Area Growth Rate Research Articles

Preparation of Adsorbents by Pyrolysis of Sludge Mixed With Steel Slag and Study on Adsorption of Chromium Ions in Water

In this study, the dewatered sludge from the sewage plant and the open-hearth steel slag of the steel plant are used as raw materials. As two wastes, they were mixed and pyrolyzed to prepare a composite absorbent. Further, the adsorption mechanism of the adsorbent to chromium ions in the sewage is explored. The pyrolysis reaction behavior of sludge mixed with steel slag was studied by the thermogravimetric analysis technology. SEM, BET, and XPS were used to analyze the specific surface area, pore size distribution, and pore structure characteristics of pyrolysis products, respectively. Moreover, a comprehensive analysis of the adsorbent was carried out for the adsorption mechanism of hexavalent chromium ions. The results show that the addition of steel slag promotes the pyrolysis of the sludge in each stage. When the content of steel slag is 80%, the increases of reaction rate are the most obvious with the largest increase of weight loss rate in each stage. The SEM results show that the enrichment of sludge on metal oxides is enhanced in the high-temperature range (600–700°C). Besides, when the content of steel slag is 40–60%, the mixture’s growth rate of the specific surface area can reach 600% and the growth rate of total pore volume can reach 350% (the situations of sludge as the baseline). Regarding the measurement of Cr(VI), the adsorption rate of the steel-slag solution is 50.93% and that of the sludge solution is 69%. However, the adsorption rate can be increased to 95% when the steel slag and sludge were mixed as an adsorption solution. In conclusion, the adsorption mechanism of Cr(VI) by additives is controlled by both physical and chemical processes. The present study provides a theoretical basis and technical support for the scientific and reasonable utilization of sludge and steel slag.

Is Organic Rice bean (Vigna umbellata) Farmers Economically better Off? AnEmpirical Analysis

The study was conducted in North Eastern Hill (NEH) region of India during 2018-2020.Multistage sampling technique was adopted. Sikkim was selected purposively as the controlstate and Nagaland was selected based on the highest area and production under pulses. 60respondents each from organic adopter and non-adopter were selected making a total samplesize of 120. The growth rate in area, production and productivity at the world, India andNEH states were found to be positive. However, higher growth rate were observed forthe NEH region. Significance difference was observed only on cost of fertilizers. The totalcost of rice bean cultivation was lower in organic adopter by 1.71 per cent. The averageyield was significantly higher for the organic adopter. The gross income and net incomewere also higher for the organic adopter. Organic farming was found to be more profitableand it can enhance the farmer’s income. Allocative efficiency indicates that all the resourcesused in the region need to be increase so as to achieve the maximum potential yield andhenceforth increase the returns.

Influência de Trichoderma harzianum e Bacillus thuringiensis na redução das taxas de NPK no crescimento, fisiologia e qualidade de frutos de Citrus aurantifolia

