Tunability of terahertz random lasers with temperature based on superconducting materials

We theoretically demonstrate the tunabiltiy of terahertz random lasers composed of high temperature superconductorYBCO and ruby layers as active medium. The considered system is a one-dimensional disordered medium made of ruby grain and YBCO. Finite-difference time domain method is used to calculate the emission spectrum and spatial distribution of electric field at different temperatures. Our numerical results reveal that the superconductor based random lasers exhibit large temperature tunability in the terahertz domain. The emission spectrum is significantly temperature dependent, the number of lasing modes and their intensities increase with decreasing temperature. Also, we make some discussion to explain the reason for the observed tunability and the effect of temperature variation on the spatial distribution of the electric field in the disordered active medium

Study the Robustness Active Filter for a Three-Phase Power Rectifier Considering Line Frequency and Load Variations

ان مغيرات الكترونيات القدرة والتي يكون مبدأ عملها هو التغيير والتقويم تنتج التوافقيات التي تقوم بتشويه موجة الفولتية والتيار لمصدر تجهيز القدرة. عدة بحوث منشورة سعت الى استخدام تقنيات مختلفة لتقليل التوافقيات ومنها:(1- المرشحات الخاملة, 2- مغيرات حقن التيار, 3- المرشحات الفعالة, 4- المرشحات الهجينة). تستخدم المرشحات الفعالة بصورة واسعة مع المقومات ثلاثية الطور لتقليل التوافقيات باستخدام عناصر خاملة مع مفاتيح دوائر الكترونيات القدرة. يتناول هذا البحث خصائص المرشح الفعال عند تغيير تردد المصدر والحمل. حيث لوحظ ان قيمة التشوه التوافقي الكلي THD هي دائما عند الحد المسموح به (اقل من 5%) للمرشح الفعال, اما للمرشح الخامل فأن قيمة THD هي اعلى من 5% وخصوصاً لموجة التيارات عند تغيير تردد المصدر وان المرشح فقط يعمل عند التردد المصمم عنده (50Hz), وايضاً, في حالة تغيير الحمل من الحمل التام الى نصف الحمل فأن استجابة المرشح الفعال يكون اسرع من المرشح الخامل. تم استخدام تقنية المسيطر التخلفي الهستيري لتوليد نبضات المرشح الفعال. نتائج المحاكاة تبين اعلى قيم THD  للتيارات في الحالات: بدون استخدام اي مرشحات، استخدام المرشحات الخاملة واستخدام المرشحات الفعالة هي كالتالي: 24.36% ، 80.79% و 3.03%.Power electronic converters (e.g. AC-DC and DC-AC) produce harmonics which distorting the waveforms of voltage and current. Many research works have examined various techniques to mitigate harmonics at operating conditions (i.e. at a fixed line frequency and a specific load) such as: (i) passive filters, (ii) Current-injection converters, (iii) active filters and (iv) hybrid filters. Active filters are widely used with three-phase bridge rectifiers due to their excellent features for reducing harmonics using power switches instead of passive components that minimize the efficiency of the system. This paper investigates the robustness and the dynamic performance of active filters under the variation of line frequency and DC load. In case of using active filters, it is observed that total harmonic distortion (THD) of voltage and current waveforms is kept at IEEE Standard limits (i.e. less than 5%)  under the variation of line frequency . Whilst the performance of passive filters is highly affected by the variations of line frequency and THD of voltage and current waveforms is always greater than 5% except at designed frequency, i.e. 50 Hz. Moreover the load is changed from full-load to half-load, it is observed that the dynamic response of active filters is faster than passive filters for canceling harmonics. It is worth noting that the hysteresis-current-control method is utilized for adjusting the control pulses of active filters due to its rapid dynamic responsem. Simulation results present the highest values of THD of line currents in cases: without any filters , passive filters and active filters are 24.36%, 80.79% and 3.03%, respectively

Resilience Assessment: A Performance‐Based Importance Measure

The resilience of a system can be considered as a function of its reliability and recoverability. Hence, for effective resilience management, the reliability and recoverability of all components which build up the system need to be identified. After that, their importance should be identified using an appropriate model for future resource allocation. The critical infrastructures are under dynamic stress due to operational conditions. Such stress can significantly affect the recoverability and reliability of a system‘s components, the system configuration, and consequently, the importance of components. Hence, their effect on the developed importance measure needs to be identified and then quantified appropriately. The dynamic operational condition can be modeled using the risk factors. However, in most of the available importance measures, the effect of risk factors has not been addressed properly. In this paper, a reliability importance measure has been used to determine the critical components considering the effect of risk factors. The application of the model has been shown through a case study

Industrial Equipment’s Throughput Capacity Analysis

Throughput capacity (TC) is defined as the total amount of material processed or produced by the system in the given time. In practice, full capacity performance for industrial equipment is impossible because the failures are affected and cause a reduction. Therefore, failure interruptions, especially critical ones (bottlenecks), must be detected and considered in production management. From the point of production view, the bottleneck has the lowest production or performance. Most of the previous works used the availability and related importance measures as performance indicators and prioritization of subsystems. However, these measures cannot consider system production in their prioritization. This paper presents a bottleneck detection framework based on system performance and production capacity integration. The integrated approach is used to assess the loading and hauling subsystems of Golgohar Iron Mine, Iran. As a result of the analysis, the hauling subsystem identifies the system’s bottleneck

Impact of Magnetic Water Irrigation for Improve Growth Parameters of Two Onion Cultivars Allium cepa L.

A field experiment was carried out during 2015-2016 in the Bqubah nursery that belongs to Directorate of Diyala agriculture to study the effect of magnetized irrigation water on growth parameters of two onion cultivars viz. Texas early white 1012 and Texas munerva 1013. The experimental design was split plot with four replications. Results were revealed that significant differences between Texas early white 1012 and Texas munerva 1013, magnetic and non magnetic water and also interaction of two varieties x magnetic and non magnetic water in all tested growth parameters. Texas munerva 1013 was surpassed on Texas early white 1012 and magnetic water was surpassed on non magnetic water in all studied growth parameters such as bulb diameter , Bulb height , Bulb weight without leaves , Number of green leaves and Weight of green leaves. Keywords: Onion, Texas early white 1012, Texas munerva 1013 and magnetic wate

Accounting Readings During the Time of Covid-19

In light of the crisis of the Corona pandemic (COVID 19), the world is witnessing significant and dramatic changes in all levels, trends and sectors, which made this pandemic a justification and a way to rethink many of the topics affected by this misdemeanor, perhaps the most prominent of which is related to the accounting issue, this paper reviews the most important aspects and considerations which is highlighted to highlight the corona's score in accounting