A polarized, twisted, ethylene: structure of methyl 2-(1,3-dimethyl-2-imidazolidinylidene)-3-oxobutyrate dihydrate, C10H16N2O3.2H2O

Mr = 248, monoclinic, P21/n, a = 12.028 (2), b=7.168(2), c= 15.187(5)A, fl=91.88(2) °, Z= 4, V= 1308.6,~3, Din= 1.26, Dx= 1.263 Mgm -3, 2 (Cu Ka) = 1.5418 .A, g = 0.86 mm -1, F(000) = 536, T= 293 K. Final R = 5.6% for 2120 observed reflexions. Owing to the push-pull effect, the C=C bond distance is as long as 1.464 (2)/k with the twist angle about the bond 62.6.

Effect of an Ethylene Absorbent on Quality of Tomato Slices

Ethylene production is stimulated during the slicing of fresh cut tomato slices. Experiments were conducted to investigate whether the inclusion of ethylene absorbents in packaging affects the quality of tomato slices cv. Revolution during storage at 5OC. ‘Pink’ maturity stage tomatoes were cut into 7mm thick slices and vertically stacked in closed glass containers for 12 days with or without Purafil® to remove ethylene. The ethylene removal treatment resulted in reduced ethylene, less CO2 accumulation, and firmer slices.

Volumetric behavior of ethylene and ethylene-hydrogen mixtures

A Burnett apparatus deslgned and fabrlcated was used to collect volumetric data for ethylene and ethylene-hydrogen mixtures. Measurements were made In the temperature range 298.15-423.15 K at Intervals of 25 K and In the pressure range 0.3-7.0 MPa. Vlrlal coefflclents derlved from the compresslblllty data are tabulated. The data are fltted to different equations of state.

An Analysis of a Boundary Layer Diffusion Flame Over a Porous Flat Plate in a Confined Flow

A numerical analysis of the gas dynamic structure of a two-dimensional laminar boundary layer diffusion flame over a porous flat plate in a confined flow is made on the basis of the familiar boundary layer and flame sheet approximations neglecting buoyancy effects. The governing equations of aerothermochemistry with the appropriate boundary conditions are solved using the Patankar-Spalding method. The analysis predicts the flame shape, profiles of temperature, concentrations of variousspecies, and the density of the mixture across the boundary layer. In addition, it also predicts the pressure gradient in the flow direction arising from the confinement ofthe flow and the consequent velocity overshoot near the flame surface. The results of thecomputation performed for an n-pentane-air system are compared with experimental data andthe agreement is found to be satisfactory.

Soldiers with Flame Thrower Military; World War I

World War I Album II

Mechanistic studies on polymer flame retardancy Effect of Tribromoaniline

Abstract is not available.

Crystal Structure, Ultraviolet Spectrum, and Electronic Structure of a Strongly Twisted Push-Pull Ethylene, approaching an Amidinium-Vinylogous Dithioate Zwitterion

The crystal structure of 1,3-di benzyl -2 - (4,4-dimet hyl- 2,5- bist hioxocyclo hexylidene) imidazolidine (2) shows a twist of 80.8(5)' about the inter-ring bond, which has a length of 1.482(6) A. The near orthogonality of the donor and acceptor parts of this formal push-pull ethylene makes the structure approach that of a zwitterion, as evidenced by bond lengths indicating strong electron delocalization. The acceptor part approaches a vinylogous dithioate structure, the donor part an amidinium system. The U.V. spectrum shows an n + R and a R + R transition, at 51 1 and 41 7.5 nm, respectively; according to CNDO/S calculations these are located entirely in the [S-C-C-C-SI- part. Two bands at shorter wavelength are ascribed to transitions from combinations of the lone-pair orbitals on the sulphur atoms to a n* orbital in the [N-C-N] + part; this is facilitated by the near perpendicularity of the two parts of the molecule.

nvestigations on the Stability and Extinction of a Laminar Diffusion Flame Over a Porous Flat Plate

The limits of stability and extinction of a laminar diffusion flame have been experimentally studied in a two-dimensional laminar boundary layer over a porous flat plate through which n-pentane vapour was uniformly injected. The stability and extinction boundaries are mapped on a plot of free stream oxidant velocity versus fuel injection velocity. Effects of free stream temperature and of dilution of fuel and oxidant on these boundaries have been examined. The results show that there exists a limiting oxidant flux beyond which the diffusion flame cannot be sustained. This limiting oxidant flux has been found to depend_on the free stream oxygen concentration, fuel concentration and injection'velocity of the fuel.

