Body frontal area in passerine birds

Projected body frontal area is used when estimating the parasite drag of bird flight. We investigated the relationship between projected frontal area and body mass among passerine birds, and compared it with an equation based on waterfowl and raptors, which is used as default procedure in a widespread software package for flight performance calculations. The allometric equation based on waterfowl/raptors underestimates the frontal area compared to the passerine equation presented here. Consequently, revising the actual frontal areas of small birds will concomitantly change the values of the parasite drag coefficient. We suggest that the new equation S-b = 0.0129m(B)(0.61) (m(2)) where m(B) is body mass (kg) should be used when a value of frontal area is needed for passerines

Gliding flight in a jackdaw: a wind tunnel study

We examined the gliding flight performance of a jackdaw Corvus monedula in a wind tunnel. The jackdaw was able to glide steadily at speeds between 6 and 11 m s(-1). The bird changed its wingspan and wing area over this speed range, and we measured the so-called glide super-polar, which is the envelope of fixed-wing glide polars over a range of forward speeds and sinking speeds. The glide super-polar was an inverted U-shape with a minimum sinking speed (V(ms)) at 7.4 m s(-1) and a speed for best glide (V(bg)) at 8.3 m s(-)). At the minimum sinking speed, the associated vertical sinking speed was 0.62 m s(-1). The relationship between the ratio of lift to drag (L:D) and airspeed showed an inverted U-shape with a maximum of 12.6 at 8.5 m s(-1). Wingspan decreased linearly with speed over the whole speed range investigated. The tail was spread extensively at low and moderate speeds; at speeds between 6 and 9 m s(-1), the tail area decreased linearly with speed, and at speeds above 9 m s(-1) the tail was fully furled. Reynolds number calculated with the mean chord as the reference length ranged from 38 000 to 76 000 over the speed range 6-11 m s(-1). Comparisons of the jackdaw flight performance were made with existing theory of gliding flight. We also re-analysed data on span ratios with respect to speed in two other bird species previously studied in wind tunnels. These data indicate that an equation for calculating the span ratio, which minimises the sum of induced and profile drag, does not predict the actual span ratios observed in these birds. We derive an alternative equation on the basis of the observed span ratios for calculating wingspan and wing area with respect to forward speed in gliding birds from information about body mass, maximum wingspan, maximum wing area and maximum coefficient of lift. These alternative equations can be used in combination with any model of gliding flight where wing area and wingspan are considered to calculate sinking rate with respect to forward speed

Desflurane results in higher cerebral blood flow than sevoflurane or isoflurane at hypocapnia in pigs.

Background: In clinical neuroanaesthesia, the increase in cerebral blood flow (CBF) and intracranial pressure caused by the cerebral vasodilative effects of an inhalational anaesthetic agent is counteracted by the cerebral vasoconstriction induced by hypocapnia. Desflurane and sevoflurane may have advantages over the more traditionally used isoflurane in neuroanaesthesia but their dose-dependent vasodilative effects at hypocapnia have not been compared in the same model using truly equipotent minimal alveolar concentrations (MACs). Method: Desflurane, sevoflurane and isoflurane were administered in a randomized order to six pigs at 0.5 and 1.0 MAC. The intra-arterial xenon clearance technique was used to calculate CBF. Blood pressure was invasively monitored. Cerebral and systemic physiological variables were recorded first at normocapnia (PaCO2 5.6 kPa) and then at hypocapnia (PaCO2 3.5 kPa). Electroencephalographic (EEG) activity was continuously recorded. Results: None of the three agents abolished cerebrovascular reactivity to hyperventilation, and at 0.5 MAC all had similar effects on CBF at hypocapnia. Desflurane at 1.0 MAC was associated with 16% higher CBF (P = 0.027) at hypocapnia than isoflurane, and with 24% higher CBF (P = 0.020) than sevoflurane. There was no seizure activity in the EEG. Conclusion: More cerebral vasodilation at hypocapnia with high doses of desflurane than with sevoflurane or isoflurane indicates that desflurane might be less suitable for neuroanaesthesia than sevoflurane and isoflurane

Comparison of integral equations for the Maxwell transmission problem with general permittivities

Two recently derived integral equations for the Maxwell transmission problem are compared through numerical tests on simply connected axially symmetric domains for non-magnetic materials. The winning integral equation turns out to be entirely free from false eigenwavenumbers for any passive materials, also for purely negative permittivity ratios and in the static limit, as well as free from false essential spectrum on non-smooth surfaces. It also appears to be numerically competitive to all other available integral equation reformulations of the Maxwell transmission problem, despite using eight scalar surface densities.Comment: 35 pages, 9 figure

