Wave Profile for Breakdown Waves with a Large Current Behind the Wave Front

For analytical solution of breakdown waves with a large current behind the wave front, we employ a one-dimensional, steady-state, three-component (electrons, ions, and neutral particles) fluid model. This project involves breakdown waves propagating in the opposite direction of the electric field force on electrons, anti-force waves (return stroke in lightning); and the electron gas partial pressure is considered to provide the driving force for the propagation of the wave. The basic set of equations consists of the equation of conservation of mass flux, equation of conservation of momentum, equation of conservation of energy, plus Poisson’s equation. The waves are considered to have a shock front. In this study, we examine the possibility and validity of large currents measured and reported by few investigators. Existence of a relationship between wave speed and peak current values is investigated as well. Existence of a large current behind the wave front alters the equation of conservation of energy and Poisson’s equation, as well as the shock boundary condition on electron temperature. Considering a current behind the shock front, we have made appropriate modifications in our set of electron fluid dynamical equations. Using the modified set of equations and the shock condition on electron temperature, we have been able to integrate the set of electron fluid dynamical equations for current bearing anti-force waves. For a range of wave speeds and with the largest current possible for a specific wave speed, we present the wave profile for electric field, electron velocity, and the ionization rate within the dynamical transition region of the wave for anti-force waves

Wave Profile for Anti-force Waves with Maximum Possible Currents

In the theoretical investigation of the electrical breakdown of a gas, we apply a one-dimensional, steady state, constant velocity, three component fluid model and consider the electrons to be the main element in propagation of the wave. The electron gas temperature, and therefore the electron gas partial pressure, is considered to be large enough to provide the driving force. The wave is considered to have a shock front, followed by a thin dynamical transition region. Our set of electron fluid-dynamical equations consists of the equations of conservation of mass, momentum, and energy, plus the Poisson\u27s equation. The set of equations is referred to as the electron fluid dynamical equations; and a successful solution therefor must meet a set of acceptable physical conditions at the trailing edge of the wave. For breakdown waves with a significant current behind the shock front, modifications must be made to the set of electron fluid dynamical equations, as well as the shock condition on electron temperature. Considering existence of current behind the shock front, we have derived the shock condition on electron temperature, and for a set of experimentally measured wave speeds, we have been able to find maximum current values for which solutions to our set of electron velocity, electron temperature, and electron number density within the dynamical transition region of the wave

Wave Profile for Current Bearing Antiforce Waves

For fluid dynamical analysis of breakdown waves, we employ a one-dimensional, three-component (electrons, ions and neutral particles) fluid model to describe a steady-state, ionizing wave propagating counter to strong electric fields. The electron gas temperature and therefore the electron fluid pressure is assumed to be large enough to sustain the wave motion down the discharge tube. Such waves are referred to as antiforce waves. The complete set of equations describing such waves consists of the equations of conservation of mass, momentum and energy coupled with Poisson’s equation. Inclusion of current behind the wave front alters the set of electron fluid dynamical equations and also the boundary condition on electron temperature. For a range of experimentally observed current values, using the modified boundary condition on electron temperature, we have been able to integrate our modified set of electron fluid dynamical equations through the Debye layer. Our solutions meet the expected boundary conditions at the trailing edge of the wave. We present the wave profile for electric field, electron velocity, electron number density and electron temperature within the Debye layer of the wave

Effect of a Self-Management and Follow-Up Program on Self-Efficacy in Patients With Multiple Sclerosis: A Randomized Clinical Trial

Background: Multiple sclerosis (MS) is the most common autoimmune disorder of the central nervous system with profound effects on patients’ independence and self-efficacy. Then, it is still questionable whether self-management programs in patients with MS affect the patients’ self-efficacy. Objectives: The present study aimed to investigate the effect of a self-management program plus regular follow-up on self-efficacy in patients with MS. Patients and Methods: A quasi-experimental study was performed on 80 patients with relapsing remitting MS who were randomly allocated to an intervention (n = 40) and a control group (n = 40). The MS self-efficacy scale was completed before and after the intervention. The intervention group was divided into four small subgroups of ten. Then, each subgroup was invited to participate in four training sessions about self-management. During the two months after the self-management sessions, a weekly telephone follow-up was conducted for each patient in the intervention group. The control group did not receive any intervention other than routine care. Data were analyzed using SPSS 11.5. Descriptive statistics, Chi-square, and independent-samples t-testes were used to analyze the data. Results: No significant difference in mean scores of baseline self-efficacy was found between the control (52.90 ± 8.03) and the intervention groups (54.90 ± 9.51) (P = 0.313). However, a significant difference was observed between the control (50.90 ± 5.71) and the intervention groups (59.80 ± 5.27) regarding mean scores of self-efficacy at the end of the study (P < 0.001). Conclusions: Implementing the self-management program plus regular follow-up increased the perception of self-efficacy in patients with MS. Similar self-management programs are recommended to be integrated in the regular caring of patients with MS

Relationship between the communication skill of nurse - patient with patient safety in the critical care units

