Low Conductivity Values Research Articles

Fabrication of Polyvinylpyrrolidone Nanofibers with Green Solvents

In this study, biocompatible Polyvinylpyrrolidone (PVP) nanofibers were produced with ultra-pure water, rose water, lavender water, ethanol, acetone and acetic acid with green electrospinning approach. Polymer solutions were characterized with conductivity, surface tension and viscosity measurements. Morphological analyzes were carried out with Scanning Electron Microscope (SEM). Conductivity, surface tension and viscosity results of PVP/ ultra-pure water, rose water and lavender water solutions were similar. On the other hand, PVP/acetic acid solution has the highest viscosity and lowest conductivity values and PVP/ethanol solution has got the lowest surface tension. In addition; the lowest average fiber diameters were obtained from ultra-pure water, rose water and lavender water solvents but there are some beads on the nanofiber structure. The smoothest nanofibers without beads were obtained from PVP/ethanol but it was observed that average fiber diameter is about 724 nm higher than other PVP solutions. Therefore, ethanol was chosen as a co-solvent to enhance fiber morphology for second part of study. Moreover; the relation between solution conductivity, nanofiber diameter and web diameter were determined and it was found that nanofibrous surface diameter increases and fiber diameter decreases with the increase of solution conductivity.

Soil Morphology, Physico-chemical Properties, Classification and Potential of Selected Soils in Kenya

Four soil profiles (Yala, Galana, Baringo and Bondo) that represent different ecology, physiography and pedological variability were described to study their morphology, soil physico-chemical characteristics and to classify them using two internationally known soil classification systems. Soil samples were taken from designated pedogenic horizons for physical and chemical analysis in the laboratory. These soils are deep to very deep (> 110 cm) and well-drained except in Galana which was imperfectly drained, with varying textures. In Bondo, the soils are moderately acid (pH 5.6 – 6). In Baringo, the soil profile is acidic (< 5.0) while in Galana moderately alkaline (pH 7.3 - 8.3) and Yala soils are moderate to strongly acid (5.1 - 5.7). The organic carbon (< 0.6%) and organic matter levels (1 – 2%) were low and decreased down the profiles in all. The soils have low to moderate fertility. The base saturation of the studied soils is rated as very high (> 80%) in Galana and Baringo and low (< 50%) in Yala and Bondo pedons. The soils are non-saline as indicated by the low values of electrical conductivity (< 1.7dS/m) in the pedons. The soils are non-sodic (ESP < 6%) in Bondo and Yala, however moderately sodic (ESP 11-15%) in Galana and Baringo. Ochric horizon was the main diagnostic epipedon while ferralic, argillic and cambic horizons were the diagnostic B horizons. According to USDA Soil Taxonomy, the soils were classified as Typic Haplustox (Yala), Typic Haplocalcids (Galana), Typic Eutrudepts (Baringo) and Plinthic Haplustults (Bondo) corresponding to Haplic Ferralsols, Luvic Calcisols, Haplic Cambisol and Cutanic Plinthic Acrisols in the WRB for Soil Resources. The general fertility of the soils of the areas is discussed highlighting their potentials and constraints.

Influence of hydraulic properties on physically modelling slope stability and the definition of rainfall thresholds for shallow landslides

Physically-based models are recognized as a good tool for slope stability analysis and have been implemented for the definition of rainfall thresholds for landslides. In this study, a methodology for estimating rainfall intensity and duration thresholds for shallow sliding failure, using the physical model TRIGRS, was implemented in a tropical mountainous basin of the Valle de Aburrá (Colombia). The variation of pressure head and factor of safety during different rainfall events and hydraulic conditions is studied for specific grid cells. Steady state and a maximum pressure head were reached for each grid cell regardless of the different rainfall intensities and hydraulic conductivities simulated, but the time in which this condition is reached depends on these variables and occurs faster for steeper slopes. The influence of hydraulic properties on the stability results and the position of the rainfall intensity and duration thresholds were studied with parametric analysis. Very low values of saturated hydraulic conductivity do not allow rainfall intensity and duration thresholds to be developed. The rainfall threshold position also has a greater variation with respect to the parameters of the soil water retention curve and the initial infiltration rate (or long-term background rainfall rate) for low values of saturated hydraulic conductivity.

