Order Transfer Research Articles

Impact analysis of MPL and PEM thickness on temperature distribution within PEFC operating at relatively higher temperature

In Japan, it is recommended to operate Polymer Electrolyte Fuel Cell (PEFC) at temperature around 90 °C for stationary applications during the period from 2020 to 2025. However, the present PEFC is using Nafion polymer electrolyte membrane (PEM) and operated within the temperature range from 60 °C to 80 °C. It is important to understand the temperature distribution in a cell of PEFC for improving the performance and to realize the long life span. This study focuses on use of micro porous layer (MPL), which can promote the moisture transfer in order to control the temperature distribution. The aim of this study is to analyze the impact of MPL on temperature distribution at reaction surface in single cell of PEFC during the variations of flow rates and relative humidity of supply gases. In the operation, relatively higher temperature 90 °C is maintained and analyzed through the heat transfer model. This study also investigates the impact of PEM thickness on the temperature distribution comparing the conditions with and without MPL. As a result, it is proposed that the combination of thinner PEM and MPL can be effective to manage temperature distribution uniformly, and obtain better PEFC performance at relatively higher temperature operation.

The analytical and numerical solutions of two dimensional heat transfer equation in a multilayered composite cylinder

Heat transfer is one of the most observed phenomena in the fields of aerospace, industry, nuclear, power generation, automotive, etc. Currently, materials for heat transfer are made of composites of various types so that they have different properties from their constituent materials. To understand the phenomenon of heat transfer in order to save costs and risks that can arise, it can be done by simulation. In this paper, we describe analytical and numerical solutions for two dimensional (2D) heat transfer equation in a multilayered composite cylinder. In particular, we use eigen function method to find the analytical solution and finite difference method to generate the numerical solution. The simulation of heat transfer for different time frame carried out using Python 3.7 with Numpy library.

Aramco: The Story of the World’s Most Valuable Oil Concession and Its Landmark Arbitration

The Aramco story is a fascinating and colourful history of the world’s most valuable oil concession, the challenges overcome by its original American owners and the orderly transfer of control of the world’s largest oil company to the Kingdom of Saudi Arabia. It involved the largest American overseas investment, a cornerstone of U.S. foreign policy, the stabilization of global energy markets and the Middle East region, along with the transformation of a medieval society into a modern state. Unlike some of the other states in the region, Saudi Arabia never intended to nationalize or expropriate Aramco. Instead, it worked closely with its American investors and the American government to maximize production for the benefit of all the parties involved. The parties did this within a long tradition of “friendship and good will.” Despite their best efforts, they did come to blows in a landmark arbitration, the Saudi Arabia v.Aramco Arbitration, which is one of the most historically important investor state arbitrations of the last century.This article describes that case with insightful detail, along with how the parties maintained their “friendly relationship” long after the end of the arbitration.

Cathode catalyst layer with nanofiber microstructure for direct methanol fuel cells

Due to eco-friendly production and running processes, direct methanol fuel cell has been considered as a clean and green energy generation technology. However, the dissatisfactory discharge performance of fuel cell, mainly caused by low-efficient catalyst layers, has limited its commercialization. To improve the electrochemical active surface area, herein, the novel cathode catalyst layer with nanofiber microstructure has been prepared by adding water additive into the catalyst slurry, during the heat-spray process, for enhancing electrochemical performance of direct methanol fuel cells. In the catalyst slurry, owing to its high molecular polarity, the water phase collects polar parts of Nafion molecules, i.e. sulfonic acid group, together to form the polar region. Simultaneously, the nonpolar fluorocarbon chain spreads into an isopropanol phase to form the low-polar region. The distinction between polar and non-polar regions provides a structural basis for orderly mass transfer inside the catalyst layer. Finally, the novel catalyst layer exhibits a 34.7% increase in electrochemical active surface area and signally enhanced mass transport properties, leading to a 41.5% improvement in the power density of the fuel cell. This design to concurrently enhance electroactive surface area and build order mass transfer provides a new strategy for developing high-performance catalyst layers.

Observation of Low-γ Quadrupolar Nuclei by Surface-Enhanced NMR Spectroscopy.

