bluuebunny/crossref_metadata_2025 huggingface dataset:
New power sharing scheme with correlation control for input‐parallel–output‐series‐based interleaved resonant inverters
Authors: Liu Junfeng , Cheng Ka Wai Eric
Published: April 2014

High‐frequency AC power distribution system reveals more merits than low or medium frequency system. The resonant inverter in series or parallel is commonly used as high‐frequency power source. However, the topology design and control scheme are complicated for high frequency source formed by multiple resonant inverters. In this study, a modified input‐parallel–output‐serial topology with the unified resonant tank is presented to boost output capacity and optimise synchronisation. A small signal‐based control scheme is analysed for power sharing and magnitude control. Besides, a correlation control is adopted for harmonics suppression and efficiency improvement over a wide operating scope. In a word, the proposed topology and control scheme provide high quality output, flexible power capacity and wide operation range. The performance is evaluated by a two‐module prototype with a rated output power of 120 W and output frequency of 25 kHz. The experimental results are accorded with simulation and theoretical analysis.
Instantaneous power‐based current control scheme for VAR compensation in hybrid AC/DC networks for smart grid applications
Authors: Shanthi Pandurangan , Govindarajan Uma , Parvathyshankar Deivasundari
Published: April 2014

An important feature of grid‐connected DC microgrids is the ability to inject or suck power from the grid based on the generation and loading conditions. Power flow from the AC to DC grid is important to cover any deficiency in the demand in DC grid. Power flow from the DC to AC grid is needed when there is an excess power from renewable energy sources on the DC bus. To allow this bidirectional power flow, a pulse‐width modulation controlled voltage source converter is used as an interface between the DC microgrid and the AC main grid. The bidirectional converter controls the active power transferred in both directions while operating at unity power factor. In this study, a current control approach based on the instantaneous synchronous detection theory has been used to control the power flow in both directions. The proposed current control scheme is verified through MATLAB simulation and the simulated results are also validated experimentally using a prototype controlled by dSPACE digital signal processor. The simulated and the experimental results show that the proposed scheme offers regulated DC grid voltage and nearly unity power factor for wide load variations. Results have proven excellent performance in steady and transient states.
Distribution static compensator based on an improved direct power control strategy
Authors: Luo An , Xiao Huagen , Ma Fujun , Shuai Zhikang , Wang Yichao
Published: April 2014

In this study, an improved direct power control strategy based on the deadbeat current control with adaptive ability is proposed for three‐phase distribution static compensator (DSTATCOM), whose current references are directly computed by power reference and power feedback according to the instantaneous power theory, and the deadbeat current control is used to assure the current waveform quality. The improved direct power control strategy does not need phase‐locked loop, and not exists the coupling among the control variables of DSTATCOM. Moreover, the proposed control strategy has good dynamic response and adaptive ability, and its design process is very simple. At last, the feasibility and validity of the proposed control strategy are verified by the simulation and experiment results.
Reconfiguration of semi‐cascaded multilevel inverter to improve systems performance parameters
Authors: Banaei Mohamad Reza , Jannati Oskuee Mohammad Reza , Khounjahan Hossein
Published: April 2014

In this study, a new topology of semi‐cascaded multilevel inverter is proposed which is a proper alternative to be used in medium voltage applications. This structure consists of series connected sub‐multilevel inverters blocks. The proposed topology is based on the connections of several cell units in an appropriate scheme with the help of six power switches. Compared to the traditional cascaded multilevel inverter, in suggested topology the number of switches, inverter cost and installation area are reduced significantly. Also, in comparison with semi‐cascaded multilevel inverter, the proposed inverter works with lower total peak inverse voltage. The proposed inverter is able to be used as an asymmetrical inverter. To verify the operation and good performance of the proposed inverter the simulation and experimental results are obtained.
Synchronous rectifier driving circuit based on voltage‐driven method with energy recovery
Authors: Asghari Amin , Farzanehfard Hosein
Published: April 2014

A new synchronous rectifier (SR) gate drive circuit is presented in this study. The proposed SR driver generates the driving signal according to the SR voltage polarity without using any external control signal. Also, it can turn off the SR with delay and keeps the SR on after its drain source voltage becomes positive. In addition, this driver recovers part of the driving energy in a resonant manner. The proposed SR driving circuit is suitable for some zero voltage transition (ZVT) synchronous buck converters. It can also be used for some high‐frequency resonant converters and high‐frequency discontinuous conduction mode pulse‐width modulation circuits. In this study, the proposed driver is applied to a ZVT synchronous buck converter and the presented experimental results confirm the theoretical analysis.
Pulse width modulation schemes enabling single DC power source driven dual two‐level voltage source inverter with single voltage source inverter switching
Authors: Srinivas Srirama , Kalaiselvi Jeyaraman
Published: April 2014

