8,127 research outputs found
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No full textThe real role of active-shell in enhancing the luminescence of lanthanides doped nanomaterials Wu, F.; Liu, X.; Kong, X.; Zhang, Y.; Tu, L.; Liu, K.; Song, S.; Zhang, H
Putaoa huaping Hormiga & Tu, 2008, new species
No full textPutaoa huaping new species (Figs. 1-11) Etymology. The species epithet is a noun in apposition, taken from the type locality. Types. Male holotype, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 850 m, N 25.60338 °, E 109.90554 °, coll. L. Tu, 3 Nov. 2007 (# 1386; Deposited in California Academy of Sciences, San Francisco, CAS). Paratypes: 1 female (same data as holotype, CAS); 1 male, 8 females, Longtangjie Village, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 802 m, N 25.60405 °, E 109.90138 °, coll. K. Liu, 6 Nov. 2007 (# 1372; Deposited in Capital Normal University, Beijing); 1 male, 1 female, Xietangwan Village, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 804 m, N 25.60235 °, E 109.90889 °, coll. K. Liu, 4 Nov. 2007 (# 1354; deposited at Museum of Comparative Zoology, Harvard University); 2 females, Xietangwan Village, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 804 m, N 25.60235 °, E 109.90889 °, coll. K. Liu, 4 Nov. 2007 (# 1354; deposited at American Museum of Natural History, New York). Diagnosis: Males of P. huaping can be most easily distinguished from other pimoid species by a series of extremely large and robust macrosetae on the pedipalpal tibia (Figs. 3 A, 5 B, C, E); these macrosetae are thicker and more numerous than those of its sister species, P. megacanthus. The unique shape of the PEP, highly bifurcated, is also diagnostic (Fig. 3 B, 6 A-C, F). Females of P. huaping are diagnosed by the rather flat epigynum with lateral openings (Figs. 4 A-C). Description. Male (holotype; Figs. 1 A-D; see also genus description). Total length 3.82. Cephalothorax 2.00 long, 1.7 wide, 1.15 high. Sternum 1.03 long, 1.00 wide. Abdomen 2.00 long, 1.68 wide. AME diameter 0.15. Clypeus height 1.48 times one AME diameter. Carapace with deep longitudinal fovea (Figs. 1 A, D). Chelicerae with three prolateral and four retrolateral teeth; stridulatory striae absent (Fig. 8 D). Legs annulated. Femur I 2.33 long, 1.17 times the length of cephalothorax. Metatarsus I trichobothrium 0.25. Metatarsus IV trichobothrium present. Pedipalp as in Figs. 3, 4, 5, 6, 8 A, B. Pedipalpal tibia with one prolateral and two retrolateral trichobothria. Female (paratype, same locality as male; Figs. 2 B, C). Total length 3.92. Cephalothorax 2.00 long, 1.43 wide, 1.13 high. Sternum 1.00 long, 0.93 wide. Abdomen 2.45 long, 1.90 wide. AME diameter 0.16. Clypeus height 1.30 times one AME diameter. Chelicerae with five prolateral and four retrolateral teeth; stridulatory striae absent (Fig. 9 B). Legs annulated. Femur I 2.13 long, 1.07 times the length of cephalothorax. Metatarsus I trichobothrium 0.26. Epigynum as in Figs. 2 D, E, 4 A-C and 8 E, F. Variation. Male cephalothorax length ranges from 1.95 to 2.35 (n = 4). Female cephalothorax length ranges from 1.60 to 2.40 (n = 23). Male total length ranges from 3.70 to 4.25 (n = 4). Female total length ranges from 3.15 to 5.10 (n = 23). Natural History. Putaoa huaping has been collected in native forests in China at altitudes between 700 and 1,000 m. Their webs are horizontal, thin and flat, built on the rock walls found on the side of mountain’s roads, usually covered by mosses. During day time the spiders normally hide under the adjacent mosses. Distribution. Known from the Guangxi province, in south China. Additional specimens studied (all deposited in Capital Normal University, Beijing): 2 females, Mt. Maozhushan, Fuping Station, Huaping National Nature Reserve, Guangxi Prov., alt. 942 m, N 25.60328 °, E 109.95941 °, coll. L. Tu, 30 Oct. 2007 (# 1310); 1 male, 1 female, Square-bamboo Forest, Hongtan Station, Huaping National Nature Reserve, Guangxi Prov., alt. 828 m, N 25.60760 °, E 109.94751 °, coll. L. Tu, 31 Oct. 2007 (# 1314); 2 females, Xiaojialu Village, Hongtan Station, Huaping National Nature Reserve, Guangxi Prov., alt. 936 m, N 25.60931 °, E 109.95181 °, coll. L. Tu, 1 Nov. 2007 (# 1340); 1 male, 1 female, Bijiahe River, Hongtan Station, Huaping National Nature Reserve, Guangxi Prov., alt. 932 m, N 25.60876 °, E 109.94865 °, coll. L. Tu, 1 Nov. 2007 (# 1345); 1 female, Hongmaochong Village, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 688 m, N 25.59757 °, E 109.90448 °, coll. K. Liu, 5 Nov. 2007 (# 1361); 1 male, 6 females, Cathaya argyrophylla Forest, Cujiang Station, Huaping National Nature Reserve, Guangxi Prov., alt. 992 m, N 25.60403 °, E 109.91103 °, coll. K. Liu, 7 Nov. 2007 (# 1382).Published as part of Hormiga, Gustavo & Tu, Lihong, 2008, On Putaoa, a new genus of the spider family Pimoidae (Araneae) from China, with a cladistic test of its monophyly and phylogenetic placement, pp. 1-21 in Zootaxa 1792 on pages 5-11, DOI: 10.5281/zenodo.18254
