This work presents the development of entropy-elastic gelatin based networks in the form of films or scaffolds. The materials have good prospects for biomedical applications, especially in the context of bone regeneration. Entropy-elastic gelatin based hydrogel films with varying crosslinking densities were prepared with tailored mechanical properties. Gelatin was covalently crosslinked above its sol gel transition, which suppressed the gelatin chain helicity. Hexamethylene diisocyanate (HDI) or ethyl ester lysine diisocyanate (LDI) were applied as chemical crosslinkers, and the reaction was conducted either in dimethyl sulfoxide (DMSO) or water. Amorphous films were prepared as measured by Wide Angle X-ray Scattering (WAXS), with tailorable degrees of swelling (Q: 300-800 vol. %) and wet state Young’s modulus (E: 70 740 kPa). Model reactions showed that the crosslinking reaction resulted in a combination of direct crosslinks (3-13 mol.-%), grafting (5-40 mol.-%), and blending of oligoureas (16-67 mol.-%). The knowledge gained with this bulk material was transferred to the integrated process of foaming and crosslinking to obtain porous 3-D gelatin-based scaffolds. For this purpose, a gelatin solution was foamed in the presence of a surfactant, Saponin, and the resulting foam was fixed by chemical crosslinking with a diisocyanate. The amorphous crosslinked scaffolds were synthesized with varied gelatin and HDI concentrations, and analyzed in the dry state by micro computed tomography (µCT, porosity: 65±11–73±14 vol.-%), and scanning electron microscopy (SEM, pore size: 117±28–166±32 µm). Subsequently, the work focused on the characterization of the gelatin scaffolds in conditions relevant to biomedical applications. Scaffolds showed high water uptake (H: 630-1680 wt.-%) with minimal changes in outer dimension. Since a decreased scaffold pore size (115±47–130±49 µm) was revealed using confocal laser scanning microscopy (CLSM) upon wetting, the form stability could be explained. Shape recoverability was observed after removal of stress when compressing wet scaffolds, while dry scaffolds maintained the compressed shape. This was explained by a reduction of the glass transition temperature upon equilibration with water (dynamic mechanical analysis at varied temperature (DMTA)). The composition dependent compression moduli (Ec: 10 50 kPa) were comparable to the bulk micromechanical Young’s moduli, which were measured by atomic force microscopy (AFM). The hydrolytic degradation profile could be adjusted, and a controlled decrease of mechanical properties was observed. Partially-degraded scaffolds displayed an increase of pore size. This was likely due to the pore wall disintegration during degradation, which caused the pores to merge. The scaffold cytotoxicity and immunologic responses were analyzed. The porous scaffolds enabled proliferation of human dermal fibroblasts within the implants (up to 90 µm depth). Furthermore, indirect eluate tests were carried out with L929 cells to quantify the material cytotoxic response. Here, the effect of the sterilization method (Ethylene oxide sterilization), crosslinker, and surfactant were analyzed. Fully cytocompatible scaffolds were obtained by using LDI as crosslinker and PEO40 PPO20-PEO40 as surfactant. These investigations were accompanied by a study of the endotoxin material contamination. The formation of medical-grade materials was successfully obtained (<0.5 EU/mL) by using low-endotoxin gelatin and performing all synthetic steps in a laminar flow hood. / Diese Arbeit beschreibt die Entwicklung Entropie-elastischer Gelatine-basierter Netzwerke als Filme und Scaffolds. Mögliche Anwendungen für die entwickelten Materialien liegen im biomedizinischen Bereich, insbesondere der