Idle Mode Research Articles

A deterministic fluid model for production and energy mode control of a single machine

Improving machines’ energy efficiency through dynamic energy mode control to meet demand requirements with minimal energy consumption is a promising approach. This study considers a machine operating in working, idle, off, and warmup energy modes with different energy consumption in each mode. A deterministic fluid model is developed to analyze an energy mode control policy that determines when to keep the machine working, off or idle, and switch to other modes based on the inventory/backlog level to minimize the total energy, inventory, and backlog costs. This approach facilitates the derivation of closed-form expressions for the optimal thresholds and the associated costs. This modeling approach allows us to prove that a policy that operates the machine between the working and off modes or the working and idle modes is always better than a hybrid policy that operates the machine in working, off, and idle modes simultaneously. We use the solution of the deterministic fluid model to propose an approximate policy for machines with stochastic production, warmup, and demand processes. We compare the results of the proposed approximation method with the optimal solution of a stochastic system where the production and warmup times are exponential and the demand inter-arrival times have Erlang distribution. The optimal solution for the stochastic system is determined by solving a Markovian Decision Process (MDP). Our numerical experiments show that the proposed approximation method predicts the optimal policy type for the stochastic case with a 89.3% accuracy, and the average error between the optimal cost and the cost obtained with the approximation method is 1.37% for 729 different cases tested. Furthermore, the computational efficiency of the proposed approximation is around 250 times better than the effort to determine the optimal policy using an MDP approach. We propose this approximation method where the control parameters are given in closed form as an easy-to-implement and effective policy to control energy modes to minimize the total energy, inventory, and backlog costs. Furthermore, we present the deterministic fluid modeling approach as a versatile approach to analyze energy mode control problems.

Local Load Migration in High-Capacity Fog Computing

Fog computing brings storage and computational capabilities closer to the data source, which reduces latency and enhances efficiency in processing data. However, these capabilities are resource-constrained at the fog nodes as compared to the cloud core. This limitation can result in high computational loads that yield in saturation and congestion at the fog nodes when processing large traffic volumes. Hence, this paper introduces a novel load migration scheme for delay-sensitive and computation-intensive requests in fog computing without relaying to the cloud core, thus avoiding prolonged link delays. First, a grouped service function chain (SFC) provisioning framework is embedded on a heterogeneous architecture composed of super fog (SF) and ordinary fog (OF) nodes, where all the virtual network functions (VNFs) in the SFC are mapped on a single SF node to reduce resource use. Here, the SF nodes are always in active mode to receive incoming traffic, whereas the OF nodes are maintained in idle mode to save power and computing resources. When the SF node approaches a saturation threshold alarm, it diffuses its load (hosted VNFs) gradually to neighboring OF nodes in the vicinity, thus avoiding saturation at the SF node and providing service continuity. The framework is implemented on a resource-constrained network to achieve realistic operating conditions. Overall, the proposed work achieves high admission and resource utilization rates, reduced delays, and power consumption, as compared to key network architectures and provisioning schemes that separately map delay-sensitive and computation-intensive on hierarchical fog layers, which incur increased delays, network traffic, and power usage.

Characteristics of Activated Carbon Panels in Reducing CO, NO2, HC, Pb, and Noise

Increasing population growth has resulted in increased vehicle ownership and the need for parking facilities, including in basements. This study aimed to explore the efficacy of palm shell activated carbon panels in reducing CO, NO2, HC, Pb, and noise. The experiment was conducted in a 4 m x 3 m x 2.1 m room using three treatments: without installed activated carbon panels; with 1 cm x 20 cm x 20 cm activated carbon panels; and with 2 cm x 20 cm x 20 cm activated carbon panels. During the measurement, three motorcycles were turned on and kept in idle mode. The concentrations of CO, NO2, HC, ambient Pb, and noise were measured. The results showed that the activated carbon panels were able to reduce CO, NO2, Pb, HC, and noise. The highest performance was obtained for 2-cm thickness of activated carbon panels, with CO, NO2, HC, Pb, and noise decreasing to 824 µg/m3, 8.4 µg/m3, 4.4 µg/m3, 0.2 µg/m3, and 87.44 dB, respectively. Following the adsorption process, the carbon content and pore size of the activated carbon panels had changed from 68.32% to 90.95% and 0.17-3.652 µm to 0.34-5.56 µm respectively for testing with 2-cm thickness panels.

