Entrepreneurial Impact: The Role of MIT

Presents an analysis of firms founded by Massachusetts Institute of Technology (MIT) alumni -- revenues, employees, spending on marketing and research and development, and type of firm -- by state to quantify MIT's entrepreneurial impact

Carbon-13 nuclear magnetic resonance spectra and mechanism of bridge–terminal carbonyl exchange in di-µ-carbonyl-bis[carbonyl(η-cyclopentadienyl)iron](Fe–Fe)[{(η-C5H5)Fe(CO)2}2]; cd-di-µ-carbonyl-f-carbonyl-ae-di(η-cyclopentadienyl)-b-(triethyl -phosphite)di-iron(Fe–Fe)[(η-C5H5)2Fe2(CO)3P(OEt)3], and some related complexes

A mechanism involving carbonyl-bridge breaking, rotation about the Fe–Fe bond, and bridge reformation is shown to account qualitatively for changes in the carbonyl region of the 13C n.m.r spectrum of the complex [(cp)(OC)[graphic omitted]e(cp){P(OEt)3}] and quantitatively for [(cp)(OC)[graphic omitted]e(CO)(cp)](cp =η-cyclopentadienyl).The activation energy for this process, 49.0 ± 4 kJ mol^–1(11.7 ± 1 kcal mol^–1), is close to that reported for cis–trans-isomerization of the cp groups, in accord with this mechanism. Variable-temperature 13C n.m.r. spectra of the complexes [(cp)(OC)[graphic omitted]u(CO)(cp)] and [(cp)(OC)[graphic omitted]i(cp)] are also reported

Hegemony, rebellion and history: Flodoard's Historia Remensis ecclesiae in Ottonian perspective

This article considers the growth of Ottonian hegemony through a close examination of Flodoard's Historia Remensis ecclesiae. Specifically, it scrutinises Flodoard's laconic account of a property dispute between the church of Rheims and Conrad the Red, Otto the Great's powerful duke of Lotharingia. Reading Flodoard's testimony alongside diplomatic evidence and Ottonian narratives, this study argues that the controversy was a factor in Conrad's rebellion against Otto in 953. Both the central role of Rheims' property in an Ottonian political conflict and Flodoard's silence on numerous aspects of the affair reveal that the church was deeply enmeshed in Ottonian politics. The Historia therefore offers an unrecognised angle on the expansion of Ottonian power, while further investigation of its content suggests that this emergent hegemony may indeed have been welcomed by Flodoard and his superiors at Rheims

Ecological determinants of depth zonation in reef-building corals

Natural gradients in altitude, depth or latitude capture systematic variation in environmental variables that can be exploited to test hypotheses on the role of various processes in generating and maintaining patterns of biodiversity. The depth zonation of reef-building corals is one such pattern, where species rich assemblages vary across a small spatial scale that includes rapid and predictable changes in key environmental variables, such as light. These attributes allow a strong test of general hypotheses predicting biodiversity patterns, free from many of the confounding factors found in terrestrial habitats. Here, I first develop a novel method of data collection, referred to as the modified Point-Count Transect method, which is derived from avian survey methods. This approach avoids many of the pitfalls of previous sampling approaches, such as inconsistent sampling effort, poor detection of rare species, and limited sampling coverage of the gradient. I then utilise this methodology to assemble a dataset of 9,576 coral colonies representing over 300 corals species, on six reefs in three positions within Kimbe Bay, PNG to 1) test the validity of the Species Energy theory and the Mid-Domain Effect; two preeminent predictive theories of species richness gradients 2) identify the reef-scale community assembly processes which maintain the depth-diversity pattern and 3) quantify how individual species abundances vary over depth. I found that species richness is not consistent with the predictions of either theory, and instead shows a left-skewed hump consistent with results from terrestrial habitats. Examination of species turnover suggested that the hump-shaped pattern is maintained by large-scale processes acting on the regional species pool, rather than differential levels of reef-scale processes, such as competition and environmental filtering. These results demonstrate that the hump-shaped pattern is not an artefact of scale or sampling design. Finally, species-specific abundance distributions across depth revealed species' depth use to be far more specialized than previously thought, demonstrating how commonly used metrics such as depth range, are very poor descriptions of how species use this domain. In conclusion, many of the preconceptions on the patterns and processes behind the depth zonation of corals on reefs are demonstrably flawed, and should be re-examined using suitable data and analysis. Although there remains no generally applicable explanation for how the hump-shaped pattern is created and maintained, this thesis provides new ways to overcome obstacles to continued research and move the field forwards

Analysis of the Impact of Early Exhaust Valve Opening and Cylinder Deactivation on Aftertreatment Thermal Management and Efficiency for Compression Ignition Engines