Knochenregeneration. Im ersten Schritt der Arbeit wurden Entropie-elastische, Gelatine-basierte Hydrogel-Filme entwickelt, deren mechanische Eigenschaften durch die Veränderung der Quervernetzungsdichte eingestellt werden konnten. Dazu wurde Gelatine in Lösung oberhalb der Gel-Sol-Übergangstemperatur kovalent quervernetzt, wodurch die Ausbildung helikaler Konformationen unterdrückt wurde. Als Quervernetzer wurden Hexamethylendiisocyanat (HDI) oder Lysindiisocyanat ethylester (LDI) verwendet, und die Reaktionen wurden in Dimethylsulfoxid (DMSO) oder Wasser durchgeführt. Weitwinkel Röntgenstreuungs Spektroskopie (WAXS) zeigte, dass die Netzwerke amorph waren. Der Quellungsgrad (Q: 300-800 vol. %) und der Elastizitätsmodul (E: 70 740 kPa) konnten dabei durch die systematische Veränderung der Quervernetzungsdichte eingestellt werden. Die Analyse der Quervernetzungsreaktion durch Modellreaktionen zeigte, dass die Stabilisierung der Hydrogele sowohl auf kovalente Quervernetzungen (3-13 mol.-%) als auch auf Grafting von (5-40 mol.-%) und Verblendung mit Oligoharnstoffen (16-67 mol.-%) zurückgeführt werden kann. Die Erkenntnisse aus dem Umgang mit dem Bulk-Material wurden dann auf einen integrierten Prozess der Verschäumung und chemischen Quervernetzung transferiert, so dass poröse, dreidimensionale Scaffolds erhalten wurden. Dafür wurde eine wässrige Gelatinelösung in Gegenwart eines Tensids, Saponin, verschäumt, und durch chemische Quervernetzung mit einem Diisocyanat zu einem Scaffold fixiert. Die Scaffolds hergestellt mit unterschiedlichen Mengen HDI und Gelatine, wurden im trockenen Zustand mittels Mikro Computertomographie (µCT, Porosität: 65±11–73±14 vol.-%) und Rasterelektronenmikroskopie (SEM, Porengröße: 117±28–166±32) charakterisiert. Anschließend wurden die Scaffolds unter Bedingungen charakterisiert, die für biomedizinische Anwendungen relevant sind. Die Scaffolds nahmen große Mengen Wasser auf (H: 630 1680 wt.-%) bei nur minimalen Änderungen der äußeren Dimensionen. Konfokale Laser Scanning Mikroskopie zeigte, dass die Wasseraufnahme zu einer verminderten Porengröße führte (115±47–130±49 µm), wodurch die Formstabilität erklärbar ist. Eine Formrückstellung der Scaffolds wurde beobachtet, wenn Scaffolds im nassen Zustand komprimiert wurden und dann entlastet wurden, während trockene Proben in der komprimierten Formen blieben (kalte Deformation). Dieses Entropie-elastische Verhalten der nassen Scaffolds konnte durch die Verminderung der Glasübergangstemperatur des Netzwerks nach Wasseraufnahme erklärt werden (DMTA). Die zusammensetzungsabhängigen Kompressionsmoduli (Ec: 10 50 kPa) waren mit den mikromechanischen Young’s moduli vergleichbar, die mittels Rasterkraftmikroskopie (AFM) gemessen wurden. Das hydrolytische Degradationsprofil konnte variiert werden, und während des Abbaus kam es nur zu kontrolliert-graduellen Änderungen der mechanischen Eigenschaften. Während der Degradation konnte ein Anstieg der mittleren Porengröße beobachtet werden, was durch das Verschmelzen von Poren durch den Abbau der Wände erklärt werden kann. Die Endotoxinbelastung und die Zytotoxizität der Scaffolds wurden untersucht. Humane Haut-Fibroblasten wuchsen auf und innerhalb der Scaffolds (bis zu einer Tiefe von 90 µm). Indirekte Eluat-Tests mit L929 Mausfibroblasten wurden genutzt, um die Zytotoxizität der Materialien, insbesondere den Einfluss des Quervernetzertyps und des Tensids, zu bestimmen. Vollständig biokompatible Materialien wurden erzielt, wenn LDI als Quervernetzer und PEO40 PPO20-PEO40 als Tensid verwendet wurden. Durch den Einsatz von Gelatine mit geringem Endotoxin-Gehalt, und die Synthese in einer Sterilarbeitsblank konnten Materialien für medizinische Anwendungen (Endotoxin-Gehalt < 0.5 EU/mL) hergestellt werden.

