bluuebunny/crossref_metadata_2025 huggingface dataset:
The role(s) of accounting and performance measurement systems in contemporary public administration
Authors: Steccolini Ileana , Saliterer Iris , Guthrie James
Published: December 2019

The spate of public sector reforms which have taken place in recent decades has triggered the development of a new body of research around public sector accounting and performance measurement both in public administration as well as in the (public sector) accounting literature. However, studies in accounting and public administration have at times ignored each other, proceeding in parallel. This symposium encourages the adoption of interdisciplinary perspectives in exploring the myriad roles played by accounting and performance measurement systems in contemporary public administration. Emphasizing that accounting and performance measurement systems are socially, politically, culturally constructed and, in turn, are implicated in the creation of organizations, society and political values, this symposium aims to extend the dialogue between accounting and public administration scholars in exploring how accounting, accountability and performance measurement considerations are connected to policy‐making, public services and, more generally, the building and maintenance of modern states and democracies.
Increased Rubisco content in maize mitigates chilling stress and speeds recovery
Authors: Salesse‐Smith Coralie E. , Sharwood Robert E. , Busch Florian A. , Stern David B.
Published: December 2019

Many C4 plants, including maize, perform poorly under chilling conditions. This phenomenon has been linked in part to decreased Rubisco abundance at lower temperatures. An exception to this is chilling‐tolerant Miscanthus, which is able to maintain Rubisco protein content under such conditions. The goal of this study was to investigate whether increasing Rubisco content in maize could improve performance during or following chilling stress. Here, we demonstrate that transgenic lines overexpressing Rubisco large and small subunits and the Rubisco assembly factor RAF1 (RAF1‐LSSS), which have increased Rubisco content and growth under control conditions, maintain increased Rubisco content and growth during chilling stress. RAF1‐LSSS plants exhibited 12% higher CO2 assimilation relative to nontransgenic controls under control growth conditions, and a 17% differential after 2 weeks of chilling stress, although assimilation rates of all genotypes were ~50% lower in chilling conditions. Chlorophyll fluorescence measurements showed RAF1‐LSSS and WT plants had similar rates of photochemical quenching during chilling, suggesting Rubisco may not be the primary limiting factor that leads to poor performance in maize under chilling conditions. In contrast, RAF1‐LSSS had improved photochemical quenching before and after chilling stress, suggesting that increased Rubisco may help plants recover faster from chilling conditions. Relatively increased leaf area, dry weight and plant height observed before chilling in RAF1‐LSSS were also maintained during chilling. Together, these results demonstrate that an increase in Rubisco content allows maize plants to better cope with chilling stress and also improves their subsequent recovery, yet additional modifications are required to engineer chilling tolerance in maize.
Brain morphological and functional features in cognitive subgroups of schizophrenia
Authors: Yasuda Yuka , Okada Naohiro , Nemoto Kiyotaka , Fukunaga Masaki , Yamamori Hidenaga , Ohi Kazutaka , Koshiyama Daisuke , Kudo Noriko , Shiino Tomoko , Morita Susumu , Morita Kentaro , Azechi Hirotsugu , Fujimoto Michiko , Miura Kenichiro , Watanabe Yoshiyuki , Kasai Kiyoto , Hashimoto Ryota
Published: December 2019

Aim

Previous studies have reported different brain morphologies in different cognitive subgroups of patients with schizophrenia. We aimed to examine the brain structures and functional connectivity in these cognitive subgroups of schizophrenia.

Methods

We compared brain structures among healthy controls and cognitively deteriorated and preserved subgroups of patients with schizophrenia according to the decline in IQ. Connectivity analyses between subcortical regions and other brain areas were performed using resting‐state functional magnetic resonance imaging among the groups.

Results

Whole brain and total cortical gray matter, right fusiform gyrus, left pars orbitalis gyrus, right pars triangularis, left superior temporal gyrus and left insula volumes, and bilateral cortical thickness were decreased in the deteriorated group compared to the control and preserved groups. Both schizophrenia subgroups had increased left lateral ventricle, right putamen and left pallidum, and decreased bilateral hippocampus, left precentral gyrus, right rostral middle frontal gyrus, and bilateral superior frontal gyrus volumes compared with controls. Hyperconnectivity between the thalamus and a broad range of brain regions was observed in the deteriorated group compared to connectivity in the control group, and this hyperconnectivity was less evident in the preserved group. We also found hyperconnectivity between the accumbens and the superior and middle frontal gyri in the preserved group compared with connectivity in the deteriorated group.

Conclusion

These findings provide evidence of prominent structural and functional brain abnormalities in deteriorated patients with schizophrenia, suggesting that cognitive subgroups in schizophrenia might be useful biotypes to elucidate brain pathophysiology for new diagnostic and treatment strategies.
Diaper dermatitis prevalence and severity: Global perspective on the impact of caregiver behavior
Authors: Carr Andrew N. , DeWitt Thomas , Cork Michael J. , Eichenfield Lawrence F. , Fölster‐Holst Regina , Hohl Daniel , Lane Alfred T. , Paller Amy , Pickering Larry , Taieb Alain , Cui Tao Y. , Xu Zi G. , Wang Xeumin , Brink Susanna , Niu Yeuqing , Ogle Julie , Odio Mauricio , Gibb Roger D.
Published: December 2019

Objectives

To compare prevalence and severity of diaper dermatitis (DD) in infants and toddlers (babies) across three countries (China, USA, and Germany), including diapered skin measures and caregiver practices.

