Dav Institute of Engineering and Technology

This study presents an approach to generate terahertz radiation using two Hermite- Cosh- Gaussian lasers co-propagating along the z-axis and polarizing along the y-axis. The interaction of these lasers with plasma in the presence of a static magnetic field along the x-axis and oscillating at the cyclotron frequency induces a ponderomotive force. This force, in turn, produces nonlinear velocity and current density within the plasma. It is demonstrated that this nonlinear current density acts as a source for THz radiation. The feasibility of the magnetic field parameters is discussed in light of practical experimental conditions The main aim of this study is to analyze the relationship between THz conversion efficiency, normalized transverse distance, cyclotron frequency plasma frequency, and laser parameters like Hermite polynomial mode index (m), decentered parameter, etc. Key findings reveal that the terahertz signal amplitude diminishes rapidly under off-resonant conditions and approaches zero as the normalized THz frequency exceeds 5. The results highlight the potential of optimizing the decentered parameter and Hermite polynomial mode index to develop energy-efficient, powerful, and customizable THz radiation sources. By bridging theoretical insights with experimental relevance, this work contributes meaningfully to advancing THz science and technology.

This study investigates terahertz (THz) radiation generation through the interaction of two laser beams with a mixture of graphite nanoparticles with different shapes and orientations in the presence of external fields. The interaction induces a nonlinear ponderomotive force, creating a nonlinear oscillating current when the laser beat frequency ($\omega _1 - \omega _2$) matches the surface plasmon resonance frequency of the nanoparticles. The presence of an external wiggler magnetic field significantly enhances the efficiency of THz radiation by providing the necessary phase matching and momentum, resulting in an approximately sixfold increase in the enhancement of terahertz amplitude. Additionally, applying a transverse static electric field further enhances the amplitude of THz radiations, but to a lesser degree. This study aims to address the limitations of traditional THz generation methods and provides new insights into optimizing the efficiency of THz generation by utilizing amplitude-modulated laser beams, nanoparticle configurations, and the application of external fields. The findings of this study pave the way for compact, high-power THz sources with enhanced efficiency and tunability for practical applications.

The integration of Internet of Things (IOT) technology with biomedical devices has revolutionized the field of healthcare by enabling remote diagnosis and continuous monitoring of patients. This chapter explores the innovative applications of IOT in biomedical devices for remote diagnosis and monitoring. It discusses the principles, challenges, and benefits of IOT-enabled healthcare devices, highlighting their impact on patient care and healthcare systems. This chapter also delves into real-world examples of IOT-based biomedical devices, their architecture, data communication, security measures, and potential future developments.

The study investigates the generation of terahertz radiation by two Hermite-Cosh-Gaussian laser beams in collisionless magnetized plasma in a tapered magnetic field. A tapered wiggler magnetic field is applied perpendicular to the propagation direction of the beams. The externally applied magnetic field produces Lorentz force, which alters the dynamics of the oscillating electrons, leading to modifications in the plasma wave. The force generates nonlinear velocity and nonlinear current density within the plasma, resulting in efficient Terahertz generation. The study analyzes the effect of normalized transverse distance, tapering parameter, cyclotron frequency, plasma frequency, and other laser parameters such as Hermite polynomial mode index (m) and decentered parameter on the terahertz conversion efficiency. The results show that the terahertz amplitude significantly increases with wiggler magnetic field strength, mode index, decentered parameter, and laser intensity and decreases with tapering parameter. The innovative approach demonstrates practicality in creating powerful, customizable, and energy-efficient terahertz radiation sources by optimizing the values of the decentered parameter and Hermite polynomial mode index. Also, the plasma wiggler approach provides a promising avenue for generating high-energy, tunable terahertz waves.

