bluuebunny/crossref_metadata_2025 huggingface dataset:
Political‐Economy Analysis, Aid Effectiveness and the Art of Development Management
Authors: Copestake James , Williams Richard
Published: December 2013

Recognising that aid effectiveness critically depends upon the quality of host‐country institutions and policies, international aid agencies have sought to inform their activities through more systematic political‐economy analysis (PEA). In this article, three analytical frameworks for PEA are compared, contrasted and critically appraised in the light of reflections by PEA practitioners and recent theoretical debate about development management. The article finds that the potential of PEA to improve development effectiveness depends on how far it addresses the micro as well as macro politics of aid and permits a finer‐grained engagement between analysis and action. This requires more reflexivity on the part of those who commission and produce PEA, and further movement from intervention to interaction modalities for aid delivery.
Control of Reaction Pathways for Rapid Synthesis of Negative Thermal Expansion Ceramic Zr2P2WO12 with Uniform Microstructure
Authors: Liu Xiansheng , Wang Junqiao , Fan Chunzhen , Shang Rui , Cheng Fuxing , Yuan Baohe , Song Wenbo , Chen Yongguang , Liang Erjun , Chao Mingju
Published: December 2013

The reaction pathways to synthesize Zr2P2WO12 (ZPW) from ZrO2, WO3, and P2O5 are studied. It is found that there exist two different reaction pathways: One is direct reaction, while another is through an intermediate phase ZrP2O7. The reaction pathways are determined by drying and sintering temperatures. By controlling the reaction pathways, namely avoiding the intermediate phase, negative thermal expansion ceramic ZPW can be synthesized within several minutes. Besides, as‐synthesized specimens possess much smaller and uniform grain size distribution than those synthesized by conventional methods. The investigation paves a way toward rapid and environmental friendly synthesis of ZPW and related compounds.
Prehospital Factors Determining Regional Variation in Thrombolytic Therapy in Acute Ischemic Stroke
Authors: Lahr Maarten M. H. , Vroomen Patrick C. A. J. , Luijckx Gert-Jan , van der Zee Durk-Jouke , de Vos Ronald , Buskens Erik
Published: December 2013

Background

Treatment rates with intravenous tissue plasminogen activator vary by region, which can be partially explained by organizational models of stroke care. A recent study demonstrated that prehospital factors determine a higher thrombolysis rate in a centralized vs. decentralized model in the north of the Netherlands.

Aim

To investigate prehospital factors that may explain variation in thrombolytic therapy between a centralized and a decentralized model.

Methods

A consecutive case observational study was conducted in the north of the Netherlands comparing patients arriving within 4·5 h in a centralized vs. decentralized stroke care model. Factors investigated were transportation mode, prehospital diagnostic accuracy, and preferential referral of thrombolysis candidates. Potential confounders were adjusted using logistic regression analysis.

Results

A total of 172 and 299 arriving within 4·5 h were enrolled in centralized and decentralized settings, respectively. The rate of transportation by emergency medical services was greater in the centralized model (adjusted odds ratio 3·11; 95% confidence interval, 1·59–6·06). Also, more misdiagnoses of stroke occurred in the central model ( P = 0·05). In postal code areas with and without potential preferential referral of thrombolysis candidates due to overlapping catchment areas, the odds of hospital arrival within 4·5 h in the central vs. decentral model were 2·15 (95% confidence interval, 1·39–3·32) and 1·44 (95% confidence interval, 1·04–2·00), respectively.

Conclusions

These results suggest that the larger proportion of patients arriving within 4·5 h in the centralized model might be related to a lower threshold to use emergency services to transport stroke patients and partly to preferential referral of thrombolysis candidates.
Oral impacts on daily performances and recent use of dental services in schoolchildren
Authors: Monsantofils Monica , Bernabé Eduardo
Published: December 2013

Objectives

To explore whether oral impacts on daily performances are related to recent use of dental services among children and whether oral impacts on specific daily performances are more strongly related to recent use of dental services.

Methods

Data from a cross‐sectional survey, including 805 11–12‐year‐old children attending four randomly selected schools in Lima (Peru), were used. The child version of the oral impacts on daily performances (Child‐OIDP) was used to assess prevalence, intensity, and extent of oral impacts. Use of dental services was assessed by self‐reports of last dental visit and reason for the visit. Associations of the prevalence, intensity, and extent of oral impacts with use of dental services were tested in logistic regression models.

Results

Children with oral impacts were 1.99 (95% CI: 1.17–3.37) times more likely to have used dental services recently than their counterparts. The intensity and extent of oral impacts were linearly associated with children's use of dental services. Difficulties in eating were the only type of oral impacts on daily performances associated with use of dental services, independent of children's demographic characteristics, and impacts on other performances.