Three‐level voltage space phasor can be obtained using a dual two‐level voltage source inverter (VSI). Two zero sequence voltage elimination pulse width modulation (PWM) switching variants are proposed in this paper for complete elimination of zero sequence voltage (ZSV) in the dual‐VSI scheme. Both the PWM variants are designed in such a way that only one inverter is switched at any instant of time; to ensure that switching power losses in the dual‐VSI is limited to one inverter only at any instant of time. Analytical expressions for the dwell times of the dual‐VSI are developed and presented that successfully forces the ZSV in the dual‐VSI to zero; at all instants of time. As a result, both the PWMs facilitate the dual‐VSI to be driven from a single DC power source only. The implementation of the proposed PWM algorithms is greatly simplified and involves just the use of instantaneous magnitudes of the reference space vector. The implementation of PWMs totally avoids the time consuming task of sector identification and do not use look up tables. The PWMs proposed in this paper are first analysed, simulated using MATLAB/SIMULINK and then verified experimentally to validate the proposed PWMs.
Applying bilinear time‐optimal control system in boost converters
Authors: Nazarzadeh Jalal , Javad Jafarian Mohammad
Published: April 2014

A new development of time‐optimal control in bilinear systems is introduced here and applied to a boost converter. By an analytic approach, time‐optimal control system for output regulation is employed in bilinear systems and an optimal switching surface is obtained. Transient response of the time‐optimal system is described to eliminate any output disturbances in minimum time. Some experimental and numerical results are illustrated that the time interval for output regulation and transient performances of a boost converter using the proposed technique in comparison with other classical method such as sliding mode control are effectively improved.
Zero‐voltage transition bridgeless single‐ended primary inductance converter power factor correction rectifier
Authors: Mahdavi Mohammad , FarzanehFard Hosein
Published: April 2014

In this study, a new zero‐voltage transition (ZVT) bridgeless single‐ended primary inductance converter power factor correction converter is introduced. The proposed converter has only two semiconductor elements in the current path at any time. Therefore the conduction losses in this converter are reduced in comparison with conventional SEPIC PFC rectifier. Also, in the proposed converter, ZVT soft switching technique is applied to improve the efficiency. The principle of the operation, design procedure and simulation results are presented. A 450 W prototype of this converter is implemented and the experimental results are presented to demonstrate the feasibility of the proposed technique.
Generalised design method for improving control quality of hybrid active power filter with injection circuit
Authors: Nguyen Trung Nhan , Luo An , Shuai Zhikang , Chau Minh Thuyen , Li Mingfei , Zhou Leming
Published: April 2014

Harmonic suppression is an important and challenging issue in electrical power systems and can be resolved by using hybrid active power filters with injection circuit (IHAPFs). In existing IHAPF systems, however, it is usually assumed that all parameters are determined accurately and unchanged over time, which is not true in real situations. It is well known that variations of system parameters may seriously degrade the performance of IHAPF systems. To obtain both efficiency and robustness, this study proposes a novel method for the generalised controller design of a three‐phase IHAPF system which can deal with deviations of system parameters. An optimum way to determine the stability bounds under various system parameters cases is introduced. The assessment of the stability bounds is based on the Routh criterion through solving the characteristic equation of the closed‐loop control system. Simulations and experimental results are presented to validate the correctness and effectiveness of the proposed design method for controller used in IHAPF system.
Buck converter‐based power supply design for low power light emitting diode lamp lighting
Authors: Singh Bhim , Shrivastava Ashish
Published: April 2014

This study deals with the analysis and implementation of an HPF (high power factor) single‐stage, single switch buck converter‐based power supply design for an LED (light emitting diode) lamp load of 13 W operated at the universal ac mains. In general purpose lighting applications, a buck converter is a good candidate for power factor correction with low component count and reduced cost. In low‐power lighting, it is a tough task to control the THDi (total harmonic distortion) of ac mains current under the limits of strict international standards such as IEC‐61000‐3‐2 with universal ac mains for class D equipments. In the proposed optocouplerless topology, HPF operation at input ac mains is achieved by operating the buck ac–dc converter in continuous conduction mode. The design, modelling and simulation of the proposed topology are executed using MATLAB‐Simulink and sim‐power system toolboxes. A prototype of the power supply for LED lamp is developed for multiple LEDs connected in series configuration. The efficiency of the proposed LED lamp driver is observed as 83.76% at rated voltage of 220 V and the THD of ac mains current less than 17.27% for a wide range of voltages of 90–270 V.
Analysis of dynamics of fluid power drive‐trains for variable speed wind turbines: parameter study
Authors: Laguna Antonio Jarquin , Diepeveen Niels F.B. , van Wingerden Jan Willem
Published: April 2014

In the pursuit of making wind energy technology more economically attractive, fluid power technology for the transmission of wind energy is being developed by several parties all over the world. This study presents a dynamic model of a fluid power transmission for the variable speed wind turbines and shows a parametric study on the dynamic behaviour below the rated wind speed. A pressure control strategy is proposed to achieve a variable speed operation of the rotor while using a fixed speed generator. The rotor of a five megawatt reference turbine is used to perform the time domain simulations. Different values of the hydraulic line length and transmission efficiency are considered for the same wind conditions and the results are compared with the response of the reference gearbox drive train. The results show that the amount of oil in the hydraulic drivetrain has an important influence on the first natural frequency of the transmission and the pipeline dynamics become more relevant for the longer transmission lines. Lowering the volumetric efficiency of the hydraulic motor leads to an additional damping of the pressure fluctuation, however, its influence is minor and unlikely to be advantageous when compared with the power loss.
Subsynchronous resonance characteristics in presence of doubly‐fed induction generator and series compensation and mitigation of subsynchronous resonance by proper control of series capacitor
Authors: Xie Hailian , Li Bin , Heyman Carl , de Oliveira Marcio M. , Monge Mauro
Published: April 2014

