bluuebunny/crossref_metadata_2025 huggingface dataset:
A Three-Dimensional Enhanced Imaging Method on Human Body for Ultra-Wideband Multiple-Input Multiple-Output Radar
Authors: Zhao Dizhi , Jin Tian , Dai Yongpeng , Song Yongping , Su Xiangchenyang
Published: June 2018

High-resolution three-dimensional (3D) images can be acquired by the planar Multiple-Input Multiple-Output (MIMO) array radar making future work like detection and tracking easier. However, regarding portability and to save the costs of radar system, MIMO radar array adopts sparse type with limited number of antennas, so the imaging performance of a MIMO radar system is limited. In this paper, the 3D back projection imaging algorithm is verified by the experimental results of planar MIMO array for human body and an enhanced radar imaging method is proposed. The Lucy-Richardson (LR) algorithm based on deconvolution that is normally used for optical images is applied in radar images. Since the LR algorithm can amplify the noise level in a noise-contaminated system, a regularization method based on the Total Variation constraint is further incorporated in the LR algorithm to suppress the ill-posed characteristics. The proposed method shows a higher image Signal-to-Noise Ratio, a faster rate of convergence, a higher structure similarity and a smaller relative error compared to some similar methods. In the meantime, it also reduces the loss of image information after image enhancement and improves the radar image quality (get less grating lobe and clearer human limbs). The proposed method overcomes the disadvantages mentioned above and is verified by simulation experiment and real data measurement.
The Parallel Virtual Infinite Capacitor Applied to DC-Link Voltage Filtering for Wind Turbines
Authors: Lin Shuyue , Tong Xin , Zhao Xiaowei , Weiss George
Published: June 2018

We propose the parallel virtual infinite capacitor (PVIC) concept, which refers to two virtual infinite capacitors (VIC) connected to the same DC link and sharing one capacitor, one tuned to low frequencies (LF) and one tuned to high frequencies (HF). A PVIC can suppress voltage variations (ripple) in a wider frequency range than a usual VIC. The LF-VIC is controlled by a sliding mode controller to regulate the low-frequency component of the voltage to its reference value, and by a proportional-integral (PI) controller to maintain its state of charge within the desired operating range and achieve the ‘plug-and-play’ pattern of PVIC. The HF-VIC is controlled by another sliding mode controller to limit the high-frequency ripples and also to keep its state of charge within a reasonable operating interval. As our main application, we use the PVIC to replace a DC-link capacitor for voltage filtering on the DC link of a doubly fed induction generator (DFIG), which is driven by a WindPact (WP) 1.5-MW wind turbine under different grid conditions with turbulent wind input. The simulation study indicates that the PVIC provides much better voltage stabilisation than a DC-link capacitor with the same capacitance, especially in the low frequency range.
The Effect of Fuel Injection Equipment of Water-In-Diesel Emulsions on Micro-Explosion Behaviour
Authors: A. Ismael Mhadi , R. Heikal Morgan , A. Aziz A. Rashid , Crua Cyril
Published: June 2018

The number and size distributions of the water dispersed phase have a significant effect on both the long-term stability of an emulsion, and the probability of micro-explosions inside an engine. The emulsions are subjected to intense pressure and shear flow in the fuel injection equipment resulting in changes in the number and size distributions of the dispersed phase. These changes, in turn, have significant effects on the micro-explosion behavior of the droplets. To our knowledge, these effects are not known and have not been reported previously. To uncover some of these effects we carried out a comprehensive experimental investigation on an emulsion spray of 10% water (by volume) in diesel at different injection pressures of 500, 1000 and 1500 bar. A measurement system consisting of a high-speed camera was used to visualize the droplets’ micro-explosions and a thermocouple measured the temperature. Our measurements indicated that the emulsion shear in the injector nozzle shifted the emulsion droplet size distribution towards the smaller end resulting in a delay in the onset of micro-explosion. This delay in the onset of the micro-explosion is thought to be due to the decrease in the dispersed water coalescence rate which, in turn, increases the stability of the emulsion. The results also show that this delay in the onset of micro-explosion, and the temperature required for its onset, increased with injection pressure.
Critical Factors behind Construction Delay in Petrochemical Projects in Saudi Arabia
Authors: Alhajri Abdullah Rasheed , Alshibani Adel
Published: June 2018

This paper presents a study conducted to identify, assess, rank, and compare the most influencing factors causing schedule delays during the construction phase of petrochemical projects in Saudi Arabia. The methodology followed in this research to achieve the main aims is a combination of the comprehensive review of the literature and the interviewing of a number of local experts, which have resulted in identifying 23 factors. A total of 90 completed responses were gathered from 106 received responses. The study found that the most influencing factors causing schedule delays during the construction of petrochemical projects in Saudi Arabia are “Poor site management and supervision by contractors”; “Conflict between the main contractor and subcontractor”; “Poor planning and scheduling of projects by the contractor”; “Delays in material or equipment delivery”; and followed by “Delays in Handing Over Construction Site to the Contractor”. This paper is original in the sense that the areas of knowledge and practice covered in the identified factors were distributed and not available in one source. The factors are derived from personal interviews with selected project managers, project engineers, construction supervisors, and the others from different positions in the project department and from the relevant literature.
Vertical Precipitation Estimation Using Microwave Links in Conjunction with Weather Radar
Authors: Raich Roi , Alpert Pinhas , Messer Hagit
Published: June 2018

