POSSIBILITY OF EARLY COMMENCEMENT OF TAPPING IN RUBBER (HEVEA BRASILIENSIS) USING DIFFERENT GENOTYPES AND TAPPING SYSTEMS

2007 ◽  
Vol 43 (2) ◽  
pp. 201-221 ◽  
Author(s):  
H. K. L. K. GUNASEKARA ◽  
E. A. NUGAWELA ◽  
W. A. J. M. DE COSTA ◽  
D. P. S. T. G. ATTANAYAKE
Keyword(s):  
Flow Rate ◽  
Hevea Brasiliensis ◽  
Yield Components ◽  
Low Frequency ◽  
The Other ◽  
Yield Response ◽  
Rubber Content ◽  
Rubber Production ◽  
Significant Yield ◽  
Lower Stem

The feasibility of commencing tapping (‘opening’) of rubber trees for latex extraction at a lower stem girth (40 and 45 cm) than the currently recommended 50 cm was investigated in three different genotypes. The possibility of combining early opening with low frequency tapping and yield stimulation using Ethrel (LFT + E) was also examined. One of the genotypes tested, RRIC 121, gave a higher dry rubber yield, both per tapping and cumulatively over a given period, when opened at 40 cm than at 50 cm. Of the other two genotypes, one (RRISL 211) showed a clear reduction in yield with early opening, while the other (RRIC 102) did not show a significant yield response. Among the three genotypes tested, RRIC 121 showed the minimum depression in trunk girth increment. Analysis of yield components showed that the response of a given genotype to early opening and LFT + E is determined by the interaction between latex volume per tapping and dry rubber content (DRC), which were negatively correlated. RRIC 121 had a significantly greater DRC, which enabled it to maintain a higher dry rubber yield under early opening and LFT + E despite producing a lower latex volume than both the other genotypes. In contrast, despite producing a substantially greater latex volume than the other two genotypes, RRISL 211 did not produce a higher dry rubber yield because of its lower DRC. The higher DRC was also responsible for the greater response of RRIC 121 to yield stimulation with Ethrel, which reduced the plugging index and increased the initial latex flow rate. Early commencement of tapping in combination with LFT + E is therefore possible in rubber when amenable genotypes are selected, offering the potential of improving the economics of rubber production, especially for smallholders, in West Asia.

Responses of Yield, Components of Yield and Nutrient Content of Maize to Soil-Applied Zinc in Tropical Rainforest and Savannah Regions

1985 ◽  
Vol 105 (1) ◽  
pp. 135-139 ◽  
Author(s):  
G. O. Kayode
Keyword(s):  
Yield Components ◽  
Nutrient Content ◽  
Yield Component ◽  
Yield Response ◽  
Old Field ◽  
Forest Zone ◽  
Maize Production ◽  
P Concentration ◽  
Significant Yield ◽  
The Tropics

SUMMARYResults of a 2-year studyin the rainforest and savannah zones of Nigeria todetermine the responses of yield, components of yield and nutrient content of maize to soilapplied zinc showed that Zn significantly increased yield in the new and old savannah soils, whereas significant yield response was recorded only in an old field of the forest zone. Ear weight was the only yield component significantly influenced by Zn treatments in the two zones. Application of 2·5 kg Zn/ha appears adequate for successful maize production in the savannah and old forest zones in the tropics.Soil-applied Zn significantly increased ear-leaf N and Zn, but P concentration was significantly decreased. Grain yield was positively correlated with ear-leaf Zn.

scholarly journals Effect of seasonal and environmental variation on yield and yield components of hybrid Maize

2015 ◽  
Vol 4 (2) ◽  
pp. 1-5
Author(s):  
MK Islam ◽  
MS Mahfuz ◽  
MAI Sarker ◽  
S Ghosh ◽  
ASMY Ali
Keyword(s):  
Yield Components ◽  
The Other ◽  
Growth And Yield ◽  
Rabi Season ◽  
Environment Effect ◽  
Yield Parameters ◽  
Maize Varieties ◽  
Significant Yield ◽  
Lower Temperature ◽  
Hybrid Maize

