bluuebunny/crossref_metadata_2025 huggingface dataset:
Essential oils enhance the toxicity of permethrin against Aedes aegypti and Anopheles gambiae
Authors: GROSS A. D. , NORRIS E. J. , KIMBER M. J. , BARTHOLOMAY L. C. , COATS J. R.
Published: November 2016

Insecticide resistance and growing public concern over the safety and environmental impacts of some conventional insecticides have resulted in the need to discover alternative control tools. Naturally occurring botanically‐based compounds are of increased interest to aid in the management of mosquitoes. Susceptible strains of Aedes aegypti (Linnaeus) (Diptera: Culicidae) and Anopheles gambiae (Meigen) (Diptera: Culicidae) were treated with permethrin, a common type‐I synthetic pyrethroid, using a discriminate dose that resulted in less than 50% mortality. Piperonyl butoxide (PBO) and 35 essential oils were co‐delivered with permethrin at two doses (2 and 10 µg) to determine if they could enhance the 1‐h knockdown and the 24‐h mortality of permethrin. Several of the tested essential oils enhanced the efficacy of permethrin equally and more effectively than piperonyl butoxide PBO, which is the commercial standard to synergize chemical insecticide like pyrethroids. PBO had a strikingly negative effect on the 1‐h knockdown of permethrin against Ae. aegypti, which was not observed in An. gambiae. Botanical essential oils have the capability of increasing the efficacy of permethrin allowing for a natural alternative to classic chemical synergists, like PBO.
Global regulatory framework for production and marketing of crops biofortified with vitamins and minerals
Authors: Mejia Luis A. , Dary Omar , Boukerdenna Hala
Published: November 2016

Biofortification of crops is being introduced in several countries as a strategy to reduce micronutrient deficiencies. Biofortified products, with increased contents of micronutrients, are currently produced by conventional plant breeding, genetic modification, or nutrient‐enhanced fertilization. Corn, rice, wheat, beans, pearl millet, sweet potato, and cassava have been biofortified with increased contents of provitamin A carotenoids, iron, or zinc. However, regulatory considerations are rare or nonexistent. The objective of this paper is to review the regulatory framework for production and marketing of biofortified crops in countries that have adopted this strategy. The information was identified using Internet search engines and websites of health and nutrition organizations and nongovernmental organizations and by consulting scientists and government authorities. Thus far, biofortified products introduced in Latin America, Africa, and Asia have been produced only by conventional breeding. Cultivars using other techniques are still under testing. The production and marketing of these products have been conducted without regulatory framework and under limited government control or regulatory guidance. Nevertheless, some countries have integrated biofortified crops into their nutrition agendas. Although improvements by conventional breeding have not been subject to regulations, when biofortification becomes expanded by including other techniques, an appropriate regulatory framework will be necessary.
Measurement of skin surface biomakers by Transdermal Analyses Patch following different in vivo models of irritation: a pilot study
Authors: Falcone D. , Spee P. , Salk K. , Peppelman M. , van de Kerkhof P. C. M. , van Erp P. E. J.
Published: November 2016

Background/Purpose

FibroTx Transdermal Analyses Patch (TAP) is a novel technology for non‐invasive measurements of protein biomarkers on the skin surface, in vivo. The aim of this study was to explore the potential of TAP in detecting skin surface biomarkers following mild perturbations, in vivo, using two experimental models: tape stripping, mimicking acute barrier disruption, and histamine iontophoresis, mimicking acute and local inflammation at minimal skin barrier insult.

Methods

Tape stripping and histamine iontophoresis were performed in two separate experiments on the volar forearm of healthy volunteers (n = 27 and n = 10, respectively). Biomarker levels were assessed with TAP at baseline and up to 72 h after stimulation. Functional (transepidermal water loss –TEWL– and a* value) and morphological (confocal reflectance microscopy –RCM) assessments were added in the tape stripping and histamine iontophoresis experiments, respectively.

Results

Cytokines IL‐1α and IL‐1RA and the antimicrobial peptide hBD‐1 showed distinct dynamics, despite substantial inter‐individual variation in levels, with an increase following tape stripping and a decrease following histamine iontophoresis. These dynamics could be related to the assessments made by TEWL and RCM. In the tape stripping experiment, additional biomarkers could be detected.

Conclusion

TAP measurements, especially IL‐1α, IL‐1RA, and hBD‐1, from the skin surface were sensitive enough for monitoring dynamic changes in the skin in the two models of skin perturbation. We conclude that TAP holds promise for non‐invasively unraveling the dynamics of processes related to skin perturbation and repair.
What Do We Value Most in Schools? A Study of Preference Rankings of School Attributes
Authors: Hassan Mamdouh , Geys Benny
Published: November 2016

Objectives

A key question in education policy as well as individuals’ school choice involves the characteristics of schools we value most. It is thereby important to understand any heterogeneity in parents’, teachers’, and school principals’ preference rankings driven by their education level, gender, and age.

