Early detection of corrosion activity in reinforced concrete slab by AE technique

Chloride induced corrosion of steel reinforcement in concrete is the main cause of damage to concrete structures in marine, or structures exposed to de-icing salt environments. The need for early detection of corrosion in reinforced concrete structures is widely acknowledged in corrosion health monitoring for strategic civil engineering projects. This paper summarizes results from a laboratory experiment, using Acoustic Emission (AE) technique, regarding early detection of corrosion in reinforced concrete slabs that are exposed to chloride. The Results showed that while AE was able to determine the initiation of corrosion in reinforced concrete slab, Half-cell potential (HCP) was not able to detect it at the early stage of corrosion

إنتاج مادة 17 ألفا هيدروكسي البروجستيرون على مستوى المخمر المعملي بواسطة فطرة كاننجهاميلا إيكينولاتا

The mircrobiological transformation of progesterone by a local isolate of Cunninghamella echiiiulata using a laboratory fermentor was studied. Progresterone (10-50 g/1) wetted by Tween 80 was added to 48-hour old culture and the transformation was left to proceed for 72 hours. Thereafter, the different transformation products were resolved chromatog-raphically. The identity of each product was established through the determination of m.p., mixed m.p., optical rotation and ultraviolet as well as infrared absorption spectra. A comparison of the R{ values of each product with that of the corresponding reference using different solvent systems as well as their colour expressed with two spray reagents, was used as a further proof for the identity of the isolated products. With all concentrations of progesterone tested, maximum yield of 17ot -hydroxyprogesterone was obtained after 48 hours of fermentation Progesterone concentrations of 10 and 20 g/1 were almost quantitatively converted to the different transformation products after 72 hours of fermentation. Using a concentration of 20 g/1 and incubation period of 48 hours, the transformation product mixture consisted of unchanged progesterone (6%), 17 o< -hydroxyprogesterone (54%),llotrhydroxyprogesterone (29%) and llo<;,17<^-dihydroxy-progesterone (2.5%).تم استخدام مخمر صناعي سعة 2 لتر لاختيار مقدرة الفطرة على تكوين هذه المادة في ظروف تشبه تلك المطبقة في الصناعة . وبدراسة تركيزات متعددة فن مادة البروجستيرون تتراوح ما بين 10جرام /لتر إلى 50جرام /لتر ، وجد أن أنسب التركيزات المختبرة هو تركيز 20 جرام من البروجستيرون لكل لترمن الوسط الغذائي ، حيث تم تحويل كل البووجستيرون المضاف إلى المشتقات المختلفة خلال 72 ساعة من بدء الاضافة . ووجد أن أعلى معدل لتكوين مادة 17 ألفا - هيدروكسي البروجستيرون كان بعد 48 ساعة من بدأ إضافة البروجستيرون . عند فصل المواد الناتجة من تحول البروجستيرون بواسطة الفطرة المستخدمة وذلك بواسطة أعمدة الفصل باستخدام مادة الالومينا وجد أن البروجستيرون يتحول إلى : 17 ألفا - هيدروكسي البروجستيرون ( 54 %) 11 ألفا - هيدروكسي البروجستيرون (29%) 11 ألفا ، 17 ألفا - ثنائي هيدروكسي البروجستيرون (2.5%

Studying the Dynamical Properties of 20 Nearby Galaxy Clusters

Using SDSS-DR7, we construct a sample of 42382 galaxies with redshifts in the region of 20 galaxy clusters. Using two successive iterative methods, the adaptive kernel method and the spherical infall model, we obtained 3396 galaxies as members belonging to the studied sample. The 2D projected map for the distribution of the clusters members is introduced using the 2D adaptive kernel method to get the clusters centers. The cumulative surface number density profile for each cluster is fitted well with the generalized King model. The core radii of the clusters' sample are found to vary from 0.18 Mpc \mbox{h}^{-1} (A1459) to 0.47 Mpc \mbox{h}^{-1} (A2670) with mean value of 0.295 Mpc \mbox{h}^{-1}. The infall velocity profile is determined using two different models, Yahil approximation and Praton model. Yahil approximation is matched with the distribution of galaxies only in the outskirts (infall regions) of many clusters of the sample, while it is not matched with the distribution within the inner core of the clusters. Both Yahil approximation and Praton model are matched together in the infall region for about 9 clusters in the sample but they are completely unmatched for the clusters characterized by high central density. For these cluster, Yahil approximation is not matched with the distribution of galaxies, while Praton model can describe well the infall pattern of such clusters.Comment: 16 pages, 8 figure

