1,720,958 research outputs found
Review of studies on outdoor thermal comfort in warm humid climates : challenges of informal urban fabric
No full textIn warm humid climate regions where majority of the population spend most of the time outdoors, an adequate outdoor thermal environment is crucial. A number of studies on outdoor thermal comfort in warm humid climates were carried out in the past decade. However, most of these studies focused on the formal urban fabric and left the informal urban fabric, where typically 30 to 85% of the population in developing countries resides, unattended. Theoretically, the informal urban fabric structure of towns/cities poses many outdoor thermal environmental challenges, such as lack of air movement, high thermal stress and discomfort. This paper reviews previous research on outdoor thermal comfort in warm humid climates, and, particularly, it focuses on the relationship between outdoor thermal comfort and urban fabric as well as human thermal perception. Regarding the formal urban fabric, this review asserts that the thermal comfort range is higher in warm humid climates than in temperate climates and that thermal indices alone cannot predict thermal comfort; behavioural and psychological adaptation have proven to have a big impact on thermal perception. As for the informal urban fabric, only few studies have investigated the influence of the urban geometry and none has studied people’s thermal perception of the outdoor thermal environment. To conclude, the article highlights practical challenges posed by the informal urban fabric in contrast to the formal urban fabric in terms of structure (morphology)
Spatial and temporal variations of microclimate and outdoor thermal comfort in informal settlements of warm humid Dar es Salaam, Tanzania [Elektronisk resurs]
No full textIn developing countries, urbanization is dominated by the growth of informal settlements which represents 40–80% of major cities. The challenges brought up by the growth of informal settlements spans from social-economic to environmental. Previously, upgrading of the informal settlements focused on social-economic aspects such as provision of necessary services for the residents, whereas the quality of the outdoor thermal environment has not received much attention. This paper entails to investigate the potential of upgrading the outdoor thermal environment in informal settlements in the warm humid city of Dar es Salaam, Tanzania through examining the influence of addition of trees with different Leaf Area Index (LAI) and incremental increase of buildings heights. The study uses simulation as a method for analysis of the warm season and calculates the Physiological Equivalent Temperature (PET) as a thermal index. Results show substantial improvement of both microclimate and outdoor thermal comfort. Incremental increase of buildings heights in a street canyon to 12, 18, and 24 m leads to the reduction of PET by 2.5, 2.8, and 3.8 °C respectively at 2:00 p.m. Similarly, applying LAI's of 2, 4, and 6 m2/m2 leads to reduction of the mean radiant temperature by 7.9, 10.1, and 12.2 °C; while PET was reduced by 3.9, 4.7, and 5.6 °C respectively at 2:00 p.m. Nonetheless, upgrading of informal settlements shows marginal influence on the reduction of air temperature. Despite the noted thermal improvement in the studied area, the thermal comfort limits of the warm season were difficult to reach. The findings suggest that addition of vegetation is the economically most effective way for upgrading thermal conditions in informal urban fabric areas
Urbanites’ outdoor thermal comfort in the informal urban fabric of warm-humid Dar es Salaam, Tanzania
No full textIn warm humid tropical climates, the outdoor environment defines the lives of the majority of the population in terms of social and economic aspects. Improvement of the outdoor thermal environment encourages social and economic prosperity of the urbanites. This paper explores urbanites’ thermal comfort in the informal urban fabric of warm humid Dar es Salaam, Tanzania. Simultaneously, the study conducted micrometeorological measurements and a questionnaire survey consisting of 1541 respondents for both the warm and cool seasons. The thermal indices, Standard Effective Temperature (SET*), Universal Thermal Comfort Index (UTCI) and Physiological Equivalent Temperature (PET) were calculated. Results show that urbanites of the informal urban fabric areas experience both narrower and higher thermal comfort ranges when compared to both similar climates and other types of climate in the formal urban fabric context. Thermal acceptable ranges were found to be 30.2−32.5 °C and 23.4−27.4 °C for UTCI and SET* respectively. Despite the fact that the results showed the high adaptive capacity of the urbanites, they also revealed the urbanites’ tolerance to high thermal index temperatures due to the limited adaptive options available within the informal urban fabric morphology. The study findings could contribute significantly to the upgrading of informal settlements
Spatial and temporal variations of microclimate and outdoor thermal comfort in informal settlements of warm humid Dar es Salaam, Tanzania
