Thin Blade Research Articles

Mini-interfacial fracture toughness as a new validated enamel-bonding effectiveness test

Today׳s most commonly applied bonding effectiveness tests are criticized for their high variability and low reliability, the latter in particular with regard to measuring the actual strength of the adhesive interface. Objectives: in continuation of previous research conducted at dentin, we hereby aimed to validate the novel mini-interfacial fracture toughness (mini-iFT) test on its applicability to assess bonding effectiveness of contemporary adhesives when bonded to enamel. Methods: The 3-step etch&rinse (E&R) adhesive OptiBond FL (Kerr), the 2-step self-etch (SE) adhesive Clearfil SE Bond (Kuraray Noritake) and the two multi-mode adhesives Clearfil S3 Bond Plus (Kuraray Noritake) and Scotchbond Universal (3M ESPE), both used following a 2-step E&R and 1-step SE mode, were applied to clinically relevant, flattened enamel surfaces. A composite (Filtek Z100; 3M ESPE) build-up was made in layers. After 1-week water storage at 37°C, all specimens were sectioned perpendicular to the interface to obtain rectangular sticks. A mini-iFT notch was prepared at the adhesive-enamel interface using a thin diamond blade under water cooling. Finally, the specimens were loaded in a 4-point bending test until failure. Results: the mini-iFT onto human enamel was significantly higher for the adhesives applied in E&R mode versus those applied in SE mode. The lowest mini-iFT was found for the adhesives applied following a 1-step SE approach. SEM fracture analysis revealed that all fractures originated at the adhesive-enamel interface and that the induced crack propagated preferentially along this interface. Conclusion: mini-iFT appeared a valid alternative method to assess the mechanical properties of adhesive-enamel interfaces.

Analysis of the sharpness of blades for food cutting

Although the sharpness of a blade is responsible for cutting performance, there is no single and unambiguous literature definition of sharpness. The blade sharpness index (BSI) proposed by McCarthy et al. (Engineering Fracture Mechanics 74, 2205–2224, 2007) is a dimensionless number, derived from different cutting properties, to classify the sharpness of thin blades such as scalpels. In this study we transfer the BSI concept to blades with geometries typical in food cutting applications. After a series of cutting experiments at two velocities with blades that differed in wedge angle and abrasion state and by using three elastomers as substrate, we identified that the BSI can be regarded as a linear function of blade tip radius and force at cut initiation. The BSI was independent of cutting velocity, cutting substrate and wedge angle. Subsequently, cutting of foods with differently blunted blades revealed a specific impact on cutting performance, which depended on the food properties. Thus the BSI concept itself is helpful to classify the blade state, but it is less sufficient to evaluate the suitability of a knife with respect to a particular cutting application.

Uncracked joints in plain concrete pavements: causes, effects and possibilities of improvements

During the construction of Jointed Plain Concrete Pavements (JPCPs) in Chile, it was observed that joints remained uncracked. The objectives of this paper are to evaluate the effects of uncracked joints (UnCrJ) in JPCPs and to propose possible solutions or improvements to avoid or minimize this phenomenon. Considering low thermal amplitude as cause of UnCrJ, a rational-based, detailed and empirically validated model is used to predict UnCrJ and crack width. The modelled results are not only due to material changes but also to the location of the series of cracks in time in the JPCP system. The paper contributes with this rational approach, instead of an empirical-simplified one, to achieve the objectives. For the modelled conditions, the “as-built” slab length range is 8 m to 56 m instead of the 4 m designed one. Then, more curling, joint faulting, water infiltration in sealed joints and load transfer efficiency ≤ 70% are expected. The alternative solutions proposed are associated to innovations as short joints spacing, unsealed joints and saw-cuts up to 50% thickness made with thin blade (≤ 3mm), which was verified with new field evidence provided in the article.

