Head Injury Analysis of Vehicle Occupant in Frontal Crash Simulation: Case Study of ITB's Formula SAE Race Car

In the present study, frontal crash simulations were conducted to determine the effect of various car speeds against the Head Injury Criterion (HIC), a measure of the likelihood of head injury arising from impact. The frontal impact safety of ITB's formula SAE race car designed by students was evaluated as a case study. LS-DYNA®, an explicit finite element code for non-linear dynamic analysis was utilized in the analysis. To analyze head injury, a two-step simulation was conducted. In the first step, a full-frontal barrier test was simulated without incorporating a dummy inside the car. The output was the deceleration data of the car, which was used as input in the second step, a sled test simulation. In the sled test, only the cockpit and dummy were modeled. The effect of deceleration to the head of the dummy was then evaluated. The results show that HIC values at an impact speed of 7 m/s (25 km/h) to 11 m/s (40 km/h) were below the safe limit and still in the safe zone. However, the HIC values will exceed the safe limit when the speed of impact is the same as or greater than 12 m/s (43 km/h)

A new displacement-based approach to calculate stress intensity factors with the boundary element method

The analysis of cracked brittle mechanical components considering linear elastic fracture mechanics is usually reduced to the evaluation of stress intensity factors (SIFs). The SIF calculation can be carried out experimentally, theoretically or numerically. Each methodology has its own advantages but the use of numerical methods has be-come very popular. Several schemes for numerical SIF calculations have been developed, the J-integral method being one of the most widely used because of its energy-like formulation. Additionally, some variations of the J-integral method, such as displacement-based methods, are also becoming popular due to their simplicity. In this work, a simple displacement-based scheme is proposed to calculate SIFs, and its performance is compared with contour integrals. These schemes are all implemented with the Boundary Element Method (BEM) in order to exploit its advantages in crack growth modelling. Some simple examples are solved with the BEM and the calculated SIF values are compared against available solutions, showing good agreement between the different schemes

Three-dimensional surface reconstruction of aircraft component using digital photogrammetry

In this paper, the application of photogrammetry to accurately reconstruct three-dimensional shape of an aircraft component is presented. This technique, which has matured significantly throughout the years, is originally an optical method to measure distances with high accuracy. In this work, images of the object are taken from several positions using single digital camera. Circular markers are distributed over the surfaces of the object in order to improve the accuracy of the reconstructed object. The accuracy of the reconstruction process is checked by comparing several measurements using caliper with the distance obtained by photogrammetry. The results show that the differences is less than 0.1%

Antibacterial potential of nudibranch-associated bacteria from Saparua and Nusa Laut Islands, Indonesia

Infections caused by multidrug-resistant bacteria are the international health issue that triggers the urgency of finding new antibacterial agents. The aim of this study was to obtain the nudibranchs-associated bacteria that have bioactivity against multidrug-resistant bacteria. A total of 13 species of nudibranch were identified based on morphological characterization. Overlay methods were used for the screening of the isolates bioactivity against six pathogenic multidrug-resistant bacteria. The Minimum Inhibition Concentration (MIC) of the crude extract was evaluated against Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Bacillussubtilis, Klebsiella pneumonia, Micrococcus luteus,and Extended Spectrum Beta Lactamases E. coli (ESBL) using MTT method. A total of 145 isolates were obtained which eleven of the isolates showed antibacterial activity against the pathogenic bacteria. The MIC tests showed that the best activity was isolate SM-S-9-15 and SM-N-3-7. The methanolic extract of isolate SM-S-9-15 active to all of the pathogenic bacteria, while the ethyl acetate extract of the isolate SM-N-3-7 active to the E. coli, B. subtilis, K. pneumoniaat the concentration of 500 g/mL. According to 16S ribosomal RNA gene sequence-based identification, all active isolates belong to Virgibacillusmarismortui, V. dokdonensis, Bacilluskochii, Vibrioalgynoliticus,and Pseudoalteromonaspiscicida

