Investigation of biogas and hydrogen production from waste water of milk-processing industry in Turkey

This study is conducted to determine the potential for producing both biogas and hydrogen from a milk-processing waste water in Turkey. The results of this study indicate that a maximum of 54.2 million m³ biogas/yr and 12,670 ton H₂/yr can be produced from milk-processing waste water. A total of $15.1 million worth of energy may be supplied every year from the produced biogas. Some Reference calculations for the production of biogas and the economic evaluation are carried out using actual data taken from the plant. Overall hydrogen production energy efficiency for different types of reforming and for different ambient temperatures ranges between 19 and 70% whereas the overall exergy efficiency for 900 °C reforming and different ambient temperatures changes between 8 and 48%, respectively.     

Spinning viscose textile yarn into a zinc-aluminum-containing precipitation bath under manufacturing conditions

Conclusions Viscose textile yarn has been prepared by spinning in a zinc-aluminum-containing precipitation bath under manufacturing conditions.The yarn-spinning process in a zinc-aluminum-containing bath is stable, and is accompanied by an increased evolution of carbon disulfide and hydrogen sulfide.Viscose textile yarn spun in a zinc-aluminum-containing bath conforms to the All-Union State Standard and is characterized by a lower elongation and an increased swelling and shrinkage.Processes of warping and weaving the yarn have been carried out without any difficulties.O. M. Savchenko, senior engineer of the Klinsk Khimvolokno Industrial Association, also took part in this work.Translated from Khimicheskie Volokna, No. 6, pp. 34–35, November–December, 1988.     

Geomagnetic Effects from Expanding Plasma Formation of a High‐Altitude Nuclear Explosion

The geomagnetic variations on the Earth's surface due to the magnetohydrodynamic stage of expansion of the plasma formation of highaltitude nuclear explosions are considered. It is shown that the distribution of the signal amplitudes in the distances from the source obeys a certain regularity. An analysis of measurement data and numerical modeling of the magnetohydrodynamic signal confirms that the temporal shape and phases of the signal are determined by its propagation by three channels: an electromagnetic wave in the atmosphere, highconductivity layers of the ionosphere, and the lithosphere, which possesses finite electrical conductivity. Agreement between the results of numerical modeling and measurements is obtained. A comparison of the disturbances caused by explosions and substorms indicate they are difficult to separate in the far field of the explosion.     

The Sectoral Sweeper Scheme for Wireless Sensor Networks: Adaptive Antenna Array Based Sensor Node Management and Location Estimation

We introduce a novel sensor node management and location estimation method referred as sectoral sweeper (SS) scheme that uses an adaptive antenna array (AAA) at a central node in wireless sensor networks (WSNs). With the SS scheme, the central node can activate or deactivate the nodes in a desired region which is specified by beam direction and beam width of the transmit beam and also by minimum and maximum thresholds (R _min and R _max) for the received signal strength indicator (RSSI) of signals received by the nodes. In order to perform a specified task that is associated with a Task_id, two different beams are transmitted, which are task region beam and routing region beam to switch the nodes into active or routing modes. Since our scheme does not require any additional software or hardware for node management and location estimation in sensor nodes, the deficiencies of tiny sensors are effectively eliminated. The proposed scheme is shown to reduce the number of sensing nodes and the amount of data traffic in the network, thus leading to considerable savings in energy consumption and prolonged sensor lifetime. Ayhan Erdogan graduated from Turkish Naval Academy, Istanbul, in 1992. He received the MSdegree from the Computer Engineering, Naval Sciences and Engineering Institute, Turkish Naval Academy, Istanbul, in 2003. He attended to a one year training on Automatic Data Processing (ADP) Officer in Middle East Technical University, Turkey, in 1996. He worked as a Project Officer for Turkish Armed Forces Integrated Communication Systems Project developed by Turkish General Stuff, from 1996 until 2001. He is currently a PhD student at the Electronics Engineering and Computer Science Department, Sabanci University, Istanbul, Turkey. His current research interests include Wireless Sensor Networks and Security for Ad hoc Networks. Vedat Coskun was born in Istanbul, Turkey, in 1962. He was graduated from Turkish Naval Academy, Istanbul, Turkey, in 1984. He received the M.Sc. degree from the Computer Science Department, Naval Post Graduate School, CA, USA, in 1990 and the Ph.D. degree from the Computer Engineering Department, Yildiz Technical University, Istanbul, in 1998. He managed the wargaming software development group in Turkish Naval Military Wargaming Center for 5 years. Hewas teaching assistant, faculty member and chairman with the Computer Engineering Department, Turkish Naval Academy. He was part-time visiting professor with Gebze Institute of Technology. He is currently an Assistant Professor with the Department of Information Technology, ISIK University, Istanbul, Turkey. His current research interests include algorithm design, wireless sensor and actuator networks, and cryptography Adnan Kavak was born in Usak, Turkey, in 1970. He received the B.S. degree from the Electrical and Electronics Engineering Department, Middle East Technical University, Ankara, Turkey, in 1992. He received the MS and PhD. degrees from the Electrical and Computer Engineering Department, The University of Texas at Austin, TX, USA, in 1996 and 2000, respectively. He was a satellite control engineer with Turksat Satellite Control Center, Ankara, Turkey, from December 1992 to May 1994. He worked as a Senior Research Engineer at Wireless Systems Laboratory, Samsung Telecommunications America in Richardson, TX, USA, from January 2000 to July 2001. He then joined Kocaeli University, Turkey, in August 2001 and worked as an Assistant Professor there until May 2005. Currently, he is the director ofWireless Communications and Information Systems (WINS) Research Center, and an Associate Professor with the Computer Engineering Department, Kocaeli University, Turkey. His current research interests include 3G and next generation wireless networks, software radios, smart antenna systems, resource allocation in 3G networks, and wireless sensor networks.     