A semi-automatic analytical methodology for characterizing the energy consumption of MRI systems using load duration curves.

Magnetic resonance imaging (MRI) scanners are a major contributor to greenhouse gas emissions from the healthcare sector, and efforts to improve energy efficiency and reduce energy consumption rely on quantification of the characteristics of energy consumption. The purpose of this work was to develop a semi-automatic analytical methodology for the characterization of the energy consumption of MRI systems using only the load duration curve (LDC). LDCs are a fundamental tool used across various fields to analyze and understand the behavior of loads over time. An electric current transformer sensor and data logger were installed on two 3T MRI scanners from two vendors, termed M1 (outpatient scanner) and M2 (inpatient/emergency scanner). Data was collected for 1 month (7/11/2023 to 8/11/2023). Active power was calculated, assuming a balanced three-phase system, using the average current measured across all three phases, a 480V reference voltage for both machines, and vendor-provided power factors. An LDC was constructed for each system by sorting the active power values in descending order and computing the cumulative time (in units of percentage) for each data point. The first derivative of the LDC was then computed (LDC'), smoothed by convolution with a window function (sLDC'), and used to detect transitions between different system modes including (in descending power levels): scan, prepared-to-scan, idle, low-power, and off. The final, segmented LDC was used to measure time (% total time), total energy (kWh), and mean power (kW) for each system mode on both scanners. The method was validated by comparing mean power values, computed using the segmented 1-month LDC, for each nonproductive system mode (i.e., prepared-to-scan, idle, lower-power, and off) against power levels measured after a deliberate system shutdown was performed for each scanner (1 day worth of data). The validation revealed differences in mean power values<1.4% for all nonproductive modes and both scanners. In the scan system mode, the mean power values ranged from 29.8 to 37.2kW and the total energy consumed for 1 month ranged from 11106 to 14466kWh depending on the scanner. Over the course of 1 month, the portion of time the scanners were in nonproductive modes ranged from 76% to 80% across scanners and the nonproductive energy consumption ranged from 8010 to 6722kWh depending on the scanner. The M1 (outpatient) scanner consumed 99.9 and 183.9kWh/day in idle mode for weekdays and weekends, respectively, because the scanner spent 23% more time proportionally in idle mode on the weekends. A semi-automatic method for quantifying energy consumption characteristics of MRI scanners was introduced and validated. This method is relatively simple to implement as it requires only power data from the scanners and avoids the technical challenges associated with extracting and processing scanner log files. The methodology enables quantitative evaluation of the power, time, and energy characteristics of MRI scanners in scan and nonproductive system modes, providing baseline data and the capability of identifying potential opportunities for enhancing the energy efficiency of MRI scanners.

Wind Power Station Efficiency Increase Methods Based on Wind Turbine Condition Process Mathematical Modelling when Distributing Electric Power Between the Consumers in Arctic and Far North Regions

The relevance of wind power plant efficient control method based on wind turbine condition process mathematical modeling is proved for electric power distribution between consumers, intended to minimize decision-making time on technological process redistribution of electric power production for another consumer by means of actual information on equipment failure time (wind turbine, electric power stocking system), that provides optimum power production and consumption planning in northern regions. The review of the basic mathematical modeling methods of electric power redistribution between consumers that showed there are certain problem statements with insufficient descriptions of mathematical models or the absence of ready and effective methods to solve them, in particular, wind turbine condition process mathematical modeling for electric power distribution to consumers in northern regions. As a result of the analysis of wind power plant efficient control method on the basis of wind turbine condition process mathematical modeling to distribute electric power to consumers in northern regions game theory and pulse system functioning mathematical methods application based on difference equations is expedient. The decision-making strategies stipulated by 'nature' (working capacity or wind turbine failure), the scheduler (repair or wind turbine redistribution) and a condition of phase co-ordinate (repair, idle, redistribution or operation wind turbine modes) are defined. On the basis of the accepted strategy and use of step function Heaviside F(t) for fixing of technological process time, the description of the wind turbine condition equation was made providing operative failure time information access on because due to idle time, redistribution or repair that provides optimum electric power production planning for a consumer.

