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BamX: Rethinking Deployability in Architecture through Weaving
No full textDeployable gridshells are a class of planar-to-spatial structures that achievea 3D curved geometry by inducing bending on a flat grid of elastic beams. However, theslender nature of these beams often conflicts with the structure’s load-bearing capacity.To address this issue, multiple layers are typically stacked to enhance out-of-planestiffness and prevent stability issues. The primary challenge then lies in deploying suchmulti-layered systems globally, as it requires significant shaping forces for actuation.This paper presents an alternative design approach that involves strategically connect-ing compact-to-volumetric gridshell components using weaving principles to shape athick segmented shell. This innovative approach allows for an incremental construc-tion process based entirely on deployable modules with volumetric configurations thatlocally provide the necessary structural depth for the entire system. To demonstrate thisprinciple, we present the realization of BamX, a research pavilion constructed usingdeployable cylindrical components made from raw bamboo slats. These componentsare interconnected at carefully optimized interlocking woven nodes, resulting in abending-active structural frame that is both strong and exceptionally lightweight. Todetermine the optimal topology and geometry of the pavilion, we employ an integrativecomputational approach that leverages advanced numerical optimization techniques.Our method incorporates a physics-based simulation of the bending and twisting be-havior of the bamboo ribbons. By finding the ideal locations for ribbon crossings, weensure that all external and internal forces are in global equilibrium while minimizingthe mechanical stress experienced by each ribbon. BamX exemplifies how a symbiosisof refined weaving craft and advanced computational modeling enables fascinatingnew opportunities for rethinking deployability in architecture.GC
Assessment of existing structures based on elastic-plastic stress fields - Modelling of critical details and investigation of the in-plane shear transverse bending interaction
No full textIBETO
Towards a pattern language for complex-mode mission concept generation
No full textNew space mission profiles arise from the convergence of reduced launch prices, miniaturization of electronics and the maturation of on-orbit servicing technologies. Additionally, a shift towards challenging Lunar objectives pushes for interconnected and complex-mode missions, and trends towards low-cost, sustainability and autonomy also encourage complex modes. The field of space logistics aims to develop conceptual and computational tools to optimize multi-node material-flow networks. However, existing tools insufficiently address the challenge of generating and comparing mission concepts methodically. Through a comprehensive literature review and a case study, we: (1) establish a need for a design support tool for early-phase complex space mission concept generation; (2) establish the potential of a novel approach using pattern languages; (3) propose and describe a concept for an innovative interdisciplinary tool using the identified methods; (4) verify the proposed support tool concept by replicating the Apollo study results as a proof of concept. We created a pattern language in which words are mission concept of operations elements, the grammar is an assembly algorithm allowing to generate options automatically, and the writing system is intuitively readable diagrams illustrating candidate mission modes. Key figures of merit are also automatically compiled. Among the concepts we generated for the Apollo proof of concept study, the four principal candidates considered in 1962 were captured and ranked in the same order as historically and in recent literature. Findings are consistent with Apollo's choice of designing two modules to be separated in Lunar orbit, thus confirming the proposed tool's potential. Decision-makers could be supported in the early stages of the mission design process, where most of the value is locked in, by complementing existing methods such as concurrent engineering. Efficiently designing complex-mode missions is key to enabling cost-effective and highly ambitious missions, therefore supporting cislunar economy development
Understanding and Engineering Thermostability in DNA Ligase from Thermococcus sp 1519
