Changes In Water Characteristics Research Articles

Correlation between Water Characteristics and Gel Strength in the Gel Formation of Golden Pompano Surimi Induced by Dense Phase Carbon Dioxide.

The relationship between the gel quality of golden pompano surimi treated with dense phase carbon dioxide (DPCD) and changes in water characteristics was evaluated. Low-field nuclear magnetic resonance (LF-NMR) and nuclear magnetic resonance imaging were used to monitor changes in the water status of surimi gel under different treatment conditions. Whiteness, water-holding capacity and gel strength were used as the quality indicators of the surimi gel. The results showed that DPCD treatment could significantly increase the whiteness of surimi and the strength of the gel, while the water-holding capacity decreased significantly. LF-NMR analysis showed that, as the DPCD treatment intensity increased, the relaxation component T22 shifted to the right, T23 shifted to the left, the proportion of A22 decreased significantly (p < 0.05) and the proportion of A23 increased significantly (p < 0.05). A correlation analysis of water characteristics and gel strength showed that the water-holding capacity of surimi induced by DPCD was strongly positively correlated with gel strength, while A22 and T23 were strongly negatively correlated with gel strength. This study provides helpful insights into the quality control of DPCD in surimi processing and also provides an approach for the quality evaluation and detection of surimi products.

Seasonal variations of natural organic matter (NOM) in surface water supplied to two coal-fired power stations.

Global issues such as pollution and global warming have resulted in changes in water characteristics over the past 20years. Natural organic matter (NOM) which is a major component in water systems has shown an increase globally. This increase in NOM concentration has negatively affected both water treatment processes and drinking water quality. It is subsequently critical to understand the seasonal variations and composition of NOM to be able to address issues related to NOM. In this study, techniques such as ultraviolet-visible spectroscopy, total organic carbon and liquid chromatography-organic carbon detection (LC-OCD) were used for characterisation and quantification of NOM. Two coal-fired power stations were selected for this study with each power station receiving water from a different source, i.e. power station A receives water from the Vaal River and power station B from the Nkomati River. Results from this study demonstrated that composition and concentration of NOM from these two water sources varied seasonally. Characterisation of NOM using the LC-OCD indicated that the different fractions of NOM, i.e. low molecular weight neutrals, low molecular weight acids, building blocks, humic substances and biopolymers, varied seasonally. The dissolved organic carbon concentration and specific ultraviolet absorbance values of the raw water at both power stations showed an increment amid the wet seasons and a decrease amid the dry seasons.

STUDY THE MONTHLY CHANGES IN THE PHYSICAL AND CHEMICAL PROPERTIES OF AL-GARRAF RIVER WATER IN QALAT SUKER CITY, DEC. 2019-APRIL, 2020, A SUSTAINABLE STUDY

Al- Gharraf River was chosen for this study as the main source of drinking water for most Thi-Qar Governorate residents. The water samples were chosen from three locations, when it entered Qalat Suker (Al-Nazim site) and in the middle of the city (the Bridge site) and when the river came out of the city (Al-Khammas site) each sample had three replicates for a period of five months from December 2019 to April 2020 as one measurement a month. Some physical and chemical properties, which are pH, electrical conductivity EC, turbidity, calcium, magnesium, and chloride ion, were studied. The distance between the entry point of the river and the outer point is about 8 km. The physical and chemical properties curves were plotted to show the changes in water characteristics during the months of the observation to compare the results with the international standards for water use.The results of the study indicated a rise in the concentration of chloride in some months due to industrial wastes, irrigation water, sewage, cleaning materials and organic waste, which is an important source of adding additional chloride ion in surface water and groundwater. The decline in some months may be due to increased rainfall. The study also showed that the concentration of magnesium ion within the allowed limits. Also, the present study also recorded a low concentration of calcium, it is clear that no any additional amounts of these ions added by the city activities. It is clear that the pH decreased in March and April which may because household waste and detergents, pHremains within the limits for human, animal and agricultural uses according to the World Health Organization and Iraqi standards. The water turbidity ranged from 1.77 NTU to NTU38.36. In December and January, the limits were within the permissible limits, while in (February, March and April), the water is considered unfit for human consumption, according to

Characteristics of biostability of drinking water in aged pipes after water source switching: ATP evaluation, biofilms niches and microbial community transition.

