There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

Attachment--and loss.

/pdf/the-theory-of-industrial-organization-19bejph0ej.pdf

The Theory of Industrial Organization

An introduction to heat transfer

Social scientists often estimate models from correlational data, where the independent variable has not been exogenously manipulated; they also make implicit or explicit causal claims based on these models. When can these claims be made? We answer this question by first discussing design and estimation conditions under which model estimates can be interpreted, using the randomized experiment as the gold standard. We show how endogeneity – which includes omitted variables, omitted selection, simultaneity, common-method variance, and measurement error – renders estimates causally uninterpretable. Second, we present methods that allow researchers to test causal claims in situations where randomization is not possible or when causal interpretation could be confounded; these methods include fixed-effects panel, sample selection, instrumental variable, regression discontinuity, and difference-in-differences models. Third, we take stock of the methodological rigor with which causal claims are being made in a social sciences discipline by reviewing a representative sample of 110 articles on leadership published in the previous 10 years in top-tier journals. Our key finding is that researchers fail to address at least 66% and up to 90% of design and estimation conditions that make causal claims invalid. We conclude by offering 10 suggestions on how to improve non-experimental research.

On making causal claims : A review and recommendations

With the concept of circular economy gaining increasing momentum, its connection to consumer behavior, particularly focusing on fair trade, has been relatively unexplored. Building on cognitive-affective personality system theory, we examine the role of consumer personality traits as drivers of fair trade engagement and its subsequent impact on ethically-minded behavior concerning circular economy issues. Adopting a mixed-method approach, comprising a quantitative survey among 323 consumers in the UK and India and a qualitative study among 18 British consumers, we found that extraversion, agreeableness, and conscientiousness positively affect consumer fair trade engagement, whereas neuroticism has a negative effect, and openness has no significant impact. Consumer fair trade engagement was subsequently revealed to positively influence ethically-minded behavior related to circular economy. The association between consumer fair trade engagement and ethically-minded behavior was stronger in older, more educated, and high-income consumers, whereas gender had no moderating role. 

Integrating fair trade with circular economy: Personality traits, consumer engagement, and ethically-minded behavior

Ground heat exchangers in conjunction with shallow geothermal energy system applications have received significant attention in the case of renewable energy. Soil thermal properties such as thermal conductivity and specific or volumetric heat capacity are important aspects for the design of such systems, affecting the performance. They can be obtained with the use of empirical prediction models, laboratory tests and/or in situ tests. Laboratory tests can be performed either under steady-state or under transient conditions and have the advantage of requiring small volumes of soil and producing fast results. There are many types of heat probes commercially available, with limited—though—comparative assessment available in the literature. The current paper deals with the assessment of ground characteristics of seven samples of soil and rock collected from a certain area in the Mediterranean island of Cyprus. Such properties are the thermal conductivity, the thermal diffusivity, the volumetric heat capacity, but there are some other physical properties also. The laboratory testing was done under transient conditions and included measurements taken by two needle probes and one surface probe from two different commercial apparatuses. Comparison of the obtained results for the thermal properties of the samples was made and was also supported by numerical simulations using the COMSOL Multiphysics software through a finite element analysis method on the convection–diffusion equation for heat transfer. Laboratory testing on physical properties of the samples such as moisture content, specific gravity, permeability and particle size distribution was also performed, yielding useful results related to the assessment of the thermal properties.

Thermal and physical characteristics of soils in Cyprus for use in shallow geothermal energy applications