We introduce a novel NMR approach that extends the capabilities of indirect dynamic nuclear polarization (DNP) under magic-angle spinning to probe the local environment of half-integer spin quadrupolar nuclei. Compared to cross-polarization, this novel method based on the refocused INEPT scheme with adiabatic dipolar recoupling is easier to optimize and does not distort the quadrupolar line shapes. Furthermore, the use of this technique, instead of the PRESTO (Phase-shifted Recoupling Effects a Smooth Transfer of Order) scheme or direct DNP, greatly improves the sensitivity of DNP-NMR for the detection of quadrupolar isotopes with small dipolar couplings to protons, including notably those located in the subsurface of inorganic materials or with low gyromagnetic ratio (γ). This technique has been applied to identify the atomic-level structure of Brønsted acid sites of hydrated titania-supported MoO3, MoO3/TiO2, a widely used heterogeneous catalyst. The spectra of protonated and unprotonated 17O sites, acquired in natural abundance, indicate the presence of various oxomolybdate species as well as HOMo2 and HOMo3 Brønsted acid sites. The enhanced sensitivity of this new method has also enabled the acquisition of the first DNP-enhanced spectra of 95Mo and 47,49Ti low-γ quadrupolar isotopes. This possibility has been demonstrated by detecting the signals of these nuclei near the surface of MoO3/TiO2. This technique has allowed the observation of 49Ti surface sites, which are absent from the bulk region of TiO2. Furthermore, both 95Mo and 47,49Ti DNP spectra have shown an increased structural disorder of TiO2 and MoO3 phases near the surface of the particles and notably the preferential location of the amorphous TiO2 phase at the surface of the particles. The proposed polarization transfer is also employed to acquire the first DNP-enhanced spectrum of 67Zn, another low-γ quadrupolar isotope. This possibility is demonstrated for Al-doped ZnO nanoparticles used in optoelectronic devices. The obtained 17O, 27Al, and 67Zn DNP-NMR data prove that the surface region of these nanoparticles contains ZnO phase as well as secondary phases, such as α-Al2O3 and partially inverse ZnAl2O4 spinel.

The binary evolution of SAX J1808.4−3658: implications of an evolved donor star

ABSTRACT Observations of the accretion powered millisecond pulsar SAX J1808.4−3658 have revealed an interesting binary evolution, with the orbit of the system expanding at an accelerated rate. We use the recent finding that the accreted fuel in SAX J1808.4−3658 is hydrogen depleted to greatly refine models of the progenitor and prior evolution of the binary system. We constrain the initial mass of the companion star to 1.0–1.2 M⊙, more massive than previous evolutionary studies of this system have assumed. We also infer the system must have undergone strongly non-conservative mass transfer in order to explain the observed orbital period changes. We include mass loss due to the pulsar radiation pressure on the donor star, inducing an evaporative wind which is ejected at the inner Lagrangian point of the binary system. The resulting additional loss of angular momentum resolves the discrepancy between conservative mass transfer models and the observed orbital period derivative of this system. We also include a treatment of donor irradiation due to the accretion luminosity, and find this has a non-negligible effect on the evolution of the system.

Identification scheme for fractional Hammerstein models with the delayed Haar wavelet

The parameter identification of a nonlinear Hammerstein-type process is likely to be complex and challenging due to the existence of significant nonlinearity at the input side. In this paper, a new parameter identification strategy for a block-oriented Hammerstein process is proposed using the Haar wavelet operational matrix (HWOM). To determine all the parameters in the Hammerstein model, a special input excitation is utilized to separate the identification problem of the linear subsystem from the complete nonlinear process. During the first test period, a simple step response data is utilized to estimate the linear subsystem dynamics. Then, the overall system response to sinusoidal input is used to estimate nonlinearity in the process. A single-pole fractional order transfer function with time delay is used to model the linear subsystem. In order to reduce the mathematical complexity resulting from the fractional derivatives of signals, a HWOM based algebraic approach is developed. The proposed method is proven to be simple and robust in the presence of measurement noises. The numerical study illustrates the efficiency of the proposed modeling technique through four different nonlinear processes and results are compared with existing methods.

