Enhancing Heat Transfer Performance In Simulated Fischer–Tropsch Fluidized Bed Reactor Through Tubes Ends Modifications

Fluidized bed reactors are essential in a wide range of industrial applications, encompassing processes such as Fischer–Tropsch synthesis and catalytic cracking. The optimization of performance and reduction in energy consumption in these reactors necessitate the use of efficient heat transfer mechanisms. The present work examines the considerable impact of tube end geometries, superficial gas velocity, and radial position on heat transfer coefficients within fluidized bed reactors. It was found that the tapered tube end configurations have been empirically proven to improve energy efficiency in fluidized bed reactors significantly. For example, at a superficial gas velocity of 0.4 m/s, the tapered end form\u27s local heat transfer coefficient (LHTC) demonstrated a significant 20% enhancement compared to the flat end shape. The results and findings of this work make a valuable contribution to the advancement of complex models, enhance the efficiency of fluidized bed reactor processes, and encourage further investigation into novel tube geometries

The Relativistic Linear Singular Oscillator

Exactly-solvable model of the linear singular oscillator in the relativistic configurational space is considered. We have found wavefunctions and energy spectrum for the model under study. It is shown that they have correct non-relativistic limits.Comment: 14 pages, 12 figures in eps format, IOP style LaTeX file (revised taking into account referees suggestions

Remarkable enhancement in crystalline perfection, second harmonic generation efficiency, optical transparency, and laser damage threshold in potassium dihydrogen phosphate crystals by L-threonine doping

Effect of L-threonine (LT) doping on crystalline perfection, second harmonic generation (SHG) efficiency, optical transparency, and laser damage threshold (LDT) in potassium dihydrogen phosphate (KDP) crystals grown by slow evaporation solution technique (SEST) has been investigated. The influence of doping on growth rate and morphology of the grown crystals has also been studied. Powder x-ray diffraction data confirms the crystal structure of KDP and shows a systematic variation in intensity of diffraction peaks in correlation with morphology due to varying LT concentration. No extra phase formation was observed which is further confirmed by Fourier transform Raman (FT-Raman) studies. High-resolution x-ray diffraction curves indicate that crystalline perfection has been improved to a great extent at low concentrations with a maximum perfection at 1 mol % doping. At higher concentrations (5 to 10 mol %), it is slightly reduced due to excess incorporation of dopants at the interstitial sites of the crystalline matrix. LDT has been increased considerably with increase in doping concentration, whereas SHG efficiency was found to be maximum at 1 mol % in correlation with crystalline. The optical transparency for doped crystals has been increased as compared to that of pure KDP with a maximum value at 1 mol % doping

The Ankle- Brachial Pressure Index AS A Predictor of Coronary Artery Disease Severity

Background: Atherosclerosis is a diffuse disease process, being present in one vascular bed predicts its presence in the others. Ankle –brachial pressure index (ABI) is a non invasive test proved to be sensitive and specific in detecting and assessing the severity of peripheral arterial disease. Patients and Methods: One hundred fifty patients (150) were enrolled in this study, from January - June 2007; all were referred to the Iraqi Centre for Heart Diseases (I.C.H.D.) for further evaluation, with request for further assessment of CAD or lower extremity peripheral arterial disease. Clinical data and physical examination were performed; ABI was calculated by measurement of systolic pressure on both ankles over both dorsalis pedis and posterior tibial arteries and on both arms over the brachial arteries by using a Doppler stethoscope. The Ankle –Brachial Pressure Index (ABI) calculation was made by taking the lowest value for the ankle pressure and the highest value for the brachial pressure. The normal value for the ABI range from (1-1.4), a cutoff value of < 0.90 was used to identify low ABI. All patients underwent diagnostic coronary angiography and quantitative coronary angiography (QCA) was used to identify the lesion length and severity of stenosis. The severity of CAD was quantified by GENSINI score, the number of diseased vessels and the number of significant lesions. Results: The mean Ankle-Brachial Pressure index (ABI) for the sample was 0.908±0.31 (range 0- 1.53), the mean GENSINI score was 44.02±40 (range 0-148), GENSINI score was zero in 30 (20%) patients, 40 (26%) were having no diseased vessel, 41(27%) having single, and 43 (28.7%) double and 26 (17%) triple vessel disease. ABI was inversely related to the extent of CAD assessed by GENSINI (p-value 0.015), number of diseased vessels (p-value 0.009), and number of significant lesions (p-value 0.021). ABI < 0.9 was recorded in 51 patients (34%) and a low ABI was an independent factor for a higher GENSINI scores (p-value 0.043) and a higher number of diseased vessels (p-value 0.0001). Patients who were referred with PAD were found to have significantly lower ABI than the rest of the sample (p=0.0001), and a coexisted CAD was detected in 15 out of 20 (75%) patients. Conclusions: ABI was a useful bedside clinical test that predicts the severity of the CAD in patients who are already suffering from or suspected to have ischemic heart disease