No full textThe physical chemical principles underlying,enzymatic thermostability are keys to understand the way evolution has shaped proteins,to adapt to a broad range of temperatures. Understanding the molecular determinants at the basis of protein thermostability is also important factor for engineering more thermoresistant enzymes to he used in the industrial-setting, such as, for instance, DNA, ligases, Which are important for DNA replication and repair and have been long used in molecular biology and biotechnology. Here, We fitst address the origin of thermostability in the thermophilic DNA ligase from archaeon Thermococcus sp. 1519 and identify thermosensitive regions using molecular modeling and simulations. In addition, we predict mutations that can enhance. thermostability of the enzyme through bioinformatics, analyses. We show that thermosensitive regions of this enzyme are stabilized at higher temperatures by optimization of charged groups on the surface, and we predict that thermostability can be further increased by further optimization of the network among these charged groups. Engineering this DNA ligase by introducing selected mutations (i.e., A287K, G304D, S364I, and A387K) eventually produced a significant and additive increase in the half-life of the enzyme when compared to that of the wild type.UPDALP
Methane formation and future extraction in Lake Kivu
No full textThis chapter summarises the current knowledge on the vertical distribution of methane (CH4) and its formation in Lake Kivu. Additionally, we review the objectives and restrictions under consideration for sustainable extraction (safe, environmentally acceptable, and economically effective) of the enormous amount of CH4 from the lake. The harvested CH4 will be used to produce electricity which is desperately needed in both neighbouring countries: the Democratic Republic of the Congo and Rwanda. From a system-analysis point of view, the following processes need to be included as the minimum for adequately evaluating the vertical and temporal development of the lake CH4 during extraction: (1) in situ CH4 formation occurring in the permanently stratified, anoxic deep-water, (2) CH4 oxidation in the oxic surface water, (3) natural lake-water upwelling caused by subaquatic springs, (4) artificial lake-water up- and downwelling due to extraction- and reinjection-related flows, and (5) upward diffusion caused by double diffusive convection and weak turbulence. Water density is parameterised as a function of temperature, salinity, and the two gases carbon dioxide and CH4. For the sake of clarity of the presentation, we use a simplified 4-box analysis and are neglecting the diffusion process (5). This allows for the essence of the CH4 extraction challenge to be conveyed while avoiding excessive complexities. The system analysis for different CH4 extraction concepts clearly reveals that the depth of reinjection of the CH4-depleted deep-water is critical for the sustainability of the extraction and an optimal CH4 harvesting plan. Here, the suitability of different reinjection scenarios is compared by evaluating each of them in terms of the objectives "safety" (water column stability), "lake ecological integrity" (nutrient upward fluxes), and "economic viability" (amount of harvestable CH4). Comparison of model simulations, run over 50 years, revealed that (1) using lake surface (dilution) water for adjusting the density of the reinjection water and (2) reinjecting the nutrient-rich deep-water in the top 190 m are both unacceptable in terms of sustainability.APHYS0691
Electron relaxation by LO phonons in quantum wires: An adiabatic approach
No full textThe electron states of weakly-one-dimensional quantum wires are computed using the adiabatic approximation in the framework of the k . p theory and the envelope-function approximation. The computed transition rates of electrons from one confined state to any other, mediated by the longitudinal optical (LO) phonons, are clearly ordered with respect to the quantum numbers of the states provided by the adiabatic approximation. The average single electron relaxation time from an excited level is shown to either increase or surprisingly decrease as a function of initial energy. Finally, the relaxation dynamics of an excited population of electrons is analyzed. We show that a fast phenomenological intrasubband thermalization, simultaneous to the LO phonon-mediated relaxation, lowers the final average energy and may in some cases significantly speed up the whole relaxation.LOEQSwiss fed inst technol,dept phys,inst micro & optoelect,ch-1015 lausanne,switzerland. tech univ munich,walter schottky inst,d-85748 garching,germany. Amman, C, UNIV LAUSANNE,INST THEORET PHYS,CH-1015 LAUSANNE,SWITZERLAND.ISI Document Delivery No.: WF124Cited Reference Count: 48Cited References:AKIYAMA H, 1994, PHYS REV LETT, V72, P924BASTARD G, 1990, WAVE MECH APPL SEMICBASTARD G, 1991, SOLID STATE PHYS, V44, P229BENNETT CR, 1995, J PHYS-CONDENS MAT, V7, P9819BOCKELMANN U, 1990, PHYS REV B, V42, P8947BRIGGS S, 1988, PHYS REV B, V38, P8163BRIGGS S, 1989, PHYS REV B, V40, P12001BRIGGS S, 1991, PHYS REV B, V43, P4785CAMPOS VB, 1992, PHYS