Application of Geographic Information System for the Installation of Surge Arrestors on over head 132 k-v Power Line

Power system consists of generation, transmission and distribution of electrical energy. Transmission lines transport the desired amount of electrical power from one place to another. The Protection of Power line is a very important factor in smooth transfer of electric power. Lightning is a major cause of overhead line faults.It is necessary to protect the power apparatus from over volts in electric system, namely lighting over voltages & switching over voltages. The objectives of this study is to protect the power system equipment's from lightning using geographic information system approach A Geographical Information System (GIS) is a collection of software's that allows you to create, visualize, query and analyse geographic data.This paper presents the idea of installing line surge arrestors by marking the exact location of towers using a multispectral satellite image and image processing software with the help of gps points taken on the ground. A case study of 132 k-v existing double circuit line from Sheik Muhammadi 500 k-v grid to 132 k-v city grid Peshawar is considered for results where as input data to GIS is in the form of spot-5 satellite image having 2.5m resolution

Effect of early release of tourniquet in total knee arthroplasty

Objective: To evaluate whether tourniquet release intraoperatively is better than postoperative release in reducing overall blood loss, duration of surgery, duration of tourniquet, length of hospital stay, wound related complications and transfusion requirement. Study Design: Comparative study. Place and Duration of Study: Department of Surgery, The Aga Khan University Hospital, Karachi, from January 2004 to June 2007. Methodology: One hundred and thirty patient files were reviewed retrospectively. Patients were divided into two groups. Group-A consisted of 65 patients with early deflation of tourniquet and group-B comprised of 65 patients with the release of tourniquet after applying compressive dressing. Total blood loss (determined by Gross method) and other study variables were noted as per objective and computed.Results: There were 22 males and 108 females with comparable BMI. All had undergone posterior stabilized cemented total knee replacement. Calculated blood loss was 1.208 L and 1.108 L in group-A and B respectively (p = 0.27). Significant increase in duration of surgery was noted in group-A patients. Four patients in group-B showed complication related to wound with 3 being minor and 1 requiring additional operation room visit. Mean length of hospital stay was 9 days. Transfusion frequency was higher in group-B despite comparable postoperative haemoglobin values. Conclusion: Intraoperative tourniquet release does not reduce overall blood loss with no effect in conserving blood after total knee replacement, however, this group had relatively shorter hospital stay

Transfusion practice in orthopedic patients: do we really need it?

Abstract OBJECTIVE: To determine the proportion of inappropriate transfusions in patients undergoing orthopaedic surgery at a tertiary care university hospital, and factors associated with inappropriate transfusions. METHODS: The prospective study was conducted at Aga Khan University Hospital, Karachi, from December 2008 to September 2009, and comprised patients admitted to the Orthopaedic Department and received transfusion of at least one packed cell. Patients were divided into four groups: A, those with haemoglobin \u3c 7, B, haemoglobin 7.1-10 without ischemic heart disease, C, haemoglobin 7.1-10 with ischemic heart disease, and D, haemoglobin \u3e10. Variables recorded were, pre-transfusion haemoglobin level, co-morbids, symptoms of hypovolemia, pre-transfusion volume replacement with fluids, transfusion reactions, and haemoglobin after 48 hours. Indications of transfusion were assessed in accordance with available data. RESULTS: Of the 126 patients, 65(52%) were males and 61(48%) were females. There were 18(14%) patients in group A, 88(70%) in group B, 12(10%) in group C, and 8(6%) in group D. Overall, Overall, 44(35%) were transfused appropriately according to the criteria, and 82(65%) were inappropriate. CONCLUSIONS: The number of inappropriate transfusion was quiet high and demands revision of institutional policy of packed cell transfusion in accordance with available guidelines

Minimally invasive plate osteosynthesis for tibial plateau fractures.

