bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactive Oxygen Species and Mitochondrial Dynamics: The Yin and Yang of Mitochondrial Dysfunction and Cancer Progression
Authors: Ježek Jan , Cooper Katrina , Strich Randy
Published: January 2018

Mitochondria are organelles with a highly dynamic ultrastructure maintained by a delicate equilibrium between its fission and fusion rates. Understanding the factors influencing this balance is important as perturbations to mitochondrial dynamics can result in pathological states. As a terminal site of nutrient oxidation for the cell, mitochondrial powerhouses harness energy in the form of ATP in a process driven by the electron transport chain. Contemporaneously, electrons translocated within the electron transport chain undergo spontaneous side reactions with oxygen, giving rise to superoxide and a variety of other downstream reactive oxygen species (ROS). Mitochondrially-derived ROS can mediate redox signaling or, in excess, cause cell injury and even cell death. Recent evidence suggests that mitochondrial ultrastructure is tightly coupled to ROS generation depending on the physiological status of the cell. Yet, the mechanism by which changes in mitochondrial shape modulate mitochondrial function and redox homeostasis is less clear. Aberrant mitochondrial morphology may lead to enhanced ROS formation, which, in turn, may deteriorate mitochondrial health and further exacerbate oxidative stress in a self-perpetuating vicious cycle. Here, we review the latest findings on the intricate relationship between mitochondrial dynamics and ROS production, focusing mainly on its role in malignant disease.
Transition Analysis and Its Application to Global Path Determination for a Biped Climbing Robot
Authors: Zhu Haifei , Gu Shichao , He Li , Guan Yisheng , Zhang Hong
Published: January 2018

Biped climbing robots are considered good assistants and (or) substitutes for human workers carrying out high-rise truss-associated routine tasks. Flexible locomotion on three-dimensional complex trusses is a fundamental skill for these robots. In particular, the capability to transit from one structural member to another is paramount for switching objects to be climbed upon. In this paper, we study member-to-member transition and its utility in global path searching for biped climbing robots. To compute operational regions for transition, hierarchical inspection of safety, reachability, and accessibility of grips is taken into account. A novel global path rapid determination approach is subsequently proposed based on the transition analysis. This scheme is efficient for finding feasible routes with respect to the overall structural environment, which also benefits the subsequent grip and motion planning. Simulations are conducted with Climbot, our self-developed biped climbing robot, to verify the efficiency of the presented method. Results show that our proposed method is able to accurately determine the operational region for transition within tens of milliseconds and can obtain global paths within seconds in general.
Structural Optimization of a High-Speed Press Considering Multi-Source Uncertainties Based on a New Heterogeneous TOPSIS
Authors: Cheng Jin , Zhang Yangyan , Feng Yixiong , Liu Zhenyu , Tan Jianrong
Published: January 2018

In order to achieve high punching precision, good operational reliability and low manufacturing cost, the structural optimization of a high-speed press in the presence of a set of available alternatives comprises a heterogeneous multiple-attribute decision-making (HMADM) problem involving deviation, fixation, cost and benefit attributes that can be described in various mathematical forms due to the existence of multi-source uncertainties. Such a HMADM problem cannot be easily resolved by existing methods. To overcome this difficulty, a new heterogeneous technique for order preference by similarity to an ideal solution (HTOPSIS) is proposed. A new approach to normalization of heterogeneous attributes is proposed by integrating the possibility degree method, relative preference relation and the attribute transformation technique. Expressions for determining positive and negative ideal solutions corresponding to heterogeneous attributes are also developed. Finally, alternative structural configurations are ranked according to their relative closeness coefficients, and the optimal structural configuration can be determined. The validity and effectiveness of the proposed HTOPSIS are demonstrated by a numerical example. The proposed HTOPSIS can also be applied to structural optimization of other complex equipment, because there is no prerequisite of independency among various attributes for its application.
Pore Solution pH for the Corrosion Initiation of Rebars Embedded in Concrete under a Long-Term Natural Carbonation Reaction
Authors: Liu Xiguang , Niu Ditao , Li Xingchen , Lv Yao , Fu Qiang
Published: January 2018

This paper presents an in-situ inspection and experimental investigation on the pore solution pH of concrete cover for the corrosion initiation of rebars under a long-term natural carbonation reaction. A 77-year-old steel mill was inspected, and 35 concrete column cover samples were collected to test the pH of the pore solution and phase compositions layer by layer. The variation in pH and phase compositions of the concrete along the cover depth was studied. The in-situ inspection results indicate that the rebar embedded in concrete had begun to corrode when the carbonation depth was almost less than one-third of the cover depth. The corrosion initiation of rebars embedded in concrete can occur when the pH is between 11.3 and 12.1. The pore solution pH test results and X-ray diffraction (XRD) analysis indicated that there is a semi-carbonated zone between the fully carbonated zone and the rebar. The pH of a fully carbonated zone is in a range of 8.0–9.5, and the pH of a semi-carbonated zone is between 9.5 and 12.1.
Acknowledgement to Reviewers of Biomedicines in 2017
Authors:   Biomedicines Editorial Office
Published: January 2018

