bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of different standard red blood cell storage temperatures on human and canine RBC hemolysis and chromium survival
Authors: Blaine Kevin P. , Cortés‐Puch Irene , Sun Junfeng , Wang Dong , Solomon Steven B. , Feng Jing , Gladwin Mark T. , Kim‐Shapiro Daniel B. , Basu Swati , Perlegas Andreas , West Kamille , Klein Harvey G. , Natanson Charles
Published: November 2018

BACKGROUND

Storage temperature is a critical factor for maintaining red‐blood cell (RBC) viability, especially during prolonged cold storage. The target range of 1 to 6°C was established decades ago and may no longer be optimal for current blood‐banking practices.

STUDY DESIGN AND METHODS

Human and canine RBCs were collected under standard conditions and stored in precision‐controlled refrigerators at 2°C, 4°C, or 6°C.

RESULTS

During 42‐day storage, human and canine RBCs showed progressive increases in supernatant non–transferrin‐bound iron, cell‐free hemoglobin, base deficit, and lactate levels that were overall greater at 6°C and 4°C than at 2°C. Animals transfused with 7‐day‐old RBCs had similar plasma cell‐free hemoglobin and non–transferrin‐bound iron levels at 1 to 72 hours for all three temperature conditions by chromium‐51 recovery analysis. However, animals transfused with 35‐day‐old RBCs stored at higher temperatures developed plasma elevations in non–transferrin‐bound iron and cell‐free hemoglobin at 24 and 72 hours. Despite apparent impaired 35‐day storage at 4°C and 6°C compared to 2°C, posttransfusion chromium‐51 recovery at 24 hours was superior at higher temperatures. This finding was confounded by a preparation artifact related to an interaction between temperature and storage duration that leads to removal of fragile cells with repeated washing of the radiolabeled RBC test sample and renders the test sample unrepresentative of the stored unit.

CONCLUSIONS

RBCs stored at the lower bounds of the temperature range are less metabolically active and produce less anaerobic acidosis and hemolysis, leading to a more suitable transfusion product. The higher refrigeration temperatures are not optimal during extended RBC storage and may confound chromium viability studies.
Use of an aiming device and computed tomography for assisted debridement of subchondral cystic lesions in the limbs of horses
Authors: Jackson Michelle A. , Ohlerth Stefanie , Fürst Anton E.
Published: November 2018

Objective

To describe the use of an aiming device (AD) and computed tomography (CT) for preoperative planning and intraoperative guided debridement of subchondral cystic lesions (SCL) in the limbs of horses and to determine the outcome 12 months after surgery.

Study design

Prospective case series.

Animals

Twelve horses referred because of lameness caused by 1 or 2 SCL (total of 14 SCL).

Methods

All horses underwent CT‐guided debridement of the SCL. The entry point of the drill bit and direction of drilling were planned and controlled by using a series of CT images and the AD. The SCL were curetted and filled with recombinant human bone morphogenetic protein‐2. Surgical times were calculated, and the outcome was determined 12 months after surgery.

Results

The use of an AD and CT allowed precise and straightforward drilling of the SCL. The entry point of the drill bit into the SCL was considered optimal in 11 SCL and satisfactory in 3 SCL, and the lesions could be precisely debrided with preservation of the adjacent subchondral bone in all cases. There were no complications. Mean (range) surgery time was 75 (45–115) minutes. The outcome 12 months postoperatively was favorable in 10 of 11 horses. One horse died due to unrelated reasons.

Conclusion

The use of CT and an AD allowed precise debridement of all SCL in the limbs of 12 horses.

Clinical significance

CT‐guided surgical debridement of SCL of the equine digit appears to result in a favorable outcome.
SIRT1 overexpression attenuates offspring metabolic and liver disorders as a result of maternal high‐fat feeding
Authors: Nguyen Long T. , Chen Hui , Zaky Amgad , Pollock Carol , Saad Sonia
Published: November 2018

Key points

Maternal high‐fat diet (MHF) consumption led to metabolic and liver disorders in male offspring, which are associated with reduced sirtuin (SIRT)1 expression and activity in the offspring liver

SIRT1 overexpression in MHF offspring reduced their body weight and adiposity and normalized lipid metabolic markers in epididymal and retroperitoneal adipose tissues

SIRT1 overexpression in MHF offspring improved glucose tolerance, as well as systemic and hepatic insulin sensitivity

SIRT1 overexpression ameliorated MHF‐induced lipogenesis, oxidative stress and fibrogenesis in the liver of offspring.

