Bulk Loading Research Articles

NOx reduction system selection and energy efficiency impact evaluation for ships sailing in restricted areas

The worldwide shipping provides 90 percent of the goods carriage and in the last 20 years their absolute volume is constantly increasing. However, carriers need to maintain service levels and reduce exploitation costs, and at the same time must ensure higher sustainability in all operations. The growth in number of ships in service inevitably leads to much more harmful emissions released by vessels in to the atmosphere. In the same time, more stringent environmental requirements and laws continue to regulate the maritime transport sector. Progress was made by International Maritime Organization (IMO) towards the ambition on reduction of greenhouse gas (GHG) emissions from ships. That is why IMO based International Convention for the Prevention of Pollution from Ships (MARPOL Convention) and its regulations continuously sets higher thresholds for environment protection expressed by Nitrous Oxides (NOx), Sulphur Oxides (SOx) and Carbone Dioxides (CO2) limitations. The new higher ecological requirements put on the table new technical and economic challenges for the shipowners and ship designers.In the current paper Selective Catalytic Reduction (SCR) and Exhaust Gas Bypass (EGR) NOx emissions reduction systems and their affect on the fuel consumption are under consideration. The application of each system depends on the ship’s type, installed propulsion system and its main engines and operational modes.The numerical study is carried based on 31800 DWT vessel for bulk loads, operating in restricted areas of the Great Lakes of North America. In the course of the research the fulfilment of the following objectives are being leaned: the ship must be capable for operation in Nitrogen Emission Control Areas (NECA’s), as well as its Energy Efficiency Design Index (EEDI) must be in compliance with Required Energy Efficiency Design Index (REEDI) Phase 3 coming in force in 2025.

Assessment of Fish Diversity in the Ma'an Archipelago Special Protected Area Using Environmental DNA.

This study aimed to investigate the practical validity of the environmental DNA (eDNA) method for evaluating fish composition and diversity in different habitats. We evaluated the fish composition and diversity characteristics of seven different habitats in the Ma'an Archipelago Special Protected Area in April 2020. The results showed that a total of twenty-seven species of fishes belonging to six orders, eighteen families, and twenty-three genera of the Actinopterygii were detected in the marine waters of the Ma'an Archipelago Special Protected Area. The dominant species in each habitat were Larimichthys crocea, Paralichthys olivaceus, and Lateolabrax maculatus. The mussel culture area had the highest number of species, with 19 fish species, while the offshore bulk load shedding platform had the lowest number of species, with 12 fish species. The rest of the habitat was not significantly different. The results showed that the mussel culture area had the highest diversity index (average value of 2.352 ± 0.161), and the offshore bulk load shedding platform had the lowest diversity index (average value of 1.865 ± 0.127); the rest of the habitat diversity indices did not differ significantly. A comparison with historical surveys showed that the eDNA technique can detect species not collected by traditional methods such as gillnets and trawls. Our study demonstrates the role of eDNA technology in obtaining fish diversity in different habitats and provides a theoretical basis for the continuous monitoring and management of fish biodiversity in protected areas.

Waffle

Although several spatial indexes achieve fast query processing, they are ineffective for highly dynamic data sets because of costly updates. On the other hand, simple structures that enable efficient updates are slow for spatial queries. In this paper, we propose Waffle , a workload-aware, query-sensitive spatial index, that effectively accommodates both update- and query-intensive workloads. Waffle combines concepts of the space and data partitioning frameworks, and constitutes a complete indexing solution. In addition to query processing algorithms, it includes: (i) a novel bulk loading method that guarantees optimal disk page utilization on static data, (ii) algorithms for dynamic updates that guarantee zero overlapping of nodes, and (iii) a maintenance mechanism that adjusts the tradeoff between query and update speed, based on the workload and query distribution. An extensive experimental evaluation confirms the superiority of Waffle against state of the art space and data partitioning indexes on update and query efficiency.

