The restricted concave kite five-body problem is a problem in which four positive masses, called the primaries, rotate in the concave kite configuration with a mass at the center of the triangle ...formed by three of the primaries. The fifth body has negligible mass and does not influence the motion of the four primaries. It is assumed that the fifth mass is in the same plane of the primaries and that the masses of the primaries are m1, m2, m3, and m4, respectively. Three different types of concave kite configurations are considered based on the masses of the primaries. In case I, one pair of primaries has equal masses; in case II, two pairs of primaries have equal masses; in case III, three of the primaries have equal masses. For all three cases, the regions of central configuration are obtained using both analytical and numerical techniques. The existence and uniqueness of equilibrium positions of the infinitesimal mass are investigated in the gravitational field of the four primaries. It is numerically confirmed that none of the equilibrium points are linearly stable. The Jacobian constant C is used to investigate the regions of possible motion of the infinitesimal mass.
We explore the central configuration of the rhomboidal restricted six-body problem in Newtonian gravity, which has four primaries mi (where i=1,…4) at the vertices of the rhombus a,0, −a,0, 0,b, and ...0,−b, respectively, and a fifth mass m0 is at the point of intersection of the diagonals of the rhombus, which is placed at the center of the coordinate system (i.e., at the origin 0,0). The primaries at the rhombus’s opposite vertices are assumed to be equal, that is, m1=m2=m and m3=m4=m˜. After writing equations of motion, we express m0,m, and m˜ in terms of mass parameters a and b. Finally, we find the bounds on a and b for positive masses. In the second part of this article, we investigate the motion and different features of a test particle (sixth body m5) with infinitesimal mass that moves under the gravitational effect of the five primaries in the rhomboidal configuration. All four cases have 16, 12, 20, and 12 equilibrium points, with case-I, case-II, and case-III having stable equilibrium points. A significant shift in the position and the number of equilibrium points was found in four cases with the variations of mass parameters a and b. The regions for the possible motion of test particles have been discovered. It has also been observed that as the Jacobian constant C increases, the permissible region of motion expands. We also have numerically verified the linear stability analysis for different cases, which shows the presence of stable equilibrium points.
With the world׳s predicted wave-power capacity of 1–10TW many projects are being implemented around the world and have brought in many useful insights and innovations during their implementation. ...This paper discusses the major projects, the world over, for the generation of electrical power from wave energy. The literature for these projects is reviewed extensively to describe the waves as potential sources of electrical energy: different challenges that these projects faced and how these challenges were tackled are also discussed. Methods for the wave-energy conversions for each of these projects will also be critically reviewed and the economic and environmental aspects are also explored. The paper aims to summarize the technologies, challenges and technical considerations for harnessing wave energy to set a path for future development. The experiences of the previous projects and the lessons learnt from them can be very helpful for the future development of similar projects: in this context the Perth Wave Energy Project is presented and discussed in detail.
We discuss the restricted rhomboidal six-body problem (RR6BP), which has four positive masses at the vertices of the rhombus, and the fifth mass is at the intersection of the two diagonals. These ...masses always move in rhomboidal CC with diagonals 2a and 2b. The sixth body, having a very small mass, does not influence the motion of the five masses, also called primaries. The masses of the primaries are m1=m2=m0=m and m3=m4=m˜. The masses m and m˜ are written as functions of parameters a and b such that they always form a rhomboidal central configuration. The evolution of zero velocity curves is discussed for fixed values of positive masses. Using the first integral of motion, we derive the region of possible motion of test particle m5 and identify the value of Jacobian constant C for different energy intervals at which these regions become disconnected. Using semianalytical techniques, we show the existence and uniqueness of equilibrium solutions on the axes and off the axes. We show that, for b∈1/3,1.1394282249562009, there always exist 12 equilibrium points. We also show that all 12 equilibrium points are unstable.
The model predictive control (MPC) technique for a solar-based series-resonant inverter conventionally used in domestic heating is explored. The photovoltaic energy system (PVES) converts the solar ...energy into electrical energy where DC voltages of different cells are linked at a common bus. A Cuk-converter is used to interface the PVES with the DC load bus and the heating inverter. These heating inverters are replacing gas cookers in restaurants, guest rooms, and domestic- and commercial-kitchens for cooking of various foods. A number of control algorithms have been employed to control the power of the heating inverter but they have certain limitations; especially they do not predict the future response of the circuit. The MPC, an advanced control approach, has the potential to estimate the future behaviour of the model in a predictive manner. Hence, to control the power of the resonant inverter connected with a 3.36 kW heating load, MPC is applied. The simulation results verify the validity of the power control of a solar-based series-resonant inverter using the MPC algorithm.
In the present study, the effect of concentration of titanium carbide (TiC) particles on the structural, mechanical, and electrochemical properties of Ni-P composite coatings was investigated. ...Various amounts of TiC particles (0, 0.5, 1.0, 1.5, and 2.0 g L
) were co-electrodeposited in the Ni-P matrix under optimized conditions and then characterized by employing various techniques. The structural analysis of prepared coatings indicates uniform, compact, and nodular structured coatings without any noticeable defects. Vickers microhardness and nanoindentation results demonstrate the increase in the hardness with an increasing amount of TiC particles attaining its terminal value (593HV
) at the concentration of 1.5 g L
. Further increase in the concentration of TiC particles results in a decrease in hardness, which can be ascribed to their accumulation in the Ni-P matrix. The electrochemical results indicate the improvement in corrosion protection efficiency of coatings with an increasing amount of TiC particles reaching to ~ 92% at 2.0 g L
, which can be ascribed to a reduction in the active area of the Ni-P matrix by the presence of inactive ceramic particles. The favorable structural, mechanical, and corrosion protection characteristics of Ni-P-TiC composite coatings suggest their potential applications in many industrial applications.
