364 research outputs found
Methyl Methacrylate from Methyl Acetylene via Carboxymethylation
Previous process designs and current world demand for methyl methacrylate (MMA) have necessitated the investigation of the feasibility of designing a new MMA production process. The most commonly used industrial process for MMA production is the acetone cyanohydrin (ACH) process, which has the disadvantage of using large quantities of hydrogen cyanice (HCN). HCN is both an environmental and a health hazard if not handled properly. The Shell Oil Company has developed a process where the use of HCN can be avoided. In this process, methyl acetylene (MA) is converted to MMA by reaction with high-pressure carbon monoxide gas and methanol over a palladium catalyst. We have therefore considered the construction of a plant capable of producing 100 MM lbs./yr. of MMA at a United States Gulf Coast location via the carboxymethylation of methyl acetylene.
The worldwide demand for the use of MMA in plastics, resins, extrusions compounds, chemical intermediates, etc. is well documented. To satisfy this demand, we have successfully designed a plant to produce 111 MM lbs./yr. of 99.9% pure MMA at full capacity. The subsequent economic analysis of this design showed a return on investment after the third year of production of 56.3% and an investor\u27s rate of return of 39.5%. Based on these returns, and on the environmental and safety advantages of this production method over others currently in use, we highly recommend the construction of this plant beginning in April 2000
Automation of Data Analysis in Formula 1
This paper explores economic solutions for Formula 1 racing companies who are interested in data visualization tools. The research was conducted on the current development of data gathering, data visualization, and data interpretation in Formula 1 racing. It was found that a large chunk of racing companies within the league needs an affordable, effective, and automated visualization tool for data interpretation. As data collection in Formula 1 arises, the need for faster and more powerful software increases. Racing companies profit off-brand exposure and the more a racing team wins, the more exposure they receive. The goal of the paper focuses on solving the issue of data visualization. It begins with the current state of Formula 1 and the background of the billion-dollar industry. Then, the criteria needed for an effective solution is discussed and is used to measure three different software solutions. The three solutions considered were Tableau, Power BI, and Python. Python earned the highest rating according to the criteria of process time, scalability, usability, customizable, and cost-effectiveness. As proof of concept, a demo was created using Python, specifically using the Python framework Dash, showing the simplicity and versatility of the software. Racing companies looking to save money should consider implementing Python into their data visualization to increase their odds of winning and rising in the rankings
The Coevality of Young Binary Systems
Multiple star systems are commonly assumed to form coevally; they thus
provide the anchor for most calibrations of stellar evolutionary models. In
this paper we study the binary population of the Taurus-Auriga association,
using the component positions in an HR diagram in order to quantify the
frequency and degree of coevality in young binary systems. After identifying
and rejecting the systems that are known to be affected by systematic errors
(due to further multiplicity or obscuration by circumstellar material), we find
that the relative binary ages, |Delta log(tau)|, have an overall dispersion of
sigma~0.40 dex. Random pairs of Taurus members are coeval only to within
sigma~0.58 dex, indicating that Taurus binaries are indeed more coeval than the
association as a whole. However, the distribution of |Delta log(tau)| suggests
two populations, with ~2/3 of the sample appearing coeval to within the errors
(sigma~0.16 dex) and the other ~1/3 distributed in an extended tail reaching
|Delta log(tau)|~0.4-0.9 dex. To explain the finding of a multi-peaked
distribution, we suggest that the tail of the differential age distribution
includes unrecognized hierarchical multiples, stars seen in scattered light, or
stars with disk contamination; additional followup is required to rule out or
correct for these explanations. The relative coevality of binary systems does
not depend significantly on the system mass, mass ratio, or separation. Indeed,
any pair of Taurus members wider than ~10' (~0.7 pc) shows the full age spread
of the association.Comment: 23 pages, 11 figures; accepted to Ap
The future of evapotranspiration : global requirements for ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources
The fate of the terrestrial biosphere is highly uncertain given recent and projected changes in climate. This is especially acute for impacts associated with changes in drought frequency and intensity on the distribution and timing of water availability. The development of effective adaptation strategies for these emerging threats to food and water security are compromised by limitations in our understanding of how natural and managed ecosystems are responding to changing hydrological and climatological regimes. This information gap is exacerbated by insufficient monitoring capabilities from local to global scales. Here, we describe how evapotranspiration (ET) represents the key variable in linking ecosystem functioning, carbon and climate feedbacks, agricultural management, and water resources, and highlight both the outstanding science and applications questions and the actions, especially from a space-based perspective, necessary to advance them
