Methane (CH4) is the major component of currently abundant natural gas and a prominent green-house gas. Steam reforming of methane (SRM) is an important technology for the conversion of CH4 into H2 ...and syngas. To improve the catalytic activity and coking resistance of SRM catalysts, great efforts (including the addition of promoters, development of advanced supports, and structural modification, etc.) have been made with considerable progress in the past decade. Meanwhile, a series of novel processes have been explored for more efficient and energy-saving SRM. In this scenario, a comprehensive review on the recent advances in SRM is necessary to provide a constructive insight into the development of SRM technology, however, is still lacking. Herein, the improvements in catalyst construction for conventional SRM and the newly developed SRM processes in the past decade are presented and analyzed. First, the critical issues of SRM catalysts are briefly introduced. Then, the recent research advances of the most popular Ni based catalysts and the catalysts based on the other non-noble metals (Co, Cu, Mo etc.) and the efficient but costly noble metals (Au, Pt, Pd, Rh, Ru etc.) are discussed. Furthermore, the development of the representative modified SRM processes, including thermo-photo hybrid SRM, sorbent enhanced SRM, oxidative SRM, chemical looping SRM, plasma and electrical-field enhanced SRM, is demonstrated, and their advantages and limits are compared. Finally, a critical perspective is provided to enlighten future work on this significant area.
•Steam reforming of methane (SRM) makes valuable use of abundant natural gas efficiently.•SRM is attractive for global warming mitigation and green energy (H2) production.•Recent efforts in catalyst design for efficient and stable SRM are addressed.•Advanced SRM technologies with hybrid processes have shown great promise.•Future efforts in novel SRM system for value added products is intriguing.
Due to its inherent characteristics, the Switched Reluctance Motor (SRM) is an up-and-coming contender for further investigation and analysis across diverse industrial domains. One of these domains ...is the field of electric vehicles(EVs), but this is no exclusive category. The mechanical design of the motor is notable for the inherent simplicity it possesses as well as the cost-effectiveness it offers. This article presents a comprehensive analysis of SRMs, including detailed descriptions, an in-depth review of their advantages and disadvantages, an investigation of their applications, and torque-speed profile and power speed profile graphical representations. The discussion incorporates the most recent findings from research on the methodologies and control strategies used.
The principal idea of this study is to examine the buoyancy effect on two-dimensional flow of Casson fluid and mixed convection over a nonlinear stretching sheet. The governing equations of the ...present study along with suitable boundary conditions are transformed into non dimensional differential equations along with appropriate boundary conditions by using similarity transformations. Spectral relaxation method is applied to study the considered problem as numerically. Moreover in case of linear stretching Exact solution is also performed. To improve the effectiveness and accuracy of the proposed method spectral over relaxation method is used. The effects of various emerging parameters are studied to analyze temperature, local Nusselt number, friction factor and velocity by means of graphs and tables. Numerical outcomes are validated by comparing the outcomes obtained and existing literature. Mainly, noticed that, enhancement in the velocity and decrement in temperature for the increasing augments of the buoyancy parameter.
A116Cd–106Cd double‐spike method in combination with thermal ionization mass spectrometry (TIMS) was applied to obtain cadmium (Cd) mass fractions and stable isotope compositions in seven biogenic ...certified reference materials (pine needles, tomato leaves, spinach leaves, lichen, mussel tissue, oyster tissue, and pig kidney). This sample set was supplemented by the analysis of two manganese nodules and one soil reference material for which the Cd isotopic data has already been reported. The intermediate measurement precision of the whole protocol as determined for the NIST SRM 3108 Cd standard solution yields an excellent value of δ114/110Cd of −0.005 ± 0.029‰ (2SD, n = 47). The Cd isotopic compositions of the biogenic materials, reported as δ114/110Cd relative to NIST SRM 3108, range from −0.52 to +0.50‰. Plants show δ114/110Cd mean values ranging from −0.09 to +0.45‰ whereas the δ114/110Cd value of −0.17‰ was detected in the lichen and the values of −0.51, −0.52, and +0.47‰ were gathered for the oyster, mussel, and pig kidney tissues, respectively. The observed large variation of the δ114/110Cd values in the biogenic reference materials indicates a potential to use the natural mass-dependent Cd isotope fractionation in environmental, biogeochemical, and physiological studies.
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•Double spike TIMS technique used for Cd isotopic composition analysis.•High-precision Cd isotopic data for biogenic reference materials.•Mean δ114/110Cd values ranged from −0.52 to +0.47‰.
The presented paper is to investigate the characteristics of the switched reluctance motor (SRM) under different types of controllers. For this study, two different control strategies; namely; ...voltage and current control strategies are considered. The theoretical background of under consideration controllers is reported. The motor structure, model equations, operation principles as well as the power converter topology and operation are carried out in this research. Motor magnetic characteristics such as inductance profile, phase flux linkages, and static torque profile are studied and simulated. Simulation results of motor performance under each controller are presented. Some recommended conclusions about the SRM suitable controller type selection are introduced.
