Search results for: compressive test

Authors: Shu Hwang Ang, Choo Yee Yu, Geik Yong Ang, Yean Yean Chan, Yatimah Binti Alias, And Sook Mei Khor

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With the high prevalence of Type 2 diabetes mellitus across the world, the morbidities and mortalities associated with Type 2 diabetes have significant impact on the production line for a nation. With routine scheduled clinical visits to manage Type 2 diabetes, diabetic patients with hectic lifestyles can have low clinical compliance. Hence, it often decreases the effectiveness of diabetic management personalized for each diabetic patient. Here, we report a useful developed point-of-care (POC) device that detect glycated hemoglobin (HbA1c, biomarker for long-term Type 2 diabetic management). In fact, the established POC devices certified to be used in clinical setting are not only expensive ($ 8 to $10 per test), they also require skillful practitioners to perform sampling and interpretation. As a paper-based biosensor, the developed HbA1c biosensor utilized lateral flow principle to offer an alternative for cost-effective (approximately $2 per test) and end-user friendly device for household testing. Requiring as little as 2 L of finger-picked blood, the test can be performed at the household with just simple dilution and washings. With visual interpretation of numbers of test lines shown on the developed biosensor, it can be interpreted as easy as a urine pregnancy test, aided with scale of intensity provided. In summary, the developed HbA1c immunosensor has been tested to have high selectivity towards HbA1c, and is stable with reasonably good performance in clinical testing. Therefore, our developed HbA1c immunosensor has high potential to be an effective diabetic management tool to increase patient compliance and thus contain the progression of the diabetes.

Keywords: blood, glycated hemoglobin (HbA1c), lateral flow, type 2 diabetes mellitus

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Authors: Hamoud Al-Hadrami, Hossein Emadi, Athar Hussain

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Green hydrogen is quickly emerging as a new source of renewable energy for the world. Hydrogen production using water electrolysis is deemed as an environmentally friendly and safe source of energy for transportation and other industries. However, storing a high volume of hydrogen seems to be a significant challenge. Abandoned hydrocarbon reservoirs are considered as viable hydrogen storage options because of the availability of the required infrastructure such as wells and surface facilities. However, long-term wellbore integrity in these wells could be a serious challenge. Hydrogen reduces the compressive strength of a set cement if it gets in contact with the cement slurry. Also, mixing hydrogen with cement slurry slightly increases its density and rheological properties, which need to be considered to have a successful primary cementing operation.

Keywords: hydrogen, well bore integrity, clean energy, cementing

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Authors: Mohamed Khiatine, Amal Medjnoun, Ramdane Bahar

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The North Algeria is a highly seismic zone, as evidenced by the historical seismicity. During the past two decades, it has experienced several moderate to strong earthquakes. Therefore, the geotechnical engineering problems that involve dynamic loading of soils and soil-structure interaction system requires, in the presence of saturated loose sand formations, liquefaction studies. Bejaia city, located in North-East of Algiers, Algeria, is a part of the alluvial plain which covers an area of approximately 750 hectares. According to the Algerian seismic code, it is classified as moderate seismicity zone. This area had not experienced in the past urban development because of the different hazards identified by hydraulic and geotechnical studies conducted in the region. The low bearing capacity of the soil, its high compressibility and the risk of liquefaction and flooding are among these risks and are a constraint on urbanization. In this area, several cases of structures founded on shallow foundations have suffered damages. Hence, the soils need treatment to reduce the risk. Many field and laboratory investigations, core drilling, pressuremeter test, standard penetration test (SPT), cone penetrometer test (CPT) and geophysical down hole test, were performed in different locations of the area. The major part of the area consists of silty fine sand , sometimes heterogeneous, has not yet reached a sufficient degree of consolidation. The ground water depth changes between 1.5 and 4 m. These investigations show that the liquefaction phenomenon is one of the critical problems for geotechnical engineers and one of the obstacles found in design phase of projects. This paper presents an analysis to evaluate the liquefaction potential, using the empirical methods based on Standard Penetration Test (SPT), Cone Penetration Test (CPT) and shear wave velocity and numerical analysis. These liquefaction assessment procedures indicate that liquefaction can occur to considerable depths in silty sand of harbor zone of Bejaia.

Keywords: earthquake, modeling, liquefaction potential, laboratory investigations

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Authors: Olubiyi Johnson Ezekiel

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Basic science curriculum is an on-going effort towards developing the potential of manner to produce individuals in a holistic and integrated person, who are intellectually, spiritually, emotionally and physically balanced and harmonious. The main focus of this study is to determine the relationship between students’ achievement in junior school certificate examination (JSCE) and senior school basic science achievement test (SSBSAT) on the basis of all the components of basic science. The study employed the descriptive research of the survey type and utilized junior school certificate examination and senior school basic science achievement test(r = .87) scores as instruments. The data collected were subjected to Pearson product moment correlation, Spearman rank correlation, regression analysis and analysis of variance. The result of the finding revealed that the mean effects of the achievement in all the components of basic science on SSBSAT are significantly different from zero. Based on the results of the findings, it was concluded that the relationship between students’ achievement in JSCE and SSBSAT was weak and to achieve a unit increase in the students’ achievement in the SSBSAT when other subjects are held constant, we have to increase the learning of: -physics by 0.081 units; -chemistry by 0.072 units; -biology by 0.025 units and general knowledge by 0.097 units. It was recommended among others, that general knowledge aspect of basic science should be included in either physics or chemistry aspect of basic science.

