Inexpensive Apparatus Research Articles

An Inexpensive Apparatus for Degreasing Skulls

An Inexpensive Apparatus for Degreasing Skulls

An intensity-stabilised He-Ne laser for measuring small magneto-optic Kerr rotations from thin ferromagnetic films

The change in intensity of light transmitted through an analysing polariser after reflection from a ferromagnetic surface can be related to the magneto-optic Kerr rotation. The construction of an inexpensive apparatus for measuring small rotations based on the use of an external intensity stabiliser for a laboratory He-Ne laser is discussed. The authors examine the limitations on the signal-to-noise ratio as consequence of the detector noise, shot noise and technical noise present in the system. An intensity stability of 0.05% has been achieved and has enabled them to obtain hysteresis loops from a 5 nm thick iron film with a signal to noise ratio of 40:1 for a data collection time of 100 s.

An undergraduate laboratory experiment for measuring the energy gap in semiconductors

A simple and inexpensive apparatus is described which allows fast and reliable measurements to be made of the temperature dependence of the electrical conductivity in a semiconductor sample. The energy gap can be calculated from the data taken in the intrinsic region, and the temperature dependence of the majority carrier mobility can be deduced from measurements taken in the extrinsic region.

Mobile, High-Wind, Balloon-Launching Apparatus

In order to place instruments for measuring meteorological and electrical parameters into thunderstorms, an inexpensive apparatus has been developed which makes it possible to inflate, transport, and launch balloons in high winds. The launching apparatus is a cylinder of bubble plastic that is made by joining the sides of the cylinder together with a velcro rip strip. A balloon is launched by pulling the rip strip rapidly. This allows the balloon to pop upward into the ambient low-level wind and carry its instrumentation aloft. Different-sized launch tubes are constructed to accommodate particular sizes of balloons. Balloons have been launched in winds of about 20 m/s.

Synkinematic microscopy of transparent polycrystals

Deformation of weak, polycrystalline materials in thin section, on the stage of a petrographic microscope, offers insight into the origin of optical microstructures similar to microstructures in naturally deformed rocks. Sample materials used to date include several soft minerals (ice, carnallite, bischofite, nitratite) and various organic plastic materials. They can be simple-sheared or pure-sheared at temperatures to 300°C, at a variety of strain rates, using relatively simple and inexpensive apparatus. The complete microstructural evolution can be recorded photographically, along with the complete kinematic history. Research applications have focussed on dynamic recrystallization, and progress has been made towards understanding how the average grain size is maintained constant in steady-state recrystallization flow. Records have been obtained of the development of various crystal-plastic microstructures and of lattice reorientation trajectories during flow. Teaching applications have begun to be developed, and several videotapes are available. Future technical developments are expected to permit stress measurement or control during experiments, and synkinematic recording of lattice reorientation. Numerous research areas invite attention. These include investigation of the microstructural developments that precede faulting, the behaviour of deforming crystal-melt systems, and the behaviour of dynamically reactive, multi-phase systems.

Whole-body fluorography using black light fluorescent tubes.

A simple and inexpensive apparatus and techniques are described for recording fluorographs of whole-body cryosections of mice injected with a fluorescent compound. The apparatus was constructed with commercial fluorescent tubes which emit UV light of 300-400nm and a single-lens reflex camera equipped with UV cut and Kodak Wratten filters.Autofluorescence of the whole-body section observed by using this technique was discussed and the effects of lapse of time after cryosectioning, fixation, and pH on the autofluorescence were also investigated. Autofluorescence of the skeletal muscle, myocardium, smooth muscle, brain, kidney cortex and pancreas was intensified with time after cryosectioning, but that of the Harderian gland was gradually faded. In other tissues, autofluorescence remained unchanged up to 2 weeks after cryosectioning. All fixatives used in this experiment reduced the autofluorescence of tissues and organs. Among the fixatives, 100% acetone had the least effect on autofluorescence. At pH4, autofluorescence of all tissues was considerably increased in comparison with pH7. With increasing pH, autofluorescence of most tissues was gradually reduced except for the bones and the Harderian gland.

Echography: a practical for undergraduate medical students

A simple, inexpensive echography apparatus for educational purposes is presented. It can be used to make undergraduate medical students familiar with the principles and limitations of echographic techniques in the usual A and B modes. The object of the A-mode experiments is to illustrate the fundamental importance of the measuring distance in echography. The role of the acoustic impedance is also discussed, and the indispensability of coupling gel is demonstrated theoretically and experimentally. The B-mode experiment yields an echographic image of an object. It is shown that the axial resolution depends on the duration of the ultrasound pulse, and the lateral resolution on beam geometry.