Using screen video capture software to aide and inform cognitive interviewing
Web-based surveys are a salient tool in the repertoire of social and behavioral scientists. The increase in web-based surveys is understandable considering the distinct advantages offered, including: (a) lower costs and reduced labor time, (b) ability to directly transfer data into statistical packages (reducing coding errors), (c) customization options enabling more attractive presentation, (d) ability to reduce respondent burden by embedding skip patterns, and (e) access to larger sample sizes in different geographic regions. It is important to note, however, that administering web-based surveys also introduces distinct sources of error (e.g., coverage, sampling and non-response). Regardless of format (e.g., paper-and-pencil or web-based), specific, prescribed steps must be followed when constructing an instrument in order to reduce survey error and lend credence to the data collected before subsequent analysis is performed. One of those crucial stages integral to the pretesting process is cognitive interviewing. Cognitive interviewing is a qualitative process, encompassing two main techniques: think aloud interviewing and verbal probing. Collectively, these two methods seek to (a) produce information on what the respondent is thinking while answering the questions, (b) the cognitive processes used to answer the questions, and (c) how the respondent answers the questions. The purpose of this article is to provide a practical guide outlining how Camtasia, a screen video capture software, can aide and inform the cognitive interview process
Unimodality Problems in Ehrhart Theory
Ehrhart theory is the study of sequences recording the number of integer
points in non-negative integral dilates of rational polytopes. For a given
lattice polytope, this sequence is encoded in a finite vector called the
Ehrhart -vector. Ehrhart -vectors have connections to many areas of
mathematics, including commutative algebra and enumerative combinatorics. In
this survey we discuss what is known about unimodality for Ehrhart
-vectors and highlight open questions and problems.Comment: Published in Recent Trends in Combinatorics, Beveridge, A., et al.
(eds), Springer, 2016, pp 687-711, doi 10.1007/978-3-319-24298-9_27. This
version updated October 2017 to correct an error in the original versio
Sedimentary iron cycling and the origin and preservation of magnetization in platform carbonate muds, Andros Island, Bahamas
BASILICA Trial: One-Year Outcomes of Transcatheter Electrosurgical Leaflet Laceration to Prevent TAVR Coronary Obstruction
Background: Coronary artery obstruction is a rare, devastating complication of transcatheter aortic valve replacement. Transcatheter electrosurgical aortic leaflet laceration (Bioprosthetic or Native Aortic Scallop Intentional Laceration to Prevent Iatrogenic Coronary Artery Obstruction [BASILICA]) is a novel technique to prevent coronary artery obstruction. We report the 1-year outcomes of the BASILICA trial. Primary end points of 30-day success and safety have been reported previously.
Methods: The BASILICA trial was a prospective, multicenter, single-arm safety and feasibility study. Subjects with severe native or bioprosthetic aortic valve disease at high or extreme risk for surgery, and high risk of coronary artery obstruction, were included. End points at 1 year included death, stroke, and myocardial infarction. Source data was independently verified and end points independently adjudicated.
Results: Thirty subjects were enrolled between February 2018 and July 2018. At 30 days, BASILICA was successful in 28 subjects (93.3%), there were 3 strokes (10%), including 1 disabling stroke (3.3%), 1 death (3.3%), and 1 periprocedural myocardial infarction (3.3%). Between 30 days and 1 year, there were no additional strokes, no myocardial infarction, and 2 deaths (10% 1-year mortality). No subject needed repeat intervention for aortic valve or coronary disease. Two subjects had infective endocarditis (6.7%), but neither was isolated to the aortic valve. There were no hospital admissions for heart failure. Fourteen (46.7%) subjects required repeat hospital admission for other causes. Aortic valve gradients on echocardiography, New York Heart Association functional class, and Kansas City Cardiomyopathy Questionnaire scores improved from baseline to 30 days and were maintained at 1 year.
Conclusions: In these subjects with multiple comorbidities and restrictive anatomy that underwent transcatheter aortic valve replacement, there was no late stroke, myocardial infarction, or death related to BASILICA. Mitigation of coronary obstruction remained intact at 1 year and was not related to recurrent readmission. These results are reassuring for patients and physicians who wish to avoid the long-term complications related to snorkel stenting
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