Sökresultat

Filtyp

Din sökning på "*" gav 531396 sökträffar

Flash temperature analysis method for polymer gears with consideration of deviations in meshing kinematics

The presented work describes a computational method for carrying out a detailed and thorough examination of the flash temperature rise (i.e. the local’instantaneous’ temperature increase on a contact interface, due to frictional effects) present on the tooth flanks of a polymer gear pair, composed of a combination of POM and PA66 thermoplastics, during a given meshing cycle. The method involves a

Conversion model for the design of steel and polymer S-gears

The existing models for the conversion and design of polymer gears are only valid for involute gears. This research was focused on S-gears, a specific type of gear profile which has more favorable contact conditions and greater root thickness when compared to involute gears. S-gears design is currently based on tests, experience, and the use of numerical simulations. Due to the lack of a simple ca

Minimum carbon uptake controls the interannual variability of ecosystem productivity in tropical evergreen forests

Tropical evergreen forests contribute an important part to the interannual variability (IAV) of the global terrestrial gross primary productivity (GPP). Due to its year-round growing-season, high minimum carbon uptake (GPPmin) and dry season greening-up, the key processes driving the GPP variability across seasonal to interannual scale are still in debate. Here, we analyzed the time-series of FLUX

Habitat preferences of male corn buntings emberiza calandra in North-Eastern Germany

Agricultural ecosystems have faced dramatic changes during past decades, resulting in a dramatic loss of farmland biodiversity. The Corn Bunting Emberiza calandra is considered a suitable indicator for the conservation value of farmland habitats, and has recently suffered strong declines throughout much of its European range. As a basis for targeted conservation measures, we investigated the habit

Widespread reduction in sun-induced fluorescence from the Amazon during the 2015/2016 El Niño

The tropical carbon balance dominates year-to-year variations in the CO2 exchange with the atmosphere through photosynthesis, respiration and fires. Because of its high correlation with gross primary productivity (GPP), observations of sun-induced fluorescence (SIF) are of great interest. We developed a new remotely sensed SIF product with improved signal-to-noise in the tropics, and use it here t

An investigation on the potential of bio-based polymers for use in polymer gear transmissions

The potential for replacing the fossil-based Polyoxymethylene (POM) and Polyamide 66 (PA 66) in polymer gear applications with a bio-based Polyamide 6.10 (PA 6.10) was studied and is presented in the article. The use of bio-based plastics is increasing but mostly in undemanding applications like packaging. High-performance plastics are needed in polymer gear transmissions since their operational c

Concurrent Engineering in Machinery

Application of concurrent engineering (CE) to machinery has to consider the type of production (individual, serial), product complexity and level of design. Product development (PD) involves four characteristic levels of design that requires specific activities. The characteristic design levels require definitions of the activities for providing the necessary software and other support for all pha

A Framework for Sustainable Planning and Decision-Making on Resource Recovery from Wastewater: Showcase for São Paulo Megacity

Currently, it is important to develop strategic frameworks to support the selection of sustainable resource recovery solutions. This study applies a new framework for planning, implementation, and assessment of resource recovery strategies for a full-scale wastewater treatment plant (WWTP) in São Paulo megacity. The framework comprises several steps based on case study-specific data and informatio

Responding to funding scarcity : governance challenges in Swedish and South African development partnerships

Purpose: In the context of the general funding scarcity in the nonprofit sector, this paper aims to inquire into the governance challenges facing nonprofit aid organizations in a donor–recipient partner relationship. In particular, the authors focus on the challenges of commercial diversification as the espoused alternative to aid-funding. Design/methodology/approach: A qualitative design was depl

Balls rolling down a playground slide : What factors influence their motion?

Take a selection of balls and marbles along to a nearby playground slide and let students investigate factors that may influence how balls accelerate down an inclined plane. Students can make hypotheses in small groups, plan investigations to test multiple possible explanations and draw conclusions about the importance of different variables. The experiments illustrate the principle of equivalence

Navigating the biblical mandate : Discursive change and adaptation in the International Christian Embassy in Jerusalem

Since its inception in 1980, the International Christian Embassy Jerusalem (ICEJ) has developed into a central player in the formation of Christian Zionism globally. It is known through its high profile in Israeli society, its financial, moral and political support for the State of Israel and its controversial mix of theology and politics. This article focuses on ICEJ's ideological and theological

Influence of manufacturing error tolerances on contact pressure in gears

Gear manufacturing always results in some degree of manufacturing errors, i.e. deviations from the desired gear geometry. These errors alter how the gears mesh, typically causing increased contact pressure which in turn shortens service life. It is therefore crucial to choose tolerances such that excessive contact pressure, and especially tip contact, is avoided. With increasing demands due to ele

Changes in numbers of staging and wintering geese in Sweden : 1977/78-2019/20

Regular goose counts made throughout Sweden since 1977/78 show that the total numbers staging and wintering in the country have increased markedly over the decades. October totals were of 51,000 geese in 1977, rising to c. 600,000 in 2018, during which time January totals also increased from 31,000 to 252,000 birds. The greatest change recorded was for the Greylag Goose Anser anser, numbers of whi

Clinical supervisors’ experiences of midwifery students’ reflective writing : a process for mutual professional growth

Structured reflective writing during clinical placement has been shown to be valuable for students’ learning and for their personal and professional development. The aim of this study was to examine clinical supervisors’ experiences of midwifery students’ daily written reflections on their practice at birthing units. A qualitative study was performed, and data were analysed using content analysis.

The rise of sustainability in Italian wineries: key dimensions and practices

Previous studies on sustainability support the idea that the introduction of specific projects and certifications on sustainability increase the quality of wine production while specific requirements enhance environmental biodiversity and efficiency considering several aspects, such as water consumption and fertilizer use. These studies are mainly based on case studies and focus in particular on t