Behavior of Post-Tensioned Concrete Girders Subject to Partially Strand Damage and Strengthened by NSM-CFRP Composites

Studies on the flexural behavior of post-tensioned beams subjected to strand damage and strengthened with near-surface mounted (NSM) technique using carbon fiber-reinforced polymer (CFRP) are limited and fail to examine the effect of CFRP laminates on strand strain and strengthening efficiency systematically. Furthermore, a design approach for UPC structures in existing design guidelines for FRP strengthening techniques is lacking. Hence, the behavior of post-tensioned beams strengthened with NSM-CFRP laminates after partial strand damage is investigated in this study. The testing program consists of seven post-tensioned beams strengthened by NSM-CFRP laminates with three partial strand damage ratios (14.3% symmetrical damage, 14.3% asymmetric damage, and 28.6% symmetrical damage). The experimental results showed that the use of CFRP laminates significantly increases the flexural capacity by up to 17.4 to 20.4%, corresponding to a strand damage ratio of 14.3 and 28.6%, respectively, enhances the stiffness, and reduces strand strain by up to 15.8 to 22.2%. However, the flexural stiffness of strengthened beams during serviceability phases is critical as strand damage ratios increase. Additionally, semi-empirical equations were proposed to predict the actual strain of unbonded strands whilst considering the effects of CFRP laminates. The suggested equations provide accurate predictions with little variance. Doi: 10.28991/CEJ-2022-08-07-013 Full Text: PD

Finite Element Analysis of Concrete Beam under Flexural Stresses Using Meso-Scale Model

Two dimensional meso-scale concrete modeling was used in finite element analysis of plain concrete beam subjected to bending. The plane stress 4-noded quadrilateral elements were utilized to model coarse aggregate, cement mortar. The effect of aggregate fraction distribution, and pores percent of the total area – resulting from air voids entrapped in concrete during placement on the behavior of plain concrete beam in flexural was detected. Aggregate size fractions were randomly distributed across the profile area of the beam. Extended Finite Element Method (XFEM) was employed to treat the discontinuities problems result from double phases of concrete and cracking that faced during the finite element analysis of concrete beam. Cracking was initiated at a small notch located at the middle of the bottom face of the concrete beam. The response of plain concrete beam subjected to pure bending via two point load application was detected using (XFEM) analysis of meso-scale concrete model. Assuming full bond between aggregate particles, and mortar at interfacial zone, the flexural strength of plain concrete beam is increased when aggregate particles size is increased, so that bending and shear stress were affected by void percentage and aggregate particles distribution. The maximum deflection at midspan was increased when the aggregate particles size decreases

Structural Strengthening of Insufficiently Designed Reinforced Concrete T-Beams using CFRP Composites

This study aims to compare the response of reinforced concrete (RC) T-beams strengthened with carbon fibre-reinforced polymer (CFRP) composite with that of non-strengthened control beams when subjected to monotonic two-point loading until failure for flexural once and shear again. The experimental programme tested eight RC T-beams, which included two reference beams without strengthening and six strengthened beams. The eight beams were divided into two main groups according to strengthening (flexural and shear). Experimental analysis was performed to study the effect of the CFRP laminate width in the flexural group and the spacing of CFRP U-wrap sheets in the shear group on the ultimate load capacity, load-strain relationship, and load-deflection relationship. Results show that increasing the width of the CFRP laminate in the flexural group improves the ultimate strengths to approximately 9.5%, 35%, and 41% for beams with CFRP laminate widths of 50, 100, and 150 mm, respectively, compared with the reference non-strengthened beam. The stiffness of the beams increases in direct proportion to the width of the CFRP laminate. In the meantime, decreasing the spacing of the CFRP laminate in the shear group increases the ultimate strengths to approximately 13.2%, 17.7%, and 23.5% for beams with CFRP U-wrap sheet spacings of 166, 125, and 100 mm, respectively, compared with the reference non-strengthened beam. Therefore, the spacing of the CFRP sheet is inversely proportional to the stiffness of the beam. Doi: 10.28991/CEJ-2023-09-08-05 Full Text: PD

Biofuels (Bioethanol, Biodiesel,and Biogas) from Lignocellulosic Biomass :A Review

