bluuebunny/crossref_metadata_2025 huggingface dataset:
Oligomerization of Butene Mixture over NiO/Mesoporous Aluminosilicate Catalyst
Authors: Lee Donggun , Kim Hyeona , Park Young-Kwon , Jeon Jong-Ki
Published: October 2018

This study is aimed at preparing C8–C16 alkene through oligomerization of a butene mixture using nickel oxide supported on mesoporous aluminosilicate. Mesoporous aluminosilicate with an ordered structure was successfully synthesized from HZSM-5 zeolite by combining a top-down and a bottom-up method. MMZZSM-5 catalyst showed much higher butene conversion and C8–C16 yield in the butene oligomerization reaction than those with HZSM-5. This is attributed to the pore geometry of MMZZSM-5, which is more beneficial for internal diffusion of reactants, reaction intermediates, and products. The ordered channel-like mesopores were maintained after the nickel-loading on MMZZSM-5. The yield for C8–C16 hydrocarbons over NiO/MMZZSM-5 was higher than that of MMZZSM-5 catalyst, which seemed to be due to higher acid strength from a higher ratio of Lewis acid to Brønsted acid. The present study reveals that a mesoporous NiO/MMZZSM-5 catalyst with a large amount of Lewis acid sites is one of the potential catalysts for efficient generation of aviation fuel through the butene oligomerization.
Samp1 Mislocalization in Emery-Dreifuss Muscular Dystrophy
Authors: Mattioli Elisabetta , Columbaro Marta , Jafferali Mohammed Hakim , Schena Elisa , Hallberg Einar , Lattanzi Giovanna
Published: October 2018

LMNA linked-Emery-Dreifuss muscular dystrophy (EDMD2) is a rare disease characterized by muscle weakness, muscle wasting, and cardiomyopathy with conduction defects. The mutated protein lamin A/C binds several nuclear envelope components including the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex and the inner nuclear membrane protein Samp1 (Spindle Associated Membrane Protein 1). Considering that Samp1 is upregulated during muscle cell differentiation and it is involved in nuclear movement, we hypothesized that it could be part of the protein platform formed by LINC proteins and prelamin A at the myotube nuclear envelope and, as previously demonstrated for those proteins, could be affected in EDMD2. Our results show that Samp1 is uniformly distributed at the nuclear periphery of normal human myotubes and committed myoblasts, but its anchorage at the nuclear poles is related to the presence of farnesylated prelamin A and it is disrupted by the loss of prelamin A farnesylation. Moreover, Samp1 is absent from the nuclear poles in EDMD2 myotubes, which shows that LMNA mutations associated with muscular dystrophy, due to reduced prelamin A levels in muscle cell nuclei, impair Samp1 anchorage. Conversely, SUN1 pathogenetic mutations do not alter Samp1 localization in myotubes, which suggests that Samp1 lies upstream of SUN1 in nuclear envelope protein complexes. The hypothesis that Samp1 is part of the protein platform that regulates microtubule nucleation from the myotube nuclear envelope in concert with pericentrin and LINC components warrants future investigation. As a whole, our data identify Samp1 as a new contributor to EDMD2 pathogenesis and our data are relevant to the understanding of nuclear clustering occurring in laminopathic muscle.
Advancements and Potential Applications of Microfluidic Approaches—A Review
Authors: Ahmed Ishtiaq , Akram Zain , Bule Mohammed Hussen , Iqbal Hafiz M. N.
Published: October 2018

A micro-level technique so-called “microfluidic technology or simply microfluidic” has gained a special place as a powerful tool in bioengineering and biomedical engineering research due to its core advantages in modern science and engineering. Microfluidic technology has played a substantial role in numerous applications with special reference to bioscience, biomedical and biotechnological research. It has facilitated noteworthy development in various sectors of bio-research and upsurges the efficacy of research at the molecular level, in recent years. Microfluidic technology can manipulate sample volumes with precise control outside cellular microenvironment, at micro-level. Thus, enable the reduction of discrepancies between in vivo and in vitro environments and reduce the overall reaction time and cost. In this review, we discuss various integrations of microfluidic technologies into biotechnology and its paradigmatic significance in bio-research, supporting mechanical and chemical in vitro cellular microenvironment. Furthermore, specific innovations related to the application of microfluidics to advance microbial life, solitary and co-cultures along with a multiple-type cell culturing, cellular communications, cellular interactions, and population dynamics are also discussed.
Exact Solutions and Degenerate Properties of Spin Chains with Reducible Hamiltonians
Authors: Fan Shiung
Published: October 2018

The Jordan–Wigner transformation plays an important role in spin models. However, the non-locality of the transformation implies that a periodic chain of N spins is not mapped to a periodic or an anti-periodic chain of lattice fermions. Since only the N − 1 bond is different, the effect is negligible for large systems, while it is significant for small systems. In this paper, it is interesting to find that a class of periodic spin chains can be exactly mapped to a periodic chain and an anti-periodic chain of lattice fermions without redundancy when the Jordan–Wigner transformation is implemented. For these systems, possible high degeneracy is found to appear in not only the ground state, but also the excitation states. Further, we take the one-dimensional compass model and a new XY-XY model ( σ x σ y − σ x σ y ) as examples to demonstrate our proposition. Except for the well-known one-dimensional compass model, we will see that in the XY-XY model, the degeneracy also grows exponentially with the number of sites.
Endocrine Disruption by Mixtures in Topical Consumer Products
Authors: Ripamonti Emiliano , Allifranchini Elena , Todeschi Stefano , Bocchietto Elena
Published: October 2018

