Physical-chemical Point Of View Research Articles

Diatoms. A viable tool for quantifying surface water pollution

The current work focused on the water quality of the Bega and Timis rivers measured by two methods. One of them is the method by which the water was analyzed from a physical-chemical point of view, and the other aimed at quantifying the degree of water pollution by biological methods. In this sense, diatoms were used. In the study, samples of water and diatoms were taken using specific techniques from the Bega and Timis rivers, starting from near the area of their formation until near the border with Serbia. Four sampling points were chosen on the Timis River plus one sampling point on the Surgani River, which is a tributary of the Timis, and six sampling points on the Bega River. The points were chosen specifically, being located downstream of the major sources of pollution. In order to locate the points, information was collected from the studies carried out as part of an extensive monitoring that spanned several years. The abundance and diversity of diatom species were used to calculate the Biological Diatom Index (BDI) and the Saprobity Index (SI). These two indices provide valuable information about organic or heavy metal pollution of water bodies.

Physical-Chemical Characteristics of Three Soils and Their Effects on the Growth and Nutritional Status of Coffee Trees

Aims: The conversion of fallow land for the establishment of new orchards is now an alternative to Ivorian coffee growing, which has long been based on the extensive and shifting cultivation system favoured in the past by the abundance of forest reserves.
 Study Design: Thus, three fallow soils under coffee trees were studied from a physical-chemical point of view in order to determine their potential for the productivity of new coffee varieties (Coffea canephora Pierre, var. Robusta).
 Place and Duration of Study: The study was conducted on the National Centre of Agriculture Research (CNRA) research station at Abengourou, Divo and Man for six months, between June and November.
 Methodology: Soil samples and coffee leaves were collected and analyzed in the laboratory according to standard methods to determine their chemical status. Plant growth (height, crown diameter, number of orthotropic, number and length of plagiotropic internodes) was studied in relation to the physical-chemical characteristics of the soil.
 Results: The chemical potential of the soils was found to be low overall. Soil deficiency was characterized by low base saturation (less than 30%), organic matter, nitrogen and cation imbalance, as regard as potassium (K), calcium (Ca) and magnesium (Mg). Growth parameters of the coffee trees and their nutritional status were correlated with the physicochemical properties of the soil.
 Conclusion: In view of these results, sustainable coffee production requires an improvement in the level of soil fertility under coffee trees.

Dosimetric Double Network Hydrogel Based on Poly(vinyl-alcohol)/Phenylalanine-Derivatives with Enhanced Mechanical Properties

An innovative double network hydrogel based on poly(vinyl-alcohol) (PVA) cross-linked with glutaraldehyde (GTA) was obtained by the addition of self-assembling phenylalanine (Phe) derivatives with the aim to achieve improved mechanical-elastic properties exploitable to produce 3D dosimeters. The self-assembling ability in fibrous structures of Phe derivatives (FmocPhe-OH, A; FmocPhe-Phe-OMe, P) even within the PVA gel was proved by AFM and SEM imaging. The proposed matrices containing A and P were completely characterized from the physical-chemical point of view in order to deeply understand how the two molecules influenced the hydrogel properties. Mechanical tests proved that the addition of the Phe derivatives produce higher stiffness, toughness, and stretchability of the hydrogels. In particular, these properties appear in the peptide P matrix and could be appropriately tailored by regulating the concentration of the added molecule. Preliminary dosimetric studies were also performed by infusing the studied hydrogels with Fricke solution. The P type has been demonstrated to be suitable for dosimetric applications by avoiding any effect on the dose response of the hydrogel. This work presents an unconventional material that is able to provide clinicians and medical physicists with effective and reliable 3D dosimetric measurements for the development of anthropomorphic phantoms that mimic mechanical properties and the radiological response of human tissues.