Landscape Architecture at TU Delft 1973-2011: Ter gelegenheid afscheid Prof. Dr. Clemens Steenbergen
No full textHet is haast onmogelijk om de werkzame jaren van Prof. Dr. Clemens Steenbergen hier op de TU Delft in het kort samen te vatten. Dit is een persoonlijk boek van collega's, medewerkers en studenten ter gelegenheid van zijn afscheid op 15. December 2011.UrbanismArchitectur
Periodic structures for melting enhancement: observation of critical cell size and localized melting
No full textThe use of metallic periodic structures was considered for melting rate enhancement of a phase change material (PCM) contained in a rectangular enclosure isothermally heated from the side. The critical (optimized) cell size, or pore size, of a periodic structure with fixed porosity, realising the shortest melting time by maximizing the convection and conduction heat transfer rate into the PCM, was studied. Furthermore, the effects of material properties (copper, aluminium, nickel, and stainless steel), enclosure length, wall-melting temperature difference and porosity were numerically investigated. It was observed that increasing porosity and/or reducing thermal conductivity enlarged the critical cell size (i.e. the optimal cell size that minimizes the melting time). The critical PPIs (pores per inch) of copper and aluminium periodic structures for all studied porosities were 10; for nickel, the critical values were 10 PPIs for porosity values of 0.75, 0.8 and 0.85 while it reduces to 5 PPI for the highest porosity considered here being 0.95. Interestingly, showing a different trend, the critical PPI of stainless-steel structures was 5 for the lowest porosity (0.75) and reduced to 3 for higher porosities. The results clearly demonstrated localised melting which was observed in all periodic structures except for the 10 PPI stainless-steel case. Scattered melting islands are observed as opposed to a moving interface when ϕ=(dp/L)αligament/αPCM>1. For such cases, localized melting occurs and the PCM is melted at the ligaments away from the heated wall before the melt front reaches those ligaments.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Process and Energ
Characterization of a novel bacterial PAMP - elongation factor Tu - and its role in "Arabidopsis thaliana" defense and immunity
No full textThe discrimination of self and nonself is a primary challenge for all living organisms to detect microbial invasion and to protect and defend against the invader. If a pathogen manages to overcome constitutive barriers, highly specific recognition systems are able to identify common pathogenic signals and activate the innate immune system as a first line of defense. Specialized cells and a circulatory system that is able to spread somatically generated adaptive immune responses to the infection side exist only in animals. Plants lack an adaptive immune system comparable like this, but they independently co-evolved the capability to detect microbial invasions by perception of specific molecules, so called PAMPs (pathogen associated molecular patterns), and subsequent activation of innate immune responses. Flagellin, the major subunit of the bacterial motility organ flagellum (Yonekura, K. et al. 2001), can be regarded as the best characterized bacterial PAMP in plants. Flg22, a synthetic peptide comprising the highly conserved epitope of the flagellin Nterminus, is recognized by the plant cell and is sufficient to activate innate immune responses. In this work based on the model plant Arabidopsis thaliana, experiments with bacterial extracts devoid of elicitor active flagellin, show still the capability to induce a broad set of plant defense reactions as flagellin, suggesting that at least one additional perception system for another elicitor exist. This novel elicitor and the corresponding active site were identified as the first 18-26 amino acids from the Nterminus of bacterial Elongation factor Tu (elf18-elf26). This essential protein, involved in the delivery of aminoacyl-tRNA to the ribosome during the translation process, is highly conserved over all organisms (Appendix 1) and is the most abundant protein in the bacterial cell (Helms, M. K. and Jameson, D. M. 1995). Furthermore it is considered to be the slowest evolving protein (Gaucher, E. A. et al. 2003) containing all characteristics for a classical PAMP (see definition included in General Introduction). Further characterization of the EF-Tu/Arabidopsis thaliana interaction showed that all known plant defense mechanisms are activated upon EFTu elicitation. This includes extra cellular medium alkalinization of suspension cultured cells of Arabidopsis, production of reactive oxygen species (ROS) (Laloi, C. et al. 2004) and increase in the biosynthesis of plant hormone ethylene. Like shown previously for flagellin (Zipfel, C. et al. 2004), pre-treatment of Arabidopsis with elf-peptides led to enhanced resistance against plant pathogenic bacteria Pseudomonas