Methods

A cross‐sectional study of 1791 babies (~600 from each country) was recruited at each clinical site. Based on regional toilet‐training habits, exclusively diaper‐wearing infants were recruited between ages 2‐8 months in China and 2‐18 months in the USA and Germany. DD was measured, as well as skin pH, transepidermal water loss (TEWL), and relative humidity (RH) in the diapered region. Caregiver habits were collected via a questionnaire and included information on hygienic practices.

Results

Diaper dermatitis was highest in the perianal area, followed by the intertriginous, genital, and buttock regions. In general, DD was significantly lower in babies in China, highest in Germany, and intermediate in the USA. This rank ordering of DD by geography was also observed in baby age 2‐8 months. The lower DD observed in China was associated with lower skin pH and TEWL on diapered skin and decreased RH in the diaper. Chinese caregivers had the highest rate of prophylactic topical product usage, the most robust cleaning of the diapered area, lack of cleansing after urine‐only diaper changes, and Chinese infants spent the least time in an overnight diaper.

Conclusions

These data suggest caregiver behaviors including prophylactic use of topical products, thorough cleaning after stooling and reduced time in an overnight diaper are associated with less DD, lower superficial skin pH, and enhanced skin barrier.
Association of short sleep duration and long media use with caries in school children
Authors: Asaka Yukiko , Sekine Michikazu , Yamada Masaaki , Tatsuse Takashi , Sano Masayuki
Published: December 2019

Background

Individual lifestyle factors are associated with dental caries in children. The aim of this study was to investigate comprehensively the association between dental caries in elementary school children and lifestyle factors of the children and their parents.

Methods

Children from five elementary schools in Takaoka city, Toyama Prefecture, Japan (1,699: 848 boys, 851 girls, age range 6–12 years) participated in a survey conducted in March 2016. Questions on socioeconomic status (SES) and lifestyle factors in the children and their parents were included. Children who received treatment for three or more dental caries were defined as having many caries. Logistic regression analysis was performed to evaluate whether these factors were associated with the number of caries.

Results

The percentage of children with many caries (≥3) was 38.4%. In univariate analysis, being in 5th or 6th grade, frequent snacking, short sleep duration, long hours of media use, paternal smoking, and parental skipping of breakfast were significantly associated with many caries. Lack of affluence was marginally significant. In multivariate analysis, the association of short hours of sleep and long hours of media use remained significant. The adjusted odds ratio (OR) for media use of 1–2 h and more than 2 h were 1.79 (95% confidence interval [CI]: 1.30–2.46) and 2.24 (95% CI: 1.61–3.11) respectively. The adjusted OR for less than 8 h of sleep was 1.49 (95% CI: 1.07–2.06).

Conclusions

Long duration of media use and short duration of sleep were associated with dental caries. Establishing a healthy lifestyle is necessary for preventing dental caries in children.
Uncivil Name‐Calling in the U.S. Presidency, 1933–2018
Authors: Coe Kevin , Park‐Ozee Dakota
Published: December 2019

Political incivility in the United States is a growing concern among both citizens and scholars. Prior research focusing on incivility among political elites has largely neglected the presidency, however. Thus, popular claims that Donald Trump is particularly uncivil have not yet been subjected to empirical scrutiny vis‐à‐vis presidential norms. The present study undertakes a large‐scale quantitative content analysis of modern presidential communication to provide insight into one key form of incivility: name‐calling. We find that uncivil name‐calling is generally rare in the presidency, and that three presidents—Harry S. Truman, George H. W. Bush, and especially Donald Trump—are outliers in the frequency with which they employ this form of communication.
Historical institutional child abuse: Activist mobilisation and public inquiries
Authors: Wright Katie , Henry Alasdair
Published: December 2019

The abuse of children in institutional settings is an issue of ongoing social, public, and political concern internationally. While societal responses to historical abuse have been the subject of considerable scholarship in recent years, conceptualisation of the role of activism remains limited. This article aims to advance sociological and interdisciplinary perspectives on nonrecent institutional child abuse through a conceptualisation of activist mobilisation. The article begins by providing context for the emergence of institutional child abuse as a social issue. A brief overview of key themes and debates in the interdisciplinary literature is then offered, and a critical gap in current scholarship is identified in relation to activism. Drawing on illustrative examples of activist mobilisation, both in the form of survivor narratives and strategies aimed at influencing policy, the article sets out how a sociology of activism in the field of historical institutional child abuse might proceed. Through attention to the social dynamics of activism, and conceptualisation of collective action in this domain as a social movement, the article provides new insights for the field and an alternative to sociological theorisation of responses to historical institutional child abuse as simply constituting a public scandal or moral panic.
Evaluation and visualization of facial massage effects by using ultraviolet stereo‐image correlation
Authors: Zhang Yuelin , Sunamura Fumika , Bamba Shiomi , Arikawa Shuichi , Yoneyama Satoru , Motonami Kaori , Matsushima Takashi , Numata Tadashi
Published: December 2019

Background/purpose

This study proposes a technique for visualizing the effect of facial massage using stereo‐image correlation with melanin pigment.