In order to meet strict emissions regulations, engine manufacturers have implemented aftertreatment technologies which reduce the tailpipe emissions from diesel engines. The effectiveness of most of these systems is limited when exhaust temperatures are low (usually below 200°C to 250°C). This is a problem for extended low load operation, such as idling and during cold start. Use of variable valve actuation, including early exhaust valve opening (EEVO) and cylinder deactivation (CDA), has been proposed as a means to elevate exhaust temperatures. This thesis discusses a research effort focused on EEVO and CDA as potential enablers of exhaust gas temperature increase for aftertreatment thermal management. EEVO results in hotter exhaust gas, however, more fueling is needed to maintain brake power output. The first study outlines an analysis of the impact of EEVO on exhaust temperature (measured at the turbine outlet) and required fueling. An experimentally validated model is developed which relates fueling increase with EVO timing. This model is used to generate expressions for brake thermal efficiency and turbine out temperature as a function of EVO. Using these expressions the impact of EEVO is evaluated over the entire low-load operating space of the engine. Considering the earliest EVO studied, the model predicts an approximate 30°C to 100°C increase in turbine out temperature, which is sufficient to raise many low-load operating conditions to exhaust temperatures above 250°C. However, the analysis also predicts penalties in brake thermal efficiency as large as 5%. The second study focuses on the impact of 3-cylinder CDA on exhaust temperature and efficiency at both loaded and unloaded idle conditions. CDA at idle results in a reduction in air-to-fuel ratio, and heat transfer surface area. This enables an increase in exhaust temperature for aftertreatment thermal management, and an increase in efficiency via reduced pumping and heat transfer losses. At the loaded idle condition, deactivating 3 cylinders provides an increase in exhaust temperature from about 200°C (6-cylinders) to approximately 300°C (3-cylinders), with no fuel economy penalty. Additionally, at the unloaded condition, CDA provides an increase in exhaust temperature of about 20°C, from about 117°C to about 135°C, with a fuel consumption reduction of 15%-26%. The third study includes additional research motivating CDA as a thermal management strategy. Results of an experimental load sweep with CDA show an increase of about 5% to 7% BTE at low load (1.3 bar) with an increase in exhaust temperature from 166°C to about 245°C. By about 2.5 bar, there is no significant change in BTE, yet an exhaust temperature increase is observed from 215°C to about 340°C. At 6.4 bar, a reduction of about 10% to 15% BTE is observed with a temperature increase from 354°C to about 512°C. As noted above, these are desirable benefits during steady-state; however, when an engine transitions from low to higher load, more air is needed to accompany the additional fuel. During transient operation, the reduced air-fuel ratio as a result of CDA limits the rate at which the load can be increased, as well as the maximum load that can be achieved. In addition to demonstrating the benefits of CDA during steady state operation, this paper identifies challenges with respect to transient operation of CDA for engines incorporating conventional air handling systems - high pressure EGR and variable geometry turbocharging. The transient Federal Test Procedure (FTP) cycle requires a load transition from near zero load to about 6 bar BMEP within approximately one second. This study shows that at low speed (800 rpm), the test engine operating in CDA mode cannot meet the load transition required by the FTP without mode transitioning to conventional 6 cylinder operation. At a moderate speed consistent with highway cruise conditions (1200 rpm), the transient FTP heavy-duty cycle can be met only by increasing the higher load air-fuel ratio target from ∼18 to ∼21, which reduces the temperature benefit seen from CDA by ∼60°C (from 512°C to 450°C) and increases the NOx from 3.2 to 10.3 g/hp-hr. The load response required for the mid-range cycle cannot be met with CDA due to low air-fuel ratios causing large soot emissions, even when air-fuel ratio is increased to ∼23. The work presented here provides insight into the thermal management capabilities of EEVO and CDA. EEVO can significantly raise exhaust temperatures; however, this comes at a large efficiency penalty. CDA provides large exhaust temperature increase accompanied by fuel consumption benefits at low load. This thesis demonstrates the benefit of CDA, but illustrates that remaining challenges exist with enabling transient operation

A critical edition of the text of The Dispensary, 1699, by Sir Samuel Garth, 1661-1719

VOLUME ONE: Acknowledgements • Note on the illustrations • A list of Abbreviations Used • Introduction Part One. The Medical Background to the Poem • Introduction Part Two. The Man and the Poem • Notes on the Text of this Edition • The DispensaryVOLUME TWO: Textual Notes • Annotations to The Dispensary • Appendix A. Garth and the Epistles of Phalaris and the Wits versus Blackmore • Appendix B. Notes on Garth's key to The Dispensary and Pope's annotated copies of the poem, together with a representative key to erroneous identifications of characters contained in The Dispensary • Select Bibliography to the Introduction and Appendice

Basic grant in FY 1973

Issued as Annual program and expenditures report, Project no. L-70-50