American Society Of Testing And Materials Research Articles

Influence of Choline Chloride/Urea and Glycerol Plasticizers on the Mechanical Properties of Thermoplastic Starch Plastics.

Bio-based plastics made of food-safe compostable materials, such as thermoplastic starch (TPS), can be designed into films that have potential to replace many non-biodegradable single-use plastic (SUP) items. TPS film characteristics, such as elongation at break and tensile strength, are largely affected by the choice of the plasticizers used in formulation. Our work identifies the mechanical properties and the chemical structural differences between TPS films made with two different plasticizer mixtures that have not yet been compared alongside one another: deep eutectic solvent choline chloride/urea (1:2) (CC:U) and glycerol with an acetic acid catalyst (AA:G). Potato-based TPS samples were formed by mixing each plasticizer with a consistent amount of potato starch and distilled water with heat. After gelation formation, the viscous TPS mixture was centrifuged to degas and extruded. Films were dried at controlled room temperature. Characterization included the tensile testing of coupons according to ASTM (American Society of Testing and Materials) standard D638, attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, X-ray diffraction (XRD), melting point (MP), and scanning electron microscopy (SEM). The AA:G films displayed significantly higher tensile strength (M = 2.04 ± 1.24 MPa) than the CC:U films (M = 0.18 ± 0.08 MPa); however, the CC:U films had higher elongation at break (M = 47.2 ± 3.6%) than the AA:G films (M = 31.1 ± 12.6%). This can be explained by the difference in functional groups, composition, and the degree of crystallinity evidenced by the FTIR, XRD, MP, and SEM results. Our findings suggest that potato-based TPS films with an AA:G plasticizer mixture hold promise for SUP applications that require more strength, while CC:U films may be more suited for wraps and bags that require flexibility. These innovations can aid to mitigate the environmental impact of harmful plastic waste.

Durability of clayey soil stabilized with calcium sulfoaluminate cement and polypropylene fiber under extreme environment

Calcium Sulfo-Aluminate Cement (CSAC) is gaining interest among researchers, consultants, engineers, and environmentalists as a prospective replacement of Ordinary Portland Cement (OPC) across many construction industries. The main reason is that the production of CSAC generates a lower carbon footprint as compared to OPC cement production. Other benefits of CSAC include quick bonding & strength development, and less shrinkage. Many studies are available and ongoing on the advantages and limitations of CSAC in concrete. However, only a few studies are available on its application in soil stabilization. Therefore, the efficiency of CSAC for soil stabilization is a topic of discussion in geotechnical engineering. In this research, a locally sourced highly compressible clayey soil was stabilized with different combinations of CSAC and polypropylene fiber (e.g., 5.0%, 7.5% & 10.0% of CSAC and 0.5% & 1.0% polypropylene fiber), and its effectiveness was observed and evaluated in terms of durability (Wetting-Drying and Freezing-Thawing tests) against extreme environments and also checked Unconfined Compressive Strength (UCS) as per American Society of Testing and Materials (ASTM) guidelines. The findings of this research are evaluated in terms of percentage of soil loss, change in moisture content and volume, and loss of strength after durability exposure. Moisture content and bulk unit weight were determined after each stage in the Freezing-Thawing durability cycles. Samples prepared with 10.0% of CSAC and 1.0% of fiber were able to survive all durability cycles of Wetting-Drying with PCA (Portland Cement Association) soil-loss percentage criteria. On the other hand, samples prepared with 10.0% cement with 0.5% as well as 1.0% fiber were able to survive all durability cycles of Freezing-Thawing with PCA soil-loss percentage criteria. These survived samples showed a significant amount of unconfined compressive strength even after being subjected to these durability cycles.

