High-load Systems Research Articles

Data distribution system: clustering based on neural network technologies

This article is about data distribution of high load systems. We proposed a way of distribution by means of data clustering based on neural network technologies. Clustering of the test sample of data from server stations performed. This sample of data received from cloud computing server stations distributed across different data centers. Results of experimental research proved the effectivity of neural networks in case of high load data distribution.

Energy-efficient QoS-based OCDMA networks aided by nonlinear programming methods

One of the advantages of the optical code division multiple access (OCDMA) system networks over other multiple access methods is the ability to provide differentiated classes of quality of service (QoS) for different users. The performance of the OCDMA networks is mainly limited by the multi-access interference (MAI) coming from other users sharing the same spectral resources. The suitable resource allocation in OCDMA networks allows greater capacity and the reliable deployment of the available resources in the network. This work aiming at applying and analyzing four analytical optimization methods applied to energy efficiency (EE) maximization of OCDMA networks. Hence, such optimization methods were applied and their performance-complexity tradeoffs are compared, namely the augmented Lagrangian method (ALM) (Hadi and Pakravan, 2018), sequential quadratic programming method (SQP), majoration-minimization (MaMi) approach (Sun et al., 2017; Stoica, 2004), as well as Dinkelbach’s method (DK). Tests were performed considering practical and realistic OCDMA networks with a wide range of nodes, typically K={8;16;32} nodes. The evaluated optimization methods were able to achieve convergence and perform suitably to solve the optical EE-OCDMA optimization problem. However, in a few specific high loading system configurations, the DK method did not reach full convergence; besides DK processing time was much greater compared to the promising ALM, SQP and MaMi EE-OCDMA optimization approaches.

Analysis of superconducting linear synchronous motor for electromagnetic propulsion

There is a high demand for electromagnetic launchers in applications such as electromagnetic catapults and launch-assist systems for spacecraft, owing to their advantages in terms of controllability and reusability. This work proposes a double-sided superconducting-magnet linear synchronous motor capable of large thrust densities that can satisfy the demands of high-load launcher systems. Ring windings and narrow-toothed structures were applied to increase the density of the armature winding and reduce cogging-torque-induced fluctuations, and superconducting magnet with iron-core was first proposed to produce a strong air gap magnetic field. Numerical simulations are used to construct a simulation model of the motor, which is then used to study the relationships between the thrust characteristics of the motor and the dimensions of its armature and air-gap length. The results of this analysis provide information on the optimal thrust characteristics of linear motors in electromagnetic launcher systems.

Database problems of maritime transport industry on high load platform

The article says about distributed and high load systems, common problems and common instructions for solving such problems as denormalization, replication and sharding of transport and maritime aspects. The analysis of strengths and weaknesses of technology for the transport field of activity was carried out. A fragment of the code for sampling optimization is given. Conclusions about the global use of industry technology are made. When your current infrastructure starts to show the first signs that it is no longer cope with the load and if you have a 128 MB VPS - for you, it can be 10 requests per second. For corporations, it can be 10,000 requests. There is a need for scaling and optimizing the infrastructure. Maritime office needs a good monitoring system. It will help determine the very moment when it's time to scale. Stable systems for monitoring and tracking server performance trends: Munin, Zabbix, Nagios. What usually happens when the high load point is approached: slow or infinite loading of pages; random errors; broken connections from the Web server; partial loading of content (for example, there is no part of the image), and a decrease in audience activity. This direction is very modern and promising for the transport industry.

Modeling and Analysis of High-Load and High-Speed Involute Spur Gear Systems in Adverse Lubrication

ABSTRACTThis article presents a mathematical model for the meshing of involute spur gears in mixed lubrication. The model is formulated by integrating a gear meshing model with a thermal tribofilm mixed lubrication model. The resulting model can produce a number of important meshing variables from which the gear meshing performance and the tooth surface damage may be assessed. The model is used to analyze the performance of a high-load and high-speed gear system under various degrees of mixed lubrication. The results show a stronger desire to use low-module and high-pressure-angle gears than that suggested in earlier studies under good lubrication conditions. The results also show the high importance of enhanced heat transfer design of the system to prevent or reduce the possibility of the gear system migrating into temperature-induced unfavorable lubrication conditions. Although the model is developed for spur gears and results are obtained around a nominal system, the relations of the gear meshing tribology to the meshing loss and tooth surface damage behind these results should be fundamentally the same as those in other high-load and high-speed gear systems of different sizes and types. Therefore, the results and analysis may serve as qualitative guidance for the design considerations of high-performance gear systems in general.