Impact of soil from monoculture pine plantations on two anuran species from the Atlantic Forest: Odontophrynus reigi and Leptodactylus luctator

Monoculture tree plantations reduces landscape heterogeneity and the number and diversity of habitats available for species. Physical-chemical changes in soil may affect the ponds where tadpoles develop. This work aimed to study the effect on tadpoles of two species of frogs, Leptodactylus luctator (Ll) and Odontophrynus reigi (Or) exposed to soils from a pine plantation (PP), which were compared to tadpoles exposed to soils from Atlantic Forest, the native forest (NF). The impact of soils from both places on growth, development, antioxidant system and genetic damage of Ll and Or tadpoles were observed. A composite sample (5 kg) of soil was taken from the top 10 cm stratum in a 200 m transect in each site, with random plots of 50x50cm. In collected soil samples Organic Matter (OM), Organic Carbon (OC), and Total Nitrogen (TN) were determined. We conducted laboratory experiments, from 23 until 38 Gosner stages. During the experiment, pH and ammonium in the water were determined. Soil from NF presented higher content of OM, OC and TN, and water pH in PP was 0.2 units lower than in NF. Both species showed ≈60 % increase of catalase activity in PP, and ≈40 % increase of lipid peroxidation in NF. Ll tadpoles presented 10 times higher protein oxidation in PP than in NF, but Gosner stage was higher in NF. In NF the higher OM and OC in both species causes the increase of lipid peroxidation; and Ll responds to a stressor in PP that in Or is not observed. Or presented lower stress response towards PP soils, which indicates a tolerance towards this soil. The changes observed in soil chemistry, although not big from a physical-chemical point of view, affects the growth, development and oxidative stress of two species of anuran tadpoles from the NF, which can affect future populations and anuran diversity.

Natural calcium phosphates from circular economy as adsorbent phases for the remediation of textile industry waste-waters

Adsorption is one of the most important techniques for the remediation of textile industry wastewaters containing high concentrations of toxic dyes. Calcium phosphates (CaPs) have been advocated among the most promising adsorbent phases in virtue of their high dye adsorption potential, low production cost, and possible recovery from circular economy sources. In this paper, we investigated the application of synthetic CaPs (CaP–S) and two CaPs extracted from food by-products, namely from bone meal (CaP-BM) and fish bones (CaP-FM) for the removal of a model dye, copper phthalocyanine tri-sulfonic acid, also known as acid blue 185 (AB-185). All the materials were characterized from the physical-chemical point of view and used for the study of adsorption kinetic and isothermal adsorption of AB-185 at neutral, acidic and basic pH values. The best adsorption capacity was obtained for CaP–S, followed by CaP-BM and CaP-FM. Nonetheless, results showed that all the materials can be employed for removing AB-185 from wastewaters of textile industry, and we correlated dye removal efficiency to the adsorbent phase specific surface area (SSA) and ζ-potential, as well as to dye concentration and pH of wastewaters. Finally, as the process used to produce the studied CaPs affects their main final physical-chemical parameters and performance in terms of dyes removal, it is important to consider the variables of CaPs production process (e.g., temperature, time of treatment, grinding etc.), especially when CaPs are recovered from circular economy sources by thermal treatments of food-byproducts.

Bio-Evaluation of Groundwater Quality in the Souk Naamane and Ain M'lila region (Oum El Bouaghi, High Plain of Eastern Algeria

The present study was carried out in order to assess the quality of groundwater in the western region of Oum El Bouaghi district, (commune of Souk Naamane and commune of Ain M'lila). A total of 9 wells and 2 water springs were tested in the two communes over a period of eight months from October 2017 to May 2018. The fauna were sampled using two methods: the net phreatobiological and the baited trap method. Some physicochemical properties of the wells were measured during each campaign. 1237 individuals belonging to 47 families were recorded during the sampling. From a physical-chemical point of view, the analysis in main components indicates that the water is highly mineralized.

Polymer informatics for QSPR prediction of tensile mechanical properties. Case study: Strength at break.

The artificial intelligence-based prediction of the mechanical properties derived from the tensile test plays a key role in assessing the application profile of new polymeric materials, especially in the design stage, prior to synthesis. This strategy saves time and resources when creating new polymers with improved properties that are increasingly demanded by the market. A quantitative structure-property relationship (QSPR) model for tensile strength at break is presented in this work. The QSPR methodology applied here is based on machine learning tools, visual analytics methods, and expert-in-the-loop strategies. From the whole study, a QSPR model composed of five molecular descriptors that achieved a correlation coefficient of 0.9226 is proposed. We applied visual analytics tools at two levels of analysis: a more general one in which models are discarded for redundant information metrics and a deeper one in which a chemistry expert can make decisions on the composition of the model in terms of subsets of molecular descriptors, from a physical-chemical point of view. In this way, with the present work, we close a contribution cycle to polymer informatics, providing QSPR models oriented to the prediction of mechanical properties related to the tensile test.

