Non-linear multi-scale finite element method for prediction of tensile behaviour of carbon nanotube-reinforced polymer composites

The ability of using carbon nanotubes as the strongest and stiffest elements in nanoscale composites remains a powerful motivation for research in this area. This paper describes a finite element modelling appropriate for the numerical prediction of the mechanical behaviour of polypropylene which is reinforced with single-walled carbon nanotubes. A multi-scale representative volume element is proposed for modelling the tensile behaviour of carbon nanotube reinforced composites. Within the representative volume element, the reinforcement is modelled according to its atomistic microstructure. A model based on the modified Morse interatomic potential is used for simulating the isolated carbon nanotube. In this work, the matrix is modelled as a medium in a form of a continuum by utilizing solid elements and in order to describe its behaviour, an appropriate non-linear material model is adopted. A cohesive zone model is assumed between the nanotube and the matrix with an ideal bonding until the interfacial shear stress exceeds the corresponding strength. By using the representative volume element, a unidirectional nanotube/ polymer composite was modelled and the results were compared to the corresponding rule-of-mixtures predictions. The effect of interfacial shear strength on the tensile behaviour of the nanocomposite was also studied. The influence of adding a single-walled carbon nanotube to the polymer is discussed and the results show that Young’s modulus and tensile strength of the polymer significantly increase in the presence of carbon nanotubes

Aboveground carbon stock potential of teak (tectona grandis) under different land use system in Balung plantation, Tawau Sabah

Assessment of aboveground carbon stock in different teak plantation systems was conducted in Balung River Plantation, Tawau, Sabah. The objective of this study is to determine the potential of teak as the main tree components to increase the above ground carbon stock in different land use system. The above ground carbon stock of agroforestry and mixed plantation system of teak (Tectona grandis) were compared with natural forest and monoculture plantation of the species. The agroforestry combinations investigated are agroforestry system 1, teak (18 years) with snake fruit (8 years) and agarwood (8 years); agroforestry system 2, teak (17 years) with coffee (14 years); and also mixed timber plantation system, teak (18 years) with agarwood (8 years); while 20 years teak monoculture plantation and natural forest reserve was set up as a control. A random systematic sampling method was used in conducting field inventory. The methodologies used include the measurement of height and diameter breast height (DBH) of trees within a 50 m x 50 m plot dimension (for plantation) and 30 m x 30 m (forest). Allometric equations were used to derive the field measured attributes into stand biomass while carbon stock was estimated as 50 percent from the total biomass. The result shows the accumulation of carbon stock goes in the following order: forest reserve (213.84 t C/ha) > mixed timber plantation (69.94 t C ha-1 ) > agroforestry system 2 (37.75 t C/ha) > agroforestry system 1 (37.34 t C/ha) > teak monoculture (34.53 t C/ha) witnessing the teak trees to increase the total aboveground carbon stock in agroforestry and mixed timber plantation system by more than 60 percent. This study suggested that teak has great potential in transforming a low biomass land use into a carbon-rich tree based systems

Carbon stock estimation of agroforestry system in Tawau, Sabah

Studies on total aboveground carbon (TAC) and belowground carbon (TBC) stock has been conducted in Balung Plantation, Tawau, Sabah. The main objective of the study was to determine the above and below ground carbon stock in agroforestry system. The combination of agroforestry systems with different ages were investigated, which is oil palm (25 years) and agarwood (7 years), oil palm (20 years) and agarwood (7 years), and oil palm (17 years) and agarwood (5 years). Monoculture of oil palm (16 years) and Tawau Hill Park forest reserve was set as control. A random systematic sampling method was used in conducting field inventory and soil sampling. The size of the sampled area in agroforestry and monoculture is 3 × 50m × 50m, while for forest reserve, the sampled area is 3 x 30m x 30m. Allometric equations were used to calculate the stand biomass. Sampling for organic and shrub layers were collected in a square frame (1m × 1m). Soil samples and bulk density was collected from three different layers which are 0 – 5 cm, 5 – 10 cm and 10 – 30 cm in randomly located sites within the plots. Soil samples, organic and shrub layer were analyzed using CHN628 series for carbon content. Result shows that the amount of total carbon stock in agroforestry was 79.12 tan C ha-1, 85.39 tan C ha-1 and 78.27 tan C ha-1, respectively. Monoculture of oil palm (16 years) has 76.44 tan C ha-1 while Tawau Hill Park forest reserve has total carbon stock at 287.38 tan C ha-1. Forest reserve stand has the highest total carbon stock compared to agroforestry and monoculture systems. But, in terms of soil carbon, forest reserve has the lowest TBC compared to agroforestry and monoculture systems. ANOVA was conducted to explore the impact of planting systems on total carbon stock. There was a statistically significant difference at the p < .05 level for soil carbon, living tree and organic layer between agroforestry, monoculture and forest reserve. Good crop and fertilizer management in agroforestry and monoculture systems helps in increasing soil organic carbon (SOC)

Molluscicidal and feeding deterrent activity of crude plant extracts on Pomacea maculate Perry

