Cone Length Research Articles

Prediction Methodology for Second-Mode-Dominated Boundary-Layer Transition in Wind Tunnels

This paper presents new methodologies based on Mack’s amplitude method to estimate the start of transition in hypersonic wind tunnels when the second mode dominates the transition process. The methodologies rely on linear stability computations, measured or modeled tunnel noise, and experimentally determined second-mode breakdown amplitude and receptivity correlations. The first technique uses the measured pitot pressure fluctuations and correlations for the receptivity coefficient to estimate the initial amplitudes. The second technique replaces pitot pressure measurements with a freestream noise spectral amplitude model based on the parameters found in Pate’s correlation. The rationale behind this new model and new insight into Pate’s correlation are provided. The methods can successfully correlate Tunnel 9 and Tunnel F cone measurements at Mach numbers between 9 and 10, unit Reynolds numbers between 1.8 and 30 million per meter, and nose-tip radii between 1.5 and 12.7 mm. The standard error between the measured and predicted start of transition is approximately 14%, which corresponds to or 4% of the cone length. In comparison, predictions based on a constant transition factor yield a standard error greater than 40% and fail to predict transition in several cases.

Free vibration of layered truncated conical shells filled with quiescent fluid using spline method

Free vibration of layered truncated conical shells filled with quiescent fluid using spline method is studied. Love’s first approximation theory is used to formulate the equations of motion of truncated conical shells. Velocity potential and Bernoulli’s equations have been applied for the expression of the pressure of the fluid. The fluid is assumed to be incompressible, inviscid and quiescent. The solutions of displacement functions are assumed in a separable form to obtain a system of coupled differential equations in terms of displacement functions. The displacement functions are approximated by Bickley-type splines to obtain the generalized eigenvalue problem by combining with boundary conditions. A generalized eigenvalue problem is obtained and solved numerically for frequency parameter and an associated eigenvector of spline coefficients. Two layered shells are considered. Parametric studies are made to investigate the effect of fluid on the frequencies with respect to the relative layer thickness, semi cone angle and length ratio.

On the linear dependence of a carbon nanofiber thermal conductivity on wall thickness

Thermal transport in carbon nanofibers (CNFs) was thoroughly investigated. In particular, individual CNFs were suspended on T-type heat nanosensors and their thermal conductivity was measured over a range of temperatures. Unexpectedly, thermal conductivity was found to be dependent on CNF wall thickness and ranging between ca. 28 and 43 W/(m⋅K). Further investigation of the CNF walls with high resolution electron microscopy allowed us to propose a tentative description of how wall structure affects phonon heat transport inside CNFs. The lower thermal conductivities, compared to other CNTs, was attributed to unique CNF wall structure. Additionally, wall thickness is related to the conducting lattice length of each constituent graphene cone and comparable to the Umklapp length. Hence, as the wall thickness and thus lattice length increases there is a higher probability for phonon scattering to the next layer.

Methodology to set up nozzle-to-substrate gap for high resolution electrohydrodynamic jet printing

Several efforts have been made for the prediction of jet diameter in electrohydrodynamic jet printing; however, not much attention has been paid to the jet length, which is the distance from the cone apex to the location where the jet is unstable and is broken into atomized droplets. In this study, we measured both the cone length and the jet length using a high-speed camera, and measured the line pattern width with an optical microscope to investigate the effects of cone length and jet length on the pattern quality. Measurements were carried out with variations in nozzle diameter, flow rate, and applied voltage. The pattern width was theoretically predicted for the case when the nozzle-to-substrate distance was more than the cone length, and smaller than the summation of the cone and jet lengths (which is the case when there is no jet breakup).

Length but not transverse diameter of the excision specimen for high-grade cervical intraepithelial neoplasia (CIN 2–3) is a predictor of pregnancy outcome

