LAMINAR MIXING IN SMX STATIC MIXERS

This paper experimentally examines the performance of a commercial static mixer (SMX). Experiments were carried out to obtain the pressure drop across different numbers of mixing elements (4, 8, 12 and 16). The quality of mixing was visually assessed using flow visualization techniques. Experiments were performed for Reynolds number between 50 and 3000 (based on the unobstructed pipe diameter). The presence of the mixing elements in the flow stream promotes a non-laminar, turbulent-like flow which considerably enhances the mixing. Addition of more mixing elements triggered mixing in the flow at lower Reynolds numbers but this was achieved at the expense of higher pressure drop. This work represents the first stage of an on going work to develop correlations to assess the mixing quality and pressure loss in the SMX static mixers

THE INFLUENCE OF WAVE PATTERNS AND FREQUENCY ON THERMO-ACOUSTIC COOLING EFFECT

With the increasing environmental challenges, the search for an environmentally benign cooling technology that has simple and robust architecture continues. Thermo-acoustic refrigeration seems to be a promising candidate to fulfil these requirements. In this study, a simple thermo-acoustic refrigeration system was fabricated and tested. The thermo-acoustic refrigerator consists of acoustic driver (loudspeaker), resonator, stack, vacuum system and testing system. The effect of wave patterns and frequency on thermo-acoustic cooling effect was studied. It was found that a square wave pattern would yield superior cooling effects compared to other wave patterns tested

Liquid air as an energy storage:A review

With the increasing demand for energy due to rapid industrialisation and the environmental concerns due to the usage of fossil fuels as the main energy source, there is a shift towards renewable energy. However, the intermittent nature of renewable energy requires energy produced during off-peak hours to be stored. This paper explores the use of liquefied air as an energy storage, the plausibility and the integration of liquefied air into existing framework, the role of liquefied air as an energy storage in addressing the Grand Challenges for Engineering as well as its employability in Malaysia

INVESTIGATION OF ACCD3 GENE OF MYCOBACTERIUM TUBERCULOSIS IRAQI ISOLATES

Objective: Mycobacterium tuberculosis, one of the deadliest human pathogens, causes several million new infections and about 2 million fatalities annually. The cell wall of M. tuberculosis is endowed with a highly impermeable, complex array of diverse lipids such as mycolic acids, which bestow the bacterium with not only virulence but also resistance to host immunity and antibiotics.Methods: Mycobacterial lipid metabolism has thus emerged as an attractive target for the design and development of novel antimycobacterial therapeutics. The first committed step in the biosynthesis of mycolic acid is the carboxylation of acetyl-CoA to malonyl-CoA which is catalyzed by acetyl-coenzyme A carboxylase carboxyl transferase beta subunit (accD3), a primer pairs were designed computationally and used for the amplification of accD3 gene using conventional polymerase chain reaction (PCR) and sequencing the PCR product and analyze the results.Results: Two sequences of the detection gene (LprM gene) and eight sequences of accD3 gene under study were deposited at NCBI – GenBank database with accession numbers (LC009881, LC009880.1, LC006979, LC008196, LC009412, LC009414, LC034168, LC038020, LC041163, and LC041368) and primer pairs deposited at Probe database/NCBI with accession number Pr032816836.Conclusion: AccD3 gene is a good drug target in MDR M. tuberculosis strains

EXPERIMENTAL INVESTIGATION OF OPEN LOOP MULTI-STAGE IMPEDANCE PUMPING SYSTEM

Impedance pump is a simple valveless pumping mechanism, where an elastic tube is joined to a more rigid one; a periodic asymmetrical pinching on the elastic tube will produce a unidirectional flow. This pumping concept offers a low energy, low noise alternative at both micro and macro scales. This paper describes an experimental investigation of the performance of a two-stage, open loop impedance pump. The results show that, when compared to a single stage open loop impedance pump, the two-stage impedance pump can achieve a significant pressure head and flow rate increment. A pressure head increment of 240 Pa is obtained in the single stage system compared to 480 Pa for the two-stage system. The corresponding flow rates were 5 mL/s and 8 mL/s respectively. This is an indication that impedance pumping system can be scaled up to achieve a variety of pumping assignments

Environmental Study of Some Water Characteristics at Um-Al-Naaj Marsh, South of Iraq.

Um-Al-Naaj region in Al-Hawiezah Marsh, Southern Iraq was chosen to study the environmental variations of some water characteristics during 2008, seasonally. The results showed clear seasonal changes in values of some environmental variables (temperature, depth, light penetration, turbidity, total suspended solids, pH, dissolved oxygen, reactive phosphate, reactive nitrite, and reactive nitrate), while there were no clear seasonal changes in electrical conductivity and salinity values. In addition, high nutrients concentrations and light penetration were noted. Statistical analysis showed significant positive relationship between air and water temperature; electrical conductivity and salinity. Water turbidity was significantly affected by total suspended solids. On the other hand, some of the studied variables had significant negative effects (relative relationships) to each other, when water pH and dissolved oxygen were affected by temperature; total suspended solids and turbidity affected also light penetration

Cytogenetic screening of chromosomal abnormalities and genetic analysis of FSH receptor Ala307Thr and Ser680Asn genes in amenorrheic patients

Objective Amenorrhea is a rare reproductive medical condition defined by the absence of menstruation during puberty or later life. This study aims to establish the frequency and pattern of chromosomal abnormalities (CA) in both primary amenorrhea (PA) and secondary amenorrhea (SA), and further to detect the genetic changes in exon 10 at nucleotide positions 919 and 2039 of the genotypes Thr307Ala, and Asn680Ser, respectively. Design, settings and patients This cross-sectional study was conducted on a sample of seventy amenorrhoeic women according to the Helsinki declaration rules of medical ethics, as divided into 40 (57.14%) with PA and 30 (42.86%) with SA, and 30 healthy women with normal menstruation as the control. The chromosomal karyotyping was performed according to the ISCN, 2020. PCR products were submitted to RFLP and Sanger sequencing for women with normal karyotype and high FSH serum levels. Results The classical Turner Syndrome was the most common CA in PA, followed by isochromosome X [46, Xi(X)(q10)], mosaicism of Turner and isochromosome X [45, X /46, Xi(X)(q10)], sex reversal (46, XY) and (46, XX,-3,+der3,-19,del 19 p). Abnormal SA cases were characterized by mosaicism Turner syndrome (45,X/46,XX) and (46,XX,-3,+der3,X,+derX). The homozygous genotypes AA and GG of Ala307Thr (rs6165) in the FSHR gene are most common in PA, while the homozygous genotype AA is more common in SA. GG and AG genotypes of Ser680Asn (rs6166) are more frequent in Iraqi patients with PA and SA compared to the healthy control women. Both PCR-RFLP and Sanger sequencing indicated a marked matching between genotypes. Conclusions The study emphasizes the need for cytogenetic analysis to determine the genetic basis of PA and SA. Further, genotyping for women with normal karyotype and high FSH serum concentrations via PCR-RFLP should be considered for the precise diagnosis and development of appropriate management of and counselling for these patients