430 research outputs found
Advantages of the recursive operability analysis in updating the risk assessment
With the introduction of new regulations and sustainable technologies, revamping and upgrading already existing chemical plants is nowadays an important element in the framework of process engineering. Such important modifications must come along in parallel improvement of process safety. In this sense, risk assessment is a tool that should be versatile and easy to update by definition. However, even the most common methods currently used for accidental scenarios identification and risk assessment estimation (such as HazOp) may prove to be very time-consuming when discussing about safety from process modifications. The availability of a reliable and easy-to-update tool for safety engineering is crucial for process industries. In this work, we compare a risk analysis on a chemical plant subject of modifications performed with two different tools: HazOp and FTA vs Recursive Operability Analysis (ROA) and FTA. Both techniques have been applied to a tank dedicated to dust mixing that was subject of process modifications. Both methods come to the same conclusions, highlighting new failures and process criticalities, associated with the introduction of flow alarms and interlocks in case of excessive depressurizing. It is shown that the Recursive Operability Analysis, with its cause-consequence structure tied with process variable interactions, is much more effective in a risk assessment update
Frequency warping compressive sensing for structural monitoring of aircraft wing
This work focuses on an ultrasonic guided wave structural health monitoring (SHM) system development for aircraft wing inspection. The performed work simulate small, low-cost and light-weight piezoelectric discs bonded to various parts of the aircraft wing, in a form of relatively sparse arrays, for cracks and corrosion monitoring. The piezoelectric discs take turns generating and receiving ultrasonic guided waves. The development of an in situ health monitoring system that can inspect large areas and communicate remotely to the inspector is highly computational demanding due to both the huge number of Piezoelectric sensors needed and the high sampling frequency. To address this problem, a general approach for low rate sampling is developed. Compressive Sensing (CS) has emerged as a potentially viable technique for the efficient acquisition that exploits the sparse representation of dispersive ultrasonic guided waves in the frequency warped basis. The framework is applied to lower the sampling frequency and to enhance defect localization performances of Lamb wave inspection systems. The approach is based on the inverse Warped Frequency Transform (WFT) as the sparsifying basis for the Compressive Sensing acquisition and to compensate the dispersive behaviour of Lamb waves. As a result, an automatic detection procedure to locate defect-induced reflections was demonstrated and successfully tested on simulated Lamb waves propagating in an aluminum wing specimen using PZFlex software. The proposed method is suitable for defect detection and can be easily implemented for real application to structural health monitoring
On the asymptotic formula for Goldbach numbers in short intervals
Let
, \Sing(k) = 2
\prod\limits_{p>2}\left(1-\frac{1}{(p-1)^2}\right) \prod\limits_{\substack{
p\mid k\\ p>2 }} \left(\frac{p-1}{p-2}\right) if is even and \Sing(k)
=0 if is odd. It is known that R(k) \sim k\Sing(k) as
for almost all and that \sum_{k\in [n,n+H)}R(k) \sim
\sum_{k\in [n,n+H)} k\Sing(k) \quad\hbox{for} \quad n\to \infty \eqno{(1)}
uniformly for . Here we prove, assuming
and , that (1) holds for
almost all
Arthroscopic-guided balloon tibioplasty in schatzker iii tibial plateau fracture
Purpose The study aims to present the results at a mean 28-months follow-up of arthroscopic-guided balloon tibioplasty and to spot some technical tricks and some practice using tools and materials. Methods The study relates to six patients with tibial plateau fractures type Schatzker III with tibial plateau depression more than 4 mm at preoperative computed tomography scan (CT-scan). The follow-up period ranged from 22 to 33 months, with a mean of 28 months. No patients were lost to follow-up. The patients were evaluated clinically using the Rasmussen score system and Lysholm score systems at 6 to 12 and 24 months, postoperatively. Radiographic evaluations (standard X-rays) were done preoperatively at 1, 3, and 12 months postoperatively while a CT-scan with 3D reconstruction was performed preoperatively, at the first day and 6 months, postoperatively. Results The mean Rasmussen clinical score at 6 months postoperatively was 26.3 while at 1-year postoperatively the mean Rasmussen clinical score was 28.33. At 2-year postoperatively the mean Rasmussen clinical score was 28.83. Statistically significant difference was found in 6-months and 2-years results (p < 0.05). CT-scan achieved the first postoperative day showed the recovery of approximately 70% of the area of the interested tibial plateau, restoring of the joint surface without articular bone free fragments. Conclusion The described surgical procedure, if correctly performed with proper indications (Schatzker III), respect the principles mentioned above and the clinical and radiological results confirm our purpose. Level of Evidence This is a therapeutic case series, level IV study
Towards personalized medicine: Non-coding rnas and endometrial cancer
Endometrial cancer (EC) is the most frequent female cancer associated with excellent prognosis if diagnosed at an early stage. The risk factors on which clinical staging is based are constantly updated and genetic and epigenetic characteristics have recently been emerging as prognostic markers. The evidence shows that non-coding RNAs (ncRNAs) play a fundamental role in various biological processes associated with the pathogenesis of EC and many of them also have a prognosis prediction function, of remarkable importance in defining the therapeutic and surveillance path of EC patients. Personalized medicine focuses on the continuous updating of risk factors that are identifiable early during the EC staging to tailor treatments to patients. This review aims to show a summary of the current classification systems and to encourage the integration of various risk factors, introducing the prognostic role of non-coding RNAs, to avoid aggressive therapies where not necessary and to treat and strictly monitor subjects at greater risk of relapse
Non-coding RNAs as prognostic markers for endometrial cancer
