Search

This article aims to describe the transformation of the knowledge process, namely the gambyok site into an indicator of mathematics learning tools with a Pancasila student profile. The research used is descriptive qualitative research. The instrument is an interview sheet that is used to gather information from cultural actors, mathematical concepts, learning outcomes and learning objectives (ATP). Transformation process data obtained from interviews with informants, cultural actors studied by collecting information by translating interview scripts, data reduction by classifying information that is relevant to what is needed in such a way that the transformation process variables can apply to the indicators indicator . The results shown in this article are indicators that can be used to develop mathematics learning tools with a Pancasila student profile.

It can be expected that the power systems of the future will be significantly different from today's, especially due to increasing renewable energy sources (RESs), storage systems, and price-responsive users leading to large uncertainty and complexity. The operation of these future grids (FGs) at levels of renewable energy approaching 100% will require all the usual stability analysis along with new issues in a much more complex situation than has been encountered in the past. In fact, how close we can get to this desired level will likely be dependent on the assessed stability limits. Therefore, in this study, we use a novel scenario-sensitivity-contingency based framework to evaluate the system stability along possible evolution pathways towards high renewable FGs. As a case study, we carry out our studies based on proposed future scenarios and sensitivities for the Australian FG. Using a simulation platform that encompasses market simulation, load flow calculation and stability assessment altogether, the impact of grid strength, level of prosumers, and utility storage on the stability of the FG is studied and quantified indices for long term stability have been devised. The results of this study enable us to address the underlying stability issues of the FGs.

The objective of this study was to evaluate the impact of hydrothermal pretreatment of source separated organics (SSO) and thickened waste activated sludge (TWAS) on the solubilization and biomethane production. The feedstocks went through 15 different conditions in a wide range of temperature (150-240°C), retention time (5-30) min and severity indexes (3-5). The result of the study revealed that the effect of hydrothermal pretreatment can vary based on the feedstock primary properties and the optimum pretreatment condition. In this study, the optimum pretreatment conditions for highest solubilization and solid reduction of the SSO were 220°C and 10 minutes retention time, however, for highest methane production, it was 190°C for 20 minutes. In case of TWAS, the result revealed that the maximum biomethane production was achieved at pretreatment conditions of 160°C and 20 min, while, the highest solubilization and solid reduction was observed in 220°C and 10 minutes retention time.

This study evaluated the impact of hydrothermal pretreatment on thickened waste activated sludge (TWAS) for solubilization enhancement and biomethane production improvement through the mesophilic anaerobic digestion process. In order to assess the effect of temperature, retention time and severity index (SI) of the hydrothermal pretreatment, TWAS was exposed to fifteen different pretreatment conditions within a combination of 10 different pretreatment temperature range (150–240 °C), five different retention times (5–30 min) and five different severity indexes (SI = 3, 3.5, 4, 4.5 and 5). The solubilization enhancement was observed in all hydrothermally pretreated samples with the highest solubilization efficiency of 49% in pretreatment conditions of 200 °C and 10 min retention time within the corresponding SI = 4. Biomethane production was not improved in all fifteen pretreatment conditions, pretreatment with SI beyond 4 decreased the biodegradability of TWAS. The highest biomethane production was observed in the pretreatment condition of 170 °C and 10 min with a 40% increase compared to non-pretreated TWAS.

The use of wastewater (urine) as a fertilizer was shown to potentially reduce the campus wastewater load and contribute to saving in expensive wastewater treatment, while dealing with it as valuable resource. If one assumed that this wastewater fertilizer (arguably, one of the best agriculturally acknowledged fertilizers), was applied at odor appropriate and physiologically sustainable rates (Nitrogen Loading Rate (NLR) of up to 0.73 g N m-2 week-1 equivalent to 104.28 mL urine m-2 week-1 applied for 16 weeks) and considered total available area for potential green walls, it could be stated that the entire urine stream generated daily on campus (varying from 2.2 to 4.5 m3) could be accommodated on campus green walls as a valuable resource with significant benefits. In the studies on monitored plant physiological parameters under various conditions, it was observed that urine fertilizer positively affected to the food production, inflorescences and health of butterfly pea (Clitoria ternatea) plant as well as could say that it was the most suitable plant for green wall. Further integration of urban wastewater management and agriculture (urban food production) into this scenario can make it even more attractive and economically sustainable.

