bluuebunny/crossref_metadata_2025 huggingface dataset:
Diatom-inferred aquatic impacts of the mid-Holocene eruption of Mount Mazama, Oregon, USA
Authors: Egan Joanne , Allott Timothy E.H. , Blackford Jeffrey J.
Published: September 2018

High-resolution diatom stratigraphies from mid-Holocene sediments taken from fringe and central locations in Moss Lake, a small lake in the foothills of the Cascade Range, Washington, have been analyzed to investigate the impacts (and duration) of tephra deposition on the aquatic ecosystem. Up to 50 mm of tephra was deposited from the climactic eruption of Mount Mazama 7958–7795 cal yr BP, with coincident changes in the aquatic ecosystem. The diatom response from both cores indicates a change in habitat type following blanket tephra deposition, with a decline in tychoplanktonic Fragilaria brevistriata and Staurosira venter and epiphytic diatom taxa indicating a reduction in aquatic macrophyte abundance. Additionally, the central core shows an increase in tychoplanktonic Aulacoseira taxa, interpreted as a response to increased silica availability following tephra deposition. Partial redundancy analysis, however, provides only limited evidence of direct effects from the tephra deposition, and only from the central core, but significant effects from underlying environmental changes associated with climatic and lake development processes. The analyses highlight the importance of duplicate analyses (fringe and central cores) and vigorous statistical analyses for the robust evaluation of aquatic ecosystem change.
Protecting the Right to Discriminate: The Second Great Migration and Racial Threat in the American West
Authors: RENY TYLER T. , NEWMAN BENJAMIN J.
Published: September 2018

Taking advantage of a unique event in American history, the Second Great Migration, we explore whether the rapid entry of African Americans into nearly exclusively White contexts triggered “racial threat” in White voting behavior in the state of California. Utilizing historical administrative data, we find that increasing proximity to previously White areas experiencing drastic Black population growth between 1940 to 1960 is associated with significant increases in aggregate White voter support for a highly racially-charged ballot measure, Proposition 14, which legally protected racial discrimination in housing. Importantly, we find that this result holds when restricting the analysis to all-White areas with high rates of residential tenure and low rates of White population growth. These latter findings indicate that this relationship materializes in contexts where a larger share of White voters were present during the treatment and exercised residential-choice before the treatment commenced, which is suggestive of a causal effect.
Air Conditioning the Arabian Peninsula
Authors: Günel Gökçe
Published: September 2018

With much of the Arabian Peninsula characterized by hot and arid weather conditions during long summer seasons, residents are forced to rely on air conditioning to cool their surroundings. Before the construction of air conditioning infrastructures, many would leave the coast during the summer months to head to oases, such as Al Ain near Abu Dhabi, or live in tents in the desert to find relief from the heat. From the 1950s, European and American building practices shaped the region with little consideration of vernacular design elements or energy conservation. These building practices introduced air conditioning as a cooling method. For instance, the 1951 Report of Operations to the Saudi Arab Government by the Arabian American Oil Company explained how “automobiles, air conditioning units, sewing machines, washing machines, refrigerators, and many other modern conveniences are now readily available” in Al Hasa, a significant region for Aramco's operations on the east of Saudi Arabia. By 1952, workers residing in Aramco's camps could have air conditioning units installed in their rooms on a rental basis. Air conditioning technology reconfigured urban environments, altering the relationship between indoors and outdoors, and ultimately constituting what Jiat-Hwee Chang and Tim Winter term a “thermal modernity” that transforms how built forms are imagined and inhabited. The current widespread use of air conditioning in the region is therefore connected not only to high temperatures, but also to how air conditioning is singled out as the ultimate technical fix in confronting the climate. Other solutions to managing heat, such as improving insulation mechanisms for residences and office buildings, have been less pervasive.
ENVIRONMENTAL FRAMING AND ITS LIMITS: CAMPAIGNS IN PALESTINE AND ISRAEL
Authors: McKee Emily
Published: September 2018

As activists frame campaigns, their region's broader cultural and political context intercedes. In Israel and Palestine attempts to work across national lines and undertake activism that links ecological, economic, and social issues have long been stymied. This article examines how the fraught historical and contemporary relationships of Israelis and Palestinians with land bestow both flexibility and limitations on their framing of campaigns. In particular, it ethnographically analyzes the framing of two projects—the building of an “eco-mosque” and a Jordan River restoration effort—to examine how activists grapple with frame flexibility and its limits. It finds that an Israeli tendency to deterritorialize environmental issues and curb environmental campaigns that are “too political” conflicts with Palestinian criticism of apolitical frames because they euphemize violence and domination. These cases demonstrate how local connotations can make or break environmental campaigns. The eco-adage, “Think global, act local” is not enough. One must think local, too.
Introduction: Physics, Technology, and Technics during the Interwar Period
Authors: Katzir Shaul
Published: September 2018

