Developing sustainable residential buildings in Saudi Arabia: A case study

This paper assesses the energy and water consumption practices of existing housing in Saudi Arabia, with the ultimate aim of establishing guidelines for delivering sustainable residential buildings in the near future. In order to achieve this aim the current status of a typical Saudi residence (i.e. an apartment complex) is investigated in terms of energy and water consumption using simulation software packages. The paper then examines the prospects for applying various measures to the typical Saudi residence to manage energy and water use more sustainably. This research identifies several design-related faults common to Saudi Arabian house design. These faults contribute to an inefficient use of energy and domestic water resources. Finally, the paper puts forward a set of recommendations and guidelines, design-related and otherwise, to enhance the sustainability of future Saudi residential buildings.     

Multi-Attribute Selection Procedures Based on Regret and Rejoice for the Decision-Maker

Feelings influence human beings’ decision-making; therefore, incorporation of feeling factors in decision-making is very important. Regret and rejoice are very important emotional feelings that can have a great impact on decision-making if they are considered together. While regret has received most of the attention in related research, rejoice has been less considered even though it can greatly influence people’s preferences in decision-making. Furthermore, systematically incorporating regret and rejoice in the multi-criteria decision-making (MCDM) modeling frameworks for decision-making has received little research attention. In this paper, we introduce a new multi-attribute selection procedure that incorporates both regret and rejoice to select the best choice. We utilize the positional advantage operator concept to develop regret and rejoice mathematical equations, and prove them. The proposed MCDM procedure that incorporates these two emotional factors offers a decision-maker the flexibility to trade off some benefits in order to gain a state of psychological satisfaction. More specifically, regret and rejoice are presented mathematically to enable the decision-maker to determine the values of regret and rejoice, and then make the decision in which the rejoice value is higher than the regret value. To test the performance of this new procedure, we apply it to three numerical examples proposed in previous works. The results are matched with those obtained by other methods such as the regret model, VIKOR, PROMETHEE I, and PROMETHEE II, thereby proving the efficacy of the new procedure.     

创业国度以色列的创新哲学

正以色列的创新生态系统是一个从发明到创新的过程,由初创企业、工程师、研究型大学、风险投资、政府支持和大企业六大要素组成并相互作用以色列创新生态系统的六大要素创新是在一个生态系统中发生发展起来的,并且首先是在相对较小的地理空间内发生、生长起来的。可持续的技术创新是一个经济的概念,对于促进当地经济发展、创造就业机会和提高生活质量来说     

External perforated Solar Screens for daylighting in residential desert buildings: Identification of minimum perforation percentages

The desert climate is endowed by clear sky conditions, providing an excellent opportunity for optimum utilization of natural light in daylighting building indoor spaces. However, the sunny conditions of the desert skies, in countries like Egypt and Saudi Arabia, result in the admittance of direct solar radiation, which leads to thermal discomfort and the incidence of undesired glare. One type of shading systems that is used to permit daylight while controlling solar penetration is “Solar Screens”. Very little research work addressed different design aspects of external Solar Screens and their influence on daylighting performance, especially in desert conditions, although these screens proved their effectiveness in controlling solar radiation in traditional buildings throughout history.This paper reports on the outcomes of an investigation that studied the influence of perforation percentage of Solar Screens on daylighting performance in a typical residential living room of a building in a desert location. The objective was to identify minimum perforation percentage of screen openings that provides adequate illuminance levels in design-specific cases and all-year-round.Research work was divided into three stages. Stage one focused on the analysis of daylighting illuminance levels in specific dates and times, while the second stage was built on the results of the first stage, and addressed year round performance using Dynamic Daylight Performance Metrics (DDPMs). The third stage addressed the possibility of incidence of glare in specific cases where illuminance levels where found very high in some specific points during the analysis of first stage. The research examined the daylighting performance in an indoor space with a number of assumed fixed experimentation parameters that were chosen to represent the principal features of a typical residential living room located in a desert environment setting.Stage one experiments demonstrated that the screens fulfilled the requirements of the majority of tested cases. Illuminance levels in the examined residential space were satisfactory in 83% of the near zone cases and 53% in the mid-length zone, while the far zone suites 40% of the cases. Screen influence on daylighting was found to be very much dependent on the orientation of the window and time of the day.In stage two, the percentage of annual “Daylight Availability” was very much related to screen perforation percentage. As perforation percentage decreased, the percentage of Daylit and Over lit spaces decreased. At the same time, Partially Daylit areas of the space increased with similar percentages irrespective of the orientation. As a result of the twofold research stages, it is recommended to utilize a minimum of 80% perforation percentages for spaces similar to the tested case in the South orientation.In stage three, an initial investigation suggests that the use of screens can significantly reduce the occurrence of glare phenomena. Also, it is suggested to study the efficiency of designing Solar Screens that have non-uniform perforation ratios. These could prove useful in improving the illuminance levels in the mid-length and far zones of the unsatisfactory cases.In conclusion, minimum perforation percentages for Solar Screens were presented for specific design cases that encompassed different orientations, seasons and time of the day. In addition, a tool that could be used by architects for based on required annual “Daylit” areas for the design of Solar Screens that effectively achieve functional needs was provided.     