This study was focused on molluscicidal effect and feeding deterrent activity of saponin from five different plant materials; Andrographis paniculata, Entada spiralis, Ficus deltoidea, Furcraea selloa and Ipomoea batatas. Crude plant extracts were prepared from plant powders using methanol. The crude extracts were then tested on Pomacea maculata using five different concentrations (5, 10, 15, 20 and 25 ppm, respectively) against niclosamide (control). After 72 h of exposure, the highest percentage of mortality of 80% was achieved from 15 ppm of F. selloa. Two analyses were conducted to observe the feeding deterrent activity and after 24 h, both analyses demonstrated the feeding deterrent activity in both crude extracts (F. selloa and E. spiralis) similar in niclosamide

Development of Saponin based Nano emulsion formulations from Phaleria macrocarpa to Control Aphis gossypii

Aphis gossypii is one of the most devastating insect pests of agricultural crops due to its polyphagous nature. A sustainable environment friendly method to manage this pest is botanical aphicides because of their easily biodegradability and overall safety. In this study, saponin based nano emulsions from Phaleria macrocarpa with Termul 1284 and methyl oleate /rapeseed oil were formulated and tested against A. gossypii for their efficacy in both laboratory and glasshouse conditions.&nbsp; Results exhibited that all three formulated nano emulsions effectively suppressed A. gossypii population under laboratory and glasshouse conditions. However, TR3 revealed highest repellency (62%) and mortality percentage (100%) with lowest LC50 (1516 mg-L1) and LT50 (27.50 h), following by TM1 repellency (58%) and mortality percentage (98%) with lowest LC50 (1732 mg-L1) and LT50 (34.43 h). Glasshouse bioassay also revealed that TR3 (Termul 1284+rapeseed oil) and TM1 (Termul 1284+methyl oleate) could suppress A. gossypii population at LC50 values of 2512 and 2904 mg-L1 at 72 hours and LT50 values of 68.7 and 71.2 hours at 10000 mg-L1 respectively. Therefore, these both formulations could be considered as eco-friendly alternative approach in pesticides technology

Effect of intrapartum pethidine on the neonatal outcome: is it duration related?

Objectives: To study the effect of pethidine on the intrapartum fetal heart rate (FHR) pattern and to assess the neonatal outcome with regards to the interval between pethidine administration to delivery of the fetus. Materials: 73 healthy women intrapartum from labour suite hospital Tengku Ampuan Afzan, Kuantan, Malaysia Methods: This is a prospective observational study done on 73 healthy consented women with singleton pregnancy at term . All fetus were normal, vertex presentation with reactive FHR tracing before pethidine administration. FHR recording were performed for 40 minutes prior to and one hour post pethidine. Cervical dilatation of all patients ≤ 4 cm at time of pethidine administration. Intramuscular pethidine 1mg/kg was given as an intrapartum analgesia. The study sample was divided into two groups, first group delivered within 4 hours and second group delivered more than 4 hours after the pethidine administration. The data were analysed by SSPS 17.0. Results: the mean age of the recruited patients is 28.15 ± 6.15 years and mean gestational age of 39.14 ± 1.094 weeks. The mean duration from pethidine administration to delivery is 296.48 ± 173.65 minutes (4 hours and 56 minutes). Four (5.5%) cases had suspicious CTG 1 hour post pethidine, 1 with absence of acceleration for 45 minutes and 3 cases with early deceleration lasted for 60 to 90 minutes. Out of 73 patients, 38 babies delivered within 4 hours and 35 delivered after 4 hours of pethidine. All neonates delivered with good Apgar Score (AS), 8 at 1 minute and 9 at 5 minute except 1 with AS of 5 at 1 min and 7 at 5 min which delivered more than 4 hours after pethidine. Sixteen (21.9%) cases were admitted to the Neonatal Intensive Care Unit (NICU). Eleven (68.75%) cases were admitted due to neonatal sedation from the delivery group less than 4 hours after pethidine. Five (31.25%) cases from the delivery group more than 4 hours, 4 cases with a diagnosis of transient tachypnea of newborn and 1 secondary to meconium aspiration syndrome (MAS). All discharge to mother after 24 hours, non required ventilation apart from the one with MAS which required ventilation for one day and longer admission. Despite of the higher number of those require admission in the less than 4 hours group, it was not statistically significant with P value of 7.44. Conclusions: Pethidine can be used as an intrapartum analgesia which is safe, easily available without major effect on fetal heart rate pattern and neonatal outcome even if given in advance stage of labour