Boronia heterophylla vase life is influenced more by ethylene than by bacterial numbers or vase solution pH

Bacterial proliferation in both vase solutions and in cut flower stems has been implicated in reducing the vase life of numerous genera. Boronia heterophylla F. Muell. (Red Boronia) vase life was assessed at two stages of floral maturity for nine vase solution treatments covering a pH range of 2.5-5.7. Vase life for advanced harvest maturity stems ranged from 4.2 d in 10 mM citric acid + 50 mg L-1 chlorine (pH 2.5) to 12.9 d after STS pulsing (pH 5.7). For normal harvest maturity stems, the corresponding range was 5.8-19.0 d, respectively. Vase solutions containing 50 mg L-1 chlorine biocide resulted in decreased longevity. In contrast, pulsing with the ethylene-binding inhibitor, STS, significantly increased vase life. The number of bacteria in the vase solutions after 11 d was determined in stems of advanced maturity. The solution with the greatest number of bacteria, 4.0 x 10(10) cfu mL(-1), was water used after STS pulsing and in which the flowers lasted longest. Vase solution bacteria were enumerated on days 0,3, 6, 9 and 12 of the vase period with stems of normal harvest maturity. There was no relationship between vase life and vase solution bacterial numbers ((R) over bar (2) = 0.000). Moreover, there was a negative relationship between numbers of bacteria in basal 0-5 cm stem segments and vase life. As no correlations were evident between longevity and either the pH or vase solution bacterial numbers, B. heterophylla vase life was evidently limited principally by ethylene action. (C) 2013 Elsevier B.V. All rights reserved.

Aminopyridinato Complexes as Possible Alternatives for Metallocenes in Ethylene Polymerization

Polyethylene is the most widely used synthetic polymer in the world. Most polyethylene is made with Ziegler-Natta catalysts. Polyethylenes for special applications are made with metallocenes, which are nowadays heavily patented. It is laborious therefore, to develop new metallocenes. The aim of this work was to investigate the feasibility of replacing the cyclopentadienyl ligands of metallocenes by aminopyridinato ligands without losing the good properties of the metallocenes, such as high activity and formation of linear polymer. The subject was approached by studying what kind of catalysts the metallocenes are and how they catalyze polyethylene. The polymerization behavior of metallocenes was examined by synthesizing a piperazino substituted indenyl zirconocene catalyst and comparing its polymerization data with that of the indenyl zirconocene catalyst. On the basis of their isolobality, it was thought that aminopyridinato ligands might replace cyclopentadienyl ligands. It was presumed that the polymerization mechanism and the active center in ethylene polymerization would be similar for aminopyridinato and metallocene catalysts. Titanium aminopyridinato complexes were prepared and their structures determined to clarify the relationship between structure of the catalyst precursor and polymerization results. The ethylene polymerization results for titanium 2-phenylaminopyridinato catalysts and titanocene catalysts were compared.

Controlled release of ethylene gas from the ethylene-α-cyclodextrin inclusion complex powder with deliquescent salts

Deliquescent calcium chloride (CaCl2) and magnesium chloride (MgCl2) were investigated for their practical application to release ethylene gas from an ethylene-α-cyclodextrin inclusion complexes (CD IC) powder at relative humidities (RHs) between 11.2 and 93.6 % at 18 °C. The IC powder and deliquescent salts were mixed at a ratio of 1:5, respectively. CaCl2 and MgCl2 started to deliquesce at 32.7 % RH. The IC powder dissolved in the concentrated salt solutions to release ethylene gas. Increasing the RH accelerated the release rate. Maximum release of ethylene gas was achieved after 24 h at 75.5 and 93.6 % RH for both IC powder-deliquescent salts mixture. The deliquescent salts proved to be a simple option for releasing ethylene gas from the IC powder.

Uses of an innovative ethylene-α-cyclodextrin inclusion complex powder for ripening of mango fruit

A novel ethylene-α-cyclodextrin (α-CD) inclusion complex (IC) powder was investigated to ripen Calypso mango fruit. Modulated release of ethylene gas from the IC powder was achieved by admixture with deliquescent salt CaCl2 at RHs of 75.5% and 93.6%. The IC powder was tested in the laboratory and for in-transit ripening of mango fruit over two seasons. In the laboratory experiment, ethylene gas started to release from the IC powder in 2 h and complete release was achieved in 24 h. Assessments of fruit colour and firmness showed that encapsulated ethylene and commercial grade ethylene from pressurised cylinder similarly shortened the ripening time to 9–10 days (after harvest) for treated fruit as compared with 15 days for untreated mango. Mango fruit treated in both ways with ethylene showed more uniform ripening than the control. For the in-transit ripening using the IC powder, ethylene was found to be between 4.9 and 10.5 μL L−1 in the headspace of the truck containers over 48 h. Mango fruit from the treated containers shortened the ripening time by 3–6 days as compared to the untreated control fruit. Thus, the safe and convenient IC powder has demonstrated promise for in-transit fruit ripening.