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101.
Gary Burgess 《Packaging Technology and Science》1999,12(2):75-80
Several styles of insulating packages were studied, ranging in size from 0.5 to 5 cubic feet and varying in construction from the ordinary expanded polystyrene cooler to various liner‐in‐box arrangements with and without aluminium foil surfaces. Ice‐melt tests were conducted to measure package insulating ability and the results were used to determine the thermal resistance (R‐value). The R‐value was then related to details connected with package construction including wall thickness, number of layers and number of foil surfaces through a simple equation so that it can be estimated for any construction. The system R‐value can then be used to estimate refrigerant requirements and temperature holding times for known shipping environments. Examples are included. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
102.
Single pellets (≈3 mm diameter) of high density polyethylene (HDPE) have been burned in an electrically heated bed of silica sand, fluidised by air or mixtures of N2 and O2 at atmospheric pressure. During the combustion of single pellets, measurements were made of the concentrations of CO and CO2 in the off-gas, enabling burnout-times to be derived. This was done for different temperatures (400–900 °C) in a bubbling fluidised bed and a range of masses for the HDPE pellets. In addition, the size of the sand, the fluidising velocity and the concentration of O2 in the fluidising gas were all varied. In a bed above 400 °C, a polymer pellet melted on entering the hot sand, which was wetted to form a small aggregate (or “blob” ∼5 mm in diameter) of sand particles held together by molten polymer. Next, the blob sank and volatilisation and thermal decomposition of the polymer produced hydrocarbon vapours, which burned mainly above the sand. It was deduced that there are actually three ranges of temperature, each with a different mechanism of combustion. With the bed in the high temperature regime at 640–900 °C, burnout was controlled by mass transfer of hydrocarbon vapour (deduced to have a mean composition of approximately (C2H4)5) away from such a blob of sand and molten polymer. When the bed was between 485 and 640 °C (the medium temperature regime), radiative heat transfer to a blob of polymer controlled burnout. At 400–485 °C (the low temperature region) the burnout-time was controlled by the volatilisation (gasification) of a polymer pellet to produce a combustible hydrocarbon vapour. The activation energy for this gasification was ∼58 kJ/mol. This is the same as that characterising the ignition delay, which was also measured. The measured rates of burning indicate an enthalpy of gasification of ≈450 J/g. The total yield of CO and CO2 was found to depend on the bed’s temperature and was low enough to indicate that soot, together with unburned hydrocarbons, can be important products from such a bed. 相似文献
103.
Ann?M.?McCauley Clain?A.?JonesEmail author Perry?R.?Miller Macdonald?H.?Burgess Catherine?A.?Zabinski 《Nutrient Cycling in Agroecosystems》2012,92(3):305-314
Crop-fallow systems dominate many semi-arid agricultural regions despite fallow’s negative effects on soil and water quality.
Annual legumes grown as a fallow-replacement crop, and terminated prior to maturity, can reduce these negative effects without
substantially decreasing plant available water for the subsequent crop. Interest in growing legume green manures (LGMs) in
synthetically-fertilized systems is increasing in the northern Great Plains of North America, partly due to the N-fixing capabilities
of legumes; however, little is known about the effects of planting and termination time on N fixation amounts in the region.
A 2-year field study was initiated in southwest Montana to determine the effects of planting time (spring or summer) and termination
time (e.g. flower or pod) on the amount of N fixed by field pea (Pisum sativum cv. Arvika) and lentil (Lens
culinaris cv. Richlea). Two methods, 15N natural abundance and N difference, were used to quantify N fixation, with wheat or in-crop weeds as reference plants. In
2009, N fixed by spring-planted lentil was higher by pod than flower (P = 0.03). Termination time did not affect the amount of N fixed by spring-planted pea, despite more biomass by pod than flower.
In 2010, both spring-planted crops fixed more N by pod than flower (P < 0.01) and more N was fixed by spring-planted than summer-planted crops (P < 0.01). These results should prove useful to growers interested in selecting management practices that optimize N fixation
of LGMs. 相似文献
104.
McDonnell MJ Rivas L Burgess CM Fanning S Duffy G 《International journal of food microbiology》2012,153(3):260-268
The antimic robial activities of caseicin A and B antimicrobial peptides (AMPs) were assessed against a selection of verocytotoxigenic Escherichia coli (VTEC) strains (n = 11), other bacterial pathogenic and spoilage bacteria (n = 7), using a model broth system. The ability of the AMPs to retain their antimicrobial activities against a strain of E. coli O157:H7 380-94 under various test conditions (pH, temperature, water activity, sodium chloride concentrations, inoculum size and the presence of competitive microflora) was assessed and the minimum inhibitory concentrations (MIC) and number of surviving E. coli O157:H7 calculated. The mean number of VTEC surviving after exposure to 2 mg/ml caseicin A and B was reduced by 4.96 and 4.19 log10 cfu/ml compared to the respective controls. The susceptibility of E. coli O157:H7 to the caseicin AMPs decreased as temperature, pH, water activity and inoculum size were reduced. The presence of sodium chloride (0.5-2.5%) did not affect the activity of caseicin A (p > 0.05), however it did inhibit the activity of caseicin B. The presence of a competitive microflora cocktail did not significantly (p > 0.05) affect the activities of the AMPs for the majority of the concentrations tested. Using a quantitative PCR assay, the levels of verotoxins (vt1 and vt2) expressed by E. coli O157:H7 following exposure to a sub-inhibitory concentration (0.5 mg/ml) of caseicin A showed that the verotoxin levels did not differ from the levels produced by the control cultures. The antimicrobial activity of caseicin A against E. coli O157:H7 was also tested in a model rumen system, however concentrations of ≥ 2 mg/ml did not significantly (p > 0.05) reduce E. coli O157:H7 numbers in the model system over a 24 h period. The application of caseicin AMPs in food and/or animal production may be valuable in combination with other antimicrobials although further research is required. 相似文献
105.
