Is Nonfarm Diversification a Way Out of Poverty for Rural Households? Evidence from Vietnam in 1993-2006

school. Using the four high quality household living standards surveys available to date this paper reveals that Vietnam’s rural labour force has been markedly diversifying toward nonfarm activities in the doi moi (renovation) reform period. The employment share of the rural nonfarm sector has increased from 23 percent to 58 percent between the years 1993 and 2006. At the individual level, the results indicate that participation in the rural nonfarm sector is determined by a set of individual-, household-, and community-level characteristics. Gender, ethnicity, and education are reported as main individual-level drivers of nonfarm diversification. Lands as most important physical assets of rural households are found to be negative to nonfarm employment. It is also evident that both physical and institutional infrastructure exert important influences on individual participation in the nonfarm sector. At the household level, a combination of parametric and semi-parametric analysis is adopted to examine whether nonfarm diversification is a poverty exit path for rural households. This paper demonstrates a positive effect of nonfarm diversification on household welfare and this effect is robust to different estimation techniques, measures of nonfarm diversification, and the usage of equivalent scales. However, the poor is reported to benefit less than the non-poor from nonfarm activities. Though promoting a buoyant nonfarm sector is crucial for rural development and poverty reduction, it needs to be associated with enhancing access to nonfarm opportunities for the poor.Rural nonfarm sector, nonfarm diversification, household welfare, Vietnam

Space Vector Modulation for Induction Motor on ARM-based Microcontroller

This article presents the review and the implementation of Space Vector Modulation (SVM) in a low-cost microcontroller-based motor drive system. The output three-phase voltages are obtained from a reference voltage vector in the polar coordinate system using the PWM technique; these voltages can reach up to the level of the DC voltage source (experimentally 16 VDC or practically 237 V with an inverter module). The article also provides a detailed presentation of the pre-calculations and the computations required for SVM on a STM32F1 ARM-based microcontroller. For achieving high frequency precision, a novel method for vector rotation based on the fixed-point arithmetic is proposed and tested. The experimental results highlight that the presented implementation including vector rotation can reach 1 Hz without significant error and it requires only 0.684 MIPS at 5 kHz computation rate for a 72 MIPS 32-bit microcontroller with single-cycle multiplication. The maximum instantaneous output phase-to-phase voltages could be as high as the DC voltage source

Performance of free-space QKD systems using SIM/BPSK and dual-threshold/direct-detection

This paper proposes a novel free-space quantum key distribution (QKD) system using subcarrier intensity-modulation (SIM) binary phase-shift-keying (BPSK) and dual-threshold/direct-detection (DT/DD) receiver with an avalanche photodiode (APD). The proposed system enables the adoption of well-developed analytical models in conventional free-space optical (FSO) communications and achieves the QKD function with a simple configuration. We analytically investigate the design criteria for transmitter and receiver, in particular, the modulation depth and the setting for dual-threshold in the context of security requirement of QKD systems. The quantum bit error rate (QBER) and the ergodic secret-key rate of the proposed system are analytically derived in closed-form expressions, considering the channel loss, atmospheric turbulence modeled by the log-normal distribution, and receiver noises. Monte-Carlo (M-C) simulations are also implemented to validate the analytical results, and numerical results confirm the feasibility of the proposed system

Port-Hamiltonian model and load balancing for DC-microgrid lift systems

This paper considers the problem of modeling a multi-source lift system where power balancing-realized through a power DC bus-should be optimally controlled. The system includes the mechanical part, a Salient Permanent Magnet Synchronous Machine (SPMSM), a battery energy storage unit, a super-capacitor, a solar panel (PV) generation unit as well as the corresponding converters to DC-links. This microgrid is connected to a three-phase utility (external) grid. A port-Hamiltonian model is proposed for the system. It includes the descriptions of nonlinear characteristics and the limitations for each components as well as some typical operation demands. Then, different optimization objectives are formulated in view of an efficient energy management within the microgrid system

COLOR AND COD REMOVAL OF DYEING WASTEWATER BY COMBINATION TREATMENT OF COAGULATION AND FENTON OXIDATION

Joint Research on Environmental Science and Technology for the Eart

Crossover from First to Second-Order Transition in Frustrated Ising Antiferromagnetic Films

In the bulk state, the Ising FCC antiferromagnet is fully frustrated and is known to have a very strong first-order transition. In this paper, we study the nature of this phase transition in the case of a thin film, as a function of the film thickness. Using Monte Carlo (MC) simulations, we show that the transition remains first order down to a thickness of four FCC cells. It becomes clearly second order at a thickness of two FCC cells, i.e. four atomic layers. It is also interesting to note that the presence of the surface reduces the ground state (GS) degeneracy found in the bulk. For the two-cell thickness, the surface magnetization is larger than the interior one. It undergoes a second-order phase transition at a temperature $T_C$ while interior spins become disordered at a lower temperature $T_D$. This loss of order is characterized by a peak of the interior spins susceptibility and a peak of the specific heat which do not depend on the lattice size suggesting that either it is not a real transition or it is a Kosterlitz-Thouless nature. The surface transition, on the other hand, is shown to be of second order with critical exponents deviated from those of pure 2D Ising universality class. We also show results obtained from the Green's function method. Discussion is given.Comment: 20 pages, 14 figure