Method

In this article, we propose a survey‐based approach to examine preference rankings of diverse school attributes, which accounts for tradeoffs required in real‐world choice situations.

Results

Our results indicate that stakeholders on average rank the “ethical” aspects of schools (such as pupil and staff happiness and equality of opportunities) above their “efficiency” aspects (such as academic achievement or school size). Yet, respondents’ role in the school as well as their education level, gender, and age influence observed preference rankings.

Conclusions

To avoid biased inferences, survey designs on school preferences should account for the fact that real‐world choices in favor of one particular characteristic often imply giving up at least some others. Doing so, we show that parents, teachers, and school principals appear to disagree with the predominant consideration awarded to academic achievement in current education policies.
A Database of Optimal Airfoils for Axial Compressor Throughflow Design
Authors: Schnoes Markus , Nicke Eberhard
Published: November 2016

Airfoil shapes tailored to specific inflow conditions and loading requirements can offer a significant performance potential over classic airfoil shapes. However, their optimal operating range has to be matched thoroughly to the overall compressor layout. This paper describes methods to organize a large set of optimized airfoils in a database and its application in the throughflow design. Optimized airfoils are structured in five dimensions: inlet Mach number, blade stagger angle, pitch–chord ratio, maximum thickness–chord ratio, and a parameter for aerodynamic loading. In this space, a high number of airfoil geometries are generated by means of numerical optimization. During the optimization of each airfoil, the performance at design and off-design conditions is evaluated with the blade-to-blade flow solver MISES. Together with the airfoil geometry, the database stores automatically calibrated correlations which describe the cascade performance in throughflow calculation. Based on these methods, two subsonic stages of a 4.5-stage transonic research compressor are redesigned. Performance of the baseline and updated geometry is evaluated with 3D CFD. The overall approach offers accurate throughflow design incorporating optimized airfoil shapes and a fast transition from throughflow to 3D CFD design.
On a Discrete Chaos Induction Via an Aperiodic Kicks Pattern
Authors: Nategh Mehdi , Baleanu Dumitru , Reza Valinejad Mohammad
Published: November 2016

In this work, a class of kicked systems perturbed with an irregular kicks pattern is studied and formation of a chaos in the senses of Devaney and Li–Yorke in the corresponding discretized system is investigated. Beside a discussion on chaotic stability, an example is presented. Then, the existence of a period three orbit of a 2D map which governs a class of dynamic problems on time scales is studied. As an application, a chaotic encryption scheme for a time-dependent plain text with the help of chaos induction in the sense of Li–Yorke is presented.
An Online Tuning Method for Robust Control of Multivariable Nonlinear Processes With Nonanalytical Modules and Time Delay
Authors: Wang Jiqiang , Shen Hao , Song Zhitao
Published: November 2016

Control design for multivariable nonlinear systems has cultivated into a mature research area. A variety of control design methodologies have been well established. In most of the approaches, however, it is implicitly assumed that an analytically mathematical model can be available. This is not always feasible since in many practical control problems, system dynamics may be represented by nonanalytical modules, such as look-up tables, c or Fortran codes, etc. As a consequence, conventional methods can only be performed after analytical models are obtained. In this paper, an approach is proposed where the nonanalytical modules can be handled directly. Important results are obtained on optimal control laws and their implementation; robust control is achieved using a new online tuning method; input saturation and stability issues are also discussed. A numerical study is provided to validate the effectiveness of the proposed method.
A Control-Theoretic Model for Human Time-Motion Evaluation in Pick-and-Place Operations
Authors: Wang Chao , Ravani Bahram , Hess Ronald A.
Published: November 2016

This paper deals with physical modeling of human hand–eye coordinated movement for applications in time-motion study of pick-and-place operations. Time-motion studies typically use experimentations to closely examine each segment of a worker's pick-and-place movements in order to design a more optimized operation. This paper presents two different methods that can replace the need for experimentation or estimation in the time motion process with control-theoretic models. The first method is a control-theoretic physical model of the human hand–eye coordinated movement in performing a pick-and-place operation. It is based on an extension of control theoretic models of airplane pilots. The second method combines two existing techniques developed in the literature for different purposes. It is shown in this paper that the combination of these two existing methods provides for an alternative approach that can be used for time-motion studies related to the human pick-and-place operation. Using simple experimentation, it is shown that both methods provide reasonable model-based representation of time motion studies for pick-and-place tasks. In developing the physical model, a method based on the use of the quantitative feedback theory (QFT) is also developed for tuning the physical model that can be utilized in making the model specific to different applications involving human hand–eye coordinated movements. Furthermore, the physical model is applied in a predictive fashion and it is shown that it can successfully estimate the movement time for manual pick-and-place tasks found in some industrial applications.
Estimating Building Envelope Thermal Characteristics From Single-Point-in-Time Thermal Images
Authors: Alshatshati Salahaldin , Hallinan Kevin P. , Brecha Robert J.
Published: November 2016

