Warm System Research Articles

Aluminum Leaching from Fluid Warmers: Regulatory Deferral to Clinicians' Decision.

Fluid-warming systems are crucial in surgical and trauma settings because of their key role in preventing or treating hypothermia and enabling proper resuscitation of blood products that are stored cold. Recently, several manufacturers have issued warnings of the possibility of aluminum leaching from their fluid warmers and cautioned about the potential for aluminum toxicity in patients who underwent fluid resuscitation with these devices. Studies suggest that one of the main factors affecting aluminum leaching in this setting is the coating of the aluminum plate itself. Coating, often with a biocompatible material, appears to reduce aluminum leaching by 100- to 200-fold compared with an uncoated plate. Nonetheless, leaching with the coating is still at a level exceeding U.S. regulations. A few aluminum-free warming systems are available on the market, but these are not carried by all providers and some clinicians may be less familiar with their use. Medical device manufacturers will likely design future warming systems with less potential for aluminum blood contact. In the meantime, the risk of inadequate resuscitation, consequent to the proper fluid warmer no longer being available, is contrasted with the risk of potential toxicity. In the situation described here, the regulators deferred the ultimate decision of which fluid warmer to use in a given situation to the risk-benefit decision of the clinician.

An experimental study on the performance of air conditioning system using R-134a And MC-134 refrigerant in D8R caterpillar units

Refrigerant is a crucial cooling component for the refrigeration cycle. In heavy equipment, the cooling system still relies on the R-134a unit with many weaknesses, including global warming effects and other air conditioning system problems. An alternative substitute for R-134a has been found, i.e., a hydrocarbon refrigerant or MC-134. This product has several advantages compared to R-134a, especially its environmentally friendly aspect. It does not contribute to the damage of the ozone layer and is completed with good physical characteristics and thermodynamic properties. Overall, it has better performance than R-134a, proven on the Nissan Evalia unit. This study aimed at testing heavy equipment, especially the D8R caterpillar unit because limited studies discuss heavy equipment regarding its MC-134performance. This research was carried out at the Petrosea Ltd workshop. The research was done through experimental methods. The first stage was retrofitting R-134a with MC-134 on the D8R caterpillar unit. The data collection was conducted ten times with an interval of 3 minutes. The second step WAS using MC-134 and taking the same data as the first step. The compressor work on the MC-134 increased by 145.96% compared to R-134a. The result of the study showed that the heat energy released by the condenser using MC-134 increased by 157.833%. 161.625% for the refrigeration effect, and 5.21% of The COP value, respectively, compared to R-134a.

Using event-related potentials to identify user's moods induced by product color stimuli with different attributes

Color is an important factor affecting users’ moods. Exploring the effect of product colors on users’ moods is key for improving users’ mood experience. Here, Electroencephalogram (EEG) technology was used to study the relationship between users’ moods and product colors. Participants evaluated color images of electric hand drills, and the effect of color system and hue relationship was studied. The mood perception states were obtained based on the participants’ subjective assessment; the results of time–frequency analysis and event-related potentials (ERPs) based on synchronously collected EEG signals were also obtained. Mood data sets related to product color attributes were obtained through analysis of behavioral data and ERPs data. Results of the behavioral experiment showed that the participants were more sensitive to color system than hue relationship. Warm color systems and identity hue relationships elicited more positive moods; the mood’s directions of participants for neutral color systems, similarity and gray color hue relationships were ambiguous, and reaction times were longer. The results of the time–frequency analysis showed that there were obvious ERPs between 100 and 400 ms after stimuli appeared. The results of the ERPs analysis showed that negative stimuli caused significant changes in the amplitude of components N2 and P3, positive stimuli caused it in the amplitude of P3, and neutral stimuli caused it in the amplitude of N400. The results of our study provide accurate quantitative data that can be used to understand the relationship between users’ moods and product colors; these data will aid future product color design research.

