STRESS CONCENTRATION FACTOR Research Papers (original) (raw)

2025, FEA and Experimental Insights on S355 Steel Hydraulic Cylinders

This project presents a comprehensive structural analysis of S355 steel hydraulic cylinders, focusing on stress and strain distributions relevant to automotive lift applications. It employs an integrated methodology combining Finite... more

2025, Marine Pollution Bulletin

Mean concentrations of 137Cs and 4°K in harbour porpoise are presented. Concentrations of 137Cs in porpoises originating from the Irish Sea were elevated relative to those from the Celtic Sea, Atlantic seaboard and the North Sea. Concentrations of 4°K were comparable between samples from all locations and similar to those reported elsewhere. Concentration factors (CF) determined for Irish Sea porpoise did not differ significantly from those measured for other regions. The dose arising from 1L37Cs and 4°K was dominated by the internal component. As most of the total dose was attributable to the naturally occurring 4°K, it is unlikely that the increased dose due to the anthropogenic input of radionuclides has a detrimental effect on the health of Irish Sea porpoise. Elevated concentrations of 137Cs in porpoises from the Irish Sea suggest they may be resident in the area.

2025, Journal of the Optical Society of America A

Equation (30) of our paper' should read as follows: However, both expressions coincide for 0' = 0, so the conclusions given in our paper are correct.

2025

Statistical analysis reveals that mechanical damage is the first cause of incidents on gas transmission pipelines. They can be created by third party activities such as excavator tooth impact or by interaction between the pipe and rocks. To manage the damaged pipeline safely without useless cost, there is a need to investigate the mechanical behaviour of dented pipelines under a varying internal pressure. The purpose of this study is to characterize the stress and strain field around defects in pipes submitted to cyclic pressure loadings in order to estimate their residual lifetime. Full 3D finite element analyses of the denting process followed by cyclic loading are performed. Full-scale experiments on dented sections are planned.

2025, Computational Materials Science

The work presented in this paper utilises a numerical analysis for the computation of stress concentration factor generated by the presence in the weld nugget of a pore formed during the welding process. Welded structure containing porosity is subjected to uniaxial tensile stress. The effects of geometrical parameters of the pore and the interaction pore-defect on the stress concentration factor variation have been analyzed.

2025

This work measures the radiological content of liquid effluent discharged from a Nigerian Hospital that has a Department of Nuclear Medicine where diagnostic and therapeutic activities were carried out using medical radioisotopes. The main focus is to examine the management of radioactive biological waste from patients after undergoing radio-iodine therapy. This study was carried out for a period of 5 days. Samples of liquid effluent at the point of final discharge from the Hospital into the Municipal sewer system were collected on daily basis, within the hour after radioactive urine waste was discharged into the hospital sewer system. A G.M Tube detector was used in measuring the mean dose rates directly from the liquid effluent samples. The dose rates measured from the liquid effluent samples range from 0.13 to 0.20μSv/hr which was within similar range as the mean dose rate (0.20μSv/hr) from natural background radiation measured prior to the study at locations upstream of the hosp...

2025

The trend in the Danish society is toward disconnection of stormwater from the combined sewers and, where needed, local treatment using the best available technologies (BAT). The aim here was to assess a fast filtration technology for removal of particulate matter in stormwater with an emphasis on colloidal and nanosized particles. During the project period it rained 8.5% of the time and the average daily rainfall was 2.9 mm/day. Based on three individual storm events it was found that 95% of the particles were< 10 µm ...

2025, Revista de Ciências Ambientais

As características físico-químicas do solo refletem processos globais e locais que influenciam na distribuição das formações vegetais. Nesse estudo, foi investigada a existência de padrões físicoquímicos de solo associados às espécies arbóreas dos manguezais, por meio de análises físicoquímicas do solo nas espécies Rizhophora mangle, Laguncularia racemosa, Avicennia schaueriana e Conocarpus erectus. Posteriormente, foi realizada a Análise dos Componentes Principais, utilizando a correlação de Pearson. Os componentes principais em R. mangle foram a capacidade de troca catiônica, soma das bases e argila; em L. racemosa, o hidrogênio, areia grossa e magnésio; em A. schaueriana, a capacidade de troca catiônica, fósforo e silte; em C. erectus, o potássio, cálcio e areia grossa. Os resultados sugerem padrões físico-químicos do solo nas espécies. Rizhophora mangle e A. schaueriana exibiram características físicas do solo semelhantes e atributos químicos distintos, do mesmo modo que L. racemosa e C. erectus. A disponibilidade de nutrientes e a capacidade de troca catiônica foram significativas para R. mangle e A. schaueriana, o pH, para L. racemosa e a composição granulométrica para C. erectus, sugerindo um padrão físico-químico do solo.

