244 research outputs found
Statement: Eubank Lock Service
No full textStatement: Eubank Lock Service, Jacksonville, NC. Service completed at Simmons FFA Camp. Addressed to A&T College, c/o W. T. Johnson
Innovative Concepts in Navigation Lock Design and Gate Contact Aspects
No full textThis paper presents the new report n°106 of PIANC InCom WG29 on Innovations in Navigation Lock Design, published by PIANC in August 2009, as well as some additional contributions on lock gates (gate contact technology). The paper highlights the main objectives and issues of his PIANC report with a specific emphasis on gates and specifically on the contact aspects. Locks are key structures for the development of the navigation in canals and in natural rivers where weirs regulate water levels to enable navigation. They may also be strategic infrastructure for port development. The core of this report has three major parts. The first part presents an exhaustive list of design goals associated with locks. This section is particularly important for decision makers who have to launch a new project. The second part reviews the design principles that must be considered by designers. This section is methodologically oriented. The third part is technically oriented. All main technical aspects (hydraulics, structures, foundations, including computational aspects, etc.) are reviewed, focussing on changes and innovations occurring since 1986. Perspectives and trends for the future are also listed. When appropriate, recommendations are listed. It is impossible to give the details of all lock innovation areas in this paper. As an example, the lock gates and, in particular, the modern views on their contact issues have been chosen. These new solutions are welcome to limit the maintenance and to extend the service life of lock gates
Understanding the Relationship between Lock Complex Effectiveness and System Performance: A Study of the Volkerak Complex
No full textInland Waterway Transport (IWT) is an untapped resource that can be mobilised to achieve a more sustainable transport system without compromising competitiveness. It outperforms rail and road alternatives in terms of low emissions, costs, high capacity, energy efficiency, freight safety, and security. Waterway locks are ageing assets in IWT systems and are infamous for creating bottlenecks. The effectiveness and performance of these locks can be measured and integrated into decision making to establish well-informed operational, maintenance, and renewal policies. This study addresses the following research question:How can the effectiveness of waterway locks be assessed to support lock maintenance and operation? Simulation modelling, which offers an efficient and low-risk evaluation of policy options while incorporating the intrinsic variability of the system, is selected as the core methodology. The simulation model incorporates operational aspects of the system, malfunctions, corrective maintenance activities, and the calculation of various performance indicators. An extensive list of performance indicators is complied through literature research. These indicators include infrastructure occupancy, vessel waiting times, costs, and emissions. In addition to existing indicators, three formulations for Overall Equipment Effectiveness (OEE) are proposed in lock complexes. The applicability of the selected methodology is demonstrated by employing a case study of the Volkerak complex, one of the largest and busiest lock complexes in Europe. Quantitative and qualitative data, collected through operational logs, maintenance reports, and interviews with experts, support that as the lock complex gets older, malfunctions become more frequent. SIVAK, a software package utilised by the Ministry of Infrastructure and Water Management of the Netherlands ("Rijkswaterstaat", RWS), is used as the basis of the simulation model. Extensions are made to calculate additional performance indicators and to simulate fluttering doors and slowdowns, two types of malfunctions that are diagnosed to be frequent and impactful based on maintenance reports and interviews. Experiments are designed to explore the performance of different maintenance policies, such as mean time to repair (MTTR) and inspection frequency, and different operational policies such as locking regimes under various fleet mix and lock condition scenarios. Stress tests and univariate analyses are also conducted. The study findings highlight the following:- With rising demand, the significance of lock condition in maintaining acceptable service levels and minimising CO2 emissions becomes more evident. The findings indicate a trade-off between preventive and corrective maintenance efforts. In challenging lock conditions, faster repairs and more frequent inspections are needed to prevent capacity problems, leading to longer waiting times. Notable differences in handling capacity are observed in the three lock conditions studied.- The concept of baseline OEE proves to be valuable as a maintenance-oriented metric. It emphasises that proficient maintenance strategies can counteract deficiencies in the lock system, resulting in improved capacity, reduced transit times, and reduced CO2 emissions. A general rule of thumb suggests that improving baseline OEE by one point corresponds to about a 1.2%-1.5% improvement in waiting times and emissions. - Changing MTTR and inspection policies influences baseline OEE scores, but these adjustments must be aligned with the lock condition. Frequent inspections might yield unnecessary availability losses when the lock is well maintained. Similarly, the extent of benefits of shorter MTTRs depends on the frequency of breakdowns.