American Standards Research Articles

Tribological properties of copper (II) oxide nanoparticle-enriched sandbox bio-lubricant

The demand for bio-lubricant is constantly on the increase due to rapid depletion of world fossil fuel reserves, technological advancement, concern for environmental pollution and its potential to address the energy and environmental problems. This research evaluated the tribological properties of copper (II) oxide nanoparticle-enriched bio-lubricant developed from sandbox (Hura crepitans) seed oil. Copper (II) oxide nanoparticle was added to improve the tribological properties of the bio-lubricant. The experimental parameters were set up according to central composite design of response surface methodology to minimize the numbers of experiments. The bio-lubricants containing varying proportions of copper (II) oxide nanoparticle additive were prepared and their tribological properties were evaluated using ball-on-disc tribometer. The values of parameters used to assess the tribological behaviors were: load (2 N, 5 N, 8 N), speed (150 rpm, 200 rpm, 250 rpm) and nanoparticle concentration (0 wt%, 0.75 wt%, 1.50 wt%). The effects of these parameters on wear rate, friction coefficient and flash temperature parameter were evaluated. The lowest value of coefficient of friction (0.048) was obtained at a speed of 250 rpm and concentration of 0.75 % with load of 5 N. The lowest value of wear rate (0.012) was obtained with load of 5 N, speed of 200 rpm and concentration of 0.75 %. The highest value of flash temperature parameter (0.035) was obtained with load of 5 N, speed of 250 rpm and concentration of 0.75 %. The obtained values complied with the standard specified by American Standards and Testing Materials (ASTM) and compare favourably with conventional lubricant SAE 40 and other bio-lubricants. The results of the analysis were used for optimizing the parameters to obtain the best lubricant effects. The optimal combination of parameters for minimum coefficient of friction and wear rate as well as maximum flash temperature were found to be: 5.0909 N load, 217.6768 rpm speed and 1.1061 wt% concentration. The overall results revealed that enrichment of sandbox oil with copper (II) oxide nanoparticle improved the tribological behavior of the oil.

THE NEW SELFIE STANDARD: FACETUNE AND THE SHIFT TOWARD EAST ASIAN SELFIE AESTHETICS

Since its release in 2013, Facetune has risen to become the top paid photo and video app in the US. In this study, we document that the types of retouching tools Facetune make available mark a more significant shift in the American cultural practice of image editing, signaling an adoption of East Asian attitudes toward beauty standards and the plasticity of the image. Working within the Critical Technocultural Discourse Analysis (CTDA) framework, we track this shift by undertaking a Walkthrough Analysis of the Facetune app. This combination of methods allowed us to examine not only cultural beliefs around the self-image but also the affordances and materiality of the app by directly engaging the interface and technical functions of the app. We found evidence of Facetune pushing certain East Asian beauty ideals that may fall outside of American standards such as the Face resizing features that allow users to adjust nose, eyes, forehead, and lips by size and position. Furthermore, Facetune uses the photo not in its traditional role as a vessel for depicting a certain scene in time, but as a blank canvas on which to produce an ideal digital self. These findings offer a significant contribution in understanding shifting image editing practices online, particularly by highlighting the new technological tools and cultural beliefs that are leading this shift.

Local buckling behaviour and capacities of Cold-Formed Steel Double-I-Box stub and short column sections

