Hose Systems Research Articles

Development of Method for the Measurement of Dermal Exposure on a Lifelike Cow Dummy to Assess the Risk of Using a Urease Inhibitor (Atmowell®) to Reduce NH3 Emissions in Cattle Farming

Up to 58% of NH3 emissions can be reduced through the use of the urease inhibitor Atmowell® in cattle farming. Automated manure scraper and drag hose systems should be used to apply urease inhibitors (UIs) to stable floors. Proof of safe use is also needed. A risk assessment of the urease inhibitor PPDA was conducted utilising estimated and calculated exposure data along with established and verified model calculation tools. Risk assessment models can be improved using measured dermal exposure data. The fluorescent dye pyranine and a Tyvek® collector were used to measure exposure. Tyvek® was attached to a lifelike cow dummy. Regarding the drag hose system, two worst-case scenarios were considered: over the cow and passing the cow. Regarding the robot application system, a 0 m frontal scenario was considered. The over the cow scenario exhibited the highest dermal exposure, with 1.5 mg of PPDA/cow per application run. The robot scenario exhibited the smallest amount, with 0.8 mg of PPDA/cow per application run. The risk of using PPDA was already excluded by model calculation tools in a risk assessment. Compared with the estimated and calculated dermal exposure values, the measured dermal exposure levels were reduced by a factor of two to six.

Организация подачи (транспортировки) огнетушащих веществ на тушение пожаров способом перекачки

Purpose. For the first time ever the article comprehensively considers issues related to water supply (transportation) to the seat of extinguishing large scale fires over long distances. The authors pay special attention to the conditions determining the choice of pumping as a way of supplying water over long distances. Recommendations are given on the choice of water pumping method and its practical implementation at the fire scene. The calculation method of pump and hose systems implemented during pumping and the express method for determining pumping parameters for practical workers are presented. Methods. Based on extinguishing large scale fires data analysis, topical issues on extinguishing agents supply (transportation) by pumping method were identified, analytical calculations of pump-hose systems parameters implemented when pumping water to the seat of extinguishing large scale fires were made, taking into account tactical and technical characteristics of modern fire trucks. Findings. The proposed method (algorithm) allows converting analytical calculations into accurate calculation system (express method) using a spreadsheet or nomograph. For the first time ever the express calculation table shows the dependence of pumping parameters on the distance between the water source and fire source and the water flow rates supplied by fire pressure hoses. This table allows determining the need of water pumping supply to the fire scene and determining the number of pumping stages; number of fire pressure hoses for pumping; pressure on water tenders fire pumps operating in pumping. Express method provides calculation of water pumping parameters from pump to pump via one or two main hose lines. Research application field. Based on this study, the team of authors developed “Recommendations for applying fire departments tactical capabilities at extinguishing fires and conducting emergency rescue operations.” Conclusions. . Knowledge and application of conditions determining the choice of pumping as a method of supplying (transportation) water over long distances, recommendations for choosing a pumping water method, as well as the methodology for calculating hose systems parameters, the number of main fire trucks for supplying fire extinguishing agents to the fire scene by pumping will increase the level of tactical training of the fire chief. The proposed express method for determining the pumping parameters according to the nomograph allows the fire chief and other officials to reduce the time for making managerial decisions and organizing the supply (transportation) of water for fire extinguishment, as well as reduce the area of extinguishing fires and reduce economic and material damage from them.