Keywords: basic science curriculum, students’ achievement, science test, secondary school students

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Authors: John Trihatmoko, Luky Handoko

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A series of experimental program was undertaken to study the effect of curing temperature on the unconfined compression strength of bagasse ash (BA) - calcium carbide residue (CCR) stabilized organic clay (OC). A preliminary experiment was performed to get the physical properties of OC, and to get the optimum water content (OMC), the standard compaction test was done. The stabilizing agents used in this research was (40% BA + 60% CCR) . Then to obtain the best binder proportion, unconfined compression test was undertaken for OC + 3, 6, 9, 12 and 15% of binder with 7, 14, 21, 28 and 56 days curing period. The best quantity of the binder was found on 9%. Finally, to study the effect of curing temperature, the unconfined compression test was performed on OC + 9% binder with 7, 14, 21, 28 and 56 days curing time with 20O, 25O, 30O, 40O, and 50O C curing temperature. The result indicates that unconfined compression strength (UCS) of treated OC improve according to the increase of curing temperature at the same curing time. The improvement of UCS is probably due to the degree of cementation and pozzolanic reactions.

Keywords: curing temperature, organic clay, bagasse ash, calcium carbide residue, unconfined compression strength

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Authors: Mohd Anees Siddiqui, S. A. H. Jafri, Shahnawaz Alam

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Through this paper an attempt is made to review a special welding technology of friction stir welding (FSW) which is a solid-state joining. Friction stir welding is used for joining of two plates which are applied compressive force by using fixtures over the work table. This is a non consumable type welding technique in which a rotating tool of cylindrical shape is used. Process parameters such as tool geometry, joint design and process speed are discussed in the paper. Comparative study of Friction stir welding with other welding techniques such as MIG, TIG & GMAW is also done. Some light is put on several major applications of friction stir welding in different industries. Quality and environmental aspects of friction stir welding is also discussed.

Keywords: friction stir welding (FSW), process parameters, tool, solid state joining processes

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Authors: Abbas Shafiee, Mohammad Taghi Ahmadian, Maryam Hoviattalab

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The biomechanical behavior of brain tissue is needed for predicting the traumatic brain injury (TBI). Each year over 1.5 million people sustain a TBI in the USA. The appropriate coefficients for injury prediction can be evaluated using experimental data. In this study, an experimental setup on brain soft tissue was developed to perform unconfined compression tests at quasistatic strain rates ∈0.0004 s-1 and 0.008 s-1 and 0.4 stress relaxation test under unconfined uniaxial compression with ∈ 0.67 s-1 ramp rate. The fitted visco-hyperelastic parameters were utilized by using obtained stress-strain curves. The experimental data was validated using finite element analysis (FEA) and previous findings. Also, influence of friction coefficient on unconfined compression and relaxation test and effect of ramp rate in relaxation test is investigated. Results of the findings are implemented on the analysis of a human brain under high acceleration due to impact.

Keywords: brain soft tissue, visco-hyperelastic, finite element analysis (FEA), friction, quasistatic strain rate

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Authors: T. Sakamoto, S. Kainuma

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Firstly, in order to examine the influence of the remaining amount of the rust on the coating film durability, the accelerated deterioration tests were carried out. In order to prepare test specimens, uncoated steel plates were corroded by the Salt Spray Test (SST) prior to the accelerated deterioration tests, and then the prepared test specimens were coated by epoxy resin and phthalic acid resin each of which has different gas-barrier performance. As the result, it was confirmed that the under-film corrosion occurred in the area and the adjacency to great quantities of salt exists in the rust, and did not occurred in the specimen which was applied the epoxy resin paint after the surface preparation by the power tool. Secondly, in order to clarify the influence of the corrosive factors on the coating film durability, outdoor exposure tests were conducted for one year on actual steel bridge located at a coastal area. The tests specimens consist of coated corroded plates and the uncoated steel plates, and they were installed on the different structural members of the bridge for one year. From the test results, the uncoated steel plates which were installed on the underside of the member are easily corrosive and had highly correlation with the amount of salt in the rust. On the other hand, the most corrosive under-film steel was the vertical surface of the web plate. Thus, it was confirmed that under-film corrosion rate was not match with corrosion rate of the uncoated steel. Consequently, it is estimated that the main factors of under-film corrosion are gas-barrier property of coating film and corrosive factors such as water vapor and temperature. The salt which significantly corrodes the uncoated steel plate is not directly related to the under-film corrosion.