2025, Universidade Federal do Espírito Santo

Aos meus pais, pelo exemplo. Aos meus irmãos Angela e Marcelo, pelo carinho, força e estímulo. À minha tia Deuziana, que foi quem começou tudo isso. Ao Irineu pelo apoio emocional, paciência e força nos momentos difíceis. Ao Prof. Geraldo Rogério Faustini Cuzzuol pela compreensão e brilhante orientação. À Suzano Papel e Celulose -Unidade Mucuri, pela cessão dos dados de nutrientes e granulometria do manguezal do Rio Mucuri. Ao CEPEMAR -Serviços de Consultoria em Meio Ambiente Ltda, na pessoa do amigo Renato Rodrigues de Souza, pela logística de campo. Ao querido amigo e companheiro de trabalho Emerson Campos Canal que foi mais do que um irmão, nas horas difíceis de campo e laboratório. Ao Prof. Dr. Luis Fernando Ganassali Júnior pelas excelentes contribuições na parte estatística, pelo apoio e a atenção dedicados. Aos Profs. Drs. Camila Milanêz e Fabrício Oliveira Reis pela disponibilidade em todos os momentos. Aos colegas da pós-graduação, pela convivência sempre saudável. Aos colegas Queila Bravo, Jehová Lourenço, Maressa Malini e Natália pela colaboração. À Clara Maria Dalto Franzotti pela leitura e revisão ortográfica deste documento. Aos primos Rafael Gomes Bastos e Gabriel Gomes Bastos pela leitura e revisão dos abstracts deste documento. À Universidade Federal do Espírito Santo, especialmente ao Departamento de Ciências Biológicas, pela oportunidade concedida para a realização deste curso. A todos aqueles que criaram barreiras à execução deste trabalho pois, é sempre nas dificuldades que a gente se supera. A todos que, direta ou indiretamente, contribuíram para a realização deste trabalho.

2025, Earth and Planetary Science Letters

Isotopes (Nd, Sr and Pb) and trace elements (REE, Ba, Sr, Rb) have been measured on a set of basaltic glasses from a restricted area (40 X 10 km) at 12OSO'N on the East Pacific Rise. The huge variation of incompatible element concentrations (factor 70 for Ba concentrations), and the variable degrees of correlation between element concentrations cannot be explained by usual models of melting and fractional crystallization. A rough correlation between the Ce/Yb ratio and the isotopic ratios favors a "source effect" for the genesis of the glasses. We have developed a model including both partial melting process acting on a heterogeneous mantle source with two components (peridotites and pyroxenites; "marble cake mantle" of ABegre and Turcotte) and fractional crystallization. The purpose of this model is not to obtain values of the four parameters involved (degree of melting in the peridotites, in the pyroxenites, proportion of pyroxenites involved in the melting, degree. of fractional crystallization) for each analyzed glass, but to model the whole set of glasses by stochastic genesis and sampling of liquids. We have used the stochastic procedure for the four controlled parameters, currently generating 10,000 "samples". Our preferred model for this portion of the East Pacific Ridge is obtained with a degree of melting in the peridotites and in the pyroxenites varying uniformly from 6 to 208, and from 6 to 50% respectively. The degree of mixing between liquids issued from the two sources varies from 0 to lOO'%, and the degree of fractional crystallization remains small, without noticeable effect on the concentrations, varying from 0 to 6%.

2025, Journal of Materials Science - J MATER SCI

A zero-order model is presented, which allows calculation of the stress distribution in porous epoxies by taking into account the interaction between randomly distributed voids. These results demonstrate that the mean value of the stress concentration factor increases with the volume fraction of voids. This leads to a decrease in sample yield strength. However, the generation of a porous morphology also creates a considerable number of regions where the stress is completely released. The theoretical predictions are in good agreement with experimental results obtained with macroporous epoxies, which were prepared based on the chemically induced phase separation technique, and tested under uniaxial compression.