Method

In this method, the melanin pigment of a subject's face is made visible by using an ultraviolet light and utilized as a random pattern for stereo‐image correlation. Stereo‐pair images of the face with the melanin pigment before and after facial massage are recorded using a desk‐sized measurement equipment. Then, the deformation of the face by the massage can be obtained based on the principle of stereovision. The effectiveness of the proposed method is demonstrated by applying it to the massage effect evaluation of eight subjects (females in their 40s).

Results

The results show that the massage effect can be visualized from the displacement and strain distributions across the face obtained by the proposed method. In addition, it is observed that the face is displaced significantly by the massage and individual differences between the subjects can be captured.

Conclusion

The proposed method is effective for evaluating the effect of a facial massage when the painted pattern disappears due to the applied cream during the massage.
Soil physiology discriminates between no‐till agricultural soils with different crop systems on winter season
Authors: Frene Juan P. , Gabbarini Luciano A. , Wall Luis G.
Published: December 2019

Community level physiological profiles (CLPPs) were used to characterize soils with two contrasting no‐till agricultural practices in terms of crop rotation, looking for differences in soil physiology according to management: ‘good agricultural practices (GAP), based on crop rotation, and monocropping agriculture considered as poor agricultural practices (PAP); soils from nearby natural environments (NE) were used as reference. Soils from productive fields of the central Argentine Pampas were sampled in summer and winter. Treatments were replicated at four places along a 400‐km east–west transect, between longitudinal parallels 31° to 33°S. The CLPPs assay was based on either basal respiration or substrate‐induced respiration using different C sources, with or without additional nitrogen as a mineral amendment, to mimic fertilizer application effects. CLPPs allowed discrimination between soils with different agricultural practices, despite the differences in the texture and mineralogy of the soils at each replicate site. NE soils were significantly different to agriculture soils based on 70% of the estimated CLPPs parameters. The differences between GAP and PAP soils by CLPPs data were supported by 50% of the estimated parameters in winter and only by 12.5% of them in summer. The Euclidean distance between GAP and PAP increased 102% in winter compared with summer. Additional N to the incubation did not significantly modify the result. Coumaric and propionic acids appeared to be good substrates for discrimination between different agriculture practices by CLPPs.
The NIN‐like protein 5 (ZmNLP5) transcription factor is involved in modulating the nitrogen response in maize
Authors: Ge Min , Wang Yuancong , Liu Yuhe , Jiang Lu , He Bing , Ning Lihua , Du Hongyang , Lv Yuanda , Zhou Ling , Lin Feng , Zhang Tifu , Liang Shuaiqiang , Lu Haiyan , Zhao Han
Published: December 2019

Maize exhibits marked growth and yield response to supplemental nitrogen (N). Here, we report the functional characterization of a maize NIN‐like protein ZmNLP5 as a central hub in a molecular network associated with N metabolism. Predominantly expressed and accumulated in roots and vascular tissues, ZmNLP5 was shown to rapidly respond to nitrate treatment. Under limited N supply, compared with that of wild‐type (WT) seedlings, thezmnlp5mutant seedlings accumulated less nitrate and nitrite in the root tissues and ammonium in the shoot tissues. Thezmnlp5mutant plants accumulated less nitrogen than the WT plants in the ear leaves and seed kernels. Furthermore, the mutants carrying the transgenicZmNLP5cDNA fragment significantly increased the nitrate content in the root tissues compared with that of thezmnlp5mutants. In thezmnlp5mutant plants, loss of the ZmNLP5 function led to changes in expression for a significant number of genes involved in N signalling and metabolism. We further show that ZmNLP5 directly regulates the expression of nitrite reductase 1.1 (ZmNIR1.1) by binding to the nitrate‐responsivecis‐element at the 5′ UTR of the gene. Interestingly, a natural loss‐of‐function allele ofZmNLP5in Mo17 conferred less N accumulation in the ear leaves and seed kernels resembling that of thezmnlp5mutant plants. Our findings show that ZmNLP5 is involved in mediating the plant response to N in maize.
"To Gild Refined Gold," or What Mozart Didn't Want Us to Embellish
Authors: Rom Uri B.
Published: December 2019