This study investigates the subsynchronous resonance (SSR) characteristics in the systems with doubly‐fed induction generators and series compensated ac lines, by using the transfer‐function analysis approach. A new SSR mitigation method by a proper control of a series capacitor (SC) is also presented with the effectiveness evaluated. SSR mitigation by a proper control of the SC is attractive since it does not incur any additional cost. This shows that there are no technical obstacles to use a series compensation as a means to improve the power transmission capability in the systems with a high wind energy penetration.
Monitoring resonant frequencies and damping values of an offshore wind turbine in parked conditions
Authors: Devriendt Christof , Weijtjens Wout , El‐Kafafy Mahmoud , De Sitter Gert
Published: April 2014

This study shows the first results of a long‐term monitoring campaign on an offshore wind turbine in the Belgian North Sea. It focuses on the continuous monitoring of the resonant frequencies and damping values of the most dominant modes of the support structure. These parameters allow to better understand the dynamics of offshore wind turbines and are crucial in the fatigue assessment during the design phase. They can also help to minimise operation and maintenance (O&M) costs and to assess the lifetime of the offshore wind turbines structures during their operation. To do an accurate continuous monitoring of these parameters, a state‐of‐the‐art operational modal analysis technique has been automated, so that no human‐interaction is required and the system can track small changes in the dynamic behaviour of the offshore wind turbine. The study will analyse the resonant frequencies and damping values of the most dominant modes shapes while the wind turbine is in parked conditions.
Operational strategies for offshore wind turbines to mitigate failure rate uncertainty on operational costs and revenue
Authors: Dinwoodie Iain Allan , McMillan David
Published: April 2014

Several operational strategies for offshore wind farms have been established and explored in order to improve understanding of operational costs with a focus on heavy lift vessel strategies. Additionally, an investigation into the uncertainty surrounding failure behaviour has been performed identifying the robustness of different strategies. Four operational strategies were considered: fix on fail, batch repair, annual charter and purchase. A range of failure rates have been explored identifying the key cost drivers and under which circumstances an operator would choose to adopt them. When failures are low, the fix on fail and batch strategies perform best and allow flexibility of operating strategy. When failures are high, purchase becomes optimal and is least sensitive to increasing failure rate. Late life failure distributions based on mechanical and electrical components behaviour have been explored. Increased operating costs because of wear‐out failures have been quantified. An increase in minor failures principally increase lost revenue costs and can be mitigated by deploying increased maintenance resources. An increase in larger failures primarily increases vessel and repair costs. Adopting a purchase strategy can negate the vessel cost increase; however, significant cost increases are still observed. Maintenance actions requiring the use of heavy lift vessels, currently drive train components and blades are identified as critical for proactive maintenance to minimise overall maintenance costs.
Comparison of methods for wind turbine condition monitoring with SCADA data
Authors: Wilkinson Michael , Darnell Brian , van Delft Thomas , Harman Keir
Published: April 2014

Wind turbine operational costs can be reduced by monitoring the condition of major components in the drivetrain. SCADA‐based condition monitoring is attractive because the data are already collected, resulting in rapid deployment and modest set‐up cost. Three SCADA‐based monitoring methods were reviewed: signal trending; self‐organising maps and physical model. The physical model was identified as being the most reliable at predicting impending component failures. A validation study on this method using five operational wind farms showed that it is possible to achieve a high detection rate and good detection accuracy. An advance detection period of between 1 month and 2 years was achieved by the method. The study has also highlighted limitations and areas for further development.
Hydrothermal synthesis of chain‐like nickel microstructures with enhanced magnetic properties
Authors: Xu Chunju , Wang Yujie , Chen Huiyu , Zhao Guizhe , Liu Yaqing
Published: April 2014

Novel nickel chains assembled by submicrometre‐sized spheres have been synthesised via a simple hydrothermal approach. Hydrazine was employed as both a ligand and a reducing agent, and polyvinylpyrrolidone (PVP) was used as the soft template. The nickel products were characterised by means of X‐ray diffraction, scanning electron microscopy and transmission electron microscopy techniques. It was found that the amount of PVP and its long molecular chains played important roles in the formation of such microchains with a few branches. Magnetic measurement by a vibrating sample magnetometer illustrated that the nickel chains possessed ferromagnetic behaviour and significantly enhanced coercivity of 195 Oe compared with that of the bulk counterpart. The presented hydrothermal process could be adopted to fabricate chain‐like micro/nanostructures of other materials.
Polystyrene microspheres‐templated preparation of hierarchical porous modified red mud with high rhodamine B dye adsorption performance
Authors: Cao Jianliang , Wang Yan , Yan Zhaoli , Li Gaojie
Published: April 2014

