Similitude augmentation in sub-scale flight test model design: An MDAO based similarity maximization approach

By 2050, the aviation industry is expected to grow by 250-300% of its current air traffic. If left unchecked, the corresponding increase in atmospheric and noise pollution will have a catastrophic impact on the environment. Thus, improvements in aircraft design are urgently needed for a sustainable growth of the aviation industry. The...

Sub-scale flight test model design: Developments, challenges and opportunities

Growing interest in unconventional aircraft designs coupled with miniaturization of electronics and advancements in manufacturing techniques have revived the interest in the use of Sub-scale Flight Testing (SFT) to study the flight behaviour of full-scale aircraft in the early stages of design process by means of free-flying sub-scale models....

Photogeneration Quantum Yield and Character of Free Charges and Excitons in PbSe Nanorods

Lead selenide (PbSe) nanorods are of interest for applications in infrared LEDs, lasers, and photovoltaics due to the possibility of tuning their band gap from the far- to the near-infrared by decreasing their radius. We study the photogeneration quantum yield and properties of free charges and excitons in PbSe nanorods using a combination of...

The nature of photoexcitations and carrier multiplication in low-dimensional semiconductors

The aim of this thesis is to study the nature of photoexcitations and carrier multiplication in low-dimensional semiconductors using ultrafast spectroscopy techniques. Ongoing from a macroscopic scale to a nanoscale, the electronic and<br/>optical properties of a material become size dependent, and differ significantly from their bulk...

Explaining observed stability of excitons in highly excited CdSe nanoplatelets

Two-dimensional electron-hole gases in colloidal semiconductors have a wide variety of applications. Therefore, a proper physical understanding of these materials is of great importance. In this paper we present a detailed theoretical analysis of the recent experimental results by Tomar et al. [J. Phys. Chem. C 123, 9640 (2019)1932-744710...

Degree of similitude estimation for sub-scale flight testing

Sub-scaled Physical Models (SPM) are often employed in wind-tunnel tests or in free-flight tests (physical tests) to predict flight behavior of aircraft Full-scale Design (FD). However, a quality prediction of both the static and dynamic behavior is to date an open challenge. In this research, a methodology for designing SPMs is proposed for...

Room-Temperature Electron Transport in Self-Assembled Sheets of PbSe Nanocrystals with a Honeycomb Nanogeometry

It has been shown recently that atomically coherent superstructures of a nanocrystal monolayer in thickness can be prepared by self-assembly of monodisperse PbSe nanocrystals, followed by oriented attachment. Superstructures with a honeycomb nanogeometry are of special interest, as theory has shown that they are regular 2-D semiconductors,...

Charge Carrier Cooling Bottleneck Opens Up Nonexcitonic Gain Mechanisms in Colloidal CdSe Quantum Wells

Ultrathin two-dimensional (2D) materials have received much attention in the past years for a wide variety of photonic applications because of their pronounced room-temperature excitonic features, leading to unique properties in terms of light-matter interaction. However, only a few studies focus on light amplification and the complex...

Assessment of Sub-scale Designs for Scaled Flight Testing

Sub-scale Flight Testing (SFT) is potentially useful in predicting aircraft flight behaviour, especially in the case of unconventional designs for which legacy information is unavailable and wind tunnel tests are unable to predict aircraft dynamics. A necessary condition for SFT is the design of properly scaled models. However, even in case of...

Aerodynamic investigation of an over-the-wing propeller for distributed propulsion

This paper addresses the aerodynamic performance and numerical modeling of over-the-wing propellers. Installing the propeller above a wing has the potential to increase wing lift-to-drag ratio, high-lift capabilities, and to reduce flyover noise. However, the prediction of its performance is difficult, since research on the aerodynamic...

Efficient Steplike Carrier Multiplication in Percolative Networks of Epitaxially Connected PbSe Nanocrystals

Carrier multiplication (CM) is a process in which a single photon excites two or more electrons. CM is of interest to enhance the efficiency of a solar cell. Until now, CM in thin films and solar cells of semiconductor nanocrystals (NCs) has been found at photon energies well above the minimum required energy of twice the band gap. The high...

Ultrafast charge cooling and carrier multiplication in semiconductor nanocrystals and superlattices

We studied charge carrier photogeneration, cooling, carrier multiplication (CM) and charge mobility and decay in: a) isolated PbSe nanocrystals in solution, b) films of PbSe nanocrystals coupled by organic ligands, and c) 2D percolative networks of epitaxially connected PbSe nanocrystals. The studies were performed using ultrafast pump-probe...

Photogeneration and Mobility of Charge Carriers in Atomically Thin Colloidal InSe Nanosheets Probed by Ultrafast Terahertz Spectroscopy

The implementation of next generation ultrathin electronics by applying highly promising dimensionality-dependent physical properties of two-dimensional (2D) semiconductors is ever increasing. In this context, the van der Waals layered semiconductor InSe has proven its potential as photodetecting material with high charge carrier mobility. We...

Low Drift, Wireless Temperature Sensor for Harsh Industrial Applications

In this thesis, a stand-alone, battery powered, wireless temperature sensor that can be used for diagnostic purposes in harsh industrial environments, including magnetic interferences and very low pressure (vacuum), is presented. Being easily mountable and removable during machine stoppage, this autonomous temperature sensor can be used at any...

High charge mobility in two-dimensional percolative networks of PbSe quantum dots connected by atomic bonds

Two-dimensional networks of quantum dots connected by atomic bonds have an electronic structure that is distinct from that of arrays of quantum dots coupled by ligand molecules. We prepared atomically coherent two-dimensional percolative networks of PbSe quantum dots connected via atomic bonds. Here, we show that photoexcitation leads to...