Concrete manufacture with un-graded recycled aggregates

Purpose – The purpose of this paper is to investigate whether concrete that includes un-graded recycled aggregates can be manufactured to a comparable strength to concrete manufactured from virgin aggregates. Design/methodology/approach – A paired comparison test was used to evaluate the difference between concrete made with virgin aggregates (plain control) and concrete including recycled waste. Un-graded construction demolition waste and un-graded ground glass were used as aggregate replacements. With regard to concrete, compressive strength is widely used as a measure of suitability as being fit for purpose. Therefore compressive strength was mainly used to compare the different concrete batches; however density was measured across the range of samples. Findings – The findings show that a lower average compressive strength is achieved when compared to the plain control sample manufactured with virgin aggregates. Correct particle packing may not be achieved and grading of aggregates is essential prior to mix design. The recycled aggregate was highly variable in terms of the fine particle content, which affected the water demand of the concrete. Practical implications – This manufacturing practice is considered necessary because of the current trend in using waste products in concrete to replace binders and aggregates; thus reducing the impact on the environment and use of finite natural resources. The research shows the risk of mixing concrete using a simple aggregate replacement without careful aggregate grading and adjustments to the mix design. Originality/value – The paper examines 100 per cent ungraded aggregate replacement with glass and demolition waste

Evaluation of agronomic, seed quality traits, and transcript abundance in conventional high oleic soybeans with mutant FAD2-1A and FAD2-1B genes

Two soybean omega-6 fatty acid desaturase genes [FAD2-1A and FAD2- 1B] are responsible for converting oleic acid into linoleic acid (Okuley et al., 1994). Plant introductions [PI] 603452 and 283327 have naturally occurring mutations in FAD2-1A and FAD2-1B, respectively, which hinder the conversion of oleic acid to polyunsaturated fatty acids. The end result is more functional soybean oil with exceptionally high levels of oleic acid. The homozygous alleles of FAD2-1A and FAD2-1B were combined in a BC3F2:4 [backcross three, second filial generation selected, advanced to the fourth filial generation] population of forty-eight lines and were evaluated in Tennessee. Each line belonged to a double homozygous genotypic class: i) double wild-type [WT] (AABB), ii) mutant FAD2-1A with WT FAD2-1B (aaBB), iii) the converse (AAbb), and iv) double mutant (aabb). All genotypic groups yielded similarly to each other and to three high yielding checks (p\u3c0.05). When one mutant allele was present the high oleic content was increased significantly (aaBB-34.4% and AAbb-26.2%) compared to AABB-21.3%. When both mutations were combined, aabb, the mean oleic content was significantly greater (p\u3c0.05) than all other genotypic groups (80.4%). The range of oleic acid content across all twelve double mutant groups was 77.1% - 81.8%. It appears that the high oleic genotype has a significant effect on total oil, crude protein, and the concentration of five amino acids. The aabb group had significantly more oil (240 ± 1 g kg-1) and crude protein (400 ± 7 g kg-1) than all other groups. This increase in crude protein is consistent with the significantly lowered amino acid concentration (p\u3c0.05) of lysine, methionine, tryptophan, and threonine in the aabb group. Conversely, the high oleic group had the greatest concentration of cysteine (p\u3c0.05). It appears that mutant FAD2-1 genes from PI 603452 and PI 283327 are a useful source for developing high oleic soybean lines in Tennessee with no yield drag. It will be beneficial to explore the effect of these mutant alleles on total oil and protein in the future

Crack healing in cementitious materials including test methods

If concrete is crack free, deleterious substances can be avoided entering the body of the material, that may corrode the rebar or encourage freeze/thaw damage. This paper examines a self healing system of cementitious materials. Microbial induced calcite precipitation was used to heal cracks in concrete with calcite using bacillus bacteria in alkaline conditions to generate a calcite filling material. Self healing of cracked prisms was determined using a water flow and absorption test and the results were expressed to record the healing as a percentage. The findings of the tests showed that a significant degree of self healing had taken place after 56 days after inducing a crack to the concrete prisms and the water flow test was appropriate to determine the degree of self healing taking place. Limitations of this process are such that the process requires a biological laboratory to create the spore impregnated aggregate. Once the aggregate is prepared, the batching process is essentially the same as any normal concrete. A practical use of this system could be developed using cover panels of self healing material to act as permanent formwork, thus placing the healing ingredients where they are needed at a minimum cost. The system has huge potential for the creation of a self repairing sustainable infrastructure

Comparative Effectiveness of Step-up Therapies in Children with Asthma Prescribed Inhaled Corticosteroids : A Historical Cohort Study

This work was supported by the Respiratory Effectiveness Group. Acknowledgments We thank the Respiratory Effectiveness Group for funding this work, Annie Burden for assistance with statistics, and Simon Van Rysewyk and Lisa Law for assistance with medical writing.Peer reviewedPostprin

Микробиологическое осаждение кальцита: применение для залечивания трещин (Microbiological deposition of calcite: crack sealing applications)