Keywords: accelerated deterioration test, coating durability, environmental factor, under-film corrosion

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Authors: Dalia Almaghaslah

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Design thinking approach; empathize, define, ideate prototype, test, implement, was used to assess outpatient experiences in two hospital pharmacies in the Asir region, Saudi Arabia. Semi-structured interviews were conducted with 40 patients. The data were analyzed using thematic analysis. The findings suggested that patients were generally satisfied with pharmaceutical services provided in both pharmacies. Pharmacists were found to have enough knowledge, good attitude, and efficient communication and counselling skills. Non-pharmacy-related factors such as cultural factors (gender segregation), long waiting times, uncomfortable waiting areas, lack of electronic prescribing, number waiting system were found to have a negative impact on patients' experiences and satisfaction. Prototypes will be used to test the effects of implementing the electronic system in Al -mahal hospital and to test changing the physical layout of the waiting area in Asir hospital.

Keywords: design thinking, hospital pharmacy, patient satisfaction, Saudi Arabia

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Authors: Hannah Patricia S., Louise Margarrette R., Josking Oliver L., Denisse Katrina C., Justine Kali O.

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Aims: In the Philippines, there has been an astronomical increase in the population of elderly sent to nursing home facilities which has been studied to induce despair and loss of self-worth. Nurses in institutionalized facilities generally care for the elderly. Although supportive group therapy has been explored to mend this psychological disparity, nursing research has limited published studies about this in the institutionalized setting. Hence, the study determined the effectiveness of supportive group therapy in depression, self-esteem and quality of life among institutionalized elderly. Methodology: A one-group pre-test-post-test design was conducted among 20-purposively selected institutionalized elderly after the Ethics Research Board approval. All eligible participants underwent the supportive group therapy after being subdivided into session groups. The Geriatric Depression Scale, which has a Cronbach’s alpha coefficient of 0.90; the Rosenberg Self-Esteem, which has a Cronbach’s alpha coefficient = 0.84; and the Older People Quality of Life, which has a Cronbach’s alpha coefficient =0.88, were utilized to measure depression, self-esteem, and quality of life, respectively. Descriptive statistics and Repeated Measures-Multivariate Analysis of Variance (RM-MANOVA) analyzed gathered data. Results: Results showed that the supportive group therapy significantly decreased post-test depression scores (F(1,19)=78.69,p=0.0001,partial η2=0.805), significantly improved post-test self-esteem score (F(1,19)=28.07,p=0.0001,partial η2=0.596), and significantly increased the post-test quality of life (F(1,19)=79.73,p=0.0001,partial η2=0.808) after the intervention has been rendered. Conclusion: Supportive group therapy is effective in alleviating depression and in improving self-esteem and quality of life among institutionalized elderly and can be utilized by nursing homes as an intervention to improve the over-all psychosocial status of elderly patients.

Keywords: supportive group therapy, institutionalized elderly, depression, self-esteem, quality of life

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Authors: B. Noruziaan, A. Shvarzman, R. Leahy

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An innovative flooring underlayment was produced and tested. The composite system is made of common OSB boards and a layer of eco-friendly non-cement gypsum based material (GeoGypTM). It was found that the shear bond between the two materials is sufficient to secure the composite interaction between the two. The very high compressive strength and relatively high tensile strength of the non-cement based component together with its high modulus of elasticity provides enough strength and stiffness for the composite product to cover wider spacing between the joists. The initial findings of this study indicate that with joist spacing as wide as 800 mm, the flooring system provides enough strength without compromising the serviceability requirements of the building codes.

Keywords: Composite, floor deck, gypsum based, lumber joist, non-cement, oriented strandboard, shear bond

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Authors: Zoltan Horvath, Dora Nagy

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In this research, it was examined whether individual COVID variants cause differences in the lactate curve of cyclists. After all, the virus variants attacked different organs in our body during the infections. During our tests, we used a traditional lactate step test, the results of which were compared with the values before the infection. In the tests, it has been proven that different virus variants show unique lactate curves. In this way, based on the lactate curve, it is possible to identify which variant caused the disease. Thanks to this, it has been shorten the return time, because we can apply the best return protocol after infection to the competitors.

Keywords: COVID-Sars19, lactate, virus mutation, lactate profile

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Authors: Raghabendra Yadav, Baochun Chen, Huihui Yuan, Zhibin Lian

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Pseudo-dynamic test (PDT) method is an advanced seismic test method that combines loading technology with computer technology. Large-scale models or full scale seismic tests can be carried out by using this method. CFST-RC columns are used in civil engineering structures because of their better seismic performance. A CFST-RC column is composed of four CFST limbs which are connected with RC web in longitudinal direction and with steel tube in transverse direction. For this study, a CFST-RC pier is tested under Four different earthquake time histories having scaled PGA of 0.05g. From the experiment acceleration, velocity, displacement and load time histories are observed. The dynamic magnification factors for acceleration due to Elcentro, Chi-Chi, Imperial Valley and Kobe ground motions are observed as 15, 12, 17 and 14 respectively. The natural frequency of the pier is found to be 1.40 Hz. The result shows that this type of pier has excellent static and earthquake resistant properties.