The question of adding embellishments in music performance is generally regarded from a primarily practical perspective. In this article I make a case for embellishments as an object of music-theoretical inquiry in their own right. While exploring this question mainly in conjunction
with Mozart's music for solo piano, I address the more fundamental question of what makes a given moment in the music suitable for added ornamentation. Tolerance to embellishment is defined as a quality of the melodic surface tantamount to the flexibility and exchangeability of melodic formulations
with variants. Thus defined, only some of the embellishments notated by composers are indicative of a flexible melodic surface (optional embellishments), whereas others are shown to be irreducible owing to their participation in substantive thematic processes (obligatory embellishments). My
investigation focuses on embellishments introduced in sonata-form recapitulations and other types of recapitulatory restatements (e. g., the return of the refrain in the rondo form). A movement's form and tempo are shown to affect its amenability to added ornamentation. At a local level, I
draw on aspects of music perception and musical memory to account for a correlation between a passage's temporal position in the movement and its suitability for added embellishments. I conclude by pointing to a Mozart-specific category of unembellishable motives, demonstrably intended by
the composer to be performed with no decoration. Engaging in a dialogue with Robert Levin's recorded embellished version of the slow movement of Mozart's Piano Concerto in A major, K. 488, this primarily theoretical discussion also leads to some tentative practical implications for performance.
Effects of the Cross-Sectional Area of a Volute on Suction Recirculation and Cavitation in a Centrifugal Pump
Authors: Shim Hyeon-Seok , Kim Kwang-Yong
Published: December 2019

The effects of the cross-sectional area of a volute on suction recirculation and cavitation in a centrifugal pump were investigated. The pump performance and fluid flow were analyzed using both steady and unsteady three-dimensional Reynolds-averaged Navier–Stokes analyses. The shear stress transport (SST) model was adopted as a turbulence closure model, and a simplified Rayleigh–Plesset cavitation model and a homogeneous two-phase mixture model were used to simulate the cavitating flow inside the pump. A constant to determine the designed circumferential velocity of the volute was selected as the geometric parameter for a parametric study. The hydraulic efficiency, head coefficient, blockage in front of the impeller, and critical cavitation number for a head-drop of 3% were selected as the performance parameters to evaluate the hydraulic performance. The results show that unlike the blockage, the hydraulic and suction performances were affected significantly by the volute shape. Both steady and unsteady flow analyses showed that the onset and development of suction recirculation were relatively unaffected by the volute geometry and the best efficiency point of the pump.
A Standardized Representation of Convolutional Neural Networks for Reliable Deployment of Machine Learning Models in the Manufacturing Industry
Authors: Ferguson Max , Jeong Seongwoon , Law Kincho H. , Levitan Svetlana , Narayanan Anantha , Burkhardt Rainer , Jena Tridivesh , Lee Yung-Tsun Tina
Published: December 2019

The use of deep convolutional neural networks is becoming increasingly popular in the engineering and manufacturing sectors. However, managing the distribution of trained models is still a difficult task, partially due to the limitations of standardized methods for neural network representation. This paper seeks to address this issue by proposing a standardized format for convolutional neural networks, based on the Predictive Model Markup Language (PMML). A number of pre-trained ImageNet models are converted to the proposed PMML format to demonstrate the flexibility and utility of this format. These models are then fine-tuned to detect casting defects in Xray images. Finally, a scoring engine is developed to evaluate new input images against models in the proposed format. The utility of the proposed format and scoring engine is demonstrated by benchmarking the performance of the defect-detection models on a range of different computation platforms. The scoring engine and trained models are made available at https://github.com/maxkferg/python-pmml.
Modeling and Analysis of Leaf Spring Based Double Parallel-Guiding Mechanism Considering Thermal Effect
Authors: Lu Shuaishuai , Yan Peng
Published: December 2019

In the present paper, we take the leaf spring based double parallel-guiding mechanism (DPGM) as a particular case study to investigate a parametric model by considering the stress stiffening effect of the temperature variation based on the beam constraint model (BCM). In particular, a model with the temperature variation term of the DPGM is derived by incorporating the elastic stretch induced by the thermal effect of the leaf spring flexure into the BCM. Different from the traditional BCM, the compliance calculated by the established model is no longer only affected by the external loads, but the thermal deformation generated by the temperature variation. Therefore the derived model can describe both the load-nonlinearity and the thermal-nonlinearity. Based on the analysis results of a basic parallelogram module (BPM), we obtain a model of the DPGM, and the finite element analysis (FEA) method is adopted to verify the proposed model. The proposed model is a general parametric method to characterize the mechanical property of the DPGM, which can be further explored to support the optimization and control of motion systems composed of leaf spring based compliant mechanisms.
Sub-Optimal Control of Autonomous Wheel Loader With Approximate Dynamic Programming
Authors: Sardarmehni Tohid , Song Xingyong
Published: December 2019

Optimal control of wheel loaders in short loading cycles is studied in this paper. For modeling the wheel loader, the data from a validated diesel engine model is used to find a control oriented mean value engine model. The driveline is modeled as a switched system with three constant gear ratios (modes) of −60 for backwarding, 60 for forwarding, and zero for stopping. With these three modes, the sequence of active modes in a short loading cycle is fixed as backwarding, stopping, forwarding, and stopping. For the control part, it is assumed that the optimal path is known a priori. Given the mode sequence, the control objective is finding the optimal switching time instants between the modes while the wheel loader tracks the optimal path. To solve the optimal control problem, approximate dynamic programming is used. Simulation results are provided to show the effectiveness of the solution.
An Analysis of the Technical Feasibility of Off-Shore Wind Energy in the Philippines
Authors: Maandal Gerard Lorenz D. , Tamayao Mili-Ann M. , Danao Louis Angelo M.
Published: December 2019

