Heat wheel is a heat exchanger in which the working fluid is air and it has parallel and counter current flow layout. These type heat exchangers are used for enthalpy recovery and/or air dehumidification processes. By means of numerous micro channels they have, it is enable for the heat wheels to transfer the heat so quickly and in a short span of time, which makes them superior. In this paper, performance of the heat wheel used for enthalpy recovery has been numerically determined. Utilizing Computational Fluid Dynamics (CFD) algorithm, the alteration of the wheel efficiency with time has been investigated for optimum rotation speed. With the help of ANSYS Fluent™ software in which calculations have been made, the temperature distributions by location have been presented graphically. Consequently, it is found that maximum efficiency of the heat wheel is 52.62 %.

The effects of restoration on the experimental dynamic characteristics of historical masonry Molla Siyah Mosque in Trabzon, Turkey, are investigated in this paper. Firstly, the initial situation and the implemented restoration works of the mosque are mentioned in detail. Then, the experimental dynamic behaviors of the mosque before and after the restoration are obtained by using the Ambient Vibration Tests. High sensitivity seismic accelerometers with cables are used during the tests. The collected signals are evaluated by Enhanced Frequency Domain Decomposition Technique, and experimental natural frequencies, mode shapes and damping ratios of the mosque are determined for the initial and restoration cases. The obtained results are compared with each other and restoration effects on the dynamic behavior of the mosque are discussed in detail.

The usage of bio-fuel for transportation fuel has become mandatory to reduce the greenhouse gas emissions and increase the fuel quality. It is well known that the bio-fuels such as bio-ethanol and bio-butanol are produced by the fermentation process and the final concentrations of these alcohols in fermentation broth are very low. Therefore, effective and selective separation processes are required to be used. Pervaporation is a cost effective and selective membrane process that separates azeotropic, close-boiling-point mixtures from each other. It is commercially used as a hybrid process with distillation in the fermentation plant. The performance of this method depends on the productivity, durability, stability, and selectivity of the membrane. Thus, academic studies related to the pervaporation membrane production are still in progress. The purpose of this study is dehydration of bio-butanol by using pervaporation. Montmorillonite clay incorporated carboxymethyl cellulose composite membrane has been prepared. Effects of temperature and butanol-water concentration on separation performance have been investigated.

The aim of this study is to assess adsorption characteristics of R134a on a commercially available silica gel. Experimental study is performed by A constant volume variable pressure method is used in experimental study. Adsorption process are realized at different temperatures between 293.15 and 320.15 K and for pressures up to 500 kPa. Parameters in the Dubinin-Astakhov (DA) equation for the silica gel – R134a pair is computed by the use of measured experimental data. Adsorption isotherms are obtained by using DA equation for the silica gel – R134a pair. Further, the adsorption enthalpy are provided for the specimen investigated. It is observed that the value of the heat of adsorption is always quite higher than the vaporization enthalpy of the adsorbent in the range of 1.2 to 1.8 depending on the specific adsorbed mass of R134a. Obtained data from the present experimental study can be used for the design of cooling and refrigeration systems in which adsorption process is employed.

One of the major enviromental problems around the world is disposal of waste tyres without any purpose. Disposal of waste tyres is an increasing enviromental problem. Also because of high content of valuable chemicals and other compounds hidden in the waste tyres, disposal of them is an economical problem as well. Pyrolysis is a thermochemical process that can be used for recovery of the valuable chemicals in the waste tyre. Pyrolysis is a recycling process in which, liquid product can be used as a fuel directly or can be mixed with petroleum refined oils. Derived gaseous product can also be used as a fuel and solid product can be considered as a fuel and low grade carbon black. In this work, granulated waste tyres have been pyrolyzed in a fixed bed reactor under different conditions of temperature, heating rate and inert purging gas (N2) flow rate. The purpose of the study was to optimize the pyrolysis parameters in order to produce the highest amount of oil. 400°C, 450°C and 500°C were selected and the maximum yield of liquid product was observed at 450°C. Among the heating rates of 10°C/min, 15°C/ min and 20°C/min; 10°C/min was the parameter that gave maximum oil yield. And while working at 450°C and 10°C/min; N2(g) flow rate was examined by using 0.5 L/min, 1 L/min and 1.5 L/min. The maximum oil yield was observed at 1 L N2(g) /min. According to the results of the study; at 450°C, with a heating rate of 10°C/min and 1 L N2(g)/min gave the maximum yield of oil, which is 53.33 wt.%. The pyrolytic oil from waste tyre had the Gross Calorific Value of 42.6 MJ/kg which is very close to that of commercial diesel no 2 (around 42-46 MJ/kg). The pyrolytic oil produced is a promising fuel and can be used as a source of energy after some future work for make it suitable for use in vehicles or in other areas like factories or houses etc.

The aim of this paper is to present new analytical and computational approaches for assessing the structural safety of “false vaults” structures like Trulli, and more generally for corbelled structures. Starting from a deep investigation on the building techniques of Trulli and on the employed materials, we underline that the stability of such structures is justifiable only by admitting the transmission of forces along parallels that is by admitting the three-dimensional nature of their structural behavior. We proposed two equilibrium methods for assessing the stability of such complex masonry structures, both capable of taking into account their three-dimensional behavior. The first method is based on the Thrust Network Analysis, a three-dimensional computational method for finding compression only spatial networks in equilibrium with the external loads contained in the thickness of the masonry. The second method is based on a further improvement of the so-called Modified Corbelling Theory, an analytical approach based on the limit overturning equilibrium and specifically developed for the analysis of corbelled domes.

Road pavement serviceability is primarily governed by the type of vehicles anticipated to use the facility. Along with the size of traffic loads, climatic conditions affect the behavior of the materials in a pavement structure. The relative strength loss in a layer due to its drainage characteristics and the total time it is exposed to near-saturation moisture conditions is represented by drainage coefficients. There is a need for computerized methodologies for thickness design of flexible asphalt pavements (granular base course) for a wide variety of pavement uses providing users the capability to conduct structural analysis of special pavement structures. An algorithm for a computer-based procedure towards the calculation of the layer thickness of flexible pavements has been developed. The design equation used is that described by the American Association of State Highway and Transportation Officials. The present work deals with the effect of drainage on the total thickness of the structure as it directly influences the cost of large infrastructure projects like roads. The output of different cases solved is presented in table and schematic form. Changes in technology related to pavement design and construction practices will necessitate revisions to currently used computing techniques. Improvements in computing times which will affect the cost of computerized methods available to engineers are to be suggested in the near future. Empirically supported pavement designs used nowadays in Greece require modifications based on regional experience and on a better assessment of the drainage conditions prevailing in each area crossed by a roadway project. Since design considerations constantly change, it is obligatory to shift towards more sophisticated design methods.