Maximum Power Extraction Control Algorithm for Hybrid Renewable Energy System

In this research, a modified fractional order proportional integral derivate (FOPID) control method is proposed for the photovoltaic (PV) and thermoelectric generator (TEG) combined hybrid renewable energy system. The faster tracking and steady-state output are aimed at the suggested maximum power point tracking (MPPT) control technique. The derivative order number (µ) value in the improved FOPID (also known as PI^λD^µ) control structure will be dynamically updated utilizing the value of change in PV array voltage output. During the transient, the value of µ is changeable; it’s one at the start and after reaching the maximum power point (MPP), allowing for strong tracking characteristics. TEG will use the freely available waste thermal energy created surrounding the PV array for additional power generation, increasing the system’s energy conversion efficiency. A high-gain DC-DC converter circuit is included in the system to maintain a high amplitude DC input voltage to the inverter circuit. The proposed approach’s performance was investigated using an extensive MATLAB software simulation and validated by comparing findings with the perturbation and observation (P&O) type MPPT control method. The study results demonstrate that the FOPID controller-based MPPT control outperforms the P&O method in harvesting the maximum power achievable from the PV-TEG hybrid source. There is also a better control action and a faster response.     

Improving post irradiation stability of high density polyethylene by multi walled carbon nanotubes

Sterilization of implants and other clinical accessories is an integral part of any medical application. Although many materials are used as implants, polyethylene stands unique owing to its versatility. Carbon nanotubes are being used as a filler material to enhance the properties of polyethylene. However, the role of multi walled carbon nanotubes (MWCNTs) as an effective antioxidant and radical scavenger in resisting the deteriorating effects of sterilization is yet to be studied in detail. The present work is aimed to investigate the mechanical properties and oxidation stability of irradiated high density polyethylene (HDPE) reinforced by MWCNTs with various concentrations such as 0.25%, 0.50%, 0.75% and 1.00 wt.%. The composites were exposed to ⁶⁰Co source in air and irradiated at different dosage level starting from 25 to 100 kGy and then shelf aged for a period of 120 days prior to investigation. The loss in toughness, Young’s modulus and ultimate strength at 100 kGy for 1 wt.% MWCNTs composite were found to be 21.5%, 20.3% and 19.2%, respectively compared to that of unirradiated composite. FTIR and ESR studies confirmed the antioxidant and radical scavenging potentialities of MWCNTs with increased concentration and irradiation dosage. It was found that by the addition of 1 wt.% MWCNTs into virgin HDPE, the oxidation index of the composite at 100 kGy was decreased by 56.2%. It is concluded that the addition of MWCNTs into polyethylene not only limits the loss of mechanical properties but also improves its post irradiation oxidative stability.     

Preparation,characterization and performance of cellulose acetate ultrafiltration membranes modified by charged surface modifying macromolecule

A charged surface modifying macromolecule (cSMM) was synthesized, characterized by FT-IR spectroscopy and blended into the casting solution of cellulose acetate (CA) to prepare surface modified UF membranes by phase inversion technique. With an increasing cSMM additive content from 1 to 4 wt%, pure water flux (PWF) and water content (WC) were increases whereas the hydraulic resistance decreases. Surface characteristic study reveals that the surface hydrophilicity increased in cSMM modified CA membranes. The pore size and surface porosity of the 4 wt% cSMM blend CA membranes increases to 41.26 Å and 0.015%, respectively. Similarly, the molecular weight cut-off (MWCO) of the membranes ranged from 20 to 45 kDa, depending on the various compositions of the prepared membranes. Lower flux decline rate (47.2%) and higher flux recovery ratio (FRR) (89.0%), exhibited by 4 wt% cSMM blend membranes demonstrated its fouling resistant characteristic compared to pristine CA membrane.     

Designing energy efficient commercial buildings—A systems framework

This paper provides a means for improving the effectiveness of energy related decision-making during the design phase of a building. A review of the literature and discussions with experts revealed that several approaches for an Integrated Design Process for energy efficient buildings exist. However, most of these approaches are relatively abstract and philosophical in nature, and do not prescribe procedures that enable energy efficient design.This paper attempts to address this gap by proposing a comprehensive design process titled the ‘Integrated Energy-Efficient Building Design Process’ (IEBDP). This process provides a framework based on systems theory that facilitates the integration of various facets of the energy-efficient alternatives selection process. In addition, the proposed framework seeks to integrate state-of-the-art analysis tools and methods, to aid designers in performing holistic building design. Analytical Hierarchy Process (AHP), a multi-attribute decision-making technique is used to resolve conflicts amongst diverging design goals.The proposed IEBDP framework was then used to design an office building, taken as a case study, in the composite climate of New Delhi, India. It was found that considerable energy savings could be achieved by following the IEBDP process. The benefits of this framework vis-a-vis traditional energy efficient design approaches were evaluated by comparing the design done through the IEBDP process with designs submitted by a group of practicing architects. The various designs were evaluated in terms of strategies adopted, the level of exploration as well as design integration, in order to validate the applicability and use of the IEBDP framework.     

