scholarly journals Resistência ao impacto de revestimentos para fundições odontológicas, em diversas condições de temperatura no forno

2021 ◽  
pp. 87-97
Author(s):  
Léo Werner Süffert ◽  
Fernando Lyra Martins
Keyword(s):  
Heat Loss ◽  
Furnace Temperature ◽  
Time Intervals ◽  
Dental Casting ◽  
Temperature Loss ◽  
The Impact

The impact strenght of four dental casting investments is investigated as a function of heat loss after removal of tu a furnace temperature of 700ºC, at different time intervals. Attention is called to the fact hat a graphical relationship between temperature loss and lmpact strenght, even hough obtained from averages of 10 experiments, but without a statistical analysls, may induce to erroneous conclusions.

scholarly journals Perda de temperatura em revestimentos odontológicos, após sua remoção do forno

2021 ◽  
pp. 99-113
Author(s):  
Fernando Lyra Martins ◽  
Léo Werner Süffert ◽  
Ennio Pessoa
Keyword(s):  
Heat Loss ◽  
Technical Detail ◽  
Furnace Temperature ◽  
Time Intervals ◽  
Casting Operation ◽  
Dental Casting ◽  
Operation Temperature

The time elepsed between the removal from the furnace of a castin cylinder and the casting proper, depends on the knowledge and ability of the operator. The heat loss, after removal of a furnace temperature of 700ºC at different time intervals, was mensured in four dental casting investiments, using different volumes of investment, with or without the protection of a casting ring and with or without asbestos liner. The results, presented in the form of tables and graphs, tell us about the importance of this additional technical detail, in the dental casting operation. Temperature losses in the order of from 100º to 200ºC were verified, already two minutes after removal from the furnace.

scholarly journals Impact of the Coronavirus Pandemic Lockdown on Atmospheric Nanoparticle Concentrations in Two Sites of Southern Italy

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 352
Author(s):  
Adelaide Dinoi ◽  
Daniel Gulli ◽  
Ivano Ammoscato ◽  
Claudia R. Calidonna ◽  
Daniele Contini
Keyword(s):  
Particle Number ◽  
Southern Italy ◽  
Time Intervals ◽  
Atmospheric Particle ◽  
Total Particle Number ◽  
Total Particle ◽  
Consequent Reduction ◽  
Containment Measures ◽  
Coronavirus Infection ◽  
The Impact

During the new coronavirus infection outbreak, the application of strict containment measures entailed a decrease in most human activities, with the consequent reduction of anthropogenic emissions into the atmosphere. In this study, the impact of lockdown on atmospheric particle number concentrations and size distributions is investigated in two different sites of Southern Italy: Lecce and Lamezia Terme, regional stations of the GAW/ACTRIS networks. The effects of restrictions are quantified by comparing submicron particle concentrations, in the size range from 10 nm to 800 nm, measured during the lockdown period and in the same period of previous years, from 2015 to 2019, considering three time intervals: prelockdown, lockdown and postlockdown. Different percentage reductions in total particle number concentrations are observed, −19% and −23% in Lecce and −7% and −4% in Lamezia Terme during lockdown and postlockdown, respectively, with several variations in each subclass of particles. From the comparison, no significant variations of meteorological factors are observed except a reduction of rainfall in 2020, which might explain the higher levels of particle concentrations measured during prelockdown at both stations. In general, the results demonstrate an improvement of air quality, more conspicuous in Lecce than in Lamezia Terme, during the lockdown, with a differed reduction in the concentration of submicronic particles that depends on the different types of sources, their distance from observational sites and local meteorology.

Abstract P99: Impact of the Covid-19 Pandemic on Stroke Thrombolysis Rate and Delay to Thrombolysis Treatment in a Regional Stroke Centre in London, UK

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Brian Drumm ◽  
Paul Bentley ◽  
Zoe Brown ◽  
Lucio D’Anna ◽  
Tsering Dolkar ◽  
...  
Keyword(s):  
Arrival Time ◽  
Negative Impact ◽  
Public Awareness ◽  
Stroke Severity ◽  
Time Intervals ◽  
Neurological Outcomes ◽  
Stroke Thrombolysis ◽  
Prehospital Delays ◽  
The Impact ◽  
Stroke Centre

