The Possibility of Noticing the Cyclists Based on Reflective Effect of the Elements on the Bicycle Pedals

The article presents the results of the research describing the changes of bicycle pedal angle relative to the ground, depending on the bicycle crank setting, and the impact of these parameters on detecting the reflective effect emitted by the reflective elements mounted on the bicycle pedals. The results of the road tests determining the cyclist detecting by a car driver, when bicycle is equipped only with bicycle pedals, reflective lights, illuminated with car′s passing lights are also presented. The research described in this article has been carried out for the purpose of reviewing the causes of traffic accidents, occurring at night, in the areas not illuminated by the street lights, in which the cyclists using defective bicycles (according to the regulations) took part

Wpływ gospodarki rybackiej na awifaunę lęgową stawów karpiowych Lubelszczyzny

Wydział PrzyrodniczyKarp może znacząco wpływać na siedlisko zajmowane przez ptaki, stanowiąc pokarm ptaków lub konkurując z nimi o pożywienie. Badano jaki ma wpływ wiek hodowanego karpia oraz panujących w stawach warunków na gatunki lęgowe ptaków wodnych. Stawy były monokulturowe (tylko karp) i jednorocznikowe: 0+, 1+, 2+. Badania prowadzono w zbiornikach, charakteryzujących się ekstensywną gospodarką hodowlaną. Podczas sezonu lęgowego, w latach 2005-07 skontrolowano 53 stawy na terenie czterech kompleksów, oddalonych około 25-45 km od Lublina w południowo-wschodniej Polsce. Badania wykazały, że głównymi czynnikami wpływającymi na preferencje siedliskowe ptaków były: kategoria stawu, udział powierzchni helofitów i otoczenie stawów. Stawy 0+ charakteryzowały się najlepszymi warunkami pokarmowymi wykazując najwyższą biomasę bezkręgowców i płazów. Kategoria stawu miała istotny wpływ na wybór siedliska przez perkozka, perkoza rdzawoszyjego, zausznika i łyskę, które preferowały stawy 0+. Z kolei perkoz dwuczuby, bąk i kokoszka preferowały stawy 1+. Najwyższe zagęszczenia rodziny kaczek osiągały na stawach 0+. Natomiast stawy 2+ miały najmniejsze znaczenie dla ptaków lęgowych. Bogactwo gatunkowe wykazywało pozytywną korelację z powierzchnią stawu oraz z udziałem helofitów w stawach i krajobrazu zurbanizowanego w otoczeniu stawów. Stawy 1+ wykazywały najwyższe bogactwo gatunkowe. Uzyskane wyniki pokazują, że wiek ryby jest istotnym czynnikiem wpływającym na wybór siedliska lęgowego przez ptaki.SUMMARY - Common carp may significantly affect habitat use by birds, either as their prey or as competitors. The effects of age classes of common carp cohorts together with other biotic and abiotic pond characteristics on the distribution of breeding waterbirds were examined in a semi-natural system of monocultured ponds, where three fish age classes were separately stocked (0+, 1+, 2+). The study was conducted in at extensively managed carp ponds. During three breeding seasons, in 2005, 2006 and 2007, 53 ponds were surveyed. The ponds belonged to four pond complexes situated 25-45 km from Lublin in south-eastern Poland. The three environmental variables as best differentiating habitat preferences of waterbirds were: fish age, emergent vegetation cover and surrounding landscape. The best food conditions were in ponds with 0+ fish. There was the highest biomass of macroinvertebrates and amphibians. Little Grebe, red-necked grebe, black-necked grebe and coot preferred ponds with 0+ fish. Great crested grebe, great bittern and moorhen preferred ponds with 1+ fish. The highest densities of duck brood were on ponds with 0+ fish. No species was found to be positively associated with 2+ fish. Total species richness was positively correlated with pond size, the proportion of emergent vegetation and urbanized habitat close to shoreline. The highest species richness was on ponds with 1+ fish. The results show that fish age is an important factor for breeding habitat choice in avian communities

Effect of sildenafil on the activity of some antidepressant drugs and electroconvulsive shock treatment in the forced swim test in mice

Sildenafil, a potent and selective inhibitor of phosphodiesterase type 5, is used clinically to treat erectile dysfunction and pulmonary arterial hypertension. It is often taken by patients suffering from depression and receiving antidepressant drug treatment. However, its influence on the efficacy of antidepressant treatment was not sufficiently studied. Therefore, the aim of the present study was to investigate the influence of sildenafil on the anti-immobility action of several antidepressant drugs (i.e., sertraline, fluvoxamine, citalopram, maprotiline, trazodone, and agomelatine) as well as on antidepressant-like effect of electroconvulsive stimulations in the forced swim test in mice. The obtained results showed that acute sildenafil treatment enhanced the antidepressant-like activity of all of the studied drugs. The observed effects were not due to the increase in locomotor activity. The interactions between sildenafil and sertraline, maprotiline, and trazodone were pharmacodynamic in nature, as sildenafil did not affect concentrations of these drugs neither in serum nor in brain tissue. Increased concentrations of fluvoxamine, citalopram, and agomelatine in brain tissue evoked by sildenafil co-administration suggest that pharmacokinetic interactions between sildenafil and these drugs are very likely. Sildenafil injected acutely did not alter the antidepressant-like efficacy of electroconvulsive stimulations in mice, as assessed in the forced swim test. Interestingly, repeated (14 days) administration of sildenafil decreased the anti-immobility action of the electroconvulsive stimulations. In conclusion, the present study shows that sildenafil may alter the effectiveness of antidepressant treatment. Further studies are warranted to better characterize the influence of sildenafil on the activity of antidepressant drugs and electroconvulsive therapy

