Search

Economic and social development of nations across the globe is demanding enormous need for energy and power resources. Energy production using safe and renewable sources can aid in mitigating the release of greenhouse gases and avoiding the devastating climate changes. In the present case, a linear type magnetostrictive transducer device is designed by employing Terfenol-D magnetostrictive rods for renewable energy harvesting application. A linear device was designed with two Terfenol-D rods, three permanent magnets (neodymium magnets), springs, and primary and secondary coils. Terfenol-D rod crystallizes in cubic Laves phase and exhibits the saturation magnetostriction value of 1242 × 10−6 at the field of 2.5 kOe. An equivalent circuit is constructed for the induced magnetic flux in the designed transducer device. Frequency and wave form dependent output voltage is examined in the designed energy harvesting device. A square wave at the applied frequency of 2200 Hz (100 mA current) produces a maximum output voltage of 4.91 V. Sine and triangle waves produce 3.38 and 2.82 V, respectively, at 1700 and 1600 Hz. The induced voltage is sufficient to ignite the light emitting diode. A linear type magnetostrictive transducer can be employed as a potential renewable energy source for real-time application with moderate output voltage. [ABSTRACT FROM AUTHOR]

This paper presents the different beam geometries for vibration-excited piezoelectric energy harvesters. The performance of various beam geometries are analysed by comparing frequency analysis, open-circuit voltage, and determination of optimal load, voltage and power under load using experimental and numerical methods. The numerical results are obtained using the FEM software COMSOL Multiphysics 5.3a. From the frequency analysis of various beams by experimental and numerical analysis, it was found that the maximum deviation is about 4.18%. In the open-circuit voltage, TA TW and INTA TW energy harvesters have a minimum and maximum deviation of 0.77% and 9.92% with experimental and numerical methods. From the numerical and experimental results, it was found that the INTA TW energy harvester produces an averagely of 15.63% more power per unit volume compared to the RE energy harvester. From this investigation, it was found that the numerical method has good agreement with the experimental method. [ABSTRACT FROM AUTHOR]

The field of wireless sensors and portable electronics devices gained more attraction and growth over the years. Almost all the devices are powered using chemical batteries. Several energy sources are available in the environment in different parameters, which could be able to convert into an electrical parameter to power the portable devices and wireless sensors. This article reviews the harvesting of vibrational energy and converting it into electrical energy using piezoelectric materials. The sources of energy and conversion mechanism used to convert one type of energy into electrical energy were discussed. The different types of piezoelectric materials, various geometries of the substrate, resonant tuning methods of the harvester, placement of piezoelectric materials, and proof mass on the substrate were also reviewed. [ABSTRACT FROM AUTHOR]

This paper presents the design and development of manual frequency tuneable energy harvester. The energy harvester consists of beam, piezoelectric materials, proof mass, charging circuit, storage device and enclosure box. The design of beam and proof mass was made using the output of previous work and other parts were designed in this work. The energy harvester was developed based on the design and placed into the enclosure box. The fabricated model was tested to know the performance of energy harvester by analysing the output voltage, current, power and charging time of the battery. The distance of proof mass was varied from the fixed end of the cantilever beam to tune the frequency of energy harvester. From the experiment, it was found that the proof mass of energy harvester at 115 mm produced 88.77% more power compared to the proof mass placed at 85 mm from the fixed end. The operating range of energy harvester is about 5 Hz to 30 Hz. The proof mass placed at a distance of 155 mm from the fixed end charge the 60 mAh battery at 65.14% faster compared to the proof mass placed at 85 mm from the fixed end. [ABSTRACT FROM AUTHOR]

• Effect of placement of piezoelectric material over the length of a cantilever beam was analysed. • Effect of different proof mass material and volume on the performance of energy harvester were analysed. Effect of different orientation of proof mass volume on the performance of energy harvester was analysed. • Maximum power was produced, while the piezoelectric material was placed near to the fixed end. • The material and volume of the proof mass does not have any significant effect on the power output and resonant frequency of the beam. • The placement of the proof mass has a 10.9% effect on the resonant frequency of the beam and shape of the proof mass has 1.9% effect on the power output. This paper presents the effect of placement of piezoelectric material over the length of a cantilever beam based energy harvester. The effect of the material, volume, shape, size and placement of the proof mass were also analysed using COMSOL Multiphysics 5.3a. The distance between the piezoelectric material and the fixed end was varied over the length of the beam. Maximum power was produced, while the piezoelectric material was placed near to the fixed end. The resonant frequency of the beam is decreased, when the distance between the piezoelectric material and the fixed end is increased. The resonant frequency of the energy harvester and the voltage output at various conditions were numerically and experimentally verified. From the numerical analysis, it was found that the material and volume of the proof mass does not have any significant effect on the power output and resonant frequency of the beam. The size of the proof mass has 1.9% and 0.8% effect on the power output and resonant frequency of the beam respectively. The placement of the proof mass has a 10.9% effect on the resonant frequency of the beam and shape of the proof mass has 1.9% effect on the power output. [ABSTRACT FROM AUTHOR]

