Impact of load profile and collector technology on the fractional savings of solar domestic water heaters under various climatic conditions

This paper investigates the influence of the domestic hot water load profiles and the collector's technology (Flat Plate FPC, Evacuated Tube ETC and Compound Parabolic CPC) on the performance of forced circulation solar water heaters operating under various climatic conditions. For this end, a typical single family house composed of five occupants located in Morocco was considered. It is found that, the solar fraction can reach annual average values of 80% especially in areas with high solar energy potential. For a fixed consumption profile, the simulations showed that the installations with FPC, ETC and CPC can consume about 1644, 1199 and 1481 kWh/year of auxiliary energy, respectively. Moreover, it is found that, adapting the consumption profile, can save approximately 43 kWh/year for FPC, 13 kWh/year for ETC and about 29 kWh/year for CPC of energy.     

Assessment of antioxidant activity and phycocyanin release of Spirulina loaded poly(ε-caprolactone) electrospun nanofibers

PCL with biodegradable property and Spirulina with various biological activities offer good alternative ingredients for the fabrication of functional nanofibers in tissue engineering. The aim of the study is to obtain PCL/Spirulina nanofibers with low diameters and to determine their wettability, antioxidant activity, and phycocyanin release to evaluate their potential as bioactive scaffolds in different applications. PCL/acetic acid/pyridine solutions with three different Spirulina concentrations were electrospun and the obtained nanofibers were investigated. The thinnest PCL/Spirulina nanofibers (117.20 nm) were obtained at 1.5% Spirulina concentration. Although PCL nanofibers with 6% Spirulina concentration showed the highest antioxidant activity and amount of phycocyanin released, PCL nanofibers with 3% Spirulina concentration having similar in vitro results showed superiority when considering the diameter and uniformity of the nanofibers and the cost of the material. The PCL/Spirulina nanofibers with small diameters and antioxidant activity could be regarded as potential extracellular matrix material for tissue engineering.     

Changes in free amino acids and biogenic amines of Egyptian salted-fermented fish (Feseekh) during ripening and storage

The aim of this study was to investigate changes in the formation of amino acids and biogenic amines in Egyptian salted-fermented fish (Feseekh) during ripening (20 days) and storage (40–60 days). The total concentration of free amino acids increased from 8 (dry weight; DW) to 72 g/kg (DW) after 60 days of storage. The predominant free amino acids were leucine, glutamic acid, lysine, alanine, valine, aspartic acid, isoleucine and citrulline. Their concentrations accounted for 68% of the total concentration of amino acids after 60 days. The total contents of biogenic amines ranged from 84 to 1633 mg/kg (DW) during the investigated period. Cadaverine was the major amine detected in Feseekh at all sampling stages and its concentration varied between 21 and 997 mg/kg (DW). The histamine content (211 mg/kg DW) only exceeded the maximum tolerance level (200 mg/kg) after 60 days. It could be concluded that Feseekh can be consumed without any health risks between 20 and 40 days but it can be hazardous after 60 days due to the biogenic amine content.     

A committee machine with intelligent systems for estimation of total organic carbon content from petrophysical data: An example from Kangan and Dalan reservoirs in South Pars Gas Field,Iran

Total organic carbon (TOC) content present in reservoir rocks is one of the important parameters, which could be used for evaluation of residual production potential and geochemical characterization of hydrocarbon-bearing units. In general, organic-rich rocks are characterized by higher porosity, higher sonic transit time, lower density, higher γ-ray, and higher resistivity than other rocks. Current study suggests an improved and optimal model for TOC estimation by integration of intelligent systems and the concept of committee machine with an example from Kangan and Dalan Formations, in South Pars Gas Field, Iran. This committee machine with intelligent systems (CMIS) combines the results of TOC predicted from intelligent systems including fuzzy logic (FL), neuro-fuzzy (NF), and neural network (NN), each of them has a weight factor showing its contribution in overall prediction. The optimal combination of weights is derived by a genetic algorithm (GA). This method is illustrated using a case study. One hundred twenty-four data points including petrophysical data and measured TOC from three wells of South Pars Gas Field were divided into 87 training sets to build the CMIS model and 37 testing sets to evaluate the reliability of the developed model. The results show that the CMIS performs better than any one of the individual intelligent systems acting alone for predicting TOC.     