When monitoring rain rates by weather radar in semi-arid regions and when measuring precipitation at an arid region; precipitation particles, rain, or snowflakes may evaporate before reaching the ground. This evaporation is regarded as the Virga phenomenon and may cause a false representation of the precipitation amount that actually reaches the ground. The Virga occurs naturally when the air below the cloud is relatively dry, and continues until humidity below the base of the cloud is high enough to decrease the evaporation. This paper suggests a method of combining near ground Commercial Microwave Links (CMLs) attenuation measurements, in conjunction with data from several weather radar beams, observing different heights, in order to produce estimates of the vertical profile of the rain-rate values and of the Cloud Base level (ClB). We propose an estimation method and demonstrate it using real-data measurements of two major storm events in the dead-sea area. We verify the validity of the estimation near ground by comparing the results with Rain Gauges’ (RGs) actual measurements in addition to comparing the estimated ClB with real ClB observations of a nearby weather station. While the storm events selected indeed show great evaporation, the suggested method provides excellent results, with a correlation of up to 0.9615, when correlated with real measurements of RGs of two storms from 2014 to 2016.
Fuzzy Multi-Criteria Based Trust Management in Heterogeneous Federated Future Internet Testbeds
Authors: Dechouniotis Dimitrios , Dimolitsas Ioannis , Papadakis-Vlachopapadopoulos Konstantinos , Papavassiliou Symeon
Published: June 2018

A federation of heterogeneous testbeds, which provides a wide range of services, attracts many experimenters from academia and industry to evaluate novel future Internet architectures and network protocols. The candidate experimenter reserves the appropriate testbeds’ resources based on various diverse criteria. Since several testbeds offer similar resources, a trust mechanism between the users and the providers will facilitate the proper selection of testbeds. This paper proposes a fuzzy reputation-based trust framework that is based on a modification of the fuzzy VIKOR multi-criteria decision making method and combines the user’s opinion from previously-conducted experiments with retrieved monitoring data from the utilized testbeds, in order to quantify the reputation of each testbed and the credibility of the experimenter. The proposed framework can process various types of numeric and linguistic data in an on-line fashion and can be easily extended for new types of testbeds and services. Data from active federated testbeds are used to evaluate the performance of the fuzzy reputation-based trust framework under dynamic conditions. Furthermore, a comparison of the proposed framework with another existing state of the art trust framework for federated testbeds is presented, and its superiority is demonstrated.
Effect of Bitumen Emulsion and Polyester Resin Mixture on the Physico-Mechanical and Degradable Properties of Jute Fabrics
Authors: Akter Nasrin , Saha Joykrisna , Das Subrata , Khan Mubarak
Published: June 2018

Jute fabric samples were treated, with different formulations, using various proportions of bitumen emulsion and polyester (PE) resin in combined solutions. Styrene monomer was used as solvent, methyl ethyl ketone peroxide as cross-linking agent and cobalt naphtha as curing agent. The fabric specimens were immersed in the solution for 10–15 min, then pressed by a roller and dried at room temperature for 24 h. According to the percentage of bitumen emulsion and PE resin, the jute samples were obtained as J0 (untreated or raw jute), J1 (20% bitumen emulsion +10% PE), and J2 (10% bitumen emulsion +20% PE). It was revealed that tensile strength (TS) increased with bitumen emulsion and PE resin mixture treatment on both directions of jute fabrics where J2 showed the highest improvement of TS which were 61.4% and 44.7% for warp and weft direction respectively. Tensile strength (TS) decreased for all the samples in both directions after soil degradation. After 90 days, the untreated sample was totally degraded. Treated samples exhibited better stability than untreated ones in soil medium. Weight loss by soil degradation, moisture regain, moisture content and water uptake tests of the treated and untreated jute samples were also performed. Scanning electron microscopy (SEM) analysis was conducted to analyze the fiber surfaces of raw and treated jute fibers, finding significant differences as a result of treatment. Finally, the strategy of combining bitumen emulsion and PE resin for treatment, rather than using only PE resin, was found to produce a jute fabric which was not only better in all the above respects but also would be cheaper to produce.
Embracing Complexity to Advance the Science of Wildland Fire Behavior
Authors: Yedinak Kara M. , Strand Eva K. , Hiers J. Kevin , Varner J. Morgan
Published: June 2018

Wildland fire behavior research has largely focused on the steady-state interactions between fuels and heat fluxes. Contemporary research is revealing new questions outside the bounds of this simplified approach. Here, we explore the complex interactions taking place beyond steady-state assumptions through acknowledging the manufactured separation of research disciplines in fire science and the dynamic interactions that unfold when these separations are removed. Through a series of examples spanning at least four research disciplines and three ranges of spatial scale, we illustrate that by precisely defining parameters in a way that holds across scales and relaxing one steady-state simplification, we begin to capture the inherent variability that has largely eluded the fire behavior community. Through exploring examples of “deep interdependence,” we make the case that fire behavior science is well equipped to launch forward into more complex lines of inquiry.
Daily Intake Estimation for Young Children’s Ingestion of Residential Dust and Soils Contaminated with Chlorpyrifos and Cypermethrin in Taiwan
Authors: Yang Ya-Qing , Yiin Lih-Ming
Published: June 2018

