Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

Shrinkage defects can be formed easily at Critical location during low pressure die casting (LPDC) of aluminum alloy cylinder body. It has harmful effect on the products. Mold fi lling and solidifi cation process of a cylinder body was simulated by using of Z-CAST software. The casting method was improved based on the simulation results. In order to create effective feeding passage, the structure of casting was modifi ed by changing the location of strengthening ribs at the bottom, without causing any adverse effect on the part’s performance. Inserting copper billet at suitable location of the die is a valid way to create suitable solidifi cation sequence that is benefi cial to the feeding. Using these methods, the shrinkage defect was completely eliminated at the critical location

Simulation of Grid-connected Wind Generator in Wind Power Flow Optimization System Experiment Platform

AbstractA simulation system of grid-connected wind power generator used for research and development of wind power flow optimization system is analysed and designed. It's key component parts, connection structure and working principle are introduced. As a core module, the DC/AC power condition system (DAPCS) is emphatically discussed and described with respect to topology, modeling and control strategy. Experimental results indicate that the simulated wind power generator can output fluctuant power meeting the demand of research and develop of wind power flow optimization system

Distributed Inference and Query Processing for RFID Tracking and Monitoring

In this paper, we present the design of a scalable, distributed stream processing system for RFID tracking and monitoring. Since RFID data lacks containment and location information that is key to query processing, we propose to combine location and containment inference with stream query processing in a single architecture, with inference as an enabling mechanism for high-level query processing. We further consider challenges in instantiating such a system in large distributed settings and design techniques for distributed inference and query processing. Our experimental results, using both real-world data and large synthetic traces, demonstrate the accuracy, efficiency, and scalability of our proposed techniques.Comment: VLDB201

Intercalated water layers promote thermal dissipation at bio–nano interfaces

The increasing interest in developing nanodevices for biophysical and biomedical applications results in concerns about thermal management at interfaces between tissues and electronic devices. However, there is neither sufficient knowledge nor suitable tools for the characterization of thermal properties at interfaces between materials of contrasting mechanics, which are essential for design with reliability. Here we use computational simulations to quantify thermal transfer across the cell membrane–graphene interface. We find that the intercalated water displays a layered order below a critical value of ∼1 nm nanoconfinement, mediating the interfacial thermal coupling, and efficiently enhancing the thermal dissipation. We thereafter develop an analytical model to evaluate the critical value for power generation in graphene before significant heat is accumulated to disturb living tissues. These findings may provide a basis for the rational design of wearable and implantable nanodevices in biosensing and thermotherapic treatments where thermal dissipation and transport processes are crucial.MIT-China seed fundNational Natural Science Foundation of China (Grant No. 11472150)National Natural Science Foundation of China (Grant No. 2015CB351900)United States. Office of Naval Research (Grant No. N00014-16-1-233)United States. Office of Naval Research. Presidential Early Career Award for Scientists and Engineers (Grant No. N00014-10-1-0562)United States. Air Force. Office of Scientific Research. FATE MURI (Grant No. FA9550-15-1-0514)United States. Defense Advanced Research Projects AgencyMIT Energy InitiativeNational Science Foundation (U.S.). Materials Research Science and Engineering Centers (Program) (award number DMR-0819762

Calcium-tin alloys as anodes for rechargeable non-aqueous calcium-ion batteries at room temperature

Rechargeable calcium batteries possess attractive features for sustainable energy-storage solutions owing to their high theoretical energy densities, safety aspects and abundant natural resources. However, divalent Ca-ions and reactive Ca metal strongly interact with cathode materials and non-aqueous electrolyte solutions, leading to high charge-transfer barriers at the electrode-electrolyte interface and consequently low electrochemical performance. Here, we demonstrate the feasibility and elucidate the electrochemical properties of calcium-tin (Ca–Sn) alloy anodes for Ca-ion chemistries. Crystallographic and microstructural characterizations reveal that Sn formed from electrochemically dealloying the Ca–Sn alloy possesses unique properties, and that this in-situ formed Sn undergoes subsequent reversible calciation/decalciation as CaSn(3). As demonstration of the suitability of Ca–Sn alloys as anodes for Ca-ion batteries, we assemble coin cells with an organic cathode (1,4-polyanthraquinone) in an electrolyte of 0.25 M calcium tetrakis(hexafluoroisopropyloxy)borate in dimethoxyethane. These electrochemical cells are charged/discharged for 5000 cycles at 260 mA g(−1), retaining a capacity of 78 mAh g(−1) with respect to the organic cathode. The discovery of new class of Ca–Sn alloy anodes opens a promising avenue towards viable high-performance Ca-ion batteries

