ANALISIS HUBUNGAN PARAMETER CUACA TERHADAP KONSENTRASI POLUTAN (PM2.5 DAN CO) DI WILAYAH JAKARTA SELAMA PERIODE WORK FROM HOME (WFH) MARET 2020

Intisari Selama ini Jakarta dikenal dengan kota berpolusi dengan indeks pencemaran udara yang cukup tinggi. Salah satu penyebab pencemaran udara adalah polutan partikulat (PM2.5) dan gas CO yang berasal dari pembakaran tidak sempurna. Pada masa pandemi Covid-19, pemerintah menerapkan kebijakan Pemberlakuan Pembatasan Kegiatan Masyarakat (PPKM) untuk menekan jumlah penularan virus Covid-19. Jakarta Pusat sebagai salah satu kota yang melaksanakan kebijakan PPKM mewajibkan perkantoran yang ada untuk menerapkan Work From Home (WFH). Jumlah konsentrasi polusi udara PM2.5 pada periode WFH Maret 2020 tidak jauh berbeda dibandingkan lima tahun sebelumnya. Sedangkan konsentrasi CO pada periode yang sama mengalami penurunan dibandingkan lima tahun sebelumnya. Hasil analisis hubungan antara pengaruh parameter cuaca dengan konsentrasi polutan menunjukkan pengaruh parameter cuaca kurang signifikan terhadap konsentrasi PM2.5 dan gas CO. Nilai R-Square adj antara beberapa parameter cuaca terhadap konsentrasi PM2.5 dan konsentrasi CO cukup kecil. Hal ini menunjukkan bahwa pengurangan nilai konsentrasi PM2.5 dan gas CO bukan dipengaruhi oleh parameter cuaca. Faktor lain yang diduga memengaruhi konsentrasi PM2.5 dan gas CO adalah kegiatan manusia seperti WFH sehingga terjadi pengurangan aktivitas masyarakat untuk pergi ke kantor. Abstract Jakarta is known as a polluted city with a high air pollution index. One of the air pollution causes is particulate pollutants (PM2.5) and CO from incomplete combustion. During the Covid-19 pandemic, the government implemented a policy of Community Activity Restrictions, known as PPKM, to reduce the number of transmissions of the Covid-19. As one of the cities implementing the PPKM policy, Central Jakarta requires offices to implement Work From Home (WFH). The total PM2.5 air pollution concentration in the March 2020 WFH period was not much different from the previous five years. However, the CO concentration in the same period decreased compared to the last five years. Relationship analysis between the influence of weather parameters and pollutant concentrations shows that weather parameters are less significant on PM2.5 and CO concentration. The R-Square adj between several weather parameters on the concentration of PM2.5 and the concentration of CO is small. It means that weather parameters do not influence the reduction in the concentration of PM2.5 and CO. It is assumed that the PM2.5 and CO concentrations decreased due to fewer human activities in the office and public areas.

Neutron diffraction and ab initio studies on the fully compensated ferrimagnetic characteristics of Mn2V1-xCoxGa Heusler alloys

Neutron diffraction and ab initio studies were carried out on Mn2V1-xCoxGa (x = 0, 0.25, 0.5, 0.75, 1) Heusler alloys which exhibits high TC fully compensated ferrimagnetic characteristics for x = 0.5. A combined analysis of neutron diffraction and ab initio calculations revealed the crystal structure and magnetic configuration which could not be determined from the X-ray diffraction and magnetic measurements. As reported earlier, Rietveld refinement of neutron diffraction data confirmed L21 structure for Mn2VGa and Xa structure for Mn2CoGa. The alloys with x = 0.25 and 0.5 possess L21 structure with Mn(C)-Co disorder. As the Co concentration reaches 0.75, a structural transition has been observed from disordered L21 to disordered X a. Detailed ab initio studies also confirmed this structural transition. The reason for the magnetic moment compensation in Mn2(V1-xCox)Ga was identified to be different from that of the earlier reported fully compensated ferrimagnet (MnCo)VGa. With the help of neutron diffraction and ab initio studies, it is identified that the disordered L21 structure with antiparallel coupling between the ferromagnetically aligned magnetic moments of (Mn(A)-Mn(C)) and (V-Co) atom pairs enables the compensation in Mn2V1-xCoxGa.