Endocrine disruption has been gathering increasing attention in the past 25 years as a possible new threat for health and safety. Exposure to endocrine disruptor has been progressively linked with a growing number of increasing disease in the human population. The mechanics through which endocrine disruptors act are not yet completely clear, however a number of pathways have been identified. A key concern is the cumulative and synergic effects that endocrine disruptors could have when mixed in consumer products. We reviewed the available literature to identify known or potential endocrine disruptors, as well as endocrine active substances that could contribute to cumulative effects, in topical consumer products. The number of endocrine actives used daily in consumer products is staggering and even though most if not all are used in concentrations that are considered to be safe, we believe that the possibility of combined effects in mixtures and non-monotonic dose/response is enough to require further precautions. A combined in vitro approach based on existing, validated OECD test methods is suggested to screen consumer products and mixtures for potential interaction with estrogen and androgen hormone receptors, in order to identify products that could have cumulative effects or support their safety concerning direct endocrine disruption capabilities.
Refolding, Characterization, and Preliminary X-ray Crystallographic Studies on the Campylobacter concisus Plasmid-Encoded Secreted Protein Csep1p Associated with Crohn’s Disease
Authors: Rahman Mohammad , Goff Bradley , Zhang Li , Roujeinikova Anna
Published: October 2018

Colonization of Campylobacter concisus in the gastrointestinal tract can lead to the development of inflammatory bowel disease (IBD). Plasmid-encoded C. concisus-secreted protein 1 (Csep1p) was recently identified as a putative pathogenicity marker associated with active Crohn’s disease, a clinical form of IBD. Csep1p shows no significant full-length sequence similarity to proteins of known structure, and its role in pathogenesis is not yet known. This study reports a method for extraction of recombinantly expressed Csep1p from Escherichia coli inclusion bodies, refolding, and purification to produce crystallizable protein. Purified recombinant Csep1p behaved as a monomer in solution. Crystals of Csep1p were grown by the hanging drop vapour diffusion method, using polyethylene glycol (PEG) 4000 as the precipitating agent. A complete data set has been collected to 1.4 Å resolution, using cryocooling conditions and synchrotron radiation. The crystals belong to space group P62 or P64, with unit cell parameters a = b = 85.8, c = 55.2 Å, α = β = 90, and γ = 120°. The asymmetric unit appears to contain one subunit, corresponding to a packing density of 2.47 Å3 Da−1.
18 F-FDG PET/CT in Extensive Graft-Versus-Host Disease of the Gastrointestinal Tract Following Autologous Stem Cell Transplantation
Authors: Dejanovic Danijela , Amtoft Annemarie , Loft Annika
Published: October 2018

Graft-versus-host-disease (GVHD) following stem cell transplantation (SCT) is a common complication in patients that have undergone allogenic SCT but rare in recipients of autologous SCT. Gastro-intestinal tract (GIT)-GVHD can be difficult to diagnose due to non-specific symptoms such as fever, nausea, diarrhea, and vomiting; a histological confirmation is therefore required. Here, we present the findings of a whole-body 18FDG PET/CT with extensive and multifocal involvement of the GIT in a patient that developed severe acute GVHD 93 days post autologous SCT for Hodgkin’s lymphoma. PET and CT findings included characteristic patterns of bowel inflammation with bowel wall thickening, mural stratification and enhancement with high FDG-uptake of the involved regions, as well as typical extra intestinal findings such as ascites, engorgement of the vasa recti and stranding of the mesenteric fat. Although, the above-mentioned findings are not exclusive to GIT-GVHD and can be seen in other settings of inflammatory bowel disease such as enterocolitis or Mb Crohn our findings were used for targeted biopsy that confirmed acute GIT-GVHD. This case demonstrates that 18F-FDG-PET/CT can be a valuable non-invasive tool in mapping the activity and distribution of intestinal GVHD and direct for targeted biopsies of involved regions.
How to Teach Heat Transfer More Systematically by Involving Entropy
Authors: Herwig Heinz
Published: October 2018

In order to teach heat transfer systematically and with a clear physical background, it is recommended that entropy should not be ignored as a fundamental quantity. Heat transfer processes are characterized by introducing the so-called “entropic potential” of the transferred energy, and an assessment number is based on this new quantity.
Estimated Reaction Force-Based Bilateral Control between 3DOF Master and Hydraulic Slave Manipulators for Dismantlement
Authors: Kallu Karam Dad , Wang Jie , Abbasi Saad Jamshed , Lee Min Cheol
Published: October 2018

