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Fulltext Shear Capacity of Singly and Doubly Webbed Corrugated Web Girder

Hanizah Abdul Hamid, Azmi Ibrahim, Norhisham Ibrahim

Scientific Research Journal, 2006;3(1):53-68.
MyJurnal

A conventional plate girder involves the use of transverse intermediate
stiffeners, especially in a slender web to avoid catastrophic failure associated
with shear buckling of the web. In this study, a profiled web was used to
replace the transversely stiffened web. The process involves introducing coldformed
ribs into a flat steel sheet to form alternative stiffeners. This study
therefore seeks to establish comparative performance of conventionally
stiffened plate girders and profiled web girders of a specially formed rib
arrangement with single and also double webs. Nine numbers of specimens
were tested to failure under a three-point-bending system. Failure of all the
profiled web girders, with either a single or double webs, is characterized by
a shorter yield plateau and a steeper descending branch, a failure mode that
is commonly referred to as ‘brittle’. The results of the tests on girders with
profiled steel sheets, PSS(s) have shown that profiling is extremely effective in
increasing the shear buckling load because it moves the sheet material out of
the plane of the web, thereby increasing the rigidity 1.08 to 2.0 times higher
than the equivalent conventional flat web plate girders. The experimental
results also showed that post-buckling capacities are reduced by 30 % to
50 % of their ultimate shear capacities.
Fulltext Pull-out performance of t-stub end plate connected to concrete filled thin-walled steel tube (CFTST) using Lindapter Hollo-bolts

Nazrul Azmi Ahmad Zamri, Petrus, Clotilda, Azmi Ibrahim, Hanizah Ab Hamid

Scientific Research Journal, 2018;15(1):59-74.
MyJurnal

The application of concrete filled steel tubes(CFSTs) as composite members has widely been used around the world and is becoming popular day by day for structural application especially in earthquake regions. This paper indicates that an experimental study was conducted to comprehend the behaviour of T-stub end plates connected to concrete filled thin-walled steel tube (CFTST) with different types of bolts and are subjected to pullout load. The bolts used are normal type bolt M20 grade 8.8 and Lindapter Hollo-bolt HB16 and HB20. A series of 10 mm thick T-stub end plates were fastened to 2 mm CFTST of 200 mm x 200 mm in cross-section. All of the specimens were subjected to monotonic pull-out load until failure. Based on testresults, the Lidapter Hollo-boltsshowed better performance compare to normal bolts. The highest ultimate limit load for T-stub end plate fasten with Lindapter Hollo-bolt is four times higher than with normal bolt although all end plates show similar behaviour and failure mode patterns. It can be concluded that T-stub end plate with Lindapter Hollo-bolt shows a better performance in the service limit and ultimate limit states according to the regulations in the design codes.
Fulltext Bending and bonding properties of sandwiched polymer concrete composites

Hamidah Mohd Saman, Azmi Ibrahim, Yakub Md. Taib, Mohd. Faizal Md. Ja’afa

Scientific Research Journal, 2006;3(2):13-29.
MyJurnal

It is foreseen that the properties of Polymer Concrete (PC) can be further
enhanced if the PC is bonded to or sandwiched between Glass Fibre Reinforced
Plastic (GFRP) laminates, later termed as PC-GFRP system. In the present
investigation, the performance of PC-GFRP was assessed in terms of its bending
strength and bonding strength between PC and GFRP. Panels of PC size 500
mm × 500 mm × 20 mm were prepared. The panels then were cut into specimens
of appropriate geometry and dimensions required for the tests. Four (4) different
resin contents and different percentages of aggregate of different particle size
distributions were employed in preparing the PC-GFRP specimens. A batch of
PC specimens was layered with a Glass Fibre Reinforced Plastic (GFRP)
laminate on one side (SSL) and the other batch PC specimens were sandwiched
with two GFRP laminates (DSL). The PC-GFRP specimens were tested their
bending strength under three-point load test and bonding strength between
PC as a core material and glued GFRP laminate(s). The results showed that an
increase in the resin content increases the bending strength of the PC regardless
of the aggregate grading. The results also revealed that the PC specimens with
well-graded aggregate recorded the highest bending strength, with coarser
grading resulted in further increase. The bending strength of the PC-GFRP
Fulltext Blood pressure control and cardiovascular risk profiles among post-stroke survivors: a cross-sectional study.