Optimal periodic switching strategy for a two‐unit warm standby degradation system

AbstractIn the traditional switching policy of a standby system, the standby unit is switched to the normal operation state only after the active unit fails. In contrast, in satellite engineering, a new periodic switching strategy is used by technicians in the satellite gyroscope standby system. Due to the performance degradation of the gyroscope in the long‐term operation and standby process, satellites may fail on orbit. For this problem, an operation optimization model is established for a two‐unit warm standby degradation system considering the periodic switching strategy. First, the degradation process of the units is described by a multiphase Wiener process. Second, based on the first‐hitting time theory, the analytic expressions of reliability and mean time to failure (MTTF) of the degradation system are derived. Third, the optimal periodic switching interval is determined to maximize the system MTTF by using the particle swarm optimization algorithm (PSO). Finally, a numerical example of a gyroscope warm standby subsystem is provided to validate the proposed model.

Comparative Analysis of Different Designs of Triple Tube Heat Exchangers on the Basis of their Performances

Cooling, warming, and air-conditioning systems, electric utilities, chemical based processing structures, food industry, automotive vehicle radiators, and waste heat recovery units are all examples of heat exchanger implementations. Heat exchangers in power plants include air preliminary heaters, economizers, evaporators, super-heaters, condensing systems, and cooling towers. Theoretical and simulation fluid dynamics assessments of varying patterns of a concentric TTHEX were conducted in this study with the intent of enhancing thermal efficiency.

Environmental Response in Coupled Energy and Water Cloud Impact Parameters Derived from A-Train Satellites, ERA-Interim, and MERRA-2

Abstract Understanding the connections between latent heating from precipitation and cloud radiative effects is essential for accurately parameterizing cross-scale links between cloud microphysics and global energy and water cycles in climate models. Although commonly examined separately, this study adopts two cloud impact parameters (CIPs), the surface radiative cooling efficiency Rc and atmospheric radiative heating efficiency Rh, that explicitly couple cloud radiative effects and precipitation to characterize how efficiently precipitating cloud systems influence the energy budget and water cycle using A-Train observations and two reanalyses. These CIPs exhibit distinct global distributions that suggest cloud energy and water cycle coupling are highly dependent on cloud regime. The dynamic regime ω500 controls the sign of Rh, whereas column water vapor (CWV) appears to be the larger control on the magnitude. The magnitude of Rc is highly coupled to the dynamic regime. Observations show that clouds cool the surface very efficiently per unit rainfall at both low and high sea surface temperature (SST) and CWV, but reanalyses only capture the former. Reanalyses fail to simulate strong Rh and moderate Rc in deep convection environments but produce stronger Rc and Rh than observations in shallow, warm rain systems in marine stratocumulus regions. Although reanalyses generate fairly similar climatologies in the frequency of environmental states, the response of Rc and Rh to SST and CWV results in systematic differences in zonal and meridional gradients of cloud atmospheric heating and surface cooling relative to A-Train observations that may have significant implications for global circulations and cloud feedbacks. Significance Statement Studying climate change requires understanding coupled interactions between clouds, precipitation, and their environment. Here we calculate two parameters to reveal how efficiently clouds can heat the atmosphere or cool the surface per unit rain. The satellite observations and reanalyses show similar global patterns, but there are some differences in areas of deep convection and low cloud regions. Examination of these parameters as a function of their environment shows that reanalyses cool the atmosphere too much per unit rain in environments with low sea surface temperatures and water vapor. Vertical velocity determines whether clouds heat or cool the atmosphere. Both observations and reanalyses suggest that water vapor is the stronger control on how much clouds heat the atmosphere per unit rain.

Operation optimization model for warm standby system based on nonperiodic and imperfect multiple active switching policy

Traditional standby system models predominantly assume that a standby unit is activated only after an active unit fails. However, a periodic active switching policy is adopted for some critical subsystems of on-orbit satellites. For this problem, an operation optimization model for warm standby systems under multiple active switching is studied. First, the multiple active switching processes of the warm standby system are described, and virtual age theory is introduced to analyse the lifetime distributions of the unit in different states. Next, since switching does not always occur perfectly, analytical expressions of the system reliability and mean time-to-failure (MTTF) are derived for the warm standby system under nonperiodic, imperfect multiple active switching, which can be applied to units or systems with arbitrary time-to-failure distributions. Furthermore, by maximizing the MTTF of the warm standby system, the corresponding nonperiodic or periodic switching intervals can be determined by the genetic algorithm (GA). Finally, a numerical example of a gyroscope warm standby system following the Weibull distribution is provided to verify the model applicability, and sensitivity analyses of related parameters are performed to identify useful conclusions.

