Проектный анализ аэродинамических схем спускаемых аппаратов капсульной формы численным методом по ньютонианской теории обтекания

The article objective is to review the basic design parameters of space capsule (SC) to select a rational shape at the early stages of design.The choice is based on the design parameters such as a volume filling factor (volumetric efficiency of shape), aerodynamic coefficients, margin of stability, and centering characteristics.The aerodynamic coefficients are calculated by a numerical method based on approximate Newton's theory. A proposed engineering technique uses this theory to calculate aerodynamic characteristics of the capsule shapes. The gist of the technique is in using a developed programme to generate capsule shapes and provide numerical calculation of aerodynamic characteristics. The accuracy of the calculation, performed according to proposed technique, tends to the results obtained by analytical integral dependencies according to the Newtonian technique.When considering the stability of the capsule shapes the paper gives a diagram of the aerodynamic forces acting on the SC in the descent phase, and using the aerodynamically-shaped SC "Soyuz" as an example analyses a dangerous moment of flow at adverse angles of attack.After determining a design center-of-mass position to meet the stability requirements it is necessary at the early stage, before starting the SC layout work, to evaluate the complexity of bringing the center-of-mass to the specified point. In this regard have been considered such design parameters of the shape as a volume-centering and surface-centering coefficients.Next, using the above engineering technique are calculated aerodynamic characteristics of capsule shapes similar to the well-known SC "Soyuz", "Zarya 2" and the command module "Apollo".All calculated design parameters are summarized in the table. Currently, among the works cited in foreign publications concerning the contours of winged configuration of the type "Space Shuttle" some papers are close to the proposed technique.Application of the proposed engineering technique allows a multi-fold increasing rate of the capsule shape analysis at an early designing stage. Reviewed design parameters can be further considered as the optimality criteria when choosing the SC shape, and the engineering technique can be further extended to a full-fledged programme on the numerical selection of the optimal aerodynamic solutions with continuously transferred results for engineering development of the SC.В данной статье рассмотрены три типа космических спускаемых аппаратов (СА) капсульной формы, аналогичных СА «Союз» и СА «Аполлон». Исследуются аэродинамические характеристики этих аппаратов в гиперзвуковом диапазоне скоростей по ньютонианской теории. Предложена инженерная методика определения аэродинамических характеристик капсульных аппаратов, которая может быть использована на стадии предварительных проектных исследований. Данная методика может оказаться востребованной в учебном процессе для соответствующих специальностей. DOI: 10.7463/aersp.0415.081389

Степень комфортности кабины спускаемых аппаратов капсульной формы

The article formulates the task of selecting a design-layout pattern for a transport spacecraft, in terms of reaching a proper comfort level for the crew to have appropriate functioning. Using the example of a domestic spacecraft and an American one, it has been shown that the type of launch vehicle, the launch specifics, the operational overloads, and the overall mass restrictions have a dramatic impact on the choice of the design-layout pattern of the spacecraft. The free volume of the pressure cockpit per each member of the crew is considered as the main characteristic to show a level of the spacecraft comfort. Using the average statistical data on the layout density of different equipment, the article estimates the possible increase of this characteristic for the cutting-edge descent vehicles. Using the example of the descent vehicles of Soyuz and Apollo class, the article shows a dependence of the raising weight of a descent vehicle on the free volume of its pressure cockpit. Attention is drawn to the fact that the limit of increasing free space of the spacecraft compartments to achieve maximum comfort should correspond to a set of functions that the crew performs in the compartments considered. Otherwise, the increase in the spacecraft mass will prove to be unjustified. The results stated in the article can be useful to developers of manned spacecraft, as well as to teachers and students. In the long term it is worthwhile adding the article material with the mass and volume indicators, as well as with the estimate results of the comfort level of modern manned spacecrafts being under design in Russia and USA, such as PTK NP (“Federation”), “Orion”, “Dragon V2”.В статье изложена проблема выбора проектно-компоновочной схемы транспортного космического корабля с учетом достижения необходимой для нормального функционирования экипажа степени комфортности. На примере отечественных и американских космических кораблей показано, что на выбор проектно-компоновочной схемы космического корабля оказывают решающее влияние тип ракеты-носителя, специфика старта, эксплуатационные перегрузки, габаритно-массовые ограничения. Свободный объем гермокабины, приходящийся на каждого члена экипажа, рассматривается в качестве основного показателя, характеризующего степень комфортности космического корабля. Используя среднестатистические данные по плотности компоновки различного оборудования, проведена оценка возможного увеличения этого показателя для современных спускаемых аппаратов. На примере спускаемых аппаратов класса «Союз» и «Аполлон» приведена зависимость роста массы спускаемого аппарата от свободного объема его гермокабины. Обращено внимание на тот факт, что предел увеличения свободного объема отсеков космического корабля для достижения максимальной степени комфортности должен соответствовать набору функций, которые выполняет экипаж в рассматриваемых отсеках В противном случае увеличение массы космического корабля окажется неоправданным. Результаты, изложенные в статье, могут быть полезны разработчикам пилотируемых космических аппаратов, а также преподавателям и студентам. В перспективе целесообразно дополнить материал статьи массовыми и объемными показателями, а также результатами оценки степени комфортности проектируемых в настоящее время в России и США современных пилотируемых космических аппаратов, таких как ПТК НП («Федерация»), «Орион», «Dragon V2»

