541 research outputs found
Comparative Study of Load Carrying Capacity of Steel Tube Columns Filled with Lightweight Concrete and Normal Concrete
Tests on steel columns filled with normal concrete and lightweight concrete were carried out to investigate the actual behavior and the load carrying capacity of such columns. Eight full scale rectangular cross-section columns filled with lightweight aggregate concrete and normal weight aggregate concrete, four specimens each, were tested under axial loads for comparison purposes. The results showed that using lightweight concrete filling instead of normal concrete filling will reduce the weight of columns. At the same time, a high load carrying capacity is achieved
Optimizing the k-NN metric weights using differential evolution
Traditional k-NN classifier poses many limitations including that it does not take into account each class distribution, importance of each feature, contribution of each neighbor, and the number ofinstances for each class. A Differential evolution (DE) optimization technique is utilized to enhance the performance of k-NN through optimizing the metric weights of features, neighbors and classes. Several datasets are used to evaluate the performance of the proposed DE based metrics and to compare it to some k-NN variants from the literature. Practical experiments indicate that in most cases, incorporating DE in k-NN classification can provide more accurate performance. ©2010 IEEE
Dissolution of Gypseous Rocks under Different Circumstances
The influence of temperature, flow velocity, gypsum content, salinity of solvent and hole diameter on the amount and rate of dissolution of gypseous rock samples was investigated. The rock samples were obtained from the proposed Al-Fat’ha dam site located approximately 280km to the north of Baghdad city. The gypsum content for these samples ranged from 16% to 90%. Dissolution tests were carried out with the aid of a special system that was modified and manufactured to allow passing water at different speeds through a drilled hole along the center of the rock samples. The amount of dissolution of gypsum was determined under different conditions. The results showed that the amount and rate of gypsum dissolution increased with increasing the temperature of the test. The effect was more pronounced on rock samples with low gypsum content. Increasing the flow velocity also increases the amount and rate of gypsum dissolution. With this parameter, the effect of gypsum content was marginal. Increasing the salinity of the solvent (using low percentages of NaCl additives) has a great influence on the amount and rate of gypsum dissolution, and further increase in the salinity exhibited a marginal increase in the amount of dissolution when compared with the lower salinity concentration. The Tigris river water (as a natural solvent) exhibited a negligible effect on the amount and rate of gypsum dissolution. Increasing the diameter of the hole along the center of the sample increases the inside area exposed to water and hence generates more dissolution
Placental Morphology of Pregnant Iraqi Women with Rheumatic Heart Disease
Background: Placental morphology and cellular arrangement can be altered in maternal diseases. Rheumatic heart disease (RHD) is a chronic heart condition that can lead to death in pregnant women. The aim of this study is to determine the histological changes of the placenta in pregnant women suffering from RHD. Methods: Placentae were collected from 10 healthy pregnant women, and 31 pregnant women with heart conditions (26 with RHD and 5 with NRHD) who had been admitted to the Baghdad Teaching Hospital. Placental tissues were fixed in 10% formal-saline and were processed for light microscopy. Measurements including the placental weight and diameter of the chorionic villi capillaries were recorded. Results: The results indicate that there are many histological changes in pregnant women with RHD such as hyalinisation, fibrosis of the chorionic villi, proliferation of trophoblastic cells, and thickening of its membrane. Additionally, expectant mothers with RHD experience a reduction in capillary diameter and thickening of the capillary walls, and decreased size and weight of their placenta when compared with the control. Conclusions: Heart diseases, especially RHD, are associated with developmental damage of the placenta in pregnant women by injuring the endothelial cells of the placentas capillaries
Optimal Number of States in Hidden Markov Models and its Application to the Detection of Human Movement
In this paper, Hidden Markov Model is applied to model human movements as to facilitate an automatic detection of the same. A number of activities were simulated with the help of two persons. The four movements considered are walking, sitting down-getting up, fall while walking and fall while standing. The data is acquired using a biaxial accelerometer attached to the person’s body. Data of the four body gestures were then trained to construct several Hidden Markov models for the two people. The problem is to get a good representation of the data in terms of the number of states of the HMM. Standard general methods used for training pose some drawbacks i.e. the computational burden and initialisation process for the model estimate. For this reason, a sequential pruning strategy is implemented to address the problems mentioned.Keywords: Hidden Markov Models, sequential pruning strategy, Bayesian Inference Criterio
Stimulation of Hatching Efficiency in Capsulated Cysts of Artemia fransiscana Using 890 nm Diode Laser
Artemia fransiscana is one of the most important live food for commercial larval aquaculture.