Energy efficiency programs implemented by utilities in the U.S. have rendered savings costing on average $0.03/kWh [1]. This cost is still well below energy generation costs. However, as the lowest cost energy efficiency measures are adopted, the cost effectiveness of further investment declines. Thus, there is a need to develop large-scale and relatively inexpensive energy auditing techniques to more efficiently find opportunities for savings. Currently, on-site building energy audits process are expensive, in the range of US$0.12/sf – $0.53/sf, and there is an insufficient number of professionals to perform the audits. Here we present research that addresses at community-wide scales the characterization of building envelope thermal characteristics via drive-by and fly-over GPS linked thermal imaging. A central question drives this research: Can single point-in-time thermal images be used to infer R-values and thermal capacitances of walls and roofs? Previous efforts to use thermal images to estimate R-values have been limited to stable exterior weather conditions. The approach posed here is based upon the development of a dynamic model of a building envelope component with unknown R-value and thermal capacitance. The weather conditions prior to the thermal image are used as inputs to the model. The model is solved to determine the exterior surface temperature, ultimately predicted the temperature at the thermal measurement time. The model R-value and thermal capacitance are tuned to force the error between the predicted surface temperature and the measured surface temperature from thermal imaging to be near zero. The results show that this methodology is capable of accurately estimating envelope thermal characteristics over a realistic spectrum of envelope R-values and thermal capacitance present in buildings nationally. With an assumed thermal image accuracy, thermal characteristics are predicted with a maximum error of respectively 20% and 14% for high and low R-values when the standard deviation of outside temperature over the previous 48 hours is as much as 5°C. Experimental validation on a test facility with variable surface materials was attempted under variable weather conditions, e.g., where the outdoor air temperature experiences varying fluctuations prior to imaging. The experimental validation realized errors less than 20% in predicting the R-value even when the standard deviation of outdoor temperature over the 48 hours prior to a measurement was approximately 5°C.
Development of an Exhaust Enthalpy Control Unit to Augment Combined Heat and Power Applications
Authors: Hack Richard L. , Sullivan-Lewis Elliot , McDonell Vince G.
Published: November 2016

One of the primary challenges facing DG/CHP systems involves effective design and operational match with potential end applications. A key weakness in the deployment of many DG/CHP systems is the inability of the installed system to properly match up with the actual load that it is being asked to serve. In general, it is difficult to optimally match the demand of both electricity and thermal requirements with a single system as a result of variations in loads with season, site operational changes, and other factors. It seems apparent that improved flexibility in how a DG/CHP system’s electricity/thermal production ratio is established will provide more flexibility in how a given system can meet a given demand profile. While examples of temperature increase via supplemental burners are available for small scale systems, a system to control both exhaust temperature (increase and decrease) and overall flow rate is not available. This paper describes the results of a multi-year program sponsored by the California Energy Commission to develop and demonstrate an exhaust energy tailoring system that will provide flexibility in both temperature adjustments and overall exhaust flow to meet the requirements of various heat recovery systems while providing low emission when coupled with a commercial distributed generation “prime mover”. The program integrated a multi-stage Rich/Quick-mix/Lean combustion system operating on the vitiated exhaust stream from a Capstone Model “iCHP65” to provide flexible wide range control of the exhaust energy and quality. Additionally, the integrated system reduced both the criteria pollutant concentration levels and emission rates over the Capstone unit alone. This paper describes the development of the unique vitiated air combustor system as well as full scale test results.
Forecasting Building Energy Demands for New York City With a Coupled Weather-Building Energy Model
Authors: Ortiz Luis E. , Gonzalez Jorge E. , Gutierrez Estatio , Arend Mark , Legbandt Thomas , Neufeld Stephen
Published: November 2016

Major metropolitan centers experience challenges during management of peak electrical loads, typically occurring during extreme summer events. These peak loads expose the reliability of the electrical grid and customers may incur in additional charges for peak load management in regulated demand-response markets. This opens the need for the development of analytical tools that can inform building managers and utilities about near future conditions so they are better able to avoid peak demand charges, reducing building operational costs. In this article, we report on a tool and methodology to forecast peak loads at the City Scale using New York City (NYC) as a test case. The city of New York experiences peak electric demand loads that reach up to 11 GW during the summertime, and are projected to increase to over 12 GW by 2025, as reported by the New York Independent System Operator (NYISO). The forecast is based on the Weather Research and Forecast model version 3.5, coupled with a building environment parameterization and building energy model. Urban morphology parameters are assimilated from the New York Primary Land Use Tax Lot Output (PLUTO), while the weather component of the model is initialized daily from the North American Mesoscale (NAM) model. A city-scale analysis is centered in the summer months of June-July 2015 which included an extreme heat event (i.e. heat wave). The 24-hr city-scale weather and energy forecasts show good agreement with the archived data from both weather stations records and energy records by NYISO.
Effect of Viscosity Variations on Charge and Discharge Time of a Sulfur-Based Thermal Energy Storage System
Authors: Baghaei Lakeh Reza , Nithyanandam Karthik , Barde Amey , Tse Louis , Wirz Richard E.
Published: November 2016

