Development of a Robust Carrier Synchronizer for High Dynamic and Low Signal to Noise Ratio Signals in GPS Receivers

Wireless Personal Communications - In this paper, a robust carrier recovery loop for high dynamic and weak signals in GPS receivers is proposed. To achieve optimal tracking performance at...     

Phonon phase stability,structural, mechanical,electronic, and thermoelectric properties of two new semiconducting quaternary Heusler alloys CoCuZrZ (Z = Ge and Sn)

For meeting the energy demand, the development of new and novel thermoelectric (TE) materials for power generation is very vital. In this draft, we have theoretically investigated two new quaternary CoCuZrZ (Z = Ge and Sn) Heusler alloys for their structural, mechanical, electronic, and TE properties. In the energy minimization process, the alloys are found to be non-magnetic in the ground state. Based on calculated phonon dispersion curves, formation energy, and elastic constants, we propose that both CoCuZrGe and CoCuZrSn are stable. Furthermore, the mechanical properties indicate that CoCuZrGe (CoCuZrSn) has a brittle (ductile) nature. The electronic properties examined in Perdew-Burke-Ernzerhof (PBE), PBEsol, and modified Becke-Johnson (mBJ) potential, all predict that reported systems are narrow-gap semiconductors (SCs). In addition, the temperature dependent TE properties have been studied by calculating the electronic thermal conductivity (κ), Seebeck coefficient (S), power factor (PF) and electrical conductivity (σ/τ). The obtained positive value of S conveys the materials as p-type SCs, with a maximum value of 26.2 μV/K for CoCuZrGe and 28 μV/K for CoCuZrSn. The σ/τ, κ, and PF show increasing trends with rising temperature. The PF is found to be 1.55 × 10¹² WK⁻²m⁻¹s⁻¹ for CoCuZrGe and 1.38 × 10¹² WK⁻²m⁻¹s⁻¹ for CoCuZrSn. The proposed semiconducting Heusler alloys may receive attention for a range of TE and spintronic applications.     

Investigation of the impact of global warming on precipitation pattern of Saudi Arabia

This study has been carried out to forecast the impact of global warming on the precipitation pattern of Saudi Arabia by the end of year 2100. Simulation has been done using EdGCM model software (with available 8×10 resolution) developed at Columbia University on which there have been produced global precipitation maps for the seasonal and annual averages for the last 5 years (2096–2100). For each map, EdGCM grid values surrounding Saudi Arabia are used as input to one of the tools of Eagle point software called surface modelling (SM). SM is a new approach for downscaling global climate model results. SM software modelled out isohyets at 0.2 mm/day interval. The results indicate that the present pattern of precipitation (more in winter and less in summer) is going to change by almost equal occurrence of precipitation in all seasons for double_CO₂ (2CO₂) experiment. The 2CO₂ experiment indicates an increase of about 16.05% over the annual average precipitation across the country.     

A novel stimuli-responsive magnetic hydrogel based on nature-inspired tragacanth gum for chemo/hyperthermia treatment of cancerous cells

Journal of Polymer Research - Derivatives of formyl pyrazole were synthesized by the reaction of acetophenone, 4-methyl acetophenone, 3-acetyl furan, 3-acetyl thiophen and phenyl hydrazine...     

Recent advances and developments in advanced green porous nanomaterial for sustainable energy storage application

Journal of Porous Materials - Compared with traditional battery and super capacitor materials, nanomaterials can significantly improve ion transport and electron conductivity. There are many...     

A knowledge construction methodology to automate case-based learning using clinical documents

The case-based learning (CBL) approach has gained attention in medical education as an alternative to traditional learning methodology. However, current CBL systems do not facilitate and provide computer-based domain knowledge to medical students for solving real-world clinical cases during CBL practice. To automate CBL, clinical documents are beneficial for constructing domain knowledge. In the literature, most systems and methodologies require a knowledge engineer to construct machine-readable knowledge. Keeping in view these facts, we present a knowledge construction methodology (KCM-CD) to construct domain knowledge ontology (i.e., structured declarative knowledge) from unstructured text in a systematic way using artificial intelligence techniques, with minimum intervention from a knowledge engineer. To utilize the strength of humans and computers, and to realize the KCM-CD methodology, an interactive case-based learning system(iCBLS) was developed. Finally, the developed ontological model was evaluated to evaluate the quality of domain knowledge in terms of coherence measure. The results showed that the overall domain model has positive coherence values, indicating that all words in each branch of the domain ontology are correlated with each other and the quality of the developed model is acceptable.     

A longitudinal study of the relationships between haemostatic, lipid, and oestradiol changes during normal human pregnancy

BACKGROUND: Chronic leukemia is a disease characterized by the malignant proliferation of immunologically incompetent lymphocytes. The knowledge of open heart surgery in patients with this disorder is limited. METHODS: Twelve patients with chronic lymphocytic leukemia underwent open heart surgery (nine coronary artery bypass grafting (CABG), two aortic valve replacement (AVR), one CABG and AVR) from September 1991 to September 1996. There were nine males and three females with a mean age of 68 years (41-81 years). Staging was assigned according to the Rai Classification. There were seven Stage 0, two Stage I, zero Stage II, one Stage III and two Stage IV patients. Cardiopulmonary bypass (CPB) was performed using standard techniques of cannulation, moderate hypothermia and antegrade/retrograde cardioplegia. RESULTS: Hospital mortality occurred in two (17%) patients. Both patients died of sepsis. Hospital morbidity occurred in seven (58%) patients. The most common complications were infections. Five patients were found to have other malignancies (basal cell, laryngeal, prostate, bladder and breast cancers). Transfusion of blood products was required in eight (67%) patients. The average length of stay was 15 days (7-50 days). Follow-up was complete. Late mortality occurred in four patients at a mean of 7 months (1-18 months). All deaths were non-cardiac related (ruptured AAA, kidney failure, respiratory failure and sepsis). Six patients remain alive at a mean of 25 months (1-48 months). CONCLUSION: Hospital mortality and morbidity in patients with chronic lymphocytic leukemia undergoing open heart surgery are high. Infection is the leading cause of hospital death, as well as the most common complication. The majority of patients receive blood products during the course of their hospitalization. Late mortality is high and non-cardiac related. Based on these findings, a re-definition of the aims, goals and expectations of open heart surgery in patients with chronic leukemia is necessary. Suggestions in management are presented.     

基于超混沌Lorenz系统的自适应异步抗噪声保密通信方案

针对非实时通信对安全性要求高且信道中存在噪声的问题,提出了基于超混沌掩盖调制的自适应异步抗噪声保密通信方案。通信原理是由超混沌Lorenz系统生成四个状态变量的伪随机向量,并通过信号增益将它们调整到同一区间;再由分段线性混沌映射（PWLCM）生成两个向量,用于在四个状态变量之间随机切换选取和确定动态时滞步长,以生成载体信号;然后将预编码后的二进制信息成对掩盖到载体信号中,添加高斯噪声后发送出去。实验结果分析发现最小信号增益和噪声系数的比值稳定在一个小区间[0.08,0.11]内,如果把该比值设置成某个大于该区间上限的值,则比特误码率可达到零,因此接收端可在噪声信道中接收并完美恢复出被掩盖信号。该方案利用超混沌系统的非线性动力学特性,能够在噪声信道中自适应实现异步保密通信,数值仿真验证了其有效性。