The objective of this study was to analyze the impact of cone characteristics (depth, transverse diameter, and volume) on subsequent pregnancies after the loop electrosurgical excision procedure (LEEP) for cervical intraepithelial neoplasia (CIN 2-3). Pregnancy outcomes (preterm birth, gestational age at birth, mode of delivery, and birth weight) of 501 women with singleton gestations and no previous preterm birth or history of late miscarriage, who had previously undergone a single LEEP for CIN 2-3, were retrospectively analyzed with respect to length, transverse diameter, and volume of the excision specimen. The overall incidence of preterm birth was 2.4%. The rate of preterm birth in women with length greater than 20 mm or volume greater than 2.5 cm was significantly higher than that in women with length between 15 and 19 mm (15.6 vs. 3.9%, P=0.02) or women with volume between 2.0 and 2.4 cm (5.8 vs. 1.6%, P=0.04). A linear inverse correlation (r=-0.3, P<0.001) between gestational age at birth and length, but not volume (r=0.0, P=0.9) or transverse diameter (r=0.2, P<0.0001), emerged. The mode of delivery was not affected by cone characteristics. Length, but not transverse diameter and volume, of the excised specimen seems to be related to a lower gestational age at birth. When excisions are performed under strict colposcopic guidance, with a correct modulation of cone length, the risk for preterm birth and cesarean delivery in subsequent pregnancies is not increased.

Effects of microwave irradiation by means of a horn antenna in the process of seed extraction on Scots pine (Pinus sylvestris L.) cone moisture content and seed germination energy and capacity

The paper presents the results of experiments involving the exposure of Scots pine (Pinus sylvestris L.) cones to microwave radiation. The pine cones were obtained from the Maskulinskie and Brzesko Forest Districts (both in Poland). Pine cone length, thickness, and weight were determined and found to be significantly different between the two locations. Pine cones were exposed to 2.45-GHz microwaves emitted by a horn antenna, which was either fixed or moving at a speed of 0.002 m s−1 over the cones. Total microwave emission time ranged from 30 to 441 s, depending on the test variant. The measured parameters included changes in pine cone moisture content as well as the germination capacity and viability class of the extracted seeds. It was found that pine cone moisture content decreased on average by 0.3 to 6 %, depending on the amount of microwave radiation applied. It was found that pine cone size, the amount of microwave radiation, and the distance between the cones and the horn antenna affected seed germination and viability class. In most experimental variants, the seeds were damaged by microwaves. Viable seeds (classes I and II) were obtained after 30 s of exposure to microwave radiation from a fixed horn antenna positioned at a distance of 0.04 m over the cones. The application of a moving antenna positioned 0.14 m over the cones resulted in seeds of viability classes II and III following a single microwave sweep over the seeds.

Numerical simulation of the combustion characteristics and NOx emission of a swirl burner: Influence of the structure of the burner outlet

Numerical simulations on coal combustion and NOx emissions were performed for a centrally fuel-rich pulverized-coal swirl burner. By varying cone lengths of primary air, inner secondary air and outer secondary air, the burner outlet structure effect was disclosed in detail. The new findings which can deepen the understanding of the swirl burner performance are as follows. The ignition performance and NOx reduction capacity of burner increases as primary air cone length decreases. As the inner secondary air cone length increased, ignition performance of burners becomes poor and the NOx reduction capacity increases. The ignition performance and NOx reduction capacity of burners become stronger with increases in outer secondary air cone length. Under the conditions including that (i) outer secondary air cone length is three times of the outer secondary air duct diameter, (ii) inner secondary air cone length is 50–100% of outer secondary air cone length and (iii) primary air cone length is 0mm, the burner presents an excellent performance on NOx emissions and pulverized-coal combustion characteristics with air-staging conditions.

Energy absorption characteristics and a meta-model of miniature frusta under axial impact

ABSTRACTIn this paper, crushing characteristics of small-sized conical tubes called miniature frusta under axial loading have been studied. Finite-element model is developed using non-linear explicit code LS_DYNA to investigate the non-symmetrical fold patterns as well as material and geometrical non-linearity of frusta. Numerical simulation is first validated by confirming the results using experimental test data. Effects of shell thickness, semi-epical angle of cone and frusta's length on energy absorption characteristics are then studied by carrying out a parametric study. Based on the crushing parameters of numerous examples, a simplified analytical model as a meta-model for the mean crushing force of miniature frusta is presented using a Genetic Algorithm optimization for finding the meta-model coefficients. Miniature frusta show promising behaviour in lightweight design and crash analysis as their response results in low peak force and efficient-specific energy absorption. Obtained results from the developed meta-model showed good concurrence with finite elements method (FEM) model.