Determining the Idle Mode of the Last Stages of Powerful Steam Turbines for Wet Steam Area

Determining the Idle Mode of the Last Stages of Powerful Steam Turbines for Wet Steam Area

Spatial distribution and policy implications of the exhaust emissions of two-stroke motorcycle taxis: a case study of southwestern state in Nigeria

Two-stroke motorcycles emit harmful exhaust fumes because of incomplete combustion. Although they constitute the main fleet of motorcycle taxis in sub-Saharan Africa, monitoring, spatial assessment, and regulation are weak, leaving dire health consequences in cities. This study collected motorcycle raw exhaust emissions of 1,950 two-stroke petrol-driven motorcycle taxis, otherwise called okada, in Ogun State, Nigeria, using an idle mode test approach under 10 minutes and employed correlations, hierarchical multiple linear regression models, and spatial analysis. It was found that carbon monoxide (CO) and hydrocarbons (HC) were the most highly concentrated, and the latter were beyond allowable limits. The concentration of CO was found to be at the minimum of 0.00 % and the highest being at 6.40% (an average of 1.05%), while the HC concentration was reported at the minimum of 18.00 ppm and the highest at 15446 ppm (an average of 3560 ppm). Notably, Kriging interpolation analysis indicated that cumulative effects due to the clustering and operations of motorcycle taxis could increase these concentrations over time, extending their long-term impacts. Given the severe effects of these emissions on health and the wider environment, a DPSIR policy framework is proposed to regulate two-stroke motorcycle taxis in sub-Saharan Africa.

ДОСЛІДЖЕННЯ ЕЛЕКТРОМАГНІТНИХ ТА МЕХАНІЧНИХ ПРОЦЕСІВ АСИНХРОННО-СИНХРОННОГО ЕЛЕКТРОМЕХАНІЧНОГО ПЕРЕТВОРЮВАЧА В РЕЖИМІ НЕРОБОЧОГО ХОДУ

A two-dimensional circuit-field model of non-stationary electromagnetic and mechanical processes of an induction-synchronous electromechanical converter has been developed. It allows establishing the relationship between electro-magnetic processes in the circuit and 2D-field parts of the model, taking into account the features of the construction of its armature and rotor windings through their schematic implementation, and ensuring switching with elements of con-ventional and semiconductor power systems. Electromagnetic and mechanical processes in idle mode have been inves-tigated using numerical modeling methods, considering the combined interaction of the coupled induction and synchro-nous parts in a single active part of the electromechanical converters. The presence of self-synchronization properties for induction -synchronous electromechanical converters has been demonstrated, wherein asynchronous starting is provided with subsequent synchronization of its rotor into synchronism in idle mode without excitation, and the condi-tions for their occurrence are explained. The relationships between the idle current and excitation current have been established, determining the operation of the synchronous part of the induction-synchronous electromechanical con-verter in underexcited, normally excited, and overexcited modes. It has been proven that in underexcited and normally excited modes, its synchronous part operates as a reactive power compensator, while in the overexcited mode, it oper-ates as a generator. Experimental studies confirm the adequacy and accuracy of numerical implementation, as well as the correspondence to electromagnetic processes during the operation of the induction-synchronous electromechanical converter in idle mode. References 14, figures 11.

Interventional Imaging Systems in Radiology, Cardiology, and Urology: Energy Consumption, Carbon Emissions, and Electricity Costs.

