NCPTT is located on the campus of Northwestern State University of Louisiana. It’s offices and some laboratories are located in historic Lee H. Nelson Hall. Additional laboratories are located in Fournet Hall (NSU Science Building).
645 University Parkway
Natchitoches, LA 71457
NCPTT has six laboratories: three in Lee Nelson Hall and three hosted in Northwestern State University buildings. These laboratories house our scientific equipment and provide space for materials testing and analysis.
Surface Characterization and Measurement:
We have three 3D scanners that we use to document cultural heritage objects and create three dimensional renderings and videos. Outputs of these scans can include interactive PDFs where users can spin the image of an object and video walk-throughs of buildings. Each of the three scanners is used for a different size of object; the combined suite of scanners makes it possible for us to document objects that range from projectile points to buildings.
FARO Focus S
The FARO Focus S can scan in 360° and has an internal GPS to assist with the stitching of multiple scans. At each location, the instrument takes both laser scans and photographs, which can be combined for full color rendering using FARO’s SCENE software. We frequently use this scanner for documenting both the interiors and exteriors of historic buildings.
The data from the Faro Focus S can be used as a point cloud, photos, or with both combined. The rendered data can also be used for creating walk-throughs.
This scanner is being used for the Tenant Cabin Project. More information on the project can be found on our website, podcast, and blog.
Minolta Vivid 9i
The Minolta Vivid 9i scanner is used for mid-sized objects (basketry) to large objects (cars). Similar to the FARO Focus S, this scanner of highly portable and can collect both shape and color data. Depending on the size of the object being scanned, either the object is rotated to collect other views, or the scanner is moved around the object.
The data is handled with the Geomagic Studio software package, and can be exported into other formats.
This scanner has been used by Rayne Haskews to document local Creole art.
The NextEngine is a highly portable desktop 3D scanner and can be used to document small objects. It is paired with an object stage that allows the software to control the rotation of the object being scanned. The NextEngine captures both shape and image data; each object is usually scanned on three axes and the 360° scans of each axis are then stitched together to create whole objects.
Currently, we are scanning Poverty Point Objects (PPOs) and creating a digital type collection of the different shapes.
This instrument is used to objectively measure the color of a surface. This is a useful measurement in experiments examining surface appearance changes before and after treatments or weathering. We commonly use calculations from these data to determine the absolute change in a sample’s color across the duration of an experiment.
Konica Minolta Chromometer 400
This instrument can be used to take color measurements relative to a variety of color-spaces used for identification, including (but not limited to) L*a*b*, Munsell, Hunter Lab, and XYZ. We most commonly use the L*a*b* measurement parameters, which describes a surface’s color relative to the brightness-darkness axis (L*), the red-green color axis (a*) and the yellow-blue color axis (b*). This provides an objective measure of color in three values, which can locate the color in three-dimensional space. The L* values range from 100 (bright) to 0 (dark); the color axes have positive or negative numbers toward each of the color extremes, with 0 being neutral gray. When we take measurements at multiple points throughout an experiment, we can calculate the absolute change in color.
The Konica Miolta Chomometer is one of our most regularly used instruments and is currently being used in studies of crude oil removal from historic materials, herbicide effects on building materials, and aging of adhesives used in fossil conservation.
This instrument is used to measure the reflectivity or shininess of a surface. These data are useful in experiments examining surface appearance changes before and after treatments or weathering. In conservation, it is important to know whether surface coatings, cleaners or treatments will change the nature of the object’s appearance. We frequently use this instrument in conjunction with the colorimeter to characterize sample surfaces.
The instrument has three different angles of measurement, which make it possible to measure gloss of matte, semi-gloss, and high-gloss surfaces. The data are reported as gloss-units, and are measurements of the amount of light detected after it is bounced off the substrate’s surface. The instrument can take multiple measurements of a surface and report the average gloss and standard deviation.
Current projects using this instrument include crude oil removal from historic materials, herbicide effects on building materials, and aging of adhesives used in fossil conservation.
