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Search Results: 1 - 10 of 8186 matches for " Pressure chamber "
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Differences in Root Growth and Permeability in the Grafted Combinations of Dutch Tomato Cultivars (Starbuck and Maxifort) and Japanese Cultivars (Reiyo, Receive, and Magnet)  [PDF]
Tomomi Kakita, Ayami Abe, Takashi Ikeda
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.616266
Abstract: Grafting is widely established in agriculture and provides practical advantages for vegetable production. We investigated physiological differences between the grafted combinations of Dutch (Starbuck and Maxifort) and Japanese (Reiyo, Receive and Magnet) tomato cultivars. Plants were grown hydroponically until the flowers on the first truss bloomed, and the following parameters were measured: fresh weight of the aerial parts, root surface area, root permeability (by using a pressure chamber), and water potential of exudates (by using an isopiestic psychrometer). The Starbuck/Maxifort combination had higher values of the aerial part weight, root surface area, and root permeability than Reiyo/Receive, whereas Reiyo/Maxifort tended to have higher values of these parameters than Reiyo/Receive and Reiyo/Magnet. Maxifort had a significantly larger root surface area than Receive, but root permeability was not significantly different. InReiyo/Maxifort and Starbuck/Receive, these parameters were not significantly different except for a single comparison of root permeability. Thus, root permeability and root surface area may depend not only on the rootstock but be also affected by scion in grafted plants. Water potential of exudates was similar in most combinations and experiments. This shows that three rootstock cultivars provided similar nutrient concentrations even with different scions.
The ‘full sleeve’ application in the horizontal cold-chamber machine for pressure die casting of aluminium alloys
Z. Konopka,A. Zyska,M. ??giewka,A. Bielecka
Archives of Foundry Engineering , 2008,
Abstract: The ‘full sleeve’ construction has been designed and accomplished in the horizontal cold-chamber pressure die casting machine. Main part of this solution is a counter plunger placed in a movable die half which allows for full filling of the shot sleeve and precisely fixes the metal quantity needed for casting. The purpose of this new construction solution is mainly the reduction of the casting porosity caused by air entrapment and the improvement of both castability and accuracy of the die cavity reproduction. For such a redesigned machine there have been performed examinations consisting in pressure casting of AlSi9Cu alloy (EN AC-46000) at varying plunger velocity in the second stage of injection and varying intensification pressure. The alloy castability (the die filling ability) has been measured for each parameter setting. For the purpose of comparison, similar measurements have been performed also for the conventional system without a counter plunger. The castability examination has been done by means of a specially designed die with an impression of a trial casting of variable wall thickness. The experiments have been held according to the assumed factor design 22, what allowed for determining the mathematical models describing the influence of die filling parameters on the castability and the die cavity reproduction level. Both alternatives of the experiment confirmed the positive influence of plunger velocity and intensification pressure increase on the improvement of castability, the measure of the latter being the filled length of the impression. Applying of the new ‘full sleeve’ solution has improved castability for each experiment by about 20% as compared with conventional alternative. Castability in the ‘full sleeve’ system has been increased even for low values of plunger velocity and intensification pressure. For both alternative systems the influence of plunger velocity has been found, as an average, by four times greater than the influence of intensification pressure. The possibility of applying lower pressure values has been noticed for the shot sleeve construction with the counter plunger. This can influence favourably both the die and the machine durability. The obtained results have been explained and it has been pointed out that the ‘full sleeve’ construction can be widely adopted in pressure die casting of metal alloys.
Comparación de la cámara de presión tipo Scholander modelo Pump-up respecto a la cámara de presión tradicional en vides de mesa
Gálvez Pavez,Rodrigo; Callejas Rodríguez,Rodrigo; Reginato Meza,Gabino;
Idesia (Arica) , 2011, DOI: 10.4067/S0718-34292011000200023
Abstract: abstract the aim of this study was to relate the stem water potential (ψxm) measurements obtained with the scholander type pressure chamber pump-up model (pms instrument company, oregon, usa) to those obtained with the traditional pressure chamber model 3005 (soil moisture, corp. santa barbara, ca, usa). the trial was conducted in two year old grapevines cultivar thompson seedless, in which three conditions of water status were generated; hydrated plants (c1), plants under drought stress (c2) and plants with an intermediate water status (c3), in order to obtain a wide range of ψxm. for each plant ψxmwas assessed at solar noon with the pump-up and the traditional pressure chamber models. the relationship between measurements of the pressure chambers fit a positive linear function with a slope close to 1 and with a high determination coefficient (r2 = 0.999, p-value < 0.001). this indicates no difference between the pressure chamber measurements.
