Determining the Antibacterial Efficacy of Ylang Ylang (Cananga ordorata) Plant Extract on Esherichia coli

Esherichia coli (E.coli) is a bacterium with high prevalence in the gastrointestinal tract of humans and animals. Discovered in 1885, E. coli is part of normal gut bacteria flora. However, some strains can be pathogenic and may also lead to serious infection. For instance, the pathogen E. coli O157:H7 produces a Shiga toxin, a toxin also produced by the bacterium Shigella dysenteriae, and can cause dysentery in humans. This pathogen is notorious for causing illness, hospitalizations, and deaths annually. The objective of our research is to determine the antibacterial effectiveness of the Ylang Ylang (Cananga odorata) and its essential oil extract on E. Coli. Ylang Ylang is a widespread plant on Saipan and has been a prevailing medicine used by locals. Medicinal properties that attribute the plant include its anti-depressant, hypotensive, and antiseptic related substances. We will utilize these properties by extracting the essential oils through steam distillation. Moreover, we hypothesize that due to its medicinal properties the Ylang Ylang plant will have a significant impact on E.coli. We expect the findings of our research to enable a better comprehension of local medicinal plants and their effect on distinct bacteri

The Point of Views of Indonesian Mufassir (M. Quraish Shihab and Hamka) on Polygamy and its Relevance to Legislation in Indonesia

Asr prayer is one of the obligatory prayers performed at specific times among the five daily prayers. However, in the literature of fiqh, there is a division of Salat Asar into fadīlah (preferred time), ikhtiyār (permissible time), and jawāz (allowable time). This is closely related to the virtue of performing the prayer in its early time, as mentioned in the sayings of the Prophet Muhammad, and the discouragement of delaying Asr prayer until its later time. It is essential to establish a precise time, specifying the exact hour and minute for faīlah, ikhtiyār, and jawāz in Asr prayer. There are two methods for determining the timing of fadīlah, ikhtiyār, and jawāz: firstly, through a fiqh approach, which involves observing the phenomena of the Sun’s movement, and secondly, through a scientific approach, using mathematical and astronomical calculations. Both the fiqh and scientific methods are integrated and mutually beneficial in the development of a formulation, providing ease in determining the timing of fadīlah, ikhtiyār, and jawāz in Salat Asar. Keywords: Asr prayer, Fadīlah, Ikhtiyār, Jawāz, fiqh, scienc

Guided wave propagation and scattering at composite delaminations

Composite structures, consisting of highly anisotropic layers of polymer matrix reinforced with high strength carbon fibers, are widely used for aerospace applications due to their low weight and high strength. However, impact during aircraft operation can lead to barely visible and difficult to detect damage. Depending on impact severity, delaminations can occur that reduce the structural integrity and load carrying capacity. Efficient structural health monitoring (SHM) of composite panels can be achieved using guided ultrasonic waves propagating along the structure. Guided ultrasonic wave propagation and scattering at circular delaminations was modelled using full three-dimensional (3D) Finite Element (FE) simulations in ABAQUS. Individual ply layers were modelled using unidirectional composite material properties to accurately capture the anisotropy effects. The guided ultrasonic wave propagation and scattered field at an artificial delamination was measured using a noncontact laser interferometer and quantified. Good agreement between experiments and Finite Element predictions was found and the energy trapping on top of a shallow delamination was verified. The influence of delamination shape and depth was investigated from a FE parameter study. The sensitivity of guided waves for the detection of delaminations due to barely visible impact damage (BVID) in composite panels has been verified

Guided wave propagation and scattering in anisotropic composite structures

Carbon fibre reinforced polymer (CFRP) laminates are widely used for aerospace applications as they reduce the weight of structures whilst maintaining mechanical strength. Composites have highly anisotropic material properties and high in-plane strength but poor interlaminar strength, making them vulnerable to barely visible impact damage (BVID) caused by low velocity impacts. Composite damage is multi-modal, consisting of fibre breakage, matrix cracking, and delaminations, with delaminations causing the most significant strength reduction. Guided ultrasonic waves, often generated using a sparse network of sensors bonded to a structure, provide a promising structural health monitoring (SHM) technique for composites. Guided waves propagate along a structure, with energy throughout the entire thickness, making them ideal for rapid, long-range inspection of large areas. In anisotropic materials wave energy is focused along the high stiffness (fibre) directions, resulting in higher amplitude and wave speed in these directions. Waves launched away from the fibre direction are steered towards the fibres. These anisotropic effects could lead to inaccuracies in damage localization if not accounted for. Propagation of the fundamental, flexural (A0) guided wave mode was investigated in an undamaged unidirectional CFRP panel. Anisotropic effects including the directionality of wave velocities, skew angles, and beam spreading were quantified through both finite element simulations and experiments, achieving good agreement with predictions obtained from dispersion curves. Scattering of the A0 mode at an artificial delamination was studied for a quasiisotropic CFRP plate layup. Wave-trapping on top of the delamination, and strong forward scattering at the delamination exit was found. Significantly different scattering behaviour was observed to that of a magnet target, often used to develop SHM systems. Scattering around both damage targets was found to be directionally dependent, with higher amplitudes in the fibre directions of the outermost laminae. Implications for the SHM of composites were discussed

Effect of material anisotropy on guided wave propagation and scattering in CFRP laminates

