Mechanical behaviour of masonry assemblages built with mortar containing anti-freeze admixtures subject to sub-freezing curing temperatures

Cold weather masonry construction is a major concern for contractors in North America as well as other geographic locations. When exposed to cold conditions during construction and curing, the performance of masonry assemblies may be affected. Because of the vulnerability of mortar joints to considerable delay in setting time and low strength development rate in cold temperatures, the construction industry has been forced to follow extraordinary building methods. These methods focused primarily on protecting the freshly mixed and placed mortar from freezing for a suitable curing time. This can lead to loss of productivity rate and postponements in construction plans with related additional costs. This research evaluates the performance of mortars that contain nanocellulose and sodium nitrite and as a cold-weather admixture in masonry assemblages under sub-freezing curing temperatures. The effect of sodium nitrite with a dosage of 12% by mass of mixing water and nanocellulose with a dosage of 0.3% by mass of cement on Type S masonry mortars cured at -10°C and room temperatures was investigated. Flowability, air content, and setting time of fresh mixtures were determined. Moreover, for the hardened mortar state, the 28-day compressive strength of mortar cubes and the air content of mortar cylinders were determined. For the purpose of this study, two types of experiments were performed on masonry prisms constructed with four different kinds of mortars and cured under both sub-freezing and room temperatures. The first test was the compressive test to assess the design compressive strength and failure behaviour of the assemblies. A total of 72 prisms of six hollow concrete bricks stacked vertically with full bedding were built and tested in eight separate sets of nine prisms each. The second test was the flexural bond strength test using the bond wrench method described in CSA A3004-C9. For this test, 40 prisms were built, each one six units in height with five mortar joints for a total of 200 joints. These were divided into eight groups based on the kind of mortar used and the curing temperature. Test results indicated that the addition of sodium nitrite and cellulose nanocrystals affected the properties of the fresh and hardened mortar mixtures. The admixtures generally increased the flowability, reduced the air content, and sped up the hydration of cement. The mechanical property tests on masonry prisms showed that the compressive and flexural bond strengths of the prisms were affected considerably by the addition of these admixtures when cured at room temperature. At room temperature, the incorporation of nanocellulose in the mortar resulted in an increase in the compressive strength of the brick prisms by 15% compared to the control sample, while the use of sodium nitrite in the mortar resulted in an 11% increase in the compressive strength compared to the control prisms. For the flexural bond strength, the average results for prisms cured at room temperature indicate that the addition of sodium nitrite lowered the flexural bond strength by 14%, while incorporating nanocellulose separately or in combination with sodium nitrite improved the flexural bond strength by 13% and 14%, respectively. However, at -10°C, only samples with sodium nitrite reached acceptable compressive and flexural bond strengths (21.2 MPa and 0.404 MPa, respectively), as defined by the relevant Canadian standards. Generally, test results showed that sodium nitrite can be used successfully to minimize the adverse effects of freezing temperatures as low as -10°C on strength development of Type S mortar joints by lowering the freezing point of the mixing water, which opens a new approach in mitigating the problems associated with cold weather masonry construction. On the other hand, the use of nanocellulose at normal curing temperatures (22±2°C) resulted in a considerable improvement in the mechanical properties of masonry prisms. In order to improve the mechanical properties of the masonry assemblages, the incorporation of nanocellulose with sodium nitrite resulted in the highest compressive and flexural bond strengths at both normal and subfreezing curing temperatures. From the results discussed in this work, it is shown that the addition of sodium nitrite in masonry mortar mixtures can speed up masonry construction during the winter, with the need for only 4-8 hours of pre-curing at room temperature before being exposed to subfreezing temperatures, which is much relaxed compared to the 48 hours of protection currently required by the Canadian CSA A371 standard

