Numerical investigation of the heterogeneous combustion processes of solid fuels

Two-phase computational modelling based on the Euler–Euler was developed to investigate the heterogeneous combustion processes of biomass, in the solid carbon phase, inside a newly designed combustion chamber (Model 1). A transient simulation was carried out for a small amount of carbon powder situated in a cup which was located at the centre of the combustion chamber. A heat source was provided to initiate the combustion with the air supplied by three injection nozzles. The results show that the combustion is sustained in the chamber, as evidenced by the flame temperature. An axisymmetric combustion model (Model 2) based on the Euler–Lagrange approach was formulated to model the combustion of pulverized coal. Three cases with three different char oxidation models are presented. The predicted results have good agreement with the available experimental data and showed that the combustion inside the reactor was affected by the particulate size. A number of simulations were carried out to find the best values of parameters suitable for predicting NOx pollutants

Wounding patterns and human performance in knife attacks: optimising the protection provided by knife-resistant body armour

Stab attacks generate high loads,1 and to defeat them, armour needs to be of a certain thickness and stiffness.2,3 Slash attacks produce much lower loads and armour designed to defeat them can be far lighter and more flexible.Methods and subjects: Phase 1: Human performance in slash attacks: 87 randomly selected students at the Royal Military College of Science were asked to make one slash attack with an instrumented blade on a vertically mounted target. No instructions on how to slash the target were given. The direction, contact forces and velocity of each attack were recorded. Phase 2: Clinical experience with edged weapon attacks: The location and severity of all penetrating injuries in patients attending the Glasgow Royal Infirmary between 1993 and 1996 were charted on anatomical figures.Results Phase 1: Two types of human slash behaviour were evident: a ‘chop and drag’ blow and a ‘sweep motion’ type of attack. ‘Chop and drag’ attacks had higher peak forces and velocities than sweep attacks. Shoulder to waist blows (diagonal) accounted for 82% of attacks, 71% of attackers used a long diagonal slash with an average cut length of 34 cm and 11% used short diagonal attacks with an average cut length of 25 cm. Only 18% of attackers slashed across the body (short horizontal); the average measured cut length of this type was 28 cm. The maximum peak force for the total sample population was 212 N; the maximum velocity was 14.88 m s−1. The 95 percentile force for the total sample population was 181 N and the velocity was 9.89 m s−1. Phase 2: 431 of the 500 patients had been wounded with edged weapons. The average number of wounds sustained by victims in knife assaults was 2.4. The distribution of wounds by frequency and severity are presented.Conclusions Anti-slash protection is required for the arms, neck, shoulders, and thighs. The clinical experience of knife-attack victims provides information on the relative vulnerabilities of different regions of the body. It is anticipated that designing a tunic-type of Police uniform that is inherently stab and slash resistant will eventually replace the current obvious and often bulky extra protective vest. Attempts at making a combined garment will need to be guided by ergonomic considerations and field testing. A similar anatomical regional risk model might also be appropriate in the design of anti-ballistic armour and combined anti-ballistic and knife-resistant armour

Prospects of microalgal biodiesel production in Pakistan – a review

Biodiesel is an alternative, renewable, biodegradable and environmentally friendly fuel for transportation, with properties like petroleum-derived diesel, and can be used directly in a compression ignition engine without any modifications. The world's fossil fuel and crude oil reserves are going to dry up in the next few decades, but, contrariwise, an attractive, high quality, readily available and economically extractable oil from microalgae is a substitute feedstock to produce alternative biodiesel fuel for the transportation sector in the future. Microalgae have a higher biomass productivity (tons/hectare/year) and lipid yield (kg/kg of algal biomass) as compared to vegetable oil crops. To overcome the problem of energy deficiency in developing countries, like Pakistan, and boost their economic growth, alternative fuels are proving very important for environment-friendly and sustainable development, especially in the last few decades. Different research studies on microalgae cultivation, characterization of microalgae oil (lipids), and evaluations of its socio-economic feasibility to produce renewable biodiesel have been conducted in the past in Pakistan for its future prospects. This review paper includes the overall summary and compilation of the microalgae research conducted in Pakistan on biodiesel production and includes the algal biodiesel production cost analysis. The studies showed promising results for harnessing microalgae and using its lipids to produce biodiesel with favourable properties that were comparable to the conventional diesel in Pakistan. The information related to the microalgae research will help stakeholders and governmental organisations working in the renewable energy sector to consider its cultivation on a large scale, using waste water as a feedstock to produce biodiesel to meet the target set by the Government of Pakistan of using 10% blended biodiesel by the year 2025 in Pakistan