Снижение рисков при тушении пожаров в суровых климатических условиях

The sustainability of the development of the northern territories of Russia from the Urals to the Pacific Ocean, where the bulk of the country natural resources is concentrated in the twenty-first century, is determined by the integrated approach to planning and managing the risks of using machines, structures and equipment, critical and hazardous industrial facilities and technological support and support at the stages of their operation. Climatic factors have a noticeable effect on increasing the risks of abnormal situations occurrence in emergency situations, for example, on the efficiency of fire departments activity in the winter period of the year and at extinguishing fires in harsh climatic conditions, when water may freeze inside the hoses and in the working chamber of the feed pump. Due to a malfunction in the fire equipment, the scale of the territory covered by the flames can significantly increase, and the extinguishing process will become more complicated. Operability of the hose lines in low temperature conditions is calculated using Methodological Recommendations for ensuring the operability of pump and hose systems of fire trucks when extinguishing fires in the conditions of extremely low temperatures, determining the maximum length of the hose line before icing begins. It is shown in the paper that the maximum length of the hose line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer. At the same time, it is required to combine thermal and hydraulic calculations. The methods are presented in the article for predicting the operability of pumps and hose lines in the conditions of extremely low ambient temperatures, used in fire truck systems for extinguishing fires, including at the energy facilities. It is shown that there are errors and shortcomings in the Methodological Recommendations for ensuring the operability of pump and hose systems of the fire trucks when extinguishing fires in the conditions of extremely low ambient temperatures, including at the energy facilities. It is also shown that the maximum length of the hole line, that is, the distance from the pump to the beginning of icing, should be calculated using the heat balance equation, which is based on two equations of the first law of thermodynamics — for flow and heat transfer.

Adaptive Fault-Tolerant Boundary Control of an Autonomous Aerial Refueling Hose System With Prescribed Constraints

In this article, we propose a redundant fault-tolerant and boundary constraint control in the framework of adaptive method, the neural network approximation, and the barrier Lyapunov function (BLF) with a relaxed initial condition. The actuator failures are compensated by a combination of adaptive methods and redundant actuators when some actuators suffer from partial or even total loss of effectiveness. The radial basis function’s neural network structure is introduced to strengthen the adaptivity in various orientations of the hose and other additionally unmodeled dynamics. To maintain the boundary deflection within a predefined open set after a constraint time, a novel asymmetrical and time-varying BLF is constructed by applying a shifting function to transform the original state into a new state with zero value initially. The performance of the developed adaptive control is demonstrated by numerical simulations. Note to Practitioners—This article is motivated by the limited performances in the existing control designs for flexible unmanned aerial refueling hose systems with failed actuators and boundary constraints. This article considers a redundant actuator case to solve time-varying and partially and totally failed actuator failures that are not settled by adaptive and Nussbaum-based single control. Unlike conventional barrier Lyapunov functions (BLFs), in this article, we resort to a shifting function and propose a novelly asymmetric and time-varying BLF, which is well defined initially and capable to address a deferred constraint control problem. The control design and stability analysis of the actuated system is a Lyapunov-based method rather than relying on semigroup theory or functional analysis, which makes the developed method more engineering orientated. The proposed control strategy is tested to illustrate performances in numerical simulations with the finite difference method.

Performance investigation of fire protection and intervention strategies: Artificial neural network-based assessment framework

This study aims to develop an integrated framework to investigate and assess fire safety strategies, including protection and intervention. The proposed framework is also able to predict potential fire impacts and recommend optimal fire strategies; a case study of British Columbia was considered. The results showed that 58% of the fires were detected by the visual sighting; besides, smoke alarms were not activated for 2% of the fires. Handheld extinguisher, sprinkler system, standpipe and hose systems were able to extinguish 17%, 4%, and 3% of the fires, respectively. Moreover, 30% of the fires were found to have damages beyond the building of origin. Regarding the dollar loss, 26% of the fires caused a very high level of building dollar loss, 20% had a high level of content dollar loss, and 18% of the fires caused a high level of total dollar loss. The investigated variables are found to be statistically significant, with a p-value < 0.05. The proposed ANN model was able to predict fire impacts very strongly, with R2 equal to 85%. Finally, the optimal set of predictors for minimal fire impacts were determined. These results assist decision-makers to enhance and invest in specific fire safety strategies accordingly.