Improvement of Work-Hardening Behavior of Co-Cr-W-Ni Alloy by Adding Mn/Fe for Balloon-Expandable Stents

The Co-20Cr-15W-10Ni (CCWN, mass%) alloy, registered as American society of testing and materials (ASTM) F90, has been widely used as a balloon-expandable stent because of its excellent balance between its mechanical properties and corrosion resistance. To realize a less invasive stent placement, the stent diameter must be reduced, which implies that the stent strut thickness must be reduced. As such, the CCWN alloy must be high in strength and ductility while maintaining a low yield stress to facilitate the expansion and suppression of stent recoil. In this study, we focus on the effects of the adding Mn/Fe on the microstructure, mechanical properties, and corrosive properties of CCWN alloys. A 6 mass% Mn-added CCWN alloy with a grain size of approximately 20 μm prepared in this study exhibits excellent balance between tensile strength and ductility. In addition, it exhibits a lower yield stress while maintaining a high tensile strength compared with the ASTM F90 alloy. Meanwhile, a 6 mass% Fe-added CCWN alloy exhibits a higher ductility compared with the ASTM F90 alloy. The addition of Mn or Fe to the CCWN alloy increases the stacking fault energy of the alloy and suppresses strain-induced martensitic transformation during plastic deformation, thus improving the ductility of the alloy. Results of polarization tests show that the 6 mass% Mn-or Fe-added CCWN alloys exhibit the same corrosion current density as the ASTM F90 alloy. Mn-added Co-Cr-W-Ni alloys are suitable for use in balloon-expandable stents.

Development of cashew nut shell lignin-acrylonitrile butadiene styrene 3D printed core and industrial hemp/aluminized glass fiber epoxy biocomposite for morphing wing and unmanned aerial vehicle applications

The aim of this study was to develop a lightweight epoxy based biocomposite for morphing wing and unmanned aerial vehicle (UAV) applications. The proposed composite was developed using a 3D printed high stiffness lignin-Acrylonitrile Butadiene Styrene (ABS) core and industrial hemp with aluminized glass fiber epoxy skin. The ABS was reinforced using lignin macromolecule derived from cashew nut shells via twin screw extruder and the core was printed using an industrial grade 3D printer. Furthermore, the composites were prepared by compression moulding with an ABS-lignin core and hemp/aluminized GF surface and characterized according to respective American society of testing and materials (ASTM) standards. The findings indicate that the addition of 30 vol% Al-glass and hemp fiber with lignin strengthened ABS core improved the mechanical properties. The composite material designated as “E2” exhibits the maximum mechanical properties, providing tensile strength, flexural strength, Izod impact, interlaminar shear strength (ILSS), and compression values of, 136 MPa, 168 MPa, 4.82 kJ/m2, 21 MPa, and 155 MPa respectively. The maximal energy absorbed by composite designation “E2,” during drop load impact test is 20.6 J. Similarly, the composite designation “E2”gives fatigue life cycles of 33,709, 25,781 and 19,633 for 50 %, 70 % and 90 % of ultimate tensile strength (UTS) and 32.5 (K1c) MPa⋅m and 0.76 (G1c) MJ/m2 in fracture toughness and energy release rate respectively.

Extended fuel properties of sustainable aviation fuel blends derived from linalool and isoprene

Seven different sustainable aviation fuel blends were prepared with hydrocarbons derived from terpenoid precursors. The first, designated as L-Jet, was formulated with various molecules produced from linalool (a terpene alcohol) including hydrogenated methylcyclopentadiene dimers, p-menthane, 2,6-dimethyloctane, and hydrogenated isobutylene trimers. L-Jet was also blended with a synthetic paraffinic kerosene derived from fatty acids and esters (HEFA-Jet) as well as Jet-A. The other four sustainable aviation fuel blends consisted of either Jet-A or HEFA-Jet mixed with cyclic hydrogenated isoprene dimers that can be readily produced from the bio-based hemiterpene, isoprene. To determine the suitability of these blends as surrogates for conventional jet fuel, a number of properties including density, low temperature viscosity, heat of combustion, flashpoint, corrosion, smoke point, conductivity, simulated distillation, existent gum, lubricity, thermal stability, and derived cetane number were measured. The 100 % SAF blends exhibited higher gravimetric heats of combustion and higher smoke points (less soot) compared to the blends with Jet-A. Several of the blends met American Society of Testing and Materials (ASTM) requirements, suggesting that they are promising candidates for certification as next generation aviation fuels.

