Comparing the reinforcement capacity of welded steel mesh and a thin spray-on liner using large scale laboratory tests

Steel mesh is used as a passive skin confinement medium to supplement the active support provided by rock bolts for roof and rib control in underground coal mines. Thin spray-on liners(TSL) are believed to have the potential to take the place of steel mesh as the skin confinement medium in underground mines.To confirm this belief, large scale laboratory experiments were conducted to compare the behaviour of welded steel mesh and a TSL, when used in conjunction with rock bolts, in reinforcing strata with weak bedding planes and strata prone to guttering, two common rock conditions which exist in coal mines. It was found that while the peak load taken by the simulated rock mass with weak bedding planes acting as the control sample(no skin confinement) was 2494 kN, the corresponding value of the sample with 5 mm thick TSL reinforcement reached 2856 kN. The peak load of the steel mesh reinforced sample was only2321 kN, but this was attributed to the fact that one of the rock bolts broke during the test. The TSL reinforced sample had a similar post-yield behaviour as the steel mesh reinforced one. The results of the large scale guttering test indicated that a TSL is better than steel mesh in restricting rock movement and thus inhibiting the formation of gutters in the roof.

Preparation of composite poly(ether block amide)membrane for CO_2 capture

In this study, a poly（ether block amide） （Pebax 1657） composite membrane applied for COa capture was prepared by coating Pebax 1657 solution on polyacrylonitrile （PAN） ultrafiltration membrane. Ethanol/water mixture was used as the solvent of Pebax and the effects of ethanol/water mass ratios and Pebax concentration on the permeation properties of composite membrane were studied. To enhance the com- posite membrane permeance, the gutter layer, made from reactive amino silicone crosslinking with potydimethylsiloxane （PDMS）, was de- signed. The influence of crosslinldng degree of the gutter layer on membrane performance was investigated. As a result, a Pebardamino- PDMS/PAN multilayer membrane with hexane resistance was developed, showing CO2 permeance of 350 GPU and CO2/N2 selectivity over 50. The blend of polyethylene glycol dimethyl ether （PEG-DME） with Pebax as coating material was studied to further improve the membrane performance. After being combined with PEG-DME additive, CO2 permeance of the final Pebax-PEG-DME/amino-PDMS/PAN composite membrane reached 400 GPU above with CO2/Na selectivity over 65.

Numerical Analysis of Tilted Cutting and F128 Brushes

Road sweeping is an essential service that has to be conducted for public health,as well as aesthetic purposes.In many countries,sweeping vehicles are used for this activity.They usually comprise a gutter brush that sweeps the debris that is located in the road gutter.This work studies the performance of two kinds of gutter brushes:a cutting brush and a flicking(F128)brush.This is carried out by means of a 3-D dynamic,nonlinear Finite Element(FE)brush model developed by the authors.In this model,inertia forces are applied to the bristle,and its clamped end is fixed.Consequently,the surface(road)is rotated,translated,and raised.Bristle-road interaction is modelled as flexible-to-rigid contact.In particular,the aim of this article is to compare the performance of a conventional brush and a brush rotating at variable speed.As brushes normally work tilted,FE analyses are carried out for tilted cutting and F128 brushes,rotating at speeds that fluctuate at different frequencies.It is concluded that brush oscillations have a significant effect on bristle tip velocities and bristle-road forces.Also,at certain frequencies,oscillations seem to improve sweeping performance of the F128 brush.However,they do not appear to improve significantly the performance of the cutting brush.

Characterization and Application of the Makoua Clay in the Chemical and Bacteriological Depollution of Gutter and Well Waters of Brazzaville