High penetration of distributed generation (DG) is mainly constrained by voltage-related issues. Due to the uncertainties associated with type, size, and location of DGs, it is difficult to quantify their integration limits in distribution networks, i.e., hosting capacity (HC). To address this issue, this paper proposes a probabilistic-based framework to determine the maximum integration limits of DGs considering the voltage rise and voltage deviation constraints. Such framework requires the use of the HC model, which can be formulated as a nonlinear optimization problem. Adding the voltage deviation constraint in the HC problem makes the model unsolvable. We address this issue by proposing a two-step algorithm to linearize the HC model. Then, using the linearized model, a probabilistic framework is proposed for considering the load variability and DGs uncertainties. To validate the efficacy and accuracy of the proposed framework, we identify the HC of a balanced and an unbalanced distribution networks and compare our results with those obtained from comprehensive power flow method and the traditional conservative planning. Finally, using the proposed framework, the impact of voltage deviation constraint, load growth, DG type and network structure on the HC are comprehensively studied using different DG technologies (i.e., Photovoltaics and wind).

Defect detection is a crucial issue at industrial level, and generally, the designers have to find out a way to select suitable features to detect the defects in textured material images. This work reports this issue using the gray-level co-occurrence matrix (GLCM) and Gabor filter texture segmentation. We first analyze the defects in the corresponding tyre texture images using GLCM and then we apply Gabor filter texture segmentation to illustrate further the impurities found in the material. Our proposed method matches the abnormal textured images with standard texture images, and we use the 5 GLCM features to calculate the score for an abnormal texture image. Further, our proposed method decides the defected tyres and presents the texture segmentation of abnormal image. We found that our proposed method performs well when compares with other methods of tyre images data.

The present paper highlights the experimentation procedure and decomposition of vehicle tyres through the extensive technique of radiography by the incorporation of total changes occurring in the image, transformation of curvelet that is based on image enlargement, and moreover, canny edge detection will examine the patterns through outer surfaces and poor defects in different types of tyres. Keeping into knowledge, the feature appeared after proceeding radiography are decomposed into pattern recognition. In the present paper, the splitting of the tyre into various segments of pattern recognition through image processing is focused on the clear image for selection to detect defects. It is done because the images occurred in the form of segments and recognition to detect the defects in continuity becomes simpler. Suitable modifications is made around the corners of the image appeared and is enhanced by the help of curvelet coefficients initially before the image detection algorithm is carried out. In addition, the result of the analysis is also drawn by incorporating the method of detection called, canny edge and is helpful for the detection of abnormal textures. Moreover, the operator of Sobel and many other detection methods like canny edge algorithms are effective for making comparative and precise discussion on the results of the analysis in brief. It is indicated by the results of analysis through X-ray detection method that outer surfaces of tyre and weak defects inside the tyres are the two different types of detection procedures located clearly by the help of proposed methods.

The increasing penetration of nonsynchronous renewable energy sources (NS-RES) and demand side-technologies alter the dynamic characteristics, and particularly, the frequency behavior of a power system. Given this, we propose a framework for assessing renewable integration limits concerning power system frequency performance using a time-series scenario based approach. By considering a large number of future scenarios and their sensitivities with respect to different parameters, we can identify maximum nonsynchronous instantaneous penetration limits for a wide range of possible scenarios. Further, we derive a dynamic inertia constraint and incorporate it into the market dispatch model to reduce the detrimental impacts of high NS-RES penetration on the frequency performance. The results using the Australian future grid as a test case show that such an explicit inertia constraint ensures power system frequency stability for all credible contingencies. To improve the frequency performance, we assess and quantify the contribution of a wide range of technologies, including synchronous condensers, synthetic inertia from wind farms and a governor-like response from de-loaded wind farms. The results show that the last option is the most effective one.

