bluuebunny/crossref_metadata_2025 huggingface dataset:
Nanoparticle‐based measurements of pH and O2 dynamics in the rhizosphere of Zostera marina L.: effects of temperature elevation and light‐dark transitions
Authors: Elgetti Brodersen Kasper , Koren Klaus , Lichtenberg Mads , Kühl Michael
Published: March 2016

Seagrasses can modulate the geochemical conditions in their immediate rhizosphere through the release of chemical compounds from their below‐ground tissue. This is a vital chemical defence mechanism, whereby the plants detoxify the surrounding sediment.

Using novel nanoparticle‐based optical O2 and pH sensors incorporated in reduced and transparent artificial sediment, we investigated the spatio‐temporal dynamics of pH and O2 within the entire rhizosphere of Zostera marina L. during experimental manipulations of light and temperature. We combined such measurements with O2 microsensor measurements of the photosynthetic productivity and respiration of seagrass leaves.

We found pronounced pH and O2 microheterogeneity within the immediate rhizosphere of Z. marina, with higher below‐ground tissue oxidation capability and rhizoplane pH levels during both light exposure of the leaf canopy and elevated temperature, where the temperature‐mediated stimuli of biogeochemical processes seemed to predominate. Low rhizosphere pH microenvironments appeared to correlate with plant‐derived oxic microzones stimulating local sulphide oxidation and thus driving local proton generation, although the rhizoplane pH levels generally where much higher than the bulk sediment pH.

Our data show that Z. marina can actively alter its rhizosphere pH microenvironment alleviating the local H2S toxicity and enhancing nutrient availability in the adjacent sediment via geochemical speciation shift.
Psychodermatologic Effects of Atopic Dermatitis and Acne: A Review on Self‐Esteem and Identity
Authors: Nguyen Catherine M. , Koo John , Cordoro Kelly M.
Published: March 2016

Atopic dermatitis (AD) and acne vulgaris are among the most‐prevalent skin diseases in children. Both have been well documented in the literature to have significant negative effects on quality of life. Herein, we discuss the results of a comprehensive literature review aimed at assessing the impact of acne and AD on self‐esteem and identity. We highlight clinical tools for their assessment and offer coping strategies for patients and families. Multiple factors including relationships with parents and classmates, sports participation, and the sex of the patient contribute to the development of self‐esteem and identity in individuals with AD and acne. Atopic dermatitis was found to have significant behavioral effects on children, ultimately resulting in a lack of opportunity to develop proper coping. AD had a more‐prominent role in identity formation and gender roles in girls. Acne vulgaris was found to have a more direct effect on self‐esteem, self‐confidence and identity, especially in girls. The Cutaneous Body Image Scale is reviewed and offered as an easy and reliable tool to evaluate a patient's mental perception of the appearance of their skin. Coping strategies that may be offered to patients and families include empowerment and cognitive adaptation.
Anti‐Tumor Necrosis Factor α–Related Psoriatic Lesions in Children with Inflammatory Bowel Disease: Case Report and Systematic Literature Review
Authors: Romiti Ricardo , Araujo Karin Milleni , Steinwurz Flavio , Denadai Rafael
Published: March 2016

We report a child with Crohn's disease and infliximab‐induced guttate psoriasis. We also performed a systematic literature review on this intriguing paradoxical phenomenon in children with inflammatory bowel disease.
Association Between Discoid Lupus Erythematosus and Chronic Granulomatous Disease—Report of Two Cases and Review of the Literature
Authors: Xie Charles , Cole Theresa , McLean Catriona , Su John C.
Published: March 2016

Discoid lupus erythematosus (DLE) is known to be associated with chronic granulomatous disease (CGD), but most DLE occurs in female carriers of X‐linked CGD, with few reports of these lesions in CGD‐affected individuals—this observation is unexplained. We describe two cases of DLE‐like lesions in boys with CGD: one boy with partial neutrophil function and another whose lesions were related to voriconazole use. Reviewing other previously reported cases, we conclude that the risk of developing DLE‐like lesions appears to be greater primarily in two subsets of the population with CGD: those with partial neutrophil function and those with near‐absent neutrophil function in whom there is a second trigger. In light of recent literature on the role of neutrophils in lupus pathogenesis, we propose that pathogenesis of DLE in CGD may be related to NETosis, neutrophil dysfunction and a deficiency of reactive oxygen species, which medications such as voriconazole also influence.
Paratacamite from Gypsum Veins in Sandstones of the Kuqa Basin, Xinjiang, China: Implications for a New Epigenetic Cu Enrichment Mechanism
Authors: Cao Yangtong , Liu Chenglin , Jiao Pengcheng , Wang Chunlian
Published: March 2016