Establishing a Stable Anode–Electrolyte Interface in Mg Batteries by Electrolyte Additive

Simple magnesium salts with high electrochemical and chemical stability and adequate ionic conductivity represent a new-generation electrolyte for magnesium (Mg) batteries. Similar to other Mg electrolytes, the simple-salt electrolyte also suffers from high charge-transfer resistance on the Mg surface due to the adsorbed species in the solution. In the current study, we built a model Mg cell system with the Mg[B(hfip)4]2/DME electrolyte and Chevrel phase Mo6S8 cathode, to demonstrate the effect of such anode–electrolyte interfacial properties on the full-cell performance. It was found that the cell required additional activation cycles to achieve its maximal capacity. The activation process is mainly attributed to the conditioning of the anode–electrolyte interface, which could be boosted by introducing an additive amount of Mg(BH4)2 to the Mg[B(hfip)4]2/DME electrolyte. Electrochemical and spectroscopic analyses revealed that the Mg(BH4)2 additive helps to remove the native oxide layer and promotes the formation of a solid electrolyte interphase layer on Mg. As a result, the full cell with the additive-containing electrolyte delivered a stable capacity from the second cycle onward. Further battery tests showed a reversible cycling for 600 cycles and an excellent rate capability, indicating good compatibility of the Mg(BH4)2 additive. The current study not only provides fundamental insights into the interfacial phenomena in Mg batteries but also highlights the facile tunability of the simple-salt Mg electrolytes

Combining Quinone‐Based Cathode with an Efficient Borate Electrolyte for High‐Performance Magnesium Batteries

Rechargeable magnesium batteries are gaining attention as promising candidates for large-scale energy storage applications because of their potentially high energy, safety and sustainability. However, the development of Mg batteries is impeded by the lack of efficient cathode materials and compatible electrode-electrolyte combinations. Herein, we demonstrate a new poly(1,4-anthraquinone)/Ketjenblack composite (14PAQ@KB) in combination with non-corrosive magnesium tetrakis(hexafluoroisopropyloxy) borate Mg[B(hfip)(4)](2) (hfip=OC(H)(CF3)(2)) electrolyte towards high-energy and long-lifespan Mg batteries. This combination exhibits prominent electrochemical performance including a maximum discharge capacity of 242 mA h g(-1) (approximately 93 % of the theoretical capacity), superior cycling stability (81 mA h g(-1) after 1000 cycles), and excellent rate capability (120 mA h g(-1) at 5 C)

Case report: Phosphoinositide 3-kinase inhibitor with fulvestrant in a patient with ER+/HER2- metastatic breast carcinoma induced fatal arrhythmias: a preventable event?

Phosphoinositide 3-kinase (PI3K) inhibitors have shown synergistic anticancer effects with endocrine therapy against ER+/PIK3CA-mutated breast cancer. PI3K inhibitors for cancer therapy are becoming more common. There is an increasing need to understand their cardiac adverse events. In this report, we describe the features of near-fatal mixed arrhythmias in a patient who was undergoing a phase Ib clinical study of PI3Kα inhibitor with fulvestrant. Subsequently, the patient survived by cardiopulmonary resuscitation and therefore did not die. This case highlights that PI3K inhibitors can induce QT/QTc prolongation and predispose patients to TdP. The combination of QT/QTc prolongation in combination with prolonged cardiac repolarization, such as an AV block during treatment with PI3Kα inhibitor, may aggravate the occurrence of TdP. It is likely to be a safer strategy to adjust the standard of discontinuing drugs and continuing drugs (QTc interval was <500 and <60 ms at baseline) or choose other types of alternative treatment options. This report provided some ideas for clinicians to identify early and prevent the occurrence of fatal arrhythmias during anticancer treatment

Polyoxometalate Modified Separator for Performance Enhancement of Magnesium–Sulfur Batteries

The magnesium–sulfur (Mg‐S) battery has attracted considerable attention as a candidate of post‐lithium battery systems owing to its high volumetric energy density, safety, and cost effectiveness. However, the known shuttle effect of the soluble polysulfides during charge and discharge leads to a rapid capacity fade and hinders the realization of sulfur‐based battery technology. Along with the approaches for cathode design and electrolyte formulation, functionalization of separators can be employed to suppress the polysulfide shuttle. In this study, a glass fiber separator coated with decavanadate‐based polyoxometalate (POM) clusters/carbon composite is fabricated by electrospinning technique and its impacts on battery performance and suppression of polysulfide shuttling are investigated. Mg–S batteries with such coated separators and non‐corrosive Mg[B(hfip)4]2 electrolyte show significantly enhanced reversible capacity and cycling stability. Functional modification of separator provides a promising approach for improving metal–sulfur batteries