Most of the renewable energy sources, including solar and wind suffer from significant intermittency due to day/night cycles and unpredictable weather patterns. On the other hand increasing share of renewable sources imposes additional stability risks on the power grid. Increased share of solar energy in power generation during noon along with increased power demand during afternoon peak hours generates a significant risk on the stability of power grid. Energy Storage systems are required to enable the renewable energy sources to continuously generate energy for the power grid and enhance the stability of future grid that benefits from more renewable sources. Thermal Energy Storage (TES) is one of the most promising forms of energy storage. Although round trip efficiency is relatively high in thermal storage systems, heat transfer is a well-known problem of most TES systems that use solid state or phase change. Insufficient heat transfer may significantly impact the performance of the TES system. The TES system of this study utilizes molten sulfur as the storage medium. Although thermal conductivity of molten sulfur is relatively low, the sulfur-based TES system benefits from enhanced heat transfer due to the presence of buoyancy-driven flows. In this study, the effect of natural convection on the heat transfer characteristics of a sulfur-based isochoric TES system is studied computationally and theoretically. It turns out that the viscosity of sulfur in the temperature range of this study (250–400 °C) varies by two orders of magnitude. A computational model was developed to investigate the effect of viscosity variations on the buoyancy-driven flow and corresponding charge and discharge times. The computational model is developed using an unsteady Finite Volume Method by a commercially available CFD package. The results of this study show that the heat transfer process in the isochoric TES element is highly impacted by natural convection. The viscous flow of molten sulfur near the boundaries of the isochoric TES element leads to different charge and discharge times. The discharge time is almost two times longer than the charge time due to formation of a viscous layer of elemental sulfur near the heat transfer surface. The viscous layer of sulfur decreases the activity of the buoyancy-driven flow and decreases the heat transfer rate during discharge cycle. The computational model was validated by comparing the results of a representative case with experimental data.
Measurement of the Basic Properties of Ternary Eutectic Chloride Salts Used as High Temperature Heat Transfer Fluids and Thermal Storage Media
Authors: Dehghani Ghazal , Xu Xiankun , Li Peiwen
Published: November 2016

Concentrated solar power (CSP) technologies tend to work at more and more high temperatures, which correspondingly need a high temperature heat transfer fluid (HTF) to transmit the heat from solar concentrator to power plant. The objective of this work is to study heat capacities of a HTF which can work at upper limit temperature of around 850 °C. The ideal HTF should have low melting temperature and be thermally stable at high temperatures. High specific heat capacity is also favorable. The eutectic ternary salt mixtures studied in this work are formed by NaCl, KCl and ZnCl2. The heat capacity, heat of fusion, and melting temperatures of three salt mixtures were measured by using Differential Scanning Calorimetry (DSC)/Thermal Gravimetric Analysis (TGA) simultaneously. The accuracy of the measurements was validated by measuring three metals, Indium, Tin, and Zinc, which have standard reference data. Each of the three eutectic mixtures by NaCl-KCl-ZnCl2 ternary system had 10 to 11 samples tested for heat of fusion, the melting point, and heat capacity. Mixing rule from literature was used to estimate the heat capacity of the new HTF, which showed very good agreement to experimental data.
Solar Water Distillation Using Paraffin Wax as Phase Change Material
Authors: Sudheer Bellam , Vijaya Kumar Reddy K. , Gugulothu Ravi , Tallapragada V. S. S. P. Sashank , Bhavirisetti Manikanta
Published: November 2016

All life on earth depends on energy and the cycling of carbon. Energy is essential for economic and social development and also poses an environmental challenge. The world’s dependence on fossil fuels began approximately 200 years ago. Availability of fossil energy resources, peak oil era and this is the time for end of the fossil fuel era, price and environmental impact and various renewable resources and use of it.

The twenty first century is rapidly becoming the perfect energy storm, modern society is faced with volatile energy prices and growing environmental concerns as well as energy supply and security issues. Solar and wind energy are now providing the lowest cost options for economic and community development in rural regions around the globe. Energy and water are the key to modern life and provide the basis necessary for sustained economic development. Due to a growing world population and increasing modernization global energy demand is raising during the current century. Finding the sufficient supplies of clean and sustainable energy for the future is the global society’s most challenge for this century. The future will be depends on a renewable sources such as solar, wind and biomass.

