Filling Stage Research Articles

Flow Characteristics of Vacuum Assisted Resin Transfer Molding Process Depending on the Capillary Phenomenon

Reducing the cost of composite material production is significant for expanding its usage and application in many ways, such as in the fields of aerospace, aviation, ocean industry and so on. To do this, It is important to minimize the production process of the material and to decrease the amount of scraps or any unnecessary particles. The Vacuum Assisted Resin Transfer Molding (VARTM) process, which is known for having many advantages, has become recognized as one of the most low-cost manufacturing model. VARTM process can be divided into three main steps: performing, resin filling and hardening steps. The most important step among all these three steps is the Resin Filling stage, a process when resin is impregnated into the mat. Mostly, Resin Filling stage is greatly affected by the level of permeability, a characteristic of stiffener due to pneumatic resistant nature in the process. Other factors such as viscosity, technological vacuuming, or even stiffening process itself could also influence the production as well. During Resin Filling stage, Resin tends to spread out in the center first because of capillary phenomenon. In this research, the researchers examined the mechanical property and the pneumatic nature of Resin by dividing the pneumatic movement of the Resin into sections. Based on this result, the researchers found the correlations between the capillary phenomenon and Resin impregnation, and analyzed the movement mechanism in Resin filling stage.

Influence of High Temperature Stress on Net Photosynthesis, Dry Matter Partitioning and Rice Grain Yield at Flowering and Grain Filling Stages

Climate change is recognized to increase the frequency and severity of extreme temperature events. At flowering and grain filling stages, risk of high temperature stress (HTS) on rice might increase, and lead to declining grain yields. A regulated cabinet experiment was carried out to investigate effects of high temperature stress on rice growth at flowering and grain-filling stages. Results showed that no obvious decrease pattern in net photosynthesis appeared along with the temperature rising, but the dry matter allocation in leaf, leaf sheath, culm, and panicle all changed. Dry weight of panicle decreased, and ratio of straw to total above ground crop dry weight increased 6–34% from CK, which might have great effects on carbon cycling and green house gas emission. Grain yield decreased significantly across all treatments on average from 15 to 73%. Occurrence of HTS at flowering stage showed more serious influence on grain yield than at grain filling stage. High temperature stress showed negative effects on harvest index. It might be helpful to provide valuable information for crop simulation models to capture the effects of high temperature stress on rice, and evaluate the high temperature risk.

Varietal Differences in Cell Wall β-(1→3),(1→4)-Glucan and Nonstructural Carbohydrate in Rice Stems during the Grain Filling Stage

The contribution of cell wall components and nonstructural carbohydrate (NSC) to grain filling in rice (Oryza sativa L.) was clarified by investigating the differences in the dynamics of hemicellulose, sugar composition of hemicellulose, β-(1→3),(1→4)-glucan, and NSC among cultivars with different grain filling capacities. This investigation was performed using the stems of standard, high yield and low harvest index (HI) cultivars. Hemicellulose concentration in stems tended to decrease slightly during the grain filling stage. This decrease was attributed to a decrease in β-(1→3),(1→4)-glucan concentration, which was detected as a decrease in glucose composition of hemicellulose in the stems during the grain filling stage. The rate of decrease and decrease in the amount of β-(1→3),(1→4)-glucan in the stems differed among the cultivars. These were higher in high yield and high HI cultivars than in relatively low yield and low HI cultivars. Moreover, a positive correlation was observed between the rate of decrease in β-(1→3),(1→4)-glucan and NSC, indicating similarities in the dynamics of β-(1→3),(1→4)-glucan and NSC among the cultivars. When the top half of panicle was removed, β-(1→3),(1→4)-glucan and NSC concentrations in the culm and leaf sheath did not decrease during the grain filling stage. Therefore, the β-(1→3),(1→4)-glucan in stems might be one of the sources that supply substrate to panicle as well as NSC.