Keywords: bridge pier, CFST-RC pier, pseudo dynamic test, seismic performance, time history

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Authors: Olesia Mikhailova, Pavel Rovnaník

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In the present work, metakaolin-based geopolymer including different polymer admixtures was studied. Different types of commercial polymer admixtures VINNAPAS^® and polyethylene glycol of different relative molecular weight were used as polymer admixtures. The main objective of this work is to investigate the influence of different types of admixtures on the properties of metakaolin-based geopolymer mortars considering their different dosage. Mechanical properties, such as flexural and compressive strength were experimentally determined. Also, study of the microstructure of selected specimens by using a scanning electron microscope was performed. The results showed that the specimen with addition of 1.5% of VINNAPAS^® 7016 F and 10% of polyethylene glycol 400 achieved maximum mechanical properties.

Keywords: geopolymer, mechanical properties, metakaolin, microstructure, polymer admixtures, porosity

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Authors: Han Xiao, Ruan Qi, Zhang Lei, Qi Yan

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Space environment simulator is a facility used to conduct thermal test for spacecraft, and vacuum vessel is the main body of it. According to the requirements for thermal tests of the spacecraft and its solar array panels, the primary vessel and the side vessels are designed to be a combinative structure connected with aperture, which ratio reaches 0.7. Since the vacuum vessel suffers 0.1MPa external pressure during the process of thermal test, in order to ensure the simulator’s reliability and safety, it’s necessary to calculate the vacuum vessel’s intensity and stability. Based on the impact of large openings to vacuum vessel structure, this paper explored the reinforce design and analytical way of vacuum vessel with large openings, using a large space environment simulator’s vacuum vessel design as an example. Tests showed that the reinforce structure is effective to fulfill the requirements of external pressure and the gravity. This ensured the reliability of the space environment simulator, providing a guarantee for developing the spacecraft.

Keywords: vacuum vessel, large opening, space environment simulator, structure design

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Authors: Natthawut Arin

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In forensic contexts, competency to stand trial assessments are the most common referrals. The defendants may attempt to endorse psychopathology symptoms and feign incompetent. Coaching, which can be teaching them test-taking strategies to avoid detection of psychopathological symptoms feigning. Recently, the Symptom Validity Testings (SVTs) were created to detect feigning. Moreover, the works of the literature showed that the effects of coaching on SVTs may be more robust to the effects of coaching. Thai Symptom Validity Test (SVT-Th) was designed as SVTs which demonstrated adequate psychometric properties and ability to classify between feigners and honest responders. Thus, the current study to examine the utility as the robustness of SVT-Th in the detection of feigned psychopathology. Participants consisted of 120 were recruited from undergraduate courses in psychology, randomly assigned to one of three groups. The SVT-Th was administered to those three scenario-experimental groups: (a) Uncoached group were asked to respond honestly (n=40), (b) Symptom-coached without warning group were asked to feign psychiatric symptoms to gain incompetency to stand trial (n=40), while (c) Test-coached with warning group were asked to feign psychiatric symptoms to avoid test detection but being incompetency to stand trial (n=40). Group differences were analyzed using one-way ANOVAs. The result revealed an uncoached group (M = 4.23, SD.= 5.20) had significantly lower SVT-Th mean scores than those both coached groups (M =185.00, SD.= 72.88 and M = 132.10, SD.= 54.06, respectively). Classification rates were calculated to determine the classification accuracy. Result indicated that SVT-Th had overall classification accuracy rates of 96.67% with acceptable of 95% sensitivity and 100% specificity rates. Overall, the results of the present study indicate that the SVT-Th yielded high adequate indices of accuracy and these findings suggest that the SVT-Th is robustness against coaching.

Keywords: incompetency to stand trial, coaching, robustness, classification accuracy

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Authors: Christian Neunzig, Simon Fahle, Jürgen Schulz, Matthias Möller, Bernd Kuhlenkötter

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The increasing use of deep learning applications in production is becoming a competitive advantage. Predictive quality enables the assurance of product quality by using data-driven forecasts via machine learning models as a basis for decisions on test results. The use of real Bosch production data along the value chain of hydraulic valves is a promising approach to classifying the leakage of directional valves.