CBMT-14. THE DIELECTRIC PROPERTIES OF BRAIN TUMOR TISSUE

Abstract INTRODUCTION Recently, tumor treating fields (TTFields) were established for the treatment of newly diagnosed GBM. One of the most crucial parameters defining the treatment efficacy of TTFields is the electric field intensity, which depends on the dielectric properties of the tumor tissue. In this study we determined the dielectric properties of brain tumors by analyzing resected tissue following a fast acquisition protocol. To account for the intratumoral heterogeneity, different regions of the tumor were analyzed separately. METHODS A cohort of 84 patients with tumors of different histology have been recruited. Tissue probes were acquired from the vital tumor area and perinecrotic compartment. The tissue was measured immediately to avoid artifacts. A fragment was dissected from each tissue sample and was placed into a cylindrical cell with a known diameter. The impedance was recorded at frequencies 20Hz-1MHz using a software specifically developed for this study, which controls the LCR meter. The measured impedance was translated into dielectric properties of the sample (conductivity and relative permittivity) based on the parallel plate model, the recorded complex impedance and the geometry of the samples. Each tissue probe was fixed, H&E stained and histologically analyzed. RESULTS We found significant differences between the conductivity of different types of tumors with meningiomas showing the lowest conductivity (mean conductivity [S/m]: 0.193; range: 0.327 – 0.113) and GBM tissue exhibiting the highest conductivity values (mean conductivity [S/m]: 0.402; range: 0.893 – 0.157). Consistently, the perinecrotic areas displayed lower conductivity values compared to the solid tumor compartments. Also, we found a significant intratumoral heterogeneity in tumors of one specific histological diagnosis. CONCLUSION The dielectric properties of intracranial tumors appear to be depending on histological class and malignancy grade and show significant intratumoral heterogeneity. These results may allow a more precise modelling of electric field intensity distribution within the tumor.

Experimental study of a new ecological building material for a thermal insulation based on waste paper and lime

In the aim of the valorisation of waste paper, an experimental study of a new biocomposite (AWPL) dedicated to building based on Aggregates of Waste Paper and Lime is performed. The waste paper used in this work is transformed to Aggregates of Waste Paper (AWP), the physical, thermal and morphological properties were carried out. Five combinations of (AWP – Lime) have been prepared and the weight ratios of lime used are 20, 30, 40, 50, and 60 wt% correspond. Experimental investigations of physical, mechanical, thermal and morphological characterizations of AWPL were carried out in order to determine: the apparent density, the open porosity, the water absorption, the ultrasound pulse velocity, the flexural and compressive strengths and the thermal conductivity. Furthermore, a characterization by Scanning Electron Microscopy (SEM) was realized to observe the AWP/lime bond. The results of characterization of AWPL show good mechanical properties as flexural and as compressive, these results are confirmed by the analysis SEM, that shown good adhesion of the AWP/Lime interface. The thermal characterization tests of AWPL have shown an important thermal insulation capacity linked to the low values of the thermal conductivity, these low values can be explained by the high porosity of AWPL. As a result, the AWPL could be classified as a structural and thermal insulation material for buildings according to the RILEM classification.

Investigations on micro hardness, electrical and thermal conductivity of AA7075 surface hybrid composites produced through friction stir processing

