Miracle-dz/UniFAR-FTUs huggingface dataset:
Pulsed instability in rocket motors - A comparison between predictions and experiments

A series of 18 pulsed motor tests was conducted in heavy-wall solid rocket motors having an internal case diameter of 8.38 cm. The motor length was varied from 0.61 -1.22 m. Three related reduced-smoke propellants and four different grain designs were tested. All of the motors were linearly stable and all were pulsed into nonlinear instability. The data from this test series were used to evaluate the validity of previously developed pulser models and to evaluate the ability of a previously developed nonlinear instability analysis to predict the observed trends in the data. In most cases, the combined pulser and chamber stability models were found to be capable of predicting measured pulse amplitudes to within 10%. The ejecta pulser model had to be modified to account for the effect of internal wave reflection when propellant grain extended up to the nozzle entrance plane. The nonlinear instability analysis demonstrated the ability to predict many of the observed wave amplitude and shift trends in the data as a function of propellant and grain design. This combined analytical/experimental investigation also provides additional insight into the nature of nonlinear pulse triggered instability and the factors that influence its occurrence and severity.
Nucleation Experiments with Monodisperse NaCl Aerosols

Abstract Nucleation experiments with monodisperse NaCl aerosols showed good agreement with the Kohler theory relating the critical super-saturation Sc to the dry size. Aerosols produced by condensing NaCl showed the same Sc as those produced by evaporating aqueous NaCl solution droplets. This indicates that if there is an energy barrier in going from a dry NaCl particle to a solution droplet, this energy barrier is small. The fact that the evaporation aerosol particles are cubical crystals and the condensation aerosols are amorphous spheres is shown to make no difference in the nucleation threshold. The investigation also gives insights into the performance of the equipment used, especially the commercial electrostatic aerosol classifier and the vertical flow thermal diffusion chamber developed in this laboratory. When operating this chamber in the isothermal mode, a 36% upper limit was found on the uncertainty in Sc due to index of refraction sensitivity in sizing the water drops. Within this range of un.
Cell Phone Social Media Use and Psychological Well-Being in Young Adults: Implications for Internet-Related Disorders

Internet-related disorders are on the rise and increasing cell phone social media use may be one of the reasons for these disorders. To better understand internet-related disorders, we aim to explore the psychological and social aspects of cell phone social media behaviors. We hypothesized that, according to humanistic theories of positive functioning, cell phone social media connectedness to self (engagement, interest, pleasure, sense of enjoyment, meaningfulness, purposefulness, optimism, acceptance, and feeling accomplished) would relate positively to psychological well-being of undergraduate students. We also hypothesized that, according to Maslow’s hierarchy of needs, cell phone social media connectedness to others (affiliation, feeling rewarded, being liked by others, and contributions to the well-being of others) would relate positively to the psychological well-being of undergraduate students. During the fall of 2019, 523 (75.4% female) undergraduate students from a large public university participated in this study by completing validated quantitative surveys on their cell phone use and psychological well-being. Spearman’s rho and ordinal logistics were implemented to analyze the findings. Correlational data showed that cell phone social media connectedness to self and cell phone social media connectedness to others were positively associated with the psychological well-being of undergraduate students. Ordinal logistics showed higher odds of psychological well-being occurring with cell phone social media connectedness to self and cell phone social media connectedness to others. Cell phone social media connectedness to self significantly predicted psychological well-being with the medium effect, whereas cell phone social media connectedness to others was not a significant predictor of the psychological well-being of undergraduate students. An increase in cell phone social media connectedness to self and an increase in cell phone social media connectedness to others of undergraduate students helped them improve their psychological well-being. Cell phone social media connectedness to self significantly predicted but cell phone social media connectedness to others did not predict the psychological well-being of undergraduate students, which may have implications for the research pertaining to behavioral addiction and may help better understand internet-related disorders.
Physiological-based Driver Monitoring Systems: A Scoping Review

A physiological-based driver monitoring system (DMS) has attracted research interest and has great potential for providing more accurate and reliable monitoring of the driver’s state during a driving experience. Many driving monitoring systems are driver behavior-based or vehicle-based. When these non-physiological based DMS are coupled with physiological-based data analysis from electroencephalography (EEG), electrooculography (EOG), electrocardiography (ECG), and electromyography (EMG), the physical and emotional state of the driver may also be assessed. Drivers’ wellness can also be monitored, and hence, traffic collisions can be avoided. This paper highlights work that has been published in the past five years related to physiological-based DMS. Specifically, we focused on the physiological indicators applied in DMS design and development. Work utilizing key physiological indicators related to driver identification, driver alertness, driver drowsiness, driver fatigue, and drunk driver is identified and described based on the PRISMA Extension for Scoping Reviews (PRISMA-Sc) Framework. The relationship between selected papers is visualized using keyword co-occurrence. Findings were presented using a narrative review approach based on classifications of DMS. Finally, the challenges of physiological-based DMS are highlighted in the conclusion. Doi: 10.28991/CEJ-2022-08-12-020 Full Text: PDF
On the response of polarimetric synthetic aperture radar signatures at 24-cm wavelength to sea ice thickness in Arctic leads

