The recent air temperature rise in Kuwait

Recently, there is increasing concern in Kuwait regarding the frequent occurrences of harsh climate conditions with summer air temperature exceeding the 50°C mark. In particular, in the last 20 years, the maximum yearly temperature is persistently exceeding its mean value for the whole recorded period.In an effort to explain this phenomenon, a study was made on the surface air temperature records for the past three decades measured at Kuwait International Airport and at a nearby coastal station at Ras Al-Khafja. The analyses have demonstrated that the airport weather station is more influenced by urbanization than Ras Al-Khafja.The linear trend of the air temperature data for both stations consistently showed a cooling period until 1972, followed by a warming period with temperature increases in the range of 0.03–0.08°C yr⁻¹. This warming trend is believed to be partly due to global climate change and the rest is due to man-induced local change in climate caused by urbanization. The urban warming appears to be both a daytime and night-time phenomenon, with maximum, mean and minimum temperatures showing a considerable increase. It is estimated that urban warming accounts for 25% of the maximum temperature increase.     

Chilled ceiling and displacement ventilation aided with personalized evaporative cooler

This paper aims at studying the energy impact of a chilled ceiling displacement ventilation CC/DV system aided with a personalized evaporative cooler (PEC) directed towards the occupant trunk and face. A simulation model is developed for integrating the personalized cooler with the ascending thermal plume. The thermal model of the conditioned room air around the person is integrated with a segmental bioheat and thermal comfort model to predict the human thermal comfort.The model is validated with experimental data on the vertical temperature distribution in the room, and the recorded overall comfort perceived by surveyed subjects. Experimental results agreed well with predicted values of temperature and comfort level. When using personalized cooling, the DV supply air temperature can be as high as 24 °C while the PEC at flow rates of 3–10 l/s achieved similar comfort with a DV system at supply temperature of 21 °C. At equal thermal comfort level, the integrated CC/DV system, PEC model resulted in up to 17.5% energy savings compared to the CC/DV system without a PEC. When mixed air is used in the CC/DV system additional 25% savings in energy is realized when compared with energy used for the 100% fresh air without the PEC.     

Time reversal processing in ultrasonic nondestructive testing

In this paper, we present a novel and completely different approach to focusing on defects beneath plane or curved surfaces: the time reversal mirror method. The time reversal technique is based on the concept of time reversal of ultrasonic fields and takes into account both the phase and modulus information coming from the defect. This technique is self-adaptative and requires only the presence of a target in the solid sample. In highly scattering media, it is shown that the time reversal process allows a new approach to speckle noise reduction. Experimental results obtained with a 121-channel time reversal mirror on titanium and duralumin samples are presented. They demonstrate the ability of time reversal to compensate for the distortions induced by liquid-solid interfaces of different geometries and to detect small defects in a noisy background     

Eco-innovative design approach: Integrating quality and environmental aspects in prioritizing and solving engineering problems

This study proposes an eco-innovative design process taking into consideration quality and environmental aspects in prioritizing and solving technical engineering problems. This approach provides a synergy between the Life Cycle Assessment (LCA), the nonquality matrix, the Theory of Inventive Problem Solving (TRIZ), morphological analysis and the Analytical Hierarchy Process (AHP). In the sequence of these tools, LCA assesses the environmental impacts generated by the system. Then, for a better consideration of environmental aspects, a new tool is developed, the non-quality matrix, which defines the problem to be solved first from an environmental point of view. The TRIZ method allows the generation of new concepts and contradiction resolution. Then, the morphological analysis offers the possibility of extending the search space of solutions in a design problem in a systematic way. Finally, the AHP identifies the promising solution(s) by providing a clear logic for the choice made. Their usefulness has been demonstrated through their application to a case study involving a centrifugal spreader with spinning discs.     

Effect of pre‐cooling of inlet air to condensers of air‐conditioning units

Energy conservation and increase in performance of air‐conditioning systems could be achieved by pre‐cooling the air intake of the condensers. This paper experiments three different methods of pre‐cooling the condenser air; the cooling pad (CP) setup, the cooling mesh (CM) setup and the shading setup. The CP and CM setups are two different methods of evaporatively cooling the air. The three methods have been applied to three identical, 2.8 tons, split air‐conditioning units during the peak summer time period in Kuwait, under ambient temperatures ranging from 39 to 45°C. The results yielded a drop in the power consumption ranging from 8.1 to 20.5% and an increase in the cooling load ranging from 6.4 to 7.8% by using the CP and CM setups, which, in turn, resulted in an increase in the coefficient of performance (COP) of the units by 36–59%. The shading setup has resulted in an increase of power consumption due to air trapped below the shaded area, which resulted in heat being generated. Copyright © 2005 John Wiley & Sons, Ltd.     