2025, Sensors and Actuators A: Physical

A micro-preconcentrator unit has been fabricated on silicon technology. The unit consists of a 3D-microheater surrounded by an insulating membrane. The preconcentrator is made up of a grid of suspended silicon bars underneath a polysilicon resistor. The grid was formed by 40-m wide, 520-m depth, 3000-m long silicon bars fabricated by deep reactive ion etching covering a 3 mm × 3 mm area. This type of silicon grid structure allows to hold large amount of absorbent materials and provides efficient heat diffusion. The dimensions of the -preconcentrator were defined to achieve good thermal isolation and high absorbent content to yield a high gas concentration factor. Thermal characterization of the heater showed a low heat capacity of the structure and therefore, fast response and high power efficiency.

2025, Environmental Science & Technology

We examined the bioavailability of colloid-bound metals [Cd, Cr(III), and Zn] to two marine bivalves (mussel Perna viridis and clam Ruditapes philippinarum) from subtropical and tropical waters. Natural colloids (between 1 nm and 0.2 µm) were isolated by cross-flow ultrafiltration. Bivalves were then exposed to radiolabeled colloids, and the uptake of colloid-bound metals was compared with the uptake of metals associated with the low molecular weight fraction (LMW, <1 kDa). In general, the bioavailability of colloidbound Zn to mussels was significantly inhibited as compared to that of the LMW-bound Zn. Its uptake decreased with increasing colloidal organic carbon (COC) concentration. There was no major difference in Cd bioavailability between the LMW and the colloidal treatments, primarily because most of the radiolabeled colloidal Cd remained in the truly dissolved phase during the uptake period. In contrast, the bioavailability of colloid-bound Cr was enhanced in the mussels. In clams, bioavailability of metals was not significantly influenced by colloidal binding, although Zn uptake was slightly enhanced when it was associated with the LMW fraction. The measured dry weight concentration factor (DCF) in bivalve tissue was the highest for Zn, followed by Cd and Cr. Furthermore, DCF was higher in the mussels (20-340) than in the clams (10-35). Colloidbound metals were mostly accumulated in mussel digestive gland and remaining soft tissue (64-87%), whereas a large fraction (36-73%) of metals was found on the shell of the clams. Coagulation of radioactive tagged colloidal organic matter was insignificant (<9%) for metals in the absence of large suspended particles, indicating that coagulation effects on metal uptake were minimal under our experimental conditions. Thus, our study demonstrated that colloid-bound metals were bioavailable to both the mussels and the clams, but the influences of colloidal binding on metal uptake varied among metals and between the two bivalves.

2025, Analytica Chimica Acta

Among several methods, enrichment techniques based on sorption onto chelating resins seem convenient, rapid and capable to achieve a high concentration factor. Amberlite IRA-904 resin modified with tetrakis (p-carboxyphenyl) porphyrin (TCPP) was used to pre-concentrate vanadium species. Several parameters, such as sorption capacity of the chelating resin, pH for retention of V(IV) and V(V), volume of sample and eluent, were evaluated. Both vanadium species sorbed on TCPP-modified resin were eluted by use of 2 M nitric acid and determined by atomic absorption spectrometry. The recovery values were >94% and pre-concentration factor of 110 was obtained. For speciation studies, CDTA was added to the sample for complexing vanadium(IV), which was not retained on the microcolumn. The proposed method was examined for reference standard material (TM-25.2) and river water sample.