There are large numbers of phase change materials (PCM’S) that melt and solidify at wide range of temperatures, making them attractive in a number of applications. PCMs have been widely used in latent heat thermal storage systems for heat pumps, solar engineering and spacecraft thermal control applications. The use of PCMs for heating and cooling applications for buildings has been investigated within the past decade. The experimental results computed in the field of water distillation process using solar energy in the presence of energy storage materials i.e paraffin wax are discussed in this paper.
Optimal Capacity Sizing for a Completely Green Village With Programmable Appliances
Authors: Ugirumurera Juliette , Haas Zygmunt J.
Published: November 2016

Current trends show that renewable energy production costs continue to decrease with time, so that renewable energy sources (RES) are becoming more suitable as electricity sources. In addition to their environmental benefits, RES are especially appropriate for remote areas, where the expansion of existing power grid is impractical and fuel transportation for thermal generators is too expensive. In this regard, our work studies the optimal capacity sizing for a completely green village (CGV), which is an isolated residential microgrid (MG) whose power is entirely generated by RES. In particular, we consider a neighborhood composed of smart homes that contain programmable appliances, whose operations can be interrupted or automatically scheduled in time. Though there are many works in literature that investigate MG optimal capacity sizing, to our knowledge, our work is the first that utilizes the scheduling of programmable appliance to minimize MG investment costs. To establish the effectiveness of our method, we compare an optimal MG capacity sizing algorithm that utilizes appliances’ programmability (Opt-P) with an algorithm that places appliances into operation as soon as they are ready without shifting in time or preempting their operation (NoSch-P). Our simulation results show that Opt-P reduces the investment cost by at least 42% compared to NoSch-P, when the ratio between the energy storage investment cost per kWh and the RES’ investment cost per kW is greater or equal to 10.
Analysis of Off-Design Behavior of a Solar-Fossil Hybrid Combined Cycle Plant Using a Small Particle Heat Exchange Receiver (SPHER) With a Variable Guide Vane Gas Turbine
Authors: Virgen Matthew Miguel , Miller Fletcher
Published: November 2016

Two significant goals in solar plant operation are lower cost and higher efficiencies. This is both for general competitiveness of solar technology in the energy industry, and also to meet the US DOE Sunshot Initiative Concentrating Solar Power (CSP) cost goals [1]. We present here an investigation on the effects of adding a bottoming steam power cycle to a solar-fossil hybrid CSP plant based on a Small Particle Heat Exchange Receiver (SPHER) driving a gas turbine as the primary cycle. Due to the high operating temperature of the SPHER being considered (over 1000 Celsius), the exhaust air from the primary Brayton cycle still contains a tremendous amount of exergy. This exergy of the gas flow can be captured in a heat recovery steam generator (HRSG), to generate superheated steam and run a bottoming Rankine cycle, in a combined cycle gas turbine (CCGT) system. A wide range of cases were run to explore options for maximizing both power and efficiency from the proposed CSP CCGT plant. Due to the generalized nature of the bottoming cycle modeling, and the varying nature of solar power, special consideration had to be given to the behavior of the heat exchanger and Rankine cycle in off-design scenarios.

Variable guide vanes (VGVs), which can control the mass flow rate through the gas turbine system, have been found to be an effective tool in providing operational flexibility to address the variable nature of solar input. The effect VGVs and the operating range associated with them are presented. Strategies for meeting a minimum solar share are also explored. Trends with respect to the change in variable guide vane angle are discussed, as well as the response of the HRSG and bottoming Rankine cycle in response to changes in the gas mass flow rate and temperature. System efficiencies in the range of 50% were found to result from this plant configuration. However, a combustor inlet temperature (CIT) limit lower than a turbine inlet temperature (TIT) limit leads two distinct Modes of operation, with a sharp drop in both plant efficiency and power occurring when the air flow through the receiver exceeded the (CIT) limit, and as a result would have to bypass the combustor entirely and enter the turbine at a significantly lower temperature than nominal. Until that limit is completely eliminated through material or design improvements, this drawback can be addressed through strategic use of the variable guide vanes. Optimal operational strategy is ultimately decided by economics, plant objectives, or other market incentives.
Heat Transfer Behavior of Sulfur for Thermal Storage Applications
Authors: Nithyanandam Karthik , Barde Amey , Tse Louis , Baghaei Lakeh Reza , Wirz Richard
Published: November 2016

Efficient and cost-effective thermal energy storage system plays an important role in energy conservation. Elemental sulfur, the thirteenth most abundant element on earth, is actively being researched as a potential thermal storage medium due to its high energy storage density and low cost. The present work investigates the heat transfer behavior of elemental sulfur at temperatures between 50 degree Celsius and 250 degree Celsius. A shell and tube heat exchanger configuration with sulfur stored inside the tubes and heat transfer fluid flowing over the tubes through the shell is considered. A detailed computational model solving for the conjugate heat transfer and solid-liquid phase change dynamics of the sulfur based thermal energy storage system is developed to elucidate the complex interplay between the governing heat transfer and fluid flow phenomena during charge and discharge operations. The developed numerical model is compared with experimental results and a systematic parametric analysis of the effects of various design parameters on the performance of the thermal storage system is reported.
Annual Simulation of the Thermal Performance of Solar Power Plant for Electricity Production Using TRNSYS
Authors: Ahmed Mohamed H. , Giaconia Alberto , Amin Amr M. A.
Published: November 2016

