39 research outputs found

    Thermal analysis of SUS 304 stainless steel using ethylene glycol/nanocellulose-based nanofluid coolant

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    Green cooling system usage in machining is getting favors to minimize the environmental effect such as pollutions. Around 20% of the machining cost is about coolant usage in flooded cooling technique. Even though coolant has a reasonably low cost, their handling and disposing cost are very high and also, threatening toxic contents, disposal of used coolant is a big problem as it can lead to hazardous effect to the machining operates as well as to the environment. As an alternative, a cooling technique known as minimum quantity lubrication (MQL) was introduced in the machining operation. For MQL technique, the coolant should exhibit superior properties which are effective in machining operation when compared with the conventional machining coolant which is metal working fluid (MWF). Owing to the technology advancements by nanotechnology in nanomaterial, the nanofluid is a promising coolant that can replace the conventional machining coolant. In the present work, ethylene glycol/nanocellulose-based nanofluid is evaluated in terms of its thermo-physical properties and its effectiveness in machining performances which is temperature distribution in cutting tool and compare its effectiveness with MWF. Its effectiveness is tested in turning machining operation of SUS 304 stainless steel using cemented tungsten-cobalt (WC-Co)-coated carbide cutting insert. The turning operation by using ethylene glycol/nanocellulose-based nanofluid coolant with 0.5 vol% which exhibit a superior thermal conductivity of 0.449 W/m K than 0.267 W/m K thermal conductivity of MWF at 30 °C. The recorded lower amount of heat transfer to the cutting tool is 863 J compared with 1130 J when using MWF. On the other hand, the maximum temperature reading recorded at chip formed by using MWF is 225 °C whereas by using nanofluid is 154 °C which promises lower temperature distribution to chip formed during the machining operation. Also, the functionality of nanofluid as a thermal transport during machining is proven via chip formation observation analysis and scanning electron microscope (SEM) with energy-dispersive X-ray (EDX) spectrum analysis

    Working Toward Human-Centered, Reparative Change Through Print Collection Development at the University of Denver

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    In 2014, the DU Libraries began to address a lack of work by and about the Cheyenne and Arapaho people in its collections, and moved toward reparative change in response to historical traumas suffered by Indigenous Peoples. The history of this work and its origins—which led to the creation of the Libraries’ Collection Diversification Task Force (CDTF) and now informs the Libraries’ collection development philosophy and operational inclusivity—are discussed in the “Developments Leading to the Collection Diversification Task Force” section of this chapter. Further on, the “Collection Diversification Task Force” section clarifies methodology, recommendations, and self-discovery on the part of librarians. Finally, “Reflections for Future Work” summarizes where collection diversification currently stands at DU Libraries and highlights the role of administrative support in encouraging this process to continue

    Study of pufferfish (Takifugu niphobles) sperm: development of methods for short-term storage, effects of different activation media and role of intracellular changes in Ca2+ and K+ in the initiation of sperm motility

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    [EN] The first goal of this study was the development of a short-term storage method for pufferfish (Takifugu niphobles) sperm. In this respect, the best results were obtained by diluting the sperm in a seminal-like solution and keeping it in a Petri dish in chilled storage (4 degrees C). This method was successful in preserving sperm quality parameters without resulting in differences in fresh sperm for a relatively long-term period (7 days), for use in aquaculture matters. The addition of bovine serum albumin (BSA) to the medium did not improve the results. On the other hand, both the osmolality and the ion composition of the media are essential factors which can modulate the sperm motility parameters. The osmolality of the activating medium was the most important factor in triggering pufferfish sperm motility, and osmolalities of 750-825 mOsm/kg were necessary to initiate this process, demonstrating that it appears to be a dose-independent mechanism. Regarding the ion composition of the activation media, this study has shown that despite the spermatozoa being able to initiate movement without any ion in the activation medium, the absence of ions can negatively affect the kinetic parameters of the spermatozoa. Finally, in natural conditions (seawater), the activation of sperm motility generates intracellular increases in Ca2+ and K+, suggesting that these ions play an essential role in the activation mechanism of pufferfish sperm. (C) 2013 Elsevier B.V. All rights reserved.This study was funded by the Spanish Ministry of Science and Innovation (MICINN; AGL2010-16009). Victor Gallego has a predoctoral grant (MICINN; BES-2009-020310) and has been granted a fellowship (EEBB-I-12-05858) from the Spanish Personnel Research Training Programme to carry out this study in the Misaki Marine Biological Station (Miura, Japan).Gallego Albiach, V.; PĂ©rez Igualada, LM.; Asturiano Nemesio, JF.; Yoshida, M. (2013). Study of pufferfish (Takifugu niphobles) sperm: development of methods for short-term storage, effects of different activation media and role of intracellular changes in Ca2+ and K+ in the initiation of sperm motility. Aquaculture. 414:82-91. https://doi.org/10.1016/j.aquaculture.2013.07.046S829141

    Reduced neural synchronization of gamma-band MEG oscillations in first-degree relatives of children with autism