Maternal obesity can increase the risk of metabolic disorders in the offspring. However, the underlying mechanism responsible for this is not clearly understood. Previous evidence implied that sirtuin (SIRT)1, a potent regulator of energy metabolism and stress responses, may play an important role. In the present study, we have shown, in C57BL/6 mice, that maternal high‐fat diet (HFD) consumption can induce a pre‐diabetic and non‐alcoholic fatty liver disease phenotype in the offspring, associated with reduced SIRT1 expression in the hypothalamus, white adipose tissues (WAT) and liver. Importantly, the overexpression of SIRT1 in these offspring significantly attenuated the excessive accumulation of epididymal (Epi) white adipose tissue (WAT) and retroperitoneal (Rp)WAT (P < 0.001), glucose intolerance and insulin resistance (both P < 0.05) at weaning age. These changes were associated with the suppression of peroxisome proliferator‐activated receptor gamma (PPAR)γ (P < 0.01), PPARγ‐coactivator 1‐alpha (P < 0.05) and sterol regulatory element‐binding protein‐1c in EpiWAT (P < 0.01), whereas there was increased expression of PPARγ in RpWAT (P < 0.05). In the liver, PPARγ mRNA expression, as well as Akt protein expression and activity, were increased (P < 0.05), whereas fatty acid synthase and carbohydrate response element binding protein were downregulated (P < 0.05), supporting increased insulin sensitivity and reduced lipogenesis in the liver. In addition, hepatic expression of endogenous anti‐oxidants, including glutathione peroxidase 1 and catalase, was increased (P < 0.01 and P < 0.05 respectively), whereas collagen and fibronectin deposition was suppressed (P < 0.01). Collectively, the present study provides direct evidence of the mechanistic significance of SIRT1 in maternal HFD‐induced metabolic dysfunction in offspring and suggests that SIRT1 is a promising target for fetal reprogramming.
ORAI1 channel gating and selectivity is differentially altered by natural mutations in the first or third transmembrane domain
Authors: Bulla M. , Gyimesi G. , Kim J.H. , Bhardwaj R. , Hediger M.A. , Frieden M. , Demaurex N.
Published: November 2018

Key points

Gain‐of‐function mutations in the highly selective Ca2+ channel ORAI1 cause tubular aggregate myopathy (TAM) characterized by muscular pain, weakness and cramping.

TAM‐associated mutations in ORAI1 first and third transmembrane domain facilitate channel opening by STIM1, causing constitutive Ca2+ influx and increasing the currents evoked by Ca2+ store depletion.

Mutation V107M additionally decreases the channel selectivity for Ca2+ ions and its inhibition by acidic pH, while mutation T184M does not alter the channel sensitivity to pH or to reactive oxygen species.

The ORAI blocker GSK‐7975A prevents the constitutive activity of TAM‐associated channels and might be used in therapy for patients suffering from TAM.

Skeletal muscle differentiation relies on store‐operated Ca2+ entry (SOCE) mediated by STIM proteins linking the depletion of endoplasmic/sarcoplasmic reticulum Ca2+ stores to the activation of membrane Ca2+‐permeable ORAI channels. Gain‐of‐function mutations in STIM1 or ORAI1 isoforms cause tubular aggregate myopathy (TAM), a skeletal muscle disorder with muscular pain, weakness and cramping. Here, we characterize two overactive ORAI1 mutants from patients with TAM: V107M and T184M, located in the first and third transmembrane domain of the channel. When ectopically expressed in HEK‐293T cells or human primary myoblasts, the mutated channels increased basal and store‐operated Ca2+ entry. The constitutive activity of V107M, L138F, T184M and P245L mutants was prevented by low concentrations of GSK‐7975A while the G98S mutant was resistant to inhibition. Electrophysiological recordings confirmed ORAI1‐V107M constitutive activity and revealed larger STIM1‐gated V107M‐ and T184M‐mediated currents with conserved fast and slow Ca2+‐dependent inactivation. Mutation V107M altered the channel selectivity for Ca2+ ions and conferred resistance to acidic inhibition. Ca2+ imaging and molecular dynamics simulations showed a preserved sensitivity of T184M to the negative regulation by reactive oxygen species. Both mutants were able to mediate SOCE in Stim1−/−/Stim2−/− mouse embryonic fibroblasts expressing the binding‐deficient STIM1‐F394H mutant, indicating a higher sensitivity for STIM1‐mediated gating, with ORAI1‐T184M gain‐of‐function being strictly dependent on STIM1. These findings provide new insights into the permeation and regulatory properties of ORAI1 mutants that might translate into therapies against diseases with gain‐of‐function mutations in ORAI1.
Explicaciones causales en la investigación cualitativa: elección escolar en Chile
Authors: Barco Blanca , Carrasco Alejandro
Published: November 2018

Este artículo reflexiona sobre cómo las investigaciones cualitativas en educación pueden generar explicaciones causales. Para ello, se propone analizar el concepto de causalidad y su posicionamiento en los paradigmas positivista e interpretativo. Luego, se profundizará en las estrategias y los análisis que posibilitan la generación de mecanismos contextualizados y conceptualizados. Además, utilizando una investigación cualitativa sobre elección escolar, se ejemplificará la generación de mecanismos y explicaciones causales en sus resultados. Finalmente, este artículo concluye sobre el aporte del realismo crítico en las investigaciones cualitativas, en especial en educación, para generar explicaciones causales.
Epistemología y experiencia en Freire. Contribuciones a una metodología narrativa
Authors: Cavieres-Fernández Eduardo Andrés
Published: November 2018

El presente trabajo contribuye con perspectivas fundamentales para el desarrollo de una metodología narrativa en esta parte del continente. La importancia de aquello radica, a su vez, en que esa metodología ofrece un conocimiento alternativo al provisto por investigaciones positivistas cuantitativas que al generalizar sus resultados buscan estandarizar el quehacer de los docentes. En coherencia con el pensamiento de Paulo Freire, construido sobre las experiencias de los profesores, la metodología narrativa en cambio posibilita un conocimiento contextualizado del profesor que ayuda a comprender mejor su tarea en favor del educando y que debe desarrollarse en un contexto particular latinoamericano.
Expanding Educational Leadership Theories through Qualitative Relational Methodologies
Authors: Smit Brigitte
Published: November 2018