The agriculture industry is critical to the global economy, with product quality having a direct impact on marketability and waste management. Apples, one of the most extensively produced fruits, are affected by a variety of diseases that can reduce productivity and quality. Accurate diagnosis of diseases is critical, but traditional manual approaches are time-consuming, error-prone, and ineffective. Inadequate labeled data and a wide range of disease symptoms make it necessary to design an automated, robust, and accurate system. This article describes a hybrid model for Apple Fruit Disease Detection (HMAFDD) that combines the strengths of three pre-trained convolutional neural network (CNN) models: ResNet50, DenseNet121, and EfficientNetB0. It accomplish this by using multi-architecture feature extraction. The hybrid system, which combines both models, is able to recognize a wide range of features, from simple textures to complex patterns unique to a certain diseases. Grad-CAM, or gradient-weighted class activation mapping, creates heatmaps that highlight significant regions for prediction, which enhances the interpretability of the model.To increase robustness and accuracy, techniques such as spectral-shifted adversarial perturbation for data augmentation and spectrally-weighted global average pooling for feature aggregation are used. This technique provides 99.75\% accuracy with minimal processing needs, making it acceptable for real-time applications in agricultural situations. This considerably improves apple disease management.

The study investigates the impact of gamma radiation on the optical, structural and electrical properties of Polyaniline (PANI) and Polyvinyl Chloride (PVC) composites having 30% PANI concentration exposed to varying doses of gamma radiation (25–100 kGy). The multiple peaks in PL spectroscopy and shift in the UV–Vis absorption band towards lower wavelengths indicate chain scissoring due to gamma radiation. The increase in amorphous behavior of the composites with increasing irradiation doses is confirmed by an increase in Urbach’s energy and XRD spectra. FTIR analysis indicates chain scissoring and free radical production in PVC chains. SEM images revealed surface modification as is evident from the formation of clusters and rods.

We have investigated the generation of terahertz radiation due to the beating of two Hermite Cosh Gaussian (HchG) laser pulses in the presence of frequency chirp in a plasma. These two HchG lasers have electric fields $\vec{E}_{1}$ and $\vec{E}_{2}$ co-propagating along the z-axis with frequencies $\omega_{1}$ and $\omega_{2}$ with their propagation constants $k_{1}$ and $k_{2}$, and polarized along the y-direction. Plasma electrons are subjected to nonlinear ponderomotive force due to lasers beating in plasma. Because of this, plasma electrons acquire an oscillatory velocity in the presence of frequency chirp, producing a great transient transverse nonlinear current. This nonlinear current is responsible for the production of generation of terahertz radiation with higher efficiency. The results reveal that the THz field profile heavily depends on laser parameters like the chirp parameter b, decentred parameter d, and mode index m of Hermite function and an amplitude of ∼0.8 has been attained with an optimized set of laser and plasma parameters. This study aims to revolutionize Terahertz (THz) radiation generation by utilizing plasma’s robustness as a nonlinear medium, surpassing the limitations of conventional methods. Utilizing two Hermite Cosh Gaussian (HchG) lasers with frequency chirp, we explore enhanced efficiency in THz output by optimizing laser-plasma interactions. The focus is on understanding the nonlinear ponderomotive force on plasma electrons, elucidating how chirped lasers amplify THz radiation. Through rigorous numerical analysis, this research provides crucial insights for developing advanced THz technologies with superior performance and applicability in diverse fields such as imaging and spectroscopy.

The book chapter “Renewable Energy and Sustainable Transportation” delves into the intricate interplay between renewable energy solutions and the transformation of transportation systems toward sustainability. It explores the profound impact of shifting from fossil fuels to renewable sources such as solar, wind, and hydroelectric power on reducing greenhouse gas emissions and mitigating climate change. The chapter also delves into the integration of electric vehicles and advanced biofuels, showcasing their potential to revolutionize transportation by minimizing air pollution and decreasing dependence on finite resources. Through a comprehensive analysis of policy frameworks, technological advancements, and real-world case studies, this chapter offers valuable insights into the symbiotic relationship between renewable energy adoption and the establishment of eco-friendly transportation networks. Readers will gain a deeper understanding of the challenges, opportunities, and synergies that emerge at the nexus of renewable energy and sustainable transportation, ultimately contributing to a cleaner and more resilient future.

