Cold Water Research Articles

Facile dip-coating of silk fibroin/tannic acid@CaCO3 hybrid film with superhydrophilicity on the surface of polypropylene nonwovens for oil–water separation

Superhydrophilic membrane materials are widely used for oil/water separation due to their excellent resistance to anti-fouling underwater. The key factors for realizing superhydrophilicity of membranes are the introduction of hydrophilic groups and the construction of surface micro/nano roughness structures. Herein, we propose a simple, mild, and green dip-coating method to prepare silk fibroin (SF)-tannic acid (TA)@CaCO3 hybrid film to achieve superhydrophilicity of polypropylene nonwovens (PP). Specifically, the hydrophobic interactions between SF and hydrophobic materials were used to create the pre-coatings. TA molecules were deposited onto the surface of SF via hydrogen bonding to provide phenolic hydroxyl groups for achieving the hydrophilicity of PP membranes. Then, the CaCO3 was synthesized in situ by introducing Ca2+ into the pre-coating while depositing TA to construct micro/nano-roughness structures on the PP membrane surface for obtaining superhydrophilicity. PP-SF-TA@CaCO3 membranes exhibit outstanding superhydrophilicity and underwater superoleophobicity, with separation efficiencies exceeding 99 % for a variety of oil–water mixtures and oil-in-water emulsions, and water fluxes ranging from 4000 L m-2h−1 to 5500 L m-2h−1. The separation efficiencies remained above 99 % throughout 50 separation cycles, indicating the excellent separation stability of the modified membranes. Moreover, no significant loss of separation efficiency was observed when separating oil mixtures from harsh water sources, including acidic, alkaline, cold, and hot water. Therefore, the membranes modified by the above process have a promising application in the practical separation of oily wastewater.

Spring circulation characteristics and formation mechanism in the Beibu Gulf

Spring circulation in the Beibu Gulf remains an underinvestigated research topic. Model results validated by observations reveal that the northern and southern parts of the Beibu Gulf are controlled by an enclosed cyclonic gyre and a cyclonic gyre, respectively, while in the vertical, the circulation at the surface differs from those in the middle and deep layers. Contrary to that of the classical view, the modeled Qiongzhou Strait (QS) current flows eastward during some days in spring. This eastward current has an occurrence proportion of 29.3–55.4%, and its longest duration period is 7~18 d. The average current in the QS in spring is approximately westward except in some typical years. In spring, the northern Beibu Gulf is affected by the cold water mass (CWM), which is depicted by the 12°C and 10°C isolines in strong and weak years, respectively. Sensitivity experiments show that the heat flux is dominant in the northern Beibu Gulf via the effect of the CWM, and the monsoon wind favors the formation of the cyclonic gyre. Conversely, the cyclonic gyre in the southern Beibu Gulf is jointly driven by the monsoon wind and heat flux, with the effect of the monsoon wind being more significant. The current off the northern coast of Vietnam (VNC) can be either northeastward or southwestward in spring in different years. The VNC is mainly controlled by the elevation gradient along the northern coast of Vietnam, and the Coriolis force, horizontal advection, and vertical diffusion also play significant roles. Additionally, the CWM is mainly controlled by the heat flux whereas the monsoon wind plays a secondary role. And the VNC, current in the QS, CWM, and cyclonic gyre jointly affect nutrient distributions in the northern Beibu Gulf.

COMPARISON OF THE EFFECTIVENESS OF INTERMITTENT PNEUMATIC COMPRESSION, COLD WATER IMMERSION, AND A PASSIVE PROTOCOL IN THE RECOVERY OF MUSCLE DAMAGE INDUCED BY PLYOMETRIC EXERCISE

