Dirty Environment Research Articles

Development of a Vision Guided Robot Manipulator for Packing Horticultural Produce

The use of robots in horticulture is discussed and it is concluded that industrial manipulators are not well suited to potential horticultural applications. In general they are over specified, especially with respect to accuracy and as a result, too expensive. The commercial uptake of robotic technology would be facilitated by the availability of low cost manipulators with appropriate specifications. In most cases horticultural manipulators require only modest positional accuracy of a few millimetres under the guidance of a vision system. They should be robust, tolerant to dirty and humid environments and be capable of meeting hygiene requirements. A low cost pneumatically activated manipulator incorporating flexible inflatable elements has been developed to meet this specification. The characteristics of the patented flexible actuator (trade name 'Flexator') are examined and modifications made so that they better suit this application. An experimental two degree-of-freedom manipulator has been constructed and its dynamic performance evaluated. A package consisting of a vision system, high level controller, end-effector and the new manipulator have been put together in a demonstration system. Experimentally, error has been recorded as 2·1 mm in the X coordinate and 2·0mm in the Y coordinate with standard deviations of 0·7 and 0·6mm respectively. Vision-guided packing of loose tomatoes into plastic trays of eight has been chosen as the application. This task is performed reliably in about 21s. Although 2·5% of tomatoes were not picked successfully, the system automatically recovered, resulting in all 20 trial packs being correctly filled.

Alumina-alumina and mullite-mullite joining by reaction sintering process

Joining of simple ceramic shapes to form complex ceramic parts can be considered as an alternative route to the difficult and expensive methods associated with fabrication of near-net-shape ceramic components. The ability to reliably joint ceramic parts to form large systems is considered nowadays as a key technology in enhancing the use of ceramics in high temperature structural applications and in dirty environments. However, as has been pointed out elsewhere, the joining of ceramics is not yet a very high developed art. Most scientific and engineering efforts have been devoted to ceramic to metal joining. Alumina and mullite are two oxides ceramics largely considered for functional as well as structural applications. The purpose of the present investigation is to join alumina-alumina and mullite-mullite ceramics through reaction sintering with zircon.

Environmental control of indoor biologic agents

Environmental control of indoor biologic agents

Environmental control of indoor biologic agents

The indoor environment contains unique pollutants, such as environmental tobacco smoke and indoor allergens. In addition, air pollutants may reach higher levels indoors than outdoors, and in some instances may exceed the national standards for outdoor exposure. Nonindustrial indoor settings, such as offices, residences, and vehicles, also have air quality problems. Although the role of occupational air pollutants (organic and inorganic) in causing complaints in the workplace has been clearly documented, the relationship between poor air quality and health complaints is often controversial. The main causes of poor indoor air quality are an inadequate ventilation or fresh air intake, biologic contamination of the indoor environment, and an accumulation of noxious compounds. A list of important indoor air pollutants is shown in Table I. Because indoor allergen concentrations are higher in homes than in public places, a greater effort should be made to control allergens at home. A reason for this difference may be the more aggressive chemical treatment of carpets in public places. However, in some instances high mite, cat, and dog allergen levels have been detected in schools and day care centers. These findings have important implications for families who are practicing allergen avoidance at home because the effort and time spent controlling allergen exposure could be jeopardized by exposure in the school environment.' Studies conducted in schools have demonstrated that carpets contain high levels of a variety of allergens including pollen, cat, dog, food, mite, and mold allergens.2 Carpets in schools and homes are an important reservoir of allergens.

Supervisory generalised predictive control and fault detection for multivariable anaesthesia

S0ingle-input/single-output generalised predictive control (GPC) has been applied successfully to muscle-relaxant anaesthesia in both simulations and clinical trials. This work was extended later to the multivariable case involving simultaneous control of muscle relaxation through EMG measurements, and unconciousness using blood-pressure monitoring in a series of simulation studies. To achieve even higher degrees of automation, a fault detection isolation and accommodation layer has been superimposed on top of the multivariable GPC strategy. The performance of the overall supervisory control scheme has been evaluated in a series of simulation runs on a work station. The results are encouraging in the sense that the algorithm has proved very effective in detecting, diagnosing and eventually compensating for various simulated faults normally encountered in the operating theatre. The experiments used two versions of GPC: the multivariable GPC (using a P-canonical form for the process model) and GPC with feedforward, and were conducted in noise-free and noise-corrupted situations since operating theatres can be electrically dirty environments. The study forms the basis for an experiment protocol which will be followed in clinical trials.

