Knowledge,attitude, and behavior of students regarding 'mad cow disease'

The aim of the current study is to assess the knowledge, attitude and behavior of students enrolled at the American University of Beirut (AUB) in Lebanon, towards mad cow disease (MCD). Three hundred and fifty-six students (199 males and 157 females), ranging in age between 17 and 25 years were randomly selected from various majors and were asked to fill out a self-administered questionnaire. It was found that 99.7% of students had heard about MCD and 85.8% knew that the cow is the host for bovine spongiform encephalopathy (BSE). Seventy five percent reported that animals contract the disease through the consumption of meat and bone meal. Thirty-seven percent wrongly believed that MCD cases were reported in Lebanon and 89% were not satisfied with the measures undertaken by the Lebanese government to curb the disease. Eighty four percent were concerned about the disease and 72% stated having modified their eating habits accordingly. Moreover, students majoring in biology and other health-related majors knew significantly more about MCD compared with students majoring in non-health related majors. A surprising finding was that females were more likely to modify their eating habits than males. Hence, this study provides an insight into the knowledge, attitude, and behavior of AUB students towards MCD. A limitation of this study is that our sample is not representative of all university students in Lebanon. Future surveys should also target students enrolled in other universities in the country.     

Closed Loop Predictive Optimal Control Algorithm Using ARMA Models

A predictive optimal control algorithm based on auto-regressive moving average (ARMA) models has been developed. Being a closed loop algorithm, it can be used in the control of structures against any source of random excitation without any special arrangement for measuring the excitation. The algorithm combines two mathematical models: (1) An ARMA model representing the environment and the structure as a single system subjected to the unknown random excitation; and (2) a single-degree-of-freedom system, which represents the structure subjected to a known history of control force only. Unlike some ARMA based control algorithms, which are only for seismic excitations, the proposed algorithm permits the control system to be operational under any type of dynamic load. This results in a large reduction in the standby time of the control system and increases its reliability. In comparison with these algorithms, the proposed algorithm requires less measurements and sensors. The algorithm has the option for reducing or avoiding time delay.     

Unveiling the role of carbon defects in the exceptional narrowing of m-ZrO2 wide-bandgap for enhanced photoelectrochemical water splitting

The development of efficient photoelectrodes via defect engineering of wide-band gap metal oxides has been the prime focus for many years. Specifically, the effect of carbon defects in wide-band gap metal oxides on their performance in photoelectrochemical (PEC) applications raised numerous controversies and still elusive. Herein, the effect of various carbon defects in m-ZrO₂ was investigated using the density functional theory to probe the thermodynamic, electronic, and optical properties of the defective structures against pristine m-ZrO₂. The defect formation energies revealed that elevating the temperature promotes and facilitates the formation of carbon defects. Moreover, the binding energies confirmed the stability of all studied complex carbon defects. Furthermore, the band edge positions against the redox potentials of water species revealed that all the studied defective structures can serve as photoanodes for water splitting. Additionally, C_O3c (carbon atom substituted O_3c site) was the only defective structure that exhibited slight straddling of the redox potentials of water. Importantly, all investigated defective structures enhanced light absorption with different optical activities. It is worth mentioning that our results showed exceptional reduction in the bandgap energy compared to those reported experimentally for ZrO₂-based materials. Finally, C_O3cV_O3c (carbon atom substituted O_3c associated with O_3c vacancy) defective m-ZrO₂ enjoyed lowest sub-bandgap (1.9 eV), low defect formation energy, low exciton binding energy, high mobility of charge carriers, fast charge transfer, and low recombination rate. Concurrently, its optical properties were exceptional in terms of high absorption, low reflectivity and improved static dielectric constant. Hence, the study recommends C_O3cV_O3c defective m-ZrO₂ as the leading candidate to serve as a photoanode for PEC applications.     

Structural engineering of Ti-Mn bimetallic phosphide nanotubes for efficient photoelectrochemical water splitting

Designing next-generation advanced electrode materials by engineering their structural and compositional features can provide a feasible strategy to enhance the electrochemical performance of energy conversion devices. In this study, the rational pathway to design and fabricate nanotube arrays of titanium manganese phosphide via etching of titanium-manganese alloy followed by plasma phosphidation in PH₃ environment is presented and discussed. The structural and elemental analyses of the air-annealed electrodes before plasma treatment confirmed the presence of different binary oxides; TiO₂, MnO, and Mn₂O₃. However, the XPS fitting showed the presence of Ti³⁺ and higher ratio of MnO when annealed in hydrogen atmosphere. The presence of composite oxides resulted in a band gap reduction, which increased the light harvesting capability of the material. This synergetic effect resulted also in a shift in the open-circuit voltage (V_OC) and almost 10-fold increase in the photocurrent density compared to the performance of the nanotubes annealed in air. Mott-Schottky analysis showed a four-orders of magnitude enhancement in the carrier density for the electrodes annealed in Hydrogen and treated in PH₃-plasma compared to those annealed in O₂ or air, ascribed to the creation of Ti³⁺ defects and phosphidation. Our study thus paves the way to a new approach for creating high-performance hybrid electrodes for PEC water splitting.     

