Low-cost Process monitoring for polymer extrusion

Polymer extrusion is regarded as an energy-intensive production process, and the real-time monitoring of both energy consumption and melt quality has become necessary to meet new carbon regulations and survive in the highly competitive plastics market. The use of a power meter is a simple and easy way to monitor energy, but the cost can sometimes be high. On the other hand, viscosity is regarded as one of the key indicators of melt quality in the polymer extrusion process. Unfortunately, viscosity cannot be measured directly using current sensory technology. The employment of on-line, in-line or off-line rheometers is sometimes useful, but these instruments either involve signal delay or cause flow restrictions to the extrusion process, which is obviously not suitable for real-time monitoring and control in practice. In this paper, simple and accurate real-time energy monitoring methods are developed. This is achieved by looking inside the controller, and using control variables to calculate the power consumption. For viscosity monitoring, a ‘soft-sensor’ approach based on an RBF neural network model is developed. The model is obtained through a two-stage selection and differential evolution, enabling compact and accurate solutions for viscosity monitoring. The proposed monitoring methods were tested and validated on a Killion KTS-100 extruder, and the experimental results show high accuracy compared with traditional monitoring approaches.

Gabions: evaluation of potential as low-cost roadside barriers

This paper evaluates the potential of gabions as roadside safety barriers. Gabions have the capacity to blend into natural landscape, suggesting that they could be used as a safety barrier for low-volume road in scenic environments. In fact, gabions have already been used for this purpose in Nepal, but the impact response was not evaluated. This paper reports on numerical and experimental investigations performed on a new gabion barrier prototype. To assess the potential use as a roadside barrier, the optimal gabion unit size and mass were investigated using multibody analysis and four sets of 1:4 scaled crash tests were carried out to study the local vehicle-barrier interaction. The barrier prototype was then finalised and subjected to a TB31 crash test according to the European EN1317 standard for N1 safety barriers. The test resulted in a failure due to the rollover of the vehicle and tearing of the gabion mesh yielding a large working width. It was found that although the system potentially has the necessary mass to contain a vehicle, the barrier front face does not have the necessary stiffness and strength to contain the gabion stone filling and hence redirect the vehicle. In the EN1317 test, the gabion barrier acted as a ramp for the impacting vehicle, causing rollover. 

A low-cost digital image correlation technique for characterising the shear deformation of fabrics for draping studies

A novel digital image correlation (DIC) technique has been developed to track changes in textile yarn orientations during shear characterisation experiments, requiring only low-cost digital imaging equipment. Fabric shear angles and effective yarn strains are calculated and visualised using this new DIC technique for bias extension testing of an aerospace grade, carbon-fibre reinforcement material with a plain weave architecture. The DIC results are validated by direct measurement, and the use of a wide bias extension sample is evaluated against a more commonly used narrow sample. Wide samples exhibit a shear angle range 25% greater than narrow samples and peak loads which are 10 times higher. This is primarily due to excessive yarn slippage in the narrow samples; hence, the wide sample configuration is recommended for characterisation of shear properties which are required for accurate modelling of textile draping.

Willingness to pay for potential enhancements to a low-cost cataract surgical package in rural southern China.

PURPOSE: To assess determinants of patients' willingness to pay (WTP) for potential components of a multi-tiered cataract surgical package offered by a non-governmental organization (NGO) in rural China. DESIGN: Cross-sectional study. METHODS: Demographic and clinical data were collected from 505 patients presenting for cataract screening or surgery in Yangjiang, China. Willingness to pay for potential enhancements to the current surgery package was assessed using a bidding format with random payment cards. RESULTS: Among 426 subjects (84.4%) completing interviews, the mean age was 73.9 ± 7.3 years, 67.6% were women and 73% (n = 310) would pay for at least one offering, with 33-38% WTP for each item. Among those who would pay, the mean WTP for food was US$1.68 ± 0.13, transportation US$3.24 ± 0.25, senior surgeon US$50.0 ± 3.36 and US$89.4 ± 4.19 for an imported intra-ocular lens (IOL). The estimated total recovery from these enhancements under various assumptions would be US$20-50 (compared to the current programme price of US$65). In multivariate models, WTP for the senior surgeon increased with knowledge of a person previously operated for cataract (OR = 2.13, 95% CI 1.42-3.18, p < 0.001). Willingness to pay for the imported IOL increased with knowledge of a previously operated person (OR = 1.85, 95% CI 1.24-2.75, p < 0.01) and decreased with age >75 years (OR = 0.61, 0.40-0.93, p < 0.05). CONCLUSIONS: Opportunities exist to increase cataract programme revenues through multi-tiered offerings in this setting, allowing greater subsidization of low-income patients. Personal familiarity with cataract surgery is important in determining WTP. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