Исследование параметров интенсивности охлаждения компрессионной пены при подаче по насосно-рукавным системам в условиях низких температур

Introduction. The article describes a methodology and a program of experimental studies to determine the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at low temperatures. The numerical values of the parameters of the cooling strength of the compression foam when feeding through the fire hose 20 m long are determined. The experimental dependences of the parameters of the cooling strength of the compression foam on the multiplicity and mass flow are obtained. Goals and objectives. A program and methodology for experimental studies to determine the parameters of the intensity of cooling of compression foam when feeding through pumping and hose systems has been developed. To carry out experimental studies, the following tasks were set: - development of a measuring complex for determining the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at negative temperatures; - determination of the physical model of the movement of the compression foam when feeding through the fire hoses; - development of a program and methodology for experimental research to determine the mass flow rate of compression foam. Methods. Methods of mathematical analysis of statistical data obtained during experimental data were used to determine the parameters of the cooling strength of compression foam when feeding through the pumping and hose systems. Results and its discussion. The numerical value of the cooling of the compression foam when feeding through the pumping-hose systems at low temperatures was obtained experimentally, depending on the multiplicity along the length of the hose line. Conclusions. 1. A program and methodology for conducting experimental studies to determine the parameters of the cooling strength of compression foam when feeding through pumping and hose systems at low temperatures has been developed. 2. As a result of the experimental studies, data were obtained on the rates and parameters of the cooling strength of the compression foam when feeding through fire hoses in winter at various negative temperatures. To measure the parameters of the cooling strength of compression foam when feeding through fire hoses at negative ambient temperatures, a measuring complex was developed and assembled. 3. The data obtained will make it possible to evaluate the parameters of the compression strength of foam cooling when feeding through the pumping and hose systems at low temperatures. Keywords: intensity of cooling, compression foam, foam-air mixture, pumping-hose system, foam generating unit, a unit for generating and supplying compression foam, low temperatures

Vibration Control for Spatial Aerial Refueling Hoses With Bounded Actuators

This article presents a control scheme for stabilizing a vibrating flexible hose used for aerial refueling subject to bounded actuators for the rate and magnitude. A dynamical model of hose systems is captured by partial differential equations (PDEs). Based on the PDE model, a novel boundary control law is proposed to dampen the flexible hose's vibration. The backstepping approach is utilized to devise the control scheme, with the bounded input magnitude and derivative handled by adopting the smooth hyperbolic tangent function. The Lyapunov criterion is exploited to demonstrate the stability of the controlled system. Finally, simulation results are used to evaluate the validity of the derived scheme.

Study of concept for hydraulic hose dynamics investigations to enable understanding of the hose fluid–structure interaction behavior

Fatigue failure of a hydraulic hose systems, caused by violent vibrations, has become a critical factor creating operational and maintenance cost for the end user of rock drill equipment. Similar behavior is also appearing in, for example, forestry machines. Hoses are used as parts of the energy feeding system in machines such as the ones use for mining and civil construction operations. This work aims to create an understanding of the dynamic behavior of a selected hydraulic hose. The numerical modeling approach selected includes a boundary element method approach in the fluid-elastic analysis of the dynamics of a pressurized hose with conveying fluid. Experimental modal analysis was used to validate the numerical model. Pre-tension and pressure-induced tension were monitored with an in-house-developed strain gauge–based load cell. The analysis and experiments show that a complex coupling, of pure structural bending modes, appears when the hose is subjected to internal flow. Some of the modeshapes show a circular motion of the hose cross sections. As shown in this article, these coupled modes become increasingly sensitive to external or internal excitation with increasing flow rate. To illustrate the strength of the proposed approach, the second part of the work in this article presents a parametric study of hose dynamics for hoses with typical dimensions used in industrial applications. This investigation of how different parameters influence the dynamic characteristics of hydraulic hoses shows, for example, that hose end-support stiffness has a large impact on the stability and dynamic behavior of the hose. A soft support tends to create a static instability–type behavior where the lowest frequency mode frequency decreases to levels close to zero with increasing flow speed. Pre-tension of the hose has a stabilizing effect on the hose dynamics. In the case when the internal pressure of the hydraulic hose does not generate tension of the hose, then the increase or decrease in the internal pressure has limited influence on the hose dynamics: this is at least a conclusion valid in the investigated 100–210 bar pressure range. In addition, a smaller diameter hose is more sensitive than a larger diameter hose, and this is valid as long as the pre-tension is high enough to maintain static stability in the entire flow rate range.

