Penyingkiran boron daripada larutan akuas menggunakan penjerap komposit berasaskan karbon-mineral (Boron removal from aqueous solutions using composite adsorbent based on carbon-mineral)

Penyingkiran boron dalam larutan akuas secara penjerapan telah dikaji dengan menggunakan penjerap komposit yang menggabungkan zeolit, batu kapur, karbon teraktif dan buangan arang sekam padi. Parameter optimum seperti pH, masa sentuhan optimum dan dos bahan penjerap dikaji. Kajian isoterma penjerapan dan kinetik penjerapan turut dijalankan. Hasil penyelidikan menunjukkan penyingkiran boron paling optimum berlaku pada pH5 dan masa sentuhan optimum ialah pada minit ke 120. Dos optimum bagi penyingkiran boron dalam larutan akuas ialah pada dos 280 g/L dan penyingkiran yang dapat dilakukan ialah sebanyak 50.49%. Dalam kajian isoterma, model isoterma Langmuir dan Freundlich telah diaplikasikan dan hasil kajian membuktikan bahawa kajian isoterma penjerapan adalah mematuhi model isoterma Langmuir (R2 = 0.8792). Nilai kapasiti penjerapan maksimum (qm) yang diperoleh daripada model isoterma Langmuir adalah 1.8985 mg/g. Kajian kinetik penjerapan dijalankan untuk mengetahui mekanisme proses penjerapan dan hasil kajian menunjukkan kadar kinetik bagi penjerapan boron ini adalah mematuhi model kinetik tertib kedua. Pekali korelasi yang diperoleh untuk model kinetik tertib kedua ini adalah 0.9929. Ini mencadangkan bahawa kinetik penjerapan boron adalah dipengaruhi oleh proses kimia

Waste management: a qualitative study exploring the perception of flood waste management among the community of Pasir Mas

The purpose of this paper is to examine the 2014 post-flood waste management in affected area. For this purpose, Pasir Mas in Kelantan was chosen as the sample area and interviews were conducted with the residents. The interviews aim to gather information about post-flood waste produced, sources of the waste, actions taken by the residents and related authorities bodies to clear the waste, impact of the waste on their living surroundings and health, and assistance needed to manage the waste. A total of 39 respondents consisted of 20 men and 19 women were selected at random for focus group discussion. These respondents represent persons of age 25 years old and above, local and whose living quarters have been affected by the flood. The large volume of mud left by the flood has been identified by the participants as the main source of the post-flood waste. In addition, good cooperation between government agencies and the residents is important to speed up the waste clearing works. However, residents are in much needed support, awareness and education about the impact of long due waste clearing on their health and living environment

Isoprene hotspots at the Western Coast of Antarctic Peninsula during MASEC′16

Isoprene (C5H8) plays an important role in the formation of surface ozone (O3) and the secondary organic aerosol (SOA) which contributed to the climate change. This study aims to determine hourly distribution of tropospheric isoprene over the Western Coast of Antarctic Peninsula (WCAP) during the Malaysian Antarctic Scientific Expedition Cruise 2016 (MASEC′16). In-situ measurements of isoprene were taken using a custom-built gas chromatography with photoionization detector, known as iDirac. Biological parameters such as chlorophyll a (chl-a) and particulate organic carbon (POC) were compared to the in-situ isoprene measurements. Significant positive correlation was observed between isoprene and POC concentrations (r2 = 0.67, p < 0.001), but not between isoprene and chl-a. The hotspots of isoprene over maritime Antarctic were then were investigated using NAME dispersion model reanalysis. Measurements showed that isoprene mixing ratio were the highest over region of King George Island, Deception Island and Booth Island with values of ∼5.0, ∼0.9 and ∼5.2 ppb, respectively. Backward trajectory analysis showed that air masses may have lifted the isoprene emitted by marine algae. We believe our findings provide valuable data set of isoprene estimation over the under sampled WCAP

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Effect of compaction energy on engineering characteristic of compacted soil

Soil compaction is a significant stage in construction. When field compaction is performed improperly, soil excessive settlement could occur and result in unnecessary maintenance costs or structure failure. The objective for this research is to study the effect of compaction energy to compaction characteristic of granular soil. Granular soil is widely used as a replacement soil when dealing with soft soil such as peat and very soft clay. Furthermore, granular soil is commonly used in pavement of runaway which requires strong base to sustain heavy load from vehicles. Compactive effort is one factor that affects the quality of compaction. Standard and Modified Proctor had been used to show the effect of compactive effort to the river sand and laterite soil samples. The study proved that the maximum dry density of soils increases when the compactive effort increases which also contributed to higher shear strength

Airborne particles in the city center of Kuala Lumpur: Origin, potential driving factors, and deposition flux in human respiratory airways

Equatorial warming conditions in urban areas can influence the particle number concentrations (PNCs), but studies assessing such factors are limited. The aim of this study was to evaluate the level of size-resolved PNCs, their potential deposition rate in the human respiratory system, and probable local and transboundary inputs of PNCs in Kuala Lumpur. Particle size distributions of a 0.34 to 9.02 μm optical-equivalent size range were monitored at a frequency of 60 s between December 2016 and January 2017 using an optical-based compact scanning mobility particle sizer (SMPS). Diurnal and correlation analysis showed that traffic emissions and meteorological confounding factors were potential driving factors for changes in the PNCs (Dp ≤1 μm) at the modeling site. Trajectory modeling showed that a PNC ˂100/cm3 was influenced mainly by Indo-China region air masses. On the other hand, a PNC >100/cm3 was influenced by air masses originating from the Indian Ocean and Indochina regions. Receptor models extracted five potential sources of PNCs: industrial emissions, transportation, aged traffic emissions, miscellaneous sources, and a source of secondary origin coupled with meteorological factors. A respiratory deposition model for male and female receptors predicted that the deposition flux of PM1 (particle mass ≤1 μm) into the alveolar (AL) region was higher (0.30 and 0.25 μg/h, respectively) than the upper airway (UA) (0.29 and 0.24 μg/h, respectively) and tracheobronchial (TB) regions (0.02 μg/h for each). However, the PM2.5 deposition flux was higher in the UA (2.02 and 1.68 μg/h, respectively) than in the TB (0.18 and 0.15 μg/h, respectively) and the AL regions (1.09 and 0.91 μg/h, respectively); a similar pattern was also observed for PM10