In Vitro Physical-Chemical Behaviour Assessment of 3D-Printed CoCrMo Alloy for Orthopaedic Implants

In this study, a CoCrMo-based metallic alloy was manufactured using a 3D-printing method with metallic powder and a laser-based 3D printer. The obtained material was immersed in a simulated body fluid (SBF) similar to blood plasma and kept 2 months at 37 °C and in relative motion against the SBF in order to mimic the real motion of body fluids against an implant. At determined time intervals (24, 72, 168, 336, and 1344 h), both the metallic sample and SBF were characterized from a physical-chemical point of view in order to assess the alloy’s behaviour in the SBF. Firstly, the CoCrMo based metallic sample was characterized by scanning electron microscopy (SEM) for assessing surface corrosion and X-ray diffraction (XRD) for determining if and/or what kind of spontaneous protective layer was formed on the surface; secondly, the SBF was characterized by pH, electrical conductivity (EC), and inductively coupled plasma mass spectroscopy (ICP-MS) for assessing the metal ion release. We determined that a 3D-printed CoCrMo alloy does not represent a potential biological hazard in terms of the concentration of metal ion releases, since it forms, in a relatively short period of time, a protective CoCr layer on its exposed surface.

Effect of Agricultural Residues Based-Compost on the Yield of Amarantus hybridus L. (Amaranthaceae) in Gbado-Lite City, Nord-Ubangi (Democratic Republic of the Congo)

An experimental study was conducted in Gbadolite city to develop composts from peanut (Groundnut) and maize residues alone or combined. The study found that plots modified with compost based on peanut (Groundnut) residues combined with corn residues are of good quality compared to non-waste compost combined and unamended plots as indicated by the average values of plant height (91.9±0.79 cm vs. 54.0±1.35 cm), diameter at the collar (12.66±0.47 mm vs. 9.00±1.41 mm); number of leaves ( 20.6±0.47 vs. 15.6±0.47); leaf lengths (23.5±1.17 cm vs. 19.4±1.92 cm ); leaf widths (7.32±0.44 cm vs. 6.34±0.68 cm) yield per hectare ( 22.63±0.67T/ha vs 11.51±2.85 T/ha ). It is therefore desirable that compost be characterized from a physical-chemical point of view (pH, minerals, C/N ratio, etc.) and considers the production of other plants grown on this substrate in order to assess its effectiveness.

Regulating temperature of oil saturation with paraffins to avoid asphaltene, resin and paraffin substances deposition during oil production

In order to regulate temperature of oil saturation with paraffins to avoid asphaltene, resin and paraffin substances (ARP-S) deposition using thermal method as well as chemical reagents and additives implementation was considered. A particular attention is paid to the chemical composition of the produced hydrocarbons, as well as to the effect of individual high-molecular components of hydrocarbons during the extraction and further transportation at low temperatures and with a temperature gradient difference. The paper presents the influence of hydrocarbon composition on the development mechanism, the composition and the properties of ARP-S. The methods for the removal of deposits associated with the use of various additives and reagents, as well as the methods for the prevention of these sediments development are considered. A brief description of the main classes of chemicals used for the solution of ARP-S prevention and removal problem is given. It was shown that in order to select the most effective ways of organic substance sediment prevention and removal from the physical-chemical point of view, it is necessary to obtain an idea about the composition and the properties of the initial oil and the developed deposits.

