Mechanisms for Introduction of Pseudo Ductility in Fiber Reinforced Polymer Composites- A Review

Advanced polymer matrix composites are gaining the market in their way due to their exceptional specific stiffness, specific strength, fatigue, and corrosion resistance in the field of Auto-Tech, Aero-Tech, Biotech, etc. However, the lack of ductility and catastrophic failure has limited their application in these areas. Hence there is a need to explore means and protocols for designing the reduced factor of safety with high-performance toughened composites. To address this problem, a new generation of high-performance composites with pseudo-ductile or ductile behavior is needed. The ongoing High-Performance Ductile Composite Technology (HiPerDuCT) program jointly between the University of Bristol U.K and Imperial College London to address this challenge by developing newer materials. The fiber architectures made under this project gave a more gradual failure rather than catastrophic failure which improves the mechanical properties. This paper mainly focuses on addressing this evolution of pseudo ductility in fiber-reinforced composites. In addition to this, an attempt has been made to newer possible fiber positions in matrix materials for inducing reasonable ductility in composites

Distress to Structures on Loose Ash and Cinder Fills

The Logan Section of the City of Philadelphia, that encompasses 17 city blocks and includes 997 row type dwellings, was constructed in the early 1900s. It is reported that settlement of these structures has continued since their construction. In 1986, a Geotechnical Investigation, commissioned by the City of Philadelphia, revealed that a total of two to three feet of settlement, with as much as one to two feet of differential settlement, has taken place. Recent measurements indicated that settlement is still in progress. This settlement has resulted in severe structural damage and, in some cases, collapse of the buildings. One hundred (100) homes have been declared imminently dangerous, 110 homes have been declared dangerous, and the remaining homes are considered moderately damaged. This paper discusses the probable causes of settlement, and evaluates the geotechnical characteristics and properties of the ash and cinders. These characteristics are considered the prime cause of the problem at the Logan Section

Analyse des systèmes piscicoles dans la Vallée du Niger (Nord Bénin)

L’objectif de cette étude était de diagnostiquer les systèmes piscicoles dans la Vallée du Niger. Ainsi, 119 Unités Villageoises de Pisciculture ont été recensées et enquêtées dans la zone d’étude. Cette étude a permis d’identifier trois techniques piscicoles relevant soit des systèmes extensifs pratiqués dans les trous à poissons, ou des systèmes semi intensifs de production pratiqués dans les étangs non vidangeables et vidangeables. Le Test T montre une différence significative de production selon les milieux d’élevage. La production des trous à poissons est estimée à 64,5 t/ha, soit trois fois meilleure à celle enregistrée dans les étangs non vidangeables (21,1 t/ha/an) et vidangeables (22,2 t/ha). Dans les deux types d’étangs, les productions ne sont pas significativement différentes. 11 espèces de poissons sont rencontrées dans les captures des pêcheurs. Les Claridae, Clarias gariepinus et Heterobranchus longifilis, représentent 80% des captures. Sur le plan sociologique, la pisciculture est pratiquée par des individus âgés de 20 à 65 ans. 3 groupes ethniques sont directement impliqués : Dendi (93,3%), Peulh (3,3%) et Fon (3,3%). Il ressort de notre étude que les trous à poissons sont très productifs et méritent donc d’être améliorés et généralisés pour la production piscicole dans la Vallée du Niger.Mots clés: Vallée du Niger, pisciculture, production, trous à poissons, étan

SPECTROPHOTOMETRIC DETERMINATION OF OXYBUTININE HYDROCHLORIDE BY ION-PAIR EXTRACTIONIN IN PHARMACEUTICAL PREPARATIONS

Objective: Simple, sensitive, precise, reproducible and validated visible spectrophotometric methods have been developed for the determination of an antimuscarinic drug, namely oxybutynin hydrochloride (OXB) in pure form and in pharmaceutical preparations.Methods: Two spectrophotometric methods are based on the formation of yellow colored ion-pair complexes between the studied drug, and two sulphonphthalein acid dyes, bromocresol purple (BCP) and bromophenol blue (BPB) with absorption maxima at 410 and 416 nm, respectively.Results: The stoichiometric ratio of the formed ion-pair complexes was found to be 1:1 (drug: reagent) for both methods as deduced by Job's method of continuous variation. Several parameters such as pH, buffer type, and reagent volume, sequence of addition and effect of extracting solvent were optimized to achieve high sensitivity, stability, low blank reading and reproducible results. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9996-0.9999) were found between the absorbance's and the concentrations of oxybutynin over the concentration ranges of 1.0–8.0 μg ml-1 and 1.0–12 μg ml-1 with LOD of 0.21 and 0.19 μg ml-1, using BCP and BPB methods, respectively. Various analytical parameters have been evaluated and the results have been validated by statistical data.Conclusion: The proposed methods were validated in accordance with ICH guidelines and successfully applied to the analysis of pharmaceutical formulation. Statistical comparison of the results obtained by applying the proposed methods with those of the reference method revealed good agreement and proved that there was no significant difference in the accuracy and precision between the results.Â

Experimental and Numerical Study on Vibration-Based Damage Detection and Localization in Laminated Composite Plates

