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• Japanese encephalitis (JE) is largely preventable through vaccination. • Several JE vaccines prequalified by World Health Organization are available. • Hospital-based surveillance were conducted in Bangladesh to describe JE epidemiology. • JE cases were identified each year, among all age groups, and from a widespread geographical area. • Routine childhood immunization program or mass vaccination need to be examined. Japanese encephalitis (JE) virus is recognized as a major cause of encephalitis in Bangladesh. The World Health Organization (WHO) recommends human immunization as the most effective means to control JE. Several WHO-prequalified vaccines are available to prevent JE but no vaccination program has been implemented in Bangladesh. We conducted hospital-based surveillance for acute meningitis-encephalitis syndrome (AMES) to describe JE epidemiology and help inform policy decisions about possible immunization strategies for Bangladesh. During 2007–2016, a total of 6543 AMES patients were identified at four tertiary hospitals. Of the 6525 patients tested, 548 (8%) were classified as JE cases. These 548 patients resided in 36 (56%) out of 64 districts of Bangladesh, with the highest proportion of JE cases among AMES patients (12% and 7%) presenting at two hospitals in the northwestern part of the country. The median age of JE cases was 30 years, and 193 (35%) were aged ≤15 years. The majority of JE cases (80%) were identified from July through November. Surveillance results suggest that JE continues to be an important cause of meningo-encephalitis in Bangladesh. Immunization strategies including JE vaccine introduction into the routine childhood immunization program or mass vaccination in certain age groups or geographic areas need to be examined, taking into consideration the cost-effectiveness ratio of the approach and potential for decreasing disease burden. [ABSTRACT FROM AUTHOR]

• Self-cleaning approach towards enhancement of electrical efficiency. • Performance evaluation at five different volume flow rates. • Electrical efficiency enhanced from 9.89% to 11.91% as compared to PV only. • Maximum thermal efficiency found to be 77.60% at a mass flow rate of 2 LPM. This study experimentally investigates the potency of the designed and developed a photovoltaic thermal energy storage with self-cleaning (SC) sub-systems in improving the electrical efficiency of a solar photovoltaic system with thermal energy storage (PV-TES). The photovoltaic system with thermal energy storage (PV-TES) absorber is called double serpentine-flow channel, wherein phase change materials (PCM) thermal storage system has been integrated for better temperature control. An automatic self-cleaning system has been mounted on PV glass cover to clean the dust and ensure higher absorption of incident solar energy. The performance of self-cleaning assisted photovoltaic system with thermal energy storage (PV-TES-SC) has been studied under varied flow rate of 0.5 to 4 L per minute (LPM). Results shows that the PV-TES-SC attained a maximum thermal efficiency of 77.60% at a mass flow rate of 2 LPM. Else ways, the average maximum electrical efficiency of 11.91% was found at a mass flow rate of 4 LPM, whereas a PV alone system could deliver only 9.89% electrical efficiency. From the experimental results it can be confirmed that the PV-TES-SC system is efficient than a PV alone as a result of the newly introduced PCM thermal energy storage and self-cleaning system. [ABSTRACT FROM AUTHOR]

Abstract Amalgamation of thermal collector at the back of PV overcomes with low energy conversion efficiency issue upto some extent and improves overall efficiency of the systems. Use of phase change materials (PCM) in PV/T collectors as an intermediate thermal storage media offers a promising solution to this problem by storing large amount of heat. The aim of this research work was to design and develop a photovoltaic/thermal-phase change materials (PV/T-PCM) system and evaluate its energy, exergy and economic performance. Lauric acid as PCM contained in leak-proof aluminum foil packets are placed around the flow channel allowing extended period of thermal storage. The PV/T-PCM system has been studied at different volume flow rates viz. 0.5–4 L per minutes (LPM) to get the optimized performance of the system. Maximum thermal efficiency of PV/T-PCM collector was found to be 87.72% at 2 LPM. Maximum electrical efficiency of PV and PV/T-PCM systems has been found to be 9.88% and 11.08% (4LPM) respectively. The maximum exergy efficiency of PV and PV/T-PCM system has been found 7.09% and 12.19% (0.5 LPM) respectively. An economic analysis of the proposed system has also been carried out with a view to examine the feasibility of its commercialization. Highlights • Study of novel two side serpentine flow based photovoltaic/thermal (PV/T) with PCM. • Self-sufficient PVT-PCM system with improved energy and exergy efficiencies. • Economic evaluation of the PV/T collector using cash flow analysis. • Maximum thermal and exergy efficiency is found to be 87.72% and 12.19% respectively. [ABSTRACT FROM AUTHOR]

Abstract The behaviour of spudcan foundations during the installation and preloading in two-layer sand sediments was investigated through large deformation finite element (LDFE) analyses. The LDFE analyses were carried out using the coupled Eulerian-Lagrangian approach, modifying Mohr-Coulomb soil model to capture hardening and subsequent softening effects of sand. Parametric analyses were undertaken varying the top layer thickness, relative density of sand and spudcan diameter. Both loose to medium dense-over-dense and dense-over-loose to medium dense sand deposits were explored. The results showed that, for the investigated relatively thin top layer thickness of ≤ 5 m, spudcan behaviour was dictated by the bottom sand layer with a minimal influence of the top layer. For assessing the penetration resistance profile in two-layer sands, the performance of the ISO, SNAME, InSafeJIP, and other existing theoretical design methods were evaluated. [ABSTRACT FROM AUTHOR]

Abstract In this study, Zn x Cd 1-x S/CdTe solar cells were fabricated on commercially available indium tin oxide (In 2 O 3 : Sn or ITO) and fluorine doped tin oxide (SnO 2 : F or FTO) soda-lime glass (SLG) substrates by RF magnetron sputtering. Thin Zn x Cd 1-x S window layers with lower zinc (Zn) content in comparison to cadmium (Cd) were deposited by co-sputtering of ZnS and CdS targets concurrently by changing the radio frequency (RF) power of both during sputtering. CdTe thin films for the complete cells were also grown by sputtering with different thickness. Prior to fabricating the complete device, characterization for growth optimization of Zn x Cd 1-x S window layer and CdTe absorber layer was performed by utilizing Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Ultraviolet–visible spectroscopy (UV–Vis), Field Emission Scanning Electron Microscopy (FESEM) and Hall effect measurement system. Complete Zn x Cd 1-x S/CdTe solar cells were fabricated with the optimized growth conditions of window and absorber layers. The best cell fabricated on ITO coated SLG substrates showed an efficiency of 8.08% with significant open circuit voltage (V oc) of 882 mV. Highlights • Zn x Cd 1-x S and CdTe thin films have been deposited on ITO and FTO-coated soda lime glasses. • Changes in film quality are investigated by structural, optical and electrical properties. • Zn x Cd 1-x S/CdTe solar cells have been fabricated with the optimized growth conditions. • The best cell shows an efficiency of 8.08% with open circuit voltage of 882 mV. [ABSTRACT FROM AUTHOR]

