Switching to Perennial Energy Crops under Uncertainty and Costly Reversibility

We study a farmer’s decision to convert traditional crop land into growing dedicated energy crops, taking in account sunk conversion costs, uncertainties in traditional and energy crop returns, and learning. The optimal decision rules differ significantly from the expected net present value rule, which ignores learning, and from real option models that allow only one way conversions into energy crops. These models also predict drastically different patterns of land conversions into and out of energy crops over time. Using corn-soybean rotations and switchgrass as examples, we show that the model predictions are sensitive to assumptions about stochastic processes of the returns. Government policies might have unintended consequences: subsidizing conversion costs into switchgrass reduces proportions of land in switchgrass in the long run.real options, irreversibility, sunk costs, land conversion, biofuel, cellulosic biomass, dynamic modeling, stochastic process, biofuel policy, Land Economics/Use, Resource /Energy Economics and Policy, Risk and Uncertainty, Q42, Q24,

Alternative Land Use Policies: Real Options with Costly Reversibility

This paper adopts a real options framework to evaluate the cost-effectiveness of four types of subsidies that aim to encourage a socially desirable land use under return uncertainties and costly reversibility of land use change. We first present a land conversion model to show how the subsidies that are expected net present value (ENPV) equivalent can change a representative farmer’s optimal land conversion rules differently for converting land into an alternative use as well as converting out of it. This is because these subsidies affect the land conversion costs, land return level and uncertainty differently. Then in the context of encouraging energy crop production, we compare the probabilities of inducing the representative farmer to convert land from a current crop to an energy crop across four subsidies for the same, fixed 30-year expected government budget. Results of Monte Carlo simulations show that the insurance subsidy results in the highest probability of land being converted to the energy crop, followed by the constant subsidy. Although the cost-sharing subsidy and the variable subsidy encourage land conversion to the energy crop, they also reduce the incentive to retain land in it. Over time, these two subsidies have little effect on the probability of land converting into energy crops compared to the no-subsidy baseline. Combining the establishment cost-sharing subsidy with other annual subsidies has no added effect over single subsidies in inducing land conversion to the energy crop.Monte Carlo simulations, real options, agricultural subsidies, cost-effectiveness, two-way land conversion, Agricultural and Food Policy, Resource /Energy Economics and Policy, Q24, Q48,

Measuring the phonon-assisted spectral function by using a non-quilibrium three-terminal single-molecular device

The electron transport through a three-terminal single-molecular transistor (SMT) is theoretically studied. We find that the differential conductance of the third and weakly coupled terminal versus its voltage matches well with the spectral function versus the energy when certain conditions are met. Particularly, this excellent matching is maintained even for complicated structure of the phonon-assisted side peaks. Thus, this device offers an experimental approach to explore the shape of the phonon-assisted spectral function in detail. In addition we discuss the conditions of a perfect matching. The results show that at low temperatures the matching survives regardless of the bias and the energy levels of the SMT. However, at high temperatures, the matching is destroyed.Comment: 9 pages, 5 figure

Mid-IR Multiwavelength Difference Frequency Generation Based on Fiber Lasers

A mid-IR multiwavelength difference frequency generation (DFG) laser source with fiber laser fundamental lights is demonstrated by using the dispersion property of PPLN to broaden the quasi-phase-matching (QPM) acceptance bandwidth (BW). Our results show that the QPM BW for the pump YDFL is much larger than that for the signal EDFL. Using a multiwavelength YDFL and a single-wavelength EDFL as the pump and the signal lights, the DFG laser source can simultaneously emit 14 mid-IR wavelengths with the spacing of 14nm at a fixed PPLN temperature. Moreover, mid-IR multiwavelength lasing lines can be synchronously tuned between 3.28 and 3.47μm

Carbon Sequestration in Agriculture: Value and Implementation

Examining the value of carbon sequestration in a dynamic model, the authors demonstrate that unless the sequestration is permanent, it is only a fraction of the value of emission abatement. The magnitude of the fraction increases in the duration of sequestration, the natural decay rate of carbon, and the discount rate. The authors also show that sinks should be used as early as possible in order to optimally reduce the carbon stock. Finally, the authors propose and assess three mechanisms for efficiently introducing sequestration into a carbon permit trading market: a pay-as-you-go system, a variable-length-contract system, and a carbon-annuity-account system. All are efficient, but all may not be equally feasible to implement

A Multilayer Feed Forward Small-World Neural Network Controller and Its Application on Electrohydraulic Actuation System

Being difficult to attain the precise mathematical models, traditional control methods such as proportional integral (PI) and proportional integral differentiation (PID) cannot meet the demands for real time and robustness when applied in some nonlinear systems. The neural network controller is a good replacement to overcome these shortcomings. However, the performance of neural network controller is directly determined by neural network model. In this paper, a new neural network model is constructed with a structure topology between the regular and random connection modes based on complex network, which simulates the brain neural network as far as possible, to design a better neural network controller. Then, a new controller is designed under small-world neural network model and is investigated in both linear and nonlinear systems control. The simulation results show that the new controller basing on small-world network model can improve the control precision by 30% in the case of system with random disturbance. Besides the good performance of the new controller in tracking square wave signals, which is demonstrated by the experiment results of direct drive electro-hydraulic actuation position control system, it works well on anti-interference performance

Development of Level-of-Service Criteria based on a Single Measure for BRT in China

Bus rapid transit (BRT) has gained popularity as a cost-effective way of expanding public transit services, and its level of service (LOS) is receiving increasing attention. However, relatively little is known about the precise criteria that can consistently and objectively classify the LOS of BRT into different levels. This paper introduces the measure of “unit delay” to develop BRT LOS criteria, defined as the sum of delays a bus experiences at stops and intersections and on a 100m link. Based on field surveys conducted on BRT in Changzhou, China, we obtained a unit delay data set and established BRT LOS criteria using Fuzzy C-means Clustering. The LOS criteria can be applied for operational, design, and planning analyses for BRT systems. A method to examine the operational conditions in spatial and temporal dimensions and pinpoint the service bottlenecks of a BRT system is presented