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This paper provides an analytical assessment of the feasibility of wind energy for Saudi Arabia's envisioned NEOM city, which plans to use only renewable energy. A probability density function was fit to winds simulated for the NEOM region during 2014‐2018. Using this distribution, the optimal wind turbine was selected as the one with the largest capacity factor and smallest levelized cost of energy (LCOE). Financial, environmental, and risk analysis of a wind farm consisting of 100 of these units was also performed. A Weibull distribution determined by changing the shape and scale parameters to minimize the mean squared error offered the best fit to the measured wind speeds at this location. The estimated power density showed that the NEOM site warrants a Class 3 classification, which means wind energy systems would be suitable for commercial operation. A 3.2‐MW wind turbine, which is optimal for this location, has a capacity factor varying from 31.9% to 41.4% and LCOE that ranges from 6.99¢ to 8.32¢ per kWh. The 320‐MW wind farm has a positive net present value, a simple payback period of 13.8 years, and a LCOE of 6.6¢ per kWh. By installing this farm, potential annual savings of CO2 are around 106 metric tons. [ABSTRACT FROM AUTHOR]

This paper examines the bio-derived stabilization of sand-only or sand-plus-silt soils using an extracted bacterial enzyme application to achieve induced calcite precipitation (ICP). As compared to conventional microbial induced calcite precipitation (MICP) methods, which use intact bacterial cells, this strategy that uses free urease catalysts to secure bacterial enzyme–induced calcite precipitation (BEICP) appears to offer an improved means of bio-stabilizing silty-sand soils as compared to that of MICP processing. Several benefits may possibly be achieved with this BEICP approach, including bio-safety, environmental, and geotechnical improvements. Notably, the BEICP bio-stabilization results presented in this paper demonstrate (i) higher rates of catalytic urease activity, (ii) a wider range of application with sand-plus-silt soil applications bearing low-plasticity properties, and (iii) the ability to retain higher levels of soil permeability after BEICP processing. Comparative BEICP versus MICP results for sand-only systems are presented, along with BEICP-based results for stabilized soil mixtures at 90:10 and 80:20 percentile sand:silt ratios. This BEICP method's ability to obtain unconfined compressive strength results in excess of 1000 kPa with sand-plus-silt soil mixtures is particularly noteworthy. [ABSTRACT FROM AUTHOR]

Furthermore, the discussers' equation presents a relationship between UCS and the porosity/cement index that are suitable for portland cement stabilized soils via mixing method. Soils and portland cement are mixed uniformly at their dry states during the stabilization process, whereas the biocementation stabilization adopts a percolation circulation technique that solidifies the specimen column from top to bottom. Portland cement stabilization and biocementation stabilization techniques' working mechanisms are different and equations developed for predicting UCS of portland cement stabilized soils may not be directly applicable to soils stabilized using biocementation techniques. [Extracted from the article]

This paper addresses a soil bio-stabilization technique using bacterial enzyme-induced calcium carbonate precipitation (BEICP) as an alternative to previous conventional methods including microbial-induced carbonate precipitation and plant-derived enzyme-induced carbonate precipitation. The extracted urease enzyme of viable S. pasteurii was used as a biological source along with calcium chloride and urea to solidify sandy soil and silty sand soil. The bio-treated soil columns were subjected to freeze and thaw (F–T) cycling for a durability evaluation. Engineering properties of bio-cemented soil including unconfined compressive strength, calcium carbonate contents, moisture contents, porosity, permeability, and microstructure were examined before and after the F–T durations. It was found that although bio-stabilizer was able to increase a frost duration of soil, the F–T cycling significantly impacted on the compressive strength of bio-treated soil, due to a formation of microcracks. This investigation has revealed that the BEICP method provided a similar capacity in F–T resistance of soil as using the traditional Portland cement stabilizer, whereas the class F fly ash did not improve F–T durability of medium dense soil. [ABSTRACT FROM AUTHOR]

Abstract: The USEPA''s 2010 mercury rule, which would reduce emissions from non-hazardous waste burning cement manufacturing facilities by an estimated 94%, represents a substantial regulatory challenge for the industry. These regulations, based on the performance of facilities that benefit from low concentrations of mercury in their feedstock and fuel inputs (e.g., limestone concentration was less than 25ppb at each facility), will require non-compliant facilities to develop innovative controls. Control development is difficult because each facility''s emissions must be assessed and simple correlation to mercury concentrations in limestone or an assumption of ‘typically observed’ mercury concentrations in inputs are unsupported by available data. Furthermore, atmospheric emissions are highly variable due to an internal control mechanism that captures and loops mercury between the high-temperature kiln and low-temperature raw materials mill. Two models have been reported to predict emissions; however, they have not been benchmarked against data from the internal components that capture mercury and do not distinguish between mercury species, which have different sorption and desorption properties. Control strategies include technologies applied from other industries and technologies developed specifically for cement facilities. Reported technologies, listed from highest to lowest anticipated mercury removal, include purge of collected dust or raw meal, changes in feedstocks and fuels, wet scrubbing, cleaning of mercury enriched dust, dry sorbent injection, and dry and semi-dry scrubbing. The effectiveness of these technologies is limited by an inadequate understanding of sorption, desorption, and mercury species involved in internal loop mercury control. To comply with the mercury rule and to improve current mercury control technologies and practices, research is needed to advance fundamental knowledge regarding mercury species sorption and desorption dynamics on materials within cement facilities. [Copyright &y& Elsevier]

