Plasmonic Devices in the Terahertz and Optical Frequency Domains

We are living in an age where the evolution of semiconductor devices and components is contingent upon their miniaturization and seamless integration with the rest of the circuitry. Unfortunately, it is anticipated that electronic systems will soon approach the theoretical design limits of size and bandwidth, and it poses to be a serious concern for the development of high-speed information technologies. Replacement of electronic pulses that act as communication signals with electromagnetic surface waves offers a very promising solution, particularly in terms of device miniaturization and the heart of this optimism are the plasmonic waves arising due to collective electron oscillations at the surface of a conductor. Surface plasmon polaritons propagating along a metal-dielectric interface at optical frequencies have lately been a subject of immense research interest, mainly due to their reduced wavelength at least by an order of magnitude. Hence, miniaturized wave devices can be created at optical frequencies. Terahertz plasma waves, on the other hand, exist in infinitesimally thin plasma regions formed inside a transistor substrate, and are observed at much lower frequencies in the far-infrared regime. Due to essentially a two-dimensional nature of the plasma region, a much higher wavelength reduction factor that can exceed well beyond 100 is achievable. Furthermore, the boundary conditions due to the transistor terminals along with electric biasing create unstable resonance conditions that eventually lead to radiation in the terahertz frequency range. Such phenomena provide bright prospects for creating highly miniaturized terahertz devices. A reliable and efficient electromagnetic (EM) analysis for multilayer geome tries has gained further significance due to the emergence of plasmonic structures in the optical as well as terahertz frequency domains. In this regard, integral equation (IE) techniques are ideally suited due to their efficient handling of mutilayer structures. Although the presence of thin layers poses a challenge to any EM analysis technique, here the procedure is simplified due to the infinitesimally thin nature of the plasma region, which can be analyzed as a conducting sheet, with the same current flowing on either side of the sheet. Essential to any IE technique is an efficient and systematic formulation of Green functions (GFs) and their subsequent computation. In this dissertation, a transmission-line network based approach is adopted to derive spectral domain GFs for an infinitesimally thin sheet in a layered medium. The associated spatial domain counterparts are then computed through the Sommerfeld integrals (SIs). The extraordinary electromagnetic properties of plasmonic devices are demonstrated by a presentation of the properties of plasmonic antennas and a super-resolution imaging scheme which is able to resolve objects separated only by a few nanometers

Design and implementation of proposed 320 bit RC6-cascaded encryption/decryption cores on altera FPGA

This paper attempts to build up a simple, strong and secure cryptographic algorithm. The result of such an attempt is “RC6-Cascade” which is 320-bits RC6 like block cipher. The key can be any length up to 256 bytes. It is a secret-key block cipher with precise characteristics of RC6 algorithm using another overall structure design. In RC6-Cascade, cascading of F-functions will be used instead of rounds. Moreover, the paper investigates a hardware design to efficiently implement the proposed RC6-Cascade block cipher core on field programmable gate array (FPGA). An efficient compact iterative architecture will be designed for the F-function of the above algorithm. The goal is to design a more secure algorithm and present a very fast encryption core for low cost and small size applications

SHEAR BEHAVIOR OF FIBROUS REINFORCED CONCRETE WIDE BEAMS

When a reinforced concrete beam does not have enough shear strength and / or little amount of secondary rebar are reinforced, the "shear failure" is possible. Such type of failure is not acceptable in civil engineering due it does not indicate any prior notice before the complete failure of the intended structural member. One of the most popular solutions to overcome such shortcoming is the addition of steel fibers due to the ability for enhancing mechanical properties and ductility. Wide beams are such beams that have high width if compared with its thickness, such structural members are frequent in many reinforced concrete building systems and may also face "shear failure" during its service life. The current study investigates the structural behavior of the Steel Fiber Reinforced Concrete Wide Beams by proposing an experimental program comprising casting and testing of twenty beams specimen. The effective shear spans to depth ratio ratios were 2.5 and 3.5, respectively. Two nominal strength levels 30 MPa "Normal strength concrete" and 60 MPa "High strength concrete are also included. The types of steel fibers used are the "End Hocked" as well as the "Staggered" in 0.5% and 1.5% volume fractions for each one. The results showed that the addition of steel fibers enhances the consequent mechanical properties and the relevant structural behavior of wide beams to a serious concern. Furthermore, the addition of steel fibers modified the shear failure mode to "flexural".