Numerical optimization of flow uniformity inside an under body- oval substrate to improve emissions of IC engines

Abstract Oval substrates are widely used in automobiles to reduce the exhaust emissions in Diesel oxidation Catalyst of CI engine. Because of constraints in space and packaging Oval substrate is preferred rather than round substrate. Obtaining the flow uniformity is very challenging in oval substrate comparing with round substrate. In this present work attempts are made to optimize the inlet cone design to achieve the optimal flow uniformity with the help of CATIA V5 which is 3D design tool and CFX which is 3D CFD tool. Initially length of inlet cone and mass flow rate of exhaust stream are analysed to understand the effects of flow uniformity and pressure drop. Then short straight cones and angled cones are designed. Angled cones have been designed by two methodologies. First methodology is rotating flow inlet plane along the substrate in shorter or longer axis. Second method is shifting the flow inlet plane along the longer axis. Large improvement in flow uniformity is observed when the flow inlet plane is shifted along the direction of longer axis by 10, 20 and 30 mm away from geometrical centre. When the inlet plane is rotated again based on 30 mm shifted geometry, significant improvement at rotation angle of 20° is observed. The flow uniformity is optimum when second shift is performed based on second rotation. This present work shows that for an oval substrate flow, uniformity index can be optimized when inlet cone is angled by rotation of flow inlet plane along axis of substrate. Highlights Optimize the inlet cone design to achieve the optimal flow uniformity. Angled cones have been designed with rotating flow inlet plane along the substrate in shorter or longer axis. Large improvement in flow uniformity is observed along the direction of 10, 20 and 30 mm away from geometrical centre. Flow uniformity is optimum when second shift is performed based on second rotation.

Effects of Sintered‐Metal Cone Length on Gas‐Cyclone Classification Performance

AbstractThe gas cyclone is a classic flow device commonly used in the separation of particles from a gaseous flow stream. The gas‐cyclone classification performance is affected by the length of the porous sintered‐metal cone. Three different lengths of porous sintered‐metal cones were tested to evaluate the classification performance of a gas cyclone. Clean air was fed into the cyclone through the cone. The cone's particle cut size depended on the amount of clean air injected into the cone. In medium and long cones, a very small amount of injected clean air reduced the particle cut size, whereas in short cones, the cut size remained approximately constant and was greater than that for the traditional acrylic resin cone. In all cases, clean‐air injection reduced the powder deposition to values lower than those for acrylic resin cones. The results provide application‐based guidelines for the design and usage of sintered‐metal cones.

Identification of appropriate cone length to avoid positive cone margin in high grade cervical intraepithelial neoplasia.

ObjectiveTo identify key factors for predicting positive cone margin and appropriate cone length.MethodsWe retrospectively reviewed the margin status of patients who received conization with high grade cervical intraepithelial neoplasia, along with other factors such as patient age, parity, preoperative cytology, size of disease, type of transformation zone, and cone length from patient records. Cut-off value of cone length was analyzed in women younger than 40 years old because we design conization with minimum length especially for women who wish for future pregnancy. Cut-off value of cone length was defined as length corresponds to estimated probability of positive cone margin equal to 0.1 by logistic regression analysis with variables selected by stepwise methods.ResultsAmong 300 patients, 75 patients had positive cone margin. Multivariable analysis revealed that squamous cell carcinoma at preoperative cytology (p=0.001), 2 or more quadrant disease (p=0.011), and shorter cone length (p<0.001) were risk factors for positive cone margin. Stepwise methods identified cone length and size of lesion as important variables. With this condition, cut-off value of cone length was estimated as 15 mm in single quadrant disease and 20 mm in 2 or more quadrant disease, respectively.ConclusionWe identified the independent risk factors of positive cone margin and identified the cut-off value of cone length to avoid positive cone margin in women younger than 40 years old. Conization should be performed not only according to colposcopic findings including type of transformation zone but size of disease and cone length.