Functionalization of polymethylhydrosiloxane gels with an allyl ureido benzocrown ether derivative: Complexation properties

Crosslinked polymethylhydrosiloxane (PMHS) thin films prepared by sol–gel polycondensation have been functionalized by Pt‐catalyzed hydrosilylation of SiH groups with an allyl ureido crown ether precursor. To this purpose, both 4′‐allylurea‐benzo‐15‐crown‐5 ( 1 ) and 1‐allyl‐3‐propyl‐urea ( 2 ) were synthesized and characterized. We have shown that competitive side‐reactions occurred following hydrosilylation due to the hydrolysis of part of the SiH groups resulting in the formation of new crosslinks Si(CH₃)O_3/2 as shown by solid‐state ²⁹Si‐NMR. This is explained by the deactivation of the Pt catalyst toward hydrosilylation by amide groups. For thin films (～ 1 μm) prepared on silicon wafers, a quantitative method based on FT‐IR transmission spectroscopy was used to measure the crosslinking density of the network, and the percentage of functionalization (SiC %) following hydrosilylation. The results are discussed in relation to the mesh size of the network, and the diffusion of alkenes and water molecules within lightly crosslinked PMHS gels obtained by varying the amount of triethoxysilane crosslinker (mol %) from 15 to 1%. The self‐organization properties of ureido groups by H‐bonding were studied by FT‐IR for the functionalized thin films. The complexation properties of the crown ether 1 ‐functionalized thin films were evidenced by using FT‐IR following diffusion‐reactions of NaSCN and KSCN salts in CHCl₃ : MeOH solvent mixtures within thin films. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Fabrication and characterization of bioactive glass (45S5)/titania biocomposites

Bioactive glass (BG) (45S5) has been used successfully as bone-filling material in orthopedic and dental surgery but its lean mechanical strength limits its applications in load-bearing positions. Approaches to strengthen these materials decreased their bioactivity. In order to realize the optimal matching between mechanical and bioactivity properties, bioactive glass (45S5) was reinforced by introducing titania (TiO₂) in anatase form and treated at 1000 °C to form new bioactive glass/titania biocomposites. The prepared biocomposites were assessed by XRD, FT-IR, mechanical properties and SEM. The results verified that the increase of titania percentage to BG powder enhanced gradually the mechanical data of the prepared biocomposites. SEM and FT-IRRS confirmed the presence of a rich bone-like apatite layer post-immersion on the composite surface. It has been found that the new BG/titania biocomposite materials especially those containing high content of titania have high bioactivity properties and compressive strength values comparable to cortical bone. Therefore, these biocomposite materials are promising for medical applications such as bone substitutes especially in load-bearing sites.     

Physiological and molecular study on the anti-obesity effects of pineapple (Ananas comosus) juice in male Wistar rat

Food Science and Biotechnology - The present study was performed to assess anti-obesity effects of raw pineapple juice in high fat diet (HFD)-induced fatness. Based on food type, rats were divided...     

Modeling the Axial Mechanical Response of Amorphous Fe45Ni45Mo7B3 Honeycombs

The high yield strength and elastic modulus of metallic glasses suggests they could perform an important role in structural applications. To produce materials with a high strength-to-weight ratio and excellent mechanical energy absorption, it is advantageous to form amorphous alloys as cellular solids. Using the elastic properties of slip cast amorphous Fe₄₅Ni₄₅Mo₇B₃ ribbons, a metallic glass honeycomb was manufactured with a unique manufacturing approach. First, prototypes were manufactured with a porosity of 97?pct, a cell wall thickness of 0.03?mm, and a cell size of 3?mm. Experimentally measured mechanical properties were reasonably similar to analytical models. This suggests that a three-times improvement in the yield strength along the out-of-plane direction is achievable when compared with crystalline aluminum honeycombs. An analytical model was developed to predict the relative density and the compressive stress (?? ₃ ^* ) in the out-of-plane (X ₃) direction of the ??teardrop?? cellular structure. The predictions are validated by initial experimental results and compare well with existing analytical models for hexagonal cellular materials.     

Linear-time border-tracing algorithms for quadtrees

In applications where the quadtree is used as an underlying object representation, a number of basic operations are implemented as a trace along the border of the object's region. A technique is presented that determines a way to shift any given scene (as well as its quadtree), so that the border of all the objects in the scene can be traversed in time proportional to the length of all the borders in the scene (or the number of blocks when the scene is represented as a quadtree). This determination is shown to be performed in time proportional to the length of all the borders in the scene. This allows the direct translation of a number of chain-code algorithms into quadtree algorithms without loss of asymptotic worst-case efficiency. This results in improved worst-case analyses of algorithms that convert chain codes into quadtrees and that perform connected component labeling of images represented as quadtrees.The support of the National Science Foundation under Grant IRI-88-02457 is gratefully acknowledged.     

Usage based service differentiation for end-to-end quality of service management

It is often difficult to ensure that every application in a computing environment receives the level of quality of service required by their users. In such cases, the demand for computing resources to do so simply exceeds the limited supply that is available. To ensure that at least some user applications meet quality of service requirements, service differentiation is one approach growing in popularity. In this approach, preferential service is given to selected applications, while others deemed less important suffer in comparison. Most work in this area bases service differentiation decisions on static information about the applications, such as the name and type of application, the owner of the application, execution time, and the host on which the application was executed. In this paper, we discuss a new approach to service differentiation that takes into consideration dynamic application usage information in service differentiation decisions. In doing so, we can make better or fairer service differentiation decisions that allow more users to enjoy higher levels of quality of service. This is accomplished by ensuring preferential service is given to applications whose users can actually benefit from the improved service, as opposed to those applications that are essentially ignored or in a state that renders them unusable.