When the guard honey bees, Apis mellifera L., form a clump at the hive entrance or on the flight board, the oriental hornet, Vespa orientails L., either creeps toward the clump or hovers over it in order to take a bee. Once the hornet creeps, only few bees facing the hornet become alert, rock their heads and antennae, open their wings, and take a posture of defense. The rest of the clump stays listless without any signal of concern. However, the clump stays dense and the defending bees do not detach themselves neither from the rest of the clump nor from each other. For this reason, it is very difficult for the hornet to grab a bee unless the latter makes a “mistake” by detaching herself from other adjacent bees. If the hornet grabs such a bee, the other defending bees will not attack the hornet to free that bee even when the latter is one centimeter from the others. The defending bees can capture the hornet only when the latter grabs one of them which stands very close to the others. The hornet seems very “aware” of such a situation; hence she seldom becomes a captive. On the other hand, hovering over the clump makes it easier for the hornet to grab a bee. The hovering puts all the clump, rather than part of it, on alert. If the hornet is persistent, which is not often the case, then the clump will no longer be dense. The bees will panicly disperse all over the flight board; hence the hornet can find a detached bee and grabs it easily. The hornet also waits on wing in front of the hive to capture an outgoing or incoming flying bee but the latter usually maneuver to escape. Also, foraging bees reduce their activity during main hours of hornet presence. Among the main factors reducing the hornet impact are the continuous chasing of hornets to each other and the non-persistent attempts of the hornets when they attack bee clumps.
This paper presents an experimental and numerical study which was carried out to examine the influence of the size and the layout of the web openings on the load carrying capacity and the serviceability of reinforced concrete deep beams. Five full-scale simply supported reinforced concrete deep beams with two large web openings created in shear regions were tested up to failure. The shear span to overall depth ratio was (1.1). Square openings were located symmetrically relative to the midspan section either at the midpoint or at the interior boundaries of the shear span. Two different side dimensions for the square openings were considered, mainly, (200) mm and (230) mm. The strength results proved that the shear capacity of the dee
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In this study, epoxy was used as a matrix for composite materials, with E-glass fiber, jute and PVC fiber which was woven roving fiber, as reinforcement with volume fraction (Vf= 30%). There are two of prepared types of epoxy non reinforced, epoxy reinforced with E-glass, jute and PVC fibers including study of mechanical tests (Impact test, Bending test) different temperature and thermal conductivity and calculating the temperatures coefficient at different temperature. Results show that elastic modulus at rate values decrease to the increase of temperature and the impact strength, impact energy and thermal conductivity increase with increase temperature.
Abstract
The current research aims to identify the negotiation behavior of administrative teachers, as well as to identify the significance of the differences in negotiation behavior according to the variables (gender, scientific title, length of service). After confirming the psychometric characteristics of (20) items, the researchers applied the scale to (400) male and female administrative teaching staff who were randomly selected from the University of Baghdad for the academic year 2021/2022. The results showed the following the research sample has a negotiating behavior. There are no statistically significant differences between gender, scientific title, and length of service in the means of negotiating beha
... Show MoreComputational study of three-dimensional laminar and turbulent flows around electronic chip (heat source) located on a printed circuit board are presented. Computational field involves the solution of elliptic partial differential equations for conservation of mass, momentum, energy, turbulent energy, and its dissipation rate in finite volume form. The k-ε turbulent model was used with the wall function concept near the walls to treat of turbulence effects. The SIMPLE algorithm was selected in this work. The chip is cooled by an external flow of air. The goals of this investigation are to investigate the heat transfer phenomena of electronic chip located in enclosure and how we arrive to optimum level for cooling of this chip. These par
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Polymer electrolytes were prepared using the solution cast technology. Under some conditions, the electrolyte content of polymers was analyzed in constant percent of PVA/PVP (50:50), ethylene carbonate (EC), and propylene carbonate (PC) (1:1) with different proportions of potassium iodide (KI) (10, 20, 30, 40, 50 wt%) and iodine (I2) = 10 wt% of salt. Fourier Transmission Infrared (FTIR) studies confirmed the complex formation of polymer blends. Electrical conductivity was calculated with an impedance analyzer in the frequency range 50 Hz–1MHz and in the temperature range 293–343 K. The highest electrical conductivity value of 5.3 × 10-3 (S/cm) was observed for electrolytes with 50 wt% KI concentration at room
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The first molecular research on Iraqi centipede fauna is presented in this article. Between October 2022 and May 2023, during various climatic circumstances, centipedes were collected from several locations in four provinces of Iraq. Three families, represented by four genera, underwent molecular identification, and five species were found. From the order Scolopendromorpha family Scolopendridae, two species were recorded, Scolopendra morsitans Linnaeus, 1758, and S. cingulata Latreille, 1829, Cormocephalus sp.; while from the order Lithobiomorpha, family Lithobiidae, one species was recorded for first time in Iraq; Lithobius crassipes L. Koch, 1862 from the order Geophilomorpha family Himantariidae, one species Bothriogaster Signata
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A study was carried out in the vineyard at Al- sowayra in the Waset Province to study the effect of boron spray on cluster and fruits traits characteristics of grape cultivar . Borax used was as a source of boron at the concentrations (0.0 , 0.1, 0.2, 0.3, 0.4 and 0.5 ) g / l . Water plus Wetting agent (0.05 g/l detergent) was sprayed to induce faom and reduce water surface tension. The spray was implemented twice, first was one week before blooming and the second was after fruit set. Results showed that spray treatment by boron increased. weight and volume of berries and increased cluster's weight bunch length and diameter besides the increased number of Fruits in bunch also Total Soluble Solids (Tss%) was increased wh
... Show MoreThe anthocyanin navonoid pigment isolated from lrdqi red radish peels (Raphanus Sativus L) was used as an acid - base indicator
with a pk equal 7.0 and pH equal (6-8). TI1e acidic water extract was successfully used instead of conventional litmus papers.
This study aims at examining and confirming the patterns of phenetic relationships and the levels of variations within and among the species of Lotus L., 1753 in Egypt by using morphometric analysis techniques. We have evaluated 24 morphological characters from about 300 herbarium specimens representing 19 species of Lotus that are currently recognized. Based on numerical analyses of macromorphological characters (cluster analysis, principal coordinate analysis and principal component analysis), 19 species of Lotus were recognized from Egypt. These species were clustered in six species-specific groups: (I) Lotus halophilus Boiss. & Spruner, L. angustissimus L., L. glinoides Delile and L. schimperi Steud. ex Boiss., (II) Lotus glaber
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