Wide Cone Research Articles

Wide cone beam CT dosimetry: Analysis of results and uncertainty evaluation

ObjectiveTo investigate the consistency of the recommended methodology, we analyzed the dosimetric results obtained for each setup beam shaping filter and tube voltage and evaluated the uncertainty associated with the full dose measurement process. MethodsA 300-mm PTIC was used to validate the results obtained with the 100-mm PTIC. Considering the other dosimetric parts, a cylindrical 160-mm diameter PMMA phantom and a cylindrical 320-mm diameter PMMA phantom were also used in the experimental protocol. ResultsFor the lowest and highest tube voltages available, the CTDIair,160 values obtained by 1-step dosimetry with the 300-mm PTIC were greater than the respective values obtained by 2- and 3-step dosimetry with the 100-mm PTIC. ConclusionThis study established that careful positioning of the 100-mm PTIC in 2 or 3 steps, as well as proper execution of the other dosimetric parts recommended by the IAEA, represents a validated approach within up to 20% uncertainty for wide cone beam CT dosimetry.

Integrative description of two new species of the genus Mesobiotus (Eutardigrada, Macrobiotoidea) from Russia, with an updated phylogeny of the genus

In this study, we describe two new species of Mesobiotus based on morphological data collected through light and scanning electron microscopy. Descriptions include DNA sequences of four commonly used molecular markers (18S rDNA, 28S rDNA, ITS-2, and COI). Mesobiotus efa sp. nov. was discovered in North-West Russia and belongs to the group of species with smooth cuticle, harmsworthi-type OCA, typical Mesobiotus claws IV with unindented lunules, and egg chorion with reticulated processes in form of ‘sharp wide cones’ or ‘cones with long slender endings’, egg process bases with well-developed crone of dark thickenings without finger-like projections, and egg shell surface between the processes with ridges without reticulation, areolation or semi-areolation. It can be distinguished from all know species of this group by a unique combination of morphological and morphometric characters. Mesobiotus vulpinus sp. nov. was found in the Russian Far East, and is similar to Mesobiotus mauccii by having an egg chorion with polygonal relief. The new species can be distinguished from M. mauccii by having a narrower buccal tube, by details of oral cavity armature, and by longer egg chorion processes. Furthermore, we provide results of the phylogenetic analyses of the genus Mesobiotus conducted in this study.

Effect of scatter suppression with 2D antiscatter grids in photon counting compact CBCT.

Energy sensitive and photon counting detectors can provide improved tissue visualization and material quantification capabilities in Cone Beam Computed Tomography (CBCT) systems. However, their implementation in CBCT systems is more challenging, which is in part due to high fluence of scattered X-rays in wide cone angle CBCT geometry. Specifically, high scatter contamination in lower energy spectrum challenges reconstruction of high fidelity CBCT images by using lower energy X-rays. To address this problem, we investigated a robust scatter rejection with 2D antiscatter grids in a benchtop photon counting and compact CBCT system. The benchtop system employs a 35 cm wide CdTe photon counting detector with two energy thresholds. To reject scatter, a dedicated 2D antiscatter grid (2D grid) prototype made from tungsten was developed and mounted directly on the detector. To correct residual scatter not stopped by the 2D grid, a measurement-based scatter correction method, referred to as Grid-based Scatter Sampling (GSS), was utilized. Without 2D grid, scatter to primary ratio (SPR) reached 2.3 in the 15-40 keV energy bin. SPR was factor of 3 higher in the lowest energy bin when compared to the highest energy bin (90-120 keV). With the 2D grid, SPR was reduced below 0.14, and SPR values were more homogenous across the energy spectrum. CT number nonuniformity was factor of 3 lower in both low and high energy bin CBCT reconstructions. Improvement in contrast to noise ratio and contrast was more pronounced in the low energy bin CBCT images. This work indicates that 2D grids can significantly reduce spectral contamination caused by scatter in photon counting compact CBCT, and potentially enable higher fidelity CBCT image reconstructions.

