Holographic optical interconnects in dichromated gelatin

Abstract unavailable please refer to PD

The Strict-Sense Nonblocking Multirate l

This paper considers the nonblocking conditions for a multirate logd(N,0,p) switching network at the connection level. The necessary and sufficient conditions for the discrete bandwidth model, as well as sufficient and, in particular cases, also necessary conditions for the continuous bandwidth model, were given. The results given for dn-1/2f0≥f1+1 in the discrete bandwidth model are the same as those proposed by Hwang et al. (2005); however, in this paper, these results were extended to other values of f0, f1, and d. In the continuous bandwidth model for B+b>1, the results given in this paper are also the same as those by Hwang et al. (2005); however, for B+b≤1, it was proved that a smaller number of vertically stacked logdN switching networks are needed

Optical Switching for Scalable Data Centre Networks

This thesis explores the use of wavelength tuneable transmitters and control systems within the context of scalable, optically switched data centre networks. Modern data centres require innovative networking solutions to meet their growing power, bandwidth, and scalability requirements. Wavelength routed optical burst switching (WROBS) can meet these demands by applying agile wavelength tuneable transmitters at the edge of a passive network fabric. Through experimental investigation of an example WROBS network, the transmitter is shown to determine system performance, and must support ultra-fast switching as well as power efficient transmission. This thesis describes an intelligent optical transmitter capable of wideband sub-nanosecond wavelength switching and low-loss modulation. A regression optimiser is introduced that applies frequency-domain feedback to automatically enable fast tuneable laser reconfiguration. Through simulation and experiment, the optimised laser is shown to support 122×50 GHz channels, switching in less than 10 ns. The laser is deployed as a component within a new wavelength tuneable source (WTS) composed of two time-interleaved tuneable lasers and two semiconductor optical amplifiers. Switching over 6.05 THz is demonstrated, with stable switch times of 547 ps, a record result. The WTS scales well in terms of chip-space and bandwidth, constituting the first demonstration of scalable, sub-nanosecond optical switching. The power efficiency of the intelligent optical transmitter is further improved by introduction of a novel low-loss split-carrier modulator. The design is evaluated using 112 Gb/s/λ intensity modulated, direct-detection signals and a single-ended photodiode receiver. The split-carrier transmitter is shown to achieve hard decision forward error correction ready performance after 2 km of transmission using a laser output power of just 0 dBm; a 5.2 dB improvement over the conventional transmitter. The results achieved in the course of this research allow for ultra-fast, wideband, intelligent optical transmitters that can be applied in the design of all-optical data centres for power efficient, scalable networking

Industrial and Technological Transitions:The Case of CPV

Projecte final de carrera fet en col.laboració amb el centre Chalmers Tekniska HögskolaEnergy moves the World. Electricity demand and consumption keeps growing year by year to cover the needs for a wealthy development of all the countries. Nowadays, most of the energy is produced by means of fossil fuels, which entail a set of negative externalities such as their generated pollution and related health problems, the risk of global warming by the growing release of greenhouse gases and energy security provided by the unstable situation of many countries where raw material fossil fuel reserves is located. Shifting to a model including renewable technologies would help to reduce those externalities, by promoting more ecologically friendly systems and fostering the countries both economically and socially, as many related jobs would be generated and general wealth would be enhanced. Despite these positive effects, changing the model is not an easy issue, since incumbent technologies are currently well established profitable options, benefited by long developing time, compared to the more immature renewable energy options. In all, as stated in the literature (Geels, 2002), the inducement of a regime shift, not only depends on the availability of better technologies, but generally also needs a change in society to be ready to accept the novelties. Hence, making renewable energies competitive towards incumbent is not only matter of offering better technologies, but a critical policy challenge to be implemented long before their massive adoption. An attractive framework to for the analysis of such changes is the definition of a Technological Innovation System (TIS), which describes a number of functions to be set up by main actors, institutions and networks of an area of development in order to achieve its successful deployment. It includes 8 key aspects: the creation of new knowledge, the entrepreneurial experimentation, the materisalisation, the guidance of the direction of search, the supply of resources (such as capital and competencies), the creation of positive external economies, the legitimacy creation and the formation of markets. This framework has already been used to describe the successful deployment of wind industry and the take off of photovoltaics (PV)(Jacobson, 2004). The latter one, PV stands as a very elegant way of generating electricity directly from the sunlight in simple, modular, reliable systems. However, they are strongly constrained by the costs –and despite last years growing relevance, massive adoption is still limited up-to less than 0,2% of global electricity, and highly dependant on subsidies. One of the pathways for cost reduction is by means of optical concentration of the sunlight in smaller active surfaces. The concept is called Concentrating Photovoltaics (CPV) and sacrifices the simplicity of standard PV for the promise of highest performance and lower costs. This master thesis deals with the study of CPV technological option. It is an interesting study case for regime shift, as its evolution already shows several unsuccessful attempts to scale up. First one, in the late 70ies, an energy hungry world challenged by oil crises technologies triggered the research of first prototypes and pilot plants. However, they did not manage to meet expectations to continue the adoption after the crises passed, till the mid 90ies, when a more established PV industry nursed by state policies overtook again this research path, resulting in the Euclides project. Complexity of the system and the lack of well prepared markets to adopt the novelty kept the allocation of new resources away from this risky approach. But the founding from this project served to set up the direction of search, which resulted in the emergence of nowadays systems,based on high efficient multijunction cells, and which are finally able to turn into reality the promise of the highest performances ever reached. With the steady growth of PV opening the window of opportunity of tracked small utilities, combined with the silicon shortage has finally given CPV the necessary attention to attract resources and brought an amount of new entrants with the main aim to take off this technology. Thus, CPV technologies will have to overcome a new set of challenges related to preparation for growth. With a PV industry on the verge of becoming mature (which will happen the day PV costs reaches grid parity), subsidies will shrink as they become unnecessary for some applications. Instead, CPV will still need to lower down costs to bulk power costs, and external economies may not be able yet to provide necessary returns in order to scale up. Last important challenge is the emergence of competing options such as concentrated solar power (CSP) and thin film that could result CPV technologies to be locked out if they do not manage to maintain the learning curve. For all these reasons, this seems to be a critical point for CPV industry deployment

