Safety Control Strategy Research Articles

Antibiotic resistant bacteria survived from UV disinfection: Safety concerns on genes dissemination

Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) are the emerging contaminants leading to a serious worldwide health problem. Although disinfection like ultraviolet (UV) irradiation could remove part of ARB and ARGs, there still are residual ARB and ARGs in the effluent of wastewater treatment plants.Conjugative transfer is main concern of the risk of ARGs and little is known about the effects of UV disinfection on the transfer ability of the non-inactivated ARB in the effluent which will enter the environment. Hence the influences of UV irradiation and reactivation on ARB conjugative transfer ability were studied under laboratory condition, focusing on the survival bacteria from UV irradiation and the reactivated bacteria, as well as their descendants. The experimental results imply that even 1 mJ/cm2 UV disinfection can significantly decrease the conjugative transfer frequency of the survival bacteria. However, viable but not culturable state cells induced by UV can reactivate through both photoreactivation and dark repair and retain the same level of transfer ability as the untreated strains. This finding is essential for re-considering about the post safety of UV irradiated effluent and microbial safety control strategies were required.

Truck active reversing control strategy based on modified particle filter and multi‐sensors environment perception

Due to the limit of the drivers' sight sheltered by the large body and the complexity of driving, heavy-duty trucks usually cause serious reversing traffic accidents. In this study, the authors present a new strategy to settle this problem by using the multi-sensors system, modified unscented particle filter, and an active safety control strategy. First, multi-sensors including binocular cameras, ultrasonic sensors, and laser rangefinders are used to perceive the environmental information to help drivers to decrease the blind area and obtain the distance between obstacles and the truck. Second, a federal information fusion mechanism based on the unscented Kalman filter is used to fuse the information so that the proposed system can eliminate spurious data and improve the robustness. Next, a framework combining low-rank representation with unscented particle filter that is used for target tracking is proposed. Third, a speed control method is introduced to realise the active speed control of a truck. Lastly, the experiment and the results prove that the proposed algorithm has higher accuracy than others. Moreover, the proposed system can not only help drivers decrease the burden while reversing but also increase the active safety ability to reverse, which has great significance for heavy-duty trucks.

A Rear-End Collision Risk Evaluation and Control Scheme Using a Bayesian Network Model

This paper presents a probabilistic decision-making framework for rear-end collision avoidance systems, focusing on modeling the impact of major collision-causing factors on the occurrence of accidents. Decisions on when and how to assist drivers are made using a Bayesian network approach according to collision risk evaluation results, given a prior probabilistic knowledge. The structure of the Bayesian network model is learnt using a K2 algorithm with a practical dataset. To provide adequate response time for drivers, we also predict collision probability in the next monitoring interval using a Kalman filter model. The prediction accuracy is evaluated with different use cases and compared to real scenarios with the obtained dataset. To make our framework more relevant to practical applications, we also discuss the corresponding safety control strategies by classifying collision risk into high and low levels. In addition, the proposed model is evaluated through experiments including simulations and road tests. In the simulations, the algorithms are tested in different scenarios with various configurations of weather conditions, driver response capability, and vehicular dynamics. In order to demonstrate collision avoidance performance, the proposed model is also compared to existing schemes. In the road tests, the algorithm is embedded into an unmanned vehicle with predefined parameters to evaluate the impact of computational complexity on rear-end collision avoidance. Numerical results show that the proposed model provides an accurate estimation for car-following collision risk with a relatively low complexity, taking into account the impacts of vehicle dynamics, driver reaction capacity, and external environment on rear-end collisions.

An investigation of active safety control strategies for improving the lateral stability of car-trailer systems

An investigation of active safety control strategies for improving the lateral stability of car-trailer systems

An investigation of active safety control strategies for improving the lateral stability of car-trailer systems

This paper presents an evaluation of control strategies for improving the lateral stability of car-trailer systems. A linear stability analysis method is proposed for the evaluation. The strategies include active trailer differential braking, active trailer steering and variable geometry approach. A linear 3 degrees of freedom (DOF) yaw-plane car-trailer model is generated for the controllers' design and a nonlinear 21-DOF yaw-roll car-trailer model is developed in CarSim to validate the stability control strategies by means of numerical simulations. To determine the stable motion boundary, eigenvalue analysis is conducted for identifying the vehicle critical speed. The linear quadratic regulator technique is applied to the design of controllers for active trailer braking, active trailer steering and variable geometry strategies. It is revealed that the active trailer braking strategy is feasible and effective for improving the lateral stability of car-trailer systems. Simulation results demonstrate the effectiveness of the linear stability analysis method.

