A Numerical and Experimental Study on Effect of Composition of Ar-N2 Shielding Gas on the Weld Bead Profile and its Prediction for Hot Wire Arc Additive Manufacturing

Wire arc additive manufacturing is a process of making three-dimensional metal parts in a layer-by-layer approach using a feed wire and electric arc as a heat source. Wire arc additive manufacturing (WAAM) is becoming more popular due to its ability to create complex 3D parts, less build time, high deposition rate, and significant cost savings. Out of the many parameters used in WAAM, one of the important parameters is shielding gas which plays a significant role in material quality, properties, and defects. In this study, a controlled amount of Argon (Ar) and Nitrogen (N2) shielding gases are used to see the effect on the weld bead depth and width. In addition, a computational fluid dynamics (CFD) model is used to perform numerical analysis. The data collected from the experiment is used to perform a regression analysis to predict future values. The amount of shielding gas mixture is controlled through a flowmeter to three different total flowrates. The result shows there is an increase in the depth and width of the weld bead with the increase in N2 percentage in the Ar-N2 shielding gas mixture. With the increase in Nitrogen percentage, the tungsten arc is observed unstable and spattering is noticed. The temperature of the surface of the base metal is increased while using the Ar-N2 mixture. The experiment result is further verified by developing and analyzing a three-dimensional computational fluid dynamics model using a volume of fluid (VOF) method. Support vector machine (SVM) regression model with Gaussian kernel function is used to perform the predictive regression analysis. Out of all the regression models, SVM has the lowest model loss for the collected data

Extended landslide velocity and analytical drag

The landslide velocity plays a dominant role in estimating impact force and devastated area. Here, based on Pudasaini and Krautblatter (2022), I develop a novel extended landslide velocity model that includes the force induced by the hydraulic pressure gradient which was neglected by all the existing analytical landslide velocity models. By a rigorous conversion between this force and inertia, I develop two peer systems expecting to produce the same results. However, this contradicts with our conventional wisdom. This raises a question of whether we should develop some new balance equations. I compare the two velocity models that neglects and includes the force induced by the hydraulic pressure gradient. Analytical solutions produced by the two systems are different. The new model is comprehensive, elegant, and yet an extraordinary development as it reveals serendipitous circumstances resulting in a pressure-inertia-paradox. Surprisingly, the mass first moves upstream, then it winds back and accelerates downslope. The difference between the extended and simple solution widens strongly as the force associated with the hydraulic pressure gradient increases, demonstrating its importance. Viscous drag plays an important role in controlling the landslide dynamics. However, no explicit mechanical and analytical model exists for this. The careful sagacity of the graceful form of new velocity equation results in a mechanically extensive, dynamically evolving analytical model for viscous drag, the first of this kind. A dimensionless drag number is constructed. Contrary to the prevailing practices, I have proven that drags are essentially different for the expanding and contracting motions, an entirely novel perception. Drag coefficients are close to the often used empirical or numerical values. But, now, I offer an innovative, physically-founded analytical model for drag in mass flow simulation

Unified Mechanical Erosion Model for Multi-phase Mass Flows

Erosion poses a great challenge in multi-phase mass flows as it drastically changes flow behavior and deposition pattern by dramatically increasing their masses, adversely affecting population and civil structures. There exists no mechanically-explained, unified multi-phase erosion model. We constitute a novel, unified and comprehensive mechanical erosion rates for solid and fluid phases and demonstrate their richness and urgency. This is achieved by seminally introducing interacting stresses across erosion-interface. Shear resistances from the bed against shear stresses from the landslide are based on consistent physical principles. Proposed multi-phase interactive shear structures are mechanically superior and dynamically flexible. Total erosion rate is the sum of solid and fluid erosion rates which are mechanically extensive and compact. Erosion rates consistently take solid and fluid fractions from the bed and customarily supply to solid and fluid components in the flow. This overcomes severe limitations inherited by existing models. For the first time, we physically correctly construct composite, intricate erosion velocities of particle and fluid from the bed and architect the complete net momentum productions that include all interactions between solids and fluids in the landslide and bed. We invent stress correction, erosive-shear-velocity, super-erosion-drift and erosion-matrix characterizing complex erosion processes. By embedding well constrained extensive erosion velocities, unified erosion rates and net momentum productions including erosion-induced inertia into mass and momentum balances, we develop a novel, mechanically-explained, comprehensive multi-phase model for erosive mass flows. As new model covers a broad spectrum of natural processes it offers great opportunities for practitioners in solving technical, engineering problems related to erosive multi-phase mass flows

Effect of Pollination on Qualitative Characters of Rapeseed (Brassica campestris l. Var. Toria) Seed in Chitwan, Nepal

