Environmental Science

One of the most critical problems throughout the world is air pollution, causing the death of millions of individuals annually, and it is reported that 90% of the global population breathes polluted air. Among the components of air pollution, the most harmful ones are the heavy metals, which can remain non-degraded in nature for a long time, bio-accumulate in living organisms, and be toxic or carcinogenic at low concentrations. Hence, monitoring and reducing heavy metal pollution in the air are high-priority research topics. Heavy metals can accumulate within various organs of plants grown in an environment with an increased level of heavy metal pollution. The metal analyses on these organs can provide insight into the heavy metal pollution in the air. In the present study, the concentrations of aluminum (Al), one of the most important heavy metals, were determined in the different organs of five plant species grown in regions with different traffic densities. Remarkable changes wer...

Climate and rain parameters are important factors that affect the availability of water resources on the earth's surface. The phenomenon of climate change that occurs today has an impact on the depth and distribution of rain and climatological parameters. The existence of rain and climate on Lombok Island changes very significantly every year. These changes affect various sectors, especially the irrigation sector. Thus, various adjustments must be made, such as adjusting the time of planting, cropping patterns and the types of plants being cultivated. In this case, knowledge about the characteristics of rain and climate that occurs on the island of Lombok is very important to know the pattern and magnitude of the incident as well as the time of the incident. This study was conducted to determine the condition of each climate variable in the Lombok island region by calculating the monthly average for 25 years. The smoothing uses the Theissen polygon method by utilizing 19 scatter...

Papua New Guinea (PNG) is blessed with numerous energy resources, including oil, gas, wind, solar, tidal and biomass. Renewable energy resources have taken centre stage as PNG along with other countries seek to push for 32% of its national power demand to be met by renewable energy sources by the year 2030. In addition, PNG has an ambitious programme to provide electricity to 70% of its scattered population by the year 2030. In this paper we discuss PNG’s energy sector and we present an initial Geospatial Information System (GIS) based study to consider the development of renewable energy power generation at the new Umi Township in the Markham valley of Morobe Province. The Markham valley has sunshine for about 8 hours per day and an average insolation of about 500 W/m 2 each day. At a height of about 50 m from the ground, the velocity averages to 4m/s. The paper will present the preliminary evaluation carried out using the GIS based data. It will also draw some general conclusions ...

grains are lost during post-harvest processing and storage due to insect infestation. Increased production would hardly have any significance unless protected from post harvest loss. A recent estimate by the Ministry of Food and Civil supplies put the total preventable post-harvest losses of food grains due to insect infestation at about 20 million tons per year, which was nearly 10 per cent of the total production that could have fed up to 117 million people for a year. Insect pest activity in agricultural produce may start at any stage from harvest to consumption. Insect infestation causes qualitative and quantitative losses of food commodities and changes the chemical composition affecting the nutritive value of the produce. Drying is the most common and fundamental method for post-harvest preservation of food commodities because it allows for the quick conservation of the food qualities of the plant material in an uncomplicated manner. Since agriculture is the main preoccupation...

Controlling the amount and level of sugar industry waste must be done carefully, ranging from sugar cane harvesting in the field to the processing of cane into sugar mill. The aim of this research is constructing model and getting strategy and policy of sugar industry waste management based on clean production using dynamic system.  This research was conducted at Sei Semayang plantation and sugar mill, PTPN II, North Sumatera in January until  July 2013.Dynamic model system of waste management based on clean production was analyzed using Powersim program, license by sofware house Powersimtm, USA. The research shows Dynamic model of sugar industry waste management can be done by combining environmental subsystem model and socio-economical subsystem. The scenario and policy of sugar industry waste management based on clean production results in waste minimilization, production process efficiency and increase of agricultural contribution, that it increases the surrounding community’s i...

In this paper, the use of HVAC systems and non-HVAC control measures to reduce virus-laden bioaerosol exposure in a highly occupied indoor space is investigated. A simulation tool was used to model the fate and transport of bioaerosols in an indoor space in the hotel industry (bar or pub) with three types of HVAC system (central air handling system (CAHS), dedicated outdoor air system (DOAS), and wall unit system (WUS)). Non-HVAC control measures such as portable air cleaners (PAC) and local exhaust fans were considered. Occupant exposure was evaluated for 1 μm bioaerosols, which transport SARS-CoV-2, for 3 h/day of continuous source and exposure. The combined effects of ventilation (400 l/s of outdoor air), recirculated air filtration (90% efficacy), and a PAC with a capacity up to 900 m3/h mitigated the (normalized) integrated exposure of the occupant by 0.66 to 0.51 (CAHS) and 0.43 to 0.36 (DOAS). In the case of WUS, the normalized integrated exposure was reduced by up to 0.2 whe...