Variation in needle and cone characteristics and seed germination ability of Abies bornmuelleriana and Abies equi-trojani populations from Turkey

Turkish fir (Abies bornmuelleriana Mattf.) and Trojan fir (Abies equi-trojani (Aschers. Et Sint. Ex Boiss) Mattf.) are economically and ecologically important endemic species to Turkey. These species are also becoming increasingly popular in Europe and North America due to their suitable characteristics for use as Christmas trees coupled with their pest resistance. Provenance features, as well as needle and cone characteristics and seed germination ability, of three Turkish fir and two Trojan fir populations were studied. Provenance features (vigor score, crown score, and color) and mother tree characteristics (height class, diameter at breast height, and height) were very similar between species and among populations within species. Needles of Turkish fir were significantly (P < 0.05) longer and wider than those of Trojan fir. Turkish fir also had wider cones and a higher cone width/length ratio than Trojan fir. There were moderate, positive, and significant correlations between needle-cone characteristics and location variables (elevation, latitude, and longitude). Needle size tended to increase northwards, eastwards, and upwards along an altitudinal gradient. Cone width and the cone width/length ratio showed a weak trend of increasing northwards, while the cone width also showed a weak trend of increasing eastwards. Bract and cone length were not significantly correlated with any of the location variables. The overall mean cumulative germination percentage of Turkish fir seed (57%) was significantly higher (P < 0.05) than that of Trojan fir (36%). The natural genetic resources of both species should be conserved and managed sustainably to preserve the variation in their endemic locations because of their valuable benefits to Turkey and other countries.

The problems of cervical conization for postmenopausal patients.

Cervical conization is the definitive treatment for women of any age who have cervical intraepithelial neoplasia (CIN). However, complications of the procedure have not been fully investigated in postmenopausal patients. The aim of this retrospective study was to evaluate the results and complications of cervical conization performed on premenopausal and postmenopausal patients. This study recruited 405 patients who had undergone cervical laser conization. The median age was 36 years (range 20 to 75), and there were 361 (89.1%) premenopausal and 44 (10.9%) postmenopausal women. The length of the cone removed from the postmenopausal patients was significantly longer than the length from the premenopausal patients (17.9 ± 3.9 mm vs. 15.7 ± 3.6 mm, respectively; p = 0.02). The rate of positive endocervical cone margins from the premenopausal patients was significantly higher than the rate from the postmenopausal patients (9.1% vs. 0%, respectively; p = 0.037). The rate of cervical stenosis was significantly higher in postmenopausal patients than in premenopausal patients (59.1% vs. 8.3%; respectively; p < 0.0001). There was no difference in the rates of frequency of intraoperative complications. Although deep incision is mandatory for complete excision of CIN in postmenopausal patients, it increases the incidence of cervical stenosis. Cervical conization may be a less invasive surgical procedure for older women with CIN than hysterectomy; however, the risk of postoperative complications remains, causing a dilemma for physicians treating postmenopausal women with CIN.

On Prefabricated Stress Cone for HTS Cable Termination

The high-temperature superconducting (HTS) cable terminal has been rapidly improved in recent years. One of the hotspots in the HTS field is the prefabricated stress cone, which is widely recognized for its advanced processing technology that brings high insulation resistance and structure compactness. Aiming at designing a robust HTS terminal, an equivalent circuit model of a 35-kV prefabricated stress cone is established. Then, we concentrate on analyzing and optimizing parameters such as the stress cone length and the insulation thickness that affect the electric field distribution with ANSYS. Furthermore, a real 35-kV stress cone is constructed for an insulation performance test. The rationality and feasibility of the prefabricated stress cone design are verified.

Molecular Dynamics Simulation of the Effect of Angle Variation on Water Permeability through Hourglass-Shaped Nanopores.

Water transport through aquaporin water channels occurs extensively in cell membranes. Hourglass-shaped (biconical) pores resemble the geometry of these aquaporin channels and therefore attract much research attention. We assumed that hourglass-shaped nanopores are capable of high water permeation like biological aquaporins. In order to prove the assumption, we investigated nanoscale water transport through a model hourglass-shaped pore using molecular dynamics simulations while varying the angle of the conical entrance and the total nanopore length. The results show that a minimal departure from optimized cone angle (e.g., 9° for 30 Å case) significantly increases the osmotic permeability and that there is a non-linear relationship between permeability and the cone angle. The analysis of hydrodynamic resistance proves that the conical entrance helps to reduce the hydrodynamic entrance hindrance. Our numerical and analytical results thus confirm our initial assumption and suggest that fast water transport can be achieved by adjusting the cone angle and length of an hourglass-shaped nanopore.

Fertility and early pregnancy outcomes after conservative treatment for cervical intraepithelial neoplasia.

