Traditional tree management is laborious and costly, thus this work aimed to study the performance of two different types of frond cutting saws (reciprocating saw and vibrating saw) and examine the two saws on five date palm varieties. Four parameters were examined, including cutting time for a single frond, the power needed for cutting a single frond, frond cutting productivity expressed as tree/h, and vibration conveyed to the worker’s hand. A field experiment was designed according to the nested randomized complete block design, including five date palm varieties as the main plot and the type of saw as a sub-plot. Means were compared using the least significant differences (LSD 0.05). Results indicated that Bream variety required the least time for frond cutting. The reciprocating saw exhibited efficiency in saving the time required for frond cutting, while the vibrating saw took significantly longer time needed for cutting a single frond. The highest number of fronds cut in one hour was recorded in Bream variety, again significantly higher than the number of other studied varieties. Moreover, the reciprocating saw achieved significantly higher productivity than the vibrating one, indicating that the productivity of the reciprocating saw is almost three times more than the vibrating saw. Maximum productivity was recorded in Bream variety, while the least was recorded in Tebarzal using the vibrating saw. Moreover, results indicate that the variety and the type of saw have a vital role in productivity since as the thickness of a frond increases, the cutting takes more time and ultimately reduces the number of date palms to be pruned per hour. Results also exhibited that vibrating saw reduced the consumed energy during frond cutting. Additionally, results revealed that the minimum power consumed by a vibrating saw was in Bream variety, while Tebarzal consumed the upmost energy when a reciprocating saw was used. Maximum vibration on X-axis was reported in Bream variety when a vibrating saw was used. Additionally, the reciprocating saw exhibited the highest vibration compared with the vibrating saw. Moreover, the reciprocating saw caused the lowest vibration in Tebarzal variety. Results indicated that the vibration imposed by both saws reached the maximum value in Bream variety. The vibrating saw resulted in the higher vibration toward Z axis, while the Reciprocating saw resulted in higher vibration toward X axis, which was more than eight times that recorded by the vibrating saw. Results indicate that vibration toward the Y axis increased significantly in Bream variety compared with others. Again, as in the situation with X and Z axis, the reciprocating saw exhibited the highest vibration compared to that resulted from using a vibrating saw which was more than three times the vibration caused by the vibrating saw.
No-fine concrete (NFC) is cellular concrete and it’s light weight concrete produced with the exclusion of sand from the concrete. This study includes the mechanical properties of lightweight reinforced by steel fiber, containing different proportions of steel fiber. This study was done using number of tests. These tests were density, compressive strength, flexural strength and absorption. These tests of the molds at different curing time. The results of tests that implication of fiber to No. fine concrete did not affect significantly on the compressive strength, While the flexural strength were gets better. Results explained that, the flexural strength of (1%) fiber No- fine concrete molds are four times that of the reference mold
... Show MoreThree different distribution modules of silicon solar cells in a panel are used in this study . Each module consists of five identical circular silicon solar cells of radius (5cm) and then the total panel areas are identical. The five solar cells are arranged in the panel in different shapes: circular, triangular and rectangular .The efficiency for these three panel distribution are measured indoor and outdoor. The results show that the efficiency is a function of the cells distribution.