Optimal sequencing of elements activation in 1-out-of-n warm standby system with storage

Despite the rich body of research on reliability analysis and optimization of warm standby systems, the existing works have mostly failed to consider the practical storage component of such systems. This paper advances the state of the art by modeling and optimizing the reliability of a 1-out-of-n warm standby system with product storage, characterized by a maximum capacity, and specific uploading and downloading paces constraints. The storage may accumulate surplus product when the performance of the operating element exceeds the demand and compensate product deficiency otherwise. A numerical algorithm based on the probabilistic model is first proposed to evaluate the reliability or success probability of the system mission (MSP) that must satisfy a pre-specified demand during a required mission time. As a further contribution, the optimal element activation sequence problem is formulated and solved to maximize the mission success probability. Influences of several model parameters (storage capacity, demand, mission time, element reliability, and storage uploading/downloading pace constraints) on the MSP and optimization solutions are investigated through an example of a power system.

Violation of high-dimensional Bell inequality using narrowband orbital-angular-momentum entanglement from warm atomic vapor

Narrowband biphotons from an atomic ensemble are an extraordinary source for quantum information science. The generation of biphotons in the warm atomic system has many applicable prospects for its simplicity, stability, and compactness. In this article we experimentally demonstrate the generation of biphotons from the spontaneous four-wave mixing (SFWM) process in a warm rubidium vapor cell. By performing high-dimensional Bell-type measurements and mutually unbiased measurements, we maximally obtain a three-dimensional orbital-angular-momentum discrete-variable (DV) entangled state. The violation of high-dimensional Bell inequalities shows the great potential of warm atomic systems in generating DV high-dimensional entanglement. Such narrowband photon pairs may find applications in quantum-memory-based quantum communication networks. Through integration with the continuous-variable (CV) entanglement already existing in the same SFWM platform, our results here pave the way to construct atomic-ensemble-based DV-CV hybrid quantum information protocols.

Retracted: “DEVELOPMENT AND ANALYSIS OF AN INTEGRATED MILD/PARTIAL GASIFICATION COMBINED (IMPGC) CYCLE”

Abstract Around 50% of the world's electrical power supply comes from the Rankine cycle, and the majority of existing Rankine cycle plants are driven by coal. Given how unattractive coal is as an energy resource in spite of its high energy content, it becomes necessary to find a way to utilize coal in a cleaner and more efficient manner. Designed as a potential retrofit option for existing Rankine cycle plants, the Integrated Mild/Partial Gasification Combined (IMPGC) Cycle is an attractive concept in cycle design that can greatly increase the efficiency of coal-based power plants, particularly for retrofitting an old Rankine cycle plant. Compared to the Integrated Gasification Combined Cycle (IGCC), IMPGC uses mild gasification to purposefully leave most of the volatile matters within the feedstock intact (hence, yielding more chemical energy) compared to full gasification and uses partial gasification to leave some of the remaining char un-gasified compared to complete gasification. The larger hydrocarbons left over from the mild gasification process grant the resulting syngas a higher volumetric heating value, leading to a more efficient overall cycle performance. This is made possible due to the invention of a warm gas cleanup process invented by Research Triangle Institute (RTI), called the High Temperature Desulfurization Process (HTDP), which was recently commercialized. The leftover char can then be burned in a conventional boiler to boost the steam output of the bottom cycle, further increasing the efficiency of the plant, capable of achieving a thermal efficiency of 47.9% (LHV). This paper will first analyze the individual concepts used to create the baseline IMPGC model, including the mild and partial gasification processes themselves, the warm gas cleanup system, and the integration of the boiler with the heat recovery steam generator (HRSG). This baseline will then be compared with four other common types of power plants, including subcritical and ultra-supercritical (USC) Rankine cycles, IGCC, and natural gas. The results show that IMPGC consistently outperforms all other forms of coal-based power. IMPGC is more efficient than the standard subcritical Rankine cycle by nine percentage points, more than a USC Rankine cycle by nearly four points, and more than IGCC by seven points.

Smaller fish species in a warm and oxygen-poor Humboldt Current system.

