694 research outputs found
Response Transmissibility for Load Identification Improved By Optimal Sensor Locations
A knowledge of loads acting on a structure is important for analysis and design. There are many applications in which it is difficult to measure directly the dynamic loads acting on a component. In such situations, it may be possible to estimate the imposed loads through a measurement of the system output response. Load identification through output response measurement is an inverse problem that is not only ill-conditioned, but in general leads to multiple solutions. Therefore, additional information, such as number and locations of the imposed loads must be provided ahead of time in order to allow for a unique solution. This dissertation focuses on cases where such information is not readily accessible and presents a method for identification of loads applied to a structure using the concept of response transmissibility. The solution approach is divided into two phases that involve finding the number and location of forces first followed by a reconstruction of the load vector. To achieve the first phase, a complete description of the structure in terms of degrees of freedom needs to be specified and a numerical model, usually a finite element model is built. In order to determine the number of forces and their locations, the proposed algorithm combines the dynamic responses measured experimentally along with the transmissibility matrices obtained from the numerical model. Once the number of loads and their locations are known, a regeneration of the load vector is achieved during the second phase by combining the measured dynamic responses with the transmissibility matrix from the numerical model.
In this dissertation, identification of loads through measurement of structural response at a finite number of optimally selected locations is also investigated. Optimum sensor locations are identified using the D-optimal design algorithm. Two different types of measurements are considered, acceleration measurements using accelerometers and the strain measurements using strain gages.
A series of simulated results on multi-degree of freedom (MDOF) discrete and continuous systems are presented to illustrate the load identification technique based on response transmissibility. One of the factors that affects the accuracy of load reconstruction is the number of vibration modes included in the analysis, which can be a large number. Improvements using model order reduction, not only help reconstruct the input forces accurately, but it also reduces the computational burden significantly.
The developed algorithms are implemented using the finite element tool ANSYS in conjunction with MATLAB software. Numerical sensitivity analysis is also implemented to examine the effect of presence of uncertainties (noise) in experimental data. The results obtained confirm that the techniques presented are robust even in the presence of simulated noise; it is seen that the applied loads are recovered accurately
Protuupalno i analgetsko djelovanje novih derivata piridindikarbonitrila i benzopiranopiridina
In continuation of our search for new substituted pyridine based anti-inflammatories, reaction of 1-(2-thienyl or furanyl)-3-(2-hydroxyphenyl)-2-propen-1-ones (1) with malononitrile in alcoholic KOH solution afforded a mixture of 4-alkoxy-2-(2-thienyl or furanyl)-5H-[1]benzopyrano[3,4-c]pyridine-5-ones (2) and 2-alkoxy-4-amino-6-(2-thienyl or furanyl)-3,5-pyridinedicarbonitriles (3). Some of the synthesized compounds were evaluated for their anti-inflammatory and analgesic activities compared to diclofenac potassium as positive control. Detailed synthesis, spectroscopic and toxicity data are reported.U nastavku istraživanja derivata piridina s potencijalnim protuupalnim djelovanjem sintetizirani su 4-alkoksi-2-(2-tienil ili furanil)-5H-[1]benzopirano[3,4-c]piridin-5-oni (2) i 2-alkoksi-4-amino-6-(2-tienil ili furanil)-3,5-piridindikarbonitrili (3). Smjesa spojeva 2 i 3 dobivena je reakcijom 1-(2-tienil ili furanil)-3-(2-hidroksifenil)-2-propen-1-ona (1) s malononitrilom u alkoholnoj otopini KOH. Neki od sintetiziranih spojeva testirani su na protuupalno i analgetsko djelovanje, uz diklofenak kalij kao pozitivnu kontrolu. U radu su dani detaljni sintetski, spektroskopski i toksikološki podaci
Finite time stability of tempered fractional systems with time delays