syringae pv. tomato (DC3000). Gene expression changes were analyzed using
Affymetrix ATH1 array and about 1000 genes with induced expression after 30-60
minutes treatment with elf-peptides were identified. These genes were congruent with
that affected by flg22 treatment (Navarro, L. et al. 2004, Zipfel, C. et al. 2004). The
same genes were also found to be induced in the flagellin insensitive receptor mutant
fls2 upon elf-treatment. Binding studies with radio labeled elf26-125I-TY show that
there is a high affinity binding site for EF-Tu existing in Arabidopsis thaliana, which is
saturable, highly specific and independent of FLS2. Crosslinking experiments
identified a polypeptide band of 150 kDa as potential binding site for EF-Tu. Strikingly
the perception of one PAMP (e.g. flg22) leads to a higher amount of binding sites for
the other elicitor (e.g. elf18). Furthermore the perception of EF-Tu activates, like
flg22, a MAP kinase-based signaling cascade in nearly identical kinetic. Together this
study indicate two independent receptors using a converging signaling cascade that
leads to the activation of the plant innate immune system with the same broad array
of plant defense reactions
Direct Evidence of Relaxation Anisotropy Resolved by High Pressure in a Rigid and Planar Glass Former
No full textRigid molecular glass-formers with no internal degrees of freedom nonetheless have a single secondary Î2-relaxation. For a rigid and planar molecule, 1-methylindole (1MID), although a secondary relaxation is resolved at ambient pressure, its properties do not conform to the rules established for rigid molecules reported in early studies. By applying pressure to the dielectric spectra of 1MID, we find the single secondary relaxation splits into two. The slower one is pressure sensitive showing connections to the α-relaxation as observed in other rigid molecules, while the faster one is almost pressure insensitive and dominate the loss at ambient pressure. The two secondary relaxations, identified to associate with the out-of-plane and in-plane rotations of the rigid and planar 1MID, are resolved and observed for the first time by increasing density via elevating pressure
Tabu-Based Large Neighbourhood Search for Time-Dependent Multi-Orbit Agile Satellite Scheduling
No full textAgile Earth observation satellite (AEOS) scheduling is complex, due to long visible time windows and time-dependent transitions between observations. We introduce a generic approach suited for scheduling problems characterised by time-dependency and/or sequence-dependency. Our approach is a novel hybridization of adaptive large neighbourhood search (ALNS) and tabu search. We further introduce partial sequence dominance and insertion position ordering operators to the ALNS. Extensive computational results on a real-world multi-orbit AEOS observation scheduling benchmark show that the hybrid ALNS robustly outperforms an improved mixed integer programming model and two recent state-of-the-art metaheuristic methods. The proposed method increases solution quality by more than 10% and reduces calculation time by more than 70% on averageGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Algorithmic
Clustering of chiral particles in flows with broken parity invariance
No full textThe dynamics of small particles suspended in turbulent flows is an important problem in Nature and in Science. Previous work has mainly focused on the motion of spherical particles, while less is known about particles with asymmetric shapes. We study particles which break parity invariance (chiral particles). Particles of different chirality may respond differently to the structures of the flow. Helicoidal-like structures in the flow affect the particles differently depending on the parity of the helicoid as well as on the chirality of the particle. For flows where one of the two parities of the helicoidal-like structures is more common suspended chiral particles experience different levels on clustering depending on their chirality. Using analytical methods and direct numerical simulations we investigate the mechanisms of preferential sampling and clustering of chiral particles in flows with local or global breaking of parity invariance
Surgidero de Batabanó Harbor, Cuba