Educational leadership is conceptualised through a relational framework and empirically understood through qualitative relational methodologies such as relational ethics, ethics of care and narrative inquiry. Empirical data from narrative interviews revealed that in many cases where the school principals honed values such as care and relational attributes in their daily leadership practices, learners were more likely to respond to such relational and caring practices, which they witnessed and experienced. It appears that relational methodologies can elicit relational leadership styles, which set caring and supportive examples for both teachers and learners, adding much worth to a favourable educational landscape.
Resisting the Drive to Theorise: A Phenomenological Perspective on Social Science Research
Authors: Williams Emma
Published: November 2018

This article explores predominant uses of theory in social science research in relation to the approach of phenomenological philosophy. While phenomenology is sometimes interpreted as one theoretical or methodological paradigm amongst others in the field of qualitative research, this article explores key thinkers within the philosophical tradition of phenomenology to argue that this tradition can raise challenges for predominant conceptions of research and theorizing in the social sciences and certain philosophical idea(l)s that can be connected to them. The distinctive nature of phenomenological description is outlined, and new possibilities for qualitative research are sketched.
“Tu enfoque determina tu realidad”: una vida dedicada a unir teoría y práctica en la investigación cualitativa
Authors: Barba-Martín Raúl Alberto , Gómez-González Aitor , González-Calvo Gustavo
Published: November 2018

La dicotomía teoría-práctica ha sido uno de los debates que han marcado el desarrollo de la investigación cualitativa. Desde diferentes enfoques se ha abordado el cómo poder unir praxis y teoría, y les ha dado voz a los participantes en los procesos de investigación. En este artículo, vamos a abordar las principales contribuciones de José Juan Barba Martín, marcadas todas ellas por la necesidad de transformar la educación. Esta perspectiva transformadora, basada en los referentes de la teoría crítica, le permitió desarrollar investigaciones dirigidas a transformar la realidad social y educativa, y aunar teoría y práctica durante el proceso investigador.
Understanding the Categories and their Natural Properties
Authors: Scott David
Published: November 2018

There are four ways of distinguishing theories or models about categories such as quantity, race and dis-ability and the relationship between mind and world. (i) Epistemic: a theory is superior to another because it has a better relationship with the world. (ii) The converse: a version of reality is superior to another because it contains fewer contradictions and disjunctions. (iii) The giving of reasons: some reasons and systems of rationality are superior to others. (iv) Pragmatic: a theory is better than another because it is more practically adequate. I suggest that a combination of all four reasons is appropriate.
Start-Up Optimization of a CCGT Power Station Using Model-Based Gas Turbine Control
Authors: Nannarone Alessandro , Klein Sikke A.
Published: November 2018

The rapid growth of renewable generation and its intermittent nature has modified the role of combined cycle power stations in the energy industry, and the key feature for the operational excellence is now flexibility. Especially, the capability to start an installation quickly and efficiently after a shutdown period leads to lower operational cost and a higher capacity factor. However, most of existing thermal power stations worldwide are designed for continuous operation, with no special focus on an efficient start-up process. In most current start-up procedures, the gas turbine controls ensure maximum heat flow to the heat recovery steam generator, without feedback from the steam cycle. The steam cycle start-up controls work independently with as main control parameter the limitation of the thermal stresses in the steam turbine rotor. In this paper, a novel start-up procedure of an existing combined cycle power station is presented, and it uses a feedback loop between the steam turbine, the boiler and the gas turbine start-up controls. This feedback loop ensures that the steam turbine can be started up with a significant reduction in stresses. To devise and assess this start-up methodology, a flexible and accurate dynamic model was implemented in the Simulink environment. It contains >100 component blocks (heat exchangers, valves, meters and sensors, turbines, controls, etc.), and the mathematical component submodels are based on physical models and experimental correlations. This makes the model generally applicable to other power plant installations. The model was validated against process data related to the three start-up types (cold start, warm start, hot start). On this basis, the optimization model is implemented with feedback loops that control, for example, the exit temperature of the gas turbine based on the actual steam turbine housing temperature, resulting in a smoother heating up of the steam turbine. The optimization model was used to define the optimal inlet guide vanes position and gas turbine power output curves for the three types of start-up. These curves were used during real power station start-ups, leading to, for cold and warm starts, reductions in the start-up time of, respectively, 32.5% and 31.8%, and reductions in the fuel consumption of, respectively, 47.0% and 32.4%. A reduction of the thermal stress in the steam turbines is also achieved, thanks to the new start-up strategy.
Wide Range Measurement of Lubricant Film Thickness Based on Ultrasonic Reflection Coefficient Phase Spectrum
Authors: Dou Pan , Wu Tonghai , Luo Zhaopeng
Published: November 2018

