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Better membrane oxygenators need to be developed to enable efficient gas exchange between venous blood and air.

Optimal design and analysis of such devices are achieved through mathematical modeling tools such as computational fluid dynamics (CFD). In this study, a control volume-based one-dimensional (1D) sub-channel analysis code is developed to analyze the gas exchange between the hollow fiber bundle and the venous blood. DIANA computer code, which is popular with the thermal hydraulic analysis of sub-channels in nuclear reactors, was suitably modified to solve the conservation equations for the blood oxygenators. The gas exchange between the tube-side fluid and the shell-side venous blood is modeled by solving mass, momentum and species conservation equations.

Simulations using sub-channel analysis are performed for the first time. As the DIANA-based approach is well known in rod bundle heat transfer, it is applied to membrane oxygenators. After detailed validations, the artificial membrane oxygenator is analyzed for different bundle sizes (L/W) and bundle porosity (epsilon) values, and oxygen saturation levels are predicted along the bundle. The present sub-channel analysis is found to be reasonably accurate and computationally efficient when compared to conventional CFD calculations.

This approach is promising and has far-reaching ramifications to connect and extend a well-known rod bundle heat transfer algorithm to a membrane oxygenator community. As a variety of devices need to be analyzed, simplified approaches will be attractive. Although the 1D nature of the simulations facilitates handling complexity, it cannot easily compete with expensive and detailed CFD calculations.

This work has high practical value and impacts the design community directly. Detailed numerical simulations can be validated and benchmarked for future membrane oxygenator designs.

Future membrane oxygenators can be designed and analyzed easily and efficiently.

The DIANA algorithm is popularly used in sub-channel analysis codes in rod bundle heat transfer. This efficient approach is being implemented into membrane oxygenator community for the first time.

This paper aims to investigate numerically the free convective heat transfer efficiency inside a rectotrapezoidal enclosure filled with Al₂O₃–Cu/water hybrid fluid. The bottom wall of the cavity is uniformly heated, the upper horizontal wall is insulated, and the remaining walls are considered cold. A new thermophysical relation determining the thermal conductivity of the hybrid nanofluid has been established, which produced results those match with experimental ones.

The governing partial differential equations are solved using the finite element method of Galerkin type. The simulated results in terms of streamlines, heat lines and isotherms are displayed for various values of the model parameters, which govern the flow.

The Nusselt number, friction factor and the thermal efficiency index are also determined for the pertinent parameters varying different ratios of the hybrid nanoparticles. The simulated results showed that thermal buoyancy significantly controls the heat transfer, friction factor and thermal efficiency index. The highest thermal efficiency is obtained for the lowest Rayleigh number.

This theoretical study is significantly relevant to the applications of the hybrid nanofluids electronic devices cooled by fans, manufacturing process, renewable energies, nuclear reactors, electronic cooling, lubrication, refrigeration, combustion, medicine, thermal storage, etc.

The results showed that nanoparticle loading intensified the rate of heat transfer and thermal efficiency index at the expense of the higher friction factor or higher pumping power. The results further show that the heat transmission in Al₂O₃–Cu/water hybrid nanofluid at a fixed value of intensified $\phi_{hnf}$ compared to the Al₂O₃/water nanofluid when an amount of higher conductivity nanoparticles (Cu) added to it. Besides, the rate of heat transfer in Cu/water nanofluid declines when the lower thermal conductivity Al₂O₃ nanoparticles are added to the mixture.

Supreme audit institutions (SAIs) examine and supervise the activity of public institutions. The study aims at contributing to the existing literature on public sector audit by providing a classification of 29 European SAIs – 28 national SAIs and the European Court of Auditors (ECA) – based on a broad range of attributes varying from the SAIs' environment to its structure, activity, resources or transparency.

The authors apply quantitative methodology for clustering by means of multidimensional scaling and regressive ordinary least square (OLS) and logistic models.

The authors' results show that SAIs from veteran EU member states (MSs) are more similar amongst them and the same applies to SAIs from Nordic countries, Baltic countries, Western Mediterranean countries and Eastern countries. The authors also perform additional analysis focussing on currently relevant issues such as gender equality, age, environment or the sustainable development goals (SDGs), concluding that the younger the institutions' staff, the more transparent the institutions are. The authors also find that more transparent SAIs report on environmental audits, more prone to cover the SDGs in their audits.

The research is limited in purpose and scope because data cover only Europe. Given the limited number of observations (29), it does not have prospective purposes but only explanatory ones. The authors' findings are interesting for researchers because they offer original insights on public audit in Europe and cover matters of current interest such as environment, transparency or gender equality.

The research is also of interest for public auditors because it offers them information that may help them improve their activity and find institutional synergies, as the dataset is available to public auditors.

From a social view point, the paper shows that public auditors perform work on topics of interest for the citizens.

The dataset compiled for the research offers extensive data and a wide variety of attributes defining European SAIs and may offer future opportunities for research from different perspectives.