MR Sensor for Magnetic Encoder

Recent work on magnetoresistive elements for use in magnetic encoders is reviewed. Magnetic encoders are often used as position and speed detectors in motor control systems. They have attracted attention because of their durability in dirty environments, their low temperature dependence, excellent shock resistance, and compatibility with a wide variety of designs. Much of the current work on such detectors aims at high resolution using smaller equipment. In studying suitable constructions for such detectors, the magnetoresistive elements must be considered.

An Intelligent Ultrasonic Sensor for Ranging in an Industrial Distributed Control System

Abstract In this paper, an intelligent instrument for ranging purposes is described. It is based on the precise determination of the time of flight (TOF) of an ultrasonic pulse to evaluate the distance from an object. Ultrasonic sensors offer high reliability, wide measurement ranges, reduced sensitivity to EM noise, and the ability to operate in dusty and dirty environments. This instrument uses digital signal processing techniques in order to improve the accuracy of the measurements and to increase its capabilities. The digital signal processing is managed by an 8-bit microcontroller. The communication tasks through a fault-tolerant real-time LAN, are carried out by an specific processor in order to discharge the main processor.

Advanced sensor systems for theapplication of LIME technologies in the process industry: a review

Modern computer-integrated manufacturing and engineering (CIME) technologieshave been developed and implemented to improve plant and process design, measurement and control design, and plant operation, together with the economic optimization of flow processes. Almost irrespective of which approach is selected for obtaining these results, success or otherwise is based on some process measurements, involving predominantly either temperature, pressure or flow. Optical sensors are often being adopted for these tasks not only because of their non-intrusive nature, but also in view of their reliability, together with their high response speed, intrinsic resolution and increasing ruggedness. In addition, the development of new measurement capabilities such as easy adjustment for operating range, compensation for effects of environmental conditions and self-diagnosis, has given a considerable level of “ intelligence” to current sensors, which are smarter, smaller and cheaper than ever before. This paper reviews and discusses the implementation of advanced sensor systems for onlinemeasurements of process streams with emphasis on hot, dirty, hostile and multiphase environments. The requirements for the integration of the information from the sensors in a CIME environment are considered, taking into account the different levels of automation of typical processes. Novel methodologies, such as fiber-optic sensors, semiconductor materials, image processing and data analysis are discussed, as well as the use of "intelligent" instruments as part of the push towards higher quality.

The State of the Art in the Measurement of Slurries

Abstract In the extraction or beneficiation of valuable minerals and metals, the ore is often finely ground before being treated by an extraction process such as leaching or a beneficiation process such as flotation. Wet grinding produces a slurry in which the concentration of solid particles represents up to 60 per cent of the mass. Since most of the particles are between 20 and 300 μm in diameter, such slurries are often very abrasive and unhomogeneous, and the particles settle out in containers and pipelines if the mixing energy is not sufficiently high to maintain the suspension. Various properties of slurries in such abrasive and dirty environments need to be measured, including flow, density, particle size, elemental or mineral composition, and reagent concentration. This paper discusses the problems encountered in such measurement, gives experimental results, and proposes solutions to some of the existing problems. In addition, it provides an overview of present-day technology, and mentions the requirements for future sensors to be used in the control of mineral-processing operations. In particular, the paper presents analyses of the performance of magnetic flowmeters, Doppler-based ultrasound flowmeters, and other devices used in the determination of flows in mineral slurries. The use of ultrasound and laser-based meters in the on-line determination of particle size are discussed, and new applications for particle - size analysers are highlighted. The direct determination of density in vessels by the use of ultrasound is described. On-line elemental analysis by X-ray fluorescence and the determination of mineral species by X-ray diffraction are addressed, together with their use in process control. Reagent concentration sensors based on oxide or metal electrodes are shown to be useful as indicators of leaching efficiency when they are used in slurry systems.

Husbandry methods predisposing to production diseases in dairy cows.