We estimated the daily intakes of chlorpyrifos and cypermethrin via ingestion of indoor dust and outdoor soils using the Stochastic Human Exposure and Dose Simulation Model on a probabilistic approach for Taiwanese young children. Variables for the estimation, such as concentration, ingestion rate, and body weight, were adopted from previous studies. Monte Carlo simulation was performed with 1,000,000 iterations to simulate a single daily intake, which was shown in terms of percentage of the Acceptable Daily Intake (ADI) of either insecticide. The daily intakes are minimal with a 99% probability, but go up steeply at the 99.9th percentile (13.1% and 20.0% of the ADIs of chlorpyrifos and cypermethrin, respectively). The sensitivity analysis indicates that concentration is the most determinant variable for daily intake estimation, suggesting that high intakes may occur when insecticide concentrations are elevated. Compared to the data of daily intakes via dietary ingestion of vegetables derived from a previous study, the estimated non-dietary intakes are negligible until reaching the highest percentile. Consequently, the non-dietary ingestion exposure to either insecticide is commonly low for young children in Taiwan’s homes, unless high contamination (e.g., indoor insecticide application) occurs in the environment. Care has to be taken to avoid high contamination indoors.
Effect of an Intervention Program Based on Active Video Games and Motor Games on Health Indicators in University Students: A Pilot Study
Authors: Zurita-Ortega Félix , Chacón-Cuberos Ramón , Castro-Sánchez Manuel , Gutiérrez-Vela Francisco Luis , González-Valero Gabriel
Published: June 2018

(1) Background: High levels of physical inactivity caused by sedentary digital screen leisure constitute one of the main causes of the high levels of obesity observed in today’s society; (2) Methods: The present study aims to analyse the effect of a 12-week intervention program based on the application of active video games and motor games on health status indicators, problematic use of video games, and resilience capacity in university students. Besides, the content blocks of the Physical Education (PE) field are worked on through these devices, revealing their potential as an Information and Communications Technology (ICT) resource. A longitudinal study with a pre-experimental design with pretest–posttest measurements in a single group (n = 47) was performed, using as main instruments a Tanita TBF300® bioimpedance scale, the 20mSRT test for maximum oxygen consumption (VO2max), the Adherence to a Mediterranean Diet Test (KIDMED), the Questionnaire for Experiences Related to Video games (QERV) and the Connor-Davidson Resilience Scale (CD-RISC); (3) Results: The main results were a discrete improvement in the percentage of fat mass and VO2max, representing a small effect size in both cases. The quality of the diet followed and the confidence and tolerance for adversity as a resilience factor were also improved, representing a medium size effect for this last variable; (4) Conclusions: Despite the limitations of this study as it does not have a control group, the main conclusions are that active video games and motor games can be a motivational resource to follow an active lifestyle, helping to improve health status indicators in young adults.
Does the Effort Meet the Challenge in Promoting Low-Carbon City?—A Perspective of Global Practice
Authors: Lou Yingli , Shen Liyin , Huang Zhenhua , Wu Ya , Li Heng , Li Guijun
Published: June 2018

Global warming caused by carbon emissions has been recognized as a challenge to human sustainable development, and low-carbon city development is widely considered as an effective strategy to address this challenge. Numerous emission reduction measures have been implemented, and considerable efforts have been devoted in promoting low-carbon city. This paper examines whether sufficient efforts have been paid to these typical emission sectors, including Building, Industry, Energy Transformation, and Transportation by referring to the shared responsibility of each sector. The shared responsibility of individual emission sector is calculated by applying energy consumption data in 2014 World Energy Balance. The efforts contributed in emission reduction by each sector are examined by analyzing the low-carbon city work plans of 24 representative sample cities, which are selected globally. The research results demonstrate that sufficient emission reduction efforts have been paid in the Building sector and Transportation sector. But the Industry sector and Energy Transformation sector are less-attended in addressing emission reduction. The reason for the sufficient efforts paid in the Building sector and Transportation sector is considered as that the efforts for emission reduction in these two sectors can bring more co-benefits. However, emission reduction in Industrial sector is generally considered to have the effects of holding back economic growth, and the emission reduction in the sector of Energy Transformation will need enormous investment for advanced technologies. Policy for emission reduction in the Industry sector and Energy Transformation sector is indispensable to promote low-carbon city. This study appeals that (1) low-carbon city can be effectively implemented only if carbon reduction policy is adopted to all industrial activities; (2) multiple channels of financial resources should be established to support cities to mitigate carbon emissions in Industry sector; (3) cooperation on the development of clean energy technology between cities should be promoted; and (4) efforts should be paid to reduce carbon emission from using traditional energy transformation equipment by improving their efficiency.
Comparative Analysis between the In Vivo Biodistribution and Therapeutic Efficacy of Adipose-Derived Mesenchymal Stromal Cells Administered Intraperitoneally in Experimental Colitis
Authors: Lopez-Santalla Mercedes , Mancheño-Corvo Pablo , Escolano Amelia , Menta Ramon , Delarosa Olga , Redondo Juan M. , Bueren Juan A. , Dalemans Wilfried , Lombardo Eleuterio , Garin Marina I.
Published: June 2018