PENATALAKSANAAN KASUS PURPURA HENOCH-SCHÖNLEIN PADA ANAK

Latar Belakang : Purpura Henoch-Schönlein (PHS) merupakan vaskulitis pembuluh darah kecil di kulit yang disebabkan oleh kelainan imunologik, disertai keterlibatan sendi, ginjal, saluran gastrointestinal, dan sistem organ lain. Tujuan: penelitian ini bertujuan untuk melaporkan penanganan yang telah dilakukan terhadap kasus PHS pada anak agar dapat dimanfaatkan sebagai rujukan bagi pengambilan keputusan pada kasus yang sama. Metode: Penelitian studi kasus ini merupakan kajian mendalam terhadap pasien anak laki-laki 11 tahun, dengan purpura palpabel eritematosa pada kedua lengan, tungkai dan pantat, di tempat adanya purpura tidak hilang dengan penekanan. Hasil: Diagnosis PHS ditegakkan berdasarkan anamnesis, pemeriksaan fisik dan histopatologik. Diagnosis ini memenuhi 4 dari 5 kriteria dari American College of Rheumatology tahun 1990, yaitu: purpura palpabel, nyeri abdomen dengan atau tanpa hematokesia, hasil biopsi berupa vaskulitis lekositoklastik, dan awitan usia 20 tahun atau kurang. Pengobatan dengan metil prednisolon 20 mg selama 7 hari memberikan perbaikan. Prognosis pada penderita ini quo ad vitam ad bonam, quo ad sanam dubia ad bonam dan quo ad kosmetikam ad bonam. Simpulan: Pengobatan dengan menggunakan metilprednisolon 20mg dapat memberikan perbaikan pada kasus PHS pada anak. Penurunan bertahap dosis metilprednisolon selama dua minggu menunjukkan penyembuhan secara klini

Rule Based System for Diagnosing Wireless Connection Problems Using SL5 Object

There is an increase in the use of in-door wireless networking solutions via Wi-Fi and this increase infiltrated and utilized Wi-Fi enable devices, as well as smart mobiles, games consoles, security systems, tablet PCs and smart TVs. Thus the demand on Wi-Fi connections increased rapidly. Rule Based System is an essential method in helping using the human expertise in many challenging fields. In this paper, a Rule Based System was designed and developed for diagnosing the wireless connection problems and attain a precise decision about the cause of the problem. SL5 Object expert system language was used in developing the rule based system. An Evaluation of the rule based system was carried out to test its accuracy and the results were promising

Constructability and Economical Comparison Between Two Proposed Permanent Shoring Systems in Qatar: A Case Study

This paper introduces the constructability and economic feasibility study of using one of the proposed two types of permanent shoring system for a highway project in Qatar. The cast-in-situ cantilever retaining wall and the contiguous piles wall were suggested and designed to be used as a permanent retaining system at a multi-level intersection. In this study, the construction complexities of using the cantilever retaining wall system are illustrated and compared to the contiguous piles wall. Besides, the impact on the Right-of-Way (ROW) of the road, excavation process, traffic circulation, and existing utilities are discussed. The paper summarizes the difference in the required construction materials and excavation quantity for the proposed shoring systems at the same retained elevation. Furthermore, the design of both systems is performed based on the local andinternational guidelines and regulations of the shoring system design in Qatar. The studyhas shown that both suggested systems are providing the same finishing quality while thecontiguous piles system is more effective in minimizing economic and site preparationchallenges. It also provides safer utilities handling and faster construction sequencingwithout cost increases

Basel III, And Banking Risk; Do Basel III Factors Could Predict the Risk of Middle-Eastern Countries?

The research is financed by the Nation Natural Science Foundation of China under number 71173060. Abstract The global financial crisis in 2008 shows that the successive agreements Basel I, and II failed to stop the global financial collapse. Therefore, this research tries to answer the study question that; can Basel III enhancement give the banking sectors stability? Our data includes 324 listed from the largest banks across Middle East. Results from PLS-SEM analyses demonstrate bank risk is positive relationship related to charter value, information systems and Internal/External control systems. We find negative relationship among bank risk and market discipline. Following our finding, the result shows there is no relationship between bank risk and bank capital and the results suggest that Charter Value is the most important predictor of bank risk. Keywords: Basel III, Bank Risk, Bank capital, charter value, information system, control system, market discipline, Middle East

Upaya Pencegahan dan Penularan Scabies di Pondok Pesantren Ibrohimiyyah Demak melalui Edukasi Personal Hyegiene pada Santri