This paper proposes a novel bilateral control design based on an estimated reaction force without a force sensor for a three-degree of freedom hydraulic servo system with master–slave manipulators. The proposed method is based upon sliding mode control with sliding perturbation observer (SMCSPO) using a bilateral control environment. The sliding perturbation observer (SPO) estimates the reaction force at the end effector and second link without using any sensors. The sliding mode control (SMC) is used as a bilateral controller for the robust position tracking and control of the slave device. A bilateral control strategy in a hydraulic servo system provides robust position and force tracking between master and slave. The difference between the reaction force of the slave produced by the effect of the remote environment and the operating force applied to the master by the operator is expressed in the target impedance model. The impedance model is applied to the master and allows the operator to feel the reaction force from the environment. This research experimentally verifies that the slave device can follow the trajectory of the master device using the proposed bilateral control strategy based on the estimated reaction force. This technique will be convenient for three or more degree of freedom (DOF) hydraulic servo systems used in dismantling nuclear power plants. It is worthy to mention that a camera is used for visual feedback on the safety of the environment and workspace.
Flux-Switching Permanent Magnet Machine with Phase-Group Concentrated-Coil Windings and Cogging Torque Reduction Technique
Authors: Kwon Jung-Woo , Lee Jin-hee , Zhao Wenliang , Kwon Byung-Il
Published: October 2018

We herein propose a novel high-torque-density flux-switching permanent magnet machine (FSPMM) which adopted phase-group concentrated-coil (PGCC) winding and a cogging torque reduction technique. The PGCC winding was applied to increase the torque density. In order to maximize the torque of the FSPMM that utilizes the PGCC windings, the performance according to stator slots/rotor poles combinations were compared. A machine which had 12 stator slots and 13 rotor poles (12S13P) was selected for its top average torque value. However, the 12S13P PGCC FSPMM contains high cogging torque that must be reduced. The cogging torque reduction technique is applied, and the parameters used in the technique are further optimized to achieve the target average torque, while suppressing the cogging torque as much as possible. The optimization process was performed with a collaboration of the genetic algorithm and Kriging method. The analysis results of the optimized design exhibited huge reductions in the cogging torque and eventually in the torque ripple from the initial machine, with reasonable average torque reduction. The entire work was evaluated experimentally using a manufactured prototype.
Wind Micro-Turbine Networks for Urban Areas: Optimal Design and Power Scalability of Permanent Magnet Generators
Authors: Palmieri Marco , Bozzella Salvatore , Cascella Giuseppe Leonardo , Bronzini Marco , Torresi Marco , Cupertino Francesco
Published: October 2018

This work is focused on the design optimization of electrical machines that are used in small-scale direct-drive aerogenerators. A ducted wind turbine, equipped with a diffuser, is considered due to its enhanced power capability with respect to bare turbines. An annular type Permanent Magnet brushless generator is integrated in the turbine structure: the stator coils are placed in the internal part of the diffuser, whereas the permanent magnets are on an external ring connected to the turbine blade tips. Moreover, as regards the stator windings, the Printed Circuit Board (PCB) technology is investigated in order to exploit its advantages with respect to conventional wire coils, such as the increased current density capacity, the reduction of costs, and the enhanced precision and repeatability of the PCBs. An original design procedure is presented together with some scalability rules. An automated tool has been developed in order to aid the electrical machine designer in the first design stages: the tool performs multi-objective optimizations (using the Matlab Genetic Algorithm Toolbox), coupled to fast Finite Element analysis (through the open-source software FEMM) for the evaluation of the electromagnetic torque and field distribution. The proposed procedure is applied to the design of an annular PM generator directly coupled to a small-scale turbine for an urban application.
Influence of High Loading on the Performance of Natural Graphite-Based Al Secondary Batteries
Authors: Huang Mao-Chia , Yang Cheng-Hsien , Chiang Chien-Chih , Chiu Sheng-Cheng , Chen Yun-Feng , Lin Cong-You , Wang Lu-Yu , Li Yen-Liang , Yang Chang-Chung , Chang Wen-Sheng
Published: October 2018

In recent years, novel Al secondary batteries with Al anodes, natural graphite cathodes, and ionic liquid electrolytes have received more attention. However, most research on Al secondary batteries used lower graphite loading (<8 mg/cm2), which will inhibit the batteries from commercialization in the future. Here, we prepared Al secondary batteries using Al anode, low-cost natural graphite cathode, and cheaper ionic liquid electrolyte. The effects of loading (7–12 mg/cm2) on performance were investigated. Based on our observations, graphite-based Al secondary batteries (GABs) using 10 mg/cm2 graphite electrodes had better performance of 82 mAh/g and 6.5 Wh/L at a current density of 100 mA/g. Moreover, the 10 mg/cm2 GABs showed a long life of 250 charge–discharge cycles with a high coulombic efficiency of 98% and excellent performance rate up to 1000 mA/g.
Control of Current Phase Advancing in Single-Leg Power Converters with the Use of Switched Capacitors
Authors: Konarik Roman , Sedo Jozef , Dobrucky Branislav , Prazenica Michal
Published: October 2018