Delivering quality-changed water often contributes to the biological instability of drinking water distribution systems (DWDS). However, the potential effects of quality-changed water on the biostability within DWDS are not well understood, especially after water switching to quality-improved water. The objective of this study was to investigate the effects of quality-improved water on DWDS, focusing on the stability of biofilm. The practical aged-pipe was assembled into pipe reactors to simulate the effect of switching to quality-improve water. The adenosine triphosphate (ATP) concentration of bulk water in the pipe reactors increased from ∼1.2ng/L to almost above 5ng/L when fed water switching to TP 2. Biomass quantified by measuring ATP concentration confirmed that the risk of biofilm release through aged cast-iron (CI) pipe surfaces after water source switching. The changes in water characteristics due to quality-improved water source could cause bacteria release in DWDS at the initial period (at the first 7 days). However, the DWDS can establish the new stable phase after 42 days. Over time, biomass in the bulk water of the distribution system decreased significantly (The ATP concentration in the bulk maintains around 3ng/L) after 42 days, indicating the improvement of water quality. The biofilm was dominated by bacteria related to iron-cycling process, and at the genus level, Desulfovibrio had the highest relative abundance, however, it decreased significantly (from 48% to 9.3%) after water source switching. And there was a slightly increase in the fraction of iron-oxidizing bacteria (IOB) and siderophore-producing bacteria (SPB), but a relatively higher increase in nitrate-reducing bacteria (NRB), nitrobacteria (NOB), and iron-reducing bacteria (IRB) was observed. Taken together, these results and the corrosion morphology, indicate that pipe biofilm and corrosion were chemically and microbially stable after re-stability under water source switching. In addition, the bulk water environment showed a marked decrease in selected bacteria at genus level, including pathogenic species, indicating the improvement of quality in drinking water.

Adaptive Water Sampling Device for Aerial Robots

Water quality monitoring and predicting the changes in water characteristics require the collection of water samples in a timely manner. Water sample collection based on in situ measurable water quality indicators can increase the efficiency and precision of data collection while reducing the cost of laboratory analyses. The objective of this research was to develop an adaptive water sampling device for an aerial robot and demonstrate the accuracy of its functions in laboratory and field conditions. The prototype device consisted of a sensor node with dissolved oxygen, pH, electrical conductivity, temperature, turbidity, and depth sensors, a microcontroller, and a sampler with three cartridges. Activation of water capturing cartridges was based on in situ measurements from the sensor node. The activation mechanism of the prototype device was tested with standard solutions in the laboratory and with autonomous water sampling flights over the 11-ha section of a lake. A total of seven sampling locations were selected based on a grid system. Each cartridge collected 130 mL of water samples at a 3.5 m depth. Mean water quality parameters were measured as 8.47 mg/L of dissolved oxygen, pH of 5.34, 7 µS/cm of electrical conductivity, temperature of 18 °C, and 37 Formazin Nephelometric Unit (FNU) of turbidity. The dissolved oxygen was within allowable limits that were pre-set in the self-activation computer program while the pH, electrical conductivity, and temperature were outside of allowable limits that were specified by Environmental Protection Agency (EPA). Therefore, the activation mechanism of the device was triggered and water samples were collected from all the sampling locations successfully. The adaptive water sampling with Unmanned Aerial Vehicle-assisted water sampling device was proved to be a successful method for water quality evaluation.