This paper presents various designs of the cantilever based piezoelectric energy harvester, which is excited using mechanical vibrations at the fixed end. By varying the geometries of the cantilever beam; higher stress, strain and consequently higher voltage and power could be attained from the same piezoelectric material. The analysis of energy harvesters were done using COMSOL Multiphysics 5.3a. The stress, strain and frequency response of the beams were verified by analytical, numerical and experimental methods. The result shows that the inverted taper in thick and width and inverted taper in width types of beams generated 47.39% and 21.31% more power compared to the rectangular cantilever beam. The resonant frequency of the inverted taper in thick and width beam is 53.3% less than the rectangle beam. [ABSTRACT FROM AUTHOR]

• LiFe 5 O 8 thin films exhibits specific discharge capacity of 25 μAh/cm2 at 10 μA/cm2 current density. • Li-ion diffusion coefficient during the de-lithiation and lithiation process is seen to be 3.78 × 10−14 cm2/s and 1.41 × 10−13 cm2/s, respectively. • Li+ storage is dominated by a diffusion-controlled process at low scan rates and it becomes a surface-controlled process at high rates. The search for obtaining a Co free low-cost and high-capacity anode thin film material for high energy density all-solid thin film batteries has been driving the increasing innovation and research in Li-ion battery (LIB) technology. In the present case, LiFe 5 O 8 (LFO) thin films are prepared by pulsed laser deposition (PLD) technique and their electrochemical properties, Li ion dynamics, conducting processes at various frequencies and current rates are explored. LFO thin films are seen to crystallize in ordered α -phase with an inverse spinel structure. Chemical state of all the elements is analysed using X-ray photoelectron spectroscopy method. Cyclic voltammeter (CV) study carried out between 0–3 V shows the reduction peak at 0.76 V initially and in the later cycles at 0.86 V with a small shift depicting the exact conversion type behaviour of the LFO thin film. LFO thin film exhibits specific discharge capacity of 25 μAh/cm2 at 10 μA/cm2 current density during the first cycle. Rate capability measurements are carried out at various current densities of 10, 20, 30, 40, 50 and 10 μA/cm2. Li-ion diffusion coefficient during the de-lithiation and lithiation process is seen to be 3.78 × 10−14 cm2/s and 1.41 × 10−13 cm2/s, respectively. CV studies at various scan rates indicates that the mechanism of Li+ storage is dominated by a diffusion-controlled process at low scan rates and with increasing scan rate it becomes a surface-controlled process. Electrochemical impedance studies at various frequencies shows the decrease in charge transfer resistance with increasing cycles. Combined structural, chemical, electrochemical and impedance studies of LFO thin films indicates that these films can be employed for fabricating Co and Ni free all-solid thin film Li-ion batteries for energy storage applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Steady, laminar flow of an incompressible fluid with mixed convection over an isothermal circular cylinder is considered. The governing full nonlinear Navier–Stokes equations with energy equation are solved by using a high-accuracy finite difference scheme in cylindrical polar coordinates. The results are discussed in detail for 5 ≤ Re ≤ 40, 0.7 ≤ Pr ≤ 7, and 0 ≤ Ri ≤ 4 and the results are in agreement with the experimental and other computed data. An increase in the mixed convection parameter leads to reduction of the drag coefficient. The fluid with higherPrgenerates vortices that destabilize the flow. The localNufor the mixed convection cases are higher than the pure forced convection counterparts. The normalized mean Nusselt number (Nm) does not significantly change for flows with very small Richardson numbers. However, for largerRi, it increases linearly withRi. [ABSTRACT FROM AUTHOR]

Vibratory feeders are commonly used in industries for part feeding. There are several factors that affect the conveying velocity of parts on the vibratory feeder. Among these, the critical factors such as excitation frequency, amplitude of vibration, mass of part, co-efficient of friction and Length-towidth (L/W) ratio of the part were considered for experimental studies. The percentage of influence of each factor on conveying velocity was determined through ANOVA. Regression and Artificial Neural Network (ANN) models were developed to predict the velocity of prismatic parts on vibratory feeder. Comparison of results with experimental results revealed that ANN was able to predict closer than the regression model. [ABSTRACT FROM AUTHOR]