An experiment was conducted to study the effect of pollination quality of rapeseed seed in Chitwan during 2012-2013. The experiment was designed in Randomized Complete Block with four replications and five pollination treatments. The rapeseed plots were caged with mosquito nets at 10% flowering except natural pollination. Two-framed colonies of Apis mellifera L. and Apis cerana F. were introduced separately for pollination, and control plot caged without pollinators. The highest germination percent was observed on Apis cerana F. pollinated plot seeds (90.50% germination) and lowest on control plots (42.00% germination) seeds. Similarly, seed test weight of Apis cerana F. pollinated plots (3.22 gm/ 1000 seed) and Apis mellifera L. pollinated plots (2.93 gm/1000 seed) were and control plots (2.26 gm/ 1000 seed) recorded respectively. However, oil content was recorded highest on pollinated by Apis cerana F. (36.1 %) and lowest on control plots (32.8%). This study clearly indicated pollination increases the seed quality of rapeseed and therefore, management of honeybee is necessary for higher quality of rapeseed under Chitwan condition

Midline Household Survey Results: Rupandehi, Nepal

This report summarizes the main findings from the household midline survey conducted in seven villages of the district of Rupandehi, one of CCAFS site, in Nepal in July 2019. The household survey revisited the 135 households of the 2012 CCAFS baseline survey and used the same standardized household survey tools. The Open Data Kit (ODK) software was used for the data collection. The results show that the majority of households in Rupandehi produce a variety of crops, among which rice, wheat and mustard. Many farmers also rear livestock such as cows, buffalo, chicken, oxen and goat. All members of the family typically engage in the on-farm agricultural work but men are more likely to be also involved in off-farm activities. Households members derive their income from a variety of sources, the main one being payments from the government or other projects/programs. This is followed by remittances and income from businesses as the main alternative income sources for many households. Moreover, most of the farmers have made changes in their agricultural practices since the baseline. Many have introduced higher-yielding crop varieties or have stopped keeping one or more types of animals on the farm. In terms of food security, the majority of the households surveyed in Rupandehi district are food secure throughout the entire year. The households mostly obtain their food directly from their farms. However, some of the households purchase food from other sources, especially during the month of June, July and August. Most farmers are small landholders, almost 75% of the households’ land sizes are marginal (< 1 ha), followed by a minority of smallholders owning between 1 and 2 ha of land. 98% of the households indicated buying seeds and inorganic fertilizers whereas 95% of households reported the purchase of pesticides and insecticides. 70% of households also recorded the purchase of veterinary medicine. According to the survey, television, cell phone and bicycle are the most common assets in the area. Internet access is also common in many households. Women are mostly involved in crops cultivation, mainly vegetables and cereals along with rearing livestock. The farmers have shifted towards higher-yielding and better-quality varieties of rice, and wheat. The survey findings indicate that farmers are well aware of agricultural innovations and tend to use new crop varieties

Nutritional requirement and its role on honeybee: a review

Honey bees play significant role in crop pollination. As, honeybee nutrition is raising global topic in beekeeping, it’s essential nutrients, nutrient sources and&nbsp; role in honey bees are reviewed in this paper. Like other animals, honeybees also need carbohydrate, protein, vitamins, minerals and water. These nutrients are primarily supplemented by pollen, nectar, royal jelly or water. Adequate supplement of these nutrients play significant role in growth and development in honeybees and also development of immunity in honeybees. Knowledge of bee nutrition helps to manage nutrient in bee colony and prevents them from different diseases and pests

The Trouble with Trebles: What Violates G.S. 75-1.1?

At first glance the North Carolina Unfair and Deceptive Trade Practices Act appears to be a broad, almost unconstitutionally vague statute. Its federal counterpart, the Federal Trade Commission Act, evoked similar responses when it was first enforced. Like the FTC Act, North Carolina General Statute § 75-1.1 has taken shape through judicial interpretation and legislative modification. (North Carolina General Statutes hereinafter referred to as G.S.). As this process has proceeded over the last decade or so, many aspects of the scope and application of the statute have been determined. No general answer, however, has been given to the question of just what does violate the statute. The boundary between a simple breach of contract, rendering one liable for at most simple damages, and an unfair trade practice, rendering one liable for treble damages and attorney\u27s fees, remains ill-defined. The significance of the question is clear, both to the used car dealer and his customer arguing over an $800 automobile, and to the businessman whose$8,000,000 deal falls through. This problem is highlighted, but not illuminated, by the conflict of analytical processes between the Supreme Court of North Carolina and the U.S. Court of Appeals for the Fourth Circuit. This conflict is evidence of uncertainty in the objectives of the statute and uncertainty among the judiciary as to the basic desirability of the statutory remedy