This paper reports the results from three-dimensional dynamic finite element analysis undertaken to provide insight into the behaviour of a novel dynamically installed anchor (DIA), termed as fish DIA, during dynamic installation and monotonic pullout in non-homogeneous clay and calcareous silt. The fish DIA has an elliptic-shaped shaft, which reduces hydrodynamic drag resistance. The shaft is shaped to be thicker near the head to lower the mass centroid, and increase its diving potential with a specialised padeye position. A series of large deformation finite element analyses have been carried out considering the relevant range of parameters in terms of soil undrained shear strength; impact velocity, padeye offset ratio and pullout angle. Considering the difference in soil undrained shear strength, and DIA dimensions and mass; overall anchor tip embedment depths of the fish DIA lied in the range of that of the OMNI-Max DIA. The tracked anchor trajectory confirmed that, compared to the OMNI-Max DIA, the fish DIA dove deeper and earlier for a wide range of padeye offset ratio. These are more critical and beneficial for calcareous silt where the achieved embedment depths are generally lower compared to those in clay. [ABSTRACT FROM AUTHOR]

The behaviour of a torpedo anchor during dynamic installation in two-layered nonhomogeneous clay sediments was investigated through large-deformation finite-element (LDFE) analyses. Parametric analyses were undertaken varying the top layer thickness and strength ratio between two layers. Results show that the location of the demarcation point between the acceleration and deceleration phases of the anchor in the soil relative to the layer interface is the key factor directing the anchor behaviour in layered soils including the final embedment depth. Broadly speaking, the anchor behaviour in soft-over-stiff clay deposits is somewhat similar to that in single layer clay with strength increasing with depth. In stiff-over-soft clay deposits, the anchor penetrates deeper where the anchor deceleration phase (or the demarcation point) falls within the soft layer. Where the demarcation point lies within the top stiff layer, the anchor penetration depth decreases with increasing strength ratio, and the anchor penetration is terminated between the two layers for strength ratios ≥15. For assessing the anchor embedment depth in two-layered fine-grained ocean sediments in the field, an extended total energy-based method, along with a design expression, is proposed. [ABSTRACT FROM AUTHOR]

Phase change materials (PCMs) can be applied to several different solar energy systems for the extended heat energy storage which is quite useful as the solar energy is intermittent in nature and is unavailable during the night period. Application of PCMs in solar energy systems allows the solar energy to be used at any time even in the absence of the natural solar radiation. Thus, the use of PCMs in the solar energy systems can bridge the demand and supply gap of the normal electrical energy. This paper deals with the recent advances in PCMs application in different solar energy systems and presents almost all of the emerging areas where the applications of PCM in solar energy systems are urgently required. The novel and most recent developments of PCMs in solar thermal energy systems, such as, solar thermal power plants, solar air heater, solar water heater and solar cooker have been duly covered. Furthermore, the application of PCMs in heating and cooling of buildings have been presented as well as the investigation of the PCM application in the solar photovoltaic systems for the performance enhancement of PCMs. Intrinsically important, from the study it has been found that PCMs have been in use in almost all of the solar energy systems even though their uses are still limited and commercially not available due to several economic and environmental constraints. Thus, the paper attempts to present recent and novel approaches by the authors around the world on PCMs applications in the solar energy in well documented forms. Based on the findings, future recommendations have also been given to provide the idea and pragmatic concepts for the researcher to work on the areas of research for further improvements in the systems. [ABSTRACT FROM AUTHOR]

The interaction between a spudcan and an existing footprint is one of the major concerns during jack-up rig installation. The influence of spudcan-footprint interaction has recently been well addressed by a number of researchers. A lack of investigation exists in mitigating spudcan-footprint interaction issues. In the field, stomping and successive repositioning is conventionally used in installing a rig adjacent to an existing footprint. Water jetting and perforation drilling are also sometimes suggested. This paper reports a measure for easing spudcan-footprint interaction issues, with the efficiency of a spudcan with 4 slots tested through model tests carried out at 1 g on the laboratory floor. The soil conditions tested simulate soft to moderate seabed strength profiles close to the mudline, varying the undrained shear strength. The most critical reinstallation locations of 0.5D and 1D (D = spudcan diameter) and existing footprint depths of 0.33D and 0.66D were investigated. By comparing with a conventional spudcan, the spudcan with slots reduced the induced maximum moment, horizontal force, and horizontal sliding distance by up to 80%, 40%, and 98% respectively. Critically, no additional operations, such as stomping/repositioning, perforation drilling, water jetting, are required to be performed offshore. [ABSTRACT FROM AUTHOR]

This paper presents the performance of a Concentric Circular Antenna Array (CCAA) with robust optimal diagonal loading (ODL) technique. Because of the symmetrical configuration of a CCAA geometry, it enables the antenna array to scan azimuthally with minimal changes in its beam width and side-lobe levels. The performance of CCAA system is degraded in the presence of disparity between the original signal direction and the steering direction of the beamformer. This performance degradation problem due to look direction disparity can be improved by using robust techniques. This paper proposes the ODL technique for CCAA system and compare the performance of proposed robust CCAA processor with the existing CCAA processors. The proposed robust CCAA beamformer enhances the output power 28.12 dB and 8.624 dB at 2° disparity angle compared to the existing CCAA processor (Hossain et al., 2016) and robust CCAA beamformer (Reza et al., 2016) respectively. Numerical examples are presented to analyze the performance of proposed robust beamformer in different scenarios. [ABSTRACT FROM AUTHOR]

We explored the influence of nucleoside by-products (NBP) on blood chemistry, immune response, oxidative stress and intestinal morphology of Seriola dumerili. Four experimental diets were formulated where diets 1-3 are semipurified and supplemented with liquid NBP at concentration of 0 (D1, negative control), 30 (D2) and 90 (D3) g/kg. Diet 4 (D4) is a fishmeal-based positive control diet. Each diet was randomly allocated to triplicate groups of fish for 50 days. The results revealed a significant influence of NBP supplementations on total cholesterol, blood urea nitrogen and triglyceride level. Lysozyme activity (LA), total serum protein (TSP) and peroxidase activity (PA) also increased with NBP supplementation as compared to the negative control. TSP, PA and LA were numerically higher in diet groups D2 and D4, respectively. Anterior enterocyte height (hE) was higher in diet group D4, while NBP-supplemented groups showed intermediate values with D1 group and negative control group showed significantly lowest value. Supplementation of NBP also increased anterior fold height (hF) and microvillus height and posterior hF, hE and microvillus height compared with D1. Finally, we concluded that NBP can be used as a cheaper nucleotide/nucleoside source for amberjack. Supplementation of more than 30 g/kg in diets improved blood chemistry, non-specific immunity, oxidative stress resistance and intestinal morphology of amberjack. [ABSTRACT FROM AUTHOR]

Lentil, an important source of protein for human consumption, is considered as a salt susceptible crop species. Thus the present study was carried out to evaluate the most important lentil physiological characters that induce salt tolerance. Salt stress results in osmotic stress immediately followed by ionic toxicity. We used iso-osmotic solutions with different kinds of osmotica i.e. salt (NaCl and KCl), and polyethylene glycol (PEG) to identify the specific response of osmotic stress and ionic toxicity. All of these altered seedling height, chlorophyll, malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ), proline, reduced ascorbate (AsA) and total glutathione content, and ion uptake. Moreover, these osmotica also altered the activities of antioxidant enzymes such as catalase (CAT), ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR) and glutathione reductase (GR), except monodehydroascorbate reductase (MDHAR). Among different osmotica, only NaCl exhibited leaf chlorosis, reduction in K + and disruption in ion homeostasis, and increased MDA, H 2 O 2 and proline content than iso-osmotic KCl and PEG, indicating susceptibility of lentil seedling to salt stress. Addition of Ca along with NaCl showed no chlorosis and improved K + content. These results demonstrate that prevention of Na-induced K depletion in root might enhance salt tolerance in lentil. [ABSTRACT FROM AUTHOR]