Conclusion

Oral impacts on daily performances were related to recent use of dental services among these schoolchildren.
Structural and Mechanical Properties of Nanoporous Silica
Authors: Rimsza J. M. , Du Jincheng
Published: December 2013

Nanoporous silica systems with porosity between 30% and 70% were developed using two Molecular Dynamics (MD) simulation protocols to obtain structures with dissimilar pore morphologies. Short‐ and medium‐range structural characteristics including bond angle distributions and pair distribution functions were analyzed and found to be consistent with experimental results. Surface area to volume ratio and pore microstructures were characterized and compared with experimental observations. Mechanical properties including elastic, shear, and bulk moduli of these nanoporous silica systems were calculated and their change as a function of porosity was compared with experimental data and theoretical models. It was found that the elastic modulus of porous silica with 50% porosity is 5–14 GPa which is consistent with experimental results. The elastic moduli–porosity relationship was fitted by exponential and power functions, and analysis of coefficients was performed to obtain microstructure characteristics of the simulated nanoporous silica structures. This works confirms that two distinct nanoporous silica microstructures are generated with MD simulations which result in variations in mechanical properties and highlight the importance of selecting a nanoporous silica simulation method which approximates experimental systems.
Synthesis and Characterization of Ethylene‐Bridged Copolycarbosilazane as Precursors for Silicon Carbonitride Ceramics
Authors: Su Dong , Li Yali , Hou Feng , Yan Xiao
Published: December 2013

An ethylene‐bridged copolycarbosilazane precursor of copolysilylethylenediamine (co‐PSDA) is synthesized by polycondensation of ethylenediamine with the mixture of vinylmethyldichlorosilane and methyldichlorosilane in the presence of triethylamine as acid absorbing agent. Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR, 1H NMR and 13C NMR) spectral analysis of the as‐synthesized co‐PSDA suggests a structure of ethylene‐bridged polycarbosilazane having –Si–N–C–C–N– as backbone chain with –CH=CH2, –H and –CH3 attached to Si as side groups. Co‐PSDA can be cross‐linked at 80°C using 2, 2‐azobisisobutyronitrile as initiator through the polyaddition of the vinyl group and dehydrogenation/deamination of Si–H and N–H. Then the cross‐linked co‐PSDA precursor is pyrolyzed at 1000°C in argon, giving out amorphous silicon carbon nitride (SiCN) ceramics with a high ceramic yield of 76 wt%. The obtained SiCN ceramics consist of nitrogen‐rich silicon sites of SiN4 as predominant component and some SiCN3 sites, which should arise from the breaking of N–C bonds below 600°C and the formation of active N–Si bonds.
Co‐researching with People who Have Intellectual Disabilities: Insights From a National Survey
Authors: O'Brien Patricia , McConkey Roy , García‐Iriarte Edurne
Published: December 2013

Background

Inclusive research with people with intellectual disabilities is growing internationally but with few studies examining its feasibility.

Methods

In undertaking a national study exploring what life was like in Ireland for people with intellectual disabilities, a community of practice was developed involving a core group of co‐researchers: five people with intellectual disabilities, four university researchers and three service support staff. An additional cadre of 15 co‐researchers with intellectual disabilities was recruited to undertake data gathering and analysis with 23 focus groups involving 168 participants. The research experience was documented through oral feedback, progress reports, minutes and a project review.

Results and conclusions

The key learning is documented arising from the setting up of an inclusive advisory group and implementation of each of six research steps. The study demonstrates feasibility and the added value of university co‐researchers recruiting and developing skills together with co‐researchers with intellectual disabilities. Topics for further research and development are identified.

Accessible Abstract

This paper tells you about how people with intellectual disabilities worked with a group of university researchers. Both groups were called co‐researchers and together they ran 23 focus groups across Ireland. People with intellectual disabilities talked about their lives and what could make them better. They said they needed to have a good place to live; a job; enough money; relationships; and acceptance as respected citizens.

The university co‐researchers wrote about what it was like doing research together and how people with intellectual disabilities joined the advisory group; decided on the questions; ran focus groups; and presented findings.

Together they grew into a community of researchers where the university co‐researchers shared their research skills and people with intellectual disabilities shared what it was like living with a disability. They both saw great value in working together and plan to work more to make this type of research happen.
Molecular genetic diversity and genetic structure of Vietnamese indigenous pig populations
Authors: Pham L.D. , Do D.N. , Nam L.Q. , Van Ba N. , Minh L.T.A. , Hoan T.X. , Cuong V.C. , Kadarmideen H.N.
Published: December 2013

The study characterized genetic diversity and genetic structure of five indigenous pig populations (Ha Lang, Muong Te, Mong Cai, Lung and Lung Pu), two wild pig populations (Vietnamese and Thai wild pigs) and an exotic pig breed (Yorkshire) using FAO/ISAG recommended 16 microsatellite markers in 236 samples. All estimated loci were very polymorphic indicated by high values of polymorphism information content (from 0.76 in S0225 to 0.92 in Sw2410). Indigenous populations had very high level of genetic diversity (mean He = 0.75); of all indigenous breeds, Lung Pu showed highest mean number of alleles (MNA = 10.1), gene diversity (He = 0.82), allele richness (5.33) and number of private alleles (10). Thirteen percentage of the total genetic variation observed was due to differences among populations. The neighbour‐joining dendrogram obtained from Nei's standard genetic distance differentiated eight populations into four groups including Yorkshire, two wild populations, Mong Cai population and a group of four other indigenous populations. The Bayesian clustering with the admixture model implemented in Structure 2.1 indicated seven possible homogenous clusters among eight populations. From 79% (Ha Lang) to 98% (Mong Cai). individuals in indigenous pigs were assigned to their own populations. The results confirmed high level of genetic diversity and shed a new light on genetic structure of Vietnam indigenous pig populations.
Sex‐specific life history responses to nymphal diet quality and immune status in a field cricket
Authors: Kelly C. D. , Neyer A. A. , Gress B. E.
Published: December 2013