Abstract: The concept of “universal service obligation” (USO) has been around for decades; however, its definition continues to change. The notion that the last mile of fixed-line access should be subsidized has spread around the world, despite well reasoned arguments and empirical evidence that the policy is and was a failure. It created artificial competition. Now the concept is becoming bifurcated. Should wireless and/or broadband services be included in the definition of universal services? The purpose of the paper is to demonstrate why the definition should be expanded, although a definitive prescription is not offered. This paper is in two parts: What should constitute USO definitions and how, if at all, it should be implemented? Many consumers are “cutting-the-cord” and moving directly to alternative services. In this ubiquitous communications environment the whole set of possible communications methods should be considered when defining “universal connectivity.” Second, no one service or technology should be relied on to support subsidies. The second part of the paper addresses the policy question: How should this connectivity be achieved? [Copyright &y& Elsevier]

Focuses on the use of real options analysis to address issues of regulation. Impact of regulation on investment; Discussion on generic real options analysis; Application of real options to telecommunications.

Discusses the value of real options theory for the telecommunications industry in the U.S. Use of discounted cash flow (DCF) method in project evaluation and investments; Application of real options methodology in DCF analysis; Implications of real options theory for policymakers.

Written by a former corporate manager pursuing counseling as a 2nd career, this article offers pointed views on managed mental health care. Values of practitioners that are a mismatch for managed care are noted, and more specific disadvantages and advantages are examined. Loss of client confidentiality is addressed and procedures and technologies for its reclamation are noted. Negative effects on therapy are acknowledged and potential for better accountability and research are pointed out. Economic disadvantages of a small provider's practice as well as opportunities for creating new value and additional income are reviewed. The relatively sudden emergence of managed care is credited with a natural time lag preceding regulatory responses. Acknowledging that most new practitioners have little choice about the clients they serve, the article concludes that it would be shortsighted to rule managed care out of one's practice. [ABSTRACT FROM AUTHOR]

• Thassos marble used extensively as cool pavement at Al Masjid Al-Haram, Makkah City, Saudi Arabia. • Thassos marble provides unique thermophysical properties due to its dolomitic composition. • Thassos marble also offers unique 'snow white' color which matches sacred purity of prominent Al Masjid Al-Haram religious site at Makkah City. This paper presents a thermophysical assessment of the extraordinary 'snow white' dolomitic marble material being used for pavement, wall, and even roofing surfaces within the Al Masjid Al-Haram (i.e., Great Mosque) in Makkah City, Saudi Arabia. Extensive use of this extremely white marble with exterior pavements helps maintain a cool surface which is conducive to the site's religiously obligatory barefoot pedestrian contact. Modelled analysis of this site's expected diurnal marble pavement surface temperature during both summer and winter periods was derived using local seasonal weather data. These results conceptually confirmed this marble's remarkable ability to maintain desirable cool-surface conditions even during peak summertime solar insolation periods. Comparative analyses of surface temperatures and energy transfer were also derived for the same site and weather conditions based on the possible alternative use of conventional paving options (e.g., concrete and asphalt). In this case, modelling results indicated that either of the concrete or asphalt options would have generated far hotter surfaces which would be unacceptable, and perhaps even dangerous for bare skin contact, during summer months. [ABSTRACT FROM AUTHOR]

Addresses the prevalence of providing psychotherapy over the Internet. Ethical issues surrounding the phenomenon; Factors to be considered by clinicians deciding to work online; Opportunity of the prospect of online mental health care treatment.