In this work, the authors made aquatic filters according to the formulation “clay stabilized at 4% of cement mixed with 4% of kambala sawdust and 10% of white sand” then heated to 1050°C to decontaminate the waters of gutters and wells. The authors carried out geotechnical, geochemical, thermal, infrared spectroscopy, and scanning electron microscopy that analyzed the clay material. Geotechnical analyzes have shown that this material is made up of 22% thin sand, 22% of silt, and 56% of clay with 26 plasticity index. The geochemical analysis showed the presence of trace elements shared out as follows: 3% of alkaline metals, 24% of alkaline earth metals, 46% of transition metals, 10% of metal, 16% of lanthanides, 1% of actinides. The most abundant trace elements are barium (19%), vanadium (12%), chromium (11%) and zinc (9%). The thermal and microscopic analyzes revealed the kaolinitic nature of materials. The chemical depollution studies have shown elimination yields of 50% - 52.38% of sulphates;77.33% - 85.19% of phosphates;34.85% - 88.49% nitrates;91.3 - 100 of sulphides;The removal of bacteriological pollution are 92.8% - 98% of total germs;94% - 97% of total coliform and 95% - 98% of E. coli.

Total Peritoneal Gutter Removal versus Random Peritoneal Biopsy in Cases of Ovarian Cancer

Introduction: Ovarian cancer is the fourth most prevalent cancer among women and the seventh most common cancer overall. Every year, an estimated 200,000 cases and 125,000 deaths related to ovarian cancer are reported around the world. It is most common in high-resource countries, with an incidence rate of 9.3 per 100,000 women. Ovarian cancer is detected at an advanced stage in about 70% of instances, and only 30% of women with such cancers live for more than 5 years. Although only around 20% of ovarian cancers are limited to the ovaries at diagnosis, patients with localized disease have a 5-year survival rate of more than 90%. Peritonectomy is a crucial part of the surgical treatment for ovarian cancer. Visual inspection and palpation are not reliable methods for determining the extent of tumour involvement. The majority of gynecologic oncologists are suspicious about the benefits of a full peritonectomy, concerned about the benefits and hazards. They believe that the tumor’s fundamental biology, not surgical aggressiveness, dictates the tumor’s resectability. The aim of this work was primarily to compare the differences between total peritoneal gutter removal and random peritoneal biopsy in cases of early ovarian cancer. A secondary aim of this work is to show ability of total peritoneal gutter removal in relation to that of random peritoneal biopsy to detect positivity of metastasis in the histopathological specimens. Patients and Methods: This prospective cohort study was conducted on 130 patients with early ovarian cancer in El-Shatby hospital, Faculty of Medicine, Alexandria University. For each patient, we took random and total peritoneal biopsy and compared between them regarding technique, timing, post-operative complications, and histopathological results. Inclusion criteria: all age group, suspected ovarian cancer using IOTA score, absence of nodules in the peritoneal gutter using CT and any case that needs staging laparotomy for ovarian cancer. Exclusion criteria: presence of gross peritoneal disease in the gutter and CT features of advanced ovarian cancer (peritoneal deposits, omental cakes, pelvic and para-aortic lymphadenopathy). All cases will be subjected to the followings: history taking, clinical examination, suspicious ovarian mass using IOTA score, tumor markers, CT staging, staging laparotomy and random and total peritoneal biopsies will be collected from the same case and sent to the lab of pathology for histopathological examination and the results will be compred regarding positivity of metastasis. Results: Random peritoneal biopsy showed positive metastasis in 6 (4.6%) cases and free in 124 (95.4%) cases while total peritoneal gutter removal showed positive metastasis in 19 (14.6%) cases and free in 111 (85.4%) with Chi-square test was 7.479 and P value was 0.004 which is statistically significant. 108 (97.3%) cases had negative random peritoneal biopsy and negative total peritoneal gutter removal, 3 (2.7%) cases had positive random peritoneal biopsy and negative total peritoneal gutter removal, 16 (84.2%) cases had positive total peritoneal gutter removal and negative random peritoneal biopsy & 3 (15.8%) cases had positive total peritoneal gutter removal and positive random peritoneal biopsy with Chi-square test 6.311, FEp 0.04 and Kappa test 0.183 (0.012) which is statistically significant with poor strength of agreement. Conclusions: Modified total peritoneal gutter removal is a safe, fast and easy technique compared to random peritoneal biopsy and even to traditional peritonectomy procedure with high detection rates of peritoneal involvement with sensitivity of 50% and specificity of 87.5% and it is recommended to be done as a routine alternative to random peritoneal biopsy and even to traditional total gutter removal in all cases of ovarian malignancies for diagnostic and therapeutic values.