Double-row Arrangements Research Articles

Computational Fluid Dynamics Investigation of the Spacing of the Aerodynamic Characteristics for Multiple Wingsails on Ships

Wind energy, as an inexhaustible energy source, has become a focal point in the development of new energy for ships. Sail-assisted technology, which leverages wind power, has been successfully applied to ship propulsion. The propulsion performance of sail-assisted ships is affected by the interference characteristics among multiple wingsails. To investigate interference characteristics, an arrangement scheme involving two-element wingsails and considering the relative wind direction angle was established. To obtain the inter-stage interference characteristics of wingsails, the Reynolds average N-S equation was used in the numerical simulation conducted under steady operating conditions. The results indicate that, at the relative wind angles of 30°, 90°, and 120°, the minimum horizontal spacing in a single row arrangement scheme is 1.5c. However, at relative wind angles of 90° and 120°, inter-stage interference may induce stall conditions in the wingsails. In a double-row arrangement scheme, the wake of the upstream wingsail interferes with the flow of the downstream sail at relative wind angles of 90°. An optimal propulsion performance is achieved with a horizontal spacing of 4c and a longitudinal spacing of 10c. Moreover, the interference performance of the two-element wingsails can be enhanced through a horizontal offset arrangement. This study provides a reference for the arrangement of wingsails on ships.

Numerical simulation of flow past an 8:1 oscillating rectangular cylinder at Re = 22 000

To investigate the influence of structure’s oscillatory motion on flow, the present study employs the arbitrary Lagrangian–Eulerian method in k–ω shear stress transport (SST) turbulence model to simulate the flow past an oscillating rectangular cylinder at Re= 22 000. The cylinder undergoes reciprocating sinusoidal motion at a specified frequency f e, and the frequency ratio fr (defined as the ratio of cylinder oscillation frequency f e to the stationary cylinder vortex shedding frequency f 0), ranges from 0 to 4. The results demonstrate that, in the synchronization region (0.8 ⩽ fr⩽ 1.2), the drag coefficient shows the most notable variation and reaches its maxima at fr= 1.1 and the root mean square (r.m.s.) of the lift coefficient is proportional to the square of fr (, R 2 = 0.99). Moreover, the present study compares the similarities and differences of vortex shedding morphology between stationary and oscillating cylinders. With the increase of fr, the wake vortex gradually transforms from a single-row arrangement on the wake centerline to a parallel double-row arrangement, with the main vortex modes in the wake region observed as ‘2S’, ‘P + S’, ‘2P’ and ‘C’. Furthermore, spectral analysis, including amplitude spectrum analysis and wavelet analysis, in addition to probability density function statistical methods, are employed to comprehensively understand the velocity characteristics of the wake region. The results indicate that the oscillation of the cylinder reduces the correlation of the wake velocity. Those are beneficial in understanding the interaction between turbulence and structural fluid-induced motion.

Effects of Energy Dissipation Pier Arrangements on the Hydraulic Characteristics of Segmented Pier-Type Step Energy Dissipator Structures

To make more efficient use of limited space, improve the energy dissipation effect of the step dissipator, and mitigate the effect of cavitation, we propose a segmented pier-type step dissipator structure and used a numerical simulation to study the hydraulic effects of two different arrangements of piers: a double-row arrangement and a staggered arrangement. We’ve drawn the following conclusions from our study: the segmented pier-type structure produces a large water jump at the location of the energy dissipation pier. This involves a large amount of air, promotes air-doping of the water flow in the whole section, and reduces the length of the non-air-doping zone. The staggered pier arrangement produces a better air-doping effect at the water jump and a higher air-doping concentration along the water course. The staggered arrangement also produces a better cavitation mitigation effect and is better able to stabilise the water flow; the flow velocity at the outlet is lower, so the energy dissipation effect is better. A larger positive pressure area forms at the headwater and upstream areas of the energy dissipation pier; a larger negative pressure forms at the top and backwater of the energy areas. The staggered arrangement produces a larger negative pressure; however, under various flow conditions, the difference in the energy dissipation rate between the two forms of pier arrangements is not significant. We obtained a peak energy dissipation rate of 90.04%, which represents an improved energy dissipation effect compared with the control. The step energy dissipator described here is conducive to stabilising the outlet flow, reducing cavitation damage, and improving energy dissipation. These findings provide a valuable reference for the future design of sectional pier-type step energy dissipator structures.