Keywords: artificial neural networks, classification, hydraulics, predictive quality, deep learning

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Authors: Agajie Likie Bogale, Tilahun Teklehaymanot, Getnet Mitike Kassie, Girmay Medhin, Jemal Haidar Ali, Nega Berhe Belay

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Objectives: The aim of this study is to evaluate the performance of visual inspection using acetic acid compared with HPV DNA testing among women living with HIV in Ethiopia. Methods: Acomparative cross-sectional study was conducted to address the aforementioned objective. Data were collected from January to October 2021 to compare the performance of these two screening modalities. Trained clinicians collected cervical specimens and immediately applied acetic acid for visual inspection. The HPV DNA testing was done using Abbott m2000rt/SP by trained laboratory professionals in accredited laboratories. A total of 578 HIV positive women with age 25-49 years were included. Results: Test positivity was 8.9% using VIA and 23.3% using HPV DNA test. The sensitivity and specificity of the VIA test were 19.2% and 95.1%, respectively, while the positive and negative predictive values of the VIA test were 54.4% and 79.4%, respectively. The strength of agreement between the two screening methods was poor (k=0.184), and the area under the curve was 0.572. The burden of genetic distribution of high risk HPV16 was 3.8%, and mixed HPV16& other HR HPV was 1.9%. Other high risk HPV types were predominant in this study (15.7%). Conclusion: The high positivity result using HPV DNA testing compared with VIA, and low sensitivity of VIA are indicating that the implementation of HPV DNA testing as the primary screening strategy is likely to reduce cervical cancer cases and deaths of women in the country.

Keywords: cervical cancer screening, HPV DNA, VIA, Ethiopia

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Authors: D. L. Tambe, S. Dighe Nachiket

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Objective: Depression is a common but serious illness and the phenothiazine derivatives shows prominent effect against the depression hence work was undertaken to validate this use scientifically. Material and Methods: Synthesis of phenothiazine derivatives are done by the substitution of various groups, but the basic scheme of synthesis is started with synthesis of 4-(Cyclohexylidene) Benzoic acid using PABA. After that with the further six step of synthesis of 3-(10H-phenothiazin-2-yl)-N, 5-diphenyl-4H-1, 2, 4-triazol-4-amine is done which is final product. Antidepressant activity of all the synthesized compounds was evaluated by despair swim test by using Sprague Dawley Rats. Standard drug imipramine was used as the control. In the despair swim test, all the synthesized derivatives showed antidepressant activity. Results: Among the all phenothiazine derivatives four compounds (6.6-7.2 (14H –phenyl ), 9.43 (1H OH), 8.50 (1H NH phenothiazine),6.85-8.21(14H phenyl), 8.50 (1H NH phenothiazine), 11.82 (1H – OH), 6.6-7.2 (8H –phenyl ), 9.43 (1H OH), 8.50 (1H NH phenothiazine), 4.2 (1H NH) and 6.85-8.21(8H phenyl), 8.50 (1H NH phenothiazine), 3.9 (1H NH) 11.82 (1H – OH) showed significant antidepressant activity comparing with control drug imipramine. Conclusion: Various Novel phenothiazine derivatives show more potent antidepressant activity and it plays more beneficial role in human health for the treatment of depression.

Keywords: antidepressant activities, despair swim test, phenothiazine, Sprague Dawley Rats

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Authors: Adam M. Pitz, Gillian L. Phillipson, Jayant E. Khanolkar, Andrew M. Middleton

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New emerging evidence suggests that the nose is the predominant route for entry of the SARS-CoV-2 virus into the host. A virucidal suspension test (conforming in principle to the European Standard EN14476) was conducted to determine whether a commercial liquid gel intranasal spray containing 1% of the mucoadhesive hydroxypropyl methylcellulose (HPMC) could inhibit the cellular infectivity of the SARS-CoV-2 coronavirus. Virus was added to the test product samples and to controls in a 1:8 ratio and mixed with one part bovine serum albumin as an interfering substance. The test samples were pre-equilibrated to 34 ± 2°C (representing the temperature of the nasopharynx) with the temperature maintained at 34 ± 2°C for virus contact times of 1, 5 and 10 minutes. Neutralized aliquots were inoculated onto host cells (Vero E6 cells, ATCC CRL-1586). The host cells were then incubated at 36 ± 2°C for a period of 7 days. The residual infectious virus in both test and controls was detected by viral-induced cytopathic effect. The 50% tissue culture infective dose per mL (TCID50/mL) was determined using the Spearman-Karber method with results reported as the reduction of the virus titer due to treatment with test product, expressed as log10. The controls confirmed the validity of the results with no cytotoxicity or viral interference observed in the neutralized test product samples. The HPMC formulation reduced SARS-CoV-2 titer, expressed as log10TCID50, by 2.30 ( ± 0.17), 2.60 ( ± 0.19), and 3.88 ( ± 0.19) with the respective contact times of 1, 5 and 10 minutes. The results demonstrate that this 1% HPMC gel formulation can reduce the cellular infectivity of the SARS-CoV-2 virus with an increasing viral inhibition observed with increasing exposure time. This 1% HMPC gel is well tolerated and can reside, when delivered via nasal spray, for up to one hour in the nasal cavity. We conclude that this intranasal gel spray with 1% HPMC repeat-dosed every few hours may offer an effective preventive or early intervention solution to limit the transmission and impact of the SARS-CoV-2 coronavirus.