This paper proposes a coordinated wind farm (WF) operation strategy that exploits the wake interaction within a WF. In contrast to the conventional WF operation strategy where each wind turbine (WT) is optimized individually, three operation strategies are suggested: 1) maximization of the WF's power while maintaining WF's rotational kinetic energy; 2) maximization of the WF's rotational kinetic energy while maintaining WF's output power; and 3) a de-loaded strategy whereby the WF's rotational kinetic energy is maximized for a fixed de-loading margin. The three operation strategies are formulated as nonlinear optimization problems and solved in a central WF controller. The optimal rotor speeds and pitch angles are used as reference values in the individual WTs. The optimization results for the three respective operation strategies show that: 1) up to 3% increase in the WF's output power; 2) up to 23% increase in the WF's rotational kinetic energy; and 3) up to 28% increase in the WF's rotational kinetic energy and 8% reserve power while operating the WF in a 5% de-loaded mode with respect to the conventional operation strategy. Time-domain simulations show that the proposed operation strategy noticeably improves the WF's performance in frequency control.

High penetration of non-synchronous generation from increased competition by renewable energy generators alters the dynamic behavior, namely, the frequency performance of a power system. Given this, it is important to identify a minimum level of synchronous generation where system frequency performance is satisfactory. To address this issue, in this paper we develop, calibrate and simulate a load frequency control model of a power system, using the Australian National Electricity Market (NEM) as a case study. The minimum inertia requirements to satisfy frequency operating standards, i.e., rate of change of frequency limits and frequency nadir were determined for a variety of single and multiple contingency scenarios. The study determines that a certain inertia level must always be sustained to meet the system security criteria. Simulation results show that the NEM system should always maintain at least 28.3% of the network’s current inertia capacity to ensure optimal frequency regulation and power system security.

Nodes can connect with each other to form a self-organizing, infrastructure-less, wireless ad-hoc network, in which every node performs the actions of both host and router. The demand for wireless ad-hoc networks is growing because of their simple and quick installation. However, the limited power of nodes and continuously changing topologies of wireless networks adversely affect the performance of wireless ad-hoc networks. A major problem is maximizing the lifetime of wireless networks while ensuring that packets are delivered to their destinations. Much research has been published on the routing protocols of wireless ad-hoc networks, but most of the algorithms focus on a single performance metric of wireless networks. In this chapter, we propose a routing protocol referred to as DEAR-2 for a heterogeneous wireless ad-hoc network. We have embedded the energy and device type awareness features of the Device and Energy Aware Routing (DEAR) routing algorithm in the face routing algorithm, which focuses only on guaranteed delivery.

تهدف هذه الدراسة إلى تقويم دور بورصة سوق السلع الماليزية في إصلاح العمليات المالية القائمة على التورق المصرفي المنظم؛ وذلك من خلال بيان نبذة مختصرة عن التورق الفردي والتورق المصرفي المنظم وآراء العلماء فيهما مع ذكر أهم الإشكالات الشرعية التي حرمت لأجلها المجامع الفقهية وبعض الهيئات الشرعية وجمهور العلماء المعاصرين التورق المصرفي المنظم الذي يجرى في السلع الدولية عبر بورصات عالمية وغيرها؛ والتي منها: أ- وهمية السلع المستخدمة في عملية التورق وعدم وجودها، ب- إعادة عمليات التورق على سلعة واحدة دون تغيير مكانها، ج- سيطرة الصورية على التعاملات، د- عدم إمكانية قبض السلعة، ه- وجود التواطؤ المحظور في المعاملة، وغيرها. ثم البيان والتقويم للدور الذي تلعبه بورصة سوق السلع الماليزية لأجل تجنب تلك الإشكالات الشرعية المذكورة في عمليات التورق المصرفي. ويستخدم في البحث المنهج الوصفي والتحليلي والمقارن؛ وذلك بوصف موجز عن التورق الفردي والتورق المصرفي المنظم والإشكالات الشرعية في تطبيقات الأخير، وتعريف عام عن بورصة سوق السلع الماليزية وبيان الآلية المستخدمة لإجراء التورق المصرفي فيها، مع التحلیل والتقويم للدور الذي تلعبه بورصة سوق السلع في إصلاح التورق المصرفي ومقارنته مع عمليات التورق في البورصات والأماكن الأخرى. فيشتمل البحث على مقدمة وثلاثة مباحث وخاتمة؛ المبحث الأول يكون نبذة مختصرة عن التورق الفقهي والتورق المصرفي المنظم وآراء العلماء فيهما والإشكالات التي ترد على تطبيقات الأخير، وأما المبحث الثاني، فيكون في تعريف بورصة سوق السلع الماليزية وطريقة عمليات التورق فيها، وأما المبحث الثالث، فيكون عن تقويم دور بورصة سوق السلع الماليزية في إصلاح تطبيقات التورق المصرفي المنظم وأما الخاتمة، فتشتمل على نتائج البحث. فتوصل البحث إلى أن عمليات التورق المصرفي عن طريق بورصة سوق السلع الماليزية أحسن وأفضل من كثير عمليات التورق الرائجة في العالم -عند من يرى من العلماء جواز التورق المصرفي-، وأنها إصلاح لبعض الجوانب المهمة مثل التأكيد من وجود السلعة وعدم إعادة السلعة للتعاملات مرة أخرى وأن يكون التعاملات حقيقية لا صورية، ولكنه رغم ذلك، فهي ليست الهدف المنشود الذي يسعى العلماء والباحثون إلى تحقيقه في التورق، لأن بعض الإشكالات الشرعية لا زالت قائمة في أمر الصورية وقبض السلعة واحتمال وجود التواطؤ في رجوع السلعة إلى بائعها الأول، ثم توصيات واقتراحات من الباحثين لرفع الإشكالات المذكورة.

