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1.
From a Waste Cemetery to a Waste Hospital: Recreating Kisumu City’s Waste Management System
Frankline Otiende Awuor, Michael Oloko, Arvin Lucy Onditi, Stephen Gaya Agong’
American Journal of Environmental Protection. 2020 8 (3). doi: 10.12691/env-8-3-2
Keywords: governance framework, Kisumu city, circular economy, waste resources, recycling, return fund, solid waste management
Context: Background: With the new constitutional dispensation in Kenya, counties, cities and towns are creating and recreating their solid waste management systems. Taking Kisumu as a case, this study assesses the existing solid waste management system and how best to recreate it while giving special emphasis to its system configuration, governance framework and waste economy. Methods: Data was collected through group discussions, in depth interviews, document reviews, observations, and a city wide survey of solid waste generation and management. Results were analysed through content and critical analyses and descriptive statistics. Results and Conclusion: The existing configuration does not ensure service delivery to all while the governance framework is not up to the task at hand. Furthermore, the City’s waste economy fails to capture a number of waste resources but loses them to Kachok dumpsite as wastes. Recommendation: First, to better recreate the City’s solid waste management system, its configuration should be designed to ensure service delivery to all. Then its governance framework and waste economy be recreated to seamlessly and sustainably fit this configuration. Moreover, in order to increase the recovery of value from wastes, sorting at source and return funds should be engrained in the system. Additionally, the involvement of resident associations will help improve governance at the residential level. Finally, for all systems, processes, and facilities, performance standards, regular monitoring and evaluation mechanisms should be established and enforced.
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2.
Design of Superelevation of Highway Curves: An Overview and Distribution Methods
Azad Abdulhafedh
Journal of City and Development. 2019 1 (1). doi: 10.12691/jcd-1-1-6
Keywords: superelevation, banking of highway curves, horizontal alignments, circular curves, spiral curves
Context: Superelevation is the banking of highway horizontal curves to assist the driver by counteracting the lateral acceleration produced by tracking the curve. Superelevation is expressed as a decimal, representing the ratio of the pavement slope to width, and ranging from 0.04 to 0.12. Proper superelevation allows a vehicle to safely turn at high speeds and will make riders comfortable. Centrifugal force is the outward pull on a vehicle traversing a horizontal curve. As a vehicle traverses a horizontal curve, centrifugal force is counter-balanced by the vehicle weight component due to roadway superelevation and by the side friction between tires and surfacing. Excessive centrifugal force may cause considerable lateral movement of the turning vehicle and it may become very hard to stay inside the driving lane. Superelevation and side friction are the two factors that help stabilize a turning vehicle. Inadequate superelevation can cause vehicles to skid as they travel through a curve, resulting in a run-off-road crash.  Trucks and other large vehicles with high centers of mass are more likely to roll over at curves with inadequate superelevation. There are practical limits to the rate of superelevation. High rates create steering problems for drivers traveling at lower speeds, particularly during ice or snow conditions. This paper presents an overview of the concept of highway superelevation, and AASHTO distribution methods that utilize both side friction and superelevation in the design of the highway horizontal alignments.
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3.
3D Printing and a New Way to Synthesize Bio-Based and Biodegradable PLA in Chemistry Education for School Students
Felix Pawlak, Stefan Schwarzer
World Journal of Chemical Education. 2023 11 (3). doi: 10.12691/wjce-11-3-1
Keywords: polycondensation, polylactic acid, plastics, school experiment, 3D printing, circular economy
Context: Plastics are a central part of our everyday lives. One plastic is increasingly finding its way into daily use: polylactic acid (PLA). PLA is being used more and more, as it is an important component (polymer) of bio-based and biodegradable plastic. However, experimental access to plastics for students in school chemistry classes is usually tricky because the syntheses of plastics either are time-consuming or do not provide the intended results. Therefore, an experiment was developed that provides simple and quick access polymers and plastics. With this experiment, school students can independently synthesize polylactic acid in chemistry lessons.
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