High Peak Rates Research Articles

Characterization of LiNi0.8Co0.15Al0.05O2 cathode material synthesized via co-precipitation method

Abstract LiNi0.8Co0.15Al0.05O2 cathode material was synthesized using the co-precipitation method, and the effect of synthesis conditions on powder properties was studied. The results indicate that adjusting the pH value and complexing agent concentration during the reaction process can effectively control the precipitation process. The obtained hydroxide precursor is petallike, and the morphology of the cathode material powder after high-temperature sintering is well-dispersed spherical particles. The changes in the sintering system can significantly affect the crystallization process and crystal structure of cathode materials. As the sintering temperature increases, the peak rate I (003)/I (104) significantly decreases, while the R value increases. With the prolongation of sintering time, I (003)/I (104) first increases and then decreases, and the R value first decreases and then increases. After sintering at 750°C × 12 h, the cathode material has the highest peak rate and the lowest R value, indicating the lowest degree of cation mixing, higher structural integrity and the highest electrochemical activity at this time.

Investigations on a Spark Ignition Engine, Part II: Impact of Hydrogen Addition and Compression Ratio on a Biogas-Fuelled Engine

Performance, emissions and combustion were studied using a spark ignition engine modified from a single-cylinder diesel engine with varying compression ratios and hydrogen addition. When the compression ratio increases, there is a slight increase in brake power and thermal efficiency. There is a small increase in brake power and brake thermal efficiency when the compression ratio is above 13:1. Increased emissions of nitric oxide, hydrocarbon, and carbon monoxide were observed at compression ratios above 13:1. Leaner mixtures, brake power and brake thermal efficiency are lowered. Spark timing is retarded as the compression ratio rises which results in high peak pressure and rate of heat release. At a compression ratio of 13:1, a small amount of hydrogen (15% on an energy basis) was added along with biogas. The lean limit of biogas combustion and the combustion rate are greatly increased by the addition of hydrogen. In addition, there was a rise in brake power and thermal efficiency. The levels of hydrocarbons were significantly reduced. Nitric oxide emissions did not rise as a result of the use of the retarded ignition timing. The effect of two throttle conditions on spark ignition engines using biogas as fuel is presented as Part I of this study.

Hazard rate for postoperative recurrence in patients with hepatocellular carcinoma at Barcelona Clinic Liver Cancer stage 0 or A1: A multicenter observational study

Surgical treatment is the first-line treatment for patients with Barcelona Clinic Liver Cancer (BCLC) stage 0 or A1 hepatocellular carcinoma (HCC), and postoperative monitoring improves long-term survival. We aimed to establish a reasonable short-interval follow-up duration for patients with HCC. The cohort for this retrospective study included 1396 HCC patients with BCLC stage 0 or A1 disease who underwent curative resection from 2013 to 2016 at five centers in China. Hazard rates for recurrence were calculated using the hazard function. The recurrence rates in patients with BCLC stage 0 and A1 HCC were 46.4% and 58.0%, respectively. The hazard curve for stage 0 patients was relatively flat, and the hazard rate was consistently low (peak hazard rate 0.0163). The hazard rate curve for recurrence was initially high (peak hazard rate 0.0441) in patients with BCLC stage A1 disease and showed a rapid decreasing trend within 1year, followed by a slow decreasing trend, reaching a low level (<0.0163) at approximately 36months. The time to low risk was 47, 41, and 51months in patients with cirrhosis, hepatitis B virus (HBV) infection, and satellite lesions, respectively. A short-interval follow-up of 1year is sufficient for HCC patients with BCLC stage 0 disease, whereas a short-interval follow-up time of 3years should be considered for patients with stage A1 disease. The follow-up period should be appropriately prolonged for patients with cirrhosis, HBV infection, and satellite lesions.

