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Rapid prototyping (RP) technologies provide the ability to fabricate initial prototypes from various model materials. Stratasys' fused deposition modeling (FDM) is a typical RP process that can fabricate prototypes out of ABS plastic. Translucent plastics are commonly used in packaging for mechanical and electrical components. Although various materials are used in RP, translucent RP parts are not readily available from most RP processes. In this paper, two post‐processing techniques were applied in order to increase the optical transmissivity of the parts made of ABSi. First, elevated temperature was applied resulting in increased transmissivity while dimensional shrinkage was observed. Second, resin infiltration and surface sanding provided up to 16 percent transmissivity without shrinkage. These post‐processes can be selectively applied to increase the transmissivity of ABSi parts. Thus, translucent FDM parts can be fabricated from the regular FDM process followed by the post‐processes developed in this study.

Personal thermal management in functional textiles is in increasing demand for health care, outdoor activity and energy saving. Thus, developing new strategies is highly desired for radiative cooling and/or heating by manipulation of the transmissivity, reflectivity and absorptivity of the textiles within solar energy and human body heat radiation ranges.

Inorganic additives including TiO2, Fe2O3, carbon black (CB), graphene and mica were incorporated into polymer films. The inorganic additives' full spectrum properties and thermal responses were comprehensively investigated.

The CB composite film showed the highest absorptivity over the full solar to human body radiation spectrum. The mica-white (mica-w) (mica coated with TiO2) and mica-red (mica-r) (mica coated with Fe2O3) composites showed the lowest solar energy absorptivity and a strong body heat radiation reflectivity. Furthermore, according to composites' thermal responses to the simulated solar and human body radiations, CB and mica are promising for both cooling and heating when applied in dual-functional thermal management textiles.

Research has limitation related the amount of additives which can be added to textile. When powder is added to polyester yarn, the amount is limited by 2–3%. When powder is added to the composite which is used for printing, the amount of powder is limited by 5%.

A lot of apparel, especially sport apparel, contains prints. Decoration is one part of print application. Now, a lot of companies work under development of different additives, which provide additional properties to apparel. The closest targets for powder added to prints are cooling and heat retention. Quite often, inorganic additives possess dual properties: the inorganic additives may be heat reflective which his needed for heat retention, but may have high-thermal conductivity, which works well for cooling. Human body has complicated mechanism of heat exchange: convection, radiation and moisture evaporations play main role. The same additive may be cooling if there is a contact with skin but may be heating (IR reflective) if placed in the second or third layer. Thus, effect is needed to be studied first before real application.

This work could provide a comprehensive guideline for the rational design and application of thermal management composite textile materials by revealing the full solar to human body radiation performance of a series of inorganic materials.

Gaya, the holy city of Hindus, Buddhists and Jains, is facing an acute shortage of potable water. Although the city is blessed with some static and dynamic water bodies all around the region, they do not fulfill the requirement of millions of public either inhabitants of the area or tourists or pilgrims flocking every day. Countless crowds, congested roads, swarming pedestrians, innumerable vehicles moving throughout the day and night have made the city into a non-livable one. The present status of surface water is a mere nightmare to the requirements of the people. Due to which, massive ground water pumping mostly illegally has added a grid in addition to the other socio-economic issues.

To focus on such problem, the ground water of the region was studied thoroughly by calculating the depth of water level, discharge, pre-and post-monsoon water table and specifically the storativity in ten different locations. Some data were acquired, others were assessed, and few are calculated to provide an overall view of the ground water scenario.

After a long and tedious field study, it was finally established from that static water level ranges from 2.45 to 26.59 m, below ground level (bgl), discharge varies from 3.21 m³/day to 109.32 m³/day. Post pumping drawdown falls between 0.93 m and 16.59 m, whereas the specific capacity lies in between 0.96 and 7.78 m³/hr/m. Transmissivity, which is a key objective to assess ground water potential ranges from 109.8 to 168.86 m²/day.

This research work is original.