Mesenchymal stem cells (MSCs) have emerged as a promising treatment for inflammatory diseases. The immunomodulatory effect of MSCs takes place both by direct cell-to-cell contact and by means of soluble factors that leads to an increased accumulation of regulatory immune cells at the sites of inflammation. Similar efficacy of MSCs has been described regardless of the route of administration used, the inflammation conditions and the major histocompatibility complex context. These observations raise the question of whether the migration of the MSCs to the inflamed tissues is a pre-requisite to achieve their beneficial effect. To address this, we examined the biodistribution and the efficacy of intraperitoneal luciferase-expressing human expanded adipose-derived stem cells (Luci-eASCs) in a mouse model of colitis. Luci-eASC-infused mice were stratified according to their response to the Luci-eASC treatment. According to the stratification criteria, there was a tendency to increase the bioluminescence signal in the intestine at the expense of a decrease in the bioluminescence signal in the liver in the “responder” mice. These data thus suggest that the accumulation of the eASCs to the inflamed tissues is beneficial for achieving an optimal modulation of inflammation.
The Cyanobacterial Ribosomal-Associated Protein LrtA from Synechocystis sp. PCC 6803 Is an Oligomeric Protein in Solution with Chameleonic Sequence Properties
Authors: Contreras Lellys M. , Sevilla Paz , Cámara-Artigas Ana , Hernández-Cifre José G. , Rizzuti Bruno , Florencio Francisco J. , Muro-Pastor María Isabel , García de la Torre José , Neira José L.
Published: June 2018

The LrtA protein of Synechocystis sp. PCC 6803 intervenes in cyanobacterial post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family of proteins, involved in protein synthesis. In this work, we studied the conformational preferences and stability of isolated LrtA in solution. At physiological conditions, as shown by hydrodynamic techniques, LrtA was involved in a self-association equilibrium. As indicated by Nuclear Magnetic Resonance (NMR), circular dichroism (CD) and fluorescence, the protein acquired a folded, native-like conformation between pH 6.0 and 9.0. However, that conformation was not very stable, as suggested by thermal and chemical denaturations followed by CD and fluorescence. Theoretical studies of its highly-charged sequence suggest that LrtA had a Janus sequence, with a context-dependent fold. Our modelling and molecular dynamics (MD) simulations indicate that the protein adopted the same fold observed in other members of the HPF family (β-α-β-β-β-α) at its N-terminal region (residues 1–100), whereas the C terminus (residues 100–197) appeared disordered and collapsed, supporting the overall percentage of overall secondary structure obtained by CD deconvolution. Then, LrtA has a chameleonic sequence and it is the first member of the HPF family involved in a self-association equilibrium, when isolated in solution.
Circulating Tumour DNA Analysis for Tumour Genome Characterisation and Monitoring Disease Burden in Extramedullary Multiple Myeloma
Authors: Mithraprabhu Sridurga , Sirdesai Shreerang , Chen Maoshan , Khong Tiffany , Spencer Andrew
Published: June 2018

Mutational characterisation in extramedullary multiple myeloma (EM-MM) patients is challenging due to inaccessible EM plasmacytomas, unsafe nature of multiple biopsies and the spatial and temporal genomic heterogeneity apparent in MM (Graphical abstract). Conventional monitoring of disease burden is through serum markers and PET-CT, however these modalities are sometimes inadequate (serum markers), not performed in a timely manner (PET-CT) and uninformative for identifying mutations driving disease progression. DNA released into the blood by tumour cells (ctDNA) contains the predominant clones derived from the multiple disease foci. Blood-derived ctDNA can, therefore, provide a holistic illustration of the major drivers of disease progression. In this report, the utility of ctDNA, as an adjunct to currently available modalities in EM-MM, is presented for a patient with EM and oligosecretory (OS) disease. Whole exome sequencing of contemporaneously acquired tumour tissue and matched ctDNA samples revealed the presence of spatial and temporal genetic heterogeneity and the identification of pathways associated with drug resistance. Longitudinal monitoring of plasma samples revealed that ctDNA can be utilised to define the dynamic clonal evolution co-existent with disease progression and as an adjunct non-invasive marker of tumour burden.
Endogenous Antiangiogenic Factors in Chronic Kidney Disease: Potential Biomarkers of Progression
Authors: Tanabe Katsuyuki , Sato Yasufumi , Wada Jun
Published: June 2018