Model-independent Approach of the JUNO 8B Solar Neutrino Program

The physics potential of detecting 8B solar neutrinos will be exploited at the Jiangmen Underground Neutrino Observatory (JUNO), in a model-independent manner by using three distinct channels of the charged current (CC), neutral current (NC), and elastic scattering (ES) interactions. Due to the largest-ever mass of 13C nuclei in the liquid scintillator detectors and the expected low background level, 8B solar neutrinos are observable in the CC and NC interactions on 13C for the first time. By virtue of optimized event selections and muon veto strategies, backgrounds from the accidental coincidence, muon-induced isotopes, and external backgrounds can be greatly suppressed. Excellent signal-to-background ratios can be achieved in the CC, NC, and ES channels to guarantee the observation of the 8B solar neutrinos. From the sensitivity studies performed in this work, we show that JUNO, with 10 yr of data, can reach the 1σ precision levels of 5%, 8%, and 20% for the 8B neutrino flux, sin 2 θ 12 , and Δ m 21 2 , respectively. Probing the details of both solar physics and neutrino physics would be unique and helpful. In addition, when combined with the Sudbury Neutrino Observatory measurement, the world's best precision of 3% is expected for the measurement of the 8B neutrino flux

Damping signatures at JUNO, a medium-baseline reactor neutrino oscillation experiment

We study damping signatures at the Jiangmen Underground Neutrino Observatory (JUNO), a medium-baseline reactor neutrino oscillation experiment. These damping signatures are motivated by various new physics models, including quantum decoherence, nu(3) decay, neutrino absorption, and wave packet decoherence. The phenomenological effects of these models can be characterized by exponential damping factors at the probability level. We assess how well JUNO can constrain these damping parameters and how to disentangle these different damping signatures at JUNO. Compared to current experimental limits, JUNO can significantly improve the limits on tau(3)/m(3) in the nu(3) decay model, the width of the neutrino wave packet sigma(x), and the intrinsic relative dispersion of neutrino momentum sigma(rel)

JUNO physics and detector

The Jiangmen Underground Neutrino Observatory (JUNO) is a 20 kton liquid scintillator detector in a laboratory at 700-m underground. An excellent energy resolution and a large fiducial volume offer exciting opportunities for addressing many important topics in neutrino and astro-particle physics. With six years of data, the neutrino mass ordering can be determined at a 3-4 sigma significance and the neutrino oscillation parameters sin(2 )theta(12), Delta m(21)(2), and vertical bar Delta m(32)(2)vertical bar can be measured to a precision of 0.6% or better, by detecting reactor antineutrinos from the Taishan and Yangjiang nuclear power plants. With ten years of data, neutrinos from all past core-collapse supernovae could be observed at a 3 sigma significance; a lower limit of the proton lifetime, 8.34 x 10(33) years (90% C.L.), can be set by searching for p -> (nu) over barK(+); detection of solar neutrinos would shed new light on the solar metallicity problem and examine the vacuum-matter transition region. A typical core-collapse supernova at a distance of 10 kpc would lead to similar to 5000 inverse-beta-decay events and similar to 2000 (300) all-flavor neutrino-proton (electron) elastic scattering events in JUNO. Geo-neutrinos can be detected with a rate of similar to 400 events per year. Construction of the detector is very challenging. In this review, we summarize the final design of the JUNO detector and the key R&D achievements, following the Conceptual Design Report in 2015 (Djurcic et al., 2015). All 20-inch PMTS have been procured and tested. The average photon detection efficiency is 28.9% for the 15,000 MCP PMTS and 28.1% for the 5000 dynode PMTS, higher than the JUNO requirement of 27%. Together with the >20 m attenuation length of the liquid scintillator achieved in a 20-ton pilot purification test and the >96% transparency of the acrylic panel, we expect a yield of 1345 photoelectrons per MeV and an effective relative energy resolution of 3.02%/root E(MeV) in simulations (Abusleme et al., 2021). To maintain the high performance, the underwater electronics is designed to have a loss rate <0.5% in six years. With degassing membranes and a micro-bubble system, the radon concentration in the 35 kton water pool could be lowered to <10 mBq/m(3). Acrylic panels of radiopurity <0.5 ppt U/Th for the 35.4-m diameter liquid scintillator vessel are produced with a dedicated production line. The 20 kton liquid scintillator will be purified onsite with Alumina filtration, distillation, water extraction, and gas stripping. Together with other low background handling, singles in the fiducial volume can be controlled to similar to 10 Hz. The JUNO experiment also features a double calorimeter system with 25,600 3-inch PMTS, a liquid scintillator testing facility OSIRIS, and a near detector TAO. (JUNO Collaboration

Boundary element analysis of cracks in shear deformable plates and shells

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