Enhancement of Pool Boiling Heat Transfer Using Aligned Silicon Nanowire Arrays.

Enhancing the critical heat flux (CHF), which is the capacity of heat dissipation, is important to secure high stability in two-phase cooling systems. Coolant supply to a dry hot spot is a major mechanism to prevent surface burn-out for enhancing the CHF. Here, we demonstrate a more ready supply of coolant using aligned silicon nanowires (A-SiNWs), with a high aspect ratio (>10) compared to that of conventional random silicon nanowires (R-SiNWs), which have a disordered arrangement, for additional CHF improvement. We propose the volumetric wicking rate, which represents the coolant supply properties by considering both the liquid supply velocity and the amount of coolant (i.e., wicking coefficient and wetted volume, respectively). Through experimental approaches, we confirm that the CHF is enhanced as the volumetric wicking rate is increased. In good agreement with the fabrication hypothesis, A-SiNWs demonstrate higher coolant supply abilities than those of R-SiNWs. The longest (7 μm) A-SiNWs have the highest volumetric wicking rate (25.11 × 10-3 mm3/s) and increase the CHF to 245.6 W/cm2, which is the highest value obtained using nanowires among reported data (178 and 26% enhanced vs unmodulated plain surface and R-SiNWs, respectively). These well-aligned SiNWs can increase the CHF significantly with efficient coolant supply, and it can ensure high stability in extremely high thermal load systems. Moreover, our study provides nanoscale interfacial design strategies for further improvement of heat dissipation.

The effect of armature offset for the reduction of end cogging force

Along with the increased interest in high-load transport system, the linear motor has evolved from the conventional single-sided model to a double-sided model with armatures on both sides of the mover. However, the linear motor generally has armatures installed on the full length of the transport path, resulting in the increase in material costs and manufacturing time and thus limiting the application of this double-sided linear motor to long-distance transport systems. As a means to solve this problem, in this study, we propose a stationary discontinuous armature system and solve its problem which increasing the cogging force by ends between armatures.

High load capacity with ionic liquid-lubricated tribological system

Engineering polymers with high glass transition temperature have been widely used in dynamic friction systems by oil or solid lubrication. However, in high-load systems, oil lubrication is less efficient due to the viscosity decrease at higher temperatures induced by friction heat. [Bmim][PF6] ionic liquid was used and compared with traditional L-HM46 oil and solid PTFE. Taking advantage of high [Bmim][PF6] viscosity, strong steel-[Bmim][PF6] but poor PEEK-[Bmim][PF6] interaction, the [Bmim][PF6] lubricated PEEK/steel slide falls in hydrodynamic lubrication and elastohydrodynamic lubrication region under 150–1500N. While the oil and PTFE both failed to lubricate under 800N.

Reducing power consumption in LTE data scheduling with the constraints of channel condition and QoS

3GPP has developed the Discontinuous Reception (DRX) power saving mechanism, which periodically turns off the radio interface to reduce the power consumption. However, packets cannot be received during the turn-off duration, as a result that the Quality of Services (QoS) may be violated. Therefore, optimal DRX parameters should be configured to satisfy QoS and minimize power consumption. In addition, channel condition may be unstable during the transmission, so the DRX parameters should also be dynamically adjusted. In this paper, we propose the Dynamic Scheduling with Extensible Allocation and Dispersed Offsets (DXD) scheme, which is composed of two algorithms, DRX parameters decision, to determine DRX period by considering channel condition and QoS constraints, and DRX-aware scheduling, to determine whether to extend the on duration so that QoS would not be affected by DRX. Simulation results demonstrate that the proposed DXD approach can reduce power consumption up to 96.7% compared to No-DRX scheme and guarantee QoS as good as No-DRX scheme. In addition, the power consumption can be reduced by 70.1% and 45.7% compared to the Fixed-DRX (100ms), start-offset scheme and TS scheme in good channel condition. Our approach effectively reduces power consumption in varied channel conditions and high loading system and still achieves better delay satisfaction ratio than others.