Quantitative assessment of the clinical electroretinogram

The clinical application of electroretinography has been limited until now by the lack of standardisation, especially of stimulus conditions. Normal values for the electroretinographic response parameters can only be used if patients are examined under the conditions which were given for the examination of healthy subjects. It is shown in this paper that the inexpensive apparatus designed by Kooijman and Damhof (1981) can be calibrated by any user simply and at justifiable expense. Normal values for the amplitudes and peak times for the a- and b-wave are presented. The normal range of the values has been defined with regard to the frequency distribution. According to the authors' results, methods of descriptive statistics in skewed distributions are mainly necessary at low stimulus intensities. The descriptive methods for normal distributions were regularly applied at higher stimulus intensities. In general, however, ERG parameters are normally distributed as shown by the distribution of the residuals between the linear regression of the parameter to the logarithm of the corneal illuminance and the measured values. The influence of age on the amplitude was calculated according to the results of Lehnert and Wünsche (1966) and the lower limits of the normal range are given for four age groups. The data presented here may be used as normal values provided that the simple calibration methods are applied. Thus electroretinography is no longer a method merely for the laboratory, but can be used in clinics and offices as well. However, a prerequisite is that the physician has sufficient experience in ophthalmological electrophysiology.

Simple computer controlled apparatus for in vitro mechanical testing of connective tissues

Connective tissues are viscoelastic and so a series of experiments, at carefully controlled loading rates, is required to determine their mechanical properties. This paper describes a simple, inexpensive apparatus for performing these experiments; it is based on a ball screw driven by a microcomputer controlled stepper motor.

Rapid and accurate electrical resistivity measurements of bulk metal and alloy samples

An inexpensive apparatus using the eddy current decay method for measuring the resistivity from bulk samples is described. In order to rapidly accumulate data on the variation of the eddy current, the analogue signal is digitised and stored in a specially developed fast transient device (FIFO). The digital data are then transferred to a microcomputer for further analysis. The resistivity of an Al-1.56 at.% Cu alloy has been measured using this apparatus in order to determine the solute concentration after different aging times at 210 degrees C.

Angular scanning stage for glancing-incidence surface EXAFS

In this paper a simple and inexpensive angular positioning apparatus is described which can be applied to measurements of x-ray reflectivity and extended x-ray absorption fine structure (EXAFS) at glancing angles of incidence. An efficient interactive alignment procedure is discussed and the performance of the device is given.

Apparatus for grinding otoliths of larval and juvenile fish for microstructure analysis

Apparatus for grinding otoliths of larval and juvenile fish for microstructure analysis

A simplification of the differential thermal analysis method to determine the latent heat of fusion of phase change materials

A simplified version of differential thermal analysis has been developed resulting in an inexpensive apparatus for determining the latent heat of fusion of phase change materials. The experimental results performed with three samples show that the present method yields results which agree within 5% with the measurements of sophisticated differential scanning calorimetry apparatus.

Dialysis: a simple method of separating labelled bacterial DNA and tritiated thymidine from aquatic sediments

Bacterial growth in aquatic sediments can be measured by the rate at which [ methyl- 3H]thymidine ias incorporated into bacterial DNA. Radioactively labelled macromolecules are separated from the unincorporated radioactive precursor by either filtration, precipitation or dialysis. The efficiency with which these methods separate labelled bacterial DNA, thymidine and other low-molecular weight compounds are compared. Dialysis proved to be the most effective with marine sediments comprising clay, siliceous sand or calcium carbonate. A simple, inexpensive dialysis apparatus capable of handling large numbers of samples is described.

Apparatus for combined electrochemical, optical and ESR studies on conducting polymers under controlled atmosphere

A simple, inexpensive and portable apparatus has been designed for combined optical and ESR studies on electrochemically prepared conducting polymer films. It permits electrochemical studies to be performed as well as transferring samples to other types of measuring devices under controlled atmosphere. The apparatus presented may easily be adapted to other applications.

Microwave measurements of a fluorescent lamp plasma

We describe an undergraduate plasma physics experiment using an easily constructed and inexpensive apparatus that nevertheless involves the more advanced physics of the interaction between plasma and electromagnetic radiation. The experiment is based on the readily available plasma of a fluorescent lamp. The lamp is placed inside a resonant cavity and the shifts in the frequencies of cavity resonances are used to determine the plasma density as a function of time. We describe a circuit that allows measurements to be made of the decay of the afterglow plasma, and show experimentally determined decay rates and densities that are consistent with the literature on fluorescent lamps and gas discharges.