أستهدفت الدراسة اختبار أثر التوجه السوقي والتزام العاملين على أداء المنظمة المسوقة لخدمات النقل الجوي. حيث تم اختيار شركة الخطوط الجوية الملكية الأردنية كمجال تطبيقي.وقد اعتمدت الدراسة في قياس المتغيرات على مقاييس مختبرة وقد تأكد صحتها وثباتها لقياس المتغيرات في البيئة الحالية. وقد بينت نتائج التحليل الإحصائي الذي استخدمت فيه أساليب إحصائية مختلفة بالاستعانة ببرنامج SPSS))
In this work, a flat-plate solar air heater (FSAH) and a tubular solar air heater (TSAH) were designed and tested numerically. The work investigates the effect of increasing the contact area between the flowing air and the absorber surface of each heater and predicts the expected results before the fabrication of the experimental rig. Three-dimensional two models were designed and simulated by the ANSYS-FLUENT 16 Program. The solar irradiation and ambient air temperature were measured experimentally on December 1st 2022, at the weather conditions of Baghdad City- Iraq, at three air mass flow rates, 0.012 kg/s, 0.032 kg/s, and 0.052 kg/s. The numerical results showed the advantage in the thermal performance of
... Show MoreDuring the last quarter century, many changes have taken place in the tanks industry and also in the materials that used in its production، while concrete is the most suitable material where concrete tanks has the benefits of strength, long service life and cost effectiveness. So, it is necessary improvement the
conventional concrete in order to adapt the severe environment requirements and as a result high
performance concrete (HPC) was used. It is not fundamentally different from the concrete used in the past, although it usually contains fly ash, ground granulated blast furnace slag and silica fume, as well as
superplasticizer. So, the content of cementitious material is high and the water/cement ratio is low. In this
stu
Background: Ejection fraction have been used frequently
for assessment of the left ventricular function, but can be
associated with errors in which myocardial performance
index have been used as another parameter to measure the
left ventricular function.
Objective: selecting another echocardiography parameter
for the assessment of myocardial in function instead of the
ejection fraction.
Methods: 160 patients referred to the echocardiogram unit
from the period december 2007 to august 2008 requesting
assessment of left ventricular function. After clinical
examination, routine blood tests; chest x-ray and
electrocardiographic recording have been completed. All
patients informed to come for this unit af
Despite widespread agreement on the beneficial nature of hydrated lime (HL) addition to asphalt concrete mixes, understanding of the effect of HL particle size is still limited. Previous investigations have focused mainly on two different size comparisons, and so certain guidance for a practical application cannot yet be produced. This study investigates three distinct sizes of HL, in the range of regular, nano, and sub-nano scales, for their effects on the properties of modified asphalt concretes. Five different percentages of HL as a partial replacement of ordinary limestone filler in asphalt concrete mixes were studied for wearing course application purposes. Experimental tests were conducted to evaluate the mechanical properties
... Show MoreRecently, interest in the use of projectiles in research on recycling waste materials for construction applications has grown. Using recycled materials for the construction of asphalt concrete pavement, in the meantime, has become a topic of research due to its significant benefits, such as cost savings and reduced environmental impacts. This study reports on comprehensive experimental research conducted using a typical mechanical milling waste, iron filing waste (IFW), as an alternative fine aggregate for warm mix asphalt (WMA) for pavement wearing surface applications. A type of IFW from a local machine workshop was used to replace the conventional fine aggregate, fine natural sand (FNS), at percentages of 25%, 50% 75%, and 100% b
... Show MoreThe pharmacokinetics and bioequivalence of a newly developed extended-released (ER) tablet containing 400 mg pentoxifylline as a test product was compared with the reference brand product Trental® 400 mg ER tablet produced by Sanofi-Aventis. Two separate studies were conducted simultaneously. The first study was conducted under fasting condition, whereas, the second study was conducted under fed condition; using the same batches of the test and reference products in both studies. In each study, both products were administered to 32 healthy male adult volunteers applying a single-dose, two-treatment, two-period, two-sequence, randomized crossover design with one-week washout period between dosing. Twenty two blood samples we
... Show More
Background: Repeated blood transfusion is the main therapeutic option for transfusion-dependent anaemias with consequent iron overload and organ damage .Therefore iron chelating agents are important protective measures for these patients. The aim of this study was to investigate the efficiency and safety of Desferroxamine in paediatrics population subjected to iron overload as a consequence of repeated transfusion in a group of Sudanese children Subjects & Methods: This was a descriptive cross-sectional hospital based study. Conducted in two main paediatric reference hospitals in, Su |