Operational improvement outcomes through voluntary compliance in road transport operations

Abstract: This paper presents operational improvement outcomes of the Road Transport Management System (RTMS) in South Africa. The RTMS is a voluntary, self-regulation scheme that encourages consignees, consignors and road transport operators toward best practice in road transport. The views of consignors, consignees and road transport operators were surveyed to provide insights into perceptions and outcomes of the RTMS. Respondents indicate improved safety, operational efficiency, profitability, and reduced road crashes as outcomes of the RTMS. The main obstacles to increased certification are a lack of awareness of the RTMS and a poor understanding of the requirements for becoming certified

Weight reduction of a carbon fibre composite wheel

The wheel of a passenger vehicle must be designed to be safe and light. Despite the tremendous potential of carbon fibre as an automotive material due to high strength and low weight, the prevalence of carbon fibre reinforced plastics (CFRPs) in vehicle wheels is limited. Manufacturing and testing CFRP prototypes is expensive. Thus it is advantageous to develop simulation models for composite weight reduction. The simulation models can provide insight into how lighter CFRP wheels can be designed. This study presents the design development of a CFRP wheel for a high-performance roadster; the CFRP wheel is offered by an automotive manufacturer as a high-performance option instead of aluminium wheels. Finite element (FE) simulations were initially conducted assuming an isotropic material. This initial model was used to eliminate stress concentrations and to design and manufacture an initial CFRP wheel. The CFRP wheel weight is 6.8 kg as compared to the original aluminium wheel which weighs 8.1 kg. This initial design passed the dynamic cornering fatigue test (the most stringent strength test for wheels). Thereafter the wheel was instrumented with strain gauges and a bending moment was applied to the hub using a custom-built test rig. The test rig produced a static load equivalent to the dynamic cornering fatigue test (in which the applied bending moment varies sinusoidally). The test rig allowed for the deflection of the load arm to be measured. The comparison of the experimentally measured strains and an FE model which includes the CFRP laminate properties showed good agreement. Two alternative laminate options were simulated using the FE model. These showed both an increase in stiffness and a calculated weight reduction. This study shows that an aluminium wheel for a high-performance roadster can be redesigned using CFRP to be 16% lighter and using a FE model a further 152 g weight reduction is possible (18% weight reduction in total when compared to the aluminium wheel)

Guidelines for the use of flow cytometry and cell sorting in immunological studies

International audienceThe classical model of hematopoiesis established in the mouse postulates that lymphoid cells originate from a founder population of common lymphoid progenitors. Here, using a modeling approach in humanized mice, we showed that human lymphoid development stemmed from distinct populations of CD127(-) and CD127(+) early lymphoid progenitors (ELPs). Combining molecular analyses with in vitro and in vivo functional assays, we demonstrated that CD127(-) and CD127(+) ELPs emerged independently from lympho-mono-dendritic progenitors, responded differently to Notch1 signals, underwent divergent modes of lineage restriction, and displayed both common and specific differentiation potentials. Whereas CD127(-) ELPs comprised precursors of T cells, marginal zone B cells, and natural killer (NK) and innate lymphoid cells (ILCs), CD127(+) ELPs supported production of all NK cell, ILC, and B cell populations but lacked T potential. On the basis of these results, we propose a "two-family" model of human lymphoid development that differs from the prevailing model of hematopoiesis