bluuebunny/crossref_metadata_2025 huggingface dataset:
Short communication: Algal leaf spot associated with Cephaleuros virescens 1 Ulvophyceae)
Authors: SUNPAPAO ANURAG , PITALOKA MUTIARA K. , ARIKIT SIWARET
Published: November 2015

Sunpapao A, Pitaloka MK, Arikit S. 2015. Algal leaf spot associated with Cephaleuros virescens (Trentepohliales,Â Ulvophyceae) on Nephelium lappaceum in Thailand. Biodiversitas 17: 31-35. Algal leaf spot disease of Nephelium lappaceum (rambutan)Â was observed in southern Thailand. The algae were isolated on Boldâ€™s basal medium (BBM) a nd identified based on appearance of the lesions, algal morphology and molecular properties. Characteristics of the filamentous thallus cells, sporangiophores, sporangia, gametes and zoospores were clarified. A portion of the 18S small subunit rRNA was amplified to validate the morphological identification by sequence similarity. To summarize the main results, the plant parasite causing algal leaf spot was identified as Cephaleuros virescens, and in sequencing-based phylogenetic analysis the Cephaleuros PSU-R5.1 isolate from rambutan grouped with the algae in genus Cephaleuros. This confirms C. virescens as a causal organism of algal leaf spot disease on rambutan in southern Thailand.
2-D Imaging of Concealed Objects using Circular Co-Arrays at MM Wave Frequencies: Simulation and Experimental Results
Authors: Dixit Rajendra Prasad
Published: November 2015

Simulation and experimental results at 35 GHz, for a single target of unit reflectivity, a concrete pillar and a gun shaped object placed in the central region  of 2-D scene , have been presented using circularly co-located transmit and receive co-arrays. Simulation program has been written in MATLAB to reconstruct the raw image using an improvised algorithm. Simulation and experimental results confirm the method of reconstruction of image. Reconstruction of a Gun-shaped object has also been shown with help of simulation and experimental results. Reconstruction of image has been performed using post data acquisition processing on the received scattered data. Experimental results confirm that the method can be used to reconstruct quality image for detection of concealed metallic objects using MM wave frequencies.
Enhanced Singular Value Decomposition based Fusion for Super Resolution Image Reconstruction
Authors: Sundar K. Joseph Abraham , Vaithiyanathan V. , Manickavasagam M. , Sarkar A.K.
Published: November 2015

The singular value decomposition (SVD) plays a very important role in the field of image processing for applications such as feature extraction, image compression, etc. The main objective is to enhance the resolution of the image based on Singular Value Decomposition. The original image and the subsequent sub-pixel shifted image, subjected to image registration is transferred to SVD domain. An enhanced method of choosing the singular values from the SVD domain images to reconstruct a high resolution image using fusion techniques is proposesed. This technique is called as enhanced SVD based fusion. Significant improvement in the performance is observed by applying enhanced SVD method preceding the various interpolation methods which are incorporated. The technique has high advantage and computationally fast which is most needed for satellite imaging, high definition television broadcasting, medical imaging diagnosis, military surveillance, remote sensing etc.
Unmanned Aerial Vehicle Domain: Areas of Research
Authors: Demir Kadir Alpaslan , Cicibas Halil , Arica Nafiz
Published: November 2015

Unmanned aerial vehicles (UAVs) domain has seen rapid developments in recent years. As the number of UAVs increases and as the missions involving UAVs vary, new research issues surface. An overview of the existing research areas in the UAV domain has been presented including the nature of the work categorised under different groups. These research areas are divided into two main streams: Technological and operational research areas. The research areas in technology are divided into onboard and ground technologies. The research areas in operations are divided into organization level, brigade level, user level, standards and certifications, regulations and legal, moral, and ethical issues. This overview is intended to serve as a starting point for fellow researchers new to the domain, to help researchers in positioning their research, identifying related research areas, and focusing on the right issues.

Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 319-329, DOI: http://dx.doi.org/10.14429/dsj.65.8631
Mechanical and Wear Properties of SiC/Graphite Reinforced Al359 Alloy-based Metal Matrix Composite
Authors: Bansal Shubhranshu , Saini J. S.
Published: November 2015

Al359 alloy was reinforced with Silicon Carbide and Silicon Carbide/Graphite particles using stir casting process. Thereafter their mechanical and wear properties were investigated. It was found that the hardness of the Al359-Silicon Carbide composite is better than Al359-Silicon Carbide-Graphite composite. The Silicon Carbide/Graphite reinforced composite exhibits a superior ultimate tensile strength against Silicon Carbide reinforced composite. The wear test was conducted at different loading, sliding velocities and sliding distances conditions. Results showed that the wear resistance of Al359 alloy increased with the reinforcement of Silicon Carbide/Graphite material for higher loading, sliding velocities and sliding distance conditions. SEM images of the worn surface of the pin were examined to study their wear mechanism.

Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 330-338, DOI: http://dx.doi.org/10.14429/dsj.65.8676
Numerical Study of Pulse Detonation Engine with One-step Overall Reaction Model
Authors: Srihari P. , Mallesh M.A. , Prasad G. Sai Krishna , Charyulu B.V.N. , Reddy D.N.
Published: November 2015

This paper presents an insight for the study of transient, compressible, intermittent pulsed detonation engine with one-step overall reaction model to reduce the computational complexity in detonation simulations. Investigations are done on flow field conditions developing inside the tube with the usage of irreversible one-step chemical reactions for detonations. In the present simulations 1-D and 2-D axisymmetric tubes are considered for the investigation. The flow conditions inside the detonation tube are estimated as a function of time and distance. Studies are also performed with different grid sizes which influence the prediction of Von-Neumann spike, CJ Pressure and detonation velocity. The simulation result from the single-cycle reaction model agrees well with the previous published literature of multi-step reaction models. The present studies shows that one-step overall reaction model is sufficient to predict the flow properties with reasonable accuracy. Finally, the results from the present study were compared and validated using NASA CEA.

Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 265-271, DOI: http://dx.doi.org/10.14429/dsj.65.8730
Interference Aware Optimisation of Throughput in Cognitive Radio System
Authors: Verma Gaurav , Sahu O.P.
Published: November 2015

In the cognitive radio (CR) system where spectrum sensing and data transmissions are performed simultaneously, the proper selection of frame duration (τ) is of utmost importance. Small τ leads to an increased false alarm probability while large value of it delays implementation of sensing decision of the current frame to the next. The former case decreases the achievable throughput of the CR user while latter one may disturb the licensed user communication. Under the constraints of maintaining a target detection probability of dP, this paper attempts to design a frame duration τ where achieved throughput of the CR system is maximised. To do so, an analysis of achievable throughput with τ was performed which reveals that, initially, with the increase in τ, the achievable throughput increases sharply, but after its certain value, the increments are negligible and achievable throughput appears to maintain a constant value. The performed analysis shows that, it is not possible to perfectly optimize τ, however, a close optimisation can still be performed which can maximise the achievable throughput. From the realistic point of view, the CR system is further modelled under uncertain noise conditions. The achieved simulation results well justify the presented analysis.

Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 312-318, DOI: http://dx.doi.org/10.14429/dsj.65.8739
Microstructure and Mechanical Properties of Laser Beam Welds of 15CDV6 Steel
Authors: Ramesh M.V.L , Rao P. Srinivasa , Rao V. Venkateswara
Published: November 2015

The present study is concerned with laser beam welding of 15CDV6 steel, that is in the hardened (quenched and tempered) condition before welding. Autogenously butt-welded joints are made using carbon dioxide laser with a maximum output of 3.5 kw in the continuous wave mode. Weld microstructure, microhardness measurement across the weldment, transverse tensile properties, and room temperature impact properties of the weldment have been evaluated. The fusion zone exhibits a epitaxial grain growth. The microstrutural features of heat-affected zone and fusion zone vary, due to different thermal cycles for which these were subjected during welding. The average weld metal hardness was 480 Hv. The observed hardness distribution across the welds were correlated with the microstructures. The welds exhibited lower toughness of 50 joules as compared to parent metal of 55 joules and the tensile strength values of the welded specimens are close to that obtained for sheet specimens.

Defence Science Journal, Vol. 65, No. 4, July 2015, pp. 339-342, DOI: http://dx.doi.org/10.14429/dsj.65.8749
Human Cognition and Emotion using Physio Psychological Approach : A Survey
Authors: Amutha B. , Kurian Bobin , Nanmaran, Karthick , Parvathi N. , Sivagami G. , Balasubramanian M.
Published: November 2015

A soldier’s responsibility in the military includes his physical and mental attitudes which makes him to support the army in a full-fledged manner. This type of human dimension recognizes Soldier readiness from training proficiency to motivation for the Army’s future success. It introduces the concept of holistic fitness, a comprehensive combination of the whole person, including all components of the human dimension as a triad of moral, cognitive and physical components. The human dimension concept is directly related to the human mind and memory system. In this research, a system which will be capable of recognizing human emotions based on physiological parameters of a human body is discussed. The data from the system is fed to a computer where it is stored. Stored information regarding human parameters is retrieved and classified using support vector machine to generate a data set about the various emotions the human poses at a specific situation. The emotion, thus calculated is grouped to generate a grade for his present status. This grade is used to recommend the suitable working environment for the person.
The end of art as a capitalist discourse
Kapitalist bir söylem olarak sanatın sonu
Authors: Samsun Meysem
Published: November 2015

In the present paper, the claim, art or painting is going through its end, is evaluated as a capitalist discourse; and some related samples were analyzed in terms of how they were passivized and become dysfunctional by the capitalist system. French thinker Jean Baudrillard is the most effective and distinguished sample of the claim, the end of art. In this point, after evaluating Danto’s ideas from the modern perspective, the claim of “end of art” will be discussed through Baudrillard’s post-modern perspective. When Baudrillard directed his gaze onto the world of art, the situation he saw was not a very optimistic one. Modern art and post-modern art, in which the thinker is also included, is the production of the Western World. As a result, in this sense, the literature of art is merely valid for the modern art taking its roots from the Western World and this domain of thinking. According to Baudrillard, art has lost its own privilege and purpose; it is not made for development of culture, but for consumption of this culture; and instead of existing through its own content of meaning, it has been unconsciously spread over all segments of the society. As a result, the discussion of what is art and what is not has progressively become more ambiguous.