A progressive freeze concentration (PFC) process was applied to treat several waters where clean ice was generated one-dimensionally, and salt and impurities concentrate into the liquid phase. The impact of eight process parameters on salt percent removal and ice percent recovery were investigated. They were coolant temperature, stirring rate, advance speed of crystallizer, feed solution concentration, feed solution temperature, ice seeding, crystallizer material, and mixing flow pattern. The significant process parameters found were stirring rate, coolant temperature, and feed solution concentration. Temperature difference between feed solution temperature and coolant temperature is important in minimizing supercooling which has a negative effect on treatment. For example, our results showed a temperature difference of 10 °C for a feed solution temperature of 2.5 °C were needed to minimize supercooling. Salt percent removal was found to be directly related to while ice percent recovery was inversely related to the stirring rate. Treatment of an artificial seawater (salinity 35.67 g/L) and a RO brine concentrate (salinity 2600 mg/L) resulted in 51% and 70% ice percent recovery and 74% and 97.7% salt percent removal, respectively. An application of the PFC process includes brine concentrate treatment for inland desalination plants. [ABSTRACT FROM AUTHOR]

Wastewater disinfection is practiced with the goal of reducing risks of human exposure to pathogenic microorganisms. In most circumstances, the efficacy of a wastewater disinfection process is regulated and monitored based on measurements of the responses of indicator bacteria. However, inactivation of indicator bacteria does not guarantee an acceptable degree of inactivation among other waterborne microorganisms (e.g., microbial pathogens). Undisinfected effluent samples from several municipal wastewater treatment facilities were collected for analysis. Facilities were selected to provide a broad spectrum of effluent quality, particularly as related to nitrogenous compounds. Samples were subjected to bench-scale chlorination and dechlorination and UV irradiation under conditions that allowed compliance with relevant discharge regulations and such that disinfectant exposures could be accurately quantified. Disinfected samples were subjected to a battery of assays to assess the immediate and long-term effects of wastewater disinfection on waterborne bacteria and viruses. In general, (viable) bacterial populations showed an immediate decline as a result of disinfectant exposure; however, incubation of disinfected samples under conditions that were designed to mimic the conditions in a receiving stream resulted in substantial recovery of the total bacterial community. The bacterial groups that are commonly used as indicators do not provide an accurate representation of the response of the bacterial community to disinfectant exposure and subsequent recovery in the environment. UV irradiation and chlorination/dechlorination both accomplished measurable inactivation of indigenous phage; however, the extent of inactivation was fairly modest under the conditions of disinfection used in this study. UV irradiation was consistently more effective as a virucide than chlorination/dechlorination under the conditions of application, based on measurements of virus (phage) diversity and concentration. Taken together, and when considered in conjunction with previously published research, the results of these experiments illustrate several important limitations of common disinfection processes as applied in the treatment of municipal wastewaters. In general, it is not clear that conventional disinfection processes, as commonly implemented, are effective for control of the risks of disease transmission, particularly those associated with viral pathogens. Microbial quality in receiving streams may not be substantially improved by the application of these disinfection processes; under some circumstances, an argument can be made that disinfection may actually yield a decrease in effluent and receiving water quality. Decisions regarding the need for effluent disinfection must account for site-specific characteristics, but it is not clear that disinfection of municipal wastewater effluents is necessary or beneficial for all facilities. When direct human contact or ingestion of municipal wastewater effluents is likely, disinfection may be necessary. Under these circumstances, UV irradiation appears to be superior to chlorination in terms of microbial quality and chemistry and toxicology. This advantage is particularly evident in effluents that contain appreciable quantities of ammonia-nitrogen or organic nitrogen. [ABSTRACT FROM AUTHOR]

Aliphatic amines can be found in many wastewater effluents from industry, agriculture, pharmacy, and food processing. Amines can induce toxicological responses that are relevant in biochemical treatment processes, as well as in natural waters. This research compared the toxicity and inhibition caused by three aliphatic amines (n-propylamine, ethylmethylamine, and trimethyl-amine) and their chlorinated derivatives. The chemistry of chlorine interactions with these compounds was characterized by using membrane introduction mass spectrometry (MIMS). Acute toxicity assays were conducted by using a Microtox® system with Phosphobacterium phosphoreum (also known as Vibrio fischeri) for the aliphatic amine compounds and their corresponding chlorinated derivatives, as identified by MIMS. Inhibition tests were conducted by using the oxygen utilization rate test with an enhanced nitrifier culture. The median effective concentration (EC50) values for chloropropylamine, chloroethylmethylamine, and chlorodimethylamine obtained by Microtox with a contact time of 15 min were 12.68, 19.72, and 15.92 µM, respectively. The EC50 values of these aliphatic chloramines from the Microtox test decreased by roughly one order of magnitude as a result of chlorination. Inhibition of nitrifiers also was observed in these amines. Trimethylamine and n-propylamine caused greater inhibition to nitrifiers than did ethylmethylamine under similar concentrations. Nitrifier inhibition from these amines increased after chlorination. The results of these tests indicated that aliphatic amines and their chlorinated derivatives could induce environmentally relevant toxicity responses in treatment settings and in receiving waters. [ABSTRACT FROM AUTHOR]