The ultrasonic technique is very effective in measuring lubricant film thickness in a noninvasive manner. To estimate the film thickness with reflection signals, two main ultrasonic models are often applied in cases of different film thicknesses; they are the spring model for thin films and the resonant model for thick films. However, when measuring oil film thicknesses distributed in a wide range, there is an inherent blind zone between these two models. This problem is especially prominent in online monitoring because the abrupt variation of film thickness is highly correlated with the occurrence of abnormal conditions. To address this issue, we further proposed a method using the phase spectrum of reflection coefficient which can cover a wide range of film thicknesses. The slight variation of reflection signal in the blind zone can then be identified and bridged the measurement gap between those two traditional models. A calibration rig was used to verify the theoretical analysis and the results indicated that the developed model is capable of providing reliable ultrasonic measurement of lubricant film thicknesses in a wide range.
A Note on Model Selection Based on the Percentage of Accuracy-Precision
Authors: Heidaryan Ehsan
Published: November 2018

Mathematical methods such as empirical correlations, analytical models, numerical simulations, and data-intensive computing (data-driven models) are the key to the modeling of energy science and engineering. Accrediting of different models and deciding on the best method, however, is a serious challenge even for experts, as the application of models is not limited only to estimations, but to predictions and derivative properties. In this note, by combining meaningful metrics of accuracy and precision, a new metric for determining the best-in-class method was defined.
Dependent Competing Risks Modeling for Mechanical Systems Under Component and Performance Failure
Authors: Liu Jingyi , Zhang Yugang , Song Bifeng
Published: November 2018

This paper establishes a competing failure analysis model for complex mechanical system under component failure and performance failure considering degradation. Traditionally, mechanical system is composed by a number of components. Meanwhile, mechanical system has the ability to accomplish its specific performance. Therefore, mechanism may fail because of two kinds of failure modes, the component failure due to degradation (such as component wear) and the performance failure (system couldn't complete performance). The two failure modes compete with each other because as soon as one mode occurs the system just fails. The component will degrade with time as system operates as well as the system performance. In this paper, Brownian motion (BM) with nonlinear drift is used to model the degradation of components based on which component failure is analyzed. The function of performance measurement is built by surrogate and performance failure is analyzed by it at different working circulation. Farlie–Gumbel–Morgenstern (FGM) copula is introduced to describe the dependence. The system reliability is analyzed by FGM copula as well as competing failure probability for each failure mode. Finally, a numerical example and an engineering case study are used to illustrate the proposed model.
A Lyapunov Stable Controller for Bilateral Haptic Teleoperation of Single-Rod Hydraulic Actuators Subjected to Base Disturbance
Authors: Banthia Vikram , Maddahi Ali , Zareinia Kourosh , Balakrishnan Subramaniam , Sepehri Nariman
Published: November 2018

In this paper, a control scheme is developed and evaluated for stable bilateral haptic teleoperation of a single-rod hydraulic actuator subjected to base disturbance. The proposed controller, based on Lyapunov stability technique, is capable of reducing position errors at master and slave sides, and provides a feel of the contact force between the actuator and the task environment to the operator without a need for direct measurement. The controller requires only the measurements of the actuator line pressures and displacements of the master and slave. The system stability is insensitive to the uncertainties of the physical parameters and of the measurement of the base point motion. Stability of the proposed controller incorporating hydraulic nonlinearities and operator dynamics with an estimated upper value for the base disturbance is analytically proven. Simulation studies validate that the proposed control system is stable while interacting with a task environment. Experimental results demonstrate the effectiveness of control scheme in maintaining stability, while having good position tracking by the hydraulic actuator as well as providing a haptic feel to the operator without direct measurement of interaction force, while the hydraulic actuator is subjected to base disturbance.
Interpreting Idea Maps: Pairwise Comparisons Reveal What Makes Ideas Novel
Authors: Ahmed Faez , Ramachandran Sharath Kumar , Fuge Mark , Hunter Samuel , Miller Scarlett
Published: November 2018

Assessing similarity between design ideas is an inherent part of many design evaluations to measure novelty. In such evaluation tasks, humans excel at making mental connections among diverse knowledge sets to score ideas on their uniqueness. However, their decisions about novelty are often subjective and difficult to explain. In this paper, we demonstrate a way to uncover human judgment of design idea similarity using two-dimensional (2D) idea maps. We derive these maps by asking participants for simple similarity comparisons of the form “Is idea A more similar to idea B or to idea C?” We show that these maps give insight into the relationships between ideas and help understand the design domain. We also propose that novel ideas can be identified by finding outliers on these idea maps. To demonstrate our method, we conduct experimental evaluations on two datasets—colored polygons (known answer) and milk frother sketches (unknown answer). We show that idea maps shed light on factors considered by participants in judging idea similarity and the maps are robust to noisy ratings. We also compare physical maps made by participants on a white-board to their computationally generated idea maps to compare how people think about spatial arrangement of design items. This method provides a new direction of research into deriving ground truth novelty metrics by combining human judgments and computational methods.
Studying a Hybrid System Based on Solid Oxide Fuel Cell Combined With an Air Source Heat Pump and With a Novel Heat Recovery
Authors: Vialetto Giulio , Noro Marco , Rokni Masoud
Published: November 2018