Integrating Fine Ceramic Tile Aggregates in Concrete Hollow Blocks

This study investigates the effect of fine ceramic tile aggregates (CTA), specifically floor and wall tiles, as a replacement for fine aggregates in non-load bearing Concrete Hollow Block’s (CHB) fresh and hardened properties. The experimental design of this study performed was in line with the American Society of Testing and Materials (ASTM) standard procedure. Results for the workability of CHB with CTA showed comparable behavior to the control mix, which ranged between low to medium slump values (49 mm-59 mm). Specimens with CTA are characterized by higher water absorption and lesser density and moisture content. All the CHB with CTA replacement yielded higher compressive strength than the control mix. The 30% CTA substitution gained the highest compressive strength of 3.20 MPa (462.12 psi) for 28-days of curing. Overall, the physical and mechanical qualities of the samples with CTA percentage performed better than the control mix.

Viability of Napier Grass Ash as Partial Substitute of Cement in CHB

The effects on the physical and mechanical properties of Napier grass ash (NGA) as substitute for ordinary Portland cement (OPC) on concrete hollow block (CHB) were investigated. Mix ratio of 1:2:4 with water-cement ratio of 0.60, and 10%, 15%, and 20% NGA replacements were adapted. Experimental procedures and testing conformed to American Society of Testing and Materials (ASTM) standards. Slump values, in comparison to control, showed a decline of 16.67%, 25%, and 58.33% for 10%, 15%, and 20% NGA replacements, respectively, which correlates to water absorption result. The denser the CHB, the lower the moisture content. Compressive strength results revealed that all NGA substitutes performed better than the control sample. NGA-20% had the highest compressive strength of 4.2 MPa (individual unit) and 3.9 MPa (average of 3 units) after 28 days of curing. Overall, NGA replacement was not viable for load-bearing but ideal for nonload-bearing CHB using the mix design.

A semi-industrial reactor for producing biodiesel from waste cooking oil

This work offers a pilot plant unit designed to produce biodiesel efficiently from waste cooking oil (WCO). The quality of biodiesel from the semi-industrial plant met American Society of Testing and Materials (ASTM) standards with a maximum yield of 71.56%. Many biodiesel samples were tested, but the highest yield was 71.56%, achieved with a mixing speed of 200 rpm, 20% methanol/oil ratio, reaction time of 90 min, reaction temperature of 70 °C, and catalyst concentration of 1%. The fatty acids in WCO were palmitic, oleic, and linoleic, 5.13, 37.22 and 7.66%, but for biodiesel they were 5.1, 26.16 and 49.51%, respectively. Thermal gravimetric analysis and Thin-layer chromatography confirmed the formation of biodiesel. The ester is in the range of 1741:2823 cm−1, which is related to the stretching band of C = O. The physicochemical properties agreed with ASTM standards. The biodiesel yield is significantly affected by the quality of the used WCO. The results indicate the significant effect of purity, quality, cooking temperature and cooking time of the used oil on biodiesel yield. A high yield of 94.5% was obtained for high-quality oil that was slightly heated for no cooking time. The designed pilot plant is efficient and reliable at producing biodiesel from WCO.

Approaches of material selection, alignment and methods of fabrication for natural fiber polymer composites: A review

The recent superiority of the composite materials is cautiously focusing on environmental adoption of natural fiber composites. The major source of the natural fiber materials covered in the globe, especially natural fibers, is plant-based, animal-based and mineral-based. Eco friendly based material can save the environment and recycling of the material is possible, as well as important criteria. Hence engineers ultimately focused on natural fiber polymer matrix materials to save the environment, pollution control, plastic manipulation, etc. The literature work was studied to identify natural fiber material possession. The major goal of the present review was to identify material characterization and appropriate application, mainly offering to enhance mechanical properties, flexural strength, electrical properties, thermal properties etc. The major consequence of the natural fiber is hydrophilic treatment. There is poor interfacial adhesion between the addition/filling substances and poor mechanical characteristics. All of these shortcomings constitute a critical issue. This review presents numerous sorts of natural and synthetic polymers, natural fibres such as jute, ramie, banana, pineapple leaf fibre, and kenaf, etc.; short and long fibre loading methods, fibre fillers in micro and nanoparticle, American society of testing and materials (ASTM) standard plate dimensions, fabrication methods such as hand lay-up process, spray lay-up process, vacuumed-bag, continuous pultrusion, and pulforming process, etc.; industries and home appliances such as automotive parts, building construction, sports kits, domestic goods, and electronic devices. The review lists various material combinations, fibre loading, fillers, and matrix that can aid in the improvement of material properties and the reduction of failures during mechanical testing of composites.