A feeding trial was conducted to determine effects of dietary inosine on growth, immune responses, oxidative stress resistance and intestinal morphology of juvenile red sea bream. A semi-purified basal diet supplemented with 0 (D1, control), 2 g kg−1 (D2), 4 g kg−1 (D3), 6 g kg−1 (D4) and 8 g kg−1 (D5) dietary inosine, respectively, to formulate five experimental diets. Each diet was randomly allocated to triplicate groups of fish (initial weight: 8 g). After 50 days of feeding trial, fish fed diets with 4 g kg−1 inosine had the highest ( p < .05) final weight, weight gain and specific growth rate. Similarly, improved feed intake, feed conversion ratio and protein efficiency ratio were also found at 4 g kg−1 inosine supplemented group. Some non-specific immune parameters such as total serum protein, lysozyme activity and bactericidal activity tended to be higher for fish fed diets supplemented with inosine. Peroxidase and catalase activity also influenced ( p < .05) by dietary inosine supplementation. Fish fed 2 g kg−1 and 4 g kg−1 inosine supplemented diets showed the least oxidative stress condition. Inosine supplementation significantly increased ( p < .05) anterior enterocyte height and posterior fold height, enterocyte height and microvillus height compared with control. We concluded that 4 g kg−1 dietary inosine supplementation effectively provokes growth and health performance of red sea bream by increasing growth, immune response, oxidative stress resistance and intestinal health condition. [ABSTRACT FROM AUTHOR]

Spudcan punch-through during installation and preloading process is one of the key concerns for the jack-up industry. This incident occurs in layered deposits, with new design approaches for spudcan penetration in sand-over-clay deposits reported recently. This paper reports a novel design approach for spudcan penetration in stiff-over-soft clay deposits. Large-deformation finite element (LDFE) analyses were carried out using the Coupled Eulerian-Lagrangian (CEL) approach. The clay was modelled using the extended elastic - perfectly plastic Tresca soil model allowing strain softening and rate dependency of the undrained shear strength. A detailed parametric study was undertaken, varying the strength ratio between bottom and top soil layers, the thickness of the top layer relative to the spudcan diameter, and degree of nonhomogeneity of the bottom layer. Existing data from centrifuge model tests were first used to validate the LDFE results, and then the measured and computed datasets were used to develop the formulas in the proposed design approach. The approach accounts for the soil plug in the bottom layer, and the corresponding additional resistance. Where there is the potential for punch-through, the approach provides estimations of the depth and bearing capacity at punch-through, the bearing capacity at the stiff-soft layer interface, and the bearing capacity in the bottom layer. Comparison shows that the punch-through method suggested in ISO standard 19905-1 provides a conservative estimate of the bearing capacity at punch-through, with guidelines provided to improve the method. [ABSTRACT FROM AUTHOR]

This study focuses on easing or eliminating potential punch-through in two-layer stiff-over-soft clay deposits by tweaking spudcan shapes. The effectiveness of skirted spudcans with and without holes, relative to a generic spudcan used conventionally, is tested. Three-dimensional large deformation finite element (LDFE) analyses are carried out systematically; encompassing a parametric study on the length of the skirt on the bottom periphery, number of holes through the spudcan base, and the slope of the spudcan base. Numerical results lead to selection of two skirted spudcans with and without holes, and both with a skirt length of ∼0.23 spudcan diameter. The performance of those two spudcans is then tested through a series of centrifuge model tests; varying the strength ratio between the two layers, and the thickness of the stiff layer relative to the spudcan diameter. Overall, the results of eighteen penetration tests suggest that the skirted spudcan without holes is more effective in easing or even eliminating the punch-through that is associated with the penetration of the generic spudcan. For using the skirted spudcan without holes in the field, an improved analytical model is proposed for assessing penetration resistance profile or embedment depth under a given preload. • US$5–50 million/incident costing jack-up rig punch-through failure. • Easing or mitigation of punch-through failure. • Stratified stiff-over-soft clay deposits. • Tweaking spudcan shape. • Combined centrifuge modelling and large deformation finite element analyses. [ABSTRACT FROM AUTHOR]

Smart grid engineering is the key for a beneficial use of widespread energy resources, it is a modernized electrical grid that uses analog or digital information and communications technology. Renewable energy itself a thrust area of research due to its availability, applicability and environmental friendly nature and the application of smart grid in renewable energy makes it vast and more promising. This fusion enables the efficient use of renewable energies which is a key challenge for now. The present review paper attempts to investigate the role of smart grid in the renewable energy. The introductory section sets the role of renewable energy and distributed power in a smart grid system. Subsections cover the concept and availability of renewable energies, renewable energy power calculation formulae, smart grid concepts and its feasibility, case studied as performed by different researchers around the World, discussion and future recommendations and finally the conclusions from the study. To achieve this, articles from different sources such as internet, reports, conferences and journals of Elsevier, Springer, Tailor and Franacis, Wiley and many more have been collected and reviewed. This paper concludes that renewable energies can be used efficiently and in a smart way by using the smart grids. However, the smart grid technology is not mature enough and needs more research on the same. [ABSTRACT FROM AUTHOR]

The interaction between a spudcan and an existing footprint is a major concern during jack-up rig installation. No guidelines were provided in the recently finalised version of ISO guidelines 19905-1 in regards to mitigating spudcan–footprint interaction issues except some proposed considerations due to scarce of detailed investigation. This paper reports a measure for easing spudcan–footprint interaction issues, with the efficiency of perforation drilling tested through model tests carried out at 1 g. The soil conditions tested simulate soft seabed strength profiles close to the mudline, varying the undrained shear strength. The most critical reinstallation locations of 0.5 D and 1 D ( D =spudcan diameter) and existing footprint depth of 0.33 D were investigated. The removal of soil (through perforation) inside the spudcan perimeter, with an area of 9% perforated, reduced the induced maximum moment, horizontal force, and horizontal sliding distance by up to 80%, 83%, and 76% respectively. [ABSTRACT FROM AUTHOR]