Introduction: There are reports of changes in the numbers of stroke admissions and time intervals to receiving emergency treatments during the COVID-19 pandemic. We examined the impact of the COVID-19 pandemic on the stroke thrombolysis rate and delay to thrombolysis treatment in a regional stroke centre in London, UK. Methods: COVID-19 testing began at our hospital on 3 March 2020. Clinical data for all acute stroke admissions were routinely collected as part of a national Sentinel Stroke National Audit Programme (SSNAP) and all thrombolysis data were entered into our local thrombolysis database. We retrospectively extracted the relevant patient data for the period of March to May 2020 (COVID group) and compared to the same period in 2019 (pre-COVID group). Results: Compared with pre-COVID, there was a 17.5% fall in total stroke admissions (from 315 to 260) during COVID; but there were no significant differences in the demographics, stroke severity, proportions with known time of onset, or median onset-to-arrival time. The thrombolysis rates amongst ischemic strokes were not significantly different between the two groups (59/260=23% pre-COVID vs. 41/228=18% COVID, p=.19). For thrombolysis patients, their stroke severity and demographics were similar between the two both groups. Median onset-to-needle time was significantly longer by 22 minutes during COVID [127 (IQR 94-160) vs. 149 (IQR 110-124) minutes, p=.045]; this delay to treatment was almost entirely due to a longer median onset-to-arrival time by 16 minutes during COVID (p=.029). Favorable early neurological outcomes post-thrombolysis (defined as an improvement in NIHSS by ≥4 points at 24 hours) were similar (45% vs. 46%, p=.86). Conclusion: COVID-19 pandemic had a negative impact on prehospital delays which in turn significantly increased onset-to-needle time, but without affecting the chance of a favorable early neurological outcome. Our data highlight the need to maintain public awareness of taking immediate action when stroke symptoms occur during the COVID-19 pandemic.

Abstract 13248: The Impact of Instructions for Covering the Mouth and the Nose on Dispatch-Assisted Cardiopulmonary Resuscitation

Circulation ◽  
2021 ◽  
Vol 144 (Suppl_2) ◽  
Author(s):  
Hidetada Fukushima ◽  
Hideki Asai ◽  
Koji Yamamoto ◽  
Yasuyuki Kawai
Keyword(s):  
Cardiopulmonary Resuscitation ◽  
Median Time ◽  
Chest Compression ◽  
Fire Department ◽  
Emergency Call ◽  
Time Interval ◽  
Time Intervals ◽  
Median Time Interval ◽  
Study Results ◽  
The Impact

Introduction: Under the SARS-CoV-2 pandemic, rescuers are recommended to cover their mouth and nose with a facemask or a cloth as well as victim’s mouth and nose when performing cardiopulmonary resuscitation (CPR). However, its impact on dispatch-assisted CPR (DACPR) has not been investigated well. Hypothesis: DACPR including the instruction for covering the rescuer’s and the victim’s mouth and nose can significantly delay the start of the first chest compression. Methods: We retrospectively analyzed DACPR records of the Nara Wide Area Fire Department, covering population of 853,000/3361km 2 , in Japan. We investigated the key time intervals of 505 DACPR records between May 2020 and March 2021. We also compared the results to that of the same period in 2019 (535 records). Results: Dispatchers failed to provide mask instruction in 322 cases (63.8%). The median time interval from the emergency call and the start of CPR instruction was longer in 2020 (197 seconds vs 190 seconds, p=0.641). The time to the first chest compression was also delayed in 2020 (264 seconds vs 246 seconds, p=0.015). Among the cases that dispatchers successfully provided mask instruction (183 cases, 36.2%), median time intervals to the start of instruction and the first chest compression were relatively faster than cases without mask instruction (177 seconds vs 211 seconds and 254 seconds vs 269.5 seconds, respectively). Conclusions: Dispatchers failed to provide mask instruction in the majority of CA cases. However, our study results indicate that the impact of mask instruction on DACPR can be minor in terms of immediate CPR provision.

