An evolutionary approach to modelling concrete degradation due to sulphuric acid attack

Concrete corrosion due to sulphuric acid attack is known to be one of the main contributory factors for degradation of concrete sewer pipes. This paper proposes to use a novel data mining technique, namely, evolutionary polynomial regression (EPR), to predict degradation of concrete subject to sulphuric acid attack. A comprehensive dataset from literature is collected to train and develop an EPR model for this purpose. The results show that the EPR model can successfully predict mass loss of concrete specimens exposed to sulphuric acid. Parametric studies show that the proposed model is capable of representing the degree to which individual contributing parameters can affect the degradation of concrete. The developed EPR model is compared with a model based on artificial neural network (ANN) and the advantageous of the EPR approach over ANN is highlighted. In addition, based on the developed EPR model and using an optimisation technique, the optimum concrete mixture to provide maximum resistance against sulphuric acid attack has been identified

Decolorization of two synthetic dyes using the purified laccase of Paraconiothyrium variabile immobilized on porous silica beads

BACKGROUND: Decolorization of hazardous synthetic dyes using laccases in both free and immobilized form has gained attention during the last decades. The present study was designed to prepare immobilized laccase (purified from Paraconiothyrium variabile) on porous silica beads followed by evaluation of both free and immobilized laccases for decolorization of two synthetic dyes of Acid Blue 25 and Acid Orange 7. Effects of laccase concentration, pH and temperature alteration, and presence of 1-hydroxybenzotriazole (HBT) as laccase mediator on decolorization pattern were also studied. In addition, the kinetic parameters (K( m ) and V( max )) of the free and immobilized laccases for each synthetic dye were calculated. RESULTS: Immobilized laccase represented higher temperature and pH stability compare to free one. 39% and 35% of Acid Blue 25 and Acid Orange 7 was decolorized, respectively after 65 min incubation in presence of the free laccase. In the case of immobilized laccase decolorization percent was found to be 76% and 64% for Acid Blue 25 and Acid Orange 7, respectively at the same time. Increasing of laccase activity enhanced decolorization percent using free and immobilized laccases. Relative decolorization of both applied dyes was increased after treatment by laccase-HBT system. After nine cycles of decolorization by immobilized laccase, 26% and 31% of relative activity were lost in the case of Acid Blue 25 and Acid Orange 7, respectively. CONCLUSIONS: To sum up, the present investigation introduced the immobilized laccase of P. variabile on porous beads as an efficient biocatalyst for decolorization of synthetic dyes

Modelling the variation of suction pressure during caisson installation in sand using FLAC3D

A suction caisson is an upturned ‘bucket’ of cylindrical shape made from steel. This type of foundation has been very popular in the oil and gas industry and the current trend is to extend its use to offshore wind farms. Seepage conditions play a pivotal role in suction caisson installation process in sand. Pressure gradients generated by imposed suction inside the caisson cavity cause an overall reduction in the soil resistance around the caisson wall and tip. This transient soil loosening around the caisson wall helps caisson penetration into the seabed. In this paper, we present a study of the role of seepage on the suction caisson installation process in homogenous sand. We also investigate the effects of seepage conditions on soil resistance to caisson penetration with a particular focus on how frictional and tip resistances are differently affected. For this purpose, a series of numerical models are developed using FLAC3D. These models are used to investigate the variation of suction pressure during caisson installation in homogenous sand and to predict the amount of suction required to penetrate the caisson to a certain depth. An explicit strategy is used for each embedment depth, which consists of updating current suction based on displacement history available after the previous prescribed displacement increment. The numerical models are developed for different caisson sizes and wall thicknesses to study the effects of caisson geometry on soil resistance during caisson installation. Problem dimensions are normalised with respect to the diameter of the caisson in order to obtain the results that can be applied to any caisson size. The results showed that suction pressure tends to increase with the embedment depth. Additionally, the overall behaviour and the pressure variation with depth are similar for caissons of different sizes and wall thicknesses. Finally, in order to validate the developed numerical models, data from centrifuge tests are investigated and compared with the results obtained from this study. The developed finite difference models are found to be in good agreement with centrifuge tests, in particular for thicker caissons (t/D = 1%)

Exploring the Lived Experiences of Mothers of Children with Specific Learning Disability (SLD): A Phenomenological Study

Introduction: The presence of a child with a specific learning disability in the family who needs care and has special educational problems is a source of stress for mothers, affecting their mental health and adjustment. This study aimed to explore the lived experiences of mothers of children with specific learning disability (SLD). Methods: This qualitative study was conducted using a phenomenological approach. The participants were 14 mothers of children with specific learning disability (SLD) whose data were collected through semi-structured interviews. The participants were selected using purposive sampling and the collected data were analyzed via Colaizzi's method of data analysis. Results: Analysis of the data revealed 4 main themes including “impact on family”, “the mother’s life”, “the student’s problems”, “concerns”, and “needs”, and 14 subthemes. Conclusion: The present study showed that specific learning disability has diverse effects on the child, mother, and family, and recognizing these effects can pave the way for taking supportive and therapeutic measure