Errors in management, other than nutrition, which can be predisposing causes of disease, eg, walking on abrasive surfaces and prolonged standing in slurry (which precipitate lameness), faulty milking and a dirty environment (which are conducive to mastitis), breeding to produce oversized fetuses (leading to dystocia) and inefficient observation (leading to a failure to detect oestrus) are described. Nutritional factors affecting conception rates and the occurrence of the metabolic diseases, ketosis, hypocalcaemia and hypomagnesaemia are outlined.

A large aperture spectrometer for observation of final states in electroproduction

The LAME (Large Aperture Magnet Experiment) apparatus, a 22 000 wire magnetic detector built to study final states produced in hydrogen by the 12 GeV electron beam at the Cornell Wilson Synchrotron is described in detail. The following topics are discussed: (a) preparation of the beam, including monitoring techniques; (b) construction of the multi-wire proportional chambers having a m9nimal frame size and the ability to cope with the electron beam which passes through the apparatus; (c) design of the data acquisition system, necessarily large and cheap; (d) track finding; and (e) geometric reconstruction. The last two tasks, the track finding and reconstruction, had to deal with tracks formed in a significantly non-uniform magnetic field and in the dirty environment typical of an electron machine, and indeed were carried out with a very modest computer.

Hepatic drug metabolism in rats: impairment in a dirty environment.

Reduction of aniline hydroxylase activity, ethylmorphine N-dementhylase activity, and cytochrome P-450 content occurred in hepatic microsomes of rats kept under dirty conditions, defined as accumulation for 1 week of urine and feces in pans under the wire mesh cages. In comparison with rats that had urine and feces removed twice daily from such pans, rats kept over Kimpak bedding or over Litter Green, changed twice daily, also showed reduced drug-metabolizing activity in hepatic microsomes, but to a lesser degree than the dirty rats. Placement of a filter top on cages for 1 week also decreased drug-metabolizing activity. These experiments suggest that the relative cleanliness of an animal's environment can influence hepatic microsomal drug metabolism.

Review. Technologies for robot grippers in pick and place operations for fresh fruits and vegetables

Robotics has been introduced in industry to replace humans in arduous and repetitive tasks, to reduce labour costs and to ensure consistent quality control of the process. Nowadays robots are cheaper, can work in hostile and dirty environments and they are able to manipulate products at high speed. High speed and reliability and low robot gripper costs are necessary for a profitable pick and place (P&P) process. However, current grippers are not able to handle these products properly because they have uneven shapes, are flexible and irregular, have different textures and are very sensitive to being damaged. This review brings together the requirements and phases used in the process of manipulation, summarises and analyses of the existing, potential and emerging techniques and their possibilities for the manipulation of fresh horticultural products from a detailed study of their characteristics. It considers the difficulties and the lack of engineers to conceive of and implement solutions. Contact grippers with underactuated mechanism and suction cups could be a promising approach for the manipulation of fresh fruit and vegetables. Ongoing study is still necessary on the characteristics and handling requirements of fresh fruit and vegetables in order to design grippers which are suitable for correct manipulation, at high speed, in profitable P&P processes for industrial applications.

Paper 27: Protection against Dirty Environments: Filtration

The sources and types of environmental contamination, and the methods of removal by filtration, centrifugation, etc., are reviewed, with methods of test, filter media, and filter element and case designs.

Nonepidemic infections peculiar to the gravid state.

DILLON writing in this issue emphasizes the importance of group A streptococcal nursery epidemics. His article 1 is timely because such epidemics appear to be less frequent than formerly and we need to be reminded of our obligation to keep nurseries safe. By now we should be well aware of bad bug epidemics caused by group A streptococci, hospital staphylococci, and enteropathogenic Escherichia coli . We would like to think such epidemics occur with less frequency now due to the alertness of pediatricians, good hospital epidemiology, and new methods for control. We should also be aware of water bug infections occurring as outbreaks—the result of dirty nursery environment—mainly by gram-negative bacilli, such as Pseudomonas, Alkaligenes, Flavobacterium , etc. A recent report has even implicated Klebsiella type 25. 2 Dillon's reference to the rising importance of sporadic group B streptococcus infections of the newborn, and Willis and Austin's report 3 of Vibrio fetus