Characterization of prickly pear short fiber and red onion peel biocarbon nanosheets toughened epoxy composites

AbstractIn this research, the role of prickly pear short fiber and red onion peel wrinkled biocarbon nanosheets toughened epoxy resin composite was investigated. The main aim of this research was to find the effectiveness of adding biocarbon along with prickly pear fiber in the load‐bearing, thermal and electrical conductivity behavior of the epoxy resin composite. The biocarbon nanosheets were prepared for this present investigation from red onion peel waste using the pyrolysis process. The composites were characterized by American society of testing and materials (ASTM) standards and compared with previous results. The highest tensile strength and flexural strength were observed for 3 vol.% of biocarbon nanosheets up to 60% and 40% respectively than pure epoxy. Izod impact toughness and hardness values also increased with the inclusion of reinforcements by 5 vol.% around 93% and 90% correspondingly. Similarly, relative permittivity and dielectric loss enhanced about to 6.4 and 0.74 for 5 vol.% of biocarbon nanosheets. The thermal conductivity also improved with the addition of biocarbon nanosheets and maximum values up to 0.42 W/mK. This enhanced dielectric, mechanical, and thermally active composites might be employed as a microwave shielding material in electronic devices, automotive, and industrial applications for communications equipment that require shielding material with good mechanical properties.

Potentiometry for Cyanide Detection Applied to Fisheries Regulation

Illegal cyanide fishing is practiced by some fishers to capture agile and otherwise inaccessible reef fishes easily. Economic incentives had prevented discontinuation of the practice despite regulations present. Aside from the well-known toxicity of cyanide, it is a concern whether the fish is for ornamental purposes or human consumption that cyanide is being used because of the environmental damage it can cause by killing off non-target species. Currently, the cyanide content of fish is determined using an ion-selective electrode (ISE), with distillation as the mode of extraction of cyanide from tissues. This paper reports a modification of ASTM Method 500-CN-E, a method originally used to test for cyanide content in the wastewater. This paper outlines the process of determining the applicability of the method modification for analysis of fish tissue samples, in which no standard method was designed specifically for the matrix mentioned above. Although percent recoveries for cyanide at 0.05-10 mg/L range in spiked distilled water matrices are in line with the American Society of Testing and Materials (ASTM) results (90-105%), cyanide recoveries in spiked fish tissue matrices at the same concentration range are appreciably lower (~60-80%). For regulatory purposes, it serves as a temporarily acceptable method to detect cyanide-laden fish until a suitable method can be validated on international standards. However, to be accepted as a standard method, additional modifications may be needed or proven in inter-laboratory tests that the recovery of cyanide in fish is consistently low.

Corrosion Behavior of ASME SA-192 Steel Finned Tube by Wire Arc Spray in Temperature Control and High-Salt Environment

This paper proposes the corrosion behavior of ASME SA-192 steel finned tubes which were spray-coated with TH450 Chrome Nickel amorphous in a salt spray test chamber using 5% sodium chloride solution at a spraying speed of 12 mL/h according to The American Society of Testing and Materials (ASTM) B117 Standard. The salt spray test for 120 hours in the salt spray test in the chamber, the specimens that were exposed to moisture and salt fog in the surrounding air developed thin brown rust dots on the surface. The experimental results concluded that the specimens could withstand the corrosive environment for 5-15 years. The hardness test of coated specimens after the salt spray test for 480 hours showed that hardness and tensile strength of all specimens decreased due to surface damage from salt adsorption which resulted in blackish-brown rust and decreased tensile strength. Though, elongation of the coated specimens increased due to salt adsorption by the specimen surface, resulting in partial corrosion and rusting on the specimen surface. However, both parameters of the specimens exceed the ultimate tensile strength (UTS) standard test. Therefore, the spray coating with Chrome Nickel amorphous can increase the mechanical strength and corrosion resistance.