A Combined EM and Visual Tracking Probabilistic Model for Robust Mosaicking: Application to Fetoscopy

Twin-to-Twin Transfusion Syndrome (TTTS) is a progressive pregnancy complication in which inter-twin vascular connections in the shared placenta result in a blood flow imbalance between the twins. The most effective therapy is to sever these connections by laser photo-coagulation. However, the limited field of view of the fetoscope hinders their identification. A potential solution is to augment the surgeon’s view by creating a mosaic image of the placenta. State-of-the-art mosaicking methods use feature-based ap- proaches, which have three main limitations: (i) they are not robust against corrupt data e.g. blurred frames, (ii) tem- poral information is not used, (iii) the resulting mosaic suf- fers from drift. We introduce a probabilistic temporal model that incorporates electromagnetic and visual tracking data to achieve a robust mosaic with reduced drift. By assuming planarity of the imaged object, the nRT decomposition can be used to parametrize the state vector. Finally, we tackle the non-linear nature of the problem in a numerically stable manner by using the Square Root Unscented Kalman Filter. We show an improvement in performance in terms of robustness as well as a reduction of the drift in comparison to state-of-the-art methods in synthetic, phantom and ex vivo datasets

Transmission function properties for multi-layered structures: Application to super-resolution

We discuss the properties of the transmission function in the k-space for a generic multi-layered structure. In particular we analytically demonstrate that a transmission greater than one in the evanescent spectrum (amplification of the evanescent modes) can be directly linked to the guided modes supported by the structure. Moreover we show that the slope of the phase of the transmission function in the propagating spectrum is inversely proportional to the ability of the structure to compensate the diffraction of the propagating modes. We apply these findings to discuss several examples where super-resolution is achieved thanks to the simultaneous availability of the amplification of the evanescent modes and the diffraction compensation of the propagating modes

CO-INOCULATION WITH RHIZOBIUM AND BACILLUS SP TO IMPROVE THE PHOSPHORUS AVAILABILITY AND YIELD OF WHEAT (Triticum aestivum L.)

ABSTRACT Intensive cropping has resulted-in wide spread deficiency of nutrients in most of the soils and situation is becoming more serious because of a increase in the use of high priced chemical fertilizers and their negative influence on the environment. Exploitation of biological intervention mainly phosphate solublizing bacteria (PSB) has attracted great attention, as they have enormous potential in providing soil phosphorus for plant growth, by increasing the availability of accumulated phosphate through solubilization. A field experiment was conducted to investigate the effect of Rhizobium and Bacillus, alone and in combination on the yield parameters of wheat. Uniform dose of N and K (160 and 60 kg ha ), grain protein (11.84%) and 1000 grain weight (62 g) were higher in co-inoculation of Rhizobium and Bacillus. It was also recorded that coinoculation of Rhizobium and Bacillus improved the grain yield up to 17.5% as compared to control. In single inoculation Bacillus gave better result and showed an increase of 7.7% in grain yield. Phosphorus uptake by grains (25.29 kg ha -1 ) was maximized by co-inoculation followed by Bacillus inoculation. Available phosphorus in post harvest sample of soil was recorded (16.27 mg kg -1 ) which was significantly higher than all other treatments. Results clearly demonstrated that co-inoculation of Rhizobium and Bacillus sp enhanced the availability of phosphorus and exert positive effect on the growth and yield of crop