Endometrial cancer (EC) has been classified over the years, for prognostic and therapeutic purposes. In recent years, classification systems have been emerging not only based on EC clinical and pathological characteristics but also on its genetic and epigenetic features. Noncoding RNAs (ncRNAs) are emerging as promising markers in several cancer types, including EC, for which their prognostic value is currently under investigation and will likely integrate the present prognostic tools based on protein coding genes. This review aims to underline the importance of the genetic and epigenetic events in the EC tumorigenesis, by expounding upon the prognostic role of ncRNAs
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Sleep hours and quality before and after baby: Inequalities by gender and partnership
While prior studies have examined sleep across the lifecourse, few studies have investigated sleep around the birth of a child, one of the most important events to cause sleep deprivation. This study investigates changes in sleep hours and quality, paying attention to differences by gender and partnership status. Using the UK Household Longitudinal Study, we follow approximately 1,000 participants as they transition into parenthood in a three-year window. We use OLS and logistic regression to analyze changes in sleep hours and sleep quality. Results suggest that women’s sleep is reduced by an average of 0.7 hours (42 min) on becoming a mother. Whilst before parenthood women sleep more than men, after childbirth women and men sleep similar amounts. Cohabiting men experience a greater reduction in sleep by around 0.5 hours (30 min) than married men, to the level similar to women, suggesting that new cohabiting fathers may experience more sleep disturbances
Volcanic Risk Management: the Case of Mt. Etna 2006 Eruption
Mt. Etna volcano is located in a very populated area of eastern Sicily (Italy). Its
permanent degassing activity from summit craters and frequent eruptions impact
significantly on town habitations and cultivated areas. In the latest years Etna has
produced copious ash emission causing great losses to local economy and causing
serious hazards to national and international air traffic over Mediterranean area and
the often closure of Catania airport.
In July 2006 eruptive vents opened on the East and South flanks of the summit
craters showing irregular explosive and effusive activity lasting 6 months.
This eruption represented the opportunity to perform the pre-operative test of FP6
Eurorisk-Preview (Prevention, Information and Early Warning) project aimed to
develop tools for monitoring volcanoes.
The test was performed during two temporal phases: the first one of early-warning
was aimed to measure ground deformation and the second one during the crisis to
survey volcanic ash produced during the explosions.
The ground deformations were measured through the elaboration of SAR data.
Beside the geophysical objectives, the test was also important to check data
availability and efficiency of European Space Agency procedures. The pre-operative
test has been peculiar to understand and quantify the delivering time of the final
satellite products expected from the Volcanological Observatory in operative case.
The analysis of July 2005 - July 2006 SAR data showed a pre-eruptive inflation trend
in agreement with the ground network of GPS data. The magmatic source, that
produced the September - October activity, has been located about 2.7 km below the
summit craters.
During the crisis phase characterized by paroxysmal activity, the Italian Civil
Protection (DPC) in charge of airport closure in case of volcanic hazard, requested
the satellite volcanic ash product retrieved from the NASA-MODIS data. An
agreement between the industry Telespazio as direct broadcast of satellite data at
Matera station and INGV was signed in order to elaborate the data in near-real time.
The volcanic ash product provided information about: the presence of volcanic ash in
the air; the affected area; the volcanic plume dispersal direction, dimensions and
altitude and the volcanic ash loading.
The satellite products and the observations report have been successively inserted in
a web-interface. At the same time the observations report has been linked to the
DPC dedicated Web-GIS interface that allows in a short time the availability of
volcanic ash information to DPC in support to their decisions.Published77-811.10. TTC - Telerilevamentoope
Volcanic Risk Management: the Case of Mt. Etna 2006 Eruption
Mt. Etna volcano is located in a very populated area of eastern Sicily (Italy). Its
permanent degassing activity from summit craters and frequent eruptions impact
significantly on town habitations and cultivated areas. In the latest years Etna has
produced copious ash emission causing great losses to local economy and causing
serious hazards to national and international air traffic over Mediterranean area and
the often closure of Catania airport.
In July 2006 eruptive vents opened on the East and South flanks of the summit
craters showing irregular explosive and effusive activity lasting 6 months.
This eruption represented the opportunity to perform the pre-operative test of FP6
Eurorisk-Preview (Prevention, Information and Early Warning) project aimed to
develop tools for monitoring volcanoes.
The test was performed during two temporal phases: the first one of early-warning
was aimed to measure ground deformation and the second one during the crisis to
survey volcanic ash produced during the explosions.
The ground deformations were measured through the elaboration of SAR data.
Beside the geophysical objectives, the test was also important to check data
availability and efficiency of European Space Agency procedures. The pre-operative
test has been peculiar to understand and quantify the delivering time of the final
satellite products expected from the Volcanological Observatory in operative case.
The analysis of July 2005 - July 2006 SAR data showed a pre-eruptive inflation trend
in agreement with the ground network of GPS data. The magmatic source, that
produced the September - October activity, has been located about 2.7 km below the
summit craters.
During the crisis phase characterized by paroxysmal activity, the Italian Civil
Protection (DPC) in charge of airport closure in case of volcanic hazard, requested
the satellite volcanic ash product retrieved from the NASA-MODIS data. An
agreement between the industry Telespazio as direct broadcast of satellite data at
Matera station and INGV was signed in order to elaborate the data in near-real time.
The volcanic ash product provided information about: the presence of volcanic ash in
the air; the affected area; the volcanic plume dispersal direction, dimensions and
altitude and the volcanic ash loading.
The satellite products and the observations report have been successively inserted in
a web-interface. At the same time the observations report has been linked to the
DPC dedicated Web-GIS interface that allows in a short time the availability of
volcanic ash information to DPC in support to their decisions
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