Rapid Starting Research Articles

Prediction and decision of free-piston linear generator on starting process for multi-fuel adaptability

Free-piston linear generators, due to their variable compression ratio, are considered to possess excellent multi-fuel adaptability. Further, fuel-flexible is a weighty research topic for addressing energy source limitations, meeting powertrain generalization requirements, and achieving energy savings and emission reductions. The initial concern to solve is the rapid starting of various fuels within the same free-piston linear generator. This study aims to introduce a mechanical resonance starting performance prediction model based on an artificial neural network and provides a control decision method based on single-objective optimization with soft constraints to achieve flexible starting of a variety of fuels. This paper also assessed the starting performance using the free-piston linear generator prototype and conducted a comprehensive parameterized analysis to investigate the influence of parameters and control variables on starting performance. Using the starting decision method proposed, the control variable values for ethanol starting were derived on the prototype, resulting in driving current at 3.5A, intake air mass flow at 95 standard liters per minute, and intake air temperature at 335 K. This decision value effectively met the predefined requirements, successfully igniting and starting the prototype with ethanol. This outcome serves as a robust validation of the fuel-flexible capabilities within free-piston linear generator systems.

Hybrid power management and control of fuel cells‐battery energy storage system in hybrid electric vehicle under three different modes

AbstractIn most situations, fuel cells (FCs) are insufficient to supply power demands in hybrid electric vehicles (HEVs), thus battery storage systems (BSSs) are used to make the system more efficient like as rapid starting, high power density, and enhanced dynamic set response. How the power sources are regulated and distributed determines the accomplishment efficiency of the driving forces in such a configuration. The most critical aspect should be how to guarantee torque stability of the traction motor which is in our case a permanent magnet synchronous motor (PMSM) while attaining quick reaction. This study discusses a hybrid battery‐FCs energy storage and management system for a hybrid electric vehicle (HEV), as well as an integrated PMSM's passivity‐based control (PBC) technique to enable power integration and increase the hybrid electric vehicle (HEV)'s operating speed. The present paper is separated into two sections. First, a power management control (PMC) technology is used to manage the FCs‐battery system to guarantee that the HEV gets continuous power from the hybrid energy resources, where a fuzzy logic controller is used as an artificial intelligence system for the FCs converter to maximize the power produced. The second is dedicated to the new proposed PBC control of the EV's PMSM to rectify non‐linearities, external disturbances, and parametric fluctuations. The standard proportional‐integral (PI) control and sliding mode control (SMC) are built for comparison with the proposed PBC dedicated to the PMSM in order to properly assess the efficacy of the proposed control strategy. The simulation results obtained using MATALB/Simulink show that the proposed PBC technique and hybrid battery‐ proton‐exchange membrane PEMFCs energy management enables high power integration and increase the EV's operational speed.

Epidemiological Aspects and Seasonal Variation of Meningitis in Egyptian Patients: a Single-Center Study at Abbassia Fever Hospital from 2006 to May 2017

Abstract Background As a result of dangerous complications caused by Meningitis, early recognition, and rapid starting of therapy is very important. Objectives To have an epidemiological profile of patients admitted with meningitis to Abbassia Fever Hospital from year 2006 to May 2017. Patients and methods Meningitis Have a seasonal variations. And this study was done to achieve an epidemiological profile of patients admitted with meningitis to Abbassia Fever Hospital from January 2006 to May 2017. Our study was conducted as retrospective descriptive study at Abbassia Fever Hospital from January 2006 to May 2017. on all of patients admitted to Abbassia Fever Hospital by using data Extraction Sheet. Results Meningitis was more common in Adult age group 60.8%. Meningitis was more common in males 64.4%. More common in Cairo 60.1%. in Cairo it is more common in Nasr city 8.8%. Seasonal variation of meningitis cases was demonstrated in this study with the highest incidence in winter and Spring. The most common symptom of meningitic patients were fever 89.2% followed by convulsions 12.1%, vomiting 10.% and then Headache 7.8% The most common sign in meningitic patients were neck rigidity in 66%, Kernig’s sign in 60%, and Brudizinski’s sign in 40% of patients. Patient of meningitis had convulsions 18.6% and DCL 30.4%, the convulsion and DCL are related to ICU admission. 30.1% of patients of meningitis admitted to ICU. Conclusion Meningitis is more common in males, more common in Cairo.in Cairo it is more common in Nasr city. Meningitis has a seasonal variation commonly, in winter and Spring.