Continuous use of chemical fertilizers gradually shrinks the crop yield and quality, and these adverse effects can be reduced by adopting new sustainable practices such as the use of manure, biofertilizers, and nano fertilizers. Limited information is existed on the application of Trichoderma harzianum and Bacillus thuringiensis microbes to improve lemon seedlings growth, physiology, and fruit formation. Therefore, the current study is aimed to evaluate the effects of T. harzianum and B. thuringiensis microbes mixing with low levels of inorganic fertilizer (NPK) on the plant growth, development, and quality of limau nipis (key lemon) fruits. The lemon seedlings growing media were inoculated during transplanting with T. harzianum and B. thuringiensis at various NPK fertilizers under polybagged conditions. The seedlings were grown around eighteen (18) months after inoculation with biofertilizers followed by Randomized Complete Block Design (RCBD) with five (5) replications. The results showed that T. harzianum with 50 g of NPK treatment (T2) increased the seedling's height, branch number, leaf height, ground area, and absolute growth rate (AGR) plant height by 50.12%, 107.84%, 17.91%, 17.91%, 116.93%, and 56.02%, respectively, over the control treatment. The number of leaves (60.82%), leaf area (42.75%), stem diameter (27.34%), specific leaf area (SLA) (39.07%), leaf area index (LAI) (54.40%), and absolute growth rate for leaf number (73.86%), leaf area (306.85%) and stem diameter (46.8%) of lemon seedlings increased significantly with B. thuringiensis plus 50 g NPK treatment (T3). The applications of B. thuringiensis with 25 g NPK fertilizer treatment (T5) increased leaf fresh weight (LFW), leaf dry weight (LDW), leaf moisture content (LMC), specific leaf weight (SLW), leaf relative growth rate (RGR), and chlorophyll content by 96.45%, 56.78%, 13.60%, 24.76%, 45.45%, and 16.22%, respectively, over the control group. In addition, T5 treatment increased the fruits number, individual fruit weight, fruit diameter, fruit dimension, leaf total soluble solids (TSS), and fruit TSS content of lemon tress by 81.81%, 55.52%, 43.54%, 25.69%, 89.47%, and 70.78% compared to the control treatment. Furthermore, soil inoculation of B. thuringiensis significantly increased the pulp to peel ratio and juice content of lemon fruits. From this study, it can be concluded that soil inoculation of both T. harzianum and B. thuringiensis with 25-50% NPK during transplanting improved plant growth, physiology, and fruit quality of limau nipis trees.

The potential of Central Java local black rice and red rice as drought tolerant cultivars

Black and red rice contain nutritional values not found in white rice. They contain anthocyanins which are beneficial to health. Drought stress can potentially reduce rice yield. So, it is necessary to develop local black and red rice into tolerant cultivars. This study used a completely randomized design (CRD) with cultivar factor (V) and drought stress level (K). Drought stress treatment was carried out when the plants were 35-95 DAP (days after planting) using the modified gravimetric method. Plant destruction was conducted at 7 and 21 DAT (days after treatment) to measure the growth analysis component. The observation of the growth analyses was plant dry weight, leaf area (LA), specific leaf area (SLA), relative growth rate (RGR), and net assimilation rate (NAR). Agronomic characters by observing shoot-root ratio and flowering age. The results showed drought stress decreased plant dry weight, leaf area, and relative growth rate on Sragen black rice. Jelitheng Karanganyar showed high RGR and NAR under drought stress and the fastest flowering age response. Wonogiri black rice gave the growth response by reducing specific leaf area. The highest shoot-root ratio was shown on Wonogiri black rice.

Nitrogen and weed management effects on weeds and yield of barley in Kandahar, Afghanistan

Growth and yield of barley (Hordeum vulgare L.) are highly influenced by nutrients and weed management. Nitrogen (N) is the most crucial nutrient to which barley crop responds readily. Efficient management of N and weeds can provide higher yield, better quality, and higher income to the farmers. Therefore, a field experiment was conducted in a split-plot design with three replications during winter season of 2019-20 in the Afghanistan National Agricultural Sciences and Technology University (ANASTU), Kandahar, Afghanistan to evaluate the effect of weed and N management on weeds growth and barley productivity. There were three weed management options in main plots, such as weedy check, herbicide use alone [post-emergence application (PoE) of clodinafop-propargyl 60 g/ha + metsulfuron-methyl 4 g/ha (tank-mix) at 30 days after sowing (DAS)], and integrated weed management (IWM) involving stale seed bed 15 days before sowing + wheat crop residue (2.5 t/ha) retention + clodinafop-propargyl + metsulfuron-methyl (tank-mix) PoE with half of the recommended dose at 30 DAS]. Four N levels (~0, 40, 80 and 120 kg N/ha, i.e., N0, N40, N80 and N120) were included as sub-plot treatments. The IWM led to significantly lower density and biomass of weeds at 40 and 70 DAS and significantly increased weed control efficiency (WCE) and weed control index (WCI). Clodinafop-propargyl (60 g/ ha) + metsulfuron-methyl (4 g/ha) (tank-mix) PoE also resulted in significantly lower density and biomass of weeds and higher WCE and WCI than weedy check at all stages. IWM being at par with clodinafop-propargyl + metsulfuron-methyl (tank-mix) PoE led to higher growth (crop height, dry weight, leaf area index and growth rate) and yield of barley. On the contrary, the effect of nitrogen levels was not significant on the weed density and biomass reduction. N120 and N80 were comparable with respect to growth, yield attributes and yield of barley. Thus, IWM with 80 kg N/ha may be recommended for better weed management and higher barley yield and income in Kandahar, Afghanistan.