We have a suite of microscopes that allow us to examine samples under both transmitted and reflected light at high magnification. The microscopes vary in size from a stereo microscope to hand-held unit with USB connection.
This stereo microscope is frequently used to examine larger samples under incident light. The microscope is set up with an external set of ringlight and gooseneck lights that makes it possible for us to carefully control the illumination of the sample. The microscope also has a cable and camera that allows us to capture images using computer software.
This is a smaller stereo microscope that we also use to examine and photograph hand-samples. Similar to the MZ8, it is set up with incident lighting and camera.
This is our modular research microscope, which has the greatest amount of application flexibility. It has a series of light filters, including for certain UV wavelengths, and complete control of polarization.
NCPTT invested in a set of eleven Leica DM750P petrographic microscopes in order to teach a range of microscopy workshops including wood identification, ceramic petrography, and fiber identification. One of the microscopes has a camera accessory that makes it possible to show demonstrations on a large screen and capture images.
This is a small, handheld microscope that can be connected to a computer. The major advantage of this microscope is that it is highly portable and can be used on almost any surface.
We have two profilometers, which are tools used for mapping surface topography and texture. These data can be used to track how the surfaces of our samples change over the course of an experiment. Does treatment or weathering cause the surface to become, more rough? pitted? cracked? warped?
The Keyence is very user friendly profilometer that uses an optical light. The interface makes it possible to collect and analyze a range of data including optical images, height maps, 3D images, and roughness measurements of designated areas or lines. The data can be exported to excel for further handling. A sample that is two inches square takes less than three minutes to scan.
Solarius Solarscan System
The Solarius Solarscan System is the older of our two profilometers. This instrument uses a laser to collect surface profile data, and reports images and numerical values. The computer has been set up to allow remote access and driving. Scans can take four to eight hours.
These instruments are used for a range of chemical analyses including determining the chemical composition of materials, quantifying the presence (or absence) of contaminants, and studying how materials break down chemically.
We currently have two FTIR instruments, a ThermoFisher Nicolet iS50, and a PerkinElmer Spectrum 2. These instruments use IR radiation to excite movement of atomic bonds in the sample, and then measure which wavelengths of IR radiation are absorbed by the sample as a function of these movements. The wavelengths absorbed can indicate which functional groups are present, as well as any potential fingerprint for the sample. Fingerprints are a unique combination of peaks that are particularly useful when matching an unknown sample against a spectral library.
ThermoFisher Nicolet iS50
The ThermoFisher Nicolet iS50 is a benchtop model FTIR. That has several different accessories that allow for analyzing different types of samples. We currently have the ones listed below.
The Nicolet iS50 comes with a built-in diamond ATR accessory. ATR—or Attenuated Total Reflectance—is our most commonly used accessory. The sample is placed on top of the crystal—infrared wavelengths are bounced up into the sample, back down through the crystal, and measured by the detector. This technique works with samples in a variety of forms—liquids, gels, powders, solids—anything that can be pressed into complete and even contact with the crystal by the pressure foot without scratching the crystal. This accessory is being used extensively by Research Associate Abigail Poe in her work on herbicide effects on historic building materials.
iN5 FTIR microscope
The iN5 FTIR microscope allows us to focus the IR beam on very small or specific sections of a sample—either in reflectance mode where the light IR beam is bounced off of the surface of the sample or in transmission mode, where the beam is shone through a sample such as a transparent liquid or thin section and measured. The iN5 microscope requires the use of liquid nitrogen to cool the detector for reliable results. Dr. Cooper is currently using this accessory to examine how cyanoacrylate adhesives, when applied to fossils, degrade over time.
This accessory is the only one that does not use IR wavelengths, but rather a laser. The movements that absorb the IR energy and are measured by the FTIR are most commonly asymmetric. The Raman module works using same principles but uses a higher-energy laser and measures symmetric bond movements. The addition of the Raman Module to this suite creates a complementary data set, and expands the types of materials that we can examine.