Comparison of Particle Swarm Optimization and Ziegler Nichols Techniques

Two tuning techniques namely: Particle Swarm Optimization (PSO) and Ziegler Nichols (ZN) technique are compared. PSO is an optimization technique based on the movement and intelligence of swarms. PSO applies the concept of social interaction to problem solving. It is a computational method that optimizes a problem by iteratively trying to improve a candidate solution about a given measure of quality. Ziegler Nichols tuning method is a heuristic method of tuning a PID controller. The ZN close loop tuning is performed by setting the I (integral) and D (derivative) gains to zero and increasing proportional gain to obtain sustained oscillations. The DC Motor is represented by second order transfer function is used as a plant, which is controlled using PID controller. The PID controller parameters are chosen by tuning the controller using PSO algorithm and ZN method. The response of the system to unit step input is plotted and performance measures are evaluated for comparing PSO algorithm and ZN technique. Here we have compared the two tuning methods based upon the settling time (Ts), peak overshoot (Mp) and the two performance indices namely Integral square error (ISE) and Integral Absolute error (IAE).

Economic Growth Effects on B&R Sci-Tech Cooperation

The “Belt and Road” is a path of innovation, and sci-tech cooperation is the forerunner and support of B&R construction. However, what are the main patterns of cooperation? What are the mechanism and effect acting on the economic growth of countries along B&R? How to improve the quality and effect of cooperation? All these questions are worth to discuss in order to build B&R sci-tech cooperation network and B&R Community of Innovation. Although existing researches have made extensive analysis and research, there are still two shortcomings. First, most of them focus on the patterns of B&R sci-tech cooperation, but pay little attention to the mechanism and effect. Second, there is little empirical evidence on sci-tech cooperation promoting economic growth in countries along B&R.This paper attempts to make a comprehensive analysis on the above questions. And it finds that the sci-tech cooperation between countries along B&R and China is at its initial stage, mostly carried out by China’s neighbor such as Southeast Asian and South Asian countries, and is narrowed in cooperation scope. All kinds of cooperation can be classified as R&D cooperation and technology transfer, which promote the economic growth of countries along B&R by affecting R&D ability and knowledge stock respectively, and have different effects on countries with different technological endowment. The economic growth effects of R&D cooperation and technology transfer are mutually reinforcing. Therefore, carrying out the two types of cooperation simultaneously can promote the innovation and growth effects greatly. If countries along B&R are divided into innovation laggards and innovation pursuers, the effect of R&D cooperation is obviously different between the two groups, which is related to the technical level and difficulty of cooperation. It is also related to the direct productivity effect of technology transfer. Therefore, we can get the inspiration that B&R sci-tech cooperation should adopt different strategies in different countries according to the actual conditions, stick to the parallel development of R&D cooperation and technology transfer, and emphasize the technological endowment and quality of R&D cooperation.This paper adds to the existing literature in the following two ways: First, in terms of cooperation mechanism, it divides the existing patterns of B&R sci-tech cooperation into two categories: R&D cooperation in order to enhance the R&D capabilities of related countries, and technology transfer in order to increase their knowledge stock. Second, in terms of R&D conditions, this paper divides the related countries into two groups: backward countries and catch-up countries, investigates and compares B&R sci-tech cooperation’s effects on the economic growth in different group countries, and gives suggestion on how to improve sci-tech cooperation accordingly.

Utility of transport risk index of physiological stability score for predicting likely outcome of extramural neonates transferred to NICU

Background: To accomplish ‘Mission Twenty - Twenty’ and to achieve ‘Sustainable Development Goal 3’, now we need to focus our attention more towards neonates being transported to higher centre in this very fragile period. We planned this study to assess demographic, transport and clinical characteristics of referred neonates and to determine whether TRIPS score serves as predictor of early neonatal mortality i.e. mortality within the first seven days after admission in these babies.Methods: This cross sectional descriptive study with analytic components was carried out in a tertiary care teaching hospital. All neonates ≥1 kg, born outside of this hospital, and referred here during study period for further management were included. All the data pertaining to clinical, demographic and transport characteristics were recorded. TRIPS score was applied at admission and was related with the final outcome within first seven days of admission; expired or survived. The association between the outcome and TRIPS score was tested using chi square test or fisher’s exact test. ROC curve analysis was done to find out optimum TRIPS score to predict mortality.Results: Neonatal mortality within first 7 days after admission is related to the TRIPS rating. The score of the survivors and neonatal deaths show a significant difference which is also even reflected by its individual components (p< 0.001). For a score of >18.5, a sensitivity of 89.47% and a specificity of 91.47%; area under the curve of 0.954 was determined.Conclusions: TRIPS score is a valid predictor of early neonatal mortality. The components of TRIPS score also correlate with early neonatal death. It is important to establish measures to improve physiological stability of the newborn before, during and after the transfer in order to reduce neonatal mortality.