Effect of divalent ions and a polyphosphate on composition, structure, and stiffness of simulated drinking water biofilms

The biofilm chemical and physical properties in engineered systems play an important role in governing pathogen transmission, fouling facilities, and corroding metal surfaces. Here, we investigated how simulated drinking water biofilm chemical composition, structure, and stiffness responded to the common scale control practice of adjusting divalent ions and adding polyphosphate. Magnetomotive optical coherence elastography (MM-OCE), a tool developed for diagnosing diseased tissues, was used to determine biofilm stiffness in this study. MM-OCE, together with atomic force microscopy (AFM), revealed that the biofilms developed from a drinking water source with high divalent ions were stiffer compared to biofilms developed either from the drinking water source with low divalent ions or the water containing a scale inhibitor (a polyphosphate). The higher stiffness of biofilms developed from the water containing high divalent ions was attributed to the high content of calcium carbonate, suggested by biofilm composition examination. In addition, by examining the biofilm structure using optical coherence tomography (OCT), the highest biofilm thickness was found for biofilms developed from the water containing the polyphosphate. Compared to the stiff biofilms developed from the water containing high divalent ions, the soft and thick biofilms developed from the water containing polyphosphate will be expected to have higher detachment under drinking water flow. This study suggested that water chemistry could be used to predict the biofilm properties and subsequently design the microbial safety control strategies.

Cargo blocking failure analysis, simulation, and safety control of transport aircraft with continuous heavy airdrop

This article investigates the cargo’s blocking failure analysis, simulation, and safety control of transport aircraft with continuous heavy airdrop. As the cargos move backward and drop out, the continuous variation of center of gravity for the whole system will deteriorate flight quality dramatically. Furthermore, due to various mechanical reasons, if the cargo is blocked on the delivery channel and the airdrop process is suspended suddenly at this time, the flight safety may be threatened. In view of this, the blocking failure is analyzed based on the aircraft model in this article and then the simulation is completed to show the failure’s impact on aircraft’s flight quality. Next, based on the uncertainty analysis and introduction of interval robust control theory, the safety controller is designed to stable the closed-loop system. The final simulation shows the proposed safety control strategy’s effectiveness.

Use of a Curtius Rearrangement as Part of the Multikilogram Manufacture of a Pyrazine Building Block

Commercial route definition for a glucokinase activator called for a reevaluation of the synthesis and processes used to access multikilogram quantities of 2-amino-5-methylpyrazine. After consideration of different options, a variation of the Curtius rearrangement used by the medicinal chemistry route was selected for further development. The formation of an acyl azide for the Curtius rearrangement required a process safety control strategy to be put in place. The process developed was used to successfully deliver multikilogram quantities of 2-amino-5-methylpyrazine in an overall yield of 68%, starting from 5-methylpyrazine-2-carboxylic acid.

BACTERIOLOGICAL LOAD ASSESSMENT OF JUICE SOLD IN CAFTERIA AND HOTELS IN ARBA MINCH TOWN, GAMO GOFA, SOUTHERN ETHIOPIA.