 

Özet

Bu çalışmada sanatın ya da resmin sonunun geldiği savı kapitalist bir söylem olarak değerlendirilmiş, sanatın kapitalist sistem tarafından nasıl edilgen ve işlevsiz kılındığına ilişkin örneklendirmelerle işlenmiştir. Sanatın sonu sav’ının, bu örneklendirme ile, en etkili duayen ismi Fransız düşünür Jean Baudrillard’dır. Burada, modern anlamda Danto’nun görüşlerine yer verildikten sonra ‘’sanatın sonu’’ savı, postmodern anlamda, Baudrillard üzerinden tartışılacaktır. Baudrillard bakışını sanat dünyasına çevirdiğinde gördüğü manzara iç açıcı değildir. Burada bahsedilen çağdaş sanat, postmodern sanat, düşünürün de içinde bulunduğu Batı dünyasının üretimidir. Dolayısıyla, bu bağlamda literatür, sadece Batı dünyası ve bu düşünce dünyasından beslenen çağdaş sanat için geçerlidir. Baudrillard’a göre sanat artık sahip olduğu ayrıcalığı ve amacını yitirmiş, kültürü geliştirmek için değil, tüketilmek için yapılmış ve kendi anlam içeriği ile var olmak yerine toplumun tüm katmanlarına bilinçsizce yaydırılmış ve neyin sanat olup neyin sanat olmadığı tartışmaları iyice bulanıklaşmıştır.
Selecting laser eye protectors – a helping hand
Authors: Gappenach Catherine , Krüger Jörg , Offenhäuser Friedrich , Pintaske Sabine , Krauß Hans-Joachim
Published: November 2015

The European laser safety standards EN 207, EN 208, and EN 12254 each contain an annex B, which serves as a guidance for the selection of products. These annexes are informative only and are therefore not binding. As there are a variety of hazard scenarios, it is not recommended to change these annexes to a normative status, through which they would become mandatory. Instead, it is recommended to allow users to apply their own skills and know-how in selecting appropriate products, justifying where and why they deviate from the guidance in the standards. This paper explains the background on which the guidance for selection in the annexes of the standards is based and shows physically meaningful leeway.
Transformation of Phenolic Compounds by Fe(III) in the Aqueous Solution in Dark and Under Irradiation
Authors: Belattar S. , Debbache N. , Seraghni N. , Sehili T.
Published: November 2015

The degradation of phenolic compounds (PC) by Fe(III) aquacomplexes was investigated in homogeneous phase at neutral pH in dark and using monochromatic irradiation lamp (365 nm). The process of degradation depends essentially on the concentration of monomeric species, which is the most reactive species in terms of HO• radicals formation. A dark study of a system containing a mixture of phenolic compounds (3,5-dimethylphenol, 2,6-dimethylphenol, m-methylphenol, phenol) and Fe(III) was performed before starting the photochemical study. In this step only the 2,6-dimethylphenol give a thermal reaction with iron in homogenous solution. Under monochromatic excitation (365 nm), the photodegradation of PC induced by Fe(III) aquacomplexes showed that this process followed pseudo first-order kinetic. We investigate also the effect of initial concentrations of Fe(OH)2+, Fe(III) and the substrate. Tertiobutanol, used as scavenger of (HO•), confirmed that this radical was the main pathway of PC degradation. However the degradation of the 2,6-dimethylphenol in the presence of tertiobutanol, was not slowed completely which confirm that the degradation was a combination of thermal and photochemical reactions.
Homology cluster differential expression analysis for interspecies mRNA-Seq experiments
Authors: Gelfond Jonathan A. , Ibrahim Joseph G. , Chen Ming-Hui , Sun Wei , Lewis Kaitlyn , Kinahan Sean , Hibbs Matthew , Buffenstein Rochelle
Published: November 2015

There is an increasing demand for exploration of the transcriptomes of multiple species with extraordinary traits such as the naked-mole rat (NMR). The NMR is remarkable because of its longevity and resistance to developing cancer. It is of scientific interest to understand the molecular mechanisms that impart these traits, and RNA-sequencing experiments with comparator species can correlate transcriptome dynamics with these phenotypes. Comparing transcriptome differences requires a homology mapping of each transcript in one species to transcript(s) within the other. Such mappings are necessary, especially if one species does not have well-annotated genome available. Current approaches for this type of analysis typically identify the best match for each transcript, but the best match analysis ignores the inherent risks of mismatch when there are multiple candidate transcripts with similar homology scores. We present a method that treats the set of homologs from a novel species as a cluster corresponding to a single gene in the reference species, and we compare the cluster-based approach to a conventional best-match analysis in both simulated data and a case study with NMR and mouse tissues. We demonstrate that the cluster-based approach has superior power to detect differential expression.
Optische Qualitätsprüfung von Batterieseparatoren
Authors: Huber Josef , Tammer Christoph , Kempter Adrian , Seidel Christian , Reinhart Gunther
Published: November 2015

