252 research outputs found
Finite Element Thermal Analysis of Conformal Cooling Channels in Injection Moulding
The process cycle time in injection moulding process depends greatly on the cooling time of the plastic part, which is facilitated by the cooling channels in the injection mould. Effective cooling channel design in the mould is important because it not only affects cycle time but also the part quality. Traditional cooling channels are normally made of straight drilled holes in the mould, which have limitations in geometric complexity as well as cooling fluid mobility within the injectio n mould. Over the years, conformal cooling techniques are being introduced as effective alternative to conventional cooling. The main objective of this study is to determine an optimum design for conformal cooling channel of an injection moulded plastic part using finite element analysis and thermal heat transfer analysis. The part cooling time is optimized by conformal cooling channels in the mould using the ANSYS thermal a nalysis software. Analysis of virtual models showed that those with conformal cooling channels predicted a significant reduction of cycle time with expected improvement in part quality
Improved Anticancer Effect of Magnetite Nanocomposite Formulation of GALLIC Acid (Fe₃O₄-PEG-GA) Against Lung, Breast and Colon Cancer Cells
Lung cancer, breast cancer and colorectal cancer are the most prevalent fatal types of cancers globally. Gallic acid (3,4,5-trihydroxybenzoic acid) is a bioactive compound found in plants and foods, such as white tea, witch hazel and it has been reported to possess anticancer, antioxidant and anti-inflammatory properties. In this study we have redesigned our previously reported anticancer nanocomposite formulation with improved drug loading based on iron oxide magnetite nanoparticles coated with polyethylene glycol and loaded with anticancer drug gallic acid (Fe₃O₄-PEG-GA). The in vitro release profile and percentage drug loading were found to be better than our previously reported formulation. The anticancer activity of pure gallic acid (GA), empty carrier (Fe₃O₄-PEG) nanocarrier and of anticancer nanocomposite (Fe₃O₄-PEG-GA) were screened against human lung cancer cells (A549), human breast cancer cells (MCF-7), human colon cancer cells (HT-29) and normal fibroblast cells (3T3) after incubation of 24, 48 and 72 h using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) MTT assay. The designed formulation (Fe₃O₄-PEG-GA) showed better anticancer activity than free gallic acid (GA). The results of the in vitro studies are highly encouraging to conduct the in vivo studies
Circadian Organization in Hemimetabolous Insects
The circadian system of hemimetabolous insects is reviewed in respect to the locus of the circadian clock and multioscillatory organization. Because of relatively easy access to the nervous system, the neuronal organization of the clock system in hemimetabolous insects has been studied, yielding identification of the compound eye as the major photoreceptor for entrainment and the optic lobe for the circadian clock locus. The clock site within the optic lobe is inconsistent among reported species; in cockroaches the lobula was previously thought to be a most likely clock locus but accessory medulla is recently stressed to be a clock center, while more distal part of the optic lobe including the lamina and the outer medulla area for the cricket. Identification of the clock cells needs further critical studies. Although each optic lobe clock seems functionally identical, in respect to photic entrainment and generation of the rhythm, the bilaterally paired clocks form a functional unit. They interact to produce a stable time structure within individual insects by exchanging photic and temporal information through neural pathways, in which
serotonin and pigment-dispersing factor (PDF) are involved as chemical messengers. The mutual interaction also plays an important role in seasonal adaptation of the rhythm
Sustained release of anticancer agent phytic acid from its chitosan-coated magnetic nanoparticles for drug-delivery system
Chitosan (CS) iron oxide magnetic nanoparticles (MNPs) were coated with phytic acid (PTA) to form phytic acid-chitosan-iron oxide nanocomposite (PTA-CS-MNP). The obtained nanocomposite and nanocarrier were characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometry, transmission electron microscopy, and thermogravimetric and differential thermogravimetric analyses. Fourier transform infrared spectra and thermal analysis of MNPs and PTA-CS-MNP nanocomposite confirmed the binding of CS on the surface of MNPs and the loading of PTA in the PTA-CS-MNP nanocomposite. The coating process enhanced the thermal stability of the anticancer nanocomposite obtained. X-ray diffraction results showed that the MNPs and PTA-CS-MNP nanocomposite are pure magnetite. Drug loading was estimated using ultraviolet-visible spectroscopy and showing a 12.9% in the designed nanocomposite. Magnetization curves demonstrated that the synthesized MNPs and nanocomposite were superparamagnetic with saturation magnetizations of 53.25 emu/g and 42.15 emu/g, respectively. The release study showed that around 86% and 93% of PTA from PTA-CS-MNP nanocomposite could be released within 127 and 56 hours by a phosphate buffer solution at pH 7.4 and 4.8, respectively, in a sustained manner and governed by pseudo-second order kinetic model. The cytotoxicity of the compounds on HT-29 colon cancer cells was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The HT-29 cell line was more sensitive against PTA-CS-MNP nanocomposite than PTA alone. No cytotoxic effect was observed on normal cells (3T3 fibroblast cells). This result indicates that PTA-CS-MNP nanocomposite can inhibit the proliferation of colon cancer cells without causing any harm to normal cell
Thermodynamic Geometry Of Charged Rotating BTZ Black Holes
We study the thermodynamics and the thermodynamic geometries of charged
rotating BTZ (CR-BTZ) black holes in (2+1)-gravity. We investigate the
thermodynamics of these systems within the context of the Weinhold and
Ruppeiner thermodynamic geometries and the recently developed formalism of
geometrothermodynamics (GTD). Considering the behavior of the heat capacity and