The technical feasibility of off-shore wind energy in the Philippines is assessed. Geographic information system is utilized to integrate the different technical data into a single model. Off-shore wind speed data for five years at elevations 10m, 20m, 80m, and 100m from a local database was used as reference for the wind resource study. Two wind turbines were considered for the energy conversion component, Siemens SWT-3.6-120 and Senvion 6.2 M126. The wind speed data was interpolated to 90m and 95m using standard power law to match the hub heights of the turbines studied. The wind power density, wind power, and annual energy production were calculated from the interpolated wind speeds. Areas in the Philippines with capacity factor greater than 30% and performance greater than 10% were considered technically viable. Exclusion criteria were applied to narrow down the potential siting for offshore wind farms, namely, active submerged cables, local ferry routes, marine protected areas, reefs, oil and gas extraction areas, bathymetry, distance to grid, typhoons, and earthquakes. Several sites were determined to be viable with north of Cagayan having the highest capacity factor. The highest wind capacity factor for the offshore wind farms are located in north of Ilocos Norte (SWT-3.6-120: 54.48%–62.60%; 6.2M126: 54.04%–64.79%), north of Occidental Mindoro (SWT-3.6-120: 46.81%–60.92%; 6.2M126: 45.30%–62.60%) and southeast of Oriental Mindoro (SWT-3.6-120: 45.60%–59.52%; 6.2M126: 45.30%–62.60%). However, these sites are not acceptable due to technical, social, and political constraints. The constraints considered in the study are active submerged cables with a buffer of 5 km, local ferry routes with a buffer of 3km, marine protected areas with a buffer 3 km, reefs with a buffer of 3 km, oil and gas extraction areas with a buffer of 5 km, bathymetry less than 50m, distance to grid of within 120 km, historical typhoon tracks with greater than 250 kph and 50 km buffer, and historical earthquakes with greater than 6.5 magnitude with a buffer of 15 km. Upon application of these exclusion criteria, the potential sites for offshore wind farms are north of Cagayan, west of Rizal, north of Camarines Sur, north of Samar, southwest of Masbate, Dinagat Island, Guimaras, and northeast of Palawan.
Geometry Optimization of Cylindrical Flaps of Oscillating Wave Surge Converters Using Artificial Neural Network Models
Authors: Lin Chen-Chou , Chow Yi-Chih , Huang Yu-Yu
Published: December 2019

This paper presents an optimization algorithm based on the Artificial Neural Network (ANN) to determine the optimal shape, size, and density for the cylindrical flap of the Bottom-Hinged Oscillating Wave Surge Converter (BH-OWSC) that can extract maximal wave power under a given wave condition. Eight parameters are selected, and their upper and lower bounds are set at the initial stage, and then 64 cases with different combinatorial parametric settings are generated by the Design of Experiment process. The 64 cases are then fed into FLOW-3D to simulate the operations of the BH-OWSC under the given wave condition for calculating the capture factor, establishing a database for subsequent ANN data training purpose.

To search the maximal capture factor in the specific range of the flap models, we fed 107 random models with various levels of design parameters into the ANN model, which adopts the backpropagation architecture and one hidden layer with ten neuron cells. After three complete random searches, and by simulating the ANN-derived flap’s geometry using FLOW-3D, the result shows that a maximal capture factor of 1.824 can be obtained. The major geometric features of the flap with maximal capture factor are (1) the cylinder axis of the flap inclines to the opposite direction of incident wave propagation, (2) the cylinder’s sectional diameters are about the same size, and (3) the smaller flap density the better power capturing performance.
Development of a Cascade Elastocaloric Regenerator
Authors: Emaikwu Nehemiah , Catalini David , Muehlbauer Jan , Hwang Yunho , Takeuchi Ichiro , Radermacher Reinhard
Published: December 2019

Heat pumps based on the vapor compression cycle account for a significant portion of energy use around the world. However, growing demands for energy efficient and environmentally friendly technologies have created a need for new space conditioning approaches. Novel systems which use elastocaloric material have shown potential to replace traditional vapor compression due to high energy efficiency and use of environmentally friendly, solid-state refrigerants.

The solid-state refrigerants exhibit the elastocaloric effect, a phenomenon that occurs when metal alloys experience stress-induced reversible phase transformations resulting in latent heat release or absorption. Prototypes built in the Center for Environmental Energy Engineering have utilized the active elastocaloric regeneration (AER) operating method to develop high temperature gradients between the ends of a regenerative heat exchanger made of tubular elastocaloric material.

