Effects of Biochar Addition on Rill Flow Resistance

The development of rills on a hillslope whose soil is amended by biochar remains a topic to be developed. A theoretical rill flow resistance equation, obtained by the integration of a power velocity distribution, was assessed using available measurements at plot scale with a biochar added soil. The biochar was incorporated and mixed with the arable soil using a biochar content BC of 6 and 12 kg m−2. The developed analysis demonstrated that an accurate estimate of the velocity profile parameter Гv can be obtained by the proposed power equation using an exponent e of the Reynolds number which decreases for increasing BC values. This result pointed out that the increase of biochar content dumps flow turbulence. The agreement between the measured friction factor values and those calculated by the proposed flow resistance equation, with Гv values estimated by the power equation calibrated on the available measurements, is characterized by errors which are always less than or equal to ±10% and less than or equal to ±3% for 75.0% of cases. In conclusion, the available measurements and the developed analysis allowed for (i) the calibration of the relationship between Гv, the bed slope, the flow Froude number, and the Reynolds number, (ii) the assessment of the influence of biochar content on flow resistance and, (iii) stating that the theoretical flow resistance equation gives an accurate estimate of the Darcy–Weisbach friction factor for rill flows on biochar added soils.

Short communication: Analytical models for 2D landscape evolution

Numerical modelling offers a unique approach to understand how tectonics, climate and surface processes govern landscape dynamics. However, the efficiency and accuracy of current landscape evolution models remain a certain limitation. Here, I develop a new modelling strategy that relies on the use of 1D analytical solutions to the linear stream power equation to compute the dynamics of landscapes in 2D. This strategy uses the 1D ordering, by a directed acyclic graph, of model nodes based on their location along the water flow path to propagate topographic changes in 2D. This analytical model can be used to compute in a single time step, with an iterative procedure, the steady-state topography of landscapes subjected to river, colluvial and hillslope erosion. This model can also be adapted to compute the dynamic evolution of landscapes under either heterogeneous or time-variable uplift rate. This new model leads to slope–area relationships exactly consistent with predictions and to the exact preservation of knickpoint shape throughout their migration. Moreover, the absence of numerical diffusion or of an upper bound for the time step offers significant advantages compared to numerical models. The main drawback of this novel approach is that it does not guarantee the time continuity of the topography through successive time steps, despite practically having little impact on model behaviour.

Simple, Accurate Calculation of Mechanical Power in Pressure Controlled Ventilation (PCV)

Power is a promising new metric to assess energy transfer from a ventilator to a patient, as it combines the effects of multiple different parameters into a single comprehensive value. For volume-controlled ventilation (VCV), excellent equations exist for calculating power from basic ventilator parameters, but for pressure-controlled ventilation (PCV), an accurate, easy-to-use equation has been elusive. Here, we present a new power equation and evaluate its accuracy compared to the three published PCV power equations. When applied to a sample of 50 patients on PCV with a non-zero rise time, we found that our equation estimated power within an average of 8.4% ± 5.9% (mean ± standard deviation) of the reference value. This new equation is accurate and simple to use, making it an attractive option to estimate power in PCV cases at the bedside.

RASING FORCES: PATTERNS OF REDISTRIBUTION OF POWER IN WORLD POLITICS

This article examines Rising Powers: Patterns of Power Redistribution in Global Politics, by creating a reliable framework for understanding the increasing complexities of the actors in the international arena. This is by studying the concept of power, which is one of the basic concepts in political science, whereby force imposes its logic on the curves of international relations and has multiple forms due to its complex nature. In what can be considered dual roles and reciprocal interactions, and to understand the dimensions, manifestations and nature of the actors in the power equation, especially the emergence of tensions and conflicts between the interests of the United States of America and the emerging powers in the world in light of the new strategic directions after the Cold War and each party's attempt to dominate areas of influence and wealth Proceeding from a pragmatic geopolitical policy.

Short communication: Analytical models for 2D landscape evolution

Numerical modelling offers a unique approach to understand how tectonics, climate and surface processes govern landscape dynamics. However, the efficiency and accuracy of current landscape evolution models remain a certain limitation. Here, I develop a new modelling strategy that relies on the use of 1D analytical solutions to the linear stream power equation to compute in 2D the dynamics of landscapes. This strategy uses the 1D ordering, by a directed acyclic graph, of model nodes based on their location along the water flow path to propagate topographic changes in 2D. I demonstrate that this analytical model can be used to compute in a single time step, with an iterative procedure, the steady-state topography of landscapes subjected to river, colluvial and hillslope erosion. This model can also be adapted to compute the dynamic evolution of landscapes under either heterogeneous or time-variable uplift rate. This new model leads to slope-area relationships exactly consistent with predictions and to the exact preservation of knickpoint shape throughout their migration. Moreover, the absence of numerical diffusion or of an upper bound for the time step offer significant advantages compared to numerical models. The main drawback of this novel approach is that it does not guarantee the time-continuity of the topography through successive time steps, despite practically having little impact on model behaviour.

