On the propagation of a periodic flame front by an arrhenius kinetic

We consider the propagation of a flame front in a solid medium with a periodic structure. The model is governed by a free boundary system for the pair" temperature-front. "The front's normal velocity depends on the temperature via a (degenerate) Arrhenius kinetic. It also depends on the front's mean curvature. We show the existence of travelling wave solutions for the full system and consider their homogenization as the period tends to zero. We analyze the curvature effects on the homogenization and obtain a continuum of limiting waves parametrized by the limiting ratio "curvature coefficient/period." This analysis provides valuable information on the heterogeneous propagation as well.Comment: 42 pages. The statements of Theorems 7 and 8 have been improve

Faktor-Faktor Yang Mempengaruhi Produksi Dan Pendapatan Usahatani Jeruk Keprok Soe Di Kabupaten Timor Tengah Selatan

Factors Affecting The Production and Revenue Of Keprok Soe Citrus Farming in Timor Tengah Selatan. The aim of this study is to analyse the factors influence the production and income of the Keprok SoE Citrus farming. The location is purposively defined in North Mollo Subdistrict as a citrus production central. Two villages are choosen (Ajaobaki and Fatukoto) because they are the bigger producers of Keprok SoE Citrus farming. 50 farmers are choosen as the respondents. The data are collected by doing some interviews. Cobb-Douglass production function is employed to analyse the factors influencing the production and income. As the results of the production analysis, the age of the plants has impact to the production with negative sign, whereas labor, harvested area, use of fertilizer, experience of the farmers and dummy variables of education have impacts to the production with positive signs. The age of the farmers, price of the seeds, price of the Californian porridge, wage and dummy of education have negatively sign impacts to the farmers' income

Quelques remarques sur les solutions bornées des équations stationnaires d'Hamilton-Jacobi

International audienceWe study here the equation $H(Du) = H(0), x \in \mathbb{R} ^N$. More precisely we investigate under which hypotheses the constant functions are the only bounded solutions. In arbitrary space dimension we prove that this happens when strict convexity and coercivity occur. In one space dimension we show that the above property holds true for hamiltonians in a larger class. These results apply when studying the long time behaviour of solutions for time-dependent Hamilton-Jacobi equations.Dans cette note on s’intéresse à l’équation $H(Du) = H(0), x \in \mathbb{R} ^N$ et plus précisément à la question suivante : dans quels cas les fonctions constantes sont-elles les seules solutions bornées de cette équation ? On démontre que tel est le cas sous des hypothèses de stricte convexité et coercivité en dimension N quelconque. La preuve fait appel à la formule de Hopf-Lax. En une dimension d’espace on propose un résultat pour des hamiltoniens seulement faiblement coercifs moyennant une condition supplémentaire. Dans la dernière partie on utilise ces résultats pour identifier les limites asymptotiques en temps long des solutions des problèmes de Cauchy

A characterization of the solutions of steady Hamilton-Jacobi equations

In this note, we propose to revisit the approximate stationary Hamilton-Jacobi equations and analyse the corresponding solutions following certain properties of the hamiltonian. This enables us to give a characterization of the zero set of the limiting solution. We also remark that the analysis can be applied for evolution equations with a time periodic source term

Acrylic Composite Biomaterials for Dental Applications: A Review of Recent Progress

Polymethyl methacrylate (PMMA) is regarded as one of the most widely used and prominent biomaterials for biomedical applications, particularly in dental technology. The unique properties of PMMA regarding its aesthetics, price-affordable availability, easy manipulation, low density, and tailorable mechanical behaviours, make it an eminently suitable biomaterial for such applications. Despite its beneficial properties, PMMA has also some shortcomings in terms of susceptibility to hydrolytic degradation and having insufficient mechanical properties that could prevent this material to be able to handle the various applied forces during its use, which in turn make it vulnerable to fracture. Furthermore, PMMA could serve as a substrate to growth of harmful bacteria and fungi such as Candida glabrata that can cause agents of oral cavity infection and could seriously affect the stamina and person’s health in general. A wide range of approaches have been developed in order to enhance not only the mechanical and thermal behaviours but also water sorption, solubility and the biological activities of PMMA. Incorporating of reinforcement additives into PMMA matrix can improve these properties of PMMA. Several methods and materials have been utilised to reinforce acrylic resin denture base. One of these methods is the reinforcement by using particles whether from natural or synthetic sources including metals and ceramics. Apart from their sources, the particles surface characteristics, quantity and level of dispersion play an essential role in overall behaviour of the composites. Other types of reinforcements are natural and human-made fibers. Each of such has merits and disadvantages; while the synthetic fibers can provide better mechanical properties, natural fibers promote creating better composites in terms of biocompatibility and affordability. Nanotubes are the other spectacular kind of materials being utilised in some studies as a reinforcing phase for PMMA composites. This review will highlight the recent studies that have been conducted for the last decade regarding the development of PMMA-based composite biomaterials for dental applications