Analysis of the possibilities of using stainless steel flexible hose systems in gas installations in Poland

Analysis of the possibilities of using stainless steel flexible hose systems in gas installations in Poland

Active Vibration Suppression of Uncertain Hose and Drogue Systems in the Presence of Actuator Nonlinearities

This paper investigates vibration suppression of uncertain hose and drogue systems in the presence of actuator nonlinearities. Firstly, a previously presented model of the hose and drogue systems is extended to describe how the hose and drogue systems restrain the vibration, while the accompanying unknown aerodynamic coefficients are estimated by invoking the parameter projection method. Subsequently, for the actuator nonlinearities of dead-zone and saturation, a smooth dead-zone approximate function is constructed to design the dead-zone compensation method, based upon which the proposed control scheme can handle actuator dead-zone and saturation simultaneously while improving the output efficiency of the actuator. Next, for the actuator nonlinearities of backlash and saturation, a smooth backlash inverse is constructed based upon which the presented control scheme can cope with the both actuator nonlinearities simultaneously. Finally, by utilizing backstepping method and hyperbolic tangent function, the proposed control schemes can also achieve the control objectives of vibration suppression and external disturbance attenuation. Simulation examples are included to demonstrate the validity of the proposed control schemes.

Efecto del riego por goteo y exudación sobre el rendimiento de hortalizas en clima frío

Los pequeños productores en el sur de Colombia, dependen de la precipitación pluvial para el riego de sus cultivos; sin embargo, los periodos de sequía han aumentado, amenazando el rendimiento de las cosechas, por lo tanto, se ha incremento el uso del riego presurizado. El objetivo fue comparar el efecto de los sistemas de riego por goteo y exudación en diferentes ciclos de cultivos sobre el rendimiento de lechuga (Lactuca sativa L.), repollo (Brassica oleracea L. var. Capitata) y brócoli (Brassica oleracea L. var. Italica). Se utilizó un diseño de Bloques Completos al Azar con arreglo bifactorial. El factor uno corresponde a un sistema de riego (riego por goteo, cinta exudante y sin riego), mientras que el factor dos fue representado por dos ciclos de cultivo (primero, entre septiembre 9 y diciembre 12 de 2013 y segundo, entre marzo 11 y junio 13 de 2014). Con el sistema de riego por goteo, el rendimiento fue mayor para todas las hortalizas. Para lechuga se obtuvieron 20t/ha y presento una disminución de 13% y 18% para el tratamiento testigo y riego por exudación, respectivamente. En repollo el rendimiento fue de 53t/ha y presentó disminución del 35% en los tratamientos testigo y riego por exudación. En brócoli se obtuvieron 13t/ha, donde el tratamiento testigo se redujo en un 59%, mientras que en el sistema de riego por exudación fue de 40%. Con relación al análisis económico la falta de riego presento relación beneficio costo menor en todos los experimentos.

Transduction as energy conversion: Harvesting of acoustic energy in hydraulic systems

Energy harvesting from acoustic energy sources is a form of transduction. While energy densities in typical airborne acoustic noise fields are extremely low, those in hydraulic systems may be orders of magnitude greater and represent an opportunity for direct energy conversion from piezoelectric materials for powering sensor and communication nodes. Hydraulic systems are challenging from a design perspective in that the device must be capable of withstanding static pressures up to and exceeding 35 MPa, while being simultaneously exposed to dynamic pressures on the order of 3.5 MPa. Hydraulic pressure energy harvester devices have been developed to exploit the high energy densities of dynamic pressures in hydraulic systems. There is an immediate application for this technology in that state-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring for early detection of incipient failures. This paper presents the acoustic and electromechanical modeling of the piezoelectric power output from dynamic pressure in terms of the force transmitted into an energy harvester designed for hydraulic systems.