Modified red mud (MRM‐PS) with a hierarchical macroporous–mesoporous structure was prepared via a template synthesis method by using polystyrene (PS) microspheres and waste red mud. The textural and morphology of the as‐prepared MRM‐PS adsorbents were characterised by X‐ray diffraction, scanning electron micrographs, transmission electron microscopy and N2 sorption techniques. The analysis results revealed a hierarchical macroporous–mesoporous nanoparticle system with high surface area and uniform pore‐size distribution. The results of adsorption performance measurements showed that the rhodamine B adsorption on the prepared MRM‐PS adsorbent was a fast process and the equilibrium was reached in 10 min. What is more, the adsorption capacity of MRM‐PS was found to be 59.37 mg dye·g−1 of adsorbent at 25°C and pH = 1. Thus, utilisation of industrial solid wastes such as red mud for the treatment of wastewater could help in the abatement of environmental pollution, in solving both solid waste disposal and liquid waste problems.
Travelling wave magnetic valveless micropump driven by rotating integrated magnetic arrays
Authors: Ye Weixiang , Zhang Wei , Wang Cheng , Li Wenbin , Yue Zhao , Liu Guohua
Published: April 2014

A novel magnetic valveless micropump is proposed for microfluidic applications. Two integrated NdFeB permanent magnetic arrays were used to generate a travelling wave on the top wall of the elastic microchannel, and then the liquid particles were transported along with the travelling wave in the microchannel. The characteristics tested at different frequencies demonstrate that the magnetic micropump has a much higher driving efficiency than the piezoelectric micropump with the same saw‐toothed microchannel. By using a low power supply (3.7 V Vp‐p, 185 mW), the magnetic micropump significantly improves the maximum flow rate and back pressure to 184.25 μl/min and 1.28 kPa with the microchannel of 200 µm width.
Preparation and tribological properties of nanoaluminium fluoride as additives to base oil
Authors: Xue Maoquan , Tang Hua , Song Haojie , Li Changsheng
Published: April 2014

Cubical AlF3 nanoparticles have been successfully synthesised by immersing Ti3AlC2 powders in hydrofluoric acid‐assisted solvothermal reaction. The as‐prepared products are characterised by an X‐ray diffractometer and scanning electron microscopy. The results showed that the AlF3 nanoparticles have a cubical structure and the sizes of nanoparticles are about 100 nm in side length. The tribological properties of cubical AlF3 nanoparticles as a lubrication additive in 100SN base oil were investigated by a UMT‐2 ball‐on‐disc friction and wear tester. The wear scars were measured by a common optical microscope. The results show that under determinate conditions, the friction coefficient of the base oil containing AlF3 nanoparticles is lower than that of pure base oil, and the base oil containing 1 wt% AlF3 samples presented good tribological performance under the load of 15 N. The formation of tribofilm on the rubbing surface could explain the good friction of AlF3 nanoparticles as additives.
Anterior-only Partial Sacrectomy for en bloc Resection of Locally Advanced Rectal Cancer
Authors: Roldan Hector , Perez-Orribo Luis F. , Plata-Bello Julio M. , Martin-Malagon Antonio I. , Garcia-Marin Victor M.
Published: April 2014

Study Design

Case report.

Objective

The usual procedure for partial sacrectomies in locally advanced rectal cancer combines a transabdominal and a posterior sacral route. The posterior approach is flawed with a high rate of complications, especially infections and wound-healing problems. Anterior-only approaches have indirectly been mentioned within long series of rectal cancer surgery. We describe a case of partial sacrectomy for en bloc resection of a locally advanced rectal cancer with invasion of the low sacrum through a combined transabdominal and perineal approach without any posterior incision.

Methods

Through a midline laparotomy, the tumor was dissected and the sacral osteotomy was performed. Once the sacrum was mobile, the muscular attachments to its posterior wall were cut through the perineal approach. This latter route was also used to remove the whole specimen.

Results

The postoperative period was uneventful in terms of infection and wound healing, but the patient developed right foot dorsiflexion paresis that completely disappeared in 1 month. Resection margins were negative. After a follow-up of 18 months, the patient has no local recurrence but presented lung and liver metastases.

