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Open Access
Effect of artificially included defect on mechanical and fracture properties of Al 7075-T651 MIG welded butt joint
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Joshi, Shomesh; Gope, P.C.
Aluminium 7075-T651 is one of the widely used materials for various applications in industry, aerospace, utensils, etc. In the present investigation, fatigue crack growth on CT specimenand tensile experiments are performed on MIG welded butt joint of aluminium 7075-T651 with artificially included defect of carbon nanoparticles with Pmax= 5 kN, Pmin= 0.5 kN, frequency of 6 Hz and R=.1 under constant amplitude loading and under universal testing machine of 25 kN. The experimental data obtained has been used to plot a-N, da/dN vs. 􀀧K curve, stress-strain curve and Paris crack growth constants. The fatigue life is found to be 25500,22400,29500 and 27800 cycles respectively for MIG welded CT specimen with single V-notch without defect, single V-notch with defect, double Vnotch without defect and double V-notch with defect respectively for across weld region. But for the along the weld region for the same conditions mentioned above the life came out are 27300, 23500, 31200, 26900, respectively. Also, the ultimate strength is found to be 244.70, 208.31, 274.6, 259.8 MPa for the single V-notch without defect, single V-notch with defect, double V-notch without defect and double V-notch with defect respectively for along weld region. Moreover, for the across the weld region for the same conditions mentioned above, the ultimate strength comes out to be 211.18, 200.12, 242.02, 234.56 MPa, respectively. The values of material constants C and m are calculated through single Paris Curve fit. Mathematical modelling is also done for the above study to find out the trend of the fracture properties and the ultimate strength with respect to the percentage of the defected area in the weld.
Open Access
Simulation of vapor compression-absorption refrigeration system
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Chauhan, Ritik; Pratihar, A.K.
The compression-absorption refrigeration systems has been considered to be the possible replacement of the vapor compression and vapor absorption refrigeration system due to their useful features like better capacity control and its operation at low-pressure levels in the system due to the use of mixtures and higher coefficient of performance compared to vapor compression system. In the present work, thermodynamic analysis of compression-absorption system has been carried out for milk chilling application at 4 ℃. In order to study the performance of system computer simulation of actual system has also been carried out where effect of some important parameters on the coefficient of performance of the system has been studied using Warner’s method. In the simulation of absorber and desorber fourth order Runge-Kutta method has been used. A COP of 4.435 has been obtained at a compression ratio of 4.0, desorber temperature of 8°C, an absorber pressure of 20 bar, maximum concentration of 0.8. It is observed that the exergetic efficiency increases with the decrease in desorber temperature and exergetic efficiency decreases if the value of compression ratio increases. Simulation has been performed for three different lengths of absorber and desorber, 5.0 m, 7.0 m and 10.0 m and three different relative area of solution heat exchangers area, 10%, 20% and 30%. The effect of the mass flow rate of the weak solution, length of absorber and desorber and relative area of solution heat exchanger on the COP, cooling capacity and absorber heat load has been studied. The results show that the COP of the system can be increased by maintaining a low mass flow rate of the weak solution, large relative area of solution heat exchanger and a large absorber and desorber length. From simulation it is found that COP of the system attains a maximum value at a given mass flow rate of weak solution. By increasing the length of absorber and desorber from 5 m to 10 m, the COP of the system increases from 2.96 to 3.25 i.e. an increase of 9% is attained.
Open Access
Performance comparison of solar cooker using different phase change materials during off sunshine hours
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Abhishek Kumar; Bhandari, Susheel Singh
The continuous increase in the level of greenhouse gas emissions and the increase in fuel prices are the main driving forces behind efforts to more effectively utilize various sources of renewable energy. In many parts of the world, direct solar radiation is considered to be one of the most prospective sources of energy. Energy requirement for cooking accounts for 36% of total primary energy consumption in India. Hence, there is a critical need for the development of alternative, appropriate, affordable mode of cooking for use in developing countries. However, the large scale utilization of this form of energy is possible only if the effective technology for its storage can be developed with acceptable capital and running costs. Solar cooker is the best way to utilize solar energy. In the present work thermal performance of a box type solar cooker has been evaluated according to the bureau of Indian standard (BIS). The BIS suggested two test for evaluation of thermal performance. The first test is stagnation test for evaluation of first figure of merit F1.The second test is full load test for the determination of second figure of merit F2. The first figure of merit is obtained by conducting the stagnation temperature test without load for empty box type solar cooker. The first figure of merit is the ratio of optical efficiency to heat loss factor. The second figure of merit is obtained by sensibly heating a known amount of water and it is a measure of heat exchange efficiency factor of a box type solar cooker. The variation in second figure of merit is also studied by increasing load and number of pots. It is found from experimental study that second figure of merit increases with load and number of pots. The value of figure of merit imply that the cookers are identical and satisfy BIS standard. The performance comparison of solar cooker using different phase change materials during off sunshine hours is main emphasis of the present experimental study. Cookers are also studied using modified finned cooking vessel. Three different phase change materials paraffin wax, stearic acid, lauric acid are selected. It is found from experimental studies that finned cooking vessel increases efficiency and reduces the cooking time. Paraffin wax is best phase change material to store latent thermal energy during sunshine hours and to retrieve back its conserve energy to thermic fluid water during off sunshine hours.
