A Channel Model for Underground Sensor Networks in the Mixture of Crude Oil,Water and Soil

Future enhanced oil recovery technology can greatly benefit from the wireless sensor networks to effectively operate in underground oil reservoirs. In such a case, millimeter scale sensor nodes with antennas at the same scale have to be deployed in the confined underground oil reservoir fractures. This necessitates the sensor nodes to be operating in the THz frequency range. In this paper, the propagation based on electromagnetic （EM） waves in the Terahertz band （0.1-120.0 THz） through a crude oil/water mixture and soil medium is analyzed in order to explore its applicability in underground oil reservoir assessments. The developed model evaluates the total path loss and the absorption loss that an EM wave experiences when propagating through the crude oil/water mixture and soil medium. Our results show that sensors can communicate successfully for distances up to 1 cm. Furthermore, we have determined the existence of two transmission bands, in which the path loss is below 100 dB. Among those, the frequency window, which provides the best performance, is determined as 70 THz to 85 THz. Different path and absorption loss schemes are considered, which suggests that the 70 THz to 85 THz band is suitable for sensor communications in a medium of crude oil/water mixture and soil.     

Dietary selenium- and vitamin E-induced alterations in some rabbit tissues

The present study was designed to investigate and compare the effects of dietary selenium (Se) and vitamin E on some physiological parameters and histological changes in liver, heart, and skin tissues, as well as the blood parameters and the related enzymes. Both sex young rabbits were fed with deficient (9.8 micrograms/kg diet), adequate (225 micrograms/kg diet), and rich (4.2 mg/kg diet) Se and vitamin E diets for 12-15 wk for this purpose. As the plasma Se levels and the erythrocyte glutathione (GSH) peroxidase activity decreased (79.8 +/- 9.4 ng/mL and 2.0 +/- 0.3 U/g Hb, respectively) in the deficient group, these values increased (100.4 +/- 2.7 ng/mL and 14.5 +/- 4.3 U/g Hb) in the rich group significantly with respect to the control group. The other antioxidant enzyme activities and the related element levels did not change significantly in either one of the experimental groups. Although the platelet counts of the two experimental groups were not different from the control values, the collagen and the adenosine diphosphate (ADP) stimulated platelet aggregation rate and intensity increased in the deficient group (p < 0.05) and decreased very significantly (p < 0.001) in the rich group. In both of the experimental groups, as the percentage values of the neutrophils decreased, the lymphocytes and the eosinophils increased significantly. According to the light microscopic investigations, the observed lesions of considerable intensity within the tissues that elicit cell degenerations were more pronounced in the animals fed with the rich diet than in those fed with the deficient diet. The deficiency as well as toxicity of Se and the deficiency of vitamin E caused several alterations in the physiological functions of the tissues, and these alterations were supported by the histological lesions within these tissues.     

Use of Transmission Electron Microscopy for the Characterization of Rapid Thermally Annealed, Solution-Gel, Lead Zirconate Titanate Films

The microstructure and preferred orientations of rapid thermally annealed Pb(Zr_0.53,Ti_0.47)O₃ films, deposited on Pt/Ti/SiO₂/Si electrode/substrates by solution-gel spinning, have been investigated using analytical and high-resolution electron microscopy and X-ray diffraction. The temperature of pyrolysis of the PZT films was found to influence the preferred orientation of the film: lower temperatures (350°C) favored a (111) orientation, whereas higher temperatures (420°C) favored a (100) orientation. Excess Pb was used to control the A-site stoichiometry of the film particularly at the film surface where Pb-deficient crystals could often be observed. The absence of these crystals was shown to be correlated with an improvement in the dielectric response.     

Effect of medication on biomechanical properties of rabbit bones: heparin induced osteoporosis

BACKGROUND: We hypothesize that the integrity of the latissimus dorsi muscle graft used to wrap the heart may affect the clinical outcome of patients undergoing dynamic cardiomyoplasty. METHODS: By correlating the pathologic findings with their clinical course in five patients who died 1 month to 6 years after dynamic cardiomyoplasty operation, we sought to discern findings that might shed light on the pathophysiology of cardiomyoplasty. RESULTS: Of the two patients who had a limited clinical response, one had an atrophic, edematous latissimus dorsi muscle with fatty infiltration resulting from cardiac cachexia, and the other had insufficient length of latissimus dorsi muscle to cover a large heart. The remaining patients responded well clinically without signs of pump failure and died at various intervals, mostly of arrhythmias. Autopsy findings included the following: (1) one patient with ischemic cardiomyopathy as the underlying disease had development of rich vascularity in the interface between the muscle wrap and the epicardium; whereas in four others with idiopathic cardiomyopathy, such evidence of collateralization was far less evident. (2) There was a variation in the skeletal muscle transformation achieved, with the fraction type I fatigue-resistant fiber in the muscle wrap ranging from 60% to 100%, in spite of the identical transformation protocol used. Such variation is believed to be genetically based. (3) In one patient, the skeletal muscle was paced to contract at 30 to 50 times/minute (2:1 ratio) for more than 5 years. Nevertheless, the pathologic specimen of the muscle wrap showed only minimal interstitial fibrosis. (4) Relatively thin muscle wrap around the heart found at autopsy could be atrophy but most likely was related to muscle transformation, which is known to reduce muscle mass and increase capillary density. (5) All skeletal muscle grafts showed geometric conformation to the shape of the epicardium and grossly looked as if they were an additional layer of the ventricular wall. Such conformation may facilitate the modulation of the ventricular remodelling process in the failing heart, as has been described both in clinical and experimental studies. CONCLUSIONS: Our findings are consistent with and support a number of mechanisms proposed for cardiomyoplasty. Thus preservation of latissimus dorsi muscle graft integrity may be important in the success of dynamic cardiomyoplasty.     

