Changes In Properties Of Water Research Articles

PROBLEM OF ANTIBIOTICS IN NATURAL WATER: A REVIEW

The paper is devoted for influence of antibiotics contamination of natural water on environment, aquatic biosystems and public health and possible solutions of this problem. Untreated or ineffectively treated wastewater is a source of different pathogenic microorganisms and toxic chemicals, including organic and inorganic compounds. A lot of organic contaminants are genotoxic, provoke endocrine disruption and have immune toxicity. In modern world people use a lot of diverse antibiotics for the treatment of various bacterial infections, but antibiotic overuse and insufficient removal by wastewater treatment plants are resulted in accumulation and biotransformation of these compounds in aquatic environment. Antibiotics are pollutants which are very harmful for environment. They cause reduction in microbial biodiversity, including bacterial communities with important ecological functions. It provokes changes in water and soil properties, including pH, nutrients content, soil moisture and many others. Low concentrations of antibiotics cause an occurrence of pathogenic microorganisms which are resistant to antibiotics. It has very negative influence on public health due to increasing of health risk and complication of a medication. Antibiotic type, water and sediment compositions, pH, organic matter, specific surface area and temperature and insolation level have very big influence on distribution and behavior of antibiotics in natural water-sediment systems. Many antibiotics are biodegradable; they are transformed in human organism or by aquatic ecosystem (various plants, algae, bacteria, fungi, etc.). But some antibiotics, including ciprofloxacin, are very stable. These persistent organics are dramatically more harmful for ecosystem stability. In case of ciprofloxacin antibiotics in surface water direct photolysis causes formation of organic compounds, which are more toxic and less photolabile than initial antibiotics. So, the toxicity of pollutants increases synergistically and it cannot be ignored. Nowadays antibiotics removal is very important in drinking water and wastewater treatment due to significant environment and health effects of these pollutants. There are a lot of approaches in antibiotic removal from water, including adsorption, nanofiltration, advanced oxidation processes, etc. All these methods have some advantages and disadvantages. Catalytic photodegradation is one of the most popular methods of antibiotic removal. This process is simple, highly effective and makes possible transformation of antibiotics into components with lower toxicity and environmental impact. Also photocatalysis do not produce a lot of wastes unlike coagulation (sludge) or nanofiltration (concentrate).

Increased presence of Atlantic Water on the shelf south-west of Spitsbergen with implications for the Arctic fjord Hornsund

Atlantic Water is a major contributor to the largest zonal variability in ocean properties and air-sea-ice interaction in the Nordic Seas and the European Arctic. Climate change has amplified warming and intensified extreme events, in both the ocean and the atmosphere, with severe implications for the marine environment. Here, we present our long-term (1999–2020) hydrographic observations from the shelf south-west of Spitsbergen, focusing on the extent of Atlantic and Arctic waters, and we examine their impact on the water masses in Hornsund fjord. Our results show an 8% y−1 increase of the Atlantic Water volume fraction on the shelf during the period 1999–2020, especially noticeable in the last decade. Although this does not imply a significant increase in the amount of waters of the Atlantic origin in the fjord, the greater role of Atlantic Water is attributed to changes in water properties (volume and temperature) of the upper water layer in Hornsund. The strong controlling effect of Arctic Water, transported by the Spitsbergen Polar Current, on the salinity of the fjord surface and intermediate layers is helping to preserve the Arctic character of Hornsund. Nevertheless, ongoing Atlantification of the Nordic and Barents Seas may reduce supply of Arctic Water, thereby diminishing the role of the Spitsbergen Polar Current as the agent mitigating the impact of Atlantic Water on the west Spitsbergen fjords. In the future, this may contribute to the disappearance of the gradation in hydrographic conditions currently observed in the fjords along the west coast of Spitsbergen.