Die Anforderungen an die Sicherheit von Lithium-Ionen-Zellen
rücken durch deren Einsatz in Elektrofahrzeugen zunehmend in den
Vordergrund. Als Basis für die Zellsicherheit müssen typische
Produktionsfehler in Batterieseparatoren zuverlässig erkannt
werden. Die Bildverarbeitung stellt hierfür eine geeignete Methode
dar. Nachfolgend wird ein System zur Qualitätskontrolle
beschrieben, das eine Detektion dieser Fehler ermöglicht. Die
Besonderheit ist dabei die Unterscheidung auftretender Defektarten
untereinander und die Abgrenzung von nicht qualitätsrelevanten
optischen Effekten mittels eines expertenbasierten Ansatzes zur
Fehlerklassifikation.
Does Dutch a-scrambling involve movement? Evidence from antecedent priming
Authors: van de Koot Hans , Silva Renita , Felser Claudia , Sato Mikako
Published: November 2015

The present study focuses on A-scrambling in Dutch, a local word-order alternation that typically signals the discourse-anaphoric status of the scrambled constituent. We use cross-modal priming to investigate whether an A-scrambled direct object gives rise to antecedent reactivation effects in the position where a movement theory would postulate a trace. Our results indicate that this is not the case, thereby providing support for a base-generation analysis of A-scrambling in Dutch.
Ex Concordia Discors
Authors: Sherr Richard
Published: November 2015

In March 1558 Pope Paul IV ordered his College of Singers to consider two Spanish sopranos, then in Naples. Called to Rome for an audition, they were accepted according to the normal procedure (a vote). Two Italian members, however, aggressively abstained from participating. For this they would have been severely punished without they avoided through the intervention of their patron, the papal nephew Cardinal Carlo Carafa. In 1559 Paul IV demanded that the abstainers be dismissed, but their colleagues persuaded him to allow them to remain. Also in 1559 three other papal singers suffered when Cardinal Carafa was disgraced and banished by Paul IV. In 1562 the most recalcitrant singer in the original affair resigned from the choir for reasons that defy explanation. Though minor in itself, this curious tempest in a teapot opens a window into larger issues concerning the power relationship of popes and cardinals to the papal singers and shows the real dangers that could ensue from being a member of the household of a cardinal. Moreover, it exposes national tensions within the choir, shows the singers caught up in the political repercussions of the last spasms of the short and disastrous pontificate of Paul IV, and even gives a glimpse into their possibly aberrant personalities. Cardinal Carlo Carafa is also shown to have had a serious interest in the papal choir and individual papal singers for reasons that have yet to be elucidated and may not have been entirely musical.
Nominals with the suffix -ač in Croatian
Authors: Birtić Matea Andrea
Published: November 2015

The paper presents an analysis of Croatian agentive nominals with the suffix -ač within the Distributed Morphology approach, adopting and applying Alexiadou & Schäfer’s (2010) model. The internal morphological structure of the -ač nouns, and their eventive properties were considered in detail. The analysis has shown that the eventive/non-eventive properties of -ač nouns do not depend on animacy, but rather on the episodic vs. dispositional distinction. However, instrument nominals are distinguished from animate nominals in some respects. Croatian -ač nouns exhibit properties that cannot be completely captured by the framework adopted.
What are you afraid of? The construction of meaning in X-(o)phobie lexemes
Authors: Lasserre Marine
Published: November 2015

French neoclassical compounds X-(o)phobie display two distinct meanings : ‘fear’ and ‘hostility’. In order to determine which meaning is involved in a given complex word, X-(o)phobie lexemes are studied according to the contexts they are used in. In fact, in a non-compositional analysis, complex words cannot be studied in isolation since they construct their meaning whenever they are employed. The distributional hypothesis offers a new way to examine the semantics of complex words. Two methods make it possible to investigate the variation of meanings in X-(o)phobie lexemes. Moreover, the use of Google data enables an analysis of the construction of neologisms meaning.
Effect of triticale grain characteristics, scouring, and extrusion conditions on physico-chemical properties, antioxidant activity, and volatile compounds of flat bread
Authors: Obuchowski W. , Makowska A. , Mildner-Szkudlarz S. , Szwengiel A. , Majcher M. , Remiszewski M.
Published: November 2015

The objective of the study was to determine the effect of grain preparation technology, extrusion cooking conditions, and triticale cultivars on physico-chemical properties of crisp bread. Triticale cultivars used in the experiments differed in protein content, starch content, amylolytic activity, and viscosimetric properties. The type of the twinscrew extruder used has an effect on starch degradation, phenolic contents, and antioxidant activity of the product, but a greater effect on those characteristics is found for grain scouring prior to extrusion. All factors had an effect on volatile compound amounts in crisp bread, but the direction and range of these changes were random in character. Results of this study show that triticale grain can be useful raw material for the production of flat bread.
Reduction of microorganisms in marinated poultry breast using oregano essential oil and power ultrasound
Authors: Piñon M.I. , Alarcon-Rojo A.D. , Renteria A.L. , Mendez G. , Janacua-Vidales H.
Published: November 2015