Purpose:To evaluate radiological and clinical outcome of minimally invasive plate osteosynthesis (MIPO) for tibial plateau fractures. Methods: 35 men and 6 women aged 19 to 75 (mean, 40, standard deviation [SD], 14) years underwent MIPO for displaced tibial plateau fractures. According to the Schatzker system, the tibial plateau fractures were classified as types I (n=3), II (n=9), III (n=11), IV (n=6), V (n=7), and VI (n=5). Six Patients had open fractures, 2 of them underwent debridement before MIPO. 10 Patients needed additional bone grafting. Radiological (at immediate postoperation) and clinical (at the 12-month follow-up) assessments based on the Rasmussen anatomic and functional scoring system were recorded using a proforma. Patients with acceptable and unacceptable outcomes were compared in terms of age. Results: The mean Rasmussen anatomic score was 15.1 (SD, 2.2, range, 10-18), the mean Rasmussen functional score was 25.3 (SD, 3.2, range, 14-29), and the mean range of knee motion was 118 (SD, 10, range, 90-140) degrees. Anatomic outcome was excellent in 10, good in 28, and unacceptable in 3 Patients (one each had Schatzker type-I, -II, and -III fractures). 27 (71%) of the 38 Patients with acceptable anatomic outcome were aged 45 years or younger, whereas 2 (67%) of the 3 Patients with unacceptable anatomic outcome were aged 60 years or older (p=0.001). Functional outcome was excellent in 18, good in 19, and unacceptable in 4 Patients (2 had Schatzker type-III and another 2 had Schatzker type-I or -II fractures). 37 of the Patients had a range of knee motion of 120 degrees or more, 27 (73%) of them were aged 45 years or younger, whereas 3 (75%) of the 4 Patients with unacceptable functional outcome were aged 60 years or older (p=0.001). Conclusions: MIPO for tibial plateau fractures achieved good outcome with minimal soft-tissue complications. Older age was the predictor of unacceptable outcome

Developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a spectrum of anatomical abnormalities of the hip joint in which the femoral head has an abnormal relationship with the acetabulum. Most studies report an incidence of 1 to 34 cases per 1,000 live births and differences could be due to different diagnostic methods and timing of evaluation. Risk factors include first born status, female sex, positive family history, breech presentation and oligohydramnios. Clinical presentations of DDH depend on the age of the child. Newborns present with hip instability, infants have limited hip abduction on examination, and older children and adolescents present with limping, joint pain, and/or osteoarthritis. Repeated, careful examination of all infants from birth and throughout the first year of life until the child begins walking is important to prevent late cases. Provocative testing includes the Barlow and Ortolani maneuvers. Other signs, such as shorting of the femur with hips and knees flexed (Galeazzi sign), asymmetry of the thigh or gluteal folds, and discrepancy of leg lengths are potential clues. Treatment depends on age at presentation and outcomes are much better when the child is treated early, particularly during the first six months of life

Passivity-based Rieman Liouville fractional order sliding mode control of three phase inverter in a grid-connected photovoltaic system

Photovoltaic (PV) system parameters are always non-linear due to variable environmental conditions. The Maximum power point tracking (MPPT) is difficult under multiple uncertainties, disruptions and the occurrence of time-varying stochastic conditions. Therefore, Passivity based Fractional order Sliding-Mode controller (PBSMC) is proposed to examine and develop a storage function in error tracking for PV power and direct voltage in this research work. A unique sliding surface for Fractional Order Sliding Mode Control (FOSMC) framework is proposed and its stability and finite time convergence is proved by implementing Lyapunov stability method. An additional input of sliding mode control (SMC) is also added to a passive system to boost the controller performance by removing the rapid uncertainties and disturbances. Therefore, PBSMC, along with globally consistent control efficiency under varying operating conditions is implemented with enhanced system damping and substantial robustness. The novelty of the proposed technique lies in a unique sliding surface for FOSMC framework based on Riemann Liouville (R-L) fractional calculus. Results have shown that the proposed control technique reduces the tracking error in PV output power, under variable irradiance conditions, by 81%, compared to fractional order proportional integral derivative (FOPID) controller. It is reduced by 39%, when compared to passivity based control (PBC) and 28%, when compared to passivity based FOPID (EPBFOPID). The proposed technique led to the least total harmonic distortion in the grid side voltage and current. The tracking time of PV output power is 0.025 seconds in PBSMC under varying solar irradiance, however FOPID, PBC, EPBFOPID, have failed to converge fully. Similarly the dc link voltage has tracked the reference voltage in 0.05 seconds however the rest of the methods either could not converge, or converged after significant amount of time. During solar irradiance and temperature change, the photovoltaic output power has converged in 0.018 seconds using PBSMC, however remaining methods failed to converge or track fully and the dc link voltage has minimum tracking error due to PBSMC as compared to the other methods. Furthermore, the photovoltaic output power converges to the reference power in 0.1 seconds in power grid voltage drop, whereas other methods failed to converge fully. In addition power is also injected from the PV inverter into the grid at unity power factor

