345 research outputs found
Case Study: Environmental Requirements and its Impacts Upon the Conservation Center for Wildlife Care
As the population of California continues to grow, urban spaces are rapidly being developed into areas considered to be environmentally sensitive. In order to prevent extensive damage to our state’s delicate ecosystems, environmental regulations are often enforced by local organizations during the course of impactful operations such as construction projects. These regulations will often vary from one site to another, depending on a given site’s location and proximity to the environmentally sensitive areas. No two jobs will posses the exact same specifications for dealing with this aspect of construction, and as such some will require more intense regulations than others. With this in mind, the case study that I will be reporting on is an example of a job requiring the more extensive end of regulations. This paper’s objective will be to outline this specific project’s details, requirements, and discuss how it\u27s intricate situation makes it a learning experience for future projects with a similar environmental scope
Evaluating Direct Filtration as an Alternative to Conventional Carbon-Based Advanced Treatment for Indirect Potable Reuse
Hampton Roads Sanitation District (HRSD) is recharging purified wastewater into the Potomac Aquifer via the Sustainable Water Initiative for Tomorrow (SWIFT) project. Conventional SWIFT treatment applies coagulation, flocculation, sedimentation, ozonation, biofiltration, granular activated carbon (GAC) adsorption, and ultraviolet disinfection to secondary effluent to produce water that meets drinking water standards for managed aquifer recharge. HRSD is considering implementing direct filtration as an alternative to conventional treatment for two additional SWIFT facilities. Direct filtration presents an opportunity for significant cost savings by eliminating sedimentation, shortening flocculation detention time, and reducing coagulant usage. Without upstream removal of solids and organics, however, biofilters may have difficulty meeting turbidity requirements, and downstream GAC contactors may require more frequent media replacement, potentially increasing operating costs more than estimated savings. Additionally, a lower coagulant dose may not be sufficient to meet permitted phosphorus discharge requirements for when treated water is diverted to a receiving surface water. As a result, a pilot study was developed comparing conventional and direct filtration under variable operating conditions to determine the feasibility of direct filtration for HRSD’s York River Treatment Plant (YRTP) and Nansemond Treatment Plant (NTP).
Conventional and direct filtration pilot operations were evaluated for both YRTP tertiary denitrification filter effluent and NTP secondary clarifier effluent. At a 3.8 gpm/sf loading rate and 10-minute empty bed contact time (EBCT), direct filtration achieved filter effluent turbidity less than 0.15 NTU with a mean filter runtime of 35 hours for YRTP, while a mean runtime of 19 hours was achieved for NTP, a more turbid source water. In comparison, conventional treatment for YRTP and NTP achieved considerably longer mean filter runtimes of 105 and 65 hours, respectively. Mean total organic carbon (TOC) removal efficiency through direct filtration was comparable for both source waters, 35% for YRTP and 34% for NTP. Conventional treatment demonstrated greater TOC removal, 41% for YRTP and 44% for NTP. At a 2.5 gpm/sf loading rate and 15-minute EBCT, NTP direct filtration achieved longer filter runs (43 hours) and enhanced TOC removal (39%). Under similar operating conditions for NTP conventional treatment, mean filter runtime increased to 128 hours and mean TOC removal increased to 48%. Direct filtration with 0.8 mg-Al/L of aluminum chlorohydrate (ACH) addition achieved sufficient phosphorus removal for YRTP but not for NTP. Aluminum sulfate achieved more phosphorus removal per unit aluminum than ACH but resulted in shorter filter runs and less efficient TOC removal for both conventional and direct filtration. Direct filtration managed spikes in total suspended solids and turbidity up to 49 mg/L and 8.7 NTU, respectively. The pilot study results demonstrated direct filtration is a feasible alternative to conventional treatment, while its implementation is dependent on a cost-benefit analysis
Automatic Recognition of Light Microscope Pollen Images
This paper is a progress report on a project aimed at the realization of a low-cost, automatic, trainable system "AutoStage" for recognition and counting of pollen. Previous work on image feature selection and classification has been extended by design and integration of an XY stage to allow slides to be scanned, an auto focus system, and segmentation software. The results of a series of classification tests are reported, and verified by comparison with classification performance by expert palynologists. A number of technical issues are addressed, including pollen slide preparation and slide sampling protocols
Conflict transformation through prior consultation? Lessons from Peru
This article analyses the background to and the content of the Peruvian
prior consultation law - the only one enacted in Latin America to date - and its regulating
decree. In contrast to the widespread conception that prior consultation is a
means for preventing and resolving conflict, it argues that this new legislation will
not help to transform conflicts as long as the normative framework itself is contested
and the preconditions for participatory governance are not in place. Establishing these
preconditions would result in state institutions capable of justly balancing the diverse
interests at stake; measures that reduce power asymmetries within consultations; and
joint decision-making processes with binding agreements
Contesting the hydrocarbon frontiers: state depoliticizing practices and local responses in Peru
Based on primary sources, this article analyzes 150 participatory events related to planned hydrocarbon projects in Peru (2007-2012). Therein, it sheds light on state depoliticizing practices and local populations' contestations thereof. We argue that participation in the extraction sector has not enabled effective participation and has instead been used to pave the way for expanding the extractive frontiers. We find that the state entity responsible for carrying out the events applied three main depoliticizing practices: (a) the organization of exclusionary participatory processes, (b) the provision of pro-extraction information, and (c) the identification of critical actors and discourses in order to formulate recommendations on how to weaken resistance against the planned activities. This study also reveals that local populations often contested the participatory events and identifies subnational patterns of local contestation. We find that higher degrees of contestation were fueled by previous negative experiences with extraction activities and the existence of local economic alternatives. To assess the histories and results of contestation over specific extractive activities over time, the study draws on monthly conflict reports produced by the Peruvian ombudsperson (2007–2016). We find that local contestation was quite influential, leading to increased social investment programs in the affected areas, the withdrawal of several extraction corporations, and Peru's adoption of the Law on Prior Consultation (2011). However, the long-term prospects of the transformations provoked by repoliticizing processes need to be evaluated in the years to come
Prior Informed Consent – the Case of Peru: The Wrong Kind of Right? Prior Consultation between Contestation and Meaninglessness in the Peruvian Amazon
Sir William H. Beaumont and the Natives Land Commission, 1913-1916.