This paper presents an experimental and numerical investigation on the local buckling behaviour of a new built-up Cold-Formed Steel (CFS) homogeneous and hybrid Double-I-Box Column sections (DIBCs and HDIBCs) under axial compression. In total, 24 experimental tests are conducted, out of those 12 tests are on stub columns and the remaining 12 are on short columns. The parameters considered are hybrid ratio (Φh), section’s breadth to depth ratio (B/D) and column height (H). The columns considered in this study are having an overall slenderness (λ) less than 0.20, and the flange plate slenderness (λpf) less than 1.85. Test specimens failed in either of the following three failure modes: local buckling, yielding or by the interaction of both. In all the tested specimens, typical Bottom Zone Local Buckling (BZLB) similar to the shape of Elephant’s Foot is identified. The deformation shape is recognized by expansion (outward buckling) along the major axis and contraction (inward buckling) along the minor axis at the bottom 1/4th height of the columns in opposite faces, followed by the collapse. This kind of failure mode is a clear representation of Poisson’s ratio effect at the ends causing a restraint which then creates a local imperfection under load which leads to a localized failure at bottom zones in the stub and short columns of DIBCs and HDIBCs. BZLB phenomenon is enhanced because of the tubular cross-section geometry, boundary conditions plate element slenderness, overall slenderness of these built-up sections. The ultimate capacities of both the stub and short columns are governed by their strength limits and slenderness. Nonlinear Finite Element Analysis (FEA) is performed on experimental FE models using ABAQUS software and verified against the test results and validated with the actual structural behaviour. Further FEA is performed on 96 ideal parametric FE models considering different material properties and slenderness values. Effect of the intermediate longitudinal stiffener and the influence of edge constraints on axial strengths are also reported. The axial strengths obtained from the experimental tests and FE parametric studies are compared with the predicted results using the Effective Width Method (EWM) as suggested in the Eurocode specifications to access the feasibility of the current design rules, which is found to produce reasonable predictions albeit slightly conservative. It is found that for stub columns with λ<0.1, the experimental values are found to be 1.25 times higher than the predicted values. It is also observed that for columns having λ≥0.1<0.2 with λpf>1.2 there is a reduction in local buckling resistance of around 2.5% for each increase of λpf by 10%. Hence, it is concluded that the concentric axial compression capacities of DIBCs and HDIBCs subjected to local buckling can be computed as the arithmetic summation of effective strengths of individual channel sections calculated by using the EWM design equations, as recommended in this study. The attained results prove that these sections have a considerable local inelastic reserve strength as specified in North American standards.

Whistle-blowers, Wokeness and the CIA

The CIA has developed an uneasy relationship with the American people, who regard it alternately as suspect and protective. Whistle-blowers and turncoats have tended to expose its ethical shortcomings, and sometimes have wilfully impaired US national security in doing so. But the agency stood tall in 2019, when a CIA analyst reported then-president Donald Trump's impeachable improprieties to intelligence-community overseers. Of late, the CIA has also manifested its recognition of the need for the organisation to better embody evolving American standards and mores, including diversity. A recent recruitment video was self-consciously and comically ‘woke’, and drew wide ridicule. That particular effort may have been maladroit. But the CIA is generally right to try to minimise the sociopolitical reasons for avoidable complaints among its officers and overseers so that they can devote maximum attention to the formidable security challenges facing the nation.

Behavior of geopolymer concrete‐filled circular steel tube members

AbstractBehavior of geopolymer concrete‐filled circular steel tube members was experimentally investigated. Four column specimens and one beam specimen were prepared using fly‐ash based geopolymer concrete. The material properties for both circular steel tubes and the geopolymer concrete infill were measured. The column specimens were tested under concentric and eccentric compression while the beam specimen was tested under three‐pointing bending, aiming to investigate the behavior of the structures subject to compression or combined loading. The load‐deformation behavior, compressive and bending strengths and failure mode of the specimens observed through the experiments are also reported in this paper. The compressive load and moment interaction relationship was developed using the experimental results. The measured ultimate compressive loads and ultimate moment capacity were also compared with the predictions obtained based on European and American Standards. It shows through the comparison that the predictions based on the standards are conservative. Therefore, the European and American Standards can be applied to safely design the structures.

Long term exposure to low level air pollution and mortality in eight European cohorts within the ELAPSE project: pooled analysis

ObjectiveTo investigate the associations between air pollution and mortality, focusing on associations below current European Union, United States, and World Health Organization standards and guidelines.DesignPooled analysis of eight cohorts.SettingMulticentre project...

Finite element analysis and design of retrofitted beam-to-column joints with welded haunches

This paper presents numerical investigations on the design of beam-to-column joints retrofitted by welded haunches. Finite element models (FEMs) were developed and validated against experimental results. A FE parametric study was then conducted concerning some critical characteristics, including the axial column load, haunch height, and haunch dip angle. The numerical results generated herein were utilised to evaluate the moment resistance given by the European, American, Japanese, and Chinese standards and the elastic rotational stiffness provided by the European and Japanese standards. Results showed that the improved moment resistance of enlarged panel zones depended mainly on the haunch height and axial column compression. The reversal of the shear force in shear plates would be more significant following the increase of haunch dip angles and the decrease of haunch heights. Although welded haunches reinforced both the panel zone and the beam, the yielding of joint assemblies was still dominated by the yielding of panel zones. Moreover, the Eurocode overestimated the elastic rotational stiffness by 16.1%–25.1%, and the Chinese standard overestimated the resistance by 12.6%–33.1%. In contrast, predictions by the Japanese code agreed well with FE results. The design methods were proposed based on the parametric analyses and comparisons, including the recommended configurations, mechanical behaviour calculations, moment-rotation behavioural model, and checking procedures.