Isolation and characterization of an improved strain of Porphyra chauhanii (Bangiales, Rhodophyta) with high-temperature resistance

The blades of the wild-type strain of Porphyra chauhanii (PC-WT) were irradiated with 60Co-γ rays and cultured at high temperature (30 °C) for 25 days. The surviving somatic cells of the irradiated blades were isolated enzymatically and were regenerated into whole blades and screened at high temperature. Vigorously growing blades at high temperature were selected and individually proliferated. A genetically homozygous and free-living conchocelis strain of TR-5 was obtained through parthenogenesis. Subsequently, TR-5 was compared with PC-WT for high-temperature resistance, growth, contents of major photosynthetic pigments, and the releasing ability of monospores and conchospores. The results showed that the survival percentage, division, and rhizoid germination of conchospores were not significantly different between TR-5 and PC-WT at 18 and 23 °C; but the survival percentages were 261.2 and 329.3 % higher, the division percentages were 42.8 and 72.6 % higher, and the rhizoid germination percentages were 94.3 and 199.5 % higher in the former than in the latter at 27 and 29 °C, respectively. When F1 gametophytic blades of TR-5 and PC-WT were firstly cultured at 23 °C for 30 days, and then cultured at 18, 23, and 27 °C for another 10 days, the absolute growth rates of TR-5 blades were 4.4, 4.3, and 10.4 times those of PC-WT and the relative growth rates were 1.1, 1.1, and 2.0 times those of PC-WT, respectively. The apical and middle parts of PC-WT blades were disintegrated due to the release of a large number of monospores after culturing for 15 days at 27 °C or 10 days at 29 °C, and only the basal parts of the blades remained intact. On the other hand, TR-5 blades grew rapidly with normal color and shape without releasing monospores and were slightly curled, even after being cultured for an additional 30 days. In addition, the contents of three major photosynthetic pigments (chlorophyll a (Chl. a), phycoerythrin (PE), and phycocyanin (PC)) and the conchospore numbers in TR-5 at a suitable temperature (23 °C) were 66.7, 244.2, 115.7, and 92.0 % higher than those of PC-WT, respectively. Meanwhile, the blades of TR-5 were 23.2 % thinner than those of PC-WT. The results indicated that TR-5 has thinner blade, higher contents of the major photosynthetic pigments, faster growth speed, higher temperature resistance, has larger number of conchospores released, and no monospore release as compared with PC-WT. It therefore has potential to be developed into a new variety suitable for cultivation in the aquaculture areas with high temperature in the coast of South China.

Long thin blade production and Late Gravettian hunter-gatherer mobility in Eastern Central Europe

The regular and systematic production of long blades (>120 mm) that maintain a thickness (<10 mm) of regular blades (<120 mm) is a particular phenomenon of the Upper Palaeolithic (40–10 ka BP) archaeological record of Eastern Central Europe. However, the mechanical underpinnings of manufacturing these long blades are still not fully understood. This paper presents experimental research that used heavy (∼800 g) and light (∼570 g) antler percussors to test the effect of percussor weight on the manufacture of Upper Palaeolithic type blades. Statistical analyses showed that a heavier percussor effectively increased the ability to achieve a fine thickness for long blades. The results are then compared to other experimental and archaeological assemblages to suggest that the use of heavy percussors may have played a role in lithic economy of Upper Palaeolithic mobile hunter-gatherers.

Energy-Based Ligation of Pulmonary Vessels: A Six-Year Experience With Ultrasonic Shears in Video-Assisted Thoracoscopic Lobectomy and Segmentectomy

Mechanical staplers are widely employed in minimally invasive anatomic lung resections, but have limitations when managing smaller pulmonary arterial and venous branches. Published data is lacking regarding the safety and efficacy of pulmonary vessel ligation using ultrasonic shears. We describe a single-surgeon experience employing ultrasonic shears for the ligation of pulmonary vasculature during lobectomy and segmentectomy, primarily in the setting of video-assisted thoracic surgery (VATS) resection. A retrospective chart review was conducted for all patients, who underwent anatomic resection, between 2008 and 2014. Charts were divided into 2 groups based on method of ligation (energy based or conventional). Dictated operative reports were reviewed and patient demographics, tumor characteristics, and complications were recorded. Ultrasonic shears were used for pulmonary vessel ligation (5 to 6 mm) in 82 of 283 anatomic resections. A total of 118 vessels were ligated with ultrasonic shears. The majority of patients (83%) in the energy-based ligation group underwent VATS resection. There were fewer complications in the energy-based ligation group (26% vs 38%; p = 0.05); however, rates of intraoperative transfusion, prolonged air leak, empyema, and return to the operating room were similar across the 2 groups, and no statistically significant difference was found. There were no postoperative complications directly attributable to ultrasonic vessel ligation. Energy-based ligation of small-diameter pulmonary vessels is a safe and useful adjunct in anatomic VATS resection and a viable alternative to mechanical stapling. Its narrow profile and thin blades make it ideal for ligation of pulmonary vasculature, particularly where the size and necessary clearance of mechanical staplers prohibit safe dissection.

