33,810 research outputs found
Prediction of sedimentation and bank erosion due to the construction of Kahang Dam
River impoundments continue to cause changes to the hydrological regimes of its host river. Thus,
assessment and development of tools for better understanding of the sediment dynamics and
riverbank erosion downstream the dam will be of great benefit to researchers and policymakers.
The present research employs the use of field techniques and estimation models to improve the (i)
prediction of suspended sediment concentration, (ii) monitoring riverbank erosion, and (iii)
development of Riverbank Erosion Index (RbEI) for downstream Kahang Dam. This research used
the Artificial Neural Network (ANN) and ANN with Autoregressive (AR) (NNETAR) in
predicting suspended sediment concentration using sediment concentration, discharge and water
level as inputs. Similarly, erosion pins were installed on four transects to monitor the riverbank
for thirteen months. The results obtained for sediment concentration prediction clearly show that
the R2 for NNETAR (0.885) have better value compared to ANN (0.695) even though the
relationship between discharge and sediment concentration was weak, it outperforms the ANN.
While based on the sediment rating curve (SRC) results, the same pattern was exhibited where the
R2 for NNETAR show a greater value than ANN and SRC with R2 values of 0.695 and 0.451,
respectively. Based on the observed results of quantified riverbank erosion, the most active
transect eroded 1.747 mm/yr- while 0.657 mm/yr- is the least eroded. furthermore, the result
reveals the maximum and minimum sediment contribution to the fluvial system from riverbank
eroded to be 0.00743 tonnes/yr and 0.00148 tonnes/yr respectively. Lastly, by using discharge and
percentage soil composition (sand and clay), a RbEI was developed by the adopted Equation 4.7
to estimate the status of riverbank erosion of River Kahang. Moreover, five classifications of
erosion status were proposed, which can be used to describe the status and severity of the riverbank
erosion. In conclusion, the estimates by the RbEI is expected to serve as basis for analysing and
adopting river stabilisation and restoration design, which will be of importance to dam operators
in making informed decisions regarding early warnings on the riverbank stability. Also, reliable
sediment concentration estimation will assist in the development of catchment sediment budget
which will give an insight into the effect of situating a dam on a river in terms of sediment supply
and riverbank erosio
On Machine Capacitance Dimensional and Surface Profile Measurement System
A program was awarded under the Air Force Machine Tool Sensor Improvements Program Research and Development Announcement to develop and demonstrate the use of a Capacitance Sensor System including Capacitive Non-Contact Analog Probe and a Capacitive Array Dimensional Measurement System to check the dimensions of complex shapes and contours on a machine tool or in an automated inspection cell. The manufacturing of complex shapes and contours and the subsequent verification of those manufactured shapes is fundamental and widespread throughout industry. The critical profile of a gear tooth; the overall shape of a graphite EDM electrode; the contour of a turbine blade in a jet engine; and countless other components in varied applications possess complex shapes that require detailed and complex inspection procedures. Current inspection methods for complex shapes and contours are expensive, time-consuming, and labor intensive
Nonterrestrial utilization of materials: Automated space manufacturing facility
Four areas related to the nonterrestrial use of materials are included: (1) material resources needed for feedstock in an orbital manufacturing facility, (2) required initial components of a nonterrestrial manufacturing facility, (3) growth and productive capability of such a facility, and (4) automation and robotics requirements of the facility
ARMD Workshop on Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation
This report documents the goals, organization and outcomes of the NASA Aeronautics Research Mission Directorates (ARMD) Materials and Methods for Rapid Manufacturing for Commercial and Urban Aviation Workshop. The workshop began with a series of plenary presentations by leaders in the field of structures and materials, followed by concurrent symposia focused on forecasting the future of various technologies related to rapid manufacturing of metallic materials and polymeric matrix composites, referred to herein as composites. Shortly after the workshop, questionnaires were sent to key workshop participants from the aerospace industry with requests to rank the importance of a series of potential investment areas identified during the workshop. Outcomes from the workshop and subsequent questionnaires are being used as guidance for NASA investments in this important technology area
Latest Developments in Industrial Hybrid Machine Tools that Combine Additive and Subtractive Operations
Hybrid machine tools combining additive and subtractive processes have arisen as a solution to increasing manufacture requirements, boosting the potentials of both technologies, while compensating and minimizing their limitations. Nevertheless, the idea of hybrid machines is relatively new and there is a notable lack of knowledge about the implications arisen from their in-practice use. Therefore, the main goal of the present paper is to fill the existing gap, giving an insight into the current advancements and pending tasks of hybrid machines both from an academic and industrial perspective. To that end, the technical-economical potentials and challenges emerging from their use are identified and critically discussed. In addition, the current situation and future perspectives of hybrid machines from the point of view of process planning, monitoring, and inspection are analyzed. On the one hand, it is found that hybrid machines enable a more efficient use of the resources available, as well as the production of previously unattainable complex parts. On the other hand, it is concluded that there are still some technological challenges derived from the interaction of additive and subtractive processes to be overcome (e.g., process planning, decision planning, use of cutting fluids, and need for a post-processing) before a full implantation of hybrid machines is fulfilledSpecial thanks are addressed to the Industry and Competitiveness Spanish Ministry for the support on the DPI2016-79889-R INTEGRADDI project and to the PARADDISE project H2020-IND-CE-2016-17/H2020-FOF-2016 of the European Union's Horizon 2020 research and innovation program