Individual fitness is expected to benefit from earlier maturation at a larger body size and higher body condition. However, poor nutritional quality or high prevalence of disease make this difficult because individuals either cannot acquire sufficient resources or must divert resources to other fitness‐related traits such as immunity. Under such conditions, individuals are expected to mature later at a smaller body size and in poorer body condition. Moreover, the juvenile environment can also produce longer‐term effects on adult fitness by causing shifts in resource allocation strategies that could alter investment in immune function and affect adult lifespan. We manipulated diet quality and immune status of juvenile Texas field crickets,Gryllus texensis, to investigate how poor developmental conditions affect sex‐specific investment in fitness‐related traits. As predicted, a poor juvenile diet was related to smaller mass and body size at eclosion in both sexes. However, our results also reveal sexually dimorphic responses to different facets of the rearing environment: female life history decisions are affected more by diet quality, whereas males are affected more by immune status. We suggest that females respond to decreased nutritional income because this threatens their ability to achieve a large adult body size, whereas male fitness is more dependent on reaching adulthood and so they invest in immunity and survival to eclosion.
National survey of Australian paediatricians' approach to infant crying
Authors: Rimer Romi , Hiscock Harriet
Published: December 2013

Aim

Persistent crying in infancy (i.e. crying that lasts for more than 3 h a day for more than 3 days per week for at least 3 weeks) is widespread. Although there is no gold standard approach to its management, guidelines exist with common management principles. This study aims to document how Australian general paediatricians (i) assess and manage persistent crying compared with published guidelines; (ii) screen for and manage associated post‐natal depression; and (iii) rate their training in this area.

Methods

Online survey were administered to all 394 members of the Australian Paediatric Research Network in November 2011 to February 2012. Members are predominantly general paediatricians.

Results

A total of 168 paediatricians (45%) responded. The majority (n = 96 (69%)) take one session to assess infant crying and at least two sessions to manage it (n = 106 (79%)). Specific approaches are not always evidence based (e.g. use of antacids/simethicone by 8%) and do not follow available guidelines. Most paediatricians routinely asked about maternal (n = 120 (88%)) but not paternal (n = 51 (33%)) mental health. Paediatricians typically received training around this issue before rather than after gaining formal paediatric qualifications (61% vs. 37%, respectively) and rate their training as satisfactory (67%). Despite this, only 39% feel very confident in managing infant crying.

Conclusion

The lack of a gold standard approach to managing persistent infant crying has likely contributed to a lack of uniform care among Australian general paediatricians. Given that most paediatricians do not feel very confident in dealing with this problem, there is a scope for further training supported by evidence‐based guidelines.
Detection and Molecular Variability of Turnip mosaic virus (TuMV) in Shaanxi, China
Authors: Zhao Lei , Feng Chaohong , Hao Xingan , Wang Renrui , Hu Lingyun , Wang Qiaochun , Wu Yunfeng
Published: December 2013

Turnip mosaic virus (TuMV) is one of the most devastating threats to oilseed rape by causing serious crop losses. A total of 86 leaf samples of oilseed rape from eight different locations in Shaanxi, China, were tested by RT‐PCR for TuMV; the results revealed an infection level of 43% by TuMV. The complete coat protein (CP) gene of 32 TuMV isolates was cloned and sequenced. Analysis of the CP gene with sequences from the database allowed the genetic classification of 170 TuMV isolates or sequences. Four genetic clusters were obtained: MB (mostly Brassica isolates), MR (mostly Radish isolates), IBR (mostly Intermediate between Brassica and Radish clusters) and OBR (mostly outside Brassica and Radish clusters). All subgroups were slightly related to the hosts, but unrelated to geographical origins. Most of Shaanxi TuMV isolates were on separate branches, compared with the 138 known isolates originating from other parts of the world. Our results help provide a better understanding of the genetic diversity of TuMV isolates infecting oilseed rape in Shaanxi, China.
Species delimitation and phylogeny in the genus Nasutitermes (Termitidae: Nasutitermitinae) in French Guiana
Authors: Roy Virginie , Constantino Reginaldo , Chassany Vincent , Giusti‐Miller Stephanie , Diouf Michel , Mora Philippe , Harry Myriam
Published: December 2013

