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

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

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

Salinity Effects and Salt Movement from Surface Applied Gray Water and Brackish Water

In this paper authors present results of a soil column experiment on salinity effects and salt movement from surface applied gray water and brackish water

The novel application of optimization and charge blended energy management control for component downsizing within a plug-in hybrid electric vehicle

The adoption of Plug-in Hybrid Electric Vehicles (PHEVs) is widely seen as an interim solution for the decarbonization of the transport sector. Within a PHEV, determining the required energy storage capacity of the battery remains one of the primary concerns for vehicle manufacturers and system integrators. This fact is particularly pertinent since the battery constitutes the largest contributor to vehicle mass. Furthermore, the financial cost associated with the procurement, design and integration of battery systems is often cited as one of the main barriers to vehicle commercialization. The ability to integrate the optimization of the energy management control system with the sizing of key PHEV powertrain components presents a significant area of research. Contained within this paper is an optimization study in which a charge blended strategy is used to facilitate the downsizing of the electrical machine, the internal combustion engine and the high voltage battery. An improved Equivalent Consumption Method has been used to manage the optimal power split within the powertrain as the PHEV traverses a range of different drivecycles. For a target CO2 value and drivecycle, results show that this approach can yield significant downsizing opportunities, with cost reductions on the order of 2%–9% being realizable

Antimicrobial efficacy of the combination of chlorhexidine digluconate and dexpanthenol

Objective: The objective of this standardised experimental study was to investigate the antimicrobial efficacy of the combination of chlorhexidine digluconate (CHX) and the anti-inflammatory pro-vitamin dexpanthenol, which stimulates wound-healing, in the form of Bepanthen® Antiseptic Wound Cream, in order to rule out possible antagonistic combination effects of CHX and the alcohol analogue of pantothenic acid (vitamin B5) dexpanthenol. Method: Testing was carried out using the quantitative suspension test at conditions simulating wound bio-burden. Test strains included Enterococcus hirae (ATCC 10541) and Candida albicans (ATCC 10231) in accordance with the standard methods of the German Hygiene and Microbiology Society with the following three organic challenges: i) cell culture medium MEM with Earle’s salts, L-glutamine and 10% foetal calf serum (CCM); ii) 10% sheep’s blood; iii) or a mixture of 4.5% albumin, 4.5% sheep’s blood and 1% mucin. For methodological reasons, the wound cream was tested as a 55% dilution, prepared with 1% Tween 80 (equivalent to a content of 0.275% CHX instead of 0.5% as in the original preparation). CHX 0.275% was tested as control in an aqueous solution and in 1% Tween 80. Additionally, 1% Tween 80 was tested in order to rule out an interfering effect of the dilution medium. A combination of 3% Tween 80, 3% saponin, 0.1% histidine, 0.3% lecithin, 0.5% Na-thiosulphate and 1% ether sulphate was identified as the most appropriate neutraliser during the experiments. Results: Exposed to CCM or 10% sheep’s blood, the tested wound cream fulfilled the requirements for a wound antiseptic against both test species with ≥3 log reduction at 10 minutes. Even at the the worst-case challenge test with 4.5% albumin, 4.5% sheep’s blood and 1% mucin, the requirement for a ≥3 log reduction was met after 24 hours of exposure. Interestingly, the aqueous solution of 0.275% CHX tested as control did not achieve the antimicrobial efficacy of the combination of CHX and 5% dexpanthenol. 1% Tween 80 was ineffective against both test species. Conclusion: Bepanthen® Antiseptic Wound Cream achieves the in vitro bactericidal and fungicidal efficacy required for a wound antiseptic under three different challenges, despite dilution to 55% of the original preparation. So far, the addition of dexpanthenol was intended to support wound healing. However, our results indicate that the antiseptic efficacy of CHX is synergistically increased by adding 5% dexpanthenol. Acknowledging the antimicrobial and residual efficacy of CHX, and bearing in the mind the contraindications to CHX (allergy and anaphylaxis), the tested wound cream should be regarded as better suitable to be used as wound antiseptic than preparations on basis of CHX alon

Bacterial Growth Kinetics under a Novel Flexible Methacrylate Dressing Serving as a Drug Delivery Vehicle for Antiseptics

A flexible methacrylate powder dressing (Altrazeal®) transforms into a wound contour conforming matrix once in contact with wound exudate. We hypothesised that it may also serve as a drug delivery vehicle for antiseptics. The antimicrobial efficacy and influence on bacterial growth kinetics in combination with three antiseptics was investigated in an in vitro porcine wound model. Standardized in vitro wounds were contaminated with Staphylococcus aureus (MRSA; ATCC 33591) and divided into six groups: no dressing (negative control), methacrylate dressing alone, and combinations with application of 0.02% Polyhexamethylene Biguanide (PHMB), 0.4% PHMB, 0.1% PHMB + 0.1% betaine, 7.7 mg/mL Povidone-iodine (PVP-iodine), and 0.1% Octenidine-dihydrochloride (OCT) + 2% phenoxyethanol. Bacterial load per gram tissue was measured over five days. The highest reduction was observed with PVP-iodine at 24 h to log10 1.43 cfu/g, followed by OCT at 48 h to log10 2.41 cfu/g. Whilst 0.02% PHMB resulted in a stable bacterial load over 120 h to log10 4.00 cfu/g over 120 h, 0.1% PHMB + 0.1% betaine inhibited growth during the first 48 h, with slightly increasing bacterial numbers up to log10 5.38 cfu/g at 120 h. These results indicate that this flexible methacrylate dressing can be loaded with various antiseptics serving as drug delivery system. Depending on the selected combination, an individually shaped and controlled antibacterial effect may be achieved using the same type of wound dressing