Selective coupling of optical energy into the fundamental diffusion mode of a scattering medium

We demonstrate experimentally that optical wavefront shaping selectively couples light into the fundamental diffusion mode of a scattering medium. The total energy density inside a scattering medium of zinc oxide (ZnO) nanoparticles was probed by measuring the emitted fluorescent power of spheres that were randomly positioned inside the medium. The fluorescent power of an optimized incident wave front is observed to be enhanced compared to a non-optimized incident front. The observed enhancement increases with sample thickness. Based on diffusion theory, we derive a model wherein the distribution of energy density of wavefront-shaped light is described by the fundamental diffusion mode. The agreement between our model and the data is striking not in the least since there are no adjustable parameters. Enhanced total energy density is crucial to increase the efficiency of white LEDs, solar cells, and of random lasers, as well as to realize controlled illumination in biomedical optics.Comment: 5 pages, 5 figure

3D spatially-resolved optical energy density enhanced by wavefront shaping

We study the three-dimensional (3D) spatially-resolved distribution of the energy density of light in a 3D scattering medium upon the excitation of open transmission channels. The open transmission channels are excited by spatially shaping the incident optical wavefronts. To probe the local energy density, we excite isolated fluorescent nanospheres distributed inside the medium. From the spatial fluorescent intensity pattern we obtain the position of each nanosphere, while the total fluorescent intensity gauges the energy density. Our 3D spatially-resolved measurements reveal that the local energy density versus depth (z) is enhanced up to 26X at the back surface of the medium, while it strongly depends on the transverse (x; y) position. We successfully interpret our results with a newly developed 3D model that considers the time-reversed diffusion starting from a point source at the back surface. Our results are relevant for white LEDs, random lasers, solar cells, and biomedical optics

Morphology of F-region vertical E×B drifts in the African sector using ionosonde measurements

F-region vertical velocities are derived from the ground-based ionosonde data for Ibadan (7.4°N, 3.9°E; dip 6°S: an equatorial station in the African zone), to study the general characteristics of electrodynamics of equatorial ionosphere, such as their variation with season, solar cycle, and magnetic activity at different local time sectors. The results show profound seasonal and geomagnetic effects. Except for equinoctial period, there is an excellent consistency in the magnitudes (nearly 20 m/s) and patterns of upward daytime F-region drifts at low and high solar activity periods. Evening F-region exhibits strong motion with absolute mean value for quiet-time (15 m/s) greater than on disturbed-time (10 m/s). The average downward quiet midnight-early morning hours sector value is well below than 10 m/s. The evening reversal time is earliest and latest during solstitial periods. Prereversal peak is season dependent and varies strongly with magnetic activity. We show that prereversal peak, daytime, and nighttime maximum drifts saturate at particular values of F10.7 cm solar radio flux index, effects not noticed with corresponding sunspot number. Our observations confirm several previous results from other equatorial sites utilizing different experimental techniques

The Visual Typicality of Non-Alcoholic Beverage (NAB) Package Forms in Akure, Nigeria

This study identified the popularity of Non-Alcoholic Beverages (NAB) package forms in Akure for the purpose of exploring the possibility of creating visual code for easy product categorization and nomenclature in the non-alcoholic beverage product category. The research methodology involved collection, observation, and recording of the selected NAB through purposive sampling. A total of 218 product names of NABs were collected from the Akure Shopping Mall. By using Microsoft excel and SPSS 17 for analysis, the findings show that there is increase in multiple uses of NAB package forms. Keywords: NAB, Visual code, typicality, product identification, nomenclature, form, Package Desig

Can Lifestyle Factors of Diabetes Mellitus Patients Affect Their Fertility?