Departure Time Choice in Schedule-Based Transit Assignment

2021 ◽  
pp. 036119812110338
Author(s):  
Markus Friedrich ◽  
Matthias Schmaus ◽  
Jonas Sauer ◽  
Tobias Zündorf
Keyword(s):  
Travel Demand ◽  
Time Intervals ◽  
Transit Assignment ◽  
Common Assumption ◽  
Adaptation Time ◽  
Highly Sensitive ◽  
Departure Time ◽  
Departure Time Choice ◽  
Passenger Behavior ◽  
The Impact

This paper investigates existing departure time models for a schedule-based transit assignment and their parametrization. It analyzes the impact of the temporal resolution of travel demand and suggests functions for evaluating the adaptation time as part of the utility of a path. The adaptation time quantifies the time between the preferred and the scheduled departure times. The findings of the analysis suggested that travel demand should be discretized into intervals of 1 min, with interval borders right between the full minute, that is, ±0.5 min. It was shown that longer time intervals led to arbitrary run volumes, even for origin–destination pairs with just one transit line and a fixed headway. Although a linear relationship between adaptation time and adaptation disutility is a common assumption in several publications, it cannot represent certain types of passenger behavior. For some trip purposes, passengers may be insensitive to small adaptation times, but highly sensitive to large adaptations. This requires a nonlinear evaluation function.

scholarly journals Design of a computational model for multi-body contact of deformable bodies in the flowing fluid

2018 ◽  
Vol 157 ◽  
pp. 02012 ◽  
Author(s):  
Marián Handrik ◽  
Milan Vaško
Keyword(s):  
Computational Model ◽  
Time Intervals ◽  
Flowing Fluid ◽  
Body Contact ◽  
Impact Area ◽  
Deformable Bodies ◽  
Multi Body ◽  
The Impact ◽  
Design And Testing

The article deals with the design and testing of a computational model for multi-body contact of deformable bodies in the flowing fluid. The computational model will be designed to allow easy modify the impact area of deformable bodies and their shape. The computational model must allow the application of an endless cycle of bodies impact with the possibility of restarting and calculating the following time intervals for collision of bodies.

Changes in fish populations affected by the construction of the La Grande complex (Phase I), James Bay region, Quebec

1995 ◽  
Vol 73 (10) ◽  
pp. 1860-1877 ◽  
Author(s):  
Jean-Claude DesLandes ◽  
Sylvie Guénette ◽  
Yves Prairie ◽  
Réjean Fortin ◽  
Dominique Roy ◽  
...  
Keyword(s):  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Time Intervals ◽  
Complex Phase ◽  
Coregonus Artedii ◽  
Secondary Productivity ◽  
Longnose Sucker ◽  
The Impact

Catches per unit of effort (CPUE) with experimental gill nets, recruitment, growth, and condition were monitored between 1977 and 1992 to evaluate the impact of impoundment on the main fish species of La Grande 2, Opinaca, and Caniapiscau reservoirs and the Boyd–Sakami diversion. CPUE and recruitment of northern pike (Esox lucius) and lake whitefish (Coregonus clupeaformis) increased markedly at most stations after impoundment and decreased at the end of the series. The lake whitefish and cisco (Coregonus artedii) showed their most striking rise in CPUE at two bay stations of La Grande 2 and Opinaca reservoirs. CPUE and recruitment of the longnose sucker (Catostomus catostomus), white sucker (Catostomus commersoni), and lake trout (Salvelinus namaycush) (Caniapiscau) showed a general decrease following impoundment. CPUE for the walleye (Stizostedion vitreum) also decreased at several stations; however, the two most southerly stations in La Grande 2 reservoir and the Boyd–Sakami station showed high CPUE during the series. Concentration–redistribution phenomena explain part of the observed variations in CPUE. Correlation analyses showed that walleyes and white suckers were attracted to the warmer, more turbid stations, and that the high primary and secondary productivity of bay stations attracted the coregonines. Growth and condition of the main species increased during variable time intervals after impoundment and decreased at the end of the series.

scholarly journals Application of Mixed Linear Models in the Analysis of Road Surface Features

2015 ◽  
Vol 54 (1) ◽  
pp. 101-109 ◽  
Author(s):  
Jurgita Židanavičiūtė ◽  
Audrius Vaitkus
Keyword(s):  
Linear Models ◽  
Road Surface ◽  
Linear Regression Models ◽  
Mixed Linear Models ◽  
Time Intervals ◽  
Surface Strength ◽  
The Road ◽  
Unequally Spaced ◽  
Units Of Analysis ◽  
The Impact

The data were collected by researchers at the Road Research Institute, in a study investigating the impact of differentfactors on road surface strength. In this statistical analysis, we apply linear mixed models (LMMs) to clustered longitudinal data, inwhich the units of analysis (points in the road) are nested within clusters (sample of four different road segments), and repeatedmeasures of road strength in these different points are collected over time with unequally spaced time intervals. The data arebalanced – each cluster has the same number of units, which are measured at the same number of time points. Because of correlateddata and different clusters in which data could be correlated, linear regression models are not appropriate here, and therefore linearmixed models are applied.