Early Warning of Harmful Algal Bloom Risk Using Satellite Ocean Color and Lagrangian Particle Trajectories

Combining Lagrangian trajectories and satellite observations provides a novel basis for monitoring changes in water properties with high temporal and spatial resolution. In this study, a prediction scheme was developed for synthesizing satellite observations and Lagrangian model data for better interpretation of harmful algal bloom (HAB) risk. The algorithm can not only predict variations in chlorophyll-a concentration but also changes in spectral properties of the water, which are important for discrimination of different algal species from satellite ocean color. The prediction scheme was applied to regions along the coast of England to verify its applicability. It was shown that the Lagrangian methodology can significantly improve the coverage of satellite products, and the unique animations are effective for interpretation of the development of HABs. A comparison between chlorophyll-a predictions and satellite observations further demonstrated the effectiveness of this approach: r2 = 0.81 and a low mean absolute percentage error of 36.9%. Although uncertainties from modeling and the methodology affect the accuracy of predictions, this approach offers a powerful tool for monitoring the marine ecosystem and for supporting the aquaculture industry with improved early warning of potential HABs.

Integration of self-organizing maps, statistical analysis, and hydrogeochemical modeling methods to identify spatio-seasonal variations in mine water quality

Monitoring the quality of mine drainage is an important task in the Ruhr coalfield in western Germany, especially after decommissioning all mining activities in 2018. In this study, seasonal and spatial variations in mine water quality of abandoned coal mines around the lower Ruhr river area were investigated. Statistical analysis, self-organizing maps (SOMs), and hydrogeochemical modeling were used to reveal changes in the water quality of 103 water samples collected between January 2018 and November 2019. An analysis of physical and chemical properties using SOM subdivided mine water samples into five groups: freshwater (groups 1, 2, 3, and 4) and brackish water (group 5) with different physical and chemical characteristics. Freshwater samples were mostly distributed in the southern and central parts, whereas brackish water samples were mostly distributed in the northeastern part of the study area. Approximately 18% of the sampling locations experienced significant seasonal changes during the study period, while 82% of the remaining locations showed only slight variations. Across all groups, seasonal variations in the water quality were less pronounced than differences between southern and northeastern sampling locations. A significant increase was observed in major ion concentrations, TDS, and EC values from southern to northern and northeastern sampling points during the monitoring period. A general trend of approaching saturation state from studied mineral phases was detected with increasing TDS concentrations from groups 1, 2, 3, and 4 to group 5. Trace element concentrations were relatively low, except for several streams with higher Fe and Mn concentrations, and varied between seasons. The SOM approach helped to identify the seasonal changes in mine water properties in the area. The evaluation of changes in mine water quality is useful for the management and protection of water resources, especially drinking water resources, in the densely populated Ruhr area.

Heat capacity, isothermal compressibility, isosteric heat of adsorption and thermal expansion of water confined in C-S-H

Nanoconfinement is known to affect the property of fluids. The changes in some thermo-mechanical properties of water confined in C-S-H are still to be quantified. Here, we perform molecular simulations to obtain the adsorption isotherms in C-S-H as a function of the pore size (spanning interlayer up to large gel pores). Then, fluctuations formula in the grand canonical ensemble are used to compute the isothermal compressibility (and its reciprocal, the bulk modulus), the heat capacity, the coefficient of thermal expansion and thermal pressure, and the isosteric heat of adsorption of confined water as a function of the (nano)pore size. All these properties exhibit a pore size dependence, retrieving the bulk values for basal spacing above 2 nm. To understand why property changes with confinement, we compute structural descriptors including the radial distribution function, apparent density, hydrogen bonds counting, and excess pair entropy of water as a function of the confinement. These descriptors reveal significant structural changes in confined water. The heat capacity shows a good linear correlation with the apparent density, entropy, and hydrogen bond number. The values of water property as a function of the basal spacing are a valuable input for multiscale modeling of cement-based materials.

Heat transfer characteristics of water under supercritical conditions

The paper deals with the problems of describing heat transfer modes in a turbulent flow of supercritical water based on generalization of known experimental data for vertical round tubes. Due to the danger of overheating of heat transfer surfaces, special attention is paid to modes with deteriorated heat transfer. Later, the authors developed a universal model that includes the well-known Dittus–Boelter correlation with corrections for changes in the thermophysical properties of water with temperature and the effect of thermal acceleration occurring in the flow. It is shown that the variation of the coefficients in the correction functions allows us to take into account individual features of changes in characteristics of the process in modes with deteriorated heat transfer. Three forms of displaying the modes of heat transfer to water of supercritical parameters with conditional boundaries of the modes of normal, improved and deteriorated heat transfer are proposed. The estimates of the limiting heat flux obtained in this paper for normal modes are compared with the data of other authors.