The process of generating electricity using solar energy took a great interest in the recent period for its contribution to the reduction of the fossil fuel consumption and the harmful emissions to the environment. The main task of this article is to simulate the thermal performance of a solar power plant for electricity production using a parabolic trough concentrator for accumulating the solar heat. The plant includes a stratified storage tank, steam generator, steam turbine and an electric generator. The simulation studies the effect of the design parameters of the solar field and the storage tank on the annual performance of a 1 MWe solar electric power plant. The simulation platform TRNSYS was used to model the solar power plant including the solar concentrator field, the storage tank, and the steam generator. The simulation predicts the instantaneous and annual heat energy collected by the solar concentrator and the heat energy rate supplied, extracted, and stored in the storage tank. It predicts also the rate and the quality of the steam produced. This analysis was applied to four sites in Egypt to study the effect of the solar radiation on the energy produced in those sites.
Microwave Plasma Gasification for Enhanced Oil Recovery and Sustainable Waste Management
Authors: Panicker Philip K. , Magid Amani
Published: November 2016

This paper presents qualitative evidence to support the application of microwave induced plasma gasification (MIPG) technology for converting municipal solid wastes (MSW) to syngas and to use it for enhanced oil recovery (EOR). The target for the case study of this paper is the United Arab Emirates, which is a major producer and exporter of petroleum. The main EOR method employed by the UAE’s oil companies is the miscible gas flooding method, whereby natural gas or carbon dioxide is injected into the oil reservoirs to boost the oil pressure, reduce the viscosity of the oil and to increase the pumping rates. UAE purchases natural gas for power production and EOR from its neighbor, Qatar, which makes the UAE a net importer of natural gas and a major consumer of energy, while reducing the national income from the oil sales. The UAE is looking at ways to boost its oil production and to reduce the usage of natural gas, including the injection of carbon dioxide, nitrogen and steam generated by concentrated solar power.

UAE and the other Arabian Gulf nations have some of the highest per capita rates of production of domestic waste. Landfilling is the prevalent form of waste disposal for industrial, commercial and residential waste. Incineration-type waste-to-energy power plants are being constructed, but they are not the most effective solution due to cost and environmental reasons.

This paper proposes a solution that covers the two problems with one technology, namely MIPG of MSW. MIPG is shown to be the most efficient method of gasification available, as it uses much less energy for producing and sustaining the plasma than other techniques, and produces a much cleaner syngas than thermochemical gasification schemes. The syngas can be used for electricity generation or for making fuels and raw materials in the Fischer-Tropsch or similar processes. In this proposal, MIPG will be used to turn MSW, sewage sludge and biomass wastes into syngas. A part of the syngas will be used to produce electricity to power the petroleum extraction processes, while the carbon dioxide formed in this combustion of syngas can be captured and used for EOR in deep oil wells, which also functions as a form of sequestration of carbon. In addition, syngas can be turned into methane and synthetic natural gas using the Fischer-Tropsch or Sabatier process and then pumped into the oil wells. Some of the petroleum extracted can also be gasified using the MIPG method for the production of synthetic natural gas. Thus, the dependence on natural gas imports will be eliminated, while also achieving zero landfill targets.
Optical Performance of Bladed Receivers for CSP Systems
Authors: Wang Ye , Asselineau Charles-Alexis , Coventry Joe , Pye John
Published: November 2016

Bladed structures offer an approach to improve the efficiency of conventional concentrating solar power (CSP) cylindrical receivers, due to improved light-trapping via the cavity effect, and by allowing more tubes to be compressed into a smaller aperture, enabling the flux on the aperture to be increased without exceeding the peak flux limitation on individual tubes. In this paper, we present an optical model of a hypothetical bladed receiver mounted on the tower of the Sandia National Solar Thermal Test Facility (NSTTF). We examine the impact of receiver geometric parameters including receiver width, receiver height, number of blades, blade depth and blade angle, through analysis using ‘Tracer’, an open-source Python-based Monte Carlo ray tracing library. Validation of Tracer is provided, through comparison with results from other tools. At the optimal configuration, 15 blades with a depth of 4.5 m and angle of 63.9° from the vertical are spaced vertically over a 9.6×9.6 m back wall. In this configuration, the peak flux occurs on the back plane and is considerably lower than a corresponding flat receiver. The design-point receiver optical efficiency increases from 93.8% for a flat receiver to 98.5% for the bladed configuration, and is shown to be robust to sun position changes.
Sensitivity Analysis and Computational Optimization of Fuel Reformer
Authors: Raoufi Arman , Kapadia Sagar , Newman James C.
Published: November 2016