The design analysis of a multi-input converter using an intelligent controller based on fuzzy logic control algorithm is encompassed. The use of dedicated dc–dc converters is going through a ...transitory phase in smart-grid applications. Different characteristics of inputs can be combined to give desired output operation by using a multi-input converter which is more or less the combination of individual converters sharing a common load thus simultaneously transferring power to the load. The converter with the help of an intelligent algorithm will ensure the buffering time for each input thus multiplexing between various inputs according to the set demand and fluctuating conditions on the input side. Such a converter will behave as a power electronic interface between the utility, user and the renewable energy sources. A three-input cuk converter has been designed for interfacing wind energy sources with the dc load bus and the main grid. Sending power to the main grid incorporates the power quality enhancement features which will be accommodated using the bi-directional inverter connected with the grid to perform the active filtration. Moreover, three fuzzy logic controllers will set the output currents corresponding to each input current by changing their reference voltages according to the power demand.
Background: According to the United Nations, about one in five Indians will be 60 years or older by year 2050. Following this demographic shift, an increase in the proportion of cognitive disorders ...is expected. This study aims to identify those who have cognitive impairment among the rural elderly and study the factors associated.
Methodology: The cross-sectional study was done on patients attending rural health and training centre of a tertiary care medical college and hospital in Chennai. One hundred seventy-eight participants above 60 years of age were screened with the Mini-CogTM tool. Those who scored less than 4 on the Mini-Cog scale were referred for cognitive evaluation by a clinical psychologist.
Results: The overall prevalence of individuals positive for cognitive impairment was 41.6%. On bivariate analysis, individuals older than 65 years of age, those who were leading a retired life, not living with spouse, current alcoholics and smokers were associated with impaired cognition. Multivariate logistic regression analysis revealed participants who were retired and not living with spouse were independently associated with cognitive impairment.
Conclusion: A high proportion of participants screened positive for cognitive impairment. Integrating cognitive health with primary care can help in giving attention and support for the ageing population.
•Less than 100nm polysilicon nanogap based simple electrode sensor for glucose detection was fabricated.•The biosensor produced discriminatory signals for different concentration of dextrose sample ...and salivary sample.•We have successfully measured glucose quantitatively at detection range from 5μM to 50mM with sensitivity detection of 42.08μAmM−1cm−2.•The biosensor response time was achieved in 3s and the detection limit was calculated to be 0.6μM.
A highly sensitive and non-invasive label-free biosensor was demonstrated for glucose detection using (3-aminopropyl)triethoxysilane (APTES) and glucose oxidase (GOx) surface modified polysilicon nanogap (PSNG) lab-on-chip. Fabricated gap size below 100nm nanogap (NG) was used to discriminate the detection of the prepared dextrose monohydrate (DEX) which used as reference. The results were compared with salivary glucose (SAL) samples and an on spot blood glucometer. A simple immobilization step of APTES and GOx was demonstrated and the result shows an excellent catalytic activity toward the oxidation of glucose with a current sensitivity of 42.08μAmM−1cm−2 (or NG conductance sensitivity of 165.3nScm−1). It was found that the working capability of this enzyme based biosensor was extremely wide linear ranging from 5μM to 50mM, and the limit of detection (LOD) can be achieved down to 0.6μM. Moreover, the amperometric response has affectively distinguished, the sensor response time of 3s is achieved. The reproducibility and stability of the enzymatic activity of biosensor were successfully distinguished for glucose sensing. AC dielectric and impedance spectroscopy measurement also shows insignificant effect of polarization which is due to the accumulation of ions (double layers) on the surface of PSNG electrodes. Therefore, this glucose biosensor could be an attractive candidate for commercialization as a point-of-care clinical diagnostic tool.
Incisional cerebrospinal fluid (iCSF) leakage is a serious complication after intradural cranial surgery.
To determine the incidence and risk factors of iCSF leakage after craniotomy. Secondarily, ...the complications after iCSF leakage and the success rate of iCSF leakage treatment was studied.
All patients who underwent an intradural cranial surgery from 2017 to 2018 at 5 neurosurgical centers were retrospectively included. Data were retrieved from medical records with 2 months of follow-up. First, univariate regression analyses were performed. Subsequently, identified risk factors were evaluated in a multivariate regression analysis.
In total 2310 consecutive patients were included. Total iCSF leakage rate was 7.1% (n = 165). Younger age, male, higher body mass index, smoking, infratentorial surgery, and use of a dural substitute were associated with increased iCSF leakage risk, and use of a sealant reduced that risk. The odds for developing a wound infection and/or meningitis were 15 times higher in patients with iCSF leakage compared with patients without leakage. Initial conservative iCSF leakage treatment failed in 48% of patients. In 80% of cases, external cerebrospinal fluid drainage ceased the iCSF leakage. A total of 32% of patients with iCSF leakage required wound revision surgery.
iCSF leakage risk increases by younger age, higher body mass index, smoking, infratentorial craniotomy, and dural substitute use, whereas sealant use reduced the risk for iCSF leakage. The leak increases the risk of postoperative infections. When iCSF leakage occurs, immediate external cerebrospinal fluid drainage or wound revision should be considered.
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