BACKGROUND. The energy demand of interventional imaging systems has historically been estimated using manufacturer-provided specifications rather than directly measured. OBJECTIVE. The purpose of this study was to investigate the energy consumption of interventional imaging systems and estimate potential savings in the carbon emissions and electricity costs of such systems through hypothetical operational adjustments. METHODS. An interventional radiology suite, neurointerventional suite, radiology fluoroscopy unit, two cardiology laboratories, and two urology fluoroscopy units were equipped with power sensors. Power measurement logs were extracted for a single 4-week period for each radiology and cardiology system (all between June 1, 2022, and November 28, 2022) and for the 2-week period from July 31, 2023, to August 13, 2023, for each urology system. Power statuses, procedure time stamps, and fluoroscopy times were extracted from various sources. System activity was divided into off, idle (no patient in room), active (patient in room for procedure), and net-imaging (active fluoroscopic image acquisition) states. Projected annual energy consumption was calculated. Potential annual savings in carbon emissions and electricity costs through hypothetical operational adjustments were estimated using published values for Switzerland. RESULTS. Across the seven systems, the mean power draw was 0.3-1.1, 0.7-7.4, 0.9-7.6, and 1.9-12.5 kW in the off, idle, active, and net-imaging states, respectively. Across systems, the off state, in comparison with the idle state, showed a decrease in the mean power draw of 0.2-6.9 kW (relative decrease, 22.2-93.2%). The systems had a combined projected annual energy consumption of 115,684 kWh (range, 3646-26,576 kWh per system). The systems' combined projected energy consumption occurring outside the net-imaging state accounted for 93.3% (107,978/115,684 kWh) of projected total energy consumption (range, 89.2-99.4% per system). A hypothetical operational adjustment whereby all systems would be switched from the idle state to the off state overnight and on weekends (versus being operated in idle mode 24 hours a day, 7 days a week) would yield the following potential annual savings: for energy consumption, 144,640 kWh; for carbon emissions, 18.6 metric tons of CO2 equivalent; and for electricity costs, US$37,896. CONCLUSION. Interventional imaging systems are energy intensive, having high consumption outside of image acquisition periods. CLINICAL IMPACT. Strategic operational adjustments (e.g., powering down idle systems) can substantially decrease the carbon emissions and electricity costs of interventional imaging systems.

The investigation of diesel soot emission using instrument combination of multi-wavelength photoacoustic spectroscopy and scanning mobility particle sizer

The parallel measurements of wavelength dependent optical absorption, particle number size distribution have made by a multi wavelength photoacoustic spectrometer (4λ-PAS) and scanning mobility particle sizer (SMPS) respectively at different modes of a diesel engine using two different types of fuel. The thermal evolution of the emission was also investigated using posterior temperature treatment of emission. The bimodal size distribution of emitted particles at a set reference temperature has been observed regardless of the applied fuel at idle. However, the emitted particulate assembly had lognormal size distribution falls into the accumulation mode at all other defined engine modes and both fuel types. The total number- and volume concentration (TNC and TVC) showed retrograde tendency with the increasing torque and rpm independently of the applied fuel types. The TNC values decreased up to 50% for both fuels with engine operation changes from idle engine mode(em#1) to low engine mode(em#2). With further increase in torque and rpm of engine, the change in TNC is negligible. On the other hand, the TVC remains more or less the same for idle to low engine mode transition and increased more than 60% for high mode (em#3) transition. The Optical Absorption Coefficient (OAC) values measured at the operational wavelengths of the 4λ-PAS instrument decreased at all wavelengths with increasing rpm and torque. The wavelength dependency quantified by Aerosol Ängström Exponent (AAE) was applied here for qualitative analysis of the carbonaceous emission and showed decreased values towards the higher engine speed and torque output of the engine. The proposed technique can be used as real-time, precise and accurate measurement of light absorption by DPM aerosols, which opens up novel possibilities for the volatility and thermal evolution investigation of diesel emissions.

Improving the Energy Efficiency of Machine Tools using a Thermal Storage Unit based on a Phase Change Material

Today there are many ideas investigated to find ways for industries to become more environmentally friendly and sustainable. To reduce the energy consumption of machine tools and thus increase the efficiency of production, this paper discusses the idea of a heat accumulator based on a phase change material (PCM). In the context of biologisation in production technology, this work is based on the principle of heat storage in equi-warm organisms.Since machine tools deform under thermal influences and thus affect the machining process, they are often operated in idle mode before the work process to reach a thermally stable state and reduce thermally induced deformation during the production process. The machine is actively tempered using the cooling circuit to keep the temperature plateau constant.The idea of the PCM unit presented in this paper is to store this excess and otherwise dissipated energy. This can be used before the machines next process cycle to induce heat into the machine and reach the stable temperature plateau without operating the machine. The conditions under which the energy consumption can be reduced using this method and thus making the operation more sustainable are discussed and first simulations show that the goal is achievable.