Smart Diffuse Reflectance FT-IR Accessory
Diffuse Reflectance FTIR (or DRIFTS) analysis uses IR energy directed down into a powdered sample and measures the wavelengths that are scattered out of the sample as a result. For this technique all samples must be powdered, and individually mixed with potassium bromide (KBr) powder. This FTIR technique requires more sample preparation but works better for certain types of samples and projects. DRIFTS was used extensively in the study of anti-efflorescence coatings on masonry.
PerkinElmer Spectrum 2
This FTIR instrument can be used both as a benchtop unit in the lab, and packed up to take out into the field. It is currently set up with a diamond crystal ATR accessory and laptop for the greatest range of flexibility.
The PerkinElmer Spectrum 2 was used by Research Associate Elizabeth Salmon in testing the depth of penetration of oils and cleaners into her samples of historic building materials.
This instrument is used for determining the elemental composition of a material; it is non-destructive, non-invasive and portable.
Keymaster Tracer III-V and Bruker Trace Vi
We have two different models of pXRF: the Keymaster Tracer III-V and the newer Bruker Trace Vi. Both can be used to identify what elements are present in a sample through exciting the object with x-rays and reading the energy released as the atoms in the object relax. When atoms relax to a less energetic state, they release the energy as fluorescence characteristic to their particular element. The instrument measures the fluorescence at each wavelength, making it possible to identify which elements are present in the object and their relative proportions. The major differences between our two pXRF units are the instrument and software interfaces.
pXRF analysis is a very powerful tool in conservation because it is non-invasive and non-destructive—the instrument can be taken to the object, and it is not required that samples be taken. It can be used to quickly identify the presence/absence of heavy metal pesticides on objects in collections or do a more detailed elemental analysis of the elements present in a sample. There are also options for different calibration programs for the instrument, such as Precious Metals, or Ancient Coppers, which can be used to determine the composition some materials more specifically, such as the karats of gold in a piece of jewelry.
This instrument is can be used for determining the structure, crystallinity, or phase composition of a powdered sample. We use this for characterization of materials such as stone, mortar, and brick.
Bruker D2 Phaser XRD
The Bruker D2 Phaser is a benchtop XRD unit. It uses x-rays to examine short- and long-range molecular structure of a sample. The instrument bombards the powdered sample with a highly focused stream of x-rays, which interact with the material and bounce off of the atoms at angles characteristic of the sample’s molecular geometry, these bounced x-rays are then measured by the detector. The instrument will continue this bombardment while scanning through a range of angles to gather more complete structural data. The data is presented as a graph of the number of x-ray counts by angle of reflection. The main drawback to this technique is that it is moderately destructive: it requires a powdered or pressed-pellet sample for analysis.
These data are complementary to element composition data, such as that collected by x-ray fluorescence or mass spectrometry. For example, when examining glass and quartz, both have the elemental composition of SiO2 but very different long-range molecular structures. Glass has a random arrangement of SiO2 molecules with no long-range order; the XRD pattern for glass is characterized by very broad peak features. Quartz, on the other hand is a crystal and has a highly ordered structure of SiO2 that repeats; the XRD pattern is characterized by specifically spaced, sharp peaks characteristic of the long-range order of the SiO2 molecules.
Researchers at NCPTT have used XRD to examine the effects of herbicides on the built environment, and to examine corrosion on metals.
Weathering Simulation Instruments:
North-western Louisiana experiences some of the strongest UV radiation in the United States. We have mounted sample racks to the roof of our building so that we can conduct outdoor sample weathering experiments. The sample racks are angled to maximize UV exposure to the samples.
We have two weatherometer instruments that are used for accelerated weathering experiments. These instruments allow us to expose samples to intense UV light, heat and moisture and simulate worst-case-scenarios.
These are two of our most-used instruments. Many of our experiments are comparative studies of materials, treatments, or coatings, and one way that we gauge their performance is by comparing how well or badly they age over time when exposed to UV radiation, moisture and heat in the weatherometers.