Residual concentration method for the problem of diffusion on the surface of a spherical cavity

The classical spherical diffusion equation is expressed in terms of a residual concentration. Thus, it becomes possible to eliminate the second derivative of the concentration with respect to the radial coordinate from the diffusion equation. This, in turn, leads to the advantage that diffusion on the surface of a spherical cavity can be studied by considering the cavity surface only. The case of a point source on the cavity surface is presented as an example for the application of the proposed Residual Concentration Method.     

Wıreless Communıcatıons Beyond 5 g: Teraherzwaves,Nano-Communıcatıons and the Internet of Bıo-Nano-Thıngs

Two promising technologies cosidered for the Beyond 5G networks are the terahertz and nano-technologies. Besides other possible application areas they hold the commitment to numerous new nano-scale solutions in the biomedical field. Nano-technology, as the name implies, examines the construction and design of nano-sized materials. These two interconnected emerging technologies have the potential to find application in quite many areas, one of the most importan being healthcare. This overview paper discusses the specifics of these technologies, their most important characteristics and introduces some of the trends for their application in the healthcare sector. In the first section terahertz frequency radio waves and their specific properties depending on the surrounding environment are discussed, followed by an introduction to nano-scale communications. Terahertz waves mandate the use of nano-scale antennas, which in turn brings us to the concept of nano-scale nodes. Nano-scale nodes are units that can perform the most basic functions of nano-machines and inter-nano-machine communications, which allow distributed nano-machines to perform more complex functions. Beyond 5G the development of these nano-communications is expected to lead to the emergence of new complex network systems. In the second part of this paper the paradigms of the Internet of Nano Things, molecular commnications and the Internet of Bio-Nano Things are discussed followed by details on their integration in healthcare related applications. The main goal of the article is to provide an introduction to these intriguing issues discussing advanced nano-technology enablers for Beyond 5G networks such as terahertz and molecular communications, nano-communications between nano-machines and the Internet of Bio-Nano-Things in light of health related applications.

     

Enhancement of uranyl ion uptake by prestructuring of acrylamide–maleic acid hydrogels

Acrylamide–maleic acid (AAm–MA) hydrogels were prepared by gamma‐irradiation of their aqueous solutions. UO₂⁺² ion uptake on P(AAm–MA) hydrogels was investigated using two types of gel systems prepared by a simple irradiation method and a prestructured reaction. It has been observed that gels prestructured with UO₂⁺² ions adsorbed approximately 15–20% more UO₂⁺² ions than gels prepared in pure water (the usual method). It was also found that the uranyl ion adsorption capacity of hydrogels increased with an increasing amount of maleic acid in the gel system and an increasing concentration of uranyl ion in the solution. A possible interaction mechanism between the groups in the copolymeric gels and UO₂⁺² ion has been proposed based on the stoichiometry and the spectroscopic evidence. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 284–289, 2000     

Effect of Nb Doping on the Microstructure of Sol—Gel-Derived PZT Thin Films

Aliovalent Nb doping (<10 at.%) of sol—gel-derived lead zirconate titanate (PZT) thin films was investigated with the intention of improving the ferroelectric properties. Nb addition was found to significantly alter the perovskite crystallization by stabilizing the transient pyrochlore phase, resulting in the retention of pyrochlore second phases and an increase in the perovskite lateral grain size and columnarity. The occurrence and composition of Zr-rich (surface) pyrochlore phases were found to depend on Nb concentration, annealing temperature, and Pb content. The observed changes in ferroelectric and dielectric properties as a function of Nb dopant addition were found to be strongly influenced by microstructural effects and the occurrence of pyrochlore, and hence the intrinsic effects of Nb incorporation in the perovskite lattice could not be directly ascertained.     

Static and dynamic buckling analyses of spherical sandwich caps

For some ranges of sandwich shell parameter the axisymmetric and asymmetric buckling curves for spherical sandwich caps under a uniform hydrostatic pressure are similar to those for the corresponding homogeneous caps. In the first part of this investigation two methods are presented to obtain the buckling curves for the sandwich caps directly from the buckling curves for the homogeneous caps without going through any buckling analysis.In the second part of the investigation the axisymmetric dynamic snap-through buckling behavior of the sandwich cap under a uniform step pressure is studied. The numerical results show that the dynamic buckling curve for the sandwich cap is similar to that for the homogeneous cap. Moreover, the methods of estimating buckling loads presented for the static buckling analysis are also applicable to the dynamic buckling analysis.