This is a big challenge because they are very small (order of micron in size) and are somewhere (we don't know where) on a HUGE collector — at least on the scale of the particle size — about a tenth of a square meter.
1	This	this	PRON	DT	Number=Sing|PronType=Dem	5	nsubj	5:nsubj	Discourse=evaluation-comment:61->57:2|Entity=(61-abstract-giv:act-cf2-1-coref)
2	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	5	cop	5:cop	_
3	a	a	DET	DT	Definite=Ind|PronType=Art	5	det	5:det	Entity=(61-abstract-giv:act-cf2-3-coref
4	big	big	ADJ	JJ	Degree=Pos	5	amod	5:amod	_
5	challenge	challenge	NOUN	NN	Number=Sing	0	root	0:root	Entity=61)
6	because	because	SCONJ	IN	_	10	mark	10:mark	Discourse=causal-cause:62->61:0
7	they	they	PRON	PRP	Case=Nom|Number=Plur|Person=3|PronType=Prs	10	nsubj	10:nsubj|20:nsubj	Entity=(11-object-giv:act-cf3-1-ana)
8	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	10	cop	10:cop	_
9	very	very	ADV	RB	_	10	advmod	10:advmod	_
10	small	small	ADJ	JJ	Degree=Pos	5	advcl	5:advcl:because	_
11	(	(	PUNCT	-LRB-	_	12	punct	12:punct	Discourse=elaboration-additional:63->62:0|SpaceAfter=No
12	order	order	NOUN	NN	Number=Sing|Typo=Yes	10	parataxis	10:parataxis	CorrectForm=on the order|Entity=(64-abstract-new-cf6-1-coref|XML=<sic ana:::"on the order"></sic>
13	of	of	ADP	IN	_	14	case	14:case	_
14	micron	micron	NOUN	NN	Number=Sing	12	nmod	12:nmod:of	Entity=(65-abstract-new-cf7-1-coref)
15	in	in	ADP	IN	_	16	case	16:case	_
16	size	size	NOUN	NN	Number=Sing	14	nmod	14:nmod:in	Entity=(66-abstract-new-cf8-1-coref)64)|SpaceAfter=No
17	)	)	PUNCT	-RRB-	_	12	punct	12:punct	_
18	and	and	CCONJ	CC	_	20	cc	20:cc	Discourse=joint-list_m:64->62:1
19	are	be	AUX	VBP	Mood=Ind|Number=Plur|Person=3|Tense=Pres|VerbForm=Fin	20	cop	20:cop	_
20	somewhere	somewhere	ADV	RB	_	10	conj	5:advcl:because|10:conj:and	_
21	(	(	PUNCT	-LRB-	_	25	punct	25:punct	Discourse=elaboration-additional:65->64:0|SpaceAfter=No
22	we	we	PRON	PRP	Case=Nom|Number=Plur|Person=1|PronType=Prs	25	nsubj	25:nsubj	Entity=(51-person-giv:act-cf1*-1-ana)
23-24	don't	_	_	_	_	_	_	_	_
23	do	do	AUX	VBP	Mood=Ind|Number=Plur|Person=1|Tense=Pres|VerbForm=Fin	25	aux	25:aux	_
24	n't	not	PART	RB	Polarity=Neg	25	advmod	25:advmod	_
25	know	know	VERB	VB	VerbForm=Inf	20	parataxis	20:parataxis	_
26	where	where	SCONJ	WRB	PronType=Int	25	ccomp	25:ccomp	SpaceAfter=No
27	)	)	PUNCT	-RRB-	_	25	punct	25:punct	_
28	on	on	ADP	IN	_	31	case	31:case	Discourse=same-unit_m:66->64:1
29	a	a	DET	DT	Definite=Ind|PronType=Art	31	det	31:det	Entity=(67-object-new-cf9-3-coref
30	HUGE	huge	ADJ	JJ	Degree=Pos	31	amod	31:amod	_
31	collector	collector	NOUN	NN	Number=Sing	20	nmod	20:nmod:on	Entity=67)
32	—	—	PUNCT	:	_	31	punct	31:punct	Discourse=adversative-concession:67->66:0
33	at	at	ADV	IN	_	37	advmod	37:advmod	_
34	least	least	ADJ	JJS	Degree=Sup	33	fixed	33:fixed	_
35	on	on	ADP	IN	_	37	case	37:case	_
36	the	the	DET	DT	Definite=Def|PronType=Art	37	det	37:det	Entity=(68-abstract-new-cf4-2-sgl
37	scale	scale	NOUN	NN	Number=Sing	10	obl	10:obl:on	_
38	of	of	ADP	IN	_	41	case	41:case	_
39	the	the	DET	DT	Definite=Def|PronType=Art	41	det	41:det	Entity=(69-abstract-new-cf5-3-sgl
40	particle	particle	NOUN	NN	Number=Sing	41	compound	41:compound	Entity=(11-object-giv:act-cf3-1-coref)
41	size	size	NOUN	NN	Number=Sing	37	nmod	37:nmod:of	Entity=69)68)
42	—	—	PUNCT	:	_	37	punct	37:punct	_
43	about	about	ADV	RB	_	45	advmod	45:advmod	Discourse=same-unit_m:68->64:1|Entity=(70-abstract-new-cf10-3-sgl
44	a	a	DET	DT	Definite=Ind|PronType=Art	45	det	45:det	_
45	tenth	tenth	NOUN	NN	Number=Sing|NumForm=Word|NumType=Frac	31	parataxis	31:parataxis	_
46	of	of	ADP	IN	_	49	case	49:case	_
47	a	a	DET	DT	Definite=Ind|PronType=Art	49	det	49:det	Entity=(71-abstract-new-cf11-3-sgl
48	square	square	ADJ	JJ	Degree=Pos	49	amod	49:amod	_
49	meter	meter	NOUN	NN	Number=Sing	45	nmod	45:nmod:of	Entity=71)70)|SpaceAfter=No
50	.	.	PUNCT	.	_	5	punct	5:punct	_