Species delimitation and identification can be arduous for taxa whose morphologic characters are easily confused, which can hamper global biodiversity assessments and pest species management. Exploratory methods of species delimitation that use DNA sequence as their primary information source to establish group membership and estimate putative species boundaries are useful approaches, complementary to traditional taxonomy. Termites of the genus Nasutitermes make interesting models for the application of such methods. They are dominant in Neotropical primary forests but also represent major agricultural and structural pests. Despite the prevalence, pivotal ecological role and economical impact of this group, the taxonomy of Nasutitermes species mainly depends on unreliable characters of soldier external morphology. Here, we generated robust species hypotheses for 79 Nasutitermes colonies sampled throughout French Guiana without any a priori knowledge of species affiliation. Sequence analysis of the mitochondrial cytochrome oxidase II gene was coupled with exploratory species‐delimitation tools, using the automatic barcode gap discovery method (ABGD) and a generalized mixed Yule‐coalescent model (GMYC) to propose primary species hypotheses (PSHs). PSHs were revaluated using phylogenetic analyses of two more loci (mitochondrial 16S rDNA and nuclear internal transcribed spacer 2) leading to 16 retained secondary species hypotheses (RSSH). Seven RSSHs, represented by 44/79 of the sampled colonies, were morphologically affiliated to species recognized as pests in the Neotropics, where they represent a real invasive pest potential in the context of growing ecosystem anthropization. Multigenic phylogenies based on combined alignments (1426–1784 bp) were also reconstructed to identify ancestral ecological niches and major‐pest lineages, revealing that Guyanese pest species do not form monophyletic groups.
Transcendental experiences during meditation practice
Authors: Travis Frederick
Published: December 2013

This article explores transcendental experiences during meditation practice and the integration of transcendental experiences and the unfolding of higher states of consciousness with waking, dreaming, and sleeping. The subject/object relationship during transcendental experiences is characterized by the absence of time, space, and body sense—the framework that gives meaning to waking experiences. Physiologically, transcendental experiences during Transcendental Meditation practice are marked by slow inhalation, along with autonomic orientation at the onset of breath changes and heightened α1 (8–10 Hz) frontal coherence. The integration of transcendental experiences with waking, dreaming, and sleeping is also marked by distinct subjective and objective markers. This integrated state, called Cosmic Consciousness in the Vedic tradition, is subjectively marked by inner self‐awareness coexisting with waking, sleeping, and dreaming. Physiologically, Cosmic Consciousness is marked by the coexistence of α1 electroencephalography (EEG) with delta EEG during deep sleep, and higher brain integration, greater emotional stability, and decreased anxiety during challenging tasks. Transcendental experiences may be the engine that fosters higher human development.
Analysis of the mucosal immune responses induced by single and trickle infections with the bovine abomasal nematode Ostertagia ostertagi
Authors: Mihi B. , van Meulder F. , Vancoppernolle S. , Rinaldi M. , Chiers K. , van den Broeck W. , Goddeeris B. M. , Vercruysse J. , Claerebout E. , Geldhof P.
Published: December 2013

The purpose of this study was to provide more information on the kinetics of the immunological changes occurring in the abomasal mucosa after single and trickle infections with the bovine parasite Ostertagia ostertagi. The time course analysis of gene expression revealed that the major changes coincided with the emergence of adult worms from the gastric glands. These changes consisted of a simultaneous upregulation of Th1‐ and Th2‐type cytokines. In addition, a single O. ostertagi infection elicited an upregulation of the epithelial‐derived cytokine IL33, while TSLP expression levels were not impacted. Apart from the massive increase in inflammatory cytokines IL6, IL17 and IL21, O. ostertagi infection also elicited an upregulation of the immunosuppressors TGFB, IL10 and ARG1, as well as NK and γδ‐T cell markers. Furthermore, the cytotoxic factors granulysin, perforin and granzyme B were upregulated following an O. ostertagi infection. Analysis of cytokine transcript levels in animals receiving trickle infections for 60 days showed a similar trend as observed following a single infection except for IL33, IL6, GATA‐3, TBX21 and NCR1, which were no longer upregulated after trickle infections. Finally, the long trickle infections were associated with mucosal eosinophilia and mastocytosis.
Global governance of training standards in an outsourced labor force: The training double bind in seafarer license and certification assessments
Authors: Bloor Michael , Sampson Helen , Gekara Victor
Published: December 2013

The shipping industry is among the most globalized of all industries and is characterized by complex modular supply chains, including a largely outsourced labor force of “just‐in‐time” casualized workers from developing countries and the transitionalEastEuropean states. Despite long‐standing efforts by international bodies to standardize and regulate the education and training of seafarers, variations in practices and standards persist. Employers exercise contradictory influences on education and training providers, on the one hand demanding the urgent provision of more recruits (encouraging corner‐cutting), and on the other complaining about the poor quality of recruits received (urging crackdowns on poor quality providers and more rigorous examinations) – the training double bind. This paper reflects on these issues through the study of the problematic use of computerized assessments in seafarer examinations, drawing upon findings from a study involving research in six different case study countries providing maritime labor and interviews with stakeholders.
Optimization, Numerical, and Experimental Study of a Propeller Pump as Turbine
Authors: Derakhshan Shahram , Kasaeian Nemat
Published: December 2013