We investigate the notion of finite time stability for tempered fractional
systems (TFSs) with time delays and variable coefficients. Then, we examine
some sufficient conditions that allow concluding the TFSs stability in a finite
time interval, which include the nonhomogeneous and the homogeneous delayed
cases. We present two different approaches. The first one is based on
H\"older's and Jensen's inequalities, while the second one concerns the
Bellman--Gr\"onwall method using the tempered Gr\"onwall inequality. Finally,
we provide two numerical examples to show the practicability of the developed
procedures.Comment: This is a preprint version of the paper published open access in
'Chaos Solitons Fractals
Preparation and Characterization of Nanocompocite Conducting Polymers (PANI-DBSA/MWNCT)
Nanocomposite conducting polymers ,PANI-DBSA/MWNCT were prepared by adding different weight ratios of c-MWNCT (1,2,3,5 ) % to Polyaniline (PANI) doped with DBSA( PANI-DBSA ). Structural characteristics of nanofibers composites and the formation of functional group were measured by . X-ray diffraction (XRD) and FT-IR spectroscopy. X-Ray Diffraction showed crystalline peaks of the Nanocomposites PANI-DBSA /MWNCT. FT-IR spectra confirmed the change of MWNCT to c-MWNCT by strong acids ,and PANI doped with DBSA. The Morphology and diameters for the nanofibers composites were studied by Atomic Force Microscope (AFM) and scanning electron microscope(SEM). The average diameter for nanofiber composites was about 117 nm (at 1 wt% MWCNT concentration ) and 90.47 nm (at 5wt% MWCNT concentration) found from AFM. SEM also show the homogeneous coating of PANI-DBSA onto the MWNCNT indicating that carbon nanotubes were well dispersed in conducting polymer matrix Keywords: conducting polymer, polyaniline, multi-walled carbon nanotubes, nanocomposites
Speeded Up Robust Features Descriptor for Iris Recognition Systems
اكتسبت النظم البايومترية اهتماما كبيرا لعدة تطبيقات. كان تحديد القزحية أحد أكثر التقنيات البايومترية تطوراً للمصادقة الفعالة. نظام التعرف على القزحية الحالية يقدم نتائج دقيقة وموثوق بها على أساس الصور المأخوذة بالأشعة التحت الحمراء (NIR) عندما يتم التقاط الصور في مسافة ثابتة مع تعاون المستخدم. ولكن بالنسبة لصور العين الملونة التي تم الحصول عليها تحت الطول الموجي المرئي (VW) دون التعاون بين المستخدمين، فإن كفاءة التعرف على القزحية تتأثر بسبب الضوضاء مثل صور عدم وضوح العين، و تداخل الرموش ، والانسداد بالأجفان وغيرها. يهدف هذا العمل إلى استخدام (SURF) لاسترداد خصائص القزحية في كل من صور قزحية NIR والطيف المرئي. يتم استخدام هذا النهج وتقييمه على قواعد بيانات CASIA v1and IITD v1 كصورة قزحية NIR وUBIRIS v1 كصورة ملونة. وأظهرت النتائج معدل دقة عالية (98.1 ٪) على CASIA v1, (98.2) على IITD v1 و (83٪) على UBIRIS v1 تقييمها بالمقارنة مع الأساليب الأخرى.Biometric systems have gained significant attention for several applications. Iris identification was one of the most sophisticated biometrical techniques for effective and confident authentication. Current iris identification system offers accurate and reliable results based on near- infra -red light (NIR) images when images are taken in a restricted area with fixed-distance user cooperation. However, for the color eye images obtained under visible wavelength (VW) without cooperation between the users, the efficiency of iris recognition degrades because of noise such as eye blurring images, eye lashing, occlusion and reflection. This works aims to use Speeded up robust features Descriptor (SURF) to retrieve the iris's characteristics in both NIR iris images and visible spectrum. This approach is used and evaluated on the CASIA v1and IITD v1 databases as NIR iris image and UBIRIS v1 as color image. The evaluation results showed a high accuracy rate 98.1 % on CASIA v1, 98.2 on IITD v1 and 83% on UBIRIS v1 evaluated by comparing to the other method
Anticancer Activities of Meroterpenoids Isolated from the Brown Alga Cystoseira usneoides against the Human Colon Cancer Cells HT-29