Autonomous Cleaning System Using Manipulator for Niche Area of Ship Hull: A Preliminary Study

Biofouling is a significant eco-economical problem. Because biofouling causes ships to experience skin friction drag and disturbs the ecosystem, the regulation of ship hull cleaning is being improved. However, the niche areas of a ship are difficult to clean using a vehicle-based robot because of the complex cleaning area and fast growth rate of biofouling. In this study, we developed an autonomous cleaning system using a multi-degree-of-freedom hydraulic manipulator for the niche area of a ship hull. Our system uses a manipulator to reach a complex niche area and recognizes the cleaning target surface using an underwater laser scanner. Based on the recognized cleaning area, the robot plans an optimal path considering the full coverage and normal vectors of the target area. Our proposed robot system was verified on the ground and under water and showed adequate cleaning performance.

Performance of Cost and Prices of Soybean in Vidarbha

"In Maharashtra State, the area under soybean cultivation during 2019-20 was 4124.01 (000) hectares with total production of 4825.63 (000) tonnes. Maharashtra is the second largest soybean growing state in the country. In Vidarbha region the area under soybean cultivation during 2019-20 was 4124.01 (000) hectares with production of 4825.63 (000) tonnes. Keeping in view the importance of Soybean crop in Vidarbha the present study was conducted with an defined objectives & methodology. The study revealed that, the growth rates of Area, Production & Productivity indicates stagnant growth during the study period. The coefficient of variation of Area Production & Productivity were 8.78 %, 33.19% and 35.12% respectively. The coefficient of variation in input utilization for soybean was ranges from 3.19% to 180%. However highest for female labour i.e., 180.78% whereas the growth rates for male labour and bullock labour were declined by -1.94 and -11.42 % per annum respectively. The cost of cultivation is in increasing trend. On the other hand CGR for Cost of Production was estimated 8.25% per annum and statistically found significant. However MSP increases at the rate of 9.66 % per annum and Price received by farmer at 4.54% per annum. The share of input cost to the total cost was highest in Hired Human Labour (Male & Female) i.e., 18.68%. Followed by Machine power and Seed component 13.25% and 11.16% respectively. The average yield was receive 13.24 qtl/ha. The input output ratio at Cost A is 1.41, Cost B is 1.06 and at Cost C no profit no loss was recorded. The input out put ratio at Cost A & B was more. Which means crop is profitable at variable cost, farmers were received higher producers price than MSP. But the cost of Production was more than MSP. The parity between Cost of Production and MSP was ranges from ` 162.58 to ` 1788.12 during last ten years. The study further indicates that on an average the percentage of cost of production over previous year was 1.19% on an average of last ten years. Hence farmers were getting the price as equal to MSP. However MSP changes with constant increase ranges from 100.00 to 132.00 % to present year."

