This paper presents an analytical formulation of the force and torque generation mechanism of a bearingless split teeth flux reversal motor. This bearingless motor generates torque and force using harmonic flux densities created by the modulation of flux densities from various sources by the rotor. This motor design features a force production independent of the rotor angular orientation which significantly simplifies the suspension control. The analytical formulation explains this desirable force behavior and the torque generation using harmonic analysis of the airgap flux densities. The formulation is verified using finite element simulations and experimental results which are performed using a fabricated motor capable of operating at up to 3000 rpm with up to 100 mNm torque and 50 N radial force capability.

In bearingless slice motors, the passive axial and tilt stiffnesses acting on the rotor are important for constraining rotor motions. This paper presents a novel approach to increasing these stiffnesses by using axial castellation. In this approach, the stator and rotor surfaces facing the working airgap are formed with teeth (castellation) in the axial direction. This tooth structure enhances magnetic energy variation with respect to axial and tilt motions, and consequently raises the stiffness in these degrees of freedom. The paper also shows that a further increase in these stiffnesses can be achieved by including small radially magnetized inter-tooth permanent magnets located in the slots between the teeth. To support this new design, a reluctance-based circuit model is created to elucidate the mechanisms contributing to enhanced passive stiffness. Finite element simulations are then used for the detailed motor design, and to optimized the passive stiffness via parametric studies. A representative design has been constructed to allow experimental measurement of the axial and tilt stiffnesses. These experimental results demonstrate a significant improvement in the passive stiffness for bearingless motors with the castellation, and with the use of inter-tooth magnets. This paper also discusses alternate motor modifications to enhance the passive stiffnesses.

This paper describes and implements a semi analytical modelling approach for an interior permanent magnet bearinglesss slice motor. The method is developed to estimate the cogging torque, motor torque and suspension force as a first optimization step for the design. All these parameters are important for the bearingless motor performance. Major nonlinearities associated with an IPM motor that affect these parameters are considered in modelling using different methods. A reluctance based circuit model is used to obtain the rotor and stator flux individually. This model contains the basic geometry information and the saturation of rotor bridges. The effect of stator slots are included by redistributing the airgap flux. When both stator induced and rotor induced flux are obtained in the airgap, the net flux is used to calculate the cogging and motor torque using energy method and force using stress tensor. The results are shown and discussed in the paper and the model is able to estimate the behavior closely. Despite some magnitude offset, the model can predict cogging torque trends and airgap harmonics, making it a useful design optimization tool.

This article describes a position sensor with six degrees of freedom (DoF) measurement capability. This sensor is designed for the position sensing of the rotor in a bearingless slice motor to enable active control. The sensor is designed to fit entirely under the rotor and operates by accessing the rotor bottom surface only, enabling packaging of the pump on the top of the rotor. The sensor has two parts; both operate using eddy currents. One of these parts measures the two radial DoF of the rotor. The other part measures the axial, angular rotation and tip/tilt DoF. The sensor utilizes a conductive target fixed to the underside of the rotor. Motion of this target varies the magnetic fields, which can then be measured by the sensor as variation in either induced voltage or inductance value. The design and fabrication of the sensor along with the signal processing methods are presented in detail. The radial position measurements are the most critical for active levitation due to the small working gaps in these DoF, hence a resolution of $<1.2\ \mu \rm {m}$ and bandwidth of 1 kHz is achieved. This article also describes the closed-loop behavior of a bearingless motor using this sensor.

This paper describes a novel bearingless split tooth flux reversal motor with integrated centrifugal blood pump. This motor has a magnet-free rotor, and is capable of operating at up to 3000 rpm with up to 100 mNm torque. The motor also has 50 N radial force capability for centering the rotor. The motor rotor is 50 mm diameter, housed in a 170mm wide stator. The motor has a novel magnetic configuration wherein the force generation is independent of the rotor angle. This allows simple radial force generation using stator-fixed currents. The motor torque is generated using commutated two-phase currents. Finite element simulations are used to optimize the design in order to achieve sufficient radial force and motor torque, while minimizing cogging torque. The design also achieves an axial passive magnetic stiffness of 5.4 N/mm, which is the constraint on axial motions of the rotor. This paper includes mechanical design and fabrication details, as well as experimental closed loop levitation and speed control performance. With an integrated impeller, the rotor and the centrifugal pump are tested by pumping fluid in a closed circuit to obtain experimental pressure-flow curves with impeller-limited performance.