Carbon fiber laminates, consisting of highly anisotropic fiber-matrix ply-layers, are widely used in aerospace applications due to their good strength to weight ratio. However, poor interlaminar strength makes them prone to barely visible impact damage (BVID), significantly reducing the load bearing capacity of aircraft components. Guided ultrasonic waves have been widely used for structural health monitoring (SHM) of composite structures. Guided wave propagation and scattering at circular delaminations in a quasi-isotropic laminate was modelled using full three-dimensional (3D) Finite Element (FE) simulations in ABAQUS. Non-contact laser measurements were performed to obtain the scattered wavefield at a film insert delamination. The influence of ply layer anisotropy and incident wave direction were investigated both numerically and experimentally. Scattering directivity patterns were calculated using a baseline subtraction method and 2D scattering matrices were obtained for all incident wave directions. Circular magnets were used as a scattering target and numerical and measured scattering patterns were compared with those of the insert delamination. Strong directional dependency was observed for incident and scattered waves around both delamination and magnets, indicating energy focusing along the outer ply layers of the laminate. For the delamination a strong forward wave was observed, with low amplitude in other directions, whereas the magnet blocked forward transmission of the wave, demonstrating distinct scattering behavior. The anisotropic effects and different scattering patterns should be considered for guided wave sparse array SHM to ensure the robustness of imaging algorithms

Guided wave propagation and skew effects in anisotropic carbon fiber reinforced laminates

Guided ultrasonic waves provide a promising structural health monitoring (SHM) solution for composite structures as they are able to propagate relatively long distances with low attenuation. However, the material anisotropy results in directionally dependent phase and group velocities, in addition to energy focusing, wave skewing, and beam spreading phenomena. These effects could lead to inaccurate damage localization if not accounted for. In this contribution, the guided wave propagation behavior (A0 mode) for a highly anisotropic, unidirectional carbon fiber reinforced polymer laminate is systematically investigated through both finite element analysis and non-contact laser measurements and compared to theoretical predictions. The directional dependency of phase and group velocity measured for a point and line source shows good agreement with theoretical predictions, once a correction for wave skew effects is applied. Wave skew angles were evaluated from the experimental and numerical wave propagation in multiple directions and matched theoretical predictions based on the phase slowness curve. Significant guided wave beam spreading from a line source was observed and quantified from both experiments and simulations and compared with theoretical predictions using the anisotropy factor. The impact of anisotropic guided wave propagation behavior on SHM is discussed

Guided wave scattering analysis around a circular delamination in a quasi-isotropic fiber-composite laminate

Carbon fiber reinforced composites are widely used in the aerospace industry, but barely visible impact damage can lead to delamination and compromise the structural integrity. The scattering of the fundamental anti-symmetric guided wave mode (A0 Lamb mode) at an artificial circular delamination in a quasi-isotropic laminate was investigated experimentally. A 5 cycle Hanning windowed wave pulse was used as the excitation signal for the experiments. Fast Fourier Transform was employed to identify the guided wave amplitude of the scattered field along various directions. The experimental wavefield was captured using a laser Doppler vibrometer. Experimental results are presented for the scattering pattern and scattering amplitude as a function of distance from the damage. The results of this study can help to improve delamination detection techniques using guided waves and to gain physical insights into the scattering of guided waves at a delamination

Anisotropy influence on guided wave scattering for composite structure monitoring

Composite structures are widely used for aerospace applications but are prone to barely visible impact damage from low velocity impacts. Guided wave measurements using sparse arrays of distributed sensors provide an important structural health monitoring (SHM) tool for detecting and localizing impact damage in composites. However, the anisotropy of composites needs to be considered as it can affect guided wave propagation and scattering, impacting imaging performance. Improved defect characterization can be achieved by considering the scattering characteristics for the signal processing. Scattering around two different damage types for multiple incident wave directions in a quasi-isotropic carbon fiber reinforced polymer (CFRP) panel were investigated. Full 3D Finite Element (FE) simulations were compared to the measured scattered guided wave field at an artificial insert delamination. Permanent magnets mounted on an undamaged region of the plate were used as scattering targets and both numerical and experimental scattering patterns were compared to the delamination results. Strong directional dependency was observed for both damage types, with energy focusing along the fiber directions of the outer ply layers. For the delamination, mostly forward scattering is observed for all incident wave directions, whereas the magnet blocked forward wave transmission and scattered wave energy in all directions. 2D scattering matrices were calculated, demonstrating distinct scattering behavior for each damage type. Implications of anisotropy and angular scattering on SHM guided wave sparse array imaging are discussed

Guided Wave Energy Focusing and Steering in Composite Laminates

Lightweight, carbon fiber reinforced composites are often selected for aerospace components but are prone to barely visible impact damage, caused by low velocity impacts, during service. Guided-wave-based structural health monitoring (SHM) techniques can efficiently detect impact damage impact in composite structures. However, wave propagation is influenced by material anisotropy resulting in a number of effects. The phase and group velocity of propagating wave modes depend on the wave launching direction, with increased wave speeds in the high stiffness (fiber) directions. Wave energy tends to be focused along the fiber directions, resulting in beam steering or skewing away from the initial wave launching direction. These anisotropic effects, if unaccounted for, could lead to inaccurate localization of damage, and potential regions of the structure where guided waves cannot propagate with sufficient amplitude, reducing damage sensitivity. Wave propagation in an undamaged unidirectional carbon fiber reinforced polymer (CFRP) panel was investigated for the A0 mode for multiple wave launching directions. Finite Element (FE) modelling was carried out using homogenized anisotropic material properties to investigate the directional dependency of velocity. Point and line sources were modelled to investigate the influence of the excitation source on the guided wave evaluation and signal processing. Wave skewing behavior was visualized for the line source, and wave skew angles and beam spread angles were calculated for a range of propagation angles. Experimental non-contact guided wave measurements were obtained using a laser vibrometer. A PZT strip transducer was developed in order to measure wave skew angles. Experimental and numerical velocities and skew angles were compared with theoretical predictions and good agreement was observed