Luis Javier Perez-Lorenzo's research while affiliated with Yale University and other places

Publications (10)

Article
Time of flight (TOF) and energy analysis in vacuum are used in series to determine jet velocity U j , diameter d j , electrical potential V j and energy dissipated Δ V at the breakup point of electrified nanojets of the ionic liquid 1-Ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (EMI-FAP) (Ignat'ev et al. , J. Fluorine Chem. ,...
Article
Full-text available
The COVID-19 pandemic has presented an acute shortage of regulation-tested masks. Many of the alternatives available to hospitals have not been certified, leaving uncertainty about their ability to properly protect healthcare workers from SARS-CoV-2 transmission. For situations where regulatory methods are not accessible, we present experimental me...
Article
Hypothesis: While the lack of efficient tools yielding controllable uniform saturation ratios (S) has delayed basic experimental heterogeneous nucleation studies, common diffusive condensation particle counters (DCPCs) could fill this gap if their S-variation was minimized by increasing the proportion of sheath gas (σ) surrounding a central core of...
Article
The Chronic Bee Paralysis Virus (CBPV), extracted from sick or dead bees, was studied by mobility measurements via electrospray charge reduction with a differential mobility analyzer (DMA) of unusually high resolution. Three different particles are observed. The most abundant one contributes a mobility peak at 38.3 nm, approximately as expected for...
Article
Singly charged clusters [C+A-] n C+ or [C+A-] n A- of two salts [C+A-] are produced by electrospray ionization of alcohol solutions of the ionic liquids 1-ethyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate (EMI-FAP) and 1,2-dimethyl-3-propylimidazolium-methide (DMPI-Me). The rate of neutral pair evaporation into [C+A-] + [C+A-]n-1C+...
Article
A differential mobility analyzer for high-mobility resolution (1/FWHM∼30) classification of 1–67 nm particles is designed to analyze viral particles. Inner and outer electrode radii of 1.01 and 2 cm (at the outlet slit) and a 11.6 cm long column achieve this range at a sheath gas flow (Q) and aerosol flow (q) of 30 and 1 L/min. Turbulent transition...
Article
The transfer function of TSI's widely used 3071 Differential Mobility Analyzer (DMA) widens drastically when the flow rate Q of sheath gas exceeds 30–40 lit/min, limiting its ability to resolve very small particles. This flow instability is unexpected at the prevailing relatively small Reynolds number (Re < 400). Here, we note that the rings holdin...
Article
Full-text available
Two fast electrometer circuits (10¹¹ and 10¹² V/A) are installed in a Faraday cage having a relatively small residence time. Removing readily distinguishable occasional spikes, the root mean square (r.m.s.) noise level at 10¹² V/A is 0.11 fA when acquiring data at 1 Hz. This value is close to the expected thermal resistor noise at room temperature...
Article
The development of efficient blowers for battery-operated vacuum cleaners is exploited to increase the portability of high resolution DMAs. A Halfmini DMA run by the blower of the irobot Roomba 500 powered by a variable DC voltage is tested with electrosprayed molecular ions and the serum albumin protein. Sheath gas flow rates Q from 13 Lit/min up...

Citations

... In particular, it has been shown that particle (also referred to as droplet) dispersion in the original expiratory direction (i.e., directly through the mask) is significantly reduced [24,25]. A number of studies have also investigated the filtration efficiency of masks under different conditions (see for example [26][27][28]). Whilst flow is reduced through the mask wall, studies have identified significant flow leakage at the side and top edges of masks (including N95, surgical, cloth, homemade). ...
... For example, the FDA particle filtration efficiency (PFE) test method (ASTM F2299) allows over an order in magnitude in range from 0.5 to 25 cm s -1 (ASTM International, 2017b). This latitude in test method conditions might contribute to previously observed variability in the filtration efficiency of surgical masks, which are categorized into three levels based on this test (Rengasamy et al., 2017;Lam et al., 2020;Schilling et al., 2020). To the same effect, the FDA's bacterial filtration efficiency (BFE) test method (ASTM, 2101) specifies a total flowrate of 28.3 L min -1 , but does not specify surface area, essentially permitting a range of face velocities (ASTM International, 2019). ...
... A screen made of nylon with a mesh size of 50 µm is stretched between the inner and outer tube to laminarise the sheath flow. Downstream of the screen, we designed a cone with a length of 65 mm, forcing the flow to accelerate as the inner tube diameter is reduced from 26 to 10 mm (Perez-Lorenzo et al., 2020). To reduce turbulence formation, the cone angle is kept small with 7 • inclination. ...
... The sample was diluted by means of the Dekati ® DEED, a PMP-compliant conditioning system. Nucleation particle detection was performed through an advanced HM-DMA characterized by high resolution in the size range 5-30 nm [25] and fast response time down to 1 s [26]. The instrument is a prototype that was developed within the European project Sureal-23. ...