Measurement of Sound Pressure Levels in Anechoic Chamber and a Noisy Environment Experimentally  [PDF]
Mohammad Al Zubi
Open Journal of Acoustics (OJA) , 2018, DOI: 10.4236/oja.2018.82002
Abstract: In real life, when a noise problem occurs, it is important to identify the cause and measure the noise of the source, since it may affect human beings or other constructions due to vibration generated from noise, so it is necessary to determine the noise related to a specific source like a machine in the presence of other sources which is a very important approach in noise control engineering. In this article a full experiment was executed to measure the sound pressure levels of various sources (stationary and non-stationary), in both an anechoic chamber and a non-ideal noisy environment. The sound pressure level was extracted for different sources and compared for both ideal and non-ideal environment. The results showed that acoustical free field of the space is the best field to do measurements to avoid reflection, on the other hand the difference between the source and the background should be more than 3 dB to get better results.
Fuga de triamcinolona intravítrea a cámara anterior
Blanco,C.; Fagúndez,A.; Buznego,L.; López-Moya,J.;
Archivos de la Sociedad Espa?ola de Oftalmología , 2007, DOI: 10.4321/S0365-66912007001200014
Abstract: case report: a 78-year-old man with phakic eyes underwent photodynamic therapy followed by intravitreal injection of triamcinolone. during the injection a white solution was observed in the anterior chamber. slit lamp examination revealed white opacities in the inferior anterior chamber angle and neither inflammatory activity nor corneal changes were noticed. discussion: intravitreal triamcinolone has been used for treating macular edema and various retinal vascular and inflammatory diseases. we describe the passage of triamcinolone to the anterior chamber during the injection in a phakic eye as a very unusual adverse effect, observed probably as a result of a zonular defect.
Pengembangan dan Aplikasi Prototipe Pendiferensial Tekanan untuk Deteksi Kebocoran pada Sistem Penumatik
Harus Laksana Guntur
Jurnal Teknik Mesin , 2009,
Abstract: In a pneumatic system, the differentiated value of pressure is often used for special objective. For instance, in process control of pressure the differentiated value of pressure is used as feedback. The mechanism used to obtain the differentiated value of pressure is called pressure differentiator. In this research, we developed a pressure differentiator by adding an isothermal chamber to minimize error caused by temperature fluctuations. The developed prototype was tested and the result show that the pressure differentiator with isothermal chamber in it has higher accuracy as compared with the one without isothermal chamber. The prototype was also applied to detect leak of a pneumatic piping system. The results show that the differentiated pressure increases as the leak size increases:-20Pa and -75Pa for leak size of 2x10-6m3/s and 3x10-6m3/s, respectively. The results also proved that the developed pressure differentiator is applicable for leak detection. Abstract in Bahasa Indonesia: Di dalam sistem penumatik nilai diferensial tekanan seringkali digunakan untuk tujuan tertentu, misalnya sebagai umpan balik pada proses pengendalian tekanan. Alat yang digunakan untuk mendapatkan nilai diferensial ini disebut pendiferensial tekanan (pressure differentiator). Pada penelitian ini dikembangkan sebuah prototipe pendiferensial tekanan dengan tambahan berupa ruang isotermal. Penambahan ini bertujuan untuk meminimalkan kesalahan pengukuran yang terjadi akibat fluktuasi temperatur yang disebabkan oleh perubahan tekanan pada objek ukur. Hasil pengujian prototipe menunjukkan bahwa pendiferensial tekanan dengan ruang isotermal memiliki akurasi yang lebih tinggi dibandingkan dengan pendiferensial tekanan dengan ruang biasa. Setelah diuji kemudian prototipe digunakan untuk mendeteksi kebocoran pipa udara. Hasil pendeteksian yang diperoleh menunjukkan bahwa nilai diferensial tekanan meningkat jika tingkat kebocoran bertambah, yaitu -20Pa dan -75Pa untuk tingkat kebocoran 2x10-6m3/s dan 3x10-6m3/s. Hal ini membuktikan bahwa pendiferensial tekanan juga bisa digunakan sebagai alat pendeteksi kebocoran udara. Kata kunci: Sistem penumatik, pendiferensial tekanan, ruang isothermal, deteksi kebocoran.