Hypothetical Physics and Chemistry of Volcanic Eruptions: The Doorway to Their Prediction

This article presents a further development of the hypotheses concerning the possibility of predicting (“tectonic”) earthquakes [1]. Those hypotheses are based on the conversion of all types of released energy into heat and active chemical substances. One of the important sources of this phenomenon is the release of the latent energy trapped and stored during the Earth’s accretion. The latent energy of primordial hydrogen and helium escaping from the Earth’s core and lower mantle causes degassing processes [2] [3]. This latent energy converts into totally different types of chemical, electromagnetic and thermal energies of active compounds that are responsible for the major endogenic terrestrial processes. The dominating theories in seismology and volcanology are that an earthquake results from a sudden slip of a tectonic fault and that only magma and the gases contained in magma supply the volcanic energy resulting in the conclusions that earthquakes and eruptions are unpredictable. Volcanic eruption is considered herein to be a special case of the earthquake-process in which earthquake hypocenters rise to the Earth’s surface. A possible solution is proposed ([1] and herein) based on the analyses of the physicochemical processes as participants in earthquake and eruption preparations (foreshocks - major shock - aftershocks - volcanic eruptions) and on the characteristic rates of reflection of these processes on the Earth’s surface. Influences of Sun-Moon-tides and volcanic (“harmonic”) tremors are analyzed from physical-chemical point of view. The case of the 1980 eruption of Mount St. Helens and the proposed monitoring of the recommended additional data provides a way of selecting a complex of reliable earthquake and volcanic eruption precursors.

Valorization alternatives of colombian bee-pollen for its use as food resource - a structured review

Background: Pollen of honey-bee Apis mellifera L. is a product gathered for human consumption and marketed as a nutritional and functional resource. However, some studies indicate that it is necessary to develop transformation processes to modify the external structure of pollen, which is extremely difficult and prevents the nutrients and bioactive compounds to be completely digested in the gastrointestinal tract. The bee-pollen productivity in Colombia is up to five times higher than in countries traditionally recognized for its marketing, making this a valuable business opportunity. Objectives: To describe the chemical structure and the most important nutritional and functional components in bee pollen, as well as to understand the availability of compounds and some backgrounds reported for the opening of the bee-pollen grain, both in a natural and artificial manner. Methods: The literature search involved the use of different terms, alone or combined, by using logical operators; some terms were: pollen, beebread, bioactive and nutritional compounds, bioavailability, pollen structure, exine, fertilization. Selected search fields were the title or abstract of the publication in the following databases: Directory of Open Access Journals, Emerald, Pubmed, Redalyc, Scientific Electronic Library Online, Science Direct, Springer Journal, Taylor & Francis, Wiley Online Library. The selected literature was that found mainly between 2008 and 2014in Spanish and English. Results: The nutritional and functional composition of bee-pollen is widely reported; nevertheless, few studies on transformation processes to improve the availability of the compounds present in this product were found. The natural fermentation process occurred within the hive to obtain the product known as “bee-bread” is highlighted, since an emulation of this transformation could be developed in a controlled manner for a scaled production; despite this, further research in the involved biotechnological aspects is still required. Conclusions: Efforts have been made to characterize the bee-pollen from a physical-chemical point of view, but no significant progress in the development of processes of transformation has been reached. The future trends should aim at developing engineering processes emulating the phenomena occurred in nature where structural changes in the outer layer of bee-pollen can be achieved.

DEGREE OF WATER EUTROPHICATION IN THE TERMINAL BASIN OF THE DANUBE. CASE STUDY

Due to human activity, there are some changes in the composition of surface waters, especially near the industrial plants and cities. Wastewater, insufficiently treated, affects negatively the quality of the emissary they reach. The discharge of poorly treated municipal sewage and industrial surface waste water has serious consequences for the natural phenomenon of self-purification, water Borcea branch and the Danube are now reaching the limits of the natural possibilities of biogeochemical balance recovery. In the present study two sources of waste water were taken into discussion, with important contribution of pollutants reaching the terminal basin of the Danube from the Waste Water Treatment of CAƒlAƒraAŸi town and a meat processing plant, representative for the businesses in the county. The indicators followed in the study were: chemical consume of oxygen, biochemical consume of oxygen, ammonia nitrogen, total phosphorus. In recent months, by the rehabilitations that have been already made in the treatment plant, the water quality discharged into the environment improved, from physical chemical point of view. From the evolution of the main indicators analyzed, it is found out a decrease in content of organic substances and water eutrophication agents (total phosphorus and ammonium ion),  their  values ​​reaching nearer to the standards required by  the legislation in force.