Monitoring the parameters of a reactor by low-frequency pressure pulsations

Conclusions The method considered has a quite high sensitivity for the appearance of the initial stage of onset of deviations from the normal course of the thermophysical processes in the core.The safety factor is determined more reliably from the start of transition to an unstable cycle of operation of the core.Translated from Atomnaya Énergiya, Vol. 51, No. 2, pp. 96–99, August, 1981.     

Influences of pore geometry, porosity and permeability on initial water saturation — An empirical method for estimating initial water saturation by image analysis

Investigation of the relationships between two-dimensional pore geometrical data, from image analysis of thin sections, and initial water saturation, measured by conventional laboratory techniques on core plugs, reveals that the volumes of small pores within the pore space have strong influences on initial water saturation. A North American and a North Sea reservoir were investigated and empirical models specific to each reservoir show that 72% and 73% of the variance in initial water saturation can be explained by image data. The average amount that estimated initial water saturation differs from the experimentally measured initial water saturation is ± 3% and ± 3.5%, respectively, for the two reservoirs.It is also shown that the negative relationship between porosity or permeability and initial water saturation, which commonly have been used for prediction of saturation, are not universal but depend on the degree of pore size variation. Significant negative relationships between permeability and initial water saturation occur for rocks with relatively uniform pore systems but different pore sizes. For rocks with varying degrees of non-uniform pore systems, quantitative determination of pore structure is essential in order to estimate initial water saturation.The porosity classification technique used in this study is shown to be useful for determining the pore geometrical parameters which are significant for the prediction of initial water saturation. This technique could be used to evaluate initial water saturations of larger numbers of samples including samples too small for conventional testing.     

Development of a neural network based saturation model forsynchronous generator analysis

This paper presents a new approach to model synchronous generator saturation based on a feedforward artificial neural network (ANN) model. The machine loading conditions, excitation levels and rotor positions are all included in the modeling process. The nonlinear saturation characteristics of a three-phase salient-pole synchronous machine rated at 5 kVA and 240 V is studied using the ANN model. An appropriate selection of input/output pattern for the ANN model training based on an error back-propagation scheme is developed using the on-line small-disturbance responses and the well-known maximum-likelihood estimation algorithm. The developed ANN model is implemented in the generator dynamic transient stability study requiring only small computational alteration in saturation model representation     

Chemical Blowing Approach for Ultramicroporous Carbon Nitride Frameworks and Their Applications in Gas and Energy Storage

A scalable, template‐free synthetic strategy is presented for the preparation of ultramicroporous carbon nitride frameworks (CNFs) through a chemical blowing approach by using ammonium chloride as blowing agent and hexamethylene tetraamine as the C and N precursor and a subsequent potassium hydroxide chemical activation is employed to obtain CNFs with surface areas up to 1730 m² g^?1 along with a high nitrogen content of 13.3 wt%. CNFs showed CO₂ uptake capacities up to 5.74 mmol g^?1 at 1 bar and 1.67 mmol g^?1 at 0.15 bar, 273 K along with a very high CO₂/N₂ selectivity. In addition, H₂ uptake capacity of 1.9 wt% and the isosteric heats of adsorption (Q _st) value of 9.0 kJ mol^?1 at zero coverage have been also observed. Moreover, the presence of nitrogen‐doped graphene walls in CNFs also facilitated their application as supercapacitors, with capacitance values up to ≈114 F g^?1 at 0.5 A g^?1, along with a good cyclability and capacitance retention. This approach effectively extends unique surface properties of carbon nitrides into the micropore regime for effective capture of small gases and energy storage applications. Importantly, textural properties of CNFs can be simply tuned by judicious choice of organic precursors and the blowing agent.