This paper deals with the control of current phase advancing in single-leg voltage source inverters (VSI) and matrix converters with a two-phase output. The phase shift of the current in the auxiliary phase is set with the use of switched capacitors. Two distinctive control methods are used for the current phase advancing, open-loop control and closed-loop control. In addition, a new averaging method is derived for the calculation of the switched capacitance used in the open-loop control. The practical use of the designed control methods with the switched capacitor is shown in simulations and experimental verifications on a single-leg matrix converter with a passive and active load (induction motor).
Application of Thermal Labyrinth System to Reduce Heating and Cooling Energy Consumption
Authors: Rim Minyeop , Sung Uk-Joo , Kim Taeyeon
Published: October 2018

To reduce the energy consumption in buildings, modern buildings are increasingly becoming airtight. In these structures, the outdoor air is supplied inside through mechanical ventilation systems, which are essential for ensuring comfortable indoor air quality. However, these systems consume a considerable amount of energy in buildings. One potential solution is using a thermal labyrinth system, which is buried underneath the building. It can pre-cool or pre-heat the outdoor air through heat transfer with the surrounding soil. In this research, a number of case studies were conducted to optimize the thermal labyrinth design. The optimized thermal labyrinth system was derived using computational fluid dynamics (CFD) simulation. In addition, operation algorithms were developed for the efficient operation of the thermal labyrinth system in buildings. The results indicated that there were five operation modes, and the thermal labyrinth could be operated for seven months of the year. The energy reduction effects of the thermal labyrinth system were analyzed and were assessed by the transient system simulation (TRNSYS) tool. A 12% reduction in the annual heating and cooling energy was achieved by applying the thermal labyrinth system.
Ultra-Short-Term Wind Power Prediction Based on Multivariate Phase Space Reconstruction and Multivariate Linear Regression
Authors: Liu Rongsheng , Peng Minfang , Xiao Xianghui
Published: October 2018

In order to improve the accuracy of wind power prediction (WPP), we propose a WPP based on multivariate phase space reconstruction (MPSR) and multivariate linear regression (MLR). Firstly, the multivariate time series (TS) are constructed through reasonable selection of wind power and weather factors, which are closely associated with wind power. Secondly, the phase space of the multivariate time series is reconstructed based on the chaos theory and C-C method. Thirdly, an auto regression model for multivariate phase space is created by regarding phase variables as state variables, and the very-short-term wind power is predicted by using a multi-linear regression algorithm. Finally, a parallel algorithm based on map/reduce is presented to improve computing speed. A cloud computing platform, Hadoop consisting of five nodes, is established as a matter of convenience, followed by the prediction of wind power of a wind farm in the Hunan province of China. The experimental results show that the model based on MPSR and MLR is more accurate than both the continuous method and the simple approximation method, and the parallel algorithm based on map/reduce effectively accelerates the computing speed.
Aspects of Heat Supply Security Management Using Elements of Decision Theory
Authors: Babiarz Bożena
Published: October 2018

Security in heat supply systems plays an important role in social, technical and political terms. It includes three main components: energy security, security of heat supply, security of people. The differences concern the subject, area, scope, as well as the degree and purpose of the analyses. The article is a continuation of research conducted by the author, presenting the concept of security of heat supply as a necessary “umbrella” supported by reliability and system resilience to threats, constituting a set of actions aimed at minimizing the risk. The subject of the analysis of this article is the security of heat supply, analysed in the context of heat supply management to recipients and risk analysis related to the lack of heat supply. The elements of decision theory were used as adequate for this purpose. Different configurations of heat distribution in the system have been taken into account when determining the expected values of risk related to the occurrence of power limitation for various degrees of restrictions and various network configurations. The author’s use of elements of decision theory in heat supply systems illustrated at the work gives the opportunity to assess and manage the security of heat supply to the recipient. It takes into account the possibility of different heat distribution configurations in the system at the operational stage, as well as may be the basis for optimizing changes in the distribution of power supply areas and selecting the most advantageous network configuration at the design stage.
On the Potential of Power Generation from Thermoelectric Generators in Gas Turbine Combustors
Authors: Stathopoulos Panagiotis , Fernàndez-Villa Javier
Published: October 2018

Thermoelectric generators (TEGs) offer an attractive power generation option. They have no moving parts, are robust and emit no pollutants. The current work explores the integration of high temperature TEGs in gas turbine combustors. The latter have a thermal shield at their inner surface to protect them against high temperatures. This is supplemented by convective and film cooling. This work studies the replacement of the thermal shield with high temperature TEGs and evaluates their techno-economic potential. A gas turbine model is developed and validated to compute the fuel and air flow rate in the combustion chamber. A heat transfer model is subsequently implemented to compute the temperature distribution inside the combustor wall, on which the TEG is constructed. The investment in TEGs is then analyzed for peaker, intermediate load and base load gas turbines. The work concludes with a sensitivity analysis of the investment economic performance. It is concluded that, despite the low power generation, the installation of TEGs makes economic sense, even if their price becomes 50% higher than current estimations. It is also concluded that electricity prices have a much stronger effect on the economic viability of the investment than the price of the generators.
Separation of Acetate Produced from C1 Gas Fermentation Using an Electrodialysis-Based Bioelectrochemical System
Authors: Baek Jiyun , Kim Changman , Song Young Eun , Im Hyeon Sung , Sakuntala Mutyala , Kim Jung Rae
Published: October 2018