Peer review is an essential part in the publication process, ensuring that Biomedicines maintains high quality standards for its published papers[...]
Sophisticated Fowl: The Complex Behaviour and Cognitive Skills of Chickens and Red Junglefowl
Authors: Garnham Laura , Løvlie Hanne
Published: January 2018

The world’s most numerous bird, the domestic chicken, and their wild ancestor, the red junglefowl, have long been used as model species for animal behaviour research. Recently, this research has advanced our understanding of the social behaviour, personality, and cognition of fowl, and demonstrated their sophisticated behaviour and cognitive skills. Here, we overview some of this research, starting with describing research investigating the well-developed senses of fowl, before presenting how socially and cognitively complex they can be. The realisation that domestic chickens, our most abundant production animal, are behaviourally and cognitively sophisticated should encourage an increase in general appraise and fascination towards them. In turn, this should inspire increased use of them as both research and hobby animals, as well as improvements in their unfortunately often poor welfare.
Acknowledgement to Reviewers of Cryptography in 2017
Authors:   Cryptography Editorial Office
Published: January 2018

Peer review is an essential part in the publication process, ensuring that Cryptography maintains high quality standards for its published papers.[...]
Effects of Disorder on the Pressure-Induced Mott Transition in κ-(BEDT-TTF)2Cu[N(CN)2]Cl
Authors: Gati Elena , Tutsch Ulrich , Naji Ammar , Garst Markus , Köhler Sebastian , Schubert Harald , Sasaki Takahiko , Lang Michael
Published: January 2018

We present a study of the influence of disorder on the Mott metal-insulator transition for the organic charge-transfer salt κ -(BEDT-TTF) 2 Cu[N(CN) 2 ]Cl. To this end, disorder was introduced into the system in a controlled way by exposing the single crystals to X-ray irradiation. The crystals were then fine-tuned across the Mott transition by the application of continuously controllable He-gas pressure at low temperatures. Measurements of the thermal expansion and resistance show that the first-order character of the Mott transition prevails for low irradiation doses achieved by irradiation times up to 100 h. For these crystals with a moderate degree of disorder, we find a first-order transition line which ends in a second-order critical endpoint, akin to the pristine crystals. Compared to the latter, however, we observe a significant reduction of both, the critical pressure p c and the critical temperature T c . This result is consistent with the theoretically-predicted formation of a soft Coulomb gap in the presence of strong correlations and small disorder. Furthermore, we demonstrate, similar to the observation for the pristine sample, that the Mott transition after 50 h of irradiation is accompanied by sizable lattice effects, the critical behavior of which can be well described by mean-field theory. Our results demonstrate that the character of the Mott transition remains essentially unchanged at a low disorder level. However, after an irradiation time of 150 h, no clear signatures of a discontinuous metal-insulator transition could be revealed anymore. These results suggest that, above a certain disorder level, the metal-insulator transition becomes a smeared first-order transition with some residual hysteresis.
Analysis of Halogen and Other σ-Hole Bonds in Crystals
Authors: Politzer Peter , Murray Jane
Published: January 2018

Schneider has observed that [1]: “ . . . the chemistry of the last century was largely the chemistry of covalent bonding, whereas that of the present century is more likely to be the chemistry of noncovalent binding.”[...]
Long-Term WiFi Fingerprinting Dataset for Research on Robust Indoor Positioning
Authors: Mendoza-Silva Germán , Richter Philipp , Torres-Sospedra Joaquín , Lohan Elena , Huerta Joaquín
Published: January 2018

WiFi fingerprinting, one of the most popular methods employed in indoor positioning, currently faces two major problems: lack of robustness to short and long time signal changes and difficult reproducibility of new methods presented in the relevant literature. This paper presents a WiFi RSS (Received Signal Strength) database created to foster and ease research works that address the above-mentioned two problems. A trained professional took several consecutive fingerprints while standing at specific positions and facing specific directions. The consecutive fingerprints may enable the study of short-term signals variations. The data collection spanned over 15 months, and, for each month, one type of training datasets and five types of test datasets were collected. The measurements of a dataset type (training or test) were taken at the same positions and directions every month, in order to enable the analysis of long-term signal variations. The database is provided with supporting materials and software, which give more information about the collection environment and eases the database utilization, respectively. The WiFi measurements and the supporting materials are available at the Zenodo repository under the open-source MIT license.
The Fractality of Polar and Reed–Muller Codes
Authors: Geiger Bernhard
Published: January 2018

