Temporal Trends Of Energy Consumption And CO2 Emissions In Riyadh, Saudi Arabia

The consumption of material, energy, and water resources is inextricably linked to population growth with a unique impact on urban areas, especially in light of significant investments in infrastructure to support urban development. Urban metabolism is becoming popular as it provides a framework accounting the mass and energy flows through a city. An urban metabolism study was conducted to estimate the inputs and outputs of energy and pollutants from Riyadh, Saudi Arabia. The objective of this study was to determine the energy consumption of Riyadh using locally generated data from 1986, 1996, 2006, and 2012 and analysing the temporal trends of energy consumption and associated environmental impact. The socioeconomic and biophysical characteristics of Riyadh are well represented in its metabolism indicators. The high growth rate in population along with urban expansion has resulted in an increase in energy consumption. Riyadh has seen an increase in energy consumption at a rate of about 6% per annum. On a per capita basis, preliminary results show that the energy consumption increased by 31% from 1996 to 2012. Also, per capita CO2 emissions have increased by the same percentage. Results also show increasing mobile energy consumption from 20k TJ in 1986 to 157k TJ in 2012, which points to Riyadh’s inefficient urban form. The study findings highlight the importance for developing effective policies for improving the use of resources

Resolution of Overlapping Ultrasonic Echoes using Consistent Frequency Domain Amplitude-Phase Relationships

The ability to identify overlapping echoes is crucial to the enhancement of temporal resolution in ultrasonic testing. The majority of the techniques currently being investigated for separation of overlapping ultrasonic echoes are based on deconvolution. However, single reference deconvolution techniques are sensitive to the choice of the reference waveform and dictionary based deconvolution techniques require the enforcement of sparsity conditions. We propose a new post-processing algorithm that exploits the consistent frequency domain amplitude and phase relationships of two overlapping echoes. The frequency amplitude profiles are used as inputs and the corresponding set of phase values are calculated as the outputs. An example of the time profile and phase difference between two overlapping echoes are shown in Figure 1. The suitability of the output phase responses are then used as a metric to determine the accuracy of the trial amplitude inputs. Compared to dictionary based deconvolution approaches, the proposed method has a reduced search space in the optimization problem as the phases are now by-products of the algorithm. Compared to single reference deconvolution schemes this method is applicable to a much wider variety of echo combinations

Multi-megahertz IPT systems for biomedical devices applications

This paper investigates the main design constraints for the optimisation of an inductive power transfer (IPT) link for recharging implantable medical devices [1], and presents the potential advantages of operating in the multi-MHz range for such applications. The design proposed in this paper offers a fast charging solution, allowing patients to recharge their active medical implants every 4-5 years for 40% of its battery capability. The main challenge consists of obtaining good coupling and effective Q factor of the receiver coil, while minimizing the overall increase in size of the medical implant. Analysis obtained through electromagnetic simulations with CST Studio Suite for a 13.56 MHz, 1 W system suggests that it is possible to achieve a relatively high theoretical link efficiency of 66%, while keeping surface temperature increases and specific absorption rate (SAR) within the limits established in EN 45502 [2] and ICNIRP 1998 [3]. The experimental results show two feasible systems with different separation distances between the device's metallic case and the receiver coil, achieving transfer efficiencies [11] of 41% and 53% for separations of 1 mm and 7 mm, respectively

Adjustment for shape restoration and force control of cable arch stayed bridges

Cable arch stayed bridges are one type of tensile structures, and there are increasingly such structures constructed. Their performance relies on how they are designed. This type of structures can suffer big deflections under load, in this situation the displacements may need to be reduced. Sometimes, it may be necessary to control internal force of a specific cable so the cable force remains within the desired limit. More study need to be done to develop the techniques that are available for such adjustments. This paper deals with theoretical and experimental adjusting of two physical models, and the linear and nonlinear geometrical behavior of cable (arch) stayed bridges. It was concluded that the techniques of adjustment were practical and efficient to reduce, eliminate shape distortion, and control internal bar force of both structures. For structures that behave linearly, it is easier to get the target (displacement or force), but for non-linear structures one iteration of adjustments was not enough to get the displacement target. Through the techniques of the internal bar force adjustment, the amount of force can be reduced even to the zero, e.g. in case of replacing damaged members

937-2 Safety and Efficacy of QW3600 (EchoGen®) in Producing LV Opacification During Stress Echocardiography in Normals