Conclusion

In cases of rectal cancer involving the low sacrum, the combination of a transabdominal and a perineal route to carry out the partial sacrectomy is a feasible approach that avoids changes of surgical positioning and the morbidity related to posterior incisions. This strategy should be considered when deciding on undertaking partial sacrectomy in locally advanced rectal cancer.
Genetic control of flowering in spotted gum, Corymbia citriodora subsp. variegata and C. maculata
Authors: Abasolo Myralyn , Lee David J. , Brooks Lyndon , Raymond Carolyn , Shepherd Mervyn
Published: April 2014

Genetically controlled asynchrony in anthesis is an effective barrier to gene flow between planted and native forests. We investigated the degree of genetically controlled variation in the timing of key floral developmental stages in a major plantation species in subtropical Australia, Corymbia citriodora subsp. variegata K.D. Hill and L.A.S Johnson, and its relative C. maculata K.D. Hill and L.A.S. Johnson. Flowering observations were made in a common garden planting at Bonalbo in northern New South Wales in spring on 1855 trees from eight regions over three consecutive years, and monthly on a subset of 208 trees for 12 months. Peak anthesis time was stable over years and observations from translocated trees tended to be congruent with the observations in native stands, suggesting strong genetic control of anthesis time. A cluster of early flowering provenances was identified from the north-east of the Great Dividing Range. The recognition of a distinct flowering race from this region accorded well with earlier evidence of adaptive differentiation of populations from this region and geographically-structured genetic groupings in C. citriodora subsp. variegata. The early flowering northern race was more fecund, probably associated with its disease tolerance and greater vigour. Bud abundance fluctuated extensively at the regional level across 3 years suggesting bud abundance was more environmentally labile than timing of anthesis. Overall the level of flowering in the planted stand (age 12 years) was low (8–12% of assessed trees with open flowers), and was far lower than in nearby native stands. Low levels of flowering and asynchrony in peak anthesis between flowering races of C. citriodora subsp. variegata may partially mitigate a high likelihood of gene flow where the northern race is planted in the south of the species range neighbouring native stands.
Seasonal variation in the nitrogen nutrition and carbon assimilation in wild and cultivated Aspalathus linearis (rooibos tea)
Authors: Lötter Daleen , Archer van Garderen Emma , Tadross Mark , Valentine Alexander J.
Published: April 2014

The Fynbos Biome of southern Africa is a Mediterranean-climate ecosystem with highly infertile soil. It is home to the endemic leguminous shrub Aspalathus linearis (rooibos tea), which is both an invaluable wild resource and commercially cultivated plant. Wild rooibos has a narrow geographic range and is confined to mountain ranges of the Cederberg Region. Under projected climate change, warmer and more arid conditions may place additional pressure on these range-restricted plants to survive in an already resource-limited environment. To understand the adaptive strategies that may allow rooibos to persist in its habitat under future climate change, the present study evaluated changes in the photosynthetic activity and nutrient cycling of wild and cultivated A. linearis, at the temperature and rainfall extremes of summer and winter. Wild and cultivated rooibos tea had different methods of adapting to nitrogen (N) nutrition and carbon (C) assimilation during wet and dry seasons. In particular, the wild plants were better able to tolerate summer drought by increased water use efficiency and maintaining higher levels of biological N2 fixation than was the cultivated tea.
Dispersal potential of Scaevola crassifolia (Goodeniaceae) is influenced by intraspecific variation in fruit morphology along a latitudinal environmental gradient
Authors: Guja Lydia K. , Merritt David J. , Dixon Kingsley W. , Wardell-Johnson Grant
Published: April 2014

Dispersal of plant propagules by ocean currents can result in long-distance dispersal and is important for the persistence of coastal species. However, the ability of such species to disperse via the ocean is often unknown because there is relatively little evidence that demonstrates that seeds or fruits can float and survive for extended periods in seawater. Furthermore, the seed or fruit traits, and intraspecific variation in these traits, that facilitate buoyancy remain largely unidentified. The genus Scaevola (L.) contains several widespread coastal species that may be capable of oceanic dispersal, such as S. crassifolia (Labill). We collected fruits of S. crassifolia along 700 km of a latitudinal environmental gradient. These fruits were used to determine the influence of fruit morphology and anatomy on fruit buoyancy. Morphological and anatomical variation in S. crassifolia was associated with dispersal potential. Our empirical data demonstrated that fruits with larger aeriferous mesocarp layers have greater buoyancy and, therefore, enhanced capacity for long range oceanic dispersal. Of three characters hypothesised to affect buoyancy (aeriferous mesocarp, air pockets in empty locules, and number of vascular cavities), only the properties of the mesocarp were significant. Intraspecific variation can significantly affect dispersal potential, and should not be overlooked in dispersal ecology.
Deposition and dissolution of metal sulfide layers at the Hg electrode surface in seawater electrolyte conditions
Authors: Milanović Ivana , Krznarić Damir , Bura-Nakić Elvira , Ciglenečki Irena
Published: April 2014