Effect of Seed Extraction Period and Germination Temperature on Viability of Pinus patula Under Controlled Conditions

A number of coniferous species have demonstrated varied cone responses to the temperature intensities for seed release and subsequent seed germination behaviour. This study investigated the interactions of cone physical characteristics (weight and width), exposure duration (6,12 and 24 hours) at a fixed extraction temperature (65°C) and the germination temperature (22, 27 and 32°C) on seed quality of Pinus patula. The experimental design was a factorial experiment (4×3×3) laid down in a completely randomized design (CRD), with thirty-six treatments replicated 3 times. Analysis of the difference in means from the three factor effects from ANOVA was performed using R Statistical software. Where significant differences were observed, post hoc tests were carried out to separate means using the Tukey test at 5 % significance level. Results showed significant (p=0.001) differences in germination performance as a result of cone characteristics, extraction exposure periods, and germination chamber conditions. Seeds extracted from heavy cones and exposed to germination temperature of 32℃ demonstrated the highest germination percent at 90% while the lowest was 20% from light cones exposed to similar germination temperature conditions. Negative and significant correlation coefficients were observed in germination of seeds from narrow and light cones, thus cone sorting for heavy and wide cones was recommended for better germination performance of P. patula seed germplasm.

Origin of the super-resolution of microsphere-assisted imaging

Theoretical explanation of the super-resolution imaging by contact microspheres created a point of attraction for nanoimaging research during the last decade with many models proposed, yet its origin remains largely elusive. Using a classical double slit object, the key factors responsible for this effect are identified by an ab initio imaging model comprising object illumination, wave scattering, and image reconstruction from the diffracted far fields. The scattering is found by a full-wave solution of the Maxwell equations. The formation of super-resolved images relies on coherent effects, including the light scattering into the waves circulating inside the microsphere and their re-illumination of the object. Achieving the super-resolution of the double slit requires a wide illumination cone as well as a deeply sub-wavelength object-to-microsphere separation. The resultant image has a significantly better resolution as compared to that from the incoherent imaging theory.

Wide-Baseline Light Fields using Ellipsoidal Mirrors.

Traditional hand-held light field cameras only observe a small fraction of the cone of light emitted by a scene point. As a consequence, the study of interesting angular effects like iridescence are beyond the scope of such cameras. This paper envisions a new design for sensing light fields with wide baselines, so as to sense a significantly larger fraction of the cone of light emitted by scene points. Our system achieves this by imaging the scene, indirectly, through an ellipsoidal mirror. We show that an ellipsoidal mirror maps a wide cone of light from locations near one of its foci to a narrower cone at its other focus; thus, by placing a conventional light field camera at a focus, we can observe a wide-baseline light field from the scene near the other focus. We show via simulations and a lab prototype that wide-baseline light fields excel in the traditional applications involving changes in focus and perspective. Additionally, the larger cone of light that they observe allows the study of iridescence and thin-film interference. Perhaps surprisingly, the larger cone of light allows us to estimate surface normals of scene points by reasoning about their visibility.

Implementation and evaluation of the AAPM TG 111 for radiation dosimetry in a state-of-the-art C-arm cone beam CT system

The aim of this study was to assess the dosimetric characteristics of a state-of-the-art C-arm cone beam computed tomography (CBCT) system using the methodology proposed by the American Association of Physicists in Medicine (AAPM) Task Group (TG) 111. The dose measurement methodology described in AAPM TG 111 for wide cone beam acquisitions without table translation was employed to estimate equilibrium beam length () and equilibrium dose () in various interventional task-specific protocols with different tube arc projection geometries. Dose profiles were derived from point dose measurements in the centre and peripheral locations of the ICRU/AAPM and standard polymethyl methacrylate (PMMA) body phantom. Dose measurements were performed in phantom and free-in-air using a solid-state point detector. Monte Carlo (MC) based simulation dosimetry was performed to quantify the inhomogeneous dose patterns imparted in the phantoms. Estimated and on the ICRU/AAPM phantom was up to 49.4 cm and 6.17 mGy/100 mAs, respectively. Corresponding values determined on the PMMA phantom were 139 cm and 8.8 mGy/100 mAs, respectively. Free-in-air dose measurement ranged from 1.43 mGy/100 mAs to 5.93 mGy/100 mAs. Per cent difference in and between MC simulation and solid-state point detector measurement methods in the ICRU/AAPM phantom were within 16% and 18%, respectively. Manufacturers can use the presented methodology to characterize the dosimetric properties of C-arm CBCT systems. Clinical medical physicists may follow this methodology to verify corresponding data provided by the manufacturer and check for C-arm CBCT system performance dosimetric consistency.

