Attityder till cannabis – Intervjuer med unga vuxna

Syftet med denna studie är att undersöka en grupp unga vuxnas attityder till cannabis. Att undersöka och förstå attityder till cannabis är värdefullt för att effektivisera strategier att bemöta olika problem menar experter. Studien ämnar undersöka deltagarnas uppfattning om cannabis, deltagarnas uppfattning om olika lagstiftningars betydelse i relation till cannabis samt deltagarnas uppfattning om omgivningens attityder till cannabis. I Sverige är det främst unga killar/men i åldern 16-29 som använder cannabis och uppskattningsvis är det omkring 9 procent. Den valda metoden var kvalitativ ansats med en fokusgrupp som bestod av fem unga vuxna killar i åldern 20-25. Ur fokusgruppen framkom det att erfarenhet, media, samhälle och olika lagstiftningar är några av de viktiga faktorer som har en direkt koppling till attityderna till cannabis. Tidigare forskning påvisar dessa samband men denna korrelation kan även bero på många andra bakomliggande komplexa förklaringar och faktorer vad det gäller attityder till cannabis

Recycled Plastic Fibers for Minimizing Plastic Shrinkage Cracking of Cement Based Mortar

The development of new construction materials using recycled plastic is important to both the construction and the plastic recycling industries. Manufacturing of fibers from industrial or post-consumer plastic waste is an attractive approach with such benefits as concrete performance enhancement, and reduced needs for land filling. The main objective of this study is to investigate the effect of plastic fibers obtained locally from recycled waste on plastic shrinkage cracking of ordinary cement based mortar. Parameters investigated include: Fiber length ranging from 20 to 50 mm, and fiber volume fraction ranging from 0% to 1.5% by volume. The test results showed significant improvement in crack arresting mechanism and substantial reduction in the surface area of cracks for the mortar reinforced with recycled plastic fibers compared to plain mortar. Furthermore, test results indicated that there was a slight decrease in compressive strength of mortar reinforced with different lengths and contents of recycled fibers compared to plain mortar. This study suggests that adding more than 1% of RP fibers to mortar, can be used effectively for controlling plastic shrinkage cracking of cement based mortar, and thus results in waste reduction and resources conservation

The Efficiency of the PQ4R Strategy in Understanding the Mathematical Proof among the Primary School Female Students

The purpose of the study is to examine the efficiency of the PQ4R strategy in understanding the mathematical proof among primary school female students. To achieve the purpose of the study, the analytical approach is used. The sample of the study consists of 40 female students divided into two groups, one is experimental and the other is control, with each group consisting of (20) students. As for the validity and reliability of the study instrument, they are validated as required by a group of highly respective validators. The results of the study show that there is an efficiency of the teaching strategy using (PQ4R) in improving the understanding of mathematical proof for female primary school students. DOI: 10.7176/JEP/11-16-09 Publication date:June 30th 202

Optimal conditions for olive mill wastewater treatment using ultrasound and advanced oxidation processes

© 2019 Elsevier B.V. The treatment of olive mill wastewater (OMW) in Jordan was investigated in this work using ultrasound oxidation (sonolysis) combined with other advanced oxidation processes such as ultraviolet radiation, hydrogen peroxide (H2O2) and titanium oxide (TiO2) catalyst. The efficiency of the combined oxidation process was evaluated based on the changes in the chemical oxygen demand (COD). The results showed that 59% COD removal was achieved within 90 min in the ultrasound /UV/TiO2 system. A more significant synergistic effect was observed on the COD removal efficiency when a combination of US/UV/TiO2 (sonophotocatalytic) processes was used at low ultrasound frequency. The results were then compared with the COD values obtained when each of these processes was used individually. The effects of different operating conditions such as, ultrasound power, initial COD concentration, the concentration of TiO2, frequency of ultrasound, and temperature on the OMW oxidation efficiency were studied and evaluated. The effect of adding a radical scavenger (sodium carbonate) on the OMW oxidation efficiency was investigated. The results showed that the sonophotocatalytic oxidation of OMW was affected by the initial COD, acoustic power, temperature and TiO2 concentration. The sonophotocatalytic oxidation of OMW increased with increasing the ultrasound power, temperature and H2O2 concentration. Sonolysis at frequency of 40 kHz combined with photocatalysis was not observed to have a significant effect on the OMW oxidation compared to sonication at frequency of 20 kHz. It was also found that the OMW oxidation was suppressed by the presence of the radical scavenger. The COD removal efficiency increased slightly with the increase of TiO2 concentration up to certain point due to the formation of oxidizing species. At ultrasound frequency of 20 kHz, considerable COD reduction of OMW was reported, indicating the effectiveness of the combined US/UV/TiO2 process for the OMW treatment

Testing of a Potentially Used Antiseptic Consists of Povidon Iodine, Hydrogen Peroxide and Aloe Vera