The aim of this study is to investigate the effects of 890 nm diode laser irradiation on Artemia capsulated cysts using (1-10) minutes exposure time, and 2.26x10-3 J/cm2 Fluence. The Artemia samples were obtained from two locations: Dyalaa and Basraa. After irradiation, hatching percentage (H %) and hatching efficiency(HE) of Artemia were measured after 24 and 48 hours of incubation.
The results of the effect of laser light on the capsulated cysts from Dyalaa showed that the optimum dose for enhancing (H %) after 24 hours of incubation is using 10 minutes exposure time, while after 48 hours of incubation the (H %) enhancement can be achieved using 6 minutes exposure time. The optimum exposure times for (HE) enhancement after 24 and 48 hours of incubation were 5 and 7 minutes.
The results of the effect of laser light on the capsulated cysts from Basraa showed that after 24 hours of incubation, the optimum exposure times for enhancement (H%) was 9 minutes, while after 48 hours of irradiation the best exposure times was 5 minutes .
Very effective enhancement of (HE) was noticed after 24 hours of irradiation at 3 minutes exposure time using 2.26x10-3 J/cm2 Fluence. No enhancement was observed after 48 hours of irradiation
In conclusion, 890 nm diode laser irradiation can be used successfully for increasing Hatching percentage (H %) and Hatching Efficiency (HE) of Artemia capsulated cysts using certain energy density and certain exposure time
A Review of Literature of Initial Trust in E-Services: The Case of Internet Banking Services in Jordanian Context
Assessment of Natural Radionuclides in Powdered Milk Consumed in Iraq
The activity concentrations of 226Ra232Th, and 40K radionuclides were measured for 10 brands of powdered milk samples consumed in Iraq,which are imported from different countries.The main detected activity corresponding to 40K with average activity of 290.661 BqKg-1, while the average activities of 226Ra and232Th were below the detection level (B.D.L.).Results are compared with those of different countries worldwide.The total average annual effective doses due to intake of 40Kfrom the ingestion of the powdered milk for children (2-7, 7-12, 12-17)y and adults (≥ 17y) were estimated to be82.21, 50.90, 29.75 and 22.55 µSvy-1, respectively. These results indicate no significant radiation dose to the public. The resulting data may serve as base-line levels of activity concentration in powdered milk in the area of study. Keywords: Natural Radioactivity, Milk, Ingestion dose, Hazard quotient
The Diversity of Arbuscular Mycorrhizal Fungi in the Black Cumin Rhizosphere (Nigella sativa L.) in Cianjur, West Java, Indonesia
Arbuscular Mycorrhizal Fungi (AMF) is a type of fungus that can form a symbiotic mutualism with most plants. Some AMF can only be symbiotic with a certain plant species. This research aims to determine and obtain the genus AMF from black cumin (Nigella sativa L.) accessions from America, Turkey, Hong Kong, Slovenia, India, and Kuwait accessions which had been grown in West Java, Indonesia. Three samples from each accession, four replications each, were collected for examination. The results showed that six generas of AMF were found in the rhizosphere of black cumin: Glomus, Gigaspora, Acaulospora, Scutellospora, Dentiscutata, and Entrophospora. The genus Glomus was predominantly found in the Indian accession, i.e. 96.42 spores.Keywords: black cumin, diversity, fungi, exploration, AM
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