Seagrass mapping and monitoring using remote sensing has been established using various imageries and mapping methods, ranging from complex optical modeling to manual interpretations. Few attempts have been made to find relations between spatiotemporal changes within seagrass habitats and their surrounding environment in the mapping efforts. In this study, issues of spatiotemporal changes in seagrass habitat including water quality, and causes and processes of seagrass degradation were addressed through assessing the ability of integrated manual enhancement and seed pixel growing techniques on multi-date Landsat images for mapping and monitoring seagrass resources. This integrated approach was tested on a total of forty-nine Landsat 5, 7 and 8 images of the seagrass meadow spatial distribution and cover change analysis for Punag-Sari estuary (Lawas), Pengkalan Nangka (Kelantan) lagoon, and Paka (Terengganu) lagoon of Malaysia. The resulted maps demonstrated the ability of Landsat images for producing spatially extensive maps and allowed quantitative estimation of seagrass coverage, accretion/erosion, and describe changes in noticeable areas. The findings indicated that a noticeable loss of seagrass habitats at varying magnitude occurred between 2000 and 2014 for Punang-Sari, between 1998 and 2014 for Pegkalan Nangka, and between 1988 and 2014 for Paka. The natural event mainly sand shifting was the main cause of seagrass habitat loss for Punang-Sari Lawas. Coastline change was identified as the most significant factor that caused seagrass spatial cover loss of the Pengkalan Nangka lagoon. The seagrass meadows of Pengkalan Nangka and Paka were greatly affected by natural events including floods, and local human-induced interferences such as dredging, and sand mining. The mapping approach and the map products presented in this paper will be a useful information source for the coastal management agencies involved in monitoring and management programs. [ABSTRACT FROM AUTHOR]

Torpedo anchors (of diameter ~1 m) are released from a height of 50–100 m from the seabed, achieving velocities up to 35 m/s at impacting the sediment. The strain rates induced in the surrounding soil by this dynamic installation is therefore significantly higher than those associated with installation of other offshore foundations and anchoring systems. The high strain rates enhance the mobilised undrained shear strength compared to that measured by in-situ penetrometer or laboratory tests. This paper reports the results from dynamic installation of a torpedo anchor in strain softening, rate dependent soft clays, quantifying the effects relative to results for ideal Tresca material. The three-dimensional dynamic large deformation finite element (LDFE) analyses were carried out using the coupled Eulerian–Lagrangian approach. The simple elastic-perfectly plastic Tresca soil model was modified to allow strain softening and strain rate dependency of the shear strength. Parametric analyses were undertaken varying the strain rate parameter, the sensitivity and ductility of the soil, and the soil undrained shear strength. Overall, embedment depth for rate dependent, strain softening clays lay below that for ideal Tresca material. Increased strain rate dependency of the soil led to marked reduction in embedment depth, only partly compensated by brittleness. Key results have been presented in the form of design charts, fitted by simple expressions to estimate the embedment depth of a torpedo anchor. [ABSTRACT FROM AUTHOR]

This paper reports the results from three-dimensional dynamic finite element analysis undertaken to provide insight into the behaviour of torpedo anchors during dynamic installation in non-homogeneous clay. The large deformation finite element (LDFE) analyses were carried out using the coupled Eulerian–Lagrangian approach, modifying the simple elastic-perfectly plastic Tresca soil model to allow strain softening, and incorporate strain-rate dependency of the shear strength using the Herschel–Bulkley model. The results were validated against field data and centrifuge test data prior to undertaking a detailed parametric study, exploring the relevant range of parameters in terms of anchor shaft length and diameter; number, width and length of fins; impact velocity and soil strength. The anchor velocity profile during penetration in clay showed that the dynamic installation process consisted of two stages: (a) in Stage 1, the soil resistance was less than the submerged weight of the anchor and hence the anchor accelerated; (b) in Stage 2, at greater penetration, frictional and end bearing resistance dominated and the anchor decelerated. The corresponding soil failure patterns revealed two interesting aspects including (a) mobilization of an end bearing mechanism at the base of the anchor shaft and fins and (b) formation of a cavity above the shaft of the installing anchor and subsequent soil backflow into the cavity depending on the soil undrained shear strength. To predict the embedment depth in the field, an improved rational analytical embedment model, based on strain rate dependent shearing resistance and fluid mechanics drag resistance, was proposed, with the LDFE data used to calibrate the model. [ABSTRACT FROM AUTHOR]

A cryogenic pipeline is a pipe-in-pipe with larger outer diameter, and is heavier and stiffer, compared to conventional deepwater steel flowlines or export pipelines. Cryogenic pipelines are being considered to be placed on shallow water sandy seabeds for transporting liquefied natural gas to shore. This paper reports a series of centrifuge tests to assess the as-laid embedment of a cryogenic pipeline during the dynamic laying process, and the uplift capacity of a trench-laid pipeline. Two seabed conditions were tested – a pipe laid onto the base of a trench and a flat silica sand deposit. A total of 12 dynamic pipe laying tests were conducted varying vertical force and pipe oscillation amplitude, frequency and number of cycles; encompassing typical laying processes. The embedment depth was found to be less than 0.5 diameters, owing to the resultant effect of lateral ploughing and sand densification. For the trench-laid cases, after the completion of simulating the pipe laying process, the trench was filled with a layer of sand and a layer of rock armour; varying the thickness of the layers. The pipe was then extracted vertically to evaluate the uplift resistance, which was shown to increase with increasing the thickness of the rock layer. • Laying of cryogenic pipelines on sandy seabed. • Surface and trench laying. • Dynamic embedment during laying in sand. • Optimum thickness of rock armour. • Uplift capacity. [ABSTRACT FROM AUTHOR]

Methods to predict and fill Landsat 7 Scan Line Corrector (SLC)-off data gaps are diverse and their usability is case specific. An appropriate gap-filling method that can be used for seagrass mapping applications has not been proposed previously. This study compared gap-filling methods for filling SLC-off data gaps with images acquired from different dates at similar mean sea-level tide heights, covering the Sungai Pulai estuary area inhabited by seagrass meadows in southern Peninsular Malaysia. To assess the geometric and radiometric fidelity of the recovered pixels, three potential gap-filling methods were examined: (a) geostatistical neighbourhood similar pixel interpolator (GNSPI); (b) weighted linear regression (WLR) algorithm integrated with the Laplacian prior regularization method; and (c) the local linear histogram matching method. These three methods were applied to simulated and original SLC-off images. Statistical measures for the recovered images showed that GNSPI can predict data gaps over the seagrass, non-seagrass/water body, and mudflat site classes with greater accuracy than the other two methods. For optimal performance of the GNSPI algorithm, cloud and shadow in the primary and auxiliary images had to be removed by cloud removal methods prior to filling data gaps. The gap-filled imagery assessed in this study produced reliable seagrass distribution maps and should help with the detection of spatiotemporal changes of seagrasses from multi-temporal Landsat imagery. The proposed gap-filling method can thus improve the usefulness of Landsat 7 ETM+ SLC-off images in seagrass applications. [ABSTRACT FROM AUTHOR]

Spudcan foundations of various geometries are commonly used in the field for supporting offshore oil and gas drilling (jack-up) rigs. This paper investigates the effect of the spudcan and its base geometry on the penetration and extraction resistance in soft normally and lightly overconsolidated clay. A series of centrifuge tests was undertaken on model spudcans of three different geometries typically used in the field. The spudcans were extracted from penetrations of 2·64∼3 (area equivalent) diameters and after an operation period of ∼19 months. Additional large-deformation finite-element analyses allowed for exploring a range of spudcan base geometries. Corresponding field data were accumulated. The results from this study have confirmed the accuracy of the assumption of a circular conical-based footing and the use of area equivalent diameter for assessing spudcan penetration resistance, as suggested by ISO guidelines 19905-1. Simulation of a flat-based circular plate resulted in 19% higher resistance compared to that of conical-based footings. For spudcans with cutouts and with a peripheral skirt, maximum penetration resistances were, respectively, 14 and 12% lower, and maximum extraction resistances were 20 and 14% lower compared to those for a general spudcan. The corresponding required jack-up leg length was 9 and 7% higher. The effect of peripheral skirt length was shown to be minimal (at least for length relative to spudcan diameter ≤ 0·42). [ABSTRACT FROM AUTHOR]

