Wavevector/Frequency Spectrum of Turbulent-Boundary-Layer Pressure

Knowledge of the wavevector/frequency spectrum of wall pressure, P(K,ω) [K = (k1,k3)], for a normal turbulent boundary layer has been largely confined to properties depending on the mean-convective ridge (k1=ω/uc). Recent theoretical work yields the wavevector dependence of P(K,ω), for flow at low Mach numbers, also in the acoustic wave number domain where K ≤ ω/c, except for undetermined functions of ωδ/U∞. In the nonconvective but incompressive domain of wavevectors (important in underwater acoustics), apart from the proportionality to K2 where ω/c ≤ K ≤ δ-1, the scaling, dependence and magnitude of P(K,ω) remain to be established. This domain is approached here by theoretical modeling of the velocity-derivative sources of pressure. The expression for the pressure spectrum derived from the pertinent Poisson equation is cast so that source models may be formulated as spectra in frequency and three-component wavevector, and inhomogeneity normal to the wall treated via dependence of source strength, correlation scales, and mean convection velocity on geometric mean wall distance. A model for the frequency dependence is formulated on the notion of fluctuating local convection. Convection of a frozen wave pattern of the turbulent velocity-product field generates a disturbance in this velocity product, and hence in wall pressure, at frequency ω even if the streamwise wavenumber component of the convected pattern is much smaller than the minimum mean convective wavenumber, ω/U∞. Such generation occurs by virtue of wavenumber components normal to the wall on the order of the ratio of frequency to probable normal convection velocities. The effective rms normal convection velocity is argued to be of the order of the local rms normal turbulence velocity. (This local-convection model for pressure differs essentially from one based jointly on assumption of a space-time quasinormal velocity distribution and application of the local-convection model to two-component velocity spectra.) The model yields the source wavevector/frequency spectrum in terms of the pure wavevector spectrum. A wavevector spectrum constructed to accord with Kronauer-Morrison wave structure yields, in the nonconvective domain where ω-uck1/v*K \u3e \u3e 1 (v* = friction velocity) but K δ \u3e \u3e 1: P(K, ω) = a\u27B(k 1/K)o2v*7K(ω-u ck1)-4 for Ω \u3c \u3c 1, where a\u27 is a constant, B(k1/K) an uncertain anisotropy factor, uc a convection velocity, and Ω = 5(ω-uck1)v/v* a viscous-sublayer parameter; for Ω \u3e \u3e 1, an exponential cutoff is predicted. This sharp cutoff is characteristic of the local-convection model with a normal distribution of convection velocity. An alternative source wavevector spectrum yields form (A) with an additional factor v* K(ω-uck1)-1. A recent wind-tunnel measurement is interpreted to provide an upper limit on a\u27 in either case. Application of the model to the mean-convective domain suggests isotropy of the pertinent Kronauer-Morrison wave strength and hence an angular dependence of P(K,ω) as ctcm(k1/K)2 where ct, cm derive respectively from pure-turbulence and mean-shear source terms and ctcm is comparable with or somewhat less than unity

Family Limited Partnerships Under Attack: Is the End Near?

Family Limited Partnerships (FLPs) represent unique vehicles for transferring wealth, such as family businesses, from one generation to another, permitting parents to gradually transfer business ownership to children while maintaining control over operations.  FLPs also serve as significant shields against the effects of gift and estate taxes, since valuation discounts can be employed to reduce the fair market value of partnership interests transferred to children and other family members.  However, these tax savings have resulted in aggressive audit and court challenges by the IRS.  For accountants, responding to these challenges for their clients means understanding both how the financial and tax aspects of FLPs operate.  This article details the critical nontax aspects of FLPs and presents a thorough examination of current tax developments, including the June 2002 appellate court decisions.  Finally, the article discusses specific steps accountants should take in advising their clients to protect family assets and defend against IRS attacks

Field Work Reflections: Journeys in Knowing and Not-Knowing

In this paper, I retrace my interest in narrative forms of inquiry. I begin by revisiting a series of research projects that I conducted early in my career, describing some of my own dissatisfactions with the methods I used at the time. I move on to a detailed reexamination of my first piece of narrative research, completed during my PhD. In that project I used a narrative pointed psychosocial method in an attempt to develop new knowledge in the field of drugs, ‘race’ and ethnicity. In the final section, I consider what I have learned from this approach in terms of knowing and not-knowing and how I have used this experience to explore different approaches to narrative inquiry. I finish by drawing out some lessons I have learned from these different studies, which I hope might be of relevance to other social work researchers

Coalescing at 8 GeV in the Fermilab Main Injector

For Project X, it is planned to inject a beam of 3 10**11 particles per bunch into the Main Injector. To prepare for this by studying the effects of higher intensity bunches in the Main Injector it is necessary to perform coalescing at 8 GeV. The results of a series of experiments and simulations of 8 GeV coalescing are presented. To increase the coalescing efficiency adiabatic reduction of the 53 MHz RF is required, resulting in ~70% coalescing efficiency of 5 initial bunches. Data using wall current monitors has been taken to compare previous work and new simulations for 53 MHz RF reduction, bunch rotations and coalescing, good agreement between experiment and simulation was found. Possible schemes to increase the coalescing efficiency and generate even higher intensity bunches are discussed. These require improving the timing resolution of the low level RF and/or tuning the adiabatic voltage reduction of the 53 MHz.Comment: 3 pp. 3rd International Particle Accelerator Conference (IPAC 2012) 20-25 May 2012, New Orleans, Louisian

