Effect of the Type of Lateritic Soil on the Effectiveness of Geomechanical Improvement Using a Low Quantity of Cement for Sustainable Road Construction.

In Burkina Faso, the most commonly used road construction material is lateritic soil. However, in its raw state, this soil does not meet the required recommendations. To overcome this problem, previous studies have often focused on improving these soils by adding cement. However, these studies have rarely included a multi-criteria characterisation of the main geomechanical parameters of treated soils. It was also noted that the identification parameters of lateritic soils could have an influence on their improvement with cement. The aim of this study is to highlight the influence of the physical and mineralogical properties of lateritic soils on the effectiveness of improving their geomechanical properties by adding a low content of cement (<3% wt.). The soils were taken from two sites: Saaba (LAS) and Kamboinsé (LAK). The effects of cement addition on the plasticity index, CBR index, Young's modulus, unconfined compressive strength, tensile strength and shear strength were studied. In their raw state, LAS and LAK have different physical properties and cannot be used as sub-bases. The addition of cement improves the overall physical and mechanical properties of both soils, but to different degrees. Indeed, after adding 3% cement to the raw soils, the CBR index of LAS increases by 1275% compared with 257% for LAK; the unconfined compressive strength of LAS is twice as high as that of LAK, and the Young's modulus increases by around 460% for LAS compared with 360% for LAK. After improvement, these two soils met all the CEBTP specifications except for tensile strength. The effect of cement was more significant on LAS due to its better physical properties and higher clay mineral content, which would improve pozzolanic reactivity during cement hydration. Knowing the mineralogy of lateritic soils when treating them with cement would allow us to reduce the quantity of cement, thereby mitigating its negative impact on the environment.

Quality of Fine Yarns from Modacrylic/Polyacrylate/Lyocell Blends Intended for Affordable Flame-Resistant Underwear.

Flammability testing of undergarments is a topic that is often overlooked and rarely on the list of textiles to be tested for fire safety. However, it is particularly important for professionals exposed to fire risk to investigate the flammability of underwear as its direct contact with the skin can be critical to the extent and degree of skin burns. This research focuses on the suitability of affordable blends of 55 wt.% modacrylic, 15 wt.% polyacrylate, and 30 wt.% lyocell fibres that have the potential to be used for flame-resistant underwear. The influence of modacrylic fibre linear density (standard and microfibres), ring spinning processes (conventional, Sirospun, and compact), and knitted structure (plain, 2:1 rib, 2:1 tuck rib, single pique, and triple tuck) on their properties required for thermal comfort in high-temperature environments was investigated. Scanning electron and optical microscopy, FT-IR spectroscopy, mechanical testing, moisture regain, water sorption, wettability, absorption, DSC, TGA, and flammability were tested to assess the desired suitability. The wetting time (5-14.6 s) and water absorption time (4.6-21.4 s) of the knitted fabrics have shown excellent ability to transport and absorb water compared to the knitted fabrics created from a conventional blend of 65% modacrylic and 35% cotton fibres. The afterflame and afterglow times of less than 2 s met the criteria for non-flammability of the knitted fabrics according to the limited flame spread test method. The results show that the investigated blends have the potential to be used for affordable flame-retardant and thermally comfortable knitted fabrics for underwear.

The role of base-layer cooling conditions in human error occurrences during doffing of personal protective equipment in health care.

This study compared error rates during the personal protective equipment (PPE) removal process under different base-layer cooling conditions while performing the doffing procedures. Ten participants were recruited and received training on the standard doffing procedures before participating in the experiments. The participants were randomly assigned to one of the three base-layer conditions and ran on a treadmill for 30 min. Their physiological biometrics were monitored during exercise trials, and error rates were calculated. The results revealed a significant difference in error rates when PPE was worn over base-layer scrubs made of a cooling fabric versus when it was worn over the conventional medical scrubs. Further, there was a strong negative relationship between the body coverage amount with the cooling fabric and error rates occurring during the doffing procedures. Findings suggested practical considerations for the operational monitoring system and improved PPE design to avoid unintentional errors during the doffing procedures.

An Essential Role of Gelatin in the Formation Process of Curling in Long Historical Photos.

