Strain hardening behavior of lightweight hybrid polyvinyl alcohol (PVA) fiber reinforced cement composites

Experimental results on the strain hardening and multiple cracking behaviors of polyvinyl alcohol (PVA) fiber reinforced cementitious composites under bending are reported in this paper. Different hybrid combinations of PVA fibers with different lengths and volume fractions are considered to reinforce the mortar matrix. Among different hybrid combinations, the composite containing 2% thicker PVA fibers of 12 mm length and 1% thinner PVA fibers of 6 mm length and the composite containing 2% thicker PVA fibers of 24 mm length and 1% thinner PVA fibers of 6 mm length showed the best performance in terms of highest ultimate load, largest CMOD (crack mouth opening displacement) at peak load and multiple cracking behavior. The effects of four types of light weight sands on the strain hardening and multiple cracking behavior of hybrid fiber composites are also evaluated in this study. It has been observed that the ultimate load and CMOD at peak load for all light weight hybrid fiber composites are almost the same irrespective of volume fractions of light weight sand. The composites containing finer light weight sands exhibited higher ultimate load than those containing coarser light weight sands. It is also observed that the hybrid fiber composite containing normal silica sand exhibited higher ultimate load than the composites with light weight sands

A systematic review on materials, design, and manufacturing of swabs

From simple cleaning to metagenomic studies and now the detection of the SARS-2 virus, swabs are absorbent pads with handles that hold significant promise in several applications and properties. Furthermore, the swab is now used for a wide range of medical purposes, such as the collection of bacteria and other pathogens such as influenza and H1N1. Various designs and materials used for the tip have led to a wide range of applications. In this review, we discuss the characteristics of essential tip materials such as rayon, polyester, nylon, and polyurethane in the context of specimen collection from various substrates. Further, this article reviews swab manufacturing techniques, including injection molding and calendar roll pressing, among others. In recent years, advances in additive manufacturing technology have made it possible to produce swabs in a fast and efficient manner. Furthermore, the design for additive manufacturing (DfAM) is given for the production of swabs. We also examine how 3-D printing of bio-resin swabs has revolutionized the manufacturing process, making it autonomous, quicker, more efficient, and environmentally friendly. Additionally, a shortage of medical devices for testing the SARS-2 virus has zealously motivated the medical industry to revolutionize through additive manufacturing of swabs, thus revolutionizing the medical industry. In conclusion, the limitations of the current techniques and future directions for swabs are discussed

Hybrid fiber reinforcement and crack formation in cementitious composite materials

The use of different types of fibers simultaneously for reinforcing cementitious matrices is motivated by the concept of a multi-scale nature of the crack propagation process. Fibers with different geometrical and mechanical properties are used to bridge cracks of different sizes from the micro- to the macroscale. In this study, the performance of different fiber reinforced cementitious composites is assessed in terms of their tensile stress-crack opening behavior. The results obtained from this investigation allow a direct quantitative comparison of the behavior obtained from the different fiber reinforcement systems. The research described in this paper shows that the multi-scale conception of cracking and the use of hybrid fiber reinforcements do not necessarily result in an improved tensile behavior of the composite. Particular material design requirements may nevertheless justify the use of hybrid fiber reinforcements.Fundação para a Ciência e a Tecnologia (FCT) - SFRH / BD / 36515 / 200