Ancient roaches further exemplify ‘no land return’ in aquatic insects

Among insects, 236 families in 18 of 44 orders independently invaded water. We report living amphibiotic cockroaches from tropical streams of UNESCO BR Sumaco, Ecuador. We also describe the first fossil aquatic roach larvae (6 spp.; n = 44, 1, 1, 1, 1, 1) from the most diverse tropical Mesozoic sediments (Middle Jurassic Bakhar Fm in Mongolia, Kimmeridgian Karabastau Fm in Kazakhstan; Aptian Crato Fm in Brazil), and the Barremian Lebanese and Cenomanian Myanmar ambers. Tropic-limited occurrences are trophic- (biomass/litter-fall), structural- (diversity) and also abiotic-factor-dependent (high temperatures). Diverse Paleozoic aquatic eoblattids are here (re)described from the lower Permian sediments of Elmo, U.S.A. and Chekarda, Russia. They competed with true cockroaches to reach water prior to the Mesozoic. Due to different evolutionary rates or periodical changes in water characteristics, non-adapted terrestrial insects repeatedly invaded the aquatic realm with well adapted hydrobionts. Obscurely, most aquatic lineages still survive. In contrast with Crustacea, aquatic-terrestrial reversal is absent. A single principal lineage, namely of moths, ancestral to butterflies (origination of modern insects from ephemerans and dragonflies is questioned), possibly evolved from insects with aquatic immature stages, and none from aquatic adults. The rest of the orders are terrestrial-derived. The proposed reason for the lack of land return is the character of numerous aquatic adaptations related to reductions, which are unlikely to be resuppressed. The aquatic insect family/terrestrial insect family ratio over time reveals a sharp rise from the Late Carboniferous to Late Triassic followed by lasting stability. Diversification of aquatic insects seems consistent with a 62.05 ± 0.02 Ma periodicity.

Anomalous thermal properties of water

The relationships of coefficients of molecule diffusion, viscosity, thermal capacity, thermal conductivity and other properties of water as a function of temperature and pressure have been analyzed. It is shown that the main regularities of changes in water characteristics, including qualitative differences of its behavior from the rest of molecular liquids are stipulated by the peculiarities of covalent and hydrogen bonds.

Study of the dielectric function of aqueous solutions of glucose and albumin by THz time-domain spectroscopy

We report a study of aqueous solutions of glucose and bovine serum albumin using THz time-domain spectroscopy. To describe the permittivity of the solutions of these substances, we use a simplified model being applicable in the frequency range of . On the assumption that most of the water molecules become bound at high concentrations of glucose and protein in the solution, the changes in water characteristics are investigated. To improve the reliability of the results, the measurements are performed by two independent methods: the method of attenuated total internal reflection and the transmission method. Combination of the results obtained by these two methods allows expanding the spectral range towards lower frequencies.

Field evidence of the influence of aquatic macrophytes on water quality in a shallow eutrophic lake over a 13-year period

AIM: The main objective of this work is to describe the changes in water characteristics of a shallow subtropical lake, in periods with and without growing of macrophytes, related to periods of clear-macrophyte dominance and turbid-phytoplankton dominance states. METHODS: The study was conducted in Biguás Lake, in the south coastal plain of Brazil (32° 04' 43" S and 52° 10' 03" W). Samplings were carried out monthly between October 2000 and November 2013. The limnological variables measured in the water column were dissolved oxygen (DO), water temperature, pH, electrical conductivity (EC), chlorophyll-a, total nitrogen (TN), total phosphorous (TP) and suspended material (SM). Data were grouped according to periods with macrophyte growth dominance (MD) and without macrophytes, with phytoplankton dominance (PD), and applied t- tests among TP, TN, Chlorophyll-a and SM. During macrophyte growth we estimated the coverage (%) and biomass variation of plants. RESULTS: Over the 13 years, the lake was well oxygenated, alkaline, and with a temperature variation according to subtropical seasonality. The lower values of all of the limnological variables were verified during periods of macrophyte growth, characterizing periods of clear and turbid waters. CONCLUSIONS: The influence of aquatic macrophytes in improving water quality in this shallow lake during the studied period, reducing nutrient concentrations, chlorophyll-a and suspended material in water, favoring the maintenance of a clear water state, was verified.

Intermonsoon Variation of Physical Characteristics and Current Circulation along the East Coast of Peninsular Malaysia

Data from eight cruises spanning from 2002 to 2007 are used to investigate the seasonal changes in water characteristics and current circulation in southern South China Sea along the East Coast of Peninsular Malaysia. The surveys were made during two intermonsoon periods which are during March/April and September/October. In addition, monthly sea surface temperature from Moderate Resolution Imaging Spectroradiometer (MODIS) is used to provide wider coverage of spatial and temporal for seasonality study. Overall, the area shares different physical properties between the two seasons. During September/October temperature is lower and salinity is higher compared to the data during Mac/April/May. The current along the East Coast of Peninsular Malaysia also shows seasonality, with dominant current flow southward during Mac/April and northward during September/October.

