, Jeffrey D. Taylor

All Graduate Theses and Dissertations

The design of an aircraft wing often involves the use of mathematical methods for simultaneous aerodynamic and structural design. The goal of many of these methods is to minimize the drag on the wing. A variety of computer models exist for this purpose, but some require the use of expensive time and computational resources to give meaningful results. As an alternative, some mathematical methods have been developed that give reason ably accurate results without the need for a computer. However, most of these methods can only be used for wings with specific shapes and payload distributions. In this thesis, a ...


Thrust Augmented Nozzle For A Hybrid Rocket With A Helical Fuel Port, Joel H. Marshall May 2018

Thrust Augmented Nozzle For A Hybrid Rocket With A Helical Fuel Port, Joel H. Marshall

All Graduate Theses and Dissertations

A thrust augmented nozzle for hybrid rocket systems is investigated. The design lever-ages 3-D additive manufacturing to embed a helical fuel port into the thrust chamber of a hybrid rocket burning gaseous oxygen and ABS plastic as propellants. The helical port significantly increases how quickly the fuel burns, resulting in a fuel-rich exhaust exiting the nozzle. When a secondary gaseous oxygen flow is injected into the nozzle downstream of the throat, all of the remaining unburned fuel in the plume spontaneously ignites. This secondary reaction produces additional high pressure gases that are captured by the nozzle and significantly increases the ...


Size-Scale Effects Of Nonlinear Weir Hydraulics, Nathan L. Young May 2018

Size-Scale Effects Of Nonlinear Weir Hydraulics, Nathan L. Young

All Graduate Theses and Dissertations

Experimental physical model studies of hydraulic structures are often conducted to replicate flow behavior that may occur at the prototype scale. Geometric similitude is most often maintained between the prototype and model when studying reservoir and open channel hydraulic structures to account for the dominant gravity and inertia forces while other fluid forces (e.g., viscosity,surface tension) are assumed negligible. However, as model size and/or upstream head decreases, other fluid forces can exceed the negligible level and influence model flow behavior. This phenomenon is referred to as size-scale effects and is one potential origin of error in predicting ...


On Condition Monitoring Of High Switching Frequency Power Gan Converters With Adaptive Prognostics.Pdf, Mehrdad Biglarbegian Mar 2018

On Condition Monitoring Of High Switching Frequency Power Gan Converters With Adaptive Prognostics.Pdf, Mehrdad Biglarbegian

Mehrdad Biglarbegian

There is no doubt that in the future, a need for higher switching frequency is inevitable to extract the full benefits of reliable Gallium Nitride (GaN) device characteristics. Along with the reliability enhancement for GaN-based power converters, it is essential to monitor a precursor signature identification for diagnostics/prognostics techniques. With the availability of the most granular information deduced from advanced devices, a new data-driven scheme is proposed for system monitoring and possible lifetime extension of 400W power GaN converters at 100kHz. The approach relies on the real-time R_ds(on) data extraction from the power converter, and calibration of an ...


Multi-Purpose Generic Board For Hands-On Power Electronics Education Of Different Power Converter Topologies In Pv Applications.Pdf, Mehrdad Biglarbegian Mar 2018

Multi-Purpose Generic Board For Hands-On Power Electronics Education Of Different Power Converter Topologies In Pv Applications.Pdf, Mehrdad Biglarbegian

Mehrdad Biglarbegian

This paper presents the development of a multi-purpose generic board for hands-on power electronics education lab session focusing on Photovoltaic (PV) power electronics applications. The presented work tries to apply advanced methods for circuit designs and firmware developments of a DC/DC and a DC/AC converter for helping students to get familiar with system/subsystem level learning. The developed advanced converters can be used for interconnection of low voltage PV systems. Besides, the objective is to expedite the transferring of theory to practical purposes and to provide hands-on experiences for the development of power electronics systems.