Colorectal cancer (CRC) is one of the most common types of cancers and a leading cause of cancer death worldwide. The current treatment for CRC mainly involves surgery, radiotherapy, and chemotherapy. However, due to the side effects and the emergence of drug resistance, the search for new anticancer agents, pharmacologically safe and effective, is needed. In the present study, we have investigated the anticancer effects of eight algal meroterpenoids (AMTs, 1-8) isolated from the brown seaweed Cystoseira usneoides and their underlying mechanisms of action using HT-29, a highly metastatic human colon cancer cell line. All the tested meroterpenoids inhibited the growth of HT-29 malignant cells and were less toxic towards non-cancer colon cells, with the AMTs 1 and 5 exhibiting selectivity indexes of 5.26 and 5.23, respectively. Treatment of HT-29 cells with the AMTs 1, 2, 3, 4, 5, and 7 induced cell cycle arrest in G2/M phase and, in some instances, apoptosis (compounds 2, 3, and 5). Compounds 1-8 also exhibited significant inhibitory effects on the migration and/or invasion of colon cancer cells. Mechanistic analysis demonstrated that the AMTs 1, 2, 5, 6, 7, and 8 reduced phosphorylation levels of extracellular signal-regulated kinase (ERK) and the AMTs 2, 3, 4, 5, 7, and 8 decreased phosphorylation of c-JUN N-terminal kinase (JNK). Moreover, the AMTs 1, 2, 3, 4, 7, and 8 inhibited phosphorylation levels of protein kinase B (AKT) in colon carcinoma cells. These results provide new insights into the mechanisms and functions of the meroterpenoids of C. usneoides, which exhibit an anticancer effect on HT-29 colon cancer cells by inducing cell cycle arrest and apoptosis via the downregulation of ERK/JNK/AKT signaling pathways
Nano composites of PAM Reinforced with Al2O3
الهدف من هذا البحث هو تحديد مدى تأثير نسب الوزن المختلفة لجسيمات الألومينا النانوية بنسب وزنية مختلفة تشمل 0.02 ، 0.04، و 0.06 في المائة نسبة وزنية على الخصائص الفيزيائية لبولي أكريلاميد (PAAM) . تم استخدام جهاز الخلاط المغناطيسي الحراري للحصول على المحاليل من إذابة 10 غم من مسحوق بولي أكريلاميد في 90 غم من الماء المقطر المؤين لمدة 4 ساعات لإنتاج محلول PAAM بتركيز 0.11 غم / مل . تم تقسيم المحلول الناتج الى أربعة أقسام متساوية من المحلول ، كل منها بحجم 20 مل. تمت إضافة دقائق الالومينا النانوية لكل محلول بشكل مستقل بنسب مختلفة 0.0 ، 0.02 ، 0.04 ، 0.06 لتكوين أربعة محاليل نانوية سائلة بمحتويات مختلفة من جسيمات الألومينا النانوية بناءً على كل نسبة وزن. تم استخدام عملية الصب اليدوي لعينات المركبات النانوية ، والتي تضمنت صب المحلول المحضر في قالب من البلاستيك بحجم مناسب وتركت المحاليل لمدة 24 ساعة لاتمام عملية التصلب لإنشاء أغشية النانو المركبة ، ثم قطع الغشاء الرقيق الناتج وفقًا لكل اختبار ،. تم استخدام اختبار الشد لدراسة قوة الشد ، ومعامل يونك ، والاستطالة ، والمتانة. بالإضافة إلى ذلك ، تم إجراء اختبار الأشعة تحت الحمراء (FTIR) لفحص الروابط الكيميائية والفيزيائية بين بولي أكريلاميد وجسيمات الألومينا النانوية. تم فحص مورفولوجيا السطح باستخدام جهاز المجهر الالكتروني الماسح. تم اختبار زوايا الترطيب للعينات لتحديد السلوك اتجاه الماء لهذه العينات.. أظهرت النتائج أن اضافة جسيمات الألومينا النانوية الى البولي اكريل امايد يحسن الخصائص الميكانيكية للمركبات النانوية الناتجة. تزداد قوة الشد من 1 كيكا باسكال إلى 2.5 كيكا باسكال مع زيادة محتوى الألومينا النانوية من 0 إلى 0.06٪ نسبة وزنية .و بالنسبة لنفس النسب السابقة ، زاد معامل يونك كذلك ، حيث ارتفع من 1.3 إلى 2 كيكا باسكال للنسبة الوزنية لجسيمات الألومينا النانوية 0.04 بالمائة بالوزن ، ترتفع المتانة إلى 240 جول / سم 2. من ناحية أخرى ، أدت إضافة دقائق الألومينا النانوية إلى زيادة زاوية التبلل لسطح PAAM من 55 درجة إلى 67 درجة ، وأظهرت سلوكًا محبًا للماء . The aim of this investigation is to determine how different weight percentages of alumina nanoparticles, including 0.02, 0.04, and 0.06 percent wt, affect the physical characteristics of Poly Acrylamide (PAAM). Using a hot plate magnetic stirrer, 10 g of poly acrylamide powder was dissolved in 90 g of di-ionized distillate water for 4 hours to produce PAAM with a concentration of 0.11 g/ml. Four sections of the resulting solution, each with a volume of 20 ml, were created. Each solution was added independently with alumina nanoparticles in different ratios 0.0, 0.02, 0.04, and 0.06 to create four nano fluid solutions with different alumina nanoparticle contents based on each weight percent. The hand casting process for nanocomposites samples, which entailed pouring the prepared solution into an appropriate plastic mold, allowing it to cure for 24 hours, and then cutting the resulting thin film according to each test, was used to create the nano composited membranes. The tensile test was used to study tensile strength, Young's modulus, elongation, and toughness. Additionally, a test using Fourier transition infrared radiation (FTIR) was conducted to examine the chemical and physical connections between polyacrylamide and alumina nanoparticles. The morphology of