Evaluation of the feasibility of a multisource CBCT for maxillofacial imaging

Objective. The aim of this study was to investigate the feasibility of improving the image quality and accuracy of cone beam computed tomography (CBCT) by replacing the conventional wide cone angle x-ray tube with a distributed x-ray source array positioned in the axial direction. Approach. The multisource CBCT (ms-CBCT) design was experimentally simulated using a benchtop scanner with a carbon nanotube x-ray tube and a flat-panel detector. The source was collimated and translated in the axial direction to simulate a source array with a reduced cone angle for each beam. An adjacent scatter ratio subtraction (ASRS) method was implemented for residual scatter reduction. Several phantoms were imaged using the ms-CBCT and conventional CBCT configurations under otherwise similar conditions. The Requirements of the ms-CBCT design on the x-ray source and detector were evaluated. Main results. Compared to the conventional CBCT, the ms-CBCT design with 8 sources and ASRS significantly improved the image quality and accuracy, including: (1) reducing the cupping artifact from 15% to 3.5%; (2) reducing the spatial nonuniformity of the CT Hounsfield unit values from 38.0 to 9.2; (3) improving the contrast-to-noise ratio of the low contrast objects (acrylic and low density polyethylene inserts) against the water-equivalent background by ∼20% and (4) reducing the root-mean-square error of the HU values by 70%, from 420.1 to 124.4. The imaging dose and scanning time used by the current clinical CBCT for maxillofacial imaging can be achieved by current source and detector technologies. Significance. The ms-CBCT design significantly reduces the scatter and improves the image quality and accuracy compared to the conventional CBCT.

Implant-Abutment Connections and Their Effect on Implant Survival Rates and Changes in Marginal Bone Levels (Δ): A Systematic Review and Meta-Analysis of 45,347 Oral Implants.