Challenges associated with dynamically installed anchors include prediction of the anchor embedment depth, which dictates the anchor's holding capacity. This is particularly true for calcareous sediments, as very little performance data exist for this anchor type in these soils. This paper reports results from a series of model tests undertaken to provide insight into the behaviour of a torpedo anchor during dynamic installation and monotonic pullout in lightly overconsolidated calcareous silt. The tests were carried out in a beam centrifuge, varying the drop height and consequently the impact velocity, and the consolidation period prior to anchor pullout. The mudline load inclination was also varied to encompass various mooring configurations. The centrifuge model test data were used to calibrate: () an analytical dynamic embedment model, based on conventional bearing and frictional resistance factors but with strain-rate-dependent undrained shear strength for the soil; and () an analytical quasi-static vertical pullout capacity model, accounting for reverse end bearing and frictional resistance. A total energy based expression, appropriate for calcareous silts, was proposed for predicting anchor embedment depth for a given anchor geometry, mass and impact velocity. For assessing anchor vertical holding capacity, a piezocone based direct design approach was also proposed, deriving anchor end bearing and frictional resistance from cone tip resistance and sleeve friction, respectively. Anchor capacity under inclined loading was presented as failure envelopes expressed in terms of dimensionless vertical and horizontal components of anchor net resistance, which agreed well with a finite-element based envelope developed for embedded foundations. The regain of anchor capacity was found to be in good agreement with predictions based on the cavity expansion framework. [ABSTRACT FROM AUTHOR]

This review evaluates various methods employed to produce seagrass habitat maps using optical and acoustic remote-sensing (RS) techniques coupled within situsampling to highlight recent advances and to define areas where potential future research should be focused in the application of RS technologies. A critical review of 195 studies revealed that, in the past four decades, advances in the application of RS methods, notably using Landsat imagery, are identified for seagrass detection, assessment of areal coverage, distribution and abundance mapping, and the detection of extent and biomass changes, as illustrated in peer-reviewed literature. Rapid technological and methodological advances have occurred in the acquisition and interpretation of optical and acoustic data for the mapping of seagrass habitats. The methods have been tested to segment, classify, and combine RS data with biological field or ground truth sample data. There is no single technology or approach that is suitable for and capable of measuring all seagrass parameters (presence/absence, cover, species, and biomass) and assessing change. Integration of field, imagery, and mapping approaches is therefore required. Further research is required for continued improvements in understanding of theoretical and methodological aspects of seagrass RS. [ABSTRACT FROM PUBLISHER]

Mitigation of spudcan punch-through is one of the principal aspects for inclusion in the ISO standard 19905-1. This paper investigates the potential for using skirted foundations as an alternative to spudcans in an attempt to mitigate punch-through failure of jack-up rigs during installation and preloading in sand-over-clay deposits. A series of centrifuge model tests is undertaken on a spudcan and two skirted foundations, varying the length of the skirt relative to the foundation diameter. The thickness of the sand layer is also varied to cover a range of practical interest. The results from this study confirm that the use of skirted foundations as an alternative to spudcans can eliminate the potential of punch-through failure on sand-over-clay deposits. The degree of post-peak bearing reduction, one of the key measures of the severity of punch-through failure, is shown to be linked directly to the effective sand layer thickness beneath the foundations. Skirted foundations assist in mitigating the severity of punch-through failure by reducing the effective sand layer thickness. [ABSTRACT FROM AUTHOR]

Highly layered soils are prevalent in several areas of current offshore activity and in particular in emerging provinces and fields. However, no investigation has been carried out for spudcan penetration in stratified sediments with more than two layers. This paper reports centrifuge modelling of spudcan foundations penetrating through 3∼6 clay layers with interbedded stronger clay, silica sand and carbonate sand layers. The aim was to provide insight into the behaviour of spudcan foundations in stratified sediments comprising layers of different drainage conditions and mineralogy. The motivation for this paper emanated directly from the future needs identified by the recent revised version of ISO 19905-1. It was found that the downward soil deformation was extended into 3∼4 underlying layers of sand and clay with thickness ratios (/) less than 0·6. The limiting squeezing depth was 0·17∼0·18 when approaching stiff clay-moderate clay layers and 0·28 when approaching dense sand-stiff clay layers. These depths were enhanced (to 0·3∼0·35) by the soil plug trapped beneath the advancing spudcan. The values obtained using the ISO criteria either overestimated or underestimated these depths. Punch-through failure at a shallow penetration depth occurred with a load-spreading gradient of 1 (horizontal):3 (vertical) in silica sand and with a much smaller gradient of 1:7 in carbonate sand. In both sands, the spreading angle reduced with increasing depth of punch-through failure, and diminished quickly immediately after a failure. In contrast to ISO guidelines, the plug base, where the end bearing was mobilised, was located in one of the lower layers moved down with the advancing spudcan. For all cases, a soil plug developed at the base of the advancing spudcan, with the height of the plug accumulating through trapped clay and sand, regardless of their strength, from layers above and below the advancing spudcan. The height of a soil plug was reduced partly by soil backflow and squeezing out from contact with a strong layer. The observed soil failure mechanisms and corresponding penetration resistance profiles highlight uncertainties in ISO 19905-1. Guidelines are provided to improve the suggested punch-through and squeezing methods in ISO 19905-1. Implications for the bottom-up design approach proposed by ISO, and also a top-down design approach used by some practitioners, are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Zinc cadmium sulfide (ZnxCd1−xS) thin films (0≤x≤1) were deposited by the radio frequency (RF) co-sputtering of cadmium sulfide (CdS) and zinc sulfide (ZnS). The RF powers of CdS and ZnS were varied to control the composition of the films, which was confirmed using energy dispersive X-ray analysis. The structural properties of the films were investigated using X-ray diffraction, which showed that the films have a hexagonal (wurtzite) structure with a strong preferential orientation along the (002) plane. The values of lattice constants ‘a’ and ‘c’ decreased as ‘x’ increased. The surface morphology, topology and optical properties were investigated using field emission scanning electron microscopy (FESEM), atomic force microscopy and ultraviolet spectrophotometry. The FESEM studies revealed an increase in grain size for zinc (Zn) contents up to x=0.62, followed by a decrease in the grain size until ‘x’ reached 0.81, above which the films were amorphous. The optical band gaps of the films were obtained from optical absorption measurements and shifted to a higher energy as the content of ‘x’ increased. The presence of a small amount of zinc in CdS strongly influenced the optical band gap and transmittance of ZnxCd1−xS thin films. The electrical sheet resistance of the films was also found to be relatively high. Among the range of ZnxCd1−xS compositions tested, the samples with a Zn content of 0.17 to 0.43 showed a better film quality, making them suitable as the window layer in ZnxCd1−xS/CdTe thin film solar cells. [Copyright &y& Elsevier]

