The effects of augmented reality on students' academic achievement and motivation in a biology course

This study aimed to investigate the effects of augmented reality (AR) activities on students' academic achievement and motivation in a biology course. For this purpose, a mixed study was conducted, and a pretest and posttest control group model was used. In addition, the opinions of the experimental group students and the teacher about the AR activities were taken, and classroom observations were made during the study. The study group consisted of 40 (22 female and 18 male) ninth‐grade biology course students. The control group followed the biology course programme, whereas the experimental group students conducted AR activities in addition to the course programme using tablets. Consequently, it was found that the motivation of the students in the experimental group increased more than that of the students in the control group. However, no significant difference was found between the academic achievement scores of the groups. The teacher and the students stated that AR activities might be effective in increasing course success and motivation.     

Target Capturing in an Ellipsoidal Region for a Swarm of Double Integrator Agents

In this paper we focus on the target capturing problem for a swarm of agents modelled as double integrators in any finite space dimension. Each agent knows the relative position of the target and has only an estimation of its velocity and acceleration. Given that the estimation errors are bounded by some known values, it is possible to design a control law that ensures that agents enter a user-defined ellipsoidal ring around the moving target. Agents know the relative position of the other members whose distance is smaller than a common detection radius. Finally, in the case of no uncertainty about target data and homogeneous agents, we show how the swarm can reach a static configuration around the moving target. Some simulations are reported to show the effectiveness of the proposed strategy.      

Stability of a one-dimensional discrete-time asynchronous swarm.

In this correspondence, we consider a discrete time one-dimensional asynchronous swarm. First, we describe the mathematical model for motions of the swarm members. Then, we analyze the stability properties of that model. The stability concept that we consider, which matches exactly with stability of equilibria in control theory, characterizes stability of a particular position (relative arrangement) of the swarm members. We call that position the comfortable position (with comfortable intermember distances). Our swarm model and stability analysis are different from other asynchronous swarm models considered in the literature. In particular, in our analysis we employ results on contractive mappings from the parallel and distributed computation literature. The application of these results to the swarm coordination problem is important by itself since they might prove useful also in n-dimensional swarms.     

Axial Load-Bending Moment Diagrams of Carbon FRP Wrapped Hollow Core Reinforced Concrete Columns

Hollow core reinforced concrete columns are generally preferred in use to decrease the cost and weight/stiffnesss ratio of members, such as bridge columns and piles. With a simplified stress state assumption, strengthening a hollow core reinforced concrete column with fiber-reinforced polymer (FRP) wrapping provides a biaxial confinement to the concrete, which leads to a need of defining the effect of FRP wrapping on the strength and ductility of the hollow core reinforced concrete columns. In this study, two groups of four hollow core reinforced concrete columns (205?mm outer diameter, 56?mm hollow core diameter, and 925?mm height) were tested under concentric, eccentric (25 and 50?mm eccentricity) and bending loads to observe the effect of carbon FRP (CFRP) wrapping. All the columns had internal steel reinforcement. Half of the columns had three layers of circumferential CFRP wrapping, whereas the other half had no external confinement. Axial load-bending moment (P–M) diagrams of each group were drawn using the obtained experimental results for both groups. It was observed that, CFRP wrapped columns had higher load and moment carrying capacities than the other group. An analytical model is proposed for drawing the P–M diagram of CFRP wrapped hollow core reinforced concrete columns.     

The experimental investigation of heat transfer and pressure drop in a tube with coiled wire inserts placed separately from the tube wall