In this paper, a new heat recovery for a microcogeneration system based on solid oxide fuel cell and air source heat pump (HP) is presented with the main goal of improving efficiency on energy conversion for a residential building. The novelty of the research work is that exhaust gases after the fuel cell are first used to heat water for heating/domestic water and then mixed with the external air to feed the evaporator of the HP with the aim of increasing energy efficiency of the latter. This system configuration decreases the possibility of freezing of the evaporator as well, which is one of the drawbacks for air source HP in Nordic climates. A parametric analysis of the system is developed by performing simulations varying the external air temperature, air humidity, and fuel cell nominal power. Coefficient of performance (COP) can increase more than 100% when fuel cell electric power is close to its nominal (50 kW), and/or inlet air has a high relative humidity (RH) (close to 100%). Instead, the effect of mixing the exhausted gases with air may be negative (up to −25%) when fuel cell electric power is 20 kW and inlet air has 25% RH. Thermodynamic analysis is carried out to prove energy advantage of such a solution with respect to a traditional one, resulting to be between 39% and 44% in terms of primary energy. The results show that the performance of the air source HP increases considerably during cold season for climates with high RH and for users with high electric power demand.
Backward-Inclined Diffusion Jet Flames in Crossflow at Low Jet-to-Crossflow Momentum Flux Ratios
Authors: Mosiria Dickson Bwana , Huang Rong Fung , Hsu Ching Min
Published: November 2018

In the design of gas turbine combustors, efforts are engineered toward reducing the combustion pollutant emission levels. The pollutant emissions can be reduced by premixing the fuel and the air prior to ignition. However, the main challenges encountered with premixing are flame flashback and blowout, thus, the preference of diffusion flames. In this study, flame behavior, flow patterns, and thermochemical fields of backward-inclined diffusion jet flames in crossflow at low jet-to-crossflow momentum flux ratio of smaller than 0.04 were studied in a wind tunnel. The backward-inclination angle was varied within 0–50 deg. The flames presented three characteristic modes: crossflow dominated flame (low backward inclination angle) denoted by a large down-washed recirculation flame, transitional flame (mediate backward inclination angle) identified by a recirculation flame and a tail flame, and jet dominated flame (high backward inclination angle) characterized by a blue flame base, a yellow tail flame, and the absence of a recirculation flame. Short flames are detected in the regime of the crossflow dominated flames—an indication of improved fuel–air mixing. The findings suggest that for low exhaust emissions which are vigorously pursued in the aviation and thermal power plant industries, especially during low-load operations, the jet dominated flames are the preferable flames as they generate low unburned hydrocarbon, carbon monoxide, and nitric oxide emissions compared to the other flames.
Modeling and Control of Combustion Phasing in Dual-Fuel Compression Ignition Engines
Authors: Sui Wenbo , Pulpeiro González Jorge , Hall Carrie M.
Published: November 2018

Dual-fuel engines can achieve high efficiencies and low emissions but also can encounter high cylinder-to-cylinder variations on multicylinder engines. In order to avoid these variations, they require a more complex method for combustion phasing control such as model-based control. Since the combustion process in these engines is complex, typical models of the system are complex as well and there is a need for simpler, computationally efficient, control-oriented models of the dual-fuel combustion process. In this paper, a mean-value combustion phasing model is designed and calibrated, and two control strategies are proposed. Combustion phasing is predicted using a knock integral model (KIM), burn duration (BD) model, and a Wiebe function, and this model is used in both an adaptive closed loop controller and an open loop controller. These two control methodologies are tested and compared in simulations. Both control strategies are able to reach steady-state in five cycles after a transient and have steady-state errors in CA50 that are less than ±0.1 CA deg (CAD) with the adaptive control strategy and less than ±1.5 CAD with the model-based feedforward control method.
On Mechanical Properties of Cellular Steel Solids With Shell-Like Periodic Architectures Fabricated by Selective Laser Sintering
Authors: Al-Ketan Oraib , Rowshan Reza , Palazotto Anthony N. , Abu Al-Rub Rashid K.
Published: November 2018

Historically, the approach in material selection was to find the proper material that serves a specific application. Recently, a new approach is implemented such that materials are being architected and topologically tailored to deliver a specific functionality. Periodic cellular materials are increasingly gaining interest due to their tunable structure-related properties. However, the concept of structure–property relationship is not fully employed due to limitations in manufacturing capabilities. Nowadays, additive manufacturing (AM) techniques are facilitating the fabrication of complex structures with high control over the topology. In this work, the mechanical properties of additively manufactured periodic metallic cellular materials are investigated. The presented cellular materials comprise a shell-like topology based on the mathematically known triply periodic minimal surfaces (TPMS). Maraging steel samples with different topologies and relative densities have been fabricated using the powder bed fusion selective laser sintering (SLS) technique, and three-dimensional printing quality was assessed by means of electron microscopy. Samples were tested in compression and the compressive mechanical properties have been deduced. Effects of changing layer thickness and postprocessing such as heat treatment are discussed. Results showed that the diamond TPMS lattice has shown superior mechanical properties among the examined topologies.
Heat Transfer Enhancement by Sinusoidal Motion of a Water-Based Nanofluid
Authors: Guler Omer F. , Guven Oguz , Aktas Murat K.
Published: November 2018

