Failure Analysis and Robust Optimization of an Exhaust Manifold Diffuser Plate

Diffuser plates in exhaust system manifolds are designed to provide uniform flow pattern within the manifold for maximum utilization of the catalytic converter substrate during high-temperature applications. In this paper, failure analysis of a diffuser which survived only 20% duration of a manifold crack test and various design optimization studies of the diffuser plate using computer-aided engineering (CAE) analyses are presented. During the manifold crack test, the failure occurred at the inner and outer periphery of the diffuser. Metallurgical failure analysis coupled with CAE thermal fatigue analysis of the component concluded that thermal fatigue was the root cause of the failure. The new recommended robust design showed considerable improvement in the thermal durability of the diffuser plate assembly.     

Electrochemical Corrosion and Impedance Studies of Porous Ti–xNb–Ag Alloy in Physiological Solution

Porous titanium (Ti) and its alloys are promising materials for orthopedic applications due to their low elastic modulus, high strength, excellent corrosion resistance, and biocompatibility. In this study, the porous Ti–xNb–5Ag (x = 25, 30 and 35 wt%) alloys were synthesized using the powder metallurgy approach. The effects of Nb content on the porosity, mechanical properties, and electrochemical corrosion behavior of the alloys were investigated. XRD analysis revealed that the porous alloys mainly consist of α-Ti, β-Ti, intermetallic compound (Ti₄Nb), and oxides of TiO₂ and NbO phases. Porous alloys possess the porosity ranging from 57 to 65%, due to the addition of NH₄HCO₃ (45 wt%). Increase in Nb content lead to a reduction in the elastic modulus and compression strengths of the sintered porous Ti–xNb–5Ag alloys. All three developed porous Ti–xNb–5Ag alloys show the optimum combination of elastic modulus and compression strength, which is suitable for orthopedic applications. These porous alloys exhibit excellent electrochemical corrosion resistance in the simulated body fluids, and the samples having low porosity exhibit higher corrosion resistance than high-porosity samples.

     

$$E^{2} SR^{2}$$ E 2 S R 2 : An acknowledgement-based mobile sink routing protocol with rechargeable sensors for wireless sensor networks

Wireless Networks - The advances in hardware manufacturing technologies and wireless communications enabled the evolution of tiny, multi-functional, low-power and resource constrained sensor nodes...     

Design and development of enhanced bandwidth multi‐frequency slotted antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐band applications

A multi‐frequency rectangular slot antenna for 4G‐LTE/WiMAX/WLAN and S/C/X‐bands applications is presented. The proposed antenna is comprised of rectangular slot, a pair of E‐shaped stubs, and an inverted T‐shaped stub and excited using staircase feed line. These employed structures help to achieve multiband resonance at four different frequency bands. The proposed multiband slot antenna is simulated, fabricated and tested experimentally. The experimental results show that the antenna resonates at 2.24, 4.2, 5.25, and 9.3 GHz with impedance bandwidth of 640 MHz (2.17‐2.82 GHz) covering WiMAX (802.16e), Space to Earth communications, 4G‐LTE, IEEE 802.11b/g WLAN systems defined for S‐band applications. Also the proposed antenna exhibits bandwidth of 280 MHz (4.1‐4.38 GHz) for Aeronautical and Radio navigation applications, 80 MHz (4.2‐4.28 GHz) for uncoordinated indoor systems,1060 MHz (5.04‐6.1 GHz) for the IEEE 802.11a WLAN system defined for C‐band applications and 2380 MHz (7.9‐10.28 GHz) defined for X‐band applications. Further, the radiation patterns for the designed antenna are measured in anechoic chamber and are found to agree well with simulated results.     

1174: futuristic trends and innovations in multimedia systems using big data,IoT and cloud technologies (FTIMS)

Multimedia Tools and Applications -     

适用于长距离输电网络的通用电压崩溃指标

首先提出一个广义电压崩溃指标（Generalized Voltage Collapse Index,缩写为GVCI）,定义为含有大容抗的长距离辐射型输电系统（架空线或海底电缆）距离最大稳定极限负荷的当前负荷裕度．GVCI为瞬时值,可用于保护和控制装置的整定,通过相量测量单元（PMU）所提供的局部测量值实现控制和保护功能．用一个简单的两母线双回线系统对所提出的GVCI指标的有效性进行了测试,通过扩展GVCI,用解析方式分析有载调压变压器（OLTC）的运行对电压崩溃的影响;并将GVCI与分析电压崩溃时常用的L指标进行了比较,讨论GVCI在地理位置偏远的风力发电场的可能应用．     

Routine production or symbolic analysis? India and the globalisation of architectural services

Developments in information technology have reduced the need for spatial proximity in the geography of architectural employment: computer-based drafting allows for better standardisation and more efficient production of project information, whilst electronic communication links make the immediate transfer of this information possible across long distances. The ability to compress time and space may be paving the way to the relocation of architectural production facilities from higher-wage to lower-wage regions: numerous examples already exist of firms that have adopted this strategy to reduce their overheads.