"Assessment of Farm Level Post-harvest Losses in Wheat in Haryana"

"The post – harvest losses have been evaluated at various levels in wheat grain in Haryana. Growth rate analysis was performed using time-series data on area, production, and productivity of the selected wheat crop from 2008-09 to 2017-18. The survey data obtained from 60 farmers in two districts in 2019-20 was used to estimate post-harvest losses. In each village, 15 people were chosen as responders. The influence of socio-economic factors on post-harvest losses at the farm level was investigated using functional analysis, whilst post-harvest losses at various levels were quantified using tabular analysis. At the state level, the yearly growth rates of area, production, and productivity rose by 0.43, 0.73, and 0.30 percent, respectively. Wheat post-harvest damages where calculated to be 3.47, 3.41, and 3.44 kg/quintal in Hisar, Karnal, and overall respectively. In both the districts and the state as a whole, the damages were largest during wheat combine harvesting. The variables that have a significant influence on post-harvest damages at the farm level, as well as certain policy implication, have been identified. As far as losses in monitory term is concerns, ` 335.45 crores were calculated in combine harvesting which is highest of the total post-harvest losses followed by Threshing (210.52). Storage, on the other hand, saw the least losses, accounting for 19.66 per cent of total post-harvest losses. Post-harvest losses in the state as a whole were anticipated to be ` 735.82 crores."

Comparative study of two bioassays with weakened duckweed and yeast treated with homeopathic preparations

In homeopathic basic research, the question as to the most adequate test systems and apt methodology is still open.
 This investigation examined the hypothesis that more complex organisms show stronger reactions to homeopathic remedies than less complex ones.
 We compared two Arsenic (As5+) stressed bioassays with duckweed (Lemna gibba, a multi-cellular autotrophic organism) and yeast (Saccharomyces cerevisiae, a single-cellular heterotrophic organism) regarding their response to homeopathic preparations [1].
 For duckweed, growth rates of leaf area and leaf number were evaluated. For yeast, growth kinetics were determined by measuring slope, yield and Et50 (point in time when yield was half maximum) of the sigmoid growth curve. The experiments with duckweed and yeast were performed in parallel (same day, same location and identical homeopathic preparations).
 After screening 17 substances, three homeopathic preparations (Arsenicum album, nosode, gibberellic acid) were chosen for repeated experimental series [2]. Five independent experiments were conducted for each remedy with both organisms in parallel. Potency levels used were in the range of 17x–33x for duckweed and 17x–30x for yeast. To control for test system stability, systematic negative control experiments were conducted over the complete experimentation period. All experiments were blinded and randomized.
 The systematic negative control experiments did not yield any significant effects. Application of potentized Arsenicum album in the duckweed bioassay yielded the largest effects compared to water controls without remedies for the parameters leaf area and leaf number (p

Renewable organic waste as substrate conditioning for the production of Euterpe oleracea seedlings

Forest restoration has the premise of restoring degraded native vegetation to conditions prior to degradation. The objective of this work was to evaluate the production of seedlings of a native species from the Amazon biome (Euterpe oleracea) under different substrates. The experiment was carried out at the Federal University of Tocantins, using a completely randomized design, and a 5x 4 factorial scheme, with five substrates (babassu stem + soil, babassu stem + rice husk + soil, coconut fiber + soil, babassu stem + fiber coconut + rice husk + soil, commercial substrate + soil - control), four trial periods (50, 100, 150 and 200 days). The evaluated variables: plant height, stem diameter, shoot dry matter, root dry matter, total dry matter, seedling quality index, leaf area and absolute growth rate. The growth of assai seedlings was influenced by the different substrates, until the 150 days after transplanting the quality and development of the seedlings were the same, both for the treatments that used commercial substrate and for the treatments that used renewable materials in their composition. The treatment using babassu stem (T1) obtained better shoot dry matter, total dry matter and seedling quality index values, in addition to being a material found in abundance in the regions, making this treatment the most viable and recommended for the production of assai seedlings.