Characterizing ActiGraph's Idle Sleep Mode in Free-living Assessments of Physical Behavior.

ActiGraph’s idle sleep mode (ISM) is an optional battery- and memory-conserving feature believed to engage during periods of nonwear, inactivity, and sleep, but it has not been well studied in free-living environments. Thus, we investigated ISM during a 7-day assessment in a nationally representative sample of 13,649 participants (6–80 years) in the United States and found it engaged 43.6% ± 0.2% (mean ± SE) of the 24 hr per day. ISM engagement was highest (78.4% ± 0.2%) during early morning (00:00–05:59) and lowest (20.4% ± 0.3%) during afternoon (12:00–17:59), corresponding to quadrants of lowest and highest of movement, respectively. ISM engagement was also inversely correlated with daily activity across all participants (R = −.72, p &lt; .001). When restricted to participants averaging ≥21 hr per day of wear (N = 10,482), ISM still engaged 39.5% ± 0.2% of the day and inversely correlated to daily activity (R = −.58, p &lt; .001). These results suggest ISM engages in activity level-dependent temporal patterns. Additional research is needed to better inform analyses and interpretation of ISM-enabled data including whether it is appropriate to process them with existing methods that were developed and validated using data without ISM enabled. This issue may be particularly relevant for methods used to detect and score sleep, as ISM engaged during a substantial portion of the typical overnight sleep period in the 8-hr window between ≥22:00 and &lt;06:00 (74.0% ± 12.6%, mean ± SD).

Wireless Charging Techniques for New Energy Vehicles

Auto Wireless Billing is an easy and quick way to charge an electric or plug-in hybrid car. The car will be able to use wireless charging at any time, without having to connect to it. In extreme cold weather, the electric vehicles (EVs) will probably be buried in the snow and ice and will not be usable. But the wireless billing technique is able to satisfy the demand of all kinds of weather. Aside from recharging during idle mode, wireless charging also offers a potential for dynamic charging - enabling the car to be recharged as it travels. Once this technique is developed, it will be able to solve the problem of EV's running range. Therefore, it is possible to lower the load of EV, lower the cost of EV, and increase the quantity of EV. In this paper, various wireless charging technologies for EV are discussed and analyzed. Also, the optimization strategies will be given as future perspectives.

Energy-efficient production control of a make-to-stock system with buffer- and time-based policies

Increasing energy efficiency in manufacturing has significant environmental and cost benefits. Turning on or off a machine dynamically while considering the production rate requirements can offer substantial energy savings. In this work, we examine the optimal policies to control production and turn on and off a machine that operates in working, idle, off, and warmup modes for the case where demand inter-arrival, production, and warmup times have phase-type distributions. The optimal control problem that minimises the expected costs associated with the energy usage in different energy modes and the inventory and backlog costs is solved using a linear program associated with the underlying Markov Decision Process. We also present a matrix-geometric method to evaluate the steady-state performance of the system under a given threshold control policy. We show that when the inter-arrival time distribution is not exponential, the optimal control policy depends on both the current phase of the inter-arrival time and inventory position. The phase-dependent policy implemented by estimating the current phase based on the time elapsed since the last arrival yields a buffer- and time-based policy to control the energy mode and production. We show that policies that only use the inventory position information can be effective if the control parameters are chosen appropriately. However, the control policies that use both the inventory and time information further improve the performance.

