78 research outputs found

    Study of Polymer Binders to Develop Low Emissive Paints for Thermal Radiation Management Applications

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    347-353The management of thermal emittance always possess challenges in both military and civil domains. The low emissive materials in form of paints offers viable solution for minimising thermal emittance of military objects for camouflage and enhancing infrared reflectivity of roof to reduce cooling loads. Binder apart from pigments is one of the critical components of low emissive paint formulation to decide its ultimate performance. For selection of appropriate resin and binder, a comparative study of five prevalent polymers viz. polyurethane (PU), poly vinyl chloride (PVC), polyethylene (PE), polypropylene (PP) and poly methyl methacrylate (PMMA) has been carried out. Polymeric film of thickness 100μm of each of the polymer is prepared by Elcometer 4340 motorized film applicator. Infrared spectra and thermogravimetric profile have been obtained by Bruker make Tensor 27 FTIR in spectral range 4000 – 600 cm-1 and TGA Q 500. Film formation of PU is excellent and transmission in 3-5 μm is almost 100%. Hence, it may be chosen as binder in low emissive paint for MWIR band. PVC and PMMA among the polymers offer excellent transmission 87-99% in both thermal transmission windows 3-5 μm and 8-12 μm. Thermogravimetric (TG) profile of polymer films evident of thermal stability of PVC, PMMA and PU polymers up to 200 °C. Infrared transmission, TG profile and film formability manifest that both binders- PVC and PMMA are suitable for development of low emissive paints applicable up to temperature 200 °C for both IR transmission windows to evade thermal detectors working for detection of military objects and reducing cooling load in buildings by enhancing reflectivity of roof by application of low emissive paint

    Thermal resistance of two and three-layer fabric assemblies for extreme cold weather protective clothing 

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    Two (FA2) and three (FA3) layer fabric assemblies have been fabricated in different configurations using cloth shirting angola, pile acrylic fabric, non-woven polyester fabric (batting), coated nylon fabric and nappa leather for designing and development of multilayer clothing to provide protection in extreme cold weather. The configurations of FA2 are cloth shirting angola, PU coated nylon fabric; pile acrylic fabric, PU coated nylon fabric; cloth shirting angola, nappa leather; and acrylic pile fabric, nappa leather. On the other hand, the configurations of FA3 are cloth shirting angola, non-woven polyester fabric, PU coated nylon fabric; pile acrylic fabric, non-woven polyester fabric, PU coated nylon fabric; cloth shirting angola, non-woven polyester fabric, nappa leather; and pile acrylic fabric, non-woven polyester fabric, nappa leather. Thermal resistance of these multilayer clothing assemblies has been evaluated using high-resolution FLIR thermal imaging camera operating in 8-12µm waveband and PID controlled Acmas hot plate in natural convection mode. The maximum thermal resistance, offered by FA2 and FA3, are 5.59 and 6.24 tog respectively. Rational spatial configurations of FA2 and FA3 are as per the temperature of human body parts, and these may be used in designing and development of protective clothing for extreme cold weather

    Transcutaneous electrical nerve stimulation (TENS) for pain management in sickle cell disease.