Though this schema significantly increases the temperature span developed by elastocaloric cooling devices, the current heat pump design leads to temperature degradation as a result of conduction along the length of the tubes in the regenerator. The novel regenerator concept presented in this work mitigates that issue by using short, thermally insulated tubes layers which also enables fluid flow over external surface areas of the material.
Exergy-Based Sustainability Analysis for Tile Production From Waste Plastics in Uganda
Authors: Balcom Paige , Carey Van P.
Published: December 2019

This paper presents an exergy-based sustainability analysis of manufacturing roof tiles from plastic waste in Uganda. Exergy analyses measure the sustainability of industrial processes. This work focuses specifically on the developing country context and on utilizing waste material. A summary of the current plastic waste situation in Uganda, the environmental and health issues associated with plastic waste, current means of recycling plastic waste into new products, and an analysis of the Ugandan roofing market are presented. The motivation for this study is to examine the resources utilized to improve overall exergy efficiency, reduce production costs, and reduce negative environmental impacts. The company, Resintile, is the only manufacturer of roof tiles from plastic waste in Uganda. Their tiles comprised mainly of sand and plastic waste are manufactured in an industrialized process involving drying, extrusion, and pressing. The exergy consumed at each stage including transportation is presented. The extruder consumes the majority of the exergy, but wrapping insulation around the barrel could save over 3 MJ, and a heat engine could provide over 7.5 MJ of usable exergy. The total exergy consumed to produce one batch of seventy-five tiles is over 122 MJ, the potentially recoverable exergy is over 5 MJ (4.3% of consumed exergy), and the realistic recoverable exergy is nearly 10.7 MJ (8.7% of consumed exergy). The realistic can be greater than the potential by adding a heat engine to the sand drying process to generate usable exergy rather than merely recover consumed exergy. Resintile’s plastic roof tiles save a net 86.3 kg of CO2 from entering the atmosphere per batch of tiles and adoption of the suggested improvements to the manufacturing process would save an additional 3.8 kg of CO2 per batch.
Assessment of a CFD-Based Machine Learning Approach on Turbulent Flow Approximation
Authors: Ziaei Dorsa , Hekmati Athar Seyyed Pooya , Goudarzi Navid
Published: December 2019

Computational fluid dynamics (CFD) simulation is usually a computationally expensive, memory demanding, and time consuming iterative process. These drawbacks limit the use of CFD, especially when either spatiotemporal scales or geometry complexity increases. This paper presents the preliminary results from the assessment of an approximation model for predicting non-uniform steady turbulent flows in a 3D domain, utilizing deep learning (DL) algorithms. In particular, the artificial neural network (ANN) approach uses most important variables data from currently CFD simulation results to link multi-variable input spaces (e.g. input speed and direction, geometry configuration) with multi-variable output space (e.g. velocity magnitude, pressure gradient) to obtain an efficient and accurate approximation of the entire velocity field for given input flow field characteristics. The results demonstrated higher computational speed with a similar accuracy using DL algorithms versus CFD simulation. This integrated approach can provide immediate feedback for real-time design iterations for the entire computational domain at the early stages of design. Hence, designers and engineers can easily generate immense amounts of design alternatives without facing the time-consuming task of evaluation and selection.
Supercritical Water Gasification of Ethanol for Fuel Gas Production
Authors: Pinkard Brian R. , Rasmussen Elizabeth G. , Kramlich John C. , Reinhall Per G. , Novosselov Igor V.
Published: December 2019

Supercritical water gasification of dilute ethanol at the industrial scale promises a sustainable route to bio-syngas production for use in combined cycle power plants. Cost-effective bio-syngas production would reduce reliance on fossil fuels for electricity generation and reduce greenhouse gas emissions by utilizing waste biomass resources. Continuous supercritical water gasification offers high reactant conversion at short residence times without an added catalyst. The decomposition of ethanol in supercritical water is studied in a continuous reactor at 560 °C, 25 MPa, residence times between 3 and 8 s, and a constant initial ethanol concentration of 8.1 wt%. High-resolution, in-situ Raman spectroscopy facilitates identification of reaction products. Significant yields of H2, CO, and CH4 indicate the dominance of a dehydrogenation reaction pathway at studied conditions, while minor yields of ethane indicate a secondary dehydration reaction pathway. Ethylene yields are virtually nonexistent, indicating rapid hydrogenation of ethylene to ethane at these conditions. Ethanol dehydrogenation to H2, CO, and CH4 results in an overall fuel value upgrade of 84.5 kJ/mol-EtOH. Dehydration of ethanol to ethane results in an overall fuel degradation of −3.8 kJ/mol-EtOH.
Numerical Simulation of a Composite Metal Foam-PCM Air Heat Exchanger Using Rod PTC Heating Elements
Authors: Talebizadeh Sardari Pouyan , Giddings Donald , Walker Gavin S. , Gillott Mark , Grant David
Published: December 2019

The aim of this paper is to study the charging/discharging process in a Latent heat exchanger for the purpose of space heating by using a composite metal foam/PCM. The composite PCM-air system is modelled in a 3-D CFD approach for the purpose of 8h charging during the night and 16h discharging during the daytime using the non-equilibrium thermal model to simulate the presence of a porous medium in the domain. For the charging process, rod Positive Temperature Coefficient (PTC) heating elements with constant temperature are selected to heat the PCM based on the maximum operating temperature of the PCM. For the discharging process, a blower is assumed to pass the air from the middle of the PCM container and so the air can gain heat and its temperature rises which is used then for space heating. RT70HC is also selected as the PCM material due to the high capacity of latent heat and suitable melting point for domestic usage. The system is studied according to the average liquid fraction and temperature of the PCM during both charging and discharging as well as the outlet temperature of the air during discharging. The results show that by using two rod heating elements with the diameter of 1cm, length of 25cm and temperature of 95°C, the melting process is performed in less than 8h. Furthermore, a uniform output temperature of almost 29.5°C is also achieved in the next 16h during the discharging process with the air mass flow rate of 0.04 kg/s.
Powder-Binder Jetting Large-Scale, Metal Direct-Drive Generators: Selecting the Powder, Binder, and Process Parameters
Authors: Hayes Austin C. , Whiting Gregory L.
Published: December 2019