The generator matrices of polar codes and Reed–Muller codes are submatrices of the Kronecker product of a lower-triangular binary square matrix. For polar codes, the submatrix is generated by selecting rows according to their Bhattacharyya parameter, which is related to the error probability of sequential decoding. For Reed–Muller codes, the submatrix is generated by selecting rows according to their Hamming weight. In this work, we investigate the properties of the index sets selecting those rows, in the limit as the blocklength tends to infinity. We compute the Lebesgue measure and the Hausdorff dimension of these sets. We furthermore show that these sets are finely structured and self-similar in a well-defined sense, i.e., they have properties that are common to fractals.
Explicit Multipole Formulas for Calculating Thermal Resistance of Single U-Tube Ground Heat Exchangers
Authors: Claesson Johan , Javed Saqib
Published: January 2018

Borehole thermal resistance is both an important design parameter and a key performance characteristic of a ground heat exchanger. Another quantity that is particularly important for ground heat exchangers is the internal thermal resistance between the heat exchanger pipes. Both these resistances can be calculated to a high degree of accuracy by means of the well-known multipole method. However, the multipole method has a fairly intricate mathematical algorithm and is thus not trivial to implement. Consequently, there is considerable interest in developing explicit formulas for calculating borehole resistances. This paper presents derivation and solutions of newly derived second-order and higher-order multipole formulas for calculating borehole thermal resistance and total internal thermal resistance of single U-tube ground heat exchangers. A new and simple form of the first-order multipole formula is also presented. The accuracy of the presented formulas is established by comparing them to the original multipole method. The superiority of the new higher-order multipole formulas over the existing formulas is also demonstrated.
Hydrothermal Carbonization: Modeling, Final Properties Design and Applications: A Review
Authors: Román Silvia , Libra Judy , Berge Nicole , Sabio Eduardo , Ro Kyoung , Li Liang , Ledesma Beatriz , Álvarez Andrés , Bae Sunyoung
Published: January 2018

Active research on biomass hydrothermal carbonization (HTC) continues to demonstrate its advantages over other thermochemical processes, in particular the interesting benefits that are associated with carbonaceous solid products, called hydrochar (HC). The areas of applications of HC range from biofuel to doped porous material for adsorption, energy storage, and catalysis. At the same time, intensive research has been aimed at better elucidating the process mechanisms and kinetics, and how the experimental variables (temperature, time, biomass load, feedstock composition, as well as their interactions) affect the distribution between phases and their composition. This review provides an analysis of the state of the art on HTC, mainly with regard to the effect of variables on the process, the associated kinetics, and the characteristics of the solid phase (HC), as well as some of the more studied applications so far. The focus is on research made over the last five years on these topics.
Numerical Investigation of AdBlue Droplet Evaporation and Thermal Decomposition in the Context of NOx-SCR Using a Multi-Component Evaporation Model
Authors: Nishad Kaushal , Sadiki Amsini , Janicka Johannes
Published: January 2018

To cope with the progressive tightening of the emission regulations, gasoline and diesel engines will continuously require highly improved exhaust after-treatment systems. In the case of diesel engines, the selective catalytic reduction (SCR) appears as one of the widely adopted technologies to reduce NOx (nitrogen oxides) emissions. Thereby, with the help of available heat from exhaust gas, the injected urea–water solution (UWS) turns inside the exhaust port immediately into gaseous ammonia (NH3) by evaporation of mixture and thermal decomposition of urea. The reaction and conversion efficiency mostly depend upon the evaporation and subsequent mixing of the NH3 into the exhaust gas, which in turn depends upon the engine loading conditions. Up to now, the aggregation of urea after evaporation of water and during the thermal decomposition of urea is not clearly understood. Hence, various scenarios for the urea depletion in the gaseous phase that can be envisaged have to be appraised under SCR operating conditions relying on an appropriate evaporation description. The objective of the present paper is therefore fourfold. First, a reliable multi-component evaporation model that includes a proper binary diffusion coefficient is developed for the first time in the Euler–Lagrangian CFD (computational fluid dynamics) framework to account properly for the distinct evaporation regimes of adBlue droplets under various operating conditions. Second, this model is extended for thermal decomposition of urea in the gaseous phase, where, depending on how the heat of thermal decomposition of urea is provided, different scenarios are considered. Third, since the evaporation model at and around the droplet surface is based on a gas film approach, how the material properties are evaluated in the film influences the process results is reported, also for the first time. Finally, the impact of various ambient temperatures on the adBlue droplet depletion characteristics as well as the effect of gravity is pointed out. The prediction capability of the model variants is assessed by comparing the achieved results to each other and with experimental data. It turns out that satisfactory agreement between experiment and numerical predictions is achieved for a wide range of operating temperatures by using correlations by “Wilke and Lee” for urea and by “Fuller et al.” for water. The results are essentially sensitive to gravity. From subsequent comparisons of different ways to account for the thermal decomposition in the gaseous urea, a significant difference is observed. Finally, the 1/3 film rule widely used for evaluating the material properties in the film shows accurate prediction of both evaporation and thermal decomposition regimes of urea.
Relationship between Net Primary Productivity and Forest Stand Age under Different Site Conditions and Its Implications for Regional Carbon Cycle Study
Authors: Wang Bin , Li Mingze , Fan Wenyi , Yu Ying , Chen Jing
Published: January 2018