2025

Offshore structures are fabricated from tubes or circular hollow sections. Tubular joints which are created at the intersection of the circular members experience complicated structural problems such as stress concentration, ultimate strength, joint stiffness and fatigue life. S o m e aspects of tubular T-joints regarding joint stiffness and stress concentration are This work could not have been completed without the support of a number of people to w h o m I a m deeply grateful: Dr Richard Kohoutek, m y supervisor, whose guidance was constructive in maintaining a proper direction towards the completion of this thesis. M r Ian Bridge, a professional technician, w h o fabricated the test specimens and related hardware. Mr. Charles Mitchell and Tino Ferrero for their assistance in carrying out the experiments. Other members of technical staff in the Department of Civil and Mining Engineering especially M s . Lyn Middleton for proof reading of m y thesis, and M r . Richard W e b b for his general assistance in the laboratory. Mrs. J. Kohoutek for drawing the sketches of the test specimens. I wish to thank m y wife, Mahbobeh, for her unending patience and understanding through all the difficulties w e encountered when this work was being carried out. Iraj Hoshyari, August 1993 viii 3.5 B e a m model for definition of rigidity factor (unit length) 50 3.6 Relationship between rotational stiffness and beam end flexibility 51 3.7 Axially loaded member with semi-rigid ends 3.8 Relationship between axial stiffness and axial end flexibility 54 4.1 Distribution of f$ parameter for T-joints. The survey was carried out by UEG (1985) on six offshore structures 4.2 Distribution of y parameter for T-joints. The survey was carried out by U E G (1985) on six offshore structures 4.3 Distribution of y parameter for T-joints. The survey was carried out on the database in U E G (1985) 4.4 Distribution of P parameter for T-joints. The survey was carried out on the database in U E G (1985) 4.5 Distribution of T parameter for T-joints. The survey was carried out on the database in U E G (1985) 4.6 A typical weld cross section of a T-joint specimen 60 4.7 Diagrammatic test set-up for frequency measurement of T-joints (IPB) 61 4.9 Typical frequency spectrum of a tubular T-joint 4.10 Lumped mass model used to establish the mode shapes of joints 4.11 First two mode shapes of T-joint T10 from Dynamic Modal Analysis 65 4.12 Relationship between natural frequencies of specimens and diameter ratio 66 4.13 Stiffness calculation of a T-joint using measured natural frequency 67 4.14 Analytical model used for rigidity calculation of tested T-joints (TPB) 68 4.15 Support arrangement for inplane bending test

2025

Milk is considered as a nutritional and healthy food product. Physicochemical analysis and microbiological analysis of milk and traditional cheeses are important points in evaluating the quality of products. This study investigates the physicochemical composition and microbiological safety of milk and cheese from cows, goats, and sheep, focusing on key pathogens, including Listeria monocytogenes and Staphylococcus aureus. A total of 21 cheese samples from different farms across different regions were collected for milk quality assessment. Milk is analyzed also from goats, sheep and cows as an initial product of cheese. Analyses of physical and chemical parameters such as protein, fat, dry matter, acidity and pH as well as analyses of the Staphylococcus aureus and Escherichia coli were performed by using traditional methods for milk and cheese. Result shows that, all pathogen levels were below international ISO standards, confirming the safety of these dairy products. The analysis revealed notable differences across milk types: cows' milk displayed the highest titratable acidity (7.01 °SH), while sheep's milk was the richest in protein (5.01 g•100 g⁻¹) and fat content was the highest in sheep (6.03 g•100 g⁻¹) compared to cows and goats. Additionally, the study examined cheeses derived from these milk types, observing variations in pH, salt, and nutrient profiles, influenced by local farming practices. These findings underline the importance of standardizing dairy production to ensure consistent quality and safety, providing valuable insights for producers, nutritionists, and policymakers within Kosovo's dairy industry.

2025

Fatigue life estimation is of high importance during the design stage of a machine or component. Basic fatigue calculations are made based on the use of an S-N curve. As far as constant amplitude loads are applied, this approach works well. However, most part of components in service are subjected to a variable amplitude load spectrum. In this case, linear approaches for fatigue life estimation can lead to over conservative results, which in other words means a heavier and more expensive machine. To further investigate the effect of (complex) service spectra (measured or statistically calculated), simpler load variations must be studied. This paper aims to show the general trend of these events and suggest the underlying physical phenomena behind load and interaction effects. As it will be highlighted, overloads are frequent in a spectrum and they are believed to be responsible for retardation effects. The plasticity induced crack closure mechanism is the most profound explanation f...

2025

A hybrid global-local methodology to predict fatigue crack path and propagation life in 2D structures is extended to model crack retardation effects induced by variable-amplitude (VA) loading histories. First, finite element (FE) models are used at each propagation step to calculate the generally curved fatigue crack path. However, the FE approach alone is not computationally efficient to predict crack growth rate, because it would require time-consuming remeshing of the entire structure after each event in VA loading. Therefore, the crack path and their mixed-mode stress intensity factors are FE calculated under constant-amplitude (CA) loading using fixed crack increments, requiring only relatively few remeshing steps. An analytical expression is then fitted to the calculated K I values, which is used in a powerful general purpose local-approach fatigue design program to predict crack propagation lives under VA loading, considering load interaction effects such as crack retardation or arrest after overloads. This methodology is experimentally validated by fatigue crack growth tests on compact tension C(T) specimens, modified with holes positioned to attract or to deflect the fatigue cracks. Experiments under VA loading are also performed on C(T) specimens without holes. Several crack retardation models are calibrated based on straight-crack data. These models are then used to successfully predict the curved crack growth behavior under VA loading of the hole-modified specimens.