Impact of elevated Ca2+/Mg2+ concentrations of reverse osmosis membrane desalinated seawater on the stability of water pipe materials

Hardness and alkalinity are known factors influencing the chemical stability of desalinated water. This study was carried out to investigate the effect of Ca(2+) and Mg(2+) on corrosion and/or scale formation on the surface of different water distribution pipe materials under tropical conditions. The corrosion rates of ductile iron, cast iron and cement-lined ductile iron coupons were examined in reverse osmosis (RO) membrane desalinated seawater which was remineralised using different concentrations of Ca(2+) and Mg(2+). The changes in water characteristics and the coupon corrosion rates were studied before and after the post-treatment. The corrosion mechanisms and corrosion products were examined using scanning electron microscope and X-ray diffraction, respectively. We found that the combination of Ca(2+) and Mg(2+) (60/40 mg/L as CaCO3) resulted in lower corrosion rates than all other treatments for the three types of pipe materials, suggesting that Ca(2+)/Mg(2+) combination improves the chemical stability of desalinated seawater rather than Ca(2+) only.

The Physico- Chemical Characteristics of Sheep Meat Post Mortem

گوشت گوسفند یکی از مهمترین منابع گوشت قرمز در کشورهای خاورمیانه محسوب و بنابراین اطلاع از ویژگیهای کیفی آن امری مهم تلقی می گردد. در بررسی حاضر خواص فیزیکوشیمیایی گوشت گوسفند طی یک دوره رسانیدن هفت روزه مورد بررسی قرار گرفت. نمونه ها از ناحیه فوقانی ران شامل ماهیچه های Biceps femoris. و Semimembranosus تهیه شدند. pH گوشت طی 24 ساعت نخست کاهش پیدا کرد و به میانگین 06/0±67/5 رسید. طی 6 روز بعد تغییرات معنی داری مشاهده نشد (05/0≥P). با افزایش زمان رسانیدن، توانایی نگهداری آب و افت پخت به طور معنی داری کاهش نشان دادند (05/0≥P). پروفیل دمایی پخت در مرکز طی روزهای مختلف پس از کشتار یکسان بود اما کل زمان مورد نیاز برای پخت نمونه ها در 24 ساعت پس از کشتار بطور معنی داری بالاتر از روزهای دیگر قرار داشت (05/0≥P). نتایج حاکی از آن بود که فرایند رسانیدن موجب بهبود ویژگیهای حسی آبداری، تردی و مزه در هر دو جنس نر و ماده می شود. رابطه ای معنی دار و مثبت میان امتیاز ویژگیهای حسی و امتیاز مربوط به پذیرش کلی مشاهده شد. در مورد تمامی ویژگیهای مورد بررسی، اختلاف معنی داری میان دو جنس نر و ماده وجود نداشت. واژه های کلیدی: رسانیدن، گوشت گوسفند، پروفیل دمایی پخت در مرکز، توانایی نگهداری آب، افت پخت، ارزیابی حسی

Hydrogen Peroxide Photocycling in the Gulf of Aqaba, Red Sea

The dynamics of hydrogen peroxide (H(2)O(2)) was investigated from December 2007 to October 2008 in the Gulf of Aqaba, which in the absence of H(2)O(2) contribution from biological production, rain and runoff, turned out to be a unique natural photochemical laboratory. A distinct seasonal pattern emerged, with highest midday surface H(2)O(2) concentrations in spring-summer (30-90 nM) as compared to winter (10-30 nM). Similarly, irradiation normalized net H(2)O(2) formation rates obtained in concurrent ship-board experiments were faster in spring-summer than in winter. These seasonal patterns were attributed to changes in water characteristics, namely elevated spring-summer chromophoric dissolved organic matter (CDOM). The role of trace elements in H(2)O(2) photoformation was studied by simultaneously measuring superoxide (O(2)(-)), Fe(II), and H(2)O(2) formation and loss in ambient seawater and in the presence of superoxide dismutase, iron and copper. O(2)(-) was found to decay fast in the Gulf water, with a half-life of 15-28 s, primarily due to catalytic reactions with trace metals (predominantly copper). Hence, H(2)O(2) formation in the Gulf involves metal-catalyzed O(2)(-) disproptionation. Added iron moderately lowered net H(2)O(2) photoformation, probably due to its participation in Fe(II) oxidation, a process that may also modify H(2)O(2) formation in situ.

