Designing Liquid Crystal for Optoacoustic Detection

This research impacts the development of a cost-saving, on-chip device that can replace a wide range of costly, bulky sensors for commercial and defense applications. In particular, the goals of this work were to design and test a sensor that uses the optical properties of liquid crystal (LC) to detect acoustic waves. This began with developing a method to fine-tune the optical features of the liquid crystal. Statistical analysis of select experimental variables, or factors, lead to ideal settings of those variables when creating the sensor. A two-factor and three-factor experiment were separately conducted and analyzed as a preliminary demonstration of this system. The identification of dominant and ideal factor levels, including their interactions, enabled a statistically enhanced molecular design method of LC for use in many types of sensor applications. Detecting acoustic waves using the optical properties of a material, or optoacoustic detection, was chosen as the application to test the designed LC. Research continued with analytically calculating the interaction between the soundwaves and the optical and mechanical properties of the LC. Systematic comparisons between a commercially available acoustic sensor system and this theoretical LC optoacoustic detector are provided. Development concluded with a test which demonstrated that ordered, chiral nematic phase of LC can inherently improve an existing acoustic sensing device. Recommendations for further development are discussed

An evaluation of MAAP’s Train the Simulator Trainer and Assessor (IMO Model Course 6.10): trainees’ perspectives and reverberations

The study aims to analyze how the trainees evaluate the “Train the simulator trainer and assessor” (IMO Model Course 6.10) provided by the Maritime Academy of Asia and the Pacific (MAAP) for free in cooperation with the Maritime Industry Authority (MARINA) and the Commission on Higher Education (CHED). The training is regularly rendered as one of the extension services of MAAP. The study utilized the data from the evaluation form accomplished by the eight batches corresponding to 94 trainees in 2019. Results showed that the trainees regarded the training as “Excellent” in terms of the General Information. The trainees likewise rated the training as “Excellent” in terms of the Topics/Exercises. Statistics showed that there was no significant difference between the evaluation of the trainees on the training on IMO Model Course 6.10 when they are grouped according to batches both in General Information and Topics/Exercises

Defense-through-Deception Network Security Model: Securing University Campus Network from DOS/DDOS Attack

Denial of Service (DOS) and (DDOS) Distributed Denial of Service attacks have become a major security threat to university campus network security since most of the students and teachers prepare online services such as enrolment, grading system, library etc. Therefore, the issue of network security has become a priority to university campus network management. Using online services in university network can be easily compromised. However, traditional security mechanisms approach such as Defense-In-Depth (DID) Model is outdated in today’s complex network and DID Model has been used as a primary cybersecurity defense model in the university campus network today. However, university administration should realize that Defense-In-Depth (DID) are playing an increasingly limited role in DOS/DDoS protection and this paper brings this fact to light. This paper presents that the Defense-In-Depth (DID) is not capable of defending complex and volatile DOS/DDOS attacks effectively. The test results were presented in this study in order to support our claim. The researchers established a Defense-In-Depth (DID) Network model at the Central Luzon State University and penetrated the Network System using DOS/DDOS attack to simulate the real network scenario. This paper also presents the new approach Defense-through-Deception network security model that improves the traditional passive protection by applying deception techniques to them that give insights into the limitations posed by the Defense-In-Depth (DID) Model. Furthermore, this model is designed to prevent an attacker who has already entered the network from doing damage

Zig-Zag magnetic order and potential Kitaev interactions in the spin-1 honeycomb lattice KNiAsO4_4

Despite the exciting implications of the Kitaev spin-Hamiltonian, finding and confirming the quantum spin liquid state has proven incredibly difficult. Recently the applicability of the model has been expanded through the development of a microscopic description of a spin-1 Kitaev interaction. Here we explore a candidate spin-1 honeycomb system, KNiAsO$_4$ , which meets many of the proposed criteria to generate such an interaction. Bulk measurements reveal an antiferromagnetic transition at $\sim$ 19 K which is generally robust to applied magnetic fields. Neutron diffraction measurements show magnetic order with a $\textbf{k}=(\frac{3}{2},0,0)$ ordering vector which results in the well-known ``zig-zag" magnetic structure thought to be adjacent to the spin-liquid ground state. Field dependent diffraction shows that while the structure is robust, the field can tune the direction of the ordered moment. Inelastic neutron scattering experiments show a well defined gapped spin-wave spectrum with no evidence of the continuum expected for fractionalized excitations. Modeling of the spin waves shows that the extended Kitaev spin-Hamiltonians is generally necessary to model the spectra and reproduce the observed magnetic order. First principles calculations suggest that the substitution of Pd on the Ni sublattice may strengthen the Kitaev interactions while simultaneously weakening the exchange interactions thus pushing KNiAsO$_4$ closer to the spin-liquid ground state.Comment: 13 pages, 7 figure

Microscopic mechanisms of spin-dependent electric polarization in 3d oxides

We present a short critical overview of different microscopic models for nonrelativistic and relativistic magnetoelectric coupling including the so-called "spin current scenario", ab-initio calculations, and several recent microscopic approaches to a spin-dependent electric polarization in 3d oxides.Comment: 8 pages, 3 figure