Study on the Specific Energy Characteristics of the Ultrasonic Vibration Assisted Sawing Ceramic

Ultrasonic vibration improved the machining performance of a variety of brittle materials, and achieved good results in brittle materials machining applications. In this paper, the experiment about precision sawing engineering ceramic by using a thin diamond blade with and without ultrasonic vibration conditions was investigated. It is aimed to explore the effect of ultrasonic vibration on specific energy. The results show that ultrasonic vibration makes specific sawing energy having a significant reduction during material removal process. Under the ultrasonic vibration condition, the engineering ceramic’s materials removal way is changed. It changed from plastic removal to the removal of brittle fracture, which reduced the energy consumption of material removal.

Study on the Influence of Ultrasonic Vibration on the Specific Energy of Sawing Ceramic

The hard as well as brittle constituents are typically difficult-to-machined materials, and this character upsurges the machining cost. Many non-traditional machining methods were developed to improve its cost-effectiveness. Ultrasonic vibration assisted grinding has been improved the processing performance of a variety of brittle materials, and achieved good results in processing application. In this study, engineering ceramic was precisely sawn using a thin diamond blade with or without ultrasonic vibration conditions. During the sawing process, the specific sawing energy was investigated with the measurement of sawing forces to explore the influence of ultrasonic vibration. The results showed that the ultrasonic vibration made a significant reduction in specific sawing energy. The specific sawing energy decreased with the increase of the maximum undeformed chip thickness in both the sawing conditions; however ultrasonic vibration changed the trend of specific sawing energy in normal cutting mode from exponentially decreasing to a good linear decreasing. Under the ultrasonic vibration assisted sawing condition, the impact of the diamond grain on the engineering ceramic caused to much more material removal in brittle fracture mode. The reducing of the plastic transformation also reduced the energy consumption during the engineering ceramic sawing process.

Distal lower extremity coverage by distally based sural flaps: Methods to increase their vascular reliability

Although using distally based sural flaps is old and common, the described harvesting methods vary and often depend on unclear vascular anatomical data. We wanted, through a review of the existing harvesting techniques and our clinical experience, to synthesize these aspects in order to provide an optimal, safe and customized use of distally based sural flaps. Fifty-eight sural flaps were performed in 53.4-year-old patients in average, presenting in 81% of the cases one or more vascular comorbidities. The mean cover surface was of 30cm2. The flaps were mainly fasciocutaneous. The tunneling of the pedicle was performed in 34.5% of the cases. A skin blade was preserved above the pedicle in 37.9% of flaps. The short saphenous vein was anastomosed in 27.6% of the cases at the recipient site and ligatured distally in 19% of the cases. The mean follow-up was 18.9months. In 31% of cases, the skin paddle presented an obvious venous congestion during flap inset successfully treated with an anastomosis or a distal ligature of the short saphenous vein. We noticed in six other flaps (10.3%) a postoperative venous congestion having led to a skin paddle partial necrosis, of which five (8.6%) were treated without compromising the quality of the reconstruction. One patient required a coverage using another flap. When the microsurgery is not required or possible, the distally based sural flaps represent a safe level of the reconstructive armamentarium. Managing the pedicle's dissection and the venous drainage needs to be discussed case-by-case and adapted to peroperatory observations. The anastomosis or ligation of the small saphenous vein, as the existence of a thin skin blade under the skin paddle appear to increase vascular reliability of these flaps.

Piezoelectric shunt damping of a circular saw blade with autonomous power supply for noise and vibration reduction

Circular saws are widespread tools for machining metal, wood or even ceramics. Due to the thin blade and excitation by the workpiece contact of the cutting edges, circular saws are prone to vibration and intense noise emission. Damping the blade will lower the hearing protection requirements of the users and possibly increase precision. Therefore a new damping concept for circular saw blades is presented in this paper. It is based on negative capacitance shunted piezoelectric transducers which are applied to the saw blade core. The required energy for the electronics is harvested from the rotation by a generator, so that no change of the machine tool is required. All components are integrated into an autonomous saw tool. Finally, the system is experimentally investigated without rotation, in idling and in cutting condition in a circular saw test stand in the Institute for Machine Tools and Production Engineering (IWF) at TU Braunschweig. The experimental investigation shows a good reduction of the vibration amplitude over a wide frequency range in the non-rotating condition. When rotating, the damping effect is lower and limited to some narrow frequency bands. The proposed reason for the reduced damping effect in rotating condition consists in the saturation of the electronic circuits due to the limited supply voltage capabilities.