Multi-dimensional optimization of small wind turbine blades

This paper describes a computer method to allow the design of small wind turbine blades for the multiple objectives of rapid starting, efficient power extraction, low noise, and minimal mass. For the sake of brevity, only the first two and the last objectives are considered in this paper. The optimization aimed to study a range of blade materials, from traditional fibreglass through sustainable alternatives to rapid prototyping plastic. Because starting performance depends on blade inertia, there is a complex interaction between the material properties and the aerodynamics. Example blades of 1.1 m length were designed to match a permanent magnet generator with a rated power of 750 W at 550 rpm. The materials considered were (a) traditional E-glass and polyester resin; (b) flax and polyester resin; (c) a typical rapid prototyping plastic, ABS-M30; and (d) timber. Except for (d), hollow blades were used to reduce the rotor inertia to help minimize starting time. Two airfoils are considered: the 10% thick SG6043 which has excellent lift:drag performance at low Reynolds number and the SD7062 whose extra thickness (14%) has some structural advantages, particularly for the weaker material (c). All blade materials gave feasible designs with material (d) the only one that required a blade shell thickness greater than the specified minimum value of 1% of the blade chord. Generally, the blade chord and twist increased as starting was given greater importance. In all cases, the associated increase in blade inertia was outweighed by the larger aerodynamic torque. Materials (a), (b), and (d) were better suited to the SG6043 airfoil whereas ABS-M30 benefitted from the thicker SD7062 section.

Four flippers or two? Tetrapodal swimming with an aquatic robot

To understand how to modulate the behavior of underwater swimmers propelled by multiple appendages, we conducted surge maneuver experiments on our biologically-inspired robot, Madeleine. Robot Madeleine is a self-contained, self-propelled underwater vehicle with onboard processor, sensors and power supply. Madeleine's four flippers, oscillating in pitch, can be independently controlled, allowing us to test the impact of flipper phase on performance. We tested eight gaits, four four-flippered and four two-flippered. Gaits were selected to vary the phase, at either 0 or π rad, between flippers on one side, producing a fore–aft interaction, or flippers on opposite sides, producing a port–starboard interaction. During rapid starting, top-speed cruising, and powered stopping, the power draw, linear acceleration and position of Madeleine were measured. Four-flippered gaits produced higher peak start accelerations than two, but did so with added power draw. During cruising, peak speeds did not vary by flipper number, but power consumption was double in four flippers compared to that of two flippers. Cost of transport (J N−1 m−1) was lower for two-flippered gaits and compares favorably with that of aquatic tetrapods. Two four-flippered gaits produce the highest surge scope, a measure of the difference in peak forward and reverse acceleration. Thus four flippers produce superior surge behavior but do so at high cost; two flippers serve well for lost-cost cruising.

AEROELASTICITY OF AN AIRFOIL TEST RIG

This paper describes an aeroelastic model for an airfoil test rig which is based on the mode superposition method for structural systems and linear airfoil theory for describing the unsteady airfoil loading. The model is applied to the case of an airfoil undergoing rapid, small amplitude step-like maneuvers. The motivation for these tests was an interest in measuring airfoil indicial responses, which are defined as the loading response to a step input in angle of attack. Due to the rapid starting and stopping of the airfoil rig, the structure may experience significant aeroelastic deformations. These may arise from inertial as well as aerodynamic effects. The present model may be of general interest as a means for quantifying and correcting aeroelastic effects in tow tank and wind tunnel test facilities.

The Parsons Centenary—a Hundred Years of Steam Turbines

The first practical multi-stage turbine in the form in which we know it today was built by the Hon C. A. Parsons in 1884. After referring briefly to other pioneers of early turbine development, and outlining the essential differences between impulse and reaction turbines, the main part of the lecture is devoted to a historical survey of steam turbines as applied to the generation of electricity in central power stations, over the intervening one hundred years. Progress in many areas of interest is described: these include considerations of blading design, steam conditions, single- and double-reheat, and many mechanical features, as well as condensing and feed heating plant. Specialized applications of turbines for use with nuclear reactors, for district heating, for use with dry cooling systems where water is scarce, and for rapid starting are also described. Where possible, significant milestones in development are identified by year and by builder; progress up to the present day is reported. Some of the problems which sometimes arise with turbine plant in service are briefly mentioned, and the prospects of developments over the next few years, including the possibility of significant increases in steam pressure and temperature, are outlined.