الانبعاثات الغازية الناتجة عن استخدام الوقود الأحفوري عند حرقها تسبب زيادة في الاحتباس الحراري. لذلك، من أجل التنمية المستدامة، ينبغي إيلاء الاعتبار لإنتاج طاقات بديلة خضراء يمكن إنتاجها من المخلفات الحيوية المتاحة من مخلفات الطعام أو المخلفات الزراعية أو مخلفات مصانع الأغذية. يعد تحويل النفايات إلى طاقات بديلة أو وقود حيوي جانبًا إيجابيًا نظرًا للزيادة المستمرة في النفايات التي تخلق مشاكل بيئية. ان الأساليب التقليدية للتخلص من النفايات مثل مدافن النفايات أو الحرق تنتج غازات الاحتباس الحراري. إنتاج الوقود الحيوي من مواد اللجينية الخلوية التي تحتوي على بوليمرات الكربوهيدرات واللجنين المكونين اللذان يعتبران بمثابة وسيط لإنتاج المواد الكيميائية والوقود الحيوي والبيوميثان وهيدروجين حيوي كبدائل للوقود الأحفوري. في هذا المقال، قمنا بمراجعة طرق المعالجة المختلفة والتقنية الحديثة التي يمكن لها ان تحسن التحلل للكتلة الحيوية السليلوزية المختلفة (النفايات الزراعية، مخلفات الطعام، النفايات البلدية، ومخلفات الحيوانات في) وتحويلها إلى وقود حيوي (الإيثانول، الديزل الحيوي، الغاز الحيوي). يتم اعتماد اختيار المعالجة المسبقة للمواد السليلوزية على التكلفة الاقتصادية لإنتاج الوقود الحيوي، وقد اجريت العديد من الدراسات في جميع أنحاء العالم من اجل تطوير تكنولوجيا إنتاج الطاقة البديلة (الوقود الحيوي) كبديل للوقود الأحفوري عن طريق تقليل التكلفة الاقتصادية لمعالجة النفايات البيولوجية.Gaseous emissions are from the use of fossil fuels when burned to cause an increase in global warming. Therefore, for sustainable development, consideration should be given to the production of green alternative energies that can be produced from the bio-waste available from food residues, agricultural residues or food factory residues. Converting waste to alternative energies or biofuels is a positive aspect due to the continuous increase in waste that creates environmental problems and traditional methods of waste disposal such as landfills or incineration produce gas.  Biofuels production from lignocelluloses materials which are containing carbohydrate polymers and lignin, both of these components considered as a feedstock for produce chemical material, biofuel, biomethane, biohydrogen as alternatives of fossil fuel.  In this paper, the researcher reviewed different pretreatments methods and recent technology that can be enhanced degradable of various biowaste or lignocelluloses biomass (agricultural waste, food residue, municipal wastes, and animal waste of) and conversion to biofuel (bioethanol, biodiesel, and biogas). The selection of the pretreatment of cellulosic material depends on the economic cost of producing biofuels; so many researchers around the world were trying to develop alternative energy (biofuel) production technology as an alternative to fossil fuels by reducing the economic cost of biowaste pretreatment

”Hakijat kokivat, että anonyymirekrytointi oli aidosti yhdenvertainen” : Suomalaisten kaupunkien kokemuksia anonyymirekrytoinnista

