A novel silicon Schottky diode for NLTL applications

The design and simulation of a novel silicon Schottky diode for nonlinear transmission line (NLTL) applications is discussed in this paper. The Schottky diode was fabricated on a novel silicon-on-silicide-on-insulator (SSOI) substrate for minimized series resistance. Ion implantation technology was used as a low-cost alternative to molecular beam epitaxy to approximate the delta (/spl delta/) doping profile, which results in strong nonlinear CV characteristics. The equivalent circuit model of the Schottky diode under reverse bias conditions was extracted from the S-parameter measurement performed on the diode. The measured CV characteristics show strong nonlinearity, the junction capacitance varies from 182 to 47.5 fF as the reverse bias voltage is varied from 0 to -5 V. A parasitic inductance of 40 pH was measured for the silicon Schottky diode, which is much smaller than a comparable sized GaAs Schottky diode. This small inductance is an advantage for the silicon Schottky diode offering improvement in the silicon NLTL performance.     

4D Printing of Shape Memory Materials for Textiles: Mechanism,Mathematical Modeling,and Challenges

Shape memory materials (SMMs) in 3D printing (3DP) technology garnered much attention due to their ability to respond to external stimuli, which direct this technology toward an emerging area of research, “4D printing (4DP) technology.” In contrast to classical 3D printed objects, the fourth dimension, time, allows printed objects to undergo significant changes in shape, size, or color when subjected to external stimuli. Highly precise and calibrated 4D materials, which can perform together to achieve robust 4D objects, are in great demand in various fields such as military applications, space suits, robotic systems, apparel, healthcare, sports, etc. This review, for the first time, to the best of the authors’ knowledge, focuses on recent advances in SMMs (e.g., polymers, metals, etc.) based wearable smart textiles and fashion goods. This review integrates the basic overview of 3DP technology, fabrication methods, the transition of 3DP to 4DP, the chemistry behind the fundamental working principles of 4D printed objects, materials selection for smart textiles and fashion goods. The central part summarizes the effect of major external stimuli on 4D textile materials followed by the major applications. Lastly, prospects and challenges are discussed, so that future researchers can continue the progress of this technology.     

Phase Inversion Strategy to Flexible Freestanding Electrode: Critical Coupling of Binders and Electrolytes for High Performance Li–S Battery

Development of flexible and freestanding electrode is attracting great attention in lithium–sulfur (Li–S) batteries, but the severe capacity fading caused by the lithium polysulfides (PSs) shuttle effect remains challenging. Herein, a completely new polymeric binder of polyethersulfone is introduced. Not only it enables massive production of flexible/current‐free electrode by a novel concept of “phase‐inversion” approach but also the resultant polymeric networks can effectively trap the soluble polysulfides within the electrode, owing to the higher hydrophilicity and stronger affinity properties than the routine polyvinylidene fluoride. Coupling with polysulfide‐based electrolyte, the Li–S cell shows a higher capacity of 1141 mAh g^?1, a lower polarization of 192 mV, and a more stable capacity retention with 100% Coulombic efficiency over 100 cycles at 0.25C. The advantages of favored binder and electrolyte are further demonstrated in lithium‐ion sulfur full battery with lithiated graphite anode, which demonstrates much improved performance than those previously reported. This work not only introduces a novel strategy for flexible freestanding electrodes but also enlightens the importance of coupling electrodes and electrolytes to higher performances for Li–S battery.     

A Dual-Band Printed Antenna Design Based on Annular Koch Snowflake Slot Structure

Wireless Personal Communications - The design of a fractal based slot antenna, to serve the dual-band communication applications, is proposed in this paper. The structure of the proposed antenna is...     

Organic geochemistry characterisation of crude oils from Mishrif reservoir rocks in the southern Mesopotamian Basin,South Iraq: Implication for source input and paleoenvironmental conditions

Seven crude oils from Cretaceous Mishrif reservoir rocks in the southern Mesopotamian Basin, South Iraq were studied to describe oil characteristics, providing information on the source of organic matter input and the genetic link between oils and their potential source rock in the basin. This study is based on biomarker and non-biomarker analyses performed on oil samples. The analysed oils are aromatic intermediate oils as indicated by high aromatic hydrocarbon fractions with more that 50%. These oils are also characterized by high sulfur and trace metal (Ni, V) contents and relatively low API gravity values (19.0–27.2° API). The results of this study indicate that these oils were derived from a marine carbonate source rocks bearing Type II-S kerogen that were deposited under sulphate-reducing conditions. This is primary achieved from their biomarkers and bulk carbon isotope and inorganic element contents (i.e., S, Ni and V). The absence of 18a (H)-oleanane biomarker also suggests a source age older than Late Cretaceous. The biomarker characteristics of these oils are consistent with those of the Late Jurassic to Early Cretaceous source rocks in the basin. However, biomarker maturity data also indicate that the oils were generated from early maturity source rocks. This appears to result from the type of kerogen of the source rock, characterized by a high-S kerogen (Type II-S).     