Radon in water has exposure to the population through ingestion and inhalation. In the present paper, radon levels in fifty-eight samples from different underground water sources (borewell, handpump, tap water, which are used for drinking purposes) and surface water sources (pond, canal) located in district Gurugram, Southern Haryana, India, measured. SMART RnDuo (having ZnS:Ag detector) based on alpha scintillometry technique was used for this purpose. The dissolved radon in water ranged from 1.1 to 15.2 BqL(-1) with a mean value of 6.8BqL(-1). Radon in drinking water samples was about six times higher than the surface water samples in district Gurugram. A trend of increase in radon level with an increase in source depth was observed. Annual effective doses due to ingestion (AED(ing)) and inhalation (AED(inh)) were calculated for different age groups. Total annual effective doses due to AED(ing) and AED(inh) are varied from 8.6 to 118.7 mu Sv y(-1) with a mean value of 53.1 mu Sv y(-1) for infants, 4.9 to 67.9 mu Sv y(-1) with a mean value of 30.3 mu Sv y(-1) for children, and 5.6 to 77.1 mu Sv y(-1) with a mean value of 34.5 mu Sv y(-1) for adults. Radon in water samples was found to be less than the guideline value of 100 BqL(-1) recommended by the World Health Organization, indicating that water sources are suitable for use by the public and have no radiological hazards.

The creation of novel materials has grown tremendously, but the main issue is that they are exceedingly challenging to manufacture. So, it is essential to implement certain new machining techniques. Due to its capacity to create detailed, complex forms and to work with hard materials, (EDM) is a nontraditional and widely used machining technique to make machine dies, machine punches, and various press tools. Copper, brass, and graphite were employed as the three distinct electrode materials in the experiment along with dielectric fluid.L9 orthogonal array has been selected using the taguchi technique, and three levels are taken for each of the variables. The set of tests that were planned in an orthogonal array have been carried out. Experimental results were examined analytically and visuallyThe optimal values of MRR were calculated. Experimental findings revealed that, brass electrodes with greater surface polish had lower current values (18 A) and longer pulse-on periods (65 S) than copper electrodes with the highest MRR (30 A) and pulse-on values (50 S).

In light of its direct effects on human health and well-being, abnormally high uranium (U) prevalence in groundwater is a neoteric topic of concern worldwide. Because it is readily available in rural and urban areas of India and other parts of the world, groundwater is the preferred option for drinking. India has a large agricultural sector, and groundwater provides 50%–80% of the country's irrigation demands and almost 90% of its rural and 50% of its urban water needs. The uranium concentration in groundwater was found to vary between 0 mg/L and 1443 mg/L in different regions of India, including Punjab, Haryana, Rajasthan, Madhya Pradesh, and Karnataka, and up to 1400 mg/L in other nations, including the United States, Canada, Finland, Mongolia, Nigeria, South Korea, Pakistan, Burundi, China, and Afghanistan. The addition of uranium to groundwater is caused by a number of natural and anthropogenic causes, including mining, nuclear operations, unpredictable fertilizer usage, and overexploitation of groundwater resources. Geology, hydrogeochemistry, and environmental conditions are natural components that contribute to this. Since groundwater contributes 85% of the uranium that humans consume, compared to food's 15%, it is thought to be the main source. Uranium has a two-pronged effect on living things; as a radioactive element, it may induce radiotoxicity and chemotoxic effects as a heavy metal. Consuming water polluted with uranium can have a negative impact on the kidneys, bones, and lungs, among other target organs. Renal failure, cellular dysfunction, impaired bone formation, and DNA mutation are all possible effects. However, due to its nature as a heavy metal, the toxic effects it are more severe than its radiotoxicity. Several methods for effectively removing uranium from groundwater include bioremediation, nanotechnology-assisted remediation, adsorption, filtration, and others. This chapter thoroughly analyses uranium contamination in groundwater in rural and urban areas of India, including information on its likely origins, potential effects on human health, and treatment and mitigation options.