Introduction: Muscle fatigue is recognized as one of the causes of injury in sports. Recovery methods are frequently used by sports teams. However, research into the effectiveness of such methods remains limited. Methods: Eleven recreational athletes participated. The study lasted four weeks; the first was dedicated to familiarization, and the last three weeks were to follow-up. Volunteers performed bout of 100 drop jumps, followed by intermittent pneumatic compression (IPC), cold water immersion (CWI), or passive recovery; each method performed in a different week. Variables included were triple horizontal jump (THJ), serum creatine kinase (CK), and muscle soreness; and were registered before, 24, 48, and 72 hours after exercise. Results: Although muscle soreness normalized after 48 hours with the IPC (p = 0.18), it remained altered after 72 hours with the CWI and passive recovery (p = 0.01 and p = 0.01, respectively). With regards to the CK, normalization was observed within 48 hours of CWI (p = 0.31), while the IPC and passive resulted in normalization after 72 hours (p = 0.14 and p = 0.22, respectively). In relation to the THJ, normalization was observed within 48 hours of CWI (p = 0.25), 72 hours after the passive method (p = 0.21), and showed late reduction with IPC, after 72 hours (p = 0.01). Conclusion: objective variables demonstrated better results with the use of CWI.

Freshwater discharge drives latitudinal changes of phytoplankton composition on the continental shelf off Chilean Patagonia

A high-resolution survey of distribution, abundance and composition of phytoplankton was carried out for the first time in surface waters of the continental shelf off Chilean Patagonia (41–48°S). An Imaging FlowCytobot was used along the survey track to record phytoplankton in the size range of 10–120 μm during the austral spring of 2018. Phytoplankton community structure was complemented with continuous underway measurements of temperature and salinity, and physicochemical parameters of the water column at 35 oceanographic stations. Our results evidenced two main macrozones with distinctive phytoplankton assemblages delimited latitudinally at ~45°S. The northern macrozone was characterized by higher surface temperature and salinity, Si:N ratio > 1, diatoms of the genera Thalassiosira and Chaetoceros, and dinoflagellates accounting for over 70% of the total abundance. The southern macrozone, with lower surface temperature and salinity and Si:N ratio < 1, was characterized by members of the genera Guinardia, Lauderia and Cerataulina, representing over 60% of the total phytoplankton. These changes were attributable to the strong influence of freshwater at latitudes higher than 45°S and the enhanced discharge of meltwaters from Patagonian icefields in the area of the Taitao Peninsula and the Gulf of Penas (47–-48°S). Fresh and cold waters impacted the water column stratification and the availability of dissolved silicic acid with potential effects on phytoplankton composition and diatom cell silicification and, thus, on carbon exportation. Our estimations of phytoplankton carbon were comparable to those observed in Patagonian fjords and the highly productive upwelling ecosystem of central Chile. We suggest that the continental shelf off Patagonia can contribute significantly to strengthen the biological carbon pump through the synthesis, exportation, and sequestration of phytoplankton-based organic carbon in the southeastern Pacific Ocean.

USE OF A TWO-STAGE COMBINED SCHEME FOR HEAT EXCHANGERS CONNECTION IN HEATING POINTS FOR HOT WATER SUPPLY OF INSULATED BUILDINGS

The article addresses the features of the functioning of centralised heat supply systems of residential micro-districts considering the improvement of thermal insulation of existing buildings. It also analyses the performance characteristics of hot water supply heaters installed on individual heat points of insulated buildings. The authors compared the heat transfer surface area of heaters and network water flow rate through the heating point for one-stage and two-stage combined schemes of connection of heat exchangers and heat networks. The analysis of calculation results showed that using a two-stage combined connection scheme reduces the consumption of network water through the individual heat supply unit compared to the one-stage scheme. However, the two-stage scheme causes the necessity to increase the heat transfer surface area compared to the one-stage connection scheme. We generalised the results by formulas for calculating water flow rate from distribution heat networks and heat transfer surface area. It is possible to use the obtained results to develop a strategy for reforming micro-district centralised heating systems. Using a two-stage combined connection scheme for hot water supply heat exchangers installed on individual heating points (IHP) of additionally insulated buildings reduces network water consumption through the individual heating point by 8–16% compared to a one-stage connection scheme. The device of a two-stage combined scheme in comparison with a one-stage scheme causes the increase of heat transfer surface area of heat exchangers of the hot water supply of individual heating points from one and a half to two times depending on the accepted design temperature of heating of cold water at the first stage of the heating unit. The results of calculations are approximated by equations, allowing, with acceptable accuracy, to compare the indicators of two-stage combined and one-stage schemes of connection of water heaters for individual heating points of insulated buildings. Keywords: centralised heat supply, individual heating point, water heaters, hot water supply.

