A New Modified MPPM for High‐Speed Wireless Optical Communication Systems

Previous work proposed combining multipulse pulse position modulation (MPPM) with pulse amplitude modulation to form multipulse amplitude and position modulation (MPAPM), which is a hybrid modulation that results in an improvement in bandwidth efficiency but a degradation in power efficiency. In this paper, to achieve greater power efficiency and a better data rate, we propose multipulse dual amplitude‐width modulation, based on MPAPM and pulse width modulation. The proposed scheme shows a remarkable improvement in data rate and a 1.5‐dB improvement in power efficiency over MPAPM, while sustaining the bandwidth efficiency. After introducing symbol structure, we present the theoretical expressions of spectral efficiency, the power requirements, and the normalized data rate, as well as the results of comparing the proposed modulation to MPPM and MPAPM.     

On the correlation between T<Subscript>2</Subscript> and tissue diffusion coefficients in exercised muscle: quantitative measurements at 3T within the tibialis anterior

PURPOSE: To assess the transverse relaxation time T(2) and diffusion coefficient D before and following exercise in the tibialis anterior muscle and determine whether T(2) and D values were correlated. METHODS: Measurements of T(2) and D were performed at 3 T within axial slices through the calf muscles of six healthy volunteers at 95 s intervals before and for 10-12 min after a dorsiflexion exercise to exhaustion. RESULTS: The mean +/- standard deviation (SD) of T(2) and D before exercise were 32 +/- 1.55 ms and 1.52 +/- 0.15 mum(2)/ms, and after exercise were 43 +/- 2.5 ms and 1.72 +/- 0.13 mum(2)/ms, respectively. The mean +/- SD inter-individual recovery times of the % change in T(2) and D after exercise were 7.9 +/- 4.2 and 10.9 +/- 7.0 min, respectively. The T(2) and D values showed a significant correlation throughout the experiments (r (2) = 0.45). CONCLUSIONS: The increase in T(2) of skeletal muscle after exercise is correlated with the increase of the diffusion coefficient D and the recovery times appear similar, indicating that any model used to explain T(2) increases with exercise must also account for increased diffusion coefficients.     

Exploration of Diazaspiro Cores as Piperazine Bioisosteres in the Development of σ2 Receptor Ligands

A series of σ2R compounds containing benzimidazolone and diazacycloalkane cores was synthesized and evaluated in radioligand binding assays. Replacing the piperazine moiety in a lead compound with diazaspiroalkanes and the fused octahydropyrrolo[3,4-b] pyrrole ring system resulted in a loss in affinity for the σ2R. On the other hand, the bridged 2,5-diazabicyclo[2.2.1]heptane, 1,4-diazepine, and a 3-aminoazetidine analog possessed nanomolar affinities for the σ2R. Computational chemistry studies were also conducted with the recently published crystal structure of the σ2R/TMEM97 and revealed that hydrogen bond interactions with ASP29 and π-stacking interactions with TYR150 were largely responsible for the high binding affinity of small molecules to this protein.     

Photovoltaic Properties of Multiferroic BiFeO3/BiCrO3 Heterostructures

We report a power conversion efficiency of ~0.01% in multistacking of BiFeO₃/BiCrO₃ bilayer thin films used as active layers in a photovoltaic (PV) device. The films were epitaxially deposited by pulse laser deposition onto (100) oriented CaRuO₃‐coated LaAlO₃ substrates and were subsequently illuminated with 1 sun (AM 1.5). The fill factor is determined to be 0.31%, a remarkable value for ferroelectric‐ and multiferroic‐based PV devices. Our results demonstrate that photocurrent density and photovoltage can be tuned by varying the thickness and number of respective bilayers in the improvement of PV properties of multiferroic heterostructures. The maximum photocurrent is generated at an optimal multilayer thickness of 60 nm, with its origin being mainly ascribed to the contribution of ferroelectric polarization.     

Calibration of time domain network analyzers

A calibration technique for a time domain reflectometry and transmission (TDR and TDT) measurement system as applied to network analysis is presented. The calibration corrects for the errors caused by the response of the measurement system. A complete physically-based model is established for the system. A set of calculable standards is developed to satisfy the time domain requirements for calibration. The calibration technique was applied to determining the model parameters of a commercial TDR and TDT system. The calibration enhanced the system bandwidth from 8 GHz to about 20 GHz. Experimental verification is given to demonstrate the validity and accuracy of the calibration technique     

SOOT FORMATION IN GAS TURBINE COMBUSTORS

Soot formation in the gas turbine combustors has serious effects on liner durability, carbon deposition and smoke emission.