A high-value, low-cost bubble continuous positive airway pressure system for low-resource settings:technical assessment and initial case reports

Acute respiratory infections are the leading cause of global child mortality. In the developing world, nasal oxygen therapy is often the only treatment option for babies who are suffering from respiratory distress. Without the added pressure of bubble Continuous Positive Airway Pressure (bCPAP) which helps maintain alveoli open, babies struggle to breathe and can suffer serious complications, and frequently death. A stand-alone bCPAP device can cost $6,000, too expensive for most developing world hospitals. Here, we describe the design and technical evaluation of a new, rugged bCPAP system that can be made in small volume for a cost-of-goods of approximately $350. Moreover, because of its simple design--consumer-grade pumps, medical tubing, and regulators--it requires only the simple replacement of a <$1 diaphragm approximately every 2 years for maintenance. The low-cost bCPAP device delivers pressure and flow equivalent to those of a reference bCPAP system used in the developed world. We describe the initial clinical cases of a child with bronchiolitis and a neonate with respiratory distress who were treated successfully with the new bCPAP device.

Occurrence and fate of estrogens and antibiotics in the environment evaluated by low-cost analytical methodologies

Endocrine disruptors and pharmaceuticals are considered to be concerning environmental contaminants. During the last two decades, studies dealing with the occurrence and fate of these emerging contaminants in the aquatic environment have raised attention and its number is constantly increasing. The presence of these contaminants in the environment is particularly important since they are known to induce adverse effects in the ecosystems even at extremely low concentrations. Estrogens and antibiotics, in particular, are identified as capable of induce endocrine disruption and contribute for the appearance of multi-resistant bacteria, respectively. A better assessment and understanding of the real impact of these contaminants in the aquatic environment implies the evaluation of their occurrence and fate, which is the main aim of this Thesis. Two estrogens (17-estradiol and 17-ethinylestradiol) and an antibiotic (sulfamethoxazole) were the contaminants under study and their occurrence in surface and waste waters was assessed by the implementation of enzyme linked immunosorbent assays (ELISAs). The assays were optimized in order to accomplish two important aspects: to analyze complex water samples, giving special attention to matrix effects, and to increase the sensitivity. Since the levels of these contaminants in the environment are extremely low, a pre-concentration methodology was also object of study in this Thesis. Dispersive liquid-liquid microextraction (DLLME) was developed for the preconcentration of E2 and EE2, subsequently quantified by either highperformance liquid chromatography (HPLC) and the previously optimized ELISAs. Moreover, the use of anthropogenic markers, i.e. indicators of human presence or activity, has been discussed as a tool to track the origin and type of contamination. An ELISA for the quantification of caffeine, as an anthropogenic marker, was also developed in order to assess the occurrence of human domestic pollution in Portuguese surface waters. Finally, photodegradation is considered to be one of the most important pathways contributing for the mitigation of pollutants’ presence in the aquatic environment. Both direct and indirect photodegradation of E2 and EE2 were evaluated. Since the presence of humic substances (HS) is known to have a noticeable influence on the photodegradation of pollutants and in order to mimic the real aquatic environment, special attention was given to the influence of the presence and concentration of different fractions of HS on the photodegradation of both hormones.

