A Nonclassical Dihydrogen Adduct of S = ½ Fe(I)

We have exploited the capacity of the “(SiP^(iPr)_3)Fe(I)” scaffold to accommodate additional axial ligands and characterized the mononuclear S = 1/2 H_2 adduct complex (SiP^(iPr)_3)Fe^I(H_2). EPR and ENDOR data, in the context of X-ray structural results, revealed that this complex provides a highly unusual example of an open-shell metal complex that binds dihydrogen as a ligand. The H2 ligand at 2 K dynamically reorients within the ligand-binding pocket, tunneling among the energy minima created by strong interactions with the three Fe–P bonds

Harmonization of Life Cycle Climate Performance (LCCP) Methodology

Life cycle climate performance (LCCP) is an evaluation method by which heating, ventilation, air conditioning and refrigeration (HVAC&R) systems can be evaluated for the global warming impact over the course of their complete life cycle. LCCP is more inclusive than previous metrics such as total equivalent warming impact (TEWI). It is calculated as the sum of direct and indirect emissions generated over the lifetime of the system “from cradle to graveâ€. Direct emissions include all effects from the release of refrigerants into the atmosphere during the lifetime of the system. This includes annual leakage and losses during the disposal of the unit. The indirect emissions include emissions from the manufacturing process, energy consumption, and disposal of the system. This paper proposes a standardized approach to the use of LCCP and traceable data sources for all aspects of the calculation. An equation is proposed that unifies the efforts of previous researchers. Data sources are recommended for average values for all LCCP inputs. A residential heat pump sample problem is presented illustrating the methodology. The heat pump is evaluated at five U.S. locations in different climate zones. An excel tool was developed for residential heat pumps using the proposed method. The primary factor in the LCCP calculation is the energy consumption of the system.

Visualization of Evaporatively Cooled Heat Exchanger Wetted Fin Area

At high ambient temperature, the air cooled HX capacity can be boosted by using evaporation of a water film applied directly on the heat exchanger surface in deluge, spray, or mist cooling mode. In order to accurately determine evaporatively cooled HX capacity, it is critical to know the portion of fin area wetted. However, wetting inherently is a highly non-uniform phenomenon dependent on the method of application, evaporation rate and air velocity. Furthermore, for typical optimized air cooled HXs the fin geometry is often complex and spacing narrow. This study presents a novel method to quantify HX wetted fin area through enhanced visualization in HX depth and sectional flow rate measurement. Flow maps for deluge and front spray cooling are presented at varying inlet air velocities and wetting water flow rates. This study confirms that a significant portion of HX remains dry which contributes to low experimentally obtained HX heat transfer rates, irrespective of wetting method even under moderate to high wetting water flow rates. Furthermore, it highlights the need for developing HX wetting technologies that ensure uniform wetting at lowest wetting flow rates

Experimental Investigation of Multi-Functional Variable Refrigerant Flow System

The VRF systems have a better flexibility in the controlling strategy and a wider range of capacity modulation. In this study, a multi-functional VRF (MFVRF) system which is capable of heat recovery operation and water heating was experimentally investigated. The MFVRF system could supply space cooling and heating simultaneously in multiple zones, as well as providing hot water. The system performance was experimentally measured and discussed. It was found that the partial load performance of the system was improved with hot water demand, which increase the daily performance factor (DPF) by 17%. Moreover, it was also found that the system performance was enhanced by the heat recovery operation which could increase the hourly performance factor (HPF) by reducing the pressure difference across the compressor

カンボジア南部天水稲作地域の農家が集約稲作農法（SRI)を採用するのはなぜか

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 小林 和彦, 東京大学教授 岡田 謙介, 東京大学教授 溝口 勝, 東京大学教授 山路 永司, 国立研究開発法人国際農林水産業研究センター専門員 鳥山 和伸University of Tokyo(東京大学

Silylation of Iron-Bound Carbon Monoxide Affords a Terminal Fe Carbyne

A series of monocarbonyl iron complexes in the formal oxidation states 0, +1, and +2 are accessible when supported by a tetradentate tris(phosphino)silyl ligand (SiP^(iPr)_3 = [Si(o-C_(6)H_(4)PiPr_(2))_3]−). X-ray diffraction (XRD) studies of these carbonyl complexes establish little geometrical change about the iron center as a function of oxidation state. It is possible to functionalize the terminal CO ligand of the most reduced carbonyl adduct by addition of SiMe_(3)^+ to afford a well-defined iron carbyne species, (SiP^(iPr)_3)Fe≡C—OSiMe_3. Single-crystal XRD data of this iron carbyne derivative reveal an unusually short Fe≡C—OSiMe_3 bond distance (1.671(2) Å) and a substantially elongated C−O distance (1.278(3) Å), consistent with Fe−C carbyne character. The overall trigonal bipyramidal geometry of (SiP^(iPr)_3)Fe≡C—OSiMe_3 compares well with that of the corresponding carbonyls, (SiP^(iPr)_3)Fe(CO)^−, (SiP^(iPr)_3)Fe(CO), and (SiP^(iPr)_3)Fe(CO)^+. Details regarding the electronic structure of the carbyne complex have been explored via the collection of comparative Mössbauer data for all of the complexes featured and also via DFT calculations. In sum, these data point to a strongly π-accepting Fischer-type carbyne ligand that confers stability to a low-valent iron(0) rather than high-valent iron(IV) center