Environmental context The electrochemical detection of many sulfur compounds in natural waters is based on the deposition of a HgS layer at the Hg electrode. In samples containing metal ions in excess of sulfide species, electrochemical exchange reactions between the HgS and the metal ion produce metal-sulfide voltammetric peaks. These peaks can easily be misinterpreted as dissolved sulfide species, and hence do not reflect the bulk state of the solution. Abstract Cyclic voltammetry on a Hg electrode was used to investigate the influence of metal ion (Zn, Cd, Cu, Fe, Pb, Co) on HgS deposition–dissolution in seawater conditions. Due to the exchange of electrons between Hg2+ from a HgS layer and free metal (M2+) from the solution (HgSlayer + M2+ + 2e– ↔ MSlayer + Hg0), the Hg electrode becomes the site for surface metal sulfide (MS) formation. The exchange reaction is reversible, and the surface-formed MS layer reduces at a more negative potential than HgS (MSlayer + 2e– + H+ → M0 + HS). The potentials of both electrode reactions, and the formation and reduction of the MS layer, are determined by the MS solubility product. In solutions containing excess of the free metal ions in comparison to the free sulfide, the exchange reaction produces MS voltammetric peaks, which can be misrepresented for the dissolved sulfide species. This research indirectly confirmed that the FeS electrochemical signal, usually recorded in an iron- and sulfide-rich environment at ~–1.1V v. Ag/AgCl, is not due to FeS reduction. The connection between the studied MS reduction peak potentials and the solubility products shows that the FeS layer formed by an electrochemical exchange reaction with HgS should be reduced at the Hg surface ~100mV more negative than free Fe2+.
Constant current chronopotentiometric stripping characterisation of organic matter in seawater from the northern Adriatic, Croatia
Authors: Strmečki Slađana , Dautović Jelena , Plavšić Marta
Published: April 2014

Environmental context
We determined seasonal changes in the organic matter content of the northern Adriatic with newly applied electrochemical techniques able to measure catalytically active organics. The inflow of the Po River and its nutrient load are responsible for the observed changes in the type and concentrations of organic matter in the area.

Abstract
Catalytically active polysaccharides (Cat PSs) and nitrogen-containing polymeric organic material (N-POM) were determined in seawater from the northern Adriatic station ST101. Catalytically active organics were measured by applying electrochemical methods of adsorptive transfer chronopotentiometric stripping with medium exchange and chronopotentiometric stripping in unmodified seawater. Their concentrations were expressed in milligrams per cubic decimetre–3--> of equivalents of the model calibrating substances, polysaccharide xanthan and protein human serum albumin. The optimal electroanalytical conditions for determination of Cat PSs in seawater were evaluated and defined. Seasonal changes of Cat PSs and N-POM were observed during the period 2011–2013. The highest values were determined in the spring–summer period and the lowest in winter. Cat PSs and N-POM were present in both the dissolved and particulate organic carbon fractions. Cat PSs and N-POM showed a statistically significant positive correlation with the concentrations of surface-active substances. A weak but statistically significant correlation was found between Cat PSs and dissolved organic carbon concentrations. Copper complexing capacities in the period 2011–2013 were in the range of 41–130nmoldm–3.
Cytosolic alkalisation and nitric oxide production in UVB-induced stomatal closure in Arabidopsis thaliana
Authors: Ge Xiao-Min , Zhu Yan , He Jun-Min
Published: April 2014

The role and the interrelationship of cytosolic alkalisation and nitric oxide (NO) in UVB-induced stomatal closure were investigated in Arabidopsis thaliana (L.) Heynh. by stomatal bioassay and laser-scanning confocal microscopy. In response to 0.5 W m–2 UVB radiation, the rise of NO levels in guard cells occurred after cytosolic alkalisation but preceded stomatal closure. UVB-induced NO production and stomatal closure were both inhibited by NO scavengers, nitrate reductase (NR) inhibitors and a Nia2–5/Nia1–2 mutation, and also by butyrate. Methylamine induced NO generation and stomatal closure in the wild-type but not in the Nia2–5/Nia1–2 mutant or wild-type plants pretreated with NO scavengers or NR inhibitors while enhancing the cytosolic pH in guard cells under light. NO generation in wild-type guard cells was largely induced after 60 min of UVB radiation. The defect in UVB-induced NO generation in Nia2–5/Nia1–2 guard cells did not affect the changes of guard cell pH before 60 min of UVB radiation, but prevented the UVB-induced cytosolic alkalisation after 60 min of radiation. Meanwhile, exogenous NO caused a marked rise of cytosolic pH in guard cells. Together, our results show that cytosolic alkalisation and NR-dependent NO production coordinately function in UVB signalling in A. thaliana guard cells.
SsHKT1;1 is a potassium transporter of the C3 halophyte Suaeda salsa that is involved in salt tolerance
Authors: Shao Qun , Han Ning , Ding Tonglou , Zhou Feng , Wang Baoshan
Published: April 2014

SsHKT1;1, a HKT1 homologue, was isolated from the C3 halophyte Suaeda salsa L. and its ion transport properties were investigated in heterologous systems. The expression of SsHKT1;1 suppressed a K+ transport-defective phenotype of the yeast strain CY162 (Δtrk1Δtrk2), suggesting the enhancement of K+ uptake with SsHKT1;1. However, it did not suppress the salt-sensitive phenotype of the yeast strain G19 (Δena1–4), which lacks a major component of Na+ efflux. Transgenic Arabidopsis thaliana (L.) Heynh. plants overexpressing SsHKT1;1 showed enhanced salt tolerance and increased shoot K+ concentration, whereas no significant changes in shoot Na+ concentration were observed. S. salsa was also used to investigate K+ uptake properties under salinity. The K+ transporters in the roots selectively mediated K+ uptake irrespective of external Na+ and their inhibitor did not affect Na+ uptake at low K+. Thus, both molecular and physiological studies provide strong in vivo evidence that SsHKT1;1 mainly acts as a potassium transporter in heterologous expression systems and S. salsa, and that it is involved in salt tolerance by taking part in the maintenance of cytosolic cation homeostasis, particularly, in the maintenance of K+ nutrition under salinity.
Distribution of cortical granules and meiotic maturation of canine oocytes in bi-phasic systems
Authors: Apparicio Maricy , Mostachio Giuliano Q. , Motheo Tathiana F. , Alves Aracelle E. , Padilha Luciana , Pires-Butler Eliandra A. , Savi Paula A. P. , Uscategui Ricardo A. R. , Luvoni Gaia C. , Vicente Wilter R. R.
Published: April 2014

