Temperature dependence of the Laminar burning velocity of methanol flames

To better understand and predict the combustion behavior of methanol in engines, sound knowledge of the effect of the pressure, unburned mixture temperature, and composition on the laminar burning velocity is required. Because many of the existing experimental data for this property are compromised by the effects of flame stretch and instabilities, this study was aimed at obtaining new, accurate data for the laminar burning velocity of methanol–air mixtures. Non-stretched flames were stabilized on a perforated plate burner at 1 atm. The heat flux method was used to determine burning velocities under conditions when the net heat loss from the flame to the burner is zero. Equivalence ratios and initial temperatures of the unburned mixture ranged from 0.7 to 1.5 and from 298 to 358 K, respectively. Uncertainties of the measurements were analyzed and assessed experimentally. The overall accuracy of the burning velocities was estimated to be better than ±1 cm/s. In lean conditions, the correspondence with recent literature data was very good, whereas for rich mixtures, the deviation was larger. The present study supports the higher burning velocities at rich conditions, as predicted by several chemical kinetic mechanisms. The effects of the unburned mixture temperature on the laminar burning velocity of methanol were analyzed using the correlation uL = uL0(Tu/Tu0)α. Several published expressions for the variation of the power exponent α with the equivalence ratio were compared against the present experimental results and calculations using a detailed oxidation kinetic model. Whereas most existing expressions assume a linear decrease of α with an increasing equivalence ratio, the modeling results produce a minimum in α for slightly rich mixtures. Experimental determination of α was only possible for lean to stoichiometric mixtures and a single data point at equivalence ratio= 1.5. For these conditions, the measurement data agree with the modeling results

Time does tell : an analysis of observable audience responses from the 2016 American presidential campaigns

In this study a microanalysis of OAR (Observable Audience Responses) in the 2016 U.S. Presidential Election was conducted. OAR were coded into dimensions including response rate (frequency per minute), response type, and categorised as either a unitary (a single response), composite (two or more simultaneous response types) or sequential (a unitary or composite response that is followed by a different response type) response form. It was found that U.S. audiences made use of all three response forms (unitary, composite, and sequential) and that certain response forms had been under-represented when contrasted with findings from previous research. This study was also the first to measure the duration of OAR in the context of an election, and it was observed that response form significantly affected the duration of response. It was inferred from this that the audiences might select different responses as a means to control the force of reply. This study failed to replicate previous research that had found a correlation between response rate (affiliative OAR per minute) and voter share on polling day, but instead found a stronger, significant correlation between the duration of OAR and voter share. It was interpreted that duration of OAR may be a superior indicator of wider voter enthusiasm as it captures the length of response as well as the incidence

Chemotherapy prior to autologous bone marrow transplantation impairs long-term engraftment in mice

Objective. Autologous bone marrow transplantation in cancer patients is often preceded by multiple cycles of chemotherapy. In this study, we assessed in a mouse model whether stem cells were affected by prior chemotherapy. Methods. Donor mice were treated with three consecutive injections of 150 mg/kg 5-fluorouracil (5-FU). Peripheral blood counts were allowed to recover before the subsequent dose of 5-FU was given. Mice recovered from three doses of 5-FU and showed normal steady-state hematopoiesis. Bone marrow cells from these mice were mixed with congenic competitor cells and transplanted into lethally irradiated recipients. Results. Although in vivo homing of cells from these mice was not impaired, donor leukocyte contribution steadily decreased posttransplantation. In contrast to in vivo homing, both in vitro migration toward stromal-derived factor (SDF)-1 and the average CXC chemokine receptor-4 (CXCR4) expression were lower in 5-FU-treated cells. Moderate reductions in L-selectin and CD11a expression were observed on stem cells of 5-FU-treated mice. CD43, CD44, CD49d, and CD49e were normally expressed and could thus not explain the reduced engraftment of these cells. Conclusion. We therefore conclude that 5-FU either directly damages stem cells or that the replicative stress induced by 5-FU causes a decline in stem cell reconstitution potential resulting in lower chimerism levels posttransplantation, that declines in time. (C) 2003 International Society for Experimental Hematology. Published by Elsevier Inc

Achieving temperature-size changes in a unicellular organism.

The temperature-size rule (TSR) is an intraspecific phenomenon describing the phenotypic plastic response of an organism size to the temperature: individuals reared at cooler temperatures mature to be larger adults than those reared at warmer temperatures. The TSR is ubiquitous, affecting >80% species including uni- and multicellular groups. How the TSR is established has received attention in multicellular organisms, but not in unicells. Further, conceptual models suggest the mechanism of size change to be different in these two groups. Here, we test these theories using the protist Cyclidium glaucoma. We measure cell sizes, along with population growth during temperature acclimation, to determine how and when the temperature-size changes are achieved. We show that mother and daughter sizes become temporarily decoupled from the ratio 2:1 during acclimation, but these return to their coupled state (where daughter cells are half the size of the mother cell) once acclimated. Thermal acclimation is rapid, being completed within approximately a single generation. Further, we examine the impact of increased temperatures on carrying capacity and total biomass, to investigate potential adaptive strategies of size change. We demonstrate no temperature effect on carrying capacity, but maximum supported biomass to decrease with increasing temperature

Are Reports of Psychological Stress Higher in Occupational Studies? A Systematic Review across Occupational and Population Based Studies

This study was funded by the UK Ministry of Defence (MoD)

Effects of perceptions of information overload, noise and environmental demands on wellbeing and academic attainment.

The present research considers components of information overload, which may have a negative impact on wellbeing and academic attainment. 179 university students completed a survey consisting of an information overload scale (IOS) and the wellbeing process questionnaire. Their academic attainment scores were also added to the database. The IOS scale also included questions relating to noise exposure. Both the noise scores and non-noise IOS scores were associated with greater negative wellbeing and lower positive wellbeing. There were no significant effects of noise or IOS scores on academic attainment. Wellbeing is predicted by a number of factors such as exposure to stressors, negative coping, social support and psychological capital. When these established factors were included in the analyses, the effects of noise and other aspects of IOS could be accounted for by exposure to other stressors and were no longer significant predictors of negative or positive wellbeing

Overgrowth of the limbs: A prospective study of 21 Ghanaian patients

Introduction: Overgrowth or gigantism is a congenital enlargement of the soft tissue parts of a limb often with associated enlargement of the skeleton, due to overgrowth of one or more cell types. It may be associated with lipofibromatosis, neurofibromatosis, hyperostosis, or hemihypertrophy. Extent of the burden is unknown locally hence this study.Patients and Methods: A prospective study from January 2005 to December 2009 was undertaken at Komfo Anokye Teaching hospital in Kumasi to document the prevalence and management of patients presenting with congenital enlargement of a limb or digit. The patients were examined clinically and the site of enlargement was recorded. X-rays, pre- and post-operative photographs were taken.Results: Twenty one patients presented with overgrowth of the limbs during the study period, comprising nine males and 12 females. Age range was from 0.3 to 15 years and mean (S.D.) was 7.6 (4.9) years. Twenty eight sites were affected: 16 involving the upper limb; 12, the lower limb, 16 limbs on the right and 12 on the left. The hand was the most affected site (28.7%); followed by the foot (14.3%). The big toe was the most affected digit (10.7%). Debulking was the commonest procedure (71.4%), followed by ray reduction (17.1%) and ray amputation (11.4%).Conclusion: Whereas early surgical intervention is recommended, most of the patients presented late and were treated by extensive debulking, ray reduction and ray amputation. Keywords: gigantism, lipofibromatosis, neurofibromatosis, debulkin