High strength, minimum thermal and electrical conductivity are the major requirements of aircraft applications which could be obtained by micro-structural modifications of the composites with particulate reinforcements. The proposed work focus the analysis on the behavior of micro hardness, coefficient of thermal expansion, thermal and electrical conductivity of AA7075 fabricated by friction stir processing with different weight ratios of Al2O3 and SiC. Different surface hybrid composites are formed by varying the weight ratios. It ensures the formation of fine grained structure and decrease in thermal and electrical conductivity values with addition of higher hardness. During the friction stir processing, the working temperature is identified between 99.4 and 316.6 °C for the proposed composites, which shows 15.6% and 49.8% that of the melting point of AA7075 (635 °C). Experimental investigation on thermal conductivity and electrical conductivity has been conducted under different heat input values through varying the applied voltage from 25 to 225 V. The observation shows surface hybrid composites depicts lower conductivity values with Al2O3 and SiC particles due to variation in energy level of electrons and phonons. Among the observations, the specimen S5 reinforced with equal weight ratios of Al2O3 and SiC yields the maximum micro-hardness of about 265 VHN and lower coefficient of thermal expansion of about 13 μm m−1 °C. This is due to the reinforcement behavior and formation of Al4C3 intermetallics. The morphological analysis also supports the requirements of aircraft components.

Synthesis of Carbon Dielectric Composite from Candlenut Shell (Aleurites moluccana)

Dielectric materials have attracted attention cause their potential applications such as energy storage devices and sensors. The biggest issues in the synthesis of dielectric materials reside in improving dielectric properties. In our work, a carbon dielectric composite material was successfully synthesized with PEG 4000 and PEG 6000 matrices respectively. The dielectric properties of candlenut shell carbon based composites filled with PEG 4000 and PEG 6000 were investigated. Conductivity of carbon decreases along with the addition of the matrices. The lowest conductivity value was obtained from Carbon / PEG 6000 material (0.52 – 0.91) x 10−8 S / cm in the measurement range of 103 Hz - 104 Hz. This is due to the small carbon porosity (33.14%) and the addition of the matrices causing a decrease in the reactive surface area of the carbon.

Chemical and pharmacological aspects of novel hetero MLB complexes derived from NO2 type Schiff base and N2 type 1,10-phenanthroline ligands

A series of hetero ligand MLB complexes (1–5) were synthesised from tridentate NO2 type Schiff base [H2L: (E)-2-((2-hydroxy-4-methoxyphenyl)(phenyl)methyleneamino)benzoic acid; derived from 2-hydroxy-4-methoxybenzophenone and 2-aminobenzoic acid] and bidentate N2 type 1,10-phenanthroline (B: phen) ligands. The structural characterization of the synthesised MLB complexes were carried out via analytical as well as various spectral studies. Additionally, the low molar conductance values (Λm = 14–22 Ω−1 cm2 mol−1) imply that the complexes (1–5) are non-electrolytes. The obtained results reinforce that stoichiometry of the mononuclear hetero ligand complexes can be represented as [M(II)-Schiff base(L)-phen(B)·H2O] and both H2L and (B) ligands can act as tri and bidentates respectively. Moreover, both the ligands bind with metal(II) ions to build a stable six, six, five membered chelate rings with octahedral geometry. The existing solvent water molecule is confirmed from thermal as well as vibrational analysis. Their microcrystalline nature and uniform surface morphology were confirmed by both powder XRD and SEM studies. 3D molecular modeling and analysis of NiLB and CuLB complexes (3 and 4) were also studied. Mn(II), Ni(II) and Cu(II) complexes (1, 3 and 4) strongly interact with DNA through intercalation binding with strong binding constant values. The obtained Kapp values were 5.23, 4.98, 6.36, 7.21 and 4.86 × 105 mol−1 for MLB complexes (1–5) respectively and the negative Δ‡G values shown that all the complexes are strongly interact with DNA in a spontaneous manner. Further, remarkable biological, antioxidant and DNA activities were remarkably exhibited by MnLB, NiLB and CuLB complexes.

Electrofishing in streams of low water conductivity but high biodiversity value: Challenges, limits and perspectives

AbstractElectrofishing in streams of low water conductivity has technical limitations leading to the widespread use of poison fishing. In theory, provided a high enough voltage gradient can be created in water, electrofishing should be possible in all but the lowest of conductivities (<10 µS/cm). Using custom‐made equipment delivering up to 1,500 V DC, tests were carried out in French Guiana on 27 streams with water conductivity as low as 16 µS/cm. Approximately 5,800 fish of 93 species were captured, with an electrofishing mortality rate of 1.83%. Poison treatments were used within enclosed sections to assess how efficient multiple pass electrofishing removal is when assessing species richness and population number. The Chao II estimator on 2 electrofishing passes gave the best results for species richness, but rare species can elude electrofishing. Estimates of total fish abundance (i.e. all species pooled) were possible with the use of depletion models. Capture efficiencies by species were highly biased, however, and abundance could be underestimated for the most difficult species to catch. These results show that with the right equipment and settings, electrofishing can be an efficient alternative to poison fishing surveys in small tropical streams of low water conductivity but high biodiversity value.

