Effects of Corrugations on Stiffness Properties of Composite Beams for Structural Applications

Composites have high strength-to-weight ratios, which is particularly desired for applications with weight restrictions. Common composite materials such as carbon fiber reinforced plastic (CF) and fiber glass reinforced plastic (FG) were used in this research. While composite materials possess high stiffness and strength properties, the stiffness of composite laminates may be maximized by changing the geometry. By adding corrugations, the flexural stiffness is increased in one direction compared to the stiffness of a flat part with the same amount of material. Thus, stiffness increases without a change in weight. The primary goal of this research was to investigate the stiffness characteristics of corrugated composite laminates under tensile and flexural load. The chosen corrugation geometry for investigation was a trapezoid. To observe the effects of corrugations, both flat and corrugated coupons were tested experimentally with the same procedures. Stiffness was calculated experimentally, analytically, and numerically in both directions. In this study, the longitudinal direction was defined as perpendicular to the corrugations and transverse direction was defined as the direction along the corrugations. The effects on stiffnesses of corrugated and flat composites were measured by comparing changes to the stiffness ratios in tension and bending. The stiffness ratio is the ratio of longitudinal stiffness to transverse stiffness. The secondary aim of this research was to compare the corrugation effects on FG weave and cross-ply CF. This was interesting to observe the difference in corrugation effects on different composite materials. The FG laminates were manufactured from four plies of pre-impregnated Cytec MXB 7701/7781. The CF laminate consisted of five plies of pre-impregnated unidirectional Tencate TC250/M46J. The layup orientation of the CF laminate had alternating 0◦ and 90◦ plies, where the 0 ◦ plies were in the transverse direction. Plies were directly laid on a flat plate and aluminum mold for flat and corrugated specimens, respectively. All flat and corrugated composites were cured in an autoclave under respective recommended cure cycles for each material. The tension and three-point bend tests were conducted on an Instron 8800 where the load was applied at a rate of 0.05 inches per minute. The tensile ultimate load was the same between corrugated and flat specimens in the longitudinal direction. Meanwhile, the tensile ultimate load was greatly reduced for corrugated specimens in the transverse direction when compared to the flat specimens. Thus, corrugations had a larger impact in the transverse direction under tensile load for both materials. By corrugating the composite layups, the ratio of stiffness in the longitudinal to extensional direction increases. For FG test coupons, the extensional stiffness ratio was increased from 1.0 to 49.3 due to corrugations. The flexural stiffness ratio was increased from 0.3 to 187.1 in corrugated FG coupons. For CF test coupons, the extensional stiffness ratio increased from 0.7 to 61.3. The flexural stiffness ratio of CF test coupons increased from 0.3 to 81.4. Corrugations had a greater effect on the cross-ply CF for both extensional and flexural stiffnesses

Industrial Pollution: Contamination of Surface Water & Human Health in Veerapura, Bangalore

Articlehttp://deepblue.lib.umich.edu/bitstream/2027.42/96998/1/UMURJ-Issue07_2010-MVallurupalli.pd

Optimality conditions and constraint qualifications for cardinality constrained optimization problems

The cardinality constrained optimization problem (CCOP) is an optimization problem where the maximum number of nonzero components of any feasible point is bounded. In this paper, we consider CCOP as a mathematical program with disjunctive subspaces constraints (MPDSC). Since a subspace is a special case of a convex polyhedral set, MPDSC is a special case of the mathematical program with disjunctive constraints (MPDC). Using the special structure of subspaces, we are able to obtain more precise formulas for the tangent and (directional) normal cones for the disjunctive set of subspaces. We then obtain first and second order optimality conditions by using the corresponding results from MPDC. Thanks to the special structure of the subspace, we are able to obtain some results for MPDSC that do not hold in general for MPDC. In particular we show that the relaxed constant positive linear dependence (RCPLD) is a sufficient condition for the metric subregularity/error bound property for MPDSC which is not true for MPDC in general. Finally we show that under all constraint qualifications presented in this paper, certain exact penalization holds for CCOP