The conversion of C1 gas feedstock, such as carbon monoxide (CO), to useful platform chemicals has attracted considerable interest in industrial biotechnology. One conversion method is electrode-based electron transfer to microorganisms using bioelectrochemical systems (BESs). In this BES system, acetate is the predominant component of various volatile fatty acids (VFAs). To appropriately separate and concentrate the acetate produced, a BES-type electrodialysis cell with an anion exchange membrane was constructed and evaluated under various operational conditions, such as applied external current, acetate concentration, and pH. A high acetate flux of 23.9 mmol/m2∙h was observed under a −15 mA current in an electrodialysis-based bioelectrochemical system. In addition, the initial acetate concentration affected the separation efficiency and transportation rate. The maximum flux appeared at 48.6 mmol/m2∙h when the acetate concentration was 100 mM, whereas the effects of the initial pH of the anolyte were negligible. The acetate flux was 14.9 mmol/m2∙h when actual fermentation broth from BES-based CO fermentation was used as a catholyte. A comparison of the synthetic broth with the actual fermentation broth suggests that unknown substances and metabolites produced from the previous bioconversion process interfere with electrodialysis. These results provide information on the optimal conditions for the separation of VFAs produced by C1 gas fermentation through electrodialysis and a combination of a BES and electrodialysis.
Prediction of the Maximum Erosion Rate of Gas–Solid Two-Phase Flow Pipelines
Authors: Xu Jingyuan , Lian Zhanghua , Hu Jian , Luo Min
Published: October 2018

Erosion is one of the important reasons for the thickness decrease and perforation of the pipe walls. Understanding the gas–solid two-phase flow pipe erosion mechanism is the basis for monitoring pipe erosion. According to the structural characteristics and working conditions of the gas–solid two-phase flow pipeline in a gas transmission station, a gas–solid two-phase flow pipe erosion finite element model was established and validated by combining it with field test data. Then, the gas–solid two-phase flow pipeline erosion characteristics under different pressures, solid contents, throttle valve openings, and pipe diameters were studied. On this basis, a maximum erosion rate prediction equation was put forward after verification by using actual wall thickness detection data. Results show the following: (1) The absolute error of the maximum erosion rate between the model results and the test datum is ≤10.75%. (2) The outer cambered surface of the bend after the throttle valve is the most seriously eroded areas. (3) The maximum erosion rate increases with pressure, solid content and throttle valve opening increasing, but, along with the change of the pipe diameter, the maximum erosion rate increases at first and then decreases with pipe diameter increasing for throttle valve openings of 20% and 30%, and it decreases with pipe diameter increasing for a throttle valve opening of 50%. (4) A maximum erosion rate prediction equation, involving pressure, solid content, opening of the throttle valve, and pipe diameter, is proposed and is verified that the absolute percentage error between the prediction equation calculation results and the field test datum is ≤11.11%. It would seem that this maximum erosion rate prediction equation effectively improves the accuracy of predicting the gas–solid two-phase flow pipe erosion rate in a gas transmission station.
Fast Power Reserve Emulation Strategy for VSWT Supporting Frequency Control in Multi-Area Power Systems
Authors: Fernández-Guillamón Ana , Vigueras-Rodríguez Antonio , Gómez-Lázaro Emilio , Molina-García Ángel
Published: October 2018

The integration of renewables into power systems involves significant targets and new scenarios with an important role for these alternative resources, mainly wind and PV power plants. Among the different objectives, frequency control strategies and new reserve analysis are currently considered as a major concern in power system stability and reliability studies. This paper aims to provide an analysis of multi-area power systems submitted to power imbalances, considering a high wind power penetration in line with certain European energy road-maps. Frequency control strategies applied to wind power plants from different areas are studied and compared for simulation purposes, including conventional generation units. Different parameters, such as nadir values, stabilization time intervals and tie-line active power exchanges are also analyzed. Detailed generation unit models are included in the paper. The results provide relevant information on the influence of multi-area scenarios on the global frequency response, including participation of wind power plants in system frequency control.
Unbalanced Current Sharing Control in Islanded Low Voltage Microgrids
Authors: Najafi Foad , Hamzeh Mohsen , Fripp Matthias
Published: October 2018