Pristine ZnO and Sm-doped ZnO nanoparticles were synthesized using a wet chemical co-precipitation technique. The morphological and structural characteristics of pristine and Sm-doped ZnO were studied by field-emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD) techniques. Increases in lattice parameters, interplanar spacing, and volume was observed from the XRD patterns compared to its JCPDS card. Crystallite size, dislocation density, deformation stress, lattice strain, and energy density for both pristine and Sm-ZnO nanoparticles were calculated using Scherrer and Williamson–Hall (W–H) methods. An energy bandgap reduction was observed in the Sm-doped ZnO (Eg 2.7 eV), which played a crucial role in explaining the increased leakage currents in Sm-ZnO. The Sm-doped ZnO nanoparticles exhibited a remnant polarization (Pr 0.163 µC/cm2) and a coercive field (Ec 25.33 kV/cm). Current–voltage (I–V) characteristics show maximum current generated on applying varying voltages (Vmax = 40 V, Imax = 600 μA). Frequency- and temperature-dependent dielectric studies were conducted to examine the change in the values of the dielectric constant and dielectric loss with the variation in frequency and temperature. The Sm-doped ZnO-based nanogenerator generated an output voltage 400 mV at tapping force of 0.02 kgf, which makes it a prominent candidate for self-powered devices.

In the present study, 366 locations were selected from the Faridabad district of Haryana, India, for seasonal gamma radiation measurements in indoor/outdoor environments. It was measured by a radiation monitor PM 1405 (Polimaster instrument/Republic of Belarus). The measured gamma was statistically analysed using the Wilcoxon signed-ranks test, Shapiro–Wilk test, Mann–Whitney test, and ANOVA test. The significance value of the outdoor gamma dose rate in winter (OGDRW) is found to be less than the significance level (0.05), indicating that the geology has a significant impact on OGDRW. The estimated annual effective dose was related to the values stated by UNSCEAR and ICRP.

The paper deals with the ovarian development of Macrobrachium dayanum. The development of the oocyte into mature ova has been studied under two principal categories viz., pre-vitellogenic and vitellogenic phase. Other than oocytes, oogonia have also been seen in the ovaries during different months of the year. It has been observed that the ovaries of Macrobrachium dayanum possess maximum percentage of oogonia during the months of December to January and June to July which indicate that they are passing through immature stage. It was further observed that during the month of April and October to November ovaries were filled with primary, secondary and tertiary vitellogenic oocytes.

Forty soil samples from district Palwal of Southern Haryana, India were collected to estimates the radon/thoron exhalation rate using scintillation detector-based SMART RnDuo out of which twenty samples were tested to estimate the activity of Ra-226, Th-232 and K-40 using high purity germanium (HPGe) gamma-ray spectrometry. The radon mass exhalation rate (mBqkg(-1)h(-1)) was observed as {range (mean)} {16 +/- 1-48 +/- 3 (28 +/- 8)} and thoron surface exhalation rate (Bqm(-2)h(-1)) was observed as {1800 +/- 198-6331 +/- 205 (3850 +/- 850)}. Activities of radium (Ra-226), thorium (Th-232) and potassium (K-40) were {range (mean)} observed as {28.4-48.4 (40.0 +/- 1.4)}, {49.7-75.0 (62.7 +/- 1.6)} and {432-698 (522.9 +/- 17.6)}, respectively. It is observed that the radium in 75% samples while thorium and potassium in all samples were found to higher than the world's average values of 35, 30 and 400 Bqkg-(1), respectively, as reported by UNSCEAR. Average of radon mass exhalation and thoron surface exhalation rates exceeded the world's mean value 57 mBq kg(-1) h(-1) and 3600 Bq m(-2) h(-1), respectively. Health hazard index is well below the unity (< 1), which indicates that there are no gamma radiation hazards associated with samples collected from the study region.

Seasonal monitoring of 222 Rn and 220 Rn using Pin-holes dosimeter and their progenies by deposition-based sensors was conducted in 150 dwellings of district Gurugram of State Haryana, India. Annual indoor 222 Rn, 220 Rn, radon progeny, and thoron progeny were found in the range 8.1–76.2 Bqm −3 with a mean value of 29.2 ± 1.1 Bqm −3 , 10.2–86.2 Bqm −3 with a mean value of 35.1 ± 1.4 Bqm −3 , 1.2–32.5 Bqm −3 with a mean value of 9.1 ± 0.2 Bqm −3 , and 0.2–14.1 Bqm −3 with a mean value of 1.2 ± 0.1 Bqm −3 , respectively. Highest level was observed in winter season and in moderns dwellings. Measured radionuclides concentration was used to calculate the total annual effective dose.