The paper presents the experimental investigation of heat transfer and pressure drop in a tube with coiled wire inserts placed separately from the tube wall in turbulent flow regime. The experiments were performed with a constant wire thickness of a = 6 mm, three different pitch ratios (P/D = 1, P/D = 2 and P/D = 3) and two different distances (s = 1 mm, s = 2 mm) at which the coiled wire inserts were placed separately from the tube wall. Uniform heat flux was applied to the external surface of the tube and Reynolds numbers varied from 4105 to 26 400 in the experiments. The experimental results obtained from a smooth tube were compared with those from the studies in literature for validation of experimental set up. The use of coiled wire inserts leads to a considerable increase in heat transfer and pressure drop over the smooth tube. The Nusselt number and friction factor increase with decreasing pitch ratio (P/D) and distance (s) for coiled wire inserts. The highest overall enhancement efficiency of 50% was achieved for the coiled wire with P/D = 1 and s = 1 mm at Reynolds number of 4220. As a result, the experimental results reveal that using these coiled wire inserts are thermodynamically advantageous at all Reynolds numbers.     

Comparison of Recurrent Neural Network,Adaptive Neuro-Fuzzy Inference System and Stochastic Models in Eğirdir Lake Level Forecasting

Accurate prediction of lake-level changes is a very important problem for a wise and sustainable use. In recent years significant lake level fluctuations have occurred and can be related to the climatic change. Such a problem is crucial to the works and decisions related to the water resources and management. This study is aimed to predict future lake levels during hydrometeorological changes and anthropogenic activities taking place in the Lake Eğirdir which is the most important water storage of Lake Region, one of the biggest fresh water lakes of Turkey. For this aim, recurrent neural network (RNN), adaptive network-based fuzzy inference system (ANFIS) as prediction models which have various input structures were constructed and the best fit model was investigated. Also, the classical stochastic models, auto-regressive (AR) and auto-regressive moving average (ARMA) models are generated and compared with RNN and ANFIS models. The performances of the models are examined with the form of numerical and graphical comparisons in addition to some statistic efficiency criteria. The results indicated that the RNN and ANFIS can be applied successfully and provide high accuracy and reliability for lake-level changes than the AR and the ARMA models. Also it was shown that these stochastic models can be used in the lake management policies with the acceptable risk.     

Metal(II) Nicotinamide Complexes Containing Succinato,Succinate and Succinic Acid: Synthesis,Crystal Structures,Magnetic, Thermal,Antimicrobial and Fluorescent Properties

Four novel divalent transitional metal succinates (suc) with nicotinamide (nia), {[M(μ-suc)(H₂O)₂(nia)₂]·2H₂O} _n [M = Mn (1), Ni (2)], [Cu(suc)(nia)₂] (3) and [Ni(H₂O)₄(nia)₂](suc)·(H₂suc) (4), have been synthesized and characterized by elemental analyses, IR and TG-DTA. X-ray analyses of 2 and 4 reveal that they crystallize in a triclinic space group P[`1]. P\bar{1}. Complex 2 is a 1-D coordination polymer, in which the metal(II) ions exhibit an octahedral geometry with two suc, two nia and two aqua ligands. The nia ligand is N-bonded, while the suc ligand bridges the metal centres through the carboxylate groups. 4 contains the [Ni(H₂O)₄(nia)₂]²⁺ complex cations, uncoordinated suc and H₂suc species, which are connected into a two-dimensional layered structure by the combination of N–H⋯O and OW–H⋯O hydrogen bonds. This is one of the scarce examples encountered in coordination chemistry, which contains uncoordinated suc and H₂suc at the same time. The spectroscopic and structural analysis, luminescent and magnetic properties and the antimicrobial activities of the synthesized complexes were investigated.     

Evaluation of the integral quantities for incident fusion source neutrons in infinite medium

Integral neutronic quantities have been evaluated for incident 14.1 MeV (D,T) and 2.45 MeV (D,D) fusion source neutrons in infinite medium for the most important materials in fusion technology, namely lithium, beryllium, lead and thorium. The study covers the calculation of the integral tritium breeding ratio, the ²³³U breeding rate (when applicable), the neutron multiplication ratio through (n,x)-and fission-(when applicable) reactions, and the heat release in those mixtures which are composed when first thorium is mixed with natural lithium or ⁶Li for a volume fraction from 0% to 100% and then the variable thorium-lithium composition is mixed with Be or Pb for a volume fraction from 0% to 100%.