ZIP3D: An elastic and elastic-plastic finite-element analysis program for cracked bodies

ZIP3D is an elastic and an elastic-plastic finite element program to analyze cracks in three dimensional solids. The program may also be used to analyze uncracked bodies or multi-body problems involving contacting surfaces. For crack problems, the program has several unique features including the calculation of mixed-mode strain energy release rates using the three dimensional virtual crack closure technique, the calculation of the J integral using the equivalent domain integral method, the capability to extend the crack front under monotonic or cyclic loading, and the capability to close or open the crack surfaces during cyclic loading. The theories behind the various aspects of the program are explained briefly. Line-by-line data preparation is presented. Input data and results for an elastic analysis of a surface crack in a plate and for an elastic-plastic analysis of a single-edge-crack-tension specimen are also presented

Three-dimensional elastic-plastic finite-element analyses of constraint variations in cracked bodies

Three-dimensional elastic-plastic (small-strain) finite-element analyses were used to study the stresses, deformations, and constraint variations around a straight-through crack in finite-thickness plates for an elastic-perfectly plastic material under monotonic and cyclic loading. Middle-crack tension specimens were analyzed for thicknesses ranging from 1.25 to 20 mm with various crack lengths. Three local constraint parameters, related to the normal, tangential, and hydrostatic stresses, showed similar variations along the crack front for a given thickness and applied stress level. Numerical analyses indicated that cyclic stress history and crack growth reduced the local constraint parameters in the interior of a plate, especially at high applied stress levels. A global constraint factor alpha(sub g) was defined to simulate three-dimensional effects in two-dimensional crack analyses. The global constraint factor was calculated as an average through-the-thickness value over the crack-front plastic region. Values of alpha(sub g) were found to be nearly independent of crack length and were related to the stress-intensity factor for a given thickness

Effect of fungal biosorbed and nonbiosorbed copper and zinc metal solutions on growth and metal uptake of leguminous plants

Effect of Zn, Cu and Cu + Zn at 10, 25, 50, 100, 200 and 500ppm concentrations of fungal untreated and treated metal solutions on seed germination and seedling vigor of Cicer areietinum (Chick pea), Macrotyloma uniflorum (Horse gram), Vigna radiata (Green gram) and Vigna unguiculata (Cowpea) were evaluated. Heavy metal solutions were prepared in increasing concentration up to the concentration critical to the soil. Increased metal concentrations reduced the seed germination and growth of test plants. Low metal concentrations of 10, 25, 50 ppm, stimulated the shoot, root and seed germination in test plants. Untreated and treated effluent was not acutely toxic to the seed germination and plant growth. In Aspergillus niger and Aspergillus flavus biosorbed metal ions, reduced metal toxicity with increased seedling vigor was observed. Efficiency of metal biosorption by fungal biomass and metal ions tolerance and accumulation ability in test plants were analyzed by Atomic Absorption Spectrophotometer (AAS).  Â

Design of a 1.9 GHz low-power LFSR circuit using the Reed-Solomon algorithm for Pseudo-Random Test Pattern Generation

A linear feedback shift register (LFSR) has been frequently used in the Built-in Self-Test (BIST) designs for the pseudo-random test pattern generation. The volume of the test patterns and test power dissipation are the key features in the large complex designs. The objective of this paper is to propose a new LFSR circuit based on the proposed Reed-Solomon (RS) algorithm. The RS algorithm is created by considering the factors of the maximum length test pattern with a minimum distance over the time. Also, it has achieved an effective generation of test patterns over a stage of complexity order O (m log2 m), where m denotes the total number of message bits. We analyzed our RS LFSR mathematically using the feedback polynomial function for an area-sensitive design. However, the bit-wise stages of the proposed RS LFSR are simulated using the TSMC 130 nm IC design tool in the Mentor Graphics platform. Experimental results showed that the proposed LFSR achieved the effective pseudo-random test patterns with a low-test power dissipation (25.13 µW). Ultimately, the circuit has operated in the highest operating frequency (1.9 GHz) environment.   &nbsp

A re-evaluation of finite-element models and stress-intensity factors for surface cracks emanating from stress concentrations

A re-evaluation of the 3-D finite-element models and methods used to analyze surface crack at stress concentrations is presented. Previous finite-element models used by Raju and Newman for surface and corner cracks at holes were shown to have ill-shaped elements at the intersection of the hole and crack boundaries. These ill-shaped elements tended to make the model too stiff and, hence, gave lower stress-intensity factors near the hole-crack intersection than models without these elements. Improved models, without these ill-shaped elements, were developed for a surface crack at a circular hole and at a semi-circular edge notch. Stress-intensity factors were calculated by both the nodal-force and virtual-crack-closure methods. Both methods and different models gave essentially the same results. Comparisons made between the previously developed stress-intensity factor equations and the results from the improved models agreed well except for configurations with large notch-radii-to-plate-thickness ratios. Stress-intensity factors for a semi-elliptical surface crack located at the center of a semi-circular edge notch in a plate subjected to remote tensile loadings were calculated using the improved models. The ratio of crack depth to crack length ranged form 0.4 to 2; the ratio of crack depth to plate thickness ranged from 0.2 to 0.8; and the ratio of notch radius to the plate thickness ranged from 1 to 3. The models had about 15,000 degrees-of-freedom. Stress-intensity factors were calculated by using the nodal-force method