The Kuqa Basin filled with Paleogene evaporite series is located in the northeast of the Tarim Basin, Xinjiang, China. It is famous for sandstone‐hosted Cu deposits formed by synsedimentary processes. However, our recent studies reveal that there has been another Cu mineralization mechanism in this basin. Field investigations show that there is a close relationship among faults, salt domes, and brine. Cu deposits are mainly located in two east–west‐trending anticlinal belts in the basin, adjacent to salt domes in the belts. Cu minerals in gypsum veins of the Jidike and Kangcun formations have been investigated by SEM, EDS, and X‐ray diffraction methods. The occurrence of paratacamite in gypsum veins has been reported to coexist with glauberite and halite in the joint planes of sandstones. In addition, it occurs accompanying residual crystal salt encrustation in limestone fractures, or in sandstones in dendritic form. These features indicate that the surface‐Cu enrichment in the Kuqa Basin might have originated from Cu‐bearing brine in the underlying evaporite units, which migrated upward along fractures. In addition, the presence of H2S in the east–west fault belt in the Kuqa Basin, and the discovery of surface sulfur, calcium carbonate, and covellite, suggest thermochemical sulfate reduction near salt domes in the deeper parts of the rock units. This process resulted in the generation of reduced brine and provided a favorable environment for Cu enrichment. Therefore, the surface‐Cu mineralization near salt domes is interpreted to be the result of Cu‐bearing brine migrating upward to the surface along faults (or joints) following the intrusion of deep salt domes. The geological evidence indicates the presence of reducing brine and Cu‐bearing brine near the salt dome in the deeper rocks of the Kuqa Basin, thus making the intrusive contact zone of the salt dome a favorable site for the epigenetic enrichment of Cu. Our study demonstrates that Cu enrichment in the Kuqa Basin resulted not only from synsedimentary deposition but also through epigenetic enrichment associated with salt dome intrusion and brine‐rich fluids.
Impact of Firearm Availability and Gun Regulation on State Suicide Rates
Authors: Kposowa Augustine , Hamilton David , Wang Katy
Published: March 2016

Past studies on suicide have investigated the association of firearm ownership and suicide risk in the United States. The aim of the present study was to build on previous work by examining the impact of firearm storage practices and the strictness of firearm regulation on suicide rates at the state level. Data were compiled from primarily three sources. Suicide and firearm ownership information was obtained from the Centers for Disease Control and Prevention. Strictness of handgun regulation was derived from figures available at the Law Center to Prevent Violence, and controls were taken from the US Bureau of the Census. Mixed models were fitted to the data. Household firearm ownership was strongly associated with both suicide by all mechanisms, and firearm suicide. Storage practices had especially elevated consequences on suicide rates. Percent with loaded guns and gun readiness increased suicide rates, and strictness of gun regulation reduced suicide rates. Ready access to firearms can make a difference between life and death. Loaded and unlocked firearms within reach become risk factors for fatal outcomes from suicidal behavior. Future research might want to examine ways of obtaining more recent data on individual firearm ownership. This study proposes several policy recommendations for suicide prevention.
In kidney transplant recipients with BK polyomavirus infection, early BK nephropathy, microvascular inflammation, and serum creatinine are risk factors for graft loss
Authors: Mohamed M. , Parajuli S. , Muth B. , Astor B.C. , Panzer S.E. , Mandelbrot D. , Zhong W. , Djamali A.
Published: March 2016

Background

Little information is available on the risk factors for graft loss in kidney transplant recipients with BK polyomavirus (BKPyV) nephropathy (BKVN) in the presence or absence of antibody‐mediated rejection (AMR).

Methods

We examined the risk factors for graft loss in consecutive kidney allograft recipients with biopsy‐confirmed BKVN, with or without concomitant AMR.

Results

A total of 1904 kidney transplants were performed at our institution during 2005–2011. Of these, 330 (17.33%) were diagnosed with BKPyV viremia, and 69 were diagnosed with BKVN (3.6%). Eleven patients had a concomitant diagnosis of AMR. Patients with AMR were characterized by significantly higher peak panel‐reactive antibody, retransplant rates, and desensitization preconditioning at the time of transplantation, as well as microvascular inflammation (MVI = glomerulitis + peritubular capillaritis), C4d score, and donor‐specific antibody at the time of diagnosis (P ≤ 0.01). Treatment with plasma exchange, intravenous immunoglobulin, and cidofovir was more prevalent in this group (P ≤ 0.02). Univariate analyses assessing the risk factors for graft loss in all patients with BKVN, identified an independent association of African‐American race, deceased‐donor transplantation, serum creatinine (Scr), MVI, and early disease (BKVN within 6 months of transplant) with poor outcomes. Multivariate analyses retained only 3 variables: Scr >2 mg/dL (hazard ratio [HR] = 4.3, 95% confidence interval [CI] 1.9–9.7, P = 0.0004), early BKVN (HR = 2.7, 95% CI 1.3–5.3, P = 0.004), and MVI (HR = 1.8, 95% CI 1.2–2.8, P = 0.008).

