Design Of Circularly Polarized Rectenna With Harmonic Rejection Capabiltity At 2.45 Ghz For Microwave Energy Transfer

Nowadays, with the fast development in wireless devices, microwave energy transfer in which energy is transmitted from one point to another without wires, becomes more vital. There are many applications in which microwave energy transfer technology can be utilized such as smart healthcare, environmental monitoring, and home automation. Microwave energy transfer has the advantages of easy communication and lower cost compared to traditional transmission mediums. A rectifying antenna or rectenna which consists of receiving antenna, rectifier, matching network, and output DC filter, is an important element in microwave energy transfer. The antenna receives RF signals that are converted from alternative current (AC) into usable direct current (DC) by the rectifying circuit. Rectifying diodes have nonlinear behavior which generates harmonics and degrades RF-to-DC conversion efficiency of the rectenna. Harmonic rejection filter is used to suppress these harmonics. However, adding harmonic rejection filter increases the size and cost of the rectenna. Antennas with harmonic rejection is used to replace the harmonic rejection filter. However, the proposed antennas have a low gain which degrades rectenna conversion efficiency. To increase the amount of collected RF signals, circular polarization, dual-band and broadband operation are adopted but these techniques increase the size and design complexity. This thesis proposed a rectenna design with harmonics rejection and circular polarization at 2.45 GHz to enhance the RF-DC conversion efficiency. The harmonic rejection capability is achieved using triangular aperture coupling slot. The circular polarization property is achieved with a single feed line which reduces the size and design complexity. The aperture coupled antenna is simulated with an air gap to enhance the gain, using Computer Simulation Technology (CST). The voltage doubler rectifier is simulated with a fast switching HSMS286B Schottky diode, using Advance Design System (ADS). The fabrication process is carried out using a low-cost 4.4 permittivity FR-4 substrate. The antenna can reject harmonics up to 10 GHz with -50 dB return loss, 7 dB gain, 1.5 dB axial ratio and 40.8% axial ratio bandwidth. The doubler rectifier with radial stub filter can provide output DC voltage higher than 7 V. The measured RF-to-DC conversion efficiency of the integrated rectenna is 76.84%. at an input power of 20 dBm. The proposed rectenna has the advantages of harmonic rejection, circular polarization, high gain and low cost which make it a suitable candidate for microwave energy transfer

EFFECTIVE MICROORGANISMS (EM) DISPERSION SYSTEM FOR DILUTING POLLUTANT IN RIVER

Nowadays, effective microorganism technology is widely used in treating and improving water quality for its environmentally friendly properties. The quality of river water can be considered as one of the most important concern for official authorities worldwide. In Malaysia, the local government is tending to enhance the water quality of rivers in the county by utilizing effective microorganism technology. Determining the suitable amount of the EM to improve water quality is one of the barriers that need to overcome. This report discusses one of the proposed methods for solving the issue of distributing random amount of effective microorganism (EM) in river. Utilizing an automated control system is the focal objective of this writing to dilute pollutant in river. By using such technology, effective microorganism will be poured into the river in mud-ball form based on the need of it. In this paper, developing a prototype consists of well-designed control system to test and study the impact of EM dispensation in a tank of water will be explained in details

Contextualising Islam

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Depositional Environment, Geochemistry, and Diagenesis of Paleocene and Early Eocene Carbonates of Agdabia Trough, Libya

The study of the Paleocene and Early Eocene rocks of the Agdabia Trough, on the eastern edge of the Sirte basin of Libya, was undertaken to assess the depositional environment, the geochemistry, the succeeding diagenetic processes, and the resultant porosity of the sequence, and to investigate the causes of low permeability. The results indicate predominantly slope deposition. The investigated sequence has been divided into seven lithofacies. These start with lithoclast bearing mudstones which are interpreted as debris flow deposits, associated with hemipelgic muds deposited at the base of the slope. These are overlain locally by thin pelletal packstones which are followed by chalks. The sequence is capped by lithofacies with large nummulites and finally by lithofacies with small nummulites. In the northern part of the area dolomite dominates sometimes co-existing with diagenetic evaporites. The slope stretched more than 30Km from the Cyrenaica platform to the basin centre where relatively deep water sediments dominated. The early Eocene interval documents a dramatic change in deposition and transition to shallow water sediments, represented by nummulitic limestones. The sedimentary pattern in the Eocene was dominated by shallowing upward cycles in the nummulitic limestone. These are belived to be due to falls in sea level which caused progradation of shallow water nummulitic banks over deep water slope deposit. Many diagenetic alterations have been revealed. Diagenetic events began with dissolution and compaction, locally succeeded in the northern area by dolomitization. A second stage of dissolution followed by anhydrite deposition post dated the dolomitization. Equant calcite is the dominant cement and it is present mainly filling intraskeletal chambers of foraminifera. Dolomite dominates the Paleocene section in the northern part of the area. The geological, petrographical and geochemical evidence implies that the dolomitization process was accomplished by penetration of highly saline fluids derived from the Cyrenaica platform and took place under more than 1Km of burial. Cathodoluminescence petrography reveals four types of correctable luminance within the studied wells. These include bright matrix and cement, dull luminescence, non luminescence and finally dull matrix with two cement stages. The distribution of these types in the area implies that oxic water driven from the Cyrenaica platform which gradually changed to a more reduced state down slope. The lateral changes in the luminescence types are paralleled by similar changes up section which are interpreted as due to progressive subsidence or burial. Geochemical studies show moderate strontium (Sr) values, in the limestones rangeing between 322 to 1600ppm, while in the dolomite Sr is relatively low. Other trace elements , such as iron (Fe) and manganese (Mn) are generally low, while sodium values are quite high in the dolomite reaching 7000ppm. The isotope analyses carried out chiefly on the dolomites, show depletion in delta18O, with quite negative values ranging between -2.4 to -8.3‰ (PDB). The equilibrium relationship calculation between delta18O of the dolomite, the delta18O of the precipitating water and the temperature reveals that the temperature of the precipitating water lay between 50-80°C and that the water was enriched by +5‰ in delta18O with respect to the sea water. This implies that the water which was responsible for dolomitization was an evaporated sea water. The delta13C values of the dolomites range between 0.6 to 2.5‰ (PDB), reflecting formation in water in equilibrium with marine sediments. The Sulphur isotope (delta34S) results from the anhydrite average 21.37‰ (CDT). This figure is consistent with the range of delta34S isotopic values known for marine evaporites of Tertiary age. Fluid inclusions in the dolomites reveal an average recorded temperature of 105°C and salinity ranges between 162-210ppt NaCl equivalent. Inspection of porosity in thin-sections and sonic logs suggests that the large nummulite lithofacies which apparently has good porosity might serve as a good reservoir rock, but more detailed study is required. Porosity and permeability are enormously influenced by calcium sulphate precipitation which occluded some porespaces and narrowed porethroats, resulting in a reduction of the permeability in the area

