Stabilization system for camera control on an unmanned surface vehicle

SeaFox is an unmanned surface vehicle (USV) primarily used for maritime security operations. Currently, a remotely operated vision based camera is used to track a particular target whilst the USV approaches the intended target. While the USV is in motion, the hydrodynamic forces and mechanical vibrations makes it difficult for the operator to lock on to the target at all times. This thesis addresses this issue through the development of a self compensated motion controller that uses geo-pointing to track and lock onto a target at all times. The disturbance data as captured by the onboard IMU sensor is used to establish parameters for the compensator. The compensated pan tilt angles are fed to the vision based camera through a PID controller. The controller developed will enable the vision based camera system to autonomously track the intended target independently of the motion of the USV.http://archive.org/details/stabilizationsys109453832Singapore Technologies Kenetics Ltd. author (civilian).Approved for public release; distribution is unlimited

ASSESSMENT OF PRETREATMENT TO MICROFILTRATION FOR DISALINATION IN TERMS OF FOULING INDEX AND MOLECULAR WEIGHT DISTRIBUTION

Abstract In this study, different processes such as flocculation with ferric chloride (FeCl 3 ) and deep bed filtration (sand filtration and dual media filtration) as a pre-treatment to microfiltration (MF) were used for seawater desalination. The performance of these pre-treatments was determined in terms of silt density index (SDI) and modified fouling index (MFI) and flux decline in MF. Flux declin of MF with seawater was 45% without any pre-treatment, 42% after pre-treatment of FeCl 3 flocculation, 24% after pre-treatment of sand filtration with inline coagulation and 22% after pre-treatment of dual media filtration (sand and anthracite), respectively. MFI and SDI also indicated that deep bed filtration with in-line flocculation was better pre-treatment than flocculation alone. Detailed molecular weight distribution (MWD) of seawater organic matter was examined after different pretreatments. MWD of the initial seawater mainly ranged from 1510 Da to 130 Da. Deep bed filtration with in-line flocculation removed relatively large molecular weight of organic matter (1510 -1180 Da), while the small molecular weights (less than 530 Da) were not removed

Integrated Design of a Small Wastewater Treatment Plant - A Case Study from Thailand

This study describes the development of an integrated design framework comprising technical, environmental, social, and economic modules to manage the design of communal wastewater treatment plant. It demonstrates a simple yet effective design management framework developed to tackle the challenges of incorporating Local Agenda 21 and the elements of triple bottom line reporting. The examined alternatives included stabilization pond, aerated lagoon, and biological contact oxidation treatment technologies with 1500 m3/day plant capacity. The integrated process facilitated comprehensive design and ensured the systemic and informed involvement of all relevant stakeholders. Environmental and technical criterion focused on reducing current impact on the aquatic environment in terms of nitrogen, ammonia, biochemical oxygen demand and suspended solids pollutants. Stabilization pond treatment was identified as the most appropriate solution to offer adequate treatment performance, simple and robust operability, and affordable user costs

Using Multipath Priority Routing for Solar Powered Wireless Sensor Networks

Constant growth in the wireless sensor network (WSN) needs routing protocol which can cater for renewable energy sources as compared to conventionally used non-renewable energy sources in sensor nodes. APPOLO algorithm is used to periodically and locally determine the topological knowledge range of each solar-powered node, based on an estimated energy budget for the following period. Energy budget includes current energy, the predicted energy consumption and the energy expected from the solar cell. PISA is a QoS aware routing used for route selection based on objective. Priority based routing in solar powered wireless sensor network is implemented using APOLLO and PISA. Thus energy saving is attained for real-time route discovery. In this paper, multipath non-redundant data dissemination approach is used for the priority based routing scheme to further optimize use of energy in wireless sensor network

Surface Treatment of Polymer Membranes for Effective Biofouling Control

Membrane biofouling is the consequence of the deposition of microorganisms on polymer membrane surfaces. Polymeric membranes have garnered more attention for filtering and purifying water because of their ease of handling, low cost, effortless surface modification, and mechanical, chemical, and thermal properties. The sizes of the pores in the membranes enable micro- and nanofiltration, ultrafiltration, and reverse osmosis. Commonly used polymers for water filter membranes are polyvinyl chloride (PVA), polyvinylidene fluoride (PVDF), polyamide (PA), polyethylene glycol (PEG), polyethersulfone (PES), polyimide (PI), polyacrylonitrile (PAN), polyvinyl alcohol (PA), poly (methacrylic acid) (PMAA), polyaniline nanoparticles (PANI), poly (arylene ether ketone) (PAEK), polyvinylidene fluoride polysulfone (PSF), poly (ether imide) (PEI), etc. However, these polymer membranes are often susceptible to biofouling because of inorganic, organic, and microbial fouling, which deteriorates the membranes and minimizes their lives, and increases operating costs. Biofouling infection on polymer membranes is responsible for many chronic diseases in humans. This contamination cannot be eliminated by periodic pre- or post-treatment processes using biocides and other chemicals. For this reason, it is imperative to modify polymer membranes by surface treatments to enhance their efficiency and longevity. The main objective of this manuscript is to discuss application-oriented approaches to control biofouling on polymer membranes using various surface treatment methods, including nanomaterials and fouling characterizations utilizing advanced microscopy and spectroscopy techniques