Net primary productivity (NPP) is a key component in the terrestrial ecosystem carbon cycle, and it varies according to stand age and site class index (SCI) for different forest types. Here we report an improved method for describing the relationships between NPP and stand age at various SCI values for the main forest types and groups in Heilongjiang Province, China, using existing yield tables, biomass equations, and forest inventory data. We calculated NPP as the sum of four components: Annual accumulation of live biomass, annual mortality of biomass, foliage turnover, and fine root turnover in soil. We also consider the NPP of understory vegetation or moss. These NPP-age relationships under different site conditions indicate that the NPP values of broadleaved and coniferous, as well as broadleaved mixed forests increase rapidly and reach a maximum when in young forests. However, for coniferous forest types, the maximum NPP generally occurs in mature forests. In addition, a higher SCI leads to a higher NPP value. Finally, we input these NPP-age relationships at various SCI values into the Integrated Terrestrial Ecosystem Carbon (InTEC) model to modify NPP modeling to estimate NPP in Heilongjiang Province in China from 2001 to 2010. All of the results showed that the methods reported in this study provide a reliable approach for estimating regional forest carbon budgets.
Contribution of Ecological and Socioeconomic Factors to the Presence and Abundance of Invasive Tree Species in Mississippi, USA
Authors: Zhai Jun , Grebner Donald , Grala Robert , Fan Zhaofei , Munn Ian
Published: January 2018

Invasive tree species cause increasing damage to the environment and local economies. Previous studies have seldom treated the presence and abundance of invasive species as different phenomena. Using Classification and Regression Trees (CART) analysis, important driving factors affecting the presence and abundance of invasive tree species in Mississippi were identified. These selected factors were spatially analyzed using a spatial lag model at the county level. The empirical results from the spatial lag model showed that: (1) the presence of invasive tree species was more likely at lower elevations, private ownerships, and in counties with higher per capita annual income; and (2) the abundance of invasive tree species was related to stand age, and elevation. The odds ratio revealed that the presence was most affected by per capita mean annual income. This result might reflect impacts from intensified urban development and alteration of the landscape. As revealed by the coefficients, the abundance was most strongly affected by stand age. Thus, management prescriptions designed to monitor and control invasions should target young private forestlands at low elevations in counties with higher per capita mean annual income.
Comparison between the Second and Third Generations of the CRONE Controller: Application to a Thermal Diffusive Interface Medium
Authors: Moreau Xavier , Abi Zeid Daou Roy , Christophy Fady
Published: January 2018

The control of thermal interfaces has gained importance in recent years because of the high cost of heating and cooling materials in many applications. Thus, the main focus in this work is to compare the second and third generations of the CRONE controller (French acronym of Commande Robuste d’Ordre Non Entier), which means a non-integer order robust controller, and to synthesize a robust controller that can fit several types of systems. For this study, the plant consists of a rectangular homogeneous bar of length L, where the heating element in applied on one boundary, and a temperature sensor is placed at distance x from that boundary (x is considered very small with respect to L). The type of material used is the third parameter, which may help in analyzing the robustness of the synthesized controller. The originality of this work resides in controlling a non-integer plant using a fractional order controller, as, so far, almost all of the systems where the CRONE controller has been implemented were of integer order. Three case studies were defined in order to show how and where each CRONE generation controller can be applied. These case studies were chosen in such a way as to influence the asymptotic behavior of the open-loop transfer function in the Black–Nichols diagram in order to point out the importance of respecting the conditions of the applications of the CRONE generations. Results show that the second generation performs well when the parametric uncertainties do not affect the phase of the plant, whereas the third generation is the most robust, even when both the phase and the gain variations are encountered. However, it also has some limitations, especially when the temperature to be controlled is far from the interface when the density of flux is applied.
Polarization: A Method to Reveal the True Nature of the Dusty S-Cluster Object (DSO/G2)
Authors: Shahzamanian Banafsheh , Eckart Andreas , Zajacek Michal , Valencia-S. Monica , Sabha Nadeen
Published: January 2018

There have been different scenarios describing the nature of a dusty source, noted as Dusty S-cluster Object (DSO) or G2, orbiting around the Galactic centre super-massive black hole. Observing the polarized continuum emission of this source provides information on its nature and geometry. We show that this source is intrinsically polarized with polarization degree of 30%, implying that it has a non-spherical geometry, and a varying polarization angle in the ambient medium of the black hole. Its main observable properties can be well described and modeled with a pre-main-sequence star forming a bow shock as it approaches the Sgr A* position.
Valuing Humans and Valuing Places: “Integrity” and the Preferred Terminology for Geoethics
Authors: Milligan Tony
Published: January 2018