- A prominent dilemma in lock systems involves balancing transit times and the number of levellings. Locking regimes capture this trade-off, where reducing waiting time thresholds increases levellings and operational costs. However, some strategies can achieve an improvement in both aspects. These include expanding traffic range and considering the current state of the system when assigning lock chambers to incoming vessels.- Service-based OEE, integrating operational and maintenance policies, aligns better with waiting times and CO2 emissions compared to the service level alone. This composite index can serve the purpose of monitoring waterway network lock systems, helping to identify losses due to unavailability and reduced speed.Engineering and Policy Analysi
Establishing the required lock capacity and configuration in case of canalisation of the river Waal: An exploratory study
No full textThe river Waal is part of an economic important transport-corridor that connects the ports of Antwerp, Rotterdam and Amsterdam to Germany. Ongoing processes such as (1) climate change, (2) large scale river bed erosion and (3) up-scaling of vessels threaten the future navigability of the river. This will lead to massive economic damages as taken in 2018 (Strengs et al., 2020). Canalisation of the river by means of weir-lock complexes is a considered by Rijkswaterstaat to improve inland navigation during periods of low discharge and prevent economic damages. This leads to the primary goal of this study; investigate the required lock capacity to provide smooth and reliable passage of the river Waal now and in the future. A literature review was conducted to assess the future development of the drivers of the worsening navigation conditions and to gain insight in market- and fleet developments. The developments in the drivers underline the urgency for measures. The development of the fleet navigating on the river Waal is characterised by up-scaling for the past 20 year. This trend is expected to continue the coming years. Future market developments are very uncertain due to the energy transition and the nitrogen crisis, making it very difficult to make accurate projections on future fleet intensities and compositions. Therefore a range of traffic intensities is used to characterise future fleets that encounter the lock complexes. The number and locations of the lock complexes is investigated by analysing available nautical depths and water levels along the river Waal for several stationary discharges at Lobith. Water levels are set up to a level such that navigation for all vessels (fully loaded) is possible. From a financial perspective it is most attractive to minimise the number of weir-lock complexes, however this is contrary to flood safety aspects on the river Waal. Installation of two weir lock complexes is considered plausible taking into account minimising the number of weir-lock complexes and flood safety. Vessel traffic simulations are conducted in SIVAK III to investigate the performance of multiple lock configurations in terms of average waiting time and service level. SIVAK III is able to simulate the passage of vessels at an individual level in a network of waterways and locks. A fleet analysis on a representative IVS data set is conducted to provide SIVAK III with fleet intensities, fleet mixes and arrival patterns. For the upstream (rkm 905) lock complex is recommended to use a lock complex with 4 chambers with dimensions 28.4x305m, but with in mind the option for a 5th chamber in the future. This lock complex is able to handle the current fleet +10% intensity within the considered requirements. A 5th lock chamber of the same size can handle an increased intensity of +30% including strong up-scaling effects. For the downstream lock complex (rkm 941) it is recommended to use a lock complex with 4 chambers and dimensions 25x330m. The lock complex is able to handle the current intensity +30%.Civil Engineering | Hydraulic Engineerin
Selecting examinable nursing core competencies: A Delphi project
No full textAim: To establish a set of core competencies that could be practically examined in a pre-registration practical examination for Indonesian candidates completing their pre-service education. Background: Indonesia is planning to institute a register for nurses to ensure a minimum standard of safe practice for new nurses completing their pre-service education. A proposed route to registration includes the practical examination of a minimum set of core competencies. This Delphi project aimed to reduce 192 existing standard competencies to an examinable group of 12 core competences that all nurses registering in Indonesia must meet. Method: A modified Delphi method was used by 12 expert Indonesian nurses and a facilitator to determine which standard competencies should be considered core. Results: Five Delphi rounds were used. One hundred and ninety-two standard competencies were reduced to a core set of 12. Selected competencies are