Purpose: To quantify the cumulative oral implant survival rates and changes in radiographic bone levels based on the configuration of the implant-abutment connection type over time. Materials and Methods: An electronic literature search was conducted in four databases (PubMed/MEDLINE, Cochrane Library, Web of Science, and Embase), and records were refereed by two independent reviewers based on the inclusion criteria. Data from included articles were grouped by implant-abutment connection type into four categories ([1] external hex; [2] bone level, internal, narrow cone < 45 degrees; [3] bone level, internal wide cone ≥ 45 degrees or flat; and [4] tissue level) and duration of follow-up (short-term 1 to 2 years, mid-term 2 to 5 years, and long-term > 5 years). Meta-analyses were performed for cumulative survival rate (CSR) and changes in marginal bone level (ΔMBL) from baseline (loading) to last reported follow-up. Studies were split or merged as appropriate based on the implants and follow-up duration in the study and trial design. The study was compiled under PRISMA 2020 guidelines and registered in the PROSPERO database. Results: A total of 3,082 articles were screened. Full-text review of 465 articles resulted in a total of 270 articles (representing 16,448 subjects with 45,347 implants) included for quantitative synthesis and analysis. Mean ΔMBL (95% CI) was as follows: short-term external hex = 0.68 mm (0.57, 0.79); short-term bone level, internal, narrow cone < 45 degrees = 0.34 mm (0.25, 0.43); short-term bone level, internal wide cone ≥ 45 degrees = 0.63 mm (0.52, 0.74); short-term tissue level = 0.42 mm (0.27, 0.56); mid-term external hex = 1.03 mm (0.72, 1.34); mid-term bone level, internal, narrow cone < 45 degrees = 0.45 mm (0.34, 0.56); mid-term bone level, internal wide cone ≥ 45 degrees = 0.73 mm (0.58, 0.88); mid-term tissue level = 0.4 mm (0.21, 0.61); long-term external hex = 0.98 mm, 0.70, 1.25); long-term bone level, internal, narrow cone < 45 degrees = 0.44 mm (0.31, 0.57); long-term bone level, internal wide cone ≥ 45 degrees = 0.95 mm (0.68, 1.22); and long-term tissue level = 0.43 mm (0.24, 0.61). CSRs (95% CI) were: short-term external hex = 97% (96%, 98%); short-term bone level, internal, narrow cone < 45 degrees = 99% (99%, 99%); short-term bone level, internal wide cone ≥ 45 degrees = 98% (98%, 99%); short-term tissue level = 99% (98%, 100%); mid-term external hex = 97% (96%, 98%); mid-term bone level, internal, narrow cone < 45 degrees = 98% (98%, 99%); mid-term bone level, internal wide cone ≥ 45 degrees = 99% (98%, 99%); mid-term tissue level = 98% (97%, 99%); long-term external hex = 96% (95%, 98%); long-term bone level, internal, narrow cone < 45 degrees = 98% (98%, 99%); long-term bone level, internal wide cone ≥ 45 degrees = 99% (98%, 100%); and long-term tissue level = 99% (98%, 100%). Conclusion: The configuration of the implant-abutment interface has a measurable effect on the ΔMBL over time. These changes can be observed over a period of at least 3 to 5 years. At all measured time intervals, similar ΔMBL was noted for external hex and internal wide cone ≥ 45-degree connections, as were internal, narrow cone < 45-degree and tissue-level connections.

Influence of Cone Physical Characteristics and Extraction Exposure Period on Seed Yield of Pinus patula

This study examines the correlation between extraction exposure periods and cone physical characteristics on Pinus patula seed yield. Systematic random sampling was employed for tree identification in an even-aged clonal seed orchard, and the laboratory phase was laid down as a factorial experiment with two factors: cone physical characteristics and extraction exposure period at three levels. Seed counts were taken for cones categorized as; heavy, light, narrow, and wide at three extraction exposure periods 6 hours, 12 hours, and 24 hours in a constant oven temperature of 65°C. The experiment had 12 (L1,H1,N1,W1,L2,H2,N2,W2,L3,H3,N3,W3)treatments with 60 cones per treatment. The time spent counting and returning cones during the inter-stage observation ranged from 10 to 15 minutes. Data collected were tabulated and means analyzed using ANOVA with results generated as per the objectives. The number of seeds released within the hours of exposure was captured as the seed extraction rate. The first six hours yielded the optimum number of seeds per cone with the mean highest number of seeds from wide cones. The lowest mean number of seeds released observed was 28, from light cones, while the highest mean number of seeds was observed to be 56 from wide cones. Cone sorting based on size before extraction is recommended for optimized seed yield. The stages of seed extraction employed here can be used in mechanized seed extraction cabinets equipped with timers at controlled temperatures.

Projection-type electron spectroscopy collimator analyzer for charged particles and x-ray detections.

We developed a compact sized device for angular and energy analysis of charged particles in a wide acceptance cone angle of nearly 1π steradian. This device is configured from an electrostatic lens comprising an axisymmetric aspherical mesh, which has a concave shape viewed from the point source, a set of axisymmetric electrodes, planar grids, microchannel plates, and a fluorescent screen positioned coaxially. The potentials of electrodes are adjusted so that the trajectories of the electrons with arbitrarily set kinetic energy are substantially parallelized by the electrostatic lens and enter the planar grid perpendicularly. Instead of the planar grid, a collimator plate with parallel holes can be used as an energy band-pass filter. The angular distribution of electrons with the selected kinetic energy is projected directly onto the fluorescent screen without converging and passing through a pinhole. This is a simple but significant electron-optical design to obtain wide-range angular distribution with high angular resolution, and the analyzer can be suitably used for the two-dimensional angular distribution measurements of electrons and ions emitted from surfaces.