Effect of Water Shortage and Increasing Nitrogen Application on Photosyn-thetic Function of Different Hybrid Rice Combinations at Grain Filling Stage

Effect of Water Shortage and Increasing Nitrogen Application on Photosyn-thetic Function of Different Hybrid Rice Combinations at Grain Filling Stage

Effect of Temperature during Grain Filling Stage on Endosperm Structure and Apperance Quality of Aromatic Rice

Based on the experiment of two inbred aromatic rice varieties and one hybrid aromatic rice line treated under four different temperatures( daymean temperature 21°C, 23°C, 26°C and 30°C respectively) during grain filling stage in phytotrons, the shape and arrangement of endosperm starch granules in rice grain transection were observed by scanning electron microscope and the related characteristics of rice grain qualities of chalky percent and chalkiness were analyzed at the same time. The results showed that under the lower temperature( daymean temperature21°C and 23°C), many large compound starch granules with clear angulars packed together regularly without significant natural gaps bewteen starch granules in the tansectional endosperm. However, with the increase of temperature, starch granules in the transectional endosperm were changed from regularly shaped and closely and orderly arranged to various shaped and chaoticly arranged with obvious natural gaps between starch granules, which was closely consistent with the poorer appearance quality under the higher temperature, which indicated that the endosperm structure is closely related with appearance quality of aromatic rice.

Effects of Nitrogen Application Strategy and Cultivation Model on the Per-formances of Canopy Apparent Photosynthesis of Indica Hybrid Rice Eryou 498 during Filling Stage

Effects of Nitrogen Application Strategy and Cultivation Model on the Per-formances of Canopy Apparent Photosynthesis of Indica Hybrid Rice Eryou 498 during Filling Stage

Effect of Abscisic Acid Treatment on <I>psbA</I> Gene Expression in Two Wheat Cultivars during Grain Filling Stage under Drought Stress

Effect of Abscisic Acid Treatment on <I>psbA</I> Gene Expression in Two Wheat Cultivars during Grain Filling Stage under Drought Stress

Effect of Exogenous Abscisic Acid on psbA Expression at Grain Filling Stage in Two Wheat Cultivars Under Drought Stress

Abscisic acid (ABA) is an important plant hormone and may be involved in drought resistance in crops. The object of this study was to understand the effects of exogenous ABA on wheat (Triticum aestivum L.) plant under drought stress. After drought stress simulated with polyethylene glycol (PEG) for 72 h at grain-filling stage, flag leaves of Yumai 949 and Shaanmai 5 showed significant increase in malondialdehyde (MDA) content and decreases in relative water content (RWC), chlorophyll content, and yield. Meanwhile, the transcription of psbA gene in photosystem II system was also depressed according to the analysis of reverse transcriptional PCR. Application of exogenous ABA had a significant effect on alleviation of these reactions from PEG stress. Compared to Yumai 949, Shaanmai 5 received smaller injury in plasma membranes and less reduces in RWC, chlorophyll content, yield, and psbA transcriptional level after PEG stress. Moreover, exogenous ABA treatment resulted in restoration of all parameters tested to the levels before stress in Shaanmai 5. This result indicated that the expression of psbA gene was closely related to drought stress resistance subject to wheat cultivar. The primary evidence of ABA regulation on psbA expression may enrich the mechanism of drought resistance and suggest the potential of exogenous ABA to enhance resistance to drought stress in wheat during grain filling period.

Interaction of Gravity Flows With a Rugged Mid-Ocean-Ridge Seafloor: An Outcrop Example from Macquarie Island

Rugged bathymetry along slow-spreading mid-ocean ridges has the potential to impinge a strong control on gravity flows derived from oceanic fault scarps. Sedimentary lithofacies from the Macquarie Island ophiolite supports this hypothesis by displaying systematic variations that correspond with volcanic substrate differences and proximity to rift-related faults. Pillow-basalt terranes are associated with tightly confined bedrock corridors that funnel gravity flows into one direction. Vertical lithofacies variations formed from high-density to low-density turbidity currents record successive fill stages of the corridor axis. During initial stages tight confinement in the axis suppressed flow dilution and fluid turbulence. With continued corridor-axis filling, more dilute gravity flows predominated and formed lateral gradations from axial coarse-grained turbidites into thinly interbedded overbank lithofacies along corridor margins. These gravity-flow lithofacies converge into very thin muddy condensed intervals along inter-corridor highs where significant bottom-current reworking occurred. Conversely, partly confined tabular-basalt-floored basins promoted lateral expansion and dilution of gravity flows throughout the duration of basin filling. Variable paleocurrent-indicator directions record multiple reflections of single gravity-flow events off basin-bounding fault barriers. Coarsening-upward trends in these partly confined basins from thinly interbedded pelagic chert and ripple-bedded sandstones up into stacked turbidites preserves the ponding of sediment-starved submarine fans. In general, these ponded basins preserve the fine-grained distal ends of a gravity-flow continuum from coarse-grained fault-proximal en masse failures and cohesionless debris flows into medial high-density turbidity flows and distal dilute turbidity flows.