2024, Ocean Engineering

A reasonably accurate estimate of fatigue reliability is considered to be essential for offshore structures due to their high construction cost and failure consequences. In the present paper, firstly, a fracture mechanics based fatigue limit-state function is derived and effects of assigning different values to deterministic variables involved in this limit-state function on the results of reliability analysis are investigated. These deterministic variables are the material parameter, number of stress cycles, and the mean value of critical crack size. Afterwards, effects of stress concentration factors (SCFs) on the reliability of the tubular joint are studied. The SCF is one of the most important parameters in the fatigue reliability analysis, which exhibits considerable scatter. Results showed that change of the mean value of SCF, from the value typically assumed in the previous research works (¼ 2.5) to a realistic value obtained in the present research for a widely used multi-planar joint ($ 15), leads to considerable decrease in the reliability index and consequently significant increase in the probability of failure. However, change of the coefficient of variation (CoV) of SCFs, from the typically assumed value (¼ 0.15) to a realistic value obtained in the present research ( $ 1.048), does not considerably affect the results.

2024, Metallurgical and Materials Transactions A

FIBERFRAX** (48Al 2 O 3 52SiO 2 ). [14] **FIBERFRAX is a trademark of Standard Oil Engineered Materials Co., Niagara Falls, NY.

2024

Cesium-137 is an anthropogenic radionuclide introduced in the environment in the early of 1960s to the end of 1970s. The Cesium-137 has very used to assess soil redistribution in the landscape because this is very tight in the fine soil particles and its movement in the landscape is due to soil redistribution. To use Cesium-137 to assess soil redistribution is need to known the Cesium-137 inventory in an area that not has experimented soil erosion neither soil deposition. So, this work present Cesium-137 inventories in undisturbed areas in different regions of Brazil, from South to Northeast of Brazil. The inventories in these areas represent the variational deposition of Cesium-137 in the whole national territory of Brazil. The inventories of Cesium-137 varied from 200 ± 15 Bq.m -2 for South region to 15 ± 2 Bq.m -2 for Northeast region. Moreover, was verified that the Cesium-137 inventories depend on latitude and altitude of the area.

2024

A mathematical model was developed to estimate the bioconcentration factor (BCF) of herbicides in sugarcane juice. The model correlates the BCF of herbicides with a) water transpiration rate (Q); b) transpiration steam concentration factor of the herbicides (TSCF); c) partition coefficient of plantwater of the herbicides (K PW); d) plant fresh weight (M); e) metabolic and dilution rate of the herbicide in the plant (k E and k G) and f) the herbicide soil degradation rate (k S). The selected herbicides for the study are approved to be used in sugarcane for weed control. The model simulates herbicide uptake by transpiration flow and water uptake in sugarcane applied to a hypothetic crop grow and development. The herbicides selected were 2,4-D, acetochlor, ametryn, atrazine, clomazone, diuron, hexazinone, imazapic, imazapyr, isoxaflutole, metribuzin, pendimethalin, picloram, simazine, sulfentrazone, tebuthiuron and trifluralin. The model fitness was evaluated through the sensitivity analysis of the herbicide BCF values in sugarcane juice with respect to the model entry data variability.

2024

This work is intended to propose a generic organization of classes, in the context of the Object-Oriented Programming (OOP) paradigm, to perform structural analyses of frame and truss models considering both dynamic and geometrically... more

2024, 2004 Solid-State, Actuators, and Microsystems Workshop Technical Digest

This work is part of the Cascade Avalanche Sorbant Plate ARray (CASPAR) project whose goals are the development of flow through preconcentrators that may be stacked into multiple planes for enhanced performance. These devices act as the front end of a portable Ion Mobility Spectrometer (IMS) for the detection of trace explosive or chemical agent vapors. We report on the design, simulation, fabrication and performance of 7mm x 7mm polyimide preconcentrators. The devices are composed of dual serpentine platinum heaters supported by a 3-6 µm thick layer of polyimide suspended over a silicon frame. Early prototypes have demonstrated an order of magnitude improvement in detection threshold for a single plane when tested with a commercial portable explosive detector.