Thyroid cancer risk in Belarus among children and adolescents exposed to radioiodine after the Chornobyl accident

BACKGROUND: Previous studies showed an increased risk of thyroid cancer among children and adolescents exposed to radioactive iodines released after the Chornobyl (Chernobyl) accident, but the effects of screening, iodine deficiency, age at exposure and other factors on the dose-response are poorly understood. METHODS: We screened 11 970 individuals in Belarus aged 18 years or younger at the time of the accident who had estimated (131)I thyroid doses based on individual thyroid activity measurements and dosimetric data from questionnaires. The excess odds ratio per gray (EOR/Gy) was modelled using linear and linear-exponential functions. RESULTS: For thyroid doses \u3c5 \u3eGy, the dose-response was linear (n=85; EOR/Gy=2.15, 95% confidence interval: 0.81-5.47), but at higher doses the excess risk fell. The EOR/Gy was significantly increased among those with prior or screening-detected diffuse goiter, and larger for men than women, and for persons exposed before age 5 than those exposed between 5 and 18 years, although not statistically significant. A somewhat higher EOR/Gy was estimated for validated pre-screening cases. CONCLUSION: 10-15 years after the Chornobyl accident, thyroid cancer risk was significantly increased among individuals exposed to fallout as children or adolescents, but the risk appeared to be lower than in other Chornobyl studies and studies of childhood external irradiation

The Flux-Line Lattice in Superconductors

Magnetic flux can penetrate a type-II superconductor in form of Abrikosov vortices. These tend to arrange in a triangular flux-line lattice (FLL) which is more or less perturbed by material inhomogeneities that pin the flux lines, and in high-$T_c$ supercon- ductors (HTSC's) also by thermal fluctuations. Many properties of the FLL are well described by the phenomenological Ginzburg-Landau theory or by the electromagnetic London theory, which treats the vortex core as a singularity. In Nb alloys and HTSC's the FLL is very soft mainly because of the large magnetic penetration depth: The shear modulus of the FLL is thus small and the tilt modulus is dispersive and becomes very small for short distortion wavelength. This softness of the FLL is enhanced further by the pronounced anisotropy and layered structure of HTSC's, which strongly increases the penetration depth for currents along the c-axis of these uniaxial crystals and may even cause a decoupling of two-dimensional vortex lattices in the Cu-O layers. Thermal fluctuations and softening may melt the FLL and cause thermally activated depinning of the flux lines or of the 2D pancake vortices in the layers. Various phase transitions are predicted for the FLL in layered HTSC's. The linear and nonlinear magnetic response of HTSC's gives rise to interesting effects which strongly depend on the geometry of the experiment.Comment: Review paper for Rep.Prog.Phys., 124 narrow pages. The 30 figures do not exist as postscript file

