Operation Diagram Research Articles

Study into Improvement of the Hatch Covers of General-Purpose Open Wagons to Provide Strength under Operational Loading Diagrams

The article presents the results of research into the strength of the hatch covers of general-purpose open wagons. It was detected that strength of the standard hatch covers is not provided in operational loading diagrams. Therefore, new designs of the hatch covers for open wagons were proposed. The results of the strength calculation, implemented with the finite element method, make it possible to conclude that at basic and additional operational loading diagrams the strength values for proposed designs of hatch covers do not exceed the admissible values. The research conducted can contribute to a higher strength of the carrying structures of the bodies of general-purpose open wagons in operation, thus, guaranteeing a higher operational efficiency of the rail transport.

Investigation of dynamic characteristics of three-linear flow regulator

The study focuses on the dynamic model of the three-linear spool flow regulator for various solutions of the spool geometry, and for two variants of mathematical description of hydraulic damping devices. The paper describes the process of small deflection linearization of the obtained mathematical models. As a result of Laplace transformation of the mathematical models, we obtained a block diagram of the spool flow regulator operation. By using Nyquist criterion, we analyzed the spool flow regulator stability. As a result, we draw conclusions on the spool flow regulator stability, and on the various types of damping devices affecting it

Feasibility study on a vehicular thermoelectric generator for both waste heat recovery and engine oil warm-up

The thermoelectric modules have the bidirectional characteristic, which can work either in power generation mode based on Seebeck effect or in heating-cooling mode based on Peltier effect. In this paper, a feasibility study is performed for a bifunctional thermoelectric generator applied in vehicle engines, which can use Seebeck effect for waste heat recovery and Peltier effect for engine warm-up. To predict the bidirectional behaviours of the thermoelectric module, a dual-mode thermoelectric module model is developed, and the simulation results for the two modes (power generation mode and heating-cooling mode) are both verified with experiments. The four-quadrant operation diagram of thermoelectric module, which clearly presents the cooling, heating and power generation curves, is produced based on the validated model.A case study of applying a bifunctional thermoelectric generator to a 2 l-diesel engine passenger car is then carried out based on a further extended bifunctional TEG model and an engine oil and coolant circuit model. The simulation results shows that the optimal engine oil temperature (100 °C) cannot be reached in the new European driving cycle for the baseline engine without thermoelectric generator, but it can be reached by both applying thermoelectric generator operating in waste heat recovery mode and engine warm-up mode. Compared with the thermoelectric generator only operating in waste heat recovery mode, a 3-min faster warm-up effect of engine oil can be obtained when the bifunctional thermoelectric generator works in engine warm-up mode with electrical current applied. It also finds out that the electric power generated in waste heat recovery mode at vehicle starting and low vehicle speed phrase is limited. However, a faster warm-up effect (engine oil temperature rising 7 °C in the first 100 s) can be obtained by operating thermoelectric generator in engine warm-up mode at vehicle staring. The electric energy used in engine warm-up mode can be regenerated in the later waste heat recovery mode. To compensate all the used electric energy in engine warm-up mode, longer time of thermoelectric generator operating in waste heat recovery mode is needed.

Optimization study of jinghu highspeed railway train operation diagram

This article is based on familiarization with the technical methods of the standardized highspeed train operation diagram. Investigated the existing problems of the train working diagram of highspeed train between Beijing and Shanghai. In the process of train operation diagram compilation,analyze the difficulties based on the normalized. The operating diagrams which optimized from the various processes have been prepared from organization. The optimization plan of the normalized train operation diagram on the Jinghu highspeed train was proposed as well.

Innovative extracting of optimum operational diagrams for a CW sealed CO2 laser based on the evolutionary genetic algorithm

Views Some innovative diagram for the optimum parameters in operation of a sealed CW CO2 laser was extracted by using the evolutionary genetic algorithm. By picking up an optimum value for the cavity stability parameter, geometrical factor (g), the optimum value of other parameters such as tube diameter, tube length and the coupler transmission, are resulted by these optimum diagrams.

Intelligent scheduling method for energy saving operation of multi‐train based on genetic algorithm and regenerative kinetic energy

An intelligent scheduling method for energy saving operation of multi-train is proposed based on genetic algorithm and regenerative kinetic energy. Considering the morning and evening peak, departure time, and total vehicle number, the energy consumption optimisation model of multidimensional state vector subspace of train is established for the train departure interval with the lowest total energy consumption. Two intelligent control models are used to formulate the time interval scheduling plan depending on whether to consider the morning and evening peak. The train operation diagram is solved by Matlab, and the validity and feasibility of the proposed algorithm are verified. This study provides an intelligent and efficient algorithm and solution for multi-train intelligent scheduling problem.

