A physics-based equivalent circuit model (ECM) is derived by applying finite volume method to a pseudo-two-dimensional (P2D) model of lithium-ion (Li-ion) batteries. Only standard passive components ...are used to construct the equivalent circuit, which reflects the fact that a Li-ion battery is an energy storage device. Voltages across and currents through the circuit elements in the ECM are identified with the respective internal electrochemical processes in the battery, thus allowing the parametric values of circuit elements to be expressed as functions of the Li-ion concentrations and temperature. Variations in the parametric values across the thickness of the battery leads to a distributed-parameter ECM amenable for wide range of applications. Furthermore, in contrast to existing reduced-order models of Li-ion battery which are described by differential algebraic equations, the ECM is governed by ordinary different equations wherein all the circuit components are expressed as explicit functions of the state and input variables. Hence, the developed model allows solution to be found directly using matrix algebra, resulting in rapid simulation study suitable for the development of computationally-efficient real-time battery control algorithm. Results of simulation based on the developed distributed-parameter ECM show close agreement with those obtained from a partial differential equation based P2D model under wide range of applied current rate, but at a much reduced computational burden.
Although numerous porous adsorbents have been investigated for NH3 capture applications, these materials often exhibit insufficient NH3 uptake, low NH3 affinity at the ppm level, and poor chemical ...stability against wet NH3 conditions. The NH3 capture properties of M2(dobpdc) complexes (M=Mg2+, Mn2+, Co2+, Ni2+, and Zn2+; dobpdc4−=4,4‐dioxidobiphenyl‐3,3‐dicarboxylate) that contain open metal sites is presented. The NH3 uptake of Mg2(dobpdc) at 298 K was 23.9 mmol g−1 at 1 bar and 8.25 mmol g−1 at 570 ppm, which are record high capacities at both pressures among existing porous adsorbents. The structural stability of Mg2(dobpdc) upon exposure to wet NH3 was superior to that of the other M2(dobpdc) and the frameworks tested. Overall, these results demonstrate that Mg2(dobpdc) is a recyclable compound that exhibits significant NH3 affinity and capacity, making it a promising candidate for real‐world NH3‐capture applications.
A metal–organic framework adsorbent with open metal sites is presented. It has record high capacities over a wide range of NH3 concentrations as well as an exceptional stability upon exposure to wet NH3.
•Proposed strategy is to vary the daily SOC reference level of a centralized battery in a microgrid to follow seasonal variation that is exhibited in solar PV output power. Thereby it reduces the ...required capacity of the battery at modest degradation rate.•The SOC level of the centralized battery is corrected to its reference value at the end of each day and during ‘SOC restoration period’ where grid interconnection line is at a low loading.•A rule-based strategy is used to control the magnitude and ramp rate of power flows in the grid interconnection link. This is achieved by the flexible control of the charging-discharge of the centralized battery.•The proposed control strategy has resulted in minimum battery capacity and also at the lowest SEI growth rate of the battery. Hence the life period of the battery is expected to increase.•The work is based on the real-time solar PV data measured at a high-frequency sampling rate in the authors’ laboratory. Such data of over several years for the analysis and design of the microgrid-centralized battery is rare to find in the public domain.
The focus of this paper is to develop a control strategy for a community battery bank in a grid-connected microgrid in which a significant level of photovoltaic generation is embedded. In order to minimize the capacity of the community battery, the power transfer capacity of the interconnection link between the microgrid and the external grid system is utilized to safe maximum levels. Through Empirical Mode Decomposition analysis of the net power flows of the microgrid, the daily and seasonal modes of the net power oscillations are identified as the two dominant low-frequency components. Whence a rule-based operational strategy is developed to control the power flows of the community battery via a novel dynamic referencing scheme for the state-of-charge of the battery bank. The battery control scheme counteracts the dominant daily and seasonal modes of oscillations of the net power. The numerical calculations performed for a case study shows that the proposed scheme leads to an approximately 16% decrease in the required battery capacity for particular growth rate of solid-electrolyte interphase film in the battery bank. The scheme does not require the forecasting of the net power, and thus, it has an increased degree of robustness when the community battery undertakes the power buffering task.