Ageing of thermoplastic umbilical hose materials used in a marine environment I – Polyethylene

This study of the behaviour of high-density polyethylene umbilical hoses subjected to constant and cyclic variation of pressure and temperatures attempts to simulate the temperatures and stresses experienced in offshore operations. The hoses are used to carry fluids to the top of the wellhead and provide protection for the electrical and optical controls systems. Measurements are reported for exposures at 40℃, 70℃ and 100℃ in water, methanol and xylene, using an applied pressure of 200 bar. The changes in the physical properties of the hose were monitored by measurement of the tensile properties, dynamic mechanical thermal analysis, differential scanning calorimetry and gravimetric uptake of the fluids. Significant changes occur immediately on application of pressure and reflect changes in crystallinity. The rates and extent of the modifications depend primarily on the ageing temperature but are also influenced by the fluid. Water has little effect on the rate at which ageing occurs, whereas xylene, which is a potential solvent for high-density polyethylene, exhibits characteristics of plasticization. Methanol behaves as a weak solvent and shows characteristics intermediate between xylene and water. Burst tests carried out on the aged material show that significant loss in strength is only observed with the highest temperatures and most aggressive solvent systems. The study indicates that engineers should use pressure-aged rather than initial materials data when designing umbilical hose systems.

Energy harvesting from hydraulic pressure fluctuations

State-of-the-art hydraulic hose and piping systems employ integral sensor nodes for structural health monitoring to avoid catastrophic failures. Energy harvesting in hydraulic systems could enable self-powered wireless sensor nodes for applications such as energy-autonomous structural health monitoring and prognosis. Hydraulic systems inherently have a high energy intensity associated with the mean pressure and flow. Accompanying the mean pressure is the dynamic pressure ripple, which is caused by the action of pumps and actuators. Pressure ripple is a deterministic source with a periodic time-domain behavior conducive to energy harvesting. An energy harvester prototype was designed for generating low-power electricity from pressure ripples. The prototype employed an axially-poled off-the-shelf piezoelectric stack. A housing isolated the stack from the hydraulic fluid while maintaining a mechanical coupling allowing for dynamic-pressure-induced deflection of the stack. The prototype exhibited an off-resonance energy harvesting problem since the fundamental resonance of the piezoelectric stack was much higher than the frequency content of the pressure ripple. The prototype was designed to provide a suitable power output for powering sensors with a maximum output of 1.2 mW. This work also presents electromechanical model simulations and experimental characterization of the piezoelectric power output from the pressure ripple in terms of the force transmitted into the harvester.

Water Supply Performance and Fire Suppression during the World Trade Center Disaster

This paper describes the New York City water supply performance and suppression of fire during the World Trade Center (WTC) disaster. The water losses sustained by damaged water distribution pipelines are discussed and their impacts on emergency response and telecommunications and transportation infrastructure are noted. The results of hydraulic network analyses are presented to quantify the performance of hose and engine relay systems from fireboats to the WTC site. The results of an analytical study of firefighting relay systems are summarized to provide guidance on the most effective selection of hose size, number of hose lines, and engines for future use of fireboats for landside fire protection. The fire department response to the WTC disaster is compared with similar response to the 1989 Loma Prieta earthquake. Drawing on lessons from both events, recommendations are made for improved emergency planning and services.