The oscillatory flows are often utilized in order to augment heat transfer rates in various industrial processes. It is also a well-known fact that nanofluids provide significant enhancement in heat transfer at certain conditions. In this research, heat transfer in an oscillatory pipe flow of both water and water–alumina nanofluid was studied experimentally under low frequency regime laminar flow conditions. The experimental apparatus consists of a capillary tube bundle connecting two reservoirs, which are placed at the top and the bottom ends of the capillary tube bundle. The upper reservoir is filled with the hot fluid while the lower reservoir and the capillary tube bundle are filled with the cold fluid. The oscillatory flow in the tube bundle is driven by the periodic vibrations of a surface mounted on the bottom end of the cold reservoir. The effects of the frequency and the maximum displacement amplitude of the vibrations on thermal convection were quantified based on the measured temperature and acceleration data. It is found that the instantaneous heat transfer rate between de-ionized (DI) water (or the nanofluid)-filled reservoirs is proportional to the exciter displacement. Significantly reduced maximum heat transfer rates and effective thermal diffusivities are obtained for larger capillary tubes. The nanofluid utilized oscillation control heat transport tubes achieve high heat transfer rates. However, heat transfer effectiveness of such systems is relatively lower compared to DI water filled tubes.
Comprehensive Study on the Effect of CuO Nano Fluids Prepared Using One-Step Chemical Synthesis Method on the Behavior of Waste Cooking Oil Biodiesel in Compression Ignition Engine
Authors: Velmurugan Ramanathan , Mayakrishnan Jaikumar , Induja S. , Raja Selvakumar , Nandagopal Sasikumar , Sathyamurthy Ravishankar
Published: November 2018

Vegetable oil is considered as one among the promising alternatives for diesel fuel as it holds properties very close to diesel fuel. However, straight usage of vegetable oil in compression ignition (CI) engine resulted in inferior performance and emission behavior. This can be improved by modifying the straight vegetable oil into its esters, emulsion, and using them as a fuel in CI engine showcased an improved engine behavior. Waste cooking oil (WCO) is one such kind of vegetable oil gained a lot of attraction globally as it is generated in a large quantity locally. The present investigation aims at analyzing various parameters of single cylinder four stroke CI engine fueled with waste cooking oil biodiesel (WCOB), waste cooking oil biodiesel water emulsion (WCOBE) while the engine is operated with a constant speed of 1500 rpm. Furthermore, an attempt is made to study the impact of nanofluids in the behavior of the engine fueled with WCOB blended with nanofluids (WCOBN50). This work also explored a novel method of producing nanofluids using one-step chemical synthesis method. Copper oxide (CuO) nanofluids were prepared by the above mentioned method and blended with waste cooking oil biodiesel (WCOBN50) using ethylene glycol as a suitable emulsifier. Results revealed that brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) of WCOBN50 are significantly improved when compared to WCOB and WCOBE. Furthermore, a higher reduction in oxides of nitrogen (NOx), carbon monoxide (CO), hydrocarbon (HC), and smoke emissions were observed with WCOBN50 on comparison with all other tested fuels at different power outputs. It is also identified that one-step chemical synthesis method is a promising technique for preparing nanofluids with a high range of stability.
Heat Characteristics Analysis of Electro-Hydraulic Servo Valve
Authors: Zhu Yannan , Zhang Qiang , Tao Jianfeng , Tan Dun , Wang Xuyong
Published: November 2018

A new method of building electro-hydraulic servo valve's thermal model is proposed. In this method, energy conservation equation of servo valve was obtained according to thermodynamics, which describes servo valve's heat conduction, heat convection, and heat radiation with other hydraulic components. Servo valve's thermal model and thermal characteristics model were built and simulated in amesim. Experiment was carried out in four working pressures ranging from 3 MPa to 12 MPa. Simulation and experimental results indicate that servo valve reaches thermal equilibrium in less than 2.5 h, and with pressure's increase, valve reaches thermal equilibrium more quickly with a higher steady temperature. Maximum and steady temperature error between simulation and experimental results are approximately 4.6 °C and 1.5 °C, and when lowering pressure, they both reduce. The temperature error can mainly result from motor's heat production in experiment, which will vanish when the whole hydraulic motor servo system is modeled. Therefore, experimental results verified the validity of valve's thermal characteristics model. The significance of this study is to provide a theoretical basis for subsequent researches of heat characteristics of other hydraulic components, which include hydraulic motor, valve block, hydraulic oil source, and so on.
Effects of Pin-Fin Shapes on Mesh-Fed Slot Film Cooling for a Flat-Plate Model
Authors: Tan Xiao-Ming , Zhang Jing-Zhou , Cai Qing-Zhi
Published: November 2018