Service Knowledge Capture and Reuse
The keynote will start with the need for service knowledge capture and reuse for industrial product-service systems. A novel approach to capture the service damage knowledge about individual component will be presented with experimental results. The technique uses active thermography and image processing approaches for the assessment. The paper will also give an overview of other non-destructive inspection techniques for service damage assessment. A robotic system will be described to automate the damage image capture. The keynote will then propose ways to reuse the knowledge to predict remaining life of the component and feedback to design and manufacturing
Stent optical inspection system calibration and performance
Implantable medical devices, such as stents, have to be inspected 100% so no defective ones are implanted into a human body. In this paper, a novel optical stent inspection system is presented. By the combination of a high numerical aperture microscope, a triple illumination system, a rotational stage, and a CMOS camera, unrolled sections of the outer and inner surfaces of the stent are obtained with high resolution at high speed with a line-scan approach. In this paper, a comparison between the conventional microscope image formation and this new approach is shown. A calibration process and the investigation of the error sources that lead to inaccuracies of the critical dimension measurements are presented.Postprint (author's final draft
Automated Fiber Placement of Composite Wind Tunnel Blades: Process Planning and Manufacturing
The ability to accurately manufacture large complex shapes in a consistent and repeatable manner has led to Automated Fiber Placement (AFP) being the predominant mode of manufacturing for large composite aerospace structures today. Currently, AFP is being considered for medium- and small-scale parts. Composite wind tunnel blades have traditionally been fabricated by hand layup for pre-impregnated or dry fabrics with resin infusion. Though well proven, the traditional fabrication method is laborious and tedious, and hence expensive. The project described in this paper used the Integral Structural Assembly of Advanced Composites (ISAAC) facility at the NASA Langley Research Center to build a manufacturing demonstration unit (MDU) with a shape representative of a wind tunnel blade. This MDU is used to discuss tooling, process planning, and fabrication. Additionally, details of the generic manufacturing workflow are presented
Integration and commercialisation of tube measuring devices : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University,Manawatu, New Zealand
Failure of plant equipment in the hydrocarbon processing industry can lead to significant
financial, environmental, and health and safety consequences. Therefore, the equipment is
subject to ongoing routine inspections, which often involve significant labour and financial
resources.
Methanex is a methanol producing company operating plants at six sites globally, including in
New Zealand. The production of methanol involves the use of steam-methane reformers, which
house hundreds of process-carrying vertically hung reformer tubes in a large gas fired furnace
box. The heat and pressure of the process places the metal used for the tubes under high
stresses, which results in the creep strain phenomenon exhibited as diametric growth in the tube.
As the growth increases, the tube becomes weaker, and eventually fails. Methanex has
developed a device for inspecting the reformer tubes and detecting this growth, called the
Economole, thus helping to predict remaining tube life. However, the Economole device is not
capable of inspecting the other part of the reformer, also at risk of creep strain, the pigtail
collection pipes. These pipes are used to collect the gas at the bottom of the reformer tubes, and
are smaller in diameter. Normal practice is to manually externally inspect these pipes, costing in
excess of 100 000 NZD for Methanex New Zealand’s three reformers.
The research performed during this thesis was initiated to address the gap in internal,
automated, reformer inspection at Methanex, by integrating the field proven Economole tube
measuring device, with a laboratory tested prototype, the Minimole. Commercialisation of the
Minimole concept was carried out, to provide a fit for purpose device, and integration of
mechanical, electrical, communication and control systems was subsequently completed.
The final outcome of the project was the MXmole device. It consists of an improved Economole
system, integrated with the Minimole system.. The MXmole is able to measure the full reformer
tube, as well the top section of the reformer pigtail, during one inspection. Real time feedback is
provided on the condition of the pigtail, with instantaneous critical warnings, indicating near
end of life of the pigtail. This feedback can initiate immediate necessary replacement.
Inspection coverage for Methanex’s reformer equipment has increased as a result of this
research. This increase has provided them with additional data necessary to assess the life
expectancy of their reformer equipment, including pigtails, without the need for costly and
laborious manual external inspection. The outcome of this research may be adapted to other
plants and processes in industry, allowing further economical inspection of equipment
vulnerable to creep strain, and the overall safer and more reliable operation of high pressure and
temperature plant equipment in industry
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