Modulus of elasticity of substandard and normal concretes

Modulus of elasticity is an important parameter used for the structural assessment and retrofitting of concrete structures. In this study, an experimental investigation on the modulus of elasticity of concrete was carried out, the results of which is presented. 60 mixtures were prepared, in which the effects of water/cement ratio, maximum size of the aggregate, aggregate type, and fly ash content were investigated. In order to obtain very low quality concrete, the water/cement ratios were increased to as high as 2.2. Modulus of elasticity of the concretes was obtained according to ASTM C469. Compressive strength and ultrasound pulse velocities of the concretes were also recorded. The experimentally obtained modulus of elasticity values were compared with those calculated by using prediction models given in a selection of codes of practice. Dynamic moduli of elasticity of the concretes were also obtained.     

A production insensitive compact power divider

Power dividers are inevitable components in most microwave systems. Well known topologies like Wilkinson power divider are widely studied in the literature. An “all 50 ohm power divider” is another topology presented in the some works. In this study, an all 50 ohm structure is taken as the basis and a compact-easy to implement modification the power divider is proposed. A sample structure is designed, implemented and measured to prove the topology. The decreased sensitivity to production tolerances is demonstrated by various design modifications. Comparisons with well-known topologies are given for reference.     

Identification of phenolic profiles,fatty acid compositions,antioxidant activities,and enzyme inhibition effects of seven wheat cultivars grown in Turkey: A phytochemical approach for their nutritional value

In the present article, seven wheat cultivars (Ahmetaga, Bezostaya, Dagdas-94, Ekiz, Karahan-99, Konya-2002, and Tosunbey) grown in Turkey were compared for their phytochemical composition, antioxidant, and enzyme inhibitory activities. Antioxidant capacities and enzyme inhibitory effects were investigated with colorimetric methods. Total phenolic content ranged from 40.71 to 86.34 mg of gallic acid equivalent/100 g wheat grain. Tosunbey (92 mg Trolox equivalent/100 g wheat grain) and Ahmetaga (114.56 mg Trolox equivalent/100 g wheat grain) cultivars exhibited strong 2,2 azino-bis (3-ethylbenzothiazloine-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activities. As compared to other wheat cultivars, Tosunbey cultivar had remarkable both antioxidant and enzyme inhibitory effects with the highest level of phenolics. Ferulic acid, chlorogenic acid, and apigenin were the major phenolics in extracts tested. This study suggested that an increased intake of wheat derived products could represent an effective strategy for the management of oxidative stress related chronic and degenerative diseases such as Alzheimers and diabetes mellitus.     

Microbiological and Chemical Properties of Cheese Helva Produced in Turkey

In this study, the microbiological and chemical properties of Cheese helva, one of the traditional cheeses varieties produced in Turkey, was studied. This cheese is called Cheese helva since it is produced from wheat flour and milk cream. Samples were randomly collected from different villages in the Erzurum province of Turkey. The average of total aerobic mesophilic bacteria (TAMB), yeast and mould, yeast, lactic acid bacteria (LAB), proteolytic bacteria, and lipolytic bacteria were determined 4.9 × 10⁷, 6.4 × 10⁴, 3.5 × 10³, 7.6 × 10⁶, 4.6 × 10³, and 8.6 × 10³ cfu/g, respectively. 44.44% of the Cheese helva samples had no coliform; the samples that were positive for coliform showed an average of 5.1 × 10³ cfu/g. Staphylococcus aureus was found < 10 cfu/g in analyzed samples. The Cheese helva was characterized by dry matter as 84.32 kg/100 kg cheese, fat as 37.44 kg/100 kg cheese, protein as 13.75 kg/100 kg cheese, NaCI as 0.58 kg/100 kg cheese, titratable acidity as 0.210%, pH as 5.30, ash as 1.49 kg/100 kg cheese, and carbohydrate as 38.56 kg/100 kg cheese. Cheese helva was found to have a high variation based on chemical composition. The microbiological tests revealed that there were high amounts of total bacteria, yeast and molds, molds, lactic acid bacteria, lipolytic bacteria, proteolytic bacteria, and coliforms.     