Study on the Genetic Mechanism of Carbonate Rock Type Hot Mineral Water-A Case Study of Diaozhen, Jinan.

Geothermal resources are one of the most valuable resources in renewable energy because of their advantages of green environmental protection, stability, and reliability. Carbonate rock type geothermal reservoirs have great research significance. Carbonate rock type geothermal resources are abundant in the Shandong area. In this paper, we take the carbonate-type geothermal reservoir in the Diaozhen area of Jinan City as the research object, analyze the regional geothermal geological conditions, and identify the geological structure. Through physical logging exploration, hydrochemical analysis, isotope testing, and drilling exploration, we reveal the geothermal genesis mechanism and construct the genetic model of the carbonate geothermal system. The results show that Diaozhen area belongs to a low-temperature geothermal field and weak open karst thermal reservoir and that the reservoir is mainly Ordovician Majiagou group limestone. The thermal insulation caprock is the overlying Quaternary and Neogene strata with a cumulative thickness of 1376 m. The results of geophysical exploration wells and drilling data verify that the Mingshui fracture is seen around 1630-1645m, and the diorite intrusion is seen at 1610m. The Mingshui fracture connects the deep and shallow aquifers and is a geothermal fluid migration channel. The geothermal water in the Diaozhen area is mainly from the recharge of atmospheric precipitation, with a rich ion content and easy enrichment of trace elements. The regional thermal reservoir is mainly recharged by the deep circulation lateral runoff of Ordovician karst water. After long-distance deep circulation migration, groundwater continuously absorbs heat from the surrounding rock and is heated to geothermal raw water in the deep part. Deep geothermal water rises along the water-conducting fracture and mixes with shallow cold water to form shallow, low-temperature geothermal water.

FATIGUE BEHAVIOUR OF COPPER-BRAZED 316L STAINLESS STEEL

The plate heat exchanger (PHE) is a component that provides heat to be transferred from hot water to domestic cold water without mixing them with high efficiency. Over the lifetime of the PHE, cyclic pressure acts on the brazing points and the plates, and this may lead to fatigue failure. The fatigue behaviour of the PHE, designed by using copper-brazed 316L (also known as 1.4404) stainless steel, was investigated by performing fatigue tests to obtain the S-N curve of the analysed brazed joint. The fatigue tests have been performed on the Vibrophore 100 testing machine under the load ratio R = 0.1 for different values of calculated amplitude stress. Based on the obtained experimental results, an appropriate material model of the analysed brazed joint has been created, which was validated with numerical calculation in the framework of a program code Ansys. A validated material model can then be used for the subsequent numerical analysis of PHE.

PRODUCT DIVERSIFICATION FOR SUSTAINABILITY INSPIRED BY TRADITIONAL ROGAN PRINTING OF GUJARAT

The age-old artistic practice of rag painting, which is practiced in Gujarat, Peshawar, and Sindh. It involves using a stylus to expertly apply a thick paste made of vegetable colours and castor or linseed oil onto fabric. The Persian origin of the term "Rogan" means "oil-based," emphasizing the process of heating and forming castor oil in cold water to create a viscous material. This art form was once quite popular among the Muslim Khatris group in Gujarat, and it is historically credited to the Afridis, a community of Syrian descent. After the first impression, the cloth is carefully folded to create a mirrored design. The artists used their palms to apply body-temperature paint. Rogan painting, which is well-known for its rich colours and intricate designs that frequently incorporate floral themes, animals, and regional cultural features, has faced challenges due to low awareness and the rise of low-cost, automated textiles. However, there has been a resurgence in recent years, contributed to increased tourists, support from non-profits and local cooperatives, and the prestige of winning awards and recognition. This paper gave insights into the ideation of incorporating and being inspired by Rogan art motifs into product diversification with contemporary designs through embroidery for garment collections.