Maternal outcome of prenatally diagnosed lethal fetal anomalies: a year review

Objectives: To determine maternal morbidities in relation to prenatal diagnosis of lethal fetal anomalies and termination of pregnancy (TOP). Materials: Twenty five patients with prenatal diagnosis of lethal fetal anomalies in Hospital Tengku Ampuan Afzan, Kuantan, Malaysia. Methods: This was a retrospective review in Hospital Tengku Ampuan Afzan, Kuantan, Malaysia in the year of 2011. All patients diagnosed prenatally to carry lethal fetal anomalies was reviewed. Data regarding maternal morbidities and outcome was collected from patients’ case note in the hospital record office. Analysis was done by using SPSS version 17.0. Results: Twenty five pregnant patients were diagnosed with lethal fetal anomalies via ultrasound with or without genetic study. The patients’ mean age was 29.9±6.3 years old. The mean gestational age at diagnosis of lethal fetal anomalies and at TOP or delivery were 26.5±7.4 and 28.7±7.8 weeks respectively. The lethal fetal anomalies included fetuses with multiple structural abnormalities (40%), anencephaly or severe encephalocele (32%), non-immune hydrops fetalis (16%) and syndromic fetuses (12%) i.e. Pentalogy of Cantrell and Edward’s syndrome. Seven (28%) patients had early counseling and TOP at the gestation of <22 weeks. Beyond 22 weeks gestation, 8 (32%) patients had TOP and 10 (40%) patients had spontaneous delivery. Twenty (80%) patients delivered or aborted vaginally, 3 (12%) patients with assisted breech delivery, and 2 (8%) patients with abdominal delivery. The abdominal deliveries were for transverse lie in labour and emergency hysterotomy for failed induction complicated by hysterectomy due to intraoperative finding of ruptured uterus. Overall, the associated adverse events included abnormal lie during delivery (16%), symptomatic polyhydramnios requiring amnioreduction (16%), post-partum haemorrhage (12%), retained placenta (12%), blood transfusion (8%), uterine rupture (4%) and endometritis (4%). Mean duration of hospital stay was 6.6±3.7 days. Conclusions: Prenatal diagnosis and TOP at an early gestation may reduce maternal morbidities and improve the outcom

Monoamniotic twin pregnancy: is there a need for frequent fetal-doppler surveillance?

Monoamniotic twin pregnancy is a rare type of twin pregnancy which poses risk of cord entanglement and sudden death of either one or both fetuses. The role of antenatal surveillance by Ultrasound Doppler for umbilical cord and ultrasonic evidence of cord entanglement or knotting may predict the pregnancy outcome but yet unavoidable. The discussion will include antenatal surveillance in this rare type of pregnanc

Are our patients different? A 5-year review of cervical cancer cases managed in tertiary Gynaecological Cancer Unit in Malaysia

Objective: The purpose of this review is examine the clinicopathological characteristics of cervical cancer treated in this situation from 2010 to 2014. Method: This is an observational retrospective study. All cases of cervical cancer treated in this institution from January 2010 until December 2014 were reviewed. Clinicopathological characteristics were recorded and analysed using SPSS version 20. Result:There were 31 cases of cervical carcinoma identified during that 5-year period. The mean age at diagnosis was 51.0 0±12.7 years(range,29-78 years).The majority of them (87%) were diagnosed before the age 70. None of the patients participated in cervical cancer screening programme and as a result less than 10% of women were diagnosed following an abnormal pap smear test. More than 90& were symptomatic, out of 82% were abnormal per vaginal bleeding and the remaining 11% and 7% were postcoital bleeding and compressive symptoms respectively. Risk factors for cervical cancer were identified in less than a third of the patients. Premorbid medical conditions were identified in only 50% of patinets and 94% were hypertension and/or diabetes mellitus. Similarly, the majority (94%) were categorised as having either ECOG functional class 0 and 1 i.e. 81 % and 13% respectively. There was an equal breakdown between squamous cell carcinoma(SCC) and adenocarcinoma(ACC), which was 48.4% each and the remaining 3.2% were others. For SCC,nearly all(94%)were large cell non-keratinising SCC with only 6% were large cell keratinising SCC subtype. As for ACC, the majority type were mucious endocervical subtype (47%), 40% were classified and the remainig 13% were others. Almost all (96.8%) patients had an examination under anaesthesia (EUA) and diagnostic imaging in the form of computer axial tomography(CT) scan to rule out the locoregional and distance metasis. Just above the half(55%) of the patient presented with stage 1b i.e. 29% 1b1 and another 26% 1b2. Stage 2 contributed to about 23% and which 13% were 2a and 10% were 2b. Stage 3 and stage 4 disease accounted for the remaining 9% and 13% respectively. About two-third of patients went on to have treatment with us and the remaining one- third sought an alternative form of treatment. Out of this, 47% had Wertheim’s hysterectomy,6% had neoadjuvant chemotherapy, followed by Wertheim’s hysterectomy, 20% had concurrent chemoradiation and the remaining 13% had palliative treatment. From the 16 patients who had Wertheim’s hysterectomy, 8 of them (50%) required further adjuvant treatment in the form of radiotherapy. Conclusion: The incidence of adinocarcinoma is higher than other study. Only one third of our patients had early disease at presentation, which is likely to poor cervical smear uptake. Our adjuvant radiotherapy rate was higher compared to others as most of our patients preferred surgery (even they needed adjuvant radiotherapy) compared to concurrent radiotherapy alone

Maternal outcome of prenatally diagnosed lethal fetal anomalies: a year review

This was a retrospective review in Hospital Tengku Ampuan Afzan, Kuantan, Malaysia In the year of 2011. All patients diagnosed prenatally to carry lethal fetal anomalies was Reviewed. The outcome of the pregnancy including type of labour, mode of induction and delivery, and associated morbidities during antenatal, intrapartum, and postpartum period was analyse