Simulation of Loads on the Carrying Structure of an Articulated Flat Car in Combined Transportation

The article presents the findings of the research into loading on the carrying structure of an articulated flat car under combined transportation. The refined data of dynamic loads on the carrying structure of a flat car under train ferry transportation, as well as the main loading modes in rail track operation were determined by mathematical modeling. The adequacy of the models developed was checked with an F-test. The results of the calculation conducted made it possible to conclude that the hypothesis on adequacy of the models is not rejected. The peculiarities of the structural strength modeling for a flat car within operational loading diagrams are given. The graphics works were conducted in Solid Works. The capacity analysis was conducted by the finite element method in CosmosWorks. The 09G2S steel was used as a construction material. It is determined that the maximum equivalent loads in the flat car support structure do not exceed the admissible loads. Results of the research can be used in designing coupled flat cars to provide their capacity at mixed transportation.

Power and environmental disturbances of the production process for vegetal bio-stimulants

The paperwork aims to identify and find methods to reduce power pollution, by noise and dust released in atmosphere. According to operation diagram of the installation there are items (electrical equipment and mechanical systems), that during operation under normal mode cause power pollution like noise with parameters that may exceed the legal limits. Damage of quality indicators of the power can be avoided by continuous monitoring and actions taken in real time. Many organizations underestimate the impact of power quality damage, which speaking about time of unplanned non-operation, lost production, lost data and premature equipment damage, it can be significant. The problems also lead to big invoices for electricity and even penalties for “pollution” of power supply network. To check the framing within admitted limits, acoustically speaking, an experimental research was started on the level of acoustic pressure produced during operation of the installation. Considering the installation for bio-stimulant obtaining is using vegetal waste as raw material, during their chopping stage and transport to the bin intended for maceration there is the possibility of releasing a quantity of fine powders into internal atmosphere. Under these circumstances, this study is checking the framing within admitted limits, required by laws, of the concentration of powders released into atmosphere during operation of an installation that produces vegetal bio-stimulants from after-cropping agricultural waste and medicinal herbs.

Integrating Ecosystem and Urban Services in Policy-Making at the Local Scale: The SOFA Framework

Despite ecosystem services having been broadly studied in the scientific literature, they are still hardly integrated in policy-making and landscape management. The lack of operative tools for their application is a main limiting factor of such operationalization. In this work, a framework including 53 livability services produced by the biophysical and socioeconomic subsystem, or by their interaction, was developed considering a local study area. All the services were characterized in terms of the need to access their Service Benefiting Areas (SBAs, the geographical units where the services benefit consumers) from the Use Regions (URs, the usual location of users). Moreover, the Service-Providing Areas (SPAs, the geographical unit where the service is produced) were also classified and characterized. Such analysis, together with empirical observations, helped to classify the spatial relationships between the SPAs, SBAs and URs of each service. In addition to a list of detailed information about all the services included in the framework, a visual scheme representing the different SBA types and an operational flow diagram synthesizing the spatial organization of service flow were designed to apply the methodology in other study areas. Two examples show the practical applicability in policy-making of the whole framework for supporting different aspects of local decision-making.

Retrospective audit of patients referred for further treatment following Mohs surgery for non-melanoma skin cancer.

To describe the characteristics, subsequent management and outcomes of patients referred for further management following Mohs micrographic surgery (MMS) for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Retrospective analysis of patients referred to a quaternary cancer centre from 2000 to 2015. In total, 83 lesions in 82 patients were referred for further management; 52 (62%) were SCC and 80 (96%) were located in the head and neck. Reasons for referral included high-risk disease for consideration for adjuvant radiotherapy (37/83, 45%), inadequate resection (28/83, 34%) or recurrence following previous MMS (15/83, 17%). Fewer than 40% of the 69 referrals received from MMS surgeons included photos or an operative report and diagram. There was discordance in pathology opinion in 11 (13%) of cases. Histopathology from MMS was reviewed in eight cases and there was discordance with the in-hospital pathology opinion in six of these. In-hospital re-excision was performed in 19 cases and in five of these the pathology report on the paraffin-sectioned re-excised tissue was discordant with prior MMS assessment. Significantly, two cases were associated with a misinterpretation of lymphocytic infiltrate as residual disease in patients with chronic lymphocytic leukaemia (CLL). This study highlights some of the challenges and limitations of MMS. Early referral for multidisciplinary management is recommended when MMS resection margins are inadequate or uncertain, especially for high-risk SCC. We recommend that referrals be accompanied by histological material, as well as a detailed report with operative photos and diagrams. CLL can pose an intraoperative diagnostic challenge. Discrepancies in the interpretation of MMS slides present an opportunity for improvement, and our findings support the role of ongoing quality assurance programs.

