Flow and contaminant transport in an airliner cabin induced by a moving body: Model experiments and CFD predictions

The effects of a moving human body on flow and contaminant transport inside an aircraft cabin were investigated. Experiments were performed in a one-tenth scale, water-based model. The flow field and contaminant transport were measured using the Particle Image Velocimetry (PIV) and Planar Laser-Induced Fluorescence (PLIF) techniques, respectively. Measurements were obtained with (ventilation case) and without (baseline case) the cabin environmental control system (ECS). The PIV measurements show strong intermittency in the instantaneous near-wake flow. A symmetric downwash flow was observed along the vertical centerline of the moving body in the baseline case. The evolution of this flow pattern is profoundly perturbed by the flow from the ECS. Furthermore, a contaminant originating from the moving body is observed to convect to higher vertical locations in the presence of ventilation. These experimental data were used to validate a Computational Fluid Dynamic (CFD) model. The CFD model can effectively capture the characteristic flow features and contaminant transport observed in the small-scale model.     

Treatment of wastewater by electrocoagulation: a review

The electrocoagulation (EC) process is an electrochemical means of introducing coagulants and removing suspended solids, colloidal material, and metals, as well as other dissolved solids from water and wastewaters. The EC process has been successfully employed in removing pollutants, pesticides, and radionuclides. This process also removes harmful microorganisms. More often during EC operation, direct current is applied and electrode plates are sacrificed (dissolved into solution). The dissolution causes an increased metal concentration in the solution that finally precipitates as oxide precipitates. Due to improved process design and material of construction, the EC process is being widely accepted over other physicochemical processes. Presently, this process has gained attention due to its ability to treat large volume and for its low cost. The aim of this study is to review the mechanism, affecting factors, process, and application of the electrocoagulation process.     

Assessment of the impact of pesticide residues on microbiological and biochemical parameters of tea garden soils in India

The main aim of this study was to assess the impact of pesticidal residues on soil microbial and biochemical parameters of the tea garden soils. The microbial biomass carbon (MBC), basal (BSR) and substrate induced respirations (SIR), beta-glucosidase activity and fluorescein diacetate hydrolyzing activity (FDHA) of six tea garden soils, along with two adjacent forest soils (control) in West Bengal, India were measured. The biomass and its activities and biochemical parameters were generally lower in the tea garden soils than the control soils. The MBC of the soils ranged from 295.5 to 767.5 micro g g(- 1). The BSR and SIR ranged from 1.65 to 3.08 mu g CO2-C g(- 1) soil h(- 1) and 3.08 to 10.76 micro g CO2-C g(- 1)h(- 1) respectively. The beta-glucosidase and FDHA of the soils varied from 33.3 and 76.3 micro g para-nitrophenol g(- 1) soil h(- 1) and 60.5 to 173.5 micro g fluorescein g(- 1)h(- 1)respectively. The tea garden soils contained variable residues of organophosphorus and organochlorine pesticides, which negatively affected the MBC, BSR, SIR, FDHA and beta -glucosidase activity. Ethion and chlorpyriphos pesticide residues in all the tea garden soils varied from 5.00 to 527.8 ppb and 17.6 to 478.1 ppb respectively. The alpha endosulfan, beta endosulfan and endosulfan sulfate pesticide residues in the tea garden soils ranged from 7.40 to 81.40 ppb, 8.50 to 256.1 ppb and 55 to 95.9 ppb respectively. Canonical correlation analysis shows that 93% of the total variation was associated with the negative impact of chlorpyriphos, beta and alpha endosulfan and endosulfan sulfate on MBC, BSR and FDHA. At the same time ethion had negative impact on SIR and beta-glucosidase. Data demonstrated that the pesticide residues had a strong impact on the microbial and biochemical components of soil quality.     

Protection from steam at high pressures: development of a test device and protocol.

Extensive use of pressurized steam in the oil and gas sectors has led to incidents where workers were seriously injured. In this study a test device and procedure to measure heat transfer through fabrics during steam exposure were developed and evaluated. Several factors were considered while designing the test device to simulate work site conditions. Fabrics were exposed to steam at 2 distances (50 and 100 mm) and 2 pressures (207 and 69 kPa). Theoretical considerations included heat and mass transfer, and fabric structure and performance properties. The test device and procedure differentiated well among both fabrics and exposure conditions. For all fabrics, maximum heat transfer was observed at highest steam pressure and shortest distance. Laminated and coated fabrics performed better than a fabric without such treatments.     