Thesis (M.A.)-University of Natal, Durban, 1976.No abstract availabl
Plasma-arc cutting control : investigations into machine vision, modelling and cutting head kinematics : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering at Massey University, Manawatu, New Zealand
Figures 2.2 to 2.6 have been removed for copyright reasons but may be accessed via their source listed in the References: Fig 2.2 = Fig 1 Giraud et al., 2006; Fig 2.3 = Fig 1 Colt, 2015; Fig 2.4 = Fig 7 Freton et al., 2003; Fig 2.5 = Fig 7 Colombo et al., 2009 & Fig 2.6 = Fig 8 Giraud et al., 2006.Plasma-arc cutting (PAC) is widely used in industry, but it is an under-researched fabrication tool. A review of the literature reveals much study is needed to improve the PAC process regarding efficiency, quality, stability and accuracy. This research investigated a novel control method for PAC. The PAC process was investigated to identify the gaps, and develop feasible methods, methodologies and systems to improve the PAC cutting quality and process control using machine vision. An automated, visual-inspection algorithm was successfully developed. The algorithm uses NC code to path plan and perform kerf width measurement. This visual inspection facilitated research into several aspects of PAC such as the extent of radiative heat transfer, the significance of kerf asymmetry, and a model describing the slope of the leading edge of the kerf-with respect to feed rate and material thickness. A kinematic investigation was conducted on 3 bevel capable plasma heads to complete the elements of a novel control method.
An automated, visual-inspection (AVI) system for PAC was designed that consists of a vision unit and a mounting rig. This system is able to perform real-time, kerf width measurement reaching an accuracy of 0.1mm. The methodology was validated by experiment, testing cuts on parts with varying size, shape and complexity. The outcomes of this research were published in the International Journal of Mechanical and Production Engineering and the proceedings of the 2017 Mechatronics and Machine Vision in Practice (M2VIP) international conference.
With this developed vision rig, further research was conducted such as an empirical investigation into the relationship between kerf angle and kerf width with respect to torch height, feed rate and material thickness. This investigation was comprised of 35 combinations of the process parameters with 9 replicates for each. A relationship between the process parameters and quality measures was developed, and the magnitudes of kerf asymmetries were quantified.
The understanding of the phenomenology of PAC is deficient in several areas. An experimental study was undertaken that reduced the effects of heat transfer by conduction and convection in order to estimate the contribution by radiative heat transfer. This experimental study maintained an arc between a water-cooled anode and plasma torch for 15 seconds. A test piece was specifically designed with imbedded, resistance-temperature-device thermometers positioned around the transferred arc and the temperature was measured. This investigation was able to estimate the effects of radiation from the plasma-arc. The study found radiative heat transfer is less than 3% of the total power input.
Another experimental study obtained information on the shape of the leading edge of the kerf. For this study slots were cut into steel plates of 6, 8 and 10mm thickness, at feed rates between 350 and 2000mm/min with a torch height of 1.5mm. Edge points for the centre axis of the leading profile were obtained. A relationship between surface angle and material thickness and feed rate was established and is validated through the test range.
A study on obtaining cutting profile data on the front face of the kerf was also undertaken. Slots were cut into plates of 6 and 10mm thickness. Edge points were obtained for the front 180 degrees of the kerf face at sections in 2mm increments. A 3D representation of the shape of the face was then able to be presented.
Finally, the kinematics for 3 bevel capable PAC heads was developed. Two of the heads are existing industrial heads, and the third head is being developed by Kerf Ltd. The kinematics investigation produced the DH parameters and transformation matrices for the forwards kinematics. These were validated using MATLAB®. The resulting dynamics were also produced.
In conclusion, PAC is a complicated process. This research carried out several studies and has addressed several literature gaps with the proposed methods, methodologies and systems, developed through machine vision and PAC head kinematic study.
This research was funded by Callaghan Innovation PhD research funding and received financial support from Kerf Ltd. Callaghan Innovation is a New Zealand government research funding body. Kerf Ltd. is a New Zealand PAC machine manufacturer and distributor
Enzyme Effect and Pesticide Use History in the Degradation of Pesticides
Soil is a heterogenous mixture of humus and minerals containing both immobilized enzymes and occluded microbial cells. Each of the organic and mineral fractions in soil has a special influence on enzyme activity. Soil enzyme activity results from accumulated enzymes and from the enzymatic activity of proliferating microorganisms. Microbial populations have developed to the point that short residual times have occurred for an applied pesticide. The target pest is not controlled and these soils are referred to as “problem soils. The objective of this study was to ascertain the relationship between soil enzyme activity and pesticide persistence in soils with a particular pesticide use history. One experiment involved a soil in which carbofuran failed to control insect infestation, apparently due to rapid degradation. This soil, the Centerville soil, was treated with several organophosphate and carbamate pesticides. The other experiment involved a soil from a region in Illinois with widespread isofenfos failure. The Illinois soil with several pesticide use histories was treated with isofenfos. Pesticide residue analyses and determinations of enzyme activities were then performed on the soils during the course of degradation. Rapid pesticide degradation and correlating high enzyme activity did occur in this study. There was also evidence that the process that produces a problem soil is reversible
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