Capacity Analysis on Distributed Antenna System with Imperfect CSI over Rayleigh Fading Channel

Considering that perfect channel state information(CSI)is hard to obtain in practice,the capacity of downlink distributed antennas system(DAS)with imperfect CSI is analyzed over Rayleigh fading channel.Based on the performance analysis,using the probability density function and numerical calculation,an accurate closedform expression of ergodic capacity of downlink DAS under imperfect CSI is derived.It includes the one under perfect CSI as a special case.This theoretical expression can provide good performance evaluation for downlink DAS for both perfect and imperfect CSI due to its accuracy.Simulation results indicate that the theoretical analysis agrees well with the corresponding simulation,and the capacity can be increased effectively by decreasing the estimation error and/or path loss.

Capacity Analysis and Information Optimization of WSDM

Wireless statistic division multiplexing (WSDM) is a multiplexing scheme that transmits multiple signals simultaneously in the same frequency band over wireless channels. Based on the Shannon capacity of band-limited waveform AWGN channel with input power constraint, we obtain channel capacity of WSDM. Compared to time division multiplexing (TDM), frequency division multiplexing (FDM), and code division multiplexing (CDM), WSDM is more effective in raising spectrum efficiency. What’s more, we propose information optimization method to separate time-frequency mixed signals. Computer simulations also verify that the proposed method is feasible and performs better than traditional algorithms.

Prediction of Health Level of Multiform Lithium Sulfur Batteries Based on Incremental Capacity Analysis and an Improved LSTM

Capacity estimation plays a crucial role in battery management systems,and is essential for ensuring the safety and reliability of lithium-sulfur(Li-S)batteries.This paper proposes a method that uses a long short-term memory(LSTM)neural network to estimate the state of health(SOH)of Li-S batteries.The method uses health features extracted from the charging curve and incre-mental capacity analysis(ICA)as input for the LSTM network.To enhance the robustness and accuracy of the network,the Adam algorithm is employed to optimize specific hyperparameters.Experimental data from three different groups of batteries with varying nominal capac-ities are used to validate the proposed method.The results demonstrate the effectiveness of the method in accurately estimating the capacity degradation of all three batteries.Also,the study examines the impact of different lengths of network training sets on capacity estimation.The results reveal that the ICA-LSTM model achieves a prediction accuracy of mean absolute error 4.6%and mean squared error 0.21%with three different training set lengths of 20%,40%,and 60%.The analysis demonstrates that the lightweight model maintains high SOH estimation accu-racy even with a small training set,and exhibits strong adaptive and generalization capabilities when applied to different Li-S batteries.Overall,the proposed method,supported by experimental validation and analysis,demonstrates its efficacy in ensuring accurate and reliable SOH estimation,thereby enhancing the safety and per-formance of Li-S batteries.Index Terms—Adam algorithm,incremental capacity analysis,Li-S battery,long short-term memory,state of health.

Analysis of Capacity Decay, Impedance, and Heat Generation of Lithium-ionBatteries Experiencing Multiple Simultaneous Abuse Conditions

Abuse of Lithium-ion batteries,both physical and electrochemical,can lead to significantly reduced operational capabilities.In some instances,abuse can cause catastrophic failure,including thermal runaway,combustion,and explosion.Many different test standards that include abuse conditions have been developed,but these generally consider only one condition at a time and only provide go/no-go criteria.In this work,different types of cell abuse are implemented concurrently to determine the extent to which simultaneous abuse conditions aggravate cell degradation and failure.Vibrational loading is chosen to be the consistent type of physical abuse,and the first group of cells is cycled at different vibrational frequencies.The next group of cells is cycled at the same frequencies,with multiple charge pulses occurring during each discharge.The final group of cells is cycled at the same frequencies,with a partial nail puncture occurring near the beginning of cycling.The results show that abusing cells with vibrational loading or vibrational loading with current pulses does not cause a significant decrease in operational capabilities while abusing cells with vibrational loading and a nail puncture drastically reduces operational capabilities.The cells with vibration only experience an increase in internal resistance by a factor of 1.09–1.26,the cells with vibration and current pulses experience an increase in internal resistance by a factor of 1.16–1.23,and all cells from each group reach their rated lifetime of 500 cycles without reaching their end-of-life capacity.However,the cells with vibration and nail puncture experience an increase in internal resistance by a factor of 6.83–22.1,and each cell reaches its end-of-life capacity within 50 cycles.Overall,the results show that testing multiple abuse conditions simultaneously provides a better representation of the extreme limitations of cell operation and should be considered for inclusion in reference test standards.

A Comprehensive Economic Assessment of Producing Biodiesel Derived from Used Cooking Oil Using the BioPro380 EX

The authors performed economic assessment of producing biodiesel at pilot scale using used cooking oil as feed-oil in a Bio-Pro 380 EX biodiesel reactor. The overall results suggest that the biodiesel production using used cooking oil is a viable project even at large or medium scale. The payback period for producing biodiesel at a pilot scale of 31,320 liters per year was 1.5 years, which was 1 month longer than the payback period for a large plant capacity of 66,000 liters per year. The study demonstrated that the unit selling price and unit production cost are sensitive to the economic feasibility of biodiesel production, since price variations of BWP 1 result in at least a 13% increase and 12% decrease in profit, respectively. The study further revealed that feed-oil (used cooking oil) was the most expensive among all the inputs accounting for 61%, followed by methanol and direct labour with 19% and 13% respectively. The overall energy recorded to produce approximately 360 liters of biodiesel contributed to 2% only, suggesting that Bio-Pro 380 EX biodiesel reactor is relatively a low energy intensity processor. The situation is suitable for the promotion of biodiesel particularly in countries where initiatives to stimulate the development of biofuels are at its infant stage Botswana included.

Research and Analysis of Production and New Capacity of China's Electronic Copper Foil Enterprises in 2017

In the light of current fast development of new and expanded copper foil projects of electronic copper foil enterprises and recent adjustment of the main copper foil categories set to be developed by some companies(generally from lithium foil to PCB foil).The secretariat of China Electronics Materials Industry Association e-copper foil branch conducted in March,2017 an extensive and in-depth

TWO COUNTERMEASURE STRATEGIES TO MITIGATE RANDOM DISRUPTIONS IN CAPACITATED SYSTEMS

We examine a capacitated system exposed to random stepwise capacity disruptions with exponentially distributed interarrival times and tmiformly distributed magnitudes. We explore two countermeasure policies for a risk-neutral decision maker who seeks to maximize the long-nm average reward. A one-phase policy considers implementation of countermeasures throughout the entirety of a disruption cycle. The results of this analysis form a basis for a two-phase model which implements countermeasures during only a fraction of a disruption cycle. We present an extensive numerical analysis as well as a sensitivity study on the fluctuations of some system parameter values.