bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvisation on Standard Limit of the Critical Clearing Time Specified for the Protection Relays Using one Machine Infinite Bus Equivalent
Authors: Salim Nur Ashida , Othman Muhammad Murtadha , Musirin Ismail , Serwan Mohd Salleh
Published: August 2015

This paper presents a computationally accurate technique used to determine the critical clearing time using the one machine infinite bus equivalent system based on the equal area criterion. The critical clearing time is the maximum time interval by which the fault must be cleared in order to preserve the system stability. The computation of critical clearing time involves an intrinsic mathematical formulation derived from the pre-fault, during fault and post-fault conditions. The value of critical clearing time becomes significantly less when transient instability is induced by a three phase fault occurred at the bus bar closest to the substation connected with a sensitive generator. By setting the protection relay with the obtained value of critical clearing time, it is adequate to sustain the transient stability even though fault happened at the other locations. During the occurrence of fault, a circuit breaker which is operating earlier than the smallest critical clearing time will not agitate to a transient instability. The IEEE Reliability Test System 1979 (RTS-79) is used to verify the robustness of the methodology in a determining the critical clearing time.
A Novel of Fault Localization Method to Determine Fault Distance for Single Line to Ground Fault in the Distribution Network
Authors: Awalin L.J. , Mokhlis Hazlie , Bakar A.H.A. , Illias Hazlee Azil
Published: August 2015

In this paper, a novel fault location algorithm in distribution networks based on combination of impedance based method is presented. The voltage sag and current swell from the measurement node are used as input data to estimate the fault distance. To improve the accuracy of the proposed method, the voltage sag and current swell in the un-faulted phase also considered. Test results using a large scale distribution network from Malaysia confirms the accuracy of the proposed method. A comparison is made with the existing method which shows that the proposed method gives more accurate fault distance.
Adaptive Distance Protection to Prevent False Relay Tripping during Power Swing
Authors: Mohamad Nor Zulaily , Abidin Ahmad Farid , Musirin Ismail
Published: August 2015

The existing distance relay is accommodated with starting function to detect short-circuits in power system. However, this function proves vulnerable to distance relay operation as it could falsely send a tripping signal during power swing. Hence, it is important to introduce an adaptive concept to the distance protection to prevent such false tripping. This paper presents a simple and effective adaptive protection algorithm for power swing prevention based on Under Impedance Fault Detector (UIFD) characteristics, in which capable to identify the power swing condition and adjusting the relay setting accordingly to avoid system mal-operation.
Surface Discharge Characteristics on HDPE, LDPE and PP
Authors: Dabbak Sameh , Illias Hazlee , Bee Chin Ang , Tunio Mohsin Ali
Published: August 2015

The degradation of polymer insulation is affected by many factors. One of the main factors is surface discharge. In this work, the characteristics of surface discharge on different types of polymer insulation material under different types of electrode shapes were studied. The insulation materials used were high density polyethylene (HDPE), low density polyethylene (LDPE) and polypropylene (PP). Different types of electrode shape used were sharp, flat and sphere electrodes. From the experiments that have been performed, surface discharge characteristics were found to be influenced by the type of insulation material and the electrode shape. Hence, a better understanding on the characteristics of surface discharges may be attained.
Constrained Reactive Power Control (CRPC) Based Multi-Objective Optimization under Multi-Contingencies (N-m)
Authors: Abdullah Nor Rul Hasma , Morgan Mahaletchumi A.P. , Musirin Ismail
Published: August 2015

Optimal Reactive Power Dispatch (ORPD) is needed for reduces the power system losses and improves voltage profile, power system security and overall power system operation. In this paper, the ORPD problem solved using Constrained Reactive Power Control (CRPC) based Multi-Objective Evolutionary Programming (MOEP) optimization technique considering multi-contingencies (N-m). The proposed technique determines the optimum reactive power to be dispatched by the generators in order to improve voltage stability condition of a system. A computer program was written in MATLAB and the proposed technique was tested on the IEEE 30-bus RTS. Hence, the result was compared with Multi-Objective Artificial Immune System (MOAIS) to highlight it merits.
A Design of an Automatic Single Phase Power Factor Controller by Using Arduino Uno Rev-3
Authors: Ishak Nurul Huda , Zainodin Muhammad Naim , Salim Nur Ashida , Twon Tawi Faizal Muhamad , Mohd Saod Aini Hafiza
Published: August 2015

This paper presents a computationally accurate technique to design an automatic single phase power factor controller by using microcontroller. The hardware implementation was developed by using Arduino Uno Rev-3 main board which uses the ATmega328 as the microcontroller. The power factor value from the load was measured by using voltage and current transformers, zero crossing detectors, and ATmega328 microcontroller. Zero crossing detectors produced current and voltage signals which will be measured and calculated for the time difference between both signals by ATmega328 microcontroller using appropriate algorithms in order to obtain value of power factor. The ATmega328 is programmed to automatically switch on and off capacitor function in order to control the signal pulse send to relay to connect and disconnect capacitor parallel with the load when energized and de energized if the calculated power factor value is either below 0.9 or above 0.9, respectively. Simulation of the power factor controller model was performed by using Proteus software. Arduino IDE software was used as the compiler for the Arduino Uno. The main objective is to study and develop the technology of automatic single phase power factor controller using Arduino Uno Rev-3 by controlling the power factor of the inductive load near to unity power factor. The results of the power factor value were displayed on the LCD and the power factor is corrected if it falls below 0.9 in order to prevent penalty by the power supplier. The effectiveness of the proposed technique could assist the monitoring unit in order to maintain the power factor at the value set by the utility.
Reactive Power Compensation in Oman 400kV Transmission System
Authors: Abdalla Omar H. , Al-Riyami Hisham , Al-Busaidi Adil , Al-Nadabi Ahmed , Al-Rawahi Zahra , Al-Siyabi Musabah , Fronius Rainer , Miksa Predrag
Published: August 2015