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72 h in base medium (BM) with 10 IU mL–1 human chorionic gonadotrophin (hCG), 1 μg mL–1 progesterone (P4) and 1 μg mL–1 oestradiol (E2); in bi-phasic System B oocytes were matured for 48 h in BM with hCG and for 24 h in BM with P4; in bi-phasic System C oocytes were matured for 48 h in BM with hCG, P4 and E2, and for 24 h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P < 0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P < 0.001). The stage of the oestrous cycle did not influence maturation rates.
The Self among its objects
Authors: Pietrzak Wit
Published: April 2014

This article explores W. B. Yeats’s “A Dialogue of Self and Soul” as a space of irresolvable tension between the destitution of bodily life, imaged forth by the Soul, and the capacity of poetry to compensate for that destitution, which is projected by the Self. The analysis shows the poem to be a dense structure of mirror-like internal relations, primarily between the Self and Soul but also between the Self and the objects it chooses as opposition to the Soul’s vision. These lines of reflection, which carry the poem’s imaginative energy, will be investigatedvis-à-visJacques Lacan’s theorisation of the ideas of the gaze andobjet petit a.
Lexical bundles and phrase frames in the language of hotel websites
Authors: Fuster Márquez Miguel
Published: April 2014

Hotel websites have been researched from the perspective of vocabulary and discourse. However, little attention has been paid to lexical bundles and phrase frames in these text types. In this paper, I show by means of an empirical analysis that such word sequences characterise these sites as a highly specialised domain. With this aim in mind, I have analysed a corpus of British hotel websites containing 242,000 words from a database, currently being compiled by the research group COMETVAL. I show that bundles and frames follow very similar principles but differ in flexibility. Moreover, the existence of frames shows collaboration between the idiom and open-choice principle. In fact, most bundles in my corpus are instances of phrase frames.
Developing comprehensive criteria of adequacy
Authors: Wray Alison
Published: April 2014

Butler (2009a, b) argues that an adequate model of the language system should
accommodate cognitive, sociocultural, discoursal, acquisitional, typological
and diachronic dimensions, and observational evidence from corpora, experiments
and intuition. This paper asks if such reconciliation is possible. It argues
that language is composed of accreted subsystems that render the linguistic
system inherently complex in each dimension. This hybridity explains the difficulty
in constructing Butler’s macro-model, but also indicates how it might
be done. Subsystems that add complexity in one dimension are often explained
by another, e.g. sub-patterns for English plural formation arose for sociocultural
reasons (Classical borrowing); typological exception groups (e.g. Director
General) have a diachronic explanation. Thus, future modelling will benefit
from the flexibility to cross-refer between dimensions.
Life before Nation
Authors: Meara Paul
Published: April 2014

This paper presents a bibliometric analysis comparing the research on L2
vocabulary acquisition published in 1982 and 2006. A set of co-citation maps
shows that there are some significant changes in the field over this period. The
most important of these changes is a growing consensus in vocabulary research,
mainly focussed on the work of Paul Nation, whose seminal book Teaching and
Learning Vocabulary appeared in 1990. The data also suggest that the influence
of cognitive psychologists – important in the 1982 data has become much
weaker in the 2006 research. The paper argues that co-citation analysis provides
a useful tool for exploring important trends in the intellectual history of
vocabulary research.
How did we think?
Authors: Janssens Karolien , Nuyts Jan
Published: April 2014

This paper presents a diachronic corpus investigation into the Dutch mental
state predicate denken ‘think’. It investigates both the semantic development
(specifically, the evolution in the non-attitudinal vs. the attitudinal meanings of
the verb) and the grammatical development (the evolution in terms of the types
of grammatical patterns with which the verb appears), and the correlations
between the two, from Old Dutch onwards. The discussion focuses specifically
on the implications for our understanding of the processes of grammaticalisation
and subjectification, and their correlations: the verb shows clear signs of a
process of semantic subjectification, but not of structural grammaticalisation,
hence it offers evidence for the assumption that these two processes are less
intimately intertwined than is often assumed in the literature.
Nominal reference and the dynamics of discourse
Authors: Davidse Kristin
Published: April 2014