Uzamsal Verilerde İndeks Kullanımının Sorgu Verimliliği Üzerinde Etkileri

Indexing spatial data is of great importance in terms of accessibility and query performance to this data. In this study, query performances between indexed and non-indexed tables and bulk loading times of different sizes of data into index structures were measured by performing some query experiments on a spatial database created on the Turkey map. In this way, it is aimed to emphasize the importance of choosing the right index type and using indexes on spatial data.

Numerical frameworks for fretting fatigue life analysis: Modeling, validation and experimental comparison

A comparison of four numerical frameworks employed for the fretting fatigue life estimation of standard metallic specimens is presented. The frictional contact frameworks are: a Node-To-Node contact formulation using the boundary element method, a Node-To-Segment and a Segment-To-Segment contact formulations coupled to the finite element method, and a dual mortar formulation. The analysis procedure, repeated using each framework, is performed in three steps. The first step is the evaluation of the stress history during one loading cycle of a standard fretting fatigue setup which includes normal load, bulk load and shear load. In the second step, a critical plane approach is used to obtain the shear stress amplitude and the maximum normal stress. The final step is to employ a criterion to estimate the fatigue life. Based on previous works, the Fatemi–Socie method is selected. The validation of the stresses computed by the numerical models are carried-out using analytical formulae while the fatigue life estimations are compared to experimental data. A discussion on the performance of each framework is also provided.

Presentation of thermodynamic and dynamic modules methods to investigate the effect of nano hydrated lime on moisture damage of stone matrix asphalt

ABSTRACT Stone matrix asphalt (SMA) mixtures are the most resistant type of asphalt mixtures today in which the aggregate skeleton bears the bulk load. In this study, the effect of nano hydrated lime (NHL) on the moisture sensitivity of SMA mixtures was investigated. To examine the effect of NHL, the surface free energy (SFE) method and the dynamic modulus (DM) test were applied under wet and dry conditions on mixtures constructed with limestone and granite aggregates. The SFE results indicated that the granite aggregates had a greater polar component and limestone aggregates had a higher non-polar component which shows their higher moisture resistance. The adhesion free energy (AFE) results showed that the adhesion of base bitumen and limestone aggregate was higher, and using NHL improved the AFE values. The results of DM tests indicated that as the load cycles raised, the wet to dry DM ratio reduced and using NHL increased this ratio. The reduction slope of the DM ratio in samples constructed with granite aggregates showed a faster trend compared to limestone aggregates, and using NHL improved the resistance of SMA mixtures constructed with granite aggregates to moisture more than limestone aggregates.

The effect of phase difference and stiffness ratio on fretting fatigue behavior under variable normal load conditions

This paper investigated the effect of variable normal load on the fretting fatigue mechanism. A kinetics-based Q- P curve analysis method was proposed to assist testing system design and experiment result analysis. Based on this method, a biaxial fretting fatigue testing system was designed. Experimental and numerical investigation was carried out to discuss the effect of biaxial loading phase difference (the phase difference between bulk load and cyclic normal load) and stiffness ratio (the stiffness ratio between pad fixture and flat specimen) on the fretting fatigue mechanism. Based on the critical plane approach and proposed Q- P curves analysis method, it is found that the fretting status is partial slip regime under small stiffness ratio conditions. The stress/strain which is influenced by phase difference is the main factor of fretting fatigue damage in this condition. Furthermore, the mean stress of the normal load on the critical plane is compressive stress. It directly influences the fatigue damage under partial slip regime. With the increase of stiffness ratio and phase difference (from 0° to 90°), the fretting status changes from partial slip regime to gross slip regime, which means that the influence of wear increases. Wear inhibits the initiation of fatigue cracks, which has a positive influence on fretting fatigue life. As a result, the fretting failure mode gradually changes from fatigue to wear.