Growth, Instability and Decomposition Analysis of Nutri Cereals in Tamil Nadu

Aim: The study was undertaken to know the growth rate, instability, and contribution of area and yield on the production of Nutri cereals.
 Place and Duration: The study was based on the secondary data for the period of 20 years (2001- 2020) for Tamil Nadu. Data has been collected from Agricultural statistics at a glance (2020), Season and Crop report (2020).
 Methodology: The growth rate of Nutri cereals can be estimated through compound annual growth rate, instability is measured using Coppock’s instability index and contribution of area and yield on production is studied using decomposition analysis.
 Results: Results revealed that Nutri cereals growth rate is found to be negative in first decade and positive in second decade Production of Nutri cereals in both the decades found positive in decline trend. The trend of productivity seems positive for both the decades at declining rate. Instability index is higher in terms of production than area and productivity. Area effect was most responsible for the production of Nutri cereals than yield and interaction effect.
 Conclusion: The area effect is more responsible for production of Nutri cereals. Area effect on production of Nutri cereals is high, hence government should intervene in this regard to improve the area of Nutri cereals cultivation.

Growth and instability in area, production and productivity of major spices in Bangladesh

The present study was conducted to analyze the trend in growth and instability of major spices in Bangladesh for the last 58 years from 1961-70 to 2011-18. A Semi-log regression model was used to assess the growth and trend of major spices (onion, garlic, chili, and ginger), while auto-correlation problems were solved using the Prais-Winsten transformation. An instability analysis was performed by generating the Cuddy Della instability index. The study observed that all the spices had a positive but low growth rate in area and production, where the highest values were only 3.04% and 3.97% per annum, respectively, for onion. Even the productivity of the spices was below 1% except for chili. Therefore, every year, the country has to import large amounts of spices from abroad to meet the demand of its population. Moreover, most spices were found instable in terms of area, production and productivity over time. Therefore, proper policies should be formulated to make the country self-sufficient in the spice sector than resort to imports by reducing instability and increasing the production of spices. • Prais-Winston transformation method were used to solve autocorrelation problem. • Highest production and growth rate were found for onion crops. • Garlic production and yield were relatively stable than other spice crops.

Can a large‐landscape conservation vision contribute to achieving biodiversity targets?

AbstractFounded in 1993, the Yellowstone to Yukon (Y2Y) vision was one of the earliest large‐landscape conservation visions. Despite growing recognition of large‐landscape conservation strategies, there have been few tests to date of conservation gains achieved through such approaches. We tested for conservation gains in the Y2Y region of North America following initiation of the Y2Y conservation vision in 1993 using a counterfactual spatiotemporal comparison and tracking change in five different conservation metrics. First, we enumerated the area of land within Y2Y in designated protected areas. We then compared the rate of change of protected area growth before‐ and after‐initiation of Y2Y in 1993 and to two adjacent counterfactual regions. Protected areas in the Y2Y grew by 7.8%, increasing by 107,289 km2, exceeding the Aichi target of 17% of the area under protection by 2018. More importantly, the rate of protected area growth increased 90% following initiation of the Y2Y large‐landscape conservation vision in 1993, whereas protected area growth declined in adjacent regions, or remained constant throughout North America. Sustained growth in protected areas and private land conservation was complemented by expansion of endangered grizzly bears in the U.S. portion of Y2Y, the greatest global expansion from zero to at least 117 wildlife road‐crossing structures and growing mainstreaming coverage of the Y2Y vision. Our counterfactual comparison provides valuable evidence that large‐landscape conservation strategies such as Y2Y can enhance protected area growth and other conservation metrics. We conclude that large‐landscape conservation strategies may be a useful model for achieving global large‐landscape conservation and biodiversity conservation targets.