Fruit juices are the specialized drinks which are rich in vitamins and nutrients that can help prevent common birth defects as well as cancer and also contain enzymes that are essential for digestive process. The study was performed to evaluate the microbiological quality of locally processed juices such as mango and avocado juices from some selected hotels and cafeteria found in Arba Minch town. Four mango and Avocado, total 8 juice samples from two hotels and cafeterias were collected and their microbial load was analyzed in Microbiology laboratory on appropriate media by using serial dilution techniques followed by spread plate techniques. The highest colonies were observed from mango juice sample from cafeteria two and the lowest colony from hotel one are 94 colonies and 0 colony respectively. The mean bacterial count of avocado juice sample was 49500 cfu/ml which was relatively higher than the mean colonies of mango’s juice sample was 15420 cfu/ml. The total mean of bacterial colonies were 63750 cfu/ml from nutrient agar media, 16250 cfu/ml from Manito salt agar and 23250 cfu/ml from Macconkey in case of cafeteria as well as 41250 cfu/ml from nutrient agar media, 22250 cfu/ml from Manito salt agar and 28000 cfu/ml from Macconkey in case of hotels. Their for, juice venders that produce unpasteuralized mango avocado juices would be recommended that preventative measures through food safety control strategies is important.

Safety control strategy for vertebral lamina milling task

Vertebral lamina milling task is one of the high-risk operations in spinal surgeries. The operation is to remove part of vertebral lamina and release the pressure on the spinal nerve. Because many important vessels and nerves are under the vertebral lamina, any incorrect operation may cause irreparable damage to patients. To improve the safety of lamina milling task, a fuzzy force control strategy is proposed in this paper. Primary experiments have been conducted on bone samples from different animals. The results show that, with the fuzzy force control strategy, the bone milling system can recognize all surgery states and halt the tool at the proper location, achieving satisfactory surgery performance.

A new semi-active safety control strategy for high-speed railway vehicles

This paper focuses on the safety of railway vehicles. A new semi-active control strategy is proposed based on the skyhook control theory. In view of the main railway vehicle safety performance indicators, the new control strategy aims at reducing the derailment coefficient of railway vehicles by restraining the lateral vibrations of the bogie and the wheelset. Furthermore, to evaluate the improvement of the safety performance brought about by the new control strategy, a complete railway vehicle model is established using the ADAMS/Rail software package. In further co-simulations, five conventional control methods are compared with the proposed approach under the same conditions. Co-simulation results indicate that the new control strategy is effective in improving the safety performance of railway vehicles.

Impact Safety Control Strategy for the Battery System of an Example Electric Bus

This paper proposes a side impact safety control strategy for the battery system, aiming at defusing the hazards of unacceptable behaviors of the battery system such as high-voltage hazards. Based on some collision identification metrics, a side impact discrimination algorithm and a side impact severity algorithm are developed for electric buses. Based on the study on the time to break for power battery, the side impact discrimination algorithm response time is about 20 ms posing a great challenge to the side impact discrimination algorithm. At the same time, the reliability of the impact safety control strategy developed in this paper is evaluated for other plausible side impact signals generated by finite element analysis. The results verify that the impact safety control strategy exhibits robust performance and is able to trigger a breaking signal for power battery system promptly and accurately.

Identification of maximum road friction coefficient and optimal slip ratio based on road type recognition

The identification of maximum road friction coefficient and optimal slip ratio is crucial to vehicle dynamics and control. However, it is always not easy to identify the maximum road friction coefficient with high robustness and good adaptability to various vehicle operating conditions. The existing investigations on robust identification of maximum road friction coefficient are unsatisfactory. In this paper, an identification approach based on road type recognition is proposed for the robust identification of maximum road friction coefficient and optimal slip ratio. The instantaneous road friction coefficient is estimated through the recursive least square with a forgetting factor method based on the single wheel model, and the estimated road friction coefficient and slip ratio are grouped in a set of samples in a small time interval before the current time, which are updated with time progressing. The current road type is recognized by comparing the samples of the estimated road friction coefficient with the standard road friction coefficient of each typical road, and the minimum statistical error is used as the recognition principle to improve identification robustness. Once the road type is recognized, the maximum road friction coefficient and optimal slip ratio are determined. The numerical simulation tests are conducted on two typical road friction conditions(single-friction and joint-friction) by using CarSim software. The test results show that there is little identification error between the identified maximum road friction coefficient and the pre-set value in CarSim. The proposed identification method has good robustness performance to external disturbances and good adaptability to various vehicle operating conditions and road variations, and the identification results can be used for the adjustment of vehicle active safety control strategies.