The experiment was conducted during kharif II in 2006 & 07, rabi in 2006-07 & 07-08 and kharif I in 2007 and 2008 at ARS, Burirhat, Rangpur in RCB design to understand the influence of season and location specific environment effect on growth and yield of hybrid maize and selected suitable variety(s). Four hybrid maize varieties V1=BARI hybrid Maize (BHM)-2, V2=BHM-3, V3= BHM-5 and V4= Pacific-984 (as check) were tested during kharif II in 2006 while seven varieties V1= BHM-2, V2= BHM-3, V3= BHM-5 and V4= Pacific-984, V5= Pacific-60, V6= Pacific-11 and V7= Prolin were during the other seasons except rabi, 07- 08, where variety Pacific-555 was used in V7 instead of Prolin. Seeds were sown on August 30 and August 11 for kharif II of 2006 and 2007, respectively, November 28 and 17 for rabi 2006-2007 and 2007-08 and March 08 and 12 for for kharif I 2007 and 2008. The crops were harvested on January 25, 2007 and January 12, 2008 in the two consecutive kharif II seasons; May 10 and April 29 in rabi 2006-07 and 2007-08, and July 01 and 05 in kharif I 2007 and 2008, respectively. Yield parameters were mostly varied significantly. The highest yield was obtained from BHM-5 (9.03 t ha-1), which was followed by Pacific-984 (8.89 t ha-1), BHM-3 (8.81 t ha-1) and BHM-2 (8.58 t ha-1) in kharif II, 2006 while in kharif II, 2007 the highest significant yield was noted in Pacific-984 (9.22 t ha-1). In rabi, 2006-07, significant highest grain yield was obtained from Pacific-60 (11.03 t ha-1), which was statistically identical with Prolin (10.20 t ha-1). The yield of Prolin was also statistically identical with Pacific-11 (10.01 t ha-1), BHM-5 (10.00 t ha-1), BHM-3 (9.92 t ha-1) and BHM-2 (9.51 t ha-1). Comparatively lower temperature during ear initiation (mean 29.6°C in rabi and 31°C in kharif II) and silking (mean 18.2°C in rabi and 20.2°C in kharif II) contributed much for higher trend of yield in rabi over kharif. In kharif I, 2007, the highest yield (9.55 t ha-1) was recorded from Pacific-60, which was identical to Pacific-984 (9.25 t ha-1), BHM-5 (9.11 t ha-1) and BHM-3 (8.89 t ha-1). All the BARI hybrid maize varieties were suitable to grown in kharif I, kharif II and rabi season although BHM-3, BHM-5, Pacific-60 and Pacific-984 were better in Kharif I and Pacific-60, BHM-5, Prolin and Pacific-555 were found better in Rabi season. DOI: http://dx.doi.org/10.3329/ijarit.v4i2.22635 Int. J. Agril. Res. Innov. & Tech. 4 (2): 1-5, December, 2014

scholarly journals Heritability of Yield and Secondary Traits in two populations of Para Rubber Tree (Hevea brasiliensis)

2011 ◽  
Vol 60 (1-6) ◽  
pp. 132-139 ◽  
Author(s):  
C. Narayanan ◽  
Kavitha K. Mydin
Keyword(s):  
Flow Rate ◽  
Hevea Brasiliensis ◽  
Yield Components ◽  
Growth Traits ◽  
Rubber Tree ◽  
Indirect Selection ◽  
Bark Thickness ◽  
Peak Period ◽  
High Heritability ◽  
Yield Depression