This paper reports a new control strategy to improve sharing of unbalanced currents in islanded LV microgrids. This technique provides fast and effective sharing of positive-, negative- and zero-sequence currents, and is the first example of zero-sequence current sharing in the literature. The controllers are designed in the stationary frame. The control structure consists of four loops: (1) the current controller; (2) the voltage controller; (3) the droop controller and the (4) negative and zero sequence current controllers. The output current is considered unknown for the controller and is added to the control system as a disturbance. The proposed controller features a high gain in fundamental and harmonic frequencies, hence a good voltage quality is obtained in the presence of unbalanced and nonlinear loads. To this aim, a proportional-resonant (PR) controller is adopted as the current controller. By using a multi-resonant controller as current controller, a unified control structure is obtained which is suitable for both grid-connected and islanded modes. The voltage controller is designed using a resonant controller so that the voltage can have low VUF and THD in the presence of unbalanced and nonlinear loads. Furthermore, in this paper, the droop method is applied to the control structure to share real and reactive powers. Simulation studies show that the conventional droop method cannot share the oscillatory part of the output power that is due to the presence of unbalanced loads in the microgrid. This paper relies on using zero and negative sequence virtual impedance controller to share the oscillatory part of output power. By using zero-sequence virtual impedance controller (ZSVIC) and negative-sequence virtual impedance controller (NSVIC), the zero and negative sequence currents in the microgrid are controlled and shared effectively. By compensating zero- and negative-sequence currents locally, the flow of these currents in the microgrid is minimized, and the overall power quality of the islanded LV microgrid is improved.
A Short-Term Wind Speed Forecasting Model by Using Artificial Neural Networks with Stochastic Optimization for Renewable Energy Systems
Authors: Huang Chiou-Jye , Kuo Ping-Huan
Published: October 2018

To efficiently manage unstable wind power generation, precise short-term wind speed forecasting is critical. To overcome the challenges in wind speed forecasting, this paper proposes a new convolutional neural network algorithm for short-term forecasting. In this paper, the forecasting performance of the proposed algorithm was compared to that of four other artificial intelligence algorithms commonly used in wind speed forecasting. Numerical testing results based on data from a designated wind site in Taiwan were used to demonstrate the efficiency of above-mentioned proposed learning method. Mean absolute error (MAE) and root-mean-square error (RMSE) were adopted as accuracy evaluation indexes in this paper. Experimental results indicate that the MAE and RMSE values of the proposed algorithm are 0.800227 and 0.999978, respectively, demonstrating very high forecasting accuracy.
Frequency-Dependent Pi Model of a Three-Core Submarine Cable for Time and Frequency Domain Analysis
Authors: Ruiz Carlos , Abad Gonzalo , Zubiaga Markel , Madariaga Danel , Arza Joseba
Published: October 2018

In this paper, a Frequency-Dependent Pi Model (FDPi) of a three-core submarine cable is presented. The model is intended to be used for the representation of submarine cables in an Offshore Wind Power Plant (OWPP) scenario for both time and frequency domain analysis. The frequency-dependent variation of each conductive layer is modeled by a Foster equivalent network whose parameters are tuned by means of Vector Fitting (VF) algorithm. The complete formulation for the parameterization of the model is presented in detail, which allows an easy reproduction of the presented model. The validation of the model is performed via a comparison with a well-established reference model, the Universal Line Model (ULM) from PSCAD/EMTDC software. Two cable system case studies are presented. The first case study shows the response of the FDPi Model for a three-core submarine cable. On the other hand, the second case study depicts the response of three single-core underground cables laying in trefoil formation. This last case shows the applicability of the FDPi Model to other types of cable systems and indirectly validates the response of the aforementioned model with experimental results. Additionally, potential applications of the FDPi model are presented.
A Review of Job Role Localization in the Oil and Gas Industry
Authors: Pegram Jack , Falcone Gioia , Kolios Athanasios
Published: October 2018

Job role localization is a strategic local content solution used by countries bearing natural resource stocks to maximize the long-term benefits of exploring and producing them. Currently, there is significant variation in how countries and organizations plan and implement local content and job role localization strategies; hence, this paper aims to gather, classify, and discuss relevant literature with a view to identify best practices for future application. After a multi-dimensional discussion of key terms relevant to the topic, the drivers and theoretical underpinnings of local content are examined, followed by an assessment of job role localization literature qualifying enablers and barriers to localization. A critical discussion on the means of evaluating local content policies summarizes the findings of this critical review.
Caregiving, Employment and Social Isolation: Challenges for Rural Carers in Australia
Authors: Hussain Rafat , Wark Stuart , Ryan Peta
Published: October 2018

Australia has one of the world’s highest life expectancy rates, and there is a rapidly growing need for informal caregivers to support individuals who are ageing, have chronic illness or a lifelong disability. These informal carers themselves face numerous physical and psychological stressors in attempting to balance the provision of care with their personal life, their work commitments and family responsibilities. However, little is known about the specific challenges facing rural carers and the barriers that limit their capacity to provide ongoing support. A cross-sectional survey composed of open-ended responses and demographic/socioeconomic measures used routinely by the Australian Bureau of Statistics (ABS) and the Australian Institute of Health & Welfare (AIHW) was used with a cohort of 225 rurally-based carers within New South Wales, Australia. Demographic questions specified the respondents’ age, gender, employment, caregiving status, condition of and relationship to the care recipient, postcode, residency status, and distance and frequency travelled to provide care. Open-ended comments sections were provided to allow participants to describe any issues and problems associated with caregiving including employment, travel, residency, carer support groups and any other general information. The results show that most rural carers were middle-aged women supporting a spouse or a child. Unpredictability associated with providing care exacerbated demands on carers’ time, with many reporting significant employment consequences associated with inflexibility and limited job options in rural locations. Specific issues associated with travel requirements to assist with care were reported, as were the impacts of care provision on the respondents’ own personal health. The majority of carers were aware of the social supports available in their local rural community, but did not access them, leaving the carers vulnerable to marginalisation. Problems associated with employment were noted as resulting in financial pressures and associated personal stress and anxiety for the caregivers. While this issue is not necessarily limited to rural areas, it would appear that the lack of opportunity and flexibility evident in rural areas would exacerbate this problem for non-metropolitan residents. The participants also identified specific barriers to the provision of care in rural areas, including the significant impact of travel. Access to support services, such as carer groups, were rarely accessed due to a mix of factors including inaccessibility, poor timing and a lack of anonymity. Financially, there was considerable evidence of hardship, and there is an urgent need for a comprehensive review of government and community-based support to better meet the needs of rural carers.
Variation of Hydrothermal Conditions under Climate Change in Naqu Prefecture, Tibet Plateau, China
Authors: Gong Boya , Weng Baisha , Yan Denghua , Qin Tianling , Wang Hao , Bi Wuxia
Published: October 2018