Can the European low-cost airline boom continue? Implications for regional airports

At a time when the traditional major airlines have struggled to remain viable, the low-cost carriers have become the major success story of the European airline industry. This paper looks behind the headlines to show that although low-cost airlines have achieved much, they too have potential weaknesses and face a number of challenges in the years ahead. The secondary and regional airports that have benefited from low-cost carrier expansion are shown to be vulnerable to future changes in airline economics, government policy and patterns of air service. An analysis of routes from London demonstrates that the low-cost airlines have been more successful in some markets than others. To attractive and historically under-served leisure destinations in Southern Europe they have stimulated dramatic growth and achieved a dominant position. To major hub cities however they typically remain marginal players and to secondary points in Northern Europe their traffic has been largely diverted from existing operators. There is also evidence that the UK market is becoming saturated and new low-cost services are poaching traffic from other low-cost routes. Passenger compensation legislation and possible environmental taxes will hit the low-cost airline industry disproportionately hard. The high elasticities of demand to price in certain markets that these airlines have exploited will operate in reverse. One of the major elements of the low-cost business model involves the use of smaller uncongested airports. These offer faster turn-arounds and lower airport charges. In many cases, local and regional government has been willing to subsidise expansion of air services to assist with economic development or tourism objectives. However, recent court cases against Ryanair now threaten these financial arrangements. The paper also examines the catchment areas for airports with low-cost service. It is shown that as well as stimulating local demand, much traffic is captured from larger markets nearby through the differential in fare levels. This has implications for surface transport, as access to these regional airports often involves long journeys by private car. Consideration is then given to the feasibility of low-cost airlines expanding into the long-haul market or to regional operations with small aircraft. Many of the cost advantages are more muted on intercontinental services.

Low-cost vibration sensors: tendencies and applications in condition monitoring of machines and structures

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia Mecânica

New and low cost plastic membrane electrode with low detection limits for sulfadimethoxine determination in aquaculture waters

Sulfadimethoxine (SDM) is one of the drugs, often used in the aquaculture sector to prevent the spread of disease in freshwater fish aquaculture. Its spread through the soil and surface water can contribute to an increase in bacterial resistance. It is therefore important to control this product in the environment. This work proposes a simple and low-cost potentiometric device to monitor the levels of SDM in aquaculture waters, thus avoiding its unnecessary release throughout the environment. The device combines a micropipette tip with a PVC membrane selective to SDM, prepared from an appropriate cocktail, and an inner reference solution. The membrane includes 1% of a porphyrin derivative acting as ionophore and a small amount of a lipophilic cationic additive (corresponding to 0.2% in molar ratio). The composition of the inner solution was optimized with regard to the kind and/or concentration of primary ion, chelating agent and/or a specific interfering charged species, in different concentration ranges. Electrodes constructed with inner reference solutions of 1 × 10−8 mol/L SDM and 1 × 10−4 mol/L chromate ion showed the best analytical features. Near-Nernstian response was obtained with slopes of −54.1 mV/decade, an extraordinary detection limit of 7.5 ng/mL (2.4 × 10−8 mol/L) when compared with other electrodes of the same type. The reproducibility, stability and response time are good and even better than those obtained by liquid contact ISEs. Recovery values of 98.9% were obtained from the analysis of aquaculture water samples.

High-Accuracy Low-Cost RTK-GPS for an Unmanned Surface Vehicle

This work presents a low cost RTK-GPS system for localization of unmanned surface vehicles. The system is based on the use of standard low cost L1 band receivers and in the RTKlib open source software library. Mission scenarios with multiple robotic vehicles are addressed as the ones envisioned in the ICARUS search and rescue case where the possibility of having a moving RTK base on a large USV and multiple smaller vehicles acting as rovers in a local communication network allows for local relative localization with high quality. The approach is validated in operational conditions with results presented for moving base scenario. The system was implemented in the SWIFT USV with the ROAZ autonomous surface vehicle acting as a moving base. This setup allows for the performing of a missions in a wider range of environments and applications such as precise 3D environment modeling in contained areas and multiple robot operations.

Low cost carriers: The case of Oporto Airport and its touristic impact in the region

Both Oporto and the North Region of Portugal definitions of tourism have evolved significantly during the past decade. In this journey it is relevant to highlight the contribution of the arrival of Low Cost Carriers (LCCs) at Francisco Sá Carneiro Airport, thus contributing to a rapid expansion of this region as a tourism destination. Hence, this work project aims to understand the touristic and economic impact motivated by the entry of LCCs in Oporto and in the North Region of Portugal and tries to understand if this event was in fact an asset in the development of the aforementioned tourism destinations.

Building 3D City Models: Testing and Comparing Laser Scanning and Low-Cost UAV Data Using FOSS Technologies

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