The objective of this paper is to present the challenges, methodological approach and possible solutions for the overvoltage issue during the winter light load period in the Main Interconnected Transmission System (MITS) of Oman after introducing the new 400kV system. Load flow studies of the planned MITS in 2016, including representation of other local and GCC interconnection grids, have shown overvoltage issues at the 400kV substations in Oman during winter off-peak demand. These voltage issues can even lead to difficulties in synchronizing the 400kV circuits. Simulation results are presented to define the size and location of a reactive power compensator which can resolve such overvoltage issues. Many options of the reactive power compensation, including fixed and variable means, have been studied and the best option (fixed shunt reactors) is selected.
An Application of Grey Wolf Optimizer for Commodity Price Forecasting
Authors: Mustaffa Zuriani , Sulaiman Mohd Herwan , Yusof Yuhanis
Published: August 2015

Over the recent decades, there are many nature inspired optimization algorithms have been introduced. In this study, a newly algorithm namely Grey Wolf Optimizer (GWO) is employed for gasoline price forecasting. The performance of GWO is compared against the results produced by Artificial Bee Colony (ABC) algorithm and Differential Evolution (DE) algorithm. Measured based on Mean Absolute Percentage Error (MAPE) and prediction accuracy, the GWO is proven to produce significantly better results as compared to the identified algorithms.
Artificial Neural Network Application in Optimal Coordination of Directional Overcurrent Protective Relays in Electrical Mesh Distribution Network
Authors: Emmanuel Osaji , Lutfi Othman Mohammad , Hizam Hashim , Murtadha Othman Muhammad
Published: August 2015

Directional Overcurrent relays (DOCR) applications in meshed distribution networks (MDN), eliminate short circuit fault current due to the topographical nature of the system. Effective and reliable coordination’s between primary and secondary relay pairs ensures effective coordination achievement. Otherwise, the risk of safety of lives and installations may be compromised alongside with system instability. This paper proposes an Artificial Neural Network (ANN) approach of optimizing the system operation response time of all DOCR within the network to address miscoordination problem due to wrong response time among adjacent DOCRs to the same fault. A modelled series of DOCRs in a simulated IEEE 8-bus test system in DigSilent Power Factory with extracted data from three phase short circuit fault analysis adapted in training a custom ANN. Hence, an improved optimized time is produced from the network output to eliminate miscoordination among the DOCRs.
Solving Economic Dispatch Problems with Practical Constraints Utilizing Grey Wolf Optimizer
Authors: Wong Lo Ing , Sulaiman Mohd Herwan , Mohamed Mohd Rusllim
Published: August 2015

This paper presents the application of a new meta-heuristic called Grey Wolf Optimizer (GWO) which inspired by grey wolves (Canis lupus) for solving economic dispatch (ED) problems. The GWO algorithm mimics the leadership hierarchy and hunting mechanism of grey wolves in nature. Four types of grey wolves such as alpha, beta, delta, and omega are employed for simulating the leadership hierarchy. In addition, the three main steps of hunting: searching for prey, encircling prey and attacking prey are implemented. In this paper, GWO was demonstrated and tested on two well-known test systems with practical constraints. A comparison of simulation results is carried out with those published in the recent literatures. The results show that the GWO algorithm is able to provide very competitive results for nonlinear characteristics of the generators such as ramp rate limits, prohibited zone and non-smooth cost functions compared to the other well-known meta-heuristics techniques.
Power Plant Performance Based on Power-Efficiency Curve of Hydroelectric Power Plant
Authors: Zulkifli Anis Shazwani , Muhamad Razali Noor Miza , Marsadek Marayati , Yahya Zainuddin , Juhana Tengku Hashim Tengku
Published: August 2015

—Hydropower energy is widely used throughout the world. It is the only renewable energy that is presently commercially practical on the large scale. In order to maintain the hydropower plant in good condition, the performance of the power plant needs to be monitored constantly. Efficiency curve helps in studying the performance of the turbine under various conditions and this is the best way to look for the performance of the power plant. Therefore, this paper presents the relationship between load (MW) and efficiency of each turbine and generator unit. This project uses Microsoft Excel 2010 software to produce a graph from the exact data produced from the database. This paper’s objective is to compare the theoretical performance curve and the calculated performance curve and also to discuss the hydroelectric power plant performance.
Optimal Placement and Sizing of Renewable Distributed Generation via Gravitational Search Algorithm
Authors: Daud Sa'adah , Abdul Kadir Aida Fazliana , Gan Chin Kim , Abdullah Abdul Rahim , Sulaima Mohamad Fani , Shamsudin N.H.
Published: August 2015

