Physicochemical characterization of sodium surfactin for oil and gas industry application

Introduction – Industry operators are becoming more critical of synthetic surfactants for various oil and gas operations. Principal among these concerns is the environmental degradation. As a result, there is increasing interest in the use of biosurfactant, including surfactin, in oil and gas operations. Therefore the need to improve its characteristics, hence performance becomes evident. Characteristics of cultures of surfactin (isolates) were reported. These characteristics could potentially change after synthesis and drying, hence the need for this study. Methodology - The methodology involved characterizing surfactin in aqueous media, and sodium chloride (NaCl) salt solution of 0.1–1.5M concentrations. Properties that influence active site for adsorption (functional group), dispersion (density, foaming), amount of dissolved minerals (pH and conductivity) among others, were analyzed at various surfactin dosages of 0.025 – 1.0%. Results − Results indicated foaming and solubility were excellent in aqueous solution, but significantly affected above 0.5M NaCl concentration. Aqueous surfactin had maximum density of 985.2kg/m3, however increases with increasing NaCl concentration. With pH of 7.1 at 1.0% dosage, aqueous surfactin will pose no corrosion problem to pipelines. Additionally, both surfactin dosage and change in salt concentration exhibited linear relationship effect with pH and conductivity. Infrared analysis confirms cyclic nature of sodium surfactin with lipopeptide chain linked to an aliphatic, hydrocarbon chain. Conclusion − These makes it suitable for use as dispersion agent, viscosity reduction for heavy crude transport, additive for drilling mud preparation, and potential candidate for surface activities, a desirable requirement for oil and gas applications. Keywords: Sodium surfactin, Bacillus subtilis, biosurfactant, physicochemical characteristic

Operative strategy for fistula-in-ano without division of the anal sphincter

We would like to thank Mr ER MacDonald for his contribution in data collection during the early years of the study. The material in this paper was presented as a poster at the annual meeting of the American Society of Colon and Rectal Surgeons held in Vancouver, Canada, May 2011.Peer reviewedPublisher PD

Screening for coping style increases the power of gene expression studies

Background: Individuals of many vertebrate species show different stress coping styles and these have a striking influence on how gene expression shifts in response to a variety of challenges. Principal Findings: This is clearly illustrated by a study in which common carp displaying behavioural predictors of different coping styles (characterised by a proactive, adrenaline-based or a reactive, cortisol-based response) were subjected to inflammatory challenge and specific gene transcripts measured in individual brains. Proactive and reactive fish differed in baseline gene expression and also showed diametrically opposite responses to the challenge for 80% of the genes investigated. Significance: Incorporating coping style as an explanatory variable can account for some the unexplained variation that is common in gene expression studies, can uncover important effects that would otherwise have passed unnoticed and greatly enhances the interpretive value of gene expression data

Seatbelt use and risk of major injuries sustained by vehicle occupants during motor-vehicle crashes: A systematic review and meta-analysis of cohort studies

BackgroundIn 2004, a World Health Report on road safety called for enforcement of measures such as seatbelt use, effective at minimizing morbidity and mortality caused by road traffic accidents. However, injuries caused by seatbelt use have also been described. Over a decade after publication of the World Health Report on road safety, this study sought to investigate the relationship between seatbelt use and major injuries in belted compared to unbelted passengers.MethodsCohort studies published in English language from 2005 to 2018 were retrieved from seven databases. Critical appraisal of studies was carried out using the Scottish Intercollegiate Guidelines Network (SIGN) checklist. Pooled risk of major injuries was assessed using the random effects meta-analytic model. Heterogeneity was quantified using I-squared and Tau-squared statistics. Funnel plots and Egger's test were used to investigate publication bias. This review is registered in PROSPERO (CRD42015020309).ResultsEleven studies, all carried out in developed countries were included. Overall, the risk of any major injury was significantly lower in belted passengers compared to unbelted passengers (RR 0.47; 95%CI, 0.29 to 0.80; I-2=99.7; P=0.000). When analysed by crash types, belt use significantly reduced the risk of any injury (RR 0.35; 95%CI, 0.24 to 0.52). Seatbelt use reduces the risk of facial injuries (RR=0.56, 95% CI=0.37 to 0.84), abdominal injuries (RR=0.87; 95% CI=0.78 to 0.98) and, spinal injuries (RR=0.56, 95% CI=0.37 to 0.84). However, we found no statistically significant difference in risk of head injuries (RR=0.49; 95% CI=0.22 to 1.08), neck injuries (RR=0.69: 95%CI 0.07 to 6.44), thoracic injuries (RR 0.96, 95%CI, 0.74 to 1.24), upper limb injuries (RR=1.05, 95%CI 0.83 to 1.34) and lower limb injuries (RR=0.77, 95%CI 0.58 to 1.04) between belted and non-belted passengers.ConclusionIn sum, the risk of most major road traffic injuries is lower in seatbelt users. Findings were inconclusive regarding seatbelt use and susceptibility to thoracic, head and neck injuries during road traffic accidents. Awareness should be raised about the dangers of inadequate seatbelt use. Future research should aim to assess the effects of seatbelt use on major injuries by crash type

Enhancement of Feed Source through Three Dimensional Printing.