Hadamard upper bound on optimum joint decoding capacity of Wyner Gaussian cellular MAC

This article presents an original analytical expression for an upper bound on the optimum joint decoding capacity of Wyner circular Gaussian cellular multiple access channel (C-GCMAC) for uniformly distributed mobile terminals (MTs). This upper bound is referred to as Hadamard upper bound (HUB) and is a novel application of the Hadamard inequality established by exploiting the Hadamard operation between the channel fading matrix G and the channel path gain matrix Ω. This article demonstrates that the actual capacity converges to the theoretical upper bound under the constraints like low signal-to-noise ratios and limiting channel path gain among the MTs and the respective base station of interest. In order to determine the usefulness of the HUB, the behavior of the theoretical upper bound is critically observed specially when the inter-cell and the intra-cell time sharing schemes are employed. In this context, we derive an analytical form of HUB by employing an approximation approach based on the estimation of probability density function of trace of Hadamard product of two matrices, i.e., G and Ω. A closed form of expression has been derived to capture the effect of the MT distribution on the optimum joint decoding capacity of C-GCMAC. This article demonstrates that the analytical HUB based on the proposed approximation approach converges to the theoretical upper bound results in the medium to high signal to noise ratio regime and shows a reasonably tighter bound on optimum joint decoding capacity of Wyner GCMAC

Immune or genetic-mediated disruption of CASPR2 causes pain hypersensitivity due to enhanced primary afferent excitability

Human autoantibodies to contactin-associated protein-like 2 (CASPR2) are often associated with neuropathic pain, and CASPR2 mutations have been linked to autism spectrum disorders, in which sensory dysfunction is increasingly recognized. Human CASPR2 autoantibodies, when injected into mice, were peripherally restricted and resulted in mechanical pain-related hypersensitivity in the absence of neural injury. We therefore investigated the mechanism by which CASPR2 modulates nociceptive function. Mice lacking CASPR2 (Cntnap2 ) demonstrated enhanced pain-related hypersensitivity to noxious mechanical stimuli, heat, and algogens. Both primary afferent excitability and subsequent nociceptive transmission within the dorsal horn were increased in Cntnap2 mice. Either immune or genetic-mediated ablation of CASPR2 enhanced the excitability of DRG neurons in a cell-autonomous fashion through regulation of Kv1 channel expression at the soma membrane. This is the first example of passive transfer of an autoimmune peripheral neuropathic pain disorder and demonstrates that CASPR2 has a key role in regulating cell-intrinsic dorsal root ganglion (DRG) neuron excitability

Pruning strategies for efficient online globally consistent mosaicking in fetoscopy

Twin-to-twin transfusion syndrome is a condition in which identical twins share a certain pattern of vascular connections in the placenta. This leads to an imbalance in the blood flow that, if not treated, may result in a fatal outcome for both twins. To treat this condition, a surgeon explores the placenta with a fetoscope to find and photocoagulate all intertwin vascular connections. However, the reduced field of view of the fetoscope complicates their localization and general overview. A much more effective exploration could be achieved with an online mosaic created at exploration time. Currently, accurate, globally consistent algorithms such as bundle adjustment cannot be used due to their offline nature, while online algorithms lack sufficient accuracy. We introduce two pruning strategies facilitating the use of bundle adjustment in a sequential fashion: (1) a technique that efficiently exploits the potential of using an electromagnetic tracking system to avoid unnecessary matching attempts between spatially inconsistent image pairs, and (2) an aggregated representation of images, which we refer to as superframes, that allows decreasing the computational complexity of a globally consistent approach. Quantitative and qualitative results on synthetic and phantom-based datasets demonstrate a better trade-off between efficiency and accuracy