Brain trauma exposure for American tackle football players 5 to 9 and 9 to 14 years of age

American football helmets used by youth players are currently designed and tested to the same standards as professionals. The National Operating Committee on Standard and Safety requested research aiming at understanding the differences in brain trauma in youth American football for players aged five to nine and nine to fourteen years old to inform a youth specific American football standard. Video analysis and laboratory reconstructions of head impacts were undertaken to measure differences in head impact frequency, event types, and magnitudes of maximum principal strain (MPS) for the two age groups. Overall frequencies and frequencies for five categories of MPS representing different magnitudes of risk were tabulated. The MPS categories were very low (<0.08), low (0.08–0.169), medium (0.17–0.259), high (0.26–0.349) and very high (>0.35). Both cohorts experienced a majority of head impacts (>56%) at very low magnitude of MPS. Youth American football players aged 9–14 yrs. sustained a greater frequency of head impacts at MPS between 0.08 and 0.169 % associated with changes in brain structure and function. There were no differences in overall frequency, or in frequency of head impacts in other categories of MPS. The proportion of impacts considered injurious (MPS > 0.08) was greater in the 5–9 group (44%), than the 9–14 group (39%), and impacts above 0.35 % were only reported for the younger age group. The larger helmet-to-shoulder ratio in the younger age groups may have contributed to this finding suggesting that youth American football players under the age of nine would benefit from a child-specific football helmet.

PENGARUH CAMPURAN LIMBAH TUNGGAK KAYU TUMIH (Combretocarpus rotundatus (Miq) Danser) DAN LIMBAH KAYU GALAM (Melaleuca cajuputi) TERHADAP KARAKTERISTIK BRIKET ARANG DARI KAYU KHAS LAHAN BASAH DI KALIMANTAN SELATAN

Tumih (Combretocarpus rotundatus (Miq.) Danser) and Galam (Melaleuca cajuputi) are typical vegetation of the wetlands of South Kalimantan. Tumih and galam wood waste can be made into charcoal briquettes which have economic value. The aims of this study were: 1) Analyzing the characteristics of charcoal briquettes, namely: water content, density, ash content, volatile matter content, bound carbon content and calorific value and 2) Knowing the best treatment from a variety of treatments. The design model used was a completely randomized design (CRD) with 4 treatments and 3 replications. The process of making charcoal briquettes at the Forest Products Technology Laboratory. Testing the characteristics of charcoal briquettes was done at the Laboratory of the Research and Industrial Standardization Institute (BARISTAND) Banjarbaru. The results of the analysis of diversity showed that the mixed treatment of tumih wood waste and galam wood waste had a very significant effect on water content, ash content, volatile matter content, bound carbon content and calorific value, but had no significant effect on density. The water content of charcoal briquettes from galam wood waste and tumih wood waste and the combination of a mixture of galam wood waste and tumih wood waste ranged from 6.1133-10.6667 %, the average density value was between 0.5228-0.5897 g/cm3, the average value The average ash content is between 1.3000-2.9300%, the volatile matter content shows an average range of 41.6333-48.4767%, the average value of bound carbon content is 37.9267-50.5400% and the average calorific value ranged from 5084.41 to 6230.59 cal/g. Treatment A3 (25% galam wood waste + 75% tumih wood waste is the best treatment and meets American standards for moisture content and calorific value. Ash content of all treatments are A1. A2, A3 and A4 meet American standards.