Damage detection in composite materials is crucial for ensuring the safety and reliability of engineering structures. Conventional methods often face challenges in accurately identifying damage in plate-like structures, particularly in scenarios involving multiple damages or small-scale delamination. This study focuses on investigating the detection and localization of delamination in composite plates by employing both experimental and numerical modal analysis. An eight-ply woven Glass-Epoxy composite laminate with and without damage was prepared with the aid of hand lamination technique. Laminate was fixed to a Clamped-Free-Free-Free (CFFF) boundary condition for experimental modal analysis by introducing controlled damage to examine its impact on modal properties. To validate the natural frequencies (NFs) of damaged and undamaged composite laminates, a numerical analysis was conducted using ANSYS Parametric Design Language (APDL). Further, to advance the understanding of using modal shapes and their spatial derivatives for damage localization in composite plates under various damage situations, post-processing of simulation results was conducted using MATLAB. Finite Difference Method has been employed to calculate the derivatives, and a novel damage index (DI) is proposed to enhance damage localization capabilities. The results affirm that the proposed DI is effective and precise in identifying damage in plate-like structures, both for individual and multiple damage scenarios. This research study presents a novel approach for identifying and pinpointing damage in composite plates, thereby making a valuable contribution to the field of structural health monitoring (SHM) application

Long-Term Survival in Patients with Cancers: A SEER-based analysis

Objectives: Long-term survival is an important endpoint in management of different malignancies which is rarely assessed due to unfeasibility of follow-up for long duration of time. In this study, we explored real-world data on cancer’s long-term survival using historical records from the Surveillance, Epidemiology, and End Results (SEER) Program. Besides reporting the 5-year relative survival, we analyzed the 10- and 20- year survival rates for different types of cancers. Additionally, survival trends as a function of time, age, and tumor type were reviewed and reported. Methods: We used SEER*Stat (version 8.3.6.1) for data acquisition from the SEER 9 Regs (Nov 2019 Submission) database. Data of patients diagnosed with cancer between 1975 and 2014 were retrieved and included in the analysis. Results: For patients diagnosed with any malignant disease (n = 4,412,024), there was a significant increase in median overall survival over time (p<0.001). The 20-, 10-, and 5-year survival rates were higher in solid tumors compared to hematological malignancies (50.8% vs. 38%, 57% vs. 47.4%, and 62.2% vs. 57.4%, respectively). The highest 20-year relative survival rates were observed in thyroid cancer (95.2%), germ cell and trophoblastic neoplasms (90.3%), melanoma (86.8%), Wilms’ tumor (86.2%), and prostate cancer (83.5%). Conclusions: Long-term follow-up data were suggestive of high 20-year relative survival rates for most tumor types. Relative survival showed an improving trend over time especially in solid tumors. Keywords: Survival; Neoplasms; SEER Program; Prognosis; United States

Universality in the distribution of caustics in the expanding Universe

We numerically investigate the long--time evolution of density perturbations after the first appearance of caustics in an expanding cosmological model with one--dimensional `single--wave' initial conditions. Focussing on the time--intervals of caustic appearances and the spatial distribution of caustics at subsequent times, we find that the time--intervals of caustic appearances approach a constant, i.e., their time--subsequent ratio converges to 1; it is also found that the spatial distribution of caustics at a given time features some universality rules, e.g., the ratio between the position of the nearest caustic from the center and that of the second nearest caustic from the center approaches a constant. Furthermore we find some rules for the mass distribution for each caustic. Using these universality constants we are in the position to predict the spatial distribution of caustics at an arbitrary time in order to give an estimate for the power spectral index in the fully--developed non--dissipative turbulent (`virialized') regime.Comment: 23 pages, 19 figure

Mechanisms for Introduction of Pseudo Ductility in Fiber Reinforced Polymer Composites- A Review

Advanced polymer matrix composites are gaining the market in their way due to their exceptional specific stiffness, specific strength, fatigue, and corrosion resistance in the field of Auto-Tech, Aero-Tech, Biotech, etc. However, the lack of ductility and catastrophic failure has limited their application in these areas. Hence there is a need to explore means and protocols for designing the reduced factor of safety with high-performance toughened composites. To address this problem, a new generation of high-performance composites with pseudo-ductile or ductile behavior is needed. The ongoing High-Performance Ductile Composite Technology (HiPerDuCT) program jointly between the University of Bristol U.K and Imperial College London to address this challenge by developing newer materials. The fiber architectures made under this project gave a more gradual failure rather than catastrophic failure which improves the mechanical properties. This paper mainly focuses on addressing this evolution of pseudo ductility in fiber-reinforced composites. In addition to this, an attempt has been made to newer possible fiber positions in matrix materials for inducing reasonable ductility in composites

Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes

Can we determine a spin parameter of a black hole by observation of a black hole shadow in an accretion disk? In order to answer this question, we make a qualitative analysis and a quantitative analysis of a shape and a position of a black hole shadow casted by a rotating black hole on an optically thick accretion disk and its dependence on an angular momentum of a black hole. We have found black hole shadows with a quite similar size and a shape for largely different black hole spin parameters and a same black hole mass. Thus, it is practically difficult to determine a spin parameter of a black hole from a size and a shape of a black hole shadow in an accretion disk. We newly introduce a bisector axis of a black hole shadow named a shadow axis. For a rotating black hole a shape and a position of a black hole shadow are not symmetric with respect to a rotation axis of a black hole shadow. So, in this case the minimum interval between a mass center of a black hole and a shadow axis is finite. An extent of this minimum interval is roughly proportional to a spin parameter of a black hole for a fixed inclination angle between a rotation axis of a black hole and a direction of an observer. In order to measure a spin parameter of a black hole, if a shadow axis is determined observationally, it is crucially important to determine a position of a mass center of a black hole in a region of a black hole shadow.Comment: 13 pages, 6 figures, accepted for publication in Ap