Surface hydrographic changes at the western flank of the Sicily Channel associated with the last sapropel

In the eastern Mediterranean Sea, the early Holocene was characterized by major climatic and oceanographic changes that led to the formation of the last sapropel (S1) between 10.8 and 6.1 kyr cal. BP. These hydrographic changes might have altered the water exchange between the eastern and western Mediterranean sub-basins through the Strait of Sicily, but the existing evidences are inconclusive. In the present study we show new evidence from sediment core NDT-6-2016 located at the western flank of the Sicily channel, a key location to monitor the surface/intermediate water exchange between the two Mediterranean sub-basins. We perform paleo-hydrographic reconstructions based on planktic foraminifera ecology for the last 15 kyr cal. BP, including the S1 deposition interval. In addition, δ 18 O measurements in both Globigerina bulloides and Globigerinoides ruber and also major elements analyses in bulk sediment are presented. Our results show that significant changes in surface water properties occurred in W-Sicily characterized by a strong contrast in the seasonal hydrographic conditions during the S1 interval. This study proposes that the oceanographic changes in the eastern Mediterranean associated with the surface freshening promoted by the African monsoon likely triggered a restricted water exchange through the Strait of Sicily. This situation led to limited influence of the surface Atlantic waters into the studied area that favored the development of intense summer stratification and vertical winter mixing. This situation changed at about 7 kyr cal. BP when a decrease in the summer stratification probably reflected the influence of the eastward path of the surface Atlantic Waters. This situation would suggest a reinforcement of the water exchange through the Strait of Sicily that marked the end of the extreme conditions that prevailed in the eastern Mediterranean during the S1 formation. • Surface hydrographic reorganization related to the sapropel S1 is observed for the first time in the central Mediterranean. • The acquired data provide new evidences of a restricted sea surface water exchange during the S1 across the Strait of Sicily. • Paleo-hydrographic reconstructions are based on planktic foraminifera ecology, major element analyses and δ 18 O measurements.

Pengaruh Penyiraman Air Tanah Terhadap Perubahan Sifat Kimia Tanah dan Air Gambut di Kalimantan Tengah

This study observed the changes in chemical properties of peat soil and ground water after irrigation of two peat types: inland and transition peat. The research was carried out in the Basic and Analytic Laboratory of Palangka Raya University. Inland peat and water samples were obtained from Palangka Raya City, meanwhile and transitional peatland was taken from Pulang Pisau Regency, Central Kalimantan Province. Research methods consisted of survey and experimental test with complete randomized design (CRD) consisted of groundwater irrigation treatment and was repeated 3 times. The experimental parameters are soil chemical properties such as Ash Content, Base Saturation (KB), Nitrogen (N), Phosphor (P), Exchangeable Potassium (K-dd), Interchangeable Sodium (Na-dd), Interchangeable Calcium (Ca-dd), Interchangeable Magnesium (Mg-dd), Cation Exchange Capacity (CEC), Aluminum Saturation, Iron (Fe), Sulfate (SO₄), Hydrogen Concentration (pH), and Electrical Delivery Power (EDP), and water chemical properties such as pH, EDP, cation, and anions.. The results showed that there has been an increase in the value of CEC, P, Na-dd, SO₄, pH, and decreased of Ash Content, N, K-dd, Ca-dd, and EDP on transitional peat soils. Meanwhile, the inland peat soils showed an increase of Ash Content, N, P, Mg-dd, a saturation of Al and Fe, and decreased in the value of CEC, Ka-dd, Na-dd, Ca-dd, SO₄, pH, and EDP. There were similar effect of groundwater irrigation, towards soil chemical properties, with an exeption of iron levels (Fe). Iron levels (Fe) in transitional peat increase, but decreased in inland peat.