Vipulanandan model for the rheological properties with ultimate shear stress of oil well cement modified with nanoclay

In this study, the effect of clay nanoparticles (NC) and temperature on the rheological properties with ultimate shear stress and weight loss of the oil well cement (class H) modified with NC was investigated. The NC content was varied between 0 and 1% by the weight of the cement. The total weight loss at 800 °C for the oil well cement decreased from 6.10% to 1.03%, a 83% reduction when the cement was mixed with 1% of NC. The results also showed that 1% of NC increased the rheological properties of the cement slurry. The NC modification increased the yield stress (τ_o) and plastic viscosity (PV) by 5%–65% and 3%–16% respectively based on the NC content and the temperature of the cement slurry. The shear thinning behavior of the cement slurry with and without NC has been quantified using the Vipulanandan rheological model and compared with the Herschel-Bulkley model. The Vipulanandan rheological model has a maximum shear stress limit were as the Herschel-Bulkley model did not have a limit on the maximum shear stress. Based on the Vipulanandan rheological model the maximum shear stress produced by the 0% and 1% of NC at the temperature of 25 °C were 102 Pa and 117 Pa respectively hence an increase of 15% in the ultimate shear stress due to the addition of NC. The addition of 1% of NC increased the compressive strength of the cement by 12% and 43% after 1 day and 28 days of curing respectively. The modulus of elasticity of the cement increased with the additional of 1% NC by 6% and 76% after 1 day and 28 days of curing respectively. Effects of NC content and the temperature on the model parameters have been quantified using a nonlinear model (NLM). The NLM quantified the effect of NC treatment on all the model parameters.     

Bulk geochemical characteristics and carbon isotope composition of oils from the Sayhut sub-basin in the Gulf of Aden with emphasis on organic matter input,age and maturity

The Sayhut sub-basin is undergoing hydrocarbon exploration province in the Gulf of Aden, South Yemen. In this study, geochemical analyses were performed on three oil samples from two exploration wells in the Sayhut sub-basin. The results were used to describe the source organic matter input, age and maturity and to correlate between crude oils from different pay zones.The high saturated hydrocarbon values of more than 70% indicate that the analysed oils are normal crude oils and not degraded oils. This is supported by a complete suite of their normal alkanes and acyclic isoprenoids. The hydrocarbon distributions of normal alkane and isoprenoid with bulk carbon isotope data also suggest that the analysed oils are grouped into two genetic families and were generated from marine-source rock. The family A presents by one oil sample representing Harshiyat reservoir rock and characterized by relatively high Ph/Ph ratio > 2 and δ¹³C values of their saturated and aromatic hydrocarbon fractions range from ?26.1‰ to ?24.8‰. This oil family was derived from mixed organic matter with high contribution of a terrigenous organic matter input. The family A was deposited under suboxic conditions during the Late Cretaceous age. The family B presents by two oil samples representing Ghaydah and Habshiyah reservoir rocks and characterized by relatively low Ph/Ph ratio < 2 and carbon isotope less than ?23 for their saturated and aromatic hydrocarbon fractions. These oils were generated from source rock containing high contributions of marine organic matter (e.g., algal and microbial) with minor amount of land plant source inputs that was deposited in more reducing conditions. The family B oils are consistent with those of the Paleogene Umm Er Radhuma source rock.The hydrocarbon distribution and oil composition data also indicate that the analysed oils were generated from mature source rocks with a peak oil-window maturity.     

Treatment and restoration of used Mineral-Oil-Based hydraulic fluids from different machines. Part 1: Dewatering,filtration and effect of viscosity modifier

In this work, characterization and treatment of used hydraulic oil samples were performed in three steps. In the first step, the physical and the chemical properties of fresh and used hydraulic mineral oil samples from various centrifugal casting and pipe drawing machines were investigated according to ASTM D 6158. Results show that water content, solid particles count and depletion of additives have considerably affected most of the oil properties. Used oil samples failed in the appearance, thermal stability, oxidation stability, foaming tendency, water content and particles count.

In the second step, a simple methodology for dewatering and filtration was adopted. This methodology involved settling, followed by dry-air bubbling for oil dehydration and finally vacuum filtration. Such process successfully removed considerable portion of solid particles and water in used oil samples. Appearance, pour point, water content, particles count, and acid number were restored to the allowable limits. While water separability, oxidation stability, thermal stability and foaming tendency still failed the limits after treatment. It is obvious that additives will be needed to restore the latter properties.

In the third step, viscosity modifier additive was added to the oil samples to enhance viscous properties. A linear increase in kinematic viscosity was witnessed at 100°C, while at 40°C, an initial linear increase at low viscosities was followed by lower slopes at higher viscosities.     

Efficient multi‐hop wireless broadcast protocol in vehicular networks using automated threshold function design

Vehicular networking applications often use multi‐hop wireless broadcasting as a primary data dissemination mechanism. Therefore, protocols that efficiently and thoroughly propagate application data while adapting to a wide range of network density, vehicle distribution pattern, channel quality, and other conditions are critical for vehicular communications. Here, we design the Statistical Vehicular Broadcast (SVB) protocol to efficiently distribute data via multi‐hop broadcast in vehicular networks. First, we present an automated optimization technique for the design of threshold functions in statistical broadcasting methods. Next, we compare and analyze known statistical techniques, including different fundamental methods, assessment delay algorithms, and failsafe mechanisms. All combinations of these techniques are given threshold functions optimized using the proposed automated procedure then are evaluated in a wide range of simulations. High‐level statistical design principles and recommendations are established based on analysis of these results. Finally, we apply those principles to design SVB. It is evaluated in JiST/SWANS and is shown to achieve a high target reachability level while consuming less bandwidth than similar protocols across urban and highway vehicular networking scenarios.Copyright © 2014 John Wiley & Sons, Ltd.