Effect of Different Drying Techniques on Quality Attributes of Ready to Reconstitute (RTR) Coffee Mix

Coffee is one of the most ubiquitous and culturally significant beverages worldwide, transcending borders and influencing societies in myriad ways. Ready-to-reconstitute (RTR) coffee, often referred to as instant coffee, occupies a unique and significant niche in the global coffee market. In the present study, A mixture of Arabica to Robusta coffee beans in the ratio of 70:30 was found most suitable for manufacture of ready to reconstitute coffee mix. The concentrated coffee decoction prepared using this mixture is to be blended with concentrated milk (30%TS) in the ratio of 1:5 and dried using vacuum tray dryer, tray dryer and freeze dryer. The coffee mix is vacuum-dried at 30 to 45 degrees Celsius with a vacuum of 600 to 650 mm of Hg, gives better quality of dried product. The optimized final product has better rheological and physico chemical characteristics. In present study found that ready to reconstitute coffee mix has solubility in hot water 26.4 seconds and 2.74 minutes in cold water at 16◦C. The freeze-dried coffee mix powder exhibited reduced flowability 42.08 seconds compare to vacuum try dried and tray-dried coffee mix power that was 47.41 and 46.27 seconds respectively. Same as bulk density of freeze-dried powder (0.64 g/cm3) found lowest compare to vacuum tray dried (0.78 g/cm3) and tray dried (0.82 g/cm3) coffee mix powder.

Efficacy of Extracts of Bishop's Flower &lt;i&gt;Ammi majus&lt;/i&gt; against Black Bean Aphid &lt;i&gt;Aphis fabae&lt;/i&gt; Scopoli

Experiments were performed in the laboratory of the Biological Control Department at the Al-Mussaib Technical College during February-July, 2023 for evaluating the efficacy of crude aqueous and alcoholic extracts of flowers and leaves of Bishop’s flower Ammi majus against the black bean aphid, Aphis fabae Scopoli, results revealed that the hot water extract proved superior to cold water extract and hot water extract of flowers was superior compared to leaf extract with mortality of 29.7% nymphs and adults 19.6% respectively.

Influence of Temperatures on Physicochemical Properties and Structural Features of Tamarind Seed Polysaccharide.

Due to the high content of impurities such as proteins in tamarind seed polysaccharide (TSP), they must be separated and purified before it can be used. TSP can disperse in cold water, but a solution can only be obtained by heating the mixture. Therefore, it is important to understand the dispersion and dissolution process of TSP at different temperatures to expand the application of TSP. In this study, pasting behavior and rheological properties as a function of temperature were characterized in comparison with potato starch (PS), and their relationship with TSP molecular features and microstructure was revealed. Pasting behavior showed that TSP had higher peak viscosity and stronger thermal stability than PS. Rheological properties exhibited that G' and G'' of TSP gradually increased with the increase in temperature, without exhibiting typical starch gelatinization behavior. The crystalline or amorphous structure of TSP and starch was disrupted under different temperature treatment conditions. The SEM results show that TSP particles directly transformed into fragments with the temperature increase, while PS granules first expanded and then broken down into fragments. Therefore, TSP and PS underwent different dispersion mechanisms during the dissolution process: As the temperature gradually increased, TSP possibly underwent a straightforward dispersion and was then dissolved in aqueous solution, while PS granules initially expanded, followed by disintegration and dispersion.

Antarctica is less isolated with increasing depth - evidence from pycnogonids

No other group of animals typifies the uniqueness of Antarctic life more than Pycnogonida (sea spiders), with 20% of all known species found in the Southern Ocean, and 64% of these endemic to the Antarctic. Despite nearly 200 years of research into pycnogonids and other benthic phyla in Antarctica, the parameters which drive the distribution and diversity of benthic fauna are still poorly understood. This study aimed to investigate the diversity and connectivity of pycnogonid communities on either side of the Antarctic Polar Front, with an emphasis on the role of water depth, using an occurrence dataset containing 254 pycnogonid species from 2187 sampling locations. At depths shallower than 1000 m, communities to the north and south of the Antarctic Polar Front were distinct, while below this depth this geographic structure disintegrated. The Polar Front, or the expanse of deep ocean it bisects, seemingly acts as a semipermeable barrier to species exchange between well-sampled shallow communities. The less sampled and less understood deep sea appears to be better connected, with high levels of shared species following the northward flow of Antarctic Bottom Water. The exceptionally high diversity and endemism of Antarctic pycnogonids may reflect an apparent competitive advantage in cold waters which leaves them vulnerable to ongoing ocean warming, with increased competition and predation pressures.