Additive manufacturing enables the production of complex geometries extremely difficult to create with conventional subtractive methods. While good at producing complex parts, its limitations can be seen through its penetration into everyday manufacturing markets. Throughput limitations, poor surface roughness, limited material selection, and repeatability concerns hinder additive manufacturing from revolutionizing all but the low-volume, high-value markets. This work characterizes combining powder-binder jetting with traditional casting techniques to create large, complex metal parts. Specifically, we extend this technology to wind turbine generators and provide initial feasibility of producing complex direct-drive generator rotor and stator designs. In this process, thermal inkjet printer heads selectively deposit binder on hydroperm casting powder. This powder is selectively solidified and baked to remove moisture before being cast through traditional methods. This work identifies a scalable manufacturing process to print large-scale wind turbine direct drive generators. As direct-drive generators are substantially larger than their synchronous counterparts, a printing process must be able to be scaled for a 2–5 MW 2–6m machine. For this study, research on the powder, binder, and printing parameters is conducted and evaluated for scalability.
Supercritical CO2 Brayton Power Cycle for CSP With Packed Bed TES Integration and Cost Benchmark Evaluation
Authors: Trevisan Silvia , Guédez Rafael , Laumert Björn
Published: December 2019

The present work introduces an indirect supercritical CO2–air driven concentrated solar plant with a packed bed thermal energy storage. The proposed plant design enables a supercritical CO2 turbine inlet temperature of 800°C, overcoming the temperature limits imposed by the use of solar molten salts as primary heat transfer fluid. Furthermore, the packed bed thermal energy storage permits the decoupling between thermal power collection from the sun and electricity generation. Besides, the thermal energy storage unit grants operational flexibility and enlarges the plant capacity factor, making it as available as a conventional coal facility. A transient thermodynamic model of the integrated concentrating solar plant, including receiver, thermal energy storage, intermediate heat exchangers and supercritical CO2 power cycle has been developed. This same model has been used to evaluate the thermodynamic performance of the proposed plant design over a complete year. A similar model has been implemented to simulate a supercritical CO2 plant driven by a more traditional solar molten salt loop. A comparison of the thermodynamic performance of the two plant designs has been performed. A complete economic model has been developed in order to evaluate the economic viability of the proposed plant. Furthermore, a multi-objective optimization have been executed in order to assess the influence of the thermal energy storage size, supercritical CO2 turbine inlet temperature and plant solar multiple on the key performance indicators. Results show that the proposed indirect supercritical CO2–air driven with a packed bed thermal energy storage concentrated solar plant leads to improved thermo-economic performance with respect to the molten salts driven design. Enhancements in the power cycle efficiency and in the overall electricity production can be achieved, with a consequent reduction in the levelized cost of electricity. Particularly, for a design net electrical power production of 10MWe a minimum levelized cost of electricity has been calculated at 89.4 $/MWh for a thermal energy storage capacity of 13.9 hours at full load and a plant solar multiple of 2.47 corresponding to a capital investment of about 73.4 M$.
Using Molten Carbonate Fuel Cell Systems for CO2 With a Natural Gas Combined Cycle Operating at Part Load
Authors: Flores Robert , Brouwer Jack
Published: December 2019

Traditional carbon capture technology has been shown to effectively capture emissions, but at a cost of reducing power plant output. Molten carbonate fuel cell technology (MCFC) has the potential to be able to concentrate plant carbon emissions into a gas stream that is suitable for storage while boosting total plant power output. When considering this type of technology, the original purpose and function of the power plant must be considered. In particular, gas turbines (GT) based natural gas combined cycle (NGCC), which are capable of dynamic load following operation, are likely to need to maintain operational flexibility. This work explores the retrofit of an existing GT with MCFC technology for carbon capture when the plant is operated at part load. Physical models for major plant components are built and used to select optimal operating set points such that operating cost is minimized. Special attention is given to ensuring feasible operation across all engine components. The results show MCFC operational parameters that minimize change in fuel cell operating conditions when the gas turbine is operated at part load.
Efficiency Improvement of a Liquid Piston Compressor Using Metal Wire Mesh
Authors: Patil Vikram C. , Liu Jun , Ro Paul I.
Published: December 2019

