Turbofan noise generation. Volume 1: Analysis

Computer programs were developed which calculate the in-duct acoustic modes excited by a fan/stator stae operating at subsonic tip speed. Three noise source mechanisms are included: (1) sound generated by the rotor blades interacting with turbulence ingested into, or generated within, the inlet duct; (2) sound generated by the stator vanes interacting with the turbulent wakes of the rotors blades; and (3) sound generated by the stator vanes interacting with the mean velocity deficit wakes of the rotor blades. The fan/stator stage is modeled as an ensemble of blades and vanes of zero camber and thickness enclosed within an infinite hard-walled annular duct. Turbulence drawn into or generated within the inlet duct is modeled as nonhomogeneous and anisotropic random fluid motion, superimposed upon a uniform axial mean flow, and convected with that flow. Equations for the duct mode amplitudes, or expected values of the amplitudes, are derived

Turbofan noise generation. Volume 2: Computer programs

The use of a package of computer programs developed to calculate the in duct acoustic mods excited by a fan/stator stage operating at subsonic tip speed is described. The following three noise source mechanisms are included: (1) sound generated by the rotor blades interacting with turbulence ingested into, or generated within, the inlet duct; (2) sound generated by the stator vanes interacting with the turbulent wakes of the rotor blades; and (3) sound generated by the stator vanes interacting with the velocity deficits in the mean wakes of the rotor blades. The computations for three different noise mechanisms are coded as three separate computer program packages. The computer codes are described by means of block diagrams, tables of data and variables, and example program executions; FORTRAN listings are included

Prevalence and awareness of type 2 diabetes mellitus among adult population in Mwanza city, Tanzania

Type 2 diabetes mellitus (T2DM) prevalence is increasing rapidly around the world. This cross-sectional study was conducted to assess the prevalence and awareness of type 2 diabetes mellitus in Mwanza city, Tanzania. A multistage random sampling technique was used to obtain representative subjects. Information about causes and risk factors were collected using structured questionnaire. In addition, community random blood glucose testing was employed to identify those at risk. Subjects with ≥200mg/dl on the following day were subjected to fasting blood glucose testing and they were confirmed to have T2DM if they had blood glucose level of ≥126mg/dl. In each subject, height, weight, waist and hip circumferences and total fat and fat free mass were measured using standard procedures. A total of 640 participants were included in this study, 55% were females and 45% were males. Mean age of the respondent was 43.84 ± 10.80 years. Most (46.4%) respondents were in the age group 30-40 years. Mean age for females was 44.0 ± 10.31 years while for males was 43.6 ± 11.3 years (Table 1). Overall prevalence of T2DM was 11.9%, (n=76). Prevalence was high in females (7.2%; n=46) than in males (4.7%; n=30). The age between 41-50 years had the highest prevalence of T2DM 28.6% followed by 51-60 years age group (17.2%). Significant independent associations were found for age (OR 3.88, 95% CI: 2.16-6.95) positive first degree relative with T2DM (OR 1.34; 95%C: 1.10-1.64) alcohol intake (OR 1.23; 95%CI: 1.02-1.48,) smoking (OR 3.86; 95%CI: 2.57-5.78) and hypertension (OR 0.096; 95%CI: 1.954-18.251). Only 49.2 (n=315) of the respondents knew about the causes and symptoms of T2DM. Public education on T2DM should be emphasized and routine measurement of blood glucose levels is recommended among adults

Pharmacokinetics and dosage adjustment of cefotiam in renal impaired patients

The pharmacokinetics of cefotiam were investigated after intravenous administration of 1 g to 2 healthy volunteers with normal renal function and to 16 patients whose creatinine clearance ranged from 4.7 to 0.11/h (78 to 1.66 ml/min). The elimination half-life varied from 1.1 h in normal subjects to 13 h in patients and the total plasma clearance from 21 to 0.6 1/h (350 to 10 ml/min). The urinary recovery decreased from 62% of the dose in normal subjects to 1.1% in patients, and the renal clearance from 15 to 0.03 l/h (250 to 0.5 ml/min). Plasma and renal clearances of cefotiam correlated well with the creatinine clearance. The dosage schedule for cefotiam in patients with normal renal function can be used in the presence of renal failure when the creatinine clearance is equal to or greater than 1 1/h (16.6 ml/min). For patients whose creatinine clearance is less than 1 1/h, the dose must be decreased to 75% of that for a patient with normal renal function only when it is given every 6 or 8