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    BACKGROUND: Sickle cell disease (SCD), one of the most common inherited disorders, is associated with vaso-occlusive pain episodes and haemolysis leading to recurrent morbidity, hospital admissions and work or school absenteeism. The crises are conventionally treated with opioids, non-opioids and other adjuvants with the risk of developing complications, addictions and drug-seeking behaviour. Different non-pharmacological treatments, such as transcutaneous electrical nerve stimulation (TENS) have been used for managing pain in other painful conditions. Hence, the efficacy of TENS for managing pain in SCD needs to be reviewed. OBJECTIVES: To assess the benefits and harms of TENS for managing pain in people with SCD who experience pain crises or chronic pain (or both). SEARCH METHODS: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Haemoglobinopathies Register, comprising of references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings. We also searched online trial registries and the reference lists of relevant articles and reviews. Date of the last search: 26 Febraury 2020. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs, where TENS was evaluated for managing pain in people with SCD. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility of the trials identified by the literature searches according to the inclusion criteria. Two review authors then independently extracted data, assessed for risk of bias using the Cochrane standard tool and rated the quality of evidence using the GRADE guidelines. MAIN RESULTS: One double-blind cross-over RCT with 22 participants with SCD (aged 12 to 27 years) was eligible for inclusion. Following stratification into four pain crises severity grades, participants were then randomised to receive TENS or placebo (sham TENS). The trial was concluded after 60 treatment episodes (30 treatment episodes of each treatment group). There is a lack of clarity regarding the trial design and the analysis of the cross-over data. If a participant was allocated to TENS treatment for an episode of pain and subsequently returned with a further episode of a similar degree of pain, they would then receive the sham TENS treatment (cross-over design). For those experiencing a pain episode of a different severity, it is not clear whether they were re-randomised or given the alternate treatment. Reporting and analysis was based on the total number pain events and not on the number of participants. It is unclear how many participants were crossed over from the TENS group to the sham TENS group and vice versa. The trial had a high risk of bias regarding random sequence generation and allocation concealment; an unclear risk regarding the blinding of participants and personnel; and a low risk regarding the blinding of the outcome assessors and selective outcome reporting. The trial was small and of very low quality; furthermore, given the issue with trial design we were unable to quantitatively analyse the data. Therefore, we present only a narrative summary and caution is advised in interpreting the results. In relation to our pre-defined primary outcomes, the included trial did not report pain relief at two to four weeks post intervention. The trial authors reported that no difference was found in the changes in pain ratings (recorded at one hour and four hours post intervention) between the TENS and the placebo groups. In relation to our secondary outcomes, the analgesic usage during the trial also did not show any difference between groups. Given the quality of the evidence, we are uncertain whether TENS improves overall satisfaction as compared to sham TENS. The ability to cope with activities of daily living was not evaluated. Regarding adverse events, although one case of itching was reported in the TENS group, the site and nature of itching was not clearly stated; hence it cannot be clearly attributed to TENS. Also, two participants receiving \u27sham\u27 TENS reported a worsening of pain with the intervention. AUTHORS\u27 CONCLUSIONS: Since we have only included one small and very low-quality trial, with a high risk of bias across several domains, we are unable to conclude whether TENS is harmful or beneficial for managing pain in people with SCD. There is a need for a well-designed, adequately-powered, RCT to evaluate the role of TENS in managing pain in people with SCD

    Setup planning for machining

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    Professionals as well as researchers can benefit from this comprehensive introduction into the topic of setup planning, which reflects the latest state of research and gives hands-on examples. Starting with a brief but thorough introduction, this book explains the significance of setup planning in process planning and includes a reflection on its external constraints. Step-by-step the different phases of setup planning are outlined and traditional as well as modern approaches, such as fuzzy logic based setup planning, on the solution of setup planning problems are presented. Three detailed examples of applications provide a clear and accessible insight into the up-to-date techniques and various approaches in setup planning

    <span style="font-size:11.0pt;font-family: "Times New Roman";mso-fareast-font-family:"Times New Roman";mso-bidi-font-family: Mangal;mso-ansi-language:EN-GB;mso-fareast-language:EN-US;mso-bidi-language: HI" lang="EN-GB">Participation of endogenous circadian rhythm in photoperiodic time measurement during ovarian responses of the subtropical tree sparrow, <i style="mso-bidi-font-style:normal">Passer montanus</i></span>

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    496-503Resonance experiment was employed to investigate the mechanism of photoperiodic time measurement during initiation of ovarian growth and functions in the subtropical population of female tree sparrow (Passer montanus) at Shillong (Latitude 25°34´N, Longitude 91°53´E).<span style="mso-ansi-language: EN-US;mso-bidi-font-weight:bold" lang="EN-US"> Photosensitive birds were subjected to various resonance light dark cycles of different durations such as: 12-(6L:6D), 24-(6L:18D), 36-(6L:30D), 48-(6L:42D), 60-(6L:54D) and 72-(6L:66D) h along with a control group under long days (14L:10D) for 35 days. Birds, exposed to long days, exhibited ovarian growth confirming their photosensitivity at the beginning of the experiment. The birds experiencing resonance light/dark cycles of 12, 36 and 60 h responded well while those exposed to24, 48 and 72 h cycles did not. Serum levels of estradiol-17β ran almost parallel to changes in the follicular size. Further, histomorphometric analyses of ovaries of the birds subjected to various resonance light dark cycles revealed distinct correlation with the ovarian growth and the serum levels of estradiol-17β. No significant change in body weight was observed in the birds under any of the light regimes. The results are in agreement with the avian external coincidence model of photoperiodic time measurement and indicate that an endogenous circadian rhythm is involved during the initiation of the gonadal growth and functions in the female tree sparrow. </span