Research on smoke control for an underground mall fire, based on smoke barrier and mechanical smoke exhaust system

This study examines smoke spread in an underground mall fire under the composite smoke control mode of a smoke barrier and a mechanical smoke exhaust system. The objective is to optimize the selection of smoke containment and exhaust methods in an underground mall in Fuxin City, China. A Fire Dynamics Simulator was used for numerical simulation to investigate the effects of the sagging height and spacing of smoke barriers on smoke containment, as well as the effects of size, number, and arrangement of smoke vents in the mechanical smoke exhaust system on the effectiveness of smoke exhaust. The results indicated that a smoke barrier with a sagging height of 1 m and a spacing of 5 m was effective in preventing the spread of high-temperature smoke. When the sagging height of the smoke barrier increased to 1.2 m, the smoke barrier effect was comparable to that of a 1 m height barrier. Regarding the mechanical smoke exhaust system, the size of the opening area of the smoke vent had no significant effect on the smoke exhaust effect. The best smoke exhaust effect was achieved when the number of smoke vents was 12. Additionally, the double-row setting of smoke vents was more efficient than the single-row setting. Combining a smoke barrier and a mechanical smoke exhaust system can provide a more effective smoke control compared to either system alone. Comprehensively, considering the effectiveness and economy of smoke containment and exhaust, the optimal combination of smoke containment and exhaust was determined to be a smoke barrier with a sagging height of 1 m and spacing of 5 m, and a mechanical smoke exhaust system with 12 smoke vents in a double-row arrangement.

Yield of cocoa under different agroforestry systems in a dry tropical forest in western Colombia

The expansion and modernization of the cocoa area under new strategies, such as the use of adapted genetic material and the establishment of Agroforestry Systems with cocoa, under criteria of competitiveness and sustainability, require selecting sites with adequate biophysical conditions, which facilitate the optimization of resources for production. In this sense, we conducted a study in the Estación Agraria Cotové, of the Universidad Nacional de Colombia, located in a tropical dry forest life zone (TDF), at 540 meters of elevation, with an average temperature of 27 ºC, average annual precipitation annual of 1,031 mm and relative humidity less than 70 %. The yield components and productive potential of four cocoa clones, ICS 95, TSH565, CCN 51, and ICS 60, were evaluated. The cocoa clones were planted under two controlled sunlight habitats, generated by the timber species Gmelina arborea Roxb. (single-row and double-row arrangement), and two different canopy management of the cocoa plants (plagiotropic and orthotropic growth stimulus). The clones TSH 565 and CCN 51 showed the highest yields in the two harvest years. ICS 95 showed the lowest bean index. Regarding the pod index, no differences were observed between the cocoa clones. Clones TSH 565 and CCN 51 stood out as the earliest and most productive clones.

Agronomic management options to enhance adoption of maize–common bean–common bean sequential intercropping in southern Ethiopia

Achieving food security is a prime strategic goal for many developing countries where subsistence smallholder farming is dominant. It is crucial to study and improve existing cropping systems and develop novel ones for enhanced production and efficient resource use. Experiment was conducted to identify compatible density and spatial arrangement for first associated common bean (Phaseolus vulgaris L.) under maize (Zea mays L.)–common bean–common bean sequential intercropping. Factorial combination of four bean densities and three bean arrangements was tested in randomized complete block design. Greater maize yields were obtained from 25 and 50% bean densities and from single-row and within-row arrangements. Single-row arrangement at any bean density and low to moderate densities at any arrangement maintained maize performance. Density by arrangement interaction indicated that increasing bean density enhanced competitive ability and productivity of bean under double-row and within-row arrangements. Greater maize partial land equivalent ratio (LER) of 0.90 and 0.92 were obtained at lower densities of 25 and 50%, respectively, and at single-row arrangement (0.93). Interaction of density with arrangement on total LER showed that moderate densities either in single- or double-row arrangement gave higher intercrop advantages up to a maximum of 59%. Mean net benefit from intercropping exceeded those from sole maize by 30% and from bean–bean double sole crop by 16%. Net benefit among intercrops did not vary significantly and this would allow farmers to make choice depending on their crop priority and their resources such as farm size, labor and crop management techniques.