Influence of cabin conditions on placement and response of contaminant detection sensors in a commercial aircraft

Potential causalities due to airborne disease transmission and risk of chem-bio terrorism in commercial airliner cabins can be reduced by fast responses. Fast responses are only possible by using sensors at appropriate locations in the cabins. Cost, size and weight factors restrict the number of sensors that could be installed inside a cabin. Since release locations and seating patterns of passengers can impact airborne contaminant transports, this study first addressed this impact by using a validated computational fluid dynamics (CFD) program in a four-row mockup of twin-aisle airliner cabin. It was observed that occupancy patterns and release locations have little influence on longitudinal contaminant transports though localized variations of contaminant concentrations may exist. The results show that response time of the sensors is considerably reduced with the increase in number of sensors. If only a single sensor is available across a cabin cross-section then it should be placed at the middle of the ceiling. A cabin model of a fully occupied twin-aisle airliner with 210 seats was also build to study the diverse contaminant distribution trends along cabin length. The results reveal that seating arrangements can make cross-sectional airflow pattern considerably asymmetrical. Similar airflow patterns make the longitudinal contaminant transport in the business and economy classes alike. The presence of galleys greatly affected the longitudinal transport of contaminants in a particular cabin section. The effects due to galleys were less significant if a multipoint sampling system was used. The multipoint sampling system can also reduce the number of sensors required in a cabin.     

Landslides in the Garhwal Lesser Himalaya, UP, India

The Garhwal Lesser Himalaya is one of the most fascinating segments of the Himalayan arc and in many ways quite unique in its geomorphological features and geological setting. Although it has a mild and mature topography in comparison with the Central and Outer Himalayas, with its deeply dissected valleys it is more immature than other areas such as the Himachal and Kumaon Lesser Himalayas. Debris flows, rock falls and slow mass rock movements are frequent within this part of the Himalayas. The frequent landslides in the area are controlled by the trends of the rocks and slopes, the structural features and the rock lithologies. Correlating all these factors, this paper illustrates how the slopes on the ridges parallel to the Himalayan trend (i.e. WNW–ESE) are the most susceptible for the mass failure.     

Two-tier Haddon matrix approach to fault analysis of accidents and cybernetic search for relationship to effect operational control: a case study at a large construction site.

The Haddon matrix is a potential tool for recognizing hazards in any operating engineering system. This paper presents a case study of operational hazards at a large construction site. The fish bone structure helps to visualize and relate the chain of events, which led to the failure of the system. The two-tier Haddon matrix approach helps to analyze the problem and subsequently prescribes preventive steps. The cybernetic approach has been undertaken to establish the relationship among event variables and to identify the ones with most potential. Those event variables in this case study, based on the cybernetic concepts like control responsiveness and controllability salience, are (a) uncontrolled swing of sheet contributing to energy, (b) slippage of sheet from anchor, (c) restricted longitudinal and transverse swing or rotation about the suspension, (d) guilt or uncertainty of the crane driver, (e) safe working practices and environment.     

Antennal Deformities of Chironomid Larvae and Their Use in Biomonitoring of Heavy Metal Pollutants in the River Damodar of West Bengal,India

Analyses of sediment and water indicate the presence of heavy metal pollutants like lead, zinc, copper, mercury and cadmium of the river Damodar of India. These metals are responsible for causing morphological deformities of antennae and other parts of chironomid larvae. Percentage of deformity correlated positively with the concentrations of Pb in water and sediment (r > 0.6) at the confluence point. A new severity index, SISS_(antenna) has been proposed here to assess deformity at the family or subfamily level.     

Synthesis and antimicrobial activity of esters of 3-ethoxy-4-hydroxybenzaldehyde oxime

A series of oxime esters was synthesized by esterification of 3-ethoxy-4-benzaldehyde oxime with acid chlorides in the presence of triethylamine. They were evaluated for their in vitro antifungal activity against three pathogenic fungi, namely Rhizoctonia bataticola, Fusarium udum, and Alternaria porii, and their antibacterial activity against the three bacterial strains Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoneae. The compounds bearing medium-length alkyl chains showed greater activity than those with long alkyl chains. An electron-donating group in para position of the aryl ring confers highest activity.