The first millikelvin cryocooler (mKCC): Design and performance

The design and performance of the first millikelvin cryocooler (mKCC) is presented. The mKCC is based upon a tandem Adiabatic Demagnetisation Refrigerator (ADR) that uses two single ADRs operated out of phase and connected to a common cold stage to provide continuous cooling. Development of this mKCC is part of an on-going research program to ultimately achieve sub-100 mK continuous cooling and builds upon our previous research, with each single ADR in the mKCC being a fast thermal response miniature ADR using a single crystal tungsten magnetoresistive heat switch as detailed in our 2015 publication [1]. With the mKCC operating from a 3.6 K bath temperature, the goal is to achieve continuous cooling at 250 mK (sub-100 mK is not possible without additional pre-cooling). The mKCC has dimensions of 120 × 56 × 228 mm and a mass of 4.67 kg. It can operate on very fast timescales – each superconducting magnet can be ramped to 2 Tesla in 30 s and the Chromium Potassium Alum pills have a measured sub-second thermal response, resulting in each miniature ADR being recycled in minutes. Unconventionally, the mKCC uses single crystal tungsten magnetoresistive heat switches. We present the performance of the first version of the fully automated mKCC (from a 3.6 K bath temperature), which has been determined by undertaking a range of tests analysing the cool down from 3.6 K to the operating temperature, the baseline performance, the thermal stability at the continuous stage, the reliability and repeatability in performance and the cooling power at a range of operating temperatures. The base temperature has been measured to be 750 mK and we have demonstrated that the mKCC can be operated at any temperature between 750 mK and 3 K, with the program-controlled transition between operating temperatures taking approximately 60 s. The cooling power of the mKCC (in addition to parasitic load) has been measured at a range of temperatures between 800 mK and 3 K by applying a heat load to the continuous stage via a heater; the maximum cooling power at 800 mK is 6 µW, increasing to 32 µW at 1 K and 412 µW at 3 K. In addition we conducted a six-week continuous test during which each ADR undertook 5,498 5.5 min cycles with no significant variation in performance detected. To conclude, we compare the measured performance of the mKCC to the expected performance based on mathematical thermal modelling and the performance of the miniature ADR. Whilst the measured performance does not meet the expected performance in terms of base temperature or cooling power, we have identified the limiting factors and discuss them here

Light environment drives evolution of color vision genes in butterflies and moths

Opsins, combined with a chromophore, are the primary light-sensing molecules in animals and are crucial for color vision. Throughout animal evolution, duplications and losses of opsin proteins are common, but it is unclear what is driving these gains and losses. Light availability is implicated, and dim environments are often associated with low opsin diversity and loss. Correlations between high opsin diversity and bright environments, however, are tenuous. To test if increased light availability is associated with opsin diversification, we examined diel niche and identified opsins using transcriptomes and genomes of 175 butterflies and moths (Lepidoptera). We found 14 independent opsin duplications associated with bright environments. Estimating their rates of evolution revealed that opsins from diurnal taxa evolve faster—at least 13 amino acids were identified with higher dN/dS rates, with a subset close enough to the chromophore to tune the opsin. These results demonstrate that high light availability increases opsin diversity and evolution rate in Lepidoptera

Evolving friendships and shifting ethical dilemmas: fieldworkers' experiences in a short term community based study in Kenya

Fieldworkers (FWs) are community members employed by research teams to support access to participants, address language barriers, and advise on culturally appropriate research conduct. The critical role that FWs play in studies, and the range of practical and ethical dilemmas associated with their involvement, is increasingly recognised. In this paper, we draw on qualitative observation and interview data collected alongside a six month basic science study which involved a team of FWs regularly visiting 47 participating households in their homes. The qualitative study documented how relationships between field workers and research participants were initiated, developed and evolved over the course of the study, the shifting dilemmas FWs faced and how they handled them. Even in this one case study, we see how the complex and evolving relationships between fieldworkers and study participants had important implications for consent processes, access to benefits and mutual understanding and trust. While the precise issues that FWs face are likely to depend on the type of research and the context in which that research is being conducted, we argue that appropriate support for field workers is a key requirement to strengthen ethical research practice and for the long term sustainability of research programmes

Photoelectron diffraction study of ultrathin Fe films on Cu{111}

Using photoelectron diffraction in the scanned-energy mode we show that at 300 K iron grows pseudomorphically on Cu{111} up to a thickness of about two equivalent monolayers. The Fe-Cu layer separation is 1.99 Å. Above this thickness the film becomes bcc with {110} orientation and is aligned such that the 〈111〉 rows are parallel to the 〈110〉 rows of the fcc{111} surface (Kurdjumov-Sachs orientation). The Fe-Fe first-layer separation is 1.95 Å

On the segmentation and classification of hand radiographs

This research is part of a wider project to build predictive models of bone age using hand radiograph images. We examine ways of finding the outline of a hand from an X-ray as the first stage in segmenting the image into constituent bones. We assess a variety of algorithms including contouring, which has not previously been used in this context. We introduce a novel ensemble algorithm for combining outlines using two voting schemes, a likelihood ratio test and dynamic time warping (DTW). Our goal is to minimize the human intervention required, hence we investigate alternative ways of training a classifier to determine whether an outline is in fact correct or not. We evaluate outlining and classification on a set of 1370 images. We conclude that ensembling with DTW improves performance of all outlining algorithms, that the contouring algorithm used with the DTW ensemble performs the best of those assessed, and that the most effective classifier of hand outlines assessed is a random forest applied to outlines transformed into principal components