the Hawking temperature, we show that Weinhold and Ruppeiner geometries cannot
describe completely the thermodynamics of these black holes and of their
limiting case of vanishing electric charge. In contrast, the Legendre
invariance imposed on the metric in GTD allows one to describe the CR-BTZ black
holes and their limiting cases in a consistent and invariant manner
Thermodynamics of charged and rotating black strings
We study thermodynamics of cylindrically symmetric black holes. Uncharged as
well as charged and rotating objects have been discussed. We derive surface
gravity and hence the Hawking temperature and entropy for all these cases. We
correct some results in the literature and present new ones. It is seen that
thermodynamically these black configurations behave differently from
spherically symmetric objects
Tunnelling Methods and Hawking's radiation: achievements and prospects
The aim of this work is to review the tunnelling method as an alternative
description of the quantum radiation from black holes and cosmological
horizons. The method is first formulated and discussed for the case of
stationary black holes, then a foundation is provided in terms of analytic
continuation throughout complex space-time. The two principal implementations
of the tunnelling approach, which are the null geodesic method and the
Hamilton-Jacobi method, are shown to be equivalent in the stationary case. The
Hamilton-Jacobi method is then extended to cover spherically symmetric
dynamical black holes, cosmological horizons and naked singularities. Prospects
and achievements are discussed in the conclusions.Comment: Topical Review commissioned and accepted for publication by
"Classical and Quantum Gravity". 101 pages; 6 figure
Capturing Tacit Knowledge in oil and gas project Using Storytelling
Knowledge plays a vital role in managing project. Generally, knowledge is being
categorized into two: explicit and tacit. Tacit knowledge is the .Icnow - how"
knowledge that lies in expert's head, while explicit knowledge is wriuen and
codified knowledge. Both are long term assets to ev€ry project and putting effort to
nurture them is very critical. Though so, most projects are having ditrculty in
sharing tacit knowledge because of its nature that preve,lrted the knowledge from
being articulated and formalized. Therefore, integrating knowledge mnnagEneNf
into project enables tacit knowledge to be captured, codified, and then shared across
the project. One ofthe best ways in sharing tacit knowledge is using storytelling. As
part of knowledge management, storytelling offers sharing of a more strucmred and
absorbable form of tacit knowledge. This paper shares a viewpoint of knowledge
sharing in oil and gas project since the indusry embraces lots oftechnical skills ad
experience based learning. Besides, this paper pres€Nrts the research methodology
which begins with planning until the development process
“Ovo je trebalo biti smiješno – zašto se ne smijete!” – izvođenje povijesti i turističke šetnje u Budimpešti (Sažetak)
The turn to performativity in the social sciences has spawned a new wave of scholarship that considers tourism as a performative process. However, the manner through which scholars understand tourism as performative drama is limiting. A fundamental critique of dramaturgy stems from its inability to account for performance as a chain of emergent social processes. Using the case of free walking tours in Budapest, Hungary, we argue that treating tourism as a performance is an act of fusion that culls its technique by deploying dominant cultural codes, materiality and humor. Performance hinges on an attempt to fuse various elements in a dramatic presentation. These elements include the (1) unsettling presence of the audience’s feedback, (2) the lingering memory of previous performances, (3) the deployment of cultural codes, (4) the mundanity of the material means of symbolic presentation, and (5) the use of linguistic play through humor. We conclude this essay by elaborating other dimensions that could possibly open up more discussions on tourism as a performative phenomenon.Performativni obrat u društvenim znanostima obuhvatio je i studije o turizmu koji se u tom kontekstu promatra kao izvedbeni process. Dosadašnje studije ukazuju na određena ograničenja ovoga pristupa. Fundamentalna kritika dramaturškog pogleda jest da izvedbenost ne promatra kao niz pojavnih društvenih procesa. Na primjeru besplatnih turističkih šetnji (free walking tours) u Budimpešti, u članku se analizira turizam kao izvedbeni čin koji se realizira kombiniranjem dominantnih kulturnih kodova, upotrebom predmeta te humorom. Realiziran je kao pokušaj spajanja različitih elemenata u dramaturšku prezentaciju. U članku se raspravlja slijedećih pet elemenata izvedbe turističkih vodiča- njihova interakcija sa publikom/turistima, prethodna iskustva, upotreba kulturnih kodova, svakodnevica predmeta čije se simbolika koristi u prezentaciji te poigravanje sa jezičnim formama kroz humor. U zaključku predlažemo nekoliko dimenzija koje se mogu uključiti u daljnja promišljanja i rasprave o turizmu kao izvedbenom fenomenu
Levels of Glucose-6-phosphate Dehydrogenase in Type 1 Diabetes Mellitus patients with Nephropathy and Cardiovascular disease complication
The aim of this study is to evaluate oxidative stress in diabetes mellitus (DM) Type1 by the measurement of Glucose-6-phosphate Dehydrogenase (G-6-PD), an enzyme expressed in human RBCs, is important in the generation of reduced glutathione which is the key product in oxidative stress controls. The Study was carried on 80 samples of blood and serum of National Diabetes Center (NDC). The study groups under fasting conditions and they divided as:20 samples of diabetes mellitus patients without complications and 20 samples of diabetes mellitus with cardiovascular (CV) complications and 20 samples of diabetes mellitus with Nephropathy (Neph) complications compared with 20 control group with average age (13-67) years.. The results showed an elevation in the lipid profile and urea levels in patients groups compared with control group and a decrease in glucose-6-phosphate Dehydrogenase, HDL levels in all patients groups compared with control group
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