Growth and instability analysis of major crops in Nepal

Agriculture production growth is dependent on various factors as policies, inputs, and the environment. It is imperative to compute growth rate for the formulation of plans, policies and strategies to boost production performance. This study examined the compound growth rate and instability index of major crops in Nepal. The time-series data of 29 years from 1990/91 to 2018/19 was analysed by dividing the total time period into three sub-periods of three decades. The instability of most of the crops' area, production, and productivity declined during the second sub-period and increased in the third sub period. The growth rate of the area, production, and productivity of the crops declined during the second sub-period except for maize, potato, and vegetables. During the third sub-period, only sugarcane, oilseeds, and maize area growth rate risen whereas the growth rate of production increased for sugarcane, oilseed, lentil, and rice. For the better production performance of crops, crop-specific strategies regarding area expansion and technological intervention should be promulgated.

DETECTION AND SPATIAL ANALYSIS OF LAND-USE: A CASE OF BUTUAN CITY WITH HISTORY OF MAJOR INFORMAL SETTLEMENTS

Abstract. This study detects the significant informal settlements in Butuan City proper. It determines the growth rate in 15 years with the given five-year interval. Machine learning algorithms and spatial analysis were applied to obtain the possible locations of informal settlement buildings. The projected locations of informal settlement buildings were validated thru aerial image validation using Remote Sensing and GIS-based techniques in ArcGIS software. Eight (8) barangays satisfy all the informal settlement building characteristics during the aerial validation process and ground-truthing, namely, Golden Ribbon, Holy Redeemer, Limaha, New Society, Ong Yiu, Port Puyohon, San Ignacio, and Tandang Sora. The eight (8) barangays were manually digitized from the given 5-years interval from 2005, 2010, 2015, and 2010. The value of the major informal settlement buildings area was computed to excel. The area growth rate was calculated using the growth rate formula. This study showed that the significant informal settlement in the study area increased. Among the eight (8) focused barangays, Tandang Sora ranked the highest informal settlements growth from 2005 to 2020. Its area increases up to 178.52%, a total of 24,608.43 square meters. Finally, the results revealed that the area of informal settlement buildings in Butuan City from 2005–2020, in 15-years, its value increases up to 9.74%, a total of 19,172.88 square meters.

Growth Rate Estimation of Rabi Pulse Production of Odisha by Using Spline Regression Technique

Pulses are considered to be important crop for ensuring nutritional security in Odisha. Proper estimation of growth rate in production of pulse crops allows for more effective cropping system planning and formulation of the agricultural policy of the state. To capture any abrupt changes and the variation in data in different phases of a long time period, spline regression technique is used as it can fit different models in different segments of the time period as necessary without losing the continuity of the model. The present study deals with the estimation of growth rate of area, yield and production of all rabi pulses in Odisha by using best fit spline regression model. To fit the spline regression model, the entire period of study is divided into different segments based on the scatter plot diagram which is further confirmed by testing the significance of change in coefficient of variation between the consecutive segments by chi square test. The regression model found to be suitable from the study of scatter plot of data are linear, compound, logarithmic, power, quadratic and cubic model. The best fit model is selected on the basis of error assumption test and model fit statistics such as R2, adjusted R2 and Mean Absolute Percentage error (MAPE). The respective selected best fit model is used for the estimation of growth rates of area, yield and production of rabi pulses in Odisha for each segment and the whole period of study. Among the spline regression models, the respective linear spline regression model is found to be best fit for area, yield and production of rabi pulses and are used for growth rate estimation of these variables. It is found that though the growth rate in area and yield of rabi pulses are not significant, the growth rate of production is found to be significant for the whole period of study which shows that the interaction effect of area and yield on production seems to dominate.

Modelling Maximum Stem Basal Area Growth Rates of Individual Trees ofEucalyptus pilularisSmith

AbstractThe growth rate of a tree at any time relates to its size and the level of competition exerted by its neighbors for the resources it needs for growth. This work describes the development of a model to predict the maximum growth rate in stem basal area of Eucalyptus pilularis Smith trees in native and plantation forests of subtropical eastern Australia. It shows maximum growth rates increasing with size until the tree reaches a stem diameter at breast height of 27 cm. Thereafter, maximum growth rates decline progressively as the tree grows larger. Physiological reasons that might describe this growth pattern are discussed. The maxima are shown to be independent of tree age, stand stocking density or average tree size, and the productive capacity of the site on which the forest is growing.

