Effects of cryopreservation on performance and fertilizing ability of sperm from Kerai (Puntius daruphani)

Puntius daruphani broodstocks bought from fishermen in Temerloh, Pahang, conditioned in the Hatchery Unit of Universiti Putra Malaysia were used for all the experiments. In this study fresh and cryopreserved sperm of P. daruphani were analyzed for their physical characteristics (motility, motile period, live sperm count and abnormality), morphology, fertilizing ability and hatching rate. Kurokura medium and dimethyl sulfoxide (DMSO) were used as extender and cryoprotectant, respectively in the cryopreservation of the sperm. The percentage of motility, live sperm count and time of motile period after activation of frozen-thawed sperm were significantly lower than that of fresh sperm. Whereas the percentage of abnormality for frozen-thawed sperm was significantly higher than fresh sperm. ANOVA showed that there was no significant different (p>0.05) between fresh samples for all the parameters, whereas results among frozen-thawed samples using different concentrations of DMSO (10 - 15%) were significantly different (p0.05) among frozen-thawed samples. The entire testis with total length ranged from 9.8 to 11.3cm, were categorized as the anterior, middle and posterior parts. The anterior, middle and posterior parts were creamy in colour and having soft tissue. Anterior and middle parts involved in the production of spermatozoa. Posterior part as glandular testis is only displayed some ducts with smooth muscle layer and produce seminal fluids. P. daruphani sperm consisted from three parts head, midpice and flagellum, measuring 2.19±0.01, 0.955±0.02 and 17.08±0.05 μm respectively. In the first experiment, the results on the physical characteristics (motile period, motility, abnormality and live sperm count) were significantly different (p0.05) between the cryopreserved sperm samples of 1 and 3-month for all the parameters above. However, there were significant different (p<0.05) for all the physical characteristics (motile period, motility, abnormality and live sperm count) between cryopreserved (1 and 3 month) sperm samples using 10 and 15% DMSO. These results are supported by the observation on the sperm morphology showing that by using 15% DMSO produced less damages on the sperm membrane, cytoplasmic mitochondria and flagellum as compared to 10% DMSO

Evaluating the impact of superconducting fault current limiters on distribution network protection schemes

Rising fault levels are becoming increasingly problematic in the UK distribution network, with large sections of the network operating near to its designed fault level capability. With the increase in penetration of distributed generation that is expected in the coming years, this situation is becoming more pressing. Traditional methods of dealing with the issue may not be appropriate - upgrading plant is expensive and disruptive, while network reconfiguration can compromise security of supply. Superconducting Fault Current Limiters (SFCLs) are emerging as a potential solution, with installations now taking place in several locations worldwide. The integration of an SFCL into a network involves a number of challenges, particularly concerning the coordination of protection systems. The operation of existing protection schemes may be compromised due to the increased resistance in the network during a fault (in the case of a resistive SFCL). Furthermore, the reduction in fault levels, although desirable, can have a detrimental impact on protection operating times. This paper will consider an existing medium voltage network in the UK, which incorporates distributed generation capacity. The performance of IDMT overcurrent and distance protection schemes will be examined when an SFCL is installed in this network. In particular, the increased operating time of overcurrent relays will be discussed along with grading implications. The impact on distance protection reach will also be examined. A variety of network operational scenarios including SFCL placement and fault conditions will be considered and compared. Recommendations will be made in terms of protection settings and SFCL placement in order to mitigate the aforementioned issues

A novel fault let-through energy based fault location for LVDC distribution networks

Low Voltage Direct Current (LVDC) distribution systems have recently been considered as an alternative approach to electrical system infrastructure as they provide the additional flexibility and controllability required to facilitate the integration of more low carbon technologies (LCTs). However, DC protection systems and, more specifically high accuracy DC fault location, have been recognised as a key challenge to facilitating post-fault network maintenance. Most of the existing fault location techniques rely on current derivative or communications-based methods that are either very sensitive to noise, or require a high level of data synchronisation. Fault energy has been recognized as a reliable indicator of more accurate fault location estimations. Therefore, this paper develops a mathematical model for describing fault energy during the transient period of DC faults. The method subsequently proposes a new fault let-through energy based DC fault location working strategy to facilitate post-fault network maintenance. The proposed method does not require data synchronisation regardless of the voltage, current, and the size of the converters connected to the LVDC feeder. The capabilities of the proposed fault location strategy are validated against different faults applied on an LVDC test network in PSCAD/EMTDC and shown to be more reliable and accurate than existing methods