2024, Engineering Structures

Past experience has shown that stringer-to-cross-girder connections in riveted railway bridges are susceptible to fatigue cracking. This fatigue damage is caused by secondary stresses, which develop in the different components of the connection. For this reason, more detailed analysis techniques are needed to capture this type of behaviour. In this paper, a finite element (FE) model of a typical riveted railway bridge is developed by incorporating the detailed local geometry of a stringer-to-cross-girder connection into the global bridge model. Prior to the development of this model, benchmark FE studies are carried out on a double-lap joint and the results are presented in terms of stress concentration factors and stress gradients. Further verification studies are carried out on a local bridge connection FE model, in terms of its rotational stiffness. Following this investigation, a refined FE model of the bridge is analysed under the passage of a freight train. Principal stress histories at different components of the connection are obtained, which are then combined with the plain material S-N curve, in order to identify the most fatigue-critical locations of the connection. These are identified as being the rivet holes and, in some cases, the angle fillet. By considering different rivet clamping stresses and different rivet defect scenarios it is found that the most damaging effects are caused by the presence of clearance between the rivet shank and the hole, and the loss of a rivet. The rivet clamping stress is also found to affect fatigue damage considerably.

2024, Desalination and Water Treatment

Acerola is a tropical fruit with a high antioxidant activity which may be attributed to its high vitamin C and anthocyanins content. The aim of this work was to produce a high quality concentrated acerola juice by an integrated membrane process, alternative to thermal evaporation. Acerola juice was clarifi ed by the microfi ltration process. The clarifi ed juice was preconcentrated by reverse osmosis process up to a total soluble solid content (TSS) of 28° Brix and after that the osmotic evaporation process (OE) was used to reach a TSS up to 55° Brix, corresponding to a concentration factor of 1.93. The vitamin C, anthocyanins content and antioxidant activity increased, respectively, 2.21, 1.41 and 2.28 folds in relation to the pre-concentrated juice when the OE was performed. The results showed that there was no change on the vitamin C content and antioxidant activity of the juice after its processing. However, it was verifi ed a reduction on the anthocyanins content, probably due to the great instability on this pigment. The obtained results showed that the integrated membrane process may be used as an alternative to obtain high quality concentrated juice, as the fi nal product still showed a very high antioxidant activity and a very high amount of vitamin C.

2024, Alexandria Science Exchange Journal /Alexandria Science Exchange journal

The present investigation was conducted to study the effect of partial substitution of UF-retentate of skimmed cow's milk with the denatured salt whey protein past (DSWPP) aiming to obtain the optimal formulation of the two ingredients for manufacturing of feta cheese analogue. In this study, the ratios of substitution were 5, 10, 15 and 20% (wt/wt). Physicochemical properties, texture profile, organoleptic properties, microbial quality and economic efficiency of the UF-FCA were studied along 60 days of refrigeration storage (6±2°C). Inclusion of DSWPP caused significant differences (p≤0.05) in physicochemical properties of UF-FCA. Dry matter content and pH values were decreased, while significant increase was observed in total protein, water soluble nitrogen, and titratable acidity values as compared to control. Moreover, significant differences were observed in texture parameters among all UF-FCA treatments. The values of hardness, springiness, cohesiveness, gumminess and chewiness were decreased, whereas adhesiveness values were increased as compared to control. Organoleptic properties of UF-FCA with or without DSWPP were acceptable by the panelists. Cheese samples contained 15% DSWPP were the most preferred among all treatments. The microbial quality was satisfactory for all cheese treatments. The cold storage for 60 days led to different changes in UF-FCA properties. The economic study efficiency indicates that the additional ratio of DSWPP up to 20% (wt/wt) as partial replacer for UF-skim milk retentate in the production of UF-FCA resulted in a decrease in the total production cost.

2024, International Journal for Research in Applied Science and Engineering Technology

2024, Mechanics

In this paper, the application requirement of the Residual Property Model based on the decrescent exponential function is reduced to only one mechanical test data. For this, by using Creager and Paris's elastic stress field equation in front of the blunt elliptical hole, the theoretical radius was chosen for the tip curvative and the maximum stress in the load direction at the tip is ensured to be equal the fracture toughness. Thus, the workload of the model is reduced by making the u exponent in the e-u function dependent on the geometric correction factor and the crack length. It was applied to the laminated composite specimens with three-point bending and the specimens including circular hole, and critical fracture stress values close to actual values were achieved.

