Contradictions in social enterprise: do they draw in straight lines or circles?

This paper provides a critical perspective on the discourse surrounding the concept of social enterprise. The paper shifts the lens away from numbers to consider how actors see themselves as social enterprises. The authors make sense of the foundations upon which the concept of social enterprise and entrepreneurship is ‘drawn’ – quite literally – by considering linear models and diagrams that analyse social enterprise on a continuum between non-profit (mission) and profit (market) orientation. A great deal has been made of the success and growth of social enterprise. The imagery in the literature reflects an emphasis on growth resulting from ‘the rising tide of commercialisation of non-profit organisations’ (Dees, 1998) with the result that the CBI now includes over 50,000 organisations in a social enterprise sector (SBS, 2005). Despite reports of rapid growth, there is awareness that ‘take-up of social enterprise model … is patchy and fails to reflect the enthusiasm with which it is discussed’ (Stevenson in Westall &amp; Chalkley 2007). We ask why? A methodological approach involving visual drawings by actors reveals stories and sensemaking experiences of social enterprises. Open conversations enabled the researchers to gain deep insights that would not have been as insightful through a quantitative approach. The key findings suggest: Firstly, participants report tensions when pursuing social and economic goals simultaneously. Secondly, whilst some welcome opportunities that are emerging, others perceive substantive threats to the third sector. Thirdly, Social enterprise emerges as a diverse and heterogeneous movement located at the boundaries of public, private and voluntary sectors. At each boundary, different constitutional forms and practices are seen. In conclusion, it is argued that the linear perspective itself gives the impression that there is a ‘patchy’ take up of social enterprise. A heterogeneous perspective reveals that theory and policy development is patchy, rather than social enterprise practices. The unique contribution this research paper offers is within the depth of enquiry and insight into the actual practices provided from those within the field. The critical perspective is taken from the literature and discussed in the settings of the actors in the field which provides practitioners, business support agencies and academics with a different level of empirical investigation that captures an originality and narrative that has barely been explored before.</p

Seeing social enterprise through the theoretical conceptualisation of ethical capital

Objectives: Current conceptualisations of social enterprise fail to fully satisfy an understanding of the movement. A focus on the economic implies a business model where deep tensions lie. A focus on social capital offers a different frame of reference, yet both these conceptualisations fail to fully identify the phenomena that is social enterprise. The objective of this paper seeks to fill that gap. Ethical capital is offered here as the missing conceptualisation in the field of social enterprise. Prior work: Pearce (2003) describes social enterprises as part of the third system, closer to the first system (private business), than the second system (public provision), yet primarily social and secondly a business. Social Enterprises are described as trading organisations in a market (Pearce 2003). A focus and operationalisation for social enterprises to be ‘business-like’ and ‘entrepreneurial’ is well documented (Leadbeater 1997; Dees 1998; Nicholls 2006b). Approach: Yet, if as part of the third sector, social enterprises are as Dart (2004) suggests; ‘blurring the boundaries between non-profit and profit’, but what blurs? What is compromised? What exactly is lost (or gained)? What challenges are there for social enterprises? And is a managerialist ideology taking precedence over the social? This paper provides a conceptual paper that seeks to outline the arguments on the table and develop an ethical capital conceptualisation of social enterprise. Results: This paper very much aims at starting the process of intellectual debate about the notion of ethical capital in social enterprises. The conclusions of this paper outline further research questions that need to be addressed in order to fully develop this concept. Implications: The current ideology of the neo-classical economic paradigm it is argued in the paper pursues interests towards the self and towards the erosion of the moral basis of association. The outcome leaves society with a problem of low ethical virtue - the implications of this paper are that social enterprises maximise ethical virtue beyond any other form of organisation and as such hold great value beyond their missions and values. Value: This paper offers great value in the understanding of social enterprise through fresh insight into the conceptualisation. A critical perspective to the current literature is taken and discussed but though the introduction of ethical capital this paper takes our understanding of the value of the sector into another light, providing practitioners, business support agencies and academics alike with a different level of conceptualisation that has not been explored before.</p

Population inversion in optically pumped asymmetric quantum well terahertz lasers

Intersubband carrier lifetimes and population ratios are calculated for three- and four-level optically pumped terahertz laser structures. Laser operation is based on intersubband transitions between the conduction band states of asymmetric GaAs-Ga(1 – x)Al(x)As quantum wells. It is shown that the carrier lifetimes in three-level systems fulfill the necessary conditions for stimulated emission only at temperatures below 200 K. The addition of a fourth level, however, enables fast depopulation of the lower laser level by resonant longitudinal optical phonon emission and thus offers potential for room temperature laser operation. © 1997 American Institute of Physics