Carbon Free Boston: Transportation Technical Report

Part of a series of reports that includes: Carbon Free Boston: Summary Report; Carbon Free Boston: Social Equity Report; Carbon Free Boston: Technical Summary; Carbon Free Boston: Buildings Technical Report; Carbon Free Boston: Waste Technical Report; Carbon Free Boston: Energy Technical Report; Carbon Free Boston: Offsets Technical ReportOVERVIEW: Transportation connects Boston’s workers, residents and tourists to their livelihoods, health care, education, recreation, culture, and other aspects of life quality. In cities, transit access is a critical factor determining upward mobility. Yet many urban transportation systems, including Boston’s, underserve some populations along one or more of those dimensions. Boston has the opportunity and means to expand mobility access to all residents, and at the same time reduce GHG emissions from transportation. This requires the transformation of the automobile-centric system that is fueled predominantly by gasoline and diesel fuel. The near elimination of fossil fuels—combined with more transit, walking, and biking—will curtail air pollution and crashes, and dramatically reduce the public health impact of transportation. The City embarks on this transition from a position of strength. Boston is consistently ranked as one of the most walkable and bikeable cities in the nation, and one in three commuters already take public transportation. There are three general strategies to reaching a carbon-neutral transportation system: • Shift trips out of automobiles to transit, biking, and walking;1 • Reduce automobile trips via land use planning that encourages denser development and affordable housing in transit-rich neighborhoods; • Shift most automobiles, trucks, buses, and trains to zero-GHG electricity. Even with Boston’s strong transit foundation, a carbon-neutral transportation system requires a wholesale change in Boston’s transportation culture. Success depends on the intelligent adoption of new technologies, influencing behavior with strong, equitable, and clearly articulated planning and investment, and effective collaboration with state and regional partners.Published versio

Influences of DMP on the Fertilization Process and Subsequent Embryogenesis of Abalone (Haliotis diversicolor supertexta) by Gametes Exposure

Di-methyl phthalate (DMP), a typical endocrine disrupting chemical (EDC), is ubiquitously distributed in aquatic environments; yet studies regarding its impact on gametes and the resulting effects on embryogenesis in marine gastropods are relatively scarce. In this study, the influences of DMP on the gametes and subsequent developmental process of abalone (Haliotis diversicolor supertexta, a representative marine benthic gastropod) were assessed. Newborn abalone eggs and sperm were exposed separately to different DMP concentrations (1, 10 or 100 ppb) for 60 min. At the end-point of exposure, the DMP-treated eggs and sperm were collected for analysis of their ultra-structures, ATPase activities and total lipid levels, and the fertilized gametes (embryos) were collected to monitor related reproductive parameters (fertilization rate, abnormal development rate and hatching success rate). Treatment with DMP did not significantly alter the structure or total lipid content of eggs at any of the doses tested. Hatching failures and morphological abnormalities were only observed with the highest dose of DMP (100 ppb). However, DMP exposure did suppress sperm ATPase activities and affect the morphological character of their mitochondria. DMP-treated sperm exhibited dose-dependent decreases in fertilization efficiency, morphogenesis and hatchability. Relatively obvious toxicological effects were observed when both sperm and eggs were exposed to DMP. Furthermore, RT-PCR results indicate that treatment of gametes with DMP changed the expression patterns of physiologically-regulated genes (cyp3a, 17β-HSD-11 and 17β-HSD-12) in subsequent embryogenesis. Taken together, this study proofed that pre-fertilization exposure of abalone eggs, sperm or both to DMP adversely affects the fertilization process and subsequent embryogenesis

Body-Mind Connectedness: Integrative Body-Mind-Spirit Group Work for Depressed Persons with Salient Somatic Disturbances

Globally, depression frequently comorbid with a variety of physical illnesses, which exert substantial mental and somatic distresses on patients. Sleep disturbance is one of the common conditions reported by individuals with either, mental or physical illnesses. Complex interaction among depression, sleep and physical illnesses highlighted the essential mind‐body connection in the planning of integrative care and other clinical services. A number of eastern mind‐body practices, such as Qigong, acupuncture and meditation, have been frequently studied indicating the efficacy of mind‐body connection in complementary therapies. This chapter will introduce the integrative body‐mind‐spirit (I‐BMS) group work, which has been found effective in addressing comorbid depressed mood and somatic afflictions, especially sleep disturbances among Hong Kong Chinese adults

Tai chi as an alternative exercise to improve physical fitness for children and adolescents with intellectual disability

© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Objective: The purpose of this study was to investigate the effects of Tai Chi (TC) on anthropometric parameters and physical fitness among children and adolescents with intellectual disabilities (ID). Methods: Sixty-six Chinese individuals engaged in sport-related extracurricular activities (TC and aerobic exercise (AE)) as exercise interventions or arts/crafts activities as a control condition (CON). The experimental protocol consisted of a baseline assessment, a 12-week intervention period, and a post-intervention assessment. Results: Significant interaction effect was only observed in the performance of a 6-min walk test. After 12 weeks of intervention, the AE group had significant changes in body mass index (p = 0.006, d = 0.11), sit-ups (p = 0.030 and d = 0.57), and 6-min walk test (p = 0.005, d = 0.89). Significant increases in vertical jump (p = 0.048, d = 0.41), lower-limb coordination (p = 0.008, d = 0.53), and upper-limb coordination (p = 0.048, d = 0.36) were observed in the TC group. Furthermore, the TC group demonstrated significantly greater improvements on balance compared to the control group (p = 0.011). Conclusions: TC may improve leg power and coordination of both lower and upper limbs, while AE may be beneficial for body mass index, sit-ups and cardiorespiratory fitness