Cervical intra-epithelial neoplasia (CIN) typically occurs in young women of reproductive age. Although several studies have reported the impact that cervical conservative treatment may have on obstetric outcomes, there is much less evidence for fertility and early pregnancy outcomes. To assess the effect of cervical treatment for CIN (excisional or ablative) on fertility and early pregnancy outcomes. We searched in January 2015 the following databases: the Cochrane Gynaecological Cancer Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL; The Cochrane Library, Issue 12, 2014), MEDLINE (up to November week 3, 2014) and EMBASE (up to week 52, 2014). We included all studies reporting on fertility and early pregnancy outcomes (less than 24 weeks of gestation) in women with a history of CIN treatment (excisional or ablative) as compared to women that had not received treatment. Studies were classified according to the treatment method used and the fertility or early pregnancy endpoint. Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated using a random-effects model and inter-study heterogeneity was assessed with I(2). Two review authors (MK, AM) independently assessed the eligibility of retrieved papers and risk of bias. The two review authors then compared their results and any disagreements were resolved by discussion. If still unresolved, a third review author (MA) was involved until consensus was reached. Fifteen studies (2,223,592 participants - 25,008 treated and 2,198,584 untreated) that fulfilled the inclusion criteria for this review were identified from the literature search. The meta-analysis demonstrated that treatment for CIN did not adversely affect the chances of conception. The overall pregnancy rate was higher for treated (43%) versus untreated women (38%; RR 1.29, 95% CI 1.02 to 1.64; 4 studies, 38,050 participants, very low quality), although the inter-study heterogeneity was considerable (P < 0.01). The pregnancy rates in treated and untreated women with an intention to conceive (88% versus 95%, RR 0.93, 95% CI 0.80 to 1.08; 2 studies, 70 participants, very low quality) and the number of women requiring more than 12 months to conceive (14% versus 9%, RR 1.45, 95% CI 0.89 to 2.37; 3 studies, 1348 participants, very low quality) were no different. Although the total miscarriage rate (4.6% versus 2.8%, RR 1.04, 95% CI 0.90 to 1.21; 10 studies, 39,504 participants, low quality) and first trimester miscarriage rate (9.8% versus 8.4%, RR 1.16, 95% CI 0.80 to 1.69, 4 studies, 1103 participants, low quality) was similar for treated and untreated women, CIN treatment was associated with an increased risk of second trimester miscarriage, (1.6% versus 0.4%, RR 2.60, 95% CI 1.45 to 4.67; 8 studies, 2,182,268 participants, low quality). The number of ectopic pregnancies (1.6% versus 0.8%, RR 1.89, 95% CI 1.50 to 2.39; 6 studies, 38,193 participants, low quality) and terminations (12.2% versus 7.4%, RR 1.71, 95% CI 1.31 to 2.22; 7 studies, 38,208 participants, low quality) were also higher in treated women.The results should be interpreted with caution. The included studies were often small with heterogenous design. Most of these studies were retrospective and of low or very low quality (GRADE assessment) and were therefore prone to bias. Subgroup analyses for the individual treatment methods and comparison groups and analysis to stratify for the cone length was not possible. This meta-analysis suggests that treatment for CIN does not adversely affect fertility, although treatment was associated with an increased risk of miscarriage in the second trimester. These results should be interpreted with caution as the included studies were non-randomised and many were of low or very low quality and therefore at high risk of bias. Research should explore mechanisms that may explain the increase in mid-trimester miscarriage risk and stratify this impact of treatment by the length of the cone and the treatment method used.

The effect of the cyclone length on the performance of Stairmand high-efficiency cyclone

The performance parameters of a gas cyclone, viz., pressure drop and cut-off diameter, are highly sensitive to its geometry. Cyclone length strongly affects the pressure drop as well as the collection efficiency. The contribution of the present study is therefore twofold. First, the effect of variation in the cylinder as well as the cone lengths on cyclone performance parameters with respect to the standard cyclone model is examined. Second, comparison is presented among the two geometrical variables for similar increase in their lengths. The performance and the velocity field are predicted computationally on ten different test models. It has been found that increasing the cylinder length by up to 5.5 times the cyclone diameter saves about 34% in the pressure loss and enhances the collection efficiency by about 9.5%. On the other hand, increasing the cone length by up to 6.5 times the cyclone diameter shows nearly a 29% reduction in the pressure loss and about an 11% increase in collection efficiency. It is also shown that apart from optimizing the cyclone length, the designed inlet velocity of the cyclone must be considered.