Targeted mass spectrometry‐based proteomics approaches enable the simultaneous and reproducible quantification of multiple protein analytes across numerous conditions in biology and clinical studies. ...These approaches involve e.g. selected reaction monitoring (SRM) typically conducted on a triple quadrupole mass spectrometer, its high‐resolution variant named pseudo‐SRM (p‐SRM), carried out in a quadrupole coupled with an TOF analyzer (qTOF), and “sequential window acquisition of all theoretical spectra” (SWATH). Here we compared these methods in terms of signal‐to‐noise ratio (S/N), coefficient of variance (CV), fold change (FC), limit of detection and quantitation (LOD, LOQ). We have shown the highest S/N for p‐SRM mode, followed by SRM and SWATH, demonstrating a trade‐off between sensitivity and level of multiplexing for SRM, p‐SRM, and SWATH. SRM was more sensitive than p‐SRM based on determining their LOD and LOQ. Although SWATH has the worst S/N, it enables peptide multiplexing with post‐acquisition definition of the targets, leading to better proteome coverage. FC between breast tumors of different clinical‐pathological characteristics were highly correlated (R2>0.97) across three methods and consistent with the previous study on 96 tumor tissues. Our technical note presented here, therefore, confirmed that outputs of all the three methods were biologically relevant and highly applicable to cancer research.
This paper investigates application of an unconstrained model predictive controller (MPC) known as a finite horizon linear quadratic regulator (LQR) for current control of a switched reluctance motor ...(SRM). The proposed LQR can cope with the measurement noise as well as uncertainties within the machine inductance profile. This paper utilizes MPC to generate the optimal duty cycles for drive of SRMs using pulse-width modulation (PWM) in oppose to delta-modulation. In this paper, first a practical MPC scheme for embedded implementation of the system is introduced. Afterward, Kalman filtering is used for state estimation while an adaptive controller is used to dynamically tune and update both MPC and Kalman models. Hence, the overall control structure is considered as a stochastic MPC with adaptive model calibration. Finally, simulation and experimental results are provided to demonstrate the effectiveness of the proposed method.
In this paper, rotor of switched reluctance motor (SRM) is employed by mounting copper windings on the rotor poles as well as the stator poles. Rotor and stator windings are excited from DC supply in ...order to increase the developed electro-magnetic torque; thus enhancing the output power of the drive and keeping the system compactness. Furthermore, the proposed SRM offers higher reliability than conventional one, if excitation of rotor windings is lost, the drive will turn into a conventional SRM, the drive will continue running as a conventional SRM. Finite element method magnetics (FEMM) software is applied to obtain the magnetic characteristics of the proposed SRM. A control strategy for excitation of rotor and stator windings is presented. MATLAB/Simulink modeling of the proposed SRM is given and validated by practical experiment. Experimental Results on a prototype show that the proposed SRM is capable of achieving an increased torque compared with conventional SRM drive.
This paper presents a single-phase switched reluctance motor (SRM) with skewed stator and rotor so that the acoustic noise and vibration have been significantly reduced. The motor has the same skew ...angle for both stator and rotor laminations. The main source of acoustic noise and vibration is the rapid change of radial magnetic force along the air gap between the stator and rotor poles. Since the radial force (RF) is most intensified on the stator yoke near the salient poles, the abrupt change of the RF can be mitigated by skewing the stator and/or rotor laminations. Therefore, the RF can be more distributed throughout the stator core, and in turn, the peak value of the RF is reduced. In this paper, the distribution of the RF with respect to the skew angles is analyzed through the finite-element method simulation to design a single-phase SRM with the significantly reduced vibration and noise. Based on the simulation results, prototype motors with three different skew angles (0°, 30°, and 64°) have been constructed and tested, validating that the proposed design is effective in mitigating acoustic noise and vibration.
SCF (Skp1-Cullin-F-box) ubiquitin ligases comprise several dozen modular enzymes that have diverse roles in biological regulation. SCF enzymes share a common catalytic core containing Cul1⋅Rbx1, ...which is directed toward different substrates by a variable substrate receptor (SR) module comprising 1 of 69 F-box proteins bound to Skp1. Despite the broad cellular impact of SCF enzymes, important questions remain about the architecture and regulation of the SCF repertoire, including whether SRs compete for Cul1 and, if so, how this competition is managed. Here, we devise methods that preserve the in vivo assemblages of SCF complexes and apply quantitative mass spectrometry to perform a census of these complexes (the “SCFome”) in various states. We show that Nedd8 conjugation and the SR exchange factor Cand1 have a profound effect on shaping the SCFome. Together, these factors enable rapid remodeling of SCF complexes to promote biased assembly of SR modules bound to substrate.
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•Cand1-driven equilibration of SCF enzymes in lysate is quelled by molecular sponge•Assembly of F-box proteins into SCF complexes ranges from 0%–70%; median of ∼19%•Cellular SCF repertoire is tightly regulated by Nedd8 and Cand1/2•Cells preferentially accumulate a specific SCF ligase when its substrate is present
A cell’s repertoire of SCF ubiquitin ligases, which target proteins for degradation, is directly shaped by the substrates that are present.
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