AGRONOMIC PERFORMANCE OF GRAIN SORGHUM CULTIVATED IN DOUBLE ROWS SPACE ON BRAZILIAN CERRADO

ABSTRACT The spatial arrangement of plants in the cultivation area is a factor that directly influences grain yield, since the best arrangement can result in the greater use of water, light and nutrients. The aim of the study was to evaluate the agronomic performance of sorghum sown in double row spacing in the Brazilian Cerrado. For this purpose, field experiments were conducted in the 2018 and 2019 seasons in a complete block design with a factorial scheme of 2 x 5. There were four replications, using two row spacing: traditional (0.50 m) and double rows (0.25 m/0.75 m) and five plant populations: 120, 180 (recommended), 240, 300 and 360 thousand, plants ha-1. Morphological characteristics, yield components and grain yield were evaluated using joint data analysis for the two years of study. In 2018, due to lower rainfall during the crop season, the use of a double row arrangement presented grain yield lower than traditional spacing. On the other hand, in 2019, the year with the best water distribution, the yield was superior to that of 2018. The increase in plant population per hectare increased the yield of sorghum grains, with gains of up to 24% in relation to the recommended population of 180 thousand plants ha-1, demonstrated that the densification in this crop can be a promising technique as long as its cost/benefit is considered.

Dynamics of eucalypt clones canopy and Brachiaria brizantha production in silvopastoral systems with different spatial arrangements

The aim of this study was to relate tree planting spatial arrangements of five eucalypt clones in silvopastoral systems to brachiaria production. Tree layouts were (2 × 2) + 10 m and (3 × 3) + 9 m (double-rows) and 9 × 3 m (single-row) planting arrangements. Tree leaf area index (LAI) was measured acrosss the interrow at 38, 50, and 62 months after planting. Tree crown radius was measured at 45° intervals around the stem at 38 months. Brachiaria was sampled across the interrow at 50 months. The LAI decreased with tree density for most clones and ages. The clones GG100, 58, and 62 presented the lowest LAI, independently of age and planting arrangements. LAI decreased from the tree row to the middle of the interrow, mainly for the double-row arrangements. There was positive correlation between crown radius and area per tree, except for the clone 02, and negative with LAI for the clone 19. The highest brachiaria production was obtained in the arrangements 9 × 3 m (clones GG100 and 62) and (3 × 3) + 9 m (clone 62). Brachiaria production varied across the interrow for clone 58 in the (2 × 2) + 10 m arrangement and for the clone 62 in the double-row arrangements. LAI was not significantly correlated with brachiaria production for the tree planting spatial arrangements and the genotypes studied. Further studies should include larger distances between hedgerows to allow greater resources availability differences across the interrow.

Effect of row arrangement, age of tiller seedling and number of tiller seedlings per hill on performance of transplant aman rice