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    <p>Abstract</p> <p>Background</p> <p>Gamma-band oscillations recorded from human electrophysiological recordings, which may be associated with perceptual binding and neuronal connectivity, have been shown to be altered in people with autism. Transient auditory gamma-band responses, however, have not yet been investigated in autism or in the first-degree relatives of persons with the autism.</p> <p>Methods</p> <p>We measured transient evoked and induced magnetic gamma-band power and inter-trial phase-locking consistency in the magnetoencephalographic recordings of 16 parents of children with autism, 11 adults with autism and 16 control participants. Source space projection was used to separate left and right hemisphere transient gamma-band measures of power and phase-locking.</p> <p>Results</p> <p>Induced gamma-power at 40 Hz was significantly higher in the parent and autism groups than in controls, while evoked gamma-band power was reduced compared to controls. The phase-locking factor, a measure of phase consistency of neuronal responses with external stimuli, was significantly lower in the subjects with autism and the autism parent group, potentially explaining the difference between the evoked and induced power results.</p> <p>Conclusion</p> <p>These findings, especially in first degree relatives, suggest that gamma-band phase consistency and changes in induced versus induced power may be potentially useful endophenotypes for autism, particularly given emerging molecular mechanisms concerning the generation of gamma-band signals.</p

    Research into the effect Of SGLT2 inhibition on left ventricular remodelling in patients with heart failure and diabetes mellitus (REFORM) trial rationale and design

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    Background Heart failure (HF) and diabetes (DM) are a lethal combination. The current armamentarium of anti-diabetic agents has been shown to be less efficacious and sometimes even harmful in diabetic patients with concomitant cardiovascular disease, especially HF. Sodium glucose linked co-transporter type 2 (SGLT2) inhibitors are a new class of anti-diabetic agent that has shown potentially beneficial cardiovascular effects such as pre-load and after load reduction through osmotic diuresis, blood pressure reduction, reduced arterial stiffness and weight loss. This has been supported by the recently published EMPA-REG trial which showed a striking 38 and 35 % reduction in cardiovascular death and HF hospitalisation respectively. Methods The REFORM trial is a novel, phase IV randomised, double blind, placebo controlled clinical trial that has been ongoing since March 2015. It is designed specifically to test the safety and efficacy of the SLGT2 inhibitor, dapagliflozin, on diabetic patients with known HF. We utilise cardiac-MRI, cardio-pulmonary exercise testing, body composition analysis and other tests to quantify the cardiovascular and systemic effects of dapagliflozin 10 mg once daily against standard of care over a 1 year observation period. The primary outcome is to detect the change in left ventricular (LV) end systolic and LV end diastolic volumes. The secondary outcome measures include LV ejection fraction, LV mass index, exercise tolerance, fluid status, quality of life measures and others. Conclusions This trial will be able to determine if SGLT2 inhibitor therapy produces potentially beneficial effects in patients with DM and HF, thereby replacing current medications as the drug of choice when treating patients with both DM and HF

    Paradoxical Effects of Rapamycin on Experimental House Dust Mite-Induced Asthma

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    The mammalian target of rapamycin (mTOR) modulates immune responses and cellular proliferation. The objective of this study was to assess whether inhibition of mTOR with rapamycin modifies disease severity in two experimental murine models of house dust mite (HDM)-induced asthma. In an induction model, rapamycin was administered to BALB/c mice coincident with nasal HDM challenges for 3 weeks. In a treatment model, nasal HDM challenges were performed for 6 weeks and rapamycin treatment was administered during weeks 4 through 6. In the induction model, rapamycin significantly attenuated airway inflammation, airway hyperreactivity (AHR) and goblet cell hyperplasia. In contrast, treatment of established HDM-induced asthma with rapamycin exacerbated AHR and airway inflammation, whereas goblet cell hyperplasia was not modified. Phosphorylation of the S6 ribosomal protein, which is downstream of mTORC1, was increased after 3 weeks, but not 6 weeks of HDM-challenge. Rapamycin reduced S6 phosphorylation in HDM-challenged mice in both the induction and treatment models. Thus, the paradoxical effects of rapamycin on asthma severity paralleled the activation of mTOR signaling. Lastly, mediastinal lymph node re-stimulation experiments showed that treatment of rapamycin-naive T cells with ex vivo rapamycin decreased antigen-specific Th2 cytokine production, whereas prior exposure to in vivo rapamycin rendered T cells refractory to the suppressive effects of ex vivo rapamycin. We conclude that rapamycin had paradoxical effects on the pathogenesis of experimental HDM-induced asthma. Thus, consistent with the context-dependent effects of rapamycin on inflammation, the timing of mTOR inhibition may be an important determinant of efficacy and toxicity in HDM-induced asthma

    Titanium Oxide with Nanocoolant for Heat Exchanger Application

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    The objective of this paper is to investigate the properties of oil-based nanofluids and produce stable and biodegradable oil-based nanofluids by metal oxide nanoparticles. The cooking oil was used as a base for the nanofluid preparation. Titanium oxide was embedded as the nanoparticles, mixed with cooking oil volume concentration of nanofluids specimens, and labelled as 0.01, 0.03, 0.05, 0.07, and 0.09. The study explained the analysis techniques applied to determine the enhancement of thermal properties of nanofluids. The thermal conductivity of nanofluids was studied by heat transfer rate and the overall heat transfer coefficient gained. The metal oxide nanomaterials were mixed with the oil-based fluids in order to prepare the specimens. This research focused on the usage of vegetable oil and titanium oxide nanoparticles mixture to form nanofluids. The results obtained indicated that the nanofluid gave better thermal conductivity than oil-based fluids. The results significantly increased the thermal properties limitation and improved the product reliability. The enhancement of heat transfer rate for 0.09% of nanofluid volume concentration was increased by 36.25
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