Theoretical and experimental study of thermal contact resistance in a vacuum environment Semiannual status report no. 8, Jun. - Dec. 1965

Thermal contact resistance in vacuum environment using model prediction

Molecular phylogenetics of Melastomataceae and Memecylaceae

Melastomataceae are among the most abundant and diversified groups of plants throughout the tropics, but their intrafamily relationships and morphological evolution are poorly understood. Here we report the results of parsimony and maximum likelihood (ML) analyses of cpDNA sequences from the rbcL and ndhF genes and the rpl16 intron, generated for eight outgroups (Crypteroniaceae, Alzateaceae, Rhynchocalycaceae, Oliniaceae, Penaeaceae, Myrtaceae, and Onagraceae) and 54 species of melastomes. The sample represents 42 of the family’s currently recognized ~150 genera, the 13 traditional tribes, and the three subfamilies, Astronioideae, Melastomatoideae, and Memecyloideae (= Memecylaceae DC.). Parsimony and ML yield congruent topologies that place Memecylaceae as sister to Melastomataceae. Pternandra, a Southeast Asian genus of 15 species of which five were sampled, is the firstbranching Melastomataceae. This placement has low bootstrap support (72%), but agrees with morphological treatments that placed Pternandra in Melastomatacaeae because of its acrodromal leaf venation, usually ranked as a tribe or subfamily. The interxylary phloem islands found in Memecylaceae and Pternandra, but not most other Melastomataceae, likely evolved in parallel because Pternandra resembles Melastomataceae in its other wood characters. A newly discovered plesiomorphic character in Pternandra, also present in Memecylaceae, is a fibrous anther endothecium. Higher Melastomataceae lack an endothecium as do the closest relatives of Melastomataceae and Memecylaceae. The next deepest split is between Astronieae, with anthers opening by slits, and all remaining Melastomataceae, which have anthers opening by pores. Within the latter, several generic groups, corresponding to traditional tribes, receive solid statistical support, but relationships among them, with one exception, are different from anything predicted on the basis of morphological data. Thus, Miconieae and Merianieae are sister groups, and both are sister to a trichotomy of Bertolonieae, Microlicieae + Melastomeae, and Dissochaeteae + Blakeeae. Sonerileae/Oxysporeae are nested within Dissochaeteae, Rhexieae within Melastomeae, and African and Asian Melastomeae within neotropical Melastomeae. These findings have profound implications for our understanding of melastome morphological evolution (and biogeography), implying, for example, that berries evolved from capsules minimally four times, stamen connectives went from dorsally enlarged to basal/ventrally enlarged, and loss of an endothecium preceded poricidal dehiscence

An Experimental Investigation of the Air-Side Convective Heat Transfer Coefficient on Wire and Tube Refrigerator Condenser Coils

This thesis presents the results of an experimental investigation of the convective airside heat transfer from wire and tube condensers. The ftrst law of thermodynamics is applied to the "refrigerant", water in this investigation, flowing through the tubes in order to determine the total heat loss from the condenser. The test section is 910 mm (36 in) wide by 300 mm (12 in) tall; thus the coil is tested in an essentially inftnite stream. During the course of the experiments, the influence of the free stream air velocity ranging from 0.15 rn/s to 2.0 rn/s (0.49 ftls to 6.56 ftls) is established. The angle of attack, n, was varied from - 40 degrees to 40 degrees with the air flow always normal to the tubes ('11= 1t/2) and varied from -20 degrees to 20 degrees with the air flow normal to the wires ('II = 0). A method for , calculating view factors and the radiation heat transfer for wire and tube condensers is derived. The effect of the length of the coil is measered at 0 and -5??angle of attack. In addition, the influence of the ftn efftciency on the heat transfer is investigated and accounted for in the deftnition of the heat transfer coefftcient. The heat transfer data in the inertia dominated regime (Richardson number less than 0.0013) are correlated assuming NUcoil = t(Re, n, 'II)' g( S: ) with the Reynolds number based on the wire diameter. The range of Reynolds numbers covered is 15.7 < Rew < 207.5. The ranges of coil geometric parameters (nondimensionlized by dividing by the wire diameter) covered in this study are: 3.022 < nondimensional tube diameter < 5.134, 18.84 < nondimensional tube spacing < 40.94,2.819 < nondimensional wire spacing < 4.427,53.80 < nondimensional tube length< 143.6, and 207.2 < nondimensional wire length < 500.2. The function is represented by tl(a)??Reh (a) for 'II = 0 and h(a).Rei4 (a) for'll=1t/2. Approximately 1700 tests were performed in this investigation using seven different coils. The ftnal correlation is capable of predicting the data with 2cr equal to 16.7% for Ri < 0.0013. A limited natural convection study is also presented.Air Conditioning and Refrigeration Center Project 4

Historical biogeography of Melastomataceae

Melastomataceae and Memecylaceae are pantropically distributed sister groups for which an ndhF gene phylogeny for 91 species in 59 genera is here linked with Eurasian and North American fossils in a molecular clock approach to biogeographical reconstruction. Nine species from the eight next-closest families are used to root phylogenetic trees obtained under maximum likelihood criteria. Melastomataceae comprise ∼3000 species in the neotropics, ∼1000 in tropical Asia, 240 in Africa, and 225 in Madagascar in 150-166 genera, and the taxa sampled come from throughout this geographic range. Based on fossils, ranges of closest relatives, tree topology, and calibrated molecular divergences, Melastomataceae initially diversified in Paloecene/Eocene times in tropical forest north of the Tethys. Their earliest (Eocene) fossils are from northeastern North America, and during the Oligocene and Miocene melastomes occurred in North America as well as throughout Eurasia. They also entered South America, with earliest (Oligocene) South American fossils representing Merianieae. One clade (Melastomeae) reached Africa from the neotropics 14-12 million years ago and from there spread to Madagascar, India, and Indochina. Basalmost Melastomataceae (Kibessieae, Astronieae) are species-poor lineages restricted to Southeast Asia. However, a more derived Asian clade (Sonerileae/Dissochaeteae) repeatedly reached Madagascar and Africa during the Miocene and Pliocene. Contradicting earlier hypotheses, the current distribution of Melastomataceae is thus best explained by Neogene long-distance dispersal, not Gondwana fragmentation

Program for computing partial pressures from residual gas analyzer data

A computer program for determining the partial pressures of various gases from residual-gas-analyzer data is given. The analysis of the ion currents of 18 m/e spectrometer peaks allows the determination of 12 gases simultaneously. Comparison is made to ion-gage readings along with certain other control information. The output data are presented in both tabular and graphical form

Transfer pricing: strategies, practices, and tax minimization

Using a survey of tax executives from multinational corporations, we document that some firms set their transfer pricing strategy to minimize tax payments, but more firms focus on tax compliance. We estimate that a firm focusing on minimizing taxes has a GAAP effective tax rate that is 6.6 percentage points lower and generates about $43 million more in tax savings, on average, than a firm focusing on tax compliance. Available COMPUSTAT data on sample firms confirm our survey‐based inferences. We also find that transfer pricing‐related tax savings are greater when higher foreign income, tax haven use, and R&D activities are combined with a tax minimization strategy. Finally, compliance‐focused firms report lower FIN 48 tax reserves than tax‐minimizing firms, consistent with the former group using less uncertain transfer pricing arrangements. Collectively, our study provides direct evidence that multinational firms have differing internal priorities for transfer pricing, and that these differences are strongly related to the taxes reported by these firms.First author draf