No full textThe harbor of Surgidero de Batabano is a harbor that lies in the Gulf of Batabano in the South-Western part of Cuba. It serves as a connection between the main land of Cuba and the islands 'Isla de la Juventud' and Cayo Largo. The Batabano harbor suffers from sediment accretion. The accretion of sediment is harmful to port operations, since the depth of the quays and approach channel decreases gradually and ships are no longer able to enter the harbor. Since 1959 maintenance dredging is required every 4 years inside the manoeuvre area of the harbor, along the quay and inside the approach channel, in order to keep the harbor available for shipment. This is a costly operation. The Cuban harbor authority, APN (Autoridad Portuaria Nacional), want this problem to be solved. When considering the problems described above, the goal of this project is defined by the following: 'To reduce the frequency of dredging of accreted sediment in the harbor of Surgidero de Batabano, while keeping in mind costs, future plans, impact on the environment as well as local facilities'. Furthermore it is very important to calculate the amount of sediment accreting in the harbor and its origins. This information is useful when considering the solutions for the problems. During the analysis of the project, the project site has been investigated by literature and a site visit. The boundary conditions have been determined and the technical demand have been specified. The desires of the APN have been taken into account as well. Using all information obtained in the project analysis, the sediment transport processes inducing the accretion of sediment in the harbor have been analysed. Using theory, calculations and computer simulations, it was discovered that a combination of alongshore and cross-shore sediment transport governing the accretion in the harbor: - Alongshore transport of sediment along the coast, mainly from East to West, generated by normal wave conditions from an East/South-East direction. Sediment transported by this alongshore current, will be deposited in between the breakwaters; - Cross-shore transport of sediment perpendicular to the coast, where both sediment from deeper waters as well as accreted alongshore sediment in front of the harbor is transported by normal and extreme conditions. With the source of sediment known, several preliminary designs were created. Using a Multi Criteria Analyses, cost estimation and risk evaluation 4 preliminary designs were selected to be designed in further detail; extension of the existing Eastern breakwater, extension of the Western breakwater, a combination of these two and the current solution (remain dredging every 4 years). The main reasons for selecting these designs are: efficiency against accretion one the one hand and the wishes of the APN on the other hand. In order to obtain an optimal solution, the above mentioned designs were varied in layout. From these 9 layout options the 4 best options were selected as final designs to be further elaborated. These were a Western breakwater (attached and detached), an Eastern breakwater and a combination of a Western- and an Eastern breakwater. Using theory, calculations and computer simulations, the effectiveness against accretion in the harbor was estimated. Every design was evaluated using an Multi Criteria Analyses (MCA). The costs of each design has been determined. Using both costs and the MCA the best design was selected. The design to be recommended, is the combination of an extension of the existing Eastern breakwater and the expansion of the Western breakwater. Though this is not the cheapest option nor the most effective against accretion of sediment, the combination of these factors give the best overall results for a life span of 50 years. Another great advantage of this design, is the fact it can be built in two phases: first the Eastern and last the Western breakwater. In this was APN will be able to spread the costs of the construction of the design over a longer time.Hydraulic EngineeringCivil Engineering and Geoscience
Dissipation of Quasiclassical Turbulence in Superfluid 4He
No full textWe compare the decay of turbulence in superfluid 4He produced by a moving grid to the decay of turbulence in the same channel created by either an impulsive spin-down to rest or by intensive ion injection. In all cases the vortex line density L at late time t decays as L ~ t^-3/2. Below 0.8 K, the spin-down turbulence maintains initial rotation and decays slower than grid turbulence and ion-jet turbulence. This is presumably due to the decoupling of the superfluid component from the normal one at large length scales at low temperatures, thus changing its effective boundary condition from no-slip to slip
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