In this work an analytical study is made to derive quantitative relationships for calculating temperature, unburned hydrocarbon and oxygen concentration from previous detailed experimental data. The quantities of the derived parameters are used in a soot formation model to predict soot concentration along the primary zone.

The soot concentration predicted compares favourably with experiment especially at full load conditions. This supports the capability of the model with the derived quantitative relationships in predicting soot concentration for different gas turbine combustors.     

Development of early age shrinkage stresses in reinforced concrete bridge decks

This paper describes the instrumentation and data analysis of a reinforced concrete bridge deck constructed on 3-span continuous steel girders in Evansville, West Virginia. An instrumentation system consisting of 232 sensors is developed and implemented specifically to measure strains and temperature in concrete deck, strains in longitudinal and transverse rebars, the overall contraction and expansion of concrete deck, and crack openings. Data from all sensors are automatically collected every 30 minutes starting at the time of placing the concrete deck. Measured strain and temperature time-histories were used to calculate the stresses, which were processed to attenuate the thermal effects due to daily temperature changes and isolate the drying shrinkage component. The results indicated that most of concrete shrinkage occurs during the first three days. Under the constraining effects from stay-in-place forms and reinforcement, early age shrinkage leads to elevated longitudinal stress, which is the main factor responsible for crack initiation.     

On Bayesian analysis of a finite generalized Dirichlet mixture via a Metropolis-within-Gibbs sampling

In this paper, we present a fully Bayesian approach for generalized Dirichlet mixtures estimation and selection. The estimation of the parameters is based on the Monte Carlo simulation technique of Gibbs sampling mixed with a Metropolis-Hastings step. Also, we obtain a posterior distribution which is conjugate to a generalized Dirichlet likelihood. For the selection of the number of clusters, we used the integrated likelihood. The performance of our Bayesian algorithm is tested and compared with the maximum likelihood approach by the classification of several synthetic and real data sets. The generalized Dirichlet mixture is also applied to the problems of IR eye modeling and introduced as a probabilistic kernel for Support Vector Machines.

Comparative assessment of cooling conditions,including MQL technology on machining factors in an environmentally friendly approach

Manufacturers need to continuously improve productivity and reduce the most disadvantages. In the current work, an experimental study has been carried out in order to evaluate the influence of different cutting parameters on the various machining factors such as surface roughness, cutting force, cutting power, metal removal rate, and tool wear during turning of X210Cr12 steel using a multilayer-coated tungsten carbide insert with various nose radii (r). Tests are designed according to Taguchi’s L₁₈ (2¹ × 3⁴) orthogonal array. ANOVA has been performed to determine the effect of the cutting conditions, and mathematical models have been developed through response surface methodology (RSM). The results indicate that the feed rate and the tool nose radius are the main affecting factors on surface roughness while both tangential force and cutting power are affected mainly by the depth of cut followed by the feed rate and the nose radius. Other special tests of long term have been established in order to study the wear evolution and consequently to determine the tool life. The results indicate also that minimum quantity lubrication (MQL) leads to an important improvement in terms of the cutting tool life by a gain of 23~40% compared to wet and dry machining. It has been found that the MQL is an interesting way to minimize lubrication cost and protect operator health and the environment while keeping better machining quality.     

Indexing important drugs from medical literature

Health maintenance is one of the foremost pillars of human society which needs up-to-date solutions to medical problems. The advancement in the biomedical field has intensified the—information load that exists in the form of clinic reports, research papers, or lab tests, etc. Extracting meaningful insights from this corpus is equally important as its progress—to make it valuable for recent medicine. In terms of biomedical text mining, the areas explored include protein–protein interactions, entity-relationship detection, and so on. The biomedical effects of drugs have significance when administered to a living organism. Biomedical literature is not widely explored in terms of gene-drug relations, hence needs investigation. Indexing methods can be used for ranking gene-drug relations. In scientific literature, Hirsch’s the h-index is usually used to quantify the impact of an individual author. Likewise, in this research, we propose the Drug-Index, a quantifiable measure that can be used to detect gene-drug relations. It is useful in drug discovery, diagnosing, personalized treatment using suitable drugs for relevant genes. For a strong and reliable gene-drug relationship discovery, drugs are extracted from a subset of MEDLINE—a bibliographic medical database. The detected drugs are verified from the PharmacoGenomics KnowledgeBase (PharmGKB)—a publicly available medical knowledgebase by Stanford University.