Mild pyrolysis of manually pressed and liquid nitrogen treated de‐lipid cake of nannochloropsis oculata for bioenergy utilisation

Due to the damaging impacts of continued use of fossil fuels, there is global interest in developing sustainable biofuel production to reduce society's dependency on carbon based energy resources. Microalgae cultivation can contribute to CO2 fixation from the atmosphere, while simultaneously producing a source of lipids from the biomass for third generation biodiesel fuel production. The residual de‐lipid cake left after lipid extraction can be treated with thermochemical techniques (such as mild pyrolysis) to produce solid biochar as an end product with a higher energy density and lower moisture content offering advantages for downstream processing or carbon sequestration. De‐lipid cake was produced by solvent extraction from Nannochloropsis oculata that had been manually pressed and/or treated with liquid nitrogen (LN2). The de‐lipid cake was thermally treated at 200 °C or 300 °C under partial vacuum in an oxygen free atmosphere. The solid biochar produced had a reduced moisture content (MC) resulting in a mass reduction of 25 and 66 wt % of de‐lipid cake without LN2 and treatment at 200 °C and 300 °C, respectively, while with LN2 treated cake the mass reduction was 23 and 67 wt % at 200 °C and 300 °C. The higher heating value of the control sample (without any manual pressing or LN2 treatment) was 23.35 MJ kg−1, while for the control sample it was enhanced to 26.82 and 30.56 MJ kg−1 with treatment at 200 °C and 300 °C, respectively. With LN2 treated samples with pressing the HHV was 21.98 MJ kg−1 for control sample as compared to 25.90 and 28.72 MJ kg−1 at 200 and 300 °C respectively, where the lower values were observed because of the lipid removal. The measured gas pressure developed, likely due to the production of CO2 and CH4 as major gases,, was 0.19 and 0.53 bars without LN2 treatment samples, while it was 0.13 and 0.58 bars with LN2. The torrefaction process (mild pyrolysis) energy analysis showed that the ER (energy ratio) without LN2 treatment sample with 0.485 at 200 °C was the highest and the lowest 0.407 energy ratio was found with LN2 treated sample at the higher treatment temperature (300 °C)

Possibility of converting indigenous Salvadora persica L. seed oil into biodiesel in Pakistan

In this research study, biodiesel has been successfully produced from vegetable seed oil of an indigenous plant Salvadora persica L. that meets the international biodiesel standard (ASTM D6751). The biodiesel yield was 1.57 g/5 g (31.4% by weight) and the in-situ transesterification ester content conversion was 97.7%. The produced biodiesel density was 0.894 g/mL, its kinematic viscosity 5.51 mm2/s, HHV 35.26 MJ/kg, flash point 210°C, cetane no. 61, and sulfur content 0.0844%. Thermal analysis of the biodiesel showed that 97% weight loss was achieved at 595°C with total oxidation of the biodiesel. The production energy efficiency was 0.46% with a lab scale setup, assuming the volume fraction ratio (volume of the sample/total volume of the equipment used). The results revealed that single-step in-situ transesterification method is suitable for the production of biodiesel from S. persica seed oil

microRNAs and Esophageal Cancer - Implications for Pathogenesis and Therapy

Author version made available in accordance with the publisher's policy.There are several microRNAs that have been consistently reported to be differentially expressed in esophageal squamous cell carcinoma vs. normal squamous tissue, with prognostic associations for miR-21 (invasion, positive nodes, decreased survival), miR-143 (disease recurrence, invasion depth), and miR-375 (inversely correlated with advanced stage, distant metastasis, poor overall survival, and disease-free survival). There is also evidence that miR-375 regulates gene expression associated with resistance to chemotherapy. Hence, microRNA expression assays have the potential to provide clinically relevant information about prognosis and potential response to chemotherapy in patients with esophageal squamous cell carcinoma. Results are inconsistent, however, for microRNAs across different studies for esophageal adenocarcinoma (EAC) vs. its precursor lesion Barrett’s esophagus. These inconsistencies may partly result from pathological and/or molecular heterogeneity in both Barrett’s esophagus and EAC, but may also result from differences in study designs or different choices of comparator tissues. Despite these inconsistencies, however, several mRNA/protein targets have been identified, the cancer related biology of some of these targets is well understood, and there are clinico-pathological associations for some of these mRNA targets. MicroRNAs also have potential for use in therapy for esophageal cancers. The development of new delivery methods, such as minicells and autologous microvesicles, and molecular modifications such as the addition of aromatic benzene pyridine analogs, have facilitated the exploration of the effects of therapeutic microRNAs in vivo. These approaches are producing encouraging results, with one technology in a phase I/IIa clinical trial

