The role of collaboration in the UK green supply chains: an exploratory study of the perspectives of suppliers, logistics and retailers

Many companies around the world have started to realise that working alone will not be sufficient in their move towards a greener supply chain (SC). More specifically, recent UK government regulations on implementing strict CO2 reduction encourage SC operators to work collaboratively, in production and logistics or other operations, to achieve their green objectives. In this research, we look at some underlying factors of SC collaboration, focussing on suppliers, logistics and retailers, for the purpose of improving the environmental sustainability of companies’ SCs. To facilitate our study, we conduct case studies in two overseas supplier companies with the aim of providing a better understanding of how green issues imposed by European and UK customers influence the companies’ actions to meet agreed environmental goals. Based on the initial analysis of the case studies, we develop a conceptual framework which indicates that SC collaboration plays an important role in ensuring companies achieve environmental sustainability of their SCs. Subsequently, staff in middle-management and related roles in sixteen companies operating in the UK are interviewed. This allows us to understand their business practices in terms of SC collaboration with their suppliers and buyers to achieve the goal of CO2 reduction. Finally, drawing upon the information from company reports and websites, a number of UK leading retailers’ actions to reduce CO2 emissions are investigated. We develop a conceptual framework of SC collaboration for environmental sustainability to help companies improve their level of collaboration between suppliers and buyers in terms of meeting their environmental objectives. The proposed framework will serve as a base model for the companies using or considering SC collaboration to achieve their environmental agendas, in line with governmental green regulatory requirements

Exploring Transit Ridership Using Census, Routing & Scheduling, and Stop Characteristic Data

This study develops, analyzes, and a­­­­­pplies transit-system-specific regression tree models that identify and prioritize transit system improvements through analysis and application of ridership, Census, routing and scheduling, and transit stop characteristic data. Regression trees identify and rank independent variables that split dependent variable datasets into meaningful subsets according to significant relationships with independent variable datasets, and regression tree models can be used to identify and prioritize transit system improvements. In this study, ridership datatypes are the dependent variables (i.e., boardings and alightings) and Census, routing and scheduling, and transit stop characteristic datatypes are the independent variables. Data associated with the San Luis Obispo Regional Transit Authority (RTA) is the basis of this study. The literature review for this study identified no other studies that use regression trees to identify and/or prioritize transit system improvements. The analysis method herein can help identify and prioritize improvements to any transit system. The findings of this study may be applicable to other transit systems if assumptions can be made about the similarity of other systems to the San Luis Obispo Regional Transit Authority system. Relationships between transit ridership and independent variables that may be effective predictors of transit ridership are evaluated in this study. Traditional independent variables used to forecast transit ridership include population and employment densities, land use types, income distributions, service frequencies, and transit stop accessibility; other independent variables that may be significant predictors of transit ridership include transit stop amenities, characteristics, and connecting and nearby infrastructure. Ridership data needed for the analysis presented in this study can be obtained from transit agencies. Census data needed for the analysis presented in this study is available through the United States Census Bureau. Routing and scheduling data needed for the analysis presented in this study can be extracted from local transit system schedules. Transit stop characteristic data needed for the analysis presented in this study can be gathered by using a survey instrument during field-visits. The regression tree models developed in this study show a positive relationship in the RTA system between transit ridership and population density (specifically Asian and twenty to twenty-four years old residential population densities), the number of trips serving transit stops, and transit stop characteristics (specifically the presence of a trash can). According to these findings, this study offers recommendations for improvements to RTA’s transit system and marketing and planning strategies. More general conclusions that could be applicable to more transit systems could be drawn if the analysis method used in this study were performed with more and/or larger datasets (e.g., other transit agency, regional, statewide, national, and/or global datasets) comprised of more robust, accurate, and precise datatypes, and this concept is the basis for the future work recommended by this study

Information needs along the journey chain: users’ perspective about bus system

Buses constitute the main public transport mode in most cities of the world. Accessible Bus Systems are defined as systems that are easy to use. However accessible the infrastructure may be, it is unlikely to provide access if people cannot know about it. Therefore it is essential to have comprehensive and accessible information systems which describe the bus systems during all the stages of the journey. There is a widespread understanding amongst researchers that Information Systems can increase the efficiency of the system and that they should be oriented to meet bus users’ needs. However, existing information systems largely ignore the user’s point of view, in special the requirement of the disabled users. This thesis describes a methodology developed to investigate the problem of using information during a journey by bus in real conditions taking into account the (un)familiarity of the area in study and the individual’s previous knowledge of information system. Two main aspects are identified — the “Required Environment Capability” (the physical, social and psychological environment conditions) and the “Individual Capability Provided” (the individual ability in physical, sensorial and cognitive terms) to plan and execute a journey by bus in an unfamiliar environment. Because of the multidisciplinary aspect of the theme this study uses approaches from different fields of research to construct a methodology to understand individual information use. Based on the principles of Single Case Analysis adapted by adding the concept of the Capabilities Model (CM) (which explores interactions between individual and environment), the combined SCA/CM approach was employed to construct the INFOChain experiment. A set of information pieces were developed for the experiment, delivering Accessibility- Issues (AI-type) information in order to help older people to plan and execute different bus journeys in two different cities: London/UK and Brasilia/BR. General results have shown that although the AI-Type of information is considered important by older people, it needs more than simple expositions to actually take advantages of the information and be able to help disabled users