Marinated chicken meat is an ideal substrate for the growth of microorganisms. The aim of this study was to determine the effect of high-intensity ultrasound on the microbial flora of chicken meat marinated in oregano oil. Three concentrations of oregano oil (0%, 0.1%, and 0.3%) and two types of marination (traditional and highintensity ultrasound) were tested. Microorganisms were enumerated immediately after marination and on 7, 14, and 21 days of chilled storage. Marination in oregano oil resulted in significant differences (P<0.05) in the numbers of anaerobic, lactic acid bacteria, and mesophiles. Ultrasound with 0.1% OEO did not show any effect on the three types of bacteria. The treatment with 0.3% oregano oil and ultrasound had the greatest effect on controlling microbial growth. Therefore, a combination of ultrasound and oregano oil is the most appropriate option for reducing the growth of mesophilic, anaerobic, and lactic acid bacteria in vacuum-packed marinated chicken breasts during chilled storage.
Hydrolysis of casein and β-lactoglobulin by immobilized papain after pre-treatment with immobilized trypsin
Authors: Pessato T.B. , Tavano O.L.
Published: November 2015

Protein hydrolysis using immobilized proteases may present problems, which are mainly caused by the diffusion of macromolecular substrate. Pre-hydrolysed substrate could be a viable alternative in this process. The aim of this work was to test the casein and β-lactoglobulin hydrolysis using immobilized papain on glyoxyl-agarose, following substrate pre-treatment with immobilized trypsin. Although immobilized papain showed difficulties to degrade the milk proteins, after 10 min of trypsin pre-hydrolysis, the immobilized papain was able to achieve the maximum degree of hydrolysis in shorter time. For pre-hydrolysate casein, the immobilized papain reached 98.9% at 60 min total reaction (including the 10 min pre-digestion). As for β-lactoglobulin, immobilized papain was capable of achieving maximum levels after just 60 min of reaction, where the free enzyme only achieved 60% of its maximum. Pre-hydrolysis with trypsin appears to have worked well as a pre-treatment method to increase the proteolytic action of immobilized papain.
Effect of short-term storage on walnut fruit quality
Authors: Kónya É. , Bujdosó G. , Berki M. , Nagy-Gasztonyi M. , Adányi N.
Published: November 2015

Two Hungarian and two introduced walnut cultivars were examined as fresh samples and under storage. Some important compositional data were determined in order to evaluate the differences between the cultivars and the changes after storage. The cultivars’ oil contents were the same, but there was some difference in fatty acid composition; ‘Alsószentiváni 117’ had a higher mono-unsaturated fatty acid content than the others. Considering the oxidative stability, ‘Alsószentiváni 117’ contained good properties in all stages (induction time equals or higher than 10 h). Lower antioxidant capacity was measured in ‘Chandler’ samples compared to the others. ‘Alsószentiváni 117’ has higher α- and γ-tocopherol contents than the other cultivars studied. Two different drying methods were also compared in case of the Hungarian cultivars. The changes in compositional data showed no tendencies. We found that Hungarian cultivars were at least as valuable as the introduced ones.
Enhanced Security Protocol in Wireless Sensor Networks
Authors: Aseri Trilok C. , Singla Neha
Published: November 2015

The need for security in communications is in fact not new. This need has existed in military communications for thousands of years. In this paper, we focus on network protocols that provide security services. Wireless sensor network is an emerging technology that shows applications both for public as well as military purposes. Monitoring is one of the main applications. A large amount of redundant data is generated by sensor nodes. This paper compares all the protocols which are designed for security of wireless sensor network on the basis of security services and propose an improved protocol that reduces communication overhead by removing data redundancy from the network. By using the message sequence number we can check whether it is old message or new message. If the message is old then no need to send that message thereby reducing overhead. It also integrates security by data freshness in the protocol.
Investigating hydraulic fracture at a puddle clay core dam
Authors: Tedd Paul , Carter Ian C. , Watts Ken S. , Charles J. Andrew
Published: November 2015

More than 20 years after the construction of Greenbooth dam, internal erosion of the puddle clay core close to the abutments led to localised settlement. Following remedial grouting, the dam appears to have behaved satisfactorily with relatively little settlement of the crest. No comparable problem has occurred in the central section of the dam, confirming that the steep abutments were a major factor in the internal erosion incident. However, in 2001 a borehole investigation to evaluate seismic stability revealed a connection between the reservoir and a borehole in the middle of the core. As a consequence of this finding, investigations have been carried out to assess the vulnerability of the puddle clay core in the central section of the dam to hydraulic fracture, which is often cited as a mechanism that leads to leakage and internal erosion in clay cores of embankment dams. Earth pressure cells were installed in the core and subsequently critical pressure tests were performed in standpipe piezometers. Laboratory tests have been carried out to assess the erodibility of the puddle clay and the filter properties of the downstream fill. The results of the investigations are presented and the limitations and advantages of the various forms of field and laboratory testing are compared.
Meeting report: ICOLD 2011, Lucerne, Switzerland
Authors: Ariey Martin , Bridle Rod , Cambridge Mike , Hughes Andy , Sawyer John , Spasic-Gril Ljiljana , Williamson Tracey
Published: November 2015

