New slip control system considering actuator dynamics

A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University's HiL system. The control system is based on closed loop shaping Youla-parameterization method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop

Comparative analysis of forward-facing models vs backward-facing models in powertrain component sizing

Powertrain size optimisation based on vehicle class and usage profile is advantageous for reducing emissions. Backward-facing powertrain models, which incorporate scalable powertrain components, have often been used for this purpose. However, due to their quasi-static nature, backward-facing models give very limited information about the limits of the system and drivability of the vehicle. This makes it difficult for control system development and implementation in hardware-in-the-loop (HIL) test systems. This paper investigates the viability of using forward-facing models in the context of powertrain component sizing optimisation. The vehicle model used in this investigation features a conventional powertrain with an internal combustion engine, clutch, manual transmission, and final drive. Simulations that were carried out have indicated that there is minimal effect on the optimal cost with regards to variations in the driver model sensitivity. This opens up the possibility of using forward-facing models for the purpose of powertrain component sizing

Multi-objective optimisation for battery electric vehicle powertrain topologies

Electric vehicles are becoming more popular in the market. To be competitive, manufacturers need to produce vehicles with a low energy consumption, a good range and an acceptable driving performance. These are dependent on the choice of components and the topology in which they are used. In a conventional gasoline vehicle, the powertrain topology is constrained to a few well-understood layouts; these typically consist of a single engine driving one axle or both axles through a multi-ratio gearbox. With electric vehicles, there is more flexibility, and the design space is relatively unexplored. In this paper, we evaluate several different topologies as follows: a traditional topology using a single electric motor driving a single axle with a fixed gear ratio; a topology using separate motors for the front axle and the rear axle, each with its own fixed gear ratio; a topology using in-wheel motors on a single axle; a four-wheel-drive topology using in-wheel motors on both axes. Multi-objective optimisation techniques are used to find the optimal component sizing for a given requirement set and to investigate the trade-offs between the energy consumption, the powertrain cost and the acceleration performance. The paper concludes with a discussion of the relative merits of the different topologies and their applicability to real-world passenger cars

Infection control consequences – early Staphylococcal Scalded Skin Syndrome or Kawasaki Syndrome?

Childhood exanthemata are caused by a broad spectrum of common pathogens. Many exanthemata initially present very similarly, even though caused by different organisms, ranging from virus to bacteria and their respective toxins. In the majority of cases the diagnosis is only of academic value, since therapy does hardly differ. However, in some cases accurate and prompt diagnosis is paramount, since therapy and appropriate hygiene measures prevent morbidity and mortality. We present a case with two differential diagnoses, Staphylococcal Scalded Skin Syndrome and Kawasaki Syndrome, which demonstrates the importance of considering relatively rare conditions as the cause of a childhood exanthema and discuss differences in therapeutic and infection control management. From an infection control point of view, Staphylococcal Scalded Skin Syndrome is, in contrast to Kawasaki Syndrome, highly transmittable to other paediatric patients via the hands of the staff. Therefore maintaining correct hand hygiene as well as other infection control measures are of importance until the final diagnosis is established

In vitro evaluation of the antimicrobial efficacy of a new silver-triclosan vs a silver collagen-coated polyester vascular graft against methicillin-resistant Staphylococcus aureus

ObjectivesVascular graft infection is a rare but serious complication of vascular reconstructive surgery. This in vitro study investigated the antimicrobial efficacy of a new, silver-triclosan collagen-coated polyester vascular graft compared with a silver collagen-coated polyester vascular graft alone during the first 24 hours.MethodsThe antimicrobial efficacy of the investigated vascular grafts was assessed by performing a time-kill kinetic assay following Clinical and Laboratory Institute Standards-approved guidelines M26-A. For the purpose of the experimental study, the ATCC 33591 strain of methicillin-resistant Staphylococcus aureus (American Type Culture Collection, Manassas, Va) was used. All assays were repeated sixfold. Bacterial survival numbers were obtained at 1, 4, 8, 12, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log10 reduction factor (logRF), according to the approved guideline M26-A.ResultsBoth antimicrobial vascular grafts achieved >3 logRF and fulfilled the efficacy criterion for bactericidal activity but performed differently in their speed of antimicrobial action. The silver-triclosan vascular graft achieved 3.37 logRF after 8 hours, and the silver vascular graft showed a 4.19 logRF after 24 hours. The silver-triclosan graft yielded significantly lower colony-forming units/mL counts after 4 hours compared with the silver graft (4.29 × 104 vs 1.03 × 106; P = .031).ConclusionsBoth antimicrobial collagen-coated polymer vascular grafts showed bactericidal activity against methicillin-resistant Staphylococcus aureus in vitro. Although the silver-triclosan vascular graft showed a faster antimicrobial efficacy, the silver graft exhibited its antimicrobial properties after 24 hours. Which concept will protect an implanted vascular prosthetic graft better from bacterial contamination and subsequent infection needs to be investigated further in in vivo animal and clinical studies.Clinical RelevanceVascular graft infection is a rare but one of the most serious complications of vascular reconstructive surgery. Conservative treatment of prosthetic graft infections is rarely successful and is used only in patients with a high operative risk or apparently limited infection. The most pre-eminent strategy against this severe complication therefore is primary prevention of vascular graft infection. The use of antimicrobial vascular grafts might support prevention of vascular graft infection. Results of a standardized experimental study on the antimicrobial efficacy of the silver-triclosan collagen polyester vascular graft with an identical collagen polyester vascular graft containing silver alone are presented

Microbiological evaluation of different reprocessing methods for cuffed and un-cuffed tracheostomy tubes in home-care and hospital setting

Background: Manufacturers’ recommendations on cleaning of tracheostomy tubes focus on general warning information and non-specific manual cleaning procedures. The aim of this experimental study was to evaluate different reprocessing methods and to determine the mechanical integrity and functionality of tracheostomy tubes following reprocessing. Methods: Sixteen cuffed or un-cuffed tracheostomy tubes obtained from hospital in-patients were reprocessed using one of the following reprocessing methods: a) manual brushing and rinsing with tap water, b) manual brushing followed by disinfection with a glutaraldehyde solution, c) manual brushing followed machine-based cleaning in a dishwasher, and d) manual brushing followed by ultrasound cleaning in a commercially available ultrasound device. Microbial burden of the tubes before and after reprocessing was assessed by measurement of microbial colony-forming units per mL (CFU/mL) of rinsing fluid. After cleaning, tracheostomy tubes were investigated for loss of functionality. Findings: Manual brushing and rinsing with tap water reduced microbial colonization in average by 102 CFU/mL, but with poor reproducibility and reliability. Complete microbial reduction was achieved only with additional chemical or machine-based thermal disinfection. Ultrasound sonification yielded no further microbial reduction after manual brushing. Conclusion: Manual brushing alone will not result in complete eradication of microorganism colonising cuffed or un-cuffed tracheostomy tubes. However, manual cleaning followed by chemical or thermal disinfection may be regarded as safe and reproducible reprocessing method. If a machine-based reprocessing method is used for cuffed tubes, the cuffs’ ventilation hose must be secured in a safe position prior to thermal disinfection

Persistently elevated IgA antibodies to Mycoplasma pneumoniae in patients with internal carotid artery stenosis

Background: It has been suggested that Mycoplasma pneumoniae may play a role in the development of atherosclerosis, but to date this association is still a matter of debate due to conflicting findings