Chronic kidney disease (CKD) is a major global health problem. Unless intensive intervention is initiated, some patients can rapidly progress to end-stage kidney disease. However, it is often difficult to predict renal outcomes using conventional laboratory tests in individuals with CKD. Therefore, many researchers have been searching for novel biomarkers to predict the progression of CKD. Angiogenesis is involved in physiological and pathological processes in the kidney and is regulated by the balance between a proangiogenic factor, vascular endothelial growth factor (VEGF)-A, and various endogenous antiangiogenic factors. In recent reports using genetically engineered mice, the roles of these antiangiogenic factors in the pathogenesis of kidney disease have become increasingly clear. In addition, recent clinical studies have demonstrated associations between circulating levels of antiangiogenic factors and renal dysfunction in CKD patients. In this review, we summarize recent advances in the study of representative endogenous antiangiogenic factors, including soluble fms-related tyrosine kinase 1, soluble endoglin, pigment epithelium-derived factor, VEGF-A165b, endostatin, and vasohibin-1, in associations with kidney diseases and discuss their predictive potentials as biomarkers of progression of CKD.
BAS2 Is Required for Conidiation and Pathogenicity of Colletotrichum gloeosporioides from Hevea brasiliensis
Authors: An Bang , Wang Wenfeng , Guo Yunfeng , Wang Qiannan , Luo Hongli , He Chaozu
Published: June 2018

The hemibiotrophic fungi Colletotrichum gloeosporioides can cause anthracnose in rubber trees. By searching the genome of the fungal pathogen, the BAS2 encoding a biotrophy-associated secreted protein was identified. In the present study, the knockout mutants of BAS2 were constructed and the functions of BAS2 were investigated. The in vitro assays showed that BAS2 was not necessary for vegetative growth but was important for normal asexual reproduction in C. gloeosporioides. Pathogenicity assays suggested that BAS2 was involved in the process of the pathogen penetrating into the host tissue. Subcellular localization analysis revealed that BAS2 showed secretional characteristics in the fungi, and BAS2 mainly function as a cytoplasmic protein after being secreted into the host cell. Extracellular proteomics analysis revealed that BAS2 was required for the secretion of a series of proteins, which were important for the pathogenicity of C. gloeosporioides. These data lead to a better understanding of the biotrophy-associated secreted protein in regulating the pathogenesis of C. gloeosporioides.
Ubidecarenone-Loaded Nanostructured Lipid Carrier (UB-NLC): Percutaneous Penetration and Protective Effects Against Hydrogen Peroxide-Induced Oxidative Stress on HaCaT Cells
Authors: Wang Jianmin , Wang Huiyun , Xia Qiang
Published: June 2018

The objective of the investigation was to evaluate the percutaneous penetration of a ubidecarenone-loaded nanostructured lipid carrier (UB-NLC) and to illuminate the protective effects of UB-NLC for amelioration of hydrogen peroxide-induced oxidative damage on HaCaT cells. Ubidecarenone (UB) was encapsulated in a nanostructured lipid carrier (NLC), which was manufactured by homogenization. The morphological and dimensional properties of the prepared UB-NLC were studied by freeze-fracture transmission electron microscopy (FF-TEM) and photon correlation spectroscopy (PCS). Percutaneous penetration of UB-NLC was carried out by the Franz diffusion cells method. The change of cellular morphology was identified through a non-invasive time-lapse imaging system. The assessment was achieved via the evaluation of the levels of oxidative stress markers: reactive oxygen species (ROS), superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), and malondialdehyde (MDA). Percutaneous penetration of UB loaded in NLC formulation was enhanced in comparison to free UB. Preincubation of HaCaT cells with UB-NLC attenuated the level of intracellular generation of ROS. Lipid peroxidation was diminished by UB-NLC via inhibition of MDA formation. Pretreatment of cells with UB-NLC reestablished the activity of cellular antioxidant enzymes (SOD and GSH-PX). On the basis of the investigation conducted, results suggest that formulating UB as NLC is advantageous for topical delivery and treatment of oxidative stress-induced human diseases.
Engineering Cheerful Robots: An Ethical Consideration
Authors: Jones Raya A.
Published: June 2018

Socially interactive robots in a variety of forms and function are quickly becoming part of everyday life and bring with them a host of applied ethical issues. This paper concerns meta-ethical implications at the interface among robotics, ethics, psychology, and the social sciences. While guidelines for the ethical design and use of robots are necessary and urgent, meeting this exigency opens up the issue of whose values and vision of the ideal society inform public policies. The paper is organized as a sequence of questions: Can robots be agents of cultural transmission? Is a cultural shift an issue for roboethics? Should roboethics be an instrument of (political) social engineering? How could biases of the technological imagination be avoided? Does technological determinism compromise the possibility of moral action? The answers to these questions are not straightforwardly affirmative or negative, but their contemplation leads to heeding C. Wright Mills’ metaphor of the cheerful robot.
Regium-π vs Cation-π Interactions in M2 and MCl (M = Cu, Ag and Au) Complexes with Small Aromatic Systems: An ab Initio Study
Authors: Bauzá Antonio , Frontera Antonio
Published: June 2018