This work aims towards the development of a modular system for fabrication of monodisperse microgels made of poly(2-oxazoline)s for use in the field of regenerative therapy.

This thesis was made together with Syntronic, a leading design house specializing in advanced productand systems development. One of the major trends in vehicle industry today is the emergence of electricvehicles. One of the main challenges for the electric vehicles is the energy storage capacity whichtogether with powertrain, rolling- and wind resistance losses determines the vehicle range. Therefore,steps are taken in all areas from more efficient electronics to regenerative breaking which have beenwidely adopted, and the hunt for harvesting energy from other areas of the car is on its way. Energydissipated in heat from the shock absorbers can be harvested and some concepts of this have showngood results.The focus of this work was therefore to, based on previous studies, develop and evaluatea new type of shock absorber with integrated energy harvesting.A product development process was used to generate a new or develop a current concept for aregenerative shock absorber. From the product development process a compact hydraulic-electricsystem within the shock absorber were designed and evaluated on its regenerative capabilities with apeak efficiency of 32 percent while also providing an adjustable dampening coefficient. The conceptoffers a compact and affordable design by utilizing a vane pump integrated into the shock absorberpiston.

The current efforts to address global sustainability issues are failing. To avoid the consequences of transgressing the planetary boundaries and simultaneously provide people with the basic needs for human prosperity, we have to overcome a profound challenge. We have to produce economic and social well-being while, at the same time, resolving long-standing environmental problems that threaten our very own existence. To overcome this challenge, new types of values-driven enterprises and innovations that aim to regenerate Earth have to guide global development and decision making.   Therefore, this study investigates a new approach to entrepreneurship called regenerative entrepreneurship, an approach that aims to reframe the meaning and purpose of sustainability by building flourishing socio-ecological systems through innovations and business practices that are regenerative by design. By conducting a multiple case study of regenerative organizations, we have delved into the personal stories of entrepreneurs who, on a daily basis, enact their values to regenerate Earth. Through this, we have answered the question of how regenerative entrepreneurs enact their values to build and maintain regenerative organizations.   The findings suggest that regenerative entrepreneurs enact their values in two ways, proactively and reactively, by constantly aligning and calibrating their values, personally, internally, and externally, making sure that they themselves and all their stakeholders work towards the same vision of regenerating Earth.

我們假設，將scleraxis (Scx)基因轉導入肌腱來源的幹細胞（TDSC），製成TDSC-Scx細胞系。TDSC-Scx會促進肌腱修復。本研究的目的在於探索Scx促進TDSC成肌腱分化的作用，以及TDSC-Scx對肌腱修復的促進作用。 / 使用慢病毒載體將Scx轉導入TDSCs，不含Scx的空載作為對照也轉導入TDSCs，用載體上帶有的抗性基因，殺稻瘟菌素對細胞進行篩選。分別建成TDSC-Scx和TDSC-Mock細胞系。Scx 的表達分別用定量PCR以及免疫螢光在mRNA和蛋白水準進行鑒定。TDSC-Scx成肌腱，成軟骨和成骨方向的分化能力用定量PCR檢驗。用大鼠臏腱視窗損傷模型進行了細胞移植試驗，測試TDSC-Scx對肌腱損傷的修復作用。實驗分為三組：（1）支架組，（2）空載體組，（3）Scx組。在細胞移植後的第二，四，八周，收集正在修復中的肌腱樣品，進行植入細胞的存留狀態，鈣化，組織學和生物力學測驗。 / TDSC-Scx比TDSC-Mock有更強的成肌腱分化能力。但是，在成軟骨-成骨分化方面，沒有結論。在動物試驗，植入的細胞在第二周仍然可見，但自第四周起，就不見了。在第八周，各組均有個別樣品輕微異位鈣化，但各組別間並無顯著差異。在早期，TDSC-Scx組比空載體組和支架組合得來更好的修復肌腱的能力。 / TDSC-Scx可能促進肌腱損傷的早期修復。 / We hypothesized that transduction of tendon-derived stem cell (TDSC) with scleraxis (Scx) might promote its tenogenic differentiation and promote better tendon repair compared to TDSC without Scx transduction. This study thus aimed to investigate the effect of Scx transduction on the tenogenic differentiation of TDSC and the effect of the resulting cell line in the promotion of tendon repair. / TDSCs were transduced with lentivirus-mediated Scx or empty vector and selected by blasticidin. The mRNA and protein expression of Scx were checked by qRT-PCR and Immuno fluorescence, respectively. The expression of different lineage markers were examined by qRT-PCR. A rat patellar tendon window injury model was used. The operated rats were divided into 3 groups: (1) scaffold-only group, (2) TDSC-Mock group and (3) TDSC-Scx group. At week 2, 4 and 8 post-transplantation, the repaired patellar tendon was harvested for ex vivo fluorescent imaging, vivaCT imaging, histology, or biomechanical test. / TDSC-Scx consistently showed higher expression of tendon-related markers compared to TDSC-Mock. However, the effect of Scx transduction on the expression of chondro-osteogenic markers was less conclusive. The transplanted TDSCs could be detected in the window wound at week 2 but not at week 4. Ectopic ossification was detected in some samples at week 8 but there was no difference among different groups. The TDSC-Scx group promoted early tendon repair histologically and biomechanically compared to the scaffold-only group and the TDSC-Mock group. / TDSC-Scx might be used for the promotion of early tendon repair. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Tan, Chunlai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 66-70). / Abstracts also in Chinese. / Chapter Thesis/Assessment Committee --- p.i / Acknowledgment --- p.ii / Publication --- p.vi / Abstract --- p.vii / 摘要 --- p.viii / Chapter Chapter 1 --- Tendon injury and tendon tissue engineering --- p.1 / Chapter 1.1 --- Anatomy of tendon --- p.1 / Chapter 1.2 --- Epidemiology of tendon injury --- p.3 / Chapter 1.3 --- Process and problems of tendon healing --- p.4 / Chapter 1.4 --- Current treatment and cell-based therapy for tendon repair --- p.5 / Chapter 1.5 --- Transcriptional factor Scleraxis and tendon --- p.8 / Chapter 1.5.1 --- Helix-loop-helix (HLH) and bHLH proteins --- p.8 / Chapter 1.5.2 --- Scleraxis --- p.9 / Chapter 1.6 --- Research focus and implications --- p.11 / Chapter 1.7 --- Hypotheses and objectives of this study --- p.12 / Chapter 1.8 --- Clinical significance --- p.13 / Chapter Chapter 2 --- Materials and Methods --- p.14 / Chapter 2.1 --- Study Design --- p.14 / Chapter 2.2 --- Establishment of TDSC-Scx cell line --- p.15 / Chapter 2.2.1 --- Isolation of TDSC and cell culture --- p.15 / Chapter 2.2.2 --- Establishment of TDSC-Scx cell line --- p.17 / Chapter 2.2.2.1 --- Construction of plasmid --- p.17 / Chapter 2.2.2.2 --- Transfection --- p.23 / Chapter 2.2.2.3 --- Infection --- p.24 / Chapter 2.2.2.4 --- Selection --- p.24 / Chapter 2.2.2.5 --- Characterization of TDSC-Scx and TDSC-Mock --- p.25 / Chapter 2.2.2.5.1 --- qRT-PCR --- p.25 / Chapter 2.2.2.5.2 --- Immune-fluorescent (IF) --- p.26 / Chapter 2.2.2.6 --- Lineage marker expression --- p.26 / Chapter 2.2.3 --- Data analysis --- p.29 / Chapter 2.3 --- The effect of TDSC-Scx on healing in a patellar tendon window injury model --- p.30 / Chapter 2.3.1 --- Animal surgery --- p.30 / Chapter 2.3.2 --- Ex Vivo Fluorescence Imaging --- p.32 / Chapter 2.3.3 --- vivaCT --- p.33 / Chapter 2.3.4 --- Histology --- p.33 / Chapter 2.3.5 --- Biomechanical test --- p.35 / Chapter 2.3.6 --- Data analysis --- p.37 / Chapter Chapter 3 --- Results --- p.38 / Chapter 3.1 --- Generation of TDSC-Scx and TDSC-Mock cell lines --- p.38 / Chapter 3.1.1 --- Plasmid --- p.38 / Chapter 3.1.2 --- Cell morphology --- p.38 / Chapter 3.1.3 --- Expression of Scx --- p.38 / Chapter 3.1.4 --- Expression