Feasibility of direct current street lighting & integrated electric vehicle charging points

In the context of the energy trilemma (the provision of sustainable, affordable, reliable energy) the application of Low Voltage Direct Current (LVDC) distribution offers several advantages over the incumbent AC distribution system. LVDC distribution can increase the power transfer capability of existing cable assets while reducing the converter complexities required to integrate distributed generators and modern electrical loads to the network. This paper evaluates the technical potential for LVDC street lighting and integrated electric vehicle charging points by considering existing cable specifications, protection schemes and overall system efficiency. The first author was supported by EPSRC Centre for Doctoral Training in Future Power Networks and Smart Grids (EP/L015471/1) with industry support from Rolls-Royce plc. No new data was collected or generated during the course of the research

Validation of fast and selective protection scheme for an LVDC distribution network

Low Voltage Direct Current (LVDC) distribution systems are one of the emerging technologies to recently attract attention for more efficient use of energy, and wider uptake of distributed renewables and energy storage. They do however present significant fault protection and safety challenges, which are not possible to address without using advanced protection techniques. Therefore, this paper considerably reviews these key challenges, and presents experimental results of prototyping an advanced protection scheme developed to help enable LVDC distribution networks for utility applications. The developed scheme is a DC current direction-based using multiple intelligent electronic devices (IEDs) relays in combination with controllable solid-state circuit breakers to detect and locate DC faults, and provide selective protection tripping within sub-millisecond timescales. A scaled laboratory demonstrator that emulates an LVDC distribution network is used as a test platform. It allows the characterisation of the transient behaviour for various fault conditions and locations. The developed protection algorithm is implemented in LabVIEW, and its performance against such fault conditions is tested within this environment

A co-simulation approach using powerfactory and matlab/simulink to enable validation of distributed control concepts within future power systems

In power network analysis it is increasingly desirable to implement controller and power systems models within different software environments. This stems from, among other things, an increasing influence of new and distrib-uted control functions within smart grids and a growing influence of market operations. The computation time re-sulting from use of multiple simulation environments can cause significant delays and constrain the number of scenarios considered. This paper introduces and com-pares several techniques for integrating external control system models into power systems models for time do-main simulations. In particular, a new technique is reported in this paper for PowerFactory-MATLAB/Simulink co-simulation interfaces, which offers a significant advantage over alternative methods in terms of the reduction in simulation runtimes and flexi-bility for the end user

استراتيجيات تطبيق إدارة الجودة في جامعة مولانا مالك إبراهيم الحكومية الإسلامية، وأسس الاعتراف وأعتماد المؤهلات العلمية في مركز ضمان الجودة بليبيا

تهدف هذه الورقة البحثية إلى معرفة معايير الجودة في الجامعة، وكيفية تطبيق الجودة بالجامعة، وأسس الاعتراف وأعتماد المؤهلات العلمية في ليبيا. وخلص الباحثين إلى عدة نتائج وتوصيات نذكر منها أهم النتائج : تنقسم معايير الجودة في جامعة مولانا مالك إبراهيم الحكومية الإسلامية- مالانج إلى: 1) المعايير الأكاديمية: و تنقسم إلى: أ). معايير عامة: وتشمل الرؤية، المهمة (رسالة الجامعة)، الغرض، شكل القيادة ( الإدارة)، الخطة الاستراتيجية. ب) معايير التربية والتعليم. ت). معايير البحوث. ث) معيار خدمة المجتمع. 2) معيار الحد الأدنى من الخدمة الاكاديمية (SPM) : ويصنف إلى: أ‌) معيار رضا أصحاب المصلحة، ب‌) معيار الإدارة، ت‌) معيار عملية التعليم والتنمية، ث‌) معايير تنمية روح وثقافة العمل. ويمر تطبيق الجودة بالجامعة بالمراحل التالية: مرحلة التزام رئاسة الجامعة بتطبيق برنامج الجودة ودعمه، مرحلة وضع ورؤية استراتيجية واضحة ، مرحلة تشكيل مجلس للجودة بالجامعة، مرحلة تكوين إستراتيجية لإدارة الجودة، مرحلة أجتماع مجلس الجامعة لآتخاذ قرار حول مجال تطبيق برنامج الجودة، مرحلة تحديد وترتيب الاحتياجات التدريبية للمدراء على مفاهيم الجودة، مرحلة التأكد من مدى مطابقة الخدمات المنتجة مع إحتياجات المستفيدين، مرحلة إدخال وتطبيق برنامج الجودة في الهيكل التنظيمي للجامعة، مرحلة مراقبة وتقويم النتائج لتحقيق التحسين والتطوير، ومرحلة الاعلان عن نجاح برنامج الجودة ومكافأة المشاركين فيه. وأسس الاعتراف وأعتماد المؤهلات العلمية في ليبيا، تتلخص في أن المركز الوطني لضمان الجودة واعتماد المؤسسات التعليمية والتدريبية هو الجهة الوحيدة المخولة بإعتماد ومعادلة المؤهلات العلمية في ليبيا. و جامعة مولانا مالك إبراهيم الحكومية الإسلامية- مالانج، أحدى الجامعات العالمية المعترف بها من قبل المركز الوطني لضمان الجودة واعتماد المؤسسات التعليمية والتدريبية في ليبيا لمطابقتها للبرامج والمواصفات القياسية العالمية للجودة. ومن استراتيجيات الجامعة لتحقيق الجودة العالمية فإنها تعمل على تقديم الخدمة الأكاديمية في التعليم والتعلم والبحث العلمي والخدمة الإجتماعية بناءاً على هيئة تقويم الجامعات الوطني (BAN-PT) والعالمي (ISO 9001:2000)