Four actuators fretting fatigue rig and tests with cyclic normal load for Ti-6Al-4V

In the present paper, a new four actuators fretting fatigue rig is presented. This machine is capable of performing tests at high or room temperature. Further, it is possible to independently control all the loads involved in the fretting tests (bulk, normal and tangential loads) in a static and cyclic way. In order to evaluate the influence of cyclic normal load on the fretting case, a new set of fretting fatigue and coefficient of friction tests were carried out for the Ti-6Al-4V alloy. Also, a finite element model (considering and neglecting wear) was used in conjunction with a critical plane parameter (SWT) and a non-local stress averaging approach to estimate fretting life. The experimental results have shown that cyclic normal load has a beneficial effect on fretting life compared with those under constant normal load. Further, no significant difference was noticed for the coefficient of friction measured under static and cyclic normal load conditions. Concerning the life estimate approaches considered in this work, for the constant normal load case, both implemented methodologies, whether accounting or neglecting wear, provided satisfactory results, with the former being slightly more accurate. However, life estimates were more accurate for the cyclic normal load case when disregarding wear.

Effective Volt/var Control for Low Voltage Grids with Bulk Loads

This paper investigates the voltage and reactive power control problem in low voltage grids with connected prosumers and bulk loads. The X(U) local control, which maintains the voltage at the feeders’ ends within a predefined band, and its combination with Q-Autarkic customer plants are the most effective and reliable strategies in grids with high prosumer share. However, these strategies may need adaptations to guarantee voltage limit compliance when bulk loads, such as electric vehicle parking garages and community-owned photovoltaic systems, are connected to the low voltage feeders. This paper extends the X(U) local control concept to involve bulk loads in Volt/var control and investigates the resulting load flows in different real low voltage grids. The results show that the extended control arrangement reliably removes all voltage limit violations by deteriorating the effectiveness of the original X(U) local control arrangement: reactive power flows and equipment loading within the low voltage grids are increased.

Improved Cell Design using Digital Ergonomic Tools

Work related Musculoskeletal Disorder (MSD) such as back pain, erroneous body postures, osteoarthritis, fibromyalgia, carpal tunnel syndrome, eye strain are exacerbated mainly due to the intensity of work and working environment. These Musculoskeletal Disorders (MSD) are cumulatively called monotonous injury or overuse injury. These injuries arise due to various reasons such as lifting of bulk load, vibrations, surrounding noise, bending, stretching, awkward posture in the workplace. This results in discomfort among the workers and decreases the productivity rate. Poor ergonomics disrupts the working environment of the employee and may cause partial paralysis. Hence application of ergonomic solutions is necessary to overcome difficulties including muscle exhaustion, tiredness, boredom among the workers because of tedious processes for a long time. This journal is concerned with the improvement of assembly cell design using digital ergonomic tools. This study was based on the workers and working environment of the manufacturing industries. The objective of the work is to analyse and simulate the discomforts faced by the workers in the assembly cell using a software named DELMIA. The purpose of this ergonomic program is to eradicate work related Musculoskeletal Disorder and to reduce stress level, so that employee performance is enhanced. This improves the production efficiency in an assembly cell

Разработка имитационной модели динамики карьерного автосамосвала для определения нагрузок, действующих на несущую систему и грузовую платформу при загрузке и разгрузке дисперсного груза

It is important for mining dump trucks to minimize the weight of the carrier and the load platform while maintaining a sufficient level of their rigidness and strength. This requirement significantly affects the weight of the transported material, the cost of transportation and, consequently, the economic efficiency of mining operations. Processes of loading and dumping of bulk loads, which is transported by dump trucks, make a significant contribution to reducing the service life of the carrier. Therefore, proper consideration of the bulk load dynamics is an important and relevant task. Contemporary systems for calculating the dynamics of solids allow for joint modeling with applications designed to calculate the dispersed body dynamics. This approach helps to obtain adequate loads in the pivots and force links of the model, to analyze the loading of the load platform, to asses the durability of the dump truck elements, to define the geometry of the load platform. In order to perform the simulation, it is required to develop a mathematical model of a dump truck, including all its key elements and subsystems, a model of the bulk load, and a model of the load platform. The purpose of the study is to develop a mathematical model of a mine dump truck to determine the loads in the pivots and force links connected to the carrier and the load platform for the strength calculations and durability analysis. The calculations are made with the combined use of the solids dynamics calculation system and the application to calculate the dynamics of dispersed bodies.