To investigate the influences of environmental stresses on board‐embedded polymeric waveguides.

Optical multimode waveguides were embedded on printed circuit boards using commercial polymers. The optical‐PCBs varying in board structure and in optical build‐up materials were exposed to heat, moisture and ionic‐contaminants in accelerated reliability tests. The influence of stress factors on the structural integrity and functional parameters, namely the refractive index and optical transmissivity, was investigated at the key communication wavelengths.

Isothermal annealing reduced the refractive index to the greatest extent. The optical‐PCB structure with an optical surface build‐up layer was observed to be more vulnerable under temperature shock when compared with the optical‐PCB with optical inner layer. The buffer layer beneath the optical build‐up was found to improve the stability of the optical waveguides significantly. The results indicated of wavelength dependence to the aging factor with a failure mechanism. The factors affecting the performance and reliability of polymer‐based optical waveguides on PCBs were discussed.

More experimental data and investigations of failure mechanisms are required to ultimately obtain sufficient reliability statistics for accurate life‐time prediction models.

Optical interconnects are seen as a promising solution to overcome performance limitations encountered with high‐frequency electrical interconnections. As an emerging technology, only a limited amount of reliability data on optical/electrical packages is available. The paper investigates the influences of environmental stresses on board‐embedded polymeric waveguides.

Introduction Laser‐based inspection systems originated in the late 1960s to automate the inspection task. Applied primarily to defect detection in flat, homogeneous products, these systems gained widespread use in the 1970s and through the 1980s. The bright, coherent light source provided the means to capture a range of defect optical effects including absorption, reflectivity, transmissivity, distortion and scattering. Unfortunately, early laser systems employed extremely inefficient light collection techniques. Much of the defects' optical information was lost. Fifteen to 20 years on, almost all commercial laser systems continue to employ this technology.

The finite strip method has been shown to apply to many problems in continuum mechanics. Within the constraints of the method, it has been shown to be superior to the finite element method in terms of data preparation, program complexity and execution time. The finite strip method has been recently extended to groundwater flow problems. The orthogonality of appropriately selected shape functions gives the finite strip method its computational efficiency. The uncoupling achieved from this orthogonality also produces a numerical method which is intrinsically parallel. Consequently, additional efficiencies can be obtained in a parallel environment. Numerical studies of the finite strip method to model a two‐dimensional groundwater flow problem demonstrate the accuracy of the solution and the superior performance of the numerical procedure in a parallel environment.

Aero-engine exhaust plume length can be more than the aircraft length, making it easier to detect and track by infrared seeker. Aim of this study is to analyze the effect of free stream Mach number (M_∞) on length of potential core of plume. Also, change in infrared (IR) signature of plume and aircraft surface with variation in elevation angle (θ) is examined.

Convergent divergent (CD) nozzle is located outside the rear fuselage of the aircraft. A two dimensional axisymmetric computational fluid dynamics (CFD) study was carried out to study effect of M_∞ on potential core. The CFD data with aircraft and plume was then used for IR signature analysis. The sensor position is changed with respect to aircraft from directly bottom towards frontal section of aircraft. The IR signature is studied in mid wave IR (MWIR) and long wave IR (LWIR) band.

The potential plume core length and width increases as M_∞ increases. At higher altitudes, the potential core length increases for a fixed M_∞. The plume emits radiation in the MWIR band, whereas the aerodynamically heated aircraft surface emits IR in the LWIR band. The IR signature in the MWIR band continuously decreases as the sensor position changes from directly bottom towards frontal. In the LWIR band the IR signature initially decreases as the sensor moves from the directly bottom to the frontal, as the sensor begins to see the wing leading edges and nose cone, the IR signature in the LWIR band slightly increases.

The novelty of this study comes from the data reported on the effect of free stream Mach number on the potential plume core and variation of the overall IR signature of aircraft with change in elevation angle from directly below towards frontal section of aircraft.