Development Of Isolated Sensegan Current Monitoring For Boundary Conduction Mode Control Of Power Converters, Mehrdad Biglarbegian Mar 2018

Development Of Isolated Sensegan Current Monitoring For Boundary Conduction Mode Control Of Power Converters, Mehrdad Biglarbegian

Mehrdad Biglarbegian

This paper presents the design of the Isolated SenseGaN (Iso-SenseGaN) current sensing technique using Gallium Nitride (GaN) transistors. The isolation technique for the SenseGaN brings an opportunity for integration of sensing element with the power modules, and enables many control schemes in power converters. This could effectively open broader area for smart device monitoring, implementation of current controlling techniques at high frequency, and proper feedback for diagnostics/prognostics developments. In this work, the focus is on the practical challenges for the SenseGaN technique and presenting the inductor-based galvanic isolation. Using the current mirroring method, the authors defined a cursor for ...


Sample.Docx, Bepress Support 169, Willie Test Mar 2018

Sample.Docx, Bepress Support 169, Willie Test

bepress support 169

No abstract provided.


Correlation For Sessile Drop Evaporation Over A Wide Range Of Drop Volatilities, Ambient Gases And Pressures, Peter Kelly-Zion, Christopher J. Pursell, Gregory N. Wassom, Brenton V. Mandelkorn, Chris Nkinthorn Mar 2018

Correlation For Sessile Drop Evaporation Over A Wide Range Of Drop Volatilities, Ambient Gases And Pressures, Peter Kelly-Zion, Christopher J. Pursell, Gregory N. Wassom, Brenton V. Mandelkorn, Chris Nkinthorn

Engineering Faculty Research

A correlation for the evaporation of sessile drops over a very broad range of conditions was developed based on measured evaporation rate data obtained for drops of acetone, methanol, and six hydrocarbons ranging from hexane to isooctane, evaporating in air, helium, argon, and krypton, over a range of ambient pressures from 96 kPa to 615 kPa. The experiments were designed to produce a large variation in the rates of diffusion and buoyancy-induced (natural) convection of the vapor phase amongst the experimental conditions. The correlation, which fits the measurements with an RMS relative error of 5.2%, is a simple equation ...


In Operando Mechanism Analysis On Nanocrystalline Silicon Anode Material For Reversible And Ultrafast Sodium Storage, Lei Zhang, Xianluo Hu, Chaoji Chen, Haipeng Guo, Xiaoxiao Liu, Gengzhao Xu, Haijian Zhong, Shuang Cheng, Peng Wu, Jiashen Meng, Yunhui Huang, Shi Xue Dou, Hua-Kun Liu Mar 2018

In Operando Mechanism Analysis On Nanocrystalline Silicon Anode Material For Reversible And Ultrafast Sodium Storage, Lei Zhang, Xianluo Hu, Chaoji Chen, Haipeng Guo, Xiaoxiao Liu, Gengzhao Xu, Haijian Zhong, Shuang Cheng, Peng Wu, Jiashen Meng, Yunhui Huang, Shi Xue Dou, Hua-Kun Liu

Australian Institute for Innovative Materials - Papers

Presently, lithium-ion batteries (LIBs) are the most promising commercialized electrochemical energy storage systems. Unfortunately, the limited resource of Li results in increasing cost for its scalable application and a general consciousness of the need to find new type of energy storage technologies. Very recently, substantial effort has been invested to sodium-ion batteries (SIBs) due to their effectively unlimited nature of sodium resources. Furthermore, the potential of Li/Li+ is 0.3 V lower than that of Na/Na+, which makes it more effective to limit the electrolyte degradation on the outer surface of the electrode.[1] Nevertheless, one major obstacle ...