The experiment was conducted to observe the effect of row arrangement, age of tiller seedlings and number of tiller seedlings hill-1 on the vegetative characters, yield and yield contributing characters of transplant aman rice. The experiment consisted of three levels of row arrangement viz. single row (row spacing 25cm), double row (row spacing 25-10-25cm)and triple row (row spacing 25-10-10-25cm), two types of tiller seedlings viz. 25 days and 35 days old; and three levels of number of tiller seedling hill-1 viz. 2, 4 and 6 seedlings hill-1. The experiment was laid out in a three factor Randomized Complete Block Design with three replications. The highest plant height, number of effective tillers hill-1, effectivity index of tillers, number of grains panicle-1 and harvest index were found in single row arrangement compared to double and triple row arrangements but number of total spikelets panicle-1 and grain yield were highest in double row arrangement. The highest number of non-bearing tillers hill-1, number of total tillers hill-1 and number of sterile spikelets panicle-1 were found in triple row arrangement compared to single and double row arrangements. The highest plant height, effectivity index of tillers, number of grains panicle-1, grain yield, harvest index and sterility percentage were found by transplanting 25-day old tiller seedlings. Number of total tillers hill-1, non-bearing tillers hill-1, straw yield and sterility percentage were highest by transplanting 35-day old tiller seedlings. Plant height, harvest index, grain yield and panicle length were highest when 2 tiller seedlings were transplanted hill-1. Number of total tillers hill-1 and number of non-bearing tillers hill-1 were highest when 6 tiller seedlings were transplanted hill-1.Transplanting in single and double row arrangements emerged out as a promising practice. This practice improved yield of transplant aman rice. Twenty five day old tiller seedlings was found to be suitable in respect of grain yield and 2 tiller seedlings hill-1 appeared to be enough for the cultivation of transplant aman rice. Key words: Row arrangement; tiller seedling; transplant aman riceDOI: http://dx.doi.org/10.4038/jas.v6i2.3860 The Journal of Agricultural Sciences, 2011, vol .6, no 2, pp59-68

Effect of inter-row spacing with double row arrangement on yield and yield component of tomato (Lycopersicon esculuntum Mill.) at Adami Tulu Agricultural Research Center (Central Rift Valley of Oromia, Ethiopia)

The effect of inter- row spacing with double row arrangement on yield and yield components of tomato (Lycopersicon esculuntum Mill.) was conducted at Adami Tulu agricultural research center, Ethiopia, during the season of 2007 and 2008 using irrigation. The experiment was conducted to determine the optimum inter-row spacing for tomato production with double row arrangement, using randomized complete block design (RCBD) with 4 replications. Area occupied by a single plot was 4 m × 3 m with spacing of 1.5 m × 1 m between block and plot, respectively. There were a total of 5 treatments (inter- row spacing). The analyzed result at α = 0.05 indicated that ,there was no significance difference among treatments (100 × 30, 60 × 30, 50 × 30, 40 × 30 and 30 × 30 cm) between row and plant, respectively for marketable yield. Even though marketable yield showed no significance difference, 40 × 30 cm gave higher marketable yield (607.9 q/ha) followed by 60 × 30 cm and 50 × 30 cm (570.4 q/ha and 568 q/ha, respectively). From the treatments 100 x 30 cm inter -row spacing showed the least marketable yield (475.85 q/ha) as compared with the rest 4 treatments. Key words: Marketable, spacing, tomato, unmarketable, yield.

Biomechanical Advantages of Triple-Loaded Suture Anchors Compared With Double-Row Rotator Cuff Repairs

To evaluate the strength and suture-tendon interface security of various suture anchors triply and doubly loaded with ultrahigh-molecular weight polyethylene-containing sutures and to evaluate the relative effectiveness of placing these anchors in a single-row or double-row arrangement by cyclic loading and then destructive testing. The infraspinatus muscle was reattached to the original humeral footprint by use of 1 of 5 different repair patterns in 40 bovine shoulders. Two single-row repairs and three double-row repairs were tested. High-strength sutures were used for all repairs. Five groups were studied: group 1, 2 triple-loaded screw suture anchors in a single row with simple stitches; group 2, 2 triple-loaded screw anchors in a single row with simple stitches over a fourth suture passed perpendicularly ("rip-stop" stitch); group 3, 2 medial and 2 lateral screw anchors with a single vertical mattress stitch passed from the medial anchors and 2 simple stitches passed from the lateral anchors; group 4, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors capturing the medial sutures in a "crisscross" spanning stitch; and group 5, 2 medial double-loaded screw anchors tied in 2 mattress stitches and 2 push-in lateral anchors creating a "suture-bridge" stitch. The specimens were cycled between 10 and 180 N at 1.0 Hz for 3,500 cycles or until failure. Endpoints were cyclic loading displacement (5 and 10 mm), total displacement, and ultimate failure load. A single row of triply loaded anchors was more resistant to stretching to a 5- and 10-mm gap than the double-row repairs with or without the addition of a rip-stop suture (P < .05). The addition of a rip-stop stitch made the repair more resistant to gap formation than a double row repair (P < .05). The crisscross double row created by 2 medial double-loaded suture anchors and 2 lateral push-in anchors stretched more than any other group (P < .05). Double-row repairs with either crossing sutures or 4 separate anchor points were more likely to fail (5- or 10-mm gap) than a single-row repair loaded with 3 simple sutures. The triple-loaded anchors with ultrahigh-molecular weight polyethylene-containing sutures placed in a single row were more resistant to stretching than the double-row groups.