Given the variety of networks, interfaces, mediums, and other resources accessible in a wireless heterogeneous location today, mobile communication is in a healthy competitive environment. When clients or users have access to numerous interfaces at once, a problem occurs. Users therefore require a clever or intelligent system to connect them to the finest services based on their needs and choices. Interface management controls the interfaces that are accessible and links the user to the best. The intelligent usage of various radio accesses/interfaces is made possible in this research by interface management with artificial neural networks (ANNs). Various parameters of different networks are used to make the choice. In this paper, a back propagation neural network (BPNN) method for switching between 3G, WLAN, 4G, and 5G networks is suggested. By allocating appropriate weights, the various network properties are employed as selection parameters. Fuzzy Analytic Hierarchy Process (FAHP) is used to initialize the weights, and the BPNN is used to optimize them. In order to obtain the best value, the goal value and the original value are compared, and the difference between them is used as an adjusting value for the weights. The network is trained using backpropagation techniques. The comparison between the proposed algorithm and the current algorithm demonstrates the new method's flexibility and the network's optimal connectivity with a high rate of successful handovers.

An analytical model of second-harmonic generation (SHG) from amplitude-modulated laser-irradiated carbon nanotubes (CNTs) implanted in silica substrate is presented. In the interaction of an intense amplitude-modulated laser with an array of magnetized anharmonic CNTs, a force is exerted on the electrons of CNTs due to the electric field of the laser. The exerted force causes the displacement of the electrons which is of the order of the radius of CNTs due to their nanoscale dimensions. In turn, the restoring force of the electrons becomes a nonlinear function of the displacement and results in anharmonicity. The CNTs are magnetized by applying the magnetic field perpendicularly to the beam propagation direction. The anharmonicity in CNTs broadens the plasmon resonance. The effects of the amplitude-modulated parameter and CNTs parameters on the amplitude of the second harmonic are analyzed. The magnetic field also helps to enhance the power of generated second harmonic.

Acid Mine Drainage (AMD) mainly occurs as a result of the natural oxidation of Iron-sulfide minerals contained at operating or closed/decommissioned mine sites, which is one of the most significant environmental challenges faced by the mining industry people worldwide. AMD adversely affects the surrounding land use and water quality due to its typical low pH, elevated concentration of metals, reactive sulfide content, and high acidity. This study presents a state-of-the-art review of the Geochemical, Microbial, and Environmental aspects of AMD generation, collection, and cost-effective options for its treatment (source control to minimize acid generation, implementation of mitigation control, and treatment). This paper also provides an overview of Constructed wetlands (CWs) and phyto remediation options that could provide efficient passive low-cast viable treatment options with a higher percentage of sulfide reduction, removal of other metals, and alleviation of extreme acidic conditions for the developing, operating as well as closed/decommissioned mines. Thus, indigenous aquatic macrophytes and microbial communities that immobilize, bio-leach, or accumulate a small number of metals in constructed wetlands treatment could effectively contribute to the remediation of acidic metal-contaminated runoff waters from mines and mine waste processing/disposal areas. Thus, indigenous aquatic macrophytes and microbial communities based on an integrated constructed wetlands bioremediation approach may successfully lead to a cleaner, greener environment.

The rapid developments in the electronics industry and advancements in semiconductor fabrication techniques brings a unique emerging technology into the light called E-textiles or smart textiles. It is an integration of soft electronic components including smart sensors, controllers, batteries, antenna, and like-wise on the wearable textile or clothing. Thanks to the flexible soft circuitry and sensors that are placed very close to the body, E-textiles can precisely monitor the physiological or vital signals of the user. The soft circuitry is embedded inside the user’s clothing and it is designed to monitor the wearer (user) activity by using sensors but without causing any discomfort to the wearer. Similarly, E-textiles can be used in automobiles to display a digital instrument cluster and other important information on the dashboard textile cover or can be used to warm the vehicle seats in cold temperatures. Further, E-textiles has a quite high scope in the decoration, sports and fashion designing industry. However, despite having such a high potential—E-textile technology is still undervalued and quite a little research conducted in this field. This paper aims to extract, analyse and provide a comparative study of research and related work done in the E-textile technology up to now as well as to provide a comparative study of manufacturing techniques, components, and controllers used in E-textiles. In addition, the application areas are proposed, where E-textile can be utilized. At the last, whitespace or area of interest recommended where further research can be focused.