In this study we have theoretically analyzed (RI-MP2/def2-TZVP) the ability of metal moieties involving elements from group IB (Cu, Ag and Au) to establish either regium-π or cation-π interactions with π-systems of different electronic nature. More precisely, we have used M2 (oxidation state = 0) and MCl (oxidation state = +1) molecules where M = Cu, Ag and Au. On the other hand, we have used benzene, trifluorobenzene and hexafluorobenzene as aromatic rings. Furthermore, we have used Bader’s theory of “Atoms in Molecules” as well as NBO (Natural Bonding Orbital) calculations to further investigate and characterize the regium-π and cation-π complexes described herein. We believe our findings may be important when describing and characterizing both interactions in a chemical context, as well as to further explore the nature of the recently uncovered regium-π bond.
Exploration of Mechanical and Thermal Properties of CTAB-Modified MoS2/LLDPE Composites Prepared by Melt Mixing
Authors: Chhetri Suman , Adak Nitai Chandra , Samanta Pranab , Murmu Naresh Chandra , Kuila Tapas
Published: June 2018

Molybdenum disulfide (MoS2) was functionalized by cetyltrimethylammonium bromide (CTAB) through a one-pot hydrothermal technique, and subsequently, linear low-density polyethylene (LLDPE) composites were prepared. The attachment of alkyl chains of CTAB onto the MoS2 surface was confirmed by Fourier transform infrared spectroscopy (FTIR). The enhanced mechanical properties of the composites relative to neat LLDPE revealed good compatibility between MoS2 and LLDPE. The improvement in thermomechanical properties further substantiated good interaction between MoS2 and LLDPE. The thermal stability of the prepared composites showed a small decrease in onset degradation temperature. Nevertheless, the char residue formation was found to be promoted in the presence of MoS2.
LaBGen-P-Semantic: A First Step for Leveraging Semantic Segmentation in Background Generation
Authors: Laugraud Benjamin , Piérard Sébastien , Van Droogenbroeck Marc
Published: June 2018

Given a video sequence acquired from a fixed camera, the stationary background generation problem consists of generating a unique image estimating the stationary background of the sequence. During the IEEE Scene Background Modeling Contest (SBMC) organized in 2016, we presented the LaBGen-P method. In short, this method relies on a motion detection algorithm for selecting, for each pixel location, a given amount of pixel intensities that are most likely static by keeping the ones with the smallest quantities of motion. These quantities are estimated by aggregating the motion scores returned by the motion detection algorithm in the spatial neighborhood of the pixel. After this selection process, the background image is then generated by blending the selected intensities with a median filter. In our previous works, we showed that using a temporally-memoryless motion detection, detecting motion between two frames without relying on additional temporal information, leads our method to achieve the best performance. In this work, we go one step further by developing LaBGen-P-Semantic, a variant of LaBGen-P, the motion detection step of which is built on the current frame only by using semantic segmentation. For this purpose, two intra-frame motion detection algorithms, detecting motion from a unique frame, are presented and compared. Our experiments, carried out on the Scene Background Initialization (SBI) and SceneBackgroundModeling.NET (SBMnet) datasets, show that leveraging semantic segmentation improves the robustness against intermittent motions, background motions and very short video sequences, which are among the main challenges in the background generation field. Moreover, our results confirm that using an intra-frame motion detection is an appropriate choice for our method and paves the way for more techniques based on semantic segmentation.
A Survey of Low Voltage and Low Power Amplifier Topologies
Authors: Richelli Anna , Colalongo Luigi , Kovacs-Vajna Zsolt , Calvetti Giacomo , Ferrari Davide , Finanzini Marco , Pinetti Simone , Prevosti Enrico , Savoldelli Jacopo , Scarlassara Stefano
Published: June 2018

Reducing voltage supply is one of the most effective way to reduce the power consumption, but, on the other hand it is a challenging choice for the analog designers. In this paper, different topologies, well-suited for low voltage and ultra-low voltage supply, are depicted, investigated, designed in the same standard 180 nm technology and compared, highlighting the benefits and the possible applications.
Influence of Shot Peening on AlSi10Mg Parts Fabricated by Additive Manufacturing
Authors: Maamoun Ahmed H. , Elbestawi Mohamed A. , Veldhuis Stephen C.
Published: June 2018

The additive manufacturing (AM) of aluminum alloys promises to considerably enhance the performance of lightweight critical parts in various industrial applications. AlSi10Mg is one of the compatible Al alloys used in the selective laser melting of lightweight components. However, the surface defects obtained from the as-built parts affect their mechanical properties, and thus represent an obstacle to using them as final products. This study aims to improve the surface characteristics of the as-built AlSi10Mg parts using shot peening (SP). To achieve this goal, different SP intensities were applied to various surface textures of the as-built samples. The SP results showed a significant improvement in the as-built surface topography and a higher value of effective depth using 22.9 A intensity and Gp165 glass beads. The area near the shot-peened surface showed a significant microstructure refinement to a specific depth due to the dynamic precipitation of nanoscale Si particles. Surface hardening was also detected and high compressive residual stresses were generated due to severe plastic deformation. The surface characteristics obtained after SP could result in a significant improvement in the mechanical properties and fatigue strength, and thus promise performance enhancement for critical parts in various industrial applications.
Free Surface Characteristics of Flow around Two Side-by-Side Circular Cylinders
Authors: Li Dengsong , Yang Qing , Ma Xudong , Dai Guangqing
Published: June 2018