Automatic Transformation of Natural to Unified Modeling Language: A Systematic Review

Context: Processing Software Requirement Specifications (SRS) manually takes a much longer time for requirement analysts in software engineering. Researchers have been working on making an automatic approach to ease this task. Most of the existing approaches require some intervention from an analyst or are challenging to use. Some automatic and semi-automatic approaches were developed based on heuristic rules or machine learning algorithms. However, there are various constraints to the existing approaches of UML generation, such as restriction on ambiguity, length or structure, anaphora, incompleteness, atomicity of input text, requirements of domain ontology, etc. Objective: This study aims to better understand the effectiveness of existing systems and provide a conceptual framework with further improvement guidelines. Method: We performed a systematic literature review (SLR). We conducted our study selection into two phases and selected 70 papers. We conducted quantitative and qualitative analyses by manually extracting information, cross-checking, and validating our findings. Result: We described the existing approaches and revealed the issues observed in these works. We identified and clustered both the limitations and benefits of selected articles. Conclusion: This research upholds the necessity of a common dataset and evaluation framework to extend the research consistently. It also describes the significance of natural language processing obstacles researchers face. In addition, it creates a path forward for future research

Real options modeling and valuation of price adjustment flexibility with an application to the leasing industry

Uncertainty poses not only threats but also opportunities. This study sought to build the scientific foundation for introducing a real options (ROs) methodology for price risk management to the leasing industry. A price risk management that allows for both coping with threats and taking advantage of opportunities. In the leasing industry, fixed rate long-term lease contracts help contract parties stabilize cash flows within volatile markets. The contract\u27s term, however, may be extended long enough that prevent capturing the opportunities of gaining greater profits or reducing expenses. Therefore, the flexibility that enables participants to take advantage of favorable market price is desirable. This discussion is dedicated to the study of three different forms of price adjustments flexibility: 1) single-sided price adjustment flexibility (SSPAF). 2) double-sided price adjustment flexibility (DSPAF) with the preemptive right to exercise. 3) DSPAF with the non-preemptive right to exercise. Each was designed to meet various participants flexibility requirements and budgets. An ROs methodology was developed to model, price, and optimize these flexibility clauses. The proposed approach was then tested in the example of Time Charter (TC) rate contracts from the maritime transport industry. Both the metric and the process for quantifying the benefit of the proposed flexibility clauses are provided. This work provides an alternative approach to the price risk management, which is accessible to all participants in the leasing industry. It is also the starting point in studying the multiple-party, multiple-exercisable price adjustment flexibility. Moreover, both the flexibility designs and the proposed ROs methodology for price risk management are applicable to not only other forms of lease contracts but also to other forms of contract relationships. --Abstract, page iii

Crafting emotional engagement and immersive experiences: Comprehensive scale development for and validation of hospitality marketing storytelling involvement

This study develops and validates a scale for gauging consumer involvement in storytelling (to create memorable and emotionally resonant experiences) in hospitality marketing through four phases: qualitative inquiry, construct definition, item refinement, and nomological validation. Validation involves 24 in-depth video interviews and consecutive online surveys. The hospitality marketing storytelling involvement scale, with four dimensions—contextual cues, emotional engagement, mental cognition, and immersive experience—comprising 14 items, precisely measures consumer involvement. The scale integrates narrative transportation theory and the elaboration likelihood model to enhance understanding of consumer engagement with fundamental human cognitive and emotional processes. The validated scale offers a valuable tool for marketers to precisely assess consumer involvement and strategically leverage storytelling to evoke emotions, foster brand loyalty, and judge campaign effectiveness. In diverse marketing contexts that elicit emotions, resonate with individuals, and foster immersive experiences, the scale demonstrates remarkable adaptability. Ultimately, it can help marketers craft compelling narratives, enhance brand perception, and strengthen consumer relationships, thereby contributing to emotional connections, optimizing strategies, and enhancing consumer engagement effectiveness