Conclusions

These observations suggest that, in patients with BK infection, early BKVN, Scr >2, and MVI are predictors of poor outcomes. Further studies are needed to determine effective treatment strategies for BKVN, with or without AMR.
Synthetic redesign of plant lipid metabolism
Authors: Haslam Richard P. , Sayanova Olga , Kim Hae Jin , Cahoon Edgar B. , Napier Johnathan A.
Published: March 2016

Plant seed lipid metabolism is an area of intensive research, including many examples of transgenic events in which oil composition has been modified. In the selected examples described in this review, progress towards the predictive manipulation of metabolism and the reconstitution of desired traits in a non‐native host is considered. The advantages of a particular oilseed crop, Camelina sativa, as a flexible and utilitarian chassis for advanced metabolic engineering and applied synthetic biology are considered, as are the issues that still represent gaps in our ability to predictably alter plant lipid biosynthesis. Opportunities to deliver useful bio‐based products via transgenic plants are described, some of which represent the most complex genetic engineering in plants to date. Future prospects are considered, with a focus on the desire to transition to more (computationally) directed manipulations of metabolism.
Comprehensive US government program for dried plasma development
Authors: Pusateri Anthony E. , Given Michael B. , Macdonald Victor W. , Homer Mary J.
Published: March 2016

Transfusion of plasma early after severe injury has been associated with improved survival. There are significant logistic factors that limit the ability to deliver plasma where needed in austere environments, such as the battlefield or during a significant civilian emergency. While some countries have access to more logistically supportable dried plasma, there is no such product approved for use in the United States. There is a clear need for a Food and Drug Administration (FDA)‐approved dried plasma for military and emergency‐preparedness uses, as well as for civilian use in remote or austere settings. The Department of Defense (DoD) and Biomedical Advanced Research and Development Authority are sponsoring development of three dried plasma products, incorporating different technologic approaches and business models. At the same time, the DoD is sponsoring prospective, randomized clinical studies on the prehospital use of plasma. These efforts are part of a coordinated program to provide a dried plasma for military and civilian applications and to produce additional information on plasma use so that, by the time we have an FDA‐approved dried plasma, we will better understand how to use it.
Bioenergetic profiling of platelet mitochondria during storage: 4°C storage extends platelet mitochondrial function and viability
Authors: Bynum James A. , Adam Meledeo M. , Getz Todd M. , Rodriguez Armando C. , Aden James K. , Cap Andrew P. , Pidcoke Heather F.
Published: March 2016

BACKGROUND

Platelets (PLTs) are stored at room temperature (RT) to preserve in vivo circulation time, but PLT quality is degraded. The PLT storage lesion is mitigated by refrigeration, but questions remain regarding effects of cold storage (4°C) on mitochondrial function. Mitochondrial reactive oxygen species (ROS) generation may adversely affect PLT function and viability during storage, and refrigeration may mitigate these effects.

STUDY DESIGN AND METHODS

PLTs were stored under two temperature conditions (RT, 20‐24°C; or 4°C, 1‐6°C) and four storage durations (baseline [BL] and Days 3, 5, and 7). Mitochondrial respiration and maximal oxygen utilization were assessed with high‐resolution respirometry. Mitochondrial ROS generation was assessed using a superoxide stain. Rotational thromboelastometry (ROTEM) was performed at BL and on Day 5 to assess PLT function. Collagen‐induced PLT aggregation was measured by impedance aggregometry.

RESULTS

Mitochondrial ROS in 4°C‐stored samples were lower compared to RT and retained a greater capacity to generate ROS after activation. Mitochondrial respiration and maximal mitochondrial utilization was conserved in PLTs stored at 4°C. ROTEM data demonstrated that net maximum clot firmness was higher in 4°C samples compared to RT and prevented fibrinolysis. The aggregation response to collagen was preserved in the 4°C samples versus RT‐stored PLTs. Aggregation impairment correlated well with attenuated mitochondrial respiration and elevated production of intracellular mitochondrial ROS in the RT PLTs.

CONCLUSION

Mitochondrial damage and ROS production may contribute to loss of PLT viability during storage, whereas cold storage is known to preserve PLT function. Here we demonstrate that 4°C storage results in less oxidant stress and preserves mitochondrial function and potential compared to RT.
Platelets regulate vascular endothelial stability: assessing the storage lesion and donor variability of apheresis platelets
Authors: Baimukanova Gyulnar , Miyazawa Byron , Potter Daniel R. , Muench Marcus O. , Bruhn Roberta , Gibb Stuart L. , Spinella Philip C. , Cap Andrew P. , Cohen Mitchell J. , Pati Shibani
Published: March 2016

BACKGROUND

In current blood banking practices, platelets (PLTs) are stored in plasma at 22°C, with gentle agitation for up to 5 days. To date, the effects of storage and donor variability on PLT regulation of vascular integrity are not known.

STUDY DESIGN AND METHODS

In this study, we examined the donor variability of leukoreduced fresh (Day 1) or stored (Day 5) PLTs on vascular endothelial barrier function in vitro and in vivo. In vitro, PLT effects on endothelial cell (EC) monolayer permeability were assessed by analyzing transendothelial electrical resistances (TEER). PLT aggregation, a measure of hemostatic potential, was analyzed by impedance aggregometry. In vivo, PLTs were investigated in a vascular endothelial growth factor A (VEGF‐A)‐induced vascular permeability model in NSG mice, and PLT circulation was measured by flow cytometry.