Experimental and numerical research is performed to illustrate the effects of pin-fin shapes on mesh-fed slot film cooling performance on a flat-plate model. Three types of pin-fin shapes (such as circular, elliptical, and drop-shaped) with the same cross-sectional area are taken into consideration. The results show that a pair of counter rotating vortices is still generated for the mesh-fed slot film cooling scheme due to the strong “jetting” effect of coolant flow at the slot outlet. As the coolant jet ejecting from mesh-fed slot is capable of establishing more uniform film layer over the protected surface, the kidney vortices are illustrated to have weakly detrimental role on the film cooling performance. By the shaping of pin fins, the uniformity of coolant flow exiting mesh-fed slot is improved in comparison to the baseline case of circular shape, especially for the elliptical-shape pin-fin array. Therefore, the jetting effect of coolant flow is alleviated for the elliptical and drop-shaped pin-fin meshes when compared to the circular pin-fin mesh. In general, the pin-fin shape has nearly no influence on cooling effectiveness immediately downstream the film cooling-hole outlet. However, beyond x/s = 5, the elliptical and drop-shaped pin fins are demonstrated to be advantageous over the circular pin fins.
Extreme Response Prediction of Steel Risers Using a Four Parameter Distribution
Authors: Ibarra Miguel Alfonso Calderon , de Sousa Fernando Jorge Mendes , Sagrilo Luís Volnei Sudati , Low Ying Min
Published: November 2018

Short-term extreme response estimates are required in many areas of ocean and offshore engineering, such as steel risers design. As in many cases, the response in non-Gaussian, a theoretical solution, is usually not readily available for this purpose. Hermite transformation and Weibull-based models, among others, are some alternatives that have been used in connection with sampled response time series. In this work, a new approach is investigated. Recently, a four-parameter distribution known as the shifted generalized lognormal distribution (SGLD) has been presented in the literature. One of its main advantages is that it covers regions of skewness–kurtosis not covered by other distributions of common use in engineering. In this paper, the performance of this distribution is evaluated in the extreme values' estimation of the utilization ratios of steel riser sections. Three alternatives for using SGLD are investigated in two case studies of different dynamic behavior. The first one is a steel-lazy wave riser (SLWR) connected to a turret-moored FPSO (floating, production, storage and offloading unit) in 914 m water depth, and the second is a SLWR connected to a spread-mooring FPSO in a water depth of 1400 m. The results obtained by the SGLD-based analysis, which considered several simulation lengths, are compared to those obtained by means of an extreme value distribution fitted to episodical extremes obtained from many distinct realizations. The results of a traditional Weibull-fitting approach to the response peaks and those obtained with a Hermite transformation-based model are also presented for comparison.
Tribological Influences of CuO Into 3Y-TZP Ceramic Composite in Conformal Contact
Authors: Mazumder Subhrojyoti , Kumar Om Prakash , Kotnees Dinesh Kumar , Mandal Nilrudra
Published: November 2018

The aim of the study was to investigate the friction and wear phenomena of 3 mol % yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) ceramics with the inclusion of copper oxide (CuO) in large area conformal contact geometry. The pin-on-disk tribometer was used to conduct the dry sliding test using CuO/3Y-TZP as pin and alumina as counter surface. The coefficient of friction (μ) for CuO-added 3Y-TZP was decreased by ∼38% compared to pure 3Y-TZP due to formation of protective tribo film to the substrate. In addition, the experiments also showed that the specific wear rate (k) was reduced by ∼54% with the inclusion of CuO in to 3Y-TZP matrix. The different phases of the zirconia, copper, and yttria as well as the phase transformation before and after sliding test were identified by X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDS) analysis revealed the existence of CuO in the patchy layers in the worn-out surface of the tested CuO/3Y-TZP sample leading to lower coefficient of friction and improve the wear resistance against alumina counterface in conformal contact geometry. Severe wear mechanism was the dominating factor due to the local plastic deformation of the large number of asperities since the pair of contact was conformal.
Further Investigation on Acoustic Stall-Warning Approach in Compressors
Authors: Dong Xu , Li Fanyu , Xu Ruize , Sun Dakun , Sun Xiaofeng
Published: November 2018

A further investigation of an acoustic theory-based stall-warning approach is presented in this paper, which contains the basis of this approach and an application on a low-speed compressor (LSC) with a stabilization system. In the present work, this stall-warning approach is first explained through a numerical simulation in which the periodicity of pressure signals is analyzed, and then application experiments of this approach are actualized on a LSC with a stall precursor-suppressed (SPS) casing treatment (CT) as a stabilization system. For this stall-warning approach, a parameter named Rc is calculated through pressure signals of compressor to evaluate the periodicity of pressure signal, and statistical estimates are implemented on Rc so that the probabilities for Rc less than a threshold Rcth can be used as a criterion for stall warning. The numerical and experimental results both show that the signal resolution is determined by the sensor position, the prestall signal amplitude decreases rapidly with the increase of the distance between sensor and blades. Results also show that the probability increases significantly when the operating point is nearing the stall boundary. And at the same operating point, the probability value of Rc will decrease when the SPS CT is engaged. Through this stall-warning approach, a stabilization system based on SPS CT can be activated when the stall margin needs to be extended.
Seafloor mappers to compete for XPRIZE
Authors: Rosen Julia
Published: November 2018

Faster, cheaper autonomous systems could aid in resource extraction and science.
Moments to spare
Authors: Voosen Paul
Published: November 2018

California's new earthquake warning system delivers just seconds of notice. Even that is a victory.
Predicting reservoir hosts and arthropod vectors from evolutionary signatures in RNA virus genomes
Authors: Babayan Simon A. , Orton Richard J. , Streicker Daniel G.
Published: November 2018

Predicting hosts and vectors

During outbreaks of mysterious infections, events can rapidly become dangerous and confusing. A combination of increasing experience with outbreaks and genome-sequencing technology now means the pathogen can often be identified within days. But for some of the most frightening viral pathogens, the originating hosts and possible vectors often remain obscure. Babayanet al.took sequence data from more than 500 single-stranded RNA viruses (see the Perspective by Woolhouse) and used machine-learning algorithms to extract evolutionary signals imprinted in the virus sequence that offer information about its original hosts and if an arthropod vector, and what type, plays a part in the virus's natural ecology.