We investigate observationally and theoretically the response of polarimetric backscattering at 24-cm wavelength to the thickness of Arctic sea ice in leads and first-year ice features. We employ backscattering data acquired by the Jet Propulsion Laboratory airborne synthetic aperture radar (SAR) during March 1988 in the Beaufort Sea, together with nearly simultaneous passive microwave imagery acquired by the U.S. Navy Ka band radiometric mapping system. We find that 24-cm copolar ratios and copolar phases vary strongly with apparent ice thickness. We observe copolar phase shifts between −10° and −50° (relative to multiyear ice phases) for new ice features in the imagery, as well as positive copolar phases in a first-year ice feature. Copolar ratios also vary with apparent thickness, from values larger than those expected theoretically for seawater to values slightly lower than those expected for thick ice. We derive a signature model based on scattering from a rough air/sea ice interface with realistic vertical profiles of brine volume and relative permittivity beneath. Model predictions for copolar ratios and phases show ice thickness-dependent variations consistent with those observed. We present simulation results showing that plausible ice thickness variations between pixels in a multilook average diminish, but do not eliminate, the signature response to thickness. This suggests that direct thickness estimation of sea ice in leads may be possible using polarimetric SAR at wavelengths of 24 cm or longer.
Antibiotic susceptibility analysis of Escherichia coli as the cause of urinary tract infection

The incidence of urinary tract infection (UTI) in Indonesia is still quite high. The UTIs are generally treated with antibiotic. However, the use of antibiotics has recently increased tremendously thus triggering bacterial resistance. This study was to analyze the susceptibility of the Escherichia coli as the cause of the UTI to 15 antibiotics at the UPTD Health Laboratory Center of Maluku Province. The study was an experimental laboratory study using the disk diffusion method. The antibiotic disc was placed on the media and the inhibition zone against E. coli was measured. The results showed that the E. coli was resistant (26.67%) to 4 types of antibiotics, namely amoxilin, ampicillin, sulfametazole dan penicillin. Meanwhile, E. coli was sensitive (46.66%) to 7 types of antibiotics, namely kanamycin, gentamicin, subactam ampicillin, chloramphenicol, amikacin, ceffazedine and azithromycin. Furthermore, E. coli was intermediate (26.67%) against 4 types of antibiotics, namely ciprofloxacin, ceptriaxone, cefoxitin and colistin. This study concluded that of the 15 antibiotics tested, gentamicin, amikacin, and kanamycin were the most effective antibiotics in inhibiting the growth of E. coli that causes UTI. Nevertheless, the appropriate choice of antibiotic needs to be adjusted only by physicians based on local, regional and national patterns of susceptibility.
The google classroom online learning platform the use analysis for biology students

The Covid-19 virus epidemic that is still spreading throughout the world has caused a shift in the learning process, where previous interactions occurred face-to-face, and then the interaction switched through the help of a platform. This study examines the experience of using Google Classroom for biology learning media in eleventh grade during the Covid-19 virus outbreak. This research takes place from December 2021 to March 2022. This type of research is descriptive quantitative. The population of this study was sampled using proportional random sampling. This study involved 45 students in the eleventh grade majoring in natural science at State Senior High School 1, Kotanopan. Data was collected through questionnaires and documents. A closed questionnaire with 45 validated and distributed items were used to collect data. Technical analysis of the data used descriptive quantitative. Based on the research, the following are the results of the analysis of the use of Google Classroom for biology in eleventh grade: 1) Overall, the experience of using Google Classroom as a means of learning biology is excellent, with a score of 81.48%. 2) A study of the factors supporting the adoption of Google Classroom as a biology learning platform was good, with 66.22%. 3) The study of the barriers to adopting Google Classroom as a biology learning platform was hampered by 33.2%. During the Covid-19 virus outbreak, online biology learning through Google Classroom can complement classroom teaching.
Analysis of the Social Challenge of the City of Barcelona Under the Model
of the Quintuple Helix in a Covid-19 Context