USE OF RESPONSE SURFACE METHODOLOGY (RSM) IN OPTIMISATION OF BIODIESEL PRODUCTION FROM COW TALLOW

In this study, beef tallow, waste from slaughterhouses was used as a feedstock for the production of biodiesel due to its high yield capacity, availability, and low cost. Sodium hydroxide and methanol were used as catalyst and solvent respectively. Characterization of oil and biodiesel samples were carried out using the Association of analytical chemist (AOAC) and American society of testing and materials (ASTM) respectively. Other characterization methods used are Fourier transform infrared spectroscopy (FTIR) and gas chromatographymass spectrophotometry (GC-MS) techniques. FTIR was carried out to characterize (identify the constituent elements) of both the feedstocks and their methyl esters. The fatty acid profile of the raw feedstocks and the produced methyl esters were obtained using the gas chromatograph to ascertain the % concentration of the different fatty acids. The physicochemical properties of the oils and biodiesel were also determined and compared with standards. Optimization of the processes was carried out using response surface methodology (RSM) under the platform of Design Expert 7.0.0 which uses statistical regression models. The optimized yield from transesterification of cow tallow using RSM was 83.82%, obtained with optimum operating parameters of Temperature (54.3oC), Time (51.65 mins), Catalyst concentration (1.82 wt%), Methanol/oil ratio (4.08 mol/mol) and stirring speed (302 rpm). This work thus not only confirms cow tallow as a viable feedstock for the production of biodiesel but also proves that a high enough yield of cow tallow biodiesel can be obtained at feasible reaction conditions. This study concluded that the use of response surface methodology proves to be a viable optimization technique albeit with its limitations in the transesterification process.

Production of Yellow Poplar Interior Plywood with Cottonseed-based Protein Adhesives

Defatted cottonseed (CS) and water-washed CS meals were prepared from glandless CS and were used in adhesive formulations to produce three-ply yellow poplar plywood panels. Adhesive resins were prepared from each protein meal with sodium bisulfite and one of two polyamido-amine-epichlorohydrin (PAE) wet strength agents, and the plywood panels were produced by hot pressing. Shear strength and water resistance were determined by American Society of Testing and Materials (ASTM) and American National Standards Institute for Hardwood and Decorative Plywood/Hardwood Plywood and Veneer Association (ANSI/HPVA) methods and were compared with the properties of plywood panels made with an adhesive formulated from a commercial soybean meal. Panels prepared from three protein meals had comparable shear strengths. The combinations of the two CS preparations and the two wet strength agents produced panels with acceptable wet resistant properties, whereas the soybean meal only produced acceptable panels with one of the wet strength agents. Because the panels prepared from the two CS meals had comparable properties, there appears to be no benefit to including a water-washing step to increase the meal’s protein level. In contrast with recent literature reports suggesting the addition of alkali to elevate the formulation pH was necessary with CS meal, suitable panels were prepared herein without the addition of the base. This difference may have been due to the slightly higher pressing temperature and longer press times used in this work compared with earlier results. The CS meals showed promise as formaldehyde-free hardwood-plywood wood-based adhesives for interior applications.

Dual-Frequency High-Electric-Field Generator for MRI Safety Testing of Passive Implantable Medical Devices

In this article, an electric (E) field generator is developed to generate uniform and high-strength E-fields at multiple frequencies. The system can be used to assess the radio frequency (RF) hazards of implantable medical devices (IMDs) in magnetic resonance imaging (MRI) environments. The novel system consists of three parts: 1) a signal generating and amplifying block; 2) a four-channel feeding network; and 3) a rectangular resonator box. Mixed modes are utilized to generate locally uniform E-fields inside the rectangular resonator at both 64 and 128 MHz. RF-induced heating for two passive IMD families are evaluated using both numerical and experimental methods inside the E-field generator. These results are compared with those obtained from standard American Society of Testing and Materials (ASTM) phantom testing. The results show that the novel E-field generator is capable of evaluating RF-induced heating for passive IMDs similar to that of the ASTM phantom. Furthermore, it integrates both 1.5- and 3-T RF-induced heating tests in a single system. It is much simpler compared to the ASTM test method which needs the RF coil as a source. Consequently, this small and efficient E-field generator can be used as an alternative system for RF-induced heating tests of passive IMDs in the MRI environment.