This paper presents an experimentally validated, dynamic model of a hybrid liquid desiccant system. For this purpose, we developed new components for the air-solution contactors, which are of the non-adiabatic falling-film type with horizontal tubes (made of improved polypropylene) and the solution tanks. We also provide new experimental correlations for both the tube-solution heat transfer coefficient and the mass transfer coefficient on the airside as a function of the air velocity. To validate the model, the results obtained from the dynamic simulations were compared with those obtained by monitoring a demonstration unit installed in a sports center in Taipei (Taiwan). Once validated, the model was used to perform a sensitivity analysis at different operational conditions, such as the inlet water temperatures in the air-solution contactors and the LiCl mass fraction at which the system operates. The results of the sensitivity analysis were used to optimize the seasonal performanc...

The mayflies are insects widely known as indicators of aquatic quality in freshwater systems, they are abundant and diverse in tropical streams. In this study, it was determined the influence of physical, chemical and bacteriological characteristics on the Ephemeroptera assembly in a period of low precipitation in the Ocoa river of Meta department. There were 5,332 nymphs belonging to 4 families, 10 genera and 3 species. Three new genera records and one species are presented for Meta: Cloeodes, Zelusia, Lumahyphes and Americabaetis alphus. The genera Camelobaetidius and Varipes were found associated with conditions of contamination by organic matter and water mineralization. Likewise, Americabaetis, Thraulodes, Lumahyphes and Tricorythodes were associated with contamination conditions, especially with nitrites and nitrates. Nanomis, Cloeodes and Zelusia showed greater sensitivity to the contamination condition and were related to high percentages of dissolved oxygen in the water and...

Aims: Selection of a suitable solvent is important and utilized in the extraction of desirable chemical components in medicinal plants. Study Design: Chemical analysis of various extracts of Leea guineensis leaves using standard analytical procedures. Place and Duration of Study: Forestry Research Institute of Nigeria, between March 2019 and August 2019. Methodology: Leaves of Leea guineensis were extracted with six solvents categorized into polar (Acetone, Methanol and Aqueous) and non-polar (Ethyl acetate, Hexane and Chloroform) types using cold maceration method, the qualitative and quantitative phytochemical assay was done on the respective extracts using the standard methods. Results: Phytochemical screening of the non-polar solvent extract revealed the presence of flavonoids, alkaloids and saponins for all the solvents, while tannin was present only in ethyl acetate extract. For the polar solvent extracts, all the secondary metabolites determined were present except terpenoids...

Liquid bulk transport is one of the most important modes of fluid package transport, whether by sea or land. Flexitank has recently attracted the attention of shipment companies as an alternative method of fluid transportation due to the benefits of cost effectiveness, large shipping capacity, environmental friendliness, and quick loading/unloading time. However, the industry reports some cases regarding the leakage of the flexitank during transportation. While the hydrodynamic behaviour of the flexitank during transportation may influence the tank surface leakage issue. Thus, this study aims to determine the suitable filling volume capacity on flexitank by using Computational Fluid Dynamics (CFD). Hydrodynamics performance such as wall shear stress, volume fraction, dynamic pressure, and slosh force will be analyzed on different filling volume capacities and driving cycles. The filling volume capacity analyzed in this study are 5%, 10%, 15% more, or less than the reference capacity...

Groundwater flow and transport predictions are a major component of remedial action evaluations for contaminated groundwater at the Savannah River Site. Because all groundwater modeling results are subject to uncertainty from various causes; quantification of the level of uncertainty in the modeling predictions is beneficial to project decision makers. Complex site-specific models present formidable challenges for implementing an uncertainty analysis.

Urbanization affects land cover and a region’s prevailing land surface temperature (LST). As a result, understanding the effects of urbanization on LST and land cover change is critical for effectively planning, managing, and monitoring urban development and undesired LST change. This paper, therefore, examines the relationship between the change in four land cover categories and LST during 1987–2004 and 2004–2021. Our approach uses the Total Operating Characteristic (TOC) to study the relationship between LST change and the losses and gains in four land cover categories: infrastructure, vegetation, water, and bare land in Abeokuta South, Nigeria. We derived the land cover and LST dataset from satellite imagery at time points 1987, 2004, and 2021. Our results show that most of the vegetation in the study area transitions to bare land and infrastructure during both time intervals, while most of the bare areas transition to infrastructure and vegetation. Furthermore, the TOC analysis ...

