Experimental Modeling of Gas–Solid Heat Transfer in a Pipe with Various Inclination Angles

Gas–solid flow in a pipe with different configurations (vertical, horizontal, and inclined positions) is studied experimentally. Air with temperature around 170°C and sand particles with mean diameter of 253 μm are used as gas and solid mediums, respectively. Effects of different parameters (pipe slope and solid particles feed rate) are studied on heat transfer rate between gas and solid particles. The Nusselt number decreases at lower solids feed rate in a dilute regime of the mixture; however, it increases at higher solids feed rates. Furthermore, results show that a higher Nusselt number takes place at the angles closer to 45 degrees.     

Standard ANSI Z9.14: Testing and performance verification methodologies for ventilation systems for Biological Safety Level 3 (BSL-3) and animal Biological Safety Level 3 (ABSL-3) facilities

The American Industrial Hygiene Association (AIHA) and the American National Standards Institute (ANSI) are developing a national standard titled “Testing and performance verification methodologies for ventilation systems for Biological Safety Level 3(BSL-3) and animal Biological Safety Level 3 (ABSL-3) laboratories” known as ANSI/AIHA Z9.14. The ANSI Z9.14 standard will focus on performance verification of engineering controls related specifically to ventilation system features of BSL-3/ABSL-3 facilities. Currently the design of these facilities is largely guided by the criteria defined in successive versions of the Biosafety in Microbiological and Biomedical Laboratories (BMBL),¹ while facilities funded by the National Institutes of Health (NIH) follow BMBL as well as the NIH Design Requirements Manual (DRM).² Among professionals such as architects, engineers, contractors, commissioning agents and owners who are asked to specify or perform tests for performance of ventilation systems in high containment facilities, there is a consensus that there is no comprehensive methodology based on a risk assessment of each individual facility. An extensive literature review was conducted to determine if there are any regulations, standards or guidance available that provide a “methodology” to verify that the ventilation systems in such facilities are performing appropriately for the current or potential future use. This ‘Gap and Needs Analysis’ provides evidence that there is no single resource for a comprehensive testing methodology that can be used uniformly from one facility to another to verify that the ventilation systems in such facilities are performing appropriately. ANSI Z9.14 can provide one component of a more extensive graduated, risk-based approach to reaching containment goals appropriate to the risk of the agent and the laboratory activity.     

Investigation of lanthanum and Si/Al ratio effect on the HZSM-5 catalyst efficiency for production of Olefin from Methanol

The effect of lanthanum and Si/Al ratio on catalytic performance of HZSM-5 in methanol to olefin process is investigated in this paper. The catalyst with bases of HZSM-5 is modified using the lanthanum by a wet impregnation producer. The Box-Behnken method, experimental design is used to evaluate effects of lanthanum parameters, Si/Al ratio, temperature and the effect of the interaction between them in methanol to olefin process for production of ethylene and propylene. Finally, the obtained results show the highest yield of ethylene is achieved for high load lanthanum catalyst, low Si/Al ratio and high temperature.     

Analysis of the strain process of soil slope model during infiltration using BOTDA

Rainfall infiltration can be a major cause of slope failure. In the present paper, an indoor soil slope model was built; a distributed sensing fiber was designed based on Brillouin optical time-domain analysis (BOTDA). Two soil moisture probes were planted and a rainfall infiltrationtest was simulated to acquire the data of slope infiltration and deformation progress under rainfall infiltration. Time domain volumetric moisture content of the slope as well as the vertical and horizontal strain changes were monitored. The moisture content results showed the infiltration path and had obvious ascent at the sliding surface of the slope. The fiber results showed that there existed an apparent strain concentration near the shear section of the slope and strain conversion zone; the soil deformation law had a close spatial relationship with the infiltration path in the soil. In addition to the accurate determination of the sliding surface, a secondary shear surface was also detected by the BOTDA system. These results provide valuable information pertaining to the sliding mechanism and prediction of slope failure.     

Attaining optimal dyeability and tensile properties of polypropylene/poly(ethylene terephthalate) blends with a special cubic mixture experimental design

In this investigation, we attempted to enhance the dyeability of polypropylene (PP) with disperse dyestuffs without adversely affecting its tensile properties. To this end, a special cubic experimental design was used to predict the effect of variations in the properties of a tricomponent mixture composed of PP, poly(ethylene terephthalate) (PET), and maleic anhydride grafted polypropylene (PP‐g‐MA) on the dyeability and tensile properties of the resultant polymer blend. The results illustrate that there seemed to be critical PET content, above which the blend's dye uptake tended to remain constant, but the tensile properties were adversely affected. Further analysis of the results indicated that the PP/PET/PP‐g‐MA blends in which the PET and PP‐g‐MA contents were in the range 10–15 and 4–5 wt %, respectively, gave maximal dye uptake and desirable tensile properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Design of a reversible structure for memory in quantum-dot cellular automata

Complementary metal oxide semiconductor (CMOS) technology has limitations in reducing the area and size of circuits. The disadvantages of this technology include high power consumption and temperature problems. Quantum-dot cellular automata (QCA) is a new technology that can overcome these shortcomings. Reversible logic is technology used to reduce the power loss in QCA. QCA can be used to design memories that require high operating speed. In this paper, we propose a structure for the reversible memory in QCA. The proposed structure utilizes three-layer technology, which has a significant impact on circuit size reduction. The proposed structure for the reversible memory has 63% improvement in cell number, a 75% improvement in area occupancy, and a 60% reduction in delay compared to the previous best structure.     

Machining of aerospace titanium alloys

The performance of PCBN (AMBORITE*) and PCD (SYNDITE) has been compared with that of coated tungsten carbide tool currently being used to machine titanium aerospace alloy. Tests confirm that SYNDITE gives a better surface finish, longer tool life and more manageable swarf than other tools. In addition, the “quick-stop” technique establishes that, for all three cutting tools, a layer is formed between the rake face and the underside of the emerging chip which has a fundamental effect on cutting and wear mechanisms.     

Water-Dispersible Pd–N-Heterocyclic Carbene Complex Immobilized on Magnetic Nanoparticles as a New Heterogeneous Catalyst for Fluoride-Free Hiyama,Suzuki–Miyaura and Cyanation Reactions in Aqueous Media

Catalysis Letters - Pd–N-heterocyclic carbine complex immobilized on magnetic nanoparticles is synthesized and characterized by different techniques such as FT-IR, XPS, TEM, EDX, FESEM, VSM,...     

Modeling and analysis of multiple impacts in multibody systems under unilateral and bilateral constrains based on linear projection operators

Multibody System Dynamics - This paper presents a unifying dynamics formulation for nonsmooth multibody systems (MBSs) subject to changing topology and multiple impacts based on a linear projection...