The installation of distributed generation (DG) gives advantages to the environment such as, it contribute in the reduction of non-peak operating cost, diversification of energy resources, lower losses thus improving overall organization. These advantages might be rescinded if no proper location and sizing of DGs are considered before the DG’s installation. This paper offers an optimal location and sizing of multiple DGs using heuristic method called gravitational search algorithm (GSA). The suggested algorithm is tested on 13-bus radial distribution system. This method is being compared with particle swarm optimization (PSO) in terms of system power loss, voltage deviation and total voltage harmonic distortion (THDv). GSA shows the ability to locate and sized DG optimally with a better performance and more reliable than PSO.
Control Strategies for a Standalone Hybrid Renewable Energy System
Authors: Arul P.G. , Ramachandaramurthy V.K.
Published: August 2015

This paper presents a standalone hybrid renewable energy system (SHRES) to supply alternating current (AC) loads. The interfacing configuration of SHRES sources to the AC bus is discussed. The control strategies based on voltage and frequency (Vf) with droop concept for the stable source and active and reactive (PQ) power control concept for the energy sources are proposed for the SHRES’s stability, power quality and load sharing. The SHRES and the control strategies have been modeled in PSCAD/EMTDC software. Simulation results show the proposed control strategy is shown to be able to regulate the voltage and frequency at the common AC bus.
Determination of Optimal Location, Sizing and Power Factor of Grid-Connected Solar PV Plant
Authors: Huy Phung Dang , Ramachandaramurthy V.K.
Published: August 2015

The increasing number of grid-connected solar PV plants today has brought great benefits to the power system. However, it has also created several technical issues that need to be addressed by planning engineers. Due to this reason, the optimization for interconnection of solar PV plants has attracted their attentions, in order to operate these plants safely and economically. In this paper, three key parameters which are the location, size and operating power factor of the solar PV plant are optimized. The proposed method considers the technical constraints of the network such as voltage limits, together with the intermittency of PV generation and system loads. Two case studies are simulated on a typical 11kV distribution system with 54 buses. Results show a reduction in system energy losses for the optimized values, without violating any power system requirements.
Two Stage Optimal Capacitors Placement and Sizing Using Differential Evolution Particle Swarm Optimization
Authors: Abdul Razak Muhd Azri , Othman Muhammad Murtadha , Yahya Mohd Ainor , Zakaria Zilaila , Musirin Ismail , Kari Mat Nasir , Osman Mohd Fazli , Abu Hassan Mohd Zaini , Mohd Dzin Siti Habsah , Azrae Baihaki , Wan Ismail Wan Shazli , Salleh Mohd Hisham , Jafar Shaharani
Published: August 2015

Installing capacitors in a large unbalanced electrical distribution system will indeed improves the performance of the system in terms of its voltage profile and real power loss stability. However, determining the suitable locations for capacitors installation with an appropriate sizing in an unbalanced electrical distribution system involves an intricate process. This impediment can be resolved by implementing an optimal capacitors placement and sizing. The proposed technique is a highly nonlinear optimization problem which requires discrete and multi-dimensional control variables of capacitor locations and sizes. This paper proposed a new artificial intelligence approach used to reduce the total line real power loss and total real power consumption while maintaining the voltage profile along the feeders. It was done by integrating the circuitry schematic diagram of an unbalanced electrical distribution system modeled in SIMULINK® software with the computational programming based differential evolution particle swarm optimization (DEPSO) for optimal capacitors placement and sizing developed under the MATLAB® software. In this study, pre-selection of the capacitor locations can be considered as the first stage of the proposed concept and it is commenced prior to the optimization process performed by the DEPSO algorithm considered as the second stage of the proposed concept. A modified IEEE 13-bus unbalanced radial distribution system is used verify effectiveness of the proposed technique in solving the problem. The results will be discussed notably through comparative studies on the objective function of total cost and performance of the DEPSO technique.
An Iterative Algorithm for Sizing Stand-Alone Photovoltaic System
Authors: Abdul Aziz Nur Izzati , Sulaiman Shahril Irwan , Shaari Sulaiman , Musirin Ismail
Published: August 2015

This paper presents a methodology for sizing Stand-Alone Photovoltaic (SAPV) system. An iterative-based sizing algorithm, known as ISA, was developed for determining the optimal PV module, battery, charge controller and inverter such that the expected Performance Ratio (PR) of the system could be maximized. The ISA basically evaluates all possible combinations of SAPV system components derived from the respective database of each component. Two sizing scenarios were evaluated based on the types of charge controller that has been used, i.e. the standard charge controller and maximum power point tracker (MPPT)-based charge controller. Results showed that the optimal sizing solution was discovered within 14 to 19 hours based on an evaluation of 46,080 possible combinations of components.
Optimal Control of Solar Energy Resources in Loading Margin Enhancement for Peninsular Malaysia Network Using Artificial Neural Network (ANN) Model
Authors: bin Salim Norhafiz , Tsuji Takao , Oyama Tsutomu , Uchida Kenko
Published: August 2015