Lead removal from aqueous solutions by a Tunisian smectitic clay

The adsorption of Pb(2+) ions onto Tunisian smectite-rich clay in aqueous solution was studied in a batch system. Four samples of clay (AYD, AYDh, AYDs, AYDc) were used. The raw AYD clay was sampled in the Coniacian-Early Campanian of Jebel A?doudi in El Hamma area (South of Tunisia). AYDh and AYDs corresponds to AYD activated by 2.5 mol/l hydrochloric acid and 2.5 mol/l sulphuric acid, respectively. AYDc corresponds to AYD calcined at different temperatures (100, 200, 300, 400, 500 and 600 degrees C). The raw AYD clay was characterized by X-ray diffraction, chemical analysis, infrared spectroscopy and coupled DTA-TGA. Specific surface area of all the clay samples was determined from nitrogen adsorption isotherms. Preliminary adsorption tests showed that sulphuric acid and hydrochloric acid activation of raw AYD clay enhanced its adsorption capacity for Pb(2+) ions. However, the uptake of Pb(2+) by AYDs was very high compared to that by AYDh. This fact was attributed to the greater solubility of clay minerals in sulphuric acid compared to hydrochloric acid. Thermic activation of AYD clay reduced the Pb(2+) uptake as soon as calcination temperature reaches 200 degrees C. All these preliminary results were well correlated to the variation of the specific surface area of the clay samples. The ability of AYDs sample to remove Pb(2+) from aqueous solutions has been studied at different operating conditions: contact time, adsorbent amount, metal ion concentration and pH. Kinetic experiments showed that the sorption of lead ions on AYDs was very fast and the equilibrium was practically reached after only 20 min. The results revealed also that the adsorption of lead increases with an increase in the solution pH from 1 to 4.5 and then decreases, slightly between pH 4.5 and 6, and rapidly at pH 6.5 due to the precipitation of some Pb(2+) ions. The equilibrium data were analysed using Langmuir isotherm model. The maximum adsorption capacity (Q(0)) increased from 25 to 25.44 mg/g with increasing temperature from 25 to 40 degrees C. Comparative study between sulphuric acid activated clay (AYDs) and powder activated carbon (PAC) for the adsorption of lead was also conducted. The results showed that sulphuric acid activated clay is more efficient than PAC.     

THERMAL COMFORT ANALYSIS INSIDE A CAR

Owing to the hot harsh weather conditions in Kuwait during the summer months, the ambient temperature inside a car parked in the sun may reach 50°C and the temperature may reach 75°C. As a result, people are seriously concerned about how to keep their cars cool. This paper addresses the behaviour of the air temperature inside a car parked in the sun. Different covering arrangements were tested, including covering the front windshield, covering the front windshield and four side windows, and covering both windshields and four side windows. In addition, the novel idea was also tested of installing a solar powered ventilating fan. Such a technique was found to be very effective in reducing the inside air temperature of a car parked in the sun. The effects of the covering arrangements of the car and the solar fan on the initial cooling rate of an air-conditioning system during normal driving conditions were also analysed. Different physical parameters, namely air velocity, mean radiant temperature and humidity, were combined with air temperature to determine the comfort level of a person inside a car. © 1997 by John Wiley & Sons, Ltd.     

Mood and personality-based models of substance use.

Mood and personality-based vulnerabilities have been extensively examined in patients with substance use disorders, but their relevance as models of etiology remains to be fully investigated. The present investigation examined mood and personality-based models of substance use in a nonclinical sample of young adults. Two-hundred and twelve individuals were assessed for personality and clinical characteristics and participated in computerized ambulatory monitoring of mood states and substance use over a 1-week period. Personality factors were strong predictors of substance use frequency over the previous 30 days, as well as of substance use in daily life using ambulatory monitoring. A linear increase was also observed in the intensity of novelty seeking and antisocial personality traits as a function of the social deviance of substances used. However, mood disorder history was related only to the use of illicit drugs other than cannabis, and fluctuations in mood states did not prospectively predict daily use of substances in a manner consistent with self-medication. Moreover, there was little evidence that personality characteristics moderated relations between mood states and substance use in daily life. The relevance of results for mood and personality models of substance use etiology is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mineralogical and Geochemical Characterization of Mine Tailings and Pb, Zn, and Cd Mobility in a Carbonate Setting (Northern Tunisia)

Millions of tonnes of Pb–Zn ore flotation tailings and waste rock have been discharged at sites in northern Tunisia without concern for environmental issues. The tailings are dominantly fine grained (<125 μm), with high porosity and permeability. The tailings were characterized to assess base metal (Pb, Zn, and Cd) mobility. The relatively low percentage of iron sulphide and the dominance of carbonates in the matrices of the tailings indicated that only neutral mine drainage is likely. Batch sequential testing showed that the calcium and sulphate, which are the major ionic species in solution, are derived mainly from the dissolution of gypsum and not from neutralization of acidity generated by pyrite oxidation. Yet, despite the carbonate setting, the resultant neutral to slightly alkaline pH, and prolonged weathering, the studied flotation tailings maintain their capacity to release contaminants, notably Zn and Cd, into the environment. The amount of Zn that dissolves (2,400 μg L^?1, on average), though significant, is below the background concentrations in the Mejerda River and the environmental norms established for surface waters. Pb concentrations come close to the standards, but only Cd (18 μg L^?1, on average) sometimes exceeds current river water concentrations and environmental standards.