Balloon groups

Find a local hot-air balloon group, and discuss with group members how they use the gas laws to fly their balloons. The group may be willing to give a demonstration. Report your experience to the class. 

Helium, the first member of the group, was detected in the spectrum of the Sun in 1868. Because of its low density (7 that of air), helium is used in all kinds of balloons and in synthetic atmospheres to make breathing easier for people suffering from emphysema. 

Selective removal of the benzyl ether-protecting group without hydrogenolysis of the ketal C-O bonds was performed on Ra-Ni in EtOH.154 155 A solution of benzyloxy acetal in MeOH with 5% Pd/C was stirred at room temperature with a H2 pressure from a balloon until the reaction was complete (Scheme 4.30).156... 

The palladium-catalyzed Heck carbonylation reaction is a powerful means of generating amides, esters, and carboxylic acids from aryl halides or pseudohalides [28]. The development of rapid, reliable, and convenient procedures for the introduction of carbonyl groups is important for the development of high throughput chemistry in general and high-speed microwave-mediated chemistry in particular. Unfortunately, the traditional method of introducing carbon monoxide into a reaction mixture via a balloon or gas tube is not practical because of the special requirements of microwave synthesis. 

This laboratory investigation will help you conceptualize the size of an atom. You will experiment with a latex balloon containing a vanilla bean extract. Latex is a polymer, meaning that it is a large molecule (a group of atoms that act as a unit) that is made up of a repeating pattern of smaller molecules. The scent of the vanilla extract will allow you to trace the movement of its molecules through the walls of the solid latex balloon. 

Figure 4 Hypercholesterolemic rabbit carotid artery 30 days after balloon injury. Photomicrographs of Verhoff s tissue elastin staining of (A,C) full-size and (B,D) higher magnification sections from (A,B) control, (C,D) liposomal alendronate treated (3mg/kg intravenous, at the time of injury). Control animals were treated with buffer, free BP (alendronate), or empty liposomes and grouped as control (n — 20 arteries/group, P<0.05). Abbreviation BP, bisphosphonate.

Serruys PW, de Jaegere P, Kiemeneij F, et al., for the BENESTENT study group. A comparison of balloon-expandable stent implantation with balloon angioplasty in patients with coronary artery disease. N Engl J Med 1994 331 489 95. 

After the discovery of the Antarctic ozone hole" in 1985, atmospheric chemist Susan Solomon led the first expedition in 1986 specifically intended to make chemical measurements of the Antarctic atmosphere by using balloons and ground-based spectroscopy. The expedition discovered that ozone depletion occurred after polar sunrise and that the concentration of chemically active chlorine in the stratosphere was 100 times greater than had been predicted from gas-phase chemistry. Solomon s group identified chlorine as the culprit in ozone destruction and polar stratospheric clouds as the catalytic surface for the release of so much chlorine. 

Balloons -as catheters PROSTHETIC AND BIOMEDICAL DEVICES] (Vol 20) -use ofhelium [HELIUM GROUP - GASES] (Vol 13)... 

The Pauson-Khand reaction, promoted by (CO)3Mo(DMF)3, has been found to take place under very mild conditions in the absence of any promoter. High yields of the adducts were obtained in the cyclization of a wide variety of functionalized 1,6- and 1,7-enynes. Enynes bearing electron-withdrawing groups at the alkene terminus proved to be particularly good substrates.121 The exclusive formation of cyclopentenones was observed in the molybdenum hexacarbonyl (10 mol%)-catalysed Pauson-Khand reactions of 1,6-allenynes under 1 atm of CO (balloon) in excellent yields.122... 

Waksman R, Kosinski AS, Klein L, et al. Relation of lumen size to restenosis after percutaneous transluminal coronary balloon angioplasty. Lovastatin Restenosis Trial Group, Am J Cardiol 1996 78 221-224. 

Erbel R, Haude M, Hopp HW, et al. Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group. New Engl J Med 1998 339 1672-1678. 

This was a complex case, requiring a full and detailed investigation by members of technical, engineering, operations, and process safety groups. Investigators made numerous interviews and detailed observations. Inspectors found a 6-inch (150 mm) long and 4-inch (100 mm) wide hole on a ballooned section of a heater tube. Normally the tube had a 6.6 inch (168 mm) outside diameter, but it had swollen to about 8.0 inches (200 mm) in diameter at a point about 2.5 ft. (0.75 m) above the heater floor. 

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