P11.50 The dielectric properties of brain tumor tissue

Abstract BACKGROUND Recently, tumor treating fields (TTFields) were established for the treatment of newly diagnosed GBM. One of the most crucial parameters defining the treatment efficacy of TTFields is the electric field intensity. The dielectric properties of the normal intracranial compartments are well established, allowing the prediction of the electric field distribution. In contrast, there is no data available about the dielectric properties of brain tumor tissue. In this study we determined the dielectric properties of brain tumors by analyzing resected tissue following a fast acquisition protocol. To account for the intratumoral heterogeneity, different regions of the tumor were analyzed separately. MATERIAL AND METHODS A cohort of 84 patients with tumors of different histology and malignancy grade have been recruited (meningioma: n=26; brain metastases n=18; low grade glioma n=6; glioblastoma n=34). Tissue probes were acquired whenever possible from the vital tumor area, and perinecrotic compartment identified intraoperatively using neuronavigation, intraoperative ultrasound and fluorescence guidance. After acquisition, the tissue was measured immediately to avoid artifacts induced by temperature change, differences of fluid composition as well as post resection ischemia. A fragment was dissected from each tissue sample and was placed into a cylindrical cell with a known diameter. Two parallel electrodes were placed on both sides of the sample and the thickness of the tissue was measured using a micrometer. The impedance was recorded at frequencies 20Hz-1MHz using a software specifically developed for this study, which controls the LCR meter (Keysight Technologies, Santa Rosa, USA). The measured impedance was translated into dielectric properties of the sample (conductivity and relative permittivity) based on the parallel plate model, the recorded complex impedance and the geometry of the samples. Each tissue probe was fixed, H&E stained and histologically analyzed. RESULTS We found significant differences between the conductivity of different types of tumors with meningiomas showing the lowest conductivity (mean conductivity [S/m]: 0.193; range: 0.327 - 0.113) and GBM tissue exhibiting the highest conductivity values (mean conductivity [S/m]: 0.402; range: 0.893 - 0.157). Consistently, the perinecrotic areas of tumors displayed lower conductivity values compared to the solid tumor compartments. Also, we found a significant intratumoral heterogeneity in tumors of one specific histological diagnosis. CONCLUSION The dielectric properties of intracranial tumors appear to be depending on histological class and malignancy grade and show significant intratumoral heterogeneity. These results may allow a more precise modelling of electric field intensity distribution within the tumor.

Directionally controlled open channel microfluidics

Free-surface microscale flows have been attracting increasing attention from the research community in recent times, as attributable to their diverse fields of applications ranging from fluid mixing and particle manipulation to biochemical processing on a chip. Traditionally, electrically driven processes governing free surface microfluidics are mostly effective in manipulating fluids having characteristically low values of the electrical conductivity (lower than 0.085 S/m). Biological and biochemical processes, on the other hand, typically aim to manipulate fluids having higher electrical conductivities (>0.1 S/m). To circumvent the inherent limitation of traditional electrokinetic processes in manipulating highly conductive fluids in free surface flows, here we experimentally develop a novel on-chip methodology for the same by exploiting the interaction between an alternating electric current and an induced thermal field. We show that the consequent local gradients in physical properties as well as interfacial tension can be tuned to direct the flow toward a specific location on the interface. The present experimental design opens up a new realm of on-chip process control without necessitating the creation of a geometric confinement. We envisage that this will also open up research avenues on open-channel microfluidics, an area that has vastly remained unexplored.