RESULTS

Treatment of endothelial monolayers with fresh Day 1 PLTs resulted in an increase in EC barrier resistance and decreased permeability in a dose‐dependent manner. Subsequent treatment of EC monolayers with Day 5 PLTs demonstrated diminished vasculoprotective effects. Donor variability was noted in all measures of PLT function. Day 1 PLT donors were more variable in their effects on TEER than Day 5 PLTs. In mice, while all PLTs regardless of storage time demonstrated significant protection against VEGF‐A–induced vascular leakage, Day 5 PLTs exhibited reduced protection when compared to Day 1 PLTs. Day 1 PLTs demonstrated significant donor variability against VEGF‐A–challenged vascular leakage in vivo. Systemic circulating levels of Day 1 PLTs were higher than those of Day 5 PLTs

CONCLUSIONS

In vitro and in vivo, Day 1 PLTs are protective in measures of vascular endothelial permeability. Donor variability is most prominent in Day 1 PLTs. A decrease in the protective effects is found with storage of the PLT units between Day 1 and Day 5 at 22°C, thereby suggesting that Day 5 PLTs are diminished in their ability to attenuate vascular endothelial permeability.
Has China Displaced its Competitors in High‐tech Trade?
Authors: Pham Cong S. , Nguyen Xuan , Sgro Pasquale , Tang Xueli
Published: March 2016

This paper empirically investigated the extent to which China displaced its competitors in high‐tech exports using disaggregated data for the period 1992–2013. To address the endogeneity problem, we used a comprehensive set of instruments for Chinese high‐tech exports in relevant markets, including China's GDP and distances to those markets. Results of our IV regressions revealed that in most of the high‐tech sectors, Chinese exports had displaced the exports of its developing competitors such as India, South American exporters like Brazil and Mexico, and South‐East Asian countries like Malaysia, Singapore, Thailand and Vietnam, especially in the period prior to the 2007–08 global financial crisis. Yet, Chinese exports had been associated with more high‐tech exports of developed exporters like OECD countries, South Korea and Japan. Our findings suggest that while China became the world's top high‐tech exporter, its high‐tech exported products had been substitutes to those of other developing and emerging economies but complementary to that of developed economies.
COMPARISON OF ULTRASOUND‐GUIDED VS. STANDARD LANDMARK TECHNIQUES FOR TRAINING NOVICE OPERATORS IN PLACING NEEDLES INTO THE LUMBAR SUBARACHNOID SPACE OF CANINE CADAVERS
Authors: Etienne Anne‐Laure , Delguste Catherine , Busoni Valeria
Published: March 2016

The standard technique for placing a needle into the canine lumbar subarachnoid space is primarily based on palpation of anatomic landmarks and use of probing movements of the needle, however, this technique can be challenging for novice operators. The aim of the current observational, prospective, ex vivo, feasibility study was to compare ultrasound‐guided vs. standard anatomic landmark approaches for novices performing needle placement into the lumbar subarachnoid space using dog cadavers. Eight experienced operators validated the canine cadaver model as usable for training landmark and ultrasound‐guided needle placement into the lumbar subarachnoid space based on realistic anatomy and tissue consistency. With informed consent, 67 final year veterinary students were prospectively enrolled in the study. Students had no prior experience in needle placement into the lumbar subarachnoid space or use of ultrasound. Each student received a short theoretical training about each technique before the trial and then attempted blind landmark‐guided and ultrasound‐guided techniques on randomized canine cadavers. After having performed both procedures, the operators completed a self‐evaluation questionnaire about their performance and self‐confidence. Total success rates for students were 48% and 77% for the landmark‐ and ultrasound‐guided techniques, respectively. Ultrasound guidance significantly increased total success rate when compared to the landmark‐guided technique and significantly reduced the number of attempts. With ultrasound guidance self‐confidence was improved, without bringing any significant change in duration of the needle placement procedure. Findings indicated that use of ultrasound guidance and cadavers are feasible methods for training novice operators in needle placement into the canine lumbar subarachnoid space.
Precarious Workers’ Movements and the Neoliberal State
Authors: Meyer Rachel
Published: March 2016

How can we best conceptualize working‐class mobilization in the post‐Fordist regime of flexible accumulation? With the increasing precariousness of employment, how do workers press their demands? While the emphasis thus far has been on the melding of workplace and community organizing, which is a hallmark of “social movement unionism,” I argue that there is a countervailing trend afoot that has received far less attention—that is, a bifurcation of strategies. Only those select workers who are in powerful structural locations, such as transportation and distribution workers, are in a position to take the economic route while the swelling ranks of the precariat have turned instead to the political sphere to press their demands. Additionally, I address what this bifurcation means for labor's power and working‐class formation. Does the separation of economic and political protest lead to a weakened working class? Such a separation has been thought to undermine class‐based solidarities, with community identities undermining workplace‐based ones. I argue, however, that the contemporary context is different in that precarious workers’ mobilizations in the community have become explicitly class‐based. In contrast to the long‐standing notion of the workplace as the hotbed of working‐class consciousness, the community has emerged as a locus of class‐based perspectives and solidarities. Throughout I emphasize not just strategy and material gain for the working class, but also shifts in civil society, organizations, and subjectivity. My argument is developed through a case study of the Chicago Jobs and Living Wage Campaign, which is then compared to other cases of precarious worker mobilization around the globe. Examining the tensions inherent in precarious workers’ political mobilization in the context of the post‐Fordist neoliberal state, the study has implications for labor and social movements, class formation, citizenship, and contemporary capitalism.
Stimulation of dopamine D2‐like receptors in the lumbosacral defaecation centre causes propulsive colorectal contractions in rats
Authors: Naitou Kiyotada , Nakamori Hiroyuki , Shiina Takahiko , Ikeda Azusa , Nozue Yuuta , Sano Yuuki , Yokoyama Takuya , Yamamoto Yoshio , Yamada Akihiro , Akimoto Nozomi , Furue Hidemasa , Shimizu Yasutake
Published: March 2016

Key points

The pathophysiological roles of the CNS in bowel dysfunction in patients with irritable bowel syndrome and Parkinson's disease remain obscure.