Thermal Design of Pipelines – A Challenge for Flow Assurance in the Arctic

2021 ◽  
Author(s):  
Veerendhar Ponagandla ◽  
Liangjian Liu ◽  
Duane DeGeer
Keyword(s):  
Heat Loss ◽  
Optimal Solution ◽  
Thermal Design ◽  
The Arctic ◽  
Flow Assurance ◽  
Mackenzie Delta ◽  
Far North ◽  
Hypothetical Scenario ◽  
Surface Ice ◽  
The Impact

Abstract Increasing demand for energy is driving the need to explore the deeper oceans and the far north. While higher temperature, pressure and longer tie-backs are challenges going deep, highly sensitive environment is an issue exploring far north. The discovery of large reserves in the far north has brought the challenges of exploration, production, and transportation in the cold regions like Prudhoe Bay, the Mackenzie Delta, and the Arctic Islands into focus. To transport hydrocarbons to market, pipelines used in the Arctic have unique challenges and stringent design conditions that must be met to ensure reliable operations in such remote and sensitive environments. To avoid flow assurance risks, the adage “the hotter the better” is in stark contrast to the sensitive nature of the Arctic environment to temperature changes, and where “the colder the better” is more appropriate. Permafrost, and its potential disturbance, is the most important factor to be considered for pipeline thermal design. High temperatures can disturb the in-situ state of the permafrost, causing settlement and instability in the permafrost zone. Also, high pipeline temperatures demand deep trenches to avoid melting the surface ice, challenging installation and increasing CAPEX. Designing the pipeline to maintain high internal fluid temperatures to reduce flow assurance risks and lower pipeline outer temperatures to minimize the impact on the environment is the best solution. To maintain high fluid temperatures and reduce heat loss to the environment, the conventional idea of a high value insulation like pipe-in-pipe with a vacuum annulus to avoid heat loss to the sensitive Arctic surroundings may seem to be a good solution, but it may not be the optimal solution. This paper discusses a hypothetical scenario (based on field cases) of a multiphase pipeline design and highlights the associated flow assurance/operational risks.

scholarly journals Clinical Outcome of Spine Surgery Complicated by Accidental Dural Tears: Meta-Analysis of the Literature

2020 ◽  
pp. 219256822091487
Author(s):  
Zeiad A. F. Alshameeri ◽  
El-Nasri Ahmed ◽  
Vinay Jasani
Keyword(s):  
Back Pain ◽  
Clinical Outcome ◽  
Spinal Surgery ◽  
Short Form ◽  
Meta Analysis ◽  
Systemic Review ◽  
Time Interval ◽  
Time Intervals ◽  
Dural Tears ◽  
The Impact

Study Design: Systemic review and meta-analysis. Objectives: Several studies have reported the impact of accidental dural tears (DT) on the outcome of spinal surgery, some with conflicting results. Therefore, the aim of this study was to carry out a systemic review and meta-analysis of the literature to establish the overall clinical outcome of spinal surgery following accidental DT. Method: A systemic literature search was carried out. Postoperative improvement in Oswestry Disability Index (ODI), Short-Form 36 survey (SF36), leg pain visual analogue scale (VAS), and back pain VAS were compared between patients with and without DT at different time intervals. Results: Eleven studies were included in this meta-analysis. There was a slightly better improvement in ODI and leg VAS score (standardized mean difference of −0.06, 95% confidence interval [CI] −0.12 to −0.01, and −0.06, 95% CI −0.09 to −0.02, respectively) in patients without DT at 12 months postsurgery, but this effect was not demonstrated at any other time intervals up to 4 years. There were no differences in the overall SF36 (function) score at any time interval or back pain VAS at 12 months. Conclusion: Based on this study, accidental DT did not have an overall significant adverse impact on the short-term clinical outcome of spinal surgery. More studies are needed to address the long-term impact and other outcome measures including other immediate complications of DT.

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