Renewable energy invariably foreseen to be fully spurs by 2030-2050 and Malaysia has been seriously intensifies their capabilities on producing solar energy for generating amount of power to be injected into the national grid. The aim of this paper is to investigate the provision of photovoltaic generators quantitatively with respect to future load generation while considering the Loading Margin (LM) capability. Renewable energy resources are known with its ambiguity and commonly for rural electrifications each houses or buildings are installed with battery storage system which allows unused power during daytime to be stored and will be utilized at night. This kind of system would not experience big impact in conjunction of intermittent level of insolation due to its small requirement at receiving end. Conversely, in big cities located in the west region of Malaysia it becomes a big issue to cope with variations of load demand. In an explicit form of voltage deficiency caused by irregular operation on the grid, a fragile electrical nodes most likely vulnerable and PV generators are inevitably have to stay connected to the point of common coupling supporting grid’s voltage. Eventually at this stage, Grid System Operator (GSO) needs to have brisk respond to these online scenarios but in practice it could not be done at ease. Thus, an intelligent model of ANN which incorporated tremendous set of local data is developed in this paper to regulate loading margin (LM) at critical node by taking into account possible wheather condition at any given time and loading increments. This method employed a kind of supervised training and successfully yields smart predictive technique of LM in any certain correspond inputs. By having this, GSO can barely make the arrangement of reactive power injection throughout the network with the central coordination control among PV generators. Simulation results show the effectiveness of the proposed method and have been discussed thoroughly.
Multi-State Modeling Incorporated with Analytical Approach for Reliability Evaluation
Authors: Zulkifli Nadiah Amalina , Muhamad Razali Noor Miza , Juhana Tengku Hashim Tengku , K. Ramasamy Agileswari , Marsadek Marayati
Published: August 2015

Renewable energy sources such as wind, solar, biomass, wave and tidal energy have become favourable alternatives to replace conventional generators due to excessive emission of harmful gaseous and depletion of natural resources. From all of the energy sources, solar photovoltaic is chosen in this paper because it is considered as an inexhaustible energy in Malaysia. Yet it is still in infancy stage due to high cost of implementation. This paper adopts a multi-state method for photovoltaic output power modelling which is incorporated with analytical technique to evaluate the capacity outage probability of a power system consisting both conventional and renewable generators. Consequently, this is to evaluate the system reliability index which is the Loss of Load Probability (LOLP). The results show that the presence of solar photovoltaic enhances the overall LOLP of the system.
Battery Parameters Identification Analysis Using Periodogram
Authors: Kasim Rizanaliah , Abdullah Abdul Rahim , Selamat Nur Asmiza , Baharom Mohamad Faizal , Ahmad N.H.T.H.
Published: August 2015

Batteries are essential components of most electrical devices and one of the most important parameters in batteries is storage capacity. It represents the maximum amount of energy that can be extracted from the battery under certain specified condition. This paper presents the analysis of charging and discharging battery signal using periodogram. The periodogram converts waveform data from the time domain into the frequency domain and represents the distribution of the signal power over frequency. This analysis focuses on four types of batteries which are lead-acid (LA), lithium-ion (Li-ion), nickel-cadmium (Ni-Cd) and nickel-metal-hydride (Ni-MH). This paper used battery model from MATLAB/SIMULINK software and the nominal voltage of each battery is 6 and 12V while the capacity is 10 and 20Ah, respectively. The analysis is done and the result shows that varying capacity produce different power at a frequency and voltage at DC component.
Lead Acid Battery Analysis Using Spectogram
Authors: Kasim Rizanaliah , Abdullah Abdul Rahim , Selamat Nur Asmiza , Abidullah N.A. , Zawawi Tengku Nor Shuhadah Tengku
Published: August 2015

Renewable energy is an alternative option that can be substituted for future energy demand. Many type of battery are used in commerce to propel portable power and this makes the task of selecting the right battery type is crucial. This paper presents the analysis of voltage charging and discharging for lead acid battery using time-frequency distribution (TFD) which is spectrogram. Spectogram technique is used to represent the signals in the time-frequency representation (TFR). The parameter of a signal such as instantaneous root mean square (RMS) voltage, direct current voltage (VDC) and alternating current voltage (VAC) are estimated from the TFR to identify the signal characteristics. This analysis, focus on lead-acid battery with nominal battery voltage of 6 and 12V and storage capacity from 5 until 50Ah. The battery is a model using MATLAB/SIMULINK and the results show that spectrogram technique is capable to identify and determine the signal characteristic of Lead Acid battery.
Optimal Quick Charging Station Placement for Electric Vehicles
Authors: Islam Md. Mainul , Shareef Hussein , Mohamed Azah
Published: August 2015

Environmental concerns, dependency on imported petroleum and lower cost alternative to gasoline always motivated policymakers worldwide to introduce electric vehicles in road transport system as a solution of those problems. The key issue in this system is recharging the electric vehicle batteries before they are exhausted. Thus, the charging station should be carefully located to make sure the vehicle users can access the charging station within its driving range. This paper therefore proposes a multi-objective optimization method for optimal placement of quick charging station. It intends to minimize the integrated cost of grid energy loss and travelling of vehicle to quick charging station. Due to contrary objectives, weighted sum method is assigned to generate reference Pareto optimal front and optimized the overture by genetic algorithm. The results show that the proposed method can find the optimal solution of quick charging station placement that can benefit electric vehicle users and power grid.
Research and Development of Automatic Control System for Electric Arc Furnace Electrode Positioning
Authors: Nikolaev Alexander , Povelitsa Evgeniy , Kornilov Gennady , Anufriev Anton
Published: August 2015