2024

Geometrical discontinuities resulting from localized pitting can lead to substantial degradation of mechanical properties of steel structures especially in marine environments. This effect is usually evaluated in terms of the reduced section thickness associated with pit geometry which lowers the load carrying capacity of the structure. In this research, the effects of depth, spacing, and distribution of artificially produced, pit like, discontinuities on tensile ductility and fracture behavior of a structural steel have been investigated. Simulated pit distributions were produced on the gage sections of flat tensile specimens using mechanical drilling. A series of tensile tests were performed on specimens with pit area percents from 4 to 64% and various pith depths and spacing. It was found that fracture strain was substantially reduced at low pit area percents, but tended to partially recover at high pit area percents. This effect was further intensified by increasing pith depth. Furthermore, a change in the fracture surface orientation and formation of multiple secondary cracks were noted in pit distributions with higher stress concentration factors. SEM fractographs are presented to characterize the fracture surface morphologies. The overall findings are discussed in terms of mutual interaction of multiple stress concentration sites, triaxial stress state, and strain localization.

2024

The article discusses the derivation of a formula that links three constants that characterize the elastic properties of an isotropic elastic solid. In contrast to the known derivations in the literature [1], [ 2], a derivation based on the strain tensor is presented. It is shown that the off-diagonal element of the strain tensor is equal to half the angle of change of the right angle.

2024, IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

The recent emergence of lab-on-a-chip (LoC) technology has led to a paradigm shift in many healthcare-related application areas, e.g., point-of-care clinical diagnostics, highthroughput sequencing, and proteomics. A promising category of LoCs is digital microfluidic (DMF)-based biochips, in which nanoliter-volume fluid droplets are manipulated on a 2-D electrode array. A key challenge in designing such chips and mapping lab-bench protocols to a LoC is to carry out the dilution process of biochemical samples efficiently. As an optimization and automation technique, we present a dilution/mixing algorithm that significantly reduces the production of waste droplets. This algorithm takes O(n) time to compute at most n sequential mix/split operations required to achieve any given target concentration with an error in concentration factor less than 1 2 n. To implement the algorithm, we design an architectural layout of a DMF-based LoC consisting of two O(n)-size rotary mixers and O(n) storage electrodes. Simulation results show that the proposed technique always yields nonnegative savings in the number of waste droplets and also in the total number of input droplets compared to earlier methods. Index Terms-Biochips, computer-aided-design, digital microfluidics (DMFs), dilution of biosamples, mixing algorithms, waste minimization. I. Introduction T O MEET the challenges of healthcare cost for cardiovascular diseases, cancer, diabetes, global HIV crisis, and so on, a new field of interdisciplinary research centered around "lab-on-a-chip (LoC)" is emerging [1]-[5]. Typically, a LoC implements one or more biochemical laboratory protocols or assays on a single chip that is a few square centimeters in size.

2024, Solar Energy Materials and Solar Cells

This material may be reproduced by or for the U.S. Government pursuant to the copyright license under the clause at DFARS 252.227-7013 (NOV 95). The Institute for Defense Analyses is a non-profit corporation that operates three federally funded research and development centers to provide objective analyses of national security issues, particularly those requiring scientific and technical expertise, and conduct related research on other national challenges.

2024, Desalination and Water Treatment

Possibility of removal of textile dye from wastewater by extraction in aqueous two-phase system (ATPS) was studied in model solution of Acid blue 9. Partitioning of the dye in ATPSs composed of polyethylene glycol of different molecular weights (1,500, 6,000, and 10,000 g/mol) and several salts (ammonium sulfate, sodium sulfate, and sodium citrate) was investigated. Best results in respect of partitioning coefficient and concentration factor were obtained in polyethylene glycol 1,500/sodium citrate and polyethylene glycol 6,000/sodium citrate systems, respectively. Moreover, in selected ATPSs, the effect of tie-line length and volume ratio on partitioning parameters of Acid blue 9 was evaluated in order to determine conditions at which the highest possible removal of textile dye from wastewater could be achieved.