Stress Effects of Simulated Acid Rain on Photosynthetic Characteristics and Yield of Field-grown Spring Wheat at the Filling Stage in Semi Arid Rain Feed Region

In order to investigate the effect of acid rain on photosynthetic characteristics of spring wheat,spring wheat at the filling stage was sprayed with simulated acid rain at different pH level of 1.5,2.5,3.5,4.5 and 5.6,and then,the yield and the photosynthetic parameters of spring wheat leaves were monitored.The results indicated:①The net photosynthetic rate reduces in the range of 9.61% to 61.50%,stomatal conductance reduces in the range of 7.03% to 57.46%,transpiration rate reduces in the range of 3.70% to 55.44%,intercellular CO2 concentration increases in the range of 27.91% to 43.74%,the chlorophyll relative content reduces in the range of 12.12% to 41.92%,the yield of spring wheat reduces in the range of 15.50% to 37.05%.Effect of simulated acid rain on photosynthetic characteristics of spring wheat leaves increases more and more remarkable with the increase of hydrogen ion concentration.②The pH values of simulated acid rain was significantly positively correlated with net photosynthetic rate,transpiration rate,stomatal conductance,the relative chlorophyll content and the yield,and the pH values of simulated acid rain was significantly negatively correlated with intercellular CO2 concentration.

Semi-empirical full cycle optimisation of fill, squeeze and blow plate and frame pressure filters

Investigation of the response of plate and frame filter performance to changes in design and operating variables is complicated by the large matrix of potential variables and the inter-dependent kinetics of the fill, press and air blow stages. However, through some key simplifying constraints an integrated optimisation framework has been developed. An example application is presented for an iron ore fines material from the North West of Australia, which indicates an optimum filling duration exists for all conditions investigated and illustrates the throughput benefits of higher feed solids and pressing pressures and larger cavity thicknesses. Significantly, the optimum filling duration is not constant and depends on the ratio of pressing to filling pressure and cavity thickness employed, largely due to the important role of the pressing stage not from the perspective of compression, but rather from that of an increased rate of secondary filtration of unfiltered suspension remaining at the end of the filling stage. Although simplistic in the form presented and limited to incompressible systems, with the integration of more rigorous theoretical treatments of the individual filter stages, the applicability of the approach could be broadened to all types of substrates.

Effects of Drought Stress on Activity of Photosystems in Leaves of Maize at Grain Filling Stage

At grain filling stage, the effects of drought stress on photosynthetic acivities of photosystem I (PS I) and photosystem II (PS II) in leaves of maize (Zhengdan 21, a cultivar with high starch content) were studied by simultaneously analyzing chlorophyll a fluorescence transient and light absorbance at 820 nm. The results, obtained from two years experiments, demonstrated that the drought stress significantly reduced photosynthesis (P0.05) and grain yield (P0.05) of the maize. The K and J steps at fluorescence transient were increased by drought stress, which indicated the inhibition of oxygen-evolving complex (OEC) and electron transport chain after QA in PS II. The acceptor side of PS II was damaged more severely than the donor side of PS II. Furthermore, the maximal oxidation-reduction activity of PS I (ΔI/Io) was also significantly decreased by the drought stress, which inhibited the photosynthetic electron tranport from the PS II to PS I, destructing the coordination between PS I and PS II. We suggest that the inhibition of PS I and PS II and the destruction of the coordination between PS I and PS II by the drought stress is one of the main reasons to cause the decrease in photosyntheis and grain yield of maize.

Temperature Stress at Grain Filling Stage Mediates Expression of Three Isoform Genes Encoding Starch Branching Enzymes in Rice Endosperm

An early-maturity indica rice variety Zhefu 49, whose grain quality and starch structure are sensitive to environmental temperature, was subjected to different temperatures (32°C for high temperature and 22°C for optimum temperature) at the grain filling stage in plant growth chambers, and the different expressions of three isoform genes ( SBEI, SBEIII and SBEIV) encoding starch branching enzyme (SBE) in the endosperms were studied by the real-time fluorescence quantitative PCR (FQ-PCR) method. Effects of high temperature on the SBE expression in developing rice endosperms were isoform-dependent. High temperature significantly down-regulated the expressions of SBEI and SBEIII, while up-regulated the expression of SBEIV. Compared with SBEIV and SBEIII, the expression of SBEI gene in Zhefu 49 rice endosperms was more sensitive to temperature variation at the grain filling stage. This study indicates that changes in weather/climate conditions especially temperature stress influence rice grain formation and its quality as evidenced by isoform expression.