What follows will support the centrality of appeals to the integrity of places as a plausible way of extending the concept of integrity in the light of our actual practices of valuing. The emphasis will, however, be upon practices of valuing rather than upon metaphysical claims about "inherent value”. The latter are not dismissed, they are merely set aside. The guiding thought is that our ethical theory should not depart too greatly from our understanding of how and what humans actually do hold to be of value in any particular culturally-shaped context. Following an introduction to the concept of integrity (Section 1), the discussion will open with an attempt to show that we do sometimes value places non-instrumentally (Section 2), even though we tend to look elsewhere to justify our respect for, and valuing of, places (Section 3). It will then proceed through a defence of appeals to such valuing as ethically significant (Section 4), before moving on to a provisional account of integrity as an effective way of making sense of what it is that we value when we value places in their own right (Section 5). Unlike Rolston, who is strongly associated with the concept of integrity, the intention is not to go metaphysically deep and identify something akin to the moral properties of things. Rather, the concern will be with the kinds of considerations that agents would typically point to as a reason for valuing places without any deeper set of claims about inherent value. This provides a less troubling, more metaphysically “neutral”, way of addressing matters. The paper is intended for an audience working on Geoethics; however, the norms of argument will be those associated more narrowly with philosophical ethics.
Acknowledgement to Reviewers of High-Throughput in 2017
Authors: Editorial Office High-Throughput
Published: January 2018

Peer review is an essential part in the publication process, ensuring that High-Throughput maintains high quality standards for its published papers [...]
Protective Factors in the Inuit Population of Nunavut: A Comparative Study of People Who Died by Suicide, People Who Attempted Suicide, and People Who Never Attempted Suicide
Authors: Beaudoin Véronique , Séguin Monique , Chawky Nadia , Affleck William , Chachamovich Eduardo , Turecki Gustavo
Published: January 2018

Epidemiological data shows an alarming prevalence of suicide in Aboriginal populations around the world. In Canada, the highest rates are found in Inuit communities. In this article, we present the findings of a secondary analysis conducted with data previously collected as part of a larger study of psychological autopsies conducted in Nunavut, Canada. The objective of this secondary analysis was to identify protective factors in the Inuit population of Nunavut by comparing people who died by suicide, people from the general population who attempted suicide, and people from the general population who never attempted suicide. This case-control study included 90 participants, with 30 participants in each group who were paired by birth date, sex, and community. Content analysis was first conducted on the clinical vignettes from the initial study in order to codify the presence of protective variables. Then, inferential analyses were conducted to highlight differences between each group in regards to protection. Findings demonstrated that (a) people with no suicide attempt have more protective variables throughout their lifespan than people who died by suicide and those with suicide attempts within the environmental, social, and individual dimensions; (b) people with suicide attempts significantly differ from the two other groups in regards to the use of services; and (c) protective factors that stem from the environmental dimension show the greatest difference between the three groups, being significantly more present in the group with no suicide attempt. Considering these findings, interventions could focus on enhancing environmental stability in Inuit communities as a suicide prevention strategy.
Transcriptional Regulation by CpG Sites Methylation in the Core Promoter Region of the Bovine SIX1 Gene: Roles of Histone H4 and E2F2
Authors: Wei Dawei , Li Anning , Zhao Chunping , Wang Hongbao , Mei Chugang , Khan Rajwali , Zan Linsen
Published: January 2018

DNA methylation is a major epigenetic modification of the genome and has an essential role in muscle development. The SIX1 gene is thought to play a principal role in mediating skeletal muscle development. In the present study, we determined that bovine SIX1 expression levels were significantly higher in the fetal bovine group (FB) and in undifferentiated Qinchuan cattle muscle cells (QCMCs) than in the adult bovine group (AB) and in differentiated QCMCs. Moreover, a bisulfite sequencing polymerase chain reaction (BSP) analysis of DNA methylation levels showed that three CpG sites in the core promoter region (−216/−28) of the bovine SIX1 gene exhibited significantly higher DNA methylation levels in the AB and differentiated QCMCs groups. In addition, we found that DNA methylation of SIX1 core promoter in vitro obviously influences the promoter activities. An electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay, in combination with site-directed mutation and siRNA interference, demonstrated that histone H4 and E2F2 bind to the −216/−28 region and play important roles in SIX1 methylation regulation during development. The results of this study provide the foundation for a better understanding of the regulation of bovine SIX1 expression via methylation and muscle developmental in beef cattle.
Numerical Analysis of CNC Milling Chatter Using Embedded Miniature MEMS Microphone Array System
Authors: Wang Pang-Li , Tsai Yu-Ting
Published: January 2018

