An Overview of Aquaponic Systems: Hydroponic Components

Aquaponics is the union of hydroponics (growing plants without soil) and aquaculture (farming fish or other aquatic organisms) for a fast, efficient method of producing both plant and fish crops. Fish waste from the aquaculture portion of the system, is broken down by bacteria into dissolved nutrients (e.g., nitrogen and phosphorus compounds) that plants utilize to grow in a hydroponic unit. This nutrient removal not only improves water quality for the fish but also decreases overall water consumption by limiting the amount released as effluent

An Overview of Aquaponic Systems: Aquaculture Components

Aquaponics is an integrated production operation that encompasses recirculating aquaculture systems and hydroponics to produce fish and plants in a closed-loop system that mimics the ecology of nature. Simply said, the fish produce nutrient-rich effluent that fertilizes the plants, and the plants filter the water for the fish. Fish waste from the aquaculture portion of the system is broken down by bacteria into dissolved nutrients that plants then utilize to grow in the hydroponic component. This nutrient removal not only improves water quality for the fish but also decreases overall water consumption by limiting the amount released as effluent. The synergistic relationship of the fish and plants has created a popular perception of sustainability around aquaponics by the general public. Additionally, aquaponics can be scaled from a bench-top hobby unit to multi-acre commercial production facilities

Influence of UV Treatment on the Food Safety Status of a Model Aquaponic System

Few microbial studies in aquaponics, a growing trend in food production, have been conducted to determine food safety status. The aim of this study was to determine the food safety status and the effectiveness of ultraviolet treatment (15 W, luminous flux of 900 lm) as a food safety intervention in reducing the microbial loads of the water system in a model aquaponic unit growing lettuce, basil, and barramundi (Australian Sea Bass). Sweet basil, bibb lettuce, water samples, and fish swabs were collected throughout the 118-day production period, and microbial analysis was conducted in triplicate for the presence of E. coli O157:H7, Salmonella spp., and the prevalence of aerobic plate counts (APC), coliforms, and fecal coliforms in these systems. Absence of foodborne pathogens was confirmed using ELISA technology and enumeration through petrifilms (coliform/E. coli). A significant increase was observed in aerobic plate counts over the trial period (1 to 3 log10 CFU·mL−1) in the presence and absence of UV (p \u3e 0.05). Ultraviolet treatment did not significantly reduce the APC or coliform counts when compared to the control system samples. Future work should focus on improving the unit design, the evaluation of bio-solid filtration, and other food safety interventions

Challenges Experienced by Aquaponic Hobbyists, Producers, and Educators

We used an online survey to document challenges experienced by aquaponic hobbyists (n = 81), producers (n = 117), and educators (n = 75). Responses were distilled into the following categories: 1) operations and management; 2) facilities, location, and system design; 3) knowledge and educational resources; 4) funding; 5) economic viability; 6) plant culture; 7) marketing and distribution; 8) fish culture; 9) human factors; 10) regulations and certifications. Training and research in these areas are needed to advance the aquaponics industry

Investigation of API 8 Round Casing Connection Performance- Part III: Sealability and Torque

The performance of the API LT&C8 Round casing connection is investigated using 7-in.-29-lbift Introduction A 7-in.-29-lb/ft pipe size is used to investigate the performance of the API LT&C 8 Round (8R) casing connection. Part I [1], compared stress results determined from unthreaded and threaded finite element models, test results from strain gages, and hand calculations using strength of material equations. These comparisons showed the finite element modeling to be valid. Part II [2], dealt with the effects of thread tapers and external loads on pin and coupling hoop stresses. It also investigated maximum assembly interference based on an assumed criteria. Part III, is concerned with connection sealability based on the assumption that the contact pressure in the mated surfaces must equal or exceed the fluid pressure being contained. Of particular interest is the effects of thread taper, tension and internal pressure, with tension being the greatest unknown influence on leak tightness. Variations in torque are also investigated from the same forces used to evaluate sealability

GraphCombEx: A Software Tool for Exploration of Combinatorial Optimisation Properties of Large Graphs

We present a prototype of a software tool for exploration of multiple combinatorial optimisation problems in large real-world and synthetic complex networks. Our tool, called GraphCombEx (an acronym of Graph Combinatorial Explorer), provides a unified framework for scalable computation and presentation of high-quality suboptimal solutions and bounds for a number of widely studied combinatorial optimisation problems. Efficient representation and applicability to large-scale graphs and complex networks are particularly considered in its design. The problems currently supported include maximum clique, graph colouring, maximum independent set, minimum vertex clique covering, minimum dominating set, as well as the longest simple cycle problem. Suboptimal solutions and intervals for optimal objective values are estimated using scalable heuristics. The tool is designed with extensibility in mind, with the view of further problems and both new fast and high-performance heuristics to be added in the future. GraphCombEx has already been successfully used as a support tool in a number of recent research studies using combinatorial optimisation to analyse complex networks, indicating its promise as a research software tool

Talented suppliers? Strategic change and innovation in the UK aerospace industry

The 1990s marked the start of extensive re-structuring in the aerospace industry throughout the world. While the ensuing consolidation among prime contractors has been widely researched, the changes affecting the aerospace supply chain have received less attention. This study focuses on the re-structuring taking place within the supply chain of the UK aerospace industry. The findings point to extensive re-structuring. Unlike most earlier studies the lean supply model was found to be a powerful influence, with suppliers moving away from subcontractor status and instead taking on the mantle of ‘talented’ suppliers. While some of the implications of lean supply, in terms of the dynamics of innovation, were not apparent, there were modest signs of increased process innovation on the part of some suppliers

Localisation of Human Papillomavirus 16 E7 Oncoprotein Changes with Cell Confluence

E7 is one of the best studied proteins of human papillomavirus type 16, largely because of its oncogenic potential linked to cervical cancer. Yet the sub-cellular location of E7 remains confounding, even though it has been shown to be able to shuttle between the nucleus and the cytoplasm. Here we show with immunocytochemistry that E7 proteins are located in the nucleus and cytoplasm in sub-confluent cells, but becomes cytoplasmic in confluent cells. The change in E7's location is independent of time in culture, cell division, cell cycle phase or cellular differentiation. Levels of E7 are also increased in confluent cells as determined by Western blotting. Our investigations have also uncovered how different analytical techniques influence the observation of where E7 is localised, highlighting the importance of technical choice in such analysis. Understanding the localisation of E7 will help us to better comprehend the function of E7 on its target proteins