In the present study, we demonstrate that dopamine in the lumbosacral defaecation centre causes strong propulsive motility of the colorectum.

The effect of dopamine is a result of activation of sacral parasympathetic preganglionic neurons via D2‐like dopamine receptors.

Considering that dopamine is a neurotransmitter of descending pain inhibitory pathways, our results highlight the novel concept that descending pain inhibitory pathways control not only pain, but also the defaecation reflex.

In addition, severe constipation in patients with Parkinson's disease can be explained by reduced parasympathetic outflow as a result of a loss of the effect of dopaminergic neurons.

We have recently demonstrated that intrathecally injected noradrenaline caused propulsive contractions of the colorectum. We hypothesized that descending pain inhibitory pathways control not only pain, but also the defaecation reflex. Because dopamine is one of the major neurotransmitters of descending pain inhibitory pathways in the spinal cord, we examined the effects of the intrathecal application of dopamine to the spinal defaecation centre on colorectal motility. Colorectal intraluminal pressure and expelled volume were recorded in vivo in anaesthetized rats. Slice patch clamp and immunohistochemistry were used to confirm the existence of dopamine‐sensitive neurons in the sacral parasympathetic nuclei. Intrathecal application of dopamine into the L6–S1 spinal cord, where the lumbosacral defaecation centre is located, caused propulsive contractions of the colorectum. Inactivation of spinal neurons using TTX blocked the effect of dopamine. Although thoracic spinal transection had no effect on the enhancement of colorectal motility by intrathecal dopamine, the severing of the pelvic nerves abolished the enhanced motility. Pharmacological experiments revealed that the effect of dopamine is mediated primarily by D2‐like dopamine receptors. Neurons labelled with retrograde dye injected at the colorectum showed an inward current in response to dopamine in slice patch clamp recordings. Furthermore, immunohistochemical analysis revealed that neurons immunoreactive to choline acetyltransferase express D2‐like dopamine receptors. Taken together, our findings demonstrate that dopamine activates sacral parasympathetic preganglionic neurons via D2‐like dopamine receptors and causes propulsive motility of the colorectum in rats. The present study supports the hypothesis that descending pain inhibitory pathways regulate defaecation reflexes.
Ranking of Creep Damage in Main Steam Piping System Girth Welds Considering Multiaxial Stress Ranges
Authors: Cohn Marvin J. , Faham Fatma G. , Patel Dipak
Published: March 2016

A high-energy piping (HEP) asset integrity management program is important for the safety of plant personnel and reliability of the fossil plant generating unit. HEP weldment failures have resulted in serious injuries, fatalities, extensive damage of components, and significant lost generation. The main steam (MS) piping system is one of the most critical HEP systems. Creep damage assessment in MS piping systems should include the evaluation of multiaxial stresses associated with field conditions and significant anomalies, such as malfunctioning supports and significant displacement interferences. This paper presents empirical data illustrating that the most critical girth welds of MS piping systems have creep failures which can be successfully ranked by a multiaxial stress parameter, such as maximum principal stress. Inelastic (redistributed) stresses at the piping outside diameter (OD) surface were evaluated for the base metal of three MS piping systems at the piping analysis model nodes. The range of piping system stresses at the piping nodes for each piping system was determined for the redistributed creep stress condition. The range of piping stresses was subsequently included on a Larson–Miller parameter (LMP) plot for the grade P22 material, revealing the few critical (lead-the-fleet) girth welds selected for nondestructive examination (NDE). In the three MS piping systems, the stress ranges varied from 55% to 80%, with only a few locations at stresses beyond the 65 percentile of the range. By including evaluations of significant field anomalies and the redistributed multiaxial stresses on the outside surface, it was shown that there is a good correlation of the ranked redistributed multiaxial stresses to the observed creep damage. This process also revealed that a large number of MS piping girth welds have insufficient applied stresses to develop substantial creep damage within the expected unit lifetime (assuming no major fabrication defects). This study also provided a comparison of the results of a conventional American Society of Mechanical Engineers (ASME) B31.1 Code as-designed sustained stress analysis versus the redistributed maximum principal stresses in the as-found (current) condition for a complete set of MS piping system nodes. The evaluations of redistributed maximum principal stresses in the as-found condition were useful in selecting high priority ranked girth weldment creep damage locations. The evaluations of B31.1 Code as-designed sustained load stresses were not useful in selecting high priority creep damage locations.
Design of Nonoverconstrained Energy-Efficient Multi-Axis Servo Presses for Deep-Drawing Applications1
Authors: Meoni Francesco , Carricato Marco
Published: March 2016