Numerical investigation of heat transfer characteristics between two particles and supercritical water

This work takes two particles as an example to study the effect of distance and angle between two particles on the average Nusselt number Nu, average heat transfer rate ηb, local Nusselt number Nuφ, and local heat transfer rate ηaφ. It was found that the variation trend of Nu and Nuφ in supercritical water is the same as that in constant property flow, thus indicating that the variation trend of heat transfer between particles and fluid in supercritical water is the same as in constant property flow. The change in physical properties of supercritical water does not have any special effect on the variation trend of heat transfer. The heat transfer is mainly affected by the overlap of temperature field and the overlap of flow field. However, the results of ηb and ηaφ indicate that the variation trend of heat transfer rate is affected by temperature gradient changes and physical property changes.

EFFECTS OF ELECTRICAL CURRENT FREQUENCY ON THE PHYSICOCHEMICAL CHARACTERISTICS OF WASTEWATER

Water plays a crucial role in the growth and development of species on Earth. Changes in the physicochemical properties of water have a large effect on human activities as well. Researchers have studied and evaluated the effects of electrical current frequency (f = 0÷2.000 Hz) on the physicochemical properties (surface tension, dynamic viscosity, specific weight) of wastewater. The effect of electric fields on the physicochemical properties of water, allows it to identify the optimal treatment regimes that promote the intensification of various processes taking place in an aqueous medium or in the presence of water.

Changes in the Subantarctic Mode Water Properties and Spiciness in the Southern Indian Ocean based on Argo Observations

AbstractThe Subantarctic Mode Water (SAMW) plays an essential role in the global heat, freshwater, carbon, and nutrient budgets. In this study, decadal changes in the SAMW properties in the Southern Indian Ocean (SIO) and associated thermodynamic and dynamic processes are investigated during the Argo era. Both temperature and salinity of the SAMW in the SIO show increasing trends during 2004-2018. A two-layer structure of the SAMW trend, with more warm and salty light SAMW but less cool and fresh dense SAMW, is identified. The heaving and spiciness processes are important but have opposite contributions to the temperature and salinity trends of the SAMW. A significant deepening of isopycnals (heaving), peaking atσθ=26.7-26.8 kg m−3in the middle layer of the SAMW, expands the warm and salty light SAMW and compresses the cool and fresh dense SAMW corresponding to the change in subduction rate during 2004-2018. The change in the SAMW subduction rate is dominated by the change in the mixed layer depth, controlled by the changes in wind stress curl and surface buoyancy loss. An increase in the mixed-layer temperature due to weakening northward Ekman transport of cool water leads to a lighter surface density in the SAMW formation region. Consequently, density outcropping lines in the SAMW formation region shift southward and favor the intrusion and entrainment of the cooler and fresher Antarctic surface water from the south, contributing to the cooling/freshening trend of isopycnals (spiciness). Subsequently, the cooler and fresher SAMW spiciness anomalies spread in the SIO via the subtropical gyre.

Local oceanographic conditions link predator-prey dynamics from surface waters to the deep ocean

Offshore pelagic environments are dynamic and rich in biodiversity, yet our understanding of these habitats is lacking as they are surveyed less frequently than coastal areas. We present results from one-year (October 2016i–October 2017) of comprehensive oceanographic mooring measures from a site located 150 nmi offshore Southern California in abyssopelagic waters, spanning water mass, nutrient, primary productivity, fish, and cetacean variables. We identified abrupt changes in water properties, bringing distinct biological communities to our site. Some examples were active acoustically observed backscatter from diel vertical migrators, present during parts of summer and throughout fall, coincided with passive acoustically measured night-time echolocation of common dolphins (Delphinus delphis). Risso’s (Grampus griseus) and Pacific white-sided dolphin (Lagenorhynchus obliquidens) echolocation was also coincident with near-surface backscatter but during winter and early spring. Backscatter during that time was predominantly from small pelagic fishes, as diel vertical migration was virtually absent. Echolocation from Cuvier’s beaked whales was prominent during winter and spring, associated with colder water from the California Current, but were absent in early summer when the water in the deep sea abruptly warmed. This study demonstrates how local oceanographic conditions link predator-prey dynamics from surface waters to the deep sea.