Nalidixic acid screening test in detection of decreased fluoroquinolone susceptibility in salmonella typhi isolated from blood

OBJECTIVE: To determine the validity of nalidixic acid screening test in the detection of high MICs of fluoroquinolone against Salmonella(S.) typhi isolated from blood and correlate zone diameters of ofloxacin with that of MIC value for nalidixic acid sensitive and resistant strains. DESIGN: Cross-sectional analytical study. PLACE AND DURATION OF STUDY: Clinical Microbiology Laboratory of the Aga Khan Hospital, Karachi from January 2002 to December 2003.METHODS: Two hundred S. typhi isolates from blood were included for nalidixic acid screening and ofloxacin susceptibility. Antibiotic susceptibilities for both the antibiotics were obtained by disc diffusion method whereas MICs were determined by standard agar dilution method as recommended by NCCLS guidelines. Sensitivity, specificity and correlation between both antimicrobial susceptibility methods were calculated and results expressed as scattergrams.RESULTS: The results broadly classify S. typhi isolates into nalidixic acid resistant strains with no zone of inhibition around 30 mug nalidixic acid disc and nalidixic acid sensitive strains with mean zone of inhibition of 24.9 mm. All S. typhi isolates with ofloxacin MIC of capital ZHE, Cyrillic 0.125 microg/ml were found to be nalidixic acid resistant (MIC capital ZHE, Cyrillic32 microg/ml) whereas the isolates with ofloxacin MIC 0.06 microg/ml were nalidixic acid sensitive (MIC 8 microg/ml). Screening for nalidixic acid resistance was found to be 100% sensitive and 97% specific in identifying S. typhi strains with reduced susceptibility to fluoroquinolone (MIC capital ZHE, Cyrillic 0.125 microg/ml).CONCLUSION: Nalidixic acid resistance as a screening method is proved to be significant in identifying S. typhi isolates with reduced susceptibility to fluoroquinolones. It is also suggested that inhibition zone of 25 mm around 5 microg ofloxacin disc is appropriate as a selection criterion to detect S. typhi isolates with reduced susceptibility to fluoroquinolones

Equivalent Modulus of Asphalt Concrete Layers

A flexible pavement structure usually comprises more than one asphalt layer, with varying thicknesses and properties, in order to carry the traffic smoothly and safely. It is easy to characterize each asphalt layer with different tests to give a full description of that layer; however, the performance of the whole; asphalt structure needs to be properly understood. Typically, pavement analysis is carried out using multi-layer linear elastic assumptions, via equations and computer programs such as KENPAVE, BISAR, etc. These types of analysis give the response parameters including stress, strain, and deflection at any point under the wheel load. This paper aims to estimate the equivalent Resilient Modulus (MR) of the asphalt concrete layers within a pavement structure by using their individual MR values. To achieve this aim, eight samples were cored from Iraqi Expressway no. 1; they had three layers of asphalt and were tested to obtain the MR of each core by using the uniaxial repeated loading test at 25 and 40 °C. The samples were then cut to separate each layer individually and tested for MR at the same testing temperatures; thus, a total of 60 resilient modulus tests were conducted. A new approach was introduced to estimate the equivalent MR as a function of the MR value for each layer. The results matched the values obtained by KENPAVE analysis

Electromagnetic scattering of two-dimensional electronic systems

No abstract available

Effects of the alcoholic extract of white mulberry leaves on behavioral performance of rats

White mulberry tree is a genus of Morus in the family Moraceae. The leaves and root of this tree have been traditionally medical applications as a laxative, analgesic, diuretic, antitussive, and sedative agent as well as for reducing blood pressure. The present study aimed to investigate the effects of the alcoholic extract of the leaves of white mulberry tree on the behavioral performance of rats. In this study, 24 male Wistar rats were kept under the condition of normal 12-12 h light-dark cycle for adaptation with the animal house environment and experiments location (23-27C0). All animals have access to food and water ad libitum and were weighed weekly to control their natural growth. These rats were divided into four groups of six rats. First, the open field behavioral test was performed on all rats and after 35 days the gavage feeding of the alcoholic extract of white mulberry leaves was performed. Group one received distilled water and groups two to four respectively received concentrations of 150, 300, and 600 mg per unit body weight of the alcoholic extract white mulberry leaves. Then, open field behavioral test was performed again. Results showed that regarding the number of visited zones there is a significant difference between the control group and the groups receiving the extract. Up to the sixth week that the condition of all rats was identical the rate of weight increase was the same and from the seventh week on that the gavage of the hydro-alcoholic extract of white mulberry leaves began, the trend of the weight increase of the control group was different than that of the other groups. due to the effect of the alcoholic extract of white mulberry leaves on the weight of the rats at concentrations above, it can be concluded that the extract is effective for weight loss. Findings of open field test showed that this extract has anti-anxiety effects while imposing no toxic effects