Analytical Study of Kharif Food Grain Production in Odisha

The state of Odisha having an agrarian based economy depends largely on agriculture for the livelihood of its population. Food grains are important commodity of crop groups that provide high quality carbohydrates, protein and vitamins. A study on the compound growth rate of area, yield and production of food grains for kharif season in the districts of Odisha and the state as a whole has been attempted in the present study which would be helpful in visualizing the progress of the state with respect to food grain cultivation and proper framing of agricultural policies of the state. The study is based secondary data for the period of 1993-94 to 2017-18 to estimate the compound growth rate and Cuddy-Della Instability Index of area, yield and production of kharif food grains for the districts and the state as a whole. The districts are ranked on the basis of compound growth rate and Cuddy-Della Instability Index in decreasing order and increasing order of their magnitudes respectively. The rank correlation between Compound Growth Rate and Cuddy-Della Instability Index of area, yield and production of food grains during kharif seasons are studied. It is found that despite negative growth rate in area, the positive compound growth rate of yield leads to positive compound growth rate in production of kharif food grains of Odisha. Also it is found that despite stability of area, the instability of yield leads to instability in production of kharif food grains in the state of Odisha.

Analysis Growth Rate in Area, Production and Productivity of Sapota in Gujarat, India

The present investigation was "Analysis growth rate in area, production and productivity of Sapota in Gujarat". A multi stage random sampling design was used for selecting the sample. The study covered 2 Districts, 2 talukas, 12 villages and 120 Sapota growers from Valsad and Navsari districts. The primary data were collected for the season of 2011-2012 by personal interview method. In the results revealed that the Valsad and Navsari districts were found to having positive growth rate in area and production (0.20 and 0.73 per cent and 1.59 and 2.30 per cent, respectively). While the productivity of both the districts was positive viz., 0.54 and 0.70 respectively. On the contrary, a lower but positive and significant growth rate was observed in sapota area for the state as a whole, whereas the production and yield showed positive trend (2.01 and 2.55 respectively). The per hectare total cost of establishment for four year were Rs. 75387.59 for the orchards in Valsad district and Rs. 74025.27 for the orchards in Navsari district. The maintenance cost worked out to be as Rs. 56326.59 and Rs. 55298.27 in Valsad and Navsari district respectively. The average per ha yield from Valsad district was 10. 61 tonnes and from Navsari district was 11.11 tonnes in 6th year and net returns were Rs. 113527 from Valsad district and Rs. 118877 from Navsari district.

Numerical analysis of molten metal behavior and undercut formation in high-speed GMAW

• A self-adaptive integrated arc heat-force distribution model is developed for GMAW. • Backward flow, gouging region and thin metal layer are processes initiating undercut. • Two dimensionless numbers are developed to predict the growth rate of undercut. A computational fluid dynamics model was established to investigate the undercut formation in high speed gas metal arc welding (GMAW). A double-ellipse integrated "arc current density-arc pressure-electromagnetic force-arc heat" distribution model, which could be self-adaptive to weld pool surface evolution, was developed. The multi-coupling transport phenomena in weld pool were simulated, and the effect of driving forces on the behaviors of molten metal and the formation of undercut was analyzed quantitatively. The results show that the high-velocity backward molten metal flow, large-size gouging region and prematurely solidified thin metal layer at weld toe were typical processes that initiated undercut. The evolution of undercut morphology was determined by the characteristics of inertia force, hydrostatic pressure and arc pressure in the different stages. Based on Buckingham- π theorem, the dimensionless growth rate of undercut area was a parabolic function of a dimensionless group including characteristics of stress state, molten metal flow and morphology of weld pool. This study clarified the physical origin of undercut defect in GMAW and might also provide some basic guidelines for its suppression.