Environmental Engineering

The impact of ultrasound (US) on membrane filtration and cleaning were studied and compared at various operating parameters of nominal pore sizes of 10 and 100 kDa membrane, trans-membrane pressure (TMP) of 100 and 140 kPa, and US frequencies of 20 kHz and 40 kHz. An average of 15%–20% increase of permeability was observed when US (20 kHz) was applied to assist membrane filtration on 10 kDa membrane and 100 kPa trans-membrane pressure (TMP). However, an insignificant improvement was observed in the case of larger pore size membrane at higher TMP (140 kPa). US also augmented the membrane cleaning process effectively. Lower frequency 20 kHz US exhibited a higher flux recovery (>90%) than the high frequency 40 kHz (59%) using the 10 kDa pore size membrane with US-assisted membrane cleaning. Important factors influencing optimization of US effectiveness lie heavily on its configuration and operation. The experimental results as supported with SEM images demonstrate that US-assisted filtration and cleaning are most effective when membrane pore size, US frequency, and TMP are lower.

ABSTRACT
Nowadays, drainage networks, whether that was wastewater or storm water drainage networks are considered as one of the necessary infrastructure basics in modern cities. This research is focusing on planning and designing one drainage network “for a dual purpose” instead of the two networks that used one for wastewater and the other one for rainwater drainage, as they are called separated Drainage networks. Therefore, this network is working on wastewater and on the rainwater drainage on the same time. That reduces the cost by reducing amount of excavations and number of the pipes as well the wages for the workers who work on that project. This network would be perfect in Arab countries like Iraq because the amount of the rainfall is not that much and it happens only on the winter season for almost two or three months, not like the other western countries or Australia.
This research is following the global standardization in finding the optimal way of the designing a network such as finding the pipe slope and velocity of the water inside the pipes. Also, to compare it with minimum and the maximum velocity permitted, as well as finding the discharges and levels of pipes’ places in trenches and that depending on essential principles of designing of the network.
The research also includes the planning, designing and drawing a typical longitudinal sections for the Arab city and to be considered as a model that could be used for the planning and designing for any other cities according to the least possible cost.
All in all, the most important characteristic of this research is to adopt the discharging of more than a pipe in one direction within the inspection room so as to minimize the amount of excavation and reduce the diameters of the large pipes. For example, instead of choosing a pipe with a large diameter we can use two or more pipes with less diameter and that consider as a special feature worthwhile when you do not desire to the use of large diameters or the unavailability of that kind of pipes.

Considerably long periods of time are required to measure soil-water characteristic curves using conventional equipment such as pressure plate apparatus or a Tempe cell. A commercially available, small-scale medical centrifuge with a swinging type rotor assembly was used to measure the soil-water characteristic curves on statically compacted, fine-grained soil specimens. A specimen holder was specially designed to obtain multiple sets of water content versus suction data for measuring the soil-water characteristic curve at a single speed of rotation of the centrifuge. The soil-water characteristic curves were measured for three different types of fine-grained soils. The three soils used in the study were processed silt (liquid limit, wL = 24%; plasticity index, Ip = 0; and clay = 7%), Indian Head till (wL = 35.5%, Ip = 17%, and clay = 30%), and Regina clay (wL = 75.5%, Ip = 21%, and clay = 70%). The soil-water characteristic curves for the above soils were measured in 0.5, 1, and 2 ...

Palm kernel shell biochars (PKSB) ejected as residues from a gasifier have been used for solid fuel briquette production. With this approach, palm kernel shells can be used for energy production twice: first, by producing rich syngas during gasification; second, by compacting the leftover residues from gasification into high calorific value briquettes. Herein, the process parameters for the manufacture of PKSB biomass briquettes via compaction are optimized. Two possible optimum process scenarios are considered. In the first, the compaction speed is increased from 0.5 to 10 mm/s, the compaction pressure is decreased from 80 Pa to 40 MPa, the retention time is reduced from 10 s to zero, and the starch binder content of the briquette is halved from 0.1 to 0.05 kg/kg. With these adjustments, the briquette production rate increases by more than 20-fold; hence capital and operational costs can be reduced and the service life of compaction equipment can be increased. The resulting product satisfactorily passes tensile (compressive) crushing strength and impact resistance tests. The second scenario involves reducing the starch weight content to 0.03 kg/kg, while reducing the compaction pressure to a value no lower than 60 MPa. Overall, in both cases, the PKSB biomass briquettes show excellent potential as a solid fuel with calorific values on par with good-quality coal. Abbreviations: CHNS: carbon, hydrogen, nitrogen, sulfur; FFB: fresh fruit bunch(es); HHV: higher heating value [J/kg]; LHV: lower heating value [J/kg]; PKS: palm kernel shell(s); PKSB: palm kernel shell biochar(s); POME: palm oil mill effluent; RDF: refuse-derived fuel; TGA: thermogravimetric analysis ARTICLE HISTORY Nomenclature Roman D diameter of sample [m] F maximum force applied to break sample in tensile crushing strength test [N] H height of sample [m] Greek s radial tensile crushing strength [N/m 2 ]

