Design principles for maximizing photovoltage in metal-oxide-protected water-splitting photoanodes

Metal oxide protection layers for photoanodes may enable the development of large-scale solar fuel and solar chemical synthesis, but the poor photovoltages often reported so far will severely limit their performance. Here we report a novel observation of photovoltage loss associated with a charge extraction barrier imposed by the protection layer, and, by eliminating it, achieve photovoltages as high as 630mV, the maximum reported so far for water-splitting silicon photoanodes. The loss mechanism is systematically probed in metal-insulator-semiconductor Schottky junction cells compared to buried junction p(+) n cells, revealing the need to maintain a characteristic hole density at the semiconductor/insulator interface. A leaky-capacitor model related to the dielectric properties of the protective oxide explains this loss, achieving excellent agreement with the data. From these findings, we formulate design principles for simultaneous optimization of built-in field, interface quality, and hole extraction to maximize the photovoltage of oxide-protected water-splitting anodes.

Analyzing the Effect of Soiling on the Performance of a Photovoltaic System of Different Module Technologies in Kalkbult, South Africa

The fact that most of the large scale solar PV plants are built in arid and semi-arid areas where land availability and solar radiation is high, it is expected the performance of the PV plants in such locations will be affected significantly due to high cell temperature as well as due to soiling. Therefore, it is essential to study how the different PV module technologies will perform in such geographical locations to ensure a consistent and reliable power delivery over the lifetime of the PV power plants. As soiling is strongly dependent on the climatic conditions of a particular location a test station, consisted of about 24 PV modules and a well-equipped weather station, was built within the fences of Scatec’s 75 MW Kalkbult solar PV plant in South Africa. This study was performed to a better understand the effect of soiling by comparing the relative power generation by the cleaned modules to the un-cleaned modules. Such knowledge can enable more quantitative evaluations of the cleaning strategies that are going to be implemented in bigger solar PV power plants. The data collected and recorded from the test station has been analyzed at IFE, Norway using a MatLab script written for this thesis project. This thesis work has been done at IFE, Norway in collaboration with Stellenbosch University in South Africa and Scatec Solar a Norwegian independent power producer company. Generally for the polycrystalline modules it is found that the average temperature corrected efficiency during the period of the experiment has been 15.00±0.08 % and for the thin film-CdTe with ARC is 11.52% and for the thin film without ARC is about 11.13% with standard uncertainty of ±0.01 %. Besides, by comparing the initial relative average efficiency of the polycrystalline-Si modules when all the modules have been cleaned for the first time and the final relative efficiency; after the last cleaning schedule which is when all the reference modules E, F, G, and H have been cleaned for the last time it is found that poly3 performs 2 % and 3 % better than poly1 and poly16 respectively, poly13 performs 1 % better than poly15 as well as poly5 and poly12 performs 1 % and 2 % better than poly10 respectively. Besides, poly5 and poly12 performs a 9 % and 11 % better than poly7. Furthermore, there is no change in performance between poly6 and poly9 as well as poly4 and poly15. However, the increase in performance of poly3 to poly1, poly13 to poly15 as well as poly5 and poly12 to poly10 is insignificant. In addition, it is found that TF22 perform 7% better than the reference un-cleaned module TF24 and similarly; TF21 performs 7% higher than TF23. Furthermore, modules with ARC glass (TF17, TF18, TF19, and TF20) shows that cleaning the modules with only distilled water (TF19) or dry-cleaned after cleaned with distilled water(TF20) decreases the performance of the modules by 5 % and 4 % comparing to its respective reference uncleanedmodules TF17 and TF18 respectively.