Research of the internal environment of the military camp buildings

One of the key tasks of this research work is to assess the carbon dioxide (CO₂) pollution in the resting areas of military camps under the current deployment conditions and to assess its impact on soldiers. In the process, the environmental impacts that affect the CO₂ concentration were researched in different rooms in different ways. In addition to the rest areas of a military camp, enumerating the major camp facilities that affect the “welfare” feeling of soldiers on foreign mission, we arrived at the kitchen complex and the work environment of the kitchen staff. One of the key parts of the camp kitchen complex is the food storage, where the raw materials needed for the supply are stored. Storage is very important in a crisis situation, when you have to be prepared to stay away from the homeland, to prevent any supply or procurement problems. A particularly important task in providing food raw materials is the so-called "Fresh" storage. The aim of the paper is to examine the changes in the CO₂ concentration of the camp storage room, which is of key importance in food supply, in the vegetable (fruit) storage places. By modeling at a measurement site set up in the laboratory of the host institution, we measure the CO₂ composition of the indoor air in the warehouse by placing various vegetables and fruits. The change of CO₂ concentration is examined separately for certain types of vegetables and fruits stored in closed storage rooms, taking into account the degree of effective storage capacity and determine the required fresh air value to ensure proper storage conditions. Finally, a mathematical model to simulate changes in storage conditions will be created, which offer help to plan of the military camp.

Investigation of CO Deactivation of Passive NOx Adsorption on La Promoted Pd/BEA

Passive NOx adsorption (PNA) is a method, in which NOx can be stored at low temperatures and released at higher temperatures where the urea decomposition is functional during selective catalytic reduction (i.e., above 180–200 °C). We have studied the promotion of Pd/BEA with La as a PNA in the presence of high CO concentration. Both the reference and promoted samples exhibited a significant loss of NOx adsorption/desorption capacity after multiple cycles using 4000 ppm CO. However, already after 5 cycles, 99% of the NOx released between 200 and 400 °C was lost for Pd/BEA, compared to only 64% for Pd-La/BEA, which thereafter was stable. XPS and O2-TPD clearly showed that the Pd species were influenced by La. The PNA deactivation in the presence of CO could be related to Pd reduction followed by migration and the formation of more PdOx clusters, as observed by O2-TPD analysis. Interestingly, significantly more PdOx clusters formed on Pd/BEA after 10 cycles compared to Pd-La/BEA.

Simulation of Emergency Evacuation from Construction Site of Prefabricated Buildings

To ensure the safe construction of prefabricated buildings and improve the efficiency of the safe evacuation of construction personnel after a fire caused by improper operation during construction, this study used the PyroSim software to numerically simulate a fire situation based on the size and volume of a prefabricated building construction site. The variation rules of smoke visibility, CO concentration, and ambient temperature in the construction site of prefabricated buildings were analyzed and the available safe evacuation time was determined. Moreover, the Pathfinder software was used for simulation in combination with the physical attributes of personnel, evacuation speed, and personnel proportions. The time required for safe evacuation was determined and the factors influencing the evacuation time, such as the quantity and location of stacked prefabricated components, machinery, and appliances, and the number of on-site construction personnel, were analyzed. The results reveal that the original layout of the prefabricated building construction site cannot facilitate the safe evacuation of all construction personnel. The bottleneck area for the evacuation of construction personnel is the indoor corridor and evacuation stairway. The quantity and location of stacked items at the construction site greatly influence the evacuation time. When the number of construction personnel on each floor reaches a certain value, restrictions should be imposed. The results obtained by this study can provide the theoretical basis for the rational planning of evacuation routes and construction site management.