assessable in a practical examination and can be used to determine a minimum level of safe practice for all nurses seeking to register at the completion of their pre-service education. Conclusion: The expert panel met the project aim and provided a set of examinable competencies/activities that they consider will demonstrate the fundamental safety of new registered nurses. The subsequent responsibility for setting up a register for nurses in Indonesia now rests with the Indonesian Ministry of Health. The Indonesian National Nursing Association is working with the Ministry of Health to determine the route and criteria for registration in order to establish a common level of competence for nurses across the country exiting their pre-service education. © 2011 The Author. International Nursing Review © 2011 International Council of Nurses
The cathedral and the bazaar of e-repository development: encouraging community engagement with moving pictures and sound
No full textThis paper offers an insight into the development, use and governance of e‐repositories for learning and teaching, illustrated by Eric Raymond's bazaar and cathedral analogies and by a comparison of collection strategies that focus on content coverage or on the needs of users. It addresses in particular the processes that encourage and achieve community engagement. This insight is illustrated by one particular e‐repository, the Education Media On‐Line (EMOL) service. This paper draws analogies between the bazaar approach for open source software development and its possibilities for developing e‐repositories for learning and teaching. It suggests in particular that the development, use and evaluation of online moving pictures and sound objects for learning and teaching can benefit greatly from the community engagement lessons provided by the development, use and evaluation of open source software. Such lessons can be underpinned by experience in the area of learning resource collections, where repositories have been classified as ‘collections‐based’ or ‘user‐based’. Lessons from the open source movement may inform the development of e‐repositories such as EMOL in the future
Het bepalen van KPI’s en normen voor het beheersen van het logistieke proces van FloraHolland
No full textThe floriculture sector is globalizing and digitizing rapidly. This affects the flows in the supply chain and the way of doing business with FloraHolland. Customers are becoming more demanding and are expecting more service. Growers decrease the use of the auction clock, and do more business via direct flows. The Logistics and Facilities Department is partly responsible for optimizing the logistics process. In this process the available data is processed in a large number of different reports. While possessing this large number of reports, FloraHolland is looking for the Key Performance Indicators (KPI’s) for the logistics process. The logistic process of FloraHolland is analyzed according to the Delft System Approach. During this analysis a number of issues were found referring to the control of the logistics process. The first observation is that the logistics process is controlled via financial control instead of logistic control. This leads to a lack of focus of an efficient logistics process and makes it hard to initiate the right process improvements. ‘Distribution Flowers’ is the largest of 13 logistics departments. This department is responsible for 39% of the working hours of the logistic process. However, the deployment of staff for this distributionprocess is determined by a planning-tool that is based on an outdated process. Also, there is no standard set for the productivity of the staff, but the productivity is chosen based on intuition and experience. In the distributionprocess the distributors transfer the casks from the auctioned trolley to trolleys which are delivered at buyers locations. The productivity of the distributors is dependent on the purchasing behavior and number of distributors because of congestion. The research question of this report is: With which KPIs and standards can FloraHolland control their logistics process in a changing environment? FloraHolland provides logistics services to growers and buyers. The demands of the growers and buyers on the logistics process can be divided in reliability, quality, throughput time and efficiency. The first three can be expressed in the percentage of casks that are missing, damaged, or took more handling time than the agreed throughput time. For an efficient process a workload should be processed with minimal resources. The most important and most expensive resource is the staff. At different stages of the process the departments are dealing with various types of workloads...Mechanical, Maritime and Materials EngineeringMarine and Transport TechnologyTransport Engineering and Logistics2014.TEL.782
Determining the Required Storage Capacity of an Import Dry Bulk Terminal