In this paper I will address what appear to be some important gaps in the
traditional approach to nominal reference as a cohesion-creating resource:
(i) ignoring of relations other than co-referentiality, such as those expressed by
quantifying determiners, (ii) neglect of the contribution made by type specifications
to the reference function; (iii) restriction of the type specifications to those
lexically predicated by the NP itself, (iv) discounting of the cumulative build-up
of information relating to referential sets and referent classification in the mind
of the reader. In the first half of the article, I survey the cognitive instructions
given by the main determiner types of NPs: definite versus indefinite identifiers,
and relative versus absolute quantifiers. In the second half of the article
I develop and illustrate an alternative analysis of discourse referents that does
take into account elements (i) to (iv).
‘Pragmatic punting’ and prosody
Authors: Romero-Trillo Jesús
Published: April 2014

The aim of this chapter is to present the notion of “pragmatic punting” as the
cognitive process that confirms that communication in interaction has achieved
its goal. The theoretical tenets of this mechanism are based on the principles
of communicative context and on the Dynamic Model of Meaning. The study
compares the prosodic patterns of pragmatic markers in the London-Lund
Corpus and in the LINDSEI Corpus (the Spanish section) in order to describe
the prototypical realization of pragmatic punting in native and non-native
English conversation respectively. The results show the disparity in the use of
pragmatic punting between both groups of speakers. The conclusions indicate
that the improvement of the non-natives’ awareness of the intonation patterns
and distribution of pragmatic markers would contribute to the improvement of
their communicative competence.
Strategies of (in)directness in Spanish speakers’ production of complaints and disagreements in English and Spanish
Authors: Hidalgo-Downing Laura , Hidalgo Downing Raquel , Downing Angela
Published: April 2014

This article presents the results of a study carried out with Spanish University
students on their use of strategies of (in)directness when expressing complaints,
disapprovals and disagreements in English and Spanish. We adopt a role-play
eliciting procedure for the collection of what a speaker thinks and what s/
he
actually says in a given situation. Our results show a tendency to mitigate the
actual words uttered with regard to the thought processes in both languages.
However, while in English students show a preference for conventional indirectness,
in Spanish there is a greater variation in the strategies employed.
Thus, mitigation, especially in Spanish, is often realised by means of the co-occurrence
of negative and positive politeness strategies across several speech
acts, thus performing complex utterances. These results point at an awareness of
students’ attempts to adapt to the model of indirectness that is assumed of the
English culture, vs. the model of directness associated to the Spanish culture.
Case and word order in Lithuanian infinitival clauses revisited
Authors: Arkadiev Peter M.
Published: April 2014

This paper considers the Lithuanian constructions with the Dative and Genitive marking of direct objects of transitive verbs in purpose infinitival clauses, studied in Franks and Lavine (2006). I adduce empirical evidence and conceptual arguments both speaking against the analysis proposed by Franks and Lavine (2006), and argue for a different account based on recent “non-orthodox” proposals in case theory. My analysis of the Lithuanian constructions is inspired by a typological comparison with Australian languages possessing “complementizing” and “associating” case marking and morphological case-stacking. I propose that the mechanism of multiple case assignment in syntax is operative in Lithuanian and show how it can naturally account for the Dative-plus-Infinitive and Genitive-plus-Infinitive constructions.
Subjecthood in specificational copular constructions in Lithuanian
Authors: Mikulskas Rolandas
Published: April 2014

Superficially, copular sentences serving specificational function, such as The winner of the race is John or The tallest girl in the class is Molly, look like inverted structures as compared with their more usual predicative counterparts, cf. John is the winner of the race and Molly is the tallest girl in the class. Though in terms of word order the specificational copular construction can be thought of as derived from its predicative counterpart by means of inversion, this inversion is strongly motivated by the communicative demands of specification and adds new structural properties to the construction: the former predicative nominal ‘moved’ into precopular position inevitably acquires an existential presupposition with regard to its unique referent, thus exhibiting role definiteness, and the information structure of the construction becomes bound to the different referential functions of its two nominals (the role defining NP is always a topic and the role specifying NP a comment). There are thus good functional and structural reasons to treat this specificational construction as a distinctive subtype of copular predication. Syntactically, however, the specificational copular construction, as compared to its predicative counterpart, remains, in many respects, a non-canonical predication. For instance, pseudoclefts (which represent a special case of the specificational copular construction), pose serious challenges to Binding Theory because of certain well-known connectivity effects. Another problem with this kind of copular predication − and this will be the topic of this article − is the inconsistency of subject assignment in such constructions across languages (and sometimes even within the same language). For example, in English, Danish, Swedish and French, the morphosyntactic marking of the subject is conferred on the first nominal of the specificational copular construction, while in Lithuanian, Russian, as well as in Italian and German, the second nominal of the construction acquires this marking. The fact that semantically equivalent structures acquire opposite patterns of morphosyntactic coding of the main grammatical relation, suggesting opposite directions of conceptualization of essentially the same specificational relation, poses a challenge to the main principle of Cognitive Grammar, the so-called content requirement. If one sticks rigorously to the morphosyntactic coding used in specificational copular sentences, one encounters difficulties with defining grammatical relations in terms of conceptual relevance, i.e., as a trajector / landmark configuration.