Historians, philosophers, and physicists portray the 1920s and 1930s as a period of major theoretical breakthrough in physics, quantum mechanics, which led to the expansion of physics into the core of the atom and the growth and strengthening of the discipline. These important developments in scientific inquiry into the micro-world and light have turned historical attention away from other significant historical processes and from other equally important causes for the expansion of physics. World War II, on the other hand, is often seen as the watershed moment when physics achieved new levels of social and technical engagement at a truly industrial scale. Historians have shown that military interests and government funding have shaped physics to unprecedented degree, and according to some, to the extent of discontinuity with earlier practices of research (Forman 1987; Kevles 1990; Kaiser 2002). In this vein, Stuart Leslie wrote, “Nothing in the prewar experience fully prepared academic scientists and their institutions for the scale and scope of a wartime mobilization that would transform the university, industry, and the federal government and their mutual interrelationships” (Leslie 1993, 6). While one can never befullyready for novelties, the contributors to this issue show that developments in interwar physics did prepare participants for their cold war interactions with industry and government.
Estimation of daily intake of polychlorinated biphenyls not similar to dioxins (NDL-PCB) from fish consumption in Spain in different population groups
Authors: Morales-Suárez-Varela Maria , Lopez Santana Nuria , Marti Requena Pedro , Beser Santos Mª Isabel , Peraita-Costa Isabel , Llopis-Gonzalez Agustin
Published: September 2018

Objective

To assess the daily intake of polychlorinated biphenyls not similar to dioxins (NDL-PCB) derived from fish consumption in Spain and compare it with tolerance limits in order to establish a safe threshold so that the nutritional benefits derived from fish consumption may be optimized.

Design

Analysis of NDL-PCB in fish samples and ecological study of the estimated intake of NDL-PCB from fish consumption in different Spanish population groups.

Subjects

National representative sample of the Spanish population.

Results

The intake of NDL-PCB was estimated in two different scenarios: upper bound (UB) and lower bound (LB). Estimating intake using the average concentration of NDL-PCB found in the fish samples, the intake for ‘other children’ is estimated as: 1·80 (UB) and 5·33 (LB) ng/kg per d at the 50th percentile (P50); 7·39 (UB) and 21·94 (LB) ng/kg per d at the 95th percentile (P95) of fish consumption. Estimated NDL-PCB intake shoots up in the toddler group, reaching values of 30·43 (UB) and 90·37 (LB) ng/kg per d at P95. Estimated intake values are lower than those previously estimated in Europe, something expected since in previous studies intake was estimated through total diet. In adults, our estimated values are 1·59 (UB) and 4·72 (LB) ng/kg per d at P50; 4·95 (UB) and 14·72 (LB) ng/kg per d at P95.

Conclusions

NDL-PCB concentration in fish is under the tolerance limits in most samples. However, daily intake in consumers of large quantities of fish should be monitored and special attention should be given to the youngest age groups due to their special vulnerability and higher exposure.
Ipatasertib, a novel Akt inhibitor, induces transcription factor FoxO3a and NF-κB directly regulates PUMA-dependent apoptosis
Authors: Sun Li , Huang Yuan , Liu Yeying , Zhao Yujie , He Xiaoxiao , Zhang Lingling , Wang Feng , Zhang Yingjie
Published: September 2018

Colon cancer is one of the three common malignant tumors, with a lower survival rate. Ipatasertib, a novel highly selective ATP-competitive pan-Akt inhibitor, shows a strong antitumor effect in a variety of carcinoma, including colon cancer. However, there is a lack of knowledge about the precise underlying mechanism of clinical therapy for colon cancer. We conducted this study to determine that ipatasertib prevented colon cancer growth through PUMA-dependent apoptosis. Ipatasertib led to p53-independent PUMA activation by inhibiting Akt, thereby activating both FoxO3a and NF-κB synchronously that will directly bind to PUMA promoter, up-regulating PUMA transcription and Bax-mediated intrinsic mitochondrial apoptosis. Remarkably, Akt/FoxO3a/PUMA is the major pathway while Akt/NF-κB/PUMA is the secondary pathway of PUMA activation induced by ipatasertib in colon cancer. Knocking out PUMA eliminated ipatasertib-induced apoptosis both in vitro and in vivo (xenografts). Furthermore, PUMA is also indispensable in combinational therapies of ipatasertib with some conventional or novel drugs. Collectively, our study demonstrated that PUMA induction by FoxO3a and NF-κB is a critical step to suppress the growth of colon cancer under the therapy with ipatasertib, which provides some theoretical basis for clinical assessment.
Automatic detection and counting of urediniospores of Puccinia striiformis f. sp. tritici using spore traps and image processing
Authors: Lei Yu , Yao Zhifeng , He Dongjian
Published: September 2018

The quantitative monitoring of airborne urediniospores of Puccinia striiformis f. sp. tritici (Pst) using spore trap devices in wheat fields is an important process for devising strategies early and effectively controlling wheat stripe rust. The traditional microscopic spore counting method mainly relies on naked-eye observation. Because of the great number of trapped spores, this method is labour intensive and time-consuming and has low counting efficiency, sometimes leading to huge errors; thus, an alternative method is required. In this paper, a new algorithm was proposed for the automatic detection and counting of urediniospores of Pst, based on digital image processing. First, images of urediniospores were collected using portable volumetric spore traps in an indoor simulation. Then, the urediniospores were automatically detected and counted using a series of image processing approaches, including image segmentation using the K-means clustering algorithm, image pre-processing, the identification of touching urediniospores based on their shape factor and area, and touching urediniospore contour segmentation based on concavity and contour segment merging. This automatic counting algorithm was compared with the watershed transformation algorithm. The results show that the proposed algorithm is efficient and accurate for the automatic detection and counting of trapped urediniospores. It can provide technical support for the development of online airborne urediniospore monitoring equipment.
Natural Products as Promising Leads Against Oncogenic Transcription Factors and Associated Signalling Pathways
Authors: Rahman Taufiq , Wezen Xavier Chee
Published: September 2018

