Liaison of phenolic acids and biological activity of escalating cultivars of Daucus carota

The objective of the present study was to analyze and compare the phenolic compounds and their antioxidant capacities of new lines of Dacus carota. The selected cultivars showed high variation in the contents of total phenolics (30.26–65.39 mg/100 g FW) and total ascorbic acid (41.12–58.36 mg/100 g FW). Analysis on RP-HPLC revealed that hydroxycinnamic acids and its derivatives were major phenolic compounds present in D. carota extracts, whereas 5-caffeolquinic acid was a major hydroxycinnamic acid (ranged from 30.26 to 65.39 mg/100 g FW). DCP cultivar showed high total antioxidant capacity (77.69 mg/100 g), 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity (52.36 mg/100 g), superoxide radical scavenging capacity (53.69 mg/100 g), and hydroxyl radical scavenging capacity (51.91 mg/100 g). A linear relationship was found between total phenolic acid contents and antioxidant capacity. Both phenolic compounds and antioxidant capacities varied significantly (ρ < 0.05) among cultivars. DCP cultivar was found to be a rich source of phenolics and ascorbic acid with high antioxidant activity.     

Melt Production and Antimicrobial Efficiency of Low-Density Polyethylene (LDPE)-Silver Nanocomposite Film

Colloidal silver nanoparticles with a size of 5.5 ± 1.1 nm were prepared by chemical reduction using polyethylene glycol (PEG). Silver nanoparticles were incorporated into low-density polyethylene (LDPE) by melt blending and subsequent hot pressing at 140 °C to produce nanocomposite film with an average thickness of 0.7 mm. PEG was added at 5% weight of polymer as a compatibilizer agent in order to prevent agglomeration and provide uniform distribution of nanoparticles in polymer matrix. Antimicrobial activity of silver nanocomposites against Escherichia coli ATCC 13706, Staphylococcus aureus ATCC12600, and Candida albicans ATCC10231 was evaluated by semi-qualitative agar diffusion test and quantitative dynamic shake flask test. Mechanical properties of nanocomposites were not significantly different from silver-free LDPE-containing PEG films (p > 0.05), and silver nanoparticles did not form chemical bonding with the polymer. LDPE-silver nanocomposite samples by more than 6.69 ppm silver nanoparticles showed considerable antimicrobial clear zone. LDPE-silver nanocomposite affected growth kinetic parameters of the examined bacteria and is more efficient on S. aureus than E. coli. Polyethylene-silver nanocomposites containing 22.64 ppm silver nanoparticles could reduce 57.8% growth rate and 23.3% maximum bacterial concentration and increase 35.8% lag time of S. aureus. This study shows the potential use of LDPE-silver nanocomposite as antimicrobial active film. Antimicrobial efficiency of silver nanocomposite depends on silver nanoparticles concentration; however, high level of silver nanoparticles may lead to weakening of mechanical properties.     

The effect of heat treatments on the properties of Ti/Pt heating elements for gas sensor applications

Ti/Pt as heating element for gas sensor applications was fabricated on silicon (Si) wafer substrate. The fabricated device was subjected to heat treatment at different prescribed time periods for thermal stability. The energy dispersion spectroscopy (EDS) results of the device indicated that there were no Ti traces on the Pt surface after heat treatment at 450 °C for 3 and 4 h in an argon (Ar) atmosphere. A maximum temperature coefficient of resistance (TCR) with a value of 2.88×10^?3 K^?1 was obtained for the device with 3 h heat treatment.     

Application of myrrh extract as an eco-friendly dye and antimicrobial agent on wool and silk fabrics part 2: antimicrobial activity and fastness property

ABSTRACT

We investigate the dyeing and antimicrobial properties of myrrh (Commiphora molmol) extracts on wool and silk fabrics, the use of eco-friendly materials such as sumac (Rhus coriaria), manjakani (Quercus infectoria), alum, and ferrous sulfate as mordants. The mordanting methods were optimized.

The best conditions of dyeing process were discussed in the first part of this study. Dyed fabrics were assessed for color strength (K/S), color fastness, and antimicrobial activity. Non-mordanted dyed wool and silk showed color fastness of grade 4–5. Dyed fabrics showed good antimicrobial activity, which was enhanced by mordanting.     

Κ‐CN gene polymorphism in Nili‐ravi buffalo,Achai and Sahiwal cattle of Pakistan

Kappa‐casein (κ‐CN) is the subtype of casein protein, an important constituent of bovine milk protein. The current study was undertaken to investigate the genetic polymorphism in κ‐CN gene of Nili‐ravi buffalo, Achai and Sahiwal cattle of Pakistan using polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) technique. The Nili‐ravi buffalo was found to be monomorphic (genotype BB only) for κ‐CN gene. Achai cattle were polymorphic for κ‐CN (having three genotypes AA, AB and BB) with a frequency of 0.70, 0.18 and 0.12, respectively, while in Sahiwal cattle, both the genotypes AA and AB were found with genotypic frequencies of 0.92 and 0.08, respectively. The presence of genotype BB in Achai cattle is surprising as it is absent in most of the cattle breeds worldwide.     