Analysis of the suitability of hydrothermal conditions for vegetation growth would benefit the ecological barrier construction, water resources protection and climate change adaptation. The suitability of hydrothermal conditions in Naqu Prefecture was studied based on the spatial displacement of 500 mm precipitation and 2000 °C accumulated temperature contours. Results showed that the 500 mm precipitation contour had a shifting trend toward the southwest, with a 3.3-year and 7.1-year period, respectively, in the longitudinal and latitudinal direction, and the longitude changed suddenly around 1996. The 2000 °C accumulated temperature contour had a shifting trend toward the northwest, with a 1.8-year period and a 7-year sub-period in the longitudinal direction; the longitude had a catastrophe point between 1966 and 1967, while the latitude had a catastrophe point between 2005 and 2006. When located in the same vegetation zone, the annual precipitation in Naqu Prefecture was higher than the national average, while the accumulated temperature was lower than the national average, indicating that areas with suitable hydrothermal conditions suitable for vegetation growth showed a northwestward shift tendency. This research would help to support some recommendations for plants’ ecological system protection in alpine areas, and also provide guidelines for climate change adaptation.
Multiple Regulatory Networks Are Activated during Cold Stress in Medicago sativa L.
Authors: Zhou Qiang , Luo Dong , Chai Xutian , Wu Yuguo , Wang Yanrong , Nan Zhibiao , Yang Qingchuan , Liu Wenxian , Liu Zhipeng
Published: October 2018

Cultivated alfalfa (Medicago sativa L.) is one of the most important perennial legume forages in the world, and it has considerable potential as a valuable forage crop for livestock. However, the molecular mechanisms underlying alfalfa responses to cold stress are largely unknown. In this study, the transcriptome changes in alfalfa under cold stress at 4 °C for 2, 6, 24, and 48 h (three replicates for each time point) were analyzed using the high-throughput sequencing platform, BGISEQ-500, resulting in the identification of 50,809 annotated unigenes and 5283 differentially expressed genes (DEGs). Metabolic pathway enrichment analysis demonstrated that the DEGs were involved in carbohydrate metabolism, photosynthesis, plant hormone signal transduction, and the biosynthesis of amino acids. Moreover, the physiological changes of glutathione and proline content, catalase, and peroxidase activity were in accordance with dynamic transcript profiles of the relevant genes. Additionally, some transcription factors might play important roles in the alfalfa response to cold stress, as determined by the expression pattern of the related genes during 48 h of cold stress treatment. These findings provide valuable information for identifying and characterizing important components in the cold signaling network in alfalfa and enhancing the understanding of the molecular mechanisms underlying alfalfa responses to cold stress.
An Ultradian Feeding Schedule in Rats Affects Metabolic Gene Expression in Liver, Brown Adipose Tissue and Skeletal Muscle with Only Mild Effects on Circadian Clocks
Authors: De Goede Paul , Sen Satish , Su Yan , Foppen Ewout , Poirel Vincent-Joseph , Challet Etienne , Kalsbeek Andries
Published: October 2018

Restricted feeding is well known to affect expression profiles of both clock and metabolic genes. However, it is unknown whether these changes in metabolic gene expression result from changes in the molecular clock or in feeding behavior. Here we eliminated the daily rhythm in feeding behavior by providing 6 meals evenly distributed over the light/dark-cycle. Animals on this 6-meals-a-day feeding schedule retained the normal day/night difference in physiological parameters including body temperature and locomotor activity. The daily rhythm in respiratory exchange ratio (RER), however, was significantly phase-shifted through increased utilization of carbohydrates during the light phase and increased lipid oxidation during the dark phase. This 6-meals-a-day feeding schedule did not have a major impact on the clock gene expression rhythms in the master clock, but did have mild effects on peripheral clocks. In contrast, genes involved in glucose and lipid metabolism showed differential expression. In conclusion, eliminating the daily rhythm in feeding behavior in rats does not affect the master clock and only mildly affects peripheral clocks, but disturbs metabolic rhythms in liver, skeletal muscle and brown adipose tissue in a tissue-dependent manner. Thereby, a clear daily rhythm in feeding behavior strongly regulates timing of peripheral metabolism, separately from circadian clocks.
Tissue-Specific Profiling of Oxidative Stress-Associated Transcriptome in a Healthy Mouse Model
Authors: Kim Jung Min , Kim Hyeong Geug , Son Chang Gue
Published: October 2018