زمینه و هدف: تمرکز روی ایمنی بیمار در بخش های مراقبت ویژه موضوعی مهم است و در این بین یکی از مهم ترین عوامل مربوط به ایمنی بیمار، مهارت های ارتباطی بین پرستار و بیمار می باشد. این مطالعه با هدف تعیین رابطه بین مهارت ارتباطی پرستار - بیمار با وضعیت ایمنی بیماران در بخش های ویژه بیمارستان های شهر ارومیه از دیدگاه پرستاران انجام شد. روش بررسی: در این مطالعه توصیفی - همبستگی، 167 پرستار شاغل در بخش های ویژه بیمارستان های آموزشی و غیر آموزشی شهر ارومیه با روش تمام سرشماری شرکت کردند. جهت جمع آوری داده ها از پرسشنامه های روا و پایا شده ی مهارت ارتباطی پرستار - بیمار و وضعیت ایمنی بیمار استفاده شد و مهارت ارتباطی پرستار - بیمار ارزیابی و ارتباط آن با وضعیت ایمنی بیماران تعیین شد. یافته ها: اکثریت پرستاران شاغل در بیمارستان های آموزشی و غیر آموزشی (به ترتیب 5/97 و 8/97 درصد) مهارت ارتباطی خود را در سطح خوب ارزیابی کردند. همچنین 6/87 درصد پرستاران بیمارستان های آموزشی و 8/84 پرستاران بیمارستان های غیر آموزشی ایمنی بیماران را در سطح خوب ارزیابی کردند. بین مهارت ارتباطی پرستاران با وضعیت ایمنی بیماران در بخش ویژه رابطه معنی دار آماری وجود داشت (001/0>P). نتیجه گیری: با توجه به نتایج این مطالعه پرستاران می توانند با بکارگیری مهارت های ارتباطی مناسب با بیماران بستری در بخش های ویژه، ایمنی آن ها را حفظ و ارتقاء بخشند

Effect of IT Application on Project Performance Focusing on the Mediating Role of Organizational Innovation, Knowledge Management and Organizational Capabilities

The purpose of this study is to examine the effect of IT application on project performance focusing on mediating role of organizational innovation, knowledge management and organizational capabilities using SEM. For this purpose, 194 managers, supervisors and experts of software developer companies participated in this study. Participants were asked to complete a questionnaire on each subject. SEM was used to analyze data using the LISREL software. Results are thoroughly discussed in this paper and the findings support the role of IT application, organizational innovation, knowledge management and organizational capabilities on project performance and project benefits

Wave Profile for Current Bearing Lightning Strokes

The propagation of breakdown waves in a gas, which is primarily driven by electron gas pressure, is described by a one-dimensional, steady-state, three-component (electrons, ions, and neutral particles) fluid model. This study will involve waves propagating in the opposite direction of the electric field force on electrons (anti-force waves—lightning return stroke) only. We consider the electron gas partial pressure to be much larger than that of the other species and the waves to have a shock front. Our set of equations consists of the equations of conservation of the flux of mass, momentum, and energy coupled with the Poisson’s equation. The set of equations is referred to as the electron fluid dynamical equations. For breakdown waves with a significant current behind the shock front, the set of electron fluid dynamical equations and also the boundary condition on electron temperature need to be modified. For a range of experimentally measured current values and a range of possible wave speeds, we will present the method of solution of the set of electron fluid dynamical equations and also the wave profile for electric field, electron velocity, electron temperature, and number density, as well as the ionization rate within the dynamical transition region of the wave

Prevalence of vitamin d deficiency in people aged 18 old referred to Yasuj lab in winter of 2017

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Survey of Insulation Systems in Electrical Machines

Insulating materials and insulation systems design have been gaining more attentions as more electrical machines tend to operate in harsher environments for various applications. Harsh environments include high temperature, humidity, erosion, low air pressure, etc. This paper discusses recent advances in insulation systems for electrical machines. Insulation tests as well as test standards that have been used to evaluate insulation systems and detect insulation failures will be discussed. Insulating materials used for a wide range of industrial applications such as wind turbine generators, aerospace hybrid/electric powertrain, and hydro generators have been summarized. For the emerging high-altitude, highvoltage aerospace applications, partial discharge and its impact on insulation systems will be discussed. Finally, polymer nanocomposite materials with excellent thermal conductivity and dielectric strength are highlighted as an outlook

Microencapsulation of saffron petal anthocyanins with cress seed gum compared with Arabic gum through freeze drying

In this research, encapsulation efficiency of cress seed gum (CSG) as a native hydrocolloid was compared with Arabic gum (AG) and maltodextrin (dextrose equivalent of 20 (M20), and 7 (M7)) for saffron (Crocus sativus) petal's extract by freeze drying method. Combinations of CSG-M20, AG-M20, and M7-M20 with ratios of 50:50 and M20 alone (100%) were used as wall materials. A mixture of 1:5 (based on dry matter) between core (concentrated anthocyanin extract of saffron petal) and wall materials were freeze dried and stability of encapsulated anthocyanins along with color parameters (a∗, b∗, L∗, C, H° and TCD) of final powders were measured during 10 weeks of storage (at 35 °C as an accelerated method). Total anthocyanins were determined through pH differential method every week. Four prepared formulations of encapsulated powders didn't show any significant differences (P > 0.01) in terms of total anthocyanin content measured immediately after production and after 10 weeks storage. AG-M20 mixture and M20 alone showed the highest and lowest TCD, respectively. The mixture of CSG-M20 in comparison with AG-M20 and M20 had the same protecting effect (P < 0.01) but showed a relatively high TCD (9.33). © 2015 Elsevier Ltd. All rights reserved