A Novel High-Power Hybrid DC Breaker Based on Compound Power Electronic Switch With Integrated Commutation Ability

Medium voltage dc power system has the characteristics of low line impedance, resulting in high peak and fast rise rate of the fault current. For example, the current in an onboard 10 kV dc grid can rise to more than 40 kA in 3 ms after the failure. Therefore, it is necessary to configure dc circuit breaker with high current breaking capacity. In this letter, a novel high-power hybrid dc breaker based on integrated commutation compound power electronic switch is proposed. By giving full play to the complementary advantages of insulated gate bipolar transistor (IGBT) and integrated gate-commutated thyristor (IGCT), and skillfully integrating the commutation function into the power electronic switch, the proposed dc breaker has the characteristics of low cost, compact, high performance, and can also play a role in current limiting. The working principle of the proposed scheme is described in detail, and a 10-kV prototype with 40 kA current breaking ability is built to verify its feasibility.

Effect Of Hip Strength On Backwards Single-Legged Jump-Landing Vertical Ground Reaction Force

Commonly proposed risk factors for lower-extremity injury include high vertical peak ground reaction force (vGRF) and rate of force development (vRFD) during a backward single-legged jump-landing (SLJL), deficient hip external rotation (ER) and abduction (ABD) strength, and fatigue. PURPOSE: The purpose of this study was to evaluate the effect of ER and ABD on vGRF and vRFD following SLJL. It was hypothesized low ER and ABD coupled with fatigue would be associated with high vGRF and vRFD. METHODS: Twenty-seven healthy males (n = 10) and females (n = 17) (24.0 ± 2.8 y, 1.73 ± .08 m, 75.0 ± 14.0 kg) participated in this repeated measure study which included rest (R) and fatigue (F) protocols. ER and ABD isometric torque (Nm·kg-1) on the dominate leg were measured using a handheld dynamometer. For R, participants performed SLJL (PRE), rested for 5 minutes, and then reperformed SLJL (POST). For F, participants performed SLJL (PRE), a 7 minute fatigue protocol, and then reperformed SLJL (POST). R and F were performed in a random order. SLJL was performed by jumping backward off the test leg over a .15 m hurdle, landing on the test leg on a force plate, and stabilizing quickly. vGRF (N·kg-1) and vRFD (N·kg-1·s-1) were calculated. Participants were stratified into high-strength (HS) and low-strength (LS) groups using ER and ABD and a k-means cluster analysis. Linear mixed-models were used to assess the effect of group and protocol on vGRF and vRFD with Bonferroni corrected post-hoc tests. Significance was initially set to p < .05. RESULTS: 16 participants were stratified into HS (ER = 4.3 ± .9, ABD = 8.3 ± 1.0) and 11 into LS (ER = 3.3 ± 1.0, ABD = 5.8 ± .9). There was no effect of group on vGRF (HS = 2.98 ± .59, LS = 3.03 ± .59, p = .627) or vRFD (HS = 35.8 ± 19.8, LS = 37.1 ± 18.9, p = .735). HS and LS did not responded differently to R and F for vGRF (p = .694) or vRFD (p = .899). Further, with all subjects pooled, they did not respond differently to R and F for vGRF (p = .081), but they did for vRFD (p < .001). vRFD POST F (41.2 ± 22.3) was higher than PRE F (34.9 ± 22.3, p < .001) and POST R (32.9 ± 22.3, p < .001). CONCLUSION: There is no effect of ER and ABD on vGRF and vRFD and vGRF does not increase with fatigue, but vRFD does increase with fatigue. This may suggest a reduction in the ability to quickly attenuate forces when fatigued and may potentially increase the risk for injury.

Abstract 259: Outcomes of Targeted Temperature Management in Patients with Out-of-hospital Refractory Ventricular Fibrillation/ventricular Tachycardia Cardiac Arrest