Stress state of hydrotechnical facilities resistant to natural disasters

The equations of the theory of the stress-strain state of an elastic body for practical engineering structures of the agro-industrial complex do not have analytical solutions. Therefore, the development of numerical methods for determining the strength parameters of agricultural facilities is an urgent task. Among the numerical methods of strength calculations, the finite element method is currently widely used. In a Cartesian coordinate system, a finite element of a hexahedral shape is used to determine the stress-strain state of an elastic body under bulk loading in two formulations: in the formulation of the method of displacements with nodal unknowns in the form of displacements and their derivatives, and in a mixed formulation with nodal unknowns in the form of displacements and stresses. Approximation of displacements through nodal unknowns in obtaining the finite element stiffness matrix was performed using a form function, the elements of which were Hermite polynomials of the third degree. When obtaining the deformation matrix, displacements and stresses of the internal points of the finite element were approximated in terms of nodal unknowns using bilinear functions. The calculation example shows a significant advantage of using a finite element in a mixed formulation.

A Case Study Maintenance Task Allocation Analysis on Marine Loading Arm Using Reliability Centered Maintenance

Marine Loading Arm (MLA) supports all liquid bulk loading and unloading activities, especially imports of chemical raw materials such as NH3, H2SO4, and H3PO4. Therefore, to minimize the occurrence of failure it is necessary to have a treatment method. Reliability Centered Maintenance (RCM) is a maintenance method that focuses on increasing the reliability of components in the system. The RCM uses the principle of risk management to determine tasks and maintenance schedules appropriately. The RCM process is implemented using American Bureau Shipping (ABS) Guidelines. According to the results of this research, there are three types of maintenance tasks for MLA, in which category A has 14 maintenance tasks, category B has 21 maintenance tasks, and there are no maintenance tasks in category C. In all maintenance categories for Preventive Maintenance by 54% with 19 tasks, for Condition Monitoring of 37% with 13 tasks, while for Run-To-Failure of 9% with 3 tasks.

Utilization of phosphogypsum and rice husk to develop sustainable bricks

Rapid industrialization and advancement in technology have led to the creation of bulk loads of waste material. Subsequently, the management of these waste materials has been a topic of major concern due to their complex treatment processes. As a result, utilizing these wastes with new ideas has presented viable solutions to global concerns in recent years. One of them is the utilization of waste materials in manufacturing sustainable brick. In the present study, phosphogypsum (PG), rice husk ash (RHA), and cement are used in different proportions [PG-65% to 82.5%, RHA-2.5% to 15%, cement-15% to 20%] to develop sustainable bricks. The developed sustainable bricks were tested as per the Indian and ASTM Standards. Findings revealed that the compressive strength and water absorption value of composition ‘H’ [PG(77.5%). RHA(7.5%). CEMENT(15%)] meet the requirement of IS 3495:1992. The designed sustainable brick of composition ‘H' is shown to have a higher specific heat capacity than commercially available fly ash bricks (FAB) and burnt clay bricks (BCB); hence the developed sustainable brick (composition H) is found to be thermally insulated. Present research can be used by various resource persons who are active in developing sustainable construction materials or bricks from industrial wastes.