Micro hydropower station is one of the clean choices for offgrid points with available hydropotential. The challenging in this type of energy production is the high capital cost of the installed capacity that is worse for low-head micro hydropower stations. Turbine price is the main problem for this type of energy production. In this research, a simple machine has been introduced instead of conventional propeller turbines. The key is using an axial pump as a propeller turbine. In the present research, a propeller pump was simulated as a turbine by numerical methods. Computational fluid dynamics (CFD) was adopted in the direct and reverse modes performance prediction of a single propeller pump. To give a more accurate CFD result, all domains within the machine control volume were modeled and hexahedral structured mesh was generated during CFD simulation. Complete performance curves of its pump and turbine modes were acquired. For verification of the numerical results, the machine has been tested in an established test ring. The results showed that a propeller pump could be easily run as a low-head turbine. In the next, the goal was to optimize the geometry of the blades of axial turbine runner which leads to maximum hydraulic efficiency by changing the design parameters of camber line in five sections of a blade. The efficiency of the initial geometry was improved by various objective functions and optimized geometry was obtained by genetic algorithm and artificial neural network to find the best efficiency of the turbine. The results showed that the efficiency is improved by more than 14%. Indeed the geometry has better performance in cavitation.
Comparison of Open Chain and Closed Chain Planar Two Degree of Freedom Manipulator for Positional Error
Authors: Jawale H. P. , Thorat H. T.
Published: December 2013

Open chain and closed chain manipulators are designed for specific objectives. Closed chain five bar manipulator is possible to be configured as a substitute to an open chain two degree of freedom (DoF) manipulator. Positional accuracy is one of the factors for performance evaluation, characterizing suitability of a configuration over the other. Present paper attempts comparative analysis of positional inaccuracy of closed chain five bar manipulator and serial chain configuration. Both manipulators are modeled for positional deviations under identical specifications considering randomness due to joint clearances and backlash in drive. The maximum positional inaccuracy is expressed in terms of dimensionless number as error index (EI) to estimate the comparative behavior of the manipulators. Positional error under influence of backlash and clearances is quantified. Comparison of two configurations is presented and conditional superiority of a configuration over the other is commented using geometric approach.
Sustainable Ground Transportation: Technologies, Challenges and Opportunities
Authors: Agarwal Ramesh
Published: December 2013

Currently there are nearly 750 million ground vehicles in service worldwide. They are responsible for 50% of petroleum (oil) consumption and 60% of all greenhouse gas (GHG) emissions worldwide. The number of vehicles is forecasted to double by 2050. Therefore the environmental issues such as noise, emissions and fuel burn have become important for energy and environmental sustainability. This paper provides an overview of specific energy and environmental issues related to ground transportation. The technologies related to reduction in energy requirements such as reducing the vehicle mass by using the high strength low weight materials and reducing the viscous drag by active flow control and smoothing the operational profile, and reducing the contact friction by special tire materials are discussed along with the portable energy sources for reducing the GHG emissions such as low carbon fuels (biofuels), Lithium-ion batteries with high energy density and stability, and fuel cells. The technological challenges and opportunities for innovations are discussed.
Wind Solar Hybrid Power System Modeling and Analysis
Authors: Vijayaraghavan Krishna , Tyagi Himanshu , Randhawa Shahzada , Singh Manpreet
Published: December 2013

India has always been victim of power failures or blackouts and the recent July 2012 countrywide blackout is a perfect example for it. It is expected that due to the widening gap between supply and demand, such instances of power failure would occur more regularly in future. Such blackouts are also be foreseen in other parts of the world. The electricity grids in many countries are highly centralized and are mostly dependent on fossil-fuel based energy sources (coal, oil, natural gas etc). Due to the rapid rise in the living standards of developing countries such as India and China, there is an increase in demand for electricity for running various appliances, as well as for heating and air-conditioning equipment. Such an increased in demand places tremendous strain on ailing centralized grid burning fossil fuel. The use of renewable energy sources (such as solar and wind) could potentially allow large amount of demand to be met though alternative means and offset the demand on the grid.

The advancement in technology has encouraged the implementation of renewable resources especially solar and wind. Hybrid power systems (HPS) that consist of these resources can significantly lower storage requirements. Furthermore, besides being cost-efficient, it is coherent to the weather conditions since solar and wind complement each other well. For highly efficient hybrid power systems to be developed, a significant degree of research must be applied to further their development. This includes tasks such as modeling these systems and applying proficient control algorithms to maximize efficiency. This paper focuses on simulation of an HPS consisting of a photovoltaic (PV) module, wind turbine (WT), and a lead acid battery through MATLAB/SIMULINK software. Moreover, a control algorithm is proposed, which leads to an efficient and autonomous operation of the HPS, along with maximizing power output from PV module and WT. The model and control system were tested using sample hourly solar radiation, temperature, and wind speed data to generate the power output from the PV module and WT, which was then processed through the proposed algorithm, to power a sample hourly load profile. The results indicate that a simple HPS can meet the type of load demand provided in an efficient and effective manner.
Investigating the Energy Content and Storability of Torrefied Corn Stover Based on Varying Reaction Time and Temperature
Authors: Gerometta Christina , Gent Stephen P. , Twedt Michael P.
Published: December 2013