Safety Control Strategy Designed by the Visual Guidance System of Urban Underground Space

The visual guidance system aims to convey the environmental information through selecting, handling and integrating the carrier of visual information. Because of the characteristics of underground space itself, its interior defence against calamities is rather complicated. Therefore, hazard prevention has increasingly become the significant project to develop and utilize the underground space in a scientific, reasonable, safe and effective way. From the angle of safety, this paper elaborates the necessity of visual guidance system to prevent and cure the interior underground space, discusses and brings forward the structural strategy based on the safe guidance system of underground space. Besides, it also brings forward the suggestion to enhance the security of interior underground space by making use of the guidance system of underground space in order to improve the special characteristics to prevent and reduce the disasters in it and increase the elasticity of the cities to endure disasters.

Development of a Safety Assessment Tool for Long-Span Bridges

This paper provides a safety assessment tool (SAT) for long-span bridges in China. The authors selected the Sutong Yangtze River Bridge, one of the largest long-span bridges in China, for a case study. Currently, safety assessment of long-span bridges in China is primarily based on human judgment. No effective method exists for estimating the traffic crash risk of long-span bridges under various conditions; this situation creates difficulty in providing effective safety control strategy and developing counter-measures. In this study, the Traffic Software Integrated System was used to simulate the traffic on the Sutong Bridge. A safety assessment model (SAM) was developed from four contributing factors: traffic volume, free-flow speed, percentage of heavy vehicles, and weather conditions. SAM was used as the basis for developing an SAT that could aid policy makers and traffic professionals in better understanding of traffic safety of the Sutong Bridge: (a) a risk map was created to indicate different safety levels of the bridge under various conditions and (b) a user interface was designed to allow users to identify the safety level of the bridge quickly and easily.

Direct manipulation of tool-like masters for controlling a master-slave surgical robotic system

Robotic-assisted minimally invasive surgery (MIS) can benefit both patients and surgeons. However, the learning curve for robotically assisted procedures can be long and the total system costs are high. Therefore, there is considerable interest in new methods and lower cost controllers for a surgical robotic system. In this study, a knife-master and a forceps-master, shaped similarly to a surgical knife and forceps, were developed as input devices for control of a master-slave surgical robotic system. In addition, a safety strategy was developed to eliminate the master-slave orientation difference and stabilize the surgical system. Master-slave tracking experiments and a ring-and-bar experiment showed that the safety tracking strategy could ensure that the robot system moved stably without any tremor in the tracking motion. Subjects could manipulate the surgical tool to achieve the master-slave operation with less training compared to a mechanical master. Direct manipulation of the small, light and low-cost surgical tools to control a robotic system is a possible operating mode. Surgeons can operate the robotic system in their own familiar way, without long training. The main potential safety issues can be solved by the proposed safety control strategy.

A massage robot based on Chinese massage therapy

PurposeAs Chinese massage is increasingly popular, many physicians are needed these days. In order to promote the experience and skills of experts and reduce labour intensity during massage, a massage robot, which could reproduce the expert techniques with individualized manipulation parameters and enhanced safety control strategies, is presented in this paper.Design/methodology/approachThe kinematic and force features of key massage techniques, such as Thumb Kneading, Pressing, Rolling, Vibrating and Pinching, are summarized by analyzing the massage processes of expert physicians, and a mathematical model for robotic massage is established. With safety issues taken into account, the overall system structure of the massage robot is proposed. The system generally consists of a positioning platform and a massage end‐effector which implements the massage techniques, and the end‐effector is further divided into a parallel mechanism and a massage hand to accommodate different techniques. Visual tracking is used for positioning acupuncture points by recognizing markers on a massage vest worn by the patient. A pain threshold value is introduced to individualize therapy schemes and a force‐position control method based on the pain threshold is presented.FindingsVAS (Visual Analogue Scale) tests for lumbar muscle strain are carried out using the massage robot, and the treatment effect of the massage robot based on traditional Chinese massage therapy theory is initially validated.Research limitations/implicationsThe treatment effect of the massage robot needs to be assessed clinically for more occasions and more clinical experiments will be conducted, to optimize the configuration and control strategy to meet the clinical needs in future work.Originality/valueThe robotic massage system presented in this paper is acting on acupuncture points based on traditional Chinese massage therapy theory, with human manipulation techniques reproduced and expert experiences incorporated. The massage robot can take the place of a massager to perform Chinese massage. Most of the massage robotic systems published in the world perform only one massage technique and the whole massage process is not completely considered. By comparison, the authors' massage robot could perform five techniques. Furthermore, the authors have designed the procedure of robotic massage specifically for patients who suffer from lumbar muscle strain.