Keywords: hydroxypropyl methylcellulose, mucoadhesive nasal spray, respiratory viruses, SARS-CoV-2

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Authors: Mohammad Saberian, Mohammad Ali Rahgozar, Reza Porhoseini

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Peat soil is formed naturally through the accumulation of organic matter under water and it consists of more than 75% organic substances. Peat is considered to be in the category of problematic soil, which is not suitable for construction, due to its high compressibility, high moisture content, low shear strength, and low bearing capacity. Since this kind of soil is generally found in many countries and different regions, finding desirable techniques for stabilization of peat is absolutely essential. The purpose of this paper is to review the various techniques applied for stabilizing peat soil and discuss outcomes of its improved mechanical parameters and strength properties. Recognizing characterization of stabilized peat is one of the most significant factors for architectural structures; as a consequence, various strategies for stabilization of this susceptible soil have been examined based on the depth of peat deposit.

Keywords: peat soil, stabilization, depth, strength, unconfined compressive strength (USC)

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Authors: S. Yousefi Oderji, B. Chen

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According to the ASTM C1018 toughness index method, the single and combined toughness effects of copper coated steel fiber and polypropylene (pp) fiber on reactive powder concrete (RPC) were investigated. Through flexural toughness test of RPC with different fiber volume dosages, the corresponding load-deflection curves were also drawn. Test results indicate that the binary combination of fibers provide the best flexural toughness, and improve the post-peak load-deflection characteristics of RPC. However, the single effect of pp fibers was not pronounced on improving the flexural toughness of RPC.

Keywords: RPC, PP, flexural toughness, toughness index

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Authors: Maciej Szelag

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The discovery of the carbon nanotubes (CNT), has led to a breakthrough in the material engineering. The CNT is characterized by very large surface area, very high Young's modulus (about 2 TPa), unmatched durability, high tensile strength (about 50 GPa) and bending strength. Their diameter usually oscillates in the range from 1 to 100 nm, and the length from 10 nm to 10-2 m. The relatively new approach is the CNT’s application in the concrete technology. The biggest problem in the use of the CNT to cement composites is their uneven dispersion and low adhesion to the cement paste. Putting the nanotubes alone into the cement matrix does not produce any effect because they tend to agglomerate, due to their large surface area. Most often, the CNT is used as an aqueous suspension in the presence of a surfactant that has previously been sonicated. The paper presents the results of investigations of the basic physical properties (apparent density, shrinkage) and mechanical properties (compression and tensile strength) of cement paste with the addition of the multiwall carbon nanotubes (MWCNT). The studies were carried out on four series of specimens (made of two different Portland Cement). Within each series, samples were made with three w/c ratios – 0.4, 0.5, 0.6 (water/cement). Two series were an unmodified cement matrix. In the remaining two series, the MWCNT was added in amount of 0.1% by cement’s weight. The MWCNT was used as an aqueous dispersion in the presence of a surfactant – SDS – sodium dodecyl sulfate (C₁₂H₂₅OSO₂ONa). So prepared aqueous solution was sonicated for 30 minutes. Then the MWCNT aqueous dispersion and cement were mixed using a mechanical stirrer. The parameters were tested after 28 days of maturation. Additionally, the change of these parameters was determined after samples temperature loading at 250°C for 4 hours (thermal shock). Measurement of the apparent density indicated that cement paste with the MWCNT addition was about 30% lighter than conventional cement matrix. This is due to the fact that the use of the MWCNT water dispersion in the presence of surfactant in the form of SDS resulted in the formation of air pores, which were trapped in the volume of the material. SDS as an anionic surfactant exhibits characteristics specific to blowing agents – gaseous and foaming substances. Because of the increased porosity of the cement paste with the MWCNT, they have obtained lower compressive and tensile strengths compared to the cement paste without additive. It has been observed, however, that the smallest decreases in the compressive and tensile strength after exposure to the elevated temperature achieved samples with the MWCNT. The MWCNT (well dispersed in the cement matrix) can form bridges between hydrates in a nanoscale of the material’s structure. Thus, this may result in an increase in the coherent cohesion of the cement material subjected to a thermal shock. The obtained material could be used for the production of an aerated concrete or using lightweight aggregates for the production of a lightweight concrete.

Keywords: cement paste, elevated temperature, mechanical parameters, multiwall carbon nanotubes, physical parameters, SDS

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Authors: Svanik Garg

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Static Test Pads are stationary mechanisms that hold a solid rocket motor, measuring the different parameters of its operation including thrust and temperature to better calibrate it for launch. This paper outlines a specific STP designed to test high powered rocket motors with a thrust upwards of 4000N and limited to 6500N. The design includes a specific portable mechanism with cost an integral part of the design process to make it accessible to small scale rocket developers with limited resources. Using curved surfaces and an ergonomic design, the STP has a delicately engineered façade/case with a focus on stability and axial calibration of thrust. This paper describes the design, operation and working of the STP and its widescale uses given the growing market of aviation enthusiasts. Simulations on the CAD model in Fusion 360 provided promising results with a safety factor of 2 established and stress limited along with the load coefficient A PCB was also designed as part of the test pad design process to help obtain results, with visual output and various virtual terminals to collect data of different parameters. The circuitry was simulated using ‘proteus’ and a special virtual interface with auditory commands was also created for accessibility and wide-scale implementation. Along with this description of the design, the paper also emphasizes the design principle behind the STP including a description of its vertical orientation to maximize thrust accuracy along with a stable base to prevent micromovements. Given the rise of students and professionals alike building high powered rockets, the STP described in this paper is an appropriate option, with limited cost, portability, accuracy, and versatility. There are two types of STP’s vertical or horizontal, the one discussed in this paper is vertical to utilize the axial component of thrust.