The structural and electrical properties of the magnetron sputtered CdTe thin films with subsequent CdCl2 solution treatment have been studied with a major focus on the influence of CdCl2 treatment to achieve high quality thin films. In this study, CdTe films with a thickness of 1.5 to 2μm have been grown using the magnetron sputtering technique on top of glass substrate at an optimized substrate temperature of 250°C. Aqueous CdCl2 concentration varied from 0.3mol to 1.2mol with the annealing temperature from 360°C to 450°C. The surface roughness of the films increases with the increase of solution concentration, while it fluctuates with the increase of annealing temperature. The density of nucleation centers and the strain increases for the films treated at 360°C with 0.3M to1.2M while the grain growth of the films reduces. However, these strains are released at higher annealing temperatures, resulting in reduced dislocation densities, structural defects as well as increased crystalline property and grain size. The carrier concentration increases with the increase of treated CdCl2 concentration and subsequent annealing temperature. The highest carrier concentration of 1.05×1014/cm3 was found for the CdTe thin films treated with 0.3M CdCl2 solution followed by an annealing treatment at 420°C for 20min. [ABSTRACT FROM AUTHOR]

Earthmoving equipment working on a progressively placed cover layer over mine tailings often experiences catastrophic 'rotational' (or 'punch-through') failure, with potential for loss of the equipment and harm to the operator. Although the performance of foundations on a homogeneous sand or clay slope is routinely calculated and investigated, comprehensive investigation of a thin, stronger slope overlying a softer layer is scarce. This paper reports the results of centrifuge model tests undertaken to provide insight into strip foundation behaviour during penetration, with freedom in horizontal displacement and rotation, adjacent to a sand embankment (cover layer), into a weaker clay layer (representing mine tailings). Variables were the set-back of the edge of the foundation from the crest of the slope, the height of the slope relative to the foundation size, and the normalised strength of the lower clay layer. Soil movement was captured continuously by a digital camera, and subsequently quantified through particle image velocimetry (PIV) analysis. The load-penetration responses were separately recorded. The effect of normalised set-back ratio ( = /), slope height ( = /) and clay strength ( / ) on the evolving soil flow mechanisms and the penetration resistance profile is discussed in the context of the likelihood and severity of failure. Rotational failure, with a peak in penetration resistance followed by some reduction, occurred for all cases investigated except for a higher set-back of = 1·5. The severity of failure was greater the closer the proximity of the footing to the slope crest, and the greater the height of the slope, whereas it reduced as the normalised strength of the lower layer increased. Typical critical failure occurred in clear shear planes pushing a (nominally) rigid block of soil, with the shape of a hemisphere followed by a wedge, towards the slope. [ABSTRACT FROM AUTHOR]

Abstract: Background: Persons with primary immunodeficiency disorders (PIDD) who receive oral poliovirus vaccine (OPV) or are household contacts of OPV recipients are at risk of excreting immunodeficiency-associated vaccine-derived polioviruses (iVDPVs). iVDPVs can be transmitted and cause paralytic polio. The objective of this study was to determine the feasibility of identifying infants and young children with PIDD in Bangladesh, and among those identified, to estimate the proportion excreting iVDPVs. Methods: Patients admitted at 5 referral and teaching hospitals from the hospital catchment area were screened for PIDD using a standardized clinical case definition. PIDD was confirmed using results of testing for age-specific quantitative immunoglobulins (QIGs) levels. Stool specimens were collected according to WHO guidelines from children with confirmed PIDD. Results: During February–July 2009, 13 patients were identified who met the clinical case definition for PIDD; their median age was 1.4 years (range: 2 months to 10 years). Six (46%) of the patients had age-specific QIG results that confirmed PIDD. Stool specimens from four patients tested negative for polio vaccine viruses. All four had received OPV between 50 and 264 days prior to study recruitment. Conclusion: Identifying children with PIDD at referral and teaching hospitals in Bangladesh is feasible, but a larger number of patients is needed to estimate the risk for iVDPV excretion. The national polio eradication program should expand surveillance for PIDD case-patients and regularly test persons with PIDD for poliovirus excretion. These efforts will be essential for developing effective prevention and control strategies following OPV cessation, especially for densely populated and tropical countries like Bangladesh where even a minimal iVDPV risk could have significant public health consequences. [Copyright &y& Elsevier]

Structural stiffeners placed inside caissons have created significant uncertainty regarding soil flow mechanisms, side friction, and end bearing, and consequently in the prediction of the underpressure required for installation. This paper describes centrifuge modelling of the penetration of stiffened skirts in overconsolidated clay, identifying the soil flow mechanisms around and between stiffeners and the penetration resistance. The effects of stiffener width and spacing as well as soil strength ratio are discussed. The present guidelines for predicting the point of soil backflow in the gap that forms between the stiffeners are shown to be invalid and a new expression, based on a stability factor ( su/ γ′ B, where su and γ′ are the undrained shear strength and effective unit weight of the soil, respectively, and B is the combined width of the skirt and stiffener close to the caisson tip) is proposed. End bearing at the skirt tip and base stiffener are seen to dominate installation resistance. The normalized installation resistance stabilizes at a value of ∼17.5 at deep penetrations and is shown to be independent of whether the cavity between the stiffeners remains open or is backfilled with a soil-water mixture. This factor of 17.5 is shown to be in good agreement with reported field data and centrifuge test data and hence may be used to obtain a first-order estimate of the installation resistance of a caisson with stiffeners. [ABSTRACT FROM AUTHOR]

'Spudcan' foundations for mobile drilling rigs continue to exhibit a high failure rate in the offshore oil and gas industry. The more frequent use of larger jack-ups in highly stratified regions, such as the Sunda Shelf in Southeast Asia, contributes to this concerning increase in 'punch-through' incidents, which can lead to buckling of a leg or even toppling of the rig. An industry practice known as 'perforation drilling' is sometimes used to mitigate the punch-through risk in layered clays, extracting soil from the upper strong layer before the jack-up is installed. This paper reports results from centrifuge model tests exploring the efficiency of perforation drilling. The soil conditions tested simulate offshore strength profiles that have reported punch-through failures. An experimental method for 'drilling' sites in an enhanced gravity centrifuge environment was developed and the installation responses of model spudcan foundations penetrating through multi-layered clays with interbedded stiff layers were recorded. The experimental results show that the removal of soil inside the spudcan perimeter, with an area of 9% perforated, eliminated rapid leg run and severe punch-through on the two- and four-layer seabed profiles tested. This confirms the effectiveness of perforation drilling and indicates how the offshore drilling plan may be optimized. [ABSTRACT FROM AUTHOR]

Abstract: The effect of thermal conductivity of the absorber plate of a solar collector on the performance of a thermo-siphon solar water heater is found by using the alternative simulation system. The system is assumed to be supplied of hot water at 50°C and 80°C whereas both are used in domestic and industrial purposes, respectively. According to the Rand distribution profile 50, 125 and 250l of hot water are consumed daily. The condition shows that the annual solar fraction of the planning functions and the collector''s configuration factors are strongly dependent on the thermal conductivity for its lower values. The less dependence is observed beyond a thermal conductivity of 50W/m°C for the solar improper fraction and above 100W/m°C for the configuration factors. In addition, the number of air ducts and total mass flow rate are taken to show that higher collector efficiency is obtained under the suitable designing and operating parameters. Different heat transfer mechanisms, adding natural convection, vapor boiling, cell nucleus boiling and film wise condensation is observed in the thermo-siphon solar water heater with various solar radiations. From this study, it is found that the solar water heater with a siphon system achieves system characteristic efficiency of 18% higher than that of the conventional system by reducing heat loss for the thermo-siphon solar water heater. [Copyright &y& Elsevier]