The three-dimensional free surface characteristics of flow around two equal diameter cylinders in a side-by-side arrangement were studied numerically. The flow fields were simulated with a three-dimensional finite volume method based on the RNG k-ɛ model for Reynolds number Re = 1.0 × 104. The volume-of-fluid method was applied to track air–water interfaces. Computations were performed for gap ratios of 1.25, 1.5, and 1.75 to examine the influence of the gap between two cylinders, and for distance to diameter ratios of 8.0 and 1.0 to study the wall proximity effects. The model was verified by comparing it with the other numerical and experimental results. The results indicated that the evolution of the free surface was periodic in time scale. A weak hydraulic jump occurs in the wake flow. Moreover, a significant difference between upstream and downstream free surface elevations exists in the vicinity of the cylinder. A runup in front of the cylinder and a ‘depression’ around the side edge were also observed. Computational results showed that the flow near the two cylinders was pushed outwards, and the flow between the cylinder and the wall was deflected inwards by the wall. The vortex structures on and near the free surface were closely correlated with the free surface. The shedding vortex far from the free surface was not affected.
Estimated Burden of Serious Fungal Infections in Mozambique
Authors: Sacarlal Jahit , Denning David
Published: June 2018

Mozambique is a sub-Saharan African country with limited information on the burden of fungal disease. We estimated the burden of serious fungal infections for the general healthy population and for those at risk, including those infected with HIV, patients with asthma, as well as those under intensive care. We consulted the Mozambican National Institute of Statistics Population and Housing Census report to obtain denominators for different age groups. We use modelling and HIV data to estimate the burdens of Pneumocystis jirovecii pneumonia (PCP), cryptococcal meningitis (CM) and candidiasis. Asthma, chronic obstructive pulmonary disease and tuberculosis data were used to estimate the burden of allergic bronchopulmonary aspergillosis (ABPA) and chronic pulmonary aspergillosis (CPA). In 2016, the Mozambique population was 26.4 million with 1.8 million people reported to be HIV-infected. Estimated annual incidence of fungal infections was: 33,380 PCP, 18,640 CM and 260,025 oral and oesophageal candidiasis cases. Following pulmonary tuberculosis, estimated numbers of people having chronic pulmonary aspergillosis (prevalence) and allergic bronchopulmonary aspergillosis complicating asthma are 18,475 and 15,626, respectively. Tinea capitis is common in children with over 1.1 million probably affected. We also highlight from studies in progress of high incidences of histoplasmosis, CM and Pneumocystis jirovecii in adult HIV-infected patients. Prospective epidemiology studies with sensitive diagnostics are required to validate these estimates.
Endophytic Fungi: A Source of Potential Antifungal Compounds
Authors: Deshmukh Sunil K. , Gupta Manish K. , Prakash Ved , Saxena Sanjai
Published: June 2018

The emerging and reemerging forms of fungal infections encountered in the course of allogeneic bone marrow transplantations, cancer therapy, and organ transplants have necessitated the discovery of antifungal compounds with enhanced efficacy and better compatibility. A very limited number of antifungal compounds are in practice against the various forms of topical and systemic fungal infections. The trends of new antifungals being introduced into the market have remained insignificant while resistance towards the introduced drug has apparently increased, specifically in patients undergoing long-term treatment. Considering the immense potential of natural microbial products for the isolation and screening of novel antibiotics for different pharmaceutical applications as an alternative source has remained largely unexplored. Endophytes are one such microbial community that resides inside all plants without showing any symptoms with the promise of producing diverse bioactive molecules and novel metabolites which have application in medicine, agriculture, and industrial set ups. This review substantially covers the antifungal compounds, including volatile organic compounds, isolated from fungal endophytes of medicinal plants during 2013–2018. Some of the methods for the activation of silent biosynthetic genes are also covered. As such, the compounds described here possess diverse configurations which can be a step towards the development of new antifungal agents directly or precursor molecules after the required modification.
Effects of Blank Quality on Press-Formed PEKK/Carbon Composite Parts
Authors: Donadei Valentina , Lionetto Francesca , Wielandt Michael , Offringa Arnt , Maffezzoli Alfonso
Published: June 2018

The causes of delamination and porosities during press forming of pre-consolidated flat laminates (blanks) made of carbon fiber-reinforced poly(ether ketone ketone) (PEKK) were addressed in this study. In particular, the quality of the blank laminate was investigated before and after infrared heating. The consolidation quality was evaluated by thickness measurements, non-destructive inspection (NDI), and optical microscopy. The experimental results confirmed that deconsolidation phenomena can be related to residual stresses formed during blank forming in an autoclave, then released during infrared heating (IR) of the blank, determining most of the defects in IR heated blanks. These defects, generated at the pre-heating stage, were not fully removed in the consolidation stage of the press forming process. An annealing treatment, performed on autoclave-consolidated blanks above the glass transition temperature of the matrix, was proposed to reduce the formation of defects during IR heating. The stress relaxation phenomena during annealing were modelled using a simple viscoelastic model.
Effects of Organic Modification of Montmorillonite on the Properties of Hydroxypropyl Di-Starch Phosphate Films Prepared by Extrusion Blowing
Authors: Qin Yang , Wang Wentao , Zhang Hui , Dai Yangyong , Hou Hanxue , Dong Haizhou
Published: June 2018