Differential evolution variants to schedule flexible assembly lines

Scarce resources such as material, labor, and equipment are to be optimized to improve the performance and lower production costs in flexible assembly lines. These resources are usually allocated optimally through the generation of schedules. In this paper, variants of a differential evolution-based algorithm are employed to schedule flexible assembly lines (FAL). The performance of the assembly line is optimized based on two performance criteria, namely the weighted sum of Earliness/Tardiness penalties and the balance of the assembly line. Different variants of the Bi-level differential evolution (BiDE) algorithms are developed to study the effects of three FAL problems. The parameters of BiDE algorithm for FAL problems are fine-tuned. The performance of the BiDE algorithm is evaluated using the datasets and the Bi-level Genetic Algorithm (BiGA) available in the literature. The experimental results show that the proposed differential evolution-based algorithm outperforms BiGA in terms of mean best fitness.     

Object-oriented methodology for intersection simulation model under heterogeneous traffic conditions

In developing countries like India, the traffic on roads is highly heterogeneous in nature, with vehicles of widely varying static and dynamic characteristics. In this type of traffic, vehicles do not follow lane discipline and they move freely over the entire width of roadway based on availability of space. To study this type of complex traffic flow and associated vehicular interactions, simulation is considered as an effective tool. An object-oriented methodology (OOM) for heterogeneous traffic simulation is proposed in this paper with focus on mid-block and intersection flow modeling. The paper presents the basics and advanced features of object-oriented programming (OOP) in detail in the context of traffic flow. The sample C++ code is discussed in detail to demonstrate the implementation of OOP features, such as encapsulation, inheritance and polymorphism. The contribution of this research work is the development of software objects for various components such as vehicle, traffic, link and node. This software can be adopted for heterogeneous traffic simulation programs, in general.     

Particle size effect on the magnetic properties of NiO nanoparticles prepared by a precipitation method

Nickel oxide (NiO) nanoparticles of nominal size range 16 nm and 25 nm were obtained by controlling the calcination temperature. These particles were prepared by the precipitation method. Structural, optical and morphological characterizations were done by X-ray powder diffraction, UV-vis diffuse reflectance spectroscopy and scanning electron microscopy. Studies of magnetic measurements (up to 60 kOe) and temperature variations from 2 K to 300 K of the NiO nanoparticles were investigated. Particles of 16 nm exhibited a weak ferromagnetic component and hysteresis loop. There is a increase in coercivity H_c and the remanence M_r at 8 K accompanied by an exchange bias H_E. H_E monotonically tends to zero as the particles size varied from 16 nm to 25 nm. The hysteresis loop and the size dependent χ are interpreted with the uncompensated surface spins, whereas the transition at 30 K is suggested to be Néel temperature T_N of the spins in the core of the 16 nm particles. In addition, the increasing temperature cannot showed an approach to saturation in the magnetization curve, it indicates the possibility of an asperomagnetism and/or spin glass behavior of the NiO nanoparticles.     

Incorporation of pyridinic and graphitic N to Ni@CNTs: As a competent electrocatalyst for hydrogen evolution reaction

Cheap production of hydrogen (H₂) from eco-friendly routes is preeminent for solving future energy challenges. This study explores the hydrogen evolution reaction (HER) activity of nickel (Ni) nanoparticles and nitrogen doped carbon nanotubes (NiNCNTs), which are fabricated by a cheap and one-step pyrolysis method. The most active catalyst synthesized at 800°C exhibits an overpotential of 0.244 V to reach a current density of 10 mA cm⁻², Tafel slope of 93.3 mV dec⁻¹ and a satisfactory 10 hours stability. Low resistance and large ECSA value of the sample also favor the competent response for HER in alkaline media. The robust HER activity of the catalyst is as a result of the nickel nanoparticles which are the active spots of reaction; while the presence of well-developed nitrogen containing carbon nanotubes with large content of pyridinic and graphitic nitrogen may provide high-electron density and feasible routes for its transportation to deliver an outstanding HER performance.     

Improved sheep flock heredity algorithm and artificial bee colony algorithm for scheduling m-machine flow shops lot streaming with equal size sub-lot problems

The objective of this paper is to develop intelligent search heuristics to solve n-jobs, m-machines lot streaming problem in a flow shop with equal size sub-lots where the objective is to minimise makespan and total flow time independently. Improved sheep flock heredity algorithm (ISFHA) and artificial bee colony (ABC) algorithms are applied to the problem above mentioned. The performance of these algorithms is evaluated against the algorithms reported in the literature. The computational analysis shows the better performance of ISFHA and ABC algorithms.