6,086 research outputs found
Importance of understanding variable and transient energy demand in large multi-product industrial plants for process integration
There have been some news releases claiming that Professor Henle in Germany has found the chemical identity of UMF, and that in future chemical analysis will be used instead of assays of antibacterial activity to indicate the level of UMF in manuka honey. Both of these claims are misleading. Because the level of active substance in manuka honey is an unreliable indication of the level of antibacterial activity and can be very misleading, it is hard to see any commercial advantage for it to be used to indicate antibacterial activity other than if someone wanted to fool the consumer into thinking that the higher numbers are giving them a level of antibacterial activity that is far higher than they are really getting
Recommended from our members
Being Different Yet Feeling Similar: The Influence Of Demographic Composition And Organizational Culture On Work Processes And Outcomes
Drawing from self-categorization theory, we tested hypotheses on the effects of an organization's demographic composition and cultural emphasis on work processes and outcomes. Using an organizational simulation, we found that the extent to which an organization emphasized individualistic or collectivistic values interacted with demographic composition to influence social interaction, conflict, productivity, and perceptions of creativity among 258 MBA students. Our findings suggest that the purported benefits of demographic diversity are more likely to emerge in organizations that, through their culture, make organizational membership salient and encourage people to categorize one another as having the organization's interests in common, rather than those that emphasize individualism and distinctiveness among members.(.)Managemen
Development and application of a clothed thermoregulatory model
Mathematical models of human thermoregulation can be used to assess the
habitability of thermal environments prior to human exposure. Work continues to
improve the performance of these models to reduce concerns surrounding the accuracy
of their predictions. The aims of this thesis were to develop an existing
thermoregulatory model (LUT25-node model).
The developments made to the LUT25-node model, now enable it to predict the
thermal responses of heat acclimated subjects of differing size, while its clothing
model was improved to consider the addition and distribution of clothing properties.
Validations of these modifications, confirmed that predictions from the model were
improved.
The thesis also looks at practical applications of the LUT25-node model. This
included a modification to the model enabling backward modelling; predicting how
the thermal stress should be altered to achieve a desired limit of thermal strain.
Several hypothetical scenarios illustrated the practical applications of this
modification. In addition, the LUT25-node model was used to explain the initial drop
in deep body temperature at the onset of exercise. This investigation concluded that
the temperature drop is due to the return of cool blood to the body core from initially
cool working muscles.
Finally, the poor predictions of the LUT25-node model for cold exposures was
investigated. Previous investigators suspected that this was due to the limited number
of thermal layers in the body segments of the model. However, predictions from a
multi-layered LUT25-node model, developed with the finite volume software package
PHOENICS, suggest that increasing the number of thermal layers reduces the
accuracy of the model's predictions for cold exposures.
In conclusion, this thesis has contributed to the continued development of a human
thermoregulatory model and illustrated its practical benefits. It is recommended that
future work centres on addressing additional limitations of the LUT25-node model
identified in this study
The effect of isoprenaline on induction of tumours by methyl nitrosourea in the salivary and mammary glands of female wistar rats.
Pretreatment of rats with isoprenaline sulphate (IPR) stimulated DNA synthesis in both salivary and mammary gland tissues. Salivary gland tumours induced by N-methyl-N-nitrosourea (MNU) were observed for the first time in rats, but occurred only in IPR-pretreated animals given MNU during the period of IPR-stimulated DNA synthesis. The cumulative index of MNU-induced mammary tumours and the number of tumours per tumour-bearing rat were increased by IPR-pretreament only if the animals received MNU during the period of IPR-stimulated DNA synthesis
Positive regulation of meiotic DNA double-strand break formation by activation of the DNA damage checkpoint kinase Mec1(ATR)
During meiosis, formation and repair of programmed DNA double-strand breaks (DSBs) create genetic exchange between homologous chromosomes-a process that is critical for reductional meiotic chromosome segregation and the production of genetically diverse sexually reproducing populations. Meiotic DSB formation is a complex process, requiring numerous proteins, of which Spo11 is the evolutionarily conserved catalytic subunit. Precisely how Spo11 and its accessory proteins function or are regulated is unclear. Here, we use Saccharomyces cerevisiae to reveal that meiotic DSB formation is modulated by the Mec1(ATR) branch of the DNA damage signalling cascade, promoting DSB formation when Spo11-mediated catalysis is compromised. Activation of the positive feedback pathway correlates with the formation of single-stranded DNA (ssDNA) recombination intermediates and activation of the downstream kinase, Mek1. We show that the requirement for checkpoint activation can be rescued by prolonging meiotic prophase by deleting the NDT80 transcription factor, and that even transient prophase arrest caused by Ndt80 depletion is sufficient to restore meiotic spore viability in checkpoint mutants. Our observations are unexpected given recent reports that the complementary kinase pathway Tel1(ATM) acts to inhibit DSB formation. We propose that such antagonistic regulation of DSB formation by Mec1 and Tel1 creates a regulatory mechanism, where the absolute frequency of DSBs is maintained at a level optimal for genetic exchange and efficient chromosome segregation