This paper aims to provide graduate students, researchers and government and independent agencies with an overview on BLEVE (i.e. boiling liquid expanding vapour explosion).

BLEVE has been studied by researchers, academicians, company specialists, and government and independent agencies. BLEVE incidents are collected from several sources such as technical and general articles, internet web sites and internal reports. BLEVE definitions, history, theory, types, hazards, and models are reviewed. BLEVE incidents are arranged and classified into fires, overfilling, explosions, overheating, runaways, overpressure, collisions, corrosion, and damage (derailment).

BLEVE types are classified into cold BLEVEs, hot BLEVEs, and BLEVEs. The major consequences of a BLEVE are thermal radiation from the resultant fireball and the fragments produced when the vessel fails. Several approaches are developed to describe BLEVE theory. BLEVE incidents are classified into explosions, damage (derailment), overfilling, fires, collisions, runaways, overpressure, overheating, and corrosion. The world has witnessed 74 BLEVE incidents in the period 1926‐1986. BLEVE incidents resulted in 1,427 fatalities and 635 injuries. The materials involved in BLEVE were flammable and non‐flammable. The highest frequencies of BLEVE incidents were due to explosions and damage to tanks. Explosion and damage BLEVE incidents resulted in high injuries. Overfilling and fire BLEVE incidents resulted in high fatalities.

This paper presents an overview of BLEVE definitions, history, incidents, types, theory, hazards and models. BLEVE incidents are classified. This paper combines scattered BLEVE incidents into one record.

This paper aims to present the implementation of a multi-layer radiation propagation model in simulations of multi-phase flow and heat transfer, for a dissociating methane hydrate reservoir subjected to microwave heating.

To model the induced heterogeneity due to dissociation of hydrates in the reservoir, a multiple homogeneous layer approach, used in food processes modelling, is suggested. The multi-layer model is incorporated in an in-house, multi-phase, multi-component hydrate dissociation simulator based on the finite volume method. The modified simulator is validated with standard experimental results in the literature and subsequently applied to a hydrate reservoir to study the effect of water content and sand dielectric nature on radiation propagation and hydrate dissociation.

The comparison of the multi-layer model with experimental results show a maximum difference in temperature estimation to be less than 2.5 K. For reservoir scale simulations, three homogeneous layers are observed to be sufficient to model the induced heterogeneity. There is a significant contribution of dielectric properties of sediments and water content of the reservoir in microwave radiation attenuation and overall hydrate dissociation. A high saturation reservoir may not always provide high gas recovery by dissociation of hydrates in the case of microwave heating.

The multi-layer approach to model microwave radiation propagation is introduced and tested for the first time in dissociating hydrate reservoirs. The multi-layer model provides better control over reservoir heterogeneity and interface conditions compared to existing homogeneous models.

The purpose of this paper is to analyze the bulk energy transport processes in the build chamber environment before and during laser sintering (LS) to provide a basis for effective and accurate thermal control for the LS process. This leads to improved mechanical properties and geometrical tolerances for LS products and may be applied to optimize operation cycle times for the LS process.

Computational models with two levels of complexity were built to explore the heat transfer mechanisms in the LS process. In a one-dimensional model (1D), the powder performed as a semi-infinite solid and heater flux to the powder surface was modeled with a heater control law. A two-dimensional (2D) fluid/solid finite element model of the build chamber and powder bins provided insight into the thermal processes in the build chamber.

Numerical 1D simulations were verified with measurements from sensors embedded in the build chamber powder bed. Using a 2D model, computed powder surface temperatures during the warm up and build phases were verified with an infrared camera. Convective currents in the build chamber and non-uniformities in the distribution of temperature over the radiant heater surface were found to be substantial contributors to non-uniformities in the powder bed surface temperature.

Limited heat sources were analyzed. No three-dimensional model was built. Assumptions to decrease the part bed temperature difference were not tested.

These simulation and experimental results may be used to enhance thermal control and operation efficiency during the LS process and to improve LS product mechanical properties.