Project Analysis of Aerodynamics Configuration of Re-entry Сapsule-shaped Body Based on Numerical Methods for Newtonian Flow Theory

The article objective is to review the basic design parameters of space capsule (SC) to select a rational shape at the early stages of design.The choice is based on the design parameters such as a volume filling factor (volumetric efficiency of shape), aerodynamic coefficients, margin of stability, and centering characteristics.The aerodynamic coefficients are calculated by a numerical method based on approximate Newton's theory. A proposed engineering technique uses this theory to calculate aerodynamic characteristics of the capsule shapes. The gist of the technique is in using a developed programme to generate capsule shapes and provide numerical calculation of aerodynamic characteristics. The accuracy of the calculation, performed according to proposed technique, tends to the results obtained by analytical integral dependencies according to the Newtonian technique.When considering the stability of the capsule shapes the paper gives a diagram of the aerodynamic forces acting on the SC in the descent phase, and using the aerodynamically-shaped SC "Soyuz" as an example analyses a dangerous moment of flow at adverse angles of attack.After determining a design center-of-mass position to meet the stability requirements it is necessary at the early stage, before starting the SC layout work, to evaluate the complexity of bringing the center-of-mass to the specified point. In this regard have been considered such design parameters of the shape as a volume-centering and surface-centering coefficients.Next, using the above engineering technique are calculated aerodynamic characteristics of capsule shapes similar to the well-known SC "Soyuz", "Zarya 2" and the command module "Apollo".All calculated design parameters are summarized in the table. Currently, among the works cited in foreign publications concerning the contours of winged configuration of the type "Space Shuttle" some papers are close to the proposed technique.Application of the proposed engineering technique allows a multi-fold increasing rate of the capsule shape analysis at an early designing stage. Reviewed design parameters can be further considered as the optimality criteria when choosing the SC shape, and the engineering technique can be further extended to a full-fledged programme on the numerical selection of the optimal aerodynamic solutions with continuously transferred results for engineering development of the SC

Project Analysis of Aerodynamics Configuration of Re-entry Сapsule-shaped Body Based on Numerical Methods for Newtonian Flow Theory

The article objective is to review the basic design parameters of space capsule (SC) to select a rational shape at the early stages of design.The choice is based on the design parameters such as a volume filling factor (volumetric efficiency of shape), aerodynamic coefficients, margin of stability, and centering characteristics.The aerodynamic coefficients are calculated by a numerical method based on approximate Newton's theory. A proposed engineering technique uses this theory to calculate aerodynamic characteristics of the capsule shapes. The gist of the technique is in using a developed programme to generate capsule shapes and provide numerical calculation of aerodynamic characteristics. The accuracy of the calculation, performed according to proposed technique, tends to the results obtained by analytical integral dependencies according to the Newtonian technique.When considering the stability of the capsule shapes the paper gives a diagram of the aerodynamic forces acting on the SC in the descent phase, and using the aerodynamically-shaped SC "Soyuz" as an example analyses a dangerous moment of flow at adverse angles of attack.After determining a design center-of-mass position to meet the stability requirements it is necessary at the early stage, before starting the SC layout work, to evaluate the complexity of bringing the center-of-mass to the specified point. In this regard have been considered such design parameters of the shape as a volume-centering and surface-centering coefficients.Next, using the above engineering technique are calculated aerodynamic characteristics of capsule shapes similar to the well-known SC "Soyuz", "Zarya 2" and the command module "Apollo".All calculated design parameters are summarized in the table. Currently, among the works cited in foreign publications concerning the contours of winged configuration of the type "Space Shuttle" some papers are close to the proposed technique.Application of the proposed engineering technique allows a multi-fold increasing rate of the capsule shape analysis at an early designing stage. Reviewed design parameters can be further considered as the optimality criteria when choosing the SC shape, and the engineering technique can be further extended to a full-fledged programme on the numerical selection of the optimal aerodynamic solutions with continuously transferred results for engineering development of the SC.</p