Climate change is expected to result in smaller fish size, but the influence of fishing has made it difficult to substantiate the theorized link between size and ocean warming and deoxygenation. We reconstructed the fish community and oceanographic conditions of the most recent global warm period (last interglacial; 130 to 116 thousand years before present) by using sediments from the northern Humboldt Current system off the coast of Peru, a hotspot of small pelagic fish productivity. In contrast to the present-day anchovy-dominated state, the last interglacial was characterized by considerably smaller (mesopelagic and goby-like) fishes and very low anchovy abundance. These small fish species are more difficult to harvest and are less palatable than anchovies, indicating that our rapidly warming world poses a threat to the global fish supply.

Efficacy and Safety of Forced-Air Warming System versus Passive Warming Measures in Major Surgeries: A Systematic Review

Purpose: To compare the clinical impact of forced-air warming system (Bair HuggerTM, BH) and passive warming measures in major surgery patients. Methods: Databases including Pubmed, Cochrane Library, Clinical Trials.Gov and CNKI were searched to collect studies published before January 2019 that were concerned the clinical effects of Bair Hugger. Two reviewers independently screened the literatures, extracted the data. The revised Jadad scale was used to evaluate the methodological quality of the literatures. Meta-analysis was performed by using Review Manager 5.3.0. Findings: A total of 27 studies were included. The result of meta-analysis showed that BH had a significant advantage in rate of hypothermia (RD = -0.42, 95%CI (-0.68, -0.16)) , shivering (RD = -0.28, 95%CI (-0.43, -0.13)), anesthesia recovery time (MD = -8.27, 95% CI (-13.49, -3.05)), hospital stay (MD = -1.27, 95% CI (-2.05) , -0.48)), while incision infection RD = -0.15, 95%CI (-0.40,0.11)) , intraoperative blood loss (MD = -16.88, 95%CI(-34.73,0.96)), intraoperative blood transfusion (MD = -41.49, 95% CI( -108.36, 25.38)) , pain RD = -0.02, 95%CI(-0.08, 0.03)) and other complications (RD = -0.13, 95%CI(-0.39,0.12)) had an advantage but not significant. Subgroup analyses showed that operation mode and operation duration was the sensitive factors. Conclusion: Compared to passive warming, Bair Hugger has significant advantages in hypothermia protection and further reduces the risk of incision chills and prolonged hospital stay. Combined with the current status of body temperature protection in China, it is necessary to enhance the awareness of body temperature protection, standardize medical behavior, and increase the popularity of active warming systems.

Dissipative electrostatic wave modulation in warm multi-ion dusty plasmas with superthermal electrons

Abstract A theoretical investigation has been carried out to explore the modulational instability (MI) of electrostatic waves in a warm multi-ion dusty plasma system containing positive ions, negative ions and positively or negatively charged dust in presence of superthermal electrons. With the help of the standard perturbation technique, it is found that the dynamics of the modulated wave is governed by a damped nonlinear Schrödinger equation (NLSE). Regions of MI of the electrostatic wave are precisely determined and the analytical solutions predict the formation of dissipative bright and dark solitons as well as dissipative first- and second-order rogue wave solutions. It is found that the striking features (viz., instability criteria, amplitude and width of rogue waves, etc.) are significantly modified by the effects of relevant plasma parameters such as degree of the electron superthermality, dust density, etc. The time dependent numerical simulations of the damped NLSE reveal that modulated electrostatic waves exhibit breather like structures. Moreover, phase plane analysis has been performed to study the dynamical behaviors of NLSE by using the theory of dynamical system. It is remarked that outcome of present study may provide physical insight into understanding the generation of several types of nonlinear structures in dusty plasma environments, where superthermal electrons, positive and negative ions are accountable (e.g. Saturn’s magnetosphere, auroral zone, etc.).