Unglazed Fiberglass Reinforced Polyester Solar Water Heater with Integrated Storage System

Theoretical and experimental investigations on an unglazed solar hot water heater with integrated storage system were conducted. The system was comprised of a collector and storage tank which was integrated into one unit. All parts of the system have been fabricated from fiberglass reinforced polyester (GFRP). The absorber plate has water tubes of semielliptical shape. The width and length of the absorber plate were 1.4 and 1.8?m, respectively. The absorber plate was fabricated from GFPR using a special resin composition that provides good thermal conductivity and absorptivity. The storage tank has a capacity of 496?L. The storage tank is of sandwich construction with a core material made of polyurethane foam that combines stiffness and lightness of the structure with very good thermal insulation properties. An average tank temperature of 53°C was achieved at an average solar radiation level of 700?W/m2 and ambient temperature of 28°C. The thermal efficiencies of the system were evaluated at 48 and 57% for cloudy and clear days, respectively. Transient performance of the system was predicted by solving the mathematical models consisting of energy balance equations of the system that have been converted to finite difference form and solved by a personal computer. The experimental results were in close agreement as has been found with the theoretical predictions.     

Erratum to: Conductivity Sensors Based System Development and Application to Investigate the Interfacial Behaviour between Supersonic Steam Jet and Water

Instruments and Experimental Techniques - An Erratum to this paper has been published: https://doi.org/10.1134/S0020441221050249     

Amido-Amine-Based Cationic Gemini Surfactants: Thermal and Interfacial Properties and Interactions with Cationic Polyacrylamide

Experimental studies were conducted to investigate thermal and interfacial properties of two in‐house synthesized amido‐amine‐based cationic gemini surfactants namely: dodecanoic acid [3‐({4‐[(3‐dodecanoylamino‐propyl)‐dimethyl‐amino]‐butyl}‐dimethyl‐amino)‐propyl]‐amide dibromide ( 12‐4‐12 ) and dodecanoic acid [3‐({6‐[(3‐dodecanoylamino‐propyl)‐dimethyl‐amino]‐hexyl}‐dimethyl‐amino)‐propyl]‐amide dibromide ( 12‐6‐12 ). Thermogravimetric analysis showed the excellent thermal stability of surfactants and no structural degradation was observed at temperatures up to 250 °C. The long‐term thermal stability of the surfactants was investigated with the aid of spectroscopic techniques such as nuclear magnetic resonance (NMR (¹H and ¹³C) and Fourier transform infrared (FTIR) spectroscopy. Both surfactants were found to be thermally stable, and no changes in structure were observed after aging for 10 days at 90 °C. The interfacial tension of the surfactants was measured at three different temperatures (30, 60, and 80 °C), and the results showed a decrease in interfacial tension with increasing temperature and increasing spacer length of the surfactants. Rheological measurements were used to assess the interactions between the cationic gemini surfactant and cationic polyacrylamide. The addition of cationic surfactant reduced the viscosity and storage modulus of the polymer at low shear rate and frequency due to surfactant–polymer interactions and charge screening. The investigated surfactant–polymer system has great potential in high‐temperature carbonate reservoirs, where conventional anionic surfactants are not recommended due to high adsorption.     

Modification of sandy soil using water‐borne polymer

A new polymeric system has been applied for structural modification of (noncompactable) sandy soils. The system is based on a water‐borne styrene acrylic polymeric formulation (emulsion) containing varying amounts of solid polymer. The present work deals with system optimization and measurements designed to examine the effects of polymer content on hydraulic conductivity and compressive strength. Samples were prepared from prescribed amounts of polymer, water, and sand by using two different preparations methods (mixing and spraying). Measurements of hydraulic conductivity for both sets of samples were conducted in a flexible membrane test apparatus. For the first set of samples, the permeability coefficient of the sand was noted to be reduced 10‐fold (from 10^?5 to 10^?6 m s^?1) upon the incorporation of about 2% polymer. In the second set (samples prepared with the spraying method), the hydraulic conductivity was further reduced to 7.2 × 10^?7 at a polymer concentration of about 2%. Stress–strain measurements made on dry cylindrical specimens disclosed remarkable enhancement in the mechanical behavior of the system. For both types of preparation methods, the compressive strength and modulus of elasticity increased linearly with the polymer concentration in the sample. Scanning electron microscopic examination revealed that the dramatic reduction in the permeability and the improved mechanical properties are attributed to the polymer coverage of the sand particles and the development of interconnecting ties between them. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 2484–2491, 2003     

Kinetic study of crude oil-to-chemicals via steam-enhanced catalytic cracking in a fixed-bed reactor

This study presents new experimental results on the direct conversion of crude oil to chemicals via steam-enhanced catalytic cracking. We have organized the experimental results with a kinetics model using crude oil and steam co-feed in a fixed-bed flow reactor at reaction temperatures of 625, 650, and 675°C over the Ce-Fe/ZSM-5 catalyst. The model let us find optimum conditions for crude oil conversion, and the order of the steam cracking reaction was 2.0 for heavy oil fractions and 1.0 for light oil fractions. The estimated activation energies for the steam cracking reactions ranged between 20 and 200 kJ/mol. Interestingly, the results from kinetic modelling helped in identifying a maximum yield of light olefins at an optimized residence time in the reactor at each temperature level. An equal propylene and ethylene yield was observed between 650 and 670°C, indicating a transition from dominating catalytic cracking at a lower temperature to a dominating thermal cracking at a higher temperature. The results illustrate that steam-enhanced catalytic cracking can be utilized to effectively convert crude oil into basic chemicals (52.1% C2-C4 light olefins and naphtha) at a moderate severity (650°C) as compared to the conventional high-temperature steam cracking process.