Editorial - Volume 1, 2018, Pp.1-2, Wojciech M. Budzianowski Feb 2018

Editorial - Volume 1, 2018, Pp.1-2, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


A Safety And Emissions Analysis Of Continuous Flow Intersections, Joshua Wolfgram Feb 2018

A Safety And Emissions Analysis Of Continuous Flow Intersections, Joshua Wolfgram

Environmental & Water Resources Engineering Masters Projects

Increasing travel demand, and challenges associated with high percentages of leftturning vehicles, have encouraged the introduction of significant infrastructure advancements. Certain alternative intersection designs, such as continuous flow intersections, median U-turns, and jughandles, eliminate the traditional protected lefterations of these intersection types have been studied to varying degrees, their safety and emissions-related impacts are not well-understood. This project develops a series of microsimulation models for two continuous flow intersections (CFI) located in Missouri and Colorado, and uses the Surrogate Safety Assessment Model (SSAM) to determine the impact of those designs on the location and type of conflicts compared to conventional ...


Magnetic Properties Of Gd Intermetallics, L. Petit, Z. Szotek, J. Jackson, M. Lüders, Durga Paudyal, Yaroslav Mudryk, Vitalij K. Pecharsky, K. A. Gschneidner, J. B. Staunton Feb 2018

Magnetic Properties Of Gd Intermetallics, L. Petit, Z. Szotek, J. Jackson, M. Lüders, Durga Paudyal, Yaroslav Mudryk, Vitalij K. Pecharsky, K. A. Gschneidner, J. B. Staunton

Ames Laboratory Accepted Manuscripts

Using first-principles calculations, based on disordered local moment theory, combined with the self-interaction corrected local spin density approximation, we study magnetic interactions in GdX intermetallics for X = Cu, Zn, Ga, Cd, and Mg. Our predicted magnetic orders and ordering temperatures both at zero and other pressures agree well with experiments including the large increase in the Curie temperature of GdCd under pressure that is shown by our own experimental measurements. From our results it emerges that the Ruderman-Kittel-Kasuya-Yosida interaction on its own can not explain the observed behaviour under pressure, and that the magnetic ordering mechanism is strongly influenced by ...


Prairie Strips Improve Biodiversity And The Delivery Of Multiple Ecosystem Services From Corn–Soybean Croplands, Lisa A. Schulte, Jarad Niemi, Matthew J. Helmers, Matt Liebman, J. Gordon Arbuckle, David E. James, Randall K. Kolka, Matthew E. O'Neal, Mark D. Tomer, John C. Tyndall, Heidi Asbjornsen, Pauline Drobney, Jeri Neal, Chris Witte Jan 2018

Prairie Strips Improve Biodiversity And The Delivery Of Multiple Ecosystem Services From Corn–Soybean Croplands, Lisa A. Schulte, Jarad Niemi, Matthew J. Helmers, Matt Liebman, J. Gordon Arbuckle, David E. James, Randall K. Kolka, Matthew E. O'Neal, Mark D. Tomer, John C. Tyndall, Heidi Asbjornsen, Pauline Drobney, Jeri Neal, Chris Witte

Jarad Niemi

Loss of biodiversity and degradation of ecosystem services from agricultural lands remain important challenges in the United States despite decades of spending on natural resource management. To date, conservation investment has emphasized engineering practices or vegetative strategies centered on monocultural plantings of nonnative plants, largely excluding native species from cropland. In a catchment-scale experiment, we quantified the multiple effects of integrating strips of native prairie species amid corn and soybean crops, with prairie strips arranged to arrest run-off on slopes. Replacing 10% of cropland with prairie strips increased biodiversity and ecosystem services with minimal impacts on crop production. Compared with ...


Producing Food, Feed And Energy: How Can Agriculture Do It All?, Emily Heaton, Lisa Schulte-Moore, Matt Helmers, Matt Liebman Jan 2018

Producing Food, Feed And Energy: How Can Agriculture Do It All?, Emily Heaton, Lisa Schulte-Moore, Matt Helmers, Matt Liebman

Matthew J. Helmers

Sustainable intensification of agricultural systems has been suggested—in addition to reducing waste and changing consumption habits—as a way to increase food, feed, fuel, and fiber security in the 21st century. Here we describe three primary strategies of agricultural intensification—conventional intensification, temporal intensification, and spatial intensification—and how they can be used to manage and integrate food and second-generation (2G) crop portfolios. While each strategy has individual merits, combining them to meet case-specific targets may achieve optimum results. Multiple experiments and examples from Iowa, USA illustrate the potential of combining these approaches for agroecological intensification that can provide ...