Effects of micro-ramps on a shock wave/turbulent boundary layer interaction

Stereoscopic particle image velocimetry is used to investigate the effects of micro-ramp sub-boundary layer vortex generators, on an incident shock wave/boundary layer interaction at Mach 1.84. Single- and double-row arrangements of micro-ramps are considered. The micro-ramps have a height of 20% of the unperturbed boundary layer thickness and the measurement planes are located 0.1 and 0.6 boundary layer thicknesses from the wall. The micro-ramps generate packets of individual vortex pairs downstream of their vertices, which produce counter-rotating longitudinal streamwise vortex pairs in a time-averaged view. These structures induce a pronounced spanwise variation of the flow properties, namely the mixing across the boundary layer interface. The probability of reversed-flow occurrence is decreased by 20 and 30% for the single- and double-row configurations, respectively. Both configurations of micro-ramps stabilize the shock motion by reducing the length of its motion by about 20% in the lower measurement plane. The results are summarized by a conceptual model describing the boundary layer’s and interaction’s flow pattern under the effect of the micro-ramps.

Study on the analogy feedback active soft edge noise barrier

It is feasible to enhance the effect of reduction of the noise barrier on low frequency noise using the active control system. On the basis of the forerunners’ research, an analogy feedback active control system that is easy to be carried out was arranged on the top of a noise barrier to form an analogy feedback active soft edge noise barrier in order to enhance the effect of reduction of the noise barrier on low frequency noise. Through a preliminary experimental study, this method was proved to be feasible and the following preliminary conclusions on the arrangement of active control systems were made: (1) when control sources were arranged in a single row, the control effect was determined by the density of arrangement: the higher the density, the better the control effect; (2) with the same density of arrangement, the control effect of the double row arrangement was better than that of the single row arrangement; (3) with the same number of control sources, the single row arrangement had better control effect than the double row arrangement.

Cultivar and Plant Arrangement Effects on Yield and Fruit Quality of Bell Pepper

Single- and double-row arrangements of a fixed population (one plant every 0.285 m2) were compared in factorial combination with two (2002) or five (2003) cultivars for effects on yield and fruit quality of bell pepper (Capsicum annuum L.). Arrangements for 2002 were S30, single rows 0.95 m apart, plants within rows 30 cm apart; D30, 1.9 m between centers of double-row beds, double rows 30 cm apart on beds, plants within rows 30 cm apart; S37.5, single rows 0.76 m apart, plants within rows 37.5 cm apart; and D37.5, 1.52 m between centers of double-row beds, double rows 24 cm apart on beds, plants within rows 37.5 cm apart. Only the S30 and D30 arrangements were used in 2003 after 2002 results showed almost no differences between S30 and S37.5 or between D30 and D37.5. Choice of cultivar was more critical in Texas, where `X3R Wizard' consistently outperformed `King Arthur', than in Oklahoma. Single rows resulted in more full-season total marketable fruit weight than double rows in three experiments out of four, primarily as a result of an increased weight of U.S. No. 1 fruit with single rows. Average weight per marketable fruit was consistently unaffected by plant arrangement. Single rows also resulted in a greater full-season weight of sunburned fruit than double rows in two experiments out of four. Cultivar × plant arrangement interactions were not evident in Oklahoma and never involved full-season marketable fruit weights at either location in either year. Given the tested population, a single-row arrangement is likely to result in increased full-season production of U.S. No. 1 bell pepper fruit compared with a double-row arrangement, despite an increased potential for sunburned fruit with single rows.