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Unified Sensing, Diagnosis and Active Self-Healing

The application of self-healing material in industrial systems has the potential to improve reliability and save cost. This is because faults do occur in systems, and for life critical or remote or difficult to access ones, current maintenance practices may be insufficient. When such systems are self-healed, the materials making up the systems regain some or all of its lost physical properties to keep the systems functioning. However, a majority of self-healing approaches are not yet at the level of industrial integration. These self-healing approaches are passive and do not guarantee a match between the damage and healing rate. A significant step in their advancement is the development of an integrated sensing, fault diagnosis and active self-healing system, which is the focus of this thesis. A mathematical model based on a previously experimented electromechanical self-healing process, whose healing mechanism combines piezoelectricity and electrolysis is developed. The model demonstrates the poor match between the damage and healing rate due to the ineffectiveness of the healing process to counteract the onset of damage, the dominant effect of uncertainties and disturbances on the healing process, the dependence of healing on the location of the healing mechanism relative to the fault location, etc. In addition, nonlinearities, such as the inherent dead-zone of the chosen healing mechanism affect the response of the healing process. The model also provides a benchmark for the work in this thesis. The model is then the foundation for the development of a novel active self-healing system. This is a closed loop system that takes advantage of sensing and adaptive sliding mode feedback control with the modelled healing mechanism to achieve a desired response. Importantly, it is shown in simulation that adaptive feedback control (sliding mode control) can minimize the effect of uncertainties, regulate the healing rate of a self-healing system to meet user or environmental demands, such as the damage rate, and compensate for the non-linear dead-zone associated with this healing mechanism. Finally, a novel fault diagnosis method that combines the beam curvature, proportional orthogonal decomposition, Hölder exponent and supervised regression is presented as a step to define the environmental demands. This essentially captures the effect of damage of a beam structure. It is combined with the active self-healing system, leading to a novel framework for an integrated sensing, fault diagnosis and closed loop active self-healing system. It is shown through simulation that the proposed active system can potentially estimate the damage rate, provide adequate actuation to match the healing rate with the estimated damage rate and provide real time insight into the healing dynamics

Growth of Pseudomonas aeruginosa LP5 on 2, 5-dicchlorobenzoate: Detection of aromatic ring hydroxylating dioxygenase (ARHDO) gene

Pseudomonas aeruginosa LP5 grew on 2, 5-dichlorobenzoate with doubling time (D) 6.64 d and mean growth rate (k) 0.104 d-1. The organism showed a prolonged lag period lasting 9 days followed by a sudden rise within 3 days (D= 1.1 d; k= 0.628 d-1) and death in less than 72 hours on 2, 6-dichlorobenzoate. Polymerase chain reaction (PCR) amplification of DNA of LP5 showed aromatic dihydroxylating (ARHDO) gene band with molecular weight corresponding to the targeted fragment (0.73 kb). The capability of LP5 on dichlorobenzoates and detection of dioxygenase genes is a validation of its versatility and potential for bioremediation

Appraising the Effects of Computer Aided Design (CAD) on the Creative Behaviour of Design Students in Tertiary Institutions in Nigeria: A Case Study of the Federal University of Technology Akure

As a result of the advancement of digital technologies intellectual discourse on the role of innovations in design and what value Computer Aided Design CAD brings into the equation has been on the increase This research sought to appraise the effects of CAD on the creative behaviour of students offering design related courses in tertiary institutions with a focus on the Federal University of Technology Akure FUTA Nigeria From the literatures reviewed Creative Behaviours Model CBM proposed by Musta amal Norman Hodgson was adopted and served as a framework for capturing the creative behaviour of the target population This model characterised creativity into seven sub categories namely novelty appropriateness motivation fluency flexibility sensitivity and insightfulness A survey method was employed for this study and data were collected using well-structured online questionnaires to elicit responses from both students and CAD instructors in concerned departments in FUTA The outcome of the study reveals the areas of application of CAD software and the level of engagement of students in CAD related courses It also shows the assessment of students performance in CAD related courses from the perspective of the students and their instructors The study concludes that CAD can enhance student s creative behaviour and more integration of CAD related courses into the curricula of tertiary institutions in Nigeria will lead to higher competency and global competitiveness rating of future professional designers and engineer