Although often envisaged to be a disease of ancient origin, cancer continues to be a leading cause of death worldwide. Developing anti-cancer therapeutics has long been an active field of research in both academia and industries, providing us with several chemotherapeutic drugs to fight against cancer. However, side effects are inevitable with most of the current anti-cancer therapies and emergence of drug resistance in many cases has also been noted. The need for finding novel anti-cancer targets as well as potent drugs against cancer, therefore, remains still valid. Among potential targets for developing novel anti-cancer drugs, a few oncogenic transcription factors appear to be quite promising. Though traditionally regarded as ‘undruggable’, such a notion has been recently challenged by the growing evidence presenting strategies including small molecules of natural and synthetic origin. This chapter seeks to illustrate molecular targeting of few oncogenic transcription factors using some naturally occurring small molecules.
Roles played by polysaccharides with different structures in biomimetic synthesis of cuprous oxide
Authors: Liu Huan , Zhao Haizhou , Liu Fangtao , Li Xia , Zhang Ziqiu , Dong Lei , Yu Liangmin
Published: September 2018

In this study, several polysaccharide derivatives, carboxymethyl cellulose sodium (CMC), carboxymethyl chitin (CMCH) and sodium alginate (HCM), were introduced as the template in the preparation of Cu2O.
Tuning nuclear depolarization under MAS by electron T1e
Authors: Lund Alicia , Equbal Asif , Han Songi
Published: September 2018

T1e modulates nuclear depolarization in cross-effect nuclear polarization under magic-angle spining.
Spin–orbit coupling induced spin polarized valley states in SrRuO3/BiIrO3 heterostructures
Authors: Ji Yanli , Wang Xiaocha , Mi Wenbo
Published: September 2018

The valley polarization in SrRuO3 and BiIrO3 can be achieved with spin–orbit coupling, and tuning the Fermi level to the VBM can induce longitudinal transport with both spin and valley polarizations in SrRuO3.
MnIII-Peroxo adduct supported by a new tetradentate ligand shows acid-sensitive aldehyde deformylation reactivity
Authors: Denler Melissa C. , Wijeratne Gayan B. , Rice Derek B. , Colmer Hannah E. , Day Victor W. , Jackson Timothy A.
Published: September 2018

The new tetradentate L7BQ ligand (L7BQ = 1,4-di(quinoline-8-yl)-1,4-diazepane) has been synthesized and shown to support MnII and MnIII-peroxo complexes.
Crystal structure, luminescence properties, energy transfer, tunable occupation and thermal properties of a novel color-tunable phosphor NaBa1−zSrzB9O15:xCe3+,yMn2+
Authors: Bao Qi , Wang Zhijun , Sun Jiang , Wang Zhipeng , Meng Xiangyu , Qiu Keliang , Chen Yun , Yang Zhiping , Li Panlai
Published: September 2018

A series of color-tunable NaBa1−zSrzB9O15:Ce3+,Mn2+ phosphors were synthesized by a high temperature solid state method.
Mesogenic D–A fluorophores based on cyanovinyl and benzothiadiazole
Authors: Zhang Bei , Xiao Yulong , Fang Haipeng , Gao Hongfei , Wang Fuke , Cheng Xiaohong
Published: September 2018

Synthesized cyanovinyl and BTD based fluorophores displayed LC, Gel as well as optical waveguide and chemosensor properties.
Wetting of soft superhydrophobic micropillar arrays
Authors: Papadopoulos Periklis , Pinchasik Bat-El , Tress Martin , Vollmer Doris , Kappl Michael , Butt Hans-Jürgen
Published: September 2018

We image the bending of soft micropillars as liquid drops move on them and calculate the forces hindering drop motion.
Exacerbated metabolic changes in skeletal muscle of sickle cell mice submitted to an acute ischemia–reperfusion paradigm
Authors: Chatel Benjamin , Messonnier Laurent A. , Vilmen Christophe , Bernard Monique , Pialoux Vincent , Bendahan David
Published: September 2018

Sickle cell disease (SCD) is characterized by painful vaso-occlusive crisis. While there are several metabolic abnormalities potentially associated with muscular ischemia–reperfusion cycles that could be harmful in the context of SCD, the metabolic consequences of such events are still unknown. Ten controls (HbAA), thirteen heterozygous (HbAS), and ten homozygous (HbSS) SCD mice were submitted to a standardized protocol of rest–ischemia–reperfusion of the left leg during which adenosine triphosphate, phosphocreatine, and inorganic phosphate concentrations as well as intramuscular pH were measured using phosphorous magnetic resonance spectroscopy (MRS). Forty-eight hours later, skeletal muscles were harvested. Oxidative stress markers were then measured on the tibialis anterior. At the end of the ischemic period, HbSS mice had a lower pH value as compared with the HbAA and HbAS groups (P<0.01). During the reperfusion period, the initial rate of phosphocreatine resynthesis was lower in HbSS mice as compared with HbAA (P<0.05) and HbAS (P<0.01) animals. No significant difference among groups was observed regarding oxidative stress markers. HbSS mice displayed a higher intramuscular acidosis during the ischemic period while their mitochondrial function was impaired as compared with their HbAA and HbAS counterparts. These metabolic abnormalities could worsen the complications related to the pathology of SCD.
Multi‐focus image fusion through DCNN and ELM
Authors: Kong W.W. , Lei Y.
Published: September 2018