Ways to increase endurance of the refractory lining in converters

Based on the expertise gained in the use of a 350-ton converter at the WSIWS Joint-Stock Co., blowing facilities and regimes have been modified. Low-temperature slag splashing is numerically simulated for a top-blown tuyere using tips with single and double-row nozzle arrangement. A slag-splashing tuyere fitted with a steel tip with a double-row arrangement of nozzles has been designed. Ways to improve the melting technology using modified tuyeres combining slag splashing and flame gunning operations and to improve repair of the lining using a vertical tuyere are proposed.

Plant Arrangement and Cultivar Effects on Yield and Fruit Quality of Bell Pepper

Single- and double-row arrangements of a fixed population (one plant every 0.285 m2) were compared in factorial combination with two (2002) or five (2003) cultivars for effects on yield and fruit quality of bell pepper (Capsicum annuum L.). Arrangements for 2002 were: (1) 1.9 m between centers of double-row beds, rows on beds 30 cm apart, plants within rows 30 cm apart; (2) single rows 0.95 m apart, plants within rows 30 cm apart; (3) 1.52 m between centers of double-row beds, rows on beds 24 cm apart, plants within rows 37.5 cm apart; and (4) single rows 0.76 m apart, plants within rows 37.5 cm apart. Only arrangements (1) and (2) were used in 2003. Row arrangement did not affect marketable fruit production in Oklahoma in 2002, but single rows resulted in a greater weight of fruit with blossom-end rot than double rows. Arrangement (2) resulted in both a greater weight of U.S. No. 1 fruit and a greater weight of sunburned fruit than arrangement (1) in Texas in 2002. `King Arthur' produced more marketable fruit than `X3R Wizard' in Oklahoma in 2002, but the opposite occurred in Texas. Arrangement (2) resulted in a greater weight of U.S. No. 1 fruit than arrangement (1) in both locations in 2003. Arrangement (2) also resulted in greater weights of sunburned (Oklahoma) or total cull (Texas) fruit than arrangement (1) in 2003. `Lafayette' and `X3R Wizard' produced a greater weight of marketable fruit than `Boynton Bell', `Karma', and `King Arthur' in Texas in 2003, but not in Oklahoma. Plant arrangement × cultivar interactions were not evident in Oklahoma and minimal in Texas. Given the tested population, a single row arrangement is likely to result in higher U.S. No. 1 fruit yields than a double-row arrangement, despite an increased potential for cull fruit production with single rows.

Effects of Bed Width, Planting Arrangement, and Plant Population on Seed Yield of Pinto Bean Cultivars with Different Growth Habits

In the arid western USA, irrigated dry edible beans (Phaseolus vulgaris L.) are normally planted in single drill rows placed on seed beds that vary from 22 to 30 in. in width. Bed width is usually selected to accomodate the producers' farm equipment and production practices. There is a need to reevaluate planting practices for pinto beans because new cultivars have recently been released that exhibit different growth habits. Field research was conducted at Ft. Collins and Fruita, CO, in 1989 and 1990 to evalatue the influences of bed width (narrow vs. wide), number of drill rows planted on a bed (one vs. two), and plant populations (72 000 vs. 100 000 plants/acre) on yield and yield components of three pinto bean cultivars that have Type I (determinate bush), Type II (indeterminate upright), and Type III (indeterminate vine) growth habits. Cultivars differed in mean seed yield across treatments but did not interact with planting arrangements or populations, indicating that the cultivars responded similarly to altered planting arrangements. Mean seed yield among cultivars was higher in narrow than in wide beds at both locations. Double row arrangement on beds produced higher seed yield at Ft. Collins in both years, but did not influence seed yield at Fruita. Among yield components, pod number most affected seed yield at both locations in both years. Plant population did not influence seed yield in either location or year. In general, seed yield was increased by planting on narrow beds or when double drill rows were planted on beds. These results suggest that pinto bean producers should be able to increase production by planting the crop in either a double row arangement on 30 in. beds, or in single rows on beds less than 30 in. in width.