Carbon and complex nitrogen source selection for secondary metabolite cultivation at the pilot scale
Junker B Mann Z Burgess B King J Greasham R 《Journal of Bioscience and Bioengineering》2001,91(5):462-468
The fermentation of desmethyl-asterriquinone B-1, a diabetes target, by a Pseudomonasarias species was conducted at the 600-l scale using a revised complex medium containing yeast extract and soy hydrolysate. Oat flour and tomato paste were removed from this medium due to difficulties in sterilization. An initial cerelose charge of 40 g/l improved titer and reduced product degradation in the broth at cultivation conditions. An initial mannitol concentration of 65 g/l effectively avoided mid-cycle mannitol additions necessary for the 40 g/l mannitol concentration without the reduction in productivity seen at 90 g/l mannitol. These additions diluted the broth because of the low aqueous solubility of mannitol. Titers reached 3.0 g/l after 158 h with an optimized process, increasing two-fold from the original medium and operating conditions. Reproducible foaming occurred at the point of glucose exhaustion when the culture switched to mannitol consumption. Use of alternative carbon sources (glycerol, soybean oil, sorbitol in conjunction with cerelose) was not effective in attaining similar productivity and did not reduce the extent of foaming. In the case of fructose, the extent of foaming was markedly reduced but product formation was negligible. 相似文献
106.
Dr. Syed Muhammad Usama Dr. Zhengyang Jiang Kathryn Pflug Dr. Raquel Sitcheran Dr. Kevin Burgess 《ChemMedChem》2019,14(17):1575-1579
We hypothesized that conjugation of the near-infrared dye MHI-148 with the anti-leukemia drug dasatinib might produce a potential theranostic for glioblastoma. In fact, the conjugate was found to bind the kinases Src and Lyn, and to inhibit the viability of a glioblastoma cell line with significantly greater potency than dasatinib alone, MHI-148 alone, or a mixture of dasatinib and MHI-148 at the same concentration. It was also used to successfully image a subcutaneous glioblastoma tumor in vivo. 相似文献
107.
The total-system goals, CPU design goals, and modular design approach of the high-performance MC68332 microcontroller are described. The features of the system integration module, queued serial module, and standby RAM are summarized. The CPU and time processor modules are discussed in detail 相似文献
108.
A comparison of the boundary element and superposition methods 总被引:16,自引:0,他引:16
For some time now, the Boundary Integral Equation (BIE) Method or as it is alternately called the Boundary Element Method (BEM) has been hailed as the technique best suited to problems in elasticity and related fields, both for accuracy and efficiency. The authors demonstrate by example that this is not the case. A much simpler and more versatile technique, the Superposition Method (SUP), is introduced and is shown to outperform BEM in both areas. Followed by a discussion of the merits and drawbacks of each method, compact computer programs for both BEM and SUP and numerical results for nine different example problems are presented to support the authors' claim. 相似文献
109.
Gary Burgess 《Computers & Structures》1984,19(5-6):839-841
The choice of which fundamental singular solutions to use as basis functions in the so-called singularity method applied to elasticity appears to be restricted by boundary condition types and region geometry. In practice, only the point load solution is consistently reliable but even it fails in certain instances when the elastic body is not a convex region and almost always when the region is not simply connected. Fortunately, all multiply connected regions can be partitioned into simply-connected (although not always convex) ones. A method for doing this is presented along with examples of fundamental solutions which do not work in the singularity method. 相似文献
110.
MA Kemper HS Gao-Sheridan B Shen JL Duff GJ Tilley FA Armstrong BK Burgess 《Canadian Metallurgical Quarterly》1998,37(37):12829-12837
In clostridial-type ferredoxins, each of the two [4Fe-4S]2+/+ clusters receives three of its four ligands from a CysXXCysXXCys motif. Azotobacter vinelandii ferredoxin I (AvFdI) is a seven-iron ferredoxin that contains one [4Fe-4S]2+/+ cluster and one [3Fe-4S]+/0 cluster. During the evolution of the 7Fe azotobacter-type ferredoxins from the 8Fe clostridial-type ferredoxins, one of the two motifs present changed to a CysXXCysXXXXCys motif, resulting in the inability to form a 4Fe cluster and the appearance of a 3Fe cluster in that position. In a previous study, we were unsuccessful in using structure as a guide in designing a 4Fe cluster in the 3Fe cluster position of AvFdI. In this study, we have reversed part of the evolutionary process by deleting two residues between the second and third cysteines. UV/Vis, CD, and EPR spectroscopies and direct electrochemical studies of the purified protein reveal that this DeltaT14/DeltaD15 FdI variant is an 8Fe protein containing two [4Fe-4S]2+/+ clusters with reduction potentials of -466 and -612 mV versus SHE. Whole-cell EPR shows that the protein is present as an 8Fe protein in vivo. These data strongly suggest that it is the sequence motif rather than the exact sequence or the structure that is critical for the assembly of a 4Fe cluster in that region of the protein. The new oxygen-sensitive 4Fe cluster was converted in partial yield to a 3Fe cluster. In known ferredoxins and enzymes that contain reversibly interconvertible [4Fe-4S]2+/+ and [3Fe-4S]+/0 clusters, the 3Fe form always has a reduction potential ca. 200 mV more positive than the 4Fe cluster in the same position. In contrast, for DeltaT14/DeltaD15 FdI, the 3Fe and 4Fe clusters in the same location have extremely similar reduction potentials. 相似文献