This study performed an exhaustive analysis of the context that has given rise to the related phenomena of tourism-phobia and touristification in the city of Barcelona. The Quintuple Helix innovation model developed by Carayannis, Barth, and Campbell is used as a model of open innovation to present a new perspective through which to counter the challenges of today's society. The Quintuple Helix supports the formation of a win-win situation between ecology, knowledge, and innovation, thereby creating synergies between economy, society, and democracy. The research also draws on the strategic city plan of Barcelona, articles in the specialized press, and reports presenting the opinions of a diverse range of professionals. The statistical data from official bodies and the answers to a questionnaire are validated through the World Tourism Organisation (UNWTO) model. The research analysis is a process of innovation that has not yet begun, thereby highlighting exciting questions about the potential role of the different actors involved. Our results support the idea that tourism-phobia in Barcelona remains uncontrolled and that a lack of understanding exists between the different actors. This leads to a fragile innovation process that is incapable of solving the social challenges posed by the tourism monoculture. The study offers a precise diagnosis of the actors' lack of control and cohesion and suggests that policymakers rethink how to manage the city together with tourism rather than focusing solely on tourist activities. Finally, we find that the current context of the Covid-19 pandemic perpetuates a model of unsustainable tourism-philia that will eventually feed back into tourism-phobia.
The critical thinking skills and independent learning analysis: The flipped classroom based on blended learning

The results of observations in the Biology Education Study Program of Sembilanbelas November Kolaka University, until now the lecture activities carried out in general still use the conventional model which causes students to tend to be passive, the low independence of student learning which hinders students' thinking skills. For this reason, an innovative lecture model is needed that can develop and improve students' critical thinking skills and independence. The purpose of this study was to determine the critical thinking skills and independent learning of students through the flipped classroom model based on blended learning. This research is a quasi-experimental research using one group pretest-posttest design. Data collection by tests and questionnaires. Data were analyzed descriptively quantitatively and one sample t test. The results showed that the value of critical thinking skills of paired samples t-test obtained a significance level (p) of 0.00 < 0.05. For independent learning as a whole, the results of the paired samples t-test obtained a significance level (p ) of 0.00 < 0.05. So it can be concluded that students' critical thinking skills and independence are better when applying the blended learning-based flipped classroom model.
MAGNNETO: A Graph Neural Network-Based Multi-Agent System for Traffic Engineering

Current trends in networking propose the use of Machine Learning (ML) for a wide variety of network optimization tasks. As such, many efforts have been made to produce ML-based solutions for Traffic Engineering (TE), which is a fundamental problem in Internet Service Provider (ISP) networks. Nowadays, state-of-the-art TE optimizers rely on traditional optimization techniques, such as Local search, Constraint Programming, or Linear programming. In this paper, we present MAGNNETO, a distributed ML-based framework that leverages Multi-Agent Reinforcement Learning and Graph Neural Networks for distributed TE optimization. MAGNNETO deploys a set of agents across the network that learn and communicate in a distributed fashion via message exchanges between neighboring agents. Particularly, we apply this framework to optimize link weights in Open Shortest Path First (OSPF), with the goal of minimizing network congestion. In our evaluation, we compare MAGNNETO against several state-of-the-art TE optimizers in more than 75 topologies (up to 153 nodes and 354 links), including realistic traffic loads. Our experimental results show that, thanks to its distributed nature, MAGNNETO achieves comparable performance to state-of-the-art TE optimizers with significantly lower execution times. Moreover, our ML-based solution demonstrates a strong generalization capability to successfully operate in new networks unseen during training.
Psychometric Hepatic Encephalopathy Score for the Diagnosis of Minimal Hepatic Encephalopathy in Thai Cirrhotic Patients

The psychometric hepatic encephalopathy score (PHES) is the gold standard for diagnosing minimal hepatic encephalopathy (MHE). Screening for MHE is frequently overlooked in clinical practice due to time constraints. Furthermore, the simplified animal naming test (S-ANT1) is a new simple tool for evaluating MHE in cirrhotic patients. The purpose of this study was to standardize the PHES in a healthy Thai population, assess the prevalence of MHE, and validate the S-ANT1 in detecting MHE in patients with cirrhosis. The study included 194 healthy controls and 203 cirrhotic patients without overt HE. Psychometric tests and the S-ANT1 were administered to all participants. Multiple linear regression was used to analyze factors related to PHES results, and formulas were developed to predict the results for each PHES subtest. In healthy controls, age and education were predictors of all five subtests. The PHES of the control group was −0.26 ± 2.28 points, and the threshold for detecting MHE was set at ≤ −5 points. The cirrhotic group had PHES values of −2.6 ± 3.1 points. Moreover, MHE was found to be present in 26.6% of cirrhotic patients. S-ANT1 had a moderate positive correlation with PHES (r = 0.44, p < 0.001). S-ANT1 < 22 named animals detected MHE with a sensitivity of 71.2%, specificity of 65%, and area under the receiver operating curve of 0.68 (p < 0.001). In conclusion, Thai PHES normative data have been developed to detect MHE in cirrhotic patients who do not have overt HE. The optimal cutoff for detecting MHE in Thai cirrhotic patients was PHES ≤ −5 points and S-ANT1 < 22 named.
Analysis of second-harmonic generation of Lamb modes using a modal analysis approach