The purpose of researches on multi‐focus image fusion is to obtain a composed image where the objects are all captured in focus. Compared with the source images, the new one is of richer information and much better visual performance. Deep convolutional neural network (DCNN) and extreme learning machine (ELM) are combined to be a novel model (DCELM) to deal with the issue of multi‐focus image fusion. First, the source images are input into DCELM. Then, ELM is responsible for generating random weights between adjacent layers. Moreover, a convolution layer followed by a pooling one forms the basic unit of DCELM, which is used to get the feature maps of the source images from different perspectives. Finally, the above features are classified via ELM, and the information in focus from the source images can be fused into the final fused image. Experimental results demonstrate that the proposed fusion method well combines the better feature extraction ability of DCNN and much faster training speed of ELM, and its performance is superior to current state‐of‐the‐art typical ones.
End‐to‐end learning for arbitrary image style transfer
Authors: Yoon Y.B. , Kim M.S. , Choi H.C.
Published: September 2018

Real‐time arbitrary style transfer is based on a feed‐forward network, which consists of a pre‐trained encoder, a feature transformer, and a trainable decoder. However, the previous approach has some degrade in style quality of output image because the pre‐trained encoder is not optimised for image style transfer but originally for image classification task. An end‐to‐end learning scheme is introduced that optimises the encoder as well as the decoder for the task of arbitrary image style transfer. Experiments conducted with a public database proves that the style transfer network trained with the end‐to‐end learning scheme outperforms the network with a fixed encoder in terms of minimising both content and style losses and quality of the stylised images.
Disturbance observer‐based dynamic optimal setting control
Authors: Yin Liping , Wang Hong , Yan Xiaomo , Zhang Hongyan
Published: September 2018

This study deals with optimal operational control problems using a novel approach where a performance index is optimised by controller design together with set‐points reselection. Firstly, the operational indices are obtained by employing some optimisation algorithms. The controller is then designed for each closed loop to ensure that the controlled variables can track the set points in the ideal situation. Taking advantage of disturbance observers, the set‐points are reselected dynamically to minimise the effect caused by unexpected noises or disturbances. In the proposed method, the controller structures or parameters are never changed no matter what kind of disturbance affects the whole system. Finally, two simulations are given to demonstrate the effectiveness and convenience of the proposed strategy.
Gradient‐based iterative parameter estimation for bilinear‐in‐parameter systems using the model decomposition technique
Authors: Chen Mengting , Ding Feng , Yang Erfu
Published: September 2018

The parameter estimation issues of a block‐oriented non‐linear system that is bilinear in the parameters are studied, i.e. the bilinear‐in‐parameter system. Using the model decomposition technique, the bilinear‐in‐parameter model is decomposed into two fictitious submodels: one containing the unknown parameters in the non‐linear block and the other containing the unknown parameters in the linear dynamic one and the noise model. Then a gradient‐based iterative algorithm is proposed to estimate all the unknown parameters by formulating and minimising two criterion functions. The stochastic gradient algorithms are provided for comparison. The simulation results indicate that the proposed iterative algorithm can give higher parameter estimation accuracy than the stochastic gradient algorithms.
Observability of Boolean networks via STP and graph methods
Authors: Liu Huachao , Liu Yang , Li Yuanyuan , Wang Zhen , Alsaadi Fuad E.
Published: September 2018

This study addresses the observability of Boolean networks (BNs), using semi‐tensor product (STP) of matrices. First, unobservable states can be divided into two types, and the first type of unobservable states can be easily determined by blocking idea. Second, it is found that all states reaching to observable states are observable. Based on subgraph of transition matrix and blocking idea, the second type of unobservable states can be also determined. Approaches are obtained to directly determine some observable or unobservable states. An algorithm is designed for determining the observability of BNs as well. Examples are given to illustrate the effectiveness of the given results.
Poisson image denoising by piecewise principal component analysis and its application in single‐particle X‐ray diffraction imaging
Authors: Jin Qiyu , Miyashita Osamu , Tama Florence , Yang Jie , Jonic Slavica
Published: September 2018

This study describes an improved method for Poisson image denoising that is based on a state‐of‐the‐art Poisson denoising approach known as non‐local principal component analysis (NLPCA). The new method is referred to as PieceWise Principal Component Analysis (PWPCA). In PWPCA, the given image is first split into pieces, then NLPCA is run on each image piece, and finally the entire image is reconstituted by a weighted combination of the NLPCA‐processed image pieces. Using standard test images with Poisson noise, the authors show that PWPCA restores images more effectively than state‐of‐the‐art Poisson denoising approaches. In addition, and to the best of their knowledge, they show the first application of such approaches to single‐particle X‐ray free‐electron laser (XFEL) data. They show that the resolution of three‐dimensional reconstruction from XFEL diffraction images is improved when the data are preprocessed with PWPCA. XFELs are currently under rapid development to allow high‐resolution biomolecular structure determination at near‐physiological conditions. Data analysis methods developments follow these technological advances and are expected to have high impact in structural biology and drug design. This study contributes to these developments. As little experimental single‐particle XFEL data is available still, the XFEL experiments shown here were performed with simulated data.
Physical modelling of InGaAs–InAlAs APD and PIN photodetectors for >25 Gb/s data rate applications
Authors: Abdulwahid Omar S. , Kostakis Ioannis , Muttlak Saad G. , Sexton James , Ian Kawa , Missous Mohamed
Published: September 2018