Abstract: The purpose of this study is to evaluate performance cement of production and cement kiln. The design of energy efficient dryers employing heat pump systems and the dynamic response of the product to the kiln conditions must take into account. In this paper, the formulation of a dynamic and kiln-wide drying model is described. The model predictions have been verified by comparing them with the published experimental data. The model is then used to simulate performance of three industrial kilns. Numerical experiments are carried out to investigate influence of key operating and design parameters on energy consumption of kilns. The model is also used to explore the possibility of manipulating temperature profile within the kiln to reduce energy consumption per tonne of clinker. Cement kiln dust is a fine-grained material produced during the manufacture of cement. At present reuse option is limited and the bulk of cement kiln dust that is not reused in the cement manufacturing process is sent to landfills or stored on-site. Due to the calcium oxide (CaO) content of cement kiln dust, it has the potential to be used as a replacement for lime in treating acidic wastewaters such as acid rock drainage. Slaking of two of the cement kiln dust samples with the highest free lime contents (e.g., 34% and 37% free of CaO) gave elevated pH values statistically comparable to those of the commercial quicklime sample that was characterized as having 87% of CaO. Acid neutralization trials indicate that cement kiln dust samples with low free lime contents could be effective at neutralizing acidic wastewaters. [Copyright &y& Elsevier]

1. The objective of the study was to investigate the effect of dietary karaya saponin on cholesterol deposition in laying hens. 2. A total of 40 Boris Brown hens were randomly assigned at 20 weeks of age to 4 treatment groups and fed on diets supplemented with 0 (control), 25, 50 or 75 mg/kg karaya saponin for an 8-week experimental period. 3. After 8 weeks of dietary supplementation, karaya-saponin-treated groups had significantly lower serum cholesterol (23·0%) and triglycerides but increased high density lipoproteins cholesterol concentration than controls, irrespective of karaya saponin content in the diet. Egg yolk cholesterol and triglycerides were also significantly reduced by dietary karaya saponin. Hepatic cholesterol and triglycerides were significantly reduced by karaya saponin but bile acids concentration in the faeces and liver were significantly increased by karaya saponin. The concentrations of oleic, linoleic and linolenic acids in the yolk were greater in hens receiving karaya saponin than in controls. Karaya saponin significantly increased egg production, feed efficiency and yolk colour compared with controls. Karaya saponin tended to increase egg weight, feed consumption, Haugh units, albumen weight and yolk index. 4. In conclusion, karaya saponin is a potential agent for reducing yolk cholesterol concentration together with an overall increase of production performance and improvement in egg quality. [ABSTRACT FROM AUTHOR]

1. It has been reported that karaya saponin and Rhodobacter capsulatus individually have hypocholesterolaemic activity in laying hens. This study focuses on the effect of adding karaya saponin with R. capsulatus to hen's diet with regard to serum and egg yolk cholesterol and triglycerides. 2. A total of 56 Boris Brown laying hens were divided into 7 groups at 20 weeks of age. Combinations of 25, 50, 75 mg kg-1 karaya saponin and R. capsulatus 200 and 400 mg kg-1 were used as treatment groups. 3. After 8 weeks of supplementation, the effects of all the combinations of karaya saponin and R. capsulatus on serum and egg yolk cholesterol, triglycerides, and high-density lipoprotein (HDL)-cholesterol were greater than either karaya saponin or R. capsulatus alone. The combination of karaya saponin 50 mg kg-1+ R. capsulatus 400 mg kg-1 exhibited the greatest reduction of serum (32⋅5%) and yolk (22⋅5%) cholesterol and the greatest increase of faecal, liver bile acids and yolk fatty acid (oleic, linoleic and linolenic) concentrations. In addition, egg production and yolk colour were significantly improved by the combined use of karaya saponin and R. capsulatus supplementation. 4. Therefore, the dietary supplementation of karaya saponin and R. capsulatus may lead to the production of a low-cholesterol egg, with production performance maintained at a standard level. [ABSTRACT FROM AUTHOR]

This paper presents results of large deformation finite element (LDFE) analyses that investigate the penetration response of deep-penetrating spudcan foundations in stratified soil comprising a strong clay layer overlying weaker clay. Such strength profiles give rise to potential punch-through failure, with a local maximum penetration resistance followed by some reduction. The paper is a companion paper to one that presents results from centrifuge model tests of the same problem, with the overall aim being to investigate the potential for punch-through failure and its severity, as a basis for improving design methods for evaluating spudcan penetration. The LDFE analyses have simulated continuous penetration of smooth and rough spudcan foundations from the sea-bed surface. A detailed parametric study has been undertaken, exploring the relevant range of layer thickness (relative to the spudcan diameter), strength ratios and spudcan base roughness. The results have been validated against previously published results and the centrifuge test data presented in a companion paper. Excellent agreement was obtained between the results from LDFE analyses and centrifuge tests. As the ratio of the shear strength of the bottom layer to that of the top layer decreased, upwards soil flow around the spudcan shoulder became less pronounced and the failure mechanism was dominated by a steep-sided plug of soil from the top layer being forced deep into the lower layer. The potential for severe punch-through was demonstrated by a significant reduction in the resistance profile as the spudcan approached the interface between the two layers. A preliminary design chart is proposed to estimate the cavity depth above the penetrating spudcan, which was significantly greater than that for a single layer clay. The penetration responses have been presented in terms of profiles of normalised net bearing pressure for a range of layer geometries and soil properties. Potential punch-through occurred for all cases where the strength ratio was less than or equal to 0·6, with the reduction in resistance being greater the lower the strength ratio of the underlying layer to the upper layer, and the thicker the upper layer, but reducing as the strength gradient in the lower layer increased. The current approach suggested in offshore design guidelines is shown to underestimate the penetration resistance significantly, in most cases, and give poor estimates of the likelihood and severity of spudcan punch-through. [ABSTRACT FROM AUTHOR]

Installation of independent-legged jack-up rigs in sea-bed sediments where a strong layer overlays weaker soil can lead to catastrophic 'punch-through', with potential leg buckling or toppling of the unit. Although approximate methods of analysis exist for estimating the penetration resistance, these do not account for the distortion of the upper layer as it punches through into the lower layer and there has been only limited visual depiction of the failure mechanism that occurs for the case of strong clay overlying weaker soil. This paper reports results of centrifuge model tests undertaken to provide insight into spudcan foundation behaviour during undrained vertical penetration through a stronger clay layer into weaker material, varying the strength ratio between lower and upper soil layers, the thickness of the upper layer relative to the spudcan diameter and the strength gradient of the lower layer. The model tests included half-spudcan tests against a transparent window, allowing the soil flow to be captured continuously by a digital camera and subsequently quantified through particle image velocimetry (PIV) analysis, and separate full-spudcan tests to measure the penetration resistance. Four interesting aspects of the soil flow mechanisms were identified: () vertically downwards motion of the soil and consequent deformation of the layer interface; () trapping of the stronger material beneath the spudcan, with this material being carried down into the underlying soft layer; () delayed back-flow of soil around the spudcan into the cavity formed above the spudcan; () eventual localised flow around the embedded spudcan. The effect of normalised layer soil properties and geometry on the soil flow mechanisms and the form of the penetration resistance profile is discussed in the context of the likelihood and severity of punch-through failure. Typical critical failure modes involved punching shear, with clear shear planes in the shape of a truncated cone forming in the upper layer below the spudcan. Potential punch-through, with a peak in penetration resistance followed by some reduction, occurred for almost all cases investigated. The reduction in resistance became more severe as the strength ratio of the underlying layer to the upper layer reduced, and also as the upper layer thickness increased. The failure modes assumed by the currently available recommended practices are not consistent with those observed from the study, suggesting a more rational approach is needed. [ABSTRACT FROM AUTHOR]