Construction and demolition waste is one of the important category of solid waste. Many recreational and building projects contribute towards generation of ample quantity of waste produced on these respective sites. Reutilisation of the construction and demolition waste can be very beneficial in terms of various managing and operational parameters on a construction site. This paper emphasises upon study ofassessment of reutilization of various categorical waste from constructional site situated at different geographical areas. Numerous types of waste generated from these respective sites are taken into consideration and their reutilisation on the same site is focussed which resulted in reducing cost, labour work and wastage of the materials. By-product formation from the reutilisation of waste generated from these types of constructional arena is being focussed upon. Further recommendations in terms of the future scope of the study are given at the end of the paper.

An efficient and new but non-intrusive method to detect the fluctuation in gear load may be the motor current signature analysis (MCSA). In this paper, a multi-stage transmission gearbox (with and without defects) has been studied in order to replace the conventional vibration monitoring by MCSA. It has been observed through FFT analysis that low frequencies of the vibration signatures have sidebands across line frequency of the motor current whereas high frequencies of vibration signature are difficult to be detected. Hence, discrete wavelet transform (DWT) is suggested to decompose the current signal, and FFT analysis is carried out with the decomposed current signal to trace the sidebands of the high frequencies of vibration

Wind energy is one among the most promising renewable energy sources, and hence there is fast growth of wind energy farm implantation over the last decade, which is expected to be even faster in the coming years. Wind turbine blades are complex structures considering the different scientific fields involved in their study. Indeed, the study of blade performance involves fluid mechanics (aerodynamic study), solids mechanics (the nature of materials, the type of solicitations …), and the fluid coupling structure (IFS). The scope of the present work is to investigate the mechanical performances and structural integrity of a large offshore wind turbine blade under critical loads using blade element momentum. The resulting pressure was applied to the blade by the use of a user subroutine “DLOAD” implemented in ABAQUS finite element analysis software. The main objective is to identify and predict the zones which are sensitive to damage and failure as well as to evaluate the potential of c...

Megaprojects are large, they are constantly growing ever larger, and more and more are being built in what has been called the biggest investment boom in history. This chapter serves as an introduction to megaprojects, and to The Oxford Handbook of Megaproject Management. First, megaprojects are defined and the size of the global megaprojects business is estimated. Second, drivers of the megaproject boom are identified, including monumentalism and the technological sublime. Third, ten things you must know about megaprojects are detailed, from their tendency to suffer from uniqueness bias to their overexposure to black-swan events. Fourth, the "iron law of megaprojects" is identified as a main challenge to megaproject management: "Over budget, over time, under benefits, over and over again." Finally, the main structure of the Handbook is set out as covering the what, the why, and the how of megaproject management, in terms of the challenges, causes, and cures that students of megaprojects must decipher to better understand and better manage megaprojects.

The book points out that rural regions need proper attention at the global level concerning solid waste management sector where bad practices and public health threats could be avoided through traditional and integrated waste management
routes. Solid waste management in rural areas is a key issue in developing and transitioning countries due to the lack of proper waste management facilities and services. The book further examines, on the one hand, the main challenges in the development of reliable waste management practices across rural regions and, on the other hand, the concrete solutions and the new opportunities across the world in dealing with municipal and agricultural wastes. The book provides useful information for academics, various professionals, the members of civil society, and national and local authorities.

The globally escalating thyroid nodule incidence rates may be only partially ascribed to better diagnostics, allowing for the assessment of environmental risk factors on thyroid disease. Endocrine disruptors or thyroid-disrupting chemicals (TDC) like bisphenol A, phthalates, and polybrominated diphenyl ethers are widely used as plastic additives in consumer products. This comprehensive review studied the magnitude and uncertainty of TDC exposures and their effects on thyroid hormones for sensitive subpopulation groups like pregnant women, infants, and children. Our findings qualitatively suggest the mixed, significant (α = 0.05) TDC associations with natural thyroid hormones (positive or negative sign). Future studies should undertake systematic meta-analyses to elucidate pooled TDC effect estimates on thyroid health indicators and outcomes.