Nutrient Reduction Strategy: One Farm, Many Practices, Matthew J. Helmers Jan 2018

Nutrient Reduction Strategy: One Farm, Many Practices, Matthew J. Helmers

Matthew J. Helmers

With the release of the Iowa Nutrient Reduction Strategy (2013) in early 2013 there has been increased interest in what practices can be utilized by farmers to reduce nutrient export to downstream water bodies. As highlighted by the ISU Extension and Outreach Special Publication 235 (2013) there are many in-field, land use, and edge-of-field practices that have potential to reduce nutrient export. However, to reach the nutrient load reduction goals of 45% on both nitrate-N and phosphorus will require a combination of practices. As a result, there is a need to examine individual fields or small watersheds considering the range ...


Effects Of Nitrogen Application Timing And Source On Nitrate-Nitrogen Leaching And Crop Yields, Ainis Lagzdins, Matthew J. Helmers Jan 2018

Effects Of Nitrogen Application Timing And Source On Nitrate-Nitrogen Leaching And Crop Yields, Ainis Lagzdins, Matthew J. Helmers

Matthew J. Helmers

Subsurface drainage systems have been intensively installed in the Midwest to enhance agricultural production by removing excess water from naturally poorly drained and somewhat poorly drained agricultural soils. However, despite positive aspects, numerous studies have reported artificial subsurface drainage as one of the primary pathways for nitrate-nitrogen (nitrate-N) loss from agricultural fields to surface water.


Drainage Design For Improved Profits And Water Quality, Matthew J. Helmers, Greg Brenneman Jan 2018

Drainage Design For Improved Profits And Water Quality, Matthew J. Helmers, Greg Brenneman

Matthew J. Helmers

Subsurface drainage systems are an important component of agricultural production systems in many areas of Iowa. However, these drainage systems have been shown to deliver nitrate-N to downstream waterbodies. So, while subsurface drainage is important for crop production we also need to consider the design of these systems to minimize nitrate-N loss. Use of drainage water management in the design and operation of subsurface drainage systems is one potential method to reduce nitrate-N loss.


Modeling The Impacts Of Climate Change On Nitrogen Losses And Crop Yield In A Subsurface Drained Field, Zhaozhi Wang, Qhiming Qi, Lulin Xue, Melissa Bukovsky, Matthew J. Helmers Jan 2018

Modeling The Impacts Of Climate Change On Nitrogen Losses And Crop Yield In A Subsurface Drained Field, Zhaozhi Wang, Qhiming Qi, Lulin Xue, Melissa Bukovsky, Matthew J. Helmers

Matthew J. Helmers

The effect of climate change on crop production and nitrate-nitrogen (NO3-N) pollution from subsurface drained fields is of a great concern. Using the calibrated and validated RZWQM2 (coupled with CERES-Maize and CROPGRO in DSSAT), the potential effects of climate change and elevated atmospheric CO2 concentrations (CO2) on tile drainage volume, NO3-N losses, and crop production were assessed integrally for the first time for a corn-soybean rotation cropping system near Gilmore City, Iowa. RZWQM2 simulated results under 20-year observed historical weather data (1990–2009) and ambient CO2 were compared to those under 20-year projected future meteorological data (2045–2064) and elevated ...