This study investigates the effects of torrefaction temperature and time on the energy content and storage stability of bio-char derived from corn stover feedstock. The batch torrefaction system in this study uses 91.4 cm × 25.4 cm diameter reactors with electrical heating elements to torrefy large samples of corn stover. The reactor is typically loaded with 0.5 kg samples of chopped corn stover (stalks, leaves, and cobs) with particle surface areas ranging from 0.5–2.4 cm2. The operating temperatures range from 230–340 degrees C, while the operating times range from 30–60 minutes. After each reaction trial, the energy content of the bio-char is quantified using the heat of combustion value obtained from bomb calorimeter tests on each of the samples. Values from these tests are compared to previous research to investigate the feasibility of larger-scale torrefaction reactions with mixed component stover. Temperature and time profiles are obtained from an Arduino output to investigate temperature behaviors during the reaction. The temperature and energy content can provide the basis for defining the phases of torrefaction.

The long-term goal of this research is to assess the viability of producing a high energy, storable bio-char as well as a usable biogas from the torrefaction process of corn stover feedstocks. Since compounds within the corn stover have different reaction rates, a composition analysis of samples at various stages in torrefaction will indirectly provide information on the usability of the biogas and behaviors of organic compounds in the reaction. Therefore, the torrefaction conditions must be specified before moving forward.
Investigation of Hydrodynamics and Heat Transfer Effects due to Light Guides in a Column Photobioreactor
Authors: Gerdes Caitlin , Suess Taylor N. , Anderson Gary A. , Gent Stephen P.
Published: December 2013

Proper light penetration is an essential design consideration for effective algae growth in column photobioreactors. This research focuses on the placement of light guides within a photobioreactor (PBR), and the effect they have on heat transfer, mass transfer, bubble and fluid flow patterns, and mixing. Studies have been done on a rectangular column photobioreactor (34.29 cm long × 15.25 cm wide × 34.29 cm tall) with two light panels along the front and back of the PBR. A bubble sparger is placed along the center of the bottom length of the PBR with both height and width of 1.27 cm and a length of 33.02 cm. Different configurations and numbers of light guides (1.27 cm diameter) running horizontally from the front to the back of the PBR are modeled using the Computational Fluid Dynamics (CFD) software Star-CCM+. It is hypothesized that the addition of light guides will change the flow pattern but not adversely affect the heat or mass transfer of the carbon dioxide bubbles within the PBR. Potential concerns of light guide placement include inhibiting the flow of the carbon dioxide bubbles or creating regions of high temperature, which could potentially kill the algae. Benefits of light guides include increased light penetration and photosynthesis within the PBR. Five different light guide setups are tested with the carbon dioxide bubbles and water modeled as a turbulent multiphase gas-liquid mixture. The near wall standard k-epsilon two layer turbulence model was used, as it takes into account the viscosity influences between the liquid and gaseous phases. Eight different bubble volumetric flow rates are simulated. The bubble flow patterns, temperature distribution, Nusselt number, Reynolds number, and velocity are all analyzed. The results indicate square arrays of light guides give the most desirable velocity distribution, with less area of zero velocity compared to the staggered light guide setup. Temperature distribution is generally even for all configurations of light guides.
Fluidized Bed Kinetics for Hydrogen Production Through Steam Iron Oxidation
Authors: Al-Raqom Fotouh , Klausner James F.
Published: December 2013

Kinetic analysis is essential for chemical reactor modeling. This study proposes a methodology to use available kinetic analysis methodologies, including conventional (modelistic) graphical representation, isoconversional (model free), models based on first principles and reduced time scale analysis (Sharp and Hancock procedure) to predict the kinetics of an investigated reaction. Even though these methods have some limitations, a methodology comprised of combining their results can help in determining the kinetic parameters for reaction. The isoconversional approach can be used to determine the activation energy without the need of using a reaction model. The modelistic graphical representation can aid is determining the group (i.e. diffusion, first order, phase boundary or nucleation) to which the reaction generally belongs. The reduced time scale analysis can guide in isolating the reaction kinetics in the early stages of the reaction when the conversion ranges between 0.15 and 0.5. This proposed methodology uses the various methods and applies them to experimental data for high temperature reactions in fluidized bed reactors. Particular attention is given to steam driven iron oxidation kinetics for hydrogen production. When only the modelistic approach is used, the activation energy computed using the selected models varies from 59–183 kJ/mol, depending on the model used. However, by combining the predictive capabilities of various approaches discussed in this study, the activation energy range narrows to 80–147 kJ/mol. It is also shown that the iron oxidation with steam under the studied conditions can be described by a combination of two models. The early stage of the reaction is represented by either a contracting volume or first order model. Later stages of reaction can be described by either a contracting volume, first order or 3-D diffusion model. In addition, when analyzing reaction kinetics using a fundamental approach, it is observed that the fluidized bed oxidation reaction of iron with pure steam can be best represented by a combination of two mechanisms, namely shrinking sphere surface area and diffusion controlled mechanisms and the estimated activation energy is 103 kJ/mol.
Thermal Testing of Organic Fluids for Supercritical Thermal Energy Storage Systems
Authors: Tse Louis A. , Stopin Antoine , Ganapathi Gani B. , Garcia-Garibay Miguel A. , Wirz Richard E.
Published: December 2013