Background: Current guidelines recommend use of targeted temperature management (TTM) with goal between 32 and 36°C for all comatose adult patients with ROSC after cardiac arrest. However, refractory cardiac arrest with prolonged hypoperfusion, may cause passive cooling below goal temperature. The impact of this passive cooling and subsequent cooling strategies remains unknown. This study aims to describe the association between passive intra-arrest cooling and survival in patients suffering refractory VF/VT cardiac arrest treated with the University of Minnesota extracorporeal cardiopulmonary resuscitation (ECPR) protocol. Methods: Between December 2015 and October 2019, consecutive adult patients with refractory VF/VT arrest requiring ongoing CPR were transported by EMS to the CCL where ECPR, coronary angiography, and PCI were performed, as appropriate. TTM was initiated with goal temperature of 34°C unless clinically significant bleeding occurred, where a goal of 36°C was used. Patient and arrest characteristics, temperature data, and survival were collected retrospectively. Results: Data was gathered for 153 consecutive patients transferred for ECPR; 12 were excluded due to death in CCL prior to TTM. Of the remaining patients, 63 (41%) survived to discharge, where 55 (36%) had CPC scores of 1-2. Among deceased patients, 25 died from acute brain death while 47 died from other causes. Patients with CPC 1-2 had an initial temperature of 34.1°C versus 32.7°C in patients developing acute brain death (p=0.002). Survivors had shorter (p=0.0001) CPR time (52 minutes) versus deceased patients (65 minutes). If the initial temperature was below goal, patients were actively warmed to goal due to bleeding risk with ECPR. Survival to hospital discharge with CPC 1-2 was associated with lower peak warming rate compared with acute brain death (0.37°C/hr vs 0.69°C/hr; p=0.014) Conclusions: Survivors with CPC 1-2 after refractory VF/VT cardiac arrest and ECPR have preserved initial temperatures compared to more severe passive cooling in patients with acute brain death. This may be due to shorter duration of CPR. However, patients with acute brain death were noted to have higher peak rate of rewarming during TTM.

Distributed Learning and Coordination in Cognitive Infrastructureless Networks of Unknown Size

The cognitive infrastructureless network has received significant attention to reduce signaling load in next-generation networks, which are expected to be ultradense with very high peak rate but relatively lower expected traffic per user. Research in this area has evolved from the distributed algorithms requiring prior knowledge of the number of secondary users (SUs) $U$ to the existing algorithms, which can estimate $U$ independently by counting the number of collisions. The major drawback of these algorithms is the large number of collisions leading to wastage of power and bring down the effective life of battery operated SUs. In this paper, we develop algorithms that learn faster and incurs fewer collisions. We assume unknown $U$ with two types of networks: fixed $U$ (i.e., static networks) and time-varying $U$ (i.e., dynamic networks). Proposed algorithms are based on the multiplayer multi-armed bandit (MAB) approach. We show that the proposed algorithms offer constant regret (i.e., throughput loss) with high probability and sub-linear regret in static and dynamic networks, respectively. Theoretical analysis, simulation, and experimental results demonstrate the efficacy of the proposed algorithms in terms of vacant spectrum utilization, regret, and the number of collisions. Fewer collisions significantly increase the operational life of SUs.

Tidal Disruption Events: The Role of Stellar Spin

Abstract The tidal force from a supermassive black hole can rip apart a star that passes close enough in what is known as a Tidal Disruption Event (TDE). Typically, half of the destroyed star remains bound to the black hole and falls back on highly eccentric orbits, forming an accretion flow that powers a luminous flare. In this paper, we use analytical and numerical calculations to explore the effect of stellar rotation on the fallback rate of material. We find that slowly spinning stars (Ω* ≲ 0.01Ωbreakup) provide only a small perturbation to fallback rates found in the non-spinning case. However, when the star spins faster, there can be significant effects. If the star is spinning retrograde with respect to its orbit, the tidal force from the black hole has to spin down the star first before disrupting it, causing delayed and sometimes only partial disruption events. However, if the star is spinning prograde, this works with the tidal force and the material falls back sooner and with a higher peak rate. We examine the power-law index of the fallback curves, finding that in all cases the fallback rate overshoots the canonical t −5/3 rate briefly after the peak, with the depth of the overshoot dependent on the stellar spin. We also find that, in general, the late time evolution is slightly flatter than the canonical t −5/3 rate. We therefore conclude that considering the spin of the star may be important in modeling observed TDE light curves.