QW 3600 (EchoGen®) (EG) is a new ultrasonic contrast agent which produces intense LV cavity and even myocardial opacification following IV injection in animals. However, no data exists regarding the potential of this agent to be used in conjunction with stress echo in humans. Therefore, in 17 normals we compared the results of injecting equal volumes of normal saline and progressive doses of EG: 0.02 cc/kg (5 pts). 0.05cc/kg (4). and 0.1cc/kg (8) during stress echo performed to 85% of maximal heart rate. Echo was performed in apical 4 chamber view, and LV contrast opacification was assessed qualitatively (1 + weak and incomplete, 2+ complete cavity. 3+dense and complete) and by videodensitometry (0.3cm2) region of interest in mid cavity. All subjects tolerated the injections well without adverse events. No significant changes were observed in pulse oximetry, the ECG, or 25 laboratory studies. We analyzed the maximal change (Δ) in systolic (S) and diastolic (D) pressure (mmHg) and heart rate (HR) and peak videointensity (PVI) from baseline to post exertion following the injection of either saline or EG (Table, all p=NS for saline vs EG except PVI)DoseSalineEGΔHRΔSBPΔDBPPVIΔHRΔSBPΔDBPPVI0.0248431813424917280.0537351611434321420.13740191037441962LV opacification was absent with saline, was inconsistent at 0.02 and 0.05cc/kg doses, but was≥ 2+ in all but one 0.1cc/kg administration (mean 2.4). Peak LV videointensity after EG was 62 for 0.1cc/kg. Thus, EchoGen® is a new contrast agent which is well tolerated when used with stress echo in normals and results in complete LV opacification at a dose of 0.1cc/kg. EchoGen® should prove to be a useful adjunct to clinical stress echo

Photooxidation of 2-methyl-3-buten-2-ol (MBO) as a potential source of secondary organic aerosol

2-Methyl-3-buten-2-ol (MBO) is an important biogenic hydrocarbon emitted in large quantities by pine forests. Atmospheric photooxidation of MBO is known to lead to oxygenated compounds, such as glycolaldehyde, which is the precursor to glyoxal. Recent studies have shown that the reactive uptake of glyoxal onto aqueous particles can lead to formation of secondary organic aerosol (SOA). In this work, MBO photooxidation under high- and low-NO_x conditions was performed in dual laboratory chambers to quantify the yield of glyoxal and investigate the potential for SOA formation. The yields of glycolaldehyde and 2-hydroxy-2-methylpropanal (HMPR), fragmentation products of MBO photooxidation, were observed to be lower at lower NO_x concentrations. Overall, the glyoxal yield from MBO photooxidation was 25% under high-NO_x and 4% under low-NO_x conditions. In the presence of wet ammonium sulfate seed and under high-NO_x conditions, glyoxal uptake and SOA formation were not observed conclusively, due to relatively low (<30 ppb) glyoxal concentrations. Slight aerosol formation was observed under low-NO_x and dry conditions, with aerosol mass yields on the order of 0.1%. The small amount of SOA was not related to glyoxal uptake, but is likely a result of reactions similar to those that generate isoprene SOA under low-NO_x conditions. The difference in aerosol yields between MBO and isoprene photooxidation under low-NO_x conditions is consistent with the difference in vapor pressures between triols (from MBO) and tetrols (from isoprene). Despite its structural similarity to isoprene, photooxidation of MBO is not expected to make a significant contribution to SOA formation

A 13.56 MHz bidirectional IPT system with wirelessly synchronised transceivers for ultra-low coupling operation

This paper presents a high-frequency inductive power transfer (HF-IPT) system with bidirectional capability employing a new wireless synchronisation method. Synchronisation is achieved by transmitting a reference ultra high frequency tone (433.92 MHz) that is stepped down to 13.56 MHz in each transceiver. This allows the operating frequency to be locked across the two sides of the system. Afterwards, a phase search is performed looking for maximum power throughput, determining the phase at the point of resonance (i.e., no reflected reactances). The experimental implementation is achieved with two back-to-back Class EF coil-drivers driven by independent synchronisation circuits. In the experimental setup a constant input voltage is set for each of the two coil-drivers by implementing a source-sink configuration, emulating a bidirectional DC-DC conversion stage at each side. Experimental results show successful transceiver synchronisation, and 4 W were transferred from one end to the other and conversely at an ultra-low coupling of 1.6%. This proves that the combination of the load-independent Class EF transceivers and the synchronisation technique introduced herein is suitable for applications that require large tolerance to misalignment and air gaps larger than one coil diameter, such as in micro e-mobility