An Analysis of Harmonic Airloads Acting on Helicopter Rotor Blades

Rotary wing aircrafts in any flight conditions suffer from excessive vibration which makes the passengers feel uncomfortable and causes fatigue failure in the structure. The main sources of vibration are the rotor harmonic airloads which originate primarily from the rapid variation of flow around the blade due to the vortex wake. In this thesis, a mathematical model is developed for rotor blades to compute the harmonic airloads at rotor blades for two flight conditions vertical takeoff and landing, and forward flight. The sectional lift, drag, and pitching moment are computed at a radial blade station for both flight conditions. The lift at a particular radial station is computed considering trailing and shed vortices and summing over each blade. The results for airloads are obtained after considering zeroth, first, and second harmonics. The calculated results for airloads are compared to the experimental flight-test data

The Impact of an Immunization Training Certificate Program on the Perceived Knowledge, Skills and Attitudes of Pharmacy Students Toward Pharmacy-Based Immunizations

Objective: To assess the impact of a national immunization training certificate program on the perceived knowledge, skills and attitudes of pharmacy students toward pharmacy-based immunizations. Methods: The study design utilized a pre- and post- survey administered to pharmacy students before and after the American Pharmacists Association’s (APhA) Pharmacy-Based Immunization Delivery program. The primary outcome explored was a change in the perceived knowledge, skills, and attitudes of the pharmacy students. A five-point Likert scale (i.e. strongly agree = 5, strongly disagree = 1) was used for measuring the main outcomes, which was summated by adding the individual item scores in each section to form a composite score for each outcome. Results: The certificate training program resulted in a significant improvement in knowledge (38.5% increase in score, p\u3c0.001) and skills (34.5% increase in score, p\u3c0.001), but not attitudes (1% increase in score, p=0.210). Conclusions: The national immunization training certificate program had a positive impact on the perceived knowledge and skills of pharmacy students. However, no change was observed regarding students’ perceived attitudes toward pharmacy-based immunizations

First Observation of an Acetate Switch in a Methanogenic Autotroph (Methanococcus maripaludis S2).

The transition from acetate production by a microorganism in its early growth phase to acetate re-uptake in its late growth phase has been termed acetate switch. It has been observed in several heterotrophic prokaryotes, but not in an autotroph. Furthermore, all reports hitherto have involved the tricarboxylic acid cycle. This study reports the first observation of acetate switch in a methanogenic autotroph Methanococcus maripaludis S2, which uses the Wolfe cycle for its anaerobic respiration. When grown in minimal medium with carbon dioxide as the sole carbon source, and either ammonium or dinitrogen as the sole nitrogen source, M. maripaludis S2 dissimilated acetate in the early growth phase and assimilated it back in the late growth phase. The acetate switch was more pronounced in the dinitrogen-grown cultures. We postulate that the acetate dissimilation in M. maripaludis S2 may serve as a metabolic outlet for the carbon overflow in the early growth phase, and the assimilation in the late growth phase may be due to the scarcity of the carbon source. Based on the primary and secondary protein structures, we propose that MMP0253 may function as the adenosine diphosphate (ADP)-forming acetyl-CoA synthetase to catalyse acetate formation from acetyl-CoA. To verify this, we produced MMP0253 via the ligation-independent cloning technique in Escherichia coli strain Rosetta (DE3) using pNIC28-Bsa4 as the vector. The recombinant protein showed catalytic activity, when added into a mixture of acetyl-CoA, ADP, and inorganic phosphate (Pi). The concentration profile of acetate, together with the enzymatic activity of MMP0253, shows that M. maripaludis S2 can produce acetate and exhibit an acetate switch

Charging infrastructure for commercial electric vehicles: Challenges and future works

