Evaluating a ZigBee Network with SMC for Hard and Concurrent Parameter Variations

One of the main issues concerning a wireless networked control system is the variable delay associated with the communicating network used to join its dispersed components.  This paper presents a variable structured Sliding Mode Controller (SMC) designed for a ZigBee wireless networked control system (WNCS) in addition to the design of a standard PID controller. WNCS can improve the reliability and the effectiveness of the control system by eliminating time and costs of installation and maintenance. Presence of time delays between sensors, actuators and controllers of the controlled system can degrade the performance and destabilize the whole system. To reduce the effect of the network delay, simulation tools for WNCS are developed to help designers in studying the influence of network on performance of the control system. The TrueTime toolbox is used to analyze the effects of network delays and to evaluate the effects of ZigBee parameters on control systems such as packet loss, ACK. Timeout limit, and traffic load. It is clear from the results that SMC is superior to PID control. Keywords: NCS, SMC, PID, ZigBee, TrueTim

Pattern, First Aid and Complications of Snake Bite in Sudan

Aim: This study aimed at assessing the first aid management and types of complications arising from snakebite. Patients and methods:  A survey of snakebites cases admitted to Sinnar Teaching Hospital, Sinnar, Sudan was conducted between March 2011 and March 2013. The demographic and clinical details of each case were obtained using a questionnaire design to collect primary data from patients and their relatives and patient’s, while, secondary data was collected from the hospital record. Data was analyzed using frequency tabulation. Results: A total number of 111 cases of snake bites were reported during the period of study. The most common age group affected was 19-36 years. The highest number of incidents occurred during daytime from July to December, and lower limb was the major affected part of the body. 41.1% of the victims were farmers. Tourniquet was found to be the most commonly used first aid.  The major observed complications were cellulitis and spontaneous bleeding.  A mortality rate of 3.6% was reported. Conclusion: Extensive use of tourniquet as a first aid measure is one of the primary causes of complications from snakebite. Correct first aid and scientifically based medical intervention are very important snakebite management mechanism and can reduce its complications considerably. Aim: This study aimed at assessing the first aid management and types of complications arising from snakebite. Patients and methods:  A survey of snakebites cases admitted to Sinnar Teaching Hospital, Sinnar, Sudan was conducted between March 2011 and March 2013. The demographic and clinical details of each case were obtained using a questionnaire design to collect primary data from patients and their relatives and patient’s, while, secondary data was collected from the hospital record. Data was analyzed using frequency tabulation. Results: A total number of 111 cases of snake bites were reported during the period of study. The most common age group affected was 19-36 years. The highest number of incidents occurred during daytime from July to December, and lower limb was the major affected part of the body. 41.1% of the victims were farmers. Tourniquet was found to be the most commonly used first aid.  The major observed complications were cellulitis and spontaneous bleeding.  A mortality rate of 3.6% was reported. Conclusion: Extensive use of tourniquet as a first aid measure is one of the primary causes of complications from snakebite. Correct first aid and scientifically based medical intervention are very important snakebite management mechanism and can reduce its complications considerably

Derivation of Bearing Capacity Equation for a Two Layered System of Weak Clay Layer Overlaid by Dense Sand Layer

Calculation of the ultimate bearing capacity of shallow footing on a two layered system of soil depends on the pattern of the failure surface that develops below the footing. For a weak clay layer overlaid by a top dense sand layer, previous studies assumed that the failure surface is a punching shear failure through the upper sand layer and Prandtl's failure mode in the bottom weak clay layer. By adapting this assumption in this study, the ultimate bearing capacity equation was derived as a function of the properties of soils, the footing width, and the topsoil thickness. The paper presents a detailed parametric study of the design parameters including the effect of angle of friction, the ratio of the thickness of sand layer to the footing width, the ratio of the depth of embedment to the footing width, and the ratio of the clay soil cohesion to the product of the clay unit weight by the footing width. Design charts were developed in dimensionless form for very wide ranges of design parameters. The available method based on the limit equalibrium analysis was developed in dimensionlised form and for a limited range of design parametrs. The new charts give another option for those who believe that the design charts developed based on the upper limit analysis overestimate the bearing capacity due to the very nature of the upper bound solution. The new design charts are limited to shallow footings

Encuesta de expectativas de inflación

Banco de la República tiene como objetivo principal el control de la inflación. Las expectativas de los agentes juegan un papel primordial en el logro de las metas de política económica, entre ellas la reducción de la inflación. Por lo anterior, el Banco de la República realiza un seguimiento de las expectativas de los agentes mediante una encuesta de opinión. A continuación se presentan las principales características de la encuesta del Banco de la República y algunos de sus resultados en casi dos años de existencia

Antibacterial Activities of Yansoon (Pimpinella anisum L.), Ginger (Zingiber officinale L.) and Cinnamon (Cinnamomum zeylanicum L.) Extracts

There is an increasing demand for the biologically active substances from plant origin which is of current interest and focus for new research approach. The synthetic pharmaceuticals compounds showed various side effects on functions of different parts of the human body, both internally and externally. Therefore, the present study was investigating the antimicrobial activity of three important herbs, Ginger (Zingiber officinale L.), Yansoon (Pimpinella anisum L.) and Cinnamon (Cinnamomum zeylanicum L.). The cup- plate agar (inhibition zone) method was used for studying the effects of the extracts against Streptococcus sp, Staphylococcus aureus and  Enterococcus faecalis. The results showed that, the ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Streptococcus sp (24mm and 21mm, respectively), compared to the water extracts (15mm and16mm, respectively). However, the water and the ethanol extracts of ginger and yansoon were less effective (11mm, 9mm, 8.5mm and 8mm, respectively). The ethanol extracts of cinnamon and the combination of ginger and cinnamon were highly effective on Staphylococcus aureus giving (24mm and 21.5 mm, respectively) followed by water extract (20mm and 21 mm, respectively). While, the ethanol and water extracts of ginger and yansoon were less effective (11mm, 10.5mm, 9mm and 9.5mm, respectively). The ethanol and water extracts of cinnamon were highly effective on E. faecalis giving (21mm and 20.5 mm, respectively). The ethanol extracts of the combination of ginger and cinnamon were effective (20 mm) followed by water extract (18mm). The water and ethanol extracts of ginger and yansoon were less effective giving (15 mm, 12 mm, 8 mm and 9 mm, respectively). From the results it could be concluded that, the extracts of (Cinnamon, Yansoon and Ginger) can be used as antimicrobial agents. It could be suggested that the active antimicrobial components need to be verified in any further study and more microorganism are to be tested                                                                                          . &nbsp

Physicochemical Analysis of the Drinking Water of Al Gedarif City, Sudan

In the present study the highest residual chlorine level (0.2) was detected in the city inlet and the circular line of the Atbara River sources. The taste, color and odor were found acceptable, although, the ground water is a bit salty and the raw water of the main stream of Atbara River, is always brown in color, specially in the autumn season. The highest turbidity value was recorded for the main stream of Atbara River, while, the maximum electric conductivity was found in Al Azasza boreholes. The total dissolved solids were greater in the ground water sources compared to that of the surface water sources. However, the total alkalinity  and  hardness  values  were  higher  in  the  ground  water  of  Al Azaza boreholes than that of all the other sources. On the other hand, the mineral contents (calcium, potassium, magnesium and sodium) were higher in the ground water. Fluorides, chlorides and bicarbonates were also higher in ground water. Similarly, were the contents of nitrates, nitrites and ammonia. However no carbonates were detected in Al Azaza and Abu Naja nor in Al Saraf dam raw water