Jet parameters for a diverse sample of jet-launching post-AGB binaries

ABSTRACT Jets are a commonly observed phenomenon in post-asymptotic giant branch (post-AGB) binaries. Due to the orbital motion of the binary, the jet causes variable absorption in the Balmer profiles. In previous work, we have developed spatio-kinematic and radiative transfer models to reproduce the observed Balmer line variability and derive the spatio-kinematic structure of the jet and its mass-loss rate. Here, we apply our jet model to five post-AGB binaries with distinct H α line variability and diverse orbital properties. Our models fit the H α line variations very well. We estimate jet mass-loss rates between $10^{-8}\,$M$_\odot \, \text{yr}^{-1}$ and $10^{-4}\,$ M$_\odot \, \text{yr}^{-1}$, from which we deduce accretion rates on to the companion between $10^{-7}\,$ M$_\odot \, \text{yr}^{-1}$ and $10^{-3}\,$ M$_\odot \, \text{yr}^{-1}$. These accretion rates are somewhat higher than can be comfortably explained with reasonable sources of accretion, but we argue that the circumbinary disc in these systems is most likely the source feeding the accretion, although accretion from the post-AGB star cannot be ruled out. The diversity of the variability in the five objects is due to their wide ejection cones combined with a range of viewing angles, rather than inherent differences between the objects. The nature of the observations does not let us easily distinguish which jet launching model (stellar jet, disc wind, or X-wind) should be favoured. In conclusion, we show that our jet model includes the physical parameters to successfully reproduce the H α line variations and retrieve the structure and mass-loss rates of the jet for all five objects that are representative of the diverse sample of Galactic post-AGB binaries.

Matrix Hölder's Inequality and Divergence Formulation of Optimal Transport of Vector Measures

We characterise equality cases in matrix H¨older’s inequality and develop a divergence formulation of optimal transport of vector measures. As an application, we reprove the representation formula for measures in the polar cone to monotone maps. We generalise the last result to a wide class of polar cones, including polar cones to tangent cones to the unit ball in the space of differentiable functions and in the Sobolev spaces.

Experimental and Numerical Investigation on the Influence of the Rate of Injection (Roi) on Engine Performance for B100 Fuel Control Strategy in Diesel Engines

Maintaining the quality of breathing air in urban and industrial areas is one of the biggest challenges faced by humanity in the modern era. Diesel engines, as one of the main providers of energy supply for modern equipment and transport, are also unfortunately contributing highly to the deterioration of air quality. A recent research path on the limitation of diesel engine emissions is the use of alternative fuel from vegetable or animal fats or oil called biodiesel. Although the use of biodiesel has proven its efficiency in reducing emissions, it remains a problem to maintain the engine’s efficiency when shifting to biodiesel, especially due to its injection and atomization properties; most of the recent research focused on improving biodiesel fuel quality by blending it with traditional diesel fuel, but few works can be found on the regulation or control of diesel engine process when shifting to 100% biodiesel fuel (B100). This work proposes a fuel control strategy and methodology based on diesel engine operating data obtained from an experimentally designed rate of injection model (ROI) at different injection pressures and a jet and spray droplet distribution validated a two-zone model. Results show that B100 gives a higher amount of about 8% of injected fuel, a longer jet penetration of about 20 mm higher at 100 MPa injection pressure, a wider cone angle, and about a 40% increase of coarseness of the jet distribution. The experimental and numerical-based control strategy provides interacting relationships between B100 properties and specific engine features where actions shall be made to keep the engine’s efficiency when the shift is made; meanwhile, the algorithm provides a hierarchical step-by-step correcting procedure taking into account the possible degradation that could occur from the use of B100 in diesel engines.