Out-of-plane neural microelectrode arrays fabrication using conventional blade dicing

This paper describes an optimized out-of-plane fabrication method for neural 3D high-aspect-ratio microelectrode array (MEA) based on a dicing technology platform (a standard procedure in semiconductor industry). The proposed MEA fabrication required important modifications in the dicing process. Since electrodes length reaches up to 4 mm, the main hindrance was the 2 mm cutting depth limit allowed for dicing machines with regular blades. This new procedure consisted on modifying Z-axis calibration, so cuts as deep as the exposure of blades were possible. The employment of proper blades for each fabrication step was also mandatory. Thin and high-exposure blades were used for deep cuts in silicon wafers, and V-shaped blades were employed to produce sharpened tips on the electrodes. Moreover, parameters as very low-cut speeds were essential to avoid wafer chipping and microcracks. Results showed high-precision and high-quality cuts in all steps of the 3D MEA fabrication, without unnecessary additional steps of etching post-processing. The optimized fabrication process was successfully demonstrated with a 3D neural probe array comprising 36 individually addressable electrodes.

Why is ice slippery?

Amit talks about the reason why ice is slippery. Ice is remarkably hard to get a grip on. The overwhelming consensus is that ice has low friction because of a thin film of liquid water coating its surface. Hence skaters balanced on thin metal blades can glide smoothly across the ice rink, but grind to a halt on the wooden floor beyond. The tricky part is how this liquid layer forms

Effect of Stator Shape on the Performance of Torque Converter

Torque converter is an enclosed hydrodynamic turbomachine, used in vehicles for smooth transmission of power and speed change from the engine to the transmission and torque multiplication. Torque converter consists of three major components: a pump that is connected to the engine shaft, a turbine connected to the transmission shaft, and a stator connected to transmission housing through a one-way clutch. Stator blades provide a guiding for the fluid flow. Stator is a main factor in controlling the torque ratio, pressure distribution and coupling point speed ratio. In this paper, the effects of the stator blade shape on overall performance have been investigated numerically at different speed ratios, using commercial software, ANSYS-CFX. Two torque converters with two different stator blade shapes are used for this study. The first stator has a large round nose, while the second stator is a thinner blade stator. At high speed ratio there is more blockage to flow of large inlet radius stator. Results showed that torque converter with thin blade resulted in an increase of torque ratio at fixed turbine and maximum efficiency. The bending of the thin blade caused a blockage to fluid flow.

Cost-effective joints configurations of concrete pavements for a sustainable infrastructure

Keywords: pavements concrete joints sustainable infrastructure Nowadays, there are Concrete Pavements (CPs) with Joints Configurations (JCs) that reduce initial costs about 20%. But are these JCs produced by Early-Entry Saw-Cutting (EESC), Unsealed Joints (UJs) and Shorter Joint Spacing (ShJS) able to maintain the traditional performance of CPs? The aim of this paper is to analyze the effects of the joints behaviour (JB) on the performance of CPs with these JCs. The JB is characterized by joints activation, opening, deterioration and Load Transfer Efficiency (LTE), not in an isolated but in a comprehensive way to determine not only the complete JB, but their effects on the CPs performance, so upon the users. The paper contributes not only with a comprehensive analysis of the innovative JCs, but also with new field experiences, that allow concluding the JCs can maintain or even improve the traditional performance of CPs if the saw-cutting depth ≥ 30% to assure 100% joints activation, joints opening ≤ 1.2 mm, so LTE ≥ 70%. UJs with thin blade (≤ 3 mm) and limited fines in the base can be used in CPs applications as streets, low volume roads, parking lots, bus corridors (moderate rainfall) and any CP where the seals do not work well.

Ježekite, Na8[(UO2)(CO3)3](SO4)2·3H2O, a new uranyl mineral from Jáchymov, Czech Republic