Fifth‐generation wireless networks (5G) are defined to meet the requirements of high data rates for thousands of users, synchronized connections for vast wireless sensor networks, improved coverage area, efficient signal processing, low latency and enhanced network spectrum as compared to the fourth‐generation wireless networks (4G). These networks were initially envisioned for efficient and fast mobile networks along with converged fiber‐wireless networks. However, with the explosion of smart devices and emerging multimedia applications the need to roll out 5G networks to meet the demands both at the consumer and business end became necessary. Therefore, to create a network with faster speed, the 5G networks have initiated a new basis for communication, which consists of the Internet of Things (IoT) and Machine‐to‐Machine communication (M2M). The IoT and M2M have been able to overcome the major limitations of 5G to initiate multiple‐hop networks, making available high data rates to peers between several base stations and thereby reducing costs and initiating reliable security standards. Such a major deviation from the conventional design to involve large networks to support massive access by machine‐type devices (MTDs) sets special technical challenges for M2M. This chapter offers an outline of the main issues raised by the M2M vision along with a survey of the common approaches proposed in the literature to enable the coexistence of M2M devices and the challenges which need to be investigated.

We propose a theoretical analysis for the generation of efficient terahertz (THz) radiation by using the nonlinear interaction of an amplitude-modulated Gaussian laser beam with a vertically aligned anharmonic and rippled carbon nanotubes (CNTs) array. This array of vertically aligned carbon nanotubes (VA-CNTs) is embedded on the base of the dielectric surface. The VA-CNTs have been magnetized by applying a static magnetic field perpendicular to the direction of propagation of the Gaussian beam and along the length of CNTs. The amplitude-modulated Gaussian laser beam passing through the CNTs exerts a nonlinear ponderomotive force on the electrons of CNTs and provides them resonant nonlinear transverse velocity to produce the nonlinear current which further leads to the generation of THz radiation. The surface plasmon resonance condition in the presence of an externally applied static magnetic field (110to330kG) and anharmonicity both help in broadening the resonance peak. By varying the modulation depth of the incident Gaussian laser beam, one can use emitted THz radiation to produce the best quality holograms.

The present paper explores the terahertz (THz) generation by the interaction of obliquely incident laser beams with the array of vertically aligned anharmonic carbon nanotubes (CNTs) acting as dipole antennas. In the scheme, anharmonicity arises due to the nonlinear variation of restoration force on the various electrons of CNTs and it plays a key role in the enhancement of THz generation. The anharmonic CNTs help in broadening the resonance peak, which paves the way for the enhancement of the normalized THz amplitude. The laser beams incident obliquely on the close-packed array of vertically aligned anharmonic CNTs grown over the glass substrate and set oscillations in the CNTs so that each CNT act as the oscillatory dipole to generate THz radiation. The THz electric field shows enhancement at surface plasmon resonance frequency ω=ωp0.5(1+β)/ϵr, where β is the characteristic parameter of CNTs, ϵr is the relative permittivity of lattice and ωp is the plasma frequency. This scheme is quite suitable to generate THz radiations in the milliwatt range of optimized values of the laser and CNTs parameters. We also explore the impact of polarization, S-parameter, critical angle, and length-matching effects of CNT antennas on the THz generation.

An analytical model of second harmonic generation (SHG) from amplitude modulated laser irradiated carbon nanotubes (CNTs) implanted in silica substrate is presented. In the interaction of an intense amplitude modulated laser with an array of magnetized anharmonic CNTs, a force is exerted on the electrons of CNTs due to the electric field of the laser. The exerted force causes the displacement of the electrons which is of the order of the radius of CNTs due to their nanoscale dimensions. In turn, the restoring force of the electrons becomes a nonlinear function of the displacement and results in anharmonicity. The CNTs are magnetized by applying the magnetic field perpendicularly to the beam propagation direction. The anharmonicity in CNTs broadens the plasmon resonance. The effects of the amplitude modulated parameter and CNTs parameters on the amplitude of the second harmonic are analyzed. The magnetic field also helps to enhance the power of generated second harmonic.