We demonstrate a practical way to identify the presence of a perovskite phase in rare-earth nickelates (RNiO3) using X-ray photoelectron spectroscopy (XPS). By varying the calcination temperature, we ...prepared RNiO3 powders with different degrees of chemical reaction. We found that perovskite RNiO3 becomes predominant after high-temperature calcination (≥1,000 °C) in X-ray diffraction and XPS (at Ni 3p and O 1s edges) measurements. While the observed spectra at the Ni 3p edge are similar for all powders, a sizable difference was observed in the O 1s-edge spectra depending on the calcination temperature. With the formation of a perovskite phase with a trivalent Ni3+ state, an XPS peak corresponding to oxygen ions in the perovskite lattice distinctly emerges. Our work shows that the Ni3+ state cannot be determined by analyzing the Ni 3p edge solely and rather, the O 1s edge should be simultaneously monitored for explicit identification.
•We report a way to identify a perovskite phase in rare-earth nickelates using XPS.•We prepared RNiO3 powders by varying their calcination temperatures.•We observed a perovskite RNiO3 phase in high-temperature calcined powders.•We monitored Ni 3p- and O 1s-edge XPS spectra in the as-calcined RNiO3 powders.•XPS peaks of oxygen ions in perovskite lattices emerge after high-temperature calcination.
Background and Aims
Therapies for chronic hepatitis B virus (HBV) infection are urgently needed because of viral integration, persistence of viral antigen expression, inadequate HBV‐specific immune ...responses, and treatment regimens that require lifelong adherence to suppress the virus. Immune mobilizing monoclonal T Cell receptors against virus (ImmTAV) molecules represent a therapeutic strategy combining an affinity‐enhanced T Cell receptor with an anti‐CD3 T Cell‐activating moiety. This bispecific fusion protein redirects T cells to specifically lyse infected cells expressing the target virus‐derived peptides presented by human leukocyte antigen (HLA).
Approach and Results
ImmTAV molecules specific for HLA‐A*02:01‐restricted epitopes from HBV envelope, polymerase, and core antigens were engineered. The ability of ImmTAV‐Env to activate and redirect polyclonal T cells toward cells containing integrated HBV and cells infected with HBV was assessed using cytokine secretion assays and imaging‐based killing assays. Elimination of infected cells was further quantified using a modified fluorescent hybridization of viral RNA assay. Here, we demonstrate that picomolar concentrations of ImmTAV‐Env can redirect T cells from healthy and HBV‐infected donors toward hepatocellular carcinoma (HCC) cells containing integrated HBV DNA resulting in cytokine release, which could be suppressed by the addition of a corticosteroid in vitro. Importantly, ImmTAV‐Env redirection of T cells induced cytolysis of antigen‐positive HCC cells and cells infected with HBV in vitro, causing a reduction of hepatitis B e antigen and specific loss of cells expressing viral RNA.
Conclusions
The ImmTAV platform has the potential to enable the elimination of infected cells by redirecting endogenous non‐HBV‐specific T cells, bypassing exhausted HBV‐specific T cells. This represents a promising therapeutic option in the treatment of chronic hepatitis B, with our lead candidate now entering trials.
•Empirical Mode Decomposition is adopted to decompose the wind power.•A definition of gap frequency to divide frequency components of power is proposed.•A new criteria is developed to present the ...smoothness of the wind power.•A model is developed to joint energy storage capacities and the smoothness of power.•The model has been developed into a long-term model and includes the cost of the HESS.
A new approach to determine the capacity of a supercapacitor-battery hybrid energy storage system (HESS) in a microgrid is presented. The microgrid contains significant wind power generation and the HESS is to smooth out the fluctuations in the delivered power to load. Using empirical mode decomposition (EMD) technique, historical wind power data is firstly analyzed to yield the intrinsic mode functions (IMF) of the wind power. From the instantaneous frequency-time profiles of the IMF, the gap frequency is identified and utilized in the design of filters which decompose the wind power into the high- and low-frequency components. Power smoothing is then achieved by regulating the output powers of the supercapacitors and batteries to negate the high- and low-frequency fluctuating power components, respectively. The degree of smoothness of the resulting power delivered to load is assessed in terms of a newly developed level of smoothness (LOS) criteria. A neural network model is then utilized to determine the storage capacity of the HESS through the minimization of an objective function which contains the costs of the HESS and that associated with the achieved LOS. Example of the design of a supercapacitor-lead acid battery HESS for an existing wind farm demonstrates the efficacy of the proposed approach.