Математическая модель энергетических процессов в промышленной электрической отвертке

An electric screwdriver was designed to work in an automatic cycle on assembly lines. A characteristic feature of the screwdriver is the use of a low power motor in comparison with commonly used devices. The work of tightening the threaded joint takes place at the expense of the kinetic energy of the components of the drive system and the working screwdriver. It has been proved that the ability of the screwdriver to perform the tightening work is determined by the sum of the mass moment of inertia of the working components system and the mass moment of inertia of the motor's rotor, reduced to the axis of the screwdriver bit. The process of tightening is characterized by the number of screwing pulses, screwing torque values at the end of each pulse and the time of screwing process. The limitation of the value of the transmitted tightening torque takes place through the applied overload coupling.  The construction work of the screwdriver was preceded by the development of a mathematical model of the process of screwing and balance of torques acting during each phase of operation was carried out. This allowed the calculation of the value of the kinetic energy of components of the drive and operating system translated into the tightening work. The kinematic conditions to be met by the screwdriver at the end of a single tightening pulse were determined in order to accumulate kinetic energy and start another tightening pulse.Электрическая отвертка была разработана для автоматической работы на сборочных линиях. Характерной особенностью отвертки является использование двигателя малой мощности по сравнению с обычно применяемыми устройствами. Работа по натяжению резьбового соединения происходит за счет кинетической энергии компонентов системы привода и рабочей отвертки. Доказано, что способность отвертки выполнять затяжные работы определяется суммой массового момента инерции системы рабочих компонентов и массового момента инерции ротора двигателя, приведенного к оси наконечника отвертки. Процесс затягивания характеризуется количеством импульсов завинчивания, значениями момента завинчивания в конце каждого импульса и временем процесса завинчивания. Ограничение величины передаваемого момента затяжки происходит через применяемую перегрузочную муфту. Строительным работам по отвертке предшествовала разработка математической модели процесса завинчивания и балансировки крутящих моментов, действующих на каждом этапе работы. Это позволило рассчитать значение кинетической энергии компонентов привода и операционной системы в переводе на затяжные работы. Кинематические условия, которые должны быть выполнены отверткой в конце одного импульса затяжки, были определены для накопления кинетической энергии и запуска другого импульса затяжки

Antidepressant-like activity of sildenafil following acute and subchronic treatment in the forced swim test in mice : effects of restraint stress and monoamine depletion

Sildenafil is a highly effective oral agent for the treatment of erectile dysfunction of multiple etiologies. Although in clinical practice sildenafil is often used in depressed patients, its influence on the pathophysiology of depression remains unclear. The aim of the present study was to evaluate the antidepressant-like activity following acute and subchronic treatment with sildenafil in naïve mice as well as in mice with reserpine- and restraint stress-induced depressive-like behavior. Since corticosterone is released in response to acute stress, we also aimed to assess the influence of sildenafil on serum corticosterone level in non-stressed and stressed animals. The antidepressant activity of sildenafil was assessed in the forced swim test. Corticosterone serum level was determined by using ELISA method, while brain and serum sildenafil level via HPLC method. Sildenafil administered acutely exerted an antidepressant-like effect. Subchronic (14 days) administration of sildenafil resulted only in a weak antidepressant-like effect when evaluated 24 h after the last dose. Acute but not subchronic sildenafil administration reversed the reserpine- and stress-induced immobility in the forced swim test. The lack of effects of sildenafil after subchronic treatment could have been related to its complete elimination from the brain within 24 h from the last injection. Interestingly, acute administration of sildenafil produced a marked increase in serum corticosterone level in both non-stressed and stressed animals. Sildenafil exerts differential effects in the forced swim test after acute and subchronic administration. Further studies on the antidepressant activity of sildenafil are required

DESIGN AND DYNAMICS MODELING FOR ELECTRIC VEHICLE

This paper descript software for vehicle simulation and mathematical models that describe the motion of the vehicle. A dynamic simulation model of vehicle was developed using Matlab/Simulink and SimDriveline toolbox. The model has a configurable structure that is suitable to simu-lation with multiple levels. The powertrain system model developed using Simulink and SimDrivline could also be used as a generic, modular and fle-xible vehicle modeling platform to support the integration of powertrain design and control system optimization

NUMERICAL ANALYSIS OF ROLLER BEARING

The aim of this paper is to detail the creation of a large tapered roller bearing model with flexible body cages in the Adams program suite for subsequent dynamic analysis and to obtain information about kinematic and dynamic relationships of steel and plastic cages under various operating conditions. The bearing model was made to closely resemble its real-life counterpart, which allows us to estimate load conditions, dynamic conditions of individual bearing parts and interactions between them

MODELING OF FLOW AND TEMPERATURE FIELD IN AN ECONOMIZER

This article deals with the economizer as one of the main parts of a boiler. Economizers and air heaters perform a key function in providing high overall boiler thermal efficiency by recovering the low level energy from the flue gas before it is exhausted to the atmosphere. The most common and reliable economizer design is the bare-tube, in-line, cross-flow type. To reduce capital costs, most boiler manufacturers build economizers with a variety of designs to enhance the controlling gas-side heat transfer rate. From this point of view it creates a lack for an investigation and modeling of these parts