Intermittent nature of power from renewable energy resources demands a large scale energy storage system for their optimal utilization. Compressed air energy storage systems have the potential to serve as long-term large-scale energy storage systems. Efficient compressors are needed to realize a high storage efficiency with compressed air energy storage systems. Liquid piston compressor is highly effective in achieving efficient near-isothermal compression. Compression efficiency of the liquid piston can be improved with the use of heat transfer enhancement mechanisms inside the compression chamber. A high rate of heat transfer can be achieved with the use of metal wire mesh in the liquid piston compressor. In this study, metal wire meshes of aluminum and copper materials in the form of Archimedean spiral are experimentally tested in a liquid (water) piston compressor. Experiments are conducted for the compression of air from atmospheric pressure to 280–300 kPa pressure at various stroke times of compression. The peak air temperature is reduced by 26–33K with the use of metal wire mesh inside the liquid piston compressor. Both the materials are observed to be equally effective for temperature abatement. The use of metal wire mesh in liquid piston shifts the compression process towards near-isothermal conditions. Furthermore, the isothermal efficiency of compression is evaluated to assess the potential of efficiency improvement with this technique. The metal wire mesh was observed to improve isothermal compression efficiency to 88–90% from the base efficiency of 82–84%. A 6–7% improvement in efficiency was observed at faster compression strokes signifying effectiveness of metal wire mesh to accomplish efficient compression with high power density. Further investigations to evaluate the optimal configuration of the metal wire mesh will be useful to achieve additional improvement in efficiency.
Artificial Intelligence for Optimal Sitting of Individual and Networks of Wind Farms
Authors: Hekmati Athar Seyyed Pooya , Ziaei Dorsa , Goudarzi Navid
Published: December 2019

Renewable Energy (RE)-based power production often comes with certain challenges in variability and uncertainty of generated electricity. One promising solution to tackle these challenges is developing a network of RE power plants with sites located far enough from each other that experience different weather patterns. Most of the site selection-related literature use Geographical Information Systems to determine the studied site RE suitability. This work converts the site selection into a numerical problem through a novel Networked Renewable Power Plant Site Selection model and solves it by employing optimization techniques. To enhance the accuracy of the results, it compares a set of criteria for individual and network of sites at different regions to determine the exact locations for RE plant developments. The Analytical Hierarchy Process is used for criteria weighing. The state-of-the-art meta-heuristic Bare Bones of Fireworks algorithm offer a simple, fast, yet accurate approach to solve the optimization. The proposed method is applied on North Carolina wind farms for both individual and a network of sites. The results identified the areas with the highest wind capacity potential for individual or a network of wind farms in North Carolina. The identified suitable areas were verified with Amazon Wind Farm US East.
Gas Turbine and Combined Cycle Generator Dewpoints: Worse Than Expected
Authors: Warren Ted , Ketchem James Dustin
Published: December 2019

Many hydrogen cooled generators operate with no hydrogen dryer.

Plant personnel offer a variety of reasons:

• The OEM didn’t supply a dryer to begin with.

• Manual Reactivations are too labor intensive.

• Don’t think their generator is wet.

• Because they have a Gas Turbine (no steam), they don’t think there is anywhere for the hydrogen to pick up moisture.

• Don’t think moisture matters.

• Purity is good so everything must be fine.

• They employ “Bleed and Feed” or “Scavenging” to deal with purity / moisture issues.

Generator manufacturers recommend keeping the hydrogen dry. We had a theory that many generators were much wetter than was realized or recommended by the manufacturers. We took portable dewpoint analyzers to the plants to test the actual dewpoint of the hydrogen.

This paper presents our results.

Over 90% of the generators tested were found to have hydrogen dewpoints higher than the generator manufacturer’s recommendation.
Simulation-aided design of very-high-frequency excited nitrogen plasma confinement using a shield plate
Authors: Isobe Yasuhiro , Sakai Takayuki , Suguro Kyoichi , Miyashita Naoto , Kondo Hiroki , Ishikawa Kenji , Wilson Amalraj Frank , Shimizu Naohiro , Oda Osamu , Sekine Makoto , Hori Masaru
Published: December 2019

Nitrogen atoms are versatile for nitridation applications and do not lead to plasma-induced damage. Large-sized wafer processing demands a uniform supply of nitrogen atoms produced in a high-density very-high-frequency excited plasma of N2 without ammonia. The confinement of plasma through the use of a plasma shield plate (PSP) allows the samples to be separated in a downstream chamber. Generation and transport of N atoms were computationally simulated, and the PSP designs were implemented by PSP parameterization. The supply of high-density N radicals to the sample stage was optimally designed with sufficiently small holes and thin PSP to satisfy an aspect ratio of thickness-to-hole-diameter of less than 2.5.
Synthesis and study of γ-Fe2O3 and CoFe2O4 based ferrofluids by means of spectroscopic Mueller matrix ellipsometry
Authors: Battie Yann , Stchakovsky Michel , Neveu Sophie , Jamon Damien , Garcia-Caurel Enric
Published: December 2019

Ferrofluids are colloidal suspensions generally composed of ferromagnetic or ferrimagnetic nanoparticles (NPs). In the present study, the authors have focused on the ellipsometric characterization of two types of ferrofluids: one constituting maghemite (γ-Fe2O3) NPs and the other cobalt ferrite (CoFe2O4) NPs. The optical properties of the NPs are extracted from the ellipsometric spectra by using the Maxwell–Garnett effective medium approximations. As expected, Mueller matrix measurements reveal that the ferrofluid becomes anisotropic under the influence of a magnetic field. The authors correlate this anisotropy to the preferential orientation of NPs along the magnetic field.