Flash Point and Chemical Composition of Aviation Kerosene (Jet A)

The relationship between chemical composition, flash point, and ignition energy was examined for eight samples of aviation kerosene (Jet A) with flash points between 29°C (84°F) and 74°C (165°F). We report the results of liquid characterization by two different laboratories. We use the results of headspace gas chromatography carried out by Woodrow and Seiber to characterize the vapor composition at liquid mass loading fractions of 3 and 400 kg/m^3. The composition data were analyzed to obtain analytical representations of vapor pressure and average molar mass as a function of temperature for each flash point fuel. The relationship between composition and flash point is examined by using two prediction methods. The first method is based on the notion of a critical value of fuel-air mass ratio at the flammability limit. The second method is based on Le Chatelier's rule for flammability limits. Both methods show a reasonable correlation between measured and predicted flash point. The relationship between flash point and ignition temperature threshold at a fixed spark ignition energy was examined for four fuels. A linear correlation was obtained for an ignition energy of 0.3 J. The effect of fuel weathering was examined by determining the flashpoints of seven fuel samples obtained from flight tests. The flash point increased about 8°C for fuel that had been exposed to 5 take-off, cruise, and landing cycles

2-aminophenols containing electron-withdrawing groups from N-aryl hydroxylamines

Reaction of substituted N-aryl hydroxylamines with methanesulfonyl chloride, p-toluenesulfonyl chloride, or trifluoromethanesulfonic anhydride under basic conditions leads to the rearranged 2-aminophenols (45-94%). The overall reaction sequence can be performed using polymer-supported sulfonyl chloride resin allowing for the effective conversion of N-aryl hydroxylamines to the 2-aminophenols without the need for chromatography

The Hysteresis Loop

It is not proposed to introduce a new method for the determination of the hysteresis loop, but to introduce some advantageous modifications. The method is similar to the ring ballistic method outlined by Dr. R. A. Millikan. This method has the advantage over the old magnetometer method in that the lines of force are continuous through the iron. It cannot be used however if the iron is hard and causes any creeping

Evaluating Retirement Planning : The Proper Mix of Investments?

This decision-based case developed from primary sources utilizes disguised names, but actual data to afford students the opportunity to evaluate and suggest changes to a real retirement portfolio. Leon and Billie Reynolds have asked their niece, Stacie, to review their retirement planning. The couple has accumulated just over $1,000,000 in investments with Teachers Insurance Annuity Association (TIAA) and College Retirement Equities Fund (CREF). The case gives the couple’s net worth, current salaries, insights into their spending habits, target retirement ages, family situation, and current allocations of their retirement funds. The case asks students to apply his or her financial planning skills to review the adequacy of the couple’s retirement planning

A New Type of Photoelectric Colorimeter

A photoelectric colorimeter has been constructed which is capable of detecting small changes in the color of meat. With this apparatus it was possible to measure the variation in the color of meat as a function of the time of exposure to the air. The effects of temperature upon the color variation were also measured; and some data has been obtained showing the relation between the color and the grade of the meat

Comparison of transesophageal and intracardiac electrophysiologic studies in characterization of supraventricular tachycardia in pediatric patients

Objectives.This study sought to determine the accuracy of transesophageal electrophysiologic studies in diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients.Background.Transesophageal electrophysiologic studies are a relatively noninvasive means of characterizing supraventricular tachycardia. Although widely used, to our knowledge no data exist that directly compare information obtained from transesophageal electrophysiologic studies with that from intracardiac electrophysiologic studies.Methods.We reviewed the records of 57 pediatric patients undergoing both transesophageal and intracardiac electrophysiologic studies at our institution. The results of these studies were compared with respect to mechanism of tachycardia, localization of accessory atrioventricular (AV) connections (if present) and characterization of anterograde accessory connection conduction properties.Results.Tachycardia mechanisms were concordant in 56 of 57 patients: orthodromic reciprocating tachycardia in 43, antidromic reciprocating tachycardia in 1, both orthodromic and antidromic tachycardia in 2, AV node reentrant tachycardia in 5, atrial reentrant tachycardia in 4 and ectopic atrial tachycardia in 2. Of 29 patients with orthodromic reciprocating tachycardia using a concealed accessory connection, transesophageal study predicted the accessory connection site through changes induced by transient bundle branch block in 12. By the Bland-Altman method in 14 patients with pre-excitation, the anterograde accessory connection effective refractory period determined by transesophageal study compared favorably with that determined by intracardiac study (mean difference 5.0 ms, limits of agreement −55 and 65 ms).Conclusions.Transesophageal electrophysiologic studies are a highly accurate means of diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients

Impact of \u3cem\u3eMYH6\u3c/em\u3e Variants in Hypoplastic Left Heart Syndrome

Hypoplastic left heart syndrome (HLHS) is a clinically and anatomically severe form of congenital heart disease (CHD). Although prior studies suggest that HLHS has a complex genetic inheritance, its etiology remains largely unknown. The goal of this study was to characterize a risk gene in HLHS and its effect on HLHS etiology and outcome. We performed next-generation sequencing on a multigenerational family with a high prevalence of CHD/HLHS, identifying a rare variant in the α-myosin heavy chain (MYH6) gene. A case-control study of 190 unrelated HLHS subjects was then performed and compared with the 1000 Genomes Project. Damaging MYH6 variants, including novel, missense, in-frame deletion, premature stop, de novo, and compound heterozygous variants, were significantly enriched in HLHS cases (P \u3c 1 × 10−5). Clinical outcomes analysis showed reduced transplant-free survival in HLHS subjects with damaging MYH6 variants (P \u3c 1 × 10−2). Transcriptome and protein expression analyses with cardiac tissue revealed differential expression of cardiac contractility genes, notably upregulation of the β-myosin heavy chain (MYH7) gene in subjects with MYH6 variants (P \u3c 1 × 10−3). We subsequently used patient-specific induced pluripotent stem cells (iPSCs) to model HLHS in vitro. Early stages of in vitro cardiomyogenesis in iPSCs derived from two unrelated HLHS families mimicked the increased expression of MYH7 observed in vivo (P \u3c 1 × 10−2), while revealing defective cardiomyogenic differentiation. Rare, damaging variants in MYH6 are enriched in HLHS, affect molecular expression of contractility genes, and are predictive of poor outcome. These findings indicate that the etiology of MYH6-associated HLHS can be informed using iPSCs and suggest utility in future clinical applications

Asymmetrical marriages in Aboriginal Australia: an annotated bibliography

This bibliography lists a large but incomplete selection of materials that deal directly or indirectly with Australian systems of asymmetrical descent, marriage and kinship. These systems seem to be significantly different from bilaterally symmetrical Kariera and Aranda models that have dominated Australian Aboriginal anthropology for more than a century. Several key items listed below are doctoral dissertations that are difficult to locate, and most of the items have a mathematical orientation. The asymmetry that concerns me has been labeled in many ways. Minimally, if the asymmetry is simply a unidirectional horizontal flow of spouses in an endogamously closed society, it contrasts easily with the bidirectional flow in Kariera and Aranda systems and has been called a circulating connubium. In it a chain of siblings-in-law form a closed circle that links multiple descent lines by marriage, typically with mother's brother's daughter (MBD) but not with father's sister's daughter (FZD). Through the generations, a mechanical representation of these relationships assumes the appearance of a cylinder with horizontally stratified generations stacked on top of each other and spouses flowing in one direction. The terminological problem becomes more complex when we take into consideration the 14+ year mean age difference between wives and husbands (W<H) that seems to characterize many or most Australian Aboriginal societies. The resulting age bias in same-generation cross-cousin marriages is reflected in systematic differences in father-child and mother-child generation lengths, wife-husband age differences and age differences at first marriages for men and women. It lends its name to sibling-in-law chains that assume the appearance of age biased generations