Optimization of Cement Grouts Containing Silica Fume and Viscosity Modifying Admixture

There is an increasing need to identify the effect of mix composition on the rheological properties of cementitious grouts using minislump, Marsh cone, cohesion plate, washout test, and cubes to determine the fluidity, the cohesion, and other mechanical properties of grouting applications. Mixture proportioning involves the tailoring of several parameters to achieve adequate fluidity, cohesion, washout resistance and compressive strength. This paper proposes a statistical design approach using a composite fractional factorial design which was carried out to model the influence of key parameters on the performance of cement grouts. The responses relate to performance included minislump, flow time using Marsh cone, cohesion measured by Lombardi plate meter, washout mass loss and compressive strength at 3, 7, and 28 days. The statistical models are valid for mixtures with water-to-binder ratio of 0.37–0.53, 0.4–1.8% addition of high-range water reducer (HRWR) by mass of binder, 4–12% additive of silica fume as replacement of cement by mass, and 0.02–0.8% addition of viscosity modifying admixture (VMA) by mass of binder. The models enable the identification of underlying factors and interactions that influence the modeled responses of cement grout. The comparison between the predicted and measured responses indicated good accuracy of the established models to describe the effect of the independent variables on the fluidity, cohesion, washout resistance and the compressive strength. This paper demonstrates the usefulness of the models to better understand trade-offs between parameters. The multiparametric optimization is used to establish isoresponses for a desirability function for cement grout. An increase of HRWR led to an increase of fluidity and washout, a reduction in plate cohesion value, and a reduction in the Marsh cone time. An increase of VMA demonstrated a reduction of fluidity and the washout mass loss, and an increase of Marsh cone time and plate cohesion. Results indicate that the use of silica fume increased the cohesion plate and Marsh cone, and reduced the minislump. Additionally, the silica fume improved the compressive strength and the washout resistance.

Will attracting the creative class boost economic growth in old industrial regions? A case study of Scotland

Attracting in-migration of the creative class has been argued by Florida (2002) to be a route to higher economic growth in the era of the knowledge economy. This paper critically evaluates this proposition in relation to old industrial regions using the example of Scotland. The paper presents an assessment of, in the first instance, to what extent there is a shortage of skilled, talented and entrepreneurial individuals and, in the second instance, whether a talent attraction strategy alone can hope to attract such people to Scotland. It is proposed that for most migrants the availability of appropriate economic opportunities is a prerequisite for mobility. However, despite uncertain evidence that place attractiveness is a catalyst to mobility among the so-called creative class, this is not a reason for dismissing talent attraction programmes. Instead it is argued that talent attraction programmes have the potential to contribute to old industrial economies, but their success will be greatest when talent attraction is carefully targeted and based on economic realities rather than the marketing of ethereal conceptions of place attractiveness.

Analyzing the Influence of Gender Upon High Technology Venturing Within the Context of Business Incubation

We explore the influence of sex role attribution and associated gendered ascriptions upon the entrepreneurial experiences of a female high-technology business owner operating within the context of business incubation. Our literature analysis and empirical evidence suggest that stereotypical gendered expectations surrounding incubated high-technology venturing reproduce masculine norms of entrepreneurial behavior. The adoption of a gendered perspective to explore the experience of business incubation responds to contemporary calls to embed feminist analyses within the entrepreneurial field of enquiry. Furthermore, we draw upon evidence from a detailed case study informed by a life history narrative to explore a female entrepreneur's experience of incubated high-technology entrepreneurship. © 2011 Baylor University.

Sense and sensibility: The role of business incubator client advisors in assisting high-technology entrepreneurs to make sense of investment readiness status

For high-technology entrepreneurs, attaining an appropriate level of investment to support new ventures is challenging as substantial investment is usually required prior to revenue generation. Consequently, entrepreneurs must present their firms as investment ready in the context of an uncertain market response and an absence of any trading history. Gaining tenancy within a business incubator can be advantageous to this process given that placement enhances entrepreneurial contact with potential investors whilst professional client advisors (CAs) use their expertise to assist in the development of a credible business plan. However, for the investment proposal to be successful, it must make sense to fund managers despite their lack of technological expertise and product knowledge. Thus, this article explores how incubator CAs and entrepreneurs act in concert to mould innovative ideas into plausible business plans that make sense to venture fund investors. To illustrate this process, we draw upon empirical evidence which suggests that CAs act as sense makers between venture fund managers (VFMs) and high-technology entrepreneurs, yet their role and influence appears undervalued. These findings have implications for entrepreneurial access to much needed funding and also for the identification of investment opportunities for VFMs. © 2011 Taylor & Francis.