Hui Jie Wong, Sakinah Harith, Pei Lin Lua, Khairul Azmi Ibrahim

IIUM Medical Journal Malaysia, 2020;19(2):29-39.
MyJurnal

Control of modifiable risk factors is important in recurrent stroke prevention strategies. This study aimed to determine the control of blood pressure and other cardiovascular risk profiles among post-stroke patients. Factors associated with uncontrolled blood pressure were also determined. MATERIAL ANDMETHODS:A cross-sectional study was conducted in the outpatient clinics of three hospitals located in the East Coast region of Peninsular Malaysia from May to August 2019. Information on socio-demographic characteristics, clinical profiles, and lifestyle practices were acquired. Univariate and multivariate logistic regression analyses were carried out. Crude odds ratio and adjusted odds ratio (aOR) were reported. RESULTS:From a total of 398 stroke patients, majority of the respondents were elderly with first-ever stroke, ischaemic type, and duration of stroke less than 24 months. Uncontrolled blood pressure (52%), overweight and obesity (65%), abdominal obesity (54%), and low physical activity level (65%) were common among the patients. Patients with hypertension (aOR= 3.11, 95% CI: 1.38, 6.99), diabetes mellitus (aOR 1.57, 95% CI: 1.03, 2.38), not taking prescribed medication every day (aOR 2.28, 95% CI: 1.29, 4.01), overweight (aOR 1.75, 95% CI:1.02, 2.99), obesity (aOR 1.99, 95% CI: 1.12, 3.53), and low physical activity level (aOR 2.10, 95% CI: 1.35, 3.27) were at a higher risk of having uncontrolled blood pressure. CONCLUSION:Uncontrolled blood pressure and other major cardiovascular risk factors were highly prevalent among post-stroke patients. Increased efforts must be made to optimise the risk profiles management of these high-risk patients to prevent recurrent vascular events in the future.
Fulltext Microstructure and mechanical properties of hybrid super ElasticNiTi alloy with steel rebar for reinforced concrete beam

Nubailah Abd. Hamid, Muhammad Akmal Ahmad Shazalli, Muhammad Hussain Ismail, Azmi Ibrahim

Pertanika Journal of Science & Technology, 2017;25(107):89-100.
MyJurnal

NiTi is well known for its shape memory effect and super elasticity (SE), and is widely used in medical, dentistry and aerospace applications. For shape memory, NiTi has the ability to undergo deformation at certain temperature then recover to its original shape while SE occurs at narrow temperature range just above its transformation temperature. It shows that this material remembers its original shape and is elastic under stress. The application of nitinol as partial replacement in reinforced concrete beam for seismic resistant structures is popular due to it re-centring capability and distinctive properties. Using Shape Memory Alloy (SMA) in structures has its downsides. Hence, hybrid reinforced concrete beam with SMA was introduced to improve the structure’s ductility and energy dissipation. Hence, this research is aimed at distinguishing microstructure and mechanical properties of SMA and steel rebar. Not much is known about how SMA behaves when subjected to compression. Therefore, X-Ray Diffraction (XRD) was used to analyse if any secondary phase exists and Differential Scanning Calorimetry (DSC) test was used to analyse the phase transformation. The results showed hybrid NiTi-steel rebar can address some deficiencies of NiTi and in terms of costs. On the other hand, combining them will result in super elastic recovery, displacement ductility and strength capacity for seismic resistant design.
Fulltext Postnatal ex vivo rat model for longitudinal bone growth investigations

Abubakar AA, Ibrahim SM, Ali AK, Handool KO, Khan MS, Noordin Mustapha M, et al.

Animal Model Exp Med, 2019 Mar;2(1):34-43.
PMID: 31016285 DOI: 10.1002/ame2.12051

BACKGROUND: Chondrocytes in the growth plate (GP) undergo increases in volume during different cascades of cell differentiation during longitudinal bone growth. The volume increase is reported to be the most significant variable in understanding the mechanism of long bone growth.
METHODS: Forty-five postnatal Sprague-Dawley rat pups, 7-15 days old were divided into nine age groups (P7-P15). Five pups were allocated to each group. The rats were sacrificed and tibia and metatarsal bones were harvested. Bone lengths were measured after 0, 24, 48, and 72 hours of ex vivo incubation. Histology of bones was carried out, and GP lengths and chondrocyte densities were determined.
RESULTS: There were significant differences in bone length among the age groups after 0 and 72 hours of incubation. Histological sectioning was possible in metatarsal bone from all age groups, and in tibia from 7- to 13-day-old rats. No significant differences in tibia and metatarsal GP lengths were seen among different age groups at 0 and 72 hours of incubation. Significant differences in chondrocyte densities along the epiphyseal GP of the bones between 0 and 72 hours of incubation were observed in most of the age groups.
CONCLUSION: Ex vivo growth of tibia and metatarsal bones of rats aged 7-15 days old is possible, with percentage growth rates of 23.87 ± 0.80% and 40.38 ± 0.95% measured in tibia and metatarsal bone, respectively. Histological sectioning of bones was carried out without the need for decalcification in P7-P13 tibia and P7-P15 metatarsal bone. Increases in chondrocyte density along the GP influence overall bone elongation.
Fulltext Characterization of alumina using small angle neutron scattering (sans)

Megat Harun Al Rashid Megat Ahmad, Abdul Aziz Mohamed, Azmi Ibrahim, Che Seman Mahmood, Putra, Edy Giri Rachman, Muhammad Rawi Muhammad Zin, et al.

Journal of Nuclear and Related Technologies, 2007;2005(1):19-23.
MyJurnal

Alumina powder was synthesized from an aluminum precursor and studied using small angle neutron scattering (SANS) technique and complemented with transmission electron microscope (TEM). XRD measurement confirmed that the alumina produced was of high purity and highly crystalline D-phase. SANS examination indicates the formation of mass fractals microstructures with fractal dimension of about 2.8 on the alumina powder.