Decadal growth pattern of an indicator species Sebastes koreanus in the Yellow Sea and its response to environmental changes at differing scales

Climate change and human activities are significantly impacting coastal ecosystems and the species that inhabit them. Understanding how individual growth of key species varies and responds to environmental changes is essential for a better understanding of population dynamics and prediction of ecological responses to environmental changes. Here, a 20-year growth history of Sebastes koreanus was reconstructed based on otolith chronology analysis. Then the relationships between environmental factors (local and basin scales) and the growth variability were analyzed using a mixed effect model. The reconstructed growth chronology showed distinct inter-annual variability that alternatively increased and decreased, and a rapid increasing trend was observed during 2011–2014. The growth pattern significantly correlated with summer Chlorophyll-a concentration, indicating bottom-up control in the coastal ecosystem of the Yellow Sea. Significant relationships were also detected between otolith growth and winter bottom temperature and summer Southern Oscillation index, the two significant factors that also represent intensity of the Yellow Sea Cold Water Mass (YSCWM), which is the most important hydrographic feature influencing the Yellow Sea. The study result contributes to better understand fish growth plasticity under environmental changes. This result also reveals the relationship between fish dynamics and the YSCWM intensity in the Yellow Sea. The growth condition of S. koreanus could be used as a biological index for the YSCWM intensity and contribute to better understand the influence of the YSCWM on fish populations.

Subacute Influence of Body Cooling on the Perception of Delayed Onset Muscle Pain

Objective: To investigate the subacute influence of the use of body cooling by immersion in cold water on the perception of Delayed Muscle Pain (DOMS), in the posterior leg muscles, 24, 48 and 72 hours after carrying out a three-course muscle fatigue protocol. series of repetitions until concentric failure of the bilateral plantar flexion and dorsiflexion movement. Methods: 22 untrained participants (age: 20.4±1.7 years; body mass: 65.91±15.38kg; height: 166.86±8.47cm) participated in an effort protocol that consisted of three sets of repetitions until concentric failure of the leg muscles, of plantar flexion and bilateral dorsiflexion movement, with one's own body weight. After one minute, through a draw, one of the legs was designated for immersion, up to the height of the popliteal fold, in a vat of ice water (between 12 and 14º C), during three stages of 5 minutes with a 1 minute break between each stage, totaling 15 minutes of immersion. At the same time, the other leg remained in passive recovery, serving as control. After 24, 48 and 72 hours, the individuals were evaluated regarding the perception of DOMS, in both legs, with an analog pressure algometer (pressure of 6kgf/cm²). The perception of pain was signaled by the participants using the Pain Visual Analogue Scale (VAS). Results and conclusions: No statistically significant differences (p&lt;0.05) were found between body cooling and passive recovery, in both groups, in the assessment of perception of DOMS 24, 48 and 72 hours after the exercise protocol.

The Comparative Effectiveness of Using Cold Water Oral Spray and Cold Saline Oral Spray for Thirst Relief in Patients With Endotracheal Intubation in the Intensive Care Unit

Thirst is a common symptom among patients with endotracheal intubation in the intensive care unit (ICU), with an estimated prevalence of 88%. This study was designed to compare the effectiveness of cold saline spray and cold water spray in alleviating thirst, and to explore the maintenance and sustained effects of both groups in relieving thirst among patients with endotracheal intubation in the ICU. Patients with indwelling tracheal tubes in the medical ICU were recruited from one medical center in northern Taiwan and randomly assigned to either the cold saline (n = 18) or cold water (n = 18) group. The cold saline group received three rounds of cold saline spray at a temperature of 2°C - 8°C. Each round consisted of 10 sprays directed toward each of the four surfaces of the oral cavity followed by a 5-minute wait period. This process was repeated three times, with 30-minute intervals between interventions. The cold water group received the same intervention steps using a cold water spray at 2°C - 8°C. Thirst intensity was measured using a numeric rating scale before and after each of the three interventions in both groups. Demographic and relevant physiological data were collected on the participants by reviewing their medical records. Both of the interventions were found to effectively alleviate thirst intensity, with no significant difference between the two groups in terms of thirst intensity reduction after each intervention detected. Only the cold water spray had a maintenance effect, while the two groups had a continuous sustained effect in alleviating thirst intensity. Both of the interventions effectively alleviated thirst, and the cold water spray had both maintenance and sustained effects in alleviating thirst intensity. Based on the results, the cold water spray method may be considered as the priority treatment for thirst alleviation by healthcare providers in the clinical management of patients with tracheal intubation.