    A brief history of mechanical engineering

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    What is mechanical engineering? What a mechanical engineering does? How did the mechanical engineering change through ages? What is the future of mechanical engineering? This book answers these questions in a lucid manner. It also provides a brief chronological history of landmark events and answers questions such as: When was steam engine invented? Where was first CNC machine developed? When did the era of additive manufacturing start? When did the marriage of mechanical and electronics give birth to discipline of mechatronics? This book informs and create interest on mechanical engineering in the general public and particular in students. It also helps to sensitize the engineering fraternity about the historical aspects of engineering. At the same time, it provides a common sense knowledge of mechanical engineering in a handy manner

    Effect of FeNb on microstructure and mechanical properties of Al-Cu-Ni alloy

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    The present research work deals with the investigation of mechanical properties and microstructure evaluation by particulate reinforcement of ferroniobium (FeNb) into Al-5Cu-2Ni alloy. The two-step stir casting method was employed for the fabrication of the material. The metallography study was carried out with optical microscopy (OM), scanning electron microscopy (SEM) with energy-dispersive x-ray spectroscopy (EDS), and x-ray diffraction (XRD). The XRD peaks revealed the presence of the Fe _2 Nb phase and intermetallic compound phases of Al _2 Cu and Al _3 Ni _2 . However, the Fe _2 Nb phase is in the form of short sticks uniformly distributed around the intermetallic compound phases. Tensile strength, microhardness and impact strength were evaluated according to ASTM standards. The average tensile strength and Vickers microhardness of the Al-5Cu-2Ni matrix alloy were 179 MPa and 115 HV respectively. By adding 1%, 3% and 5% of FeNb particulate reinforcement into Al-5Cu-2Ni alloy, the tensile strength could be enhanced to 185, 193 and 207 MPa respectively. The corresponding microhardness values were 130, 132 and 151 HV, respectively. Thus, the addition of 5% ferroniobium particulate reinforcement material could significantly enhance the tensile strength and microhardness of the composites. Fractography revealed that fracture mode changes from ductile to brittle with the reinforcement of FeNb particles. The FeNb particles resist the dislocation movement of the intermetallic compound phases in the composites leading to micro-cracks and subsequent brittle fracture

    Ultrasonic-assisted machining processes: a review

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    Thermal resistance of two and three-layer fabric assemblies for extreme cold weather protective clothing

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    471-476Two (FA2) and three (FA3) layer fabric assemblies have been fabricated in different configurations using cloth shirting angola, pile acrylic fabric, non-woven polyester fabric (batting), coated nylon fabric and nappa leather for designing and development of multilayer clothing to provide protection in extreme cold weather. The configurations of FA2 are cloth shirting angola, PU coated nylon fabric; pile acrylic fabric, PU coated nylon fabric; cloth shirting angola, nappa leather; and acrylic pile fabric, nappa leather. On the other hand, the configurations of FA3 are cloth shirting angola, non-woven polyester fabric, PU coated nylon fabric; pile acrylic fabric, non-woven polyester fabric, PU coated nylon fabric; cloth shirting angola, non-woven polyester fabric, nappa leather; and pile acrylic fabric, non-woven polyester fabric, nappa leather. Thermal resistance of these multilayer clothing assemblies has been evaluated using high-resolution FLIR thermal imaging camera operating in 8-12μm waveband and PID controlled Acmas hot plate in natural convection mode. The maximum thermal resistance, offered by FA2 and FA3, are 5.59 and 6.24 tog respectively. Rational spatial configurations of FA2 and FA3 are as per the temperature of human body parts, and these may be used in designing and development of protective clothing for extreme cold weather
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