Influence of degree of crystallinity on DC-conduction of polypropylene

Aim of this work was to study how degree of crystallinity influences the DC conduction characteristics of capacitor grade polypropylene (PP). PP pellets were pressed to 0.3 mm plates using two different cooling rates in order to vary the degree of crystallinity. The DC conduction currents were measured at 50 and 70 °C at 8-55 kV/mm. 3 h polarization and 15 h depolarization times were used. It turned out that temperature and the dielectric stress played a more dominant role regarding DC-conductivity than the obtained ~4 wt-% difference in crystallinity. Especially at 39-55 kV/mm, when temperature increased from 50 to 70 °C the DC-conductivity increased 10-15 times. There was however a trend related to the degree of crystallinity: the increase in crystallinity (more slowly sample cooling) led to lower conductivity values.

Synthesis, characterization and biological studies of cobalt(II), nickel(II), copper(II) and zinc(II) complexes of vanillin-4-methyl-4-phenyl-3-thiosemicarbazone

Complexes of vanillin-4-methyl-4-phenyl-3-thiosemicarbazone with cobalt(II), nickel((II), copper(II) and zinc(II) metal ions were synthesized and characterized by elemental analysis, molar conductance, magnetic moment, infrared spectra, electronic spectra, 1H and 13C NMR, mass spectrum and thermal analysis. The low molar conductance values indicate that all the complexes are non-electrolytes. Spectral studies indicate that the ligand act in a tridentate manner coordinating with the metal ion through sulphur, oxygen and nitrogen atoms. Based on magnetic moment measurements, spectral studies and thermal analysis, suitable geometry was proposed for the metal complexes. Thermal stability of the complexes was ascertained on the basis of thermo gravimetric analysis and the lattice parameters, space group and grain size of the ligand and complexes were determined by using powder XRD measurements. Surface morphology of ligand and complexes were studied using SEM analysis. Antimicrobial studies were carried out against gram-positive, gram-negative bacteria and two fungal pathogens. Vanillin-4-methyl-4-phenyl-3-thiosemicarbazone and its cobalt(II), nickel(II), copper(II) and zinc(II) complexes were synthesized and characterized and suitable geometry was proposed. All complexes except copper complex were stable up to 280 °C. The ligand and complexes belong to monoclinic crystal system with different space groups. Copper and zinc complexes of vanillin thiosemicarbazone were found to possess high antibacterial and antifungal activity.

A novel variant of the H-Φ field formulation for magnetostatic and eddy current problems

PurposeThe paper presents a new variant of the H-Φ field formulation for solving 3-D magnetostatic and frequency domain eddy current problems. The suggested formulation uses the vector and scalar tetrahedral elements within conducting and non-conducting domains, respectively. The presented numerical method is capable of solving multiply connected regions and eliminates the need for computing the source current density and the source magnetic field before the actual magnetostatic and eddy current simulations. The obtained magnetostatic results are verified by comparison against the corresponding results of the standard stationary current distribution analysis combined with the Biot-Savart integration. The accuracy of the eddy current results is demonstrated by comparison against the classical A-A-f approach in frequency domain.Design/methodology/approachThe theory and implementation of the new H-Φ magnetostatic and eddy current solver is presented in detail. The method delivers reliable results without the need to compute the source current density and source magnetic field before the actual simulation.FindingsThe proposed H-Φ produce radically smaller and considerably better conditioned equation systems than the alternative A-A approach, which usually requires the unphysical regularization in terms of a low electric conductivity value within the nonconductive domain.Originality/valueThe presented numerical method is capable of solving multiply connected regions and eliminates the need for computing the source current density and the source magnetic field before the actual magnetostatic and eddy current simulations.