AbstractHeritability and interactions of yield and growth traits were assessed in Hevea brasiliensis using full-sib progenies and clonal populations. Using parent-offspring regression, annual mean rubber yield (ARY) and summer yield (SY) showed moderate to high heritability (ARY, h2 =34–56%; SY, h2 =36–52%). Among the yield components, girth exhibited low to moderate heritability (h2 =17–36%) while branching height showed low heritability (h2 =18%). Using forty clonal genotypes, annual mean rubber yield (H2=48%), rubber yield during peak period (H2=47%) and rubber yield during stress (or summer yield) (H2=44%) showed high estimates of heritability. Among the other yield components, except volume of latex during stress period (H2=40%), remaining yield components showed moderate estimates for heritability (H2=29–37%). Dry rubber content (DRC) based on annual mean showed very high heritability (H2=68%), followed by DRC during stress (H2=51%) and peak (H2=50%) periods. Latex flow rate based on annual mean and peak period data showed high heritability (H2=51%) followed by latex flow rate during stress period (H2=42%). Plugging indices of annual and stress period showed high heritability (H2=43%) than that of peak period (H2=25%). Regarding growth traits, girth showed high heritability (H2=50%) than girth increment (H2=32%). While bark thickness showed high heritability (H2=40%) length of tapping panel showed moderate heritability (H2=27%). Total chlorophyll content exhibited moderate heritability (H2=22%); chlorophyll pigment ratio showed low heritability (H2=5%). Based on parent-offspring analysis, annual mean rubber yield exhibited high genetic correlation with summer yield and girth. Annual mean rubber yield and summer yield were negatively correlated with branching height. Regarding phenotypic correlations among the forty clonal genotypes, annual mean rubber yield exhibited high correlation with latex volume, latex flow rate, DRC, girth and bark thickness. However, annual mean rubber yield was negatively correlated with yield depression under stress and plugging index. Rubber yield, volume and rate of flow of latex over the three periods, yield depression under stress, girth increment, annual mean plugging index and plugging index under stress showed high estimates of genetic advance. The high estimates of heritability for yield and its components coupled with their high genetic gain indicated that considerable improvement can be achieved for these traits through selection. Estimates for indirect selection efficiency were not optimal for indirect selection for yield using girth and summer yield.

scholarly journals Backflow effects on mass flow gain factor in a centrifugal pump

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042199886
Author(s):  
Wenzhe Kang ◽  
Lingjiu Zhou ◽  
Dianhai Liu ◽  
Zhengwei Wang
Keyword(s):  
Centrifugal Pump ◽  
Mass Flow ◽  
Flow Rate ◽  
Low Frequency ◽  
Gain Factor ◽  
Low Flow ◽  
Cavity Volume ◽  
Cavitating Flows ◽  
Inlet Tube ◽  
Low Flow Rate

Previous researches has shown that inlet backflow may occur in a centrifugal pump when running at low-flow-rate conditions and have nonnegligible effects on cavitation behaviors (e.g. mass flow gain factor) and cavitation stability (e.g. cavitation surge). To analyze the influences of backflow in impeller inlet, comparative studies of cavitating flows are carried out for two typical centrifugal pumps. A series of computational fluid dynamics (CFD) simulations were carried out for the cavitating flows in two pumps, based on the RANS (Reynolds-Averaged Naiver-Stokes) solver with the turbulence model of k- ω shear stress transport and homogeneous multiphase model. The cavity volume in Pump A (with less reversed flow in impeller inlet) decreases with the decreasing of flow rate, while the cavity volume in Pump B (with obvious inlet backflow) reach the minimum values at δ = 0.1285 and then increase as the flow rate decreases. For Pump A, the mass flow gain factors are negative and the absolute values increase with the decrease of cavitation number for all calculation conditions. For Pump B, the mass flow gain factors are negative for most conditions but positive for some conditions with low flow rate coefficients and low cavitation numbers, reaching the minimum value at condition of σ = 0.151 for most cases. The development of backflow in impeller inlet is found to be the essential reason for the great differences. For Pump B, the strong shearing between backflow and main flow lead to the cavitation in inlet tube. The cavity volume in the impeller decreases while that in the inlet tube increases with the decreasing of flow rate, which make the total cavity volume reaches the minimum value at δ = 0.1285 and then the mass flow gain factor become positive. Through the transient calculations for cavitating flows in two pumps, low-frequency fluctuations of pressure and flow rate are found in Pump B at some off-designed conditions (e.g. δ = 0.107, σ = 0.195). The relations among inlet pressure, inlet flow rate, cavity volume, and backflow are analyzed in detail to understand the periodic evolution of low-frequency fluctuations. Backflow is found to be the main reason which cause the positive value of mass flow gain factor at low-flow-rate conditions. Through the transient simulations of cavitating flow, backflow is considered as an important aspect closely related to the hydraulic stability of cavitating pumping system.