Plant population studies on peanut (Arachis hypogaea L.) in subtropical Australia. 1. Growth under fully irrigated conditions

Effects of plant density and spatial arrangement on growth and yield responses of 4 peanut cultivars were examined under fully irrigated conditions at Kingaroy, south-eastern Queensland (26�33'S., 151�50'E.). Cultivars represented either the Spanish or Virginia botanical type. Spanish cultivars had either very early (Chico) or early (McCubbin) maturity, while Virginia cultivars had either medium (Early Bunch) or very late (Mani Pintar) maturity. The interaction of plant density (44 000-376 000 plants/ha) with sowing date was assessed in 3 sowings in 1984-85 (S1, 1 November; S2, 5 December; S3, 15 January), with a further sowing in 1985-86 (S4, 21 November). The interaction of plant density and spatial arrangement was assessed in 1985-86. Total dry matter (TDM) and pod yields showed highly significant (P&lt;0.01) linear and quadratic responses to increasing plant density. Cultivars differed in their response to density. McCubbin, Early Bunch and Mani Pintar showed no responses to increased density above 88 000 plants/ha, while maximum TDM and pod yields of Chico were recorded at 352 000 plants/ha. Sowing date had no significant effect on the response of any cultivar to plant density. However, all cultivars except Chico produced significantly less TDM and pod yield in S3, due to cool temperatures and/or frosts terminating growth. A 1 : 1 (square) planting arrangement produced significantly greater pod yields and more TDM than the conventional commercial practice of rows 90 cm apart. Planting in a double-row arrangement (20 cm between 2 rows) based on 90 cm centres produced intermediate pod and TDM yields. A simple model was used to describe the effects of plant density and sowing date on yield, and proved useful for highlighting differences among cultivars and sowing dates. A limitation of the model was a tendency to overestimate pod yield at low plant density in Spanish cultivars, where the harvest index declined at very low plant densities.

The influence of photoperiod and plant density on yield of winter-grown gladioli in Queensland

The yields of inflorescences, corms and cormlets, and the inflorescence quality of winter-grown gladioli in south-east Queensland, were studied under 2 daylength regimes, 3 plant densities (150 000, 300 000 and 450 000 corms ha −1) and 3 plant arrangements (bed, double row and single row). The daylength treatments were the natural daylength (12.3–14.5 hours) and a 24-hour photoperiod treatment in which natural daylengths were extended using incandescent light of an intensity of 150 lux. Two cultivars were used. Extending the photoperiod to 24 hours delayed flowering by approximately 15 days, and increased the number of inflorescences harvested from low, medium and high density treatments by 20, 91 and 169%, respectively, when compared to the inflorescence yield from these density treatments under natural daylengths. The quality of the inflorescences from the high-density treatment receiving the 24-hour photoperiod was similar or superior in all quality characteristics to that of inflorescences grown under the most favourable density treatment under natural daylengths (150 000 corm ha −1). Plant arrangement had little effect on the number of days to flowering or inflorescence yield but inflorescence quality was improved when plants were grown in a double-row arrangement compared to those from the bed or single-row arrangements. Extension of the photoperiod had no effect on the number of new corms per plot. However, the average weight of new corms and the weight of cormlets per plot and per corm were reduced by approximately 32, 71 and 63%, respectively, when compared to the results obtained from plants grown under natural daylengths. These results suggest that flowers compete for available photosynthates with corms and cormlet development. The economic feasibility of extending photoperiod for the commercial production of winter-grown gladioli in south-east Queensland is discussed.

Nesting of a single shape on a strip

This paper presents three approaches to minimize and eliminate scrap from stamping a single shape arranged in a single row or double rows on strip raw materials. In the first approach, interlocking shapes are generated. Although such shapes are scrap-free, they require congruent lines in the design. At the early stages of the design process, a skilful designer can compromise between functional features and symmetric features to improve nesting. The second approach is to characterize a shape by parallel lines bounding it. Specifically, the method to find a minimum area parallelogram that encloses a given convex shape is discussed. The result gives the optimum arrangement of a convex shape in single row. The third approach involves the nesting of a given shape in a specified pattern. Three computational algorithms for the single and double row arrangements are given. The double row arrangement includes a half-turn or a mirror reflection. The three approaches are all based on the concept of interlocking shap...