Motor and Somatosensory Evoked Potential Monitoring Without Wakeup Test during Scoliosis Surgery

Background: Available evidence suggests that Transcranial electric motor evoked potentials and somatosensory evoked potential are safe methods to check the integrity of the spinal cord during spine deformity correction surgery. We compare the efficacy of Transcranial electric motor evoked potentials and somatosensory evoked potential to detect the nerve injury during Scoliosis surgery. Objectives: To demonstratethe advantages of combined motor and sensory evoked potential monitoring during Scoliosis surgery. Methods: We analyzed records of 65 (48 female and 17 male) Scoliosis surgery cases of Transcranial electric motor evoked potential and Somatosensory evoked potential.Mean age was 15.6 years. Patients who showed significant (at least 55%) of unilateral or bilateral amplitude loss , for at least five to ten minutes during the intervention in scoliosis surgery under total intravenous anesthesia will be included. Results: From 65 patients during surgery seventeen patients have a significant or complete drop of baseline amplitude on transcranial electric motor evoked potentials. Thirteen patients have the complete return of baseline amplitude by surgeon intraoperative intervention, whereas four patients havea reversal of motor response after 8 hours post-operatively. Transcranial electric motor evoked potential monitoring was 100% specific and 100% sensitive, whereas Somatosensory evoked potential was 100% specific and 85% sensitive. Conclusions: SSEPs and MEPs , in combination give accurate and quick information of nerve or spinal cord insult intraoperatively

Vacuum assisted closure-utilization as home based therapy in the management of complex diabetic extremity wounds

Objective: Vacuum assisted closure is a reported technique to manage complex wounds. We have utilized this technique by using simple locally available material in the management of our patients on outpatient basis. The objective of this study is to present our experience. Methods: This study was conducted from June 2011 to June 2013 at Dow University Hospital and Aga Khan University Hospital, Karachi. There were 38 patients managed with vacuum assisted closure. Mean age was 56±7.8 years. Twenty three patients presented with necrotizing fasciitis and 15 patients with gangrene. Lower limbs were involved in majority of the patients. Debridement or amputations were done. Vacuum dressing was changed twice weekly in outpatient department. Wounds were closed secondarily if possible or covered with split thickness skin graft in another admission. Results: All the wounds were successfully granulated at the end of vacuum therapy. Mean hospital stay was 7.5 days. Vacuum dressing was applied for a mean of 20 days. There was reduction in the size of the wound. Thirteen patients underwent secondary closure of the wound under local anesthesia, 18 patients required coverage with split thickness skin graft and 7 patients healed with secondary intention. Conclusion: Vacuum assisted closure appeared to be an effective method to manage complex diabetic wounds requiring sterile wound environment

Salvage of infected non-union of the tibia with an Ilizarov ring fixator.

Abstract PURPOSE: To review outcomes of 24 patients who underwent Ilizarov ring fixation for infected nonunion of the tibia. METHODS: Medical records of 21 men and 3 women aged 13 to 74 (mean, 38) years who underwent Ilizarov ring fixation for infectednon-union of the tibia were reviewed. The mean bone defect was 3.3 (range, 2-5) cm. The mean time from injury to presentation was 11.9 (range, 1-36) months. The mean number of previous surgeries was 2 (range, 0-14). A local flap was used in 2 patients and a free flap was used in one patient. Nine of the patients underwent Ilizarov ring fixation without soft tissue and bony resection, as inadequate stability was the reason for non-union. Patients were assessed using the Association for the Study and Application of the Method of Ilizarov criteria. RESULTS: Patients were followed up for a mean of 11 (range, 8-46) months. Functional outcome was excellent in 8 patients, good in 12, fair in 2, and failure in one, whereas bone union outcome was excellent in 6 patients, good in 14, fair in one, and poor in 2. The mean time to union was 8 (range, 3-31) months. The mean external fixation index was 4.2 (range, 1.5-15.7) cm/month. Complications encountered were pin tract infection (n=5), re-fracture (n=2), soft tissue impingement by Ilizarov rings (n=2), recurrence of wound infection (n=1), mal-union (n=1), and mortality (n=1). CONCLUSION: Ilizarov ring fixation is a viable option for infected non-union of the tibia. Adequate assessment of bone union is crucial before removal of fixator to prevent re-fracture