A Procedure for the Fatigue Life Prediction of Straight Fibers Pneumatic Muscles

Different from the McKibben pneumatic muscle actuator, the straight fibers one is made of an elastomeric tube closed at the two ends by two heads that ensure a mechanical and pneumatic seal. High stiffness threads are placed longitudinally into the wall of the tube while external rings are placed at some sections of it to limit the radial expansion of the tube. The inner pressure in the tube causes shortening of the actuator. The working mode of the muscle actuator requires a series of critical repeated contractions and extensions that cause it to rupture. The fatigue life duration of a pneumatic muscle is often lower than traditional pneumatic actuators. The paper presents a procedure for the fatigue life prediction of a straight-fibers muscle based on experimental tests directly carried out with the muscles instead of with specimens of the silicone rubber material which the muscle is made of. The proposed procedure was experimentally validated. Although the procedure is based on fatigue life duration data for silicone rubber, it can be extended to all straight-fibers muscles once the fatigue life duration data of any material considered for the muscles is known.

Risk of Exposure to COVID-19: Visit Duration Data Can Inform Our Daily Activities Choices: An Epidemiological Investigation Using Community Mobility Data from the Metropolitan Area of Genoa, Italy

COVID-19 spreads mainly among people who are in close contact. Policymakers mostly resorted to normative measures to limit close contacts and impose social distancing. Our study aimed to estimate the risk of exposure to COVID-19 by location and activity in crowded metropolitan areas. The risk of exposure to COVID-19 was defined as the product of crowding (people within a six feet distance) and exposure duration (fraction of 15 min). Our epidemiological investigation used aggregated and anonymized mobility data from Google Maps to estimate the visit duration. We collected visit duration data for 561 premises in the metropolitan area of Genoa, Italy from October 2020 to January 2021. The sample was then clustered into 14 everyday activities, from grocery shopping to the post office. Crowding data by activity were obtained from pre-existing building norms and new government measures to contain the pandemic. The study found significant variance in the risk of exposure to COVID-19 among activities and, for the same activity, among locations. The empirical determination of the risk of exposure to COVID-19 can inform national and local public health policies to contain the pandemic’s diffusion. Its simple numerical form can help policymakers effectively communicate difficult decisions affecting our daily lives. Most importantly, risk data by location can help us rethink our daily routine and make informed, responsible choices when we decide to go out.

Shared or Separate Representations? The Spanish Palatal Nasal in Early Spanish/English Bilinguals

The purpose of this study is to examine phonetic interactions in early Spanish/English bilinguals to see if they have established a representation for the Spanish palatal nasal /ɲ/ (e.g., /kaɲon/ cañón ‘canyon’) that is separate from the similar, yet acoustically distinct English /n+j/ sequence (e.g., /kænjn̩/ ‘canyon’). Twenty heritage speakers of Spanish completed a delayed repetition task in each language, in which a set of disyllabic nonce words were produced in a carrier phrase. English critical stimuli contained an intervocalic /n+j/ sequence (e.g., /dɛnjɑ/ ‘denya’) and Spanish critical stimuli contained intervocalic /ɲ/ (e.g., /deɲja/ ‘deña’). We measured the duration and formant contours of the following vocalic portion as acoustic indices of the /ɲ/~/n+j/ distinction. The duration data and formant contour data alike show that early bilinguals distinguish between the Spanish /ɲ/ and English /n+j/ in production, indicative of the maintenance of separate representations for these similar sounds and thus a lack of interaction between systems for bilinguals in this scenario. We discuss these discrete representations in comparison to previous evidence of shared and separate representations in this population, examining a set of variables that are potentially responsible for the attested distinction.

Frequency of Arthropods Daily Visits on Centella asiatica L. and Synedrlla nodiflora (L) Gaertn in the Wonosari Singosari Tea Plantation Area in Malang Regency

The purpose of this research is to find the temporal distribution pattern of the visiting of Arthropods on these wild plants. This descriptive and explorative research was carried out in the Wonosari tea plantation, Singosari, Malang in March 2011. The visual control method for these purposes was adopted from the modification of the visual control method developed by Frei and Manhart (1992). Observations were done with 10 repeats, consisting of 10 tempos with 15 minutes duration. Data relating to the temporal distribution of Arthropods on these wild plants were presented as diagrams and interpreted descriptively. The result of this research can be described as follows: There was a difference between the temporal distribution of Arthropod visiting the wild plants Centella asiatica L. and Synedrella nodiflora (L) Gaertn. For the Centella asiatica L the highest visitor number was at 10.00 am while for the wild plant Synedrella nodiflora (L) Gaertn it was at 11.20 am.

Reconstructing floods in small-medium scale data-scarce catchments using field interview data and hydrodynamic modelling

<p>We develop a technique for reconstructing floods in small-scale data scarce regions using field interview data and hydro-dynamic modelling. The field interview data consist of flood depths and duration data collected from 300 buildings from a flood event in 2017 in Suleja/Tafa area, Nigeria. The flood event resulted from an overflow of water from five river reaches. The hydrodynamic model utilized, called CAESER LisFLOOD, is an integration of a landscape evolution model (CAESER) and a hydraulic model (LisFLOOD-FP). We employ three steps to reconstruct the 2017 Suleja/Tafa flood event. Firstly, we use a linearly increasing hydrograph to; (a) calibrate Manning’s coefficient and (b) determine optimal peak discharge on each reach. This was carried out by minimizing the Root Mean Square Error (RMSE) between the distributed observed flood depths and the simulated flood depths. Secondly, we use synthetic hydrographs with durations between 6, 12, 18, 20, 24 hours, having peak discharge (extracted from the previous step), to simulate flows on all upstream reaches. Using collected flood duration data, we minimized RMSE between distributed observed flood duration and simulated flood duration to determine optimal flow durations on each upstream reach. In the last step, utilizing peak discharge and flow duration for all upstream reaches, we carried out multiple spatial and temporal iterations to match downstream peak discharge. Thereafter, we use determined upstream hydrographs with their relative catchment response timing to simulate the entire river network. Minimum RMSE computed for the entire river network was between ±15 cm of many current studies that use distributed observed data to calibrate flood models. The method developed in this study is useful for simulating floods in regions where data such as high resolution DEMs, river bathymetry and river discharge are limited. In addition, the study extends current knowledge, on utilizing distributed flood data to determine peak discharge, from a single to multiple river networks.</p>