Non-continuous and variable rate processes: Optimisation for energy use
The need to develop new and improved ways of reducing energy use and increasing energy intensity in industrial processes is currently a major issue in New Zealand. Little attention has been given to optimisation of non-continuous processes in the past, due to their complexity, yet they remain an essential and often energy intensive component of many industrial sites. Novel models based on pinch analysis that aid in minimising utility usage have been constructed here through the adaptation of proven continuous techniques. The knowledge has been integrated into a user friendly software package, and allows the optimisation of processes under variable operating rates and batch conditions. An example problem demonstrates the improvements in energy use that can be gained when using these techniques to analyse non-continuous data. A comparison with results achieved using a pseudo-continuous method show that the method described can provide simultaneous reductions in capital and operating costs
A derivative method for minimising total cost in heat exchanger networks through optimal area allocation
This paper presents a novel Cost Derivative Method (CDM) for finding the optimal area allocation for a defined Heat Exchanger Network (HEN) structure and stream data, without any stream splits to achieve minimum total cost. Using the Pinch Design Method (PDM) to determine the HEN structure, the approach attempts to add, remove and shift area to exchangers where economic benefits are returned. From the derivation of the method, it is found that the slope of the Ξ΅-NTU relationship for the specific heat exchanger type, in combination with the difference in exchanger inlet temperatures and the overall heat transfer coefficient, are critical to calculating the extra overall duty each incremental area element returns. The approach is able to account for differences in film coefficients, heat exchanger types, flow arrangements, exchanger cost functions, and utility pricing. Incorporated into the method is the newly defined βutility cost savings flow-onβ factor, ΞΈ, which evaluates downstream effects on utility use and cost that are caused by changing the area of one exchanger. To illustrate the method, the CDM is applied to the distillation example of Gundersen (2000). After applying the new CDM, the total annual cost was reduced by 7.1 % mainly due to 24 % less HEN area for similar heat recovery. Area reduction resulted from one exchanger having a minimum approach temperature (ΞTmin) of 7.7 Β°C while the other recovery exchangers had larger ΞTmin values. The optimum ΞTmin for the PDM was 12.5 Β°C. The CDM solution was found to give a comparable minimum total area and cost to two recently published programming HEN synthesis solutions for the same problem without requiring the increased network complexity through multiple stream splits
AXONAL TRANSPORT AND TURNOVER OF PROLINE- AND LEUCINE-LABELED PROTEIN IN THE GOLDFISH VISUAL SYSTEM
The suitability of radioactively labeled proline as a marker of axonally transported protein in the goldfish visual system is further investigated and compared with another amino acid, leucine, in double-label experiments. Intraocularly injected proline is incorporated into protein in the eye S times more efficiently than is leucine, while local labeling of brain protein from precursor which has left the eye and entered the blood, (observed in the ipsilateral optic tectum) is five- to eight-fold less from proline than from leucine. The difference is attributed to the superior transport of leucine, an essential amino acid, into the brain from the blood. Once in the brain, the apparent rates of incorporation of the two amino acids are similar. Proline- or leucine-labeled, axonally transported proteins have a longer apparent half-life in the brain than do proteins labeled from intracranial injection of the precursors. By either route, proline-labeled proteins have a longer apparent half-life than leucine-labeled proteins. It is proposed that proline, released from protein breakdown is reutilized to a greater extent than is leucine.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65647/1/j.1471-4159.1974.tb10757.x.pd
PHP15 COMPARISON OF MARKET EXCLUSIVITY OF PHARMACEUTICALS IN CANADA, THE UNITED STATES, THE UNITED KINGDOM AND FRANCE
A uniform analysis of HD209458b Spitzer/IRAC lightcurves with Gaussian process models
We present an analysis of Spitzer/IRAC primary transit and secondary eclipse
lightcurves measured for HD209458b, using Gaussian process models to
marginalise over the intrapixel sensitivity variations in the 3.6 micron and
4.5 micron channels and the ramp effect in the 5.8 micron and 8.0 micron
channels. The main advantage of this approach is that we can account for a
broad range of degeneracies between the planet signal and systematics without
actually having to specify a deterministic functional form for the latter. Our
results do not confirm a previous claim of water absorption in transmission.
Instead, our results are more consistent with a featureless transmission
spectrum, possibly due to a cloud deck obscuring molecular absorption bands.
For the emission data, our values are not consistent with the thermal inversion
in the dayside atmosphere that was originally inferred from these data.
Instead, we agree with another re-analysis of these same data, which concluded
a non-inverted atmosphere provides a better fit. We find that a solar-abundance
clear-atmosphere model without a thermal inversion underpredicts the measured
emission in the 4.5 micron channel, which may suggest the atmosphere is
depleted in carbon monoxide. An acceptable fit to the emission data can be
achieved by assuming that the planet radiates as an isothermal blackbody with a
temperature of K.Comment: 18 pages, 5 figures, 6 tables. Accepted by MNRA
- β¦