Carrier shifting algorithms for the mitigation of circulating current in diode clamped MLI fed induction motor drive

Abstract: Reduction of circulating current is one of the major considerations in inverter fed electrical drives. Diode clamped MLI enables higher output current per phase, thereby rating of the drive gets increased effectively. Various methods of triggering in the inverter legs creates better voltage profile and leads to the enabling of circulating current in the drive system. The induced circulating current flows through the apparatus neutral (N) and supply ground (G) is caused by the existence of parasitic capacitance. This circulating current may cause potential danger especially when parasitic capacitance poses large. In the past, different modulation techniques and conversion topologies have been introduced to minimize the flow of circulating current. However, these techniques lead to complexity, high cost, low voltage profile and efficiency due to lower modulation parameters. This paper proposes PS, POD, PD carrier shifting PWM algorithms for diode clamped MLI to tumbling the circulating current within the each phase of inverter legs. The performances of proposed algorithm, in terms of circulating current, THD, losses and efficiencies are analyzed theoreticallyand are validated via simulation and experimental results

Sodium-glucose cotransporter 2 inhibitor effects on cardiovascular outcomes in chronic kidney disease

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce cardiovascular events, specifically those related to heart failure in patients with type 2 diabetes. Reductions in major adverse cardiovascular event (MACE) outcomes are also observed, but confined largely to patients who have prior cardiovascular disease. Cardiovascular outcome benefits extend to patients with type 2 diabetes and reduced estimated glomerular filtration (eGFR) rate down to 30 mL/min/1.73 m2 and to patients with heart failure but without diabetes. Ongoing trials are exploring whether patients with chronic kidney disease (CKD) but without diabetes will gain similar benefits from this class of agents. Although some safety concerns have emerged, it seems likely that SGLT2 inhibitors will be used more widely in CKD patients to reduce their cardiovascular risk

Mechanisms and Implications of Age-Related Changes in the Liver: Nonalcoholic Fatty Liver Disease in the Elderly

Nonalcoholic fatty liver disease (NAFLD) is hepatic steatosis associated with metabolic abnormalities such as overweight/central obesity, insulin resistance, type 2 diabetes (T2D), and dyslipidemia. NAFLD is becoming the most common liver disease in contemporary society, with the highest prevalence in those over 60 years. NAFLD pathology ranges from simple steatosis to a necroinflammatory fibrosing disorder called steatohepatitis (SH), the latter associated with high risk of developing cirrhosis, often occuring in the seventh to ninth decades of life. While the main health implications of NAFLD are increased risk of developing T2D, cardiovascular diseases, and common cancers, there is substantantially increased standardized mortality, and deaths from decompensated cirrhosis and hepatocellular carcinoma (HCC). Little is known about the interactive effects of ageing and NAFLD, with most studies focusing on the younger population. This paper summarises the epidemiology, pathogenesis, and clinical course of NAFLD, with particular attention to persons over age 60 years. An approach to the management of NASH and its complications in the elderly, will also be presented here

Investigational synthetic neuroactive steroid zuranolone in treatment of major depressive disorder with peripartum onset

Major depressive disorder with peripartum onset or peripartum depression is a common condition experienced by a large proportion of women and to some extent even in men. The current treatment strategies involve the use of conventional pharmacotherapeutic classes of drugs like selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs) and psychotherapy methods in the management of this condition. In this article, we try to review and evaluate the pathophysiology of the condition along with the safety and efficacy of the novel investigational therapeutic drug zuranolone, which is a synthetic neuroactive steroid (NAS) that has shown promise in clinical trials for the management of conditions like major depressive disorder, peripartum depression and bipolar disorder. The synthetic NAS zuranolone is an orally bioavailable positive allosteric modulator of the gamma amino butyric acid (GABAA) receptor, which can regulate the action of the GABAergic pathway implicated in many depressive episodes and also affect the normal functioning of the hypothalmo pituitary-adrenal (HPA) axis which is the core pathophysiological cause behind major depressive disorder with peripartum onset

Manurial value of byproducts of bio-diesel feed stocks on finger millet grain and dry fodder productivity

A replicated field experiment was conducted at Agricultural Research Station (ARS), Madenur located in Hassan District, Karnataka in rainy season during 2007 to assess the manurial value of by-products of bio-diesel feed stocks-pongamia and neem oil seed cakes vis-à-vis conventional plant nutrients sources (combination of farm yard manure and inorganic fertilizers) on the grain and fodder productivity of finger millet, the staple food cereal of southern Karnataka. Grain and dry fodder productivity of finger millet crop grown using pongamia and neem seedoil cakes is comparable to that grown using conventional plant nutrient sources. Application of plant nutrients only through pongamia and neem seed oil cakes resulted in higher available soil Nitrogen, Potassium and Organic Carbon contents