S. Zhylin,D. Volkov,L. Zhylina
Аvtomob?lnyi Transport , 2011,
Abstract: The program for unseparated combustion chamber parameters calculation is developed. The calculation investigation for parameters choice of VAZ-341 diesel engine combustion chamber at different rates of compression and fuel injection pressure is carried out.
Adaptation to periodic pressure chamber hypoxia and its influence on systolic and diastolic functions in chronic heart failure
Dmitrieva М.К.
Saratov Journal of Medical Scientific Research , 2012,
Abstract: Research objective is to determine the influence of adaptation method to periodic pressure chamber hypoxia on dynamics of systolic and diastolic functions of myocardium in patients with early stages of chronic heart failure. Materials and Methods: 100 men with post-infarction cardiosclerosis at the age of 40-65 years with I and IIA stages and l-ll functional classes (NYHA) of chronic heart failure have been examined. Results: Positive dynamics of systolic and diastolic cardiac functions and other parameters of echocardioscopy under the influence of the hypoxic therapy in comparison with classical physical rehabilitation have been obtained. Furthermore, a more significant effect has been observed in patients with CHF IIA. Conclusion: Improvement in the geometry of the heart has proved that adaptation method to periodic pressure chamber hypoxia could be recommended for rehabilitation of patients with heart failure of early stages.
Uso de la cámara de presión y los psicrómetros a termocupla en la determinación de las relaciones hídricas en tejidos vegetales
Phyton (Buenos Aires) , 2008,
Abstract: advantages, disadvantages and precautions of using the pressure chamber and thermocouple psychrometers for determinations of plant water potential, and osmotic and turgor pressures are discussed. comparison of results obtained with both instruments will be influenced by the sampling technique, consistency in both sampling and measurement procedures, and errors inherent to the method itself. in-situ readings of either plant or soil water potential with thermocouple psychrometers are perhaps worthless, or worse (they may even be misleading). use of thermocouple psychrometers is strictly limited to the laboratory where isothermal conditions can be obtained. the method to determine the water relations of plant tissues should be chosen according to the plant material and the research objectives.
Comparative biometric study between plateau iris configuration and primary open angle glaucoma with narrow angle
Diniz Filho, Alberto;Cronemberger, Sebasti?o;Mérula, Rafael Vidal;Calixto, Nassim;
Arquivos Brasileiros de Oftalmologia , 2009, DOI: 10.1590/S0004-27492009000300005
Abstract: purpose: to investigate biometrically the differences between plateau iris configuration (pic) eyes and primary open angle glaucoma with narrow angle eyes. methods: a comparative study involving a case series with 20 eyes of 11 plateau iris configuration patients and 45 eyes of 27 primary open angle glaucoma with narrow angle eyes patients was done. the following measurements were taken: corneal curvature, central corneal thickness, anterior chamber depth, lens thickness (lt), axial length (al), lens thickness and axial length ratio, lens position (lp) and relative lens position (rlp). results: the plateau iris configuration eyes presented a higher corneal cuvature value than primary open angle glaucoma with narrow angle eyes eyes but not with clinical and statistical difference (p=0.090). the plateau iris configuration eyes demonstrated a higher central corneal thickness, with statistical significance, when compared to primary open angle glaucoma with narrow angle eyes (p=0.010). statistical significant difference between plateau iris configuration and primary open angle glaucoma with narrow angle eyes was found in axial length (21.69 ± 0.98 vs. 22.42 ± 0.89; p=0.003). no significant difference was found when anterior chamber depth (2.62 ± 0.23 vs. 2.71 ± 0.31; p=0.078), lt (4.67 ± 0.36 vs. 4.69 ± 0.45; p=0.975), lt/al (2.16 ± 0.17 vs. 2.10 ± 0.21; p=0.569), lp (4.95 ± 0.25 vs. 5.06 ± 0.34; p=0.164) and rlp (0.23 ± 0.01 vs. 0.22 ± 0.14; p=0.348) were evaluated. conclusion: the eyes with plateau iris configuration presented statistical significantly shorter axial length and higher central corneal thickness than primary open angle glaucoma with narrow angle eyes.
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