Validated SILVACO physical models were exploited to optimise electrical and optical characteristics of 1.5 µm wavelength InAlAs–InGaAs Avalanche photodiodes and InGaAs PIN diodes. Optimised SILVACO models were created by selectively thinning down the absorption layers to further reduce the carrier transit time. Further optimisation was accomplished by scaling the light window aperture and mesa area sizes with the aim of reducing the device capacitances. The optimised PIN diode provides a maximum opto‐electric bandwidth of 35 GHz with a current responsivity of 0.4 A/W under −5 V bias voltage and 10 µW incident optical power. At 1 µW incident optical power, the maximum opto‐electric bandwidth and current responsivity of the optimised avalanche diode is 21 GHz and 1.4 A/W under −21.5 V bias voltage. The optimised APD and PIN photo‐detectors are capable of working at a data rate of up to 25 and 40 Gb/s, respectively.
Fat‐tree‐based optical networks‐on‐chip with WDM: crosstalk noise exploiting
Authors: Zhang Jingping , Xie Yiyuan , Wang Shujian , Ye Yichen , Liu Yuzhu , Pan Gaofeng , Liu Yong , Zhang Jiliang
Published: September 2018

Wavelength division multiplexing (WDM) technology as an extension of optical networks‐on‐chip (ONoCs) performance, can be applied to further overcome shortages of low bandwidth and high‐power consumption in multiprocessor systems‐on‐chip. Nevertheless, WDM‐based ONoCs (ONoCs_W) can encounter performance degradation and network scalability constraints because of its power loss and intrinsic crosstalk noise, especially the non‐linear four‐wave mixing crosstalk noise. Here, a formal systematical exploiting for worst‐case crosstalk noise and optical signal‐to‐noise ratio (OSNR) in arbitrary fat‐tree‐based ONoCs with WDM (FONoCs_W) is proposed. Meanwhile, the worst‐case OSNR optical link candidates are identified. To verify the proposed analysis method, FONoCs_W employing an optical turnaround router with WDM (WOTAR) is used for case study. The study results demonstrate that crosstalk noise significantly diminishes OSNR and restricts scalability of FONoCs_W. For instance, when input optical signal power equals 0 dBm in worst case, the average OSNR is −9.47 dB, the mean power of crosstalk noise for eight wavelengths is slightly greater than that of signal when the number of processor cores is 64; when it equals to 128, the average OSNR is −34.37 dB, decreased by 24.90 dB compared with the network with 64 processor cores.
FMCW multiple‐input multiple‐output radar with iterative adaptive beamforming
Authors: Eckhardt Johannes M. , Joram Niko , Figueroa Adrian , Lindner Bastian , Ellinger Frank
Published: September 2018

This work presents the design of a frequency modulated continuous wave (FMCW) multiple‐input multiple‐output radar system with collocated antennas. A key part of this article is the modification and application of the iterative adaptive algorithm (IAA) for digital beamforming to an FMCW radar system. The implemented system operates in the 2.4 GHz Industry, Scientific and Medical band with 100 MHz of bandwidth and consists of a transmit (TX) site with four antennas and a receive (RX) site with four antennas. The angular resolution is greatly improved from 15° with the common delay‐and‐sum beamforming to only 5° with IAA beamforming, which was verified by the results from a radar simulator and by a field test with the implemented hardware. The challenge of synchronisation and maintaining phase coherence in systems with remote TX and RX sites is also addressed by proposing a low‐frequency clock and trigger distribution system. This approach allows for cost‐efficient systems which can be distributed over longer distances.
Numerical study of the flow of R1270‐based nanorefrigerants in a circular tube subject to uniform heat flux
Authors: Zohud Mohammed , Ouadha Ahmed , Benzeguir Redouane
Published: September 2018

In this work, turbulent convective heat transfer of propylene (R1270)‐based nanorefrigerant in a circular tube with a uniform heat flux of 20 kW/m2 is numerically investigated using different types of nanoparticles namely Al2O3, CuO, SiO2 and ZnO with a volume concentration ranging from 0 to 5%. Computations have been carried out using the commercial CFD code Fluent for Reynolds number ranging from 20,000 to 100,000 and a nanoparticle diameter of 30 nm. Results in terms of the average convective heat transfer coefficients of both pure R1270 and R1270‐based nanorefrigerants have been compared successfully to values obtained using correlations from the literature. It is found that among nanorefrigerants studied, R1270/CuO performs the best, followed in order by R1270/Al2O3, R1270/ZnO and R1270/SiO2. It is also shown that the convective heat transfer coefficient is enhanced by increasing the Reynolds number and the nanoparticles volume concentration.
Electrical and optical properties of metal‐sandwiched ZnO/Ti/Cu/Ti/ZnO transparent conductive thin film
Authors: Lin Qijing , Zhao Na , Jiang Zhuangde , Meng Qingzhi , Chen Feng
Published: September 2018

