Physiological Efficiency of some Weeds Species under Hill Farming Systems of Subtropical Meghalaya

Weeds are integral part of any farming system. Weeds are more aggressive in their ability to utilize limited moisture and nutrients in the soil relative to cultivated crops. Weeds grow more profusely in high rainfall areas such as subtropical Meghalaya owing to favourable climatic conditions which favours the growth of weeds particularly in uplands and limits the crop yields due to increased crop-weed competition for nutrients and light. The weed species such as Ageratum conyzoides, Spilanthus acmella, Galinsoga parviflora, Bidens pilosa, Crassocephalum crepidioides, Polygonum capitatum, Alternanthera philoxeroides, Amaranthus spinosus and Mikania micrantha are very common in most of the cultivated crops. These weeds are also very common in grazing lands, wastelands, agroforestry systems, abandoned fields etc. in northeast India and some of them are also consumed as green vegetables by the local inhabitants. Most of these weeds are also a menace in fodder cultivation and managing grasslands. A high rate of photosynthesis is always associated with higher productivity, unless sink capacity is limiting. However, studies on photosynthesis and its associated parameters in relation to crop-weed competition are limited. Therefore, an attempt was made to study the photosynthesis rate, transpiration rate, stomatal conductance and other associated parameters in major crops and the associated weed species under hill environment

Controlled power flow capacitive divider for electric power tapping

Abstract: Capacitive divider systems for tapping electric power from high voltage transmission lines are known to exhibit certain detrimental problems of stability, sub-resonance harmonic oscillations, and ferroresonance when coupled with non-linear loads. On the other hand, they can improve reactive power flow, power factor and contribute to improved harmonic filtration of the larger power system. This paper, therefore, proposes a controlled power flow conditioner as an essential integral component of a capacitive divider system to control power transfer between the high voltage transmission line, capacitive divider system, and the load. The ultimate objective of this conditioner is to mitigate or minimize the attendant problems associated with coupling the system to the load, and optimize the derivable benefits to the larger network

A PWM Strategies for diode assisted NPC-MLI to obtain maximum voltage gain for EV Application

Abstract: The projected diode assisted Neutral Point Diode Clamed (NPC-MLI) with the photovoltaic system produces a maximum voltage gain that is comparatively higher than those of other boost conversion techniques. This paper mainly explores vector selection approach pulse-width modulation (PWM) strategies for diode-assisted NPC-MLI to obtain a maximum voltage gain without compromising in waveform quality. To obtain a high voltage gain maximum utilization of dc-link voltage and stress on the power switches must be reduced. From the above issues in the diode assisted NPC-MLI leads to vector selection approach PWM technique to perform capacitive charging in parallel and discharging in series to obtain maximum voltage gain. The operation principle and the relationship of voltage gain versus voltage boost duty ratio and switching device voltage stress versus voltage gain are theoretically investigated in detail. Owing to better performance, diode-assisted NPC-MLI is more promising and competitive topology for wide range DC/AC power conversion in a renewable anergy application. Furthermore, theoretically investigated are validated via simulation and experimental results

Hybrid Multicarrier Random Space Vector PWM for the Mitigation the Acoustic Noise

The pulse width modulation (PWM) inverter is obvious for any industrial and power sector application. Particularly industrial drives are very keen on the industrial standards. Many modulations approached such a drives objects of DC-link consumption, harmonics suppression in lower and higher order spectrum and noise reduction. The still random PWM is a best candidate for reducing the noises on the PWM operated AC drives. There are various Random PWM (RPWM) methods has been developed and investigated for the PWM inverter fed drive noise reductions, still the shortcomings are existence on these method items of their less randomness and complex digital circuitry. These PWM dealt the spreading harmonics there by decreasing harmonic effects on the system. However, these techniques overlook the effect of acoustic noise and DC -link utilizations Therefore, in this paper mainly deals with to combined RPWM principle in space vector PWM (SVPWM) to generate random PWM generation using asymmetric frequency multi carrier called multicarrier random space vector PWM (MCRSVPWM). The SVM agreements with multicarrier (different fixed frequencies as carrier waves) which are chosen with the aid of a random binary bit generator. The proposed RSVM generated pulses with a randomized triangular carrier (4 ± 1.5 kHz), while the conventional RPWM method contains of the random pulse position with a fixed frequency triangular carrier. The simulation study is performed through MATLAB/Simulink for 3 HP asynchronous induction motor drive. The Experimental validation of proposed MCRSVPWM is tested with 2kW six switch (Power MOSFET – SCH2080KE) inverter power module fed induction motor drive.publishedVersio

Soil health as affected by altered land configuration and conservation tillage in a groundnut (Arachis hypogaea) - toria (Brassica campestris var toria) cropping system

