Negatively Correlated Diversity Branches Using Various Modulation Methods and Maximal Ratio Combining

A diversity system using maximal ratio combining, and in which the diversity branches are negatively correlated, is considered. The performance of some digital systems, namely PSK, DPSK, CFSK, and NFSK, are compared. The error probability as a function of frequency differences between the branches is given. Also, error probability averaged over time delay difference τ is given as a function of direct as well as indirect signal-to-noise ratio. The sensitivity of the error probability to the form of the density function of τ is investigated.Mth order of diversity is considered, but second- and third-order diversity are specifically analyzed.     

Statistical properties of mobile-to-mobile land communicationchannels

Statistical properties of mobile-to-mobile land communication channels have been developed. In particular, the level-crossing rate and duration of fades of the envelope, the probability distribution of random FM, the expected number of crossings of the random phase and random FM of the channel, and the power spectrum of random FM of the channel have been considered     

Evanescent field absorption sensor for detection of copper(Ⅱ) in water using multimode optical fiber

The evanescent field absorption sensor for the detection of trace amount of copper (Ⅱ) in water is experimentally analyzed with the etched step index multimode plastic clad silica (PCS) fiber. The designed sensor is sensitive to copper (Ⅱ) content in water with a range up to 250 ppm.     

Energy Efficient Resource Scheduling Using Optimization Based Neural Network in Mobile Cloud Computing

The mobile cloud computing has become an emerging technology where the mobile computing is integrated with cloud computing to process the mobile data. Besides the advantages of mobile cloud computing, there are some issues which include power consumption, resource scarcity, quality of service, security and computational cost. In this paper, in order to minimize total power consumption with better performance, the neural network based optimization methods using artificial neural network and convolutional neural network models were implemented by varying variance and loudness. From the experimental results it is observed that, by using optimization in the neural network, the power consumption has been reduced by 53.68% and obtained improvement using convolutional neural network which further reduced the power consumption by 30.3% with minimum root mean square error compared with other algorithms.

     

Low shear viscosity and crystallization in dilute solutions of polymers at high pressures: Falling body viscometry of high molecular weight polyethylene solutions

A specially designed falling body viscometer has been used to obtain low shear viscosities of dilute solutions of high molecular weight polyethylene in decalin and for detecting phase transitions at high pressures. The method provides valuable rheological data at pressures that correspond to those I lubrication and some extrusion processes. In addition, the method enables detection of phase transitions, such as crystallization, that result in detectable changes in rheology. The influence of pressure as high as 0.6 GPa ( ～ 80.000 psi) is illustrated here through a study of crystallization, with verification from light scattering and calorimetry.     

A framework for morphological evolution vis-à-vis phase transitions in polymer solutions

When a polymer crystallizes from solution, it is well known that the resulting morphology depends on whether any liquid–liquid phase separation (LLPS) has preceded crystallization. In addition to the dense morphology that results when crystallization occurs directly from a homogeneous solution, at least three other distinctly different morphologies are produced if crystallization follows LLPS. Although much work has been reported in this regard, a framework that can relate the path that a process might follow across a phase diagram to the consequent morphology is lacking. We report here the fundamental elements of a simple thermodynamic framework that serves to identify the driving forces that produce these different morphologies. It is based on identification of the nucleating phase, if any, in LLPS and coupling it with the domain in which nucleation of crystallization occurs. The essential elements of the framework for morphological evolution are demonstrated by relating the sequence of phase transitions to the morphology which can result in the crystallized polymer when a polymer solution is cooled from a homogeneous state at a high temperature. Four distinctly different morphologies are shown to evolve, depending on whether crystallization occurs (a) directly from a homogeneous solution (dense); (b) following binodal liquid–liquid phase separation, LLPS, with nucleation of the polymer-rich phase (GMP—globular microporous); (c) following spinodal LLPS (FMP—fibrillar microporous); or (d) following binodal LLPS with nucleation of the solvent-rich phase (CTMP—cell-tunnel microporous). An important implication of the framework is that a predictable sequence of “dense → GMP → FMP → CTMP → dense” morphologies has to arise with increase in overall polymer concentration in such solutions. The framework also serves to identify conditions, such as passage through specific temperature/concentration regions in the phase diagram, that would increase the likelihood of forming mixed or coexisting morphologies. However, it is still necessary to develop appropriate kinetic models to predict sizes of the morphological components within each of the four morphologies. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 1343–1355, 1999     

The influence of mobile-to-mobile land communication channelspectrum on the error rate of binary DPSK and NFSK matched filterreceivers

The effect of a specific fading correlation function derived for a mobile-to-mobile land communication channel on the performance of differentially coherent PSK and noncoherent FSK matched filter receivers is investigated. The bit error probability, irreducible error rate, and the degradation in signal-to-noise ratio (SNR) are specifically derived for each system. The effect of the fading bandwidth on the performance of the system is also investigated     

Evanescent field absorption sensor for detection of copper （Ⅱ） in water using multimode optical fiber

The evanescent field absorption sensor for the detection of trace amount of copper （Ⅱ） in water is experimentally analyzed with the etched step index multimode plastic clad silica （PCS） fiber. The designed sensor is sensitive to copper （Ⅱ） content in water with a range up to 250 ppm.     

Study of interactions in PVC-plasticizer systems using low-molecular-weight analogs

Because PVC mixes very slowly with plasticizer, analogs of PVC were used to obtain heats of mixing via direct calorimetry. Initial studies were done with DBP, DOP, and DOS plasticizers and chloroform, 1,3-dichloropropane, and 2,4-dichloropentane as the analogs. Simultaneous calculations for the enthalpy of mixing were done using the UNIFAC-FV model. Both the propane and the pentane derivatives behaved according to the predictions of UNIFAC. Both experiments and calculations suggested that 1,3-dichloropropane is a better model for PVC than 2,4-dichloropentane.     

Detection and determination of manganese concentration in water using a fiber Bragg grating coupled with nanotechnology

Through this paper we experimentally demonstrate the fabrication of a fiber Bragg grating (FBG) chemical sensor to detect and determine the manganese concentration in water and compare our results with sophisticated spectroscopic methods, such as atomic absorption spectrometry and the inductively coupled plasma method. Here we propose a simple method to develop a thin layer of gold nanoparticles above the etched grating region to enhance the sensitivity of the reflected spectrum of the FBG. By doing so, we achieve a sensitivity of 1.26 nm/parts per million in determining the trace level of Mn in water. Proper reagents are used to detect manganese in water.