•A physics-based Li-ion battery model is developed for power system planning studies.•Side reactions of the negative electrode are considered in an equivalent circuit model.•Parametric values of the ...circuit components are automatically updated.•Short- and long-term performance is predicted based on power flow at battery terminal.•Stored energy, degradation, and constraints are available for optimization of design.
A computationally-efficient and reliable method is developed to permit the simultaneous assessment of both the short- and long-term performance of lithium-ion battery in power system planning studies. Toward this end, a physics-based equivalent circuit model of the lithium-ion battery is derived in which side reaction-induced degradation of the battery is included. Whence a computational procedure is developed to enable the parametric values of the circuit elements in the equivalent circuit model to be automatically updated as the battery operates. The resulting model allows the increase in the internal resistance and the decrease in the energy storage capacity of the battery to be determined, based solely on the information of the power flows at the battery terminals. Dynamic simulation results obtained using the developed equivalent circuit model are shown to be in close agreement with those obtained from well-established electrochemical models, but at a much reduced computational burden.
Nanomaterials that can be reversibly or irreversibly changed in structures and properties by the influence of external chemical and physical stimuli are defined as smart nanomaterials ....
Background
Many engineering students fail to proceed through required prerequisite mathematics courses. Since these courses strongly influence engineering student attrition, we should examine to what ...degree these courses truly serve as prerequisites for following engineering coursework.
Purpose/Hypothesis
We examined two research questions: Which concepts and skills learned in calculus are applied in engineering statics and circuits homework assignments? How are calculus skills applied in engineering statics and circuits homework assignments?
Design/Method
This study analyzes the homework problems of two engineering courses—statics and circuits for nonmajors—using the mathematics‐in‐use method. These courses were chosen since they often require calculus as a direct prerequisite and are taken by most engineering majors. The mathematical content of each homework problem is carefully analyzed, with attention to alternative solution paths that may not match the instructor solution.
Results
Only 8% of statics problems and 20% of circuits for nonmajors problems applied calculus. Furthermore, these problems applied only the simplest calculus skills (e.g., integration of polynomials).
Conclusions
Circuits and statics apply relatively little calculus; most problems consist primarily of algebra. We may be able to modify prerequisite structures to ease or speed student progress.
Novel CAR T cells targeting mesothelin (MSLN) expressed on pancreatic cancer cells were developed to overcome the limit of the clinical efficacy of CAR T cell therapy for pancreatic cancer patients. ...Optimal single-chain variable fragments (scFv) binding to MSLN were selected based on the binding activity and the functional effectiveness of various scFv containing CAR-expressing T cells. Engineered MSLN CAR T cells showed successful anti-tumor activity specific to MSLN expression level. Furthermore, MSLN CAR T cells were evaluated for the anti-cancer efficacy in orthotopic mouse models bearing pancreatic cancer cells, MIA Paca-2, MSLN-overexpressed MIA Paca-2 or endogenously MSLN-expressing AsPC-1. Mice were randomized into control, mock treated, MS501 BBz treated, MS501 28z treated or MS501 28BBz treated group. Mice were monitored by weekly IVIS imaging and tumors were harvested and analyzed by immunohistochemical analyses. MSLN CAR T cells produced the therapeutic effect in orthotopic animal models with complete remission in significant number of mice. Histopathological analysis indicated that CD4+ and CD8+ MSLN CAR T cells infiltrated pancreatic tumor tissue and led to cancer cell eradication. Our results demonstrated the anti-tumor efficacy of MSLN CAR T cell therapy against pancreatic cancer, suggesting its therapeutic potential.
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