Experimental investigation of feedforward control schemes of a flexible robot manipulator system

This paper presents experimental investigations into the applications of feedforward control schemes for vibration control of a flexible manipulator system. Feedforward control schemes based on input shaping and filtering techniques are to be examined. A constrained planar single-link flexible manipulator is considered in this experimental work. An unshaped bang-bang torque input is used to determine the characteristic parameters of the system for design and evaluation of the input shaping control techniques. The input shapers and filtering techniques are designed based on the properties of the system. Simulation results of the response of the manipulator to the shaped and filtered inputs are presented in time and frequency domains. Performances of the shapers are examined in terms of level of vibration reduction and time response specifications. The effects of derivative order of the input shaper on the performance of the system are investigated. Finally, a comparative assessment of the control strategies is presented and discusse

Physico-mechanical properties of polymer concrete containing micro-filler of palm oil fuel ash

Objective of this study is to present a research conducted on ground (fine) and unground (coarse) POFA in polymer concrete (PC) followed by determination on the physico-mechanical properties of PC. Physical properties of micro-fillers and mechanical properties of produced PCs were characterized. Calcium carbonate and silica sand were also used as micro-fillers for comparison purpose. The samples were subjected to compression and flexural. Morphology images of the particles were captured under morphology test to support the findings. Results showed that fine POFA micro-filler has a highly promising potential in becoming PC filler compared to coarse micro-filler. Additionally, its produced PC had comparable strength to PC with calcium carbonate. From the strength development and sustainability stand point, fine POFA has demonstrated its capability to produce quality and sustainable P

Review on sheet metal forming process of aluminium alloys

The application of aluminum alloys in automotive and aerospace industries has been growing significantly in the last 20 years. Due to their high specific strength, aluminum became a strong replacement for steel particularly at automotive manufacturing. However, to deform a complex panel part from aluminum is quite challenging specifically at cold forming condition in which the formability is quite low. Many attempts have been processed to improve the formability problem of the aluminum alloy such warm forming, hot forming, superplastic forming and Hot forming and cold die quench (HFQ) processes. This paper presents a critical survey for different forming methods and identifying the advantages and drawbacks for each method. This review will help researcher to be familiar about the history, development and state of art of metal forming processes of aluminum sheet alloys

Palm oil fuel ash as the future supplementary cementitious material in concrete

The use of Palm Oil Fuel Ash (POFA) as a pozzolanic material for partial cement replacement in concrete reduces the cost of concrete as well as cuts down the number of landfill area required for disposing the ash. This paper presents a comprehensive review of the engineering properties and durability aspects of blended cement concrete incorporating POFA as a partial replacement of ordinary Portland cement (OPC). An Ordinary Portland Cement concrete mix termed P0 and two POFA concrete mixes with different fineness termed (POFA 45 and POFA 10) at 20% replacement level by weight of cement were considered in the study. Acid solution was found to be the most destructive under the applied exposure conditions on P0. The loss of mass and the resistance to chloride penetration were found to be depended on the degree of fineness of POFA to which the specimens were exposed. As for the values obtained from compressive strength test, P0 specimens were found to be the lowest compared with specimen consisting POFA. On the other hand, POFA 10 exhibited better resistance against acid than POFA 45. Conclusively, integration of POFA as partial cement replacement, especially very fine POFA increases the resistance of high strength POFA concrete towards both chloride attack and acid attack

Fabrication of bricks from paper sludge and palm oil fuel ash

Increasing amount of disposed paper sludge and palm oil fuel ash (POFA) from industries has recently attracted concern for an alternative environmentally sustainable application. This paper presents results of laboratory work carried out on these by-products in order to evaluate application performance. Brick specimens made with various proportions of cement, paper sludge and POFA were fabricated and studied under laboratory conditions. Curing periods of 7, 28 and 84 days were applied followed by compressive strength test. Leaching and water absorption capacities were also assessed as prime steps towards monitoring durability in service. It was found that paper sludge-POFA brick made with 60% cement, 20% sludge and 20% POFA satisfies the strength requirements of BS 6073 Part 2: 2008 and that the amount of copper as well as lead resulting from leaching are within the acceptable limits of ‘Malaysia Environmental Waste Disposal Act