Effective stiffness and period-dependent seismic response modification factors for flexure-dominated fully-grouted reinforced masonry rectangular shear walls

The wall effective elastic stiffness, displacement ductility, and seismic force modification factors are important force-based seismic design (FBD) parameters for reinforced masonry (RM) shear walls. The effective stiffness, ke of reinforced masonry shear walls (RMSW) is crucial in computing the natural period and thus the elastic forces, and essential also in computing the displacements corresponding to the design seismic forces. This study analyzes previously reported test results of forty-three flexure-dominated fully-grouted rectangular RMSWs subjected to quasi-static cyclic load to evaluate the FBD parameters adopted by Canadian and American standards. In this study, based on the experimental results of 43 tested walls, a new stiffness reduction factor is proposed considering the effect of axial stress, vertical reinforcement ratio, and horizontal reinforcement ratio. Moreover, the seismic force modification factors are compared to the Canadian and US codes. The results showed that ductility related reduction factors should be dependent on the wall natural frequency and there is a room to relax the current proposed code values. In addition, incremental dynamic analysis was performed using a simplified numerical model to study the effect of dynamic loading on response modification factors and stiffness characteristics of the walls.

Bioprospecting wild South African microalgae as a potential third-generation biofuel feedstock, biological carbon-capture agent and for nutraceutical applications

Microalgae are among the few biological resources studied that are found to possess vast biotechnological potential. This study isolated, identified and investigated two wild green microalgal species with substantial potential as a bioresource and climate change mitigation importance. Two isolates, Chlorella sorokiniana and Tetradesmus reginae were cultivated in selected artificial media under laboratory conditions. The isolates were analysed for nutrient consumption, biomass productivity, CO2 biosequestration rate, elemental composition and fatty acid methyl profiles/composition. The outcome showed maximum daily biomass productivity of 0.128 ± 0.003 and 0.2 ± 0.004 g L−1 for C. sorokiniana and T. reginae, respectively. CO2 biosequestration rate of T. reginae was the highest among the isolates, indicating that it can act as a biological climate change mitigation agent. Moreover, T. reginae recorded a significantly higher (p < 0.05) total lipid and carbohydrate content than C. sorokiniana. The C/N ratio for T. reginae was significantly higher than the C/N ratio for C. sorokiniana. Tetradesmus reginae also demonstrated the ability to produce a considerable quantity of omega-3 oils; hence, the species is of nutraceutical importance. Furthermore, T. reginae demonstrated maximal carbohydrate content and is therefore considered a potential feedstock for bioethanol production. Chlorella sorokiniana, on the other hand, showed a remarkable (p < 0.05) protein content making it a potential source for human food and animal feed supplement. Finally, the two isolates met both European and American quality biodiesel standards with exceptional cetane (CN) and iodine numbers (IV).

Residual compressive stress–strain relationship of lightweight aggregate concrete after exposure to elevated temperatures

This experimental study investigated the compressive behavior of lightweight concrete after exposure to elevated temperatures. In total, 240 samples from 30 different mixtures were prepared and tested to evaluate the compressive strength, elastic modulus, strain at peak stress, and stress–strain relationships of lightweight aggregate concrete (LWAC) after being exposed to elevated temperature of 250, 500, and 750 °C. Test variables were composed of cement content varied between 300 and 700 kg/m3, volumetric percentage of lightweight expanded clay aggregates (Leca) substituting natural sand and gravel at 0, 25, 50, 75, and 100% (by weight), silica fume replacing cement at 5, 7.5, 10, 12.5, and 15% (by weight) and different water to cement ratios of 0.250, 0.313, 0.375, 0.438, and 0.500. The compressive strength, elastic modulus, and strain in the maximum stress were compared with predictions from the American and European standards and the proposed analytical models. The results showed that the compressive strength and elastic modulus of LWAC declined with increasing the temperature. The samples S6, S4 and S23 performed better compared to other specimens at elevated temperature as they retained about 96%, 75% and 42% of compressive strength, respectively after exposure to 250, 500 and 750 °C. A higher residual compressive strength was observed in the sample including 75% Leca at 750 °C. The experimental stress–strain relationship was verified according to the available analytical models and an analytical model was proposed to estimate the compressive behavior of LWAC at elevated temperature.