Determination of dynamic component reactions in support bearings of rotor saws for cutting hot rolled (message 1)

A distinctive feature of rotary saws is the process of cutting the workpiece, which takes a very short time. For example, a workpiece with a diameter of 200 mm is cut in 0.2 seconds, while traditional designs of sliding and pendulum saws perform this operation in 10-20 seconds or more. This effect is achieved due to the high speeds of feeding the disc to the cut, exceeding traditional modes by 20 or more times. However, due to the specific cutting conditions, weak links were identified in these designs that require further improvement. One of the factors that reduces the reliability of the saw is the insufficient durability of the bearings of the high-speed disk shaft, which perceives the cutting force. Until now, the reliability issues of rotary saw structures remained unresolved. One of the factors that reduces the reliability of the saw is the insufficient durability of the bearings of the high-speed disk shaft, which perceives the cutting forces. Practice shows that the applied methods of calculating the strength of support bearings do not allow taking into account all possible factors that affect the reliability of bearings in the cutting process. First of all, as it turned out, during operation, the saw blade has radial runout, possibly due to an error when cutting the teeth of the blade and the eccentric landing of the blade on the seat when replacing it. For modern rolling mill production, the issue of strength and reliability of rotary saw designs, which are intended for cutting rolled metal, is relevant. The purpose of this work is to determine the precise values of the reaction forces of the support bearings of the disc shaft. As you know, during long-term operation of the object, the place for landing the cutting disc on the faceplate wears out, sometimes there is an error in the hole when making a new disc. Therefore, there is an eccentricity of the center of gravity of the disk. The presence of this eccentricity is taken into account in the work when determining the required forces using D'Alembert's principle of conditional balancing of forces. Due to the fact that the process of cutting with a circular saw is very short-term, the cutting force is considered the impact force. The magnitudes of the reaction forces in the bearings are determined during cutting using the impact dynamics theorems: the momentum theorem and the kinetic momentum change theorem. By projecting the vector formulas of the principle and theorems on the coordinate axis, the systems of algebraic equations are obtained, from which the horizontal and vertical components of the reaction forces in the bearings are determined both in idle mode and during cutting. Due to the fact that the vector of the centrifugal Dalembert force of inertia of the disk changes its direction, the formulas of the reaction forces at different positions of the center of gravity of the disk were obtained. According to the results of the planned numerical analysis of the problem, graphs of the dependences of the horizontal and vertical components of the pressure forces on the bearings can be drawn from: the eccentricity value, the vertical and horizontal components of the cutting forces, the angular velocity and the position of the disk

Mathematical Modeling State Analysis of Multifunctional Energy Converters with a Solid Rotor

Multifunctional energy converters (MFEC) are induction motors with an external hollow solid rotor. Structurally, the MFEC is an electric machine in which the stator has the appearance of a conventional winding rotor and is located in a steel tube, which performs the functions of the rotor. In normal use for an electric motor, this design is inefficient due to significant losses in the solid rotor due to eddy currents. In the case of the MFEC, all losses go to the heating of the loose material that moves along the surface of the solid rotor, so the efficiency of the MFEC is very high. The non-standard design of the MFEC raises a number of questions regarding the calculation of such an electric machine and the mathematical modeling of transient modes: start-up in idle mode, start-up under load, operation during long-term parking under current, random load change during operation, etc. The complexity is caused by taking into account the given parameters of the solid rotor during the change of slip and currents. On the one hand, the currents in the rotor affect the parameters of the solid rotor, on the other hand, these currents cannot be calculated without determining the parameters of the rotor. In this regard, this paper aims to reveal problematic issues in mathematical modeling of transient modes of MFEC with a solid rotor and create a basis for further research in this direction.

INCREASE IN THE FUEL EFFICIENCY OF A DIESEL ENGINE BY DISCONNECTING SOME OF ITS CYLINDERS

In fuel economy, a rising level of interest in heavy duty diesel engines that industry has witnessed over the last few years continues to go up and this is not likely to change. Lowering the fuel consumption of all internal combustion engines remains a priority for years to come, driven by economic, legislative, and environmental reasons. According to statistics, the share of operating expenses to ensure transport operations in industrial production is 15-20%, wherein 16-30% of the total volume of transport operations concerns a car, tractor, and trailer. During transport operations, the engine load by the torque, in most cases, does not exceed 40-50%. The paper investigates the increase in fuel efficiency of cars and tractors by disconnecting some of the engine cylinders operated in low-load and idling modes. The research has led to the establishment of the theoretical dependencies between the effective power, engine efficiency, mass of the transported cargo, speed of the car (tractor) and the number of disconnected engine cylinders. Results of experiments suggest the interdependencies of the performance parameters of the car (tractor) when disconnecting some of the engine cylinders. It has also been established that the maximum reduction in the hourly fuel consumption occurs in the idling mode while it decreases along with an increase in the load.