Screening of Possible In Vitro Neuroprotective,Skin Care,Antihyperglycemic, and Antioxidative Effects of Anchusa undulata L. subsp. hybrida (Ten.) Coutinho from Turkey and Its Fatty Acid Profile

The aim of this work was to determine antioxidant capacities, neuroprotective, skin care, antidiabetic effects, and fatty acid composition of Anchusa undulata subsp. hybrida. The antioxidant activity was screened by four different test systems including total antioxidant, antiradical, reducing power, and metal chelating activities. Neuroprotective potential was determined by anticholinesterase inhibitor assay. Tyrosinase inhibitory activity was tested to detect skin care effect. Antidiabetic effects were evaluated with α-amylase and α-glucosidase inhibitory assays. Inhibitory activities on acetycholinesterase, butyrylcholinesterase, tyrosinase, α-amylase, and α-glucosidase enzymes were observed as 2.238 and 1.239 μmol GALAEs/g, 0.339 mmol KAEs/g, 0.193, and 0.219 mmol ACEs/g extract, respectively. Amount of total phenolics and flavonoids were found as 80.34 μg GAEs/mg and 25.09 μg QEs/mg in the extract, respectively. Twenty-three fatty acids were found in the aerial parts, being oleic acid (24.30 g/100 g of total fatty acids) the most abundant, followed by linoleic (21.19 g/100 g of total fatty acids) and palmitic acids (17.50 g/100 g of total fatty acids).     

A reversible data hiding scheme based on graph neighbourhood degree

Abstract

The perceptibility and capacity are two vital criteria of data hiding scheme. Concerning these criteria, data hiding algorithm used images as cover object based on the graph theory is proposed in this study. Images are quantised according to determined range and then quantised images are divided into n × n sized blocks. Each block is accepted as a graph and vertexes which have the same quantisation value are accepted as neighbours. Neighbourhood degrees of vertexes are calculated and indices of vertexes that have a neighbourhood degree over the threshold value are stored in the codebook. Pixel values indicated by these indices in the codebook are used for data hiding process. In this algorithm, there is no need for edge extraction because of hiding data to pixels containing vertexes having high neighbourhood degrees. The proposed method is compared with similar methods in literature in terms of the perceptibility and capacity. More successful results are provided than the others.     

Backpressure scheduling in IEEE 802.11 wireless mesh networks: Gap between theory and practice

Achieving efficient bandwidth utilization in wireless networks requires solving two important problems: (1) which packets to send (i.e., packet scheduling) and (2) which links to concurrently activate (i.e., link scheduling). To address these scheduling problems, many algorithms have been proposed and their throughput optimality and stability are proven in theory. One of the most well-known scheduling algorithms is backpressure scheduling which performs both link and packet scheduling assuming a TDMA (Time Division Multiple Access) MAC (Medium Access Control) layer. However, there has been limited work on realizing backpressure scheduling with a CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) MAC layer (e.g., IEEE 802.11). In IEEE 802.11 networks, it is expected that the throughput optimality will not be achieved. In this paper, we investigate the extent of this throughput gap between theoretical TDMA-based backpressure scheduling and an approximation of it for IEEE 802.11 WMNs (Wireless Mesh Networks). Through extensive testbed measurements, we verify that there is indeed a non-negligible throughput gap. We present two main reasons behind this gap: Control inaccuracy that results from approximation of link scheduling and information inaccuracy that results from late or incorrect information, for instance, about queue lengths or network topology. Our results show that losses by MAC-layer collisions and backoff, which mainly occur due to control inaccuracy plays a major role for the throughput gap. On the other hand, while losses by queue drops, typically due to information inaccuracy, do occur, their effect can be tolerated. Nevertheless, both types of inaccuracies need to be mitigated in order to improve throughput.