Clinical Outcomes of Femtosecond Laser-assisted Implantation of 325-Degree Versus 340-Degree Arc Length Intracorneal Ring Segments in Naive Keratoconic Eyes

Purpose: To evaluate and compare clinical outcomes after femtosecond laser-assisted implantation of 325-degree versus 340-degree arc length intracorneal ring segments (ICRS) in eyes with keratoconus (KCN). Methods: In this prospective non-randomized interventional case series, 23 eyes of 21 patients diagnosed with KCN, underwent femtosecond laser-assisted implantation of two types of ICRS, which included a 325-degree ICRS (Group 325) and a 340-degree ICRS (Group 340). The primary outcome measures were uncorrected distance visual acuity (UDVA), and the secondary outcome measures included corrected distance visual acuity (CDVA), sphere, cylinder, mean refractive spherical equivalent (MRSE), keratometry, vectorial change in corneal astigmatism, and the location of maximum keratometry relative to the corneal apex. The study groups were compared using the primary and secondary outcome measures obtained at postoperative months six and 12. Results: Groups 325 and 340 consisted of 10 and 13 eyes, respectively. The two groups were comparable in terms of parameters measured preoperatively. On comparison to the baseline values, both study groups exhibited a significant increase in UDVA and CDVA measured at postoperative month six (Ps < 0.05) and a significant decrease in the sphere, cylinder, spherical equivalent refraction, and keratometry readings measured at postoperative months six and 12 (Ps < 0.05). No significant differences were observed between the two groups in terms of visual, refractive, and keratometric outcomes at any time point. No intraoperative or postoperative complications were observed in any of the study groups. Conclusion: Both the 325-degree ICRS and the 340-degree ICRS effectively and equally improved visual, refractive, and keratometric outcomes in keratoconic eyes

Understanding the Factors Influence Expressed Emotion in Mothers of Children Autistic with Autism (Mixed-Method Research)

Introduction: Expressed emotion has been used as a measure of the relationship between parents and children. This study aimed to compare expressed emotion among mothers and finally of children with and without autism and to investigate the factors influence it among them. Method: The Embedded Design Mixed Research Method was used to assess the quantity of mothers expressed emotion. The study population consisted of 50 mothers of the children with autism that their children ages were between 3-13 years were selected non-randomly and 50 mothers of children with normal growth at the same age were selected randomly. At the second phase, qualitative research method was used to examine the factors influenced mothers expressed emotions. Results: The mothers of the children with autism had higher score both in the total score of expressed emotion, and emotional over-involvement (EQI) and criticism. In addition, five factors influenced the mothers of the children with autism to be of high expressed emotion that were "being worried about others comment", "being worried about the child's future", "just paying attention to child's needs and ignoring their own and other family member’s needs", "comparing their child with other children", and "blaming and criticizing the child". Conclusion: According to the results, it is recommended that in rehabilitation of children with autism, intervention procedures that consider parents expressed emotion should be developed as well. Keywords: Mixed research method, Expressed emotion, Autism, Mother

Somatic Embryogenesis and Plant Regeneration in Evening Primrose (Oenothera biennis L.)

Callus induction responses and regeneration through callus-mediated SE were studied from evening primrose (Oenothera biennis L.) as an important medicinal plant of Onagraceae mainly known for its gamma-linoleic acid (GLA) content. The effects of cytokinins, 6-Benzylaminopurine (BAP) and N-(2-furfurylamino)1-H-purine-6-amine [Kinetin (Kin)] and their concentrations (0, 0.5, 1.0 and 1.5 mg/l) in combinations with 2,4-dichlorophenoxyacetic acid (2, 4-D) concentrations (0.25, 0.75 mg/l) on callus induction and SE for three explant types (petiole, leaf and epical bud) of "Shiraz" variety were separately evaluated. In all types of explants, the highest callus fresh weights belonged to 1 mg/l BAP or Kin in combinations with 2, 4-D (either 0.25 mg/l or 0.75 mg/l). The maximum fresh weight of callus was obtained from leaf explants plated on culture medium containing of 0.25 mg/l 2, 4-D and 1 mg/l Kin. The maximum The maximum number of embryos was achieved from leaf explants related to 0.75 mg/l 2, 4-D and 1 mg/l Kin. plantlets were successfully raised from in vitro developed embryos. Efficient plant regeneration via SE may provide a reliable system for studying the molecular mechanism of SE and a route for the genetic transformation of evening primrose