Current Progress in Biopolymer-Based Bionanocomposites and Hybrid Materials

In recent years, the development of biopolymers based on constituents obtained from natural resources has been gaining considerable attention. The utilization of biopolymers to engineer advanced bionanocomposites and hybrid materials is the focus of increasing scientific activity, explained by growing environmental concerns and interest in the novel features and multiple functionalities of these macromolecules.In this Special Issue, we aim to present the current state of the art in research pertaining to biopolymer-based bionanocomposites and hybrid materials, and their advanced applications. Contributions on the processing of biopolymers and bionanocomposites, the use of diverse biopolymer sources such as polysaccharides, the reinforcement of nanosized materials with biopolymers, and applications of these biopolymers, bionanocomposites, and biohybrid materials will constitute the backbone of this Special Issue

Special Libraries, Spring 1994

Volume 85, Issue 2https://scholarworks.sjsu.edu/sla_sl_1994/1001/thumbnail.jp

Forts and Fortification in Wallacea: Archaeological and Ethnohistorical Investigations

This volume presents ground-breaking research on fortified sites in three parts of Wallacea by a highly regarded group of scholars from Australia, Europe, Southeast Asia and the United States. In addition to surveying and dating defensive sites in often remote and difficult terrain, the chapters provide an important and scholarly set of archaeological and ethnohistoric studies that investigate the origin of forts in Wallacea. Socio-political instability from climate events, the materialisation of indigenous belief systems, and the substantial impact of imperial expansion and European colonialism are examined and comprise a significant addition to our knowledge of conflict and warfare in an under-studied part of the Indo-Pacific. The archaeological record for past conflict is frequently ambiguous and the contribution of warfare to social development is mired in debate and paradox. Authors demonstrate that forts and other defensive constructions are costly and complicated structures that, while designed and built to protect a community from a threat of imminent violence, had (and have) complicated life histories as a result of their architectural permanence, strategic locations and traditional cultural and political significance. Understanding why conflict outbreaks – like human colonisation – often appear in the past as a punctuated event can best be approached through long-term records of conflict and violence involving archaeology and allied historical disciplines, as has been successfully done here. The volume is essential reading for archaeologists, cultural heritage managers and those with an interest in conflict studies.' — Professor Geoffrey Clark, College of Asia and the Pacific, The Australian National University, Canberra

Technology 2001: The Second National Technology Transfer Conference and Exposition, volume 2

Proceedings of the workshop are presented. The mission of the conference was to transfer advanced technologies developed by the Federal government, its contractors, and other high-tech organizations to U.S. industries for their use in developing new or improved products and processes. Volume two presents papers on the following topics: materials science, robotics, test and measurement, advanced manufacturing, artificial intelligence, biotechnology, electronics, and software engineering