Synchronization Requirements for 5G: An Overview of Standards and Specifications for Cellular Networks

This article studies the importance, requirements, and trends of synchronization for radio communications. Fifth-generation (5G) wireless communication is expected to be a forthcoming revolution in the wireless world, achieving communications with a high peak rate, high spectral efficiency, multiple device connectivity, low end-to-end latency, and high reliability. From a historical perspective, we review the synchronization required for first-generation (1G) to fourth-generation (4G) mobile communications to achieve performance metrics and provide various new services. New synchronization specifications and standards may depend on specific new applications and are, therefore, more service oriented. This article surveys the progress and trends of synchronization requirements in standardizations and specifications.

Optimization of LTE Network Coverage

The trend of mobile, broadband and IP is becoming more and more prominent. Mobile communication technology is now in acritical period in the evolution of network technology. As such, LTE (Long Term Evolution) comes to light. LTE serves as a unified standardfor the new generation of mobile communications, equipped with high spectral efficiency, high peak rate, high mobility, flat networkarchitecture and other advantages. Huawei has played a very important role in the commercialization of LTE. As a sponsor of NGMN,Huawei has been actively involved in the research of some key projects of NGMN, such as network self-optimization, system architectureand Network performance evaluation and so on. This paper mainly introduces the problems encountered in the optimization of LTEnetwork coverage, the practical problems encountered by the LTE project team in Qingdao and the analysis and solutions to the problems.At the same time, this paper discusses in detail on the LTE network optimization process.

Amplification Channel for Avalanche Photodiode Signals Purposed for Spectrometric Measurements under High Peak Rates

A method of amplification and shaping of analog signals produced by a large-capacitance signal source is proposed. This method is optimized for reaching the highest signal/noise ratio, and, along with that, it allows for recognizing signals that arrive with a small time interval. An amplifying channel is designed that implements the proposed method. This channel is purposed for amplification of avalanche photodiode signals in detectors based of fast scintillators. The structure of the amplifying channel, the principle of recovering the shape of the input signal, and the basic circuit design solutions used in the developed amplifier are described.

Storm Water and Contamination Control Efficiency Evaluation for Construction of a Neighborhood Project Using Low Impact Development

Urban flooding and water pollution are urgent problems to be solved in urban development. The improvement of urban drainage and water quality in urban construction using ecological measures is an important research task. Low impact development (LID) is a new concept in soil and water conservation aimed at improving urban rainwater use and reducing non-point source pollution. This paper discusses the best management practices (BMPs) related to storm water and contamination control efficiency by comparing pre-development and post-development neighborhoods (both conventional and LID designs). The study area was Weatherford, Oklahoma, United States. The results showed that conventional design had the lowest total runoff but highest peak rate, infiltration trenches with rain barrels were more efficient than bioswales, and the use of LID design would reduce total runoff and peak rate significantly. However, LID design would increase construction and annual maintenance fees.

Design of efficient wireless communication system with improved SER using different relay environment

It is very challenging to design an efficient wireless communication system. It is because of many factors, affecting the performance of a typical wireless communication system. With all these years’ rapid development in wireless communication, high demands for broadband mobile wireless communications and the emergence of new wireless multimedia applications have constituted the motivation to the development of broadband wireless access technologies. The long term evolution (LTE) system has been specified by the third generation partnership project (3GPP) on the way towards fourth-generation (4G) mobile to ensure 3GPP keeping the dominance of the cellular communication technologies. LTE-advanced (LTE-A) is the project name of the evolved version of LTE that is being developed by 3GPP. LTE-A will meet or exceed the requirements of the International Telecommunication Union (ITU) for the 4G radio communication standard. LTE-A is being specified initially as part of the 3GPP specifications. Where the current generation of mobile telecommunication networks are collectively known as 3G (for “third generation”), LTE is marketed as 4G. In this paper, LTE-A WINNER MIMO uses orthogonal frequency division multiplexing (OFDM) for the downlink that is, from the base station to the terminal. OFDMA meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates. The multiple access schemes in LTE downlink uses orthogonal frequency division multiple access (OFDMA). Power saving in transmission is an extensive issue for the multiple access techniques used in LTE, therefore in this paper, an important transmission factor SER for OFDMA system, is considered. This paper provides comparison of SER performance versus SNR of OFDMA system for different relay environment in WINNER, MIMO LTE-A.