The knowledge gained from starch-nanocomposite-film research has not been fully applied commercially because of the lack of appropriate industrial processing techniques for nanofillers and starch films. Three organically modified montmorillonites (OMMTs) were prepared using a semidry kneading method. The effects of the OMMTs on the structures and properties of starch nanocomposite films, prepared by extrusion blowing, were investigated. The X-ray diffraction (XRD) analysis results revealed that the OMMTs with various quaternary ammonium salts possessed differing layer structures and d-space values. The results of the XRD and Fourier-transform infrared spectroscopy (FT-IR) showed that the starch–OMMT interaction resulted in a structural change, namely the starch–OMMT films possessed a balanced exfoliated and intercalated nanostructure, while the starch–MMT film possessed an exfoliated nanostructure with non-intercalated montmorillonite (MMT). The results of the solid-state nuclear magnetic resonance (NMR) analysis suggested that the starch-OMMT nanocomposite possessed comparatively large quantities of single-helix structures and micro-ordered amorphous regions. The starch–OMMT films exhibited good tensile strength (TS) (maximum of 6.09 MPa) and water barrier properties (minimum of 3.48 × 10−10 g·m·m−2·s−1·Pa−1). This study indicates that the addition of OMMTs is a promising strategy to improve the properties of starch films.
The Changes in the Morphology of Bi–Sb System under Centrifugal Force at Room Temperature
Authors: Wierzba Bartek , Nowak Wojciech J.
Published: June 2018

In this paper, the morphology evolution in a Bi–Sb system under the centrifugal force at room temperature is discussed. The rotation speed was 35,000 rotations per minute and the length of the arm (radii) was 88 mm. It is shown, that after the centrifugation the phases become oriented in the direction parallel to the direction of the centrifugal force. Moreover, the voids move in the direction opposite to the centrifugal force direction. The movements of such voids result in their coalescence and finally lead to formation of cracks at the interface between ordered and disordered part of the sample.
Synthesis of Mesoporous γ-Al2O3 with Spongy Structure: In-Situ Conversion of Metal-Organic Frameworks and Improved Performance as Catalyst Support in Hydrodesulfurization
Authors: Liu Dandan , Zhu Hongwei , Zhao Jinchong , Pan Longjun , Dai Pengcheng , Gu Xin , Li Liangjun , Liu Yunqi , Zhao Xuebo
Published: June 2018

Over the past decades, extensive efforts have been devoted to modulating the textural properties, morphology and microstructure of γ-Al2O3, since the physiochemical properties of γ-Al2O3 have close correlations with the performance of hydrotreating catalysts. In this work, a spongy mesoporous γ-alumina (γ-Al2O3) was synthesized using Al-based metal-organic frameworks (Al-MOFs) as precursor by two-step pyrolysis, and this Al-MOF-derived γ-Al2O3 was used as hydrodesulfurization (HDS) catalyst support, to explore the effect of support on the HDS performance. Compared with industrial γ-Al2O3, the spongy alumina displayed well-developed porosity with relatively high surface area, large pore volume, and abundant weak Lewis acid sites. Based on catalyst characterization and performance evaluation, sulfurized molybdenum and cobalt molecules were able to incorporate and highly disperse into channels of the spongy mesoporous alumina, increasing the dispersion of active catalytic species. The spongy γ-Al2O3 was also able to enhance the diffusion efficiency and mass transfer of reactant molecules due to its improved texture properties. Therefore, the corresponding catalyst presented higher activities toward HDS of dibenzothiophene (DBT) than that from industrial alumina. The spongy mesoporous γ-alumina synthesized by Al-MOFs provides a new alternative to further develop novel γ-alumina materials with different texture and various nanoporous structures, considering the diversity of MOFs with different compositions, topological structures, and morphology.
Boron Nitride Nanosheets/PNIPAM Hydrogels with Improved Thermo-Responsive Performance
Authors: Xue Shishan , Wu Yuanpeng , Wang Jiemin , Guo Meiling , Liu Dan , Lei Weiwei
Published: June 2018

Thermo-responsive hydrogel is an important smart material. However, its slow thermal response rate limits the scope of its applications. Boron nitride nanosheet-reinforced thermos-responsive hydrogels, which can be controlled by heating, were fabricated by in situ polymerization of N-isopropylacrylamide in the presence of boron nitride nanosheets. The hydrogels exhibit excellent thermo-responsiveness and much enhanced thermal response rate than that of pure poly(N-isopropylacrylamide) hydrogels. Interestingly, the hydrogels can be driven to move in aqueous solution by heating. Importantly, the composite hydrogel is hydrophilic at a temperature below lower critical solution temperature (LCST), while it is hydrophobic at a temperature above LCST. Therefore, it can be used for quick absorption and release of dyes and oils from water. All these properties demonstrate the potential of hydrogel composites for water purification and treatment.