of chondro-/osteo-/tenogenic markers --- p.39 / Chapter 3.2 --- The healing effect of TDSC-Scx on a patella tendon window injury model --- p.40 / Chapter 3.2.1 --- The fate of transplanted cells --- p.40 / Chapter 3.2.2 --- Ossification --- p.40 / Chapter 3.2.3 --- Histology --- p.40 / Chapter 3.2.3.1 --- Fiber arrangement --- p.41 / Chapter 3.2.3.2 --- Cellularity --- p.41 / Chapter 3.2.3.3 --- Cell alignment --- p.42 / Chapter 3.2.3.4 --- Cell rounding --- p.42 / Chapter 3.2.3.5 --- Vascularity --- p.43 / Chapter 3.2.3.6 --- Fiber structure --- p.43 / Chapter 3.2.3.7 --- Hyaline degeneration --- p.43 / Chapter 3.2.3.8 --- Inflammation --- p.44 / Chapter 3.2.3.9 --- Ossification --- p.44 / Chapter 3.2.4 --- Biomechanical properties --- p.44 / Chapter Chapter 4 --- Discussion --- p.55 / Chapter 4.1 --- In vitro --- p.55 / Chapter 4.1.1 --- Scx transduction did not lead to morphological change in TDSCs --- p.55 / Chapter 4.1.2 --- Scx transduction led to higher expression of Scx mRNA --- p.55 / Chapter 4.1.3 --- TDSC-Scx expressed higher levels of tenogenic markers --- p.56 / Chapter 4.2 --- In vivo --- p.58 / Chapter 4.2.1 --- The fate of transplanted cells --- p.58 / Chapter 4.2.2 --- Ossification was vague --- p.58 / Chapter 4.2.3 --- TDSC-Scx promoted tendon healing --- p.58 / Chapter 4.2.4 --- Biomechanical properties --- p.59 / Chapter 4.2.5 --- Clinical consideration --- p.60 / Chapter 4.3 --- Similar studies --- p.61 / Chapter Chapter 5 --- Limitations --- p.63 / Chapter 5.1 --- Direct Scx protein expression and function information unavailable --- p.63 / Chapter 5.2 --- Differentiation assay --- p.64 / Chapter Chapter 6 --- Conclusion --- p.65 / Reference --- p.66 / Appendix --- p.71

Les travaux précédents trouvés dans la littérature ont mis l'importance sur la pile à combustible PEM ou électrolyseur PEM. Certains articles ont étudié également la pile à combustible réversible et le système d'alimentation en hydrogène par énergie solaire en intégrant à la fois la pile à combustible et électrolyseur. Contrairement à un « Unitised regenerative fuel cell (URFC)», notre conception a un compartiment individuel pour chaque système de PEM-Fuel Cell et d'electrolyseur-PEM et nommé Quasi - URFC. Grâce à ce nouveau concept, l'objectif principal est de réduire le coût de la pile à combustible régénératrice (RFC) en minimisant le rapport de surface superficielle géométrique du catalyseur de l'assemblage membrane électrodes (AME) des deux modes dans la cellule. D'ailleurs, nous visons également à construire un RFC plus compact, léger et portable par rapport à une pile à combustible ou l'électrolyseur classique. Ce travail de recherche est divisé en trois parties : la modélisation et simulation numérique, l'assemblage du prototype et le travail d'expérimentation. Quant à la partie de modélisation, un modèle physique multi-2D a été développé dans le but d'analyser les performances d'une pile à combustible à régénérée à trois-compartiments, qui se compose d'une piles à combustible et d'électrolyseur. Ce modèle numérique est basée sur la résolution des équations de conservation de masse, du momentum, des espèces et du courant électrique en utilisant une approche par éléments finis sur des grilles 2D . Les simulations permettent le calcul de la vitesse, de la concentration de gaz, la densité de courant et les distributions de potentiels en mode pile à combustible et en mode d'électrolyse, ainsi nous aider à prédire le comportement de quasi - RFC. En outre, l'assemblage du premier prototype du nouveau concept de pile à combustible à combustible régénérée a été achevée et testée au cours des trois années d'études dans le cadre d'une thèse. Les résultats expérimentaux de la 3 Compartiments R-PEMFC ont été prometteurs dans les deux modes, soit en mode piles à combustible