Thus far, discussion of the viability and desirability of this emerging trend has been hampered by its close focus on the type of work carried out, and a consequently narrow view of its costs and benefits. Remote drafting is seen as a cheap form of professional north-south exploitation in architecture's intellectual circles that should be ignored if not deplored. By stressing the connection between the task and the culture in which it is developed, this paper seeks to produce a broader, alternative perspective, which identifies the several limitations of current off-shore collaborations but also points out possible future strengths, development strategies, and necessary environmental conditions.

The Indian context provides an opportunity to highlight analogies and differences between the recent growth of the export-oriented IT industry and the construction of a colonial professional practice at the turn of the twentieth century. If properly acknowledged by the domestic profession and considered by policy-makers, the development of a framework for distant architectural collaborations could be used not only to support the local design sector and bring the contested components of its post-colonial tradition in sharper focus and possibly closer together, but also to respond to the many challenges posed by the country's economic policies, growth, and infrastructural conditions.     

A nanoscale friction investigation during the manipulation of nanoparticles in controlled environments

Future micro/nanodevices will contain very small features such that liquid lubrication is not practical and inherent lubricity is needed. In this study, a nanoscale friction investigation was carried out during the manipulation of Au and SiO(2) nanoparticles on silicon using atomic force microscopy (AFM). Nanoparticle sliding was characterized by quantifying the lateral force associated with the AFM tip twisting as it hits the particle edge. The friction force varies with particle area and humidity, illustrating how meniscus forces on nanoparticles affect friction. A large tip slid on the nanoparticle-coated surface exhibited friction reduction due to nanoparticle sliding and contact area reduction.     

Optimization of Fenton-biological treatment scheme for the treatment of aqueous dye solutions

Degradation of dyes especially, azo dyes are difficult due to their complex structure and synthetic nature. The main objective of this study was to evaluate the Fenton-biological (aerobic) treatment train for decolorization and mineralization of azo dyes viz. Reactive Black 5 (RB5), Reactive Blue 13 (RB13) and Acid Orange 7 (AO7). The objective of Fenton treatment was only to decolorize the dyes (breakage of -NN-), as it was considered that after breakage of -NN-, the dyes will become amenable to biodegradation and can be further treated in aerobic biological system. Hence studies were carried out to optimize the lower Fenton's doses for decolorization of dyes. The optimum doses for decolorization (>95%) of all the three dyes were found out to be 15 mgL(-1) of Fe(2+) (0.27 mM) and 50 mgL(-1) (1.47 mM) of H(2)O(2) dose at optimum pH 3. Further it was also investigated that at lower doses, the main problem of Fenton process (sludge generation) can also be minimized. Later the mineralization of the dye (removal of aromatic amines) was achieved in the aerobic biological treatment system. Overall reduction of 64, 89 and 75% in the aromatic amines (at 254 nm), 88, 95 and 78% in naphthalene ring associated compounds (near 310 nm) and 49, 89 and 91% reduction in benzene ring associated compounds (near 226 nm) were observed for RB5, RB13 and AO7, respectively. Thus this treatment system seems to be quite effective and economical option for the treatment of recalcitrant compounds like dyes, as the cost in the chemical treatment is considered mainly due to chemicals thus at lower doses the operational cost is saved. Further, as the sludge generation was almost negligible at lower doses, thus the savings in cost of handling and disposal of hazardous sludge also adds to economy of treatment.     

Micro/nanomechanical characterization of ceramic films for microdevices

Microelectromechanical systems (MEMS) are currently fabricated using single-crystal silicon, various polysilicon films and other ceramic materials. Silicon carbide (SiC) film has recently been pursued as a material for use in MEMS devices owing to its excellent mechanical properties and high-temperature capabilities. Since physical and chemical properties, friction and wear are important issues in such small-scale devices, it is essential that the materials used in MEMS have good micro/nanomechanical and tribological properties. Micro/nanomechanical characterization of single-crystal 3C-SiC (cubic or β-SiC) films, undoped and doped (n⁺-type) polysilicon films have been carried out. For comparision, measurements on undoped single-crystal Si(100) have also been made. Hardness, elastic modulus and scratch resistance of these materials were measured by nanoindentation and microscratching using a nanoindenter. Fracture toughness was measured by microindentation using a microindenter. Friction and wear properties were measured using an accelerated ball-on-flat tribometer. It is found that the 3C-SiC film exhibits higher hardness, elastic modulus and scratch resistance as well as lower friction compared to other materials. These results show that the 3C-SiC film possesses desirable micro/nanomechanical properties that make it an ideal material for use in MEMS devices.