Anästhesiologische Aspekte bei der Versorgung von Kindern in „nicht spezialisierten Abteilungen”

Paediatric perioperative care represents specific challenges related to the distinct developmental, anatomic and physiological characteristics of children, requiring specialised expertise, including pharmacology. A specially trained anaesthesia team, an appropriate environment and appropriate paediatric-sized equipment (endotracheal tubes, cannulas) represent key factors in determining the perioperative outcome for this population. Other important equipment that must be adapted to the paediatric population include: Non-invasive anaesthesia monitoring equipment (ECG, blood pressure cuff, pulse oximetry, capnography, oxygen monitor, volatile gas concentration monitor, peripheral nerve stimulator and temperature probe); as well as specialised ventilators that allow pressure- and volume-controlled ventilation with volumes as low as 20 ml, variable high frequency ventilation up to 60 breaths per minute and paediatric ventilator hose systems with automatic correction for compliance. Perioperative pain management is important in the paediatric population, with regional anaesthesia techniques (usually done under general anaesthesia) being increasingly accepted in all age groups. These techniques, however, should be performed by experienced anaesthesologists and surgeons only. If these conditions are not met, surgical procedures should not be performed except in the case of an emergency when transportation to a specialised paediatric facility cannot be done safely. This is particularly critical for premature babies, newborns, and infants up to 3 years of age.

Energy requirements for transport and surface application of liquid pig manure in Manitoba, Canada

The objective of this study was to conduct a thorough accounting of energy used to transport liquid pig manure from farm storage to the field and to surface-apply the manure. Energy consumption was determined using both energy data from the literature plus data from field-scale research. Energy consumption was compared between two manure application systems (the drag hose and the slurry wagon systems) and two application timing treatments (single vs. twice-annual manure application). The single annual application of liquid pig manure applied at 81.5 m 3 ha −1 and transported 1.8 km from storage to field consumed 2180 MJ ha −1 with the drag hose system and 2185 MJ ha −1 with the slurry wagon system. The twice-annual manure application regime used 2726 and 2209 MJ ha −1 for the drag hose and slurry wagon systems, respectively. When energy use was calculated on the basis of MJ per kg of available N, liquid pig manure applied once annually with the slurry wagon system provided N at 17.76 MJ kg −1 of available N, which was 33% of the energy cost of N from anhydrous ammonia and 23% of the energy cost of N from urea. Manure transport distance could be increased to 8.4 km before the energy cost per kg of available N from pig manure was equivalent to anhydrous ammonia, and up to 12.3 km before the energy cost of manure N was equivalent to urea N. Despite the high energy cost to deliver liquid pig manure from storage to field, the much lower cost per kg of available N compared to inorganic fertilizer N highlights the opportunities that exist for improving the energy efficiency of industrial agriculture by replacing inorganic fertilizers with manure.

Canister for Releasing Marked Fish at Depth in Hydroelectric Dam Gatewells and Forebays

At Pacific Northwest hydroelectric dams, surface containers or hose systems have been used to release marked juvenile Pacific salmon Oncorhynchus spp. for fish passage studies. Because these release methods introduce marked fish to unknown depths and hydraulic conditions, they may compromise study results. We constructed a canister and frames for releasing marked fish at predetermined depths and locations in the gatewells and forebays of hydroelectric dams. The canister performed as anticipated, avoiding injury to fish and allowing them to acclimate to depth prior to release. Acclimation is accomplished by slowly lowering the canister to the desired depth and holding the canister for a period of time before release. A total of 1,000 yearling and subyearling chinook salmon O. tshawytscha were released with this canister over a 2-year period in studies of guidance and orifice passage systems. About 98% of these fish were recaptured, with no injury or descaling attributed to the release canister. This release method allows time for acclimation as well as repeatable positioning of the canister for release of fish at depth for studies at hydroelectric dams on the Columbia and Snake rivers.