A Cockpit Comfort Level of the Descent Capsule-Shaped Vehicles

The article formulates the task of selecting a design-layout pattern for a transport spacecraft, in terms of reaching a proper comfort level for the crew to have appropriate functioning. Using the example of a domestic spacecraft and an American one, it has been shown that the type of launch vehicle, the launch specifics, the operational overloads, and the overall mass restrictions have a dramatic impact on the choice of the design-layout pattern of the spacecraft. The free volume of the pressure cockpit per each member of the crew is considered as the main characteristic to show a level of the spacecraft comfort. Using the average statistical data on the layout density of different equipment, the article estimates the possible increase of this characteristic for the cutting-edge descent vehicles. Using the example of the descent vehicles of Soyuz and Apollo class, the article shows a dependence of the raising weight of a descent vehicle on the free volume of its pressure cockpit. Attention is drawn to the fact that the limit of increasing free space of the spacecraft compartments to achieve maximum comfort should correspond to a set of functions that the crew performs in the compartments considered. Otherwise, the increase in the spacecraft mass will prove to be unjustified. The results stated in the article can be useful to developers of manned spacecraft, as well as to teachers and students. In the long term it is worthwhile adding the article material with the mass and volume indicators, as well as with the estimate results of the comfort level of modern manned spacecrafts being under design in Russia and USA, such as PTK NP (“Federation”), “Orion”, “Dragon V2”

Substorms during the August 10-11 sawtooth event.

Sawtooth events have been identified at geosynchronous orbit as large-amplitude quasiperiodic (2–4 hour period) modulations of the energetic electron and ion fluxes. They are called sawtooth events because the shape of the flux versus time profiles are composed of rapid increases followed by gradual decreases that resemble the teeth on a saw blade. Although much of the phenomenology associated with sawtooth events is substorm-like, there is still debate as to whether the individual teeth are substorms or not. Here we examine each of the teeth associated with the 10–11 August 2000 sawtooth event in detail. We find that all but one of the teeth were associated with injections at geosynchronous orbit and that most of the teeth were consistent with the hypothesis that they are predominantly caused by unusually large and longitudinally extended substorms. A few were unclear or complex, and the final flux enhancement at 1845:36 UT was not a substorm but a solar wind shock-associated disturbance. In addition, the presence of numerous dispersionless flux perturbations in the LANL SOPA data provides support for the hypothesis that solar wind pressure variations can modulate the flux profiles to some extent. For the substorm events we find that the geosynchronous particle injections were neither globally simultaneous nor globally dispersionless but were instead consistent with a nightside/duskside source in most cases. Similarly, we show that the field dipolarizations were also not global and simultaneous. Each of the substorms was also associated with high-latitude negative H bays, middle- and low-latitude positive H bays, a partial recovery in Sym-H, and the onset of Pi2 ULF pulsations. In addition, we show that the auroral distribution develops in a systematic way during each cycle of a sawtooth substorm event. Specifically, a localized auroral onset develops on the lower branch of a thinned double-oval distribution. The location of onset is typically premidnight and often occurs to the west of intense omega band forms. This is followed by westward, eastward, and poleward expansion and the copious production of auroral streamers which can develop in complex patterns including a “spoke-like” morphology. The double-oval configuration thins again during the stretching phase until the next onset occurs and the cycle repeats. A schematic representation of the auroral dynamics associated with sawtooth substorms is also presented

Treatment of patients with refractory immune thrombocytopenia: literature review and case report