Keywords: static test pad, rocket motor, thrust, load, circuit, avionics, drag

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Authors: Wang Guangda, Ma Jun, Zhao Caiqi, Pan Rui

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Wind load is the main control load of large statue structures. Due to the irregular plane and elevation and uneven outer contour, statues’ shape coefficient can not pick up from the current code. Currently a common practice is based on wind tunnel test. But this method is time-consuming and high cost. In this paper, based on the fundamental theory of CFD, using fluid dynamics software of Fluent 15.0, a few large statue structure of 40 to 70m high, which are located in china , including large fairy statues and large Buddha statues, are analyzed by numerical wind tunnel. The results are contrasted with the recommended values in load code and the wind tunnel test results respectively. Results show that the shape coefficient has a good reliability by the numerical wind tunnel method of this kind of building. This will has a certain reference value of wind load values for large statues’ structure.

Keywords: large statue structure, shape coefficient, irregular structure, wind tunnel test, numerical wind tunnel simulation

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Authors: Shijie Liu, Jehnming Lin

Abstract:

This study mainly discussed the mechanical properties of selective laser sintered 304L stainless steel powder specimen. According to a single layer specimen sintering, the microstructure and porosity were observed to find out the proper sintering parameters. A multi-layer sintering experiment was conducted. Based on the microstructure and the integration between layers, the suitable parameters were found out. Finally, the sintered specimens were examined by metallographical inspection, hardness test, tensile test, and surface morphology measurement. The structure of the molten powder coated with unmelted powder was found in metallographic test. The hardness of the sintered stainless steel powder is greater than the raw material. The tensile strength is less than the raw material, and it is corresponding to different scanning paths. The specimen will have different patterns of cracking. It was found that the helical scanning path specimen will have a warpage deformation at the edge of the specimen. The S-scan path specimen surface is relatively flat.

Keywords: laser sintering, sintering path, microstructure, mechanical properties

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Authors: Hui-Fang Lee, Hsuan-Jung Hsieh, Wen-Chi Lu, Meng-Chu Liu

Abstract:

The purpose of the study was to examine abnormal BMI students of Chien Hsin University of Science and Technology, implement teaching aerobics course through elementary and advanced curriculum design, dietary education and three-day dietary record, analyze participant fitness improvement, an 10-week course as well as pre-test and post-test were carried out to evaluate the effect of the aerobics course on the fitness ability. The actual participate elementary and advanced courses each of 40 people, with low participation deduction course unfinished fitness testing, access to elementary curriculum valid samples 35 (87.5%) people, advanced courses valid samples 38(95%) people, 16 students participated in two consecutive courses. The fitness activities included sit-bending, one-minute sit-ups, standing long jump, and three minutes to board the stage. Analysis and comparison to the average three-day dietary record difference, an independent samples t-test was conducted to analyze the differences in the four activities between pre-test and post-test. The results showed that the elementary course had significant effects on females’ sit-bending and one minute sit-ups, the females also had high fat intake in three-day dietary record. The advanced course had significant effects on males’ sit-bending and on females’ BMI, sit-bending and standing long jump, males and females in three-day dietary record carbohydrate intake slightly low, slightly higher protein and fat intake. In conclusion, aerobics course teaching, dietary education and three-day, dietary record implementation can significantly enhance the physical fitness indicators, and continued to participate in advanced courses better. In the practice of sport should be the future course planning elementary and advanced courses, while introducing dietary education, achieve concrete results in improving physical fitness.

Keywords: physical fitness, aerobics course, dietary education, three-day dietary record

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Authors: Ivana Hrebickova, Maria Sevcikova, Romana Slamberova

Abstract:

The present study was aimed at evaluation of cognitive changes following scheduled neonatal methamphetamine exposure in combination with long-term exposure in adulthood of female Wistar rats. Pregnant mothers were divided into two groups: group with indirect exposure (methamphetamine in dose 5 mg/ml/kg, saline in dose 1 ml/kg) during early lactation period (postnatal day 1–11) - progeny of these mothers were exposed to the effects of methamphetamine or saline indirectly via the breast milk; and the second group with direct exposure – all mothers were left intact for the entire lactation period, while progeny was treated with methamphetamine (5 mg/ml/kg) by injection or the control group, which was received needle pick (shame, not saline) at the same time each day of period of application (postnatal day 1–11). Learning ability and memory consolidation were tested in the Morris Water Maze, which consisted of three types of tests: ‘Place Navigation Test ‘; ‘Probe Test ‘; and ‘Memory Recall Test ‘. Adult female progeny were injected daily, after completion last trial with saline or methamphetamine (1 mg/ml/kg). We compared the effects of indirect/direct neonatal methamphetamine exposure and adult methamphetamine treatment on cognitive function of female rats. Statistical analyses showed that neonatal methamphetamine exposure worsened spatial learning and ability to remember the position of the platform. The present study demonstrated that direct methamphetamine exposure has more significant impact on process of learning and memory than indirect exposure. Analyses of search strategies (thigmotaxis, scanning) used by females during the Place Navigation Test and Memory Recall Test confirm all these results.