Klimatisierung von Narkosegasen bei Einsatz unterschiedlicher Patientenschlauchsysteme

During general anaesthesia gas climate significantly is improved by performance of low flow techniques. Gas climatisation, however, markedly also will be influenced by the temperature loss at, and corresponding water condensation within the hoses, factors which are related to the technical design and material of the patient hose system. The objective of this prospective study was to investigate 1. how anaesthetic gas climatisation during minimal flow anaesthesia is influenced by the technical design of different breathing hose systems in clinical practice. 2. to investigate, whether a sufficient gas climatisation also can be gained with higher fresh gas flows if that hose system is used, proven beforehand to optimally warming and humidifying the anaesthetic gases. Three different systems, a conventional two-limb hosing consisting of smooth silicone hoses, a coaxial hosing, and a hosing consisting of actively heated breathing hoses, attached to a Dräger Cicero EM anaesthesia machine, were used during minimal flow anaesthesia with a fresh gas flow of 0.5 l/min. Gas temperature and absolute humidity were measured at the tapered connection between the inspiratory limb and the breathing system as well as at its connection to the endotracheal tube. The best gas climatisation was observed if heated breathing hoses were used. Thus, using this hosing, additionally gas temperature and humidity in the inspiratory limb were taken at fresh gas flow rates of 1.0, 2.0 and 4.4 l/min respectively. Measurements were performed in all groups at all general anaesthesias lasting at least 45 minutes during the lists of eight different days each. In minimal flow anaesthesia, with all hose systems likewise, generally an absolute humidity between 17 to 30 mgH2O/l is reached at the endotracheal tube's connector during the course of the list. Only in the first cases of the day there was a short delay of 15 to 30 minutes before reaching a humidity of at least 17 mgH2O/l. Only with heated hoses, however, humidity frequently even exceeded 30 mgH2O/l. If conventional or coaxial hosings were used, during minimal flow anaesthesia gas temperatures in an acceptable range between 23 to 30 degrees C were measured at the tube connector. With heated hoses, however, warming of the gases was excellent with gas temperatures between 28 to 32 degrees C. In minimal flow anaesthesia climatisation of the anaesthetic gases proved to be best if heated hoses were used. Thus, using heated hose systems another three trials with increasing fresh gas flow rates of 1.0, 2.0 and 4.4 l/min respectively were performed. Whereas climatisation of the anaesthetic gases still was found to be optimal with a fresh gas flow of 1.0 l/min, the humidity dropped drastically to values lower than 17 mgH2O/l at 2.0 l/min and even down to 10 mgH2O/l at a flow rate of 4.4 l/min. Gas temperatures, however, turned out to be independent of the flow and remained at 28-32 degrees C, even at a flow as high as 4.4 l/min. Using conventional hose systems and coaxial hosings acceptable, but not optimal climatisation of the anaesthetic gases can be gained if minimal flow anaesthesia is performed. The use of a coaxial hose system seems to lead to improved climatisation in long lasting procedures only. In routine clinical practice, however, conventional and coaxial hose systems are similar in respect to the climatisation of breathing gases. Heated breathing hoses performed markedly better in terms of climatisation of the breathing gas than the coaxial and the conventional hose system. With this hosing not only sufficient but optimal moisture and temperature values are realized. Optimal climatisation, however, only can be gained if low flow anesthetic techniques with fresh gas flows equal or less than 1 l/min are performed. With higher fresh gas flow rates the humidity decreases markedly while high gas temperatures are maintained. (ABSTRACT TRUNCATED)

Use of Pipelines to Improve Surface Irrigation in Hebei Province, China

This paper describes the use of buried-pipe systems and flexible surface hoses in Hebei Province, China and their contribution to improved water use and increased management flexibility. Buried-pipe and hose systems facilitate the mixing and delivery of saline shallow ground water with fresh surface water or deep ground water. The average area served by a buried-pipe system is 4–5 ha. A substantial increase in irrigation command areas has resulted from the adaptation of existing buried-pipe systems to incorporate the use of surface hoses to distribute irrigation supplies from the outlet. New developments use a flexible hose directly connected to a tubewell pump or to larger buried-pipe systems, in many cases facilitating the conjunctive use of water from several sources. The distinctive features of system design, construction, and operation are described, along with capital cost estimates and an outline of benefits, which include flexibility to grow small areas of high-value crops.