Integration limits of distributed generations (DGs) in distribution networks, i.e. the hosting capacity (HC), are highly dependent on uncertainties associated with the size, location and output power of DGs. Addressing these uncertainties to a great extent is reliant on the availability and resolution of the historical data. This paper investigates the effects of data resolution and uncertainty modeling on the HC calculation. To do so, a mathematical model of the HC problem is used in a Monte Carlo-based framework. Our analysis is carried out on an agricultural distribution network in Australia. It is shown that decreasing the resolution of historical data shifts the probability distribution function of the HC towards right implying an increase in the estimated HC. Further, it is illustrated that assuming a fixed capacity for DGs instead of proper modeling of the uncertainty associated with their size results in underestimation of the HC in the network.

The increasing penetration of non-synchronous renewable energy sources (NS-RES) has led to a decrease in power systems inertia which introduces major challenges to frequency stability. This paper investigates impacts of inertia location and network topology on frequency stability of power systems by the means of time domain simulations. We assess the contribution of fast frequency response (FFR) services on frequency performance of the system by considering the impact of FFR controller activation time delay. Furthermore, we derive analytical expressions to approximate rotor frequency and rate of change of frequency (RoCoF) which show that the impacts of reduced inertia can be studied by avoiding computationally extensive simulations. The results show that the FFR services provided by the NS-RES are attractive options in low inertia power systems.

Extremophiles, the microorganisms thriving in extreme environments, provide valuable resources for practicing novel biotechnological processes. Pakistan homes a wide spectrum of extreme environments which harbor various biotechnologically significant microorganisms. This review gauges the structural and functional bacterial diversity of several extreme environments, emphasizing their potentials as a source of extremozymes, and in bioleaching, bioremediation, and bioenergy production at regional level. Further, this review highlights a panoramic account of the local natural conservatories of extremophiles. The inadequacies of current fragmental research are discussed with suggestions to quantitatively define the structural and functional diversity of unexplored extreme localities.

This paper investigates the impact of high penetration of non-synchronous generation (NSG) and different penetration levels of price-responsive users equipped with rooftop photovoltaics-battery storage (PBS) (sometimes times referred to as prosumers) on the frequency stability of the Australian future grid. To do this, we employed a generic demand model proposed by the authors that captures the interaction between prosumers and an independent system operator (ISO) to provide the initial conditions for frequency stability assessment. In this approach, the ISO aims at minimising the total electricity costs, while prosumers' aggregation aims at maximising their self-consumption. To capture the inter-seasonal variation of renewable resources, we perform time-series simulation for a whole year. The results show the connection between NSG and frequency response of the system and how the system frequency response is affected with high penetration of NSG. Further, low PBS capacity of prosumers can worsen the frequency response of the system, whereas a higher PBS capacity of prosumers can improve the frequency response of the system due to a flatter net demand profile compared to the low PBS capacity.