NMR relaxometry and differential scanning calorimetry during meat cooking

By combining simultaneous nuclear magnetic resonance (NMR) T 2 relaxometry and differential scanning calorimetry (DSC) on pork samples heated to nine temperature levels between 25 and 75 °C, the present study investigates the relationship between thermal denaturation of meat proteins and heat-induced changes in water characteristics. Principal component analysis (PCA) on the distributed 1H NMR T 2 relaxation data revealed that the major changes in water characteristics during heating occur between 40 and 50 °C. This is probably initiated by denaturation of myosin heads, which however, could not be detected in the DSC thermograms obtained directly on the meat. In contrast, the DSC thermograms revealed endothermic transitions at 54, 65 and 77 °C, probably reflecting the denaturation of myosin (rods and light chain), sarcoplasmic proteins together with collagen and actin, respectively. Simultaneous modelling of DSC and NMR data by partial least squares regression (PLSR) revealed a correlation between denaturation of myosin rods and light chains at ∼53–58 °C and heat-induced changes in myofibrillar water ( T 2 relaxation time ∼10–60 ms) as well as between actin denaturation at ∼80–82 °C and expulsion of water from the meat. Accordingly, the present study demonstrates a direct relationship between thermal denaturation of specific proteins/protein structures and heat-induced changes in water mobility during heating of pork.

PH Dependence of the progression in NMR T(2) relaxation times in post-mortem muscle.

Continuous NMR T(2) relaxation measurements were carried out on seven rabbit longissimus muscle samples in the period from 25 min to 28 h post-mortem at 200 MHz for (1)H. To display differences in post-mortem pH progress and extent of changes in water characteristics during conversion of muscle to meat, three of the seven animals were pre-slaughter injected with adrenaline (0.5 mg/kg live weight 4 h before sacrifice) to differentiate muscle glycogen stores at the time of slaughter. Distributed analysis of T(2) data displayed clear differences in the characteristics of the various transverse relaxation components dependent on progress in pH, as did the water-holding capacity of samples 24 h post-mortem. This reveals a pronounced effect of the progressive change in pH on the subsequent development in physical/chemical states of water during the conversion of muscle to meat. Finally, the relaxation characteristics are discussed in relation to supposed post-mortem processes of protein denaturation.

Phytoplankton assemblages in the St. Lawrence River, downstream of its confluence with the Ottawa River, Quebec, Canada

Consistent differences in physical, chemical, and biological characteristics were observed along a transversal river section located 2 km downstream of the confluence of the Ottawa and the St. Lawrence rivers. Phytoplankton sampled at stations subject to the influence of the St. Lawrence River had a lower biomass, smaller cell volume, lower chlorophyll a, and lower taxa richness than did phytoplankton at stations influenced by the Ottawa River. The stations influenced by St. Lawrence River waters showed regular seasonal changes in phytoplankton biomass and composition, reflecting the major impact of the stratification and mixing cycles observed in the Great Lakes. By comparison, at the stations influenced by Ottawa River waters, monthly variations were found in biomass and composition correlated with temperature and water clarity, suggesting the effects of the watershed's morphology. A discharge reduction of 12% in the St. Lawrence River and 46% in the Ottawa River between summer 1994 and summer 1995 coincided, for stations in both water masses, with lower biomass and greater species richness and an increase in taxa that generate noxious smells and odours. Phytoplankton is recommended for use in monitoring the biological impacts of changes in water characteristics resulting from human activities and climate change in the Great Lakes watershed.