With the increasingly common use of industrial automation for mass production, there are many computer numerical control (CNC) machine tools that require the collection of data from intelligent sensors in order to analyze their processing quality. In general, for high speed rotating machines, an accelerometer can be attached on the spindle to collect the data from the detected vibration of the CNC. However, due to their cost, accelerometers have not been widely adopted for use with typical CNC machine tools. This study sought to develop an embedded miniature MEMS microphone array system (Radius 5.25 cm, 8 channels) to discover the vibration source of the CNC from spatial phase array processing. The proposed method utilizes voice activity detection (VAD) to distinguish between the presence and absence of abnormal noise in the pre-stage, and utilizes the traditional direction of arrival method (DOA) via multiple signal classification (MUSIC) to isolate the spatial orientation of the noise source in post-processing. In the numerical simulation, the non-interfering noise source location is calibrated in the anechoic chamber, and is tested with real milling processing in the milling machine. As this results in a high background noise level, the vibration sound source is more accurate in the presented energy gradation graphs as compared to the traditional MUSIC method.
Evaluation of Underwater Image Enhancement Algorithms under Different Environmental Conditions
Authors: Mangeruga Marino , Cozza Marco , Bruno Fabio
Published: January 2018

Underwater images usually suffer from poor visibility, lack of contrast and colour casting, mainly due to light absorption and scattering. In literature, there are many algorithms aimed to enhance the quality of underwater images through different approaches. Our purpose was to identify an algorithm that performs well in different environmental conditions. We have selected some algorithms from the state of the art and we have employed them to enhance a dataset of images produced in various underwater sites, representing different environmental and illumination conditions. These enhanced images have been evaluated through some quantitative metrics. By analysing the results of these metrics, we tried to understand which of the selected algorithms performed better than the others. Another purpose of our research was to establish if a quantitative metric was enough to judge the behaviour of an underwater image enhancement algorithm. We aim to demonstrate that, even if the metrics can provide an indicative estimation of image quality, they could lead to inconsistent or erroneous evaluations.
Contaminant Particle Motion in Lubricating Grease Flow: A Computational Fluid Dynamics Approach
Authors: Westerberg Lars-Göran , Farré-Lladós Josep , Sarkar Chiranjit , Casals-Terré Jasmina
Published: January 2018

In this paper, numerical simulations of particle migration in lubricating grease flow are presented. The rheology of three lithium greases with NLGI (National Lubricating Grease Institute) grades 00, 1 and 2 respectively are considered. The grease is modeled as a single-phase Herschel–Bulkley fluid, and the particle migration has been considered in two different grease pockets formed between two concentric cylinders where the inner cylinder is rotating and driving the flow. In the wide grease pocket, the width of the gap is much smaller compared to the axial length scale, enabling a one-dimensional flow. In the narrow pocket, the axial and radial length is of the same order, yielding a three-dimensional flow. It was found that the change in flow characteristics due to the influence of the pocket lateral boundaries when going from the wide to the narrow pocket leads to a significantly shorter migration time. Comparing the results with an existing migration model treating the radial component contribution, it was concluded that a solution to the flow in the whole domain is needed together with a higher order numerical scheme to obtain a full solution to the particle migration. This result is more pronounced in the narrow pocket due to gradients in the flow induced by the lateral boundaries.
Modeling of Dynamic Behavior of Carbon Fiber-Reinforced Polymer (CFRP) Composite under X-ray Radiation
Authors: Zhang Kun , Tang Wenhui , Fu Kunkun
Published: January 2018

Carbon fiber-reinforced polymer (CFRP) composites have been increasingly used in spacecraft applications. Spacecraft may encounter highenergy-density X-ray radiation in outer space that can cause severe damage. To protect spacecraft from such unexpected damage, it is essential to predict the dynamic behavior of CFRP composites under X-ray radiation. In this study, we developed an in-house three-dimensional explicit finite element (FEM) code to investigate the dynamic responses of CFRP composite under X-ray radiation for the first time, by incorporating a modified PUFF equation-of-state. First, the blow-off impulse (BOI) momentum of an aluminum panel was predicted by our FEM code and compared with an existing radiation experiment. Then, the FEM code was utilized to determine the dynamic behavior of a CFRP composite under various radiation conditions. It was found that the numerical result was comparable with the experimental one. Furthermore, the CFRP composite was more effective than the aluminum panel in reducing radiation-induced pressure and BOI momentum. The numerical results also revealed that a 1 keV X-ray led to vaporization of surface materials and a high-magnitude compressive stress wave, whereas a low-magnitude stress wave was generated with no surface vaporization when a 3 keV X-ray was applied.
Characterization of an Additive Manufactured TiAl Alloy—Steel Joint Produced by Electron Beam Welding
Authors: Basile Gloria , Baudana Giorgio , Marchese Giulio , Lorusso Massimo , Lombardi Mariangela , Ugues Daniele , Fino Paolo , Biamino Sara
Published: January 2018