The young stellar population of Lynds 1340. An infrared view

We present results of an infrared study of the molecular cloud Lynds 1340, forming three groups of low and intermediate-mass stars. Our goals are to identify and characterise the young stellar population of the cloud, study the relationships between the properties of the cloud and the emergent stellar groups, and integrate L1340 into the picture of the star-forming activity of our Galactic environment. We selected candidate young stellar objects from the Spitzer and WISE data bases using various published color criteria, and classified them based on the slope of the spectral energy distribution. We identified 170 Class II, 27 Flat SED, and Class 0/I sources. High angular resolution near-infrared observations of the RNO 7 cluster, embedded in L1340, revealed eight new young stars of near-infrared excess. The surface density distribution of young stellar objects shows three groups, associated with the three major molecular clumps of L1340, each consisting of less than 100 members, including both pre-main sequence stars and embedded protostars. New Herbig--Haro objects were identified in the Spitzer images. Our results demonstrate that L1340 is a prolific star-forming region of our Galactic environment in which several specific properties of the intermediate-mass mode of star formation can be studied in detail.Comment: 73 pages, 33 figures, 15 tables. Accepted for publication in ApJ

Spontaneous Iliopsoas Hematoma following Microvascular Free Tissue Transfer.

Spontaneous hematoma within the iliopsoas muscle (SIH) is a rare complication most commonly seen in coagulopathic patients. Often, patients undergoing microvascular free tissue transfer are anticoagulated for anastomotic patency. Here we describe two cases of postoperative SIH following contralateral anterolateral thigh (ALT) free tissue transfer for reconstruction of oncologic head and neck defects. Both patients described hip pain after mobilization and had a corresponding acute blood loss anemia. Diagnosis of SIH was confirmed by CT and both patients were managed conservatively. Given that anticoagulation is a common practice following head and neck free tissue transfer, surgeons should be aware of this potential complication

A study of the phase transition in the usual statistical model for nuclear multifragmentation

We use a simplified model which is based on the same physics as inherent in most statistical models for nuclear multifragmentation. The simplified model allows exact calculations for thermodynamic properties of systems of large number of particles. This enables us to study a phase transition in the model. A first order phase transition can be tracked down. There are significant differences between this phase transition and some other well-known cases

Hyperuniform long-range correlations are a signature of disordered jammed hard-particle packings

We show that quasi-long-range (QLR) pair correlations that decay asymptotically with scaling $r^{-(d+1)}$ in $d$-dimensional Euclidean space $\mathbb{R}^d$, trademarks of certain quantum systems and cosmological structures, are a universal signature of maximally random jammed (MRJ) hard-particle packings. We introduce a novel hyperuniformity descriptor in MRJ packings by studying local-volume-fraction fluctuations and show that infinite-wavelength fluctuations vanish even for packings with size- and shape-distributions. Special void statistics induce hyperuniformity and QLR pair correlations.Comment: 10 pages, 3 figures; changes to figures and text based on review process; accepted for publication at Phys. Rev. Let

I wish he'd listen: Client-centered interviewing approaches are associated with higher compliance with behavioral modification advice in pet dog owners

In the UK, over 40,000 dogs are given up annually to shelters or euthanized due to problem behaviors. It may be possible to reduce these numbers through behavior counseling and development of a behavior modification plan (BMP) by a canine professional (CP). However, if the client does not or cannot adhere to the BMP the dog's prospects may be compromised. This study explored the experience of the initial behavior consultation and possible reasons for adhering to (or not) the BMP from the client's perspective. An online survey solicited the opinions of canine behavior clients who had sought professional help in the UK for their dog's unwanted behavior within the last 2 years. Principal Component Analysis of Likert scale statements revealed one significant PC (P < 0.001) that explained 57% of the variation in the data and was significantly correlated with BMP compliance (r = 0.567, P < 0.001). Specifically, believing the plan was right for their dog and having CP support throughout to achieve behavior improvement through the implementation of a mutually agreed BMP were important. Qualitative thematic analysis of free text responses regarding motivation for future client BMP compliance echoed these factors. Conversely, a negative consultation experience was created by CPs adopting an authoritarian or ‘telling’ approach with their clients for example, making them feel judged. This was associated with a lack of BMP compliance. Essentially, CPs who involved their clients in BMP development were perceived as creating a positive experience of the initial behavior consultation and as a result were able to promote client BMP adherence and improvement in unwanted behavior improvement. This CP approach, which adopts a nurturing rather than an authoritarian strategy, has been termed Client-Centered Interviewing (CCI). The main thing about CCI is the client is an equal partner in the process. The core conditions are as per Rogers and Egan of empathy, congruence and unconditional positive regard. CCI builds on empathy with the client, avoids inappropriately challenging client beliefs by gently exploring options without being judgemental, clearly explains the likely cause of the behavior and the plan to resolve it, and provides a BMP that is bespoke and flexible. Future research is required to validate the findings, for example through a prospective comparison of Client-Centered Interviewing versus an instructional (authoritarian) approach. Crucially, the impact of Client-Centered Interviewing on canine welfare must also be evaluated