Development Engineering最新文献

The combustion of solid fuels in residential cookstoves is a global health and climate issue, and expanded use of improved cookstoves could have significant benefits locally and globally. Evaluating impacts of improved cookstove programs requires more accurately measuring stove use patterns. This work builds on and improves existing stove use monitoring methods. First, we introduce and describe a novel, in-field photo-observation sampling method designed to capture near-continuous, real-world, ground-truth stove usage information. These measurements are used to validate predictions made by electronic stove use monitors (SUMs). Second, we present Cooking Event Detector (CookED), a SUM algorithm that translates stove-temperature measurements into classifications of cooking or not-cooking. The predictive performance of the new algorithm is evaluated using results from the photo-observations and compared to existing algorithms. CookED demonstrates considerable improvement over some methods for all five types of improved and traditional stoves monitored in the study. Overall minute-level predictive accuracy of CookED ranges from 95.6% to 98.4%, depending on the stove type, while Matthews correlation coefficients range from 72.8% to 88.3%. Comparisons between predicted and observed average cooking event durations show high correlation (Pearson's r = 0.85). These methods can be applied in a wide variety of applications, including research studies linking behavior, technology, exposure, and human and environmental health, as well as operational programs that aim to scale up improved cookstove adoption and quantify benefits.

Lighting of pedestrian paths fulfils crucial needs for informal settlement dwellers. A common technological approach in some countries to address these needs is to provide high-mast luminaires. In this paper it is shown by computer simulation that those luminaires are not able to create adequate consistent lighting conditions in common forms of informal settlements. Illuminance uniformity requirements are not met within the entire pedestrian path network. Furthermore, a significant part of the light is emitted on the dwellings’ roof and hence results in light pollution.

Billions of households worldwide cook using biomass fires and suffer from the toxic smoke emitted into their homes. Laboratory studies of wood-burning cookstoves demonstrate that secondary air injection can greatly reduce the emission of harmful air pollution, but these experimental advancements are not easily translated into practical cookstove designs that can be widely adopted. In this study, we use a modular cookstove platform to experimentally quantify the practical secondary air injection design requirements (e.g., flow rate, pressure, and temperature) to reduce mass emissions of particulate matter (PM), carbon monoxide (CO), and black carbon (BC) by at least 90% relative to a traditional cooking fire. Over the course of 111 experimental trials, we illuminate the physical mechanisms that drive emission reductions, and outline fundamental design principles to optimize cookstove performance. Using the experimental data, we demonstrate that low-cost (<$10) fans and blowers are available to drive the secondary flow, and can be independently powered using an inexpensive thermoelectric generator mounted nearby. Furthermore, size-resolved PM measurements show that secondary air injection inhibits particle growth, but the total number of particles generated remains relatively unaffected. We discuss the potential impacts for human health and investigate methods to mitigate the PM formation mechanisms that persist.

Availability, accessibility, affordability, and appropriateness are among several factors that significantly affect the adoption and diffusion of medical devices in low- and middle-income countries. Design processes that promote early and frequent engagement with stakeholders may increase the impact of medical devices aimed at addressing global health challenges by improving the uptake and sustained use of such devices. Prototypes are tools that can be leveraged to engage stakeholders during front-end design to define the problem, elicit requirements, and obtain feedback on early design concepts. Given the lack of literature that examines the practices for stakeholder engagement with prototypes during front-end design, this study was guided by the following research question: How do global health design practitioners approach stakeholder engagement with prototypes during front-end medical device design? Eleven design practitioners from industry were interviewed; transcripts were analyzed using thematic analysis to uncover prototyping behaviors. Transcript level counts of stakeholder groups, prototype forms, and strategies leveraged during stakeholder engagement with prototypes are reported. Based on the analysis of stakeholders, prototypes, and strategies, engagement events that reflect how the global health setting influenced decisions of stakeholder, prototype, and strategy are presented. Participants described challenges associated with: cross-cultural and remote design; the elicitation of contextual requirements; and limited access to resources. Participants devised approaches to overcome these challenges such as: engaging a wide range of stakeholders including proxy users and government stakeholders; developing long-term relationships with community partners; leveraging communication technologies; engaging stakeholders in the real use environment with physical prototypes; using prototypes to bridge the language barrier; ‘polishing’ prototypes; and inviting stakeholders to create and select prototypes. These results could impact approaches to practicing and teaching prototype usage during front-end design in a development setting.

The article analyzes the role of appropriate technologies for mechanization and innovation in small-scale farming in the mountainous and hilly areas of Italy's Piedmont region.

Our approach to appropriate technologies focuses on mountain farmers whose needs have not been met by advances in agricultural mechanization, which have largely served the interests of lowland agribusiness. Mountain farmers’ technological needs were determined using a specific methodology based on an in-depth analysis of the reference target and a field work using an open and inclusive process. The needs thus identified served as the starting point for designing appropriate and intermediate machines. In the conclusions, we present some general implications of appropriate technologies in terms of co-design for development.

This paper proposes a methodology for “design for localisation” that addresses the challenge of designing a product for local manufacture and use, whilst considering the production process availability and the context of the local geographic area. The methodology is derived from a case study of the development of a propeller turbine in Nepal. In the case study, the initial challenge was the absence of a low head turbine that could be manufactured, used and repaired in Nepal. A potential solution from previous academic work was identified however its intended operating environment differed considerably. Through identification of the specific local requirements, the design priorities for individual sub-systems in the new context were developed. Using three examples, design changes driven by improving the ease of manufacture and applicability to the local context are explained. Multiple phases of field and laboratory-based testing were used to validate, adapt and improve the design and its method for implementation. The experiences of the case study lead to three rules for design for localisation using an identified potential solution for a local problem: firstly, to derive local product requirements; secondly to develop solutions appropriate for local manufacturing; and finally, to conduct field-testing phases to ensure the product is suitable for its intended application.