Nitrogen as an environmentally friendly suppression agent for aircraft cargo fire safety

Fire suppression systems in cargo compartments are a certification requirement for commercial aircraft safety. Halon production was banned and usage ends in 2040 according to Montreal Protocol for environmental reasons. This necessitates an alternative environmentally friendly agent. Quantitative analysis of nitrogen as agent established suitability of the suppression system. The Minimum Performance Standards specifies the qualification procedure of an agent through four scenarios – bulk load; containerised load; surface burning; and aerosol can explosion. Empirical sources from Airbus, independent computational fluid dynamics studies and small-scale cup-burner tests indicate suitability of nitrogen specific to aircraft cargo fire suppression. The nitrogen delivery system and the experimental apparatus are presented. Extensive commissioning tests verified instrumentation reliability. All the four scenarios were conducted at Cranfield University, in a replica of a wide-body aircraft cargo compartment. In a reduced oxygen environment (11%) obtained with nitrogen discharge, the aerosol can explosion tests were performed without any evidence of explosion or pressure increase beyond the expected baseline value. The surface burning scenario was completed successfully and passed the Minimum Performance Standard criteria. The maximum average temperature was found to be 220°C (limit – 293°C). All the scenarios passed the Minimum Performance Standard criteria for indicating successful prevention of Class B fire re-ignition. Similarly, the containerised and bulk-load scenarios obtained results that passed the Minimum Performance Standard criteria for successfully maintaining continued fire suppression for a specified period of time. The maximum average temperature in containerised-load fire scenario was found to be 210°C (limit – 343°C) and in bulk-load scenario was 255°C (limit – 377°C). Additional qualification criteria and system design are presented in this article according to the Minimum Performance Standard format. This work can be extended to introduce standard testing for safety critical systems, such as engine bay and lithium-ion fires.

Traffic-aware adaptive server load balancing for software defined networks

Servers in data center networks handle heterogenous bulk loads. Load balancing, therefore, plays an important role in optimizing network bandwidth and minimizing response time. A complete knowledge of the current network status is needed to provide a stable load in the network. The process of network status catalog in a traditional network needs additional processing which increases complexity, whereas, in software defined networking, the control plane monitors the overall working of the network continuously. Hence it is decided to propose an efficient load balancing algorithm that adapts SDN. This paper proposes an efficient algorithm TA-ASLB-traffic-aware adaptive server load balancing to balance the flows to the servers in a data center network. It works based on two parameters, residual bandwidth, and server capacity. It detects the elephant flows and forwards them towards the optimal server where it can be processed quickly. It has been tested with the Mininet simulator and gave considerably better results compared to the existing server load balancing algorithms in the floodlight controller. After experimentation and analysis, it is understood that the method provides comparatively better results than the existing load balancing algorithms.

Evaluating Geospatial RDF Stores Using the Benchmark Geographica 2

Geospatial extensions of SPARQL, like GeoSPARQL and stSPARQL, have been defined since 2007, and while several geospatial RDF stores have implemented a substantial part of these extensions, other stores limited their support mostly on point geometry features. A parallel process with the above was that RDF frameworks evolved in an interesting way by presenting a more mature set of geospatial features, such as GeoSPARQL support and including the latest indexing technologies. As a logical consequence, a shift in the use of RDF frameworks is to be expected, from base platforms that users extend to create more complete geospatial RDF stores, to attractive finished RDF solutions for many geospatial applications. Alongside with the ever-increasing size of linked geospatial data that semantic stores need to handle, all the above provided our group the motivation to improve our single-node systems benchmark Geographica, originally defined in 2013. Geographica 2 is more comprehensive, because it now includes new geospatial RDF stores and frameworks, big real-world datasets of many hundred million triples with up to 50 million features of complex geometries, new tests and queries that reveal the scalability of these systems. The augmented and revised real-world workload of Geographica 2 tests the efficiency of primitive spatial functions in RDF stores, their performance in the geocoding scenario against the new Census dataset in addition to many other real use case scenarios and finally includes computation of statistics for geospatial datasets. A more detailed and systematic evaluation is performed using the synthetic workload. The new scalability workload aims at discovering the limits of centralized geospatial RDF stores of various architectures. It employs a set of six well-balanced real-world datasets with highly complex geometries covering many European countries and compares three RDF stores in terms of storage space, bulk loading and query response time. In addition, a special version of the benchmark has been created for systems with limited geospatial functionality and two more systems of this category are introduced along the six systems of the main benchmark, all stressed against point-only subsets of the workloads. Three out of the eight systems use an RDBMS for the persistence layer, while some of them offer a variety of persistence options.