Abstract: The installation of independent-leg jack-up rigs in seabed sediments where a strong layer overlays weaker soil can lead to a catastrophic ‘punch-through’ event, with potential leg buckling or toppling of the unit. In an attempt to mitigate this risk in layered clays, an industry practice known as ‘perforation drilling’ is sometimes used. This process is also colloquially referred to as Swiss cheese drilling. The rationale is to reduce the bearing resistance of the upper stiff layer by perforating it with drill holes. Although drilling directly underneath the spudcan is reported to ease punch-through, little guidance to how many or where drill holes should be located is available. This paper reports two series of model tests of a 40 mm diameter () spudcan footing vertically installed in a stiff-over-soft clay deposit. In this preliminary study, the effectiveness of perforation drilling was investigated by drilling holes of different spacing, depth and distribution both underneath and outside the immediate perimeter of the penetrating spudcan. Drilling patterns were chosen to not just follow the conventional method of holes directly below the spudcan, but to coincide with failure mechanisms previously observed during spudcan penetrations in stiff-over-soft clay soils. The method of producing the holes, whether through drilling, coring or water jetting, was also investigated. Results show that punch-through can be mitigated when the layered deposit is punctured in a zone immediately outside the spudcan periphery. [Copyright &y& Elsevier]

Abstract: In many situations, MSW components are processed and shredded before use in laboratory experiments using conventional soil testing apparatus. However, shredding MSW material may affect the target property to be measured. The objective of this study is to contribute to the understanding of the effect of shredding of MSW on the measured compressibility and strength properties. It is hypothesized that measured properties can be correlated to an R-value, the ratio of waste particle size to apparatus size. Results from oedometer tests, conducted on 63.5mm, 100mm, 200mm diameter apparatus, indicated the dependency of the compressibility parameters on R-value. The compressibility parameters are similar for the same R-value even though the apparatus size varies. The results using same apparatus size with variable R-values indicated that shredding of MSW mainly affects initial compression. Creep and biological strain rate of the tested MSW are not significantly affected by R-value. The shear strength is affected by shredding as the light-weight reinforcing materials are shredded into smaller pieces during specimen preparation. For example, the measured friction angles are 32° and 27° for maximum particle sizes of 50mm and 25mm, respectively. The larger MSW components in the specimen provide better reinforcing contribution. This conclusion is however dependent on comparing specimen at the same level of degradation since shear strength is also a function of extent of degradation. [Copyright &y& Elsevier]

In cellular systems, maintaining data rate at the cell edge has been a challenging task due to strong co‐channel interference from neighbouring cells. Several techniques have been proposed to tackle the issue, among which soft frequency reuse (SFR) is the most widely used. A novel multi‐layer SFR scheme combined with cell sectoring is proposed to improve the performance in cell‐edge region. Then, a spectrum allocation scheme in a three‐cell reuse system is designed to ensure the maximisation of the efficiency. A generic expression for power allocation in different regions along with the signal‐to‐noise ratio of multi‐layer SFR in sectored cell is derived. Finally, system‐level simulation has been carried out to demonstrate the efficiency of the proposed resource allocation scheme. It is shown that the spectral efficiency at cell‐edge area improves by ∼10% which is significant for the cell‐edge region. [ABSTRACT FROM AUTHOR]

This paper reports the behaviour of caisson anchors under vertical-horizontal (V-H) loadings in medium dense to dense sand. The three dimensional finite element (3D-FE) analyses are carried out using a modified Mohr-Coulomb (MMC) soil model to capture the stress dependent hardening – softening behaviour of sands. The results are validated against centrifuge test data prior to undertaking a detailed parametric study, exploring the relevant range of parameters in terms of caisson aspect ratio, padeye location, mooring angle at the padeye and sand relative density. It is found that the caisson anchor failure is governed by the sand relative density, mooring angle and the normalised padeye position. The padeye position not only affects the anchor capacity, but also influences the rotation angle of the caisson at failure. An optimal padeye position inducing minimal rotation at caisson failure is found to lie within the range of 0.6-0.7L, where L is the caisson length. To assess capacity under inclined loading, normalised failure envelopes are presented in the V-H space. A design framework is established to estimate the optimal padeye location and caisson capacity for sands with strain hardening – strain softening characteristics. [ABSTRACT FROM AUTHOR]

Abstract: Vanadium-doped ZnTe films of composition 0 to 10wt%V, were prepared onto glass substrate by e-beam evaporation of the element in vacuum at ∼8×10−4 Pa. The effects of various deposition conditions on the electrical properties of the films have been studied in detail. The deposition rate of the ZnTe films was at about 2.05nms−1. X-ray diffraction (XRD) study shows that the as-deposited ZnTe films are amorphous in nature. The effects of temperature on the electrical properties of the ZnTe and ZnTe:V films were studied in details. The heating and cooling cycles of the samples are reversible in the investigated temperature range after successive heat treatments in air. Thickness dependence of electrical conductivity is well in conformity with the Fuchs–Sondheimer theory. Temperature dependence of electrical conductivity shows a semiconducting behavior with a spectrum of activation energy. The value of activation energy for undoped ZnTe films do agree well with earlier reported values. Dopant vanadium concentration increases the conductivity of the samples. The composition and thickness dependence of the activation energy as well as thermoelectric power studies were done in the 300–413K temperature range. The results of d.c. conductivity and thermopower obey an activated conduction mechanism. The thermopower of undoped ZnTe films indicates a p-type conductivity. Thermopower results of ZnTe:V films also suggest that the simultaneous bipolar conduction of both carriers take place. [Copyright &y& Elsevier]

Open reading frame 89 (ORF89) is one of the three genes that are believed to be involved in the latent infection of white spot syndrome virus (WSSV). Here, we report the structure and functional characterization of ORF89. cDNA sequencing, 5′ RLM-RACE, and 3′ RLM-RACE showed that ORF89 gene is transcribed into an unspliced mRNA of 4436 nucleotides, which is predicted to encode a protein of 1437 amino acids. ORF89 expressed an approximately 165-kDa protein in Sf9 cells that localized in the nucleus. Amino acids 678–683 were found to be essential for nuclear localization. Cotransfection assays demonstrated that ORF89 protein repressed its own promoter as well as those of a protein kinase and the thymidine–thymidylate kinase genes of WSSV. SYBR Green real-time PCR indicated that the repression occurred at the transcriptional level. [Copyright &y& Elsevier]