Assessment of Fences as Noise Barriers: A Case Study in New Cairo, Egypt

Noise levels in Egypt exceed acceptable thresholds due to high population and lack of mandatory sound regulations. According to noise measurements done by “The National Network for Noise Level Measurement in Greater Cairo” most of the areas examined ( main squares, industrial areas, main roads, residential areas, commercial and administrative areas in Cairo governorate)&nbsp; had shown that noise levels exceeded the standard permissible levels that are identified by the Environmental Law 4/1994 and its executive regulations. Noise levels reached up to 75-85 decibels (dB), which is considered unacceptable as noise levels should not exceed 65 dB during daytime and 55 dB during night due to law number 4/1994. On the other hand, fences are considered a common feature within the Egyptian urban context and are mainly constructed for safety and privacy reasons. This research assesses the effectiveness of existing fences as noise barriers and specifies factors that reduce noise levels. Site measurements and photographs were taken for the fence of a residential compound in new Cairo, where noises arising from surrounding places cause annoyance. MEP services were the main sources of disturbing continuous noise along with social activities and traffic noises. Measurements were performed using TM-102 digital sound level meter. Readings were recorded at various time intervals in front and behind of the fence and noise reduction levels were calculated. Measurements revealed that the fence acts as a good noise barrier and that combined configuration of the fence resulted in the attenuation of noise to acceptable levels

Characterization of Hepatitis B Viral Drug Resistance in Indian Subcontinent Patients with Chronic Liver Disease.

Globally, an estimated two billion people are infected with hepatitis B virus (HBV) and around 350 million live with chronic infection. Approximately 75% of these patients reside in the Asia-Pacific region, India harbouring the second largest pool of about 50 million chronic HBV carriers. About 15% to 40% of HBV infected subjects develop complications leading to cirrhosis, decompensated cirrhosis and hepatocellular carcinoma (HCC) contributing to over 1 million deaths per year. Thus HBV associated liver diseases is considered to be of public health importance, emphasizing the need for the prevention and control of disease progression. Hepatitis B virus is a circular, partially double-stranded DNA virus of the family Hepadnaviridae. The virus is classified into 8 major genotypes and several subgenotypes with an intergenotypic diversity of 8% and intra-genotypic diversity of 4% respectively. These genotypes have known to show a geographical pattern in their distribution and have been used to trace the migration of populations from geographically distant regions. The HBV strains are also distinguished into nine major subtypes based on their antigenic determinants in the major hydrophilic region. Hepatitis B virus genotypes and subtypes have been reported to influence disease progression and treatment response. Therefore, determination of HBV genotypes and subtypes is important for disease monitoring and clinical outcome. The study aimed to characterize the antiviral resistance mutations in Indian subcontinent subjects with chronic hepatitis B. It was also aimed to identify the association between HBV genotypes, subgenotypes, subtypes and treatment outcome in these subjects. The antiviral efficacies of three widely used drugs in this country i.e., lamivudine, adefovir and entecavir were studied. In view of the limited potency and high resistance rates to lamivudine, our study emphasises the use of more potent drugs in the treatment of chronic hepatitis B to ensure an optimum virological response and prevent the progression of disease. Though the frequencies of adefovir resistance mutations are low, there is paucity in the proportion of subjects who showed virological response. Therefore, adefovir in the management of HBV should be used judiciously. Among the three drugs studied, entecavir seems to be a suitable drug of choice in the management of HBV. However, due to cost constraints long-term use of entecavir is implausible in resource limited countries like India. Our study has identified some baseline and on-treatment predictive factors of response and non-response. Our study has also revealed valuable information that would widen the scope of testing antiviral resistance mutations for appropriate tailoring of therapy. The absence of resistance mutations in most of the non-responders for all three drugs in our study subjects is contradictory to the expectation. We also show that HBV genotypes and subtypes do not influence treatment outcome to all three antiviral drugs studied. Further, based on the findings of this study we hypothesize that high viral genetic diversity, elevated baseline serum aminotransferases and spontaneous anti-HBe seroconversion (suggesting a high immune response) coupled with antiviral action play an effective role in clearing the viral infection. We also propose that future studies be directed towards extending the combination therapy approach to HBV, as currently practiced in the management of HIV infection