Investigation of the Effect of Crumb Rubber Powder and Warm Additives on Moisture Resistance of SMA Mixtures

Stone matrix asphalt (SMA) mixtures are one of the most resistant types of asphalt mixtures known to date that the bulk load is borne by the aggregate skeleton. In this research, the effect of crumb rubber powder (CRP), Vestenamer polymer, and warm additives, including Sasobit, ZycoTherm, and a porous and warm mix asphalt (PAWMA), was investigated on the moisture resistance of SMA mixtures. A segregation test was performed to determine the tendency of the polymer to separate from modified polymer bitumen under storage conditions. Also, a drain down sensitivity test was conducted to explore the bleeding phenomena and drain down of SMA mixtures. Finally, a boiling water test, as well as an indirect tensile strength (ITS) test, was applied to examine the sensitivity of mixtures to moisture. The segregation test results indicated that by the use of Vestenamer polymer, a conventional (low speed) mixer can be used instead of using a high-speed mixer, and this will be very important in the cost of rubber bitumen production. The drain down test results showed that cellulose fibers prevented the bitumen bleeding of SMA mixtures. Also, the results of the boiling water test indicated that CRP samples containing ZycoTherm had the highest moisture resistance compared to the other warm additives. Among various mixtures, 8% CRP-modified samples containing ZycoTherm resulted in the lowest amount of stripping in SMA mixtures, even more than the base sample. The ITS test results illustrated that the use of CRP, Vestenamer polymer, and warm additives had a significant effect on the ITS amounts of mixtures. Moreover, the samples containing ZycoTherm had the highest tensile strength ratio (TSR) compared to the other SMA samples.

Bulk Dye Loading for In Vivo Calcium Imaging of Visual Responses in Populations of Xenopus Tectal Neurons.

Bulk loading of neurons with fluorescent calcium indicators in transparent albino Xenopus tadpoles offers a rapid and easy method for tracking sensory-evoked activity in large numbers of neurons within an awake developing brain circuit. In vivo two-photon time-lapse imaging of an image plane through the optic tectum allows defining receptive field properties from visual-evoked responses for studies of single-neuron and network-level encoding and plasticity. Here, we describe loading the Xenopus tadpole optic tectum with the membrane-permeable AM ester of Oregon Green 488 BAPTA-1 (OGB-1 AM) for in vivo imaging experiments.

A novel algorithm of ship structure modeling and target identification based on point cloud for automation in bulk cargo terminals

Achieving port automation of machinery at bulk terminals is a challenging problem due to the volatile operation environments and complexity of bulk loading compared to the situations in container terminals. In order to facilitate port automation, we present a method of hull modeling (reconstruction of hull’s structure) and operation target (cargo holds under loading) identification based on 3D point cloud collected by Laser Measurement System mounted on the ship loader. In the hull modeling algorithm, we incrementally register pairs of point clouds and reconstruct the 3D structure of bulk ship’s hull blocks in details through process of encoder data of the loader, FPFH feature matching and ICP algorithm. In the identification algorithm, we project real-time point clouds of the operation zone to spherical coordinate and transforms the 3D point clouds to 2D images for fast and reliable identification of operation target. Our method detects and complements four edges of the operation target through process of the 2D images and estimates both posture and size of operation target in the bulk terminal based on the complemented edges. Experimental trials show that our algorithm allows us to achieve the reconstruction of hull blocks and real-time identification of operation target with high accuracy and reliability.