No full textIn developing countries, urbanization is dominated by the growth of informal settlements which represents 40–80% of major cities. The challenges brought up by the growth of informal settlements spans from social-economic to environmental. Previously, upgrading of the informal settlements focused on social-economic aspects such as provision of necessary services for the residents, whereas the quality of the outdoor thermal environment has not received much attention. This paper entails to investigate the potential of upgrading the outdoor thermal environment in informal settlements in the warm humid city of Dar es Salaam, Tanzania through examining the influence of addition of trees with different Leaf Area Index (LAI) and incremental increase of buildings heights. The study uses simulation as a method for analysis of the warm season and calculates the Physiological Equivalent Temperature (PET) as a thermal index. Results show substantial improvement of both microclimate and outdoor thermal comfort. Incremental increase of buildings heights in a street canyon to 12, 18, and 24 m leads to the reduction of PET by 2.5, 2.8, and 3.8 °C respectively at 2:00 p.m. Similarly, applying LAI's of 2, 4, and 6 m2/m2 leads to reduction of the mean radiant temperature by 7.9, 10.1, and 12.2 °C; while PET was reduced by 3.9, 4.7, and 5.6 °C respectively at 2:00 p.m. Nonetheless, upgrading of informal settlements shows marginal influence on the reduction of air temperature. Despite the noted thermal improvement in the studied area, the thermal comfort limits of the warm season were difficult to reach. The findings suggest that addition of vegetation is the economically most effective way for upgrading thermal conditions in informal urban fabric areas
Evaluating the Economic Impact of Alternative vs. Conventional Construction Materials for Residential Projects in Tanzania: Integrating Environmental and Social Criteria
Full text linkPrevious research in Tanzania has focused on comparing the mechanical and environmental properties of sustainable building materials (SBMs) with those of their conventional counterparts; however, there remain limited contributions in assessing the economic impacts associated with this trend. This significantly hinders the adoption of SBMs in residential construction, as economic viability remains a critical factor in material selection in developing countries, such as Tanzania. Using cost-benefit analysis (CBA), this study addresses this gap by evaluating the economic viability of SBMs in comparison to conventional materials for residential building projects in Tanzania, while considering environmental and social factors. To achieve this aim, a comparative analysis of two material alternatives, namely compressed stabilised earth blocks (CSEBs) and conventional concrete blocks, was conducted based on predefined criteria, including cost, local availability, and ease of use. Findings reveal that CSEB walls are approximately 18% more cost-effective than concrete blocks, offering enhanced constructability and reducing environmental impact, rendering them a highly recommended option for sustainable residential construction. The novelty of this study lies in the application of CBA, which is predicated on developing unit rates per unit scale through a cost breakdown, enabling stakeholders to adjust cost components at a granular level for informed decision-making. Practically, this study provides a cost-based decision-making framework for selecting SBMs in Tanzania while promoting awareness through suggesting an improved format of price list that integrates sustainable alternatives. However, the study is limited by its focus on a specific region and materials, as well as the qualitative treatment of environmental and social criteria. Future research should expand the analysis to include broader aspects, thereby better elucidating the overall suitability of SBMs in diverse contexts
Review of studies on outdoor thermal comfort in warm humid climates [Elektronisk resurs] : challenges of informal urban fabric
No full textIn warm humid climate regions where majority of the population spend most of the time outdoors, an adequate outdoor thermal environment is crucial. A number of studies on outdoor thermal comfort in warm humid climates were carried out in the past decade. However, most of these studies focused on the formal urban fabric and left the informal urban fabric, where typically 30 to 85% of the population in developing countries resides, unattended. Theoretically, the informal urban fabric structure of towns/cities poses many outdoor thermal environmental challenges, such as lack of air movement, high thermal stress and discomfort. This paper reviews previous research on outdoor thermal comfort in warm humid climates, and, particularly, it focuses on the relationship between outdoor thermal comfort and urban fabric as well as human thermal perception. Regarding the formal urban fabric, this review asserts that the thermal comfort range is higher in warm humid climates than in temperate climates and that thermal indices alone cannot predict thermal comfort; behavioural and psychological adaptation have proven to have a big impact on thermal perception. As for the informal urban fabric, only few studies have investigated the influence of the urban geometry and none has studied people’s thermal perception of the outdoor thermal environment. To conclude, the article highlights practical challenges posed by the informal urban fabric in contrast to the formal urban fabric in terms of structure (morphology)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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