An Elastomeric Energy Storage Device for Automotive Engine Restart

Abstract An elastomeric spring starter using rubber in shear has been designed. Design criteria have been established and used to develop potential compounds for use in the device. Natural rubber proved to be the elastomer of choice primarily because of its excellent fatigue resistance. To reconcile bonding requirements and requirements for low hysteresis, the individual rings were fabricated from two elastomer compounds. Limitations on the thermal stability of the adhesive system were identified which put constraints on the operating conditions for the starter. A prototype starter has been assembled and installed in a vehicle. This prototype starter provides quiet, rapid starting of the test car. Questions of cost effectiveness, reliability, durability or manufacturing feasibility of this device have not been addressed. The starter was built for experimental purposes only and development of such a concept for mass production has not been explored.

Starting Torque Characteristics of Small Aircraft Gas Turbines and APU’s

Starting torque characteristics of small self-sufficient gas turbine engines often present a belated problem to the development engineer, particularly when proceeding into final engine qualification testing over the required range of operational environments. A common procedure is therefore to conservatively over-design the start system with consequent penalties in weight, cost, and size. The various aspects of engine starting are discussed and it is shown that the dominant factor controlling start characteristics at sub-zero ambient temperatures is lubricant viscous shear effects. The magnitude of this effect is such that stored energy start system weights for rapid starting of small aircraft auxiliary power units may weigh as much as the power unit itself. The same auxiliary power units, if used as starters for larger main propulsion gas turbines, are burdened with the incompatibility of torque output dependent upon air density, yet main engine cranking torque is dependent basically upon lubricant viscosity. It is concluded that start system over-design philosophy will tend to persist pending the application of external starting torque directly to the high speed shaft itself with uncoupling of all but necessary viscous parastic shear sources, or until such time as detailed research and development is devoted in applied tribology to further reduce viscous shear effects in high speed turbo-machinery.

Purification and characterization of a putative sigma factor from Chalamydomonas reinhardi.

Two proteins with sigma-like activity have been isolated from the alga, Chlamydomonas reinhardi. One protein, sigma 2, has been partially purified and appears to have a molecular weight of 51,000. The interaction of this protein with a heterologous (Escherichia coli) and homologous (Chlamydomonas, chloroplast rifampicin-sensitive) core RNA-polymerase (RNA nucleotidyltransferase, nucleosidetriphosphate: RNA nucleotidyltransferase, EC 2.7.7.6) was studied. Sigma 2 protein appears to stimulate the formation of open (rapid starting) binary complexes by both of the core enzymes. Stimulation of transcription by sigma 2 on chloroplast DNA was greater when Chlamydomonas core enzyme was used. Moreover, in vitro transcription on a variety of templates using RNA polymerases I and II from Chlamydomonas was not stimulated by this protein.

I.n vitro transcription of adenovirus 2 DNA. I. Characterization of promoters for E. coli RNA polymerase.

E coli RNA polymerase holoenzyme is able to recognize transcription initiation sites on Adenovirus 2 DNA that are functionally indistinguishable from promoters for the enzyme on phage DNAs. The complexes formed between the polymerase and the DNA at these sites can exist in two states-either as I (initiation) complexes, from which rapid RNA chain initiation is not possible, or as RS (rapid starting) "rifampicin resistant" complexes, from which rapid RNA chain initiation can occur. When transcription is limited to that initiated from stable, rifmapicin-resistant pre-initiation complexes, initiation is strictly dependent on the presence of sigma factor; in addition, the frequency of initiation exhibits sigmoidal dependence on the temperature at which pre-initiation complexes are allowed to form, with a transition temperature of 26-28 degrees C. The average half-time for initiation of RNA chains from sites on Ad 2 DNA is shown to be comparable to half-times for initiation of RNA chains from promoters on T7 and lambda DNAs. At saturating levels of enzyme, the half-times are 0.6, 0.9, and 1.6 sec for lambda b2, Ad 2 and T7 DNAs, respectively. The existence of efficient, phage-like promoters for E coli RNA polymerase on Ad 2 DNA suggests to us that such promoters may be closely related functionally and spatially to promoters for mammalian RNA polymerases.