In this work, the characterization of the assembly of a steel shaft into a γ-TiAl part for turbocharger application, obtained using Electron Beam Welding (EBW) technology with a Ni-based filler, was carried out. The Ti-48Al-2Nb-0.7Cr-0.3Si (at %) alloy part was produced by Electron Beam Melting (EBM). This additive manufacturing technology allows the production of a lightweight part with complex shapes. The replacement of Nickel-based superalloys with TiAl alloys in turbocharger automotive applications will lead to an improvement of the engine performance and a substantial reduction in fuel consumption and emission. The welding process allows a promising joint to be obtained, not affecting the TiAl microstructure. Nevertheless, it causes the formation of diffusive layers between the Ni-based filler and both steel and TiAl, with the latter side being characterized by a very complex microstructure, which was fully characterized in this paper by means of Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, and nanoindentation. The diffusive interface has a thickness of about 6 µm, and it is composed of several layers. Specifically, from the TiAl alloy side, we find a layer of Ti3Al followed by Al3NiTi2 and AlNi2Ti. Subsequently Ni becomes more predominant, with a first layer characterized by abundant carbide/boride precipitation, and a second layer characterized by Si-enrichment. Then, the chemical composition of the Ni-based filler is gradually reached.
Comparisons of Different Models on Dynamic Recrystallization of Plate during Asymmetrical Shear Rolling
Authors: Zhang Tao , Li Lei , Lu Shi-Hong , Gong Hai , Wu Yun-Xin
Published: January 2018

Asymmetrical shear rolling with velocity asymmetry and geometry asymmetry is beneficial to enlarge deformation and refine grain size at the center of the thick plate compared to conventional symmetrical rolling. Dynamic recrystallization (DRX) plays a vital role in grain refinement during hot deformation. Finite element models (FEM) coupled with microstructure evolution models and cellular automata models (CA) are established to study the microstructure evolution of plate during asymmetrical shear rolling. The results show that a larger DRX fraction and a smaller average grain size can be obtained at the lower layer of the plate. The DRX fraction at the lower part increases with the ascending speed ratio, while that at upper part decreases. With the increase of the offset distance, the DRX fraction slightly decreases for the whole thickness of the plate. The differences in the DRX fraction and average grain size between the upper and lower surfaces increase with the ascending speed ratio; however, it varies little with the change of the speed ratio. Experiments are conducted and the CA models have a higher accuracy than FEM models as the grain morphology, DRX nuclei, and grain growth are taken into consideration in CA models, which are more similar to the actual DRX process during hot deformation.
Fabrication, Structural Characterization and Uniaxial Tensile Properties of Novel Sintered Multi-Layer Wire Mesh Porous Plates
Authors: Duan Liuyang , Zhou Zhaoyao , Yao Bibo
Published: January 2018

There is an increasing interest in developing porous metals or metallic foams for functional and structural applications. The study of the physical and mechanical properties of porous metals is very important and helpful for their application. In this paper, a novel sintered multilayer wire mesh porous plate material (WMPPs) with a thickness of 0.5 mm–3 mm and a porosity of 10–35% was prepared by winding, pressing, rolling, and subsequently vacuum sintering them. The pore size and total size distribution in the as-prepared samples were investigated using the bubble point method. The uniaxial tensile behavior of the WMPPs was investigated in terms of the sintering temperature, porosity, wire diameter, and manufacturing technology. The deformation process and the failure mechanism under the tensile press was also discussed based on the appearance of the fractures (SEM figures). The results indicated that the pore size and total size distribution were closely related to the raw material used and the sintering temperature. For the WMPPs prepared by the wire mesh, the pore structures were inerratic and the vast majority of pore size was less than 10 μm. On the other hand, for the WMPPs that were prepared by wire mesh and powder, the pore structures were irregular and the pore size ranged from 0 μm–50 μm. The experimental data showed that the tensile strength of WMPPs is much higher than any other porous metals or metallic foams. Higher sintering temperatures led to coarser joints between wires and resulted in higher tensile strength. The sintering temperature decreased from 1330 °C to 1130 °C and the tensile strength decreased from 296 MPa to 164 MPa. Lower porosity means that there are more metallurgical joints and metallic frameworks resisting deformation per unit volume. Therefore, lower porosities exhibit higher tensile strength. An increase of porosity from 17.14% to 32.5% led to the decrease of the tensile strength by 90 MPa. The coarser wires led to a bigger contact area between the interconnecting wires, resulting in a stronger sintering neck that exhibited higher tensile strength. The wire diameter increased from 81 μm to 122 μm and the tensile strength increased from 296 MPa to 362 MPa. The fracture morphology showed that the wires experience necking deformation and ductile fracture.
Acknowledgement to Reviewers of Machines in 2017
Authors:   Machines Editorial Office
Published: January 2018

The editors of Machines would like to express their sincere gratitude to the following reviewers for assessing manuscripts in 2017.[...]
Best Approximation of the Fractional Semi-Derivative Operator by Exponential Series
Authors: Zakharchenko Vladimir , Kovalenko Ilya
Published: January 2018