Frame Structure Design and Analysis for Millimeter Wave Cellular Systems

The millimeter-wave (mmWave) frequencies have attracted considerable attention for fifth generation (5G) cellular communication as they offer orders of magnitude greater bandwidth than current systems. However, the medium access control (MAC) layer may need to be significantly redesigned to support the highly directional transmissions, and the demand for ultra-low latencies and high peak rates expected in mmWave communication. To address these challenges, we present a novel mmWave MAC layer frame structure with a number of enhancements, including flexible, highly granular transmission times, dynamic control signal locations, extended messaging, and the ability to efficiently multiplex directional control signals. Analytic formulas are derived for the utilization and control overhead as a function of control periodicity, number of users, traffic statistics, signal-to-noise ratio, and antenna gains. Importantly, the analysis can incorporate various front-end MIMO capability assumptions-a critical feature of mmWave. Under realistic system and traffic assumptions, the analysis reveals that the proposed flexible frame structure design offers significant benefits over designs with fixed frame structures similar to current 4G long-term evolution. It is also shown that the fully digital beamforming architectures offer significantly lower overhead compared with analog and hybrid beamforming under equivalent power budgets.

Dependence of heating rates of thermal activation on thermal activation characteristics of 110 °C TL peak of quartz: A simulation approach

Abstract This work was undertaken to investigate heating rates effect of thermal activation on the thermal activation characteristic (TAC) by a way of numerical simulation of an existing model. This was done by monitoring charge distributions among trapping states (electron and hole traps), both immediately after thermal activation and after irradiation of test dose. Previously observed ‘early activation’ and ‘late activation’ of TACs have been numerically observed in this work by following the exact experimental procedures of varying heating rates of thermal activation that produced them. Indirect thermal transfer signal from high temperature-TL peak at the end of thermal activation was observed to also contribute to the sensitization in the TACs, apart from the popular pre-dose effect. This contribution to the TACs from indirect thermal transfer signal from high temperature-TL peak increases with heating rate utilised for thermal activation. Recombination rate of evicted electron from high temperature-TL peak with holes during the thermal activation resulted into (i) increased sensitization with heating rates of thermal activation and (ii) direct dependence of temperature at glow-peak maximum intensity ( T m ) of high temperature TL peak and heating rates of thermal activation on the peak position of the TACs peak. The impact of the electrons loss to recombination during the short irradiation increases with the heating rates of the thermal activation. The overall results have been employed to shed more light on the pre-dose phenomenon and its applications in dating.

Investigation of non-isothermal and isothermal gasification process of coal char using different kinetic model

Isothermal and non-isothermal gasification kinetics of coal char were investigated by using thermogravimetric analysis (TGA) in CO2 atmosphere, and the experimental data were interpreted with the aids of random pore model (RPM), unreacted shrinking core model (URCM) and volume model (VM). With the increase of heating rate, gasification curve moves into high temperature zone and peak rate of gasification increases; with the increase of gasification temperature, gasification rate increases and the total time of gasification is shortened. The increase of both heating rate and gasification temperature could improve gasification process of coal char. Kinetics analysis indicates that experimental data agree better with the RPM than with the other two models. The apparent activation energy of non-isothermal and isothermal gasification of coal char using RPM is 193.9kJ/mol and 212.6kJ/mol respectively, which are in accordance with reported data. Gasification process of coal char under different heating rates and different temperatures are predicted by the RPM derived in this study, and it is found that the RPM predicts the reaction process satisfactorily.

Multiobjective Signal Processing Optimization: The way to balance conflicting metrics in 5G systems

The evolution of cellular networks is driven by the dream of ubiquitous wireless connectivity: any data service is instantly accessible everywhere. With each generation of cellular networks, we have moved closer to this wireless dream; first by delivering wireless access to voice communications, then by providing wireless data services, and recently by delivering a Wi-Fi-like experience with wide-area coverage and user mobility management. The support for high data rates has been the main objective in recent years [1], as seen from the academic focus on sum-rate optimization and the efforts from standardization bodies to meet the peak rate requirements specified in IMT-Advanced. In contrast, a variety of metrics/objectives are put forward in the technological preparations for fifth-generation (5G) networks: higher peak rates, improved coverage with uniform user experience, higher reliability and lower latency, better energy efficiency (EE), lower-cost user devices and services, better scalability with number of devices, etc. These multiple objectives are coupled, often in a conflicting manner such that improvements in one objective lead to degradation in the other objectives. Hence, the design of future networks calls for new optimization tools that properly handle the existence of multiple objectives and tradeoffs between them.