Greenhouse gas emissions reduction and energy savings for a dredger at port area using hybrid photovoltaic power system onboard

For reducing greenhouse gas (GHG) emission and saving energy, a hybrid photovoltaic (PV) energy system comprised of grid-connect and off-grid modes was utilized on a dredger at emission control area (ECA) such as a port area. The experiments on this hybrid PV power system were carried out to evaluate the electric energy consumption of each equipment onboard in three operation modes (dredging, rest and idle) of dredger and to analyze the contribution of such a PV power system. The PV array had charging batteries in grid-connect mode and converted the PV power to alternating current (AC) directly during daytime period. At nighttime, the batteries could supply the electric power in off-grid mode. Even this dredger is no large free deck area for installing PV arrays onboard, the power conversion for PV array can offer about 1.0 % of total demand electric energy yearly. After evaluating the electric power consumption of each equipment onboard at different dredger operation mode, the proposed hybrid PV power system can offer 4.0 % (3.9 kWh by 96.8 kWh) of energy demand in grid-connect at rest mode and supply 100 % (29.85 kWh by 29.85 kWh) energy for dredger equipment in off-grid without diesel generator running at idle mode. This hybrid PV power system on the dredger has not only saved marine diesel oil (MDO) 2094.2 kg/year, reduced GHG of CO2 about 6455 kg/year, SOx about 3.942 kg/year and particulate matter (PM) around 1.97 kg/year but also reduced the diesel generator maintenance cost from stop running for 15 h/day and saved the cost of fuel (MDO) about USD 2128.5/year. The hybrid PV power system exhibited very effective efficiency of PV array and optimized the installation of batteries bank in ship with limited deck space at ECA and port area with high solar radiation density zone.

Energy consumption in MRI: Determinants and management options

BackgroundEnergy consumption awareness is a known concern, and radiology departments have energy-intensive consuming machines. The means of energy consumption management in MRI scanners have yet to be evaluated. PurposeTo measure the MRI energy consumption and to evaluate the means to reduce it. Materials and methodsData was retrieved for two MRI scanners through the hospital's automated energy consumption measurement software. After correlation with picture archiving and communication system (PACS) files, they were segmented by machine and mode (as follows: stand-by, idle and active) and analyzed. Active mode data for a specific brain MRI protocol have been isolated, and equivalent low energy consuming protocol was made. Both were performed on phantom and compared. Same protocol was performed on a phantom using 3.0T 16 and 32 head channels coils. Multiples sequences were acquired on phantom to evaluate power consumption. ResultsStand-by mode accounted for 60 % of machine time and 40 % of energy consumption, active mode accounted for 20 % machine time and 40 % energy consumption, idle mode for 20 % imachine time and 20 % consumption. DWI and TOF sequences were the most consuming in our brain-MRI protocol. The low energy consuming protocol allowed a saving of approximately 10 % of energy consumption, which amounted for 0.20€ for each examination. This difference was mainly due to an energy consumption reduction of the DWI sequence. There were no difference in consumption between a 3.0T 16 and 32 channels head coils. Sequence's active power and duration (especially considering slice thickness) have to be taken into account when trying to optimize energy consumption. ConclusionThere are two key factors to consider when trying to reduce MRI scan energy consumption. Stand-by mode energy consumption has to be taken into account when choosing an MRI scan, as it can't be changed further on. Active mode energy consumption is dependent of the MRI protocols used, and can be reduced with sequences adaptation, which must take into account sequence's active power and duration, on top of image quality.

Experimental Studies of Engine Crankcase Gas Consumption D-243 With Varying Degrees of Wear of the Cylinder-piston Group

The methodology and results of the experimental studies of crankcase gas consumption in diesel engines with varying degrees of wear of the cylinder-piston group (CPG) are presented. It is shown that the rotation speed has a significant influence on the crankcase gas consumption and the load has an insignificant influence on it. It is recommended to use the idle mode at the nominal or maximum rotation speed as a diagnostic test mode to assess the technical condition of the CPG.