Improved voltage-based protection scheme for an LVDC distribution network interfaced by a solid state smart transformer

The increasing electrification of transport and heat will place increasing demand on low voltage (LV) networks with the potential to overload medium voltage (MV)/LV transformers and LV cables. Deployment of a solid-state transformer (SST) at MV/LV substations and using LV direct current (LVDC) distribution systems offer great potential to address such challenges. However, the SST deployment in addition to the introduction of LVDC will fundamentally change LV fault behaviour and protection requirements due to the limited short-circuit capabilities of such technologies. The SST will deliver limited fault currents, making current-based protection (widely used in LV networks) less reliable. Therefore, this study presents an advanced communication-less protection scheme which can effectively detect and locate DC faults even with reduced fault levels. The developed protection scheme overcomes the selectivity limitations in LVDC voltage-based protection solutions by using a combination of DC voltage magnitude, voltage concavity (sign of d2v/dt2) and the sign of the rate of change of current (di/dt) regardless of the current magnitudes. The credibility of the developed protection algorithm is tested against different fault scenarios applied on an active LVDC network model built in PSCAD/EMTDC. Noise signals have been included in the simulation to appraise the resilience of the developed scheme

Cyber-physical energy systems modeling, test specification, and co-simulation based testing

The gradual deployment of intelligent and coordinated devices in the electrical power system needs careful investigation of the interactions between the various domains involved. Especially due to the coupling between ICT and power systems a holistic approach for testing and validating is required. Taking existing (quasi-) standardised smart grid system and test specification methods as a starting point, we are developing a holistic testing and validation approach that allows a very flexible way of assessing the system level aspects by various types of experiments (including virtual, real, and mixed lab settings). This paper describes the formal holistic test case specification method and applies it to a particular co-simulation experimental setup. The various building blocks of such a simulation (i.e., FMI, mosaik, domain-specific simulation federates) are covered in more detail. The presented method addresses most modeling and specification challenges in cyber-physical energy systems and is extensible for future additions such as uncertainty quantification

An advanced protection scheme for enabling an LVDC last mile distribution network

Low voltage direct current (LVDC) distribution systems have the potential to support future realisation of smart grids and enabling of increased penetration of distributed renewables, electric vehicles, and heat pumps. They do however present significant protection challenges that existing schemes based on DC fuses and conventional electro-mechanical circuit breakers (EMCBs) cannot manage due to the nature of DC faults and slow device performance. Therefore, this paper presents an advanced protection scheme that addresses the outstanding challenges for protecting an LVDC last mile distribution network. The scheme takes advantage of advanced local measurements and communications that will be naturally integrated in smart grids, and the excellent level of controllability of solid state circuit breakers. It thus provides fast DC fault detection and interruption during DC transient periods in addition to achieving fault limitation and fast reliable restoration. The introductory part of the paper quantifies the potential benefits of LVDC last mile distribution networks, and discusses the potential LVDC architectures that best utilise the existing plant. Based on the new LVDC architectures, a typical UK LV network is energised using DC and modelled, and used as a case study for investigating the protection issues and evaluating the new protection scheme performance through simulation