Open Access
Experimental studies on a double slope single basin solar still using sensible heat storage materials
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Negi, Pankaj; Varshney, Lokesh
Many countries are facing a shortage of potable water, as the population is increasing rapidly. Most of the water present on earth’s surface is in oceans and lakes which is either saline or brackish water. This water can solve water-related issues by converting it into potable water through desalination process. Many people are suffering from water-borne diseases by consuming contaminated water, therefore there is an essential requirement of potable water production technology for its distillation. Solar energy is cheap and easily available and can be utilized for converting saline water into potable water. Solar still is a device which uses solar energy to convert saline water into distilled. Productivity of conventional solar still is found to be low. Attempts have been made by researchers to improve the productivity of solar still. Present work is an attempt to increase the productivity of double slope single basin solar still by utilizing sand bed as sensible heat storage material beneath the basin of solar still. Experiments have been conducted for sand bed of thickness 0.5 and 1.0 cm and furthermore for mixing engine oil (SAE 20W40) with the sand bed of thickness 0.5 cm up to saturation limit for filling voids and minimizing contact resistance for heat transfer between basin and storage bed. Intermittent glass cover cooling has also been done for reducing the temperature of the glass cover and increasing the amount of condensate. Results of experiments revealed that daily productivity of solar still is increased by utilizing sand bed beneath the basin of solar still. Daily productivity of still increased by 10.72% and 3.16 % by utilizing 0.5 and 1.0 cm thick sand bed respectively for basin water depth 0.6 cm. There is an increment of 11.16 % in daily productivity of modified still with a 0.5 cm thick sand bed by intermittent glass cover cooling. Daily productivity of solar still modified with 0.5 cm thick sand bed increases by 6.16 % by mixing engine oil in the sand bed.
Open Access
A wideband microstrip patch antenna with single band-notch characteristic using defected ground structure
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Singh, Prabhat; Paras
With the rapid growth of wireless communications in recent years, users need multiple frequency bands at the same time to access different services such as voice video and data. Therefore, it has become to have microstrip antenna (MSA) with a wide band to avoid employing multiple antennas to fulfil requirement of the users. The MSA is a revolution in the field of wireless applications due to its low cost, ease of installation, performance and low profile structure which make it a high quality contender. for many communication equipment. The main objective of this proposed work is to develop a wideband microstrip antenna using band-notch characteristic with DGS for wireless applications in the frequency range of 3.3-11.5 GHz. The proposed antenna is designed using Cavity model and is simulated and optimized using HFSSv.15 with a centre frequency of 5.3 GHz. Proposed antenna is used to operate at the frequency range of 3.3-11.5 GHz in wireless applications like WiMAX (3.6 GHz), Hi-LAN (5.15-5.35 GHz), WLAN IEEE802a (5.2 GHZ), and DSRC for a car to car communication (5.850-5.925 GHz) but band-notch characteristic used to reject band at frequency range (5.1-5.8). A 5.1-5.8 GHz might be used for WiMAX and other wireless applications. The proposed antenna is fabricated on a FR4 substrate having thickness 1.6 mm and loss tangent of 0.02. The fabricated antenna has dimensions 35×32.9×1.6 . The parameters in terms of reflection coefficient and VSWR for the proposed antenna (fabricated) are measured and compared with the simulated ones, which show good agreement. The proposed antenna is also compared with the earlier designed antennas. The measured broad bandwidth with reflection coefficient below -10 dB is found to be 8200 MHz in the frequency range from 3.3-11.5 GHz. Simulated peak gain of 8.92 dBi and radiation efficiency of 90-98% for the proposed antenna in the frequency range from 3.3-11.5 GHz are observed. The proposed antenna has a stable radiation pattern in both E and H planes.
Open Access
Design and development of band notched antenna with DGS for UWB applications
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Sharma, Himanshu; Paras
In the present day scenario the need for wireless communication is increasing in order to support more users and to provide more information with higher data rate. Ultra wideband is a wireless technology used for high speed data transfer over short distances. But in the ultra wideband frequency band there are some other frequency bands like WLAN, WiMAX, C band, X band etc. which may cause interference with the ultra wideband . Therefore notching technique is used in order to remove the interfering band from the ultra wideband range. In the proposed work a dual band-notched antenna with DGS for ultra wideband applications is designed and fabricated. Size of the proposed antenna is 36 x 33 x 1.6 mm3 and FR-4 is used as the substrate for the proposed antenna. Antenna is resonating in the frequency range of 2.5-12.5 GHz with peak gain of 5.47 dBi giving total bandwidth of 10 GHz. Antenna is having two band notches from 3-4 GHz and 6.95-7.8 GHz removing the WiMAX and XSCS band from the ultra wideband range. Simulation of the antenna is done in HFSS and fabrication of the antenna is done using PCB designing machine. Testing of the antenna is done using vector network analyser (VNA).