Curling disease in long historical photos significantly affects the presentation of cultural heritage information. However, people lack attention to the formation process and microstructural changes of photo curling. In this article, a long historical photo (1912-1949 AD) collected by the Second Historical Archives of China was taken as the research object, and the formation process and cause of the curling were further explored. Firstly, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray energy disperse spectrometer (EDS), and other instruments were used to analyze the material composition of the long historical photo. It was found that the photographic paper was made of gelatin, barium sulfate, and plant fiber layers. Then, the effects of hygrothermal environments on curling and contraction in the gelatin layer and simulated photographic paper were explored. Meanwhile, the formation process and main influence factors of the curling were preliminarily revealed. The morphological analysis by SEM was carried out to identify the inner correlation between the microstructure and curling of photos. Finally, the possible formation cause of photo curling was analyzed. This study provides a scientific basis and experimental data for the preservation and restoration of long historical photos based on gelatin.

Amine/phenyl gradient derived base layer as a comprehensive extractive phase for headspace cooled in-tube microextraction of volatile organic compounds in saliva.

A gradient derived base layer extractive phase was synthesized and applied for the determination of volatile organic compounds (VOCs) in saliva samples using the headspace cooled in-tube microextraction (HS-CITME) method. The base layers from three different sols of phenyltriethoxysilane (PTES), octyltrimethoxysilane (OTMS) and methyltrimethoxysilane (MTMS) as nonpolar precursors were individually dip coated on the stainless steel wires (SSW). Then, the hydrolyzed polar precursor aminopropyltriethoxysilane (APTES) reacted with the silanol groups already formed on the surface of SSWs via controlled rate infusion (CRI) method. The presence of polar and non-polar functional groups on the surface of substrate was evaluated by Fourier-transform infrared spectroscopy (FTIR) while the morphology and thickness of the most suitable gradient coating (amine/phenyl) were also investigated by scanning electron microscopy (SEM). Assessment of the gradient extractive phase efficiency was carried out determining a group of VOCs with different polarities coupled with gas chromatography-mass spectrometry (GCMS) and the improved performance of the synthesized base layer coatings was observed. Furthermore, a cooling device was designed and implemented to the extracting system to improve the efficiency by influencing the exothermic nature of process. The data were analyzed by principal component analysis (PCA), and hierarchical cluster analysis (HCA) and the results were interpreted by polarities of analytes. Finally, under the optimized conditions, the limits of detection (LOD) and limits of quantification (LOQ) were 0.15 and 0.50 ng L-1, respectively. The intra-day and inter-day relative standard deviations (RSDs) at 5 and 50 ng L-1 (n = 3) using a single extractive phase were 2-6 and 10-17, respectively. The data associated with RSDs% for three extractive phases were between 16 and 19 %. Eventually, the method was conveniently applied to the extraction of VOCs from saliva samples of smokers and satisfactory relative recoveries (RR%) (95-108 %) were achieved and low quantities of VOCs were detected.

Effects of Portland Cement and Polymer Powder on the Properties of Cement-Bound Road Base Mixtures.

This article presents the test results for the physical and mechanical properties and fracture toughness of polymer-modified hydraulically-bound mixtures (HBM) produced with Portland cement for road base layers. The modifier used was a redispersible polymer powder (RPP) based on a vinyl ethylene acetate (EVA) copolymer obtained by spray drying. A three-level full factorial design with two factors was applied to determine the contents of Portland cement and polymer powder in the cement-bound mixture (CBM). Both Portland cement and polymer powder were added at three levels: 0%, 2%, and 4%. The assessment included basic physical properties (water absorption, density, and bulk density) and mechanical properties (stiffness modulus, axial compressive strength, and indirect tensile strength) of the CBM. Particular attention was paid to the assessment of fracture toughness in the semi-circular bending test. The results of the research show that polymer powder positively influenced the mechanical properties of CBM by improving its cohesion while maintaining its stiffness. Another benefit coming from the use of polymer powder was the CBM's increased resistance to cracking, which is the desired characteristic from the perspective of pavement durability.

Influence of Clogging and Unbound Base Layer Properties on Pervious Concrete Drainage Characteristics.

This paper aims to assess the influence of clogging on paving material (pervious concrete) drainage characteristics as well as the influence of the properties of an unbound base layer on drainage characteristics of the whole paving system. The clogging influence has been studied measuring the drainage characteristics on pervious concrete flags before and after their clogging, according to ASTM C1701-09. Additionally, the drainage characteristics of uncontaminated pervious concrete as a paving material was assessed using the falling head method. To assess the influence of properties of an unbound base course (UBC) on drainage characteristics of the whole paving system, the unbound base layer was compacted in two different levels of compaction and the drainage characteristics were measured (according to ASTM C1701-09). It is concluded that pervious concrete prepared with a smaller aggregate fraction is more prone to clogging. Regarding the influence of UBC, it is important to find a balance between pervious concrete infiltration and UBC exfiltration rate, particularly in a case of pervious concrete flags made of coarse aggregate.