Impact of mixing and curing temperatures on fresh and hardened states’ properties of UHPC

New Canadian and American standards for concrete and bridges now provide guidelines for the design, production, curing, material characterization, and installation of ultra-high performance fiber reinforced concretes (named UHPFRC or UHPC) on structures. However, some technical aspects require more research since fundamental knowledge about UHPC is not as complete as for normal strength concretes (NSC). Among these aspects, knowledge on the properties of UHPC produced under field conditions is scarce. The main goal of this work was to evaluate the fresh state properties (slump flow, air content, mass density, hydration heat) and hardened state properties (elastic modulus, Poisson ratio, compressive and flexural strengths) of a UHPC subjected to various mixing temperatures (10, 20, and 30 °C) and curing temperatures (10, 23, and 35 °C) encountered in field conditions. The impact of mixing and curing temperatures on each property is discussed and practical information is provided to help engineers planning UHPC curing duration and formwork stripping.

Physical Fitness of Women From Biała Podlaska Aged 60 or Older

Abstract Introduction The ongoing process of aging in the Polish society generates the necessity to take interest in the problems and needs of the elderly population. Age-appropriate fitness is an important factor contributing to an optimal level of seniors’ life quality and maintaining their independence in everyday life. The aim of this research was to evaluate the level of physical fitness of elderly women from Biała Podlaska with respect to their age and body build. Material and Methods The research included 38 women attending activities in culture centers in Biała Podlaska. Measurements of basic somatic parameters were used to evaluate their body build on the basis of BMI. The Fullerton Test was applied to determine the level of physical fitness. Results In all trials of the Fullerton tests, most of the seniors achieved normal or above normal results. Statistically significant correlations were found between BMI and the test results in most trials. Correlations between age and test results were observed only in the endurance test. Conclusions The female respondents present a high level of physical fitness in relation to American standards. Due to the high percentage of respondents with excessive body weight, there is a need to develop relevant physical activity programs for this age group of women.

Cultivation of microalgae on unhydrolysed waste molasses syrup using mass cultivation strategy for improved biodiesel.

The online version contains supplementary material available at 10.1007/s13205-021-02823-7.

Spindle Error Movements and Their Measurement

The spindle of a machine tool is an important component of the machine. Its condition affects not only operation of the machine tool but also, above all, the quality of the workpiece. This paper explains the terminology and describes the research methods used to measure the spindle error movements of cutting machine tools. This article explains the impact of spindle motion inaccuracies on the quality of workpieces, quotes the requirements of European and American standards, and describes the current state and directions of development of the presented methods. Our own research work in this field is also presented.

Synthesis and structural characterization of energy crop peelu methyl esters, using hybrid metallic nano-particles. A step forward to bioenergy industry

In the present research project, the energy crop peelu non-edible oil was investigated as a potential source for fatty acid methyl esters production, using hybrid metallic nano-particles. The energy crop peelu is an evergreen shrubby plant distributed throughout the tropical and subtropical regions of the world. Naturally, the plant has having a worthy fates masses, had proceeded an optimum results for quantitative and qualitative methyl esters production, using hybrid metallic nano-particles poly-N-isopropylacrylamide “PNIPAM-Cu, PNIPAM-Pd & PNIPAM-Cu@Pd”. Whereas, the carboxyl functionalized P(NIPAM) microgels was synthesized via soap free emulsion polymerization, containing poly-N-isopropyl acrylamide and acrylic acid. The proposed thiol group was then introduced via carbodiimide mediated imide bond between the carboxyl group of carboxyl functionalized microgels and the amine from amino-ethanethiol. The Copper, Palladium and Copper@Palladium nano-particles were mixed-up into thiol-functionalized Poly-N-isopropylacrylamide microgels through metals thiol linkage. The hybrid metallic nano-particles were characterized using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) & Fourier Transfer Infra-Red (FT-IR) for rectification. The experimentation protocol for methyl esters synthesis using various concentrations of hybrid metallic nano-particles in conversion was adjusted to 1:6 oil to methanol molar ratio, temperature 60 °C and reaction time 2 h and stirring 600 rpm, respectively. The optimum yield of methyl esters was reported 92.20 against 1.5gm PNIPAM-Cu@Pd nano-particle. The chemical and structural status of synthesized methyl esters were characterized by Gas Chromatography & Mass Spectroscopy (GC&MS), FT-IR & Nuclear Magnetic Resonance) NMR spectroscopes. The physico-chemical properties of peelu crop methyl esters were analyzed, checked and compared with the international American Standards for Testing Materials (ASTM) & European Union (EN) standards, accordingly.