Kinetic Modeling of the Monoamine Oxidase B Radioligand [11C]SL25.1188 in Human Brain with High-Resolution Positron Emission Tomography

This article describes the kinetic modeling of [(11)C]SL25.1188 ([(S)-5-methoxymethyl-3-[6-(4,4,4-trifluorobutoxy)-benzo[d]isoxazol-3-yl]-oxazolidin-2-[(11)C]one]) binding to monoamine oxidase B (MAO-B) in the human brain using high-resolution positron emission tomography (PET). Seven healthy subjects underwent two separate 90- minute PET scans after an intravenous injection of [(11)C]SL25.1188. Complementary arterial blood sampling was acquired. Radioactivity was quickly eliminated from plasma with 80% of parent compound remaining at 90 minutes. Metabolites were more polar than the parent compound. Time-activity curves showed high brain uptake, early peak and washout rate consistent with known regional MAO-B concentration. A two-tissue compartment model (2-TCM) provided better fits to the data than a 1-TCM. Measurement of total distribution volume (VT) showed very good identifiability (based on coefficient of variation (COV)) for all regions of interest (ROIs) (COV(VT)<8%), low between-subject variability (∼20%), and quick temporal convergence (within 5% of final value at 45 minutes). Logan graphical method produces very good estimation of VT. Regional VT highly correlated with previous postmortem report of MAO-B level (r(2)= ≥ 0.9). Specific binding would account from 70% to 90% of VT. Hence, VT measurement of [(11)C]SL25.1(1)88 PET is an excellent estimation of MAO-B concentration.

Lagrangian Relaxation Based Production Optimization of Tight-formation Wells

Dry and semi-dry tight formation gas wells normally share the characteristic production profile defined by an initial high production, with an early steep decline and subsequent low pseudo steady-state gas rates. Small volumes of co-produced liquids will, even for dry gas wells, eventually bring the wells into the state of liquid loading, causing erratic unpredictable production rates deteriorating the performance of the wells. This state of the wells can be prevented by performing short shut-ins when the gas rate falls below the minimum rate needed to avoid liquid loading. Multi-well shut-ins may however lead to very high and low peak rates, possibly causing problems for the capacity of shared surface systems or lower and upper bounds on the total rate in a production plan. This paper presents a Lagrangian relaxation based scheme for scheduling of shut-in times for late-life tight formation gas wells with a shared gathering system. The proposed scheme includes a QP formulation for solving the Lagrangian dual, together with an aggregated construction and improvement heuristic for generating primal feasible solutions from the solution of the Lagrangian. We include several test examples to demonstrate the efficiency of the proposed decomposable scheme.

PAPR Reduction for 3FPP LTE OFDMA System

LTE (long term evolution) is come to meet our desired high speed data communication.LTE is the last step toward the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile telephone networks. Where the current generation of mobile telecommunication networks are collectively known as 3G (for third generation), LTE is marketed as 4G. LTE uses Orthogonal Frequency Division Multiplexing (OFDM) for the downlink - that is, from the base station to the terminal. OFDMA meets the LTE requirement for spectrum flexibility and enables cost-efficient solutions for very wide carriers with high peak rates. However, one of the main drawbacks of the OFDMA modulation technique is the large peak-to-average power ratio (PAPR) of the transmitting signals. This high PAPR causes interference when the OFDM signals are passed through an amplifier which does not have enough linear range. Several PAPR reduction techniques such as magnitude clipping, block coding, and partial transmit sequence (PTS) and pulse shaping have been proposed to reduce the PAPR. In this paper, we evaluate a clipping based PAPR reduction technique. The complementary cumulative distribution function (CCDF) of the PAPR, which can be used to evaluate the PAPR reduction performance, is derived for OFDMA signals.