Heat transfer coefficients of condensing vapors

Several experimental methods have been developed for the determination of the rate of heat transfer between a pure condensing organic vapor and a cold surface. The experimental results of the earliest method, the so-called embedded thermocouple approach, have not been in good agreement with heat transfer values predicted by the theoretical Nusselt equation, nor has good agreement been found among the individual data, The alternate method was an indirect approach developed by Wilson and was based on the effect of cooling watt r velocity. Wilson\u27s method provided values in close agreement with the values predicted by the Nussalt equation but was empirical in nature. nth methods have been subject to criticism. Chu, Flitcraft and Holeman developed and tested a modification of the Wilson method based on a rigorous theoretical analysis which postulated that the film coefficient was an inverse function of the heat transferred and weld be determined by graphical means. With a few exceptions, notably toluene, this technique has provided values in good agreement with the predicted theoretical coefficients. The purpose of this work was three-fold: to enlarge the span of opereting conditions investigated with particular reference to extension of the cooling water velocity range; to determine whether the modified Wilson method was applicable to n-propyl and n-amyl alcohol; and to investigate n-butyl alcohol which was previously tested and did not exhibit a variation of the film coefficient with the heat transferred. The experimental results of this investigation showed the values obtained for the three alcohols to be in conformance with the behavior expected by Chu and were in food agreement with the predicted values. The Chu method was also found to be applicable over the larger eater flow range tested. In addition, the extended range provided data that allowed more accurate charting of the graphical method. The inclusion of this data was instrumental in determining the variation of the heat transfer coefficient, ho, with q for the n-butyl alcohol where none was found previously. It is felt that a similar Investigation over the extended range of water flow would clarify the variation of h for toluene, the only presently know exception to Chu\u27s method

An empirical study on the factors conducive to productivity and their relative significance in improving efficiency and performance in the office environment

The research examined the area of lean office with the aim of identifying means through which office efficiency could be improved. The researcher conducted primary and secondary research into the topic of lean office. He researched relevant material in books, journals and websites and used a questionnaire to survey a representative sample of office staff in the West of Ireland. The primary research indicated that the lean office concept wasn’t widely used among the respondents’ companies. However, the respondents in general indicated a high level of satisfaction with the adequacy of office equipment, the layout of the office, safety levels in the office and with the levels of staff interaction. There were also high levels of satisfaction in relation to how the role of the respondents contributed to the overall results of the company. A majority of the respondents indicated that their companies measured productivity, had productivity targets and that their company had obtained at least one quality standard. However, in the matter of waste, a lesser majority indicated that forms and processes had been examined in their company with a view to eliminating such waste. Respondents gave examples of where waste occurred under the seven main areas of waste. The philosophy of lean wasn’t applied as commonly as the researcher expected but in general the results from the questionnaire indicated that efforts were being made to make the office as efficient as possible. As the drive to improve competitiveness increases, increasing efficiency in the office can’t be overlooked and the philosophy of lean can play an important role in achieving high levels of efficiency

Combined effects of time spent in physical activity, sedentary behaviors and sleep on obesity and cardio-metabolic health markers: a novel compositional data analysis approach

<div><p>The associations between time spent in sleep, sedentary behaviors (SB) and physical activity with health are usually studied without taking into account that time is finite during the day, so time spent in each of these behaviors are codependent. Therefore, little is known about the combined effect of time spent in sleep, SB and physical activity, that together constitute a composite whole, on obesity and cardio-metabolic health markers. Cross-sectional analysis of NHANES 2005–6 cycle on N = 1937 adults, was undertaken using a compositional analysis paradigm, which accounts for this intrinsic codependence. Time spent in SB, light intensity (LIPA) and moderate to vigorous activity (MVPA) was determined from accelerometry and combined with self-reported sleep time to obtain the 24 hour time budget composition. The distribution of time spent in sleep, SB, LIPA and MVPA is significantly associated with BMI, waist circumference, triglycerides, plasma glucose, plasma insulin (all p<0.001), and systolic (p<0.001) and diastolic blood pressure (p<0.003), but not HDL or LDL. Within the composition, the strongest positive effect is found for the proportion of time spent in MVPA. Strikingly, the effects of MVPA replacing another behavior and of MVPA being displaced by another behavior are asymmetric. For example, re-allocating 10 minutes of SB to MVPA was associated with a lower waist circumference by 0.001% but if 10 minutes of MVPA is displaced by SB this was associated with a 0.84% higher waist circumference. The proportion of time spent in LIPA and SB were detrimentally associated with obesity and cardiovascular disease markers, but the association with SB was stronger. For diabetes risk markers, replacing SB with LIPA was associated with more favorable outcomes. Time spent in MVPA is an important target for intervention and preventing transfer of time from LIPA to SB might lessen the negative effects of physical inactivity.</p></div

