Performance of Digboi Refinery Modernization Project From Geotechnical Aspects — Investigation and Observations

Digboi Refinery is the world’s oldest refinery in simple form which is producing oil since 1889 till present with its modernized setup. Its first well was dug manually during 1889 and crude oil was found at 54m depth only. This phenomenon has encouraged establishing an industry on oil producing business, and accordingly a form of first refinery was comeout in 1889. The Digboi Refinery modernization project was taken up in large scale in order to overcome the technological obsolescence of the old refinery. Subsequently a number of other major projects were undertaken by Assam Oil Division to further revamp and modernise Digboi Refinery, which is in fact commissioning during 2007 onward as a completely modernizied refinery. Geotechnical investigations for this modernization project was started during 1987 and completed during 1992. As a whole the investigation works were completed under time bound work of three different phases of investigations with various engineering requirements. Besides laboratory investigations, field investigation includes mainly boreholes with SPT, DCPT, SCPT, VST, CBRT and Block vibrations tests. After careful studies, based on the field and laboratory investigations various types of shallow and deep foundations were suggested. Design and constructions were made based on the suggestion provided more particularly to overcome the problems pertaining to the high seismicity of the area and potential to dynamic liquefaction point of view and executed the same at site accordingly. Observations were made till date are found highly satisfactorial to engineering aspects

Finding F.O.S for Flow Type Landslide With Static Liquefaction At Karshingsa – A Case Study

Karshingsa is a hilly terrain situated in lower Himalayan region under Arunachal Pradesh in India. It expresses occurrence of severe landslides of debris flow nature almost every year as and when consecutive 3-month rainfall precipitation during peak monsoon period exceeds about 2,300 mm, all along the lower Himalayan region of Eurasian plateau most particularly in Karshingsa area. Study carried out in the lower belt of Arunachal Himalaya for about more than one decade proclaims that 45%-55% landslides are flow type origin, the debris of which are flowing like liquid. Mechanism of such flow failure is static liquefaction developed in a circumstance of its geological origin, in which the discrete boundary exists. The conventional method for finding the critical ‘c’ & ‘φ’ related to old failure zone is not valid for occurrence of such landslide. Hence, stability analysis demands a new approach with procedures. This new process accepts the real occurrence of flow slide in a study area called Karshingsa of north eastern region of India. Present study generates a new approach and recognition of new method of stability analysis for occurrence of flowtype landslide under unique situation of geotechnical aspect

Solutions to Integrals Involving the Marcum Q-Function and Applications

Novel analytic solutions are derived for integrals that involve the generalized Marcum Q-function, exponential functions and arbitrary powers. Simple closed-form expressions are also derived for the specific cases of the generic integrals. The offered expressions are both convenient and versatile, which is particularly useful in applications relating to natural sciences and engineering, including wireless cpmmunications and signal processing. To this end, they are employed in the derivation of the channel capacity for fixed rate and channel inversion in the case of correlated multipath fading and switched diversity.Comment: 15 Pages, 2 Figure

Performance evaluation of high mobility OFDM channel estimation techniques

In wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) has been adopted due to its robustness to multipath fading and high data rate transmissions. At the other hand, the performance of OFDM systems severely degraded due to multi-path fading and Doppler frequency shifts in mobile systems, which causes inter-carrier-interference (ICI). Thus, Estimation of channel parameters is required at the receiver using a pre designed estimator where pilot tones are inserted in each OFDM symbol. In this paper, a random pilot data are generated and inserted in each OFDM symbol at equally spaced locations. The performance test of Least Square (LS) and Linear Minimum Mean Square (LMMSE) estimation methods are proposed with Discrete Fourier Transform (DFT) based on both LS and LMMSE, where different ITU channel models are considered in order to compare their performance for data transmission in high mobile systems with different Doppler frequencies exceeds 200 Hz and minimal number of pilots

A novel delay dictionary design for compressive sensing-based time varying channel estimation in OFDM systems

Compressive sensing (CS) is a new attractive technique adopted for Linear Time Varying channel estimation. orthogonal frequency division multiplexing (OFDM) was proposed to be used in 4G and 5G which supports high data rate requirements. Different pilot aided channel estimation techniques were proposed to better track the channel conditions, which consumes bandwidth, thus, considerable data rate reduced. In order to estimate the channel with minimum number of pilots, compressive sensing CS was proposed to efficiently estimate the channel variations. In this paper, a novel delay dictionary-based CS was designed and simulated to estimate the linear time varying (LTV) channel. The proposed dictionary shows the suitability of estimating the channel impulse response (CIR) with low to moderate Doppler frequency shifts with acceptable bit error rate (BER) performance