the materials was examined using scan electron microscopy. The contact angles of samples were tested to limit the hydrophilicity behavior of these samples. To control the hydrophilicity behavior of these samples, the contact angles of the samples were evaluated. The results showed that including alumina nanoparticles into the PAAM matrix improves the mechanical characteristics of the resulting nanocomposites. Tensile strength increases from 1 GPa to 2.5 GPa with an increase in alumina nanoparticle content from 0 to 0.06 percent wt. For the same prior ratios, Young's modulus likewise increased, rising from 1.3 to 2 GPa. For the higher weight ratio of alumina nanoparticles (0.04 percent wt), toughness rises to 240 J/cm2. On the other hand, the addition of alumina nanoparticles increased the PAAM surface's contact angle from 55 degrees to 67 degrees, and it exhibited hydrophilic behavio
VHDL Based Maximum Power Point Tracking of Photovoltaic Using Fuzzy Logic Control
It is important to have an efficient maximum power point tracking (MPPT) technique to increase the photovoltaic (PV) generation system output efficiency. This paper presents a design of MPPT techniques for PV module to increase its efficiency. Perturb and Observe method (P&O), incremental conductance method (IC), and Fuzzy logic controller (FLC) techniques are designed to be used for MPPT. Also FLC is built using MATLAB/ SIMULINK and compared with the FLC toolbox existed in the MATLAB library. FLC does not need knowledge of the exact model of the system so it is easy to implement. A comparison between different techniques shows the effectiveness of the fuzzy logic controller techniques. Finally, the proposed FLC is built in very high speed integrated circuit description language (VHDL). The simulation results obtained with ISE Design Suite 14.6 software show a satisfactory performance with a good agreement compared to obtained values from MATLAB/SIMULINK. The good tracking efficiency and rapid response to environmental parameters changes are adopted by the simulation results
Physical Behavior of a.PP/LDPE Blends under Different Conditions
يهدف البحث الى تصنيع خليط بوليميري من البولي بروبلين العشوائي مضافا اليه البولي اثيلين الواطئ الكثافه لغرض تصنيع منتج اقتصادي وكذلك تحسين الخواص الميكانيكيه عند درجه بثق (180 o C) الخواص الميكانيكيه. (الكثافه، مقاومه الشد، الاستطاله عند الكسر، مقاومه الصدمه، مقاومه الانحناء، ومعامل المرونه
تم تحضير اربعه نماذج من خلائط بوليميريه من (البولي بروبلين: بولي اثيلين واطئ الكثافه) بنسب وزنيه (10/90, 20:80, 30:70, &50:50) بدرجه بثق (180 o C).
حيث تم ملاحظه ان السلوك الميكانيكي للخليط يعتمد على مكوناته وكذلك درجه البثق. اثبتت النتائج ان مقاومة الصدمه ومعامل الانحناء تزداد بزيادة النسبه الوزنيه للبولي اثيلين الواطئ الكثافه واعلى قيمه كانت عند نسبه وزنيه (50:50).
بينما اعلى قيمه لمعامل المرونه كانت عند النسبه (30:70) كما اثبتت النتائج ان درجه البثق تؤثر كثيرا في السلوك الميكانيكي للخليط حيث تعمل على تحويل السلوك من المطاطي الى السلوك الهش الجاسئ مما يؤثر على نتائج الخواص الميكانيكيه بشكل كبير.كما اثبتت نتائج التحليل الحراري بجهاز المسعر الحراري التفاضلي زياده درجات التبلور للخليط بزياده نسبه البولي اثيلين الواطئ الكثافه كما تشير الى زياده درجه حراره التفكك الحراري للخليط مما يزيد من المقاومه الحراريه الخليط .اما نتائج الانسياب الحراري فقد اثبتت نقصان معامل الانسياب للنموذج بزياده محتوى البولي اثيلين % 30الى %50The aim of this work was to make LDPE /a.PP blends for economically attractive by (10/90, 20:80, 30:70, &50:50 w/w) ratios via injection molding carried out under 180 o C injection temperatures and to evaluate their mechanical properties including :( Density, Tensile Strength, Elongate to Break, Impact Strength, Bending Modulus,& Young's Modulus . we notice that the blend behavior dependent on its composition, and injection temperature .
Results show there are an increasing of impact strength and bending modulus with increasing of (LDPE) contain and the highest value of these properties were at (50:50) weight ratio, while it has the highest Young's modulus at (30:70) wt%. 180 o C as injection temperature leads to translate the mechanical behavior from ductile to stiff behavior. DSC curves show that the blends is immiscibility , also thermal degradation was decreased with increasing of LDPE to (50%).Also the Melt flow index decreased from (5.04)-(4.01) (g/10 min) with increasing of LDPE from (30%) to (50%)
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