In this study, the catalytic combustion of methane is numerically investigated using an unstructured, implicit, fully coupled finite volume approach. Nonlinear system of equations is solved by Newton’s method. The catalytic partial oxidation of methane over both platinum and rhodium catalysts are studied three-dimensionally. Eight gas-phase species (CH4, CO2, H2O, N2, O2, CO, OH and H2) are considered for the simulation. Surface chemistry is modeled by detailed reaction mechanisms including 24 heterogeneous reactions with 11 surface-adsorbed species for Pt catalyst and 38 heterogeneous reactions with 20 surface-adsorbed species for Rh catalyst. The numerical results are compared with the experimental data and good agreement is observed. The performance of the fuel reformer is analyzed for two different catalysts. The sensitivity analysis for the reactor is performed using three different approaches: finite difference, direct differentiation and adjoint method. The design cycle is performed using two gradient-based optimization algorithms to improve the value of the implemented cost function and optimize the reactor performance.
Synthesis and Performance Evaluation of an S-POSS Based PBI Electrolyte for High Temperature PEM Fuel Cell Applications
Authors: Das Susanta K. , Berry K. J.
Published: November 2016

In this paper, using patented nano-additive based polymer synthesis technology, a novel approach to the design and fabrication of high temperature proton exchange membrane (PEM) has been developed. The presence of sulfonated octaphenyl POSS (S-POSS) in a PBI-PA (polybenzimidazole-phosphoric acid) membrane results in a 40–50% increase in conductivity at 120–200$deg relative to non-sulfonated silica or POSS control fillers at comparable weight percent filler loadings and PBI molecular masses, and also relative to unfilled PBI-PA membranes. In addition, the presence of S-POSS and silica both result in physical reinforcement of the membrane and increased its modulus and mechanical integrity, but only S-POSS offers the benefits of both increased conductivity and increased modulus. Isophthalic acid and 3,3’-diaminobenzidine (DAB) were polymerized in the presence of polyphosphoric acid (PPA) and S-POSS nanoadditive, and the degree of polymerization was monitored by viscosity and torque change measurements. Molecular mass was determined by inherent viscosity measurements of samples removed from the reaction solution. Membranes were prepared by casting the reaction solution and allowing PPA to hydrolyze to PA under ambient conditions. The membranes were characterized for acid content, in-plane conductivity, tensile modulus and shear modulus, and were roll-milled to achieve the desired thickness for membrane electrode assembly (MEA) fabrication.
Non Flow-Through (NFT), Advanced Product Water Removal (APWR), Low Temperature PEM Fuel Cell With Reduced Balance of Plant for Air-Independent Applications
Authors: LaGrange Jay W. , Smith William F.
Published: November 2016

Recent developments in applications such as Pulsed Power, Space, High Altitude Long Endurance (HALE) aircraft and underwater vehicles have created interest in the application of air-independent fuel cells. The attraction for such systems has been the potential for high performance, long life and high energy density allowing for extended mission operations and simple recharge.

A limitation of such systems, to date, has been the relatively complicated balance of plant required for system operation. This typically requires circulation of one or both reactants to remove product water and distribute reactants. These parasitic systems can reduce the overall efficiency and maintainability of the system, create noise and inhibit or prevent certain missions.

Under the sponsorship of the NASA Glenn Research Center Infinity has developed a Non Flow-Through (NFT) Advanced Product Water Removal (APWR) Proton Exchange Membrane Fuel Cell system. The design eliminates the need to actively circulate reactants and can remove water directly from the reaction site within the cell. This low temperature, compact, lightweight technology projects to a system with the operational simplicity and reliability of a battery but with the performance and recharge capability of fuel cells.

This paper will report on the operational characteristics, performance and benefits of Infinity’s APWR fuel cell. An update on development status and recent testing results will be included.
Real-Time Model of a Fuel Manifold in a Solid Oxide Fuel Cell Stack for Fuel Flexibility Studies
Authors: Tucker David , Zaccaria Valentina , Harun Nor Farida
Published: November 2016

Solid Oxide Fuel Cells (SOFCs) are considered fairly flexible in terms of employed fuel since the high operating temperature allows direct internal conversion of hydrocarbons to hydrogen. When fed with coal-derived syngas, significant fluctuations in the fuel composition are expected; hence, the study of the fuel cell response to sudden composition changes is a problem of interest. The fuel manifold is an essential component of a fuel cell system, since every change in the fuel upstream is delayed through the manifold before impacting the fuel cell performance. An accurate model of the manifold is extremely important to determine how the fuel cell can handle fuel composition variations.

In this work, a real-time model of a fuel manifold for a SOFC stack was developed. The model included a fuel valve, a pipe, and a distribution system of the fuel in the channels, and it was incorporated in a previously developed real-time, distributed model of a SOFC. Darcy equation for pressure losses and ideal gas law for the fuel properties were employed, ensuring the required computational time of 30 ms could be met. A parametric analysis was performed varying the geometry and the fuel conditions (composition, mass flow rate, temperature, and pressure) in order to ensure the validity of the assumptions in the operative range of interest.