Establishment of antibody panels and histochemical techniques in routine tumor diagnosis in Veterinary Pathology

In Portugal, Veterinary Pathology is developing rapidly, and in recent years we assist to the emergence of private laboratories and the restructuring of universities,polytechnics and public laboratories.The Portuguese Society of Animal Pathology,through its actions and its associates has been keeping the discussion among its peers in order to standardizethe criteria of description,classification and evaluation of cases which are the subject of our daily work.One of the last challenges is associated with the use of routine histochemical techniques and immunohistochemistry, in an effort to establish standardized panels for tumour diagnosis, which could eventually reduce each analysis cost.For this purpose a simple survey was built, in which all collaborators answered questions about the markers used for carcinoma, sarcoma and round cell tumour diagnosis, as well as general questions related with the subject. We obtained twenty-one answered to the questions, from public and private laboratories.In general, in most cases immunohistochemical and histochemical methods are used for diagnosis.The wide spectrum cytokeratins are universally used to confirm carcinoma, and vimentin for sarcoma. The CD3 marker is used by all laboratories to identify T lymphocytes. For the diagnosis of B-cell lymphoma, the marker used is not consensual. In each laboratory there are different markers for more specific situations and only two labs perform PCR techniques for diagnosis. These data will be presented to promote extended discussion,namely to reach a consensus when different markers are used.

Subjective Aspects of People with Chronic Ulcers: a Qualitative Study in Brazil and Portugal

Introduction: The experience built in the process of living with chronic ulcer is marked by changes such as the inability to work, to relate socially and causes the need to adapt to a routine care. Understanding this network of meanings is important to develop techniques of individual or collective care. Objective: To understand impregnated subjectivities in the everyday experiences of Brazilian and Portuguese patients with chronic ulcers, in the light of the Oral History of life. Method: Comparative study with a qualitative approach, using Oral History as method and technique. The network of collaborators, formed by males and females, aged 39-82 years, was structured into two groups, one consisting of 06 people in Natal/RN, Brazil and another composed of 10 people in Évora/Portugal. In both groups, the narratives were collected through open questions, which were recorded, transcribed and analyzed by the technique of thematic content analysis. Results: Through the analysis, three themes were revealed: Social repercussion in Brazil and in Portugal; Trajectory of theinjured person; and Coping mechanisms. Conclusion: Changes were observed in social life, leading contributors to isolation, in addition to confronting the stigma experienced. There were also identified points as the reinterpretation of chronic wound carrier about their disease and coping strategies of their chroniccondition.

Using coloured petri nets to simulate DoS-resistant protocols

In this work, we examine unbalanced computation between an initiator and a responder that leads to resource exhaustion attacks in key exchange protocols. We construct models for two cryp-tographic protocols; one is the well-known Internet protocol named Secure Socket Layer (SSL) protocol, and the other one is the Host Identity Protocol (HIP) which has built-in DoS-resistant mechanisms. To examine such protocols, we develop a formal framework based on Timed Coloured Petri Nets (Timed CPNs) and use a simulation approach provided in CPN Tools to achieve a formal analysis. By adopting the key idea of Meadows' cost-based framework and re¯ning the de¯nition of operational costs during the protocol execution, our simulation provides an accurate cost estimate of protocol execution compar- ing among principals, as well as the percentage of successful connections from legitimate users, under four di®erent strategies of DoS attack.

Wet potential

Water is so fundamental to everything that it is almost impossible to meaningfully conceptualise it, which is why it forms the basis of pretty much everything. To suggest that landscape architecture has some sort of privilege with it would be deluded. But, as alchemists of “the world”, we are both expected to deal with it professionally, as well as being forced to do so practically in making anything real, built in that same “world”. When people use words too much, that is the signifiers of things in sound, they become a kind of conceptual short hand to what they are referring to. You can hear this short hand when they use the word, as it gets grammatically dealt with differently – it becomes a conceptual object – a different type of noun. Water is one of these words, and as a supervisor I have almost universally seen students refer to it like this, by the end of their projects, and then have to force themselves to reconsider what it was about water that made them interested in water in the first place. This process is a transition of ideas and technology and technique, and will be the subject of this essay, tracking students responses to the weird substance in design subjects I have taught or projects I have supervised at RMIT since 1997, to and from and then again back to the qualities and issues of water for people generally, and landscape architecture in particular.

Birrarung Marr

Melbourne's new riverside park, Birrarung Marr is located on the north bank of the Yarra, meeting Federation Square at its western end. In design terms it is an important one for both Melbourne and its city centre. It is the first new park in the inner-ring of the city to be built in a hundred years, since Alexandria Gardens, and is also the first major park done by COM since the influential period of designed capital works under the leadership of Rob Adams, at City Projects.