Geochemical and Isotopic Techniques Constraints on the Origin, Evolution, and Residence Time of Low‐enthalpy Geothermal Water in Western Wugongshan, SE China

AbstractGeothermal resources are increasingly gaining attention as a competitive, clean energy source to address the energy crisis and mitigate climate change. The Wugongshan area, situated in the southeast coast geothermal belt of China, is a typical geothermal anomaly and contains abundant medium‐ and low‐temperature geothermal resources. This study employed hydrogeochemical and isotopic techniques to explore the cyclic evolution of geothermal water in the western Wugongshan region, encompassing the recharge origin, water–rock interaction mechanisms, and residence time. The results show that the geothermal water in the western region of Wugongshan is weakly alkaline, with low enthalpy and mineralization levels. The hydrochemistry of geothermal waters is dominated by Na‐HCO3 and Na‐SO4, while the hydrochemistry types of cold springs are all Na‐HCO3. The hydrochemistry types of surface waters and rain waters are Na‐HCO3 or Ca‐HCO3. The δD and δ18O values reveal that the geothermal waters are recharged by atmospheric precipitation at an altitude between 550.0 and 1218.6 m. Molar ratios of major solutes and isotopic compositions of 87Sr/86Sr underscore the significant role of silicate weathering, dissolution, and cation exchange in controlling geothermal water chemistry. Additionally, geothermal waters experienced varying degrees of mixing with cold water during their ascent. The δ13C values suggest that the primary sources of carbon in the geothermal waters were biogenic and organic. The δ34S value suggests that the sulfates in geothermal water originate from sulfide minerals in the surrounding rock. Age dating using 3H and 14C isotopes suggests that geothermal waters have a residence time exceeding 1 kaBP and undergo a long‐distance cycling process.

The effect of temperature and sand substrate in tanks on the growth and survival of the warty sea cucumber Neostichopus grammatus

ABSTRACT Water temperature and the presence of sand substrate are considered critical environmental factors affecting the growth of cultured sea cucumbers. This study investigated the effects of water temperatures and the presence or absence of sand substrate in tanks on the growth of N. grammatus fed an equal ration of abalone waste for eight weeks. Sea cucumbers with a mean weight of 8.34 g were used for the study. The treatments used in the study were Ambient water temperature + sand (A + S), Ambient water temperature without sand (A-S), Cold water temperature + sand (C + S), and Cold-water temperature without sand (C–S). The cold/constant water temperature was 16°C and was representative of winter conditions while the ambient/fluctuating water temperature fluctuated between 16.4 and 18.7 °C and was representative of spring conditions. At the end of the study, the sea cucumbers in A + S and C + S treatment groups exhibited an overall weight increase of 21.08% and 6.18%, respectively. The sea cucumbers reared in ambient water temperature exhibited significantly higher mean weight than those reared in cold water (F 1, 66 = 5.69; p = 0.02), and sea cucumbers reared with sand substrate had significantly higher mean weight compared to those without sand substrate (F 1,66 = 19.06; p = <0.001). This study has shown that growth rates of N. grammatus in tanks were higher in ambient temperatures and that stress was reduced in the presence of sand, a habitat that mimics its natural environment. This implies that sand substrate may be necessary for the farming of N. grammatus.