The article is concerned with the advanced automatic control system of electrode positioning at electric arc steel making furnaces and ladle furnaces. Analysis of structure of modern electrode positioning control systems’ nonlinear controllers for electric arc furnaces and ladle furnaces is considered. Disadvantages of these systems were analyzed. A control system with a conventional structure from well-established foreign suppliers was compared with the advanced automatic control system of electrode positioning.
PC Based Energy Efficient Wireless Transceiver Module with ZigBee
Authors: Bilal Sarwar Muhammad , Nallagownden Perumal , Baharudin Zuhairi , Sundaram Muthuvalu Mohana
Published: August 2015

The aim of this research is to develop a low power, low cost and energy efficient transceiver model which is integrated with programmable microcontroller and ZigBee transponder. A combination of programmable microcontroller with ZigBee transponder is used to control the transceiver module with computer commands. It has b een simulated for transmitting and receiving the communication signals from any movable device with more efficiently and use low power consumption. ZigBee Transponder is preferable as compared to radio frequency identification (RFID) due to IEEE 802.15.4 standard that promises stable data transmission with low power consumption device and having higher network flexibility. PIC 16F877A programmable microcontroller with coding in Mikro C software is simulated and used with computer control instructions. Series of experiments has been conducted to ensure the stability and low power consumption of this model.
Experimental Depth Positioning Control for a Spherical Underwater Robot Vehicle (URV)
Authors: Eltigani Ibrahim Abdalla , Noh Karsiti Mohd , Elamvazuthi Irraivan
Published: August 2015

Recently, position control of URVs has been a challenge due to the buoyancy forces, and high current load of ocean. In this paper, variable ballast tank (VBT) of a spherical URV is developed as vertical motion actuator, and the problem of internal dynamic forces which caused by empty space inside the VBT has been discussed. In order to test the stability of the proposed system, the experimental model of URV has been tested in 1-5 meter underwater depth.
The Improved of BFOA for Ensuring the Sustainable Economic Dispatch
Authors: Hassan Elia Erwani , Rahman Titik Khawa Abdul , Zakaria Zuhaina , Bahaman Nazrulazhar
Published: August 2015

This paper introduced a new heuristic method the Improved to Bacterial Foraging Optimization Algorithm or IBFO to provide minimize objective functions in Secured Environmental Economic Dispatch (SEED) problems. An optimization problem may involve the highly non linear, non convex and non differentiable tends the solutions observed from a multiple local minima. The limitation faced by conventional methods are being trapped at any this local minima and prevent to reach the global minima. For that reason, this approach IBFO is tested under IEEE 118 bus system to obtain the minimum total cost function with less emission involved. Additionally, the proposed optimization approach is compared to original Bacterial Foraging Optimization Algorithm (BFO). As a result, all findings supported the novel IBFO as the competent and reliable technique.
The northward distribution of ants (Hymenoptera: Formicidae) 40 years later: revisiting Robert E. Gregg’s 1969 Subarctic collection sites in Churchill, Manitoba, Canada
Authors: Smith M. Alex , Boyd Amanda , Bringloe Trevor , Britton-Foster Christopher , Cahill Hayley , Desnoyers Kelsey , Duitshaever Natalie , Gibson Daniel , James Stephen , Jeong Yurak , Kelly Darren , Levene Elli , Lyttle Hilary , Masse Talia , Pare Kate , Paris Kelsie , Russell Cassandra , Scott Eric , Silva Deborah , Sparkes Megan , Valkova Kami , Adamowicz Sarah J.
Published: August 2015

In 1969, Robert E. Gregg collected five species of ants (Hymenoptera: Formicidae) in three Subarctic localities near the town of Churchill, Manitoba, Canada, which he documented in a 1972 publication in The Canadian Entomologist. To determine whether there have been any additions to the local fauna – as might be predicted to occur in response to a warming climate and increased traffic to the Port of Churchill in the intervening 40 years – we re-collected ants from the same localities in 2012. We identified the ants we collected from Gregg’s sampling sites using both traditional morphological preparations and DNA barcoding. In addition, we examined specimens from Gregg’s initial collection that are accessioned at the Field Museum of Natural History (Chicago, Illinois, United States of America). Using this integrative approach we report seven species present at the same sites Gregg sampled 40 years earlier. We conclude that the apparent increase is likely not due to any arrivals from more southerly distributed ants, but to the increased resolution provided by DNA barcodes to resident species complexes with a complicated history. We provide a brief synopsis of these results and their taxonomic context.
Religie en globale bio-etiek: Religieuse globale bio-etiek as voorloper tot ’n universele bio-etiek
Authors: Rheeder Riaan
Published: August 2015

Religion and global bioethics: Religious global bioethics as a precursor to a universal bioethics. From a general public perspective, this article presumes that there is such a thing as a universal ethics; however this assumption does not decrease the challenges with regard to a ‘global ethics’ and ‘bioethics’. The article discusses the views on global religious bioethics that were formulated in 1999. The article further considers these formulations as the forerunner of UNESCO’s perspective on universal bioethics accepted in 2005. The article aims to argue that a global value system will enhance hope of peace and justice in today’s global world. It argues that the absence of shared ethics will reinforce conflict between civilisations and worsen injustice.
D(i)e verhouding prediking, mus(z)iek en liturgie
Authors: Wepener Cas , Klomp Mirella
Published: August 2015