A vision of the past : The Mill Albion

This paper examines The Mill Albion community history project, a diverse, multi-layered public history/art program that captures the social heritage of The Albion Flour Mill, as told through images produced as part of a research consultancy undertaken by QUT for FKP Property Group. The Albion Flour Mill was built in 1930 and continued operations for more than 72 years. After ceasing operation in 2005 the site was left to deteriorate. The FKP Property Group purchased the land to undertake a new urban redevelopment project. This paper reflects on the project and showcases some of the culturally creative ways this community’s history was told, using images.

Incorporating community history into urban redevelopment

A community history project must be relevant to each person within it so that they see themselves as part of the socio-cultural fabric of the area and feel a sense of ownership of their environment. The Mill Albion community history project is a diverse, multi-layered public history/art program that captures the social heritage of The Mill Albion and allows the community to contribute to their ongoing history. The Albion Flour Mill was built in 1930 at a time when Australia was feeling the effects of its worst economic depression and continued operations for more than 72 years. After ceasing operation in 2005 the site was left to deteriorate. The FKP Property Group purchased the land to undertake a new urban redevelopment project, drawing on the design principles of a traditional ‘village’, while valuing the importance of remembering the community that once included the Flour Mill. This paper reflects on the this project and showcases some of the culturally creative ways this community’s history was told, using methods such as digital stories, contemporary and historical photography and oral history.

Alternative dispute resolution : are apology and forgiveness simply two sides of the one coin?

Alternative dispute resolution (a.d.r.) processes are entrenched in western style legal systems. Forms of dispute resolution are utilised within schools and health systems; built in to commercial contracts; found in workplaces, clubs and organisations; and accepted in general day-to-day community disputes. The a.d.r. literature includes references to ‘apology’, but is largely silent on ‘forgiveness’. Where an apology is offered as part of a dispute resolution process, practice suggests that formalised ‘forgiveness’ rarely follows. Mediators may agree there is a meaningful place for apology in dispute resolution processes, but are most unlikely to support a view that forgiveness, as a conscious act, has an equivalent place. Yet, if forgiveness is not limited to the ‘pardoning of an offence’, but includes a ‘giving up of resentment’, or the relinquishing of a grudge, then forgiveness may play an underestimated role in dispute management. In the context of some day-to-day dispute management practice, this paper questions whether forgiveness should follow an apology; and concludes that meaningful resolutions can be reached without any formal element of ‘forgiveness’ or absolution. However, dispute management practitioners need to be aware of the latent role other aspects of forgiveness may play for the disputing parties.

Fixing the city one photo at a time : mobile logging of maintenance requests

We have designed a mobile application that takes advantage of the built-in features of smart phones such as camera and GPS that allow users to take geo-tagged photos while on the move. Urban residents can take pictures of broken street furniture and public property requiring repair, attach a brief description, and submit the information as a maintenance request to the local government organisation of their city. This paper discusses the design approach that led to the application, highlights a built-in mechanism to elicit user feedback, and evaluates the progress to date with user feedback and log statistics. It concludes with an outlook highlighting user requested features and our own design aspirations for moving from a reporting tool to a civic engagement tool.

Retrofitting commercial office buildings for sustainability : tenants’ expectations and experiences