A significant reduction in the time required to obtain an estimate of the mean frequency of the spectrum of Doppler signals when seeking to measure the instantaneous velocity of dangerous near-Earth cosmic objects (NEO) is an important task being developed to counter the threat from asteroids. Spectral analysis methods have shown that the coordinate of the centroid of the Doppler signal spectrum can be found by using operations in the time domain without spectral processing. At the same time, an increase in the speed of resolving the algorithm for estimating the mean frequency of the spectrum is achieved by using fractional differentiation without spectral processing. Thus, an accurate estimate of location of the centroid for the spectrum of Doppler signals can be obtained in the time domain as the signal arrives. This paper considers the implementation of a fractional-differentiating filter of the order of ½ by a set of automation astatic transfer elements, which greatly simplifies practical implementation. Real technical devices have the ultimate time delay, albeit small in comparison with the duration of the signal. As a result, the real filter will process the signal with some error. In accordance with this, this paper introduces and uses the concept of a “pre-derivative” of ½ of magnitude. An optimal algorithm for realizing the structure of the filter is proposed based on the criterion of minimum mean square error. Relations are obtained for the quadrature coefficients that determine the structure of the filter.
Mathematical Modeling of Drag Coefficient Reduction in Circular Cylinder Using Two Passive Controls at Re = 1000
Authors: Imron Chairul , Mardianto Lutfi , Widodo Basuki , Yuwono Tri
Published: January 2018

One of the many ways to reduce drag force is by adding a small object called passive control. Two passive controls will be placed in front and at the rear of the main object. The main object used is a circular cylinder, and the passive controls used are the Type-I cylinder in the front and an elliptical cylinder at the rear of the main object. The distances between the main object and the passive controls are varied. The Reynolds number used is 1000. The effective distance between the main object and the passive controls is analyzed by using the mathematical model so that the drag coefficient on the main object is compared with the simulated one.
Acknowledgement to Reviewers of MCA in 2017
Authors:   MCA Editorial Office
Published: January 2018

Peer review is an essential part in the publication process, ensuring that MCA (Mathematical and Computational Applications) maintains high quality standards for its published papers.[...]
Low Molecular Weight Chitosan-Insulin Complexes Solubilized in a Mixture of Self-Assembled Labrosol and Plurol Oleaque and Their Glucose Reduction Activity in Rats
Authors: Elsayed Amani , Khaled Aseel , Al Remawi Mayyas , Qinna Nidal , Abu Farsakh Hussam , Badwan Adnan
Published: January 2018

Oral insulin delivery that better mimics physiological pathways is a necessity as it ensures patient comfort and compliance. A system which is based on a vehicle of nano order where positively charged chitosan interacts with negatively charged insulin and forms a polyelectrolyte complex (PEC) solubilizate, which is then solubilized into an oily phase of oleic acid, labrasol, and plurol oleaque-protects insulin against enzymatic gastrointestinal reduction. The use of an anionic fatty acid in the oily phase, such as oleic acid, is thought to allow an interaction with cationic chitosan, hence reducing particle size. Formulations were assessed based on their hypoglycaemic capacities in diabetic rats as compared to conventional subcutaneous dosage forms. 50 IU/kg oral insulin strength could only induce blood glucose reduction equivalent to that of 5 IU/kg (1 International unit = 0.0347 mg of human insulin). Parameters that influence the pharmacological availability were evaluated. A preliminary investigation of the mechanism of absorption suggests the involvement of the lymphatic route.
Announcing the 2018 Medicines Travel Award for PostDocs
Authors: Litscher Gerhard
Published: January 2018

For the Medicines Travel Award 2018, we received a total of 41 applications from all over the world, of a wery high quality[...]
Acknowledgement to Reviewers of Micromachines in 2017
Authors:   Micromachines Editorial Office
Published: January 2018

Peer review is an essential part in the publication process, ensuring that Micromachines maintains high quality standards for its published papers.[...]
Pair Interaction of Catalytical Sphere Dimers in Chemically Active Media
Authors: Shi Jing-Min , Cui Ru-Fei , Xiao Jie , Qiao Li-Yan , Mao Jun-Wen , Chen Jiang-Xing
Published: January 2018

We study the pair dynamics of two self-propelled sphere dimers in the chemically active medium in which a cubic autocatalytic chemical reaction takes place. Concentration gradient around the dimer, created by reactions occurring on the catalytic sphere surface and responsible for the self-propulsion, is greatly influenced by the chemical activities of the environment. Consequently, the pair dynamics of two dimers mediated by the concentration field are affected. In the particle-based mesoscopic simulation, we combine molecular dynamics (MD) for potential interactions and reactive multiparticle collision dynamics (RMPC) for solvent flow and bulk reactions. Our results indicate three different configurations between a pair of dimers after the collision, i.e., two possible scenarios of bound dimer pairs and one unbound dimer pair. A phase diagram is sketched as a function of the rate coefficients of the environment reactions. Since the pair interactions are the basic elements of larger scale systems, we believe the results may shed light on the understanding of the collective dynamics.