Electrical properties of matter has a very significant role in characterization of a particular material to utilize it for device applications. One-dimensional nanostructures play an important role as interconnects in nanoscale based electronic devices. Hence, the flow of electric current is a very significant parameter to control the quality of electronic device. The electrical conductivity of nanomaterials is found to vary with diameter of 1D nanostructures. However, keeping the diameter of 1D nanostructures constant, and exposing them to radiations can also cause reduction in their electrical conductivity. In present work, we analyzed the consequence of gamma rays induced variation in current voltage characteristics and hence the electrical conductivity of 1D silver and zinc nanostructures. We synthesized the 1D silver and zinc nanostructures via TEMs and exposed them to gamma radioactive Cobalt-60 source. In the post exposure cases, I-V characteristics (IVC) are found to be severely affected that indicates the dampening of electronic flow across nano-needles. And around 2 Volts of applied potential difference, electronic flow across 1D nanostructures approaches to zero, however, a little variation in the potential is observed in different cases of irradiation with no specific pattern.

This paper presents a radial position sensor for the bearingless slice motors with magnet free rotor. The sensor operates on the principle of eddy currents by interacting with a conductive target attached to the rotor. The conductive target varies the flux linkage and hence induced EMF in the sensor coils which is used to obtain the position measurements. The sensor is capable of measuring the radial degrees of freedom by accessing the rotor bottom surface only. The bottom surface has higher sensitivity for axial and tilt measurement and a lower sensitivity for radial measurement. The radial sensitivity depends on the axial gap between the rotor and target. The variation in airgap varies the flux linkages in the measurement coils and couples the tilt and axial motion to the radial measurement. The coupling of radial measurement to the tilt is overcome by sensor and target design [6]. The axial coupling is solved by adding another coil in the sensor to measure axial gap between sensor and target and the axial measurement is used to actively decouple the radial measurement. The construction and operation of the sensor is explained and the axial decoupling is verified using the simulation and experimental results.

Natural radioactivity is the term used to describe radioactivity that persists in the soil, rocks, and water due to fundamental radionuclides such as uranium, thorium, potassium, etc. As a result, radiation affects everyone on the planet. Researchers worldwide find this topic particularly interesting due to the hazardous effects of radionuclides on human health. A systematic survey employing trustworthy methodological approaches is necessary to objectively assess these radionuclides in the environment. In the present paper, ZnS:Ag scintillator-based SMART RnDuo (AQTEK System, India) is used to measure exhalation rates of isotopes 222Rn and 220Rn (radon and thoron) of soil samples. Forty soil samples were studied. For the study of 222Rn, monitoring of the mass exhalation (Rm) was conducted. In the case of 220Rn, monitoring of surface exhalation (Rs) was studied. The radon mass exhalation rate is found in the range of 14±1 to 55±5 mBqkg−1h−1 with an average of 34±10 mBqkg−1h−1 and thoron surface exhalation rate in the range of 2200±215 to 7560±420 Bqm−2h−1 with an average of 4280±960 Bqm−2h−1. Thus, elevated thoron level is observed in most of the samples. Results are compared with the world’s average values.

High inductance actuators are found in many mechatronics systems and inverter requires higher voltage DC bus to drive these actuators with variable frequency and current magnitudes. Since the load is dominantly reactive, only a small current is required from the DC source to feed the active power of the load. In some applications, these actuators require AC and/or DC currents for the operation. In this paper, a control algorithm is proposed for a cascaded multilevel inverter with only one DC source to drive high inductance loads with AC and/or DC currents. It also offers the advantages of the multilevel inverter like multilevel voltage and low voltage rating switches. Multiple inverters can be added in series without DC source to get the desired voltage rating, but continuous active power rating is defined by the one inverter with DC source. The control system is developed to achieve the commanded AC and/or DC load current, to regulate the DC bus voltage of the inverter without DC source and manage the power sharing between the inverters during steady and transient operations. The experimental results are obtained to verify the inverter performance under various operational scenarios.

A study was conducted for the measurement of outdoor gamma dose rate (GDR) using a radiation monitor, based on Geiger-Muller technique, in Karnal, Kaithal, and Kurukshetra districts of Haryana at 214 locations during post and premonsoon season. The γ-dose rate was found to be in the range of 70 ± 4–267 ± 13 nSv/h. The data was statistical analysed and distribution was interpolated using ArcGIS software. The annual effective dose (AED) due to outdoor γ-radiation in Karnal, Kaithal, and Kurukshetra districts was computed to be in the range of 0.086 ± 0.004–0.327 ± 0.016 mSv/y. The value of excess lifetime cancer risk (ELCR) was found to be in the range of 0.322 × 10 −3 –1.228 × 10 −3 .