MAT-754: INTERNAL CURING OF HIGH PERFORMANCE CONCRETE USING LIGHTWEIGHT AND RECYCLED CONCRETE AGGREGATES

Concrete curing is of paramount importance in order for concrete to meet performance requirements. Conventionally, curing has been conducted by means of water sparkling, wet burlap or a curing compound. For performance and environmental reasons, internal curing has been gaining increased attention. However, more data is needed for the effectiveness of this curing technique when used in various concrete mixtures. This investigation addresses potential utilization of internal curing in high performance concrete (HPC). Internal curing was introduced by means of three aggregates: perlite, pumice and recycled aggregates; all of which were incorporated into HPC mixtures. Conventional mixtures were prepared and were thoroughly cured either by water or by a curing compound or left non-cured. Fresh concrete and Hardened concrete properties were assessed including slump, unit weight, compressive and flexural strength, and durability tests such as shrinkage assessment, rapid chloride permeability test (RCPT) and abrasion resistance. Experimental work is backed up with a simplified feasibility analysis with case study, incorporating initial and future costs to better judge potential of this technique. The outcome of this study uncovers that the addition of pre-wetted lightweight aggregates can prompt an enhancement in concrete workability and durability accompanied by a reduced shrinkage. Compressive and flexural strengths decreased with the increased replacement dosages, however several dosages were tested to reach a figure of optimum replacement. Results of this study reveal the potential of this technology in saving fresh water as well as the costs saved in maintenance and rehabilitation works

Peristaltic Transport of a Physiological Fluid in an Asymmetric Porous Channel in the Presence of an External Magnetic Field

The paper deals with a theoretical investigation of the peristaltic transport of a physiological fluid in a porous asymmetric channel under the action of a magnetic field. The stream function, pressure gradient and axial velocity are studied by using appropriate analytical and numerical techniques. Effects of different physical parameters such as permeability, phase difference, wave amplitude and magnetic parameter on the velocity, pumping characteristics, streamline pattern and trapping are investigated with particular emphasis. The computational results are presented in graphical form. The results are found to be in perfect agreement with those of a previous study carried out for a non-porous channel in the absence of a magnetic field

Immobilization of bovine serum albumin on the chitosan/PVA film

Chitosan/polyvinyl alcohol (Chitosan/PVA) blended film was prepared by direct blend process and solution casting methods. In order to reduce the swelling ratio and enhance the chemical and mechanical stability, Chitosan/PVA film was crosslinked with glutaraldehyde in order to produce Chitosan-g-PVA. Bovine serum albumin (BSA) was used as a model protein to incorporate into the Chitosan-g-PVA. The chemical structure and morphological characteristics of films were studied by FT-IR and scanning electron microscopy (SEM). Mechanical and physical properties of blended films such as tensile properties in the dry and wet states, water uptake and water contact angle measurement were characterized. Blending PVA and chitosan improved strength and flexibility of the films. Crosslinking with glutaraldehyde further improves the tensile strength and decrease the hydrophilicity of films. BSA immobilized on the Chitosan-g-PVA film was calculated as BSA encapsulation efficiency

Evaluation of the Universal Screening Strategy in Qatar for the Management of Pregnant Women Carrying Group B Streptococci

Group B Streptococcus infection (GBS) has emerged as a serious disease, infecting 18,000 people in the United States annually including life-threatening illness in about 8,000 newly-born infants. To evaluate the efficiency of the current universal screening strategy for the management of GBS carriers a retrospective analysis was made of the records of 1,620 pregnant women in Qatar, 550 of whom were found to be carriers. These latter were then used as a group to be compared with 450 uninfected pregnant women in terms of nationality, parity, age, treatment, and outcome. Young and nullipara pregnant women had a high incidence of GBS but there was no significant effect on birth mortality and morbidity regardless of whether or not they received treatment with antibiotics. It is suggested that the cost of screening for GBS at the 35 th week of gestation cannot be justified.qscienc

The negative impact of wearing personal protective equipment on communication during coronavirus disease 2019

BackgroundCoronavirus disease 2019 personal protective equipment has been reported to affect communication in healthcare settings. This study sought to identify those challenges experimentally.MethodBamford-Kowal-Bench speech discrimination in noise performance of healthcare workers was tested under simulated background noise conditions from a variety of hospital environments. Candidates were assessed for ability to interpret speech with and without personal protective equipment, with both normal speech and raised voice.ResultsThere was a significant difference in speech discrimination scores between normal and personal protective equipment wearing subjects in operating theatre simulated background noise levels (70 dB).ConclusionWearing personal protective equipment can impact communication in healthcare environments. Efforts should be made to remind staff about this burden and to seek alternative communication paradigms, particularly in operating theatre environments

Adolescent male with anorexia nervosa: a case report from Iraq

This is the first reported case of an adolescent male with anorexia nervosa in Iraq. This disorder is believed to be rare in males across cultures and uncommon for both genders in Arab countries. The patient met the DSM-IV diagnostic criteria for anorexia nervosa. He was hospitalized and received medical and psychiatric treatment at local facilities as discussed below and responded well to treatment

Scheduling M2M traffic over LTE uplink of a dense small cell network

We present an approach to schedule Long Term Evolution (LTE) uplink (UL) Machine-to-Machine (M2M) traffic in a densely deployed heterogeneous network, over the street lights of a big boulevard for smart city applications. The small cells operate with frequency reuse 1, and inter-cell interference (ICI) is a critical issue to manage. We consider a 3rd Generation Partnership Project (3GPP) compliant scenario, where single-carrier frequency-division multiple access (SC-FDMA) is selected as the multiple access scheme, which requires that all resource blocks (RBs) allocated to a single user have to be contiguous in the frequency within each time slot. This adjacency constraint limits the flexibility of the frequency-domain packet scheduling (FDPS) and inter-cell interference coordination (ICIC), when trying to maximize the scheduling objectives, and this makes the problem NP-hard. We aim to solve a multi-objective optimization problem, to maximize the overall throughput, maximize the radio resource usage and minimize the ICI. This can be modelled through a mixed-integer linear programming (MILP) and solved through a heuristic implementable in the standards. We propose two models. The first one allocates resources based on the three optimization criteria, while the second model is more compact and is demonstrated through numerical evaluation in CPLEX, to be equivalent in the complexity, while it performs better and executes faster. We present simulation results in a 3GPP compliant network simulator, implementing the overall protocol stack, which support the effectiveness of our algorithm, for different M2M applications, with respect to the state-of-the-art approaches

The statistical investigation of type Ib/c and II supernovae and their host galaxies

This is a statistical study of the properties of type Ib/c and II supernovae and of the integral parameters of their spiral host galaxies. The methods of one-dimensional and multivariate statistics were applied to the data sample. It was found that the Ib/c supernovae are more concentrated radially toward the centers of the galaxies than those of type II. The distributions of the radial distances R(SN)/R(25) for the type Ib/c and II supernovae in active galaxies are more concentrated toward the center than in normal galaxies. This effect is stronger for type Ib/c than for type II supernovae.Comment: 8 pages, 2 figure