Influence of ocean tides and ice shelves on ocean–ice interactions and dense shelf water formation in the D’Urville Sea, Antarctica

The D’Urville Sea, East Antarctica, is a major source of Dense Shelf Water (DSW), a precursor of Antarctic Bottom Water (AABW). AABW is a key water mass involved in the worldwide ocean circulation and long-term climate variability. The properties of AABW in global climate models suffer from several biases, making climate projections uncertain. These models are potentially omitting or misrepresenting important mechanisms involved in the formation of DSW, such as tides and ocean–ice shelf interactions. Recent studies pointed out that tides and ice shelves significantly influence the coastal seas of Antarctica, where AABW originates from. Yet, the implications of these two processes in the formation and evolution of DSW are poorly understood, in particular in the D’Urville Sea. Using a series of NEMO-LIM numerical simulations, we assess the sensitivity of dense water formation in the D’Urville Sea to the representation of tides and ocean–ice shelf interactions during the years 2010–2015. We show that the ice shelves off Adélie Land are highly sensitive to tidal forcing, with a significant basal melt increase in the presence of tides. Ice shelf basal melt freshens and cools the ocean over significant portions of the coastal seas at the depth of the ice shelf draft. An opposite warming and increase in salinity are found in the upper layers. The influence of ice shelf basal melt on the ocean is largely increased in the presence of tides. However, the production of sea ice is found to be mostly unaffected by these two processes. Water mass transport out of polynyas and ice shelf cavities are then investigated, together with their sensitivity to tides and ocean–ice shelf interactions. Ice shelf basal melt impacts the volume of dense waters in two ways: (1) Dense Shelf Water and Modified Shelf Water are consumed to form water masses of intermediate density inside the ice shelf cavities, and (2) the freshening of the ocean subsurface makes its transformation into dense water by sea ice formation more difficult. These results suggest that ice shelf basal melt variability can explain part of the observed changes of dense water properties, and may also affect the production of dense water in a future climate.

اثر دما بر ضریب نفوذپذیری خاک رسی متراکم و عایق رسی ژئوسینتتیک (GCL)

تاثیر دما در خواص نفوذپذیری خاک‌های رسی متراکم یکی از پارامترهای اساسی در طراحی لایه‌های عایق مهندسی است که در معرض شیرابه‌ها هستند. در این تحقیق اثر دما بر ضریب نفوذپذیری رس متراکم منطقه نازلوی ارومیه و عایق های رسی ژئوسینتتیک و همچنین تاثیر میزان تنش موثر و دانسیته بر نرخ تغییر ضریب نفوذپذیری نمونه های رسی بررسی شده است. دستگاه تعیین ضریب نفوذپذیری سه محوری با دیواره انعطاف پذیر برای اندازه گیری ضریب نفوذپذیری نمونه ها تحت تاثیر دما مورد استفاده قرار گرفته است. با افزایش دما ویسکوزیته محلول کاهش یافته و اثرات دمایی ساختار خاک را تغییر می دهد و تولید حفرات بزرگتر بین ذرات رس می کند و باعث ایجاد تغییر در سطح مقطع موثر جریان شده و آب جذب شده تبدیل به آب آزاد می شود و در نتیجه باعث افزایش ضریب نفذپذیری خاک رسی می شود. افزایش تنش موثر باعث می شود نرخ افزایش در ضریب نفوذپذیری در اثر افزایش دما کاهش یابد. همچنین با افزایش دانسیته خاک رسی، ضریب نفوذپذیری و نرخ افزایش آن کاهش می یابد. بر خلاف خاک‌های رسی، در عایق های رسی ژئوسینتتیک افزایش دما تاثیر چندانی در ضریب نفوذپذیری این لایه ها نداشته و زمانی که این لایه ها در معرض افزایش دما قرار گیرند به عملکرد خوب خود به عنوان یک مانع هیدرولیکی ادامه می‌دهند.