No full textCargo transport is important for supplies of goods and food worldwide. The goods and food are transported by inland transport modes, like road, railway and inland waterway transport. Due to a growth in world population the demand of goods and food increase, which results in an increase in cargo transport. More transport leads to more traffic on roads, railway and inland waterways. Roads and railways are at their limits of capacity, while inland waterways have the ability for an increase of waterway traffic. The European waterway network for inland transport is wide and connects sea ports and the European hinterland with each other. While inland waterway transport is cheaper and slower compared to road and railway transport, it is also less reliable than the other transport modes. The reliability is the ability to perform and maintain the agreements made between actors involved in the cargo transport during normal circumstances, as well as during unexpected circumstances, like delays. A disadvantage for inland waterway navigation is the locks in the waterway network. Locks maintain the water on a certain level, so that inland vessels can navigate without the risk of grounding. Locks also cause congestions when the lock capacity is lower than the amount of vessels that want to pass the lock during a certain time. These congestions cause delays for the vessels, which do not increase the reliability of the waterway transport mode. To stimulate the inland waterway transport, so that cargo transport over water will become more compatible with road and railway transport, the reliability for inland waterway transport must be increased. This can be done by decreasing the waiting times at the locks in the waterways. The interarrival times of inland vessels have an influence on the waiting times for vessels at locks. So when the arrival times of vessels at a lock are controlled, the waiting times can be controlled. A simulation model is designed to simulate what the effect of controlled arrivals of vessels is on the waiting time at locks. The simulation model is able to adjust the velocities of all vessels that navigate on the waterway towards the lock. With the adjustments in velocity of a vessels, the arrival time of that vessel is controlled by the model. The adjustment in velocity can let the vessel navigate faster and slower. When a vessel slows down it´s travel time on the waterway increases. A lower velocity and a longer travel time means that the fuel costs decrease and the operation time increases. That could result in a higher total travel costs. Therefore the simulation model can minimize the waiting times or the travel costs. With the minimization of costs the waiting time is minimized as well, due to the fixed operating costs a vessel has, which are the travel costs without fuel costs. Variables in the simulation model are the length of the controlled waterway, the service time of the lock and the lock capacity. The length of the controlled waterway determines the size of the system and the area where the vessels are controlled, the service time is the time it takes to pass the lock and the lock capacity determines the maximum number of vessels that can enter the lock chamber during one service run. As an input for the simulation model each vessel has its own entering velocity and entering time during a day. The entering velocities of the vessel are between 10 and 20 km/h and can be adjusted between 5 km/h and 110% of the entering velocity of the vessel. The entering time is distributed by a Weibull distribution. Since inland waterway transport is not yet a full 24/7 industry, the distribution is in such way that the majority of the daily vessels that pass the lock will enter the system between 06:00 and 20:00 hour. The settings used for the variables in the simulations are based on situations at four locks between the two largest sea ports in Europe, which are Rotterdam and Antwerp. The locks are the Volkerak, Krammer, Hansweert and Kreekrak lock and the waiting times at those lock are expected to be as long as 3 hours in the next decade. The output of the simulation model are waiting times at the lock and the total travel costs for each vessel in an optimized situation, which is a situation with minimized waiting time or travel costs. Optimized results of the simulation model are compared with the simulations that represent the four locks with the expected waiting times. The simulation model shows a reduction in waiting times of more than 80% compared to the expected waiting times for the next decade. If this can be achieved in reality the inland waterway transport mode can be stimulated due to smaller unexpected delays and an increased reliability.Mechanical, Maritime and Materials EngineeringMarine and Transport TechnologyTransport Engineering and Logistics2012.PEL.772
Optimization to reduce waiting times at locks
No full textCargo transport is important for supplies of goods and food worldwide. The goods and food are transported by inland transport modes, like road, railway and inland waterway transport. Due to a growth in world population the demand of goods and food increase, which results in an increase in cargo transport. More transport leads to more traffic on roads, railway and inland waterways. Roads and railways are at their limits of capacity, while inland waterways have the ability for an increase of waterway traffic. The European waterway network for inland transport is wide and connects sea ports and the European hinterland with each other. While inland waterway transport is cheaper and slower compared to road and railway transport, it is also less reliable than the other transport modes. The reliability is the ability to perform and maintain