An inexpensive dual-excitation apparatus for fluorescence microscopy.

Ion sensitive indicator molecules can be employed in conjunction with fluorescence microscopy in single cells to measure rapid changes in the intracellular concentration of several ionic species. A number of these probes (e.g. fura-2) require the capability of measuring emission intensity at two excitation wavelengths to quantitate properly intracellular ion concentration. We have developed a simple dual-excitation apparatus for use in such applications. The apparatus switches the excitation filter within 150 ms. This economical apparatus is well suited in situations where the ionic concentration of interest is changing relatively slowly. Moreover, by synchronizing the device's action with an external stimulus, rapid and reproducible ionic changes in excitable tissue also can be measured.

Xerographic time of flight experiment for the determination of drift mobility in high resistivity semiconductors

Drift mobility in high resistivity semiconductors can be determined from xerographic time of flight (XTOF) techniques whose principles are different from the well known Haynes-Shockley experiment. A practical and inexpensive XTOF apparatus which can be utilized in investigating high resistivity semiconductors is described in detail. Some examples of XTOF transient current waveforms in amorphous selenium-based photoreceptors and method of analysis are presented.

An inexpensive apparatus for producing graded spinal cord contusive injury in the rat

We recently described an experimental model of spinal cord contusive injury in the rat in which a modified weight-drop apparatus is used to generate reproducible mild, moderate, or severe final functional deficit. We now report several inexpensive alternatives for portions of the original apparatus which allow the production of contusive injuries without the necessity of an expensive commercial stereotaxic frame or custom-machined clamp holders.

A simple apparatus for sampling sea surface microlayers

A simple and inexpensive apparatus for sampling the upper 3 mm of sea surface microlayers is described. It is constructed from plexiglass and is quick in operation and suitable for studes of the microlayer ecosystem. In the vertical dimension, the term 'surface microlayer' of seawater refers to a depth scale ranging from < 1 mm to a few centimeters (Parker 1978, Hardy 1982). Surface microlayers of the marine environment tend to concentrate phytoplankton populations (phytoneuston) with abundance, pigment composition, photosynthetic activity, taxonomic diversity and dominance different to underlying communities (Harvey 1966, 1974, Roy et al. 1970, Marumo et al. 1971, Hardy 1973, 1982, Callagher 1975, Manzi et al. 1977, Wandschneider 1979, Hardy & Apts 1984). Assessing the overall behaviour of phytoplankton in surface microlayers requires the use of a collection device quick in operation and effective in providing sufficient water from a large enough surface area for a statistically reliable population sample (Wangersky 1976). The most commonly used samplers (Garrett 1965, Harvey 1966) do not fulfill these criteria because they either do not collect large enough samples or require a great deal of sampling time to do so (Wangersky 1976). This paper describes a simple device for continuous sampling of sea surface microlayers of 3 mm thickness. Sample thickness for this equipment is larger than for Garrett's (1965) screen collector (100 to 250 pm) but thinner than for the box collector (4 mm) designed by Hardy (1973). The sampler consists of 2 square plexiglass plates of 45 cm2 surface area and 4 cm thickness, cemented to make a box (water collector) with 3 mm inside height (Fig. 1). One side of the box is left open (inlet opening) to form a 'window' of 44 cm X 44 cm X 3 mm inside dimensions. The upper plate has a hole of 4.0 mm diameter (outlet opening) in the center, which is connected by a rubber tube (4 m long) to a 5 1 vacuum flask. The under-surface of the box is supported by Fig. 1. The sampler. A: hand pump; B: vacuum flask; C: water collector. Arrows indicate water movement via the water collector and rubber tubing to the vacuum flask O Inter-Research/Printed in F. R. Germany 208 Mar. Ecol. Prog. Ser. 39: 207-208, 1987 cork of 1 cm thickness to provide sufficient buoyancy so that the box floats with its inlet opening just covered by the upper 3 mm of water. The box can be lifted by wires attached to its 4 corners. When the sampler is allowed to float on the sea it is immediately filled with water from the upper 3 mm layer through its inlet opening. A hand pump empties the air from the vacuum flask and water from the sampler is sucked continuously via the outlet opening and the rubber tubing into the flask. Slow horizontal translocation of the device allows sampling from a large area. Advantages of the sampler are: (1) It is inexpensive, light in weight and simple in operation; (2) It is capable of continuous and relatively uniform sampling of sufficient water from a large surface area, and thus suitable for s tuhes of the microlayer ecosystem.