Active boundary and interior absorbers for one-dimensional wave propagation: Application to transmission-line metamaterials

We address the problem of generating active absorbers for wave propagation in a class of one-dimensional continuous media. In particular, we consider the emerging application of metamaterials, which are engineered structures supporting unconventional wave propagation phenomena. We design two kinds of absorbers. The first absorber achieves a complete elimination of wave reflections from the metamaterial boundaries independently of the working frequency regime. The associated controller is implemented in a feedback loop and is given in general terms of the metamaterial effective constitutive parameters. The second absorber blocks wave propagation beyond a prescribed location at the metamaterial interior with minimized back-scattering, thus generating a sink without any physical boundary present. It is implemented in a feed-forward loop via a unique near unidirectional control wave method, using two concentrated actuators. Both the interior and boundary absorbers are based on an exact fractional order transfer function model that we derive for the metamaterial. The model explicitly exhibits essential wave characteristics, including delays, dispersion, impedance, boundary reflections etc. The resulting controllers are of fractional order as well and are realized via a dedicated approximation technique. We verify the results by numerical simulations of a representative mechanical metamaterial.

A Systematic Literature Review Method On AES Algorithm for Data Sharing Encryption On Cloud Computing

Cloud computing is one revolution in information technology (IT) that can share resources, services and data through a network among users. Because users have same rights on the network to transfer data, data are vulnerable to be attacked by unauthorized person. Lately, data security in a system only concentrates on data storage on cloud by utilizing internet security, but a little concentration is found during data transfer. By considering security as a serious problem, an encryption-based proposed system is presented to secure during data transfer. Authors propose an approach to boost system security during data transfer in order to prevent data theft by unauthorized person. To prevent an attack by unauthorized person, Advanced Encryption Standard (AES) will be proposed to secure data transfer and storage in cloud computing. For better future, authors will propose Systematic Literature Review (SLR) to generate suggestions and opportunities in AES cloud computing.

Maxillofacial Trauma Management During COVID-19: Multidisciplinary Recommendations.

Maxillofacial Trauma Management During COVID-19: Multidisciplinary Recommendations.

DFT Study on Adsorption of Acetone and Toluene on Silicene

In this work, we investigated the adsorption mechanism of acetone and toluene on the surface of silicene by the quantum simulation method. The images of the potential energy surfaces for different positions of the adsorbate on the silicene surface were explored by Computational DFT-based Nanoscope tool for determination of the most stable configurations and diffusion possibilities. The charge transfer in order of 0.2 – 0.3 electrons and the tunneling gap opening of 18 – 23 meV due to acetone and toluene, respectively, suggest that silicene is considerably sensitive with these VOCs and can be used as the material in the fabrication of reusable VOC sensors.

The Inverted Free Functioning Gracilis Muscle Transfer For Restoration of Elbow Flexion Following Delayed Presentation or Failed Primary Nerve Reconstruction of Upper Trunk Injuries.

Free functional gracilis transfer is a well-established technique for restoring active elbow flexion in brachial plexus injuries following delayed presentation or failed nerve reconstruction procedures. In cases of delayed presentation or failed nerve reconstruction following upper trunk injuries, the lower trunk intraplexal median and ulnar nerves are spared, thereby making them available to reinnervate the transferred gracilis. Therefore, we have inverted the conventional free functional gracilis orientation so as to orient the flap's recipient nerve in closer proximity to donor median or ulnar nerve fascicles to enable a short, tension-free coaptation in the middle to distal arm. Herein is our descriptive surgical technique for performing an inverted free functional gracilis muscle transfer in order to restore elbow flexion in the setting of an upper trunk injury.