Garlic peroxidase immobilized into chitosan matrix suitable for biosensors applications

Peroxidase X₁ (POX₁) isoenzyme was purified from garlic bulb (Allium sativum L.). Native-PAGE profile showed two isoforms partially purified (designated POX_1A and POX_1B). A POX_1B-based electrode showed great potential for monitoring hydrogen peroxide in biological samples. Chitosan was used as a matrix for enzyme immobilization. The enzyme activities were studied by photometry. Immobilization was accomplished by either inclusion in a thin film or adsorption to cross-linked microspheres. Two linkage agents were used: glutaraldehyde and glyoxal. The best immobilization and activity yields (82%, 95%) were obtained when POX_1B was incorporated within a chitosan/glyoxal film. The effect of temperature on the immobilized enzyme was tested. Results showed that full activity was retained after 40 min incubation at 40 °C. Anchored POX_1B inside chitosan was used for biosensor design. Cyclic voltammetry and impedance spectroscopy were employed to analyze electrochemical properties of the modified gold electrode and to monitor hydrogen peroxide. The biosensor was very sensitive and attained a detection limit of 100 nM.     

The synthesis and photophysicochemical behaviour of novel water-soluble cationic indium(III) phthalocyanine

The syntheses and characterization of 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) and quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) are described. The ground state electronic absorption spectra, photophysics and photochemistry of both dyes in DMSO as well as that of the quaternized compound in aqueous solution are also presented. A comparison of the photophysical and photochemical parameters of the two dyes revealed that quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) was a better photosensitizer than its unquaternized counterpart. The quantum yield values of fluorescence (Φ_F), triplet state formation (Φ_T) and singlet oxygen formation (Φ_Δ) for the cationic dye were found to be 0.03, 0.68 and 0.66 respectively in DMSO; these values were higher than those for 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III), which exhibited values of 0.02, 0.66 and 0.63, respectively in DMSO. The values for the cationic dye in aq. solution were 0.02, 0.59 and 0.56 respectively, suggesting that the water-soluble quaternized 2,3-octakis-(3-pyridyloxyphthalocyaninato) indium(III) offers potential as a photosensitizer in photodynamic therapy treatment.     

Sustainability of Groundwater Resources in the North-Eastern Region of Bangladesh

Water is essential for economic, social, and environmental development. Global water resources are vulnerable due to increasing demand related to population growth, pollution potential, and climate change. Competition for water between different sectors is increasing. To meet the increasing demand, the use of groundwater is increasing worldwide. In this paper, the water-table dynamics of the north-eastern region of Bangladesh were studied using the MEKESENS software. This study reveals that the depth to water-table (WT) of almost all the wells is declining slowly. In many cases, the depth will approximately double by the year 2040, and almost all will double by 2060, if the present trend continues. If the decline of the water-table is allowed to continue in the long run, the result could be a serious threat to the ecology and to the sustainability of food production, which is vital for the nation’s food security. Therefore, necessary measures should be taken to sustain water resources and thereby agricultural production. Demand-side management of water and the development of alternative surface water sources seem to be viable strategies for the area. These strategies could be employed to reduce pressure on groundwater and thus maintain the sustainability of the resource.     

Mathematics for reasoning about loop functions

The criticality of modern software applications, the pervasiveness of malicious code concerns, the emergence of third-party software development, and the preponderance of program inspection as a quality assurance method all place a great premium on the ability to analyze programs and derive their function in all circumstances of use and all its functional detail. For C-like programming languages, one of the most challenging tasks in this endeavor is the derivation of loop functions. In this paper, we outline the premises of our approach to this problem, present some mathematical results, and discuss how these results can be used as a basis for building an automated tool that derives the function of while loops under some conditions.     

Electropolymerization and characterization of polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol)

Applications of conducting polymers to biosensors have recently aroused much interest. This is because these molecular electronic materials offer control of different parameters such as polymer layer thickness, electrical properties and bio-reagent loading, diversity, ease of fabrication and potentially low cost, etc. Polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol) preparations are performed with electrochemical (CV) method at room temperature, in a standard three-electrode cell. Homopolymer and the copolymers of aniline and 2-anilinoethanol films were deposited from 1?M acidic aqueous media containing 0.2?M aniline, 2-anilinoethanol by voltammetric sweep between ?0.1 and 1 V Ag/AgCl, at 20?mV/s^?1. The sweep was stopped after 30 cycles at ?0.1?V Ag/AgCl and the working electrode was covered by homopolymer and copolymer of aniline and 2-anilinoethanol. Characterizations of the products were carried out by cyclic voltammograms, UV?Cvisible, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance (EIS) was employed to examine the water absorption of the synthesized polymers to be used in biosensor application. Electrochemical properties of polyaniline, poly(2-anilinoethanol) and poly(aniline-co-2-anilinoethanol) were studied and it is shown that with increased (2-anilinoethanol) content in the copolymer, its electroactivity, conductivity and resistance are reduced, though the processability and adhesion properties improve. The hydrophilicity of polymer film obtained has increased with increasing (2-anilinoethanol) content which leads to salt moving to the surface of steel.