RESUMEN
Conventional conductive homopolymers such as polypyrrole and poly-3,4-ethylenedioxythiophene (PEDOT) have poor mechanical properties, for the solution to this problem, we tried to construct hybrid composites with higher electrical properties coupled with high mechanical strength. For this purpose, Kevlar fibrous waste, conductive carbon particles, and epoxy were used to make the conductive composites. Kevlar waste was used to accomplish the need for economics and to enhance the mechanical properties. At first, Kevlar fibrous waste was converted into a nonwoven web and subjected to different pretreatments (chemical, plasma) to enhance the bonding between fiber-matrix interfaces. Similarly, conductive carbon particles were converted into nanofillers by the action of ball milling to make them homogeneous in size and structure. The size and morphological structures of ball-milled particles were analyzed by Malvern zetasizer and scanning electron microscopy. In the second phase of the study, the conductive paste was made by adding the different concentrations of ball-milled carbon particles into green epoxy. Subsequently, composite samples were fabricated via a combination of prepared conductive pastes and a pretreated Kevlar fibers web. The influence of different concentrations of carbon particles into green epoxy resin for electrical conductivity was studied. Additionally, the electrical conductivity and electromagnetic shielding ability of conductive composites were analyzed. The waveguide method at high frequency (i.e., at 2.45 GHz) was used to investigate the EMI shielding. Furthermore, the joule heating response was studied by measuring the change in temperature at the surface of the conductive composite samples, while applying a different range of voltages. The maximum temperature of 55 °C was observed when the applied voltage was 10 V. Moreover, to estimate the durability and activity in service the ageing performance (mechanical strength and moisture regain) of developed composite samples were also analyzed.
RESUMEN
In this study, we developed multifunctional and durable textile sensors. The fabrics were coated with metal in two steps. At first, pretreatment of fabric was performed, and then copper and silver particles were coated by the chemical reduction method. Hence, the absorbance/adherence of metal was confirmed by the deposition of particles on microfibers. The particles filled the micro spaces between the fibers and made the continuous network to facilitate the electrical conduction. Secondly, further electroplating of the metal was performed to make the compact layer on the particle- coated fabric. The fabrics were analyzed against electrical resistivity and electromagnetic shielding over the frequency range of 200 MHz to 1500 MHz. The presence of metal coating was confirmed from the surface microstructure of coated fabric samples examined by scanning electron microscopy, EDS, and XRD tests. For optimized plating parameters, the minimum surface resistivity of 67 Ω, EMI shielding of 66 dB and Ohmic heating of 118 °C at 10 V was observed. It was found that EMI SH was increased with an increase in the deposition rate of the metal. Furthermore, towards the end, the durability of conductive textiles was observed against severe washing. It was observed that even after severe washing there was an insignificant increase in electrical resistivity and good retention of the metal coating, as was also proven with SEM images.
RESUMEN
OBJECTIVE: Patients' attitude towards medical students' presence during treatment depends on the cultural values of the society. This study was conducted to find out the patients' receptiveness in our society to be involved in teaching process for medical students during consultation in out patient department of a teaching hospital in Karachi Pakistan. METHODOLOGY: This cross sectional study was conducted in the surgical Out Patient Department (OPD) at Dow University Hospital from May 2012 to June 2012. Four hundred and eleven patients consented for participation through non probability purposive sampling, in which 279 patients were from morning clinics in the presence of students for clinical teaching, while 132 patients participated through evening clinics of surgery, when students were not present for comparison in specific dimensions of care for patients' satisfaction. RESULTS: Majority of patients 293 (71%) agreed with the teaching of students during consultation and they feel they are contributing in future doctor's teaching, only 24% patients disagreed. Fifty two percent of patients who disagreed reported interference in privacy, 34% reported interference in consultation and 43% felt it resulted in prolong waiting time due to teaching. CONCLUSION: Majority of the patients agree to be part of teaching for medical students and this study can be used to assess the educational interventions designed to improve the patient based teaching.
RESUMEN
OBJECTIVE: To determine the trends of academic misconduct in undergraduate students of different private and government section medical institutes. METHODOLOGY: This cross sectional study was conducted at three medical colleges of Karachi, Pakistan. The students were evaluated by giving a self reported questionnaire containing various questions assessing their educational dishonesty and cheating behaviors. RESULTS: A total of 274 students from different years completed the questionnaire. Mean age was 21.48 ± 1.89 years. Most of the students were in 4(th) year (n=86; 31.3%). There were 182 (66.5%) females and 92 (33.5%) males. Majority of the students (n=155; 55.1%) accepted that they have cheated at least once. There was no significant difference regarding acceptance of cheating among different years of study (p=0.23) however females were found to accept cheating more as compared to males (p=0.036). First year students were found more to ask teachers for answers during OSCE (p=0.01). A large number of students accepted that they mark proxy for their friends (85.7%) and also ask their friends to mark proxy for them (85.03%). Nearly half (44.02%) of the students rotating in wards also admitted to write fake histories. CONCLUSION: A large number of medical students admitted cheating and involvement in other academic misconduct. We need to improve our educational system, formally add professional session and strict disciplinary action should be taken against those who are found guilty.