Physiological and Biochemical Responses to Drought during Filling Stage in Stay Green Sorghum B35

Effects of drought on a typical stay green sorghum line B35 were investigated through analyzing the physiological and biochemical characteristics of sorghum plants with the treatments of weekly drought stress starting on the 10th day and the 30th day after anthesis respectively in pot experiment.Compared with CK,the stay green sorghum B35 showed higher chlorophyll content(SPAD value),photosynthetic rate and nitrogen content in leaf,stem and grain.Under the condition of drought stress,the increments of electrical conductivity rate,malondialdehyde content in B35 were less than those in CK,the increments of proline contents and decrements of leaf water potential in B35 were more than those in CK.The activities of superoxide dismutase(SOD) and peroxydase(POD) of B35 were higher than those of CK.We suggested that the stay green sorghum line could perform the physiological autoregulation effectively at the aspects of photosynthesis,nitrogen accumulation,cell membrane permeability of leaf,osmoregulation ability and activities of protective enzymes to adapt the drought.

MEASUREMENTS OF HEAT LOSSEST DURING SOLIDIFICATION OF LIGHT MEALS

This paper describes the application of a new in-cavity thermal measurement method to determine the heat flux and calculate heat losses during high pressure die casting of aluminium A380 alloy and the magnesium alloy AZ91-D. Thermal management of the die is a critical concern in high pressure die casting and the development of microstructures after solidification. Detailed measurements were performed using infra-red probes linked to pyrometric chains and thermocouple arrays that accurately determine both casting and die surface temperatures enabling the determination of heat flux densities and interfacial heat transfer coefficients and the rapid evolution of these values with time during high pressure die casting of these alloys. The energy losses during the spray cycle can then be determined by integrating the heat flux curves for the duration of the spray application. The significance of the findings presented in this investigation arise from the uniqueness of the measurement methods applied to the determination of heat flux during the high pressure die casting of both magnesium and aluminium alloys. In particular the detailed knowledge of the thermal characteristics occurring at the cavity fill stages of the die casting process achieved through the selection of an array of fine rapid-response thermocouples integrated in one sensor along with the light pipe/pyrometric chain have enabled the accurate measurement of both the die and metal surface temperatures through the entire die casting cycle enabling the calculation of heat losses during solidification and processing.

Physiological Effects of High Temperature Stress on Grain-Setting for Guodao 6 during Flowering and Filling Stage

For a better understanding of high temperature stress on flowering and grain setting of rice during anthesis,a new rice hybrids Guodao 6 and a leading rice hybrid Xieyou 46 were selected to study the physiological and morphological adaptability to 40–42℃ of high temperature stress.The treatment was conducted with high temperature for 6 h each day from initial heading to following 15 days,and plants under natural condition was studied as control.Guodao 6 was less sensitive to high temperature stress,showing a stable yield and spikelet fertility and lower heat injury index in the stress condition.Physiologically analyzed data showed that in Guodao 6 during maturation,there were:(1) higher flag leaf photosynthetic rate and higher transform rate from light energy to chemical energy,abundant carbohydrates stored in stem and leaf-sheath as well;(2) relatively stronger physiological activity of roots,and higher leaf transpiration rate,this enhanced translocation of photo-synthate to panicle;(3) bet-ter adjustment on "Apical grain superiority",enhancing the filling of inferior spikelets.

Corn Response to Differential Removal of Leaves from the Upper and Lower Canopy

Although considerable information is available on the impact of whole-plant defoliation on the performance of corn, little is known concerning the response of corn to differential defoliation of the upper and lower canopy. The objective of this study was to determine effects of defoliation above and below the ear during grain fill on the agronomic performance of two hybrids differing in maturity. Defoliation treatments involved 50 and 100% removal of leaf tissue above and including the ear leaf, and 50 and 100% removal of leaf tissue below the ear leaf. Defoliation treatments were imposed at four grain fill stages: silking (R1), blister (R2), milk (R3), and dough (R4). Yield losses and stalk rot were greatest at R1 with 100% leaf removal above and including the ear leaf. Grain moisture at harvest was lowest in corn with complete upper canopy defoliation. Fifty and 100% defoliation of the upper canopy at silking resulted in yields 76 and 48% of the untreated check (UTC), whereas 50% and 100% defoliation of the lower canopy resulted in yields 93% and 81% of the UTC. By R4, yield losses from lower canopy defoliation were negligible (less than 5% of the UTC), whereas yield losses from upper canopy defoliation were 11% and 28% of the UTC for the 50% and 100% leaf removal treatments.