The three-dimensional printed wideband prototype (WBP) was proposed, which is able to enhance the horn feed source by generating a more uniform phase distribution that is obtained after correcting aperture phase values. The noted phase variation obtained without the WBP was 163.65∘ for the horn source only, which was decreased to 19.68∘, obtained after the placement of the WBP at a λ/2 distance above the feed horn aperture. The corrected phase value was observed at 6.25 mm (0.25λ) above the top face of the WBP. The use of a five-layer cubic structure is able to generate the proposed WBP with dimensions of 105 mm × 105 mm × 37.5 mm (4.2λ× 4.2λ× 1.5λ), which can improve directivity and gain by 2.5 dB throughout the operating frequency range with a lower side lobe level. The overall dimension of the 3D printed horn was 98.5 mm × 75.6 mm × 192.6 mm (3.94λ× 3.02λ× 7.71λ), where the 100 % infill value was maintained. The horn was painted with a double layer of copper throughout its surface. In a design frequency of 12 GHz, the computed directivity, gain, side lobe level in H- and E- planes were 20.5 dB, 20.5 dB, -26.5 dB, and -12.4 dB with only a 3D printed horn case and, with the proposed prototype placed above this feed source, these values improved to 22.1 dB, 21.9 dB, -15.5 dB, and -17.5 dB, respectively. The realized WBP was 294 g and the overall system was 448 g in weight, which signifies a light weight condition. The measured return loss values were less than 2, which supports that the WBP has matching behavior over the operating frequency range

Wide Dual-Band Circularly Polarized Diecletric Resonator: Innovative Integration of a Single Hybrid Feed and Thin Grounded Metasurface.

This article presents an application of a grounded substrate-based metasurface for hosting dielectric resonators (DRs), enabling a wide dual-band circularly polarized (CP) operation. The antenna structure comprises centrally positioned rectangular DRs, one above the other, along with a 7 × 7 square-slotted metasurface. The metasurface and DRs are hosted above a grounded substrate, which is fed through a single coaxial feed placed at a specific angle, employing a modified upper probe of the coaxial feed. The proposed hybrid technique utilizes the combined benefits of the feed angle and a well-matched metasurface, resulting in performance improvement. Notably, a measured impedance bandwidth of 88.1% for |S11| is achieved within the frequency range of 4.0 GHz to 10.3 GHz. Furthermore, the antenna design exhibits two overlapping measured 3-dB axial ratio (AR) bandwidths: 23.62% from 4.25 GHz to 5.4 GHz and 5.12% from 7.6 GHz to 8 GHz. The peak gain of the antenna is measured at 8.4 dBic. Consequently, this innovative single-feed antenna design, characterized by its compact profile, holds significant potential for realizing multi-band operations. Furthermore, the developed antenna is well-suited for deployment in indoor radio links and INSAT applications

Biomass expansion factors of Olea ferruginea (Royle) in sub tropical forests of Pakistan

Wood biomass gives information about total productivity of the forest as well as individual tree. Olea ferruginea (Royle) which is small and evergreen is widely distributed in native sub tropical forests of Pakistan and extensively used as fuelwood domestically. This study was carried out in the sub tropical forests of Pakistan at 33° 38’ north and 73° 00’ east latitude and longitude, respectively, and at an elevation of 917 m. Trees with exploitable diameter were selected randomly from the entire forest.Destructive sampling techniques were used for measuring biomass (kgm-3) in all the tree components. For this purpose, 5 trees were felled and the biomass of each component of the tree including main stem, branches, leaves, twigs and roots were estimated separately using volume, weight and density. The generic data of wood density (kgm-3) was used to determine the biomass (kg). The study showed that average contribution of stem portion of the tree was 49.01% of the total tree biomass, and branches showed 31.17%, leaves 1.98%, twigs 1.05% and roots 16.65% of the total tree biomass. So, it was found that the major part of the total tree biomass was present in the stem portion of O. ferruginea. Totalvolume of the tree was also found to be dependent on the diameter of the tree. Mean volume of the tree was 0.475 ± 0.07 m3. The prepared  biomass expansion factor will be helpful in estimating productivity, carbon stocks and yield of the forest.Key words: Biomass, biomass expansion factor, tree volume, Olea ferruginea