Modulation of Cardiac Performance by Motor Protein Gene Transfer

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75444/1/annals.1420.011.pd

UK Housing Market: Time Series Processes with Independent and Identically Distributed Residuals

The paper examines whether a univariate data generating process can be identified which explains the data by having residuals that are independent and identically distributed, as verified by the BDS test. The stationary first differenced natural log quarterly house price index is regressed, initially with a constant variance and then with a conditional variance. The only regression function that produces independent and identically distributed standardised residuals is a mean process based on a pure random walk format with Exponential GARCH in mean for the conditional variance. There is an indication of an asymmetric volatility feedback effect but higher frequency data is required to confirm this. There could be scope for forecasting the index but this is tempered by the reduction in the power of the BDS test if there is a non-linear conditional variance process

An exploration of heat tolerance in mice utilizing mRNA and microRNA expression analysis

Background Individuals who rapidly develop hyperthermia during heat exposure (heat-intolerant) are vulnerable to heat associated illness and injury. We recently reported that heat intolerant mice exhibit complex alterations in stress proteins in response to heat exposure. In the present study, we further explored the role of genes and molecular networks associated with heat tolerance in mice. Methodology Heat-induced physiological and biochemical changes were assessed to determine heat tolerance levels in mice. We performed RNA and microRNA expression profiling on mouse gastrocnemius muscle tissue samples to determine novel biological pathways associated with heat tolerance. Principal Findings Mice (n = 18) were assigned to heat-tolerant (TOL) and heat-intolerant (INT) groups based on peak core temperatures during heat exposures. This was followed by biochemical assessments (Hsp40, Hsp72, Hsp90 and Hsf1 protein levels). Microarray analysis identified a total of 3,081 mRNA transcripts that were significantly misregulated in INT compared to TOL mice (p\u3c0.05). Among them, Hspa1a, Dnajb1 and Hspb7 were differentially expressed by more than two-fold under these conditions. Furthermore, we identified 61 distinct microRNA (miRNA) sequences significantly associated with TOL compared to INT mice; eight miRNAs corresponded to target sites in seven genes identified as being associated with heat tolerance pathways (Hspa1a, Dnajb1, Dnajb4, Dnajb6, Hspa2, Hspb3 and Hspb7). Conclusions The combination of mRNA and miRNA data from the skeletal muscle of adult mice following heat stress provides new insights into the pathophysiology of thermoregulatory disturbances of heat intolerance

Individual differences in emotion-cognition interactions: Emotional valence interacts with serotonin transporter genotype to influence brain systems involved in emotional reactivity and cognitive control

The serotonin transporter gene (5-HTTLPR) influences emotional reactivity and attentional bias toward or away from emotional stimuli, and has been implicated in psychopathological states, such as depression and anxiety disorder. The short allele is associated with increased reactivity and attention toward negatively-valenced emotional information, whereas the long allele is associated with increased reactivity and attention towardpositively-valenced emotional information. The neural basis for individual differences in the ability to exert cognitive control over these bottom-up biases in emotional reactivity and attention is unknown, an issue investigated in the present study. Healthy adult participants were divided into two groups, either homozygous carriers of the 5-HTTLPR long allele or homozygous carriers of the short allele, and underwent functional magnetic resonance imaging (fMRI) while completing an Emotional Stroop-like task that varied in the congruency of task-relevant and task-irrelevant information and the emotional valence of the task-irrelevant information. Behaviorally, participants demonstrated the classic “Stroop effect” (responses were slower for incongruent than congruent trials), which did not differ by 5-HTTLPR genotype. However, fMRI results revealed that genotype influenced the degree to which neural systems were engaged depending on the valence of the conflicting task-irrelevant information. While the “Long” group recruited prefrontal control regions and superior temporal sulcus during conflict when the task-irrelevant information was positively-valenced, the “Short” group recruited these regions during conflict when the task-irrelevant information was negatively-valenced. Thus, participants successfully engaged cognitive control to overcome conflict in an emotional context using similar neural circuitry, but the engagement of this circuitry depended on emotional valence and 5-HTTLPR status. These results suggest that the interplay between emotion and cognition is modulated, in part, by a genetic polymorphism that influences serotonin neurotransmission