*Who May Submit Proposals: Proposals may only be submitted by the following: -Institutions of Higher Education (IHEs) - Two- and four-year IHEs (including community colleges) accredited in, and having a campus located in the US, acting on behalf of their faculty members.Special Instructions for International Branch Campuses of US IHEs: If the proposal includes funding to be provided to an international branch campus of a US institution of higher education (including through use of subawards and consultant arrangements), the proposer must explain the benefit(s) to the project of performance at the international branch campus, and justify why the project activities cannot be performed at the US campus. *Who May Serve as PI: Investigators must contact a RARE program director in CBET or CHEto confirm eligibility prior to submission, depending upon which division the PI will apply to. The investigator will receive an e-mail confirmation of eligibility, which must be uploaded as a Single Copy document with the proposal submission. The investigator must hold a PhD in engineering, chemistryor a closely related discipline, with prior research experiences in an area within the scope of the Division of Chemical, Bioengineering, Environmental, and Transport Systems or Division of Chemistry. Application to the RARE program is not limited by demographics. Tenured or tenure-track faculty may apply. Adjunct, affiliated, research, or teaching faculty may apply if they are employed either full or part-time by an institution of higher education (IHE), provided they have a plan to seek future employment on the tenure-track. Other qualified individuals who lackIHE affiliation may apply, provided they have identified a senior research mentor at an IHE; in this select case, the mentor may serve as PI(see Additional Eligibility information below). Investigators that have previously received a Track 1 RARE award are ineligible for a second award of either track. Investigators that have previously received a Track 2 award are ineligible for a second Track 2 award.Investigators that have previously received a Track 2 RARE award are eligible for a Track 1 award, if the Track 1 topic is related to the prior Track 2 award. PIs that are eligible for a CAREER submission are ineligible for a RARE submission. Proposals from investigatorswho have had no change in career status for an extended period of time are encouraged. The RARE investigator must demonstrate a substantial decrease in research metrics that result from the research hiatus to receive a confirmation of eligibility.The metrics must be communicated to a RARE program director to receive an e-mail confirmation of eligibility. Also, full documentation of these metrics should be included in a full curriculum vitae that is uploaded as a Single Copy document with the proposal. Applicable research metrics include: (1) research publication activity; (2) external research support as PI or co-PI, at a funding level that is consistent with a typical CBET or CHEindividual investigator award; (3) resources with which to collect preliminary data. A Track 1 investigator must demonstrate a decrease in one or more metrics. A Track 2 investigator must demonstrate a lack of activity in all three metrics in the new area of interest (publications and funding in other areas are allowed). Examples of acceptable documentation of these metrics include: a full curriculum vitae with all publications and funding activity, a budget balance sheet showing funds from current awards are fully committed, a lack of support for research staff, reviews from a proposal saying preliminary data is needed, declined seed grant proposal from home institution, a lack of access to a necessary collaborator. Other metrics and means for documentation of the metric may be considered, after consultation with a RARE program director. The curriculum vitae should be formatted such that a decline i