DERIVED CROSSED MODULES

Sahan, Tuncar The Kangwon-Kyungki Mathematical Society 2018 한국수학논문집 Vol.26 No.3

In this study, we interpret the notion of homotopy of morphisms in the category of crossed modules in a category C of groups with operations using the categorical equivalence between the categories of crossed modules and of internal categories in C. Further, we characterize the derivations of crossed modules in a category C and obtain new crossed modules using regular derivations of old one.

Antimicrobial effect of PEG–PLA on food-spoilage microorganisms

Yasemin Sahan,Ozan Gurbuz,Gulsen Goncagul,Ali Kara,Cuneyt Ozakin 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.4

Polyethylene glycol (PEG) and polyethylene glycol–polylactic acid (PEG–PLA) have an organic structure and no negative effect on human health. The present study compares the antimicrobial effectiveness of PEG and PEG–PLA on microbial growth. The following pathogens and fungi were examined: seven bacteria strains and 10 fungi (four yeasts and six molds). PEG, a non-modified polymer, exhibited no inhibition effect on all test microorganisms. However, the antimicrobial effect increased with the concentration of PEG–PLA. Bacteria showed more sensitivity to PEG–PLA compared with the other microorganisms used in this study. Enterobacter ATCC 19434 was found to be the most resistant bacteria. Molds and yeasts were more resistant than bacteria against PEG–PLA. MIC and MFC could not be determined on the tested fungi owing to the level of concentrations used, with the exception of the yeast Candida albicans and the molds Penicillium expansum and Aspergillus parasiticus.

Tensor on N(k)-Quasi-Einstein Manifolds

Mallick, Sahanous,De, Uday Chand Department of Mathematics 2016 Kyungpook mathematical journal Vol.56 No.3

The object of the present paper is to study N(k)-quasi-Einstein manifolds. We study an N(k)-quasi-Einstein manifold satisfying the curvature conditions $R({\xi},X){\cdot}Z=0$, $Z(X,{\xi}){\cdot}R=0$, and $P({\xi},X){\cdot}Z=0$, where R, P and Z denote the Riemannian curvature tensor, the projective curvature tensor and Z tensor respectively. Next we prove that the curvature condition $C{\cdot}Z=0$ holds in an N(k)-quasi-Einstein manifold, where C is the conformal curvature tensor. We also study Z-recurrent N(k)-quasi-Einstein manifolds. Finally, we construct an example of an N(k)-quasi-Einstein manifold and mention some physical examples.

Water Pinch Analysis for a Reverse Osmosis Desalination Network to Increase Fresh Water Production

Srinivas Sahan Kolluri,Iman Janghorban Esfahani,ChangKyoo Yoo 대한환경공학회 2013 대한환경공학회 학술발표논문집 Vol.2013 No.6

Effects of oleaster flour supplementation in total phenolic contents, antioxidant capacities and their bioaccessibilities of cookies

Yasemin Sahan,Emine Aydin,Ayse Inkaya Dundar,Dilek Dulger Altiner,Guler Celik,Duygu Gocmen 한국식품과학회 2019 Food Science and Biotechnology Vol.28 No.5

In presented study total phenolic contents, antioxidant capacities and their bioaccessibilities from cookies supplemented with oleaster flour were investigated. Oleaster flours (OFs) were produced using two different methods (peeled oleaster flour: POF and unpeeled oleaster flour: UPOF) from two different genotypes. OFs were used to replace wheat flour in the cookie formulation (control) at the levels of 5, 10, 15, 20 and 25% (w/w). According to the results, enrichment of OFs clearly increased total phenolic contents, antioxidant capacities and bioaccessibilities of cookies. The highest bioaccessible antioxidant capacities (ABTS, CUPRAC, and FRAP) of the samples were obtained from cookie samples enriched with 25% UPOF-1. In conclusion, the increases in phenolic contents, antioxidant capacities, and bioaccessibilities from cookies supplemented with OFs suggest the potential enhancement of beneficial health effect of cookie due to increased content of bioactive compounds present in oleaster flour.

Effect of Processing Techniques on Antioxidative Enzyme Activities, Antioxidant Capacity, Phenolic Compounds, and Fatty Acids of Table Olives

Yasemin Sahan,Asuman Cansev,Hatice Gulen 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.3

In this study, olive fruits (Olea europeae cv. Gemlik) of the most common sources of table olives in Turkey were used. Total polyphenol content (TPC),antioxidant capacity (AC), and antioxidant enzymes (catalase, CAT; ascorbate peroxidase, APX; and glutathione reductase, GR) of table olives were compared by 4different methods of ripe table olive processing. Results revealed that TPC of the processed olives ranged from 117.44 to 418.69 mg gallic acid equivalents/g fresh weight (f.w.). The highest AC as mg Trolox equivalents of 189.58/g f.w. was obtained from unprocessed black olives. CAT,APX, and GR activities of unprocessed olives were higher than those obtained in all processed olives. In conclusion,TPC, AC, and antioxidant enzyme activities are strongly affected by fruit ripening and processing in table olives of ‘Gemlik’ cultivar. In addition, the best processing technique is untreated black olives in brine for antioxidant properties.