Assessment of Gypsum And Limestone Rocks from Fat’ha Formation (m. Miocene) for Making Wallboard in The Makhmur Area – Northern Iraq

Five samples of gypsum and one sample of limestone were collected from an outcrop in Qara Chugh Anticline. The samples of gypsum were analyzed chemically before and after calcination. The purity of the samples of gypsum and limestone was calculated and the (H2O+) content of the calcined samples of gypsum was determined. The physical and mechanical properties of plaster of Paris produced from calcining the samples of gypsum were tested according to the Iraqi and American Standards. A wallboard sample was made using basic materials according to the American Standard. The chemical analyses of the samples of gypsum and plaster of Paris conform to the Iraqi and American Standards. The Fat'ha Formation rocks in the Makhmur area are suitable for making wallboard. The optimum conditions for calcining the studied gypsum rocks to produce plaster of Paris conforming to the standard specifications and suitable for the manufacture of wallboard are 130 °C for 1 hour.

Skeleto-dental features among a sample of Saudi female children compared to North American standards: A cephalometric study.

This cross-sectional observational retrospective study aimed at assessing the cephalometric skeleto-dental features of class I, II, and III skeletal relationships of Saudi female school children samples and comparing the results to the established North American Caucasian cephalometric standards. The sample consisted of 205 retrospective lateral cephalometric radiographs of female school children. The age range of the subjects was between 10 and 13 years with a mean age of 11 ± 1 years. Several cephalometric and constructed points were identified. Angular, linear, and proportional measurements were obtained and analyzed. The skeleto-dental features of class II and class III were compared to class I of this sample then compared with the established North American Caucasian population. Different angular, linear, and proportional variables were investigated. Descriptive statistics and student t-test were used for data analysis. The distribution of the skeletal relationship revealed that 68.3% of the sample showed class I relationship, 16.1% class II, and 15.6% class III. The result indicates significant differences between the different classes. A greater tendency towards class II facial pattern and more convex profile among Saudis were detected in the present study compared to Caucasians. Furthermore, The dentoalveolar relationship results showed more Bi-maxillary protrusion among Saudi females compared to the North American Caucasians. The results obtained can be of great value in distinguishing the various skeleto-dental features in the different skeletal classes among the Saudi females and in the clinical diagnosis and treatment planning. Furthermore, the results of the study can also serve as a base-line for future investigations in Saudi Arabia.

STUDY TO MICROSTRUCTURE AND MECHANICAL PROPERTIES OF Mg-Zn-Fe-Cu-Co AS HIGH ENTROPY ALLOYS FOR URETERAL IMPLANT APPLICATION

Magnesium and its alloys are promising candidates for degradable materials with good biocompatibility. Alloys based on Mg-Zn-Fe-Cu-Co compositions were designed using the equiatomic method of high entropy alloy. This paper discusses the microstructure and mechanical properties of these new high entropy alloys. Pure Magnesium (60 µm), Zinc (45 µm), Fe (10 µm), Cu (63 µm), and Co (1 µm) powder were mixed and milled using a shaker mill at 700 rpm for the 1800s. The resulting milled powders were compacted and sintered at 300 MPa for 180s and 600 MPa for 120s. Sintering was performed at 700oC for 2 hours in a tube vacuum furnace at a 5 °C/min heating rate under a high purity argon atmosphere. Microstructural analyses and mechanical tests were performed based on the American standard of testing and measurement. The alloys were basically multiphase and crystalline. The 20Mg-20Zn-20Fe-20Cu-20Co alloy consisted of the HCP phase and cubic phase. The physical and mechanical properties of Mg-Zn-Fe-Cu-Co were affected by the magnesium content in the matrix alloys. The presence of pores indicated uncomplete compaction and sintering process. The alloys have a medium hardness of between 286.06 HV - 80.98 HV, while the densities of the alloys were relatively moderate in the range of 3.057 g.cm-3 to 1.71 g.cm-3. Solid solution and intermetallic precipitation strengthening were believed the primary strengthening mechanics of the alloys. It is concluded that high entropy is a promising method for the processing of Mg alloys. Alloy with a chemical composition of 20Mg-20Zn-20Fe-20Cu-20Co had optimal mechanical properties that meet the minimum requirements of high entropy alloys as candidates for ureteral implant applications.