Jezekite (IMA2014-079), Na-8[(UO2)(CO3)(3)](SO4)(2)center dot 3H(2)O, is a new uranyl carbonate-sulfate mineral from Jachymov, Western Bohemia, Czech Republic. The new mineral was found on samples from the Geschieber vein in the Svornost mine. It occurs as a crystalline crust composed of thin, bladed prismatic crystals of yellow to sulfuric yellow color on a gangue along with andersonite, cejkaite, schrockingerite and ubiquitous gypsum. It is a supergene, low-temperature mineral formed by hydration-oxidation weathering of uraninite associated with post-mining processes. Jezekite is hexagonal, space group P-62m, with unit-cell parameters a = 9.0664(11), c = 6.9110(6)angstrom and V = 491.97(12)angstrom(3), Z = 1. Crystals are thin blades elongated along [001]. Crystals exhibit the forms {001}, {1-11}, {100} and {010}, commonly forming twins/intergrowths with a twin plane parallel to [001]. Jezekite is light yellow to sulfuric yellow and has a very pale yellow streak. It exhibits a bright greenish white fluorescence under both long-wave and short-wave UV. It is transparent with a vitreous to pearly luster. The mineral has a Mohs hardness similar to 2; it is brittle, with uneven fracture and a perfect cleavage on {001} and along [010]. The calculated density based on the empirical formula is 2.966 g/cm(3). The mineral is optically uniaxial (+), with omega = 1.484(2) and epsilon = 1.547(2) (589 nm). It is non-pleochroic. The chemical composition of jezekite (wt. %, electron-microprobe) is: Na2O 27.92, SO3 18.49, UO3 32.85, CO2 (calc.) 15.08, H2O (calc.) 6.17, total 100.51, which yields the empirical formula Na-7.88 (UO2)(CO3)(3)(S1.01O4)(2)center dot 3H(2)O (based on 22 O apfu). Prominent features in the Raman spectrum include the O-H stretching vibrations, symmetric stretching vibrations of (UO2)(2+) ions, and stretching and bending vibrations of symmetrically non-equivalent CO3 groups and highly disordered SO4 tetrahedra. The eight strongest powder X-ray diffraction lines for jezekite are [d(obs)angstrom(I-rel.) (hkl)]: 7.861(59)(100), 6.925(20)(001), 5.193(100)(101), 4.534(44)(110), 3.415(23)(201), 2.751(17)(112), 2.728(20)(211), 2.618(25)(300). The crystal structure of jezekite (R = 0.043 for 444 reflections with I-obs > 3 sigma[I]) contains finite uranyl tricarbonate clusters linked through the Na-O bonds to form sheets of the composition {Na-2[(UO2)(CO3)(3)]}(2-) parallel to (001). The adjacent sheets of polyhedra are also linked through Na-O bonds to the six Na2 atoms and highly disordered sheets of composition {[(SO4)(2)(H2O)(3)]}(4-) into a sandwich-like structure. The new mineral is named after Professor Bohuslav Jezek (1877-1950), a prominent Czech mineralogist and crystallographer

Porosity of Solid and Cored Turbine Blades of Aircraft Engines

Paper presents results of quantitative evaluation of porosity conducted on big, thin walled airfoil turbine blades made from Inconel 713C alloy. To decrease mass, blades are design and manufacture like thin walled cored castings. Manufacturing of big thin walled casting airfoil blades is extremely difficult. During exploitation casting work undergo cycle fatigue. In that cause casting should be free of casting defects, including porosity. Conducted research focused on Inconel 713C superalloy pouring temperature effect on porosity level of cored casted turbine blade. Results were compared to porosity of solid casted turbine blade. It was found that porosity of cored blades is lower than solid blade porosity. In cored blades higher porosity is located on airfoil convex side. Airfoil concave side has lower porosity.

The strengthening mechanism of laser shock processing and its application on the aero-engine components

Aiming at the application problems of laser shock processing on the aero-engine high temperature components, thin blade, blade- mortises/tenon teeth and other complex parts (regions), we carried out a systematical research on surface nanocrystallization induced by laser shock processing. This article summarized many studies about the characterization, theory and thermal stability of surface nanocrystallization of metal materials in various aero-engines. Moreover, we proposed a new strengthening mechanism of laser shock processing which was based on surface nanocrystallization and compressive residual stresses. Thereby, the application temperature of laser-peened high temperature components could be improved, and the engineering applications of laser shock processing on thin-wall construction, mortises/tenon teeth and other special parts (regions) were introduced. The research on laser-induced surface nanocrystallization and compound strengthening mechanism, which broadens the study area and application field of laser shock processing.

Patellaplasty, as an Alternative to Replacing Patella in Total Knee Arthroplasty

Aim: In tricompartmental osteoarthritis of the knee, the patellofemoral articulation is severely affected due to degenerative changes. Patellaplasty is done as a part of total knee arthroplasty in these cases to smoothen the articular surface of patella. However, an ideal technique with easy reproducibility has been scarcely reported for the same. Method: We describe a method of using electrocautery and power saw with thin blades for patellaplasty. Results: Using this technique, we have produced results, which are comparable with cases where patellar resurfacing has been done. Conclusion: This described method for patellaplasty is easy with good reproducibility.