Vibratory feeders are commonly used in industries for part feeding. The design of vibratory part feeders is complex and consumes more time. Sensorless part feeding (without the aid of sensors) is further challenging. Berretty et al (2001) discussed a sequence of mechanical barriers which either reject the disoriented parts or reorient the parts to desired orientation. They termed this as 'traps'. In this paper, an inexpensive trap was designed and fabricated for handling brakeliners. The efficiency of the trap was found to be 100% using Markov model as well as experimental results. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dielectric constant of LiFe 5 O 8 increases from 2 × 104 to 3 × 106 with Sr doing. • Dielectric loss decreases considerably with Sr doping in LiFe 5 O 8. • Grain and grain boundary contributions to the conductivity in Sr doped LiFe 5 O 8 is evident. We report on enhanced dielectric constant and reduction in dielectric loss with Sr doping in LiFe 5 O 8 bulk material. LiSr x Fe 5-x O 8 (x = 0, 0.025, 0.05) samples are seen to crystallize in ordered α- LiFe 5 O 8 phase. Dielectric constant is observed to increase from 2 × 104 to 3 × 106 and loss decreases with the doping of Sr at Fe site. Temperature dependent DC conductivity follows the Arrhenius relationship and the activation energy associated with the conduction process is seen to be 0.42, 0.41 and 0.52 eV for the LiSr x Fe 5-x O 8 (x = 0, 0.025, 0.05) samples. Temperature and wide frequency dependent dielectric measurements indicate that the Sr doped LiFe 5 O 8 samples exhibit relaxation behavior and can be employed for high frequency applications. [ABSTRACT FROM AUTHOR]

A prominent problem in manufacturing automation is the accurate and reliable presentation of small parts, in a single specified configuration called preferred orientation, to a work cell. This is often referred to as the "part feeding" problem. Low cost automation is employed to develop the part feeding system for brake liner, a typical asymmetric part. Currently handling of such asymmetric parts is done either manually or by using expensive robot and vision systems. These approaches cumulatively increase the production cost. The proposed low cost part feeder system uses sensor less mechanical devices or barriers such as slot, wiper blade, balcony, edge riser etc. to eliminate or reorient the arbitrary orientation into a preferred orientation which facilitates stacking. A complete set of such mechanical devices is called trap. The orientation with highest probability of occurrence is found using drop test, which is the preferred orientation at the exit of the feeder. A trap is designed to get the preferred orientation at the exit of the feeder. Critical dimensions of the trap were identified and experiments were conducted to optimize them. [ABSTRACT FROM AUTHOR]

• LiSr x Fe 5−x O 8 (x = 0, 0.025, 0.05) samples exhibit magnetic anomalies. • Curie temperature of LiSr x Fe 5−x O 8 (x = 0, 0.05) samples are very high (950 and 930 K). • LiFe 5 O 8 undergoes a soft to hard magnetic behavior with Sr substitution. ga1 We report on magnetic anomalies at low temperatures, high Curie temperature values, structural and chemical properties of Sr doped LiFe 5 O 8 bulk material. Micron size LiSr x Fe 5−x O 8 (x = 0, 0.025, 0.05) are seen to crystallize in ordered α-LiFe 5 O 8 phase with the space group of P4 3 32. Chemical states of Li, Fe, Sr and O are confirmed from X-ray photoelectron spectroscopy measurements. Domain wall thickness is calculated to be 60 nm, 59.4 nm and 52.5 nm for x = 0, 0.025, 0.05 samples respectively. Field cooled (FC) and zero field cooled (ZFC) measurements from 300 K to 15 K shows several anomalies in LiSr x Fe 5−x O 8 (x = 0, 0.025, 0.05) samples. Magnetic anomalies are observed at T m1 (275 K), T m2 (225 K), T m3 (125 K), T m4 (80 K) and T m5 (30 K) for the pure LiFe 5 O 8 sample and for the Sr doped samples, two sharp jumps in magnetization are observed around T m6 (250 K) and T m7 (75 K). Saturation magnetization and Curie temperature values are seen to decrease with the partial substitution of Sr2+ ions for the Fe3+ ions in α-LiFe 5 O 8 structure. Remanent magnetization, magnetocrystalline anisotropy constant (K 1) and coercivity values are seen to increase with increasing Sr concentration. LiSr x Fe 5−x O 8 (x = 0, 0.025, 0.05) samples exhibit magnetic anomalies at low temperatures and exhibit hard magnetic behavior with Sr substitution. [ABSTRACT FROM AUTHOR]