Patterns oF organoPHosPHorous Poisoning attenDing a teacHing HosPital

The objective of this was to study the pattern of patients of organophosphorous (OP) poisoning attending Kathmandu Medical College Teaching Hospital (KMCTH). This is a retrospective study of OP poisoning from hospital records were analyzed meticulously and data extracted. Data col-lected were: patient’s demographics, motive for poisoning, type of OP poison, arrival time, time since ingestion, patient’s vitals, predisposing factors, serum cholinesterase levels, treatment given, duration of hospital stay and mortality. A total of 47 patients of OP poisoning attended KMCTH from Aug 2003 to July 2005. 22(46.8%) cases were male and 25(53.2%) were female. The maximum number of patients were between the age of 20-40 (33-70.2%). Married patients outnumbered the unmarried (35/74.5% vs 12/25.5%). The most common motive for poisoning was suicidal, 41 cases (87.2%). Metacid (methyl-parathion) was the most commonly used OP compounds in 32 (68%) patients. Interpersonal marital relationship seemed to be the commonest predisposing factor, 23 cases (48.9%).The commonest time of presentation was between 6 pm-12 midnight. 7(57.4%) cases presented within 2 hours of ingestion of the poison. Serum cholinesterase level measured after full atropinisation was >50% of normal level in 17 cases (36.2%). 10 cases (21.3%) required respiratory support. Intermediate syndrome (IMS) was observed in 3 cases. Overall mortality occurred in 3 cases (6.4%). This study highlights the problem of OP poisoning in our region. Establishment of strict policies against the sale and availability of insecticides and pesticides which are freely avail-able in the market is an effective way to control OP poisoning. Key Words: Organophosphate poisoning (OPP), OP compounds, insecticides, pesticides

Effect of the displacement rate and inclination angle in steel fiber pullout tests

This paper summarizes the results obtained in an experimental campaign on the effect of the displacement pullout rate and the inclination angle of the steel fiber pullout tests. For that purpose, specimens were obtained from a self-compacting concrete with a compressive strength of 86 MPa. In the experimental program, hooked-end steel fibers of 0.75 mm diameter and 60 mm length were used. Tests were executed with both hooked-end fibers, and smooth fibers obtained from the former by cutting the hooked end. For both type of fibers, their embedment length into concrete was 20 mm, and the influence of fiber inclination angle toward the load direction was investigated by adopting values of 0∘, 30∘ and 60∘. The tests were performed at displacement rates of 0.01, 0.1 and 1 mm/s. The results have shown that the peak pullout load increased with the inclination angle, in particular for the smooth series. Furthermore, higher displacement rates led to a higher energy absorption capacity for the pullout of the smooth fibers, while the energy absorption remained almost stable for hooked-end fibers.project BIA2015-68678-C2-1-R. M. Tarifa appreciates the financial support from the Department of Applied Mechanics and Project Engineering, UCLM (2018), and from the Programa propio de I+D+i de la Universidad Politécnica de Madrid para realizar estancias de investigación internacional igual o superior a un mes (2019), to do two stays at the University of Minho, Guimarães, Portugal. E. Poveda acknowledges the funding from the International Campus of Excellence CYTEMA and the University of Castilla-La Mancha, throughout Ayudas para estancias en universidades y centros de investigación en el extranjero en 2019 en el ámbito del plan propio de investigación susceptibles de cofinanciación por el Fondo Europeo de Desarrollo Regional (FEDER), Programa 010100021 to fund her stays in the University of Minho during 2018 and 2019, respectively. The authors thank the support of the Department of Civil Engineering and the Laboratory of the Structural Division (LEST), University of Minh

Application of recycled tyre cord in concrete for shrinkage crack control

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43027/1/10855_2004_Article_BF00275355.pd

Usefulness of hospital emergency department records to explore access to injury care in Nepal

© 2016, Bhatta et al. Background: Injuries are a major public health problem worldwide. Despite increasing morbidity and mortality from injuries in Nepal, it is not recognised in the government’s policy and programmes and few population-based studies have been published. This study describes the usefulness of hospital emergency department records to explore access to injury care in Nepal. Methods: A retrospective ED-based study was conducted at a governmental hospital in Nepal to review the routinely collected data for 1year (1 January 2010 to 31 December 2010). The study was designed to provide cross-sectional data to describe the distribution of injuries by age, gender, ethnic group and injury mechanism. Results: Results showed that twice as many males as females attended the emergency department (14.6 vs. 7.0 per 1000), attendance varied by age with most (39.8%) attendances in young adults of working age and over half of attendances were from just two ethnic groups (Brahmin (26%) and Tamang (25.5%). Road traffic injuries were the most common cause of injury (37.6%). Conclusions: This study therefore showed the feasibility of using routinely collected hospital emergency department data to monitor injury inequalities in Nepal