Introduction Buildings, which account for approximately half of all annual energy and greenhouse gas emissions, are an important target area for any strategy addressing climate change. Whilst new commercial buildings increasingly address sustainability considerations, incorporating green technology in the refurbishment process of older buildings is technically, financially and socially challenging. This research explores the expectations and experiences of commercial office building tenants, whose building was under-going green refurbishment. Methodology Semi-structured in-depth interviews with seven residents and neighbours of a large case-study building under-going green refurbishment in Melbourne, Australia. Built in 1979, the 7,008m² ‘B’ grade building consists of 11 upper levels of office accommodation, ground floor retail, and a basement area leased as a licensed restaurant. After refurbishment, which included the installation of chilled water pumps, solar water heating, waterless urinals, insulation, disabled toilets, and automatic dimming lights, it was expected that the environmental performance of the building would move from a non-existent zero ABGR (Australian Building Greenhouse Rating) star rating to 3.5 stars, with a 40% reduction in water consumption and 20% reduction in energy consumption. Interviews were transcribed, with responses analysed using a thematic approach, identifying categories, themes and patterns. Results Commercial property tenants are on a journey to sustainability - they are interested and willing to engage in discussions about sustainability initiatives, but the process, costs and benefits need to be clear. Critically, whilst sustainability was an essential and non-negotiable criterion in building selection for government and larger corporate tenants, sustainability was not yet a core business value for smaller organisations – whilst they could see it as an emerging issue, they wanted detailed cost-benefit analyses, pay-back calculations of proposed technologies and, ideally, wished they could trial the technology first-hand in some way. Although extremely interested in learning more, most participants reported relatively minimal knowledge of specific sustainability features, designs or products. In discussions about different sustainable technologies (e.g., waterless urinals, green-rated carpets), participants frequently commented that they knew little about the technology, had not heard of it or were not sure exactly how it worked. Whilst participants viewed sustainable commercial buildings as the future, they had varied expectations about the fate of existing older buildings – most felt that they would have to be retrofitted at some point to meet market expectations and predicted the emergence of a ‘non-sustainability discount’ for residing in a building without sustainable features. Discussion This research offers a beginning point for understanding the difficulty of integrating green technology in older commercial buildings. Tenants currently have limited understandings of technology and potential building performance outcomes, which ultimately could impede the implementation of sustainable initiatives in older buildings. Whilst the commercial property market is interested in learning about sustainability in the built environment, the findings highlight the importance of developing a strong business case, communication and transition plan for implementing sustainability retrofits in existing commercial buildings.

Estimation and control for an open-source quadcopter

This paper describes modelling, estimation and control of the horizontal translational motion of an open-source and cost effective quadcopter — the MikroKopter. We determine the dynamics of its roll and pitch attitude controller, system latencies, and the units associated with the values exchanged with the vehicle over its serial port. Using this we create a horizontal-plane velocity estimator that uses data from the built-in inertial sensors and an onboard laser scanner, and implement translational control using a nested control loop architecture. We present experimental results for the model and estimator, as well as closed-loop positioning.

Communications and learning structures that facilitate transfer of knowledge at innovation transition points

Innovation processes are rarely smooth and disruptions often occur at transition points were one knowledge domain passes the technology on to another domain. At these transition points communication is a key component in assisting the smooth hand over of technologies. However for smooth transitions to occur we argue that appropriate structures have to be in place and boundary spanning activities need to be facilitated. This paper presents three case studies of innovation processes and the findings support the view that structures and boundary spanning are essential for smooth transitions. We have explained the need to pass primary responsibility between agents to successfully bring an innovation to market. We have also shown the need to combine knowledge through effective communication so that absorptive capacity is built in process throughout the organisation rather than in one or two key individuals.

The scalability and the strategy for EMR database encryption techniques

EMR (Electronic Medical Record) is an emerging technology that is highly-blended between non-IT and IT area. One methodology is to link the non-IT and IT area is to construct databases. Nowadays, it supports before and after-treatment for patients and should satisfy all stakeholders such as practitioners, nurses, researchers, administrators and financial departments and so on. In accordance with the database maintenance, DAS (Data as Service) model is one solution for outsourcing. However, there are some scalability and strategy issues when we need to plan to use DAS model properly. We constructed three kinds of databases such as plan-text, MS built-in encryption which is in-house model and custom AES (Advanced Encryption Standard) - DAS model scaling from 5K to 2560K records. To perform custom AES-DAS better, we also devised Bucket Index using Bloom Filter. The simulation showed the response times arithmetically increased in the beginning but after a certain threshold, exponentially increased in the end. In conclusion, if the database model is close to in-house model, then vendor technology is a good way to perform and get query response times in a consistent manner. If the model is DAS model, it is easy to outsource the database, however, some techniques like Bucket Index enhances its utilization. To get faster query response times, designing database such as consideration of the field type is also important. This study suggests cloud computing would be a next DAS model to satisfy the scalability and the security issues.