Metal‐sandwiched zinc oxide (ZnO)/titanium (Ti)/copper (Cu)/Ti/ZnO thin film systems were fabricated using magnetron sputtering technology and then annealed using a rapid thermal annealing system at temperatures from 100 to 400°C. The influence of the Ti film thicknesses and annealing temperatures on the surface morphologies, sheet resistance and optical properties were studied. The surface morphologies change a little with the annealing temperature rises. The sheet resistances reduce with the Ti film thickness or annealing temperature increasing. Both the max transmittance and figure of merit reduce with the increase of Ti film thickness. The max transmittance increases with the temperature increasing from 100 to 300°C and then reduces. However, the figure of merit increases with the temperature increasing which indicates that the metal‐sandwiched ZnO/Ti/Cu/Ti/ZnO thin film system annealed at 400°C has the optimal performance.
Optimising electrochemical performance of lithium‐rich manganese‐based ternary cathode material x Li2MnO3 ·(1 − x)LiNi0.5Co0.3Mn0.2O2 by adjusting composition ratio
Authors: Zhang Hongliang , Deng Xiaoli , Dong Wenquan , Huang Haifu , Li Guangxu , Liang Xianqing , Zhou Wenzheng , Guo Jin
Published: September 2018

Herein, lithium‐rich manganese‐based cathode materials xLi2MnO3·(1−x)LiNi0.5Co0.3Mn0.2O2 with different chemical components (x = 0. 4, 0.5, 0.6 and 0.7) were prepared by a simple co‐precipitation method. The effects of different chemical components on the crystal structure and electrochemical properties of the lithium‐rich manganese‐based cathode materials were investigated by X‐ray diffraction, X‐ray photoelectron spectroscopy, charge–discharge, cyclic voltammetry and electrochemical impedance spectroscopy. The results indicate that the sample x Li2MnO3 ·(1 − x)LiNi0.5Co0.3Mn0.2O2 (x = 0.5) shows an optimum electrochemical performance: the first discharge capacity is high up to 240.71 mAh g−1 at 0.1 C; the discharge capacity can be maintained at 153 mAh g−1 after cycling 50 times when measured at a high rate of 2 C, and the good cycle stability at a high charge–discharge rate, where the discharge capacity was maintained at 123.26 mAh g−1 after 100 cycles at 5 C. Therefore, it can well balance the relationship between the specific capacity and rate capability.
Robust high bandwidth oscillation‐free digital feedforward compensator for micromachined actuators
Authors: Qi Shengbo , Wang Xinning , Li Chong , Dean Robert N.
Published: September 2018

Many micro‐electro‐mechanical systems applications suffer from large oscillations that come from high‐quality factors. Designing feedback controllers is challenging because of the very limited phase margin. This work proposes a feedforward compensator approach to cancel the oscillation behaviours without the constraints of the stability margins. The essential element of this mechanism is to create a series of zeros to cancel the undesired oscillation poles. It is a practical solution because: (i) the selection of the parameters of the compensator is straight forward and robust to the model variations and (ii) the implementation uses a pipeline digital circuit architecture that enables MHz range bandwidth.
Refining the origins of the gamma-ray binary 1FGL J1018.6–5856
Authors: Marcote B. , Ribó M. , Paredes J. M. , Mao M. Y. , Edwards P. G.
Published: September 2018

Context. Gamma-ray binaries are systems composed of a massive star and a compact object that exhibit emission from radio to very high energy gamma rays. They are ideal laboratories to study particle acceleration and a variety of physical processes that vary as a function of the orbital phase.

Aims. We aim to study the radio emission of the gamma-ray binary 1FGL J1018.6–5856 to constrain the emitting region and determine the peculiar motion of the system within the Galaxy to clarify its origin.

Methods. We analyzed an observation of 1FGL J1018.6–5856 with the Australian Long Baseline Array (LBA) at 8.4 GHz to obtain an accurate astrometry of the system and study its emission on milliarcsecond scales. We combined these data with the optical Gaia DR2 and UCAC4 catalogs to consolidate the astrometry information therein.

Results. The gamma-ray binary 1FGL J1018.6–5856 shows compact radio emission (< 3 mas or ≲20 au at ∼6.4 kpc distance), implying a brightness temperature of ≳5.6 × 106 K, and confirming its nonthermal origin. We report consistent results between the proper motion reported by Gaia DR2 and the positions obtained from the Gaia DR2, UCAC4, and LBA data (spanning 20 yr in total). We also determined the distance to 1FGL J1018.6–5856 to be 6.4−0.7+1.7. Together with the radial velocity of the source we computed its three-dimensional (3D) proper and peculiar motion within the Galaxy. We obtained a peculiar motion of 1FGL J1018.6–5856 on its regional standard of rest (RSR) frame of |u| = 45−9+30, with the system moving away from the Galactic plane. In the simplest scenario of a symmetric stellar core collapse we estimate a mass loss of 4 ≲ ΔM ≲ 9 M⊙ during the creation of the compact object.