The journey towards transportation electrification started with small electric vehicles (i.e., electric cars), which have enjoyed an increasing level of global interest in recent years. Electrification of commercial vehicles (e.g., trucks) seems to be a natural progression of this journey, and many commercial vehicle manufacturers have shifted their focus on medium- and heavy-duty vehicle electrification over the last few years. In this paper, we present a comprehensive review and analysis of the existing works presented in the literature on commercial vehicle charging. The paper starts with a brief discussion on the significance of commercial vehicle electrification, especially heavy- and medium-duty vehicles. The paper then reviews two major charging strategies for commercial vehicles, namely the return-to-base model and the on route charging model. Research challenges related to the return-to-base model are then analysed in detail. Next, different methods to charge commercial vehicles on route during their driving cycles are summarized. The paper then analyzes the challenging issues related to charging commercial vehicles at public charging stations. Future works relevant to these challenges are highlighted. Finally, the possibility of accommodating vehicle to grid technology for commercial vehicles is discussed

Defence and adaptation mechanisms of the intestinal epithelium upon infection

The intestinal epithelium is a monolayer of polarized columnar cells that act as a border between the host and its environment and are the first line of defence against the luminal microbes. In addition to providing a physical barrier, the epithelium possesses a multitude of active mechanisms to fight invading pathogens and regulate the composition and spatial distribution of commensals. The different epithelial cell types have unique functions in this context, and crosstalk with the immune system further modulates their intricate antimicrobial responses. The epithelium is organized into clonal crypt units with a high cellular turnover that is driven by stem cells located at the base. There is increasing evidence that this anatomical organization, the stem cell turnover, and the lineage determination processes are essential for barrier maintenance. These processes can be modulated by microbes directly or by the immune responses to enteric pathogens, resulting in a rapid and efficient adaptation of the epithelium to environmental perturbations, injuries, and infections. Here we discuss the complex host-microbial interactions that shape the mucosa and how the epithelium maintains and re-establishes homeostasis after infection

Green and secure computation offloading for cache-enabled IoT networks

The ever-increasing number of diverse and computation-intensive Internet of things (IoT) applications is bringing phenomenal growth in global Internet traffic. Mobile devices with limited resource capacity (i.e., computation and storage resources) and battery lifetime are experiencing technical challenges to satisfy the task requirements. Mobile edge computing (MEC) integrated with IoT applications offloads computation-intensive tasks to the MEC servers at the network edge. This technique shows remarkable potential in reducing energy consumption and delay. Furthermore, caching popular task input data at the edge servers reduces duplicate content transmission, which eventually saves associated energy and time. However, the offloaded tasks are exposed to multiple users and vulnerable to malicious attacks and eavesdropping. Therefore, the assignment of security services to the offloaded tasks is a major requirement to ensure confidentiality and privacy. In this article, we propose a green and secure MEC technique combining caching, cooperative task offloading, and security service assignment for IoT networks. The study not only investigates the synergy between energy and security issues, but also offloads IoT tasks to the edge servers without violating delay requirements. A resource-constrained optimization model is formulated, which minimizes the overall cost combining energy consumption and probable security-breach cost. We also develop a two-stage heuristic algorithm and find an acceptable solution in polynomial time. Simulation results prove that the proposed technique achieves notable improvement over other existing strategies

The Effects of Deregulation on the Performance of Financial Institutions: The Case of Spanish Savings Banks

This paper examines the impact of regulatory reform on the performance of Spanish savings banks. To this end it uses panel data for the period 1986-1995 and a flexible variable profit function that incorporates time-varying technical efficiency. The focus is whether increased competition brought on by deregulation affected performance of banks over time. Bank performance, measured by the percentage change in profitability, ceteris paribus, is decomposed into technical change and change in technical efficiency both of which are defined in terms of the profit function. We also examine output technical efficiency, which is defined in terms of the production possibility frontier. Several alternative models with different specifications of technical efficiency are used to check robustness of the results. Empirical results show declining levels of output technical efficiency along with a significantly high rate of technical progress. In spite of declining technical efficiency during this period, we find evidence of an increasing trend in productivity growth