Concentrating solar power (CSP) continues to advance as worldwide interest in renewable energy continues to grow. CSP technologies, including parabolic troughs, power towers, and dish/engines, provide the unique potential for low-cost thermal energy storage that will ensure that renewable energy can become cost-competitive with traditional fossil fuel sources on a large scale and comprise a significant portion of the global energy portfolio.

The challenge is to develop cost-effective thermal energy storage to ensure that renewable energy can become a major part of the national and global energy supply. Storage fluid selection is a critical decision that must fulfill a number of criteria to not only provide long-term reliability, but also to remain cost-competitive in the power generation arena. The state-of-the-art thermal storage design uses a 2-tank molten salt configuration. However, most molten salt mixtures have a relatively high freezing temperature, which poses some system design issues. Additionally, the price of molten salt mixtures is steadily increasing. Current laboratory and industry research efforts have shifted focus to exploration of alternative storage fluids to significantly reduce costs.

In this study, several storage fluid candidates have been selected based on an attractive combination of thermodynamic properties, cost, and availability. In this paper, rapid screening of fluid candidates is reported, and an expanded series of thermal cycling and supercritical characterization experiments have been planned and are being implemented to determine the long-term durability of the fluid candidates over a range of operating temperatures for extended periods of time. Commercial-grade materials were used, and in the case of naphthalene and biphenyl, the testing procedure was carefully controlled to prevent sublimation of the sample. This paper presents the results of a study investigating the thermal stability of several organic fluids. Samples were extracted and chemical analyses such as nuclear magnetic resonance (NMR) and gas chromatography (GC) were conducted to observe degradation behavior and decomposition pathways. The rapid screening phase provided a timely and effective filter of the best-performing fluid candidates for supercritical thermal energy storage.
Near-Critical CO2 Flow Measurement and Visualization
Authors: Kazemifar Farzan , Kyritsis Dimitrios C.
Published: December 2013

Near-critical CO2 flow has been studied because of its potential application in carbon dioxide capture and sequestration, which is one of the proposed solutions for reducing greenhouse gas emission. Near the critical point the thermophysical properties of the fluid undergo abrupt changes that affect the flow structure and characteristics. Pressure drop across a stainless steel tube, 2 ft long with 0.084 in ID, at different inlet conditions and mass flow rates have been measured. The effects of variations of inlet conditions have been studied. The results show extreme sensitivity of pressure drop to inlet conditions especially inlet temperature in the vicinity of the critical point. Also, shadowgraphs have been acquired to study the flow structure qualitatively.
In-Situ Experimental Validation of THERM Finite Element Analysis for a High R-Value Wall Using Vacuum Insulation Panels
Authors: Schiedel Matthew , Cruickshank Cynthia A. , Baldwin Christopher
Published: December 2013

Team Ontario is one of twenty collegiate teams selected to design and build a solar powered, net positive home for the U.S. Department of Energy Solar Decathlon 2013. One aspect of Team Ontario’s competition design entry is a high R-value wall using vacuum insulation panels. This paper details the method used for theoretical evaluation of the high R-value wall, stating all simplifying assumptions made. Theoretical simulations were performed in THERM, a two dimensional finite element heat transfer modelling program. Following a weighted average method used by industry experts, the whole-wall thermal resistance value was calculated. To verify the modelling results, an in-situ experimental validation was conducted. An 8′ × 8′ wall test specimen was built to the specifications of Team Ontario’s wall design. Experimental heat flux and temperature readings were collected from the test specimen in Carleton University’s Vacuum Insulation Test Facility located in Ottawa, Ontario, Canada, with the test specimen exposed to exterior weather elements. The experimental and theoretical results are compared and conclusions drawn to determine the effective thermal resistance of the vacuum insulation panels installed in the wall assembly. Finally the theoretical model is refined based on the previous study and a more accurate whole-wall thermal resistance of Team Ontario’s wall design is determined.
Techno-Economic Analysis of Concentrating Solar Power Plants With Integrated Latent Thermal Storage Systems
Authors: Nithyanandam K. , Pitchumani R.
Published: December 2013