There are a variety of ASTM standards available for accelerated weathering testing using the weatherometers that permit a range of different exposure conditions. Some of the ASTM standards are determined by material type being tested, for example non-metallic samples or adhesive joints. Exposure variables that can be controlled for these tests are UV-A or UV-B exposure, the length of time the UV lights are on, whether there is a moisture cycle, whether the moisture is introduced to the samples by direct spray or condensation, and the temperature under which the samples are exposed to these conditions.
Currently, these instruments are being used in studies examining the removal of crude oil from historic building materials, effects of herbicides on historic building materials, and the stability of adhesives used to consolidate paper shale fossils.
Materials Characteristics Tests:
This technique is used to take core samples for testing the concentrations of salt in a structure. It was adapted from the method and toolkit developed by Mesilla Valley Preservation, Inc. The major difference is the use of a hammer drill to help with taking a core sample from a harder material.
The hammer drill coring technique was used to collect samples from test walls treated with different anti-efflorescence coatings. The salinity data collected from the samples was used to determine the effectiveness of different anti-efflorescence coating products.
The salinity data are reported in grams of salt per gram of brick. Depending on how many samples are analyzed, it is possible to graph the data to show variability of salt content throughout a wall or structure.
This test is used to determine the adhesion-strength of coatings on a surface, such as paint or primer on wood.
DeFelsko PosiTest AT-A
This instrument is an automatic pull-test system that uses an actuator to exert pressure on the sample while pulling the applied dolly off. The dolly is applied to the surface coating being tested in advance using at two-part epoxy. Once the epoxy has set, the test can be conducted. The instrument measures the amount of pressure applied in psi and shows a curve of psi applied over seconds elapsed until the dolly and coating separate from the substrate; if the instrument is connected to a computer, it can log the data using PosiSoft software.
This instrument has been used in the study of paint and primer systems on weathered historic wood samples.
This test is used to determine the absorptivity of materials by measuring the length of time it takes a material to soak up 1 mL of water. We frequently use the Rilem test to examine how quickly building materials will absorb water/moisture. Running the test requires a specifically designed graduated tube temporarily sealed to the surface of the material with a putty, as well as water and a timer. The resulting data are reported as mL water absorbed by unit of time (either minute or second).
This test has been used in the anti-salt efflorescence coating study and during the examination of the effects of alternative herbicides on building materials.
Our 3D printer is used to create replica or scaled objects in plastic; these objects can be weighted or painted to more closely resemble the original object scanned.
This instrument is used to examine and map variations in density of structures/features in the ground.
This instrument is used to clean artifacts and objects. It requires that the base material and the material being removed (e.g. rust, coatings) have different compositions.
We have a suite of power and hand tools for cutting, grinding, polishing, coring and mounting samples for analysis.
We have a variety of saws ranging in size from handheld to bench-top to stand alone units. Depending on the material, some of the saws can be run dry or wet.
Saw models and types include: MK 880 brick saw, Buhler Isomet trim saw, Hillquist 1005 sectioning saw, a powered handsaw, and a band saw.
We have three different grinders, each of which can be fitted with a range of grits. The models include: the Buehler Ecomet 3 variable speed grinder, the Buehler Ecomet 4 variable speed grinder, and the
Buehler Handimet 2 roll grinder
Coring and Drilling
We have a variety of equipment used for coring and drilling depending on the type of sample we need, be it a solid core, or a powdered sample for analysis. Tools include the Delta drill press, a hammer drill, and a set of Dremel tools.
These instruments are used to measure and record relative humidity and temperature over extended periods of time. We have a couple different versions of the HOBO data loggers manufactured by Onset that can be used to measure internal or external conditions. These loggers can be programmed to record environmental data at various intervals ranging from seconds to hours. Certain HOBO models are equipped with Bluetooth capabilities, which allows for the data to be read and recorded remotely on a cell phone.
Currently, we are using these devices to monitor our own building and work conditions, as well as in experiments. One suite of HOBOs is being used to monitor the environmental conditions in model scale houses constructed to test the properties of different types of insulation.
Last updated: October 14, 2021