Servo-actuated presses may provide maximum pressing force at any ram position in the same manner that hydraulic presses do, while offering several benefits in terms of precision, energy-conversion efficiency, and simplicity, due to their lack of hydraulic circuitry and oil. Several press builders have developed servo-actuated presses; however, issues relating to overconstrained multi-axis architecture have been disregarded. This study proposes an innovative method to avoid overconstrained architectures in multi-axis presses, by implementing a family of modular parallel mechanisms that connect multiple servo-axes to the press ram. Parallel mechanisms, which can be applied in several fields of robotics and industrial automation, exhibit important benefits for the application at hand, including high-load capacity, stiffness, and compactness. A biaxial industrial servo press prototype with a nonoverconstrained and modular architecture was built and presented as a proof of concept. Each axis comprises a servomotor, a gearbox reducer, and a ball-screw transmission. It is shown that such a press may be constructed from commercially available components, achieving high energy efficiency and high press force with relatively simple construction. A direct comparison with an equivalent hydraulic-press model is carried out, thus highlighting the servo press energy efficiency.
Predictive Model Selection for Forecasting Product Returns
Authors: Ma Jungmok , Kim Harrison M.
Published: March 2016

As awareness of environmental issues increases, the pressures from the public and policy makers have forced original equipment manufacturers (OEMs) to consider remanufacturing as the key product design option. In order to make the remanufacturing operations more profitable, forecasting product returns is critical due to the uncertainty in quantity and timing. This paper proposes a predictive model selection algorithm to deal with the uncertainty by identifying a better predictive model. Unlike other major approaches in literature such as distributed lag models or DLMs, the predictive model selection algorithm focuses on the predictive power over new or future returns and extends the set of candidate models. The case study of reusable bottles shows that the proposed algorithm can find a better predictive model than the DLM.
Dynamics of Cross-Flow Heat Exchanger Tubes With Multiple Loose Supports
Authors: Sadath Anwar , Dixit Harish N. , Vyasarayani C. P.
Published: March 2016

Dynamics of cross-flow heat exchanger tubes with two loose supports has been studied. An analytical model of a cantilever beam that includes time-delayed displacement term along with two restrained spring forces has been used to model the flexible tube. The model consists of one loose support placed at the free end of the tube and the other at the midspan of the tube. The critical fluid flow velocity at which the Hopf bifurcation occurs has been obtained after solving a free vibration problem. The beam equation is discretized to five second-order delay differential equations (DDEs) using Galerkin approximation and solved numerically. It has been found that for flow velocity less than the critical flow velocity, the system shows a positive damping leading to a stable response. Beyond the critical velocity, the system becomes unstable, but a further increase in the velocity leads to the formation of a positive damping which stabilizes the system at an amplified oscillatory state. For a sufficiently high flow velocity, the tube impacts on the loose supports and generates complex and chaotic vibrations. The impact loading on the loose support is modeled either as a cubic spring or a trilinear spring. The effect of spring constants and free-gap of the loose support on the dynamics of the tube has been studied.
Development of a Simulation Analysis Environment for Ventilated Slab Systems
Authors: Park Benjamin , Krarti Moncef
Published: March 2016

This paper presents a simulation environment developed to assess the energy performance of hollow core ventilated slab systems. The developed simulation environment combines a transient finite difference solution of a ventilated slab system with an RC network model for a multi-floor building. The developed simulation environment takes into account ventilated slab system thermal bridge effects on the energy performance of multi-floor buildings. The predictions of the developed simulation environment are verified against those obtained from a detailed whole-building energy simulation tool. In addition, several parametric analyses are performed to determine the performance of ventilated slab systems under various design and operating conditions. In particular, the parametric analyses include the effect of supply air inlet temperature, air mass flow rate, hollow core depth, and hollow core diameter. In particular, it is found that due to increased heat transfer through slab edge increases due to thermal bridge effects, ventilated slab requires 5% more heating and 7% more cooling energy end-uses.
General Beam Cross-Section Analysis Using a 3D Finite Element Slice
Authors: Couturier Philippe , Krenk Steen
Published: March 2016

A formulation for analysis of general cross-section properties has been developed. This formulation is based on the stress-strain states in the classic six equilibrium modes of a beam by considering a finite thickness slice modelled by a single layer of 3D finite elements. The displacement variation in the lengthwise direction is in the form of a cubic polynomial, which is here represented by Hermitian interpolation, whereby the degrees of freedom are concentrated on the front and back faces of the slice. The theory is illustrated by application to a simple cross-section for which an analytical solution is available. The paper also shows an application to wind turbine blade cross-sections and discusses the effect of the finite element discretization on the cross-section properties such as stiffness parameters and the location of the elastic and shear centers.
Enhanced Thermal Transport of Nanostructured Phase Change Composite for Thermal Energy Storage
Authors: Sivasankaran Harish , Takata Yasuyuki , Kohno Masamichi
Published: March 2016