Measurement and Prediction of Thermal Conductivity of Volcanic Basalt Rocks from Warsak Area

Accurate values of thermal properties of rocks are needed for a number of engineering applications starting from heat losses in buildings to underground geothermal modeling. Igneous rocks are one of the major constituents of the Earth’s crust and are formed by the crystallization and solidification of molten magma. In this work, the thermal transport properties of porous igneous basalt rocks are measured using Transient Plane Source (TPS) technique under ambient conditions with air as saturant in pore spaces. Data are presented for fifteen samples of volcanic basalt rocks having different porosity values ranging from 0.267% to 9.432% by volume, taken from the place of Warsak near Peshawar city, located in the north of Pakistan. The porosity and density parameters are measured using the American Society of Testing and Materials (ASTM) standards. The mineral compositions of the samples are analyzed by X-ray fluorescence (XRF) technique. The specific gravity is predicted using the chemical composition of basalts and is compared with the experimental results. The thermal conductivity and thermal diffusivity values of the measured samples are also predicted using the mixing law and empirical models and results are compared with the measured data. Results show that the thermal conductivity of the studies of basalt samples decreases with the increase in porosity values, whereas no significant change has been observed in the thermal diffusivity data. Measured data are significant for geothermal modeling and in predicting heat losses in buildings wherever basalt rocks are used.

Analysis of the Crack Initiation and Growth in Crystalline Materials Using Discrete Dislocations and the Modified Kitagawa–Takahashi Diagram

Crack growth kinetics in crystalline materials is examined both from the point of continuum mechanics and discrete dislocation dynamics. Kinetics ranging from the Griffith crack to continuous elastic-plastic cracks are analyzed. Initiation and propagation of incipient cracks require very high stresses and appropriate stress gradients. These can be obtained either by pre-existing notches, as is done in a typical American Society of Testing and Materials (ASTM) fatigue and fracture tests, or by in situ generated stress concentrations via dislocation pile-ups. Crack growth kinetics are also examined using the modified Kitagawa–Takahashi diagram to show the role of internal stresses and their gradients needed to sustain continuous crack growth. Incipient crack initiation and growth are also examined using discrete dislocation modeling. The analysis is supported by the experimental data available in the literature.

Low-cost bending test laboratory kit

The big dimension and higher price of conventional bending test machine is making the school and start-up company hard to fulfilled. This study aims to demonstrate a new design of a low-cost and portable laboratory kit that is prospective for bending test. The kit is using hydraulic pressure tools with maximal capacity is about 6 tons. Economic analysis and smaller dimension of this kit (length x width x height of 700x100x750 mm) Showed that this kit is a low-cost and adaptable to classroom and easy to assemble for school. The different between another modification before bending test kit is on the pedestal and the suppressor of the kit is the which is allowing the machine to test materials with Thicker dimensions. The test result Obtained by calculating the maximum compressive force, moment of cross section innersia, flexural strength and elastic modulus of speciment. The result Also Compared with another test material from bending test machine with the American society of testing and materials (ASTM) standard and Showed that there is not much different in the test result for both. Further development of this kit is Potentially implemented an as an experimental tool for the student.

The Effect of Ambient Temperature and Implantation Time on the Material Properties of Two Viscosity-Differing Cements Using American Society of Testing and Materials Methodology.