Purchasing power parity versus fixed exchange rate rules: A stability and welfare analysis

This paper evaluates the desirability of PPP rules vis-á-vis fixed exchange rates both in terms of welfare and stability properties. The analysis is conducted within a small open-economy New Keynesian framework extended to include a cost channel. In terms of stability, we find that while the equilibrium is always unique under fixed exchange rates its uniqueness critically depends upon the presence/absence of the cost channel under a PPP rule. Overall, then, in terms of welfare a fixed exchange rate always outperforms a PPP rule.

The early-stage risk capital market in Scotland since 2000: issues of scale, characteristics and market efficiency

In this paper we provide a detailed profile and analysis of the regional risk capital market in Scotland, using an innovative methodology and specially developed databases which cover risk capital investment in young companies in the periods 2000–04 and 2005–07. This identifies the investment activity of all actors in the market and provides estimates of the total flow of risk capital investment into early-stage Scottish companies over the period. The paper concludes by drawing out the implications for policy makers (providing a more robust evidence base for the development, implementation and monitoring of policy) and for academic researchers (on the methodologies for estimating market scale and efficiency).

Ownership structure, organisational flexibility and store performance in retail chains.

Drawing on agency and flexible capability perspectives, the authors develop a theoretical framework explaining the impact of ownership structure on organisational flexibility and store performance in retail chains. The researchers argue that franchised stores attract more entrepreneurial managers with more flexible capabilities and they have a stronger incentive to align their flexible capabilities with the demands of the business environment. A sample of 105 franchised and company-owned stores of an optical retail chain is used to test the hypotheses. Furthermore, the study found strong support for the hypotheses that 'Franchised stores have a higher structural flexibility than company-owned stores', but only weak support for operational and strategic flexible capabilities. Furthermore, in line with the study's theoretical framework, it has been found that in a highly turbulent business environment, franchised stores perform better than company-owned stores. The paper concludes with a discussion of the implications for theory development and management of ownership structures in retail chains.

Ascending Out of Poverty: An analysis of family histories in Kenya

This paper looks at inheritance through minimally-structured interviews with several generations of Kenyan families, seeking to explain that the how and why of poverty can be understood in the wider family context. Five main routes for ascending out of poverty were identified: (1) the gradual accumulation of resources due to income deriving from cash crops; (2) the gradual accumulation of resources due to income from non-farm work, including remittances from family member who have moved away for work; (3) the role of education, particularly skills training opposed to academic qualification, in helping provide employment; (4) accessing financial assets through support both from extended family members and from informal support mechanisms; (5) stability and benefits accruing from long-term strategic planning, including entrepreneurial activity. Both the ascent out of and the descent into poverty can be better conceived as processes, rather than due to chains of discrete events or specific ‘shocks’.

Anger, aggression, and self-harm in PTSD and complex PTSD

This study examined the contribution of complex posttraumatic stress disorder (PTSD) diagnosis and symptomatology to the difficulties of anger, aggression, and self-harm in a Northern Ireland clinical community sample. A "current complex PTSD" (CCPTSD) group (n = 11) was compared with a "current PTSD" group (n = 31) on self-report measures of these variables. The CCPTSD group demonstrated significantly higher levels of physical aggression and selfharm than the PTSD group. The complex PTSD symptom of 'alterations in self-perception' was a significant predictor of aggression and history of self-harm, suggesting the potential role of posttraumatic shame and self-loathing in PTSD theoretical models of these destructive behaviors. Social desirability was a notable confounding influence in the assessment of anger, aggression, and self-harm in traumatised individuals.

Trauma typology as a risk factor for aggression and self-harm in a complex PTSD population: The mediating role of alterations in self-perception

This study examined the role of prolonged, repeated traumatic experiences such as childhood and sectarian trauma in the development of posttraumatic aggression and self-harm. Forty-four adult participants attending therapy for complex trauma in Northern Ireland were obtained via convenience sampling. When social desirability was controlled, childhood emotional and physical neglect were significant correlates of posttraumatic hostility and history of self-harm. These relationships were mediated by alterations in self-perception (e.g., shame, guilt). Severity of sectarian-related experiences was not related to self-destructive behaviors. Moreover, none of the trauma factors were related to overt aggressive behavior. The findings have implications for understanding risk factors for posttraumatic aggression and self-harm, as well as their treatment. © 2013 Copyright Taylor & Francis Group, LLC.

Incubation or Induction? Gendered Identity Work in the Context of Technology Business Incubation

While there is a substantial body of literature exploring the influence of business incubation upon early stage firms, this debate remains almost entirely gender blind. This article challenges this assumption by adopting a feminist perspective to reveal business incubation as a gendered process shaping the identity work undertaken by women seeking legitimacy as technology venturers. In so doing, we critically evaluate prevailing normative analyses of the business incubation process and entrepreneurial legitimation. To illustrate this argument, we draw upon empirical evidence which reveals technology incubation as a legitimating induction process encouraging women to reproduce masculinized representations of the normative technology entrepreneur.