Super Quasi-Einstein Manifolds with Applications to General Relativity

Mallick, Sahanous Department of Mathematics 2018 Kyungpook mathematical journal Vol.58 No.2

The object of the present paper is to study super quasi-Einstein manifolds. Some geometric properties of super quasi-Einstein manifolds have been studied. We also discuss $S(QE)_4$ spacetime with space-matter tensor and some properties related to it. Finally, we construct an example of a super quasi-Einstein spacetime.

Evaluation of multivariate statistical analyses for monitoring and prediction of processes in an seawater reverse osmosis desalination plant

Srinivas Sahan Kolluri,Iman Janghorban Esfahani,Prithvi Sai Nadh Garikiparthy,유창규 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.8

Our aim was to analyze, monitor, and predict the outcomes of processes in a full-scale seawater reverse osmosis (SWRO) desalination plant using multivariate statistical techniques. Multivariate analysis of variance (MANOVA) was used to investigate the performance and efficiencies of two SWRO processes, namely, pore controllable fiber filterreverse osmosis (PCF-SWRO) and sand filtration-ultra filtration-reverse osmosis (SF-UF-SWRO). Principal component analysis (PCA) was applied to monitor the two SWRO processes. PCA monitoring revealed that the SF-UF-SWRO process could be analyzed reliably with a low number of outliers and disturbances. Partial least squares (PLS) analysis was then conducted to predict which of the seven input parameters of feed flow rate, PCF/SF-UF filtrate flow rate, temperature of feed water, turbidity feed, pH, reverse osmosis (RO)flow rate, and pressure had a significant effect on the outcome variables of permeate flow rate and concentration. Root mean squared errors (RMSEs) of the PLS models for permeate flow rates were 31.5 and 28.6 for the PCF-SWRO process and SF-UF-SWRO process, respectively, while RMSEs of permeate concentrations were 350.44 and 289.4, respectively. These results indicate that the SF-UF-SWRO process can be modeled more accurately than the PCF-SWRO process, because the RMSE values of permeate flowrate and concentration obtained using a PLS regression model of the SF-UF-SWRO process were lower than those obtained for the PCF-SWRO process.

Transient analysis of cross-ply laminated shells using FSDT: Alternative formulation

Mehmet Fatih Sahan 국제구조공학회 2015 Steel and Composite Structures, An International J Vol.18 No.4

This paper aims to present an alternative analytical method for transient vibration analysis of doubly-curved laminated shells subjected to dynamic loads. In the method proposed, the governing differential equations of laminated shell are derived using the dynamic version of the principle of virtual displacements. The governing equations of first order shear deformation laminated shell are obtained by Navier solution procedure. Time-dependent equations are transformed to the Laplace domain and then Laplace parameter dependent equations are solved numerically. The results obtained in the Laplace domain are transformed to the time domain with the help of modified Durbin's numerical inverse Laplace transform method. Verification of the presented method is carried out by comparing the results with those obtained by Newmark method and ANSYS finite element software. Also effects of number of laminates, different material properties and shell geometries are discussed. The numerical results have proved that the presented procedure is a highly accurate and efficient solution method.

Effects of Cold Stress on Broiler Performance and Ascites Susceptibility

Ipek, A.,Sahan, U. Asian Australasian Association of Animal Productio 2006 Animal Bioscience Vol.19 No.5

The present study was conducted to determine the effect of cold stress on broiler performance and ascites susceptibility. Male chicks were obtained from a commercial strain of broiler breeders. The trial was divided into two treatments (control and cold stress groups). Ascites was induced in broiler chickens in the trial by exposing the chickens to low temperature (Ta) and by supplying a pelleted diet. The two experimental treatments consisted of: 1) Control group, $33.3^{\circ}C$ the $1^{st}$ wk, $30.2^{\circ}C$ the $2^{nd}$ wk, and $27.5^{\circ}C$ the $3^{rd}$ wk. 2) Cold stress group, $29.0^{\circ}C$ the $1^{st}$ wk, $26.4^{\circ}C$ the $2^{nd}$ wk, and $23.1^{\circ}C$ the $3^{rd}$ wk. From the end of the $3^{rd}$ wk all broilers were reared to 6 wk of age at a constant temperature of $21^{\circ}C$. There was significant difference in live BW during wk 1 to 5. The control group was consistently the heaviest; however, at 6 wk of age, both groups weighed the same. Body weight gain up to 3 wk was significantly decreased by cold stress. During wk 3 and 6 the chicks in the cold stress group had greater BW gain compared with the chicks in the control group. There were significant differences in mortality due to ascites between the groups. During wk 3 and 6 the cold stress group exhibited the most ascites mortality (9.52%) when compared with the control group (1.90%). At 5 wk of age cold stress condition caused significant changes in packed cell volume (PCV), hemoglobin (Hb) and red blood cell counts (RBC). Right ventricle weight was significantly heavier in the cold stress group than the control. There were also significant differences in right ventricle/total ventricle (RV/TV) ratios at 5 wk. the right ventricle/total ventricle ratios in the cold stress group was higher (0.25) than the control group (0.20). It was concluded that, fast growth and cold temperatures are the primary triggers for ascites during commercial broiler production.