Abstract: A probe for penetrating and measuring electrical properties of a soil comprises a probe tip connected, via a coaxial cable, to electrical circuitry. The probe tip is convex and includes first and second electrodes with an electrode insulator therebetween. The first electrode is tubular and includes an interior surface defining a central opening extending through the first electrode. The second electrode includes a convex section extending away from the first electrode, and the convex section is configured for insertion into soil. The one end of the coaxial cable is disposed within the central opening of the first electrode, and the inner conductive core of one end of the coaxial cable connected to the second electrode, and the conductive shield of the one end of the coaxial cable connected to the first electrode.

Abstract: An in situ near infrared sensing unit includes a housing allowing the sensing unit to be inserted in a variety of media. A transparent window is formed in the sidewall of the housing. A sensing element is mounted inside the housing. The sensing element is configured to emit near infrared light provided from a light source external to the housing, and the sensing element is configured to collect near infrared light transmitted through the transparent window. A mirror is mounted in the housing at an angle with respect to the transparent window and opposite the sensing element. The angle allows the mirror to reflect the near infrared light, emitted by the sensing element, through the transparent window.