Kadar Tanin, Kalsium (Ca), dan Fosfor (P) Tepung Kulit Pisang Fermentasi dengan Cairan Rumen Kambing

ABSTRAK Kulit pisang merupakan hasil samping pengolahan makanan yang dapat digunakan sebagai pakan ternak. Kadar tanin yang tinggi pada kulit pisang membatasi penggunaannya sebagai pakan monogastrik. Kandungan tanin dalam bahan pakan dapat dikurangi dengan teknologi fermentasi. Mikroorganisme yang berperan dalam proses fermentasi dapat diperoleh dari cairan rumen hewan ruminansia seperti kambing. Tujuan penelitian untuk mengetahui pengaruh kadar cairan rumen kambing terhadap kadar tanin, kalsium (Ca), dan fosfor (P) tepung kulit pisang kepok. Rancangan acak lengkap dengan empat perlakuan dan lima ulangan digunakan dalam penelitian ini. Perlakuannya adalah R0: tepung kulit pisang kepok + cairan rumen 0% (kontrol), R1: tepung kulit pisang kepok + cairan rumen 30%, R2: tepung kulit pisang kepok + cairan rumen 40%, R3: tepung kulit pisang kepok + 50 % cairan rumen. Proses fermentasi dilakukan selama 7 hari. Hasil penelitian menunjukkan bahwa kadar cairan rumen kambing memiliki kandungan tanin dan kalsium yang lebih rendah secara nyata (P0,05) terhadap kadar fosfor pada tepung kulit pisang. Disimpulkan bahwa penggunaan cairan rumen kambing hingga 40% dapat menurunkan kandungan tanin dan kalsium pada tepung kulit pisang.Kata kunci: cairan rumen, fermentasi, tepung kulit pisang kepokTannin, Calcium (Ca), and Phosphorus (P)Content of Banana Peel Flour Fermented by Goat Rumen FluABSTRACTBanana peel is a food processing by-product that can be used as animal feed. High tannin levels of banana peels restrict its use as monogastric animals feed. The tannin content of feed ingredients can be reduced by fermentation technology. Microorganisms that play a role in the fermentation process can be obtained from the rumen fluid of ruminants like a goat. The objective of this research was to determine the effect of goat rumen fluid levels on the content of tannins, calcium (Ca), and phosphorus (P) of Kepok banana peel flour. A completely randomized design with four treatments and five replicates was used in this study. The treatments were R0: banana peel flour + 0% rumen fluid (control), R1: banana peel flour + 30% rumen fluid, R2: banana peel flour + 40% rumen fluid, R3: banana peel flour + 50% rumen fluid. The fermentation process was carried out for 7 days. The results showed that goat rumen fluid levels had significantly (P0.05) on phosphorus level in banana peel flour. In conclusion, the use of goat rumen fluid up to 40 % can reduce the content of tannins and calcium of banana peel flour.Keywords: rumen fluid, fermentation, kepok banana peel flou

Echocardiographic Findings in Patients with Chronic Obstructive Pulmonary Disease and Their Correlation with Disease Severity