Fake gunshot wounds in the skull\u2014post-mortem artifact caused by steel probe during police search for a missing body

The paper presents a case of a forensic autopsy of a young woman who was murdered and her dismembered body was hidden in soil and water. In the skull of the deceased, in the temporal and occipital regions, the autopsy revealed 3 round, almost identical holes, which looked like small caliber gunshot wounds. Doubts about the cause of these injuries were raised by the fact that despite the decomposition of the body, the continuity of the dura at the site of these holes remained undamaged and the absence of any trace of a bullet’s wound track in the brain, the absence of a foreign body in the cranial cavity, as well as the absence of wounds on the opposite side of the skull that could be exit wounds. A thorough analysis of the investigation and the activities carried out during the search for the missing body allowed to adopt and finally confirm the hypothesis that the above mentioned skull damage occurred during the search for the cut-off head of the deceased in shallow water by means of special tapered conical steel probes used by the rescue/search teams. Due to the structure of such a spike, i.e., a sharp end and then a wide cone, only a superficial puncture of the steel probe tip three times into the skull had taken place, which caused regular, rounded bone damage without damaging the dura and brain. The presented case indicates that sometimes post-mortem artifacts may suggest a completely different origin of wounds, which emphasizes the need for a comprehensive analysis of all possible causes of their occurrence, particularly data concerning the handling of the corpse before it is delivered to the morgue, so as not to make a diagnostic error during autopsy.

Особливості морфологічних і біометричних характеристик репродуктивних органів сосни звичайної різної стійкості в насадженнях, уражених кореневою губкою

Висвітлено результати дослідження морфологічних та біометричних характеристик дерев сосни звичайної різного санітарного стану в уражених кореневою губкою насадженнях V і VI класів віку. В осередках усихання відібрано дерева без ознак ослаблення («стійкі») та з ознаками хвороби («хворі»), а в міжосередковому просторі – середні за таксаційними показниками дерева І категорії санітарного стану – контроль. Оцінювали якісні й кількісні характеристики шишок, насіння, крилаток (забарвлення, розміри, форму та масу). Розміри генеративних органів сосни з підвищеною резистентністю виявилися більшими, ніж у дерев із ознаками хвороби та контрольних, що є наслідком адаптації дерева до відкритого простору прогалини на тлі розвитку патологічних процесів і з генетичними особливостями сосни пов’язано мало. Дерева з підвищеною резистентністю в осередках усихання характеризуються суттєво більшою варіабельністю показників діаметра (Cv = 21,2…27,4 %), ніж «хворі» (Cv = 8,9…12,1 %).

Large deformation of a conductive nanodroplet in a strong electric field

Despite their remarkable effect on printing accuracy and uniformity, charge migrations that dominate the deformation of ink droplets during electrohydrodynamic jet printing have not been widely investigated. In this work, the large deformation mechanisms of a conductive nanodroplet under a strong electric field are examined from the point of view of charge migrations. It is found that the charge migrations include the charge relaxation in the bulk of the droplet and surface charge convection at the fluid interface. A conductive nanodroplet first evolves into an ellipsoid through charge relaxation. Then, the ellipsoid is deformed by the convection of the surface charges in four modes, namely, tip streaming (mode 1), lobe formation (mode 2), finger stretching (mode 3), and dumbbell stretching (mode 4). Finally, the stretched nanodroplet is broken into secondary droplets. Modes 1, 2, and 4 are in agreement with the experimental observations. Furthermore, it is found that over 20% of the charges are distributed inside the bulk nanodroplet and the other charges are distributed at the surface, causing the four deformation modes. Analysis based on the electric Reynolds number (the ratio of electric field force to viscous force) and the Coulombic capillary number (the ratio of surface tension to Coulombic force) shows that the nanodroplet is prolate if the electric field force is dominant. When the Coulombic force plays a crucial role, the nanodroplet deforms into an ellipsoid with wide cones. By contrast, the nanodroplet will generate hemispherical ends if the deformation is dominated by the effect of surface tension.