Solid – Liquid separation of dairy manure: Distribution of components and methane production

Chemical treatment and screening can be an effective technique for separation of dairy cattle manure into a liquid fraction (LF) and a nutrient-rich solid fraction (SF). The optimum loading of a strong cationic polyacrylamide was found to be 43.9 g kg −1 of dry excreta. The separated SF contained 29.1% of the initial mass present in the manure and the chemicals added. The Volatile Solids (VS)/Total Solids (TS) ratio, which was 0.78 for the manure, rose to 0.82 for the SF and decreased to 0.63 in the LF. Furthermore, the SF retained 76.1, 79.9, 59.4 and 87.4% of TS, VS, Total Kjeldahl Nitrogen and Total Phosphorus, respectively. In the LF, the ratio of filtrate chemical oxygen demand (COD filtrate ) and COD due to volatile fatty acids (COD VFA ) in relation to total COD (COD T ) were 0.86 and 0.76, respectively. The percentage of anaerobically biodegradable chemical oxygen demand (COD BD ) for the LF was 83.0%. Treatment of the LF in high loading anaerobic reactors would be possible due to these COD characteristics. Specific methane production in terms of VS for the separated LF was 0.580 m 3 kg −1 . For dairy manure and SF, it was 0.320 and 0.258 m 3 kg −1 , respectively. ► Chemical treatment is an effective technique for separation of dairy manure. ► Solid fraction retained 59.4 and 87.4% of Nitrogen and Phosphorous, respectively. ► Anaerobic biodegradability of liquid fraction much higher than that of raw manure. ► Characteristics of liquid fraction allow its treatment in high load systems.

Effect of Carbon Black Addition on the Rheology Properties of Electrically Conductive PP-Graphite Composite

This investigation gives attention on the rheology characteristics of polymer composites based on graphite and carbon black as fillers for further processing using an injection molding machine. In such a high solid loading system, the particles exhibit a very strong tendency toward agglomeration. This rapidly increases the viscosity of the mixture and decreases moldability. The presence of agglomerates in the mixture in particular may result in defect within the microstructure in the final product, even though it is sometime necessary in electrical conductivity. Composite materials in this study are polypropylene (PP) as matrix, and graphite (G) and carbon black (CB) as fillers, with a varied composition according to the percentage weight (% wt) of CB. Twin screw co-rotating extruder was used for mixing materials in order to achieve the best homogeneity of this compound. The measurement results obtained using capillary rheometer equipment showed that the addition of CB to the mixture of PP/G increase the viscosity of the materials, increase the activation energy and generally reduce the fluidity of composite materials. The value of the mixture viscosity increases with increasing the number of CB, reducing the ability of materials to be formed (moldability). Material viscosity, activation energy, fluidity and moldability shows how suitable the compound material to be processed by using injection molding machine.

Use of a mathematical optimisation procedure for model calibration and enhancement of nitrogen removal in high-load systems

A mathematical optimisation method utilising the BLIND algorithm was used for model calibration and subsequent simulations on an ASM No.1. based platform. The calibration of model parameters was fulfilled with the use of operational data of a large wastewater treatment plant (of 80000 m3·d-1 capacity) owing a high-load activated sludge stage (sludge age of 1.8-2.5 d) with a subsequent nutrient removal biofiltration system. The calibrated model was applied for the optimisation of the multi-point addition of nitrifying biomass (i.e. step-seeding) and air supply in the high load system that has a bioreactor with plug flow characteristics. Results of model simulation showed, that with addition of nitrifyers in three points may enhance nitrification by about 9% comparing to the single point addition at the head of the reactor. Nitrogen removal can be further increased by about 8% with optimising air supply along the reactor length. Results showed, that the step-seeding concept may convey a potential in nitrogen removal enhancement in combined systems with separate nitrification/denitrification units, since optimised addition of the biomass can be easily performed.

Transient Vibration Suppression of Synchronous Motor Driving System with Field Circuit Control

The present study deals with transient torsional vibration problems. To suppress the torsional vibrations during the starting period, a passive element is inserted in the field circuit of a salient pole synchronous motor driving a high inertia load system. The optimal passive circuit parameters in the starting field circuit control schemes are determined by the proposed parameter optimization algorithm with the unified quadratic vibration performance indices. Computer simulation and Fast Fourier-Transform (FFT) analysis show that the transient torsional vibrations can be considerably improved when the field circuit is connected to the proposed starting control scheme. The risk of premature component failure, due to the excess of the designed limit for transient torsional stresses, can also be diminished.