Ionic Depletion At The Crystalline Gibbs Layer Of Peg-Capped Gold Nanoparticle Brushes At Aqueous Surfaces, Wenjie Wang, Honghu Zhang, Surya Mallapragada, Alex Travesset, David Vaknin Jan 2018

Ionic Depletion At The Crystalline Gibbs Layer Of Peg-Capped Gold Nanoparticle Brushes At Aqueous Surfaces, Wenjie Wang, Honghu Zhang, Surya Mallapragada, Alex Travesset, David Vaknin

Surya K. Mallapragada

In situ surface-sensitive x-ray diffraction and grazing incidence x-ray fluorescence spectroscopy (GIXFS) methods are combined to determine the ionic distributions across the liquid/vapor interfaces of thiolated-polyethylene-glycol–capped gold nanoparticle (PEG-AuNP) solutions. Induced by the addition of salts (i.e., Cs2SO4) to PEG-AuNPs solutions, two-dimensional hexagonal lattices of PEG-AuNPs form spontaneously at the aqueous surfaces, as is demonstrated by x-ray reflectivity and grazing incidence small-angle x-ray scattering. By taking advantage of element specificity with the GIXFS method, we find that the cation Cs+ concentration at the crystalline film is significantly reduced in parts of the PEG-AuNP film compared with that ...


Electrical Stimulation For Enhanced Denitrification In Woodchip Bioreactors: Opportunities And Challenges, J. Y. Law, Michelle L. Soupir, D. Raj Raman, T. B. Moorman, Say K. Ong Jan 2018

Electrical Stimulation For Enhanced Denitrification In Woodchip Bioreactors: Opportunities And Challenges, J. Y. Law, Michelle L. Soupir, D. Raj Raman, T. B. Moorman, Say K. Ong

D. Raj Raman

Woodchip bioreactors are being implemented for the removal of nitrates in groundwater and tile water drainage. However, low nitrate removals in denitrifying woodchip bioreactors have been observed for short hydraulic retention time (HRT) and low water temperature (°C). One potential approach to improve woodchip bioreactor performance is to provide an alternative and readily available electron source to the denitrifying microorganisms through electrical stimulation. Previous work has demonstrated the capability of bio-electrochemical reactors (BER) to remove a variety of water contaminants, including nitrate, in the presence of a soluble carbon source. The objective of this study was to evaluate the denitrification ...


Performance Of Chicks Subjected To Thermal Challenge, Patrícia Ferreira Ponciano Ferraz, Tadayuki Yanagi Junior, Renato Ribeiro De Lima, Gabriel Araújo E Silva Ferraz, Hongwei Xin Jan 2018

Performance Of Chicks Subjected To Thermal Challenge, Patrícia Ferreira Ponciano Ferraz, Tadayuki Yanagi Junior, Renato Ribeiro De Lima, Gabriel Araújo E Silva Ferraz, Hongwei Xin

Hongwei Xin

The objective of this work was to evaluate the effect of thermal challenge at different intensities and durations on the production responses of 3 to 21-day-old broiler chickens. Two hundred and ten Cobb chicks were subjected to dry-bulb temperatures (tdb) of 27, 30, 33, or 36°C for the duration of 0, 1, 2, 3, or 4 days from the second day of life onwards. The experiment was carried out in four identical environmentally-controlled wind tunnels. Data on body mass (BM), feed intake (FI), and water intake (WI), all in grams, were monitored daily; and body weight gain (BWG), in ...


Sow Lying Behaviors Before, During And After Farrowing, F. Lao, T. M. Brown-Brandl, G. Teng, Kai Liu, Hongwei Xin Jan 2018

Sow Lying Behaviors Before, During And After Farrowing, F. Lao, T. M. Brown-Brandl, G. Teng, Kai Liu, Hongwei Xin

Hongwei Xin

Piglet pre-weaning mortality remains a considerable challenge for the swine industry, representing one of the key areas where animal well-being and economical interest coincide. Sows and piglets carry out a complex series of behaviors during the farrowing/lactation period. These behaviors during the first few days after parturition are extremely important for piglet survival, and they can be greatly impacted by the farrowing system, environment, and/or management. The risk of sow crushing is much greater for piglets when the sow changes her postures. Limited studies have investigated the effects of environment on sow’s posture changes or basic understanding ...