Evaluation of changes in some physico-chemical properties of bottled water exposed to sunlight in Bauchi State, Nigeria

Abstract. It is common for bottled water and other assorted drinks to be seen displayed outside stores and in the sun in most parts of Nigeria. The country is mostly hot year-round, and over the course of the year, temperatures can rise to as high as 40 ∘C around March–April in the study area. The leaching effect of chemicals from polyethylene terephthalate (PET) bottled water was investigated for five commercially available bottled water brands. Temperature, pH, antimony, bisphenol A (BPA), and nitrate levels were measured on days 0, 14, and 28 for control samples and samples exposed to direct sunlight, using destructive sampling technique. Antimony was not detected in brands A, B, and E in the baseline measurement at day 0, while brands C and D had low values; after 28 d all the control samples still had antimony levels within the United States Environmental Protection Agency (US EPA) standard. Meanwhile, all the samples exposed to sunlight exceeded US EPA standard levels at 14 and 28 d, except brand A which was within limit at 14 d with value of 4.59 µg L−1. All control and exposed samples were below the European Union Drinking Water Directive (EU DWD) total daily intake (TDI) of BPA (0.05 mg per kilogram of body weight)−1 d−1. Values obtained for nitrate showed that all control samples did not exceed the US EPA guideline level for nitrates in drinking water for days 0, 14, and 28, while three of the samples, i.e. brands C, D, and E, exceeded the guideline level at day 28. Exposure of bottled water to sunlight was seen to impair the quality of the water for consumption.

Comparative study of the dynamics of laser breakdown in water and hexane using interference microscopy

The changes in the optical properties of water and hexane under femtosecond irradiation (Ti : Al2O3 laser, wavelength 800 nm, intensity ∼1013 W cm−2) are investigated in the cavitation (bubble-formation) regime using interference microscopy in a time interval of ∼1.5 ns since the impact onset. A comparison of the dynamics of radiation-induced processes (solvation of excess electrons, pair recombination, and development of precavitation processes) is performed. The excited-carrier concentration is estimated, and these estimates are found to be inconsistent with the amount of energy that must be transferred to the liquid during a pulse to implement its heating and subsequent cavitation. This inconsistency is especially pronounced for hexane, where ionisation processes can barely be detected by interferometry. The experimental results put new questions about the mechanisms of energy transfer in both polar and nonpolar liquids subjected to intense laser irradiation.

Remote Control of Filchner‐Ronne Ice Shelf Melt Rates by the Antarctic Slope Current

AbstractRecent work on the Filchner‐Ronne Ice Shelf (FRIS) system has shown that a redirection of the coastal current in the southeastern Weddell Sea could lead to a regime change in which an intrusion of warm Modified Circumpolar Deep Water results in large increases in the basal melt rate. Work to date has mostly focused on how increases in the Modified Circumpolar Deep Water crossing the continental shelf break leads directly to heat driven changes in melting in the ice‐shelf cavity. In this study, we introduce a Weddell Sea regional ocean model configuration with static ice shelves. We evaluate a reference simulation against radar observations of melting, and find good agreement between the simulated and observed mean melt rates. We analyze 28 sensitivity experiments that simulate the influence of changes in remote water properties of the Antarctic Slope Current on basal melting in the FRIS. We find that remote changes in salinity quasi‐linearly modulate the mean FRIS net melt rate. Changes in remote temperature quadratically vary the FRIS net melt rate. In both salinity and temperature perturbations, the response is rapid and transient, with a recovery time‐scale of 5–15 years dependent on the size/type of perturbation. We show that the two types of perturbations lead to different changes on the continental shelf, and that ultimately different factors modulate the melt rates in the FRIS cavity. We discuss how these results, are relevant for ocean hindcast simulations, sea level, and melt rate projections of the FRIS.

Probing the structural properties of the water solvation shell around gold nanoparticles: A computational study.