Ibrohimiyyah Islamic Boarding School (“Ponpes”) is located in Brumbung RT 05 RW 04 Mranggen Demak. The density of occupancy in each room at the Ponpes causes low personal hygiene and environmental sanitation at the place. Our community service activity (Pengabdian masyrakat/PkM) was aimed to solve the problem of (1)The lack of understanding of the students (“stantri”) about the importance of personal hygiene in preventing many diseases, especially the transmission of scabies, (2) The lack of knowledge of Ponpes administrators and santri about scabies and how to prevent transmission, (3) The number of students who currently suffer from scabies and have not been handled properly who can resulting in the transmission of this disease in the cottage environment so that it affects the rest time and productivity of students. Our PkM provided health education through counseling about scabies disease, its causes, ways to prevent transmission and how to treat wounds caused by scabies to santri and Ponpes administrators. Examination of the severity of scabies was done to determine the scabies. To prevent the spreading of the disease to others, the santri with scabies was also treated by topical scabicide, namely Permethrin cream 5% or ointment 2-4, or oral Ivermectin. Education, examination and treatment of scabies in santri was useful for increasing santri' knowledge so that they are able to understand personal hygiene in preventing many diseases, especially the transmission of scabies. Santri are able to understand about scabies and how to prevent its transmission.

Three-dimensional morphometric analysis and development of new classification system of impacted canines in orthodontic patients using cone beam computed tomography

Canine teeth are aesthetically most dominant teeth which can present a smile as either holy or evil. They define the mouth’s corner, are involved in the aesthetic smile, maintain occlusal stability, and design the shape of the dental arch. As the position of the impacted canines is amidst vital anatomical structures like the nasal cavity and sinuses in the maxilla and mental nerve in the mandible, a thorough radiographic evaluation to determine the position of the impacted canines is of utmost importance prior to any treatment planning. By using a CBCT image, a clinician can clearly identify its location. The present study aimed to determine the prevalence of impacted canines in orthodontic patients and conduct morphometric analysis on the effect of impacted canines on the dental arch form and dimension and develop a new classification system. CBCT images of patients aged 15 to 50 years who attended HUSM, Malaysia, for orthodontic treatment were analysed pertaining to their arch and categorised under the proposed 3D classification system based on their location and direction during the state of impaction. The results suggested that the prevalence of impacted canines in orthodontic patients was 17.5 %, with a female preponderance. Impacted canines occurred most frequently in Class I malocclusion subjects and least in Class III malocclusion. A significant relationship between the impacted canines and adjacent anatomical structures was found in most measured variables. The impacted canines appeared to be interrelated with arch dimension measurements. The findings showed significant changes in the study group compared to the control group. Interpremolar, intermolar widths and arch length were significantly deficient and narrower, with higher palatal vault seen in impacted canine patients as compared to the control group. Based on the new classification system, the most common type of impacted maxillary canines was V1AP, followed by V2BP, V2AP, and V2CP. V3BL, N2AP and N3AP were the least common. For impacted mandibular canines, M1AP was predominant, followed by M2AP, M1CP, and M2AL. Whilst M1AL and M1BP were the least prevalent. The present 3D investigation provides a new clinical reference value for the prevalence of impacted canines based on ethnicity, gender, and different types of malocclusion in addition to the relationship with surrounding anatomical structures and dental arch dimensions. Furthermore, this study established a new system for classifying impacted maxillary and mandibular canines to facilitate interdisciplinary communication for better treatment planning

Azo dyes decolourisation by ABTS-oxidases (Laccases) from a fungus from tropical tree

Lignin is an important constitute of the wood and thus the organism like fungi and insects growing on wood produce some extracellular lignolytic enzymes. In fungi these enzymes include different oxidases and peroxidases. Lignin peroxidases, manganese peroxidases, versatile peroxidases and laccases have been characterised from fungi and their roles in wood decay has been established. Here we report ABTS-oxidases from an unidentified fungus isolated from tree bark sample from Kuantan, Malaysia. After the liquid media cultivation, the crude extracellular protein content was extracted and analysed by polyacrylamide gel electrophoresis. SDS-PAGE, native PAGE and zymography were carried out. Azo dyes, brilliant green, trypan blue, direct red 80 and eriochrome black T were used for decolourisation activity of the isolated fungus on solid medium. The results suggest that the extracellular proteins contain laccase enzyme activity. Out of the four azo dyes that were used for dye decolourisation assay, at least three were decolourised to different extents by the fungus