Newly Discovered Śaiva-Ascetic Icons from West Bengal

Koṭivarṣa, a sacred place and an administrative unit that is mentioned in early medieval Indian religious and epigraphic sources from 700 to 1200 ce, is the area of focus of this essay. As an administrative unit, it was almost coterminous with the old Dinajpur district of Bengal, which is now divided into the present Indian state of West Bengal and Bangladesh. At one point in time, its headquarters came to be known as Devīkoṭa, underscoring its rise as a prime place for Devī, the Mother goddess. Sculptural arrays of the Mother goddess from this place point to the domineering presence of her fearsome principles; they parallel textual descriptions about the sacred importance of a wrathful form of the Mother, normally referred to as Cāmuṇḍā. The religious texts, however, do not speak of the ascetics who might have performed the rituals to propitiate the Mother. We do not yet know if any new dimension was added to the corpus of rituals, and the Śiva-Śakti power equation after the Saiddhāntika Śaiva preceptors affiliated with Golagī great monastery of Durvāsas lineage entered Devīkoṭa at the end of the tenth century. This essay searches for answers in the visual elements on the lower registers of stone steles, such as the devotees/donors, other individuals in the service of the Mother Goddess, potfuls of offerings, and the environment of cremation grounds in which worship took place. The main deity and associated figures occupying the larger space in the middle of the steles have tantric content. Icons of Śaiva ascetics from West Bengal, including the three newly discovered examples, are important subjects for this essay, which concludes with the transformation of Devīkoṭa to Bangarh, where Śiva emerged as the chief god par excellence. The Devī had lost her koṭa, her bastion, forever.

Transient Stability Analysis of Grid-Connected Converter Driven by Imbalance Power under Non-Severe Remote Voltage Sag

In the transient process of the grid-connected converter (GCC), the existing research mainly focuses on the impact of the control loops. Little attention is paid to the transient stability issues driven by the imbalance between the input power and output power of GCC. This paper shows that the transient stability issues will still exist even if ignoring the dynamics of phase-locked loop (PLL) and current loop. In this paper, the models of the AC grid and the GCC are built under the assumption that the dynamics of the PLL and current loop are ignored. Then, by analyzing the transient process of GCC under non-severe remote voltage sag, the effects of the imbalance power on the transient stability of GCC are discussed. Moreover, for the GCC to operate stably after the transient process, there should be a maximum input power limit (MIPL) for GCC, and the imbalance power equation is applied in this paper to determine the transient stability of GCC. Furthermore, the effects of the current limitation on the transient stability of the GCC are also discussed. Finally, the theoretical analysis has been verified by means of simulations.

EMG Based Gesture Recognition Using the Unbiased Difference Power

In this paper, we propose an unbiased difference power that is robust against noise as a feature for electromyography (EMG)-based gesture recognition. The proposed unbiased difference power is obtained by subtracting the noise-biased part from the difference power. We derive the difference power equation and discover that the difference power is biased by twice the noise power. For noise power estimation, we utilized the characteristics of the EMG signal and estimated the noise power from the resting period. For performance evaluation, we used EMG signals provided by the open source Ninapro project database. We used the recognition accuracy as an evaluation index. We compare the recognition accuracy of the case using the proposed unbiased feature with those of two conventional cases. Experimental results show that the proposed unbiased difference power improves the accuracy compared with conventional ones. As the noise level increases, cases where the proposed unbiased difference power is used show a clear improvement in accuracy compared with the two conventional cases. For the signal-to-noise ratio (SNR) of 0 dB, the proposed unbiased difference power improves the average accuracy by more than 12%.

Critical Nitrogen and Nutritive Index in Cultivars of Cenchrus purpureus (Schumach) Morrone

Objective: To determine and compare the parameters of the nitrogen curve and the nutritive nitrogen index of cultivars of Cenchrus purpureus with and without nitrogenous fertilization.Design/Methodology/Approach: Five cultivars of C. purpureus with or without fertilization were evaluated, and the dose was 141N-43P-20K. The grass was harvested every 21 d with production of dry matter (DM) and nitrogen (N). Growth rates and Critical Nitrogen (Nc) were obtained. The negative power equation with its parameters Nc and the Nitrogen Decrease Coefficient (Cd) were used. The Nutritive Nitrogen Index (NNI) was obtained with the Nc parameter of each curve, divided by the N content of the cultivar in each sampling. The data were analyzed with a completely randomized design in a factorial arrangement of five (cultivars) and two levels of fertilization. Results: Nc of 2.6 and a Cd of 0.65 fertilized, and 1.14 of Nc and 0.68 of Cd without fertilization, and in turn all of them supplemented the amount of N for their growth from soil. The NNI was 0.8 for the fertilized cultivars, with classification of excess and sufficient for the first 56 d. Study Limitations/Implications: Variables to determine the availability of water and the balance of soil-plant N could further expand the knowledge of these tools. Findings/Conclusions: Parameters obtained such as Nc and NNI help to determine nutritional status of the fodders.