Improved Performances of $\hbox{MgB}_{2}$ Conductor by Using of Innovative Amorphous and Nano-Structurated Boron

In this paper, we report about improved performances of amorphous and nano-structurated boron in MgB2 critical current density of wires and tapes. The boron produced by magnesiothermic reaction, using nano-structurated boron oxide, is used to synthesize nano-structurated MgB2 powders. These powders are used to produce several wires by ex-situ P.I.T. method. Here we applied only the ex-situ technique, in which our group is very well skilled. The same procedure can be applied to obtain in-situ P.I.T. tapes and wires as well. The boron and the MgB2 powders are characterized both from a physical-chemical point of view and from the superconductive point of view. We performed X-ray analysis to compare the home-made boron crystalline degree with respect to the commercial one. SQUID and transport measurements were done to compare the wire's critical current density behavior with respect to our past results using different boron.

Research on the Physical and Chemical Characterization of Meat Resulting from B.U.T. Big 6 Turkey Hybrid

Poultry occupied and continues to occupy an important place in human nutrition, position occupied thanks of its nutritional qualities. This paper presents results of a study concerning the quality of turkey meat stored under refrigeration. The biological material was represented by the principal muscular regions B.U.T. Big 6 hybrid groups. For the characterization of meat quality from physical-chemical point of view, the percentage of protein, fat, water, collagen in fresh meat (immediately after slaughter) from the major muscle groups were determined, as well as the pH determined after slaughter, during maturation, autolysis and alteration process. The results revealed differences in the average percentage of water determined by regions, the average being 69.8% established in the breast, 71.94% in the upper thigh, 70.58% in the inferior thigh and 70.76% in the wings. The dry substance registered average values of 30.2% in the breast, 28.06% and 30.43% in the superior thigh, respectively the inferior one and 33.23% in the wings. Regarding the evolution of pH, it showed statistically significant differences in measurements depending on the process. These investigations are part of a larger study whose primary goal is to characterize the chemical properties of the meat obtained from turkey hybrids destined for meat production.

Researches Concerning the Quality of some Semi-Smoked Meat Products Obtained in a Meat Processing Unit

Abstract. The purpose of the performed researche was to establish the quality of some meat products in casings belonging to the semi-smoked group obtained in a meat processing factory. In this respect, organoleptic and physical-chemical analysis have been performed on ten assortments belonging to the specified group of the meat products in casings. The obtained results highlight that, from organoleptic point of view the finished products are in compliance with the standard provisions excepting some assortments in which case were found some physical faults such as: wrinkled casings (in case of the Italian and pork salamis), the presence of conjunctive tissue on section (in case of the Victoria salami) or pork skin improperly minced (the Salajeni sausages), exuding fat at the ends of the bar-salamis (in case of the Crakauer salami), air holes under the casing (in case of the Trandafir sausages) or on section (in case of the Vara salami). These physical faults are caused by the non-observance of some technological parameters. The incidence of these faults does not exceed 12.8% of the total number of analyzed samples. From physical-chemical point of view the obtained values for the finished products are in accordance with the in force quality standards, excepting 10% from the total number of analyzed samples (small exceedings of the maximum admitted limit of the moisture content in case of the Vara, Italian and pork salamis and the salt content for the Populari sausages). There have been analysed the causes of these faults and the necessary measures to prevent occurrence of these faults and insuring the quality of the finished productsÂ

Theoretical calculation of partition coefficients of dimethoxypyrimidinylsalicylic acids

Despite their importance as herbicides, dimethoxypyrimidinylsalicylic acids has been poorly characterized from a physical-chemical point of view. This lack of information has prevented the assessment of their impact in the environment once they are released. In this study, environmentally important properties (free energy of solvation, Henry's law constant, octanol/air, and octanol/water partition coefficients) of 39 dimethoxypyrimidinylsalicylic derived compounds are calculated by density functional theory (DFT) methods at B3LYP/6-31G(d,p) level of theory using the Poisson-Boltzmann solvation model. These properties have not been reported previously for this family of compounds, neither experimentally or theoretically.