ITP is a rare chronic autoimmune disease with isolated platelets decrease and high risk of bleeding complications. Standard treatment (steroids, HD of immunoglobulin and splenectomy) are effective in 70–90 % of patients, but in 10 % of them platelet count is not increased. A new group of drugs — TPO receptor agonists — is able to help to these patients. Their high efficacy in chronic ITP has shown in several studies, but the experience of their application before surgery is limited. We used romiplostim in 3 patients with chronic refractory ITP before surgery (2 — splenectomy and 1 — resection of nasal tumor). Thefirst patient, 19 years old, received multiple steroids, immunoglobulins and rituximab courses without effect during the last year. Platelets count was 7–15 10 9/l and hematuria and steroid tibia necrosis were revealed. Splenectomy was decided to be done. Because of the risk of hemorrhagic complications patients received romiplostim (3 mkg/kg) during 4 weeks. Upon reaching platelet counts 240 10 9/l splenectomywas performed. A postoperative platelet count was 1200 10 9/l, 3 weeks later — 400 10 9/l. The second patient, 64 years old, with a3-year ITP history was admitted to the hospital for splenectomy, but the platelet count (5.7 10 9/l) and a hemorrhagic syndrome with a constant need for platelet transfusions despite high doses of steroids and immunoglobulin received, interfere with the safety of operations.Romiplostim was administered in increasing doses during 6 weeks to a maximum 10 mg/kg. Platelet count was 148 10 9/l and splenectomy was performed. Postoperative platelet count was 380 10 9/l, 3 weeks later — 120 10 9/l. The third patient, 22 years old, with a 15-year ITP history admitted with severe epistaxis. Nasal tumor was revealed. Patient was treated with immunoglobulins and steroids, and biopsy was attempt when platelet count increased to 50 10 9/l. This procedure ended with severe bleeding. Patient received 1 mg/kg of romiplostim and a week later platelet count was 250 10 9/l. Successfully tumor resection was done. No romiplostim side effects or thrombotic complications during postoperative period were found. The obtained data together with similar case reports of successful surgery after TPO-agonists administration allow considering romiplostim as an effective method of thrombocytopenia therapy before surgery in ITP patients

Treatment of patients with refractory immune thrombocytopenia: literature review and case report

ITP is a rare chronic autoimmune disease with isolated platelets decrease and high risk of bleeding complications. Standard treatment (steroids, HD of immunoglobulin and splenectomy) are effective in 70–90 % of patients, but in 10 % of them platelet count is not increased. A new group of drugs — TPO receptor agonists — is able to help to these patients. Their high efficacy in chronic ITP has shown in several studies, but the experience of their application before surgery is limited. We used romiplostim in 3 patients with chronic refractory ITP before surgery (2 — splenectomy and 1 — resection of nasal tumor). Thefirst patient, 19 years old, received multiple steroids, immunoglobulins and rituximab courses without effect during the last year. Platelets count was 7–15 10 9/l and hematuria and steroid tibia necrosis were revealed. Splenectomy was decided to be done. Because of the risk of hemorrhagic complications patients received romiplostim (3 mkg/kg) during 4 weeks. Upon reaching platelet counts 240 10 9/l splenectomywas performed. A postoperative platelet count was 1200 10 9/l, 3 weeks later — 400 10 9/l. The second patient, 64 years old, with a3-year ITP history was admitted to the hospital for splenectomy, but the platelet count (5.7 10 9/l) and a hemorrhagic syndrome with a constant need for platelet transfusions despite high doses of steroids and immunoglobulin received, interfere with the safety of operations.Romiplostim was administered in increasing doses during 6 weeks to a maximum 10 mg/kg. Platelet count was 148 10 9/l and splenectomy was performed. Postoperative platelet count was 380 10 9/l, 3 weeks later — 120 10 9/l. The third patient, 22 years old, with a 15-year ITP history admitted with severe epistaxis. Nasal tumor was revealed. Patient was treated with immunoglobulins and steroids, and biopsy was attempt when platelet count increased to 50 10 9/l. This procedure ended with severe bleeding. Patient received 1 mg/kg of romiplostim and a week later platelet count was 250 10 9/l. Successfully tumor resection was done. No romiplostim side effects or thrombotic complications during postoperative period were found. The obtained data together with similar case reports of successful surgery after TPO-agonists administration allow considering romiplostim as an effective method of thrombocytopenia therapy before surgery in ITP patients.</p