An efficient full wave solver for eddy currents

An integral equation reformulation of the Maxwell transmission problem is presented. The reformulation uses techniques such as tuning of free parameters and augmentation of close-to-rank-deficient operators. It is designed for the eddy current regime and works both for surfaces of genus $0$ and $1$. Well-conditioned systems and field representations are obtained despite the Maxwell transmission problem being ill-conditioned for genus $1$ surfaces due to the presence of Neumann eigenfields. Furthermore, it is shown that these eigenfields, for ordinary conductors in the eddy current regime, are different from the classical Neumann eigenfields for superconductors. Numerical examples, based on the reformulation, give an unprecedented $13$-digit accuracy both for transmitted and scattered fields.Comment: Accepted for publication in Computers and Mathematics with Application

Проектирование технологического процесса изготовления цилиндра и оснастки

РЕФЕРАТ Выпускная квалификационная работа 98 с., 12 рис., 27 табл., 7 источников, 6 прил. Ключевые слова: цилиндр, оснастка, литье, сверление, приспособление, технологический процесс. Объектом исследования является проектирование технологического процесса изготовления цилиндра Цель работы: проектирование технологического процесса изготовления цилиндра и оснастки В процессе исследования проводились анализ технологического процесса, технико-экономическая анализ, конструирование приспособления для сверления В результате выполнения работы был разработан технологический процесс изготовления детали цилиндр и сконструировано приспособление для сверления Основные конструктивные, технологические и технико-эксплуатационные характеристики: сконструированное приспособление для сверлABSTRACT Final qualifying work 98 p., 12 Fig., 27 tab., 7 springs, 6 ADJ. Key words: cylinder, tooling, casting, drilling, fitting, process. The object of study is (are) the Design of technological process of manufacturing of cylinder Goal – to Design the technological process of manufacturing of cylinder and snap In the process of investigation the analysis of the technological feasibility analysis, designing fixtures for drilling The result of the work was developed technological process of manufacturing parts and the cylinder fixture is designed for drilling The basic constructive, technological, technical-operational and features: the fixture is Designed for drilling consists of a casing, rod rack, cover, cylinder, prisms and the plate conductor. Level of implementation: the te

Optimizing NUCA organizations and wiring alternatives for large caches with CACTI 6.0

Journal ArticleA significant part of future microprocessor real estate will be dedicated to L2 or L3 caches. These on-chip caches will heavily impact processor performance, power dissipation, and thermal management strategies. There are a number of interconnect design considerations that influence power/performance/area characteristics of large caches, such as wire models (width/spacing/repeaters), signaling strategy (RC/differential/transmission), router design, etc. Yet, to date, there exists no analytical tool that takes all of these parameters into account to carry out a design space exploration for large caches and estimate an optimal organization. In this work, we implement two major extensions to the CACTI cache modeling tool that focus on interconnect design for a large cache. First, we add the ability to model different types of wires, such as RC-based wires with different power/delay characteristics and differential low-swing buses. Second, we add the ability to model Non-uniform Cache Access (NUCA). We not only adopt state-of-the-art design space exploration strategies for NUCA, we also enhance this exploration by considering on-chip network contention and a wider spectrum of wiring and routing choices. We present a validation analysis of the new tool (to be released as CACTI 6.0) and present a case study to showcase how the tool can improve architecture research methodologies

An eccentrically biased rehabilitation program early after TKA surgery

Journal ArticleRehabilitation services are less-studied aspects of the management following total knee arthroplasty (TKA) despite long-term suboptimal physical functioning and chronic deficits in muscle function. This paper describes the preliminary findings of a six-week (12 session) eccentrically-biased rehabilitation program targeted at deficits in physical function and muscle function, initiated one month following surgery. A quasiexperimental, one group, pretest-posttest study with thirteen individuals (6 female, 7 male; mean age 57 ? 7 years) examined the effectiveness of an eccentrically-biased rehabilitation program. The program resulted in improvements in the primary physical function endpoints (SF-36 physical component summary and the six-minute walk test) with increases of 59% and 47%, respectively. Muscle function endpoints (knee extension strength and power) also increased 107% and 93%, respectively. Eccentrically-biased exercise used as an addition to rehabilitation may help amplify and accelerate physical function following TKA surgery