et soit en mode d'électrolyseur. Ces résultats valideront ensuite les résultats de la simulation, obtenus auparavant par la modélisation. / The past works found in the literature have focused on either PEM fuel cell or electrolyzer-PEM. Some of the papers even studied the unitised reversible regenerative fuel cell (URFC) and the solar power hydrogen system by integrating both fuel cell and electrolyzer. Unlike the URFC, our design has an individual compartment for each PEMFC and E-PEM systems and named Quasi-URFC. With this new concept, the main objective is to reduce the cost of regenerative fuel cell (RFC) by minimizing the ratio of the catalyst’s geometric surface area of the membrane electrode assembly (MEA) of both cell modes. Apart from that, we also aim to build a compact, light and portable RFC.This research work is divided into three parts: the modeling, assembly of the prototype and the experimentation work. As for the modeling part, a 2D multi-physics model has been developed in order to analyze the performance of a three chamber-regenerative fuel cell, which consists of both fuel cell and electrolyzer systems. This numerical model is based on solving conservation equations of mass, momentum, species and electric current by using a finite-element approach on 2D grids. Simulations allow the calculation of velocity, gas concentration, current density and potential's distributions in fuel cell mode and electrolysis mode, thus help us to predict the behavior of Quasi-RFC. Besides that, the assembly of the first prototype of the new concept of regenerative fuel cell has been completed and tested during the three years of PhD studies. The experimental results of the Three-Chamber RFC are promising in both fuel cell and electrolyzer modes and validate the simulation results that previously obtained by modeling.

This work aims towards the development of a modular system for fabrication of monodisperse microgels made of poly(2-oxazoline)s for use in the field of regenerative therapy.

The melanoma cell adhesion molecule defines mesenchymal stromal cells in the human bone marrow that regenerate bone and establish a hematopoietic microenvironment in vivo. The role of the melanoma cell adhesion molecule in primary human mesenchymal stromal cells and the maintenance of hematopoietic stem and progenitor cells during ex vivo culture has not yet been demonstrated. We applied RNA interference or ectopic overexpression of the melanoma cell adhesion molecule in human mesenchymal stromal cells to evaluate the effect of the melanoma cell adhesion molecule on their proliferation and differentiation as well as its influence on co-cultivated hematopoietic stem and progenitor cells. Knockdown and overexpression of the melanoma cell adhesion molecule affected several characteristics of human mesenchymal stromal cells related to osteogenic differentiation, proliferation, and migration. Furthermore, knockdown of the melanoma cell adhesion molecule in human mesenchymal stromal cells stimulated the proliferation of hematopoietic stem and progenitor cells, and strongly reduced the formation of long-term culture-initiating cells. In contrast, melanoma cell adhesion molecule-overexpressing human mesenchymal stromal cells provided a supportive microenvironment for hematopoietic stem and progenitor cells. Expression of the melanoma cell adhesion molecule increased the adhesion of hematopoietic stem and progenitor cells to human mesenchymal stromal cells and their migration beneath the monolayer of human mesenchymal stromal cells. Our results demonstrate that the expression of the melanoma cell adhesion molecule in human mesenchymal stromal cells determines their fate and regulates the maintenance of hematopoietic stem and progenitor cells through direct cell-cell contact.