A field experiment was conducted during the year 2009-11 at ICAR Research Complex for North Eastern Hill Region (NEHR), Meghalaya to study the influence of land configuration and conservation tillage on soil health in a groundnut-toria cropping system. The experiment consisted of seven treatments [i. flat bed farmer’s practice (FP) no residue; ii. broad beds and furrows (BBF) with residue incorporation; iii. BBF with residue + hedge leaves (Tephrosia sp) incorporation; iv. BBF with residue + hedge leaves (no tillage, NT); v. raised bed (RB) with residue incorporation; vi. RB with residue + hedge leaves incorporation; vii. RB with residue + hedge leaves (NT)] laid out in randomised block design and replicated thrice. The conservation treatments were found to significantly improve biological activity and chemical properties of soil. However, physical properties such as texture and bulk density were not significantly affected by any of the treatments. Infiltration rate and hydraulic conductivity were 108% and 46% higher, respectively, in the treatments under RB with residue + hedge leaves (NT) as compared to FP. Soil microbial biomass carbon was 67% higher under RB with residue + hedge leaves incorporation than FP after the harvest of both the crops in the second year while dehydrogenase activity was 135% higher in RB with residue + hedge leaves (NT) after the harvest of groundnut and RB with residue incorporation after the harvest of toria than FP, respectively. System productivity under RBs were significantly higher than that recorded under BBF and FB. Conservation treatments showed better soil health at the end of the cropping cycles and it is concluded that raised beds along with residue management can provide an alternative and sustainable technology contributing to sustainable agriculture in the NEHR of India which can be extrapolated to other similar areas

Neutral Point Clamped Transformerless Multilevel Converter for Grid-Connected Photovoltaic System

Transformer-less (TL) inverter topologies have elicited further special treatment in photo-voltaic (PV) power system as they provide high efficiency and low cost. Neutral point clamped (NPC) multilevel-inverter (MLI) topologies-based transformer-less are being immensely used in grid-connected medium-voltage high-power claims. Unfortunately, these topologies such as NPC-MLI, full-bridge inverter with DC bypass (FB-DCBP) suffer from the shoot-through problem on the bridge legs, which affect the reliability of the implementation. Based on the previous above credits, a T type neutral point clamped (TNP) - MLI (TNP-MLI) with Transformer-less topology called TL-TNP-MLI is presented to be an alternate which can be suitable in the grid connected PV power generation systems. The suggested TL-TNP-MLI topologies free from inverter bridge legs shoot-through burden, switching frequency common-mode current (CMC), and leakage current. The control system of the grid interface with hysteresis current control (HCC) strategy is proposed. The effectiveness of the proposed PV connected transformer-less TNP-MLI topology with different grid and PV scenario has been verified through the MATLAB/Simulink simulation model and field-programmable gate area (FPGA) based experimental results for a 1.5 kW system.publishedVersio

Video synthesis from Intensity and Event Frames

Event cameras, neuromorphic devices that naturally respond to brightness changes, have multiple advantages with respect to traditional cameras. However, the difficulty of applying traditional computer vision algorithms on event data limits their usability. Therefore, in this paper we investigate the use of a deep learning-based architecture that combines an initial grayscale frame and a series of event data to estimate the following intensity frames. In particular, a fully-convolutional encoder-decoder network is employed and evaluated for the frame synthesis task on an automotive event-based dataset. Performance obtained with pixel-wise metrics confirms the quality of the images synthesized by the proposed architecture

Weedy rice: problems and its management

ABSTRACT Weedy rice belongs to the same genus and species as cultivated rice but with different forms. It appears as hybrid swarms due to introgression of genes between wild and cultivated species in nature. In Asian rice, it is known as Oryza sativa var. spontanea whereas in African context it is said as O. sativa var. stapfii. It grows faster; produces more tillers, panicles and biomass; makes better use of available N; shatters earlier; has better resistance to adverse conditions; and possesses longer dormancy in soil. Because of its high competitive ability, it becomes a serious threat to rice growers worldwide. Great morphological variability, similar growth behavior and high biological affinity with cultivated varieties make its control difficult. No single management technique can effectively control weedy rice. An appropriate combination of preventive, cultural, mechanical and chemical control measures is essential

X-ray and ion emission studies from subnanosecond laser-irradiated SiO2 aerogel foam targets

In this experiment, a comparative study of ion and X-ray emission from both a SiO2 aerogel foam and a quartz target is performed. The experiment is performed using Nd:glass laser system operated at laser energy up to 15 J with a pulse duration of 500 ps with focusable intensity of 1013–1014 W/cm2 on target. X-ray fluxes in different spectral ranges (soft and hard) are measured by using X-ray diodes covered with Al filters of thickness 5 µm (0.9–1.56 keV) and 20 µm (3.4–16 keV). A 2.5 times enhancement in soft X-ray flux (0.9–1.56 keV) and a decrease of 1.8 times in hard X rays (3.4–16 keV) for 50 mg/cc SiO2 aerogel foam is observed compared with the solid quartz. A decrease in the flux of the K-shell line emission spectrum of soft X rays is noticed in the case of the foam targets. The high-resolution K-shell spectra (He-like) of Si ions in both the cases are analyzed for the determination of plasma parameters by comparing with FLYCHK simulations. The estimated plasma temperature and density are T c = 180 eV, n e = 7 × 1020 cm−3 and T c = 190 eV, n e = 4 × 1020 cm−3 for quartz and SiO2 aerogel foam, respectively. To measure the evolution of the plasma moving away from the targets, four identical ion collectors are placed at different angles (22.5, 30, 45, and 67.5°) from target normal. The angular distribution of the thermal ions are scaled as cosnθ with respect to target normal, where n = 3.8 and 4.8 for the foam and quartz, respectively. The experimental plasma volume measured from the ion collectors and shadowgraphy images are verified by a two-dimensional Eulerian radiative–hydrodynamic simulation (POLLUX code