Catalog of selected heavy duty transport energy management models

A catalog of energy management models for heavy duty transport systems powered by diesel engines is presented. The catalog results from a literature survey, supplemented by telephone interviews and mailed questionnaires to discover the major computer models currently used in the transportation industry in the following categories: heavy duty transport systems, which consist of highway (vehicle simulation), marine (ship simulation), rail (locomotive simulation), and pipeline (pumping station simulation); and heavy duty diesel engines, which involve models that match the intake/exhaust system to the engine, fuel efficiency, emissions, combustion chamber shape, fuel injection system, heat transfer, intake/exhaust system, operating performance, and waste heat utilization devices, i.e., turbocharger, bottoming cycle

Synergies and misalignments in lean and green practices: a logistics industry perspective

This paper conducts an exploratory case study-based research in three companies to identify the main synergies and misalignments between Lean and Green in the context of a range of distribution networks operating globally, regionally and domestically. The research strategy applied by this study is exploratory multiple case studies in three companies, particularly in the road transport and logistics sector. Semi-structured interviews with fifteen executives from three companies were conducted to identify activities within logistics operations leading to synergies and misalignment between Lean and Green practices. The outcome of the three cases shows that several improvements can be achieved by the simultaneous adoption of Lean and Green. The study contributes to the literature by extending the research in the logistics sector and providing examples from a wide variety of logistics operations on synergies and misalignments between Lean and Green practices. The findings and outcome of this study are a starting point for further research in the logistics sector

Powertrain Systems for Net-Zero Transport

The transport sector continues to shift towards alternative powertrains, particularly with the UK Government’s announcement to end the sale of petrol and diesel passenger cars by 2030 and increasing support for alternatives. Despite this announcement, the internal combustion continues to play a significant role both in the passenger car market through the use of hybrids and sustainable low carbon fuels, as well as a key role in other sectors such as heavy-duty vehicles and off-highway applications across the globe. Building on the industry-leading IC Engines conference, the 2021 Powertrain Systems for Net-Zero Transport conference (7-8 December 2021, London, UK) focussed on the internal combustion engine’s role in Net-Zero transport as well as covered developments in the wide range of propulsion systems available (electric, fuel cell, sustainable fuels etc) and their associated powertrains. To achieve the net-zero transport across the globe, the life-cycle analysis of future powertrain and energy was also discussed. Powertrain Systems for Net-Zero Transport provided a forum for engine, fuels, e-machine, fuel cell and powertrain experts to look closely at developments in powertrain technology required, to meet the demands of the net-zero future and global competition in all sectors of the road transportation, off-highway and stationary power industries

Development of tunable terahertz quantum cascade wire lasers

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 179-188).For a long time, terahertz (THz) radiation has been of great interest to scientific community because of its spectroscopic and imaging applications based on its unique properties, such as the capabilities to penetrate many materials which are opaque in other frequency range (e.g. packaging, plastics, paints and semiconductors), and spectroscopic signatures of many important materials. In this thesis, a continuously tunable THz wire QC laser, which comprises a QC laser with deep sub-wavelength transverse dimensions, and a movable side object, termed as "plunger", is demonstrated. This deep sub-wavelength cross-section results in a large fraction of mode propagating outside of the laser core (GaAs/A1₀.₁₅Ga₀.₈₅As material system). The frequency tuning is achieved by changing the transverse wave vector, using a plunger made by metal (metal plunger) or silicon (dielectric plunger). When nudged close to the wire laser core, the metal plunger can push modes to the opposite side of the waveguide. Confined by a metal-metal waveguide, the mode is squeezed and the transverse wave vector is increased, resulting in a blue-shifted frequency. In contrast, a silicon plunger can suck the mode out due to its similar refractive index to GaAs/Al₀.₁₅Ga₀.₈₅As material system of laser core. Thus a decreased transverse wave vector results in a redshifted frequency. Although a tuning record of 138GHz (3.6%) was achieved, a discontinuous tuning resulted from a jittering movement of the plungers due to its friction with the guiding system. To solve this problem, an improved plunger based on micro-mechanical system (MEMS) was implemented. This MEMS plunger uses a two-stage folded-beam flexure to isolate the misaligned external actuation. The plunger is attached with the flexure which suspends above a silicon substrate to eliminate friction. Eventually, this MEMS flexure was actuated by a mechanical system which comprised a lever to de-amplify the displacement of a linear mechanical feedthrough. This MEMS plunger enabled a restorable and frictionless movement which led to a continuous tuning range of 330GHz (8.6%) centered at ~3.85 THz. The challenges posted by the weak mode discrimination led to the development of comb-shape connectors which electrically connect the top metal of wire lasers and the side bonding pad. This design can significantly increase the mode discrimination by selectively guiding undesired mode into the lossy bonding pad. This robust design of single mode operation enables the initial lasing at a frequency far below the gain peak, which can potentially increase the tuning range significantly.by Qi Qin.Ph.D

Novel Validation Techniques for Autonomous Vehicles

L'abstract è presente nell'allegato / the abstract is in the attachmen