While subjected to radiation, gold nanoparticles (GNPs) have been shown to enhance the production of radicals when added to aqueous solutions. It has been proposed that the arrangement of water solvation layers near the water-gold interface plays a significant role. As such, the structural and electronic properties of the first water solvation layer surrounding GNPs of varying sizes were compared to bulk water using classical molecular dynamics and quantum and semi-empirical methods. Classical molecular dynamics was used to understand the change in macroscopic properties of bulk water in the presence of different sizes of GNP, as well as by including salt ions. The analysis of these macroscopic properties has led to the conclusion that larger GNPs induce the rearrangement of water molecules to form a 2D hydrogen-bond network at the interface. Quantum methods were employed to understand the electronic nature of the interaction between water molecules and GNPs along with the change in the water orientation and the vibrational density of states. The stretching region of vibrational density of states was found to extend into the higher wavenumber region, as the size of the GNP increases. This extension represents the dangling water molecules at the interface, as a result of reorientation of the water molecules in the first solvation shell. This multi-level study suggests that in the presence of GNP of increasing sizes, the first water solvation shell undergoes a rearrangement to maximize the water-water interactions as well as the water-GNP interactions.

Investigation on the correlation between changes in water and texture properties during the processing of surimi from golden pompano (Trachinotus ovatus).

Water and texture properties are important indicators for evaluating surimi and surimi seafood quality. The present study assessed the impact of surimi processing on the water and texture properties and analyzed their correlations. The results showed that the moisture content exhibited significant positive correlations with T22 and A22 (P <0.05). However, water-holding capacity (WHC) revealed significant negative correlation with T21 and A22 (P <0.05). Moreover, correlations between water and texture properties were observed. Moisture content and A22 displayed significant negative correlation with hardness (P <0.05). WHC exhibited significant positive correlations with cohesiveness, springiness, and chewiness (P <0.05), whereas T21 exhibited significant negative correlation with those properties (P <0.05). Springiness is an important indicator for texture properties of surimi gel. T21 and WHC exhibited significant correlations with springiness (P <0.05). We used two equations to assess the relationship between springiness and T21 (y = 9.64 × x2 - 33.79 × x + 29.62, R2 = 0.995, P <0.05) and between springiness and WHC (y = 0.57+ 9.05/{1+e[-29.29 × ( x - 83.90)] }0.01 , R2 = 0.999, P <0.05), respectively. Verification experiments proved that these two regression equations could be used to predict the change law among feature indicators during the processing of surimi seafood. The present study finds an easy-to-control method to monitor the quality of surimi production and processing for all the stages, and provides ideas for quality design of surimi products. PRACTICAL APPLICATION: The quality of surimi seafood is affected by the process used for surimi production. Early detection of the material quality can efficiently prevent resource wastage. The feature indicators and their correlations help in easy-to-control of all surimi processing stages. Low-field nuclear magnetic resonance (LF-NMR) is a fast, nondestructive method for monitoring food real-time, but the instrument is expensive; whereas water-holding capacity and texture profile analysis (TPA) are traditional methods but time-consuming and material-consuming. Surimi enterprises or researchers choose the right methods based on their needs.

Effect of pressure and temperature on solvent transport across nanofiltration and reverse osmosis membranes: An activity-derived transport model

The activity coefficients and equations for transport through nanofiltration (NF) and reverse osmosis (RO) membranes were derived to determine the contribution of the heat of vaporization, molar volume, activation energy (diffusion), thermal expansion, and liquid- and vapor-phase compression. These equations have been derived for pure substances; hence, the measured deviations were obtained from the membrane itself. The inclusion of these effects provides a more accurate prediction of membrane transport than that provided by current models. The model presented herein accurately determined fluxes over temperature and pressure ranges for four different membranes, which the Merten model failed to determine. The transport activity model was applied to water, ethanol, methanol, and n-hexane. The molar volume of water for commercial, brackish-water membranes was approximately equal to that of bulk water, while high-flux brackish-water and NF membranes exhibited significantly lower molar volumes, as compared to that of the bulk water. Surprisingly, slight changes in the molar volumes of water, ethanol, and n-hexane in organic NF membranes were observed. Significant changes in the physicochemical properties of water were identified in the Desal 5 membrane. These results indicate that the molar volume and compressibility enabled the pressure dependence of the RO and NF membranes. For all the membrane types, the resistance to flow, heat of vaporization, and diffusion coefficients controlled the magnitude of changes in flux due to pressure and temperature.