Open Access
A robust 11T SRAM cell with improved SNM in 22nm technology
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-08) Singh, Urwashi; Sharma, K.K.
Static Random Access Memory (SRAM) is fundamental memory block used as caches in computers, processors and battery operated devices. In this proposed work, simulation study of different SRAM cell is carried out using Complementary Metal Oxide Semiconductor (CMOS) and Fin shaped Field Effect Transistor (FinFET) 22nm technology at the supply voltage of 0.8V with HSPICE tool. As the technology scaled in nanometer range, the Short Channel Effects (SCEs) causes degradation in the performance of the CMOS devices. This SCE is minimized by using FinFET devices at lower technology node. The performance metrics such as Hold SNM, Read SNM, Write SNM, access time, Static and Dynamic power is evaluated to check the behaviour of existing SRAM cells in 22nm node. A new 11T SRAM is also proposed and its performance metrics are calculated in both CMOS and FinFET 22nm technology. The simulation results of proposed 11T SRAM Cell is compared with existing SRAM cells. The proposed11T SRAM Cell achieves hold and read SNM as 285mV and write SNM as 336 mV in CMOS technology whereas the hold, read and write SNM in FinFET technology is 360mV, 360mV and 375mV, respectively. The proposed SRAM cell has shown enhanced SNM due to isolation of read and write path. The second important parameter, static power is 3.72nW in CMOS technology and 0.49nW in FinFET technology. Because of reduction in static power and improved SNM the proposed 11T SRAM cell can be used in low power high stability applications such as smart phones, LCD displays and CPU processor.
Open Access
Investigation of the performance of three phase induction motor under non sinusoidal supply voltages
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2019-09) Kaushik, Deepak; Srivastava, Ajay
According the electric power research in 1995, 35- 40% of all electric power flow through electronics converters. That used of electronics devices increased year by year. All the electronic converters are the non- linear load and they generate the harmonics. Harmonics affects the power supply, it affects the voltage, current, and frequency of the power supply and power supply become distorted. The distorted power supply affects the performance of all connected devices. Induction motor is mostly used machine in industrial area as well as commercial area. Induction motor performance also affected by the distorted supply, therefore the study about the performance parameter of induction motor like torque, speed, power factor, torque ripple, losses, efficiency etc. under the distorted supply on MATLAM/SIMULINK. SIMULATION give the quick analysis of the performance parameter, under the positive, negative, and mix harmonics to check the performance of motor under different loading condition. At harmonic contain supply under full load condition efficiency and power factor was increasing with decreasing in harmonic voltages. That observation is same for positive, negative and mix harmonics. But the change is very minor in efficiency and power factor. Speed does not vary with harmonics supply. Ripple is constant for all load at different harmonics. Losses increase due to the harmonics contain supply.
Open Access
Effect of crop and machine parameters on threshing effectiveness and seed quality of basmati rice
(G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2004-07) Chauhan, Shiv Sankar; Gupta, O.P.
Basmati rice is becoming popular all over world. Indian Basmati rice fetches three times higher price than other countries. Recently it was reported that threshing reduces the quality of Basmati rice. Experiment was conducted to study the threshing effectiveness on Basmati paddy. The experiment was conducted on an axial flow multicrop thresher with three varieties of Basmati and one coarse varieties of paddy, with four levels of cylinder speed, three level of moisture content and three level of feed rate. The threshing efficiency was found 100%. Result showed that grain damage and cleaning efficiency increased with the increase in cylinder speed. Maximum grain damage was 0.9% in Pusa Basmati-1 and Basmati-1121 respectively at cylinder speed of 18.21 m/s, moisture content 25.1 per cent and feed rate 960 kg/h. Grain damage of Taraori Basmati, Pusa Basmati-1 and Basmati-1121 is higher than Pant Dhan-12 by 7.3, 19.5 and 24.4 per cent respectively. The cleaning efficiency varied from 91.7 to 99.1% for all the varieties at all cylinder speed, feed rate and moisture content. The maximum cleaning efficiency was observed to be 99.1 percent for Basmati-1121 and minimum 91.7% in case of Pant Dhan-12. Germination percentage was above 80% in all the variety except Pusa Basmati-1. The effect of cylinder speed, moisture content and feed rate were analysed statistically on grain damage, cleaning efficiency and germination percentage. Result showed that effect of these parameters have significant effect. Overall working of thresher was found satisfactory for the selected variety and parameters under study.

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