Single side damage simulations and detection in beam-like structures

Beam-like structures are the most common components in real engineering, while single side damage is often encountered. In this study, a numerical analysis of single side damage in a free-free beam is analysed with three different finite element models; namely solid, shell and beam models for demonstrating their performance in simulating real structures. Similar to experiment, damage is introduced into one side of the beam, and natural frequencies are extracted from the simulations and compared with experimental and analytical results. Mode shapes are also analysed with modal assurance criterion. The results from simulations reveal a good performance of the three models in extracting natural frequencies, and solid model performs better than shell while shell model performs better than beam model under intact state. For damaged states, the natural frequencies captured from solid model show more sensitivity to damage severity than shell model and shell model performs similar to the beam model in distinguishing damage. The main contribution of this paper is to perform a comparison between three finite element models and experimental data as well as analytical solutions. The finite element results show a relatively well performanc

Međudjelovanje četiri-razinskog atoma u impulsnom svojstvenom stanju s jednomodnim poljem

We study the interaction between a four-level atom (ladder type) in a momentum eigenstate with a single mode cavity field in the presence of non-linearities of both the field and the intensity-dependent coupling. The constants of motion and the wave function for the atomic system have been obtained. Special attention is given to discuss some statistical aspects of the considered atomic system such as momentum increment, momentum diffusion and high-order squeezing. The influence of the Kerr-like medium and the intensity dependent coupling on the momentum increment and the high-order squeezing are investigated numerically. It is found that addition of these parameters has an important effect on both the momentum increment and the squeezing phenomenon.Proučavamo međudjelovanje četiri-razinskog atoma (poput ljestvi) u impulsnom svojstvenom stanju s jednomodnim poljem u rezonatoru, uz nelinearnosti polja i vezanja ovisnog o intenzitetu. Izveli smo stalnice gibanja valne funkcije atomskog sustava. Posebnu smo pažnju posvetili raspravi o statističkim odlikama razmatranog atomskog sustava, kao što su povećanje i difuzija impulsa i zbijanje višeg reda. Numerički smo istražili utjecaj Kerrovog sredstva i vezanja ovisnog o intenzitetu na povećanje impulsa i zbijanje višeg reda. Našli smo da dodavanje tih parametara ima snažan učinak na povećanje impulsa i pojavu zbijanja

Međudjelovanje četiri-razinskog atoma u impulsnom svojstvenom stanju s jednomodnim poljem

We study the interaction between a four-level atom (ladder type) in a momentum eigenstate with a single mode cavity field in the presence of non-linearities of both the field and the intensity-dependent coupling. The constants of motion and the wave function for the atomic system have been obtained. Special attention is given to discuss some statistical aspects of the considered atomic system such as momentum increment, momentum diffusion and high-order squeezing. The influence of the Kerr-like medium and the intensity dependent coupling on the momentum increment and the high-order squeezing are investigated numerically. It is found that addition of these parameters has an important effect on both the momentum increment and the squeezing phenomenon.Proučavamo međudjelovanje četiri-razinskog atoma (poput ljestvi) u impulsnom svojstvenom stanju s jednomodnim poljem u rezonatoru, uz nelinearnosti polja i vezanja ovisnog o intenzitetu. Izveli smo stalnice gibanja valne funkcije atomskog sustava. Posebnu smo pažnju posvetili raspravi o statističkim odlikama razmatranog atomskog sustava, kao što su povećanje i difuzija impulsa i zbijanje višeg reda. Numerički smo istražili utjecaj Kerrovog sredstva i vezanja ovisnog o intenzitetu na povećanje impulsa i zbijanje višeg reda. Našli smo da dodavanje tih parametara ima snažan učinak na povećanje impulsa i pojavu zbijanja

Isogeometric analysis for functionally graded microplates based on modified couple stress theory

Analysis of static bending, free vibration and buckling behaviours of functionally graded microplates is investigated in this study. The main idea is to use the isogeometric analysis in associated with novel four-variable refined plate theory and quasi-3D theory. More importantly, the modified couple stress theory with only one material length scale parameter is employed to effectively capture the size-dependent effects within the microplates. Meanwhile, the quasi-3D theory which is constructed from a novel seventh-order shear deformation refined plate theory with four unknowns is able to consider both shear deformations and thickness stretching effect without requiring shear correction factors. The NURBS-based isogeometric analysis is integrated to exactly describe the geometry and approximately calculate the unknown fields with higher-order derivative and continuity requirements. The convergence and verification show the validity and efficiency of this proposed computational approach in comparison with those existing in the literature. It is further applied to study the static bending, free vibration and buckling responses of rectangular and circular functionally graded microplates with various types of boundary conditions. A number of investigations are also conducted to illustrate the effects of the material length scale, material index, and length-to-thickness ratios on the responses of the microplates.Comment: 57 pages, 14 figures, 18 table