 Food poisoning is a health problem causing severe illness and even death. Food poisoning caused by bacteria from food in Indonesia there are about 20 million cases of food poisoning per year. Around 600 million people worldwide fall ill after eating contaminated food, and 420,000 fatal cases occur every year. The most common disease caused by ingestion of contaminated food is diarrheal disease, which causes 550 million people to fall ill and 230,000 fatal cases every year. In Helvetia Medan there are 41 people who have had food poisoning and are undergoing treatment. treated at Medan Hospital after eating dinner at the hostel on Tuesday, February 8, 2017. The impact of food poisoning can cause several complications from mild to more serious. The most common complication is dehydration, while the more serious complication is hemolytic uremic syndrome. The method used in this research is descriptive method, with a total sampling technique of 48 people. The results show that the publi...

This paper focuses on the comparison of some probability distributions for low wind speeds regimes using some goodness-of-fit criteria. Results obtained from the analysis indicated that while the 2-parameter Weibull distribution reported the best fit in terms of its highest p-value of the Kolmogorov-Smirnov (K-S) statistic, the Akaike information criterion (AIC) reported the 4-parameter transformed beta distribution as the best model for the wind speed observations. Further, the 1-parameter Maxwell distribution presented the best Q-Q plot of all the fitted distributions. The results from the study also suggest that several other probability distributions can be used as efficient alternative to the conventional Weibull distribution in fitting wind speeds data from low wind speeds zones.

Bacterial cellulose (BC) is a flexible biopolymer having valuable properties like high purity (without hemicellulose and lignin), high percentage of crystallinity, water retention, mechanical strength, biodegradability and unique biocompatibility. Unlike plant cellulose, bacterial cellulose is produced by many bacterial species. Recent advances in research have identified several producers of BC but the key producer is Komagataeibacter xylinus. BC produced from K. xylinus is known to possess captivating structural, physical, and chemical properties, hence making it a significant natural polymer to be used for future innovative research purposes. This review paper discusses the structural and physicochemical properties of BC; its natural production from bacteria as well as its production under optimized culture conditions. Since the demand for useful composites is high, the involvement of BC in the development of BC-based composites has also been discussed in detail in this paper. Th...

Precise characterization of the compactability of aggregates and soils in the laboratory has always been a challenge to pavement technologists. The present study investigated compactability of aggregates and soils through the comparison of three laboratory compaction methods, the Superpave Gyratory Compactor, the Marshall impacting hammer, and a vibratory compacting machine. Accelerometers were attached to the Marshall impacting hammer and a laboratory scale vibratory compactor to capture the dynamic response of soils and aggregates during compaction. The results from this comparative experiment indicated that there was a consistent relationship between the stiffness of soils and aggregates and the dynamic responses from impaction and vibration, which can be used to better characterize the compactability of different paving materials through laboratory testing.

For gyratory compaction, the concept of the locking point was initially developed to identify the compactability of asphalt mixes and to alleviate potential aggregate crushing in the mold. Most previous studies on the locking point were based on specimens’ height change. Recent studies have indicated that the gyratory locking point of cold mix asphalt mixtures could be determined by the rotation angle range indicator using SmartRock. However, height or rotation angle change ultimately reflects a change in volume. Additionally, there is no clear physical and mechanical connection between the volume change and the gyratory locking point. In this paper, a stone mastic asphalt mixture (SMA 13) was selected for gyratory compaction applying various compaction temperatures. The compaction data were recorded by a SmartRock embedded in different positions. Collected data included stress, rotation angle, and acceleration. The major findings are as follows: (1) the specimen’s locking point cou...

Pelayanan pengangkutan barang oleh kapal dituntut supaya sampai tujuan dengan selamat, tepat, ekonomis serta pelayanan yang memuaskan, oleh karena itu untuk menunjang kelancaran pelayaran di laut sangat dibutuhkan sejumlah kapal yang memenuhi persyaratan. Satu diantara komponen yang memiliki peranan adalah peranan kompresor udara tidak bisa diabaikan begitu saja, karena kompresor udara mempunyai kegunaan yang sangat luas, baik dibutuhkan untuk menjalankan motor induk, motor bantu, kontrol pneumatik maupun untuk udara kerja dibagian mesin maupun bagian deck. Untuk bekerja maksimal, kompresor udara perlu diperhatikan terhadap perawatan dan perbaikan, terutama keahlian serta pemahaman seorang masinis yang berperan penting dalam kelancaran operasional kapal. Dari uraian bab per bab yang telah dijelaskan sebelumnya dapat diambil kesimpulan bahwa kompresor udara tidak bisa bekerja secara optimal disebabkan oleh tidak tercapainya tekanan udara start mesin induk pada saat olah gerak dan kur...