Post-conization follow-up of patients with CIN 2/3 with different amount of distance to negative cone biopsy margin: a retrospective cohort study

The aim of this study was to investigate whether patients with CIN 2/3 with different amount of distance to negative cone biopsy margin differ in terms of post-conization follow-up results. Cold-knife cone specimens with a negative surgical margin with a diagnosis of CIN-2/3 were selected. The minimum distance between the margin and lesion was categorised as less than 2 mm (Group-1), 2–5 mm (Group-2), or more than 5 mm (Group-3). There were no statistically significant differences between groups in terms of postoperative cone-biopsy results (p = .61). Furthermore, there were no statistically significant differences between groups in terms of cytology at 6 months and 12 months (p = .33 and p = .80, respectively). Results of the present study indicate that the amount of distance of lesion to cone biopsy margin seems to have no effect on follow-up results in patients with negative surgical margin.Impact StatementWhat is already known on this subject? Negative surgical margins on conization are associated with lower rates of lesion recurrence. Only the efficacy of volume and size of cone biopsy specimens have been analysed on lesion recurrence. However, there is no clear definition of the minimum distance of a negative margin during cone biopsy.What do the results of this study add? To the best of our knowledge, this is the first study describing the post-conization follow-up of patients with CIN 2/3 with different amount of distance to negative cone biopsy margin. Patients who underwent surgical treatment with a wider cone biopsy margin and narrower cone biopsy margin demonstrated similar follow-up results.What are the implications of these findings for clinical practice and/or further research? The present study provides valuable information to guide physicians performing conizations with an appropriate amount of negative surgical margin. Future studies investigating the effect of different amount of distance to negative cone biopsy margin on gynaecologic and obstetrics complications such as stenosis, bleeding, and preterm labour, low birth weight, and perinatal mortality are needed to show the benefits of a narrower distance to negative cone biopsy margin.

Investigation of the structures in the unstable rotating-cone boundary layer

Experiments show that crossflow vortices in the boundary layer on a rotating wide cone start to meander before breakdown. The structural development of the overturning process of these vortices, where high-momentum upwelling of the vortices leads to transition to turbulence, is described in detail.

Comparative analysis of Kameton spraying parameters of different manufacturers

Based on a comparative analysis of the key dispersion parametries of spray-aerosol forms of drugs Kameton from different manufacturers the most effective drug in terms of delivery to the mucous membrane of the throat was choosen. The objects of study were 5 drugs brand Kameton, produced in the form of a metered-dose spray manufacturers of 'Firm 'VIPSMED' (RF), 'Altayvitaminy' (RF), 'Samaramedprom' (RF), 'ESCO-Pharm' (Armenia) and metered-dose aerosol - of 'Pharmstandard' (RF). Measurement of the dynamic characteristics of the spray and the dispersed composition of the spray was carried out by the method of shadow photography with digital image processing using the 'POLIS' system. Diagnose spray pattern spray angle and the shape of the cone spray pattern showed that the spray pattern is in the form of a wide hollow cone is in the drugs Kameton production of 'Firm 'VIPSME' and 'ESCO-Pharm' (Armenia). The study of the parameter 'spray duration' showed that in all studied sprays the classical three-stage spray is carried out. In the aerosol production of 'Pharmstandard' no initial and final stage, spraying takes place in jet, without forming a cone. The calculation of the proportion of the duration of the main stage to the total duration of the spray showed that the maximum value of this parameter is achieved in the spray production of 'Firm 'VIPSMED'. A comparison of five drugs Kameton dispersed composition showed that the drug Kameton production of 'Pharmstandard' refers to the fine, and the others studied - to the coarse aerosols, which is more preferable. A comparative analysis of the drugs Kameton five different manufacturers showed that the most effective mode of operation of the spray packaging system, providing the most favorable conditions for the delivery of the drug to the mucous membrane of the throat, is carried out in drug production of 'Firm 'VIPSMED'.