The 79th annual meeting of the International Committee on Large Dams (ICOLD) was held in the Swiss city of Lucerne between 30 May and 3 June 2011. There was a good attendance of British Dam Society (BDS) members at the meetings with a total of ten delegates who represent the UK on a number of the different technical committees. In total there were more than 1000 delegates representing 65 countries.
Production of ‘green’ concrete using red gypsum and waste
Authors: Hughes P. N. , Glendinning S. , Manning D. A. C. , Noble B. C.
Published: November 2015

The main cost incurred in the production of concrete paving blocks is the cost of the cement-based binders. In addition, there is the environmental cost of quarrying and processing of these primary materials. Gypsum-based industrial by-products have been identified as alternative sources of cement. These materials have little or no production cost and their reuse negates the need for disposal, offering a more sustainable material for the production of paving blocks. Laboratory trials have investigated the properties of red gypsum, derived as a coproduct associated with titanium dioxide manufacture, mixed with pulverised-fuel ash, ground granulated blastfurnace slag, lime and basic steel slag. An assessment of samples was made using unconfined compressive strength after 28 days curing. It was found that a red gypsum ground granulated blastfurnace slag mix achieved the highest unconfined compressive strength (up to 39 MPa) and was selected for further investigation. Two binders, composed primarily of red gypsum and ground granulated blastfurnace slag, were mixed with sand and pea gravel to make 100 mm concrete cubes and compared with Portland cement for uniaxial compressive strength, stiffness and workability. The red gypsum-based binder compared favourably with Portland cement, indicating that there is potential to integrate red gypsum into concrete block mixes.
Protecting roller-compacted concrete armored emergency spillway against uplift with geocomposite drain: Loxahatchee Reservoir example
Authors: Özer A.T. , Bromwell L.G.
Published: November 2015

ABSTRACT: When designing a roller-compacted concrete (RCC) spillway for a reservoir, seepage-induced uplift pressures need to be considered. This case study describes the design, construction and post-construction performance of a drainage system consisting of a geocomposite drain immediately beneath a stair-stepped RCC spillway at the Loxahatchee Reservoir in western Palm Beach County, Florida, USA. The installation comprised 2.8 km of RCC and a geocomposite drain to construct the fixed-weir emergency spillway. The primary stability issue for the spillway was the development of excessive pore water pressure beneath the RCC in the event of rapid drawdown of the reservoir. Transient seepage analysis predicted that installation of the geocomposite drain would eliminate excess pore pressures beneath the RCC, and dramatically increase the factor of safety against uplift (increased from 0.5 to a value of the order of 6), preventing structural instability of the spillway. Since placing the reservoir in operation, no structural instability has been observed in the spillway. Also, the absence of excess pore pressure is predicted by post-construction transient seepage analysis using reservoir operational-stage data.
Numerical modelling of landfill lining system–waste interaction: implications of parameter variability
Authors: Sia A.H.I. , Dixon N.
Published: November 2015

ABSTRACT: Numerical modelling techniques can be used to examine the serviceability limit states of landfill side-slope lining systems in response to waste placement. A study has been conducted in which the variability of significant model input parameters have been investigated within a probabilistic framework using Monte Carlo simulation. Key model parameters are treated as random variables, and the statistical information required to describe their distributions has been derived from a laboratory repeatability testing programme, a literature survey and an expert consultation process. Model outputs include relative shear displacements between lining components, and tensile strains in the geosynthetic layers that occur in response to staged placement of waste against the side slope. It was found that analyses including input parameter variability were able to identify mechanisms influencing liner performance and their probability of occurrence. These mechanisms include large (i.e. ≫100 mm) relative displacements at interfaces that can generate post-peak strengths, and mobilised tensile strains in the geomembrane and geotextile layers. Additionally, it was found that relative displacements at the controlling (i.e. weakest) liner interface are greater for landfills with a steep side slope, for stiffer waste and thicker waste lifts, while tensile strains in the geosynthetic elements are greater for steep side slopes, more compressible waste and thinner waste lifts. Outputs from probabilistic analyses such as that used in this study can guide engineers regarding geometries and materials that could produce waste-settlement-generated serviceability limit state failures, and hence can be used to support more reliable designs.
Numerical analysis of centrally and eccentrically loaded strip footing on geotextile-reinforced sand
Authors: Şadoğlu E.
Published: November 2015

ABSTRACT: Geosynthetics have been proposed for use as a method of increasing the bearing capacity of a soil medium below a footing, and of reducing settlement. In this study, load-settlement behaviour of strip footings was investigated experimentally and numerically. The ultimate load of centrally and eccentrically loaded model strip footings resting on reinforced and unreinforced sand were determined under plane strain conditions. Sand was placed in a tank at a relative density of 0.74 to obtain general shear failure. Numerical simulation of the experimental set-up was carried out using Plaxis 2D software. Woven geotextile was used as the soil reinforcement. The Mohr–Coulomb material model was utilised to model the sand and load–settlement curves were obtained numerically. Using the reinforcement caused an increase in ultimate load in both numerical simulations and laboratory tests. The effect of changes in ultimate bearing capacity due to load eccentricity was investigated using both numerical and analytical methods.
Seismic reliability assessment of internal stability of reinforced soil walls using the pseudo-dynamic method
Authors: Basha B.M. , Babu G.L.S.
Published: November 2015