Ekosistem mangrove di wilayah Karangsong Kabupaten Indramayu merupakan salah satu ekosistem hasil rehabilitasi yang dimanfaatkan menjadi kawasan ekowisata. Penelitian dilaksanakan pada bulan Agustus 2018 di Kawasan Ekowisata Karangsong Kabupaten Indramayu guna mengetahui kondisis ekosistem mangrove dengan menggunakan metode Transek Line Plot (TLP). Stasiun pengamatan diambil berdasarkan waktu rehabilitasi dan  keterwakilan wilayah pada bagian selatan, bagian tengah dan bagian utara kawasan ekowisata mangrove Karangsong. Berdasarkan hasil penelitian, terdapat komposisi jenis dari dua spesies mangrove yaitu Avicennia marina dan Rhizophora mucronata. Kerapatan pada tingkat pohon di ekosistem mangrove Karangsong termasuk kedalam kategori rusak pada seluruh stasiun dengan nilai kerapatan masing-masing sebesar 633 ind/ha untuk stasiun 1, 366 ind/ha untuk stasiun 2 dan 100 ind/ha stasiun 3, tetapi menuju perkembangan kearah yang lebih baik ditunjukan dengan nilai kerapatan yang tinggi pada...

Coastal salt marshes along the northern Gulf of Mexico shoreline received varied types and amounts of weathered oil residues after the 2010 Deepwater Horizon oil spill. At the time, predicting how marsh bacterial communities would respond and/or recover to oiling and other environmental stressors was difficult because baseline information on community composition and dynamics was generally unavailable. Here, we evaluated marsh vegetation, physicochemistry, flooding frequency, hydrocarbon chemistry, and subtidal sediment bacterial communities from 16S rRNA gene surveys at 11 sites in southern Louisiana before the oil spill, and resampled the same marshes three to four times over 38 months after the spill. Calculated hydrocarbon biomarker indices indicated that oil replaced native natural organic matter (NOM) originating from Spartina alterniflora and marine phytoplankton in the marshes between May 2010 and September 2010. At all the studied marshes, the major class- and order-level s...

Tree diversity improves forest productivity Experimental studies in grasslands have shown that the loss of species has negative consequences for ecosystem functioning. Is the same true for forests? Huang et al. report the first results from a large biodiversity experiment in a subtropical forest in China. The study combines many replicates, realistic tree densities, and large plot sizes with a wide range of species richness levels. After 8 years of the experiment, the findings suggest strong positive effects of tree diversity on forest productivity and carbon accumulation. Thus, changing from monocultures to more mixed forests could benefit both restoration of biodiversity and mitigation of climate change. Science , this issue p. 80

This paper presents an optimization approach of calibrating a tomato greenhouse energy model using hybrid Evolutionary Programming (EP)-EnergyPlus. The proposed methodology applies automated simulation-based approach by coupling Matlab and EnergyPlus to perform building energy simulation and obtain the best variables configuration with minimal error between the simulated and measured energy of the greenhouse. The proposed method is tested using a tomato greenhouse system located in Universiti Putra Malaysia (UPM). The greenhouse envelope is built using 0.15mm thick Transparency Plastic Film. Meanwhile, the electrical loads in the greenhouse consists of 6 exhaust fans, 2 axial fans, 5 fluorescent lamps and 1 irrigation pump. An Evolutionary Programming (EP) algorithm is chosen and programmed in Matlab to find the best configurations for optimum calibration of the greenhouse energy model. Three variables were chosen to find the best configuration which are the operating hours of Exhau...

This study evaluated the aquifer protective capacity of Lambata in Kwali area council of Abuja, using electrical resistivity method. The obtained data were interpreted manually by partial curve matching and the obtained results were iterated using WINREIST software. The first layer is the topsoil whose resistivity range from 127.7 to 562.4 Ωm and its thickness range from 0.7 to 1.6 m. The second layer is laterite and its resistivity range from 302.3 to 937.6 Ωm, the thickness of the second layer range from 3.7 to 13.3 m. The third layer is a clay formation whose resistivity range from 46.7 to 88.8 Ωm and its thickness range from 6.6 to 27.9 m. The fourth layer is a weather/ fractured basement, this layer is the aquifer and it is confined by the overlying clay formation. Its resistivity range from 59.0 to 870.2 Ωm, while its thickness range from 6.0 to 28.5 m.  The fifth layer is the fresh basement whose resistivity range from 1038.5 to 4992.5 Ωm. The total longitudinal conductance v...