Stiffness Identification of Foamed Asphalt Mixtures with Cement, Evaluated in Laboratory and In Situ in Road Pavements.

The article presents the possibilities of using foamed asphalt in the recycling process to produce the base layer of road pavement constructions in Polish conditions. Foamed asphalt was combined with reclaimed asphalt pavement (RAP) and hydraulic binder (cement). Foamed asphalt mixtures with cement (FAC) were made, based on these ingredients. To reduce stiffness and cracking in the base layer, foamed asphalt (FA) was additionally used in the analyzed mixes containing cement. The laboratory analyzes allowed to estimate the stiffness and fatigue durability of the conglomerate. In the experimental section, measurements of deflections are made, modules of pavement layers are calculated, and their fatigue durability is determined. As a result of the research, new fatigue criteria for FAC mixtures and correlation factors of stiffness modules and fatigue durability in situ with the results of laboratory tests are developed. It is anticipated that FAC recycling technology will provide durable and safe road pavements.

Clinical value of new rapid pathological diagnosis technique in the examination of cervical lesions in primary medical institution / 中国基层医药

Objective To explore the clinical value of new rapid pathological diagnosis technology in the examination of cervical lesions in primary medical institution.Methods In the Affiliated Hospital of Yangzhou University,25 cases of cervical scraping and 22 cases of cerrical biopsy were selected.Twenty-five cases of cervical scraping scraped two wipers during operation,the results were compared with conventional pathological techniques and new rapid pathological diagnosis techniques.Twenty-two cases of cervical biopsy used a new rapid pathological diagnosis technique to perform cytological diagnosis of biopsy tissue rolls in biopsy operation.According to the results of rapid pathological diagnosis,the biopsy operation plan was adjusted to analyze the clinical value of the new rapid pathological diagnosis technique in cervical lesions in primary medical institution.Results The new rapid pathological diagnosis technology required less space and no pollution,and the diagnosis took about 2-3 min,which did not affect the normal inspection operation.Twenty-five cases of cervical scraping were produced with new rapid pathological diagnosis technique,and the quality of cervical scraping produced with conventional pathological technique was consistent,which could satisfy the needs of pathological cytological diagnosis;twenty-two cases of cervical biopsy under the vaginal device were assisted by this technology and it could increase the positive rate of the first biopsy.Conclusion Cervical scraping and cervical biopsy are still the main methods for cervical lesions examination in primary hospitals.The new rapid pathological diagnosis technology can provide the real-time pathological diagnosis of cervical scraping,improve the positive detection rate of the first biopsy of cervical biopsy,and the cost is low,suitable for promotion in primary medical institution.

Clinical value of new rapid pathological diagnosis technique in the examination of cervical lesions in primary medical institution / 中国基层医药

Objective@#To explore the clinical value of new rapid pathological diagnosis technology in the examination of cervical lesions in primary medical institution.@*Methods@#In the Affiliated Hospital of Yangzhou University, 25 cases of cervical scraping and 22 cases of cervical biopsy were selected.Twenty-five cases of cervical scraping scraped two wipers during operation, the results were compared with conventional pathological techniques and new rapid pathological diagnosis techniques.Twenty-two cases of cervical biopsy used a new rapid pathological diagnosis technique to perform cytological diagnosis of biopsy tissue rolls in biopsy operation.According to the results of rapid pathological diagnosis, the biopsy operation plan was adjusted to analyze the clinical value of the new rapid pathological diagnosis technique in cervical lesions in primary medical institution.@*Results@#The new rapid pathological diagnosis technology required less space and no pollution, and the diagnosis took about 2-3 min, which did not affect the normal inspection operation.Twenty-five cases of cervical scraping were produced with new rapid pathological diagnosis technique, and the quality of cervical scraping produced with conventional pathological technique was consistent, which could satisfy the needs of pathological cytological diagnosis; twenty-two cases of cervical biopsy under the vaginal device were assisted by this technology and it could increase the positive rate of the first biopsy.@*Conclusion@#Cervical scraping and cervical biopsy are still the main methods for cervical lesions examination in primary hospitals.The new rapid pathological diagnosis technology can provide the real-time pathological diagnosis of cervical scraping, improve the positive detection rate of the first biopsy of cervical biopsy, and the cost is low, suitable for promotion in primary medical institution.