Seadrome: Technologies of Complex Navigation for Amphibious Unmanned Aerial Vehicles in the Seaplane Basin

The paper considers the physical principles of operation, performance and structural diagram of the short base sonar navigation system installed aboard an amphibious unmanned aerial vehicle. This system provides the required course piloting in the seaplane basin that is assigned by the network system of bottom transmitter-receiver antenna assemblies.

Increasing the Energy Efficiency of the Cyclic Action Mechanisms in Rolling for a Roller Bed Used as an Example

The possibility of increasing the energy efficiency of the production cycle in a roller bed is briefly reviewed and justified. The sequence diagram of operation of the electrical drive in a roller bed is analyzed, and the possible increase in the energy efficiency is calculated. A method for energy saving is described for the application of a frequency-controlled asynchronous electrical drive of drive rollers in a roller bed with an increased capacitor capacity in a dc link. A fine mathematical model is developed to describe the behavior of the electrical drive during the deceleration of a roller bed. An experimental setup is created and computer simulation and physical modeling are performed. The basic information flows of the general hierarchical automatic control system of an enterprise are described and determined with allowance for the proposed method of increasing the energy efficiency.

Targeted poly(3-hydroxybutyrate-co-3-hydroxyvalerate) bioplastic production from carbon dioxide

A microbial production process was developed to convert CO2 and valeric acid into tailored poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) bioplastics. The aim was to understand microbial PHBV production in mixotrophic conditions and to control the monomer distribution in the polymer. Continuous sparging of CO2 with pulse and pH-stat feeding of valeric acid were evaluated to produce PHBV copolyesters with predefined properties. The desired random monomer distribution was obtained by limiting the valeric acid concentration (below 1 gL-1). 1H-NMR, 13C-NMR and chromatographic analysis of the PHBV copolymer confirmed both the monomer distribution and the 3-hydroxyvalerate (3HV) fraction in the produced PHBV. A physical-based model was developed for mixotrophic PHBV production, which was calibrated and validated with independent experimental datasets. To produce PHBV with a predefined 3HV fraction, an operating diagram was constructed. This tool was able to predict the 3HV fraction with a very good accuracy (2% deviation).

Thermal Neutralization Of Excessive Heat Transfer Agent In Coke Dry-Quenching Plants (CDQP)

The paper considers the problem of reducing emissions of harmful substances in the process of coke dry quenching. It proposes an option for thermal neutralization of excessive heat transfer agent in the coke dry-quenching plants as well as preheating of heat transfer agent and air by exhaust combustion products. The paper presents a process diagram and main process parameters of plant operation. It shows efficient recovery of secondary energy resources in the form of chemical heat in the proposed plant.

The use of operational event sequence diagrams and work domain analysis techniques for the specification of the crewing configuration of a single-pilot commercial aircraft

Aircraft manufacturers and avionics systems suppliers are developing technologies for airliners that will be operated by just a single crew member. An alternative approach to using a large amount of on-board computing proposes the utilisation of extant technology derived from single-seat military aircraft and Uninhabited Air Systems where control is distributed in real time across the aircraft flight deck and ground stations (which supervise several aircraft simultaneously). Using a combination of operational event sequence diagrams and work domain analysis techniques, the allocation of tasks and requirements for the development of supporting technologies for such an operational architecture are identified in a low visibility taxi scenario. These analyses show that many of the functions undertaken by a second pilot in this situation are associated with checking, surveillance and monitoring activities. These must be undertaken either by automated aircraft systems or the monitoring personnel in the ground station. This analytical approach can successfully provide the necessary information underpinning the design requirements for such an aircraft concept.

Wrinkling instability of an inhomogeneously stretched viscous sheet

Motivated by the redrawing of hot glass into thin sheets, we investigate the shape and stability of a thin viscous sheet that is inhomogeneously stretched in an imposed non-uniform temperature field. We first determine the associated base flow by solving the long-timescale stretching flow of a flat sheet as a function of two dimensionless parameters: the normalized stretching velocity $\alpha$, and a dimensionless width of the heating zone $\beta$. This allows us to determine the conditions for the onset of an out-of-plane wrinkling instability stated in terms of an eigenvalue problem for a linear partial differential equation governing the displacement of the midsurface of the sheet. We show the sheet can become unstable in two regions that are upstream and downstream of the heating zone where the minimum in-plane stress is negative. This yields the shape and growth rates of the most unstable buckling mode in both regions for various values of the stretching velocity and heating zone width. A transition from stationary to oscillatory unstable modes is found in the upstream region with increasing $\beta$ while the downstream region is always stationary. We show that the wrinkling instability can be entirely suppressed when the surface tension is large enough relative to the magnitude of the in-plane stress. Finally, we present an operating diagram that indicates regions of the parameter space that result in a required outlet sheet thickness upon stretching, while simultaneously minimizing or suppressing the out-of-plane buckling; a result that is relevant for the glass redraw method used to create ultrathin glass sheets.

