Динамическая модель тепломассообменных процессов в камере форсуночного увлажнения

Розглядається математичне моделювання динамічних процесів тепло- та масообміну для камери форсуночного зволоження, яка використовується в системах штучного мікроклімату для охолодження та адіабатного зволоження повітря. На основі рівнянь матеріального та теплового балансів отримано три рівноцінні моделі: у вигляді системи диференційних рівнянь; у просторі стану; у вигляді передатних функцій, які дозволяють проводити моделювання перехідних процесів у камері форсуночного зволоження за основними каналами впливу. Запропоновані математичні залежності зручно реалізувати у середовищі MatLAB. Приведено приклад моделювання перехідних процесів для форсуночного зволожувача промислового кондиціонера КЦКП-80, який виготовляється компанією ВЕЗА. Динамічна модель форсуночного зволожувача може використовуватися спеціалістами із автоматизації для аналізу та налаштуванню параметрів систем керування промислових кондиціонерів.Mathematical modeling of dynamic processes heat-mass exchange for a chamber of the sprayer moistening which is used in systems of an artificial microclimate for cooling and for the adiabatic moistening of air is observed. On the basis of the equations of material and thermal balance three equivalent models: in the form of systems of differential equations; state space; in the form of transfer functions, which allow to spend modeling of transients in a chamber of the sprayer moistening on the basic channels of influence are gained. Sampling of dynamic model is defined by methods of a control system synthesis of the industrial air conditioner and tastes of researcher. For raise of accuracy of mathematical calculations in paper experimental definition of factors heat-mass exchange which allows adapting dynamic model for concrete operating conditions of a chamber of the sprayer moistening is offered. The offered mathematical dependences are conveniently realized in the environment of Matlab. The instance of modeling of transients for sprayer humectants of air conditioner KCKP-80, which is manufactured by company VEZA is resulted. The gained transients have aperiodic character without delay. The analysis of transients after the possible channels of adjusting confirmed their high inertance, that is why during automation of industrial conditioners it follows to give up regulative influences in the chamber of the moistening after the change of temperature and expense of water on moistening. The dynamic model of sprayer humectants can be used by specialists on automation for the analysis and adjustment of parameters of control systems of industrial air conditioners.Рассматривается математическое моделирование динамических процессов тепло- и массообмена для камеры форсуночного увлажнения, которая используется в системах искусственного микроклимата. На основании уравнений материального и теплового балансов получено три равноценные модели: в виде системы дифференциальных уравнений; в пространстве состояний; в виде передаточных функций, которые позволяют провести моделирование переходных процессов в камере форсуночного увлажнения по основным каналам влияния. Предложенные математические зависимости удобно реализовывать в среде MatLAB. Приведен пример моделирования переходных процессов для форсуночного увлажнителя промышленного кондиционера КЦКП-80, который изготавливается компанией ВЕЗА. Динамическая модель форсуночного увлажнителя может использоваться специалистами по автоматизации для анализа и настройки параметров систем управления промышленными кондиционерами

Resistance effects due to magnetic guiding orbits

The Hall and magnetoresistance of a two dimensional electron gas subjected to a magnetic field barrier parallel to the current direction is studied as function of the applied perpendicular magnetic field. The recent experimental results of Nogaret {\em et al.} [Phys. Rev. Lett. {\bf 84}, 2231 (2000)] for the magneto- and Hall resistance are explained using a semi-classical theory based on the Landauer-B\"{u}ttiker formula. The observed positive magnetoresistance peak is explained as due to a competition between a decrease of the number of conducting channels as a result of the growing magnetic field, from the fringe field of the ferromagnetic stripe as it becomes magnetized, and the disappearance of snake orbits and the subsequent appearance of cycloidlike orbits.Comment: 7 pages, 7 figure

36. A prospective, randomized study to compare the value of two fractionation schemes of palliative radiotherapy for inoperable non-small cell lung cancer