Science, this issue p.577; see also p.524
Editing nature: Local roots of global governance
Authors: Kofler Natalie , Collins James P. , Kuzma Jennifer , Marris Emma , Esvelt Kevin , Nelson Michael Paul , Newhouse Andrew , Rothschild Lynn J. , Vigliotti Vivian S. , Semenov Misha , Jacobsen Rowan , Dahlman James E. , Prince Shannon , Caccone Adalgisa , Brown Timothy , Schmitz Oswald J.
Published: November 2018

Environmental gene editing demands collective oversight
Extra strengthening and work hardening in gradient nanotwinned metals
Authors: Cheng Zhao , Zhou Haofei , Lu Qiuhong , Gao Huajian , Lu Lei
Published: November 2018

Stronger copper through twin power

Materials with structural gradients often have unique combinations of properties. Gradient-structured materials are found in nature and can be engineered. Cheng
et al.
made a structural gradient by introducing gradients of crystallographic twins into copper. This strategy creates bundles of dislocations in the crystal interiors, which makes the metal stronger than any of the individual components. This method offers promise for developing high-performance metals.

Science
, this issue p.
eaau1925
A general synthesis approach for supported bimetallic nanoparticles via surface inorganometallic chemistry
Authors: Ding Kunlun , Cullen David A. , Zhang Laibao , Cao Zhi , Roy Amitava D. , Ivanov Ilia N. , Cao Dongmei
Published: November 2018

More alloying on silica

Controlling the stoichiometry and achieving a high degree of alloying of metals at ultrasmall scales for catalysis can be difficult. Double complex salts, formed by a cation like Pd(NH
3
)
4
2+
and an anion like IrCl
6
2−
, should be excellent precursors but are poorly soluble and difficult to adsorb directly on metal oxide surfaces. Ding
et al.
show that sequentially adsorbing the cations and anions from organic solvents onto a silica surface, followed by heating in hydrogen, creates well-mixed nanoparticles, most less than 3 nanometers in diameter, for a variety of alloys. These materials were then tested as catalysts for acetylene hydrogenation to ethylene.

Science
, this issue p.
560
Catalytic palladium-oxyallyl cycloaddition
Authors: Trost Barry M. , Huang Zhongxing , Murhade Ganesh M.
Published: November 2018

Steps to smaller rings

Certain ring-forming reactions in organic chemistry are efficient because the orbital symmetries match up in the reactants and products. Oxyallyl ions tend to react with dienes in this paradigm to form seven-membered rings. Under palladium catalysis, Trost
et al.
redirected this reaction toward more common five-membered tetrahydrofuran rings by appending an ester to the diene. Although that pathway is symmetry-forbidden, the electron-withdrawing ester appears to stabilize a key intermediate along a stepwise route to the smaller ring.

Science
, this issue p.
564
Molecular, spatial, and functional single-cell profiling of the hypothalamic preoptic region
Authors: Moffitt Jeffrey R. , Bambah-Mukku Dhananjay , Eichhorn Stephen W. , Vaughn Eric , Shekhar Karthik , Perez Julio D. , Rubinstein Nimrod D. , Hao Junjie , Regev Aviv , Dulac Catherine , Zhuang Xiaowei
Published: November 2018

Mapping the brain, one neuron at a time

Spatial transcriptomics can link molecularly described cell types to their anatomical positions and functional roles. Moffitt
et al.
used a combination of single-cell RNA-sequencing and MERFISH (multiplexed error-robust fluorescence in situ hybridization) to map the identity and location of specific cell types within the mouse preoptic hypothalamus and surrounding areas of the brain (see the Perspective by Tasic and Nicovich). They related these cell types to specific behaviors via gene activity. The approach provides an unbiased description of cell types of the preoptic area, which are important for sleep, thermoregulation, thirst, and social behavior.

Science
, this issue p.
eaau5324
; see also p.
749
Evolving a pathogen to be protective
Authors: d'Enfert Christophe
Published: November 2018

The deadly fungus
Candida albicans
can be pushed to protect its mammalian host
Cancer enzyme affects Parkinson's disease
Authors: Brundin Patrik , Wyse Richard
Published: November 2018

New insights identify a possible target for slowing neurodegeneration
How to clean up the Ganges?
Authors: Shah Tushaar , Ray Chittaranjan , Lele Uma
Published: November 2018

For millennia, the Ganges River, holy to Hindus, has provided livelihoods, food, and water for Nepal, India, and Bangladesh. Last month, one of India's leading environmental activists died after a 111-day hunger strike, failing to evoke changes to save India's most revered river (known as Ganga). After years of unrelenting abuse, Ganga is now one of the world's worst polluted rivers. India's Prime Minister Narendra Modi vowed in 2014 to clean Ganga by 2019, but despite increased funding and much lip service, the river is more polluted than before. Mr. Modi needs a new strategy.