The increasing penetration of non-synchronous renewable energy sources (NS-RES) alters the dynamic characteristic, and consequently, the frequency behaviour of a power system. To accurately identify these changing trends and address them in a systematic way, it is necessary to assess a large number of scenarios. Given this, we propose a frequency stability assessment framework based on a time-series approach that facilitates the analysis of a large number of future power system scenarios. We use this framework to assess the frequency stability of the Australian future power system by considering a large number of future scenarios and sensitivity of different parameters. By doing this, we identify a maximum non-synchronous instantaneous penetration range from the frequency stability point of view. Further, to reduce the detrimental impacts of high NS-RES penetration on system frequency stability, a dynamic inertia constraint is derived and incorporated in the market dispatch model. The results show that such a constraint guarantees frequency stability of the system for all credible contingencies. Also, we assess and quantify the contribution of synchronous condensers, synthetic inertia of wind farms and a governor-like response from de-loaded wind farms on system frequency stability. The results show that the last option is the most effective one., Comment: This paper is uploaded here just for reference. It is not published yet

Uncertainties associated with the loads and the output power of distributed generations create challenges in quantifying the integration limits of distributed generations in distribution networks, i.e., hosting capacity. To address this, we propose a distributionally robust optimization-based method to determine the hosting capacity considering the voltage rise, thermal capacity of the feeders and short circuit level constraints. In the proposed method, the uncertain variables are modeled as stochastic variables following ambiguous distributions defined based on the historical data. The distributionally robust optimization model guarantees that the probability of the constraint violation does not exceed a given risk level, which can control robustness of the solution. To solve the distributionally robust optimization model of the hosting capacity, we reformulated it as a joint chance constrained problem, which is solved using the sample average approximation technique. To demonstrate the efficacy of the proposed method, a modified IEEE 33-bus distribution system is used as the test-bed. Simulation results demonstrate how the sample size of historical data affects the hosting capacity. Furthermore, using the proposed method, the impact of electric vehicles aggregated demand and charging stations are investigated on the hosting capacity of different distributed generation technologies.

The reduced amount of rotational kinetic energy in power systems has significant detrimental impacts on system frequency behaviour. To ensure system security, this issue must be addressed in a systematic way. Given this, we consider three different metrics, namely i) minimum power penetration from synchronous generators, ii) minimum rated power of synchronous generators, and iii) minimum synchronous kinetic energy, as frequency control constraints in the market dispatch model, and assess frequency behaviour of the system for these metrics. The results show that each metric has a different impact on market dispatch, and, accordingly, on the system frequency behaviour. It is shown that with high penetration of converter-based generation, we need to consider a minimum kinetic energy requirement as a frequency control security constraint in the market dispatch model to guarantee the frequency stability of power systems.

The increasing integration of wind generation is accompanied with a growing concern about secure and reliable power system operation. Due to the intermittent nature of wind, the base-load units need to cycle significantly more than they were designed for, resulting in reduced life cycle and increased costs. Therefore, it is becoming necessary for wind turbines to take part in frequency control, and reduce the need for additional ancillary services provided by conventional generators. In this paper, we propose an optimised operation strategy for the wind farms. In this strategy, we maximise the kinetic energy of wind turbines by an optimal combination of the rotor speed and the pitch angle. We exploit the wake interaction in a wind farm, and de-load some of the up-wind turbines. We show that the kinetic energy accumulated in the rotating masses of the WTs can be increased compared to the base case without compromising efficiency of the wind farm. In a specific system, we show that by implementing this strategy, and injecting the stored kinetic energy of the WTs' rotors into the system during a frequency dip, we can delay the system frequency nadir up to 30 s., Comment: Presented in the 13th Wind Integration Workshop Berlin, Nov 11 - 13 2014

This paper proposes an optimal control strategy for participation of wind farms (WFs) in primary frequency control. In this strategy, we exploit wake interaction in a WF to maximise the total kinetic energy (KE) of the wind turbines' (WTs') rotating masses in the WF, and optimally deploy this KE after a frequency event to reduce the frequency nadir, by controlling the rate of change of the rotor speed. The amount of the KE injected into the system by the controller is proportional to the rate of change of frequency (RoCoF) and the frequency deviation after the contingency. By implementing this strategy in a test system with high penetration of wind energy, the stored KE of the WTs in the WF is gradually injected into the system during a frequency excursion. The results show that not only the system frequency nadir is reduced, but also the system frequency is kept relatively uniform for up to 50s.