Oxidative stress is a common phenomenon and is linked to a wide range of diseases and pathological processes including aging. Tissue-specific variation in redox signaling and cellular responses to oxidative stress may be associated with vulnerability especially to age-related and chronic diseases. In order to provide a basis for tissue-specific difference, we examined the tissue-specific transcriptional features of 101 oxidative stress-associated genes in 10 different tissues and organs of healthy mice under physiological conditions. Microarray analysis results, which were consistent with quantitative polymerase chain reaction (qPCR) results, showed that catalase, Gpx3, and Gpx4 were most highly regulated in the liver, kidney, and testes. We also found the tissue-specific gene expression of SOD1 (liver and kidney), SOD2 (heart and muscle), and SOD3 (lung and kidney). The current results will serve as a reference for animal models and help advance our understanding of tissue-specific variability in oxidative stress-associated pathogenesis.
5-Azacytidine: A Promoter of Epigenetic Changes in the Quest to Improve Plant Somatic Embryogenesis
Authors: Osorio-Montalvo Pedro , Sáenz-Carbonell Luis , De-la-Peña Clelia
Published: October 2018

Somatic embryogenesis (SE) is a widely studied process due to its biotechnological potential to generate large quantities of plants in short time frames and from different sources of explants. The success of SE depends on many factors, such as the nature of the explant, the microenvironment generated by in vitro culture conditions, and the regulation of gene expression, among others. Epigenetics has recently been identified as an important factor influencing SE outcome. DNA methylation is one of the most studied epigenetic mechanisms due to its essential role in gene expression, and its participation in SE is crucial. DNA methylation levels can be modified through the use of drugs such as 5-Azacytidine (5-AzaC), an inhibitor of DNA methylation, which has been used during SE protocols. The balance between hypomethylation and hypermethylation seems to be the key to SE success. Here, we discuss the most prominent recent research on the role of 5-AzaC in the regulation of DNA methylation, highlighting its importance during the SE process. Also, the molecular implications that this inhibitor might have for the increase or decrease in the embryogenic potential of various explants are reviewed.
Preamplification with dUTP and Cod UNG Enables Elimination of Contaminating Amplicons
Authors: Andersson Daniel , Svec David , Pedersen Cathrine , Henriksen Jørn Remi , Ståhlberg Anders
Published: October 2018

Analyzing rare DNA and RNA molecules in limited sample sizes, such as liquid biopsies and single cells, often requires preamplification, which makes downstream analyses particularly sensitive to polymerase chain reaction (PCR) generated contamination. Herein, we assessed the feasibility of performing Cod uracil-DNA N-glycosylase (Cod UNG) treatment in combination with targeted preamplification, using deoxyuridine triphosphate (dUTP) to eliminate carry-over DNA. Cod UNG can be completely and irreversibly heat inactivated, a prerequisite in preamplification methods, where any loss of amplicons is detrimental to subsequent quantification. Using 96 target assays and quantitative real-time PCR, we show that replacement of deoxythymidine triphosphate (dTTP) with dUTP in the preamplification reaction mix results in comparable dynamic range, reproducibility, and sensitivity. Moreover, Cod UNG essentially removes all uracil-containing template of most assays, regardless of initial concentration, without affecting downstream analyses. Finally, we demonstrate that the use of Cod UNG and dUTP in targeted preamplification can easily be included in the workflow for single-cell gene expression profiling. In summary, Cod UNG treatment in combination with targeted preamplification using dUTP provides a simple and efficient solution to eliminate carry-over contamination and the generation of false positives and inaccurate quantification.
Vanin-1 in Renal Pelvic Urine Reflects Kidney Injury in a Rat Model of Hydronephrosis
Authors: Hosohata Keiko , Jin Denan , Takai Shinji , Iwanaga Kazunori
Published: October 2018

Urinary tract obstruction and the subsequent development of hydronephrosis can cause kidney injuries, which results in chronic kidney disease. Although it is important to detect kidney injuries at an early stage, new biomarkers of hydronephrosis have not been identified. In this study, we examined whether vanin-1 could be a potential biomarker for hydronephrosis. Male Sprague-Dawley rats were subjected to unilateral ureteral obstruction (UUO). On day 7 after UUO, when the histopathological renal tubular injuries became obvious, the vanin-1 level in the renal pelvic urine was significantly higher than that in voided urine from sham-operated rats. Furthermore, vanin-1 remained at the same level until day 14. There was no significant difference in the serum vanin-1 level between sham-operated rats and rats with UUO. In the kidney tissue, the mRNA and protein expressions of vanin-1 significantly decreased, whereas there was increased expression of transforming growth factor (TGF)-β1 and Snail-1, which plays a pivotal role in the pathogenesis of renal fibrosis via epithelial-to-mesenchymal transition (EMT). These results suggest that vanin-1 in the renal pelvic urine is released from the renal tubular cells of UUO rats and reflects renal tubular injuries at an early stage. Urinary vanin-1 may serve as a candidate biomarker of renal tubular injury due to hydronephrosis.