Validation of vapour / water production in a thermoelectric distillation system

In this study, mathematical calculations developed through water-vapour phase-change theory is used to interpret the processes involved in the fresh water production of a thermoelectric distillation system. The rate of water production depends on various parameters of vaporization phenomena such as water and vapour temperatures, pressure, specific volume, heat capacity and water-vapour surface area. The water-vapour surface area is constant 10 x 10 cm2, the initial depth of the sample water is 3 cm and the air occupies the 500 cm3 volume inside the chamber. The volume and the mass of vapour and water at water-vapour interface are calculated through one hour of the system operation. The temperatures of the system components, humidity and water production of the thermoelectric distillation system are measured. As a result, an increase in the temperature of water and hot side of the thermoelectric module leads to an increase in the water production by increasing the vapour formation at atmospheric pressure. After one hour of system operation, the water production reaches 34.5 mL and the humidity inside the chamber increases from 51 % to 74 %. The results also show the distillation ratio is 11.5%. The mathematical calculations validate the experimental data with reasonable agreement

The design and scale-up of spray dried particle delivery systems

INTRODUCTION: The rising demand for pharmaceutical particles with tailored physicochemical properties has opened new markets for spray drying especially for solubility enhancement, improving inhalation medicines and stabilization of biopharmaceuticals. Despite this, the spray drying literature is scattered and often does not address the principles underpinning robust development of pharmaceuticals. It is therefore necessary to present clearer picture of the field and highlight the factors influencing particle design and scale-up. Areas covered: The review presents a systematic analysis of the trends in development of particle delivery systems using spray drying. This is followed by exploring the mechanisms governing particle formation in the process stages. Particle design factors including those of equipment configurations and feed/process attributes were highlighted. Finally, the review summarises the current industrial approaches for upscaling pharmaceutical spray drying. Expert opinion: Spray drying provides the ability to design particles of the desired functionality. This greatly benefits the pharmaceutical sector especially as product specifications are becoming more encompassing and exacting. One of the biggest barriers to product translation remains one of scale-up/scale-down. A shift from trial and error approaches to model-based particle design helps to enhance control over product properties. To this end, process innovations and advanced manufacturing technologies are particularly welcomed

Tacit rejection of policy and teacher ambivalence – insights into English language teaching in Bahrain through actors’ perceptions

This article develops Phillips and Ochs's (2003) framework for policy borrowing, particularly their theorisations about indigenisation of international programmes. It uses the example of communicative language teaching (CLT) in Bahrain, exploring teacher perspectives regarding the effects of CLT on the preexisting arrangements in the national education system and the impact of contextual factors on the potential for CLT implementation. The author conducted qualitative focus groups with English language teachers in 10 schools. The analysis elucidates how teachers were tailoring their own ways through the new reforms to strike a satisfactory balance between the government's aims and the attitudes of the public. It answers the question, "What happens to English language teaching policy when it is transplanted to a different culture?" and concludes that it becomes actively rejected. The conclusion offers a conceptual development of Phillips and Ochs's framework, adding the option of rejection to the indigenisation stage. The article ends with some practical implications

Mathematical model for the irradiance probability density function of a laser beam propagating through turbulent media

We develop a model for the probability density function (pdf) of the irradiance fluctuations of an optical wave propagating through a turbulent medium. The model is a two-parameter distribution that is based on a doubly stochastic theory of scintillation that assumes that small-scale irradiance fluctuations are modulated by large-scale irradiance fluctuations of the propagating wave, both governed by independent gamma distributions. The resulting irradiance pdf takes the form of a generalized K distribution that we term the gamma-gamma distribution. The two parameters of the gamma-gamma pdf are determined using a recently published theory of scintillation, using only values of the refractive-index structure parameter C-n(2) (or Rytov variance) and inner scale l(0) provided with the simulation data. This enables us to directly calculate various log-irradiance moments that are necessary in the scaled plots. We make a number of comparisons with published plane wave and spherical wave simulation data over a wide range of turbulence conditions (weak to strong) that includes inner scale effects. The gamma-gamma pdf is found to generally provide a good fit to the simulation data in nearly all cases tested

Signalling the Dotcom bubble: a multiple changes in persistence approach

This study investigates multiple changes in persistence in the dividend-price and price-earnings ratio of the NASDAQ composite index. Recent time series methods that are capable of signalling and dating asset price bubbles are employed, in particular the method developed by Leybourne et al. (2007). The method allows for breaks between periods in which the data are integrated of order zero I(0) and integrated of order one I(1). The results confirm the existence of the so-called Dotcom bubble with its start and end dates. Furthermore, an unexpected negative bubble was also identified, extending from the beginning of the 1970s to the beginning of the 1990s, suggesting that the NASDAQ stock prices were below their fundamental values as indicated by their dividend yields, finding not previously reported in the literature. As the tools used by regulators take considerable time to take effect, methods capable of picking up warnings signals of the start of a bubble could be very useful. We conjecture that the methodology can also be applied to study recent phenomena in real estate, commodity and foreign exchange markets

Dexamethasone treatment of pregnant F0 mice leads to parent of origin-specific changes in placental function of the F2 generation.

Dexamethasone treatment of F0 pregnant rodents alters F1 placental function and adult cardiometabolic phenotype. The adult phenotype is transmitted to the F2 generation without further intervention, but whether F2 placental function is altered by F0 dexamethasone treatment remains unknown. In the present study, F0 mice were untreated or received dexamethasone (0.2µgg(-1)day(-1), s.c.) over Days 11-15 or 14-18 of pregnancy (term Day 21). Depending on the period of F0 dexamethasone treatment, F1 offspring were lighter at birth or grew more slowly until weaning (P<0.05). Glucose tolerance (1gkg(-1), i.p.) of adult F1 males was abnormal. Mating F1 males exposed prenatally to dexamethasone with untreated females had no effect on F2 placental function on Day 19 of pregnancy. In contrast, when F1 females were mated with untreated males, F2 placental clearance of the amino acid analogue (14)C-methylaminoisobutyric acid was increased by 75% on Day 19 specifically in dams prenatally exposed to dexamethasone on Days 14-18 (P<0.05). Maternal plasma corticosterone was also increased, but F2 placental Slc38a4 expression was decreased in these dams (P<0.05). F0 dexamethasone treatment had no effect on F2 fetal or placental weights, regardless of lineage. Therefore, the effects of F0 dexamethasone exposure are transmitted intergenerationally to the F2 placenta via the maternal, but not paternal, line.This is the accepted manuscript. The final version is available at http://dx.doi.org/10.1071/RD14285