Magnetic and Electronic Properties of Point Defects in ZrO2

Using the Korringa–Kohn–Rostoker Coherent Potential Approximation (KKR-CPA) method in connection with the Generalized Gradient Approximation (GGA), we study the magnetic and electronic properties of different point defects in cubic ZrO₂. In particular, we discuss the zirconium interstitial (Zr_i), zirconium antisite (Zr_O), zirconium vacancy (V_Zr), oxygen interstitial (O_i), oxygen antisite (O_Zr), and oxygen vacancy (V_O) defects. It has been shown that oxygen vacancy and zirconium interstitial (V_O, Zr_i) are n-type, while the other point defects are p-type. The magnetic moments are observed only in the oxygen interstitial and antisite (O_i, O_Zr) cases. The corresponding ferromagnetic states are more stable than the spin–glass states. It has been found that the mechanism responsible of such stabilities is the double exchange. Based on Mean Field Approximation (MFA), the Curie temperature (T _C ) is estimated. Moreover, it has been found that the O_i and O_Zr defects provide half-metallic properties being the responsible for ferromagnetism.     

Nano rods for coloured glasses obtained by hybrid sol-gel coating

Many new materials are now allowing new properties thanks to nanotechnology because this domain of physics gives possibilities to optimize targeted properties even if these materials react in very various influential parameters. Architectural, automotive, bone pathologies, environment, display applications are some concerned domains. The sol-gel process is a method allowing the realisation of coats at ambiant temperature, thus it is possible to realize Liquid Crystal Display (LCD), water-repellent coatings on privacy glass, antireflective coatings, hydrophobic or hydrophilic surfaces, bone tissue regeneration. In this study, the purpose is to show the thermal influence on a covered glass with a complex hybrid sol-gel solution. This coated glass is going to change color from red to orange under the heat influence. This color change effect comes from the evolution of various compounds organizations then/or from their loss during the degassing sequence. We show in spite of the complexity of the process that the responsible is mainly the organic dye. Thus the structure of the heated glass at 250 degrees C looks radically different than the heated one at 350 degrees C. SEM measurement allows to identify the surface compositions and to determine the elementary composition along the sample's cross section. TGA is used to justify a mass loss when samples are annealed. UV/Visible measurement is realized by two methods: in-line transmission to evaluate luminous flux and thus give colorimetric dot in the normalized CIE diagram and diffuse transmission to observe the size influence of the pigments. Infrared Reflectivity allows to evaluate the influence of species on the structure and to better target the nature of the lost compounds during annealing. TEM measurement proves that the obtained iron particles are nano rods for both samples.     

Fine-structure calculations of energy levels,oscillator strengths,and transition probabilities for sulfur-like iron,Fe XI

Energy levels, oscillator strengths, and transition probabilities for transitions among the 14 LS states belonging to configurations of sulfur-like iron, Fe XI, have been calculated. These states are represented by configuration interaction wavefunctions and have configurations 3s²3p⁴, 3s3p⁵, 3s²3p³3d, 3s²3p³4s, 3s²3p³4p, and 3s²3p³4d, which give rise to 123 fine-structure energy levels. Extensive configuration interaction calculations using the CIV3 code have been performed. To assess the importance of relativistic effects, the intermediate coupling scheme by means of the Breit–Pauli Hamiltonian terms, such as the one-body mass correction and Darwin term, and spin–orbit, spin–other-orbit, and spin–spin corrections, are incorporated within the code. These incorporations adjusted the energy levels, therefore the calculated values are close to the available experimental data. Comparisons between the present calculated energy levels as well as oscillator strengths and both experimental and theoretical data have been performed. Our results show good agreement with earlier works, and they might be useful in thermonuclear fusion research and astrophysical applications.     

A Simple Control Scheme for the High Performance Z-Source Inverter

In the past decade, the Z-source inverter (ZSI) is successfully developed for many applications. This paper proposes a simple integrated control scheme for the high performance ZSI. A proportional-integral PI controller is used to regulate the voltage of the Z-network capacitor. Moreover, the peak value of the DC-link voltage is controlled by limiting the shoot-through duty ratio. Furthermore, the instantaneous voltage control technique is utilized to retain the sinusoidal shape of the output voltage. A feed-forward signal of the AC voltage is employed to smooth the output voltage. To generate the PWM signals for the ZSI switches, the simple boost control method is utilized which coordinates the operation of different controllers. Extensive digital simulations are conducted to evaluate the dynamic behavior of the proposed control scheme. Moreover, an experimental setup is built to verify the performance of the proposed control scheme for the high performance ZSI.