Integrating a thermal energy storage (TES) in a concentrating solar power (CSP) plant allows for continuous operation even during times when solar radiation is not available, thus providing a reliable output to the grid. In the present study, the cost and performance models of an encapsulated phase change material thermocline storage system are integrated with a CSP power tower system model to investigate its dynamic performance. The influence of design parameters of the storage system is studied for different solar multiples of the plant to establish design envelopes that satisfy the U.S. Department of Energy SunShot Initiative requirements, which include a round-trip exergetic efficiency greater than 95% and storage cost less than $15/kWht for a minimum discharge period of 6 hours. From the design windows, optimum designs of the storage system based on minimum LCOE, maximum exergetic efficiency, and maximum capacity factor are reported and compared with the results of two-tank molten salt storage system. Overall, this study presents the first effort to construct a latent thermal energy storage (LTES)-integrated CSP plant model, that can help decision makers in assessing the impact, cost and performance of a latent thermocline energy storage system on power generation from molten salt power tower CSP plant.
Manufacturing Optimization of a Kilowatt Scale Vertical Axis Wind Turbine for Remote Applications
Authors: French Jesse J. , Ressler Corey P. , Weigelt John J.
Published: December 2013

Previous work at the institution has successfully shown that a novel VAWT design can be employed to provide electrical power to remote rural villages in a cost effective manner. The VAWT’s design can effectively utilize the non-laminar, low level winds and survive the increased turbulence present at remote and non-optimal installation locations. Previous efforts have improved the overall aerodynamic characteristics of the turbine and scaled these designs from a 100W to a 1kW scaled turbine. In order to remain a viable and affordable solution for use worldwide by truly rural users, these turbines need to have low manufacturing cost and low maintenance costs. This paper presents the work done by the authors to analyze the main cost contributors, manufacturing methods, techniques, and tooling used to improve productivity in the manufacturing process. Design improvements and construction materials were analyzed to reduce overall weight which leads to cost reduction and overall improvements in manufacturability. The specific improvements explored by the authors include redesigning the arms of the turbine to improve aerodynamic efficiency of the turbine, reducing construction materials to minimum allowable values, and designing manufacturing tooling which will allow for rapid production of large quantities of the turbine. Results are presented from over 4000 hours of in-situ testing of the turbine showing that the manufacturing improvements reduced construction time to 25% of the original design and reduced weight by 25% while maintaining full functionality and high-wind survivability.
Investigating the Humidity Effect on Si/PEDOT:PSS Hybrid Solar Cell and Power Conversion Efficiency Recovery by Re-Deposition of the Hole Transporting Layer
Authors: Lam C. Y. , Shi S. Q. , Lu J. , Chan P. K. L.
Published: December 2013

The degradation of silicon nanostructure / poly(3,4-ethylenedioxylthiophene : poly(styrenesulphonic acid) (SiNS/PEDOT:PSS) hybrid solar cell due to the moisture is investigated with an environmental chamber. The unencapsulated devices were tested under different relative humidity (RH) varied from (15% to 100%). Under different RH, the devices show various degradation trends. After 3hrs of storage under 100% RH, the average device power conversion efficiency (PCE) drops from 6.52% to 1.27%. While the device is stored under 15% RH, the averaged PCE just drop from 6.40% to 5.49% and the device at 60% RH degrades from 5.97% to 3.12%. To understand the cause of the device degradation, we compare the ITO conductivity and apply tunneling electron microscopy (TEM) to study the growth of the silicon dioxide layer on the silicon nanostructures. We confirmed that the major cause of the PCE drop in the current devices are due to the decrease of the PEDOT:PSS conductivity and the increase of the interface resistances. By re-depositing the PEDOT:PSS layer onto the degraded device and recycling the Si (and fresh ITO), we demonstrated that the efficiency of the device can be partially recovered (to fully recovered). The current work not only highlighted the importance of the humidity control in these SiNS/PEDOT:PSS hybrid solar cells, but also identified the major causes of the device degradation. The observation has been re-confirmed by recovering the PCE of the degraded device with a fresh PEDOT:PSS layer and a fresh ITO.
Sulfur Based Thermochemical Energy Storage for Concentrated Solar Power
Authors: Wong Bunsen , Thomey Dennis , Brown Lloyd , Roeb Martin , Buckingham Robert , Sattler Christian
Published: December 2013

A sulfur based thermochemical energy storage cycle for baseload power generation is being developed under the support of US DOE Sunshot program. Solar heat is stored in elemental sulfur via thermal decomposition of sulfuric acid and disproportionation of sulfur dioxide into elemental sulfur and sulfuric acid. Heat energy is recovered upon sulfur combustion. On-sun decomposition of sulfuric acid in a solar furnace has been demonstrated between 650 and 850°C. Near equilibrium conversion was obtained at high temperature but conversion was reduced due to catalyst poisoning at the lower temperatures. Sulfur dioxide disproportionation modeling showed the reaction driving force is maximized at the high system pressure and low system temperature. The effect of system pressure was validated experimentally. However, the disproportionation rate was found to increase with system temperature as a result of increased reaction kinetics. Homogenous iodide catalysts were used to further enhance the degree of disproportionation and the reaction rate. The process steps required to recover the catalyst for reuse have been verified.