An effective technique for analyzing the generation of second harmonics of Lamb modes in elastic plates is presented. The nonlinearity of the wave equation governing the wave propagation ensures that there is second-harmonic generation accompanying primary Lamb mode propagation. This nonlinearity may be treated as a second-order perturbation of the linear elastic response. Using a second-order perturbation approximation and a modal analysis approach, the complicated problems of the generation of second harmonics of Lamb modes have been investigated. The fields of the second harmonics of Lamb modes in elastic plates are considered as superpositions of the fields of a series of double-frequency Lamb modes. The solutions provide physical insight into the generation of second harmonics with a cumulative growth effect, and the corresponding second-harmonic solutions. Although Lamb modes are dispersive, the cumulative growth effect of the second harmonics does exist under some conditions. The influence of Lamb .
Leaded aviation gasoline exposure risk and child blood lead levels

Abstract Lead-formulated aviation gasoline (avgas) is the primary source of lead emissions in the United States today, consumed by over 170,000 piston-engine aircraft (PEA). The U.S. Environmental Protection Agency (EPA) estimates that four million people reside within 500m of a PEA-servicing airport. The disposition of avgas around such airports may be an independent source of child lead exposure. We analyze over 14,000 blood lead samples of children (≤5 y of age) residing near one such airport—Reid-Hillview Airport (RHV) in Santa Clara County, California. Across an ensemble of tests, we find that the blood lead levels (BLLs) of sampled children increase in proximity to RHV, are higher among children east and predominantly downwind of the airport, and increase with the volume of PEA traffic and quantities of avgas sold at the airport. The BLLs of airport-proximate children are especially responsive to an increase in PEA traffic, increasing by about 0.72 μg/dL under periods of maximum PEA traffic. We also observe a significant reduction in child BLLs from a series of pandemic-related interventions in Santa Clara County that contracted PEA traffic at the airport. Finally, we find that children’s BLLs increase with measured concentrations of atmospheric lead at the airport. In support of the scientific adjudication of the EPAs recently announced endangerment finding, this in-depth case study indicates that the deposition of avgas significantly elevates the BLLs of at-risk children.
Investigation of the spatial variations in synthetic aperture radar backscatter in western Dronning Maud Land, Antarctica

C-band SAR observations show that backscatter varies significantly across small scales (tens of kilometers) in western Dronning Maud Land. Generally, backscatter was found to diminish with altitude reflecting lower accumulation and reduced ice inclusions in the firn of the percolation zone at higher elevations. Reference to (incomplete) mass balance data suggests an anticorrelation between backscatter and net balance, although more data are needed to confirm the trend. Even within the percolation zone, areas of low backscatter (<-12 dB) exist. These are uncorrelated with altitude above sea level. Using a Rayleigh backscatter model, we show that backscatter over such regions may represent differences in grain sizes. The application of a buried-layers model did not accurately estimate backscatter from these regions. We suggest that these regions occupy exposed positions subject to increased wind sublimation which, in turn, results in smaller grain sizes in the firn and therefore reduced backscatter. The Radarsat Antarctica Mapping Mission SAR mosaic indicates such regions occur in Coates Land, near the edge of the Antarctic Plateau, and on exposed promontories elsewhere in East Antarctica. More information regarding the structure of the firn and the mass balance of the region is needed before we can definitively explain controls on backscatter and understand the climatology of the low backscatter zones.
Surface atomic geometry of Si(001)-(2×1): A low-energy electron-diffraction structure analysis

The reconstruction of the Si(001)-2×1 surface consists of asymmetric and buckled Si dimers. The vertical separation between the up and the down atom within the dimer is about 0.72±0.05 A and the dimer bond length of 2.24±0.08 A has been found to be slightly smaller than the Si-Si distance in the bulk. The tilt of the dimer is 19±2°. The formation of Si dimers induces pronounced distortions in the substrate that were detectable down to the fifth Si layer. The structure determination is based on two independent low-energy electron-diffraction data sets taken in two different laboratories. The structural results agree well within the error limits, though noticeable differences occur between the experimental data sets. These differences in the experimental data can possibly be attributed to different preparation procedures.
A near-exact method for solving the log-truck scheduling problem

We propose a solution method for the log-truck scheduling problem, which is a generalisation of the pick-up and delivery problem with time windows. Our approach is based on column generation and pseudo branch and price. Each column in the proposed mathematical model represents one feasible route for one truck. We start by designing a priori an initial set of routes. Then, the subproblem, which is a constrained shortest path problem, is solved by applying a k-shortest path algorithm. Numerical results from a case study are presented.