The residence time in the manifold volume was evaluated with the model, and a composition change was applied to the inlet fuel in order to analyze the time delay. These aspects appeared to be very critical in a view of real-time control of the fuel cell dynamics.
Role of Catalyst in Solid Biomass Gasification
Authors: Burra K. G. , Gupta A. K.
Published: November 2016

Energy recovery from biomass is of pinnacle importance for renewable and sustainable energy development. Gasification techniques offer efficient and effective transformation of solid biomass into gas/liquid fuels and value added materials. This technique offers clean energy production with improved efficiency compared to other transformation techniques. Catalysts offer improved reaction efficiency and product yield. However, a robust catalyst for efficient biomass conversion to fuel gases requires close examination. Transitional metals, being inert compared to alkali metals, have shown good catalytic activity in reformation reactions, such as, high temperature and low temperature water-gas shift reactions in ammonia plants with good heat conductivity and catalytic activity. In this study catalytic conversion of pine wood chips using dry (CO2) gasification is investigated. The catalytic effects of CuO/Al2O3-SiO2 (made by wetness impregnation) on the rate of gasification, along with the gaseous species evolved during the gasification at different temperatures (700°C to 900°C) using CO2 are investigated in a semi-batch type reactor. The H2/CO ratio in the syngas and the temporal evolution of various gases evolved, their total yield, and the energy yield are quantified from the analysis of gases evolved. The results reveal significant enhancement in H2 yield and production rate along with selective dry reformation of CH4, while the effect on CO yields were unaffected. Improved yields of H2 and CH4 but no change in CO suggest the catalytic activity of CuO in enhancing the formation of high molecular weight hydrocarbons.
Thermal Performance and Stress Monitoring of Power Boiler
Authors: Taler Jan , Węglowski Bohdan , Sobota Tomasz , Taler Dawid , Trojan Marcin , Dzierwa Piotr , Jaremkiewicz Magdalena , Pilarczyk Marcin
Published: November 2016

The paper presents a method for determination of thermo-flow parameters for steam boilers. This method allows to perform the calculations of the boiler furnace chamber and heat flow rates absorbed by superheater stages. These parameters are important for monitoring the performance of the power unit. Knowledge of these parameters allows determining the degree of the furnace chamber slagging. The calculation can be performed in online mode and use to monitoring of steam boiler. The presented method allows to the operation of steam boiler with high efficiency.
Design and Performance of a Small Hybrid Solar Collector
Authors: Zielinski Alex , Dillon Heather , Baldwin Becca , Forinash Caitlin , Zada Kyle , Stillinger Chad , Dieter Keaton
Published: November 2016

A hybrid solar water collection system was designed to determine the benefits of combining a flat plate collector with evacuated tubes. The system used a flat plate collector with five evacuated tubes to maximize solar absorption from direct and diffuse solar radiation. The performance of the hybrid collector was evaluated by collecting data while the system operated at a range of flow rates and solar insolation levels over several months. The maximum change in temperature was 48.6°C with a flow rate of 0.0063 kg/s. Analysis of the data quantified the maximum change in temperature and a range of maximum system efficiency between 40–45%.
Computational Fluid Dynamics Modelling for the Prediction of NOx in a Waste Gas Boiler
Authors: Blackmore Adam , Woloshyn Jennifer , Baker Duane
Published: November 2016

Recent results from CFD modelling of a waste gas boiler (WGB) to predict Nitrogen Oxides (NOx) emissions are presented. A verification / validation discussion is highlighted comparing the computational fluid dynamics (CFD) modelling with field measurements of NOx and flame characteristics. Challenges associated with the accurate prediction of NOx emissions are discussed along with the ability of CFD to accurately model emissions from an industrial scale WGB.
Operational Reliability and Modernization of Refineries in Mexico: How?, Why? and Where?
Authors: Ruiz Flores Luis Ivan , Castellanos Bustamante Rafael , Calderon Guizar Jorge Guillermo
Published: November 2016

This article presents the “Why?” to modernize the electrical systems in the six refineries in Mexico, derived that since 1979 there has not built a new refinery, and the primary electrical equipment at each refinery to process fuel requires of imperative upgrading. It also presents the “How?” partial changes are being implemented in some refineries such as replacing electrical equipment in the short-term and implementation of new distribution systems in the long term. Also, it comes in “Where?” They are making the necessary changes including the integration of new electrical generators to supply the energy deficit. The state of the art in operational reliability today in Mexico is presented as part of a projection to fulfill the following objectives: a) optimize the security of personnel integration of new electrical equipment meeting international standards, b) Contribute the least damage to the primary electrical equipment in each refinery and c) allow tangible service continuity in the process of oil production. The result of this work is to show conditions change in Mexican refineries with an electric approach and culture in the safety of staff and the facilities themselves.