Evaluation of Mechanical Deaeration Parameters for High Vacuum Canned Foods

In mechanical deaeration of sliced apples, pears and cut green beans, increasing fill temperatures or chamber vacuum enhanced product deaeration, whereas increasing dwell time under vacuum from 3 to 9 sec did not (p < 0.05). Product ability to resist explosion when subject to sudden vacuum varied with products, firmness and temperature. Control of fill temperature was necessary for proper removal of oxygen from the canned products.     

Filter cubes with built-in ultrabright light-emitting diodes as exchangeable excitation light sources in fluorescence microscopy

The use of ultrabright light‐emitting diodes as a potential substitute for conventional excitation light sources in fluorescence microscopy is demonstrated. We integrated ultrabright light‐emitting diodes in the filter block of a conventional fluorescence microscope together with a collimating Fresnel lens, a holographic diffuser and emission filters. This setup enabled convenient changes between different excitation light sources and resulted in high excitation efficiencies. Quantitative comparison of image intensities of test samples revealed that light‐emitting diodes yielded intensities in the range of a mercury arc lamp depending on the wavelength. The use of ultrabright light‐emitting diodes also enabled luminescence lifetime imaging without the need for image intensification.     

颜色空间的直观印象

尽管新技术让生活更美好,但新技术的复杂性也偶尔会使其在应用中遇到阻力。新技术的开发既要有创新又要直观,这对聪明的设计人员构成了挑战。在楼字技术和房间控制领域,     

Solid Phase Microextraction for Cheese Volatile Compound Analysis

Cheese headspace volatile compounds were extracted with solid-phase microextraction (SPME) fibers, coated with either polydimethylsiloxane or polyacrylate, and thermally desorbed in the injector port for gas chromatographic (GC) analysis. Results with polyacrylate-coated fibers were better than those with a polydimethylsiloxane fiber. Major cheese volatile components such as volatile fatty acids and 5-lactones were readily extracted by both SPME fibers, but minor components such as volatile sulfur compounds were not observed. SPME-GC patterns were distinctly different among cheese varieties, and characteristic volatile compounds could be identified using multivariate techniques.     

Comparative Distribution of Volatile Aliphatic Disulfides Derived from Fresh and Dehydrated Onions

SUMMARY— Gas chromatographic determination of the volatiles from fresh "Sunspice" onions revealed that the principal disulfide present is di-St-propyl, followed in descending, order of concentration by n-propyl allyl, methyl-n-propyl, methyl allyl, dimethyl, and diallyl. In dehydrated onions this order is markedly altered. Methyl-n-propyl is the principal disulfide, followed by dimethyl, methyl allyl, di-n-propyl, n-propyl allyl, and diallyl. Quantitative estimates of the disulfide content of 53 lots of fresh onions were made and compared with analyses of dehydrated onions from comparable lot numbers. Loss of measured volatiles averaged 98%, while loss of disulfides was greater than 89%. The relationship of disulfides to onion flavor and a pungency ranking system based on these analyses are discussed.     

A Fast Buckling Analysis of Statically Indeterminate Variable-Section Struts

The force method, together with the virtual work principle, is used on desktop computers for the buckling analysis of variable-section struts. The method is based on the direct integration of the internal-work integral. The method is applied to struts composed of a thicker midsection and of two thin endsections under axial load. Several different upper-end constraints are considered. Such struts are used in fusion technology and in the cryogenic industry as flexible supports. Analyses appropriate to the flexible support of the toroidal field coils and of the vacuum vessel for the Next European Torus (NET) Project for the Controlled Thermonuclear Fusion Research are shown as examples.