A prospective, randomized study was conducted in eight Polish institutions to compare the value of two fractionation schemes of palliative radiotherapy for inoperable non-small cell lung cancer. Assessed was the impact of either treatment on the degree and duration of relief of tumor-related symptoms and on patient's performance status. Secondary endpoints included treatment side-effects, objective response and overall survival. One hundred patients were randomly assigned to the dose of 20 Gy/5×/5 days (Arm A) or 16 Gy/2×/8 days (Arm B). There were 90 men and 10 women aged between 47 and 79 (mean 66). Eighty four patients had locally advanced tumor and 16 patients had metastatic disease. Squamous cell carcinoma was diagnosed in 65 patients, adenocarcinoma – in 9 patients, large cell carcinoma – in 1 patient and unspecified non-small cell carcinoma – in 25 patients. Fifty five patients were assigned to Arm A and 45 – to Arm B. Ninety eight patients received assigned treatment whereas two patients died before the end of treatment. The final results of the study will be presented at the conference

A cost-effectiveness analysis of a preventive exercise program for patients with advanced head and neck cancer treated with concomitant chemo-radiotherapy

In recent years, concomitant chemo-radiotherapy (CCRT) has become an indispensable organ preserving treatment modality for advanced head and neck cancer, improving local control and overall survival in several anatomical sites [1]. Unfortunately, CCRT can have a detrimental effect on many functions of the upper respiratory and digestive system. Sequellae such as pain, oedema, xerostomia and fibrosis negatively affect mouth opening (trismus), chewing, swallowing and speech [1]. Several studies investigating long-term effects of CCRT have concluded that swallowing and nutritional dysfunction tend to be persistent and can be severe [2-4]. Not surprisingly, therefore, CCRT can have a negative effect on patients‟ quality of life (QoL) [2]. Moreover, even before onset of treatment patients may already present with pain, impaired swallowing, trismus, aspiration, dietary restrictions and tube dependency, and loss of body weight, because the tumour may disrupt the normal anatomy and thus interfere with normal function [1]. Many studies refer to the importance of rehabilitation after, and even during treatment, in order to support and improve those functions [2]. However, as yet, few studies have investigated the effects of (preventive) rehabilitation exercises on the predictable and inevitable swallowing and mouth opening problems for this patient group. In addition, little is known about the costs and benefits of such exercise programs for head and neck cancer. As the clinical effectiveness is established [4], it is now relevant to embark on cost-effectiveness as a contribution to decision making on coverage. The aim of this study was to analyze the incremental cost-effectiveness for a preventive exercise program (PREP) versus usual care (UC) for patients with advanced head and neck cancer treated at the Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital (NKI-AVL)

Doświadczalna i numeryczna analiza niezatopionego wypływu spod zasuwy

The problem of sluice gate flow is analyzed using two models: a simplified one, derived according to the concept of the Potential Field (PF), and a more complex form, based on the Reynolds Average Navier-Stokes (RANS) equations. The numerical solution is compared with experimental data, including measurements performed by authors and results acquired from literature. Despite its simplicity, the PF model provides a satisfactory agreement with the measurements. The slightly worse performance of the RANS model comes from an overestimation of energy losses.Niezatopiony wypływ wody spod zasuwy opisano dwoma modelami: uproszczonym, wyprowadzonym na podstawie teorii płaskiego przepływu potencjalnego (PF), i modelem o większym stopniu złożoności, bazującym na uśrednieniu Reynoldsa równań Naviera-Stokesa (RANS). Wyniki obliczeń przepustowości scharakteryzowano współczynnikami wydatku i porównano z wynikami własnych pomiarów hydraulicznych oraz podawanymi w literaturze. Współczynniki wydatku uzyskane z modelu PF są zbliżone do wyników badań eksperymentalnych. Nieco większe różnice wartości współczynników wydatku uzyskano z obliczeń modelem RANS. Wynika to z przeszacowania strat energii strumienia wody