Construction and Demolition Waste Management Practices in Sarawak: Priority for Regulation, Human Resources and Construction Method

Waste management is implemented by destroying and eliminating all waste from any sources of activities such as construction and demolition, minimising the waste, and reusing or recycling it. The primary purpose of managing waste is to reduce the amount of waste generated, and the reduction of waste aims to protect the environment. Improper waste management can cause damage to the ecosystem, increase air and water pollution, and destroy our health. Because of Sarawak's population increase, waste generation is becoming a big challenge. Among the major significant issue is lack of awareness, incompetence of the person in charge, administrative issues, lack of enforcement and poor technology. This study investigates the current implementation of managing construction and demolition waste in Sarawak. A questionnaire set was designed to obtain a perceptive opinion on the waste management practices in construction projects and demolition in Sarawak. A questionnaire survey was designed and distributed to 50 respondents from construction players in Sarawak. The respondents are among the construction players, including architects, contractors and consultants. The finding shows that many construction companies know the importance of managing waste as they have a procedure for managing waste in their construction operation. Moreover, concrete and aggregates list the highest-ranking waste from construction and demolition activities. This study provides mitigation measures and strategies to minimise the problems. It is anticipated that the finding of this study could assist contractors and developers in having a proper waste management system

Construction and Demolition Waste Management Practices in Sarawak: Priority for Regulation, Human Resources and Construction Method

Waste management is implemented by destroying and eliminating all waste from any sources of activities such as construction and demolition, minimising the waste, and reusing or recycling it. The primary purpose of managing waste is to reduce the amount of waste generated, and the reduction of waste aims to protect the environment. Improper waste management can cause damage to the ecosystem, increase air and water pollution, and destroy our health. Because of Sarawak's population increase, waste generation is becoming a big challenge. Among the major significant issue is lack of awareness, incompetence of the person in charge, administrative issues, lack of enforcement and poor technology. This study investigates the current implementation of managing construction and demolition waste in Sarawak. A questionnaire set was designed to obtain a perceptive opinion on the waste management practices in construction projects and demolition in Sarawak. A questionnaire survey was designed and distributed to 50 respondents from construction players in Sarawak. The respondents are among the construction players, including architects, contractors and consultants. The finding shows that many construction companies know the importance of managing waste as they have a procedure for managing waste in their construction operation. Moreover, concrete and aggregates list the highest-ranking waste from construction and demolition activities. This study provides mitigation measures and strategies to minimise the problems. It is anticipated that the finding of this study could assist contractors and developers in having a proper waste management system

Sifat-sifat mekanik dan terma nanokomposit asid polilaktik/cecair getah asli/polianilina diperkukuh berpenguat grafin pada kandungan rendah

Kajian ini dijalankan bagi mengkaji kesan penambahan bahan pengisi grafin berplat nano (GNP) ke atas sifat mekanik dan terma bagi nanokomposit polilaktik asid (PLA)/cecair getah asli (LNR)/polianilina (PANI). Nanokomposit PLA/LNR/PANI berpengisi GNP disediakan melalui kaedah adunan leburan dengan menggunakan mesin pengadun dalaman. Tahap pengisian kandungan bahan pengisi GNP dipelbagaikan daripada 0.2 sehingga 1.0 % bt. Spesimen yang telah dicirikan melalui ujian mekanik serta analisis termogravimetri (TGA), kalorimetri imbasan pembezaan (DSC) dan kekonduksian terma (TCA) menunjukkan peningkatan sifat yang positif dengan penambahan GNP pada kandungan rendah dalam matriks polimer. Keputusan sifat regangan, hentaman dan kestabilan terma menyatakan kandungan optimum dicapai pada 0.4 % bt. Berdasarkan ujian lenturan dan TCA pula, peningkatan optimum masing-masing didapati pada kandungan yang berbeza iaitu 0.6 dan 0.8 % bt. GNP