The paper aims to estimate the capacity of supreme audit institutions’ (SAIs) audits to deter potentially wasteful year-end procurement spending. It also studies heterogeneous responses to SAIs’ audits depending on whether agencies’ top managers are appointed through a competitive procedure or not.

A letter signed by the head of Chile’s SAI was sent to a hundred randomly chosen agencies two weeks before the end of the fiscal year, with instructions on year-end spending accounting and an audit threat. In addition, a hundred agencies that did not receive the letter were used as a control group.

Agencies that received the letter reduced year-end aggregate procurement spending by 33% relative to controls. Purchases of office supplies, safety equipment, personal care products and paper products experienced the most considerable reductions. The decrease in year-end spending was smaller for agencies with at least one top manager appointed through a competitive procedure.

A SAI’s audit threat significantly reduced year-end procurement spending. Larger reductions in agencies headed by political appointees and across categories of goods that have been flagged as likely to be purchased to exhaust the budget suggest the avoided expenditures would have been wasteful. Further research is needed to determine if the net social value of year-end procurement spending deterred by SAIs audits is negative as suggested.

This paper has implications for the institutional support of SAIs audits and civil service.

This paper provides novel experimental evidence of SAIs’ audits’ deterrence power on public agencies’ year-end procurement spending.

Since the 1970s the Supreme Audit Institutions (SAI) have gradually expanded their role as external controllers of the public administration. Instead of merely controlling whether accounts are according to standards they have taken on a role as evaluators with a mandate to assess whether the public administration works economically, efficiently and effectively. With this new regime of external control, the question arises whether the SAIs’ control, in practice, contributes to a more efficient and effective public sector. Whether this external control will be effective depends, in the end, on the extent to which the organisations learn from the control they are subjected to and make actual changes. The chapter uses theories of cultural differences and theories on control within public administration to understand civil servant perceptions of SAI results. Data on civil servants’ reactions to the SAIs’ performance audit in four countries are analysed to see whether performance audits have any impact on the audited entities. The research is based on 696 responses to questionnaires sent out to civil servants in three different Nordic countries plus one new democracy in northern Europe, Estonia.

Three decades ago, the National Audit Office (NAO) in the UK acquired the powers to evaluate the extent that the British Administration was managed with economy, efficiency and effectiveness. The NAO has since adopted a dual mission: to help Parliament hold government to account and to improve public service. This study aims to investigate value-for-money (VFM) auditors’ internalisation of a dual organisational identity: “obstructive” actions as representatives of a Supreme Audit Institution (SAI) and “enabling good practice”, induced by a will stated in the mission that the NAO authorities have adopted.

The organisational identity held and promoted by VFM auditors working at the NAO was explored in this research project. The authors specifically examined the understanding of those who claim to be serving both Parliament and organisations audited in their quest for performance improvement. The authors prompted the auditors to explain how they manage to reconcile these seemingly incompatible roles, namely, that of guardians and watchdogs who must publicly report gaps noted and that of assistants in government’s learning process. To this end, the authors conducted a field study at the NAO in September 2012 during which 21 auditors were interviewed individually and as part of two discussion groups.

The findings indicate that the auditors interviewed do not perceive a dichotomy in NAO’s double mission, which they believe to be congruent with their audience’s expectations. They draw meaning and usefulness from their role of monitoring the Administration if they believe they have contributed to improve public affairs management. In their view, the singular role of guardian no longer suffices. The authors conclude that VFM auditors’ recently acquired identity of “moderniser” reflects a self-efficacy expectation that prevents them from recognising the apparent paradox within their dual identity and that lets them fantasise about their real influence on the Administration.

Admittedly, the limited number of auditors interviewed and who took part in discussion groups is not conducive to generalisation of the conclusions to all auditors in the NAO or to other SAIs. However, although modest in number, the auditor respondents have accumulated many years of VFM audit practice and have contributed to the production of many reports. The respondents could therefore rightfully speak of their work as VFM auditors and as representatives of an institution such as the NAO.

This study contributes to the debates about the place and role of SAIs in the control environment of Administrations. By soliciting testimonials from the actors working within the NAO, the authors could thus question certain a priori assumptions held by stakeholders in the political and administrative world for whom auditors are mere “watchdogs” of Administrations, and nothing more.

The dual mission that the NAO has adopted (similar to many other SAIs) has been formally and publicly stated. It was therefore worth investigating how experienced auditors such as those interviewed had internalised this mission. The authors argue that this dual mission, perhaps inspired by the managerialist culture that has shaped changes to the British Administration (and many other occidental Administrations) since the early 1980s and that is seemingly encouraged by Government, twists the legislator’s intentions, which are to consider SAIs’ auditors as guardians and watchdogs of Administrations, not as agents of change and improvement.

Previous studies have argued that trust and commitment can create value in cooperative relationships. However, this study observed that, in practice, trust and commitment alone may not ensure value creation in asymmetric relationships. Accordingly, this study aims to investigate the mediating role of specific assets in the effects of trust and commitment on value creation in asymmetric buyer–seller relationships.