Synthesis, Physico-chemical and Antimicrobial Studies on Metal (II) Complexes with Schiff Base Derived from Salicylaldehyde and 2,4-Dinitrophenylhydrazine

Schiff base derived from salicylaldehyde and 2,4-dinitrophenylhydrazine was synthesized. Its Mn(II) and Fe(II) complexes (MnL2 and FeL2) were synthesized by refluxing the metal (II) chlorides with the Schiff base. All the compounds were characterized by melting point/decomposition temperature, solubility, molar conductance, magnetic susceptibility infrared analysis and UV - visible spectrophotometry. The composition of the complexes has been found to be 1:2 (Metal-Ligand) ratio. The complexes have low molar conductance values 6.39 -6.59 ohm-1 cm2 mol-1 indicating non-electrolytes. The Schiff base and its metal (II) complexes were screened for antibacterial activity against five bacterial isolates Escherichia coli, Proteus mirabilis, Klebsiella pneumonia, Pseudomonas aureginosa and Staphylococcus aureus and three fungal isolates Fusarium solani, Aspergillus fumigates and Candida Albicans using good method. The results revealed that the complexes showed higher activity against the microorganisms compared to the Schiff base.

Abstract 4031: The dielectric properties of brain tumor tissue

Abstract Introduction: Recently, tumor treating fields (TTFields) have been established as for the treatment of newly diagnosed GBM1. One of the most crucial parameters defining the treatment efficacy of TTFields is the electric field intensity. The electric properties of the normal intracranial compartments are well established, allowing the prediction of the electric field distribution. In contrast, there is no data available about the electric properties of tumor tissue. In this study we determined the dieclectric properties of brain tumors by analyzing resected tissue following a fast acquisition protocol. To account for the intratumoral heterogeneity, different regions of the tumor were sampled and analyzed separately. Methods: A cohort of thirty patients with tumors of different histology and malignancy grade have been recruited (meningioma: n=11; brain metastases n=7; low grade glioma n=6; glioblastoma n=6). Tissue probes were acquired whenever possible from the vital tumor area, and perinecrotic compartment identified intraoperatively using neuronavigation, intraoperative ultrasound and fluorescence guidance. From each region, five tissue probes were sampled. After acquisition, the tissue was measured immediately to avoid artifacts induced by temperature change, differences of fluid composition as well as post resection ischemia. A fragment was dissected from each tissue sample and was placed into a cylindrical cell with a known diameter. Two parallel electrodes were placed on both sides of the sample and the thickness of the tissue was measured using a micrometer. The impedance was recorded at frequencies 20Hz-1MHz using a software specifically developed for this study, which controls the LCR meter (Keysight Technologies, Santa Rosa, USA). The measured impedance was translated into dielectric properties of the sample (conductivity and relative permittivity) based on the parallel plate model, the recorded complex impedance and the geometry of the samples. Each tissue probe was fixed, H&E stained and histologically analyzed for tumor cell count and specific tissue features. Results: After receiving a positive ethics votum, the first 30 patients were recruited. As a reference, grey and white matter tissue samples from mouse brains were used. We found significant differences between the tumor entities with meningiomas showing the lowest and GBM tissue the highest conductivity values. Consistently, the perinecrotic areas displayed lower conductivity values compared to the solid tumor compartment. Also, we found a significant heterogeneity in the dielectric properties within one tumor. Conclusion: The dielectric properties of intracranial tumors appear to be depending on histological class and malignancy grade and show significant intratumoral heterogeneity. These results may allow a more precise modelling of electric field intensity distribution within the Tumor. Citation Format: Martin A. Proescholdt, Amer Haj, Christian Doenitz, Alexander Brawanski, Zeev Bomzon, Hadas Sara Hershkovich. The dielectric properties of brain tumor tissue [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4031.

Quantitative Structure-Toxicity Relationship analysis of combined toxic effects of lignocellulose-derived inhibitors on bioethanol production

This study performed a Quantitative Structure-Toxicity Relationship (QSTR) model to evaluate the combined toxicity of lignocellulose-derived inhibitors on bioethanol production. Compared with all the control groups, the combined systems exhibited lower conductivity values, higher oxidation-reduction potential values, as well as maximum inhibition rates. These results indicated that the presence of combined inhibitors had a negative effect on the bioethanol fermentation process. Meanwhile, QSTR model was excellent for evaluating the combined toxic effects at lower ferulic acid concentration (([1:4] × IC50)) and (([1:1] × IC50)), due to higher R2 values (0.994 and 0.762), lower P values (0.000 and 0.023) and relative error values (less than 30%). The obtained results also showed that the combined toxic effects of ferulic acid and representative lignocellulose-derived inhibitors were relevant to different molecular descriptors. Meanwhile, the interactions of combined inhibitors were weaker when ferulic acid was at low concentration ([1:4] × IC50).