Cold Water Phenomenon in Autumn in the Sea Area of the Xisha Islands

AbstractUsing satellite observation and reanalysis data, we studied the cold water phenomenon in the sea area of the Xisha Islands in autumn from 2003 to 2022. The cold water phenomenon refers to a colder water body relative to its surrounding area, which can partially offset the impact of global warming, thereby contributing to the protection and restoration of marine ecosystems. The cold water with a central position close to the Xisha Islands is distributed in a nearly circular area, and exhibits seasonal and interannual variations. It usually occurs at the end of September, with its intensity rapidly increasing and reaching its peak on October 1, then gradually weakening, and finally disappearing by November 6. The maximum intensity of the cold water phenomenon can reach 1.6°C. This phenomenon notably observed in October 2006, 2009, 2013 and 2022, with intensities reaching 0.9°C, 1.1°C, 1.1°C, and 0.4°C, respectively. The dynamic mechanism of its formation can be described as follows: in autumn of some years, the northeast monsoon occurs in the northern part of the South China Sea (SCS), while the southwest monsoon still prevails in the southern part of the SCS, which causes the generation of strong positive wind stress curl (WSC) near the Xisha sea area. The positive WSC causes cyclonic circulation and further causes upwelling through Ekman pumping, which transports low‐temperature water from the seabed to the sea surface and thus leads to the occurrence of the cold water phenomenon in the Xisha sea area.

Optimization of Nanofluid Concentration for Energy Intensification in Corrugated Plate Type Heat Exchanger

The overall heat transfer coefficient of the heat exchanger will improve with an increase in the flow rate and concentration of nanofluid. But beyond an optimum nanoparticle concentration, the overall effectiveness seems to decrease due to an increase in pressure drop that consequently leads to an increase in pumping power. The novelty of the present work is to find the optimum concentration of CuO-Water nanofluid that exhibits the optimum heat transfer rate and global minimum pumping power, using both experimental and numerical study. The cold nanofluid and hot water entered the counter currently at 303.15 and 333.15 K respectively in the corrugated plate heat exchanger. It was observed from the experimental and numerical results that the values of overall heat transfer coefficient and pressure drop were increased monotonically (454–710 W/(m2-K) and 6–133 Pa respectively), with the increment in the concentration and flow rates of the nanofluid. Because of this trend, it was challenging to figure out the optimum nanofluid concentration using these parameters. Later, a procedure was presented to obtain an optimum concentration of nanofluid, to reduce the hot stream temperature by 288.15 K. The hydraulic power exhibited a global minimum at an optimum concentration of 0.5 vol% of nanofluid.

Molecular beam scattering from flat jets of liquid dodecane and water

AbstractMolecular beam experiments in which gas molecules are scattered from liquids provide detailed, microscopic perspectives on the gas–liquid interface. Extending these methods to volatile liquids while maintaining the ability to measure product energy and angular distributions presents a significant challenge. The incorporation of flat liquid jets into molecular beam scattering experiments in our laboratory has allowed us to demonstrate their utility in uncovering dynamics in this complex chemical environment. Here, we summarize recent work on the evaporation and scattering of Ne, CD4, ND3, and D2O from a dodecane flat liquid jet and present first results on the evaporation and scattering of Ar from a cold salty water jet. In the evaporation experiments, Maxwell–Boltzmann flux distributions with a cosθ angular distribution are observed. Scattering experiments reveal both impulsive scattering (IS) and trapping followed by thermal desorption (TD). Super‐specular scattering is observed for all four species scattered from dodecane and is attributed to anisotropic momentum transfer to the liquid surface. In the IS channel, rotational excitation of the polyatomic scatterers is a significant energy sink, and these species accommodate more readily on the dodecane surface compared to Ne. Our preliminary results on cold salty water jets suggest that Ar atoms undergo some vapor‐phase collisions when evaporating from the liquid surface. Initial scattering experiments characterize the mechanisms of Ar interacting with an aqueous jet, allowing for comparison to dodecane systems.Key Points Molecular beam scattering from flat liquid jets is a powerful technique to elucidate mechanistic detail at the gas–liquid interface. Previous dodecane scattering experiments have uncovered angularly‐resolved thermal desorption fractions and energy transfer at the interface for several small molecule scatterers. Preliminary results on scattering from cold salty water reveal mechanisms of interaction between argon and an aqueous jet.