Conclusions. 1FGL J1018.6–5856 exhibits compact radio emission similar to that detected in other gamma-ray binaries. We provide the first accurate peculiar motion estimations of the system and place it within the Galaxy. The obtained motion and distance excludes the physical relation of the binary source with the supernova remnant (SNR) G284.3−1.8.
Defining and characterizing wood-laden flows in rivers using home videos
Authors: Ruiz-Villanueva V. , Bürkli L. , Mazzorana B. , Mao L. , Ravazzolo D. , Iribarren P. , Wohl E. , Nakamura F. , Stoffel M.
Published: September 2018

Organic material (i.e., trees, branches, wood in general) is commonly neglected among the classical criteria to distinguish flow types, mostly due to the lack of direct observations of flows in which this load is significant. However, in forested basins, large amounts of wood can be transported. Here we define and characterize, for the first time, wood-laden flows and show that these flows may occur repeatedly in a river basin, carrying substantial amount of organic material, with probable impacts on the ecosystem and potential hazards. We propose a novel classification of flows from clear water to hypercongested wood debris flows, according to the composition of sediment, wood and water. Our results will contribute to a better understanding of flow phenomena in forested river basins, which may facilitate the design of better management strategies.
Geomorphic effects of gravel augmentation on the Old Rhine River downstream from the Kembs dam (France, Germany)
Authors: Chardon Valentin , Schmitt Laurent , Piégay Hervé , Arnaud Fanny , Serouilou Jordane , Houssier Jérôme , Clutier Anne
Published: September 2018

During the last 30 years, river restoration activities aiming to improve the functionality of degraded fluvial ecosystems increased markedly. For large rivers, it remains difficult to evaluate restoration efficiency and sustainability due to the lack of standardized monitoring metrics. From 2010 to 2016, three gravel augmentations were performed on the Old Rhine, a by-passed reach downstream from the Kembs dam (France- Germany). A geomorphic monitoring combining topo-bathymetric surveys, bedload tracking and hydraulic modelling allows to evaluate the successfulness of these actions. Results show that, to be mobilized, artificial sediment deposit should be located in concavity rather than convexity areas, due to higher shear stresses for moderate floods (Q2). Sediment starvation appeared rapidly on the restored reaches once the sediment wave moved downstream, as a consequence of limited upstream sediment supply. Bathymetric homogenization was observed along and downstream from the restored reaches without creation of new fluvial forms. This research highlights that future actions should include channel enlargement downstream of gravel augmentations, which would promote sediment deposition and habitat diversification. Sediments excavated during artificial widening could be stored and injected progressively into the upstream part of the Old Rhine to benefit the downstream sections.
Flume experiments on vegetated alternate bars
Authors: Calvani Giulio , Francalanci Simona , Solari Luca
Published: September 2018

The planform morphology of a river reach is the result of the combined actions of sediment motion (erosion, transport and deposition), hydrological regime, development and growth of vegetation. However, the interactions among these processes are still poorly understood and rarely investigated in laboratory flume experiments. In these experiments and also in numerical modelling, vegetation is usually represented by rigid cylinders, although it is widely recognized that this schematization cannot reproduce the effects of root stabilization and binding on riverbed sediment. In this work, we focus on the effects of added vegetation on morphological dynamics of alternate bars in a straight channel by means of flume experiments. We performed laboratory experiments reproducing hydraulic conditions that are typical of gravel bed rivers, in terms of water depth, bed slope and bed load; these conditions led to the formation of freely migrating alternate bars. We then employed rigid vegetation that was deployed on the reproduced alternate bars according to field observations. Various vegetation scenarios, in terms of density and spatial arrangement, were deployed in the flume experiments such to mimic different maintenance strategies. Results show the effects of rigid vegetation on the alternate bar configuration on the overall topographic pattern, the main alternate bar characteristics (such as amplitude and wavelength) and migration rate.
Characterization of bedload discharge in bores and very unsteady flows in an ephemeral channel
Authors: Halfi Eran , Deshpande Vishal , Johnson Joel P. L. , Katoshevski David , Reid Ian , Storz-Peretz Yael , Laronne Jonathan B.
Published: September 2018

Bedload flux under steady flow conditions is calculated by a multitude of available methods and equations. Yet, very little is known about the effect of very unsteady flows, such as flash floods and specifically bores, on bedload flux. The unpredictable nature of the floods together with many logistic difficulties and safety issues in monitoring explain this gap in knowledge. Global climate change may increase flood event occurrence, making their understanding even more crucial. The methodology of our study is based on automatically monitoring bedload flux (Reid slot samplers). Automation allowed high frequency monitoring of hydraulic parameters and bedload flux. Added novelty includes pipe and plate microphones for capturing acoustic signals of bedload sediments and 3-D velocimetry for characterizing turbulence. Alerting sensors and cellular data transmission enabled onsite presence upon bore arrival. Calibration between the acoustic indirect sensors and the direct slot samplers allows determination of bedload flux at a frequency of 1 Hz. Analyses of flood events indicate an increase in turbulent kinetic energy, instantaneous vertical velocities, shear stress and bedload flux during the rising limb within the first two minutes after bore arrival. This has implications for the likely destabilization of the channel bed and for bedload transport after passage of the bore and during subsequent, less unsteady flows.
Numerical modelling of bank failures during reservoir draw-down
Authors: Olsen Nils Reidar B. , Haun Stefan
Published: September 2018

Numerical algorithms are presented for modeling bank failures during reservoir flushing. The algorithms are based on geotechnical theory and the limit equilibrium approach to find the location and the depth of the slides. The actual movements of the slides are based on the solution of the Navier-Stokes equations for laminar flow with high viscosity. The models are implemented in the SSIIM computer program, which also can be used for modelling erosion of sediments from reservoirs. The bank failure algorithms are tested on the Bodendorf hydropower reservoir in Austria. Comparisons with measurements show that the resulting slides were in the same order of magnitude as the observed ones. However, some scatter on the locations were observed. The algorithms were stable for thick sediment layers, but instabilities were observed for thin sediment layers.
Field data and regional modeling of sediment supply to Emilia-Romagna’s river mouths
Authors: Cilli Silvia , Billi Paolo , Schippa Leonardo , Grottoli Edoardo , Ciavola Paolo
Published: September 2018