ABSTRACT: The study focuses on probabilistic assessment of the internal seismic stability of reinforced soil structures (RSS) subjected to earthquake loading in the framework of the pseudo-dynamic method. In the literature, the pseudo-static approach has been used to compute reliability indices against the tension and pullout failure modes, and the real dynamic nature of earthquake accelerations cannot be considered. The work presented in this paper makes use of the horizontal and vertical sinusoidal accelerations, amplification of vibrations, shear wave and primary wave velocities and time period. This approach is applied to quantify the influence of the backfill properties, geosynthetic reinforcement and characteristics of earthquake ground motions on reliability indices in relation to the tension and pullout failure modes. Seismic reliability indices at different levels of geosynthetic layers are determined for different magnitudes of seismic acceleration, soil amplification, shear wave and primary wave velocities. The results are compared with the pseudo-static method, and the significance of the present methodology for designing reinforced soil structures is discussed.
Creep behavior of geosynthetics using confined-accelerated tests
Authors: França F.A.N. , Bueno B.S.
Published: November 2015

ABSTRACT: The creep behavior of geosynthetics has commonly been determined using standardized creep tests, which are time consuming and very expensive. In addition, these tests involve the use of in-isolation specimens. Thus they are not likely to consider the overall effect of soil confinement. Confined creep tests conducted at elevated temperature can be used to address these negative aspects of standardized creep tests. This paper presents a pioneering laboratory apparatus developed in order to conduct confined, accelerated and confined-accelerated creep tests. In addition, preliminary tests were performed to assess the new equipment's capability of conducting confined and accelerated creep tests. These tests were performed using a biaxial geogrid, a woven geotextile, and a nonwoven geotextile. The new equipment allowed different conditions to be reproduced. The creep behavior of the nonwoven geotextile and the geogrid was found to be very sensitive to soil confinement. On the other hand, the woven geotextile presented a creep behavior independent of soil confinement. The geogrid results did not agree with reports in the technical literature. Accordingly, these results showed the importance of characterizing the effect of soil confinement in geosynthetics creep behavior. Additionally, these preliminary results showed the potential of the new device to overcome the main negative aspects of standardized creep tests on geosynthetics.
Influence of randomly distributed geofibers on the integrity of clay-based landfill covers: a centrifuge study
Authors: Viswanadham B.V.S. , Rajesh S. , Divya P.V. , Gourc J.P.
Published: November 2015

ABSTRACT: The main objective of this paper is to examine the influence of discrete and randomly distributed geofiber reinforcement on the integrity of clay-based landfill covers subjected to differential settlements in a geotechnical centrifuge. A series of centrifuge tests was performed on model clay-based landfill covers with and without geofiber reinforcement at 40 gravities. A hydraulic-based differential settlement simulator was used to induce continuous differential settlements with a distortion level up to 0.125. The type and moist-compacted conditions of the soil barrier and fiber content were held constant, and the thickness of the soil barrier and the fiber type are varied. The performance of the soil barrier with and without geofiber reinforcement having an overburden pressure equivalent to that of landfill covers was monitored by measuring water breakthrough at the onset of differential settlement. With an increase in the thickness of the geofiber-reinforced soil barrier, and with the provision of an overburden equivalent to that of landfill cover, the integrity of the geofiber-reinforced soil barrier was found to be retained, even after inducing a distortion level of 0.125. Analysis and interpretation of the test results indicate the significant potential for geofiber reinforcement to decrease and to retard soil crack potential in a discrete and randomly distributed soil barrier reinforced with geofibers, while retaining its hydraulic performance.
Numerical modelling of thermally induced desiccation of geosynthetic clay liners observed in laboratory experiments
Authors: Southen J.M. , Rowe R.K.
Published: November 2015

ABSTRACT: A fully coupled model is used to simulate the results of large-scale laboratory tests that investigated the non-isothermal behaviour of geosynthetic clay liners in landfill basal liner applications. Results of numerical simulations of the laboratory tests in terms of water content, capillary pressure, temperature and stress distributions are presented, and encouraging agreement between the numerical and experimental results is achieved. Under the conditions examined, a 25°C/m temperature gradient led to the development of tensile stresses within the GCL, increasing the resultant likelihood of cracking. A Poisson's ratio of 0.25 resulted in predicted horizontal tensile stresses supporting qualitative observation of desiccation cracking in the GCLs. One important implication of the work reported herein is that elevated temperatures need not occur for extended periods to create the risk of desiccation.
Reliability-based design of spread foundations by Monte Carlo simulations
Authors: WANG Y.
Published: November 2015