الخلفية: مرض الانسداد الرئوي المزمن هو مرض شائع وله تأثيرات كبيرة على وظائف القلب، بما في ذلك من البطين الأيمن، البطين الايسر، والأوعية الدموية الرئوية وان معظم الزيادة في الوفيات المرتبطة بمرض الانسداد الرئوي المزمن ناتجة عن مضاعفات الاصابة القلبية. يوفر تخطيط صدى القلب طريقة سريعة، سهلة التنقل,غير باضعة، ودقيقة لتقييم التغيرات الحاصلة في القلب. هدف الدراسة: تقييم التغيرات القلبية الناتجة عن مرض الانسداد الرئوي المزمن عن طريق تخطيط صدى القلب ومعرفة ما إذا كان هناك ارتباط بين نتائج تخطيط صدى القلب وشدة مرض الانسداد الرئوي المزمن طريقة البحث: تم اختيار مجموعة مؤلفة من 50 مريض تم تشخيص اصابتهم بمرض الانسداد الرئوي المزمن و تقسيمهم الى أربعة مراحل وفقا لمعايير المبادرة العالمية لمرض الانسداد الرئوي المزمن.لجميع المرضى تم اخذ التاريخ الطبي المفصل وإجراء فحص سريري دقيق مع عمل تخطيط القلب الكهربائي ,تصوير الصدر بالاشعة السينية ,واختبارات الدم الروتينية.كافة المرضى تم تقييمهم بواسطة تخطيط صدى القلب النتائج: أظهر تقييم المرضى بواسطة تخطيط صدى القلب ان 40٪ من الحالات التي تمت دراستها كانت تحمل معطيات طبيعية .وقد لوحظ قلس الصمام ثلاثي الشرف القابل للقياس في 25/50 (50.0٪) من الحالات. ارتفاع ضغط الدم الرئوي والذي يعرف بانه ارتفاع ضغط دم الشريان الرئوي الانقباضي أكثر من 30ملم زئبق لوحظ في 14\25 (56,0%) من المرضى الذين وجد عندهم قلس الصمام ثلاثي الشرف  (28% من عدد المرضى الكلي في الدراسة) وقد توزعت شدة المرض(ارتفاع ضغط الدم الرئوي) كالاتي :7\14(50,0%) خفيف ,4\14(28,6%) معتدل ,3\14(21,4%) شديد.كما أظهرت الدراسة أن وتيرة ارتفاع ضغط الدم الرئوي بالنسبة لكل من مراحل مرض الانسداد الرئوي المزمن الخفيف ,المعتدل ,الشديد ,و الشديد جدا كان كالاتي:7,1% ,14,3% ,35,7% ,42,9% على التعاقب. أظهرت الدراسة وجود مرض القلب الرئوي في 6\14(42,9%) من الحالات (12% من العدد الكلي للمرضى في الدراسة) كما لوحظ ان وتيرة مرض القلب الرئوي بالنسبة لحالات ارتفاع ضغط الدم الرئوي الخفيف ,المعتدل ,والشديد , كان :صفر ,75% ,100% ,على التوالي.كما لوحظ  اعتلال البطين الايسر الانقباضي في 2% من الحالات ,اعتلال البطين الايسر الانبساطي في 10% ,وتضخم البطين الايسر في 4% من الحالات.كما وجد ان هنالك انخفاض كبير في معدل حجم الزفير القسري في ثانية واحدة بالتزامن مع التغييرات المكتشفة بواسطة تخطيط صدى القلب (بالاخص ارتفاع ضغط الدم الرئوي ومرض القلب الرئوي). الاستنتاج: ان معدل انتشار مضاعفات القلب والاوعية الدموية (وخاصة ارتفاع ضغط الدم الرئوي ومرض القلب الرئوي) عند المصابين بمرض الانسداد الرئوي المزمن عال وله علاقة خطية مع زيادة شدة المرض. تخطيط صدى القلب يساعد في الكشف المبكر عن المضاعفات القلبية عند مرضى الانسداد الرئوي المزمن معطيا بذلك الوقت للتدخل المبكرBackground : Chronic obstructive pulmonary disease (COPD) is a common  disease and has remarkable effects on cardiac functions, including those of the right ventricle, left ventricle, and pulmonary blood vessels. Most of the increased mortality associated with COPD is due to cardiac involvement. Echocardiography(Echo) provides a rapid, noninvasive, portable, and accurate method to evaluate the cardiac changes. Aim of study: To assess cardiac changes secondary to COPD by echocardiography and to find if there is a correlation between echocardiographic findings and severity of COPD. Materials and Methods:A total 50 of patients with COPD were diagnosed and staged by pulmonary function test (PFT) according to GOLD criteria into 4 stages . For all patients,detailed history, carful clinical examination, electrocardiography(ECG), chest x ray(CXR), and routine blood tests were done. All patients evaluated by echocardiography. Results: On echocardiographic evaluation of COPD,40% of  cases had normal echocardiographic parameters. Measurable tricuspid regurgitation (TR) was observed in 25/50 (50.0%) of cases . Pulmonary hypertension (PHT), which is defined as systolic pulmonary arterial pressure (sPAP)> 30 mmHg was observed in 14/25 (56.0%) of patients with TR (28.0% of total patients) , in which prevalence of mild, moderate, and severe PHT were 7/14 (50.0%), 4/14 (28.6%), and 3/14 (21.4%), respectively. The frequencies of PHT in mild, moderate, severe, and very severe COPD were 7.1%, 14.3 %, 35.7%, and 42.9%, respectively. Cor pulmonale was observed in 6/14 (42.9%) of cases (12.0% of total patients) ; The frequencies of cor pulmonale  in  patients with  mild, moderate, and sever PHT were 0 , 75.0% ,100.0 % ,respectively ; 2.0% cases had left ventricle systolic dysfunction(LVSD) and 10.0% cases had evidence of left ventricle diastolic dysfunction(LVDD). Left ventricle hypertrophy (LVH) was found in 4.0% of cases. Conclusion: Prevalence of cardiovascular complications (especially PHT and cor pulmonale) is high among COPD patients and has a linear relationship with increasing severity of COPD. Echocardiography helps in early detection of cardiac complications in COPD cases giving time for early interventions

Characterization of the speed of a two-phase interface in a porous medium

A typical situation of oil reservoir simulation is considered in a porous medium where the resident oil is displaced by water injection. An explicit expression of the speed of the oil-water interface is given in a pseudo-2D case via the resolution of an auxiliary Riemann problem. The explicit 2D solution is then corroborated with numerical simulations by solving the transport equation with a generalized scheme of Harten type