Étude cas-témoin des conséquences obstétricales de la conisation

Evaluate the obstetrical outcomes in the case of women with a history of conization. Determine the role of the cone length in the obstetrical issue. Retrospective case-control study including the patients (n=39) who had undergone a conization in a university hospital between January 2002and January 2012. The obstetrical outcomes have been compared to those from a control group (n=78). Into the exposed group the obstetrical outcomes has been compared based on the cone length. Thirty-one patients delivered after a conization (39deliveries). The obstetrical outcomes have been significantly increased in the exposed group: preterm delivery before 37weeks gestation (25.6% vs 7.7%, P=0.01), before 32weeks gestation (15.4% vs 1.3%, P=0.005) and between 28weeks gestation (10.2% vs 0%, P=0.01), premature onset of labor before 32weeks gestation (12.8% vs 1.3%, P=0.01) and before 28weeks gestation (12.8% vs 0%, P=0.01) and preterm premature rupture of membranes before 37weeks gestation (20.5% vs 1.3%, P<0.001). There was no significant difference for a length cone more than 1.5cm. Our study showed that a history of conization is an obstetrical risk factor to consider in the management of a subsequent pregnancy.

Effects of the outer secondary air cone length on the combustion characteristics and NOx emissions of the swirl burner in a 0.5 MW pilot-scale facility during air-staged combustion

Cold air experiments using a centrally fuel-rich pulverized-coal swirl burner model were performed within a laboratory-scale facility to study the effects of the outer secondary air cone length on the aerodynamic fields. The divergent angle of the air jet and the size of the central recirculation zone were found to increase with increasing outer secondary air cone lengths. The 0.5 MW pilot-scale facility was also used to optimize the length of the outer secondary air cone by measuring the flue gas temperature, and O2, CO and NOx concentrations, at different cone lengths. As the cone length was varied from 0 to 49 mm, the NOx emissions rapidly fell from 778 to 458 mg/m3 (O2 6%), while the unburned carbon content in the fly ash decreased from 5.83% to 3.51%, and CO concentration decreased from 1355 mg/m3 (O2 6%) to 99 mg/m3 (O2 6%). Based on these results, the optimum length of the outer secondary air cone was determined to be 49 mm.

Unexpected cone position in 6‐hydroxydopamine‐treated dark‐adapted goldfish retina

Dopamine (DA) is an important modulator of light‐adaptation in the vertebrate retina. A known source of DA in the retina is amacrine or interplexiform cells, but another potential source is the retinal pigmented epithelium (RPE). The neurotoxin 6‐hydroxydopamine (6‐OHDA) has been used extensively to ablate DAergic retinal neurons and could be used to distinguish between neuronal and RPE sources of DA. We have, therefore, examined first the impact of 6‐OHDA on light‐induced cone contraction, a phenomenon mediated by D2 DA receptors. Under MS‐222 anesthesia, adult goldfish (C. auratus) received two 50 μg intraocular injections of 6‐OHDA on consecutive days. After 10 days, control (uninjected) or 6‐OHDA‐treated fish were placed in the light (&gt;100 lux) or in complete darkness for 1 hr and then sacrificed, eyes removed and fixed in glutaraldehyde. Retinas were then isolated, cones labeled with anti‐zrp1 (ZIRC, Eugene, OR) and cone length determined from confocal z‐stack reconstruction. In control light‐adapted retinas, cones were contracted, with a length of 55 ± 3 µm (mean ± SD), compared to cones from dark‐adapted retinas (115 ± 7 µm). In light‐adapted retinas, treated with 6‐OHDA, cones were contracted (55 ± 1 µm) but in dark‐adapted 6‐OHDA‐treated retinas cones were partially contracted (82 ± 5 µm). A previous study reported similar results and suggested that the partially contracted cone position in dark‐adapted 6‐OHDA‐treated retina indicated a role for DA in dark‐adaptation. Another possibility is that DAergic neurons damaged, but not destroyed by 6‐OHDA, have increased tonic DA release. To investigate this further, we are currently determining to what extent cone position in 6‐OHDA‐treated retinas is affected by treatment with D2 DA receptor agonists and antagonists. Funded by the NSERC.