In this paper a general reliability-based design (RBD) approach for spread foundations is developed that addresses, explicitly and simultaneously, the ultimate limit state (ULS), serviceability limit state (SLS), reliability and economic requirements. The design process is formulated as an expanded reliability problem that is evaluated by a single run of Monte Carlo simulations (MCS). Design parameters (i.e. foundation width B, length L and depth D) are artificially treated as discrete uniform random variables, and the design process is considered as a process of finding failure probabilities for designs with various combinations of B, L and D (i.e. conditional probability p(Failure|B,L,D)) and comparing them with target probability of failure pT. Feasible designs are those with p(Failure|B,L,D) ≤ pT, and the feasible design with the minimum construction cost is selected as the final design. Equations are derived for this expanded reliability-based design (RBDE) approach and criteria are established for the minimum number of MCS samples to ensure a desired level of accuracy. The RBDE approach with MCS is illustrated through a design example of a square spread foundation with a fixed depth that has been used for the evaluation of Eurocode 7. The results are consistent with those from previous reliability analysis reported in the literature. In addition, the RBDE approach with MCS offers design engineers insights into how the expected performance level of spread foundations changes as B, L and D change, and it allows design engineers to adjust pT, without additional computational efforts, to cater for the needs of particular projects. It also provides design engineers with flexibility in modelling the uncertainties and selecting proper deterministic ULS and SLS calculation models.
On the relative merits of simple and advanced constitutive models in dynamic analysis of tunnels
Authors: KONTOE S. , ZDRAVKOVIC L. , POTTS D.M. , MENKITI C.O.
Published: November 2015

This paper compares simple constitutive models that are widely used in engineering practice with more sophisticated methods in the context of a case study. In particular, four constitutive modelling approaches have been considered: a simple elasto-plastic constitutive model (modified Cam-clay), with and without Rayleigh damping; the same model coupled with a cyclic non-linear model that can simulate pre-yield hysteresis; and finally an advanced kinematic hardening model, which is an improved version of the Al-Tabbaa & Wood two-surface model. These four approaches are used to analyse the seismic response of a section of the Bolu tunnels during the 1999 Duzce earthquake. To shed light on the performance of the constitutive models, simple site response finite-element analyses were first undertaken for the studied site, paying particular attention to the calibration of the Rayleigh damping parameters. The results of these analyses, in terms of maximum shear strain, were then used as input to an analytical elastic method (extended Hoeg method) for calculating the thrust and bending moment acting in the tunnel lining. Finally the results of dynamic time domain plane-strain analyses, employing the four adopted constitutive modelling approaches, are compared against field observations and results obtained by the extended Hoeg method, to investigate the ability of the models, of ranging complexity, to mimic soil response under seismic excitation.
Centrifuge modelling of injection near tunnel lining
Authors: Lee S. W. , Bolton M. D. , Mair R. J. , Hagiwara T. , Soga K. , Dasari G. R.
Published: November 2015

Centrifuge modelling was carried out to simulate the effect of compensation grouting on segmental tunnel lining and ground surface movement in dry sand. Two types of injection were investigated, namely strip injection and multi-point simultaneous injection. For strip injection, the investigated parameters are injection depth, injection distance to tunnel crown (separation), and injection width. The surface heave and lining deformation are found to follow the ratios of injection depth/injection width, and separation/injection width, respectively. To predict the ultimate uplift resistance of soil, two failure mechanisms are proposed for dense and loose sand conditions. In addition, a simple grout pressure transfer mechanism is also suggested to clarify the relationship between the maximum lining deformation and the parameters investigated. The multi-point simultaneous injection tests were conducted to investigate the effect of distributing the injection area. It was found that the sparseness of the injection points has brought beneficial effect to the surface heave and to the lining deformation. In all tests, dense sand shows dilation while loose sand undergoes compression as injected volume increases.
Centrifuge modelling of drained behaviour for pipelines shallowly embedded in calcareous sand
Authors: Zhang Jianguo , Stewart Douglas P. , Randolph Mark F.
Published: November 2015

Pipeline load-displacement response to monotonic and cyclic loading is an important issue in offshore pipeline engineering, especially as such response governs the on-bottom stability of unburied pipelines. The drained response is a fundamental consideration in developing a plasticity model for pipeline-soil interaction. Centrifuge model tests were conducted to investigate the drained monotonic and cyclic behaviour of offshore pipelines shallowly embedded in calcareous sand. Typical results from the tests are presented. The test data reveal a linear load-displacement response during monotonic penetration, a parabolic yield surface under combined vertical and horizontal loading, and a significant increase in stiffness and capacity after cyclic loading.
Scaling laws for centrifuge modelling of soil transport by turbulent fluid flows
Authors: Dong P. , Newson T. A. , Davies M. C. R. , Davies P. A.
Published: November 2015

The interaction between turbulent fluid flow and soil particles in local erosion processes is relevant to a number of problems in geotechnical engineering. Physical modelling of these problems at elevated gravities in a centrifuge can increase our understanding of these complex processes and provide validation and calibration for numerical analyses. The correct reproduction of the prototype behaviour requires the scale model to be constructed according to the appropriate scaling laws. Traditionally, the transport behaviour of soil particles has been studied in hydraulic laboratory models, with little consideration of the soil body and the effect it has on the observed transport. In this paper the scaling laws required for studying dynamic behaviour of soil particles associated with fluid motions using the technique of centrifuge modelling have been considered using particle mobility conditions and relative fall velocity criterion. The viability of modelling problems that involve both fluid dynamics and geotechnical processes is discussed. The study indicates that combined sediment transport and subsoil processes can be modelled using centrifugation subject to a number of limitations.