Time-dependent Landauer-Büttiker approach to charge pumping in ac-driven graphene nanoribbons

We apply the recently developed partition-free time-dependent Landauer-Büttiker (TD-LB) formalism to the study of periodically driven transport in graphene nanoribbons (GNRs). When an ac driving is applied, this formalism can be used to prove generic conditions for the existence of a nonzero dc component of the net current (pump current) through the molecular device. Time-reversal symmetry breaking in the driving field is investigated and found to be insufficient for a nonzero pump current. We then derive explicit formulas for the current response to a particular biharmonic bias. We calculate the pump current through different GNR configurations and find that the sign and existence of a nonzero pump current can be tuned by simple alterations to the static parameters of the TD bias. Furthermore, we investigate transient currents in different GNR configurations. We find a selection rule of even and odd harmonic response signals depending on a broken dynamical inversion symmetry in the bias

Electron Traversal Times in Disordered Graphene Nanoribbons

Using the partition-free time-dependent Landauer–Büttiker formalism for transient current correlations, we study the traversal times taken for electrons to cross graphene nanoribbon (GNR) molecular junctions. We demonstrate electron traversal signatures that vary with disorder and orientation of the GNR. These findings can be related to operational frequencies of GNR-based devices and their consequent rational design

Variation of Thermochromic Glazing Systems Transition Temperature, Hysteresis Gradient and Width Effect on Energy Efficiency

Due to increasing pressure to reduce the energy demand in buildings, thermochromic thin film based glazing has become a recognized potential solution due to the intrinsic ability to modulate the solar heat gain of a window as a function of the materials temperature. These “intelligent” glazings have been investigated for several years, and it has been found that, through variation of synthetic route, the thermochromic properties (transition temperature, hysteresis gradient and width) can be altered; however, less attention has been applied to how such alterations affect the overall energy savings attributed to the materials. In this study the building simulation software EnergyPlus TM has been used to model a series of idealized thermochromic spectra in a series of different environments to evaluate their energy saving potential against both clear glass systems and industry standards. The idealized spectra are used to see what effect each of the materials thermochromic properties and therefore elucidate which are the most important with respect to the energy saving properties. It was found that the best thermochromic materials were those with a narrow sharp hysteresis and a low transition temperature and result in an increase in energy saving between 30%–45% across the different environments compared to clear glass systems

The effect of transition hysteresis width in thermochromic glazing systems

Thermochromic glazing theoretically has the potential to lead to a large reduction in energy demand in modern buildings by allowing the transmission of visible light for day lighting whilst reducing unwanted solar gain during the cooling season, but allowing useful solar gain in the heating season. In this study building simulation is used to examine the effect of the thermochromic transition hysteresis width on the energy demand characteristics of a model system in a variety of climates. The results are also compared against current industry standard glazing products. The results suggest that in a warm climate with a low transition temperature and hysteresis width energy demand can be reduced by up to 54% compared to standard double glazing

Sub-linear radiation power dependence of photo-excited resistance oscillations in two-dimensional electron systems

We find that the amplitude of the $R_{xx}$ radiation-induced magnetoresistance oscillations in GaAs/AlGaAs system grows nonlinearly as $A \propto P^{\alpha}$ where $A$ is the amplitude and the exponent $\alpha < 1$. %, with $\alpha \rightarrow 1/2$ in %the low temperature limit. This striking result can be explained with the radiation-driven electron orbits model, which suggests that the amplitude of resistance oscillations depends linearly on the radiation electric field, and therefore on the square root of the power, $P$. We also study how this sub-linear power law varies with lattice temperature and radiation frequency.Comment: 5 pages, 3 figure

Theory of phonon-drag thermopower of extrinsic semiconducting single-wall carbon nanotubes and comparison with previous experimental data

A theoretical model for the calculation of the phonon-drag thermopower, $S^{g}$, in degenerately doped semiconducting single-wall carbon nanotubes (SWCNTs) is proposed. Detailed calculations of $S^{g}$ are performed as a function of temperature, tube radius and position of the Fermi level. We derive a simple analytical expression for $S^{g}$ that can be utilized to determine the free carrier density in doped nanotubes. At low temperatures $S^{g}$ shows an activated behavior characteristic of the one-dimensional (1D) character of carriers. Screening effects are taken into account and it is found that they dramatically reduce the magnitude of $S^{g}$. Our results are compared with previous published experimental data in bulk p-doped SWCNT materials. Excellent agreement is obtained in the temperature range 10-200 K for a consistent set of parameters. This is a striking result in view of the complexity of these systems.Comment: 21 pages, 6 figures. This version has been accepted for publication in Phys. Rev.