Characteristics of CO2 Exchange Rate of Flag Leaves in a Vietnamese Hybrid Rice Variety and Its Parents during Grain Filling Stage

Characteristics of CO2 Exchange Rate of Flag Leaves in a Vietnamese Hybrid Rice Variety and Its Parents during Grain Filling Stage

Effects of Nitrogen Application Rates on Accumulation, Translocation, and Partitioning of Photosynthate in Winter Wheat at Grain Filling Stage

Grain yield is mainly contributed by photosynthate post anthesis in wheat (Triticum aestivum L.), but assimilate ac- cumulation before flowering also plays an important role, especially under stress conditions. The effects of nitrogen fertilizer on assimilation and partitioning of carbohydrate at maturity have been studied in different experiments with different conclusions. To evaluate the dynamic changes of assimilation and carbohydrate partitioning in wheat organs under different nitrogen application rates, a poly-spike cultivar Yumai 49-198 and a large-spike cultivar Lankao Aizao 8 were used in a pot experiment in 2005–2006 growth season. The nitrogen fertilizer was applied (half basic application and half topdressing at jointing) at two levels of 18 g m-2 and 36 g m-2 respectively. Flag leaves were labeled by 14CO2 at pre-anthesis stage. The results indicated that the 14C assimilates photosynthesized at pre-anthesis mainly distributed in stem and sheath, next in grain at maturity. The proportion of 14C partitioned to stem and sheath, grain was 44.31–60.96% and 31.81–40.67% respectively. In comparison, the proportion of 14C partitioned to grain was increased, while to stems and sheath was reduced by increased N application. The percentage of assimilated 14C in stems and sheaths of Lankao Aizao 8 was greater than that of Yumai 49-198. There was 34.94% of the assimilates in grains de- rived from the reallocation of assimilate stored at pre-anthesis and 65.06% from photosynthate post anthesis. Moreover, transloca- tion amount, translocation proportion and contribution of assimilates before flowering to grains decreased with higher nitrogen application rate, while the contribution of assimilates post anthesis and grain weight per spike increased. The results also showed that the percentage of post anthesis assimilation to grains was 77.84% and 56.29% for Lankao Aizao 8 and Yumai 49-198, respec-tively, indicating that assimilates photosynthesized post anthesis in Lankao Aizao 8 was greater than that in Yumai 49-198. Finally, grain yield in 36 g m-2 N treatment was higher than that in 18 g m-2 N treatment. Meanwhile, increase range in grain yield of Lankao Aizao 8 both in treatments of 36 g m-2 and 18 g m-2 was greater than that of Yumai 49-198, indicating that the effect of nitrogen fertilizer on Lankao Aizao 8 was significantly greater than that of Yumai 49-198.

Cell‐wall Invertases from Rice are Differentially Expressed in Caryopsis during the Grain Filling Stage

Cell-wall invertase plays an important role in sucrose partitioning between source and sink organs in higher plants. To investigate the role of cell-wall invertases for seed development in rice (Oryza sativa L.), cDNAs of three putative cell-wall invertase genes OsCIN1, OsCIN2 and OsCIN3 were isolated. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed different expression patterns of the three genes in various rice tissues/organs. In developing caryopses, they exhibited similar temporal expression patterns, expressed highly at the early and middle grain filling stages and gradually declined to low levels afterward. However, the spatial expression patterns of them were very different, with OsCIN1 primarily expressed in the caryopsis coat, OsCIN2 in embryo and endosperm, and OsCIN3 in embryo. Further RNA in situ hybridization analysis revealed that a strong signal of OsCIN2 mRNA was detected in the vascular parenchyma surrounding the xylem of the chalazal vein and the aleurone layer, whereas OsCIN3 transcript was strongly detected in the vascular parenchyma surrounding the phloem of the chalazal vein, cross-cells, the aleurone layer and the nucellar tissue. These data indicate that the three cell-wall invertase genes play complementary/synergetic roles in assimilate unloading during the grain filling stage. In addition, the cell type-specific expression patterns of OsCIN3 in source leaf blades and anthers were also investigated, and its corresponding physiological roles were discussed.