Benefits of local government and university research alliances

Local government plays an integral role in the Australian economy with a cumulative annual expenditure of over Aus$20 billion representing around 2% of Australian GDP. Local government authorities employ around 1•3% of the Australian workforce and provide a wide range of services and infrastructure. There is a general lack of appreciation among council staff of the value of collaboration with universities and vice versa. However, staff at Kogarah Municipal Council, having been involved in partnership projects with universities, strongly value the benefits of such collaborations. Councils can provide a ‘one-stop-shop’ for applied research and its application for a range of disciplines from science and technology to arts and policy studies

Application of air flow for mitigation of particle deposition in submerged membrane microfiltration

This study investigates the effect of microfiltration operating conditions on membrane fouling of colloidal particles of kaolin clay. Experiments were conducted with a flat sheet membrane submerged in a suspension prepared from kaolin clay powder of size varying from 0.1 to 4 mm (Sigma) with a mean particle size 2.10 mm. The particle size distribution of clay was unimodal and the concentration of kaolin clay was similar to the biomass concentration in a membrane bioreactor (10 g/L). The effects of scouring and permeate flux rates were studied in terms of the membrane fouling rate. A linear relationship between the transmembrane pressure (TMP) and particle deposition was established for different air flow rates and permeate flow rates. Air scouring was more effective at a low permeate flux. There was only a minor change in the mean particle size of deposited colloidal particles on the membrane at a given flux under varying air flows and at the beginning all had a similar rise in TMP. However, at the later stages as particles accumulated on the membrane surface there was a significant rise in TMP. 15 LMH flux was observed as critical flux beyond which a rise in the permeate flux showed a sharp rise in the TMP which varied with air flow rates and particle deposition. The sharp TMP rise that occurred during the initial few hours of operation indicated that air flow for fouling mitigation strategies should target this period to optimise the membrane process. The study showed that air flow and flux rates are the two major governing factors for particle deposition on the membrane surface

Measuring treatment effectiveness of urban wetland using hybrid water quality - Artificial neural network (ANN) model

Constructed wetlands are now commonly used as tertiary treatment for urban stormwater. The wetlands have primary advantage over other forms of treatment as they remove dissolved organics and heavy metals in conjunction with other pollutants. The effectiveness of a wetland is a primary concern for validating its compliance with design objectives and regulatory requirements. The treatment in a wetland is however complex and is dependent on input pollutants, hydraulics, physicochemical balance and biota within the wetland. Several models are available for wetlands but have limitations in simulating the physico-chemical and biological processes within the wetland. The aim of this paper is to introduce a hybrid modelling approach that involves both a deterministic model and artificial neural network (ANN) for testing the effectiveness of a constructed wetland at Olympic Park, Homebush, Sydney, Australia. This novel approach allows a combination of calibrated water quality and neural based models to predict the water quality from the wetland. The models were calibrated and validated using water quality monitoring data measured for eight months in both influent and effluent streams of the wetland. The calibrated hybrid models were then tested for treatment effectiveness for range of wet, dry and median flows conditions within the catchments. A water quality index was developed and used to quantify the effectiveness of the wetlandclose66

Rural unemployment pushes migrants to urban areas in Jiangsu Province, China

Migration is often seen as an adaptive human response to adverse socio-environmental conditions, such as water scarcity. A rigorous assessment of the causes of migration, however, requires reliable information on the migration in question and related variables, such as, unemployment, which is often missing. This study explores the causes of one such type of migration, from rural to urban areas, in the Jiangsu province of China. A migration model is developed to fill a gap in the understanding of how rural to urban migration responds to variations in inputs to agricultural production including water availability and labor and how rural population forms expectations of better livelihood in urban areas. Rural to urban migration is estimated at provincial scale for period 1985–2013 and is found to be significantly linked with rural unemployment. Further, migration reacts to a change in rural unemployment after 2–4 years with 1% increase in rural unemployment, on average, leading to migration of 16,000 additional people. This implies that rural population takes a couple of years to internalize a shock in employment opportunities before migrating to cities. The analysis finds neither any evidence of migrants being pulled by better income prospects to urban areas nor being pushed out of rural areas by water scarcity. Corroborated by rural–urban migration in China migration survey data for 2008 and 2009, this means that local governments have 2–4 years of lead time after an unemployment shock, not necessarily linked to water scarcity, in rural areas to prepare for the migration wave in urban areas. This original analysis of migration over a 30-year period and finding its clear link with unemployment, and not with better income in urban areas or poor rainfall, thus provides conclusive evidence in support of policy interventions that focus on generating employment opportunities in rural areas to reduce migration flow to urban areas