the agreements made between actors involved in the cargo transport during normal circumstances, as well as during unexpected circumstances, like delays. A disadvantage for inland waterway navigation is the locks in the waterway network. Locks maintain the water on a certain level, so that inland vessels can navigate without the risk of grounding. Locks also cause congestions when the lock capacity is lower than the amount of vessels that want to pass the lock during a certain time. These congestions cause delays for the vessels, which do not increase the reliability of the waterway transport mode. To stimulate the inland waterway transport, so that cargo transport over water will become more compatible with road and railway transport, the reliability for inland waterway transport must be increased. This can be done by decreasing the waiting times at the locks in the waterways. The interarrival times of inland vessels have an influence on the waiting times for vessels at locks. So when the arrival times of vessels at a lock are controlled, the waiting times can be controlled. A simulation model is designed to simulate what the effect of controlled arrivals of vessels is on the waiting time at locks. The simulation model is able to adjust the velocities of all vessels that navigate on the waterway towards the lock. With the adjustments in velocity of a vessels, the arrival time of that vessel is controlled by the model. The adjustment in velocity can let the vessel navigate faster and slower. When a vessel slows down it´s travel time on the waterway increases. A lower velocity and a longer travel time means that the fuel costs decrease and the operation time increases. That could result in a higher total travel costs. Therefore the simulation model can minimize the waiting times or the travel costs. With the minimization of costs the waiting time is minimized as well, due to the fixed operating costs a vessel has, which are the travel costs without fuel costs. Variables in the simulation model are the length of the controlled waterway, the service time of the lock and the lock capacity. The length of the controlled waterway determines the size of the system and the area where the vessels are controlled, the service time is the time it takes to pass the lock and the lock capacity determines the maximum number of vessels that can enter the lock chamber during one service run. As an input for the simulation model each vessel has its own entering velocity and entering time during a day. The entering velocities of the vessel are between 10 and 20 km/h and can be adjusted between 5 km/h and 110% of the entering velocity of the vessel. The entering time is distributed by a Weibull distribution. Since inland waterway transport is not yet a full 24/7 industry, the distribution is in such way that the majority of the daily vessels that pass the lock will enter the system between 06:00 and 20:00 hour. The settings used for the variables in the simulations are based on situations at four locks between the two largest sea ports in Europe, which are Rotterdam and Antwerp. The locks are the Volkerak, Krammer, Hansweert and Kreekrak lock and the waiting times at those lock are expected to be as long as 3 hours in the next decade. The output of the simulation model are waiting times at the lock and the total travel costs for each vessel in an optimized situation, which is a situation with minimized waiting time or travel costs. Optimized results of the simulation model are compared with the simulations that represent the four locks with the expected waiting times. The simulation model shows a reduction in waiting times of more than 80% compared to the expected waiting times for the next decade. If this can be achieved in reality the inland waterway transport mode can be stimulated due to smaller unexpected delays and an increased reliability.Mechanical, Maritime and Materials EngineeringMarine and Transport TechnologyTransport Engineering and Logistics2012.TEL.771
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No full textCPU verification Time-lock puzzle In this paper, a user-based CPU verification scheme is proposed for the cloud cheating detection problem, where the cloud service provider offers insufficient CPU resources that are bought by the user. In this scheme, a predefined computational task is constructed for the cloud to execute. Then, we compare the difference of the actual execution time (recorded by the user) and the theoretical execution time, as to determine whether the cloud is cheating or not. A time-lock puzzle is introduced to construct the predefined computational task, so that this task is guaranteed to be fully executed by the cloud. Our cheating detection process has a higher probability of detecting cloud cheating if using a larger predefined computational task, which in turn costs more time. Further analysis shows that, if the total detection time is limited, it is better to detect cloud cheating using small-scale and short-length cheating detecting processes multiple times, as opposed to large-scale and long-length processes a few times. We also discuss the heterogeneity of CPU resources through two simple models. Finally, the feasibility and validity of our scheme is shown in the real system evaluations
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