Optical Asymmetric Modulation for VLC Systems

The explosive growth of connected devices and the increasing number of broadband users have led to an unprecedented growth in traffic demand. To this effect, the next generation wireless systems are envisioned to meet this growth and offer a potential data rate of 10 Gbps or more. In this context, an attractive solution to the current spectrum crunch issue is to exploit the visible light spectrum for the realization of high-speed commutation systems. However, this requires solutions to certain challenges relating to visible light communications (VLC), such as the stringent requirements of VLC-based intensity modulation and direct detection (IM/DD), which require signals to be real and unipolar. The present work proposes a novel power-domain multiplexing based optical asymmetric modulation (OAM) scheme for indoor VLC systems, which is particularly adapted to transmit high-order modulation signals using linear real and unipolar constellations that fit into the restrictions of IM/DD systems. It is shown that the proposed scheme provides improved system performance that outperforms alternative modulation schemes, at no extra complexity

Performance Analysis of Coherent and Noncoherent Modulation under I/Q Imbalance

In-phase/quadrature-phase Imbalance (IQI) is considered a major performance-limiting impairment in direct-conversion transceivers. Its effects become even more pronounced at higher carrier frequencies such as the millimeter-wave frequency bands being considered for 5G systems. In this paper, we quantify the effects of IQI on the performance of different modulation schemes under multipath fading channels. This is realized by developing a general framework for the symbol error rate (SER) analysis of coherent phase shift keying, noncoherent differential phase shift keying and noncoherent frequency shift keying under IQI effects. In this context, the moment generating function of the signal-to-interference-plus-noise-ratio is first derived for both single-carrier and multi-carrier systems suffering from transmitter (TX) IQI only, receiver (RX) IQI only and joint TX/RX IQI. Capitalizing on this, we derive analytic expressions for the SER of the different modulation schemes. These expressions are corroborated by comparisons with corresponding results from computer simulations and they provide insights into the dependence of IQI on the system parameters. We demonstrate that the effects of IQI differ considerably depending on the considered system as some cases of single-carrier transmission appear robust to IQI, whereas multi-carrier systems experiencing IQI at the RX require compensation in order to achieve a reliable communication link

Effect of Styrene Butadiene Rubber Latex on Mechanical Properties of Eco Concrete: Limestone Powder Concrete

To make concrete a truly green material, viable cement substitutes are available. This experimental investigation is performed to study the effect of using limestone powder (LSP) and styrene butadiene rubber (SBR) latex in the concrete mix. In this work, a concrete with 1:1.8:3 cementitious material:sand:gravel and water/cement ratio w/c of 0.5 is produced. First, LSP is used with 0, 5, 10, 15, and 20% replacements by weight of cements. The fineness of the LSP is measured using sieve No. 200 and showed about 30% pass. Second, and to improve the matrix of concrete due to the dilution effect, four ratios of SBR latex (0, 5, 10, and 15%) are added by weight of cements to the mix for each LSP ratio. Compressive strength at ages of 3, 7, 14, 28, and 90 days is tested for the concrete specimens mixed with LSP only to examine its effect on concrete strength’s development with time, whereas strengths are recorded at the age of 28 days for the other concretes. Three prisms were cast for each ratio and tested at 28 days. The results show general improvements in terms of compressive and flexural strengths

Adsorption of methylene blue by biochar produced through torrefaction and slow pyrolysis from switchgrass

The present work involves a study of sorption of methylene blue (MB) by charcoal samples produced through torrefaction and pyrolysis processes from switchgrass (Panicum virgatum). The adsorption of MB was determined using the spectrometric analysis method at various pH, temperature values and MB concentrations. The heat treatment temperature during biochar production significantly influenced the surface chemistry of biochars indicating that biochar samples, based on their thermal history alone, can behave significantly differently in the rhizosphere or in their ability to adsorb pollutants. The pH of the solution containing MB significantly affected its adsorption by biochars but trends were markedly different. The concentration of MB was also affected adsorption behavior of the two charcoals. The results indicate that biochars can be produced with desired properties to solve specific agricultural or environmental needs

E-cigarette exposure causes early pro-atherogenic changes in an inducible murine model of atherosclerosis

Introduction: Evidence suggests that e-cigarette use (vaping) increases cardiovascular disease risk, but decades are needed before people who vape would develop pathology. Thus, murine models of atherosclerosis can be utilized as tools to understand disease susceptibility, risk and pathogenesis. Moreover, there is a poor understanding of how risk factors for atherosclerosis (i.e., hyperlipidemia, high-fat diet) intersect with vaping to promote disease risk. Herein, we evaluated whether there was early evidence of atherosclerosis in an inducible hyperlipidemic mouse exposed to aerosol from commercial pod-style devices and e-liquid.Methods: Mice were injected with adeno-associated virus containing the human protein convertase subtilisin/kexin type 9 (PCSK9) variant to promote hyperlipidemia. These mice were fed a high-fat diet and exposed to room air or aerosol derived from JUUL pods containing polyethylene glycol/vegetable glycerin (PG/VG) or 5% nicotine with mango flavoring for 4 weeks; this timepoint was utilized to assess markers of atherosclerosis that may occur prior to the development of atherosclerotic plaques.Results: These data show that various parameters including weight, circulating lipoprotein/glucose levels, and splenic immune cells were significantly affected by exposure to PG/VG and/or nicotine-containing aerosols.Discussion: Not only can this mouse model be utilized for chronic vaping studies to assess the vascular pathology but these data support that vaping is not risk-free and may increase CVD outcomes later in life