The relationship between preaching, music and liturgy. In the Reformed liturgy in South Africa the sermon has traditionally been reserved a special place, taking precedence over the liturgy and music. In this article an argument is put forward for a better balance between preaching, liturgy and music in the Reformed liturgy in churches in South Africa. In order to do so, the South African Reformed liturgical context is briefly sketched and thereafter a theological and liturgical-historical argument is presented. Existing approaches with regard to the relationship between liturgy, music and preaching by some established scholars are discussed before the implications of the argument are examined in conclusion.
Treating Elderly Patients with Hormone Receptor–Positive Advanced Breast Cancer
Authors: Riseberg David
Published: August 2015

As the overall population ages, the proportion of elderly patients (aged ≥65 years) with breast cancer also increases. Studies have shown that elderly patients with hormone receptor–positive breast cancer can derive as much benefit from treatment as do younger patients, yet they remain underrepresented in clinical trials and are often undertreated in clinical practice. Treatment decisions for older patients should not be based solely on chronologic age; a patient's physiologic functioning and comorbidities must also be taken into consideration. For recurrent or metastatic disease, systemic treatment with endocrine therapies or chemotherapy may prolong a patient's life and alleviate troublesome symptoms. Resistance to therapy remains a problem in the advanced breast cancer setting, with most patients eventually becoming resistant to additional treatment. New combination regimens that target multiple pathways, such as everolimus plus exemestane, have shown efficacy in elderly patients previously resistant to endocrine therapies, and future research may need to focus on such combinations in order to improve outcomes in this patient group. A number of investigational agents are in clinical development, although few studies identify their effects in the elderly patient population. Optimizing effective yet tolerable therapeutic regimens for elderly patients could improve their outcomes while ensuring that the goals of improved survival and quality of life are considered.
Licuri oil supplements for lactating cows on pasture
Authors: Lima Luciano S. , Oliveira Ronaldo L. , Neto Américo F. Garcez , Bagaldo Adriana R. , Abreu Claudilene L. , Silva Thadeu M. , Carvalho Silvana T. , Bezerra Leilson R.
Published: August 2015

Lima, L. S., Oliveira, R. L., Garcez Neto, A. F., Bagaldo, A. R., Abreu, C. L., Silva, T. M., Carvalho, S. T. and Bezerra, L. R. 2015. Licuri oil supplements for lactating cows on pasture. Can. J. Anim. Sci. 95: 617–624. As licuri [Syagrus coronata (Martius) Beccari] oil can be a beneficial energy source in the diet of lactating cows managed on pasture, this study aimed to determine the most effective level of licuri oil in feed supplements. Sixteen Holstein×Zebu crossbreed lactating cows grazing on Tanzania (Panicum maximum) pasture grass were grouped into two 4×4 simultaneous Latin squares; there were four experimental periods of 21 d each, with 17 adaptation days and 4 d of data collection. The treatments were diets containing 0.0, 15.0, 30.0 or 45.0 g kg−1of licuri oil in concentrated dry matter. The intakes of dry matter, crude protein and non-fiber carbohydrate levels were not affected by the addition of licuri oil; however, the intake of neutral detergent fiber and total digestible nutrients decreased linearly. Neutral detergent fiber digestibility was reduced linearly with increasing levels of licuri oil in the concentrate. There were no changes in blood glucose levels, but blood urea nitrogen levels varied according to the time of the day when the blood was collected. Inclusion of licuri oil at 45.0 g kg−1in feed concentrates results in improved dry matter and ether extract digestibility.
Feeding subtherapeutic antimicrobials to low-risk cattle does not confer consistent performance benefits
Authors: Stanford K. , Gibb D. J. , Schwartzkopf-Genswein K. S. , Van Herk F. , McAllister T. A.
Published: August 2015

Stanford, K., Gibb, D. J., Schwartzkopf-Genswein, K. S., Van Herk, F. and McAllister, T. A. 2015. Feeding subtherapeutic antimicrobials to low-risk cattle does not confer consistent performance benefits. Can. J. Anim. Sci. 95: 589–597. Two-hundred and forty steers were obtained from the same ranch in each of 2 yr. Growth performance, health status and carcass characteristics from steers fed subtherapeutic antimicrobials were compared with those of control steers without antimicrobial metaphylaxis. Experimental groups included Control, not fed antimicrobials; CTCS-700, fed 350 mg head−1 d−1 chlortetracycline (CTC) and 350 mg head−1 d−1 sulfamethazine; CTC-11, fed 11 mg kg−1 CTC; TYL, fed 11 mg kg−1 tylosin phosphate; and CTC-350, fed 350 mg head−1 d−1 CTC. Steers were housed in pens of 10 steers and fed antimicrobials during both backgrounding and finishing periods. The incidence of bovine respiratory disease, pinkeye and bloat did not differ among experimental groups, although the incidence of foot rot was lower in Control steers (P<0.05) than in steers receiving TYL. In both years of the study, overall performance (backgrounding+finishing) was not improved by subtherapeutic antimicrobials. Similarly, carcass characteristics and the incidence and severity of liver abscesses were not improved compared with Control steers by feeding subtherapeutic antimicrobials. The results of the present study demonstrate that low-risk steers may be managed in small pens with equivalent growth performance, carcass characteristics and health status to steers fed subtherapeutic antimicrobials.
Feeding a brown midrib corn silage-based diet to growing beef steers improves growth performance and economic returns
Authors: Saunders C. S. , Yang S. Y. , Eun J.-S. , Feuz D. M. , ZoBell D. R.
Published: August 2015