Prevalence, characterization and sources of Listeria monocytogenes in blue crab (Callinectus sapidus) meat and blue crab processing plants

Seven blue crab processing plants were sampled to determine the prevalence and sources of Listeria spp. and Listeria monocytogenes for two years (2006–2007). A total of 488 raw crabs, 624 cooked crab meat (crab meat) and 624 environmental samples were tested by standard methods. Presumptive Listeria spp. were isolated from 19.5% of raw crabs, 10.8% of crab meat, and 69.5% of environmental samples. L. monocytogenes was isolated from 4.5% of raw crabs, 0.2% of crab meat, and 2.1% of environmental samples. Ninety-seven percent of the isolates were resistant to at least one of the ten antibiotics tested. Eight different serotypes were found among 76 L. monocytogenes isolates tested with the most common being 4b, 1/2b and 1/2a. Automated EcoRI ribotyping differentiated 11 ribotypes among the 106 L. monocytogenes isolates. Based on ribotyping analysis, the distribution of the ribotypes in each processing plant had a unique contamination pattern. A total of 92 ApaI and 88 AscI pulsotypes among the 106 L. monocytogenes isolates were found and distinct pulsotypes were observed in raw crab, crab meat and environmental samples. Ribotypes and serotypes recovered from crab processing plants included subtypes that have been associated with listeriosis cases in other food outbreaks. Our findings suggest that molecular methods may provide critical information about sources of L. monocytogenes in crab processing plants and will augment efforts to improve food safety control strategies such as targeting specific sources of contamination and use of aggressive detergents prior to sanitizing.

Traffic condition recognition using the [formula omitted]-means clustering method

This paper presents a methodological approach to traffic condition recognition, based on driving segment clustering. Traffic condition recognition has many applications to various areas, such as intelligent transportation, adaptive cruise control, pollutant emissions dispersion, safety, and intelligent control strategies in hybrid electric vehicles. This study focuses on the application of driving condition recognition to the intelligent control of hybrid electric vehicles. For this purpose, driving features are identified and used for driving segment clustering, using the k-means clustering algorithm. Many combinations of driving features and different numbers of clusters are evaluated, in order to achieve the best traffic condition recognition results. The results demonstrate that traffic conditions can be correctly recognized in 87 percent of situations using the proposed approach.

Safety factor analysis and precaution of elderly alimentary tract hemorrhage patients

Objective To analyze unsafely factors of elderly alimentary tract hemorrhage patients,strengthen nursing safety, assure nursing quality, improve patients' satisfaction and avoid adverse events happen to our bestMethods 223 elderly alimentary tract hemorrhage were collected from January to December in 2009, and safety factors, corresponding precaution have been made meanwhile.Days in hospital, recurrence of bleeding and passing rate of basic nursing and satisfaction rate of and incident of safety problems were compared with those 201 peering collected in 2008.Results Of all the physical factors, suffering chronic disease in elderly patients is most and accounts for 85.4%.Of all the psychological factors, low economical status is most and accounts for 54%. Less communication between nurses and and inadequate instruction is most (67%) of environmental and nurse staff factors.Average days in hospital were reduced in 2009 than in 2008 [(9.3 ±0.35)d vs(11.5 ±0.50)d, t =52.887, P ＜0.01].Passing rate,satisfaction rate were improved and bleeding recurrence rate were decreased, compared with those in 2008 (P ＜0.05).Conclusions It will gain better nursing efficacy through analyzing security issue carefully, finding out the disadvantage factor influencing patients' security and adopting effectve nursing safety control strategy. Key words: Elderly; Alimentary tract hemorrhage; Safety factors; Precaution