The power dissipation capacity of organic phase change materials (PCM) which is used for thermal energy storage applications is hindered by its low thermal conductivity. In this work we demonstrate that inclusion of few layer graphene nanoplatelets dramatically increase the thermal conductivity of the PCM upon solidification. The dramatic thermal conductivity increase stems from the fact that the graphene nanoplatelets are entrapped within the grain boundaries upon solidification of the crystalline structures thereby increasing the percolation pathways. We also show that the enhancement in thermal conductivity is beyond the predictions of effective medium theory. The present work introduces an efficient way to enhance the thermal conductivity of nanocomposites using few layer graphene by effectively controlling the heat transport path simply upon solidification. Such a phase change material with enhanced thermal conductivity makes it a promising candidate for thermal energy storage applications.
Measurement of Local Mass Transfer Distribution in a Large Diameter S-Bend at High Reynolds Number
Authors: Wang D. , Ewing D. , Le T. , Ching C. Y.
Published: March 2016

The local mass transfer in a 203mm diameter back to back bend arranged in a S-configuration was measured at a Reynolds number of 300,000. A dissolving wall method using gypsum dissolution to water at 40°C was used, with a Schmidt number of 660. The experiment was performed in a flow loop by flowing water through the test section. The topography of the unworn and the worn inner surface was quantified using nondestructive X-ray Computed Tomography (CT) scans. The two scanned surfaces were aligned to a common coordinate system using commercial software and in-house routines. The local mass transfer rate was obtained from the local change in radius over the flow time. Two regions of high mass transfer were present: (i) along the intrados of the first bend near the inlet and (ii) at the exit of the extrados of the first bend that extends to the intrados of the second bend. The latter was the region of highest mass transfer in the S-bend.
Exergy-Based Analysis of an Isolated Honduras Community
Authors: Micangeli Andrea , Michelangeli Emanuele , Ricci Marco , Sciubba Enrico
Published: March 2016

Environmental considerations are an essential part of any energy conversion assessment: especially in the analysis of natural reservations and protected areas, the concept of “environmental impact” has substantially evolved in the last decade, from an ex-post “assessment of ecological damage” to a complex, omni-comprehensive, but also pro-active and detailed, examination of the local and global implications of the interactions of anthropic processes with the biosphere. Evermore complete sets of quantitative measures of the interaction, called Environmental Indicators (El), have been developed with the intent of providing a sufficiently accurate and reliable decision support basis for planners and decision makers. There are though some intrinsic problems about this approach, more acutely felt in the analysis of natural systems: on the one hand, generality conflicts with specificity, and it is often difficult to connect a local El with a more global measure of environmental impact; on the other hand, several of the proposed Els are not completely satisfactory because they lack of a sound physical basis. Extended Exergy is an indicator that seems to overcome the above limitations: it is firmly rooted in thermodynamic principles and is articulated in such a way as to constitute a reliable quantitative measure of the total amount of primary resources consumed in a given conversion chain. The indicator is derived from a quite complex bookkeeping of the exergy fluxes of the system it is applied to, and makes use of two econometric coefficients for this quantification, which are external to the theory and must be calculated on the basis of proper labour and monetary statistics. In this paper, the method is applied to a community in northern Honduras, which is sufficiently remote and ill-connected with the rest of the Country to be considered in practice as an isolated system. The application of the Extended Exergy Accounting method to such a system constitutes an important benchmark, because the Labour fluxes are much more easily measured and the monetary circulation exerts a negligible influence on the evolution of the system.
Design and Prototyping of a Cost-Effective Sun Tracking System for Photovoltaic Panels
Authors: Georgescu Adrian , Simionescu P. A. , Tălpăşanu Ilie
Published: March 2016

The paper discusses the design and prototype build of a sun tracking system for photovoltaic panels, that consists of a slider-rocker mechanism and a controls system. The slider-rocker is optimized for best transmission angle properties, near linear input-output function and 180 degrees rocker travel. The control system includes three shaded light-dependent resistors pointing in different directions, and operational amplifiers to sense the imbalance in their illumination. The amplified imbalanced signal is used to control the linear motor of the slider-rocker mechanism towards minimizing this imbalance. A small scale prototype of the system has been built and tested successfully.
Evaluation of Passive Anti-Fouling Technology Applied to CO2 Heat Pump Water Heaters
Authors: Murray Portia , Harrison Stephen J. , Stinson Ben
Published: March 2016

Heat pump water heaters are increasing in popularity due to their increased energy efficiency and low environmental impact. This paper describes the experimental testing of a transcritical CO2 heat pump water heater at Queen’s University.

A modified 4.5 kW Eco-Cute unit was studied. It sourced heat from a constant temperature water supply and rejected the heat to a 273 litre hot water tank through a gas-cooler. The high temperatures that occur in the gas-cooler of this unit make it ideally suited for natural convection, (i.e., thermosyphon) circulation on the potable water side. This has the potential to reduce pumping power, simplify system operation and design, and increase thermal stratification in the hot water storage tank.

This configuration, however, is susceptible to the accumulation of sediments, scale and mineral deposits (i.e., fouling) in geographic regions where high mineral deposits may be present in the water supply. To counteract fouling in these cases, a passive back-flushing system was proposed to prevent the accumulation of deposits on the heat transfer surfaces of the gas-cooler. As hot water is drawn from the system, the cold “mains” supply water is directed through the gas-cooler in the reverse direction of normal operation, scouring the heat transfer surfaces and dissolving deposits of inverse-soluble salts which are a major contributor to fouling on hot heat transfer surfaces.