Keywords: methamphetamine, Morris water maze, neonatal exposure, strategies, Wistar rats

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Authors: Joshi Rajiv, Shah Priyank, Thavkar Amit, Rohira Poonam, Mehta Suyog

Abstract:

Topical formulation containing minoxidil and finasteride helps hair growth in the treatment of male androgenetic alopecia. The objective of this study is to compare the irritation potential of three conventional formulations of minoxidil 5% + finasteride 0.1% topical solution of in human patch test. The study was a single centre, double blind, non-randomized controlled study in 53 healthy adult Indian subjects. Occlusive patch test for 24 hours was performed with three formulations of minoxidil 5% + finasteride 0.1% topical solution. Products tested included aqueous based minoxidil 5% + finasteride 0.1% (AnasureTM-F, Sun Pharma, India – Brand A), lipid based minoxidil 5% + finasteride 0.1% (Brand B) and aqueous based minoxidil 5% + finasteride 0.1% (Brand C). Isotonic saline 0.9% and 1% w/w sodium lauryl sulphate were included as negative control and positive control respectively. Patches were applied and removed after 24 hours. The skin reaction was assessed and clinically scored 24 hours after the removal of the patches under constant artificial daylight source using the Draize scale (0-4 points scale for erythema/dryness//wrinkles and for oedema). Follow-up was scheduled after one week to confirm recovery for any reaction. A combined mean score up to 2.0/8.0 indicates a product is “non-irritant” and a score between 2.0/8.0 and 4.0/8.0 indicates “mildly irritant” and a score above 4.0/8.0 indicates “irritant”. The procedure of the patch test followed the principles outlined by the Bureau of Indian Standards (BIS) (IS 4011:2018; Methods of Test for safety evaluation of Cosmetics-3rd revision). Fifty three subjects with mean age 31.9 years (25 males and 28 females) participated in the study. The combined mean score ± standard deviation were: 0.06 ± 0.23 (Brand A), 0.81 ± 0.59 (Brand B), 0.38 ± 0.49 (Brand C), 2.92 ± 0.47 (positive control) and 0.0 ± 0.0 (Negative control). This means the score of Brand A (Sun Pharma product) was significantly lower than that of Brand B (p=0.001) and that of Brand C (p=0.001). The combined mean erythema score ± standard deviation were: 0.06 ± 0.23 (Brand A), 0.81 ± 0.59 (Brand B), 0.38 ± 0.49 (Brand C), 2.09 ± 0.4 (Positive control) and 0.0 ± 0.0 (Negative control). The mean erythema score of Brand A was significantly lower than Brand B (p=0.001) and that of Brand C (p=0.001). Any reaction observed at 24hours after patch removal subsided in a week. All the three topical formulations of minoxidil 5% + finasteride 0.1% were non-irritant. Brand A of minoxidil 5% + finasteride 0.1% (Sun Pharma) was found to be the least irritant than Brand B and Brand C based on the combined mean score and mean erythema score in the human patch test as per the BIS, IS 4011:2018

Keywords: erythema, finasteride, irritation, minoxidil, patch test

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Authors: Kasbparast Mehdi, Hassani Zainab

Abstract:

Aim: The purpose of this research was to investigate the effectiveness of therapeutical sensorimotor exercise. The statistical population of women who were diagnosed with patellofemoral pain syndrome by a doctor and were between the ages of 35 and 45 and registered for the first time in a sports club in the 4th district of Tehran, 30 people by random sampling and according to The include and exclude criteria were selected and divided into 2 equal control and experimental and homogeneous groups (in terms of height, weight and BMI).In both control and experimental groups, the pain was measured using a Visual Analog Scale(VAS) functionality was measured using the step-down test and quality of life was measured using a World Health Organization Quality of Life Scale (WHOQOL-BREF) (pre-test). Then, only the experimental group performed sensorimotor exercises for 12 weeks and 3 sessions each week, a total of 24 sessions and each session for 1 hour, and during this period, the control group only continued their daily activities. After the end of the training period, the desired factors were evaluated again (post-test) in the same way as the pre-test was done for them (experimental group and control group), with the same quality. Findings: The statistical results showed that in the experimental group, the amount of pain, function and quality of life had a statistical improvement (P≤0.05). Conclusion: In general conclusion, it can be stated that using sensorimotor exercises not only improved functionality and quality of life but also reduced the amount of pain in people with patellofemoral pain syndrome.

Keywords: pain, PFPS, sensori motor training, functionality

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