Ambient temperature and time to implantation can affect the material properties of polymethylmethacrylate bone cement, and cement intrusion depth has been shown to affect implant fixation. The purpose of this study was to examine the effects of ambient temperature and time to implantation on depth of intrusion, and the effect of ambient temperature on setting time. Two types of cements were evaluated: cement A (Simplex P,medium Q7 viscosity) and cement B (Palacos R, high viscosity). Dough, working and setting times were determined, as well as intrusion depth, at different temperatures per American Society of Testing and Materials (ASTM) protocol F451. A vacuum mixer was used in a temperature- and humidity-controlled environment at 60, 65, and 70°F. At each temperature, the cement was placed into an intrusion mold at 0, 50, and 100% of working time. Increasing ambient temperature resulted in a significant decrease in dough and working and setting times for both cements (p = 0.038 - < 0.001). At each working time point and temperature, cement A showed significantly more intrusion than cement B (p = 0.044 - < 0.001). There was no effect of temperature on intrusion depth regardless of working time to implantation for either cement with the exception of cement B when comparing 60 versus 70°F at 0% working time (p = 0.004). Both cements showed a significant decrease in intrusion as time to implantation increased (p < 0.001). In conclusion, there are large inherent differences in properties of commercially available cements, and these properties are affected by such variables as time to implantation and ambient temperatures. An understanding of these properties may aid the surgeon in optimizing surgical outcomes.

Impact of using scatter-mimicking beams instead of standard beams to measure penetration when assessing the protective value of radiation-protective garments.

Use standardized methods to determine how assessment of protective value of radiation-protective garments changes under conditions employing standard beam qualities, scatter-mimicking primary beams, and a modified Hp (10) measurement. The shielding properties of radiation-protective garments depend on the spectrum of beam energies striking the garment and the attenuation properties of materials used to construct the garment, including x-ray fluorescence produced by these materials. In this study the primary beam spectra employed during clinical interventional radiology and cardiology procedures (clinical primary beams, CPB) were identified using radiation dose structured reports (RDSR) and fluoroscope log data. Monte Carlo simulation was used to determine the scattered radiation spectra produced by these CPB during typical clinical application. For these scattered spectra, scatter-mimicking primary beams (SMPB) were determined using numerical optimization-based spectral reconstruction that adjusted kV and filtration to produce the SMPB that optimally matched the scattered spectrum for each CPB. The penetration of a subset of SMPB through four radiation-protective garments of varying compositions and nominal thicknesses was measured using a geometry specified by the International Electrotechnical Commission (IEC). The diagnostic radiological index of protection (DRIP), which increases with increasing penetration through a garment, was calculated using these measurements. Penetration through the same garments was measured for standard beams specified by the American Society of Testing and Materials (ASTM). Finally, 10mm of PMMA was affixed to the inside of each garment and the DRIP remeasured in this configuration to simulate Hp (10). The SMPB based on actual CPB were in general characterized by lower kV (range 60-76) and higher half-value layer (HVL, range 3.44-4.89mm Al) than standard beam qualities specified by ASTM (kV range 70-85; HVL range 3.4-4.0mm Al). A lead garment of nominal thickness 0.5mm (D) had a DRIP of 0.8%, two lead-free garments of 0.5mm nominal thickness had DRIPs of 1.2% (A) and 2.2% (B), and a lead-free bilayer (C) had a DRIP of 1.4%. When standard beam qualities specified by the ASTM were used, the DRIP for D was 2.2%, 175% higher than the DRIP measured using SMPB, and for A, B, and C was 2.8%, 3.2%, and 2.9%, respectively. This was 133%, 45%, and 107% higher than the DRIP measured using SMPB. Differences between the DRIP of lead-alternative garments and the lead garment were reduced when measured with 10mm of PMMA. Using this method, the measured DRIPs were 2.2% (A), 3.1% (B), 2.5% (C), and 2.3% (D). Penetration of radiation through radiation-protective garments depended strongly on the methods and X-ray spectra used for evaluation. The DRIP was higher (i.e., protective value was lower) for lead-alternative garments than for lead garments in this evaluation. The DRIP was lower for all garments when SMPB based on actual clinical beam quality data were used to measure penetration compared to ASTM standard beams. Differences in penetration between lead-alternative and lead garments were less when the DRIP was measured with 10mm of PMMA between the garment and the chamber.