В работе исследуются герметизирующие и залечиваю- щие свойства кальцита, выделяемого и осаждаемого микробио- логическим способом в трещинах цементных материалов в ре- зультате соответствующей обработки поверхности. Для герметизации поровой структуры путем осаждением карбо- ната кальция использовались бактерии Sporosarcina pasteurii. Их помещали в жидкую питательную среду, необходимую для интенсивной выработки бактериями кальцита. Испытания, про- веденные на серии из 24 бетонных кубов, обработанных такой жидкостью, позволили оценить влияние микробиологически осажденного кальцита (MОК) на степень укрепления поверхно- сти. Для оценки состояния обработанной поверхности измеряли прибавку массы образцов и твердость материала по Моосу. Кро- ме того, на трех балках из фибробетона были созданы микро- трещины с целью оценить способность Sporosarcina pasteurii к их залечиванию. Обнаружено, что отложения кальцита способны эффективно герметизировать трещины и упрочнять обработан- ную поверхность бетона. Описанная обработка бетона представ- ляет собой органичный восстанавливающий метод, имеющий промышленное значение. This paper investigates the sealing and healing properties of micro-induced calcite precipitation with regard to, surface finish and sealing cracks in cementitious materials. Sporosarcina pasteurii has been used to effectively precipitate calcium carbonate in order to seal porous media. The bacteria are fed a nutrient broth mix to create conditions where microbiologically induced calcite precipitation (MICP) can be effectively used. The tests carried out, assessed the effect of MICP on a sample of twenty-four concrete cubes and to what extent the surface has been consolidated. Weight gain was measured and a MOHs hardness test was used to evaluate the surface condition of the treated surface. In addition, three fibre reinforced concrete beams were micro-cracked to evaluate Sporosarcina pasteurii’s ability to seal cracks that are common in concrete structures globally. Calcite deposits were observed to be effective at sealing cracks and consolidating the surface finish of the concrete. The treatment is an organic remedial method that has industrial applications

Remote learning for students with a disability: Game changer or moment in time? Literature Review

This literature review draws from Australian and international research into the impact of remote learning for students with disability, published between March 2020 and April 2022. The literature relates to pedagogical services provided by early childhood services and schools to support students with disability, rather than therapeutic services. The social implications for students are reviewed along with educational factors, and implications for inclusion and support by schools. Following an overview of the legal and policy frameworks supporting the education of students with disability, this review investigates benefits, challenges and opportunities for both remote learning and transition back to in-person educational settings for students and their families. The themes emerging include flexible approaches to learning, connectedness and wellbeing

Bacterial crack sealing and surface finish application to concrete

This paper investigates the sealing and healing properties micro-induced calcite precipitation with regard to improving concrete finish, sealing cracks and cementing loose surface particles together. Sporosarcina pasteurii has been used to effectively precipitate calcium carbonate in order to seal porous media. The bacteria are fed a nutrient broth mix to create conditions where MICP can be effectively used. The tests carried out, assessed the effect of MICP on a sample of twenty-four concrete cubes and to what extent the surface has been consolidated. The use of an Alicona 4G infinite focus scanner provided comprehensive analysis of how the sample cubes’ topography had been altered following the treatment. In addition, three fibre reinforced concrete beams were micro-cracked to evaluate t S. pasteurii’s ability to seal cracks that are common in concrete structures globally. Calcite deposits were observed to be effective at sealing cracks and consolidating the surface finish of the concrete. The treatment is an organic remedial method that has industrial applications

Moo-vement in the Barn: Absence of Play as an Indicator of Pain in Neonatal Dairy Calves

Previous studies have shown that analgesics and NSAIDs are effective in mitigating the pain response associated with paste disbudding. However, little research has been done on the effect of caustic paste disbudding with and without analgesia on neonatal calves. This study looked to quantify pain response associated with analgesia when neonatal calves are disbudded with caustic paste. To determine this, 10-minute play tests were conducted on calves less than one day of age, at 4-, 28-, and 52-hours and scored. Post-treatment, on calves less than one day of age and scored. The study mainly looked at locomotor play, standing, and lying behaviors. An analysis of the preliminary data found that sham calves had a lower average frequency of locomotor play than calves that were disbudded with and without analgesia. It was also found that there was not a significant difference in standing and lying between the three treatment groups (sham, paste with analgesia, and paste without analgesia). Further research is needed to confirm the preliminary results of this study

The cognitive effect of anticholinergics for patients with overactive bladder

Overactive bladder (OAB) is often treated with medications that block the cholinergic receptors in the bladder (known as anticholinergics). The effect of this medication class on cognition and risk of dementia has been increasingly studied over the past 40 years after initial studies suggested that the anticholinergic medication class could affect memory. Short-term randomized clinical trials demonstrated that the administration of the anticholinergic oxybutynin leads to impaired memory and attention, and large, population-based studies showed associations between several different anticholinergic medications and dementia. However, trials involving anticholinergics other than oxybutynin have not shown such substantial effects on short-term cognitive function. This discordance in results between short-term cognitive safety of OAB anticholinergics and the long-term increased dementia risk could be explained by the high proportion of patients using oxybutynin in the OAB subgroups of the dementia studies, or a study duration that was too short in the prospective clinical trials on cognition with other OAB anticholinergics. Notably, all studies must be interpreted in the context of potential confounding factors, such as when prodromal urinary symptoms associated with the early stages of dementia lead to an increase in OAB medication use, rather than the use of OAB medication causing dementia. In patients with potential risk factors for cognitive impairment, the cautious use of selected OAB anticholinergic agents with favourable physicochemical and pharmacokinetic properties and clinical trial evidence of cognitive safety might be appropriate