Pear-shaped lesion of the fossa of Rosenmüller

Retention cyst of the pharyngeal mucosal space is an accumulation of trapped mucous in the mucosa or adenoids of the pharynx. It is a benign lesion, often seen on routine imaging of the head and spine. It is typically a simple cyst originating from the pharyngeal mucosa, without invasion of the surrounding structures. It is important not to misinterpret a retention cyst as a malignant tumor. Patients are usually asymptomatic and do not need treatment

Doing good while making profit: perspectives on reconciling multiple objectives in social enterprises

This dissertation looks at social ventures that create social impact whilst being self-sustainable. By adopting three different theoretical perspectives, various aspects of organizations with multiple social and economic objectives are highlighted. Study 1 examines the hybrid nature of social ventures. It examines the conditions under which social ventures develop hybrid value creating activities to deal with their economic and social goals. Based on data from 11 social ventures, the findings are based on a combination of an inductive analysis and fsQCA analysis. The focal point of the study is how the interplay of the exclusiveness of the beneficiary target group, the overlap between customers and beneficiaries, and the visibility of the social mission in the value offering, influences the extent to which social ventures hybridize their means. The study contributes to the literature on social ventures specifically, and hybrid ventures more generally. Study 2 is based on a qualitative and inductive ethnographic study of a social venture. It sheds light on how organizational members have an imprinting effect on a venture beyond the founding phase. The model proposed in this study illuminates how the imprinting process is an ongoing, two-way interaction between the individual and the organizational level. The analysis shows how the initial imprint of the venture attracts people with specific social identities, and how bottom-up involvement of organizational members impacts on the imprint through three processes: projecting, sharing and contextualizing. This study adds to the literature on imprinting on one hand, and to literature on social ventures on the other hand. Study 3 is a comparative study of two social ventures bringing electrification to rural communities in a bottom-of-the-pyramid market. The study unpacks how these ventures design governance models to align the heterogeneous interests of their stakeholders - including customers, employees and local communities – with their own organizational social and economic objectives. On one hand, the results of the analysis show how the two ventures differ in terms of a customer versus community focus in their governance approach. On the other hand, the analysis shows how this divergent take on governance is driven by a different perception of stakeholder categories, a dissimilar conceptualization of beneficiaries of the social mission, and a different extent of adopting relational versus transactional approaches towards the stakeholders. The study is a response to calls for research on governance in the context of organizations with multiple social and economic objectives.Open Acces

Thin film gauges for the study of heat transfer in spark ignition engines

Knowledge of the in-cylinder heat loss is paramount for further engine development and optimization. This work focuses on the development of the Thin Film Gauge measurement technique for in-cylinder heat flux measurements in a production engine. The sensor’s design and detailed calibration were investigated. Different surfaces of the combustion chamber were instrumented and a heat flux measurement database was conducted. The measurements were used to investigate the heat transfer phenomena and improve the in-cylinder heat transfer modelling, which can lead to more accurate thermodynamic engine simulation codes used to support engine development

Heat transfer in premixed spark ignition engines part I : identification of the factors influencing heat transfer

The heat transfer from the combustion gases to the cylinder walls inside a spark ignition engine is a key factor in an engine's design, due to its influence on the engine's effciency, power and emissions. Therefore a lot of research has been conducted in order to accurately model the heat transfer, for engine design and optimization purposes. These models have been found to provide inaccurate predictions for fuels which have significantly different gas properties compared to traditional fossil fuels. This indicates that the models either do not properly include gas properties, or are missing some important properties in their formulation. In order to construct a general (fuel-independent) heat transfer model, new measurements need to be executed, with multiple fuels that have different properties. Designing such an experiment requires a thorough understanding of the factors influencing the heat transfer and their interactions. In this paper a literature review is presented of heat transfer measurements in spark ignition engines in order to investigate the effect of the engine factors on the heat transfer. Based on this review, a root cause analysis is conducted to identify the independent factors that affect heat transfer. These factors are then used to set up two experiments according to a Design of Experiments methodology that allows the investigation of the effect of different gas properties and engine settings on the heat transfer in a consistent way. The results of these measurements for motored operation are discussed in [1] and for fired operation in a companion paper [2]

MRI diagnosis of carpal boss and comparison with radiography

Background: A carpal boss is a potentially painful bony mass in the region of the second or third carpometacarpal joint. The combination of clinical examination and radiography is usually sufficient for the diagnosis. Purpose: To determine whether magnetic resonance imaging (MRI) examination of the quadrangular joint can assist the diagnosis of persistent pain near a carpal boss. Material and Methods: Fifty-seven patients with a carpal boss were retrospectively reviewed using MRI and conventional radiographs and compared to an asymptomatic control group. Results: MRI demonstrated a variable morphology and a variety of bone and soft tissue abnormalities associated with carpal boss. Bone marrow edema around the quadrangular joint shows a significant correlation (Fisher's exact test: P< 0.001) and a positive correlation (Pearson's test r = 0.632, significant at the 0.01 level [two-tailed]) with a painful carpal boss. Conclusion: MRI offers detailed examination of bone and soft tissue abnormalities associated with a carpal boss. Local bone marrow edema strongly correlates with a painful carpal boss

Local heat flux measurement technique for internal combustion engines

The heat transfer from the combustion gases to the cylinder wall affects the efficiency, emissions and power output of an internal combustion engine. Measuring the heat transfer requires a heat flux sensor inside the combustion chamber that has a short response time and is able to withstand the harsh conditions during combustion. In this work, a suitable sensor is introduced and the measured wall temperature, heat flux and convection coefficient are compared to those measured with a commercial sensor. It was found that both sensors measure the same convection coefficient, but a different wall temperature and heat flux. This is because the presence of the sensor in the combustion chamber wall affects these quantities. A method is proposed to cancel this effect and calculate the actual heat flux through the cylinder wall