Anonyymirekrytointi on suhteellisen uusi rekrytointimenetelmä, jonka tavoitteena on edistää yhdenvertaisuutta ja vähentää rekrytointisyrjintää. Suomessa rekrytointisyrjintää esiintyy yllättävänkin paljon, joten syrjintää vähentävät tiedot, menetelmät ja tavat ovat tervetulleita, ja niitä on syytä tutkia. Perinteiseen rekrytointiin verrattuna anonyymirekrytoinnissa ei näy henkilöön viittaavia tietoja, kuten nimeä, kuvaa, ikää, sukupuolta ja äidinkieltä. Tarkoituksena on auttaa keskittymään tehtävän kannalta olennaisiin seikkoihin. Tutkimus päätettiin tehdä laadullisena tutkimuksena. Laadullinen tutkimus pyrkii tuottamaan uutta informaatiota, joten se sopii aiheeseen mainiosti. Anonyymirekrytoinnin ollessa suhteellisen uusi rekrytointimenetelmä, aiheesta riittää tutkittavaa. Tämän pro gradun tarkoituksena on saada yleisesti informaatiota anonyymirekrytoinnista, sen hyödyistä, haasteista ja suomalaisten kaupunkien kokemuksista anonyymirekrytoinnista. Tutkimukseen osallistui kuusi kaupunkia ja 11 haastateltavaa. Kaikki haastateltavat työskentelevät rekrytoinnin parissa, ja jokaisella on kokemusta anonyymirekrytoinnista. Tutkielmassa vastataan seuraaviin tutkimuskysymyksiin: Millaisia kokemuksia julkisilla organisaatioilla on anonyymirekrytoinnista? Mitkä ovat anonyymirekrytoinnin hyödyt ja haasteet organisaatioiden kokemusten mukaan? Miten organisaation monimuotoisuus on edistynyt anonyymirekrytoinnin avulla? Miksi anonyymirekrytoinnin käyttö on edelleen vähäistä? Anonyymirekrytointia tutkittaessa moni asia oli linjassa teorian ja tutkimuksen tulosten välillä. Anonyymirekrytointi nähdään tapana edistää yhdenvertaisuutta ja tasa-arvoa, mutta sitä ei kuitenkaan nähdä täysin aukottamana ja täydellisenä menetelmänä. Tämän tutkielman tulosten perusteella anonyymirekrytoinnilla on paikkansa rekrytoinneissa ja siitä povataan jopa rekrytointien päämenetelmää. Tutkimushaastatteluissa esiintyi teoriaosuuteen verrattuna monipuolisemmin anonyymirekrytoinnin hyötyjä, haittoja ja kehitysehdotuksia, joihin tässä tutkimuksessa paneudutaan. Yhdenvertaisuuden edistäminen, työnantajakuvan parantuminen ja hakijoiden vertailemisen helpottuminen ovat esimerkkejä anonyymirekrytoinnin hyödyistä. Yleisimmät koetut haasteet olivat hankaluus taata täydellinen anonymiteetti, rekrytointijärjestelmien kyky tukea anonyymiä rekrytointimenetelmää sekä hakijoiden ja työnantajan välisen yhteydenpidon hankaloituminen ennen haastatteluvaihetta. Anonyymirekrytointia kohtaan koettiin olevan myös paljon ennakkoluuloja, muun muassa siitä, että se hidastaisi rekrytointiprosessia ja lisäisi työmäärää. Anonyymirekrytointia kokeilleet kumosivat kuitenkin nämä väitteet

Miliary Bovine Tuberculosis in Buffaloes in Al-Muthanna Governorate, Iraq

Background: Bubalus bubalis (river buffaloes) are widely distributed in the southern marshes of Iraq. This study intends to record a case of miliary tuberculosis in buffalo for the first time in Al Muthanna abattoir, Iraq, with its clinical, gross, and histopathological findings and microbiological investigations. Case Description: Ten years old buffalo showed chronic cough, infertility, emaciation, debilitation, lower milk production, loss of weight, and loss of appetite for 2 months; during meat inspection, thousands of various size typical tubercles, yellowish, granulomatous, and caseous lesions were distributed over all the body. Results: Microscopically, features of tuberculosis granuloma lesions were observed and revealed oval or round caseous necrosis with irregular central areas. Moreover, mineralization was enclosed by a thin to a broad layer of diverse inflammatory cells and solid collagenous connective tissue sheath. Moreover, a direct smear from the lesion stained by the Ziehl-Neelsen stain showed a slightly curved, red, and straight rod that was seen alone or in clusters, indicating the bacilli of tuberculosis. Additionally, the growing bacteria on the Löwenstein-Jensen media slant revealed flat, smooth, moist, white, not pigmented colonies suggestive of M. Bovis that revealed typical results with traditional biochemical tests, including negative reaction to nitrate reduction, niacin test, and deamination of pyrazinamide. Conclusion: For the author’s knowledge, this is the first case report of miliary bovine tuberculosis in buffalo in Iraq. The diagnosis was made according to clinical signs, gross pathology, and histopathological features supported by Ziehl-Neelsen stain and bacterial isolation. The author recommends future epidemiological molecular studies to improve the diagnosis tools of bovine tuberculosis in Iraq and investigate the causative agent M. Bovis to establish the roles for disease control that becomes much more challenging

Serum Cortisol and BMI in Chronic Diseases and Increased Early Cardiovascular Diseases

The purpose of this study was to examine the role of cortisol, and it is related to BMI in the chronic diseases which may increase early cardiovascular disease (CVD) in old Iraqi. The subjects were 116 adults, aged 51-71 years. Body Mass Index (BMI), Waist Circumferences (WC) and Waist Hip Ratio (WHR) were used as a measure of adiposity. Investigation showed highly significant difference between patients in BMI ranges, most of male were in an obese weight range (48.5%), as well in women. There were no significant correlations between serum cortisol concentration and age both gender groups. While there were highly significant correlations between cortisol level and BMI, waist, and WHR (except in female subjects), also there were highly significant correlations between cortisol level and SBP,DBP (mmHg)only in male. In both groups, total cholesterol concentration, FBS, and A1C were significantly correlated with serum cortisol. Negatively correlated has been observed between serum cortisol and HDL-C in men but not in women. In men, the results of cortisol with CV risk factors (dyslipidemia, D.M, hypertension, at least 2 risk factors and three risk factors) show significant differences (p>0.0). In summary, there is a major association between cortisol levels, obese, and chronic diseases. These conclusions promote the hypothesis that the opposing effect of adiposity on the chronic diseases might be mediated by cortisol. This association could cause early development of cardiovascular diseases even in males

Combined use of anaerobic digestion and Fischer-Tropsch reaction to convert organic wastes into biodiesel

Transportation sector consumes a high amount of energy (e.g., gasoline and diesel) and is the main responsible for a large part of the CO2 and other pollutants emissions. Replacing the energy derived from fossil fuel required in this sector with that derived from a renewable resource, such as biomass, is a solution that can relieve global warming and other environmental problems. This work focuses the attention on the overall process that includes the anaerobic digestion of organic wastes, and the conversion of the biogas produced to Biofuels by Fischer-Tropsch (FT) synthesis. The first aim of the present work is the optimization of the anaerobic digestion processes for biogas production from Municipal Solid Wastes (MSW) under mesophilic conditions, the anaerobic co-digestion of Municipal Solid Wastes (MSW) with lignocellulosic biomasses from Giant reed (GR), the effect of mineral solution "M9 10x" and 400x salts addition, and the effect of trace metals addition in individual and mixed form. The results show that the highest amount of biogas as well as the highest methane fraction were obtained adopting a suitable combination of the operating parameters (15 wt. % of TS, 10 V/V% of inoculum, co-digestion of 75% GR and 25% MSW, with the addition a mineral and salt solution and addition of 5mg/L from individual elements of Ni, Co and Zn, however higher production was with the addition a mixture of three above elements at concentration 5mg/L for each one). The second aim is the optimization of the FT synthesis reaction for the exploitation of the synthesis gas (H2 and CO) obtained by a reforming step of the methane produced by anaerobic digestion. Under the operating conditions adopted, the main product of the FT reaction were liquid hydrocarbons. The FT reaction was studied under diluted conditions with H2/CO ratio equal to 2 and extruded cylindrical pellets (d = 2 mm) of Cobalt-Alumina based catalyst. Working with diluted condition (4% H2, 2% CO, 94% He) drastically reduces the influence of the temperature, since the FT reactions are highly exothermic, allowing to hypothesize a kinetic mechanism at isotherm conditions. The catalyst was prepared by impregnation technique under vacuum condition with 15% wt. of Cobalt, and it has been characterized using a temperature-programmed reduction (TPR) technique and a N2 adsorption isotherm. The experimental investigation on FT reaction was conducted varying the GHSV, from 370 to 820 h-1, and the temperature from 220 to 250 °C, using a fixed bed reactor with 5 g of catalyst. Liquid and gaseous phases products were analyzed by gas-chromatography techniques, in the range C1, C2-C4, C5-C11, C12-C20 and C21+ according to the number of C atoms in the chains. The results indicated that changes in the temperatures and GHSV do not have a significant effect on the conversion of diluted syngas. On the other hand, the results show that the value of CO conversion obtained at steady state with lowest temperatures and GHSV is about 27%, which is higher than the values reported in the literature with the same H2/CO ratio for a not diluted condition. The optimum conditions were obtained adopting the lowest values of temperatures and GHSVs. Under these conditions, the liquid hydrocarbon yield at steady state was about 26% and the selectivities towards gasoline and diesel hydrocarbons were about 40.30% and 47.18% respectively

Estimation of Flexural Strength of Plain Concrete from Ultrasonic Pulse Velocity

The aim of this study is to propose mathematical expressions for estimation of the flexural strength of plain concrete members from ultrasonic pulse velocity (UPV) measurements. More than two hundred pieces of precast concrete kerb units were subjected to a scheduled test program. The tests were divided into two categories; non-destructive ultrasonic and bending or rupture tests. For each precast unit, direct and indirect (surface) ultrasonic pulses were subjected to the concrete media to measure their travel velocities. The results of the tests were mointered in two graphs so that two mathematical relationships can be drawn. Direct pulse velocity versus the flexural strength was given in the first relationship while the second equation describes the flexural strength as a function of indirect (surface) pulse velocity. The application of these equations may be extended to cover the assessment of flexural strength of constructed concrete kerb units or in-situ concreting kerbstone and any other precast concrete units. Finally, a relation between direct and indirect pulse velocities of the a given concrete was predicted and suggested to be employed in case when one of the velocities is not available can be measured for other ultrasonic pulse test application