COX-2 mRNA is increased in oesophageal mucosal cells by a proton pump inhibitor

Author version made available in accordance with the publisher's policy.Introduction: Barrett’s oesophagus develops in some individuals with gastro-oesophageal reflux, and is the precursor to oesophageal adenocarcinoma. Proton pump inhibitors (PPIs) suppress gastric acid production and are used to treat reflux. Clinical trials suggest that COX inhibitors might prevent oesophageal cancer, although PPIs could offset this by increasing COX-2 expression in Barrett’s oesophagus. To investigate this, we evaluated the impact of a PPI on COX expression in oesophageal mucosal cells. Methods: The effect of the PPI esomeprazole on COX-1 and COX-2 mRNA levels in oesophageal cells was determined. Oesophageal cell lines OE33 (adenocarcinoma derived) and HET-1A (immortalized squamous cells), and a control intestinal cell line - HT29 (colon carcinoma), were treated for 24 hours with increasing concentrations of the esomeprazole. Results: COX-2, but not COX-1, mRNA levels, dose dependently increased in OE33 and HET-1A cells vs. esomeprazole concentration. COX-2 mRNA levels did not increase in HT29 cells. Conclusions: Exposure to esomeprazole increases COX-2 mRNA in oesophageal cells. This might contribute to the lack of benefit for COX inhibitors for oesophageal cancer prevention in recent clinica

Molecular biomarkers and ablative therapies for Barrett’s esophagus

Author version made available in accordance with the publisher's policy.Barrett’s esophagus is the major risk factor for esophageal adenocarcinoma. Endoscopic interventions which ablate Barrett’s esophagus mucosa lead to replacement with a new squamous (neosquamous) mucosa, but it can be difficult to achieve complete ablation. Knowing whether cancer is less likely to develop in neosquamous mucosa or residual Barrett’s esophagus after ablation is critical for determining the efficacy of treatment. This issue can be informed by assessing biomarkers that are associated with an increased risk of progression to adenocarcinoma. Although there are few post-ablation biomarker studies, evidence suggests that that neosquamous mucosa may have a reduced risk of adenocarcinoma in patients who have been treated for dysplasia or cancer, but some patients who do not have complete eradication of non-dysplastic Barrett’s esophagus may still be at risk. Biomarkers could be used to optimize endoscopic surveillance strategies following ablation, but this needs to be assessed by clinical studies and economic modeling

MEGASAT: automated inference of microsatellite genotypes from sequence data

MEGASAT is software that enables genotyping of microsatellite loci using next-generation sequencing data. Microsatellites are amplified in large multiplexes, and then sequenced in pooled amplicons. MEGASAT reads sequence files and automatically scores microsatellite genotypes. It uses fuzzy matches to allow for sequencing errors and applies decision rules to account for amplification artefacts, including nontarget amplification products, replication slippage during PCR (amplification stutter) and differential amplification of alleles. An important fea- ture of MEGASAT is the generation of histograms of the length–frequency distributions of amplification products for each locus and each individual. These histograms, analogous to electropherograms traditionally used to score microsatellite genotypes, enable rapid evaluation and editing of automatically scored genotypes. MEGASAT is written in Perl, runs on Windows, Mac OS X and Linux systems, and includes a simple graphical user interface. We demon- strate MEGASAT using data from guppy, Poecilia reticulata. We genotype 1024 guppies at 43 microsatellites per run on an Illumina MiSeq sequencer. We evaluated the accuracy of automatically called genotypes using two methods, based on pedigree and repeat genotyping data, and obtained estimates of mean genotyping error rates of 0.021 and 0.012. In both estimates, three loci accounted for a disproportionate fraction of genotyping errors; conversely, 26 loci were scored with 0–1 detected error (error rate ≤0.007). Our results show that with appropriate selection of loci, automated genotyping of microsatellite loci can be achieved with very high throughput, low genotyping error and very low genotyping costs