Investigation on the Effect of NiZn Ferrite on the Mechanical and Thermal Conductivity of PLA/LNR Nanocomposites

The mechanical and conductivity of magnetic polymer nanocomposite (MPNC) of nickel zinc (NiZn) ferrite nanoparticles incorporated with poly(lactic acid) (PLA) and liquid natural rubber (LNR) as compatibilizer is reported. The matrix was prepared from PLA and LNR in the ratio of 90 : 10. The MPNC of PLA/LNR/NiZn ferrite then was prepared via Thermo Haake internal mixer using melt-blending method from different filler loading from 1–5 wt% NiZn ferrite. The result of tensile tests showed that as the filler loading increases, the tensile strength also increases until an optimum value of filler loading was reached. Young’s modulus, tensile strength, and elongation at break have also increased. The study proves that NiZn ferrite is an excellent reinforcement filler in PLA/LNR matrix. The optimum thermal conductivity of PLA/LNR composites achieved with (4 wt% NiZn) due to the effective combination of NiZn-NiZn conductive networks. The scanning electron micrograph (SEM) reveal that the aspect ratio and filler orientation in the PLA/LNR matrix also strongly promoted interfacial adhesion between the filler and the matrix to control its properties

PCR-based construction and transformation of CodY gene deletion construct in streptococcus pneumoniae

Introduction: Streptococcus pneumoniae (S. pneumoniae) is a gram-positive diplococci belonging to the genus Streptococcus and it is a well-studied pathogenic bacterium. Pneumococcal diseases such as otitis media, pneumonia, sepsis and meningitis caused by pathogenic strains of S. pneumoniae still brought significant mortality and morbidity worldwide. The pathogenicity of S. pneumoniae is exerted by various virulence factors and one of it is the enzyme hyaluronate lyase. Hyaluronate lyase plays a major role in the invasive capability of S. pneumoniae. Its mechanism of action and crystallographic structure have been determinedbut its regulatory mechanism is still poorly understood. Drawing connections between the nutritional behaviour and invasive property of S. pneumoniae, CodY regulator is hypothesized as a potential hyaluronate lyase regulator. This work was aimed to construct CodY deficient mutant of S. pneumoniae to form foundational work for the study of CodY regulatory effect on hyaluronate lyase. Materials and method: A single gene-deletion method was chosen to create CodY mutant construct containing aphA-3 gene (encoding kanamycin resistance protein) replacement cassette by employing recombinant fusion PCR method. A single band DNA product at the expected size of 2,563 bp after recombinant fusion PCR was visualized on agarose gel electrophoresis. This indicated that the linear recombinant amplicon has been successfully constructed. The recombinant amplicon was transformed into S. pneumoniae cells of Malaysian local clinical isolate by employing the competence stimulating peptide (CSP-1) to enhance and induce natural competence. Results: No viable CodY mutant was evident post-transformation. The negative transformation result was postulated to be due to the essential nature of CodY regulator. Conclusion: This work can provide basis for recombinant fusion PCR method in designing and constructing single gene deletion construct. However, further work is needed to identify the regulatory agent of hyaluronate lyas

Statistical Optimization Using Response Surface Methodology for Enhanced Tensile Strength of Polyethylene/Graphene Nanocomposites

Despite having remarkable features such as low density, ease of fabrication and recyclability, linear low-density polyethylene (LLDPE) has several drawbacks like poor stiffness and low creep resistance which fortunately can be improved by incorporating with other suitable nanofillers. In this study, graphene nanoplatelets (GNPs) that are well-known for its high surface area and superior stability were selected to reinforce the polymer network of LLDPE via melt blending. During mixing processing, the rotor speed, mixing temperature and mixing time parameters are manipulated with the aids of 5-level-3-factor central composite rotatable design (CCRD) in order to determine the optimization of processing parameters in preparing LLDPE/GNPs nanocomposites. The experimental data is fitted with the statistically significant quadratic model with R2 value of 0.8601. The results showed that the tensile strength of LLDPE/GNPs nanocomposites could be extended to 24.80 MPa.  The optimum processing parameters for preparation LLDPE/GNPs nanocomposites were found to be at 101 rpm rotor speed, 139.8oC of mixing temperature and 13.2 min of mixing time, resulting in LLDPE/GNPs nanocomposites with tensile strength of 24.11 MPa. Conclusively, our study has provided a novel statistical design of experiment to obtain the optimum processing parameters in preparing LLDPE/GNPs nanocomposites