REV B, V45, P3898CAMPOS VB, 1992, PHYS REV B, V46, P3849CINGOLANI R, 1991, PHYS REV LETT, V67, P891FERREIRA R, 1989, PHYS REV B, V40, P1074FOREMAN BA, 1995, PHYS REV B, V52, P12260GRUNDMANN M, 1994, SEMICOND SCI TECH S, V9, P1939HAACKE S, 1996, SOLID STATE ELECTRON, V40, P299HARTIG M, UNPUBJIANG W, 1993, J APPL PHYS, V74, P1652JIANG W, 1993, J APPL PHYS, V74, P2097JOVANOVIC D, 1993, PHYS REV B, V42, P11108KAPON E, 1989, PHYS REV LETT, V63, P430KIENER C, 1996, PHYS REV B, V53, R4225KIM KW, 1991, J APPL PHYS, V70, P319KNIPP PA, 1992, PHYS REV B, V45, P9091KNIPP PA, 1995, PHYS REV B, V52, P5923LEBURTON JP, 1984, J APPL PHYS, V56, P2850LEBURTON JP, 1992, PHYS REV B, V45, P11022LEBURTON JP, 1993, J APPL PHYS, V74, P1417MACIEL AC, 1995, APPL PHYS LETT, V66, P3039MICKEVICIUS R, 1995, J APPL PHYS, V77, P5095OBERLI DY, 1995, IL NUOVO CIMENTO D, V17, P1641REN SF, 1991, PHYS REV B, V43, P11857RIDDOCH FA, 1984, SURF SCI, V142, P260ROSSI F, 1993, PHYS REV B, V47, P1695ROTA L, 1993, PHYS REV B, V47, P1632ROTA L, 1994, EUROPHYS LETT, V28, P277ROTA L, 1995, PHYS REV B, V52, P5183SAKAKI H, 1980, JPN J APPL PHYS, V19, L735SAKAKI H, 1992, SURF SCI, V267, P623SENNA JR, 1993, PHYS REV B, V48, P4552STROSCIO MA, 1989, PHYS REV B, V40, P6428STROSCIO MA, 1991, PHYS REV B, V42, P1488TATHAM MC, 1989, PHYS REV LETT, V63, P1637TURNER K, 1995, APPL PHYS LETT, V66, P3188VURGAFTMAN I, 1993, APPL PHYS LETT, V62, P2251VURGAFTMAN I, 1994, PHYS REV B, V50, P14309YAMADA T, 1989, PHYS REV B, V40, P6265YU SG, 1995, PHYS REV B, V51, P4695ZHU BF, 1991, PHYS REV B, V44, P192
Influence of ESAT-6 secretion system 1 (RD1) of Mycobacterium tuberculosis on the interaction between mycobacteria and the host immune system
No full textThe chromosomal locus encoding the early secreted antigenic target, 6 kDa (ESAT-6) secretion system 1 of Mycobacterium tuberculosis, also referred to as "region of difference 1 (RD1)," is absent from Mycobacterium bovis bacillus Calmette-Guerin (BCG). In this study, using low-dose aerosol infection in mice, we demonstrate that BCG complemented with RD1 (BCG::RD1) displays markedly increased virulence which albeit does not attain that of M. tuberculosis H37Rv. Nevertheless, phenotypic and functional analyses of immune cells at the site of infection show that the capacity of BCG::RD1 to initiate recruitment/activation of immune cells is comparable to that of fully virulent H37Rv. Indeed, in contrast to the parental BCG, BCG::RD1 mimics H37Rv and induces substantial influx of activated (CD44highCD45RB(-)CD62L(-)) or effector (CD45RB(-)CD27(-)) T cells and of activated CD11c(+)CD11bhigh cells to the lungs of aerosol-infected mice. For the first time, using in vivo analysis of transcriptome of inflammatory cytokines and chemokines of lung interstitial CD11c+ cells, we show that in a low-dose aerosol infection model, BCG::RD1 triggered an activation/inflammation program comparable to that induced by H37Rv while parental BCG, due to its overattenuation, did not initiate the activation program in lung interstitial CD11c+ cells. Thus, products encoded by the ESAT-6 secretion system 1 of M. tuberculosis profoundly modify the interaction between mycobacteria and the host innate and adaptive immune system. These modifications can explain the previously described improved protective capacity of BCG::RD1 vaccine candidate against M. tuberculosis challenge.UPCO
Real-Time ASR from Meetings
No full textThe AMI(DA) system is a meeting room speech recognition system that has been developed and evaluated in the context of the NIST Rich Text (RT) evaluations. Recently, the ``Distant Access'' requirements of the AMIDA project have necessitated that the system operate in real-time. Another more difficult requirement is that the system fit into a live meeting transcription scenario. We describe an infrastructure that has allowed the AMI(DA) system to evolve into one that fulfils these extra requirements. We emphasise the components that address the live and real-time aspects.LIDIA
Efficient ASIC implementation of a real-time depth mapping stereo vision system
No full textThis paper presents a fast and area-efficient implementation of a real-time stereo vision algorithm for spatial depth mapping. The design combines two well-known area-based approaches to stereo thatching and includes an occlusion detection method. Hardware efficiency is achieved by storing only partial images on-chip, avoiding full-sized frame buffers. A low-latency dataflow-oriented structure makes it possible to process 256 x 192 pixel Input streams with a rate In excess of 50 frames per second, amounting to more than 54 million pixel x disparity measurements per second (PDS) (for a 25-pixel disparity range), or roughly 18 GOPS. The design has been Integrated In a 0.25 mu m standard CMOS technology and occupies an area of less than 3 mm(2).TC