The air hybrid engine absorbs the vehicle kinetic energy during braking, stores it in an air tank in the form of compressed air, and reuses it to start the engine and to propel a vehicle during cruising and acceleration. Capturing, storing and reusing this braking energy to achieve stop-start operation and to give additional power can therefore improve fuel economy, particularly in cities and urban areas where the traffic conditions involve many stops and starts. In order to reuse the residual kinetic energy, the vehicle operation consists of 3 basic modes, i.e. Compression Mode (CM), Expander Mode (EM) and normal firing mode, as well as stop-start operation through an air starter. A four-cylinder 2 litre diesel engine has been modelled to operate in four air hybrid engine configurations so that the braking and motoring performance of each configuration could be studied. These air hybrid systems can be constructed with production technologies and incur minimum changes to the existing engine design. The regenerative engine braking and starting capability is realised through the employment of an innovative simple one-way intake system and a production cam profile switching (CPS) mechanism. The hybrid systems will allow the engine to be cranked by the compressed air at moderate pressure without using addition starters or dedicated valves in the cylinder head. Therefore, the proposed air hybrid engine systems can be considered as a cost-effective regenerative hybrid powertrain and can be implemented in vehicles using existing production technologies. A novel cost-effective pneumatic regenerative stop-start hybrid system, Regenerative Engine Braking Device (RegenEBD), for buses and commercial vehicles is presented. RegenEBD is capable of converting kinetic energy into pneumatic energy in the compressed air saved in an air tank using a production engine braking device and other production type automotive components and a proprietary intake system design. The compressed air is then used to drive an air starter to achieve regenerative stop-start operations. The proposed hybrid system can work with the existing vehicle transmission system and can be implemented with the retro-fitted valve actuation device and a sandwich block mounted between the cylinder head and the production intake manifold. Compression mode operation is achieved by keeping the intake valves from fully closed throughout the four-strokes through a production type variable valve exhaust brake (VVEB) device on the intake valves. As a result, the induced air could be compressed through the opening gap of intake valves into the air tank through the intake system of proprietary design. The compressed air can then be used to crank the engine directly through the air expander operation or indirectly through the action of an air starter in production. A single cylinder camless engine has been set up and operated to evaluate the compression mode performance of two air hybrid concepts. The experimental results are then compared with the computational output with excellent agreement. In order to evaluate the potential of the air hybrid engine technologies, a new vehicle driving cycle simulation program has been developed using Matlab Simulink. An air hybrid engine sub-model and methodology for modelling the air hybrid engine’s performance have been proposed and implemented in the vehicle driving cycle simulation. The NEDC analysis of a Ford Mondeo vehicle shows that the vehicle can achieve regenerative stop-start operations throughout the driving cycle when it is powered by a 2.0litre diesel engine with air hybrid operation using a 40litre air tank of less than 10bar pressure. The regenerative stop-start operation can lead to 4.5% fuel saving during the NEDC. Finally, the Millbrook London Transport Bus (MLTB) driving cycle has been used to analyse the effectiveness of RegenEBD on a double deck bus powered by a Yuchai diesel engine. The results show that 90% stop-starts during the MLTB can be accomplished by RegenEBD and that a significant fuel saving of 6.5% can be obtained from the regenerative stop-start operations.

The implementation of an energy recovery system for retreiving otherways wasted energy is an effective method for reducing the overall energy consumption of a mobile machine. In a fork lift, there are two subsystems that can be effectively modified for recovering energy. These are the driveline and the lift/lower function of the mast. This study focuses on the latter by studying a recovery system whose main component is a hydraulic transformer consisting of a hydraulic motor, a variable displacement pump and an induction motor. Since the flow rate/pressure - ratio can be modified, the utilization of the hydraulic transformer enables downsizing of the accumulator volume. However, the decrease of the gas volume leads to an increase in the compression ratio of the accumulator, which in terms leads to higher gas temperatures after charging and consequently to higher thermal losses during holding phase. In order to reduce these losses, a thermally regenerative unit was implemented to the gas volume of an accumulator to reduce the temperature build up during charging. In this study, the effect of improving the thermal characteristics of the accumulator to the efficiency of the whole energy recovery system is investigated by means of measurements.