In Memoriam: Professor Ephraim Maurice Sparrow

In Memoriam: Professor Ephraim Maurice Sparrow

Computational modeling and neutron imaging to understand interface shape and solute segregation during the vertical gradient freeze growth of BaBrCl:Eu

Abstract We apply continuum models to analyze phase change, heat transfer, fluid flow, solute transport, and segregation in order to understand prior neutron imaging observations of the vertical gradient freeze growth of Eu-doped BaBrCl. The models provide a rigorous framework in which to understand the mechanisms that are responsible for the complicated evolution of interface shape and dopant distribution in the growth experiment. We explain how a transition in the solid/liquid interface shape from concave to convex is driven by changes in radial heat transfer caused by furnace design. We also provide a mechanistic explanation of how dynamic growth conditions and changes of the flow structure in the melt result in complicated segregation patterns in this system. A growth pause caused by controller lock-up is shown to result in a band of solute depletion in accordance with classical theory. However, changing flow patterns during growth result in a non-monotonic axial distribution of solute that cannot be explained by simple application of classical segregation models. We assert that the approach presented here, namely the use of rigorous models in conjunction advanced diagnostics, such as neutron imaging, provides an exciting path forward for process optimization and control, accelerating the incremental advances that have, in the past, typically relied on empiricism, experience, and intuition.

The Molecular Mechanism of Polymer Formation of Farnesylated Human Guanylate-binding Protein 1

The human guanylate-binding protein 1 (hGBP1) belongs to the dynamin superfamily proteins and represents a key player in the innate immune response. Farnesylation at the C-terminus is required for hGBP1’s activity against microbial pathogens, as well as for its antiproliferative and antitumor activity. The farnesylated hGBP1 (hGBP1fn) retains many characteristics of the extensively studied nonfarnesylated protein and gains additional abilities like binding to lipid membranes and formation of hGBP1fn polymers. These polymers are believed to serve as a protein depot, making the enzyme immediately available to fight the invasion of intracellular pathogens. Here we study the molecular mechanism of hGBP1 polymer formation as it is a crucial state of this enzyme, allowing for a rapid response demanded by the biological function. We employ Förster resonance energy transfer in order to trace intra and intermolecular distance changes of protein domains. Light scattering techniques yield deep insights into the changes in size and shape. The GTP hydrolysis driven cycling between a closed, farnesyl moiety hidden state and an opened, farnesyl moiety exposed state represents the first phase, preparing the molecule for polymerization. Within the second phase of polymer growth, opened hGBP1 molecules can be incorporated in the growing polymer where the opened structure is stabilized, similar to a surfactant molecule in a micelle, pointing the farnesyl moieties into the hydrophobic center and positioning the head groups at the periphery of the polymer. We contribute the molecular mechanism of polymer formation, paving the ground for a detailed understanding of hGBP1 function.

Order fulfilment problem with time windows and synchronisation arising in the online retailing

In this paper, we study the order fulfilment problem with time windows and synchronisation, which arises in the online retailing environment. Given customer orders released in the time window of decision, the online retailer needs to decide which fulfilment centre should fulfil customer orders, how to rigidly coordinate and synchronise operations of different types of vehicles, and how to deliver orders while meeting customers' service time windows, to minimise expenses of order fulfilment. We first introduce a mixed-integer linear programming model, which faces a significant computation burden. To that end, we develop a decomposition-based approach. We conduct extensive experiments to verify the effectiveness of our approach by comparing it with a commercial solver, and a greedy heuristic. We also present managerial insights regarding how our approach could reduce the order transfer operations at the distribution centres and thereby optimise the e-order fulfilment expenses.

Water-dispersed semiconductor nanoplatelets with high fluorescence brightness, chemical and colloidal stability.

Quasi-two dimensional semiconductor nanoplatelets (NPLs) exhibit high spectral brightness and large absorption cross sections, making them promising for various applications including bioimaging. However, the synthesis of NPLs takes place in organic solvents, therefore they require phase transfer in order to use them in aqueous environments. The phase transfer of NPLs has so far been challenging with few examples in literature. This is likely due to the facile agglomeration of materials with plate-like geometries during the coating procedure. Here we demonstrate how to overcome agglomeration and transfer NPLs, individually coated with amphiphilic polymer chains, to aqueous phase. Upon one and two-photon excitation the water transferred NPLs exhibit more than two fold higher fluorescent brightness relative to commercially available quantum dots. Additionally, the polymer coating increase the stability of nanoparticles in physiological conditions (pH 4.5-7.4, [NaCl] 5.8-11.7 g L-1, and in human serum). Our experiments with NPL labeled RAW264.7 cells demonstrate the capabilities of NPLs as next generation ultra-bright fluorescent labels for bioimaging.