ТЕНДЕНЦИИ РАЗВИТИЯ ГЕЛИОЭНЕРГЕТИЧЕСКОЙ ТЕХНИКИ: ТЕРМОТРАНСФОРМАТОРЫ «СУХОЙ» АБСОРБЦИИ ДЛЯ СИСТЕМ ПРИРОДООБУСТРОЙСТВА

The article deals with solar energy thermotransformers for heat and cold production in the most favorable climatic zones of Russia. The authors give examples of solar energy cyclic thermotransformers operating in working pairs, which are widely used due to very good sorption qualities (alkaline earth salts CaCl2 and SrCl2 (sorbates) and ammonia (refrigerant)). There have been described three main trends in increasing thermotransformers efficiency: using pure sorbents with powder graphite admixture (with growing portion of admixtures heat conductivity ratio increases in SrCl2 to 1.3 times, in CaCl2 ≈ to 4 times); painting insolated surfaces of the thermotransformers with selective coating (working efficiency of such surfaces is 1.8-2 times higher compared to surfaces covered with matt black painting, operational and aesthetic properties of the surface); improving structures of both reactors in absorber-generators, and installations. In the climatic conditions of the Astrakhan Region there have been carried out check studies of a new type of autonomous thermotransformer in a working pair CaCl2 - NH3. There are shown graphs of temperature changes in the plant apparatuses in daily working time: maximum daily temperature of absorber-generator is 120°C, at night - 70°C; recorded minimum temperature was -15°C. The authors state that heat is possible to receive 24 hours a day. Application of such thermotransformers is patented for thermal water treatment plants used for hydrobionts cultivation. The article presents the diagram of operation of a thermotransformer powered from renewable energy sources (solar and wind energy)

Flow transition criteria of a liquid jet into a liquid pool

To better understand the fundamental interactions between melt jet and coolant during a core-disruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquid-gas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation.

A density-dependent model of competition for one resource in the chemostat

This paper deals with a two-microbial species model in competition for a single-resource in the chemostat including general intra- and interspecific density-dependent growth rates with distinct removal rates for each species. In order to understand the effects of intra- and interspecific interference, this general model is first studied by determining the conditions of existence and local stability of steady states.With the same removal rate, the model can be reduced to a planar system and then the global stability results for each steady state are derived. The bifurcations of steady states according to interspecific interference parameters are analyzed in a particular case of density-dependent growth rates which are usually used in the literature.The operating diagrams show how the model behaves by varying the operating parameters and illustrate the effect of the intra- and interspecific interference on the disappearance of coexistence region and the occurrence of bi-stability region. Concerning the small enough interspecific interference terms, we would shed light on the global convergence towards the coexistence steady state for any positive initial condition. When the interspecific interference pressure is large enough this system exhibits bi-stability where the issue of the competition depends on the initial condition.

Methane steam reforming thermally coupled with catalytic combustion in catalytic microreactors for hydrogen production

Growing interest in small-scale, portable energy devices has necessitated the development of micro-scale fuel processing systems. Steam reforming of methane coupled with methane catalytic combustion in catalytic microreactors for hydrogen production was studied, using a two-dimensional computational fluid dynamics (CFD) model with detailed chemistry and transport. The effect of channel height, inlet steam-to-carbon ratio, wall thermal conductivity, catalyst, and flow rate were explored to provide guidelines for optimal design. Operating diagrams were constructed, and different operating lines were mapped out. It was shown that stable and efficient reactor operation is feasible at millisecond contact times with high conversion, but very careful design is crucial in achieving this. The steam reforming process is kinetically-controlled, whereas the catalytic combustion process is mixed kinetically/transport-controlled. For system design, the dimensions of the combustion channel must be picked to minimize transfer limitations. Operation at lower inlet steam-to-carbon ratio increases the power output at lower temperatures. The construction materials depend on the overall system optimization. Low-conductivity materials allow higher conversions and power outputs at the expense of hot spots, and moderate-conductivity materials make a good compromise between conversion and temperature. Furthermore, a performance comparison of rhodium and nickel suggested that it is vital to select the reforming catalyst. Finally, a simple operation strategy was proposed for obtaining maximum thermal efficiency, ensuring high conversions and reasonable wall isothermicity.