Contract manufacturers (CMs) in Asia were sampled to validate the argument proposed by this study. Most Taiwanese CMs are partnered with international brands (original equipment manufacturers [OEMs]) that have stronger bargaining power. This cooperative relationship is characteristically asymmetric. A questionnaire method was applied, and structural equation modeling was performed to verify the proposed hypotheses.

Specific asset investment (SAI) was a crucial mediator that explained the effects of trust and commitment on the relationship value of an asymmetric cooperative relationship. Past studies have claimed that power asymmetry results in an unequal distribution of benefits. Nevertheless, regarding the relationship between CMs and OEMs, the study revealed that relationship value could still be increased once the congruent goals have been achieved by both parties. This finding contradicts past theoretical predictions.

Characteristically asymmetric CMs–OEMs (seller–buyer) relationships cannot be maintained merely through trust and commitment, particularly in the context of power and resource imbalances in which the stronger party often possesses a wider selection of prospective partners. The results of this study suggested that the CM should unilaterally invest in specific assets conducive to a cooperative relationship as an expression of faith in the relationship with the stronger firm, thereby creating opportunities for value cocreation.

The analysis of the relevance of relationship quality in the context of asymmetric cooperative relationships confirmed the mediating influences of SAI on ensuring value creation and the maintenance of the relationships. Relationship value could still be created despite the highly asymmetry power relationship. The CMs’ SAI is the key mechanism for this achievement.

The increasing uptake of performance auditing (PA), which entails both the facilitation and the control of government policies, has seriously challenged state auditors' claims that they are apolitical. This article aims to understand how supreme audit institutions (SAIs) operate to maintain and nurture the political neutrality and legitimacy of their PA.

The authors draw on Suchman's typology on legitimacy (1995) to analyze the PA reports of two countries with a long history of both performance auditing and accusations of political interference, namely Canada and Denmark. Documentary analysis and interview methods are employed.

This study shows how the two SAIs have been pursuing pragmatic, moral and cognitive legitimacy through the professionalization and standardization of both the form and the content of their PA reports. Engaging and maintaining the dialogue with the audited administration, triangulating recognized social science methods, and emphasizing the “public interest” basis of PA reflect some of the tools adopted to navigate the “grey zone” between objective, relevant and politically sensitive audits.

The paper's explorative approach limits the possibility for robust testing of the causal forces impinging on SAIs' choices of legitimation strategies. Nevertheless, variations between the Canadian and Danish SAIs in the strategic use of some legitimacy tools such as the media suggest a difference in the role of Public Accounts Committee in the two countries that can be investigated in future research.

Much research exists questioning the political neutrality of PA, yet there has not been much discussion on how SAIs have been able to develop and preserve the prevalent legitimacy of their PA amid the criticism. More specifically, our research reveals the tendency of both the Canadian and Danish SAIs to strategically underline the “public interest” dimension of their performance audits in an attempt to increase both their legitimacy and political neutrality.

New public management (NPM) has transformed the public sector auditing context, although in quite different ways. Further, investigations into NPM’s impact on public sector auditors and audit institutions have been largely unconnected, with the exception of the critical examination of performance audits. We investigate the question of how public sector auditors’ roles and activities have changed as a result of NPM and later reforms.

We examine and synthesise public sector audit research examining reforms since the year 2000. The research presented considers changes to external and internal public sector audits as well as the development of public sector audit institutions – known as supreme audit institutions (SAIs).

Considerable changes have occurred. Many were influenced by NPM, but others have evolved from the eco-system of accounting, auditing and public sector management. External auditors have responded to an increase in demand for accountability. Additional management and governance techniques have been introduced from the private sector, such as internal auditing and audit committees. NPM has also led to conflicting trends, particularly when governments introduced competition to public sector auditing by contracting out but then chose to centralise to improve accountability. There is also greater international influence now through bodies like the International Organisation of Supreme Audit Institutions (INTOSAI) and similar regional bodies.

NPM reforms and the eco-system have impacted public sector auditing. Sustainability reporting is emerging as an area requiring more auditing attention; auditors also need to continue to develop better ways to communicate with citizens. Further, research into auditing in non-Western nations and emerging technologies is also required, especially where it provides learnings around more valuable audit practices. Empirical evidence is required of the strengths and weaknesses of SAIs’ structural variety.

This paper explores the value of financial statement auditing in the public sector. The study applies theory about auditing from the private sector as well as the public sector to explore ways in which public sector auditing can be expected to be valuable. It shows that there are a number of complementary explanations that can be applied to examine the value of public audit, including agency, signaling, insurance, management control, governance and confirmation explanations. The evidence from research and history is generally consistent with the agency and management control explanations. There is some support for the signaling and insurance explanations, while research evidence suggests that governance has differing impact in the public sector compared to the private. The confirmation hypothesis is also potentially relevant. Reviewing the history of the development of public sector auditing functions shows that at least some developments were consistent with explanations such as agency theory and management control. Auditing in the public sector is an area where more research is valuable. The paper concludes with a discussion of issues for further investigation.