PEMBUATAN DAN KARAKTERISASI KOMPOSIT LiBOB/MgCl2 DENGAN METODE SOLID STATE REACTION

The manufacture and characterization of the lithium bus Composite (oxalate) borate with the addition of magnesium chloride (LiBOB/MgCl2). Electrolytes as a media transfer ion battery, plays an important role in the charge-discharge process of lithium ion batteries. The basic ingredients used in the study are lithium hydroxide (LIOH), Borid acid (H3BO3), Our acid dehydrate (H2C2O4 • 2H2O) and magnesium chloride hexahydrate (MgCl2 • 6H2O). The method used in this research is solid state reaction or known as solid-solid method. Based on the results of the XRD characterization, shows the peaks of LiBOB experiencing a shift after being added with 2.5%; 5% and 7.5% MgCl2 • 6H2O, in addition it also raises new peaks of magnesium. While the spread of the material is blown the sample appears evenly with the SEM-EDX test, however there are some elements that are experiencing clotting. And the FTIR test showed a change in the frequency of each mass increase of MgCl2 • 6H2O, but did not cause peak changes in each sample. In the EIS test results, obtaining a low electrical conductivity value, due to agglomeration of the material after the addition of elemental magnesium that is ionic. Thus also causes the diffusion of ions to lower.

Bacterial Cellulose Applied to the Production of an Electrical Insulating Biomaterial

Biotechnology is the science that in the future will revolutionize the production of biomaterials for the markets, one of its most promising products is bacterial cellulose (BC). The BC has a high degree of purity, because it is not associated with other components such as lignin and hemicellulose of vegetable cellulose and, due to its nanofibrillar network in 3D, it is able to absorb water and has high tensile strength. Other characteristics, such as biocompatibility and biodegradability, result in the renewable character and in a wide range of technological applications, such as the manufacture of transparent / translucent nanocomposites and, in particular, biomedical applications, such as the production of dressings for the recovery of burned skin, where membranes release of drugs through the skin, polymeric materials for bone repair repair and cartilage, as well as several other technological areas and as reinforcement material in transparent / translucent nanocomposites. The BC membrane has been studied aiming at the usability in the production of garments, accessories and high value-added textile products and in the active packaging sector to avoid or identify contamination of food. In the biomaterials sector, numerous BC blends and composites have been synthesized to overcome their limitations and increase their applications. BC blends have antimicrobial, healing, conductive, magnetic and optical properties. The morphological and electrical characterization of BCs was the objective of this work. The BC production was carried out using agroindustrial residue. The biomaterial was morphologically characterized by MEV before and after impregnation with PHB. The incorporation of PHB into BC served to maximize the properties and physico-chemical and insulating biomaterial. Conductivity values ??compatible with semiconductors were identified for BC. The bio-nanoblend of BC + PHB also showed low conductivity value, similar to pure PHB. All the samples showed IxV behavior that suggests that the samples are

Assessment of trace metal contamination in peri-urban soils in the region of Kenitra - Morocco

<p>The spatial distribution of trace metals in peri-urban soils from Kenitra city (Morocco) was investigated. A total of 10 soil samples (0-20 cm depth) were collected from the studied area. The physicochemical properties including pH, electrical conductivity and texture were determined. Contents of 6 trace metals (Cd, Cr, Cu, Ni, Zn and Pb) were measured using Atomic Absorption Spectrometry method (AAS). <strong></strong></p><p>The results showed that soils of Kenitra city have a sandy texture with a predominance of alkaline pH. The analyzed soil samples can be considered as no salt due to low electrical conductivity values. The trace metals contents revealed that soils are uncontaminated.</p>