The relationship between numbers of bacteria on surfaces and in deep tissues of mechanically tenderized beef

The objective of the study was to identify factors affecting the fractions of the bacteria naturally present on surfaces of beef cuts that are carried into deep tissues when the meat is mechanical tenderized by piercing with banks of thin blades. The surfaces and ten strips of meat from the deep tissues of beef primal cuts tenderized first and last on each of five days at a retail store meat fabrication facility were sampled for enumeration of total aerobic counts. Each strip was excised from the whole thickness of a cut after surfaces were sterilized. The mean log numbers of total aerobes recovered from the surfaces of cuts tenderized first or last each day were 2.18 and 1.57 log cfu cm−2, respectively. The mean log numbers recovered per strip from individual cuts tenderized first or last each day ranged from 0.30 to 1.45 and from 0.03 to 1.04 log cfu, respectively. These findings indicate that bacteria from the tenderizing equipment augmented the numbers of aerobes on the surfaces of cuts tenderized first each day, with some of the additional aerobes being carried into deep tissues. Subsequently, pieces of cuts stored in air at 2 °C were tenderized at a laboratory using commercial equipment. Each cut was divided into three pieces with one piece being not treated, one being sprayed with water and one being sprayed with 5% lactic acid. The mean log numbers of total aerobes recovered from the surfaces of not treated pieces of cut stored for 0, 2, 4, 6, 10 or 14 days were 0.6, 0.8, 2.6, 4.2, 8.5 and 8.9 log cfu cm−2, respectively. No aerobes were recovered from the deep tissues of any of the pieces of cuts tenderized on day 0. Mean log numbers recovered from the deep tissues of not treated tenderized pieces of cuts stored for 2, 4, 6, 10 or 14 days were 0.3, 0.3, 2.2, 7.8 and 8.1 log cfu per strip, respectively. Spraying with 5% lactic acid reduced the mean log numbers of aerobes on pieces of cuts stored for 2, 4, or 6 days by 1, 2 or 2 log units, respectively, but did not reduce the numbers on pieces of cuts stored for 10 or 14 days. Mean log numbers recovered from the deep tissues of tenderized pieces of cuts sprayed with 5% lactic acid were not significantly different (P > 0.05) from the mean log numbers recovered from the corresponding, tenderized not treated pieces of cuts. These findings showed that the fraction of the total aerobes on cut surfaces that are carried into deep tissues during mechanical tenderizing can vary with the stage of growth of the spoilage flora; and that reduction of numbers of aerobes on the surface by treatment with lactic acid before tenderizing does not necessarily reduce the numbers carried into deep tissues during tenderizing.

Estimating variation in surface emissivities of intertidal macroalgae using an infrared thermometer and the effects on temperature measurements.

Accurate measurements of surface temperatures with an infrared (IR) thermometer require input of the emissivities of the surfaces being measured; however, few determinations of the emissivities of intertidal organisms’ surfaces have been made. Emissivities of intertidal macroalgae were measured to determine whether algal species, measurement angle, hydration, and layering affected them. Emissivities were similar and averaged 0.94 among 11 of 13 species. The species with lower and more variable emissivities (Chondracanthus exasperatus and Desmarestia viridis) differed in morphology from the other species, which were relatively flat thin blades with little surface texture. Measurement angle caused emissivities to decrease significantly in Mazzaella splendens but not in three other species. Hydration and layering of Ulva lactuca also had no effect. At 22 °C, measured temperatures were within 1 °C of actual temperatures when thermometer emissivity settings ranged from 0.75 to 1.00. When emissivities were set lower than actual values, measured temperatures were lower than actual temperatures at 15 °C and higher than actual temperatures at 60 °C. When the IR thermometer was used to measure surface temperatures of nine species of intertidal algae immediately before they were inundated by the incoming tide, temperatures were higher in mid intertidal than low intertidal individuals and higher on a sunnier day than an overcast day. Temperatures of U. lactuca increased with increasing height on the shore, but temperatures of Ulvaria obscura did not. Temperatures were also higher in Fucus distichus blades than receptacles, and lower in U. lactuca and M. splendens occurring in the lower layers of stacks of algae.