Pressure Drop Measurements for Air Flow Through Open-Cell Aluminum Foam

2004 ◽  
Author(s):  
Nihad Dukhan ◽  
Angel Alvarez
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Flow Rate ◽  
Aluminum Foam ◽  
Flow Direction ◽  
The Other ◽  
Turbulent Regime ◽  
Thick Sample ◽  
Open Cell ◽  
Two Samples

Wind-tunnel pressure drop measurements for airflow through two samples of forty-pore-per-inch commercially available open-cell aluminum foam were undertaken. Each sample’s cross-sectional area perpendicular to the flow direction measured 10.16 cm by 24.13 cm. The thickness in the flow direction was 10.16 cm for one sample and 5.08 cm for the other. The flow rate ranged from 0.016 to 0.101 m3/s for the thick sample and from 0.025 to 0.134 m3/s for the other. The data were all in the fully turbulent regime. The pressure drop for both samples increased with increasing flow rate and followed a quadratic behavior. The permeability and the inertia coefficient showed some scatter with average values of 4.6 × 10−8 m2 and 2.9 × 10−8 m2, and 0.086 and 0.066 for the thick and the thin samples, respectively. The friction factor decayed with the Reynolds number and was weakly dependent on the Reynolds number for Reynolds number greater than 35.

scholarly journals Nucleotide Variation at theCHALCONE ISOMERASELocus inArabidopsis thaliana

Genetics ◽  
2000 ◽  
Vol 155 (2) ◽  
pp. 863-872 ◽  
Author(s):  
Helmi Kuittinen ◽  
Montserrat Aguadé
Keyword(s):  
Nucleotide Diversity ◽  
Direct Relationship ◽  
Selective Sweep ◽  
Balancing Selection ◽  
Neutral Theory ◽  
Low Frequency ◽  
The Other ◽  
Nucleotide Variation ◽  
Rapid Population Growth ◽  
History Of

AbstractAn ~1.9-kb region encompassing the CHI gene, which encodes chalcone isomerase, was sequenced in 24 worldwide ecotypes of Arabidopsis thaliana (L.) Heynh. and in 1 ecotype of A. lyrata ssp. petraea. There was no evidence for dimorphism at the CHI region. A minimum of three recombination events was inferred in the history of the sampled ecotypes of the highly selfing A. thaliana. The estimated nucleotide diversity (θTOTAL = 0.004, θSIL = 0.005) was on the lower part of the range of the corresponding estimates for other gene regions. The skewness of the frequency spectrum toward an excess of low-frequency polymorphisms, together with the bell-shaped distribution of pairwise nucleotide differences at CHI, suggests that A. thaliana has recently experienced a rapid population growth. Although this pattern could also be explained by a recent selective sweep at the studied region, results from the other studied loci and from an AFLP survey seem to support the expansion hypothesis. Comparison of silent polymorphism and divergence at the CHI region and at the Adh1 and ChiA revealed in some cases a significant deviation of the direct relationship predicted by the neutral theory, which would be compatible with balancing selection acting at the latter regions.

scholarly journals Large Eddy Simulation of Periodic Transient Pressure Fluctuation in a Centrifugal Pump Impeller at Low Flow Rate

Symmetry ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 311
Author(s):  
Renfei Kuang ◽  
Xiaoping Chen ◽  
Zhiming Zhang ◽  
Zuchao Zhu ◽  
Yu Li
Keyword(s):  
Large Eddy Simulation ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Pressure Fluctuation ◽  
Low Frequency ◽  
Pump Impeller ◽  
Eddy Simulation ◽  
Inlet Flow Rate ◽  
Large Eddy ◽  
Centrifugal Pump Impeller

This paper presents a large eddy simulation of a centrifugal pump impeller during a transient condition. The flow rate is sinusoidal and oscillates between 0.25Qd (Qd indicates design load) and 0.75Qd when the rotating speed is maintained. Research shows that in one period, the inlet flow rate will twice reach 0.5Qd, and among the impeller of one moment is a stall state, but the other is a non-stall state. In the process of flow development, the evolution of low-frequency pressure fluctuation shows an obviously sinusoidal form, whose frequency is insensitive to the monitoring position and equals to that of the flow rate. However, inside the impeller, the phase and amplitude in the stall passages lag behind more and are stronger than that in the non-stall passages. Meanwhile, the strongest region of the high-frequency pressure fluctuation appears in the stall passages at the transient rising stage. The second dominant frequency in stall passages is 2.5 times to that in non-stall passages. In addition, similar to the pressure fluctuation, the evolution of the low-frequency head shows a sinusoidal form, whose phase is lagging behind that by one-third of a period in the inlet flow rate.