Comparison of enumeration methods for ammonia-oxidizing bacteria

MPN, antibody, fluorescent in situ hybridization (FISH) and dot blot hybridization methods for enumeration of ammonia-oxidizing bacteria were applied to various samples from suspended systems. As for FISH, reoptimization of an oligonucleotide probe Nso 190 was attempted. The advantages and disadvantages of these methods were discussed. MPN appeared to have disadvantages of underestimation. Dot blot hybridization had lower detection limit and higher reliability than other methods. It could be applied to mixed liquors and effluents of municipal wastewater treatment plant (WWTPs), lab-scale reactor and enrichment cultures of ammonia-oxidizing bacteria. FISH could be successfully applied to high ammonium loading system such as enrichment cultures, but weak signal, auto-fluorescence and non-specific binding could cause problems when applied to low ammonium loading systems such as effluents of WWTPs and river water. Mixed liquor of municipal WWTP seemed to be a critical case for FISH.

Odor control for livestock systems

Odors are generated primarily as the result of manure storage but also result from animal housing and manure application. Effective odor control is dependent upon implementation of strategies that are complementary to management practices. Some systems use a deep pit or a holding tank for manure storage. In such systems, little or no biological processing occurs, and they are therefore considered high-load systems. In systems where biological processing occurs to a great extent, such as in anaerobic digesters or lagoons, the system would be termed a low-load system. Odor control strategies for manure storage areas, such as solids separation and additives, are best suited for low-load systems, whereas covers and biofilters provide the best results for high-load systems. Strategies that reduce nutrient production, such as dietary restriction of nutrients, are well-suited for all types of manure storage systems. To comply with current or pending odor control regulations, it is imperative that producers be provided with sound recommendations of odor control strategies.

Improvement of sludge settleability in activated sludge plants treating effluent from pulp and paper industries

The main objective of many activated sludge plants treating wastewater from the pulp and paper industry is to remove COD only. These plants are often designed as high-load aerobic systems without any microbial selector system. As a consequence the sludge settling properties are normally poor due to fast growing filamentous microorganisms, which severely reduce the treatment capacity and the effluent quality. Implementation of selectors, in which the substrate concentration and the metabolic pathways can be manipulated, has in many cases reduced the bulking sludge problems in activated sludge systems. An example of a successful upgrading of a Danish pulp industry wastewater treatment plant with an anoxic selector is presented. the use of a novel technique to investigate the in situ physiology of filamentous microorganisms is discussed. It is concluded that a successful application of selectors relies on detailed knowledge about: a) physiology and substrate requirement of the filamentous microorganisms, b) wastewater composition and c) substrate removal kinetics in the selector system.

Oil bath lubrication: Stringer, L. S. Industrial Lubrication, Vol 20, No 2 (February 1968) p44

Engineering polymers with high glass transition temperature have been widely used in dynamic friction systems by oil or solid lubrication. However, in high-load systems, oil lubrication is less efficient due to the viscosity decrease at higher temperatures induced by friction heat. [Bmim][PF6] ionic liquid was used and compared with traditional L-HM46 oil and solid PTFE. Taking advantage of high [Bmim][PF6] viscosity, strong steel-[Bmim][PF6] but poor PEEK-[Bmim][PF6] interaction, the [Bmim][PF6] lubricated PEEK/steel slide falls in hydrodynamic lubrication and elastohydrodynamic lubrication region under 150–1500 N. While the oil and PTFE both failed to lubricate under 800 N.

Fluid film lubrication of rubber—an interferometric study: Roberts, A. D. and Tabor, D. Wear, Vol 11, No 2 (February 1968) p163

Engineering polymers with high glass transition temperature have been widely used in dynamic friction systems by oil or solid lubrication. However, in high-load systems, oil lubrication is less efficient due to the viscosity decrease at higher temperatures induced by friction heat. [Bmim][PF6] ionic liquid was used and compared with traditional L-HM46 oil and solid PTFE. Taking advantage of high [Bmim][PF6] viscosity, strong steel-[Bmim][PF6] but poor PEEK-[Bmim][PF6] interaction, the [Bmim][PF6] lubricated PEEK/steel slide falls in hydrodynamic lubrication and elastohydrodynamic lubrication region under 150–1500 N. While the oil and PTFE both failed to lubricate under 800 N.