Sistim gotong royong dalam masyarakat pedesaan Propinsi Daerah Istimewa Aceh

Sistem gotong-royong merupakan suatu hal yang bertambah penting, apalagi kalau diingat bahwa generasi muda Indonesia nanti akan mengetahui bagaimana mereka dari generasi yang lalu mengembangkan dan membina nilai-nilai luhur yang terpancar dari unsur budaya mereka. Buku ini memuat berbagai informasi yang tumbuh dan berkembang dalam masyarakat tempo dulu mengenai sistim gotong royong dalam masyarakat pedesaan Propinsi Daerah Istimewa Aceh

Monitoring health status and quality assessment of leaves using terahertz frequency

The demand for effective use of water resources has increased due to ongoing global climate transformations in the agriculture science sector. Cost-effective and timely distributions of the appropriate amount of water are vital not only to maintain a healthy status of plants leaves but to drive the productivity of the crops and achieve economic benefits. This paper presents a novel, and non-invasive machine learning (ML) driven approach using terahertz waves with a swissto12 material characterization kit (MCK) in the frequency range of 0.75 to 1.1 THz in real-life digital agriculture interventions, aiming to develop a feasible and viable technique for precise estimation of water content (WC) in plants leaves on different days. For this purpose, multi-domain features are extracted from frequency, time, time-frequency domains using observations data to incorporate three different machine learning algorithms such as support vector machine, (SVM), K-nearest neighbour (KNN) and decision-tree (D-Tree). The results demonstrate SVM outperformed other classifiers using 10-fold and leave-one-observations-out cross-validation for different days classification with an overall accuracy of 98.8%, 97.15%, and 96.82% for coffee, pea-shoot, and spinach leaves respectively. In addition, using SFS technique, coffee showed a significant improvement of 15%, 11.9%, 6.5% in computational time for SVM, KNN and D-tree. For pea-shoot, 21.28%, 10.01%, and 8.53% of improvement was noticed in operating time for SVM, KNN and D-Tree classifiers. Lastly, in baby-spinach leaf, SVM exhibited an upgrade of 21.28%, 10.01%, and 8.53% was noticed in operating time for SVM, KNN and D-Tree classifiers and which eventually enhanced the classification accuracy. Thus, the proposed method incorporating ML using terahertz waves can be beneficial for precise estimation of WC in leaves and can provide prolific recommendations and insights for farmers to take proactive actions in relations to plants health monitoring

Contextual Beamforming: Exploiting Location and AI for Enhanced Wireless Telecommunication Performance

The pervasive nature of wireless telecommunication has made it the foundation for mainstream technologies like automation, smart vehicles, virtual reality, and unmanned aerial vehicles. As these technologies experience widespread adoption in our daily lives, ensuring the reliable performance of cellular networks in mobile scenarios has become a paramount challenge. Beamforming, an integral component of modern mobile networks, enables spatial selectivity and improves network quality. However, many beamforming techniques are iterative, introducing unwanted latency to the system. In recent times, there has been a growing interest in leveraging mobile users' location information to expedite beamforming processes. This paper explores the concept of contextual beamforming, discussing its advantages, disadvantages and implications. Notably, the study presents an impressive 53% improvement in signal-to-noise ratio (SNR) by implementing the adaptive beamforming (MRT) algorithm compared to scenarios without beamforming. It further elucidates how MRT contributes to contextual beamforming. The importance of localization in implementing contextual beamforming is also examined. Additionally, the paper delves into the use of artificial intelligence schemes, including machine learning and deep learning, in implementing contextual beamforming techniques that leverage user location information. Based on the comprehensive review, the results suggest that the combination of MRT and Zero forcing (ZF) techniques, alongside deep neural networks (DNN) employing Bayesian Optimization (BO), represents the most promising approach for contextual beamforming. Furthermore, the study discusses the future potential of programmable switches, such as Tofino, in enabling location-aware beamforming