The gas-cooler used was a specially designed unit that, although offering high performance in a compact unit, may be susceptible to the fouling and blockage of the heat transfer passages when used at thermosyphon flow rates.

Experiments were conducted to evaluate the effects of the back-flush operation on heat pump performance (i.e., COP) and operation. These were conducted under controlled laboratory conditions, at a range of draw flow rates and temperatures, and are summarized in this paper.
Optical Analyses of Microfluidic Tunable Liquid Prisms for Enhanced Solar Energy Collection
Authors: Wadhwa Abhishek , Park Sung-Yong
Published: March 2016

We present optical analyses of a microfluidic tunable liquid prism to find its optimized configuration that can achieve wider beam steering as well as less reflection loss and eventually maximize solar energy capture without mechanical tracking. For this study, four different prism configurations are compared from single to quad-stacked ones with various refractive indices of the liquids filled in the prism. Its beam steering capability can be improved by increasing the refractive index ratio between the liquids used and by using higher number of the stacked prisms. The quad-stacked prism is able to steer incoming sunlight with an incident angle of a α ≤ ± 75° at an apex angle of φ ≤ ± 30°, which represents more than 5 times improvement, when it is compared to the single prism using the same liquids. For appropriate liquid material selection, the effect of refractive index ratio, r = n2/n1, on beam steering was additionally studied. However, one considerable issue is the fact that the better beam steering, the more reflection loss. This is because both higher number of interfaces and larger refractive index ratio make more reflection at each of the interfaces. Our reflectance analysis showed that the quad prism performs inferior to the double prism until α = ± 32°, while being of superior beam steering performance. To further reduce the solar energy loss through the quad prism, a modified configuration is proposed with a thin film added to the interfaces. 50 % of the total reflection was reduced. Our technology promises an alternative to a low-cost and high-efficiency solar tracking system capable of beam steering as wide as ± 75° and reflection loss as low as 4.5%, during all daily tracking of the sun.
Combined Cycle Power Plant Thermo-Economic Multi-Objective Optimization Using Evolutionary Algorithm
Authors: Canepa Roberto , Croce Giulio , Zunino Pietro
Published: March 2016

In this paper, an integrated modeling framework consisting of GateCycle® power plant modeling commercial software, an evolutionary based optimization tool and an in-house developed computer code suitable for thermo-economic calculations, has been applied to the optimization of the bottoming steam cycle of an advanced combined cycle power plant. Out of the many economic performance evaluation parameters available, optimal performance have been obtained under both Net Present Value (NPV) maximization and Levelized Cost Of Electricity (LCOE) minimization.

A basic superstructure, capable to handle multiple configurations such as HRSG arrangements, as well as pressure levels number, has been developed within the proposed modeling framework. The optimization tool handles simultaneously a large number of variables, both thermo-economic (for instance the suitable temperature differences and the pressure levels) and logical, defining the HRSG configuration.

While many on-site (boundary) conditions affect optimal design, fuel gas cost is securely the most relevant parameter affecting thermo-economic performance during power plant lifetime. Therefore, optimal performance, that is maximum NPV and minimum LCOE, has been obtained assuming different values for this parameter.

It has been proven how the framework is able to cope with varying on-site conditions and how, when these latter are carefully taken into account, optimal design is even significantly modified.
Development and Field Testing of an Inclined Flanged Compact Diffuser for a Micro Wind Turbine
Authors: Kale Sandip , Sapali S. N.
Published: March 2016

Micro wind turbines installed in various applications, experience average wind speed for most of the time during operations. Power produced by the wind turbine is proportional to the cubic power of the wind velocity and a small increase in wind velocity results increases power output significantly. The approach wind velocity can be increased by covering traditional wind turbine with a diffuser. Researchers are continuously working to develop a compact, lightweight, cost effective and feasible diffuser for wind turbines. The present work carried out to develop a diffuser with these stated objectives. A compact, lightweight inclined flanged diffuser developed for a micro wind turbine. Bare micro wind turbine and wind turbine covered with developed efficient inclined flanged diffuser tested in the field as per International Electrotechnical Commission (IEC) standards and results presented in the form of power curves. The prediction of annual energy production for both wind turbines determined as per IEC standards.
Large Eddy Simulation of Single-Sided Ventilated Room With Different Location of Windows
Authors: Idris A. , Huynh B. P.
Published: March 2016

The natural ventilation contributes the improvement of internal thermal comfort and internal air quality when applied properly. An investigation of single-sided double opening was performed to a 3-dimensional rectangular-box room using a commercial Computational Fluid Dynamics (CFD) software package of ESI group. Sixteen models with different location of double-openings were investigated. The large eddy simulation (LES) turbulence model was used to predict the air’s flow rate and air flow pattern. The governing equations for large eddy motion was obtained by filtering the Navier-Stokes and continuity equations. From the overall results, the lowest and the highest air flow rates were obtained to be 1.14 × 10−3 m3/s and 2.12 × 100 m3/s respectively. The location & arrangement of opening influences the air flow rate and air flow pattern.