Saunders, C. S., Yang, S. Y., Eun, J.-S., Feuz, D. M. and ZoBell, D. R. 2015. Feeding a brown midrib corn silage-based diet to growing beef steers improves growth performance and economic returns. Can. J. Anim. Sci. 95: 625–631. A feedlot experiment was performed to determine growth performance, ruminal fermentation characteristics, and economic returns for growing beef steers when fed a brown midrib corn silage-based total mixed ration (BMRT) compared with a conventional corn silage-based total mixed ration (CCST). Twenty-four Angus crossbred steers (initial body weight=258±23.2 kg) in individual pens were used in a completely randomized design (n=12). Intake of dry matter was not different between the treatments. Steers fed the BMRT tended to have greater average daily gain (1.54 vs. 1.42 kg d−1; P=0.09) and gain-to-feed ratio (0.165 vs. 0.146; P=0.07) compared with those fed the CCST. Feeding the BMRT increased total volatile fatty acid (VFA) concentration (P=0.01) compared with the CCST, while it decreased molar proportion of acetate (P<0.01), and increased propionate proportion (P=0.01), resulting in decreased acetate-to-propionate ratio compared with the CCST (P<0.01). Steers fed the BMRT increased feed margin (P=0.05) and net return (P=0.02) compared with those fed the CCST throughout the trial. Overall results of this study indicate that feeding the BMRT to growing beef steers enhanced ruminal fermentation and beneficially shifted VFA profiles, which contributed to improved growth and economic performance of steers.
Nondegeneracy in the obstacle problem with a degenerate force term
Authors: Yeressian Karen
Published: August 2015

In this paper we prove the optimal non degeneracy of the solution

u

of the obstacle problem

\triangle u=f\chi_{\{u>0\}}

in a bounded domain

D\subset\mathbb{R}^{n}

, where we only require

f

to have a nondegeneracy of the type

f(x)\geq\lambda\vert (x_1,\cdots,x_p)\vert^{\alpha}

for some

\lambda>0

,

1\leq p\leq n

(an integer) and

\alpha>0

. We prove optimal

(2+\alpha)

-th order non degeneracy. We also prove the optimal growth with the assumption

\vert f(x)\vert\leq\Lambda\vert (x_1,\cdots,x_p)\vert^{\alpha}

for some

\Lambda\geq 0

and the porosity of the free boundary.
Investigation of post-depositional processing of nitrate in East Antarctic snow: isotopic constraints on photolytic loss, re-oxidation, and source inputs
Authors: Shi G. , Buffen A. M. , Hastings M. G. , Li C. , Ma H. , Li Y. , Sun B. , An C. , Jiang S.
Published: August 2015

Abstract. Snowpits along a traverse from coastal East Antarctica to the summit of the ice sheet (Dome Argus) are used to investigate the post-depositional processing of nitrate (NO3−) in snow. Seven snowpits from sites with accumulation rates between 24 and 172 kg m−2 a−1 were sampled to depths of 150 to 300 cm. At sites from the continental interior (low accumulation, < 55 kg m−2 a−1), nitrate mass fraction is generally > 200 ng g−1 in surface snow and decreases quickly with depth to < 50 ng g−1. Considerably increasing values of δ15N of nitrate are also observed (16–461 ‰ vs. air N2), particularly in the top 20 cm, which is consistent with predicted fractionation constants for the photolysis of nitrate. The δ18O of nitrate (17–84 ‰ vs. VSMOW (Vienna Standard Mean Ocean Water)), on the other hand, decreases with increasing δ15N, suggestive of secondary formation of nitrate in situ (following photolysis) with a low δ18O source. Previous studies have suggested that δ15N and δ18O of nitrate at deeper snow depths should be predictable based upon an exponential change derived near the surface. At deeper depths sampled in this study, however, the relationship between nitrate mass fraction and δ18O changes, with increasing δ18O of nitrate observed between 100 and 200 cm. Predicting the impact of post-depositional loss, and therefore changes in the isotopes with depth, is highly sensitive to the depth interval over which an exponential change is assumed. In the snowpits collected closer to the coast (accumulation > 91 kg m−2 a−1), there are no obvious trends detected with depth and instead seasonality in nitrate mass fraction and isotopic composition is found. In comparison to the interior sites, the coastal pits are lower in δ15N (−15–71 ‰ vs. air N2) and higher in δ18O of nitrate (53–111 ‰ vs. VSMOW). The relationships found amongst mass fraction, δ15N, δ18O and Δ17O (Δ17O = δ17O–0.52 × δ18O) of nitrate cannot be explained by local post-depositional processes alone, and are instead interpreted in the context of a primary atmospheric signal. Consistent with other Antarctic observational and modeling studies, the isotopic results are suggestive of an important influence of stratospheric ozone chemistry on nitrate formation during the cold season and a mix of tropospheric sources and chemistry during the warm season. Overall, the findings in this study speak to the sensitivity of nitrate isotopic composition to post-depositional processing and highlight the strength of combined use of the nitrogen and oxygen isotopes for a mechanistic understanding of this processing.
Observations of atmospheric mercury in China: a critical review
Authors: Fu X. W. , Zhang H. , Yu B. , Wang X. , Lin C.-J. , Feng X. B.
Published: August 2015