In this study a new antiseptic was formulated and tested to match the effectiveness against microorganisms. The formulation consisted of Povidone - Iodine (PVP-I) (10%), H2O2 (3%) and Aloe Vera gel (pure). Different ratios of these materials were prepared within the acceptable range of pH for an antiseptic (3-6). The prepared samples were tested. The In Vitro test was performed by using four bacteria, two were Gram-Positive (Staphylococcus aureus and Bacillus cereus) and two were Gram-Negative (Escherichia coli and Pseudomonas aeruginosa). The new antiseptic showed 100% killing rate for E. coli, Ps. aeruginosa and S. aureus and 96.4667% killing rate for B. cereus. When the new antiseptic was compared with two common antiseptics (chloroxylenol (Dettol) and alcohol-based antiseptic), it was superior because the alcoholic antiseptic showed 100% killing rate for E. coli, Ps. aeruginosa and S. aureus and 89.8000% for B. cereus. The Dettol did not show killing rate against bacteria. Ex vivo test was carried out using the sample that showed the highest effectiveness in the In Vitro test. This was performed by applying the formulation on the skin of lab mice after wounding and contaminating the wounds with two bacteria (Staphylococcus aureus and Escherichia coli). After applying the antiseptic on the wounds, swabs from the wounds were taken for testing. The new antiseptic showed amazing efficacy against bacteria by leaving agar dish completely empty from bacteria. In vivo test was also conducted using the polymerase chain reaction (PCR) test for COVID-19. The new antiseptic did not show effectiveness against Coronavirus because the virus could not be isolated like bacteria

Finite element-based micromechanical modeling of the influence of phase properties on the elastic response of cementitious mortars

This study reports the influence of inclusion stiffness and its distribution on the stress distributions in the microstructural phases of different cementitious mortars using microstructure-guided finite element simulations. Randomly generated periodic microstructures with single/multiple inclusion sizes and random spatial distribution, subjected to periodic boundary conditions and a strain-controlled virtual testing regime are chosen for final analysis. Numerical simulations reveal: (i) the differences in locations/magnitudes of stress concentrations as a function of inclusion stiffness and size distribution, and (ii) the sometimes detrimental influence of matrix and interface stiffening/strengthening on the overall composite response, leading to material design strategies when non-conventional inclusions are used in cementitious systems for special properties. The constitutive behavior in the linear elastic regime is extracted based on the predicted dominant principal stresses and strains in the representative area element. Thus, in addition to the microstructural phase stresses, this methodology also provides predictions of the composite elastic modulus, which are observed to be more reliable than those obtained from analytical prediction models

An experimental and analytical investigation of reinforced concrete beam-column joints strengthened with a range of CFRP schemes applied only to the beam

This paper investigates the experimental and analytical behaviour of beam-column joints that are subjected to a combination of torque, flexural and direct shear forces, where different Carbon Fibre Polymer (CFRP) strengthening wraps have been applied only to the beam. These wrapping schemes have previously been determined by the research community as an effective method of enhancing the torsional capacities of simply supported reinforced concrete beams. In this investigation, four 3/4-scale exterior beam-column joints were subjected to combined monotonic loading; three different beam wrapping schemes were employed to strengthen the beam region of the joint. The paper suggests a series of rational formulae, based on the space truss mechanism, which can be used to evaluate the joint shear demand of the beams wrapped in these various ways. Further, an iterative model, based on the average stress-strain method, has been introduced to predict joint strength. The proposed analytical approaches show good agreement with the experimental results. The experimental outcomes along with the adopted analytical methods reflect the consistent influence of the wrapping ratio, the interaction between the combined forces, the concrete strut capacity and the fibre orientation on the joint forces, the failure mode and the distortion levels. A large rise in the strut force resulting from shear stresses generated from this combination of forces is demonstrated and leads to a sudden-brittle failure. Likewise, increases in the beams’ main steel rebar strains are identified at the column face, again influenced by the load interactions and the wrapping systems used

Tensile behavior of fiber-reinforced DSP cement.

The mechanisms responsible for the improvement in tensile strain capacity of fiber reinforced densified small particles (FR-DSP) cement containing high volume fraction of discontinuous steel fibers, randomly distributed throughout the matrix were investigated. Existing micromechanical models based on energy principles were further improved for predicting the tensile strain capacity of the composite, which is highly dependent on the properties of the fiber matrix interface. The debonding and pullout behavior of a single steel fiber from cement based matrices was examined using a specially designed apparatus which provides simultaneous results on total fiber displacement versus load in addition to monitoring the fiber displacement at the free end. In this apparatus the fiber goes through the entire specimen, which made it possible to determine the point of complete debonding. To control the embedment length, a plastic tube was inserted around the fiber. The described method coupled with an appropriate analyses provides a quantitative determination of interfacial properties which are relevant to toughening of brittle materials through fiber-reinforcement. The technique was used on a high strength cement-based matrix (DSP), and on an ordinary strength cement matrix. Other parameters investigated included fiber embedment length, fiber volume fraction in the cement matrix, and matrix surface effect. A model was proposed for analyzing the debonding process in single fiber pullout tests. The model provides a simple and direct way of estimating the debonding energy and the frictional bond strength of the fiber/matrix interface, by evaluating the part of the area under the pullout curve corresponding to pure debonding. The results indicate that: (1) the dense DSP matrix has significantly improved interfacial properties as compared to the ordinary strength matrix; (2) the major energy of pullout in both systems is due to sliding; and (3) both the debonding energy and sliding energy increase with fiber embedment length. These results are important for understanding the role of steel fibers in improving the tensile properties of high performance fiber reinforced composites. The results obtained from uniaxial tension tests on FR-DSP containing small amount of main reinforcement confirmed an increase in the elastic and inelastic strains of the composite as predicted from previous models.Ph.D.Civil EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/104424/1/9527578.pdfDescription of 9527578.pdf : Restricted to UM users only