Phytoplankton assemblages in the St. Lawrence River, downstream of its confluence with the Ottawa River, Quebec, Canada

Consistent differences in physical, chemical, and biological characteristics were observed along a transversal river section located 2 km downstream of the confluence of the Ottawa and the St. Lawrence rivers. Phytoplankton sampled at stations subject to the influence of the St. Lawrence River had a lower biomass, smaller cell volume, lower chlorophyll a, and lower taxa richness than did phytoplankton at stations influenced by the Ottawa River. The stations influenced by St. Lawrence River waters showed regular seasonal changes in phytoplankton biomass and composition, reflecting the major impact of the stratification and mixing cycles observed in the Great Lakes. By comparison, at the stations influenced by Ottawa River waters, monthly variations were found in biomass and composition correlated with temperature and water clarity, suggesting the effects of the watershed's morphology. A discharge reduction of 12% in the St. Lawrence River and 46% in the Ottawa River between summer 1994 and summer 1995 coincided, for stations in both water masses, with lower biomass and greater species richness and an increase in taxa that generate noxious smells and odours. Phytoplankton is recommended for use in monitoring the biological impacts of changes in water characteristics resulting from human activities and climate change in the Great Lakes watershed.

The Danube Accident Emergency Warning System

Significant number of accidental water pollution incidents occurred during the past decades in the Danube River Basin, often having transboundary impacts. Growing needs arose at the important water users (first of all at drinking water intakes) along the rivers to get early warning about such incidents. The Danube Accident Emergency Warning System (DAEWS) was put into operation in April 1997, as a result of the short term priority action of the Environmental Programme for the Danube River Basin. The Danube Accident Emergency Warning System provides immediate information on sudden changes in water characteristics, like accidental river pollution incidents having transboundary effects, to assist the responsible authorities and water users in the downstream countries to make preventive measures in time. The countries where the system is now operational are (in the order of their location in the river basin): Germany, Austria, Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Romania, and Bulgaria. The National Centres of the system established within the programme in each of the co-operating countries are called as PIACs (Principal International Alert Centres), being in close contact with the national pollution control structures. To meet the requirements on fast information transmission capabilities, the system are equipped with a satellite communication system linked to local computer network between the units of the PIACs with information processing system, hazardous substances database, the Danube Basin Alarm Model for the simulation of pollution effects. International Operation Manual provides the standard operation technique in each country. Practical example of the serious chemical accidental spill in Hungary in May 1998 illustrates the operation of the DAEWS system.

The Danube accident emergency warning system

Significant number of accidental water pollution incidents occurred during the past decades in the Danube River Basin, often having transboundary impacts. Growing needs arose at the important water users (first of all at drinking water intakes) along the rivers to get early warning about such incidents. The Danube Accident Emergency Warning System (DAEWS) was put into operation in April 1997, as a result of the short term priority action of the Environmental Programme for the Danube River Basin. The Danube Accident Emergency Warning System provides immediate information on sudden changes in water characteristics, like accidental river pollution incidents having transboundary effects, to assist the responsible authorities and water users in the downstream countries to make preventive measures in time. The countries where the system is now operational are (in the order of their location in the river basin): Germany, Austria, Czech Republic, Slovakia, Hungary, Slovenia, Croatia, Romania, and Bulgaria. The National Centres of the system established within the programme in each of the co-operating countries are called as PIACs (Principal International Alert Centres), being in close contact with the national pollution control structures. To meet the requirements on fast information transmission capabilities, the system are equipped with a satellite communication system linked to local computer network between the units of the PIACs with information processing system, hazardous substances database, the Danube Basin Alarm Model for the simulation of pollution effects. International Operation Manual provides the standard operation technique in each country. Practical example of the serious chemical accidental spill in Hungary in May 1998 illustrates the operation of the DAEWS system.

A landsat study of the aquatic vegetation of the lake luodonjärvi reservoir, Western Finland

The hydrolittoral areas of the regulated Lake Luodonjärvi (63° 45′N lat., 22°50′E long.) on the eastern coast of the Gulf of Bothnia were studied by means of Landsat satellite imagery. It proved possible to detect spectral differences between different water areas. Seventeen aquatic complexes or types were classified separately on the basis of changes in water characteristics and depth, bottom quality and vegetational succession. The vegetation in summer 1983 was recorded in this way and reviewed against previous mappings in order to illustrate the multitemporal aspects of Landsat studies. Landsat classification could be used equally effectively in large area control, offering as it does the possibility of mapping the distribution of certain types of coastal environment over large areas by means of reflected radiation intensities.