Access to energy and in particular electricity is viewed as a fundamental right of every household. The accessible source of electricity gets distributed to different electrical loads within the household without people being aware of the individual consumption per load, due to the fact that the overall cost is reported as a single number in the electricity bill. In this study we investigated the awareness and knowledge of household consumers with regard to issues associated with electricity consumption and cost. As a first stage, a sample of 300 households all around Cyprus was randomly selected in January 2010. The occupants were asked to provide relevant information about their household as well as answer some survey questions associated with knowledge of electricity consumption. The survey demonstrated clearly that most people are not aware of electricity consumption and cost, indicating a potential for reducing unnecessary consumption. The second stage was the installation of 50 smart monitors, one per household, with a small display indicating the cost of electricity consumed per hour. The monitor enabled the occupants of the household to identify the cost for appliances, lighting and so forth, by observing the change in the displayed cost when the load was switched on. The device became an effective educational tool that motivated the users to be more alert in switching off unnecessary loads. The third stage consists of monitoring the consumption of each of the 50 households over a 2 year period 1 year prior to the use of the monitoring device and 1 after. The results so far demonstrate clearly that the information provided by the device led to changes in the use of electrical loads that resulted in an average of 25% savings ranging from a minimum of 10% to a maximum of just over 40%. The study of the 50 households helped to identify some common areas of savings which were verbally communicated to the remaining 250 households participating in the project but did not have access to a monitoring device. In those cases the average savings were about 10%. The study clearly demonstrates that saving electrical energy has a lot to do with education and awareness regarding costs of different electrical loads. The use of a smart device that allows people to observe cost changes for different loads seems to be much more effective than booklets and verbal suggestions regarding energy savings. In a future study, the analysis of a statistical model on the profile of the average Cypriot household will be attempted. Features like education, financial status, age and other important factors will be tested against different ways of informing and educating people in changing their habits on electricity consumption.

/pdf/domestic-electricity-consumption-and-the-public-awareness-4eluke038q.pdf

Domestic Electricity Consumption and the Public Awareness Factor

At the first World Sloshing Dynamics Symposium that took place during the Nineteenth (2009) International Offshore and Polar Engineering (ISOPE) Conference in Osaka, Japan, it was made clear that simplified academic problems have an important role to play in the understanding of liquid impacts. The problem of the impact of a mass of liquid on a solid structure is considered. First the steady two-dimensional and irrotational flow of an inviscid and incompressible fluid falling from a vertical pipe, hitting a horizontal plate and flowing sideways, is considered. A parametric study shows that the flow can either leave the pipe tangentially or detach from the edge of the pipe. Two dimensionless numbers come into play: the Froude number and the aspect ratio between the falling altitude and the pipe width. When the flow leaves tangentially, it can either be diverted immediately by the plate or experience squeezing before being diverted. The profile of the pressure exerted on the plate is computed and discussed. Then the same problem is revisited with the inclusion of compressibility effects, both for the falling liquid and for the gas surrounding it. An additional dimensionless number comes into play, namely the Mach number. Finally, a discussion on the differences between the incompressible and compressible cases is provided.

/pdf/on-the-effect-of-compressibility-on-the-impact-of-a-falling-4ms6d1953j.pdf

On the Effect of Compressibility On the Impact of a Falling Jet

Soil thermal characterization is an important aspect affecting the performance of Ground Heat Exchangers (GHE) in a Shallow Geothermal Energy (SGE) system application. Thermal conductivity and specific heat capacity are the sole requirements in designing such systems and can be obtained using empirical prediction models, laboratory tests and in situ tests. Laboratory thermal tests can be performed under steady-state or transient conditions. Transient tests have the advantage of being fast and of requiring a small volume of soil. This has led to recent developments and types of heat probes commercially available, but for which there is limited comparative assessment of results. This paper focuses on the evaluation of thermal properties, namely the ground thermal conductivity, specific heat capacity and thermal diffusivity by means of two different probes; a needle probe and a surface probe, and on comparing and testing their accuracy. Comparison of the different samples was also performed using two different transient needle probes, from two commercially available equipment, Isomet-2104 and Hukseflux-TPSY02. The laboratory measurements are supported by numerical modelling using the COMSOL Multiphysics software which applies a finite-element analysis method on the convection-diffusion equation for heat transfer.

Paul Christodoulides

Papers

Integrating fair trade with circular economy: Personality traits, consumer engagement, and ethically-minded behavior

Thermal and physical characteristics of soils in Cyprus for use in shallow geothermal energy applications

Domestic Electricity Consumption and the Public Awareness Factor

On the Effect of Compressibility On the Impact of a Falling Jet

Assessment and Comparison of Soil Thermal Characteristics by Laboratory Measurements