Antibiotic susceptibility study of metal-gentamicin complexes against Pseudomonas aeruginosa biofilms

Introduction: Inherent resistance of biofilm bacteria to conventional antibiotics is alarming because biofilms induce antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Pseudomonas aeruginosa is an infectious organism that causes the hallmark of chronic infections including hospital acquired infections that leads to high morbidity and mortality. One of the reasons for the occurrence of resistance is its ability to form biofilms. In this study, the resistance of P. aeruginosa biofilms against a series of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against the biofilms was conducted using broth microdilution assay. Results: The results showed that P. aeruginosa is susceptible against all the metal-gentamicin complexes, which include, Ni(II), Fe(II), Cu(II), Zn(II) and Co(II) complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusions: The results show that all metal-gentamicin complexes have higher antimicrobial activity than gentamicin (0.25 to 1 mmol) on its own. Finally, mechanisms of P. aeruginosa biofilms resistance to these metal-antibiotics are also proposed

Antibiotic susceptibility study Of metal-gentamicin complexes against Staphylococcus aureus biofilms

Introduction: Dental plaque is a structurally and functionally organized biofilm. Modern molecular biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be cultured. Inherent resistance of biofilm bacteria to conventional antibiotics is alarming. It induces antibiotic resistance to an order of three or more in magnitude greater than those displayed by planktonic bacteria. Staphylococcus aureus is the most dominant bacterial species isolated from the saliva and dental plaques. One of the reasons for its pathogenicity is its ability to form biofilms. In this study, the resistance of S. aureus biofilms against a eries of metal-antibiotics, an alternative to the conventional antibiotics, was investigated. Materials and Methods: A series of metal-antibiotic complexes derived from gentamicin was synthesized to give metal-gentamicin complexes. The metal contents of all the compounds were determined using Atomic Absorption Spectroscopy (AAS). Antibiotic susceptibility testing of the gentamicin-antibiotic complexes against several strains of S. aureus biofilms was conducted using broth microdilution assay. Results: The results showed that S. aureus is susceptible against Co(II) and Fe(II) gentamicin complexes; all were tested at 0.25 to 1 mmol concentrations. Conclusion(s): Co(II) and Fe(II)-gentamicin complexes demonstrated antimicrobial activity

Influence of Processing Conditions on Mechanical Behaviours of Thermoplastic Natural Rubber/ Polyaniline Blend / Farrah Diyana Zailan...[et al.]

The blend fabrication of thermoplastic natural rubber (TPNR) and polyaniline (PANI) was carried out to determine the optimization of processing conditions by the mechanical testing (tensile, bending and Izod impact test). The TPNR matrix, made up of linear low-density polyethylene (LLDPE), natural rubber (NR), and liquid natural rubber (LNR) as compatibilizer with the composition ratio at 40:50:10. TPNR/PANI (90 wt % / 10 wt %) blends was prepared via a melt blending method using an internal mixer with various processing parameter conditions. The influence of processing conditions including the processing temperature (°C), speed of rotation (rpm) and processing time (min) on the mechanical properties of blend were investigated. The results showed that the optimum processing conditions for preparing the TPNR/PANI blend was obtained at 130 °C, 30 rpm and 13 min. The morphological test has been done on TPNR, and TPNR/PANI blends using SEM characterization. The SEM micrographs confirmed the good dispersion of PANI within TPNR matrix