2024, Journal of Elasticity

As a sequel to a recent work we consider the generalized stress concentration factor, a purely geometric property of a body that for the various loadings, indicates the ratio between the maximum of the optimal stress and maximum of the loading fields. The optimal stress concentration factor pertains to a stress field that satisfies the principle of virtual work and for which the stress concentration factor is minimal. Unlike the previous work, we require that the external loading be equilibrated and that the stress field be a symmetric tensor field.

2024

The application of Ultrasonic Impact Treatment (UIT) to signal mast arms in the field is described. UIT has been demonstrated in the laboratory to provide a simple means to improve the fatigue performance of the fillet weld of connection of the mast arm tube to the end plate. The procedures used in the field are detailed and the time required for a repair documented. A fatigue test of a mast arm treated in the field is presented. The fatigue test indicated that the UIT treatment improved the performance of the connection to the level of a connection with a thicker end plate. UIT provides a cost effective means of increasing the service life of the mast arms at intersections where galloping oscillations of the mast arms have been observed.

2024

2024, Talanta

The utility of multivariate optimization methods in the determination of aqueous photolysis rates of organic compounds is examined in this study. A basic pursue was to designate the appropriate experimental design plan that extend the analytical utility of multivariate methods from qualitative data interpretation approaches, as applied thus far, to quantitative estimation methods. A three-level second-order central composite design with parameter concentrations (factor levels) beyond the environmental realistic concentrations was employed for that purpose enabling statistically significant effects to be determined. Method application is demonstrated in the first photodegradation study of two UV absorbing chemicals in natural waters. The results suggest that the proposed approach of enables a good approximation of the real behavior in terms of both qualitative and quantitative data interpretation with minimal loss of information.

2024, International Journal of Fatigue

This work is concerned with the consequences of switching the uniformly loaded end, and accordingly the supported end, that is, exchanging boundary conditions in shouldered shafts with fillet radius, subjected to uniform tension, on the resulting stress concentration factor magnitudes when the length of the member is taken into account. Notably different values of the stated factors result under the conditions of the study reported herein. An issue of importance is the reliability of design and analyses involving fatigue of mechanical and structural members. Transition length values from long to short length regimes are reported as well.

2024

The concentrations and spatial distribution of thirteen polycyclic aromatic hydrocarbons from٦ soil have been investigated in four regions locate in Al-Diwaniya city, Iraq. Sechelt extractions is used to extract PAHs compounds from all samples, gas chromatography was used to determine the PAHs concentration in all samples. The total concentrations of thirteen PAHs were ranged from 4.46ng.g-1 in site one to 17.24 ng.g-1 in site three of dry weight. The PAHs compounds those consist of four to six fused aromatic rings represent the majority among other PAHs in soil samples.

2024, Journal of Solid Mechanics

In this paper, accumulation of plastic deformation of AISI 1045 steel plates with circular cutouts under cyclic axial loading is studied. Loading was applied under force-control conditions. Experimental tests were performed using a Zwick/Roell servo hydraulic machine. Under force-control loading with nonzero mean force, plastic strain was accumulated in continuous cycles called ratcheting. Numerical analysis was carried out by ABAQUS software using nonlinear isotropic/kinematic hardening model. The results of the numerical simulations were compared to experimental data. The results demonstrated that the ratcheting response of plates with circular cutouts could be numerically simulated with a reasonable accuracy. It was observed that the local and global plastic deformation increase with increasing the notch diameter. Also, maximum principal stress was the main parameter for initiation of crack around the notch. Based on numerical results, at notch root, both ratcheting strain and local mean stress relaxation was occur simultaneously and due to relaxation of local mean stress, plastic shakedown was occurred.

2024, International Journal of Engineering Trends and Technology

The aim of this study was to investigate the impact of shape on cross-bored compound cylinders, particularly circular and elliptical configurations. The analysis was conducted with a uniform pressure of 88.494 MPa. It was found that a radial circular cross-bore with a cross-bore size ratio of 0.1 resulted in the lowest Stress Concentration Factor (SCF) of 2.66. Subsequently, a thorough examination of 12 different diameter ratios for the elliptical-shaped cross bore, ranging from 0.5 to 10, identified the minimum SCF value of 1.33, which occurred at a diameter ratio that was then used for further analysis. The mentioned SCF value represented a 24.81% reduction in the pressure-carrying capacity of the compound cylinder compared to a similar plain compound cylinder. In a broader comparison between circular and elliptical cross bores yielded lower hoop stresses than their circular counterparts.