Field measurements and numerical analysis on operating modes of a radiant floor heating aided by a warm air system in a large single-zone church

Space heating can constitute 60–80% of the total energy use of buildings in cold climates. Efficient heating techniques in buildings still rely on operating strategies. In this paper, a church with radiant floor heating in a cold climate is taken as a case of a large single-zone building to analyze the energy use for heating. Field measurements and numerical analysis are both used in the study. Different operating modes of heating, including intermittent heating and constant set-point heating, are compared for energy saving, reliability on indoor climate, and thermal comfort. The intermittent heating by an all-air system with supplied air temperature control results in the highest energy use. The constant set-point air temperature radiant floor heating aided by a warm air system (return air temperature control) is least affected by outdoor temperature with the best reliability and met the thermal comfort requirements throughout the heating season. The main novelty is that an operating mode of cyclic set-point air temperature is proposed. It is found that the small thermal inertia of heating systems should be preferred when the operating mode of cyclic set-point temperature is used to reduce the warm-up period. The results suggest how to operate and reduce the energy use of radiant floor heating systems in a large single-zone building.

Incidental operating room fire from a breathing circuit warmer system: a case report

BackgroundAn airway-associated fire in an operating room can have devastating consequences for patients. Breathing circuit warmers (BCWs) are widely used to provide heated and humidified anesthetic gases and eventually prevent hypothermia during general anesthesia. Herein, we describe a case of a BCW-related airway fire.Case presentationIn this case, an electrical short within a BCW wire caused a fire inside the circuit. Simultaneously, the fire was extinguished, ventilation was stopped, and the endotracheal tube was disconnected from the BCW. The patient was exposed to the fire for less than 10 s, resulting in burns to the trachea and bronchi. Immediately after airway burn, bronchoscopy showed no edema or narrowing except for soot in the trachea and both main bronchus. After the inhalation burn event, prophylactic antibiotics, bronchodilator, mucolytics nebulizer, and corticosteroid nebulizer were started. On bronchoscopy 3 days after the inhalation burn, mucosal erythematous edema was observed and the inflammatory reaction worsened. The inflammatory reaction showed aggravation for up to 2 weeks, and then gradually recovered, and the epithelium and mucous membrane of the upper respiratory tract returned to normal after 4 weeks. Eventually, the patient recovered without long-term complications and was successfully discharged.ConclusionsThis is the first report of a fire caused by BCW. We wanted to share our experience of how we responded to an airway-related fire in an OR and treated the patient. It cannot be overemphasized that the electrical medical appliance associated with the airways are fatal to the patient in the event of a fire, so caution should always be exercised.

Experimental and numerical analysis of air temperature uniformity in occupied zone under stratum ventilation for heating mode

In warm air heating systems, a good indoor air temperature distribution can provide a comfortable indoor environment and reduce energy consumption. Few studies were conducted for the uniformity of air temperature distributions under stratum ventilation (SV) for heating. In this study, the horizontal and vertical air temperature uniformities in an occupied zone were evaluated under SV heating mode. Different indoor thermal environments were created using both experiments and computational fluid dynamics (CFD) simulations. Results showed that the horizontal air temperature uniformity is generally inferior to the vertical direction. Based on the experimental and simulation cases, the maximum horizontal and vertical air temperature gradient is 3.46 °C/m and 2.44 °C/m, respectively. The uniformity of the air temperature distribution can be significantly affected by supply air parameters. The maximum extremum air temperature difference is 6.26 °C at the height of 0.6 m. However, it can be reduced to less than 0.62 °C by varying the supply air velocity, temperature and angle. Appropriate supply air parameters can provide an energy utilization coefficient (EUC) higher than one, showing the potentials of energy saving. A grey relational analysis revealed that the relational degree of the supply air velocity and temperature on the air temperature uniformity is relatively high, followed by the outdoor temperature and then supply vane angle. The results derived from this study can contribute to better understand the characteristics of indoor air temperature distribution under SV heating mode.

Minimum cost replacement and maintenance scheduling in dual-dissimilar-unit standby systems

Recent studies have shown that reusing standby elements during the mission may improve the mission success probability significantly. However, such a benefit cannot be effectively achieved without a careful design of the replacement and maintenance schedule (RMS), which determines work period durations of operating elements and types of maintenance performed for idle elements. This paper makes contributions by modeling and optimizing the RMS for a heterogeneous dual-unit warm standby system with the aim to minimize the total expected mission cost, covering operation, standby and maintenance costs as well as mission failure penalty cost. The two system elements are dissimilar, characterized by different performance, failure time distribution and cost parameters. For a successful mission, a specified amount of work must be accomplished before both elements become failed or unavailable. We propose a new probabilistic model-based methodology for assessing the mission success probability and expected mission cost (EMC) of the considered system. An optimization problem is further formulated and solved to find the optimal RMS minimizing the EMC. A case study of a two-pump oil transfer system is conducted to demonstrate the proposed model and effects of different cost parameters on the optimal RMS solution and corresponding mission success probability and EMC.

Reliability evaluation of demand-based warm standby systems with capacity storage

Warm standby is an energy-saving redundancy technique that consumes less energy than a conventional hot standby method. It can be naturally integrated with an energy storage technique to enhance system reliability. However, the integration approach of both techniques and the advantage it affords to system reliability have not been reported in literature. This study resolves this limitation by formulating a novel reliability model for demand-based warm standby systems with capacity storage. In this model, the chronological characteristics of warm standby components are explicitly explored before and after their activation. Moreover, different utilization sequences of warm standby components and storage components are embedded to analyze the effects of these sequences on system reliability. A multi-valued decision diagram is developed to evaluate system reliability considering successful activation probabilities of warm standby components. This diagram is applicable to arbitrary component lifetime distributions and warm standby systems. Numerical examples are presented to verify the application of the proposed methodology.

Global evidence of aerosol-induced invigoration in marine cumulus clouds

Abstract. Aerosol–cloud–precipitation interactions can lead to a myriad of responses within shallow cumulus clouds, including an invigoration response, whereby aerosol loading results in a higher rain rate, more turbulence, and deepening of the cloud layer. However few global studies have found direct evidence that invigoration occurs. The few satellite-based studies that report evidence for such effects generally focus on only the deepening response. Here, we show evidence of invigoration beyond a deepening response by investigating the effects of aerosol loading on the latent heating and vertical motion profiles of warm rain. Using latent heating and vertical motion profiles derived from CloudSat radar observations, we show precipitating cumulus clouds in unstable, polluted environments exhibit a marked increase in precipitation formation rates and cloud top entrainment rates. However, invigoration is only discernible when the stability of the boundary layer is explicitly accounted for in the analysis. Without this environmental constraint, the mean polluted and pristine cloud responses are indiscernible from each other due to offsetting cloud responses in stable and unstable environments. Invigoration, or suppression depending on the environment, may induce possible feedbacks in both stable and unstable conditions that could subdue or enhance these effects, respectively. The strength of the invigoration response is found to additionally depend on cloud organization defined here by the size of the warm rain system. These results suggest that warm cloud parameterizations must account for not only the possibility of aerosol-induced cloud invigoration, but also the dependence of this invigorated state on the environment and the organization of the rain system.

Improving abiotic stress tolerance in sorghum: focus on the nutrient transporters and marker-assisted breeding.

Identification of molecular markers and characterization of nutrient transporters could help to improve the tolerance under abiotic and low nutrient stresses in sorghum ensuring higher yield to conserve food security Sorghum is an important cereal crop delivering food and energy security in the semi-arid tropics of the world. Adverse climatic conditions induced by global warming and low input agriculture system in developing countries demand for the improvement of sorghum to tolerate various abiotic stresses. In this review, we discuss the application of marker-assisted breeding and nutrient transporter characterization studies targeted towards improving the tolerance of sorghum under drought, salinity, cold, low phosphate and nitrogen stresses. Family members of some nutrient transporters such as nitrate transporter (NRT), phosphate transporter (PHT) and sulphate transporter (SULTR) were identified and characterized for improving the low nutrient stress tolerance in sorghum. Several quantitative trait loci (QTL) were identified for drought, salinity and cold stresses with an intention to enhance the tolerance of sorghum under these stresses. A very few QTL and nutrient transporters have been identified and validated under low nitrogen and phosphorus stresses compared to those under drought, salinity and cold stresses. Marker-assisted breeding and nutrient transporter characterization have not yet been attempted in sorghum under other macro- and micro-nutrient stresses. We hope this review will raise awareness among plant breeders, scientists and biotechnologists about the importance of sorghum and need to conduct the studies on marker-assisted breeding and nutrient transporter under low nutrient stresses to improve the sorghum production.