Abstract. China presently contributes the largest amount of anthropogenic mercury (Hg) emission into the atmosphere in the world. Over the past decade, numerous studies have been conducted to characterize the concentration and forms of atmospheric Hg in China, which provide insights into the spatial and temporal distributions of atmospheric Hg through ground-based measurements at widely diverse geographical locations and during cruise and flight campaigns. In this paper, we present a comprehensive review of the state of understanding in atmospheric Hg in China. Gaseous elemental mercury (GEM) and particulate-bound mercury (PBM) measured at the remote sites in China are substantially elevated compared to the background values in the Northern Hemisphere. In Chinese urban areas, the highly elevated GEM, PBM and gaseous oxidized mercury (GOM) were mainly derived from local anthropogenic Hg emissions, whereas regional anthropogenic emissions and long-range transport from domestic source regions are the primary causes of the elevated GEM and PBM concentrations at remote sites. Using 7–9 years of continuous observations at a remote site and an urban site, a slight increase in atmospheric GEM (2.4–2.5 % yr−1) was identified (paired samples test: p < 0.01), which is in agreement with the increasing domestic anthropogenic emissions. Anthropogenic GEM emission quantity in China estimated through the observed GEM / CO concentration ratios ranged from 632 to 1138 t annually over the past decade, 2–3 times larger than published values using emission activity data. Modeling results and filed measurements show dry deposition is the predominant process for removing Hg from the atmosphere, 2.5–9.0 times larger than wet deposition, due to the elevated atmospheric GEM and PBM concentrations that facilitate dry deposition to terrestrial landscapes. Further studies to reconcile the observed and simulated Hg concentrations, to understand the impact of domestic emission reduction on Hg concentration and deposition and to delineate the role of Hg emission and deposition of China in the global Hg biogeochemical cycle, are needed.
New insight into the spatiotemporal variability and source apportionments of C1–C4 alkyl nitrates in Hong Kong
Authors: Ling Z. H. , Guo H. , Simpson I. J. , Saunders S. M. , Lam S. H. M. , Lyu X. P. , Blake D. R.
Published: August 2015

Abstract. Alkyl nitrates (RONO2) were measured concurrently at a mountain site (TMS) and an urban site (TW) at the foot of the same mountain in Hong Kong from September to November 2010, when high O3 mixing ratios were frequently observed. The abundance and temporal patterns of five C1–C4 RONO2 and their parent hydrocarbons (RH), the RONO2/RH ratios and photochemical age of air masses at TMS differed from those at TW, reflecting different contributions of direct emissions and secondary formation of RONO2 at the two sites. Relative to 2-BuONO2/n-butane, the measured ratios of C1–C2 RONO2/RH at the two sites exhibited significant positive deviations from pure photochemical (PP) curves and background initial ratio (BIR) curves obtained from laboratory kinetic data, suggesting that background mixing ratios had a significant influence on the RONO2 and RH distributions. In contrast to the C1–C2 RONO2/RH ratios, the evolution for the measured ratios of C3 RONO2/RH to 2-BuONO2/n-butane agreed well with the ratio distributions in the PP and BIR curves at the two sites. Furthermore, the ratios of 1-/2-PrONO2 and yields of 1- and 2-PrONO2 suggested that the C3 RONO2 were mainly from secondary formation at TMS, whereas secondary formation and other additional sources had a significant influence on C3 RONO2 mixing ratios at TW. The source apportionment results confirmed that secondary formation was the dominant contributor to all the RONO2 at TMS, while most of the RONO2 at TW were from secondary formation and biomass burning. The findings of the source apportionments and photochemical evolution of RONO2 are helpful to evaluate photochemical processing in Hong Kong using RONO2 as an indicator.
Investigations of boundary layer structure, cloud characteristics and vertical mixing of aerosols at Barbados with large eddy simulations
Authors: Jähn M. , Muñoz-Esparza D. , Chouza F. , Reitebuch O.
Published: August 2015

Abstract. Large eddy simulations (LES) are performed for the area of the Caribbean island Barbados to investigate island effects on boundary layer modification, cloud generation and vertical mixing of aerosols. Due to the presence of a topographically structured island surface in the domain center, the model setup has to be designed with open lateral boundaries. In order to generate inflow turbulence consistent with the upstream marine boundary layer forcing, we use the cell perturbation method based on finite amplitude perturbations. In this work, this method is for the first time tested and validated for moist boundary layer simulations with open lateral boundary conditions. Observational data obtained from the SALTRACE field campaign is used for both model initialization and a comparison with Doppler wind lidar data. Several numerical sensitivity tests are carried out to demonstrate the problems related to "gray zone modeling" when using coarser spatial grid spacings beyond the inertial subrange of three-dimensional turbulence or when the turbulent marine boundary layer flow is replaced by laminar winds. Especially cloud properties in the downwind area west of Barbados are markedly affected in these kinds of simulations. Results of an additional simulation with a strong trade-wind inversion reveal its effect on cloud layer depth and location. Saharan dust layers that reach Barbados via long-range transport over the North Atlantic are included as passive tracers in the model. Effects of layer thinning, subsidence and turbulent downward transport near the layer bottom at z ~ 1800 m become apparent. The exact position of these layers and strength of downward mixing is found to be mainly controlled atmospheric stability (especially inversion strength) and wind shear. Comparisons of LES model output with wind lidar data show similarities in the formation of the daytime convective plume and the mean vertical wind structure.