STUDIES REGARDING DETERMINATION AND ESTABLISHING THE VALIDITY OF BOILED AND SMOKED MEAT PRODUCTS

Underlining the validity problem can only be welcomed, given the conditions that in nowadays there doesnt exist a recipe without preservatives, antioxidants, colorants etc. Modern technology for meat products has a very important role in improving the quality of aliments, level of civilization and the prosperity of a country.In order to determine the validity of food products we have chosen as an example meat product as they have an equilibrated trophyne composition, a high biological value and special nutritional qualities.Using the cold air technologies in obtaining meat products ensures, together with the food additives, keeping of quality and nutritional characteristics of the final products.For this study we have chosen meat products from the group of boiled and smoked products: beer sausage. In the final we have analyzed the results of the experiment from the quality, microbiological and physical-chemical point of view. The quality exam referred to appreciate the aspect, color, taste, smell, consistency etc. The physical-chemical analysis determined humidity, salt, nitrates, Kreiss reaction and mg. NH3/100 g.

Systems Biology: an information-theoretic-based thermo-statistical approach

Systems Biology (system-level understanding in biological science), from the physical-chemical point of view, is involved with irreversible thermodynamics and nonlinear kinetic theory of open systems which are founded on nonequilibrium statistical mechanics. We describe a modern thermo-statistical approach for dealing with complex systems, in particular biological systems. We consider the case of a very peculiar complex behavior in open boson systems sufficiently away, from equilibrium, which appear to have large relevance in the functioning of biological systems. This is, on the one hand, the so-called Frohlich-Bose-Einstein-like condensation leading in steady-state conditions to the emergence of a particular case of quantum-large-scale coherent ordering, of the type of a selforganizing-synergetic dissipative structure. Moreover, additional complexity emerges in the form of propagation, in this condensate, of signals (information) consisting of nearly undamped and undistorted, long-distance propagating, solitary waves (the pseudoparticle soliton). It can be accompanied by a so-called Frohlich-Cherenkov cone of emission of polar vibrations, and it is also possible the formation of ¨ metastable states of the form of the so-called bioelectrets. These are phenomena apparently working in biological processes, which are presently gaining relevant status on the basis of eventually providing a large-scale quantum-coherent behavior in cytoskeletons of neurons and the conscious (non-computational) activity in the brain. Emphasis is centered on the quantum-mechanical-statistical irreversible thermodynamics of these open systems, and the informational characteristics of the phenomena. Ways for their experimental evidencing are pointed out and discussed.

On the Self-Assembly of Monoolein in Mixtures of Water and a Polar Aprotic Solvent

A new kind of lipid/polymer composite particle, consisting of a biodegradable polymer matrix with well-defined lipid domains, has been created. The lipid used is the water-swelling lipid monoolein (MO), which forms a reversed bicontinuous cubic diamond structure in aqueous solutions. The polymer is poly(d,l-lactide-co-glycolide) (PLG), which degrades into water-soluble monomers through hydrolysis. This new particle might be a good alternative for encapsulation of active substances intended to be released over a longer period of time, i.e. sustained/retained/controlled release.To prepare such particles can be difficult. Suitable phase behaviour and a solvent with the right properties are needed. For this reason, the phase behaviours of several different lipid/polymer/solvent/water systems have been explored. From the phase behaviour of a suitable system (i.e. MO/PLG/ethyl acetate/water), a route for formation of lipid/polymer composite particles has been deduced. Particles have been formed and distinct, water-swelling, lipid domains have been confirmed by characterization by means of confocal laser scanning probe microscopy (CLSM). The sample preparation process has been automated and a method based on using a robotic liquid handler has been developed. Phase diagrams have been determined by examination of macroscopic behaviours and the microstructures of the phases have been studied by small- and wide-angle X-ray scattering (L3, V2, Lα, L), nuclear magnetic resonance self-diffusion (L, L3), viscosimetry (L) and rheology (L). Several different theoretical models have been applied for interpretation of the results. For example, the swelling of the reversed bicontinuous cubic phases and the sponge phase have been modelled by applying the theory of infinite periodical minimal surfaces, the sponge phase has been shown to be bicontinuous according to the theory of interconnected rods and the phase behaviour of the polymer has been described by the Flory-Huggins theory. The main focus of this work (4/5) concerns phase studies in multicomponent systems from a physical-chemical point of view.