The Fiumi Uniti and Savio rivers are two small sandy-bed river systems which sediment yield contributes feeds part of the Emilia-Romagna beaches (Italy). Since the twentieth century the northern Adriatic coast has been affected by well-known beach retreat phenomena. As the sediment supply of these local rivers is not well known, an analysis of bed-load transport rates for the last 10 kilometres of the river has been done. Multiple analysis, supported by direct field measurements of the 2005-06 and 2017 years (still ongoing) have been realized. Complementary hydraulic investigation and modelling have been performed. Repeated bed-material samplings have been carried out during different flood conditions, obtaining a significant number of observations. Aiming at defining the behaviour of sediment-transport in these two rivers, this paper focuses on the analysis of threshold sediment transport condition. Several formulae available in literature were used to test the field measurements. All these criteria seem inappropriate to predict the threshold conditions for bed particle entrainment in terms of the value of bed shear stress. The inaccurate estimation given by these formulae is due to the fact that they do not consider natural grain-shape factors or are mainly suitable for gravel-bed rivers.
A PIV-based method to measure spatial gradients in bedload transport over a dune
Authors: Terwisscha van Scheltinga Renske C. , Friedrich Heide , Coco Giovanni
Published: September 2018

Traditional sediment transport equations calculate sediment flux from bed shear stress and the equations predict that transport increases nonlinearly with an increase in flow velocity. In a dune field, the dune geometry affects the flow velocity causing accelerating flow over the dune crest and de- and reattachment of the flow downstream of the dune crest. Sediment flux predicted from the reach-averaged bed shear stress gives fairly good results for dune fields, though their simplification is discordant for the complexity of the processes involved. Measurements of the displacement of sand particles over the dune bed were derived from highfrequency image capturing. The two main methods to measure particle velocities from images are particle tracking velocimetry (PTV) and particle image velocimetry (PIV). We compare individual particle tracking with a PIV-based correlation method. The PIV-based method promises to be a more efficient and effective approach to track particle motion. It is more suitable for the conditions of high bedload transport, as present in our experiments. The PIV-based method is based on using images of difference (IoD) and is fully automated and identifies spatial gradients at a support scale in the order of centimetres. Findings align with our general knowledge of accelerating flow over the dune crest. The mean streamwise particle velocity and activity over a dune stoss slope increase. At the scale of 0.026 m the observed particle velocity variability can be explained in the context of general onset and cessation of sediment transport, the effect of the reattachment zone and observed sweep/burst events. By decreasing the streamwise distance between cross-sections, the variations in mean particle velocity induced by superimposed bed defects are distinguished as well. The maximum particle velocity and activity occurred at the same location and consequently the location of the maximum transport over the dune crest was identified. The measurements bridge the gap between individual particle motion studies and (non-local) sediment transport flux measurements.
Estimation of sand suspension in a secondary channel of an alpine river
Authors: Camenen Benoît , Dramais Guillaume , Buffet Alexis , Thollet Fabien , Le Bescond Chloé , Lagouy Mickaël , Berni Céline , Le Coz Jérôme
Published: September 2018

In this paper, we present some first attempt to measure graded suspension of sands in an alpine river. It is a real challenge to measure gradedsuspensions of sands in such dynamic rivers. Specific measurements of the graded suspension in the middle of a secondary channel were attempted using a sampler that allows simultaneous sampling at three different elevations (5 cm, 10 cm, and 20 cm) above the bed. Very large concentrations (up to C = 40 g/l) of fine sediments in suspension were measured during a dam reservoir flushing event. It included large amounts of sand (from 10 to 60% of the measured concentration). A substantial graded suspension of sand was measured even for relatively low velocities. Sand fluxes estimates for varying bed shear stresses during the event are discussed. In particular, based on the measured bed shear stress, a semi-empirical formula developed for sand suspension is applied to test its ability to predict sand flux in alpine rivers. The sensibility of such formula to the grain size is very high whereas large uncertainties exist in the measurement (d50 varies from 0.1 to 0.3 mm depending on the sample), which makes its application difficult at the moment.
Reducing Darcy coefficient by using drag reduction methods in open-channel flows: Effect on discharge capacity and potential application to mitigate river flooding impact
Authors: Mignot Emmanuel , Riviere Nicolas , Lefevre Arnaud , Quillien Bernard
Published: September 2018

Drag reduction by polymer addition is a common strategy used to minimize friction losses in pipe flows but has not been tested in river flows. Present paper then aims at measuring backwater curves and velocity profiles within smooth and rough bed flume configurations to assess the capabilities of such polymer addition to decrease the water depth with regards to the use of plain water and thus increase the channel conveyance. The inclusion of a limited amount of polymers proves to be able to reduce the typical Darcy-Weisbach friction coefficient with regards to plain water by a factor 2 in smooth bed conditions and a factor 1.5 in rough bed conditions. Moreover, the vertical profiles of streamwise velocity appear to be hardly affected by the addition of such polymers. Whether such drag reduction would still be effective in real watercourses remains unknown and would now require field experiments at larger scale.