Nitrate removal from water using UV-M/S2O42- advanced reduction process

In this work, a new process called advanced reduction process (ARP) was used for nitrate removal from water. This ARP process combines sodium dithionite as reducing agent with ultraviolet irradiation using medium pressure lamps (UV-M) as an activating method. Experimental results showed that UV-M/S2O42- process achieved almost complete removal of nitrate from aqueous solutions containing 25 mg NO3-/L using stoichiometric dose of dithionite of 68.8 mg/L at neutral pH conditions. Analysis of final products and material balance confirmed that NO3- ions were reduced to ammonium with formation of nitrite as intermediates in addition to the formation of small amounts of volatile species, mainly ammonia and nitrogen gas. Effects of certain experimental parameters including dithionite dose, initial pH, initial nitrate concentration, and UV light source on the kinetics and efficiency of nitrate reduction were evaluated. Increasing dithionite dose augmented the rate of nitrate reduction and enhanced the efficiency of ARP process. Dithionite doses higher than stoichiometric ratios led to complete removal of nitrate in shorter reaction time. UV-M/S2O42- process was found to be effective only under neutral pH or alkaline conditions, and its removal efficiency is negligible in acidic medium (pH < 4). Irradiation with UV-M was more effective than low pressure or narrow band lamps. These results can be attributed to the contribution of several mechanisms for nitrate reduction to ammonium. These include the following: direct photolysis, chemical reduction of nitrate dithionite, and mediated reduction of nitrate by free reducing radicals. © 2013 Islamic Azad University (IAU).Qatar National Research Fund (QNRF) - No. NPRP 4-1174-2-458

Toward Improved Outcomes for Patients With Lung Cancer Globally: The Essential Role of Radiology and Nuclear Medicine

PURPOSE Key to achieving better population-based outcomes for patients with lung cancer is the improvement of medical imaging and nuclear medicine infrastructure globally. This paper aims to outline why and spark relevant health systems strengthening. METHODS The paper synthesizes the global lung cancer landscape, imaging referral guidelines (including resource-stratified ones), the reliance of TNM staging upon imaging, relevant multinational health technology assessments, and precisely how treatment selection and in turn patient outcomes hinge upon imaging findings. The final discussion presents data on current global gaps in both diagnostics (including imaging) and therapies and how, informed by such data, improved population-based outcomes are tangible through strategic planning. RESULTS Imaging findings are central to appropriate lung cancer patient management and can variably lead to life-prolonging interventions and/or to life-enhancing palliative measures. Early-stage lung cancer can be treated with curative intent but, unfortunately, most patients with lung cancer still present at advanced stages and many patients lack access to both diagnostics and therapies. Furthermore, half of lung cancer cases occur in low- and middle-income countries. The role of medical imaging and nuclear medicine in lung cancer management, as outlined herein, may help inform strategic planning. CONCLUSION Lung cancer is the number one cancer killer worldwide. The essential role that medical imaging and nuclear medicine play in early diagnosis and disease staging cannot be overstated, pivotal in selecting the many patients for whom measurably improved outcomes are attainable. Prevention synergized with patient-centered, compassionate, high-quality lung cancer management provision mandate that strategic population-based planning, including universal health coverage strategies, should extend well beyond the scope of disease prevention to include both curative and noncurative treatment options for the millions afflicted with lung cancer

Mutations in ASXL1 are associated with poor prognosis across the spectrum of malignant myeloid diseases

The ASXL1 gene is one of the most frequently mutated genes in malignant myeloid diseases. The ASXL1 protein belongs to protein complexes involved in the epigenetic regulation of gene expression. ASXL1 mutations are found in myeloproliferative neoplasms (MPN), myelodysplastic syndromes (MDS), chronic myelomonocytic leukemia (CMML) and acute myeloid leukemia (AML). They are generally associated with signs of aggressiveness and poor clinical outcome. Because of this, a systematic determination of ASXL1 mutational status in myeloid malignancies should help in prognosis assessment

Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis

Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel