Diagonal Cracking Capacity and Ultimate Shear Strength of Slender RC Beams without Web Reinforcement

This study presents a method that combines both dimensional analysis and statistical regression analysis for predicting the shear capacity of slender reinforced concrete (RC) beams without web reinforcement taking the size effect into consideration. This method incorporates the modified Buckingham-PI theorem (Butterfield, 1999, Geotechnique 49(3), 357-366) to formulate two mathematical models for predicting the shear capacity at the formation of diagonal tension cracks and at the ultimate shear strength. The results of the two models are compared with several sets of existing experimental results. This study shows that the variations in the experimental results of shear capacity of slender RC beams ( a / d  2.5 ) defined at the formation of diagonal tension cracks of beams can be explained by the variations of the concrete tensile strength and the variations in the experimental results of ultimate shear strength of slender RC beams ( a / d  2.5 ) can be explained by the variations of the concrete splitting strength

Consolidation Characteristics Based on a Direct Analytical Solution of the Terzaghi Theory

A new method is proposed for evaluating both the coefficient of consolidation cv and end of primary settlement δ p based on a direct analytical solution of the Terzaghi theory. In this study, the cv value is shown to be inversely proportional to the δ p value. The proposed method utilizes both the early and later stages of consolidation (i.e., the entire range of consolidation) for the evaluation of both parameters. The proposed method requires four consolidation data points; two points for back-calculating the initial compression and two points for extrapolating the δ p value. Results of oedometer tests on three clayey soils show that the cv and δ p values of the proposed method are quite comparable to those of the Casagrande method but generally lower than those of the Taylor method

Undrained Shear Strength and Swelling Characteristics of Cement Treated Soil

This study investigates the influence of cement addition on the behavior of an expansive soil from Jordan. A wide range of cement content varying from 0 to 25% by dry weight of soil was used. This study shows that the liquid limit of the treated soil decreases drastically for cement content of up to 6%, then sharply increases for cement content in the range of 6 to 10% after which the liquid limit becomes practically constant. This study shows also that the swell potential of the treated soil decreases drastically for cement content of up to 4%, then sharply increases for cement content in the range of 4 to 6% after which the swell potential may decrease or may become constant depending on the initial water content. The undrained shear strength was generally observed to increase with the increase of cement content from 0 to 20%; however, the maximum rate of this increase was observed to be in the range of cement content from 6 to 10%. These results are interpreted in terms of cation exchange, flocculation and pozzolanic reactions that are associated with cement addition to soil

Consolidation Analysis by the Slope and Settlement Rate - Settlement Methods

This paper presents results of consolidation analysis using two recently developed methods for obtaining the coefficient of consolidation ( cv ) and the end-of-primary (EOP) settlement  p . The first method (the slope method, Al-Zoubi, 2008b) computes cv and EOP  p entirely from the early stages of consolidation at 6 . 52  U % using the observed linear section of t  - t plot. The second method (the settlement rate - settlement method: Al-Zoubi, 2010) computes cv and p  entirely from the later stages of consolidation at 6 . 52  U % using the observed linear section of settlement rate - settlement curve (i.e., dt d t /  - t  curve). Extensive experimental results of oedometer tests on four clayey soils show that the two methods give quite similar cv and  p values that are also in good agreement with those of the Casagrande method. These results also show that the Taylor method cv values are generally lower than those of the slope, settlement rate – settlement and Casagrande methods

Identifying the Crack Nature Using b-Value Acoustic Emission Signal Analysis

Concrete is an important constituent of structures. The strength performance of the concrete decrease due to several factors. Concrete suffers from deterioration at a later stage. Early and constant identification of concrete deterioration is necessary. Nowadays, non-destructive testing (NDT) is widely used especially on continuous real-time monitoring system with minimum labor involvement. It could also be used to discriminate the different types of damage occurring in reinforced concrete (RC) beam and real structure. In this research was monitored by using Acoustic Emission testing and it have several analysis such as RA-value, b-value, intensity signal analysis and historical index. To determine the acoustic emission signals for concrete structures and cracking identification this research using b-value analysis. b-value signals analysis contain useful information about damage mechanisms. A high b-value arises due to a large number of small AE hits, it representing new crack formation and slow crack growth, whereas a low b-value indicates faster or unstable crack growth accompanied by relatively high amplitude AE in large number. Reinforced concrete beams measuring of size 150 mm 250 mm 1500 mm were used during the acoustic emission test. A four-point load test was carried out on specimens until cracking occurred. The signals generated from the equipment were used for the analysis process, and the values are compared to define and summarise type of cracking and cracking processes

Cloves protect the heart, liver and lens of diabetic rats

Clove oil was previously reported to modulate physiological responses in streptozotocin-induced diabetic rats. This study attempts to evaluate the in vivo organ and tissue protective effects of dietary cloves (Eugenia aromaticum) in chronic hyperglycaemia. The cloves (equivalent to 100 mg total eugenol + eugenyl acetate per kg body weight/day) were administered orally to streptozotocin-induced diabetic male Sprague-Dawley rats. Fasting blood glucose levels, as well as organ tissue physical and biochemical markers, were monitored. Dietary supplementation with cloves reduced tissue injuries, especially in the lens and cardiac muscles, and to a lesser extent in the liver but not the kidneys. Additionally, the cloves treatment significantly reduced blood sugar increases and lipid peroxidation in streptozotocin-induced diabetic rats by restoring the antioxidant enzyme levels. Cloves inhibited hyperglycaemia-induced oxidative tissue damage and cataract formation in the eye lens. This study demonstrates the in vivo antioxidative organ protective effects of clove in diabetics

Identification of Critical Success Factors (CSFs) for Public Private Partnership (PPP) Construction Projects in Syria

The collaboration between the public and the private sectors is an important issue that has attracted the attention of most governments around the world. Public Private Partnership (PPP) is one important approach among many that meets this goal. Syria, in the present time, needs this type of contract to reduce the huge pressure on the treasury by attracting the required funds for developing, extending and operating many vital infrastructure projects. In fact, the best results obtained from PPP contracts depend on determining the Critical Success Factors (CSFs), which are influenced by the local strategies and related to the nature of each of these factors and its importance, without neglecting the nature of the project under consideration. This research aims at identifying the critical success factors that influence PPP projects in Syria based on previous similar studies supported by a structured questionnaire survey. It also attempts to uncover the current PPP practice and highlight the main obstacles that hinder its implementation in the Syrian construction industry. The identified CSFs are ranked according to their importance, for public and private sectors independently and collectively. This research ultimately aims at developing a new practical framework to help decision makers both in public and private sectors in selecting the optimum PPP contract for the construction industry in Syria taking the most important CSFs into account

The Effects Of A Self-Evaluation Multimedia Courseware On Learning Restricted Arabic Consonants Among Non-Arabic Speakers : A Case Study

Kajian ini memfokuskan kepada kesan koswer multimedia penilaian kendiri dalam pembelajaran sebutan huruf-huruf konsonan Arab terhad (HKAT) di kalangan penutur bukan Bahasa Arab (PBBA). Para pengkaji sebelum ini mendapati bahawa PBBA menghadapi masalah dan gagal menyebut HKAT dengan betul apabila mereka mempelajari bahasa Arab. Masalah ini berpunca daripada beberapa sebab termasuklah kerana ketiadaan HKAT tersebut dalam bahasa Inggeris, dan keperluan menggunakan sistem artikulasi pelajar bagi menghasilkan sebutan baru yang tidak terdapat dalam bahasa ibunda mereka. Kajian ini menggunapakai pendekatan kajian kes yang melibatkan empat orang pelajar dewasa PBBA dari sebuah kolej awam di Emiriah Arab Bersatu, dan mereka dipilih secara rawak daripada kawasan geografi berbeza. Keempat-empat pelajar tersebut menggunakan pembelajaran kendiri dengan berpendekatan penilaian kendiri, di mana satu koswer multimedia untuk mengajar mereka untuk menyebut HKAT dengan betul telah dibangunkan. The current study focuses on the effects of self-evaluation multimedia courseware in learning the pronunciation of the Restricted Arabic Consonants (RACs) by Non Arabic Speakers (NASs). Studies showed that NASs face difficulties and cannot pronounce the RACs properly when they learn Arabic language. The problem is due to different reasons including the RACs are not available in the English language, and the need to learn how to use new parts of the learner’s articulation system to produce the new sound which are not available in the learner’s mother tongue. This research uses a case study approach with four adult NAS learners from a government college in the United Arab Emirates and they were selected randomly from different regions of the world. The four learners used a self-learning with a self-evaluation approach and a specially developed multimedia courseware to teach themselves how to pronounce the RACs correctly or in acceptable manner

The immune response to Mycobacterium avium induced in avian and human macrophage-like cell lines and in chickens

Avian tuberculosis remains a significant economic problem for the poultry industry in many countries. An improved understanding of the interaction between host and mycobacteria is important in designing more efficient vaccine strategies. This study investigated the immune responses to M. avium (Ma.) strains isolated from different sources, Ma strains 1-2 isolated from chickens, Ma.3-5 from cattle and Ma.6-8 from humans, using human cells in vitro and avian cells in vitro and in vivo. The responses were characterised by expression levels of pro-inflammatory cytokines tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β, IL-6 and chemokines CXCLi1 (K60) and CXCLi2 (IL-8) and nitric oxide production. A differential immune response was observed between the strains in terms of induction of cytokine and chemokine production in both human THP-1 and avian HD11 cells. With the exception of the avian strains 1 and 2, all strains induced increases in pro-inflammatory cytokines in THP1 cells. Two of the 3 bovine strains also had this effect in HD11 cells but the other strains had little effect. Use of specific inhibitors indicated that in THP-1 cells the extracellular regulating kinase (ERK) and c-Jun N-terminal kinase (JNK) pathways were important in inducing pro-inflammatory cytokines whereas the p38 pathway did not appear to be involved particularly in regulating TNF-α and IL-1β production. The results also indicate an interaction between the mitogen activated protein kinases (MAPK) pathways studied in regulation of cytokine production in HD11 cells. Although layer chickens were resistant to extensive M. avium multiplication in the tissues, significant expression of pro-inflammatory cytokines was observed in the liver of infected birds towards the end of the period of observation of 21 days as granulomata had started to appear, characterised by lymphocyte accumulation. In conclusion, the findings of this study provide further understanding of the host-mycobacteria interaction and that different strains of M. avium might behave differentially regardless of their source of isolation

Measles outbreak investigation in Ginnir district of Bale zone, Oromia region, Southeast Ethiopia, May 2019

Introduction: measles is a vaccine-preventable viral infection of humans, primarily affecting children <5 years. During early 2019, outbreak of measles occurred in Ginnir district of Bale zone, Southeast Ethiopia. We investigated to describe the outbreak and identify risk factors. Methods: we conducted a descriptive and 1:2 unmatched case-control study in Ginnir district from March 18 to April 29, 2019. Fifty-six cases and 112 controls were recruited. For descriptive study, we identified 1043 cases recorded on the line-list and for case-control study, cases were identified using national standard case-definition. Mothers of case-patients and controls were interviewed using structured questionnaire. We estimated vaccine efficacy (VE) from case-control study. We conducted bivariate and multivariable logistic regression. Results: in four-months period, a total of 1,043 suspected measles cases epidemiologically linked to five laboratory confirmed cases reported. Of which, 555 (53.2%) were males and 714 (68.5%) were <5 years. The median age of cases was 36 months (IQR=12-60 months). The overall attack rate (AR) was 63/10,000 population with case fatality ratio of 0.5% (5 deaths/1043). Infant <9 months were the most affected age groups (AR=31/1000). Majority (79%) of measles cases were not vaccinated against measles. Last-year (2017/18) administrative measle vaccine coverage of the district was 76.7%. Being unvaccinated against measles (AOR=5.4, 95%CI=2.2-13.4), travel history (AOR=4.02, 95%CI=1.2-13.6), contact with measles case-patient (AOR=5.6, 95%CI=2.12-14.4) and mothers knowledge of measles transmission (AOR=0.36, 95%CI=0.15-0.87) were associated with measles infection. VE in children aged 9-59 months was 90% (95%CI=69-97%). Conclusion: this confirmed measles outbreak was caused by failure to vaccinate, as indicated by the high VE, low administrative coverage, and 79% unvaccinated cases. Strengthening routine and supplementary immunization are required