Fifty patients with thoracolumbar fractures were treated operatively between July 2000 and December 2001. The average age of the patients was 33.6 years (range: 20–50 years), 36 were males and 14 were females and the follow-up averaged 59 months (range: 49–68 months). A fall from a height, usually a tree, was the most common cause of injury. Twenty six patients had unstable burst fractures and 13 had translational injury. There were 15 patients with complete neurological deficit, 17 had partial neurological lesions, while 18 had no neurological deficit. All patients were treated by posterior short segment fixation (Steffee VSP). The average pre-operative kyphotic angle was 21.48°, which improved to 12.86° in the immediate post-operative period. The loss of kyphosis averaged 3.46° (0–26°) at the final follow-up. The average pre-operative anterior vertebral body height was 44.7% (range: 36–90%), which improved to 72.0% (range: 55–97%) in the immediate post-operative period. The loss of body height averaged 3.0% (range: 1–15%) at the final follow-up. No neurological deterioration was seen, and in 24 cases a one grade or better improvement was observed. The mean pain score was 1.6, and the mean functional score was 2.8. We found that the application of posterior instrumentation resulted in a reasonable correction of the deformity with a significant reduction in recumbency-associated complications; there were, however, significant other complications.

The parotid gland with two ducts is a rare anomaly and very few cases have been reported in the literature. The Present study was conducted in the postgraduate Department of Anatomy at Government Medical College Srinagar to study the variations in the pattern and number of ducts of parotid gland during routine dissection for academic purposes between 2001 -20014. Both parotid glands of 36 Indian cadavers were dissected out for routine anatomic teaching and simultaneously recording observations. In this study we also included 10 formalin preserved specimens of parotid gland. It was observed that in one of the cadavers two ducts emerged from the anterior border of right parotid gland. These ducts D1 (superior) and D2 (inferior) joined after crossing the anterior border of the masseter muscle and formed a common duct (D3) in the form of letter ‘Y’, which pierced the buccal pad of fat, buccopharngeal fascia, buccinator muscle and mucous membrane before opening inside the vestibule of mouth. This anomalous duct pattern though rare is of great academic and clinical significance in Otorhinology, Maxillofacial and Plastic surgery, where it may explain the occurrence of post traumatic/iatrogenic parotid fistulas and need for preoperative sialography during surgical procedures of this region.

Dear Editor, We thank the correspondent for his comments and for providing us a chance to clarify a few important points. Our main objective was to review the outcome of the treatment of unstable thoracolumbar spinal fractures by short-segment spinal fixation. Instrumentation failure is a known complication of this type of treatment. We mentioned this as an adverse outcome in our series [1]. We concur with the observation that posterior instrumentation is weaker in compression and is liable to fatigue and fail in the presence of a coexisting weak anterior column. We, however, believe that instrumentation failure is multifactorial and factors other than implant design and fracture characteristic contribute to it [2]. Although some authors have claimed better results using fixation two levels above and below the injured segment in severe vertebral comminution [3], we do not have any experience with this technique. Our paper is primarily meant to assess and report the results of short-segment fixation only. We however believe that anterior column reconstruction would be a better choice in such cases to the extent of obviating the need for transpedicular grafting. In essence we have tried to report the results of short-segment posterior instrumentation in totality and reflect the requirement of a more comprehensive classification, which would narrow down the indications of this instrumentation, thereby ensuring better results. We are currently working on developing a classification (unpublished data) by combining the system of MacAfee [4] and McCormack [5] in an attempt to pre-operatively segregate the patients for treatment by anterior or posterior instrumentation.

Teucrium royleanum was tested by four variant assays using lettuce seeds, showing excellent inhibition. The plants leaf leachates were assayed by Sandwich and Homogenated Sandwich Methods while Dish Pack Method was used for the evaluation of essential oils. The above stated methods confirm the presence of allelochemicals in T. royleanum and were further evaluated in bioassay guided way by total activity approach. The methanol subsequent fractions; hexane, chloroform, ethylacetate, butanol and water fractions were assayed by the Total Activity Method. The essential oils, hexane and chloroform fractions played a decisive role in our findings. The results from this study suggested that the secondary metabolites from T. royleanum can be potential candidates for the phytotoxicity (Allelopathy) and can be utilized on commercial scale for the development of new herbicides or weedicides.