The growth of the pollen tube wall in Oenothera organensis

The growth of the pollen tube wall of Oenothera is effected by the expulsion of fibrillar material from the cytoplasm into the developing wall. This material may also be seen in the cytoplasm, contained in membrane-bound vesicles. It is not clear how the content of the vesicles is discharged, but it appears not to involve the participation of microtubules. The source of the cytoplasmic fibrillar bodies depends upon the stage of development of the pollen tube. The earilest growth is derived from the inclusion into the wall of vesicles containing pre-formed materials present in the grain on pollination. During the next stage of growth the wall is derived from the content of double-membraned inclusions also present in the pollen. The content of the former vesicles is not so similar to the wall as the latter, but intermediates between the 2 types of vesicle may be seen in the cytoplasm, indicating that the former are formed from the latter. Most of the tube wall is derived from the products of dictyosomes in the pollen grain or tube. These dicytosomes are few in number and they must be exceedingly active. This, and the observation that dictyosome vesicles are frequently associated with banked complexes of mitochondria, indicates that some steps in the metabolism of the vesicular content, perhaps phosphorylation, take place distant from the dicytosomes. These different sources of fibrillar material presumably permit the rapid starting of tube growth, without any attendant metabolism. However, it would be impossible to include enough pre-formed wall material in the grain to enable the full growth of the tube, so once started, it seems that the tube then relies on the elaboration of simple reserves for the contruction of its wall. These reserves are likely to be held in the pollen, and may be the large numbers of starch grains characteristic of the pollen cytoplasm.

The mechanism of rapid starting of slender fish.

The mechanism of rapid starting of slender fish.

Paper 13: Recent Developments in the Control of Industrial Gas Turbines

This paper describes the control systems required for the application of gas turbines to fully automatic generating stations, and mechanical drives such as natural gas compressor stations. Gas turbine power plant has definite advantages in that for the power output it lends itself to relatively simple fully automatic operation of the overall plant and rapid starting and loading. The relatively low capital cost and size have resulted in widespread applications of this type of plant. The large gas turbine plant can be divided into two main categories: (1) Aero powered gas turbines. (2) Pure industrial gas turbines. The role of the control system is not only to adapt the gas turbine to the particular application but to ensure the safety and protection of the plant at all times. The control functions include: Those necessary for the particular application, e.g. power turbine speed control. Those necessary for the protection and correct operation of the gas turbine system, e.g. balance of multiple gas generators discharging into power turbine. The peripheral systems, e.g. automatic sequence systems for starting. This paper is based on the author's recent experience in this field.

Logarithmic-diode count-rate and period meter

THE DESIRE to achieve safe automatic start-up of nuclear power reactors — especially where rapid starting of marine or airborne reactors is required — has led to attempts to measure transients in neutron flux at power levels that correspond to 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−10</sup> , or less, of full operating power. At these levels, one uses instruments such as counters and count-rate meters, that operate on individual neutron detections. Logarithmic count-rate meters are frequently used for convenience in monitoring wide ranges of neutron flux. Furthermore, the variable most commonly used for control during reactor start-up is the time derivative of the logarithm of the neutron flux, which is by definition proportional to the reciprocal of the period.

Hot-cathode thyratrons: practical studies of characteristics

The paper surveys the main features which determine the characteristics and life of thyratrons in the light of direct experiment and of field experience. These include electron emission from the cathode, ionization and current build-up, grid control, the current-carrying capacity of the valve, the decay of ionization at the end of conduction, and the provision of suitable operating conditions.Emphasis is laid on factors which, while not immediately affecting electrical performance, may determine valve life; one example is positive-ion bombardment, which may cause damage to the cathode.The control characteristics of different types of grid are discussed; particular reference is made to the pentode design, a recent development enabling heavy currents to be controlled from high-impedance grid circuits.The arc voltage drop varies considerably with filling pressure and with current value, abrupt changes being associated with modifications in the form of the discharge. If the current-carrying capacity of the arc path is exceeded, the arc, if it cannot transfer to an alternative path, may suddenly go out, giving rise to generally undesirable high-voltage surges.A method of studying de-ionization time is described, and results are given showing this time as a function of the gas and its pressure. The characteristics of various gas and vapour fillings are discussed. A non-uniform pressure distribution in mercury-vapour valves assists rapid starting.

Gas-Turbine Propulsion in a Naval Vessel

Messrs. Metropolitan-Vickers Electrical Co., Ltd., Trafford Park, Manchester, have installed gas-turbine propulsion equipment in the experimental naval craft, M.G.B. 2009, the trials of which will take place in the near future. The Company claims that this is the first naval vessel ever to be propelled by a gas-turbine. The characteristics of the simple-cycle gas-turbine include low overall specific weight and size with rapid starting, and these qualities make it very suitable for light vessels where high speeds may be required for limited periods and at short notice. In M.G.B. 2009, normal cruising and astern power is provided by two 1,250 b.h.p. 2,400 r.p.m. Packard internal combustion reciprocating engines, each engine driving its own propeller through a reduction gear. Maximum ahead power is obtained by bringing into operation a completely independent Metropolitan-Vickers gas-turbine of 2,500 b.h.p., which drives a third propeller through speed-reduction gearing to supplement the power of the reciprocating engines.