Can Exhaled Carbon Monoxide Be Used as a Marker of Exposure? A Cross-Sectional Study in Young Adults

Carbon monoxide (CO) poisoning is a major public health issue worldwide. People are exposed to CO in their daily lives, with one of the common sources of CO being cigarette smoking. Inhalation of CO leads to elevated carboxyhaemoglobin (COHb) levels in the blood and also in exhaled CO concentration. Several factors have been shown to affect COHb concentration and COHb half-life. However, factors affecting exhaled CO concentration and exhaled CO half-life are not well understood. The present study aimed to investigate the potential factors related to baseline exhaled CO concentration and exhaled CO half-life among smokers. A cross-sectional study was conducted between 26 January and 30 June 2019, and young adults were recruited into the study. A total of 74 participants (mean age: 27.1 years, 71.6% males and 28.4% females) attended the study. They were invited to complete a questionnaire, including demographic, physiological, and behavioural factors. Then, exhaled CO measurements were taken. These measurements were taken before and after smoking a single cigarette for smokers and only once for non-smokers. The average baseline exhaled CO concentration was 6.9 ± 4.9 ppm for smokers and 1.9 ± 0.5 ppm for non-smokers. The mean of exhaled CO half-life was around 273.3 min (4.6 h) for smokers. No difference was seen in exhaled CO half-life between light smokers and heavy smokers in the smoking group. Gender and cigarettes smoked weekly affected baseline exhaled CO in smokers. Even though height seemed to positively associate with exhaled CO half-life, the relationship disappeared when adjusting by gender and weight. Therefore, exhaled CO could be used as a marker of CO exposure, but we cannot ignore the factors mentioned in the study. For future study, considering factors related to smoking habits and smoking style are recommended as these may affect total inhaled CO.

Heat Treatment Effect in the Corrosion Resistance of the Al-Co-Mn Alloys Immersed in 3 M KOH

Al-based alloys named M1, M2, M3, M4, and M5 doped with different atomic percentage (at%) of cobalt and manganese as cast and submitted at two heat treatments (600°C and 1100°C) were analyzed by using electrochemical techniques to evaluate their corrosion resistance immersed in 3 M KOH. With the heat treatments applied to the alloys, the sample M2 (65% Al, 20% Co, and 15% Mn) observed the highest corrosion resistance with R p values of 3.0 × 10 2 , 6.2 × 10 2 , and 1.61 × 10 3 Ω · c m 2 as cast, 600°C, and 1100°C, respectively. The latter was in agreement with the I corr calculated from the polarization curves where the values decrease based on the heat treatment applied as follows: 1.60 × 10 3 > 6.16 × 10 2 > 3.07 × 10 2 mA / c m 2 for 1100, 600, and as cast, respectively. Co concentration above 20% increases the corrosion current ( I corr ) and decreases the polarization resistance of the remain samples. The chemical analysis done with EDS and X-ray diffraction made confirmed the presence of compounds such as CoAl, Co2Al5, Co2Al9, MnAl4, and MnAl6.

Prediction of Carbon Monoxide (CO) Atmospheric Pollution Concentrations with Machine Learning and Time Series Analysis in Langkawi, Malaysia

Carbon monoxide (CO) is a non-irritant toxic and odourless gas produced from the incomplete combustion of fossil fuels. Long-term exposures to lower levels of carbon monoxide have wide implications for human health. Thus, an early warning system for CO atmospheric concentration with an accurate and reliable forecasting method is crucial. Studies for predicting CO atmospheric concentration are still limited in Malaysia especially using data science approaches. This study aims to develop and predict future CO concentration for the next few hours by using the statistical time series approach and machine learning approach. The data used for the project is the air quality data of the monitoring station in Langkawi, Malaysia. The data mining tool used for this project is RapidMiner Studio. Based on the results, it showed that Time Series analysis with deep learning gave a reasonably good CO concentration prediction for the next 3 hours with a relative error of approximate 10%. The model developed in this project can be used by authorities as public health’s protection measure to provide an early alarm for alerting the Malaysian populations on the air pollution issue.