Reducing the total, differential settlement and increasing adequate bearing capacity are the two basic requirements for the construction of high-rise buildings, bridges, nuclear power reactors and offshore rigs on soft soil. They cover an immense area all along the coastal zones in India and other parts of the world. This coastline contains marine soft silt and cohesive soils and a higher level of the water table. These areas’ major structure foundations are built on a piled-raft foundation. Stone columns (SC) are very widely used for widespread loads, circular tanks, embankments and fills. The combination of piles with SCs may give an effective solution to resist the total and differential settlements. The performances of raft supported by the composite system of the pile—SCs are investigated using three-dimensional analyses. Effects of material properties of SCs, the tensile strength of geotextile, area replacement ratio and raft thickness have been examined. Results show that strengthening the soft clay soil with SCs and geosynthetic encased stone columns (GESC) were effective in enhancing the bearing capacity of the raft and reducing the total and differential settlement of the composite column supported raft foundation.

Due to overexploitation of renewable resources, we have observed that some species are already extinct. So, the time demands conservation, reproduction and optimal utilization of these resources and the study of such problems. In this paper, a delayed stage-structured self-dependent two compartment (compartment-I contains immature fishes and compartment-II contains mature fishes) commercial fishery model with impulsive harvesting is proposed and analyzed mathematically as well as numerically. The aim is to manage the fishery resource system and that to extract maximum profit without the species become extinct. The proposed system is proved to have positive periodic solutions which are bounded, locally stable and permanent with certain conditions. Then by using optimal impulsive harvesting theory, the optimal harvesting time and optimal harvesting level have been obtained. At last, numerical simulation has been done to support the analytic results, along with comparative plots drawn for different values of harvesting effort E, maturation delay τ$\tau$ and impulsive period T.

The most critical feature of current energy management systems is ORPD, which is used to maintain safe and reliable working conditions for power networks. Currently, due to their economic and technological advantages, HVDC transmission systems are commonly used in modern electrical power systems. The incorporation of DC link introduces more complexity in ORPD computation. Therefore, an attempt is made to optimally place and size the UPFC. In the transmission network, the UPFC is an efficient multipurpose FACTS controller for handling the reactive as well as the physical power individually in a rapid manner. This paper plans to develop a new hybrid approach referred as Backtraping Assisted Elephant Herding Optimization (BAEHO), to address the RPD issues in a power system under unbalanced conditions. The introduced hybridized approach further determines the optimal position and size for placing the UPFC based on the constraints like the LSI, VDI, ATC, and C UPFC. Moreover, the proposed algorithm is proved for its performance in maintaining a better trade-off among multiple objectives, even under overloading conditions.

With the propelling high capacity demands, long band (L-Band) passive optical networks (PONs) are getting extra consideration nowadays and fault detection/Monitoring is becoming crucial because of high capacity PONs. Fault detection using reflective Fiber Bragg gratings and an additional amplified spontaneous noise (ASEN) source in conventional band (C-Band) are widely reported. However, ASEN and transmitter signals in the same wavelength band cause interference and incorporation of additional ASEN sources increases overall cost. Therefore, an economical, complexity reduced fault detection system is required in PONs. In this work, a fault detection/monitoring system is proposed for L-Band PON using C-Band ASEN from inline erbium doped fiber amplifier and dual purpose FBG i.e. (1) ASEN reflection for fault monitoring and (2) Pulse width reduction. A 4 × 10 Gbps L-Band PON is investigated over 40 km feeder fiber (FF) which serve 32 optical network units (ONUs)/λ at different input powers, PWB, laser linewidths, chirping profiles of FBG in terms of reflective power of FBGs, eye opening factor, correct bit reception rate and pulse width reduction efficiency (PWRE) respectively. Reflective power from FBG and correct bit reception rate, decrease with the increase in input power and laser linewidth respectively. Moreover, FBG after FF provide PWRE of 60%, 75.8%, 73.06%, 72.41% and 65.5% in case of no chirping, liner, quadratic, square root and cube root respectively. Proposed system can detect fault without affecting data rate in optical distribution network and ONU, also compensate PWB effects.