Optimization of Inlet Ring Groove Arrangement for Suppression of Unstable Flow in a Centrifugal Impeller

2005 ◽  
Author(s):  
Masahiro Ishida ◽  
Daisaku Sakaguchi ◽  
Hironobu Ueki
Keyword(s):  
Flow Rate ◽  
The Other ◽  
Centrifugal Impeller ◽  
Shape Parameters ◽  
Unstable Flow ◽  
Ring Groove ◽  
Flow Rates ◽  
Small Flow ◽  
Specific Speed ◽  
Large Flow

An optimization of the inlet ring groove arrangement has been pursued in the present study for obtaining better impeller characteristics and a wider operation range at both small and large flow rates in a high specific speed type centrifugal impeller with inducer. The effects of the shape parameters with respect to the inlet ring groove on the impeller characteristic and the flow incidence were analyzed mainly based on numerical simulations, but also compared to the experimental results. At small flow rates, a significant improvement in the impeller characteristic is achieved due to reduction in the excessive-positive flow incidence by optimizing both location and width of the rear groove near the inducer tip throat. On the other hand, the impeller characteristic is improved at large flow rates by implementing the corner radius at the rear groove edge and by placing another front ring groove in the suction pipe. As a result, by the optimized configuration of the front and rear ring grooves, the unstable flow range of the test impeller can be reduced by about 50% without deterioration of the impeller characteristic even at the 125% flow rate.

Transverse dam-break waves

2014 ◽  
Vol 758 ◽  
Author(s):  
S. Karimpour Ghannadi ◽  
Vincent H. Chu
Keyword(s):  
Froude Number ◽  
Flow Rate ◽  
Main Flow ◽  
Dam Break ◽  
The Other ◽  
Water Diversion ◽  
The Family ◽  
The One ◽  
Limiting Case ◽  
The Waves

AbstractNumerical simulations of the transverse dam-break waves (TDWs) produced by the sudden removal of a gate on the side of a waterway are conducted based on the shallow-water equations to find solutions to a family of water-diversion problems. The Froude numbers in the main flow identify the members of the family. The depth and discharge profiles are analysed in terms of Ritter’s similarity variable. For subcritical main flow, the waves are comprised of a supercritical flow expansion followed by a subcritical outflow. For supercritical main flow, on the other hand, the waves are analogous to the Prandtl–Meyer expansion in gas dynamics. The diversion flow rate of two-dimensional TDWs on a flat bed is 55 % greater than the one-dimensional flow rate of Ritter in the limiting case of zero main flow, and approaches the rate of Ritter in the other limit when the value of the Froude number in the main flow approaches infinity. The diversion flow rate over a weir is generally higher than the rate over a flat bed depending on the Froude number of the main flow. These numerical simulation results are consistent with laboratory observations.

scholarly journals Dynamics and Protein–Solvent Interactions of Hemoglobin in T and R Quaternary Conformation

2002 ◽  
Vol 16 (3-4) ◽  
pp. 227-233 ◽  
Author(s):  
Chiara Caronna ◽  
Antonio Cupane
Keyword(s):  
Quaternary Structure ◽  
Dynamic Properties ◽  
Low Frequency ◽  
Helical Structure ◽  
Blue Shift ◽  
Peak Frequency ◽  
The Other ◽  
Solvent Interactions ◽  
Reported Data ◽  
Increasing Temperature

In this work we report the thermal behaviour of the amide I′ band of carbonmonoxy and deoxy hemoglobin in 65% v/v glycerolD8/D2O solutions and in the temperature interval 10–295 K. Following recent suggestions in the literature, we analyze the amide I′ band in terms of two components, one at about 1630 cm−1and the other at about 1650 cm−1, that are assigned to solvent‒exposed and buried α‒helical regions, respectively.For deoxy hemoglobin (in T quaternary structure) both components are narrower with respect to carbonmonoxy hemoglobin (in R quaternary structure), while the peak frequency blue shift observed, upon increasing temperature, for the component at about 1630 cm−1is smaller. The reported data provide evidence of the dependence of hemoglobin dynamic properties upon the protein quaternary structure and suggest a more compact α‒helical structure of hemoglobin in T conformation, with reduced population of low‒frequency modes involving the solvent and protein.

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